From 5500cbf0e420a6d643835ec05f35abb170e3e443 Mon Sep 17 00:00:00 2001 From: Jes Cok Date: Thu, 25 Sep 2025 04:41:12 +0000 Subject: [PATCH 001/229] debug/elf: prevent offset overflow When applying relocations, a malformed ELF file can provide an offset that, when added to the relocation size, overflows. This wrapped-around value could then incorrectly pass the bounds check, leading to a panic when the slice is accessed with the original large offset. This change eliminates the manual bounds and overflow checks and writes a relocation to slice by calling putUint. The putUint helper function centralizes the logic for validating slice access, correctly handling both out-of-bounds and integer overflow conditions. This simplifies the relocation code and improves robustness when parsing malformed ELF files. Fixes #75516 Change-Id: I00d806bf5501a9bf70200585ba4fd0475d7b2ddc GitHub-Last-Rev: 49144311d31fecc63cb81b6c31bf9a206acb0596 GitHub-Pull-Request: golang/go#75522 Reviewed-on: https://go-review.googlesource.com/c/go/+/705075 Reviewed-by: Florian Lehner LUCI-TryBot-Result: Go LUCI Reviewed-by: Junyang Shao Auto-Submit: Ian Lance Taylor Reviewed-by: Michael Knyszek Reviewed-by: Ian Lance Taylor Commit-Queue: Ian Lance Taylor --- src/debug/elf/file.go | 160 +++++++++++++++--------------------------- 1 file changed, 57 insertions(+), 103 deletions(-) diff --git a/src/debug/elf/file.go b/src/debug/elf/file.go index 50452b5bef45f4..1d56a06c3fb221 100644 --- a/src/debug/elf/file.go +++ b/src/debug/elf/file.go @@ -25,6 +25,7 @@ import ( "internal/saferio" "internal/zstd" "io" + "math" "os" "strings" "unsafe" @@ -830,17 +831,9 @@ func (f *File) applyRelocationsAMD64(dst []byte, rels []byte) error { switch t { case R_X86_64_64: - if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val64 := sym.Value + uint64(rela.Addend) - f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val64) + putUint(f.ByteOrder, dst, rela.Off, 8, sym.Value, rela.Addend, false) case R_X86_64_32: - if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, rela.Off, 4, sym.Value, rela.Addend, false) } } @@ -872,12 +865,7 @@ func (f *File) applyRelocations386(dst []byte, rels []byte) error { sym := &symbols[symNo-1] if t == R_386_32 { - if rel.Off+4 >= uint32(len(dst)) { - continue - } - val := f.ByteOrder.Uint32(dst[rel.Off : rel.Off+4]) - val += uint32(sym.Value) - f.ByteOrder.PutUint32(dst[rel.Off:rel.Off+4], val) + putUint(f.ByteOrder, dst, uint64(rel.Off), 4, sym.Value, 0, true) } } @@ -910,12 +898,7 @@ func (f *File) applyRelocationsARM(dst []byte, rels []byte) error { switch t { case R_ARM_ABS32: - if rel.Off+4 >= uint32(len(dst)) { - continue - } - val := f.ByteOrder.Uint32(dst[rel.Off : rel.Off+4]) - val += uint32(sym.Value) - f.ByteOrder.PutUint32(dst[rel.Off:rel.Off+4], val) + putUint(f.ByteOrder, dst, uint64(rel.Off), 4, sym.Value, 0, true) } } @@ -955,17 +938,9 @@ func (f *File) applyRelocationsARM64(dst []byte, rels []byte) error { switch t { case R_AARCH64_ABS64: - if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val64 := sym.Value + uint64(rela.Addend) - f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val64) + putUint(f.ByteOrder, dst, rela.Off, 8, sym.Value, rela.Addend, false) case R_AARCH64_ABS32: - if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, rela.Off, 4, sym.Value, rela.Addend, false) } } @@ -1001,11 +976,7 @@ func (f *File) applyRelocationsPPC(dst []byte, rels []byte) error { switch t { case R_PPC_ADDR32: - if rela.Off+4 >= uint32(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, uint64(rela.Off), 4, sym.Value, 0, false) } } @@ -1041,17 +1012,9 @@ func (f *File) applyRelocationsPPC64(dst []byte, rels []byte) error { switch t { case R_PPC64_ADDR64: - if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val64 := sym.Value + uint64(rela.Addend) - f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val64) + putUint(f.ByteOrder, dst, rela.Off, 8, sym.Value, rela.Addend, false) case R_PPC64_ADDR32: - if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, rela.Off, 4, sym.Value, rela.Addend, false) } } @@ -1084,12 +1047,7 @@ func (f *File) applyRelocationsMIPS(dst []byte, rels []byte) error { switch t { case R_MIPS_32: - if rel.Off+4 >= uint32(len(dst)) { - continue - } - val := f.ByteOrder.Uint32(dst[rel.Off : rel.Off+4]) - val += uint32(sym.Value) - f.ByteOrder.PutUint32(dst[rel.Off:rel.Off+4], val) + putUint(f.ByteOrder, dst, uint64(rel.Off), 4, sym.Value, 0, true) } } @@ -1132,17 +1090,9 @@ func (f *File) applyRelocationsMIPS64(dst []byte, rels []byte) error { switch t { case R_MIPS_64: - if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val64 := sym.Value + uint64(rela.Addend) - f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val64) + putUint(f.ByteOrder, dst, rela.Off, 8, sym.Value, rela.Addend, false) case R_MIPS_32: - if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, rela.Off, 4, sym.Value, rela.Addend, false) } } @@ -1180,17 +1130,9 @@ func (f *File) applyRelocationsLOONG64(dst []byte, rels []byte) error { switch t { case R_LARCH_64: - if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val64 := sym.Value + uint64(rela.Addend) - f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val64) + putUint(f.ByteOrder, dst, rela.Off, 8, sym.Value, rela.Addend, false) case R_LARCH_32: - if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, rela.Off, 4, sym.Value, rela.Addend, false) } } @@ -1226,17 +1168,9 @@ func (f *File) applyRelocationsRISCV64(dst []byte, rels []byte) error { switch t { case R_RISCV_64: - if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val64 := sym.Value + uint64(rela.Addend) - f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val64) + putUint(f.ByteOrder, dst, rela.Off, 8, sym.Value, rela.Addend, false) case R_RISCV_32: - if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, rela.Off, 4, sym.Value, rela.Addend, false) } } @@ -1272,17 +1206,9 @@ func (f *File) applyRelocationss390x(dst []byte, rels []byte) error { switch t { case R_390_64: - if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val64 := sym.Value + uint64(rela.Addend) - f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val64) + putUint(f.ByteOrder, dst, rela.Off, 8, sym.Value, rela.Addend, false) case R_390_32: - if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, rela.Off, 4, sym.Value, rela.Addend, false) } } @@ -1318,17 +1244,10 @@ func (f *File) applyRelocationsSPARC64(dst []byte, rels []byte) error { switch t { case R_SPARC_64, R_SPARC_UA64: - if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val64 := sym.Value + uint64(rela.Addend) - f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], val64) + putUint(f.ByteOrder, dst, rela.Off, 8, sym.Value, rela.Addend, false) + case R_SPARC_32, R_SPARC_UA32: - if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 { - continue - } - val32 := uint32(sym.Value) + uint32(rela.Addend) - f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], val32) + putUint(f.ByteOrder, dst, rela.Off, 4, sym.Value, rela.Addend, false) } } @@ -1903,3 +1822,38 @@ type nobitsSectionReader struct{} func (*nobitsSectionReader) ReadAt(p []byte, off int64) (n int, err error) { return 0, errors.New("unexpected read from SHT_NOBITS section") } + +// putUint writes a relocation to slice +// at offset start of length length (4 or 8 bytes), +// adding sym+addend to the existing value if readUint is true, +// or just writing sym+addend if readUint is false. +// If the write would extend beyond the end of slice, putUint does nothing. +// If the addend is negative, putUint does nothing. +// If the addition would overflow, putUint does nothing. +func putUint(byteOrder binary.ByteOrder, slice []byte, start, length, sym uint64, addend int64, readUint bool) { + if start+length > uint64(len(slice)) || math.MaxUint64-start < length { + return + } + if addend < 0 { + return + } + + s := slice[start : start+length] + + switch length { + case 4: + ae := uint32(addend) + if readUint { + ae += byteOrder.Uint32(s) + } + byteOrder.PutUint32(s, uint32(sym)+ae) + case 8: + ae := uint64(addend) + if readUint { + ae += byteOrder.Uint64(s) + } + byteOrder.PutUint64(s, sym+ae) + default: + panic("can't happen") + } +} From 6d51f932575284d6e78baa5e98f47f737a9f5b19 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Mon, 29 Sep 2025 14:14:28 +0200 Subject: [PATCH 002/229] runtime: jump instead of branch in netbsd/arm64 entry point CL 706175 removed the NOFRAME directive from _rt0_arm64_netbsd but did not change the BL instruction to a JMP instruction. This causes the frame pointer to be stored on the stack, this making direct load from RSP to be off by 8 bytes. Cq-Include-Trybots: luci.golang.try:gotip-netbsd-arm64 Change-Id: I0c212fbaba74cfce508f961090dc6e66154c3054 Reviewed-on: https://go-review.googlesource.com/c/go/+/707675 LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Pratt Reviewed-by: Cherry Mui --- src/runtime/rt0_netbsd_arm64.s | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/runtime/rt0_netbsd_arm64.s b/src/runtime/rt0_netbsd_arm64.s index 07fb0a1240aec5..80802209b78f12 100644 --- a/src/runtime/rt0_netbsd_arm64.s +++ b/src/runtime/rt0_netbsd_arm64.s @@ -7,7 +7,7 @@ TEXT _rt0_arm64_netbsd(SB),NOSPLIT,$0 MOVD 0(RSP), R0 // argc ADD $8, RSP, R1 // argv - BL main(SB) + JMP main(SB) // When building with -buildmode=c-shared, this symbol is called when the shared // library is loaded. From d42d56b764f4c8b06aaa2de2dc9c1d2171e79490 Mon Sep 17 00:00:00 2001 From: apocelipes Date: Wed, 24 Sep 2025 03:23:03 +0000 Subject: [PATCH 003/229] encoding/xml: make use of reflect.TypeAssert MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To make the code more readable and improve performance: goos: darwin goarch: arm64 pkg: encoding/xml cpu: Apple M4 │ old │ new │ │ sec/op │ sec/op vs base │ Marshal-10 1.902µ ± 1% 1.496µ ± 1% -21.37% (p=0.000 n=10) Unmarshal-10 3.877µ ± 1% 3.418µ ± 2% -11.84% (p=0.000 n=10) HTMLAutoClose-10 1.314µ ± 3% 1.333µ ± 1% ~ (p=0.270 n=10) geomean 2.132µ 1.896µ -11.07% │ old │ new │ │ B/op │ B/op vs base │ Marshal-10 5.570Ki ± 0% 5.570Ki ± 0% ~ (p=1.000 n=10) ¹ Unmarshal-10 7.586Ki ± 0% 7.555Ki ± 0% -0.41% (p=0.000 n=10) HTMLAutoClose-10 3.496Ki ± 0% 3.496Ki ± 0% ~ (p=1.000 n=10) ¹ geomean 5.286Ki 5.279Ki -0.14% ¹ all samples are equal │ old │ new │ │ allocs/op │ allocs/op vs base │ Marshal-10 23.00 ± 0% 23.00 ± 0% ~ (p=1.000 n=10) ¹ Unmarshal-10 185.0 ± 0% 184.0 ± 0% -0.54% (p=0.000 n=10) HTMLAutoClose-10 93.00 ± 0% 93.00 ± 0% ~ (p=1.000 n=10) ¹ geomean 73.42 73.28 -0.18% ¹ all samples are equal Updates #62121 Change-Id: Ie458e7458d4358c380374571d380ca3b65ca87bb GitHub-Last-Rev: bb6bb3039328ca1d53ee3d56fd6597109ed76b09 GitHub-Pull-Request: golang/go#75483 Reviewed-on: https://go-review.googlesource.com/c/go/+/704215 LUCI-TryBot-Result: Go LUCI Auto-Submit: Keith Randall Reviewed-by: Keith Randall Reviewed-by: Keith Randall Reviewed-by: Carlos Amedee --- src/encoding/xml/marshal.go | 127 ++++++++++++++++++++---------------- src/encoding/xml/read.go | 77 +++++++++++++--------- 2 files changed, 117 insertions(+), 87 deletions(-) diff --git a/src/encoding/xml/marshal.go b/src/encoding/xml/marshal.go index 133503fa2de41c..13fbeeeedc75ce 100644 --- a/src/encoding/xml/marshal.go +++ b/src/encoding/xml/marshal.go @@ -416,12 +416,6 @@ func (p *printer) popPrefix() { } } -var ( - marshalerType = reflect.TypeFor[Marshaler]() - marshalerAttrType = reflect.TypeFor[MarshalerAttr]() - textMarshalerType = reflect.TypeFor[encoding.TextMarshaler]() -) - // marshalValue writes one or more XML elements representing val. // If val was obtained from a struct field, finfo must have its details. func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo, startTemplate *StartElement) error { @@ -450,24 +444,32 @@ func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo, startTemplat typ := val.Type() // Check for marshaler. - if val.CanInterface() && typ.Implements(marshalerType) { - return p.marshalInterface(val.Interface().(Marshaler), defaultStart(typ, finfo, startTemplate)) + if val.CanInterface() { + if marshaler, ok := reflect.TypeAssert[Marshaler](val); ok { + return p.marshalInterface(marshaler, defaultStart(typ, finfo, startTemplate)) + } } if val.CanAddr() { pv := val.Addr() - if pv.CanInterface() && pv.Type().Implements(marshalerType) { - return p.marshalInterface(pv.Interface().(Marshaler), defaultStart(pv.Type(), finfo, startTemplate)) + if pv.CanInterface() { + if marshaler, ok := reflect.TypeAssert[Marshaler](pv); ok { + return p.marshalInterface(marshaler, defaultStart(pv.Type(), finfo, startTemplate)) + } } } // Check for text marshaler. - if val.CanInterface() && typ.Implements(textMarshalerType) { - return p.marshalTextInterface(val.Interface().(encoding.TextMarshaler), defaultStart(typ, finfo, startTemplate)) + if val.CanInterface() { + if textMarshaler, ok := reflect.TypeAssert[encoding.TextMarshaler](val); ok { + return p.marshalTextInterface(textMarshaler, defaultStart(typ, finfo, startTemplate)) + } } if val.CanAddr() { pv := val.Addr() - if pv.CanInterface() && pv.Type().Implements(textMarshalerType) { - return p.marshalTextInterface(pv.Interface().(encoding.TextMarshaler), defaultStart(pv.Type(), finfo, startTemplate)) + if pv.CanInterface() { + if textMarshaler, ok := reflect.TypeAssert[encoding.TextMarshaler](pv); ok { + return p.marshalTextInterface(textMarshaler, defaultStart(pv.Type(), finfo, startTemplate)) + } } } @@ -503,7 +505,7 @@ func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo, startTemplat start.Name.Space, start.Name.Local = xmlname.xmlns, xmlname.name } else { fv := xmlname.value(val, dontInitNilPointers) - if v, ok := fv.Interface().(Name); ok && v.Local != "" { + if v, ok := reflect.TypeAssert[Name](fv); ok && v.Local != "" { start.Name = v } } @@ -580,21 +582,9 @@ func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo, startTemplat // marshalAttr marshals an attribute with the given name and value, adding to start.Attr. func (p *printer) marshalAttr(start *StartElement, name Name, val reflect.Value) error { - if val.CanInterface() && val.Type().Implements(marshalerAttrType) { - attr, err := val.Interface().(MarshalerAttr).MarshalXMLAttr(name) - if err != nil { - return err - } - if attr.Name.Local != "" { - start.Attr = append(start.Attr, attr) - } - return nil - } - - if val.CanAddr() { - pv := val.Addr() - if pv.CanInterface() && pv.Type().Implements(marshalerAttrType) { - attr, err := pv.Interface().(MarshalerAttr).MarshalXMLAttr(name) + if val.CanInterface() { + if marshaler, ok := reflect.TypeAssert[MarshalerAttr](val); ok { + attr, err := marshaler.MarshalXMLAttr(name) if err != nil { return err } @@ -605,19 +595,25 @@ func (p *printer) marshalAttr(start *StartElement, name Name, val reflect.Value) } } - if val.CanInterface() && val.Type().Implements(textMarshalerType) { - text, err := val.Interface().(encoding.TextMarshaler).MarshalText() - if err != nil { - return err + if val.CanAddr() { + pv := val.Addr() + if pv.CanInterface() { + if marshaler, ok := reflect.TypeAssert[MarshalerAttr](pv); ok { + attr, err := marshaler.MarshalXMLAttr(name) + if err != nil { + return err + } + if attr.Name.Local != "" { + start.Attr = append(start.Attr, attr) + } + return nil + } } - start.Attr = append(start.Attr, Attr{name, string(text)}) - return nil } - if val.CanAddr() { - pv := val.Addr() - if pv.CanInterface() && pv.Type().Implements(textMarshalerType) { - text, err := pv.Interface().(encoding.TextMarshaler).MarshalText() + if val.CanInterface() { + if textMarshaler, ok := reflect.TypeAssert[encoding.TextMarshaler](val); ok { + text, err := textMarshaler.MarshalText() if err != nil { return err } @@ -626,6 +622,20 @@ func (p *printer) marshalAttr(start *StartElement, name Name, val reflect.Value) } } + if val.CanAddr() { + pv := val.Addr() + if pv.CanInterface() { + if textMarshaler, ok := reflect.TypeAssert[encoding.TextMarshaler](pv); ok { + text, err := textMarshaler.MarshalText() + if err != nil { + return err + } + start.Attr = append(start.Attr, Attr{name, string(text)}) + return nil + } + } + } + // Dereference or skip nil pointer, interface values. switch val.Kind() { case reflect.Pointer, reflect.Interface: @@ -647,7 +657,8 @@ func (p *printer) marshalAttr(start *StartElement, name Name, val reflect.Value) } if val.Type() == attrType { - start.Attr = append(start.Attr, val.Interface().(Attr)) + attr, _ := reflect.TypeAssert[Attr](val) + start.Attr = append(start.Attr, attr) return nil } @@ -854,20 +865,9 @@ func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error { if err := s.trim(finfo.parents); err != nil { return err } - if vf.CanInterface() && vf.Type().Implements(textMarshalerType) { - data, err := vf.Interface().(encoding.TextMarshaler).MarshalText() - if err != nil { - return err - } - if err := emit(p, data); err != nil { - return err - } - continue - } - if vf.CanAddr() { - pv := vf.Addr() - if pv.CanInterface() && pv.Type().Implements(textMarshalerType) { - data, err := pv.Interface().(encoding.TextMarshaler).MarshalText() + if vf.CanInterface() { + if textMarshaler, ok := reflect.TypeAssert[encoding.TextMarshaler](vf); ok { + data, err := textMarshaler.MarshalText() if err != nil { return err } @@ -877,6 +877,21 @@ func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error { continue } } + if vf.CanAddr() { + pv := vf.Addr() + if pv.CanInterface() { + if textMarshaler, ok := reflect.TypeAssert[encoding.TextMarshaler](pv); ok { + data, err := textMarshaler.MarshalText() + if err != nil { + return err + } + if err := emit(p, data); err != nil { + return err + } + continue + } + } + } var scratch [64]byte vf = indirect(vf) @@ -902,7 +917,7 @@ func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error { return err } case reflect.Slice: - if elem, ok := vf.Interface().([]byte); ok { + if elem, ok := reflect.TypeAssert[[]byte](vf); ok { if err := emit(p, elem); err != nil { return err } diff --git a/src/encoding/xml/read.go b/src/encoding/xml/read.go index af25c20f0618dc..d3cb74b2c4311a 100644 --- a/src/encoding/xml/read.go +++ b/src/encoding/xml/read.go @@ -255,28 +255,36 @@ func (d *Decoder) unmarshalAttr(val reflect.Value, attr Attr) error { } val = val.Elem() } - if val.CanInterface() && val.Type().Implements(unmarshalerAttrType) { + if val.CanInterface() { // This is an unmarshaler with a non-pointer receiver, // so it's likely to be incorrect, but we do what we're told. - return val.Interface().(UnmarshalerAttr).UnmarshalXMLAttr(attr) + if unmarshaler, ok := reflect.TypeAssert[UnmarshalerAttr](val); ok { + return unmarshaler.UnmarshalXMLAttr(attr) + } } if val.CanAddr() { pv := val.Addr() - if pv.CanInterface() && pv.Type().Implements(unmarshalerAttrType) { - return pv.Interface().(UnmarshalerAttr).UnmarshalXMLAttr(attr) + if pv.CanInterface() { + if unmarshaler, ok := reflect.TypeAssert[UnmarshalerAttr](pv); ok { + return unmarshaler.UnmarshalXMLAttr(attr) + } } } // Not an UnmarshalerAttr; try encoding.TextUnmarshaler. - if val.CanInterface() && val.Type().Implements(textUnmarshalerType) { + if val.CanInterface() { // This is an unmarshaler with a non-pointer receiver, // so it's likely to be incorrect, but we do what we're told. - return val.Interface().(encoding.TextUnmarshaler).UnmarshalText([]byte(attr.Value)) + if textUnmarshaler, ok := reflect.TypeAssert[encoding.TextUnmarshaler](val); ok { + return textUnmarshaler.UnmarshalText([]byte(attr.Value)) + } } if val.CanAddr() { pv := val.Addr() - if pv.CanInterface() && pv.Type().Implements(textUnmarshalerType) { - return pv.Interface().(encoding.TextUnmarshaler).UnmarshalText([]byte(attr.Value)) + if pv.CanInterface() { + if textUnmarshaler, ok := reflect.TypeAssert[encoding.TextUnmarshaler](pv); ok { + return textUnmarshaler.UnmarshalText([]byte(attr.Value)) + } } } @@ -303,12 +311,7 @@ func (d *Decoder) unmarshalAttr(val reflect.Value, attr Attr) error { return copyValue(val, []byte(attr.Value)) } -var ( - attrType = reflect.TypeFor[Attr]() - unmarshalerType = reflect.TypeFor[Unmarshaler]() - unmarshalerAttrType = reflect.TypeFor[UnmarshalerAttr]() - textUnmarshalerType = reflect.TypeFor[encoding.TextUnmarshaler]() -) +var attrType = reflect.TypeFor[Attr]() const ( maxUnmarshalDepth = 10000 @@ -352,27 +355,35 @@ func (d *Decoder) unmarshal(val reflect.Value, start *StartElement, depth int) e val = val.Elem() } - if val.CanInterface() && val.Type().Implements(unmarshalerType) { + if val.CanInterface() { // This is an unmarshaler with a non-pointer receiver, // so it's likely to be incorrect, but we do what we're told. - return d.unmarshalInterface(val.Interface().(Unmarshaler), start) + if unmarshaler, ok := reflect.TypeAssert[Unmarshaler](val); ok { + return d.unmarshalInterface(unmarshaler, start) + } } if val.CanAddr() { pv := val.Addr() - if pv.CanInterface() && pv.Type().Implements(unmarshalerType) { - return d.unmarshalInterface(pv.Interface().(Unmarshaler), start) + if pv.CanInterface() { + if unmarshaler, ok := reflect.TypeAssert[Unmarshaler](pv); ok { + return d.unmarshalInterface(unmarshaler, start) + } } } - if val.CanInterface() && val.Type().Implements(textUnmarshalerType) { - return d.unmarshalTextInterface(val.Interface().(encoding.TextUnmarshaler)) + if val.CanInterface() { + if textUnmarshaler, ok := reflect.TypeAssert[encoding.TextUnmarshaler](val); ok { + return d.unmarshalTextInterface(textUnmarshaler) + } } if val.CanAddr() { pv := val.Addr() - if pv.CanInterface() && pv.Type().Implements(textUnmarshalerType) { - return d.unmarshalTextInterface(pv.Interface().(encoding.TextUnmarshaler)) + if pv.CanInterface() { + if textUnmarshaler, ok := reflect.TypeAssert[encoding.TextUnmarshaler](pv); ok { + return d.unmarshalTextInterface(textUnmarshaler) + } } } @@ -453,7 +464,7 @@ func (d *Decoder) unmarshal(val reflect.Value, start *StartElement, depth int) e return UnmarshalError(e) } fv := finfo.value(sv, initNilPointers) - if _, ok := fv.Interface().(Name); ok { + if _, ok := reflect.TypeAssert[Name](fv); ok { fv.Set(reflect.ValueOf(start.Name)) } } @@ -578,20 +589,24 @@ Loop: } } - if saveData.IsValid() && saveData.CanInterface() && saveData.Type().Implements(textUnmarshalerType) { - if err := saveData.Interface().(encoding.TextUnmarshaler).UnmarshalText(data); err != nil { - return err + if saveData.IsValid() && saveData.CanInterface() { + if textUnmarshaler, ok := reflect.TypeAssert[encoding.TextUnmarshaler](saveData); ok { + if err := textUnmarshaler.UnmarshalText(data); err != nil { + return err + } + saveData = reflect.Value{} } - saveData = reflect.Value{} } if saveData.IsValid() && saveData.CanAddr() { pv := saveData.Addr() - if pv.CanInterface() && pv.Type().Implements(textUnmarshalerType) { - if err := pv.Interface().(encoding.TextUnmarshaler).UnmarshalText(data); err != nil { - return err + if pv.CanInterface() { + if textUnmarshaler, ok := reflect.TypeAssert[encoding.TextUnmarshaler](pv); ok { + if err := textUnmarshaler.UnmarshalText(data); err != nil { + return err + } + saveData = reflect.Value{} } - saveData = reflect.Value{} } } From fe3ba74b9e6e3385cbf7c2f3a9c0b72baeac4b01 Mon Sep 17 00:00:00 2001 From: Richard Miller Date: Sat, 27 Sep 2025 19:45:36 +0100 Subject: [PATCH 004/229] cmd/link: skip TestFlagW on platforms without DWARF symbol table As with other DWARF tests, don't run TestFlagW on platforms where executables don't have a DWARF symbol table. Fixes #75585 Change-Id: I81014bf59b15e30ac1b2a7d24a52f9647db46c26 Reviewed-on: https://go-review.googlesource.com/c/go/+/706418 Reviewed-by: Cherry Mui LUCI-TryBot-Result: Go LUCI Reviewed-by: Carlos Amedee --- src/cmd/link/dwarf_test.go | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/cmd/link/dwarf_test.go b/src/cmd/link/dwarf_test.go index 6a60a746a5b48b..4fce358e602de5 100644 --- a/src/cmd/link/dwarf_test.go +++ b/src/cmd/link/dwarf_test.go @@ -364,6 +364,10 @@ func TestFlagW(t *testing.T) { if runtime.GOOS == "aix" { t.Skip("internal/xcoff cannot parse file without symbol table") } + if !platform.ExecutableHasDWARF(runtime.GOOS, runtime.GOARCH) { + t.Skipf("skipping on %s/%s: no DWARF symbol table in executables", runtime.GOOS, runtime.GOARCH) + } + t.Parallel() tmpdir := t.TempDir() From ae8eba071b228dd9e05de0b0c338f3d941a0a43f Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Sun, 28 Sep 2025 21:25:24 -0700 Subject: [PATCH 005/229] cmd/link: use correct length for pcln.cutab The pcln.cutab slice holds uint32 elements, as can be seen in the runtime.moduledata type. The slice was being created with the len (and cap) set to the size of the slice, which means that the count was four times too large. This patch sets the correct len/cap. This doesn't matter for the runtime because nothing looks at the len of cutab. Since the incorrect len is larger, all valid indexes remain valid. Using the correct length means that more invalid indexes will be caught at run time, but such cases are unlikely. Still, using the correct len is less confusing. While we're here use the simpler sliceSym for pcln.pclntab. Change-Id: I09f680b3287467120d994b171c86c784085e3d27 Reviewed-on: https://go-review.googlesource.com/c/go/+/707595 LUCI-TryBot-Result: Go LUCI Reviewed-by: Cherry Mui Reviewed-by: Carlos Amedee Auto-Submit: Ian Lance Taylor --- src/cmd/link/internal/ld/symtab.go | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/cmd/link/internal/ld/symtab.go b/src/cmd/link/internal/ld/symtab.go index 759262286d39d8..2c999ccc4e3a19 100644 --- a/src/cmd/link/internal/ld/symtab.go +++ b/src/cmd/link/internal/ld/symtab.go @@ -645,7 +645,7 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind { sliceSym(pcln.funcnametab) // The cutab slice - sliceSym(pcln.cutab) + slice(pcln.cutab, uint64(ldr.SymSize(pcln.cutab))/4) // The filetab slice sliceSym(pcln.filetab) @@ -654,7 +654,7 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind { sliceSym(pcln.pctab) // The pclntab slice - slice(pcln.pclntab, uint64(ldr.SymSize(pcln.pclntab))) + sliceSym(pcln.pclntab) // The ftab slice slice(pcln.pclntab, uint64(pcln.nfunc+1)) From 047c2ab841e2d2233d0bef420d1b5ecb545a380a Mon Sep 17 00:00:00 2001 From: Cherry Mui Date: Fri, 26 Sep 2025 09:45:08 -0400 Subject: [PATCH 006/229] cmd/link: don't pass -Wl,-S on Solaris Solaris linker's -S has a different meaning. Fixes #75637. Change-Id: I51e641d5bc6d7f64ab5aa280090c70ec787a1fbf Reviewed-on: https://go-review.googlesource.com/c/go/+/707096 LUCI-TryBot-Result: Go LUCI Reviewed-by: David Chase --- src/cmd/link/dwarf_test.go | 2 +- src/cmd/link/internal/ld/lib.go | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/src/cmd/link/dwarf_test.go b/src/cmd/link/dwarf_test.go index 4fce358e602de5..56a076002a92d4 100644 --- a/src/cmd/link/dwarf_test.go +++ b/src/cmd/link/dwarf_test.go @@ -386,7 +386,7 @@ func TestFlagW(t *testing.T) { {"-s", false}, // -s implies -w {"-s -w=0", true}, // -w=0 negates the implied -w } - if testenv.HasCGO() { + if testenv.HasCGO() && runtime.GOOS != "solaris" { // Solaris linker doesn't support the -S flag tests = append(tests, testCase{"-w -linkmode=external", false}, testCase{"-s -linkmode=external", false}, diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go index 8d2763bb57f31a..c7596d535e0ee5 100644 --- a/src/cmd/link/internal/ld/lib.go +++ b/src/cmd/link/internal/ld/lib.go @@ -1452,7 +1452,7 @@ func (ctxt *Link) hostlink() { argv = append(argv, "-s") } } else if *FlagW { - if !ctxt.IsAIX() { // The AIX linker's -S has different meaning + if !ctxt.IsAIX() && !ctxt.IsSolaris() { // The AIX and Solaris linkers' -S has different meaning argv = append(argv, "-Wl,-S") // suppress debugging symbols } } From 4e9006a716533fe1c7ee08df02dfc73078f7dc19 Mon Sep 17 00:00:00 2001 From: Roland Shoemaker Date: Mon, 29 Sep 2025 10:11:56 -0700 Subject: [PATCH 007/229] crypto/tls: quote protocols in ALPN error message Quote the protocols sent by the client when returning the ALPN negotiation error message. Fixes CVE-2025-58189 Fixes #75652 Change-Id: Ie7b3a1ed0b6efcc1705b71f0f1e8417126661330 Reviewed-on: https://go-review.googlesource.com/c/go/+/707776 Auto-Submit: Roland Shoemaker Reviewed-by: Neal Patel Reviewed-by: Nicholas Husin Auto-Submit: Nicholas Husin Reviewed-by: Nicholas Husin TryBot-Bypass: Roland Shoemaker Reviewed-by: Daniel McCarney --- src/crypto/tls/handshake_server.go | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/crypto/tls/handshake_server.go b/src/crypto/tls/handshake_server.go index 1e0b5f06672d15..088c66fadb2a44 100644 --- a/src/crypto/tls/handshake_server.go +++ b/src/crypto/tls/handshake_server.go @@ -357,7 +357,7 @@ func negotiateALPN(serverProtos, clientProtos []string, quic bool) (string, erro if http11fallback { return "", nil } - return "", fmt.Errorf("tls: client requested unsupported application protocols (%s)", clientProtos) + return "", fmt.Errorf("tls: client requested unsupported application protocols (%q)", clientProtos) } // supportsECDHE returns whether ECDHE key exchanges can be used with this From 4b7773356515c178f0af859b952b4b3a78f0813d Mon Sep 17 00:00:00 2001 From: qmuntal Date: Mon, 29 Sep 2025 08:37:35 +0200 Subject: [PATCH 008/229] internal/syscall/windows: regenerate GetFileSizeEx GetFileSizeEx was generated before mkwinsyscall was updated to use SyscallN. Regenerate to use the new style. Fixes #75642 Change-Id: Ia473a167633b67fb75b5762d693848ecee425a7e Reviewed-on: https://go-review.googlesource.com/c/go/+/707615 Reviewed-by: Roland Shoemaker Auto-Submit: Dmitri Shuralyov Reviewed-by: Dmitri Shuralyov LUCI-TryBot-Result: Go LUCI Reviewed-by: Dmitri Shuralyov --- src/internal/syscall/windows/zsyscall_windows.go | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/internal/syscall/windows/zsyscall_windows.go b/src/internal/syscall/windows/zsyscall_windows.go index fb8bc80629a626..70c4d76dff0d0f 100644 --- a/src/internal/syscall/windows/zsyscall_windows.go +++ b/src/internal/syscall/windows/zsyscall_windows.go @@ -328,7 +328,7 @@ func GetFileInformationByHandleEx(handle syscall.Handle, class uint32, info *byt } func GetFileSizeEx(handle syscall.Handle, size *int64) (err error) { - r1, _, e1 := syscall.Syscall(procGetFileSizeEx.Addr(), 2, uintptr(handle), uintptr(unsafe.Pointer(size)), 0) + r1, _, e1 := syscall.SyscallN(procGetFileSizeEx.Addr(), uintptr(handle), uintptr(unsafe.Pointer(size))) if r1 == 0 { err = errnoErr(e1) } From eaf2345256613dfbda7e8e69e5f845c4209246c6 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Mon, 22 Sep 2025 15:48:36 +0200 Subject: [PATCH 009/229] cmd/link: use a .def file to mark exported symbols on Windows Binutils defaults to exporting all symbols when building a Windows DLL. To avoid that we were marking symbols with __declspec(dllexport) in the cgo-generated headers, which instructs ld to export only those symbols. However, that approach makes the headers hard to reuse when importing the resulting DLL into other projects, as imported symbols should be marked with __declspec(dllimport). A better approach is to generate a .def file listing the symbols to export, which gets the same effect without having to modify the headers. Updates #30674 Fixes #56994 Change-Id: I22bd0aa079e2be4ae43b13d893f6b804eaeddabf Reviewed-on: https://go-review.googlesource.com/c/go/+/705776 Reviewed-by: Michael Knyszek Reviewed-by: Junyang Shao Reviewed-by: Than McIntosh Reviewed-by: Cherry Mui LUCI-TryBot-Result: Go LUCI --- .../cgo/internal/testcshared/cshared_test.go | 75 ++++++++----------- src/cmd/cgo/out.go | 6 +- src/cmd/link/internal/ld/lib.go | 9 ++- src/cmd/link/internal/ld/pe.go | 44 +++++++++++ src/cmd/link/internal/ld/xcoff.go | 5 +- src/cmd/link/internal/loader/loader.go | 13 ++++ src/runtime/cgo/gcc_libinit_windows.c | 9 --- src/runtime/cgo/windows.go | 22 ++++++ 8 files changed, 118 insertions(+), 65 deletions(-) create mode 100644 src/runtime/cgo/windows.go diff --git a/src/cmd/cgo/internal/testcshared/cshared_test.go b/src/cmd/cgo/internal/testcshared/cshared_test.go index f1c30f8f9a2b2a..2ce705adba44f3 100644 --- a/src/cmd/cgo/internal/testcshared/cshared_test.go +++ b/src/cmd/cgo/internal/testcshared/cshared_test.go @@ -8,6 +8,7 @@ import ( "bufio" "bytes" "cmd/cgo/internal/cgotest" + "cmp" "debug/elf" "debug/pe" "encoding/binary" @@ -272,7 +273,7 @@ func createHeaders() error { // which results in the linkers output implib getting overwritten at each step. So instead build the // import library the traditional way, using a def file. err = os.WriteFile("libgo.def", - []byte("LIBRARY libgo.dll\nEXPORTS\n\tDidInitRun\n\tDidMainRun\n\tDivu\n\tFromPkg\n\t_cgo_dummy_export\n"), + []byte("LIBRARY libgo.dll\nEXPORTS\n\tDidInitRun\n\tDidMainRun\n\tDivu\n\tFromPkg\n"), 0644) if err != nil { return fmt.Errorf("unable to write def file: %v", err) @@ -375,9 +376,23 @@ func TestExportedSymbols(t *testing.T) { } } -func checkNumberOfExportedFunctionsWindows(t *testing.T, prog string, exportedFunctions int, wantAll bool) { +func checkNumberOfExportedSymbolsWindows(t *testing.T, exportedSymbols int, wantAll bool) { + t.Parallel() tmpdir := t.TempDir() + prog := ` +package main +import "C" +func main() {} +` + + for i := range exportedSymbols { + prog += fmt.Sprintf(` +//export GoFunc%d +func GoFunc%d() {} +`, i, i) + } + srcfile := filepath.Join(tmpdir, "test.go") objfile := filepath.Join(tmpdir, "test.dll") if err := os.WriteFile(srcfile, []byte(prog), 0666); err != nil { @@ -443,18 +458,19 @@ func checkNumberOfExportedFunctionsWindows(t *testing.T, prog string, exportedFu t.Fatalf("binary.Read failed: %v", err) } - // Only the two exported functions and _cgo_dummy_export should be exported. + exportedSymbols = cmp.Or(exportedSymbols, 1) // _cgo_stub_export is exported if there are no other symbols exported + // NumberOfNames is the number of functions exported with a unique name. // NumberOfFunctions can be higher than that because it also counts // functions exported only by ordinal, a unique number asigned by the linker, // and linkers might add an unknown number of their own ordinal-only functions. if wantAll { - if e.NumberOfNames <= uint32(exportedFunctions) { - t.Errorf("got %d exported names, want > %d", e.NumberOfNames, exportedFunctions) + if e.NumberOfNames <= uint32(exportedSymbols) { + t.Errorf("got %d exported names, want > %d", e.NumberOfNames, exportedSymbols) } } else { - if e.NumberOfNames > uint32(exportedFunctions) { - t.Errorf("got %d exported names, want <= %d", e.NumberOfNames, exportedFunctions) + if e.NumberOfNames != uint32(exportedSymbols) { + t.Errorf("got %d exported names, want %d", e.NumberOfNames, exportedSymbols) } } } @@ -470,43 +486,14 @@ func TestNumberOfExportedFunctions(t *testing.T) { t.Parallel() - const prog0 = ` -package main - -import "C" - -func main() { -} -` - - const prog2 = ` -package main - -import "C" - -//export GoFunc -func GoFunc() { - println(42) -} - -//export GoFunc2 -func GoFunc2() { - println(24) -} - -func main() { -} -` - // All programs export _cgo_dummy_export, so add 1 to the expected counts. - t.Run("OnlyExported/0", func(t *testing.T) { - checkNumberOfExportedFunctionsWindows(t, prog0, 0+1, false) - }) - t.Run("OnlyExported/2", func(t *testing.T) { - checkNumberOfExportedFunctionsWindows(t, prog2, 2+1, false) - }) - t.Run("All", func(t *testing.T) { - checkNumberOfExportedFunctionsWindows(t, prog2, 2+1, true) - }) + for i := range 3 { + t.Run(fmt.Sprintf("OnlyExported/%d", i), func(t *testing.T) { + checkNumberOfExportedSymbolsWindows(t, i, false) + }) + t.Run(fmt.Sprintf("All/%d", i), func(t *testing.T) { + checkNumberOfExportedSymbolsWindows(t, i, true) + }) + } } // test1: shared library can be dynamically loaded and exported symbols are accessible. diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go index dfa54e41d33399..622d35ac7b3bab 100644 --- a/src/cmd/cgo/out.go +++ b/src/cmd/cgo/out.go @@ -1005,12 +1005,8 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) { } // Build the wrapper function compiled by gcc. - gccExport := "" - if goos == "windows" { - gccExport = "__declspec(dllexport) " - } var s strings.Builder - fmt.Fprintf(&s, "%s%s %s(", gccExport, gccResult, exp.ExpName) + fmt.Fprintf(&s, "%s %s(", gccResult, exp.ExpName) if fn.Recv != nil { s.WriteString(p.cgoType(fn.Recv.List[0].Type).C.String()) s.WriteString(" recv") diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go index c7596d535e0ee5..79d3d37835e9ad 100644 --- a/src/cmd/link/internal/ld/lib.go +++ b/src/cmd/link/internal/ld/lib.go @@ -1772,7 +1772,8 @@ func (ctxt *Link) hostlink() { } // Force global symbols to be exported for dlopen, etc. - if ctxt.IsELF { + switch { + case ctxt.IsELF: if ctxt.DynlinkingGo() || ctxt.BuildMode == BuildModeCShared || !linkerFlagSupported(ctxt.Arch, argv[0], altLinker, "-Wl,--export-dynamic-symbol=main") { argv = append(argv, "-rdynamic") } else { @@ -1783,10 +1784,12 @@ func (ctxt *Link) hostlink() { sort.Strings(exports) argv = append(argv, exports...) } - } - if ctxt.HeadType == objabi.Haix { + case ctxt.IsAIX(): fileName := xcoffCreateExportFile(ctxt) argv = append(argv, "-Wl,-bE:"+fileName) + case ctxt.IsWindows() && !slices.Contains(flagExtldflags, "-Wl,--export-all-symbols"): + fileName := peCreateExportFile(ctxt, filepath.Base(outopt)) + argv = append(argv, fileName) } const unusedArguments = "-Qunused-arguments" diff --git a/src/cmd/link/internal/ld/pe.go b/src/cmd/link/internal/ld/pe.go index 5219a98dd47cf4..0f0650e5e149e3 100644 --- a/src/cmd/link/internal/ld/pe.go +++ b/src/cmd/link/internal/ld/pe.go @@ -8,6 +8,7 @@ package ld import ( + "bytes" "cmd/internal/objabi" "cmd/internal/sys" "cmd/link/internal/loader" @@ -17,6 +18,8 @@ import ( "fmt" "internal/buildcfg" "math" + "os" + "path/filepath" "slices" "sort" "strconv" @@ -1748,3 +1751,44 @@ func asmbPe(ctxt *Link) { pewrite(ctxt) } + +// peCreateExportFile creates a file with exported symbols for Windows .def files. +// ld will export all symbols, even those not marked for export, unless a .def file is provided. +func peCreateExportFile(ctxt *Link, libName string) (fname string) { + fname = filepath.Join(*flagTmpdir, "export_file.def") + var buf bytes.Buffer + + fmt.Fprintf(&buf, "LIBRARY %s\n", libName) + buf.WriteString("EXPORTS\n") + + ldr := ctxt.loader + var exports []string + for s := range ldr.ForAllCgoExportStatic() { + extname := ldr.SymExtname(s) + if !strings.HasPrefix(extname, "_cgoexp_") { + continue + } + if ldr.IsFileLocal(s) { + continue // Only export non-static symbols + } + // Retrieve the name of the initial symbol + // exported by cgo. + // The corresponding Go symbol is: + // _cgoexp_hashcode_symname. + name := strings.SplitN(extname, "_", 4)[3] + exports = append(exports, name) + } + if len(exports) == 0 { + // See runtime/cgo/windows.go for details. + exports = append(exports, "_cgo_stub_export") + } + sort.Strings(exports) + buf.WriteString(strings.Join(exports, "\n")) + + err := os.WriteFile(fname, buf.Bytes(), 0666) + if err != nil { + Errorf("WriteFile %s failed: %v", fname, err) + } + + return fname +} diff --git a/src/cmd/link/internal/ld/xcoff.go b/src/cmd/link/internal/ld/xcoff.go index 1bce2cf9b6124d..da728e25455618 100644 --- a/src/cmd/link/internal/ld/xcoff.go +++ b/src/cmd/link/internal/ld/xcoff.go @@ -1779,10 +1779,7 @@ func xcoffCreateExportFile(ctxt *Link) (fname string) { var buf bytes.Buffer ldr := ctxt.loader - for s, nsym := loader.Sym(1), loader.Sym(ldr.NSym()); s < nsym; s++ { - if !ldr.AttrCgoExport(s) { - continue - } + for s := range ldr.ForAllCgoExportStatic() { extname := ldr.SymExtname(s) if !strings.HasPrefix(extname, "._cgoexp_") { continue diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go index 9f3ea3e553dd7c..103dad03001263 100644 --- a/src/cmd/link/internal/loader/loader.go +++ b/src/cmd/link/internal/loader/loader.go @@ -16,6 +16,7 @@ import ( "fmt" "internal/abi" "io" + "iter" "log" "math/bits" "os" @@ -1109,6 +1110,18 @@ func (l *Loader) SetAttrCgoExportStatic(i Sym, v bool) { } } +// ForAllCgoExportStatic returns an iterator over all symbols +// marked with the "cgo_export_static" compiler directive. +func (l *Loader) ForAllCgoExportStatic() iter.Seq[Sym] { + return func(yield func(Sym) bool) { + for s := range l.attrCgoExportStatic { + if !yield(s) { + break + } + } + } +} + // IsGeneratedSym returns true if a symbol's been previously marked as a // generator symbol through the SetIsGeneratedSym. The functions for generator // symbols are kept in the Link context. diff --git a/src/runtime/cgo/gcc_libinit_windows.c b/src/runtime/cgo/gcc_libinit_windows.c index 926f9168434638..7e7ff3e667266f 100644 --- a/src/runtime/cgo/gcc_libinit_windows.c +++ b/src/runtime/cgo/gcc_libinit_windows.c @@ -15,15 +15,6 @@ #include "libcgo.h" #include "libcgo_windows.h" -// Ensure there's one symbol marked __declspec(dllexport). -// If there are no exported symbols, the unfortunate behavior of -// the binutils linker is to also strip the relocations table, -// resulting in non-PIE binary. The other option is the -// --export-all-symbols flag, but we don't need to export all symbols -// and this may overflow the export table (#40795). -// See https://sourceware.org/bugzilla/show_bug.cgi?id=19011 -__declspec(dllexport) int _cgo_dummy_export; - static volatile LONG runtime_init_once_gate = 0; static volatile LONG runtime_init_once_done = 0; diff --git a/src/runtime/cgo/windows.go b/src/runtime/cgo/windows.go new file mode 100644 index 00000000000000..7ba61753dffda2 --- /dev/null +++ b/src/runtime/cgo/windows.go @@ -0,0 +1,22 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +//go:build windows + +package cgo + +import _ "unsafe" // for go:linkname + +// _cgo_stub_export is only used to ensure there's at least one symbol +// in the .def file passed to the external linker. +// If there are no exported symbols, the unfortunate behavior of +// the binutils linker is to also strip the relocations table, +// resulting in non-PIE binary. The other option is the +// --export-all-symbols flag, but we don't need to export all symbols +// and this may overflow the export table (#40795). +// See https://sourceware.org/bugzilla/show_bug.cgi?id=19011 +// +//go:cgo_export_static _cgo_stub_export +//go:linkname _cgo_stub_export _cgo_stub_export +var _cgo_stub_export uintptr From 690fc2fb05e720850a474c72bf3a8a9a6638cef7 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Tue, 16 Sep 2025 10:25:58 +0200 Subject: [PATCH 010/229] internal/poll: remove buf field from operation WSASend and WSARecv functions capture the WSABuf structure before returning, so there is no need to keep a copy of it in the operation structure. Write and Read functions don't need it, they can operate directly on the byte slice. To be on the safe side, pin the input byte slice so that stack-allocated slices don't get moved while overlapped I/O is in progress. Cq-Include-Trybots: luci.golang.try:gotip-windows-amd64-longtest,gotip-windows-amd64-race Change-Id: I474bed94e11acafa0bdd8392b5dcf8993d8e1ed5 Reviewed-on: https://go-review.googlesource.com/c/go/+/704155 Reviewed-by: Junyang Shao LUCI-TryBot-Result: Go LUCI Reviewed-by: Damien Neil --- src/internal/poll/fd_windows.go | 170 ++++++++++++++++++-------------- src/net/tcpsock_test.go | 7 +- 2 files changed, 100 insertions(+), 77 deletions(-) diff --git a/src/internal/poll/fd_windows.go b/src/internal/poll/fd_windows.go index dd9845d1b223c3..9323e49eb745d7 100644 --- a/src/internal/poll/fd_windows.go +++ b/src/internal/poll/fd_windows.go @@ -9,6 +9,7 @@ import ( "internal/race" "internal/syscall/windows" "io" + "runtime" "sync" "sync/atomic" "syscall" @@ -75,9 +76,6 @@ type operation struct { // fields used by runtime.netpoll runtimeCtx uintptr mode int32 - - // fields used only by net package - buf syscall.WSABuf } func (o *operation) setEvent() { @@ -107,9 +105,8 @@ func (fd *FD) overlapped(o *operation) *syscall.Overlapped { return &o.o } -func (o *operation) InitBuf(buf []byte) { - o.buf.Len = uint32(len(buf)) - o.buf.Buf = unsafe.SliceData(buf) +func newWsaBuf(b []byte) *syscall.WSABuf { + return &syscall.WSABuf{Buf: unsafe.SliceData(b), Len: uint32(len(b))} } var wsaBufsPool = sync.Pool{ @@ -362,6 +359,9 @@ type FD struct { isBlocking bool disassociated atomic.Bool + + readPinner runtime.Pinner + writePinner runtime.Pinner } // setOffset sets the offset fields of the overlapped object @@ -537,6 +537,11 @@ func (fd *FD) Read(buf []byte) (int, error) { defer fd.readUnlock() } + if len(buf) > 0 && !fd.isBlocking { + fd.readPinner.Pin(&buf[0]) + defer fd.readPinner.Unpin() + } + if len(buf) > maxRW { buf = buf[:maxRW] } @@ -547,10 +552,8 @@ func (fd *FD) Read(buf []byte) (int, error) { case kindConsole: n, err = fd.readConsole(buf) case kindFile, kindPipe: - o := &fd.rop - o.InitBuf(buf) - n, err = fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = syscall.ReadFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &qty, fd.overlapped(o)) + n, err = fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + err = syscall.ReadFile(fd.Sysfd, buf, &qty, fd.overlapped(o)) return qty, err }) fd.addOffset(n) @@ -564,11 +567,9 @@ func (fd *FD) Read(buf []byte) (int, error) { } } case kindNet: - o := &fd.rop - o.InitBuf(buf) - n, err = fd.execIO(o, func(o *operation) (qty uint32, err error) { + n, err = fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { var flags uint32 - err = syscall.WSARecv(fd.Sysfd, &o.buf, 1, &qty, &flags, &o.o, nil) + err = syscall.WSARecv(fd.Sysfd, newWsaBuf(buf), 1, &qty, &flags, &o.o, nil) return qty, err }) if race.Enabled { @@ -656,7 +657,7 @@ func (fd *FD) readConsole(b []byte) (int, error) { } // Pread emulates the Unix pread system call. -func (fd *FD) Pread(b []byte, off int64) (int, error) { +func (fd *FD) Pread(buf []byte, off int64) (int, error) { if fd.kind == kindPipe { // Pread does not work with pipes return 0, syscall.ESPIPE @@ -667,8 +668,13 @@ func (fd *FD) Pread(b []byte, off int64) (int, error) { } defer fd.readWriteUnlock() - if len(b) > maxRW { - b = b[:maxRW] + if len(buf) > 0 && !fd.isBlocking { + fd.readPinner.Pin(&buf[0]) + defer fd.readPinner.Unpin() + } + + if len(buf) > maxRW { + buf = buf[:maxRW] } if fd.isBlocking { @@ -687,17 +693,15 @@ func (fd *FD) Pread(b []byte, off int64) (int, error) { curoffset := fd.offset defer fd.setOffset(curoffset) } - o := &fd.rop - o.InitBuf(b) fd.setOffset(off) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = syscall.ReadFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &qty, &o.o) + n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + err = syscall.ReadFile(fd.Sysfd, buf, &qty, &o.o) return qty, err }) if err == syscall.ERROR_HANDLE_EOF { err = io.EOF } - if len(b) != 0 { + if len(buf) != 0 { err = fd.eofError(n, err) } return n, err @@ -715,14 +719,18 @@ func (fd *FD) ReadFrom(buf []byte) (int, syscall.Sockaddr, error) { return 0, nil, err } defer fd.readUnlock() - o := &fd.rop - o.InitBuf(buf) + + if !fd.isBlocking { + fd.readPinner.Pin(&buf[0]) + defer fd.readPinner.Unpin() + } + rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { rsan := int32(unsafe.Sizeof(*rsa)) var flags uint32 - err = syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &qty, &flags, rsa, &rsan, &o.o, nil) + err = syscall.WSARecvFrom(fd.Sysfd, newWsaBuf(buf), 1, &qty, &flags, rsa, &rsan, &o.o, nil) return qty, err }) err = fd.eofError(n, err) @@ -745,14 +753,18 @@ func (fd *FD) ReadFromInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error) return 0, err } defer fd.readUnlock() - o := &fd.rop - o.InitBuf(buf) + + if !fd.isBlocking { + fd.readPinner.Pin(&buf[0]) + defer fd.readPinner.Unpin() + } + rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { rsan := int32(unsafe.Sizeof(*rsa)) var flags uint32 - err = syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &qty, &flags, rsa, &rsan, &o.o, nil) + err = syscall.WSARecvFrom(fd.Sysfd, newWsaBuf(buf), 1, &qty, &flags, rsa, &rsan, &o.o, nil) return qty, err }) err = fd.eofError(n, err) @@ -775,14 +787,18 @@ func (fd *FD) ReadFromInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error) return 0, err } defer fd.readUnlock() - o := &fd.rop - o.InitBuf(buf) + + if !fd.isBlocking { + fd.readPinner.Pin(&buf[0]) + defer fd.readPinner.Unpin() + } + rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { rsan := int32(unsafe.Sizeof(*rsa)) var flags uint32 - err = syscall.WSARecvFrom(fd.Sysfd, &o.buf, 1, &qty, &flags, rsa, &rsan, &o.o, nil) + err = syscall.WSARecvFrom(fd.Sysfd, newWsaBuf(buf), 1, &qty, &flags, rsa, &rsan, &o.o, nil) return qty, err }) err = fd.eofError(n, err) @@ -807,6 +823,11 @@ func (fd *FD) Write(buf []byte) (int, error) { defer fd.writeUnlock() } + if len(buf) > 0 && !fd.isBlocking { + fd.writePinner.Pin(&buf[0]) + defer fd.writePinner.Unpin() + } + var ntotal int for { max := len(buf) @@ -820,10 +841,8 @@ func (fd *FD) Write(buf []byte) (int, error) { case kindConsole: n, err = fd.writeConsole(b) case kindPipe, kindFile: - o := &fd.wop - o.InitBuf(b) - n, err = fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = syscall.WriteFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &qty, fd.overlapped(o)) + n, err = fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = syscall.WriteFile(fd.Sysfd, b, &qty, fd.overlapped(o)) return qty, err }) fd.addOffset(n) @@ -831,10 +850,8 @@ func (fd *FD) Write(buf []byte) (int, error) { if race.Enabled { race.ReleaseMerge(unsafe.Pointer(&ioSync)) } - o := &fd.wop - o.InitBuf(b) - n, err = fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = syscall.WSASend(fd.Sysfd, &o.buf, 1, &qty, 0, &o.o, nil) + n, err = fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = syscall.WSASend(fd.Sysfd, newWsaBuf(b), 1, &qty, 0, &o.o, nil) return qty, err }) } @@ -903,6 +920,11 @@ func (fd *FD) Pwrite(buf []byte, off int64) (int, error) { } defer fd.readWriteUnlock() + if len(buf) > 0 && !fd.isBlocking { + fd.writePinner.Pin(&buf[0]) + defer fd.writePinner.Unpin() + } + if fd.isBlocking { curoffset, err := syscall.Seek(fd.Sysfd, 0, io.SeekCurrent) if err != nil { @@ -926,12 +948,9 @@ func (fd *FD) Pwrite(buf []byte, off int64) (int, error) { if max-ntotal > maxRW { max = ntotal + maxRW } - b := buf[ntotal:max] - o := &fd.wop - o.InitBuf(b) fd.setOffset(off + int64(ntotal)) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = syscall.WriteFile(fd.Sysfd, unsafe.Slice(o.buf.Buf, o.buf.Len), &qty, &o.o) + n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = syscall.WriteFile(fd.Sysfd, buf[ntotal:max], &qty, &o.o) return qty, err }) if n > 0 { @@ -978,25 +997,26 @@ func (fd *FD) WriteTo(buf []byte, sa syscall.Sockaddr) (int, error) { if len(buf) == 0 { // handle zero-byte payload - o := &fd.wop - o.InitBuf(buf) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = syscall.WSASendto(fd.Sysfd, &o.buf, 1, &qty, 0, sa, &o.o, nil) + n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = syscall.WSASendto(fd.Sysfd, &syscall.WSABuf{}, 1, &qty, 0, sa, &o.o, nil) return qty, err }) return n, err } + if !fd.isBlocking { + fd.writePinner.Pin(&buf[0]) + defer fd.writePinner.Unpin() + } + ntotal := 0 for len(buf) > 0 { b := buf if len(b) > maxRW { b = b[:maxRW] } - o := &fd.wop - o.InitBuf(b) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = syscall.WSASendto(fd.Sysfd, &o.buf, 1, &qty, 0, sa, &o.o, nil) + n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = syscall.WSASendto(fd.Sysfd, newWsaBuf(b), 1, &qty, 0, sa, &o.o, nil) return qty, err }) ntotal += int(n) @@ -1017,25 +1037,26 @@ func (fd *FD) WriteToInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error) if len(buf) == 0 { // handle zero-byte payload - o := &fd.wop - o.InitBuf(buf) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = windows.WSASendtoInet4(fd.Sysfd, &o.buf, 1, &qty, 0, sa4, &o.o, nil) + n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = windows.WSASendtoInet4(fd.Sysfd, &syscall.WSABuf{}, 1, &qty, 0, sa4, &o.o, nil) return qty, err }) return n, err } + if !fd.isBlocking { + fd.writePinner.Pin(&buf[0]) + defer fd.writePinner.Unpin() + } + ntotal := 0 for len(buf) > 0 { b := buf if len(b) > maxRW { b = b[:maxRW] } - o := &fd.wop - o.InitBuf(b) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = windows.WSASendtoInet4(fd.Sysfd, &o.buf, 1, &qty, 0, sa4, &o.o, nil) + n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = windows.WSASendtoInet4(fd.Sysfd, newWsaBuf(b), 1, &qty, 0, sa4, &o.o, nil) return qty, err }) ntotal += int(n) @@ -1056,25 +1077,26 @@ func (fd *FD) WriteToInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error) if len(buf) == 0 { // handle zero-byte payload - o := &fd.wop - o.InitBuf(buf) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = windows.WSASendtoInet6(fd.Sysfd, &o.buf, 1, &qty, 0, sa6, &o.o, nil) + n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = windows.WSASendtoInet6(fd.Sysfd, &syscall.WSABuf{}, 1, &qty, 0, sa6, &o.o, nil) return qty, err }) return n, err } + if !fd.isBlocking { + fd.writePinner.Pin(&buf[0]) + defer fd.writePinner.Unpin() + } + ntotal := 0 for len(buf) > 0 { b := buf if len(b) > maxRW { b = b[:maxRW] } - o := &fd.wop - o.InitBuf(b) - n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { - err = windows.WSASendtoInet6(fd.Sysfd, &o.buf, 1, &qty, 0, sa6, &o.o, nil) + n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + err = windows.WSASendtoInet6(fd.Sysfd, newWsaBuf(b), 1, &qty, 0, sa6, &o.o, nil) return qty, err }) ntotal += int(n) @@ -1264,14 +1286,12 @@ func (fd *FD) RawRead(f func(uintptr) bool) error { // Use a zero-byte read as a way to get notified when this // socket is readable. h/t https://stackoverflow.com/a/42019668/332798 - o := &fd.rop - o.InitBuf(nil) - _, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { + _, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { var flags uint32 if !fd.IsStream { flags |= windows.MSG_PEEK } - err = syscall.WSARecv(fd.Sysfd, &o.buf, 1, &qty, &flags, &o.o, nil) + err = syscall.WSARecv(fd.Sysfd, &syscall.WSABuf{}, 1, &qty, &flags, &o.o, nil) return qty, err }) if err == windows.WSAEMSGSIZE { diff --git a/src/net/tcpsock_test.go b/src/net/tcpsock_test.go index 9ed49a925b4b39..085989c7499b60 100644 --- a/src/net/tcpsock_test.go +++ b/src/net/tcpsock_test.go @@ -475,6 +475,9 @@ func TestTCPReadWriteAllocs(t *testing.T) { t.Skipf("not supported on %s", runtime.GOOS) } + // Optimizations are required to remove the allocs. + testenv.SkipIfOptimizationOff(t) + ln, err := Listen("tcp", "127.0.0.1:0") if err != nil { t.Fatal(err) @@ -509,7 +512,7 @@ func TestTCPReadWriteAllocs(t *testing.T) { } }) if allocs > 0 { - t.Fatalf("got %v; want 0", allocs) + t.Errorf("got %v; want 0", allocs) } var bufwrt [128]byte @@ -531,7 +534,7 @@ func TestTCPReadWriteAllocs(t *testing.T) { } }) if allocs > 0 { - t.Fatalf("got %v; want 0", allocs) + t.Errorf("got %v; want 0", allocs) } } From db3cb3fd9a09355a2f239dcb28c480b18bfa7f5e Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Sun, 28 Sep 2025 21:22:09 -0700 Subject: [PATCH 011/229] runtime: correct reference to getStackMap in comment Change-Id: I9b1fa390434dbda7d49a36b0114c68f942c11d3f Reviewed-on: https://go-review.googlesource.com/c/go/+/707575 Auto-Submit: Ian Lance Taylor Reviewed-by: Michael Knyszek Reviewed-by: Carlos Amedee LUCI-TryBot-Result: Go LUCI --- src/runtime/traceback.go | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go index 949d48c79a6df5..53f41bca0b11ff 100644 --- a/src/runtime/traceback.go +++ b/src/runtime/traceback.go @@ -429,7 +429,7 @@ func (u *unwinder) resolveInternal(innermost, isSyscall bool) { // gp._defer for a defer corresponding to this function, but that // is hard to do with defer records on the stack during a stack copy.) // Note: the +1 is to offset the -1 that - // stack.go:getStackMap does to back up a return + // (*stkframe).getStackMap does to back up a return // address make sure the pc is in the CALL instruction. } else { frame.continpc = 0 From db4fade7599d49dc85a7ef670499be0ccd62c58e Mon Sep 17 00:00:00 2001 From: Filippo Valsorda Date: Mon, 22 Sep 2025 14:05:23 +0200 Subject: [PATCH 012/229] crypto/internal/fips140/mlkem: make CAST conditional MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit It taks north of 130µs on my machine, which is enough to be worth shaving off at init time. Change-Id: I6a6a696463de228bc3e7b9ca10c12ddbaabdf384 Reviewed-on: https://go-review.googlesource.com/c/go/+/707695 Auto-Submit: Filippo Valsorda Reviewed-by: Daniel McCarney Reviewed-by: Roland Shoemaker LUCI-TryBot-Result: Go LUCI Reviewed-by: Carlos Amedee --- src/crypto/internal/fips140/mlkem/cast.go | 13 ++++++------ .../internal/fips140/mlkem/mlkem1024.go | 5 +++++ src/crypto/internal/fips140/mlkem/mlkem768.go | 5 +++++ src/crypto/internal/fips140test/cast_test.go | 21 ++++++++++++++++--- 4 files changed, 34 insertions(+), 10 deletions(-) diff --git a/src/crypto/internal/fips140/mlkem/cast.go b/src/crypto/internal/fips140/mlkem/cast.go index a432d1fdab0e2b..ea089c1b76c0c0 100644 --- a/src/crypto/internal/fips140/mlkem/cast.go +++ b/src/crypto/internal/fips140/mlkem/cast.go @@ -9,9 +9,10 @@ import ( "crypto/internal/fips140" _ "crypto/internal/fips140/check" "errors" + "sync" ) -func init() { +var fipsSelfTest = sync.OnceFunc(func() { fips140.CAST("ML-KEM-768", func() error { var d = &[32]byte{ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, @@ -40,14 +41,12 @@ func init() { dk := &DecapsulationKey768{} kemKeyGen(dk, d, z) ek := dk.EncapsulationKey() - Ke, c := ek.EncapsulateInternal(m) - Kd, err := dk.Decapsulate(c) - if err != nil { - return err - } + var cc [CiphertextSize768]byte + Ke, _ := kemEncaps(&cc, ek, m) + Kd := kemDecaps(dk, &cc) if !bytes.Equal(Ke, K) || !bytes.Equal(Kd, K) { return errors.New("unexpected result") } return nil }) -} +}) diff --git a/src/crypto/internal/fips140/mlkem/mlkem1024.go b/src/crypto/internal/fips140/mlkem/mlkem1024.go index 1419cf20fa9c67..edde161422cb6f 100644 --- a/src/crypto/internal/fips140/mlkem/mlkem1024.go +++ b/src/crypto/internal/fips140/mlkem/mlkem1024.go @@ -113,6 +113,7 @@ func GenerateKey1024() (*DecapsulationKey1024, error) { } func generateKey1024(dk *DecapsulationKey1024) (*DecapsulationKey1024, error) { + fipsSelfTest() var d [32]byte drbg.Read(d[:]) var z [32]byte @@ -126,6 +127,7 @@ func generateKey1024(dk *DecapsulationKey1024) (*DecapsulationKey1024, error) { // GenerateKeyInternal1024 is a derandomized version of GenerateKey1024, // exclusively for use in tests. func GenerateKeyInternal1024(d, z *[32]byte) *DecapsulationKey1024 { + fipsSelfTest() dk := &DecapsulationKey1024{} kemKeyGen1024(dk, d, z) return dk @@ -278,6 +280,7 @@ func (ek *EncapsulationKey1024) Encapsulate() (sharedKey, ciphertext []byte) { } func (ek *EncapsulationKey1024) encapsulate(cc *[CiphertextSize1024]byte) (sharedKey, ciphertext []byte) { + fipsSelfTest() var m [messageSize]byte drbg.Read(m[:]) // Note that the modulus check (step 2 of the encapsulation key check from @@ -289,6 +292,7 @@ func (ek *EncapsulationKey1024) encapsulate(cc *[CiphertextSize1024]byte) (share // EncapsulateInternal is a derandomized version of Encapsulate, exclusively for // use in tests. func (ek *EncapsulationKey1024) EncapsulateInternal(m *[32]byte) (sharedKey, ciphertext []byte) { + fipsSelfTest() cc := &[CiphertextSize1024]byte{} return kemEncaps1024(cc, ek, m) } @@ -394,6 +398,7 @@ func pkeEncrypt1024(cc *[CiphertextSize1024]byte, ex *encryptionKey1024, m *[mes // // The shared key must be kept secret. func (dk *DecapsulationKey1024) Decapsulate(ciphertext []byte) (sharedKey []byte, err error) { + fipsSelfTest() if len(ciphertext) != CiphertextSize1024 { return nil, errors.New("mlkem: invalid ciphertext length") } diff --git a/src/crypto/internal/fips140/mlkem/mlkem768.go b/src/crypto/internal/fips140/mlkem/mlkem768.go index 298660e4e977dd..088c2954de6a5c 100644 --- a/src/crypto/internal/fips140/mlkem/mlkem768.go +++ b/src/crypto/internal/fips140/mlkem/mlkem768.go @@ -172,6 +172,7 @@ func GenerateKey768() (*DecapsulationKey768, error) { } func generateKey(dk *DecapsulationKey768) (*DecapsulationKey768, error) { + fipsSelfTest() var d [32]byte drbg.Read(d[:]) var z [32]byte @@ -185,6 +186,7 @@ func generateKey(dk *DecapsulationKey768) (*DecapsulationKey768, error) { // GenerateKeyInternal768 is a derandomized version of GenerateKey768, // exclusively for use in tests. func GenerateKeyInternal768(d, z *[32]byte) *DecapsulationKey768 { + fipsSelfTest() dk := &DecapsulationKey768{} kemKeyGen(dk, d, z) return dk @@ -337,6 +339,7 @@ func (ek *EncapsulationKey768) Encapsulate() (sharedKey, ciphertext []byte) { } func (ek *EncapsulationKey768) encapsulate(cc *[CiphertextSize768]byte) (sharedKey, ciphertext []byte) { + fipsSelfTest() var m [messageSize]byte drbg.Read(m[:]) // Note that the modulus check (step 2 of the encapsulation key check from @@ -348,6 +351,7 @@ func (ek *EncapsulationKey768) encapsulate(cc *[CiphertextSize768]byte) (sharedK // EncapsulateInternal is a derandomized version of Encapsulate, exclusively for // use in tests. func (ek *EncapsulationKey768) EncapsulateInternal(m *[32]byte) (sharedKey, ciphertext []byte) { + fipsSelfTest() cc := &[CiphertextSize768]byte{} return kemEncaps(cc, ek, m) } @@ -453,6 +457,7 @@ func pkeEncrypt(cc *[CiphertextSize768]byte, ex *encryptionKey, m *[messageSize] // // The shared key must be kept secret. func (dk *DecapsulationKey768) Decapsulate(ciphertext []byte) (sharedKey []byte, err error) { + fipsSelfTest() if len(ciphertext) != CiphertextSize768 { return nil, errors.New("mlkem: invalid ciphertext length") } diff --git a/src/crypto/internal/fips140test/cast_test.go b/src/crypto/internal/fips140test/cast_test.go index b043a71f04effa..5bbc964b617b2b 100644 --- a/src/crypto/internal/fips140test/cast_test.go +++ b/src/crypto/internal/fips140test/cast_test.go @@ -48,8 +48,8 @@ var allCASTs = []string{ "HKDF-SHA2-256", "HMAC-SHA2-256", "KAS-ECC-SSC P-256", - "ML-KEM PCT", - "ML-KEM PCT", + "ML-KEM PCT", // -768 + "ML-KEM PCT", // -1024 "ML-KEM-768", "PBKDF2", "RSA sign and verify PCT", @@ -104,29 +104,44 @@ func TestAllCASTs(t *testing.T) { // TestConditionals causes the conditional CASTs and PCTs to be invoked. func TestConditionals(t *testing.T) { - mlkem.GenerateKey768() + // ML-KEM PCT + kMLKEM, err := mlkem.GenerateKey768() + if err != nil { + t.Error(err) + } else { + // ML-KEM-768 + kMLKEM.EncapsulationKey().Encapsulate() + } + // ECDH PCT kDH, err := ecdh.GenerateKey(ecdh.P256(), rand.Reader) if err != nil { t.Error(err) } else { + // KAS-ECC-SSC P-256 ecdh.ECDH(ecdh.P256(), kDH, kDH.PublicKey()) } + // ECDSA PCT kDSA, err := ecdsa.GenerateKey(ecdsa.P256(), rand.Reader) if err != nil { t.Error(err) } else { + // ECDSA P-256 SHA2-512 sign and verify ecdsa.SignDeterministic(ecdsa.P256(), sha256.New, kDSA, make([]byte, 32)) } + // Ed25519 sign and verify PCT k25519, err := ed25519.GenerateKey() if err != nil { t.Error(err) } else { + // Ed25519 sign and verify ed25519.Sign(k25519, make([]byte, 32)) } + // RSA sign and verify PCT kRSA, err := rsa.GenerateKey(rand.Reader, 2048) if err != nil { t.Error(err) } else { + // RSASSA-PKCS-v1.5 2048-bit sign and verify rsa.SignPKCS1v15(kRSA, crypto.SHA256.String(), make([]byte, 32)) } t.Log("completed successfully") From fc88e18b4a781a8751799a123cdac8b29a92409d Mon Sep 17 00:00:00 2001 From: Filippo Valsorda Date: Thu, 11 Sep 2025 21:04:05 +0200 Subject: [PATCH 013/229] crypto/internal/fips140/entropy: add CPU jitter-based entropy source Heavily inspired by the BoringSSL implementation. Change-Id: I6a6a6964b22826d54700c8b3d555054163cef5fe Co-authored-by: Daniel Morsing Cq-Include-Trybots: luci.golang.try:gotip-linux-s390x,gotip-linux-ppc64_power10,gotip-linux-ppc64le_power10,gotip-linux-ppc64le_power8,gotip-linux-arm,gotip-darwin-arm64_15,gotip-windows-arm64,gotip-freebsd-amd64 Reviewed-on: https://go-review.googlesource.com/c/go/+/703015 LUCI-TryBot-Result: Go LUCI Reviewed-by: Roland Shoemaker Reviewed-by: Daniel McCarney Auto-Submit: Filippo Valsorda Reviewed-by: Cherry Mui --- src/crypto/internal/entropy/entropy.go | 6 +- src/crypto/internal/fips140/drbg/rand.go | 61 +++- .../internal/fips140/entropy/entropy.go | 202 ++++++++++++++ src/crypto/internal/fips140/entropy/sha384.go | 191 +++++++++++++ src/crypto/internal/fips140/fips140.go | 2 + .../internal/fips140deps/fipsdeps_test.go | 4 +- src/crypto/internal/fips140deps/time/time.go | 21 ++ .../internal/fips140deps/time/time_windows.go | 17 ++ .../internal/fips140test/entropy_test.go | 264 ++++++++++++++++++ src/go/build/deps_test.go | 5 + 10 files changed, 758 insertions(+), 15 deletions(-) create mode 100644 src/crypto/internal/fips140/entropy/entropy.go create mode 100644 src/crypto/internal/fips140/entropy/sha384.go create mode 100644 src/crypto/internal/fips140deps/time/time.go create mode 100644 src/crypto/internal/fips140deps/time/time_windows.go create mode 100644 src/crypto/internal/fips140test/entropy_test.go diff --git a/src/crypto/internal/entropy/entropy.go b/src/crypto/internal/entropy/entropy.go index 5319e9e47a7455..73fd5298007a11 100644 --- a/src/crypto/internal/entropy/entropy.go +++ b/src/crypto/internal/entropy/entropy.go @@ -3,9 +3,11 @@ // license that can be found in the LICENSE file. // Package entropy provides the passive entropy source for the FIPS 140-3 -// module. It is only used in FIPS mode by [crypto/internal/fips140/drbg.Read]. +// module. It is only used in FIPS mode by [crypto/internal/fips140/drbg.Read] +// from the FIPS 140-3 Go Cryptographic Module v1.0.0. Later versions of the +// module have an internal CPU jitter-based entropy source. // -// This complies with IG 9.3.A, Additional Comment 12, which until January 1, +// This complied with IG 9.3.A, Additional Comment 12, which until January 1, // 2026 allows new modules to meet an [earlier version] of Resolution 2(b): // "A software module that contains an approved DRBG that receives a LOAD // command (or its logical equivalent) with entropy obtained from [...] inside diff --git a/src/crypto/internal/fips140/drbg/rand.go b/src/crypto/internal/fips140/drbg/rand.go index c1a3ea0ae658ff..3ccb018e326047 100644 --- a/src/crypto/internal/fips140/drbg/rand.go +++ b/src/crypto/internal/fips140/drbg/rand.go @@ -9,21 +9,53 @@ package drbg import ( - "crypto/internal/entropy" "crypto/internal/fips140" + "crypto/internal/fips140/entropy" "crypto/internal/randutil" "crypto/internal/sysrand" "io" "sync" + "sync/atomic" ) -var drbgs = sync.Pool{ +// memory is a scratch buffer that is accessed between samples by the entropy +// source to expose it to memory access timings. +// +// We reuse it and share it between Seed calls to avoid the significant (~500µs) +// cost of zeroing a new allocation every time. The entropy source accesses it +// using atomics (and doesn't care about its contents). +// +// It should end up in the .noptrbss section, and become backed by physical pages +// at first use. This ensures that programs that do not use the FIPS 140-3 module +// do not incur any memory use or initialization penalties. +var memory entropy.ScratchBuffer + +func getEntropy() *[SeedSize]byte { + var retries int + seed, err := entropy.Seed(&memory) + for err != nil { + // The CPU jitter-based SP 800-90B entropy source has a non-negligible + // chance of failing the startup health tests. + // + // Each time it does, it enters a permanent failure state, and we + // restart it anew. This is not expected to happen more than a few times + // in a row. + if retries++; retries > 100 { + panic("fips140/drbg: failed to obtain initial entropy") + } + seed, err = entropy.Seed(&memory) + } + return &seed +} + +// getEntropy is very slow (~500µs), so we don't want it on the hot path. +// We keep both a persistent DRBG instance and a pool of additional instances. +// Occasional uses will use drbgInstance, even if the pool was emptied since the +// last use. Frequent concurrent uses will fill the pool and use it. +var drbgInstance atomic.Pointer[Counter] +var drbgPool = sync.Pool{ New: func() any { - var c *Counter - entropy.Depleted(func(seed *[48]byte) { - c = NewCounter(seed) - }) - return c + return NewCounter(getEntropy()) }, } @@ -44,8 +76,15 @@ func Read(b []byte) { additionalInput := new([SeedSize]byte) sysrand.Read(additionalInput[:16]) - drbg := drbgs.Get().(*Counter) - defer drbgs.Put(drbg) + drbg := drbgInstance.Swap(nil) + if drbg == nil { + drbg = drbgPool.Get().(*Counter) + } + defer func() { + if !drbgInstance.CompareAndSwap(nil, drbg) { + drbgPool.Put(drbg) + } + }() for len(b) > 0 { size := min(len(b), maxRequestSize) @@ -54,9 +93,7 @@ func Read(b []byte) { // Section 9.3.2: if Generate reports a reseed is required, the // additional input is passed to Reseed along with the entropy and // then nulled before the next Generate call. - entropy.Depleted(func(seed *[48]byte) { - drbg.Reseed(seed, additionalInput) - }) + drbg.Reseed(getEntropy(), additionalInput) additionalInput = nil continue } diff --git a/src/crypto/internal/fips140/entropy/entropy.go b/src/crypto/internal/fips140/entropy/entropy.go new file mode 100644 index 00000000000000..273f05c817aff8 --- /dev/null +++ b/src/crypto/internal/fips140/entropy/entropy.go @@ -0,0 +1,202 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package entropy implements a CPU jitter-based SP 800-90B entropy source. +package entropy + +import ( + "crypto/internal/fips140deps/time" + "errors" + "sync/atomic" + "unsafe" +) + +// Version returns the version of the entropy source. +// +// This is independent of the FIPS 140-3 module version, in order to reuse the +// ESV certificate across module versions. +func Version() string { + return "v1.0.0" +} + +// ScratchBuffer is a large buffer that will be written to using atomics, to +// generate noise from memory access timings. Its contents do not matter. +type ScratchBuffer [1 << 25]byte + +// Seed returns a 384-bit seed with full entropy. +// +// memory is passed in to allow changing the allocation strategy without +// modifying the frozen and certified entropy source in this package. +// +// Seed returns an error if the entropy source startup health tests fail, which +// has a non-negligible chance of happening. +func Seed(memory *ScratchBuffer) ([48]byte, error) { + // Collect w = 1024 samples, each certified to provide no less than h = 0.5 + // bits of entropy, for a total of hᵢₙ = w × h = 512 bits of entropy, over + // nᵢₙ = w × n = 8192 bits of input data. + var samples [1024]byte + if err := Samples(samples[:], memory); err != nil { + return [48]byte{}, err + } + + // Use a vetted unkeyed conditioning component, SHA-384, with nw = 384 and + // nₒᵤₜ = 384. Per the formula in SP 800-90B Section 3.1.5.1.2, the output + // entropy hₒᵤₜ is: + // + // sage: n_in = 8192 + // sage: n_out = 384 + // sage: nw = 384 + // sage: h_in = 512 + // sage: P_high = 2^(-h_in) + // sage: P_low = (1 - P_high) / (2^n_in - 1) + // sage: n = min(n_out, nw) + // sage: ψ = 2^(n_in - n) * P_low + P_high + // sage: U = 2^(n_in - n) + sqrt(2 * n * 2^(n_in - n) * ln(2)) + // sage: ω = U * P_low + // sage: h_out = -log(max(ψ, ω), 2) + // sage: h_out.n() + // 384.000000000000 + // + // According to Implementation Guidance D.K, Resolution 19, since + // + // - the conditioning component is vetted, + // - hᵢₙ = 512 ≥ nₒᵤₜ + 64 = 448, and + // - nₒᵤₜ ≤ security strength of SHA-384 = 384 (per SP 800-107 Rev. 1, Table 1), + // + // we can claim the output has full entropy. + return SHA384(&samples), nil +} + +// Samples starts a new entropy source, collects the requested number of +// samples, conducts startup health tests, and returns the samples or an error +// if the health tests fail. +// +// The health tests have a non-negligible chance of failing. +func Samples(samples []uint8, memory *ScratchBuffer) error { + if len(samples) < 1024 { + return errors.New("entropy: at least 1024 samples are required for startup health tests") + } + s := newSource(memory) + for range 4 { + // Warm up the source to avoid any initial bias. + _ = s.Sample() + } + for i := range samples { + samples[i] = s.Sample() + } + if err := RepetitionCountTest(samples); err != nil { + return err + } + if err := AdaptiveProportionTest(samples); err != nil { + return err + } + return nil +} + +type source struct { + memory *ScratchBuffer + lcgState uint32 + previous int64 +} + +func newSource(memory *ScratchBuffer) *source { + return &source{ + memory: memory, + lcgState: uint32(time.HighPrecisionNow()), + previous: time.HighPrecisionNow(), + } +} + +// touchMemory performs a write to memory at the given index. +// +// The memory slice is passed in and may be shared across sources e.g. to avoid +// the significant (~500µs) cost of zeroing a new allocation on every [Seed] call. +func touchMemory(memory *ScratchBuffer, idx uint32) { + idx = idx / 4 * 4 // align to 32 bits + u32 := (*uint32)(unsafe.Pointer(&memory[idx])) + last := atomic.LoadUint32(u32) + atomic.SwapUint32(u32, last+13) +} + +func (s *source) Sample() uint8 { + // Perform a few memory accesses in an unpredictable pattern to expose the + // next measurement to as much system noise as possible. + memory, lcgState := s.memory, s.lcgState + _ = memory[0] // hoist the nil check out of touchMemory + for range 64 { + lcgState = 1664525*lcgState + 1013904223 + // Discard the lower bits, which tend to fall into short cycles. + idx := (lcgState >> 6) & (1<<25 - 1) + touchMemory(memory, idx) + } + s.lcgState = lcgState + + t := time.HighPrecisionNow() + sample := t - s.previous + s.previous = t + + // Reduce the symbol space to 256 values, assuming most of the entropy is in + // the least-significant bits, which represent the highest-resolution timing + // differences. + return uint8(sample) +} + +// RepetitionCountTest implements the repetition count test from SP 800-90B +// Section 4.4.1. It returns an error if any symbol is repeated C = 41 or more +// times in a row. +// +// This C value is calculated from a target failure probability α = 2⁻²⁰ and a +// claimed min-entropy per symbol h = 0.5 bits, using the formula in SP 800-90B +// Section 4.4.1. +// +// sage: α = 2^-20 +// sage: H = 0.5 +// sage: 1 + ceil(-log(α, 2) / H) +// 41 +func RepetitionCountTest(samples []uint8) error { + x := samples[0] + count := 1 + for _, y := range samples[1:] { + if y == x { + count++ + if count >= 41 { + return errors.New("entropy: repetition count health test failed") + } + } else { + x = y + count = 1 + } + } + return nil +} + +// AdaptiveProportionTest implements the adaptive proportion test from SP 800-90B +// Section 4.4.2. It returns an error if any symbol appears C = 410 or more +// times in the last W = 512 samples. +// +// This C value is calculated from a target failure probability α = 2⁻²⁰, a +// window size W = 512, and a claimed min-entropy per symbol h = 0.5 bits, using +// the formula in SP 800-90B Section 4.4.2, equivalent to the Microsoft Excel +// formula 1+CRITBINOM(W, power(2,(−H)),1−α). +// +// sage: from scipy.stats import binom +// sage: α = 2^-20 +// sage: H = 0.5 +// sage: W = 512 +// sage: C = 1 + binom.ppf(1 - α, W, 2**(-H)) +// sage: ceil(C) +// 410 +func AdaptiveProportionTest(samples []uint8) error { + var counts [256]int + for i, x := range samples { + counts[x]++ + if i >= 512 { + counts[samples[i-512]]-- + } + if counts[x] >= 410 { + return errors.New("entropy: adaptive proportion health test failed") + } + } + return nil +} diff --git a/src/crypto/internal/fips140/entropy/sha384.go b/src/crypto/internal/fips140/entropy/sha384.go new file mode 100644 index 00000000000000..ec23cfc9ad3661 --- /dev/null +++ b/src/crypto/internal/fips140/entropy/sha384.go @@ -0,0 +1,191 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package entropy + +import "math/bits" + +// This file includes a SHA-384 implementation to insulate the entropy source +// from any changes in the FIPS 140-3 module's crypto/internal/fips140/sha512 +// package. We only support 1024-byte inputs. + +func SHA384(p *[1024]byte) [48]byte { + h := [8]uint64{ + 0xcbbb9d5dc1059ed8, + 0x629a292a367cd507, + 0x9159015a3070dd17, + 0x152fecd8f70e5939, + 0x67332667ffc00b31, + 0x8eb44a8768581511, + 0xdb0c2e0d64f98fa7, + 0x47b5481dbefa4fa4, + } + + sha384Block(&h, (*[128]byte)(p[0:128])) + sha384Block(&h, (*[128]byte)(p[128:256])) + sha384Block(&h, (*[128]byte)(p[256:384])) + sha384Block(&h, (*[128]byte)(p[384:512])) + sha384Block(&h, (*[128]byte)(p[512:640])) + sha384Block(&h, (*[128]byte)(p[640:768])) + sha384Block(&h, (*[128]byte)(p[768:896])) + sha384Block(&h, (*[128]byte)(p[896:1024])) + + var padlen [128]byte + padlen[0] = 0x80 + bePutUint64(padlen[112+8:], 1024*8) + sha384Block(&h, &padlen) + + var digest [48]byte + bePutUint64(digest[0:], h[0]) + bePutUint64(digest[8:], h[1]) + bePutUint64(digest[16:], h[2]) + bePutUint64(digest[24:], h[3]) + bePutUint64(digest[32:], h[4]) + bePutUint64(digest[40:], h[5]) + return digest +} + +var _K = [...]uint64{ + 0x428a2f98d728ae22, + 0x7137449123ef65cd, + 0xb5c0fbcfec4d3b2f, + 0xe9b5dba58189dbbc, + 0x3956c25bf348b538, + 0x59f111f1b605d019, + 0x923f82a4af194f9b, + 0xab1c5ed5da6d8118, + 0xd807aa98a3030242, + 0x12835b0145706fbe, + 0x243185be4ee4b28c, + 0x550c7dc3d5ffb4e2, + 0x72be5d74f27b896f, + 0x80deb1fe3b1696b1, + 0x9bdc06a725c71235, + 0xc19bf174cf692694, + 0xe49b69c19ef14ad2, + 0xefbe4786384f25e3, + 0x0fc19dc68b8cd5b5, + 0x240ca1cc77ac9c65, + 0x2de92c6f592b0275, + 0x4a7484aa6ea6e483, + 0x5cb0a9dcbd41fbd4, + 0x76f988da831153b5, + 0x983e5152ee66dfab, + 0xa831c66d2db43210, + 0xb00327c898fb213f, + 0xbf597fc7beef0ee4, + 0xc6e00bf33da88fc2, + 0xd5a79147930aa725, + 0x06ca6351e003826f, + 0x142929670a0e6e70, + 0x27b70a8546d22ffc, + 0x2e1b21385c26c926, + 0x4d2c6dfc5ac42aed, + 0x53380d139d95b3df, + 0x650a73548baf63de, + 0x766a0abb3c77b2a8, + 0x81c2c92e47edaee6, + 0x92722c851482353b, + 0xa2bfe8a14cf10364, + 0xa81a664bbc423001, + 0xc24b8b70d0f89791, + 0xc76c51a30654be30, + 0xd192e819d6ef5218, + 0xd69906245565a910, + 0xf40e35855771202a, + 0x106aa07032bbd1b8, + 0x19a4c116b8d2d0c8, + 0x1e376c085141ab53, + 0x2748774cdf8eeb99, + 0x34b0bcb5e19b48a8, + 0x391c0cb3c5c95a63, + 0x4ed8aa4ae3418acb, + 0x5b9cca4f7763e373, + 0x682e6ff3d6b2b8a3, + 0x748f82ee5defb2fc, + 0x78a5636f43172f60, + 0x84c87814a1f0ab72, + 0x8cc702081a6439ec, + 0x90befffa23631e28, + 0xa4506cebde82bde9, + 0xbef9a3f7b2c67915, + 0xc67178f2e372532b, + 0xca273eceea26619c, + 0xd186b8c721c0c207, + 0xeada7dd6cde0eb1e, + 0xf57d4f7fee6ed178, + 0x06f067aa72176fba, + 0x0a637dc5a2c898a6, + 0x113f9804bef90dae, + 0x1b710b35131c471b, + 0x28db77f523047d84, + 0x32caab7b40c72493, + 0x3c9ebe0a15c9bebc, + 0x431d67c49c100d4c, + 0x4cc5d4becb3e42b6, + 0x597f299cfc657e2a, + 0x5fcb6fab3ad6faec, + 0x6c44198c4a475817, +} + +func sha384Block(dh *[8]uint64, p *[128]byte) { + var w [80]uint64 + for i := range 80 { + if i < 16 { + w[i] = beUint64(p[i*8:]) + } else { + v1 := w[i-2] + t1 := bits.RotateLeft64(v1, -19) ^ bits.RotateLeft64(v1, -61) ^ (v1 >> 6) + v2 := w[i-15] + t2 := bits.RotateLeft64(v2, -1) ^ bits.RotateLeft64(v2, -8) ^ (v2 >> 7) + + w[i] = t1 + w[i-7] + t2 + w[i-16] + } + } + + a, b, c, d, e, f, g, h := dh[0], dh[1], dh[2], dh[3], dh[4], dh[5], dh[6], dh[7] + + for i := range 80 { + t1 := h + (bits.RotateLeft64(e, -14) ^ bits.RotateLeft64(e, -18) ^ + bits.RotateLeft64(e, -41)) + ((e & f) ^ (^e & g)) + _K[i] + w[i] + t2 := (bits.RotateLeft64(a, -28) ^ bits.RotateLeft64(a, -34) ^ + bits.RotateLeft64(a, -39)) + ((a & b) ^ (a & c) ^ (b & c)) + + h = g + g = f + f = e + e = d + t1 + d = c + c = b + b = a + a = t1 + t2 + } + + dh[0] += a + dh[1] += b + dh[2] += c + dh[3] += d + dh[4] += e + dh[5] += f + dh[6] += g + dh[7] += h +} + +func beUint64(b []byte) uint64 { + _ = b[7] // bounds check hint to compiler; see golang.org/issue/14808 + return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 | + uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56 +} + +func bePutUint64(b []byte, v uint64) { + _ = b[7] // early bounds check to guarantee safety of writes below + b[0] = byte(v >> 56) + b[1] = byte(v >> 48) + b[2] = byte(v >> 40) + b[3] = byte(v >> 32) + b[4] = byte(v >> 24) + b[5] = byte(v >> 16) + b[6] = byte(v >> 8) + b[7] = byte(v) +} diff --git a/src/crypto/internal/fips140/fips140.go b/src/crypto/internal/fips140/fips140.go index d03219b540e27f..76054b00684e2b 100644 --- a/src/crypto/internal/fips140/fips140.go +++ b/src/crypto/internal/fips140/fips140.go @@ -48,6 +48,8 @@ func Supported() error { } // See EnableFIPS in cmd/internal/obj/fips.go for commentary. + // Also, js/wasm and windows/386 don't have good enough timers + // for the CPU jitter entropy source. switch { case runtime.GOARCH == "wasm", runtime.GOOS == "windows" && runtime.GOARCH == "386", diff --git a/src/crypto/internal/fips140deps/fipsdeps_test.go b/src/crypto/internal/fips140deps/fipsdeps_test.go index 2c3bc8184e71bc..97552dc1ce10f1 100644 --- a/src/crypto/internal/fips140deps/fipsdeps_test.go +++ b/src/crypto/internal/fips140deps/fipsdeps_test.go @@ -88,7 +88,8 @@ func TestImports(t *testing.T) { } } - // Ensure that all packages except check and check's dependencies import check. + // Ensure that all packages except check, check's dependencies, and the + // entropy source (which is used only from .../fips140/drbg) import check. for pkg := range allPackages { switch pkg { case "crypto/internal/fips140/check": @@ -99,6 +100,7 @@ func TestImports(t *testing.T) { case "crypto/internal/fips140/sha3": case "crypto/internal/fips140/sha256": case "crypto/internal/fips140/sha512": + case "crypto/internal/fips140/entropy": default: if !importCheck[pkg] { t.Errorf("package %s does not import crypto/internal/fips140/check", pkg) diff --git a/src/crypto/internal/fips140deps/time/time.go b/src/crypto/internal/fips140deps/time/time.go new file mode 100644 index 00000000000000..eea37b772e4351 --- /dev/null +++ b/src/crypto/internal/fips140deps/time/time.go @@ -0,0 +1,21 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +//go:build !windows + +package time + +import "time" + +var start = time.Now() + +// HighPrecisionNow returns a high-resolution timestamp suitable for measuring +// small time differences. It uses the time package's monotonic clock. +// +// Its unit, epoch, and resolution are unspecified, and may change, but can be +// assumed to be sufficiently precise to measure time differences on the order +// of tens to hundreds of nanoseconds. +func HighPrecisionNow() int64 { + return int64(time.Since(start)) +} diff --git a/src/crypto/internal/fips140deps/time/time_windows.go b/src/crypto/internal/fips140deps/time/time_windows.go new file mode 100644 index 00000000000000..410ede4ee91705 --- /dev/null +++ b/src/crypto/internal/fips140deps/time/time_windows.go @@ -0,0 +1,17 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package time + +import "internal/syscall/windows" + +// HighPrecisionNow returns a high-resolution timestamp suitable for measuring +// small time differences. It uses Windows' QueryPerformanceCounter. +// +// Its unit, epoch, and resolution are unspecified, and may change, but can be +// assumed to be sufficiently precise to measure time differences on the order +// of tens to hundreds of nanoseconds. +func HighPrecisionNow() int64 { + return windows.QueryPerformanceCounter() +} diff --git a/src/crypto/internal/fips140test/entropy_test.go b/src/crypto/internal/fips140test/entropy_test.go new file mode 100644 index 00000000000000..76c24289520e17 --- /dev/null +++ b/src/crypto/internal/fips140test/entropy_test.go @@ -0,0 +1,264 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +//go:build !fips140v1.0 + +package fipstest + +import ( + "bytes" + "crypto/internal/cryptotest" + "crypto/internal/fips140/drbg" + "crypto/internal/fips140/entropy" + "crypto/sha256" + "crypto/sha512" + "encoding/hex" + "flag" + "fmt" + "internal/testenv" + "io/fs" + "os" + "path/filepath" + "runtime" + "strings" + "testing" + "time" +) + +var flagEntropySamples = flag.String("entropy-samples", "", "store entropy samples with the provided `suffix`") +var flagNISTSP80090B = flag.Bool("nist-sp800-90b", false, "run NIST SP 800-90B tests (requires docker)") + +func TestEntropySamples(t *testing.T) { + cryptotest.MustSupportFIPS140(t) + + var seqSamples [1_000_000]uint8 + samplesOrTryAgain(t, seqSamples[:]) + seqSamplesName := fmt.Sprintf("entropy_samples_sequential_%s_%s_%s_%s_%s.bin", entropy.Version(), + runtime.GOOS, runtime.GOARCH, *flagEntropySamples, time.Now().Format("20060102T150405Z")) + if *flagEntropySamples != "" { + if err := os.WriteFile(seqSamplesName, seqSamples[:], 0644); err != nil { + t.Fatalf("failed to write samples to %q: %v", seqSamplesName, err) + } + t.Logf("wrote %s", seqSamplesName) + } + + var restartSamples [1000][1000]uint8 + for i := range restartSamples { + var samples [1024]uint8 + samplesOrTryAgain(t, samples[:]) + copy(restartSamples[i][:], samples[:]) + } + restartSamplesName := fmt.Sprintf("entropy_samples_restart_%s_%s_%s_%s_%s.bin", entropy.Version(), + runtime.GOOS, runtime.GOARCH, *flagEntropySamples, time.Now().Format("20060102T150405Z")) + if *flagEntropySamples != "" { + f, err := os.Create(restartSamplesName) + if err != nil { + t.Fatalf("failed to create %q: %v", restartSamplesName, err) + } + for i := range restartSamples { + if _, err := f.Write(restartSamples[i][:]); err != nil { + t.Fatalf("failed to write samples to %q: %v", restartSamplesName, err) + } + } + if err := f.Close(); err != nil { + t.Fatalf("failed to close %q: %v", restartSamplesName, err) + } + t.Logf("wrote %s", restartSamplesName) + } + + if *flagNISTSP80090B { + if *flagEntropySamples == "" { + t.Fatalf("-nist-sp800-90b requires -entropy-samples to be set too") + } + + // Check if the nist-sp800-90b docker image is already present, + // and build it otherwise. + if err := testenv.Command(t, + "docker", "image", "inspect", "nist-sp800-90b", + ).Run(); err != nil { + t.Logf("building nist-sp800-90b docker image") + dockerfile := filepath.Join(t.TempDir(), "Dockerfile.SP800-90B_EntropyAssessment") + if err := os.WriteFile(dockerfile, []byte(NISTSP80090BDockerfile), 0644); err != nil { + t.Fatalf("failed to write Dockerfile: %v", err) + } + out, err := testenv.Command(t, + "docker", "build", "-t", "nist-sp800-90b", "-f", dockerfile, "/var/empty", + ).CombinedOutput() + if err != nil { + t.Fatalf("failed to build nist-sp800-90b docker image: %v\n%s", err, out) + } + } + + pwd, err := os.Getwd() + if err != nil { + t.Fatalf("failed to get current working directory: %v", err) + } + t.Logf("running ea_non_iid analysis") + out, err := testenv.Command(t, + "docker", "run", "--rm", "-v", fmt.Sprintf("%s:%s", pwd, pwd), "-w", pwd, + "nist-sp800-90b", "ea_non_iid", seqSamplesName, "8", + ).CombinedOutput() + if err != nil { + t.Fatalf("ea_non_iid failed: %v\n%s", err, out) + } + t.Logf("\n%s", out) + + H_I := string(out) + H_I = strings.TrimSpace(H_I[strings.LastIndexByte(H_I, ' ')+1:]) + t.Logf("running ea_restart analysis with H_I = %s", H_I) + out, err = testenv.Command(t, + "docker", "run", "--rm", "-v", fmt.Sprintf("%s:%s", pwd, pwd), "-w", pwd, + "nist-sp800-90b", "ea_restart", restartSamplesName, "8", H_I, + ).CombinedOutput() + if err != nil { + t.Fatalf("ea_restart failed: %v\n%s", err, out) + } + t.Logf("\n%s", out) + } +} + +var NISTSP80090BDockerfile = ` +FROM ubuntu:24.04 +RUN apt-get update && apt-get install -y build-essential git \ + libbz2-dev libdivsufsort-dev libjsoncpp-dev libgmp-dev libmpfr-dev libssl-dev \ + && rm -rf /var/lib/apt/lists/* +RUN git clone --depth 1 https://github.com/usnistgov/SP800-90B_EntropyAssessment.git +RUN cd SP800-90B_EntropyAssessment && git checkout 8924f158c97e7b805e0f95247403ad4c44b9cd6f +WORKDIR ./SP800-90B_EntropyAssessment/cpp/ +RUN make all +RUN cd selftest && ./selftest +RUN cp ea_non_iid ea_restart /usr/local/bin/ +` + +var memory entropy.ScratchBuffer + +// samplesOrTryAgain calls entropy.Samples up to 10 times until it succeeds. +// Samples has a non-negligible chance of failing the health tests, as required +// by SP 800-90B. +func samplesOrTryAgain(t *testing.T, samples []uint8) { + t.Helper() + for range 10 { + if err := entropy.Samples(samples, &memory); err != nil { + t.Logf("entropy.Samples() failed: %v", err) + continue + } + return + } + t.Fatal("entropy.Samples() failed 10 times in a row") +} + +func TestEntropySHA384(t *testing.T) { + var input [1024]uint8 + for i := range input { + input[i] = uint8(i) + } + want := sha512.Sum384(input[:]) + got := entropy.SHA384(&input) + if got != want { + t.Errorf("SHA384() = %x, want %x", got, want) + } +} + +func TestEntropyRepetitionCountTest(t *testing.T) { + good := bytes.Repeat(append(bytes.Repeat([]uint8{42}, 40), 1), 100) + if err := entropy.RepetitionCountTest(good); err != nil { + t.Errorf("RepetitionCountTest(good) = %v, want nil", err) + } + + bad := bytes.Repeat([]uint8{0}, 40) + bad = append(bad, bytes.Repeat([]uint8{1}, 40)...) + bad = append(bad, bytes.Repeat([]uint8{42}, 41)...) + bad = append(bad, bytes.Repeat([]uint8{2}, 40)...) + if err := entropy.RepetitionCountTest(bad); err == nil { + t.Error("RepetitionCountTest(bad) = nil, want error") + } + + bad = bytes.Repeat([]uint8{42}, 41) + if err := entropy.RepetitionCountTest(bad); err == nil { + t.Error("RepetitionCountTest(bad) = nil, want error") + } +} + +func TestEntropyAdaptiveProportionTest(t *testing.T) { + good := bytes.Repeat([]uint8{0}, 409) + good = append(good, bytes.Repeat([]uint8{1}, 512-409)...) + good = append(good, bytes.Repeat([]uint8{0}, 409)...) + if err := entropy.AdaptiveProportionTest(good); err != nil { + t.Errorf("AdaptiveProportionTest(good) = %v, want nil", err) + } + + // These fall out of the window. + bad := bytes.Repeat([]uint8{1}, 100) + bad = append(bad, bytes.Repeat([]uint8{1, 2, 3, 4, 5, 6}, 100)...) + // These are in the window. + bad = append(bad, bytes.Repeat([]uint8{42}, 410)...) + if err := entropy.AdaptiveProportionTest(bad[:len(bad)-1]); err != nil { + t.Errorf("AdaptiveProportionTest(bad[:len(bad)-1]) = %v, want nil", err) + } + if err := entropy.AdaptiveProportionTest(bad); err == nil { + t.Error("AdaptiveProportionTest(bad) = nil, want error") + } +} + +func TestEntropyUnchanged(t *testing.T) { + testenv.MustHaveSource(t) + + h := sha256.New() + root := os.DirFS("../fips140/entropy") + if err := fs.WalkDir(root, ".", func(path string, d fs.DirEntry, err error) error { + if err != nil { + return err + } + if d.IsDir() { + return nil + } + data, err := fs.ReadFile(root, path) + if err != nil { + return err + } + t.Logf("Hashing %s (%d bytes)", path, len(data)) + fmt.Fprintf(h, "%s %d\n", path, len(data)) + h.Write(data) + return nil + }); err != nil { + t.Fatalf("WalkDir: %v", err) + } + + // The crypto/internal/fips140/entropy package is certified as a FIPS 140-3 + // entropy source through the Entropy Source Validation program, + // independently of the FIPS 140-3 module. It must not change even across + // FIPS 140-3 module versions, in order to reuse the ESV certificate. + exp := "35976eb8a11678c79777da07aaab5511d4325701f837777df205f6e7b20c6821" + if got := hex.EncodeToString(h.Sum(nil)); got != exp { + t.Errorf("hash of crypto/internal/fips140/entropy = %s, want %s", got, exp) + } +} + +func TestEntropyRace(t *testing.T) { + // Check that concurrent calls to Seed don't trigger the race detector. + for range 2 { + go func() { + _, _ = entropy.Seed(&memory) + }() + } + // Same, with the higher-level DRBG. More concurrent calls to hit the Pool. + for range 16 { + go func() { + var b [64]byte + drbg.Read(b[:]) + }() + } +} + +var sink byte + +func BenchmarkEntropySeed(b *testing.B) { + for b.Loop() { + seed, err := entropy.Seed(&memory) + if err != nil { + b.Fatalf("entropy.Seed() failed: %v", err) + } + sink ^= seed[0] + } +} diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go index d50a98d34c9092..c76b254b23ffc8 100644 --- a/src/go/build/deps_test.go +++ b/src/go/build/deps_test.go @@ -485,11 +485,16 @@ var depsRules = ` internal/byteorder < crypto/internal/fips140deps/byteorder; internal/cpu, internal/goarch < crypto/internal/fips140deps/cpu; internal/godebug < crypto/internal/fips140deps/godebug; + time, internal/syscall/windows < crypto/internal/fips140deps/time; + + crypto/internal/fips140deps/time, errors, math/bits, sync/atomic, unsafe + < crypto/internal/fips140/entropy; STR, hash, crypto/internal/impl, crypto/internal/entropy, crypto/internal/randutil, + crypto/internal/fips140/entropy, crypto/internal/fips140deps/byteorder, crypto/internal/fips140deps/cpu, crypto/internal/fips140deps/godebug From 75c87df58ebfb24592d7002ef71912f8708dc424 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Tue, 16 Sep 2025 10:52:49 +0200 Subject: [PATCH 014/229] internal/poll: pass the I/O mode instead of an overlapped object in execIO execIO callers should be agnostic to the fact that it uses an overlapped object. This will unlock future optimizations and simplifications. Change-Id: I0a58d992101fa74ac75e3538af04cbc44156f0d6 Reviewed-on: https://go-review.googlesource.com/c/go/+/704175 Reviewed-by: Damien Neil LUCI-TryBot-Result: Go LUCI Reviewed-by: Junyang Shao --- src/internal/poll/fd_windows.go | 64 ++++++++++++++------------- src/internal/poll/sendfile_windows.go | 8 +--- 2 files changed, 35 insertions(+), 37 deletions(-) diff --git a/src/internal/poll/fd_windows.go b/src/internal/poll/fd_windows.go index 9323e49eb745d7..a6ecdafc3404c5 100644 --- a/src/internal/poll/fd_windows.go +++ b/src/internal/poll/fd_windows.go @@ -250,12 +250,16 @@ func (fd *FD) cancelIO(o *operation) { // It supports both synchronous and asynchronous IO. // o.qty and o.flags are set to zero before calling submit // to avoid reusing the values from a previous call. -func (fd *FD) execIO(o *operation, submit func(o *operation) (uint32, error)) (int, error) { +func (fd *FD) execIO(mode int, submit func(o *operation) (uint32, error)) (int, error) { // Notify runtime netpoll about starting IO. - err := fd.pd.prepare(int(o.mode), fd.isFile) + err := fd.pd.prepare(mode, fd.isFile) if err != nil { return 0, err } + o := &fd.rop + if mode == 'w' { + o = &fd.wop + } // Start IO. if !fd.isBlocking && o.o.HEvent == 0 && !fd.pollable() { // If the handle is opened for overlapped IO but we can't @@ -552,7 +556,7 @@ func (fd *FD) Read(buf []byte) (int, error) { case kindConsole: n, err = fd.readConsole(buf) case kindFile, kindPipe: - n, err = fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err = fd.execIO('r', func(o *operation) (qty uint32, err error) { err = syscall.ReadFile(fd.Sysfd, buf, &qty, fd.overlapped(o)) return qty, err }) @@ -567,7 +571,7 @@ func (fd *FD) Read(buf []byte) (int, error) { } } case kindNet: - n, err = fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err = fd.execIO('r', func(o *operation) (qty uint32, err error) { var flags uint32 err = syscall.WSARecv(fd.Sysfd, newWsaBuf(buf), 1, &qty, &flags, &o.o, nil) return qty, err @@ -694,7 +698,7 @@ func (fd *FD) Pread(buf []byte, off int64) (int, error) { defer fd.setOffset(curoffset) } fd.setOffset(off) - n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { err = syscall.ReadFile(fd.Sysfd, buf, &qty, &o.o) return qty, err }) @@ -727,7 +731,7 @@ func (fd *FD) ReadFrom(buf []byte) (int, syscall.Sockaddr, error) { rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) - n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { rsan := int32(unsafe.Sizeof(*rsa)) var flags uint32 err = syscall.WSARecvFrom(fd.Sysfd, newWsaBuf(buf), 1, &qty, &flags, rsa, &rsan, &o.o, nil) @@ -761,7 +765,7 @@ func (fd *FD) ReadFromInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error) rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) - n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { rsan := int32(unsafe.Sizeof(*rsa)) var flags uint32 err = syscall.WSARecvFrom(fd.Sysfd, newWsaBuf(buf), 1, &qty, &flags, rsa, &rsan, &o.o, nil) @@ -795,7 +799,7 @@ func (fd *FD) ReadFromInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error) rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) - n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { rsan := int32(unsafe.Sizeof(*rsa)) var flags uint32 err = syscall.WSARecvFrom(fd.Sysfd, newWsaBuf(buf), 1, &qty, &flags, rsa, &rsan, &o.o, nil) @@ -841,7 +845,7 @@ func (fd *FD) Write(buf []byte) (int, error) { case kindConsole: n, err = fd.writeConsole(b) case kindPipe, kindFile: - n, err = fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err = fd.execIO('w', func(o *operation) (qty uint32, err error) { err = syscall.WriteFile(fd.Sysfd, b, &qty, fd.overlapped(o)) return qty, err }) @@ -850,7 +854,7 @@ func (fd *FD) Write(buf []byte) (int, error) { if race.Enabled { race.ReleaseMerge(unsafe.Pointer(&ioSync)) } - n, err = fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err = fd.execIO('w', func(o *operation) (qty uint32, err error) { err = syscall.WSASend(fd.Sysfd, newWsaBuf(b), 1, &qty, 0, &o.o, nil) return qty, err }) @@ -949,7 +953,7 @@ func (fd *FD) Pwrite(buf []byte, off int64) (int, error) { max = ntotal + maxRW } fd.setOffset(off + int64(ntotal)) - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = syscall.WriteFile(fd.Sysfd, buf[ntotal:max], &qty, &o.o) return qty, err }) @@ -979,7 +983,7 @@ func (fd *FD) Writev(buf *[][]byte) (int64, error) { } bufs := newWSABufs(buf) defer freeWSABufs(bufs) - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = syscall.WSASend(fd.Sysfd, &(*bufs)[0], uint32(len(*bufs)), &qty, 0, &o.o, nil) return qty, err }) @@ -997,7 +1001,7 @@ func (fd *FD) WriteTo(buf []byte, sa syscall.Sockaddr) (int, error) { if len(buf) == 0 { // handle zero-byte payload - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = syscall.WSASendto(fd.Sysfd, &syscall.WSABuf{}, 1, &qty, 0, sa, &o.o, nil) return qty, err }) @@ -1015,7 +1019,7 @@ func (fd *FD) WriteTo(buf []byte, sa syscall.Sockaddr) (int, error) { if len(b) > maxRW { b = b[:maxRW] } - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = syscall.WSASendto(fd.Sysfd, newWsaBuf(b), 1, &qty, 0, sa, &o.o, nil) return qty, err }) @@ -1037,7 +1041,7 @@ func (fd *FD) WriteToInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error) if len(buf) == 0 { // handle zero-byte payload - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = windows.WSASendtoInet4(fd.Sysfd, &syscall.WSABuf{}, 1, &qty, 0, sa4, &o.o, nil) return qty, err }) @@ -1055,7 +1059,7 @@ func (fd *FD) WriteToInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error) if len(b) > maxRW { b = b[:maxRW] } - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = windows.WSASendtoInet4(fd.Sysfd, newWsaBuf(b), 1, &qty, 0, sa4, &o.o, nil) return qty, err }) @@ -1077,7 +1081,7 @@ func (fd *FD) WriteToInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error) if len(buf) == 0 { // handle zero-byte payload - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = windows.WSASendtoInet6(fd.Sysfd, &syscall.WSABuf{}, 1, &qty, 0, sa6, &o.o, nil) return qty, err }) @@ -1095,7 +1099,7 @@ func (fd *FD) WriteToInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error) if len(b) > maxRW { b = b[:maxRW] } - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = windows.WSASendtoInet6(fd.Sysfd, newWsaBuf(b), 1, &qty, 0, sa6, &o.o, nil) return qty, err }) @@ -1112,17 +1116,16 @@ func (fd *FD) WriteToInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error) // called when the descriptor is first created. This is here rather // than in the net package so that it can use fd.wop. func (fd *FD) ConnectEx(ra syscall.Sockaddr) error { - o := &fd.wop - _, err := fd.execIO(o, func(o *operation) (uint32, error) { + _, err := fd.execIO('w', func(o *operation) (uint32, error) { return 0, ConnectExFunc(fd.Sysfd, ra, nil, 0, nil, &o.o) }) return err } -func (fd *FD) acceptOne(s syscall.Handle, rawsa []syscall.RawSockaddrAny, o *operation) (string, error) { +func (fd *FD) acceptOne(s syscall.Handle, rawsa []syscall.RawSockaddrAny) (string, error) { // Submit accept request. rsan := uint32(unsafe.Sizeof(rawsa[0])) - _, err := fd.execIO(o, func(o *operation) (qty uint32, err error) { + _, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { err = AcceptFunc(fd.Sysfd, s, (*byte)(unsafe.Pointer(&rawsa[0])), 0, rsan, rsan, &qty, &o.o) return qty, err @@ -1150,7 +1153,6 @@ func (fd *FD) Accept(sysSocket func() (syscall.Handle, error)) (syscall.Handle, } defer fd.readUnlock() - o := &fd.rop var rawsa [2]syscall.RawSockaddrAny for { s, err := sysSocket() @@ -1158,7 +1160,7 @@ func (fd *FD) Accept(sysSocket func() (syscall.Handle, error)) (syscall.Handle, return syscall.InvalidHandle, nil, 0, "", err } - errcall, err := fd.acceptOne(s, rawsa[:], o) + errcall, err := fd.acceptOne(s, rawsa[:]) if err == nil { return s, rawsa[:], uint32(unsafe.Sizeof(rawsa[0])), "", nil } @@ -1286,7 +1288,7 @@ func (fd *FD) RawRead(f func(uintptr) bool) error { // Use a zero-byte read as a way to get notified when this // socket is readable. h/t https://stackoverflow.com/a/42019668/332798 - _, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + _, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { var flags uint32 if !fd.IsStream { flags |= windows.MSG_PEEK @@ -1381,7 +1383,7 @@ func (fd *FD) ReadMsg(p []byte, oob []byte, flags int) (int, int, int, syscall.S msg := newWSAMsg(p, oob, flags, true) defer freeWSAMsg(msg) - n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { err = windows.WSARecvMsg(fd.Sysfd, msg, &qty, &o.o, nil) return qty, err }) @@ -1406,7 +1408,7 @@ func (fd *FD) ReadMsgInet4(p []byte, oob []byte, flags int, sa4 *syscall.Sockadd msg := newWSAMsg(p, oob, flags, true) defer freeWSAMsg(msg) - n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { err = windows.WSARecvMsg(fd.Sysfd, msg, &qty, &o.o, nil) return qty, err }) @@ -1430,7 +1432,7 @@ func (fd *FD) ReadMsgInet6(p []byte, oob []byte, flags int, sa6 *syscall.Sockadd msg := newWSAMsg(p, oob, flags, true) defer freeWSAMsg(msg) - n, err := fd.execIO(&fd.rop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('r', func(o *operation) (qty uint32, err error) { err = windows.WSARecvMsg(fd.Sysfd, msg, &qty, &o.o, nil) return qty, err }) @@ -1461,7 +1463,7 @@ func (fd *FD) WriteMsg(p []byte, oob []byte, sa syscall.Sockaddr) (int, int, err return 0, 0, err } } - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = windows.WSASendMsg(fd.Sysfd, msg, 0, nil, &o.o, nil) return qty, err }) @@ -1484,7 +1486,7 @@ func (fd *FD) WriteMsgInet4(p []byte, oob []byte, sa *syscall.SockaddrInet4) (in if sa != nil { msg.Namelen = sockaddrInet4ToRaw(msg.Name, sa) } - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = windows.WSASendMsg(fd.Sysfd, msg, 0, nil, &o.o, nil) return qty, err }) @@ -1507,7 +1509,7 @@ func (fd *FD) WriteMsgInet6(p []byte, oob []byte, sa *syscall.SockaddrInet6) (in if sa != nil { msg.Namelen = sockaddrInet6ToRaw(msg.Name, sa) } - n, err := fd.execIO(&fd.wop, func(o *operation) (qty uint32, err error) { + n, err := fd.execIO('w', func(o *operation) (qty uint32, err error) { err = windows.WSASendMsg(fd.Sysfd, msg, 0, nil, &o.o, nil) return qty, err }) diff --git a/src/internal/poll/sendfile_windows.go b/src/internal/poll/sendfile_windows.go index a052f4a1f82400..2bdfecf0134b62 100644 --- a/src/internal/poll/sendfile_windows.go +++ b/src/internal/poll/sendfile_windows.go @@ -62,18 +62,14 @@ func SendFile(fd *FD, src uintptr, size int64) (written int64, err error, handle // See https://docs.microsoft.com/en-us/windows/win32/api/mswsock/nf-mswsock-transmitfile const maxChunkSizePerCall = int64(0x7fffffff - 1) - o := &fd.wop for size > 0 { chunkSize := maxChunkSizePerCall if chunkSize > size { chunkSize = size } - off := startpos + written - o.o.Offset = uint32(off) - o.o.OffsetHigh = uint32(off >> 32) - - n, err := fd.execIO(o, func(o *operation) (uint32, error) { + fd.setOffset(startpos + written) + n, err := fd.execIO('w', func(o *operation) (uint32, error) { err := syscall.TransmitFile(fd.Sysfd, hsrc, uint32(chunkSize), 0, &o.o, nil, syscall.TF_WRITE_BEHIND) if err != nil { return 0, err From db10db6be361f4eaf5f81890e487a9cbf3ca5a53 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Tue, 16 Sep 2025 14:12:25 +0200 Subject: [PATCH 015/229] internal/poll: remove operation fields from FD Use a sync.Pool to reuse the overlapped object passed to the different Windows syscalls instead of keeping two of them in the FD struct. This reduces the size of the FD struct from 248 to 152 bytes. While here, pin the overlapped object for the duration of the overlapped IO operation to comply with the memory safety rules. Cq-Include-Trybots: luci.golang.try:gotip-windows-amd64-longtest,gotip-windows-amd64-race Change-Id: I0161d163f681fe94b822c0c885aaa42c449e5342 Reviewed-on: https://go-review.googlesource.com/c/go/+/704235 Reviewed-by: Damien Neil LUCI-TryBot-Result: Go LUCI Reviewed-by: Junyang Shao --- src/internal/poll/fd_windows.go | 132 ++++++++++++++------------------ 1 file changed, 59 insertions(+), 73 deletions(-) diff --git a/src/internal/poll/fd_windows.go b/src/internal/poll/fd_windows.go index a6ecdafc3404c5..6443f6eb30b8a5 100644 --- a/src/internal/poll/fd_windows.go +++ b/src/internal/poll/fd_windows.go @@ -78,22 +78,6 @@ type operation struct { mode int32 } -func (o *operation) setEvent() { - h, err := windows.CreateEvent(nil, 0, 0, nil) - if err != nil { - // This shouldn't happen when all CreateEvent arguments are zero. - panic(err) - } - // Set the low bit so that the external IOCP doesn't receive the completion packet. - o.o.HEvent = h | 1 -} - -func (o *operation) close() { - if o.o.HEvent != 0 { - syscall.CloseHandle(o.o.HEvent) - } -} - func (fd *FD) overlapped(o *operation) *syscall.Overlapped { if fd.isBlocking { // Don't return the overlapped object if the file handle @@ -208,6 +192,12 @@ var wsaRsaPool = sync.Pool{ }, } +var operationPool = sync.Pool{ + New: func() any { + return new(operation) + }, +} + // waitIO waits for the IO operation o to complete. func (fd *FD) waitIO(o *operation) error { if fd.isBlocking { @@ -246,27 +236,57 @@ func (fd *FD) cancelIO(o *operation) { fd.pd.waitCanceled(int(o.mode)) } +// pin pins ptr for the duration of the IO operation. +// If fd is in blocking mode, pin does nothing. +func (fd *FD) pin(mode int, ptr any) { + if fd.isBlocking { + return + } + if mode == 'r' { + fd.readPinner.Pin(ptr) + } else { + fd.writePinner.Pin(ptr) + } +} + // execIO executes a single IO operation o. // It supports both synchronous and asynchronous IO. -// o.qty and o.flags are set to zero before calling submit -// to avoid reusing the values from a previous call. func (fd *FD) execIO(mode int, submit func(o *operation) (uint32, error)) (int, error) { + if mode == 'r' { + defer fd.readPinner.Unpin() + } else { + defer fd.writePinner.Unpin() + } // Notify runtime netpoll about starting IO. err := fd.pd.prepare(mode, fd.isFile) if err != nil { return 0, err } - o := &fd.rop - if mode == 'w' { - o = &fd.wop + o := operationPool.Get().(*operation) + defer operationPool.Put(o) + *o = operation{ + o: syscall.Overlapped{ + OffsetHigh: uint32(fd.offset >> 32), + Offset: uint32(fd.offset), + }, + runtimeCtx: fd.pd.runtimeCtx, + mode: int32(mode), } // Start IO. - if !fd.isBlocking && o.o.HEvent == 0 && !fd.pollable() { + if !fd.isBlocking && !fd.pollable() { // If the handle is opened for overlapped IO but we can't // use the runtime poller, then we need to use an // event to wait for the IO to complete. - o.setEvent() + h, err := windows.CreateEvent(nil, 0, 0, nil) + if err != nil { + // This shouldn't happen when all CreateEvent arguments are zero. + panic(err) + } + // Set the low bit so that the external IOCP doesn't receive the completion packet. + o.o.HEvent = h | 1 + defer syscall.CloseHandle(h) } + fd.pin(mode, o) qty, err := submit(o) var waitErr error // Blocking operations shouldn't return ERROR_IO_PENDING. @@ -321,11 +341,6 @@ type FD struct { // System file descriptor. Immutable until Close. Sysfd syscall.Handle - // Read operation. - rop operation - // Write operation. - wop operation - // I/O poller. pd pollDesc @@ -364,6 +379,8 @@ type FD struct { disassociated atomic.Bool + // readPinner and writePinner are automatically unpinned + // before execIO returns. readPinner runtime.Pinner writePinner runtime.Pinner } @@ -383,8 +400,6 @@ type FD struct { // using an external mechanism. func (fd *FD) setOffset(off int64) { fd.offset = off - fd.rop.o.OffsetHigh, fd.rop.o.Offset = uint32(off>>32), uint32(off) - fd.wop.o.OffsetHigh, fd.wop.o.Offset = uint32(off>>32), uint32(off) } // addOffset adds the given offset to the current offset. @@ -435,8 +450,6 @@ func (fd *FD) Init(net string, pollable bool) error { } fd.isFile = fd.kind != kindNet fd.isBlocking = !pollable - fd.rop.mode = 'r' - fd.wop.mode = 'w' // It is safe to add overlapped handles that also perform I/O // outside of the runtime poller. The runtime poller will ignore @@ -445,8 +458,6 @@ func (fd *FD) Init(net string, pollable bool) error { if err != nil { return err } - fd.rop.runtimeCtx = fd.pd.runtimeCtx - fd.wop.runtimeCtx = fd.pd.runtimeCtx if fd.kind != kindNet || socketCanUseSetFileCompletionNotificationModes { // Non-socket handles can use SetFileCompletionNotificationModes without problems. err := syscall.SetFileCompletionNotificationModes(fd.Sysfd, @@ -485,8 +496,6 @@ func (fd *FD) destroy() error { if fd.Sysfd == syscall.InvalidHandle { return syscall.EINVAL } - fd.rop.close() - fd.wop.close() // Poller may want to unregister fd in readiness notification mechanism, // so this must be executed before fd.CloseFunc. fd.pd.close() @@ -541,9 +550,8 @@ func (fd *FD) Read(buf []byte) (int, error) { defer fd.readUnlock() } - if len(buf) > 0 && !fd.isBlocking { - fd.readPinner.Pin(&buf[0]) - defer fd.readPinner.Unpin() + if len(buf) > 0 { + fd.pin('r', &buf[0]) } if len(buf) > maxRW { @@ -672,9 +680,8 @@ func (fd *FD) Pread(buf []byte, off int64) (int, error) { } defer fd.readWriteUnlock() - if len(buf) > 0 && !fd.isBlocking { - fd.readPinner.Pin(&buf[0]) - defer fd.readPinner.Unpin() + if len(buf) > 0 { + fd.pin('r', &buf[0]) } if len(buf) > maxRW { @@ -724,10 +731,7 @@ func (fd *FD) ReadFrom(buf []byte) (int, syscall.Sockaddr, error) { } defer fd.readUnlock() - if !fd.isBlocking { - fd.readPinner.Pin(&buf[0]) - defer fd.readPinner.Unpin() - } + fd.pin('r', &buf[0]) rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) @@ -758,10 +762,7 @@ func (fd *FD) ReadFromInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error) } defer fd.readUnlock() - if !fd.isBlocking { - fd.readPinner.Pin(&buf[0]) - defer fd.readPinner.Unpin() - } + fd.pin('r', &buf[0]) rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) @@ -792,10 +793,7 @@ func (fd *FD) ReadFromInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error) } defer fd.readUnlock() - if !fd.isBlocking { - fd.readPinner.Pin(&buf[0]) - defer fd.readPinner.Unpin() - } + fd.pin('r', &buf[0]) rsa := wsaRsaPool.Get().(*syscall.RawSockaddrAny) defer wsaRsaPool.Put(rsa) @@ -827,11 +825,9 @@ func (fd *FD) Write(buf []byte) (int, error) { defer fd.writeUnlock() } - if len(buf) > 0 && !fd.isBlocking { - fd.writePinner.Pin(&buf[0]) - defer fd.writePinner.Unpin() + if len(buf) > 0 { + fd.pin('w', &buf[0]) } - var ntotal int for { max := len(buf) @@ -924,9 +920,8 @@ func (fd *FD) Pwrite(buf []byte, off int64) (int, error) { } defer fd.readWriteUnlock() - if len(buf) > 0 && !fd.isBlocking { - fd.writePinner.Pin(&buf[0]) - defer fd.writePinner.Unpin() + if len(buf) > 0 { + fd.pin('w', &buf[0]) } if fd.isBlocking { @@ -1008,10 +1003,7 @@ func (fd *FD) WriteTo(buf []byte, sa syscall.Sockaddr) (int, error) { return n, err } - if !fd.isBlocking { - fd.writePinner.Pin(&buf[0]) - defer fd.writePinner.Unpin() - } + fd.pin('w', &buf[0]) ntotal := 0 for len(buf) > 0 { @@ -1048,10 +1040,7 @@ func (fd *FD) WriteToInet4(buf []byte, sa4 *syscall.SockaddrInet4) (int, error) return n, err } - if !fd.isBlocking { - fd.writePinner.Pin(&buf[0]) - defer fd.writePinner.Unpin() - } + fd.pin('w', &buf[0]) ntotal := 0 for len(buf) > 0 { @@ -1088,10 +1077,7 @@ func (fd *FD) WriteToInet6(buf []byte, sa6 *syscall.SockaddrInet6) (int, error) return n, err } - if !fd.isBlocking { - fd.writePinner.Pin(&buf[0]) - defer fd.writePinner.Unpin() - } + fd.pin('w', &buf[0]) ntotal := 0 for len(buf) > 0 { From 742f92063e5acc3671a0bd9982e7678d864008f0 Mon Sep 17 00:00:00 2001 From: Cherry Mui Date: Mon, 29 Sep 2025 16:14:24 -0400 Subject: [PATCH 016/229] cmd/compile, runtime: always enable Wasm signext and satconv features These features have been standardized since at least Wasm 2.0. Always enable them. The corresponding GOWASM settings are now no-op. Change-Id: I0e59f21696a69a4e289127988aad629a720b002b Reviewed-on: https://go-review.googlesource.com/c/go/+/707855 LUCI-TryBot-Result: Go LUCI Reviewed-by: David Chase --- src/cmd/compile/internal/ssa/_gen/Wasm.rules | 9 +- src/cmd/compile/internal/ssa/rewriteWasm.go | 109 ------------------- src/cmd/compile/internal/wasm/ssa.go | 21 +--- src/internal/buildcfg/cfg.go | 25 ++--- src/runtime/conv_wasm_test.go | 45 ++++---- src/runtime/sys_wasm.s | 58 ---------- 6 files changed, 38 insertions(+), 229 deletions(-) diff --git a/src/cmd/compile/internal/ssa/_gen/Wasm.rules b/src/cmd/compile/internal/ssa/_gen/Wasm.rules index f3bd8d8b4f18f1..f632a01109f764 100644 --- a/src/cmd/compile/internal/ssa/_gen/Wasm.rules +++ b/src/cmd/compile/internal/ssa/_gen/Wasm.rules @@ -55,12 +55,9 @@ (ZeroExt32to64 x:(I64Load32U _ _)) => x (ZeroExt16to(64|32) x:(I64Load16U _ _)) => x (ZeroExt8to(64|32|16) x:(I64Load8U _ _)) => x -(SignExt32to64 x) && buildcfg.GOWASM.SignExt => (I64Extend32S x) -(SignExt8to(64|32|16) x) && buildcfg.GOWASM.SignExt => (I64Extend8S x) -(SignExt16to(64|32) x) && buildcfg.GOWASM.SignExt => (I64Extend16S x) -(SignExt32to64 x) => (I64ShrS (I64Shl x (I64Const [32])) (I64Const [32])) -(SignExt16to(64|32) x) => (I64ShrS (I64Shl x (I64Const [48])) (I64Const [48])) -(SignExt8to(64|32|16) x) => (I64ShrS (I64Shl x (I64Const [56])) (I64Const [56])) +(SignExt32to64 x) => (I64Extend32S x) +(SignExt8to(64|32|16) x) => (I64Extend8S x) +(SignExt16to(64|32) x) => (I64Extend16S x) (ZeroExt32to64 x) => (I64And x (I64Const [0xffffffff])) (ZeroExt16to(64|32) x) => (I64And x (I64Const [0xffff])) (ZeroExt8to(64|32|16) x) => (I64And x (I64Const [0xff])) diff --git a/src/cmd/compile/internal/ssa/rewriteWasm.go b/src/cmd/compile/internal/ssa/rewriteWasm.go index c3c5528aaa6ab4..a164a6eee555b9 100644 --- a/src/cmd/compile/internal/ssa/rewriteWasm.go +++ b/src/cmd/compile/internal/ssa/rewriteWasm.go @@ -2,7 +2,6 @@ package ssa -import "internal/buildcfg" import "math" import "cmd/compile/internal/types" @@ -3202,8 +3201,6 @@ func rewriteValueWasm_OpRsh8x8(v *Value) bool { } func rewriteValueWasm_OpSignExt16to32(v *Value) bool { v_0 := v.Args[0] - b := v.Block - typ := &b.Func.Config.Types // match: (SignExt16to32 x:(I64Load16S _ _)) // result: x for { @@ -3215,34 +3212,16 @@ func rewriteValueWasm_OpSignExt16to32(v *Value) bool { return true } // match: (SignExt16to32 x) - // cond: buildcfg.GOWASM.SignExt // result: (I64Extend16S x) for { x := v_0 - if !(buildcfg.GOWASM.SignExt) { - break - } v.reset(OpWasmI64Extend16S) v.AddArg(x) return true } - // match: (SignExt16to32 x) - // result: (I64ShrS (I64Shl x (I64Const [48])) (I64Const [48])) - for { - x := v_0 - v.reset(OpWasmI64ShrS) - v0 := b.NewValue0(v.Pos, OpWasmI64Shl, typ.Int64) - v1 := b.NewValue0(v.Pos, OpWasmI64Const, typ.Int64) - v1.AuxInt = int64ToAuxInt(48) - v0.AddArg2(x, v1) - v.AddArg2(v0, v1) - return true - } } func rewriteValueWasm_OpSignExt16to64(v *Value) bool { v_0 := v.Args[0] - b := v.Block - typ := &b.Func.Config.Types // match: (SignExt16to64 x:(I64Load16S _ _)) // result: x for { @@ -3254,34 +3233,16 @@ func rewriteValueWasm_OpSignExt16to64(v *Value) bool { return true } // match: (SignExt16to64 x) - // cond: buildcfg.GOWASM.SignExt // result: (I64Extend16S x) for { x := v_0 - if !(buildcfg.GOWASM.SignExt) { - break - } v.reset(OpWasmI64Extend16S) v.AddArg(x) return true } - // match: (SignExt16to64 x) - // result: (I64ShrS (I64Shl x (I64Const [48])) (I64Const [48])) - for { - x := v_0 - v.reset(OpWasmI64ShrS) - v0 := b.NewValue0(v.Pos, OpWasmI64Shl, typ.Int64) - v1 := b.NewValue0(v.Pos, OpWasmI64Const, typ.Int64) - v1.AuxInt = int64ToAuxInt(48) - v0.AddArg2(x, v1) - v.AddArg2(v0, v1) - return true - } } func rewriteValueWasm_OpSignExt32to64(v *Value) bool { v_0 := v.Args[0] - b := v.Block - typ := &b.Func.Config.Types // match: (SignExt32to64 x:(I64Load32S _ _)) // result: x for { @@ -3293,34 +3254,16 @@ func rewriteValueWasm_OpSignExt32to64(v *Value) bool { return true } // match: (SignExt32to64 x) - // cond: buildcfg.GOWASM.SignExt // result: (I64Extend32S x) for { x := v_0 - if !(buildcfg.GOWASM.SignExt) { - break - } v.reset(OpWasmI64Extend32S) v.AddArg(x) return true } - // match: (SignExt32to64 x) - // result: (I64ShrS (I64Shl x (I64Const [32])) (I64Const [32])) - for { - x := v_0 - v.reset(OpWasmI64ShrS) - v0 := b.NewValue0(v.Pos, OpWasmI64Shl, typ.Int64) - v1 := b.NewValue0(v.Pos, OpWasmI64Const, typ.Int64) - v1.AuxInt = int64ToAuxInt(32) - v0.AddArg2(x, v1) - v.AddArg2(v0, v1) - return true - } } func rewriteValueWasm_OpSignExt8to16(v *Value) bool { v_0 := v.Args[0] - b := v.Block - typ := &b.Func.Config.Types // match: (SignExt8to16 x:(I64Load8S _ _)) // result: x for { @@ -3332,34 +3275,16 @@ func rewriteValueWasm_OpSignExt8to16(v *Value) bool { return true } // match: (SignExt8to16 x) - // cond: buildcfg.GOWASM.SignExt // result: (I64Extend8S x) for { x := v_0 - if !(buildcfg.GOWASM.SignExt) { - break - } v.reset(OpWasmI64Extend8S) v.AddArg(x) return true } - // match: (SignExt8to16 x) - // result: (I64ShrS (I64Shl x (I64Const [56])) (I64Const [56])) - for { - x := v_0 - v.reset(OpWasmI64ShrS) - v0 := b.NewValue0(v.Pos, OpWasmI64Shl, typ.Int64) - v1 := b.NewValue0(v.Pos, OpWasmI64Const, typ.Int64) - v1.AuxInt = int64ToAuxInt(56) - v0.AddArg2(x, v1) - v.AddArg2(v0, v1) - return true - } } func rewriteValueWasm_OpSignExt8to32(v *Value) bool { v_0 := v.Args[0] - b := v.Block - typ := &b.Func.Config.Types // match: (SignExt8to32 x:(I64Load8S _ _)) // result: x for { @@ -3371,34 +3296,16 @@ func rewriteValueWasm_OpSignExt8to32(v *Value) bool { return true } // match: (SignExt8to32 x) - // cond: buildcfg.GOWASM.SignExt // result: (I64Extend8S x) for { x := v_0 - if !(buildcfg.GOWASM.SignExt) { - break - } v.reset(OpWasmI64Extend8S) v.AddArg(x) return true } - // match: (SignExt8to32 x) - // result: (I64ShrS (I64Shl x (I64Const [56])) (I64Const [56])) - for { - x := v_0 - v.reset(OpWasmI64ShrS) - v0 := b.NewValue0(v.Pos, OpWasmI64Shl, typ.Int64) - v1 := b.NewValue0(v.Pos, OpWasmI64Const, typ.Int64) - v1.AuxInt = int64ToAuxInt(56) - v0.AddArg2(x, v1) - v.AddArg2(v0, v1) - return true - } } func rewriteValueWasm_OpSignExt8to64(v *Value) bool { v_0 := v.Args[0] - b := v.Block - typ := &b.Func.Config.Types // match: (SignExt8to64 x:(I64Load8S _ _)) // result: x for { @@ -3410,29 +3317,13 @@ func rewriteValueWasm_OpSignExt8to64(v *Value) bool { return true } // match: (SignExt8to64 x) - // cond: buildcfg.GOWASM.SignExt // result: (I64Extend8S x) for { x := v_0 - if !(buildcfg.GOWASM.SignExt) { - break - } v.reset(OpWasmI64Extend8S) v.AddArg(x) return true } - // match: (SignExt8to64 x) - // result: (I64ShrS (I64Shl x (I64Const [56])) (I64Const [56])) - for { - x := v_0 - v.reset(OpWasmI64ShrS) - v0 := b.NewValue0(v.Pos, OpWasmI64Shl, typ.Int64) - v1 := b.NewValue0(v.Pos, OpWasmI64Const, typ.Int64) - v1.AuxInt = int64ToAuxInt(56) - v0.AddArg2(x, v1) - v.AddArg2(v0, v1) - return true - } } func rewriteValueWasm_OpSlicemask(v *Value) bool { v_0 := v.Args[0] diff --git a/src/cmd/compile/internal/wasm/ssa.go b/src/cmd/compile/internal/wasm/ssa.go index daee82f1fd7366..1e3b318e8c9fe0 100644 --- a/src/cmd/compile/internal/wasm/ssa.go +++ b/src/cmd/compile/internal/wasm/ssa.go @@ -14,7 +14,6 @@ import ( "cmd/compile/internal/types" "cmd/internal/obj" "cmd/internal/obj/wasm" - "internal/buildcfg" ) /* @@ -425,27 +424,11 @@ func ssaGenValueOnStack(s *ssagen.State, v *ssa.Value, extend bool) { case ssa.OpWasmI64TruncSatF32S, ssa.OpWasmI64TruncSatF64S: getValue64(s, v.Args[0]) - if buildcfg.GOWASM.SatConv { - s.Prog(v.Op.Asm()) - } else { - if v.Op == ssa.OpWasmI64TruncSatF32S { - s.Prog(wasm.AF64PromoteF32) - } - p := s.Prog(wasm.ACall) - p.To = obj.Addr{Type: obj.TYPE_MEM, Name: obj.NAME_EXTERN, Sym: ir.Syms.WasmTruncS} - } + s.Prog(v.Op.Asm()) case ssa.OpWasmI64TruncSatF32U, ssa.OpWasmI64TruncSatF64U: getValue64(s, v.Args[0]) - if buildcfg.GOWASM.SatConv { - s.Prog(v.Op.Asm()) - } else { - if v.Op == ssa.OpWasmI64TruncSatF32U { - s.Prog(wasm.AF64PromoteF32) - } - p := s.Prog(wasm.ACall) - p.To = obj.Addr{Type: obj.TYPE_MEM, Name: obj.NAME_EXTERN, Sym: ir.Syms.WasmTruncU} - } + s.Prog(v.Op.Asm()) case ssa.OpWasmF32DemoteF64: getValue64(s, v.Args[0]) diff --git a/src/internal/buildcfg/cfg.go b/src/internal/buildcfg/cfg.go index 9ab29568d22704..a75960b8e6c034 100644 --- a/src/internal/buildcfg/cfg.go +++ b/src/internal/buildcfg/cfg.go @@ -321,18 +321,13 @@ func goriscv64() int { } type gowasmFeatures struct { - SatConv bool - SignExt bool + // Legacy features, now always enabled + //SatConv bool + //SignExt bool } func (f gowasmFeatures) String() string { var flags []string - if f.SatConv { - flags = append(flags, "satconv") - } - if f.SignExt { - flags = append(flags, "signext") - } return strings.Join(flags, ",") } @@ -340,9 +335,9 @@ func gowasm() (f gowasmFeatures) { for opt := range strings.SplitSeq(envOr("GOWASM", ""), ",") { switch opt { case "satconv": - f.SatConv = true + // ignore, always enabled case "signext": - f.SignExt = true + // ignore, always enabled case "": // ignore default: @@ -452,12 +447,10 @@ func gogoarchTags() []string { return list case "wasm": var list []string - if GOWASM.SatConv { - list = append(list, GOARCH+".satconv") - } - if GOWASM.SignExt { - list = append(list, GOARCH+".signext") - } + // SatConv is always enabled + list = append(list, GOARCH+".satconv") + // SignExt is always enabled + list = append(list, GOARCH+".signext") return list } return nil diff --git a/src/runtime/conv_wasm_test.go b/src/runtime/conv_wasm_test.go index 5054fca04dc40a..3979a7b618028b 100644 --- a/src/runtime/conv_wasm_test.go +++ b/src/runtime/conv_wasm_test.go @@ -11,6 +11,8 @@ import ( var res int64 var ures uint64 +// TODO: This test probably should be in a different place. + func TestFloatTruncation(t *testing.T) { testdata := []struct { input float64 @@ -21,36 +23,37 @@ func TestFloatTruncation(t *testing.T) { // max +- 1 { input: 0x7fffffffffffffff, - convInt64: -0x8000000000000000, + convInt64: 0x7fffffffffffffff, convUInt64: 0x8000000000000000, }, // For out-of-bounds conversion, the result is implementation-dependent. - // This test verifies the implementation of wasm architecture. + // This test verifies the implementation of wasm architecture, which is, + // saturating to the min/max value. { input: 0x8000000000000000, - convInt64: -0x8000000000000000, + convInt64: 0x7fffffffffffffff, convUInt64: 0x8000000000000000, }, { input: 0x7ffffffffffffffe, - convInt64: -0x8000000000000000, + convInt64: 0x7fffffffffffffff, convUInt64: 0x8000000000000000, }, // neg max +- 1 { input: -0x8000000000000000, convInt64: -0x8000000000000000, - convUInt64: 0x8000000000000000, + convUInt64: 0, }, { input: -0x8000000000000001, convInt64: -0x8000000000000000, - convUInt64: 0x8000000000000000, + convUInt64: 0, }, { input: -0x7fffffffffffffff, convInt64: -0x8000000000000000, - convUInt64: 0x8000000000000000, + convUInt64: 0, }, // trunc point +- 1 { @@ -60,7 +63,7 @@ func TestFloatTruncation(t *testing.T) { }, { input: 0x7ffffffffffffe00, - convInt64: -0x8000000000000000, + convInt64: 0x7fffffffffffffff, convUInt64: 0x8000000000000000, }, { @@ -72,48 +75,48 @@ func TestFloatTruncation(t *testing.T) { { input: -0x7ffffffffffffdff, convInt64: -0x7ffffffffffffc00, - convUInt64: 0x8000000000000000, + convUInt64: 0, }, { input: -0x7ffffffffffffe00, convInt64: -0x8000000000000000, - convUInt64: 0x8000000000000000, + convUInt64: 0, }, { input: -0x7ffffffffffffdfe, convInt64: -0x7ffffffffffffc00, - convUInt64: 0x8000000000000000, + convUInt64: 0, }, // umax +- 1 { input: 0xffffffffffffffff, - convInt64: -0x8000000000000000, - convUInt64: 0x8000000000000000, + convInt64: 0x7fffffffffffffff, + convUInt64: 0xffffffffffffffff, }, { input: 0x10000000000000000, - convInt64: -0x8000000000000000, - convUInt64: 0x8000000000000000, + convInt64: 0x7fffffffffffffff, + convUInt64: 0xffffffffffffffff, }, { input: 0xfffffffffffffffe, - convInt64: -0x8000000000000000, - convUInt64: 0x8000000000000000, + convInt64: 0x7fffffffffffffff, + convUInt64: 0xffffffffffffffff, }, // umax trunc +- 1 { input: 0xfffffffffffffbff, - convInt64: -0x8000000000000000, + convInt64: 0x7fffffffffffffff, convUInt64: 0xfffffffffffff800, }, { input: 0xfffffffffffffc00, - convInt64: -0x8000000000000000, - convUInt64: 0x8000000000000000, + convInt64: 0x7fffffffffffffff, + convUInt64: 0xffffffffffffffff, }, { input: 0xfffffffffffffbfe, - convInt64: -0x8000000000000000, + convInt64: 0x7fffffffffffffff, convUInt64: 0xfffffffffffff800, }, } diff --git a/src/runtime/sys_wasm.s b/src/runtime/sys_wasm.s index b7965ec3fa4138..95c162eb857ac4 100644 --- a/src/runtime/sys_wasm.s +++ b/src/runtime/sys_wasm.s @@ -22,64 +22,6 @@ TEXT runtime·wasmDiv(SB), NOSPLIT, $0-0 I64DivS Return -TEXT runtime·wasmTruncS(SB), NOSPLIT, $0-0 - Get R0 - Get R0 - F64Ne // NaN - If - I64Const $0x8000000000000000 - Return - End - - Get R0 - F64Const $0x7ffffffffffffc00p0 // Maximum truncated representation of 0x7fffffffffffffff - F64Gt - If - I64Const $0x8000000000000000 - Return - End - - Get R0 - F64Const $-0x7ffffffffffffc00p0 // Minimum truncated representation of -0x8000000000000000 - F64Lt - If - I64Const $0x8000000000000000 - Return - End - - Get R0 - I64TruncF64S - Return - -TEXT runtime·wasmTruncU(SB), NOSPLIT, $0-0 - Get R0 - Get R0 - F64Ne // NaN - If - I64Const $0x8000000000000000 - Return - End - - Get R0 - F64Const $0xfffffffffffff800p0 // Maximum truncated representation of 0xffffffffffffffff - F64Gt - If - I64Const $0x8000000000000000 - Return - End - - Get R0 - F64Const $0. - F64Lt - If - I64Const $0x8000000000000000 - Return - End - - Get R0 - I64TruncF64U - Return - TEXT runtime·exitThread(SB), NOSPLIT, $0-0 UNDEF From 6e95748335bdd074c5b48fe9c3af4ced18c388dd Mon Sep 17 00:00:00 2001 From: qmuntal Date: Fri, 12 Sep 2025 16:23:40 +0200 Subject: [PATCH 017/229] cmd/link/internal/arm64: support Mach-O ARM64_RELOC_POINTER_TO_GOT in internal linking ARM64_RELOC_POINTER_TO_GOT is the arm64 version of X86_64_RELOC_GOT, which has been support for many years now. The standard library still doesn't need it, but I've found it necessary when statically linking against a library I own. Change-Id: I8eb7bf3c74aed663a1fc00b5dd986057130f7f7a Reviewed-on: https://go-review.googlesource.com/c/go/+/703315 LUCI-TryBot-Result: Go LUCI Reviewed-by: Carlos Amedee Reviewed-by: Cherry Mui --- src/cmd/link/internal/arm64/asm.go | 11 +++++++++++ src/cmd/link/internal/ld/macho.go | 1 + 2 files changed, 12 insertions(+) diff --git a/src/cmd/link/internal/arm64/asm.go b/src/cmd/link/internal/arm64/asm.go index 68474b4484f1af..b2572fd1040b0b 100644 --- a/src/cmd/link/internal/arm64/asm.go +++ b/src/cmd/link/internal/arm64/asm.go @@ -277,6 +277,17 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade su.SetRelocSym(rIdx, syms.GOT) su.SetRelocAdd(rIdx, int64(ldr.SymGot(targ))) return true + + case objabi.MachoRelocOffset + ld.MACHO_ARM64_RELOC_POINTER_TO_GOT*2 + pcrel: + if targType != sym.SDYNIMPORT { + ldr.Errorf(s, "unexpected GOT reloc for non-dynamic symbol %s", ldr.SymName(targ)) + } + ld.AddGotSym(target, ldr, syms, targ, 0) + su := ldr.MakeSymbolUpdater(s) + su.SetRelocType(rIdx, objabi.R_PCREL) + su.SetRelocSym(rIdx, syms.GOT) + su.SetRelocAdd(rIdx, r.Add()+int64(r.Siz())+int64(ldr.SymGot(targ))) + return true } // Reread the reloc to incorporate any changes in type above. diff --git a/src/cmd/link/internal/ld/macho.go b/src/cmd/link/internal/ld/macho.go index 431dad9d6bcbaa..6920f42015b344 100644 --- a/src/cmd/link/internal/ld/macho.go +++ b/src/cmd/link/internal/ld/macho.go @@ -111,6 +111,7 @@ const ( MACHO_ARM64_RELOC_PAGEOFF12 = 4 MACHO_ARM64_RELOC_GOT_LOAD_PAGE21 = 5 MACHO_ARM64_RELOC_GOT_LOAD_PAGEOFF12 = 6 + MACHO_ARM64_RELOC_POINTER_TO_GOT = 7 MACHO_ARM64_RELOC_ADDEND = 10 MACHO_GENERIC_RELOC_VANILLA = 0 MACHO_FAKE_GOTPCREL = 100 From 7c8166d02d36a5dfcdbe3dd1b148412cceacf9f2 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Fri, 12 Sep 2025 16:31:01 +0200 Subject: [PATCH 018/229] cmd/link/internal/arm64: support Mach-O ARM64_RELOC_SUBTRACTOR in internal linking ARM64_RELOC_SUBTRACTOR is the arm64 version of X86_64_RELOC_SUBTRACTOR, which has been recently implemented in CL 660715. The standard library still doesn't need it, but I've found it necessary when statically linking against a library I own. Change-Id: I138281b12f2304e3673f7dc92f7137e48bf68fdd Reviewed-on: https://go-review.googlesource.com/c/go/+/703316 Reviewed-by: Carlos Amedee LUCI-TryBot-Result: Go LUCI Reviewed-by: Cherry Mui --- src/cmd/link/internal/arm64/asm.go | 22 ++++++++++++++++++++++ src/cmd/link/internal/ld/macho.go | 1 + 2 files changed, 23 insertions(+) diff --git a/src/cmd/link/internal/arm64/asm.go b/src/cmd/link/internal/arm64/asm.go index b2572fd1040b0b..8d8ea8ac542c50 100644 --- a/src/cmd/link/internal/arm64/asm.go +++ b/src/cmd/link/internal/arm64/asm.go @@ -224,6 +224,28 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade } return true + case objabi.MachoRelocOffset + ld.MACHO_ARM64_RELOC_SUBTRACTOR*2: + // ARM64_RELOC_SUBTRACTOR must be followed by ARM64_RELOC_UNSIGNED. + // The pair of relocations resolves to the difference between two + // symbol addresses (each relocation specifies a symbol). + outer, off := ld.FoldSubSymbolOffset(ldr, targ) + if outer != s { + // TODO: support subtracted symbol in different section. + ldr.Errorf(s, "unsupported ARM64_RELOC_SUBTRACTOR reloc: target %s, outer %s", ldr.SymName(targ), ldr.SymName(outer)) + break + } + su := ldr.MakeSymbolUpdater(s) + relocs := su.Relocs() + if rIdx+1 >= relocs.Count() || relocs.At(rIdx+1).Type() != objabi.MachoRelocOffset+ld.MACHO_ARM64_RELOC_UNSIGNED*2 || relocs.At(rIdx+1).Off() != r.Off() { + ldr.Errorf(s, "unexpected ARM64_RELOC_SUBTRACTOR reloc, must be followed by ARM64_RELOC_UNSIGNED at same offset") + break + } + su.SetRelocType(rIdx+1, objabi.R_PCREL) + su.SetRelocAdd(rIdx+1, r.Add()+int64(r.Off())+int64(r.Siz())-off) + // Remove the other relocation + su.SetRelocSiz(rIdx, 0) + return true + case objabi.MachoRelocOffset + ld.MACHO_ARM64_RELOC_BRANCH26*2 + pcrel: su := ldr.MakeSymbolUpdater(s) su.SetRelocType(rIdx, objabi.R_CALLARM64) diff --git a/src/cmd/link/internal/ld/macho.go b/src/cmd/link/internal/ld/macho.go index 6920f42015b344..c26263466616f5 100644 --- a/src/cmd/link/internal/ld/macho.go +++ b/src/cmd/link/internal/ld/macho.go @@ -106,6 +106,7 @@ const ( MACHO_ARM_RELOC_SECTDIFF = 2 MACHO_ARM_RELOC_BR24 = 5 MACHO_ARM64_RELOC_UNSIGNED = 0 + MACHO_ARM64_RELOC_SUBTRACTOR = 1 MACHO_ARM64_RELOC_BRANCH26 = 2 MACHO_ARM64_RELOC_PAGE21 = 3 MACHO_ARM64_RELOC_PAGEOFF12 = 4 From a846bb0aa523c8781248161b63bc2ab6a245cec1 Mon Sep 17 00:00:00 2001 From: Julien Cretel Date: Mon, 29 Sep 2025 16:57:53 +0000 Subject: [PATCH 019/229] errors: add AsType Fixes #51945 Change-Id: Icda169782e796578eba728938134a85b5827d3b6 GitHub-Last-Rev: c6ff335ee1ffb6b7975141795a4632a55247299d GitHub-Pull-Request: golang/go#75621 Reviewed-on: https://go-review.googlesource.com/c/go/+/707235 Reviewed-by: Carlos Amedee Reviewed-by: Damien Neil LUCI-TryBot-Result: Go LUCI Reviewed-by: Sean Liao --- api/next/51945.txt | 1 + doc/next/6-stdlib/99-minor/errors/51945.md | 2 + src/errors/errors.go | 10 +- src/errors/example_test.go | 12 ++ src/errors/wrap.go | 61 ++++++++++ src/errors/wrap_test.go | 126 +++++++++++++++++++++ 6 files changed, 207 insertions(+), 5 deletions(-) create mode 100644 api/next/51945.txt create mode 100644 doc/next/6-stdlib/99-minor/errors/51945.md diff --git a/api/next/51945.txt b/api/next/51945.txt new file mode 100644 index 00000000000000..7db1f093e5a2a5 --- /dev/null +++ b/api/next/51945.txt @@ -0,0 +1 @@ +pkg errors, func AsType[$0 error](error) ($0, bool) #51945 diff --git a/doc/next/6-stdlib/99-minor/errors/51945.md b/doc/next/6-stdlib/99-minor/errors/51945.md new file mode 100644 index 00000000000000..44ac7222e6d990 --- /dev/null +++ b/doc/next/6-stdlib/99-minor/errors/51945.md @@ -0,0 +1,2 @@ +The new [AsType] function is a generic version of [As]. It is type-safe, faster, +and, in most cases, easier to use. diff --git a/src/errors/errors.go b/src/errors/errors.go index 5059be12ed441f..8b926cfe148c44 100644 --- a/src/errors/errors.go +++ b/src/errors/errors.go @@ -41,12 +41,12 @@ // // because the former will succeed if err wraps [io/fs.ErrExist]. // -// [As] examines the tree of its first argument looking for an error that can be -// assigned to its second argument, which must be a pointer. If it succeeds, it -// performs the assignment and returns true. Otherwise, it returns false. The form +// [AsType] examines the tree of its argument looking for an error whose +// type matches its type argument. If it succeeds, it returns the +// corresponding value of that type and true. Otherwise, it returns the +// zero value of that type and false. The form // -// var perr *fs.PathError -// if errors.As(err, &perr) { +// if perr, ok := errors.AsType[*fs.PathError](err); ok { // fmt.Println(perr.Path) // } // diff --git a/src/errors/example_test.go b/src/errors/example_test.go index 278df8c7da6e5a..92ef36b1010edb 100644 --- a/src/errors/example_test.go +++ b/src/errors/example_test.go @@ -102,6 +102,18 @@ func ExampleAs() { // Failed at path: non-existing } +func ExampleAsType() { + if _, err := os.Open("non-existing"); err != nil { + if pathError, ok := errors.AsType[*fs.PathError](err); ok { + fmt.Println("Failed at path:", pathError.Path) + } else { + fmt.Println(err) + } + } + // Output: + // Failed at path: non-existing +} + func ExampleUnwrap() { err1 := errors.New("error1") err2 := fmt.Errorf("error2: [%w]", err1) diff --git a/src/errors/wrap.go b/src/errors/wrap.go index eec9591dae7b93..2ebb951f1de93d 100644 --- a/src/errors/wrap.go +++ b/src/errors/wrap.go @@ -80,6 +80,10 @@ func is(err, target error, targetComparable bool) bool { // As finds the first error in err's tree that matches target, and if one is found, sets // target to that error value and returns true. Otherwise, it returns false. // +// For most uses, prefer [AsType]. As is equivalent to [AsType] but sets its target +// argument rather than returning the matching error and doesn't require its target +// argument to implement error. +// // The tree consists of err itself, followed by the errors obtained by repeatedly // calling its Unwrap() error or Unwrap() []error method. When err wraps multiple // errors, As examines err followed by a depth-first traversal of its children. @@ -145,3 +149,60 @@ func as(err error, target any, targetVal reflectlite.Value, targetType reflectli } var errorType = reflectlite.TypeOf((*error)(nil)).Elem() + +// AsType finds the first error in err's tree that matches the type E, and +// if one is found, returns that error value and true. Otherwise, it +// returns the zero value of E and false. +// +// The tree consists of err itself, followed by the errors obtained by +// repeatedly calling its Unwrap() error or Unwrap() []error method. When +// err wraps multiple errors, AsType examines err followed by a +// depth-first traversal of its children. +// +// An error err matches the type E if the type assertion err.(E) holds, +// or if the error has a method As(any) bool such that err.As(target) +// returns true when target is a non-nil *E. In the latter case, the As +// method is responsible for setting target. +func AsType[E error](err error) (E, bool) { + if err == nil { + var zero E + return zero, false + } + var pe *E // lazily initialized + return asType(err, &pe) +} + +func asType[E error](err error, ppe **E) (_ E, _ bool) { + for { + if e, ok := err.(E); ok { + return e, true + } + if x, ok := err.(interface{ As(any) bool }); ok { + if *ppe == nil { + *ppe = new(E) + } + if x.As(*ppe) { + return **ppe, true + } + } + switch x := err.(type) { + case interface{ Unwrap() error }: + err = x.Unwrap() + if err == nil { + return + } + case interface{ Unwrap() []error }: + for _, err := range x.Unwrap() { + if err == nil { + continue + } + if x, ok := asType(err, ppe); ok { + return x, true + } + } + return + default: + return + } + } +} diff --git a/src/errors/wrap_test.go b/src/errors/wrap_test.go index 58ed95fd9a0fc7..81c795a6bb8b18 100644 --- a/src/errors/wrap_test.go +++ b/src/errors/wrap_test.go @@ -239,6 +239,123 @@ func TestAsValidation(t *testing.T) { } } +func TestAsType(t *testing.T) { + var errT errorT + var errP *fs.PathError + type timeout interface { + Timeout() bool + error + } + _, errF := os.Open("non-existing") + poserErr := &poser{"oh no", nil} + + testAsType(t, + nil, + errP, + false, + ) + testAsType(t, + wrapped{"pitied the fool", errorT{"T"}}, + errorT{"T"}, + true, + ) + testAsType(t, + errF, + errF, + true, + ) + testAsType(t, + errT, + errP, + false, + ) + testAsType(t, + wrapped{"wrapped", nil}, + errT, + false, + ) + testAsType(t, + &poser{"error", nil}, + errorT{"poser"}, + true, + ) + testAsType(t, + &poser{"path", nil}, + poserPathErr, + true, + ) + testAsType(t, + poserErr, + poserErr, + true, + ) + testAsType(t, + errors.New("err"), + timeout(nil), + false, + ) + testAsType(t, + errF, + errF.(timeout), + true) + testAsType(t, + wrapped{"path error", errF}, + errF.(timeout), + true, + ) + testAsType(t, + multiErr{}, + errT, + false, + ) + testAsType(t, + multiErr{errors.New("a"), errorT{"T"}}, + errorT{"T"}, + true, + ) + testAsType(t, + multiErr{errorT{"T"}, errors.New("a")}, + errorT{"T"}, + true, + ) + testAsType(t, + multiErr{errorT{"a"}, errorT{"b"}}, + errorT{"a"}, + true, + ) + testAsType(t, + multiErr{multiErr{errors.New("a"), errorT{"a"}}, errorT{"b"}}, + errorT{"a"}, + true, + ) + testAsType(t, + multiErr{wrapped{"path error", errF}}, + errF.(timeout), + true, + ) + testAsType(t, + multiErr{nil}, + errT, + false, + ) +} + +type compError interface { + comparable + error +} + +func testAsType[E compError](t *testing.T, err error, want E, wantOK bool) { + t.Helper() + name := fmt.Sprintf("AsType[%T](Errorf(..., %v))", want, err) + t.Run(name, func(t *testing.T) { + got, gotOK := errors.AsType[E](err) + if gotOK != wantOK || got != want { + t.Fatalf("got %v, %t; want %v, %t", got, gotOK, want, wantOK) + } + }) +} + func BenchmarkIs(b *testing.B) { err1 := errors.New("1") err2 := multiErr{multiErr{multiErr{err1, errorT{"a"}}, errorT{"b"}}} @@ -260,6 +377,15 @@ func BenchmarkAs(b *testing.B) { } } +func BenchmarkAsType(b *testing.B) { + err := multiErr{multiErr{multiErr{errors.New("a"), errorT{"a"}}, errorT{"b"}}} + for range b.N { + if _, ok := errors.AsType[errorT](err); !ok { + b.Fatal("AsType failed") + } + } +} + func TestUnwrap(t *testing.T) { err1 := errors.New("1") erra := wrapped{"wrap 2", err1} From 300d9d2714164e455abc7990d52de9de6b084df1 Mon Sep 17 00:00:00 2001 From: Steve Muir Date: Thu, 18 Sep 2025 07:54:57 -0700 Subject: [PATCH 020/229] runtime: initialise debug settings much earlier in startup process This is necessary specifically to set the value of `debug.decoratemappings` sufficiently early in the startup sequence that all memory ranges allocated can be named appropriately using the new Linux-specific naming API introduced in #71546. Example output (on ARM64): https://gist.github.com/9muir/3667654b9c3f52e8be92756219371672 Fixes: #75324 Change-Id: Ic0b16233f54a45adef1660c4d0df59af2f5af86a Reviewed-on: https://go-review.googlesource.com/c/go/+/703476 Auto-Submit: Michael Knyszek LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Knyszek --- src/runtime/decoratemappings_test.go | 72 ++++++++++++++++++++++++++++ src/runtime/export_test.go | 4 ++ src/runtime/proc.go | 24 ++++++++-- src/runtime/runtime1.go | 15 +++--- src/runtime/set_vma_name_linux.go | 6 ++- src/runtime/set_vma_name_stub.go | 2 + 6 files changed, 109 insertions(+), 14 deletions(-) create mode 100644 src/runtime/decoratemappings_test.go diff --git a/src/runtime/decoratemappings_test.go b/src/runtime/decoratemappings_test.go new file mode 100644 index 00000000000000..7d1121c125df08 --- /dev/null +++ b/src/runtime/decoratemappings_test.go @@ -0,0 +1,72 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package runtime_test + +import ( + "os" + "regexp" + "runtime" + "testing" +) + +func validateMapLabels(t *testing.T, labels []string) { + // These are the specific region labels that need get added during the + // runtime phase. Hence they are the ones that need to be confirmed as + // present at the time the test reads its own region labels, which + // is sufficient to validate that the default `decoratemappings` value + // (enabled) was set early enough in the init process. + regions := map[string]bool{ + "allspans array": false, + "gc bits": false, + "heap": false, + "heap index": false, + "heap reservation": false, + "immortal metadata": false, + "page alloc": false, + "page alloc index": false, + "page summary": false, + "scavenge index": false, + } + for _, label := range labels { + if _, ok := regions[label]; !ok { + t.Logf("unexpected region label found: \"%s\"", label) + } + regions[label] = true + } + for label, found := range regions { + if !found { + t.Logf("region label missing: \"%s\"", label) + } + } +} + +func TestDecorateMappings(t *testing.T) { + if runtime.GOOS != "linux" { + t.Skip("decoratemappings is only supported on Linux") + // /proc/self/maps is also Linux-specific + } + + var labels []string + if rawMaps, err := os.ReadFile("/proc/self/maps"); err != nil { + t.Fatalf("failed to read /proc/self/maps: %v", err) + } else { + t.Logf("maps:%s\n", string(rawMaps)) + matches := regexp.MustCompile("[^[]+ \\[anon: Go: (.+)\\]\n").FindAllSubmatch(rawMaps, -1) + for _, match_pair := range matches { + // match_pair consists of the matching substring and the parenthesized group + labels = append(labels, string(match_pair[1])) + } + } + t.Logf("DebugDecorateMappings: %v", *runtime.DebugDecorateMappings) + if *runtime.DebugDecorateMappings != 0 && runtime.SetVMANameSupported() { + validateMapLabels(t, labels) + } else { + if len(labels) > 0 { + t.Errorf("unexpected mapping labels present: %v", labels) + } else { + t.Skip("mapping labels absent as expected") + } + } +} diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go index 2a701115685411..9f2fcacc30ee5c 100644 --- a/src/runtime/export_test.go +++ b/src/runtime/export_test.go @@ -1936,3 +1936,7 @@ func (t *TraceStackTable) Reset() { func TraceStack(gp *G, tab *TraceStackTable) { traceStack(0, gp, (*traceStackTable)(tab)) } + +var DebugDecorateMappings = &debug.decoratemappings + +func SetVMANameSupported() bool { return setVMANameSupported() } diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 2c42cad6c10e8a..4b1ab1af6a5075 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -789,7 +789,9 @@ func cpuinit(env string) { // getGodebugEarly extracts the environment variable GODEBUG from the environment on // Unix-like operating systems and returns it. This function exists to extract GODEBUG // early before much of the runtime is initialized. -func getGodebugEarly() string { +// +// Returns nil, false if OS doesn't provide env vars early in the init sequence. +func getGodebugEarly() (string, bool) { const prefix = "GODEBUG=" var env string switch GOOS { @@ -807,12 +809,16 @@ func getGodebugEarly() string { s := unsafe.String(p, findnull(p)) if stringslite.HasPrefix(s, prefix) { - env = gostring(p)[len(prefix):] + env = gostringnocopy(p)[len(prefix):] break } } + break + + default: + return "", false } - return env + return env, true } // The bootstrap sequence is: @@ -859,12 +865,15 @@ func schedinit() { // The world starts stopped. worldStopped() + godebug, parsedGodebug := getGodebugEarly() + if parsedGodebug { + parseRuntimeDebugVars(godebug) + } ticks.init() // run as early as possible moduledataverify() stackinit() randinit() // must run before mallocinit, alginit, mcommoninit mallocinit() - godebug := getGodebugEarly() cpuinit(godebug) // must run before alginit alginit() // maps, hash, rand must not be used before this call mcommoninit(gp.m, -1) @@ -880,7 +889,12 @@ func schedinit() { goenvs() secure() checkfds() - parsedebugvars() + if !parsedGodebug { + // Some platforms, e.g., Windows, didn't make env vars available "early", + // so try again now. + parseRuntimeDebugVars(gogetenv("GODEBUG")) + } + finishDebugVarsSetup() gcinit() // Allocate stack space that can be used when crashing due to bad stack diff --git a/src/runtime/runtime1.go b/src/runtime/runtime1.go index 424745d2357dc9..15b546783b5e53 100644 --- a/src/runtime/runtime1.go +++ b/src/runtime/runtime1.go @@ -402,7 +402,7 @@ var dbgvars = []*dbgVar{ {name: "updatemaxprocs", value: &debug.updatemaxprocs, def: 1}, } -func parsedebugvars() { +func parseRuntimeDebugVars(godebug string) { // defaults debug.cgocheck = 1 debug.invalidptr = 1 @@ -420,12 +420,6 @@ func parsedebugvars() { } debug.traceadvanceperiod = defaultTraceAdvancePeriod - godebug := gogetenv("GODEBUG") - - p := new(string) - *p = godebug - godebugEnv.Store(p) - // apply runtime defaults, if any for _, v := range dbgvars { if v.def != 0 { @@ -437,7 +431,6 @@ func parsedebugvars() { } } } - // apply compile-time GODEBUG settings parsegodebug(godebugDefault, nil) @@ -463,6 +456,12 @@ func parsedebugvars() { if debug.gccheckmark > 0 { debug.asyncpreemptoff = 1 } +} + +func finishDebugVarsSetup() { + p := new(string) + *p = gogetenv("GODEBUG") + godebugEnv.Store(p) setTraceback(gogetenv("GOTRACEBACK")) traceback_env = traceback_cache diff --git a/src/runtime/set_vma_name_linux.go b/src/runtime/set_vma_name_linux.go index 9b6654f33299a0..03c7739c3465c9 100644 --- a/src/runtime/set_vma_name_linux.go +++ b/src/runtime/set_vma_name_linux.go @@ -14,9 +14,13 @@ import ( var prSetVMAUnsupported atomic.Bool +func setVMANameSupported() bool { + return !prSetVMAUnsupported.Load() +} + // setVMAName calls prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, name) func setVMAName(start unsafe.Pointer, length uintptr, name string) { - if debug.decoratemappings == 0 || prSetVMAUnsupported.Load() { + if debug.decoratemappings == 0 || !setVMANameSupported() { return } diff --git a/src/runtime/set_vma_name_stub.go b/src/runtime/set_vma_name_stub.go index 38f65fd592ba34..6cb01ebf50dcef 100644 --- a/src/runtime/set_vma_name_stub.go +++ b/src/runtime/set_vma_name_stub.go @@ -10,3 +10,5 @@ import "unsafe" // setVMAName isn’t implemented func setVMAName(start unsafe.Pointer, len uintptr, name string) {} + +func setVMANameSupported() bool { return false } From 97da068774d5aa9147e63eb146350145c73bfc3d Mon Sep 17 00:00:00 2001 From: Jake Bailey Date: Sun, 7 Sep 2025 22:21:15 -0700 Subject: [PATCH 021/229] cmd/compile: eliminate nil checks on .dict arg The first arg of a generic function is the dictionary. This dictionary is never nil, but it gets a nil check becuase the dict arg is treated as a slice during construction. cmp.Compare[go.shape.int] was: 00006 (+41) TESTB AX, (AX) 00007 (+52) CMPQ CX, BX 00008 (52) JGT 14 00009 (+55) JGE 12 00010 (+56) MOVL $1, AX 00011 (56) RET 00012 (+58) XORL AX, AX 00013 (58) RET 00014 (+53) MOVQ $-1, AX 00015 (53) RET Note how the function begins with a TESTB that loads the dict to perform the nil check. This CL eliminates that nil check. For most generic functions, this doesn't matter too much, but not infrequently are generic functions written which never actually use the dictionary (like cmp.Compare), so I suspect this might help in hot code to avoid repeatedly touching the dictionary in memory, and in cases where the generic function is not inlined (and thus the dict dropped). compilecmp shows these changes (deduped): cmp.Compare[go.shape.float64] 73 -> 72 (-1.37%) cmp.Compare[go.shape.int] 26 -> 24 (-7.69%) cmp.Compare[go.shape.int32] 25 -> 23 (-8.00%) cmp.Compare[go.shape.int64] 26 -> 24 (-7.69%) cmp.Compare[go.shape.string] 142 -> 141 (-0.70%) cmp.Compare[go.shape.uint16] 26 -> 24 (-7.69%) cmp.Compare[go.shape.uint] 26 -> 24 (-7.69%) cmp.Compare[go.shape.uint32] 25 -> 23 (-8.00%) cmp.Compare[go.shape.uint64] 26 -> 24 (-7.69%) cmp.Compare[go.shape.uint8] 25 -> 23 (-8.00%) cmp.Compare[go.shape.uintptr] 26 -> 24 (-7.69%) cmp.Less[go.shape.float64] 35 -> 34 (-2.86%) cmp.Less[go.shape.int32] 8 -> 6 (-25.00%) cmp.Less[go.shape.int64] 9 -> 7 (-22.22%) cmp.Less[go.shape.int] 9 -> 7 (-22.22%) cmp.Less[go.shape.string] 112 -> 110 (-1.79%) cmp.Less[go.shape.uint16] 9 -> 7 (-22.22%) cmp.Less[go.shape.uint32] 8 -> 6 (-25.00%) cmp.Less[go.shape.uint64] 9 -> 7 (-22.22%) internal/synctest.Associate[go.shape.struct 114 -> 113 (-0.88%) internal/trace.(*dataTable[go.shape.uint64,go.shape.string]).insert 805 -> 791 (-1.74%) internal/trace.(*dataTable[go.shape.uint64,go.shape.struct 858 -> 852 (-0.70%) main.(*gState[go.shape.int64]).stop 2111 -> 2085 (-1.23%) main.(*gState[go.shape.int64]).unblock 941 -> 923 (-1.91%) runtime.fmax[go.shape.float32] 85 -> 83 (-2.35%) runtime.fmax[go.shape.float64] 89 -> 87 (-2.25%) runtime.fmin[go.shape.float32] 85 -> 83 (-2.35%) runtime.fmin[go.shape.float64] 89 -> 87 (-2.25%) slices.BinarySearch[go.shape.[]string,go.shape.string] 346 -> 337 (-2.60%) slices.Concat[go.shape.[]uint8,go.shape.uint8] 462 -> 453 (-1.95%) slices.ContainsFunc[go.shape.[]*cmd/vendor/github.com/google/pprof/profile.Sample,go.shape.*uint8] 170 -> 169 (-0.59%) slices.ContainsFunc[go.shape.[]*debug/dwarf.StructField,go.shape.*uint8] 170 -> 169 (-0.59%) slices.ContainsFunc[go.shape.[]*go/ast.Field,go.shape.*uint8] 170 -> 169 (-0.59%) slices.ContainsFunc[go.shape.[]string,go.shape.string] 186 -> 181 (-2.69%) slices.Contains[go.shape.[]*cmd/compile/internal/syntax.BranchStmt,go.shape.*cmd/compile/internal/syntax.BranchStmt] 44 -> 42 (-4.55%) slices.Contains[go.shape.[]cmd/compile/internal/syntax.Type,go.shape.interface 223 -> 219 (-1.79%) slices.Contains[go.shape.[]crypto/tls.CurveID,go.shape.uint16] 44 -> 42 (-4.55%) slices.Contains[go.shape.[]crypto/tls.SignatureScheme,go.shape.uint16] 44 -> 42 (-4.55%) slices.Contains[go.shape.[]*go/ast.BranchStmt,go.shape.*go/ast.BranchStmt] 44 -> 42 (-4.55%) slices.Contains[go.shape.[]go/types.Type,go.shape.interface 223 -> 219 (-1.79%) slices.Contains[go.shape.[]int,go.shape.int] 44 -> 42 (-4.55%) slices.Contains[go.shape.[]string,go.shape.string] 223 -> 219 (-1.79%) slices.Contains[go.shape.[]uint16,go.shape.uint16] 44 -> 42 (-4.55%) slices.Contains[go.shape.[]uint8,go.shape.uint8] 44 -> 42 (-4.55%) slices.Insert[go.shape.[]string,go.shape.string] 1189 -> 1170 (-1.60%) slices.medianCmpFunc[go.shape.struct 1118 -> 1113 (-0.45%) slices.medianCmpFunc[go.shape.struct 1214 -> 1209 (-0.41%) slices.medianCmpFunc[go.shape.struct 889 -> 887 (-0.22%) slices.medianCmpFunc[go.shape.struct 901 -> 874 (-3.00%) slices.order2Ordered[go.shape.float64] 89 -> 87 (-2.25%) slices.order2Ordered[go.shape.uint16] 75 -> 70 (-6.67%) slices.partialInsertionSortOrdered[go.shape.string] 1115 -> 1110 (-0.45%) slices.partialInsertionSortOrdered[go.shape.uint16] 358 -> 352 (-1.68%) slices.partitionEqualOrdered[go.shape.int] 208 -> 203 (-2.40%) slices.partitionEqualOrdered[go.shape.int32] 208 -> 198 (-4.81%) slices.partitionEqualOrdered[go.shape.int64] 208 -> 203 (-2.40%) slices.partitionEqualOrdered[go.shape.uint32] 208 -> 198 (-4.81%) slices.partitionEqualOrdered[go.shape.uint64] 208 -> 203 (-2.40%) slices.partitionOrdered[go.shape.float64] 538 -> 533 (-0.93%) slices.partitionOrdered[go.shape.int] 437 -> 427 (-2.29%) slices.partitionOrdered[go.shape.int64] 437 -> 427 (-2.29%) slices.partitionOrdered[go.shape.uint16] 447 -> 442 (-1.12%) slices.partitionOrdered[go.shape.uint64] 437 -> 427 (-2.29%) slices.rotateCmpFunc[go.shape.struct 1045 -> 1029 (-1.53%) slices.rotateCmpFunc[go.shape.struct 1205 -> 1163 (-3.49%) slices.rotateCmpFunc[go.shape.struct 1226 -> 1176 (-4.08%) slices.rotateCmpFunc[go.shape.struct 1322 -> 1272 (-3.78%) slices.rotateCmpFunc[go.shape.struct 1419 -> 1400 (-1.34%) slices.rotateCmpFunc[go.shape.*uint8] 549 -> 538 (-2.00%) slices.rotateLeft[go.shape.string] 603 -> 588 (-2.49%) slices.rotateLeft[go.shape.uint8] 255 -> 250 (-1.96%) slices.siftDownOrdered[go.shape.int] 181 -> 171 (-5.52%) slices.siftDownOrdered[go.shape.int32] 181 -> 171 (-5.52%) slices.siftDownOrdered[go.shape.int64] 181 -> 171 (-5.52%) slices.siftDownOrdered[go.shape.string] 614 -> 592 (-3.58%) slices.siftDownOrdered[go.shape.uint32] 181 -> 171 (-5.52%) slices.siftDownOrdered[go.shape.uint64] 181 -> 171 (-5.52%) time.parseRFC3339[go.shape.string] 1774 -> 1758 (-0.90%) unique.(*canonMap[go.shape.struct 280 -> 276 (-1.43%) unique.clone[go.shape.struct 311 -> 293 (-5.79%) weak.Make[go.shape.6880e4598856efac32416085c0172278cf0fb9e5050ce6518bd9b7f7d1662440] 136 -> 134 (-1.47%) weak.Make[go.shape.struct 136 -> 134 (-1.47%) weak.Make[go.shape.uint8] 136 -> 134 (-1.47%) Change-Id: I43dcea5f2aa37372f773e5edc6a2ef1dee0a8db7 Reviewed-on: https://go-review.googlesource.com/c/go/+/706655 LUCI-TryBot-Result: Go LUCI Reviewed-by: David Chase Reviewed-by: Keith Randall Reviewed-by: Keith Randall Auto-Submit: Keith Randall --- .../compile/internal/ssa/_gen/generic.rules | 3 ++ src/cmd/compile/internal/ssa/rewrite.go | 6 +++ .../compile/internal/ssa/rewritegeneric.go | 15 +++++++ test/codegen/generics.go | 40 +++++++++++++++++++ 4 files changed, 64 insertions(+) create mode 100644 test/codegen/generics.go diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules index 58872ca85a3961..b16aa473cd5961 100644 --- a/src/cmd/compile/internal/ssa/_gen/generic.rules +++ b/src/cmd/compile/internal/ssa/_gen/generic.rules @@ -2079,6 +2079,9 @@ && warnRule(fe.Debug_checknil(), v, "removed nil check") => ptr +// .dict args are always non-nil. +(NilCheck ptr:(Arg {sym}) _) && isDictArgSym(sym) => ptr + // Nil checks of nil checks are redundant. // See comment at the end of https://go-review.googlesource.com/c/go/+/537775. (NilCheck ptr:(NilCheck _ _) _ ) => ptr diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go index 6d83ba565317a3..880c2223ef2229 100644 --- a/src/cmd/compile/internal/ssa/rewrite.go +++ b/src/cmd/compile/internal/ssa/rewrite.go @@ -6,9 +6,11 @@ package ssa import ( "cmd/compile/internal/base" + "cmd/compile/internal/ir" "cmd/compile/internal/logopt" "cmd/compile/internal/reflectdata" "cmd/compile/internal/rttype" + "cmd/compile/internal/typecheck" "cmd/compile/internal/types" "cmd/internal/obj" "cmd/internal/obj/s390x" @@ -2744,3 +2746,7 @@ func panicBoundsCToAux(p PanicBoundsC) Aux { func panicBoundsCCToAux(p PanicBoundsCC) Aux { return p } + +func isDictArgSym(sym Sym) bool { + return sym.(*ir.Name).Sym().Name == typecheck.LocalDictName +} diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go index 7e23194e6aba12..5e0135be3a5be5 100644 --- a/src/cmd/compile/internal/ssa/rewritegeneric.go +++ b/src/cmd/compile/internal/ssa/rewritegeneric.go @@ -21393,6 +21393,21 @@ func rewriteValuegeneric_OpNilCheck(v *Value) bool { v.copyOf(ptr) return true } + // match: (NilCheck ptr:(Arg {sym}) _) + // cond: isDictArgSym(sym) + // result: ptr + for { + ptr := v_0 + if ptr.Op != OpArg { + break + } + sym := auxToSym(ptr.Aux) + if !(isDictArgSym(sym)) { + break + } + v.copyOf(ptr) + return true + } // match: (NilCheck ptr:(NilCheck _ _) _ ) // result: ptr for { diff --git a/test/codegen/generics.go b/test/codegen/generics.go new file mode 100644 index 00000000000000..45c4ca8d6aee61 --- /dev/null +++ b/test/codegen/generics.go @@ -0,0 +1,40 @@ +// asmcheck + +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package codegen + +import "cmp" + +func isNaN[T cmp.Ordered](x T) bool { + return x != x +} + +func compare[T cmp.Ordered](x, y T) int { + // amd64:-"TESTB" + // arm64:-"MOVB" + xNaN := isNaN(x) + yNaN := isNaN(y) + if xNaN { + if yNaN { + return 0 + } + return -1 + } + if yNaN { + return +1 + } + if x < y { + return -1 + } + if x > y { + return +1 + } + return 0 +} + +func usesCompare(a, b int) int { + return compare(a, b) +} From 08afc50bea9a94e86adfc8cd852c6ae5b698cdaa Mon Sep 17 00:00:00 2001 From: Aidan Welch Date: Thu, 25 Sep 2025 21:00:45 +0000 Subject: [PATCH 022/229] mime: extend "builtinTypes" to include a more complete list of common types Implement all agreed upon types, using IANA's listed media types to decide when there is a disagreement in type. Except in the case of `.wav` where `audio/wav` is used. Fixes #69530 Change-Id: Iec99a6ceb534073be83c8390f48799bec3e4cfc7 GitHub-Last-Rev: e314c5ec6d9aba753dca5f6dbb9d1741bac43227 GitHub-Pull-Request: golang/go#69533 Reviewed-on: https://go-review.googlesource.com/c/go/+/614376 Reviewed-by: Damien Neil Reviewed-by: Emmanuel Odeke Auto-Submit: Sean Liao Reviewed-by: Sean Liao LUCI-TryBot-Result: Go LUCI Reviewed-by: Carlos Amedee --- src/mime/type.go | 93 +++++++++++++++++++++++++++++++++++-------- src/mime/type_test.go | 46 ++++++++++++++++++++- 2 files changed, 121 insertions(+), 18 deletions(-) diff --git a/src/mime/type.go b/src/mime/type.go index c86ebd3442c1dc..ac7b0447da3cf9 100644 --- a/src/mime/type.go +++ b/src/mime/type.go @@ -17,7 +17,7 @@ var ( mimeTypesLower sync.Map // map[string]string; ".z" => "application/x-compress" // extensions maps from MIME type to list of lowercase file - // extensions: "image/jpeg" => [".jpg", ".jpeg"] + // extensions: "image/jpeg" => [".jfif", ".jpg", ".jpeg", ".pjp", ".pjpeg"] extensionsMu sync.Mutex // Guards stores (but not loads) on extensions. extensions sync.Map // map[string][]string; slice values are append-only. ) @@ -50,23 +50,82 @@ func setMimeTypes(lowerExt, mixExt map[string]string) { } } +// A type is listed here if both Firefox and Chrome included them in their own +// lists. In the case where they contradict they are deconflicted using IANA's +// listed media types https://www.iana.org/assignments/media-types/media-types.xhtml +// +// Chrome's MIME mappings to file extensions are defined at +// https://chromium.googlesource.com/chromium/src.git/+/refs/heads/main/net/base/mime_util.cc +// +// Firefox's MIME types can be found at +// https://github.com/mozilla-firefox/firefox/blob/main/netwerk/mime/nsMimeTypes.h +// and the mappings to file extensions at +// https://github.com/mozilla-firefox/firefox/blob/main/uriloader/exthandler/nsExternalHelperAppService.cpp var builtinTypesLower = map[string]string{ - ".avif": "image/avif", - ".css": "text/css; charset=utf-8", - ".gif": "image/gif", - ".htm": "text/html; charset=utf-8", - ".html": "text/html; charset=utf-8", - ".jpeg": "image/jpeg", - ".jpg": "image/jpeg", - ".js": "text/javascript; charset=utf-8", - ".json": "application/json", - ".mjs": "text/javascript; charset=utf-8", - ".pdf": "application/pdf", - ".png": "image/png", - ".svg": "image/svg+xml", - ".wasm": "application/wasm", - ".webp": "image/webp", - ".xml": "text/xml; charset=utf-8", + ".ai": "application/postscript", + ".apk": "application/vnd.android.package-archive", + ".apng": "image/apng", + ".avif": "image/avif", + ".bin": "application/octet-stream", + ".bmp": "image/bmp", + ".com": "application/octet-stream", + ".css": "text/css; charset=utf-8", + ".csv": "text/csv; charset=utf-8", + ".doc": "application/msword", + ".docx": "application/vnd.openxmlformats-officedocument.wordprocessingml.document", + ".ehtml": "text/html; charset=utf-8", + ".eml": "message/rfc822", + ".eps": "application/postscript", + ".exe": "application/octet-stream", + ".flac": "audio/flac", + ".gif": "image/gif", + ".gz": "application/gzip", + ".htm": "text/html; charset=utf-8", + ".html": "text/html; charset=utf-8", + ".ico": "image/vnd.microsoft.icon", + ".ics": "text/calendar; charset=utf-8", + ".jfif": "image/jpeg", + ".jpeg": "image/jpeg", + ".jpg": "image/jpeg", + ".js": "text/javascript; charset=utf-8", + ".json": "application/json", + ".m4a": "audio/mp4", + ".mjs": "text/javascript; charset=utf-8", + ".mp3": "audio/mpeg", + ".mp4": "video/mp4", + ".oga": "audio/ogg", + ".ogg": "audio/ogg", + ".ogv": "video/ogg", + ".opus": "audio/ogg", + ".pdf": "application/pdf", + ".pjp": "image/jpeg", + ".pjpeg": "image/jpeg", + ".png": "image/png", + ".ppt": "application/vnd.ms-powerpoint", + ".pptx": "application/vnd.openxmlformats-officedocument.presentationml.presentation", + ".ps": "application/postscript", + ".rdf": "application/rdf+xml", + ".rtf": "application/rtf", + ".shtml": "text/html; charset=utf-8", + ".svg": "image/svg+xml", + ".text": "text/plain; charset=utf-8", + ".tif": "image/tiff", + ".tiff": "image/tiff", + ".txt": "text/plain; charset=utf-8", + ".vtt": "text/vtt; charset=utf-8", + ".wasm": "application/wasm", + ".wav": "audio/wav", + ".webm": "audio/webm", + ".webp": "image/webp", + ".xbl": "text/xml; charset=utf-8", + ".xbm": "image/x-xbitmap", + ".xht": "application/xhtml+xml", + ".xhtml": "application/xhtml+xml", + ".xls": "application/vnd.ms-excel", + ".xlsx": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", + ".xml": "text/xml; charset=utf-8", + ".xsl": "text/xml; charset=utf-8", + ".zip": "application/zip", } var once sync.Once // guards initMime diff --git a/src/mime/type_test.go b/src/mime/type_test.go index 6bdf37b6359d20..f4ec8c8754e69f 100644 --- a/src/mime/type_test.go +++ b/src/mime/type_test.go @@ -208,7 +208,51 @@ func TestExtensionsByType2(t *testing.T) { typ string want []string }{ - {typ: "image/jpeg", want: []string{".jpeg", ".jpg"}}, + {typ: "application/postscript", want: []string{".ai", ".eps", ".ps"}}, + {typ: "application/vnd.android.package-archive", want: []string{".apk"}}, + {typ: "image/apng", want: []string{".apng"}}, + {typ: "image/avif", want: []string{".avif"}}, + {typ: "application/octet-stream", want: []string{".bin", ".com", ".exe"}}, + {typ: "image/bmp", want: []string{".bmp"}}, + {typ: "text/css; charset=utf-8", want: []string{".css"}}, + {typ: "text/csv; charset=utf-8", want: []string{".csv"}}, + {typ: "application/msword", want: []string{".doc"}}, + {typ: "application/vnd.openxmlformats-officedocument.wordprocessingml.document", want: []string{".docx"}}, + {typ: "text/html; charset=utf-8", want: []string{".ehtml", ".htm", ".html", ".shtml"}}, + {typ: "message/rfc822", want: []string{".eml"}}, + {typ: "audio/flac", want: []string{".flac"}}, + {typ: "image/gif", want: []string{".gif"}}, + {typ: "application/gzip", want: []string{".gz"}}, + {typ: "image/vnd.microsoft.icon", want: []string{".ico"}}, + {typ: "text/calendar; charset=utf-8", want: []string{".ics"}}, + {typ: "image/jpeg", want: []string{".jfif", ".jpeg", ".jpg", ".pjp", ".pjpeg"}}, + {typ: "text/javascript; charset=utf-8", want: []string{".js", ".mjs"}}, + {typ: "application/json", want: []string{".json"}}, + {typ: "audio/mp4", want: []string{".m4a"}}, + {typ: "audio/mpeg", want: []string{".mp3"}}, + {typ: "video/mp4", want: []string{".mp4"}}, + {typ: "audio/ogg", want: []string{".oga", ".ogg", ".opus"}}, + {typ: "video/ogg", want: []string{".ogv"}}, + {typ: "application/pdf", want: []string{".pdf"}}, + {typ: "image/png", want: []string{".png"}}, + {typ: "application/vnd.ms-powerpoint", want: []string{".ppt"}}, + {typ: "application/vnd.openxmlformats-officedocument.presentationml.presentation", want: []string{".pptx"}}, + {typ: "application/rdf+xml", want: []string{".rdf"}}, + {typ: "application/rtf", want: []string{".rtf"}}, + {typ: "image/svg+xml", want: []string{".svg"}}, + {typ: "text/plain; charset=utf-8", want: []string{".text", ".txt"}}, + {typ: "image/tiff", want: []string{".tif", ".tiff"}}, + {typ: "text/vtt; charset=utf-8", want: []string{".vtt"}}, + {typ: "application/wasm", want: []string{".wasm"}}, + {typ: "audio/wav", want: []string{".wav"}}, + {typ: "audio/webm", want: []string{".webm"}}, + {typ: "image/webp", want: []string{".webp"}}, + {typ: "text/xml; charset=utf-8", want: []string{".xbl", ".xml", ".xsl"}}, + {typ: "image/x-xbitmap", want: []string{".xbm"}}, + {typ: "application/xhtml+xml", want: []string{".xht", ".xhtml"}}, + {typ: "application/vnd.ms-excel", want: []string{".xls"}}, + {typ: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", want: []string{".xlsx"}}, + {typ: "application/zip", want: []string{".zip"}}, } for _, tt := range tests { From 19cc1022ba4e9ddf172c04107fa613e6d50a7eba Mon Sep 17 00:00:00 2001 From: Julien Cretel Date: Mon, 22 Sep 2025 18:05:12 +0000 Subject: [PATCH 023/229] mime: reduce allocs incurred by ParseMediaType MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This change is mostly gardening. It simplifies ParseMediaType and its helper functions and reduces the amount of allocations they incur. Here are some benchmark results: goos: darwin goarch: amd64 pkg: mime cpu: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz │ old │ new │ │ sec/op │ sec/op vs base │ ParseMediaType-8 55.26µ ± 1% 54.54µ ± 1% -1.30% (p=0.000 n=20) ParseMediaTypeBogus-8 3.551µ ± 0% 3.427µ ± 0% -3.48% (p=0.000 n=20) geomean 14.01µ 13.67µ -2.39% │ old │ new │ │ B/op │ B/op vs base │ ParseMediaType-8 38.48Ki ± 0% 37.38Ki ± 0% -2.85% (p=0.000 n=20) ParseMediaTypeBogus-8 2.531Ki ± 0% 2.469Ki ± 0% -2.47% (p=0.000 n=20) geomean 9.869Ki 9.606Ki -2.66% │ old │ new │ │ allocs/op │ allocs/op vs base │ ParseMediaType-8 457.0 ± 0% 425.0 ± 0% -7.00% (p=0.000 n=20) ParseMediaTypeBogus-8 25.00 ± 0% 21.00 ± 0% -16.00% (p=0.000 n=20) geomean 106.9 94.47 -11.62% Change-Id: I51198b40396afa51531794a57c50aa88975eae1d GitHub-Last-Rev: c44e2a2577386d1d776498d29e31821326e20b92 GitHub-Pull-Request: golang/go#75565 Reviewed-on: https://go-review.googlesource.com/c/go/+/705715 Reviewed-by: Emmanuel Odeke Reviewed-by: Carlos Amedee LUCI-TryBot-Result: Go LUCI Reviewed-by: Sean Liao Reviewed-by: Damien Neil Auto-Submit: Emmanuel Odeke --- src/mime/mediatype.go | 67 ++++++++++++++++++++++--------------------- 1 file changed, 35 insertions(+), 32 deletions(-) diff --git a/src/mime/mediatype.go b/src/mime/mediatype.go index 66684a68b23961..c6006b614f319e 100644 --- a/src/mime/mediatype.go +++ b/src/mime/mediatype.go @@ -98,24 +98,32 @@ func FormatMediaType(t string, param map[string]string) string { func checkMediaTypeDisposition(s string) error { typ, rest := consumeToken(s) if typ == "" { - return errors.New("mime: no media type") + return errNoMediaType } if rest == "" { return nil } - if !strings.HasPrefix(rest, "/") { - return errors.New("mime: expected slash after first token") + var ok bool + if rest, ok = strings.CutPrefix(rest, "/"); !ok { + return errNoSlashAfterFirstToken } - subtype, rest := consumeToken(rest[1:]) + subtype, rest := consumeToken(rest) if subtype == "" { - return errors.New("mime: expected token after slash") + return errNoTokenAfterSlash } if rest != "" { - return errors.New("mime: unexpected content after media subtype") + return errUnexpectedContentAfterMediaSubtype } return nil } +var ( + errNoMediaType = errors.New("mime: no media type") + errNoSlashAfterFirstToken = errors.New("mime: expected slash after first token") + errNoTokenAfterSlash = errors.New("mime: expected token after slash") + errUnexpectedContentAfterMediaSubtype = errors.New("mime: unexpected content after media subtype") +) + // ErrInvalidMediaParameter is returned by [ParseMediaType] if // the media type value was found but there was an error parsing // the optional parameters @@ -169,7 +177,6 @@ func ParseMediaType(v string) (mediatype string, params map[string]string, err e if continuation == nil { continuation = make(map[string]map[string]string) } - var ok bool if pmap, ok = continuation[baseName]; !ok { continuation[baseName] = make(map[string]string) pmap = continuation[baseName] @@ -177,7 +184,7 @@ func ParseMediaType(v string) (mediatype string, params map[string]string, err e } if v, exists := pmap[key]; exists && v != value { // Duplicate parameter names are incorrect, but we allow them if they are equal. - return "", nil, errors.New("mime: duplicate parameter name") + return "", nil, errDuplicateParamName } pmap[key] = value v = rest @@ -227,27 +234,28 @@ func ParseMediaType(v string) (mediatype string, params map[string]string, err e return } +var errDuplicateParamName = errors.New("mime: duplicate parameter name") + func decode2231Enc(v string) (string, bool) { - sv := strings.SplitN(v, "'", 3) - if len(sv) != 3 { + charset, v, ok := strings.Cut(v, "'") + if !ok { return "", false } - // TODO: ignoring lang in sv[1] for now. If anybody needs it we'll + // TODO: ignoring the language part for now. If anybody needs it, we'll // need to decide how to expose it in the API. But I'm not sure // anybody uses it in practice. - charset := strings.ToLower(sv[0]) - if len(charset) == 0 { + _, extOtherVals, ok := strings.Cut(v, "'") + if !ok { return "", false } - if charset != "us-ascii" && charset != "utf-8" { - // TODO: unsupported encoding + charset = strings.ToLower(charset) + switch charset { + case "us-ascii", "utf-8": + default: + // Empty or unsupported encoding. return "", false } - encv, err := percentHexUnescape(sv[2]) - if err != nil { - return "", false - } - return encv, true + return percentHexUnescape(extOtherVals) } // consumeToken consumes a token from the beginning of provided @@ -309,11 +317,11 @@ func consumeValue(v string) (value, rest string) { func consumeMediaParam(v string) (param, value, rest string) { rest = strings.TrimLeftFunc(v, unicode.IsSpace) - if !strings.HasPrefix(rest, ";") { + var ok bool + if rest, ok = strings.CutPrefix(rest, ";"); !ok { return "", "", v } - rest = rest[1:] // consume semicolon rest = strings.TrimLeftFunc(rest, unicode.IsSpace) param, rest = consumeToken(rest) param = strings.ToLower(param) @@ -322,10 +330,9 @@ func consumeMediaParam(v string) (param, value, rest string) { } rest = strings.TrimLeftFunc(rest, unicode.IsSpace) - if !strings.HasPrefix(rest, "=") { + if rest, ok = strings.CutPrefix(rest, "="); !ok { return "", "", v } - rest = rest[1:] // consume equals sign rest = strings.TrimLeftFunc(rest, unicode.IsSpace) value, rest2 := consumeValue(rest) if value == "" && rest2 == rest { @@ -335,7 +342,7 @@ func consumeMediaParam(v string) (param, value, rest string) { return param, value, rest } -func percentHexUnescape(s string) (string, error) { +func percentHexUnescape(s string) (string, bool) { // Count %, check that they're well-formed. percents := 0 for i := 0; i < len(s); { @@ -345,16 +352,12 @@ func percentHexUnescape(s string) (string, error) { } percents++ if i+2 >= len(s) || !ishex(s[i+1]) || !ishex(s[i+2]) { - s = s[i:] - if len(s) > 3 { - s = s[0:3] - } - return "", fmt.Errorf("mime: bogus characters after %%: %q", s) + return "", false } i += 3 } if percents == 0 { - return s, nil + return s, true } t := make([]byte, len(s)-2*percents) @@ -371,7 +374,7 @@ func percentHexUnescape(s string) (string, error) { i++ } } - return string(t), nil + return string(t), true } func ishex(c byte) bool { From fcb893fc4b615774f8cdd050e17ad227998e512a Mon Sep 17 00:00:00 2001 From: Youlin Feng Date: Fri, 5 Sep 2025 22:48:48 +0800 Subject: [PATCH 024/229] cmd/compile/internal/ssa: remove redundant "type:" prefix check Remove redundant "type:" prefix check on symbol names in isFixedLoad, also refactor some duplicate code into methods. Change-Id: I8358422596eea8c39d1a30a554bd0aae8b570038 Reviewed-on: https://go-review.googlesource.com/c/go/+/701275 Reviewed-by: Keith Randall Reviewed-by: Keith Randall Auto-Submit: Keith Randall LUCI-TryBot-Result: Go LUCI Reviewed-by: Carlos Amedee --- src/cmd/compile/internal/ssa/rewrite.go | 18 ++++++------------ src/cmd/internal/obj/link.go | 20 +++++++++++++++++++- 2 files changed, 25 insertions(+), 13 deletions(-) diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go index 880c2223ef2229..47f225c7aeb7c0 100644 --- a/src/cmd/compile/internal/ssa/rewrite.go +++ b/src/cmd/compile/internal/ssa/rewrite.go @@ -2059,12 +2059,12 @@ func isFixedLoad(v *Value, sym Sym, off int64) bool { return false } - if strings.HasPrefix(lsym.Name, "type:") { + if ti := lsym.TypeInfo(); ti != nil { // Type symbols do not contain information about their fields, unlike the cases above. // Hand-implement field accesses. // TODO: can this be replaced with reflectdata.writeType and just use the code above? - t := (*lsym.Extra).(*obj.TypeInfo).Type.(*types.Type) + t := ti.Type.(*types.Type) for _, f := range rttype.Type.Fields() { if f.Offset == off && copyCompatibleType(v.Type, f.Type) { @@ -2118,12 +2118,12 @@ func rewriteFixedLoad(v *Value, sym Sym, sb *Value, off int64) *Value { base.Fatalf("fixedLoad data not known for %s:%d", sym, off) } - if strings.HasPrefix(lsym.Name, "type:") { + if ti := lsym.TypeInfo(); ti != nil { // Type symbols do not contain information about their fields, unlike the cases above. // Hand-implement field accesses. // TODO: can this be replaced with reflectdata.writeType and just use the code above? - t := (*lsym.Extra).(*obj.TypeInfo).Type.(*types.Type) + t := ti.Type.(*types.Type) ptrSizedOpConst := OpConst64 if f.Config.PtrSize == 4 { @@ -2613,10 +2613,7 @@ func isDirectType1(v *Value) bool { return isDirectType2(v.Args[0]) case OpAddr: lsym := v.Aux.(*obj.LSym) - if lsym.Extra == nil { - return false - } - if ti, ok := (*lsym.Extra).(*obj.TypeInfo); ok { + if ti := lsym.TypeInfo(); ti != nil { return types.IsDirectIface(ti.Type.(*types.Type)) } } @@ -2649,10 +2646,7 @@ func isDirectIface1(v *Value, depth int) bool { return isDirectIface2(v.Args[0], depth-1) case OpAddr: lsym := v.Aux.(*obj.LSym) - if lsym.Extra == nil { - return false - } - if ii, ok := (*lsym.Extra).(*obj.ItabInfo); ok { + if ii := lsym.ItabInfo(); ii != nil { return types.IsDirectIface(ii.Type.(*types.Type)) } case OpConstNil: diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go index 6513e116872a0a..816fed026f35ad 100644 --- a/src/cmd/internal/obj/link.go +++ b/src/cmd/internal/obj/link.go @@ -464,7 +464,7 @@ type LSym struct { P []byte R []Reloc - Extra *interface{} // *FuncInfo, *VarInfo, *FileInfo, or *TypeInfo, if present + Extra *interface{} // *FuncInfo, *VarInfo, *FileInfo, *TypeInfo, or *ItabInfo, if present Pkg string PkgIdx int32 @@ -604,6 +604,15 @@ func (s *LSym) NewTypeInfo() *TypeInfo { return t } +// TypeInfo returns the *TypeInfo associated with s, or else nil. +func (s *LSym) TypeInfo() *TypeInfo { + if s.Extra == nil { + return nil + } + t, _ := (*s.Extra).(*TypeInfo) + return t +} + // An ItabInfo contains information for a symbol // that contains a runtime.itab. type ItabInfo struct { @@ -620,6 +629,15 @@ func (s *LSym) NewItabInfo() *ItabInfo { return t } +// ItabInfo returns the *ItabInfo associated with s, or else nil. +func (s *LSym) ItabInfo() *ItabInfo { + if s.Extra == nil { + return nil + } + i, _ := (*s.Extra).(*ItabInfo) + return i +} + // WasmImport represents a WebAssembly (WASM) imported function with // parameters and results translated into WASM types based on the Go function // declaration. From 4ff8a457dbe68388a6e2451c78c7ea615f570cda Mon Sep 17 00:00:00 2001 From: Joel Sing Date: Mon, 15 Sep 2025 20:10:05 +1000 Subject: [PATCH 025/229] test/codegen: codify handling of floating point constants on arm64 While here, reorder Float32ConstantStore/Float64ConstantStore for consistency. Change-Id: Ic1b3e9f9474965d15bc94518d78d1a4a7bda93f3 Reviewed-on: https://go-review.googlesource.com/c/go/+/703756 Reviewed-by: Keith Randall Auto-Submit: Keith Randall LUCI-TryBot-Result: Go LUCI Reviewed-by: Carlos Amedee Auto-Submit: Joel Sing Reviewed-by: Keith Randall --- test/codegen/floats.go | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/test/codegen/floats.go b/test/codegen/floats.go index 29969c8dc08eaa..666c983b56ac04 100644 --- a/test/codegen/floats.go +++ b/test/codegen/floats.go @@ -217,14 +217,36 @@ func Float32Max(a, b float32) float32 { // Constant Optimizations // // ------------------------ // +func Float32ConstantZero() float32 { + // arm64:"FMOVS\tZR," + return 0.0 +} + +func Float32ConstantChipFloat() float32 { + // arm64:"FMOVS\t[$]\\(2\\.25\\)," + return 2.25 +} + func Float32Constant() float32 { + // arm64:"FMOVS\t[$]f32\\.42440000\\(SB\\)" // ppc64x/power8:"FMOVS\t[$]f32\\.42440000\\(SB\\)" // ppc64x/power9:"FMOVS\t[$]f32\\.42440000\\(SB\\)" // ppc64x/power10:"XXSPLTIDP\t[$]1111752704," return 49.0 } +func Float64ConstantZero() float64 { + // arm64:"FMOVD\tZR," + return 0.0 +} + +func Float64ConstantChipFloat() float64 { + // arm64:"FMOVD\t[$]\\(2\\.25\\)," + return 2.25 +} + func Float64Constant() float64 { + // arm64:"FMOVD\t[$]f64\\.4048800000000000\\(SB\\)" // ppc64x/power8:"FMOVD\t[$]f64\\.4048800000000000\\(SB\\)" // ppc64x/power9:"FMOVD\t[$]f64\\.4048800000000000\\(SB\\)" // ppc64x/power10:"XXSPLTIDP\t[$]1111752704," @@ -244,11 +266,12 @@ func Float64DenormalFloat32Constant() float64 { return 0x1p-127 } -func Float64ConstantStore(p *float64) { - // amd64: "MOVQ\t[$]4617801906721357038" +func Float32ConstantStore(p *float32) { + // amd64:"MOVL\t[$]1085133554" *p = 5.432 } -func Float32ConstantStore(p *float32) { - // amd64: "MOVL\t[$]1085133554" + +func Float64ConstantStore(p *float64) { + // amd64:"MOVQ\t[$]4617801906721357038" *p = 5.432 } From c9257151e5600af10cdd6c6db907ed83811a54a4 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Wed, 24 Sep 2025 08:58:30 +0200 Subject: [PATCH 026/229] runtime: unify ppc64/ppc64le library entry point Cq-Include-Trybots: luci.golang.try:gotip-linux-ppc64le_power10 Change-Id: Ifd7861488b1b47a5d30163552b51838f2bef7248 Reviewed-on: https://go-review.googlesource.com/c/go/+/706395 Reviewed-by: Carlos Amedee Reviewed-by: Keith Randall Reviewed-by: Keith Randall Auto-Submit: Keith Randall LUCI-TryBot-Result: Go LUCI --- src/runtime/asm_ppc64x.s | 57 ++++++++++++ src/runtime/rt0_aix_ppc64.s | 151 +------------------------------- src/runtime/rt0_linux_ppc64le.s | 49 +---------- 3 files changed, 60 insertions(+), 197 deletions(-) diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s index fc70fa82046056..3fbf11b5e9a2ad 100644 --- a/src/runtime/asm_ppc64x.s +++ b/src/runtime/asm_ppc64x.s @@ -9,6 +9,63 @@ #include "funcdata.h" #include "textflag.h" #include "asm_ppc64x.h" +#include "cgo/abi_ppc64x.h" + + +TEXT _rt0_ppc64x_lib(SB),NOSPLIT|NOFRAME,$0 + // This is called with ELFv2 calling conventions. Convert to Go. + // Allocate argument storage for call to newosproc0. + STACK_AND_SAVE_HOST_TO_GO_ABI(16) + + MOVD R3, _rt0_ppc64x_lib_argc<>(SB) + MOVD R4, _rt0_ppc64x_lib_argv<>(SB) + + // Synchronous initialization. + MOVD $runtime·libpreinit(SB), R12 + MOVD R12, CTR + BL (CTR) + + // Create a new thread to do the runtime initialization and return. + MOVD _cgo_sys_thread_create(SB), R12 + CMP $0, R12 + BEQ nocgo + MOVD $_rt0_ppc64x_lib_go(SB), R3 + MOVD $0, R4 + MOVD R12, CTR + BL (CTR) + BR done + +nocgo: + MOVD $0x800000, R12 // stacksize = 8192KB + MOVD R12, 8+FIXED_FRAME(R1) + MOVD $_rt0_ppc64x_lib_go(SB), R12 + MOVD R12, 16+FIXED_FRAME(R1) + MOVD $runtime·newosproc0(SB),R12 + MOVD R12, CTR + BL (CTR) + +done: + // Restore and return to ELFv2 caller. + UNSTACK_AND_RESTORE_GO_TO_HOST_ABI(16) + RET + +#ifdef GO_PPC64X_HAS_FUNCDESC +DEFINE_PPC64X_FUNCDESC(_rt0_ppc64x_lib_go, __rt0_ppc64x_lib_go) +TEXT __rt0_ppc64x_lib_go(SB),NOSPLIT,$0 +#else +TEXT _rt0_ppc64x_lib_go(SB),NOSPLIT,$0 +#endif + MOVD _rt0_ppc64x_lib_argc<>(SB), R3 + MOVD _rt0_ppc64x_lib_argv<>(SB), R4 + MOVD $runtime·rt0_go(SB), R12 + MOVD R12, CTR + BR (CTR) + +DATA _rt0_ppc64x_lib_argc<>(SB)/8, $0 +GLOBL _rt0_ppc64x_lib_argc<>(SB),NOPTR, $8 +DATA _rt0_ppc64x_lib_argv<>(SB)/8, $0 +GLOBL _rt0_ppc64x_lib_argv<>(SB),NOPTR, $8 + #ifdef GOOS_aix #define cgoCalleeStackSize 48 diff --git a/src/runtime/rt0_aix_ppc64.s b/src/runtime/rt0_aix_ppc64.s index 74c57bb1dc9136..32f8c72156c9ee 100644 --- a/src/runtime/rt0_aix_ppc64.s +++ b/src/runtime/rt0_aix_ppc64.s @@ -41,152 +41,5 @@ TEXT _main(SB),NOSPLIT,$-8 MOVD R12, CTR BR (CTR) -// Paramater save space required to cross-call into _cgo_sys_thread_create -#define PARAM_SPACE 16 - -TEXT _rt0_ppc64_aix_lib(SB),NOSPLIT,$-8 - // Start with standard C stack frame layout and linkage. - MOVD LR, R0 - MOVD R0, 16(R1) // Save LR in caller's frame. - MOVW CR, R0 // Save CR in caller's frame - MOVD R0, 8(R1) - - MOVDU R1, -344-PARAM_SPACE(R1) // Allocate frame. - - // Preserve callee-save registers. - MOVD R14, 48+PARAM_SPACE(R1) - MOVD R15, 56+PARAM_SPACE(R1) - MOVD R16, 64+PARAM_SPACE(R1) - MOVD R17, 72+PARAM_SPACE(R1) - MOVD R18, 80+PARAM_SPACE(R1) - MOVD R19, 88+PARAM_SPACE(R1) - MOVD R20, 96+PARAM_SPACE(R1) - MOVD R21,104+PARAM_SPACE(R1) - MOVD R22, 112+PARAM_SPACE(R1) - MOVD R23, 120+PARAM_SPACE(R1) - MOVD R24, 128+PARAM_SPACE(R1) - MOVD R25, 136+PARAM_SPACE(R1) - MOVD R26, 144+PARAM_SPACE(R1) - MOVD R27, 152+PARAM_SPACE(R1) - MOVD R28, 160+PARAM_SPACE(R1) - MOVD R29, 168+PARAM_SPACE(R1) - MOVD g, 176+PARAM_SPACE(R1) // R30 - MOVD R31, 184+PARAM_SPACE(R1) - FMOVD F14, 192+PARAM_SPACE(R1) - FMOVD F15, 200+PARAM_SPACE(R1) - FMOVD F16, 208+PARAM_SPACE(R1) - FMOVD F17, 216+PARAM_SPACE(R1) - FMOVD F18, 224+PARAM_SPACE(R1) - FMOVD F19, 232+PARAM_SPACE(R1) - FMOVD F20, 240+PARAM_SPACE(R1) - FMOVD F21, 248+PARAM_SPACE(R1) - FMOVD F22, 256+PARAM_SPACE(R1) - FMOVD F23, 264+PARAM_SPACE(R1) - FMOVD F24, 272+PARAM_SPACE(R1) - FMOVD F25, 280+PARAM_SPACE(R1) - FMOVD F26, 288+PARAM_SPACE(R1) - FMOVD F27, 296+PARAM_SPACE(R1) - FMOVD F28, 304+PARAM_SPACE(R1) - FMOVD F29, 312+PARAM_SPACE(R1) - FMOVD F30, 320+PARAM_SPACE(R1) - FMOVD F31, 328+PARAM_SPACE(R1) - - // Synchronous initialization. - MOVD $runtime·reginit(SB), R12 - MOVD R12, CTR - BL (CTR) - - MOVBZ runtime·isarchive(SB), R3 // Check buildmode = c-archive - CMP $0, R3 - BEQ done - - MOVD R14, _rt0_ppc64_aix_lib_argc<>(SB) - MOVD R15, _rt0_ppc64_aix_lib_argv<>(SB) - - MOVD $runtime·libpreinit(SB), R12 - MOVD R12, CTR - BL (CTR) - - // Create a new thread to do the runtime initialization and return. - MOVD _cgo_sys_thread_create(SB), R12 - CMP $0, R12 - BEQ nocgo - MOVD $_rt0_ppc64_aix_lib_go(SB), R3 - MOVD $0, R4 - MOVD R2, 40(R1) - MOVD 8(R12), R2 - MOVD (R12), R12 - MOVD R12, CTR - BL (CTR) - MOVD 40(R1), R2 - BR done - -nocgo: - MOVD $0x800000, R12 // stacksize = 8192KB - MOVD R12, 8(R1) - MOVD $_rt0_ppc64_aix_lib_go(SB), R12 - MOVD R12, 16(R1) - MOVD $runtime·newosproc0(SB),R12 - MOVD R12, CTR - BL (CTR) - -done: - // Restore saved registers. - MOVD 48+PARAM_SPACE(R1), R14 - MOVD 56+PARAM_SPACE(R1), R15 - MOVD 64+PARAM_SPACE(R1), R16 - MOVD 72+PARAM_SPACE(R1), R17 - MOVD 80+PARAM_SPACE(R1), R18 - MOVD 88+PARAM_SPACE(R1), R19 - MOVD 96+PARAM_SPACE(R1), R20 - MOVD 104+PARAM_SPACE(R1), R21 - MOVD 112+PARAM_SPACE(R1), R22 - MOVD 120+PARAM_SPACE(R1), R23 - MOVD 128+PARAM_SPACE(R1), R24 - MOVD 136+PARAM_SPACE(R1), R25 - MOVD 144+PARAM_SPACE(R1), R26 - MOVD 152+PARAM_SPACE(R1), R27 - MOVD 160+PARAM_SPACE(R1), R28 - MOVD 168+PARAM_SPACE(R1), R29 - MOVD 176+PARAM_SPACE(R1), g // R30 - MOVD 184+PARAM_SPACE(R1), R31 - FMOVD 196+PARAM_SPACE(R1), F14 - FMOVD 200+PARAM_SPACE(R1), F15 - FMOVD 208+PARAM_SPACE(R1), F16 - FMOVD 216+PARAM_SPACE(R1), F17 - FMOVD 224+PARAM_SPACE(R1), F18 - FMOVD 232+PARAM_SPACE(R1), F19 - FMOVD 240+PARAM_SPACE(R1), F20 - FMOVD 248+PARAM_SPACE(R1), F21 - FMOVD 256+PARAM_SPACE(R1), F22 - FMOVD 264+PARAM_SPACE(R1), F23 - FMOVD 272+PARAM_SPACE(R1), F24 - FMOVD 280+PARAM_SPACE(R1), F25 - FMOVD 288+PARAM_SPACE(R1), F26 - FMOVD 296+PARAM_SPACE(R1), F27 - FMOVD 304+PARAM_SPACE(R1), F28 - FMOVD 312+PARAM_SPACE(R1), F29 - FMOVD 320+PARAM_SPACE(R1), F30 - FMOVD 328+PARAM_SPACE(R1), F31 - - ADD $344+PARAM_SPACE, R1 - - MOVD 8(R1), R0 - MOVFL R0, $0xff - MOVD 16(R1), R0 - MOVD R0, LR - RET - -DEFINE_PPC64X_FUNCDESC(_rt0_ppc64_aix_lib_go, __rt0_ppc64_aix_lib_go) - -TEXT __rt0_ppc64_aix_lib_go(SB),NOSPLIT,$0 - MOVD _rt0_ppc64_aix_lib_argc<>(SB), R3 - MOVD _rt0_ppc64_aix_lib_argv<>(SB), R4 - MOVD $runtime·rt0_go(SB), R12 - MOVD R12, CTR - BR (CTR) - -DATA _rt0_ppc64_aix_lib_argc<>(SB)/8, $0 -GLOBL _rt0_ppc64_aix_lib_argc<>(SB),NOPTR, $8 -DATA _rt0_ppc64_aix_lib_argv<>(SB)/8, $0 -GLOBL _rt0_ppc64_aix_lib_argv<>(SB),NOPTR, $8 +TEXT _rt0_ppc64_aix_lib(SB),NOSPLIT,$0 + JMP _rt0_ppc64x_lib(SB) diff --git a/src/runtime/rt0_linux_ppc64le.s b/src/runtime/rt0_linux_ppc64le.s index 4b7d8e1b940a1e..3a6e8863b2da1d 100644 --- a/src/runtime/rt0_linux_ppc64le.s +++ b/src/runtime/rt0_linux_ppc64le.s @@ -5,60 +5,13 @@ #include "go_asm.h" #include "textflag.h" #include "asm_ppc64x.h" -#include "cgo/abi_ppc64x.h" TEXT _rt0_ppc64le_linux(SB),NOSPLIT,$0 XOR R0, R0 // Make sure R0 is zero before _main BR _main<>(SB) TEXT _rt0_ppc64le_linux_lib(SB),NOSPLIT|NOFRAME,$0 - // This is called with ELFv2 calling conventions. Convert to Go. - // Allocate argument storage for call to newosproc0. - STACK_AND_SAVE_HOST_TO_GO_ABI(16) - - MOVD R3, _rt0_ppc64le_linux_lib_argc<>(SB) - MOVD R4, _rt0_ppc64le_linux_lib_argv<>(SB) - - // Synchronous initialization. - MOVD $runtime·libpreinit(SB), R12 - MOVD R12, CTR - BL (CTR) - - // Create a new thread to do the runtime initialization and return. - MOVD _cgo_sys_thread_create(SB), R12 - CMP $0, R12 - BEQ nocgo - MOVD $_rt0_ppc64le_linux_lib_go(SB), R3 - MOVD $0, R4 - MOVD R12, CTR - BL (CTR) - BR done - -nocgo: - MOVD $0x800000, R12 // stacksize = 8192KB - MOVD R12, 8+FIXED_FRAME(R1) - MOVD $_rt0_ppc64le_linux_lib_go(SB), R12 - MOVD R12, 16+FIXED_FRAME(R1) - MOVD $runtime·newosproc0(SB),R12 - MOVD R12, CTR - BL (CTR) - -done: - // Restore and return to ELFv2 caller. - UNSTACK_AND_RESTORE_GO_TO_HOST_ABI(16) - RET - -TEXT _rt0_ppc64le_linux_lib_go(SB),NOSPLIT,$0 - MOVD _rt0_ppc64le_linux_lib_argc<>(SB), R3 - MOVD _rt0_ppc64le_linux_lib_argv<>(SB), R4 - MOVD $runtime·rt0_go(SB), R12 - MOVD R12, CTR - BR (CTR) - -DATA _rt0_ppc64le_linux_lib_argc<>(SB)/8, $0 -GLOBL _rt0_ppc64le_linux_lib_argc<>(SB),NOPTR, $8 -DATA _rt0_ppc64le_linux_lib_argv<>(SB)/8, $0 -GLOBL _rt0_ppc64le_linux_lib_argv<>(SB),NOPTR, $8 + JMP _rt0_ppc64x_lib(SB) TEXT _main<>(SB),NOSPLIT,$-8 // In a statically linked binary, the stack contains argc, From eb1c7f6e69b0e62067ff22a0656cedff792c8438 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Wed, 24 Sep 2025 10:34:25 +0200 Subject: [PATCH 027/229] runtime: move loong64 library entry point to os-agnostic file The library entry point for loong64 is agnostic to the OS, so move it to asm_loong64.s. This is similar to what we do for other architectures. Cq-Include-Trybots: luci.golang.try:gotip-linux-loong64 Change-Id: I6915eb76d3ea72a779e05e78d85f24793169c61f Reviewed-on: https://go-review.googlesource.com/c/go/+/706416 Reviewed-by: abner chenc Reviewed-by: Cherry Mui Reviewed-by: Keith Randall LUCI-TryBot-Result: Go LUCI --- src/runtime/asm_loong64.s | 51 +++++++++++++++++++++++++++++++++ src/runtime/rt0_linux_loong64.s | 50 ++------------------------------ 2 files changed, 53 insertions(+), 48 deletions(-) diff --git a/src/runtime/asm_loong64.s b/src/runtime/asm_loong64.s index ee7f825e1f6681..586bf89a5d3729 100644 --- a/src/runtime/asm_loong64.s +++ b/src/runtime/asm_loong64.s @@ -6,6 +6,57 @@ #include "go_tls.h" #include "funcdata.h" #include "textflag.h" +#include "cgo/abi_loong64.h" + +// When building with -buildmode=c-shared, this symbol is called when the shared +// library is loaded. +TEXT _rt0_loong64_lib(SB),NOSPLIT,$168 + // Preserve callee-save registers. + SAVE_R22_TO_R31(3*8) + SAVE_F24_TO_F31(13*8) + + // Initialize g as nil in case of using g later e.g. sigaction in cgo_sigaction.go + MOVV R0, g + + MOVV R4, _rt0_loong64_lib_argc<>(SB) + MOVV R5, _rt0_loong64_lib_argv<>(SB) + + // Synchronous initialization. + MOVV $runtime·libpreinit(SB), R19 + JAL (R19) + + // Create a new thread to do the runtime initialization and return. + MOVV _cgo_sys_thread_create(SB), R19 + BEQ R19, nocgo + MOVV $_rt0_loong64_lib_go(SB), R4 + MOVV $0, R5 + JAL (R19) + JMP restore + +nocgo: + MOVV $0x800000, R4 // stacksize = 8192KB + MOVV $_rt0_loong64_lib_go(SB), R5 + MOVV R4, 8(R3) + MOVV R5, 16(R3) + MOVV $runtime·newosproc0(SB), R19 + JAL (R19) + +restore: + // Restore callee-save registers. + RESTORE_R22_TO_R31(3*8) + RESTORE_F24_TO_F31(13*8) + RET + +TEXT _rt0_loong64_lib_go(SB),NOSPLIT,$0 + MOVV _rt0_loong64_lib_argc<>(SB), R4 + MOVV _rt0_loong64_lib_argv<>(SB), R5 + MOVV $runtime·rt0_go(SB),R19 + JMP (R19) + +DATA _rt0_loong64_lib_argc<>(SB)/8, $0 +GLOBL _rt0_loong64_lib_argc<>(SB),NOPTR, $8 +DATA _rt0_loong64_lib_argv<>(SB)/8, $0 +GLOBL _rt0_loong64_lib_argv<>(SB),NOPTR, $8 #define REGCTXT R29 diff --git a/src/runtime/rt0_linux_loong64.s b/src/runtime/rt0_linux_loong64.s index b52f7d530a6a98..d8da4461a2f56d 100644 --- a/src/runtime/rt0_linux_loong64.s +++ b/src/runtime/rt0_linux_loong64.s @@ -3,7 +3,6 @@ // license that can be found in the LICENSE file. #include "textflag.h" -#include "cgo/abi_loong64.h" TEXT _rt0_loong64_linux(SB),NOSPLIT|NOFRAME,$0 // In a statically linked binary, the stack contains argc, @@ -16,53 +15,8 @@ TEXT _rt0_loong64_linux(SB),NOSPLIT|NOFRAME,$0 // When building with -buildmode=c-shared, this symbol is called when the shared // library is loaded. -TEXT _rt0_loong64_linux_lib(SB),NOSPLIT,$168 - // Preserve callee-save registers. - SAVE_R22_TO_R31(3*8) - SAVE_F24_TO_F31(13*8) - - // Initialize g as nil in case of using g later e.g. sigaction in cgo_sigaction.go - MOVV R0, g - - MOVV R4, _rt0_loong64_linux_lib_argc<>(SB) - MOVV R5, _rt0_loong64_linux_lib_argv<>(SB) - - // Synchronous initialization. - MOVV $runtime·libpreinit(SB), R19 - JAL (R19) - - // Create a new thread to do the runtime initialization and return. - MOVV _cgo_sys_thread_create(SB), R19 - BEQ R19, nocgo - MOVV $_rt0_loong64_linux_lib_go(SB), R4 - MOVV $0, R5 - JAL (R19) - JMP restore - -nocgo: - MOVV $0x800000, R4 // stacksize = 8192KB - MOVV $_rt0_loong64_linux_lib_go(SB), R5 - MOVV R4, 8(R3) - MOVV R5, 16(R3) - MOVV $runtime·newosproc0(SB), R19 - JAL (R19) - -restore: - // Restore callee-save registers. - RESTORE_R22_TO_R31(3*8) - RESTORE_F24_TO_F31(13*8) - RET - -TEXT _rt0_loong64_linux_lib_go(SB),NOSPLIT,$0 - MOVV _rt0_loong64_linux_lib_argc<>(SB), R4 - MOVV _rt0_loong64_linux_lib_argv<>(SB), R5 - MOVV $runtime·rt0_go(SB),R19 - JMP (R19) - -DATA _rt0_loong64_linux_lib_argc<>(SB)/8, $0 -GLOBL _rt0_loong64_linux_lib_argc<>(SB),NOPTR, $8 -DATA _rt0_loong64_linux_lib_argv<>(SB)/8, $0 -GLOBL _rt0_loong64_linux_lib_argv<>(SB),NOPTR, $8 +TEXT _rt0_loong64_linux_lib(SB),NOSPLIT,$0 + JMP _rt0_loong64_lib(SB) TEXT main(SB),NOSPLIT|NOFRAME,$0 // in external linking, glibc jumps to main with argc in R4 From be0fed8a5fc4e34f2c6caf503830bcdf904ded54 Mon Sep 17 00:00:00 2001 From: Alan Donovan Date: Tue, 30 Sep 2025 15:11:58 -0400 Subject: [PATCH 028/229] cmd/go/testdata/script/test_fuzz_fuzztime.txt: disable This test features a 5s timeout, which is far too close to the natural variance in scheduling on an overloaded CI builder machine to make a reliable test. Skipping. Updates #72104 Change-Id: I52133a2d101808c923e316e0c7fdce9edbb31b10 Reviewed-on: https://go-review.googlesource.com/c/go/+/708075 Auto-Submit: Alan Donovan LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Matloob Reviewed-by: Michael Matloob --- src/cmd/go/testdata/script/test_fuzz_fuzztime.txt | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt b/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt index 027c434a322ec1..3cc23985a3934a 100644 --- a/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt +++ b/src/cmd/go/testdata/script/test_fuzz_fuzztime.txt @@ -1,3 +1,5 @@ +skip # a 5s timeout is never going to be reliable (go.dev/issue/72140) + [!fuzz] skip [short] skip env GOCACHE=$WORK/cache From 3f451f2c54c87db8b8f30e4d5224933f7895f453 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20G=2E=20MARAND?= Date: Wed, 1 Oct 2025 12:46:16 +0000 Subject: [PATCH 029/229] testing/synctest: fix inverted test failure message in TestContextAfterFunc Fixes #75685 Change-Id: I5592becfde6aaca3d7f0e2f09bc7a9785228523e GitHub-Last-Rev: 0ff7bd31ecfc23222dae70194621397330f3c2da GitHub-Pull-Request: golang/go#75687 Reviewed-on: https://go-review.googlesource.com/c/go/+/708275 Reviewed-by: Alan Donovan Auto-Submit: Alan Donovan LUCI-TryBot-Result: Go LUCI Auto-Submit: Damien Neil Auto-Submit: Sean Liao Reviewed-by: Damien Neil Reviewed-by: Sean Liao --- src/testing/synctest/example_test.go | 2 +- src/testing/synctest/synctest.go | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/src/testing/synctest/example_test.go b/src/testing/synctest/example_test.go index 843377ea88ef71..a86d87fcecdca1 100644 --- a/src/testing/synctest/example_test.go +++ b/src/testing/synctest/example_test.go @@ -66,7 +66,7 @@ func TestContextAfterFunc(t *testing.T) { cancel() synctest.Wait() if !afterFuncCalled { - t.Fatalf("before context is canceled: AfterFunc not called") + t.Fatalf("after context is canceled: AfterFunc not called") } }) } diff --git a/src/testing/synctest/synctest.go b/src/testing/synctest/synctest.go index 707383f9c75499..9f499515b8881a 100644 --- a/src/testing/synctest/synctest.go +++ b/src/testing/synctest/synctest.go @@ -147,7 +147,7 @@ // cancel() // synctest.Wait() // if !afterFuncCalled { -// t.Fatalf("before context is canceled: AfterFunc not called") +// t.Fatalf("after context is canceled: AfterFunc not called") // } // }) // } From 8ad27fb656ab162546137b512c61f6a26a90a6c5 Mon Sep 17 00:00:00 2001 From: Alan Donovan Date: Wed, 1 Oct 2025 15:07:57 -0400 Subject: [PATCH 030/229] doc/go_spec.html: update date (addressing comment from review of CL 704737) Change-Id: I483dea046f664035e79c51729203c9a9ff0cbc59 Reviewed-on: https://go-review.googlesource.com/c/go/+/708299 Auto-Submit: Alan Donovan Reviewed-by: Robert Griesemer LUCI-TryBot-Result: Go LUCI --- doc/go_spec.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/doc/go_spec.html b/doc/go_spec.html index b67eaf9999ab1e..92afe1cee0baef 100644 --- a/doc/go_spec.html +++ b/doc/go_spec.html @@ -1,6 +1,6 @@ From 633dd1d475e7346b43d87abc987a8c7f256e827d Mon Sep 17 00:00:00 2001 From: Joe Tsai Date: Mon, 15 Sep 2025 12:56:11 -0700 Subject: [PATCH 031/229] encoding/json: fix Decoder.InputOffset regression in goexperiment.jsonv2 The Decoder.InputOffset method was always ambiguous about the exact offset returned since anything between the end of the previous token to the start of the next token could be a valid result. Empirically, it seems that the behavior was to report the end of the previous token unless Decoder.More is called, in which case it reports the start of the next token. This is an odd semantic since a relatively side-effect free method like More is not quite so side-effect free. However, our goal is to preserve historical v1 semantic when possible regardless of whether it made sense. Note that jsontext.Decoder.InputOffset consistently always reports the end of the previous token. Users can explicitly choose the exact position they want by inspecting the UnreadBuffer. Fixes #75468 Change-Id: I1e946e83c9d29dfc09f2913ff8d6b2b80632f292 Reviewed-on: https://go-review.googlesource.com/c/go/+/703856 Reviewed-by: Damien Neil LUCI-TryBot-Result: Go LUCI Reviewed-by: Junyang Shao --- src/encoding/json/stream_test.go | 64 +++++++++++++++++++++++++++++ src/encoding/json/v2_stream.go | 22 +++++++++- src/encoding/json/v2_stream_test.go | 64 +++++++++++++++++++++++++++++ 3 files changed, 149 insertions(+), 1 deletion(-) diff --git a/src/encoding/json/stream_test.go b/src/encoding/json/stream_test.go index 9e5d48d39d2fcf..0e937cfaa13c78 100644 --- a/src/encoding/json/stream_test.go +++ b/src/encoding/json/stream_test.go @@ -557,3 +557,67 @@ func TestTokenTruncation(t *testing.T) { } } } + +func TestDecoderInputOffset(t *testing.T) { + const input = ` [ + [ ] , [ "one" ] , [ "one" , "two" ] , + { } , { "alpha" : "bravo" } , { "alpha" : "bravo" , "fizz" : "buzz" } + ] ` + wantOffsets := []int64{ + 0, 1, 2, 5, 6, 7, 8, 9, 12, 13, 18, 19, 20, 21, 24, 25, 30, 31, + 38, 39, 40, 41, 46, 47, 48, 49, 52, 53, 60, 61, 70, 71, 72, 73, + 76, 77, 84, 85, 94, 95, 103, 104, 112, 113, 114, 116, 117, 117, + 117, 117, + } + wantMores := []bool{ + true, true, false, true, true, false, true, true, true, false, + true, false, true, true, true, false, true, true, true, true, + true, false, false, false, false, + } + + d := NewDecoder(strings.NewReader(input)) + checkOffset := func() { + t.Helper() + got := d.InputOffset() + if len(wantOffsets) == 0 { + t.Fatalf("InputOffset = %d, want nil", got) + } + want := wantOffsets[0] + if got != want { + t.Fatalf("InputOffset = %d, want %d", got, want) + } + wantOffsets = wantOffsets[1:] + } + checkMore := func() { + t.Helper() + got := d.More() + if len(wantMores) == 0 { + t.Fatalf("More = %v, want nil", got) + } + want := wantMores[0] + if got != want { + t.Fatalf("More = %v, want %v", got, want) + } + wantMores = wantMores[1:] + } + checkOffset() + checkMore() + checkOffset() + for { + if _, err := d.Token(); err == io.EOF { + break + } else if err != nil { + t.Fatalf("Token error: %v", err) + } + checkOffset() + checkMore() + checkOffset() + } + checkOffset() + checkMore() + checkOffset() + + if len(wantOffsets)+len(wantMores) > 0 { + t.Fatal("unconsumed testdata") + } +} diff --git a/src/encoding/json/v2_stream.go b/src/encoding/json/v2_stream.go index 28e72c0a529e15..dcee553ee13336 100644 --- a/src/encoding/json/v2_stream.go +++ b/src/encoding/json/v2_stream.go @@ -20,6 +20,10 @@ type Decoder struct { dec *jsontext.Decoder opts jsonv2.Options err error + + // hadPeeked reports whether [Decoder.More] was called. + // It is reset by [Decoder.Decode] and [Decoder.Token]. + hadPeeked bool } // NewDecoder returns a new decoder that reads from r. @@ -76,6 +80,7 @@ func (dec *Decoder) Decode(v any) error { } return dec.err } + dec.hadPeeked = false return jsonv2.Unmarshal(b, v, dec.opts) } @@ -206,6 +211,7 @@ func (dec *Decoder) Token() (Token, error) { } return nil, transformSyntacticError(err) } + dec.hadPeeked = false switch k := tok.Kind(); k { case 'n': return nil, nil @@ -230,6 +236,7 @@ func (dec *Decoder) Token() (Token, error) { // More reports whether there is another element in the // current array or object being parsed. func (dec *Decoder) More() bool { + dec.hadPeeked = true k := dec.dec.PeekKind() return k > 0 && k != ']' && k != '}' } @@ -238,5 +245,18 @@ func (dec *Decoder) More() bool { // The offset gives the location of the end of the most recently returned token // and the beginning of the next token. func (dec *Decoder) InputOffset() int64 { - return dec.dec.InputOffset() + offset := dec.dec.InputOffset() + if dec.hadPeeked { + // Historically, InputOffset reported the location of + // the end of the most recently returned token + // unless [Decoder.More] is called, in which case, it reported + // the beginning of the next token. + unreadBuffer := dec.dec.UnreadBuffer() + trailingTokens := bytes.TrimLeft(unreadBuffer, " \n\r\t") + if len(trailingTokens) > 0 { + leadingWhitespace := len(unreadBuffer) - len(trailingTokens) + offset += int64(leadingWhitespace) + } + } + return offset } diff --git a/src/encoding/json/v2_stream_test.go b/src/encoding/json/v2_stream_test.go index b8951f82054e96..0885631fb5937f 100644 --- a/src/encoding/json/v2_stream_test.go +++ b/src/encoding/json/v2_stream_test.go @@ -537,3 +537,67 @@ func TestTokenTruncation(t *testing.T) { } } } + +func TestDecoderInputOffset(t *testing.T) { + const input = ` [ + [ ] , [ "one" ] , [ "one" , "two" ] , + { } , { "alpha" : "bravo" } , { "alpha" : "bravo" , "fizz" : "buzz" } + ] ` + wantOffsets := []int64{ + 0, 1, 2, 5, 6, 7, 8, 9, 12, 13, 18, 19, 20, 21, 24, 25, 30, 31, + 38, 39, 40, 41, 46, 47, 48, 49, 52, 53, 60, 61, 70, 71, 72, 73, + 76, 77, 84, 85, 94, 95, 103, 104, 112, 113, 114, 116, 117, 117, + 117, 117, + } + wantMores := []bool{ + true, true, false, true, true, false, true, true, true, false, + true, false, true, true, true, false, true, true, true, true, + true, false, false, false, false, + } + + d := NewDecoder(strings.NewReader(input)) + checkOffset := func() { + t.Helper() + got := d.InputOffset() + if len(wantOffsets) == 0 { + t.Fatalf("InputOffset = %d, want nil", got) + } + want := wantOffsets[0] + if got != want { + t.Fatalf("InputOffset = %d, want %d", got, want) + } + wantOffsets = wantOffsets[1:] + } + checkMore := func() { + t.Helper() + got := d.More() + if len(wantMores) == 0 { + t.Fatalf("More = %v, want nil", got) + } + want := wantMores[0] + if got != want { + t.Fatalf("More = %v, want %v", got, want) + } + wantMores = wantMores[1:] + } + checkOffset() + checkMore() + checkOffset() + for { + if _, err := d.Token(); err == io.EOF { + break + } else if err != nil { + t.Fatalf("Token error: %v", err) + } + checkOffset() + checkMore() + checkOffset() + } + checkOffset() + checkMore() + checkOffset() + + if len(wantOffsets)+len(wantMores) > 0 { + t.Fatal("unconsumed testdata") + } +} From 5799c139a77e9c3a5750c90ebda538131f4517d6 Mon Sep 17 00:00:00 2001 From: Daniel McCarney Date: Mon, 29 Sep 2025 14:31:38 -0400 Subject: [PATCH 032/229] crypto/tls: rm marshalEncryptedClientHelloConfigList dead code This package internal function has no call sites. Change-Id: I262058199fd2f387ef3b5e21099421720cc5413e Reviewed-on: https://go-review.googlesource.com/c/go/+/707815 TryBot-Bypass: Daniel McCarney Auto-Submit: Roland Shoemaker Auto-Submit: Daniel McCarney Reviewed-by: Carlos Amedee Reviewed-by: Roland Shoemaker --- src/crypto/tls/ech.go | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/src/crypto/tls/ech.go b/src/crypto/tls/ech.go index 76727a890896a0..d3472d8dc4aafb 100644 --- a/src/crypto/tls/ech.go +++ b/src/crypto/tls/ech.go @@ -568,16 +568,6 @@ func parseECHExt(ext []byte) (echType echExtType, cs echCipher, configID uint8, return echType, cs, configID, bytes.Clone(encap), bytes.Clone(payload), nil } -func marshalEncryptedClientHelloConfigList(configs []EncryptedClientHelloKey) ([]byte, error) { - builder := cryptobyte.NewBuilder(nil) - builder.AddUint16LengthPrefixed(func(builder *cryptobyte.Builder) { - for _, c := range configs { - builder.AddBytes(c.Config) - } - }) - return builder.Bytes() -} - func (c *Conn) processECHClientHello(outer *clientHelloMsg, echKeys []EncryptedClientHelloKey) (*clientHelloMsg, *echServerContext, error) { echType, echCiphersuite, configID, encap, payload, err := parseECHExt(outer.encryptedClientHello) if err != nil { From 84db201ae18c889acdefe20c8a903b188328f16d Mon Sep 17 00:00:00 2001 From: Mateusz Poliwczak Date: Fri, 26 Sep 2025 20:47:45 +0200 Subject: [PATCH 033/229] cmd/compile: propagate len([]T{}) to make builtin to allow stack allocation Updates #75620 Change-Id: I6a6a6964af4512e30eb4806e1dc7b0fd0835744f Reviewed-on: https://go-review.googlesource.com/c/go/+/707255 Reviewed-by: Keith Randall Reviewed-by: Keith Randall LUCI-TryBot-Result: Go LUCI Auto-Submit: Keith Randall Reviewed-by: Carlos Amedee --- src/cmd/compile/internal/escape/escape.go | 13 ++++++++++++- test/escape_make_non_const.go | 15 +++++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/src/cmd/compile/internal/escape/escape.go b/src/cmd/compile/internal/escape/escape.go index 6b34830b3dd5e6..59250edfef0078 100644 --- a/src/cmd/compile/internal/escape/escape.go +++ b/src/cmd/compile/internal/escape/escape.go @@ -563,7 +563,10 @@ func (b *batch) rewriteWithLiterals(n ir.Node, fn *ir.Func) { if ro == nil { base.Fatalf("no ReassignOracle for function %v with closure parent %v", fn, fn.ClosureParent) } - if s := ro.StaticValue(*r); s.Op() == ir.OLITERAL { + + s := ro.StaticValue(*r) + switch s.Op() { + case ir.OLITERAL: lit, ok := s.(*ir.BasicLit) if !ok || lit.Val().Kind() != constant.Int { base.Fatalf("unexpected BasicLit Kind") @@ -577,6 +580,14 @@ func (b *batch) rewriteWithLiterals(n ir.Node, fn *ir.Func) { assignTemp(n.Pos(), *r, n.PtrInit()) *r = ir.NewBasicLit(n.Pos(), (*r).Type(), lit.Val()) } + case ir.OLEN: + x := ro.StaticValue(s.(*ir.UnaryExpr).X) + if x.Op() == ir.OSLICELIT { + x := x.(*ir.CompLitExpr) + // Preserve any side effects of the original expression, then update the value. + assignTemp(n.Pos(), *r, n.PtrInit()) + *r = ir.NewBasicLit(n.Pos(), types.Types[types.TINT], constant.MakeInt64(x.Len)) + } } } case ir.OCONVIFACE: diff --git a/test/escape_make_non_const.go b/test/escape_make_non_const.go index 7a9b28d5e37a7e..11854ac4f4731a 100644 --- a/test/escape_make_non_const.go +++ b/test/escape_make_non_const.go @@ -106,3 +106,18 @@ type m struct { func newM(l int) m { // ERROR "can inline" return m{make(map[string]int, l)} // ERROR "make.*escapes to heap" } + +//go:noinline +func testLenOfSliceLit() { + ints := []int{0, 1, 2, 3, 4, 5} // ERROR "\[\]int\{\.\.\.\} does not escape"' + _ = make([]int, len(ints)) // ERROR "make\(\[\]int, 6\) does not escape" + _ = allocLenOf(ints) // ERROR "inlining call", "make\(\[\]int, 6\) does not escape" + + _ = make([]int, 2, len(ints)) // ERROR "make\(\[\]int, 2, 6\) does not escape" + _ = make([]int, len(ints), 2) // ERROR "make\(\[\]int, len\(ints\), 2\) does not escape" + _ = make([]int, 10, len(ints)) // ERROR "make\(\[\]int, 10, 6\) does not escape" +} + +func allocLenOf(s []int) []int { // ERROR "can inline" "s does not escape" + return make([]int, len(s)) // ERROR "escapes to heap" +} From 8c68a1c1abade565c6719159858e76f9b122ddc8 Mon Sep 17 00:00:00 2001 From: Vlad Saioc Date: Thu, 2 Oct 2025 11:57:58 +0000 Subject: [PATCH 034/229] runtime,net/http/pprof: goroutine leak detection by using the garbage collector Proposal #74609 Change-Id: I97a754b128aac1bc5b7b9ab607fcd5bb390058c8 GitHub-Last-Rev: 60f2a192badf415112246de8bc6c0084085314f6 GitHub-Pull-Request: golang/go#74622 Reviewed-on: https://go-review.googlesource.com/c/go/+/688335 LUCI-TryBot-Result: Go LUCI Reviewed-by: t hepudds Auto-Submit: Michael Knyszek Reviewed-by: Michael Knyszek Reviewed-by: Carlos Amedee --- src/cmd/link/internal/loader/loader.go | 3 + .../exp_goroutineleakprofile_off.go | 8 + .../exp_goroutineleakprofile_on.go | 8 + src/internal/goexperiment/flags.go | 3 + src/net/http/pprof/pprof.go | 8 + src/runtime/chan.go | 32 +- src/runtime/crash_test.go | 16 + src/runtime/goroutineleakprofile_test.go | 595 ++++++ src/runtime/mbitmap.go | 22 + src/runtime/mgc.go | 306 ++- src/runtime/mgcmark.go | 105 +- src/runtime/mgcmark_greenteagc.go | 2 +- src/runtime/mgcmark_nogreenteagc.go | 2 +- src/runtime/mprof.go | 56 + src/runtime/pprof/pprof.go | 45 +- src/runtime/pprof/runtime.go | 6 + src/runtime/preempt.go | 3 +- src/runtime/proc.go | 16 +- src/runtime/runtime2.go | 121 +- src/runtime/select.go | 12 +- src/runtime/sema.go | 27 +- src/runtime/sizeof_test.go | 2 +- src/runtime/stack.go | 17 +- .../commonpatterns.go | 277 +++ .../testgoroutineleakprofile/goker/LICENSE | 21 + .../testgoroutineleakprofile/goker/README.md | 1847 +++++++++++++++++ .../goker/cockroach10214.go | 145 ++ .../goker/cockroach1055.go | 115 + .../goker/cockroach10790.go | 98 + .../goker/cockroach13197.go | 82 + .../goker/cockroach13755.go | 66 + .../goker/cockroach1462.go | 167 ++ .../goker/cockroach16167.go | 108 + .../goker/cockroach18101.go | 60 + .../goker/cockroach2448.go | 125 ++ .../goker/cockroach24808.go | 78 + .../goker/cockroach25456.go | 92 + .../goker/cockroach35073.go | 124 ++ .../goker/cockroach35931.go | 135 ++ .../goker/cockroach3710.go | 122 ++ .../goker/cockroach584.go | 62 + .../goker/cockroach6181.go | 87 + .../goker/cockroach7504.go | 183 ++ .../goker/cockroach9935.go | 77 + .../goker/etcd10492.go | 72 + .../goker/etcd5509.go | 126 ++ .../goker/etcd6708.go | 100 + .../goker/etcd6857.go | 81 + .../goker/etcd6873.go | 98 + .../goker/etcd7492.go | 163 ++ .../goker/etcd7902.go | 87 + .../goker/grpc1275.go | 111 + .../goker/grpc1424.go | 105 + .../goker/grpc1460.go | 84 + .../goker/grpc3017.go | 123 ++ .../testgoroutineleakprofile/goker/grpc660.go | 65 + .../testgoroutineleakprofile/goker/grpc795.go | 74 + .../testgoroutineleakprofile/goker/grpc862.go | 105 + .../goker/hugo3251.go | 81 + .../goker/hugo5379.go | 317 +++ .../goker/istio16224.go | 129 ++ .../goker/istio17860.go | 144 ++ .../goker/istio18454.go | 154 ++ .../goker/kubernetes10182.go | 95 + .../goker/kubernetes11298.go | 118 ++ .../goker/kubernetes13135.go | 166 ++ .../goker/kubernetes1321.go | 100 + .../goker/kubernetes25331.go | 72 + .../goker/kubernetes26980.go | 87 + .../goker/kubernetes30872.go | 223 ++ .../goker/kubernetes38669.go | 83 + .../goker/kubernetes5316.go | 68 + .../goker/kubernetes58107.go | 108 + .../goker/kubernetes62464.go | 120 ++ .../goker/kubernetes6632.go | 86 + .../goker/kubernetes70277.go | 97 + .../testgoroutineleakprofile/goker/main.go | 39 + .../goker/moby17176.go | 68 + .../goker/moby21233.go | 146 ++ .../goker/moby25384.go | 59 + .../goker/moby27782.go | 242 +++ .../goker/moby28462.go | 125 ++ .../goker/moby30408.go | 67 + .../goker/moby33781.go | 71 + .../goker/moby36114.go | 53 + .../goker/moby4951.go | 101 + .../goker/moby7559.go | 55 + .../goker/serving2137.go | 122 ++ .../goker/syncthing4829.go | 87 + .../goker/syncthing5795.go | 103 + .../testdata/testgoroutineleakprofile/main.go | 39 + .../testgoroutineleakprofile/simple.go | 253 +++ .../testgoroutineleakprofile/stresstests.go | 89 + src/runtime/traceback.go | 6 +- src/runtime/tracestatus.go | 2 +- 95 files changed, 10766 insertions(+), 89 deletions(-) create mode 100644 src/internal/goexperiment/exp_goroutineleakprofile_off.go create mode 100644 src/internal/goexperiment/exp_goroutineleakprofile_on.go create mode 100644 src/runtime/goroutineleakprofile_test.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/commonpatterns.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/LICENSE create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/README.md create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach10214.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1055.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach10790.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach13197.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach13755.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1462.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach16167.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach18101.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach2448.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach24808.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach25456.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach35073.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach35931.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach3710.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach584.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach6181.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach7504.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/cockroach9935.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/etcd10492.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/etcd5509.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/etcd6708.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/etcd6857.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/etcd6873.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/etcd7492.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/etcd7902.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/grpc1275.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/grpc1424.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/grpc1460.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/grpc3017.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/grpc660.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/grpc795.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/grpc862.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/hugo3251.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/hugo5379.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/istio16224.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/istio17860.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/istio18454.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes10182.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes11298.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes13135.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes1321.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes25331.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes26980.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes30872.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes38669.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes5316.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes58107.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes62464.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes6632.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes70277.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/main.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby17176.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby21233.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby25384.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby27782.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby28462.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby30408.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby33781.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby36114.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby4951.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/moby7559.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/serving2137.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/syncthing4829.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/goker/syncthing5795.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/main.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/simple.go create mode 100644 src/runtime/testdata/testgoroutineleakprofile/stresstests.go diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go index 103dad03001263..0ed20d1becbb03 100644 --- a/src/cmd/link/internal/loader/loader.go +++ b/src/cmd/link/internal/loader/loader.go @@ -2450,6 +2450,9 @@ var blockedLinknames = map[string][]string{ "sync_test.runtime_blockUntilEmptyCleanupQueue": {"sync_test"}, "time.runtimeIsBubbled": {"time"}, "unique.runtime_blockUntilEmptyCleanupQueue": {"unique"}, + // Experimental features + "runtime.goroutineLeakGC": {"runtime/pprof"}, + "runtime.goroutineleakcount": {"runtime/pprof"}, // Others "net.newWindowsFile": {"net"}, // pushed from os "testing/synctest.testingSynctestTest": {"testing/synctest"}, // pushed from testing diff --git a/src/internal/goexperiment/exp_goroutineleakprofile_off.go b/src/internal/goexperiment/exp_goroutineleakprofile_off.go new file mode 100644 index 00000000000000..63eafe9e6c74db --- /dev/null +++ b/src/internal/goexperiment/exp_goroutineleakprofile_off.go @@ -0,0 +1,8 @@ +// Code generated by mkconsts.go. DO NOT EDIT. + +//go:build !goexperiment.goroutineleakprofile + +package goexperiment + +const GoroutineLeakProfile = false +const GoroutineLeakProfileInt = 0 diff --git a/src/internal/goexperiment/exp_goroutineleakprofile_on.go b/src/internal/goexperiment/exp_goroutineleakprofile_on.go new file mode 100644 index 00000000000000..28a662eceb46f8 --- /dev/null +++ b/src/internal/goexperiment/exp_goroutineleakprofile_on.go @@ -0,0 +1,8 @@ +// Code generated by mkconsts.go. DO NOT EDIT. + +//go:build goexperiment.goroutineleakprofile + +package goexperiment + +const GoroutineLeakProfile = true +const GoroutineLeakProfileInt = 1 diff --git a/src/internal/goexperiment/flags.go b/src/internal/goexperiment/flags.go index 84dbf594b8792a..232a17135d2cc5 100644 --- a/src/internal/goexperiment/flags.go +++ b/src/internal/goexperiment/flags.go @@ -118,4 +118,7 @@ type Flags struct { // SizeSpecializedMalloc enables malloc implementations that are specialized per size class. SizeSpecializedMalloc bool + + // GoroutineLeakProfile enables the collection of goroutine leak profiles. + GoroutineLeakProfile bool } diff --git a/src/net/http/pprof/pprof.go b/src/net/http/pprof/pprof.go index 635d3ad9d9f132..e5a46ed253cf8b 100644 --- a/src/net/http/pprof/pprof.go +++ b/src/net/http/pprof/pprof.go @@ -77,6 +77,7 @@ import ( "fmt" "html" "internal/godebug" + "internal/goexperiment" "internal/profile" "io" "log" @@ -353,6 +354,7 @@ func collectProfile(p *pprof.Profile) (*profile.Profile, error) { var profileSupportsDelta = map[handler]bool{ "allocs": true, "block": true, + "goroutineleak": true, "goroutine": true, "heap": true, "mutex": true, @@ -372,6 +374,12 @@ var profileDescriptions = map[string]string{ "trace": "A trace of execution of the current program. You can specify the duration in the seconds GET parameter. After you get the trace file, use the go tool trace command to investigate the trace.", } +func init() { + if goexperiment.GoroutineLeakProfile { + profileDescriptions["goroutineleak"] = "Stack traces of all leaked goroutines. Use debug=2 as a query parameter to export in the same format as an unrecovered panic." + } +} + type profileEntry struct { Name string Href string diff --git a/src/runtime/chan.go b/src/runtime/chan.go index 639d29dc8337f0..3320c248b458b6 100644 --- a/src/runtime/chan.go +++ b/src/runtime/chan.go @@ -263,11 +263,11 @@ func chansend(c *hchan, ep unsafe.Pointer, block bool, callerpc uintptr) bool { } // No stack splits between assigning elem and enqueuing mysg // on gp.waiting where copystack can find it. - mysg.elem = ep + mysg.elem.set(ep) mysg.waitlink = nil mysg.g = gp mysg.isSelect = false - mysg.c = c + mysg.c.set(c) gp.waiting = mysg gp.param = nil c.sendq.enqueue(mysg) @@ -298,7 +298,7 @@ func chansend(c *hchan, ep unsafe.Pointer, block bool, callerpc uintptr) bool { if mysg.releasetime > 0 { blockevent(mysg.releasetime-t0, 2) } - mysg.c = nil + mysg.c.set(nil) releaseSudog(mysg) if closed { if c.closed == 0 { @@ -336,9 +336,9 @@ func send(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func(), skip int) { c.sendx = c.recvx // c.sendx = (c.sendx+1) % c.dataqsiz } } - if sg.elem != nil { + if sg.elem.get() != nil { sendDirect(c.elemtype, sg, ep) - sg.elem = nil + sg.elem.set(nil) } gp := sg.g unlockf() @@ -395,7 +395,7 @@ func sendDirect(t *_type, sg *sudog, src unsafe.Pointer) { // Once we read sg.elem out of sg, it will no longer // be updated if the destination's stack gets copied (shrunk). // So make sure that no preemption points can happen between read & use. - dst := sg.elem + dst := sg.elem.get() typeBitsBulkBarrier(t, uintptr(dst), uintptr(src), t.Size_) // No need for cgo write barrier checks because dst is always // Go memory. @@ -406,7 +406,7 @@ func recvDirect(t *_type, sg *sudog, dst unsafe.Pointer) { // dst is on our stack or the heap, src is on another stack. // The channel is locked, so src will not move during this // operation. - src := sg.elem + src := sg.elem.get() typeBitsBulkBarrier(t, uintptr(dst), uintptr(src), t.Size_) memmove(dst, src, t.Size_) } @@ -441,9 +441,9 @@ func closechan(c *hchan) { if sg == nil { break } - if sg.elem != nil { - typedmemclr(c.elemtype, sg.elem) - sg.elem = nil + if sg.elem.get() != nil { + typedmemclr(c.elemtype, sg.elem.get()) + sg.elem.set(nil) } if sg.releasetime != 0 { sg.releasetime = cputicks() @@ -463,7 +463,7 @@ func closechan(c *hchan) { if sg == nil { break } - sg.elem = nil + sg.elem.set(nil) if sg.releasetime != 0 { sg.releasetime = cputicks() } @@ -642,13 +642,13 @@ func chanrecv(c *hchan, ep unsafe.Pointer, block bool) (selected, received bool) } // No stack splits between assigning elem and enqueuing mysg // on gp.waiting where copystack can find it. - mysg.elem = ep + mysg.elem.set(ep) mysg.waitlink = nil gp.waiting = mysg mysg.g = gp mysg.isSelect = false - mysg.c = c + mysg.c.set(c) gp.param = nil c.recvq.enqueue(mysg) if c.timer != nil { @@ -680,7 +680,7 @@ func chanrecv(c *hchan, ep unsafe.Pointer, block bool) (selected, received bool) } success := mysg.success gp.param = nil - mysg.c = nil + mysg.c.set(nil) releaseSudog(mysg) return true, success } @@ -727,14 +727,14 @@ func recv(c *hchan, sg *sudog, ep unsafe.Pointer, unlockf func(), skip int) { typedmemmove(c.elemtype, ep, qp) } // copy data from sender to queue - typedmemmove(c.elemtype, qp, sg.elem) + typedmemmove(c.elemtype, qp, sg.elem.get()) c.recvx++ if c.recvx == c.dataqsiz { c.recvx = 0 } c.sendx = c.recvx // c.sendx = (c.sendx+1) % c.dataqsiz } - sg.elem = nil + sg.elem.set(nil) gp := sg.g unlockf() gp.param = unsafe.Pointer(sg) diff --git a/src/runtime/crash_test.go b/src/runtime/crash_test.go index 2db86e0562d6ae..2b8ca549ad84f2 100644 --- a/src/runtime/crash_test.go +++ b/src/runtime/crash_test.go @@ -186,6 +186,22 @@ func buildTestProg(t *testing.T, binary string, flags ...string) (string, error) t.Logf("running %v", cmd) cmd.Dir = "testdata/" + binary cmd = testenv.CleanCmdEnv(cmd) + + // If tests need any experimental flags, add them here. + // + // TODO(vsaioc): Remove `goroutineleakprofile` once the feature is no longer experimental. + edited := false + for i := range cmd.Env { + e := cmd.Env[i] + if _, vars, ok := strings.Cut(e, "GOEXPERIMENT="); ok { + cmd.Env[i] = "GOEXPERIMENT=" + vars + ",goroutineleakprofile" + edited, _ = true, vars + } + } + if !edited { + cmd.Env = append(cmd.Env, "GOEXPERIMENT=goroutineleakprofile") + } + out, err := cmd.CombinedOutput() if err != nil { target.err = fmt.Errorf("building %s %v: %v\n%s", binary, flags, err, out) diff --git a/src/runtime/goroutineleakprofile_test.go b/src/runtime/goroutineleakprofile_test.go new file mode 100644 index 00000000000000..9857d725deef32 --- /dev/null +++ b/src/runtime/goroutineleakprofile_test.go @@ -0,0 +1,595 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package runtime_test + +import ( + "fmt" + "regexp" + "strings" + "testing" +) + +func TestGoroutineLeakProfile(t *testing.T) { + // Goroutine leak test case. + // + // Test cases can be configured with test name, the name of the entry point function, + // a set of expected leaks identified by regular expressions, and the number of times + // the test should be repeated. + // + // Repeated runs reduce flakiness in some tests. + type testCase struct { + name string + simple bool + repetitions int + expectedLeaks map[*regexp.Regexp]bool + + // flakyLeaks are goroutine leaks that are too flaky to be reliably detected. + // Still, they might pop up every once in a while. The test will pass regardless + // if they occur or nor, as they are not unexpected. + // + // Note that all flaky leaks are true positives, i.e. real goroutine leaks, + // and it is only their detection that is unreliable due to scheduling + // non-determinism. + flakyLeaks map[*regexp.Regexp]struct{} + } + + // makeAnyTest is a short-hand for creating test cases. + // Each of the leaks in the list is identified by a regular expression. + // If a leak is flaky, it is added to the flakyLeaks map. + makeAnyTest := func(name string, flaky bool, repetitions int, leaks ...string) testCase { + tc := testCase{ + name: name, + expectedLeaks: make(map[*regexp.Regexp]bool, len(leaks)), + flakyLeaks: make(map[*regexp.Regexp]struct{}, len(leaks)), + // Make sure the test is repeated at least once. + repetitions: repetitions | 1, + } + + for _, leak := range leaks { + if !flaky { + tc.expectedLeaks[regexp.MustCompile(leak)] = false + } else { + tc.flakyLeaks[regexp.MustCompile(leak)] = struct{}{} + } + } + + return tc + } + + // makeTest is a short-hand for creating non-flaky test cases. + makeTest := func(name string, leaks ...string) testCase { + tcase := makeAnyTest(name, false, 2, leaks...) + tcase.simple = true + return tcase + } + + // makeFlakyTest is a short-hand for creating flaky test cases. + makeFlakyTest := func(name string, leaks ...string) testCase { + if testing.Short() { + return makeAnyTest(name, true, 2, leaks...) + } + return makeAnyTest(name, true, 10, leaks...) + } + + goroutineHeader := regexp.MustCompile(`goroutine \d+ \[`) + + // extractLeaks takes the output of a test and splits it into a + // list of strings denoting goroutine leaks. + // + // If the input is: + // + // goroutine 1 [wait reason (leaked)]: + // main.leaked() + // ./testdata/testgoroutineleakprofile/foo.go:37 +0x100 + // created by main.main() + // ./testdata/testgoroutineleakprofile/main.go:10 +0x20 + // + // goroutine 2 [wait reason (leaked)]: + // main.leaked2() + // ./testdata/testgoroutineleakprofile/foo.go:37 +0x100 + // created by main.main() + // ./testdata/testgoroutineleakprofile/main.go:10 +0x20 + // + // The output is (as a list of strings): + // + // leaked() [wait reason] + // leaked2() [wait reason] + extractLeaks := func(output string) []string { + stacks := strings.Split(output, "\n\ngoroutine") + var leaks []string + for _, stack := range stacks { + lines := strings.Split(stack, "\n") + if len(lines) < 5 { + // Expecting at least the following lines (where n=len(lines)-1): + // + // [0] goroutine n [wait reason (leaked)] + // ... + // [n-3] bottom.leak.frame(...) + // [n-2] ./bottom/leak/frame/source.go:line + // [n-1] created by go.instruction() + // [n] ./go/instruction/source.go:line + continue + } + + if !strings.Contains(lines[0], "(leaked)") { + // Ignore non-leaked goroutines. + continue + } + + // Get the wait reason from the goroutine header. + header := lines[0] + waitReason := goroutineHeader.ReplaceAllString(header, "[") + waitReason = strings.ReplaceAll(waitReason, " (leaked)", "") + + // Get the function name from the stack trace (should be two lines above `created by`). + var funcName string + for i := len(lines) - 1; i >= 0; i-- { + if strings.Contains(lines[i], "created by") { + funcName = strings.TrimPrefix(lines[i-2], "main.") + break + } + } + if funcName == "" { + t.Fatalf("failed to extract function name from stack trace: %s", lines) + } + + leaks = append(leaks, funcName+" "+waitReason) + } + return leaks + } + + // Micro tests involve very simple leaks for each type of concurrency primitive operation. + microTests := []testCase{ + makeTest("NilRecv", + `NilRecv\.func1\(.* \[chan receive \(nil chan\)\]`, + ), + makeTest("NilSend", + `NilSend\.func1\(.* \[chan send \(nil chan\)\]`, + ), + makeTest("SelectNoCases", + `SelectNoCases\.func1\(.* \[select \(no cases\)\]`, + ), + makeTest("ChanRecv", + `ChanRecv\.func1\(.* \[chan receive\]`, + ), + makeTest("ChanSend", + `ChanSend\.func1\(.* \[chan send\]`, + ), + makeTest("Select", + `Select\.func1\(.* \[select\]`, + ), + makeTest("WaitGroup", + `WaitGroup\.func1\(.* \[sync\.WaitGroup\.Wait\]`, + ), + makeTest("MutexStack", + `MutexStack\.func1\(.* \[sync\.Mutex\.Lock\]`, + ), + makeTest("MutexHeap", + `MutexHeap\.func1.1\(.* \[sync\.Mutex\.Lock\]`, + ), + makeTest("Cond", + `Cond\.func1\(.* \[sync\.Cond\.Wait\]`, + ), + makeTest("RWMutexRLock", + `RWMutexRLock\.func1\(.* \[sync\.RWMutex\.RLock\]`, + ), + makeTest("RWMutexLock", + `RWMutexLock\.func1\(.* \[sync\.(RW)?Mutex\.Lock\]`, + ), + makeTest("Mixed", + `Mixed\.func1\(.* \[sync\.WaitGroup\.Wait\]`, + `Mixed\.func1.1\(.* \[chan send\]`, + ), + makeTest("NoLeakGlobal"), + } + + // Stress tests are flaky and we do not strictly care about their output. + // They are only intended to stress the goroutine leak detector and profiling + // infrastructure in interesting ways. + stressTestCases := []testCase{ + makeFlakyTest("SpawnGC", + `spawnGC.func1\(.* \[chan receive\]`, + ), + makeTest("DaisyChain"), + } + + // Common goroutine leak patterns. + // Extracted from "Unveiling and Vanquishing Goroutine Leaks in Enterprise Microservices: A Dynamic Analysis Approach" + // doi:10.1109/CGO57630.2024.10444835 + patternTestCases := []testCase{ + makeTest("NoCloseRange", + `noCloseRange\(.* \[chan send\]`, + `noCloseRange\.func1\(.* \[chan receive\]`, + ), + makeTest("MethodContractViolation", + `worker\.Start\.func1\(.* \[select\]`, + ), + makeTest("DoubleSend", + `DoubleSend\.func3\(.* \[chan send\]`, + ), + makeTest("EarlyReturn", + `earlyReturn\.func1\(.* \[chan send\]`, + ), + makeTest("NCastLeak", + `nCastLeak\.func1\(.* \[chan send\]`, + `NCastLeak\.func2\(.* \[chan receive\]`, + ), + makeTest("Timeout", + // (vsaioc): Timeout is *theoretically* flaky, but the + // pseudo-random choice for select case branches makes it + // practically impossible for it to fail. + `timeout\.func1\(.* \[chan send\]`, + ), + } + + // GoKer tests from "GoBench: A Benchmark Suite of Real-World Go Concurrency Bugs". + // Refer to testdata/testgoroutineleakprofile/goker/README.md. + // + // This list is curated for tests that are not excessively flaky. + // Some tests are also excluded because they are redundant. + // + // TODO(vsaioc): Some of these might be removable (their patterns may overlap). + gokerTestCases := []testCase{ + makeFlakyTest("Cockroach584", + `Cockroach584\.func2\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Cockroach1055", + `Cockroach1055\.func2\(.* \[chan receive\]`, + `Cockroach1055\.func2\.2\(.* \[sync\.WaitGroup\.Wait\]`, + `Cockroach1055\.func2\.1\(.* \[chan receive\]`, + `Cockroach1055\.func2\.1\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Cockroach1462", + `\(\*Stopper_cockroach1462\)\.RunWorker\.func1\(.* \[chan send\]`, + `Cockroach1462\.func2\(.* \[sync\.WaitGroup\.Wait\]`, + ), + makeFlakyTest("Cockroach2448", + `\(\*Store_cockroach2448\)\.processRaft\(.* \[select\]`, + `\(\*state_cockroach2448\)\.start\(.* \[select\]`, + ), + makeFlakyTest("Cockroach3710", + `\(\*Store_cockroach3710\)\.ForceRaftLogScanAndProcess\(.* \[sync\.RWMutex\.RLock\]`, + `\(\*Store_cockroach3710\)\.processRaft\.func1\(.* \[sync\.RWMutex\.Lock\]`, + ), + makeFlakyTest("Cockroach6181", + `testRangeCacheCoalescedRequests_cockroach6181\(.* \[sync\.WaitGroup\.Wait\]`, + `testRangeCacheCoalescedRequests_cockroach6181\.func1\.1\(.* \[sync\.(RW)?Mutex\.Lock\]`, + `testRangeCacheCoalescedRequests_cockroach6181\.func1\.1\(.* \[sync\.RWMutex\.RLock\]`, + ), + makeTest("Cockroach7504", + `Cockroach7504\.func2\.1.* \[sync\.Mutex\.Lock\]`, + `Cockroach7504\.func2\.2.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Cockroach9935", + `\(\*loggingT_cockroach9935\)\.outputLogEntry\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Cockroach10214", + `\(*Store_cockroach10214\)\.sendQueuedHeartbeats\(.* \[sync\.Mutex\.Lock\]`, + `\(*Replica_cockroach10214\)\.tick\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Cockroach10790", + `\(\*Replica_cockroach10790\)\.beginCmds\.func1\(.* \[chan receive\]`, + ), + makeTest("Cockroach13197", + `\(\*Tx_cockroach13197\)\.awaitDone\(.* \[chan receive\]`, + ), + makeTest("Cockroach13755", + `\(\*Rows_cockroach13755\)\.awaitDone\(.* \[chan receive\]`, + ), + makeFlakyTest("Cockroach16167", + `Cockroach16167\.func2\(.* \[sync\.RWMutex\.RLock\]`, + `\(\*Executor_cockroach16167\)\.Start\(.* \[sync\.RWMutex\.Lock\]`, + ), + makeFlakyTest("Cockroach18101", + `restore_cockroach18101\.func1\(.* \[chan send\]`, + ), + makeTest("Cockroach24808", + `Cockroach24808\.func2\(.* \[chan send\]`, + ), + makeTest("Cockroach25456", + `Cockroach25456\.func2\(.* \[chan receive\]`, + ), + makeTest("Cockroach35073", + `Cockroach35073\.func2.1\(.* \[chan send\]`, + `Cockroach35073\.func2\(.* \[chan send\]`, + ), + makeTest("Cockroach35931", + `Cockroach35931\.func2\(.* \[chan send\]`, + ), + makeTest("Etcd5509", + `Etcd5509\.func2\(.* \[sync\.RWMutex\.Lock\]`, + ), + makeTest("Etcd6708", + `Etcd6708\.func2\(.* \[sync\.RWMutex\.RLock\]`, + ), + makeFlakyTest("Etcd6857", + `\(\*node_etcd6857\)\.Status\(.* \[chan send\]`, + ), + makeFlakyTest("Etcd6873", + `\(\*watchBroadcasts_etcd6873\)\.stop\(.* \[chan receive\]`, + `newWatchBroadcasts_etcd6873\.func1\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Etcd7492", + `Etcd7492\.func2\(.* \[sync\.WaitGroup\.Wait\]`, + `Etcd7492\.func2\.1\(.* \[chan send\]`, + `\(\*simpleTokenTTLKeeper_etcd7492\)\.run\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Etcd7902", + `doRounds_etcd7902\.func1\(.* \[chan receive\]`, + `doRounds_etcd7902\.func1\(.* \[sync\.Mutex\.Lock\]`, + `runElectionFunc_etcd7902\(.* \[sync\.WaitGroup\.Wait\]`, + ), + makeTest("Etcd10492", + `Etcd10492\.func2\(.* \[sync\.Mutex\.Lock\]`, + ), + makeTest("Grpc660", + `\(\*benchmarkClient_grpc660\)\.doCloseLoopUnary\.func1\(.* \[chan send\]`, + ), + makeFlakyTest("Grpc795", + `\(\*Server_grpc795\)\.Serve\(.* \[sync\.Mutex\.Lock\]`, + `testServerGracefulStopIdempotent_grpc795\(.* \[sync\.Mutex\.Lock\]`, + ), + makeTest("Grpc862", + `DialContext_grpc862\.func2\(.* \[chan receive\]`), + makeTest("Grpc1275", + `testInflightStreamClosing_grpc1275\.func1\(.* \[chan receive\]`), + makeTest("Grpc1424", + `DialContext_grpc1424\.func1\(.* \[chan receive\]`), + makeFlakyTest("Grpc1460", + `\(\*http2Client_grpc1460\)\.keepalive\(.* \[chan receive\]`, + `\(\*http2Client_grpc1460\)\.NewStream\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Grpc3017", + // grpc/3017 involves a goroutine leak that also simultaneously engages many GC assists. + `Grpc3017\.func2\(.* \[chan receive\]`, + `Grpc3017\.func2\.1\(.* \[sync\.Mutex\.Lock\]`, + `\(\*lbCacheClientConn_grpc3017\)\.RemoveSubConn\.func1\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Hugo3251", + `Hugo3251\.func2\(.* \[sync\.WaitGroup\.Wait\]`, + `Hugo3251\.func2\.1\(.* \[sync\.Mutex\.Lock\]`, + `Hugo3251\.func2\.1\(.* \[sync\.RWMutex\.RLock\]`, + ), + makeFlakyTest("Hugo5379", + `\(\*Page_hugo5379\)\.initContent\.func1\.1\(.* \[sync\.Mutex\.Lock\]`, + `pageRenderer_hugo5379\(.* \[sync\.Mutex\.Lock\]`, + `Hugo5379\.func2\(.* \[sync\.WaitGroup\.Wait\]`, + ), + makeFlakyTest("Istio16224", + `Istio16224\.func2\(.* \[sync\.Mutex\.Lock\]`, + `\(\*controller_istio16224\)\.Run\(.* \[chan send\]`, + `\(\*controller_istio16224\)\.Run\(.* \[chan receive\]`, + ), + makeFlakyTest("Istio17860", + `\(\*agent_istio17860\)\.runWait\(.* \[chan send\]`, + ), + makeFlakyTest("Istio18454", + `\(\*Worker_istio18454\)\.Start\.func1\(.* \[chan receive\]`, + `\(\*Worker_istio18454\)\.Start\.func1\(.* \[chan send\]`, + ), + // NOTE(vsaioc): + // Kubernetes/1321 is excluded due to a race condition in the original program + // that may, in extremely rare cases, lead to nil pointer dereference crashes. + // (Reproducible even with regular GC). Only kept here for posterity. + // + // makeTest(testCase{name: "Kubernetes1321"}, + // `NewMux_kubernetes1321\.gowrap1\(.* \[chan send\]`, + // `testMuxWatcherClose_kubernetes1321\(.* \[sync\.Mutex\.Lock\]`), + makeTest("Kubernetes5316", + `finishRequest_kubernetes5316\.func1\(.* \[chan send\]`, + ), + makeFlakyTest("Kubernetes6632", + `\(\*idleAwareFramer_kubernetes6632\)\.monitor\(.* \[sync\.Mutex\.Lock\]`, + `\(\*idleAwareFramer_kubernetes6632\)\.WriteFrame\(.* \[chan send\]`, + ), + makeFlakyTest("Kubernetes10182", + `\(\*statusManager_kubernetes10182\)\.Start\.func1\(.* \[sync\.Mutex\.Lock\]`, + `\(\*statusManager_kubernetes10182\)\.SetPodStatus\(.* \[chan send\]`, + ), + makeFlakyTest("Kubernetes11298", + `After_kubernetes11298\.func1\(.* \[chan receive\]`, + `After_kubernetes11298\.func1\(.* \[sync\.Cond\.Wait\]`, + `Kubernetes11298\.func2\(.* \[chan receive\]`, + ), + makeFlakyTest("Kubernetes13135", + `Util_kubernetes13135\(.* \[sync\.Mutex\.Lock\]`, + `\(\*WatchCache_kubernetes13135\)\.Add\(.* \[sync\.Mutex\.Lock\]`, + ), + makeTest("Kubernetes25331", + `\(\*watchChan_kubernetes25331\)\.run\(.* \[chan send\]`, + ), + makeFlakyTest("Kubernetes26980", + `Kubernetes26980\.func2\(.* \[chan receive\]`, + `Kubernetes26980\.func2\.1\(.* \[sync\.Mutex\.Lock\]`, + `\(\*processorListener_kubernetes26980\)\.pop\(.* \[chan receive\]`, + ), + makeFlakyTest("Kubernetes30872", + `\(\*DelayingDeliverer_kubernetes30872\)\.StartWithHandler\.func1\(.* \[sync\.Mutex\.Lock\]`, + `\(\*Controller_kubernetes30872\)\.Run\(.* \[sync\.Mutex\.Lock\]`, + `\(\*NamespaceController_kubernetes30872\)\.Run\.func1\(.* \[sync\.Mutex\.Lock\]`, + ), + makeTest("Kubernetes38669", + `\(\*cacheWatcher_kubernetes38669\)\.process\(.* \[chan send\]`, + ), + makeFlakyTest("Kubernetes58107", + `\(\*ResourceQuotaController_kubernetes58107\)\.worker\(.* \[sync\.Cond\.Wait\]`, + `\(\*ResourceQuotaController_kubernetes58107\)\.worker\(.* \[sync\.RWMutex\.RLock\]`, + `\(\*ResourceQuotaController_kubernetes58107\)\.Sync\(.* \[sync\.RWMutex\.Lock\]`, + ), + makeFlakyTest("Kubernetes62464", + `\(\*manager_kubernetes62464\)\.reconcileState\(.* \[sync\.RWMutex\.RLock\]`, + `\(\*staticPolicy_kubernetes62464\)\.RemoveContainer\(.* \[sync\.(RW)?Mutex\.Lock\]`, + ), + makeFlakyTest("Kubernetes70277", + `Kubernetes70277\.func2\(.* \[chan receive\]`, + ), + makeFlakyTest("Moby4951", + `\(\*DeviceSet_moby4951\)\.DeleteDevice\(.* \[sync\.Mutex\.Lock\]`, + ), + makeTest("Moby7559", + `\(\*UDPProxy_moby7559\)\.Run\(.* \[sync\.Mutex\.Lock\]`, + ), + makeTest("Moby17176", + `testDevmapperLockReleasedDeviceDeletion_moby17176\.func1\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Moby21233", + `\(\*Transfer_moby21233\)\.Watch\.func1\(.* \[chan send\]`, + `\(\*Transfer_moby21233\)\.Watch\.func1\(.* \[select\]`, + `testTransfer_moby21233\(.* \[chan receive\]`, + ), + makeTest("Moby25348", + `\(\*Manager_moby25348\)\.init\(.* \[sync\.WaitGroup\.Wait\]`, + ), + makeFlakyTest("Moby27782", + `\(\*JSONFileLogger_moby27782\)\.readLogs\(.* \[sync\.Cond\.Wait\]`, + `\(\*Watcher_moby27782\)\.readEvents\(.* \[select\]`, + ), + makeFlakyTest("Moby28462", + `monitor_moby28462\(.* \[sync\.Mutex\.Lock\]`, + `\(\*Daemon_moby28462\)\.StateChanged\(.* \[chan send\]`, + ), + makeTest("Moby30408", + `Moby30408\.func2\(.* \[chan receive\]`, + `testActive_moby30408\.func1\(.* \[sync\.Cond\.Wait\]`, + ), + makeFlakyTest("Moby33781", + `monitor_moby33781\.func1\(.* \[chan send\]`, + ), + makeFlakyTest("Moby36114", + `\(\*serviceVM_moby36114\)\.hotAddVHDsAtStart\(.* \[sync\.Mutex\.Lock\]`, + ), + makeFlakyTest("Serving2137", + `\(\*Breaker_serving2137\)\.concurrentRequest\.func1\(.* \[chan send\]`, + `\(\*Breaker_serving2137\)\.concurrentRequest\.func1\(.* \[sync\.Mutex\.Lock\]`, + `Serving2137\.func2\(.* \[chan receive\]`, + ), + makeTest("Syncthing4829", + `Syncthing4829\.func2\(.* \[sync\.RWMutex\.RLock\]`, + ), + makeTest("Syncthing5795", + `\(\*rawConnection_syncthing5795\)\.dispatcherLoop\(.* \[chan receive\]`, + `Syncthing5795\.func2.* \[chan receive\]`, + ), + } + + // Combine all test cases into a single list. + testCases := append(microTests, stressTestCases...) + testCases = append(testCases, patternTestCases...) + + // Test cases must not panic or cause fatal exceptions. + failStates := regexp.MustCompile(`fatal|panic`) + + testApp := func(exepath string, testCases []testCase) { + + // Build the test program once. + exe, err := buildTestProg(t, exepath) + if err != nil { + t.Fatal(fmt.Sprintf("building testgoroutineleakprofile failed: %v", err)) + } + + for _, tcase := range testCases { + t.Run(tcase.name, func(t *testing.T) { + t.Parallel() + + cmdEnv := []string{ + "GODEBUG=asyncpreemptoff=1", + "GOEXPERIMENT=greenteagc,goroutineleakprofile", + } + + if tcase.simple { + // If the test is simple, set GOMAXPROCS=1 in order to better + // control the behavior of the scheduler. + cmdEnv = append(cmdEnv, "GOMAXPROCS=1") + } + + var output string + for i := 0; i < tcase.repetitions; i++ { + // Run program for one repetition and get runOutput trace. + runOutput := runBuiltTestProg(t, exe, tcase.name, cmdEnv...) + if len(runOutput) == 0 { + t.Errorf("Test %s produced no output. Is the goroutine leak profile collected?", tcase.name) + } + + // Zero tolerance policy for fatal exceptions or panics. + if failStates.MatchString(runOutput) { + t.Errorf("unexpected fatal exception or panic!\noutput:\n%s\n\n", runOutput) + } + + output += runOutput + "\n\n" + } + + // Extract all the goroutine leaks + foundLeaks := extractLeaks(output) + + // If the test case was not expected to produce leaks, but some were reported, + // stop the test immediately. Zero tolerance policy for false positives. + if len(tcase.expectedLeaks)+len(tcase.flakyLeaks) == 0 && len(foundLeaks) > 0 { + t.Errorf("output:\n%s\n\ngoroutines leaks detected in case with no leaks", output) + } + + unexpectedLeaks := make([]string, 0, len(foundLeaks)) + + // Parse every leak and check if it is expected (maybe as a flaky leak). + LEAKS: + for _, leak := range foundLeaks { + // Check if the leak is expected. + // If it is, check whether it has been encountered before. + var foundNew bool + var leakPattern *regexp.Regexp + + for expectedLeak, ok := range tcase.expectedLeaks { + if expectedLeak.MatchString(leak) { + if !ok { + foundNew = true + } + + leakPattern = expectedLeak + break + } + } + + if foundNew { + // Only bother writing if we found a new leak. + tcase.expectedLeaks[leakPattern] = true + } + + if leakPattern == nil { + // We are dealing with a leak not marked as expected. + // Check if it is a flaky leak. + for flakyLeak := range tcase.flakyLeaks { + if flakyLeak.MatchString(leak) { + // The leak is flaky. Carry on to the next line. + continue LEAKS + } + } + + unexpectedLeaks = append(unexpectedLeaks, leak) + } + } + + missingLeakStrs := make([]string, 0, len(tcase.expectedLeaks)) + for expectedLeak, found := range tcase.expectedLeaks { + if !found { + missingLeakStrs = append(missingLeakStrs, expectedLeak.String()) + } + } + + var errors []error + if len(unexpectedLeaks) > 0 { + errors = append(errors, fmt.Errorf("unexpected goroutine leaks:\n%s\n", strings.Join(unexpectedLeaks, "\n"))) + } + if len(missingLeakStrs) > 0 { + errors = append(errors, fmt.Errorf("missing expected leaks:\n%s\n", strings.Join(missingLeakStrs, ", "))) + } + if len(errors) > 0 { + t.Fatalf("Failed with the following errors:\n%s\n\noutput:\n%s", errors, output) + } + }) + } + } + + testApp("testgoroutineleakprofile", testCases) + testApp("testgoroutineleakprofile/goker", gokerTestCases) +} diff --git a/src/runtime/mbitmap.go b/src/runtime/mbitmap.go index 508de9a115723c..37a92c64bc6ecc 100644 --- a/src/runtime/mbitmap.go +++ b/src/runtime/mbitmap.go @@ -1267,6 +1267,28 @@ func markBitsForSpan(base uintptr) (mbits markBits) { return mbits } +// isMarkedOrNotInHeap returns true if a pointer is in the heap and marked, +// or if the pointer is not in the heap. Used by goroutine leak detection +// to determine if concurrency resources are reachable in memory. +func isMarkedOrNotInHeap(p unsafe.Pointer) bool { + obj, span, objIndex := findObject(uintptr(p), 0, 0) + if obj != 0 { + mbits := span.markBitsForIndex(objIndex) + return mbits.isMarked() + } + + // If we fall through to get here, the object is not in the heap. + // In this case, it is either a pointer to a stack object or a global resource. + // Treat it as reachable in memory by default, to be safe. + // + // TODO(vsaioc): we could be more precise by checking against the stacks + // of runnable goroutines. I don't think this is necessary, based on what we've seen, but + // let's keep the option open in case the runtime evolves. + // This will (naively) lead to quadratic blow-up for goroutine leak detection, + // but if it is only run on demand, maybe the extra cost is not a show-stopper. + return true +} + // advance advances the markBits to the next object in the span. func (m *markBits) advance() { if m.mask == 1<<7 { diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go index 68cbfda5000573..b13ec845fc401f 100644 --- a/src/runtime/mgc.go +++ b/src/runtime/mgc.go @@ -376,8 +376,8 @@ type workType struct { // (and thus 8-byte alignment even on 32-bit architectures). bytesMarked uint64 - markrootNext uint32 // next markroot job - markrootJobs uint32 // number of markroot jobs + markrootNext atomic.Uint32 // next markroot job + markrootJobs atomic.Uint32 // number of markroot jobs nproc uint32 tstart int64 @@ -385,17 +385,44 @@ type workType struct { // Number of roots of various root types. Set by gcPrepareMarkRoots. // - // nStackRoots == len(stackRoots), but we have nStackRoots for - // consistency. - nDataRoots, nBSSRoots, nSpanRoots, nStackRoots int + // During normal GC cycle, nStackRoots == nMaybeRunnableStackRoots == len(stackRoots); + // during goroutine leak detection, nMaybeRunnableStackRoots is the number of stackRoots + // scheduled for marking. + // In both variants, nStackRoots == len(stackRoots). + nDataRoots, nBSSRoots, nSpanRoots, nStackRoots, nMaybeRunnableStackRoots int + + // The following fields monitor the GC phase of the current cycle during + // goroutine leak detection. + goroutineLeak struct { + // Once set, it indicates that the GC will perform goroutine leak detection during + // the next GC cycle; it is set by goroutineLeakGC and unset during gcStart. + pending atomic.Bool + // Once set, it indicates that the GC has started a goroutine leak detection run; + // it is set during gcStart and unset during gcMarkTermination; + // + // Protected by STW. + enabled bool + // Once set, it indicates that the GC has performed goroutine leak detection during + // the current GC cycle; it is set during gcMarkDone, right after goroutine leak detection, + // and unset during gcMarkTermination; + // + // Protected by STW. + done bool + // The number of leaked goroutines during the last leak detection GC cycle. + // + // Write-protected by STW in findGoroutineLeaks. + count int + } // Base indexes of each root type. Set by gcPrepareMarkRoots. baseData, baseBSS, baseSpans, baseStacks, baseEnd uint32 - // stackRoots is a snapshot of all of the Gs that existed - // before the beginning of concurrent marking. The backing - // store of this must not be modified because it might be - // shared with allgs. + // stackRoots is a snapshot of all of the Gs that existed before the + // beginning of concurrent marking. During goroutine leak detection, stackRoots + // is partitioned into two sets; to the left of nMaybeRunnableStackRoots are stackRoots + // of running / runnable goroutines and to the right of nMaybeRunnableStackRoots are + // stackRoots of unmarked / not runnable goroutines + // The stackRoots array is re-partitioned after each marking phase iteration. stackRoots []*g // Each type of GC state transition is protected by a lock. @@ -562,6 +589,55 @@ func GC() { releasem(mp) } +// goroutineLeakGC runs a GC cycle that performs goroutine leak detection. +// +//go:linkname goroutineLeakGC runtime/pprof.runtime_goroutineLeakGC +func goroutineLeakGC() { + // Set the pending flag to true, instructing the next GC cycle to + // perform goroutine leak detection. + work.goroutineLeak.pending.Store(true) + + // Spin GC cycles until the pending flag is unset. + // This ensures that goroutineLeakGC waits for a GC cycle that + // actually performs goroutine leak detection. + // + // This is needed in case multiple concurrent calls to GC + // are simultaneously fired by the system, wherein some + // of them are dropped. + // + // In the vast majority of cases, only one loop iteration is needed; + // however, multiple concurrent calls to goroutineLeakGC could lead to + // the execution of additional GC cycles. + // + // Examples: + // + // pending? | G1 | G2 + // ---------|-------------------------|----------------------- + // - | goroutineLeakGC() | goroutineLeakGC() + // - | pending.Store(true) | . + // X | for pending.Load() | . + // X | GC() | . + // X | > gcStart() | . + // X | pending.Store(false) | . + // ... + // - | > gcMarkDone() | . + // - | . | pending.Store(true) + // ... + // X | > gcMarkTermination() | . + // X | ... + // X | < GC returns | . + // X | for pending.Load | . + // X | GC() | . + // X | . | for pending.Load() + // X | . | GC() + // ... + // The first to pick up the pending flag will start a + // leak detection cycle. + for work.goroutineLeak.pending.Load() { + GC() + } +} + // gcWaitOnMark blocks until GC finishes the Nth mark phase. If GC has // already completed this mark phase, it returns immediately. func gcWaitOnMark(n uint32) { @@ -785,6 +861,15 @@ func gcStart(trigger gcTrigger) { schedEnableUser(false) } + // If goroutine leak detection is pending, enable it for this GC cycle. + if work.goroutineLeak.pending.Load() { + work.goroutineLeak.enabled = true + work.goroutineLeak.pending.Store(false) + // Set all sync objects of blocked goroutines as untraceable + // by the GC. Only set as traceable at the end of the GC cycle. + setSyncObjectsUntraceable() + } + // Enter concurrent mark phase and enable // write barriers. // @@ -995,8 +1080,20 @@ top: } } }) - if restart { - gcDebugMarkDone.restartedDueTo27993 = true + + // Check whether we need to resume the marking phase because of issue #27993 + // or because of goroutine leak detection. + if restart || (work.goroutineLeak.enabled && !work.goroutineLeak.done) { + if restart { + // Restart because of issue #27993. + gcDebugMarkDone.restartedDueTo27993 = true + } else { + // Marking has reached a fixed-point. Attempt to detect goroutine leaks. + // + // If the returned value is true, then detection already concluded for this cycle. + // Otherwise, more runnable goroutines were discovered, requiring additional mark work. + work.goroutineLeak.done = findGoroutineLeaks() + } getg().m.preemptoff = "" systemstack(func() { @@ -1047,6 +1144,172 @@ top: gcMarkTermination(stw) } +// isMaybeRunnable checks whether a goroutine may still be semantically runnable. +// For goroutines which are semantically runnable, this will eventually return true +// as the GC marking phase progresses. It returns false for leaked goroutines, or for +// goroutines which are not yet computed as possibly runnable by the GC. +func (gp *g) isMaybeRunnable() bool { + // Check whether the goroutine is actually in a waiting state first. + if readgstatus(gp) != _Gwaiting { + // If the goroutine is not waiting, then clearly it is maybe runnable. + return true + } + + switch gp.waitreason { + case waitReasonSelectNoCases, + waitReasonChanSendNilChan, + waitReasonChanReceiveNilChan: + // Select with no cases or communicating on nil channels + // make goroutines unrunnable by definition. + return false + case waitReasonChanReceive, + waitReasonSelect, + waitReasonChanSend: + // Cycle all through all *sudog to check whether + // the goroutine is waiting on a marked channel. + for sg := gp.waiting; sg != nil; sg = sg.waitlink { + if isMarkedOrNotInHeap(unsafe.Pointer(sg.c.get())) { + return true + } + } + return false + case waitReasonSyncCondWait, + waitReasonSyncWaitGroupWait, + waitReasonSyncMutexLock, + waitReasonSyncRWMutexLock, + waitReasonSyncRWMutexRLock: + // If waiting on mutexes, wait groups, or condition variables, + // check if the synchronization primitive attached to the sudog is marked. + if gp.waiting != nil { + return isMarkedOrNotInHeap(gp.waiting.elem.get()) + } + } + return true +} + +// findMaybeRunnableGoroutines checks to see if more blocked but maybe-runnable goroutines exist. +// If so, it adds them into root set and increments work.markrootJobs accordingly. +// Returns true if we need to run another phase of markroots; returns false otherwise. +func findMaybeRunnableGoroutines() (moreWork bool) { + oldRootJobs := work.markrootJobs.Load() + + // To begin with we have a set of unchecked stackRoots between + // vIndex and ivIndex. During the loop, anything < vIndex should be + // valid stackRoots and anything >= ivIndex should be invalid stackRoots. + // The loop terminates when the two indices meet. + var vIndex, ivIndex int = work.nMaybeRunnableStackRoots, work.nStackRoots + // Reorder goroutine list + for vIndex < ivIndex { + if work.stackRoots[vIndex].isMaybeRunnable() { + vIndex = vIndex + 1 + continue + } + for ivIndex = ivIndex - 1; ivIndex != vIndex; ivIndex = ivIndex - 1 { + if gp := work.stackRoots[ivIndex]; gp.isMaybeRunnable() { + work.stackRoots[ivIndex] = work.stackRoots[vIndex] + work.stackRoots[vIndex] = gp + vIndex = vIndex + 1 + break + } + } + } + + newRootJobs := work.baseStacks + uint32(vIndex) + if newRootJobs > oldRootJobs { + work.nMaybeRunnableStackRoots = vIndex + work.markrootJobs.Store(newRootJobs) + } + return newRootJobs > oldRootJobs +} + +// setSyncObjectsUntraceable scans allgs and sets the elem and c fields of all sudogs to +// an untrackable pointer. This prevents the GC from marking these objects as live in memory +// by following these pointers when runnning deadlock detection. +func setSyncObjectsUntraceable() { + assertWorldStopped() + + forEachGRace(func(gp *g) { + // Set as untraceable all synchronization objects of goroutines + // blocked at concurrency operations that could leak. + switch { + case gp.waitreason.isSyncWait(): + // Synchronization primitives are reachable from the *sudog via + // via the elem field. + for sg := gp.waiting; sg != nil; sg = sg.waitlink { + sg.elem.setUntraceable() + } + case gp.waitreason.isChanWait(): + // Channels and select statements are reachable from the *sudog via the c field. + for sg := gp.waiting; sg != nil; sg = sg.waitlink { + sg.c.setUntraceable() + } + } + }) +} + +// gcRestoreSyncObjects restores the elem and c fields of all sudogs to their original values. +// Should be invoked after the goroutine leak detection phase. +func gcRestoreSyncObjects() { + assertWorldStopped() + + forEachGRace(func(gp *g) { + for sg := gp.waiting; sg != nil; sg = sg.waitlink { + sg.elem.setTraceable() + sg.c.setTraceable() + } + }) +} + +// findGoroutineLeaks scans the remaining stackRoots and marks any which are +// blocked over exclusively unreachable concurrency primitives as leaked (deadlocked). +// Returns true if the goroutine leak check was performed (or unnecessary). +// Returns false if the GC cycle has not yet computed all maybe-runnable goroutines. +func findGoroutineLeaks() bool { + assertWorldStopped() + + // Report goroutine leaks and mark them unreachable, and resume marking + // we still need to mark these unreachable *g structs as they + // get reused, but their stack won't get scanned + if work.nMaybeRunnableStackRoots == work.nStackRoots { + // nMaybeRunnableStackRoots == nStackRoots means that all goroutines are marked. + return true + } + + // Check whether any more maybe-runnable goroutines can be found by the GC. + if findMaybeRunnableGoroutines() { + // We found more work, so we need to resume the marking phase. + return false + } + + // For the remaining goroutines, mark them as unreachable and leaked. + work.goroutineLeak.count = work.nStackRoots - work.nMaybeRunnableStackRoots + + for i := work.nMaybeRunnableStackRoots; i < work.nStackRoots; i++ { + gp := work.stackRoots[i] + casgstatus(gp, _Gwaiting, _Gleaked) + + // Add the primitives causing the goroutine leaks + // to the GC work queue, to ensure they are marked. + // + // NOTE(vsaioc): these primitives should also be reachable + // from the goroutine's stack, but let's play it safe. + switch { + case gp.waitreason.isChanWait(): + for sg := gp.waiting; sg != nil; sg = sg.waitlink { + shade(sg.c.uintptr()) + } + case gp.waitreason.isSyncWait(): + for sg := gp.waiting; sg != nil; sg = sg.waitlink { + shade(sg.elem.uintptr()) + } + } + } + // Put the remaining roots as ready for marking and drain them. + work.markrootJobs.Add(int32(work.nStackRoots - work.nMaybeRunnableStackRoots)) + work.nMaybeRunnableStackRoots = work.nStackRoots + return true +} + // World must be stopped and mark assists and background workers must be // disabled. func gcMarkTermination(stw worldStop) { @@ -1199,7 +1462,18 @@ func gcMarkTermination(stw worldStop) { throw("non-concurrent sweep failed to drain all sweep queues") } + if work.goroutineLeak.enabled { + // Restore the elem and c fields of all sudogs to their original values. + gcRestoreSyncObjects() + } + + var goroutineLeakDone bool systemstack(func() { + // Pull the GC out of goroutine leak detection mode. + work.goroutineLeak.enabled = false + goroutineLeakDone = work.goroutineLeak.done + work.goroutineLeak.done = false + // The memstats updated above must be updated with the world // stopped to ensure consistency of some values, such as // sched.idleTime and sched.totaltime. memstats also include @@ -1273,7 +1547,11 @@ func gcMarkTermination(stw worldStop) { printlock() print("gc ", memstats.numgc, " @", string(itoaDiv(sbuf[:], uint64(work.tSweepTerm-runtimeInitTime)/1e6, 3)), "s ", - util, "%: ") + util, "%") + if goroutineLeakDone { + print(" (checking for goroutine leaks)") + } + print(": ") prev := work.tSweepTerm for i, ns := range []int64{work.tMark, work.tMarkTerm, work.tEnd} { if i != 0 { @@ -1647,8 +1925,8 @@ func gcMark(startTime int64) { work.tstart = startTime // Check that there's no marking work remaining. - if work.full != 0 || work.markrootNext < work.markrootJobs { - print("runtime: full=", hex(work.full), " next=", work.markrootNext, " jobs=", work.markrootJobs, " nDataRoots=", work.nDataRoots, " nBSSRoots=", work.nBSSRoots, " nSpanRoots=", work.nSpanRoots, " nStackRoots=", work.nStackRoots, "\n") + if next, jobs := work.markrootNext.Load(), work.markrootJobs.Load(); work.full != 0 || next < jobs { + print("runtime: full=", hex(work.full), " next=", next, " jobs=", jobs, " nDataRoots=", work.nDataRoots, " nBSSRoots=", work.nBSSRoots, " nSpanRoots=", work.nSpanRoots, " nStackRoots=", work.nStackRoots, "\n") panic("non-empty mark queue after concurrent mark") } diff --git a/src/runtime/mgcmark.go b/src/runtime/mgcmark.go index bb5fcabab37db8..ba3824f00dc9cb 100644 --- a/src/runtime/mgcmark.go +++ b/src/runtime/mgcmark.go @@ -53,6 +53,55 @@ const ( pagesPerSpanRoot = min(512, pagesPerArena) ) +// internalBlocked returns true if the goroutine is blocked due to an +// internal (non-leaking) waitReason, e.g. waiting for the netpoller or garbage collector. +// Such goroutines are never leak detection candidates according to the GC. +// +//go:nosplit +func (gp *g) internalBlocked() bool { + reason := gp.waitreason + return reason < waitReasonChanReceiveNilChan || waitReasonSyncWaitGroupWait < reason +} + +// allGsSnapshotSortedForGC takes a snapshot of allgs and returns a sorted +// array of Gs. The array is sorted by the G's status, with running Gs +// first, followed by blocked Gs. The returned index indicates the cutoff +// between runnable and blocked Gs. +// +// The world must be stopped or allglock must be held. +func allGsSnapshotSortedForGC() ([]*g, int) { + assertWorldStoppedOrLockHeld(&allglock) + + // Reset the status of leaked goroutines in order to improve + // the precision of goroutine leak detection. + for _, gp := range allgs { + gp.atomicstatus.CompareAndSwap(_Gleaked, _Gwaiting) + } + + allgsSorted := make([]*g, len(allgs)) + + // Indices cutting off runnable and blocked Gs. + var currIndex, blockedIndex = 0, len(allgsSorted) - 1 + for _, gp := range allgs { + // not sure if we need atomic load because we are stopping the world, + // but do it just to be safe for now + if status := readgstatus(gp); status != _Gwaiting || gp.internalBlocked() { + allgsSorted[currIndex] = gp + currIndex++ + } else { + allgsSorted[blockedIndex] = gp + blockedIndex-- + } + } + + // Because the world is stopped or allglock is held, allgadd + // cannot happen concurrently with this. allgs grows + // monotonically and existing entries never change, so we can + // simply return a copy of the slice header. For added safety, + // we trim everything past len because that can still change. + return allgsSorted, blockedIndex + 1 +} + // gcPrepareMarkRoots queues root scanning jobs (stacks, globals, and // some miscellany) and initializes scanning-related state. // @@ -102,11 +151,20 @@ func gcPrepareMarkRoots() { // ignore them because they begin life without any roots, so // there's nothing to scan, and any roots they create during // the concurrent phase will be caught by the write barrier. - work.stackRoots = allGsSnapshot() + if work.goroutineLeak.enabled { + // goroutine leak finder GC --- only prepare runnable + // goroutines for marking. + work.stackRoots, work.nMaybeRunnableStackRoots = allGsSnapshotSortedForGC() + } else { + // regular GC --- scan every goroutine + work.stackRoots = allGsSnapshot() + work.nMaybeRunnableStackRoots = len(work.stackRoots) + } + work.nStackRoots = len(work.stackRoots) - work.markrootNext = 0 - work.markrootJobs = uint32(fixedRootCount + work.nDataRoots + work.nBSSRoots + work.nSpanRoots + work.nStackRoots) + work.markrootNext.Store(0) + work.markrootJobs.Store(uint32(fixedRootCount + work.nDataRoots + work.nBSSRoots + work.nSpanRoots + work.nMaybeRunnableStackRoots)) // Calculate base indexes of each root type work.baseData = uint32(fixedRootCount) @@ -119,8 +177,8 @@ func gcPrepareMarkRoots() { // gcMarkRootCheck checks that all roots have been scanned. It is // purely for debugging. func gcMarkRootCheck() { - if work.markrootNext < work.markrootJobs { - print(work.markrootNext, " of ", work.markrootJobs, " markroot jobs done\n") + if next, jobs := work.markrootNext.Load(), work.markrootJobs.Load(); next < jobs { + print(next, " of ", jobs, " markroot jobs done\n") throw("left over markroot jobs") } @@ -858,7 +916,7 @@ func scanstack(gp *g, gcw *gcWork) int64 { case _Grunning: print("runtime: gp=", gp, ", goid=", gp.goid, ", gp->atomicstatus=", readgstatus(gp), "\n") throw("scanstack: goroutine not stopped") - case _Grunnable, _Gsyscall, _Gwaiting: + case _Grunnable, _Gsyscall, _Gwaiting, _Gleaked: // ok } @@ -1126,6 +1184,28 @@ func gcDrainMarkWorkerFractional(gcw *gcWork) { gcDrain(gcw, gcDrainFractional|gcDrainUntilPreempt|gcDrainFlushBgCredit) } +// gcNextMarkRoot safely increments work.markrootNext and returns the +// index of the next root job. The returned boolean is true if the root job +// is valid, and false if there are no more root jobs to be claimed, +// i.e. work.markrootNext >= work.markrootJobs. +func gcNextMarkRoot() (uint32, bool) { + if !work.goroutineLeak.enabled { + // If not running goroutine leak detection, assume regular GC behavior. + job := work.markrootNext.Add(1) - 1 + return job, job < work.markrootJobs.Load() + } + + // Otherwise, use a CAS loop to increment markrootNext. + for next, jobs := work.markrootNext.Load(), work.markrootJobs.Load(); next < jobs; next = work.markrootNext.Load() { + // There is still work available at the moment. + if work.markrootNext.CompareAndSwap(next, next+1) { + // We manage to snatch a root job. Return the root index. + return next, true + } + } + return 0, false +} + // gcDrain scans roots and objects in work buffers, blackening grey // objects until it is unable to get more work. It may return before // GC is done; it's the caller's responsibility to balance work from @@ -1184,13 +1264,12 @@ func gcDrain(gcw *gcWork, flags gcDrainFlags) { } } - // Drain root marking jobs. - if work.markrootNext < work.markrootJobs { + if work.markrootNext.Load() < work.markrootJobs.Load() { // Stop if we're preemptible, if someone wants to STW, or if // someone is calling forEachP. for !(gp.preempt && (preemptible || sched.gcwaiting.Load() || pp.runSafePointFn != 0)) { - job := atomic.Xadd(&work.markrootNext, +1) - 1 - if job >= work.markrootJobs { + job, ok := gcNextMarkRoot() + if !ok { break } markroot(gcw, job, flushBgCredit) @@ -1342,9 +1421,9 @@ func gcDrainN(gcw *gcWork, scanWork int64) int64 { if b = gcw.tryGetObj(); b == 0 { if s = gcw.tryGetSpan(); s == 0 { // Try to do a root job. - if work.markrootNext < work.markrootJobs { - job := atomic.Xadd(&work.markrootNext, +1) - 1 - if job < work.markrootJobs { + if work.markrootNext.Load() < work.markrootJobs.Load() { + job, ok := gcNextMarkRoot() + if ok { workFlushed += markroot(gcw, job, false) continue } diff --git a/src/runtime/mgcmark_greenteagc.go b/src/runtime/mgcmark_greenteagc.go index 53fcd3d966ec3b..3975e1e76b501c 100644 --- a/src/runtime/mgcmark_greenteagc.go +++ b/src/runtime/mgcmark_greenteagc.go @@ -1143,7 +1143,7 @@ func gcMarkWorkAvailable() bool { if !work.full.empty() { return true // global work available } - if work.markrootNext < work.markrootJobs { + if work.markrootNext.Load() < work.markrootJobs.Load() { return true // root scan work available } if work.spanqMask.any() { diff --git a/src/runtime/mgcmark_nogreenteagc.go b/src/runtime/mgcmark_nogreenteagc.go index e4505032917210..9838887f7be008 100644 --- a/src/runtime/mgcmark_nogreenteagc.go +++ b/src/runtime/mgcmark_nogreenteagc.go @@ -124,7 +124,7 @@ func gcMarkWorkAvailable() bool { if !work.full.empty() { return true // global work available } - if work.markrootNext < work.markrootJobs { + if work.markrootNext.Load() < work.markrootJobs.Load() { return true // root scan work available } return false diff --git a/src/runtime/mprof.go b/src/runtime/mprof.go index 97b29076523d5d..0957e67b50fa2c 100644 --- a/src/runtime/mprof.go +++ b/src/runtime/mprof.go @@ -1259,6 +1259,20 @@ func goroutineProfileWithLabels(p []profilerecord.StackRecord, labels []unsafe.P return goroutineProfileWithLabelsConcurrent(p, labels) } +//go:linkname pprof_goroutineLeakProfileWithLabels +func pprof_goroutineLeakProfileWithLabels(p []profilerecord.StackRecord, labels []unsafe.Pointer) (n int, ok bool) { + return goroutineLeakProfileWithLabelsConcurrent(p, labels) +} + +// labels may be nil. If labels is non-nil, it must have the same length as p. +func goroutineLeakProfileWithLabels(p []profilerecord.StackRecord, labels []unsafe.Pointer) (n int, ok bool) { + if labels != nil && len(labels) != len(p) { + labels = nil + } + + return goroutineLeakProfileWithLabelsConcurrent(p, labels) +} + var goroutineProfile = struct { sema uint32 active bool @@ -1302,6 +1316,48 @@ func (p *goroutineProfileStateHolder) CompareAndSwap(old, new goroutineProfileSt return (*atomic.Uint32)(p).CompareAndSwap(uint32(old), uint32(new)) } +func goroutineLeakProfileWithLabelsConcurrent(p []profilerecord.StackRecord, labels []unsafe.Pointer) (n int, ok bool) { + if len(p) == 0 { + // An empty slice is obviously too small. Return a rough + // allocation estimate. + return work.goroutineLeak.count, false + } + + // Use the same semaphore as goroutineProfileWithLabelsConcurrent, + // because ultimately we still use goroutine profiles. + semacquire(&goroutineProfile.sema) + + // Unlike in goroutineProfileWithLabelsConcurrent, we don't need to + // save the current goroutine stack, because it is obviously not leaked. + + pcbuf := makeProfStack() // see saveg() for explanation + + // Prepare a profile large enough to store all leaked goroutines. + n = work.goroutineLeak.count + + if n > len(p) { + // There's not enough space in p to store the whole profile, so (per the + // contract of runtime.GoroutineProfile) we're not allowed to write to p + // at all and must return n, false. + semrelease(&goroutineProfile.sema) + return n, false + } + + // Visit each leaked goroutine and try to record its stack. + forEachGRace(func(gp1 *g) { + if readgstatus(gp1) == _Gleaked { + doRecordGoroutineProfile(gp1, pcbuf) + } + }) + + if raceenabled { + raceacquire(unsafe.Pointer(&labelSync)) + } + + semrelease(&goroutineProfile.sema) + return n, true +} + func goroutineProfileWithLabelsConcurrent(p []profilerecord.StackRecord, labels []unsafe.Pointer) (n int, ok bool) { if len(p) == 0 { // An empty slice is obviously too small. Return a rough diff --git a/src/runtime/pprof/pprof.go b/src/runtime/pprof/pprof.go index 55563009b3a2c1..b524e992b8b209 100644 --- a/src/runtime/pprof/pprof.go +++ b/src/runtime/pprof/pprof.go @@ -80,6 +80,7 @@ import ( "cmp" "fmt" "internal/abi" + "internal/goexperiment" "internal/profilerecord" "io" "runtime" @@ -105,12 +106,13 @@ import ( // // Each Profile has a unique name. A few profiles are predefined: // -// goroutine - stack traces of all current goroutines -// heap - a sampling of memory allocations of live objects -// allocs - a sampling of all past memory allocations -// threadcreate - stack traces that led to the creation of new OS threads -// block - stack traces that led to blocking on synchronization primitives -// mutex - stack traces of holders of contended mutexes +// goroutine - stack traces of all current goroutines +// goroutineleak - stack traces of all leaked goroutines +// allocs - a sampling of all past memory allocations +// heap - a sampling of memory allocations of live objects +// threadcreate - stack traces that led to the creation of new OS threads +// block - stack traces that led to blocking on synchronization primitives +// mutex - stack traces of holders of contended mutexes // // These predefined profiles maintain themselves and panic on an explicit // [Profile.Add] or [Profile.Remove] method call. @@ -169,6 +171,7 @@ import ( // holds a lock for 1s while 5 other goroutines are waiting for the entire // second to acquire the lock, its unlock call stack will report 5s of // contention. + type Profile struct { name string mu sync.Mutex @@ -189,6 +192,12 @@ var goroutineProfile = &Profile{ write: writeGoroutine, } +var goroutineLeakProfile = &Profile{ + name: "goroutineleak", + count: runtime_goroutineleakcount, + write: writeGoroutineLeak, +} + var threadcreateProfile = &Profile{ name: "threadcreate", count: countThreadCreate, @@ -231,6 +240,9 @@ func lockProfiles() { "block": blockProfile, "mutex": mutexProfile, } + if goexperiment.GoroutineLeakProfile { + profiles.m["goroutineleak"] = goroutineLeakProfile + } } } @@ -275,6 +287,7 @@ func Profiles() []*Profile { all := make([]*Profile, 0, len(profiles.m)) for _, p := range profiles.m { + all = append(all, p) } @@ -747,6 +760,23 @@ func writeGoroutine(w io.Writer, debug int) error { return writeRuntimeProfile(w, debug, "goroutine", pprof_goroutineProfileWithLabels) } +// writeGoroutineLeak first invokes a GC cycle that performs goroutine leak detection. +// It then writes the goroutine profile, filtering for leaked goroutines. +func writeGoroutineLeak(w io.Writer, debug int) error { + // Run the GC with leak detection first so that leaked goroutines + // may transition to the leaked state. + runtime_goroutineLeakGC() + + // If the debug flag is set sufficiently high, just defer to writing goroutine stacks + // like in a regular goroutine profile. Include non-leaked goroutines, too. + if debug >= 2 { + return writeGoroutineStacks(w) + } + + // Otherwise, write the goroutine leak profile. + return writeRuntimeProfile(w, debug, "goroutineleak", pprof_goroutineLeakProfileWithLabels) +} + func writeGoroutineStacks(w io.Writer) error { // We don't know how big the buffer needs to be to collect // all the goroutines. Start with 1 MB and try a few times, doubling each time. @@ -969,6 +999,9 @@ func writeProfileInternal(w io.Writer, debug int, name string, runtimeProfile fu //go:linkname pprof_goroutineProfileWithLabels runtime.pprof_goroutineProfileWithLabels func pprof_goroutineProfileWithLabels(p []profilerecord.StackRecord, labels []unsafe.Pointer) (n int, ok bool) +//go:linkname pprof_goroutineLeakProfileWithLabels runtime.pprof_goroutineLeakProfileWithLabels +func pprof_goroutineLeakProfileWithLabels(p []profilerecord.StackRecord, labels []unsafe.Pointer) (n int, ok bool) + //go:linkname pprof_cyclesPerSecond runtime/pprof.runtime_cyclesPerSecond func pprof_cyclesPerSecond() int64 diff --git a/src/runtime/pprof/runtime.go b/src/runtime/pprof/runtime.go index 8d37c7d3add146..690cab81ab5a5a 100644 --- a/src/runtime/pprof/runtime.go +++ b/src/runtime/pprof/runtime.go @@ -29,6 +29,12 @@ func runtime_setProfLabel(labels unsafe.Pointer) // runtime_getProfLabel is defined in runtime/proflabel.go. func runtime_getProfLabel() unsafe.Pointer +// runtime_goroutineleakcount is defined in runtime/proc.go. +func runtime_goroutineleakcount() int + +// runtime_goroutineLeakGC is defined in runtime/mgc.go. +func runtime_goroutineLeakGC() + // SetGoroutineLabels sets the current goroutine's labels to match ctx. // A new goroutine inherits the labels of the goroutine that created it. // This is a lower-level API than [Do], which should be used instead when possible. diff --git a/src/runtime/preempt.go b/src/runtime/preempt.go index 22727df74eead2..5367f66213804b 100644 --- a/src/runtime/preempt.go +++ b/src/runtime/preempt.go @@ -160,7 +160,7 @@ func suspendG(gp *g) suspendGState { s = _Gwaiting fallthrough - case _Grunnable, _Gsyscall, _Gwaiting: + case _Grunnable, _Gsyscall, _Gwaiting, _Gleaked: // Claim goroutine by setting scan bit. // This may race with execution or readying of gp. // The scan bit keeps it from transition state. @@ -269,6 +269,7 @@ func resumeG(state suspendGState) { case _Grunnable | _Gscan, _Gwaiting | _Gscan, + _Gleaked | _Gscan, _Gsyscall | _Gscan: casfrom_Gscanstatus(gp, s, s&^_Gscan) } diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 4b1ab1af6a5075..e5686705293e8a 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -517,7 +517,7 @@ func acquireSudog() *sudog { s := pp.sudogcache[n-1] pp.sudogcache[n-1] = nil pp.sudogcache = pp.sudogcache[:n-1] - if s.elem != nil { + if s.elem.get() != nil { throw("acquireSudog: found s.elem != nil in cache") } releasem(mp) @@ -526,7 +526,7 @@ func acquireSudog() *sudog { //go:nosplit func releaseSudog(s *sudog) { - if s.elem != nil { + if s.elem.get() != nil { throw("runtime: sudog with non-nil elem") } if s.isSelect { @@ -541,7 +541,7 @@ func releaseSudog(s *sudog) { if s.waitlink != nil { throw("runtime: sudog with non-nil waitlink") } - if s.c != nil { + if s.c.get() != nil { throw("runtime: sudog with non-nil c") } gp := getg() @@ -1222,6 +1222,7 @@ func casfrom_Gscanstatus(gp *g, oldval, newval uint32) { _Gscanwaiting, _Gscanrunning, _Gscansyscall, + _Gscanleaked, _Gscanpreempted: if newval == oldval&^_Gscan { success = gp.atomicstatus.CompareAndSwap(oldval, newval) @@ -1242,6 +1243,7 @@ func castogscanstatus(gp *g, oldval, newval uint32) bool { case _Grunnable, _Grunning, _Gwaiting, + _Gleaked, _Gsyscall: if newval == oldval|_Gscan { r := gp.atomicstatus.CompareAndSwap(oldval, newval) @@ -5565,6 +5567,14 @@ func gcount(includeSys bool) int32 { return n } +// goroutineleakcount returns the number of leaked goroutines last reported by +// the runtime. +// +//go:linkname goroutineleakcount runtime/pprof.runtime_goroutineleakcount +func goroutineleakcount() int { + return work.goroutineLeak.count +} + func mcount() int32 { return int32(sched.mnext - sched.nmfreed) } diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go index 042c3137cd03df..6016c6fde054fb 100644 --- a/src/runtime/runtime2.go +++ b/src/runtime/runtime2.go @@ -87,6 +87,9 @@ const ( // ready()ing this G. _Gpreempted // 9 + // _Gleaked represents a leaked goroutine caught by the GC. + _Gleaked // 10 + // _Gscan combined with one of the above states other than // _Grunning indicates that GC is scanning the stack. The // goroutine is not executing user code and the stack is owned @@ -104,6 +107,7 @@ const ( _Gscansyscall = _Gscan + _Gsyscall // 0x1003 _Gscanwaiting = _Gscan + _Gwaiting // 0x1004 _Gscanpreempted = _Gscan + _Gpreempted // 0x1009 + _Gscanleaked = _Gscan + _Gleaked // 0x100a ) const ( @@ -315,6 +319,78 @@ type gobuf struct { bp uintptr // for framepointer-enabled architectures } +// maybeTraceablePtr is a special pointer that is conditionally trackable +// by the GC. It consists of an address as a uintptr (vu) and a pointer +// to a data element (vp). +// +// maybeTraceablePtr values can be in one of three states: +// 1. Unset: vu == 0 && vp == nil +// 2. Untracked: vu != 0 && vp == nil +// 3. Tracked: vu != 0 && vp != nil +// +// Do not set fields manually. Use methods instead. +// Extend this type with additional methods if needed. +type maybeTraceablePtr struct { + vp unsafe.Pointer // For liveness only. + vu uintptr // Source of truth. +} + +// untrack unsets the pointer but preserves the address. +// This is used to hide the pointer from the GC. +// +//go:nosplit +func (p *maybeTraceablePtr) setUntraceable() { + p.vp = nil +} + +// setTraceable resets the pointer to the stored address. +// This is used to make the pointer visible to the GC. +// +//go:nosplit +func (p *maybeTraceablePtr) setTraceable() { + p.vp = unsafe.Pointer(p.vu) +} + +// set sets the pointer to the data element and updates the address. +// +//go:nosplit +func (p *maybeTraceablePtr) set(v unsafe.Pointer) { + p.vp = v + p.vu = uintptr(v) +} + +// get retrieves the pointer to the data element. +// +//go:nosplit +func (p *maybeTraceablePtr) get() unsafe.Pointer { + return unsafe.Pointer(p.vu) +} + +// uintptr returns the uintptr address of the pointer. +// +//go:nosplit +func (p *maybeTraceablePtr) uintptr() uintptr { + return p.vu +} + +// maybeTraceableChan extends conditionally trackable pointers (maybeTraceablePtr) +// to track hchan pointers. +// +// Do not set fields manually. Use methods instead. +type maybeTraceableChan struct { + maybeTraceablePtr +} + +//go:nosplit +func (p *maybeTraceableChan) set(c *hchan) { + p.maybeTraceablePtr.set(unsafe.Pointer(c)) +} + +//go:nosplit +func (p *maybeTraceableChan) get() *hchan { + return (*hchan)(p.maybeTraceablePtr.get()) +} + // sudog (pseudo-g) represents a g in a wait list, such as for sending/receiving // on a channel. // @@ -334,7 +410,8 @@ type sudog struct { next *sudog prev *sudog - elem unsafe.Pointer // data element (may point to stack) + + elem maybeTraceablePtr // data element (may point to stack) // The following fields are never accessed concurrently. // For channels, waitlink is only accessed by g. @@ -362,10 +439,10 @@ type sudog struct { // in the second entry in the list.) waiters uint16 - parent *sudog // semaRoot binary tree - waitlink *sudog // g.waiting list or semaRoot - waittail *sudog // semaRoot - c *hchan // channel + parent *sudog // semaRoot binary tree + waitlink *sudog // g.waiting list or semaRoot + waittail *sudog // semaRoot + c maybeTraceableChan // channel } type libcall struct { @@ -1072,24 +1149,24 @@ const ( waitReasonZero waitReason = iota // "" waitReasonGCAssistMarking // "GC assist marking" waitReasonIOWait // "IO wait" - waitReasonChanReceiveNilChan // "chan receive (nil chan)" - waitReasonChanSendNilChan // "chan send (nil chan)" waitReasonDumpingHeap // "dumping heap" waitReasonGarbageCollection // "garbage collection" waitReasonGarbageCollectionScan // "garbage collection scan" waitReasonPanicWait // "panicwait" - waitReasonSelect // "select" - waitReasonSelectNoCases // "select (no cases)" waitReasonGCAssistWait // "GC assist wait" waitReasonGCSweepWait // "GC sweep wait" waitReasonGCScavengeWait // "GC scavenge wait" - waitReasonChanReceive // "chan receive" - waitReasonChanSend // "chan send" waitReasonFinalizerWait // "finalizer wait" waitReasonForceGCIdle // "force gc (idle)" waitReasonUpdateGOMAXPROCSIdle // "GOMAXPROCS updater (idle)" waitReasonSemacquire // "semacquire" waitReasonSleep // "sleep" + waitReasonChanReceiveNilChan // "chan receive (nil chan)" + waitReasonChanSendNilChan // "chan send (nil chan)" + waitReasonSelectNoCases // "select (no cases)" + waitReasonSelect // "select" + waitReasonChanReceive // "chan receive" + waitReasonChanSend // "chan send" waitReasonSyncCondWait // "sync.Cond.Wait" waitReasonSyncMutexLock // "sync.Mutex.Lock" waitReasonSyncRWMutexRLock // "sync.RWMutex.RLock" @@ -1175,12 +1252,34 @@ func (w waitReason) String() string { return waitReasonStrings[w] } +// isMutexWait returns true if the goroutine is blocked because of +// sync.Mutex.Lock or sync.RWMutex.[R]Lock. +// +//go:nosplit func (w waitReason) isMutexWait() bool { return w == waitReasonSyncMutexLock || w == waitReasonSyncRWMutexRLock || w == waitReasonSyncRWMutexLock } +// isSyncWait returns true if the goroutine is blocked because of +// sync library primitive operations. +// +//go:nosplit +func (w waitReason) isSyncWait() bool { + return waitReasonSyncCondWait <= w && w <= waitReasonSyncWaitGroupWait +} + +// isChanWait is true if the goroutine is blocked because of non-nil +// channel operations or a select statement with at least one case. +// +//go:nosplit +func (w waitReason) isChanWait() bool { + return w == waitReasonSelect || + w == waitReasonChanReceive || + w == waitReasonChanSend +} + func (w waitReason) isWaitingForSuspendG() bool { return isWaitingForSuspendG[w] } diff --git a/src/runtime/select.go b/src/runtime/select.go index 113dc8ad19e984..553f6960eb1286 100644 --- a/src/runtime/select.go +++ b/src/runtime/select.go @@ -83,7 +83,7 @@ func selparkcommit(gp *g, _ unsafe.Pointer) bool { // channels in lock order. var lastc *hchan for sg := gp.waiting; sg != nil; sg = sg.waitlink { - if sg.c != lastc && lastc != nil { + if sg.c.get() != lastc && lastc != nil { // As soon as we unlock the channel, fields in // any sudog with that channel may change, // including c and waitlink. Since multiple @@ -92,7 +92,7 @@ func selparkcommit(gp *g, _ unsafe.Pointer) bool { // of a channel. unlock(&lastc.lock) } - lastc = sg.c + lastc = sg.c.get() } if lastc != nil { unlock(&lastc.lock) @@ -320,12 +320,12 @@ func selectgo(cas0 *scase, order0 *uint16, pc0 *uintptr, nsends, nrecvs int, blo sg.isSelect = true // No stack splits between assigning elem and enqueuing // sg on gp.waiting where copystack can find it. - sg.elem = cas.elem + sg.elem.set(cas.elem) sg.releasetime = 0 if t0 != 0 { sg.releasetime = -1 } - sg.c = c + sg.c.set(c) // Construct waiting list in lock order. *nextp = sg nextp = &sg.waitlink @@ -368,8 +368,8 @@ func selectgo(cas0 *scase, order0 *uint16, pc0 *uintptr, nsends, nrecvs int, blo // Clear all elem before unlinking from gp.waiting. for sg1 := gp.waiting; sg1 != nil; sg1 = sg1.waitlink { sg1.isSelect = false - sg1.elem = nil - sg1.c = nil + sg1.elem.set(nil) + sg1.c.set(nil) } gp.waiting = nil diff --git a/src/runtime/sema.go b/src/runtime/sema.go index 6af49b1b0c42d9..0fe0f2a2c20739 100644 --- a/src/runtime/sema.go +++ b/src/runtime/sema.go @@ -303,7 +303,10 @@ func cansemacquire(addr *uint32) bool { // queue adds s to the blocked goroutines in semaRoot. func (root *semaRoot) queue(addr *uint32, s *sudog, lifo bool) { s.g = getg() - s.elem = unsafe.Pointer(addr) + s.elem.set(unsafe.Pointer(addr)) + // Storing this pointer so that we can trace the semaphore address + // from the blocked goroutine when checking for goroutine leaks. + s.g.waiting = s s.next = nil s.prev = nil s.waiters = 0 @@ -311,7 +314,7 @@ func (root *semaRoot) queue(addr *uint32, s *sudog, lifo bool) { var last *sudog pt := &root.treap for t := *pt; t != nil; t = *pt { - if t.elem == unsafe.Pointer(addr) { + if uintptr(unsafe.Pointer(addr)) == t.elem.uintptr() { // Already have addr in list. if lifo { // Substitute s in t's place in treap. @@ -357,7 +360,7 @@ func (root *semaRoot) queue(addr *uint32, s *sudog, lifo bool) { return } last = t - if uintptr(unsafe.Pointer(addr)) < uintptr(t.elem) { + if uintptr(unsafe.Pointer(addr)) < t.elem.uintptr() { pt = &t.prev } else { pt = &t.next @@ -402,11 +405,13 @@ func (root *semaRoot) queue(addr *uint32, s *sudog, lifo bool) { func (root *semaRoot) dequeue(addr *uint32) (found *sudog, now, tailtime int64) { ps := &root.treap s := *ps + for ; s != nil; s = *ps { - if s.elem == unsafe.Pointer(addr) { + if uintptr(unsafe.Pointer(addr)) == s.elem.uintptr() { goto Found } - if uintptr(unsafe.Pointer(addr)) < uintptr(s.elem) { + + if uintptr(unsafe.Pointer(addr)) < s.elem.uintptr() { ps = &s.prev } else { ps = &s.next @@ -470,8 +475,10 @@ Found: } tailtime = s.acquiretime } + // Goroutine is no longer blocked. Clear the waiting pointer. + s.g.waiting = nil s.parent = nil - s.elem = nil + s.elem.set(nil) s.next = nil s.prev = nil s.ticket = 0 @@ -590,6 +597,10 @@ func notifyListWait(l *notifyList, t uint32) { // Enqueue itself. s := acquireSudog() s.g = getg() + // Storing this pointer so that we can trace the condvar address + // from the blocked goroutine when checking for goroutine leaks. + s.elem.set(unsafe.Pointer(l)) + s.g.waiting = s s.ticket = t s.releasetime = 0 t0 := int64(0) @@ -607,6 +618,10 @@ func notifyListWait(l *notifyList, t uint32) { if t0 != 0 { blockevent(s.releasetime-t0, 2) } + // Goroutine is no longer blocked. Clear up its waiting pointer, + // and clean up the sudog before releasing it. + s.g.waiting = nil + s.elem.set(nil) releaseSudog(s) } diff --git a/src/runtime/sizeof_test.go b/src/runtime/sizeof_test.go index de859866a5adb2..5888177f0ea7a1 100644 --- a/src/runtime/sizeof_test.go +++ b/src/runtime/sizeof_test.go @@ -22,7 +22,7 @@ func TestSizeof(t *testing.T) { _64bit uintptr // size on 64bit platforms }{ {runtime.G{}, 280 + xreg, 440 + xreg}, // g, but exported for testing - {runtime.Sudog{}, 56, 88}, // sudog, but exported for testing + {runtime.Sudog{}, 64, 104}, // sudog, but exported for testing } if xreg > runtime.PtrSize { diff --git a/src/runtime/stack.go b/src/runtime/stack.go index d809820b076dfd..55e97e77afa957 100644 --- a/src/runtime/stack.go +++ b/src/runtime/stack.go @@ -821,7 +821,8 @@ func adjustsudogs(gp *g, adjinfo *adjustinfo) { // the data elements pointed to by a SudoG structure // might be in the stack. for s := gp.waiting; s != nil; s = s.waitlink { - adjustpointer(adjinfo, unsafe.Pointer(&s.elem)) + adjustpointer(adjinfo, unsafe.Pointer(&s.elem.vu)) + adjustpointer(adjinfo, unsafe.Pointer(&s.elem.vp)) } } @@ -834,7 +835,7 @@ func fillstack(stk stack, b byte) { func findsghi(gp *g, stk stack) uintptr { var sghi uintptr for sg := gp.waiting; sg != nil; sg = sg.waitlink { - p := uintptr(sg.elem) + uintptr(sg.c.elemsize) + p := sg.elem.uintptr() + uintptr(sg.c.get().elemsize) if stk.lo <= p && p < stk.hi && p > sghi { sghi = p } @@ -853,7 +854,7 @@ func syncadjustsudogs(gp *g, used uintptr, adjinfo *adjustinfo) uintptr { // Lock channels to prevent concurrent send/receive. var lastc *hchan for sg := gp.waiting; sg != nil; sg = sg.waitlink { - if sg.c != lastc { + if sg.c.get() != lastc { // There is a ranking cycle here between gscan bit and // hchan locks. Normally, we only allow acquiring hchan // locks and then getting a gscan bit. In this case, we @@ -863,9 +864,9 @@ func syncadjustsudogs(gp *g, used uintptr, adjinfo *adjustinfo) uintptr { // suspended. So, we get a special hchan lock rank here // that is lower than gscan, but doesn't allow acquiring // any other locks other than hchan. - lockWithRank(&sg.c.lock, lockRankHchanLeaf) + lockWithRank(&sg.c.get().lock, lockRankHchanLeaf) } - lastc = sg.c + lastc = sg.c.get() } // Adjust sudogs. @@ -885,10 +886,10 @@ func syncadjustsudogs(gp *g, used uintptr, adjinfo *adjustinfo) uintptr { // Unlock channels. lastc = nil for sg := gp.waiting; sg != nil; sg = sg.waitlink { - if sg.c != lastc { - unlock(&sg.c.lock) + if sg.c.get() != lastc { + unlock(&sg.c.get().lock) } - lastc = sg.c + lastc = sg.c.get() } return sgsize diff --git a/src/runtime/testdata/testgoroutineleakprofile/commonpatterns.go b/src/runtime/testdata/testgoroutineleakprofile/commonpatterns.go new file mode 100644 index 00000000000000..353e48ee7034f7 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/commonpatterns.go @@ -0,0 +1,277 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import ( + "context" + "fmt" + "os" + "runtime" + "runtime/pprof" + "time" +) + +// Common goroutine leak patterns. Extracted from: +// "Unveiling and Vanquishing Goroutine Leaks in Enterprise Microservices: A Dynamic Analysis Approach" +// doi:10.1109/CGO57630.2024.10444835 +// +// Tests in this file are not flaky iff. the test is run with GOMAXPROCS=1. +// The main goroutine forcefully yields via `runtime.Gosched()` before +// running the profiler. This moves them to the back of the run queue, +// allowing the leaky goroutines to be scheduled beforehand and get stuck. + +func init() { + register("NoCloseRange", NoCloseRange) + register("MethodContractViolation", MethodContractViolation) + register("DoubleSend", DoubleSend) + register("EarlyReturn", EarlyReturn) + register("NCastLeak", NCastLeak) + register("Timeout", Timeout) +} + +// Incoming list of items and the number of workers. +func noCloseRange(list []any, workers int) { + ch := make(chan any) + + // Create each worker + for i := 0; i < workers; i++ { + go func() { + + // Each worker waits for an item and processes it. + for item := range ch { + // Process each item + _ = item + } + }() + } + + // Send each item to one of the workers. + for _, item := range list { + // Sending can leak if workers == 0 or if one of the workers panics + ch <- item + } + // The channel is never closed, so workers leak once there are no more + // items left to process. +} + +func NoCloseRange() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + go noCloseRange([]any{1, 2, 3}, 0) + go noCloseRange([]any{1, 2, 3}, 3) +} + +// A worker processes items pushed to `ch` one by one in the background. +// When the worker is no longer needed, it must be closed with `Stop`. +// +// Specifications: +// +// A worker may be started any number of times, but must be stopped only once. +// Stopping a worker multiple times will lead to a close panic. +// Any worker that is started must eventually be stopped. +// Failing to stop a worker results in a goroutine leak +type worker struct { + ch chan any + done chan any +} + +// Start spawns a background goroutine that extracts items pushed to the queue. +func (w worker) Start() { + go func() { + + for { + select { + case <-w.ch: // Normal workflow + case <-w.done: + return // Shut down + } + } + }() +} + +func (w worker) Stop() { + // Allows goroutine created by Start to terminate + close(w.done) +} + +func (w worker) AddToQueue(item any) { + w.ch <- item +} + +// worker limited in scope by workerLifecycle +func workerLifecycle(items []any) { + // Create a new worker + w := worker{ + ch: make(chan any), + done: make(chan any), + } + // Start worker + w.Start() + + // Operate on worker + for _, item := range items { + w.AddToQueue(item) + } + + runtime.Gosched() + // Exits without calling ’Stop’. Goroutine created by `Start` eventually leaks. +} + +func MethodContractViolation() { + prof := pprof.Lookup("goroutineleak") + defer func() { + runtime.Gosched() + prof.WriteTo(os.Stdout, 2) + }() + + workerLifecycle(make([]any, 10)) + runtime.Gosched() +} + +// doubleSend incoming channel must send a message (incoming error simulates an error generated internally). +func doubleSend(ch chan any, err error) { + if err != nil { + // In case of an error, send nil. + ch <- nil + // Return is missing here. + } + // Otherwise, continue with normal behaviour + // This send is still executed in the error case, which may lead to a goroutine leak. + ch <- struct{}{} +} + +func DoubleSend() { + prof := pprof.Lookup("goroutineleak") + ch := make(chan any) + defer func() { + runtime.Gosched() + prof.WriteTo(os.Stdout, 2) + }() + + go func() { + doubleSend(ch, nil) + }() + <-ch + + go func() { + doubleSend(ch, fmt.Errorf("error")) + }() + <-ch + + ch1 := make(chan any, 1) + go func() { + doubleSend(ch1, fmt.Errorf("error")) + }() + <-ch1 +} + +// earlyReturn demonstrates a common pattern of goroutine leaks. +// A return statement interrupts the evaluation of the parent goroutine before it can consume a message. +// Incoming error simulates an error produced internally. +func earlyReturn(err error) { + // Create a synchronous channel + ch := make(chan any) + + go func() { + + // Send something to the channel. + // Leaks if the parent goroutine terminates early. + ch <- struct{}{} + }() + + if err != nil { + // Interrupt evaluation of parent early in case of error. + // Sender leaks. + return + } + + // Only receive if there is no error. + <-ch +} + +func EarlyReturn() { + prof := pprof.Lookup("goroutineleak") + defer func() { + runtime.Gosched() + prof.WriteTo(os.Stdout, 2) + }() + + go earlyReturn(fmt.Errorf("error")) +} + +// nCastLeak processes a number of items. First result to pass the post is retrieved from the channel queue. +func nCastLeak(items []any) { + // Channel is synchronous. + ch := make(chan any) + + // Iterate over every item + for range items { + go func() { + + // Process item and send result to channel + ch <- struct{}{} + // Channel is synchronous: only one sender will synchronise + }() + } + // Retrieve first result. All other senders block. + // Receiver blocks if there are no senders. + <-ch +} + +func NCastLeak() { + prof := pprof.Lookup("goroutineleak") + defer func() { + for i := 0; i < yieldCount; i++ { + // Yield enough times to allow all the leaky goroutines to + // reach the execution point. + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + go func() { + nCastLeak(nil) + }() + + go func() { + nCastLeak(make([]any, 5)) + }() +} + +// A context is provided to short-circuit evaluation, leading +// the sender goroutine to leak. +func timeout(ctx context.Context) { + ch := make(chan any) + + go func() { + ch <- struct{}{} + }() + + select { + case <-ch: // Receive message + // Sender is released + case <-ctx.Done(): // Context was cancelled or timed out + // Sender is leaked + } +} + +func Timeout() { + prof := pprof.Lookup("goroutineleak") + defer func() { + runtime.Gosched() + prof.WriteTo(os.Stdout, 2) + }() + + ctx, cancel := context.WithCancel(context.Background()) + cancel() + + for i := 0; i < 100; i++ { + go timeout(ctx) + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/LICENSE b/src/runtime/testdata/testgoroutineleakprofile/goker/LICENSE new file mode 100644 index 00000000000000..f4b4b8abc4b372 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/LICENSE @@ -0,0 +1,21 @@ +The MIT License (MIT) +Copyright © 2021 Institute of Computing Technology, University of New South Wales + + +Permission is hereby granted, free of charge, to any person obtaining +a copy of this software and associated documentation files (the “Software”), +to deal in the Software without restriction, including without limitation +the rights to use, copy, modify, merge, publish, distribute, sublicense, +and/or sell copies of the Software, and to permit persons to whom the +Software is furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included +in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS +OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL +THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING +FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. \ No newline at end of file diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/README.md b/src/runtime/testdata/testgoroutineleakprofile/goker/README.md new file mode 100644 index 00000000000000..88c50e1e480a08 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/README.md @@ -0,0 +1,1847 @@ +# GoKer + +The following examples are obtained from the publication +"GoBench: A Benchmark Suite of Real-World Go Concurrency Bugs" +(doi:10.1109/CGO51591.2021.9370317). + +**Authors** +Ting Yuan (yuanting@ict.ac.cn): + State Key Laboratory of Computer Architecture, Institute of Computing Technology, Chinese Academy of Sciences, + University of Chinese Academy of Sciences, Beijing, China; +Guangwei Li (liguangwei@ict.ac.cn): + State Key Laboratory of Computer Architecture, Institute of Computing Technology, Chinese Academy of Sciences, + University of Chinese Academy of Sciences, Beijing, China; +Jie Lu† (lujie@ict.ac.an): + State Key Laboratory of Computer Architecture, Institute of Computing Technology, Chinese Academy of Sciences; +Chen Liu (liuchen17z@ict.ac.cn): + State Key Laboratory of Computer Architecture, Institute of Computing Technology, Chinese Academy of Sciences, + University of Chinese Academy of Sciences, Beijing, China +Lian Li (lianli@ict.ac.cn): + State Key Laboratory of Computer Architecture, Institute of Computing Technology, Chinese Academy of Sciences, + University of Chinese Academy of Sciences, Beijing, China; +Jingling Xue (jingling@cse.unsw.edu.au): + University of New South Wales, School of Computer Science and Engineering, Sydney, Australia + +White paper: https://lujie.ac.cn/files/papers/GoBench.pdf + +The examples have been modified in order to run the goroutine leak +profiler. Buggy snippets are moved from within a unit test to separate +applications. Each is then independently executed, possibly as multiple +copies within the same application in order to exercise more interleavings. +Concurrently, the main program sets up a waiting period (typically 1ms), followed +by a goroutine leak profile request. Other modifications may involve injecting calls +to `runtime.Gosched()`, to more reliably exercise buggy interleavings, or reductions +in waiting periods when calling `time.Sleep`, in order to reduce overall testing time. + +The resulting goroutine leak profile is analyzed to ensure that no unexpected leaks occurred, +and that the expected leaks did occur. If the leak is flaky, the only purpose of the expected +leak list is to protect against unexpected leaks. + +The entries below document each of the corresponding leaks. + +## Cockroach/10214 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#10214]|[pull request]|[patch]| Resource | AB-BA leak | + +[cockroach#10214]:(cockroach10214_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/10214/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/10214 + +### Description + +This goroutine leak is caused by different order when acquiring +coalescedMu.Lock() and raftMu.Lock(). The fix is to refactor sendQueuedHeartbeats() +so that cockroachdb can unlock coalescedMu before locking raftMu. + +### Example execution + +```go +G1 G2 +------------------------------------------------------------------------------------ +s.sendQueuedHeartbeats() . +s.coalescedMu.Lock() [L1] . +s.sendQueuedHeartbeatsToNode() . +s.mu.replicas[0].reportUnreachable() . +s.mu.replicas[0].raftMu.Lock() [L2] . +. s.mu.replicas[0].tick() +. s.mu.replicas[0].raftMu.Lock() [L2] +. s.mu.replicas[0].tickRaftMuLocked() +. s.mu.replicas[0].mu.Lock() [L3] +. s.mu.replicas[0].maybeQuiesceLocked() +. s.mu.replicas[0].maybeCoalesceHeartbeat() +. s.coalescedMu.Lock() [L1] +--------------------------------G1,G2 leak------------------------------------------ +``` + +## Cockroach/1055 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#1055]|[pull request]|[patch]| Mixed | Channel & WaitGroup | + +[cockroach#1055]:(cockroach1055_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/1055/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/1055 + +### Description + +1. `Stop()` is called and blocked at `s.stop.Wait()` after acquiring the lock. +2. `StartTask()` is called and attempts to acquire the lock. It is then blocked. +3. `Stop()` never finishes since the task doesn't call SetStopped. + +### Example execution + +```go +G1 G2.0 G2.1 G2.2 G3 +------------------------------------------------------------------------------------------------------------------------------- +s[0].stop.Add(1) [1] +go func() [G2.0] +s[1].stop.Add(1) [1] . +go func() [G2.1] . +s[2].stop.Add(1) [1] . . +go func() [G2.2] . . +go func() [G3] . . . +<-done . . . . +. s[0].StartTask() . . . +. s[0].draining == 0 . . . +. . s[1].StartTask() . . +. . s[1].draining == 0 . . +. . . s[2].StartTask() . +. . . s[2].draining == 0 . +. . . . s[0].Quiesce() +. . . . s[0].mu.Lock() [L1[0]] +. s[0].mu.Lock() [L1[0]] . . . +. s[0].drain.Add(1) [1] . . . +. s[0].mu.Unlock() [L1[0]] . . . +. <-s[0].ShouldStop() . . . +. . . . s[0].draining = 1 +. . . . s[0].drain.Wait() +. . s[0].mu.Lock() [L1[1]] . . +. . s[1].drain.Add(1) [1] . . +. . s[1].mu.Unlock() [L1[1]] . . +. . <-s[1].ShouldStop() . . +. . . s[2].mu.Lock() [L1[2]] . +. . . s[2].drain.Add() [1] . +. . . s[2].mu.Unlock() [L1[2]] . +. . . <-s[2].ShouldStop() . +----------------------------------------------------G1, G2.[0..2], G3 leak----------------------------------------------------- +``` + +## Cockroach/10790 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#10790]|[pull request]|[patch]| Communication | Channel & Context | + +[cockroach#10790]:(cockroach10790_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/10790/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/10790 + +### Description + +It is possible that a message from `ctxDone` will make `beginCmds` +return without draining the channel `ch`, so that anonymous function +goroutines will leak. + +### Example execution + +```go +G1 G2 helper goroutine +----------------------------------------------------- +. . r.sendChans() +r.beginCmds() . . +. . ch1 <- true +<- ch1 . . +. . ch2 <- true +... +. cancel() +<- ch1 +------------------G1 leak---------------------------- +``` + +## Cockroach/13197 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#13197]|[pull request]|[patch]| Communication | Channel & Context | + +[cockroach#13197]:(cockroach13197_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/13197/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/13197 + +### Description + +One goroutine executing `(*Tx).awaitDone()` blocks and +waiting for a signal `context.Done()`. + +### Example execution + +```go +G1 G2 +------------------------------- +begin() +. awaitDone() +return . +. <-tx.ctx.Done() +-----------G2 leaks------------ +``` + +## Cockroach/13755 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#13755]|[pull request]|[patch]| Communication | Channel & Context | + +[cockroach#13755]:(cockroach13755_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/13755/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/13755 + +### Description + +The buggy code does not close the db query result (rows), +so that one goroutine running `(*Rows).awaitDone` is blocked forever. +The blocking goroutine is waiting for cancel signal from context. + +### Example execution + +```go +G1 G2 +--------------------------------------- +initContextClose() +. awaitDone() +return . +. <-tx.ctx.Done() +---------------G2 leaks---------------- +``` + +## Cockroach/1462 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#1462]|[pull request]|[patch]| Mixed | Channel & WaitGroup | + +[cockroach#1462]:(cockroach1462_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/1462/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/1462 + +### Description + +Executing `<-stopper.ShouldStop()` in `processEventsUntil` may cause +goroutines created by `lt.RunWorker` in `lt.start` to be stuck sending +a message over `lt.Events`. The main thread is then stuck at `s.stop.Wait()`, +since the sender goroutines cannot call `s.stop.Done()`. + +### Example execution + +```go +G1 G2 G3 +------------------------------------------------------------------------------------------------------- +NewLocalInterceptableTransport() +lt.start() +lt.stopper.RunWorker() +s.AddWorker() +s.stop.Add(1) [1] +go func() [G2] +stopper.RunWorker() . +s.AddWorker() . +s.stop.Add(1) [2] . +go func() [G3] . +s.Stop() . . +s.Quiesce() . . +. select [default] . +. lt.Events <- interceptMessage(0) . +close(s.stopper) . . +. . select [<-stopper.ShouldStop()] +. . <<>> +s.stop.Wait() . +----------------------------------------------G1,G2 leak----------------------------------------------- +``` + +## Cockroach/16167 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#16167]|[pull request]|[patch]| Resource | Double Locking | + +[cockroach#16167]:(cockroach16167_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/16167/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/16167 + +### Description + +This is another example of goroutine leaks caused by recursively +acquiring `RWLock`. +There are two lock variables (`systemConfigCond` and `systemConfigMu`) +which refer to the same underlying lock. The leak invovlves two goroutines. +The first acquires `systemConfigMu.Lock()`, then tries to acquire `systemConfigMu.RLock()`. +The second acquires `systemConfigMu.Lock()`. +If the second goroutine interleaves in between the two lock operations of the +first goroutine, both goroutines will leak. + +### Example execution + +```go +G1 G2 +--------------------------------------------------------------- +. e.Start() +. e.updateSystemConfig() +e.execParsed() . +e.systemConfigCond.L.Lock() [L1] . +. e.systemConfigMu.Lock() [L1] +e.systemConfigMu.RLock() [L1] . +------------------------G1,G2 leak----------------------------- +``` + +## Cockroach/18101 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#18101]|[pull request]|[patch]| Resource | Double Locking | + +[cockroach#18101]:(cockroach18101_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/18101/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/18101 + +### Description + +The `context.Done()` signal short-circuits the reader goroutine, but not +the senders, leading them to leak. + +### Example execution + +```go +G1 G2 helper goroutine +-------------------------------------------------------------- +restore() +. splitAndScatter() +<-readyForImportCh . +<-readyForImportCh <==> readyForImportCh<- +... +. . cancel() +<> . <> + readyForImportCh<- +-----------------------G2 leaks-------------------------------- +``` + +## Cockroach/2448 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#2448]|[pull request]|[patch]| Communication | Channel | + +[cockroach#2448]:(cockroach2448_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/2448/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/2448 + +### Description + +This bug is caused by two goroutines waiting for each other +to unblock their channels: + +1) `MultiRaft` sends the commit event for the Membership change +2) `store.processRaft` takes it and begins processing +3) another command commits and triggers another `sendEvent`, but + this blocks since `store.processRaft` isn't ready for another + `select`. Consequently the main `MultiRaft` loop is waiting for + that as well. +4) the `Membership` change was applied to the range, and the store + now tries to execute the callback +5) the callback tries to write to `callbackChan`, but that is + consumed by the `MultiRaft` loop, which is currently waiting + for `store.processRaft` to consume from the events channel, + which it will only do after the callback has completed. + +### Example execution + +```go +G1 G2 +-------------------------------------------------------------------------- +s.processRaft() st.start() +select . +. select [default] +. s.handleWriteResponse() +. s.sendEvent() +. select +<-s.multiraft.Events <----> m.Events <- event +. select [default] +. s.handleWriteResponse() +. s.sendEvent() +. select [m.Events<-, <-s.stopper.ShouldStop()] +callback() . +select [ + m.callbackChan<-, + <-s.stopper.ShouldStop() +] . +------------------------------G1,G2 leak---------------------------------- +``` + +## Cockroach/24808 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#24808]|[pull request]|[patch]| Communication | Channel | + +[cockroach#24808]:(cockroach24808_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/24808/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/24808 + +### Description + +When we `Start` the `Compactor`, it may already have received +`Suggestions`, leaking the previously blocking write to a full channel. + +### Example execution + +```go +G1 +------------------------------------------------ +... +compactor.ch <- +compactor.Start() +compactor.ch <- +--------------------G1 leaks-------------------- +``` + +## Cockroach/25456 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#25456]|[pull request]|[patch]| Communication | Channel | + +[cockroach#25456]:(cockroach25456_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/25456/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/25456 + +### Description + +When `CheckConsistency` (in the complete code) returns an error, the queue +checks whether the store is draining to decide whether the error is worth +logging. This check was incorrect and would block until the store actually +started draining. + +### Example execution + +```go +G1 +--------------------------------------- +... +<-repl.store.Stopper().ShouldQuiesce() +---------------G1 leaks---------------- +``` + +## Cockroach/35073 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#35073]|[pull request]|[patch]| Communication | Channel | + +[cockroach#35073]:(cockroach35073_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/35073/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/35073 + +### Description + +Previously, the outbox could fail during startup without closing its +`RowChannel`. This could lead to goroutine leaks in rare cases due +to channel communication mismatch. + +### Example execution + +## Cockroach/35931 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#35931]|[pull request]|[patch]| Communication | Channel | + +[cockroach#35931]:(cockroach35931_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/35931/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/35931 + +### Description + +Previously, if a processor that reads from multiple inputs was waiting +on one input to provide more data, and the other input was full, and +both inputs were connected to inbound streams, it was possible to +cause goroutine leaks during flow cancellation when trying to propagate +the cancellation metadata messages into the flow. The cancellation method +wrote metadata messages to each inbound stream one at a time, so if the +first one was full, the canceller would block and never send a cancellation +message to the second stream, which was the one actually being read from. + +### Example execution + +## Cockroach/3710 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#3710]|[pull request]|[patch]| Resource | RWR Deadlock | + +[cockroach#3710]:(cockroach3710_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/3710/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/3710 + +### Description + +The goroutine leak is caused by acquiring a RLock twice in a call chain. +`ForceRaftLogScanAndProcess(acquire s.mu.RLock())` +`-> MaybeAdd()` +`-> shouldQueue()` +`-> getTruncatableIndexes()` +`->RaftStatus(acquire s.mu.Rlock())` + +### Example execution + +```go +G1 G2 +------------------------------------------------------------ +store.ForceRaftLogScanAndProcess() +s.mu.RLock() +s.raftLogQueue.MaybeAdd() +bq.impl.shouldQueue() +getTruncatableIndexes() +r.store.RaftStatus() +. store.processRaft() +. s.mu.Lock() +s.mu.RLock() +----------------------G1,G2 leak----------------------------- +``` + +## Cockroach/584 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#584]|[pull request]|[patch]| Resource | Double Locking | + +[cockroach#584]:(cockroach584_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/584/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/584 + +### Description + +Missing call to `mu.Unlock()` before the `break` in the loop. + +### Example execution + +```go +G1 +--------------------------- +g.bootstrap() +g.mu.Lock() [L1] +if g.closed { ==> break +g.manage() +g.mu.Lock() [L1] +----------G1 leaks--------- +``` + +## Cockroach/6181 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#6181]|[pull request]|[patch]| Resource | RWR Deadlock | + +[cockroach#6181]:(cockroach6181_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/6181/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/6181 + +### Description + +The same `RWMutex` may be recursively acquired for both reading and writing. + +### Example execution + +```go +G1 G2 G3 ... +----------------------------------------------------------------------------------------------- +testRangeCacheCoalescedRquests() +initTestDescriptorDB() +pauseLookupResumeAndAssert() +return +. doLookupWithToken() +. . doLookupWithToken() +. rc.LookupRangeDescriptor() . +. . rc.LookupRangeDescriptor() +. rdc.rangeCacheMu.RLock() . +. rdc.String() . +. . rdc.rangeCacheMu.RLock() +. . fmt.Printf() +. . rdc.rangeCacheMu.RUnlock() +. . rdc.rangeCacheMu.Lock() +. rdc.rangeCacheMu.RLock() . +-----------------------------------G2,G3,... leak---------------------------------------------- +``` + +## Cockroach/7504 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#7504]|[pull request]|[patch]| Resource | AB-BA Deadlock | + +[cockroach#7504]:(cockroach7504_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/7504/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/7504 + +### Description + +The locks are acquired as `leaseState` and `tableNameCache` in `Release()`, but +as `tableNameCache` and `leaseState` in `AcquireByName`, leading to an AB-BA deadlock. + +### Example execution + +```go +G1 G2 +----------------------------------------------------- +mgr.AcquireByName() mgr.Release() +m.tableNames.get(id) . +c.mu.Lock() [L2] . +. t.release(lease) +. t.mu.Lock() [L3] +. s.mu.Lock() [L1] +lease.mu.Lock() [L1] . +. t.removeLease(s) +. t.tableNameCache.remove() +. c.mu.Lock() [L2] +---------------------G1, G2 leak--------------------- +``` + +## Cockroach/9935 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[cockroach#9935]|[pull request]|[patch]| Resource | Double Locking | + +[cockroach#9935]:(cockroach9935_test.go) +[patch]:https://github.com/cockroachdb/cockroach/pull/9935/files +[pull request]:https://github.com/cockroachdb/cockroach/pull/9935 + +### Description + +This bug is caused by acquiring `l.mu.Lock()` twice. + +### Example execution + +## Etcd/10492 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[etcd#10492]|[pull request]|[patch]| Resource | Double locking | + +[etcd#10492]:(etcd10492_test.go) +[patch]:https://github.com/etcd-io/etcd/pull/10492/files +[pull request]:https://github.com/etcd-io/etcd/pull/10492 + +### Description + +A simple double locking case for lines 19, 31. + +## Etcd/5509 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[etcd#5509]|[pull request]|[patch]| Resource | Double locking | + +[etcd#5509]:(etcd5509_test.go) +[patch]:https://github.com/etcd-io/etcd/pull/5509/files +[pull request]:https://github.com/etcd-io/etcd/pull/5509 + +### Description + +`r.acquire()` returns holding `r.client.mu.RLock()` on a failure path (line 42). +This causes any call to `client.Close()` to leak goroutines. + +## Etcd/6708 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[etcd#6708]|[pull request]|[patch]| Resource | Double locking | + +[etcd#6708]:(etcd6708_test.go) +[patch]:https://github.com/etcd-io/etcd/pull/6708/files +[pull request]:https://github.com/etcd-io/etcd/pull/6708 + +### Description + +Line 54, 49 double locking + +## Etcd/6857 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[etcd#6857]|[pull request]|[patch]| Communication | Channel | + +[etcd#6857]:(etcd6857_test.go) +[patch]:https://github.com/etcd-io/etcd/pull/6857/files +[pull request]:https://github.com/etcd-io/etcd/pull/6857 + +### Description + +Choosing a different case in a `select` statement (`n.stop`) will +lead to goroutine leaks when sending over `n.status`. + +### Example execution + +```go +G1 G2 G3 +------------------------------------------- +n.run() . . +. . n.Stop() +. . n.stop<- +<-n.stop . . +. . <-n.done +close(n.done) . . +return . . +. . return +. n.Status() +. n.status<- +----------------G2 leaks------------------- +``` + +## Etcd/6873 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[etcd#6873]|[pull request]|[patch]| Mixed | Channel & Lock | + +[etcd#6873]:(etcd6873_test.go) +[patch]:https://github.com/etcd-io/etcd/pull/6873/files +[pull request]:https://github.com/etcd-io/etcd/pull/6873 + +### Description + +This goroutine leak involves a goroutine acquiring a lock and being +blocked over a channel operation with no partner, while another tries +to acquire the same lock. + +### Example execution + +```go +G1 G2 G3 +-------------------------------------------------------------- +newWatchBroadcasts() +wbs.update() +wbs.updatec <- +return +. <-wbs.updatec . +. wbs.coalesce() . +. . wbs.stop() +. . wbs.mu.Lock() +. . close(wbs.updatec) +. . <-wbs.donec +. wbs.mu.Lock() . +---------------------G2,G3 leak-------------------------------- +``` + +## Etcd/7492 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[etcd#7492]|[pull request]|[patch]| Mixed | Channel & Lock | + +[etcd#7492]:(etcd7492_test.go) +[patch]:https://github.com/etcd-io/etcd/pull/7492/files +[pull request]:https://github.com/etcd-io/etcd/pull/7492 + +### Description + +This goroutine leak involves a goroutine acquiring a lock and being +blocked over a channel operation with no partner, while another tries +to acquire the same lock. + +### Example execution + +```go +G2 G1 +--------------------------------------------------------------- +. stk.run() +ts.assignSimpleTokenToUser() . +t.simpleTokensMu.Lock() . +t.simpleTokenKeeper.addSimpleToken() . +tm.addSimpleTokenCh <- true . +. <-tm.addSimpleTokenCh +t.simpleTokensMu.Unlock() . +ts.assignSimpleTokenToUser() . +... +t.simpleTokensMu.Lock() +. <-tokenTicker.C +tm.addSimpleTokenCh <- true . +. tm.deleteTokenFunc() +. t.simpleTokensMu.Lock() +---------------------------G1,G2 leak-------------------------- +``` + +## Etcd/7902 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[etcd#7902]|[pull request]|[patch]| Mixed | Channel & Lock | + +[etcd#7902]:(etcd7902_test.go) +[patch]:https://github.com/etcd-io/etcd/pull/7902/files +[pull request]:https://github.com/etcd-io/etcd/pull/7902 + +### Description + +If the follower gooroutine acquires `mu.Lock()` first and calls +`rc.release()`, it will be blocked sending over `rcNextc`. +Only the leader can `close(nextc)` to unblock the follower. +However, in order to invoke `rc.release()`, the leader needs +to acquires `mu.Lock()`. +The fix is to remove the lock and unlock around `rc.release()`. + +### Example execution + +```go +G1 G2 (leader) G3 (follower) +--------------------------------------------------------------------- +runElectionFunc() +doRounds() +wg.Wait() +. ... +. mu.Lock() +. rc.validate() +. rcNextc = nextc +. mu.Unlock() ... +. . mu.Lock() +. . rc.validate() +. . mu.Unlock() +. . mu.Lock() +. . rc.release() +. . <-rcNextc +. mu.Lock() +-------------------------G1,G2,G3 leak-------------------------- +``` + +## Grpc/1275 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[grpc#1275]|[pull request]|[patch]| Communication | Channel | + +[grpc#1275]:(grpc1275_test.go) +[patch]:https://github.com/grpc/grpc-go/pull/1275/files +[pull request]:https://github.com/grpc/grpc-go/pull/1275 + +### Description + +Two goroutines are involved in this leak. The main goroutine +is blocked at `case <- donec`, and is waiting for the second goroutine +to close the channel. +The second goroutine is created by the main goroutine. It is blocked +when calling `stream.Read()`, which invokes `recvBufferRead.Read()`. +The second goroutine is blocked at case `i := r.recv.get()`, and it is +waiting for someone to send a message to this channel. +It is the `client.CloseSream()` method called by the main goroutine that +should send the message, but it is not. The patch is to send out this message. + +### Example execution + +```go +G1 G2 +----------------------------------------------------- +testInflightStreamClosing() +. stream.Read() +. io.ReadFull() +. <-r.recv.get() +CloseStream() +<-donec +---------------------G1, G2 leak--------------------- +``` + +## Grpc/1424 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[grpc#1424]|[pull request]|[patch]| Communication | Channel | + +[grpc#1424]:(grpc1424_test.go) +[patch]:https://github.com/grpc/grpc-go/pull/1424/files +[pull request]:https://github.com/grpc/grpc-go/pull/1424 + +### Description + +The goroutine running `cc.lbWatcher` returns without +draining the `done` channel. + +### Example execution + +```go +G1 G2 G3 +----------------------------------------------------------------- +DialContext() . . +. cc.dopts.balancer.Notify() . +. . cc.lbWatcher() +. <-doneChan +close() +---------------------------G2 leaks------------------------------- +``` + +## Grpc/1460 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[grpc#1460]|[pull request]|[patch]| Mixed | Channel & Lock | + +[grpc#1460]:(grpc1460_test.go) +[patch]:https://github.com/grpc/grpc-go/pull/1460/files +[pull request]:https://github.com/grpc/grpc-go/pull/1460 + +### Description + +When gRPC keepalives are enabled (which isn't the case +by default at this time) and PermitWithoutStream is false +(the default), the client can leak goroutines when transitioning +between having no active stream and having one active +stream.The keepalive() goroutine is stuck at “<-t.awakenKeepalive”, +while the main goroutine is stuck in NewStream() on t.mu.Lock(). + +### Example execution + +```go +G1 G2 +-------------------------------------------- +client.keepalive() +. client.NewStream() +t.mu.Lock() +<-t.awakenKeepalive +. t.mu.Lock() +---------------G1,G2 leak------------------- +``` + +## Grpc/3017 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[grpc#3017]|[pull request]|[patch]| Resource | Missing unlock | + +[grpc#3017]:(grpc3017_test.go) +[patch]:https://github.com/grpc/grpc-go/pull/3017/files +[pull request]:https://github.com/grpc/grpc-go/pull/3017 + +### Description + +Line 65 is an execution path with a missing unlock. + +### Example execution + +```go +G1 G2 G3 +------------------------------------------------------------------------------------------------ +NewSubConn([1]) +ccc.mu.Lock() [L1] +sc = 1 +ccc.subConnToAddr[1] = 1 +go func() [G2] +<-done . +. ccc.RemoveSubConn(1) +. ccc.mu.Lock() +. addr = 1 +. entry = &subConnCacheEntry_grpc3017{} +. cc.subConnCache[1] = entry +. timer = time.AfterFunc() [G3] +. entry.cancel = func() +. sc = ccc.NewSubConn([1]) +. ccc.mu.Lock() [L1] +. entry.cancel() +. !timer.Stop() [true] +. entry.abortDeleting = true +. . ccc.mu.Lock() +. . <<>> +. ccc.RemoveSubConn(1) +. ccc.mu.Lock() [L1] +-------------------------------------------G1, G2 leak----------------------------------------- +``` + +## Grpc/660 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[grpc#660]|[pull request]|[patch]| Communication | Channel | + +[grpc#660]:(grpc660_test.go) +[patch]:https://github.com/grpc/grpc-go/pull/660/files +[pull request]:https://github.com/grpc/grpc-go/pull/660 + +### Description + +The parent function could return without draining the done channel. + +### Example execution + +```go +G1 G2 helper goroutine +------------------------------------------------------------- +doCloseLoopUnary() +. bc.stop <- true +<-bc.stop +return +. done <- +----------------------G2 leak-------------------------------- +``` + +## Grpc/795 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[grpc#795]|[pull request]|[patch]| Resource | Double locking | + +[grpc#795]:(grpc795_test.go) +[patch]:https://github.com/grpc/grpc-go/pull/795/files +[pull request]:https://github.com/grpc/grpc-go/pull/795 + +### Description + +Line 20 is an execution path with a missing unlock. + +## Grpc/862 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[grpc#862]|[pull request]|[patch]| Communication | Channel & Context | + +[grpc#862]:(grpc862_test.go) +[patch]:https://github.com/grpc/grpc-go/pull/862/files +[pull request]:https://github.com/grpc/grpc-go/pull/862 + +### Description + +When return value `conn` is `nil`, `cc(ClientConn)` is not closed. +The goroutine executing resetAddrConn is leaked. The patch is to +close `ClientConn` in `defer func()`. + +### Example execution + +```go +G1 G2 +--------------------------------------- +DialContext() +. cc.resetAddrConn() +. resetTransport() +. <-ac.ctx.Done() +--------------G2 leak------------------ +``` + +## Hugo/3251 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[hugo#3251]|[pull request]|[patch]| Resource | RWR deadlock | + +[hugo#3251]:(hugo3251_test.go) +[patch]:https://github.com/gohugoio/hugo/pull/3251/files +[pull request]:https://github.com/gohugoio/hugo/pull/3251 + +### Description + +A goroutine can hold `Lock()` at line 20 then acquire `RLock()` at +line 29. `RLock()` at line 29 will never be acquired because `Lock()` +at line 20 will never be released. + +### Example execution + +```go +G1 G2 G3 +------------------------------------------------------------------------------------------ +wg.Add(1) [W1: 1] +go func() [G2] +go func() [G3] +. resGetRemote() +. remoteURLLock.URLLock(url) +. l.Lock() [L1] +. l.m[url] = &sync.Mutex{} [L2] +. l.m[url].Lock() [L2] +. l.Unlock() [L1] +. . resGetRemote() +. . remoteURLLock.URLLock(url) +. . l.Lock() [L1] +. . l.m[url].Lock() [L2] +. remoteURLLock.URLUnlock(url) +. l.RLock() [L1] +... +wg.Wait() [W1] +----------------------------------------G1,G2,G3 leak-------------------------------------- +``` + +## Hugo/5379 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[hugo#5379]|[pull request]|[patch]| Resource | Double locking | + +[hugo#5379]:(hugo5379_test.go) +[patch]:https://github.com/gohugoio/hugo/pull/5379/files +[pull request]:https://github.com/gohugoio/hugo/pull/5379 + +### Description + +A goroutine first acquire `contentInitMu` at line 99 then +acquire the same `Mutex` at line 66 + +## Istio/16224 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[istio#16224]|[pull request]|[patch]| Mixed | Channel & Lock | + +[istio#16224]:(istio16224_test.go) +[patch]:https://github.com/istio/istio/pull/16224/files +[pull request]:https://github.com/istio/istio/pull/16224 + +### Description + +A goroutine holds a `Mutex` at line 91 and is then blocked at line 93. +Another goroutine attempts to acquire the same `Mutex` at line 101 to +further drains the same channel at 103. + +## Istio/17860 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[istio#17860]|[pull request]|[patch]| Communication | Channel | + +[istio#17860]:(istio17860_test.go) +[patch]:https://github.com/istio/istio/pull/17860/files +[pull request]:https://github.com/istio/istio/pull/17860 + +### Description + +`a.statusCh` can't be drained at line 70. + +## Istio/18454 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[istio#18454]|[pull request]|[patch]| Communication | Channel & Context | + +[istio#18454]:(istio18454_test.go) +[patch]:https://github.com/istio/istio/pull/18454/files +[pull request]:https://github.com/istio/istio/pull/18454 + +### Description + +`s.timer.Stop()` at line 56 and 61 can be called concurrency +(i.e. from their entry point at line 104 and line 66). +See [Timer](https://golang.org/pkg/time/#Timer). + +## Kubernetes/10182 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#10182]|[pull request]|[patch]| Mixed | Channel & Lock | + +[kubernetes#10182]:(kubernetes10182_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/10182/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/10182 + +### Description + +Goroutine 1 is blocked on a lock held by goroutine 3, +while goroutine 3 is blocked on sending message to `ch`, +which is read by goroutine 1. + +### Example execution + +```go +G1 G2 G3 +------------------------------------------------------------------------------- +s.Start() +s.syncBatch() +. s.SetPodStatus() +. s.podStatusesLock.Lock() +<-s.podStatusChannel <===> s.podStatusChannel <- true +. s.podStatusesLock.Unlock() +. return +s.DeletePodStatus() . +. . s.podStatusesLock.Lock() +. . s.podStatusChannel <- true +s.podStatusesLock.Lock() +-----------------------------G1,G3 leak----------------------------------------- +``` + +## Kubernetes/11298 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#11298]|[pull request]|[patch]| Communication | Channel & Condition Variable | + +[kubernetes#11298]:(kubernetes11298_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/11298/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/11298 + +### Description + +`n.node` used the `n.lock` as underlaying locker. The service loop initially +locked it, the `Notify` function tried to lock it before calling `n.node.Signal()`, +leading to a goroutine leak. `n.cond.Signal()` at line 59 and line 81 are not +guaranteed to unblock the `n.cond.Wait` at line 56. + +## Kubernetes/13135 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#13135]|[pull request]|[patch]| Resource | AB-BA deadlock | + +[kubernetes#13135]:(kubernetes13135_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/13135/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/13135 + +### Description + +```go +G1 G2 G3 +---------------------------------------------------------------------------------- +NewCacher() +watchCache.SetOnReplace() +watchCache.SetOnEvent() +. cacher.startCaching() +. c.Lock() +. c.reflector.ListAndWatch() +. r.syncWith() +. r.store.Replace() +. w.Lock() +. w.onReplace() +. cacher.initOnce.Do() +. cacher.Unlock() +return cacher . +. . c.watchCache.Add() +. . w.processEvent() +. . w.Lock() +. cacher.startCaching() . +. c.Lock() . +... +. c.Lock() +. w.Lock() +--------------------------------G2,G3 leak----------------------------------------- +``` + +## Kubernetes/1321 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#1321]|[pull request]|[patch]| Mixed | Channel & Lock | + +[kubernetes#1321]:(kubernetes1321_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/1321/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/1321 + +### Description + +This is a lock-channel bug. The first goroutine invokes +`distribute()`, which holds `m.lock.Lock()`, while blocking +at sending message to `w.result`. The second goroutine +invokes `stopWatching()` function, which can unblock the first +goroutine by closing `w.result`. However, in order to close `w.result`, +`stopWatching()` function needs to acquire `m.lock.Lock()`. + +The fix is to introduce another channel and put receive message +from the second channel in the same `select` statement as the +`w.result`. Close the second channel can unblock the first +goroutine, while no need to hold `m.lock.Lock()`. + +### Example execution + +```go +G1 G2 +---------------------------------------------- +testMuxWatcherClose() +NewMux() +. m.loop() +. m.distribute() +. m.lock.Lock() +. w.result <- true +w := m.Watch() +w.Stop() +mw.m.stopWatching() +m.lock.Lock() +---------------G1,G2 leak--------------------- +``` + +## Kubernetes/25331 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#25331]|[pull request]|[patch]| Communication | Channel & Context | + +[kubernetes#25331]:(kubernetes25331_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/25331/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/25331 + +### Description + +A potential goroutine leak occurs when an error has happened, +blocking `resultChan`, while cancelling context in `Stop()`. + +### Example execution + +```go +G1 G2 +------------------------------------ +wc.run() +. wc.Stop() +. wc.errChan <- +. wc.cancel() +<-wc.errChan +wc.cancel() +wc.resultChan <- +-------------G1 leak---------------- +``` + +## Kubernetes/26980 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#26980]|[pull request]|[patch]| Mixed | Channel & Lock | + +[kubernetes#26980]:(kubernetes26980_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/26980/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/26980 + +### Description + +A goroutine holds a `Mutex` at line 24 and blocked at line 35. +Another goroutine blocked at line 58 by acquiring the same `Mutex`. + +## Kubernetes/30872 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#30872]|[pull request]|[patch]| Resource | AB-BA deadlock | + +[kubernetes#30872]:(kubernetes30872_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/30872/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/30872 + +### Description + +The lock is acquired both at lines 92 and 157. + +## Kubernetes/38669 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#38669]|[pull request]|[patch]| Communication | Channel | + +[kubernetes#38669]:(kubernetes38669_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/38669/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/38669 + +### Description + +No sender for line 33. + +## Kubernetes/5316 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#5316]|[pull request]|[patch]| Communication | Channel | + +[kubernetes#5316]:(kubernetes5316_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/5316/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/5316 + +### Description + +If the main goroutine selects a case that doesn’t consumes +the channels, the anonymous goroutine will be blocked on sending +to channel. + +### Example execution + +```go +G1 G2 +-------------------------------------- +finishRequest() +. fn() +time.After() +. errCh<-/ch<- +--------------G2 leaks---------------- +``` + +## Kubernetes/58107 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#58107]|[pull request]|[patch]| Resource | RWR deadlock | + +[kubernetes#58107]:(kubernetes58107_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/58107/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/58107 + +### Description + +The rules for read and write lock: allows concurrent read lock; +write lock has higher priority than read lock. + +There are two queues (queue 1 and queue 2) involved in this bug, +and the two queues are protected by the same read-write lock +(`rq.workerLock.RLock()`). Before getting an element from queue 1 or +queue 2, `rq.workerLock.RLock()` is acquired. If the queue is empty, +`cond.Wait()` will be invoked. There is another goroutine (goroutine D), +which will periodically invoke `rq.workerLock.Lock()`. Under the following +situation, deadlock will happen. Queue 1 is empty, so that some goroutines +hold `rq.workerLock.RLock()`, and block at `cond.Wait()`. Goroutine D is +blocked when acquiring `rq.workerLock.Lock()`. Some goroutines try to process +jobs in queue 2, but they are blocked when acquiring `rq.workerLock.RLock()`, +since write lock has a higher priority. + +The fix is to not acquire `rq.workerLock.RLock()`, while pulling data +from any queue. Therefore, when a goroutine is blocked at `cond.Wait()`, +`rq.workLock.RLock()` is not held. + +### Example execution + +```go +G3 G4 G5 +-------------------------------------------------------------------- +. . Sync() +rq.workerLock.RLock() . . +q.cond.Wait() . . +. . rq.workerLock.Lock() +. rq.workerLock.RLock() +. q.cond.L.Lock() +-----------------------------G3,G4,G5 leak----------------------------- +``` + +## Kubernetes/62464 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#62464]|[pull request]|[patch]| Resource | RWR deadlock | + +[kubernetes#62464]:(kubernetes62464_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/62464/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/62464 + +### Description + +This is another example for recursive read lock bug. It has +been noticed by the go developers that RLock should not be +recursively used in the same thread. + +### Example execution + +```go +G1 G2 +-------------------------------------------------------- +m.reconcileState() +m.state.GetCPUSetOrDefault() +s.RLock() +s.GetCPUSet() +. p.RemoveContainer() +. s.GetDefaultCPUSet() +. s.SetDefaultCPUSet() +. s.Lock() +s.RLock() +---------------------G1,G2 leak-------------------------- +``` + +## Kubernetes/6632 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#6632]|[pull request]|[patch]| Mixed | Channel & Lock | + +[kubernetes#6632]:(kubernetes6632_test.go) +[patch]:https://github.com/kubernetes/kubernetes/pull/6632/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/6632 + +### Description + +When `resetChan` is full, `WriteFrame` holds the lock and blocks +on the channel. Then `monitor()` fails to close the `resetChan` +because the lock is already held by `WriteFrame`. + + +### Example execution + +```go +G1 G2 helper goroutine +---------------------------------------------------------------- +i.monitor() +<-i.conn.closeChan +. i.WriteFrame() +. i.writeLock.Lock() +. i.resetChan <- +. . i.conn.closeChan<- +i.writeLock.Lock() +----------------------G1,G2 leak-------------------------------- +``` + +## Kubernetes/70277 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[kubernetes#70277]|[pull request]|[patch]| Communication | Channel | + +[kubernetes#70277]:kubernetes70277_test.go +[patch]:https://github.com/kubernetes/kubernetes/pull/70277/files +[pull request]:https://github.com/kubernetes/kubernetes/pull/70277 + +### Description + +`wait.poller()` returns a function with type `WaitFunc`. +the function creates a goroutine and the goroutine only +quits when after or done closed. + +The `doneCh` defined at line 70 is never closed. + +## Moby/17176 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#17176]|[pull request]|[patch]| Resource | Double locking | + +[moby#17176]:(moby17176_test.go) +[patch]:https://github.com/moby/moby/pull/17176/files +[pull request]:https://github.com/moby/moby/pull/17176 + +### Description + +`devices.nrDeletedDevices` takes `devices.Lock()` but does +not release it (line 36) if there are no deleted devices. This will block +other goroutines trying to acquire `devices.Lock()`. + +## Moby/21233 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#21233]|[pull request]|[patch]| Communication | Channel | + +[moby#21233]:(moby21233_test.go) +[patch]:https://github.com/moby/moby/pull/21233/files +[pull request]:https://github.com/moby/moby/pull/21233 + +### Description + +This test was checking that it received every progress update that was +produced. But delivery of these intermediate progress updates is not +guaranteed. A new update can overwrite the previous one if the previous +one hasn't been sent to the channel yet. + +The call to `t.Fatalf` terminated the current goroutine which was consuming +the channel, which caused a deadlock and eventual test timeout rather +than a proper failure message. + +### Example execution + +```go +G1 G2 G3 +---------------------------------------------------------- +testTransfer() . . +tm.Transfer() . . +t.Watch() . . +. WriteProgress() . +. ProgressChan<- . +. . <-progressChan +. ... ... +. return . +. <-progressChan +<-watcher.running +----------------------G1,G3 leak-------------------------- +``` + +## Moby/25384 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#25384]|[pull request]|[patch]| Mixed | Misuse WaitGroup | + +[moby#25384]:(moby25384_test.go) +[patch]:https://github.com/moby/moby/pull/25384/files +[pull request]:https://github.com/moby/moby/pull/25384 + +### Description + +When `n=1` (where `n` is `len(pm.plugins)`), the location of `group.Wait()` doesn’t matter. +When `n > 1`, `group.Wait()` is invoked in each iteration. Whenever +`group.Wait()` is invoked, it waits for `group.Done()` to be executed `n` times. +However, `group.Done()` is only executed once in one iteration. + +Misuse of sync.WaitGroup + +## Moby/27782 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#27782]|[pull request]|[patch]| Communication | Channel & Condition Variable | + +[moby#27782]:(moby27782_test.go) +[patch]:https://github.com/moby/moby/pull/27782/files +[pull request]:https://github.com/moby/moby/pull/27782 + +### Description + +### Example execution + +```go +G1 G2 G3 +----------------------------------------------------------------------- +InitializeStdio() +startLogging() +l.ReadLogs() +NewLogWatcher() +. l.readLogs() +container.Reset() . +LogDriver.Close() . +r.Close() . +close(w.closeNotifier) . +. followLogs(logWatcher) +. watchFile() +. New() +. NewEventWatcher() +. NewWatcher() +. . w.readEvents() +. . event.ignoreLinux() +. . return false +. <-logWatcher.WatchClose() . +. fileWatcher.Remove() . +. w.cv.Wait() . +. . w.Events <- event +------------------------------G2,G3 leak------------------------------- +``` + +## Moby/28462 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#28462]|[pull request]|[patch]| Mixed | Channel & Lock | + +[moby#28462]:(moby28462_test.go) +[patch]:https://github.com/moby/moby/pull/28462/files +[pull request]:https://github.com/moby/moby/pull/28462 + +### Description + +One goroutine may acquire a lock and try to send a message over channel `stop`, +while the other will try to acquire the same lock. With the wrong ordering, +both goroutines will leak. + +### Example execution + +```go +G1 G2 +-------------------------------------------------------------- +monitor() +handleProbeResult() +. d.StateChanged() +. c.Lock() +. d.updateHealthMonitorElseBranch() +. h.CloseMonitorChannel() +. s.stop <- struct{}{} +c.Lock() +----------------------G1,G2 leak------------------------------ +``` + +## Moby/30408 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#30408]|[pull request]|[patch]| Communication | Condition Variable | + +[moby#30408]:(moby30408_test.go) +[patch]:https://github.com/moby/moby/pull/30408/files +[pull request]:https://github.com/moby/moby/pull/30408 + +### Description + +`Wait()` at line 22 has no corresponding `Signal()` or `Broadcast()`. + +### Example execution + +```go +G1 G2 +------------------------------------------ +testActive() +. p.waitActive() +. p.activateWait.L.Lock() +. p.activateWait.Wait() +<-done +-----------------G1,G2 leak--------------- +``` + +## Moby/33781 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#33781]|[pull request]|[patch]| Communication | Channel & Context | + +[moby#33781]:(moby33781_test.go) +[patch]:https://github.com/moby/moby/pull/33781/files +[pull request]:https://github.com/moby/moby/pull/33781 + +### Description + +The goroutine created using an anonymous function is blocked +sending a message over an unbuffered channel. However there +exists a path in the parent goroutine where the parent function +will return without draining the channel. + +### Example execution + +```go +G1 G2 G3 +---------------------------------------- +monitor() . +<-time.After() . +. . +<-stop stop<- +. +cancelProbe() +return +. result<- +----------------G3 leak------------------ +``` + +## Moby/36114 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#36114]|[pull request]|[patch]| Resource | Double locking | + +[moby#36114]:(moby36114_test.go) +[patch]:https://github.com/moby/moby/pull/36114/files +[pull request]:https://github.com/moby/moby/pull/36114 + +### Description + +The the lock for the struct svm has already been locked when calling +`svm.hotRemoveVHDsAtStart()`. + +## Moby/4951 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#4951]|[pull request]|[patch]| Resource | AB-BA deadlock | + +[moby#4951]:(moby4951_test.go) +[patch]:https://github.com/moby/moby/pull/4951/files +[pull request]:https://github.com/moby/moby/pull/4951 + +### Description + +The root cause and patch is clearly explained in the commit +description. The global lock is `devices.Lock()`, and the device +lock is `baseInfo.lock.Lock()`. It is very likely that this bug +can be reproduced. + +## Moby/7559 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[moby#7559]|[pull request]|[patch]| Resource | Double locking | + +[moby#7559]:(moby7559_test.go) +[patch]:https://github.com/moby/moby/pull/7559/files +[pull request]:https://github.com/moby/moby/pull/7559 + +### Description + +Line 25 is missing a call to `.Unlock`. + +### Example execution + +```go +G1 +--------------------------- +proxy.connTrackLock.Lock() +if err != nil { continue } +proxy.connTrackLock.Lock() +-----------G1 leaks-------- +``` + +## Serving/2137 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[serving#2137]|[pull request]|[patch]| Mixed | Channel & Lock | + +[serving#2137]:(serving2137_test.go) +[patch]:https://github.com/ knative/serving/pull/2137/files +[pull request]:https://github.com/ knative/serving/pull/2137 + +### Description + +### Example execution + +```go +G1 G2 G3 +---------------------------------------------------------------------------------- +b.concurrentRequests(2) . . +b.concurrentRequest() . . +r.lock.Lock() . . +. start.Done() . +start.Wait() . . +b.concurrentRequest() . . +r.lock.Lock() . . +. . start.Done() +start.Wait() . . +unlockAll(locks) . . +unlock(lc) . . +req.lock.Unlock() . . +ok := <-req.accepted . . +. b.Maybe() . +. b.activeRequests <- t . +. thunk() . +. r.lock.Lock() . +. . b.Maybe() +. . b.activeRequests <- t +----------------------------G1,G2,G3 leak----------------------------------------- +``` + +## Syncthing/4829 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[syncthing#4829]|[pull request]|[patch]| Resource | Double locking | + +[syncthing#4829]:(syncthing4829_test.go) +[patch]:https://github.com/syncthing/syncthing/pull/4829/files +[pull request]:https://github.com/syncthing/syncthing/pull/4829 + +### Description + +Double locking at line 17 and line 30. + +### Example execution + +```go +G1 +--------------------------- +mapping.clearAddresses() +m.mut.Lock() [L2] +m.notify(...) +m.mut.RLock() [L2] +----------G1 leaks--------- +``` + +## Syncthing/5795 + +| Bug ID | Ref | Patch | Type | Sub-type | +| ---- | ---- | ---- | ---- | ---- | +|[syncthing#5795]|[pull request]|[patch]| Communication | Channel | + +[syncthing#5795]:(syncthing5795_test.go) +[patch]:https://github.com/syncthing/syncthing/pull/5795/files +[pull request]:https://github.com/syncthing/syncthing/pull/5795 + +### Description + +`<-c.dispatcherLoopStopped` at line 82 is blocking forever because +`dispatcherLoop()` is blocking at line 72. + +### Example execution + +```go +G1 G2 +-------------------------------------------------------------- +c.Start() +go c.dispatcherLoop() [G3] +. select [<-c.inbox, <-c.closed] +c.inbox <- <================> [<-c.inbox] +<-c.dispatcherLoopStopped . +. default +. c.ccFn()/c.Close() +. close(c.closed) +. <-c.dispatcherLoopStopped +---------------------G1,G2 leak------------------------------- +``` \ No newline at end of file diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach10214.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach10214.go new file mode 100644 index 00000000000000..4f5ef3b0fc32fc --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach10214.go @@ -0,0 +1,145 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/10214 + * Buggy version: 7207111aa3a43df0552509365fdec741a53f873f + * fix commit-id: 27e863d90ab0660494778f1c35966cc5ddc38e32 + * Flaky: 3/100 + * Description: This goroutine leak is caused by different order when acquiring + * coalescedMu.Lock() and raftMu.Lock(). The fix is to refactor sendQueuedHeartbeats() + * so that cockroachdb can unlock coalescedMu before locking raftMu. + */ +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" + "unsafe" +) + +func init() { + register("Cockroach10214", Cockroach10214) +} + +type Store_cockroach10214 struct { + coalescedMu struct { + sync.Mutex // L1 + heartbeatResponses []int + } + mu struct { + replicas map[int]*Replica_cockroach10214 + } +} + +func (s *Store_cockroach10214) sendQueuedHeartbeats() { + s.coalescedMu.Lock() // L1 acquire + defer s.coalescedMu.Unlock() // L2 release + for i := 0; i < len(s.coalescedMu.heartbeatResponses); i++ { + s.sendQueuedHeartbeatsToNode() // L2 + } +} + +func (s *Store_cockroach10214) sendQueuedHeartbeatsToNode() { + for i := 0; i < len(s.mu.replicas); i++ { + r := s.mu.replicas[i] + r.reportUnreachable() // L2 + } +} + +type Replica_cockroach10214 struct { + raftMu sync.Mutex // L2 + mu sync.Mutex // L3 + store *Store_cockroach10214 +} + +func (r *Replica_cockroach10214) reportUnreachable() { + r.raftMu.Lock() // L2 acquire + time.Sleep(time.Millisecond) + defer r.raftMu.Unlock() // L2 release +} + +func (r *Replica_cockroach10214) tick() { + r.raftMu.Lock() // L2 acquire + defer r.raftMu.Unlock() // L2 release + r.tickRaftMuLocked() +} + +func (r *Replica_cockroach10214) tickRaftMuLocked() { + r.mu.Lock() // L3 acquire + defer r.mu.Unlock() // L3 release + if r.maybeQuiesceLocked() { + return + } +} + +func (r *Replica_cockroach10214) maybeQuiesceLocked() bool { + for i := 0; i < 2; i++ { + if !r.maybeCoalesceHeartbeat() { + return true + } + } + return false +} + +func (r *Replica_cockroach10214) maybeCoalesceHeartbeat() bool { + msgtype := uintptr(unsafe.Pointer(r)) % 3 + switch msgtype { + case 0, 1, 2: + r.store.coalescedMu.Lock() // L1 acquire + default: + return false + } + r.store.coalescedMu.Unlock() // L1 release + return true +} + +func Cockroach10214() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 1000; i++ { + go func() { + store := &Store_cockroach10214{} + responses := &store.coalescedMu.heartbeatResponses + *responses = append(*responses, 1, 2) + store.mu.replicas = make(map[int]*Replica_cockroach10214) + + rp1 := &Replica_cockroach10214{ // L2,3[0] + store: store, + } + rp2 := &Replica_cockroach10214{ // L2,3[1] + store: store, + } + store.mu.replicas[0] = rp1 + store.mu.replicas[1] = rp2 + + go store.sendQueuedHeartbeats() // G1 + go rp1.tick() // G2 + }() + } +} + +// Example of goroutine leak trace: +// +// G1 G2 +//------------------------------------------------------------------------------------ +// s.sendQueuedHeartbeats() . +// s.coalescedMu.Lock() [L1] . +// s.sendQueuedHeartbeatsToNode() . +// s.mu.replicas[0].reportUnreachable() . +// s.mu.replicas[0].raftMu.Lock() [L2] . +// . s.mu.replicas[0].tick() +// . s.mu.replicas[0].raftMu.Lock() [L2] +// . s.mu.replicas[0].tickRaftMuLocked() +// . s.mu.replicas[0].mu.Lock() [L3] +// . s.mu.replicas[0].maybeQuiesceLocked() +// . s.mu.replicas[0].maybeCoalesceHeartbeat() +// . s.coalescedMu.Lock() [L1] +//--------------------------------G1,G2 leak------------------------------------------ \ No newline at end of file diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1055.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1055.go new file mode 100644 index 00000000000000..687baed25a2a44 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1055.go @@ -0,0 +1,115 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime/pprof" + "sync" + "sync/atomic" + "time" +) + +func init() { + register("Cockroach1055", Cockroach1055) +} + +type Stopper_cockroach1055 struct { + stopper chan struct{} + stop sync.WaitGroup + mu sync.Mutex + draining int32 + drain sync.WaitGroup +} + +func (s *Stopper_cockroach1055) AddWorker() { + s.stop.Add(1) +} + +func (s *Stopper_cockroach1055) ShouldStop() <-chan struct{} { + if s == nil { + return nil + } + return s.stopper +} + +func (s *Stopper_cockroach1055) SetStopped() { + if s != nil { + s.stop.Done() + } +} + +func (s *Stopper_cockroach1055) Quiesce() { + s.mu.Lock() + defer s.mu.Unlock() + s.draining = 1 + s.drain.Wait() + s.draining = 0 +} + +func (s *Stopper_cockroach1055) Stop() { + s.mu.Lock() // L1 + defer s.mu.Unlock() + atomic.StoreInt32(&s.draining, 1) + s.drain.Wait() + close(s.stopper) + s.stop.Wait() +} + +func (s *Stopper_cockroach1055) StartTask() bool { + if atomic.LoadInt32(&s.draining) == 0 { + s.mu.Lock() + defer s.mu.Unlock() + s.drain.Add(1) + return true + } + return false +} + +func NewStopper_cockroach1055() *Stopper_cockroach1055 { + return &Stopper_cockroach1055{ + stopper: make(chan struct{}), + } +} + +func Cockroach1055() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i <= 1000; i++ { + go func() { // G1 + var stoppers []*Stopper_cockroach1055 + for i := 0; i < 2; i++ { + stoppers = append(stoppers, NewStopper_cockroach1055()) + } + + for i := range stoppers { + s := stoppers[i] + s.AddWorker() + go func() { // G2 + s.StartTask() + <-s.ShouldStop() + s.SetStopped() + }() + } + + done := make(chan struct{}) + go func() { // G3 + for _, s := range stoppers { + s.Quiesce() + } + for _, s := range stoppers { + s.Stop() + } + close(done) + }() + + <-done + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach10790.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach10790.go new file mode 100644 index 00000000000000..636f45b3e0e765 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach10790.go @@ -0,0 +1,98 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/10790 + * Buggy version: 96b5452557ebe26bd9d85fe7905155009204d893 + * fix commit-id: f1a5c19125c65129b966fbdc0e6408e8df214aba + * Flaky: 28/100 + * Description: + * It is possible that a message from ctxDone will make the function beginCmds + * returns without draining the channel ch, so that goroutines created by anonymous + * function will leak. + */ + +package main + +import ( + "context" + "os" + "runtime/pprof" + "time" +) + +func init() { + register("Cockroach10790", Cockroach10790) +} + +type Replica_cockroach10790 struct { + chans []chan bool +} + +func (r *Replica_cockroach10790) beginCmds(ctx context.Context) { + ctxDone := ctx.Done() + for _, ch := range r.chans { + select { + case <-ch: + case <-ctxDone: + go func() { // G3 + for _, ch := range r.chans { + <-ch + } + }() + } + } +} + +func (r *Replica_cockroach10790) sendChans(ctx context.Context) { + for _, ch := range r.chans { + select { + case ch <- true: + case <-ctx.Done(): + return + } + } +} + +func NewReplica_cockroach10790() *Replica_cockroach10790 { + r := &Replica_cockroach10790{} + r.chans = append(r.chans, make(chan bool), make(chan bool)) + return r +} + +// Example of goroutine leak trace: +// +// G1 G2 G3 helper goroutine +//-------------------------------------------------------------------------------------- +// . . r.sendChans() +// r.beginCmds() . . +// . . ch1 <- +// <-ch1 <================================================> ch1 <- +// . . select [ch2<-, <-ctx.Done()] +// . cancel() . +// . <> [<-ctx.Done()] ==> return +// . <> +// go func() [G3] . +// . <-ch1 +// ------------------------------G3 leaks---------------------------------------------- +// + +func Cockroach10790() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + r := NewReplica_cockroach10790() + ctx, cancel := context.WithCancel(context.Background()) + go r.sendChans(ctx) // helper goroutine + go r.beginCmds(ctx) // G1 + go cancel() // G2 + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach13197.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach13197.go new file mode 100644 index 00000000000000..a0a9a792676692 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach13197.go @@ -0,0 +1,82 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/13197 + * Buggy version: fff27aedabafe20cef57f75905fe340cab48c2a4 + * fix commit-id: 9bf770cd8f6eaff5441b80d3aec1a5614e8747e1 + * Flaky: 100/100 + * Description: One goroutine executing (*Tx).awaitDone() blocks + * waiting for a signal over context.Done() that never comes. + */ +package main + +import ( + "context" + "os" + "runtime" + "runtime/pprof" +) + +func init() { + register("Cockroach13197", Cockroach13197) +} + +type DB_cockroach13197 struct{} + +func (db *DB_cockroach13197) begin(ctx context.Context) *Tx_cockroach13197 { + ctx, cancel := context.WithCancel(ctx) + tx := &Tx_cockroach13197{ + cancel: cancel, + ctx: ctx, + } + go tx.awaitDone() // G2 + return tx +} + +type Tx_cockroach13197 struct { + cancel context.CancelFunc + ctx context.Context +} + +func (tx *Tx_cockroach13197) awaitDone() { + <-tx.ctx.Done() +} + +func (tx *Tx_cockroach13197) Rollback() { + tx.rollback() +} + +func (tx *Tx_cockroach13197) rollback() { + tx.close() +} + +func (tx *Tx_cockroach13197) close() { + tx.cancel() +} + +// Example of goroutine leak trace: +// +// G1 G2 +//-------------------------------- +// begin() +// . awaitDone() +// <> . +// <-tx.ctx.Done() +//------------G2 leak------------- + +func Cockroach13197() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + db := &DB_cockroach13197{} + db.begin(context.Background()) // G1 +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach13755.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach13755.go new file mode 100644 index 00000000000000..5ef6fa1e28a06d --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach13755.go @@ -0,0 +1,66 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/13755 + * Buggy version: 7acb881bbb8f23e87b69fce9568d9a3316b5259c + * fix commit-id: ef906076adc1d0e3721944829cfedfed51810088 + * Flaky: 100/100 + */ + +package main + +import ( + "context" + "os" + "runtime" + "runtime/pprof" +) + +func init() { + register("Cockroach13755", Cockroach13755) +} + +type Rows_cockroach13755 struct { + cancel context.CancelFunc +} + +func (rs *Rows_cockroach13755) initContextClose(ctx context.Context) { + ctx, rs.cancel = context.WithCancel(ctx) + go rs.awaitDone(ctx) +} + +func (rs *Rows_cockroach13755) awaitDone(ctx context.Context) { + <-ctx.Done() + rs.close(ctx.Err()) +} + +func (rs *Rows_cockroach13755) close(err error) { + rs.cancel() +} + +// Example of goroutine leak trace: +// +// G1 G2 +//---------------------------------------- +// initContextClose() +// . awaitDone() +// <> . +// <-tx.ctx.Done() +//----------------G2 leak----------------- + +func Cockroach13755() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + rs := &Rows_cockroach13755{} + rs.initContextClose(context.Background()) +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1462.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1462.go new file mode 100644 index 00000000000000..108d7884a3d82b --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1462.go @@ -0,0 +1,167 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Cockroach1462", Cockroach1462) +} + +type Stopper_cockroach1462 struct { + stopper chan struct{} + stopped chan struct{} + stop sync.WaitGroup + mu sync.Mutex + drain *sync.Cond + draining bool + numTasks int +} + +func NewStopper_cockroach1462() *Stopper_cockroach1462 { + s := &Stopper_cockroach1462{ + stopper: make(chan struct{}), + stopped: make(chan struct{}), + } + s.drain = sync.NewCond(&s.mu) + return s +} + +func (s *Stopper_cockroach1462) RunWorker(f func()) { + s.AddWorker() + go func() { // G2, G3 + defer s.SetStopped() + f() + }() +} + +func (s *Stopper_cockroach1462) AddWorker() { + s.stop.Add(1) +} +func (s *Stopper_cockroach1462) StartTask() bool { + s.mu.Lock() + runtime.Gosched() + defer s.mu.Unlock() + if s.draining { + return false + } + s.numTasks++ + return true +} + +func (s *Stopper_cockroach1462) FinishTask() { + s.mu.Lock() + runtime.Gosched() + defer s.mu.Unlock() + s.numTasks-- + s.drain.Broadcast() +} +func (s *Stopper_cockroach1462) SetStopped() { + if s != nil { + s.stop.Done() + } +} +func (s *Stopper_cockroach1462) ShouldStop() <-chan struct{} { + if s == nil { + return nil + } + return s.stopper +} + +func (s *Stopper_cockroach1462) Quiesce() { + s.mu.Lock() + runtime.Gosched() + defer s.mu.Unlock() + s.draining = true + for s.numTasks > 0 { + // Unlock s.mu, wait for the signal, and lock s.mu. + s.drain.Wait() + } +} + +func (s *Stopper_cockroach1462) Stop() { + s.Quiesce() + close(s.stopper) + s.stop.Wait() + s.mu.Lock() + runtime.Gosched() + defer s.mu.Unlock() + close(s.stopped) +} + +type interceptMessage_cockroach1462 int + +type localInterceptableTransport_cockroach1462 struct { + mu sync.Mutex + Events chan interceptMessage_cockroach1462 + stopper *Stopper_cockroach1462 +} + +func (lt *localInterceptableTransport_cockroach1462) Close() {} + +type Transport_cockroach1462 interface { + Close() +} + +func NewLocalInterceptableTransport_cockroach1462(stopper *Stopper_cockroach1462) Transport_cockroach1462 { + lt := &localInterceptableTransport_cockroach1462{ + Events: make(chan interceptMessage_cockroach1462), + stopper: stopper, + } + lt.start() + return lt +} + +func (lt *localInterceptableTransport_cockroach1462) start() { + lt.stopper.RunWorker(func() { + for { + select { + case <-lt.stopper.ShouldStop(): + return + default: + lt.Events <- interceptMessage_cockroach1462(0) + } + } + }) +} + +func processEventsUntil_cockroach1462(ch <-chan interceptMessage_cockroach1462, stopper *Stopper_cockroach1462) { + for { + select { + case _, ok := <-ch: + runtime.Gosched() + if !ok { + return + } + case <-stopper.ShouldStop(): + return + } + } +} + +func Cockroach1462() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(2000 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i <= 1000; i++ { + go func() { // G1 + stopper := NewStopper_cockroach1462() + transport := NewLocalInterceptableTransport_cockroach1462(stopper).(*localInterceptableTransport_cockroach1462) + stopper.RunWorker(func() { + processEventsUntil_cockroach1462(transport.Events, stopper) + }) + stopper.Stop() + }() + } +} + diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach16167.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach16167.go new file mode 100644 index 00000000000000..4cd14c7a5b3ac5 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach16167.go @@ -0,0 +1,108 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/16167 + * Buggy version: 36fa784aa846b46c29e077634c4e362635f6e74a + * fix commit-id: d064942b067ab84628f79cbfda001fa3138d8d6e + * Flaky: 1/100 + */ + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Cockroach16167", Cockroach16167) +} + +type PreparedStatements_cockroach16167 struct { + session *Session_cockroach16167 +} + +func (ps PreparedStatements_cockroach16167) New(e *Executor_cockroach16167) { + e.Prepare(ps.session) +} + +type Session_cockroach16167 struct { + PreparedStatements PreparedStatements_cockroach16167 +} + +func (s *Session_cockroach16167) resetForBatch(e *Executor_cockroach16167) { + e.getDatabaseCache() +} + +type Executor_cockroach16167 struct { + systemConfigCond *sync.Cond + systemConfigMu sync.RWMutex // L1 +} + +func (e *Executor_cockroach16167) Start() { + e.updateSystemConfig() +} + +func (e *Executor_cockroach16167) execParsed(session *Session_cockroach16167) { + e.systemConfigCond.L.Lock() // Same as e.systemConfigMu.RLock() + runtime.Gosched() + defer e.systemConfigCond.L.Unlock() + runTxnAttempt_cockroach16167(e, session) +} + +func (e *Executor_cockroach16167) execStmtsInCurrentTxn(session *Session_cockroach16167) { + e.execStmtInOpenTxn(session) +} + +func (e *Executor_cockroach16167) execStmtInOpenTxn(session *Session_cockroach16167) { + session.PreparedStatements.New(e) +} + +func (e *Executor_cockroach16167) Prepare(session *Session_cockroach16167) { + session.resetForBatch(e) +} + +func (e *Executor_cockroach16167) getDatabaseCache() { + e.systemConfigMu.RLock() + defer e.systemConfigMu.RUnlock() +} + +func (e *Executor_cockroach16167) updateSystemConfig() { + e.systemConfigMu.Lock() + runtime.Gosched() + defer e.systemConfigMu.Unlock() +} + +func runTxnAttempt_cockroach16167(e *Executor_cockroach16167, session *Session_cockroach16167) { + e.execStmtsInCurrentTxn(session) +} + +func NewExectorAndSession_cockroach16167() (*Executor_cockroach16167, *Session_cockroach16167) { + session := &Session_cockroach16167{} + session.PreparedStatements = PreparedStatements_cockroach16167{session} + e := &Executor_cockroach16167{} + return e, session +} + +func Cockroach16167() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { // G1 + e, s := NewExectorAndSession_cockroach16167() + e.systemConfigCond = sync.NewCond(e.systemConfigMu.RLocker()) + go e.Start() // G2 + e.execParsed(s) + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach18101.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach18101.go new file mode 100644 index 00000000000000..17b03203304ac7 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach18101.go @@ -0,0 +1,60 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/18101 + * Buggy version: f7a8e2f57b6bcf00b9abaf3da00598e4acd3a57f + * fix commit-id: 822bd176cc725c6b50905ea615023200b395e14f + * Flaky: 100/100 + */ + +package main + +import ( + "context" + "os" + "runtime/pprof" + "time" +) + +func init() { + register("Cockroach18101", Cockroach18101) +} + +const chanSize_cockroach18101 = 6 + +func restore_cockroach18101(ctx context.Context) bool { + readyForImportCh := make(chan bool, chanSize_cockroach18101) + go func() { // G2 + defer close(readyForImportCh) + splitAndScatter_cockroach18101(ctx, readyForImportCh) + }() + for readyForImportSpan := range readyForImportCh { + select { + case <-ctx.Done(): + return readyForImportSpan + } + } + return true +} + +func splitAndScatter_cockroach18101(ctx context.Context, readyForImportCh chan bool) { + for i := 0; i < chanSize_cockroach18101+2; i++ { + readyForImportCh <- (false || i != 0) + } +} + +func Cockroach18101() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 100; i++ { + ctx, cancel := context.WithCancel(context.Background()) + go restore_cockroach18101(ctx) // G1 + go cancel() // helper goroutine + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach2448.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach2448.go new file mode 100644 index 00000000000000..a7544bc8a46a18 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach2448.go @@ -0,0 +1,125 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "time" +) + +func init() { + register("Cockroach2448", Cockroach2448) +} + +type Stopper_cockroach2448 struct { + Done chan bool +} + +func (s *Stopper_cockroach2448) ShouldStop() <-chan bool { + return s.Done +} + +type EventMembershipChangeCommitted_cockroach2448 struct { + Callback func() +} + +type MultiRaft_cockroach2448 struct { + stopper *Stopper_cockroach2448 + Events chan interface{} + callbackChan chan func() +} + +// sendEvent can be invoked many times +func (m *MultiRaft_cockroach2448) sendEvent(event interface{}) { + select { + case m.Events <- event: // Waiting for events consumption + case <-m.stopper.ShouldStop(): + } +} + +type state_cockroach2448 struct { + *MultiRaft_cockroach2448 +} + +func (s *state_cockroach2448) start() { + for { + select { + case <-s.stopper.ShouldStop(): + return + case cb := <-s.callbackChan: + cb() + default: + s.handleWriteResponse() + time.Sleep(100 * time.Microsecond) + } + } +} + +func (s *state_cockroach2448) handleWriteResponse() { + s.sendEvent(&EventMembershipChangeCommitted_cockroach2448{ + Callback: func() { + select { + case s.callbackChan <- func() { // Waiting for callbackChan consumption + time.Sleep(time.Nanosecond) + }: + case <-s.stopper.ShouldStop(): + } + }, + }) +} + +type Store_cockroach2448 struct { + multiraft *MultiRaft_cockroach2448 +} + +func (s *Store_cockroach2448) processRaft() { + for { + select { + case e := <-s.multiraft.Events: + switch e := e.(type) { + case *EventMembershipChangeCommitted_cockroach2448: + callback := e.Callback + runtime.Gosched() + if callback != nil { + callback() // Waiting for callbackChan consumption + } + } + case <-s.multiraft.stopper.ShouldStop(): + return + } + } +} + +func NewStoreAndState_cockroach2448() (*Store_cockroach2448, *state_cockroach2448) { + stopper := &Stopper_cockroach2448{ + Done: make(chan bool), + } + mltrft := &MultiRaft_cockroach2448{ + stopper: stopper, + Events: make(chan interface{}), + callbackChan: make(chan func()), + } + st := &state_cockroach2448{mltrft} + s := &Store_cockroach2448{mltrft} + return s, st +} + +func Cockroach2448() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 1000; i++ { + go func() { + s, st := NewStoreAndState_cockroach2448() + go s.processRaft() // G1 + go st.start() // G2 + }() + } +} + diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach24808.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach24808.go new file mode 100644 index 00000000000000..a916d3c928ee2e --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach24808.go @@ -0,0 +1,78 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "context" + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Cockroach24808", Cockroach24808) +} + +type Compactor_cockroach24808 struct { + ch chan struct{} +} + +type Stopper_cockroach24808 struct { + stop sync.WaitGroup + stopper chan struct{} +} + +func (s *Stopper_cockroach24808) RunWorker(ctx context.Context, f func(context.Context)) { + s.stop.Add(1) + go func() { + defer s.stop.Done() + f(ctx) + }() +} + +func (s *Stopper_cockroach24808) ShouldStop() <-chan struct{} { + if s == nil { + return nil + } + return s.stopper +} + +func (s *Stopper_cockroach24808) Stop() { + close(s.stopper) +} + +func (c *Compactor_cockroach24808) Start(ctx context.Context, stopper *Stopper_cockroach24808) { + c.ch <- struct{}{} + stopper.RunWorker(ctx, func(ctx context.Context) { + for { + select { + case <-stopper.ShouldStop(): + return + case <-c.ch: + } + } + }) +} + +func Cockroach24808() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { // G1 + stopper := &Stopper_cockroach24808{stopper: make(chan struct{})} + defer stopper.Stop() + + compactor := &Compactor_cockroach24808{ch: make(chan struct{}, 1)} + compactor.ch <- struct{}{} + + compactor.Start(context.Background(), stopper) + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach25456.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach25456.go new file mode 100644 index 00000000000000..b9259c9f918293 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach25456.go @@ -0,0 +1,92 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" +) + +func init() { + register("Cockroach25456", Cockroach25456) +} + +type Stopper_cockroach25456 struct { + quiescer chan struct{} +} + +func (s *Stopper_cockroach25456) ShouldQuiesce() <-chan struct{} { + if s == nil { + return nil + } + return s.quiescer +} + +func NewStopper_cockroach25456() *Stopper_cockroach25456 { + return &Stopper_cockroach25456{quiescer: make(chan struct{})} +} + +type Store_cockroach25456 struct { + stopper *Stopper_cockroach25456 + consistencyQueue *consistencyQueue_cockroach25456 +} + +func (s *Store_cockroach25456) Stopper() *Stopper_cockroach25456 { + return s.stopper +} + +type Replica_cockroach25456 struct { + store *Store_cockroach25456 +} + +func NewReplica_cockroach25456(store *Store_cockroach25456) *Replica_cockroach25456 { + return &Replica_cockroach25456{store: store} +} + +type consistencyQueue_cockroach25456 struct{} + +func (q *consistencyQueue_cockroach25456) process(repl *Replica_cockroach25456) { + <-repl.store.Stopper().ShouldQuiesce() +} + +func newConsistencyQueue_cockroach25456() *consistencyQueue_cockroach25456 { + return &consistencyQueue_cockroach25456{} +} + +type testContext_cockroach25456 struct { + store *Store_cockroach25456 + repl *Replica_cockroach25456 +} + +func (tc *testContext_cockroach25456) StartWithStoreConfig(stopper *Stopper_cockroach25456) { + if tc.store == nil { + tc.store = &Store_cockroach25456{ + consistencyQueue: newConsistencyQueue_cockroach25456(), + } + } + tc.store.stopper = stopper + tc.repl = NewReplica_cockroach25456(tc.store) +} + +func Cockroach25456() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { // G1 + stopper := NewStopper_cockroach25456() + tc := testContext_cockroach25456{} + tc.StartWithStoreConfig(stopper) + + for i := 0; i < 2; i++ { + tc.store.consistencyQueue.process(tc.repl) + } + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach35073.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach35073.go new file mode 100644 index 00000000000000..f00a7bd46259eb --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach35073.go @@ -0,0 +1,124 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "sync/atomic" +) + +func init() { + register("Cockroach35073", Cockroach35073) +} + +type ConsumerStatus_cockroach35073 uint32 + +const ( + NeedMoreRows_cockroach35073 ConsumerStatus_cockroach35073 = iota + DrainRequested_cockroach35073 + ConsumerClosed_cockroach35073 +) + +const rowChannelBufSize_cockroach35073 = 16 +const outboxBufRows_cockroach35073 = 16 + +type rowSourceBase_cockroach35073 struct { + consumerStatus ConsumerStatus_cockroach35073 +} + +func (rb *rowSourceBase_cockroach35073) consumerClosed() { + atomic.StoreUint32((*uint32)(&rb.consumerStatus), uint32(ConsumerClosed_cockroach35073)) +} + +type RowChannelMsg_cockroach35073 int + +type RowChannel_cockroach35073 struct { + rowSourceBase_cockroach35073 + dataChan chan RowChannelMsg_cockroach35073 +} + +func (rc *RowChannel_cockroach35073) ConsumerClosed() { + rc.consumerClosed() + select { + case <-rc.dataChan: + default: + } +} + +func (rc *RowChannel_cockroach35073) Push() ConsumerStatus_cockroach35073 { + consumerStatus := ConsumerStatus_cockroach35073( + atomic.LoadUint32((*uint32)(&rc.consumerStatus))) + switch consumerStatus { + case NeedMoreRows_cockroach35073: + rc.dataChan <- RowChannelMsg_cockroach35073(0) + case DrainRequested_cockroach35073: + case ConsumerClosed_cockroach35073: + } + return consumerStatus +} + +func (rc *RowChannel_cockroach35073) InitWithNumSenders() { + rc.initWithBufSizeAndNumSenders(rowChannelBufSize_cockroach35073) +} + +func (rc *RowChannel_cockroach35073) initWithBufSizeAndNumSenders(chanBufSize int) { + rc.dataChan = make(chan RowChannelMsg_cockroach35073, chanBufSize) +} + +type outbox_cockroach35073 struct { + RowChannel_cockroach35073 +} + +func (m *outbox_cockroach35073) init() { + m.RowChannel_cockroach35073.InitWithNumSenders() +} + +func (m *outbox_cockroach35073) start(wg *sync.WaitGroup) { + if wg != nil { + wg.Add(1) + } + go m.run(wg) +} + +func (m *outbox_cockroach35073) run(wg *sync.WaitGroup) { + if wg != nil { + wg.Done() + } +} + +func Cockroach35073() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { + outbox := &outbox_cockroach35073{} + outbox.init() + + var wg sync.WaitGroup + for i := 0; i < outboxBufRows_cockroach35073; i++ { + outbox.Push() + } + + var blockedPusherWg sync.WaitGroup + blockedPusherWg.Add(1) + go func() { + outbox.Push() + blockedPusherWg.Done() + }() + + outbox.start(&wg) + + wg.Wait() + outbox.RowChannel_cockroach35073.Push() + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach35931.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach35931.go new file mode 100644 index 00000000000000..9ddcda1b6242bf --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach35931.go @@ -0,0 +1,135 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Cockroach35931", Cockroach35931) +} + +type RowReceiver_cockroach35931 interface { + Push() +} + +type inboundStreamInfo_cockroach35931 struct { + receiver RowReceiver_cockroach35931 +} + +type RowChannel_cockroach35931 struct { + dataChan chan struct{} +} + +func (rc *RowChannel_cockroach35931) Push() { + // The buffer size can be either 0 or 1 when this function is entered. + // We need context sensitivity or a path-condition on the buffer size + // to find this bug. + rc.dataChan <- struct{}{} +} + +func (rc *RowChannel_cockroach35931) initWithBufSizeAndNumSenders(chanBufSize int) { + rc.dataChan = make(chan struct{}, chanBufSize) +} + +type flowEntry_cockroach35931 struct { + flow *Flow_cockroach35931 + inboundStreams map[int]*inboundStreamInfo_cockroach35931 +} + +type flowRegistry_cockroach35931 struct { + sync.Mutex + flows map[int]*flowEntry_cockroach35931 +} + +func (fr *flowRegistry_cockroach35931) getEntryLocked(id int) *flowEntry_cockroach35931 { + entry, ok := fr.flows[id] + if !ok { + entry = &flowEntry_cockroach35931{} + fr.flows[id] = entry + } + return entry +} + +func (fr *flowRegistry_cockroach35931) cancelPendingStreamsLocked(id int) []RowReceiver_cockroach35931 { + entry := fr.flows[id] + pendingReceivers := make([]RowReceiver_cockroach35931, 0) + for _, is := range entry.inboundStreams { + pendingReceivers = append(pendingReceivers, is.receiver) + } + return pendingReceivers +} + +type Flow_cockroach35931 struct { + id int + flowRegistry *flowRegistry_cockroach35931 + inboundStreams map[int]*inboundStreamInfo_cockroach35931 +} + +func (f *Flow_cockroach35931) cancel() { + f.flowRegistry.Lock() + timedOutReceivers := f.flowRegistry.cancelPendingStreamsLocked(f.id) + f.flowRegistry.Unlock() + + for _, receiver := range timedOutReceivers { + receiver.Push() + } +} + +func (fr *flowRegistry_cockroach35931) RegisterFlow(f *Flow_cockroach35931, inboundStreams map[int]*inboundStreamInfo_cockroach35931) { + entry := fr.getEntryLocked(f.id) + entry.flow = f + entry.inboundStreams = inboundStreams +} + +func makeFlowRegistry_cockroach35931() *flowRegistry_cockroach35931 { + return &flowRegistry_cockroach35931{ + flows: make(map[int]*flowEntry_cockroach35931), + } +} + +func Cockroach35931() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { + fr := makeFlowRegistry_cockroach35931() + + left := &RowChannel_cockroach35931{} + left.initWithBufSizeAndNumSenders(1) + right := &RowChannel_cockroach35931{} + right.initWithBufSizeAndNumSenders(1) + + inboundStreams := map[int]*inboundStreamInfo_cockroach35931{ + 0: { + receiver: left, + }, + 1: { + receiver: right, + }, + } + + left.Push() + + flow := &Flow_cockroach35931{ + id: 0, + flowRegistry: fr, + inboundStreams: inboundStreams, + } + + fr.RegisterFlow(flow, inboundStreams) + + flow.cancel() + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach3710.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach3710.go new file mode 100644 index 00000000000000..e419cd2fc32019 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach3710.go @@ -0,0 +1,122 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/3710 + * Buggy version: 4afdd4860fd7c3bd9e92489f84a95e5cc7d11a0d + * fix commit-id: cb65190f9caaf464723e7d072b1f1b69a044ef7b + * Flaky: 2/100 + */ + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" + "unsafe" +) + +func init() { + register("Cockroach3710", Cockroach3710) +} + +type Store_cockroach3710 struct { + raftLogQueue *baseQueue + replicas map[int]*Replica_cockroach3710 + + mu struct { + sync.RWMutex + } +} + +func (s *Store_cockroach3710) ForceRaftLogScanAndProcess() { + s.mu.RLock() + runtime.Gosched() + for _, r := range s.replicas { + s.raftLogQueue.MaybeAdd(r) + } + s.mu.RUnlock() +} + +func (s *Store_cockroach3710) RaftStatus() { + s.mu.RLock() + defer s.mu.RUnlock() +} + +func (s *Store_cockroach3710) processRaft() { + go func() { + for { + var replicas []*Replica_cockroach3710 + s.mu.Lock() + for _, r := range s.replicas { + replicas = append(replicas, r) + } + s.mu.Unlock() + break + } + }() +} + +type Replica_cockroach3710 struct { + store *Store_cockroach3710 +} + +type baseQueue struct { + sync.Mutex + impl *raftLogQueue +} + +func (bq *baseQueue) MaybeAdd(repl *Replica_cockroach3710) { + bq.Lock() + defer bq.Unlock() + bq.impl.shouldQueue(repl) +} + +type raftLogQueue struct{} + +func (*raftLogQueue) shouldQueue(r *Replica_cockroach3710) { + getTruncatableIndexes(r) +} + +func getTruncatableIndexes(r *Replica_cockroach3710) { + r.store.RaftStatus() +} + +func NewStore_cockroach3710() *Store_cockroach3710 { + rlq := &raftLogQueue{} + bq := &baseQueue{impl: rlq} + store := &Store_cockroach3710{ + raftLogQueue: bq, + replicas: make(map[int]*Replica_cockroach3710), + } + r1 := &Replica_cockroach3710{store} + r2 := &Replica_cockroach3710{store} + + makeKey := func(r *Replica_cockroach3710) int { + return int((uintptr(unsafe.Pointer(r)) >> 1) % 7) + } + store.replicas[makeKey(r1)] = r1 + store.replicas[makeKey(r2)] = r2 + + return store +} + +func Cockroach3710() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 10000; i++ { + go func() { + store := NewStore_cockroach3710() + go store.ForceRaftLogScanAndProcess() // G1 + go store.processRaft() // G2 + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach584.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach584.go new file mode 100644 index 00000000000000..33f7ba7a45ec9a --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach584.go @@ -0,0 +1,62 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Cockroach584", Cockroach584) +} + +type gossip_cockroach584 struct { + mu sync.Mutex // L1 + closed bool +} + +func (g *gossip_cockroach584) bootstrap() { + for { + g.mu.Lock() + if g.closed { + // Missing g.mu.Unlock + break + } + g.mu.Unlock() + } +} + +func (g *gossip_cockroach584) manage() { + for { + g.mu.Lock() + if g.closed { + // Missing g.mu.Unlock + break + } + g.mu.Unlock() + } +} + +func Cockroach584() { + prof := pprof.Lookup("goroutineleak") + defer func() { + for i := 0; i < yieldCount; i++ { + // Yield several times to allow the child goroutine to run. + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + g := &gossip_cockroach584{ + closed: true, + } + go func() { // G1 + g.bootstrap() + g.manage() + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach6181.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach6181.go new file mode 100644 index 00000000000000..80f1dd504daae5 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach6181.go @@ -0,0 +1,87 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/6181 + * Buggy version: c0a232b5521565904b851699853bdbd0c670cf1e + * fix commit-id: d5814e4886a776bf7789b3c51b31f5206480d184 + * Flaky: 57/100 + */ +package main + +import ( + "io" + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Cockroach6181", Cockroach6181) +} + +type testDescriptorDB_cockroach6181 struct { + cache *rangeDescriptorCache_cockroach6181 +} + +func initTestDescriptorDB_cockroach6181() *testDescriptorDB_cockroach6181 { + return &testDescriptorDB_cockroach6181{&rangeDescriptorCache_cockroach6181{}} +} + +type rangeDescriptorCache_cockroach6181 struct { + rangeCacheMu sync.RWMutex +} + +func (rdc *rangeDescriptorCache_cockroach6181) LookupRangeDescriptor() { + rdc.rangeCacheMu.RLock() + runtime.Gosched() + io.Discard.Write([]byte(rdc.String())) + rdc.rangeCacheMu.RUnlock() + rdc.rangeCacheMu.Lock() + rdc.rangeCacheMu.Unlock() +} + +func (rdc *rangeDescriptorCache_cockroach6181) String() string { + rdc.rangeCacheMu.RLock() + defer rdc.rangeCacheMu.RUnlock() + return rdc.stringLocked() +} + +func (rdc *rangeDescriptorCache_cockroach6181) stringLocked() string { + return "something here" +} + +func doLookupWithToken_cockroach6181(rc *rangeDescriptorCache_cockroach6181) { + rc.LookupRangeDescriptor() +} + +func testRangeCacheCoalescedRequests_cockroach6181() { + db := initTestDescriptorDB_cockroach6181() + pauseLookupResumeAndAssert := func() { + var wg sync.WaitGroup + for i := 0; i < 3; i++ { + wg.Add(1) + go func() { // G2,G3,... + doLookupWithToken_cockroach6181(db.cache) + wg.Done() + }() + } + wg.Wait() + } + pauseLookupResumeAndAssert() +} + +func Cockroach6181() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 100; i++ { + go testRangeCacheCoalescedRequests_cockroach6181() // G1 + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach7504.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach7504.go new file mode 100644 index 00000000000000..945308a76f92b1 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach7504.go @@ -0,0 +1,183 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/7504 + * Buggy version: bc963b438cdc3e0ad058a5282358e5aee0595e17 + * fix commit-id: cab761b9f5ee5dee1448bc5d6b1d9f5a0ff0bad5 + * Flaky: 1/100 + */ +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Cockroach7504", Cockroach7504) +} + +func MakeCacheKey_cockroach7504(lease *LeaseState_cockroach7504) int { + return lease.id +} + +type LeaseState_cockroach7504 struct { + mu sync.Mutex // L1 + id int +} +type LeaseSet_cockroach7504 struct { + data []*LeaseState_cockroach7504 +} + +func (l *LeaseSet_cockroach7504) find(id int) *LeaseState_cockroach7504 { + return l.data[id] +} + +func (l *LeaseSet_cockroach7504) remove(s *LeaseState_cockroach7504) { + for i := 0; i < len(l.data); i++ { + if s == l.data[i] { + l.data = append(l.data[:i], l.data[i+1:]...) + break + } + } +} + +type tableState_cockroach7504 struct { + tableNameCache *tableNameCache_cockroach7504 + mu sync.Mutex // L3 + active *LeaseSet_cockroach7504 +} + +func (t *tableState_cockroach7504) release(lease *LeaseState_cockroach7504) { + t.mu.Lock() // L3 + defer t.mu.Unlock() // L3 + + s := t.active.find(MakeCacheKey_cockroach7504(lease)) + s.mu.Lock() // L1 + runtime.Gosched() + defer s.mu.Unlock() // L1 + + t.removeLease(s) +} +func (t *tableState_cockroach7504) removeLease(lease *LeaseState_cockroach7504) { + t.active.remove(lease) + t.tableNameCache.remove(lease) // L1 acquire/release +} + +type tableNameCache_cockroach7504 struct { + mu sync.Mutex // L2 + tables map[int]*LeaseState_cockroach7504 +} + +func (c *tableNameCache_cockroach7504) get(id int) { + c.mu.Lock() // L2 + defer c.mu.Unlock() // L2 + lease, ok := c.tables[id] + if !ok { + return + } + if lease == nil { + panic("nil lease in name cache") + } + lease.mu.Lock() // L1 + defer lease.mu.Unlock() // L1 +} + +func (c *tableNameCache_cockroach7504) remove(lease *LeaseState_cockroach7504) { + c.mu.Lock() // L2 + runtime.Gosched() + defer c.mu.Unlock() // L2 + key := MakeCacheKey_cockroach7504(lease) + existing, ok := c.tables[key] + if !ok { + return + } + if existing == lease { + delete(c.tables, key) + } +} + +type LeaseManager_cockroach7504 struct { + _ [64]byte + tableNames *tableNameCache_cockroach7504 + tables map[int]*tableState_cockroach7504 +} + +func (m *LeaseManager_cockroach7504) AcquireByName(id int) { + m.tableNames.get(id) +} + +func (m *LeaseManager_cockroach7504) findTableState(lease *LeaseState_cockroach7504) *tableState_cockroach7504 { + existing, ok := m.tables[lease.id] + if !ok { + return nil + } + return existing +} + +func (m *LeaseManager_cockroach7504) Release(lease *LeaseState_cockroach7504) { + t := m.findTableState(lease) + t.release(lease) +} +func NewLeaseManager_cockroach7504(tname *tableNameCache_cockroach7504, ts *tableState_cockroach7504) *LeaseManager_cockroach7504 { + mgr := &LeaseManager_cockroach7504{ + tableNames: tname, + tables: make(map[int]*tableState_cockroach7504), + } + mgr.tables[0] = ts + return mgr +} +func NewLeaseSet_cockroach7504(n int) *LeaseSet_cockroach7504 { + lset := &LeaseSet_cockroach7504{} + for i := 0; i < n; i++ { + lease := new(LeaseState_cockroach7504) + lset.data = append(lset.data, lease) + } + return lset +} + +func Cockroach7504() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 100; i++ { + go func() { + leaseNum := 2 + lset := NewLeaseSet_cockroach7504(leaseNum) + + nc := &tableNameCache_cockroach7504{ + tables: make(map[int]*LeaseState_cockroach7504), + } + for i := 0; i < leaseNum; i++ { + nc.tables[i] = lset.find(i) + } + + ts := &tableState_cockroach7504{ + tableNameCache: nc, + active: lset, + } + + mgr := NewLeaseManager_cockroach7504(nc, ts) + + // G1 + go func() { + // lock L2-L1 + mgr.AcquireByName(0) + }() + + // G2 + go func() { + // lock L1-L2 + mgr.Release(lset.find(0)) + }() + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach9935.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach9935.go new file mode 100644 index 00000000000000..e143a6670d8ff2 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach9935.go @@ -0,0 +1,77 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: cockroach + * Issue or PR : https://github.com/cockroachdb/cockroach/pull/9935 + * Buggy version: 4df302cc3f03328395dc3fefbfba58b7718e4f2f + * fix commit-id: ed6a100ba38dd51b0888b9a3d3ac6bdbb26c528c + * Flaky: 100/100 + * Description: This leak is caused by acquiring l.mu.Lock() twice. The fix is + * to release l.mu.Lock() before acquiring l.mu.Lock for the second time. + */ +package main + +import ( + "errors" + "math/rand" + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Cockroach9935", Cockroach9935) +} + +type loggingT_cockroach9935 struct { + mu sync.Mutex +} + +func (l *loggingT_cockroach9935) outputLogEntry() { + l.mu.Lock() + if err := l.createFile(); err != nil { + l.exit(err) + } + l.mu.Unlock() +} + +func (l *loggingT_cockroach9935) createFile() error { + if rand.Intn(8)%4 > 0 { + return errors.New("") + } + return nil +} + +func (l *loggingT_cockroach9935) exit(err error) { + l.mu.Lock() // Blocked forever + defer l.mu.Unlock() +} + +// Example of goroutine leak trace: +// +// G1 +//---------------------------- +// l.outputLogEntry() +// l.mu.Lock() +// l.createFile() +// l.exit() +// l.mu.Lock() +//-----------G1 leaks--------- + +func Cockroach9935() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + l := &loggingT_cockroach9935{} + go l.outputLogEntry() // G1 + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/etcd10492.go b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd10492.go new file mode 100644 index 00000000000000..7d56642d5e9ed9 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd10492.go @@ -0,0 +1,72 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "context" + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Etcd10492", Etcd10492) +} + +type Checkpointer_etcd10492 func(ctx context.Context) + +type lessor_etcd10492 struct { + mu sync.RWMutex + cp Checkpointer_etcd10492 + checkpointInterval time.Duration +} + +func (le *lessor_etcd10492) Checkpoint() { + le.mu.Lock() // Lock acquired twice here + defer le.mu.Unlock() +} + +func (le *lessor_etcd10492) SetCheckpointer(cp Checkpointer_etcd10492) { + le.mu.Lock() + defer le.mu.Unlock() + + le.cp = cp +} + +func (le *lessor_etcd10492) Renew() { + le.mu.Lock() + unlock := func() { le.mu.Unlock() } + defer func() { unlock() }() + + if le.cp != nil { + le.cp(context.Background()) + } +} + +func Etcd10492() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + go func() { // G1 + le := &lessor_etcd10492{ + checkpointInterval: 0, + } + fakerCheckerpointer_etcd10492 := func(ctx context.Context) { + le.Checkpoint() + } + le.SetCheckpointer(fakerCheckerpointer_etcd10492) + le.mu.Lock() + le.mu.Unlock() + le.Renew() + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/etcd5509.go b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd5509.go new file mode 100644 index 00000000000000..868e926e66949a --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd5509.go @@ -0,0 +1,126 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "context" + "io" + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Etcd5509", Etcd5509) +} + +var ErrConnClosed_etcd5509 error + +type Client_etcd5509 struct { + mu sync.RWMutex + ctx context.Context + cancel context.CancelFunc +} + +func (c *Client_etcd5509) Close() { + c.mu.Lock() + defer c.mu.Unlock() + if c.cancel == nil { + return + } + c.cancel() + c.cancel = nil + c.mu.Unlock() + c.mu.Lock() +} + +type remoteClient_etcd5509 struct { + client *Client_etcd5509 + mu sync.Mutex +} + +func (r *remoteClient_etcd5509) acquire(ctx context.Context) error { + for { + r.client.mu.RLock() + closed := r.client.cancel == nil + r.mu.Lock() + r.mu.Unlock() + if closed { + return ErrConnClosed_etcd5509 // Missing RUnlock before return + } + r.client.mu.RUnlock() + } +} + +type kv_etcd5509 struct { + rc *remoteClient_etcd5509 +} + +func (kv *kv_etcd5509) Get(ctx context.Context) error { + return kv.Do(ctx) +} + +func (kv *kv_etcd5509) Do(ctx context.Context) error { + for { + err := kv.do(ctx) + if err == nil { + return nil + } + return err + } +} + +func (kv *kv_etcd5509) do(ctx context.Context) error { + err := kv.getRemote(ctx) + return err +} + +func (kv *kv_etcd5509) getRemote(ctx context.Context) error { + return kv.rc.acquire(ctx) +} + +type KV interface { + Get(ctx context.Context) error + Do(ctx context.Context) error +} + +func NewKV_etcd5509(c *Client_etcd5509) KV { + return &kv_etcd5509{rc: &remoteClient_etcd5509{ + client: c, + }} +} + +func Etcd5509() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + go func() { + ctx, _ := context.WithCancel(context.TODO()) + cli := &Client_etcd5509{ + ctx: ctx, + } + kv := NewKV_etcd5509(cli) + donec := make(chan struct{}) + go func() { + defer close(donec) + err := kv.Get(context.TODO()) + if err != nil && err != ErrConnClosed_etcd5509 { + io.Discard.Write([]byte("Expect ErrConnClosed")) + } + }() + + runtime.Gosched() + cli.Close() + + <-donec + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6708.go b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6708.go new file mode 100644 index 00000000000000..afbbe35104bbb8 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6708.go @@ -0,0 +1,100 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "context" + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Etcd6708", Etcd6708) +} + +type EndpointSelectionMode_etcd6708 int + +const ( + EndpointSelectionRandom_etcd6708 EndpointSelectionMode_etcd6708 = iota + EndpointSelectionPrioritizeLeader_etcd6708 +) + +type MembersAPI_etcd6708 interface { + Leader(ctx context.Context) +} + +type Client_etcd6708 interface { + Sync(ctx context.Context) + SetEndpoints() + httpClient_etcd6708 +} + +type httpClient_etcd6708 interface { + Do(context.Context) +} + +type httpClusterClient_etcd6708 struct { + sync.RWMutex + selectionMode EndpointSelectionMode_etcd6708 +} + +func (c *httpClusterClient_etcd6708) getLeaderEndpoint() { + mAPI := NewMembersAPI_etcd6708(c) + mAPI.Leader(context.Background()) +} + +func (c *httpClusterClient_etcd6708) SetEndpoints() { + switch c.selectionMode { + case EndpointSelectionRandom_etcd6708: + case EndpointSelectionPrioritizeLeader_etcd6708: + c.getLeaderEndpoint() + } +} + +func (c *httpClusterClient_etcd6708) Do(ctx context.Context) { + c.RLock() + c.RUnlock() +} + +func (c *httpClusterClient_etcd6708) Sync(ctx context.Context) { + c.Lock() + defer c.Unlock() + + c.SetEndpoints() +} + +type httpMembersAPI_etcd6708 struct { + client httpClient_etcd6708 +} + +func (m *httpMembersAPI_etcd6708) Leader(ctx context.Context) { + m.client.Do(ctx) +} + +func NewMembersAPI_etcd6708(c Client_etcd6708) MembersAPI_etcd6708 { + return &httpMembersAPI_etcd6708{ + client: c, + } +} + +func Etcd6708() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + go func() { + hc := &httpClusterClient_etcd6708{ + selectionMode: EndpointSelectionPrioritizeLeader_etcd6708, + } + hc.Sync(context.Background()) + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6857.go b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6857.go new file mode 100644 index 00000000000000..0798ab23d3b588 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6857.go @@ -0,0 +1,81 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: etcd + * Issue or PR : https://github.com/etcd-io/etcd/pull/6857 + * Buggy version: 7c8f13aed7fe251e7066ed6fc1a090699c2cae0e + * fix commit-id: 7afc490c95789c408fbc256d8e790273d331c984 + * Flaky: 19/100 + */ +package main + +import ( + "os" + "runtime/pprof" + "time" +) + +func init() { + register("Etcd6857", Etcd6857) +} + +type Status_etcd6857 struct{} + +type node_etcd6857 struct { + status chan chan Status_etcd6857 + stop chan struct{} + done chan struct{} +} + +func (n *node_etcd6857) Status() Status_etcd6857 { + c := make(chan Status_etcd6857) + n.status <- c + return <-c +} + +func (n *node_etcd6857) run() { + for { + select { + case c := <-n.status: + c <- Status_etcd6857{} + case <-n.stop: + close(n.done) + return + } + } +} + +func (n *node_etcd6857) Stop() { + select { + case n.stop <- struct{}{}: + case <-n.done: + return + } + <-n.done +} + +func NewNode_etcd6857() *node_etcd6857 { + return &node_etcd6857{ + status: make(chan chan Status_etcd6857), + stop: make(chan struct{}), + done: make(chan struct{}), + } +} + +func Etcd6857() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i <= 100; i++ { + go func() { + n := NewNode_etcd6857() + go n.run() // G1 + go n.Status() // G2 + go n.Stop() // G3 + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6873.go b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6873.go new file mode 100644 index 00000000000000..1846d0f260c2f6 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd6873.go @@ -0,0 +1,98 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: etcd + * Issue or PR : https://github.com/etcd-io/etcd/commit/7618fdd1d642e47cac70c03f637b0fd798a53a6e + * Buggy version: 377f19b0031f9c0aafe2aec28b6f9019311f52f9 + * fix commit-id: 7618fdd1d642e47cac70c03f637b0fd798a53a6e + * Flaky: 9/100 + */ +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Etcd6873", Etcd6873) +} + +type watchBroadcast_etcd6873 struct{} + +type watchBroadcasts_etcd6873 struct { + mu sync.Mutex + updatec chan *watchBroadcast_etcd6873 + donec chan struct{} +} + +func newWatchBroadcasts_etcd6873() *watchBroadcasts_etcd6873 { + wbs := &watchBroadcasts_etcd6873{ + updatec: make(chan *watchBroadcast_etcd6873, 1), + donec: make(chan struct{}), + } + go func() { // G2 + defer close(wbs.donec) + for wb := range wbs.updatec { + wbs.coalesce(wb) + } + }() + return wbs +} + +func (wbs *watchBroadcasts_etcd6873) coalesce(wb *watchBroadcast_etcd6873) { + wbs.mu.Lock() + wbs.mu.Unlock() +} + +func (wbs *watchBroadcasts_etcd6873) stop() { + wbs.mu.Lock() + defer wbs.mu.Unlock() + close(wbs.updatec) + <-wbs.donec +} + +func (wbs *watchBroadcasts_etcd6873) update(wb *watchBroadcast_etcd6873) { + select { + case wbs.updatec <- wb: + default: + } +} + +// Example of goroutine leak trace: +// +// G1 G2 G3 +//--------------------------------------------------------- +// newWatchBroadcasts() +// wbs.update() +// wbs.updatec <- +// return +// <-wbs.updatec +// wbs.coalesce() +// wbs.stop() +// wbs.mu.Lock() +// close(wbs.updatec) +// <-wbs.donec +// wbs.mu.Lock() +//---------------------G2,G3 leak------------------------- +// + +func Etcd6873() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + wbs := newWatchBroadcasts_etcd6873() // G1 + wbs.update(&watchBroadcast_etcd6873{}) + go wbs.stop() // G3 + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/etcd7492.go b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd7492.go new file mode 100644 index 00000000000000..3c8d58a221cac5 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd7492.go @@ -0,0 +1,163 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: etcd + * Issue or PR : https://github.com/etcd-io/etcd/pull/7492 + * Buggy version: 51939650057d602bb5ab090633138fffe36854dc + * fix commit-id: 1b1fabef8ffec606909f01c3983300fff539f214 + * Flaky: 40/100 + */ +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Etcd7492", Etcd7492) +} + +type TokenProvider_etcd7492 interface { + assign() + enable() + disable() +} + +type simpleTokenTTLKeeper_etcd7492 struct { + tokens map[string]time.Time + addSimpleTokenCh chan struct{} + stopCh chan chan struct{} + deleteTokenFunc func(string) +} + +type authStore_etcd7492 struct { + tokenProvider TokenProvider_etcd7492 +} + +func (as *authStore_etcd7492) Authenticate() { + as.tokenProvider.assign() +} + +func NewSimpleTokenTTLKeeper_etcd7492(deletefunc func(string)) *simpleTokenTTLKeeper_etcd7492 { + stk := &simpleTokenTTLKeeper_etcd7492{ + tokens: make(map[string]time.Time), + addSimpleTokenCh: make(chan struct{}, 1), + stopCh: make(chan chan struct{}), + deleteTokenFunc: deletefunc, + } + go stk.run() // G1 + return stk +} + +func (tm *simpleTokenTTLKeeper_etcd7492) run() { + tokenTicker := time.NewTicker(time.Nanosecond) + defer tokenTicker.Stop() + for { + select { + case <-tm.addSimpleTokenCh: + runtime.Gosched() + /// Make tm.tokens not empty is enough + tm.tokens["1"] = time.Now() + case <-tokenTicker.C: + runtime.Gosched() + for t, _ := range tm.tokens { + tm.deleteTokenFunc(t) + delete(tm.tokens, t) + } + case waitCh := <-tm.stopCh: + waitCh <- struct{}{} + return + } + } +} + +func (tm *simpleTokenTTLKeeper_etcd7492) addSimpleToken() { + tm.addSimpleTokenCh <- struct{}{} + runtime.Gosched() +} + +func (tm *simpleTokenTTLKeeper_etcd7492) stop() { + waitCh := make(chan struct{}) + tm.stopCh <- waitCh + <-waitCh + close(tm.stopCh) +} + +type tokenSimple_etcd7492 struct { + simpleTokenKeeper *simpleTokenTTLKeeper_etcd7492 + simpleTokensMu sync.RWMutex +} + +func (t *tokenSimple_etcd7492) assign() { + t.assignSimpleTokenToUser() +} + +func (t *tokenSimple_etcd7492) assignSimpleTokenToUser() { + t.simpleTokensMu.Lock() + runtime.Gosched() + t.simpleTokenKeeper.addSimpleToken() + t.simpleTokensMu.Unlock() +} +func newDeleterFunc(t *tokenSimple_etcd7492) func(string) { + return func(tk string) { + t.simpleTokensMu.Lock() + defer t.simpleTokensMu.Unlock() + } +} + +func (t *tokenSimple_etcd7492) enable() { + t.simpleTokenKeeper = NewSimpleTokenTTLKeeper_etcd7492(newDeleterFunc(t)) +} + +func (t *tokenSimple_etcd7492) disable() { + if t.simpleTokenKeeper != nil { + t.simpleTokenKeeper.stop() + t.simpleTokenKeeper = nil + } + t.simpleTokensMu.Lock() + t.simpleTokensMu.Unlock() +} + +func newTokenProviderSimple_etcd7492() *tokenSimple_etcd7492 { + return &tokenSimple_etcd7492{} +} + +func setupAuthStore_etcd7492() (store *authStore_etcd7492, teardownfunc func()) { + as := &authStore_etcd7492{ + tokenProvider: newTokenProviderSimple_etcd7492(), + } + as.tokenProvider.enable() + tearDown := func() { + as.tokenProvider.disable() + } + return as, tearDown +} + +func Etcd7492() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 100; i++ { + go func() { + as, tearDown := setupAuthStore_etcd7492() + defer tearDown() + var wg sync.WaitGroup + wg.Add(3) + for i := 0; i < 3; i++ { + go func() { // G2 + as.Authenticate() + defer wg.Done() + }() + } + wg.Wait() + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/etcd7902.go b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd7902.go new file mode 100644 index 00000000000000..0a96d7f0472d9e --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/etcd7902.go @@ -0,0 +1,87 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: etcd + * Issue or PR : https://github.com/coreos/etcd/pull/7902 + * Buggy version: dfdaf082c51ba14861267f632f6af795a27eb4ef + * fix commit-id: 87d99fe0387ee1df1cf1811d88d37331939ef4ae + * Flaky: 100/100 + */ +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Etcd7902", Etcd7902) +} + +type roundClient_etcd7902 struct { + progress int + acquire func() + validate func() + release func() +} + +func runElectionFunc_etcd7902() { + rcs := make([]roundClient_etcd7902, 3) + nextc := make(chan bool) + for i := range rcs { + var rcNextc chan bool + setRcNextc := func() { + rcNextc = nextc + } + rcs[i].acquire = func() {} + rcs[i].validate = func() { + setRcNextc() + } + rcs[i].release = func() { + if i == 0 { // Assume the first roundClient is the leader + close(nextc) + nextc = make(chan bool) + } + <-rcNextc // Follower is blocking here + } + } + doRounds_etcd7902(rcs, 100) +} + +func doRounds_etcd7902(rcs []roundClient_etcd7902, rounds int) { + var mu sync.Mutex + var wg sync.WaitGroup + wg.Add(len(rcs)) + for i := range rcs { + go func(rc *roundClient_etcd7902) { // G2,G3 + defer wg.Done() + for rc.progress < rounds || rounds <= 0 { + rc.acquire() + mu.Lock() + rc.validate() + mu.Unlock() + time.Sleep(10 * time.Millisecond) + rc.progress++ + mu.Lock() + rc.release() + mu.Unlock() + } + }(&rcs[i]) + } + wg.Wait() +} + +func Etcd7902() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 100; i++ { + go runElectionFunc_etcd7902() // G1 + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1275.go b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1275.go new file mode 100644 index 00000000000000..ec5491e438f74a --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1275.go @@ -0,0 +1,111 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: grpc-go + * Issue or PR : https://github.com/grpc/grpc-go/pull/1275 + * Buggy version: (missing) + * fix commit-id: 0669f3f89e0330e94bb13fa1ce8cc704aab50c9c + * Flaky: 100/100 + */ +package main + +import ( + "io" + "os" + "runtime/pprof" + "time" +) + +func init() { + register("Grpc1275", Grpc1275) +} + +type recvBuffer_grpc1275 struct { + c chan bool +} + +func (b *recvBuffer_grpc1275) get() <-chan bool { + return b.c +} + +type recvBufferReader_grpc1275 struct { + recv *recvBuffer_grpc1275 +} + +func (r *recvBufferReader_grpc1275) Read(p []byte) (int, error) { + select { + case <-r.recv.get(): + } + return 0, nil +} + +type Stream_grpc1275 struct { + trReader io.Reader +} + +func (s *Stream_grpc1275) Read(p []byte) (int, error) { + return io.ReadFull(s.trReader, p) +} + +type http2Client_grpc1275 struct{} + +func (t *http2Client_grpc1275) CloseStream(s *Stream_grpc1275) { + // It is the client.CloseSream() method called by the + // main goroutine that should send the message, but it + // is not. The patch is to send out this message. +} + +func (t *http2Client_grpc1275) NewStream() *Stream_grpc1275 { + return &Stream_grpc1275{ + trReader: &recvBufferReader_grpc1275{ + recv: &recvBuffer_grpc1275{ + c: make(chan bool), + }, + }, + } +} + +func testInflightStreamClosing_grpc1275() { + client := &http2Client_grpc1275{} + stream := client.NewStream() + donec := make(chan bool) + go func() { // G2 + defer close(donec) + stream.Read([]byte{1}) + }() + + client.CloseStream(stream) + + timeout := time.NewTimer(300 * time.Nanosecond) + select { + case <-donec: + if !timeout.Stop() { + <-timeout.C + } + case <-timeout.C: + } +} + +/// +/// G1 G2 +/// testInflightStreamClosing() +/// stream.Read() +/// io.ReadFull() +/// <- r.recv.get() +/// CloseStream() +/// <- donec +/// ------------G1 timeout, G2 leak--------------------- +/// + +func Grpc1275() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + go func() { + testInflightStreamClosing_grpc1275() // G1 + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1424.go b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1424.go new file mode 100644 index 00000000000000..777534a788163c --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1424.go @@ -0,0 +1,105 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: grpc-go + * Issue or PR : https://github.com/grpc/grpc-go/pull/1424 + * Buggy version: 39c8c3866d926d95e11c03508bf83d00f2963f91 + * fix commit-id: 64bd0b04a7bb1982078bae6a2ab34c226125fbc1 + * Flaky: 100/100 + */ +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Grpc1424", Grpc1424) +} + +type Balancer_grpc1424 interface { + Notify() <-chan bool +} + +type roundRobin_grpc1424 struct { + mu sync.Mutex + addrCh chan bool +} + +func (rr *roundRobin_grpc1424) Notify() <-chan bool { + return rr.addrCh +} + +type addrConn_grpc1424 struct { + mu sync.Mutex +} + +func (ac *addrConn_grpc1424) tearDown() { + ac.mu.Lock() + defer ac.mu.Unlock() +} + +type dialOption_grpc1424 struct { + balancer Balancer_grpc1424 +} + +type ClientConn_grpc1424 struct { + dopts dialOption_grpc1424 + conns []*addrConn_grpc1424 +} + +func (cc *ClientConn_grpc1424) lbWatcher(doneChan chan bool) { + for addr := range cc.dopts.balancer.Notify() { + if addr { + // nop, make compiler happy + } + var ( + del []*addrConn_grpc1424 + ) + for _, a := range cc.conns { + del = append(del, a) + } + for _, c := range del { + c.tearDown() + } + } +} + +func NewClientConn_grpc1424() *ClientConn_grpc1424 { + cc := &ClientConn_grpc1424{ + dopts: dialOption_grpc1424{ + &roundRobin_grpc1424{addrCh: make(chan bool)}, + }, + } + return cc +} + +func DialContext_grpc1424() { + cc := NewClientConn_grpc1424() + waitC := make(chan error, 1) + go func() { // G2 + defer close(waitC) + ch := cc.dopts.balancer.Notify() + if ch != nil { + doneChan := make(chan bool) + go cc.lbWatcher(doneChan) // G3 + <-doneChan + } + }() + /// close addrCh + close(cc.dopts.balancer.(*roundRobin_grpc1424).addrCh) +} + +func Grpc1424() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + go DialContext_grpc1424() // G1 +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1460.go b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1460.go new file mode 100644 index 00000000000000..bc658b408d8c6b --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc1460.go @@ -0,0 +1,84 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: grpc + * Issue or PR : https://github.com/grpc/grpc-go/pull/1460 + * Buggy version: 7db1564ba1229bc42919bb1f6d9c4186f3aa8678 + * fix commit-id: e605a1ecf24b634f94f4eefdab10a9ada98b70dd + * Flaky: 100/100 + */ +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Grpc1460", Grpc1460) +} + +type Stream_grpc1460 struct{} + +type http2Client_grpc1460 struct { + mu sync.Mutex + awakenKeepalive chan struct{} + activeStream []*Stream_grpc1460 +} + +func (t *http2Client_grpc1460) keepalive() { + t.mu.Lock() + if len(t.activeStream) < 1 { + <-t.awakenKeepalive + runtime.Gosched() + t.mu.Unlock() + } else { + t.mu.Unlock() + } +} + +func (t *http2Client_grpc1460) NewStream() { + t.mu.Lock() + runtime.Gosched() + t.activeStream = append(t.activeStream, &Stream_grpc1460{}) + if len(t.activeStream) == 1 { + select { + case t.awakenKeepalive <- struct{}{}: + default: + } + } + t.mu.Unlock() +} + +/// +/// G1 G2 +/// client.keepalive() +/// client.NewStream() +/// t.mu.Lock() +/// <-t.awakenKeepalive +/// t.mu.Lock() +/// ---------------G1, G2 deadlock-------------- +/// + +func Grpc1460() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 1000; i++ { + go func() { + client := &http2Client_grpc1460{ + awakenKeepalive: make(chan struct{}), + } + go client.keepalive() //G1 + go client.NewStream() //G2 + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/grpc3017.go b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc3017.go new file mode 100644 index 00000000000000..0523b9509fdcbe --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc3017.go @@ -0,0 +1,123 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +// This test case is a reproduction of grpc/3017. +// +// It is a goroutine leak that also simultaneously engages many GC assists. +// Testing runtime behaviour when pivoting between regular and goroutine leak detection modes. + +func init() { + register("Grpc3017", Grpc3017) +} + +type Address_grpc3017 int +type SubConn_grpc3017 int + +type subConnCacheEntry_grpc3017 struct { + sc SubConn_grpc3017 + cancel func() + abortDeleting bool +} + +type lbCacheClientConn_grpc3017 struct { + mu sync.Mutex // L1 + timeout time.Duration + subConnCache map[Address_grpc3017]*subConnCacheEntry_grpc3017 + subConnToAddr map[SubConn_grpc3017]Address_grpc3017 +} + +func (ccc *lbCacheClientConn_grpc3017) NewSubConn(addrs []Address_grpc3017) SubConn_grpc3017 { + if len(addrs) != 1 { + return SubConn_grpc3017(1) + } + addrWithoutMD := addrs[0] + ccc.mu.Lock() // L1 + defer ccc.mu.Unlock() + if entry, ok := ccc.subConnCache[addrWithoutMD]; ok { + entry.cancel() + delete(ccc.subConnCache, addrWithoutMD) + return entry.sc + } + scNew := SubConn_grpc3017(1) + ccc.subConnToAddr[scNew] = addrWithoutMD + return scNew +} + +func (ccc *lbCacheClientConn_grpc3017) RemoveSubConn(sc SubConn_grpc3017) { + ccc.mu.Lock() // L1 + defer ccc.mu.Unlock() + addr, ok := ccc.subConnToAddr[sc] + if !ok { + return + } + + if entry, ok := ccc.subConnCache[addr]; ok { + if entry.sc != sc { + delete(ccc.subConnToAddr, sc) + } + return + } + + entry := &subConnCacheEntry_grpc3017{ + sc: sc, + } + ccc.subConnCache[addr] = entry + + timer := time.AfterFunc(ccc.timeout, func() { // G3 + runtime.Gosched() + ccc.mu.Lock() // L1 + if entry.abortDeleting { + return // Missing unlock + } + delete(ccc.subConnToAddr, sc) + delete(ccc.subConnCache, addr) + ccc.mu.Unlock() + }) + + entry.cancel = func() { + if !timer.Stop() { + entry.abortDeleting = true + } + } +} + +func Grpc3017() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { //G1 + done := make(chan struct{}) + + ccc := &lbCacheClientConn_grpc3017{ + timeout: time.Nanosecond, + subConnCache: make(map[Address_grpc3017]*subConnCacheEntry_grpc3017), + subConnToAddr: make(map[SubConn_grpc3017]Address_grpc3017), + } + + sc := ccc.NewSubConn([]Address_grpc3017{Address_grpc3017(1)}) + go func() { // G2 + for i := 0; i < 10000; i++ { + ccc.RemoveSubConn(sc) + sc = ccc.NewSubConn([]Address_grpc3017{Address_grpc3017(1)}) + } + close(done) + }() + <-done + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/grpc660.go b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc660.go new file mode 100644 index 00000000000000..5f6201ec8062d9 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc660.go @@ -0,0 +1,65 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: grpc-go + * Issue or PR : https://github.com/grpc/grpc-go/pull/660 + * Buggy version: db85417dd0de6cc6f583672c6175a7237e5b5dd2 + * fix commit-id: ceacfbcbc1514e4e677932fd55938ac455d182fb + * Flaky: 100/100 + */ +package main + +import ( + "math/rand" + "os" + "runtime" + "runtime/pprof" +) + +func init() { + register("Grpc660", Grpc660) +} + +type benchmarkClient_grpc660 struct { + stop chan bool +} + +func (bc *benchmarkClient_grpc660) doCloseLoopUnary() { + for { + done := make(chan bool) + go func() { // G2 + if rand.Intn(10) > 7 { + done <- false + return + } + done <- true + }() + select { + case <-bc.stop: + return + case <-done: + } + } +} + +func Grpc660() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { + bc := &benchmarkClient_grpc660{ + stop: make(chan bool), + } + go bc.doCloseLoopUnary() // G1 + go func() { // helper goroutine + bc.stop <- true + }() + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/grpc795.go b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc795.go new file mode 100644 index 00000000000000..72005cc844e225 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc795.go @@ -0,0 +1,74 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Grpc795", Grpc795) +} + +type Server_grpc795 struct { + mu sync.Mutex + drain bool +} + +func (s *Server_grpc795) GracefulStop() { + s.mu.Lock() + if s.drain { + s.mu.Lock() + return + } + s.drain = true + s.mu.Unlock() +} +func (s *Server_grpc795) Serve() { + s.mu.Lock() + s.mu.Unlock() +} + +func NewServer_grpc795() *Server_grpc795 { + return &Server_grpc795{} +} + +type test_grpc795 struct { + srv *Server_grpc795 +} + +func (te *test_grpc795) startServer() { + s := NewServer_grpc795() + te.srv = s + go s.Serve() +} + +func newTest_grpc795() *test_grpc795 { + return &test_grpc795{} +} + +func testServerGracefulStopIdempotent_grpc795() { + te := newTest_grpc795() + + te.startServer() + + for i := 0; i < 3; i++ { + te.srv.GracefulStop() + } +} + +func Grpc795() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 100; i++ { + go testServerGracefulStopIdempotent_grpc795() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/grpc862.go b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc862.go new file mode 100644 index 00000000000000..188b3b88ba5f8a --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/grpc862.go @@ -0,0 +1,105 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: grpc-go + * Issue or PR : https://github.com/grpc/grpc-go/pull/862 + * Buggy version: d8f4ebe77f6b7b6403d7f98626de8a534f9b93a7 + * fix commit-id: dd5645bebff44f6b88780bb949022a09eadd7dae + * Flaky: 100/100 + */ +package main + +import ( + "context" + "os" + "runtime" + "runtime/pprof" + "time" +) + +func init() { + register("Grpc862", Grpc862) +} + +type ClientConn_grpc862 struct { + ctx context.Context + cancel context.CancelFunc + conns []*addrConn_grpc862 +} + +func (cc *ClientConn_grpc862) Close() { + cc.cancel() + conns := cc.conns + cc.conns = nil + for _, ac := range conns { + ac.tearDown() + } +} + +func (cc *ClientConn_grpc862) resetAddrConn() { + ac := &addrConn_grpc862{ + cc: cc, + } + cc.conns = append(cc.conns, ac) + ac.ctx, ac.cancel = context.WithCancel(cc.ctx) + ac.resetTransport() +} + +type addrConn_grpc862 struct { + cc *ClientConn_grpc862 + ctx context.Context + cancel context.CancelFunc +} + +func (ac *addrConn_grpc862) resetTransport() { + for retries := 1; ; retries++ { + _ = 2 * time.Nanosecond * time.Duration(retries) + timeout := 10 * time.Nanosecond + _, cancel := context.WithTimeout(ac.ctx, timeout) + _ = time.Now() + cancel() + <-ac.ctx.Done() + return + } +} + +func (ac *addrConn_grpc862) tearDown() { + ac.cancel() +} + +func DialContext_grpc862(ctx context.Context) (conn *ClientConn_grpc862) { + cc := &ClientConn_grpc862{} + cc.ctx, cc.cancel = context.WithCancel(context.Background()) + defer func() { + select { + case <-ctx.Done(): + if conn != nil { + conn.Close() + } + conn = nil + default: + } + }() + go func() { // G2 + cc.resetAddrConn() + }() + return conn +} + +func Grpc862() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { + ctx, cancel := context.WithCancel(context.Background()) + go DialContext_grpc862(ctx) // G1 + go cancel() // helper goroutine + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/hugo3251.go b/src/runtime/testdata/testgoroutineleakprofile/goker/hugo3251.go new file mode 100644 index 00000000000000..3804692a8bf6bd --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/hugo3251.go @@ -0,0 +1,81 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "fmt" + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Hugo3251", Hugo3251) +} + +type remoteLock_hugo3251 struct { + sync.RWMutex // L1 + m map[string]*sync.Mutex // L2 +} + +func (l *remoteLock_hugo3251) URLLock(url string) { + l.Lock() // L1 + if _, ok := l.m[url]; !ok { + l.m[url] = &sync.Mutex{} + } + l.m[url].Lock() // L2 + runtime.Gosched() + l.Unlock() // L1 + // runtime.Gosched() +} + +func (l *remoteLock_hugo3251) URLUnlock(url string) { + l.RLock() // L1 + defer l.RUnlock() // L1 + if um, ok := l.m[url]; ok { + um.Unlock() // L2 + } +} + +func resGetRemote_hugo3251(remoteURLLock *remoteLock_hugo3251, url string) error { + remoteURLLock.URLLock(url) + defer func() { remoteURLLock.URLUnlock(url) }() + + return nil +} + +func Hugo3251() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(time.Second) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 11; i++ { + go func() { // G1 + url := "http://Foo.Bar/foo_Bar-Foo" + remoteURLLock := &remoteLock_hugo3251{m: make(map[string]*sync.Mutex)} + for range []bool{false, true} { + var wg sync.WaitGroup + for i := 0; i < 100; i++ { + wg.Add(1) + go func(gor int) { // G2 + defer wg.Done() + for j := 0; j < 200; j++ { + err := resGetRemote_hugo3251(remoteURLLock, url) + if err != nil { + fmt.Errorf("Error getting resource content: %s", err) + } + time.Sleep(300 * time.Nanosecond) + } + }(i) + } + wg.Wait() + } + }() + } +} \ No newline at end of file diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/hugo5379.go b/src/runtime/testdata/testgoroutineleakprofile/goker/hugo5379.go new file mode 100644 index 00000000000000..6a1bbe9a3f7767 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/hugo5379.go @@ -0,0 +1,317 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "context" + "log" + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Hugo5379", Hugo5379) +} + +type shortcodeHandler_hugo5379 struct { + p *PageWithoutContent_hugo5379 + contentShortcodes map[int]func() error + contentShortcodesDelta map[int]func() error + init sync.Once // O1 +} + +func (s *shortcodeHandler_hugo5379) executeShortcodesForDelta(p *PageWithoutContent_hugo5379) error { + for k, _ := range s.contentShortcodesDelta { + render := s.contentShortcodesDelta[k] + if err := render(); err != nil { + continue + } + } + return nil +} + +func (s *shortcodeHandler_hugo5379) updateDelta() { + s.init.Do(func() { + s.contentShortcodes = createShortcodeRenderers_hugo5379(s.p.withoutContent()) + }) + + delta := make(map[int]func() error) + + for k, v := range s.contentShortcodes { + if _, ok := delta[k]; !ok { + delta[k] = v + } + } + + s.contentShortcodesDelta = delta +} + +type Page_hugo5379 struct { + *pageInit_hugo5379 + *pageContentInit_hugo5379 + pageWithoutContent *PageWithoutContent_hugo5379 + contentInit sync.Once // O2 + contentInitMu sync.Mutex // L1 + shortcodeState *shortcodeHandler_hugo5379 +} + +func (p *Page_hugo5379) WordCount() { + p.initContentPlainAndMeta() +} + +func (p *Page_hugo5379) initContentPlainAndMeta() { + p.initContent() + p.initPlain(true) +} + +func (p *Page_hugo5379) initPlain(lock bool) { + p.plainInit.Do(func() { + if lock { + /// Double locking here. + p.contentInitMu.Lock() + defer p.contentInitMu.Unlock() + } + }) +} + +func (p *Page_hugo5379) withoutContent() *PageWithoutContent_hugo5379 { + p.pageInit_hugo5379.withoutContentInit.Do(func() { + p.pageWithoutContent = &PageWithoutContent_hugo5379{Page_hugo5379: p} + }) + return p.pageWithoutContent +} + +func (p *Page_hugo5379) prepareForRender() error { + var err error + if err = handleShortcodes_hugo5379(p.withoutContent()); err != nil { + return err + } + return nil +} + +func (p *Page_hugo5379) setContentInit() { + p.shortcodeState.updateDelta() +} + +func (p *Page_hugo5379) initContent() { + p.contentInit.Do(func() { + ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond) + defer cancel() + c := make(chan error, 1) + + go func() { // G2 + var err error + p.contentInitMu.Lock() // first lock here + defer p.contentInitMu.Unlock() + + err = p.prepareForRender() + if err != nil { + c <- err + return + } + c <- err + }() + + select { + case <-ctx.Done(): + case <-c: + } + }) +} + +type PageWithoutContent_hugo5379 struct { + *Page_hugo5379 +} + +type pageInit_hugo5379 struct { + withoutContentInit sync.Once +} + +type pageContentInit_hugo5379 struct { + contentInit sync.Once // O3 + plainInit sync.Once // O4 +} + +type HugoSites_hugo5379 struct { + Sites []*Site_hugo5379 +} + +func (h *HugoSites_hugo5379) render() { + for _, s := range h.Sites { + for _, s2 := range h.Sites { + s2.preparePagesForRender() + } + s.renderPages() + } +} + +func (h *HugoSites_hugo5379) Build() { + h.render() +} + +type Pages_hugo5379 []*Page_hugo5379 + +type PageCollections_hugo5379 struct { + Pages Pages_hugo5379 +} + +type Site_hugo5379 struct { + *PageCollections_hugo5379 +} + +func (s *Site_hugo5379) preparePagesForRender() { + for _, p := range s.Pages { + p.setContentInit() + } +} + +func (s *Site_hugo5379) renderForLayouts() { + /// Omit reflections + for _, p := range s.Pages { + p.WordCount() + } +} + +func (s *Site_hugo5379) renderAndWritePage() { + s.renderForLayouts() +} + +func (s *Site_hugo5379) renderPages() { + numWorkers := 2 + wg := &sync.WaitGroup{} + + for i := 0; i < numWorkers; i++ { + wg.Add(1) + go pageRenderer_hugo5379(s, wg) // G3 + } + + wg.Wait() +} + +type sitesBuilder_hugo5379 struct { + H *HugoSites_hugo5379 +} + +func (s *sitesBuilder_hugo5379) Build() *sitesBuilder_hugo5379 { + return s.build() +} + +func (s *sitesBuilder_hugo5379) build() *sitesBuilder_hugo5379 { + s.H.Build() + return s +} + +func (s *sitesBuilder_hugo5379) CreateSitesE() error { + sites, err := NewHugoSites_hugo5379() + if err != nil { + return err + } + s.H = sites + return nil +} + +func (s *sitesBuilder_hugo5379) CreateSites() *sitesBuilder_hugo5379 { + if err := s.CreateSitesE(); err != nil { + log.Fatalf("Failed to create sites: %s", err) + } + return s +} + +func newHugoSites_hugo5379(sites ...*Site_hugo5379) (*HugoSites_hugo5379, error) { + h := &HugoSites_hugo5379{Sites: sites} + return h, nil +} + +func newSite_hugo5379() *Site_hugo5379 { + c := &PageCollections_hugo5379{} + s := &Site_hugo5379{ + PageCollections_hugo5379: c, + } + return s +} + +func createSitesFromConfig_hugo5379() []*Site_hugo5379 { + var ( + sites []*Site_hugo5379 + ) + + var s *Site_hugo5379 = newSite_hugo5379() + sites = append(sites, s) + return sites +} + +func NewHugoSites_hugo5379() (*HugoSites_hugo5379, error) { + sites := createSitesFromConfig_hugo5379() + return newHugoSites_hugo5379(sites...) +} + +func prepareShortcodeForPage_hugo5379(p *PageWithoutContent_hugo5379) map[int]func() error { + m := make(map[int]func() error) + m[0] = func() error { + return renderShortcode_hugo5379(p) + } + return m +} + +func renderShortcode_hugo5379(p *PageWithoutContent_hugo5379) error { + return renderShortcodeWithPage_hugo5379(p) +} + +func renderShortcodeWithPage_hugo5379(p *PageWithoutContent_hugo5379) error { + /// Omit reflections + p.WordCount() + return nil +} + +func createShortcodeRenderers_hugo5379(p *PageWithoutContent_hugo5379) map[int]func() error { + return prepareShortcodeForPage_hugo5379(p) +} + +func newShortcodeHandler_hugo5379(p *Page_hugo5379) *shortcodeHandler_hugo5379 { + return &shortcodeHandler_hugo5379{ + p: p.withoutContent(), + contentShortcodes: make(map[int]func() error), + contentShortcodesDelta: make(map[int]func() error), + } +} + +func handleShortcodes_hugo5379(p *PageWithoutContent_hugo5379) error { + return p.shortcodeState.executeShortcodesForDelta(p) +} + +func pageRenderer_hugo5379(s *Site_hugo5379, wg *sync.WaitGroup) { + defer wg.Done() + s.renderAndWritePage() +} + +func Hugo5379() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { // G1 + b := &sitesBuilder_hugo5379{} + s := b.CreateSites() + for _, site := range s.H.Sites { + p := &Page_hugo5379{ + pageInit_hugo5379: &pageInit_hugo5379{}, + pageContentInit_hugo5379: &pageContentInit_hugo5379{}, + pageWithoutContent: &PageWithoutContent_hugo5379{}, + contentInit: sync.Once{}, + contentInitMu: sync.Mutex{}, + shortcodeState: nil, + } + p.shortcodeState = newShortcodeHandler_hugo5379(p) + site.Pages = append(site.Pages, p) + } + s.Build() + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/istio16224.go b/src/runtime/testdata/testgoroutineleakprofile/goker/istio16224.go new file mode 100644 index 00000000000000..839051cc64a18d --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/istio16224.go @@ -0,0 +1,129 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Istio16224", Istio16224) +} + +type ConfigStoreCache_istio16224 interface { + RegisterEventHandler(handler func()) + Run() +} + +type Event_istio16224 int + +type Handler_istio16224 func(Event_istio16224) + +type configstoreMonitor_istio16224 struct { + handlers []Handler_istio16224 + eventCh chan Event_istio16224 +} + +func (m *configstoreMonitor_istio16224) Run(stop <-chan struct{}) { + for { + select { + case <-stop: + // This bug is not descibed, but is a true positive (in our eyes) + // In a real run main exits when the goro is blocked here. + if _, ok := <-m.eventCh; ok { + close(m.eventCh) + } + return + case ce, ok := <-m.eventCh: + if ok { + m.processConfigEvent(ce) + } + } + } +} + +func (m *configstoreMonitor_istio16224) processConfigEvent(ce Event_istio16224) { + m.applyHandlers(ce) +} + +func (m *configstoreMonitor_istio16224) AppendEventHandler(h Handler_istio16224) { + m.handlers = append(m.handlers, h) +} + +func (m *configstoreMonitor_istio16224) applyHandlers(e Event_istio16224) { + for _, f := range m.handlers { + f(e) + } +} +func (m *configstoreMonitor_istio16224) ScheduleProcessEvent(configEvent Event_istio16224) { + m.eventCh <- configEvent +} + +type Monitor_istio16224 interface { + Run(<-chan struct{}) + AppendEventHandler(Handler_istio16224) + ScheduleProcessEvent(Event_istio16224) +} + +type controller_istio16224 struct { + monitor Monitor_istio16224 +} + +func (c *controller_istio16224) RegisterEventHandler(f func(Event_istio16224)) { + c.monitor.AppendEventHandler(f) +} + +func (c *controller_istio16224) Run(stop <-chan struct{}) { + c.monitor.Run(stop) +} + +func (c *controller_istio16224) Create() { + c.monitor.ScheduleProcessEvent(Event_istio16224(0)) +} + +func NewMonitor_istio16224() Monitor_istio16224 { + return NewBufferedMonitor_istio16224() +} + +func NewBufferedMonitor_istio16224() Monitor_istio16224 { + return &configstoreMonitor_istio16224{ + eventCh: make(chan Event_istio16224), + } +} + +func Istio16224() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + controller := &controller_istio16224{monitor: NewMonitor_istio16224()} + done := make(chan bool) + lock := sync.Mutex{} + controller.RegisterEventHandler(func(event Event_istio16224) { + lock.Lock() + defer lock.Unlock() + done <- true + }) + + stop := make(chan struct{}) + go controller.Run(stop) + + controller.Create() + + lock.Lock() // blocks + lock.Unlock() + <-done + + close(stop) + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/istio17860.go b/src/runtime/testdata/testgoroutineleakprofile/goker/istio17860.go new file mode 100644 index 00000000000000..aa8317c6d5f41b --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/istio17860.go @@ -0,0 +1,144 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "context" + "os" + "runtime/pprof" + + "sync" + "time" +) + +func init() { + register("Istio17860", Istio17860) +} + +type Proxy_istio17860 interface { + IsLive() bool +} + +type TestProxy_istio17860 struct { + live func() bool +} + +func (tp TestProxy_istio17860) IsLive() bool { + if tp.live == nil { + return true + } + return tp.live() +} + +type Agent_istio17860 interface { + Run(ctx context.Context) + Restart() +} + +type exitStatus_istio17860 int + +type agent_istio17860 struct { + proxy Proxy_istio17860 + mu *sync.Mutex + statusCh chan exitStatus_istio17860 + currentEpoch int + activeEpochs map[int]struct{} +} + +func (a *agent_istio17860) Run(ctx context.Context) { + for { + select { + case status := <-a.statusCh: + a.mu.Lock() + delete(a.activeEpochs, int(status)) + active := len(a.activeEpochs) + a.mu.Unlock() + if active == 0 { + return + } + case <-ctx.Done(): + return + } + } +} + +func (a *agent_istio17860) Restart() { + a.mu.Lock() + defer a.mu.Unlock() + + a.waitUntilLive() + a.currentEpoch++ + a.activeEpochs[a.currentEpoch] = struct{}{} + + go a.runWait(a.currentEpoch) +} + +func (a *agent_istio17860) runWait(epoch int) { + a.statusCh <- exitStatus_istio17860(epoch) +} + +func (a *agent_istio17860) waitUntilLive() { + if len(a.activeEpochs) == 0 { + return + } + + interval := time.NewTicker(30 * time.Nanosecond) + timer := time.NewTimer(100 * time.Nanosecond) + defer func() { + interval.Stop() + timer.Stop() + }() + + if a.proxy.IsLive() { + return + } + + for { + select { + case <-timer.C: + return + case <-interval.C: + if a.proxy.IsLive() { + return + } + } + } +} + +func NewAgent_istio17860(proxy Proxy_istio17860) Agent_istio17860 { + return &agent_istio17860{ + proxy: proxy, + mu: &sync.Mutex{}, + statusCh: make(chan exitStatus_istio17860), + activeEpochs: make(map[int]struct{}), + } +} + +func Istio17860() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + ctx, cancel := context.WithCancel(context.Background()) + defer cancel() + + neverLive := func() bool { + return false + } + + a := NewAgent_istio17860(TestProxy_istio17860{live: neverLive}) + go func() { a.Run(ctx) }() + + a.Restart() + go a.Restart() + + time.Sleep(200 * time.Nanosecond) + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/istio18454.go b/src/runtime/testdata/testgoroutineleakprofile/goker/istio18454.go new file mode 100644 index 00000000000000..b410c490322440 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/istio18454.go @@ -0,0 +1,154 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "context" + "os" + "runtime/pprof" + + "sync" + "time" +) + +func init() { + register("Istio18454", Istio18454) +} + +const eventChCap_istio18454 = 1024 + +type Worker_istio18454 struct { + ctx context.Context + ctxCancel context.CancelFunc +} + +func (w *Worker_istio18454) Start(setupFn func(), runFn func(c context.Context)) { + if setupFn != nil { + setupFn() + } + go func() { + runFn(w.ctx) + }() +} + +func (w *Worker_istio18454) Stop() { + w.ctxCancel() +} + +type Strategy_istio18454 struct { + timer *time.Timer + timerFrequency time.Duration + stateLock sync.Mutex + resetChan chan struct{} + worker *Worker_istio18454 + startTimerFn func() +} + +func (s *Strategy_istio18454) OnChange() { + s.stateLock.Lock() + if s.timer != nil { + s.stateLock.Unlock() + s.resetChan <- struct{}{} + return + } + s.startTimerFn() + s.stateLock.Unlock() +} + +func (s *Strategy_istio18454) startTimer() { + s.timer = time.NewTimer(s.timerFrequency) + eventLoop := func(ctx context.Context) { + for { + select { + case <-s.timer.C: + case <-s.resetChan: + if !s.timer.Stop() { + <-s.timer.C + } + s.timer.Reset(s.timerFrequency) + case <-ctx.Done(): + s.timer.Stop() + return + } + } + } + s.worker.Start(nil, eventLoop) +} + +func (s *Strategy_istio18454) Close() { + s.worker.Stop() +} + +type Event_istio18454 int + +type Processor_istio18454 struct { + stateStrategy *Strategy_istio18454 + worker *Worker_istio18454 + eventCh chan Event_istio18454 +} + +func (p *Processor_istio18454) processEvent() { + p.stateStrategy.OnChange() +} + +func (p *Processor_istio18454) Start() { + setupFn := func() { + for i := 0; i < eventChCap_istio18454; i++ { + p.eventCh <- Event_istio18454(0) + } + } + runFn := func(ctx context.Context) { + defer func() { + p.stateStrategy.Close() + }() + for { + select { + case <-ctx.Done(): + return + case <-p.eventCh: + p.processEvent() + } + } + } + p.worker.Start(setupFn, runFn) +} + +func (p *Processor_istio18454) Stop() { + p.worker.Stop() +} + +func NewWorker_istio18454() *Worker_istio18454 { + worker := &Worker_istio18454{} + worker.ctx, worker.ctxCancel = context.WithCancel(context.Background()) + return worker +} + +func Istio18454() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + stateStrategy := &Strategy_istio18454{ + timerFrequency: time.Nanosecond, + resetChan: make(chan struct{}, 1), + worker: NewWorker_istio18454(), + } + stateStrategy.startTimerFn = stateStrategy.startTimer + + p := &Processor_istio18454{ + stateStrategy: stateStrategy, + worker: NewWorker_istio18454(), + eventCh: make(chan Event_istio18454, eventChCap_istio18454), + } + + p.Start() + defer p.Stop() + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes10182.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes10182.go new file mode 100644 index 00000000000000..0eca5f41fbfab4 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes10182.go @@ -0,0 +1,95 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: kubernetes + * Issue or PR : https://github.com/kubernetes/kubernetes/pull/10182 + * Buggy version: 4b990d128a17eea9058d28a3b3688ab8abafbd94 + * fix commit-id: 64ad3e17ad15cd0f9a4fd86706eec1c572033254 + * Flaky: 15/100 + */ +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes10182", Kubernetes10182) +} + +type statusManager_kubernetes10182 struct { + podStatusesLock sync.RWMutex + podStatusChannel chan bool +} + +func (s *statusManager_kubernetes10182) Start() { + go func() { + for i := 0; i < 2; i++ { + s.syncBatch() + } + }() +} + +func (s *statusManager_kubernetes10182) syncBatch() { + runtime.Gosched() + <-s.podStatusChannel + s.DeletePodStatus() +} + +func (s *statusManager_kubernetes10182) DeletePodStatus() { + s.podStatusesLock.Lock() + defer s.podStatusesLock.Unlock() +} + +func (s *statusManager_kubernetes10182) SetPodStatus() { + s.podStatusesLock.Lock() + defer s.podStatusesLock.Unlock() + s.podStatusChannel <- true +} + +func NewStatusManager_kubernetes10182() *statusManager_kubernetes10182 { + return &statusManager_kubernetes10182{ + podStatusChannel: make(chan bool), + } +} + +// Example of deadlock trace: +// +// G1 G2 G3 +// -------------------------------------------------------------------------------- +// s.Start() +// s.syncBatch() +// s.SetPodStatus() +// <-s.podStatusChannel +// s.podStatusesLock.Lock() +// s.podStatusChannel <- true +// s.podStatusesLock.Unlock() +// return +// s.DeletePodStatus() +// s.podStatusesLock.Lock() +// s.podStatusChannel <- true +// s.podStatusesLock.Lock() +// -----------------------------------G1,G3 leak------------------------------------- + +func Kubernetes10182() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 1000; i++ { + go func() { + s := NewStatusManager_kubernetes10182() + go s.Start() + go s.SetPodStatus() + go s.SetPodStatus() + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes11298.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes11298.go new file mode 100644 index 00000000000000..36405f240a6612 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes11298.go @@ -0,0 +1,118 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes11298", Kubernetes11298) +} + +type Signal_kubernetes11298 <-chan struct{} + +func After_kubernetes11298(f func()) Signal_kubernetes11298 { + ch := make(chan struct{}) + go func() { + defer close(ch) + if f != nil { + f() + } + }() + return Signal_kubernetes11298(ch) +} + +func Until_kubernetes11298(f func(), period time.Duration, stopCh <-chan struct{}) { + if f == nil { + return + } + for { + select { + case <-stopCh: + return + default: + } + f() + select { + case <-stopCh: + case <-time.After(period): + } + } + +} + +type notifier_kubernetes11298 struct { + lock sync.Mutex + cond *sync.Cond +} + +// abort will be closed no matter what +func (n *notifier_kubernetes11298) serviceLoop(abort <-chan struct{}) { + n.lock.Lock() + defer n.lock.Unlock() + for { + select { + case <-abort: + return + default: + ch := After_kubernetes11298(func() { + n.cond.Wait() + }) + select { + case <-abort: + n.cond.Signal() + <-ch + return + case <-ch: + } + } + } +} + +// abort will be closed no matter what +func Notify_kubernetes11298(abort <-chan struct{}) { + n := ¬ifier_kubernetes11298{} + n.cond = sync.NewCond(&n.lock) + finished := After_kubernetes11298(func() { + Until_kubernetes11298(func() { + for { + select { + case <-abort: + return + default: + func() { + n.lock.Lock() + defer n.lock.Unlock() + n.cond.Signal() + }() + } + } + }, 0, abort) + }) + Until_kubernetes11298(func() { n.serviceLoop(finished) }, 0, abort) +} +func Kubernetes11298() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 1000; i++ { + go func() { + done := make(chan struct{}) + notifyDone := After_kubernetes11298(func() { Notify_kubernetes11298(done) }) + go func() { + defer close(done) + time.Sleep(300 * time.Nanosecond) + }() + <-notifyDone + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes13135.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes13135.go new file mode 100644 index 00000000000000..f6aa8b9ddfe178 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes13135.go @@ -0,0 +1,166 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: kubernetes + * Issue or PR : https://github.com/kubernetes/kubernetes/pull/13135 + * Buggy version: 6ced66249d4fd2a81e86b4a71d8df0139fe5ceae + * fix commit-id: a12b7edc42c5c06a2e7d9f381975658692951d5a + * Flaky: 93/100 + */ +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes13135", Kubernetes13135) +} + +var ( + StopChannel_kubernetes13135 chan struct{} +) + +func Util_kubernetes13135(f func(), period time.Duration, stopCh <-chan struct{}) { + for { + select { + case <-stopCh: + return + default: + } + func() { + f() + }() + time.Sleep(period) + } +} + +type Store_kubernetes13135 interface { + Add(obj interface{}) + Replace(obj interface{}) +} + +type Reflector_kubernetes13135 struct { + store Store_kubernetes13135 +} + +func (r *Reflector_kubernetes13135) ListAndWatch(stopCh <-chan struct{}) error { + r.syncWith() + return nil +} + +func NewReflector_kubernetes13135(store Store_kubernetes13135) *Reflector_kubernetes13135 { + return &Reflector_kubernetes13135{ + store: store, + } +} + +func (r *Reflector_kubernetes13135) syncWith() { + r.store.Replace(nil) +} + +type Cacher_kubernetes13135 struct { + sync.Mutex + initialized sync.WaitGroup + initOnce sync.Once + watchCache *WatchCache_kubernetes13135 + reflector *Reflector_kubernetes13135 +} + +func (c *Cacher_kubernetes13135) processEvent() { + c.Lock() + defer c.Unlock() +} + +func (c *Cacher_kubernetes13135) startCaching(stopChannel <-chan struct{}) { + c.Lock() + for { + err := c.reflector.ListAndWatch(stopChannel) + if err == nil { + break + } + } +} + +type WatchCache_kubernetes13135 struct { + sync.RWMutex + onReplace func() + onEvent func() +} + +func (w *WatchCache_kubernetes13135) SetOnEvent(onEvent func()) { + w.Lock() + defer w.Unlock() + w.onEvent = onEvent +} + +func (w *WatchCache_kubernetes13135) SetOnReplace(onReplace func()) { + w.Lock() + defer w.Unlock() + w.onReplace = onReplace +} + +func (w *WatchCache_kubernetes13135) processEvent() { + w.Lock() + defer w.Unlock() + if w.onEvent != nil { + w.onEvent() + } +} + +func (w *WatchCache_kubernetes13135) Add(obj interface{}) { + w.processEvent() +} + +func (w *WatchCache_kubernetes13135) Replace(obj interface{}) { + w.Lock() + defer w.Unlock() + if w.onReplace != nil { + w.onReplace() + } +} + +func NewCacher_kubernetes13135(stopCh <-chan struct{}) *Cacher_kubernetes13135 { + watchCache := &WatchCache_kubernetes13135{} + cacher := &Cacher_kubernetes13135{ + initialized: sync.WaitGroup{}, + watchCache: watchCache, + reflector: NewReflector_kubernetes13135(watchCache), + } + cacher.initialized.Add(1) + watchCache.SetOnReplace(func() { + cacher.initOnce.Do(func() { cacher.initialized.Done() }) + cacher.Unlock() + }) + watchCache.SetOnEvent(cacher.processEvent) + go Util_kubernetes13135(func() { cacher.startCaching(stopCh) }, 0, stopCh) // G2 + cacher.initialized.Wait() + return cacher +} + +func Kubernetes13135() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + StopChannel_kubernetes13135 = make(chan struct{}) + for i := 0; i < 50; i++ { + go func() { + // Should create a local channel. Using a single global channel + // concurrently will cause a deadlock which does not actually exist + // in the original microbenchmark. + StopChannel_kubernetes13135 := make(chan struct{}) + + c := NewCacher_kubernetes13135(StopChannel_kubernetes13135) // G1 + go c.watchCache.Add(nil) // G3 + go close(StopChannel_kubernetes13135) + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes1321.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes1321.go new file mode 100644 index 00000000000000..6c0139a9d24fcb --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes1321.go @@ -0,0 +1,100 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: kubernetes + * Issue or PR : https://github.com/kubernetes/kubernetes/pull/1321 + * Buggy version: 9cd0fc70f1ca852c903b18b0933991036b3b2fa1 + * fix commit-id: 435e0b73bb99862f9dedf56a50260ff3dfef14ff + * Flaky: 1/100 + */ +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes1321", Kubernetes1321) +} + +type muxWatcher_kubernetes1321 struct { + result chan struct{} + m *Mux_kubernetes1321 + id int64 +} + +func (mw *muxWatcher_kubernetes1321) Stop() { + mw.m.stopWatching(mw.id) +} + +type Mux_kubernetes1321 struct { + lock sync.Mutex + watchers map[int64]*muxWatcher_kubernetes1321 +} + +func NewMux_kubernetes1321() *Mux_kubernetes1321 { + m := &Mux_kubernetes1321{ + watchers: map[int64]*muxWatcher_kubernetes1321{}, + } + go m.loop() // G2 + return m +} + +func (m *Mux_kubernetes1321) Watch() *muxWatcher_kubernetes1321 { + mw := &muxWatcher_kubernetes1321{ + result: make(chan struct{}), + m: m, + id: int64(len(m.watchers)), + } + m.watchers[mw.id] = mw + runtime.Gosched() + return mw +} + +func (m *Mux_kubernetes1321) loop() { + for i := 0; i < 100; i++ { + m.distribute() + } +} + +func (m *Mux_kubernetes1321) distribute() { + m.lock.Lock() + defer m.lock.Unlock() + for _, w := range m.watchers { + w.result <- struct{}{} + runtime.Gosched() + } +} + +func (m *Mux_kubernetes1321) stopWatching(id int64) { + m.lock.Lock() + defer m.lock.Unlock() + w, ok := m.watchers[id] + if !ok { + return + } + delete(m.watchers, id) + close(w.result) +} + +func testMuxWatcherClose_kubernetes1321() { + m := NewMux_kubernetes1321() + m.watchers[m.Watch().id].Stop() +} + +func Kubernetes1321() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 1000; i++ { + go testMuxWatcherClose_kubernetes1321() // G1 + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes25331.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes25331.go new file mode 100644 index 00000000000000..323cb236c0687a --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes25331.go @@ -0,0 +1,72 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: kubernetes + * Issue or PR : https://github.com/kubernetes/kubernetes/pull/25331 + * Buggy version: 5dd087040bb13434f1ddf2f0693d0203c30f28cb + * fix commit-id: 97f4647dc3d8cf46c2b66b89a31c758a6edfb57c + * Flaky: 100/100 + */ +package main + +import ( + "context" + "errors" + "os" + "runtime" + "runtime/pprof" +) + +func init() { + register("Kubernetes25331", Kubernetes25331) +} + +type watchChan_kubernetes25331 struct { + ctx context.Context + cancel context.CancelFunc + resultChan chan bool + errChan chan error +} + +func (wc *watchChan_kubernetes25331) Stop() { + wc.errChan <- errors.New("Error") + wc.cancel() +} + +func (wc *watchChan_kubernetes25331) run() { + select { + case err := <-wc.errChan: + errResult := len(err.Error()) != 0 + wc.cancel() // Removed in fix + wc.resultChan <- errResult + case <-wc.ctx.Done(): + } +} + +func NewWatchChan_kubernetes25331() *watchChan_kubernetes25331 { + ctx, cancel := context.WithCancel(context.Background()) + return &watchChan_kubernetes25331{ + ctx: ctx, + cancel: cancel, + resultChan: make(chan bool), + errChan: make(chan error), + } +} + +func Kubernetes25331() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { + wc := NewWatchChan_kubernetes25331() + go wc.run() // G1 + go wc.Stop() // G2 + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes26980.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes26980.go new file mode 100644 index 00000000000000..38e53cf4ad7218 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes26980.go @@ -0,0 +1,87 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes26980", Kubernetes26980) +} + +type processorListener_kubernetes26980 struct { + lock sync.RWMutex + cond sync.Cond + + pendingNotifications []interface{} +} + +func (p *processorListener_kubernetes26980) add(notification interface{}) { + p.lock.Lock() + defer p.lock.Unlock() + + p.pendingNotifications = append(p.pendingNotifications, notification) + p.cond.Broadcast() +} + +func (p *processorListener_kubernetes26980) pop(stopCh <-chan struct{}) { + p.lock.Lock() + runtime.Gosched() + defer p.lock.Unlock() + for { + for len(p.pendingNotifications) == 0 { + select { + case <-stopCh: + return + default: + } + p.cond.Wait() + } + select { + case <-stopCh: + return + } + } +} + +func newProcessListener_kubernetes26980() *processorListener_kubernetes26980 { + ret := &processorListener_kubernetes26980{ + pendingNotifications: []interface{}{}, + } + ret.cond.L = &ret.lock + return ret +} +func Kubernetes26980() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 3000; i++ { + go func() { + pl := newProcessListener_kubernetes26980() + stopCh := make(chan struct{}) + defer close(stopCh) + pl.add(1) + runtime.Gosched() + go pl.pop(stopCh) + + resultCh := make(chan struct{}) + go func() { + pl.lock.Lock() + close(resultCh) + }() + runtime.Gosched() + <-resultCh + pl.lock.Unlock() + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes30872.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes30872.go new file mode 100644 index 00000000000000..00cdcf2b678692 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes30872.go @@ -0,0 +1,223 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes30872", Kubernetes30872) +} + +type PopProcessFunc_kubernetes30872 func() + +type ProcessFunc_kubernetes30872 func() + +func Util_kubernetes30872(f func(), stopCh <-chan struct{}) { + JitterUntil_kubernetes30872(f, stopCh) +} + +func JitterUntil_kubernetes30872(f func(), stopCh <-chan struct{}) { + for { + select { + case <-stopCh: + return + default: + } + func() { + f() + }() + } +} + +type Queue_kubernetes30872 interface { + HasSynced() + Pop(PopProcessFunc_kubernetes30872) +} + +type Config_kubernetes30872 struct { + Queue Queue_kubernetes30872 + Process ProcessFunc_kubernetes30872 +} + +type Controller_kubernetes30872 struct { + config Config_kubernetes30872 +} + +func (c *Controller_kubernetes30872) Run(stopCh <-chan struct{}) { + Util_kubernetes30872(c.processLoop, stopCh) +} + +func (c *Controller_kubernetes30872) HasSynced() { + c.config.Queue.HasSynced() +} + +func (c *Controller_kubernetes30872) processLoop() { + c.config.Queue.Pop(PopProcessFunc_kubernetes30872(c.config.Process)) +} + +type ControllerInterface_kubernetes30872 interface { + Run(<-chan struct{}) + HasSynced() +} + +type ResourceEventHandler_kubernetes30872 interface { + OnAdd() +} + +type ResourceEventHandlerFuncs_kubernetes30872 struct { + AddFunc func() +} + +func (r ResourceEventHandlerFuncs_kubernetes30872) OnAdd() { + if r.AddFunc != nil { + r.AddFunc() + } +} + +type informer_kubernetes30872 struct { + controller ControllerInterface_kubernetes30872 + + stopChan chan struct{} +} + +type federatedInformerImpl_kubernetes30872 struct { + sync.Mutex + clusterInformer informer_kubernetes30872 +} + +func (f *federatedInformerImpl_kubernetes30872) ClustersSynced() { + f.Lock() // L1 + defer f.Unlock() + f.clusterInformer.controller.HasSynced() +} + +func (f *federatedInformerImpl_kubernetes30872) addCluster() { + f.Lock() // L1 + defer f.Unlock() +} + +func (f *federatedInformerImpl_kubernetes30872) Start() { + f.Lock() // L1 + defer f.Unlock() + + f.clusterInformer.stopChan = make(chan struct{}) + go f.clusterInformer.controller.Run(f.clusterInformer.stopChan) // G2 + runtime.Gosched() +} + +func (f *federatedInformerImpl_kubernetes30872) Stop() { + f.Lock() // L1 + defer f.Unlock() + close(f.clusterInformer.stopChan) +} + +type DelayingDeliverer_kubernetes30872 struct{} + +func (d *DelayingDeliverer_kubernetes30872) StartWithHandler(handler func()) { + go func() { // G4 + handler() + }() +} + +type FederationView_kubernetes30872 interface { + ClustersSynced() +} + +type FederatedInformer_kubernetes30872 interface { + FederationView_kubernetes30872 + Start() + Stop() +} + +type NamespaceController_kubernetes30872 struct { + namespaceDeliverer *DelayingDeliverer_kubernetes30872 + namespaceFederatedInformer FederatedInformer_kubernetes30872 +} + +func (nc *NamespaceController_kubernetes30872) isSynced() { + nc.namespaceFederatedInformer.ClustersSynced() +} + +func (nc *NamespaceController_kubernetes30872) reconcileNamespace() { + nc.isSynced() +} + +func (nc *NamespaceController_kubernetes30872) Run(stopChan <-chan struct{}) { + nc.namespaceFederatedInformer.Start() + go func() { // G3 + <-stopChan + nc.namespaceFederatedInformer.Stop() + }() + nc.namespaceDeliverer.StartWithHandler(func() { + nc.reconcileNamespace() + }) +} + +type DeltaFIFO_kubernetes30872 struct { + lock sync.RWMutex +} + +func (f *DeltaFIFO_kubernetes30872) HasSynced() { + f.lock.Lock() // L2 + defer f.lock.Unlock() +} + +func (f *DeltaFIFO_kubernetes30872) Pop(process PopProcessFunc_kubernetes30872) { + f.lock.Lock() // L2 + defer f.lock.Unlock() + process() +} + +func NewFederatedInformer_kubernetes30872() FederatedInformer_kubernetes30872 { + federatedInformer := &federatedInformerImpl_kubernetes30872{} + federatedInformer.clusterInformer.controller = NewInformer_kubernetes30872( + ResourceEventHandlerFuncs_kubernetes30872{ + AddFunc: func() { + federatedInformer.addCluster() + }, + }) + return federatedInformer +} + +func NewInformer_kubernetes30872(h ResourceEventHandler_kubernetes30872) *Controller_kubernetes30872 { + fifo := &DeltaFIFO_kubernetes30872{} + cfg := &Config_kubernetes30872{ + Queue: fifo, + Process: func() { + h.OnAdd() + }, + } + return &Controller_kubernetes30872{config: *cfg} +} + +func NewNamespaceController_kubernetes30872() *NamespaceController_kubernetes30872 { + nc := &NamespaceController_kubernetes30872{} + nc.namespaceDeliverer = &DelayingDeliverer_kubernetes30872{} + nc.namespaceFederatedInformer = NewFederatedInformer_kubernetes30872() + return nc +} + +func Kubernetes30872() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { // G1 + namespaceController := NewNamespaceController_kubernetes30872() + stop := make(chan struct{}) + namespaceController.Run(stop) + close(stop) + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes38669.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes38669.go new file mode 100644 index 00000000000000..27020d580493bf --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes38669.go @@ -0,0 +1,83 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Kubernetes38669", Kubernetes38669) +} + +type Event_kubernetes38669 int +type watchCacheEvent_kubernetes38669 int + +type cacheWatcher_kubernetes38669 struct { + sync.Mutex + input chan watchCacheEvent_kubernetes38669 + result chan Event_kubernetes38669 + stopped bool +} + +func (c *cacheWatcher_kubernetes38669) process(initEvents []watchCacheEvent_kubernetes38669) { + for _, event := range initEvents { + c.sendWatchCacheEvent(&event) + } + defer close(c.result) + defer c.Stop() + for { + _, ok := <-c.input + if !ok { + return + } + } +} + +func (c *cacheWatcher_kubernetes38669) sendWatchCacheEvent(event *watchCacheEvent_kubernetes38669) { + c.result <- Event_kubernetes38669(*event) +} + +func (c *cacheWatcher_kubernetes38669) Stop() { + c.stop() +} + +func (c *cacheWatcher_kubernetes38669) stop() { + c.Lock() + defer c.Unlock() + if !c.stopped { + c.stopped = true + close(c.input) + } +} + +func newCacheWatcher_kubernetes38669(chanSize int, initEvents []watchCacheEvent_kubernetes38669) *cacheWatcher_kubernetes38669 { + watcher := &cacheWatcher_kubernetes38669{ + input: make(chan watchCacheEvent_kubernetes38669, chanSize), + result: make(chan Event_kubernetes38669, chanSize), + stopped: false, + } + go watcher.process(initEvents) + return watcher +} + +func Kubernetes38669() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { + initEvents := []watchCacheEvent_kubernetes38669{1, 2} + w := newCacheWatcher_kubernetes38669(0, initEvents) + w.Stop() + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes5316.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes5316.go new file mode 100644 index 00000000000000..fd51484a0f773b --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes5316.go @@ -0,0 +1,68 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: kubernetes + * Issue or PR : https://github.com/kubernetes/kubernetes/pull/5316 + * Buggy version: c868b0bbf09128960bc7c4ada1a77347a464d876 + * fix commit-id: cc3a433a7abc89d2f766d4c87eaae9448e3dc091 + * Flaky: 100/100 + */ + +package main + +import ( + "errors" + "math/rand" + "os" + "runtime" + "runtime/pprof" + "time" +) + +func init() { + register("Kubernetes5316", Kubernetes5316) +} + +func finishRequest_kubernetes5316(timeout time.Duration, fn func() error) { + ch := make(chan bool) + errCh := make(chan error) + go func() { // G2 + if err := fn(); err != nil { + errCh <- err + } else { + ch <- true + } + }() + + select { + case <-ch: + case <-errCh: + case <-time.After(timeout): + } +} + +func Kubernetes5316() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Wait a bit because the child goroutine relies on timed operations. + time.Sleep(100 * time.Millisecond) + + // Yield several times to allow the child goroutine to run + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { + fn := func() error { + time.Sleep(2 * time.Millisecond) + if rand.Intn(10) > 5 { + return errors.New("Error") + } + return nil + } + go finishRequest_kubernetes5316(time.Microsecond, fn) // G1 + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes58107.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes58107.go new file mode 100644 index 00000000000000..0ca707e981693a --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes58107.go @@ -0,0 +1,108 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: kubernetes + * Tag: Reproduce misbehavior + * Issue or PR : https://github.com/kubernetes/kubernetes/pull/58107 + * Buggy version: 2f17d782eb2772d6401da7ddced9ac90656a7a79 + * fix commit-id: 010a127314a935d8d038f8dd4559fc5b249813e4 + * Flaky: 53/100 + */ + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes58107", Kubernetes58107) +} + +type RateLimitingInterface_kubernetes58107 interface { + Get() + Put() +} + +type Type_kubernetes58107 struct { + cond *sync.Cond +} + +func (q *Type_kubernetes58107) Get() { + q.cond.L.Lock() + defer q.cond.L.Unlock() + q.cond.Wait() +} + +func (q *Type_kubernetes58107) Put() { + q.cond.Signal() +} + +type ResourceQuotaController_kubernetes58107 struct { + workerLock sync.RWMutex + queue RateLimitingInterface_kubernetes58107 + missingUsageQueue RateLimitingInterface_kubernetes58107 +} + +func (rq *ResourceQuotaController_kubernetes58107) worker(queue RateLimitingInterface_kubernetes58107, _ string) { + workFunc := func() bool { + rq.workerLock.RLock() + defer rq.workerLock.RUnlock() + queue.Get() + return true + } + for { + if quit := workFunc(); quit { + return + } + } +} + +func (rq *ResourceQuotaController_kubernetes58107) Run() { + go rq.worker(rq.queue, "G1") // G3 + go rq.worker(rq.missingUsageQueue, "G2") // G4 +} + +func (rq *ResourceQuotaController_kubernetes58107) Sync() { + for i := 0; i < 100000; i++ { + rq.workerLock.Lock() + runtime.Gosched() + rq.workerLock.Unlock() + } +} + +func (rq *ResourceQuotaController_kubernetes58107) HelperSignals() { + for i := 0; i < 100000; i++ { + rq.queue.Put() + rq.missingUsageQueue.Put() + } +} + +func startResourceQuotaController_kubernetes58107() { + resourceQuotaController := &ResourceQuotaController_kubernetes58107{ + queue: &Type_kubernetes58107{sync.NewCond(&sync.Mutex{})}, + missingUsageQueue: &Type_kubernetes58107{sync.NewCond(&sync.Mutex{})}, + } + + go resourceQuotaController.Run() // G2 + go resourceQuotaController.Sync() // G5 + resourceQuotaController.HelperSignals() +} + +func Kubernetes58107() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(1000 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 1000; i++ { + go startResourceQuotaController_kubernetes58107() // G1 + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes62464.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes62464.go new file mode 100644 index 00000000000000..0d07ebc4a9c451 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes62464.go @@ -0,0 +1,120 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: kubernetes + * Issue or PR : https://github.com/kubernetes/kubernetes/pull/62464 + * Buggy version: a048ca888ad27367b1a7b7377c67658920adbf5d + * fix commit-id: c1b19fce903675b82e9fdd1befcc5f5d658bfe78 + * Flaky: 8/100 + */ + +package main + +import ( + "math/rand" + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes62464", Kubernetes62464) +} + +type State_kubernetes62464 interface { + GetCPUSetOrDefault() + GetCPUSet() bool + GetDefaultCPUSet() + SetDefaultCPUSet() +} + +type stateMemory_kubernetes62464 struct { + sync.RWMutex +} + +func (s *stateMemory_kubernetes62464) GetCPUSetOrDefault() { + s.RLock() + defer s.RUnlock() + if ok := s.GetCPUSet(); ok { + return + } + s.GetDefaultCPUSet() +} + +func (s *stateMemory_kubernetes62464) GetCPUSet() bool { + runtime.Gosched() + s.RLock() + defer s.RUnlock() + + if rand.Intn(10) > 5 { + return true + } + return false +} + +func (s *stateMemory_kubernetes62464) GetDefaultCPUSet() { + s.RLock() + defer s.RUnlock() +} + +func (s *stateMemory_kubernetes62464) SetDefaultCPUSet() { + s.Lock() + runtime.Gosched() + defer s.Unlock() +} + +type staticPolicy_kubernetes62464 struct{} + +func (p *staticPolicy_kubernetes62464) RemoveContainer(s State_kubernetes62464) { + s.GetDefaultCPUSet() + s.SetDefaultCPUSet() +} + +type manager_kubernetes62464 struct { + state *stateMemory_kubernetes62464 +} + +func (m *manager_kubernetes62464) reconcileState() { + m.state.GetCPUSetOrDefault() +} + +func NewPolicyAndManager_kubernetes62464() (*staticPolicy_kubernetes62464, *manager_kubernetes62464) { + s := &stateMemory_kubernetes62464{} + m := &manager_kubernetes62464{s} + p := &staticPolicy_kubernetes62464{} + return p, m +} + +/// +/// G1 G2 +/// m.reconcileState() +/// m.state.GetCPUSetOrDefault() +/// s.RLock() +/// s.GetCPUSet() +/// p.RemoveContainer() +/// s.GetDefaultCPUSet() +/// s.SetDefaultCPUSet() +/// s.Lock() +/// s.RLock() +/// ---------------------G1,G2 deadlock--------------------- +/// + +func Kubernetes62464() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 1000; i++ { + go func() { + p, m := NewPolicyAndManager_kubernetes62464() + go m.reconcileState() + go p.RemoveContainer(m.state) + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes6632.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes6632.go new file mode 100644 index 00000000000000..a3af3b24ae81ac --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes6632.go @@ -0,0 +1,86 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: kubernetes + * Issue or PR : https://github.com/kubernetes/kubernetes/pull/6632 + * Buggy version: e597b41d939573502c8dda1dde7bf3439325fb5d + * fix commit-id: 82afb7ab1fe12cf2efceede2322d082eaf5d5adc + * Flaky: 4/100 + */ +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Kubernetes6632", Kubernetes6632) +} + +type Connection_kubernetes6632 struct { + closeChan chan bool +} + +type idleAwareFramer_kubernetes6632 struct { + resetChan chan bool + writeLock sync.Mutex + conn *Connection_kubernetes6632 +} + +func (i *idleAwareFramer_kubernetes6632) monitor() { + var resetChan = i.resetChan +Loop: + for { + select { + case <-i.conn.closeChan: + i.writeLock.Lock() + close(resetChan) + i.resetChan = nil + i.writeLock.Unlock() + break Loop + } + } +} + +func (i *idleAwareFramer_kubernetes6632) WriteFrame() { + i.writeLock.Lock() + defer i.writeLock.Unlock() + if i.resetChan == nil { + return + } + i.resetChan <- true +} + +func NewIdleAwareFramer_kubernetes6632() *idleAwareFramer_kubernetes6632 { + return &idleAwareFramer_kubernetes6632{ + resetChan: make(chan bool), + conn: &Connection_kubernetes6632{ + closeChan: make(chan bool), + }, + } +} + +func Kubernetes6632() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + i := NewIdleAwareFramer_kubernetes6632() + + go func() { // helper goroutine + i.conn.closeChan <- true + }() + go i.monitor() // G1 + go i.WriteFrame() // G2 + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes70277.go b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes70277.go new file mode 100644 index 00000000000000..ae02ec83040b99 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/kubernetes70277.go @@ -0,0 +1,97 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime/pprof" + "time" +) + +func init() { + register("Kubernetes70277", Kubernetes70277) +} + +type WaitFunc_kubernetes70277 func(done <-chan struct{}) <-chan struct{} + +type ConditionFunc_kubernetes70277 func() (done bool, err error) + +func WaitFor_kubernetes70277(wait WaitFunc_kubernetes70277, fn ConditionFunc_kubernetes70277, done <-chan struct{}) error { + c := wait(done) + for { + _, open := <-c + ok, err := fn() + if err != nil { + return err + } + if ok { + return nil + } + if !open { + break + } + } + return nil +} + +func poller_kubernetes70277(interval, timeout time.Duration) WaitFunc_kubernetes70277 { + return WaitFunc_kubernetes70277(func(done <-chan struct{}) <-chan struct{} { + ch := make(chan struct{}) + go func() { + defer close(ch) + + tick := time.NewTicker(interval) + defer tick.Stop() + + var after <-chan time.Time + if timeout != 0 { + timer := time.NewTimer(timeout) + after = timer.C + defer timer.Stop() + } + for { + select { + case <-tick.C: + select { + case ch <- struct{}{}: + default: + } + case <-after: + return + case <-done: + return + } + } + }() + + return ch + }) +} + +func Kubernetes70277() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 1000; i++ { + go func() { + stopCh := make(chan struct{}) + defer close(stopCh) + waitFunc := poller_kubernetes70277(time.Millisecond, 80*time.Millisecond) + var doneCh <-chan struct{} + + WaitFor_kubernetes70277(func(done <-chan struct{}) <-chan struct{} { + doneCh = done + return waitFunc(done) + }, func() (bool, error) { + time.Sleep(10 * time.Millisecond) + return true, nil + }, stopCh) + + <-doneCh // block here + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/main.go b/src/runtime/testdata/testgoroutineleakprofile/goker/main.go new file mode 100644 index 00000000000000..5787c1e2b2bb90 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/main.go @@ -0,0 +1,39 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import "os" + +// The number of times the main (profiling) goroutine should yield +// in order to allow the leaking goroutines to get stuck. +const yieldCount = 10 + +var cmds = map[string]func(){} + +func register(name string, f func()) { + if cmds[name] != nil { + panic("duplicate registration: " + name) + } + cmds[name] = f +} + +func registerInit(name string, f func()) { + if len(os.Args) >= 2 && os.Args[1] == name { + f() + } +} + +func main() { + if len(os.Args) < 2 { + println("usage: " + os.Args[0] + " name-of-test") + return + } + f := cmds[os.Args[1]] + if f == nil { + println("unknown function: " + os.Args[1]) + return + } + f() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby17176.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby17176.go new file mode 100644 index 00000000000000..884d077550f6b8 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby17176.go @@ -0,0 +1,68 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/17176 + * Buggy version: d295dc66521e2734390473ec1f1da8a73ad3288a + * fix commit-id: 2f16895ee94848e2d8ad72bc01968b4c88d84cb8 + * Flaky: 100/100 + */ +package main + +import ( + "errors" + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Moby17176", Moby17176) +} + +type DeviceSet_moby17176 struct { + sync.Mutex + nrDeletedDevices int +} + +func (devices *DeviceSet_moby17176) cleanupDeletedDevices() error { + devices.Lock() + if devices.nrDeletedDevices == 0 { + /// Missing devices.Unlock() + return nil + } + devices.Unlock() + return errors.New("Error") +} + +func testDevmapperLockReleasedDeviceDeletion_moby17176() { + ds := &DeviceSet_moby17176{ + nrDeletedDevices: 0, + } + ds.cleanupDeletedDevices() + doneChan := make(chan bool) + go func() { + ds.Lock() + defer ds.Unlock() + doneChan <- true + }() + + select { + case <-time.After(time.Millisecond): + case <-doneChan: + } +} +func Moby17176() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go testDevmapperLockReleasedDeviceDeletion_moby17176() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby21233.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby21233.go new file mode 100644 index 00000000000000..36017a9488cc06 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby21233.go @@ -0,0 +1,146 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/21233 + * Buggy version: cc12d2bfaae135e63b1f962ad80e6943dd995337 + * fix commit-id: 2f4aa9658408ac72a598363c6e22eadf93dbb8a7 + * Flaky:100/100 + */ +package main + +import ( + "math/rand" + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Moby21233", Moby21233) +} + +type Progress_moby21233 struct{} + +type Output_moby21233 interface { + WriteProgress(Progress_moby21233) error +} + +type chanOutput_moby21233 chan<- Progress_moby21233 + +type TransferManager_moby21233 struct { + mu sync.Mutex +} + +type Transfer_moby21233 struct { + mu sync.Mutex +} + +type Watcher_moby21233 struct { + signalChan chan struct{} + releaseChan chan struct{} + running chan struct{} +} + +func ChanOutput_moby21233(progressChan chan<- Progress_moby21233) Output_moby21233 { + return chanOutput_moby21233(progressChan) +} +func (out chanOutput_moby21233) WriteProgress(p Progress_moby21233) error { + out <- p + return nil +} +func NewTransferManager_moby21233() *TransferManager_moby21233 { + return &TransferManager_moby21233{} +} +func NewTransfer_moby21233() *Transfer_moby21233 { + return &Transfer_moby21233{} +} +func (t *Transfer_moby21233) Release(watcher *Watcher_moby21233) { + t.mu.Lock() + t.mu.Unlock() + close(watcher.releaseChan) + <-watcher.running +} +func (t *Transfer_moby21233) Watch(progressOutput Output_moby21233) *Watcher_moby21233 { + t.mu.Lock() + defer t.mu.Unlock() + lastProgress := Progress_moby21233{} + w := &Watcher_moby21233{ + releaseChan: make(chan struct{}), + signalChan: make(chan struct{}), + running: make(chan struct{}), + } + go func() { // G2 + defer func() { + close(w.running) + }() + done := false + for { + t.mu.Lock() + t.mu.Unlock() + if rand.Int31n(2) >= 1 { + progressOutput.WriteProgress(lastProgress) + } + if done { + return + } + select { + case <-w.signalChan: + case <-w.releaseChan: + done = true + } + } + }() + return w +} +func (tm *TransferManager_moby21233) Transfer(progressOutput Output_moby21233) (*Transfer_moby21233, *Watcher_moby21233) { + tm.mu.Lock() + defer tm.mu.Unlock() + t := NewTransfer_moby21233() + return t, t.Watch(progressOutput) +} + +func testTransfer_moby21233() { // G1 + tm := NewTransferManager_moby21233() + progressChan := make(chan Progress_moby21233) + progressDone := make(chan struct{}) + go func() { // G3 + time.Sleep(1 * time.Millisecond) + for p := range progressChan { /// Chan consumer + if rand.Int31n(2) >= 1 { + return + } + _ = p + } + close(progressDone) + }() + time.Sleep(1 * time.Millisecond) + ids := []string{"id1", "id2", "id3"} + xrefs := make([]*Transfer_moby21233, len(ids)) + watchers := make([]*Watcher_moby21233, len(ids)) + for i := range ids { + xrefs[i], watchers[i] = tm.Transfer(ChanOutput_moby21233(progressChan)) /// Chan producer + time.Sleep(2 * time.Millisecond) + } + + for i := range xrefs { + xrefs[i].Release(watchers[i]) + } + + close(progressChan) + <-progressDone +} + +func Moby21233() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 100; i++ { + go testTransfer_moby21233() // G1 + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby25384.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby25384.go new file mode 100644 index 00000000000000..d653731f6caea8 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby25384.go @@ -0,0 +1,59 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/25384 + * Buggy version: 58befe3081726ef74ea09198cd9488fb42c51f51 + * fix commit-id: 42360d164b9f25fb4b150ef066fcf57fa39559a7 + * Flaky: 100/100 + */ +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Moby25348", Moby25348) +} + +type plugin_moby25348 struct{} + +type Manager_moby25348 struct { + plugins []*plugin_moby25348 +} + +func (pm *Manager_moby25348) init() { + var group sync.WaitGroup + group.Add(len(pm.plugins)) + for _, p := range pm.plugins { + go func(p *plugin_moby25348) { + defer group.Done() + }(p) + group.Wait() // Block here + } +} + +func Moby25348() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { + p1 := &plugin_moby25348{} + p2 := &plugin_moby25348{} + pm := &Manager_moby25348{ + plugins: []*plugin_moby25348{p1, p2}, + } + go pm.init() + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby27782.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby27782.go new file mode 100644 index 00000000000000..7b3398fd381210 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby27782.go @@ -0,0 +1,242 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/27782 + * Buggy version: 18768fdc2e76ec6c600c8ab57d2d487ee7877794 + * fix commit-id: a69a59ffc7e3d028a72d1195c2c1535f447eaa84 + * Flaky: 2/100 + */ +package main + +import ( + "errors" + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Moby27782", Moby27782) +} + +type Event_moby27782 struct { + Op Op_moby27782 +} + +type Op_moby27782 uint32 + +const ( + Create_moby27782 Op_moby27782 = 1 << iota + Write_moby27782 + Remove_moby27782 + Rename_moby27782 + Chmod_moby27782 +) + +func newEvent(op Op_moby27782) Event_moby27782 { + return Event_moby27782{op} +} + +func (e *Event_moby27782) ignoreLinux(w *Watcher_moby27782) bool { + if e.Op != Write_moby27782 { + w.mu.Lock() + defer w.mu.Unlock() + w.cv.Broadcast() + return true + } + runtime.Gosched() + return false +} + +type Watcher_moby27782 struct { + Events chan Event_moby27782 + mu sync.Mutex // L1 + cv *sync.Cond // C1 + done chan struct{} +} + +func NewWatcher_moby27782() *Watcher_moby27782 { + w := &Watcher_moby27782{ + Events: make(chan Event_moby27782), + done: make(chan struct{}), + } + w.cv = sync.NewCond(&w.mu) + go w.readEvents() // G3 + return w +} + +func (w *Watcher_moby27782) readEvents() { + defer close(w.Events) + for { + if w.isClosed() { + return + } + event := newEvent(Write_moby27782) // MODIFY event + if !event.ignoreLinux(w) { + runtime.Gosched() + select { + case w.Events <- event: + case <-w.done: + return + } + } + } +} + +func (w *Watcher_moby27782) isClosed() bool { + select { + case <-w.done: + return true + default: + return false + } +} + +func (w *Watcher_moby27782) Close() { + if w.isClosed() { + return + } + close(w.done) +} + +func (w *Watcher_moby27782) Remove() { + w.mu.Lock() + defer w.mu.Unlock() + exists := true + for exists { + w.cv.Wait() + runtime.Gosched() + } +} + +type FileWatcher_moby27782 interface { + Events() <-chan Event_moby27782 + Remove() + Close() +} + +func New_moby27782() FileWatcher_moby27782 { + return NewEventWatcher_moby27782() +} + +func NewEventWatcher_moby27782() FileWatcher_moby27782 { + return &fsNotifyWatcher_moby27782{NewWatcher_moby27782()} +} + +type fsNotifyWatcher_moby27782 struct { + *Watcher_moby27782 +} + +func (w *fsNotifyWatcher_moby27782) Events() <-chan Event_moby27782 { + return w.Watcher_moby27782.Events +} + +func watchFile_moby27782() FileWatcher_moby27782 { + fileWatcher := New_moby27782() + return fileWatcher +} + +type LogWatcher_moby27782 struct { + closeOnce sync.Once + closeNotifier chan struct{} +} + +func (w *LogWatcher_moby27782) Close() { + w.closeOnce.Do(func() { + close(w.closeNotifier) + }) +} + +func (w *LogWatcher_moby27782) WatchClose() <-chan struct{} { + return w.closeNotifier +} + +func NewLogWatcher_moby27782() *LogWatcher_moby27782 { + return &LogWatcher_moby27782{ + closeNotifier: make(chan struct{}), + } +} + +func followLogs_moby27782(logWatcher *LogWatcher_moby27782) { + fileWatcher := watchFile_moby27782() + defer func() { + fileWatcher.Close() + }() + waitRead := func() { + runtime.Gosched() + select { + case <-fileWatcher.Events(): + case <-logWatcher.WatchClose(): + fileWatcher.Remove() + return + } + } + handleDecodeErr := func() { + waitRead() + } + handleDecodeErr() +} + +type Container_moby27782 struct { + LogDriver *JSONFileLogger_moby27782 +} + +func (container *Container_moby27782) InitializeStdio() { + if err := container.startLogging(); err != nil { + container.Reset() + } +} + +func (container *Container_moby27782) startLogging() error { + l := &JSONFileLogger_moby27782{ + readers: make(map[*LogWatcher_moby27782]struct{}), + } + container.LogDriver = l + l.ReadLogs() + return errors.New("Some error") +} + +func (container *Container_moby27782) Reset() { + if container.LogDriver != nil { + container.LogDriver.Close() + } +} + +type JSONFileLogger_moby27782 struct { + readers map[*LogWatcher_moby27782]struct{} +} + +func (l *JSONFileLogger_moby27782) ReadLogs() *LogWatcher_moby27782 { + logWatcher := NewLogWatcher_moby27782() + go l.readLogs(logWatcher) // G2 + return logWatcher +} + +func (l *JSONFileLogger_moby27782) readLogs(logWatcher *LogWatcher_moby27782) { + l.readers[logWatcher] = struct{}{} + followLogs_moby27782(logWatcher) +} + +func (l *JSONFileLogger_moby27782) Close() { + for r := range l.readers { + r.Close() + delete(l.readers, r) + } +} + +func Moby27782() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 10000; i++ { + go (&Container_moby27782{}).InitializeStdio() // G1 + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby28462.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby28462.go new file mode 100644 index 00000000000000..56467e0b56f7cc --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby28462.go @@ -0,0 +1,125 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/28462 + * Buggy version: b184bdabf7a01c4b802304ac64ac133743c484be + * fix commit-id: 89b123473774248fc3a0356dd3ce5b116cc69b29 + * Flaky: 69/100 + */ +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Moby28462", Moby28462) +} + +type State_moby28462 struct { + Health *Health_moby28462 +} + +type Container_moby28462 struct { + sync.Mutex + State *State_moby28462 +} + +func (ctr *Container_moby28462) start() { + go ctr.waitExit() +} +func (ctr *Container_moby28462) waitExit() { + +} + +type Store_moby28462 struct { + ctr *Container_moby28462 +} + +func (s *Store_moby28462) Get() *Container_moby28462 { + return s.ctr +} + +type Daemon_moby28462 struct { + containers Store_moby28462 +} + +func (d *Daemon_moby28462) StateChanged() { + c := d.containers.Get() + c.Lock() + d.updateHealthMonitorElseBranch(c) + defer c.Unlock() +} + +func (d *Daemon_moby28462) updateHealthMonitorIfBranch(c *Container_moby28462) { + h := c.State.Health + if stop := h.OpenMonitorChannel(); stop != nil { + go monitor_moby28462(c, stop) + } +} +func (d *Daemon_moby28462) updateHealthMonitorElseBranch(c *Container_moby28462) { + h := c.State.Health + h.CloseMonitorChannel() +} + +type Health_moby28462 struct { + stop chan struct{} +} + +func (s *Health_moby28462) OpenMonitorChannel() chan struct{} { + return s.stop +} + +func (s *Health_moby28462) CloseMonitorChannel() { + if s.stop != nil { + s.stop <- struct{}{} + } +} + +func monitor_moby28462(c *Container_moby28462, stop chan struct{}) { + for { + select { + case <-stop: + return + default: + handleProbeResult_moby28462(c) + } + } +} + +func handleProbeResult_moby28462(c *Container_moby28462) { + runtime.Gosched() + c.Lock() + defer c.Unlock() +} + +func NewDaemonAndContainer_moby28462() (*Daemon_moby28462, *Container_moby28462) { + c := &Container_moby28462{ + State: &State_moby28462{&Health_moby28462{make(chan struct{})}}, + } + d := &Daemon_moby28462{Store_moby28462{c}} + return d, c +} + +func Moby28462() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + d, c := NewDaemonAndContainer_moby28462() + go monitor_moby28462(c, c.State.Health.OpenMonitorChannel()) // G1 + go d.StateChanged() // G2 + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby30408.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby30408.go new file mode 100644 index 00000000000000..561e2faf576ab0 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby30408.go @@ -0,0 +1,67 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "errors" + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Moby30408", Moby30408) +} + +type Manifest_moby30408 struct { + Implements []string +} + +type Plugin_moby30408 struct { + activateWait *sync.Cond + activateErr error + Manifest *Manifest_moby30408 +} + +func (p *Plugin_moby30408) waitActive() error { + p.activateWait.L.Lock() + for !p.activated() { + p.activateWait.Wait() + } + p.activateWait.L.Unlock() + return p.activateErr +} + +func (p *Plugin_moby30408) activated() bool { + return p.Manifest != nil +} + +func testActive_moby30408(p *Plugin_moby30408) { + done := make(chan struct{}) + go func() { // G2 + p.waitActive() + close(done) + }() + <-done +} + +func Moby30408() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + go func() { // G1 + p := &Plugin_moby30408{activateWait: sync.NewCond(&sync.Mutex{})} + p.activateErr = errors.New("some junk happened") + + testActive_moby30408(p) + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby33781.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby33781.go new file mode 100644 index 00000000000000..4be50546e9be2c --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby33781.go @@ -0,0 +1,71 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/33781 + * Buggy version: 33fd3817b0f5ca4b87f0a75c2bd583b4425d392b + * fix commit-id: 67297ba0051d39be544009ba76abea14bc0be8a4 + * Flaky: 25/100 + */ + +package main + +import ( + "context" + "os" + "runtime/pprof" + "time" +) + +func init() { + register("Moby33781", Moby33781) +} + +func monitor_moby33781(stop chan bool) { + probeInterval := time.Millisecond + probeTimeout := time.Millisecond + for { + select { + case <-stop: + return + case <-time.After(probeInterval): + results := make(chan bool) + ctx, cancelProbe := context.WithTimeout(context.Background(), probeTimeout) + go func() { // G3 + results <- true + close(results) + }() + select { + case <-stop: + // results should be drained here + cancelProbe() + return + case <-results: + cancelProbe() + case <-ctx.Done(): + cancelProbe() + <-results + } + } + } +} + +func Moby33781() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + for i := 0; i < 100; i++ { + go func(i int) { + stop := make(chan bool) + go monitor_moby33781(stop) // G1 + go func() { // G2 + time.Sleep(time.Duration(i) * time.Millisecond) + stop <- true + }() + }(i) + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby36114.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby36114.go new file mode 100644 index 00000000000000..577c81651a0668 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby36114.go @@ -0,0 +1,53 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/36114 + * Buggy version: 6d4d3c52ae7c3f910bfc7552a2a673a8338e5b9f + * fix commit-id: a44fcd3d27c06aaa60d8d1cbce169f0d982e74b1 + * Flaky: 100/100 + */ +package main + +import ( + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Moby36114", Moby36114) +} + +type serviceVM_moby36114 struct { + sync.Mutex +} + +func (svm *serviceVM_moby36114) hotAddVHDsAtStart() { + svm.Lock() + defer svm.Unlock() + svm.hotRemoveVHDsAtStart() +} + +func (svm *serviceVM_moby36114) hotRemoveVHDsAtStart() { + svm.Lock() + defer svm.Unlock() +} + +func Moby36114() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 100; i++ { + go func() { + s := &serviceVM_moby36114{} + go s.hotAddVHDsAtStart() + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby4951.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby4951.go new file mode 100644 index 00000000000000..7f0497648cf606 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby4951.go @@ -0,0 +1,101 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/4951 + * Buggy version: 81f148be566ab2b17810ad4be61a5d8beac8330f + * fix commit-id: 2ffef1b7eb618162673c6ffabccb9ca57c7dfce3 + * Flaky: 100/100 + */ +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Moby4951", Moby4951) +} + +type DeviceSet_moby4951 struct { + sync.Mutex + infos map[string]*DevInfo_moby4951 + nrDeletedDevices int +} + +func (devices *DeviceSet_moby4951) DeleteDevice(hash string) { + devices.Lock() + defer devices.Unlock() + + info := devices.lookupDevice(hash) + + info.lock.Lock() + runtime.Gosched() + defer info.lock.Unlock() + + devices.deleteDevice(info) +} + +func (devices *DeviceSet_moby4951) lookupDevice(hash string) *DevInfo_moby4951 { + existing, ok := devices.infos[hash] + if !ok { + return nil + } + return existing +} + +func (devices *DeviceSet_moby4951) deleteDevice(info *DevInfo_moby4951) { + devices.removeDeviceAndWait(info.Name()) +} + +func (devices *DeviceSet_moby4951) removeDeviceAndWait(devname string) { + /// remove devices by devname + devices.Unlock() + time.Sleep(300 * time.Nanosecond) + devices.Lock() +} + +type DevInfo_moby4951 struct { + lock sync.Mutex + name string +} + +func (info *DevInfo_moby4951) Name() string { + return info.name +} + +func NewDeviceSet_moby4951() *DeviceSet_moby4951 { + devices := &DeviceSet_moby4951{ + infos: make(map[string]*DevInfo_moby4951), + } + info1 := &DevInfo_moby4951{ + name: "info1", + } + info2 := &DevInfo_moby4951{ + name: "info2", + } + devices.infos[info1.name] = info1 + devices.infos[info2.name] = info2 + return devices +} + +func Moby4951() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + go func() { + ds := NewDeviceSet_moby4951() + /// Delete devices by the same info + go ds.DeleteDevice("info1") + go ds.DeleteDevice("info1") + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby7559.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby7559.go new file mode 100644 index 00000000000000..212f65b1f3f2c6 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby7559.go @@ -0,0 +1,55 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +/* + * Project: moby + * Issue or PR : https://github.com/moby/moby/pull/7559 + * Buggy version: 64579f51fcb439c36377c0068ccc9a007b368b5a + * fix commit-id: 6cbb8e070d6c3a66bf48fbe5cbf689557eee23db + * Flaky: 100/100 + */ +package main + +import ( + "net" + "os" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Moby7559", Moby7559) +} + +type UDPProxy_moby7559 struct { + connTrackLock sync.Mutex +} + +func (proxy *UDPProxy_moby7559) Run() { + for i := 0; i < 2; i++ { + proxy.connTrackLock.Lock() + _, err := net.DialUDP("udp", nil, nil) + if err != nil { + continue + /// Missing unlock here + } + if i == 0 { + break + } + } + proxy.connTrackLock.Unlock() +} + +func Moby7559() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 20; i++ { + go (&UDPProxy_moby7559{}).Run() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/serving2137.go b/src/runtime/testdata/testgoroutineleakprofile/goker/serving2137.go new file mode 100644 index 00000000000000..49905315a01b4c --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/serving2137.go @@ -0,0 +1,122 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +func init() { + register("Serving2137", Serving2137) +} + +type token_serving2137 struct{} + +type request_serving2137 struct { + lock *sync.Mutex + accepted chan bool +} + +type Breaker_serving2137 struct { + pendingRequests chan token_serving2137 + activeRequests chan token_serving2137 +} + +func (b *Breaker_serving2137) Maybe(thunk func()) bool { + var t token_serving2137 + select { + default: + // Pending request queue is full. Report failure. + return false + case b.pendingRequests <- t: + // Pending request has capacity. + // Wait for capacity in the active queue. + b.activeRequests <- t + // Defer releasing capacity in the active and pending request queue. + defer func() { + <-b.activeRequests + runtime.Gosched() + <-b.pendingRequests + }() + // Do the thing. + thunk() + // Report success + return true + } +} + +func (b *Breaker_serving2137) concurrentRequest() request_serving2137 { + r := request_serving2137{lock: &sync.Mutex{}, accepted: make(chan bool, 1)} + r.lock.Lock() + var start sync.WaitGroup + start.Add(1) + go func() { // G2, G3 + start.Done() + runtime.Gosched() + ok := b.Maybe(func() { + // Will block on locked mutex. + r.lock.Lock() + runtime.Gosched() + r.lock.Unlock() + }) + r.accepted <- ok + }() + start.Wait() // Ensure that the go func has had a chance to execute. + return r +} + +// Perform n requests against the breaker, returning mutexes for each +// request which succeeded, and a slice of bools for all requests. +func (b *Breaker_serving2137) concurrentRequests(n int) []request_serving2137 { + requests := make([]request_serving2137, n) + for i := range requests { + requests[i] = b.concurrentRequest() + } + return requests +} + +func NewBreaker_serving2137(queueDepth, maxConcurrency int32) *Breaker_serving2137 { + return &Breaker_serving2137{ + pendingRequests: make(chan token_serving2137, queueDepth+maxConcurrency), + activeRequests: make(chan token_serving2137, maxConcurrency), + } +} + +func unlock_serving2137(req request_serving2137) { + req.lock.Unlock() + runtime.Gosched() + // Verify that function has completed + ok := <-req.accepted + runtime.Gosched() + // Requeue for next usage + req.accepted <- ok +} + +func unlockAll_serving2137(requests []request_serving2137) { + for _, lc := range requests { + unlock_serving2137(lc) + } +} + +func Serving2137() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(100 * time.Millisecond) + prof.WriteTo(os.Stdout, 2) + }() + + for i := 0; i < 1000; i++ { + go func() { + b := NewBreaker_serving2137(1, 1) + + locks := b.concurrentRequests(2) // G1 + unlockAll_serving2137(locks) + }() + } +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/syncthing4829.go b/src/runtime/testdata/testgoroutineleakprofile/goker/syncthing4829.go new file mode 100644 index 00000000000000..7967db7cfe083f --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/syncthing4829.go @@ -0,0 +1,87 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Syncthing4829", Syncthing4829) +} + +type Address_syncthing4829 int + +type Mapping_syncthing4829 struct { + mut sync.RWMutex // L2 + + extAddresses map[string]Address_syncthing4829 +} + +func (m *Mapping_syncthing4829) clearAddresses() { + m.mut.Lock() // L2 + var removed []Address_syncthing4829 + for id, addr := range m.extAddresses { + removed = append(removed, addr) + delete(m.extAddresses, id) + } + if len(removed) > 0 { + m.notify(nil, removed) + } + m.mut.Unlock() // L2 +} + +func (m *Mapping_syncthing4829) notify(added, remove []Address_syncthing4829) { + m.mut.RLock() // L2 + m.mut.RUnlock() // L2 +} + +type Service_syncthing4829 struct { + mut sync.RWMutex // L1 + + mappings []*Mapping_syncthing4829 +} + +func (s *Service_syncthing4829) NewMapping() *Mapping_syncthing4829 { + mapping := &Mapping_syncthing4829{ + extAddresses: make(map[string]Address_syncthing4829), + } + s.mut.Lock() // L1 + s.mappings = append(s.mappings, mapping) + s.mut.Unlock() // L1 + return mapping +} + +func (s *Service_syncthing4829) RemoveMapping(mapping *Mapping_syncthing4829) { + s.mut.Lock() // L1 + defer s.mut.Unlock() // L1 + for _, existing := range s.mappings { + if existing == mapping { + mapping.clearAddresses() + } + } +} + +func Syncthing4829() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + + go func() { // G1 + natSvc := &Service_syncthing4829{} + m := natSvc.NewMapping() + m.extAddresses["test"] = 0 + + natSvc.RemoveMapping(m) + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/syncthing5795.go b/src/runtime/testdata/testgoroutineleakprofile/goker/syncthing5795.go new file mode 100644 index 00000000000000..e25494a688dd5c --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/goker/syncthing5795.go @@ -0,0 +1,103 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a MIT +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" +) + +func init() { + register("Syncthing5795", Syncthing5795) +} + +type message_syncthing5795 interface{} + +type ClusterConfig_syncthing5795 struct{} + +type Model_syncthing5795 interface { + ClusterConfig(message_syncthing5795) +} + +type TestModel_syncthing5795 struct { + ccFn func() +} + +func (t *TestModel_syncthing5795) ClusterConfig(msg message_syncthing5795) { + if t.ccFn != nil { + t.ccFn() + } +} + +type Connection_syncthing5795 interface { + Start() + Close() +} + +type rawConnection_syncthing5795 struct { + receiver Model_syncthing5795 + + inbox chan message_syncthing5795 + dispatcherLoopStopped chan struct{} + closed chan struct{} + closeOnce sync.Once +} + +func (c *rawConnection_syncthing5795) Start() { + go c.dispatcherLoop() // G2 +} + +func (c *rawConnection_syncthing5795) dispatcherLoop() { + defer close(c.dispatcherLoopStopped) + var msg message_syncthing5795 + for { + select { + case msg = <-c.inbox: + case <-c.closed: + return + } + switch msg := msg.(type) { + case *ClusterConfig_syncthing5795: + c.receiver.ClusterConfig(msg) + default: + return + } + } +} + +func (c *rawConnection_syncthing5795) Close() { + c.closeOnce.Do(func() { + close(c.closed) + <-c.dispatcherLoopStopped + }) +} + +func Syncthing5795() { + prof := pprof.Lookup("goroutineleak") + defer func() { + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) + }() + go func() { // G1 + m := &TestModel_syncthing5795{} + c := &rawConnection_syncthing5795{ + dispatcherLoopStopped: make(chan struct{}), + closed: make(chan struct{}), + inbox: make(chan message_syncthing5795), + receiver: m, + } + m.ccFn = c.Close + + c.Start() + c.inbox <- &ClusterConfig_syncthing5795{} + + <-c.dispatcherLoopStopped + }() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/main.go b/src/runtime/testdata/testgoroutineleakprofile/main.go new file mode 100644 index 00000000000000..5787c1e2b2bb90 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/main.go @@ -0,0 +1,39 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import "os" + +// The number of times the main (profiling) goroutine should yield +// in order to allow the leaking goroutines to get stuck. +const yieldCount = 10 + +var cmds = map[string]func(){} + +func register(name string, f func()) { + if cmds[name] != nil { + panic("duplicate registration: " + name) + } + cmds[name] = f +} + +func registerInit(name string, f func()) { + if len(os.Args) >= 2 && os.Args[1] == name { + f() + } +} + +func main() { + if len(os.Args) < 2 { + println("usage: " + os.Args[0] + " name-of-test") + return + } + f := cmds[os.Args[1]] + if f == nil { + println("unknown function: " + os.Args[1]) + return + } + f() +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/simple.go b/src/runtime/testdata/testgoroutineleakprofile/simple.go new file mode 100644 index 00000000000000..b8172cd6df8aa7 --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/simple.go @@ -0,0 +1,253 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import ( + "os" + "runtime" + "runtime/pprof" + "sync" +) + +// This is a set of micro-tests with obvious goroutine leaks that +// ensures goroutine leak detection works. +// +// Tests in this file are not flaky iff. run with GOMAXPROCS=1. +// The main goroutine forcefully yields via `runtime.Gosched()` before +// running the profiler. This moves them to the back of the run queue, +// allowing the leaky goroutines to be scheduled beforehand and get stuck. + +func init() { + register("NilRecv", NilRecv) + register("NilSend", NilSend) + register("SelectNoCases", SelectNoCases) + register("ChanRecv", ChanRecv) + register("ChanSend", ChanSend) + register("Select", Select) + register("WaitGroup", WaitGroup) + register("MutexStack", MutexStack) + register("MutexHeap", MutexHeap) + register("RWMutexRLock", RWMutexRLock) + register("RWMutexLock", RWMutexLock) + register("Cond", Cond) + register("Mixed", Mixed) + register("NoLeakGlobal", NoLeakGlobal) +} + +func NilRecv() { + prof := pprof.Lookup("goroutineleak") + go func() { + var c chan int + <-c + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func NilSend() { + prof := pprof.Lookup("goroutineleak") + go func() { + var c chan int + c <- 0 + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func ChanRecv() { + prof := pprof.Lookup("goroutineleak") + go func() { + <-make(chan int) + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func SelectNoCases() { + prof := pprof.Lookup("goroutineleak") + go func() { + select {} + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func ChanSend() { + prof := pprof.Lookup("goroutineleak") + go func() { + make(chan int) <- 0 + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func Select() { + prof := pprof.Lookup("goroutineleak") + go func() { + select { + case make(chan int) <- 0: + case <-make(chan int): + } + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func WaitGroup() { + prof := pprof.Lookup("goroutineleak") + go func() { + var wg sync.WaitGroup + wg.Add(1) + wg.Wait() + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func MutexStack() { + prof := pprof.Lookup("goroutineleak") + for i := 0; i < 1000; i++ { + go func() { + var mu sync.Mutex + mu.Lock() + mu.Lock() + panic("should not be reached") + }() + } + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func MutexHeap() { + prof := pprof.Lookup("goroutineleak") + for i := 0; i < 1000; i++ { + go func() { + mu := &sync.Mutex{} + go func() { + mu.Lock() + mu.Lock() + panic("should not be reached") + }() + }() + } + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func RWMutexRLock() { + prof := pprof.Lookup("goroutineleak") + go func() { + mu := &sync.RWMutex{} + mu.Lock() + mu.RLock() + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func RWMutexLock() { + prof := pprof.Lookup("goroutineleak") + go func() { + mu := &sync.RWMutex{} + mu.Lock() + mu.Lock() + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func Cond() { + prof := pprof.Lookup("goroutineleak") + go func() { + cond := sync.NewCond(&sync.Mutex{}) + cond.L.Lock() + cond.Wait() + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +func Mixed() { + prof := pprof.Lookup("goroutineleak") + go func() { + ch := make(chan int) + wg := sync.WaitGroup{} + wg.Add(1) + go func() { + ch <- 0 + wg.Done() + panic("should not be reached") + }() + wg.Wait() + <-ch + panic("should not be reached") + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} + +var ch = make(chan int) + +// No leak should be reported by this test +func NoLeakGlobal() { + prof := pprof.Lookup("goroutineleak") + go func() { + <-ch + }() + // Yield several times to allow the child goroutine to run. + for i := 0; i < yieldCount; i++ { + runtime.Gosched() + } + prof.WriteTo(os.Stdout, 2) +} diff --git a/src/runtime/testdata/testgoroutineleakprofile/stresstests.go b/src/runtime/testdata/testgoroutineleakprofile/stresstests.go new file mode 100644 index 00000000000000..64b535f51c87ef --- /dev/null +++ b/src/runtime/testdata/testgoroutineleakprofile/stresstests.go @@ -0,0 +1,89 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import ( + "io" + "os" + "runtime" + "runtime/pprof" + "sync" + "time" +) + +const spawnGCMaxDepth = 5 + +func init() { + register("SpawnGC", SpawnGC) + register("DaisyChain", DaisyChain) +} + +func spawnGC(i int) { + prof := pprof.Lookup("goroutineleak") + if i == 0 { + return + } + wg := &sync.WaitGroup{} + wg.Add(i + 1) + go func() { + wg.Done() + <-make(chan int) + }() + for j := 0; j < i; j++ { + go func() { + wg.Done() + spawnGC(i - 1) + }() + } + wg.Wait() + runtime.Gosched() + if i == spawnGCMaxDepth { + prof.WriteTo(os.Stdout, 2) + } else { + // We want to concurrently trigger the profile in order to concurrently run + // the GC, but we don't want to stream all the profiles to standard output. + // + // Only output the profile for the root call to spawnGC, and otherwise stream + // the profile outputs to /dev/null to avoid jumbling. + prof.WriteTo(io.Discard, 2) + } +} + +// SpawnGC spawns a tree of goroutine leaks and calls the goroutine leak profiler +// for each node in the tree. It is supposed to stress the goroutine leak profiler +// under a heavily concurrent workload. +func SpawnGC() { + spawnGC(spawnGCMaxDepth) +} + +// DaisyChain spawns a daisy-chain of runnable goroutines. +// +// Each goroutine in the chain creates a new channel and goroutine. +// +// This illustrates a pathological worstcase for the goroutine leak GC complexity, +// as opposed to the regular GC, which is not negatively affected by this pattern. +func DaisyChain() { + prof := pprof.Lookup("goroutineleak") + defer func() { + time.Sleep(time.Second) + prof.WriteTo(os.Stdout, 2) + }() + var chain func(i int, ch chan struct{}) + chain = func(i int, ch chan struct{}) { + if i <= 0 { + go func() { + time.Sleep(time.Hour) + ch <- struct{}{} + }() + return + } + ch2 := make(chan struct{}) + go chain(i-1, ch2) + <-ch2 + ch <- struct{}{} + } + // The channel buffer avoids goroutine leaks. + go chain(1000, make(chan struct{}, 1)) +} diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go index 53f41bca0b11ff..8882c306edb736 100644 --- a/src/runtime/traceback.go +++ b/src/runtime/traceback.go @@ -1206,6 +1206,7 @@ var gStatusStrings = [...]string{ _Gwaiting: "waiting", _Gdead: "dead", _Gcopystack: "copystack", + _Gleaked: "leaked", _Gpreempted: "preempted", } @@ -1226,7 +1227,7 @@ func goroutineheader(gp *g) { } // Override. - if gpstatus == _Gwaiting && gp.waitreason != waitReasonZero { + if (gpstatus == _Gwaiting || gpstatus == _Gleaked) && gp.waitreason != waitReasonZero { status = gp.waitreason.String() } @@ -1245,6 +1246,9 @@ func goroutineheader(gp *g) { } } print(" [", status) + if gpstatus == _Gleaked { + print(" (leaked)") + } if isScan { print(" (scan)") } diff --git a/src/runtime/tracestatus.go b/src/runtime/tracestatus.go index 03ec81fc0262a1..8b5eafd170f488 100644 --- a/src/runtime/tracestatus.go +++ b/src/runtime/tracestatus.go @@ -122,7 +122,7 @@ func goStatusToTraceGoStatus(status uint32, wr waitReason) tracev2.GoStatus { tgs = tracev2.GoRunning case _Gsyscall: tgs = tracev2.GoSyscall - case _Gwaiting, _Gpreempted: + case _Gwaiting, _Gpreempted, _Gleaked: // There are a number of cases where a G might end up in // _Gwaiting but it's actually running in a non-preemptive // state but needs to present itself as preempted to the From 707454b41fa1fea7e0286b1370dea47d3422b2cb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20Mart=C3=AD?= Date: Sat, 30 Aug 2025 21:13:12 +0100 Subject: [PATCH 035/229] cmd/go: update `go help mod edit` with the tool and ignore sections The types were added to the docs, but not the fields in GoMod. While here, I was initially confused about what is the top-level type given that `type Module` comes first. Move `type GoMod` to the top as it is the actual top-level type. Change-Id: I1270154837501f5c7f5b21959b2841fd4ac808d0 Reviewed-on: https://go-review.googlesource.com/c/go/+/700116 Reviewed-by: Sean Liao Reviewed-by: Carlos Amedee LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Matloob Reviewed-by: Junyang Shao --- src/cmd/go/alldocs.go | 12 +++++++----- src/cmd/go/internal/modcmd/edit.go | 12 +++++++----- 2 files changed, 14 insertions(+), 10 deletions(-) diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go index f1e1b1c333542c..19b48f0579bb29 100644 --- a/src/cmd/go/alldocs.go +++ b/src/cmd/go/alldocs.go @@ -1280,11 +1280,6 @@ // The -json flag prints the final go.mod file in JSON format instead of // writing it back to go.mod. The JSON output corresponds to these Go types: // -// type Module struct { -// Path string -// Version string -// } -// // type GoMod struct { // Module ModPath // Go string @@ -1294,6 +1289,13 @@ // Exclude []Module // Replace []Replace // Retract []Retract +// Tool []Tool +// Ignore []Ignore +// } +// +// type Module struct { +// Path string +// Version string // } // // type ModPath struct { diff --git a/src/cmd/go/internal/modcmd/edit.go b/src/cmd/go/internal/modcmd/edit.go index aafd9752a8e487..041b4432bfd4f0 100644 --- a/src/cmd/go/internal/modcmd/edit.go +++ b/src/cmd/go/internal/modcmd/edit.go @@ -104,11 +104,6 @@ writing it back to go.mod. The -json flag prints the final go.mod file in JSON format instead of writing it back to go.mod. The JSON output corresponds to these Go types: - type Module struct { - Path string - Version string - } - type GoMod struct { Module ModPath Go string @@ -118,6 +113,13 @@ writing it back to go.mod. The JSON output corresponds to these Go types: Exclude []Module Replace []Replace Retract []Retract + Tool []Tool + Ignore []Ignore + } + + type Module struct { + Path string + Version string } type ModPath struct { From f03c392295cfd57c29c92fcc300181f8016cf5ac Mon Sep 17 00:00:00 2001 From: qmuntal Date: Wed, 1 Oct 2025 10:59:53 +0200 Subject: [PATCH 036/229] runtime: fix aix/ppc64 library initialization AIX sets the argc and argv parameters in R14 and R15, but _rt0_ppc64x_lib expects them to be in R3 and R4. Also, call reginit in _rt0_ppc64x_lib. These issues were oversights from CL 706395 which went unnoticed because there if no LUCI aix/ppc64 builder (see #67299). Change-Id: I93a2798739935fbcead3e6162b4b90db7e740aa5 Reviewed-on: https://go-review.googlesource.com/c/go/+/708255 Reviewed-by: Carlos Amedee LUCI-TryBot-Result: Go LUCI Reviewed-by: Junyang Shao Reviewed-by: Paul Murphy --- src/runtime/asm_ppc64x.s | 3 +++ src/runtime/rt0_aix_ppc64.s | 2 ++ 2 files changed, 5 insertions(+) diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s index 3fbf11b5e9a2ad..b42e0b62f850ff 100644 --- a/src/runtime/asm_ppc64x.s +++ b/src/runtime/asm_ppc64x.s @@ -21,6 +21,9 @@ TEXT _rt0_ppc64x_lib(SB),NOSPLIT|NOFRAME,$0 MOVD R4, _rt0_ppc64x_lib_argv<>(SB) // Synchronous initialization. + MOVD $runtime·reginit(SB), R12 + MOVD R12, CTR + BL (CTR) MOVD $runtime·libpreinit(SB), R12 MOVD R12, CTR BL (CTR) diff --git a/src/runtime/rt0_aix_ppc64.s b/src/runtime/rt0_aix_ppc64.s index 32f8c72156c9ee..518fcb3b88d670 100644 --- a/src/runtime/rt0_aix_ppc64.s +++ b/src/runtime/rt0_aix_ppc64.s @@ -42,4 +42,6 @@ TEXT _main(SB),NOSPLIT,$-8 BR (CTR) TEXT _rt0_ppc64_aix_lib(SB),NOSPLIT,$0 + MOVD R14, R3 // argc + MOVD R15, R4 // argv JMP _rt0_ppc64x_lib(SB) From 0e4e2e68323df08d9e4c876e5abc5b549bd247f5 Mon Sep 17 00:00:00 2001 From: Michael Anthony Knyszek Date: Thu, 2 Oct 2025 19:15:34 +0000 Subject: [PATCH 037/229] runtime: skip TestGoroutineLeakProfile under mayMoreStackPreempt This may be the long-term fix, but we first need to understand if this just makes the tests flaky, or if it's revealing an actual underlying issue. I'm leaning toward the former. If it is the former, ideally we just make the tests robust (wait longer, maybe?). For now, this change will make the longtest builders OK again. For #75729. Change-Id: If9b30107d04a8e5af5670850add3a53f9471eec6 Reviewed-on: https://go-review.googlesource.com/c/go/+/708715 Reviewed-by: Roland Shoemaker Reviewed-by: Michael Pratt Auto-Submit: Michael Knyszek LUCI-TryBot-Result: Go LUCI Reviewed-by: Carlos Amedee --- src/runtime/goroutineleakprofile_test.go | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/src/runtime/goroutineleakprofile_test.go b/src/runtime/goroutineleakprofile_test.go index 9857d725deef32..6e26bcab132831 100644 --- a/src/runtime/goroutineleakprofile_test.go +++ b/src/runtime/goroutineleakprofile_test.go @@ -6,12 +6,20 @@ package runtime_test import ( "fmt" + "internal/testenv" + "os" "regexp" "strings" "testing" ) func TestGoroutineLeakProfile(t *testing.T) { + if strings.Contains(os.Getenv("GOFLAGS"), "mayMoreStackPreempt") { + // Some tests have false negatives under mayMoreStackPreempt. This may be a test-only issue, + // but needs more investigation. + testenv.SkipFlaky(t, 75729) + } + // Goroutine leak test case. // // Test cases can be configured with test name, the name of the entry point function, @@ -356,7 +364,7 @@ func TestGoroutineLeakProfile(t *testing.T) { `\(\*Page_hugo5379\)\.initContent\.func1\.1\(.* \[sync\.Mutex\.Lock\]`, `pageRenderer_hugo5379\(.* \[sync\.Mutex\.Lock\]`, `Hugo5379\.func2\(.* \[sync\.WaitGroup\.Wait\]`, - ), + ), makeFlakyTest("Istio16224", `Istio16224\.func2\(.* \[sync\.Mutex\.Lock\]`, `\(\*controller_istio16224\)\.Run\(.* \[chan send\]`, From 4008e07080ef215e46f48e5e2f6b5d37d6d9cb9f Mon Sep 17 00:00:00 2001 From: Damien Neil Date: Thu, 2 Oct 2025 10:45:01 -0700 Subject: [PATCH 038/229] io/fs: move path name documentation up to the package doc comment Perhaps surprisingly to users, io/fs path names are slash-separated. Move the documentation for path names up to the top of the package rather than burying it in the ValidPath documentation. Change-Id: Id338df07c74a16be74c687ac4c45e0513ee40a8c Reviewed-on: https://go-review.googlesource.com/c/go/+/708616 LUCI-TryBot-Result: Go LUCI Reviewed-by: Alan Donovan Auto-Submit: Damien Neil --- src/io/fs/fs.go | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/src/io/fs/fs.go b/src/io/fs/fs.go index 8f693f2574a5b6..fca07b818c9a3b 100644 --- a/src/io/fs/fs.go +++ b/src/io/fs/fs.go @@ -6,6 +6,19 @@ // A file system can be provided by the host operating system // but also by other packages. // +// # Path Names +// +// The interfaces in this package all operate on the same +// path name syntax, regardless of the host operating system. +// +// Path names are UTF-8-encoded, +// unrooted, slash-separated sequences of path elements, like “x/y/z”. +// Path names must not contain an element that is “.” or “..” or the empty string, +// except for the special case that the name "." may be used for the root directory. +// Paths must not start or end with a slash: “/x” and “x/” are invalid. +// +// # Testing +// // See the [testing/fstest] package for support with testing // implementations of file systems. package fs @@ -41,16 +54,13 @@ type FS interface { // ValidPath reports whether the given path name // is valid for use in a call to Open. // -// Path names passed to open are UTF-8-encoded, -// unrooted, slash-separated sequences of path elements, like “x/y/z”. -// Path names must not contain an element that is “.” or “..” or the empty string, -// except for the special case that the name "." may be used for the root directory. -// Paths must not start or end with a slash: “/x” and “x/” are invalid. -// // Note that paths are slash-separated on all systems, even Windows. // Paths containing other characters such as backslash and colon // are accepted as valid, but those characters must never be // interpreted by an [FS] implementation as path element separators. +// See the [Path Names] section for more details. +// +// [Path Names]: https://pkg.go.dev/io/fs#hdr-Path_Names func ValidPath(name string) bool { if !utf8.ValidString(name) { return false From bbdff9e8e1fca772a13acb0c4c7828cfe246d403 Mon Sep 17 00:00:00 2001 From: "Nicholas S. Husin" Date: Thu, 2 Oct 2025 12:41:25 -0400 Subject: [PATCH 039/229] net/http: update bundled x/net/http2 and delete obsolete http2inTests http2inTests is no longer needed after go.dev/cl/708135 and should be deleted. To prevent errors in future vendored dependency updates, h2_bundle.go is also updated together in this change. Change-Id: I7b8c3f6854203fab4ec639a2a268df0cd2b1dee7 Reviewed-on: https://go-review.googlesource.com/c/go/+/708595 Reviewed-by: Damien Neil Reviewed-by: Nicholas Husin LUCI-TryBot-Result: Go LUCI --- src/go.mod | 2 +- src/go.sum | 4 +- src/net/http/h2_bundle.go | 415 ++++++++++++++---- src/net/http/http2_test.go | 12 - .../http/internal/httpcommon/httpcommon.go | 4 +- src/net/http/socks_bundle.go | 2 +- .../golang.org/x/net/nettest/conntest.go | 6 +- src/vendor/modules.txt | 2 +- 8 files changed, 336 insertions(+), 111 deletions(-) delete mode 100644 src/net/http/http2_test.go diff --git a/src/go.mod b/src/go.mod index 4b400fe87189d1..f134f0c7b571da 100644 --- a/src/go.mod +++ b/src/go.mod @@ -4,7 +4,7 @@ go 1.26 require ( golang.org/x/crypto v0.42.0 - golang.org/x/net v0.44.0 + golang.org/x/net v0.44.1-0.20251002015445-edb764c2296f ) require ( diff --git a/src/go.sum b/src/go.sum index c90970a9cbaaad..f24bea029a2239 100644 --- a/src/go.sum +++ b/src/go.sum @@ -1,7 +1,7 @@ golang.org/x/crypto v0.42.0 h1:chiH31gIWm57EkTXpwnqf8qeuMUi0yekh6mT2AvFlqI= golang.org/x/crypto v0.42.0/go.mod h1:4+rDnOTJhQCx2q7/j6rAN5XDw8kPjeaXEUR2eL94ix8= -golang.org/x/net v0.44.0 h1:evd8IRDyfNBMBTTY5XRF1vaZlD+EmWx6x8PkhR04H/I= -golang.org/x/net v0.44.0/go.mod h1:ECOoLqd5U3Lhyeyo/QDCEVQ4sNgYsqvCZ722XogGieY= +golang.org/x/net v0.44.1-0.20251002015445-edb764c2296f h1:vNklv+oJQSYNGsWXHoCPi2MHMcpj9/Q7aBhvvfnJvGg= +golang.org/x/net v0.44.1-0.20251002015445-edb764c2296f/go.mod h1:ECOoLqd5U3Lhyeyo/QDCEVQ4sNgYsqvCZ722XogGieY= golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k= golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks= golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk= diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go index 3abd7476f04e73..f09e102efb7b1c 100644 --- a/src/net/http/h2_bundle.go +++ b/src/net/http/h2_bundle.go @@ -1047,6 +1047,7 @@ func http2shouldRetryDial(call *http2dialCall, req *Request) bool { // - If the resulting value is zero or out of range, use a default. type http2http2Config struct { MaxConcurrentStreams uint32 + StrictMaxConcurrentRequests bool MaxDecoderHeaderTableSize uint32 MaxEncoderHeaderTableSize uint32 MaxReadFrameSize uint32 @@ -1084,12 +1085,13 @@ func http2configFromServer(h1 *Server, h2 *http2Server) http2http2Config { // (the net/http Transport). func http2configFromTransport(h2 *http2Transport) http2http2Config { conf := http2http2Config{ - MaxEncoderHeaderTableSize: h2.MaxEncoderHeaderTableSize, - MaxDecoderHeaderTableSize: h2.MaxDecoderHeaderTableSize, - MaxReadFrameSize: h2.MaxReadFrameSize, - SendPingTimeout: h2.ReadIdleTimeout, - PingTimeout: h2.PingTimeout, - WriteByteTimeout: h2.WriteByteTimeout, + StrictMaxConcurrentRequests: h2.StrictMaxConcurrentStreams, + MaxEncoderHeaderTableSize: h2.MaxEncoderHeaderTableSize, + MaxDecoderHeaderTableSize: h2.MaxDecoderHeaderTableSize, + MaxReadFrameSize: h2.MaxReadFrameSize, + SendPingTimeout: h2.ReadIdleTimeout, + PingTimeout: h2.PingTimeout, + WriteByteTimeout: h2.WriteByteTimeout, } // Unlike most config fields, where out-of-range values revert to the default, @@ -1148,6 +1150,9 @@ func http2fillNetHTTPConfig(conf *http2http2Config, h2 *HTTP2Config) { if h2.MaxConcurrentStreams != 0 { conf.MaxConcurrentStreams = uint32(h2.MaxConcurrentStreams) } + if http2http2ConfigStrictMaxConcurrentRequests(h2) { + conf.StrictMaxConcurrentRequests = true + } if h2.MaxEncoderHeaderTableSize != 0 { conf.MaxEncoderHeaderTableSize = uint32(h2.MaxEncoderHeaderTableSize) } @@ -1183,6 +1188,10 @@ func http2fillNetHTTPConfig(conf *http2http2Config, h2 *HTTP2Config) { } } +func http2http2ConfigStrictMaxConcurrentRequests(h2 *HTTP2Config) bool { + return h2.StrictMaxConcurrentRequests +} + // Buffer chunks are allocated from a pool to reduce pressure on GC. // The maximum wasted space per dataBuffer is 2x the largest size class, // which happens when the dataBuffer has multiple chunks and there is @@ -1900,7 +1909,7 @@ func (fr *http2Framer) maxHeaderListSize() uint32 { func (f *http2Framer) startWrite(ftype http2FrameType, flags http2Flags, streamID uint32) { // Write the FrameHeader. f.wbuf = append(f.wbuf[:0], - 0, // 3 bytes of length, filled in in endWrite + 0, // 3 bytes of length, filled in endWrite 0, 0, byte(ftype), @@ -2708,6 +2717,15 @@ type http2PriorityFrame struct { http2PriorityParam } +var http2defaultRFC9218Priority = http2PriorityParam{ + incremental: 0, + urgency: 3, +} + +// Note that HTTP/2 has had two different prioritization schemes, and +// PriorityParam struct below is a superset of both schemes. The exported +// symbols are from RFC 7540 and the non-exported ones are from RFC 9218. + // PriorityParam are the stream prioritzation parameters. type http2PriorityParam struct { // StreamDep is a 31-bit stream identifier for the @@ -2723,6 +2741,20 @@ type http2PriorityParam struct { // the spec, "Add one to the value to obtain a weight between // 1 and 256." Weight uint8 + + // "The urgency (u) parameter value is Integer (see Section 3.3.1 of + // [STRUCTURED-FIELDS]), between 0 and 7 inclusive, in descending order of + // priority. The default is 3." + urgency uint8 + + // "The incremental (i) parameter value is Boolean (see Section 3.3.6 of + // [STRUCTURED-FIELDS]). It indicates if an HTTP response can be processed + // incrementally, i.e., provide some meaningful output as chunks of the + // response arrive." + // + // We use uint8 (i.e. 0 is false, 1 is true) instead of bool so we can + // avoid unnecessary type conversions and because either type takes 1 byte. + incremental uint8 } func (p http2PriorityParam) IsZero() bool { @@ -3423,7 +3455,6 @@ var ( http2VerboseLogs bool http2logFrameWrites bool http2logFrameReads bool - http2inTests bool // Enabling extended CONNECT by causes browsers to attempt to use // WebSockets-over-HTTP/2. This results in problems when the server's websocket @@ -4103,6 +4134,10 @@ type http2Server struct { type http2serverInternalState struct { mu sync.Mutex activeConns map[*http2serverConn]struct{} + + // Pool of error channels. This is per-Server rather than global + // because channels can't be reused across synctest bubbles. + errChanPool sync.Pool } func (s *http2serverInternalState) registerConn(sc *http2serverConn) { @@ -4134,6 +4169,27 @@ func (s *http2serverInternalState) startGracefulShutdown() { s.mu.Unlock() } +// Global error channel pool used for uninitialized Servers. +// We use a per-Server pool when possible to avoid using channels across synctest bubbles. +var http2errChanPool = sync.Pool{ + New: func() any { return make(chan error, 1) }, +} + +func (s *http2serverInternalState) getErrChan() chan error { + if s == nil { + return http2errChanPool.Get().(chan error) // Server used without calling ConfigureServer + } + return s.errChanPool.Get().(chan error) +} + +func (s *http2serverInternalState) putErrChan(ch chan error) { + if s == nil { + http2errChanPool.Put(ch) // Server used without calling ConfigureServer + return + } + s.errChanPool.Put(ch) +} + // ConfigureServer adds HTTP/2 support to a net/http Server. // // The configuration conf may be nil. @@ -4146,7 +4202,10 @@ func http2ConfigureServer(s *Server, conf *http2Server) error { if conf == nil { conf = new(http2Server) } - conf.state = &http2serverInternalState{activeConns: make(map[*http2serverConn]struct{})} + conf.state = &http2serverInternalState{ + activeConns: make(map[*http2serverConn]struct{}), + errChanPool: sync.Pool{New: func() any { return make(chan error, 1) }}, + } if h1, h2 := s, conf; h2.IdleTimeout == 0 { if h1.IdleTimeout != 0 { h2.IdleTimeout = h1.IdleTimeout @@ -5052,25 +5111,6 @@ func (sc *http2serverConn) readPreface() error { } } -var http2errChanPool = sync.Pool{ - New: func() interface{} { return make(chan error, 1) }, -} - -func http2getErrChan() chan error { - if http2inTests { - // Channels cannot be reused across synctest tests. - return make(chan error, 1) - } else { - return http2errChanPool.Get().(chan error) - } -} - -func http2putErrChan(ch chan error) { - if !http2inTests { - http2errChanPool.Put(ch) - } -} - var http2writeDataPool = sync.Pool{ New: func() interface{} { return new(http2writeData) }, } @@ -5078,7 +5118,7 @@ var http2writeDataPool = sync.Pool{ // writeDataFromHandler writes DATA response frames from a handler on // the given stream. func (sc *http2serverConn) writeDataFromHandler(stream *http2stream, data []byte, endStream bool) error { - ch := http2getErrChan() + ch := sc.srv.state.getErrChan() writeArg := http2writeDataPool.Get().(*http2writeData) *writeArg = http2writeData{stream.id, data, endStream} err := sc.writeFrameFromHandler(http2FrameWriteRequest{ @@ -5110,7 +5150,7 @@ func (sc *http2serverConn) writeDataFromHandler(stream *http2stream, data []byte return http2errStreamClosed } } - http2putErrChan(ch) + sc.srv.state.putErrChan(ch) if frameWriteDone { http2writeDataPool.Put(writeArg) } @@ -6364,7 +6404,7 @@ func (sc *http2serverConn) writeHeaders(st *http2stream, headerData *http2writeR // waiting for this frame to be written, so an http.Flush mid-handler // writes out the correct value of keys, before a handler later potentially // mutates it. - errc = http2getErrChan() + errc = sc.srv.state.getErrChan() } if err := sc.writeFrameFromHandler(http2FrameWriteRequest{ write: headerData, @@ -6376,7 +6416,7 @@ func (sc *http2serverConn) writeHeaders(st *http2stream, headerData *http2writeR if errc != nil { select { case err := <-errc: - http2putErrChan(errc) + sc.srv.state.putErrChan(errc) return err case <-sc.doneServing: return http2errClientDisconnected @@ -7057,7 +7097,7 @@ func (w *http2responseWriter) Push(target string, opts *PushOptions) error { method: opts.Method, url: u, header: http2cloneHeader(opts.Header), - done: http2getErrChan(), + done: sc.srv.state.getErrChan(), } select { @@ -7074,7 +7114,7 @@ func (w *http2responseWriter) Push(target string, opts *PushOptions) error { case <-st.cw: return http2errStreamClosed case err := <-msg.done: - http2putErrChan(msg.done) + sc.srv.state.putErrChan(msg.done) return err } } @@ -7577,6 +7617,7 @@ type http2ClientConn struct { readIdleTimeout time.Duration pingTimeout time.Duration extendedConnectAllowed bool + strictMaxConcurrentStreams bool // rstStreamPingsBlocked works around an unfortunate gRPC behavior. // gRPC strictly limits the number of PING frames that it will receive. @@ -8007,7 +8048,8 @@ func (t *http2Transport) newClientConn(c net.Conn, singleUse bool) (*http2Client initialWindowSize: 65535, // spec default initialStreamRecvWindowSize: conf.MaxUploadBufferPerStream, maxConcurrentStreams: http2initialMaxConcurrentStreams, // "infinite", per spec. Use a smaller value until we have received server settings. - peerMaxHeaderListSize: 0xffffffffffffffff, // "infinite", per spec. Use 2^64-1 instead. + strictMaxConcurrentStreams: conf.StrictMaxConcurrentRequests, + peerMaxHeaderListSize: 0xffffffffffffffff, // "infinite", per spec. Use 2^64-1 instead. streams: make(map[uint32]*http2clientStream), singleUse: singleUse, seenSettingsChan: make(chan struct{}), @@ -8241,7 +8283,7 @@ func (cc *http2ClientConn) idleStateLocked() (st http2clientConnIdleState) { return } var maxConcurrentOkay bool - if cc.t.StrictMaxConcurrentStreams { + if cc.strictMaxConcurrentStreams { // We'll tell the caller we can take a new request to // prevent the caller from dialing a new TCP // connection, but then we'll block later before @@ -10884,6 +10926,8 @@ type http2OpenStreamOptions struct { // PusherID is zero if the stream was initiated by the client. Otherwise, // PusherID names the stream that pushed the newly opened stream. PusherID uint32 + // priority is used to set the priority of the newly opened stream. + priority http2PriorityParam } // FrameWriteRequest is a request to write a frame. @@ -11095,7 +11139,7 @@ func (p *http2writeQueuePool) get() *http2writeQueue { } // RFC 7540, Section 5.3.5: the default weight is 16. -const http2priorityDefaultWeight = 15 // 16 = 15 + 1 +const http2priorityDefaultWeightRFC7540 = 15 // 16 = 15 + 1 // PriorityWriteSchedulerConfig configures a priorityWriteScheduler. type http2PriorityWriteSchedulerConfig struct { @@ -11150,8 +11194,8 @@ func http2NewPriorityWriteScheduler(cfg *http2PriorityWriteSchedulerConfig) http } } - ws := &http2priorityWriteScheduler{ - nodes: make(map[uint32]*http2priorityNode), + ws := &http2priorityWriteSchedulerRFC7540{ + nodes: make(map[uint32]*http2priorityNodeRFC7540), maxClosedNodesInTree: cfg.MaxClosedNodesInTree, maxIdleNodesInTree: cfg.MaxIdleNodesInTree, enableWriteThrottle: cfg.ThrottleOutOfOrderWrites, @@ -11165,32 +11209,32 @@ func http2NewPriorityWriteScheduler(cfg *http2PriorityWriteSchedulerConfig) http return ws } -type http2priorityNodeState int +type http2priorityNodeStateRFC7540 int const ( - http2priorityNodeOpen http2priorityNodeState = iota - http2priorityNodeClosed - http2priorityNodeIdle + http2priorityNodeOpenRFC7540 http2priorityNodeStateRFC7540 = iota + http2priorityNodeClosedRFC7540 + http2priorityNodeIdleRFC7540 ) -// priorityNode is a node in an HTTP/2 priority tree. +// priorityNodeRFC7540 is a node in an HTTP/2 priority tree. // Each node is associated with a single stream ID. // See RFC 7540, Section 5.3. -type http2priorityNode struct { - q http2writeQueue // queue of pending frames to write - id uint32 // id of the stream, or 0 for the root of the tree - weight uint8 // the actual weight is weight+1, so the value is in [1,256] - state http2priorityNodeState // open | closed | idle - bytes int64 // number of bytes written by this node, or 0 if closed - subtreeBytes int64 // sum(node.bytes) of all nodes in this subtree +type http2priorityNodeRFC7540 struct { + q http2writeQueue // queue of pending frames to write + id uint32 // id of the stream, or 0 for the root of the tree + weight uint8 // the actual weight is weight+1, so the value is in [1,256] + state http2priorityNodeStateRFC7540 // open | closed | idle + bytes int64 // number of bytes written by this node, or 0 if closed + subtreeBytes int64 // sum(node.bytes) of all nodes in this subtree // These links form the priority tree. - parent *http2priorityNode - kids *http2priorityNode // start of the kids list - prev, next *http2priorityNode // doubly-linked list of siblings + parent *http2priorityNodeRFC7540 + kids *http2priorityNodeRFC7540 // start of the kids list + prev, next *http2priorityNodeRFC7540 // doubly-linked list of siblings } -func (n *http2priorityNode) setParent(parent *http2priorityNode) { +func (n *http2priorityNodeRFC7540) setParent(parent *http2priorityNodeRFC7540) { if n == parent { panic("setParent to self") } @@ -11225,7 +11269,7 @@ func (n *http2priorityNode) setParent(parent *http2priorityNode) { } } -func (n *http2priorityNode) addBytes(b int64) { +func (n *http2priorityNodeRFC7540) addBytes(b int64) { n.bytes += b for ; n != nil; n = n.parent { n.subtreeBytes += b @@ -11238,7 +11282,7 @@ func (n *http2priorityNode) addBytes(b int64) { // // f(n, openParent) takes two arguments: the node to visit, n, and a bool that is true // if any ancestor p of n is still open (ignoring the root node). -func (n *http2priorityNode) walkReadyInOrder(openParent bool, tmp *[]*http2priorityNode, f func(*http2priorityNode, bool) bool) bool { +func (n *http2priorityNodeRFC7540) walkReadyInOrder(openParent bool, tmp *[]*http2priorityNodeRFC7540, f func(*http2priorityNodeRFC7540, bool) bool) bool { if !n.q.empty() && f(n, openParent) { return true } @@ -11249,7 +11293,7 @@ func (n *http2priorityNode) walkReadyInOrder(openParent bool, tmp *[]*http2prior // Don't consider the root "open" when updating openParent since // we can't send data frames on the root stream (only control frames). if n.id != 0 { - openParent = openParent || (n.state == http2priorityNodeOpen) + openParent = openParent || (n.state == http2priorityNodeOpenRFC7540) } // Common case: only one kid or all kids have the same weight. @@ -11279,7 +11323,7 @@ func (n *http2priorityNode) walkReadyInOrder(openParent bool, tmp *[]*http2prior *tmp = append(*tmp, n.kids) n.kids.setParent(nil) } - sort.Sort(http2sortPriorityNodeSiblings(*tmp)) + sort.Sort(http2sortPriorityNodeSiblingsRFC7540(*tmp)) for i := len(*tmp) - 1; i >= 0; i-- { (*tmp)[i].setParent(n) // setParent inserts at the head of n.kids } @@ -11291,13 +11335,13 @@ func (n *http2priorityNode) walkReadyInOrder(openParent bool, tmp *[]*http2prior return false } -type http2sortPriorityNodeSiblings []*http2priorityNode +type http2sortPriorityNodeSiblingsRFC7540 []*http2priorityNodeRFC7540 -func (z http2sortPriorityNodeSiblings) Len() int { return len(z) } +func (z http2sortPriorityNodeSiblingsRFC7540) Len() int { return len(z) } -func (z http2sortPriorityNodeSiblings) Swap(i, k int) { z[i], z[k] = z[k], z[i] } +func (z http2sortPriorityNodeSiblingsRFC7540) Swap(i, k int) { z[i], z[k] = z[k], z[i] } -func (z http2sortPriorityNodeSiblings) Less(i, k int) bool { +func (z http2sortPriorityNodeSiblingsRFC7540) Less(i, k int) bool { // Prefer the subtree that has sent fewer bytes relative to its weight. // See sections 5.3.2 and 5.3.4. wi, bi := float64(z[i].weight+1), float64(z[i].subtreeBytes) @@ -11311,13 +11355,13 @@ func (z http2sortPriorityNodeSiblings) Less(i, k int) bool { return bi/bk <= wi/wk } -type http2priorityWriteScheduler struct { +type http2priorityWriteSchedulerRFC7540 struct { // root is the root of the priority tree, where root.id = 0. // The root queues control frames that are not associated with any stream. - root http2priorityNode + root http2priorityNodeRFC7540 // nodes maps stream ids to priority tree nodes. - nodes map[uint32]*http2priorityNode + nodes map[uint32]*http2priorityNodeRFC7540 // maxID is the maximum stream id in nodes. maxID uint32 @@ -11325,7 +11369,7 @@ type http2priorityWriteScheduler struct { // lists of nodes that have been closed or are idle, but are kept in // the tree for improved prioritization. When the lengths exceed either // maxClosedNodesInTree or maxIdleNodesInTree, old nodes are discarded. - closedNodes, idleNodes []*http2priorityNode + closedNodes, idleNodes []*http2priorityNodeRFC7540 // From the config. maxClosedNodesInTree int @@ -11334,19 +11378,19 @@ type http2priorityWriteScheduler struct { enableWriteThrottle bool // tmp is scratch space for priorityNode.walkReadyInOrder to reduce allocations. - tmp []*http2priorityNode + tmp []*http2priorityNodeRFC7540 // pool of empty queues for reuse. queuePool http2writeQueuePool } -func (ws *http2priorityWriteScheduler) OpenStream(streamID uint32, options http2OpenStreamOptions) { +func (ws *http2priorityWriteSchedulerRFC7540) OpenStream(streamID uint32, options http2OpenStreamOptions) { // The stream may be currently idle but cannot be opened or closed. if curr := ws.nodes[streamID]; curr != nil { - if curr.state != http2priorityNodeIdle { + if curr.state != http2priorityNodeIdleRFC7540 { panic(fmt.Sprintf("stream %d already opened", streamID)) } - curr.state = http2priorityNodeOpen + curr.state = http2priorityNodeOpenRFC7540 return } @@ -11358,11 +11402,11 @@ func (ws *http2priorityWriteScheduler) OpenStream(streamID uint32, options http2 if parent == nil { parent = &ws.root } - n := &http2priorityNode{ + n := &http2priorityNodeRFC7540{ q: *ws.queuePool.get(), id: streamID, - weight: http2priorityDefaultWeight, - state: http2priorityNodeOpen, + weight: http2priorityDefaultWeightRFC7540, + state: http2priorityNodeOpenRFC7540, } n.setParent(parent) ws.nodes[streamID] = n @@ -11371,19 +11415,19 @@ func (ws *http2priorityWriteScheduler) OpenStream(streamID uint32, options http2 } } -func (ws *http2priorityWriteScheduler) CloseStream(streamID uint32) { +func (ws *http2priorityWriteSchedulerRFC7540) CloseStream(streamID uint32) { if streamID == 0 { panic("violation of WriteScheduler interface: cannot close stream 0") } if ws.nodes[streamID] == nil { panic(fmt.Sprintf("violation of WriteScheduler interface: unknown stream %d", streamID)) } - if ws.nodes[streamID].state != http2priorityNodeOpen { + if ws.nodes[streamID].state != http2priorityNodeOpenRFC7540 { panic(fmt.Sprintf("violation of WriteScheduler interface: stream %d already closed", streamID)) } n := ws.nodes[streamID] - n.state = http2priorityNodeClosed + n.state = http2priorityNodeClosedRFC7540 n.addBytes(-n.bytes) q := n.q @@ -11396,7 +11440,7 @@ func (ws *http2priorityWriteScheduler) CloseStream(streamID uint32) { } } -func (ws *http2priorityWriteScheduler) AdjustStream(streamID uint32, priority http2PriorityParam) { +func (ws *http2priorityWriteSchedulerRFC7540) AdjustStream(streamID uint32, priority http2PriorityParam) { if streamID == 0 { panic("adjustPriority on root") } @@ -11410,11 +11454,11 @@ func (ws *http2priorityWriteScheduler) AdjustStream(streamID uint32, priority ht return } ws.maxID = streamID - n = &http2priorityNode{ + n = &http2priorityNodeRFC7540{ q: *ws.queuePool.get(), id: streamID, - weight: http2priorityDefaultWeight, - state: http2priorityNodeIdle, + weight: http2priorityDefaultWeightRFC7540, + state: http2priorityNodeIdleRFC7540, } n.setParent(&ws.root) ws.nodes[streamID] = n @@ -11426,7 +11470,7 @@ func (ws *http2priorityWriteScheduler) AdjustStream(streamID uint32, priority ht parent := ws.nodes[priority.StreamDep] if parent == nil { n.setParent(&ws.root) - n.weight = http2priorityDefaultWeight + n.weight = http2priorityDefaultWeightRFC7540 return } @@ -11467,8 +11511,8 @@ func (ws *http2priorityWriteScheduler) AdjustStream(streamID uint32, priority ht n.weight = priority.Weight } -func (ws *http2priorityWriteScheduler) Push(wr http2FrameWriteRequest) { - var n *http2priorityNode +func (ws *http2priorityWriteSchedulerRFC7540) Push(wr http2FrameWriteRequest) { + var n *http2priorityNodeRFC7540 if wr.isControl() { n = &ws.root } else { @@ -11487,8 +11531,8 @@ func (ws *http2priorityWriteScheduler) Push(wr http2FrameWriteRequest) { n.q.push(wr) } -func (ws *http2priorityWriteScheduler) Pop() (wr http2FrameWriteRequest, ok bool) { - ws.root.walkReadyInOrder(false, &ws.tmp, func(n *http2priorityNode, openParent bool) bool { +func (ws *http2priorityWriteSchedulerRFC7540) Pop() (wr http2FrameWriteRequest, ok bool) { + ws.root.walkReadyInOrder(false, &ws.tmp, func(n *http2priorityNodeRFC7540, openParent bool) bool { limit := int32(math.MaxInt32) if openParent { limit = ws.writeThrottleLimit @@ -11514,7 +11558,7 @@ func (ws *http2priorityWriteScheduler) Pop() (wr http2FrameWriteRequest, ok bool return wr, ok } -func (ws *http2priorityWriteScheduler) addClosedOrIdleNode(list *[]*http2priorityNode, maxSize int, n *http2priorityNode) { +func (ws *http2priorityWriteSchedulerRFC7540) addClosedOrIdleNode(list *[]*http2priorityNodeRFC7540, maxSize int, n *http2priorityNodeRFC7540) { if maxSize == 0 { return } @@ -11528,7 +11572,7 @@ func (ws *http2priorityWriteScheduler) addClosedOrIdleNode(list *[]*http2priorit *list = append(*list, n) } -func (ws *http2priorityWriteScheduler) removeNode(n *http2priorityNode) { +func (ws *http2priorityWriteSchedulerRFC7540) removeNode(n *http2priorityNodeRFC7540) { for n.kids != nil { n.kids.setParent(n.parent) } @@ -11536,6 +11580,199 @@ func (ws *http2priorityWriteScheduler) removeNode(n *http2priorityNode) { delete(ws.nodes, n.id) } +type http2streamMetadata struct { + location *http2writeQueue + priority http2PriorityParam +} + +type http2priorityWriteSchedulerRFC9218 struct { + // control contains control frames (SETTINGS, PING, etc.). + control http2writeQueue + + // heads contain the head of a circular list of streams. + // We put these heads within a nested array that represents urgency and + // incremental, as defined in + // https://www.rfc-editor.org/rfc/rfc9218.html#name-priority-parameters. + // 8 represents u=0 up to u=7, and 2 represents i=false and i=true. + heads [8][2]*http2writeQueue + + // streams contains a mapping between each stream ID and their metadata, so + // we can quickly locate them when needing to, for example, adjust their + // priority. + streams map[uint32]http2streamMetadata + + // queuePool are empty queues for reuse. + queuePool http2writeQueuePool + + // prioritizeIncremental is used to determine whether we should prioritize + // incremental streams or not, when urgency is the same in a given Pop() + // call. + prioritizeIncremental bool +} + +func http2newPriorityWriteSchedulerRFC9128() http2WriteScheduler { + ws := &http2priorityWriteSchedulerRFC9218{ + streams: make(map[uint32]http2streamMetadata), + } + return ws +} + +func (ws *http2priorityWriteSchedulerRFC9218) OpenStream(streamID uint32, opt http2OpenStreamOptions) { + if ws.streams[streamID].location != nil { + panic(fmt.Errorf("stream %d already opened", streamID)) + } + q := ws.queuePool.get() + ws.streams[streamID] = http2streamMetadata{ + location: q, + priority: opt.priority, + } + + u, i := opt.priority.urgency, opt.priority.incremental + if ws.heads[u][i] == nil { + ws.heads[u][i] = q + q.next = q + q.prev = q + } else { + // Queues are stored in a ring. + // Insert the new stream before ws.head, putting it at the end of the list. + q.prev = ws.heads[u][i].prev + q.next = ws.heads[u][i] + q.prev.next = q + q.next.prev = q + } +} + +func (ws *http2priorityWriteSchedulerRFC9218) CloseStream(streamID uint32) { + metadata := ws.streams[streamID] + q, u, i := metadata.location, metadata.priority.urgency, metadata.priority.incremental + if q == nil { + return + } + if q.next == q { + // This was the only open stream. + ws.heads[u][i] = nil + } else { + q.prev.next = q.next + q.next.prev = q.prev + if ws.heads[u][i] == q { + ws.heads[u][i] = q.next + } + } + delete(ws.streams, streamID) + ws.queuePool.put(q) +} + +func (ws *http2priorityWriteSchedulerRFC9218) AdjustStream(streamID uint32, priority http2PriorityParam) { + metadata := ws.streams[streamID] + q, u, i := metadata.location, metadata.priority.urgency, metadata.priority.incremental + if q == nil { + return + } + + // Remove stream from current location. + if q.next == q { + // This was the only open stream. + ws.heads[u][i] = nil + } else { + q.prev.next = q.next + q.next.prev = q.prev + if ws.heads[u][i] == q { + ws.heads[u][i] = q.next + } + } + + // Insert stream to the new queue. + u, i = priority.urgency, priority.incremental + if ws.heads[u][i] == nil { + ws.heads[u][i] = q + q.next = q + q.prev = q + } else { + // Queues are stored in a ring. + // Insert the new stream before ws.head, putting it at the end of the list. + q.prev = ws.heads[u][i].prev + q.next = ws.heads[u][i] + q.prev.next = q + q.next.prev = q + } +} + +func (ws *http2priorityWriteSchedulerRFC9218) Push(wr http2FrameWriteRequest) { + if wr.isControl() { + ws.control.push(wr) + return + } + q := ws.streams[wr.StreamID()].location + if q == nil { + // This is a closed stream. + // wr should not be a HEADERS or DATA frame. + // We push the request onto the control queue. + if wr.DataSize() > 0 { + panic("add DATA on non-open stream") + } + ws.control.push(wr) + return + } + q.push(wr) +} + +func (ws *http2priorityWriteSchedulerRFC9218) Pop() (http2FrameWriteRequest, bool) { + // Control and RST_STREAM frames first. + if !ws.control.empty() { + return ws.control.shift(), true + } + + // On the next Pop(), we want to prioritize incremental if we prioritized + // non-incremental request of the same urgency this time. Vice-versa. + // i.e. when there are incremental and non-incremental requests at the same + // priority, we give 50% of our bandwidth to the incremental ones in + // aggregate and 50% to the first non-incremental one (since + // non-incremental streams do not use round-robin writes). + ws.prioritizeIncremental = !ws.prioritizeIncremental + + // Always prioritize lowest u (i.e. highest urgency level). + for u := range ws.heads { + for i := range ws.heads[u] { + // When we want to prioritize incremental, we try to pop i=true + // first before i=false when u is the same. + if ws.prioritizeIncremental { + i = (i + 1) % 2 + } + q := ws.heads[u][i] + if q == nil { + continue + } + for { + if wr, ok := q.consume(math.MaxInt32); ok { + if i == 1 { + // For incremental streams, we update head to q.next so + // we can round-robin between multiple streams that can + // immediately benefit from partial writes. + ws.heads[u][i] = q.next + } else { + // For non-incremental streams, we try to finish one to + // completion rather than doing round-robin. However, + // we update head here so that if q.consume() is !ok + // (e.g. the stream has no more frame to consume), head + // is updated to the next q that has frames to consume + // on future iterations. This way, we do not prioritize + // writing to unavailable stream on next Pop() calls, + // preventing head-of-line blocking. + ws.heads[u][i] = q + } + return wr, true + } + q = q.next + if q == ws.heads[u][i] { + break + } + } + + } + } + return http2FrameWriteRequest{}, false +} + // NewRandomWriteScheduler constructs a WriteScheduler that ignores HTTP/2 // priorities. Control frames like SETTINGS and PING are written before DATA // frames, but if no control frames are queued and multiple streams have queued @@ -11622,7 +11859,7 @@ type http2roundRobinWriteScheduler struct { } // newRoundRobinWriteScheduler constructs a new write scheduler. -// The round robin scheduler priorizes control frames +// The round robin scheduler prioritizes control frames // like SETTINGS and PING over DATA frames. // When there are no control frames to send, it performs a round-robin // selection from the ready streams. diff --git a/src/net/http/http2_test.go b/src/net/http/http2_test.go deleted file mode 100644 index 7841b05b593400..00000000000000 --- a/src/net/http/http2_test.go +++ /dev/null @@ -1,12 +0,0 @@ -// Copyright 2025 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -//go:build !nethttpomithttp2 - -package http - -func init() { - // Disable HTTP/2 internal channel pooling which interferes with synctest. - http2inTests = true -} diff --git a/src/net/http/internal/httpcommon/httpcommon.go b/src/net/http/internal/httpcommon/httpcommon.go index 5e0c24035aba20..e3f8ec79e094d3 100644 --- a/src/net/http/internal/httpcommon/httpcommon.go +++ b/src/net/http/internal/httpcommon/httpcommon.go @@ -202,7 +202,7 @@ type EncodeHeadersParam struct { DefaultUserAgent string } -// EncodeHeadersParam is the result of EncodeHeaders. +// EncodeHeadersResult is the result of EncodeHeaders. type EncodeHeadersResult struct { HasBody bool HasTrailers bool @@ -550,7 +550,7 @@ type ServerRequestResult struct { // If the request should be rejected, this is a short string suitable for passing // to the http2 package's CountError function. - // It might be a bit odd to return errors this way rather than returing an error, + // It might be a bit odd to return errors this way rather than returning an error, // but this ensures we don't forget to include a CountError reason. InvalidReason string } diff --git a/src/net/http/socks_bundle.go b/src/net/http/socks_bundle.go index 776b03d941a405..862e5fa2a5165d 100644 --- a/src/net/http/socks_bundle.go +++ b/src/net/http/socks_bundle.go @@ -453,7 +453,7 @@ func (up *socksUsernamePassword) Authenticate(ctx context.Context, rw io.ReadWri b = append(b, up.Username...) b = append(b, byte(len(up.Password))) b = append(b, up.Password...) - // TODO(mikio): handle IO deadlines and cancelation if + // TODO(mikio): handle IO deadlines and cancellation if // necessary if _, err := rw.Write(b); err != nil { return err diff --git a/src/vendor/golang.org/x/net/nettest/conntest.go b/src/vendor/golang.org/x/net/nettest/conntest.go index 4297d408c0477c..8b98dfe21c5d30 100644 --- a/src/vendor/golang.org/x/net/nettest/conntest.go +++ b/src/vendor/golang.org/x/net/nettest/conntest.go @@ -142,7 +142,7 @@ func testPingPong(t *testing.T, c1, c2 net.Conn) { } // testRacyRead tests that it is safe to mutate the input Read buffer -// immediately after cancelation has occurred. +// immediately after cancellation has occurred. func testRacyRead(t *testing.T, c1, c2 net.Conn) { go chunkedCopy(c2, rand.New(rand.NewSource(0))) @@ -170,7 +170,7 @@ func testRacyRead(t *testing.T, c1, c2 net.Conn) { } // testRacyWrite tests that it is safe to mutate the input Write buffer -// immediately after cancelation has occurred. +// immediately after cancellation has occurred. func testRacyWrite(t *testing.T, c1, c2 net.Conn) { go chunkedCopy(io.Discard, c2) @@ -318,7 +318,7 @@ func testCloseTimeout(t *testing.T, c1, c2 net.Conn) { defer wg.Wait() wg.Add(3) - // Test for cancelation upon connection closure. + // Test for cancellation upon connection closure. c1.SetDeadline(neverTimeout) go func() { defer wg.Done() diff --git a/src/vendor/modules.txt b/src/vendor/modules.txt index cf5c27c74579d0..a2a0c0b3e85f23 100644 --- a/src/vendor/modules.txt +++ b/src/vendor/modules.txt @@ -6,7 +6,7 @@ golang.org/x/crypto/cryptobyte golang.org/x/crypto/cryptobyte/asn1 golang.org/x/crypto/internal/alias golang.org/x/crypto/internal/poly1305 -# golang.org/x/net v0.44.0 +# golang.org/x/net v0.44.1-0.20251002015445-edb764c2296f ## explicit; go 1.24.0 golang.org/x/net/dns/dnsmessage golang.org/x/net/http/httpguts From 53845004d647e16b3de7c74e50cffaca77e028e9 Mon Sep 17 00:00:00 2001 From: Damien Neil Date: Thu, 2 Oct 2025 09:42:57 -0700 Subject: [PATCH 040/229] net/http/httputil: deprecate ReverseProxy.Director The Director function has been superseded by Rewrite. Rewrite avoids fundamental security issues with hop-by-hop header handling in the Director API and has better default handling of X-Forwarded-* headers. Fixes #73161 Change-Id: Iadaf3070e0082458f79fb892ade51cb7ce832802 Reviewed-on: https://go-review.googlesource.com/c/go/+/708615 Reviewed-by: Nicholas Husin LUCI-TryBot-Result: Go LUCI Reviewed-by: Nicholas Husin --- api/next/73161.txt | 1 + .../99-minor/net/http/httputil/73161.md | 11 ++ src/net/http/httputil/reverseproxy.go | 116 +++++++++++++----- 3 files changed, 98 insertions(+), 30 deletions(-) create mode 100644 api/next/73161.txt create mode 100644 doc/next/6-stdlib/99-minor/net/http/httputil/73161.md diff --git a/api/next/73161.txt b/api/next/73161.txt new file mode 100644 index 00000000000000..86526b597a9463 --- /dev/null +++ b/api/next/73161.txt @@ -0,0 +1 @@ +pkg net/http/httputil, type ReverseProxy struct, Director //deprecated #73161 diff --git a/doc/next/6-stdlib/99-minor/net/http/httputil/73161.md b/doc/next/6-stdlib/99-minor/net/http/httputil/73161.md new file mode 100644 index 00000000000000..f6318f85534746 --- /dev/null +++ b/doc/next/6-stdlib/99-minor/net/http/httputil/73161.md @@ -0,0 +1,11 @@ +The [ReverseProxy.Director] configuration field is deprecated +in favor of [ReverseProxy.Rewrite]. + +A malicious client can remove headers added by a `Director` function +by designating those headers as hop-by-hop. Since there is no way to address +this problem within the scope of the `Director` API, we added a new +`Rewrite` hook in Go 1.20. `Rewrite` hooks are provided with both the +unmodified inbound request received by the proxy and the outbound request +which will be sent by the proxy. + +Since the `Director` hook is fundamentally unsafe, we are now deprecating it. diff --git a/src/net/http/httputil/reverseproxy.go b/src/net/http/httputil/reverseproxy.go index 6ed4930727404b..9d8784cd2bc7a9 100644 --- a/src/net/http/httputil/reverseproxy.go +++ b/src/net/http/httputil/reverseproxy.go @@ -133,36 +133,6 @@ type ReverseProxy struct { // At most one of Rewrite or Director may be set. Rewrite func(*ProxyRequest) - // Director is a function which modifies - // the request into a new request to be sent - // using Transport. Its response is then copied - // back to the original client unmodified. - // Director must not access the provided Request - // after returning. - // - // By default, the X-Forwarded-For header is set to the - // value of the client IP address. If an X-Forwarded-For - // header already exists, the client IP is appended to the - // existing values. As a special case, if the header - // exists in the Request.Header map but has a nil value - // (such as when set by the Director func), the X-Forwarded-For - // header is not modified. - // - // To prevent IP spoofing, be sure to delete any pre-existing - // X-Forwarded-For header coming from the client or - // an untrusted proxy. - // - // Hop-by-hop headers are removed from the request after - // Director returns, which can remove headers added by - // Director. Use a Rewrite function instead to ensure - // modifications to the request are preserved. - // - // Unparsable query parameters are removed from the outbound - // request if Request.Form is set after Director returns. - // - // At most one of Rewrite or Director may be set. - Director func(*http.Request) - // The transport used to perform proxy requests. // If nil, http.DefaultTransport is used. Transport http.RoundTripper @@ -210,6 +180,88 @@ type ReverseProxy struct { // If nil, the default is to log the provided error and return // a 502 Status Bad Gateway response. ErrorHandler func(http.ResponseWriter, *http.Request, error) + + // Director is deprecated. Use Rewrite instead. + // + // This function is insecure: + // + // - Hop-by-hop headers are removed from the request after Director + // returns, which can remove headers added by Director. + // A client can designate headers as hop-by-hop by listing them + // in the Connection header, so this permits a malicious client + // to remove any headers that may be added by Director. + // + // - X-Forwarded-For, X-Forwarded-Host, and X-Forwarded-Proto + // headers in inbound requests are preserved by default, + // which can permit IP spoofing if the Director function is + // not careful to remove these headers. + // + // Rewrite addresses these issues. + // + // As an example of converting a Director function to Rewrite: + // + // // ReverseProxy with a Director function. + // proxy := &httputil.ReverseProxy{ + // Director: func(req *http.Request) { + // req.URL.Scheme = "https" + // req.URL.Host = proxyHost + // + // // A malicious client can remove this header. + // req.Header.Set("Some-Header", "some-header-value") + // + // // X-Forwarded-* headers sent by the client are preserved, + // // since Director did not remove them. + // }, + // } + // + // // ReverseProxy with a Rewrite function. + // proxy := &httputil.ReverseProxy{ + // Rewrite: func(preq *httputil.ProxyRequest) { + // // See also ProxyRequest.SetURL. + // preq.Out.URL.Scheme = "https" + // preq.Out.URL.Host = proxyHost + // + // // This header cannot be affected by a malicious client. + // preq.Out.Header.Set("Some-Header", "some-header-value") + // + // // X-Forwarded- headers sent by the client have been + // // removed from preq.Out. + // // ProxyRequest.SetXForwarded optionally adds new ones. + // preq.SetXForwarded() + // }, + // } + // + // Director is a function which modifies + // the request into a new request to be sent + // using Transport. Its response is then copied + // back to the original client unmodified. + // Director must not access the provided Request + // after returning. + // + // By default, the X-Forwarded-For header is set to the + // value of the client IP address. If an X-Forwarded-For + // header already exists, the client IP is appended to the + // existing values. As a special case, if the header + // exists in the Request.Header map but has a nil value + // (such as when set by the Director func), the X-Forwarded-For + // header is not modified. + // + // To prevent IP spoofing, be sure to delete any pre-existing + // X-Forwarded-For header coming from the client or + // an untrusted proxy. + // + // Hop-by-hop headers are removed from the request after + // Director returns, which can remove headers added by + // Director. Use a Rewrite function instead to ensure + // modifications to the request are preserved. + // + // Unparsable query parameters are removed from the outbound + // request if Request.Form is set after Director returns. + // + // At most one of Rewrite or Director may be set. + // + // Deprecated: Use Rewrite instead. + Director func(*http.Request) } // A BufferPool is an interface for getting and returning temporary @@ -259,6 +311,10 @@ func joinURLPath(a, b *url.URL) (path, rawpath string) { // // NewSingleHostReverseProxy does not rewrite the Host header. // +// For backwards compatibility reasons, NewSingleHostReverseProxy +// returns a ReverseProxy using the deprecated Director function. +// This proxy preserves X-Forwarded-* headers sent by the client. +// // To customize the ReverseProxy behavior beyond what // NewSingleHostReverseProxy provides, use ReverseProxy directly // with a Rewrite function. The ProxyRequest SetURL method From d5b950399de01a0e28eeb48d2c8474db4aad0e8a Mon Sep 17 00:00:00 2001 From: Tim Cooijmans Date: Tue, 30 Sep 2025 21:53:11 +0000 Subject: [PATCH 041/229] cmd/cgo: fix unaligned arguments typedmemmove crash on iOS Irregularly typedmemmove and bulkBarrierPreWrite crashes on unaligned arguments. By aligning the arguments this is fixed. Fixes #46893 Change-Id: I7beb9fdc31053fcb71bee6c6cb906dea31718c56 GitHub-Last-Rev: 46ae8b96889644aab60ea4284cf447a740354c6a GitHub-Pull-Request: golang/go#74868 Reviewed-on: https://go-review.googlesource.com/c/go/+/692935 Reviewed-by: Cherry Mui LUCI-TryBot-Result: Go LUCI Reviewed-by: Keith Randall Reviewed-by: Keith Randall --- src/cmd/cgo/internal/testout/out_test.go | 144 ++++++++++++++++++ .../cgo/internal/testout/testdata/aligned.go | 63 ++++++++ src/cmd/cgo/out.go | 13 +- 3 files changed, 219 insertions(+), 1 deletion(-) create mode 100644 src/cmd/cgo/internal/testout/out_test.go create mode 100644 src/cmd/cgo/internal/testout/testdata/aligned.go diff --git a/src/cmd/cgo/internal/testout/out_test.go b/src/cmd/cgo/internal/testout/out_test.go new file mode 100644 index 00000000000000..81dfa365871372 --- /dev/null +++ b/src/cmd/cgo/internal/testout/out_test.go @@ -0,0 +1,144 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package out_test + +import ( + "bufio" + "bytes" + "fmt" + "internal/testenv" + "internal/goarch" + "os" + "path/filepath" + "regexp" + "strconv" + "strings" + "testing" +) + +type methodAlign struct { + Method string + Align int +} + +var wantAligns = map[string]int{ + "ReturnEmpty": 1, + "ReturnOnlyUint8": 1, + "ReturnOnlyUint16": 2, + "ReturnOnlyUint32": 4, + "ReturnOnlyUint64": goarch.PtrSize, + "ReturnOnlyInt": goarch.PtrSize, + "ReturnOnlyPtr": goarch.PtrSize, + "ReturnByteSlice": goarch.PtrSize, + "ReturnString": goarch.PtrSize, + "InputAndReturnUint8": 1, + "MixedTypes": goarch.PtrSize, +} + +// TestAligned tests that the generated _cgo_export.c file has the wanted +// align attributes for struct types used as arguments or results of +// //exported functions. +func TestAligned(t *testing.T) { + testenv.MustHaveGoRun(t) + testenv.MustHaveCGO(t) + + testdata, err := filepath.Abs("testdata") + if err != nil { + t.Fatal(err) + } + + objDir := t.TempDir() + + cmd := testenv.Command(t, testenv.GoToolPath(t), "tool", "cgo", + "-objdir", objDir, + filepath.Join(testdata, "aligned.go")) + cmd.Stderr = new(bytes.Buffer) + + err = cmd.Run() + if err != nil { + t.Fatalf("%#q: %v\n%s", cmd, err, cmd.Stderr) + } + + haveAligns, err := parseAlign(filepath.Join(objDir, "_cgo_export.c")) + if err != nil { + t.Fatal(err) + } + + // Check that we have all the wanted methods + if len(haveAligns) != len(wantAligns) { + t.Fatalf("have %d methods with aligned, want %d", len(haveAligns), len(wantAligns)) + } + + for i := range haveAligns { + method := haveAligns[i].Method + haveAlign := haveAligns[i].Align + + wantAlign, ok := wantAligns[method] + if !ok { + t.Errorf("method %s: have aligned %d, want missing entry", method, haveAlign) + } else if haveAlign != wantAlign { + t.Errorf("method %s: have aligned %d, want %d", method, haveAlign, wantAlign) + } + } +} + +func parseAlign(filename string) ([]methodAlign, error) { + file, err := os.Open(filename) + if err != nil { + return nil, fmt.Errorf("failed to open file: %w", err) + } + defer file.Close() + + var results []methodAlign + scanner := bufio.NewScanner(file) + + // Regex to match function declarations like "struct MethodName_return MethodName(" + funcRegex := regexp.MustCompile(`^struct\s+(\w+)_return\s+(\w+)\(`) + // Regex to match simple function declarations like "GoSlice MethodName(" + simpleFuncRegex := regexp.MustCompile(`^Go\w+\s+(\w+)\(`) + // Regex to match void-returning exported functions like "void ReturnEmpty(" + voidFuncRegex := regexp.MustCompile(`^void\s+(\w+)\(`) + // Regex to match align attributes like "__attribute__((aligned(8)))" + alignRegex := regexp.MustCompile(`__attribute__\(\(aligned\((\d+)\)\)\)`) + + var currentMethod string + + for scanner.Scan() { + line := strings.TrimSpace(scanner.Text()) + + // Check if this line declares a function with struct return type + if matches := funcRegex.FindStringSubmatch(line); matches != nil { + currentMethod = matches[2] // Extract the method name + } else if matches := simpleFuncRegex.FindStringSubmatch(line); matches != nil { + // Check if this line declares a function with simple return type (like GoSlice) + currentMethod = matches[1] // Extract the method name + } else if matches := voidFuncRegex.FindStringSubmatch(line); matches != nil { + // Check if this line declares a void-returning function + currentMethod = matches[1] // Extract the method name + } + + // Check if this line contains align information + if alignMatches := alignRegex.FindStringSubmatch(line); alignMatches != nil && currentMethod != "" { + alignStr := alignMatches[1] + align, err := strconv.Atoi(alignStr) + if err != nil { + // Skip this entry if we can't parse the align as integer + currentMethod = "" + continue + } + results = append(results, methodAlign{ + Method: currentMethod, + Align: align, + }) + currentMethod = "" // Reset for next method + } + } + + if err := scanner.Err(); err != nil { + return nil, fmt.Errorf("error reading file: %w", err) + } + + return results, nil +} diff --git a/src/cmd/cgo/internal/testout/testdata/aligned.go b/src/cmd/cgo/internal/testout/testdata/aligned.go new file mode 100644 index 00000000000000..cea6f2889a0cad --- /dev/null +++ b/src/cmd/cgo/internal/testout/testdata/aligned.go @@ -0,0 +1,63 @@ +// Copyright 2025 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import "C" + +//export ReturnEmpty +func ReturnEmpty() { + return +} + +//export ReturnOnlyUint8 +func ReturnOnlyUint8() (uint8, uint8, uint8) { + return 1, 2, 3 +} + +//export ReturnOnlyUint16 +func ReturnOnlyUint16() (uint16, uint16, uint16) { + return 1, 2, 3 +} + +//export ReturnOnlyUint32 +func ReturnOnlyUint32() (uint32, uint32, uint32) { + return 1, 2, 3 +} + +//export ReturnOnlyUint64 +func ReturnOnlyUint64() (uint64, uint64, uint64) { + return 1, 2, 3 +} + +//export ReturnOnlyInt +func ReturnOnlyInt() (int, int, int) { + return 1, 2, 3 +} + +//export ReturnOnlyPtr +func ReturnOnlyPtr() (*int, *int, *int) { + a, b, c := 1, 2, 3 + return &a, &b, &c +} + +//export ReturnString +func ReturnString() string { + return "hello" +} + +//export ReturnByteSlice +func ReturnByteSlice() []byte { + return []byte{1, 2, 3} +} + +//export InputAndReturnUint8 +func InputAndReturnUint8(a, b, c uint8) (uint8, uint8, uint8) { + return a, b, c +} + +//export MixedTypes +func MixedTypes(a uint8, b uint16, c uint32, d uint64, e int, f *int) (uint8, uint16, uint32, uint64, int, *int) { + return a, b, c, d, e, f +} diff --git a/src/cmd/cgo/out.go b/src/cmd/cgo/out.go index 622d35ac7b3bab..a2bcdf89c5ad44 100644 --- a/src/cmd/cgo/out.go +++ b/src/cmd/cgo/out.go @@ -949,6 +949,8 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) { fmt.Fprintf(gotype, "struct {\n") off := int64(0) npad := 0 + // the align is at least 1 (for char) + maxAlign := int64(1) argField := func(typ ast.Expr, namePat string, args ...interface{}) { name := fmt.Sprintf(namePat, args...) t := p.cgoType(typ) @@ -963,6 +965,11 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) { noSourceConf.Fprint(gotype, fset, typ) fmt.Fprintf(gotype, "\n") off += t.Size + // keep track of the maximum alignment among all fields + // so that we can align the struct correctly + if t.Align > maxAlign { + maxAlign = t.Align + } } if fn.Recv != nil { argField(fn.Recv.List[0].Type, "recv") @@ -1047,7 +1054,11 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) { // string.h for memset, and is also robust to C++ // types with constructors. Both GCC and LLVM optimize // this into just zeroing _cgo_a. - fmt.Fprintf(fgcc, "\ttypedef %s %v _cgo_argtype;\n", ctype.String(), p.packedAttribute()) + // + // The struct should be aligned to the maximum alignment + // of any of its fields. This to avoid alignment + // issues. + fmt.Fprintf(fgcc, "\ttypedef %s %v __attribute__((aligned(%d))) _cgo_argtype;\n", ctype.String(), p.packedAttribute(), maxAlign) fmt.Fprintf(fgcc, "\tstatic _cgo_argtype _cgo_zero;\n") fmt.Fprintf(fgcc, "\t_cgo_argtype _cgo_a = _cgo_zero;\n") if gccResult != "void" && (len(fntype.Results.List) > 1 || len(fntype.Results.List[0].Names) > 1) { From adce7f196e6ac6d22e9bc851efea5f3ab650947c Mon Sep 17 00:00:00 2001 From: Cherry Mui Date: Thu, 2 Oct 2025 18:24:12 -0400 Subject: [PATCH 042/229] cmd/link: support .def file with MSVC clang toolchain lld-link supports .def file, but requires a "-def:" (or "/def:") flag. (MinGW linker, on the other hand, requires no flag.) Pass the flag when using MSVC-based toolchain. CL originally authored by Chressie Himpel. Change-Id: I8c327ab48d36b0bcbb1d127cff544ffdb06be38e Reviewed-on: https://go-review.googlesource.com/c/go/+/708716 LUCI-TryBot-Result: Go LUCI Reviewed-by: Chressie Himpel --- src/cmd/link/internal/ld/lib.go | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go index 79d3d37835e9ad..2c861129b52f9a 100644 --- a/src/cmd/link/internal/ld/lib.go +++ b/src/cmd/link/internal/ld/lib.go @@ -1787,9 +1787,13 @@ func (ctxt *Link) hostlink() { case ctxt.IsAIX(): fileName := xcoffCreateExportFile(ctxt) argv = append(argv, "-Wl,-bE:"+fileName) - case ctxt.IsWindows() && !slices.Contains(flagExtldflags, "-Wl,--export-all-symbols"): + case ctxt.IsWindows() && !slices.Contains(flagExtldflags, wlPrefix+"export-all-symbols"): fileName := peCreateExportFile(ctxt, filepath.Base(outopt)) - argv = append(argv, fileName) + prefix := "" + if isMSVC { + prefix = "-Wl,-def:" + } + argv = append(argv, prefix+fileName) } const unusedArguments = "-Qunused-arguments" From 630799c6c957994a7720b5d0b6bdd10f3acfc605 Mon Sep 17 00:00:00 2001 From: Daniel McCarney Date: Mon, 30 Jun 2025 12:45:36 -0400 Subject: [PATCH 043/229] crypto/tls: add flag to render HTML BoGo report Updates the BoGo test runner to add a `-bogo-html-report` flag. When provided, an HTML report is written to the flag argument path. The report shows the fail/pass/skip status of run tests and allows sorting/searching the output. Change-Id: I8c704a51fbb03500f4134ebfaba06248baa3ca2f Reviewed-on: https://go-review.googlesource.com/c/go/+/684955 Auto-Submit: Daniel McCarney Reviewed-by: Roland Shoemaker Reviewed-by: Carlos Amedee TryBot-Bypass: Daniel McCarney Commit-Queue: Carlos Amedee --- src/crypto/tls/bogo_shim_test.go | 152 ++++++++++++++++++++++++++++++- src/crypto/tls/handshake_test.go | 1 + 2 files changed, 152 insertions(+), 1 deletion(-) diff --git a/src/crypto/tls/bogo_shim_test.go b/src/crypto/tls/bogo_shim_test.go index 7cab568db80953..f3f19b34e9e4cc 100644 --- a/src/crypto/tls/bogo_shim_test.go +++ b/src/crypto/tls/bogo_shim_test.go @@ -13,6 +13,7 @@ import ( "encoding/pem" "flag" "fmt" + "html/template" "internal/byteorder" "internal/testenv" "io" @@ -25,10 +26,13 @@ import ( "strconv" "strings" "testing" + "time" "golang.org/x/crypto/cryptobyte" ) +const boringsslModVer = "v0.0.0-20250620172916-f51d8b099832" + var ( port = flag.String("port", "", "") server = flag.Bool("server", false, "") @@ -557,7 +561,6 @@ func TestBogoSuite(t *testing.T) { if *bogoLocalDir != "" { bogoDir = *bogoLocalDir } else { - const boringsslModVer = "v0.0.0-20250620172916-f51d8b099832" bogoDir = cryptotest.FetchModule(t, "boringssl.googlesource.com/boringssl.git", boringsslModVer) } @@ -606,6 +609,12 @@ func TestBogoSuite(t *testing.T) { t.Fatalf("failed to parse results JSON: %s", err) } + if *bogoReport != "" { + if err := generateReport(results, *bogoReport); err != nil { + t.Fatalf("failed to generate report: %v", err) + } + } + // assertResults contains test results we want to make sure // are present in the output. They are only checked if -bogo-filter // was not passed. @@ -655,6 +664,23 @@ func TestBogoSuite(t *testing.T) { } } +func generateReport(results bogoResults, outPath string) error { + data := reportData{ + Results: results, + Timestamp: time.Unix(int64(results.SecondsSinceEpoch), 0).Format("2006-01-02 15:04:05"), + Revision: boringsslModVer, + } + + tmpl := template.Must(template.New("report").Parse(reportTemplate)) + file, err := os.Create(outPath) + if err != nil { + return err + } + defer file.Close() + + return tmpl.Execute(file, data) +} + // bogoResults is a copy of boringssl.googlesource.com/boringssl/testresults.Results type bogoResults struct { Version int `json:"version"` @@ -669,3 +695,127 @@ type bogoResults struct { Error string `json:"error,omitempty"` } `json:"tests"` } + +type reportData struct { + Results bogoResults + SkipReasons map[string]string + Timestamp string + Revision string +} + +const reportTemplate = ` + + + + BoGo Results Report + + + +

BoGo Results Report

+ +
+ Generated: {{.Timestamp}} | BoGo Revision: {{.Revision}}
+ {{range $status, $count := .Results.NumFailuresByType}} + {{$status}}: {{$count}} | + {{end}} +
+ +
+ + +
+ + + + + + + + + + + + + {{range $name, $test := .Results.Tests}} + + + + + + + + {{end}} + +
Test NameStatusActualExpectedError
{{$name}}{{$test.Actual}}{{$test.Actual}}{{$test.Expected}}{{$test.Error}}
+ + + + +` diff --git a/src/crypto/tls/handshake_test.go b/src/crypto/tls/handshake_test.go index ea8ac6fc837ae7..13f1bb1dd50a19 100644 --- a/src/crypto/tls/handshake_test.go +++ b/src/crypto/tls/handshake_test.go @@ -47,6 +47,7 @@ var ( bogoMode = flag.Bool("bogo-mode", false, "Enabled bogo shim mode, ignore everything else") bogoFilter = flag.String("bogo-filter", "", "BoGo test filter") bogoLocalDir = flag.String("bogo-local-dir", "", "Local BoGo to use, instead of fetching from source") + bogoReport = flag.String("bogo-html-report", "", "File path to render an HTML report with BoGo results") ) func runTestAndUpdateIfNeeded(t *testing.T, name string, run func(t *testing.T, update bool), wait bool) { From a7917eed70c63840b2c59748c52ef9ff11fecf38 Mon Sep 17 00:00:00 2001 From: Michael Matloob Date: Mon, 17 Mar 2025 11:45:52 -0400 Subject: [PATCH 044/229] internal/buildcfg: enable specializedmalloc experiment Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64_c2s16-perf_vs_parent,gotip-linux-amd64_c3h88-perf_vs_parent,gotip-linux-arm64_c4ah72-perf_vs_parent,gotip-linux-arm64_c4as16-perf_vs_parent Change-Id: I6a6a6964c4c596bbf4f072b5a44a34c3ce4f6541 Reviewed-on: https://go-review.googlesource.com/c/go/+/696536 Reviewed-by: Michael Matloob LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Knyszek --- src/internal/buildcfg/exp.go | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/src/internal/buildcfg/exp.go b/src/internal/buildcfg/exp.go index 707776b374b0d4..d06913d9a7f25a 100644 --- a/src/internal/buildcfg/exp.go +++ b/src/internal/buildcfg/exp.go @@ -79,10 +79,11 @@ func ParseGOEXPERIMENT(goos, goarch, goexp string) (*ExperimentFlags, error) { dwarf5Supported := (goos != "darwin" && goos != "ios" && goos != "aix") baseline := goexperiment.Flags{ - RegabiWrappers: regabiSupported, - RegabiArgs: regabiSupported, - Dwarf5: dwarf5Supported, - RandomizedHeapBase64: true, + RegabiWrappers: regabiSupported, + RegabiArgs: regabiSupported, + Dwarf5: dwarf5Supported, + RandomizedHeapBase64: true, + SizeSpecializedMalloc: true, } // Start with the statically enabled set of experiments. From c54dc1418b6fbff4176aaaffcc9fab6f1ad631a6 Mon Sep 17 00:00:00 2001 From: matloob Date: Wed, 1 Oct 2025 12:06:14 -0400 Subject: [PATCH 045/229] runtime: support valgrind (but not asan) in specialized malloc functions We're adding this so that the compiler doesn't need to know about valgrind since it's just implemented using a build tag. Change-Id: I6a6a696452b0379caceca2ae4e49195016f7a90d Reviewed-on: https://go-review.googlesource.com/c/go/+/708296 Reviewed-by: Michael Matloob LUCI-TryBot-Result: Go LUCI Auto-Submit: Michael Matloob Reviewed-by: Michael Knyszek --- src/runtime/malloc_generated.go | 324 ++++++++++++++++++++++++++++++++ src/runtime/malloc_stubs.go | 9 + 2 files changed, 333 insertions(+) diff --git a/src/runtime/malloc_generated.go b/src/runtime/malloc_generated.go index 600048c67557b1..2215dbaddb2e1c 100644 --- a/src/runtime/malloc_generated.go +++ b/src/runtime/malloc_generated.go @@ -150,6 +150,10 @@ func mallocgcSmallScanNoHeaderSC1(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -304,6 +308,10 @@ func mallocgcSmallScanNoHeaderSC2(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -458,6 +466,10 @@ func mallocgcSmallScanNoHeaderSC3(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -612,6 +624,10 @@ func mallocgcSmallScanNoHeaderSC4(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -766,6 +782,10 @@ func mallocgcSmallScanNoHeaderSC5(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -920,6 +940,10 @@ func mallocgcSmallScanNoHeaderSC6(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -1074,6 +1098,10 @@ func mallocgcSmallScanNoHeaderSC7(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -1228,6 +1256,10 @@ func mallocgcSmallScanNoHeaderSC8(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -1382,6 +1414,10 @@ func mallocgcSmallScanNoHeaderSC9(size uintptr, typ *_type, needzero bool) unsaf gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -1536,6 +1572,10 @@ func mallocgcSmallScanNoHeaderSC10(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -1690,6 +1730,10 @@ func mallocgcSmallScanNoHeaderSC11(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -1844,6 +1888,10 @@ func mallocgcSmallScanNoHeaderSC12(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -1998,6 +2046,10 @@ func mallocgcSmallScanNoHeaderSC13(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -2152,6 +2204,10 @@ func mallocgcSmallScanNoHeaderSC14(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -2306,6 +2362,10 @@ func mallocgcSmallScanNoHeaderSC15(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -2460,6 +2520,10 @@ func mallocgcSmallScanNoHeaderSC16(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -2614,6 +2678,10 @@ func mallocgcSmallScanNoHeaderSC17(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -2768,6 +2836,10 @@ func mallocgcSmallScanNoHeaderSC18(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -2922,6 +2994,10 @@ func mallocgcSmallScanNoHeaderSC19(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -3076,6 +3152,10 @@ func mallocgcSmallScanNoHeaderSC20(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -3230,6 +3310,10 @@ func mallocgcSmallScanNoHeaderSC21(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -3384,6 +3468,10 @@ func mallocgcSmallScanNoHeaderSC22(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -3538,6 +3626,10 @@ func mallocgcSmallScanNoHeaderSC23(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -3692,6 +3784,10 @@ func mallocgcSmallScanNoHeaderSC24(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -3846,6 +3942,10 @@ func mallocgcSmallScanNoHeaderSC25(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4000,6 +4100,10 @@ func mallocgcSmallScanNoHeaderSC26(size uintptr, typ *_type, needzero bool) unsa gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4064,6 +4168,10 @@ func mallocTiny1(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4142,6 +4250,10 @@ func mallocTiny1(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4206,6 +4318,10 @@ func mallocTiny2(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4284,6 +4400,10 @@ func mallocTiny2(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4348,6 +4468,10 @@ func mallocTiny3(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4426,6 +4550,10 @@ func mallocTiny3(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4490,6 +4618,10 @@ func mallocTiny4(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4568,6 +4700,10 @@ func mallocTiny4(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4632,6 +4768,10 @@ func mallocTiny5(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4710,6 +4850,10 @@ func mallocTiny5(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4774,6 +4918,10 @@ func mallocTiny6(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4852,6 +5000,10 @@ func mallocTiny6(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4916,6 +5068,10 @@ func mallocTiny7(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -4994,6 +5150,10 @@ func mallocTiny7(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5058,6 +5218,10 @@ func mallocTiny8(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5136,6 +5300,10 @@ func mallocTiny8(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5200,6 +5368,10 @@ func mallocTiny9(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5278,6 +5450,10 @@ func mallocTiny9(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5342,6 +5518,10 @@ func mallocTiny10(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5420,6 +5600,10 @@ func mallocTiny10(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5484,6 +5668,10 @@ func mallocTiny11(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5562,6 +5750,10 @@ func mallocTiny11(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5626,6 +5818,10 @@ func mallocTiny12(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5704,6 +5900,10 @@ func mallocTiny12(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5768,6 +5968,10 @@ func mallocTiny13(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5846,6 +6050,10 @@ func mallocTiny13(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5910,6 +6118,10 @@ func mallocTiny14(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -5988,6 +6200,10 @@ func mallocTiny14(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6052,6 +6268,10 @@ func mallocTiny15(size uintptr, typ *_type, needzero bool) unsafe.Pointer { const elemsize = 0 { + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6130,6 +6350,10 @@ func mallocTiny15(size uintptr, typ *_type, needzero bool) unsafe.Pointer { x = add(x, elemsize-constsize) } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6223,6 +6447,10 @@ func mallocgcSmallNoScanSC2(size uintptr, typ *_type, needzero bool) unsafe.Poin gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6316,6 +6544,10 @@ func mallocgcSmallNoScanSC3(size uintptr, typ *_type, needzero bool) unsafe.Poin gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6409,6 +6641,10 @@ func mallocgcSmallNoScanSC4(size uintptr, typ *_type, needzero bool) unsafe.Poin gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6502,6 +6738,10 @@ func mallocgcSmallNoScanSC5(size uintptr, typ *_type, needzero bool) unsafe.Poin gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6595,6 +6835,10 @@ func mallocgcSmallNoScanSC6(size uintptr, typ *_type, needzero bool) unsafe.Poin gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6688,6 +6932,10 @@ func mallocgcSmallNoScanSC7(size uintptr, typ *_type, needzero bool) unsafe.Poin gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6781,6 +7029,10 @@ func mallocgcSmallNoScanSC8(size uintptr, typ *_type, needzero bool) unsafe.Poin gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6874,6 +7126,10 @@ func mallocgcSmallNoScanSC9(size uintptr, typ *_type, needzero bool) unsafe.Poin gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -6967,6 +7223,10 @@ func mallocgcSmallNoScanSC10(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7060,6 +7320,10 @@ func mallocgcSmallNoScanSC11(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7153,6 +7417,10 @@ func mallocgcSmallNoScanSC12(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7246,6 +7514,10 @@ func mallocgcSmallNoScanSC13(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7339,6 +7611,10 @@ func mallocgcSmallNoScanSC14(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7432,6 +7708,10 @@ func mallocgcSmallNoScanSC15(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7525,6 +7805,10 @@ func mallocgcSmallNoScanSC16(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7618,6 +7902,10 @@ func mallocgcSmallNoScanSC17(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7711,6 +7999,10 @@ func mallocgcSmallNoScanSC18(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7804,6 +8096,10 @@ func mallocgcSmallNoScanSC19(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7897,6 +8193,10 @@ func mallocgcSmallNoScanSC20(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -7990,6 +8290,10 @@ func mallocgcSmallNoScanSC21(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -8083,6 +8387,10 @@ func mallocgcSmallNoScanSC22(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -8176,6 +8484,10 @@ func mallocgcSmallNoScanSC23(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -8269,6 +8581,10 @@ func mallocgcSmallNoScanSC24(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -8362,6 +8678,10 @@ func mallocgcSmallNoScanSC25(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) @@ -8455,6 +8775,10 @@ func mallocgcSmallNoScanSC26(size uintptr, typ *_type, needzero bool) unsafe.Poi gcStart(t) } } + if valgrindenabled { + valgrindMalloc(x, size) + } + if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { assistG.gcAssistBytes -= int64(elemsize - size) diff --git a/src/runtime/malloc_stubs.go b/src/runtime/malloc_stubs.go index 7fd144418938fb..224746f3d41124 100644 --- a/src/runtime/malloc_stubs.go +++ b/src/runtime/malloc_stubs.go @@ -50,6 +50,8 @@ func mallocPanic(size uintptr, typ *_type, needzero bool) unsafe.Pointer { panic("not defined for sizeclass") } +// WARNING: mallocStub does not do any work for sanitizers so callers need +// to steer out of this codepath early if sanitizers are enabled. func mallocStub(size uintptr, typ *_type, needzero bool) unsafe.Pointer { if doubleCheckMalloc { if gcphase == _GCmarktermination { @@ -77,6 +79,13 @@ func mallocStub(size uintptr, typ *_type, needzero bool) unsafe.Pointer { // Actually do the allocation. x, elemsize := inlinedMalloc(size, typ, needzero) + // Notify valgrind, if enabled. + // To allow the compiler to not know about valgrind, we do valgrind instrumentation + // unlike the other sanitizers. + if valgrindenabled { + valgrindMalloc(x, size) + } + // Adjust our GC assist debt to account for internal fragmentation. if gcBlackenEnabled != 0 && elemsize != 0 { if assistG := getg().m.curg; assistG != nil { From ebb72bef44a0e125c7f900a04af6538e3c39dfc6 Mon Sep 17 00:00:00 2001 From: Cherry Mui Date: Fri, 20 Jun 2025 12:02:18 -0400 Subject: [PATCH 046/229] cmd/compile: don't treat devel compiler as a released compiler The compiler has a logic to print different messages on internal compiler error depending on whether this is a released version of Go. It hides the panic stack trace if it is a released version. It does this by checking the version and see if it has a "go" prefix. This includes all the released versions. However, for a non- released build, if there is no explicit version set, cmd/dist now sets the toolchain version as go1.X-devel_XXX, which makes it be treated as a released compiler, and causes the stack trace to be hidden. Change the logic to not match a devel compiler as a released compiler. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: I5d3b2101527212f825b6e4000b36030c4f83870b Reviewed-on: https://go-review.googlesource.com/c/go/+/682975 Reviewed-by: David Chase LUCI-TryBot-Result: Go LUCI Reviewed-on: https://go-review.googlesource.com/c/go/+/708855 Reviewed-by: Junyang Shao --- src/cmd/compile/internal/base/print.go | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/cmd/compile/internal/base/print.go b/src/cmd/compile/internal/base/print.go index 119f06fbc03351..9e3348c1ecca89 100644 --- a/src/cmd/compile/internal/base/print.go +++ b/src/cmd/compile/internal/base/print.go @@ -220,7 +220,7 @@ func FatalfAt(pos src.XPos, format string, args ...interface{}) { fmt.Printf("\n") // If this is a released compiler version, ask for a bug report. - if Debug.Panic == 0 && strings.HasPrefix(buildcfg.Version, "go") { + if Debug.Panic == 0 && strings.HasPrefix(buildcfg.Version, "go") && !strings.Contains(buildcfg.Version, "devel") { fmt.Printf("\n") fmt.Printf("Please file a bug report including a short program that triggers the error.\n") fmt.Printf("https://go.dev/issue/new\n") From ab043953cbd6e3cd262548710f35f05924aa8f32 Mon Sep 17 00:00:00 2001 From: David Chase Date: Wed, 2 Jul 2025 18:00:12 -0400 Subject: [PATCH 047/229] cmd/compile: minor tweak for race detector This makes the front-end a little bit less temp-happy when instrumenting, which repairs the "is it a constant?" test in the simd intrinsic conversion which is otherwise broken by race detection. Also, this will perhaps be better code. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: I84b7a45b7bff62bb2c9f9662466b50858d288645 Reviewed-on: https://go-review.googlesource.com/c/go/+/685637 LUCI-TryBot-Result: Go LUCI Reviewed-by: Junyang Shao Reviewed-by: Cherry Mui Reviewed-on: https://go-review.googlesource.com/c/go/+/708856 --- src/cmd/compile/internal/walk/walk.go | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/src/cmd/compile/internal/walk/walk.go b/src/cmd/compile/internal/walk/walk.go index a7d8182a747ce7..25add3d8043905 100644 --- a/src/cmd/compile/internal/walk/walk.go +++ b/src/cmd/compile/internal/walk/walk.go @@ -275,6 +275,15 @@ func backingArrayPtrLen(n ir.Node) (ptr, length ir.Node) { // function calls, which could clobber function call arguments/results // currently on the stack. func mayCall(n ir.Node) bool { + // This is intended to avoid putting constants + // into temporaries with the race detector (or other + // instrumentation) which interferes with simple + // "this is a constant" tests in ssagen. + // Also, it will generally lead to better code. + if n.Op() == ir.OLITERAL { + return false + } + // When instrumenting, any expression might require function calls. if base.Flag.Cfg.Instrumenting { return true From 10e796884905d23ab2419cc158769e8fdc73de4e Mon Sep 17 00:00:00 2001 From: Junyang Shao Date: Tue, 12 Aug 2025 16:53:44 +0000 Subject: [PATCH 048/229] cmd/compile: accounts rematerialize ops's output reginfo This CL implements the check for rematerializeable value's output regspec at its remateralization site. It has some potential problems, please see the TODO in regalloc.go. Fixes #70451. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: Ib624b967031776851136554719e939e9bf116b7c Reviewed-on: https://go-review.googlesource.com/c/go/+/695315 Reviewed-by: David Chase TryBot-Bypass: David Chase Reviewed-on: https://go-review.googlesource.com/c/go/+/708857 Reviewed-by: Junyang Shao LUCI-TryBot-Result: Go LUCI --- src/cmd/compile/internal/ssa/func.go | 1 + src/cmd/compile/internal/ssa/func_test.go | 5 ++++ src/cmd/compile/internal/ssa/regalloc.go | 23 +++++++++++++++++ src/cmd/compile/internal/ssa/regalloc_test.go | 25 +++++++++++++++++++ 4 files changed, 54 insertions(+) diff --git a/src/cmd/compile/internal/ssa/func.go b/src/cmd/compile/internal/ssa/func.go index 5736f0b8126484..fc8cb3f2fef0af 100644 --- a/src/cmd/compile/internal/ssa/func.go +++ b/src/cmd/compile/internal/ssa/func.go @@ -102,6 +102,7 @@ func (c *Config) NewFunc(fe Frontend, cache *Cache) *Func { NamedValues: make(map[LocalSlot][]*Value), CanonicalLocalSlots: make(map[LocalSlot]*LocalSlot), CanonicalLocalSplits: make(map[LocalSlotSplitKey]*LocalSlot), + OwnAux: &AuxCall{}, } } diff --git a/src/cmd/compile/internal/ssa/func_test.go b/src/cmd/compile/internal/ssa/func_test.go index a1e639e0486b62..4639d674e145fa 100644 --- a/src/cmd/compile/internal/ssa/func_test.go +++ b/src/cmd/compile/internal/ssa/func_test.go @@ -250,6 +250,11 @@ func Exit(arg string) ctrl { return ctrl{BlockExit, arg, []string{}} } +// Ret specifies a BlockRet. +func Ret(arg string) ctrl { + return ctrl{BlockRet, arg, []string{}} +} + // Eq specifies a BlockAMD64EQ. func Eq(cond, sub, alt string) ctrl { return ctrl{BlockAMD64EQ, cond, []string{sub, alt}} diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go index 1ce85a8f63b76a..56f9e550b2d439 100644 --- a/src/cmd/compile/internal/ssa/regalloc.go +++ b/src/cmd/compile/internal/ssa/regalloc.go @@ -609,6 +609,29 @@ func (s *regAllocState) allocValToReg(v *Value, mask regMask, nospill bool, pos } else if v.rematerializeable() { // Rematerialize instead of loading from the spill location. c = v.copyIntoWithXPos(s.curBlock, pos) + // We need to consider its output mask and potentially issue a Copy + // if there are register mask conflicts. + // This currently happens for the SIMD package only between GP and FP + // register. Because Intel's vector extension can put integer value into + // FP, which is seen as a vector. Example instruction: VPSLL[BWDQ] + // Because GP and FP masks do not overlap, mask & outputMask == 0 + // detects this situation thoroughly. + sourceMask := s.regspec(c).outputs[0].regs + if mask&sourceMask == 0 && !onWasmStack { + s.setOrig(c, v) + s.assignReg(s.allocReg(sourceMask, v), v, c) + // v.Type for the new OpCopy is likely wrong and it might delay the problem + // until ssa to asm lowering, which might need the types to generate the right + // assembly for OpCopy. For Intel's GP to FP move, it happens to be that + // MOV instruction has such a variant so it happens to be right. + // But it's unclear for other architectures or situations, and the problem + // might be exposed when the assembler sees illegal instructions. + // Right now make we still pick v.Type, because at least its size should be correct + // for the rematerialization case the amd64 SIMD package exposed. + // TODO: We might need to figure out a way to find the correct type or make + // the asm lowering use reg info only for OpCopy. + c = s.curBlock.NewValue1(pos, OpCopy, v.Type, c) + } } else { // Load v from its spill location. spill := s.makeSpill(v, s.curBlock) diff --git a/src/cmd/compile/internal/ssa/regalloc_test.go b/src/cmd/compile/internal/ssa/regalloc_test.go index 0f69b852d12971..79f94da0114f93 100644 --- a/src/cmd/compile/internal/ssa/regalloc_test.go +++ b/src/cmd/compile/internal/ssa/regalloc_test.go @@ -6,6 +6,7 @@ package ssa import ( "cmd/compile/internal/types" + "cmd/internal/obj/x86" "fmt" "testing" ) @@ -279,3 +280,27 @@ func numOps(b *Block, op Op) int { } return n } + +func TestRematerializeableRegCompatible(t *testing.T) { + c := testConfig(t) + f := c.Fun("entry", + Bloc("entry", + Valu("mem", OpInitMem, types.TypeMem, 0, nil), + Valu("x", OpAMD64MOVLconst, c.config.Types.Int32, 1, nil), + Valu("a", OpAMD64POR, c.config.Types.Float32, 0, nil, "x", "x"), + Valu("res", OpMakeResult, types.NewResults([]*types.Type{c.config.Types.Float32, types.TypeMem}), 0, nil, "a", "mem"), + Ret("res"), + ), + ) + regalloc(f.f) + checkFunc(f.f) + moveFound := false + for _, v := range f.f.Blocks[0].Values { + if v.Op == OpCopy && x86.REG_X0 <= v.Reg() && v.Reg() <= x86.REG_X31 { + moveFound = true + } + } + if !moveFound { + t.Errorf("Expects an Copy to be issued, but got: %+v", f.f) + } +} From ec70d1902355f10e0ab4788334b80db11ab69785 Mon Sep 17 00:00:00 2001 From: David Chase Date: Wed, 20 Aug 2025 12:29:02 -0400 Subject: [PATCH 049/229] cmd/compile: rewrite to elide Slicemask from len==c>0 slicing This might have been something that prove could be educated into figuring out, but this also works, and it also helps prove downstream. Adjusted the prove test, because this change moved a message. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: I5eabe639eff5db9cd9766a6a8666fdb4973829cb Reviewed-on: https://go-review.googlesource.com/c/go/+/697715 Commit-Queue: David Chase Reviewed-by: Cherry Mui TryBot-Bypass: David Chase Reviewed-on: https://go-review.googlesource.com/c/go/+/708858 LUCI-TryBot-Result: Go LUCI Reviewed-by: David Chase Reviewed-by: Junyang Shao --- .../compile/internal/ssa/_gen/generic.rules | 4 + .../compile/internal/ssa/rewritegeneric.go | 87 +++++++++++++++++++ test/prove.go | 4 +- 3 files changed, 93 insertions(+), 2 deletions(-) diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules index b16aa473cd5961..6fdea7cc7a3cdc 100644 --- a/src/cmd/compile/internal/ssa/_gen/generic.rules +++ b/src/cmd/compile/internal/ssa/_gen/generic.rules @@ -989,6 +989,10 @@ (Const64 [0]) (Const64 [0])) +// Special rule to help constant slicing; len > 0 implies cap > 0 implies Slicemask is all 1 +(SliceMake (AddPtr x (And64 y (Slicemask _))) w:(Const64 [c]) z) && c > 0 => (SliceMake (AddPtr x y) w z) +(SliceMake (AddPtr x (And32 y (Slicemask _))) w:(Const32 [c]) z) && c > 0 => (SliceMake (AddPtr x y) w z) + // interface ops (ConstInterface) => (IMake diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go index 5e0135be3a5be5..5720063f34b267 100644 --- a/src/cmd/compile/internal/ssa/rewritegeneric.go +++ b/src/cmd/compile/internal/ssa/rewritegeneric.go @@ -422,6 +422,8 @@ func rewriteValuegeneric(v *Value) bool { return rewriteValuegeneric_OpSliceCap(v) case OpSliceLen: return rewriteValuegeneric_OpSliceLen(v) + case OpSliceMake: + return rewriteValuegeneric_OpSliceMake(v) case OpSlicePtr: return rewriteValuegeneric_OpSlicePtr(v) case OpSlicemask: @@ -30514,6 +30516,91 @@ func rewriteValuegeneric_OpSliceLen(v *Value) bool { } return false } +func rewriteValuegeneric_OpSliceMake(v *Value) bool { + v_2 := v.Args[2] + v_1 := v.Args[1] + v_0 := v.Args[0] + b := v.Block + // match: (SliceMake (AddPtr x (And64 y (Slicemask _))) w:(Const64 [c]) z) + // cond: c > 0 + // result: (SliceMake (AddPtr x y) w z) + for { + if v_0.Op != OpAddPtr { + break + } + t := v_0.Type + _ = v_0.Args[1] + x := v_0.Args[0] + v_0_1 := v_0.Args[1] + if v_0_1.Op != OpAnd64 { + break + } + _ = v_0_1.Args[1] + v_0_1_0 := v_0_1.Args[0] + v_0_1_1 := v_0_1.Args[1] + for _i0 := 0; _i0 <= 1; _i0, v_0_1_0, v_0_1_1 = _i0+1, v_0_1_1, v_0_1_0 { + y := v_0_1_0 + if v_0_1_1.Op != OpSlicemask { + continue + } + w := v_1 + if w.Op != OpConst64 { + continue + } + c := auxIntToInt64(w.AuxInt) + z := v_2 + if !(c > 0) { + continue + } + v.reset(OpSliceMake) + v0 := b.NewValue0(v.Pos, OpAddPtr, t) + v0.AddArg2(x, y) + v.AddArg3(v0, w, z) + return true + } + break + } + // match: (SliceMake (AddPtr x (And32 y (Slicemask _))) w:(Const32 [c]) z) + // cond: c > 0 + // result: (SliceMake (AddPtr x y) w z) + for { + if v_0.Op != OpAddPtr { + break + } + t := v_0.Type + _ = v_0.Args[1] + x := v_0.Args[0] + v_0_1 := v_0.Args[1] + if v_0_1.Op != OpAnd32 { + break + } + _ = v_0_1.Args[1] + v_0_1_0 := v_0_1.Args[0] + v_0_1_1 := v_0_1.Args[1] + for _i0 := 0; _i0 <= 1; _i0, v_0_1_0, v_0_1_1 = _i0+1, v_0_1_1, v_0_1_0 { + y := v_0_1_0 + if v_0_1_1.Op != OpSlicemask { + continue + } + w := v_1 + if w.Op != OpConst32 { + continue + } + c := auxIntToInt32(w.AuxInt) + z := v_2 + if !(c > 0) { + continue + } + v.reset(OpSliceMake) + v0 := b.NewValue0(v.Pos, OpAddPtr, t) + v0.AddArg2(x, y) + v.AddArg3(v0, w, z) + return true + } + break + } + return false +} func rewriteValuegeneric_OpSlicePtr(v *Value) bool { v_0 := v.Args[0] // match: (SlicePtr (SliceMake (SlicePtr x) _ _)) diff --git a/test/prove.go b/test/prove.go index 70a27865cfd7c3..6d2bb0962be894 100644 --- a/test/prove.go +++ b/test/prove.go @@ -511,10 +511,10 @@ func f19() (e int64, err error) { func sm1(b []int, x int) { // Test constant argument to slicemask. - useSlice(b[2:8]) // ERROR "Proved slicemask not needed$" + useSlice(b[2:8]) // optimized away earlier by rewrite // Test non-constant argument with known limits. if cap(b) > 10 { - useSlice(b[2:]) + useSlice(b[2:]) // ERROR "Proved slicemask not needed$" } } From 1caa95acfa9d516eb3bc26292b5601bea25a4e79 Mon Sep 17 00:00:00 2001 From: David Chase Date: Wed, 3 Sep 2025 13:09:32 -0400 Subject: [PATCH 050/229] cmd/compile: enhance prove to deal with double-offset IsInBounds checks For chunked iterations (useful for, but not exclusive to, SIMD calculations) it is common to see the combination of ``` for ; i <= len(m)-4; i += 4 { ``` and ``` r0, r1, r2, r3 := m[i], m[i+1], m[i+2], m[i+3] `` Prove did not handle the case of len-offset1 vs index+offset2 checking, but this change fixes this. There may be other similar cases yet to handle -- this worked for the chunked loops for simd, as well as a handful in std. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: I3785df83028d517e5e5763206653b34b2befd3d0 Reviewed-on: https://go-review.googlesource.com/c/go/+/700696 Reviewed-by: Keith Randall Reviewed-by: Keith Randall LUCI-TryBot-Result: Go LUCI Reviewed-on: https://go-review.googlesource.com/c/go/+/708859 Reviewed-by: David Chase --- src/cmd/compile/internal/ssa/prove.go | 66 +++++++++++++++++++++++++++ test/prove.go | 12 ++--- 2 files changed, 72 insertions(+), 6 deletions(-) diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go index 309229b4d753b7..7b860a6f9ea2b0 100644 --- a/src/cmd/compile/internal/ssa/prove.go +++ b/src/cmd/compile/internal/ssa/prove.go @@ -2174,6 +2174,65 @@ func unsignedSubUnderflows(a, b uint64) bool { return a < b } +// checkForChunkedIndexBounds looks for index expressions of the form +// A[i+delta] where delta < K and i <= len(A)-K. That is, this is a chunked +// iteration where the index is not directly compared to the length. +func checkForChunkedIndexBounds(ft *factsTable, b *Block, index, bound *Value) bool { + if bound.Op != OpSliceLen { + return false + } + lim := ft.limits[index.ID] + if lim.min < 0 { + return false + } + i, delta := isConstDelta(index) + if i == nil { + return false + } + if delta < 0 { + return false + } + // special case for blocked iteration over a slice. + // slicelen > i + delta && <==== if clauses above + // && index >= 0 <==== if clause above + // delta >= 0 && <==== if clause above + // slicelen-K >/>= x <==== checked below + // && K >=/> delta <==== checked below + // then v > w + // example: i <=/< len - 4/3 means i+{0,1,2,3} are legal indices + for o := ft.orderings[i.ID]; o != nil; o = o.next { + if o.d != signed { + continue + } + if ow := o.w; ow.Op == OpAdd64 { + var lenOffset *Value + if ow.Args[0] == bound { + lenOffset = ow.Args[1] + } else if ow.Args[1] == bound { + lenOffset = ow.Args[0] + } + if lenOffset == nil || lenOffset.Op != OpConst64 { + continue + } + if K := -lenOffset.AuxInt; K >= 0 { + or := o.r + if or == lt { + or = lt | eq + K++ + if K < 0 { + continue + } + } + + if delta < K && or == lt|eq { + return true + } + } + } + } + return false +} + func addLocalFacts(ft *factsTable, b *Block) { // Propagate constant ranges among values in this block. // We do this before the second loop so that we have the @@ -2285,6 +2344,13 @@ func addLocalFacts(ft *factsTable, b *Block) { if v.Args[0].Op == OpSliceMake { ft.update(b, v, v.Args[0].Args[2], signed, eq) } + case OpIsInBounds: + if checkForChunkedIndexBounds(ft, b, v.Args[0], v.Args[1]) { + if b.Func.pass.debug > 0 { + b.Func.Warnl(v.Pos, "Proved %s for blocked indexing", v.Op) + } + ft.booleanTrue(v) + } case OpPhi: addLocalFactsPhi(ft, v) } diff --git a/test/prove.go b/test/prove.go index 6d2bb0962be894..bcc023dfec62fd 100644 --- a/test/prove.go +++ b/test/prove.go @@ -773,8 +773,8 @@ func indexGT0(b []byte, n int) { func unrollUpExcl(a []int) int { var i, x int for i = 0; i < len(a)-1; i += 2 { // ERROR "Induction variable: limits \[0,\?\), increment 2$" - x += a[i] // ERROR "Proved IsInBounds$" - x += a[i+1] + x += a[i] // ERROR "Proved IsInBounds$" + x += a[i+1] // ERROR "Proved IsInBounds( for blocked indexing)?$" } if i == len(a)-1 { x += a[i] @@ -786,8 +786,8 @@ func unrollUpExcl(a []int) int { func unrollUpIncl(a []int) int { var i, x int for i = 0; i <= len(a)-2; i += 2 { // ERROR "Induction variable: limits \[0,\?\], increment 2$" - x += a[i] // ERROR "Proved IsInBounds$" - x += a[i+1] + x += a[i] // ERROR "Proved IsInBounds$" + x += a[i+1] // ERROR "Proved IsInBounds( for blocked indexing)?$" } if i == len(a)-1 { x += a[i] @@ -839,7 +839,7 @@ func unrollExclStepTooLarge(a []int) int { var i, x int for i = 0; i < len(a)-1; i += 3 { x += a[i] - x += a[i+1] + x += a[i+1] // ERROR "Proved IsInBounds( for blocked indexing)?$" } if i == len(a)-1 { x += a[i] @@ -852,7 +852,7 @@ func unrollInclStepTooLarge(a []int) int { var i, x int for i = 0; i <= len(a)-2; i += 3 { x += a[i] - x += a[i+1] + x += a[i+1] // ERROR "Proved IsInBounds( for blocked indexing)?$" } if i == len(a)-1 { x += a[i] From 18cd4a1fc7d5387ae91ffc23328e4fc81f93681d Mon Sep 17 00:00:00 2001 From: Cherry Mui Date: Mon, 15 Sep 2025 21:27:19 -0400 Subject: [PATCH 051/229] cmd/compile: use the right type for spill slot Currently, when shuffling registers, if we need to spill a register, we always create a spill slot of type int64. The type doesn't actually matter, as long as it is wide enough to hold the registers. This is no longer true with SIMD registers, which could be wider than a int64. Create the slot with the proper type instead. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Test is SIMD specific so not included for now. Change-Id: I85c82e2532001bfdefe98c9446f2dd18583d49b4 Reviewed-on: https://go-review.googlesource.com/c/go/+/704055 TryBot-Bypass: Cherry Mui Reviewed-by: David Chase Reviewed-by: Junyang Shao Reviewed-on: https://go-review.googlesource.com/c/go/+/708860 LUCI-TryBot-Result: Go LUCI --- src/cmd/compile/internal/ssa/regalloc.go | 5 +---- src/cmd/compile/internal/ssa/value.go | 2 +- 2 files changed, 2 insertions(+), 5 deletions(-) diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go index 56f9e550b2d439..26c742d7fe78ff 100644 --- a/src/cmd/compile/internal/ssa/regalloc.go +++ b/src/cmd/compile/internal/ssa/regalloc.go @@ -2690,7 +2690,6 @@ func (e *edgeState) erase(loc Location) { // findRegFor finds a register we can use to make a temp copy of type typ. func (e *edgeState) findRegFor(typ *types.Type) Location { // Which registers are possibilities. - types := &e.s.f.Config.Types m := e.s.compatRegs(typ) // Pick a register. In priority order: @@ -2724,9 +2723,7 @@ func (e *edgeState) findRegFor(typ *types.Type) Location { if !c.rematerializeable() { x := e.p.NewValue1(c.Pos, OpStoreReg, c.Type, c) // Allocate a temp location to spill a register to. - // The type of the slot is immaterial - it will not be live across - // any safepoint. Just use a type big enough to hold any register. - t := LocalSlot{N: e.s.f.NewLocal(c.Pos, types.Int64), Type: types.Int64} + t := LocalSlot{N: e.s.f.NewLocal(c.Pos, c.Type), Type: c.Type} // TODO: reuse these slots. They'll need to be erased first. e.set(t, vid, x, false, c.Pos) if e.s.f.pass.debug > regDebug { diff --git a/src/cmd/compile/internal/ssa/value.go b/src/cmd/compile/internal/ssa/value.go index 55ab23ce9a0bcd..51a70c7fd4fdcd 100644 --- a/src/cmd/compile/internal/ssa/value.go +++ b/src/cmd/compile/internal/ssa/value.go @@ -600,7 +600,7 @@ func (v *Value) removeable() bool { func AutoVar(v *Value) (*ir.Name, int64) { if loc, ok := v.Block.Func.RegAlloc[v.ID].(LocalSlot); ok { if v.Type.Size() > loc.Type.Size() { - v.Fatalf("spill/restore type %s doesn't fit in slot type %s", v.Type, loc.Type) + v.Fatalf("v%d: spill/restore type %v doesn't fit in slot type %v", v.ID, v.Type, loc.Type) } return loc.N, loc.Off } From ad3db2562edf23cb4fb9a909ea11d57b65e304fb Mon Sep 17 00:00:00 2001 From: Junyang Shao Date: Tue, 16 Sep 2025 03:27:41 +0000 Subject: [PATCH 052/229] cmd/compile: handle rematerialized op for incompatible reg constraint This CL fixes an issue raised by contributor dominikh@. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Test is SIMD specific so not included for now. Change-Id: I941b330a6ba6f6c120c69951ddd24933f2f0b3ec Reviewed-on: https://go-review.googlesource.com/c/go/+/704056 LUCI-TryBot-Result: Go LUCI Reviewed-by: David Chase Reviewed-on: https://go-review.googlesource.com/c/go/+/708861 --- src/cmd/compile/internal/ssa/regalloc.go | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go index 26c742d7fe78ff..88861dfa14c840 100644 --- a/src/cmd/compile/internal/ssa/regalloc.go +++ b/src/cmd/compile/internal/ssa/regalloc.go @@ -2561,7 +2561,26 @@ func (e *edgeState) processDest(loc Location, vid ID, splice **Value, pos src.XP e.s.f.Fatalf("can't find source for %s->%s: %s\n", e.p, e.b, v.LongString()) } if dstReg { - x = v.copyInto(e.p) + // Handle incompatible registers. + // For #70451. + if e.s.regspec(v).outputs[0].regs®Mask(1< Date: Wed, 17 Sep 2025 14:25:16 -0400 Subject: [PATCH 053/229] cmd/compile: enhance the chunked indexing case to include reslicing this helps SIMD, but also helps plain old Go Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: Idcdacd54b6776f5c32b497bc94485052611cfa8d Reviewed-on: https://go-review.googlesource.com/c/go/+/704756 Reviewed-by: Keith Randall Reviewed-by: Keith Randall LUCI-TryBot-Result: Go LUCI Reviewed-on: https://go-review.googlesource.com/c/go/+/708862 Reviewed-by: David Chase --- src/cmd/compile/internal/ssa/prove.go | 34 ++++++++++++++++++++------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go index 7b860a6f9ea2b0..b1d49812c7d353 100644 --- a/src/cmd/compile/internal/ssa/prove.go +++ b/src/cmd/compile/internal/ssa/prove.go @@ -2177,10 +2177,18 @@ func unsignedSubUnderflows(a, b uint64) bool { // checkForChunkedIndexBounds looks for index expressions of the form // A[i+delta] where delta < K and i <= len(A)-K. That is, this is a chunked // iteration where the index is not directly compared to the length. -func checkForChunkedIndexBounds(ft *factsTable, b *Block, index, bound *Value) bool { - if bound.Op != OpSliceLen { +// if isReslice, then delta can be equal to K. +func checkForChunkedIndexBounds(ft *factsTable, b *Block, index, bound *Value, isReslice bool) bool { + if bound.Op != OpSliceLen && bound.Op != OpSliceCap { return false } + + // this is a slice bounds check against len or capacity, + // and refers back to a prior check against length, which + // will also work for the cap since that is not smaller + // than the length. + + slice := bound.Args[0] lim := ft.limits[index.ID] if lim.min < 0 { return false @@ -2206,9 +2214,9 @@ func checkForChunkedIndexBounds(ft *factsTable, b *Block, index, bound *Value) b } if ow := o.w; ow.Op == OpAdd64 { var lenOffset *Value - if ow.Args[0] == bound { + if bound := ow.Args[0]; bound.Op == OpSliceLen && bound.Args[0] == slice { lenOffset = ow.Args[1] - } else if ow.Args[1] == bound { + } else if bound := ow.Args[1]; bound.Op == OpSliceLen && bound.Args[0] == slice { lenOffset = ow.Args[0] } if lenOffset == nil || lenOffset.Op != OpConst64 { @@ -2216,12 +2224,15 @@ func checkForChunkedIndexBounds(ft *factsTable, b *Block, index, bound *Value) b } if K := -lenOffset.AuxInt; K >= 0 { or := o.r + if isReslice { + K++ + } if or == lt { or = lt | eq K++ - if K < 0 { - continue - } + } + if K < 0 { // We hate thinking about overflow + continue } if delta < K && or == lt|eq { @@ -2345,12 +2356,19 @@ func addLocalFacts(ft *factsTable, b *Block) { ft.update(b, v, v.Args[0].Args[2], signed, eq) } case OpIsInBounds: - if checkForChunkedIndexBounds(ft, b, v.Args[0], v.Args[1]) { + if checkForChunkedIndexBounds(ft, b, v.Args[0], v.Args[1], false) { if b.Func.pass.debug > 0 { b.Func.Warnl(v.Pos, "Proved %s for blocked indexing", v.Op) } ft.booleanTrue(v) } + case OpIsSliceInBounds: + if checkForChunkedIndexBounds(ft, b, v.Args[0], v.Args[1], true) { + if b.Func.pass.debug > 0 { + b.Func.Warnl(v.Pos, "Proved %s for blocked reslicing", v.Op) + } + ft.booleanTrue(v) + } case OpPhi: addLocalFactsPhi(ft, v) } From d91148c7a8b2d774ddea5c66c170d24937195df5 Mon Sep 17 00:00:00 2001 From: David Chase Date: Wed, 17 Sep 2025 17:19:15 -0400 Subject: [PATCH 054/229] cmd/compile: enhance prove to infer bounds in slice len/cap calculations the example comes up in chunked reslicing, e.g. A[i:] where i has a relationship with len(A)-K. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: Ib97dede6cfc7bbbd27b4f384988f741760686604 Reviewed-on: https://go-review.googlesource.com/c/go/+/704875 Reviewed-by: Keith Randall LUCI-TryBot-Result: Go LUCI Reviewed-by: Keith Randall Reviewed-on: https://go-review.googlesource.com/c/go/+/708863 Reviewed-by: David Chase --- src/cmd/compile/internal/ssa/prove.go | 65 ++++++++++++++++++++++++++- 1 file changed, 64 insertions(+), 1 deletion(-) diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go index b1d49812c7d353..5ed5be47443d77 100644 --- a/src/cmd/compile/internal/ssa/prove.go +++ b/src/cmd/compile/internal/ssa/prove.go @@ -1766,7 +1766,8 @@ func (ft *factsTable) flowLimit(v *Value) bool { b := ft.limits[v.Args[1].ID] sub := ft.newLimit(v, a.sub(b, uint(v.Type.Size())*8)) mod := ft.detectSignedMod(v) - return sub || mod + inferred := ft.detectSliceLenRelation(v) + return sub || mod || inferred case OpNeg64, OpNeg32, OpNeg16, OpNeg8: a := ft.limits[v.Args[0].ID] bitsize := uint(v.Type.Size()) * 8 @@ -1947,6 +1948,68 @@ func (ft *factsTable) detectSignedMod(v *Value) bool { // TODO: non-powers-of-2 return false } + +// detectSliceLenRelation matches the pattern where +// 1. v := slicelen - index, OR v := slicecap - index +// AND +// 2. index <= slicelen - K +// THEN +// +// slicecap - index >= slicelen - index >= K +// +// Note that "index" is not useed for indexing in this pattern, but +// in the motivating example (chunked slice iteration) it is. +func (ft *factsTable) detectSliceLenRelation(v *Value) (inferred bool) { + if v.Op != OpSub64 { + return false + } + + if !(v.Args[0].Op == OpSliceLen || v.Args[0].Op == OpSliceCap) { + return false + } + + slice := v.Args[0].Args[0] + index := v.Args[1] + + for o := ft.orderings[index.ID]; o != nil; o = o.next { + if o.d != signed { + continue + } + or := o.r + if or != lt && or != lt|eq { + continue + } + ow := o.w + if ow.Op != OpAdd64 && ow.Op != OpSub64 { + continue + } + var lenOffset *Value + if bound := ow.Args[0]; bound.Op == OpSliceLen && bound.Args[0] == slice { + lenOffset = ow.Args[1] + } else if bound := ow.Args[1]; bound.Op == OpSliceLen && bound.Args[0] == slice { + lenOffset = ow.Args[0] + } + if lenOffset == nil || lenOffset.Op != OpConst64 { + continue + } + K := lenOffset.AuxInt + if ow.Op == OpAdd64 { + K = -K + } + if K < 0 { + continue + } + if or == lt { + K++ + } + if K < 0 { // We hate thinking about overflow + continue + } + inferred = inferred || ft.signedMin(v, K) + } + return inferred +} + func (ft *factsTable) detectSignedModByPowerOfTwo(v *Value) bool { // We're looking for: // From 003b5ce1bc15cf265e74ba1ec4eb7cf801e49986 Mon Sep 17 00:00:00 2001 From: Junyang Shao Date: Fri, 19 Sep 2025 18:38:25 +0000 Subject: [PATCH 055/229] cmd/compile: fix SIMD const rematerialization condition This CL fixes a condition for the previous fix CL 704056. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Test is SIMD specific so not included for now. Change-Id: I1f1f8c6f72870403cb3dff14755c43385dc0c933 Reviewed-on: https://go-review.googlesource.com/c/go/+/705499 LUCI-TryBot-Result: Go LUCI Reviewed-by: Cherry Mui Reviewed-on: https://go-review.googlesource.com/c/go/+/708864 Reviewed-by: David Chase --- src/cmd/compile/internal/ssa/regalloc.go | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go index 88861dfa14c840..e959b8ed7df2eb 100644 --- a/src/cmd/compile/internal/ssa/regalloc.go +++ b/src/cmd/compile/internal/ssa/regalloc.go @@ -2561,22 +2561,25 @@ func (e *edgeState) processDest(loc Location, vid ID, splice **Value, pos src.XP e.s.f.Fatalf("can't find source for %s->%s: %s\n", e.p, e.b, v.LongString()) } if dstReg { - // Handle incompatible registers. + // We want to rematerialize v into a register that is incompatible with v's op's register mask. + // Instead of setting the wrong register for the rematerialized v, we should find the right register + // for it and emit an additional copy to move to the desired register. // For #70451. - if e.s.regspec(v).outputs[0].regs®Mask(1< Date: Mon, 22 Sep 2025 10:57:29 -0400 Subject: [PATCH 056/229] cmd/compile: remove stores to unread parameters Currently, we remove stores to local variables that are not read. We don't do that for arguments. But arguments and locals are essentially the same. Arguments are passed by value, and are not expected to be read in the caller's frame. So we can remove the writes to them as well. One exception is the cgo_unsafe_arg directive, which makes all the arguments effectively address-taken. cgo_unsafe_arg implies ABI0, so we just skip ABI0 functions' arguments. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: I8999fc50da6a87f22c1ec23e9a0c15483b6f7df8 Reviewed-on: https://go-review.googlesource.com/c/go/+/705815 LUCI-TryBot-Result: Go LUCI Reviewed-by: David Chase Reviewed-by: Junyang Shao Reviewed-on: https://go-review.googlesource.com/c/go/+/708865 --- src/cmd/compile/internal/ssa/deadstore.go | 22 +++++++++++++++---- src/runtime/testdata/testprog/badtraceback.go | 2 ++ test/codegen/stack.go | 6 +++++ 3 files changed, 26 insertions(+), 4 deletions(-) diff --git a/src/cmd/compile/internal/ssa/deadstore.go b/src/cmd/compile/internal/ssa/deadstore.go index 9e67e8339992c7..d0adff788c0a4f 100644 --- a/src/cmd/compile/internal/ssa/deadstore.go +++ b/src/cmd/compile/internal/ssa/deadstore.go @@ -7,6 +7,7 @@ package ssa import ( "cmd/compile/internal/ir" "cmd/compile/internal/types" + "cmd/internal/obj" ) // dse does dead-store elimination on the Function. @@ -213,7 +214,7 @@ func elimDeadAutosGeneric(f *Func) { case OpAddr, OpLocalAddr: // Propagate the address if it points to an auto. n, ok := v.Aux.(*ir.Name) - if !ok || n.Class != ir.PAUTO { + if !ok || (n.Class != ir.PAUTO && !isABIInternalParam(f, n)) { return } if addr[v] == nil { @@ -224,7 +225,7 @@ func elimDeadAutosGeneric(f *Func) { case OpVarDef: // v should be eliminated if we eliminate the auto. n, ok := v.Aux.(*ir.Name) - if !ok || n.Class != ir.PAUTO { + if !ok || (n.Class != ir.PAUTO && !isABIInternalParam(f, n)) { return } if elim[v] == nil { @@ -240,7 +241,7 @@ func elimDeadAutosGeneric(f *Func) { // may not be used by the inline code, but will be used by // panic processing). n, ok := v.Aux.(*ir.Name) - if !ok || n.Class != ir.PAUTO { + if !ok || (n.Class != ir.PAUTO && !isABIInternalParam(f, n)) { return } if !used.Has(n) { @@ -373,7 +374,7 @@ func elimUnreadAutos(f *Func) { if !ok { continue } - if n.Class != ir.PAUTO { + if n.Class != ir.PAUTO && !isABIInternalParam(f, n) { continue } @@ -413,3 +414,16 @@ func elimUnreadAutos(f *Func) { store.Op = OpCopy } } + +// isABIInternalParam returns whether n is a parameter of an ABIInternal +// function. For dead store elimination, we can treat parameters the same +// way as autos. Storing to a parameter can be removed if it is not read +// or address-taken. +// +// We check ABI here because for a cgo_unsafe_arg function (which is ABI0), +// all the args are effectively address-taken, but not necessarily have +// an Addr or LocalAddr op. We could probably just check for cgo_unsafe_arg, +// but ABIInternal is mostly what matters. +func isABIInternalParam(f *Func, n *ir.Name) bool { + return n.Class == ir.PPARAM && f.ABISelf.Which() == obj.ABIInternal +} diff --git a/src/runtime/testdata/testprog/badtraceback.go b/src/runtime/testdata/testprog/badtraceback.go index 09aa2b877ecf5a..455118a54371d7 100644 --- a/src/runtime/testdata/testprog/badtraceback.go +++ b/src/runtime/testdata/testprog/badtraceback.go @@ -44,6 +44,8 @@ func badLR2(arg int) { lrPtr := (*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&arg)) - lrOff)) *lrPtr = 0xbad + runtime.KeepAlive(lrPtr) // prevent dead store elimination + // Print a backtrace. This should include diagnostics for the // bad return PC and a hex dump. panic("backtrace") diff --git a/test/codegen/stack.go b/test/codegen/stack.go index 4e45d68f3816bd..59284ae88862a3 100644 --- a/test/codegen/stack.go +++ b/test/codegen/stack.go @@ -168,3 +168,9 @@ func getp1() *[4]int { func getp2() *[4]int { return nil } + +// Store to an argument without read can be removed. +func storeArg(a [2]int) { + // amd64:-`MOVQ\t\$123,.*\.a\+\d+\(SP\)` + a[1] = 123 +} From 1bca4c1673f5d90822086f34aed6de4a9bea2d93 Mon Sep 17 00:00:00 2001 From: David Chase Date: Wed, 17 Sep 2025 17:21:37 -0400 Subject: [PATCH 057/229] cmd/compile: improve slicemask removal this will be subsumed by pending changes in local slice representation, however this was easy and works well. Cherry-picked from the dev.simd branch. This CL is not necessarily SIMD specific. Apply early to reduce risk. Change-Id: I5b6eb10d257f04f906be7a8a6f2b6833992a39e8 Reviewed-on: https://go-review.googlesource.com/c/go/+/704876 Reviewed-by: Keith Randall LUCI-TryBot-Result: Go LUCI Reviewed-by: Keith Randall Reviewed-on: https://go-review.googlesource.com/c/go/+/708866 Reviewed-by: David Chase --- src/cmd/compile/internal/ssa/prove.go | 30 +++++-- test/loopbce.go | 118 +++++++++++++------------- 2 files changed, 81 insertions(+), 67 deletions(-) diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go index 5ed5be47443d77..b4f91fd4fd12dc 100644 --- a/src/cmd/compile/internal/ssa/prove.go +++ b/src/cmd/compile/internal/ssa/prove.go @@ -2529,24 +2529,38 @@ func simplifyBlock(sdom SparseTree, ft *factsTable, b *Block) { switch v.Op { case OpSlicemask: // Replace OpSlicemask operations in b with constants where possible. - x, delta := isConstDelta(v.Args[0]) - if x == nil { + cap := v.Args[0] + x, delta := isConstDelta(cap) + if x != nil { + // slicemask(x + y) + // if x is larger than -y (y is negative), then slicemask is -1. + lim := ft.limits[x.ID] + if lim.umin > uint64(-delta) { + if cap.Op == OpAdd64 { + v.reset(OpConst64) + } else { + v.reset(OpConst32) + } + if b.Func.pass.debug > 0 { + b.Func.Warnl(v.Pos, "Proved slicemask not needed") + } + v.AuxInt = -1 + } break } - // slicemask(x + y) - // if x is larger than -y (y is negative), then slicemask is -1. - lim := ft.limits[x.ID] - if lim.umin > uint64(-delta) { - if v.Args[0].Op == OpAdd64 { + lim := ft.limits[cap.ID] + if lim.umin > 0 { + if cap.Type.Size() == 8 { v.reset(OpConst64) } else { v.reset(OpConst32) } if b.Func.pass.debug > 0 { - b.Func.Warnl(v.Pos, "Proved slicemask not needed") + b.Func.Warnl(v.Pos, "Proved slicemask not needed (by limit)") } v.AuxInt = -1 } + case OpCtz8, OpCtz16, OpCtz32, OpCtz64: // On some architectures, notably amd64, we can generate much better // code for CtzNN if we know that the argument is non-zero. diff --git a/test/loopbce.go b/test/loopbce.go index 8bc44ece9455a0..8a58d942361221 100644 --- a/test/loopbce.go +++ b/test/loopbce.go @@ -9,7 +9,7 @@ import "math" func f0a(a []int) int { x := 0 for i := range a { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - x += a[i] // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += a[i] // ERROR "Proved IsInBounds$" } return x } @@ -17,7 +17,7 @@ func f0a(a []int) int { func f0b(a []int) int { x := 0 for i := range a { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - b := a[i:] // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + b := a[i:] // ERROR "Proved IsSliceInBounds$" x += b[0] } return x @@ -26,8 +26,8 @@ func f0b(a []int) int { func f0c(a []int) int { x := 0 for i := range a { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - b := a[:i+1] // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - x += b[0] // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + b := a[:i+1] // ERROR "Proved IsSliceInBounds$" + x += b[0] // ERROR "Proved IsInBounds$" } return x } @@ -43,7 +43,7 @@ func f1(a []int) int { func f2(a []int) int { x := 0 for i := 1; i < len(a); i++ { // ERROR "Induction variable: limits \[1,\?\), increment 1$" - x += a[i] // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += a[i] // ERROR "Proved IsInBounds$" } return x } @@ -51,7 +51,7 @@ func f2(a []int) int { func f4(a [10]int) int { x := 0 for i := 0; i < len(a); i += 2 { // ERROR "Induction variable: limits \[0,8\], increment 2$" - x += a[i] // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += a[i] // ERROR "Proved IsInBounds$" } return x } @@ -91,7 +91,7 @@ func f5_int8(a [10]int) int { //go:noinline func f6(a []int) { for i := range a { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - b := a[0:i] // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + b := a[0:i] // ERROR "Proved IsSliceInBounds$" f6(b) } } @@ -99,7 +99,7 @@ func f6(a []int) { func g0a(a string) int { x := 0 for i := 0; i < len(a); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += int(a[i]) // ERROR "Proved IsInBounds$" } return x } @@ -107,7 +107,7 @@ func g0a(a string) int { func g0b(a string) int { x := 0 for i := 0; len(a) > i; i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += int(a[i]) // ERROR "Proved IsInBounds$" } return x } @@ -115,7 +115,7 @@ func g0b(a string) int { func g0c(a string) int { x := 0 for i := len(a); i > 0; i-- { // ERROR "Induction variable: limits \(0,\?\], increment 1$" - x += int(a[i-1]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += int(a[i-1]) // ERROR "Proved IsInBounds$" } return x } @@ -123,7 +123,7 @@ func g0c(a string) int { func g0d(a string) int { x := 0 for i := len(a); 0 < i; i-- { // ERROR "Induction variable: limits \(0,\?\], increment 1$" - x += int(a[i-1]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += int(a[i-1]) // ERROR "Proved IsInBounds$" } return x } @@ -131,7 +131,7 @@ func g0d(a string) int { func g0e(a string) int { x := 0 for i := len(a) - 1; i >= 0; i-- { // ERROR "Induction variable: limits \[0,\?\], increment 1$" - x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += int(a[i]) // ERROR "Proved IsInBounds$" } return x } @@ -139,7 +139,7 @@ func g0e(a string) int { func g0f(a string) int { x := 0 for i := len(a) - 1; 0 <= i; i-- { // ERROR "Induction variable: limits \[0,\?\], increment 1$" - x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += int(a[i]) // ERROR "Proved IsInBounds$" } return x } @@ -148,7 +148,7 @@ func g1() int { a := "evenlength" x := 0 for i := 0; i < len(a); i += 2 { // ERROR "Induction variable: limits \[0,8\], increment 2$" - x += int(a[i]) // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + x += int(a[i]) // ERROR "Proved IsInBounds$" } return x } @@ -158,7 +158,7 @@ func g2() int { x := 0 for i := 0; i < len(a); i += 2 { // ERROR "Induction variable: limits \[0,8\], increment 2$" j := i - if a[i] == 'e' { // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + if a[i] == 'e' { // ERROR "Proved IsInBounds$" j = j + 1 } x += int(a[j]) @@ -169,29 +169,29 @@ func g2() int { func g3a() { a := "this string has length 25" for i := 0; i < len(a); i += 5 { // ERROR "Induction variable: limits \[0,20\], increment 5$" - useString(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useString(a[:i+3]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useString(a[:i+5]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + useString(a[i:]) // ERROR "Proved IsSliceInBounds$" "Proved slicemask not needed \(by limit\)$" + useString(a[:i+3]) // ERROR "Proved IsSliceInBounds$" + useString(a[:i+5]) // ERROR "Proved IsSliceInBounds$" useString(a[:i+6]) } } func g3b(a string) { for i := 0; i < len(a); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - useString(a[i+1:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + useString(a[i+1:]) // ERROR "Proved IsSliceInBounds$" } } func g3c(a string) { for i := 0; i < len(a); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - useString(a[:i+1]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + useString(a[:i+1]) // ERROR "Proved IsSliceInBounds$" } } func h1(a []byte) { c := a[:128] for i := range c { // ERROR "Induction variable: limits \[0,128\), increment 1$" - c[i] = byte(i) // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + c[i] = byte(i) // ERROR "Proved IsInBounds$" } } @@ -208,11 +208,11 @@ func k0(a [100]int) [100]int { continue } a[i-11] = i - a[i-10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" - a[i-5] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" - a[i] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" - a[i+5] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" - a[i+10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + a[i-10] = i // ERROR "Proved IsInBounds$" + a[i-5] = i // ERROR "Proved IsInBounds$" + a[i] = i // ERROR "Proved IsInBounds$" + a[i+5] = i // ERROR "Proved IsInBounds$" + a[i+10] = i // ERROR "Proved IsInBounds$" a[i+11] = i } return a @@ -225,12 +225,12 @@ func k1(a [100]int) [100]int { continue } useSlice(a[:i-11]) - useSlice(a[:i-10]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[:i-5]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[:i]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[:i+5]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[:i+10]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[:i+11]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + useSlice(a[:i-10]) // ERROR "Proved IsSliceInBounds$" + useSlice(a[:i-5]) // ERROR "Proved IsSliceInBounds$" + useSlice(a[:i]) // ERROR "Proved IsSliceInBounds$" + useSlice(a[:i+5]) // ERROR "Proved IsSliceInBounds$" + useSlice(a[:i+10]) // ERROR "Proved IsSliceInBounds$" + useSlice(a[:i+11]) // ERROR "Proved IsSliceInBounds$" useSlice(a[:i+12]) } @@ -243,13 +243,13 @@ func k2(a [100]int) [100]int { // This is a trick to prohibit sccp to optimize out the following out of bound check continue } - useSlice(a[i-11:]) - useSlice(a[i-10:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[i-5:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[i+5:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[i+10:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" - useSlice(a[i+11:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + useSlice(a[i-11:]) // ERROR "Proved slicemask not needed \(by limit\)$" + useSlice(a[i-10:]) // ERROR "Proved IsSliceInBounds$" "Proved slicemask not needed \(by limit\)$" + useSlice(a[i-5:]) // ERROR "Proved IsSliceInBounds$" "Proved slicemask not needed \(by limit\)$" + useSlice(a[i:]) // ERROR "Proved IsSliceInBounds$" "Proved slicemask not needed \(by limit\)$" + useSlice(a[i+5:]) // ERROR "Proved IsSliceInBounds$" "Proved slicemask not needed \(by limit\)$" + useSlice(a[i+10:]) // ERROR "Proved IsSliceInBounds$" "Proved slicemask not needed \(by limit\)$" + useSlice(a[i+11:]) // ERROR "Proved IsSliceInBounds$" useSlice(a[i+12:]) } return a @@ -262,7 +262,7 @@ func k3(a [100]int) [100]int { continue } a[i+9] = i - a[i+10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + a[i+10] = i // ERROR "Proved IsInBounds$" a[i+11] = i } return a @@ -275,7 +275,7 @@ func k3neg(a [100]int) [100]int { continue } a[i+9] = i - a[i+10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + a[i+10] = i // ERROR "Proved IsInBounds$" a[i+11] = i } return a @@ -288,7 +288,7 @@ func k3neg2(a [100]int) [100]int { continue } a[i+9] = i - a[i+10] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + a[i+10] = i // ERROR "Proved IsInBounds$" a[i+11] = i } return a @@ -299,7 +299,7 @@ func k4(a [100]int) [100]int { // and it isn't worth adding that special case to prove. min := (-1)<<63 + 1 for i := min; i < min+50; i++ { // ERROR "Induction variable: limits \[-9223372036854775807,-9223372036854775757\), increment 1$" - a[i-min] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + a[i-min] = i // ERROR "Proved IsInBounds$" } return a } @@ -307,8 +307,8 @@ func k4(a [100]int) [100]int { func k5(a [100]int) [100]int { max := (1 << 63) - 1 for i := max - 50; i < max; i++ { // ERROR "Induction variable: limits \[9223372036854775757,9223372036854775807\), increment 1$" - a[i-max+50] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" - a[i-(max-70)] = i // ERROR "(\([0-9]+\) )?Proved IsInBounds$" + a[i-max+50] = i // ERROR "Proved IsInBounds$" + a[i-(max-70)] = i // ERROR "Proved IsInBounds$" } return a } @@ -374,22 +374,22 @@ func d4() { } func d5() { - for i := int64(math.MinInt64 + 9); i > math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775803,-9223372036854775799\], increment 4" + for i := int64(math.MinInt64 + 9); i > math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775803,-9223372036854775799\], increment 4$" useString("foo") } - for i := int64(math.MinInt64 + 8); i > math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775804,-9223372036854775800\], increment 4" + for i := int64(math.MinInt64 + 8); i > math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775804,-9223372036854775800\], increment 4$" useString("foo") } for i := int64(math.MinInt64 + 7); i > math.MinInt64+2; i -= 4 { useString("foo") } - for i := int64(math.MinInt64 + 6); i > math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775802,-9223372036854775802\], increment 4" + for i := int64(math.MinInt64 + 6); i > math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775802,-9223372036854775802\], increment 4$" useString("foo") } - for i := int64(math.MinInt64 + 9); i >= math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775803,-9223372036854775799\], increment 4" + for i := int64(math.MinInt64 + 9); i >= math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775803,-9223372036854775799\], increment 4$" useString("foo") } - for i := int64(math.MinInt64 + 8); i >= math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775804,-9223372036854775800\], increment 4" + for i := int64(math.MinInt64 + 8); i >= math.MinInt64+2; i -= 4 { // ERROR "Induction variable: limits \[-9223372036854775804,-9223372036854775800\], increment 4$" useString("foo") } for i := int64(math.MinInt64 + 7); i >= math.MinInt64+2; i -= 4 { @@ -410,23 +410,23 @@ func bce1() { panic("invalid test: modulos should differ") } - for i := b; i < a; i += z { // ERROR "Induction variable: limits \[-1547,9223372036854772720\], increment 1337" + for i := b; i < a; i += z { // ERROR "Induction variable: limits \[-1547,9223372036854772720\], increment 1337$" useString("foobar") } } func nobce2(a string) { for i := int64(0); i < int64(len(a)); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - useString(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + useString(a[i:]) // ERROR "Proved IsSliceInBounds$" } for i := int64(0); i < int64(len(a))-31337; i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" - useString(a[i:]) // ERROR "(\([0-9]+\) )?Proved IsSliceInBounds$" + useString(a[i:]) // ERROR "Proved IsSliceInBounds$" } - for i := int64(0); i < int64(len(a))+int64(-1<<63); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" "Disproved Less64" + for i := int64(0); i < int64(len(a))+int64(-1<<63); i++ { // ERROR "Disproved Less64$" "Induction variable: limits \[0,\?\), increment 1$" useString(a[i:]) } j := int64(len(a)) - 123 - for i := int64(0); i < j+123+int64(-1<<63); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" "Disproved Less64" + for i := int64(0); i < j+123+int64(-1<<63); i++ { // ERROR "Disproved Less64$" "Induction variable: limits \[0,\?\), increment 1$" useString(a[i:]) } for i := int64(0); i < j+122+int64(-1<<63); i++ { // ERROR "Induction variable: limits \[0,\?\), increment 1$" @@ -455,16 +455,16 @@ func issue26116a(a []int) { func stride1(x *[7]int) int { s := 0 - for i := 0; i <= 8; i += 3 { // ERROR "Induction variable: limits \[0,6\], increment 3" - s += x[i] // ERROR "Proved IsInBounds" + for i := 0; i <= 8; i += 3 { // ERROR "Induction variable: limits \[0,6\], increment 3$" + s += x[i] // ERROR "Proved IsInBounds$" } return s } func stride2(x *[7]int) int { s := 0 - for i := 0; i < 9; i += 3 { // ERROR "Induction variable: limits \[0,6\], increment 3" - s += x[i] // ERROR "Proved IsInBounds" + for i := 0; i < 9; i += 3 { // ERROR "Induction variable: limits \[0,6\], increment 3$" + s += x[i] // ERROR "Proved IsInBounds$" } return s } From ee5369b003b17b34aa6417cf8c9b702f1cd76da1 Mon Sep 17 00:00:00 2001 From: qmuntal Date: Fri, 3 Oct 2025 11:18:47 +0200 Subject: [PATCH 058/229] cmd/link: add LIBRARY statement only with -buildmode=cshared When creating a .def file for Windows linking, add a LIBRARY statement only when building a DLL with -buildmode=cshared. That statement is documented to instruct the linker to create a DLL, overriding any other flag that might indicate building an executable. Fixes #75734 Change-Id: I0231435df70b71a493a39deb639f6328a8e354f6 Reviewed-on: https://go-review.googlesource.com/c/go/+/708815 Reviewed-by: Carlos Amedee Reviewed-by: Dominic Della Valle Reviewed-by: Cherry Mui LUCI-TryBot-Result: Go LUCI --- src/cmd/link/internal/ld/pe.go | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/cmd/link/internal/ld/pe.go b/src/cmd/link/internal/ld/pe.go index 0f0650e5e149e3..e0186f46b035d9 100644 --- a/src/cmd/link/internal/ld/pe.go +++ b/src/cmd/link/internal/ld/pe.go @@ -1758,7 +1758,9 @@ func peCreateExportFile(ctxt *Link, libName string) (fname string) { fname = filepath.Join(*flagTmpdir, "export_file.def") var buf bytes.Buffer - fmt.Fprintf(&buf, "LIBRARY %s\n", libName) + if ctxt.BuildMode == BuildModeCShared { + fmt.Fprintf(&buf, "LIBRARY %s\n", libName) + } buf.WriteString("EXPORTS\n") ldr := ctxt.loader From 2a71af11fc7e45903be9ab84e59c668bb051f528 Mon Sep 17 00:00:00 2001 From: Mateusz Poliwczak Date: Wed, 24 Sep 2025 16:40:55 +0200 Subject: [PATCH 059/229] net/url: improve URL docs The Raw fields are confusing and easy to use by mistake. Adds more context in comments to these fields. Also the current docs (and the names of these fields) of these boolean fields are not obvious that parser might produce them, so clarify that Change-Id: I6a6a69644834c3ccbf657147f771930b6875f721 Reviewed-on: https://go-review.googlesource.com/c/go/+/706515 Reviewed-by: Florian Lehner Reviewed-by: Sean Liao Reviewed-by: Damien Neil Reviewed-by: Carlos Amedee Auto-Submit: Damien Neil LUCI-TryBot-Result: Go LUCI --- src/net/url/url.go | 50 ++++++++++++++++++++++++++++++---------------- 1 file changed, 33 insertions(+), 17 deletions(-) diff --git a/src/net/url/url.go b/src/net/url/url.go index 2a57659460373d..015c5b2751974a 100644 --- a/src/net/url/url.go +++ b/src/net/url/url.go @@ -364,25 +364,41 @@ func escape(s string, mode encoding) string { // A consequence is that it is impossible to tell which slashes in the Path were // slashes in the raw URL and which were %2f. This distinction is rarely important, // but when it is, the code should use the [URL.EscapedPath] method, which preserves -// the original encoding of Path. +// the original encoding of Path. The Fragment field is also stored in decoded form, +// use [URL.EscapedFragment] to retrieve the original encoding. // -// The RawPath field is an optional field which is only set when the default -// encoding of Path is different from the escaped path. See the EscapedPath method -// for more details. -// -// URL's String method uses the EscapedPath method to obtain the path. +// The [URL.String] method uses the [URL.EscapedPath] method to obtain the path. type URL struct { - Scheme string - Opaque string // encoded opaque data - User *Userinfo // username and password information - Host string // host or host:port (see Hostname and Port methods) - Path string // path (relative paths may omit leading slash) - RawPath string // encoded path hint (see EscapedPath method) - OmitHost bool // do not emit empty host (authority) - ForceQuery bool // append a query ('?') even if RawQuery is empty - RawQuery string // encoded query values, without '?' - Fragment string // fragment for references, without '#' - RawFragment string // encoded fragment hint (see EscapedFragment method) + Scheme string + Opaque string // encoded opaque data + User *Userinfo // username and password information + Host string // "host" or "host:port" (see Hostname and Port methods) + Path string // path (relative paths may omit leading slash) + Fragment string // fragment for references (without '#') + + // RawQuery contains the encoded query values, without the initial '?'. + // Use URL.Query to decode the query. + RawQuery string + + // RawPath is an optional field containing an encoded path hint. + // See the EscapedPath method for more details. + // + // In general, code should call EscapedPath instead of reading RawPath. + RawPath string + + // RawFragment is an optional field containing an encoded fragment hint. + // See the EscapedFragment method for more details. + // + // In general, code should call EscapedFragment instead of reading RawFragment. + RawFragment string + + // ForceQuery indicates whether the original URL contained a query ('?') character. + // When set, the String method will include a trailing '?', even when RawQuery is empty. + ForceQuery bool + + // OmitHost indicates the URL has an empty host (authority). + // When set, the String method will not include the host when it is empty. + OmitHost bool } // User returns a [Userinfo] containing the provided username From 3a05e7b0325eb71fede880f67db63d192f2fa0e1 Mon Sep 17 00:00:00 2001 From: Oliver Eikemeier Date: Sun, 5 Oct 2025 11:57:40 +0000 Subject: [PATCH 060/229] spec: close tag Close an "a" tag. While we are here, fix some escapes. Change-Id: I16040eff0d4beeef6230aec8fcf4315f0efd13a4 GitHub-Last-Rev: 3ba7b9f7478f54338bd3ca7ac55cc2ad1ffcb3a4 GitHub-Pull-Request: golang/go#75760 Reviewed-on: https://go-review.googlesource.com/c/go/+/708517 Reviewed-by: Sean Liao LUCI-TryBot-Result: Go LUCI Reviewed-by: Cherry Mui Reviewed-by: Emmanuel Odeke Reviewed-by: Robert Findley Auto-Submit: Sean Liao --- doc/go_spec.html | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/doc/go_spec.html b/doc/go_spec.html index 92afe1cee0baef..d6c7962a961b88 100644 --- a/doc/go_spec.html +++ b/doc/go_spec.html @@ -3173,7 +3173,7 @@

Composite literals

Unless the LiteralType is a type parameter, -its underlying type +its underlying type must be a struct, array, slice, or map type (the syntax enforces this constraint except when the type is given as a TypeName). @@ -4873,7 +4873,7 @@

Operator precedence

x <= f() // x <= f() ^a >> b // (^a) >> b f() || g() // f() || g() -x == y+1 && <-chanInt > 0 // (x == (y+1)) && ((<-chanInt) > 0) +x == y+1 && <-chanInt > 0 // (x == (y+1)) && ((<-chanInt) > 0) @@ -6635,7 +6635,7 @@

For statements with for clause

 var prints []func()
-for i := 0; i < 5; i++ {
+for i := 0; i < 5; i++ {
 	prints = append(prints, func() { println(i) })
 	i++
 }
@@ -6772,7 +6772,7 @@ 
For statements with range clause

 variable, which must be of integer type.
 Otherwise, if the iteration variable is declared by the "range" clause or is absent,
 the type of the iteration values is the default type for n.
-If n <= 0, the loop does not run any iterations.
+If n <= 0, the loop does not run any iterations.
 
 
 
  • 
@@ -7799,7 +7799,7 @@ 
    Min and max
    
 
    
 
 
    -min(x, y)    == if x <= y then x else y
+min(x, y)    == if x <= y then x else y
 min(x, y, z) == min(min(x, y), z)
 
    
 

From e74b224b7c7b7511fe37686d81a6e33d40fdeb17 Mon Sep 17 00:00:00 2001
From: Daniel McCarney 
Date: Fri, 11 Jul 2025 10:42:22 -0400
Subject: [PATCH 061/229] crypto/tls: streamline BoGo testing w/
 -bogo-local-dir

If -bogo-local-dir is provided but doesn't exist, populate it with a git
checkout of the BoringSSL repo at the correct SHA.

Without any -bogo-local-dir argument the BoGo TLS handshake test will
fetch the BoringSSL source at a specific SHA as a Go module in a r/o
module directory. When debugging, or extending BoGo coverage, it's
preferable to have a mutable local copy of BoGo that the test will
use.

The pre-existing -bogo-local-dir flag offered a way to use a checkout of
BoGo but it relied on the user fetching the correct repo & revision
manually ahead of time. This commit extends the test to automatically
invoke `git` to clone the repo into the provided local dir at the
correct SHA based on the boringsslModVer const if the local dir doesn't
exist.

This leaves the user ready to make changes in local BoGo dir to aid
debugging, or to upstream as CRs to BoringSSL, and prevents using an
incorrect SHA by mistake.

Updates #72006

Change-Id: I0451a3d35203878cdf02a7587e138c3cd60d15a9
Reviewed-on: https://go-review.googlesource.com/c/go/+/687475
Reviewed-by: Roland Shoemaker 
Reviewed-by: Carlos Amedee 
TryBot-Bypass: Daniel McCarney 
---
 src/crypto/tls/bogo_shim_test.go | 46 ++++++++++++++++++++++++++++++++
 src/crypto/tls/handshake_test.go |  5 ++--
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/src/crypto/tls/bogo_shim_test.go b/src/crypto/tls/bogo_shim_test.go
index f3f19b34e9e4cc..8f171d925959c8 100644
--- a/src/crypto/tls/bogo_shim_test.go
+++ b/src/crypto/tls/bogo_shim_test.go
@@ -11,6 +11,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"encoding/pem"
+	"errors"
 	"flag"
 	"fmt"
 	"html/template"
@@ -541,6 +542,7 @@ func orderlyShutdown(tlsConn *Conn) {
 }
 
 func TestBogoSuite(t *testing.T) {
+	testenv.MustHaveGoBuild(t)
 	if testing.Short() {
 		t.Skip("skipping in short mode")
 	}
@@ -559,6 +561,7 @@ func TestBogoSuite(t *testing.T) {
 
 	var bogoDir string
 	if *bogoLocalDir != "" {
+		ensureLocalBogo(t, *bogoLocalDir)
 		bogoDir = *bogoLocalDir
 	} else {
 		bogoDir = cryptotest.FetchModule(t, "boringssl.googlesource.com/boringssl.git", boringsslModVer)
@@ -664,6 +667,49 @@ func TestBogoSuite(t *testing.T) {
 	}
 }
 
+// ensureLocalBogo fetches BoringSSL to localBogoDir at the correct revision
+// (from boringsslModVer) if localBogoDir doesn't already exist.
+//
+// If localBogoDir does exist, ensureLocalBogo fails the test if it isn't
+// a directory.
+func ensureLocalBogo(t *testing.T, localBogoDir string) {
+	t.Helper()
+
+	if stat, err := os.Stat(localBogoDir); err == nil {
+		if !stat.IsDir() {
+			t.Fatalf("local bogo dir (%q) exists but is not a directory", localBogoDir)
+		}
+
+		t.Logf("using local bogo checkout from %q", localBogoDir)
+		return
+	} else if !errors.Is(err, os.ErrNotExist) {
+		t.Fatalf("failed to stat local bogo dir (%q): %v", localBogoDir, err)
+	}
+
+	testenv.MustHaveExecPath(t, "git")
+
+	idx := strings.LastIndex(boringsslModVer, "-")
+	if idx == -1 || idx == len(boringsslModVer)-1 {
+		t.Fatalf("invalid boringsslModVer format: %q", boringsslModVer)
+	}
+	commitSHA := boringsslModVer[idx+1:]
+
+	t.Logf("cloning boringssl@%s to %q", commitSHA, localBogoDir)
+	cloneCmd := testenv.Command(t, "git", "clone", "--no-checkout", "https://boringssl.googlesource.com/boringssl", localBogoDir)
+	if err := cloneCmd.Run(); err != nil {
+		t.Fatalf("git clone failed: %v", err)
+	}
+
+	checkoutCmd := testenv.Command(t, "git", "checkout", commitSHA)
+	checkoutCmd.Dir = localBogoDir
+	if err := checkoutCmd.Run(); err != nil {
+		t.Fatalf("git checkout failed: %v", err)
+	}
+
+	t.Logf("using fresh local bogo checkout from %q", localBogoDir)
+	return
+}
+
 func generateReport(results bogoResults, outPath string) error {
 	data := reportData{
 		Results:   results,
diff --git a/src/crypto/tls/handshake_test.go b/src/crypto/tls/handshake_test.go
index 13f1bb1dd50a19..3e2c5663087828 100644
--- a/src/crypto/tls/handshake_test.go
+++ b/src/crypto/tls/handshake_test.go
@@ -46,8 +46,9 @@ var (
 	keyFile      = flag.String("keylog", "", "destination file for KeyLogWriter")
 	bogoMode     = flag.Bool("bogo-mode", false, "Enabled bogo shim mode, ignore everything else")
 	bogoFilter   = flag.String("bogo-filter", "", "BoGo test filter")
-	bogoLocalDir = flag.String("bogo-local-dir", "", "Local BoGo to use, instead of fetching from source")
-	bogoReport   = flag.String("bogo-html-report", "", "File path to render an HTML report with BoGo results")
+	bogoLocalDir = flag.String("bogo-local-dir", "",
+		"If not-present, checkout BoGo into this dir, or otherwise use it as a pre-existing checkout")
+	bogoReport = flag.String("bogo-html-report", "", "File path to render an HTML report with BoGo results")
 )
 
 func runTestAndUpdateIfNeeded(t *testing.T, name string, run func(t *testing.T, update bool), wait bool) {

From ac2ec82172799b88c057bb9ded6fe24e7909e860 Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Fri, 3 Oct 2025 16:23:10 +0000
Subject: [PATCH 062/229] runtime: bump thread count slack for
 TestReadMetricsSched

This test is *still* flaky, but it appears to be just
mayMoreStackPreempt and the thread count *occasionally* exceeds the
original (and arbitrary) thread count slack by exactly 1.

Bump the thread count slack by one. We can investigate further and bump
it again if it continues to be a problem.

Fixes #75664.

Change-Id: I29c922bba6d2cc99a8c3bf5e04cc512d0694f7fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/708868
Reviewed-by: Michael Pratt 
Auto-Submit: Michael Knyszek 
LUCI-TryBot-Result: Go LUCI 
---
 src/runtime/testdata/testprog/schedmetrics.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/runtime/testdata/testprog/schedmetrics.go b/src/runtime/testdata/testprog/schedmetrics.go
index 6d3f68a848e00a..bc0906330f1a4f 100644
--- a/src/runtime/testdata/testprog/schedmetrics.go
+++ b/src/runtime/testdata/testprog/schedmetrics.go
@@ -84,7 +84,12 @@ func SchedMetrics() {
 
 	// threadsSlack is the maximum number of threads left over
 	// from the runtime (sysmon, the template thread, etc.)
-	const threadsSlack = 4
+	// Certain build modes may also cause the creation of additional
+	// threads through frequent scheduling, like mayMoreStackPreempt.
+	// A slack of 5 is arbitrary but appears to be enough to cover
+	// the leftovers plus any inflation from scheduling-heavy build
+	// modes.
+	const threadsSlack = 5
 
 	// Make sure GC isn't running, since GC workers interfere with
 	// expected counts.

From c2fb15164bdb9d44a302771be613fbef5faa4a8e Mon Sep 17 00:00:00 2001
From: Sean Liao 
Date: Sun, 5 Oct 2025 23:17:40 +0100
Subject: [PATCH 063/229] testing/synctest: remove Run

Run (experimental) is replaced by Test.

Fixes #74012

Change-Id: I1721e1edfbcb4f1fe2159dc0430a13685b2d08c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/709355
Reviewed-by: Emmanuel Odeke 
Reviewed-by: Damien Neil 
Auto-Submit: Damien Neil 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Alan Donovan 
---
 src/testing/synctest/run.go | 16 ----------------
 1 file changed, 16 deletions(-)
 delete mode 100644 src/testing/synctest/run.go

diff --git a/src/testing/synctest/run.go b/src/testing/synctest/run.go
deleted file mode 100644
index 2e668ab8634f58..00000000000000
--- a/src/testing/synctest/run.go
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright 2025 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build goexperiment.synctest
-
-package synctest
-
-import "internal/synctest"
-
-// Run is deprecated.
-//
-// Deprecated: Use Test instead. Run will be removed in Go 1.26.
-func Run(f func()) {
-	synctest.Run(f)
-}

From 24416458c21a48d83f34d3c2242d892e002bcd6c Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 19:12:20 -0400
Subject: [PATCH 064/229] cmd/go: export type State

Export the type `State` and add global variable `LoaderState` in
preparation for refactoring usage of other global variables in the
modload package.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf 'mv state State'
rf 'add State func NewState() *State { return &State{} }'
rf 'add init.go:/NewState/+0 var LoaderState = NewState()'

Change-Id: I0ec6199ba3e05927bec12f11a60383d1b51b111a
Reviewed-on: https://go-review.googlesource.com/c/go/+/698055
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/modload/init.go | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 498ff7433ea6fe..5192fe0fc8cc58 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -96,7 +96,7 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	}
 
 	// Reset the state to a clean state.
-	oldstate := setState(state{})
+	oldstate := setState(State{})
 	ForceUseModules = true
 
 	// Load in workspace mode.
@@ -401,11 +401,11 @@ func WorkFilePath() string {
 // Reset clears all the initialized, cached state about the use of modules,
 // so that we can start over.
 func Reset() {
-	setState(state{})
+	setState(State{})
 }
 
-func setState(s state) state {
-	oldState := state{
+func setState(s State) State {
+	oldState := State{
 		initialized:     initialized,
 		forceUseModules: ForceUseModules,
 		rootMode:        RootMode,
@@ -429,7 +429,7 @@ func setState(s state) state {
 	return oldState
 }
 
-type state struct {
+type State struct {
 	initialized     bool
 	forceUseModules bool
 	rootMode        Root
@@ -441,6 +441,10 @@ type state struct {
 	modfetchState   modfetch.State
 }
 
+func NewState() *State { return &State{} }
+
+var LoaderState = NewState()
+
 // Init determines whether module mode is enabled, locates the root of the
 // current module (if any), sets environment variables for Git subprocesses, and
 // configures the cfg, codehost, load, modfetch, and search packages for use

From f3312124c2370c2f64a7f9ad29732ec30209647a Mon Sep 17 00:00:00 2001
From: Michael Pratt 
Date: Mon, 6 Oct 2025 14:38:47 -0400
Subject: [PATCH 065/229] runtime: remove batching from spanSPMC free

Added in CL 700496, freeSomeSpanSPMCs attempts to bound tail latency by
processing at most 64 entries at a time, as well as returning early if
it notices a preemption request. Both of those are attempts to reduce
tail latency, as we cannot preempt the function while it holds the lock.
This scheme is based on a similar scheme in freeSomeWbufs.

freeSomeWbufs has a key difference: all workbufs in its list are
unconditionally freed. So freeSomeWbufs will always make forward
progress in each call (unless it is constantly preempted).

In contrast, freeSomeSpanSPMCs only frees "dead" entries. If the list
contains >64 live entries, a call may make no progress, and the caller
will simply keep calling in a loop forever, until the GC ends at which
point it returns success early. The infinite loop likely restarts at the
next GC cycle.

The queues are used on each P, so it is easy to have 64 permanently live
queues if GOMAXPROCS >= 64. If GOMAXPROCS < 64, it is possible to
transiently have more queues, but spanQueue.drain increases queue size
in an attempt to reach a steady state of one queue per P.

We must drop work.spanSPMCs.lock to allow preemption, but dropping the
lock allows mutation of the linked list, meaning we cannot simply
continue iteration after retaking lock. Since there is no
straightforward resolution to this and we expect this to generally only
be around 1 entry per P, simply remove the batching and process the
entire list without preemption. We may want to revisit this in the
future for very high GOMAXPROCS or if application regularly otherwise
create very long lists.

Fixes #75771.

Change-Id: I6a6a636cd3be443aacde5a678c460aa7066b4c4a
Reviewed-on: https://go-review.googlesource.com/c/go/+/709575
Reviewed-by: Michael Knyszek 
LUCI-TryBot-Result: Go LUCI 
---
 src/runtime/mgc.go                  |  3 +--
 src/runtime/mgcmark_greenteagc.go   | 23 ++++++++++-------------
 src/runtime/mgcmark_nogreenteagc.go |  4 ++--
 src/runtime/mgcsweep.go             |  5 +----
 4 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index b13ec845fc401f..b4b4485629b59d 100644
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -2046,8 +2046,7 @@ func gcSweep(mode gcMode) bool {
 		prepareFreeWorkbufs()
 		for freeSomeWbufs(false) {
 		}
-		for freeSomeSpanSPMCs(false) {
-		}
+		freeDeadSpanSPMCs()
 		// All "free" events for this mark/sweep cycle have
 		// now happened, so we can make this profile cycle
 		// available immediately.
diff --git a/src/runtime/mgcmark_greenteagc.go b/src/runtime/mgcmark_greenteagc.go
index 3975e1e76b501c..7f8d60349ffb67 100644
--- a/src/runtime/mgcmark_greenteagc.go
+++ b/src/runtime/mgcmark_greenteagc.go
@@ -722,13 +722,8 @@ func (r *spanSPMC) slot(i uint32) *objptr {
 	return (*objptr)(unsafe.Add(unsafe.Pointer(r.ring), idx*unsafe.Sizeof(objptr(0))))
 }
 
-// freeSomeSpanSPMCs frees some spanSPMCs back to the OS and returns
-// true if it should be called again to free more.
-func freeSomeSpanSPMCs(preemptible bool) bool {
-	// TODO(mknyszek): This is arbitrary, but some kind of limit is necessary
-	// to help bound delays to cooperatively preempt ourselves.
-	const batchSize = 64
-
+// freeDeadSpanSPMCs frees dead spanSPMCs back to the OS.
+func freeDeadSpanSPMCs() {
 	// According to the SPMC memory management invariants, we can only free
 	// spanSPMCs outside of the mark phase. We ensure we do this in two ways.
 	//
@@ -740,18 +735,21 @@ func freeSomeSpanSPMCs(preemptible bool) bool {
 	//
 	// This way, we ensure that we don't start freeing if we're in the wrong
 	// phase, and the phase can't change on us while we're freeing.
+	//
+	// TODO(go.dev/issue/75771): Due to the grow semantics in
+	// spanQueue.drain, we expect a steady-state of around one spanSPMC per
+	// P, with some spikes higher when Ps have more than one. For high
+	// GOMAXPROCS, or if this list otherwise gets long, it would be nice to
+	// have a way to batch work that allows preemption during processing.
 	lock(&work.spanSPMCs.lock)
 	if gcphase != _GCoff || work.spanSPMCs.all == nil {
 		unlock(&work.spanSPMCs.lock)
-		return false
+		return
 	}
 	rp := &work.spanSPMCs.all
-	gp := getg()
-	more := true
-	for i := 0; i < batchSize && !(preemptible && gp.preempt); i++ {
+	for {
 		r := *rp
 		if r == nil {
-			more = false
 			break
 		}
 		if r.dead.Load() {
@@ -766,7 +764,6 @@ func freeSomeSpanSPMCs(preemptible bool) bool {
 		}
 	}
 	unlock(&work.spanSPMCs.lock)
-	return more
 }
 
 // tryStealSpan attempts to steal a span from another P's local queue.
diff --git a/src/runtime/mgcmark_nogreenteagc.go b/src/runtime/mgcmark_nogreenteagc.go
index 9838887f7be008..883c3451abec6b 100644
--- a/src/runtime/mgcmark_nogreenteagc.go
+++ b/src/runtime/mgcmark_nogreenteagc.go
@@ -67,8 +67,8 @@ type spanSPMC struct {
 	_ sys.NotInHeap
 }
 
-func freeSomeSpanSPMCs(preemptible bool) bool {
-	return false
+func freeDeadSpanSPMCs() {
+	return
 }
 
 type objptr uintptr
diff --git a/src/runtime/mgcsweep.go b/src/runtime/mgcsweep.go
index 364cdb58ccb0bc..c3d6afb90a54fe 100644
--- a/src/runtime/mgcsweep.go
+++ b/src/runtime/mgcsweep.go
@@ -307,10 +307,7 @@ func bgsweep(c chan int) {
 			// N.B. freeSomeWbufs is already batched internally.
 			goschedIfBusy()
 		}
-		for freeSomeSpanSPMCs(true) {
-			// N.B. freeSomeSpanSPMCs is already batched internally.
-			goschedIfBusy()
-		}
+		freeDeadSpanSPMCs()
 		lock(&sweep.lock)
 		if !isSweepDone() {
 			// This can happen if a GC runs between

From 719dfcf8a8478d70360bf3c34c0e920be7b32994 Mon Sep 17 00:00:00 2001
From: Keith Randall 
Date: Sat, 17 May 2025 15:05:56 -0700
Subject: [PATCH 066/229] cmd/compile: redo arm64 LR/FP save and restore

Instead of storing LR (the return address) at 0(SP) and the FP
(parent's frame pointer) at -8(SP), store them at framesize-8(SP)
and framesize-16(SP), respectively.

We push and pop data onto the stack such that we're never accessing
anything below SP.

The prolog/epilog lengths are unchanged (3 insns for a typical prolog,
2 for a typical epilog).

We use 8 bytes more per frame.

Typical prologue:

    STP.W   (FP, LR), -16(SP)
    MOVD    SP, FP
    SUB	    $C, SP

Typical epilogue:

    ADD     $C, SP
    LDP.P   16(SP), (FP, LR)
    RET

The previous word where we stored LR, at 0(SP), is now unused.
We could repurpose that slot for storing a local variable.

The new prolog and epilog instructions are recognized by libunwind,
so pc-sampling tools like perf should now be accurate. (TODO: except
maybe after the first RET instruction? Have to look into that.)

Update #73753 (fixes, for arm64)
Update #57302 (Quim thinks this will help on that issue)

Change-Id: I4800036a9a9a08aaaf35d9f99de79a36cf37ebb8
Reviewed-on: https://go-review.googlesource.com/c/go/+/674615
Reviewed-by: David Chase 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/abi-internal.md               |  12 +-
 src/cmd/compile/internal/arm64/ggen.go        |  10 +-
 src/cmd/compile/internal/arm64/ssa.go         |   2 +-
 src/cmd/compile/internal/ssagen/pgen.go       |   6 +
 src/cmd/compile/internal/ssagen/ssa.go        |   3 +-
 src/cmd/internal/obj/arm64/asm7.go            |  12 +-
 src/cmd/internal/obj/arm64/obj7.go            | 326 ++++++------------
 src/cmd/link/internal/amd64/obj.go            |  19 +-
 src/cmd/link/internal/arm64/obj.go            |  23 +-
 src/cmd/link/internal/ld/dwarf.go             |   7 +-
 src/cmd/link/internal/ld/lib.go               |   4 +
 src/cmd/link/internal/ld/stackcheck.go        |   5 -
 src/cmd/link/internal/x86/obj.go              |  15 +-
 src/runtime/asm_arm64.s                       |  81 ++++-
 src/runtime/mkpreempt.go                      |  20 +-
 src/runtime/panic.go                          |   8 +-
 src/runtime/preempt_arm64.s                   |  15 +-
 src/runtime/race_arm64.s                      |  17 +-
 src/runtime/signal_arm64.go                   |  16 +-
 src/runtime/stack.go                          |  20 +-
 src/runtime/testdata/testprog/badtraceback.go |   5 +
 src/runtime/traceback.go                      |  30 +-
 test/nosplit.go                               |   8 +-
 23 files changed, 303 insertions(+), 361 deletions(-)

diff --git a/src/cmd/compile/abi-internal.md b/src/cmd/compile/abi-internal.md
index eae230dc070d86..490e1affb74de9 100644
--- a/src/cmd/compile/abi-internal.md
+++ b/src/cmd/compile/abi-internal.md
@@ -576,19 +576,19 @@ A function's stack frame, after the frame is created, is laid out as
 follows:
 
     +------------------------------+
+    | return PC                    |
+    | frame pointer on entry       | ← R29 points to
     | ... locals ...               |
     | ... outgoing arguments ...   |
-    | return PC                    | ← RSP points to
-    | frame pointer on entry       |
+    | unused word                  | ← RSP points to
     +------------------------------+ ↓ lower addresses
 
 The "return PC" is loaded to the link register, R30, as part of the
 arm64 `CALL` operation.
 
-On entry, a function subtracts from RSP to open its stack frame, and
-saves the values of R30 and R29 at the bottom of the frame.
-Specifically, R30 is saved at 0(RSP) and R29 is saved at -8(RSP),
-after RSP is updated.
+On entry, a function pushes R30 (the return address) and R29
+(the caller's frame pointer) onto the bottom of the stack. It then
+subtracts a constant from RSP to open its stack frame.
 
 A leaf function that does not require any stack space may omit the
 saved R30 and R29.
diff --git a/src/cmd/compile/internal/arm64/ggen.go b/src/cmd/compile/internal/arm64/ggen.go
index 14027467002a3e..6ba56b992eeda6 100644
--- a/src/cmd/compile/internal/arm64/ggen.go
+++ b/src/cmd/compile/internal/arm64/ggen.go
@@ -11,10 +11,12 @@ import (
 )
 
 func padframe(frame int64) int64 {
-	// arm64 requires that the frame size (not counting saved FP&LR)
-	// be 16 bytes aligned. If not, pad it.
-	if frame%16 != 0 {
-		frame += 16 - (frame % 16)
+	// arm64 requires frame sizes here that are 8 mod 16.
+	// With the additional (unused) slot at the bottom of the frame,
+	// that makes an aligned 16 byte frame.
+	// Adding a save region for LR+FP does not change the alignment.
+	if frame != 0 {
+		frame += (-(frame + 8)) & 15
 	}
 	return frame
 }
diff --git a/src/cmd/compile/internal/arm64/ssa.go b/src/cmd/compile/internal/arm64/ssa.go
index 7bc0e536e941e6..9f79a740c6ca81 100644
--- a/src/cmd/compile/internal/arm64/ssa.go
+++ b/src/cmd/compile/internal/arm64/ssa.go
@@ -221,7 +221,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 
 		for i := 0; i < len(args); i++ {
 			a := args[i]
-			// Offset by size of the saved LR slot.
+			// Offset by size of the unused slot before start of args.
 			addr := ssagen.SpillSlotAddr(a, arm64.REGSP, base.Ctxt.Arch.FixedFrameSize)
 			// Look for double-register operations if we can.
 			if i < len(args)-1 {
diff --git a/src/cmd/compile/internal/ssagen/pgen.go b/src/cmd/compile/internal/ssagen/pgen.go
index 0a2010363f8d04..f0776172b9264a 100644
--- a/src/cmd/compile/internal/ssagen/pgen.go
+++ b/src/cmd/compile/internal/ssagen/pgen.go
@@ -393,10 +393,16 @@ func StackOffset(slot ssa.LocalSlot) int32 {
 	case ir.PAUTO:
 		off = n.FrameOffset()
 		if base.Ctxt.Arch.FixedFrameSize == 0 {
+			// x86 return address
 			off -= int64(types.PtrSize)
 		}
 		if buildcfg.FramePointerEnabled {
+			// frame pointer
 			off -= int64(types.PtrSize)
+			if buildcfg.GOARCH == "arm64" {
+				// arm64 return address also
+				off -= int64(types.PtrSize)
+			}
 		}
 	}
 	return int32(off + slot.Off)
diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 1e2159579dfbf2..107447f04cc4f6 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -7150,6 +7150,7 @@ func defframe(s *State, e *ssafn, f *ssa.Func) {
 	// Insert code to zero ambiguously live variables so that the
 	// garbage collector only sees initialized values when it
 	// looks for pointers.
+	// Note: lo/hi are offsets from varp and will be negative.
 	var lo, hi int64
 
 	// Opaque state for backend to use. Current backends use it to
@@ -7157,7 +7158,7 @@ func defframe(s *State, e *ssafn, f *ssa.Func) {
 	var state uint32
 
 	// Iterate through declarations. Autos are sorted in decreasing
-	// frame offset order.
+	// frame offset order (least negative to most negative).
 	for _, n := range e.curfn.Dcl {
 		if !n.Needzero() {
 			continue
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index 743d09a319087d..281d705a3eb614 100644
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -51,7 +51,6 @@ type ctxt7 struct {
 	blitrl     *obj.Prog
 	elitrl     *obj.Prog
 	autosize   int32
-	extrasize  int32
 	instoffset int64
 	pc         int64
 	pool       struct {
@@ -1122,8 +1121,7 @@ func span7(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 		ctxt.Diag("arm64 ops not initialized, call arm64.buildop first")
 	}
 
-	c := ctxt7{ctxt: ctxt, newprog: newprog, cursym: cursym, autosize: int32(p.To.Offset & 0xffffffff), extrasize: int32(p.To.Offset >> 32)}
-	p.To.Offset &= 0xffffffff // extrasize is no longer needed
+	c := ctxt7{ctxt: ctxt, newprog: newprog, cursym: cursym, autosize: int32(p.To.Offset)}
 
 	// Process literal pool and allocate initial program counter for each Prog, before
 	// generating branch veneers.
@@ -2119,8 +2117,8 @@ func (c *ctxt7) aclass(a *obj.Addr) int {
 				// a.Offset is still relative to pseudo-SP.
 				a.Reg = obj.REG_NONE
 			}
-			// The frame top 8 or 16 bytes are for FP
-			c.instoffset = int64(c.autosize) + a.Offset - int64(c.extrasize)
+			// The frame top 16 bytes are for LR/FP
+			c.instoffset = int64(c.autosize) + a.Offset - extrasize
 			return autoclass(c.instoffset)
 
 		case obj.NAME_PARAM:
@@ -2180,8 +2178,8 @@ func (c *ctxt7) aclass(a *obj.Addr) int {
 				// a.Offset is still relative to pseudo-SP.
 				a.Reg = obj.REG_NONE
 			}
-			// The frame top 8 or 16 bytes are for FP
-			c.instoffset = int64(c.autosize) + a.Offset - int64(c.extrasize)
+			// The frame top 16 bytes are for LR/FP
+			c.instoffset = int64(c.autosize) + a.Offset - extrasize
 
 		case obj.NAME_PARAM:
 			if a.Reg == REGSP {
diff --git a/src/cmd/internal/obj/arm64/obj7.go b/src/cmd/internal/obj/arm64/obj7.go
index 2583e46354292f..a697426145185b 100644
--- a/src/cmd/internal/obj/arm64/obj7.go
+++ b/src/cmd/internal/obj/arm64/obj7.go
@@ -36,7 +36,6 @@ import (
 	"cmd/internal/src"
 	"cmd/internal/sys"
 	"internal/abi"
-	"internal/buildcfg"
 	"log"
 	"math"
 )
@@ -472,6 +471,8 @@ func (c *ctxt7) rewriteToUseGot(p *obj.Prog) {
 	obj.Nopout(p)
 }
 
+const extrasize = 16 // space needed in the frame for LR+FP
+
 func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 	if cursym.Func().Text == nil || cursym.Func().Text.Link == nil {
 		return
@@ -521,33 +522,26 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			c.autosize = int32(textstksiz)
 
 			if p.Mark&LEAF != 0 && c.autosize == 0 {
-				// A leaf function with no locals has no frame.
+				// A leaf function with no locals needs no frame.
 				p.From.Sym.Set(obj.AttrNoFrame, true)
 			}
 
 			if !p.From.Sym.NoFrame() {
 				// If there is a stack frame at all, it includes
-				// space to save the LR.
+				// space for the (now unused) word at [SP:SP+8].
 				c.autosize += 8
 			}
 
+			// Round up to a multiple of 16.
+			c.autosize += (-c.autosize) & 15
+
 			if c.autosize != 0 {
-				extrasize := int32(0)
-				if c.autosize%16 == 8 {
-					// Allocate extra 8 bytes on the frame top to save FP
-					extrasize = 8
-				} else if c.autosize&(16-1) == 0 {
-					// Allocate extra 16 bytes to save FP for the old frame whose size is 8 mod 16
-					extrasize = 16
-				} else {
-					c.ctxt.Diag("%v: unaligned frame size %d - must be 16 aligned", p, c.autosize-8)
-				}
+				// Allocate an extra 16 bytes at the top of the frame
+				// to save LR+FP.
 				c.autosize += extrasize
 				c.cursym.Func().Locals += extrasize
 
-				// low 32 bits for autosize
-				// high 32 bits for extrasize
-				p.To.Offset = int64(c.autosize) | int64(extrasize)<<32
+				p.To.Offset = int64(c.autosize)
 			} else {
 				// NOFRAME
 				p.To.Offset = 0
@@ -580,120 +574,72 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			var prologueEnd *obj.Prog
 
 			aoffset := c.autosize
-			if aoffset > 0xf0 {
-				// MOVD.W offset variant range is -0x100 to 0xf8, SP should be 16-byte aligned.
-				// so the maximum aoffset value is 0xf0.
-				aoffset = 0xf0
+			if aoffset < 16 {
+				log.Fatalf("aoffset too small %d", aoffset)
 			}
 
-			// Frame is non-empty. Make sure to save link register, even if
-			// it is a leaf function, so that traceback works.
 			q = p
-			if c.autosize > aoffset {
-				// Frame size is too large for a MOVD.W instruction. Store the frame pointer
-				// register and link register before decrementing SP, so if a signal comes
-				// during the execution of the function prologue, the traceback code will
-				// not see a half-updated stack frame.
-
-				// SUB $autosize, RSP, R20
-				q1 = obj.Appendp(q, c.newprog)
-				q1.Pos = p.Pos
-				q1.As = ASUB
-				q1.From.Type = obj.TYPE_CONST
-				q1.From.Offset = int64(c.autosize)
-				q1.Reg = REGSP
-				q1.To.Type = obj.TYPE_REG
-				q1.To.Reg = REG_R20
-
-				prologueEnd = q1
-
-				// STP (R29, R30), -8(R20)
-				q1 = obj.Appendp(q1, c.newprog)
-				q1.Pos = p.Pos
-				q1.As = ASTP
-				q1.From.Type = obj.TYPE_REGREG
-				q1.From.Reg = REGFP
-				q1.From.Offset = REGLINK
-				q1.To.Type = obj.TYPE_MEM
-				q1.To.Reg = REG_R20
-				q1.To.Offset = -8
-
-				// This is not async preemptible, as if we open a frame
-				// at the current SP, it will clobber the saved LR.
-				q1 = c.ctxt.StartUnsafePoint(q1, c.newprog)
-
-				// MOVD R20, RSP
-				q1 = obj.Appendp(q1, c.newprog)
-				q1.Pos = p.Pos
-				q1.As = AMOVD
-				q1.From.Type = obj.TYPE_REG
-				q1.From.Reg = REG_R20
-				q1.To.Type = obj.TYPE_REG
-				q1.To.Reg = REGSP
-				q1.Spadj = c.autosize
-
-				q1 = c.ctxt.EndUnsafePoint(q1, c.newprog, -1)
-
-				if buildcfg.GOOS == "ios" {
-					// iOS does not support SA_ONSTACK. We will run the signal handler
-					// on the G stack. If we write below SP, it may be clobbered by
-					// the signal handler. So we save FP and LR after decrementing SP.
-					// STP (R29, R30), -8(RSP)
+
+			// Store return address and frame pointer at the top of the stack frame.
+			// STP.W (R29, R30), -16(SP)
+			q1 = obj.Appendp(q, c.newprog)
+			q1.Pos = p.Pos
+			q1.As = ASTP
+			q1.From.Type = obj.TYPE_REGREG
+			q1.From.Reg = REGFP
+			q1.From.Offset = REGLINK
+			q1.To.Type = obj.TYPE_MEM
+			q1.To.Reg = REG_RSP
+			q1.To.Offset = -16
+			q1.Scond = C_XPRE
+
+			prologueEnd = q1
+
+			// Update frame pointer
+			q1 = obj.Appendp(q1, c.newprog)
+			q1.Pos = p.Pos
+			q1.As = AMOVD
+			q1.From.Type = obj.TYPE_REG
+			q1.From.Reg = REGSP
+			q1.To.Type = obj.TYPE_REG
+			q1.To.Reg = REGFP
+
+			// Allocate additional frame space.
+			adj := aoffset - 16
+			if adj > 0 {
+				// SUB $autosize-16, RSP
+				if adj < 1<<12 {
+					q1 = obj.Appendp(q1, c.newprog)
+					q1.Pos = p.Pos
+					q1.As = ASUB
+					q1.From.Type = obj.TYPE_CONST
+					q1.From.Offset = int64(adj)
+					q1.To.Type = obj.TYPE_REG
+					q1.To.Reg = REGSP
+				} else {
+					// Constant too big for atomic subtract.
+					// Materialize in tmp register first.
+					q1 = obj.Appendp(q1, c.newprog)
+					q1.Pos = p.Pos
+					q1.As = AMOVD
+					q1.From.Type = obj.TYPE_CONST
+					q1.From.Offset = int64(adj)
+					q1.To.Type = obj.TYPE_REG
+					q1.To.Reg = REGTMP
+
 					q1 = obj.Appendp(q1, c.newprog)
 					q1.Pos = p.Pos
-					q1.As = ASTP
-					q1.From.Type = obj.TYPE_REGREG
-					q1.From.Reg = REGFP
-					q1.From.Offset = REGLINK
-					q1.To.Type = obj.TYPE_MEM
+					q1.As = ASUB
+					q1.From.Type = obj.TYPE_REG
+					q1.From.Reg = REGTMP
+					q1.To.Type = obj.TYPE_REG
 					q1.To.Reg = REGSP
-					q1.To.Offset = -8
 				}
-			} else {
-				// small frame, update SP and save LR in a single MOVD.W instruction.
-				// So if a signal comes during the execution of the function prologue,
-				// the traceback code will not see a half-updated stack frame.
-				// Also, on Linux, in a cgo binary we may get a SIGSETXID signal
-				// early on before the signal stack is set, as glibc doesn't allow
-				// us to block SIGSETXID. So it is important that we don't write below
-				// the SP until the signal stack is set.
-				// Luckily, all the functions from thread entry to setting the signal
-				// stack have small frames.
-				q1 = obj.Appendp(q, c.newprog)
-				q1.As = AMOVD
-				q1.Pos = p.Pos
-				q1.From.Type = obj.TYPE_REG
-				q1.From.Reg = REGLINK
-				q1.To.Type = obj.TYPE_MEM
-				q1.Scond = C_XPRE
-				q1.To.Offset = int64(-aoffset)
-				q1.To.Reg = REGSP
-				q1.Spadj = aoffset
-
-				prologueEnd = q1
-
-				// Frame pointer.
-				q1 = obj.Appendp(q1, c.newprog)
-				q1.Pos = p.Pos
-				q1.As = AMOVD
-				q1.From.Type = obj.TYPE_REG
-				q1.From.Reg = REGFP
-				q1.To.Type = obj.TYPE_MEM
-				q1.To.Reg = REGSP
-				q1.To.Offset = -8
+				q1.Spadj = adj
 			}
 
 			prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
 
-			q1 = obj.Appendp(q1, c.newprog)
-			q1.Pos = p.Pos
-			q1.As = ASUB
-			q1.From.Type = obj.TYPE_CONST
-			q1.From.Offset = 8
-			q1.Reg = REGSP
-			q1.To.Type = obj.TYPE_REG
-			q1.To.Reg = REGFP
-
 		case obj.ARET:
 			nocache(p)
 			if p.From.Type == obj.TYPE_CONST {
@@ -707,105 +653,56 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			}
 			p.To = obj.Addr{}
 			aoffset := c.autosize
-			if c.cursym.Func().Text.Mark&LEAF != 0 {
-				if aoffset != 0 {
-					// Restore frame pointer.
-					// ADD $framesize-8, RSP, R29
-					p.As = AADD
-					p.From.Type = obj.TYPE_CONST
-					p.From.Offset = int64(c.autosize) - 8
-					p.Reg = REGSP
-					p.To.Type = obj.TYPE_REG
-					p.To.Reg = REGFP
-
-					// Pop stack frame.
-					// ADD $framesize, RSP, RSP
-					p = obj.Appendp(p, c.newprog)
-					p.As = AADD
-					p.From.Type = obj.TYPE_CONST
-					p.From.Offset = int64(c.autosize)
-					p.To.Type = obj.TYPE_REG
-					p.To.Reg = REGSP
-					p.Spadj = -c.autosize
+			if aoffset > 0 {
+				if aoffset < 16 {
+					log.Fatalf("aoffset too small %d", aoffset)
+				}
+				adj := aoffset - 16
+				if adj > 0 {
+					if adj < 1<<12 {
+						// ADD $adj, RSP, RSP
+						p.As = AADD
+						p.From.Type = obj.TYPE_CONST
+						p.From.Offset = int64(adj)
+						p.To.Type = obj.TYPE_REG
+						p.To.Reg = REGSP
+					} else {
+						// Put frame size in a separate register and
+						// add it in with a single instruction,
+						// so we never have a partial frame during
+						// the epilog. See issue 73259.
+
+						// MOVD $adj, REGTMP
+						p.As = AMOVD
+						p.From.Type = obj.TYPE_CONST
+						p.From.Offset = int64(adj)
+						p.To.Type = obj.TYPE_REG
+						p.To.Reg = REGTMP
+						// ADD REGTMP, RSP, RSP
+						p = obj.Appendp(p, c.newprog)
+						p.As = AADD
+						p.From.Type = obj.TYPE_REG
+						p.From.Reg = REGTMP
+						p.To.Type = obj.TYPE_REG
+						p.To.Reg = REGSP
+					}
+					p.Spadj = -adj
 				}
-			} else if aoffset <= 0xF0 {
-				// small frame, restore LR and update SP in a single MOVD.P instruction.
-				// There is no correctness issue to use a single LDP for LR and FP,
-				// but the instructions are not pattern matched with the prologue's
-				// MOVD.W and MOVD, which may cause performance issue in
-				// store-forwarding.
-
-				// MOVD -8(RSP), R29
-				p.As = AMOVD
-				p.From.Type = obj.TYPE_MEM
-				p.From.Reg = REGSP
-				p.From.Offset = -8
-				p.To.Type = obj.TYPE_REG
-				p.To.Reg = REGFP
-				p = obj.Appendp(p, c.newprog)
 
-				// MOVD.P offset(RSP), R30
-				p.As = AMOVD
-				p.From.Type = obj.TYPE_MEM
-				p.Scond = C_XPOST
-				p.From.Offset = int64(aoffset)
-				p.From.Reg = REGSP
-				p.To.Type = obj.TYPE_REG
-				p.To.Reg = REGLINK
-				p.Spadj = -aoffset
-			} else {
-				// LDP -8(RSP), (R29, R30)
+				// Pop LR+FP.
+				// LDP.P 16(RSP), (R29, R30)
+				if p.As != obj.ARET {
+					p = obj.Appendp(p, c.newprog)
+				}
 				p.As = ALDP
 				p.From.Type = obj.TYPE_MEM
-				p.From.Offset = -8
 				p.From.Reg = REGSP
+				p.From.Offset = 16
+				p.Scond = C_XPOST
 				p.To.Type = obj.TYPE_REGREG
 				p.To.Reg = REGFP
 				p.To.Offset = REGLINK
-
-				if aoffset < 1<<12 {
-					// ADD $aoffset, RSP, RSP
-					q = newprog()
-					q.As = AADD
-					q.From.Type = obj.TYPE_CONST
-					q.From.Offset = int64(aoffset)
-					q.To.Type = obj.TYPE_REG
-					q.To.Reg = REGSP
-					q.Spadj = -aoffset
-					q.Pos = p.Pos
-					q.Link = p.Link
-					p.Link = q
-					p = q
-				} else {
-					// Put frame size in a separate register and
-					// add it in with a single instruction,
-					// so we never have a partial frame during
-					// the epilog. See issue 73259.
-
-					// MOVD $aoffset, REGTMP
-					q = newprog()
-					q.As = AMOVD
-					q.From.Type = obj.TYPE_CONST
-					q.From.Offset = int64(aoffset)
-					q.To.Type = obj.TYPE_REG
-					q.To.Reg = REGTMP
-					q.Pos = p.Pos
-					q.Link = p.Link
-					p.Link = q
-					p = q
-					// ADD REGTMP, RSP, RSP
-					q = newprog()
-					q.As = AADD
-					q.From.Type = obj.TYPE_REG
-					q.From.Reg = REGTMP
-					q.To.Type = obj.TYPE_REG
-					q.To.Reg = REGSP
-					q.Spadj = -aoffset
-					q.Pos = p.Pos
-					q.Link = p.Link
-					p.Link = q
-					p = q
-				}
+				p.Spadj = -16
 			}
 
 			// If enabled, this code emits 'MOV PC, R27' before every 'MOV LR, PC',
@@ -868,10 +765,11 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 				p.From.Type = obj.TYPE_REG
 				p.From.Reg = REGLINK
 			} else {
-				/* MOVD (RSP), Rd */
+				/* MOVD framesize-8(RSP), Rd */
 				p.As = AMOVD
 				p.From.Type = obj.TYPE_MEM
 				p.From.Reg = REGSP
+				p.From.Offset = int64(c.autosize - 8)
 			}
 		}
 		if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 {
@@ -906,6 +804,12 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			p.From.Reg = int16(REG_LSL + r + (shift&7)<<5)
 			p.From.Offset = 0
 		}
+		if p.To.Type == obj.TYPE_MEM && p.To.Reg == REG_RSP && (p.Scond == C_XPRE || p.Scond == C_XPOST) {
+			p.Spadj += int32(-p.To.Offset)
+		}
+		if p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_RSP && (p.Scond == C_XPRE || p.Scond == C_XPOST) {
+			p.Spadj += int32(-p.From.Offset)
+		}
 	}
 }
 
diff --git a/src/cmd/link/internal/amd64/obj.go b/src/cmd/link/internal/amd64/obj.go
index 3a6141b9091eb6..761496549f93aa 100644
--- a/src/cmd/link/internal/amd64/obj.go
+++ b/src/cmd/link/internal/amd64/obj.go
@@ -51,15 +51,16 @@ func Init() (*sys.Arch, ld.Arch) {
 		Plan9Magic:  uint32(4*26*26 + 7),
 		Plan9_64Bit: true,
 
-		Adddynrel:        adddynrel,
-		Archinit:         archinit,
-		Archreloc:        archreloc,
-		Archrelocvariant: archrelocvariant,
-		Gentext:          gentext,
-		Machoreloc1:      machoreloc1,
-		MachorelocSize:   8,
-		PEreloc1:         pereloc1,
-		TLSIEtoLE:        tlsIEtoLE,
+		Adddynrel:                 adddynrel,
+		Archinit:                  archinit,
+		Archreloc:                 archreloc,
+		Archrelocvariant:          archrelocvariant,
+		Gentext:                   gentext,
+		Machoreloc1:               machoreloc1,
+		MachorelocSize:            8,
+		PEreloc1:                  pereloc1,
+		TLSIEtoLE:                 tlsIEtoLE,
+		ReturnAddressAtTopOfFrame: true,
 
 		ELF: ld.ELFArch{
 			Linuxdynld:     "/lib64/ld-linux-x86-64.so.2",
diff --git a/src/cmd/link/internal/arm64/obj.go b/src/cmd/link/internal/arm64/obj.go
index 3d358155badbca..e1e4ade81835c6 100644
--- a/src/cmd/link/internal/arm64/obj.go
+++ b/src/cmd/link/internal/arm64/obj.go
@@ -47,17 +47,18 @@ func Init() (*sys.Arch, ld.Arch) {
 		Dwarfreglr: dwarfRegLR,
 		TrampLimit: 0x7c00000, // 26-bit signed offset * 4, leave room for PLT etc.
 
-		Adddynrel:        adddynrel,
-		Archinit:         archinit,
-		Archreloc:        archreloc,
-		Archrelocvariant: archrelocvariant,
-		Extreloc:         extreloc,
-		Gentext:          gentext,
-		GenSymsLate:      gensymlate,
-		Machoreloc1:      machoreloc1,
-		MachorelocSize:   8,
-		PEreloc1:         pereloc1,
-		Trampoline:       trampoline,
+		Adddynrel:                 adddynrel,
+		Archinit:                  archinit,
+		Archreloc:                 archreloc,
+		Archrelocvariant:          archrelocvariant,
+		Extreloc:                  extreloc,
+		Gentext:                   gentext,
+		GenSymsLate:               gensymlate,
+		Machoreloc1:               machoreloc1,
+		MachorelocSize:            8,
+		PEreloc1:                  pereloc1,
+		Trampoline:                trampoline,
+		ReturnAddressAtTopOfFrame: true,
 
 		ELF: ld.ELFArch{
 			Androiddynld:   "/system/bin/linker64",
diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index 0003938ef2e036..c4d12a5488df3c 100644
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -1544,9 +1544,14 @@ func (d *dwctxt) writeframes(fs loader.Sym) dwarfSecInfo {
 				if pcsp.Value > 0 {
 					// The return address is preserved at (CFA-frame_size)
 					// after a stack frame has been allocated.
+					off := -spdelta
+					if thearch.ReturnAddressAtTopOfFrame {
+						// Except arm64, which has it at the top of frame.
+						off = -int64(d.arch.PtrSize)
+					}
 					deltaBuf = append(deltaBuf, dwarf.DW_CFA_offset_extended_sf)
 					deltaBuf = dwarf.AppendUleb128(deltaBuf, uint64(thearch.Dwarfreglr))
-					deltaBuf = dwarf.AppendSleb128(deltaBuf, -spdelta/dataAlignmentFactor)
+					deltaBuf = dwarf.AppendSleb128(deltaBuf, off/dataAlignmentFactor)
 				} else {
 					// The return address is restored into the link register
 					// when a stack frame has been de-allocated.
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 2c861129b52f9a..5f5ebfc1d9855c 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -263,6 +263,10 @@ type Arch struct {
 	// optional override for assignAddress
 	AssignAddress func(ldr *loader.Loader, sect *sym.Section, n int, s loader.Sym, va uint64, isTramp bool) (*sym.Section, int, uint64)
 
+	// Reports whether the return address is stored at the top (highest address)
+	// of the stack frame.
+	ReturnAddressAtTopOfFrame bool
+
 	// ELF specific information.
 	ELF ELFArch
 }
diff --git a/src/cmd/link/internal/ld/stackcheck.go b/src/cmd/link/internal/ld/stackcheck.go
index 98e7edaeb1477b..14cd3a22384f88 100644
--- a/src/cmd/link/internal/ld/stackcheck.go
+++ b/src/cmd/link/internal/ld/stackcheck.go
@@ -9,7 +9,6 @@ import (
 	"cmd/internal/objabi"
 	"cmd/link/internal/loader"
 	"fmt"
-	"internal/buildcfg"
 	"sort"
 	"strings"
 )
@@ -62,10 +61,6 @@ func (ctxt *Link) doStackCheck() {
 	// that there are at least StackLimit bytes available below SP
 	// when morestack returns.
 	limit := objabi.StackNosplit(*flagRace) - sc.callSize
-	if buildcfg.GOARCH == "arm64" {
-		// Need an extra 8 bytes below SP to save FP.
-		limit -= 8
-	}
 
 	// Compute stack heights without any back-tracking information.
 	// This will almost certainly succeed and we can simply
diff --git a/src/cmd/link/internal/x86/obj.go b/src/cmd/link/internal/x86/obj.go
index 4336f01ea3d536..a4885fde8fd06f 100644
--- a/src/cmd/link/internal/x86/obj.go
+++ b/src/cmd/link/internal/x86/obj.go
@@ -50,13 +50,14 @@ func Init() (*sys.Arch, ld.Arch) {
 
 		Plan9Magic: uint32(4*11*11 + 7),
 
-		Adddynrel:        adddynrel,
-		Archinit:         archinit,
-		Archreloc:        archreloc,
-		Archrelocvariant: archrelocvariant,
-		Gentext:          gentext,
-		Machoreloc1:      machoreloc1,
-		PEreloc1:         pereloc1,
+		Adddynrel:                 adddynrel,
+		Archinit:                  archinit,
+		Archreloc:                 archreloc,
+		Archrelocvariant:          archrelocvariant,
+		Gentext:                   gentext,
+		Machoreloc1:               machoreloc1,
+		PEreloc1:                  pereloc1,
+		ReturnAddressAtTopOfFrame: true,
 
 		ELF: ld.ELFArch{
 			Linuxdynld:     "/lib/ld-linux.so.2",
diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index a0e82ec830f74b..aa49a27a75d1e3 100644
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -50,9 +50,7 @@ TEXT _rt0_arm64_lib(SB),NOSPLIT,$184
 	CBZ	R4, nocgo
 	MOVD	$_rt0_arm64_lib_go(SB), R0
 	MOVD	$0, R1
-	SUB	$16, RSP		// reserve 16 bytes for sp-8 where fp may be saved.
 	BL	(R4)
-	ADD	$16, RSP
 	B	restore
 
 nocgo:
@@ -371,7 +369,6 @@ switch:
 	BL	runtime·save_g(SB)
 	MOVD	(g_sched+gobuf_sp)(g), R0
 	MOVD	R0, RSP
-	MOVD	(g_sched+gobuf_bp)(g), R29
 	MOVD	$0, (g_sched+gobuf_sp)(g)
 	MOVD	$0, (g_sched+gobuf_bp)(g)
 	RET
@@ -381,8 +378,8 @@ noswitch:
 	// Using a tail call here cleans up tracebacks since we won't stop
 	// at an intermediate systemstack.
 	MOVD	0(R26), R3	// code pointer
-	MOVD.P	16(RSP), R30	// restore LR
-	SUB	$8, RSP, R29	// restore FP
+	ADD	$16, RSP
+	LDP.P	16(RSP), (R29,R30)	// restore FP, LR
 	B	(R3)
 
 // func switchToCrashStack0(fn func())
@@ -1051,7 +1048,7 @@ again:
 // Smashes R0.
 TEXT gosave_systemstack_switch<>(SB),NOSPLIT|NOFRAME,$0
 	MOVD	$runtime·systemstack_switch(SB), R0
-	ADD	$8, R0	// get past prologue
+	ADD	$12, R0	// get past prologue
 	MOVD	R0, (g_sched+gobuf_pc)(g)
 	MOVD	RSP, R0
 	MOVD	R0, (g_sched+gobuf_sp)(g)
@@ -1069,9 +1066,7 @@ TEXT gosave_systemstack_switch<>(SB),NOSPLIT|NOFRAME,$0
 TEXT ·asmcgocall_no_g(SB),NOSPLIT,$0-16
 	MOVD	fn+0(FP), R1
 	MOVD	arg+8(FP), R0
-	SUB	$16, RSP	// skip over saved frame pointer below RSP
 	BL	(R1)
-	ADD	$16, RSP	// skip over saved frame pointer below RSP
 	RET
 
 // func asmcgocall(fn, arg unsafe.Pointer) int32
@@ -1236,9 +1231,9 @@ havem:
 	BL	runtime·save_g(SB)
 	MOVD	(g_sched+gobuf_sp)(g), R4 // prepare stack as R4
 	MOVD	(g_sched+gobuf_pc)(g), R5
-	MOVD	R5, -48(R4)
+	MOVD	R5, -8(R4)
 	MOVD	(g_sched+gobuf_bp)(g), R5
-	MOVD	R5, -56(R4)
+	MOVD	R5, -16(R4)
 	// Gather our arguments into registers.
 	MOVD	fn+0(FP), R1
 	MOVD	frame+8(FP), R2
@@ -1252,7 +1247,7 @@ havem:
 	CALL	(R0) // indirect call to bypass nosplit check. We're on a different stack now.
 
 	// Restore g->sched (== m->curg->sched) from saved values.
-	MOVD	0(RSP), R5
+	MOVD	40(RSP), R5
 	MOVD	R5, (g_sched+gobuf_pc)(g)
 	MOVD	RSP, R4
 	ADD	$48, R4, R4
@@ -1490,10 +1485,57 @@ GLOBL	debugCallFrameTooLarge<>(SB), RODATA, $20	// Size duplicated below
 //
 // This is ABIInternal because Go code injects its PC directly into new
 // goroutine stacks.
+//
+// State before debugger starts doing anything:
+// |   current   |
+// |   stack     |
+// +-------------+ <- SP = origSP
+// stopped executing at PC = origPC
+// some values are in LR (origLR) and FP (origFP)
+//
+// After debugger has done steps 1-6 above:
+// |   current   |
+// |   stack     |
+// +-------------+ <- origSP
+// |    -----    | (used to be a slot to store frame pointer on entry to origPC's frame.)
+// +-------------+
+// |   origLR    |
+// +-------------+ <- SP
+// |    -----    |
+// +-------------+
+// |   argsize   |
+// +-------------+
+// LR = origPC, PC = debugCallV2
+//
+// debugCallV2 then modifies the stack up to the "good" label:
+// |   current   |
+// |   stack     |
+// +-------------+ <- origSP
+// |    -----    | (used to be a slot to store frame pointer on entry to origPC's frame.)
+// +-------------+
+// |   origLR    |
+// +-------------+ <- where debugger left SP
+// |   origPC    |
+// +-------------+
+// |   origFP    |
+// +-------------+ <- FP = SP + 256
+// |   saved     |
+// |  registers  |
+// | (224 bytes) |
+// +-------------+ <- SP + 32
+// |  space for  |
+// |   outargs   |
+// +-------------+ <- SP + 8
+// |   argsize   |
+// +-------------+ <- SP
+
 TEXT runtime·debugCallV2(SB),NOSPLIT|NOFRAME,$0-0
-	STP	(R29, R30), -280(RSP)
-	SUB	$272, RSP, RSP
-	SUB	$8, RSP, R29
+	MOVD	R30, -8(RSP)		// save origPC
+	MOVD	-16(RSP), R30 		// save argsize in R30 temporarily
+	MOVD.W	R29, -16(RSP)		// push origFP
+	MOVD	RSP, R29		// frame pointer chain now set up
+	SUB	$256, RSP, RSP		// allocate frame
+	MOVD	R30, (RSP)		// Save argsize on the stack
 	// Save all registers that may contain pointers so they can be
 	// conservatively scanned.
 	//
@@ -1515,7 +1557,8 @@ TEXT runtime·debugCallV2(SB),NOSPLIT|NOFRAME,$0-0
 	STP	(R0, R1), (4*8)(RSP)
 
 	// Perform a safe-point check.
-	MOVD	R30, 8(RSP) // Caller's PC
+	MOVD	264(RSP), R0 // origPC
+	MOVD	R0, 8(RSP)
 	CALL	runtime·debugCallCheck(SB)
 	MOVD	16(RSP), R0
 	CBZ	R0, good
@@ -1559,7 +1602,7 @@ good:
 	CALL	runtime·debugCallWrap(SB);	\
 	JMP	restore
 
-	MOVD	256(RSP), R0 // the argument frame size
+	MOVD	(RSP), R0 // the argument frame size
 	DEBUG_CALL_DISPATCH(debugCall32<>, 32)
 	DEBUG_CALL_DISPATCH(debugCall64<>, 64)
 	DEBUG_CALL_DISPATCH(debugCall128<>, 128)
@@ -1607,9 +1650,9 @@ restore:
 	LDP	(6*8)(RSP), (R2, R3)
 	LDP	(4*8)(RSP), (R0, R1)
 
-	LDP	-8(RSP), (R29, R27)
-	ADD	$288, RSP, RSP // Add 16 more bytes, see saveSigContext
-	MOVD	-16(RSP), R30 // restore old lr
+	MOVD	272(RSP), R30		// restore old lr (saved by (*sigctxt).pushCall)
+	LDP	256(RSP), (R29, R27)	// restore old fp, set up resumption address
+	ADD	$288, RSP, RSP		// Pop frame, LR+FP, and block pushed by (*sigctxt).pushCall
 	JMP	(R27)
 
 // runtime.debugCallCheck assumes that functions defined with the
diff --git a/src/runtime/mkpreempt.go b/src/runtime/mkpreempt.go
index 769c4ffc5c9eeb..9064cae039f00d 100644
--- a/src/runtime/mkpreempt.go
+++ b/src/runtime/mkpreempt.go
@@ -488,26 +488,18 @@ func genARM64(g *gen) {
 		l.stack += 8 // SP needs 16-byte alignment
 	}
 
-	// allocate frame, save PC of interrupted instruction (in LR)
-	p("MOVD R30, %d(RSP)", -l.stack)
+	// allocate frame, save PC (in R30), FP (in R29) of interrupted instruction
+	p("STP.W (R29, R30), -16(RSP)")
+	p("MOVD RSP, R29") // set up new frame pointer
 	p("SUB $%d, RSP", l.stack)
-	p("MOVD R29, -8(RSP)") // save frame pointer (only used on Linux)
-	p("SUB $8, RSP, R29")  // set up new frame pointer
-	// On iOS, save the LR again after decrementing SP. We run the
-	// signal handler on the G stack (as it doesn't support sigaltstack),
-	// so any writes below SP may be clobbered.
-	p("#ifdef GOOS_ios")
-	p("MOVD R30, (RSP)")
-	p("#endif")
 
 	l.save(g)
 	p("CALL ·asyncPreempt2(SB)")
 	l.restore(g)
 
-	p("MOVD %d(RSP), R30", l.stack) // sigctxt.pushCall has pushed LR (at interrupt) on stack, restore it
-	p("MOVD -8(RSP), R29")          // restore frame pointer
-	p("MOVD (RSP), R27")            // load PC to REGTMP
-	p("ADD $%d, RSP", l.stack+16)   // pop frame (including the space pushed by sigctxt.pushCall)
+	p("MOVD %d(RSP), R30", l.stack+16)    // sigctxt.pushCall has pushed LR (at interrupt) on stack, restore it
+	p("LDP %d(RSP), (R29, R27)", l.stack) // Restore frame pointer. Load PC into regtmp.
+	p("ADD $%d, RSP", l.stack+32)         // pop frame (including the space pushed by sigctxt.pushCall)
 	p("RET (R27)")
 }
 
diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index 8c91c9435abd18..04b3afe1682765 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -1379,10 +1379,10 @@ func recovery(gp *g) {
 		// the caller
 		gp.sched.bp = fp - 2*goarch.PtrSize
 	case goarch.IsArm64 != 0:
-		// on arm64, the architectural bp points one word higher
-		// than the sp. fp is totally useless to us here, because it
-		// only gets us to the caller's fp.
-		gp.sched.bp = sp - goarch.PtrSize
+		// on arm64, the first two words of the frame are caller's PC
+		// (the saved LR register) and the caller's BP.
+		// Coincidentally, the same as amd64.
+		gp.sched.bp = fp - 2*goarch.PtrSize
 	}
 	gogo(&gp.sched)
 }
diff --git a/src/runtime/preempt_arm64.s b/src/runtime/preempt_arm64.s
index 31ec9d940f76d4..f4248cac257550 100644
--- a/src/runtime/preempt_arm64.s
+++ b/src/runtime/preempt_arm64.s
@@ -4,13 +4,9 @@
 #include "textflag.h"
 
 TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
-	MOVD R30, -496(RSP)
+	STP.W (R29, R30), -16(RSP)
+	MOVD RSP, R29
 	SUB $496, RSP
-	MOVD R29, -8(RSP)
-	SUB $8, RSP, R29
-	#ifdef GOOS_ios
-	MOVD R30, (RSP)
-	#endif
 	STP (R0, R1), 8(RSP)
 	STP (R2, R3), 24(RSP)
 	STP (R4, R5), 40(RSP)
@@ -78,8 +74,7 @@ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
 	LDP 40(RSP), (R4, R5)
 	LDP 24(RSP), (R2, R3)
 	LDP 8(RSP), (R0, R1)
-	MOVD 496(RSP), R30
-	MOVD -8(RSP), R29
-	MOVD (RSP), R27
-	ADD $512, RSP
+	MOVD 512(RSP), R30
+	LDP 496(RSP), (R29, R27)
+	ADD $528, RSP
 	RET (R27)
diff --git a/src/runtime/race_arm64.s b/src/runtime/race_arm64.s
index 5df650105bb4d5..feaa328d4c0d8a 100644
--- a/src/runtime/race_arm64.s
+++ b/src/runtime/race_arm64.s
@@ -397,7 +397,7 @@ TEXT	racecallatomic<>(SB), NOSPLIT, $0
 	// R3 = addr of incoming arg list
 
 	// Trigger SIGSEGV early.
-	MOVD	40(RSP), R3	// 1st arg is addr. after two times BL, get it at 40(RSP)
+	MOVD	72(RSP), R3	// 1st arg is addr. after two small frames (32 bytes each), get it at 72(RSP)
 	MOVB	(R3), R13	// segv here if addr is bad
 	// Check that addr is within [arenastart, arenaend) or within [racedatastart, racedataend).
 	MOVD	runtime·racearenastart(SB), R10
@@ -417,10 +417,11 @@ racecallatomic_ok:
 	// Addr is within the good range, call the atomic function.
 	load_g
 	MOVD	g_racectx(g), R0	// goroutine context
-	MOVD	16(RSP), R1	// caller pc
+	MOVD	56(RSP), R1	// caller pc
 	MOVD	R9, R2	// pc
-	ADD	$40, RSP, R3
-	JMP	racecall<>(SB)	// does not return
+	ADD	$72, RSP, R3
+	BL	racecall<>(SB)
+	RET
 racecallatomic_ignore:
 	// Addr is outside the good range.
 	// Call __tsan_go_ignore_sync_begin to ignore synchronization during the atomic op.
@@ -435,9 +436,9 @@ racecallatomic_ignore:
 	// racecall will call LLVM race code which might clobber R28 (g)
 	load_g
 	MOVD	g_racectx(g), R0	// goroutine context
-	MOVD	16(RSP), R1	// caller pc
+	MOVD	56(RSP), R1	// caller pc
 	MOVD	R9, R2	// pc
-	ADD	$40, RSP, R3	// arguments
+	ADD	$72, RSP, R3	// arguments
 	BL	racecall<>(SB)
 	// Call __tsan_go_ignore_sync_end.
 	MOVD	$__tsan_go_ignore_sync_end(SB), R9
@@ -476,10 +477,6 @@ TEXT	racecall<>(SB), NOSPLIT|NOFRAME, $0-0
 	MOVD	(g_sched+gobuf_sp)(R11), R12
 	MOVD	R12, RSP
 call:
-	// Decrement SP past where the frame pointer is saved in the Go arm64
-	// ABI (one word below the stack pointer) so the race detector library
-	// code doesn't clobber it
-	SUB	$16, RSP
 	BL	R9
 	MOVD	R19, RSP
 	JMP	(R20)
diff --git a/src/runtime/signal_arm64.go b/src/runtime/signal_arm64.go
index af7d29f9de1d31..61dad507219caf 100644
--- a/src/runtime/signal_arm64.go
+++ b/src/runtime/signal_arm64.go
@@ -8,7 +8,6 @@ package runtime
 
 import (
 	"internal/abi"
-	"internal/goarch"
 	"internal/runtime/sys"
 	"unsafe"
 )
@@ -63,18 +62,11 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
 	// We arrange lr, and pc to pretend the panicking
 	// function calls sigpanic directly.
 	// Always save LR to stack so that panics in leaf
-	// functions are correctly handled. This smashes
-	// the stack frame but we're not going back there
-	// anyway.
+	// functions are correctly handled.
+	// This extra space is known to gentraceback.
 	sp := c.sp() - sys.StackAlign // needs only sizeof uint64, but must align the stack
 	c.set_sp(sp)
 	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.lr()
-	// Make sure a valid frame pointer is saved on the stack so that the
-	// frame pointer checks in adjustframe are happy, if they're enabled.
-	// Frame pointer unwinding won't visit the sigpanic frame, since
-	// sigpanic will save the same frame pointer before calling into a panic
-	// function.
-	*(*uint64)(unsafe.Pointer(uintptr(sp - goarch.PtrSize))) = c.r29()
 
 	pc := gp.sigpc
 
@@ -96,10 +88,6 @@ func (c *sigctxt) pushCall(targetPC, resumePC uintptr) {
 	sp := c.sp() - 16 // SP needs 16-byte alignment
 	c.set_sp(sp)
 	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.lr()
-	// Make sure a valid frame pointer is saved on the stack so that the
-	// frame pointer checks in adjustframe are happy, if they're enabled.
-	// This is not actually used for unwinding.
-	*(*uint64)(unsafe.Pointer(uintptr(sp - goarch.PtrSize))) = c.r29()
 	// Set up PC and LR to pretend the function being signaled
 	// calls targetPC at resumePC.
 	c.set_lr(uint64(resumePC))
diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index 55e97e77afa957..5eaceec6da14d5 100644
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -579,23 +579,27 @@ var ptrnames = []string{
 // |  args to callee  |
 // +------------------+ <- frame->sp
 //
-// (arm)
+// (arm64)
 // +------------------+
 // | args from caller |
 // +------------------+ <- frame->argp
-// | caller's retaddr |
+// |          |
+// +------------------+ <- frame->fp (aka caller's sp)
+// |  return address  |
 // +------------------+
-// |  caller's FP (*) | (*) on ARM64, if framepointer_enabled && varp > sp
+// |  caller's FP     |  (frame pointer always enabled: TODO)
 // +------------------+ <- frame->varp
 // |     locals       |
 // +------------------+
 // |  args to callee  |
 // +------------------+
-// |  return address  |
+// |          |
 // +------------------+ <- frame->sp
 //
 // varp > sp means that the function has a frame;
 // varp == sp means frameless function.
+//
+// Alignment padding, if needed, will be between "locals" and "args to callee".
 
 type adjustinfo struct {
 	old   stack
@@ -709,7 +713,8 @@ func adjustframe(frame *stkframe, adjinfo *adjustinfo) {
 	}
 
 	// Adjust saved frame pointer if there is one.
-	if (goarch.ArchFamily == goarch.AMD64 || goarch.ArchFamily == goarch.ARM64) && frame.argp-frame.varp == 2*goarch.PtrSize {
+	if goarch.ArchFamily == goarch.AMD64 && frame.argp-frame.varp == 2*goarch.PtrSize ||
+		goarch.ArchFamily == goarch.ARM64 && frame.argp-frame.varp == 3*goarch.PtrSize {
 		if stackDebug >= 3 {
 			print("      saved bp\n")
 		}
@@ -723,10 +728,7 @@ func adjustframe(frame *stkframe, adjinfo *adjustinfo) {
 				throw("bad frame pointer")
 			}
 		}
-		// On AMD64, this is the caller's frame pointer saved in the current
-		// frame.
-		// On ARM64, this is the frame pointer of the caller's caller saved
-		// by the caller in its frame (one word below its SP).
+		// This is the caller's frame pointer saved in the current frame.
 		adjustpointer(adjinfo, unsafe.Pointer(frame.varp))
 	}
 
diff --git a/src/runtime/testdata/testprog/badtraceback.go b/src/runtime/testdata/testprog/badtraceback.go
index 455118a54371d7..36575f765db9a5 100644
--- a/src/runtime/testdata/testprog/badtraceback.go
+++ b/src/runtime/testdata/testprog/badtraceback.go
@@ -41,6 +41,11 @@ func badLR2(arg int) {
 	if runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" {
 		lrOff = 32 // FIXED_FRAME or sys.MinFrameSize
 	}
+	if runtime.GOARCH == "arm64" {
+		// skip 8 bytes at bottom of parent frame, then point
+		// to the 8 bytes of the saved PC at the top of the frame.
+		lrOff = 16
+	}
 	lrPtr := (*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&arg)) - lrOff))
 	*lrPtr = 0xbad
 
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index 8882c306edb736..1c3e679a02bdaf 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -175,6 +175,11 @@ func (u *unwinder) initAt(pc0, sp0, lr0 uintptr, gp *g, flags unwindFlags) {
 	// Start in the caller's frame.
 	if frame.pc == 0 {
 		if usesLR {
+			// TODO: this isn't right on arm64. But also, this should
+			// ~never happen. Calling a nil function will panic
+			// when loading the PC out of the closure, not when
+			// branching to that PC. (Closures should always have
+			// valid PCs in their first word.)
 			frame.pc = *(*uintptr)(unsafe.Pointer(frame.sp))
 			frame.lr = 0
 		} else {
@@ -369,7 +374,11 @@ func (u *unwinder) resolveInternal(innermost, isSyscall bool) {
 		var lrPtr uintptr
 		if usesLR {
 			if innermost && frame.sp < frame.fp || frame.lr == 0 {
-				lrPtr = frame.sp
+				if GOARCH == "arm64" {
+					lrPtr = frame.fp - goarch.PtrSize
+				} else {
+					lrPtr = frame.sp
+				}
 				frame.lr = *(*uintptr)(unsafe.Pointer(lrPtr))
 			}
 		} else {
@@ -385,24 +394,17 @@ func (u *unwinder) resolveInternal(innermost, isSyscall bool) {
 		// On x86, call instruction pushes return PC before entering new function.
 		frame.varp -= goarch.PtrSize
 	}
+	if GOARCH == "arm64" && frame.varp > frame.sp {
+		frame.varp -= goarch.PtrSize // LR have been saved, skip over it.
+	}
 
 	// For architectures with frame pointers, if there's
 	// a frame, then there's a saved frame pointer here.
 	//
 	// NOTE: This code is not as general as it looks.
-	// On x86, the ABI is to save the frame pointer word at the
+	// On x86 and arm64, the ABI is to save the frame pointer word at the
 	// top of the stack frame, so we have to back down over it.
-	// On arm64, the frame pointer should be at the bottom of
-	// the stack (with R29 (aka FP) = RSP), in which case we would
-	// not want to do the subtraction here. But we started out without
-	// any frame pointer, and when we wanted to add it, we didn't
-	// want to break all the assembly doing direct writes to 8(RSP)
-	// to set the first parameter to a called function.
-	// So we decided to write the FP link *below* the stack pointer
-	// (with R29 = RSP - 8 in Go functions).
-	// This is technically ABI-compatible but not standard.
-	// And it happens to end up mimicking the x86 layout.
-	// Other architectures may make different decisions.
+	// No other architectures are framepointer-enabled at the moment.
 	if frame.varp > frame.sp && framepointer_enabled {
 		frame.varp -= goarch.PtrSize
 	}
@@ -562,7 +564,7 @@ func (u *unwinder) finishInternal() {
 	gp := u.g.ptr()
 	if u.flags&(unwindPrintErrors|unwindSilentErrors) == 0 && u.frame.sp != gp.stktopsp {
 		print("runtime: g", gp.goid, ": frame.sp=", hex(u.frame.sp), " top=", hex(gp.stktopsp), "\n")
-		print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "\n")
+		print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "]\n")
 		throw("traceback did not unwind completely")
 	}
 }
diff --git a/test/nosplit.go b/test/nosplit.go
index 4b4c93b1d067c5..1f943fa18c3f58 100644
--- a/test/nosplit.go
+++ b/test/nosplit.go
@@ -142,7 +142,7 @@ start 136
 # (CallSize is 32 on ppc64, 8 on amd64 for frame pointer.)
 start 96 nosplit
 start 100 nosplit; REJECT ppc64 ppc64le
-start 104 nosplit; REJECT ppc64 ppc64le arm64
+start 104 nosplit; REJECT ppc64 ppc64le
 start 108 nosplit; REJECT ppc64 ppc64le
 start 112 nosplit; REJECT ppc64 ppc64le arm64
 start 116 nosplit; REJECT ppc64 ppc64le
@@ -160,7 +160,7 @@ start 136 nosplit; REJECT
 # Because AMD64 uses frame pointer, it has 8 fewer bytes.
 start 96 nosplit call f; f 0 nosplit
 start 100 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le
-start 104 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le arm64
+start 104 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le
 start 108 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le
 start 112 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le amd64 arm64
 start 116 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le amd64
@@ -176,7 +176,7 @@ start 136 nosplit call f; f 0 nosplit; REJECT
 # Architectures differ in the same way as before.
 start 96 nosplit call f; f 0 call f
 start 100 nosplit call f; f 0 call f; REJECT ppc64 ppc64le
-start 104 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64 arm64
+start 104 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64
 start 108 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64
 start 112 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64 arm64
 start 116 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64
@@ -189,7 +189,7 @@ start 136 nosplit call f; f 0 call f; REJECT
 # Indirect calls are assumed to be splitting functions.
 start 96 nosplit callind
 start 100 nosplit callind; REJECT ppc64 ppc64le
-start 104 nosplit callind; REJECT ppc64 ppc64le amd64 arm64
+start 104 nosplit callind; REJECT ppc64 ppc64le amd64
 start 108 nosplit callind; REJECT ppc64 ppc64le amd64
 start 112 nosplit callind; REJECT ppc64 ppc64le amd64 arm64
 start 116 nosplit callind; REJECT ppc64 ppc64le amd64

From 4fca79833fcdd0dc19bb0feba8715a0def3d07be Mon Sep 17 00:00:00 2001
From: tony 
Date: Mon, 29 Sep 2025 14:25:57 +0000
Subject: [PATCH 067/229] runtime: delete redundant code in the page allocator

The page allocator's scavenge index has sysGrow called on it twice,
once in pageAlloc.grow, and once in pageAlloc.sysGrow on 64-bit
platforms. Calling it twice is OK since sysGrow is idempotent,
but it's also wasteful. This change removes the call
in pageAlloc.sysGrow.

Change-Id: I5b955b6e2beed5c2b8305ab82b76718ea305792c
Reviewed-on: https://go-review.googlesource.com/c/go/+/707735
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Knyszek 
Reviewed-by: Carlos Amedee 
---
 src/runtime/mpagealloc_64bit.go | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/src/runtime/mpagealloc_64bit.go b/src/runtime/mpagealloc_64bit.go
index eb425f070445dd..2e3643004bc858 100644
--- a/src/runtime/mpagealloc_64bit.go
+++ b/src/runtime/mpagealloc_64bit.go
@@ -180,9 +180,6 @@ func (p *pageAlloc) sysGrow(base, limit uintptr) {
 		sysUsed(unsafe.Pointer(need.base.addr()), need.size(), need.size())
 		p.summaryMappedReady += need.size()
 	}
-
-	// Update the scavenge index.
-	p.summaryMappedReady += p.scav.index.sysGrow(base, limit, p.sysStat)
 }
 
 // sysGrow increases the index's backing store in response to a heap growth.

From 1d62e92567a858b18f4e7e0c24e071c039dd3edf Mon Sep 17 00:00:00 2001
From: Cherry Mui 
Date: Sat, 4 Oct 2025 11:32:33 -0400
Subject: [PATCH 068/229] test/codegen: make sure assignment results are used.

Some tests make assignments to an argument without reading it.
With CL 708865, they are treated as dead stores and are removed.
Make sure the results are used.

Fixes #75745.
Fixes #75746.

Change-Id: I05580beb1006505ec1550e5fa245b54dcefd10b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/708916
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
---
 test/codegen/constants.go | 6 ++++--
 test/codegen/mathbits.go  | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/test/codegen/constants.go b/test/codegen/constants.go
index 3ce17d0ad3a65b..0935a9e53a9d87 100644
--- a/test/codegen/constants.go
+++ b/test/codegen/constants.go
@@ -7,7 +7,7 @@
 package codegen
 
 // A uint16 or sint16 constant shifted left.
-func shifted16BitConstants(out [64]uint64) {
+func shifted16BitConstants() (out [64]uint64) {
 	// ppc64x: "MOVD\t[$]8193,", "SLD\t[$]27,"
 	out[0] = 0x0000010008000000
 	// ppc64x: "MOVD\t[$]-32767", "SLD\t[$]26,"
@@ -16,10 +16,11 @@ func shifted16BitConstants(out [64]uint64) {
 	out[2] = 0xFFFF000000000000
 	// ppc64x: "MOVD\t[$]65535", "SLD\t[$]44,"
 	out[3] = 0x0FFFF00000000000
+	return
 }
 
 // A contiguous set of 1 bits, potentially wrapping.
-func contiguousMaskConstants(out [64]uint64) {
+func contiguousMaskConstants() (out [64]uint64) {
 	// ppc64x: "MOVD\t[$]-1", "RLDC\tR[0-9]+, [$]44, [$]63,"
 	out[0] = 0xFFFFF00000000001
 	// ppc64x: "MOVD\t[$]-1", "RLDC\tR[0-9]+, [$]43, [$]63,"
@@ -30,4 +31,5 @@ func contiguousMaskConstants(out [64]uint64) {
 	// ppc64x/power9: "MOVD\t[$]-1", "RLDC\tR[0-9]+, [$]33, [$]63,"
 	// ppc64x/power10: "MOVD\t[$]-8589934591,"
 	out[3] = 0xFFFFFFFE00000001
+	return
 }
diff --git a/test/codegen/mathbits.go b/test/codegen/mathbits.go
index ba5387d2c32121..f8fa374c0af483 100644
--- a/test/codegen/mathbits.go
+++ b/test/codegen/mathbits.go
@@ -731,7 +731,7 @@ func Add64MPanicOnOverflowGT(a, b [2]uint64) [2]uint64 {
 //
 // This is what happened on PPC64 when compiling
 // crypto/internal/edwards25519/field.feMulGeneric.
-func Add64MultipleChains(a, b, c, d [2]uint64) {
+func Add64MultipleChains(a, b, c, d [2]uint64) [2]uint64 {
 	var cx, d1, d2 uint64
 	a1, a2 := a[0], a[1]
 	b1, b2 := b[0], b[1]
@@ -748,6 +748,7 @@ func Add64MultipleChains(a, b, c, d [2]uint64) {
 	d2, _ = bits.Add64(c2, d2, cx)
 	d[0] = d1
 	d[1] = d2
+	return d
 }
 
 // --------------- //

From 7bfeb43509acbe75ce8e1a14c60bffe597e46813 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 19:16:36 -0400
Subject: [PATCH 069/229] cmd/go: refactor usage of `initialized`

This commit refactors usage of the global variable `initialized` to
the global LoaderState field of the same name.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf 'ex { initialized -> LoaderState.initialized }'
rf 'rm initialized'

Change-Id: I97e35bab00f4c22661670b01b69425fc25efe6df
Reviewed-on: https://go-review.googlesource.com/c/go/+/698056
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modload/init.go | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 5192fe0fc8cc58..d7d532ec942665 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -60,7 +60,6 @@ var (
 
 // Variables set in Init.
 var (
-	initialized bool
 
 	// These are primarily used to initialize the MainModules, and should be
 	// eventually superseded by them but are still used in cases where the module
@@ -406,7 +405,7 @@ func Reset() {
 
 func setState(s State) State {
 	oldState := State{
-		initialized:     initialized,
+		initialized:     LoaderState.initialized,
 		forceUseModules: ForceUseModules,
 		rootMode:        RootMode,
 		modRoots:        modRoots,
@@ -414,7 +413,7 @@ func setState(s State) State {
 		mainModules:     MainModules,
 		requirements:    requirements,
 	}
-	initialized = s.initialized
+	LoaderState.initialized = s.initialized
 	ForceUseModules = s.forceUseModules
 	RootMode = s.rootMode
 	modRoots = s.modRoots
@@ -450,10 +449,10 @@ var LoaderState = NewState()
 // configures the cfg, codehost, load, modfetch, and search packages for use
 // with modules.
 func Init() {
-	if initialized {
+	if LoaderState.initialized {
 		return
 	}
-	initialized = true
+	LoaderState.initialized = true
 
 	fips140.Init()
 
@@ -573,7 +572,7 @@ func WillBeEnabled() bool {
 		// Already enabled.
 		return true
 	}
-	if initialized {
+	if LoaderState.initialized {
 		// Initialized, not enabled.
 		return false
 	}
@@ -640,7 +639,7 @@ func VendorDir() string {
 }
 
 func inWorkspaceMode() bool {
-	if !initialized {
+	if !LoaderState.initialized {
 		panic("inWorkspaceMode called before modload.Init called")
 	}
 	if !Enabled() {
@@ -1253,7 +1252,7 @@ func fixVersion(ctx context.Context, fixed *bool) modfile.VersionFixer {
 // This function affects the default cfg.BuildMod when outside of a module,
 // so it can only be called prior to Init.
 func AllowMissingModuleImports() {
-	if initialized {
+	if LoaderState.initialized {
 		panic("AllowMissingModuleImports after Init")
 	}
 	allowMissingModuleImports = true

From 7fbf54bfebf9243550177bc6871d80e58bedf1a6 Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Sun, 9 Mar 2025 17:19:48 +0000
Subject: [PATCH 070/229] internal/buildcfg: enable greenteagc experiment by
 default

Slightly bump the value in Test/wasmmemsize.go. We use 1 additional page
compared to before, and we were already sitting *right* on the edge.

For #73581.

Change-Id: I485df16c3cf59803a8a1fc852b3e90666981ab09
Reviewed-on: https://go-review.googlesource.com/c/go/+/656195
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Michael Knyszek 
Reviewed-by: Cherry Mui 
---
 src/internal/buildcfg/exp.go |  6 ++++++
 test/wasmmemsize.dir/main.go | 12 +++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/internal/buildcfg/exp.go b/src/internal/buildcfg/exp.go
index d06913d9a7f25a..fb6b5859e31a1e 100644
--- a/src/internal/buildcfg/exp.go
+++ b/src/internal/buildcfg/exp.go
@@ -78,12 +78,18 @@ func ParseGOEXPERIMENT(goos, goarch, goexp string) (*ExperimentFlags, error) {
 	// things like .debug_addr (needed for DWARF 5).
 	dwarf5Supported := (goos != "darwin" && goos != "ios" && goos != "aix")
 
+	// The compiler crashes while compiling some of the Green Tea code.
+	// The Green Tea code is pretty normal, so this is likely a compiler
+	// bug in the loong64 port.
+	greenTeaGCSupported := goarch != "loong64"
+
 	baseline := goexperiment.Flags{
 		RegabiWrappers:        regabiSupported,
 		RegabiArgs:            regabiSupported,
 		Dwarf5:                dwarf5Supported,
 		RandomizedHeapBase64:  true,
 		SizeSpecializedMalloc: true,
+		GreenTeaGC:            greenTeaGCSupported,
 	}
 
 	// Start with the statically enabled set of experiments.
diff --git a/test/wasmmemsize.dir/main.go b/test/wasmmemsize.dir/main.go
index e3aa5b5e92154c..c51e6b3b0476c9 100644
--- a/test/wasmmemsize.dir/main.go
+++ b/test/wasmmemsize.dir/main.go
@@ -9,17 +9,19 @@ import (
 	"io"
 )
 
-// Expect less than 3 MB of memory usage for a small wasm program.
-// This reflects the current allocator. If the allocator changes,
-// update this value.
-const want = 3 << 20
+// Wasm page size.
+const pageSize = 64 * 1024
+
+// Expect less than 3 MB + 1 page of memory usage for a small wasm
+// program. This reflects the current allocator. If the allocator
+// changes, update this value.
+const want = 3<<20 + pageSize
 
 var w = io.Discard
 
 func main() {
 	fmt.Fprintln(w, "hello world")
 
-	const pageSize = 64 * 1024
 	sz := uintptr(currentMemory()) * pageSize
 	if sz > want {
 		fmt.Printf("FAIL: unexpected memory size %d, want <= %d\n", sz, want)

From c1e6e49d5d3f3fb927f1bfd1b453d8e7c906c6ac Mon Sep 17 00:00:00 2001
From: thepudds 
Date: Fri, 3 Oct 2025 10:59:54 -0400
Subject: [PATCH 071/229] fmt: reduce Errorf("x") allocations to match
 errors.New("x")
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

For unformatted strings, it comes up periodically that there are
more allocations using fmt.Errorf("x") compared to errors.New("x").
People cite it as a reason to switch code using fmt.Errorf to
use errors.New instead.

Three examples from the last few weeks essentially made
this suggestion: #75235, CL 708496, and CL 708618. Prior to that,
it is periodically suggested as a vet check (e.g., proposals #17173
and #52696) or in various CLs to change the standard library
(e.g., CL 403938 and CL 588776).

On the other hand, I believe the position of the core Go team
is that it is usually not worthwhile to make such a change. For example,
in #52696, Russ wrote:

  Thanks for raising the issue, but please don't do this. Using
  fmt.Errorf("foo") is completely fine, especially in a program where
  all the errors are constructed with fmt.Errorf. Having to
  mentally switch between two functions based on the argument
  is unnecessary noise.

This CL attempts to mostly take performance out of the discussion.

We drop from 2 allocations to 0 allocations for a non-escaping error,
and drop from 2 allocations to 1 allocation for an escaping error:

  _ = fmt.Errorf("foo")    // non-escaping error
  sink = fmt.Errorf("foo") // escaping error

This now matches the allocations for errors.New("foo") in both cases.

The CPU cost difference is greatly reduced, though there is still
a small ~4ns difference measurable in these microbenchmarks. Previously,
it was ~64ns vs. ~21ns for fmt.Errorf("x") vs. errors.New("x")
for escaping errors, whereas with this CL it is now ~25ns vs. ~21ns.

When fmt.Errorf("foo") executes with this CL, there are essentially
three optimizations now, in rough order of usefulness:
 (1) we always avoid an allocation inside the doPrintf machinery;
 (2) if the error does not otherwise escape, we can stack allocate
     the errors.errorString struct by virtue of mid-stack inlining
     of fmt.Errorf and the resulting inlining of errors.New, which
     also can be more effective via PGO;
 (3) stringslite.IndexByte is a tiny bit faster than going through the
     for loops looking for '%' inside doPrintf.

See https://blog.filippo.io/efficient-go-apis-with-the-inliner/ for
background on avoiding heap allocations via mid-stack inlining.

The common case here is likely that the string format argument is a
constant when there are no other arguments.

However, one concern could be that by not allocating a copy, we could
now keep a string argument alive longer with this change, which could
be a pessimization if for example that string argument is a
slice of a much bigger string:

  s := bigString[m:n]
  longLivedErr := fmt.Errorf(s)

Aside from that being perhaps unusual code, vet will complain about
s there as a "non-constant format string in call to fmt.Errorf", so that
particular example seems unlikely to occur frequently in practice.

The main benchmark results are below. "old" is prior to this CL, "new"
is with this CL. The non-escaping case is "local", the escaping case is
"sink". In practice, I suspect errors escape the majority of the time.
Benchmark code at https://go.dev/play/p/rlRSO1ehx8O

goos: linux
goarch: amd64
pkg: fmt
cpu: AMD EPYC 7B13
                         │  old-7bd6fac4.txt      │           new-dcd2a72f0.txt    │
                         │      sec/op            │   sec/op     vs base           │
Errorf/no-args/local-16              63.76n ± 1%   4.874n ± 0%  -92.36% (n=120)
Errorf/no-args/sink-16               64.25n ± 1%   25.81n ± 0%  -59.83% (n=120)
Errorf/int-arg/local-16              90.86n ± 1%   90.97n ± 1%        ~ (p=0.713 n=120)
Errorf/int-arg/sink-16               91.81n ± 1%   91.10n ± 1%   -0.76% (p=0.036 n=120)
geomean                              76.46n        31.95n       -58.20%

                         │  old-7bd6fac4.txt      │             new-dcd2a72f0.txt  │
                         │       B/op             │    B/op     vs base            │
Errorf/no-args/local-16               19.00 ± 0%    0.00 ± 0%  -100.00% (n=120)
Errorf/no-args/sink-16                19.00 ± 0%   16.00 ± 0%   -15.79% (n=120)
Errorf/int-arg/local-16               24.00 ± 0%   24.00 ± 0%         ~ (p=1.000 n=120) ¹
Errorf/int-arg/sink-16                24.00 ± 0%   24.00 ± 0%         ~ (p=1.000 n=120) ¹
geomean                               21.35                    ?                        ² ³
¹ all samples are equal

                         │  old-7bd6fac4.txt      │       new-dcd2a72f0.txt        │
                         │     allocs/op          │ allocs/op   vs base            │
Errorf/no-args/local-16               2.000 ± 0%   0.000 ± 0%  -100.00% (n=120)
Errorf/no-args/sink-16                2.000 ± 0%   1.000 ± 0%   -50.00% (n=120)
Errorf/int-arg/local-16               2.000 ± 0%   2.000 ± 0%         ~ (p=1.000 n=120) ¹
Errorf/int-arg/sink-16                2.000 ± 0%   2.000 ± 0%         ~ (p=1.000 n=120) ¹
geomean                               2.000                    ?                        ² ³
¹ all samples are equal

Change-Id: Ib27c52933bec5c2236624c577fbb1741052e792f
Reviewed-on: https://go-review.googlesource.com/c/go/+/708836
Reviewed-by: Damien Neil 
LUCI-TryBot-Result: Go LUCI 
Commit-Queue: t hepudds 
Reviewed-by: Alan Donovan 
Reviewed-by: Emmanuel Odeke 
---
 src/fmt/errors.go      | 18 +++++++++++++++++-
 src/fmt/errors_test.go |  9 +++++++++
 src/fmt/fmt_test.go    |  5 +++++
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/fmt/errors.go b/src/fmt/errors.go
index 1ac83404bc7c55..a0ce7ada346dbc 100644
--- a/src/fmt/errors.go
+++ b/src/fmt/errors.go
@@ -6,6 +6,7 @@ package fmt
 
 import (
 	"errors"
+	"internal/stringslite"
 	"slices"
 )
 
@@ -19,7 +20,22 @@ import (
 // order they appear in the arguments.
 // It is invalid to supply the %w verb with an operand that does not implement
 // the error interface. The %w verb is otherwise a synonym for %v.
-func Errorf(format string, a ...any) error {
+func Errorf(format string, a ...any) (err error) {
+	// This function has been split in a somewhat unnatural way
+	// so that both it and the errors.New call can be inlined.
+	if err = errorf(format, a...); err != nil {
+		return err
+	}
+	// No formatting was needed. We can avoid some allocations and other work.
+	// See https://go.dev/cl/708836 for details.
+	return errors.New(format)
+}
+
+// errorf formats and returns an error value, or nil if no formatting is required.
+func errorf(format string, a ...any) error {
+	if len(a) == 0 && stringslite.IndexByte(format, '%') == -1 {
+		return nil
+	}
 	p := newPrinter()
 	p.wrapErrs = true
 	p.doPrintf(format, a)
diff --git a/src/fmt/errors_test.go b/src/fmt/errors_test.go
index 4eb55faffe7a18..52bf42d0a623a6 100644
--- a/src/fmt/errors_test.go
+++ b/src/fmt/errors_test.go
@@ -54,6 +54,15 @@ func TestErrorf(t *testing.T) {
 	}, {
 		err:      noVetErrorf("%w is not an error", "not-an-error"),
 		wantText: "%!w(string=not-an-error) is not an error",
+	}, {
+		err:      fmt.Errorf("no verbs"),
+		wantText: "no verbs",
+	}, {
+		err:      noVetErrorf("no verbs with extra arg", "extra"),
+		wantText: "no verbs with extra arg%!(EXTRA string=extra)",
+	}, {
+		err:      noVetErrorf("too many verbs: %w %v"),
+		wantText: "too many verbs: %!w(MISSING) %!v(MISSING)",
 	}, {
 		err:       noVetErrorf("wrapped two errors: %w %w", errString("1"), errString("2")),
 		wantText:  "wrapped two errors: 1 2",
diff --git a/src/fmt/fmt_test.go b/src/fmt/fmt_test.go
index 86e458ae6481fb..c07da5683c2463 100644
--- a/src/fmt/fmt_test.go
+++ b/src/fmt/fmt_test.go
@@ -1480,6 +1480,7 @@ func BenchmarkFprintIntNoAlloc(b *testing.B) {
 
 var mallocBuf bytes.Buffer
 var mallocPointer *int // A pointer so we know the interface value won't allocate.
+var sink any
 
 var mallocTest = []struct {
 	count int
@@ -1510,6 +1511,10 @@ var mallocTest = []struct {
 		mallocBuf.Reset()
 		Fprintf(&mallocBuf, "%x %x %x", mallocPointer, mallocPointer, mallocPointer)
 	}},
+	{0, `Errorf("hello")`, func() { _ = Errorf("hello") }},
+	{2, `Errorf("hello: %x")`, func() { _ = Errorf("hello: %x", mallocPointer) }},
+	{1, `sink = Errorf("hello")`, func() { sink = Errorf("hello") }},
+	{2, `sink = Errorf("hello: %x")`, func() { sink = Errorf("hello: %x", mallocPointer) }},
 }
 
 var _ bytes.Buffer

From 4c0fd3a2b45675a581ef6fa273a221d7131b5647 Mon Sep 17 00:00:00 2001
From: Mateusz Poliwczak 
Date: Mon, 6 Oct 2025 20:54:27 +0200
Subject: [PATCH 072/229] internal/goexperiment: remove the synctest
 GOEXPERIMENT

synctest package is enabled by default and the synctest
goexperiment does nothing after CL 709355.

Change-Id: Ia96b070d5f3779ae7c38a9044f754e716a6a6964
Reviewed-on: https://go-review.googlesource.com/c/go/+/709555
Reviewed-by: Michael Pratt 
Reviewed-by: Damien Neil 
LUCI-TryBot-Result: Go LUCI 
---
 src/internal/goexperiment/exp_synctest_off.go | 8 --------
 src/internal/goexperiment/exp_synctest_on.go  | 8 --------
 src/internal/goexperiment/flags.go            | 3 ---
 3 files changed, 19 deletions(-)
 delete mode 100644 src/internal/goexperiment/exp_synctest_off.go
 delete mode 100644 src/internal/goexperiment/exp_synctest_on.go

diff --git a/src/internal/goexperiment/exp_synctest_off.go b/src/internal/goexperiment/exp_synctest_off.go
deleted file mode 100644
index fade13f89ca79c..00000000000000
--- a/src/internal/goexperiment/exp_synctest_off.go
+++ /dev/null
@@ -1,8 +0,0 @@
-// Code generated by mkconsts.go. DO NOT EDIT.
-
-//go:build !goexperiment.synctest
-
-package goexperiment
-
-const Synctest = false
-const SynctestInt = 0
diff --git a/src/internal/goexperiment/exp_synctest_on.go b/src/internal/goexperiment/exp_synctest_on.go
deleted file mode 100644
index 9c44be7276138b..00000000000000
--- a/src/internal/goexperiment/exp_synctest_on.go
+++ /dev/null
@@ -1,8 +0,0 @@
-// Code generated by mkconsts.go. DO NOT EDIT.
-
-//go:build goexperiment.synctest
-
-package goexperiment
-
-const Synctest = true
-const SynctestInt = 1
diff --git a/src/internal/goexperiment/flags.go b/src/internal/goexperiment/flags.go
index 232a17135d2cc5..07aa1d0aeed15d 100644
--- a/src/internal/goexperiment/flags.go
+++ b/src/internal/goexperiment/flags.go
@@ -100,9 +100,6 @@ type Flags struct {
 	// inlining phase within the Go compiler.
 	NewInliner bool
 
-	// Synctest enables the testing/synctest package.
-	Synctest bool
-
 	// Dwarf5 enables DWARF version 5 debug info generation.
 	Dwarf5 bool
 

From 64699542031b994ec4fdb6de887a94b69a372f9b Mon Sep 17 00:00:00 2001
From: Michael Pratt 
Date: Mon, 6 Oct 2025 16:38:29 -0400
Subject: [PATCH 073/229] runtime: assert p.destroy runs with GC not running

This is already guaranteed by stopTheWorldGC prior to procresize. Thus
the cleanup code here is dead, which is a bit confusing.

Replace it with a throw for clarity.

Change-Id: I6a6a636c8ca1487b720c4fab41b2b86c13d1d9e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/709655
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Knyszek 
---
 src/runtime/proc.go | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index e5686705293e8a..d36895b046c8c6 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -5818,11 +5818,13 @@ func (pp *p) destroy() {
 	// Move all timers to the local P.
 	getg().m.p.ptr().timers.take(&pp.timers)
 
-	// Flush p's write barrier buffer.
-	if gcphase != _GCoff {
-		wbBufFlush1(pp)
-		pp.gcw.dispose()
+	// No need to flush p's write barrier buffer or span queue, as Ps
+	// cannot be destroyed during the mark phase.
+	if phase := gcphase; phase != _GCoff {
+		println("runtime: p id", pp.id, "destroyed during GC phase", phase)
+		throw("P destroyed while GC is running")
 	}
+
 	clear(pp.sudogbuf[:])
 	pp.sudogcache = pp.sudogbuf[:0]
 	pp.pinnerCache = nil

From c938051dd0b80a5c60572d6807270d06ca685d2e Mon Sep 17 00:00:00 2001
From: Keith Randall 
Date: Tue, 7 Oct 2025 07:58:50 -0700
Subject: [PATCH 074/229] Revert "cmd/compile: redo arm64 LR/FP save and
 restore"

This reverts commit 719dfcf8a8478d70360bf3c34c0e920be7b32994.

Reason for revert: Causing crashes.

Change-Id: I0b8526dd03d82fa074ce4f97f1789eeac702b3eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/709755
Reviewed-by: Keith Randall 
Reviewed-by: David Chase 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Keith Randall 
Reviewed-by: Cherry Mui 
---
 src/cmd/compile/abi-internal.md               |  12 +-
 src/cmd/compile/internal/arm64/ggen.go        |  10 +-
 src/cmd/compile/internal/arm64/ssa.go         |   2 +-
 src/cmd/compile/internal/ssagen/pgen.go       |   6 -
 src/cmd/compile/internal/ssagen/ssa.go        |   3 +-
 src/cmd/internal/obj/arm64/asm7.go            |  12 +-
 src/cmd/internal/obj/arm64/obj7.go            | 326 ++++++++++++------
 src/cmd/link/internal/amd64/obj.go            |  19 +-
 src/cmd/link/internal/arm64/obj.go            |  23 +-
 src/cmd/link/internal/ld/dwarf.go             |   7 +-
 src/cmd/link/internal/ld/lib.go               |   4 -
 src/cmd/link/internal/ld/stackcheck.go        |   5 +
 src/cmd/link/internal/x86/obj.go              |  15 +-
 src/runtime/asm_arm64.s                       |  81 +----
 src/runtime/mkpreempt.go                      |  20 +-
 src/runtime/panic.go                          |   8 +-
 src/runtime/preempt_arm64.s                   |  15 +-
 src/runtime/race_arm64.s                      |  17 +-
 src/runtime/signal_arm64.go                   |  16 +-
 src/runtime/stack.go                          |  20 +-
 src/runtime/testdata/testprog/badtraceback.go |   5 -
 src/runtime/traceback.go                      |  30 +-
 test/nosplit.go                               |   8 +-
 23 files changed, 361 insertions(+), 303 deletions(-)

diff --git a/src/cmd/compile/abi-internal.md b/src/cmd/compile/abi-internal.md
index 490e1affb74de9..eae230dc070d86 100644
--- a/src/cmd/compile/abi-internal.md
+++ b/src/cmd/compile/abi-internal.md
@@ -576,19 +576,19 @@ A function's stack frame, after the frame is created, is laid out as
 follows:
 
     +------------------------------+
-    | return PC                    |
-    | frame pointer on entry       | ← R29 points to
     | ... locals ...               |
     | ... outgoing arguments ...   |
-    | unused word                  | ← RSP points to
+    | return PC                    | ← RSP points to
+    | frame pointer on entry       |
     +------------------------------+ ↓ lower addresses
 
 The "return PC" is loaded to the link register, R30, as part of the
 arm64 `CALL` operation.
 
-On entry, a function pushes R30 (the return address) and R29
-(the caller's frame pointer) onto the bottom of the stack. It then
-subtracts a constant from RSP to open its stack frame.
+On entry, a function subtracts from RSP to open its stack frame, and
+saves the values of R30 and R29 at the bottom of the frame.
+Specifically, R30 is saved at 0(RSP) and R29 is saved at -8(RSP),
+after RSP is updated.
 
 A leaf function that does not require any stack space may omit the
 saved R30 and R29.
diff --git a/src/cmd/compile/internal/arm64/ggen.go b/src/cmd/compile/internal/arm64/ggen.go
index 6ba56b992eeda6..14027467002a3e 100644
--- a/src/cmd/compile/internal/arm64/ggen.go
+++ b/src/cmd/compile/internal/arm64/ggen.go
@@ -11,12 +11,10 @@ import (
 )
 
 func padframe(frame int64) int64 {
-	// arm64 requires frame sizes here that are 8 mod 16.
-	// With the additional (unused) slot at the bottom of the frame,
-	// that makes an aligned 16 byte frame.
-	// Adding a save region for LR+FP does not change the alignment.
-	if frame != 0 {
-		frame += (-(frame + 8)) & 15
+	// arm64 requires that the frame size (not counting saved FP&LR)
+	// be 16 bytes aligned. If not, pad it.
+	if frame%16 != 0 {
+		frame += 16 - (frame % 16)
 	}
 	return frame
 }
diff --git a/src/cmd/compile/internal/arm64/ssa.go b/src/cmd/compile/internal/arm64/ssa.go
index 9f79a740c6ca81..7bc0e536e941e6 100644
--- a/src/cmd/compile/internal/arm64/ssa.go
+++ b/src/cmd/compile/internal/arm64/ssa.go
@@ -221,7 +221,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 
 		for i := 0; i < len(args); i++ {
 			a := args[i]
-			// Offset by size of the unused slot before start of args.
+			// Offset by size of the saved LR slot.
 			addr := ssagen.SpillSlotAddr(a, arm64.REGSP, base.Ctxt.Arch.FixedFrameSize)
 			// Look for double-register operations if we can.
 			if i < len(args)-1 {
diff --git a/src/cmd/compile/internal/ssagen/pgen.go b/src/cmd/compile/internal/ssagen/pgen.go
index f0776172b9264a..0a2010363f8d04 100644
--- a/src/cmd/compile/internal/ssagen/pgen.go
+++ b/src/cmd/compile/internal/ssagen/pgen.go
@@ -393,16 +393,10 @@ func StackOffset(slot ssa.LocalSlot) int32 {
 	case ir.PAUTO:
 		off = n.FrameOffset()
 		if base.Ctxt.Arch.FixedFrameSize == 0 {
-			// x86 return address
 			off -= int64(types.PtrSize)
 		}
 		if buildcfg.FramePointerEnabled {
-			// frame pointer
 			off -= int64(types.PtrSize)
-			if buildcfg.GOARCH == "arm64" {
-				// arm64 return address also
-				off -= int64(types.PtrSize)
-			}
 		}
 	}
 	return int32(off + slot.Off)
diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 107447f04cc4f6..1e2159579dfbf2 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -7150,7 +7150,6 @@ func defframe(s *State, e *ssafn, f *ssa.Func) {
 	// Insert code to zero ambiguously live variables so that the
 	// garbage collector only sees initialized values when it
 	// looks for pointers.
-	// Note: lo/hi are offsets from varp and will be negative.
 	var lo, hi int64
 
 	// Opaque state for backend to use. Current backends use it to
@@ -7158,7 +7157,7 @@ func defframe(s *State, e *ssafn, f *ssa.Func) {
 	var state uint32
 
 	// Iterate through declarations. Autos are sorted in decreasing
-	// frame offset order (least negative to most negative).
+	// frame offset order.
 	for _, n := range e.curfn.Dcl {
 		if !n.Needzero() {
 			continue
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index 281d705a3eb614..743d09a319087d 100644
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -51,6 +51,7 @@ type ctxt7 struct {
 	blitrl     *obj.Prog
 	elitrl     *obj.Prog
 	autosize   int32
+	extrasize  int32
 	instoffset int64
 	pc         int64
 	pool       struct {
@@ -1121,7 +1122,8 @@ func span7(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 		ctxt.Diag("arm64 ops not initialized, call arm64.buildop first")
 	}
 
-	c := ctxt7{ctxt: ctxt, newprog: newprog, cursym: cursym, autosize: int32(p.To.Offset)}
+	c := ctxt7{ctxt: ctxt, newprog: newprog, cursym: cursym, autosize: int32(p.To.Offset & 0xffffffff), extrasize: int32(p.To.Offset >> 32)}
+	p.To.Offset &= 0xffffffff // extrasize is no longer needed
 
 	// Process literal pool and allocate initial program counter for each Prog, before
 	// generating branch veneers.
@@ -2117,8 +2119,8 @@ func (c *ctxt7) aclass(a *obj.Addr) int {
 				// a.Offset is still relative to pseudo-SP.
 				a.Reg = obj.REG_NONE
 			}
-			// The frame top 16 bytes are for LR/FP
-			c.instoffset = int64(c.autosize) + a.Offset - extrasize
+			// The frame top 8 or 16 bytes are for FP
+			c.instoffset = int64(c.autosize) + a.Offset - int64(c.extrasize)
 			return autoclass(c.instoffset)
 
 		case obj.NAME_PARAM:
@@ -2178,8 +2180,8 @@ func (c *ctxt7) aclass(a *obj.Addr) int {
 				// a.Offset is still relative to pseudo-SP.
 				a.Reg = obj.REG_NONE
 			}
-			// The frame top 16 bytes are for LR/FP
-			c.instoffset = int64(c.autosize) + a.Offset - extrasize
+			// The frame top 8 or 16 bytes are for FP
+			c.instoffset = int64(c.autosize) + a.Offset - int64(c.extrasize)
 
 		case obj.NAME_PARAM:
 			if a.Reg == REGSP {
diff --git a/src/cmd/internal/obj/arm64/obj7.go b/src/cmd/internal/obj/arm64/obj7.go
index a697426145185b..2583e46354292f 100644
--- a/src/cmd/internal/obj/arm64/obj7.go
+++ b/src/cmd/internal/obj/arm64/obj7.go
@@ -36,6 +36,7 @@ import (
 	"cmd/internal/src"
 	"cmd/internal/sys"
 	"internal/abi"
+	"internal/buildcfg"
 	"log"
 	"math"
 )
@@ -471,8 +472,6 @@ func (c *ctxt7) rewriteToUseGot(p *obj.Prog) {
 	obj.Nopout(p)
 }
 
-const extrasize = 16 // space needed in the frame for LR+FP
-
 func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 	if cursym.Func().Text == nil || cursym.Func().Text.Link == nil {
 		return
@@ -522,26 +521,33 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			c.autosize = int32(textstksiz)
 
 			if p.Mark&LEAF != 0 && c.autosize == 0 {
-				// A leaf function with no locals needs no frame.
+				// A leaf function with no locals has no frame.
 				p.From.Sym.Set(obj.AttrNoFrame, true)
 			}
 
 			if !p.From.Sym.NoFrame() {
 				// If there is a stack frame at all, it includes
-				// space for the (now unused) word at [SP:SP+8].
+				// space to save the LR.
 				c.autosize += 8
 			}
 
-			// Round up to a multiple of 16.
-			c.autosize += (-c.autosize) & 15
-
 			if c.autosize != 0 {
-				// Allocate an extra 16 bytes at the top of the frame
-				// to save LR+FP.
+				extrasize := int32(0)
+				if c.autosize%16 == 8 {
+					// Allocate extra 8 bytes on the frame top to save FP
+					extrasize = 8
+				} else if c.autosize&(16-1) == 0 {
+					// Allocate extra 16 bytes to save FP for the old frame whose size is 8 mod 16
+					extrasize = 16
+				} else {
+					c.ctxt.Diag("%v: unaligned frame size %d - must be 16 aligned", p, c.autosize-8)
+				}
 				c.autosize += extrasize
 				c.cursym.Func().Locals += extrasize
 
-				p.To.Offset = int64(c.autosize)
+				// low 32 bits for autosize
+				// high 32 bits for extrasize
+				p.To.Offset = int64(c.autosize) | int64(extrasize)<<32
 			} else {
 				// NOFRAME
 				p.To.Offset = 0
@@ -574,72 +580,120 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			var prologueEnd *obj.Prog
 
 			aoffset := c.autosize
-			if aoffset < 16 {
-				log.Fatalf("aoffset too small %d", aoffset)
+			if aoffset > 0xf0 {
+				// MOVD.W offset variant range is -0x100 to 0xf8, SP should be 16-byte aligned.
+				// so the maximum aoffset value is 0xf0.
+				aoffset = 0xf0
 			}
 
+			// Frame is non-empty. Make sure to save link register, even if
+			// it is a leaf function, so that traceback works.
 			q = p
-
-			// Store return address and frame pointer at the top of the stack frame.
-			// STP.W (R29, R30), -16(SP)
-			q1 = obj.Appendp(q, c.newprog)
-			q1.Pos = p.Pos
-			q1.As = ASTP
-			q1.From.Type = obj.TYPE_REGREG
-			q1.From.Reg = REGFP
-			q1.From.Offset = REGLINK
-			q1.To.Type = obj.TYPE_MEM
-			q1.To.Reg = REG_RSP
-			q1.To.Offset = -16
-			q1.Scond = C_XPRE
-
-			prologueEnd = q1
-
-			// Update frame pointer
-			q1 = obj.Appendp(q1, c.newprog)
-			q1.Pos = p.Pos
-			q1.As = AMOVD
-			q1.From.Type = obj.TYPE_REG
-			q1.From.Reg = REGSP
-			q1.To.Type = obj.TYPE_REG
-			q1.To.Reg = REGFP
-
-			// Allocate additional frame space.
-			adj := aoffset - 16
-			if adj > 0 {
-				// SUB $autosize-16, RSP
-				if adj < 1<<12 {
-					q1 = obj.Appendp(q1, c.newprog)
-					q1.Pos = p.Pos
-					q1.As = ASUB
-					q1.From.Type = obj.TYPE_CONST
-					q1.From.Offset = int64(adj)
-					q1.To.Type = obj.TYPE_REG
-					q1.To.Reg = REGSP
-				} else {
-					// Constant too big for atomic subtract.
-					// Materialize in tmp register first.
-					q1 = obj.Appendp(q1, c.newprog)
-					q1.Pos = p.Pos
-					q1.As = AMOVD
-					q1.From.Type = obj.TYPE_CONST
-					q1.From.Offset = int64(adj)
-					q1.To.Type = obj.TYPE_REG
-					q1.To.Reg = REGTMP
-
+			if c.autosize > aoffset {
+				// Frame size is too large for a MOVD.W instruction. Store the frame pointer
+				// register and link register before decrementing SP, so if a signal comes
+				// during the execution of the function prologue, the traceback code will
+				// not see a half-updated stack frame.
+
+				// SUB $autosize, RSP, R20
+				q1 = obj.Appendp(q, c.newprog)
+				q1.Pos = p.Pos
+				q1.As = ASUB
+				q1.From.Type = obj.TYPE_CONST
+				q1.From.Offset = int64(c.autosize)
+				q1.Reg = REGSP
+				q1.To.Type = obj.TYPE_REG
+				q1.To.Reg = REG_R20
+
+				prologueEnd = q1
+
+				// STP (R29, R30), -8(R20)
+				q1 = obj.Appendp(q1, c.newprog)
+				q1.Pos = p.Pos
+				q1.As = ASTP
+				q1.From.Type = obj.TYPE_REGREG
+				q1.From.Reg = REGFP
+				q1.From.Offset = REGLINK
+				q1.To.Type = obj.TYPE_MEM
+				q1.To.Reg = REG_R20
+				q1.To.Offset = -8
+
+				// This is not async preemptible, as if we open a frame
+				// at the current SP, it will clobber the saved LR.
+				q1 = c.ctxt.StartUnsafePoint(q1, c.newprog)
+
+				// MOVD R20, RSP
+				q1 = obj.Appendp(q1, c.newprog)
+				q1.Pos = p.Pos
+				q1.As = AMOVD
+				q1.From.Type = obj.TYPE_REG
+				q1.From.Reg = REG_R20
+				q1.To.Type = obj.TYPE_REG
+				q1.To.Reg = REGSP
+				q1.Spadj = c.autosize
+
+				q1 = c.ctxt.EndUnsafePoint(q1, c.newprog, -1)
+
+				if buildcfg.GOOS == "ios" {
+					// iOS does not support SA_ONSTACK. We will run the signal handler
+					// on the G stack. If we write below SP, it may be clobbered by
+					// the signal handler. So we save FP and LR after decrementing SP.
+					// STP (R29, R30), -8(RSP)
 					q1 = obj.Appendp(q1, c.newprog)
 					q1.Pos = p.Pos
-					q1.As = ASUB
-					q1.From.Type = obj.TYPE_REG
-					q1.From.Reg = REGTMP
-					q1.To.Type = obj.TYPE_REG
+					q1.As = ASTP
+					q1.From.Type = obj.TYPE_REGREG
+					q1.From.Reg = REGFP
+					q1.From.Offset = REGLINK
+					q1.To.Type = obj.TYPE_MEM
 					q1.To.Reg = REGSP
+					q1.To.Offset = -8
 				}
-				q1.Spadj = adj
+			} else {
+				// small frame, update SP and save LR in a single MOVD.W instruction.
+				// So if a signal comes during the execution of the function prologue,
+				// the traceback code will not see a half-updated stack frame.
+				// Also, on Linux, in a cgo binary we may get a SIGSETXID signal
+				// early on before the signal stack is set, as glibc doesn't allow
+				// us to block SIGSETXID. So it is important that we don't write below
+				// the SP until the signal stack is set.
+				// Luckily, all the functions from thread entry to setting the signal
+				// stack have small frames.
+				q1 = obj.Appendp(q, c.newprog)
+				q1.As = AMOVD
+				q1.Pos = p.Pos
+				q1.From.Type = obj.TYPE_REG
+				q1.From.Reg = REGLINK
+				q1.To.Type = obj.TYPE_MEM
+				q1.Scond = C_XPRE
+				q1.To.Offset = int64(-aoffset)
+				q1.To.Reg = REGSP
+				q1.Spadj = aoffset
+
+				prologueEnd = q1
+
+				// Frame pointer.
+				q1 = obj.Appendp(q1, c.newprog)
+				q1.Pos = p.Pos
+				q1.As = AMOVD
+				q1.From.Type = obj.TYPE_REG
+				q1.From.Reg = REGFP
+				q1.To.Type = obj.TYPE_MEM
+				q1.To.Reg = REGSP
+				q1.To.Offset = -8
 			}
 
 			prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
 
+			q1 = obj.Appendp(q1, c.newprog)
+			q1.Pos = p.Pos
+			q1.As = ASUB
+			q1.From.Type = obj.TYPE_CONST
+			q1.From.Offset = 8
+			q1.Reg = REGSP
+			q1.To.Type = obj.TYPE_REG
+			q1.To.Reg = REGFP
+
 		case obj.ARET:
 			nocache(p)
 			if p.From.Type == obj.TYPE_CONST {
@@ -653,56 +707,105 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			}
 			p.To = obj.Addr{}
 			aoffset := c.autosize
-			if aoffset > 0 {
-				if aoffset < 16 {
-					log.Fatalf("aoffset too small %d", aoffset)
-				}
-				adj := aoffset - 16
-				if adj > 0 {
-					if adj < 1<<12 {
-						// ADD $adj, RSP, RSP
-						p.As = AADD
-						p.From.Type = obj.TYPE_CONST
-						p.From.Offset = int64(adj)
-						p.To.Type = obj.TYPE_REG
-						p.To.Reg = REGSP
-					} else {
-						// Put frame size in a separate register and
-						// add it in with a single instruction,
-						// so we never have a partial frame during
-						// the epilog. See issue 73259.
-
-						// MOVD $adj, REGTMP
-						p.As = AMOVD
-						p.From.Type = obj.TYPE_CONST
-						p.From.Offset = int64(adj)
-						p.To.Type = obj.TYPE_REG
-						p.To.Reg = REGTMP
-						// ADD REGTMP, RSP, RSP
-						p = obj.Appendp(p, c.newprog)
-						p.As = AADD
-						p.From.Type = obj.TYPE_REG
-						p.From.Reg = REGTMP
-						p.To.Type = obj.TYPE_REG
-						p.To.Reg = REGSP
-					}
-					p.Spadj = -adj
-				}
-
-				// Pop LR+FP.
-				// LDP.P 16(RSP), (R29, R30)
-				if p.As != obj.ARET {
+			if c.cursym.Func().Text.Mark&LEAF != 0 {
+				if aoffset != 0 {
+					// Restore frame pointer.
+					// ADD $framesize-8, RSP, R29
+					p.As = AADD
+					p.From.Type = obj.TYPE_CONST
+					p.From.Offset = int64(c.autosize) - 8
+					p.Reg = REGSP
+					p.To.Type = obj.TYPE_REG
+					p.To.Reg = REGFP
+
+					// Pop stack frame.
+					// ADD $framesize, RSP, RSP
 					p = obj.Appendp(p, c.newprog)
+					p.As = AADD
+					p.From.Type = obj.TYPE_CONST
+					p.From.Offset = int64(c.autosize)
+					p.To.Type = obj.TYPE_REG
+					p.To.Reg = REGSP
+					p.Spadj = -c.autosize
 				}
-				p.As = ALDP
+			} else if aoffset <= 0xF0 {
+				// small frame, restore LR and update SP in a single MOVD.P instruction.
+				// There is no correctness issue to use a single LDP for LR and FP,
+				// but the instructions are not pattern matched with the prologue's
+				// MOVD.W and MOVD, which may cause performance issue in
+				// store-forwarding.
+
+				// MOVD -8(RSP), R29
+				p.As = AMOVD
 				p.From.Type = obj.TYPE_MEM
 				p.From.Reg = REGSP
-				p.From.Offset = 16
+				p.From.Offset = -8
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REGFP
+				p = obj.Appendp(p, c.newprog)
+
+				// MOVD.P offset(RSP), R30
+				p.As = AMOVD
+				p.From.Type = obj.TYPE_MEM
 				p.Scond = C_XPOST
+				p.From.Offset = int64(aoffset)
+				p.From.Reg = REGSP
+				p.To.Type = obj.TYPE_REG
+				p.To.Reg = REGLINK
+				p.Spadj = -aoffset
+			} else {
+				// LDP -8(RSP), (R29, R30)
+				p.As = ALDP
+				p.From.Type = obj.TYPE_MEM
+				p.From.Offset = -8
+				p.From.Reg = REGSP
 				p.To.Type = obj.TYPE_REGREG
 				p.To.Reg = REGFP
 				p.To.Offset = REGLINK
-				p.Spadj = -16
+
+				if aoffset < 1<<12 {
+					// ADD $aoffset, RSP, RSP
+					q = newprog()
+					q.As = AADD
+					q.From.Type = obj.TYPE_CONST
+					q.From.Offset = int64(aoffset)
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGSP
+					q.Spadj = -aoffset
+					q.Pos = p.Pos
+					q.Link = p.Link
+					p.Link = q
+					p = q
+				} else {
+					// Put frame size in a separate register and
+					// add it in with a single instruction,
+					// so we never have a partial frame during
+					// the epilog. See issue 73259.
+
+					// MOVD $aoffset, REGTMP
+					q = newprog()
+					q.As = AMOVD
+					q.From.Type = obj.TYPE_CONST
+					q.From.Offset = int64(aoffset)
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGTMP
+					q.Pos = p.Pos
+					q.Link = p.Link
+					p.Link = q
+					p = q
+					// ADD REGTMP, RSP, RSP
+					q = newprog()
+					q.As = AADD
+					q.From.Type = obj.TYPE_REG
+					q.From.Reg = REGTMP
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGSP
+					q.Spadj = -aoffset
+					q.Pos = p.Pos
+					q.Link = p.Link
+					p.Link = q
+					p = q
+				}
 			}
 
 			// If enabled, this code emits 'MOV PC, R27' before every 'MOV LR, PC',
@@ -765,11 +868,10 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 				p.From.Type = obj.TYPE_REG
 				p.From.Reg = REGLINK
 			} else {
-				/* MOVD framesize-8(RSP), Rd */
+				/* MOVD (RSP), Rd */
 				p.As = AMOVD
 				p.From.Type = obj.TYPE_MEM
 				p.From.Reg = REGSP
-				p.From.Offset = int64(c.autosize - 8)
 			}
 		}
 		if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 {
@@ -804,12 +906,6 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 			p.From.Reg = int16(REG_LSL + r + (shift&7)<<5)
 			p.From.Offset = 0
 		}
-		if p.To.Type == obj.TYPE_MEM && p.To.Reg == REG_RSP && (p.Scond == C_XPRE || p.Scond == C_XPOST) {
-			p.Spadj += int32(-p.To.Offset)
-		}
-		if p.From.Type == obj.TYPE_MEM && p.From.Reg == REG_RSP && (p.Scond == C_XPRE || p.Scond == C_XPOST) {
-			p.Spadj += int32(-p.From.Offset)
-		}
 	}
 }
 
diff --git a/src/cmd/link/internal/amd64/obj.go b/src/cmd/link/internal/amd64/obj.go
index 761496549f93aa..3a6141b9091eb6 100644
--- a/src/cmd/link/internal/amd64/obj.go
+++ b/src/cmd/link/internal/amd64/obj.go
@@ -51,16 +51,15 @@ func Init() (*sys.Arch, ld.Arch) {
 		Plan9Magic:  uint32(4*26*26 + 7),
 		Plan9_64Bit: true,
 
-		Adddynrel:                 adddynrel,
-		Archinit:                  archinit,
-		Archreloc:                 archreloc,
-		Archrelocvariant:          archrelocvariant,
-		Gentext:                   gentext,
-		Machoreloc1:               machoreloc1,
-		MachorelocSize:            8,
-		PEreloc1:                  pereloc1,
-		TLSIEtoLE:                 tlsIEtoLE,
-		ReturnAddressAtTopOfFrame: true,
+		Adddynrel:        adddynrel,
+		Archinit:         archinit,
+		Archreloc:        archreloc,
+		Archrelocvariant: archrelocvariant,
+		Gentext:          gentext,
+		Machoreloc1:      machoreloc1,
+		MachorelocSize:   8,
+		PEreloc1:         pereloc1,
+		TLSIEtoLE:        tlsIEtoLE,
 
 		ELF: ld.ELFArch{
 			Linuxdynld:     "/lib64/ld-linux-x86-64.so.2",
diff --git a/src/cmd/link/internal/arm64/obj.go b/src/cmd/link/internal/arm64/obj.go
index e1e4ade81835c6..3d358155badbca 100644
--- a/src/cmd/link/internal/arm64/obj.go
+++ b/src/cmd/link/internal/arm64/obj.go
@@ -47,18 +47,17 @@ func Init() (*sys.Arch, ld.Arch) {
 		Dwarfreglr: dwarfRegLR,
 		TrampLimit: 0x7c00000, // 26-bit signed offset * 4, leave room for PLT etc.
 
-		Adddynrel:                 adddynrel,
-		Archinit:                  archinit,
-		Archreloc:                 archreloc,
-		Archrelocvariant:          archrelocvariant,
-		Extreloc:                  extreloc,
-		Gentext:                   gentext,
-		GenSymsLate:               gensymlate,
-		Machoreloc1:               machoreloc1,
-		MachorelocSize:            8,
-		PEreloc1:                  pereloc1,
-		Trampoline:                trampoline,
-		ReturnAddressAtTopOfFrame: true,
+		Adddynrel:        adddynrel,
+		Archinit:         archinit,
+		Archreloc:        archreloc,
+		Archrelocvariant: archrelocvariant,
+		Extreloc:         extreloc,
+		Gentext:          gentext,
+		GenSymsLate:      gensymlate,
+		Machoreloc1:      machoreloc1,
+		MachorelocSize:   8,
+		PEreloc1:         pereloc1,
+		Trampoline:       trampoline,
 
 		ELF: ld.ELFArch{
 			Androiddynld:   "/system/bin/linker64",
diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index c4d12a5488df3c..0003938ef2e036 100644
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -1544,14 +1544,9 @@ func (d *dwctxt) writeframes(fs loader.Sym) dwarfSecInfo {
 				if pcsp.Value > 0 {
 					// The return address is preserved at (CFA-frame_size)
 					// after a stack frame has been allocated.
-					off := -spdelta
-					if thearch.ReturnAddressAtTopOfFrame {
-						// Except arm64, which has it at the top of frame.
-						off = -int64(d.arch.PtrSize)
-					}
 					deltaBuf = append(deltaBuf, dwarf.DW_CFA_offset_extended_sf)
 					deltaBuf = dwarf.AppendUleb128(deltaBuf, uint64(thearch.Dwarfreglr))
-					deltaBuf = dwarf.AppendSleb128(deltaBuf, off/dataAlignmentFactor)
+					deltaBuf = dwarf.AppendSleb128(deltaBuf, -spdelta/dataAlignmentFactor)
 				} else {
 					// The return address is restored into the link register
 					// when a stack frame has been de-allocated.
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 5f5ebfc1d9855c..2c861129b52f9a 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -263,10 +263,6 @@ type Arch struct {
 	// optional override for assignAddress
 	AssignAddress func(ldr *loader.Loader, sect *sym.Section, n int, s loader.Sym, va uint64, isTramp bool) (*sym.Section, int, uint64)
 
-	// Reports whether the return address is stored at the top (highest address)
-	// of the stack frame.
-	ReturnAddressAtTopOfFrame bool
-
 	// ELF specific information.
 	ELF ELFArch
 }
diff --git a/src/cmd/link/internal/ld/stackcheck.go b/src/cmd/link/internal/ld/stackcheck.go
index 14cd3a22384f88..98e7edaeb1477b 100644
--- a/src/cmd/link/internal/ld/stackcheck.go
+++ b/src/cmd/link/internal/ld/stackcheck.go
@@ -9,6 +9,7 @@ import (
 	"cmd/internal/objabi"
 	"cmd/link/internal/loader"
 	"fmt"
+	"internal/buildcfg"
 	"sort"
 	"strings"
 )
@@ -61,6 +62,10 @@ func (ctxt *Link) doStackCheck() {
 	// that there are at least StackLimit bytes available below SP
 	// when morestack returns.
 	limit := objabi.StackNosplit(*flagRace) - sc.callSize
+	if buildcfg.GOARCH == "arm64" {
+		// Need an extra 8 bytes below SP to save FP.
+		limit -= 8
+	}
 
 	// Compute stack heights without any back-tracking information.
 	// This will almost certainly succeed and we can simply
diff --git a/src/cmd/link/internal/x86/obj.go b/src/cmd/link/internal/x86/obj.go
index a4885fde8fd06f..4336f01ea3d536 100644
--- a/src/cmd/link/internal/x86/obj.go
+++ b/src/cmd/link/internal/x86/obj.go
@@ -50,14 +50,13 @@ func Init() (*sys.Arch, ld.Arch) {
 
 		Plan9Magic: uint32(4*11*11 + 7),
 
-		Adddynrel:                 adddynrel,
-		Archinit:                  archinit,
-		Archreloc:                 archreloc,
-		Archrelocvariant:          archrelocvariant,
-		Gentext:                   gentext,
-		Machoreloc1:               machoreloc1,
-		PEreloc1:                  pereloc1,
-		ReturnAddressAtTopOfFrame: true,
+		Adddynrel:        adddynrel,
+		Archinit:         archinit,
+		Archreloc:        archreloc,
+		Archrelocvariant: archrelocvariant,
+		Gentext:          gentext,
+		Machoreloc1:      machoreloc1,
+		PEreloc1:         pereloc1,
 
 		ELF: ld.ELFArch{
 			Linuxdynld:     "/lib/ld-linux.so.2",
diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index aa49a27a75d1e3..a0e82ec830f74b 100644
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -50,7 +50,9 @@ TEXT _rt0_arm64_lib(SB),NOSPLIT,$184
 	CBZ	R4, nocgo
 	MOVD	$_rt0_arm64_lib_go(SB), R0
 	MOVD	$0, R1
+	SUB	$16, RSP		// reserve 16 bytes for sp-8 where fp may be saved.
 	BL	(R4)
+	ADD	$16, RSP
 	B	restore
 
 nocgo:
@@ -369,6 +371,7 @@ switch:
 	BL	runtime·save_g(SB)
 	MOVD	(g_sched+gobuf_sp)(g), R0
 	MOVD	R0, RSP
+	MOVD	(g_sched+gobuf_bp)(g), R29
 	MOVD	$0, (g_sched+gobuf_sp)(g)
 	MOVD	$0, (g_sched+gobuf_bp)(g)
 	RET
@@ -378,8 +381,8 @@ noswitch:
 	// Using a tail call here cleans up tracebacks since we won't stop
 	// at an intermediate systemstack.
 	MOVD	0(R26), R3	// code pointer
-	ADD	$16, RSP
-	LDP.P	16(RSP), (R29,R30)	// restore FP, LR
+	MOVD.P	16(RSP), R30	// restore LR
+	SUB	$8, RSP, R29	// restore FP
 	B	(R3)
 
 // func switchToCrashStack0(fn func())
@@ -1048,7 +1051,7 @@ again:
 // Smashes R0.
 TEXT gosave_systemstack_switch<>(SB),NOSPLIT|NOFRAME,$0
 	MOVD	$runtime·systemstack_switch(SB), R0
-	ADD	$12, R0	// get past prologue
+	ADD	$8, R0	// get past prologue
 	MOVD	R0, (g_sched+gobuf_pc)(g)
 	MOVD	RSP, R0
 	MOVD	R0, (g_sched+gobuf_sp)(g)
@@ -1066,7 +1069,9 @@ TEXT gosave_systemstack_switch<>(SB),NOSPLIT|NOFRAME,$0
 TEXT ·asmcgocall_no_g(SB),NOSPLIT,$0-16
 	MOVD	fn+0(FP), R1
 	MOVD	arg+8(FP), R0
+	SUB	$16, RSP	// skip over saved frame pointer below RSP
 	BL	(R1)
+	ADD	$16, RSP	// skip over saved frame pointer below RSP
 	RET
 
 // func asmcgocall(fn, arg unsafe.Pointer) int32
@@ -1231,9 +1236,9 @@ havem:
 	BL	runtime·save_g(SB)
 	MOVD	(g_sched+gobuf_sp)(g), R4 // prepare stack as R4
 	MOVD	(g_sched+gobuf_pc)(g), R5
-	MOVD	R5, -8(R4)
+	MOVD	R5, -48(R4)
 	MOVD	(g_sched+gobuf_bp)(g), R5
-	MOVD	R5, -16(R4)
+	MOVD	R5, -56(R4)
 	// Gather our arguments into registers.
 	MOVD	fn+0(FP), R1
 	MOVD	frame+8(FP), R2
@@ -1247,7 +1252,7 @@ havem:
 	CALL	(R0) // indirect call to bypass nosplit check. We're on a different stack now.
 
 	// Restore g->sched (== m->curg->sched) from saved values.
-	MOVD	40(RSP), R5
+	MOVD	0(RSP), R5
 	MOVD	R5, (g_sched+gobuf_pc)(g)
 	MOVD	RSP, R4
 	ADD	$48, R4, R4
@@ -1485,57 +1490,10 @@ GLOBL	debugCallFrameTooLarge<>(SB), RODATA, $20	// Size duplicated below
 //
 // This is ABIInternal because Go code injects its PC directly into new
 // goroutine stacks.
-//
-// State before debugger starts doing anything:
-// |   current   |
-// |   stack     |
-// +-------------+ <- SP = origSP
-// stopped executing at PC = origPC
-// some values are in LR (origLR) and FP (origFP)
-//
-// After debugger has done steps 1-6 above:
-// |   current   |
-// |   stack     |
-// +-------------+ <- origSP
-// |    -----    | (used to be a slot to store frame pointer on entry to origPC's frame.)
-// +-------------+
-// |   origLR    |
-// +-------------+ <- SP
-// |    -----    |
-// +-------------+
-// |   argsize   |
-// +-------------+
-// LR = origPC, PC = debugCallV2
-//
-// debugCallV2 then modifies the stack up to the "good" label:
-// |   current   |
-// |   stack     |
-// +-------------+ <- origSP
-// |    -----    | (used to be a slot to store frame pointer on entry to origPC's frame.)
-// +-------------+
-// |   origLR    |
-// +-------------+ <- where debugger left SP
-// |   origPC    |
-// +-------------+
-// |   origFP    |
-// +-------------+ <- FP = SP + 256
-// |   saved     |
-// |  registers  |
-// | (224 bytes) |
-// +-------------+ <- SP + 32
-// |  space for  |
-// |   outargs   |
-// +-------------+ <- SP + 8
-// |   argsize   |
-// +-------------+ <- SP
-
 TEXT runtime·debugCallV2(SB),NOSPLIT|NOFRAME,$0-0
-	MOVD	R30, -8(RSP)		// save origPC
-	MOVD	-16(RSP), R30 		// save argsize in R30 temporarily
-	MOVD.W	R29, -16(RSP)		// push origFP
-	MOVD	RSP, R29		// frame pointer chain now set up
-	SUB	$256, RSP, RSP		// allocate frame
-	MOVD	R30, (RSP)		// Save argsize on the stack
+	STP	(R29, R30), -280(RSP)
+	SUB	$272, RSP, RSP
+	SUB	$8, RSP, R29
 	// Save all registers that may contain pointers so they can be
 	// conservatively scanned.
 	//
@@ -1557,8 +1515,7 @@ TEXT runtime·debugCallV2(SB),NOSPLIT|NOFRAME,$0-0
 	STP	(R0, R1), (4*8)(RSP)
 
 	// Perform a safe-point check.
-	MOVD	264(RSP), R0 // origPC
-	MOVD	R0, 8(RSP)
+	MOVD	R30, 8(RSP) // Caller's PC
 	CALL	runtime·debugCallCheck(SB)
 	MOVD	16(RSP), R0
 	CBZ	R0, good
@@ -1602,7 +1559,7 @@ good:
 	CALL	runtime·debugCallWrap(SB);	\
 	JMP	restore
 
-	MOVD	(RSP), R0 // the argument frame size
+	MOVD	256(RSP), R0 // the argument frame size
 	DEBUG_CALL_DISPATCH(debugCall32<>, 32)
 	DEBUG_CALL_DISPATCH(debugCall64<>, 64)
 	DEBUG_CALL_DISPATCH(debugCall128<>, 128)
@@ -1650,9 +1607,9 @@ restore:
 	LDP	(6*8)(RSP), (R2, R3)
 	LDP	(4*8)(RSP), (R0, R1)
 
-	MOVD	272(RSP), R30		// restore old lr (saved by (*sigctxt).pushCall)
-	LDP	256(RSP), (R29, R27)	// restore old fp, set up resumption address
-	ADD	$288, RSP, RSP		// Pop frame, LR+FP, and block pushed by (*sigctxt).pushCall
+	LDP	-8(RSP), (R29, R27)
+	ADD	$288, RSP, RSP // Add 16 more bytes, see saveSigContext
+	MOVD	-16(RSP), R30 // restore old lr
 	JMP	(R27)
 
 // runtime.debugCallCheck assumes that functions defined with the
diff --git a/src/runtime/mkpreempt.go b/src/runtime/mkpreempt.go
index 9064cae039f00d..769c4ffc5c9eeb 100644
--- a/src/runtime/mkpreempt.go
+++ b/src/runtime/mkpreempt.go
@@ -488,18 +488,26 @@ func genARM64(g *gen) {
 		l.stack += 8 // SP needs 16-byte alignment
 	}
 
-	// allocate frame, save PC (in R30), FP (in R29) of interrupted instruction
-	p("STP.W (R29, R30), -16(RSP)")
-	p("MOVD RSP, R29") // set up new frame pointer
+	// allocate frame, save PC of interrupted instruction (in LR)
+	p("MOVD R30, %d(RSP)", -l.stack)
 	p("SUB $%d, RSP", l.stack)
+	p("MOVD R29, -8(RSP)") // save frame pointer (only used on Linux)
+	p("SUB $8, RSP, R29")  // set up new frame pointer
+	// On iOS, save the LR again after decrementing SP. We run the
+	// signal handler on the G stack (as it doesn't support sigaltstack),
+	// so any writes below SP may be clobbered.
+	p("#ifdef GOOS_ios")
+	p("MOVD R30, (RSP)")
+	p("#endif")
 
 	l.save(g)
 	p("CALL ·asyncPreempt2(SB)")
 	l.restore(g)
 
-	p("MOVD %d(RSP), R30", l.stack+16)    // sigctxt.pushCall has pushed LR (at interrupt) on stack, restore it
-	p("LDP %d(RSP), (R29, R27)", l.stack) // Restore frame pointer. Load PC into regtmp.
-	p("ADD $%d, RSP", l.stack+32)         // pop frame (including the space pushed by sigctxt.pushCall)
+	p("MOVD %d(RSP), R30", l.stack) // sigctxt.pushCall has pushed LR (at interrupt) on stack, restore it
+	p("MOVD -8(RSP), R29")          // restore frame pointer
+	p("MOVD (RSP), R27")            // load PC to REGTMP
+	p("ADD $%d, RSP", l.stack+16)   // pop frame (including the space pushed by sigctxt.pushCall)
 	p("RET (R27)")
 }
 
diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index 04b3afe1682765..8c91c9435abd18 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -1379,10 +1379,10 @@ func recovery(gp *g) {
 		// the caller
 		gp.sched.bp = fp - 2*goarch.PtrSize
 	case goarch.IsArm64 != 0:
-		// on arm64, the first two words of the frame are caller's PC
-		// (the saved LR register) and the caller's BP.
-		// Coincidentally, the same as amd64.
-		gp.sched.bp = fp - 2*goarch.PtrSize
+		// on arm64, the architectural bp points one word higher
+		// than the sp. fp is totally useless to us here, because it
+		// only gets us to the caller's fp.
+		gp.sched.bp = sp - goarch.PtrSize
 	}
 	gogo(&gp.sched)
 }
diff --git a/src/runtime/preempt_arm64.s b/src/runtime/preempt_arm64.s
index f4248cac257550..31ec9d940f76d4 100644
--- a/src/runtime/preempt_arm64.s
+++ b/src/runtime/preempt_arm64.s
@@ -4,9 +4,13 @@
 #include "textflag.h"
 
 TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
-	STP.W (R29, R30), -16(RSP)
-	MOVD RSP, R29
+	MOVD R30, -496(RSP)
 	SUB $496, RSP
+	MOVD R29, -8(RSP)
+	SUB $8, RSP, R29
+	#ifdef GOOS_ios
+	MOVD R30, (RSP)
+	#endif
 	STP (R0, R1), 8(RSP)
 	STP (R2, R3), 24(RSP)
 	STP (R4, R5), 40(RSP)
@@ -74,7 +78,8 @@ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
 	LDP 40(RSP), (R4, R5)
 	LDP 24(RSP), (R2, R3)
 	LDP 8(RSP), (R0, R1)
-	MOVD 512(RSP), R30
-	LDP 496(RSP), (R29, R27)
-	ADD $528, RSP
+	MOVD 496(RSP), R30
+	MOVD -8(RSP), R29
+	MOVD (RSP), R27
+	ADD $512, RSP
 	RET (R27)
diff --git a/src/runtime/race_arm64.s b/src/runtime/race_arm64.s
index feaa328d4c0d8a..5df650105bb4d5 100644
--- a/src/runtime/race_arm64.s
+++ b/src/runtime/race_arm64.s
@@ -397,7 +397,7 @@ TEXT	racecallatomic<>(SB), NOSPLIT, $0
 	// R3 = addr of incoming arg list
 
 	// Trigger SIGSEGV early.
-	MOVD	72(RSP), R3	// 1st arg is addr. after two small frames (32 bytes each), get it at 72(RSP)
+	MOVD	40(RSP), R3	// 1st arg is addr. after two times BL, get it at 40(RSP)
 	MOVB	(R3), R13	// segv here if addr is bad
 	// Check that addr is within [arenastart, arenaend) or within [racedatastart, racedataend).
 	MOVD	runtime·racearenastart(SB), R10
@@ -417,11 +417,10 @@ racecallatomic_ok:
 	// Addr is within the good range, call the atomic function.
 	load_g
 	MOVD	g_racectx(g), R0	// goroutine context
-	MOVD	56(RSP), R1	// caller pc
+	MOVD	16(RSP), R1	// caller pc
 	MOVD	R9, R2	// pc
-	ADD	$72, RSP, R3
-	BL	racecall<>(SB)
-	RET
+	ADD	$40, RSP, R3
+	JMP	racecall<>(SB)	// does not return
 racecallatomic_ignore:
 	// Addr is outside the good range.
 	// Call __tsan_go_ignore_sync_begin to ignore synchronization during the atomic op.
@@ -436,9 +435,9 @@ racecallatomic_ignore:
 	// racecall will call LLVM race code which might clobber R28 (g)
 	load_g
 	MOVD	g_racectx(g), R0	// goroutine context
-	MOVD	56(RSP), R1	// caller pc
+	MOVD	16(RSP), R1	// caller pc
 	MOVD	R9, R2	// pc
-	ADD	$72, RSP, R3	// arguments
+	ADD	$40, RSP, R3	// arguments
 	BL	racecall<>(SB)
 	// Call __tsan_go_ignore_sync_end.
 	MOVD	$__tsan_go_ignore_sync_end(SB), R9
@@ -477,6 +476,10 @@ TEXT	racecall<>(SB), NOSPLIT|NOFRAME, $0-0
 	MOVD	(g_sched+gobuf_sp)(R11), R12
 	MOVD	R12, RSP
 call:
+	// Decrement SP past where the frame pointer is saved in the Go arm64
+	// ABI (one word below the stack pointer) so the race detector library
+	// code doesn't clobber it
+	SUB	$16, RSP
 	BL	R9
 	MOVD	R19, RSP
 	JMP	(R20)
diff --git a/src/runtime/signal_arm64.go b/src/runtime/signal_arm64.go
index 61dad507219caf..af7d29f9de1d31 100644
--- a/src/runtime/signal_arm64.go
+++ b/src/runtime/signal_arm64.go
@@ -8,6 +8,7 @@ package runtime
 
 import (
 	"internal/abi"
+	"internal/goarch"
 	"internal/runtime/sys"
 	"unsafe"
 )
@@ -62,11 +63,18 @@ func (c *sigctxt) preparePanic(sig uint32, gp *g) {
 	// We arrange lr, and pc to pretend the panicking
 	// function calls sigpanic directly.
 	// Always save LR to stack so that panics in leaf
-	// functions are correctly handled.
-	// This extra space is known to gentraceback.
+	// functions are correctly handled. This smashes
+	// the stack frame but we're not going back there
+	// anyway.
 	sp := c.sp() - sys.StackAlign // needs only sizeof uint64, but must align the stack
 	c.set_sp(sp)
 	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.lr()
+	// Make sure a valid frame pointer is saved on the stack so that the
+	// frame pointer checks in adjustframe are happy, if they're enabled.
+	// Frame pointer unwinding won't visit the sigpanic frame, since
+	// sigpanic will save the same frame pointer before calling into a panic
+	// function.
+	*(*uint64)(unsafe.Pointer(uintptr(sp - goarch.PtrSize))) = c.r29()
 
 	pc := gp.sigpc
 
@@ -88,6 +96,10 @@ func (c *sigctxt) pushCall(targetPC, resumePC uintptr) {
 	sp := c.sp() - 16 // SP needs 16-byte alignment
 	c.set_sp(sp)
 	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.lr()
+	// Make sure a valid frame pointer is saved on the stack so that the
+	// frame pointer checks in adjustframe are happy, if they're enabled.
+	// This is not actually used for unwinding.
+	*(*uint64)(unsafe.Pointer(uintptr(sp - goarch.PtrSize))) = c.r29()
 	// Set up PC and LR to pretend the function being signaled
 	// calls targetPC at resumePC.
 	c.set_lr(uint64(resumePC))
diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index 5eaceec6da14d5..55e97e77afa957 100644
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -579,27 +579,23 @@ var ptrnames = []string{
 // |  args to callee  |
 // +------------------+ <- frame->sp
 //
-// (arm64)
+// (arm)
 // +------------------+
 // | args from caller |
 // +------------------+ <- frame->argp
-// |          |
-// +------------------+ <- frame->fp (aka caller's sp)
-// |  return address  |
+// | caller's retaddr |
 // +------------------+
-// |  caller's FP     |  (frame pointer always enabled: TODO)
+// |  caller's FP (*) | (*) on ARM64, if framepointer_enabled && varp > sp
 // +------------------+ <- frame->varp
 // |     locals       |
 // +------------------+
 // |  args to callee  |
 // +------------------+
-// |          |
+// |  return address  |
 // +------------------+ <- frame->sp
 //
 // varp > sp means that the function has a frame;
 // varp == sp means frameless function.
-//
-// Alignment padding, if needed, will be between "locals" and "args to callee".
 
 type adjustinfo struct {
 	old   stack
@@ -713,8 +709,7 @@ func adjustframe(frame *stkframe, adjinfo *adjustinfo) {
 	}
 
 	// Adjust saved frame pointer if there is one.
-	if goarch.ArchFamily == goarch.AMD64 && frame.argp-frame.varp == 2*goarch.PtrSize ||
-		goarch.ArchFamily == goarch.ARM64 && frame.argp-frame.varp == 3*goarch.PtrSize {
+	if (goarch.ArchFamily == goarch.AMD64 || goarch.ArchFamily == goarch.ARM64) && frame.argp-frame.varp == 2*goarch.PtrSize {
 		if stackDebug >= 3 {
 			print("      saved bp\n")
 		}
@@ -728,7 +723,10 @@ func adjustframe(frame *stkframe, adjinfo *adjustinfo) {
 				throw("bad frame pointer")
 			}
 		}
-		// This is the caller's frame pointer saved in the current frame.
+		// On AMD64, this is the caller's frame pointer saved in the current
+		// frame.
+		// On ARM64, this is the frame pointer of the caller's caller saved
+		// by the caller in its frame (one word below its SP).
 		adjustpointer(adjinfo, unsafe.Pointer(frame.varp))
 	}
 
diff --git a/src/runtime/testdata/testprog/badtraceback.go b/src/runtime/testdata/testprog/badtraceback.go
index 36575f765db9a5..455118a54371d7 100644
--- a/src/runtime/testdata/testprog/badtraceback.go
+++ b/src/runtime/testdata/testprog/badtraceback.go
@@ -41,11 +41,6 @@ func badLR2(arg int) {
 	if runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" {
 		lrOff = 32 // FIXED_FRAME or sys.MinFrameSize
 	}
-	if runtime.GOARCH == "arm64" {
-		// skip 8 bytes at bottom of parent frame, then point
-		// to the 8 bytes of the saved PC at the top of the frame.
-		lrOff = 16
-	}
 	lrPtr := (*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&arg)) - lrOff))
 	*lrPtr = 0xbad
 
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index 1c3e679a02bdaf..8882c306edb736 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -175,11 +175,6 @@ func (u *unwinder) initAt(pc0, sp0, lr0 uintptr, gp *g, flags unwindFlags) {
 	// Start in the caller's frame.
 	if frame.pc == 0 {
 		if usesLR {
-			// TODO: this isn't right on arm64. But also, this should
-			// ~never happen. Calling a nil function will panic
-			// when loading the PC out of the closure, not when
-			// branching to that PC. (Closures should always have
-			// valid PCs in their first word.)
 			frame.pc = *(*uintptr)(unsafe.Pointer(frame.sp))
 			frame.lr = 0
 		} else {
@@ -374,11 +369,7 @@ func (u *unwinder) resolveInternal(innermost, isSyscall bool) {
 		var lrPtr uintptr
 		if usesLR {
 			if innermost && frame.sp < frame.fp || frame.lr == 0 {
-				if GOARCH == "arm64" {
-					lrPtr = frame.fp - goarch.PtrSize
-				} else {
-					lrPtr = frame.sp
-				}
+				lrPtr = frame.sp
 				frame.lr = *(*uintptr)(unsafe.Pointer(lrPtr))
 			}
 		} else {
@@ -394,17 +385,24 @@ func (u *unwinder) resolveInternal(innermost, isSyscall bool) {
 		// On x86, call instruction pushes return PC before entering new function.
 		frame.varp -= goarch.PtrSize
 	}
-	if GOARCH == "arm64" && frame.varp > frame.sp {
-		frame.varp -= goarch.PtrSize // LR have been saved, skip over it.
-	}
 
 	// For architectures with frame pointers, if there's
 	// a frame, then there's a saved frame pointer here.
 	//
 	// NOTE: This code is not as general as it looks.
-	// On x86 and arm64, the ABI is to save the frame pointer word at the
+	// On x86, the ABI is to save the frame pointer word at the
 	// top of the stack frame, so we have to back down over it.
-	// No other architectures are framepointer-enabled at the moment.
+	// On arm64, the frame pointer should be at the bottom of
+	// the stack (with R29 (aka FP) = RSP), in which case we would
+	// not want to do the subtraction here. But we started out without
+	// any frame pointer, and when we wanted to add it, we didn't
+	// want to break all the assembly doing direct writes to 8(RSP)
+	// to set the first parameter to a called function.
+	// So we decided to write the FP link *below* the stack pointer
+	// (with R29 = RSP - 8 in Go functions).
+	// This is technically ABI-compatible but not standard.
+	// And it happens to end up mimicking the x86 layout.
+	// Other architectures may make different decisions.
 	if frame.varp > frame.sp && framepointer_enabled {
 		frame.varp -= goarch.PtrSize
 	}
@@ -564,7 +562,7 @@ func (u *unwinder) finishInternal() {
 	gp := u.g.ptr()
 	if u.flags&(unwindPrintErrors|unwindSilentErrors) == 0 && u.frame.sp != gp.stktopsp {
 		print("runtime: g", gp.goid, ": frame.sp=", hex(u.frame.sp), " top=", hex(gp.stktopsp), "\n")
-		print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "]\n")
+		print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "\n")
 		throw("traceback did not unwind completely")
 	}
 }
diff --git a/test/nosplit.go b/test/nosplit.go
index 1f943fa18c3f58..4b4c93b1d067c5 100644
--- a/test/nosplit.go
+++ b/test/nosplit.go
@@ -142,7 +142,7 @@ start 136
 # (CallSize is 32 on ppc64, 8 on amd64 for frame pointer.)
 start 96 nosplit
 start 100 nosplit; REJECT ppc64 ppc64le
-start 104 nosplit; REJECT ppc64 ppc64le
+start 104 nosplit; REJECT ppc64 ppc64le arm64
 start 108 nosplit; REJECT ppc64 ppc64le
 start 112 nosplit; REJECT ppc64 ppc64le arm64
 start 116 nosplit; REJECT ppc64 ppc64le
@@ -160,7 +160,7 @@ start 136 nosplit; REJECT
 # Because AMD64 uses frame pointer, it has 8 fewer bytes.
 start 96 nosplit call f; f 0 nosplit
 start 100 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le
-start 104 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le
+start 104 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le arm64
 start 108 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le
 start 112 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le amd64 arm64
 start 116 nosplit call f; f 0 nosplit; REJECT ppc64 ppc64le amd64
@@ -176,7 +176,7 @@ start 136 nosplit call f; f 0 nosplit; REJECT
 # Architectures differ in the same way as before.
 start 96 nosplit call f; f 0 call f
 start 100 nosplit call f; f 0 call f; REJECT ppc64 ppc64le
-start 104 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64
+start 104 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64 arm64
 start 108 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64
 start 112 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64 arm64
 start 116 nosplit call f; f 0 call f; REJECT ppc64 ppc64le amd64
@@ -189,7 +189,7 @@ start 136 nosplit call f; f 0 call f; REJECT
 # Indirect calls are assumed to be splitting functions.
 start 96 nosplit callind
 start 100 nosplit callind; REJECT ppc64 ppc64le
-start 104 nosplit callind; REJECT ppc64 ppc64le amd64
+start 104 nosplit callind; REJECT ppc64 ppc64le amd64 arm64
 start 108 nosplit callind; REJECT ppc64 ppc64le amd64
 start 112 nosplit callind; REJECT ppc64 ppc64le amd64 arm64
 start 116 nosplit callind; REJECT ppc64 ppc64le amd64

From f86ddb54b5b8e4cb30b8fe2f9f3a2c0c172e7c37 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 19:21:56 -0400
Subject: [PATCH 075/229] cmd/go: refactor usage of `ForceUseModules`

This commit refactors usage of the global variable `ForceUseModules`
to the global LoaderState field of the same name.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf 'mv State.forceUseModules State.ForceUseModules'
rf 'ex { ForceUseModules -> LoaderState.ForceUseModules }'
for dir in load modcmd modget run toolchain work workcmd ; do
  cd ../${dir}
  rf 'ex {
    import "cmd/go/internal/modload";
    modload.ForceUseModules -> modload.LoaderState.ForceUseModules
  }'
done
cd ../modload
rf 'add State.initialized \
// ForceUseModules may be set to force modules to be enabled when\
// GO111MODULE=auto or to report an error when GO111MODULE=off.'
rf 'rm ForceUseModules'

Change-Id: Ibdecfd273ff672516c9eb86279e5dfc6cdecb2ea
Reviewed-on: https://go-review.googlesource.com/c/go/+/698057
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/load/pkg.go         |  2 +-
 src/cmd/go/internal/modcmd/download.go  |  2 +-
 src/cmd/go/internal/modcmd/graph.go     |  2 +-
 src/cmd/go/internal/modcmd/init.go      |  2 +-
 src/cmd/go/internal/modcmd/tidy.go      |  2 +-
 src/cmd/go/internal/modcmd/vendor.go    |  2 +-
 src/cmd/go/internal/modcmd/verify.go    |  2 +-
 src/cmd/go/internal/modcmd/why.go       |  2 +-
 src/cmd/go/internal/modget/get.go       |  2 +-
 src/cmd/go/internal/modload/init.go     | 21 ++++++++++-----------
 src/cmd/go/internal/run/run.go          |  2 +-
 src/cmd/go/internal/toolchain/select.go |  4 ++--
 src/cmd/go/internal/work/build.go       |  2 +-
 src/cmd/go/internal/workcmd/init.go     |  2 +-
 src/cmd/go/internal/workcmd/sync.go     |  2 +-
 src/cmd/go/internal/workcmd/use.go      |  2 +-
 16 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index 1f791546f90088..48b2e70d74b759 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -3348,7 +3348,7 @@ func GoFilesPackage(ctx context.Context, opts PackageOpts, gofiles []string) *Pa
 // would cause it to be interpreted differently if it were the main module
 // (replace, exclude).
 func PackagesAndErrorsOutsideModule(ctx context.Context, opts PackageOpts, args []string) ([]*Package, error) {
-	if !modload.ForceUseModules {
+	if !modload.LoaderState.ForceUseModules {
 		panic("modload.ForceUseModules must be true")
 	}
 	if modload.RootMode != modload.NoRoot {
diff --git a/src/cmd/go/internal/modcmd/download.go b/src/cmd/go/internal/modcmd/download.go
index 2f4feae8f254b2..6d12d689f0ff51 100644
--- a/src/cmd/go/internal/modcmd/download.go
+++ b/src/cmd/go/internal/modcmd/download.go
@@ -112,7 +112,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	modload.InitWorkfile()
 
 	// Check whether modules are enabled and whether we're in a module.
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.ExplicitWriteGoMod = true
 	haveExplicitArgs := len(args) > 0
 
diff --git a/src/cmd/go/internal/modcmd/graph.go b/src/cmd/go/internal/modcmd/graph.go
index 172c1dda5ce8fb..4abae33129ab6b 100644
--- a/src/cmd/go/internal/modcmd/graph.go
+++ b/src/cmd/go/internal/modcmd/graph.go
@@ -57,7 +57,7 @@ func runGraph(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) > 0 {
 		base.Fatalf("go: 'go mod graph' accepts no arguments")
 	}
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.RootMode = modload.NeedRoot
 
 	goVersion := graphGo.String()
diff --git a/src/cmd/go/internal/modcmd/init.go b/src/cmd/go/internal/modcmd/init.go
index 356a0569913edf..618c673bf86f24 100644
--- a/src/cmd/go/internal/modcmd/init.go
+++ b/src/cmd/go/internal/modcmd/init.go
@@ -43,6 +43,6 @@ func runInit(ctx context.Context, cmd *base.Command, args []string) {
 		modPath = args[0]
 	}
 
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.CreateModFile(ctx, modPath) // does all the hard work
 }
diff --git a/src/cmd/go/internal/modcmd/tidy.go b/src/cmd/go/internal/modcmd/tidy.go
index 2efa33a7c343dd..dde70c6d74181e 100644
--- a/src/cmd/go/internal/modcmd/tidy.go
+++ b/src/cmd/go/internal/modcmd/tidy.go
@@ -119,7 +119,7 @@ func runTidy(ctx context.Context, cmd *base.Command, args []string) {
 	// those packages. In order to make 'go test' reproducible for the packages
 	// that are in 'all' but outside of the main module, we must explicitly
 	// request that their test dependencies be included.
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.RootMode = modload.NeedRoot
 
 	goVersion := tidyGo.String()
diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index e1a9081a95ff80..bd3d8d602e2382 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -77,7 +77,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 	if len(args) != 0 {
 		base.Fatalf("go: 'go mod vendor' accepts no arguments")
 	}
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.RootMode = modload.NeedRoot
 
 	loadOpts := modload.PackageOpts{
diff --git a/src/cmd/go/internal/modcmd/verify.go b/src/cmd/go/internal/modcmd/verify.go
index d07f730c5d0dcf..ecd25d3a40e610 100644
--- a/src/cmd/go/internal/modcmd/verify.go
+++ b/src/cmd/go/internal/modcmd/verify.go
@@ -50,7 +50,7 @@ func runVerify(ctx context.Context, cmd *base.Command, args []string) {
 		// NOTE(rsc): Could take a module pattern.
 		base.Fatalf("go: verify takes no arguments")
 	}
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.RootMode = modload.NeedRoot
 
 	// Only verify up to GOMAXPROCS zips at once.
diff --git a/src/cmd/go/internal/modcmd/why.go b/src/cmd/go/internal/modcmd/why.go
index 198672d8064113..6c4bf8abab17ee 100644
--- a/src/cmd/go/internal/modcmd/why.go
+++ b/src/cmd/go/internal/modcmd/why.go
@@ -64,7 +64,7 @@ func init() {
 
 func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 	modload.InitWorkfile()
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.RootMode = modload.NeedRoot
 	modload.ExplicitWriteGoMod = true // don't write go.mod in ListModules
 
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index 25dbf3972fd465..167f515be98a7d 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -298,7 +298,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 		base.Fatalf("go: -insecure flag is no longer supported; use GOINSECURE instead")
 	}
 
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 
 	// Do not allow any updating of go.mod until we've applied
 	// all the requested changes and checked that the result matches
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index d7d532ec942665..264c02ef6db100 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -41,10 +41,6 @@ var (
 	// RootMode determines whether a module root is needed.
 	RootMode Root
 
-	// ForceUseModules may be set to force modules to be enabled when
-	// GO111MODULE=auto or to report an error when GO111MODULE=off.
-	ForceUseModules bool
-
 	allowMissingModuleImports bool
 
 	// ExplicitWriteGoMod prevents LoadPackages, ListModules, and other functions
@@ -96,7 +92,7 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 
 	// Reset the state to a clean state.
 	oldstate := setState(State{})
-	ForceUseModules = true
+	LoaderState.ForceUseModules = true
 
 	// Load in workspace mode.
 	InitWorkfile()
@@ -406,7 +402,7 @@ func Reset() {
 func setState(s State) State {
 	oldState := State{
 		initialized:     LoaderState.initialized,
-		forceUseModules: ForceUseModules,
+		ForceUseModules: LoaderState.ForceUseModules,
 		rootMode:        RootMode,
 		modRoots:        modRoots,
 		modulesEnabled:  cfg.ModulesEnabled,
@@ -414,7 +410,7 @@ func setState(s State) State {
 		requirements:    requirements,
 	}
 	LoaderState.initialized = s.initialized
-	ForceUseModules = s.forceUseModules
+	LoaderState.ForceUseModules = s.ForceUseModules
 	RootMode = s.rootMode
 	modRoots = s.modRoots
 	cfg.ModulesEnabled = s.modulesEnabled
@@ -429,8 +425,11 @@ func setState(s State) State {
 }
 
 type State struct {
-	initialized     bool
-	forceUseModules bool
+	initialized bool
+
+	// ForceUseModules may be set to force modules to be enabled when
+	// GO111MODULE=auto or to report an error when GO111MODULE=off.
+	ForceUseModules bool
 	rootMode        Root
 	modRoots        []string
 	modulesEnabled  bool
@@ -465,11 +464,11 @@ func Init() {
 	default:
 		base.Fatalf("go: unknown environment setting GO111MODULE=%s", env)
 	case "auto":
-		mustUseModules = ForceUseModules
+		mustUseModules = LoaderState.ForceUseModules
 	case "on", "":
 		mustUseModules = true
 	case "off":
-		if ForceUseModules {
+		if LoaderState.ForceUseModules {
 			base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
 		}
 		mustUseModules = false
diff --git a/src/cmd/go/internal/run/run.go b/src/cmd/go/internal/run/run.go
index b81b1a007bd79d..05ea5eaa15eea4 100644
--- a/src/cmd/go/internal/run/run.go
+++ b/src/cmd/go/internal/run/run.go
@@ -76,7 +76,7 @@ func runRun(ctx context.Context, cmd *base.Command, args []string) {
 		// This must be done before modload.Init, but we need to call work.BuildInit
 		// before loading packages, since it affects package locations, e.g.,
 		// for -race and -msan.
-		modload.ForceUseModules = true
+		modload.LoaderState.ForceUseModules = true
 		modload.RootMode = modload.NoRoot
 		modload.AllowMissingModuleImports()
 		modload.Init()
diff --git a/src/cmd/go/internal/toolchain/select.go b/src/cmd/go/internal/toolchain/select.go
index e8712613366e8c..8f55076c6282c2 100644
--- a/src/cmd/go/internal/toolchain/select.go
+++ b/src/cmd/go/internal/toolchain/select.go
@@ -353,7 +353,7 @@ func Exec(gotoolchain string) {
 
 	// Set up modules without an explicit go.mod, to download distribution.
 	modload.Reset()
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.RootMode = modload.NoRoot
 	modload.Init()
 
@@ -692,7 +692,7 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 	// command lines if we add new flags in the future.
 
 	// Set up modules without an explicit go.mod, to download go.mod.
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.RootMode = modload.NoRoot
 	modload.Init()
 	defer modload.Reset()
diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index 6741b39f051cd6..21bbab1bf47463 100644
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -859,7 +859,7 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
 //
 // See golang.org/issue/40276 for details and rationale.
 func installOutsideModule(ctx context.Context, args []string) {
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.RootMode = modload.NoRoot
 	modload.AllowMissingModuleImports()
 	modload.Init()
diff --git a/src/cmd/go/internal/workcmd/init.go b/src/cmd/go/internal/workcmd/init.go
index 02240b8189fab5..52185391c115b3 100644
--- a/src/cmd/go/internal/workcmd/init.go
+++ b/src/cmd/go/internal/workcmd/init.go
@@ -46,7 +46,7 @@ func init() {
 func runInit(ctx context.Context, cmd *base.Command, args []string) {
 	modload.InitWorkfile()
 
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 
 	gowork := modload.WorkFilePath()
 	if gowork == "" {
diff --git a/src/cmd/go/internal/workcmd/sync.go b/src/cmd/go/internal/workcmd/sync.go
index 719cf76c9bf12d..800dd15dd6f6d1 100644
--- a/src/cmd/go/internal/workcmd/sync.go
+++ b/src/cmd/go/internal/workcmd/sync.go
@@ -48,7 +48,7 @@ func init() {
 }
 
 func runSync(ctx context.Context, cmd *base.Command, args []string) {
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.InitWorkfile()
 	if modload.WorkFilePath() == "" {
 		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
diff --git a/src/cmd/go/internal/workcmd/use.go b/src/cmd/go/internal/workcmd/use.go
index afbe99d3a480db..2842163517892c 100644
--- a/src/cmd/go/internal/workcmd/use.go
+++ b/src/cmd/go/internal/workcmd/use.go
@@ -61,7 +61,7 @@ func init() {
 }
 
 func runUse(ctx context.Context, cmd *base.Command, args []string) {
-	modload.ForceUseModules = true
+	modload.LoaderState.ForceUseModules = true
 	modload.InitWorkfile()
 	gowork := modload.WorkFilePath()
 	if gowork == "" {

From 2e52060084ff170097347457525f0debde91aea9 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 19:34:40 -0400
Subject: [PATCH 076/229] cmd/go: refactor usage of `RootMode`

This commit refactors usage of the global variable `RootMode` to the
global LoaderState variable of the same name.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf 'mv State.rootMode State.RootMode'
for dir in load modcmd run tool toolchain work ; do
  cd ../${dir}
  rf 'ex {
    import "cmd/go/internal/modload";
    modload.RootMode -> modload.LoaderState.RootMode
  }'
done
cd ../modload
rf 'ex { RootMode -> LoaderState.RootMode }'
rf 'add State.ForceUseModules \
// RootMode determines whether a module root is needed.'
rf 'rm RootMode'

Change-Id: Ib5e513ee570dfc3b01cc974fe32944e5e391fd82
Reviewed-on: https://go-review.googlesource.com/c/go/+/698058
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/load/godebug.go        |  2 +-
 src/cmd/go/internal/load/pkg.go            |  2 +-
 src/cmd/go/internal/modcmd/graph.go        |  2 +-
 src/cmd/go/internal/modcmd/tidy.go         |  2 +-
 src/cmd/go/internal/modcmd/vendor.go       |  2 +-
 src/cmd/go/internal/modcmd/verify.go       |  2 +-
 src/cmd/go/internal/modcmd/why.go          |  2 +-
 src/cmd/go/internal/modload/import_test.go |  6 ++--
 src/cmd/go/internal/modload/init.go        | 33 +++++++++++-----------
 src/cmd/go/internal/run/run.go             |  2 +-
 src/cmd/go/internal/tool/tool.go           |  2 +-
 src/cmd/go/internal/toolchain/select.go    |  4 +--
 src/cmd/go/internal/work/build.go          |  2 +-
 13 files changed, 31 insertions(+), 32 deletions(-)

diff --git a/src/cmd/go/internal/load/godebug.go b/src/cmd/go/internal/load/godebug.go
index 8ea8ffab1aea1f..ff184384567afe 100644
--- a/src/cmd/go/internal/load/godebug.go
+++ b/src/cmd/go/internal/load/godebug.go
@@ -50,7 +50,7 @@ func defaultGODEBUG(p *Package, directives, testDirectives, xtestDirectives []bu
 		return ""
 	}
 	goVersion := modload.MainModules.GoVersion()
-	if modload.RootMode == modload.NoRoot && p.Module != nil {
+	if modload.LoaderState.RootMode == modload.NoRoot && p.Module != nil {
 		// This is go install pkg@version or go run pkg@version.
 		// Use the Go version from the package.
 		// If there isn't one, then assume Go 1.20,
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index 48b2e70d74b759..27a1fbfff836fa 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -3351,7 +3351,7 @@ func PackagesAndErrorsOutsideModule(ctx context.Context, opts PackageOpts, args
 	if !modload.LoaderState.ForceUseModules {
 		panic("modload.ForceUseModules must be true")
 	}
-	if modload.RootMode != modload.NoRoot {
+	if modload.LoaderState.RootMode != modload.NoRoot {
 		panic("modload.RootMode must be NoRoot")
 	}
 
diff --git a/src/cmd/go/internal/modcmd/graph.go b/src/cmd/go/internal/modcmd/graph.go
index 4abae33129ab6b..5f47260e188292 100644
--- a/src/cmd/go/internal/modcmd/graph.go
+++ b/src/cmd/go/internal/modcmd/graph.go
@@ -58,7 +58,7 @@ func runGraph(ctx context.Context, cmd *base.Command, args []string) {
 		base.Fatalf("go: 'go mod graph' accepts no arguments")
 	}
 	modload.LoaderState.ForceUseModules = true
-	modload.RootMode = modload.NeedRoot
+	modload.LoaderState.RootMode = modload.NeedRoot
 
 	goVersion := graphGo.String()
 	if goVersion != "" && gover.Compare(gover.Local(), goVersion) < 0 {
diff --git a/src/cmd/go/internal/modcmd/tidy.go b/src/cmd/go/internal/modcmd/tidy.go
index dde70c6d74181e..0314dcef250d81 100644
--- a/src/cmd/go/internal/modcmd/tidy.go
+++ b/src/cmd/go/internal/modcmd/tidy.go
@@ -120,7 +120,7 @@ func runTidy(ctx context.Context, cmd *base.Command, args []string) {
 	// that are in 'all' but outside of the main module, we must explicitly
 	// request that their test dependencies be included.
 	modload.LoaderState.ForceUseModules = true
-	modload.RootMode = modload.NeedRoot
+	modload.LoaderState.RootMode = modload.NeedRoot
 
 	goVersion := tidyGo.String()
 	if goVersion != "" && gover.Compare(gover.Local(), goVersion) < 0 {
diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index bd3d8d602e2382..dfea571c0e0317 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -78,7 +78,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 		base.Fatalf("go: 'go mod vendor' accepts no arguments")
 	}
 	modload.LoaderState.ForceUseModules = true
-	modload.RootMode = modload.NeedRoot
+	modload.LoaderState.RootMode = modload.NeedRoot
 
 	loadOpts := modload.PackageOpts{
 		Tags:                     imports.AnyTags(),
diff --git a/src/cmd/go/internal/modcmd/verify.go b/src/cmd/go/internal/modcmd/verify.go
index ecd25d3a40e610..157c920c067321 100644
--- a/src/cmd/go/internal/modcmd/verify.go
+++ b/src/cmd/go/internal/modcmd/verify.go
@@ -51,7 +51,7 @@ func runVerify(ctx context.Context, cmd *base.Command, args []string) {
 		base.Fatalf("go: verify takes no arguments")
 	}
 	modload.LoaderState.ForceUseModules = true
-	modload.RootMode = modload.NeedRoot
+	modload.LoaderState.RootMode = modload.NeedRoot
 
 	// Only verify up to GOMAXPROCS zips at once.
 	type token struct{}
diff --git a/src/cmd/go/internal/modcmd/why.go b/src/cmd/go/internal/modcmd/why.go
index 6c4bf8abab17ee..62a5387ed8841c 100644
--- a/src/cmd/go/internal/modcmd/why.go
+++ b/src/cmd/go/internal/modcmd/why.go
@@ -65,7 +65,7 @@ func init() {
 func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 	modload.InitWorkfile()
 	modload.LoaderState.ForceUseModules = true
-	modload.RootMode = modload.NeedRoot
+	modload.LoaderState.RootMode = modload.NeedRoot
 	modload.ExplicitWriteGoMod = true // don't write go.mod in ListModules
 
 	loadOpts := modload.PackageOpts{
diff --git a/src/cmd/go/internal/modload/import_test.go b/src/cmd/go/internal/modload/import_test.go
index eb4f5d64d3a3c7..f6b8bb90992735 100644
--- a/src/cmd/go/internal/modload/import_test.go
+++ b/src/cmd/go/internal/modload/import_test.go
@@ -60,13 +60,13 @@ func TestQueryImport(t *testing.T) {
 	testenv.MustHaveExecPath(t, "git")
 
 	oldAllowMissingModuleImports := allowMissingModuleImports
-	oldRootMode := RootMode
+	oldRootMode := LoaderState.RootMode
 	defer func() {
 		allowMissingModuleImports = oldAllowMissingModuleImports
-		RootMode = oldRootMode
+		LoaderState.RootMode = oldRootMode
 	}()
 	allowMissingModuleImports = true
-	RootMode = NoRoot
+	LoaderState.RootMode = NoRoot
 
 	ctx := context.Background()
 	rs := LoadModFile(ctx)
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 264c02ef6db100..58b16a6599dbe3 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -38,9 +38,6 @@ import (
 //
 // TODO(#40775): See if these can be plumbed as explicit parameters.
 var (
-	// RootMode determines whether a module root is needed.
-	RootMode Root
-
 	allowMissingModuleImports bool
 
 	// ExplicitWriteGoMod prevents LoadPackages, ListModules, and other functions
@@ -370,7 +367,7 @@ func InitWorkfile() {
 // It is exported mainly for Go toolchain switching, which must process
 // the go.work very early at startup.
 func FindGoWork(wd string) string {
-	if RootMode == NoRoot {
+	if LoaderState.RootMode == NoRoot {
 		return ""
 	}
 
@@ -403,7 +400,7 @@ func setState(s State) State {
 	oldState := State{
 		initialized:     LoaderState.initialized,
 		ForceUseModules: LoaderState.ForceUseModules,
-		rootMode:        RootMode,
+		RootMode:        LoaderState.RootMode,
 		modRoots:        modRoots,
 		modulesEnabled:  cfg.ModulesEnabled,
 		mainModules:     MainModules,
@@ -411,7 +408,7 @@ func setState(s State) State {
 	}
 	LoaderState.initialized = s.initialized
 	LoaderState.ForceUseModules = s.ForceUseModules
-	RootMode = s.rootMode
+	LoaderState.RootMode = s.RootMode
 	modRoots = s.modRoots
 	cfg.ModulesEnabled = s.modulesEnabled
 	MainModules = s.mainModules
@@ -430,13 +427,15 @@ type State struct {
 	// ForceUseModules may be set to force modules to be enabled when
 	// GO111MODULE=auto or to report an error when GO111MODULE=off.
 	ForceUseModules bool
-	rootMode        Root
-	modRoots        []string
-	modulesEnabled  bool
-	mainModules     *MainModuleSet
-	requirements    *Requirements
-	workFilePath    string
-	modfetchState   modfetch.State
+
+	// RootMode determines whether a module root is needed.
+	RootMode       Root
+	modRoots       []string
+	modulesEnabled bool
+	mainModules    *MainModuleSet
+	requirements   *Requirements
+	workFilePath   string
+	modfetchState  modfetch.State
 }
 
 func NewState() *State { return &State{} }
@@ -495,7 +494,7 @@ func Init() {
 	if modRoots != nil {
 		// modRoot set before Init was called ("go mod init" does this).
 		// No need to search for go.mod.
-	} else if RootMode == NoRoot {
+	} else if LoaderState.RootMode == NoRoot {
 		if cfg.ModFile != "" && !base.InGOFLAGS("-modfile") {
 			base.Fatalf("go: -modfile cannot be used with commands that ignore the current module")
 		}
@@ -510,7 +509,7 @@ func Init() {
 			if cfg.ModFile != "" {
 				base.Fatalf("go: cannot find main module, but -modfile was set.\n\t-modfile cannot be used to set the module root directory.")
 			}
-			if RootMode == NeedRoot {
+			if LoaderState.RootMode == NeedRoot {
 				base.Fatal(ErrNoModRoot)
 			}
 			if !mustUseModules {
@@ -525,7 +524,7 @@ func Init() {
 			// It's a bit of a peculiar thing to disallow but quite mysterious
 			// when it happens. See golang.org/issue/26708.
 			fmt.Fprintf(os.Stderr, "go: warning: ignoring go.mod in system temp root %v\n", os.TempDir())
-			if RootMode == NeedRoot {
+			if LoaderState.RootMode == NeedRoot {
 				base.Fatal(ErrNoModRoot)
 			}
 			if !mustUseModules {
@@ -547,7 +546,7 @@ func Init() {
 		gopath = list[0]
 		if _, err := fsys.Stat(filepath.Join(gopath, "go.mod")); err == nil {
 			fmt.Fprintf(os.Stderr, "go: warning: ignoring go.mod in $GOPATH %v\n", gopath)
-			if RootMode == NeedRoot {
+			if LoaderState.RootMode == NeedRoot {
 				base.Fatal(ErrNoModRoot)
 			}
 			if !mustUseModules {
diff --git a/src/cmd/go/internal/run/run.go b/src/cmd/go/internal/run/run.go
index 05ea5eaa15eea4..d922dcdd66a551 100644
--- a/src/cmd/go/internal/run/run.go
+++ b/src/cmd/go/internal/run/run.go
@@ -77,7 +77,7 @@ func runRun(ctx context.Context, cmd *base.Command, args []string) {
 		// before loading packages, since it affects package locations, e.g.,
 		// for -race and -msan.
 		modload.LoaderState.ForceUseModules = true
-		modload.RootMode = modload.NoRoot
+		modload.LoaderState.RootMode = modload.NoRoot
 		modload.AllowMissingModuleImports()
 		modload.Init()
 	} else {
diff --git a/src/cmd/go/internal/tool/tool.go b/src/cmd/go/internal/tool/tool.go
index 120ef5339bede0..ef25d17b54d892 100644
--- a/src/cmd/go/internal/tool/tool.go
+++ b/src/cmd/go/internal/tool/tool.go
@@ -308,7 +308,7 @@ func buildAndRunBuiltinTool(ctx context.Context, toolName, tool string, args []s
 	// Ignore go.mod and go.work: we don't need them, and we want to be able
 	// to run the tool even if there's an issue with the module or workspace the
 	// user happens to be in.
-	modload.RootMode = modload.NoRoot
+	modload.LoaderState.RootMode = modload.NoRoot
 
 	runFunc := func(b *work.Builder, ctx context.Context, a *work.Action) error {
 		cmdline := str.StringList(builtTool(a), a.Args)
diff --git a/src/cmd/go/internal/toolchain/select.go b/src/cmd/go/internal/toolchain/select.go
index 8f55076c6282c2..4f46b19c12167b 100644
--- a/src/cmd/go/internal/toolchain/select.go
+++ b/src/cmd/go/internal/toolchain/select.go
@@ -354,7 +354,7 @@ func Exec(gotoolchain string) {
 	// Set up modules without an explicit go.mod, to download distribution.
 	modload.Reset()
 	modload.LoaderState.ForceUseModules = true
-	modload.RootMode = modload.NoRoot
+	modload.LoaderState.RootMode = modload.NoRoot
 	modload.Init()
 
 	// Download and unpack toolchain module into module cache.
@@ -693,7 +693,7 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 
 	// Set up modules without an explicit go.mod, to download go.mod.
 	modload.LoaderState.ForceUseModules = true
-	modload.RootMode = modload.NoRoot
+	modload.LoaderState.RootMode = modload.NoRoot
 	modload.Init()
 	defer modload.Reset()
 
diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index 21bbab1bf47463..adc98f93138007 100644
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -860,7 +860,7 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
 // See golang.org/issue/40276 for details and rationale.
 func installOutsideModule(ctx context.Context, args []string) {
 	modload.LoaderState.ForceUseModules = true
-	modload.RootMode = modload.NoRoot
+	modload.LoaderState.RootMode = modload.NoRoot
 	modload.AllowMissingModuleImports()
 	modload.Init()
 	BuildInit()

From 11d5484190f80823c9b6312fd40f6491e864111b Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Tue, 7 Oct 2025 16:10:19 +0000
Subject: [PATCH 077/229] runtime: fix self-deadlock on sbrk platforms

The sbrk mem.go implementation doesn't enforce being called on the
systemstack, but it can call back into itself if there's a stack growth.
Because the sbrk implementation requires acquiring memlock, it can
self-deadlock.

For the most part the mem.go API is called on the system stack, but
there are cases where we call sysAlloc on the regular Go stack. This is
fine in general, except on sbrk platforms because of the aforementioned
deadlock.

This change, rather than adding a new invariant to mem.go, switches to
the systemstack in the mem.go API implementation for sbrk platforms.

Change-Id: Ie0f0ea80a8d7578cdeabc8252107e64a5e633856
Reviewed-on: https://go-review.googlesource.com/c/go/+/709775
Reviewed-by: Cherry Mui 
LUCI-TryBot-Result: Go LUCI 
---
 src/runtime/mem_sbrk.go | 158 ++++++++++++++++++++++++++--------------
 1 file changed, 103 insertions(+), 55 deletions(-)

diff --git a/src/runtime/mem_sbrk.go b/src/runtime/mem_sbrk.go
index 05f0fdb5d74ed6..5284bbd0009865 100644
--- a/src/runtime/mem_sbrk.go
+++ b/src/runtime/mem_sbrk.go
@@ -48,6 +48,16 @@ type memHdrPtr uintptr
 func (p memHdrPtr) ptr() *memHdr   { return (*memHdr)(unsafe.Pointer(p)) }
 func (p *memHdrPtr) set(x *memHdr) { *p = memHdrPtr(unsafe.Pointer(x)) }
 
+// memAlloc allocates n bytes from the brk reservation, or if it's full,
+// the system.
+//
+// memlock must be held.
+//
+// memAlloc must be called on the system stack, otherwise a stack growth
+// could cause us to call back into it. Since memlock is held, that could
+// lead to a self-deadlock.
+//
+//go:systemstack
 func memAlloc(n uintptr) unsafe.Pointer {
 	if p := memAllocNoGrow(n); p != nil {
 		return p
@@ -55,6 +65,15 @@ func memAlloc(n uintptr) unsafe.Pointer {
 	return sbrk(n)
 }
 
+// memAllocNoGrow attempts to allocate n bytes from the existing brk.
+//
+// memlock must be held.
+//
+// memAlloc must be called on the system stack, otherwise a stack growth
+// could cause us to call back into it. Since memlock is held, that could
+// lead to a self-deadlock.
+//
+//go:systemstack
 func memAllocNoGrow(n uintptr) unsafe.Pointer {
 	n = memRound(n)
 	var prevp *memHdr
@@ -78,6 +97,15 @@ func memAllocNoGrow(n uintptr) unsafe.Pointer {
 	return nil
 }
 
+// memFree makes [ap, ap+n) available for reallocation by memAlloc.
+//
+// memlock must be held.
+//
+// memAlloc must be called on the system stack, otherwise a stack growth
+// could cause us to call back into it. Since memlock is held, that could
+// lead to a self-deadlock.
+//
+//go:systemstack
 func memFree(ap unsafe.Pointer, n uintptr) {
 	n = memRound(n)
 	memclrNoHeapPointers(ap, n)
@@ -122,6 +150,15 @@ func memFree(ap unsafe.Pointer, n uintptr) {
 	}
 }
 
+// memCheck checks invariants around free list management.
+//
+// memlock must be held.
+//
+// memAlloc must be called on the system stack, otherwise a stack growth
+// could cause us to call back into it. Since memlock is held, that could
+// lead to a self-deadlock.
+//
+//go:systemstack
 func memCheck() {
 	if !memDebug {
 		return
@@ -158,26 +195,31 @@ func initBloc() {
 }
 
 func sysAllocOS(n uintptr, _ string) unsafe.Pointer {
-	lock(&memlock)
-	p := memAlloc(n)
-	memCheck()
-	unlock(&memlock)
-	return p
+	var p uintptr
+	systemstack(func() {
+		lock(&memlock)
+		p = uintptr(memAlloc(n))
+		memCheck()
+		unlock(&memlock)
+	})
+	return unsafe.Pointer(p)
 }
 
 func sysFreeOS(v unsafe.Pointer, n uintptr) {
-	lock(&memlock)
-	if uintptr(v)+n == bloc {
-		// Address range being freed is at the end of memory,
-		// so record a new lower value for end of memory.
-		// Can't actually shrink address space because segment is shared.
-		memclrNoHeapPointers(v, n)
-		bloc -= n
-	} else {
-		memFree(v, n)
-		memCheck()
-	}
-	unlock(&memlock)
+	systemstack(func() {
+		lock(&memlock)
+		if uintptr(v)+n == bloc {
+			// Address range being freed is at the end of memory,
+			// so record a new lower value for end of memory.
+			// Can't actually shrink address space because segment is shared.
+			memclrNoHeapPointers(v, n)
+			bloc -= n
+		} else {
+			memFree(v, n)
+			memCheck()
+		}
+		unlock(&memlock)
+	})
 }
 
 func sysUnusedOS(v unsafe.Pointer, n uintptr) {
@@ -202,49 +244,55 @@ func sysFaultOS(v unsafe.Pointer, n uintptr) {
 }
 
 func sysReserveOS(v unsafe.Pointer, n uintptr, _ string) unsafe.Pointer {
-	lock(&memlock)
-	var p unsafe.Pointer
-	if uintptr(v) == bloc {
-		// Address hint is the current end of memory,
-		// so try to extend the address space.
-		p = sbrk(n)
-	}
-	if p == nil && v == nil {
-		p = memAlloc(n)
-		memCheck()
-	}
-	unlock(&memlock)
-	return p
+	var p uintptr
+	systemstack(func() {
+		lock(&memlock)
+		if uintptr(v) == bloc {
+			// Address hint is the current end of memory,
+			// so try to extend the address space.
+			p = uintptr(sbrk(n))
+		}
+		if p == 0 && v == nil {
+			p = uintptr(memAlloc(n))
+			memCheck()
+		}
+		unlock(&memlock)
+	})
+	return unsafe.Pointer(p)
 }
 
 func sysReserveAlignedSbrk(size, align uintptr) (unsafe.Pointer, uintptr) {
-	lock(&memlock)
-	if p := memAllocNoGrow(size + align); p != nil {
-		// We can satisfy the reservation from the free list.
-		// Trim off the unaligned parts.
-		pAligned := alignUp(uintptr(p), align)
-		if startLen := pAligned - uintptr(p); startLen > 0 {
-			memFree(p, startLen)
+	var p uintptr
+	systemstack(func() {
+		lock(&memlock)
+		if base := memAllocNoGrow(size + align); base != nil {
+			// We can satisfy the reservation from the free list.
+			// Trim off the unaligned parts.
+			start := alignUp(uintptr(base), align)
+			if startLen := start - uintptr(base); startLen > 0 {
+				memFree(base, startLen)
+			}
+			end := start + size
+			if endLen := (uintptr(base) + size + align) - end; endLen > 0 {
+				memFree(unsafe.Pointer(end), endLen)
+			}
+			memCheck()
+			unlock(&memlock)
+			p = start
+			return
 		}
-		end := pAligned + size
-		if endLen := (uintptr(p) + size + align) - end; endLen > 0 {
-			memFree(unsafe.Pointer(end), endLen)
+
+		// Round up bloc to align, then allocate size.
+		p = alignUp(bloc, align)
+		r := sbrk(p + size - bloc)
+		if r == nil {
+			p, size = 0, 0
+		} else if l := p - uintptr(r); l > 0 {
+			// Free the area we skipped over for alignment.
+			memFree(r, l)
+			memCheck()
 		}
-		memCheck()
 		unlock(&memlock)
-		return unsafe.Pointer(pAligned), size
-	}
-
-	// Round up bloc to align, then allocate size.
-	p := alignUp(bloc, align)
-	r := sbrk(p + size - bloc)
-	if r == nil {
-		p, size = 0, 0
-	} else if l := p - uintptr(r); l > 0 {
-		// Free the area we skipped over for alignment.
-		memFree(r, l)
-		memCheck()
-	}
-	unlock(&memlock)
+	})
 	return unsafe.Pointer(p), size
 }

From 6f7926589d03180863aa05cbb55a9d9c63e76b99 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 19:44:11 -0400
Subject: [PATCH 078/229] cmd/go: refactor usage of `modRoots`

This commit refactors usage of the global variable `modRoots` to the
global LoaderState field of the same name.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf 'ex { modRoots -> LoaderState.modRoots }'
rf 'add State.RootMode \
// These are primarily used to initialize the MainModules, and should\
// be eventually superseded by them but are still used in cases where\
// the module roots are required but MainModules has not been\
// initialized yet. Set to the modRoots of the main modules.\
// modRoots != nil implies len(modRoots) > 0'
rf 'rm modRoots'

Change-Id: Ie9e1f3d468cfceee25efefaf945b10492318b079
Reviewed-on: https://go-review.googlesource.com/c/go/+/698059
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/modload/init.go  | 61 ++++++++++++++--------------
 src/cmd/go/internal/modload/load.go  |  2 +-
 src/cmd/go/internal/modload/query.go |  2 +-
 3 files changed, 32 insertions(+), 33 deletions(-)

diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 58b16a6599dbe3..dc0d78499b9cd0 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -53,14 +53,7 @@ var (
 
 // Variables set in Init.
 var (
-
-	// These are primarily used to initialize the MainModules, and should be
-	// eventually superseded by them but are still used in cases where the module
-	// roots are required but MainModules hasn't been initialized yet. Set to
-	// the modRoots of the main modules.
-	// modRoots != nil implies len(modRoots) > 0
-	modRoots []string
-	gopath   string
+	gopath string
 )
 
 // EnterModule resets MainModules and requirements to refer to just this one module.
@@ -70,7 +63,7 @@ func EnterModule(ctx context.Context, enterModroot string) {
 	workFilePath = "" // Force module mode
 	modfetch.Reset()
 
-	modRoots = []string{enterModroot}
+	LoaderState.modRoots = []string{enterModroot}
 	LoadModFile(ctx)
 }
 
@@ -401,7 +394,7 @@ func setState(s State) State {
 		initialized:     LoaderState.initialized,
 		ForceUseModules: LoaderState.ForceUseModules,
 		RootMode:        LoaderState.RootMode,
-		modRoots:        modRoots,
+		modRoots:        LoaderState.modRoots,
 		modulesEnabled:  cfg.ModulesEnabled,
 		mainModules:     MainModules,
 		requirements:    requirements,
@@ -409,7 +402,7 @@ func setState(s State) State {
 	LoaderState.initialized = s.initialized
 	LoaderState.ForceUseModules = s.ForceUseModules
 	LoaderState.RootMode = s.RootMode
-	modRoots = s.modRoots
+	LoaderState.modRoots = s.modRoots
 	cfg.ModulesEnabled = s.modulesEnabled
 	MainModules = s.mainModules
 	requirements = s.requirements
@@ -429,7 +422,13 @@ type State struct {
 	ForceUseModules bool
 
 	// RootMode determines whether a module root is needed.
-	RootMode       Root
+	RootMode Root
+
+	// These are primarily used to initialize the MainModules, and should
+	// be eventually superseded by them but are still used in cases where
+	// the module roots are required but MainModules has not been
+	// initialized yet. Set to the modRoots of the main modules.
+	// modRoots != nil implies len(modRoots) > 0
 	modRoots       []string
 	modulesEnabled bool
 	mainModules    *MainModuleSet
@@ -491,14 +490,14 @@ func Init() {
 	if os.Getenv("GCM_INTERACTIVE") == "" {
 		os.Setenv("GCM_INTERACTIVE", "never")
 	}
-	if modRoots != nil {
+	if LoaderState.modRoots != nil {
 		// modRoot set before Init was called ("go mod init" does this).
 		// No need to search for go.mod.
 	} else if LoaderState.RootMode == NoRoot {
 		if cfg.ModFile != "" && !base.InGOFLAGS("-modfile") {
 			base.Fatalf("go: -modfile cannot be used with commands that ignore the current module")
 		}
-		modRoots = nil
+		LoaderState.modRoots = nil
 	} else if workFilePath != "" {
 		// We're in workspace mode, which implies module mode.
 		if cfg.ModFile != "" {
@@ -531,7 +530,7 @@ func Init() {
 				return
 			}
 		} else {
-			modRoots = []string{modRoot}
+			LoaderState.modRoots = []string{modRoot}
 		}
 	}
 	if cfg.ModFile != "" && !strings.HasSuffix(cfg.ModFile, ".mod") {
@@ -566,7 +565,7 @@ func Init() {
 // be called until the command is installed and flags are parsed. Instead of
 // calling Init and Enabled, the main package can call this function.
 func WillBeEnabled() bool {
-	if modRoots != nil || cfg.ModulesEnabled {
+	if LoaderState.modRoots != nil || cfg.ModulesEnabled {
 		// Already enabled.
 		return true
 	}
@@ -619,7 +618,7 @@ func FindGoMod(wd string) string {
 // (usually through MustModRoot).
 func Enabled() bool {
 	Init()
-	return modRoots != nil || cfg.ModulesEnabled
+	return LoaderState.modRoots != nil || cfg.ModulesEnabled
 }
 
 func VendorDir() string {
@@ -651,7 +650,7 @@ func inWorkspaceMode() bool {
 // does not require a main module.
 func HasModRoot() bool {
 	Init()
-	return modRoots != nil
+	return LoaderState.modRoots != nil
 }
 
 // MustHaveModRoot checks that a main module or main modules are present,
@@ -880,16 +879,16 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 	var workFile *modfile.WorkFile
 	if inWorkspaceMode() {
 		var err error
-		workFile, modRoots, err = LoadWorkFile(workFilePath)
+		workFile, LoaderState.modRoots, err = LoadWorkFile(workFilePath)
 		if err != nil {
 			return nil, err
 		}
-		for _, modRoot := range modRoots {
+		for _, modRoot := range LoaderState.modRoots {
 			sumFile := strings.TrimSuffix(modFilePath(modRoot), ".mod") + ".sum"
 			modfetch.WorkspaceGoSumFiles = append(modfetch.WorkspaceGoSumFiles, sumFile)
 		}
 		modfetch.GoSumFile = workFilePath + ".sum"
-	} else if len(modRoots) == 0 {
+	} else if len(LoaderState.modRoots) == 0 {
 		// We're in module mode, but not inside a module.
 		//
 		// Commands like 'go build', 'go run', 'go list' have no go.mod file to
@@ -908,9 +907,9 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		//
 		// See golang.org/issue/32027.
 	} else {
-		modfetch.GoSumFile = strings.TrimSuffix(modFilePath(modRoots[0]), ".mod") + ".sum"
+		modfetch.GoSumFile = strings.TrimSuffix(modFilePath(LoaderState.modRoots[0]), ".mod") + ".sum"
 	}
-	if len(modRoots) == 0 {
+	if len(LoaderState.modRoots) == 0 {
 		// TODO(#49228): Instead of creating a fake module with an empty modroot,
 		// make MainModules.Len() == 0 mean that we're in module mode but not inside
 		// any module.
@@ -956,7 +955,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 	var mainModules []module.Version
 	var indices []*modFileIndex
 	var errs []error
-	for _, modroot := range modRoots {
+	for _, modroot := range LoaderState.modRoots {
 		gomod := modFilePath(modroot)
 		var fixed bool
 		data, f, err := ReadModFile(gomod, fixVersion(ctx, &fixed))
@@ -1017,7 +1016,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		return nil, errors.Join(errs...)
 	}
 
-	MainModules = makeMainModules(mainModules, modRoots, modFiles, indices, workFile)
+	MainModules = makeMainModules(mainModules, LoaderState.modRoots, modFiles, indices, workFile)
 	setDefaultBuildMod() // possibly enable automatic vendoring
 	rs := requirementsFromModFiles(ctx, workFile, modFiles, opts)
 
@@ -1120,7 +1119,7 @@ func CheckReservedModulePath(path string) error {
 // packages at multiple versions from the same module).
 func CreateModFile(ctx context.Context, modPath string) {
 	modRoot := base.Cwd()
-	modRoots = []string{modRoot}
+	LoaderState.modRoots = []string{modRoot}
 	Init()
 	modFilePath := modFilePath(modRoot)
 	if _, err := fsys.Stat(modFilePath); err == nil {
@@ -1509,7 +1508,7 @@ func setDefaultBuildMod() {
 		cfg.BuildMod = "readonly"
 		return
 	}
-	if modRoots == nil {
+	if LoaderState.modRoots == nil {
 		if allowMissingModuleImports {
 			cfg.BuildMod = "mod"
 		} else {
@@ -1518,7 +1517,7 @@ func setDefaultBuildMod() {
 		return
 	}
 
-	if len(modRoots) >= 1 {
+	if len(LoaderState.modRoots) >= 1 {
 		var goVersion string
 		var versionSource string
 		if inWorkspaceMode() {
@@ -1537,10 +1536,10 @@ func setDefaultBuildMod() {
 		if workFilePath != "" {
 			vendorDir = filepath.Join(filepath.Dir(workFilePath), "vendor")
 		} else {
-			if len(modRoots) != 1 {
-				panic(fmt.Errorf("outside workspace mode, but have %v modRoots", modRoots))
+			if len(LoaderState.modRoots) != 1 {
+				panic(fmt.Errorf("outside workspace mode, but have %v modRoots", LoaderState.modRoots))
 			}
-			vendorDir = filepath.Join(modRoots[0], "vendor")
+			vendorDir = filepath.Join(LoaderState.modRoots[0], "vendor")
 		}
 		if fi, err := fsys.Stat(vendorDir); err == nil && fi.IsDir() {
 			if goVersion != "" {
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index 8b2be3b300e9e1..7fba712f952e2a 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -271,7 +271,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 			case m.IsLocal():
 				// Evaluate list of file system directories on first iteration.
 				if m.Dirs == nil {
-					matchModRoots := modRoots
+					matchModRoots := LoaderState.modRoots
 					if opts.MainModule != (module.Version{}) {
 						matchModRoots = []string{MainModules.ModRoot(opts.MainModule)}
 					}
diff --git a/src/cmd/go/internal/modload/query.go b/src/cmd/go/internal/modload/query.go
index c4cf55442ba69b..65934b0d69e517 100644
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@@ -716,7 +716,7 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 
 	var mainModuleMatches []module.Version
 	for _, mainModule := range MainModules.Versions() {
-		m := match(mainModule, modRoots, true)
+		m := match(mainModule, LoaderState.modRoots, true)
 		if len(m.Pkgs) > 0 {
 			if query != "upgrade" && query != "patch" {
 				return nil, nil, &QueryMatchesPackagesInMainModuleError{

From 6e4007e8cffbb870e6b606307ab7308236ecefb9 Mon Sep 17 00:00:00 2001
From: Neal Patel 
Date: Thu, 11 Sep 2025 16:27:04 -0400
Subject: [PATCH 079/229] crypto/x509: mitigate DoS vector when intermediate
 certificate contains DSA public key

An attacker could craft an intermediate X.509 certificate
containing a DSA public key and can crash a remote host
with an unauthenticated call to any endpoint that
verifies the certificate chain.

Thank you to Jakub Ciolek for reporting this issue.

Fixes CVE-2025-58188
Fixes #75675

Change-Id: I2ecbb87b9b8268dbc55c8795891e596ab60f0088
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2780
Reviewed-by: Damien Neil 
Reviewed-by: Roland Shoemaker 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709853
Reviewed-by: Carlos Amedee 
Auto-Submit: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
---
 src/crypto/x509/verify.go      |   5 +-
 src/crypto/x509/verify_test.go | 127 +++++++++++++++++++++++++++++++++
 2 files changed, 131 insertions(+), 1 deletion(-)

diff --git a/src/crypto/x509/verify.go b/src/crypto/x509/verify.go
index 7cc0fb2e3e0385..755c1db96c1edb 100644
--- a/src/crypto/x509/verify.go
+++ b/src/crypto/x509/verify.go
@@ -927,7 +927,10 @@ func alreadyInChain(candidate *Certificate, chain []*Certificate) bool {
 		if !bytes.Equal(candidate.RawSubject, cert.RawSubject) {
 			continue
 		}
-		if !candidate.PublicKey.(pubKeyEqual).Equal(cert.PublicKey) {
+		// We enforce the canonical encoding of SPKI (by only allowing the
+		// correct AI paremeter encodings in parseCertificate), so it's safe to
+		// directly compare the raw bytes.
+		if !bytes.Equal(candidate.RawSubjectPublicKeyInfo, cert.RawSubjectPublicKeyInfo) {
 			continue
 		}
 		var certSAN *pkix.Extension
diff --git a/src/crypto/x509/verify_test.go b/src/crypto/x509/verify_test.go
index 7991f49946d587..5595f99ea5e43a 100644
--- a/src/crypto/x509/verify_test.go
+++ b/src/crypto/x509/verify_test.go
@@ -6,6 +6,7 @@ package x509
 
 import (
 	"crypto"
+	"crypto/dsa"
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rand"
@@ -3048,3 +3049,129 @@ func TestInvalidPolicyWithAnyKeyUsage(t *testing.T) {
 		t.Fatalf("unexpected error, got %q, want %q", err, expectedErr)
 	}
 }
+
+func TestCertificateChainSignedByECDSA(t *testing.T) {
+	caKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	root := &Certificate{
+		SerialNumber:          big.NewInt(1),
+		Subject:               pkix.Name{CommonName: "X"},
+		NotBefore:             time.Now().Add(-time.Hour),
+		NotAfter:              time.Now().Add(365 * 24 * time.Hour),
+		IsCA:                  true,
+		KeyUsage:              KeyUsageCertSign | KeyUsageCRLSign,
+		BasicConstraintsValid: true,
+	}
+	caDER, err := CreateCertificate(rand.Reader, root, root, &caKey.PublicKey, caKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	root, err = ParseCertificate(caDER)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	leafKey, _ := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	leaf := &Certificate{
+		SerialNumber:          big.NewInt(42),
+		Subject:               pkix.Name{CommonName: "leaf"},
+		NotBefore:             time.Now().Add(-10 * time.Minute),
+		NotAfter:              time.Now().Add(24 * time.Hour),
+		KeyUsage:              KeyUsageDigitalSignature,
+		ExtKeyUsage:           []ExtKeyUsage{ExtKeyUsageServerAuth},
+		BasicConstraintsValid: true,
+	}
+	leafDER, err := CreateCertificate(rand.Reader, leaf, root, &leafKey.PublicKey, caKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	leaf, err = ParseCertificate(leafDER)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	inter, err := ParseCertificate(dsaSelfSignedCNX(t))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	inters := NewCertPool()
+	inters.AddCert(root)
+	inters.AddCert(inter)
+
+	wantErr := "certificate signed by unknown authority"
+	_, err = leaf.Verify(VerifyOptions{Intermediates: inters, Roots: NewCertPool()})
+	if !strings.Contains(err.Error(), wantErr) {
+		t.Errorf("got %v, want %q", err, wantErr)
+	}
+}
+
+// dsaSelfSignedCNX produces DER-encoded
+// certificate with the properties:
+//
+//	Subject=Issuer=CN=X
+//	DSA SPKI
+//	Matching inner/outer signature OIDs
+//	Dummy ECDSA signature
+func dsaSelfSignedCNX(t *testing.T) []byte {
+	t.Helper()
+	var params dsa.Parameters
+	if err := dsa.GenerateParameters(¶ms, rand.Reader, dsa.L1024N160); err != nil {
+		t.Fatal(err)
+	}
+
+	var dsaPriv dsa.PrivateKey
+	dsaPriv.Parameters = params
+	if err := dsa.GenerateKey(&dsaPriv, rand.Reader); err != nil {
+		t.Fatal(err)
+	}
+	dsaPub := &dsaPriv.PublicKey
+
+	type dsaParams struct{ P, Q, G *big.Int }
+	paramDER, err := asn1.Marshal(dsaParams{dsaPub.P, dsaPub.Q, dsaPub.G})
+	if err != nil {
+		t.Fatal(err)
+	}
+	yDER, err := asn1.Marshal(dsaPub.Y)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	spki := publicKeyInfo{
+		Algorithm: pkix.AlgorithmIdentifier{
+			Algorithm:  oidPublicKeyDSA,
+			Parameters: asn1.RawValue{FullBytes: paramDER},
+		},
+		PublicKey: asn1.BitString{Bytes: yDER, BitLength: 8 * len(yDER)},
+	}
+
+	rdn := pkix.Name{CommonName: "X"}.ToRDNSequence()
+	b, err := asn1.Marshal(rdn)
+	if err != nil {
+		t.Fatal(err)
+	}
+	rawName := asn1.RawValue{FullBytes: b}
+
+	algoIdent := pkix.AlgorithmIdentifier{Algorithm: oidSignatureDSAWithSHA256}
+	tbs := tbsCertificate{
+		Version:            0,
+		SerialNumber:       big.NewInt(1002),
+		SignatureAlgorithm: algoIdent,
+		Issuer:             rawName,
+		Validity:           validity{NotBefore: time.Now().Add(-time.Hour), NotAfter: time.Now().Add(24 * time.Hour)},
+		Subject:            rawName,
+		PublicKey:          spki,
+	}
+	c := certificate{
+		TBSCertificate:     tbs,
+		SignatureAlgorithm: algoIdent,
+		SignatureValue:     asn1.BitString{Bytes: []byte{0}, BitLength: 8},
+	}
+	dsaDER, err := asn1.Marshal(c)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return dsaDER
+}

From 3fc4c79fdbb17b9b29ea9f8c29dd780df075d4c4 Mon Sep 17 00:00:00 2001
From: Neal Patel 
Date: Mon, 15 Sep 2025 16:31:22 -0400
Subject: [PATCH 080/229] crypto/x509: improve domain name verification

Don't use domainToReverseLabels to check if domain names are valid,
since it is not particularly performant, and can contribute to DoS
vectors. Instead just iterate over the name and enforce the properties
we care about.

This also enforces that DNS names, both in SANs and name constraints,
are valid. We previously allowed invalid SANs, because some
intermediates had these weird names (see #23995), but there are
currently no trusted intermediates that have this property, and since we
target the web PKI, supporting this particular case is not a high
priority.

Thank you to Jakub Ciolek for reporting this issue.

Fixes CVE-2025-58187
Fixes #75681

Change-Id: I6ebce847dcbe5fc63ef2f9a74f53f11c4c56d3d1
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2820
Reviewed-by: Damien Neil 
Reviewed-by: Roland Shoemaker 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709854
Auto-Submit: Michael Pratt 
Reviewed-by: Carlos Amedee 
LUCI-TryBot-Result: Go LUCI 
---
 src/crypto/x509/name_constraints_test.go | 75 ++---------------------
 src/crypto/x509/parser.go                | 77 ++++++++++++++----------
 src/crypto/x509/parser_test.go           | 43 +++++++++++++
 src/crypto/x509/verify.go                |  1 +
 4 files changed, 96 insertions(+), 100 deletions(-)

diff --git a/src/crypto/x509/name_constraints_test.go b/src/crypto/x509/name_constraints_test.go
index a5851845164d10..831fcbc8d2eb82 100644
--- a/src/crypto/x509/name_constraints_test.go
+++ b/src/crypto/x509/name_constraints_test.go
@@ -1456,63 +1456,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		expectedError: "incompatible key usage",
 	},
 
-	// An invalid DNS SAN should be detected only at validation time so
-	// that we can process CA certificates in the wild that have invalid SANs.
-	// See https://github.com/golang/go/issues/23995
-
-	// #77: an invalid DNS or mail SAN will not be detected if name constraint
-	// checking is not triggered.
-	{
-		roots: make([]constraintsSpec, 1),
-		intermediates: [][]constraintsSpec{
-			{
-				{},
-			},
-		},
-		leaf: leafSpec{
-			sans: []string{"dns:this is invalid", "email:this @ is invalid"},
-		},
-	},
-
-	// #78: an invalid DNS SAN will be detected if any name constraint checking
-	// is triggered.
-	{
-		roots: []constraintsSpec{
-			{
-				bad: []string{"uri:"},
-			},
-		},
-		intermediates: [][]constraintsSpec{
-			{
-				{},
-			},
-		},
-		leaf: leafSpec{
-			sans: []string{"dns:this is invalid"},
-		},
-		expectedError: "cannot parse dnsName",
-	},
-
-	// #79: an invalid email SAN will be detected if any name constraint
-	// checking is triggered.
-	{
-		roots: []constraintsSpec{
-			{
-				bad: []string{"uri:"},
-			},
-		},
-		intermediates: [][]constraintsSpec{
-			{
-				{},
-			},
-		},
-		leaf: leafSpec{
-			sans: []string{"email:this @ is invalid"},
-		},
-		expectedError: "cannot parse rfc822Name",
-	},
-
-	// #80: if several EKUs are requested, satisfying any of them is sufficient.
+	// #77: if several EKUs are requested, satisfying any of them is sufficient.
 	{
 		roots: make([]constraintsSpec, 1),
 		intermediates: [][]constraintsSpec{
@@ -1527,7 +1471,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		requestedEKUs: []ExtKeyUsage{ExtKeyUsageClientAuth, ExtKeyUsageEmailProtection},
 	},
 
-	// #81: EKUs that are not asserted in VerifyOpts are not required to be
+	// #78: EKUs that are not asserted in VerifyOpts are not required to be
 	// nested.
 	{
 		roots: make([]constraintsSpec, 1),
@@ -1546,7 +1490,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		},
 	},
 
-	// #82: a certificate without SANs and CN is accepted in a constrained chain.
+	// #79: a certificate without SANs and CN is accepted in a constrained chain.
 	{
 		roots: []constraintsSpec{
 			{
@@ -1563,7 +1507,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		},
 	},
 
-	// #83: a certificate without SANs and with a CN that does not parse as a
+	// #80: a certificate without SANs and with a CN that does not parse as a
 	// hostname is accepted in a constrained chain.
 	{
 		roots: []constraintsSpec{
@@ -1582,7 +1526,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		},
 	},
 
-	// #84: a certificate with SANs and CN is accepted in a constrained chain.
+	// #81: a certificate with SANs and CN is accepted in a constrained chain.
 	{
 		roots: []constraintsSpec{
 			{
@@ -1600,14 +1544,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		},
 	},
 
-	// #85: .example.com is an invalid DNS name, it should not match the
-	// constraint example.com.
-	{
-		roots:         []constraintsSpec{{ok: []string{"dns:example.com"}}},
-		leaf:          leafSpec{sans: []string{"dns:.example.com"}},
-		expectedError: "cannot parse dnsName \".example.com\"",
-	},
-	// #86: URIs with IPv6 addresses with zones and ports are rejected
+	// #82: URIs with IPv6 addresses with zones and ports are rejected
 	{
 		roots: []constraintsSpec{
 			{
diff --git a/src/crypto/x509/parser.go b/src/crypto/x509/parser.go
index 4abcc1b7b590e2..9d6bfd6e95f949 100644
--- a/src/crypto/x509/parser.go
+++ b/src/crypto/x509/parser.go
@@ -413,10 +413,14 @@ func parseSANExtension(der cryptobyte.String) (dnsNames, emailAddresses []string
 			if err := isIA5String(email); err != nil {
 				return errors.New("x509: SAN rfc822Name is malformed")
 			}
+			parsed, ok := parseRFC2821Mailbox(email)
+			if !ok || (ok && !domainNameValid(parsed.domain, false)) {
+				return errors.New("x509: SAN rfc822Name is malformed")
+			}
 			emailAddresses = append(emailAddresses, email)
 		case nameTypeDNS:
 			name := string(data)
-			if err := isIA5String(name); err != nil {
+			if err := isIA5String(name); err != nil || (err == nil && !domainNameValid(name, false)) {
 				return errors.New("x509: SAN dNSName is malformed")
 			}
 			dnsNames = append(dnsNames, string(name))
@@ -426,14 +430,9 @@ func parseSANExtension(der cryptobyte.String) (dnsNames, emailAddresses []string
 				return errors.New("x509: SAN uniformResourceIdentifier is malformed")
 			}
 			uri, err := url.Parse(uriStr)
-			if err != nil {
+			if err != nil || (err == nil && uri.Host != "" && !domainNameValid(uri.Host, false)) {
 				return fmt.Errorf("x509: cannot parse URI %q: %s", uriStr, err)
 			}
-			if len(uri.Host) > 0 {
-				if _, ok := domainToReverseLabels(uri.Host); !ok {
-					return fmt.Errorf("x509: cannot parse URI %q: invalid domain", uriStr)
-				}
-			}
 			uris = append(uris, uri)
 		case nameTypeIP:
 			switch len(data) {
@@ -598,15 +597,7 @@ func parseNameConstraintsExtension(out *Certificate, e pkix.Extension) (unhandle
 					return nil, nil, nil, nil, errors.New("x509: invalid constraint value: " + err.Error())
 				}
 
-				trimmedDomain := domain
-				if len(trimmedDomain) > 0 && trimmedDomain[0] == '.' {
-					// constraints can have a leading
-					// period to exclude the domain
-					// itself, but that's not valid in a
-					// normal domain name.
-					trimmedDomain = trimmedDomain[1:]
-				}
-				if _, ok := domainToReverseLabels(trimmedDomain); !ok {
+				if !domainNameValid(domain, true) {
 					return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse dnsName constraint %q", domain)
 				}
 				dnsNames = append(dnsNames, domain)
@@ -647,12 +638,7 @@ func parseNameConstraintsExtension(out *Certificate, e pkix.Extension) (unhandle
 						return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse rfc822Name constraint %q", constraint)
 					}
 				} else {
-					// Otherwise it's a domain name.
-					domain := constraint
-					if len(domain) > 0 && domain[0] == '.' {
-						domain = domain[1:]
-					}
-					if _, ok := domainToReverseLabels(domain); !ok {
+					if !domainNameValid(constraint, true) {
 						return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse rfc822Name constraint %q", constraint)
 					}
 				}
@@ -668,15 +654,7 @@ func parseNameConstraintsExtension(out *Certificate, e pkix.Extension) (unhandle
 					return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse URI constraint %q: cannot be IP address", domain)
 				}
 
-				trimmedDomain := domain
-				if len(trimmedDomain) > 0 && trimmedDomain[0] == '.' {
-					// constraints can have a leading
-					// period to exclude the domain itself,
-					// but that's not valid in a normal
-					// domain name.
-					trimmedDomain = trimmedDomain[1:]
-				}
-				if _, ok := domainToReverseLabels(trimmedDomain); !ok {
+				if !domainNameValid(domain, true) {
 					return nil, nil, nil, nil, fmt.Errorf("x509: failed to parse URI constraint %q", domain)
 				}
 				uriDomains = append(uriDomains, domain)
@@ -1317,3 +1295,40 @@ func ParseRevocationList(der []byte) (*RevocationList, error) {
 
 	return rl, nil
 }
+
+// domainNameValid does minimal domain name validity checking. In particular it
+// enforces the following properties:
+//   - names cannot have the trailing period
+//   - names can only have a leading period if constraint is true
+//   - names must be <= 253 characters
+//   - names cannot have empty labels
+//   - names cannot labels that are longer than 63 characters
+//
+// Note that this does not enforce the LDH requirements for domain names.
+func domainNameValid(s string, constraint bool) bool {
+	if len(s) == 0 && constraint {
+		return true
+	}
+	if len(s) == 0 || (!constraint && s[0] == '.') || s[len(s)-1] == '.' || len(s) > 253 {
+		return false
+	}
+	lastDot := -1
+	if constraint && s[0] == '.' {
+		s = s[1:]
+	}
+
+	for i := 0; i <= len(s); i++ {
+		if i == len(s) || s[i] == '.' {
+			labelLen := i
+			if lastDot >= 0 {
+				labelLen -= lastDot + 1
+			}
+			if labelLen == 0 || labelLen > 63 {
+				return false
+			}
+			lastDot = i
+		}
+	}
+
+	return true
+}
diff --git a/src/crypto/x509/parser_test.go b/src/crypto/x509/parser_test.go
index 3b9d9aed826b01..1b553e362e48a0 100644
--- a/src/crypto/x509/parser_test.go
+++ b/src/crypto/x509/parser_test.go
@@ -8,6 +8,7 @@ import (
 	"encoding/asn1"
 	"encoding/pem"
 	"os"
+	"strings"
 	"testing"
 
 	cryptobyte_asn1 "golang.org/x/crypto/cryptobyte/asn1"
@@ -251,3 +252,45 @@ d5l1tRhScKu2NBgm74nYmJxJYgvuTA38wGhRrGU=
 		}
 	}
 }
+
+func TestDomainNameValid(t *testing.T) {
+	for _, tc := range []struct {
+		name       string
+		dnsName    string
+		constraint bool
+		valid      bool
+	}{
+		{"empty name, name", "", false, false},
+		{"empty name, constraint", "", true, true},
+		{"empty label, name", "a..a", false, false},
+		{"empty label, constraint", "a..a", true, false},
+		{"period, name", ".", false, false},
+		{"period, constraint", ".", true, false}, // TODO(roland): not entirely clear if this is a valid constraint (require at least one label?)
+		{"valid, name", "a.b.c", false, true},
+		{"valid, constraint", "a.b.c", true, true},
+		{"leading period, name", ".a.b.c", false, false},
+		{"leading period, constraint", ".a.b.c", true, true},
+		{"trailing period, name", "a.", false, false},
+		{"trailing period, constraint", "a.", true, false},
+		{"bare label, name", "a", false, true},
+		{"bare label, constraint", "a", true, true},
+		{"254 char label, name", strings.Repeat("a.a", 84) + "aaa", false, false},
+		{"254 char label, constraint", strings.Repeat("a.a", 84) + "aaa", true, false},
+		{"253 char label, name", strings.Repeat("a.a", 84) + "aa", false, false},
+		{"253 char label, constraint", strings.Repeat("a.a", 84) + "aa", true, false},
+		{"64 char single label, name", strings.Repeat("a", 64), false, false},
+		{"64 char single label, constraint", strings.Repeat("a", 64), true, false},
+		{"63 char single label, name", strings.Repeat("a", 63), false, true},
+		{"63 char single label, constraint", strings.Repeat("a", 63), true, true},
+		{"64 char label, name", "a." + strings.Repeat("a", 64), false, false},
+		{"64 char label, constraint", "a." + strings.Repeat("a", 64), true, false},
+		{"63 char label, name", "a." + strings.Repeat("a", 63), false, true},
+		{"63 char label, constraint", "a." + strings.Repeat("a", 63), true, true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			if tc.valid != domainNameValid(tc.dnsName, tc.constraint) {
+				t.Errorf("domainNameValid(%q, %t) = %v; want %v", tc.dnsName, tc.constraint, !tc.valid, tc.valid)
+			}
+		})
+	}
+}
diff --git a/src/crypto/x509/verify.go b/src/crypto/x509/verify.go
index 755c1db96c1edb..058153fbe73461 100644
--- a/src/crypto/x509/verify.go
+++ b/src/crypto/x509/verify.go
@@ -391,6 +391,7 @@ func parseRFC2821Mailbox(in string) (mailbox rfc2821Mailbox, ok bool) {
 // domainToReverseLabels converts a textual domain name like foo.example.com to
 // the list of labels in reverse order, e.g. ["com", "example", "foo"].
 func domainToReverseLabels(domain string) (reverseLabels []string, ok bool) {
+	reverseLabels = make([]string, 0, strings.Count(domain, ".")+1)
 	for len(domain) > 0 {
 		if i := strings.LastIndexByte(domain, '.'); i == -1 {
 			reverseLabels = append(reverseLabels, domain)

From 9b9d02c5a015910ce57024788de2ff254c6cfca6 Mon Sep 17 00:00:00 2001
From: Nicholas Husin 
Date: Tue, 30 Sep 2025 14:02:38 -0400
Subject: [PATCH 081/229] net/http: add httpcookiemaxnum GODEBUG option to
 limit number of cookies parsed

When handling HTTP headers, net/http does not currently limit the number
of cookies that can be parsed. The only limitation that exists is for
the size of the entire HTTP header, which is controlled by
MaxHeaderBytes (defaults to 1 MB).

Unfortunately, this allows a malicious actor to send HTTP headers which
contain a massive amount of small cookies, such that as much cookies as
possible can be fitted within the MaxHeaderBytes limitation. Internally,
this causes us to allocate a massive number of Cookie struct.

For example, a 1 MB HTTP header with cookies that repeats "a=;" will
cause an allocation of ~66 MB in the heap. This can serve as a way for
malicious actors to induce memory exhaustion.

To fix this, we will now limit the number of cookies we are willing to
parse to 3000 by default. This behavior can be changed by setting a new
GODEBUG option: GODEBUG=httpcookiemaxnum. httpcookiemaxnum can be set to
allow a higher or lower cookie limit. Setting it to 0 will also allow an
infinite number of cookies to be parsed.

Thanks to jub0bs for reporting this issue.

For #75672
Fixes CVE-2025-58186

Change-Id: Ied58b3bc8acf5d11c880f881f36ecbf1d5d52622
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2720
Reviewed-by: Roland Shoemaker 
Reviewed-by: Damien Neil 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709855
Reviewed-by: Carlos Amedee 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Michael Pratt 
---
 doc/godebug.md                 |  10 ++
 src/internal/godebugs/table.go |   1 +
 src/net/http/cookie.go         |  59 +++++++++-
 src/net/http/cookie_test.go    | 206 ++++++++++++++++++++++-----------
 src/runtime/metrics/doc.go     |   5 +
 5 files changed, 206 insertions(+), 75 deletions(-)

diff --git a/doc/godebug.md b/doc/godebug.md
index aaa0f9dd55e570..c12ce5311d90d1 100644
--- a/doc/godebug.md
+++ b/doc/godebug.md
@@ -153,6 +153,16 @@ for example,
 see the [runtime documentation](/pkg/runtime#hdr-Environment_Variables)
 and the [go command documentation](/cmd/go#hdr-Build_and_test_caching).
 
+### Go 1.26
+
+Go 1.26 added a new `httpcookiemaxnum` setting that controls the maximum number
+of cookies that net/http will accept when parsing HTTP headers. If the number of
+cookie in a header exceeds the number set in `httpcookiemaxnum`, cookie parsing
+will fail early. The default value is `httpcookiemaxnum=3000`. Setting
+`httpcookiemaxnum=0` will allow the cookie parsing to accept an indefinite
+number of cookies. To avoid denial of service attacks, this setting and default
+was backported to Go 1.25.2 and Go 1.24.8.
+
 ### Go 1.25
 
 Go 1.25 added a new `decoratemappings` setting that controls whether the Go
diff --git a/src/internal/godebugs/table.go b/src/internal/godebugs/table.go
index 2d008825459bb2..852305e8553aab 100644
--- a/src/internal/godebugs/table.go
+++ b/src/internal/godebugs/table.go
@@ -42,6 +42,7 @@ var All = []Info{
 	{Name: "http2client", Package: "net/http"},
 	{Name: "http2debug", Package: "net/http", Opaque: true},
 	{Name: "http2server", Package: "net/http"},
+	{Name: "httpcookiemaxnum", Package: "net/http", Changed: 24, Old: "0"},
 	{Name: "httplaxcontentlength", Package: "net/http", Changed: 22, Old: "1"},
 	{Name: "httpmuxgo121", Package: "net/http", Changed: 22, Old: "1"},
 	{Name: "httpservecontentkeepheaders", Package: "net/http", Changed: 23, Old: "1"},
diff --git a/src/net/http/cookie.go b/src/net/http/cookie.go
index efe6cc3e77e5b5..f74bc1043c509e 100644
--- a/src/net/http/cookie.go
+++ b/src/net/http/cookie.go
@@ -7,6 +7,7 @@ package http
 import (
 	"errors"
 	"fmt"
+	"internal/godebug"
 	"log"
 	"net"
 	"net/http/internal/ascii"
@@ -16,6 +17,8 @@ import (
 	"time"
 )
 
+var httpcookiemaxnum = godebug.New("httpcookiemaxnum")
+
 // A Cookie represents an HTTP cookie as sent in the Set-Cookie header of an
 // HTTP response or the Cookie header of an HTTP request.
 //
@@ -58,16 +61,37 @@ const (
 )
 
 var (
-	errBlankCookie           = errors.New("http: blank cookie")
-	errEqualNotFoundInCookie = errors.New("http: '=' not found in cookie")
-	errInvalidCookieName     = errors.New("http: invalid cookie name")
-	errInvalidCookieValue    = errors.New("http: invalid cookie value")
+	errBlankCookie            = errors.New("http: blank cookie")
+	errEqualNotFoundInCookie  = errors.New("http: '=' not found in cookie")
+	errInvalidCookieName      = errors.New("http: invalid cookie name")
+	errInvalidCookieValue     = errors.New("http: invalid cookie value")
+	errCookieNumLimitExceeded = errors.New("http: number of cookies exceeded limit")
 )
 
+const defaultCookieMaxNum = 3000
+
+func cookieNumWithinMax(cookieNum int) bool {
+	withinDefaultMax := cookieNum <= defaultCookieMaxNum
+	if httpcookiemaxnum.Value() == "" {
+		return withinDefaultMax
+	}
+	if customMax, err := strconv.Atoi(httpcookiemaxnum.Value()); err == nil {
+		withinCustomMax := customMax == 0 || cookieNum <= customMax
+		if withinDefaultMax != withinCustomMax {
+			httpcookiemaxnum.IncNonDefault()
+		}
+		return withinCustomMax
+	}
+	return withinDefaultMax
+}
+
 // ParseCookie parses a Cookie header value and returns all the cookies
 // which were set in it. Since the same cookie name can appear multiple times
 // the returned Values can contain more than one value for a given key.
 func ParseCookie(line string) ([]*Cookie, error) {
+	if !cookieNumWithinMax(strings.Count(line, ";") + 1) {
+		return nil, errCookieNumLimitExceeded
+	}
 	parts := strings.Split(textproto.TrimString(line), ";")
 	if len(parts) == 1 && parts[0] == "" {
 		return nil, errBlankCookie
@@ -197,11 +221,21 @@ func ParseSetCookie(line string) (*Cookie, error) {
 
 // readSetCookies parses all "Set-Cookie" values from
 // the header h and returns the successfully parsed Cookies.
+//
+// If the amount of cookies exceeds CookieNumLimit, and httpcookielimitnum
+// GODEBUG option is not explicitly turned off, this function will silently
+// fail and return an empty slice.
 func readSetCookies(h Header) []*Cookie {
 	cookieCount := len(h["Set-Cookie"])
 	if cookieCount == 0 {
 		return []*Cookie{}
 	}
+	// Cookie limit was unfortunately introduced at a later point in time.
+	// As such, we can only fail by returning an empty slice rather than
+	// explicit error.
+	if !cookieNumWithinMax(cookieCount) {
+		return []*Cookie{}
+	}
 	cookies := make([]*Cookie, 0, cookieCount)
 	for _, line := range h["Set-Cookie"] {
 		if cookie, err := ParseSetCookie(line); err == nil {
@@ -329,13 +363,28 @@ func (c *Cookie) Valid() error {
 // readCookies parses all "Cookie" values from the header h and
 // returns the successfully parsed Cookies.
 //
-// if filter isn't empty, only cookies of that name are returned.
+// If filter isn't empty, only cookies of that name are returned.
+//
+// If the amount of cookies exceeds CookieNumLimit, and httpcookielimitnum
+// GODEBUG option is not explicitly turned off, this function will silently
+// fail and return an empty slice.
 func readCookies(h Header, filter string) []*Cookie {
 	lines := h["Cookie"]
 	if len(lines) == 0 {
 		return []*Cookie{}
 	}
 
+	// Cookie limit was unfortunately introduced at a later point in time.
+	// As such, we can only fail by returning an empty slice rather than
+	// explicit error.
+	cookieCount := 0
+	for _, line := range lines {
+		cookieCount += strings.Count(line, ";") + 1
+	}
+	if !cookieNumWithinMax(cookieCount) {
+		return []*Cookie{}
+	}
+
 	cookies := make([]*Cookie, 0, len(lines)+strings.Count(lines[0], ";"))
 	for _, line := range lines {
 		line = textproto.TrimString(line)
diff --git a/src/net/http/cookie_test.go b/src/net/http/cookie_test.go
index 8db4957b2cc37d..f452b4ec76830f 100644
--- a/src/net/http/cookie_test.go
+++ b/src/net/http/cookie_test.go
@@ -11,6 +11,7 @@ import (
 	"log"
 	"os"
 	"reflect"
+	"slices"
 	"strings"
 	"testing"
 	"time"
@@ -255,16 +256,17 @@ func TestAddCookie(t *testing.T) {
 }
 
 var readSetCookiesTests = []struct {
-	Header  Header
-	Cookies []*Cookie
+	header  Header
+	cookies []*Cookie
+	godebug string
 }{
 	{
-		Header{"Set-Cookie": {"Cookie-1=v$1"}},
-		[]*Cookie{{Name: "Cookie-1", Value: "v$1", Raw: "Cookie-1=v$1"}},
+		header:  Header{"Set-Cookie": {"Cookie-1=v$1"}},
+		cookies: []*Cookie{{Name: "Cookie-1", Value: "v$1", Raw: "Cookie-1=v$1"}},
 	},
 	{
-		Header{"Set-Cookie": {"NID=99=YsDT5i3E-CXax-; expires=Wed, 23-Nov-2011 01:05:03 GMT; path=/; domain=.google.ch; HttpOnly"}},
-		[]*Cookie{{
+		header: Header{"Set-Cookie": {"NID=99=YsDT5i3E-CXax-; expires=Wed, 23-Nov-2011 01:05:03 GMT; path=/; domain=.google.ch; HttpOnly"}},
+		cookies: []*Cookie{{
 			Name:       "NID",
 			Value:      "99=YsDT5i3E-CXax-",
 			Path:       "/",
@@ -276,8 +278,8 @@ var readSetCookiesTests = []struct {
 		}},
 	},
 	{
-		Header{"Set-Cookie": {".ASPXAUTH=7E3AA; expires=Wed, 07-Mar-2012 14:25:06 GMT; path=/; HttpOnly"}},
-		[]*Cookie{{
+		header: Header{"Set-Cookie": {".ASPXAUTH=7E3AA; expires=Wed, 07-Mar-2012 14:25:06 GMT; path=/; HttpOnly"}},
+		cookies: []*Cookie{{
 			Name:       ".ASPXAUTH",
 			Value:      "7E3AA",
 			Path:       "/",
@@ -288,8 +290,8 @@ var readSetCookiesTests = []struct {
 		}},
 	},
 	{
-		Header{"Set-Cookie": {"ASP.NET_SessionId=foo; path=/; HttpOnly"}},
-		[]*Cookie{{
+		header: Header{"Set-Cookie": {"ASP.NET_SessionId=foo; path=/; HttpOnly"}},
+		cookies: []*Cookie{{
 			Name:     "ASP.NET_SessionId",
 			Value:    "foo",
 			Path:     "/",
@@ -298,8 +300,8 @@ var readSetCookiesTests = []struct {
 		}},
 	},
 	{
-		Header{"Set-Cookie": {"samesitedefault=foo; SameSite"}},
-		[]*Cookie{{
+		header: Header{"Set-Cookie": {"samesitedefault=foo; SameSite"}},
+		cookies: []*Cookie{{
 			Name:     "samesitedefault",
 			Value:    "foo",
 			SameSite: SameSiteDefaultMode,
@@ -307,8 +309,8 @@ var readSetCookiesTests = []struct {
 		}},
 	},
 	{
-		Header{"Set-Cookie": {"samesiteinvalidisdefault=foo; SameSite=invalid"}},
-		[]*Cookie{{
+		header: Header{"Set-Cookie": {"samesiteinvalidisdefault=foo; SameSite=invalid"}},
+		cookies: []*Cookie{{
 			Name:     "samesiteinvalidisdefault",
 			Value:    "foo",
 			SameSite: SameSiteDefaultMode,
@@ -316,8 +318,8 @@ var readSetCookiesTests = []struct {
 		}},
 	},
 	{
-		Header{"Set-Cookie": {"samesitelax=foo; SameSite=Lax"}},
-		[]*Cookie{{
+		header: Header{"Set-Cookie": {"samesitelax=foo; SameSite=Lax"}},
+		cookies: []*Cookie{{
 			Name:     "samesitelax",
 			Value:    "foo",
 			SameSite: SameSiteLaxMode,
@@ -325,8 +327,8 @@ var readSetCookiesTests = []struct {
 		}},
 	},
 	{
-		Header{"Set-Cookie": {"samesitestrict=foo; SameSite=Strict"}},
-		[]*Cookie{{
+		header: Header{"Set-Cookie": {"samesitestrict=foo; SameSite=Strict"}},
+		cookies: []*Cookie{{
 			Name:     "samesitestrict",
 			Value:    "foo",
 			SameSite: SameSiteStrictMode,
@@ -334,8 +336,8 @@ var readSetCookiesTests = []struct {
 		}},
 	},
 	{
-		Header{"Set-Cookie": {"samesitenone=foo; SameSite=None"}},
-		[]*Cookie{{
+		header: Header{"Set-Cookie": {"samesitenone=foo; SameSite=None"}},
+		cookies: []*Cookie{{
 			Name:     "samesitenone",
 			Value:    "foo",
 			SameSite: SameSiteNoneMode,
@@ -345,47 +347,66 @@ var readSetCookiesTests = []struct {
 	// Make sure we can properly read back the Set-Cookie headers we create
 	// for values containing spaces or commas:
 	{
-		Header{"Set-Cookie": {`special-1=a z`}},
-		[]*Cookie{{Name: "special-1", Value: "a z", Raw: `special-1=a z`}},
+		header:  Header{"Set-Cookie": {`special-1=a z`}},
+		cookies: []*Cookie{{Name: "special-1", Value: "a z", Raw: `special-1=a z`}},
 	},
 	{
-		Header{"Set-Cookie": {`special-2=" z"`}},
-		[]*Cookie{{Name: "special-2", Value: " z", Quoted: true, Raw: `special-2=" z"`}},
+		header:  Header{"Set-Cookie": {`special-2=" z"`}},
+		cookies: []*Cookie{{Name: "special-2", Value: " z", Quoted: true, Raw: `special-2=" z"`}},
 	},
 	{
-		Header{"Set-Cookie": {`special-3="a "`}},
-		[]*Cookie{{Name: "special-3", Value: "a ", Quoted: true, Raw: `special-3="a "`}},
+		header:  Header{"Set-Cookie": {`special-3="a "`}},
+		cookies: []*Cookie{{Name: "special-3", Value: "a ", Quoted: true, Raw: `special-3="a "`}},
 	},
 	{
-		Header{"Set-Cookie": {`special-4=" "`}},
-		[]*Cookie{{Name: "special-4", Value: " ", Quoted: true, Raw: `special-4=" "`}},
+		header:  Header{"Set-Cookie": {`special-4=" "`}},
+		cookies: []*Cookie{{Name: "special-4", Value: " ", Quoted: true, Raw: `special-4=" "`}},
 	},
 	{
-		Header{"Set-Cookie": {`special-5=a,z`}},
-		[]*Cookie{{Name: "special-5", Value: "a,z", Raw: `special-5=a,z`}},
+		header:  Header{"Set-Cookie": {`special-5=a,z`}},
+		cookies: []*Cookie{{Name: "special-5", Value: "a,z", Raw: `special-5=a,z`}},
 	},
 	{
-		Header{"Set-Cookie": {`special-6=",z"`}},
-		[]*Cookie{{Name: "special-6", Value: ",z", Quoted: true, Raw: `special-6=",z"`}},
+		header:  Header{"Set-Cookie": {`special-6=",z"`}},
+		cookies: []*Cookie{{Name: "special-6", Value: ",z", Quoted: true, Raw: `special-6=",z"`}},
 	},
 	{
-		Header{"Set-Cookie": {`special-7=a,`}},
-		[]*Cookie{{Name: "special-7", Value: "a,", Raw: `special-7=a,`}},
+		header:  Header{"Set-Cookie": {`special-7=a,`}},
+		cookies: []*Cookie{{Name: "special-7", Value: "a,", Raw: `special-7=a,`}},
 	},
 	{
-		Header{"Set-Cookie": {`special-8=","`}},
-		[]*Cookie{{Name: "special-8", Value: ",", Quoted: true, Raw: `special-8=","`}},
+		header:  Header{"Set-Cookie": {`special-8=","`}},
+		cookies: []*Cookie{{Name: "special-8", Value: ",", Quoted: true, Raw: `special-8=","`}},
 	},
 	// Make sure we can properly read back the Set-Cookie headers
 	// for names containing spaces:
 	{
-		Header{"Set-Cookie": {`special-9 =","`}},
-		[]*Cookie{{Name: "special-9", Value: ",", Quoted: true, Raw: `special-9 =","`}},
+		header:  Header{"Set-Cookie": {`special-9 =","`}},
+		cookies: []*Cookie{{Name: "special-9", Value: ",", Quoted: true, Raw: `special-9 =","`}},
 	},
 	// Quoted values (issue #46443)
 	{
-		Header{"Set-Cookie": {`cookie="quoted"`}},
-		[]*Cookie{{Name: "cookie", Value: "quoted", Quoted: true, Raw: `cookie="quoted"`}},
+		header:  Header{"Set-Cookie": {`cookie="quoted"`}},
+		cookies: []*Cookie{{Name: "cookie", Value: "quoted", Quoted: true, Raw: `cookie="quoted"`}},
+	},
+	{
+		header:  Header{"Set-Cookie": slices.Repeat([]string{"a="}, defaultCookieMaxNum+1)},
+		cookies: []*Cookie{},
+	},
+	{
+		header:  Header{"Set-Cookie": slices.Repeat([]string{"a="}, 10)},
+		cookies: []*Cookie{},
+		godebug: "httpcookiemaxnum=5",
+	},
+	{
+		header:  Header{"Set-Cookie": strings.Split(strings.Repeat(";a=", defaultCookieMaxNum+1)[1:], ";")},
+		cookies: slices.Repeat([]*Cookie{{Name: "a", Value: "", Quoted: false, Raw: "a="}}, defaultCookieMaxNum+1),
+		godebug: "httpcookiemaxnum=0",
+	},
+	{
+		header:  Header{"Set-Cookie": strings.Split(strings.Repeat(";a=", defaultCookieMaxNum+1)[1:], ";")},
+		cookies: slices.Repeat([]*Cookie{{Name: "a", Value: "", Quoted: false, Raw: "a="}}, defaultCookieMaxNum+1),
+		godebug: fmt.Sprintf("httpcookiemaxnum=%v", defaultCookieMaxNum+1),
 	},
 
 	// TODO(bradfitz): users have reported seeing this in the
@@ -405,79 +426,103 @@ func toJSON(v any) string {
 
 func TestReadSetCookies(t *testing.T) {
 	for i, tt := range readSetCookiesTests {
+		t.Setenv("GODEBUG", tt.godebug)
 		for n := 0; n < 2; n++ { // to verify readSetCookies doesn't mutate its input
-			c := readSetCookies(tt.Header)
-			if !reflect.DeepEqual(c, tt.Cookies) {
-				t.Errorf("#%d readSetCookies: have\n%s\nwant\n%s\n", i, toJSON(c), toJSON(tt.Cookies))
+			c := readSetCookies(tt.header)
+			if !reflect.DeepEqual(c, tt.cookies) {
+				t.Errorf("#%d readSetCookies: have\n%s\nwant\n%s\n", i, toJSON(c), toJSON(tt.cookies))
 			}
 		}
 	}
 }
 
 var readCookiesTests = []struct {
-	Header  Header
-	Filter  string
-	Cookies []*Cookie
+	header  Header
+	filter  string
+	cookies []*Cookie
+	godebug string
 }{
 	{
-		Header{"Cookie": {"Cookie-1=v$1", "c2=v2"}},
-		"",
-		[]*Cookie{
+		header: Header{"Cookie": {"Cookie-1=v$1", "c2=v2"}},
+		filter: "",
+		cookies: []*Cookie{
 			{Name: "Cookie-1", Value: "v$1"},
 			{Name: "c2", Value: "v2"},
 		},
 	},
 	{
-		Header{"Cookie": {"Cookie-1=v$1", "c2=v2"}},
-		"c2",
-		[]*Cookie{
+		header: Header{"Cookie": {"Cookie-1=v$1", "c2=v2"}},
+		filter: "c2",
+		cookies: []*Cookie{
 			{Name: "c2", Value: "v2"},
 		},
 	},
 	{
-		Header{"Cookie": {"Cookie-1=v$1; c2=v2"}},
-		"",
-		[]*Cookie{
+		header: Header{"Cookie": {"Cookie-1=v$1; c2=v2"}},
+		filter: "",
+		cookies: []*Cookie{
 			{Name: "Cookie-1", Value: "v$1"},
 			{Name: "c2", Value: "v2"},
 		},
 	},
 	{
-		Header{"Cookie": {"Cookie-1=v$1; c2=v2"}},
-		"c2",
-		[]*Cookie{
+		header: Header{"Cookie": {"Cookie-1=v$1; c2=v2"}},
+		filter: "c2",
+		cookies: []*Cookie{
 			{Name: "c2", Value: "v2"},
 		},
 	},
 	{
-		Header{"Cookie": {`Cookie-1="v$1"; c2="v2"`}},
-		"",
-		[]*Cookie{
+		header: Header{"Cookie": {`Cookie-1="v$1"; c2="v2"`}},
+		filter: "",
+		cookies: []*Cookie{
 			{Name: "Cookie-1", Value: "v$1", Quoted: true},
 			{Name: "c2", Value: "v2", Quoted: true},
 		},
 	},
 	{
-		Header{"Cookie": {`Cookie-1="v$1"; c2=v2;`}},
-		"",
-		[]*Cookie{
+		header: Header{"Cookie": {`Cookie-1="v$1"; c2=v2;`}},
+		filter: "",
+		cookies: []*Cookie{
 			{Name: "Cookie-1", Value: "v$1", Quoted: true},
 			{Name: "c2", Value: "v2"},
 		},
 	},
 	{
-		Header{"Cookie": {``}},
-		"",
-		[]*Cookie{},
+		header:  Header{"Cookie": {``}},
+		filter:  "",
+		cookies: []*Cookie{},
+	},
+	// GODEBUG=httpcookiemaxnum should work regardless if all cookies are sent
+	// via one "Cookie" field, or multiple fields.
+	{
+		header:  Header{"Cookie": {strings.Repeat(";a=", defaultCookieMaxNum+1)[1:]}},
+		cookies: []*Cookie{},
+	},
+	{
+		header:  Header{"Cookie": slices.Repeat([]string{"a="}, 10)},
+		cookies: []*Cookie{},
+		godebug: "httpcookiemaxnum=5",
+	},
+	{
+		header:  Header{"Cookie": {strings.Repeat(";a=", defaultCookieMaxNum+1)[1:]}},
+		cookies: slices.Repeat([]*Cookie{{Name: "a", Value: "", Quoted: false}}, defaultCookieMaxNum+1),
+		godebug: "httpcookiemaxnum=0",
+	},
+	{
+		header:  Header{"Cookie": slices.Repeat([]string{"a="}, defaultCookieMaxNum+1)},
+		cookies: slices.Repeat([]*Cookie{{Name: "a", Value: "", Quoted: false}}, defaultCookieMaxNum+1),
+		godebug: fmt.Sprintf("httpcookiemaxnum=%v", defaultCookieMaxNum+1),
 	},
 }
 
 func TestReadCookies(t *testing.T) {
 	for i, tt := range readCookiesTests {
+		t.Setenv("GODEBUG", tt.godebug)
 		for n := 0; n < 2; n++ { // to verify readCookies doesn't mutate its input
-			c := readCookies(tt.Header, tt.Filter)
-			if !reflect.DeepEqual(c, tt.Cookies) {
-				t.Errorf("#%d readCookies:\nhave: %s\nwant: %s\n", i, toJSON(c), toJSON(tt.Cookies))
+			c := readCookies(tt.header, tt.filter)
+			if !reflect.DeepEqual(c, tt.cookies) {
+				t.Errorf("#%d readCookies:\nhave: %s\nwant: %s\n", i, toJSON(c), toJSON(tt.cookies))
 			}
 		}
 	}
@@ -690,6 +735,7 @@ func TestParseCookie(t *testing.T) {
 		line    string
 		cookies []*Cookie
 		err     error
+		godebug string
 	}{
 		{
 			line:    "Cookie-1=v$1",
@@ -723,8 +769,28 @@ func TestParseCookie(t *testing.T) {
 			line: "k1=\\",
 			err:  errInvalidCookieValue,
 		},
+		{
+			line: strings.Repeat(";a=", defaultCookieMaxNum+1)[1:],
+			err:  errCookieNumLimitExceeded,
+		},
+		{
+			line:    strings.Repeat(";a=", 10)[1:],
+			err:     errCookieNumLimitExceeded,
+			godebug: "httpcookiemaxnum=5",
+		},
+		{
+			line:    strings.Repeat(";a=", defaultCookieMaxNum+1)[1:],
+			cookies: slices.Repeat([]*Cookie{{Name: "a", Value: "", Quoted: false}}, defaultCookieMaxNum+1),
+			godebug: "httpcookiemaxnum=0",
+		},
+		{
+			line:    strings.Repeat(";a=", defaultCookieMaxNum+1)[1:],
+			cookies: slices.Repeat([]*Cookie{{Name: "a", Value: "", Quoted: false}}, defaultCookieMaxNum+1),
+			godebug: fmt.Sprintf("httpcookiemaxnum=%v", defaultCookieMaxNum+1),
+		},
 	}
 	for i, tt := range tests {
+		t.Setenv("GODEBUG", tt.godebug)
 		gotCookies, gotErr := ParseCookie(tt.line)
 		if !errors.Is(gotErr, tt.err) {
 			t.Errorf("#%d ParseCookie got error %v, want error %v", i, gotErr, tt.err)
diff --git a/src/runtime/metrics/doc.go b/src/runtime/metrics/doc.go
index e40ce25ff9d1bc..05646132ce4e69 100644
--- a/src/runtime/metrics/doc.go
+++ b/src/runtime/metrics/doc.go
@@ -309,6 +309,11 @@ Below is the full list of supported metrics, ordered lexicographically.
 		The number of non-default behaviors executed by the net/http
 		package due to a non-default GODEBUG=http2server=... setting.
 
+	/godebug/non-default-behavior/httpcookiemaxnum:events
+		The number of non-default behaviors executed by the net/http
+		package due to a non-default GODEBUG=httpcookiemaxnum=...
+		setting.
+
 	/godebug/non-default-behavior/httplaxcontentlength:events
 		The number of non-default behaviors executed by the net/http
 		package due to a non-default GODEBUG=httplaxcontentlength=...

From 8709a41d5ef7321f486a1857f189c3fee20e8edd Mon Sep 17 00:00:00 2001
From: Nicholas Husin 
Date: Wed, 3 Sep 2025 09:30:56 -0400
Subject: [PATCH 082/229] encoding/asn1: prevent memory exhaustion when parsing
 using internal/saferio

Within parseSequenceOf, reflect.MakeSlice is being used to pre-allocate
a slice that is needed in order to fully validate the given DER payload.
The size of the slice allocated are also multiple times larger than the
input DER:

- When using asn1.Unmarshal directly, the allocated slice is ~28x
  larger.
- When passing in DER using x509.ParseCertificateRequest, the allocated
  slice is ~48x larger.
- When passing in DER using ocsp.ParseResponse, the allocated slice is
  ~137x larger.

As a result, a malicious actor can craft a big empty DER payload,
resulting in an unnecessary large allocation of memories. This can be a
way to cause memory exhaustion.

To prevent this, we now use SliceCapWithSize within internal/saferio to
enforce a memory allocation cap.

Thanks to Jakub Ciolek for reporting this issue.

For #75671
Fixes CVE-2025-58185

Change-Id: Id50e76187eda43f594be75e516b9ca1d2ae6f428
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2700
Reviewed-by: Roland Shoemaker 
Reviewed-by: Damien Neil 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709856
Reviewed-by: Carlos Amedee 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Michael Pratt 
---
 src/encoding/asn1/asn1.go      | 10 ++++++++-
 src/encoding/asn1/asn1_test.go | 38 ++++++++++++++++++++++++++++++++++
 src/go/build/deps_test.go      |  2 +-
 3 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/src/encoding/asn1/asn1.go b/src/encoding/asn1/asn1.go
index 0b64f06d368b53..f4be515b98ef1c 100644
--- a/src/encoding/asn1/asn1.go
+++ b/src/encoding/asn1/asn1.go
@@ -22,6 +22,7 @@ package asn1
 import (
 	"errors"
 	"fmt"
+	"internal/saferio"
 	"math"
 	"math/big"
 	"reflect"
@@ -666,10 +667,17 @@ func parseSequenceOf(bytes []byte, sliceType reflect.Type, elemType reflect.Type
 		offset += t.length
 		numElements++
 	}
-	ret = reflect.MakeSlice(sliceType, numElements, numElements)
+	elemSize := uint64(elemType.Size())
+	safeCap := saferio.SliceCapWithSize(elemSize, uint64(numElements))
+	if safeCap < 0 {
+		err = SyntaxError{fmt.Sprintf("%s slice too big: %d elements of %d bytes", elemType.Kind(), numElements, elemSize)}
+		return
+	}
+	ret = reflect.MakeSlice(sliceType, 0, safeCap)
 	params := fieldParameters{}
 	offset := 0
 	for i := 0; i < numElements; i++ {
+		ret = reflect.Append(ret, reflect.Zero(elemType))
 		offset, err = parseField(ret.Index(i), bytes, offset, params)
 		if err != nil {
 			return
diff --git a/src/encoding/asn1/asn1_test.go b/src/encoding/asn1/asn1_test.go
index 0597740bd5e5ec..41cc0ba50ec304 100644
--- a/src/encoding/asn1/asn1_test.go
+++ b/src/encoding/asn1/asn1_test.go
@@ -7,10 +7,12 @@ package asn1
 import (
 	"bytes"
 	"encoding/hex"
+	"errors"
 	"fmt"
 	"math"
 	"math/big"
 	"reflect"
+	"runtime"
 	"strings"
 	"testing"
 	"time"
@@ -1216,3 +1218,39 @@ func TestImplicitTypeRoundtrip(t *testing.T) {
 		t.Fatalf("Unexpected diff after roundtripping struct\na: %#v\nb: %#v", a, b)
 	}
 }
+
+func TestParsingMemoryConsumption(t *testing.T) {
+	// Craft a syntatically valid, but empty, ~10 MB DER bomb. A successful
+	// unmarshal of this bomb should yield ~280 MB. However, the parsing should
+	// fail due to the empty content; and, in such cases, we want to make sure
+	// that we do not unnecessarily allocate memories.
+	derBomb := make([]byte, 10_000_000)
+	for i := range derBomb {
+		derBomb[i] = 0x30
+	}
+	derBomb = append([]byte{0x30, 0x83, 0x98, 0x96, 0x80}, derBomb...)
+
+	var m runtime.MemStats
+	runtime.GC()
+	runtime.ReadMemStats(&m)
+	memBefore := m.TotalAlloc
+
+	var out []struct {
+		Id       []int
+		Critical bool `asn1:"optional"`
+		Value    []byte
+	}
+	_, err := Unmarshal(derBomb, &out)
+	if !errors.As(err, &SyntaxError{}) {
+		t.Fatalf("Incorrect error result: want (%v), but got (%v) instead", &SyntaxError{}, err)
+	}
+
+	runtime.ReadMemStats(&m)
+	memDiff := m.TotalAlloc - memBefore
+
+	// Ensure that the memory allocated does not exceed 10<<21 (~20 MB) when
+	// the parsing fails.
+	if memDiff > 10<<21 {
+		t.Errorf("Too much memory allocated while parsing DER: %v MiB", memDiff/1024/1024)
+	}
+}
diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index c76b254b23ffc8..d6a18c19fab024 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -564,7 +564,7 @@ var depsRules = `
 
 	# CRYPTO-MATH is crypto that exposes math/big APIs - no cgo, net; fmt now ok.
 
-	CRYPTO, FMT, math/big
+	CRYPTO, FMT, math/big, internal/saferio
 	< crypto/internal/boring/bbig
 	< crypto/internal/fips140cache
 	< crypto/rand

From 3ee761739b0cbb074f5a6e8b28b491664ec1414a Mon Sep 17 00:00:00 2001
From: Michael Pratt 
Date: Mon, 6 Oct 2025 17:28:37 -0400
Subject: [PATCH 083/229] runtime: free spanQueue on P destroy

Span queues must be empty when destroying a P since we are outside of
the mark phase. But we don't actually free them, so they simply sit
around using memory. More importantly, they are still in
work.spanSPMCs.all, so freeDeadSpanSPMCs must continue traversing past
them until the end of time.

Prior to CL 709575, keeping them in work.spanSPMCs.all allowed programs
with low GOMAXPROCS to continue triggering the bug if they ever had high
GOMAXPROCS in the past.

The spanSPMCs list is singly-linked, so it is not efficient to remove a
random element from the middle. Instead, we simply mark it as dead to
all freeDeadSpanSPMCs to free it when it scans the full list.

For #75771.

Change-Id: I6a6a636cfa22a4bdef0c273d083c91553e923fe5
Reviewed-on: https://go-review.googlesource.com/c/go/+/709656
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Knyszek 
---
 src/runtime/mgcmark_greenteagc.go   | 34 +++++++++++++++++++++++++++++
 src/runtime/mgcmark_nogreenteagc.go |  3 +++
 src/runtime/proc.go                 |  2 ++
 3 files changed, 39 insertions(+)

diff --git a/src/runtime/mgcmark_greenteagc.go b/src/runtime/mgcmark_greenteagc.go
index 7f8d60349ffb67..6ebd7ced81b901 100644
--- a/src/runtime/mgcmark_greenteagc.go
+++ b/src/runtime/mgcmark_greenteagc.go
@@ -618,6 +618,40 @@ func (q *spanQueue) refill(r *spanSPMC) objptr {
 	return q.tryGetFast()
 }
 
+// destroy frees all chains in an empty spanQueue.
+//
+// Preconditions:
+// - World is stopped.
+// - GC is outside of the mark phase.
+// - (Therefore) the queue is empty.
+func (q *spanQueue) destroy() {
+	assertWorldStopped()
+	if gcphase != _GCoff {
+		throw("spanQueue.destroy during the mark phase")
+	}
+	if !q.empty() {
+		throw("spanQueue.destroy on non-empty queue")
+	}
+
+	lock(&work.spanSPMCs.lock)
+
+	// Mark each ring as dead. The sweeper will actually free them.
+	//
+	// N.B., we could free directly here, but work.spanSPMCs.all is a
+	// singly-linked list, so we'd need to walk the entire list to find the
+	// previous node. If the list becomes doubly-linked, we can free
+	// directly.
+	for r := (*spanSPMC)(q.chain.tail.Load()); r != nil; r = (*spanSPMC)(r.prev.Load()) {
+		r.dead.Store(true)
+	}
+
+	q.chain.head = nil
+	q.chain.tail.Store(nil)
+	q.putsSinceDrain = 0
+
+	unlock(&work.spanSPMCs.lock)
+}
+
 // spanSPMC is a ring buffer of objptrs that represent spans.
 // Accessed without a lock.
 //
diff --git a/src/runtime/mgcmark_nogreenteagc.go b/src/runtime/mgcmark_nogreenteagc.go
index 883c3451abec6b..024565ef3e250d 100644
--- a/src/runtime/mgcmark_nogreenteagc.go
+++ b/src/runtime/mgcmark_nogreenteagc.go
@@ -63,6 +63,9 @@ func (q *spanQueue) empty() bool {
 	return true
 }
 
+func (q *spanQueue) destroy() {
+}
+
 type spanSPMC struct {
 	_ sys.NotInHeap
 }
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index d36895b046c8c6..fadd9a59639f87 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -5824,6 +5824,8 @@ func (pp *p) destroy() {
 		println("runtime: p id", pp.id, "destroyed during GC phase", phase)
 		throw("P destroyed while GC is running")
 	}
+	// We should free the queues though.
+	pp.gcw.spanq.destroy()
 
 	clear(pp.sudogbuf[:])
 	pp.sudogcache = pp.sudogbuf[:0]

From 7dd54e1fd7f3a25fccbb5c6ab7066e2baad23e66 Mon Sep 17 00:00:00 2001
From: Michael Pratt 
Date: Mon, 6 Oct 2025 17:55:06 -0400
Subject: [PATCH 084/229] runtime: make work.spanSPMCs.all doubly-linked

Making this a doubly-linked list allows spanQueue.destroy to immediately
remove and free rings rather than simply marking them as dead and
waiting for the sweeper to deal with them.

For #75771.

Change-Id: I6a6a636c0fb6be08ee967cb6d8f0577511a33c13
Reviewed-on: https://go-review.googlesource.com/c/go/+/709657
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Knyszek 
---
 src/runtime/mgcmark_greenteagc.go | 61 +++++++++++++++++++++----------
 1 file changed, 42 insertions(+), 19 deletions(-)

diff --git a/src/runtime/mgcmark_greenteagc.go b/src/runtime/mgcmark_greenteagc.go
index 6ebd7ced81b901..7b78611cf7b6fe 100644
--- a/src/runtime/mgcmark_greenteagc.go
+++ b/src/runtime/mgcmark_greenteagc.go
@@ -635,14 +635,22 @@ func (q *spanQueue) destroy() {
 
 	lock(&work.spanSPMCs.lock)
 
-	// Mark each ring as dead. The sweeper will actually free them.
-	//
-	// N.B., we could free directly here, but work.spanSPMCs.all is a
-	// singly-linked list, so we'd need to walk the entire list to find the
-	// previous node. If the list becomes doubly-linked, we can free
-	// directly.
+	// Remove and free each ring.
 	for r := (*spanSPMC)(q.chain.tail.Load()); r != nil; r = (*spanSPMC)(r.prev.Load()) {
-		r.dead.Store(true)
+		prev := r.allprev
+		next := r.allnext
+		if prev != nil {
+			prev.allnext = next
+		}
+		if next != nil {
+			next.allprev = prev
+		}
+		if work.spanSPMCs.all == r {
+			work.spanSPMCs.all = next
+		}
+
+		r.deinit()
+		mheap_.spanSPMCAlloc.free(unsafe.Pointer(r))
 	}
 
 	q.chain.head = nil
@@ -685,6 +693,11 @@ type spanSPMC struct {
 	// work.spanSPMCs.lock.
 	allnext *spanSPMC
 
+	// allprev is the link to the previous spanSPMC on the work.spanSPMCs
+	// list. This is used to find and free dead spanSPMCs. Protected by
+	// work.spanSPMCs.lock.
+	allprev *spanSPMC
+
 	// dead indicates whether the spanSPMC is no longer in use.
 	// Protected by the CAS to the prev field of the spanSPMC pointing
 	// to this spanSPMC. That is, whoever wins that CAS takes ownership
@@ -711,7 +724,11 @@ type spanSPMC struct {
 func newSpanSPMC(cap uint32) *spanSPMC {
 	lock(&work.spanSPMCs.lock)
 	r := (*spanSPMC)(mheap_.spanSPMCAlloc.alloc())
-	r.allnext = work.spanSPMCs.all
+	next := work.spanSPMCs.all
+	r.allnext = next
+	if next != nil {
+		next.allprev = r
+	}
 	work.spanSPMCs.all = r
 	unlock(&work.spanSPMCs.lock)
 
@@ -748,6 +765,8 @@ func (r *spanSPMC) deinit() {
 	r.head.Store(0)
 	r.tail.Store(0)
 	r.cap = 0
+	r.allnext = nil
+	r.allprev = nil
 }
 
 // slot returns a pointer to slot i%r.cap.
@@ -780,22 +799,26 @@ func freeDeadSpanSPMCs() {
 		unlock(&work.spanSPMCs.lock)
 		return
 	}
-	rp := &work.spanSPMCs.all
-	for {
-		r := *rp
-		if r == nil {
-			break
-		}
+	r := work.spanSPMCs.all
+	for r != nil {
+		next := r.allnext
 		if r.dead.Load() {
 			// It's dead. Deinitialize and free it.
-			*rp = r.allnext
+			prev := r.allprev
+			if prev != nil {
+				prev.allnext = next
+			}
+			if next != nil {
+				next.allprev = prev
+			}
+			if work.spanSPMCs.all == r {
+				work.spanSPMCs.all = next
+			}
+
 			r.deinit()
 			mheap_.spanSPMCAlloc.free(unsafe.Pointer(r))
-		} else {
-			// Still alive, likely in some P's chain.
-			// Skip it.
-			rp = &r.allnext
 		}
+		r = next
 	}
 	unlock(&work.spanSPMCs.lock)
 }

From f6f4e8b3ef21299db1ea3a343c3e55e91365a7fd Mon Sep 17 00:00:00 2001
From: Ethan Lee 
Date: Fri, 29 Aug 2025 17:35:55 +0000
Subject: [PATCH 085/229] net/url: enforce stricter parsing of bracketed IPv6
 hostnames

- Previously, url.Parse did not enforce validation of hostnames within
  square brackets.
- RFC 3986 stipulates that only IPv6 hostnames can be embedded within
  square brackets in a URL.
- Now, the parsing logic should strictly enforce that only IPv6
  hostnames can be resolved when in square brackets. IPv4, IPv4-mapped
  addresses and other input will be rejected.
- Update url_test to add test cases that cover the above scenarios.

Thanks to Enze Wang, Jingcheng Yang and Zehui Miao of Tsinghua
University for reporting this issue.

Fixes CVE-2025-47912
Fixes #75678

Change-Id: Iaa41432bf0ee86de95a39a03adae5729e4deb46c
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2680
Reviewed-by: Damien Neil 
Reviewed-by: Roland Shoemaker 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709857
TryBot-Bypass: Michael Pratt 
Reviewed-by: Carlos Amedee 
Auto-Submit: Michael Pratt 
---
 src/go/build/deps_test.go | 10 ++++++----
 src/net/url/url.go        | 42 +++++++++++++++++++++++++++++----------
 src/net/url/url_test.go   | 39 ++++++++++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+), 14 deletions(-)

diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index d6a18c19fab024..8966254d0d9110 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -237,7 +237,6 @@ var depsRules = `
 	  internal/types/errors,
 	  mime/quotedprintable,
 	  net/internal/socktest,
-	  net/url,
 	  runtime/trace,
 	  text/scanner,
 	  text/tabwriter;
@@ -300,6 +299,12 @@ var depsRules = `
 	FMT
 	< text/template/parse;
 
+	internal/bytealg, internal/itoa, math/bits, slices, strconv, unique
+	< net/netip;
+
+	FMT, net/netip
+	< net/url;
+
 	net/url, text/template/parse
 	< text/template
 	< internal/lazytemplate;
@@ -414,9 +419,6 @@ var depsRules = `
 	< golang.org/x/net/dns/dnsmessage,
 	  golang.org/x/net/lif;
 
-	internal/bytealg, internal/itoa, math/bits, slices, strconv, unique
-	< net/netip;
-
 	os, net/netip
 	< internal/routebsd;
 
diff --git a/src/net/url/url.go b/src/net/url/url.go
index 015c5b2751974a..292bc6bb12187a 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -16,6 +16,7 @@ import (
 	"errors"
 	"fmt"
 	"maps"
+	"net/netip"
 	"path"
 	"slices"
 	"strconv"
@@ -642,40 +643,61 @@ func parseAuthority(authority string) (user *Userinfo, host string, err error) {
 // parseHost parses host as an authority without user
 // information. That is, as host[:port].
 func parseHost(host string) (string, error) {
-	if strings.HasPrefix(host, "[") {
+	if openBracketIdx := strings.LastIndex(host, "["); openBracketIdx != -1 {
 		// Parse an IP-Literal in RFC 3986 and RFC 6874.
 		// E.g., "[fe80::1]", "[fe80::1%25en0]", "[fe80::1]:80".
-		i := strings.LastIndex(host, "]")
-		if i < 0 {
+		closeBracketIdx := strings.LastIndex(host, "]")
+		if closeBracketIdx < 0 {
 			return "", errors.New("missing ']' in host")
 		}
-		colonPort := host[i+1:]
+
+		colonPort := host[closeBracketIdx+1:]
 		if !validOptionalPort(colonPort) {
 			return "", fmt.Errorf("invalid port %q after host", colonPort)
 		}
+		unescapedColonPort, err := unescape(colonPort, encodeHost)
+		if err != nil {
+			return "", err
+		}
 
+		hostname := host[openBracketIdx+1 : closeBracketIdx]
+		var unescapedHostname string
 		// RFC 6874 defines that %25 (%-encoded percent) introduces
 		// the zone identifier, and the zone identifier can use basically
 		// any %-encoding it likes. That's different from the host, which
 		// can only %-encode non-ASCII bytes.
 		// We do impose some restrictions on the zone, to avoid stupidity
 		// like newlines.
-		zone := strings.Index(host[:i], "%25")
-		if zone >= 0 {
-			host1, err := unescape(host[:zone], encodeHost)
+		zoneIdx := strings.Index(hostname, "%25")
+		if zoneIdx >= 0 {
+			hostPart, err := unescape(hostname[:zoneIdx], encodeHost)
 			if err != nil {
 				return "", err
 			}
-			host2, err := unescape(host[zone:i], encodeZone)
+			zonePart, err := unescape(hostname[zoneIdx:], encodeZone)
 			if err != nil {
 				return "", err
 			}
-			host3, err := unescape(host[i:], encodeHost)
+			unescapedHostname = hostPart + zonePart
+		} else {
+			var err error
+			unescapedHostname, err = unescape(hostname, encodeHost)
 			if err != nil {
 				return "", err
 			}
-			return host1 + host2 + host3, nil
 		}
+
+		// Per RFC 3986, only a host identified by a valid
+		// IPv6 address can be enclosed by square brackets.
+		// This excludes any IPv4 or IPv4-mapped addresses.
+		addr, err := netip.ParseAddr(unescapedHostname)
+		if err != nil {
+			return "", fmt.Errorf("invalid host: %w", err)
+		}
+		if addr.Is4() || addr.Is4In6() {
+			return "", errors.New("invalid IPv6 host")
+		}
+		return "[" + unescapedHostname + "]" + unescapedColonPort, nil
 	} else if i := strings.LastIndex(host, ":"); i != -1 {
 		colonPort := host[i:]
 		if !validOptionalPort(colonPort) {
diff --git a/src/net/url/url_test.go b/src/net/url/url_test.go
index 16e08b63c6d098..32065583f27dd7 100644
--- a/src/net/url/url_test.go
+++ b/src/net/url/url_test.go
@@ -383,6 +383,16 @@ var urltests = []URLTest{
 		},
 		"",
 	},
+	// valid IPv6 host with port and path
+	{
+		"https://[2001:db8::1]:8443/test/path",
+		&URL{
+			Scheme: "https",
+			Host:   "[2001:db8::1]:8443",
+			Path:   "/test/path",
+		},
+		"",
+	},
 	// host subcomponent; IPv6 address with zone identifier in RFC 6874
 	{
 		"http://[fe80::1%25en0]/", // alphanum zone identifier
@@ -707,6 +717,24 @@ var parseRequestURLTests = []struct {
 	// RFC 6874.
 	{"http://[fe80::1%en0]/", false},
 	{"http://[fe80::1%en0]:8080/", false},
+
+	// Tests exercising RFC 3986 compliance
+	{"https://[1:2:3:4:5:6:7:8]", true},             // full IPv6 address
+	{"https://[2001:db8::a:b:c:d]", true},           // compressed IPv6 address
+	{"https://[fe80::1%25eth0]", true},              // link-local address with zone ID (interface name)
+	{"https://[fe80::abc:def%254]", true},           // link-local address with zone ID (interface index)
+	{"https://[2001:db8::1]/path", true},            // compressed IPv6 address with path
+	{"https://[fe80::1%25eth0]/path?query=1", true}, // link-local with zone, path, and query
+
+	{"https://[::ffff:192.0.2.1]", false},
+	{"https://[:1] ", false},
+	{"https://[1:2:3:4:5:6:7:8:9]", false},
+	{"https://[1::1::1]", false},
+	{"https://[1:2:3:]", false},
+	{"https://[ffff::127.0.0.4000]", false},
+	{"https://[0:0::test.com]:80", false},
+	{"https://[2001:db8::test.com]", false},
+	{"https://[test.com]", false},
 }
 
 func TestParseRequestURI(t *testing.T) {
@@ -1643,6 +1671,17 @@ func TestParseErrors(t *testing.T) {
 		{"cache_object:foo", true},
 		{"cache_object:foo/bar", true},
 		{"cache_object/:foo/bar", false},
+
+		{"http://[192.168.0.1]/", true},             // IPv4 in brackets
+		{"http://[192.168.0.1]:8080/", true},        // IPv4 in brackets with port
+		{"http://[::ffff:192.168.0.1]/", true},      // IPv4-mapped IPv6 in brackets
+		{"http://[::ffff:192.168.0.1]:8080/", true}, // IPv4-mapped IPv6 in brackets with port
+		{"http://[::ffff:c0a8:1]/", true},           // IPv4-mapped IPv6 in brackets (hex)
+		{"http://[not-an-ip]/", true},               // invalid IP string in brackets
+		{"http://[fe80::1%foo]/", true},             // invalid zone format in brackets
+		{"http://[fe80::1", true},                   // missing closing bracket
+		{"http://fe80::1]/", true},                  // missing opening bracket
+		{"http://[test.com]/", true},                // domain name in brackets
 	}
 	for _, tt := range tests {
 		u, err := Parse(tt.in)

From 5ce8cd16f3859ec5ac4106ad8ec15d6236f4501b Mon Sep 17 00:00:00 2001
From: Roland Shoemaker 
Date: Tue, 30 Sep 2025 11:16:56 -0700
Subject: [PATCH 086/229] encoding/pem: make Decode complexity linear

Because Decode scanned the input first for the first BEGIN line, and
then the first END line, the complexity of Decode is quadratic. If the
input contained a large number of BEGINs and then a single END right at
the end of the input, we would find the first BEGIN, and then scan the
entire input for the END, and fail to parse the block, so move onto the
next BEGIN, scan the entire input for the END, etc.

Instead, look for the first END in the input, and then the first BEGIN
that precedes the found END. We then process the bytes between the BEGIN
and END, and move onto the bytes after the END for further processing.
This gives us linear complexity.

Fixes CVE-2025-61723
Fixes #75676

Change-Id: I813c4f63e78bca4054226c53e13865c781564ccf
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2921
Reviewed-by: Nicholas Husin 
Reviewed-by: Damien Neil 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709858
TryBot-Bypass: Michael Pratt 
Auto-Submit: Michael Pratt 
Reviewed-by: Carlos Amedee 
---
 src/encoding/pem/pem.go      | 67 ++++++++++++++++++++----------------
 src/encoding/pem/pem_test.go | 13 +++----
 2 files changed, 44 insertions(+), 36 deletions(-)

diff --git a/src/encoding/pem/pem.go b/src/encoding/pem/pem.go
index dcc7416ee21ffe..21887008ca2182 100644
--- a/src/encoding/pem/pem.go
+++ b/src/encoding/pem/pem.go
@@ -37,7 +37,7 @@ type Block struct {
 // line bytes. The remainder of the byte array (also not including the new line
 // bytes) is also returned and this will always be smaller than the original
 // argument.
-func getLine(data []byte) (line, rest []byte) {
+func getLine(data []byte) (line, rest []byte, consumed int) {
 	i := bytes.IndexByte(data, '\n')
 	var j int
 	if i < 0 {
@@ -49,7 +49,7 @@ func getLine(data []byte) (line, rest []byte) {
 			i--
 		}
 	}
-	return bytes.TrimRight(data[0:i], " \t"), data[j:]
+	return bytes.TrimRight(data[0:i], " \t"), data[j:], j
 }
 
 // removeSpacesAndTabs returns a copy of its input with all spaces and tabs
@@ -90,20 +90,32 @@ func Decode(data []byte) (p *Block, rest []byte) {
 	// pemStart begins with a newline. However, at the very beginning of
 	// the byte array, we'll accept the start string without it.
 	rest = data
+
 	for {
-		if bytes.HasPrefix(rest, pemStart[1:]) {
-			rest = rest[len(pemStart)-1:]
-		} else if _, after, ok := bytes.Cut(rest, pemStart); ok {
-			rest = after
-		} else {
+		// Find the first END line, and then find the last BEGIN line before
+		// the end line. This lets us skip any repeated BEGIN lines that don't
+		// have a matching END.
+		endIndex := bytes.Index(rest, pemEnd)
+		if endIndex < 0 {
+			return nil, data
+		}
+		endTrailerIndex := endIndex + len(pemEnd)
+		beginIndex := bytes.LastIndex(rest[:endIndex], pemStart[1:])
+		if beginIndex < 0 || beginIndex > 0 && rest[beginIndex-1] != '\n' {
 			return nil, data
 		}
+		rest = rest[beginIndex+len(pemStart)-1:]
+		endIndex -= beginIndex + len(pemStart) - 1
+		endTrailerIndex -= beginIndex + len(pemStart) - 1
 
 		var typeLine []byte
-		typeLine, rest = getLine(rest)
+		var consumed int
+		typeLine, rest, consumed = getLine(rest)
 		if !bytes.HasSuffix(typeLine, pemEndOfLine) {
 			continue
 		}
+		endIndex -= consumed
+		endTrailerIndex -= consumed
 		typeLine = typeLine[0 : len(typeLine)-len(pemEndOfLine)]
 
 		p = &Block{
@@ -117,7 +129,7 @@ func Decode(data []byte) (p *Block, rest []byte) {
 			if len(rest) == 0 {
 				return nil, data
 			}
-			line, next := getLine(rest)
+			line, next, consumed := getLine(rest)
 
 			key, val, ok := bytes.Cut(line, colon)
 			if !ok {
@@ -129,21 +141,13 @@ func Decode(data []byte) (p *Block, rest []byte) {
 			val = bytes.TrimSpace(val)
 			p.Headers[string(key)] = string(val)
 			rest = next
+			endIndex -= consumed
+			endTrailerIndex -= consumed
 		}
 
-		var endIndex, endTrailerIndex int
-
-		// If there were no headers, the END line might occur
-		// immediately, without a leading newline.
-		if len(p.Headers) == 0 && bytes.HasPrefix(rest, pemEnd[1:]) {
-			endIndex = 0
-			endTrailerIndex = len(pemEnd) - 1
-		} else {
-			endIndex = bytes.Index(rest, pemEnd)
-			endTrailerIndex = endIndex + len(pemEnd)
-		}
-
-		if endIndex < 0 {
+		// If there were headers, there must be a newline between the headers
+		// and the END line, so endIndex should be >= 0.
+		if len(p.Headers) > 0 && endIndex < 0 {
 			continue
 		}
 
@@ -163,21 +167,24 @@ func Decode(data []byte) (p *Block, rest []byte) {
 		}
 
 		// The line must end with only whitespace.
-		if s, _ := getLine(restOfEndLine); len(s) != 0 {
+		if s, _, _ := getLine(restOfEndLine); len(s) != 0 {
 			continue
 		}
 
-		base64Data := removeSpacesAndTabs(rest[:endIndex])
-		p.Bytes = make([]byte, base64.StdEncoding.DecodedLen(len(base64Data)))
-		n, err := base64.StdEncoding.Decode(p.Bytes, base64Data)
-		if err != nil {
-			continue
+		p.Bytes = []byte{}
+		if endIndex > 0 {
+			base64Data := removeSpacesAndTabs(rest[:endIndex])
+			p.Bytes = make([]byte, base64.StdEncoding.DecodedLen(len(base64Data)))
+			n, err := base64.StdEncoding.Decode(p.Bytes, base64Data)
+			if err != nil {
+				continue
+			}
+			p.Bytes = p.Bytes[:n]
 		}
-		p.Bytes = p.Bytes[:n]
 
 		// the -1 is because we might have only matched pemEnd without the
 		// leading newline if the PEM block was empty.
-		_, rest = getLine(rest[endIndex+len(pemEnd)-1:])
+		_, rest, _ = getLine(rest[endIndex+len(pemEnd)-1:])
 		return p, rest
 	}
 }
diff --git a/src/encoding/pem/pem_test.go b/src/encoding/pem/pem_test.go
index e252ffd8ed1613..2c9b3eabcd1c12 100644
--- a/src/encoding/pem/pem_test.go
+++ b/src/encoding/pem/pem_test.go
@@ -34,7 +34,7 @@ var getLineTests = []GetLineTest{
 
 func TestGetLine(t *testing.T) {
 	for i, test := range getLineTests {
-		x, y := getLine([]byte(test.in))
+		x, y, _ := getLine([]byte(test.in))
 		if string(x) != test.out1 || string(y) != test.out2 {
 			t.Errorf("#%d got:%+v,%+v want:%s,%s", i, x, y, test.out1, test.out2)
 		}
@@ -46,6 +46,7 @@ func TestDecode(t *testing.T) {
 	if !reflect.DeepEqual(result, certificate) {
 		t.Errorf("#0 got:%#v want:%#v", result, certificate)
 	}
+
 	result, remainder = Decode(remainder)
 	if !reflect.DeepEqual(result, privateKey) {
 		t.Errorf("#1 got:%#v want:%#v", result, privateKey)
@@ -68,7 +69,7 @@ func TestDecode(t *testing.T) {
 	}
 
 	result, remainder = Decode(remainder)
-	if result == nil || result.Type != "HEADERS" || len(result.Headers) != 1 {
+	if result == nil || result.Type != "VALID HEADERS" || len(result.Headers) != 1 {
 		t.Errorf("#5 expected single header block but got :%v", result)
 	}
 
@@ -381,15 +382,15 @@ ZWAaUoVtWIQ52aKS0p19G99hhb+IVANC4akkdHV4SP8i7MVNZhfUmg==
 
 # This shouldn't be recognised because of the missing newline after the
 headers.
------BEGIN HEADERS-----
+-----BEGIN INVALID HEADERS-----
 Header: 1
------END HEADERS-----
+-----END INVALID HEADERS-----
 
 # This should be valid, however.
------BEGIN HEADERS-----
+-----BEGIN VALID HEADERS-----
 Header: 1
 
------END HEADERS-----`)
+-----END VALID HEADERS-----`)
 
 var certificate = &Block{Type: "CERTIFICATE",
 	Headers: map[string]string{},

From 5ede095649db7783726c28390812bca9ce2c684a Mon Sep 17 00:00:00 2001
From: Damien Neil 
Date: Tue, 30 Sep 2025 15:11:16 -0700
Subject: [PATCH 087/229] net/textproto: avoid quadratic complexity in
 Reader.ReadResponse

Reader.ReadResponse constructed a response string from repeated
string concatenation, permitting a malicious sender to cause excessive
memory allocation and CPU consumption by sending a response consisting
of many short lines.

Use a strings.Builder to construct the string instead.

Thanks to Jakub Ciolek for reporting this issue.

Fixes CVE-2025-61724
Fixes #75716

Change-Id: I1a98ce85a21b830cb25799f9ac9333a67400d736
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2940
Reviewed-by: Roland Shoemaker 
Reviewed-by: Nicholas Husin 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709859
TryBot-Bypass: Michael Pratt 
Auto-Submit: Michael Pratt 
Reviewed-by: Carlos Amedee 
---
 src/net/textproto/reader.go | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/net/textproto/reader.go b/src/net/textproto/reader.go
index 668c06c24c1372..6df3a630917d78 100644
--- a/src/net/textproto/reader.go
+++ b/src/net/textproto/reader.go
@@ -285,8 +285,10 @@ func (r *Reader) ReadCodeLine(expectCode int) (code int, message string, err err
 //
 // An expectCode <= 0 disables the check of the status code.
 func (r *Reader) ReadResponse(expectCode int) (code int, message string, err error) {
-	code, continued, message, err := r.readCodeLine(expectCode)
+	code, continued, first, err := r.readCodeLine(expectCode)
 	multi := continued
+	var messageBuilder strings.Builder
+	messageBuilder.WriteString(first)
 	for continued {
 		line, err := r.ReadLine()
 		if err != nil {
@@ -297,12 +299,15 @@ func (r *Reader) ReadResponse(expectCode int) (code int, message string, err err
 		var moreMessage string
 		code2, continued, moreMessage, err = parseCodeLine(line, 0)
 		if err != nil || code2 != code {
-			message += "\n" + strings.TrimRight(line, "\r\n")
+			messageBuilder.WriteByte('\n')
+			messageBuilder.WriteString(strings.TrimRight(line, "\r\n"))
 			continued = true
 			continue
 		}
-		message += "\n" + moreMessage
+		messageBuilder.WriteByte('\n')
+		messageBuilder.WriteString(moreMessage)
 	}
+	message = messageBuilder.String()
 	if err != nil && multi && message != "" {
 		// replace one line error message with all lines (full message)
 		err = &Error{code, message}

From 463165699d874ef0ac7965fc5788fe1693eaae9a Mon Sep 17 00:00:00 2001
From: Damien Neil 
Date: Thu, 25 Sep 2025 14:41:53 -0700
Subject: [PATCH 088/229] net/mail: avoid quadratic behavior in mail address
 parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

RFC 5322 domain-literal parsing built the dtext value one character
at a time with string concatenation, resulting in excessive
resource consumption when parsing very large domain-literal values.

Replace with a subslice.

Benchmark not included in this CL because it's too narrow to be
of general ongoing use, but for:

    ParseAddress("alice@[" + strings.Repeat("a", 0x40000) + "]")

goos: darwin
goarch: arm64
pkg: net/mail
cpu: Apple M4 Pro
                │  /tmp/bench.0  │            /tmp/bench.1             │
                │     sec/op     │   sec/op     vs base                │
ParseAddress-14   1987.732m ± 9%   1.524m ± 5%  -99.92% (p=0.000 n=10)

                │   /tmp/bench.0   │             /tmp/bench.1              │
                │       B/op       │     B/op      vs base                 │
ParseAddress-14   33692.767Mi ± 0%   1.282Mi ± 0%  -100.00% (p=0.000 n=10)

                │  /tmp/bench.0  │            /tmp/bench.1            │
                │   allocs/op    │ allocs/op   vs base                │
ParseAddress-14   263711.00 ± 0%   17.00 ± 0%  -99.99% (p=0.000 n=10)

Thanks to Philippe Antoine (Catena cyber) for reporting this issue.

Fixes CVE-2025-61725
Fixes #75680

Change-Id: Id971c2d5b59882bb476e22fceb7e01ec08234bb7
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2840
Reviewed-by: Roland Shoemaker 
Reviewed-by: Nicholas Husin 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709860
Reviewed-by: Carlos Amedee 
TryBot-Bypass: Michael Pratt 
Auto-Submit: Michael Pratt 
---
 src/net/mail/message.go | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/net/mail/message.go b/src/net/mail/message.go
index 14f839a03077c1..1502b3596252ba 100644
--- a/src/net/mail/message.go
+++ b/src/net/mail/message.go
@@ -724,7 +724,8 @@ func (p *addrParser) consumeDomainLiteral() (string, error) {
 	}
 
 	// Parse the dtext
-	var dtext string
+	dtext := p.s
+	dtextLen := 0
 	for {
 		if p.empty() {
 			return "", errors.New("mail: unclosed domain-literal")
@@ -741,9 +742,10 @@ func (p *addrParser) consumeDomainLiteral() (string, error) {
 			return "", fmt.Errorf("mail: bad character in domain-literal: %q", r)
 		}
 
-		dtext += p.s[:size]
+		dtextLen += size
 		p.s = p.s[size:]
 	}
+	dtext = dtext[:dtextLen]
 
 	// Skip the trailing ]
 	if !p.consume(']') {

From f7a68d3804efabd271f0338391858bc1e7e57422 Mon Sep 17 00:00:00 2001
From: Damien Neil 
Date: Thu, 11 Sep 2025 13:32:10 -0700
Subject: [PATCH 089/229] archive/tar: set a limit on the size of GNU sparse
 file 1.0 regions

Sparse files in tar archives contain only the non-zero components
of the file. There are several different encodings for sparse
files. When reading GNU tar pax 1.0 sparse files, archive/tar did
not set a limit on the size of the sparse region data. A malicious
archive containing a large number of sparse blocks could cause
archive/tar to read an unbounded amount of data from the archive
into memory.

Since a malicious input can be highly compressable, a small
compressed input could cause very large allocations.

Cap the size of the sparse block data to the same limit used
for PAX headers (1 MiB).

Thanks to Harshit Gupta (Mr HAX) (https://www.linkedin.com/in/iam-harshit-gupta/)
for reporting this issue.

Fixes CVE-2025-58183
Fixes #75677

Change-Id: I70b907b584a7b8676df8a149a1db728ae681a770
Reviewed-on: https://go-internal-review.googlesource.com/c/go/+/2800
Reviewed-by: Roland Shoemaker 
Reviewed-by: Nicholas Husin 
Reviewed-on: https://go-review.googlesource.com/c/go/+/709861
Auto-Submit: Michael Pratt 
TryBot-Bypass: Michael Pratt 
Reviewed-by: Carlos Amedee 
---
 src/archive/tar/common.go                        |   1 +
 src/archive/tar/reader.go                        |   9 +++++++--
 src/archive/tar/reader_test.go                   |   5 +++++
 .../tar/testdata/gnu-sparse-many-zeros.tar.bz2   | Bin 0 -> 1642 bytes
 4 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 src/archive/tar/testdata/gnu-sparse-many-zeros.tar.bz2

diff --git a/src/archive/tar/common.go b/src/archive/tar/common.go
index 7b3945ff153144..ad31bbb64aaa5c 100644
--- a/src/archive/tar/common.go
+++ b/src/archive/tar/common.go
@@ -39,6 +39,7 @@ var (
 	errMissData        = errors.New("archive/tar: sparse file references non-existent data")
 	errUnrefData       = errors.New("archive/tar: sparse file contains unreferenced data")
 	errWriteHole       = errors.New("archive/tar: write non-NUL byte in sparse hole")
+	errSparseTooLong   = errors.New("archive/tar: sparse map too long")
 )
 
 type headerError []string
diff --git a/src/archive/tar/reader.go b/src/archive/tar/reader.go
index 8483fb52a28f66..16ac2f5b17c28b 100644
--- a/src/archive/tar/reader.go
+++ b/src/archive/tar/reader.go
@@ -531,12 +531,17 @@ func readGNUSparseMap1x0(r io.Reader) (sparseDatas, error) {
 		cntNewline int64
 		buf        bytes.Buffer
 		blk        block
+		totalSize  int
 	)
 
 	// feedTokens copies data in blocks from r into buf until there are
 	// at least cnt newlines in buf. It will not read more blocks than needed.
 	feedTokens := func(n int64) error {
 		for cntNewline < n {
+			totalSize += len(blk)
+			if totalSize > maxSpecialFileSize {
+				return errSparseTooLong
+			}
 			if _, err := mustReadFull(r, blk[:]); err != nil {
 				return err
 			}
@@ -569,8 +574,8 @@ func readGNUSparseMap1x0(r io.Reader) (sparseDatas, error) {
 	}
 
 	// Parse for all member entries.
-	// numEntries is trusted after this since a potential attacker must have
-	// committed resources proportional to what this library used.
+	// numEntries is trusted after this since feedTokens limits the number of
+	// tokens based on maxSpecialFileSize.
 	if err := feedTokens(2 * numEntries); err != nil {
 		return nil, err
 	}
diff --git a/src/archive/tar/reader_test.go b/src/archive/tar/reader_test.go
index 99340a30471914..fca53dae741bd5 100644
--- a/src/archive/tar/reader_test.go
+++ b/src/archive/tar/reader_test.go
@@ -621,6 +621,11 @@ func TestReader(t *testing.T) {
 			},
 			Format: FormatPAX,
 		}},
+	}, {
+		// Small compressed file that uncompresses to
+		// a file with a very large GNU 1.0 sparse map.
+		file: "testdata/gnu-sparse-many-zeros.tar.bz2",
+		err:  errSparseTooLong,
 	}}
 
 	for _, v := range vectors {
diff --git a/src/archive/tar/testdata/gnu-sparse-many-zeros.tar.bz2 b/src/archive/tar/testdata/gnu-sparse-many-zeros.tar.bz2
new file mode 100644
index 0000000000000000000000000000000000000000..751d7fd4b68be1a7439413b4089dbbde33a2900a
GIT binary patch
literal 1642
zcmZ>Y%CIzaj8qGb%wCwXiS2H0{DC_Y9GL$z2|RUTNGrcrz`)SKVZdrPcO01{ps1pvVeGD$*OEWa_73ksV;zBwoQh0BPEH%vtSITeAlMvtlB3E`^y)8{
zw~&+g8{-?Ahs_oW3u(QcHog6FpP~f~~=z-9g
zf_wTZ7^XHZn&-}Zc8R{Fft9C2PEyk*pJkiw?fk^YcK6r>1_p%&1_y>jhFQI$94?0z
za?Cl(nljTjt?TS76W-mu3JeU63=9nnhZs#ILKKBvodhkrxK0|)I$ibrgoSju6wr@N
z42%qnElgP^KzXhfrD74$NvWo@w9QvsFnedxz`)4Dz{J4J!Ez-rpv4zx#WM|Ul~dWe
zujeZ~$i0&Z3?dE&76vu}&J`B}T70wwI?n`zc}}^OvF6@lhub?YF)*+QFmN#NCX1lVw7II6Iq$It1A~AA
zg93v=gRdLVZlD!@quw8l{n5lfn)hi|^v!SyiA^y0F{gnCT=X?DusWMCWpyr3vv&I)
ZCg2!yghOkJkj3svnul7NKE7EI0RUq%CTjoy

literal 0
HcmV?d00001


From f2d0d05d28c3493a8f2b5d4e3c0080e18b9a3bdc Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 19:56:29 -0400
Subject: [PATCH 090/229] cmd/go: refactor usage of `MainModules`

This commit refactors usage of the global variable `MainModules` to
the global LoaderState variable of the same name.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf 'mv State.mainModules State.MainModules'
rf 'ex { MainModules -> LoaderState.MainModules }'
for dir in load modcmd modget test tool workcmd ; do
  cd ../${dir}
  rf 'ex {
    import "cmd/go/internal/modload"
    modload.MainModules -> modload.LoaderState.MainModules
  }'
done
cd ../modload
rf 'rm MainModules'

Change-Id: I15644c84190717d62ae953747a288ec6495ef168
Reviewed-on: https://go-review.googlesource.com/c/go/+/698060
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/load/godebug.go      |  4 +-
 src/cmd/go/internal/load/pkg.go          |  2 +-
 src/cmd/go/internal/load/search.go       |  4 +-
 src/cmd/go/internal/modcmd/download.go   |  6 +-
 src/cmd/go/internal/modcmd/vendor.go     | 20 +++----
 src/cmd/go/internal/modcmd/verify.go     |  2 +-
 src/cmd/go/internal/modget/get.go        | 30 +++++-----
 src/cmd/go/internal/modget/query.go      |  2 +-
 src/cmd/go/internal/modload/build.go     |  4 +-
 src/cmd/go/internal/modload/buildlist.go | 36 ++++++------
 src/cmd/go/internal/modload/edit.go      |  6 +-
 src/cmd/go/internal/modload/import.go    | 30 +++++-----
 src/cmd/go/internal/modload/init.go      | 72 ++++++++++++------------
 src/cmd/go/internal/modload/list.go      |  2 +-
 src/cmd/go/internal/modload/load.go      | 44 +++++++--------
 src/cmd/go/internal/modload/modfile.go   | 36 ++++++------
 src/cmd/go/internal/modload/mvs.go       |  4 +-
 src/cmd/go/internal/modload/query.go     | 28 ++++-----
 src/cmd/go/internal/modload/search.go    | 20 +++----
 src/cmd/go/internal/modload/vendor.go    |  4 +-
 src/cmd/go/internal/test/test.go         |  2 +-
 src/cmd/go/internal/tool/tool.go         |  4 +-
 src/cmd/go/internal/workcmd/sync.go      |  4 +-
 23 files changed, 182 insertions(+), 184 deletions(-)

diff --git a/src/cmd/go/internal/load/godebug.go b/src/cmd/go/internal/load/godebug.go
index ff184384567afe..c795d42f117f0e 100644
--- a/src/cmd/go/internal/load/godebug.go
+++ b/src/cmd/go/internal/load/godebug.go
@@ -49,7 +49,7 @@ func defaultGODEBUG(p *Package, directives, testDirectives, xtestDirectives []bu
 	if p.Name != "main" {
 		return ""
 	}
-	goVersion := modload.MainModules.GoVersion()
+	goVersion := modload.LoaderState.MainModules.GoVersion()
 	if modload.LoaderState.RootMode == modload.NoRoot && p.Module != nil {
 		// This is go install pkg@version or go run pkg@version.
 		// Use the Go version from the package.
@@ -73,7 +73,7 @@ func defaultGODEBUG(p *Package, directives, testDirectives, xtestDirectives []bu
 	}
 
 	// Add directives from main module go.mod.
-	for _, g := range modload.MainModules.Godebugs() {
+	for _, g := range modload.LoaderState.MainModules.Godebugs() {
 		if m == nil {
 			m = make(map[string]string)
 		}
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index 27a1fbfff836fa..135d7579d65dff 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -1552,7 +1552,7 @@ func disallowInternal(ctx context.Context, srcDir string, importer *Package, imp
 			// directory containing them.
 			// If the directory is outside the main modules, this will resolve to ".",
 			// which is not a prefix of any valid module.
-			importerPath, _ = modload.MainModules.DirImportPath(ctx, importer.Dir)
+			importerPath, _ = modload.LoaderState.MainModules.DirImportPath(ctx, importer.Dir)
 		}
 		parentOfInternal := p.ImportPath[:i]
 		if str.HasPathPrefix(importerPath, parentOfInternal) {
diff --git a/src/cmd/go/internal/load/search.go b/src/cmd/go/internal/load/search.go
index 941cfb77a2ec08..51c8cc0932406e 100644
--- a/src/cmd/go/internal/load/search.go
+++ b/src/cmd/go/internal/load/search.go
@@ -56,11 +56,11 @@ func MatchPackage(pattern, cwd string) func(*Package) bool {
 		return func(p *Package) bool { return p.Standard && strings.HasPrefix(p.ImportPath, "cmd/") }
 	case pattern == "tool" && modload.Enabled():
 		return func(p *Package) bool {
-			return modload.MainModules.Tools()[p.ImportPath]
+			return modload.LoaderState.MainModules.Tools()[p.ImportPath]
 		}
 	case pattern == "work" && modload.Enabled():
 		return func(p *Package) bool {
-			return p.Module != nil && modload.MainModules.Contains(p.Module.Path)
+			return p.Module != nil && modload.LoaderState.MainModules.Contains(p.Module.Path)
 		}
 
 	default:
diff --git a/src/cmd/go/internal/modcmd/download.go b/src/cmd/go/internal/modcmd/download.go
index 6d12d689f0ff51..8df11bfa59fa43 100644
--- a/src/cmd/go/internal/modcmd/download.go
+++ b/src/cmd/go/internal/modcmd/download.go
@@ -120,7 +120,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 		modload.LoadModFile(ctx) // to fill MainModules
 
 		if haveExplicitArgs {
-			for _, mainModule := range modload.MainModules.Versions() {
+			for _, mainModule := range modload.LoaderState.MainModules.Versions() {
 				targetAtUpgrade := mainModule.Path + "@upgrade"
 				targetAtPatch := mainModule.Path + "@patch"
 				for _, arg := range args {
@@ -136,8 +136,8 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 			// https://go-review.googlesource.com/c/go/+/359794/comments/ce946a80_6cf53992.
 			args = []string{"all"}
 		} else {
-			mainModule := modload.MainModules.Versions()[0]
-			modFile := modload.MainModules.ModFile(mainModule)
+			mainModule := modload.LoaderState.MainModules.Versions()[0]
+			modFile := modload.LoaderState.MainModules.ModFile(mainModule)
 			if modFile.Go == nil || gover.Compare(modFile.Go.Version, gover.ExplicitIndirectVersion) < 0 {
 				if len(modFile.Require) > 0 {
 					args = []string{"all"}
diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index dfea571c0e0317..df673e885c1473 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -106,7 +106,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 	modpkgs := make(map[module.Version][]string)
 	for _, pkg := range pkgs {
 		m := modload.PackageModule(pkg)
-		if m.Path == "" || modload.MainModules.Contains(m.Path) {
+		if m.Path == "" || modload.LoaderState.MainModules.Contains(m.Path) {
 			continue
 		}
 		modpkgs[m] = append(modpkgs[m], pkg)
@@ -116,13 +116,13 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 	includeAllReplacements := false
 	includeGoVersions := false
 	isExplicit := map[module.Version]bool{}
-	gv := modload.MainModules.GoVersion()
+	gv := modload.LoaderState.MainModules.GoVersion()
 	if gover.Compare(gv, "1.14") >= 0 && (modload.FindGoWork(base.Cwd()) != "" || modload.ModFile().Go != nil) {
 		// If the Go version is at least 1.14, annotate all explicit 'require' and
 		// 'replace' targets found in the go.mod file so that we can perform a
 		// stronger consistency check when -mod=vendor is set.
-		for _, m := range modload.MainModules.Versions() {
-			if modFile := modload.MainModules.ModFile(m); modFile != nil {
+		for _, m := range modload.LoaderState.MainModules.Versions() {
+			if modFile := modload.LoaderState.MainModules.ModFile(m); modFile != nil {
 				for _, r := range modFile.Require {
 					isExplicit[r.Mod] = true
 				}
@@ -156,7 +156,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 		w = io.MultiWriter(&buf, os.Stderr)
 	}
 
-	if modload.MainModules.WorkFile() != nil {
+	if modload.LoaderState.MainModules.WorkFile() != nil {
 		fmt.Fprintf(w, "## workspace\n")
 	}
 
@@ -192,8 +192,8 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 		// Record unused and wildcard replacements at the end of the modules.txt file:
 		// without access to the complete build list, the consumer of the vendor
 		// directory can't otherwise determine that those replacements had no effect.
-		for _, m := range modload.MainModules.Versions() {
-			if workFile := modload.MainModules.WorkFile(); workFile != nil {
+		for _, m := range modload.LoaderState.MainModules.Versions() {
+			if workFile := modload.LoaderState.MainModules.WorkFile(); workFile != nil {
 				for _, r := range workFile.Replace {
 					if replacementWritten[r.Old] {
 						// We already recorded this replacement.
@@ -208,7 +208,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 					}
 				}
 			}
-			if modFile := modload.MainModules.ModFile(m); modFile != nil {
+			if modFile := modload.LoaderState.MainModules.ModFile(m); modFile != nil {
 				for _, r := range modFile.Replace {
 					if replacementWritten[r.Old] {
 						// We already recorded this replacement.
@@ -315,7 +315,7 @@ func vendorPkg(vdir, pkg string) {
 		}
 	}
 	var embedPatterns []string
-	if gover.Compare(modload.MainModules.GoVersion(), "1.22") >= 0 {
+	if gover.Compare(modload.LoaderState.MainModules.GoVersion(), "1.22") >= 0 {
 		embedPatterns = bp.EmbedPatterns
 	} else {
 		// Maintain the behavior of https://github.com/golang/go/issues/63473
@@ -431,7 +431,7 @@ func matchPotentialSourceFile(dir string, info fs.DirEntry) bool {
 		return false
 	}
 	if info.Name() == "go.mod" || info.Name() == "go.sum" {
-		if gv := modload.MainModules.GoVersion(); gover.Compare(gv, "1.17") >= 0 {
+		if gv := modload.LoaderState.MainModules.GoVersion(); gover.Compare(gv, "1.17") >= 0 {
 			// As of Go 1.17, we strip go.mod and go.sum files from dependency modules.
 			// Otherwise, 'go' commands invoked within the vendor subtree may misidentify
 			// an arbitrary directory within the vendor tree as a module root.
diff --git a/src/cmd/go/internal/modcmd/verify.go b/src/cmd/go/internal/modcmd/verify.go
index 157c920c067321..8de444ff06ad1d 100644
--- a/src/cmd/go/internal/modcmd/verify.go
+++ b/src/cmd/go/internal/modcmd/verify.go
@@ -94,7 +94,7 @@ func verifyMod(ctx context.Context, mod module.Version) []error {
 		// "go" and "toolchain" have no disk footprint; nothing to verify.
 		return nil
 	}
-	if modload.MainModules.Contains(mod.Path) {
+	if modload.LoaderState.MainModules.Contains(mod.Path) {
 		return nil
 	}
 	var errs []error
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index 167f515be98a7d..d8b1f83bf1d132 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -426,7 +426,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 
 	if gowork := modload.FindGoWork(base.Cwd()); gowork != "" {
 		wf, err := modload.ReadWorkFile(gowork)
-		if err == nil && modload.UpdateWorkGoVersion(wf, modload.MainModules.GoVersion()) {
+		if err == nil && modload.UpdateWorkGoVersion(wf, modload.LoaderState.MainModules.GoVersion()) {
 			modload.WriteWorkFile(gowork, wf)
 		}
 	}
@@ -722,7 +722,7 @@ func (r *resolver) queryNone(ctx context.Context, q *query) {
 	if !q.isWildcard() {
 		q.pathOnce(q.pattern, func() pathSet {
 			hasModRoot := modload.HasModRoot()
-			if hasModRoot && modload.MainModules.Contains(q.pattern) {
+			if hasModRoot && modload.LoaderState.MainModules.Contains(q.pattern) {
 				v := module.Version{Path: q.pattern}
 				// The user has explicitly requested to downgrade their own module to
 				// version "none". This is not an entirely unreasonable request: it
@@ -746,7 +746,7 @@ func (r *resolver) queryNone(ctx context.Context, q *query) {
 			continue
 		}
 		q.pathOnce(curM.Path, func() pathSet {
-			if modload.HasModRoot() && curM.Version == "" && modload.MainModules.Contains(curM.Path) {
+			if modload.HasModRoot() && curM.Version == "" && modload.LoaderState.MainModules.Contains(curM.Path) {
 				return errSet(&modload.QueryMatchesMainModulesError{MainModules: []module.Version{curM}, Pattern: q.pattern, Query: q.version})
 			}
 			return pathSet{mod: module.Version{Path: curM.Path, Version: "none"}}
@@ -766,13 +766,13 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 
 			// Absolute paths like C:\foo and relative paths like ../foo... are
 			// restricted to matching packages in the main module.
-			pkgPattern, mainModule := modload.MainModules.DirImportPath(ctx, q.pattern)
+			pkgPattern, mainModule := modload.LoaderState.MainModules.DirImportPath(ctx, q.pattern)
 			if pkgPattern == "." {
 				modload.MustHaveModRoot()
-				versions := modload.MainModules.Versions()
+				versions := modload.LoaderState.MainModules.Versions()
 				modRoots := make([]string, 0, len(versions))
 				for _, m := range versions {
-					modRoots = append(modRoots, modload.MainModules.ModRoot(m))
+					modRoots = append(modRoots, modload.LoaderState.MainModules.ModRoot(m))
 				}
 				var plural string
 				if len(modRoots) != 1 {
@@ -792,7 +792,7 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 				}
 				if !q.isWildcard() {
 					modload.MustHaveModRoot()
-					return errSet(fmt.Errorf("%s%s is not a package in module rooted at %s", q.pattern, absDetail, modload.MainModules.ModRoot(mainModule)))
+					return errSet(fmt.Errorf("%s%s is not a package in module rooted at %s", q.pattern, absDetail, modload.LoaderState.MainModules.ModRoot(mainModule)))
 				}
 				search.WarnUnmatched([]*search.Match{match})
 				return pathSet{}
@@ -848,7 +848,7 @@ func (r *resolver) queryWildcard(ctx context.Context, q *query) {
 				return pathSet{}
 			}
 
-			if modload.MainModules.Contains(curM.Path) && !versionOkForMainModule(q.version) {
+			if modload.LoaderState.MainModules.Contains(curM.Path) && !versionOkForMainModule(q.version) {
 				if q.matchesPath(curM.Path) {
 					return errSet(&modload.QueryMatchesMainModulesError{
 						MainModules: []module.Version{curM},
@@ -1065,7 +1065,7 @@ func (r *resolver) queryPath(ctx context.Context, q *query) {
 // pattern is "tool".
 func (r *resolver) performToolQueries(ctx context.Context) {
 	for _, q := range r.toolQueries {
-		for tool := range modload.MainModules.Tools() {
+		for tool := range modload.LoaderState.MainModules.Tools() {
 			q.pathOnce(tool, func() pathSet {
 				pkgMods, err := r.queryPackages(ctx, tool, q.version, r.initialSelected)
 				return pathSet{pkgMods: pkgMods, err: err}
@@ -1082,10 +1082,10 @@ func (r *resolver) performWorkQueries(ctx context.Context) {
 			// TODO(matloob): Maybe export MainModules.mustGetSingleMainModule and call that.
 			// There are a few other places outside the modload package where we expect
 			// a single main module.
-			if len(modload.MainModules.Versions()) != 1 {
+			if len(modload.LoaderState.MainModules.Versions()) != 1 {
 				panic("internal error: number of main modules is not exactly one in resolution phase of go get")
 			}
-			mainModule := modload.MainModules.Versions()[0]
+			mainModule := modload.LoaderState.MainModules.Versions()[0]
 
 			// We know what the result is going to be, assuming the main module is not
 			// empty, (it's the main module itself) but first check to see that there
@@ -1496,7 +1496,7 @@ func (r *resolver) disambiguate(cs pathSet) (filtered pathSet, isPackage bool, m
 			continue
 		}
 
-		if modload.MainModules.Contains(m.Path) {
+		if modload.LoaderState.MainModules.Contains(m.Path) {
 			if m.Version == "" {
 				return pathSet{}, true, m, true
 			}
@@ -1612,7 +1612,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 	// info, but switch back to single module mode when fetching sums so that we update
 	// the single module's go.sum file.
 	var exitWorkspace func()
-	if r.workspace != nil && r.workspace.hasModule(modload.MainModules.Versions()[0].Path) {
+	if r.workspace != nil && r.workspace.hasModule(modload.LoaderState.MainModules.Versions()[0].Path) {
 		var err error
 		exitWorkspace, err = modload.EnterWorkspace(ctx)
 		if err != nil {
@@ -1951,7 +1951,7 @@ func (r *resolver) resolve(q *query, m module.Version) {
 		panic("internal error: resolving a module.Version with an empty path")
 	}
 
-	if modload.MainModules.Contains(m.Path) && m.Version != "" {
+	if modload.LoaderState.MainModules.Contains(m.Path) && m.Version != "" {
 		reportError(q, &modload.QueryMatchesMainModulesError{
 			MainModules: []module.Version{{Path: m.Path}},
 			Pattern:     q.pattern,
@@ -1983,7 +1983,7 @@ func (r *resolver) updateBuildList(ctx context.Context, additions []module.Versi
 
 	resolved := make([]module.Version, 0, len(r.resolvedVersion))
 	for mPath, rv := range r.resolvedVersion {
-		if !modload.MainModules.Contains(mPath) {
+		if !modload.LoaderState.MainModules.Contains(mPath) {
 			resolved = append(resolved, module.Version{Path: mPath, Version: rv.version})
 		}
 	}
diff --git a/src/cmd/go/internal/modget/query.go b/src/cmd/go/internal/modget/query.go
index 05872d52ec4e04..db09947293c6dc 100644
--- a/src/cmd/go/internal/modget/query.go
+++ b/src/cmd/go/internal/modget/query.go
@@ -192,7 +192,7 @@ func (q *query) validate() error {
 			// request that we remove all module requirements, leaving only the main
 			// module and standard library. Perhaps we should implement that someday.
 			return &modload.QueryUpgradesAllError{
-				MainModules: modload.MainModules.Versions(),
+				MainModules: modload.LoaderState.MainModules.Versions(),
 				Query:       q.version,
 			}
 		}
diff --git a/src/cmd/go/internal/modload/build.go b/src/cmd/go/internal/modload/build.go
index 6e30afd5247b36..cb168d58a227bc 100644
--- a/src/cmd/go/internal/modload/build.go
+++ b/src/cmd/go/internal/modload/build.go
@@ -290,7 +290,7 @@ func addDeprecation(ctx context.Context, m *modinfo.ModulePublic) {
 // in rs (which may be nil to indicate that m was not loaded from a requirement
 // graph).
 func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode ListMode, reuse map[module.Version]*modinfo.ModulePublic) *modinfo.ModulePublic {
-	if m.Version == "" && MainModules.Contains(m.Path) {
+	if m.Version == "" && LoaderState.MainModules.Contains(m.Path) {
 		info := &modinfo.ModulePublic{
 			Path:    m.Path,
 			Version: m.Version,
@@ -301,7 +301,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 		} else {
 			panic("internal error: GoVersion not set for main module")
 		}
-		if modRoot := MainModules.ModRoot(m); modRoot != "" {
+		if modRoot := LoaderState.MainModules.ModRoot(m); modRoot != "" {
 			info.Dir = modRoot
 			info.GoMod = modFilePath(modRoot)
 		}
diff --git a/src/cmd/go/internal/modload/buildlist.go b/src/cmd/go/internal/modload/buildlist.go
index 2ba04f707b5472..8afea0b205c4d7 100644
--- a/src/cmd/go/internal/modload/buildlist.go
+++ b/src/cmd/go/internal/modload/buildlist.go
@@ -128,7 +128,7 @@ func newRequirements(pruning modPruning, rootModules []module.Version, direct ma
 			panic("in workspace mode, but pruning is not workspace in newRequirements")
 		}
 		for i, m := range rootModules {
-			if m.Version == "" && MainModules.Contains(m.Path) {
+			if m.Version == "" && LoaderState.MainModules.Contains(m.Path) {
 				panic(fmt.Sprintf("newRequirements called with untrimmed build list: rootModules[%v] is a main module", i))
 			}
 			if m.Path == "" || m.Version == "" {
@@ -174,7 +174,7 @@ func (rs *Requirements) String() string {
 // requirements.
 func (rs *Requirements) initVendor(vendorList []module.Version) {
 	rs.graphOnce.Do(func() {
-		roots := MainModules.Versions()
+		roots := LoaderState.MainModules.Versions()
 		if inWorkspaceMode() {
 			// Use rs.rootModules to pull in the go and toolchain roots
 			// from the go.work file and preserve the invariant that all
@@ -186,7 +186,7 @@ func (rs *Requirements) initVendor(vendorList []module.Version) {
 		}
 
 		if rs.pruning == pruned {
-			mainModule := MainModules.mustGetSingleMainModule()
+			mainModule := LoaderState.MainModules.mustGetSingleMainModule()
 			// The roots of a single pruned module should already include every module in the
 			// vendor list, because the vendored modules are the same as those needed
 			// for graph pruning.
@@ -219,14 +219,14 @@ func (rs *Requirements) initVendor(vendorList []module.Version) {
 			// dependencies.
 			vendorMod := module.Version{Path: "vendor/modules.txt", Version: ""}
 			if inWorkspaceMode() {
-				for _, m := range MainModules.Versions() {
-					reqs, _ := rootsFromModFile(m, MainModules.ModFile(m), omitToolchainRoot)
+				for _, m := range LoaderState.MainModules.Versions() {
+					reqs, _ := rootsFromModFile(m, LoaderState.MainModules.ModFile(m), omitToolchainRoot)
 					mg.g.Require(m, append(reqs, vendorMod))
 				}
 				mg.g.Require(vendorMod, vendorList)
 
 			} else {
-				mainModule := MainModules.mustGetSingleMainModule()
+				mainModule := LoaderState.MainModules.mustGetSingleMainModule()
 				mg.g.Require(mainModule, append(rs.rootModules, vendorMod))
 				mg.g.Require(vendorMod, vendorList)
 			}
@@ -249,7 +249,7 @@ func (rs *Requirements) GoVersion() string {
 // path, or the zero module.Version and ok=false if the module is not a root
 // dependency.
 func (rs *Requirements) rootSelected(path string) (version string, ok bool) {
-	if MainModules.Contains(path) {
+	if LoaderState.MainModules.Contains(path) {
 		return "", true
 	}
 	if v, ok := rs.maxRootVersion[path]; ok {
@@ -264,7 +264,7 @@ func (rs *Requirements) rootSelected(path string) (version string, ok bool) {
 // selection.
 func (rs *Requirements) hasRedundantRoot() bool {
 	for i, m := range rs.rootModules {
-		if MainModules.Contains(m.Path) || (i > 0 && m.Path == rs.rootModules[i-1].Path) {
+		if LoaderState.MainModules.Contains(m.Path) || (i > 0 && m.Path == rs.rootModules[i-1].Path) {
 			return true
 		}
 	}
@@ -346,7 +346,7 @@ func readModGraph(ctx context.Context, pruning modPruning, roots []module.Versio
 	if inWorkspaceMode() {
 		graphRoots = roots
 	} else {
-		graphRoots = MainModules.Versions()
+		graphRoots = LoaderState.MainModules.Versions()
 	}
 	var (
 		mu       sync.Mutex // guards mg.g and hasError during loading
@@ -360,7 +360,7 @@ func readModGraph(ctx context.Context, pruning modPruning, roots []module.Versio
 		if inWorkspaceMode() {
 			panic("pruning is not workspace in workspace mode")
 		}
-		mg.g.Require(MainModules.mustGetSingleMainModule(), roots)
+		mg.g.Require(LoaderState.MainModules.mustGetSingleMainModule(), roots)
 	}
 
 	type dedupKey struct {
@@ -540,9 +540,9 @@ func (mg *ModuleGraph) findError() error {
 func (mg *ModuleGraph) allRootsSelected() bool {
 	var roots []module.Version
 	if inWorkspaceMode() {
-		roots = MainModules.Versions()
+		roots = LoaderState.MainModules.Versions()
 	} else {
-		roots, _ = mg.g.RequiredBy(MainModules.mustGetSingleMainModule())
+		roots, _ = mg.g.RequiredBy(LoaderState.MainModules.mustGetSingleMainModule())
 	}
 	for _, m := range roots {
 		if mg.Selected(m.Path) != m.Version {
@@ -776,7 +776,7 @@ func (c Conflict) String() string {
 // both retain the same versions of all packages in pkgs and satisfy the
 // graph-pruning invariants (if applicable).
 func tidyRoots(ctx context.Context, rs *Requirements, pkgs []*loadPkg) (*Requirements, error) {
-	mainModule := MainModules.mustGetSingleMainModule()
+	mainModule := LoaderState.MainModules.mustGetSingleMainModule()
 	if rs.pruning == unpruned {
 		return tidyUnprunedRoots(ctx, mainModule, rs, pkgs)
 	}
@@ -1168,7 +1168,7 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 		roots = make([]module.Version, 0, len(rs.rootModules))
 		rootsUpgraded = false
 		inRootPaths := make(map[string]bool, len(rs.rootModules)+1)
-		for _, mm := range MainModules.Versions() {
+		for _, mm := range LoaderState.MainModules.Versions() {
 			inRootPaths[mm.Path] = true
 		}
 		for _, m := range rs.rootModules {
@@ -1445,7 +1445,7 @@ func updateUnprunedRoots(ctx context.Context, direct map[string]bool, rs *Requir
 	// This is only for convenience and clarity for end users: in an unpruned module,
 	// the choice of explicit vs. implicit dependency has no impact on MVS
 	// selection (for itself or any other module).
-	keep := append(mg.BuildList()[MainModules.Len():], add...)
+	keep := append(mg.BuildList()[LoaderState.MainModules.Len():], add...)
 	for _, m := range keep {
 		if direct[m.Path] && !inRootPaths[m.Path] {
 			rootPaths = append(rootPaths, m.Path)
@@ -1454,14 +1454,14 @@ func updateUnprunedRoots(ctx context.Context, direct map[string]bool, rs *Requir
 	}
 
 	var roots []module.Version
-	for _, mainModule := range MainModules.Versions() {
+	for _, mainModule := range LoaderState.MainModules.Versions() {
 		min, err := mvs.Req(mainModule, rootPaths, &mvsReqs{roots: keep})
 		if err != nil {
 			return rs, err
 		}
 		roots = append(roots, min...)
 	}
-	if MainModules.Len() > 1 {
+	if LoaderState.MainModules.Len() > 1 {
 		gover.ModSort(roots)
 	}
 	if rs.pruning == unpruned && slices.Equal(roots, rs.rootModules) && maps.Equal(direct, rs.direct) {
@@ -1501,5 +1501,5 @@ func convertPruning(ctx context.Context, rs *Requirements, pruning modPruning) (
 	if err != nil {
 		return rs, err
 	}
-	return newRequirements(pruned, mg.BuildList()[MainModules.Len():], rs.direct), nil
+	return newRequirements(pruned, mg.BuildList()[LoaderState.MainModules.Len():], rs.direct), nil
 }
diff --git a/src/cmd/go/internal/modload/edit.go b/src/cmd/go/internal/modload/edit.go
index b406193dc5a673..153c21a90cc423 100644
--- a/src/cmd/go/internal/modload/edit.go
+++ b/src/cmd/go/internal/modload/edit.go
@@ -106,7 +106,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 			// to begin with, so we can't edit those requirements in a coherent way.
 			return orig, false, err
 		}
-		bl := mg.BuildList()[MainModules.Len():]
+		bl := mg.BuildList()[LoaderState.MainModules.Len():]
 		selectedRoot = make(map[string]string, len(bl))
 		for _, m := range bl {
 			selectedRoot[m.Path] = m.Version
@@ -513,7 +513,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 
 		// The modules in mustSelect are always promoted to be explicit.
 		for _, m := range mustSelect {
-			if m.Version != "none" && !MainModules.Contains(m.Path) {
+			if m.Version != "none" && !LoaderState.MainModules.Contains(m.Path) {
 				rootPaths = append(rootPaths, m.Path)
 			}
 		}
@@ -530,7 +530,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 			}
 		}
 
-		roots, err = mvs.Req(MainModules.mustGetSingleMainModule(), rootPaths, &mvsReqs{roots: roots})
+		roots, err = mvs.Req(LoaderState.MainModules.mustGetSingleMainModule(), rootPaths, &mvsReqs{roots: roots})
 		if err != nil {
 			return nil, false, err
 		}
diff --git a/src/cmd/go/internal/modload/import.go b/src/cmd/go/internal/modload/import.go
index 171d9d692fbb82..83e7e037117a4d 100644
--- a/src/cmd/go/internal/modload/import.go
+++ b/src/cmd/go/internal/modload/import.go
@@ -82,8 +82,8 @@ func (e *ImportMissingError) Error() string {
 		if e.QueryErr != nil {
 			return fmt.Sprintf("%s: %v", message, e.QueryErr)
 		}
-		if e.ImportingMainModule.Path != "" && e.ImportingMainModule != MainModules.ModContainingCWD() {
-			return fmt.Sprintf("%s; to add it:\n\tcd %s\n\tgo get %s", message, MainModules.ModRoot(e.ImportingMainModule), e.Path)
+		if e.ImportingMainModule.Path != "" && e.ImportingMainModule != LoaderState.MainModules.ModContainingCWD() {
+			return fmt.Sprintf("%s; to add it:\n\tcd %s\n\tgo get %s", message, LoaderState.MainModules.ModRoot(e.ImportingMainModule), e.Path)
 		}
 		return fmt.Sprintf("%s; to add it:\n\tgo get %s", message, e.Path)
 	}
@@ -299,12 +299,12 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 	// Is the package in the standard library?
 	pathIsStd := search.IsStandardImportPath(path)
 	if pathIsStd && modindex.IsStandardPackage(cfg.GOROOT, cfg.BuildContext.Compiler, path) {
-		for _, mainModule := range MainModules.Versions() {
-			if MainModules.InGorootSrc(mainModule) {
-				if dir, ok, err := dirInModule(path, MainModules.PathPrefix(mainModule), MainModules.ModRoot(mainModule), true); err != nil {
-					return module.Version{}, MainModules.ModRoot(mainModule), dir, nil, err
+		for _, mainModule := range LoaderState.MainModules.Versions() {
+			if LoaderState.MainModules.InGorootSrc(mainModule) {
+				if dir, ok, err := dirInModule(path, LoaderState.MainModules.PathPrefix(mainModule), LoaderState.MainModules.ModRoot(mainModule), true); err != nil {
+					return module.Version{}, LoaderState.MainModules.ModRoot(mainModule), dir, nil, err
 				} else if ok {
-					return mainModule, MainModules.ModRoot(mainModule), dir, nil, nil
+					return mainModule, LoaderState.MainModules.ModRoot(mainModule), dir, nil, nil
 				}
 			}
 		}
@@ -321,10 +321,10 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 	// Everything must be in the main modules or the main module's or workspace's vendor directory.
 	if cfg.BuildMod == "vendor" {
 		var mainErr error
-		for _, mainModule := range MainModules.Versions() {
-			modRoot := MainModules.ModRoot(mainModule)
+		for _, mainModule := range LoaderState.MainModules.Versions() {
+			modRoot := LoaderState.MainModules.ModRoot(mainModule)
 			if modRoot != "" {
-				dir, mainOK, err := dirInModule(path, MainModules.PathPrefix(mainModule), modRoot, true)
+				dir, mainOK, err := dirInModule(path, LoaderState.MainModules.PathPrefix(mainModule), modRoot, true)
 				if mainErr == nil {
 					mainErr = err
 				}
@@ -345,7 +345,7 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 				// vendor/modules.txt does not exist or the user manually added directories to the vendor directory.
 				// Go 1.23 and later require vendored packages to be present in modules.txt to be imported.
 				_, ok := vendorPkgModule[path]
-				if ok || (gover.Compare(MainModules.GoVersion(), gover.ExplicitModulesTxtImportVersion) < 0) {
+				if ok || (gover.Compare(LoaderState.MainModules.GoVersion(), gover.ExplicitModulesTxtImportVersion) < 0) {
 					mods = append(mods, vendorPkgModule[path])
 					dirs = append(dirs, dir)
 					roots = append(roots, vendorDir)
@@ -471,7 +471,7 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 			// If the module graph is pruned and this is a test-only dependency
 			// of a package in "all", we didn't necessarily load that file
 			// when we read the module graph, so do it now to be sure.
-			if !skipModFile && cfg.BuildMod != "vendor" && mods[0].Path != "" && !MainModules.Contains(mods[0].Path) {
+			if !skipModFile && cfg.BuildMod != "vendor" && mods[0].Path != "" && !LoaderState.MainModules.Contains(mods[0].Path) {
 				if _, err := goModSummary(mods[0]); err != nil {
 					return module.Version{}, "", "", nil, err
 				}
@@ -511,8 +511,8 @@ func queryImport(ctx context.Context, path string, rs *Requirements) (module.Ver
 	// To avoid spurious remote fetches, try the latest replacement for each
 	// module (golang.org/issue/26241).
 	var mods []module.Version
-	if MainModules != nil { // TODO(#48912): Ensure MainModules exists at this point, and remove the check.
-		for mp, mv := range MainModules.HighestReplaced() {
+	if LoaderState.MainModules != nil { // TODO(#48912): Ensure MainModules exists at this point, and remove the check.
+		for mp, mv := range LoaderState.MainModules.HighestReplaced() {
 			if !maybeInModule(path, mp) {
 				continue
 			}
@@ -748,7 +748,7 @@ func dirInModule(path, mpath, mdir string, isLocal bool) (dir string, haveGoFile
 // The isLocal return value reports whether the replacement,
 // if any, is local to the filesystem.
 func fetch(ctx context.Context, mod module.Version) (dir string, isLocal bool, err error) {
-	if modRoot := MainModules.ModRoot(mod); modRoot != "" {
+	if modRoot := LoaderState.MainModules.ModRoot(mod); modRoot != "" {
 		return modRoot, true, nil
 	}
 	if r := Replacement(mod); r.Path != "" {
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index dc0d78499b9cd0..28f55a621d60de 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -58,7 +58,7 @@ var (
 
 // EnterModule resets MainModules and requirements to refer to just this one module.
 func EnterModule(ctx context.Context, enterModroot string) {
-	MainModules = nil // reset MainModules
+	LoaderState.MainModules = nil // reset MainModules
 	requirements = nil
 	workFilePath = "" // Force module mode
 	modfetch.Reset()
@@ -73,7 +73,7 @@ func EnterModule(ctx context.Context, enterModroot string) {
 // EnterWorkspace will modify the global state they depend on in a non-thread-safe way.
 func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	// Find the identity of the main module that will be updated before we reset modload state.
-	mm := MainModules.mustGetSingleMainModule()
+	mm := LoaderState.MainModules.mustGetSingleMainModule()
 	// Get the updated modfile we will use for that module.
 	_, _, updatedmodfile, err := UpdateGoModFromReqs(ctx, WriteOpts{})
 	if err != nil {
@@ -89,8 +89,8 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	LoadModFile(ctx)
 
 	// Update the content of the previous main module, and recompute the requirements.
-	*MainModules.ModFile(mm) = *updatedmodfile
-	requirements = requirementsFromModFiles(ctx, MainModules.workFile, slices.Collect(maps.Values(MainModules.modFiles)), nil)
+	*LoaderState.MainModules.ModFile(mm) = *updatedmodfile
+	requirements = requirementsFromModFiles(ctx, LoaderState.MainModules.workFile, slices.Collect(maps.Values(LoaderState.MainModules.modFiles)), nil)
 
 	return func() {
 		setState(oldstate)
@@ -294,8 +294,6 @@ func (mms *MainModuleSet) WorkFileReplaceMap() map[module.Version]module.Version
 	return mms.workFileReplaceMap
 }
 
-var MainModules *MainModuleSet
-
 type Root int
 
 const (
@@ -324,7 +322,7 @@ const (
 // in go.mod, edit it before loading.
 func ModFile() *modfile.File {
 	Init()
-	modFile := MainModules.ModFile(MainModules.mustGetSingleMainModule())
+	modFile := LoaderState.MainModules.ModFile(LoaderState.MainModules.mustGetSingleMainModule())
 	if modFile == nil {
 		die()
 	}
@@ -396,7 +394,7 @@ func setState(s State) State {
 		RootMode:        LoaderState.RootMode,
 		modRoots:        LoaderState.modRoots,
 		modulesEnabled:  cfg.ModulesEnabled,
-		mainModules:     MainModules,
+		MainModules:     LoaderState.MainModules,
 		requirements:    requirements,
 	}
 	LoaderState.initialized = s.initialized
@@ -404,7 +402,7 @@ func setState(s State) State {
 	LoaderState.RootMode = s.RootMode
 	LoaderState.modRoots = s.modRoots
 	cfg.ModulesEnabled = s.modulesEnabled
-	MainModules = s.mainModules
+	LoaderState.MainModules = s.MainModules
 	requirements = s.requirements
 	workFilePath = s.workFilePath
 	// The modfetch package's global state is used to compute
@@ -431,7 +429,7 @@ type State struct {
 	// modRoots != nil implies len(modRoots) > 0
 	modRoots       []string
 	modulesEnabled bool
-	mainModules    *MainModuleSet
+	MainModules    *MainModuleSet
 	requirements   *Requirements
 	workFilePath   string
 	modfetchState  modfetch.State
@@ -628,7 +626,7 @@ func VendorDir() string {
 	// Even if -mod=vendor, we could be operating with no mod root (and thus no
 	// vendor directory). As long as there are no dependencies that is expected
 	// to work. See script/vendor_outside_module.txt.
-	modRoot := MainModules.ModRoot(MainModules.mustGetSingleMainModule())
+	modRoot := LoaderState.MainModules.ModRoot(LoaderState.MainModules.mustGetSingleMainModule())
 	if modRoot == "" {
 		panic("vendor directory does not exist when in single module mode outside of a module")
 	}
@@ -914,7 +912,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		// make MainModules.Len() == 0 mean that we're in module mode but not inside
 		// any module.
 		mainModule := module.Version{Path: "command-line-arguments"}
-		MainModules = makeMainModules([]module.Version{mainModule}, []string{""}, []*modfile.File{nil}, []*modFileIndex{nil}, nil)
+		LoaderState.MainModules = makeMainModules([]module.Version{mainModule}, []string{""}, []*modfile.File{nil}, []*modFileIndex{nil}, nil)
 		var (
 			goVersion string
 			pruning   modPruning
@@ -925,7 +923,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			// Since we are in a workspace, the Go version for the synthetic
 			// "command-line-arguments" module must not exceed the Go version
 			// for the workspace.
-			goVersion = MainModules.GoVersion()
+			goVersion = LoaderState.MainModules.GoVersion()
 			pruning = workspace
 			roots = []module.Version{
 				mainModule,
@@ -1016,20 +1014,20 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		return nil, errors.Join(errs...)
 	}
 
-	MainModules = makeMainModules(mainModules, LoaderState.modRoots, modFiles, indices, workFile)
+	LoaderState.MainModules = makeMainModules(mainModules, LoaderState.modRoots, modFiles, indices, workFile)
 	setDefaultBuildMod() // possibly enable automatic vendoring
 	rs := requirementsFromModFiles(ctx, workFile, modFiles, opts)
 
 	if cfg.BuildMod == "vendor" {
 		readVendorList(VendorDir())
-		versions := MainModules.Versions()
+		versions := LoaderState.MainModules.Versions()
 		indexes := make([]*modFileIndex, 0, len(versions))
 		modFiles := make([]*modfile.File, 0, len(versions))
 		modRoots := make([]string, 0, len(versions))
 		for _, m := range versions {
-			indexes = append(indexes, MainModules.Index(m))
-			modFiles = append(modFiles, MainModules.ModFile(m))
-			modRoots = append(modRoots, MainModules.ModRoot(m))
+			indexes = append(indexes, LoaderState.MainModules.Index(m))
+			modFiles = append(modFiles, LoaderState.MainModules.ModFile(m))
+			modRoots = append(modRoots, LoaderState.MainModules.ModRoot(m))
 		}
 		checkVendorConsistency(indexes, modFiles, modRoots)
 		rs.initVendor(vendorList)
@@ -1041,7 +1039,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		return rs, nil
 	}
 
-	mainModule := MainModules.mustGetSingleMainModule()
+	mainModule := LoaderState.MainModules.mustGetSingleMainModule()
 
 	if rs.hasRedundantRoot() {
 		// If any module path appears more than once in the roots, we know that the
@@ -1054,7 +1052,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		}
 	}
 
-	if MainModules.Index(mainModule).goVersion == "" && rs.pruning != workspace {
+	if LoaderState.MainModules.Index(mainModule).goVersion == "" && rs.pruning != workspace {
 		// TODO(#45551): Do something more principled instead of checking
 		// cfg.CmdName directly here.
 		if cfg.BuildMod == "mod" && cfg.CmdName != "mod graph" && cfg.CmdName != "mod why" {
@@ -1063,7 +1061,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			if opts != nil && opts.TidyGoVersion != "" {
 				v = opts.TidyGoVersion
 			}
-			addGoStmt(MainModules.ModFile(mainModule), mainModule, v)
+			addGoStmt(LoaderState.MainModules.ModFile(mainModule), mainModule, v)
 			rs = overrideRoots(ctx, rs, []module.Version{{Path: "go", Version: v}})
 
 			// We need to add a 'go' version to the go.mod file, but we must assume
@@ -1156,7 +1154,7 @@ func CreateModFile(ctx context.Context, modPath string) {
 	fmt.Fprintf(os.Stderr, "go: creating new go.mod: module %s\n", modPath)
 	modFile := new(modfile.File)
 	modFile.AddModuleStmt(modPath)
-	MainModules = makeMainModules([]module.Version{modFile.Module.Mod}, []string{modRoot}, []*modfile.File{modFile}, []*modFileIndex{nil}, nil)
+	LoaderState.MainModules = makeMainModules([]module.Version{modFile.Module.Mod}, []string{modRoot}, []*modfile.File{modFile}, []*modFileIndex{nil}, nil)
 	addGoStmt(modFile, modFile.Module.Mod, gover.Local()) // Add the go directive before converted module requirements.
 
 	rs := requirementsFromModFiles(ctx, nil, []*modfile.File{modFile}, nil)
@@ -1380,8 +1378,8 @@ func requirementsFromModFiles(ctx context.Context, workFile *modfile.WorkFile, m
 	var pruning modPruning
 	if inWorkspaceMode() {
 		pruning = workspace
-		roots = make([]module.Version, len(MainModules.Versions()), 2+len(MainModules.Versions()))
-		copy(roots, MainModules.Versions())
+		roots = make([]module.Version, len(LoaderState.MainModules.Versions()), 2+len(LoaderState.MainModules.Versions()))
+		copy(roots, LoaderState.MainModules.Versions())
 		goVersion := gover.FromGoWork(workFile)
 		var toolchain string
 		if workFile.Toolchain != nil {
@@ -1390,12 +1388,12 @@ func requirementsFromModFiles(ctx context.Context, workFile *modfile.WorkFile, m
 		roots = appendGoAndToolchainRoots(roots, goVersion, toolchain, direct)
 		direct = directRequirements(modFiles)
 	} else {
-		pruning = pruningForGoVersion(MainModules.GoVersion())
+		pruning = pruningForGoVersion(LoaderState.MainModules.GoVersion())
 		if len(modFiles) != 1 {
 			panic(fmt.Errorf("requirementsFromModFiles called with %v modfiles outside workspace mode", len(modFiles)))
 		}
 		modFile := modFiles[0]
-		roots, direct = rootsFromModFile(MainModules.mustGetSingleMainModule(), modFile, withToolchainRoot)
+		roots, direct = rootsFromModFile(LoaderState.MainModules.mustGetSingleMainModule(), modFile, withToolchainRoot)
 	}
 
 	gover.ModSort(roots)
@@ -1430,7 +1428,7 @@ func rootsFromModFile(m module.Version, modFile *modfile.File, addToolchainRoot
 	}
 	roots = make([]module.Version, 0, padding+len(modFile.Require))
 	for _, r := range modFile.Require {
-		if index := MainModules.Index(m); index != nil && index.exclude[r.Mod] {
+		if index := LoaderState.MainModules.Index(m); index != nil && index.exclude[r.Mod] {
 			if cfg.BuildMod == "mod" {
 				fmt.Fprintf(os.Stderr, "go: dropping requirement on excluded version %s %s\n", r.Mod.Path, r.Mod.Version)
 			} else {
@@ -1522,12 +1520,12 @@ func setDefaultBuildMod() {
 		var versionSource string
 		if inWorkspaceMode() {
 			versionSource = "go.work"
-			if wfg := MainModules.WorkFile().Go; wfg != nil {
+			if wfg := LoaderState.MainModules.WorkFile().Go; wfg != nil {
 				goVersion = wfg.Version
 			}
 		} else {
 			versionSource = "go.mod"
-			index := MainModules.GetSingleIndexOrNil()
+			index := LoaderState.MainModules.GetSingleIndexOrNil()
 			if index != nil {
 				goVersion = index.goVersion
 			}
@@ -1812,12 +1810,12 @@ var errNoChange = errors.New("no update needed")
 // UpdateGoModFromReqs returns a modified go.mod file using the current
 // requirements. It does not commit these changes to disk.
 func UpdateGoModFromReqs(ctx context.Context, opts WriteOpts) (before, after []byte, modFile *modfile.File, err error) {
-	if MainModules.Len() != 1 || MainModules.ModRoot(MainModules.Versions()[0]) == "" {
+	if LoaderState.MainModules.Len() != 1 || LoaderState.MainModules.ModRoot(LoaderState.MainModules.Versions()[0]) == "" {
 		// We aren't in a module, so we don't have anywhere to write a go.mod file.
 		return nil, nil, nil, errNoChange
 	}
-	mainModule := MainModules.mustGetSingleMainModule()
-	modFile = MainModules.ModFile(mainModule)
+	mainModule := LoaderState.MainModules.mustGetSingleMainModule()
+	modFile = LoaderState.MainModules.ModFile(mainModule)
 	if modFile == nil {
 		// command-line-arguments has no .mod file to write.
 		return nil, nil, nil, errNoChange
@@ -1925,7 +1923,7 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 		return err
 	}
 
-	index := MainModules.GetSingleIndexOrNil()
+	index := LoaderState.MainModules.GetSingleIndexOrNil()
 	dirty := index.modFileIsDirty(modFile) || len(opts.DropTools) > 0 || len(opts.AddTools) > 0
 	if dirty && cfg.BuildMod != "mod" {
 		// If we're about to fail due to -mod=readonly,
@@ -1946,8 +1944,8 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 		return nil
 	}
 
-	mainModule := MainModules.mustGetSingleMainModule()
-	modFilePath := modFilePath(MainModules.ModRoot(mainModule))
+	mainModule := LoaderState.MainModules.mustGetSingleMainModule()
+	modFilePath := modFilePath(LoaderState.MainModules.ModRoot(mainModule))
 	if fsys.Replaced(modFilePath) {
 		if dirty {
 			return errors.New("updates to go.mod needed, but go.mod is part of the overlay specified with -overlay")
@@ -1956,7 +1954,7 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 	}
 	defer func() {
 		// At this point we have determined to make the go.mod file on disk equal to new.
-		MainModules.SetIndex(mainModule, indexModFile(updatedGoMod, modFile, mainModule, false))
+		LoaderState.MainModules.SetIndex(mainModule, indexModFile(updatedGoMod, modFile, mainModule, false))
 
 		// Update go.sum after releasing the side lock and refreshing the index.
 		// 'go mod init' shouldn't write go.sum, since it will be incomplete.
@@ -2018,7 +2016,7 @@ func keepSums(ctx context.Context, ld *loader, rs *Requirements, which whichSums
 	// ambiguous import errors the next time we load the package.
 	keepModSumsForZipSums := true
 	if ld == nil {
-		if gover.Compare(MainModules.GoVersion(), gover.TidyGoModSumVersion) < 0 && cfg.BuildMod != "mod" {
+		if gover.Compare(LoaderState.MainModules.GoVersion(), gover.TidyGoModSumVersion) < 0 && cfg.BuildMod != "mod" {
 			keepModSumsForZipSums = false
 		}
 	} else {
diff --git a/src/cmd/go/internal/modload/list.go b/src/cmd/go/internal/modload/list.go
index 53cb6c2ffe1406..b2d071dcf69723 100644
--- a/src/cmd/go/internal/modload/list.go
+++ b/src/cmd/go/internal/modload/list.go
@@ -126,7 +126,7 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 func listModules(ctx context.Context, rs *Requirements, args []string, mode ListMode, reuse map[module.Version]*modinfo.ModulePublic) (_ *Requirements, mods []*modinfo.ModulePublic, mgErr error) {
 	if len(args) == 0 {
 		var ms []*modinfo.ModulePublic
-		for _, m := range MainModules.Versions() {
+		for _, m := range LoaderState.MainModules.Versions() {
 			if gover.IsToolchain(m.Path) {
 				continue
 			}
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index 7fba712f952e2a..54e1da902cfd00 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -273,7 +273,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 				if m.Dirs == nil {
 					matchModRoots := LoaderState.modRoots
 					if opts.MainModule != (module.Version{}) {
-						matchModRoots = []string{MainModules.ModRoot(opts.MainModule)}
+						matchModRoots = []string{LoaderState.MainModules.ModRoot(opts.MainModule)}
 					}
 					matchLocalDirs(ctx, matchModRoots, m, rs)
 				}
@@ -324,7 +324,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 				matchPackages(ctx, m, opts.Tags, includeStd, mg.BuildList())
 
 			case m.Pattern() == "work":
-				matchModules := MainModules.Versions()
+				matchModules := LoaderState.MainModules.Versions()
 				if opts.MainModule != (module.Version{}) {
 					matchModules = []module.Version{opts.MainModule}
 				}
@@ -335,12 +335,12 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 					// The initial roots are the packages and tools in the main module.
 					// loadFromRoots will expand that to "all".
 					m.Errs = m.Errs[:0]
-					matchModules := MainModules.Versions()
+					matchModules := LoaderState.MainModules.Versions()
 					if opts.MainModule != (module.Version{}) {
 						matchModules = []module.Version{opts.MainModule}
 					}
 					matchPackages(ctx, m, opts.Tags, omitStd, matchModules)
-					for tool := range MainModules.Tools() {
+					for tool := range LoaderState.MainModules.Tools() {
 						m.Pkgs = append(m.Pkgs, tool)
 					}
 				} else {
@@ -355,7 +355,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 				}
 
 			case m.Pattern() == "tool":
-				for tool := range MainModules.Tools() {
+				for tool := range LoaderState.MainModules.Tools() {
 					m.Pkgs = append(m.Pkgs, tool)
 				}
 			default:
@@ -596,13 +596,13 @@ func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (str
 		}
 	}
 
-	for _, mod := range MainModules.Versions() {
-		modRoot := MainModules.ModRoot(mod)
+	for _, mod := range LoaderState.MainModules.Versions() {
+		modRoot := LoaderState.MainModules.ModRoot(mod)
 		if modRoot != "" && absDir == modRoot {
 			if absDir == cfg.GOROOTsrc {
 				return "", errPkgIsGorootSrc
 			}
-			return MainModules.PathPrefix(mod), nil
+			return LoaderState.MainModules.PathPrefix(mod), nil
 		}
 	}
 
@@ -611,8 +611,8 @@ func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (str
 	// It's not strictly necessary but helpful to keep the checks.
 	var pkgNotFoundErr error
 	pkgNotFoundLongestPrefix := ""
-	for _, mainModule := range MainModules.Versions() {
-		modRoot := MainModules.ModRoot(mainModule)
+	for _, mainModule := range LoaderState.MainModules.Versions() {
+		modRoot := LoaderState.MainModules.ModRoot(mainModule)
 		if modRoot != "" && str.HasFilePathPrefix(absDir, modRoot) && !strings.Contains(absDir[len(modRoot):], "@") {
 			suffix := filepath.ToSlash(str.TrimFilePathPrefix(absDir, modRoot))
 			if pkg, found := strings.CutPrefix(suffix, "vendor/"); found {
@@ -627,7 +627,7 @@ func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (str
 				return pkg, nil
 			}
 
-			mainModulePrefix := MainModules.PathPrefix(mainModule)
+			mainModulePrefix := LoaderState.MainModules.PathPrefix(mainModule)
 			if mainModulePrefix == "" {
 				pkg := suffix
 				if pkg == "builtin" {
@@ -820,7 +820,7 @@ func (mms *MainModuleSet) DirImportPath(ctx context.Context, dir string) (path s
 			return mms.PathPrefix(v), v
 		}
 		if str.HasFilePathPrefix(dir, modRoot) {
-			pathPrefix := MainModules.PathPrefix(v)
+			pathPrefix := LoaderState.MainModules.PathPrefix(v)
 			if pathPrefix > longestPrefix {
 				longestPrefix = pathPrefix
 				longestPrefixVersion = v
@@ -1068,7 +1068,7 @@ func (pkg *loadPkg) fromExternalModule() bool {
 	if pkg.mod.Path == "" {
 		return false // loaded from the standard library, not a module
 	}
-	return !MainModules.Contains(pkg.mod.Path)
+	return !LoaderState.MainModules.Contains(pkg.mod.Path)
 }
 
 var errMissing = errors.New("cannot find package")
@@ -1390,7 +1390,7 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 				}
 			}
 		}
-		if pkg.mod.Version != "" || !MainModules.Contains(pkg.mod.Path) {
+		if pkg.mod.Version != "" || !LoaderState.MainModules.Contains(pkg.mod.Path) {
 			continue
 		}
 
@@ -1587,7 +1587,7 @@ func (ld *loader) resolveMissingImports(ctx context.Context) (modAddedBy map[mod
 				var ime *ImportMissingError
 				if errors.As(err, &ime) {
 					for curstack := pkg.stack; curstack != nil; curstack = curstack.stack {
-						if MainModules.Contains(curstack.mod.Path) {
+						if LoaderState.MainModules.Contains(curstack.mod.Path) {
 							ime.ImportingMainModule = curstack.mod
 							break
 						}
@@ -1709,7 +1709,7 @@ func (ld *loader) applyPkgFlags(ctx context.Context, pkg *loadPkg, flags loadPkg
 		// so it's ok if we call it more than is strictly necessary.
 		wantTest := false
 		switch {
-		case ld.allPatternIsRoot && MainModules.Contains(pkg.mod.Path):
+		case ld.allPatternIsRoot && LoaderState.MainModules.Contains(pkg.mod.Path):
 			// We are loading the "all" pattern, which includes packages imported by
 			// tests in the main module. This package is in the main module, so we
 			// need to identify the imports of its test even if LoadTests is not set.
@@ -1730,7 +1730,7 @@ func (ld *loader) applyPkgFlags(ctx context.Context, pkg *loadPkg, flags loadPkg
 
 		if wantTest {
 			var testFlags loadPkgFlags
-			if MainModules.Contains(pkg.mod.Path) || (ld.allClosesOverTests && new.has(pkgInAll)) {
+			if LoaderState.MainModules.Contains(pkg.mod.Path) || (ld.allClosesOverTests && new.has(pkgInAll)) {
 				// Tests of packages in the main module are in "all", in the sense that
 				// they cause the packages they import to also be in "all". So are tests
 				// of packages in "all" if "all" closes over test dependencies.
@@ -1858,7 +1858,7 @@ func (ld *loader) load(ctx context.Context, pkg *loadPkg) {
 
 	var modroot string
 	pkg.mod, modroot, pkg.dir, pkg.altMods, pkg.err = importFromModules(ctx, pkg.path, ld.requirements, mg, ld.skipImportModFiles)
-	if MainModules.Tools()[pkg.path] {
+	if LoaderState.MainModules.Tools()[pkg.path] {
 		// Tools declared by main modules are always in "all".
 		// We apply the package flags before returning so that missing
 		// tool dependencies report an error https://go.dev/issue/70582
@@ -1867,7 +1867,7 @@ func (ld *loader) load(ctx context.Context, pkg *loadPkg) {
 	if pkg.dir == "" {
 		return
 	}
-	if MainModules.Contains(pkg.mod.Path) {
+	if LoaderState.MainModules.Contains(pkg.mod.Path) {
 		// Go ahead and mark pkg as in "all". This provides the invariant that a
 		// package that is *only* imported by other packages in "all" is always
 		// marked as such before loading its imports.
@@ -1975,14 +1975,14 @@ func (ld *loader) stdVendor(parentPath, path string) string {
 	}
 
 	if str.HasPathPrefix(parentPath, "cmd") {
-		if !ld.VendorModulesInGOROOTSrc || !MainModules.Contains("cmd") {
+		if !ld.VendorModulesInGOROOTSrc || !LoaderState.MainModules.Contains("cmd") {
 			vendorPath := pathpkg.Join("cmd", "vendor", path)
 
 			if _, err := os.Stat(filepath.Join(cfg.GOROOTsrc, filepath.FromSlash(vendorPath))); err == nil {
 				return vendorPath
 			}
 		}
-	} else if !ld.VendorModulesInGOROOTSrc || !MainModules.Contains("std") || str.HasPathPrefix(parentPath, "vendor") {
+	} else if !ld.VendorModulesInGOROOTSrc || !LoaderState.MainModules.Contains("std") || str.HasPathPrefix(parentPath, "vendor") {
 		// If we are outside of the 'std' module, resolve imports from within 'std'
 		// to the vendor directory.
 		//
@@ -2067,7 +2067,7 @@ func (ld *loader) checkTidyCompatibility(ctx context.Context, rs *Requirements,
 		fmt.Fprintln(os.Stderr)
 
 		goFlag := ""
-		if goVersion != MainModules.GoVersion() {
+		if goVersion != LoaderState.MainModules.GoVersion() {
 			goFlag = " -go=" + goVersion
 		}
 
diff --git a/src/cmd/go/internal/modload/modfile.go b/src/cmd/go/internal/modload/modfile.go
index 04e204cc984c59..6b432ed9637ec5 100644
--- a/src/cmd/go/internal/modload/modfile.go
+++ b/src/cmd/go/internal/modload/modfile.go
@@ -156,8 +156,8 @@ var ErrDisallowed = errors.New("disallowed module version")
 // CheckExclusions returns an error equivalent to ErrDisallowed if module m is
 // excluded by the main module's go.mod file.
 func CheckExclusions(ctx context.Context, m module.Version) error {
-	for _, mainModule := range MainModules.Versions() {
-		if index := MainModules.Index(mainModule); index != nil && index.exclude[m] {
+	for _, mainModule := range LoaderState.MainModules.Versions() {
+		if index := LoaderState.MainModules.Index(mainModule); index != nil && index.exclude[m] {
 			return module.VersionError(m, errExcluded)
 		}
 	}
@@ -349,19 +349,19 @@ func Replacement(mod module.Version) module.Version {
 // and the source of the replacement. The replacement is relative to the go.work or go.mod file it appears in.
 func replacementFrom(mod module.Version) (r module.Version, modroot string, fromFile string) {
 	foundFrom, found, foundModRoot := "", module.Version{}, ""
-	if MainModules == nil {
+	if LoaderState.MainModules == nil {
 		return module.Version{}, "", ""
-	} else if MainModules.Contains(mod.Path) && mod.Version == "" {
+	} else if LoaderState.MainModules.Contains(mod.Path) && mod.Version == "" {
 		// Don't replace the workspace version of the main module.
 		return module.Version{}, "", ""
 	}
-	if _, r, ok := replacement(mod, MainModules.WorkFileReplaceMap()); ok {
+	if _, r, ok := replacement(mod, LoaderState.MainModules.WorkFileReplaceMap()); ok {
 		return r, "", workFilePath
 	}
-	for _, v := range MainModules.Versions() {
-		if index := MainModules.Index(v); index != nil {
+	for _, v := range LoaderState.MainModules.Versions() {
+		if index := LoaderState.MainModules.Index(v); index != nil {
 			if from, r, ok := replacement(mod, index.replace); ok {
-				modRoot := MainModules.ModRoot(v)
+				modRoot := LoaderState.MainModules.ModRoot(v)
 				if foundModRoot != "" && foundFrom != from && found != r {
 					base.Errorf("conflicting replacements found for %v in workspace modules defined by %v and %v",
 						mod, modFilePath(foundModRoot), modFilePath(modRoot))
@@ -378,7 +378,7 @@ func replaceRelativeTo() string {
 	if workFilePath := WorkFilePath(); workFilePath != "" {
 		return filepath.Dir(workFilePath)
 	}
-	return MainModules.ModRoot(MainModules.mustGetSingleMainModule())
+	return LoaderState.MainModules.ModRoot(LoaderState.MainModules.mustGetSingleMainModule())
 }
 
 // canonicalizeReplacePath ensures that relative, on-disk, replaced module paths
@@ -572,7 +572,7 @@ type retraction struct {
 //
 // The caller must not modify the returned summary.
 func goModSummary(m module.Version) (*modFileSummary, error) {
-	if m.Version == "" && !inWorkspaceMode() && MainModules.Contains(m.Path) {
+	if m.Version == "" && !inWorkspaceMode() && LoaderState.MainModules.Contains(m.Path) {
 		panic("internal error: goModSummary called on a main module")
 	}
 	if gover.IsToolchain(m.Path) {
@@ -639,8 +639,8 @@ func goModSummary(m module.Version) (*modFileSummary, error) {
 		}
 	}
 
-	for _, mainModule := range MainModules.Versions() {
-		if index := MainModules.Index(mainModule); index != nil && len(index.exclude) > 0 {
+	for _, mainModule := range LoaderState.MainModules.Versions() {
+		if index := LoaderState.MainModules.Index(mainModule); index != nil && len(index.exclude) > 0 {
 			// Drop any requirements on excluded versions.
 			// Don't modify the cached summary though, since we might need the raw
 			// summary separately.
@@ -684,7 +684,7 @@ func rawGoModSummary(m module.Version) (*modFileSummary, error) {
 		}
 		return &modFileSummary{module: m}, nil
 	}
-	if m.Version == "" && !inWorkspaceMode() && MainModules.Contains(m.Path) {
+	if m.Version == "" && !inWorkspaceMode() && LoaderState.MainModules.Contains(m.Path) {
 		// Calling rawGoModSummary implies that we are treating m as a module whose
 		// requirements aren't the roots of the module graph and can't be modified.
 		//
@@ -697,13 +697,13 @@ func rawGoModSummary(m module.Version) (*modFileSummary, error) {
 		// If there are no modules in the workspace, we synthesize an empty
 		// command-line-arguments module, which rawGoModData cannot read a go.mod for.
 		return &modFileSummary{module: m}, nil
-	} else if m.Version == "" && inWorkspaceMode() && MainModules.Contains(m.Path) {
+	} else if m.Version == "" && inWorkspaceMode() && LoaderState.MainModules.Contains(m.Path) {
 		// When go get uses EnterWorkspace to check that the workspace loads properly,
 		// it will update the contents of the workspace module's modfile in memory. To use the updated
 		// contents of the modfile when doing the load, don't read from disk and instead
 		// recompute a summary using the updated contents of the modfile.
-		if mf := MainModules.ModFile(m); mf != nil {
-			return summaryFromModFile(m, MainModules.modFiles[m])
+		if mf := LoaderState.MainModules.ModFile(m); mf != nil {
+			return summaryFromModFile(m, LoaderState.MainModules.modFiles[m])
 		}
 	}
 	return rawGoModSummaryCache.Do(m, func() (*modFileSummary, error) {
@@ -783,8 +783,8 @@ func rawGoModData(m module.Version) (name string, data []byte, err error) {
 	if m.Version == "" {
 		dir := m.Path
 		if !filepath.IsAbs(dir) {
-			if inWorkspaceMode() && MainModules.Contains(m.Path) {
-				dir = MainModules.ModRoot(m)
+			if inWorkspaceMode() && LoaderState.MainModules.Contains(m.Path) {
+				dir = LoaderState.MainModules.ModRoot(m)
 			} else {
 				// m is a replacement module with only a file path.
 				dir = filepath.Join(replaceRelativeTo(), dir)
diff --git a/src/cmd/go/internal/modload/mvs.go b/src/cmd/go/internal/modload/mvs.go
index 8ae2dbff1e8887..97e6fe44dd7545 100644
--- a/src/cmd/go/internal/modload/mvs.go
+++ b/src/cmd/go/internal/modload/mvs.go
@@ -43,7 +43,7 @@ type mvsReqs struct {
 }
 
 func (r *mvsReqs) Required(mod module.Version) ([]module.Version, error) {
-	if mod.Version == "" && MainModules.Contains(mod.Path) {
+	if mod.Version == "" && LoaderState.MainModules.Contains(mod.Path) {
 		// Use the build list as it existed when r was constructed, not the current
 		// global build list.
 		return r.roots, nil
@@ -112,7 +112,7 @@ func versions(ctx context.Context, path string, allowed AllowedFunc) (versions [
 // Since the version of a main module is not found in the version list,
 // it has no previous version.
 func previousVersion(ctx context.Context, m module.Version) (module.Version, error) {
-	if m.Version == "" && MainModules.Contains(m.Path) {
+	if m.Version == "" && LoaderState.MainModules.Contains(m.Path) {
 		return module.Version{Path: m.Path, Version: "none"}, nil
 	}
 
diff --git a/src/cmd/go/internal/modload/query.go b/src/cmd/go/internal/modload/query.go
index 65934b0d69e517..94ee8bc955918c 100644
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@@ -211,7 +211,7 @@ func queryProxy(ctx context.Context, proxy, path, query, current string, allowed
 		allowed = func(context.Context, module.Version) error { return nil }
 	}
 
-	if MainModules.Contains(path) && (query == "upgrade" || query == "patch") {
+	if LoaderState.MainModules.Contains(path) && (query == "upgrade" || query == "patch") {
 		m := module.Version{Path: path}
 		if err := allowed(ctx, m); err != nil {
 			return nil, fmt.Errorf("internal error: main module version is not allowed: %w", err)
@@ -700,8 +700,8 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 		match = func(mod module.Version, roots []string, isLocal bool) *search.Match {
 			m := search.NewMatch(pattern)
 			prefix := mod.Path
-			if MainModules.Contains(mod.Path) {
-				prefix = MainModules.PathPrefix(module.Version{Path: mod.Path})
+			if LoaderState.MainModules.Contains(mod.Path) {
+				prefix = LoaderState.MainModules.PathPrefix(module.Version{Path: mod.Path})
 			}
 			for _, root := range roots {
 				if _, ok, err := dirInModule(pattern, prefix, root, isLocal); err != nil {
@@ -715,7 +715,7 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 	}
 
 	var mainModuleMatches []module.Version
-	for _, mainModule := range MainModules.Versions() {
+	for _, mainModule := range LoaderState.MainModules.Versions() {
 		m := match(mainModule, LoaderState.modRoots, true)
 		if len(m.Pkgs) > 0 {
 			if query != "upgrade" && query != "patch" {
@@ -842,7 +842,7 @@ func modulePrefixesExcludingTarget(path string) []string {
 	prefixes := make([]string, 0, strings.Count(path, "/")+1)
 
 	mainModulePrefixes := make(map[string]bool)
-	for _, m := range MainModules.Versions() {
+	for _, m := range LoaderState.MainModules.Versions() {
 		mainModulePrefixes[m.Path] = true
 	}
 
@@ -905,7 +905,7 @@ func queryPrefixModules(ctx context.Context, candidateModules []string, queryMod
 		case *PackageNotInModuleError:
 			// Given the option, prefer to attribute “package not in module”
 			// to modules other than the main one.
-			if noPackage == nil || MainModules.Contains(noPackage.Mod.Path) {
+			if noPackage == nil || LoaderState.MainModules.Contains(noPackage.Mod.Path) {
 				noPackage = rErr
 			}
 		case *NoMatchingVersionError:
@@ -1127,9 +1127,9 @@ func lookupRepo(ctx context.Context, proxy, path string) (repo versionRepo, err
 		repo = emptyRepo{path: path, err: err}
 	}
 
-	if MainModules == nil {
+	if LoaderState.MainModules == nil {
 		return repo, err
-	} else if _, ok := MainModules.HighestReplaced()[path]; ok {
+	} else if _, ok := LoaderState.MainModules.HighestReplaced()[path]; ok {
 		return &replacementRepo{repo: repo}, nil
 	}
 
@@ -1186,8 +1186,8 @@ func (rr *replacementRepo) Versions(ctx context.Context, prefix string) (*modfet
 	}
 
 	versions := repoVersions.List
-	for _, mm := range MainModules.Versions() {
-		if index := MainModules.Index(mm); index != nil && len(index.replace) > 0 {
+	for _, mm := range LoaderState.MainModules.Versions() {
+		if index := LoaderState.MainModules.Index(mm); index != nil && len(index.replace) > 0 {
 			path := rr.ModulePath()
 			for m := range index.replace {
 				if m.Path == path && strings.HasPrefix(m.Version, prefix) && m.Version != "" && !module.IsPseudoVersion(m.Version) {
@@ -1215,8 +1215,8 @@ func (rr *replacementRepo) Stat(ctx context.Context, rev string) (*modfetch.RevI
 		return info, err
 	}
 	var hasReplacements bool
-	for _, v := range MainModules.Versions() {
-		if index := MainModules.Index(v); index != nil && len(index.replace) > 0 {
+	for _, v := range LoaderState.MainModules.Versions() {
+		if index := LoaderState.MainModules.Index(v); index != nil && len(index.replace) > 0 {
 			hasReplacements = true
 		}
 	}
@@ -1249,7 +1249,7 @@ func (rr *replacementRepo) Latest(ctx context.Context) (*modfetch.RevInfo, error
 	info, err := rr.repo.Latest(ctx)
 	path := rr.ModulePath()
 
-	if v, ok := MainModules.HighestReplaced()[path]; ok {
+	if v, ok := LoaderState.MainModules.HighestReplaced()[path]; ok {
 		if v == "" {
 			// The only replacement is a wildcard that doesn't specify a version, so
 			// synthesize a pseudo-version with an appropriate major version and a
@@ -1290,7 +1290,7 @@ type QueryMatchesMainModulesError struct {
 }
 
 func (e *QueryMatchesMainModulesError) Error() string {
-	if MainModules.Contains(e.Pattern) {
+	if LoaderState.MainModules.Contains(e.Pattern) {
 		return fmt.Sprintf("can't request version %q of the main module (%s)", e.Query, e.Pattern)
 	}
 
diff --git a/src/cmd/go/internal/modload/search.go b/src/cmd/go/internal/modload/search.go
index 9ff9738e281118..205db3e8f7c8db 100644
--- a/src/cmd/go/internal/modload/search.go
+++ b/src/cmd/go/internal/modload/search.go
@@ -171,9 +171,9 @@ func matchPackages(ctx context.Context, m *search.Match, tags map[string]bool, f
 	}
 
 	if cfg.BuildMod == "vendor" {
-		for _, mod := range MainModules.Versions() {
-			if modRoot := MainModules.ModRoot(mod); modRoot != "" {
-				walkPkgs(modRoot, MainModules.PathPrefix(mod), pruneGoMod|pruneVendor)
+		for _, mod := range LoaderState.MainModules.Versions() {
+			if modRoot := LoaderState.MainModules.ModRoot(mod); modRoot != "" {
+				walkPkgs(modRoot, LoaderState.MainModules.PathPrefix(mod), pruneGoMod|pruneVendor)
 			}
 		}
 		if HasModRoot() {
@@ -191,12 +191,12 @@ func matchPackages(ctx context.Context, m *search.Match, tags map[string]bool, f
 			root, modPrefix string
 			isLocal         bool
 		)
-		if MainModules.Contains(mod.Path) {
-			if MainModules.ModRoot(mod) == "" {
+		if LoaderState.MainModules.Contains(mod.Path) {
+			if LoaderState.MainModules.ModRoot(mod) == "" {
 				continue // If there is no main module, we can't search in it.
 			}
-			root = MainModules.ModRoot(mod)
-			modPrefix = MainModules.PathPrefix(mod)
+			root = LoaderState.MainModules.ModRoot(mod)
+			modPrefix = LoaderState.MainModules.PathPrefix(mod)
 			isLocal = true
 		} else {
 			var err error
@@ -330,12 +330,12 @@ func parseIgnorePatterns(ctx context.Context, treeCanMatch func(string) bool, mo
 		}
 		var modRoot string
 		var ignorePatterns []string
-		if MainModules.Contains(mod.Path) {
-			modRoot = MainModules.ModRoot(mod)
+		if LoaderState.MainModules.Contains(mod.Path) {
+			modRoot = LoaderState.MainModules.ModRoot(mod)
 			if modRoot == "" {
 				continue
 			}
-			modIndex := MainModules.Index(mod)
+			modIndex := LoaderState.MainModules.Index(mod)
 			if modIndex == nil {
 				continue
 			}
diff --git a/src/cmd/go/internal/modload/vendor.go b/src/cmd/go/internal/modload/vendor.go
index c7fe73193582ab..d3f055acf64f50 100644
--- a/src/cmd/go/internal/modload/vendor.go
+++ b/src/cmd/go/internal/modload/vendor.go
@@ -236,8 +236,8 @@ func checkVendorConsistency(indexes []*modFileIndex, modFiles []*modfile.File, m
 	for _, modFile := range modFiles {
 		checkReplace(modFile.Replace)
 	}
-	if MainModules.workFile != nil {
-		checkReplace(MainModules.workFile.Replace)
+	if LoaderState.MainModules.workFile != nil {
+		checkReplace(LoaderState.MainModules.workFile.Replace)
 	}
 
 	for _, mod := range vendorList {
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 8bfb3c149b6c69..7a2963ff29b06e 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -730,7 +730,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 		// the module cache (or permanently alter the behavior of std tests for all
 		// users) by writing the failing input to the package's testdata directory.
 		// (See https://golang.org/issue/48495 and test_fuzz_modcache.txt.)
-		mainMods := modload.MainModules
+		mainMods := modload.LoaderState.MainModules
 		if m := pkgs[0].Module; m != nil && m.Path != "" {
 			if !mainMods.Contains(m.Path) {
 				base.Fatalf("cannot use -fuzz flag on package outside the main module")
diff --git a/src/cmd/go/internal/tool/tool.go b/src/cmd/go/internal/tool/tool.go
index ef25d17b54d892..e25c06a8f046bd 100644
--- a/src/cmd/go/internal/tool/tool.go
+++ b/src/cmd/go/internal/tool/tool.go
@@ -163,7 +163,7 @@ func listTools(ctx context.Context) {
 
 	modload.InitWorkfile()
 	modload.LoadModFile(ctx)
-	modTools := slices.Sorted(maps.Keys(modload.MainModules.Tools()))
+	modTools := slices.Sorted(maps.Keys(modload.LoaderState.MainModules.Tools()))
 	for _, tool := range modTools {
 		fmt.Println(tool)
 	}
@@ -256,7 +256,7 @@ func loadModTool(ctx context.Context, name string) string {
 	modload.LoadModFile(ctx)
 
 	matches := []string{}
-	for tool := range modload.MainModules.Tools() {
+	for tool := range modload.LoaderState.MainModules.Tools() {
 		if tool == name || defaultExecName(tool) == name {
 			matches = append(matches, tool)
 		}
diff --git a/src/cmd/go/internal/workcmd/sync.go b/src/cmd/go/internal/workcmd/sync.go
index 800dd15dd6f6d1..640771d8f75996 100644
--- a/src/cmd/go/internal/workcmd/sync.go
+++ b/src/cmd/go/internal/workcmd/sync.go
@@ -60,7 +60,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 	}
 	mustSelectFor := map[module.Version][]module.Version{}
 
-	mms := modload.MainModules
+	mms := modload.LoaderState.MainModules
 
 	opts := modload.PackageOpts{
 		Tags:                     imports.AnyTags(),
@@ -131,7 +131,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 			}, "all")
 			modload.WriteGoMod(ctx, modload.WriteOpts{})
 		}
-		goV = gover.Max(goV, modload.MainModules.GoVersion())
+		goV = gover.Max(goV, modload.LoaderState.MainModules.GoVersion())
 	}
 
 	wf, err := modload.ReadWorkFile(workFilePath)

From cb81270113968408d7cc41c0b1530adb51dd8496 Mon Sep 17 00:00:00 2001
From: Keith Randall 
Date: Tue, 7 Oct 2025 10:12:43 -0700
Subject: [PATCH 091/229] Revert "crypto/internal/fips140/subtle: add assembly
 implementation of xorBytes for mipsx"

This reverts commit 343e486bfdbf9ca614d3e197afd79ad7ed5fef3e.

Reason for revert: doesn't handle unaligned accesses correctly.

Update #74998

Change-Id: I1d6210eeca9336f2ce311e99944cb270565563aa
Reviewed-on: https://go-review.googlesource.com/c/go/+/709795
Reviewed-by: Cherry Mui 
Reviewed-by: Michael Knyszek 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
---
 src/crypto/internal/fips140/subtle/xor_asm.go |   2 +-
 .../internal/fips140/subtle/xor_generic.go    |   2 +-
 .../internal/fips140/subtle/xor_mipsx.s       | 212 ------------------
 3 files changed, 2 insertions(+), 214 deletions(-)
 delete mode 100644 src/crypto/internal/fips140/subtle/xor_mipsx.s

diff --git a/src/crypto/internal/fips140/subtle/xor_asm.go b/src/crypto/internal/fips140/subtle/xor_asm.go
index b07239da3e31c1..e10ea8b441429b 100644
--- a/src/crypto/internal/fips140/subtle/xor_asm.go
+++ b/src/crypto/internal/fips140/subtle/xor_asm.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (amd64 || arm64 || mips || mipsle || mips64 || mips64le || ppc64 || ppc64le || riscv64) && !purego
+//go:build (amd64 || arm64 || mips64 || mips64le || ppc64 || ppc64le || riscv64) && !purego
 
 package subtle
 
diff --git a/src/crypto/internal/fips140/subtle/xor_generic.go b/src/crypto/internal/fips140/subtle/xor_generic.go
index ed484bc630e98d..08af84de2a3dab 100644
--- a/src/crypto/internal/fips140/subtle/xor_generic.go
+++ b/src/crypto/internal/fips140/subtle/xor_generic.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (!amd64 && !arm64 && !loong64 && !mips && !mipsle && !mips64 && !mips64le && !ppc64 && !ppc64le && !riscv64) || purego
+//go:build (!amd64 && !arm64 && !loong64 && !mips64 && !mips64le && !ppc64 && !ppc64le && !riscv64) || purego
 
 package subtle
 
diff --git a/src/crypto/internal/fips140/subtle/xor_mipsx.s b/src/crypto/internal/fips140/subtle/xor_mipsx.s
deleted file mode 100644
index 1a6b3f409dddc9..00000000000000
--- a/src/crypto/internal/fips140/subtle/xor_mipsx.s
+++ /dev/null
@@ -1,212 +0,0 @@
-// Copyright 2025 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build (mips || mipsle) && !purego
-
-#include "textflag.h"
-
-// func xorBytes(dst, a, b *byte, n int)
-TEXT ·xorBytes(SB), NOSPLIT|NOFRAME, $0
-	MOVW	dst+0(FP), R1
-	MOVW	a+4(FP), R2
-	MOVW	b+8(FP), R3
-	MOVW	n+12(FP), R4
-
-	SGTU	$64, R4, R5 // R5 = 1 if (64 > R4)
-	BNE	R5, xor_32_check
-xor_64:
-	MOVW	(R2), R6
-	MOVW	4(R2), R7
-	MOVW	8(R2), R8
-	MOVW	12(R2), R9
-	MOVW	(R3), R10
-	MOVW	4(R3), R11
-	MOVW	8(R3), R12
-	MOVW	12(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVW	R10, (R1)
-	MOVW	R11, 4(R1)
-	MOVW	R12, 8(R1)
-	MOVW	R13, 12(R1)
-	MOVW	16(R2), R6
-	MOVW	20(R2), R7
-	MOVW	24(R2), R8
-	MOVW	28(R2), R9
-	MOVW	16(R3), R10
-	MOVW	20(R3), R11
-	MOVW	24(R3), R12
-	MOVW	28(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVW	R10, 16(R1)
-	MOVW	R11, 20(R1)
-	MOVW	R12, 24(R1)
-	MOVW	R13, 28(R1)
-	MOVW	32(R2), R6
-	MOVW	36(R2), R7
-	MOVW	40(R2), R8
-	MOVW	44(R2), R9
-	MOVW	32(R3), R10
-	MOVW	36(R3), R11
-	MOVW	40(R3), R12
-	MOVW	44(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVW	R10, 32(R1)
-	MOVW	R11, 36(R1)
-	MOVW	R12, 40(R1)
-	MOVW	R13, 44(R1)
-	MOVW	48(R2), R6
-	MOVW	52(R2), R7
-	MOVW	56(R2), R8
-	MOVW	60(R2), R9
-	MOVW	48(R3), R10
-	MOVW	52(R3), R11
-	MOVW	56(R3), R12
-	MOVW	60(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVW	R10, 48(R1)
-	MOVW	R11, 52(R1)
-	MOVW	R12, 56(R1)
-	MOVW	R13, 60(R1)
-	ADD	$64, R2
-	ADD	$64, R3
-	ADD	$64, R1
-	SUB	$64, R4
-	SGTU	$64, R4, R5
-	BEQ	R0, R5, xor_64
-	BEQ	R0, R4, end
-
-xor_32_check:
-	SGTU	$32, R4, R5
-	BNE	R5, xor_16_check
-xor_32:
-	MOVW	(R2), R6
-	MOVW	4(R2), R7
-	MOVW	8(R2), R8
-	MOVW	12(R2), R9
-	MOVW	(R3), R10
-	MOVW	4(R3), R11
-	MOVW	8(R3), R12
-	MOVW	12(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVW	R10, (R1)
-	MOVW	R11, 4(R1)
-	MOVW	R12, 8(R1)
-	MOVW	R13, 12(R1)
-	MOVW	16(R2), R6
-	MOVW	20(R2), R7
-	MOVW	24(R2), R8
-	MOVW	28(R2), R9
-	MOVW	16(R3), R10
-	MOVW	20(R3), R11
-	MOVW	24(R3), R12
-	MOVW	28(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVW	R10, 16(R1)
-	MOVW	R11, 20(R1)
-	MOVW	R12, 24(R1)
-	MOVW	R13, 28(R1)
-	ADD	$32, R2
-	ADD	$32, R3
-	ADD	$32, R1
-	SUB	$32, R4
-	BEQ	R0, R4, end
-
-xor_16_check:
-	SGTU	$16, R4, R5
-	BNE	R5, xor_8_check
-xor_16:
-	MOVW	(R2), R6
-	MOVW	4(R2), R7
-	MOVW	8(R2), R8
-	MOVW	12(R2), R9
-	MOVW	(R3), R10
-	MOVW	4(R3), R11
-	MOVW	8(R3), R12
-	MOVW	12(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVW	R10, (R1)
-	MOVW	R11, 4(R1)
-	MOVW	R12, 8(R1)
-	MOVW	R13, 12(R1)
-	ADD	$16, R2
-	ADD	$16, R3
-	ADD	$16, R1
-	SUB	$16, R4
-	BEQ	R0, R4, end
-
-xor_8_check:
-	SGTU	$8, R4, R5
-	BNE	R5, xor_4_check
-xor_8:
-	MOVW	(R2), R6
-	MOVW	4(R2), R7
-	MOVW	(R3), R8
-	MOVW	4(R3), R9
-	XOR	R6, R8
-	XOR	R7, R9
-	MOVW	R8, (R1)
-	MOVW	R9, 4(R1)
-	ADD	$8, R1
-	ADD	$8, R2
-	ADD	$8, R3
-	SUB	$8, R4
-	BEQ	R0, R4, end
-
-xor_4_check:
-	SGTU	$4, R4, R5
-	BNE	R5, xor_2_check
-xor_4:
-	MOVW	(R2), R6
-	MOVW	(R3), R7
-	XOR	R6, R7
-	MOVW	R7, (R1)
-	ADD	$4, R2
-	ADD	$4, R3
-	ADD	$4, R1
-	SUB	$4, R4
-	BEQ	R0, R4, end
-
-xor_2_check:
-	SGTU	$2, R4, R5
-	BNE	R5, xor_1
-xor_2:
-	MOVH	(R2), R6
-	MOVH	(R3), R7
-	XOR	R6, R7
-	MOVH	R7, (R1)
-	ADD	$2, R2
-	ADD	$2, R3
-	ADD	$2, R1
-	SUB	$2, R4
-	BEQ	R0, R4, end
-
-xor_1:
-	MOVB	(R2), R6
-	MOVB	(R3), R7
-	XOR	R6, R7
-	MOVB	R7, (R1)
-
-end:
-	RET

From a1661e776f57602b4d4470389a0246f9784fd722 Mon Sep 17 00:00:00 2001
From: Keith Randall 
Date: Tue, 7 Oct 2025 10:15:43 -0700
Subject: [PATCH 092/229] Revert "crypto/internal/fips140/subtle: add assembly
 implementation of xorBytes for mips64x"

This reverts commit 49d6777d87a0abb3eda032da95eff024156835f7.

Reason for revert: doesn't handle unaligned accesses correctly

Fixes #74998

Change-Id: Ia272245a6a2a91b305d411207430bad660ee355b
Reviewed-on: https://go-review.googlesource.com/c/go/+/709757
Reviewed-by: Keith Randall 
Reviewed-by: Cherry Mui 
LUCI-TryBot-Result: Go LUCI 
---
 src/crypto/internal/fips140/subtle/xor_asm.go |   2 +-
 .../internal/fips140/subtle/xor_generic.go    |   2 +-
 .../internal/fips140/subtle/xor_mips64x.s     | 153 ------------------
 3 files changed, 2 insertions(+), 155 deletions(-)
 delete mode 100644 src/crypto/internal/fips140/subtle/xor_mips64x.s

diff --git a/src/crypto/internal/fips140/subtle/xor_asm.go b/src/crypto/internal/fips140/subtle/xor_asm.go
index e10ea8b441429b..bb85aefef4013e 100644
--- a/src/crypto/internal/fips140/subtle/xor_asm.go
+++ b/src/crypto/internal/fips140/subtle/xor_asm.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (amd64 || arm64 || mips64 || mips64le || ppc64 || ppc64le || riscv64) && !purego
+//go:build (amd64 || arm64 || ppc64 || ppc64le || riscv64) && !purego
 
 package subtle
 
diff --git a/src/crypto/internal/fips140/subtle/xor_generic.go b/src/crypto/internal/fips140/subtle/xor_generic.go
index 08af84de2a3dab..0b31eec60197d3 100644
--- a/src/crypto/internal/fips140/subtle/xor_generic.go
+++ b/src/crypto/internal/fips140/subtle/xor_generic.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (!amd64 && !arm64 && !loong64 && !mips64 && !mips64le && !ppc64 && !ppc64le && !riscv64) || purego
+//go:build (!amd64 && !arm64 && !loong64 && !ppc64 && !ppc64le && !riscv64) || purego
 
 package subtle
 
diff --git a/src/crypto/internal/fips140/subtle/xor_mips64x.s b/src/crypto/internal/fips140/subtle/xor_mips64x.s
deleted file mode 100644
index e580235914aeaf..00000000000000
--- a/src/crypto/internal/fips140/subtle/xor_mips64x.s
+++ /dev/null
@@ -1,153 +0,0 @@
-// Copyright 2025 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build (mips64 || mips64le) && !purego
-
-#include "textflag.h"
-
-// func xorBytes(dst, a, b *byte, n int)
-TEXT ·xorBytes(SB), NOSPLIT|NOFRAME, $0
-	MOVV	dst+0(FP), R1
-	MOVV	a+8(FP), R2
-	MOVV	b+16(FP), R3
-	MOVV	n+24(FP), R4
-
-xor_64_check:
-	SGTU	$64, R4, R5 // R5 = 1 if (64 > R4)
-	BNE	R5, xor_32_check
-xor_64:
-	MOVV	(R2), R6
-	MOVV	8(R2), R7
-	MOVV	16(R2), R8
-	MOVV	24(R2), R9
-	MOVV	(R3), R10
-	MOVV	8(R3), R11
-	MOVV	16(R3), R12
-	MOVV	24(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVV	R10, (R1)
-	MOVV	R11, 8(R1)
-	MOVV	R12, 16(R1)
-	MOVV	R13, 24(R1)
-	MOVV	32(R2), R6
-	MOVV	40(R2), R7
-	MOVV	48(R2), R8
-	MOVV	56(R2), R9
-	MOVV	32(R3), R10
-	MOVV	40(R3), R11
-	MOVV	48(R3), R12
-	MOVV	56(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVV	R10, 32(R1)
-	MOVV	R11, 40(R1)
-	MOVV	R12, 48(R1)
-	MOVV	R13, 56(R1)
-	ADDV	$64, R2
-	ADDV	$64, R3
-	ADDV	$64, R1
-	SUBV	$64, R4
-	SGTU	$64, R4, R5
-	BEQ	R0, R5, xor_64
-	BEQ	R0, R4, end
-
-xor_32_check:
-	SGTU	$32, R4, R5
-	BNE	R5, xor_16_check
-xor_32:
-	MOVV	(R2), R6
-	MOVV	8(R2), R7
-	MOVV	16(R2), R8
-	MOVV	24(R2), R9
-	MOVV	(R3), R10
-	MOVV	8(R3), R11
-	MOVV	16(R3), R12
-	MOVV	24(R3), R13
-	XOR	R6, R10
-	XOR	R7, R11
-	XOR	R8, R12
-	XOR	R9, R13
-	MOVV	R10, (R1)
-	MOVV	R11, 8(R1)
-	MOVV	R12, 16(R1)
-	MOVV	R13, 24(R1)
-	ADDV	$32, R2
-	ADDV	$32, R3
-	ADDV	$32, R1
-	SUBV	$32, R4
-	BEQ	R0, R4, end
-
-xor_16_check:
-	SGTU	$16, R4, R5
-	BNE	R5, xor_8_check
-xor_16:
-	MOVV	(R2), R6
-	MOVV	8(R2), R7
-	MOVV	(R3), R8
-	MOVV	8(R3), R9
-	XOR	R6, R8
-	XOR	R7, R9
-	MOVV	R8, (R1)
-	MOVV	R9, 8(R1)
-	ADDV	$16, R2
-	ADDV	$16, R3
-	ADDV	$16, R1
-	SUBV	$16, R4
-	BEQ	R0, R4, end
-
-xor_8_check:
-	SGTU	$8, R4, R5
-	BNE	R5, xor_4_check
-xor_8:
-	MOVV	(R2), R6
-	MOVV	(R3), R7
-	XOR	R6, R7
-	MOVV	R7, (R1)
-	ADDV	$8, R1
-	ADDV	$8, R2
-	ADDV	$8, R3
-	SUBV	$8, R4
-	BEQ	R0, R4, end
-
-xor_4_check:
-	SGTU	$4, R4, R5
-	BNE	R5, xor_2_check
-xor_4:
-	MOVW	(R2), R6
-	MOVW	(R3), R7
-	XOR	R6, R7
-	MOVW	R7, (R1)
-	ADDV	$4, R2
-	ADDV	$4, R3
-	ADDV	$4, R1
-	SUBV	$4, R4
-	BEQ	R0, R4, end
-
-xor_2_check:
-	SGTU	$2, R4, R5
-	BNE	R5, xor_1
-xor_2:
-	MOVH	(R2), R6
-	MOVH	(R3), R7
-	XOR	R6, R7
-	MOVH	R7, (R1)
-	ADDV	$2, R2
-	ADDV	$2, R3
-	ADDV	$2, R1
-	SUBV	$2, R4
-	BEQ	R0, R4, end
-
-xor_1:
-	MOVB	(R2), R6
-	MOVB	(R3), R7
-	XOR	R6, R7
-	MOVB	R7, (R1)
-
-end:
-	RET

From 162392773085d4cc12072200853a0424117983c0 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 20:14:59 -0400
Subject: [PATCH 093/229] cmd/go: refactor usage of `requirements`

This commit refactors usage of the global variable `requirements` to
the global LoaderState field of the same name.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf 'ex { requirements -> LoaderState.requirements }'
rf 'add State.MainModules \
// requirements is the requirement graph for the main module.\
//\
// It is always non-nil if the main module'\\\''s go.mod file has been\
// loaded.\
//\
// This variable should only be read from the loadModFile\
// function, and should only be written in the loadModFile and\
// commitRequirements functions.  All other functions that need or\
// produce a *Requirements should accept and/or return an explicit\
// parameter.'
rf 'rm requirements'

Change-Id: I9d7d1d301a9e89f9214ce632fa5b656dd2940f39
Reviewed-on: https://go-review.googlesource.com/c/go/+/698061
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modload/buildlist.go | 14 +-----
 src/cmd/go/internal/modload/init.go      | 55 ++++++++++++++----------
 src/cmd/go/internal/modload/list.go      |  2 +-
 src/cmd/go/internal/modload/load.go      |  8 ++--
 4 files changed, 40 insertions(+), 39 deletions(-)

diff --git a/src/cmd/go/internal/modload/buildlist.go b/src/cmd/go/internal/modload/buildlist.go
index 8afea0b205c4d7..b73cb43d0dc3cf 100644
--- a/src/cmd/go/internal/modload/buildlist.go
+++ b/src/cmd/go/internal/modload/buildlist.go
@@ -85,16 +85,6 @@ type cachedGraph struct {
 	err error // If err is non-nil, mg may be incomplete (but must still be non-nil).
 }
 
-// requirements is the requirement graph for the main module.
-//
-// It is always non-nil if the main module's go.mod file has been loaded.
-//
-// This variable should only be read from the loadModFile function, and should
-// only be written in the loadModFile and commitRequirements functions.
-// All other functions that need or produce a *Requirements should
-// accept and/or return an explicit parameter.
-var requirements *Requirements
-
 func mustHaveGoRoot(roots []module.Version) {
 	for _, m := range roots {
 		if m.Path == "go" {
@@ -589,7 +579,7 @@ func LoadModGraph(ctx context.Context, goVersion string) (*ModuleGraph, error) {
 	if err != nil {
 		return nil, err
 	}
-	requirements = rs
+	LoaderState.requirements = rs
 	return mg, nil
 }
 
@@ -654,7 +644,7 @@ func EditBuildList(ctx context.Context, add, mustSelect []module.Version) (chang
 	if err != nil {
 		return false, err
 	}
-	requirements = rs
+	LoaderState.requirements = rs
 	return changed, nil
 }
 
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 28f55a621d60de..1c8aa379d3cf78 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -59,7 +59,7 @@ var (
 // EnterModule resets MainModules and requirements to refer to just this one module.
 func EnterModule(ctx context.Context, enterModroot string) {
 	LoaderState.MainModules = nil // reset MainModules
-	requirements = nil
+	LoaderState.requirements = nil
 	workFilePath = "" // Force module mode
 	modfetch.Reset()
 
@@ -90,7 +90,7 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 
 	// Update the content of the previous main module, and recompute the requirements.
 	*LoaderState.MainModules.ModFile(mm) = *updatedmodfile
-	requirements = requirementsFromModFiles(ctx, LoaderState.MainModules.workFile, slices.Collect(maps.Values(LoaderState.MainModules.modFiles)), nil)
+	LoaderState.requirements = requirementsFromModFiles(ctx, LoaderState.MainModules.workFile, slices.Collect(maps.Values(LoaderState.MainModules.modFiles)), nil)
 
 	return func() {
 		setState(oldstate)
@@ -395,7 +395,7 @@ func setState(s State) State {
 		modRoots:        LoaderState.modRoots,
 		modulesEnabled:  cfg.ModulesEnabled,
 		MainModules:     LoaderState.MainModules,
-		requirements:    requirements,
+		requirements:    LoaderState.requirements,
 	}
 	LoaderState.initialized = s.initialized
 	LoaderState.ForceUseModules = s.ForceUseModules
@@ -403,7 +403,7 @@ func setState(s State) State {
 	LoaderState.modRoots = s.modRoots
 	cfg.ModulesEnabled = s.modulesEnabled
 	LoaderState.MainModules = s.MainModules
-	requirements = s.requirements
+	LoaderState.requirements = s.requirements
 	workFilePath = s.workFilePath
 	// The modfetch package's global state is used to compute
 	// the go.sum file, so save and restore it along with the
@@ -430,9 +430,20 @@ type State struct {
 	modRoots       []string
 	modulesEnabled bool
 	MainModules    *MainModuleSet
-	requirements   *Requirements
-	workFilePath   string
-	modfetchState  modfetch.State
+
+	// requirements is the requirement graph for the main module.
+	//
+	// It is always non-nil if the main module's go.mod file has been
+	// loaded.
+	//
+	// This variable should only be read from the loadModFile
+	// function, and should only be written in the loadModFile and
+	// commitRequirements functions.  All other functions that need or
+	// produce a *Requirements should accept and/or return an explicit
+	// parameter.
+	requirements  *Requirements
+	workFilePath  string
+	modfetchState modfetch.State
 }
 
 func NewState() *State { return &State{} }
@@ -869,8 +880,8 @@ func LoadModFile(ctx context.Context) *Requirements {
 }
 
 func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error) {
-	if requirements != nil {
-		return requirements, nil
+	if LoaderState.requirements != nil {
+		return LoaderState.requirements, nil
 	}
 
 	Init()
@@ -939,14 +950,14 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			}
 		}
 		rawGoVersion.Store(mainModule, goVersion)
-		requirements = newRequirements(pruning, roots, direct)
+		LoaderState.requirements = newRequirements(pruning, roots, direct)
 		if cfg.BuildMod == "vendor" {
 			// For issue 56536: Some users may have GOFLAGS=-mod=vendor set.
 			// Make sure it behaves as though the fake module is vendored
 			// with no dependencies.
-			requirements.initVendor(nil)
+			LoaderState.requirements.initVendor(nil)
 		}
-		return requirements, nil
+		return LoaderState.requirements, nil
 	}
 
 	var modFiles []*modfile.File
@@ -1035,7 +1046,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 
 	if inWorkspaceMode() {
 		// We don't need to update the mod file so return early.
-		requirements = rs
+		LoaderState.requirements = rs
 		return rs, nil
 	}
 
@@ -1081,8 +1092,8 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		}
 	}
 
-	requirements = rs
-	return requirements, nil
+	LoaderState.requirements = rs
+	return LoaderState.requirements, nil
 }
 
 func errWorkTooOld(gomod string, wf *modfile.WorkFile, goVers string) error {
@@ -1162,7 +1173,7 @@ func CreateModFile(ctx context.Context, modPath string) {
 	if err != nil {
 		base.Fatal(err)
 	}
-	requirements = rs
+	LoaderState.requirements = rs
 	if err := commitRequirements(ctx, WriteOpts{}); err != nil {
 		base.Fatal(err)
 	}
@@ -1801,7 +1812,7 @@ type WriteOpts struct {
 
 // WriteGoMod writes the current build list back to go.mod.
 func WriteGoMod(ctx context.Context, opts WriteOpts) error {
-	requirements = LoadModFile(ctx)
+	LoaderState.requirements = LoadModFile(ctx)
 	return commitRequirements(ctx, opts)
 }
 
@@ -1828,7 +1839,7 @@ func UpdateGoModFromReqs(ctx context.Context, opts WriteOpts) (before, after []b
 	var list []*modfile.Require
 	toolchain := ""
 	goVersion := ""
-	for _, m := range requirements.rootModules {
+	for _, m := range LoaderState.requirements.rootModules {
 		if m.Path == "go" {
 			goVersion = m.Version
 			continue
@@ -1839,7 +1850,7 @@ func UpdateGoModFromReqs(ctx context.Context, opts WriteOpts) (before, after []b
 		}
 		list = append(list, &modfile.Require{
 			Mod:      m,
-			Indirect: !requirements.direct[m.Path],
+			Indirect: !LoaderState.requirements.direct[m.Path],
 		})
 	}
 
@@ -1913,7 +1924,7 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 	if inWorkspaceMode() {
 		// go.mod files aren't updated in workspace mode, but we still want to
 		// update the go.work.sum file.
-		return modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, requirements, addBuildListZipSums), mustHaveCompleteRequirements())
+		return modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, LoaderState.requirements, addBuildListZipSums), mustHaveCompleteRequirements())
 	}
 	_, updatedGoMod, modFile, err := UpdateGoModFromReqs(ctx, opts)
 	if err != nil {
@@ -1937,7 +1948,7 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 		// Don't write go.mod, but write go.sum in case we added or trimmed sums.
 		// 'go mod init' shouldn't write go.sum, since it will be incomplete.
 		if cfg.CmdName != "mod init" {
-			if err := modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, requirements, addBuildListZipSums), mustHaveCompleteRequirements()); err != nil {
+			if err := modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, LoaderState.requirements, addBuildListZipSums), mustHaveCompleteRequirements()); err != nil {
 				return err
 			}
 		}
@@ -1960,7 +1971,7 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 		// 'go mod init' shouldn't write go.sum, since it will be incomplete.
 		if cfg.CmdName != "mod init" {
 			if err == nil {
-				err = modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, requirements, addBuildListZipSums), mustHaveCompleteRequirements())
+				err = modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, LoaderState.requirements, addBuildListZipSums), mustHaveCompleteRequirements())
 			}
 		}
 	}()
diff --git a/src/cmd/go/internal/modload/list.go b/src/cmd/go/internal/modload/list.go
index b2d071dcf69723..b66e73a112cedd 100644
--- a/src/cmd/go/internal/modload/list.go
+++ b/src/cmd/go/internal/modload/list.go
@@ -109,7 +109,7 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 	}
 
 	if err == nil {
-		requirements = rs
+		LoaderState.requirements = rs
 		// TODO(#61605): The extra ListU clause fixes a problem with Go 1.21rc3
 		// where "go mod tidy" and "go list -m -u all" fight over whether the go.sum
 		// should be considered up-to-date. The fix for now is to always treat the
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index 54e1da902cfd00..413de8148fb79e 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -455,7 +455,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 		if opts.TidyDiff {
 			cfg.BuildMod = "readonly"
 			loaded = ld
-			requirements = loaded.requirements
+			LoaderState.requirements = loaded.requirements
 			currentGoMod, updatedGoMod, _, err := UpdateGoModFromReqs(ctx, WriteOpts{})
 			if err != nil {
 				base.Fatal(err)
@@ -466,7 +466,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 			// Dropping compatibility for 1.16 may result in a strictly smaller go.sum.
 			// Update the keep map with only the loaded.requirements.
 			if gover.Compare(compatVersion, "1.16") > 0 {
-				keep = keepSums(ctx, loaded, requirements, addBuildListZipSums)
+				keep = keepSums(ctx, loaded, LoaderState.requirements, addBuildListZipSums)
 			}
 			currentGoSum, tidyGoSum := modfetch.TidyGoSum(keep)
 			goSumDiff := diff.Diff("current/go.sum", currentGoSum, "tidy/go.sum", tidyGoSum)
@@ -505,7 +505,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 	// to call WriteGoMod itself) or if ResolveMissingImports is false (the
 	// command wants to examine the package graph as-is).
 	loaded = ld
-	requirements = loaded.requirements
+	LoaderState.requirements = loaded.requirements
 
 	for _, pkg := range ld.pkgs {
 		if !pkg.isTest() {
@@ -788,7 +788,7 @@ func ImportFromFiles(ctx context.Context, gofiles []string) {
 			return roots
 		},
 	})
-	requirements = loaded.requirements
+	LoaderState.requirements = loaded.requirements
 
 	if !ExplicitWriteGoMod {
 		if err := commitRequirements(ctx, WriteOpts{}); err != nil {

From bb1ca7ae81ea8ca49a2773ace8ccff8fbc7f4dfd Mon Sep 17 00:00:00 2001
From: Damien Neil 
Date: Fri, 15 Aug 2025 15:24:05 -0700
Subject: [PATCH 094/229] cmd/go, testing: add TB.ArtifactDir and -artifacts
 flag

Add TB.ArtifactDir, which returns a directory for a test to store
output files in. Add a -artifacts testflag which enables persistent
storage of artifacts in the output directory (-outputdir, or the
current directory by default).

Fixes #71287

Change-Id: I5f6515a6cd6c103f88588f4c033d5ea11ffd0c3c
Reviewed-on: https://go-review.googlesource.com/c/go/+/696399
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Alan Donovan 
---
 api/next/71287.txt                          |   4 +
 doc/next/6-stdlib/99-minor/testing/71287.md |  18 ++
 src/cmd/go/alldocs.go                       |  12 +-
 src/cmd/go/internal/load/test.go            |   9 +
 src/cmd/go/internal/test/flagdefs.go        |   1 +
 src/cmd/go/internal/test/test.go            |  13 +-
 src/cmd/go/internal/test/testflag.go        |   4 +-
 src/cmd/internal/test2json/test2json.go     |  24 ++-
 src/testing/internal/testdeps/deps.go       |   6 +
 src/testing/testing.go                      | 207 +++++++++++++++-----
 src/testing/testing_test.go                 | 106 +++++++++-
 11 files changed, 333 insertions(+), 71 deletions(-)
 create mode 100644 api/next/71287.txt
 create mode 100644 doc/next/6-stdlib/99-minor/testing/71287.md

diff --git a/api/next/71287.txt b/api/next/71287.txt
new file mode 100644
index 00000000000000..c1e09a1f523082
--- /dev/null
+++ b/api/next/71287.txt
@@ -0,0 +1,4 @@
+pkg testing, method (*B) ArtifactDir() string #71287
+pkg testing, method (*F) ArtifactDir() string #71287
+pkg testing, method (*T) ArtifactDir() string #71287
+pkg testing, type TB interface, ArtifactDir() string #71287
diff --git a/doc/next/6-stdlib/99-minor/testing/71287.md b/doc/next/6-stdlib/99-minor/testing/71287.md
new file mode 100644
index 00000000000000..82cac638101099
--- /dev/null
+++ b/doc/next/6-stdlib/99-minor/testing/71287.md
@@ -0,0 +1,18 @@
+The new methods [T.ArtifactDir], [B.ArtifactDir], and [F.ArtifactDir]
+return a directory in which to write test output files (artifacts).
+
+When the `-artifacts` flag is provided to `go test`,
+this directory will be located under the output directory
+(specified with `-outputdir`, or the current directory by default).
+Otherwise, artifacts are stored in a temporary directory
+which is removed after the test completes.
+
+The first call to `ArtifactDir` when `-artifacts` is provided
+writes the location of the directory to the test log.
+
+For example, in a test named `TestArtifacts`,
+`t.ArtifactDir()` emits:
+
+```
+=== ARTIFACTS Test /path/to/artifact/dir
+```
diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 19b48f0579bb29..51f2223283b175 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -3244,6 +3244,10 @@
 // The following flags are recognized by the 'go test' command and
 // control the execution of any test:
 //
+//	-artifacts
+//	    Save test artifacts in the directory specified by -outputdir.
+//	    See 'go doc testing.T.ArtifactDir'.
+//
 //	-bench regexp
 //	    Run only those benchmarks matching a regular expression.
 //	    By default, no benchmarks are run.
@@ -3338,6 +3342,10 @@
 //	    This will only list top-level tests. No subtest or subbenchmarks will be
 //	    shown.
 //
+//	-outputdir directory
+//	    Place output files from profiling and test artifacts in the
+//	    specified directory, by default the directory in which "go test" is running.
+//
 //	-parallel n
 //	    Allow parallel execution of test functions that call t.Parallel, and
 //	    fuzz targets that call t.Parallel when running the seed corpus.
@@ -3449,10 +3457,6 @@
 //	    Sample 1 in n stack traces of goroutines holding a
 //	    contended mutex.
 //
-//	-outputdir directory
-//	    Place output files from profiling in the specified directory,
-//	    by default the directory in which "go test" is running.
-//
 //	-trace trace.out
 //	    Write an execution trace to the specified file before exiting.
 //
diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
index f895e3a2461d9e..9849ee138a5781 100644
--- a/src/cmd/go/internal/load/test.go
+++ b/src/cmd/go/internal/load/test.go
@@ -649,6 +649,14 @@ func (t *testFuncs) ImportPath() string {
 	return pkg
 }
 
+func (t *testFuncs) ModulePath() string {
+	m := t.Package.Module
+	if m == nil {
+		return ""
+	}
+	return m.Path
+}
+
 // Covered returns a string describing which packages are being tested for coverage.
 // If the covered package is the same as the tested package, it returns the empty string.
 // Otherwise it is a comma-separated human-readable list of packages beginning with
@@ -836,6 +844,7 @@ func init() {
 	testdeps.CoverMarkProfileEmittedFunc = cfile.MarkProfileEmitted
 
 {{end}}
+	testdeps.ModulePath = {{.ModulePath | printf "%q"}}
 	testdeps.ImportPath = {{.ImportPath | printf "%q"}}
 }
 
diff --git a/src/cmd/go/internal/test/flagdefs.go b/src/cmd/go/internal/test/flagdefs.go
index 8aa0bfc2bf3120..b8b4bf649e42e7 100644
--- a/src/cmd/go/internal/test/flagdefs.go
+++ b/src/cmd/go/internal/test/flagdefs.go
@@ -9,6 +9,7 @@ package test
 // passFlagToTest contains the flags that should be forwarded to
 // the test binary with the prefix "test.".
 var passFlagToTest = map[string]bool{
+	"artifacts":            true,
 	"bench":                true,
 	"benchmem":             true,
 	"benchtime":            true,
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 7a2963ff29b06e..15ffc618c65dab 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -192,6 +192,10 @@ and -show_bytes options of pprof control how the information is presented.
 The following flags are recognized by the 'go test' command and
 control the execution of any test:
 
+	-artifacts
+	    Save test artifacts in the directory specified by -outputdir.
+	    See 'go doc testing.T.ArtifactDir'.
+
 	-bench regexp
 	    Run only those benchmarks matching a regular expression.
 	    By default, no benchmarks are run.
@@ -286,6 +290,10 @@ control the execution of any test:
 	    This will only list top-level tests. No subtest or subbenchmarks will be
 	    shown.
 
+	-outputdir directory
+	    Place output files from profiling and test artifacts in the
+	    specified directory, by default the directory in which "go test" is running.
+
 	-parallel n
 	    Allow parallel execution of test functions that call t.Parallel, and
 	    fuzz targets that call t.Parallel when running the seed corpus.
@@ -397,10 +405,6 @@ profile the tests during execution:
 	    Sample 1 in n stack traces of goroutines holding a
 	    contended mutex.
 
-	-outputdir directory
-	    Place output files from profiling in the specified directory,
-	    by default the directory in which "go test" is running.
-
 	-trace trace.out
 	    Write an execution trace to the specified file before exiting.
 
@@ -540,6 +544,7 @@ See the documentation of the testing package for more information.
 }
 
 var (
+	testArtifacts    bool                              // -artifacts flag
 	testBench        string                            // -bench flag
 	testC            bool                              // -c flag
 	testCoverPkgs    []*load.Package                   // -coverpkg flag
diff --git a/src/cmd/go/internal/test/testflag.go b/src/cmd/go/internal/test/testflag.go
index 983e8f56e9af09..fc2b22cb56a9ee 100644
--- a/src/cmd/go/internal/test/testflag.go
+++ b/src/cmd/go/internal/test/testflag.go
@@ -44,6 +44,7 @@ func init() {
 	// some of them so that cmd/go knows what to do with the test output, or knows
 	// to build the test in a way that supports the use of the flag.
 
+	cf.BoolVar(&testArtifacts, "artifacts", false, "")
 	cf.StringVar(&testBench, "bench", "", "")
 	cf.Bool("benchmem", false, "")
 	cf.String("benchtime", "", "")
@@ -392,7 +393,8 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 	// directory, but 'go test' defaults it to the working directory of the 'go'
 	// command. Set it explicitly if it is needed due to some other flag that
 	// requests output.
-	if testProfile() != "" && !outputDirSet {
+	needOutputDir := testProfile() != "" || testArtifacts
+	if needOutputDir && !outputDirSet {
 		injectedFlags = append(injectedFlags, "-test.outputdir="+testOutputDir.getAbs())
 	}
 
diff --git a/src/cmd/internal/test2json/test2json.go b/src/cmd/internal/test2json/test2json.go
index d08ef389f82a21..f28051e1771db8 100644
--- a/src/cmd/internal/test2json/test2json.go
+++ b/src/cmd/internal/test2json/test2json.go
@@ -38,6 +38,7 @@ type event struct {
 	FailedBuild string     `json:",omitempty"`
 	Key         string     `json:",omitempty"`
 	Value       string     `json:",omitempty"`
+	Path        string     `json:",omitempty"`
 }
 
 // textBytes is a hack to get JSON to emit a []byte as a string
@@ -180,6 +181,7 @@ var (
 		[]byte("=== FAIL  "),
 		[]byte("=== SKIP  "),
 		[]byte("=== ATTR  "),
+		[]byte("=== ARTIFACTS "),
 	}
 
 	reports = [][]byte{
@@ -251,7 +253,6 @@ func (c *Converter) handleInputLine(line []byte) {
 	// "=== RUN   "
 	// "=== PAUSE "
 	// "=== CONT  "
-	actionColon := false
 	origLine := line
 	ok := false
 	indent := 0
@@ -273,7 +274,6 @@ func (c *Converter) handleInputLine(line []byte) {
 		}
 		for _, magic := range reports {
 			if bytes.HasPrefix(line, magic) {
-				actionColon = true
 				ok = true
 				break
 			}
@@ -296,16 +296,11 @@ func (c *Converter) handleInputLine(line []byte) {
 		return
 	}
 
-	// Parse out action and test name.
-	i := 0
-	if actionColon {
-		i = bytes.IndexByte(line, ':') + 1
-	}
-	if i == 0 {
-		i = len(updates[0])
-	}
-	action := strings.ToLower(strings.TrimSuffix(strings.TrimSpace(string(line[4:i])), ":"))
-	name := strings.TrimSpace(string(line[i:]))
+	// Parse out action and test name from "=== ACTION: Name".
+	action, name, _ := strings.Cut(string(line[len("=== "):]), " ")
+	action = strings.TrimSuffix(action, ":")
+	action = strings.ToLower(action)
+	name = strings.TrimSpace(name)
 
 	e := &event{Action: action}
 	if line[0] == '-' { // PASS or FAIL report
@@ -336,7 +331,10 @@ func (c *Converter) handleInputLine(line []byte) {
 		c.output.write(origLine)
 		return
 	}
-	if action == "attr" {
+	switch action {
+	case "artifacts":
+		name, e.Path, _ = strings.Cut(name, " ")
+	case "attr":
 		var rest string
 		name, rest, _ = strings.Cut(name, " ")
 		e.Key, e.Value, _ = strings.Cut(rest, " ")
diff --git a/src/testing/internal/testdeps/deps.go b/src/testing/internal/testdeps/deps.go
index 6f42d4722ca00c..5ab377daeb61ed 100644
--- a/src/testing/internal/testdeps/deps.go
+++ b/src/testing/internal/testdeps/deps.go
@@ -66,6 +66,12 @@ func (TestDeps) ImportPath() string {
 	return ImportPath
 }
 
+var ModulePath string
+
+func (TestDeps) ModulePath() string {
+	return ModulePath
+}
+
 // testLog implements testlog.Interface, logging actions by package os.
 type testLog struct {
 	mu  sync.Mutex
diff --git a/src/testing/testing.go b/src/testing/testing.go
index 3f76446549364a..0d1d08ca89a5e6 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -420,7 +420,6 @@ import (
 	"sync/atomic"
 	"time"
 	"unicode"
-	"unicode/utf8"
 	_ "unsafe" // for linkname
 )
 
@@ -456,6 +455,7 @@ func Init() {
 	// this flag lets "go test" tell the binary to write the files in the directory where
 	// the "go test" command is run.
 	outputDir = flag.String("test.outputdir", "", "write profiles to `dir`")
+	artifacts = flag.Bool("test.artifacts", false, "store test artifacts in test.,outputdir")
 	// Report as tests are run; default is silent for success.
 	flag.Var(&chatty, "test.v", "verbose: print additional output")
 	count = flag.Uint("test.count", 1, "run tests and benchmarks `n` times")
@@ -489,6 +489,7 @@ var (
 	short                *bool
 	failFast             *bool
 	outputDir            *string
+	artifacts            *bool
 	chatty               chattyFlag
 	count                *uint
 	coverProfile         *string
@@ -516,6 +517,7 @@ var (
 
 	cpuList     []int
 	testlogFile *os.File
+	artifactDir string
 
 	numFailed atomic.Uint32 // number of test failures
 
@@ -653,15 +655,17 @@ type common struct {
 	runner         string         // Function name of tRunner running the test.
 	isParallel     bool           // Whether the test is parallel.
 
-	parent   *common
-	level    int               // Nesting depth of test or benchmark.
-	creator  []uintptr         // If level > 0, the stack trace at the point where the parent called t.Run.
-	name     string            // Name of test or benchmark.
-	start    highPrecisionTime // Time test or benchmark started
-	duration time.Duration
-	barrier  chan bool // To signal parallel subtests they may start. Nil when T.Parallel is not present (B) or not usable (when fuzzing).
-	signal   chan bool // To signal a test is done.
-	sub      []*T      // Queue of subtests to be run in parallel.
+	parent     *common
+	level      int       // Nesting depth of test or benchmark.
+	creator    []uintptr // If level > 0, the stack trace at the point where the parent called t.Run.
+	modulePath string
+	importPath string
+	name       string            // Name of test or benchmark.
+	start      highPrecisionTime // Time test or benchmark started
+	duration   time.Duration
+	barrier    chan bool // To signal parallel subtests they may start. Nil when T.Parallel is not present (B) or not usable (when fuzzing).
+	signal     chan bool // To signal a test is done.
+	sub        []*T      // Queue of subtests to be run in parallel.
 
 	lastRaceErrors  atomic.Int64 // Max value of race.Errors seen during the test or its subtests.
 	raceErrorLogged atomic.Bool
@@ -671,6 +675,10 @@ type common struct {
 	tempDirErr error
 	tempDirSeq int32
 
+	artifactDirOnce sync.Once
+	artifactDir     string
+	artifactDirErr  error
+
 	ctx       context.Context
 	cancelCtx context.CancelFunc
 }
@@ -879,6 +887,7 @@ func fmtDuration(d time.Duration) string {
 
 // TB is the interface common to [T], [B], and [F].
 type TB interface {
+	ArtifactDir() string
 	Attr(key, value string)
 	Cleanup(func())
 	Error(args ...any)
@@ -1313,6 +1322,96 @@ func (c *common) Cleanup(f func()) {
 	c.cleanups = append(c.cleanups, fn)
 }
 
+// ArtifactDir returns a directory in which the test should store output files.
+// When the -artifacts flag is provided, this directory is located
+// under the output directory. Otherwise, ArtifactDir returns a temporary directory
+// that is removed after the test completes.
+//
+// Each test or subtest within each test package has a unique artifact directory.
+// Repeated calls to ArtifactDir in the same test or subtest return the same directory.
+// Subtest outputs are not located under the parent test's output directory.
+func (c *common) ArtifactDir() string {
+	c.checkFuzzFn("ArtifactDir")
+	c.artifactDirOnce.Do(func() {
+		c.artifactDir, c.artifactDirErr = c.makeArtifactDir()
+	})
+	if c.artifactDirErr != nil {
+		c.Fatalf("ArtifactDir: %v", c.artifactDirErr)
+	}
+	return c.artifactDir
+}
+
+func hashString(s string) (h uint64) {
+	// FNV, used here to avoid a dependency on maphash.
+	for i := 0; i < len(s); i++ {
+		h ^= uint64(s[i])
+		h *= 1099511628211
+	}
+	return
+}
+
+// makeArtifactDir creates the artifact directory for a test.
+// The artifact directory is:
+//
+//	/_artifacts///
+//
+// The test package is the package import path with the module name prefix removed.
+// The test name is truncated if too long.
+// Special characters are removed from the path.
+func (c *common) makeArtifactDir() (string, error) {
+	if !*artifacts {
+		return c.makeTempDir()
+	}
+
+	// If the test name is longer than maxNameSize, truncate it and replace the last
+	// hashSize bytes with a hash of the full name.
+	const maxNameSize = 64
+	name := strings.ReplaceAll(c.name, "/", "__")
+	if len(name) > maxNameSize {
+		h := fmt.Sprintf("%0x", hashString(name))
+		name = name[:maxNameSize-len(h)] + h
+	}
+
+	// Remove the module path prefix from the import path.
+	pkg := strings.TrimPrefix(c.importPath, c.modulePath+"/")
+
+	// Join with /, not filepath.Join: the import path is /-separated,
+	// and we don't want removeSymbolsExcept to strip \ separators on Windows.
+	base := "/" + pkg + "/" + name
+	base = removeSymbolsExcept(base, "!#$%&()+,-.=@^_{}~ /")
+	base, err := filepath.Localize(base)
+	if err != nil {
+		// This name can't be safely converted into a local filepath.
+		// Drop it and just use _artifacts/.
+		base = ""
+	}
+
+	artifactBase := filepath.Join(artifactDir, base)
+	if err := os.MkdirAll(artifactBase, 0o777); err != nil {
+		return "", err
+	}
+	dir, err := os.MkdirTemp(artifactBase, "")
+	if err != nil {
+		return "", err
+	}
+	if c.chatty != nil {
+		c.chatty.Updatef(c.name, "=== ARTIFACTS %s %v\n", c.name, dir)
+	}
+	return dir, nil
+}
+
+func removeSymbolsExcept(s, allowed string) string {
+	mapper := func(r rune) rune {
+		if unicode.IsLetter(r) ||
+			unicode.IsNumber(r) ||
+			strings.ContainsRune(allowed, r) {
+			return r
+		}
+		return -1 // disallowed symbol
+	}
+	return strings.Map(mapper, s)
+}
+
 // TempDir returns a temporary directory for the test to use.
 // The directory is automatically removed when the test and
 // all its subtests complete.
@@ -1322,6 +1421,14 @@ func (c *common) Cleanup(f func()) {
 // be created somewhere beneath it.
 func (c *common) TempDir() string {
 	c.checkFuzzFn("TempDir")
+	dir, err := c.makeTempDir()
+	if err != nil {
+		c.Fatalf("TempDir: %v", err)
+	}
+	return dir
+}
+
+func (c *common) makeTempDir() (string, error) {
 	// Use a single parent directory for all the temporary directories
 	// created by a test, each numbered sequentially.
 	c.tempDirMu.Lock()
@@ -1332,7 +1439,7 @@ func (c *common) TempDir() string {
 		_, err := os.Stat(c.tempDir)
 		nonExistent = os.IsNotExist(err)
 		if err != nil && !nonExistent {
-			c.Fatalf("TempDir: %v", err)
+			return "", err
 		}
 	}
 
@@ -1347,23 +1454,9 @@ func (c *common) TempDir() string {
 		// Drop unusual characters (such as path separators or
 		// characters interacting with globs) from the directory name to
 		// avoid surprising os.MkdirTemp behavior.
-		mapper := func(r rune) rune {
-			if r < utf8.RuneSelf {
-				const allowed = "!#$%&()+,-.=@^_{}~ "
-				if '0' <= r && r <= '9' ||
-					'a' <= r && r <= 'z' ||
-					'A' <= r && r <= 'Z' {
-					return r
-				}
-				if strings.ContainsRune(allowed, r) {
-					return r
-				}
-			} else if unicode.IsLetter(r) || unicode.IsNumber(r) {
-				return r
-			}
-			return -1
-		}
-		pattern = strings.Map(mapper, pattern)
+		const allowed = "!#$%&()+,-.=@^_{}~ "
+		pattern = removeSymbolsExcept(pattern, allowed)
+
 		c.tempDir, c.tempDirErr = os.MkdirTemp(os.Getenv("GOTMPDIR"), pattern)
 		if c.tempDirErr == nil {
 			c.Cleanup(func() {
@@ -1381,14 +1474,14 @@ func (c *common) TempDir() string {
 	c.tempDirMu.Unlock()
 
 	if c.tempDirErr != nil {
-		c.Fatalf("TempDir: %v", c.tempDirErr)
+		return "", c.tempDirErr
 	}
 
 	dir := fmt.Sprintf("%s%c%03d", c.tempDir, os.PathSeparator, seq)
 	if err := os.Mkdir(dir, 0o777); err != nil {
-		c.Fatalf("TempDir: %v", err)
+		return "", err
 	}
-	return dir
+	return dir, nil
 }
 
 // removeAll is like os.RemoveAll, but retries Windows "Access is denied."
@@ -1971,15 +2064,17 @@ func (t *T) Run(name string, f func(t *T)) bool {
 	ctx, cancelCtx := context.WithCancel(context.Background())
 	t = &T{
 		common: common{
-			barrier:   make(chan bool),
-			signal:    make(chan bool, 1),
-			name:      testName,
-			parent:    &t.common,
-			level:     t.level + 1,
-			creator:   pc[:n],
-			chatty:    t.chatty,
-			ctx:       ctx,
-			cancelCtx: cancelCtx,
+			barrier:    make(chan bool),
+			signal:     make(chan bool, 1),
+			name:       testName,
+			modulePath: t.modulePath,
+			importPath: t.importPath,
+			parent:     &t.common,
+			level:      t.level + 1,
+			creator:    pc[:n],
+			chatty:     t.chatty,
+			ctx:        ctx,
+			cancelCtx:  cancelCtx,
 		},
 		tstate: t.tstate,
 	}
@@ -2140,6 +2235,7 @@ func (f matchStringOnly) MatchString(pat, str string) (bool, error)   { return f
 func (f matchStringOnly) StartCPUProfile(w io.Writer) error           { return errMain }
 func (f matchStringOnly) StopCPUProfile()                             {}
 func (f matchStringOnly) WriteProfileTo(string, io.Writer, int) error { return errMain }
+func (f matchStringOnly) ModulePath() string                          { return "" }
 func (f matchStringOnly) ImportPath() string                          { return "" }
 func (f matchStringOnly) StartTestLog(io.Writer)                      {}
 func (f matchStringOnly) StopTestLog() error                          { return errMain }
@@ -2193,6 +2289,7 @@ type M struct {
 // testing/internal/testdeps's TestDeps.
 type testDeps interface {
 	ImportPath() string
+	ModulePath() string
 	MatchString(pat, str string) (bool, error)
 	SetPanicOnExit0(bool)
 	StartCPUProfile(io.Writer) error
@@ -2336,7 +2433,7 @@ func (m *M) Run() (code int) {
 	if !*isFuzzWorker {
 		deadline := m.startAlarm()
 		haveExamples = len(m.examples) > 0
-		testRan, testOk := runTests(m.deps.MatchString, m.tests, deadline)
+		testRan, testOk := runTests(m.deps.ModulePath(), m.deps.ImportPath(), m.deps.MatchString, m.tests, deadline)
 		fuzzTargetsRan, fuzzTargetsOk := runFuzzTests(m.deps, m.fuzzTargets, deadline)
 		exampleRan, exampleOk := runExamples(m.deps.MatchString, m.examples)
 		m.stopAlarm()
@@ -2437,14 +2534,14 @@ func RunTests(matchString func(pat, str string) (bool, error), tests []InternalT
 	if *timeout > 0 {
 		deadline = time.Now().Add(*timeout)
 	}
-	ran, ok := runTests(matchString, tests, deadline)
+	ran, ok := runTests("", "", matchString, tests, deadline)
 	if !ran && !haveExamples {
 		fmt.Fprintln(os.Stderr, "testing: warning: no tests to run")
 	}
 	return ok
 }
 
-func runTests(matchString func(pat, str string) (bool, error), tests []InternalTest, deadline time.Time) (ran, ok bool) {
+func runTests(modulePath, importPath string, matchString func(pat, str string) (bool, error), tests []InternalTest, deadline time.Time) (ran, ok bool) {
 	ok = true
 	for _, procs := range cpuList {
 		runtime.GOMAXPROCS(procs)
@@ -2463,11 +2560,13 @@ func runTests(matchString func(pat, str string) (bool, error), tests []InternalT
 			tstate.deadline = deadline
 			t := &T{
 				common: common{
-					signal:    make(chan bool, 1),
-					barrier:   make(chan bool),
-					w:         os.Stdout,
-					ctx:       ctx,
-					cancelCtx: cancelCtx,
+					signal:     make(chan bool, 1),
+					barrier:    make(chan bool),
+					w:          os.Stdout,
+					ctx:        ctx,
+					cancelCtx:  cancelCtx,
+					modulePath: modulePath,
+					importPath: importPath,
 				},
 				tstate: tstate,
 			}
@@ -2536,6 +2635,18 @@ func (m *M) before() {
 		fmt.Fprintf(os.Stderr, "testing: cannot use -test.gocoverdir because test binary was not built with coverage enabled\n")
 		os.Exit(2)
 	}
+	if *artifacts {
+		var err error
+		artifactDir, err = filepath.Abs(toOutputDir("_artifacts"))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "testing: cannot make -test.outputdir absolute: %v\n", err)
+			os.Exit(2)
+		}
+		if err := os.Mkdir(artifactDir, 0o777); err != nil && !errors.Is(err, os.ErrExist) {
+			fmt.Fprintf(os.Stderr, "testing: %v\n", err)
+			os.Exit(2)
+		}
+	}
 	if *testlog != "" {
 		// Note: Not using toOutputDir.
 		// This file is for use by cmd/go, not users.
diff --git a/src/testing/testing_test.go b/src/testing/testing_test.go
index cc89e4144e6a78..167f4a0b457635 100644
--- a/src/testing/testing_test.go
+++ b/src/testing/testing_test.go
@@ -469,7 +469,7 @@ func TestTesting(t *testing.T) {
 
 // runTest runs a helper test with -test.v, ignoring its exit status.
 // runTest both logs and returns the test output.
-func runTest(t *testing.T, test string) []byte {
+func runTest(t *testing.T, test string, args ...string) []byte {
 	t.Helper()
 
 	testenv.MustHaveExec(t)
@@ -477,6 +477,7 @@ func runTest(t *testing.T, test string) []byte {
 	cmd := testenv.Command(t, testenv.Executable(t), "-test.run=^"+test+"$", "-test.bench="+test, "-test.v", "-test.parallel=2", "-test.benchtime=2x")
 	cmd = testenv.CleanCmdEnv(cmd)
 	cmd.Env = append(cmd.Env, "GO_WANT_HELPER_PROCESS=1")
+	cmd.Args = append(cmd.Args, args...)
 	out, err := cmd.CombinedOutput()
 	t.Logf("%v: %v\n%s", cmd, err, out)
 
@@ -1055,6 +1056,105 @@ func TestAttrInvalid(t *testing.T) {
 	}
 }
 
+const artifactContent = "It belongs in a museum.\n"
+
+func TestArtifactDirExample(t *testing.T) {
+	os.WriteFile(filepath.Join(t.ArtifactDir(), "artifact"), []byte(artifactContent), 0o666)
+}
+
+func TestArtifactDirDefault(t *testing.T) {
+	tempDir := t.TempDir()
+	t.Chdir(tempDir)
+	out := runTest(t, "TestArtifactDirExample", "-test.artifacts")
+	checkArtifactDir(t, out, "TestArtifactDirExample", tempDir)
+}
+
+func TestArtifactDirSpecified(t *testing.T) {
+	tempDir := t.TempDir()
+	out := runTest(t, "TestArtifactDirExample", "-test.artifacts", "-test.outputdir="+tempDir)
+	checkArtifactDir(t, out, "TestArtifactDirExample", tempDir)
+}
+
+func TestArtifactDirNoArtifacts(t *testing.T) {
+	t.Chdir(t.TempDir())
+	out := string(runTest(t, "TestArtifactDirExample"))
+	if strings.Contains(out, "=== ARTIFACTS") {
+		t.Errorf("expected output with no === ARTIFACTS, got\n%q", out)
+	}
+	ents, err := os.ReadDir(".")
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, e := range ents {
+		t.Errorf("unexpected file in current directory after test: %v", e.Name())
+	}
+}
+
+func TestArtifactDirSubtestExample(t *testing.T) {
+	t.Run("Subtest", func(t *testing.T) {
+		os.WriteFile(filepath.Join(t.ArtifactDir(), "artifact"), []byte(artifactContent), 0o666)
+	})
+}
+
+func TestArtifactDirInSubtest(t *testing.T) {
+	tempDir := t.TempDir()
+	out := runTest(t, "TestArtifactDirSubtestExample/Subtest", "-test.artifacts", "-test.outputdir="+tempDir)
+	checkArtifactDir(t, out, "TestArtifactDirSubtestExample/Subtest", tempDir)
+}
+
+func TestArtifactDirLongTestNameExample(t *testing.T) {
+	name := strings.Repeat("x", 256)
+	t.Run(name, func(t *testing.T) {
+		os.WriteFile(filepath.Join(t.ArtifactDir(), "artifact"), []byte(artifactContent), 0o666)
+	})
+}
+
+func TestArtifactDirWithLongTestName(t *testing.T) {
+	tempDir := t.TempDir()
+	out := runTest(t, "TestArtifactDirLongTestNameExample", "-test.artifacts", "-test.outputdir="+tempDir)
+	checkArtifactDir(t, out, `TestArtifactDirLongTestNameExample/\w+`, tempDir)
+}
+
+func TestArtifactDirConsistent(t *testing.T) {
+	a := t.ArtifactDir()
+	b := t.ArtifactDir()
+	if a != b {
+		t.Errorf("t.ArtifactDir is not consistent between calls: %q, %q", a, b)
+	}
+}
+
+func checkArtifactDir(t *testing.T, out []byte, testName, outputDir string) {
+	t.Helper()
+
+	re := regexp.MustCompile(`=== ARTIFACTS ` + testName + ` ([^\n]+)`)
+	match := re.FindSubmatch(out)
+	if match == nil {
+		t.Fatalf("expected output matching %q, got\n%q", re, out)
+	}
+	artifactDir := string(match[1])
+
+	// Verify that the artifact directory is contained in the expected output directory.
+	relDir, err := filepath.Rel(outputDir, artifactDir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !filepath.IsLocal(relDir) {
+		t.Fatalf("want artifact directory contained in %q, got %q", outputDir, artifactDir)
+	}
+
+	for _, part := range strings.Split(relDir, string(os.PathSeparator)) {
+		const maxSize = 64
+		if len(part) > maxSize {
+			t.Errorf("artifact directory %q contains component >%v characters long: %q", relDir, maxSize, part)
+		}
+	}
+
+	got, err := os.ReadFile(filepath.Join(artifactDir, "artifact"))
+	if err != nil || string(got) != artifactContent {
+		t.Errorf("reading artifact in %q: got %q, %v; want %q", artifactDir, got, err, artifactContent)
+	}
+}
+
 func TestBenchmarkBLoopIterationCorrect(t *testing.T) {
 	out := runTest(t, "BenchmarkBLoopPrint")
 	c := bytes.Count(out, []byte("Printing from BenchmarkBLoopPrint"))
@@ -1110,3 +1210,7 @@ func BenchmarkBNPrint(b *testing.B) {
 		b.Logf("Printing from BenchmarkBNPrint")
 	}
 }
+
+func TestArtifactDir(t *testing.T) {
+	t.Log(t.ArtifactDir())
+}

From 78b43037dc20b9f5d624260b50e15bfa8956e4d5 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 21:21:41 -0400
Subject: [PATCH 095/229] cmd/go: refactor usage of `workFilePath`

This commit refactors usage of the global variable `workFilePath` to
the global LoaderState field of the same name.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf 'ex { workFilePath -> LoaderState.workFilePath }'
rf 'add State.requirements \
// Set to the path to the go.work file, or "" if workspace mode is\
// disabled'
rf 'rm workFilePath'

Change-Id: I53cdbc3cc619914421513db74a74a04ab10b3e33
Reviewed-on: https://go-review.googlesource.com/c/go/+/698062
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/modload/buildlist.go |  4 +--
 src/cmd/go/internal/modload/init.go      | 31 +++++++++++-------------
 src/cmd/go/internal/modload/modfile.go   |  2 +-
 3 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/src/cmd/go/internal/modload/buildlist.go b/src/cmd/go/internal/modload/buildlist.go
index b73cb43d0dc3cf..086626042c95b7 100644
--- a/src/cmd/go/internal/modload/buildlist.go
+++ b/src/cmd/go/internal/modload/buildlist.go
@@ -108,13 +108,13 @@ func newRequirements(pruning modPruning, rootModules []module.Version, direct ma
 	mustHaveGoRoot(rootModules)
 
 	if pruning != workspace {
-		if workFilePath != "" {
+		if LoaderState.workFilePath != "" {
 			panic("in workspace mode, but pruning is not workspace in newRequirements")
 		}
 	}
 
 	if pruning != workspace {
-		if workFilePath != "" {
+		if LoaderState.workFilePath != "" {
 			panic("in workspace mode, but pruning is not workspace in newRequirements")
 		}
 		for i, m := range rootModules {
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 1c8aa379d3cf78..31fe6327735736 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -60,7 +60,7 @@ var (
 func EnterModule(ctx context.Context, enterModroot string) {
 	LoaderState.MainModules = nil // reset MainModules
 	LoaderState.requirements = nil
-	workFilePath = "" // Force module mode
+	LoaderState.workFilePath = "" // Force module mode
 	modfetch.Reset()
 
 	LoaderState.modRoots = []string{enterModroot}
@@ -97,12 +97,6 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	}, nil
 }
 
-// Variable set in InitWorkfile
-var (
-	// Set to the path to the go.work file, or "" if workspace mode is disabled.
-	workFilePath string
-)
-
 type MainModuleSet struct {
 	// versions are the module.Version values of each of the main modules.
 	// For each of them, the Path fields are ordinary module paths and the Version
@@ -349,7 +343,7 @@ func InitWorkfile() {
 	if err := fsys.Init(); err != nil {
 		base.Fatal(err)
 	}
-	workFilePath = FindGoWork(base.Cwd())
+	LoaderState.workFilePath = FindGoWork(base.Cwd())
 }
 
 // FindGoWork returns the name of the go.work file for this command,
@@ -378,7 +372,7 @@ func FindGoWork(wd string) string {
 // WorkFilePath returns the absolute path of the go.work file, or "" if not in
 // workspace mode. WorkFilePath must be called after InitWorkfile.
 func WorkFilePath() string {
-	return workFilePath
+	return LoaderState.workFilePath
 }
 
 // Reset clears all the initialized, cached state about the use of modules,
@@ -404,7 +398,7 @@ func setState(s State) State {
 	cfg.ModulesEnabled = s.modulesEnabled
 	LoaderState.MainModules = s.MainModules
 	LoaderState.requirements = s.requirements
-	workFilePath = s.workFilePath
+	LoaderState.workFilePath = s.workFilePath
 	// The modfetch package's global state is used to compute
 	// the go.sum file, so save and restore it along with the
 	// modload state.
@@ -441,7 +435,10 @@ type State struct {
 	// commitRequirements functions.  All other functions that need or
 	// produce a *Requirements should accept and/or return an explicit
 	// parameter.
-	requirements  *Requirements
+	requirements *Requirements
+
+	// Set to the path to the go.work file, or "" if workspace mode is
+	// disabled
 	workFilePath  string
 	modfetchState modfetch.State
 }
@@ -507,7 +504,7 @@ func Init() {
 			base.Fatalf("go: -modfile cannot be used with commands that ignore the current module")
 		}
 		LoaderState.modRoots = nil
-	} else if workFilePath != "" {
+	} else if LoaderState.workFilePath != "" {
 		// We're in workspace mode, which implies module mode.
 		if cfg.ModFile != "" {
 			base.Fatalf("go: -modfile cannot be used in workspace mode")
@@ -651,7 +648,7 @@ func inWorkspaceMode() bool {
 	if !Enabled() {
 		return false
 	}
-	return workFilePath != ""
+	return LoaderState.workFilePath != ""
 }
 
 // HasModRoot reports whether a main module or main modules are present.
@@ -888,7 +885,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 	var workFile *modfile.WorkFile
 	if inWorkspaceMode() {
 		var err error
-		workFile, LoaderState.modRoots, err = LoadWorkFile(workFilePath)
+		workFile, LoaderState.modRoots, err = LoadWorkFile(LoaderState.workFilePath)
 		if err != nil {
 			return nil, err
 		}
@@ -896,7 +893,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			sumFile := strings.TrimSuffix(modFilePath(modRoot), ".mod") + ".sum"
 			modfetch.WorkspaceGoSumFiles = append(modfetch.WorkspaceGoSumFiles, sumFile)
 		}
-		modfetch.GoSumFile = workFilePath + ".sum"
+		modfetch.GoSumFile = LoaderState.workFilePath + ".sum"
 	} else if len(LoaderState.modRoots) == 0 {
 		// We're in module mode, but not inside a module.
 		//
@@ -1542,8 +1539,8 @@ func setDefaultBuildMod() {
 			}
 		}
 		vendorDir := ""
-		if workFilePath != "" {
-			vendorDir = filepath.Join(filepath.Dir(workFilePath), "vendor")
+		if LoaderState.workFilePath != "" {
+			vendorDir = filepath.Join(filepath.Dir(LoaderState.workFilePath), "vendor")
 		} else {
 			if len(LoaderState.modRoots) != 1 {
 				panic(fmt.Errorf("outside workspace mode, but have %v modRoots", LoaderState.modRoots))
diff --git a/src/cmd/go/internal/modload/modfile.go b/src/cmd/go/internal/modload/modfile.go
index 6b432ed9637ec5..fa2348d97baf25 100644
--- a/src/cmd/go/internal/modload/modfile.go
+++ b/src/cmd/go/internal/modload/modfile.go
@@ -356,7 +356,7 @@ func replacementFrom(mod module.Version) (r module.Version, modroot string, from
 		return module.Version{}, "", ""
 	}
 	if _, r, ok := replacement(mod, LoaderState.MainModules.WorkFileReplaceMap()); ok {
-		return r, "", workFilePath
+		return r, "", LoaderState.workFilePath
 	}
 	for _, v := range LoaderState.MainModules.Versions() {
 		if index := LoaderState.MainModules.Index(v); index != nil {

From 97fd6bdeccf8c59f07dadbff8f614ea4169f01b1 Mon Sep 17 00:00:00 2001
From: Michael Munday 
Date: Mon, 18 Aug 2025 22:51:36 +0100
Subject: [PATCH 096/229] cmd/compile: fuse NaN checks with other comparisons
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

NaN checks can often be merged into other comparisons by inverting them.
For example, `math.IsNaN(x) || x > 0` is equivalent to `!(x <= 0)`.

goos: linux
goarch: amd64
pkg: math
cpu: 12th Gen Intel(R) Core(TM) i7-12700T
            │         sec/op         │    sec/op     vs base                │
Acos                     4.315n ± 0%    4.314n ± 0%        ~ (p=0.642 n=10)
Acosh                    8.398n ± 0%    7.779n ± 0%   -7.37% (p=0.000 n=10)
Asin                     4.203n ± 0%    4.211n ± 0%   +0.20% (p=0.001 n=10)
Asinh                   10.150n ± 0%    9.562n ± 0%   -5.79% (p=0.000 n=10)
Atan                     2.363n ± 0%    2.363n ± 0%        ~ (p=0.801 n=10)
Atanh                    8.192n ± 2%    7.685n ± 0%   -6.20% (p=0.000 n=10)
Atan2                    4.013n ± 0%    4.010n ± 0%        ~ (p=0.073 n=10)
Cbrt                     4.858n ± 0%    4.755n ± 0%   -2.12% (p=0.000 n=10)
Cos                      4.596n ± 0%    4.357n ± 0%   -5.20% (p=0.000 n=10)
Cosh                     5.071n ± 0%    5.071n ± 0%        ~ (p=0.585 n=10)
Erf                      2.802n ± 1%    2.788n ± 0%   -0.54% (p=0.002 n=10)
Erfc                     3.087n ± 1%    3.071n ± 0%        ~ (p=0.320 n=10)
Erfinv                   3.981n ± 0%    3.965n ± 0%   -0.41% (p=0.000 n=10)
Erfcinv                  3.985n ± 0%    3.977n ± 0%   -0.20% (p=0.000 n=10)
ExpGo                    8.721n ± 2%    8.252n ± 0%   -5.38% (p=0.000 n=10)
Expm1                    4.378n ± 0%    4.228n ± 0%   -3.43% (p=0.000 n=10)
Exp2                     8.313n ± 0%    7.855n ± 0%   -5.52% (p=0.000 n=10)
Exp2Go                   8.498n ± 2%    7.921n ± 0%   -6.79% (p=0.000 n=10)
Mod                      15.16n ± 4%    12.20n ± 1%  -19.58% (p=0.000 n=10)
Frexp                    1.780n ± 2%    1.496n ± 0%  -15.96% (p=0.000 n=10)
Gamma                    4.378n ± 1%    4.013n ± 0%   -8.35% (p=0.000 n=10)
HypotGo                  2.655n ± 5%    2.427n ± 1%   -8.57% (p=0.000 n=10)
Ilogb                    1.912n ± 5%    1.749n ± 0%   -8.53% (p=0.000 n=10)
J0                       22.43n ± 9%    20.46n ± 0%   -8.76% (p=0.000 n=10)
J1                       21.03n ± 4%    19.96n ± 0%   -5.09% (p=0.000 n=10)
Jn                       45.40n ± 1%    42.59n ± 0%   -6.20% (p=0.000 n=10)
Ldexp                    2.312n ± 1%    1.944n ± 0%  -15.94% (p=0.000 n=10)
Lgamma                   4.617n ± 1%    4.584n ± 0%   -0.73% (p=0.000 n=10)
Log                      4.226n ± 0%    4.213n ± 0%   -0.31% (p=0.001 n=10)
Logb                     1.771n ± 0%    1.775n ± 0%        ~ (p=0.097 n=10)
Log1p                    5.102n ± 2%    5.001n ± 0%   -1.97% (p=0.000 n=10)
Log10                    4.407n ± 0%    4.408n ± 0%        ~ (p=1.000 n=10)
Log2                     2.416n ± 1%    2.138n ± 0%  -11.51% (p=0.000 n=10)
Modf                     1.669n ± 2%    1.611n ± 0%   -3.50% (p=0.000 n=10)
Nextafter32              2.186n ± 0%    2.185n ± 0%        ~ (p=0.051 n=10)
Nextafter64              2.182n ± 0%    2.184n ± 0%   +0.09% (p=0.016 n=10)
PowInt                   11.39n ± 6%    10.68n ± 2%   -6.24% (p=0.000 n=10)
PowFrac                  26.60n ± 2%    26.12n ± 0%   -1.80% (p=0.000 n=10)
Pow10Pos                0.5067n ± 4%   0.5003n ± 1%   -1.27% (p=0.001 n=10)
Pow10Neg                0.8552n ± 0%   0.8552n ± 0%        ~ (p=0.928 n=10)
Round                    1.181n ± 0%    1.182n ± 0%   +0.08% (p=0.001 n=10)
RoundToEven              1.709n ± 0%    1.710n ± 0%        ~ (p=0.053 n=10)
Remainder                12.54n ± 5%    11.99n ± 2%   -4.46% (p=0.000 n=10)
Sin                      3.933n ± 5%    3.926n ± 0%   -0.17% (p=0.000 n=10)
Sincos                   5.672n ± 0%    5.522n ± 0%   -2.65% (p=0.000 n=10)
Sinh                     5.447n ± 1%    5.444n ± 0%   -0.06% (p=0.029 n=10)
Tan                      4.061n ± 0%    4.058n ± 0%   -0.07% (p=0.005 n=10)
Tanh                     5.599n ± 0%    5.595n ± 0%   -0.06% (p=0.042 n=10)
Y0                       20.75n ± 5%    19.73n ± 1%   -4.92% (p=0.000 n=10)
Y1                       20.87n ± 2%    19.78n ± 1%   -5.20% (p=0.000 n=10)
Yn                       44.50n ± 2%    42.04n ± 2%   -5.53% (p=0.000 n=10)
geomean                  4.989n         4.791n        -3.96%

goos: linux
goarch: riscv64
pkg: math
cpu: Spacemit(R) X60
                    │     sec/op     │    sec/op     vs base                  │
Acos                    159.9n ±  0%   159.9n ±  0%        ~ (p=0.269 n=10)
Acosh                   244.7n ±  0%   235.0n ±  0%   -3.98% (p=0.000 n=10)
Asin                    159.9n ±  0%   159.9n ±  0%        ~ (p=0.154 n=10)
Asinh                   270.8n ±  0%   261.1n ±  0%   -3.60% (p=0.000 n=10)
Atan                    119.1n ±  0%   119.1n ±  0%        ~ (p=0.347 n=10)
Atanh                   260.2n ±  0%   261.8n ±  4%        ~ (p=0.459 n=10)
Atan2                   186.8n ±  0%   186.8n ±  0%        ~ (p=0.487 n=10)
Cbrt                    203.5n ±  0%   198.2n ±  0%   -2.60% (p=0.000 n=10)
Ceil                    31.82n ±  0%   31.81n ±  0%        ~ (p=0.714 n=10)
Copysign                4.894n ±  0%   4.893n ±  0%        ~ (p=0.161 n=10)
Cos                     107.6n ±  0%   103.6n ±  0%   -3.76% (p=0.000 n=10)
Cosh                    259.0n ±  0%   252.8n ±  0%   -2.39% (p=0.000 n=10)
Erf                     133.7n ±  0%   133.7n ±  0%        ~ (p=0.720 n=10)
Erfc                    137.9n ±  0%   137.8n ±  0%   -0.04% (p=0.033 n=10)
Erfinv                  173.7n ±  0%   168.8n ±  0%   -2.82% (p=0.000 n=10)
Erfcinv                 173.7n ±  0%   168.8n ±  0%   -2.82% (p=0.000 n=10)
Exp                     215.3n ±  0%   208.1n ±  0%   -3.34% (p=0.000 n=10)
ExpGo                   226.7n ±  0%   220.6n ±  0%   -2.69% (p=0.000 n=10)
Expm1                   164.8n ±  0%   159.0n ±  0%   -3.52% (p=0.000 n=10)
Exp2                    185.0n ±  0%   182.7n ±  0%   -1.22% (p=0.000 n=10)
Exp2Go                  198.9n ±  0%   196.5n ±  0%   -1.21% (p=0.000 n=10)
Abs                     4.894n ±  0%   4.893n ±  0%        ~ (p=0.262 n=10)
Dim                     16.31n ±  0%   16.31n ±  0%        ~ (p=1.000 n=10)
Floor                   31.81n ±  0%   31.81n ±  0%        ~ (p=0.067 n=10)
Max                     26.11n ±  0%   26.10n ±  0%        ~ (p=0.080 n=10)
Min                     26.10n ±  0%   26.10n ±  0%        ~ (p=0.095 n=10)
Mod                     337.7n ±  0%   291.9n ±  0%  -13.56% (p=0.000 n=10)
Frexp                   50.57n ±  0%   42.41n ±  0%  -16.13% (p=0.000 n=10)
Gamma                   206.3n ±  0%   198.1n ±  0%   -4.00% (p=0.000 n=10)
Hypot                   94.62n ±  0%   94.61n ±  0%        ~ (p=0.437 n=10)
HypotGo                 109.3n ±  0%   109.3n ±  0%        ~ (p=1.000 n=10)
Ilogb                   44.05n ±  0%   44.04n ±  0%   -0.02% (p=0.025 n=10)
J0                      663.1n ±  0%   663.9n ±  0%   +0.13% (p=0.002 n=10)
J1                      663.9n ±  0%   666.4n ±  0%   +0.38% (p=0.000 n=10)
Jn                      1.404µ ±  0%   1.407µ ±  0%   +0.21% (p=0.000 n=10)
Ldexp                   57.10n ±  0%   48.93n ±  0%  -14.30% (p=0.000 n=10)
Lgamma                  185.1n ±  0%   187.6n ±  0%   +1.32% (p=0.000 n=10)
Log                     182.7n ±  0%   170.1n ±  0%   -6.87% (p=0.000 n=10)
Logb                    46.49n ±  0%   46.49n ±  0%        ~ (p=0.675 n=10)
Log1p                   184.3n ±  0%   179.4n ±  0%   -2.63% (p=0.000 n=10)
Log10                   184.3n ±  0%   171.2n ±  0%   -7.08% (p=0.000 n=10)
Log2                    66.05n ±  0%   57.90n ±  0%  -12.34% (p=0.000 n=10)
Modf                    34.25n ±  0%   34.24n ±  0%        ~ (p=0.163 n=10)
Nextafter32             49.33n ±  1%   48.93n ±  0%   -0.81% (p=0.002 n=10)
Nextafter64             43.64n ±  0%   43.23n ±  0%   -0.93% (p=0.000 n=10)
PowInt                  267.6n ±  0%   251.2n ±  0%   -6.11% (p=0.000 n=10)
PowFrac                 672.9n ±  0%   637.9n ±  0%   -5.19% (p=0.000 n=10)
Pow10Pos                13.87n ±  0%   13.87n ±  0%        ~ (p=1.000 n=10)
Pow10Neg                19.58n ± 62%   19.59n ± 62%        ~ (p=0.355 n=10)
Round                   23.65n ±  0%   23.65n ±  0%        ~ (p=1.000 n=10)
RoundToEven             27.73n ±  0%   27.73n ±  0%        ~ (p=0.635 n=10)
Remainder               309.9n ±  0%   280.5n ±  0%   -9.49% (p=0.000 n=10)
Signbit                 13.05n ±  0%   13.05n ±  0%        ~ (p=1.000 n=10) ¹
Sin                     120.7n ±  0%   120.7n ±  0%        ~ (p=1.000 n=10) ¹
Sincos                  148.4n ±  0%   143.5n ±  0%   -3.30% (p=0.000 n=10)
Sinh                    275.6n ±  0%   267.5n ±  0%   -2.94% (p=0.000 n=10)
SqrtIndirect            3.262n ±  0%   3.262n ±  0%        ~ (p=0.263 n=10)
SqrtLatency             19.57n ±  0%   19.57n ±  0%        ~ (p=0.582 n=10)
SqrtIndirectLatency     19.57n ±  0%   19.57n ±  0%        ~ (p=1.000 n=10)
SqrtGoLatency           203.2n ±  0%   197.6n ±  0%   -2.78% (p=0.000 n=10)
SqrtPrime               4.952µ ±  0%   4.952µ ±  0%   -0.01% (p=0.025 n=10)
Tan                     153.3n ±  0%   153.3n ±  0%        ~ (p=1.000 n=10)
Tanh                    280.5n ±  0%   272.4n ±  0%   -2.91% (p=0.000 n=10)
Trunc                   31.81n ±  0%   31.81n ±  0%        ~ (p=1.000 n=10)
Y0                      680.1n ±  0%   664.8n ±  0%   -2.25% (p=0.000 n=10)
Y1                      684.2n ±  0%   669.6n ±  0%   -2.14% (p=0.000 n=10)
Yn                      1.444µ ±  0%   1.410µ ±  0%   -2.35% (p=0.000 n=10)
Float64bits             5.709n ±  0%   5.708n ±  0%        ~ (p=0.573 n=10)
Float64frombits         4.893n ±  0%   4.893n ±  0%        ~ (p=0.734 n=10)
Float32bits             12.23n ±  0%   12.23n ±  0%        ~ (p=0.628 n=10)
Float32frombits         4.893n ±  0%   4.893n ±  0%        ~ (p=0.971 n=10)
FMA                     4.893n ±  0%   4.893n ±  0%        ~ (p=0.736 n=10)
geomean                 88.96n         87.05n         -2.15%
¹ all samples are equal

Change-Id: I8db8ac7b7b3430b946b89e88dd6c1546804125c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/697360
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Reviewed-by: Cherry Mui 
Reviewed-by: Keith Randall 
Auto-Submit: Michael Munday 
---
 .../compile/internal/ssa/_gen/generic.rules   |  16 +
 src/cmd/compile/internal/ssa/fuse.go          |  10 +-
 .../compile/internal/ssa/fuse_comparisons.go  | 116 +++-
 .../compile/internal/ssa/rewritegeneric.go    | 553 ++++++++++++++++++
 src/cmd/compile/internal/test/float_test.go   | 104 ++++
 test/codegen/fuse.go                          |  80 +++
 6 files changed, 855 insertions(+), 24 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules
index 6fdea7cc7a3cdc..048d9958dc7440 100644
--- a/src/cmd/compile/internal/ssa/_gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/_gen/generic.rules
@@ -347,6 +347,22 @@
 (OrB ((Less|Leq)16U (Const16 [c]) x) (Leq16U x (Const16 [d]))) && uint16(c) >= uint16(d+1) && uint16(d+1) > uint16(d) => ((Less|Leq)16U (Const16  [c-d-1]) (Sub16  x (Const16  [d+1])))
 (OrB ((Less|Leq)8U  (Const8  [c]) x) (Leq8U  x (Const8  [d]))) && uint8(c)  >= uint8(d+1)  && uint8(d+1)  > uint8(d)  => ((Less|Leq)8U  (Const8   [c-d-1]) (Sub8   x (Const8   [d+1])))
 
+// NaN check: ( x != x || x (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) x) )
+(OrB (Neq64F x x) ((Less|Leq)64F x y:(Const64F [c]))) => (Not ((Leq|Less)64F y x))
+(OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) x)) => (Not ((Leq|Less)64F x y))
+(OrB (Neq32F x x) ((Less|Leq)32F x y:(Const32F [c]))) => (Not ((Leq|Less)32F y x))
+(OrB (Neq32F x x) ((Less|Leq)32F y:(Const32F [c]) x)) => (Not ((Leq|Less)32F x y))
+
+// NaN check: ( x != x || Abs(x) (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) Abs(x) )
+(OrB (Neq64F x x) ((Less|Leq)64F abs:(Abs x) y:(Const64F [c]))) => (Not ((Leq|Less)64F y abs))
+(OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) abs:(Abs x))) => (Not ((Leq|Less)64F abs y))
+
+// NaN check: ( x != x || -x (>|>=|<|<=) c ) -> ( !(c (>=|>|<=|<) -x) )
+(OrB (Neq64F x x) ((Less|Leq)64F neg:(Neg64F x) y:(Const64F [c]))) => (Not ((Leq|Less)64F y neg))
+(OrB (Neq64F x x) ((Less|Leq)64F y:(Const64F [c]) neg:(Neg64F x))) => (Not ((Leq|Less)64F neg y))
+(OrB (Neq32F x x) ((Less|Leq)32F neg:(Neg32F x) y:(Const32F [c]))) => (Not ((Leq|Less)32F y neg))
+(OrB (Neq32F x x) ((Less|Leq)32F y:(Const32F [c]) neg:(Neg32F x))) => (Not ((Leq|Less)32F neg y))
+
 // Canonicalize x-const to x+(-const)
 (Sub64 x (Const64  [c])) && x.Op != OpConst64 => (Add64 (Const64  [-c]) x)
 (Sub32 x (Const32  [c])) && x.Op != OpConst32 => (Add32 (Const32  [-c]) x)
diff --git a/src/cmd/compile/internal/ssa/fuse.go b/src/cmd/compile/internal/ssa/fuse.go
index 68defde7b4b956..0cee91b532b101 100644
--- a/src/cmd/compile/internal/ssa/fuse.go
+++ b/src/cmd/compile/internal/ssa/fuse.go
@@ -9,8 +9,8 @@ import (
 	"fmt"
 )
 
-// fuseEarly runs fuse(f, fuseTypePlain|fuseTypeIntInRange).
-func fuseEarly(f *Func) { fuse(f, fuseTypePlain|fuseTypeIntInRange) }
+// fuseEarly runs fuse(f, fuseTypePlain|fuseTypeIntInRange|fuseTypeNanCheck).
+func fuseEarly(f *Func) { fuse(f, fuseTypePlain|fuseTypeIntInRange|fuseTypeNanCheck) }
 
 // fuseLate runs fuse(f, fuseTypePlain|fuseTypeIf|fuseTypeBranchRedirect).
 func fuseLate(f *Func) { fuse(f, fuseTypePlain|fuseTypeIf|fuseTypeBranchRedirect) }
@@ -21,6 +21,7 @@ const (
 	fuseTypePlain fuseType = 1 << iota
 	fuseTypeIf
 	fuseTypeIntInRange
+	fuseTypeNanCheck
 	fuseTypeBranchRedirect
 	fuseTypeShortCircuit
 )
@@ -38,7 +39,10 @@ func fuse(f *Func, typ fuseType) {
 				changed = fuseBlockIf(b) || changed
 			}
 			if typ&fuseTypeIntInRange != 0 {
-				changed = fuseIntegerComparisons(b) || changed
+				changed = fuseIntInRange(b) || changed
+			}
+			if typ&fuseTypeNanCheck != 0 {
+				changed = fuseNanCheck(b) || changed
 			}
 			if typ&fuseTypePlain != 0 {
 				changed = fuseBlockPlain(b) || changed
diff --git a/src/cmd/compile/internal/ssa/fuse_comparisons.go b/src/cmd/compile/internal/ssa/fuse_comparisons.go
index f5fb84b0d73532..b6eb8fcb90dfbc 100644
--- a/src/cmd/compile/internal/ssa/fuse_comparisons.go
+++ b/src/cmd/compile/internal/ssa/fuse_comparisons.go
@@ -4,21 +4,36 @@
 
 package ssa
 
-// fuseIntegerComparisons optimizes inequalities such as '1 <= x && x < 5',
-// which can be optimized to 'unsigned(x-1) < 4'.
-//
-// Look for branch structure like:
+// fuseIntInRange transforms integer range checks to remove the short-circuit operator. For example,
+// it would convert `if 1 <= x && x < 5 { ... }` into `if (1 <= x) & (x < 5) { ... }`. Rewrite rules
+// can then optimize these into unsigned range checks, `if unsigned(x-1) < 4 { ... }` in this case.
+func fuseIntInRange(b *Block) bool {
+	return fuseComparisons(b, canOptIntInRange)
+}
+
+// fuseNanCheck replaces the short-circuit operators between NaN checks and comparisons with
+// constants. For example, it would transform `if x != x || x > 1.0 { ... }` into
+// `if (x != x) | (x > 1.0) { ... }`. Rewrite rules can then merge the NaN check with the comparison,
+// in this case generating `if !(x <= 1.0) { ... }`.
+func fuseNanCheck(b *Block) bool {
+	return fuseComparisons(b, canOptNanCheck)
+}
+
+// fuseComparisons looks for control graphs that match this pattern:
 //
-//	p
+//	p - predecessor
 //	|\
-//	| b
+//	| b - block
 //	|/ \
-//	s0 s1
+//	s0 s1 - successors
 //
-// In our example, p has control '1 <= x', b has control 'x < 5',
-// and s0 and s1 are the if and else results of the comparison.
+// This pattern is typical for if statements such as `if x || y { ... }` and `if x && y { ... }`.
 //
-// This will be optimized into:
+// If canOptControls returns true when passed the control values for p and b then fuseComparisons
+// will try to convert p into a plain block with only one successor (b) and modify b's control
+// value to include p's control value (effectively causing b to be speculatively executed).
+//
+// This transformation results in a control graph that will now look like this:
 //
 //	p
 //	 \
@@ -26,9 +41,12 @@ package ssa
 //	 / \
 //	s0 s1
 //
-// where b has the combined control value 'unsigned(x-1) < 4'.
 // Later passes will then fuse p and b.
-func fuseIntegerComparisons(b *Block) bool {
+//
+// In other words `if x || y { ... }` will become `if x | y { ... }` and `if x && y { ... }` will
+// become `if x & y { ... }`. This is a useful transformation because we can then use rewrite
+// rules to optimize `x | y` and `x & y`.
+func fuseComparisons(b *Block, canOptControls func(a, b *Value, op Op) bool) bool {
 	if len(b.Preds) != 1 {
 		return false
 	}
@@ -45,14 +63,6 @@ func fuseIntegerComparisons(b *Block) bool {
 		return false
 	}
 
-	// Check if the control values combine to make an integer inequality that
-	// can be further optimized later.
-	bc := b.Controls[0]
-	pc := p.Controls[0]
-	if !areMergeableInequalities(bc, pc) {
-		return false
-	}
-
 	// If the first (true) successors match then we have a disjunction (||).
 	// If the second (false) successors match then we have a conjunction (&&).
 	for i, op := range [2]Op{OpOrB, OpAndB} {
@@ -60,6 +70,13 @@ func fuseIntegerComparisons(b *Block) bool {
 			continue
 		}
 
+		// Check if the control values can be usefully combined.
+		bc := b.Controls[0]
+		pc := p.Controls[0]
+		if !canOptControls(bc, pc, op) {
+			return false
+		}
+
 		// TODO(mundaym): should we also check the cost of executing b?
 		// Currently we might speculatively execute b even if b contains
 		// a lot of instructions. We could just check that len(b.Values)
@@ -125,7 +142,7 @@ func isUnsignedInequality(v *Value) bool {
 	return false
 }
 
-func areMergeableInequalities(x, y *Value) bool {
+func canOptIntInRange(x, y *Value, op Op) bool {
 	// We need both inequalities to be either in the signed or unsigned domain.
 	// TODO(mundaym): it would also be good to merge when we have an Eq op that
 	// could be transformed into a Less/Leq. For example in the unsigned
@@ -155,3 +172,60 @@ func areMergeableInequalities(x, y *Value) bool {
 	}
 	return false
 }
+
+// canOptNanCheck reports whether one of arguments is a NaN check and the other
+// is a comparison with a constant that can be combined together.
+//
+// Examples (c must be a constant):
+//
+//	v != v || v <  c => !(c <= v)
+//	v != v || v <= c => !(c <  v)
+//	v != v || c <  v => !(v <= c)
+//	v != v || c <= v => !(v <  c)
+func canOptNanCheck(x, y *Value, op Op) bool {
+	if op != OpOrB {
+		return false
+	}
+
+	for i := 0; i <= 1; i, x, y = i+1, y, x {
+		if len(x.Args) != 2 || x.Args[0] != x.Args[1] {
+			continue
+		}
+		v := x.Args[0]
+		switch x.Op {
+		case OpNeq64F:
+			if y.Op != OpLess64F && y.Op != OpLeq64F {
+				return false
+			}
+			for j := 0; j <= 1; j++ {
+				a, b := y.Args[j], y.Args[j^1]
+				if a.Op != OpConst64F {
+					continue
+				}
+				// Sign bit operations not affect NaN check results. This special case allows us
+				// to optimize statements like `if v != v || Abs(v) > c { ... }`.
+				if (b.Op == OpAbs || b.Op == OpNeg64F) && b.Args[0] == v {
+					return true
+				}
+				return b == v
+			}
+		case OpNeq32F:
+			if y.Op != OpLess32F && y.Op != OpLeq32F {
+				return false
+			}
+			for j := 0; j <= 1; j++ {
+				a, b := y.Args[j], y.Args[j^1]
+				if a.Op != OpConst32F {
+					continue
+				}
+				// Sign bit operations not affect NaN check results. This special case allows us
+				// to optimize statements like `if v != v || -v > c { ... }`.
+				if b.Op == OpNeg32F && b.Args[0] == v {
+					return true
+				}
+				return b == v
+			}
+		}
+	}
+	return false
+}
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 5720063f34b267..37ba324d86cec3 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -23957,6 +23957,7 @@ func rewriteValuegeneric_OpOrB(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
 	b := v.Block
+	typ := &b.Func.Config.Types
 	// match: (OrB (Less64 (Const64 [c]) x) (Less64 x (Const64 [d])))
 	// cond: c >= d
 	// result: (Less64U (Const64  [c-d]) (Sub64  x (Const64  [d])))
@@ -25269,6 +25270,558 @@ func rewriteValuegeneric_OpOrB(v *Value) bool {
 		}
 		break
 	}
+	// match: (OrB (Neq64F x x) (Less64F x y:(Const64F [c])))
+	// result: (Not (Leq64F y x))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst64F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq64F, typ.Bool)
+			v0.AddArg2(y, x)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Leq64F x y:(Const64F [c])))
+	// result: (Not (Less64F y x))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst64F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess64F, typ.Bool)
+			v0.AddArg2(y, x)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Less64F y:(Const64F [c]) x))
+	// result: (Not (Leq64F x y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst64F {
+				continue
+			}
+			if x != v_1.Args[1] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq64F, typ.Bool)
+			v0.AddArg2(x, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Leq64F y:(Const64F [c]) x))
+	// result: (Not (Less64F x y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst64F {
+				continue
+			}
+			if x != v_1.Args[1] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess64F, typ.Bool)
+			v0.AddArg2(x, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq32F x x) (Less32F x y:(Const32F [c])))
+	// result: (Not (Leq32F y x))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq32F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess32F {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst32F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq32F, typ.Bool)
+			v0.AddArg2(y, x)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq32F x x) (Leq32F x y:(Const32F [c])))
+	// result: (Not (Less32F y x))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq32F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq32F {
+				continue
+			}
+			_ = v_1.Args[1]
+			if x != v_1.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst32F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess32F, typ.Bool)
+			v0.AddArg2(y, x)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq32F x x) (Less32F y:(Const32F [c]) x))
+	// result: (Not (Leq32F x y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq32F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess32F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst32F {
+				continue
+			}
+			if x != v_1.Args[1] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq32F, typ.Bool)
+			v0.AddArg2(x, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq32F x x) (Leq32F y:(Const32F [c]) x))
+	// result: (Not (Less32F x y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq32F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq32F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst32F {
+				continue
+			}
+			if x != v_1.Args[1] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess32F, typ.Bool)
+			v0.AddArg2(x, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Less64F abs:(Abs x) y:(Const64F [c])))
+	// result: (Not (Leq64F y abs))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			abs := v_1.Args[0]
+			if abs.Op != OpAbs || x != abs.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst64F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq64F, typ.Bool)
+			v0.AddArg2(y, abs)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Leq64F abs:(Abs x) y:(Const64F [c])))
+	// result: (Not (Less64F y abs))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			abs := v_1.Args[0]
+			if abs.Op != OpAbs || x != abs.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst64F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess64F, typ.Bool)
+			v0.AddArg2(y, abs)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Less64F y:(Const64F [c]) abs:(Abs x)))
+	// result: (Not (Leq64F abs y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst64F {
+				continue
+			}
+			abs := v_1.Args[1]
+			if abs.Op != OpAbs || x != abs.Args[0] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq64F, typ.Bool)
+			v0.AddArg2(abs, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Leq64F y:(Const64F [c]) abs:(Abs x)))
+	// result: (Not (Less64F abs y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst64F {
+				continue
+			}
+			abs := v_1.Args[1]
+			if abs.Op != OpAbs || x != abs.Args[0] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess64F, typ.Bool)
+			v0.AddArg2(abs, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Less64F neg:(Neg64F x) y:(Const64F [c])))
+	// result: (Not (Leq64F y neg))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			neg := v_1.Args[0]
+			if neg.Op != OpNeg64F || x != neg.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst64F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq64F, typ.Bool)
+			v0.AddArg2(y, neg)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Leq64F neg:(Neg64F x) y:(Const64F [c])))
+	// result: (Not (Less64F y neg))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			neg := v_1.Args[0]
+			if neg.Op != OpNeg64F || x != neg.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst64F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess64F, typ.Bool)
+			v0.AddArg2(y, neg)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Less64F y:(Const64F [c]) neg:(Neg64F x)))
+	// result: (Not (Leq64F neg y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst64F {
+				continue
+			}
+			neg := v_1.Args[1]
+			if neg.Op != OpNeg64F || x != neg.Args[0] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq64F, typ.Bool)
+			v0.AddArg2(neg, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq64F x x) (Leq64F y:(Const64F [c]) neg:(Neg64F x)))
+	// result: (Not (Less64F neg y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq64F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq64F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst64F {
+				continue
+			}
+			neg := v_1.Args[1]
+			if neg.Op != OpNeg64F || x != neg.Args[0] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess64F, typ.Bool)
+			v0.AddArg2(neg, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq32F x x) (Less32F neg:(Neg32F x) y:(Const32F [c])))
+	// result: (Not (Leq32F y neg))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq32F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess32F {
+				continue
+			}
+			_ = v_1.Args[1]
+			neg := v_1.Args[0]
+			if neg.Op != OpNeg32F || x != neg.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst32F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq32F, typ.Bool)
+			v0.AddArg2(y, neg)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq32F x x) (Leq32F neg:(Neg32F x) y:(Const32F [c])))
+	// result: (Not (Less32F y neg))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq32F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq32F {
+				continue
+			}
+			_ = v_1.Args[1]
+			neg := v_1.Args[0]
+			if neg.Op != OpNeg32F || x != neg.Args[0] {
+				continue
+			}
+			y := v_1.Args[1]
+			if y.Op != OpConst32F {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess32F, typ.Bool)
+			v0.AddArg2(y, neg)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq32F x x) (Less32F y:(Const32F [c]) neg:(Neg32F x)))
+	// result: (Not (Leq32F neg y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq32F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLess32F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst32F {
+				continue
+			}
+			neg := v_1.Args[1]
+			if neg.Op != OpNeg32F || x != neg.Args[0] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLeq32F, typ.Bool)
+			v0.AddArg2(neg, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
+	// match: (OrB (Neq32F x x) (Leq32F y:(Const32F [c]) neg:(Neg32F x)))
+	// result: (Not (Less32F neg y))
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			if v_0.Op != OpNeq32F {
+				continue
+			}
+			x := v_0.Args[1]
+			if x != v_0.Args[0] || v_1.Op != OpLeq32F {
+				continue
+			}
+			_ = v_1.Args[1]
+			y := v_1.Args[0]
+			if y.Op != OpConst32F {
+				continue
+			}
+			neg := v_1.Args[1]
+			if neg.Op != OpNeg32F || x != neg.Args[0] {
+				continue
+			}
+			v.reset(OpNot)
+			v0 := b.NewValue0(v.Pos, OpLess32F, typ.Bool)
+			v0.AddArg2(neg, y)
+			v.AddArg(v0)
+			return true
+		}
+		break
+	}
 	return false
 }
 func rewriteValuegeneric_OpPhi(v *Value) bool {
diff --git a/src/cmd/compile/internal/test/float_test.go b/src/cmd/compile/internal/test/float_test.go
index 9e61148c5297e5..7a5e27870f97f0 100644
--- a/src/cmd/compile/internal/test/float_test.go
+++ b/src/cmd/compile/internal/test/float_test.go
@@ -623,6 +623,110 @@ func TestInf(t *testing.T) {
 	}
 }
 
+//go:noinline
+func isNaNOrGtZero64(x float64) bool {
+	return math.IsNaN(x) || x > 0
+}
+
+//go:noinline
+func isNaNOrGteZero64(x float64) bool {
+	return x >= 0 || math.IsNaN(x)
+}
+
+//go:noinline
+func isNaNOrLtZero64(x float64) bool {
+	return x < 0 || math.IsNaN(x)
+}
+
+//go:noinline
+func isNaNOrLteZero64(x float64) bool {
+	return math.IsNaN(x) || x <= 0
+}
+
+func TestFusedNaNChecks64(t *testing.T) {
+	tests := []struct {
+		value             float64
+		isZero            bool
+		isGreaterThanZero bool
+		isLessThanZero    bool
+		isNaN             bool
+	}{
+		{value: 0.0, isZero: true},
+		{value: math.Copysign(0, -1), isZero: true},
+		{value: 1.0, isGreaterThanZero: true},
+		{value: -1.0, isLessThanZero: true},
+		{value: math.Inf(1), isGreaterThanZero: true},
+		{value: math.Inf(-1), isLessThanZero: true},
+		{value: math.NaN(), isNaN: true},
+	}
+
+	check := func(name string, f func(x float64) bool, value float64, want bool) {
+		got := f(value)
+		if got != want {
+			t.Errorf("%v(%g): want %v, got %v", name, value, want, got)
+		}
+	}
+
+	for _, test := range tests {
+		check("isNaNOrGtZero64", isNaNOrGtZero64, test.value, test.isNaN || test.isGreaterThanZero)
+		check("isNaNOrGteZero64", isNaNOrGteZero64, test.value, test.isNaN || test.isGreaterThanZero || test.isZero)
+		check("isNaNOrLtZero64", isNaNOrLtZero64, test.value, test.isNaN || test.isLessThanZero)
+		check("isNaNOrLteZero64", isNaNOrLteZero64, test.value, test.isNaN || test.isLessThanZero || test.isZero)
+	}
+}
+
+//go:noinline
+func isNaNOrGtZero32(x float32) bool {
+	return x > 0 || x != x
+}
+
+//go:noinline
+func isNaNOrGteZero32(x float32) bool {
+	return x != x || x >= 0
+}
+
+//go:noinline
+func isNaNOrLtZero32(x float32) bool {
+	return x != x || x < 0
+}
+
+//go:noinline
+func isNaNOrLteZero32(x float32) bool {
+	return x <= 0 || x != x
+}
+
+func TestFusedNaNChecks32(t *testing.T) {
+	tests := []struct {
+		value             float32
+		isZero            bool
+		isGreaterThanZero bool
+		isLessThanZero    bool
+		isNaN             bool
+	}{
+		{value: 0.0, isZero: true},
+		{value: float32(math.Copysign(0, -1)), isZero: true},
+		{value: 1.0, isGreaterThanZero: true},
+		{value: -1.0, isLessThanZero: true},
+		{value: float32(math.Inf(1)), isGreaterThanZero: true},
+		{value: float32(math.Inf(-1)), isLessThanZero: true},
+		{value: float32(math.NaN()), isNaN: true},
+	}
+
+	check := func(name string, f func(x float32) bool, value float32, want bool) {
+		got := f(value)
+		if got != want {
+			t.Errorf("%v(%g): want %v, got %v", name, value, want, got)
+		}
+	}
+
+	for _, test := range tests {
+		check("isNaNOrGtZero32", isNaNOrGtZero32, test.value, test.isNaN || test.isGreaterThanZero)
+		check("isNaNOrGteZero32", isNaNOrGteZero32, test.value, test.isNaN || test.isGreaterThanZero || test.isZero)
+		check("isNaNOrLtZero32", isNaNOrLtZero32, test.value, test.isNaN || test.isLessThanZero)
+		check("isNaNOrLteZero32", isNaNOrLteZero32, test.value, test.isNaN || test.isLessThanZero || test.isZero)
+	}
+}
+
 var sinkFloat float64
 
 func BenchmarkMul2(b *testing.B) {
diff --git a/test/codegen/fuse.go b/test/codegen/fuse.go
index 8d6ea3c5c74664..561bac7224728a 100644
--- a/test/codegen/fuse.go
+++ b/test/codegen/fuse.go
@@ -6,6 +6,8 @@
 
 package codegen
 
+import "math"
+
 // Notes:
 // - these examples use channels to provide a source of
 //   unknown values that cannot be optimized away
@@ -196,6 +198,84 @@ func ui4d(c <-chan uint8) {
 	}
 }
 
+// -------------------------------------//
+// merge NaN checks                     //
+// ------------------------------------ //
+
+func f64NaNOrPosInf(c <-chan float64) {
+	// This test assumes IsInf(x, 1) is implemented as x > MaxFloat rather than x == Inf(1).
+
+	// amd64:"JCS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FCLASSD",-"FLED",-"FLTD",-"FNED",-"FEQD"
+	for x := <-c; math.IsNaN(x) || math.IsInf(x, 1); x = <-c {
+	}
+}
+
+func f64NaNOrNegInf(c <-chan float64) {
+	// This test assumes IsInf(x, -1) is implemented as x < -MaxFloat rather than x == Inf(-1).
+
+	// amd64:"JCS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FCLASSD",-"FLED",-"FLTD",-"FNED",-"FEQD"
+	for x := <-c; math.IsNaN(x) || math.IsInf(x, -1); x = <-c {
+	}
+}
+
+func f64NaNOrLtOne(c <-chan float64) {
+	// amd64:"JCS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FLED",-"FLTD",-"FNED",-"FEQD"
+	for x := <-c; math.IsNaN(x) || x < 1; x = <-c {
+	}
+}
+
+func f64NaNOrLteOne(c <-chan float64) {
+	// amd64:"JLS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FLTD",-"FLED",-"FNED",-"FEQD"
+	for x := <-c; x <= 1 || math.IsNaN(x); x = <-c {
+	}
+}
+
+func f64NaNOrGtOne(c <-chan float64) {
+	// amd64:"JCS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FLED",-"FLTD",-"FNED",-"FEQD"
+	for x := <-c; math.IsNaN(x) || x > 1; x = <-c {
+	}
+}
+
+func f64NaNOrGteOne(c <-chan float64) {
+	// amd64:"JLS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FLTD",-"FLED",-"FNED",-"FEQD"
+	for x := <-c; x >= 1 || math.IsNaN(x); x = <-c {
+	}
+}
+
+func f32NaNOrLtOne(c <-chan float32) {
+	// amd64:"JCS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FLES",-"FLTS",-"FNES",-"FEQS"
+	for x := <-c; x < 1 || x != x; x = <-c {
+	}
+}
+
+func f32NaNOrLteOne(c <-chan float32) {
+	// amd64:"JLS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FLTS",-"FLES",-"FNES",-"FEQS"
+	for x := <-c; x != x || x <= 1; x = <-c {
+	}
+}
+
+func f32NaNOrGtOne(c <-chan float32) {
+	// amd64:"JCS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FLES",-"FLTS",-"FNES",-"FEQS"
+	for x := <-c; x > 1 || x != x; x = <-c {
+	}
+}
+
+func f32NaNOrGteOne(c <-chan float32) {
+	// amd64:"JLS",-"JNE",-"JPS",-"JPC"
+	// riscv64:"FLTS",-"FLES",-"FNES",-"FEQS"
+	for x := <-c; x != x || x >= 1; x = <-c {
+	}
+}
+
 // ------------------------------------ //
 // regressions                          //
 // ------------------------------------ //

From e5d004c7a8777c8333b965266994a8fd2cd45394 Mon Sep 17 00:00:00 2001
From: Damien Neil 
Date: Tue, 7 Oct 2025 11:06:18 -0700
Subject: [PATCH 097/229] net/http: update HTTP/2 documentation to reference
 new config features

Update the package docs to point users at the modern HTTP/2
configuration APIs.

Mention in the TLSNextProto documentation that this field is
superseded by the Protocols field for most user-facing purposes.

Change-Id: I30cd9a85a27e1174338f0d6b887f98c28eac5b5d
Reviewed-on: https://go-review.googlesource.com/c/go/+/709797
Reviewed-by: Nicholas Husin 
Reviewed-by: Nicholas Husin 
Reviewed-by: Brad Fitzpatrick 
LUCI-TryBot-Result: Go LUCI 
---
 src/net/http/doc.go       | 31 +++++++++++++++----------------
 src/net/http/server.go    |  6 +++---
 src/net/http/transport.go |  6 +++---
 3 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/src/net/http/doc.go b/src/net/http/doc.go
index f7ad3ae762fb6c..24e07352ca726d 100644
--- a/src/net/http/doc.go
+++ b/src/net/http/doc.go
@@ -84,27 +84,26 @@ custom Server:
 
 # HTTP/2
 
-Starting with Go 1.6, the http package has transparent support for the
-HTTP/2 protocol when using HTTPS. Programs that must disable HTTP/2
-can do so by setting [Transport.TLSNextProto] (for clients) or
-[Server.TLSNextProto] (for servers) to a non-nil, empty
-map. Alternatively, the following GODEBUG settings are
-currently supported:
+The http package has transparent support for the HTTP/2 protocol.
+
+[Server] and [DefaultTransport] automatically enable HTTP/2 support
+when using HTTPS. [Transport] does not enable HTTP/2 by default.
+
+To enable or disable support for HTTP/1, HTTP/2, and/or unencrypted HTTP/2,
+see the [Server.Protocols] and [Transport.Protocols] configuration fields.
+
+To configure advanced HTTP/2 features, see the [Server.HTTP2] and
+[Transport.HTTP2] configuration fields.
+
+Alternatively, the following GODEBUG settings are currently supported:
 
 	GODEBUG=http2client=0  # disable HTTP/2 client support
 	GODEBUG=http2server=0  # disable HTTP/2 server support
 	GODEBUG=http2debug=1   # enable verbose HTTP/2 debug logs
 	GODEBUG=http2debug=2   # ... even more verbose, with frame dumps
 
-Please report any issues before disabling HTTP/2 support: https://golang.org/s/http2bug
-
-The http package's [Transport] and [Server] both automatically enable
-HTTP/2 support for simple configurations. To enable HTTP/2 for more
-complex configurations, to use lower-level HTTP/2 features, or to use
-a newer version of Go's http2 package, import "golang.org/x/net/http2"
-directly and use its ConfigureTransport and/or ConfigureServer
-functions. Manually configuring HTTP/2 via the golang.org/x/net/http2
-package takes precedence over the net/http package's built-in HTTP/2
-support.
+The "omithttp2" build tag may be used to disable the HTTP/2 implementation
+contained in the http package.
 */
+
 package http
diff --git a/src/net/http/server.go b/src/net/http/server.go
index 4078c899061409..02554d1a201afd 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -3066,6 +3066,9 @@ type Server struct {
 	// automatically closed when the function returns.
 	// If TLSNextProto is not nil, HTTP/2 support is not enabled
 	// automatically.
+	//
+	// Historically, TLSNextProto was used to disable HTTP/2 support.
+	// The Server.Protocols field now provides a simpler way to do this.
 	TLSNextProto map[string]func(*Server, *tls.Conn, Handler)
 
 	// ConnState specifies an optional callback function that is
@@ -3094,9 +3097,6 @@ type Server struct {
 	ConnContext func(ctx context.Context, c net.Conn) context.Context
 
 	// HTTP2 configures HTTP/2 connections.
-	//
-	// This field does not yet have any effect.
-	// See https://go.dev/issue/67813.
 	HTTP2 *HTTP2Config
 
 	// Protocols is the set of protocols accepted by the server.
diff --git a/src/net/http/transport.go b/src/net/http/transport.go
index 5cef9be487a4e2..a560765d331d65 100644
--- a/src/net/http/transport.go
+++ b/src/net/http/transport.go
@@ -249,6 +249,9 @@ type Transport struct {
 	// must return a RoundTripper that then handles the request.
 	// If TLSNextProto is not nil, HTTP/2 support is not enabled
 	// automatically.
+	//
+	// Historically, TLSNextProto was used to disable HTTP/2 support.
+	// The Transport.Protocols field now provides a simpler way to do this.
 	TLSNextProto map[string]func(authority string, c *tls.Conn) RoundTripper
 
 	// ProxyConnectHeader optionally specifies headers to send to
@@ -296,9 +299,6 @@ type Transport struct {
 	ForceAttemptHTTP2 bool
 
 	// HTTP2 configures HTTP/2 connections.
-	//
-	// This field does not yet have any effect.
-	// See https://go.dev/issue/67813.
 	HTTP2 *HTTP2Config
 
 	// Protocols is the set of protocols supported by the transport.

From e1ca1de1234aa0f6be85c97db5492a94b099a305 Mon Sep 17 00:00:00 2001
From: Vlad Saioc 
Date: Mon, 6 Oct 2025 15:10:52 +0000
Subject: [PATCH 098/229] net/http: format pprof.go

Properly formatted net/http/pprof.go to correct
inconsistent whitespaces between keys and values
for profileSupportsDelta.

Change-Id: Iea1515b4289de95862d7eb3af5b8d8d13df2b990
GitHub-Last-Rev: 381d2d3ee746fafdf688b96c8b56a081a1283381
GitHub-Pull-Request: golang/go#75769
Reviewed-on: https://go-review.googlesource.com/c/go/+/709415
Reviewed-by: Dmitri Shuralyov 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Cherry Mui 
Auto-Submit: Dmitri Shuralyov 
---
 src/net/http/pprof/pprof.go | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/net/http/pprof/pprof.go b/src/net/http/pprof/pprof.go
index e5a46ed253cf8b..71aade67d32046 100644
--- a/src/net/http/pprof/pprof.go
+++ b/src/net/http/pprof/pprof.go
@@ -352,13 +352,13 @@ func collectProfile(p *pprof.Profile) (*profile.Profile, error) {
 }
 
 var profileSupportsDelta = map[handler]bool{
-	"allocs":       true,
-	"block":        true,
-	"goroutineleak":        true,
-	"goroutine":    true,
-	"heap":         true,
-	"mutex":        true,
-	"threadcreate": true,
+	"allocs":        true,
+	"block":         true,
+	"goroutineleak": true,
+	"goroutine":     true,
+	"heap":          true,
+	"mutex":         true,
+	"threadcreate":  true,
 }
 
 var profileDescriptions = map[string]string{

From d4830c61301a32ad9373bc30c5fd6196c3567f61 Mon Sep 17 00:00:00 2001
From: Alan Donovan 
Date: Wed, 8 Oct 2025 12:19:14 -0400
Subject: [PATCH 099/229] cmd/internal/obj: fix Link.Diag printf errors

go1.26's vet printf checker can associate the printf-wrapper
property with local vars and struct fields if they are assigned
from a printf-like func literal (CL 706635). This leads to better
detection of mistakes.

Change-Id: I604be1e200aa1aba75e09d4f36ab68c1dba3b8a3
Reviewed-on: https://go-review.googlesource.com/c/go/+/710195
Auto-Submit: Alan Donovan 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Cherry Mui 
---
 src/cmd/internal/obj/arm/asm5.go    | 2 +-
 src/cmd/internal/obj/arm64/asm7.go  | 2 +-
 src/cmd/internal/obj/link.go        | 7 +++++++
 src/cmd/internal/obj/loong64/asm.go | 4 ++--
 src/cmd/internal/obj/mips/asm0.go   | 2 +-
 src/cmd/internal/obj/plist.go       | 4 ++--
 src/cmd/internal/obj/riscv/obj.go   | 2 +-
 7 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/cmd/internal/obj/arm/asm5.go b/src/cmd/internal/obj/arm/asm5.go
index 0ef13b81f6f3f1..1e2891de0a7ddc 100644
--- a/src/cmd/internal/obj/arm/asm5.go
+++ b/src/cmd/internal/obj/arm/asm5.go
@@ -579,7 +579,7 @@ func span5(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 		}
 
 		if int64(pc) > p.Pc {
-			ctxt.Diag("PC padding invalid: want %#d, has %#d: %v", p.Pc, pc, p)
+			ctxt.Diag("PC padding invalid: want %d, has %d: %v", p.Pc, pc, p)
 		}
 		for int64(pc) != p.Pc {
 			// emit 0xe1a00000 (MOVW R0, R0)
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index 743d09a319087d..172c2256d7eede 100644
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -4354,7 +4354,7 @@ func (c *ctxt7) asmout(p *obj.Prog, out []uint32) (count int) {
 		// remove the NOTUSETMP flag in optab.
 		op := c.opirr(p, p.As)
 		if op&Sbit != 0 {
-			c.ctxt.Diag("can not break addition/subtraction when S bit is set", p)
+			c.ctxt.Diag("can not break addition/subtraction when S bit is set (%v)", p)
 		}
 		rt, r := p.To.Reg, p.Reg
 		if r == obj.REG_NONE {
diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index 816fed026f35ad..b7e116bae39dc4 100644
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -1216,6 +1216,13 @@ type Link struct {
 	Fingerprint goobj.FingerprintType // fingerprint of symbol indices, to catch index mismatch
 }
 
+// Assert to vet's printf checker that Link.DiagFunc is a printf-like.
+func _(ctxt *Link) {
+	ctxt.DiagFunc = func(format string, args ...any) {
+		_ = fmt.Sprintf(format, args...)
+	}
+}
+
 func (ctxt *Link) Diag(format string, args ...interface{}) {
 	ctxt.Errors++
 	ctxt.DiagFunc(format, args...)
diff --git a/src/cmd/internal/obj/loong64/asm.go b/src/cmd/internal/obj/loong64/asm.go
index ca6e2be4aa9eb6..ccf093ca9e8d54 100644
--- a/src/cmd/internal/obj/loong64/asm.go
+++ b/src/cmd/internal/obj/loong64/asm.go
@@ -2057,7 +2057,7 @@ func (c *ctxt0) asmout(p *obj.Prog, o *Optab, out []uint32) {
 
 	switch o.type_ {
 	default:
-		c.ctxt.Diag("unknown type %d %v", o.type_)
+		c.ctxt.Diag("unknown type %d", o.type_)
 		prasm(p)
 
 	case 0: // pseudo ops
@@ -4438,7 +4438,7 @@ func (c *ctxt0) specialFpMovInst(a obj.As, fclass int, tclass int) uint32 {
 		}
 	}
 
-	c.ctxt.Diag("bad class combination: %s %s,%s\n", a, fclass, tclass)
+	c.ctxt.Diag("bad class combination: %s %d,%s\n", a, fclass, tclass)
 
 	return 0
 }
diff --git a/src/cmd/internal/obj/mips/asm0.go b/src/cmd/internal/obj/mips/asm0.go
index 2de5a4d6c0b8fc..a55953e741432a 100644
--- a/src/cmd/internal/obj/mips/asm0.go
+++ b/src/cmd/internal/obj/mips/asm0.go
@@ -1172,7 +1172,7 @@ func (c *ctxt0) asmout(p *obj.Prog, o *Optab, out []uint32) {
 	}
 	switch o.type_ {
 	default:
-		c.ctxt.Diag("unknown type %d %v", o.type_)
+		c.ctxt.Diag("unknown type %d", o.type_)
 		prasm(p)
 
 	case 0: /* pseudo ops */
diff --git a/src/cmd/internal/obj/plist.go b/src/cmd/internal/obj/plist.go
index 698e5ace9ccca8..69914b1c1f36d5 100644
--- a/src/cmd/internal/obj/plist.go
+++ b/src/cmd/internal/obj/plist.go
@@ -63,12 +63,12 @@ func Flushplist(ctxt *Link, plist *Plist, newprog ProgAlloc) {
 			switch p.To.Sym.Name {
 			case "go_args_stackmap":
 				if p.From.Type != TYPE_CONST || p.From.Offset != abi.FUNCDATA_ArgsPointerMaps {
-					ctxt.Diag("%s: FUNCDATA use of go_args_stackmap(SB) without FUNCDATA_ArgsPointerMaps", p.Pos)
+					ctxt.Diag("%v: FUNCDATA use of go_args_stackmap(SB) without FUNCDATA_ArgsPointerMaps", p)
 				}
 				p.To.Sym = ctxt.LookupDerived(curtext, curtext.Name+".args_stackmap")
 			case "no_pointers_stackmap":
 				if p.From.Type != TYPE_CONST || p.From.Offset != abi.FUNCDATA_LocalsPointerMaps {
-					ctxt.Diag("%s: FUNCDATA use of no_pointers_stackmap(SB) without FUNCDATA_LocalsPointerMaps", p.Pos)
+					ctxt.Diag("%v: FUNCDATA use of no_pointers_stackmap(SB) without FUNCDATA_LocalsPointerMaps", p)
 				}
 				// funcdata for functions with no local variables in frame.
 				// Define two zero-length bitmaps, because the same index is used
diff --git a/src/cmd/internal/obj/riscv/obj.go b/src/cmd/internal/obj/riscv/obj.go
index 91642ffbcb0e50..4a9c54a3967c4e 100644
--- a/src/cmd/internal/obj/riscv/obj.go
+++ b/src/cmd/internal/obj/riscv/obj.go
@@ -3026,7 +3026,7 @@ func instructionsForOpImmediate(p *obj.Prog, as obj.As, rs int16) []*instruction
 
 	low, high, err := Split32BitImmediate(ins.imm)
 	if err != nil {
-		p.Ctxt.Diag("%v: constant %d too large", p, ins.imm, err)
+		p.Ctxt.Diag("%v: constant %d too large: %v", p, ins.imm, err)
 		return nil
 	}
 	if high == 0 {

From d945600d060e7a0b7c5e72ac606a017d105a17f3 Mon Sep 17 00:00:00 2001
From: Robbie McMichael 
Date: Mon, 6 Oct 2025 12:47:34 +0000
Subject: [PATCH 100/229] cmd/gofmt: change -d to exit 1 if diffs exist

When using the -d flag, set the exit code to 1 if there is a diff.

Fixes #46289

Change-Id: I802e8ccd1798ed7f4448696bec4bc82835ec71a2
GitHub-Last-Rev: db2207fba9a8f7a2f50138ec1f086ac6a74e1b10
GitHub-Pull-Request: golang/go#75649
Reviewed-on: https://go-review.googlesource.com/c/go/+/707635
Reviewed-by: Carlos Amedee 
Reviewed-by: Michael Pratt 
Reviewed-by: Sean Liao 
Auto-Submit: Sean Liao 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/gofmt/gofmt.go                 | 12 +++++-
 src/cmd/gofmt/gofmt_test.go            | 55 ++++++++++++++++++++++++--
 src/cmd/gofmt/testdata/exitcode.golden |  1 +
 src/cmd/gofmt/testdata/exitcode.input  |  1 +
 4 files changed, 64 insertions(+), 5 deletions(-)
 create mode 100644 src/cmd/gofmt/testdata/exitcode.golden
 create mode 100644 src/cmd/gofmt/testdata/exitcode.input

diff --git a/src/cmd/gofmt/gofmt.go b/src/cmd/gofmt/gofmt.go
index bbb8b4fd15c2f7..ad6ad636524479 100644
--- a/src/cmd/gofmt/gofmt.go
+++ b/src/cmd/gofmt/gofmt.go
@@ -41,6 +41,9 @@ var (
 
 	// debugging
 	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to this file")
+
+	// errors
+	errFormattingDiffers = fmt.Errorf("formatting differs from gofmt's")
 )
 
 // Keep these in sync with go/format/format.go.
@@ -218,8 +221,12 @@ func (r *reporter) Report(err error) {
 		panic("Report with nil error")
 	}
 	st := r.getState()
-	scanner.PrintError(st.err, err)
-	st.exitCode = 2
+	if err == errFormattingDiffers {
+		st.exitCode = 1
+	} else {
+		scanner.PrintError(st.err, err)
+		st.exitCode = 2
+	}
 }
 
 func (r *reporter) ExitCode() int {
@@ -281,6 +288,7 @@ func processFile(filename string, info fs.FileInfo, in io.Reader, r *reporter) e
 			newName := filepath.ToSlash(filename)
 			oldName := newName + ".orig"
 			r.Write(diff.Diff(oldName, src, newName, res))
+			return errFormattingDiffers
 		}
 	}
 
diff --git a/src/cmd/gofmt/gofmt_test.go b/src/cmd/gofmt/gofmt_test.go
index 6b80673af148f5..2aba0f03ff09e9 100644
--- a/src/cmd/gofmt/gofmt_test.go
+++ b/src/cmd/gofmt/gofmt_test.go
@@ -53,10 +53,19 @@ func gofmtFlags(filename string, maxLines int) string {
 	return ""
 }
 
-func runTest(t *testing.T, in, out string) {
-	// process flags
-	*simplifyAST = false
+// Reset global variables for all flags to their default value.
+func resetFlags() {
+	*list = false
+	*write = false
 	*rewriteRule = ""
+	*simplifyAST = false
+	*doDiff = false
+	*allErrors = false
+	*cpuprofile = ""
+}
+
+func runTest(t *testing.T, in, out string) {
+	resetFlags()
 	info, err := os.Lstat(in)
 	if err != nil {
 		t.Error(err)
@@ -159,6 +168,46 @@ func TestRewrite(t *testing.T) {
 	}
 }
 
+// TestDiff runs gofmt with the -d flag on the input files and checks that the
+// expected exit code is set.
+func TestDiff(t *testing.T) {
+	tests := []struct {
+		in       string
+		exitCode int
+	}{
+		{in: "testdata/exitcode.input", exitCode: 1},
+		{in: "testdata/exitcode.golden", exitCode: 0},
+	}
+
+	for _, tt := range tests {
+		resetFlags()
+		*doDiff = true
+
+		initParserMode()
+		initRewrite()
+
+		info, err := os.Lstat(tt.in)
+		if err != nil {
+			t.Error(err)
+			return
+		}
+
+		const maxWeight = 2 << 20
+		var buf, errBuf bytes.Buffer
+		s := newSequencer(maxWeight, &buf, &errBuf)
+		s.Add(fileWeight(tt.in, info), func(r *reporter) error {
+			return processFile(tt.in, info, nil, r)
+		})
+		if errBuf.Len() > 0 {
+			t.Logf("%q", errBuf.Bytes())
+		}
+
+		if s.GetExitCode() != tt.exitCode {
+			t.Errorf("%s: expected exit code %d, got %d", tt.in, tt.exitCode, s.GetExitCode())
+		}
+	}
+}
+
 // Test case for issue 3961.
 func TestCRLF(t *testing.T) {
 	const input = "testdata/crlf.input"   // must contain CR/LF's
diff --git a/src/cmd/gofmt/testdata/exitcode.golden b/src/cmd/gofmt/testdata/exitcode.golden
new file mode 100644
index 00000000000000..06ab7d0f9a35a7
--- /dev/null
+++ b/src/cmd/gofmt/testdata/exitcode.golden
@@ -0,0 +1 @@
+package main
diff --git a/src/cmd/gofmt/testdata/exitcode.input b/src/cmd/gofmt/testdata/exitcode.input
new file mode 100644
index 00000000000000..4f2f092ce508de
--- /dev/null
+++ b/src/cmd/gofmt/testdata/exitcode.input
@@ -0,0 +1 @@
+	package main

From 941e5917c113e8414ad8dc5f36c8ebae33497be4 Mon Sep 17 00:00:00 2001
From: Paul Murphy 
Date: Wed, 1 Oct 2025 09:23:18 -0500
Subject: [PATCH 101/229] runtime: cleanup comments from asm_ppc64x.s
 improvements

CL 706395 consolidated the aix and elf startup code, further
update the comments to reflect this.

Change-Id: Iccb98008b3fe4a4b08e55ee822924fad76846cc2
Reviewed-on: https://go-review.googlesource.com/c/go/+/708355
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Paul Murphy 
Reviewed-by: Quim Muntal 
Reviewed-by: Michael Pratt 
Reviewed-by: Keith Randall 
---
 src/runtime/asm_ppc64x.s | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index b42e0b62f850ff..88d03dcc72c1e6 100644
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -11,10 +11,10 @@
 #include "asm_ppc64x.h"
 #include "cgo/abi_ppc64x.h"
 
-
+// This is called using the host ABI. argc and argv arguments
+// should be in R3 and R4 respectively.
 TEXT _rt0_ppc64x_lib(SB),NOSPLIT|NOFRAME,$0
-	// This is called with ELFv2 calling conventions. Convert to Go.
-	// Allocate argument storage for call to newosproc0.
+	// Convert to Go ABI, and Allocate argument storage for call to newosproc0.
 	STACK_AND_SAVE_HOST_TO_GO_ABI(16)
 
 	MOVD	R3, _rt0_ppc64x_lib_argc<>(SB)
@@ -48,7 +48,6 @@ nocgo:
 	BL	(CTR)
 
 done:
-	// Restore and return to ELFv2 caller.
 	UNSTACK_AND_RESTORE_GO_TO_HOST_ABI(16)
 	RET
 

From ae094a1397d03aafde380cdb79e0d6a5731c8dbc Mon Sep 17 00:00:00 2001
From: Filippo Valsorda 
Date: Mon, 29 Sep 2025 13:36:28 +0200
Subject: [PATCH 102/229] crypto/internal/fips140test: make entropy file pair
 names match

Change-Id: I6a6a69642d00e3994277d9b5631d1d7f18f3f356
Reviewed-on: https://go-review.googlesource.com/c/go/+/710055
Reviewed-by: Roland Shoemaker 
Reviewed-by: Daniel McCarney 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Filippo Valsorda 
Reviewed-by: Michael Pratt 
---
 src/crypto/internal/fips140test/entropy_test.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/crypto/internal/fips140test/entropy_test.go b/src/crypto/internal/fips140test/entropy_test.go
index 76c24289520e17..a84b50c62b22b6 100644
--- a/src/crypto/internal/fips140test/entropy_test.go
+++ b/src/crypto/internal/fips140test/entropy_test.go
@@ -31,11 +31,12 @@ var flagNISTSP80090B = flag.Bool("nist-sp800-90b", false, "run NIST SP 800-90B t
 
 func TestEntropySamples(t *testing.T) {
 	cryptotest.MustSupportFIPS140(t)
+	now := time.Now().UTC()
 
 	var seqSamples [1_000_000]uint8
 	samplesOrTryAgain(t, seqSamples[:])
 	seqSamplesName := fmt.Sprintf("entropy_samples_sequential_%s_%s_%s_%s_%s.bin", entropy.Version(),
-		runtime.GOOS, runtime.GOARCH, *flagEntropySamples, time.Now().Format("20060102T150405Z"))
+		runtime.GOOS, runtime.GOARCH, *flagEntropySamples, now.Format("20060102T150405Z"))
 	if *flagEntropySamples != "" {
 		if err := os.WriteFile(seqSamplesName, seqSamples[:], 0644); err != nil {
 			t.Fatalf("failed to write samples to %q: %v", seqSamplesName, err)
@@ -50,7 +51,7 @@ func TestEntropySamples(t *testing.T) {
 		copy(restartSamples[i][:], samples[:])
 	}
 	restartSamplesName := fmt.Sprintf("entropy_samples_restart_%s_%s_%s_%s_%s.bin", entropy.Version(),
-		runtime.GOOS, runtime.GOARCH, *flagEntropySamples, time.Now().Format("20060102T150405Z"))
+		runtime.GOOS, runtime.GOARCH, *flagEntropySamples, now.Format("20060102T150405Z"))
 	if *flagEntropySamples != "" {
 		f, err := os.Create(restartSamplesName)
 		if err != nil {

From de9da0de30377532370a09a311851afc0616c185 Mon Sep 17 00:00:00 2001
From: Mateusz Poliwczak 
Date: Tue, 7 Oct 2025 17:57:59 +0000
Subject: [PATCH 103/229] cmd/compile/internal/devirtualize: improve concrete
 type analysis

This change improves the concrete type analysis in the devirtualizer,
it not longer relies on ir.Reassigned, it now statically tries to
determine the concrete type of an interface, even when assigned
multiple times, following type assertions and iface conversions.

Alternative to CL 649195

Updates #69521
Fixes #64824

Change-Id: Ib1656e19f3619ab2e1e6b2c78346cc320490b2af
GitHub-Last-Rev: e8fa0b12f0a7b1d7ae00e5edb54ce04d1f702c09
GitHub-Pull-Request: golang/go#71935
Reviewed-on: https://go-review.googlesource.com/c/go/+/652036
Reviewed-by: Michael Pratt 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Keith Randall 
---
 .../internal/devirtualize/devirtualize.go     |  463 +++++-
 .../inline/interleaved/interleaved.go         |   37 +-
 src/cmd/compile/internal/ir/expr.go           |    5 +
 src/cmd/compile/internal/noder/reader.go      |    1 +
 src/cmd/compile/internal/ssagen/ssa.go        |   19 +
 src/crypto/sha256/sha256_test.go              |   14 +
 src/runtime/pprof/pprof_test.go               |    5 +
 test/devirtualization.go                      | 1277 +++++++++++++++++
 test/devirtualization_nil_panics.go           |  100 ++
 ...zation_with_type_assertions_interleaved.go |  139 ++
 test/fixedbugs/issue42284.dir/a.go            |    7 +-
 test/fixedbugs/issue42284.dir/b.go            |    7 +-
 12 files changed, 2039 insertions(+), 35 deletions(-)
 create mode 100644 test/devirtualization.go
 create mode 100644 test/devirtualization_nil_panics.go
 create mode 100644 test/devirtualization_with_type_assertions_interleaved.go

diff --git a/src/cmd/compile/internal/devirtualize/devirtualize.go b/src/cmd/compile/internal/devirtualize/devirtualize.go
index 372d05809401ff..9d4160085edde9 100644
--- a/src/cmd/compile/internal/devirtualize/devirtualize.go
+++ b/src/cmd/compile/internal/devirtualize/devirtualize.go
@@ -18,9 +18,11 @@ import (
 	"cmd/compile/internal/types"
 )
 
+const go126ImprovedConcreteTypeAnalysis = true
+
 // StaticCall devirtualizes the given call if possible when the concrete callee
 // is available statically.
-func StaticCall(call *ir.CallExpr) {
+func StaticCall(s *State, call *ir.CallExpr) {
 	// For promoted methods (including value-receiver methods promoted
 	// to pointer-receivers), the interface method wrapper may contain
 	// expressions that can panic (e.g., ODEREF, ODOTPTR,
@@ -40,15 +42,31 @@ func StaticCall(call *ir.CallExpr) {
 	}
 
 	sel := call.Fun.(*ir.SelectorExpr)
-	r := ir.StaticValue(sel.X)
-	if r.Op() != ir.OCONVIFACE {
-		return
-	}
-	recv := r.(*ir.ConvExpr)
+	var typ *types.Type
+	if go126ImprovedConcreteTypeAnalysis {
+		typ = concreteType(s, sel.X)
+		if typ == nil {
+			return
+		}
 
-	typ := recv.X.Type()
-	if typ.IsInterface() {
-		return
+		// Don't create type-assertions that would be impossible at compile-time.
+		// This can happen in such case: any(0).(interface {A()}).A(), this typechecks without
+		// any errors, but will cause a runtime panic. We statically know that int(0) does not
+		// implement that interface, thus we skip the devirtualization, as it is not possible
+		// to make an assertion: any(0).(interface{A()}).(int) (int does not implement interface{A()}).
+		if !typecheck.Implements(typ, sel.X.Type()) {
+			return
+		}
+	} else {
+		r := ir.StaticValue(sel.X)
+		if r.Op() != ir.OCONVIFACE {
+			return
+		}
+		recv := r.(*ir.ConvExpr)
+		typ = recv.X.Type()
+		if typ.IsInterface() {
+			return
+		}
 	}
 
 	// If typ is a shape type, then it was a type argument originally
@@ -99,8 +117,27 @@ func StaticCall(call *ir.CallExpr) {
 		return
 	}
 
-	dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, nil)
-	dt.SetType(typ)
+	dt := ir.NewTypeAssertExpr(sel.Pos(), sel.X, typ)
+
+	if go126ImprovedConcreteTypeAnalysis {
+		// Consider:
+		//
+		//	var v Iface
+		//	v.A()
+		//	v = &Impl{}
+		//
+		// Here in the devirtualizer, we determine the concrete type of v as being an *Impl,
+		// but it can still be a nil interface, we have not detected that. The v.(*Impl)
+		// type assertion that we make here would also have failed, but with a different
+		// panic "pkg.Iface is nil, not *pkg.Impl", where previously we would get a nil panic.
+		// We fix this, by introducing an additional nilcheck on the itab.
+		// Calling a method on an nil interface (in most cases) is a bug in a program, so it is fine
+		// to devirtualize and further (possibly) inline them, even though we would never reach
+		// the called function.
+		dt.UseNilPanic = true
+		dt.SetPos(call.Pos())
+	}
+
 	x := typecheck.XDotMethod(sel.Pos(), dt, sel.Sel, true)
 	switch x.Op() {
 	case ir.ODOTMETH:
@@ -138,3 +175,407 @@ func StaticCall(call *ir.CallExpr) {
 	// Desugar OCALLMETH, if we created one (#57309).
 	typecheck.FixMethodCall(call)
 }
+
+const concreteTypeDebug = false
+
+// concreteType determines the concrete type of n, following OCONVIFACEs and type asserts.
+// Returns nil when the concrete type could not be determined, or when there are multiple
+// (different) types assigned to an interface.
+func concreteType(s *State, n ir.Node) (typ *types.Type) {
+	typ = concreteType1(s, n, make(map[*ir.Name]struct{}))
+	if typ == &noType {
+		return nil
+	}
+	if typ != nil && typ.IsInterface() {
+		base.Fatalf("typ.IsInterface() = true; want = false; typ = %v", typ)
+	}
+	return typ
+}
+
+// noType is a sentinel value returned by [concreteType1].
+var noType types.Type
+
+// concreteType1 analyzes the node n and returns its concrete type if it is statically known.
+// Otherwise, it returns a nil Type, indicating that a concrete type was not determined.
+// When n is known to be statically nil or a self-assignment is detected, in returns a sentinel [noType] type instead.
+func concreteType1(s *State, n ir.Node, seen map[*ir.Name]struct{}) (outT *types.Type) {
+	nn := n // for debug messages
+
+	if concreteTypeDebug {
+		defer func() {
+			t := "&noType"
+			if outT != &noType {
+				t = outT.String()
+			}
+			base.Warn("concreteType1(%v) -> %v", nn, t)
+		}()
+	}
+
+	for {
+		if concreteTypeDebug {
+			base.Warn("concreteType1(%v): analyzing %v", nn, n)
+		}
+
+		if !n.Type().IsInterface() {
+			return n.Type()
+		}
+
+		switch n1 := n.(type) {
+		case *ir.ConvExpr:
+			if n1.Op() == ir.OCONVNOP {
+				if !n1.Type().IsInterface() || !types.Identical(n1.Type(), n1.X.Type()) {
+					// As we check (directly before this switch) whether n is an interface, thus we should only reach
+					// here for iface conversions where both operands are the same.
+					base.Fatalf("not identical/interface types found n1.Type = %v; n1.X.Type = %v", n1.Type(), n1.X.Type())
+				}
+				n = n1.X
+				continue
+			}
+			if n1.Op() == ir.OCONVIFACE {
+				n = n1.X
+				continue
+			}
+		case *ir.InlinedCallExpr:
+			if n1.Op() == ir.OINLCALL {
+				n = n1.SingleResult()
+				continue
+			}
+		case *ir.ParenExpr:
+			n = n1.X
+			continue
+		case *ir.TypeAssertExpr:
+			n = n1.X
+			continue
+		}
+		break
+	}
+
+	if n.Op() != ir.ONAME {
+		return nil
+	}
+
+	name := n.(*ir.Name).Canonical()
+	if name.Class != ir.PAUTO {
+		return nil
+	}
+
+	if name.Op() != ir.ONAME {
+		base.Fatalf("name.Op = %v; want = ONAME", n.Op())
+	}
+
+	// name.Curfn must be set, as we checked name.Class != ir.PAUTO before.
+	if name.Curfn == nil {
+		base.Fatalf("name.Curfn = nil; want not nil")
+	}
+
+	if name.Addrtaken() {
+		return nil // conservatively assume it's reassigned with a different type indirectly
+	}
+
+	if _, ok := seen[name]; ok {
+		return &noType // Already analyzed assignments to name, no need to do that twice.
+	}
+	seen[name] = struct{}{}
+
+	if concreteTypeDebug {
+		base.Warn("concreteType1(%v): analyzing assignments to %v", nn, name)
+	}
+
+	var typ *types.Type
+	for _, v := range s.assignments(name) {
+		var t *types.Type
+		switch v := v.(type) {
+		case *types.Type:
+			t = v
+		case ir.Node:
+			t = concreteType1(s, v, seen)
+			if t == &noType {
+				continue
+			}
+		}
+		if t == nil || (typ != nil && !types.Identical(typ, t)) {
+			return nil
+		}
+		typ = t
+	}
+
+	if typ == nil {
+		// Variable either declared with zero value, or only assigned with nil.
+		return &noType
+	}
+
+	return typ
+}
+
+// assignment can be one of:
+// - nil - assignment from an interface type.
+// - *types.Type - assignment from a concrete type (non-interface).
+// - ir.Node - assignment from a ir.Node.
+//
+// In most cases assignment should be an [ir.Node], but in cases where we
+// do not follow the data-flow, we return either a concrete type (*types.Type) or a nil.
+// For example in range over a slice, if the slice elem is of an interface type, then we return
+// a nil, otherwise the elem's concrete type (We do so because we do not analyze assignment to the
+// slice being ranged-over).
+type assignment any
+
+// State holds precomputed state for use in [StaticCall].
+type State struct {
+	// ifaceAssignments maps interface variables to all their assignments
+	// defined inside functions stored in the analyzedFuncs set.
+	// Note: it does not include direct assignments to nil.
+	ifaceAssignments map[*ir.Name][]assignment
+
+	// ifaceCallExprAssigns stores every [*ir.CallExpr], which has an interface
+	// result, that is assigned to a variable.
+	ifaceCallExprAssigns map[*ir.CallExpr][]ifaceAssignRef
+
+	// analyzedFuncs is a set of Funcs that were analyzed for iface assignments.
+	analyzedFuncs map[*ir.Func]struct{}
+}
+
+type ifaceAssignRef struct {
+	name            *ir.Name // ifaceAssignments[name]
+	assignmentIndex int      // ifaceAssignments[name][assignmentIndex]
+	returnIndex     int      // (*ir.CallExpr).Result(returnIndex)
+}
+
+// InlinedCall updates the [State] to take into account a newly inlined call.
+func (s *State) InlinedCall(fun *ir.Func, origCall *ir.CallExpr, inlinedCall *ir.InlinedCallExpr) {
+	if _, ok := s.analyzedFuncs[fun]; !ok {
+		// Full analyze has not been yet executed for the provided function, so we can skip it for now.
+		// When no devirtualization happens in a function, it is unnecessary to analyze it.
+		return
+	}
+
+	// Analyze assignments in the newly inlined function.
+	s.analyze(inlinedCall.Init())
+	s.analyze(inlinedCall.Body)
+
+	refs, ok := s.ifaceCallExprAssigns[origCall]
+	if !ok {
+		return
+	}
+	delete(s.ifaceCallExprAssigns, origCall)
+
+	// Update assignments to reference the new ReturnVars of the inlined call.
+	for _, ref := range refs {
+		vt := &s.ifaceAssignments[ref.name][ref.assignmentIndex]
+		if *vt != nil {
+			base.Fatalf("unexpected non-nil assignment")
+		}
+		if concreteTypeDebug {
+			base.Warn(
+				"InlinedCall(%v, %v): replacing interface node in (%v,%v) to %v (typ %v)",
+				origCall, inlinedCall, ref.name, ref.assignmentIndex,
+				inlinedCall.ReturnVars[ref.returnIndex],
+				inlinedCall.ReturnVars[ref.returnIndex].Type(),
+			)
+		}
+
+		// Update ifaceAssignments with an ir.Node from the inlined function’s ReturnVars.
+		// This may enable future devirtualization of calls that reference ref.name.
+		// We will get calls to [StaticCall] from the interleaved package,
+		// to try devirtualize such calls afterwards.
+		*vt = inlinedCall.ReturnVars[ref.returnIndex]
+	}
+}
+
+// assignments returns all assignments to n.
+func (s *State) assignments(n *ir.Name) []assignment {
+	fun := n.Curfn
+	if fun == nil {
+		base.Fatalf("n.Curfn = ")
+	}
+
+	if !n.Type().IsInterface() {
+		base.Fatalf("name passed to assignments is not of an interface type: %v", n.Type())
+	}
+
+	// Analyze assignments in func, if not analyzed before.
+	if _, ok := s.analyzedFuncs[fun]; !ok {
+		if concreteTypeDebug {
+			base.Warn("assignments(): analyzing assignments in %v func", fun)
+		}
+		if s.analyzedFuncs == nil {
+			s.ifaceAssignments = make(map[*ir.Name][]assignment)
+			s.ifaceCallExprAssigns = make(map[*ir.CallExpr][]ifaceAssignRef)
+			s.analyzedFuncs = make(map[*ir.Func]struct{})
+		}
+		s.analyzedFuncs[fun] = struct{}{}
+		s.analyze(fun.Init())
+		s.analyze(fun.Body)
+	}
+
+	return s.ifaceAssignments[n]
+}
+
+// analyze analyzes every assignment to interface variables in nodes, updating [State].
+func (s *State) analyze(nodes ir.Nodes) {
+	assign := func(name ir.Node, assignment assignment) (*ir.Name, int) {
+		if name == nil || name.Op() != ir.ONAME || ir.IsBlank(name) {
+			return nil, -1
+		}
+
+		n, ok := ir.OuterValue(name).(*ir.Name)
+		if !ok || n.Curfn == nil {
+			return nil, -1
+		}
+
+		// Do not track variables that are not of interface types.
+		// For devirtualization they are unnecessary, we will not even look them up.
+		if !n.Type().IsInterface() {
+			return nil, -1
+		}
+
+		n = n.Canonical()
+		if n.Op() != ir.ONAME {
+			base.Fatalf("n.Op = %v; want = ONAME", n.Op())
+		}
+
+		switch a := assignment.(type) {
+		case nil:
+		case *types.Type:
+			if a != nil && a.IsInterface() {
+				assignment = nil // non-concrete type
+			}
+		case ir.Node:
+			// nil assignment, we can safely ignore them, see [StaticCall].
+			if ir.IsNil(a) {
+				return nil, -1
+			}
+		default:
+			base.Fatalf("unexpected type: %v", assignment)
+		}
+
+		if concreteTypeDebug {
+			base.Warn("analyze(): assignment found %v = %v", name, assignment)
+		}
+
+		s.ifaceAssignments[n] = append(s.ifaceAssignments[n], assignment)
+		return n, len(s.ifaceAssignments[n]) - 1
+	}
+
+	var do func(n ir.Node)
+	do = func(n ir.Node) {
+		switch n.Op() {
+		case ir.OAS:
+			n := n.(*ir.AssignStmt)
+			if rhs := n.Y; rhs != nil {
+				for {
+					if r, ok := rhs.(*ir.ParenExpr); ok {
+						rhs = r.X
+						continue
+					}
+					break
+				}
+				if call, ok := rhs.(*ir.CallExpr); ok && call.Fun != nil {
+					retTyp := call.Fun.Type().Results()[0].Type
+					n, idx := assign(n.X, retTyp)
+					if n != nil && retTyp.IsInterface() {
+						// We have a call expression, that returns an interface, store it for later evaluation.
+						// In case this func gets inlined later, we will update the assignment (added before)
+						// with a reference to ReturnVars, see [State.InlinedCall], which might allow for future devirtualizing of n.X.
+						s.ifaceCallExprAssigns[call] = append(s.ifaceCallExprAssigns[call], ifaceAssignRef{n, idx, 0})
+					}
+				} else {
+					assign(n.X, rhs)
+				}
+			}
+		case ir.OAS2:
+			n := n.(*ir.AssignListStmt)
+			for i, p := range n.Lhs {
+				if n.Rhs[i] != nil {
+					assign(p, n.Rhs[i])
+				}
+			}
+		case ir.OAS2DOTTYPE:
+			n := n.(*ir.AssignListStmt)
+			if n.Rhs[0] == nil {
+				base.Fatalf("n.Rhs[0] == nil; n = %v", n)
+			}
+			assign(n.Lhs[0], n.Rhs[0])
+			assign(n.Lhs[1], nil) // boolean does not have methods to devirtualize
+		case ir.OAS2MAPR, ir.OAS2RECV, ir.OSELRECV2:
+			n := n.(*ir.AssignListStmt)
+			if n.Rhs[0] == nil {
+				base.Fatalf("n.Rhs[0] == nil; n = %v", n)
+			}
+			assign(n.Lhs[0], n.Rhs[0].Type())
+			assign(n.Lhs[1], nil) // boolean does not have methods to devirtualize
+		case ir.OAS2FUNC:
+			n := n.(*ir.AssignListStmt)
+			rhs := n.Rhs[0]
+			for {
+				if r, ok := rhs.(*ir.ParenExpr); ok {
+					rhs = r.X
+					continue
+				}
+				break
+			}
+			if call, ok := rhs.(*ir.CallExpr); ok {
+				for i, p := range n.Lhs {
+					retTyp := call.Fun.Type().Results()[i].Type
+					n, idx := assign(p, retTyp)
+					if n != nil && retTyp.IsInterface() {
+						// We have a call expression, that returns an interface, store it for later evaluation.
+						// In case this func gets inlined later, we will update the assignment (added before)
+						// with a reference to ReturnVars, see [State.InlinedCall], which might allow for future devirtualizing of n.X.
+						s.ifaceCallExprAssigns[call] = append(s.ifaceCallExprAssigns[call], ifaceAssignRef{n, idx, i})
+					}
+				}
+			} else if call, ok := rhs.(*ir.InlinedCallExpr); ok {
+				for i, p := range n.Lhs {
+					assign(p, call.ReturnVars[i])
+				}
+			} else {
+				base.Fatalf("unexpected type %T in OAS2FUNC Rhs[0]", call)
+			}
+		case ir.ORANGE:
+			n := n.(*ir.RangeStmt)
+			xTyp := n.X.Type()
+
+			// Range over an array pointer.
+			if xTyp.IsPtr() && xTyp.Elem().IsArray() {
+				xTyp = xTyp.Elem()
+			}
+
+			if xTyp.IsArray() || xTyp.IsSlice() {
+				assign(n.Key, nil) // integer does not have methods to devirtualize
+				assign(n.Value, xTyp.Elem())
+			} else if xTyp.IsChan() {
+				assign(n.Key, xTyp.Elem())
+				base.Assertf(n.Value == nil, "n.Value != nil in range over chan")
+			} else if xTyp.IsMap() {
+				assign(n.Key, xTyp.Key())
+				assign(n.Value, xTyp.Elem())
+			} else if xTyp.IsInteger() || xTyp.IsString() {
+				// Range over int/string, results do not have methods, so nothing to devirtualize.
+				assign(n.Key, nil)
+				assign(n.Value, nil)
+			} else {
+				// We will not reach here in case of an range-over-func, as it is
+				// rewrtten to function calls in the noder package.
+				base.Fatalf("range over unexpected type %v", n.X.Type())
+			}
+		case ir.OSWITCH:
+			n := n.(*ir.SwitchStmt)
+			if guard, ok := n.Tag.(*ir.TypeSwitchGuard); ok {
+				for _, v := range n.Cases {
+					if v.Var == nil {
+						base.Assert(guard.Tag == nil)
+						continue
+					}
+					assign(v.Var, guard.X)
+				}
+			}
+		case ir.OCLOSURE:
+			n := n.(*ir.ClosureExpr)
+			if _, ok := s.analyzedFuncs[n.Func]; !ok {
+				s.analyzedFuncs[n.Func] = struct{}{}
+				ir.Visit(n.Func, do)
+			}
+		}
+	}
+	ir.VisitList(nodes, do)
+}
diff --git a/src/cmd/compile/internal/inline/interleaved/interleaved.go b/src/cmd/compile/internal/inline/interleaved/interleaved.go
index 954cc306fc81d3..c83bbdb718df56 100644
--- a/src/cmd/compile/internal/inline/interleaved/interleaved.go
+++ b/src/cmd/compile/internal/inline/interleaved/interleaved.go
@@ -45,6 +45,8 @@ func DevirtualizeAndInlinePackage(pkg *ir.Package, profile *pgoir.Profile) {
 	inlState := make(map[*ir.Func]*inlClosureState)
 	calleeUseCounts := make(map[*ir.Func]int)
 
+	var state devirtualize.State
+
 	// Pre-process all the functions, adding parentheses around call sites and starting their "inl state".
 	for _, fn := range typecheck.Target.Funcs {
 		bigCaller := base.Flag.LowerL != 0 && inline.IsBigFunc(fn)
@@ -58,7 +60,7 @@ func DevirtualizeAndInlinePackage(pkg *ir.Package, profile *pgoir.Profile) {
 
 		// Do a first pass at counting call sites.
 		for i := range s.parens {
-			s.resolve(i)
+			s.resolve(&state, i)
 		}
 	}
 
@@ -102,10 +104,11 @@ func DevirtualizeAndInlinePackage(pkg *ir.Package, profile *pgoir.Profile) {
 					for {
 						for i := l0; i < l1; i++ { // can't use "range parens" here
 							paren := s.parens[i]
-							if new := s.edit(i); new != nil {
+							if origCall, inlinedCall := s.edit(&state, i); inlinedCall != nil {
 								// Update AST and recursively mark nodes.
-								paren.X = new
-								ir.EditChildren(new, s.mark) // mark may append to parens
+								paren.X = inlinedCall
+								ir.EditChildren(inlinedCall, s.mark) // mark may append to parens
+								state.InlinedCall(s.fn, origCall, inlinedCall)
 								done = false
 							}
 						}
@@ -114,7 +117,7 @@ func DevirtualizeAndInlinePackage(pkg *ir.Package, profile *pgoir.Profile) {
 							break
 						}
 						for i := l0; i < l1; i++ {
-							s.resolve(i)
+							s.resolve(&state, i)
 						}
 
 					}
@@ -188,7 +191,7 @@ type inlClosureState struct {
 // resolve attempts to resolve a call to a potentially inlineable callee
 // and updates use counts on the callees.  Returns the call site count
 // for that callee.
-func (s *inlClosureState) resolve(i int) (*ir.Func, int) {
+func (s *inlClosureState) resolve(state *devirtualize.State, i int) (*ir.Func, int) {
 	p := s.parens[i]
 	if i < len(s.resolved) {
 		if callee := s.resolved[i]; callee != nil {
@@ -200,7 +203,7 @@ func (s *inlClosureState) resolve(i int) (*ir.Func, int) {
 	if !ok { // previously inlined
 		return nil, -1
 	}
-	devirtualize.StaticCall(call)
+	devirtualize.StaticCall(state, call)
 	if callee := inline.InlineCallTarget(s.fn, call, s.profile); callee != nil {
 		for len(s.resolved) <= i {
 			s.resolved = append(s.resolved, nil)
@@ -213,23 +216,23 @@ func (s *inlClosureState) resolve(i int) (*ir.Func, int) {
 	return nil, 0
 }
 
-func (s *inlClosureState) edit(i int) ir.Node {
+func (s *inlClosureState) edit(state *devirtualize.State, i int) (*ir.CallExpr, *ir.InlinedCallExpr) {
 	n := s.parens[i].X
 	call, ok := n.(*ir.CallExpr)
 	if !ok {
-		return nil
+		return nil, nil
 	}
 	// This is redundant with earlier calls to
 	// resolve, but because things can change it
 	// must be re-checked.
-	callee, count := s.resolve(i)
+	callee, count := s.resolve(state, i)
 	if count <= 0 {
-		return nil
+		return nil, nil
 	}
 	if inlCall := inline.TryInlineCall(s.fn, call, s.bigCaller, s.profile, count == 1 && callee.ClosureParent != nil); inlCall != nil {
-		return inlCall
+		return call, inlCall
 	}
-	return nil
+	return nil, nil
 }
 
 // Mark inserts parentheses, and is called repeatedly.
@@ -338,16 +341,18 @@ func (s *inlClosureState) unparenthesize() {
 // returns.
 func (s *inlClosureState) fixpoint() bool {
 	changed := false
+	var state devirtualize.State
 	ir.WithFunc(s.fn, func() {
 		done := false
 		for !done {
 			done = true
 			for i := 0; i < len(s.parens); i++ { // can't use "range parens" here
 				paren := s.parens[i]
-				if new := s.edit(i); new != nil {
+				if origCall, inlinedCall := s.edit(&state, i); inlinedCall != nil {
 					// Update AST and recursively mark nodes.
-					paren.X = new
-					ir.EditChildren(new, s.mark) // mark may append to parens
+					paren.X = inlinedCall
+					ir.EditChildren(inlinedCall, s.mark) // mark may append to parens
+					state.InlinedCall(s.fn, origCall, inlinedCall)
 					done = false
 					changed = true
 				}
diff --git a/src/cmd/compile/internal/ir/expr.go b/src/cmd/compile/internal/ir/expr.go
index 9d34f27ce53363..037957b676a033 100644
--- a/src/cmd/compile/internal/ir/expr.go
+++ b/src/cmd/compile/internal/ir/expr.go
@@ -677,6 +677,11 @@ type TypeAssertExpr struct {
 
 	// An internal/abi.TypeAssert descriptor to pass to the runtime.
 	Descriptor *obj.LSym
+
+	// When set to true, if this assert would panic, then use a nil pointer panic
+	// instead of an interface conversion panic.
+	// It must not be set for type asserts using the commaok form.
+	UseNilPanic bool
 }
 
 func NewTypeAssertExpr(pos src.XPos, x Node, typ *types.Type) *TypeAssertExpr {
diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index 41eb2dce1cc50f..a8a45b02697079 100644
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -2961,6 +2961,7 @@ func (r *reader) multiExpr() []ir.Node {
 		as.Def = true
 		for i := range results {
 			tmp := r.temp(pos, r.typ())
+			tmp.Defn = as
 			as.PtrInit().Append(ir.NewDecl(pos, ir.ODCL, tmp))
 			as.Lhs.Append(tmp)
 
diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 1e2159579dfbf2..6c4afb78959791 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -5827,6 +5827,25 @@ func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Val
 	if n.ITab != nil {
 		targetItab = s.expr(n.ITab)
 	}
+
+	if n.UseNilPanic {
+		if commaok {
+			base.Fatalf("unexpected *ir.TypeAssertExpr with UseNilPanic == true && commaok == true")
+		}
+		if n.Type().IsInterface() {
+			// Currently we do not expect the compiler to emit type asserts with UseNilPanic, that assert to an interface type.
+			// If needed, this can be relaxed in the future, but for now we can assert that.
+			base.Fatalf("unexpected *ir.TypeAssertExpr with UseNilPanic == true && Type().IsInterface() == true")
+		}
+		typs := s.f.Config.Types
+		iface = s.newValue2(
+			ssa.OpIMake,
+			iface.Type,
+			s.nilCheck(s.newValue1(ssa.OpITab, typs.BytePtr, iface)),
+			s.newValue1(ssa.OpIData, typs.BytePtr, iface),
+		)
+	}
+
 	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, nil, target, targetItab, commaok, n.Descriptor)
 }
 
diff --git a/src/crypto/sha256/sha256_test.go b/src/crypto/sha256/sha256_test.go
index 11b24db7d6b0a0..a18a536ba2896f 100644
--- a/src/crypto/sha256/sha256_test.go
+++ b/src/crypto/sha256/sha256_test.go
@@ -471,3 +471,17 @@ func BenchmarkHash256K(b *testing.B) {
 func BenchmarkHash1M(b *testing.B) {
 	benchmarkSize(b, 1024*1024)
 }
+
+func TestAllocatonsWithTypeAsserts(t *testing.T) {
+	cryptotest.SkipTestAllocations(t)
+	allocs := testing.AllocsPerRun(100, func() {
+		h := New()
+		h.Write([]byte{1, 2, 3})
+		marshaled, _ := h.(encoding.BinaryMarshaler).MarshalBinary()
+		marshaled, _ = h.(encoding.BinaryAppender).AppendBinary(marshaled[:0])
+		h.(encoding.BinaryUnmarshaler).UnmarshalBinary(marshaled)
+	})
+	if allocs != 0 {
+		t.Fatalf("allocs = %v; want = 0", allocs)
+	}
+}
diff --git a/src/runtime/pprof/pprof_test.go b/src/runtime/pprof/pprof_test.go
index 25a2f3b32415d7..a538627099034e 100644
--- a/src/runtime/pprof/pprof_test.go
+++ b/src/runtime/pprof/pprof_test.go
@@ -344,6 +344,11 @@ func (h inlineWrapper) dump(pcs []uintptr) {
 
 func inlinedWrapperCallerDump(pcs []uintptr) {
 	var h inlineWrapperInterface
+
+	// Take the address of h, such that h.dump() call (below)
+	// does not get devirtualized by the compiler.
+	_ = &h
+
 	h = &inlineWrapper{}
 	h.dump(pcs)
 }
diff --git a/test/devirtualization.go b/test/devirtualization.go
new file mode 100644
index 00000000000000..e3319052945e00
--- /dev/null
+++ b/test/devirtualization.go
@@ -0,0 +1,1277 @@
+// errorcheck -0 -m
+
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package escape
+
+type M interface{ M() }
+
+type A interface{ A() }
+
+type C interface{ C() }
+
+type Impl struct{}
+
+func (*Impl) M() {} // ERROR "can inline \(\*Impl\).M$"
+
+func (*Impl) A() {} // ERROR "can inline \(\*Impl\).A$"
+
+type Impl2 struct{}
+
+func (*Impl2) M() {} // ERROR "can inline \(\*Impl2\).M$"
+
+func (*Impl2) A() {} // ERROR "can inline \(\*Impl2\).A$"
+
+type CImpl struct{}
+
+func (CImpl) C() {} // ERROR "can inline CImpl.C$"
+
+func typeAsserts() {
+	var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+
+	a.(M).M()     // ERROR "devirtualizing a.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	a.(A).A()     // ERROR "devirtualizing a.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	a.(*Impl).M() // ERROR "inlining call to \(\*Impl\).M"
+	a.(*Impl).A() // ERROR "inlining call to \(\*Impl\).A"
+
+	v := a.(M)
+	v.M()         // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+	v.(A).A()     // ERROR "devirtualizing v.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	v.(*Impl).A() // ERROR "inlining call to \(\*Impl\).A"
+	v.(*Impl).M() // ERROR "inlining call to \(\*Impl\).M"
+
+	v2 := a.(A)
+	v2.A()         // ERROR "devirtualizing v2.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	v2.(M).M()     // ERROR "devirtualizing v2.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	v2.(*Impl).A() // ERROR "inlining call to \(\*Impl\).A"
+	v2.(*Impl).M() // ERROR "inlining call to \(\*Impl\).M"
+
+	a.(M).(A).A() // ERROR "devirtualizing a.\(M\).\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	a.(A).(M).M() // ERROR "devirtualizing a.\(A\).\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+
+	a.(M).(A).(*Impl).A() // ERROR "inlining call to \(\*Impl\).A"
+	a.(A).(M).(*Impl).M() // ERROR "inlining call to \(\*Impl\).M"
+
+	any(a).(M).M()           // ERROR "devirtualizing any\(a\).\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	any(a).(A).A()           // ERROR "devirtualizing any\(a\).\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	any(a).(M).(any).(A).A() // ERROR "devirtualizing any\(a\).\(M\).\(any\).\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+
+	c := any(a)
+	c.(A).A() // ERROR "devirtualizing c.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	c.(M).M() // ERROR "devirtualizing c.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+
+	M(a).M()    // ERROR "devirtualizing M\(a\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	M(M(a)).M() // ERROR "devirtualizing M\(M\(a\)\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+
+	a2 := a.(A)
+	A(a2).A()    // ERROR "devirtualizing A\(a2\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	A(A(a2)).A() // ERROR "devirtualizing A\(A\(a2\)\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+
+	{
+		var a C = &CImpl{}   // ERROR "&CImpl{} does not escape$"
+		a.(any).(C).C()      // ERROR "devirtualizing a.\(any\).\(C\).C to \*CImpl$" "inlining call to CImpl.C"
+		a.(any).(*CImpl).C() // ERROR "inlining call to CImpl.C"
+	}
+}
+
+func typeAssertsWithOkReturn() {
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		if v, ok := a.(M); ok {
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		}
+	}
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		if v, ok := a.(A); ok {
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+	}
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		v, ok := a.(M)
+		if ok {
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		}
+	}
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		v, ok := a.(A)
+		if ok {
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+	}
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		v, ok := a.(*Impl)
+		if ok {
+			v.A() // ERROR "inlining call to \(\*Impl\).A"
+			v.M() // ERROR "inlining call to \(\*Impl\).M"
+		}
+	}
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		v, _ := a.(M)
+		v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		v, _ := a.(A)
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		v, _ := a.(*Impl)
+		v.A() // ERROR "inlining call to \(\*Impl\).A"
+		v.M() // ERROR "inlining call to \(\*Impl\).M"
+	}
+	{
+		a := newM() // ERROR "&Impl{} does not escape$" "inlining call to newM"
+		callA(a)    // ERROR "devirtualizing m.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A" "inlining call to callA"
+		callIfA(a)  // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A" "inlining call to callIfA"
+	}
+	{
+		_, a := newM2ret() // ERROR "&Impl{} does not escape$" "inlining call to newM2ret"
+		callA(a)           // ERROR "devirtualizing m.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A" "inlining call to callA"
+		callIfA(a)         // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A" "inlining call to callIfA"
+	}
+	{
+		var a M = &Impl{} // ERROR "&Impl{} does not escape$"
+		// Note the !ok condition, devirtualizing here is fine.
+		if v, ok := a.(M); !ok {
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		}
+	}
+	{
+		var a A = newImplNoInline()
+		if v, ok := a.(M); ok {
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		}
+	}
+	{
+		var impl2InA A = &Impl2{} // ERROR "&Impl2{} does not escape$"
+		var a A
+		a, _ = impl2InA.(*Impl)
+		// a now contains the zero value of *Impl
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		a := newANoInline()
+		a.A()
+	}
+	{
+		_, a := newANoInlineRet2()
+		a.A()
+	}
+}
+
+func newM() M { // ERROR "can inline newM$"
+	return &Impl{} // ERROR "&Impl{} escapes to heap$"
+}
+
+func newM2ret() (int, M) { // ERROR "can inline newM2ret$"
+	return -1, &Impl{} // ERROR "&Impl{} escapes to heap$"
+}
+
+func callA(m M) { // ERROR "can inline callA$" "leaking param: m$"
+	m.(A).A()
+}
+
+func callIfA(m M) { // ERROR "can inline callIfA$" "leaking param: m$"
+	if v, ok := m.(A); ok {
+		v.A()
+	}
+}
+
+//go:noinline
+func newImplNoInline() *Impl {
+	return &Impl{} // ERROR "&Impl{} escapes to heap$"
+}
+
+//go:noinline
+func newImpl2ret2() (string, *Impl2) {
+	return "str", &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+}
+
+//go:noinline
+func newImpl2() *Impl2 {
+	return &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+}
+
+//go:noinline
+func newANoInline() A {
+	return &Impl{} // ERROR "&Impl{} escapes to heap$"
+}
+
+//go:noinline
+func newANoInlineRet2() (string, A) {
+	return "", &Impl{} // ERROR "&Impl{} escapes to heap$"
+}
+
+func testTypeSwitch() {
+	{
+		var v A = &Impl{} // ERROR "&Impl{} does not escape$"
+		switch v := v.(type) {
+		case A:
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		case M:
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		}
+	}
+	{
+		var v A = &Impl{} // ERROR "&Impl{} does not escape$"
+		switch v := v.(type) {
+		case A:
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		case M:
+			v.M()       // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+			v = &Impl{} // ERROR "&Impl{} does not escape$"
+			v.M()       // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		}
+		v.(M).M() // ERROR "devirtualizing v.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+	{
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		switch v1 := v.(type) {
+		case A:
+			v1.A()
+		case M:
+			v1.M()
+			v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		}
+	}
+	{
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		switch v := v.(type) {
+		case A:
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		case M:
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		case C:
+			v.C()
+		}
+	}
+	{
+		var v A = &Impl{} // ERROR "&Impl{} does not escape$"
+		switch v := v.(type) {
+		case M:
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		default:
+			panic("does not implement M") // ERROR ".does not implement M. escapes to heap$"
+		}
+	}
+}
+
+func differentTypeAssign() {
+	{
+		var a A
+		a = &Impl{}  // ERROR "&Impl{} escapes to heap$"
+		a = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		a.A()
+	}
+	{
+		a := A(&Impl{}) // ERROR "&Impl{} escapes to heap$"
+		a = &Impl2{}    // ERROR "&Impl2{} escapes to heap$"
+		a.A()
+	}
+	{
+		a := A(&Impl{}) // ERROR "&Impl{} escapes to heap$"
+		a.A()
+		a = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+	}
+	{
+		a := A(&Impl{}) // ERROR "&Impl{} escapes to heap$"
+		a = &Impl2{}    // ERROR "&Impl2{} escapes to heap$"
+		var asAny any = a
+		asAny.(A).A()
+	}
+	{
+		a := A(&Impl{}) // ERROR "&Impl{} escapes to heap$"
+		var asAny any = a
+		asAny = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		asAny.(A).A()
+	}
+	{
+		a := A(&Impl{}) // ERROR "&Impl{} escapes to heap$"
+		var asAny any = a
+		asAny.(A).A()
+		asAny = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		a.A()            // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a A
+		a = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		a = newImpl2()
+		a.A()
+	}
+	{
+		var a A
+		a = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		_, a = newImpl2ret2()
+		a.A()
+	}
+}
+
+func assignWithTypeAssert() {
+	{
+		var i1 A = &Impl{}  // ERROR "&Impl{} does not escape$"
+		var i2 A = &Impl2{} // ERROR "&Impl2{} does not escape$"
+		i1 = i2.(*Impl)     // this will panic
+		i1.A()              // ERROR "devirtualizing i1.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		i2.A()              // ERROR "devirtualizing i2.A to \*Impl2$" "inlining call to \(\*Impl2\).A"
+	}
+	{
+		var i1 A = &Impl{}  // ERROR "&Impl{} does not escape$"
+		var i2 A = &Impl2{} // ERROR "&Impl2{} does not escape$"
+		i1, _ = i2.(*Impl)  // i1 is going to be nil
+		i1.A()              // ERROR "devirtualizing i1.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		i2.A()              // ERROR "devirtualizing i2.A to \*Impl2$" "inlining call to \(\*Impl2\).A"
+	}
+}
+
+func nilIface() {
+	{
+		var v A = &Impl{} // ERROR "&Impl{} does not escape$"
+		v = nil
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A = &Impl{} // ERROR "&Impl{} does not escape$"
+		v.A()             // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		v = nil
+	}
+	{
+		var nilIface A
+		var v A = &Impl{} // ERROR "&Impl{} does not escape$"
+		v.A()             // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		v = nilIface
+	}
+	{
+		var nilIface A
+		var v A = &Impl{} // ERROR "&Impl{} does not escape$"
+		v = nilIface
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		v.A()       // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		v = &Impl{} // ERROR "&Impl{} does not escape$"
+	}
+	{
+		var v A
+		var v2 A = v
+		v2.A()       // ERROR "devirtualizing v2.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		v2 = &Impl{} // ERROR "&Impl{} does not escape$"
+	}
+	{
+		var v A
+		v.A()
+	}
+	{
+		var v A
+		var v2 A = v
+		v2.A()
+	}
+	{
+		var v A
+		var v2 A
+		v2 = v
+		v2.A()
+	}
+}
+
+func longDevirtTest() {
+	var a interface {
+		M
+		A
+	} = &Impl{} // ERROR "&Impl{} does not escape$"
+
+	{
+		var b A = a
+		b.A()     // ERROR "devirtualizing b.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		b.(M).M() // ERROR "devirtualizing b.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+	{
+		var b M = a
+		b.M()     // ERROR "devirtualizing b.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		b.(A).A() // ERROR "devirtualizing b.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var b A = a.(M).(A)
+		b.A()     // ERROR "devirtualizing b.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		b.(M).M() // ERROR "devirtualizing b.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+	{
+		var b M = a.(A).(M)
+		b.M()     // ERROR "devirtualizing b.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		b.(A).A() // ERROR "devirtualizing b.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+
+	if v, ok := a.(A); ok {
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+
+	if v, ok := a.(M); ok {
+		v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+
+	{
+		var c A = a
+
+		if v, ok := c.(A); ok {
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+
+		c = &Impl{} // ERROR "&Impl{} does not escape$"
+
+		if v, ok := c.(M); ok {
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+		}
+
+		if v, ok := c.(interface {
+			A
+			M
+		}); ok {
+			v.M() // ERROR "devirtualizing v.M to \*Impl$" "inlining call to \(\*Impl\).M"
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+	}
+}
+
+func deferDevirt() {
+	var a A
+	defer func() { // ERROR "can inline deferDevirt.func1$" "func literal does not escape$"
+		a = &Impl{} // ERROR "&Impl{} escapes to heap$"
+	}()
+	a = &Impl{} // ERROR "&Impl{} does not escape$"
+	a.A()       // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+}
+
+func deferNoDevirt() {
+	var a A
+	defer func() { // ERROR "can inline deferNoDevirt.func1$" "func literal does not escape$"
+		a = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+	}()
+	a = &Impl{} // ERROR "&Impl{} escapes to heap$"
+	a.A()
+}
+
+//go:noinline
+func closureDevirt() {
+	var a A
+	func() { // ERROR "func literal does not escape$"
+		// defer so that it does not lnline.
+		defer func() {}() // ERROR "can inline closureDevirt.func1.1$" "func literal does not escape$"
+		a = &Impl{}       // ERROR "&Impl{} escapes to heap$"
+	}()
+	a = &Impl{} // ERROR "&Impl{} does not escape$"
+	a.A()       // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+}
+
+//go:noinline
+func closureNoDevirt() {
+	var a A
+	func() { // ERROR "func literal does not escape$"
+		// defer so that it does not lnline.
+		defer func() {}() // ERROR "can inline closureNoDevirt.func1.1$" "func literal does not escape$"
+		a = &Impl2{}      // ERROR "&Impl2{} escapes to heap$"
+	}()
+	a = &Impl{} // ERROR "&Impl{} escapes to heap$"
+	a.A()
+}
+
+var global = "1"
+
+func closureDevirt2() {
+	var a A
+	a = &Impl{}   // ERROR "&Impl{} does not escape$"
+	c := func() { // ERROR "can inline closureDevirt2.func1$" "func literal does not escape$"
+		a = &Impl{} // ERROR "&Impl{} escapes to heap$"
+	}
+	if global == "1" {
+		c = func() { // ERROR "can inline closureDevirt2.func2$" "func literal does not escape$"
+			a = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		}
+	}
+	a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	c()
+}
+
+func closureNoDevirt2() {
+	var a A
+	a = &Impl{}   // ERROR "&Impl{} escapes to heap$"
+	c := func() { // ERROR "can inline closureNoDevirt2.func1$" "func literal does not escape$"
+		a = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+	}
+	if global == "1" {
+		c = func() { // ERROR "can inline closureNoDevirt2.func2$" "func literal does not escape$"
+			a = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		}
+	}
+	a.A()
+	c()
+}
+
+//go:noinline
+func closureDevirt3() {
+	var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+	func() {          // ERROR "func literal does not escape$"
+		// defer so that it does not lnline.
+		defer func() {}() // ERROR "can inline closureDevirt3.func1.1$" "func literal does not escape$"
+		a.A()             // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}()
+	func() { // ERROR "can inline closureDevirt3.func2$"
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}() // ERROR "inlining call to closureDevirt3.func2" "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+}
+
+//go:noinline
+func closureNoDevirt3() {
+	var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+	func() {          // ERROR "func literal does not escape$"
+		// defer so that it does not lnline.
+		defer func() {}() // ERROR "can inline closureNoDevirt3.func1.1$" "func literal does not escape$"
+		a.A()
+	}()
+	func() { // ERROR "can inline closureNoDevirt3.func2$"
+		a.A()
+	}() // ERROR "inlining call to closureNoDevirt3.func2"
+	a = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+}
+
+//go:noinline
+func varDeclaredInClosureReferencesOuter() {
+	var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+	func() {          // ERROR "func literal does not escape$"
+		// defer for noinline
+		defer func() {}() // ERROR "can inline varDeclaredInClosureReferencesOuter.func1.1$" "func literal does not escape$"
+		var v A = a
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}()
+	func() { // ERROR "func literal does not escape$"
+		// defer for noinline
+		defer func() {}() // ERROR "can inline varDeclaredInClosureReferencesOuter.func2.1$" "func literal does not escape$"
+		var v A = a
+		v = &Impl{} // ERROR "&Impl{} does not escape$"
+		v.A()       // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}()
+
+	var b A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+	func() {          // ERROR "func literal does not escape$"
+		// defer for noinline
+		defer func() {}() // ERROR "can inline varDeclaredInClosureReferencesOuter.func3.1$" "func literal does not escape$"
+		var v A = b
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		v.A()
+	}()
+	func() { // ERROR "func literal does not escape$"
+		// defer for noinline
+		defer func() {}() // ERROR "can inline varDeclaredInClosureReferencesOuter.func4.1$" "func literal does not escape$"
+		var v A = b
+		v.A()
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+	}()
+}
+
+//go:noinline
+func testNamedReturn0() (v A) {
+	v = &Impl{} // ERROR "&Impl{} escapes to heap$"
+	v.A()
+	return
+}
+
+//go:noinline
+func testNamedReturn1() (v A) {
+	v = &Impl{} // ERROR "&Impl{} escapes to heap$"
+	v.A()
+	return &Impl{} // ERROR "&Impl{} escapes to heap$"
+}
+
+func testNamedReturns3() (v A) {
+	v = &Impl{}    // ERROR "&Impl{} escapes to heap$"
+	defer func() { // ERROR "can inline testNamedReturns3.func1$" "func literal does not escape$"
+		v.A()
+	}()
+	v.A()
+	return &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+}
+
+var (
+	globalImpl    = &Impl{}
+	globalImpl2   = &Impl2{}
+	globalA     A = &Impl{}
+	globalM     M = &Impl{}
+)
+
+func globals() {
+	{
+		globalA.A()
+		globalA.(M).M()
+		globalM.M()
+		globalM.(A).A()
+
+		a := globalA
+		a.A()
+		a.(M).M()
+
+		m := globalM
+		m.M()
+		m.(A).A()
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+		a = globalImpl
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+		a = A(globalImpl)
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+		a = M(globalImpl).(A)
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+		a = globalA.(*Impl)
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		a = globalM.(*Impl)
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		a = globalImpl2
+		a.A()
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		a = globalA
+		a.A()
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		a = globalM.(A)
+		a.A()
+	}
+}
+
+func mapsDevirt() {
+	{
+		m := make(map[int]*Impl) // ERROR "make\(map\[int\]\*Impl\) does not escape$"
+		var v A = m[0]
+		v.A()     // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		v.(M).M() // ERROR "devirtualizing v.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+	{
+		m := make(map[int]*Impl) // ERROR "make\(map\[int\]\*Impl\) does not escape$"
+		var v A
+		var ok bool
+		if v, ok = m[0]; ok {
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		m := make(map[int]*Impl) // ERROR "make\(map\[int\]\*Impl\) does not escape$"
+		var v A
+		v, _ = m[0]
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+}
+
+func mapsNoDevirt() {
+	{
+		m := make(map[int]*Impl) // ERROR "make\(map\[int\]\*Impl\) does not escape$"
+		var v A = m[0]
+		v.A()
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		v.(M).M()
+	}
+	{
+		m := make(map[int]*Impl) // ERROR "make\(map\[int\]\*Impl\) does not escape$"
+		var v A
+		var ok bool
+		if v, ok = m[0]; ok {
+			v.A()
+		}
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		v.A()
+	}
+	{
+		m := make(map[int]*Impl) // ERROR "make\(map\[int\]\*Impl\) does not escape$"
+		var v A = &Impl{}        // ERROR "&Impl{} escapes to heap$"
+		v, _ = m[0]
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		v.A()
+	}
+
+	{
+		m := make(map[int]A) // ERROR "make\(map\[int\]A\) does not escape$"
+		var v A = &Impl{}    // ERROR "&Impl{} escapes to heap$"
+		v = m[0]
+		v.A()
+	}
+	{
+		m := make(map[int]A) // ERROR "make\(map\[int\]A\) does not escape$"
+		var v A = &Impl{}    // ERROR "&Impl{} escapes to heap$"
+		var ok bool
+		if v, ok = m[0]; ok {
+			v.A()
+		}
+		v.A()
+	}
+	{
+		m := make(map[int]A) // ERROR "make\(map\[int\]A\) does not escape$"
+		var v A = &Impl{}    // ERROR "&Impl{} escapes to heap$"
+		v, _ = m[0]
+		v.A()
+	}
+}
+
+func chanDevirt() {
+	{
+		m := make(chan *Impl)
+		var v A = <-m
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		m := make(chan *Impl)
+		var v A
+		v = <-m
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		m := make(chan *Impl)
+		var v A
+		v, _ = <-m
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		m := make(chan *Impl)
+		var v A
+		var ok bool
+		if v, ok = <-m; ok {
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		m := make(chan *Impl)
+		var v A
+		var ok bool
+		if v, ok = <-m; ok {
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+		select {
+		case <-m:
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		case v = <-m:
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		case v, ok = <-m:
+			v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+	}
+}
+
+func chanNoDevirt() {
+	{
+		m := make(chan *Impl)
+		var v A = <-m
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		v.A()
+	}
+	{
+		m := make(chan *Impl)
+		var v A
+		v = <-m
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		v.A()
+	}
+	{
+		m := make(chan *Impl)
+		var v A
+		v, _ = <-m
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		v.A()
+	}
+	{
+		m := make(chan *Impl)
+		var v A
+		var ok bool
+		if v, ok = <-m; ok {
+			v.A()
+		}
+		v = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		v.A()
+	}
+	{
+		m := make(chan *Impl)
+		var v A = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		var ok bool
+		if v, ok = <-m; ok {
+			v.A()
+		}
+	}
+	{
+		m := make(chan *Impl)
+		var v A = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		select {
+		case v = <-m:
+			v.A()
+		}
+		v.A()
+	}
+	{
+		m := make(chan *Impl)
+		var v A = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		select {
+		case v, _ = <-m:
+			v.A()
+		}
+		v.A()
+	}
+
+	{
+		m := make(chan A)
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		v = <-m
+		v.A()
+	}
+	{
+		m := make(chan A)
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		v, _ = <-m
+		v.A()
+	}
+	{
+		m := make(chan A)
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		var ok bool
+		if v, ok = <-m; ok {
+			v.A()
+		}
+	}
+	{
+		m := make(chan A)
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		select {
+		case v = <-m:
+			v.A()
+		}
+		v.A()
+	}
+	{
+		m := make(chan A)
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		select {
+		case v, _ = <-m:
+			v.A()
+		}
+		v.A()
+	}
+}
+
+func rangeDevirt() {
+	{
+		var v A
+		m := make(map[*Impl]struct{}) // ERROR "make\(map\[\*Impl\]struct {}\) does not escape$"
+		v = &Impl{}                   // ERROR "&Impl{} does not escape$"
+		for v = range m {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		m := make(map[*Impl]*Impl) // ERROR "make\(map\[\*Impl\]\*Impl\) does not escape$"
+		v = &Impl{}                // ERROR "&Impl{} does not escape$"
+		for v = range m {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		m := make(map[*Impl]*Impl) // ERROR "make\(map\[\*Impl\]\*Impl\) does not escape$"
+		v = &Impl{}                // ERROR "&Impl{} does not escape$"
+		for _, v = range m {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		m := make(chan *Impl)
+		v = &Impl{} // ERROR "&Impl{} does not escape$"
+		for v = range m {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		m := []*Impl{} // ERROR "\[\]\*Impl{} does not escape$"
+		v = &Impl{}    // ERROR "&Impl{} does not escape$"
+		for _, v = range m {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		v = &Impl{}     // ERROR "&Impl{} does not escape$"
+		impl := &Impl{} // ERROR "&Impl{} does not escape$"
+		i := 0
+		for v = impl; i < 10; i++ {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		v = &Impl{}     // ERROR "&Impl{} does not escape$"
+		impl := &Impl{} // ERROR "&Impl{} does not escape$"
+		i := 0
+		for v = impl; i < 10; i++ {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		m := [1]*Impl{&Impl{}} // ERROR "&Impl{} does not escape$"
+		v = &Impl{}            // ERROR "&Impl{} does not escape$"
+		for _, v = range m {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var v A
+		m := [1]*Impl{&Impl{}} // ERROR "&Impl{} does not escape$"
+		v = &Impl{}            // ERROR "&Impl{} does not escape$"
+		for _, v = range &m {
+		}
+		v.A() // ERROR "devirtualizing v.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+}
+
+func rangeNoDevirt() {
+	{
+		var v A = &Impl2{}            // ERROR "&Impl2{} escapes to heap$"
+		m := make(map[*Impl]struct{}) // ERROR "make\(map\[\*Impl\]struct {}\) does not escape$"
+		for v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A = &Impl2{}         // ERROR "&Impl2{} escapes to heap$"
+		m := make(map[*Impl]*Impl) // ERROR "make\(map\[\*Impl\]\*Impl\) does not escape$"
+		for v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A = &Impl2{}         // ERROR "&Impl2{} escapes to heap$"
+		m := make(map[*Impl]*Impl) // ERROR "make\(map\[\*Impl\]\*Impl\) does not escape$"
+		for _, v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		m := make(chan *Impl)
+		for v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		m := []*Impl{}     // ERROR "\[\]\*Impl{} does not escape$"
+		for _, v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A
+		v = &Impl2{}    // ERROR "&Impl2{} escapes to heap$"
+		impl := &Impl{} // ERROR "&Impl{} escapes to heap$"
+		i := 0
+		for v = impl; i < 10; i++ {
+		}
+		v.A()
+	}
+	{
+		var v A
+		v = &Impl2{}    // ERROR "&Impl2{} escapes to heap$"
+		impl := &Impl{} // ERROR "&Impl{} escapes to heap$"
+		i := 0
+		for v = impl; i < 10; i++ {
+		}
+		v.A()
+	}
+	{
+		var v A
+		m := [1]*Impl{&Impl{}} // ERROR "&Impl{} escapes to heap$"
+		v = &Impl2{}           // ERROR "&Impl2{} escapes to heap$"
+		for _, v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A
+		m := [1]*Impl{&Impl{}} // ERROR "&Impl{} escapes to heap$"
+		v = &Impl2{}           // ERROR "&Impl2{} escapes to heap$"
+		for _, v = range &m {
+		}
+		v.A()
+	}
+
+	{
+		var v A = &Impl{}         // ERROR "&Impl{} escapes to heap$"
+		m := make(map[A]struct{}) // ERROR "make\(map\[A\]struct {}\) does not escape$"
+		for v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A = &Impl{}  // ERROR "&Impl{} escapes to heap$"
+		m := make(map[A]A) // ERROR "make\(map\[A\]A\) does not escape$"
+		for v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A = &Impl{}  // ERROR "&Impl{} escapes to heap$"
+		m := make(map[A]A) // ERROR "make\(map\[A\]A\) does not escape$"
+		for _, v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		m := make(chan A)
+		for v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		m := []A{}        // ERROR "\[\]A{} does not escape$"
+		for _, v = range m {
+		}
+		v.A()
+	}
+
+	{
+		var v A
+		m := [1]A{&Impl{}} // ERROR "&Impl{} escapes to heap$"
+		v = &Impl{}        // ERROR "&Impl{} escapes to heap$"
+		for _, v = range m {
+		}
+		v.A()
+	}
+	{
+		var v A
+		m := [1]A{&Impl{}} // ERROR "&Impl{} escapes to heap$"
+		v = &Impl{}        // ERROR "&Impl{} escapes to heap$"
+		for _, v = range &m {
+		}
+		v.A()
+	}
+}
+
+var globalInt = 1
+
+func testIfInit() {
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+		var i = &Impl{}   // ERROR "&Impl{} does not escape$"
+		if a = i; globalInt == 1 {
+			a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+		a.A()     // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		a.(M).M() // ERROR "devirtualizing a.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		var i2 = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		if a = i2; globalInt == 1 {
+			a.A()
+		}
+		a.A()
+	}
+}
+
+func testSwitchInit() {
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+		var i = &Impl{}   // ERROR "&Impl{} does not escape$"
+		switch a = i; globalInt {
+		case 12:
+			a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		}
+		a.A()     // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+		a.(M).M() // ERROR "devirtualizing a.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		var i2 = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		switch a = i2; globalInt {
+		case 12:
+			a.A()
+		}
+		a.A()
+	}
+}
+
+type implWrapper Impl
+
+func (implWrapper) A() {} // ERROR "can inline implWrapper.A$"
+
+//go:noinline
+func devirtWrapperType() {
+	{
+		i := &Impl{} // ERROR "&Impl{} does not escape$"
+		// This is an OCONVNOP, so we have to be careful, not to devirtualize it to Impl.A.
+		var a A = (*implWrapper)(i)
+		a.A() // ERROR "devirtualizing a.A to \*implWrapper$" "inlining call to implWrapper.A"
+	}
+	{
+		i := Impl{}
+		// This is an OCONVNOP, so we have to be careful, not to devirtualize it to Impl.A.
+		var a A = (implWrapper)(i) // ERROR "implWrapper\(i\) does not escape$"
+		a.A()                      // ERROR "devirtualizing a.A to implWrapper$" "inlining call to implWrapper.A"
+	}
+}
+
+func selfAssigns() {
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape$"
+		a = a
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape"
+		var asAny any = a
+		asAny = asAny
+		asAny.(A).A() // ERROR "devirtualizing asAny.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape"
+		var asAny any = a
+		a = asAny.(A)
+		asAny.(A).A() // ERROR "devirtualizing asAny.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+		a.(A).A()     // ERROR "devirtualizing a.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+		b := a
+		b.(A).A() // ERROR "devirtualizing b.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape"
+		var asAny any = a
+		asAny = asAny
+		a = asAny.(A)
+		asAny = a
+		asAny.(A).A() // ERROR "devirtualizing asAny.\(A\).A to \*Impl$" "inlining call to \(\*Impl\).A"
+		asAny.(M).M() // ERROR "devirtualizing asAny.\(M\).M to \*Impl$" "inlining call to \(\*Impl\).M"
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} does not escape"
+		var asAny A = a
+		a = asAny.(A)
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+	{
+		var a, b, c A
+		c = &Impl{} // ERROR "&Impl{} does not escape$"
+		a = c
+		c = b
+		b = c
+		a = b
+		b = a
+		c = a
+		a.A() // ERROR "devirtualizing a.A to \*Impl$" "inlining call to \(\*Impl\).A"
+	}
+}
+
+func boolNoDevirt() {
+	{
+		m := make(map[int]*Impl) // ERROR "make\(map\[int\]\*Impl\) does not escape$"
+		var v any = &Impl{}      // ERROR "&Impl{} escapes to heap$"
+		_, v = m[0]              // ERROR ".autotmp_[0-9]+ escapes to heap$"
+		v.(A).A()
+	}
+	{
+		m := make(chan *Impl)
+		var v any = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		select {
+		case _, v = <-m: // ERROR ".autotmp_[0-9]+ escapes to heap$"
+		}
+		v.(A).A()
+	}
+	{
+		m := make(chan *Impl)
+		var v any = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		_, v = <-m          // ERROR ".autotmp_[0-9]+ escapes to heap$"
+		v.(A).A()
+	}
+	{
+		var a any = 4       // ERROR "4 does not escape$"
+		var v any = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		_, v = a.(int)      // ERROR ".autotmp_[0-9]+ escapes to heap$"
+		v.(A).A()
+	}
+}
+
+func addrTaken() {
+	{
+		var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		var ptrA = &a
+		a.A()
+		_ = ptrA
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		var ptrA = &a
+		*ptrA = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		a.A()
+	}
+	{
+		var a A = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		var ptrA = &a
+		*ptrA = &Impl2{} // ERROR "&Impl2{} escapes to heap$"
+		a.A()
+	}
+}
+
+func testInvalidAsserts() {
+	any(0).(interface{ A() }).A() // ERROR "any\(0\) escapes to heap$"
+	{
+		var a M = &Impl{} // ERROR "&Impl{} escapes to heap$"
+		a.(C).C()         // this will panic
+		a.(any).(C).C()   // this will panic
+	}
+	{
+		var a C = &CImpl{} // ERROR "&CImpl{} escapes to heap$"
+		a.(M).M()          // this will panic
+		a.(any).(M).M()    // this will panic
+	}
+	{
+		var a C = &CImpl{} // ERROR "&CImpl{} does not escape$"
+
+		// this will panic
+		a.(M).(*Impl).M() // ERROR "inlining call to \(\*Impl\).M"
+
+		// this will panic
+		a.(any).(M).(*Impl).M() // ERROR "inlining call to \(\*Impl\).M"
+	}
+}
+
+type namedBool bool
+
+func (namedBool) M() {} // ERROR "can inline namedBool.M$"
+
+//go:noinline
+func namedBoolTest() {
+	m := map[int]int{} // ERROR "map\[int\]int{} does not escape"
+	var ok namedBool
+	_, ok = m[5]
+	var i M = ok // ERROR "ok does not escape"
+	i.M()        // ERROR "devirtualizing i.M to namedBool$" "inlining call to namedBool.M"
+}
diff --git a/test/devirtualization_nil_panics.go b/test/devirtualization_nil_panics.go
new file mode 100644
index 00000000000000..59da454be7f910
--- /dev/null
+++ b/test/devirtualization_nil_panics.go
@@ -0,0 +1,100 @@
+// run
+
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"fmt"
+	"runtime"
+	"strings"
+)
+
+type A interface{ A() }
+
+type Impl struct{}
+
+func (*Impl) A() {}
+
+type Impl2 struct{}
+
+func (*Impl2) A() {}
+
+func main() {
+	shouldNilPanic(28, func() {
+		var v A
+		v.A()
+		v = &Impl{}
+	})
+	shouldNilPanic(36, func() {
+		var v A
+		defer func() {
+			v = &Impl{}
+		}()
+		v.A()
+	})
+	shouldNilPanic(43, func() {
+		var v A
+		f := func() {
+			v = &Impl{}
+		}
+		v.A()
+		f()
+	})
+
+	// Make sure that both devirtualized and non devirtualized
+	// variants have the panic at the same line.
+	shouldNilPanic(55, func() {
+		var v A
+		defer func() {
+			v = &Impl{}
+		}()
+		v. // A() is on a sepearate line
+			A()
+	})
+	shouldNilPanic(64, func() {
+		var v A
+		defer func() {
+			v = &Impl{}
+			v = &Impl2{} // assign different type, such that the call below does not get devirtualized
+		}()
+		v. // A() is on a sepearate line
+			A()
+	})
+}
+
+var cnt = 0
+
+func shouldNilPanic(wantLine int, f func()) {
+	cnt++
+	defer func() {
+		p := recover()
+		if p == nil {
+			panic("no nil deref panic")
+		}
+		if strings.Contains(fmt.Sprintf("%s", p), "invalid memory address or nil pointer dereference") {
+			callers := make([]uintptr, 128)
+			n := runtime.Callers(0, callers)
+			callers = callers[:n]
+
+			frames := runtime.CallersFrames(callers)
+			line := -1
+			for f, next := frames.Next(); next; f, next = frames.Next() {
+				if f.Func.Name() == fmt.Sprintf("main.main.func%v", cnt) {
+					line = f.Line
+					break
+				}
+			}
+
+			if line != wantLine {
+				panic(fmt.Sprintf("invalid line number in panic = %v; want = %v", line, wantLine))
+			}
+
+			return
+		}
+		panic(p)
+	}()
+	f()
+}
diff --git a/test/devirtualization_with_type_assertions_interleaved.go b/test/devirtualization_with_type_assertions_interleaved.go
new file mode 100644
index 00000000000000..6bad3beb9aa0d2
--- /dev/null
+++ b/test/devirtualization_with_type_assertions_interleaved.go
@@ -0,0 +1,139 @@
+// errorcheck -0 -m
+
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package escape
+
+type hashIface interface {
+	Sum() []byte
+}
+
+type cloneableHashIface interface {
+	hashIface
+	Clone() hashIface
+}
+
+type hash struct{ state [32]byte }
+
+func (h *hash) Sum() []byte { // ERROR "can inline \(\*hash\).Sum$" "h does not escape$"
+	return make([]byte, 32) // ERROR "make\(\[\]byte, 32\) escapes to heap$"
+}
+
+func (h *hash) Clone() hashIface { // ERROR "can inline \(\*hash\).Clone$" "h does not escape$"
+	c := *h // ERROR "moved to heap: c$"
+	return &c
+}
+
+type hash2 struct{ state [32]byte }
+
+func (h *hash2) Sum() []byte { // ERROR "can inline \(\*hash2\).Sum$" "h does not escape$"
+	return make([]byte, 32) // ERROR "make\(\[\]byte, 32\) escapes to heap$"
+}
+
+func (h *hash2) Clone() hashIface { // ERROR "can inline \(\*hash2\).Clone$" "h does not escape$"
+	c := *h // ERROR "moved to heap: c$"
+	return &c
+}
+
+func newHash() hashIface { // ERROR "can inline newHash$"
+	return &hash{} // ERROR "&hash{} escapes to heap$"
+}
+
+func cloneHash1(h hashIface) hashIface { // ERROR "can inline cloneHash1$" "leaking param: h$"
+	if h, ok := h.(cloneableHashIface); ok {
+		return h.Clone()
+	}
+	return &hash{} // ERROR "&hash{} escapes to heap$"
+}
+
+func cloneHash2(h hashIface) hashIface { // ERROR "can inline cloneHash2$" "leaking param: h$"
+	if h, ok := h.(cloneableHashIface); ok {
+		return h.Clone()
+	}
+	return nil
+}
+
+func cloneHash3(h hashIface) hashIface { // ERROR "can inline cloneHash3$" "leaking param: h$"
+	if h, ok := h.(cloneableHashIface); ok {
+		return h.Clone()
+	}
+	return &hash2{} // ERROR "&hash2{} escapes to heap$"
+}
+
+func cloneHashWithBool1(h hashIface) (hashIface, bool) { // ERROR "can inline cloneHashWithBool1$" "leaking param: h$"
+	if h, ok := h.(cloneableHashIface); ok {
+		return h.Clone(), true
+	}
+	return &hash{}, false // ERROR "&hash{} escapes to heap$"
+}
+
+func cloneHashWithBool2(h hashIface) (hashIface, bool) { // ERROR "can inline cloneHashWithBool2$" "leaking param: h$"
+	if h, ok := h.(cloneableHashIface); ok {
+		return h.Clone(), true
+	}
+	return nil, false
+}
+
+func cloneHashWithBool3(h hashIface) (hashIface, bool) { // ERROR "can inline cloneHashWithBool3$" "leaking param: h$"
+	if h, ok := h.(cloneableHashIface); ok {
+		return h.Clone(), true
+	}
+	return &hash2{}, false // ERROR "&hash2{} escapes to heap$"
+}
+
+func interleavedWithTypeAssertions() {
+	h1 := newHash() // ERROR "&hash{} does not escape$" "inlining call to newHash"
+	_ = h1.Sum()    // ERROR "devirtualizing h1.Sum to \*hash$" "inlining call to \(\*hash\).Sum" "make\(\[\]byte, 32\) does not escape$"
+
+	h2 := cloneHash1(h1) // ERROR "&hash{} does not escape$" "devirtualizing h.Clone to \*hash$" "inlining call to \(\*hash\).Clone" "inlining call to cloneHash1"
+	_ = h2.Sum()         // ERROR "devirtualizing h2.Sum to \*hash$" "inlining call to \(\*hash\).Sum" "make\(\[\]byte, 32\) does not escape$"
+
+	h3 := cloneHash2(h1) // ERROR "devirtualizing h.Clone to \*hash$" "inlining call to \(\*hash\).Clone" "inlining call to cloneHash2"
+	_ = h3.Sum()         // ERROR "devirtualizing h3.Sum to \*hash$" "inlining call to \(\*hash\).Sum" "make\(\[\]byte, 32\) does not escape$"
+
+	h4 := cloneHash3(h1) // ERROR "&hash2{} escapes to heap$" "devirtualizing h.Clone to \*hash$" "inlining call to \(\*hash\).Clone" "inlining call to cloneHash3" "moved to heap: c$"
+	_ = h4.Sum()
+
+	h5, _ := cloneHashWithBool1(h1) // ERROR "&hash{} does not escape$" "devirtualizing h.Clone to \*hash$" "inlining call to \(\*hash\).Clone" "inlining call to cloneHashWithBool1"
+	_ = h5.Sum()                    // ERROR "devirtualizing h5.Sum to \*hash$" "inlining call to \(\*hash\).Sum" "make\(\[\]byte, 32\) does not escape$"
+
+	h6, _ := cloneHashWithBool2(h1) // ERROR "devirtualizing h.Clone to \*hash$" "inlining call to \(\*hash\).Clone" "inlining call to cloneHashWithBool2"
+	_ = h6.Sum()                    // ERROR "devirtualizing h6.Sum to \*hash$" "inlining call to \(\*hash\).Sum" "make\(\[\]byte, 32\) does not escape$"
+
+	h7, _ := cloneHashWithBool3(h1) // ERROR "&hash2{} escapes to heap$" "devirtualizing h.Clone to \*hash$" "inlining call to \(\*hash\).Clone" "inlining call to cloneHashWithBool3" "moved to heap: c$"
+	_ = h7.Sum()
+}
+
+type cloneableHashError interface {
+	hashIface
+	Clone() (hashIface, error)
+}
+
+type hash3 struct{ state [32]byte }
+
+func newHash3() hashIface { // ERROR "can inline newHash3$"
+	return &hash3{} // ERROR "&hash3{} escapes to heap$"
+}
+
+func (h *hash3) Sum() []byte { // ERROR "can inline \(\*hash3\).Sum$" "h does not escape$"
+	return make([]byte, 32) // ERROR "make\(\[\]byte, 32\) escapes to heap$"
+}
+
+func (h *hash3) Clone() (hashIface, error) { // ERROR "can inline \(\*hash3\).Clone$" "h does not escape$"
+	c := *h // ERROR "moved to heap: c$"
+	return &c, nil
+}
+
+func interleavedCloneableHashError() {
+	h1 := newHash3() // ERROR "&hash3{} does not escape$" "inlining call to newHash3"
+	_ = h1.Sum()     // ERROR "devirtualizing h1.Sum to \*hash3$" "inlining call to \(\*hash3\).Sum" "make\(\[\]byte, 32\) does not escape$"
+
+	if h1, ok := h1.(cloneableHashError); ok {
+		h2, err := h1.Clone() // ERROR "devirtualizing h1.Clone to \*hash3$" "inlining call to \(\*hash3\).Clone"
+		if err == nil {
+			_ = h2.Sum() // ERROR "devirtualizing h2.Sum to \*hash3$" "inlining call to \(\*hash3\).Sum" "make\(\[\]byte, 32\) does not escape$"
+		}
+	}
+}
diff --git a/test/fixedbugs/issue42284.dir/a.go b/test/fixedbugs/issue42284.dir/a.go
index ccf54fad54a03c..e55f190d7ee571 100644
--- a/test/fixedbugs/issue42284.dir/a.go
+++ b/test/fixedbugs/issue42284.dir/a.go
@@ -22,9 +22,8 @@ func g() {
 	h := E() // ERROR "inlining call to E" "T\(0\) does not escape"
 	h.M()    // ERROR "devirtualizing h.M to T" "inlining call to T.M"
 
-	// BAD: T(0) could be stack allocated.
-	i := F(T(0)) // ERROR "inlining call to F" "T\(0\) escapes to heap"
+	i := F(T(0)) // ERROR "inlining call to F" "T\(0\) does not escape"
 
-	// Testing that we do NOT devirtualize here:
-	i.M()
+	// It is fine that we devirtualize here, as we add an additional nilcheck.
+	i.M() // ERROR "devirtualizing i.M to T" "inlining call to T.M"
 }
diff --git a/test/fixedbugs/issue42284.dir/b.go b/test/fixedbugs/issue42284.dir/b.go
index 559de59184460a..4a0b7cea102e88 100644
--- a/test/fixedbugs/issue42284.dir/b.go
+++ b/test/fixedbugs/issue42284.dir/b.go
@@ -10,9 +10,8 @@ func g() {
 	h := a.E() // ERROR "inlining call to a.E" "T\(0\) does not escape"
 	h.M()      // ERROR "devirtualizing h.M to a.T" "inlining call to a.T.M"
 
-	// BAD: T(0) could be stack allocated.
-	i := a.F(a.T(0)) // ERROR "inlining call to a.F" "a.T\(0\) escapes to heap"
+	i := a.F(a.T(0)) // ERROR "inlining call to a.F" "a.T\(0\) does not escape"
 
-	// Testing that we do NOT devirtualize here:
-	i.M()
+	// It is fine that we devirtualize here, as we add an additional nilcheck.
+	i.M() // ERROR "devirtualizing i.M to a.T" "inlining call to a.T.M"
 }

From ee163197a879cf19aa9758bc544c717445284311 Mon Sep 17 00:00:00 2001
From: Federico Guerinoni 
Date: Tue, 7 Oct 2025 01:13:14 +0200
Subject: [PATCH 104/229] path/filepath: return cleaned path from Rel

As the doc says, Rel should return a cleaned path.

Fixes #75763

Change-Id: Ic0f5a3b1da3cc4cf3c31fdb1a88ebcc4ea6f9169
Reviewed-on: https://go-review.googlesource.com/c/go/+/709675
Reviewed-by: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Sean Liao 
Auto-Submit: Sean Liao 
Reviewed-by: Carlos Amedee 
---
 src/path/filepath/path.go      | 2 +-
 src/path/filepath/path_test.go | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/path/filepath/path.go b/src/path/filepath/path.go
index 5ffd9f0b6c3fba..dc6975242a928c 100644
--- a/src/path/filepath/path.go
+++ b/src/path/filepath/path.go
@@ -248,7 +248,7 @@ func Rel(basepath, targpath string) (string, error) {
 			buf[n] = Separator
 			copy(buf[n+1:], targ[t0:])
 		}
-		return string(buf), nil
+		return Clean(string(buf)), nil
 	}
 	return targ[t0:], nil
 }
diff --git a/src/path/filepath/path_test.go b/src/path/filepath/path_test.go
index 7ea02a7c282378..efdb3c603592ee 100644
--- a/src/path/filepath/path_test.go
+++ b/src/path/filepath/path_test.go
@@ -1506,6 +1506,7 @@ var reltests = []RelTests{
 	{"/../../a/b", "/../../a/b/c/d", "c/d"},
 	{".", "a/b", "a/b"},
 	{".", "..", ".."},
+	{"", "../../.", "../.."},
 
 	// can't do purely lexically
 	{"..", ".", "err"},

From 4837fbe4145cd47b43eed66fee9eed9c2b988316 Mon Sep 17 00:00:00 2001
From: Sean Liao 
Date: Sun, 5 Oct 2025 23:09:03 +0100
Subject: [PATCH 105/229] net/http/httptest: check whether response bodies are
 allowed

Fixes #75471

Change-Id: Ie8fc5fae4b2a9285501198d8379bbffe51ee63f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/709335
Reviewed-by: Damien Neil 
Reviewed-by: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
---
 src/net/http/httptest/recorder.go      | 22 ++++++++++++++++++++++
 src/net/http/httptest/recorder_test.go | 16 ++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/src/net/http/httptest/recorder.go b/src/net/http/httptest/recorder.go
index 17aa70f06760a2..7890b5ef6bdf31 100644
--- a/src/net/http/httptest/recorder.go
+++ b/src/net/http/httptest/recorder.go
@@ -105,6 +105,10 @@ func (rw *ResponseRecorder) writeHeader(b []byte, str string) {
 // Write implements http.ResponseWriter. The data in buf is written to
 // rw.Body, if not nil.
 func (rw *ResponseRecorder) Write(buf []byte) (int, error) {
+	code := rw.Code
+	if !bodyAllowedForStatus(code) {
+		return 0, http.ErrBodyNotAllowed
+	}
 	rw.writeHeader(buf, "")
 	if rw.Body != nil {
 		rw.Body.Write(buf)
@@ -115,6 +119,10 @@ func (rw *ResponseRecorder) Write(buf []byte) (int, error) {
 // WriteString implements [io.StringWriter]. The data in str is written
 // to rw.Body, if not nil.
 func (rw *ResponseRecorder) WriteString(str string) (int, error) {
+	code := rw.Code
+	if !bodyAllowedForStatus(code) {
+		return 0, http.ErrBodyNotAllowed
+	}
 	rw.writeHeader(nil, str)
 	if rw.Body != nil {
 		rw.Body.WriteString(str)
@@ -122,6 +130,20 @@ func (rw *ResponseRecorder) WriteString(str string) (int, error) {
 	return len(str), nil
 }
 
+// bodyAllowedForStatus reports whether a given response status code
+// permits a body. See RFC 7230, section 3.3.
+func bodyAllowedForStatus(status int) bool {
+	switch {
+	case status >= 100 && status <= 199:
+		return false
+	case status == 204:
+		return false
+	case status == 304:
+		return false
+	}
+	return true
+}
+
 func checkWriteHeaderCode(code int) {
 	// Issue 22880: require valid WriteHeader status codes.
 	// For now we only enforce that it's three digits.
diff --git a/src/net/http/httptest/recorder_test.go b/src/net/http/httptest/recorder_test.go
index 4782eced43e6ce..abf8e118d6092e 100644
--- a/src/net/http/httptest/recorder_test.go
+++ b/src/net/http/httptest/recorder_test.go
@@ -5,6 +5,7 @@
 package httptest
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -309,6 +310,21 @@ func TestRecorder(t *testing.T) {
 	}
 }
 
+func TestBodyNotAllowed(t *testing.T) {
+	rw := NewRecorder()
+	rw.WriteHeader(204)
+
+	_, err := rw.Write([]byte("hello world"))
+	if !errors.Is(err, http.ErrBodyNotAllowed) {
+		t.Errorf("expected BodyNotAllowed for Write after 204, got: %v", err)
+	}
+
+	_, err = rw.WriteString("hello world")
+	if !errors.Is(err, http.ErrBodyNotAllowed) {
+		t.Errorf("expected BodyNotAllowed for WriteString after 204, got: %v", err)
+	}
+}
+
 // issue 39017 - disallow Content-Length values such as "+3"
 func TestParseContentLength(t *testing.T) {
 	tests := []struct {

From 0e466a8d1d89e15e953c7d35bcd9e02d3c89f62b Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Mon, 21 Jul 2025 13:30:08 -0400
Subject: [PATCH 106/229] cmd/compile: modify float-to-[u]int so that amd64 and
 arm64 match

Eventual goal is that all the architectures agree, and are
sensible.  The test will be build-tagged to exclude
not-yet-handled platforms.

This change also bisects the conversion change in case of bugs.
(`bisect -compile=convert ...`)

Change-Id: I98528666b0a3fde17cbe8d69b612d01da18dce85
Reviewed-on: https://go-review.googlesource.com/c/go/+/691135
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/internal/base/debug.go        |   1 +
 src/cmd/compile/internal/base/flag.go         |   3 +
 src/cmd/compile/internal/base/hashdebug.go    |   1 +
 src/cmd/compile/internal/ssa/_gen/AMD64.rules |  17 +-
 src/cmd/compile/internal/ssa/rewriteAMD64.go  | 197 ++++++++++++-
 src/cmd/compile/internal/ssagen/ssa.go        |  72 ++++-
 test/convert5.go                              | 268 ++++++++++++++++++
 test/convert5.out                             |  37 +++
 8 files changed, 569 insertions(+), 27 deletions(-)
 create mode 100644 test/convert5.go
 create mode 100644 test/convert5.out

diff --git a/src/cmd/compile/internal/base/debug.go b/src/cmd/compile/internal/base/debug.go
index 85873dcc40e1b3..9e8ab2f488bb4d 100644
--- a/src/cmd/compile/internal/base/debug.go
+++ b/src/cmd/compile/internal/base/debug.go
@@ -20,6 +20,7 @@ type DebugFlags struct {
 	Append                int    `help:"print information about append compilation"`
 	Checkptr              int    `help:"instrument unsafe pointer conversions\n0: instrumentation disabled\n1: conversions involving unsafe.Pointer are instrumented\n2: conversions to unsafe.Pointer force heap allocation" concurrent:"ok"`
 	Closure               int    `help:"print information about closure compilation"`
+	Converthash           string `help:"hash value for use in debugging changes to platform-dependent float-to-[u]int conversion" concurrent:"ok"`
 	Defer                 int    `help:"print information about defer compilation"`
 	DisableNil            int    `help:"disable nil checks" concurrent:"ok"`
 	DumpInlFuncProps      string `help:"dump function properties from inl heuristics to specified file"`
diff --git a/src/cmd/compile/internal/base/flag.go b/src/cmd/compile/internal/base/flag.go
index a0ed876cfc8e0e..1ac2cecc61ec7e 100644
--- a/src/cmd/compile/internal/base/flag.go
+++ b/src/cmd/compile/internal/base/flag.go
@@ -262,6 +262,9 @@ func ParseFlags() {
 		Debug.LoopVar = 1
 	}
 
+	if Debug.Converthash != "" {
+		ConvertHash = NewHashDebug("converthash", Debug.Converthash, nil)
+	}
 	if Debug.Fmahash != "" {
 		FmaHash = NewHashDebug("fmahash", Debug.Fmahash, nil)
 	}
diff --git a/src/cmd/compile/internal/base/hashdebug.go b/src/cmd/compile/internal/base/hashdebug.go
index fa63deb46a3c01..edf567457cb04b 100644
--- a/src/cmd/compile/internal/base/hashdebug.go
+++ b/src/cmd/compile/internal/base/hashdebug.go
@@ -53,6 +53,7 @@ func (d *HashDebug) SetInlineSuffixOnly(b bool) *HashDebug {
 // The default compiler-debugging HashDebug, for "-d=gossahash=..."
 var hashDebug *HashDebug
 
+var ConvertHash *HashDebug      // for debugging float-to-[u]int conversion changes
 var FmaHash *HashDebug          // for debugging fused-multiply-add floating point changes
 var LoopVarHash *HashDebug      // for debugging shared/private loop variable changes
 var PGOHash *HashDebug          // for debugging PGO optimization decisions
diff --git a/src/cmd/compile/internal/ssa/_gen/AMD64.rules b/src/cmd/compile/internal/ssa/_gen/AMD64.rules
index 7d3efef5cdc837..0bea99e38de1bc 100644
--- a/src/cmd/compile/internal/ssa/_gen/AMD64.rules
+++ b/src/cmd/compile/internal/ssa/_gen/AMD64.rules
@@ -162,10 +162,19 @@
 (Cvt64to32F ...) => (CVTSQ2SS ...)
 (Cvt64to64F ...) => (CVTSQ2SD ...)
 
-(Cvt32Fto32 ...) => (CVTTSS2SL ...)
-(Cvt32Fto64 ...) => (CVTTSS2SQ ...)
-(Cvt64Fto32 ...) => (CVTTSD2SL ...)
-(Cvt64Fto64 ...) => (CVTTSD2SQ ...)
+// Float, to int.
+// To make AMD64 "overflow" return max positive instead of max negative, compute
+// y and not x, smear the sign bit, and xor.
+(Cvt32Fto32  x) && base.ConvertHash.MatchPos(v.Pos, nil) => (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSS2SL  x) (NOTL  (MOVLf2i x)))))
+(Cvt64Fto32  x) && base.ConvertHash.MatchPos(v.Pos, nil) => (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSD2SL  x) (NOTL  (MOVLf2i (CVTSD2SS  x))))))
+
+(Cvt32Fto64  x) && base.ConvertHash.MatchPos(v.Pos, nil) => (XORQ  y (SARQconst  [63] (ANDQ  y:(CVTTSS2SQ  x) (NOTQ  (MOVQf2i (CVTSS2SD  x))) )))
+(Cvt64Fto64  x) && base.ConvertHash.MatchPos(v.Pos, nil) => (XORQ  y (SARQconst  [63] (ANDQ  y:(CVTTSD2SQ  x) (NOTQ  (MOVQf2i x)))))
+
+(Cvt32Fto32  x) && !base.ConvertHash.MatchPos(v.Pos, nil) => (CVTTSS2SL  x)
+(Cvt32Fto64  x) && !base.ConvertHash.MatchPos(v.Pos, nil) => (CVTTSS2SQ  x)
+(Cvt64Fto32  x) && !base.ConvertHash.MatchPos(v.Pos, nil) => (CVTTSD2SL  x)
+(Cvt64Fto64  x) && !base.ConvertHash.MatchPos(v.Pos, nil) => (CVTTSD2SQ  x)
 
 (Cvt32Fto64F ...) => (CVTSS2SD ...)
 (Cvt64Fto32F ...) => (CVTSD2SS ...)
diff --git a/src/cmd/compile/internal/ssa/rewriteAMD64.go b/src/cmd/compile/internal/ssa/rewriteAMD64.go
index a7ee632ae1af72..e702925f5f3bac 100644
--- a/src/cmd/compile/internal/ssa/rewriteAMD64.go
+++ b/src/cmd/compile/internal/ssa/rewriteAMD64.go
@@ -5,6 +5,7 @@ package ssa
 import "internal/buildcfg"
 import "math"
 import "cmd/internal/obj"
+import "cmd/compile/internal/base"
 import "cmd/compile/internal/types"
 
 func rewriteValueAMD64(v *Value) bool {
@@ -694,11 +695,9 @@ func rewriteValueAMD64(v *Value) bool {
 	case OpCtz8NonZero:
 		return rewriteValueAMD64_OpCtz8NonZero(v)
 	case OpCvt32Fto32:
-		v.Op = OpAMD64CVTTSS2SL
-		return true
+		return rewriteValueAMD64_OpCvt32Fto32(v)
 	case OpCvt32Fto64:
-		v.Op = OpAMD64CVTTSS2SQ
-		return true
+		return rewriteValueAMD64_OpCvt32Fto64(v)
 	case OpCvt32Fto64F:
 		v.Op = OpAMD64CVTSS2SD
 		return true
@@ -709,14 +708,12 @@ func rewriteValueAMD64(v *Value) bool {
 		v.Op = OpAMD64CVTSL2SD
 		return true
 	case OpCvt64Fto32:
-		v.Op = OpAMD64CVTTSD2SL
-		return true
+		return rewriteValueAMD64_OpCvt64Fto32(v)
 	case OpCvt64Fto32F:
 		v.Op = OpAMD64CVTSD2SS
 		return true
 	case OpCvt64Fto64:
-		v.Op = OpAMD64CVTTSD2SQ
-		return true
+		return rewriteValueAMD64_OpCvt64Fto64(v)
 	case OpCvt64to32F:
 		v.Op = OpAMD64CVTSQ2SS
 		return true
@@ -25511,6 +25508,190 @@ func rewriteValueAMD64_OpCtz8NonZero(v *Value) bool {
 	}
 	return false
 }
+func rewriteValueAMD64_OpCvt32Fto32(v *Value) bool {
+	v_0 := v.Args[0]
+	b := v.Block
+	typ := &b.Func.Config.Types
+	// match: (Cvt32Fto32  x)
+	// cond: base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSS2SL  x) (NOTL  (MOVLf2i x)))))
+	for {
+		t := v.Type
+		x := v_0
+		if !(base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(OpAMD64XORL)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, OpAMD64SARLconst, t)
+		v0.AuxInt = int8ToAuxInt(31)
+		v1 := b.NewValue0(v.Pos, OpAMD64ANDL, t)
+		y := b.NewValue0(v.Pos, OpAMD64CVTTSS2SL, t)
+		y.AddArg(x)
+		v3 := b.NewValue0(v.Pos, OpAMD64NOTL, typ.Int32)
+		v4 := b.NewValue0(v.Pos, OpAMD64MOVLf2i, typ.UInt32)
+		v4.AddArg(x)
+		v3.AddArg(v4)
+		v1.AddArg2(y, v3)
+		v0.AddArg(v1)
+		v.AddArg2(y, v0)
+		return true
+	}
+	// match: (Cvt32Fto32  x)
+	// cond: !base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (CVTTSS2SL  x)
+	for {
+		t := v.Type
+		x := v_0
+		if !(!base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(OpAMD64CVTTSS2SL)
+		v.Type = t
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
+func rewriteValueAMD64_OpCvt32Fto64(v *Value) bool {
+	v_0 := v.Args[0]
+	b := v.Block
+	typ := &b.Func.Config.Types
+	// match: (Cvt32Fto64  x)
+	// cond: base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (XORQ  y (SARQconst  [63] (ANDQ  y:(CVTTSS2SQ  x) (NOTQ  (MOVQf2i (CVTSS2SD  x))) )))
+	for {
+		t := v.Type
+		x := v_0
+		if !(base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(OpAMD64XORQ)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, OpAMD64SARQconst, t)
+		v0.AuxInt = int8ToAuxInt(63)
+		v1 := b.NewValue0(v.Pos, OpAMD64ANDQ, t)
+		y := b.NewValue0(v.Pos, OpAMD64CVTTSS2SQ, t)
+		y.AddArg(x)
+		v3 := b.NewValue0(v.Pos, OpAMD64NOTQ, typ.Int64)
+		v4 := b.NewValue0(v.Pos, OpAMD64MOVQf2i, typ.UInt64)
+		v5 := b.NewValue0(v.Pos, OpAMD64CVTSS2SD, typ.Float64)
+		v5.AddArg(x)
+		v4.AddArg(v5)
+		v3.AddArg(v4)
+		v1.AddArg2(y, v3)
+		v0.AddArg(v1)
+		v.AddArg2(y, v0)
+		return true
+	}
+	// match: (Cvt32Fto64  x)
+	// cond: !base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (CVTTSS2SQ  x)
+	for {
+		t := v.Type
+		x := v_0
+		if !(!base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(OpAMD64CVTTSS2SQ)
+		v.Type = t
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
+func rewriteValueAMD64_OpCvt64Fto32(v *Value) bool {
+	v_0 := v.Args[0]
+	b := v.Block
+	typ := &b.Func.Config.Types
+	// match: (Cvt64Fto32  x)
+	// cond: base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSD2SL  x) (NOTL  (MOVLf2i (CVTSD2SS  x))))))
+	for {
+		t := v.Type
+		x := v_0
+		if !(base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(OpAMD64XORL)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, OpAMD64SARLconst, t)
+		v0.AuxInt = int8ToAuxInt(31)
+		v1 := b.NewValue0(v.Pos, OpAMD64ANDL, t)
+		y := b.NewValue0(v.Pos, OpAMD64CVTTSD2SL, t)
+		y.AddArg(x)
+		v3 := b.NewValue0(v.Pos, OpAMD64NOTL, typ.Int32)
+		v4 := b.NewValue0(v.Pos, OpAMD64MOVLf2i, typ.UInt32)
+		v5 := b.NewValue0(v.Pos, OpAMD64CVTSD2SS, typ.Float32)
+		v5.AddArg(x)
+		v4.AddArg(v5)
+		v3.AddArg(v4)
+		v1.AddArg2(y, v3)
+		v0.AddArg(v1)
+		v.AddArg2(y, v0)
+		return true
+	}
+	// match: (Cvt64Fto32  x)
+	// cond: !base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (CVTTSD2SL  x)
+	for {
+		t := v.Type
+		x := v_0
+		if !(!base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(OpAMD64CVTTSD2SL)
+		v.Type = t
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
+func rewriteValueAMD64_OpCvt64Fto64(v *Value) bool {
+	v_0 := v.Args[0]
+	b := v.Block
+	typ := &b.Func.Config.Types
+	// match: (Cvt64Fto64  x)
+	// cond: base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (XORQ  y (SARQconst  [63] (ANDQ  y:(CVTTSD2SQ  x) (NOTQ  (MOVQf2i x)))))
+	for {
+		t := v.Type
+		x := v_0
+		if !(base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(OpAMD64XORQ)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, OpAMD64SARQconst, t)
+		v0.AuxInt = int8ToAuxInt(63)
+		v1 := b.NewValue0(v.Pos, OpAMD64ANDQ, t)
+		y := b.NewValue0(v.Pos, OpAMD64CVTTSD2SQ, t)
+		y.AddArg(x)
+		v3 := b.NewValue0(v.Pos, OpAMD64NOTQ, typ.Int64)
+		v4 := b.NewValue0(v.Pos, OpAMD64MOVQf2i, typ.UInt64)
+		v4.AddArg(x)
+		v3.AddArg(v4)
+		v1.AddArg2(y, v3)
+		v0.AddArg(v1)
+		v.AddArg2(y, v0)
+		return true
+	}
+	// match: (Cvt64Fto64  x)
+	// cond: !base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (CVTTSD2SQ  x)
+	for {
+		t := v.Type
+		x := v_0
+		if !(!base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(OpAMD64CVTTSD2SQ)
+		v.Type = t
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
 func rewriteValueAMD64_OpDiv16(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 6c4afb78959791..2705195bd55791 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -2574,13 +2574,13 @@ var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
 
 	{types.TFLOAT32, types.TUINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
 	{types.TFLOAT32, types.TUINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
-	{types.TFLOAT32, types.TUINT32}: {ssa.OpCvt32Fto64, ssa.OpTrunc64to32, types.TINT64}, // go wide to dodge unsigned
-	{types.TFLOAT32, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64},          // Cvt32Fto64U, branchy code expansion instead
+	{types.TFLOAT32, types.TUINT32}: {ssa.OpInvalid, ssa.OpCopy, types.TINT64},  // Cvt64Fto32U, branchy code expansion instead
+	{types.TFLOAT32, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64}, // Cvt32Fto64U, branchy code expansion instead
 
 	{types.TFLOAT64, types.TUINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
 	{types.TFLOAT64, types.TUINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
-	{types.TFLOAT64, types.TUINT32}: {ssa.OpCvt64Fto64, ssa.OpTrunc64to32, types.TINT64}, // go wide to dodge unsigned
-	{types.TFLOAT64, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64},          // Cvt64Fto64U, branchy code expansion instead
+	{types.TFLOAT64, types.TUINT32}: {ssa.OpInvalid, ssa.OpCopy, types.TINT64},  // Cvt64Fto32U, branchy code expansion instead
+	{types.TFLOAT64, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64}, // Cvt64Fto64U, branchy code expansion instead
 
 	// float
 	{types.TFLOAT64, types.TFLOAT32}: {ssa.OpCvt64Fto32F, ssa.OpCopy, types.TFLOAT32},
@@ -2860,10 +2860,23 @@ func (s *state) conv(n ir.Node, v *ssa.Value, ft, tt *types.Type) *ssa.Value {
 		}
 		// ft is float32 or float64, and tt is unsigned integer
 		if ft.Size() == 4 {
-			return s.float32ToUint64(n, v, ft, tt)
+			switch tt.Size() {
+			case 8:
+				return s.float32ToUint64(n, v, ft, tt)
+			case 4, 2, 1:
+				// TODO should 2 and 1 saturate or truncate?
+				return s.float32ToUint32(n, v, ft, tt)
+			}
 		}
 		if ft.Size() == 8 {
-			return s.float64ToUint64(n, v, ft, tt)
+			switch tt.Size() {
+			case 8:
+				return s.float64ToUint64(n, v, ft, tt)
+			case 4, 2, 1:
+				// TODO should 2 and 1 saturate or truncate?
+				return s.float64ToUint32(n, v, ft, tt)
+			}
+
 		}
 		s.Fatalf("weird float to unsigned integer conversion %v -> %v", ft, tt)
 		return nil
@@ -5553,7 +5566,9 @@ func (s *state) uint64Tofloat(cvttab *u642fcvtTab, n ir.Node, x *ssa.Value, ft,
 	// equal to 10000000001; that rounds up, and the 1 cannot
 	// be lost else it would round down if the LSB of the
 	// candidate mantissa is 0.
+
 	cmp := s.newValue2(cvttab.leq, types.Types[types.TBOOL], s.zeroVal(ft), x)
+
 	b := s.endBlock()
 	b.Kind = ssa.BlockIf
 	b.SetControl(cmp)
@@ -5779,34 +5794,61 @@ func (s *state) float64ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ss
 func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
 	// cutoff:=1<<(intY_Size-1)
 	// if x < floatX(cutoff) {
-	// 	result = uintY(x)
+	// 	result = uintY(x) // bThen
+	// 	if x < 0 { // unlikely
+	// 		result = 0 // bZero
+	// 	}
 	// } else {
-	// 	y = x - floatX(cutoff)
+	// 	y = x - floatX(cutoff) // bElse
 	// 	z = uintY(y)
 	// 	result = z | -(cutoff)
 	// }
+
 	cutoff := cvttab.floatValue(s, ft, float64(cvttab.cutoff))
-	cmp := s.newValue2(cvttab.ltf, types.Types[types.TBOOL], x, cutoff)
+	cmp := s.newValueOrSfCall2(cvttab.ltf, types.Types[types.TBOOL], x, cutoff)
 	b := s.endBlock()
 	b.Kind = ssa.BlockIf
 	b.SetControl(cmp)
 	b.Likely = ssa.BranchLikely
 
-	bThen := s.f.NewBlock(ssa.BlockPlain)
+	var bThen, bZero *ssa.Block
+	newConversion := base.ConvertHash.MatchPos(n.Pos(), nil)
+	if newConversion {
+		bZero = s.f.NewBlock(ssa.BlockPlain)
+		bThen = s.f.NewBlock(ssa.BlockIf)
+	} else {
+		bThen = s.f.NewBlock(ssa.BlockPlain)
+	}
+
 	bElse := s.f.NewBlock(ssa.BlockPlain)
 	bAfter := s.f.NewBlock(ssa.BlockPlain)
 
 	b.AddEdgeTo(bThen)
 	s.startBlock(bThen)
-	a0 := s.newValue1(cvttab.cvt2U, tt, x)
+	a0 := s.newValueOrSfCall1(cvttab.cvt2U, tt, x)
 	s.vars[n] = a0
-	s.endBlock()
-	bThen.AddEdgeTo(bAfter)
+
+	if newConversion {
+		cmpz := s.newValueOrSfCall2(cvttab.ltf, types.Types[types.TBOOL], x, cvttab.floatValue(s, ft, 0.0))
+		s.endBlock()
+		bThen.SetControl(cmpz)
+		bThen.AddEdgeTo(bZero)
+		bThen.Likely = ssa.BranchUnlikely
+		bThen.AddEdgeTo(bAfter)
+
+		s.startBlock(bZero)
+		s.vars[n] = cvttab.intValue(s, tt, 0)
+		s.endBlock()
+		bZero.AddEdgeTo(bAfter)
+	} else {
+		s.endBlock()
+		bThen.AddEdgeTo(bAfter)
+	}
 
 	b.AddEdgeTo(bElse)
 	s.startBlock(bElse)
-	y := s.newValue2(cvttab.subf, ft, x, cutoff)
-	y = s.newValue1(cvttab.cvt2U, tt, y)
+	y := s.newValueOrSfCall2(cvttab.subf, ft, x, cutoff)
+	y = s.newValueOrSfCall1(cvttab.cvt2U, tt, y)
 	z := cvttab.intValue(s, tt, int64(-cvttab.cutoff))
 	a1 := s.newValue2(cvttab.or, tt, y, z)
 	s.vars[n] = a1
diff --git a/test/convert5.go b/test/convert5.go
new file mode 100644
index 00000000000000..1bd74abdad0715
--- /dev/null
+++ b/test/convert5.go
@@ -0,0 +1,268 @@
+// run
+
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !wasm && !386 && !arm && !mips
+
+// TODO fix this to work for wasm and 32-bit architectures.
+// Doing more than this, however, expands the change.
+
+package main
+
+import (
+	"fmt"
+	"runtime"
+)
+
+// This test checks that conversion from floats to (unsigned) 32 and 64-bit
+// integers has the same sensible behavior for corner cases, and that the
+// conversions to smaller integers agree.  Because outliers are platform-
+// independent, the "golden test" for smaller integers is more like of
+// a "gold-ish test" and subject to change.
+
+//go:noinline
+func id[T any](x T) T {
+	return x
+}
+
+//go:noinline
+func want[T comparable](name string, x, y T) {
+	if x != y {
+		_, _, line, _ := runtime.Caller(1)
+		fmt.Println("FAIL at line", line, "var =", name, "got =", x, "want =", y)
+	}
+}
+
+//go:noinline
+func log[T comparable](name string, x T) {
+	fmt.Println(name, x)
+}
+
+const (
+	// pX = max positive signed X bit
+	// nX = min negative signed X bit
+	// uX = max unsigned X bit
+	// tX = two to the X
+	p32 = 2147483647
+	n32 = -2147483648
+	u32 = 4294967295
+	p64 = 9223372036854775807
+	n64 = -9223372036854775808
+	u64 = 18446744073709551615
+	t44 = 1 << 44
+)
+
+func main() {
+	one := 1.0
+	minus1_32 := id(float32(-1.0))
+	minus1_64 := id(float64(-1.0))
+	p32_plus4k_plus1 := id(float32(p32 + 4096 + 1)) // want this to be precise and fit in 24 bits mantissa
+	p64_plus4k_plus1 := id(float64(p64 + 4096 + 1)) // want this to be precise and fit in 53 bits mantissa
+	n32_minus4k := id(float32(n32 - 4096))
+	n64_minus4k := id(float64(n64 - 4096))
+	inf_32 := id(float32(one / 0))
+	inf_64 := id(float64(one / 0))
+	ninf_32 := id(float32(-one / 0))
+	ninf_64 := id(float64(-one / 0))
+
+	// int32 conversions
+	int32Tests := []struct {
+		name     string
+		input    any // Use any to handle both float32 and float64
+		expected int32
+	}{
+		{"minus1_32", minus1_32, -1},
+		{"minus1_64", minus1_64, -1},
+		{"p32_plus4k_plus1", p32_plus4k_plus1, p32},
+		{"p64_plus4k_plus1", p64_plus4k_plus1, p32},
+		{"n32_minus4k", n32_minus4k, n32},
+		{"n64_minus4k", n64_minus4k, n32},
+		{"inf_32", inf_32, p32},
+		{"inf_64", inf_64, p32},
+		{"ninf_32", ninf_32, n32},
+		{"ninf_64", ninf_64, n32},
+	}
+
+	for _, test := range int32Tests {
+		var converted int32
+		switch v := test.input.(type) {
+		case float32:
+			converted = int32(v)
+		case float64:
+			converted = int32(v)
+		}
+		want(test.name, converted, test.expected)
+	}
+
+	// int64 conversions
+	int64Tests := []struct {
+		name     string
+		input    any
+		expected int64
+	}{
+		{"minus1_32", minus1_32, -1},
+		{"minus1_64", minus1_64, -1},
+		{"p32_plus4k_plus1", p32_plus4k_plus1, p32 + 4096 + 1},
+		{"p64_plus4k_plus1", p64_plus4k_plus1, p64},
+		{"n32_minus4k", n32_minus4k, n32 - 4096},
+		{"n64_minus4k", n64_minus4k, n64},
+		{"inf_32", inf_32, p64},
+		{"inf_64", inf_64, p64},
+		{"ninf_32", ninf_32, n64},
+		{"ninf_64", ninf_64, n64},
+	}
+
+	for _, test := range int64Tests {
+		var converted int64
+		switch v := test.input.(type) {
+		case float32:
+			converted = int64(v)
+		case float64:
+			converted = int64(v)
+		}
+		want(test.name, converted, test.expected)
+	}
+
+	// uint32 conversions
+	uint32Tests := []struct {
+		name     string
+		input    any
+		expected uint32
+	}{
+		{"minus1_32", minus1_32, 0},
+		{"minus1_64", minus1_64, 0},
+		{"p32_plus4k_plus1", p32_plus4k_plus1, p32 + 4096 + 1},
+		{"p64_plus4k_plus1", p64_plus4k_plus1, u32},
+		{"n32_minus4k", n32_minus4k, 0},
+		{"n64_minus4k", n64_minus4k, 0},
+		{"inf_32", inf_32, u32},
+		{"inf_64", inf_64, u32},
+		{"ninf_32", ninf_32, 0},
+		{"ninf_64", ninf_64, 0},
+	}
+
+	for _, test := range uint32Tests {
+		var converted uint32
+		switch v := test.input.(type) {
+		case float32:
+			converted = uint32(v)
+		case float64:
+			converted = uint32(v)
+		}
+		want(test.name, converted, test.expected)
+	}
+
+	u64_plus4k_plus1_64 := id(float64(u64 + 4096 + 1))
+	u64_plust44_plus1_32 := id(float32(u64 + t44 + 1))
+
+	// uint64 conversions
+	uint64Tests := []struct {
+		name     string
+		input    any
+		expected uint64
+	}{
+		{"minus1_32", minus1_32, 0},
+		{"minus1_64", minus1_64, 0},
+		{"p32_plus4k_plus1", p32_plus4k_plus1, p32 + 4096 + 1},
+		{"p64_plus4k_plus1", p64_plus4k_plus1, p64 + 4096 + 1},
+		{"n32_minus4k", n32_minus4k, 0},
+		{"n64_minus4k", n64_minus4k, 0},
+		{"inf_32", inf_32, u64},
+		{"inf_64", inf_64, u64},
+		{"ninf_32", ninf_32, 0},
+		{"ninf_64", ninf_64, 0},
+		{"u64_plus4k_plus1_64", u64_plus4k_plus1_64, u64},
+		{"u64_plust44_plus1_32", u64_plust44_plus1_32, u64},
+	}
+
+	for _, test := range uint64Tests {
+		var converted uint64
+		switch v := test.input.(type) {
+		case float32:
+			converted = uint64(v)
+		case float64:
+			converted = uint64(v)
+		}
+		want(test.name, converted, test.expected)
+	}
+
+	// for smaller integer types
+	// TODO the overflow behavior is dubious, maybe we should fix it to be more sensible, e.g. saturating.
+	fmt.Println("Below this are 'golden' results to check for consistency across platforms.  Overflow behavior is not necessarily what we want")
+
+	u8plus2 := id(float64(257))
+	p8minus1 := id(float32(126))
+	n8plus2 := id(float64(-126))
+	n8minusone := id(float32(-129))
+
+	fmt.Println("\nuint8 conversions")
+	uint8Tests := []struct {
+		name  string
+		input any
+	}{
+		{"minus1_32", minus1_32},
+		{"minus1_64", minus1_64},
+		{"p32_plus4k_plus1", p32_plus4k_plus1},
+		{"p64_plus4k_plus1", p64_plus4k_plus1},
+		{"n32_minus4k", n32_minus4k},
+		{"n64_minus4k", n64_minus4k},
+		{"inf_32", inf_32},
+		{"inf_64", inf_64},
+		{"ninf_32", ninf_32},
+		{"ninf_64", ninf_64},
+		{"u64_plus4k_plus1_64", u64_plus4k_plus1_64},
+		{"u64_plust44_plus1_32", u64_plust44_plus1_32},
+		{"u8plus2", u8plus2},
+		{"p8minus1", p8minus1},
+		{"n8plus2", n8plus2},
+		{"n8minusone", n8minusone},
+	}
+
+	for _, test := range uint8Tests {
+		var converted uint8
+		switch v := test.input.(type) {
+		case float32:
+			converted = uint8(v)
+		case float64:
+			converted = uint8(v)
+		}
+		log(test.name, converted)
+	}
+
+	fmt.Println("\nint8 conversions")
+	int8Tests := []struct {
+		name  string
+		input any
+	}{
+		{"minus1_32", minus1_32},
+		{"minus1_64", minus1_64},
+		{"p32_plus4k_plus1", p32_plus4k_plus1},
+		{"p64_plus4k_plus1", p64_plus4k_plus1},
+		{"n32_minus4k", n32_minus4k},
+		{"n64_minus4k", n64_minus4k},
+		{"inf_32", inf_32},
+		{"inf_64", inf_64},
+		{"ninf_32", ninf_32},
+		{"ninf_64", ninf_64},
+		{"u64_plus4k_plus1_64", u64_plus4k_plus1_64},
+		{"u64_plust44_plus1_32", u64_plust44_plus1_32},
+		{"u8plus2", u8plus2},
+		{"p8minus1", p8minus1},
+		{"n8plus2", n8plus2},
+		{"n8minusone", n8minusone},
+	}
+
+	for _, test := range int8Tests {
+		var converted int8
+		switch v := test.input.(type) {
+		case float32:
+			converted = int8(v)
+		case float64:
+			converted = int8(v)
+		}
+		log(test.name, converted)
+	}
+
+}
diff --git a/test/convert5.out b/test/convert5.out
new file mode 100644
index 00000000000000..47a8af67f961f2
--- /dev/null
+++ b/test/convert5.out
@@ -0,0 +1,37 @@
+Below this are 'golden' results to check for consistency across platforms.  Overflow behavior is not necessarily what we want
+
+uint8 conversions
+minus1_32 255
+minus1_64 255
+p32_plus4k_plus1 255
+p64_plus4k_plus1 255
+n32_minus4k 0
+n64_minus4k 0
+inf_32 255
+inf_64 255
+ninf_32 0
+ninf_64 0
+u64_plus4k_plus1_64 255
+u64_plust44_plus1_32 255
+u8plus2 1
+p8minus1 126
+n8plus2 130
+n8minusone 127
+
+int8 conversions
+minus1_32 -1
+minus1_64 -1
+p32_plus4k_plus1 -1
+p64_plus4k_plus1 -1
+n32_minus4k 0
+n64_minus4k 0
+inf_32 -1
+inf_64 -1
+ninf_32 0
+ninf_64 0
+u64_plus4k_plus1_64 -1
+u64_plust44_plus1_32 -1
+u8plus2 1
+p8minus1 126
+n8plus2 -126
+n8minusone 127

From 78d75b37992be01326b9bd2666195aaba9bf2ae2 Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Tue, 30 Sep 2025 16:27:32 -0400
Subject: [PATCH 107/229] cmd/compile: make 386 float-to-int conversions match
 amd64

Change-Id: Iff13b4471f94a6a91d8b159603a9338cb9c89747
Reviewed-on: https://go-review.googlesource.com/c/go/+/708295
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/compile/internal/ssa/_gen/386.rules |  6 +-
 src/cmd/compile/internal/ssa/_gen/386Ops.go |  2 +
 src/cmd/compile/internal/ssa/opGen.go       | 13 +++
 src/cmd/compile/internal/ssa/rewrite386.go  | 99 ++++++++++++++++++++-
 src/cmd/compile/internal/x86/ssa.go         |  7 ++
 src/runtime/asm_386.s                       | 10 ---
 src/runtime/stubs_386.go                    |  1 -
 src/runtime/vlrt.go                         | 63 ++++++++++++-
 test/convert5.go                            |  4 +-
 9 files changed, 182 insertions(+), 23 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/_gen/386.rules b/src/cmd/compile/internal/ssa/_gen/386.rules
index 5f1150241929eb..4e3d3203c79041 100644
--- a/src/cmd/compile/internal/ssa/_gen/386.rules
+++ b/src/cmd/compile/internal/ssa/_gen/386.rules
@@ -88,8 +88,10 @@
 (Cvt32to32F ...) => (CVTSL2SS ...)
 (Cvt32to64F ...) => (CVTSL2SD ...)
 
-(Cvt32Fto32 ...) => (CVTTSS2SL ...)
-(Cvt64Fto32 ...) => (CVTTSD2SL ...)
+(Cvt32Fto32  x) && base.ConvertHash.MatchPos(v.Pos, nil) => (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSS2SL  x) (NOTL  (MOVLf2i x)))))
+(Cvt64Fto32  x) && base.ConvertHash.MatchPos(v.Pos, nil) => (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSD2SL  x) (NOTL  (MOVLf2i (CVTSD2SS  x))))))
+(Cvt32Fto32  x) && !base.ConvertHash.MatchPos(v.Pos, nil) => (CVTTSS2SL  x)
+(Cvt64Fto32  x) && !base.ConvertHash.MatchPos(v.Pos, nil) => (CVTTSD2SL  x)
 
 (Cvt32Fto64F ...) => (CVTSS2SD ...)
 (Cvt64Fto32F ...) => (CVTSD2SS ...)
diff --git a/src/cmd/compile/internal/ssa/_gen/386Ops.go b/src/cmd/compile/internal/ssa/_gen/386Ops.go
index 60599a33abb587..86c2f9c8f080f8 100644
--- a/src/cmd/compile/internal/ssa/_gen/386Ops.go
+++ b/src/cmd/compile/internal/ssa/_gen/386Ops.go
@@ -342,6 +342,8 @@ func init() {
 		{name: "MOVWLSX", argLength: 1, reg: gp11, asm: "MOVWLSX"}, // sign extend arg0 from int16 to int32
 		{name: "MOVWLZX", argLength: 1, reg: gp11, asm: "MOVWLZX"}, // zero extend arg0 from int16 to int32
 
+		{name: "MOVLf2i", argLength: 1, reg: fpgp, typ: "UInt32"}, // move 32 bits from float to int reg, zero extend
+
 		{name: "MOVLconst", reg: gp01, asm: "MOVL", typ: "UInt32", aux: "Int32", rematerializeable: true}, // 32 low bits of auxint
 
 		{name: "CVTTSD2SL", argLength: 1, reg: fpgp, asm: "CVTTSD2SL"}, // convert float64 to int32
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 92adf5341b2574..2a60398bc68711 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -499,6 +499,7 @@ const (
 	Op386MOVBLZX
 	Op386MOVWLSX
 	Op386MOVWLZX
+	Op386MOVLf2i
 	Op386MOVLconst
 	Op386CVTTSD2SL
 	Op386CVTTSS2SL
@@ -5601,6 +5602,18 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
+	{
+		name:   "MOVLf2i",
+		argLen: 1,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 65280}, // X0 X1 X2 X3 X4 X5 X6 X7
+			},
+			outputs: []outputInfo{
+				{0, 239}, // AX CX DX BX BP SI DI
+			},
+		},
+	},
 	{
 		name:              "MOVLconst",
 		auxType:           auxInt32,
diff --git a/src/cmd/compile/internal/ssa/rewrite386.go b/src/cmd/compile/internal/ssa/rewrite386.go
index 0495438710659e..4845f1e0250ea8 100644
--- a/src/cmd/compile/internal/ssa/rewrite386.go
+++ b/src/cmd/compile/internal/ssa/rewrite386.go
@@ -3,6 +3,7 @@
 package ssa
 
 import "math"
+import "cmd/compile/internal/base"
 import "cmd/compile/internal/types"
 
 func rewriteValue386(v *Value) bool {
@@ -340,8 +341,7 @@ func rewriteValue386(v *Value) bool {
 		v.Op = Op386BSFL
 		return true
 	case OpCvt32Fto32:
-		v.Op = Op386CVTTSS2SL
-		return true
+		return rewriteValue386_OpCvt32Fto32(v)
 	case OpCvt32Fto64F:
 		v.Op = Op386CVTSS2SD
 		return true
@@ -352,8 +352,7 @@ func rewriteValue386(v *Value) bool {
 		v.Op = Op386CVTSL2SD
 		return true
 	case OpCvt64Fto32:
-		v.Op = Op386CVTTSD2SL
-		return true
+		return rewriteValue386_OpCvt64Fto32(v)
 	case OpCvt64Fto32F:
 		v.Op = Op386CVTSD2SS
 		return true
@@ -7964,6 +7963,98 @@ func rewriteValue386_OpCtz8(v *Value) bool {
 		return true
 	}
 }
+func rewriteValue386_OpCvt32Fto32(v *Value) bool {
+	v_0 := v.Args[0]
+	b := v.Block
+	typ := &b.Func.Config.Types
+	// match: (Cvt32Fto32  x)
+	// cond: base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSS2SL  x) (NOTL  (MOVLf2i x)))))
+	for {
+		t := v.Type
+		x := v_0
+		if !(base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(Op386XORL)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, Op386SARLconst, t)
+		v0.AuxInt = int32ToAuxInt(31)
+		v1 := b.NewValue0(v.Pos, Op386ANDL, t)
+		y := b.NewValue0(v.Pos, Op386CVTTSS2SL, t)
+		y.AddArg(x)
+		v3 := b.NewValue0(v.Pos, Op386NOTL, typ.Int32)
+		v4 := b.NewValue0(v.Pos, Op386MOVLf2i, typ.UInt32)
+		v4.AddArg(x)
+		v3.AddArg(v4)
+		v1.AddArg2(y, v3)
+		v0.AddArg(v1)
+		v.AddArg2(y, v0)
+		return true
+	}
+	// match: (Cvt32Fto32  x)
+	// cond: !base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (CVTTSS2SL  x)
+	for {
+		t := v.Type
+		x := v_0
+		if !(!base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(Op386CVTTSS2SL)
+		v.Type = t
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
+func rewriteValue386_OpCvt64Fto32(v *Value) bool {
+	v_0 := v.Args[0]
+	b := v.Block
+	typ := &b.Func.Config.Types
+	// match: (Cvt64Fto32  x)
+	// cond: base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSD2SL  x) (NOTL  (MOVLf2i (CVTSD2SS  x))))))
+	for {
+		t := v.Type
+		x := v_0
+		if !(base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(Op386XORL)
+		v.Type = t
+		v0 := b.NewValue0(v.Pos, Op386SARLconst, t)
+		v0.AuxInt = int32ToAuxInt(31)
+		v1 := b.NewValue0(v.Pos, Op386ANDL, t)
+		y := b.NewValue0(v.Pos, Op386CVTTSD2SL, t)
+		y.AddArg(x)
+		v3 := b.NewValue0(v.Pos, Op386NOTL, typ.Int32)
+		v4 := b.NewValue0(v.Pos, Op386MOVLf2i, typ.UInt32)
+		v5 := b.NewValue0(v.Pos, Op386CVTSD2SS, typ.Float32)
+		v5.AddArg(x)
+		v4.AddArg(v5)
+		v3.AddArg(v4)
+		v1.AddArg2(y, v3)
+		v0.AddArg(v1)
+		v.AddArg2(y, v0)
+		return true
+	}
+	// match: (Cvt64Fto32  x)
+	// cond: !base.ConvertHash.MatchPos(v.Pos, nil)
+	// result: (CVTTSD2SL  x)
+	for {
+		t := v.Type
+		x := v_0
+		if !(!base.ConvertHash.MatchPos(v.Pos, nil)) {
+			break
+		}
+		v.reset(Op386CVTTSD2SL)
+		v.Type = t
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
 func rewriteValue386_OpDiv8(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
diff --git a/src/cmd/compile/internal/x86/ssa.go b/src/cmd/compile/internal/x86/ssa.go
index d0aad088496351..2858a81b4b977b 100644
--- a/src/cmd/compile/internal/x86/ssa.go
+++ b/src/cmd/compile/internal/x86/ssa.go
@@ -538,6 +538,13 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.To.Type = obj.TYPE_MEM
 		p.To.Reg = v.Args[0].Reg()
 		ssagen.AddAux(&p.To, v)
+	case ssa.Op386MOVLf2i:
+		var p *obj.Prog
+		p = s.Prog(x86.AMOVL)
+		p.From.Type = obj.TYPE_REG
+		p.From.Reg = v.Args[0].Reg()
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = v.Reg()
 	case ssa.Op386ADDLconstmodify:
 		sc := v.AuxValAndOff()
 		val := sc.Val()
diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index df32e90fda8416..2a6de64f9fbdb3 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -1407,16 +1407,6 @@ TEXT runtime·uint32tofloat64(SB),NOSPLIT,$8-12
 	FMOVDP	F0, ret+4(FP)
 	RET
 
-TEXT runtime·float64touint32(SB),NOSPLIT,$12-12
-	FMOVD	a+0(FP), F0
-	FSTCW	0(SP)
-	FLDCW	runtime·controlWord64trunc(SB)
-	FMOVVP	F0, 4(SP)
-	FLDCW	0(SP)
-	MOVL	4(SP), AX
-	MOVL	AX, ret+8(FP)
-	RET
-
 // gcWriteBarrier informs the GC about heap pointer writes.
 //
 // gcWriteBarrier returns space in a write barrier buffer which
diff --git a/src/runtime/stubs_386.go b/src/runtime/stubs_386.go
index a1dd023974a0c6..4f3dcd4fd9b250 100644
--- a/src/runtime/stubs_386.go
+++ b/src/runtime/stubs_386.go
@@ -6,7 +6,6 @@ package runtime
 
 import "unsafe"
 
-func float64touint32(a float64) uint32
 func uint32tofloat64(a uint32) float64
 
 // stackcheck checks that SP is in range [g->stack.lo, g->stack.hi).
diff --git a/src/runtime/vlrt.go b/src/runtime/vlrt.go
index 4b12f593c8a8ec..511eb0dd4edf40 100644
--- a/src/runtime/vlrt.go
+++ b/src/runtime/vlrt.go
@@ -40,10 +40,17 @@ func float64toint64(d float64) (y uint64) {
 }
 
 func float64touint64(d float64) (y uint64) {
-	_d2v(&y, d)
+	_d2vu(&y, d)
 	return
 }
 
+func float64touint32(a float64) uint32 {
+	if a >= 0xffffffff {
+		return 0xffffffff
+	}
+	return uint32(float64touint64(a))
+}
+
 func int64tofloat64(y int64) float64 {
 	if y < 0 {
 		return -uint64tofloat64(-uint64(y))
@@ -117,12 +124,16 @@ func _d2v(y *uint64, d float64) {
 	} else {
 		/* v = (hi||lo) << -sh */
 		sh := uint32(-sh)
-		if sh <= 11 {
+		if sh <= 10 {
 			ylo = xlo << sh
 			yhi = xhi<>(32-sh)
 		} else {
-			/* overflow */
-			yhi = uint32(d) /* causes something awful */
+			if x&sign64 != 0 {
+				*y = 0x8000000000000000
+			} else {
+				*y = 0x7fffffffffffffff
+			}
+			return
 		}
 	}
 	if x&sign64 != 0 {
@@ -136,6 +147,50 @@ func _d2v(y *uint64, d float64) {
 
 	*y = uint64(yhi)<<32 | uint64(ylo)
 }
+func _d2vu(y *uint64, d float64) {
+	x := *(*uint64)(unsafe.Pointer(&d))
+	if x&sign64 != 0 {
+		*y = 0
+		return
+	}
+
+	xhi := uint32(x>>32)&0xfffff | 0x100000
+	xlo := uint32(x)
+	sh := 1075 - int32(uint32(x>>52)&0x7ff)
+
+	var ylo, yhi uint32
+	if sh >= 0 {
+		sh := uint32(sh)
+		/* v = (hi||lo) >> sh */
+		if sh < 32 {
+			if sh == 0 {
+				ylo = xlo
+				yhi = xhi
+			} else {
+				ylo = xlo>>sh | xhi<<(32-sh)
+				yhi = xhi >> sh
+			}
+		} else {
+			if sh == 32 {
+				ylo = xhi
+			} else if sh < 64 {
+				ylo = xhi >> (sh - 32)
+			}
+		}
+	} else {
+		/* v = (hi||lo) << -sh */
+		sh := uint32(-sh)
+		if sh <= 11 {
+			ylo = xlo << sh
+			yhi = xhi<>(32-sh)
+		} else {
+			/* overflow */
+			*y = 0xffffffffffffffff
+			return
+		}
+	}
+	*y = uint64(yhi)<<32 | uint64(ylo)
+}
 func uint64div(n, d uint64) uint64 {
 	// Check for 32 bit operands
 	if uint32(n>>32) == 0 && uint32(d>>32) == 0 {
diff --git a/test/convert5.go b/test/convert5.go
index 1bd74abdad0715..57585ef76e1673 100644
--- a/test/convert5.go
+++ b/test/convert5.go
@@ -4,9 +4,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !wasm && !386 && !arm && !mips
+//go:build !wasm
 
-// TODO fix this to work for wasm and 32-bit architectures.
+// TODO fix this to work for wasm
 // Doing more than this, however, expands the change.
 
 package main

From b9f3accdcf973ca41069e22e6859b9436801aae5 Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Mon, 6 Oct 2025 15:01:03 -0400
Subject: [PATCH 108/229] runtime: adjust softfloat corner cases to match
 amd64/arm64

This chooses saturating behavior for over/underflow.

Change-Id: I96a33ef73feacdafe8310f893de445060bc1a536
Reviewed-on: https://go-review.googlesource.com/c/go/+/709595
Reviewed-by: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
---
 src/runtime/export_test.go      |  1 +
 src/runtime/softfloat64.go      | 93 +++++++++++++++++++++++++--------
 src/runtime/softfloat64_test.go | 33 +++++++++++-
 test/convert5.go                |  5 ++
 4 files changed, 107 insertions(+), 25 deletions(-)

diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index 9f2fcacc30ee5c..f61cac763cef3d 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -25,6 +25,7 @@ var F32to64 = f32to64
 var Fcmp64 = fcmp64
 var Fintto64 = fintto64
 var F64toint = f64toint
+var F64touint = f64touint64
 
 var Entersyscall = entersyscall
 var Exitsyscall = exitsyscall
diff --git a/src/runtime/softfloat64.go b/src/runtime/softfloat64.go
index 42ef0092970b3e..7b9409f75be380 100644
--- a/src/runtime/softfloat64.go
+++ b/src/runtime/softfloat64.go
@@ -26,6 +26,11 @@ const (
 	neg32 uint32 = 1 << (expbits32 + mantbits32)
 )
 
+// If F is not NaN and not Inf, then f == (-1)**sign * mantissa * 2**(exp-52)
+// The mantissa and exp are adjusted from their stored representation  so
+// that the mantissa includes the formerly implicit 1, the exponent bias
+// is removed, and denormalized floats to put a 1 in the expected
+// (1< 63: // f >= 2^63
-		if fs != 0 && fm == 0 { // f == -2^63
-			return -1 << 63, true
-		}
+	case fi || fe >= 63: // |f| >= 2^63, including infinity
 		if fs != 0 {
-			return 0, false
+			return -0x8000_0000_0000_0000, true
 		}
-		return 0, false
+		return 0x7fff_ffff_ffff_ffff, true
 	}
 
 	for fe > int(mantbits64) {
@@ -400,12 +406,51 @@ func f64toint(f uint64) (val int64, ok bool) {
 		fm >>= 1
 	}
 	val = int64(fm)
+	if val < 0 {
+		if fs != 0 {
+			return -0x8000_0000_0000_0000, true
+		}
+		return 0x7fff_ffff_ffff_ffff, true
+	}
 	if fs != 0 {
 		val = -val
 	}
 	return val, true
 }
 
+// returns saturated-conversion uint64 value of f
+// and whether the input was NaN (in which case it
+// may not match the "hardware" conversion).
+func f64touint(f uint64) (val uint64, isNan bool) {
+	fs, fm, fe, fi, fn := funpack64(f)
+
+	switch {
+
+	case fn: // NaN
+		return 0xffff_ffff_ffff_ffff, false
+
+	case fs != 0: // all negative, including -Inf, are zero
+		return 0, true
+
+	case fi || fe >= 64: // positive infinity or f >= 2^64
+		return 0xffff_ffff_ffff_ffff, true
+
+	case fe < -1: // f < 0.5
+		return 0, true
+	}
+
+	for fe > int(mantbits64) {
+		fe--
+		fm <<= 1
+	}
+	for fe < int(mantbits64) {
+		fe++
+		fm >>= 1
+	}
+	val = fm
+	return val, true
+}
+
 func fintto64(val int64) (f uint64) {
 	fs := uint64(val) & (1 << 63)
 	mant := uint64(val)
@@ -564,6 +609,12 @@ func fint64to64(x int64) uint64 {
 
 func f32toint32(x uint32) int32 {
 	val, _ := f64toint(f32to64(x))
+	if val >= 0x7fffffff {
+		return 0x7fffffff
+	}
+	if val < -0x80000000 {
+		return -0x80000000
+	}
 	return int32(val)
 }
 
@@ -574,6 +625,12 @@ func f32toint64(x uint32) int64 {
 
 func f64toint32(x uint64) int32 {
 	val, _ := f64toint(x)
+	if val >= 0x7fffffff {
+		return 0x7fffffff
+	}
+	if val < -0x80000000 {
+		return -0x80000000
+	}
 	return int32(val)
 }
 
@@ -583,23 +640,13 @@ func f64toint64(x uint64) int64 {
 }
 
 func f64touint64(x uint64) uint64 {
-	var m uint64 = 0x43e0000000000000 // float64 1<<63
-	if fgt64(m, x) {
-		return uint64(f64toint64(x))
-	}
-	y := fadd64(x, -m)
-	z := uint64(f64toint64(y))
-	return z | (1 << 63)
+	val, _ := f64touint(x)
+	return val
 }
 
 func f32touint64(x uint32) uint64 {
-	var m uint32 = 0x5f000000 // float32 1<<63
-	if fgt32(m, x) {
-		return uint64(f32toint64(x))
-	}
-	y := fadd32(x, -m)
-	z := uint64(f32toint64(y))
-	return z | (1 << 63)
+	val, _ := f64touint(f32to64(x))
+	return val
 }
 
 func fuint64to64(x uint64) uint64 {
diff --git a/src/runtime/softfloat64_test.go b/src/runtime/softfloat64_test.go
index 3f53e8bc55810c..233d5e01c0ea60 100644
--- a/src/runtime/softfloat64_test.go
+++ b/src/runtime/softfloat64_test.go
@@ -28,6 +28,15 @@ func div(x, y float64) float64 { return x / y }
 func TestFloat64(t *testing.T) {
 	base := []float64{
 		0,
+		1,
+		-9223372036854775808,
+		-9223372036854775808 + 4096,
+		18446744073709551615,
+		18446744073709551615 + 1,
+		18446744073709551615 - 1,
+		9223372036854775808 + 4096,
+		0.5,
+		0.75,
 		math.Copysign(0, -1),
 		-1,
 		1,
@@ -35,6 +44,8 @@ func TestFloat64(t *testing.T) {
 		math.Inf(+1),
 		math.Inf(-1),
 		0.1,
+		0.5,
+		0.75,
 		1.5,
 		1.9999999999999998,     // all 1s mantissa
 		1.3333333333333333,     // 1.010101010101...
@@ -70,7 +81,7 @@ func TestFloat64(t *testing.T) {
 		1e+307,
 		1e+308,
 	}
-	all := make([]float64, 200)
+	all := make([]float64, 250)
 	copy(all, base)
 	for i := len(base); i < len(all); i++ {
 		all[i] = rand.NormFloat64()
@@ -82,6 +93,7 @@ func TestFloat64(t *testing.T) {
 		test(t, "*", mul, fop(Fmul64), all)
 		test(t, "/", div, fop(Fdiv64), all)
 	}
+
 }
 
 // 64 -hw-> 32 -hw-> 64
@@ -104,6 +116,11 @@ func hwint64(f float64) float64 {
 	return float64(int64(f))
 }
 
+// float64 -hw-> uint64 -hw-> float64
+func hwuint64(f float64) float64 {
+	return float64(uint64(f))
+}
+
 // float64 -hw-> int32 -hw-> float64
 func hwint32(f float64) float64 {
 	return float64(int32(f))
@@ -113,13 +130,23 @@ func hwint32(f float64) float64 {
 func toint64sw(f float64) float64 {
 	i, ok := F64toint(math.Float64bits(f))
 	if !ok {
-		// There's no right answer for out of range.
+		// There's no right answer for NaN.
 		// Match the hardware to pass the test.
 		i = int64(f)
 	}
 	return float64(i)
 }
 
+func touint64sw(f float64) float64 {
+	i := F64touint(math.Float64bits(f))
+	if f != f {
+		// There's no right answer for NaN.
+		// Match the hardware to pass the test.
+		i = uint64(f)
+	}
+	return float64(i)
+}
+
 // float64 -hw-> int64 -sw-> float64
 func fromint64sw(f float64) float64 {
 	return math.Float64frombits(Fintto64(int64(f)))
@@ -150,6 +177,7 @@ func test(t *testing.T, op string, hw, sw func(float64, float64) float64, all []
 			testu(t, "to32", trunc32, to32sw, h)
 			testu(t, "to64", trunc32, to64sw, h)
 			testu(t, "toint64", hwint64, toint64sw, h)
+			testu(t, "touint64", hwuint64, touint64sw, h)
 			testu(t, "fromint64", hwint64, fromint64sw, h)
 			testcmp(t, f, h)
 			testcmp(t, h, f)
@@ -163,6 +191,7 @@ func testu(t *testing.T, op string, hw, sw func(float64) float64, v float64) {
 	h := hw(v)
 	s := sw(v)
 	if !same(h, s) {
+		s = sw(v) // debug me
 		err(t, "%s %g = sw %g, hw %g\n", op, v, s, h)
 	}
 }
diff --git a/test/convert5.go b/test/convert5.go
index 57585ef76e1673..27aa7867f42824 100644
--- a/test/convert5.go
+++ b/test/convert5.go
@@ -62,6 +62,8 @@ func main() {
 	p64_plus4k_plus1 := id(float64(p64 + 4096 + 1)) // want this to be precise and fit in 53 bits mantissa
 	n32_minus4k := id(float32(n32 - 4096))
 	n64_minus4k := id(float64(n64 - 4096))
+	n32_plus4k := id(float32(n32 + 4096))
+	n64_plus4k := id(float64(n64 + 4096))
 	inf_32 := id(float32(one / 0))
 	inf_64 := id(float64(one / 0))
 	ninf_32 := id(float32(-one / 0))
@@ -79,6 +81,7 @@ func main() {
 		{"p64_plus4k_plus1", p64_plus4k_plus1, p32},
 		{"n32_minus4k", n32_minus4k, n32},
 		{"n64_minus4k", n64_minus4k, n32},
+		{"n32_plus4k", n32_plus4k, n32 + 4096},
 		{"inf_32", inf_32, p32},
 		{"inf_64", inf_64, p32},
 		{"ninf_32", ninf_32, n32},
@@ -108,6 +111,8 @@ func main() {
 		{"p64_plus4k_plus1", p64_plus4k_plus1, p64},
 		{"n32_minus4k", n32_minus4k, n32 - 4096},
 		{"n64_minus4k", n64_minus4k, n64},
+		{"n32_plus4k", n32_plus4k, n32 + 4096},
+		{"n64_plus4k", n64_plus4k, n64 + 4096},
 		{"inf_32", inf_32, p64},
 		{"inf_64", inf_64, p64},
 		{"ninf_32", ninf_32, n64},

From 8d810286b3121b601480426159c04d178fa29166 Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Wed, 1 Oct 2025 11:29:13 -0400
Subject: [PATCH 109/229] cmd/compile: make wasm match other platforms for
 FP->int32/64 conversions

this change is for overflows, so that all the platforms agree.

Change-Id: I9f459353615bf24ef8a5de641063d9ce34986241
Reviewed-on: https://go-review.googlesource.com/c/go/+/708358
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/internal/ssa/_gen/Wasm.rules |  9 ++--
 src/cmd/compile/internal/ssa/_gen/WasmOps.go | 17 ++++--
 src/cmd/compile/internal/ssa/opGen.go        | 56 ++++++++++++++++++++
 src/cmd/compile/internal/ssa/rewriteWasm.go  |  8 +--
 src/cmd/compile/internal/wasm/ssa.go         | 11 ++++
 test/convert5.go                             |  5 --
 6 files changed, 89 insertions(+), 17 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/_gen/Wasm.rules b/src/cmd/compile/internal/ssa/_gen/Wasm.rules
index f632a01109f764..bb123bc3cc48e7 100644
--- a/src/cmd/compile/internal/ssa/_gen/Wasm.rules
+++ b/src/cmd/compile/internal/ssa/_gen/Wasm.rules
@@ -76,13 +76,14 @@
 (Cvt32Uto(64|32)F x) => (F(64|32)ConvertI64U (ZeroExt32to64 x))
 (Cvt64Uto(64|32)F ...) => (F(64|32)ConvertI64U ...)
 
-(Cvt32Fto32 ...) => (I64TruncSatF32S ...)
+(Cvt32Fto32 ...) => (I32TruncSatF32S ...)
 (Cvt32Fto64 ...) => (I64TruncSatF32S ...)
-(Cvt64Fto32 ...) => (I64TruncSatF64S ...)
+(Cvt64Fto32 ...) => (I32TruncSatF64S ...)
 (Cvt64Fto64 ...) => (I64TruncSatF64S ...)
-(Cvt32Fto32U ...) => (I64TruncSatF32U ...)
+
+(Cvt32Fto32U ...) => (I32TruncSatF32U ...)
 (Cvt32Fto64U ...) => (I64TruncSatF32U ...)
-(Cvt64Fto32U ...) => (I64TruncSatF64U ...)
+(Cvt64Fto32U ...) => (I32TruncSatF64U ...)
 (Cvt64Fto64U ...) => (I64TruncSatF64U ...)
 
 (Cvt32Fto64F ...) => (F64PromoteF32 ...)
diff --git a/src/cmd/compile/internal/ssa/_gen/WasmOps.go b/src/cmd/compile/internal/ssa/_gen/WasmOps.go
index 45bbed5f520201..b63f28a2193a2f 100644
--- a/src/cmd/compile/internal/ssa/_gen/WasmOps.go
+++ b/src/cmd/compile/internal/ssa/_gen/WasmOps.go
@@ -222,10 +222,19 @@ func init() {
 		{name: "F64Mul", asm: "F64Mul", argLength: 2, reg: fp64_21, typ: "Float64"}, // arg0 * arg1
 		{name: "F64Div", asm: "F64Div", argLength: 2, reg: fp64_21, typ: "Float64"}, // arg0 / arg1
 
-		{name: "I64TruncSatF64S", asm: "I64TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to a signed integer (saturating)
-		{name: "I64TruncSatF64U", asm: "I64TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to an unsigned integer (saturating)
-		{name: "I64TruncSatF32S", asm: "I64TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to a signed integer (saturating)
-		{name: "I64TruncSatF32U", asm: "I64TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to an unsigned integer (saturating)
+		{name: "I64TruncSatF64S", asm: "I64TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
+		{name: "I64TruncSatF64U", asm: "I64TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
+		{name: "I64TruncSatF32S", asm: "I64TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
+		{name: "I64TruncSatF32U", asm: "I64TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
+
+		// It appears to be wasm convention that everything lands in a 64-bit register;
+		// the WASM instructions for these operations produce 32-bit width results, but
+		// wasm/ssa.go widens them appropriately to 64-bit results.
+		{name: "I32TruncSatF64S", asm: "I32TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
+		{name: "I32TruncSatF64U", asm: "I32TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
+		{name: "I32TruncSatF32S", asm: "I32TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
+		{name: "I32TruncSatF32U", asm: "I32TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
+
 		{name: "F32ConvertI64S", asm: "F32ConvertI64S", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp32}}, typ: "Float32"}, // converts the signed integer arg0 to a float
 		{name: "F32ConvertI64U", asm: "F32ConvertI64U", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp32}}, typ: "Float32"}, // converts the unsigned integer arg0 to a float
 		{name: "F64ConvertI64S", asm: "F64ConvertI64S", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp64}}, typ: "Float64"}, // converts the signed integer arg0 to a float
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 2a60398bc68711..32ba3a89856ed4 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -2980,6 +2980,10 @@ const (
 	OpWasmI64TruncSatF64U
 	OpWasmI64TruncSatF32S
 	OpWasmI64TruncSatF32U
+	OpWasmI32TruncSatF64S
+	OpWasmI32TruncSatF64U
+	OpWasmI32TruncSatF32S
+	OpWasmI32TruncSatF32U
 	OpWasmF32ConvertI64S
 	OpWasmF32ConvertI64U
 	OpWasmF64ConvertI64S
@@ -40296,6 +40300,58 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
+	{
+		name:   "I32TruncSatF64S",
+		argLen: 1,
+		asm:    wasm.AI32TruncSatF64S,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 281470681743360}, // F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+			outputs: []outputInfo{
+				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
+			},
+		},
+	},
+	{
+		name:   "I32TruncSatF64U",
+		argLen: 1,
+		asm:    wasm.AI32TruncSatF64U,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 281470681743360}, // F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
+			},
+			outputs: []outputInfo{
+				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
+			},
+		},
+	},
+	{
+		name:   "I32TruncSatF32S",
+		argLen: 1,
+		asm:    wasm.AI32TruncSatF32S,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 4294901760}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15
+			},
+			outputs: []outputInfo{
+				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
+			},
+		},
+	},
+	{
+		name:   "I32TruncSatF32U",
+		argLen: 1,
+		asm:    wasm.AI32TruncSatF32U,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 4294901760}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15
+			},
+			outputs: []outputInfo{
+				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
+			},
+		},
+	},
 	{
 		name:   "F32ConvertI64S",
 		argLen: 1,
diff --git a/src/cmd/compile/internal/ssa/rewriteWasm.go b/src/cmd/compile/internal/ssa/rewriteWasm.go
index a164a6eee555b9..dd73d3a5e705ed 100644
--- a/src/cmd/compile/internal/ssa/rewriteWasm.go
+++ b/src/cmd/compile/internal/ssa/rewriteWasm.go
@@ -120,10 +120,10 @@ func rewriteValueWasm(v *Value) bool {
 		v.Op = OpWasmI64Ctz
 		return true
 	case OpCvt32Fto32:
-		v.Op = OpWasmI64TruncSatF32S
+		v.Op = OpWasmI32TruncSatF32S
 		return true
 	case OpCvt32Fto32U:
-		v.Op = OpWasmI64TruncSatF32U
+		v.Op = OpWasmI32TruncSatF32U
 		return true
 	case OpCvt32Fto64:
 		v.Op = OpWasmI64TruncSatF32S
@@ -143,13 +143,13 @@ func rewriteValueWasm(v *Value) bool {
 	case OpCvt32to64F:
 		return rewriteValueWasm_OpCvt32to64F(v)
 	case OpCvt64Fto32:
-		v.Op = OpWasmI64TruncSatF64S
+		v.Op = OpWasmI32TruncSatF64S
 		return true
 	case OpCvt64Fto32F:
 		v.Op = OpWasmF32DemoteF64
 		return true
 	case OpCvt64Fto32U:
-		v.Op = OpWasmI64TruncSatF64U
+		v.Op = OpWasmI32TruncSatF64U
 		return true
 	case OpCvt64Fto64:
 		v.Op = OpWasmI64TruncSatF64S
diff --git a/src/cmd/compile/internal/wasm/ssa.go b/src/cmd/compile/internal/wasm/ssa.go
index 1e3b318e8c9fe0..8ebc90288572a3 100644
--- a/src/cmd/compile/internal/wasm/ssa.go
+++ b/src/cmd/compile/internal/wasm/ssa.go
@@ -430,6 +430,17 @@ func ssaGenValueOnStack(s *ssagen.State, v *ssa.Value, extend bool) {
 		getValue64(s, v.Args[0])
 		s.Prog(v.Op.Asm())
 
+		// 32-bit integer conversion results
+	case ssa.OpWasmI32TruncSatF32S, ssa.OpWasmI32TruncSatF64S:
+		getValue64(s, v.Args[0])
+		s.Prog(v.Op.Asm())
+		s.Prog(wasm.AI64ExtendI32S)
+
+	case ssa.OpWasmI32TruncSatF32U, ssa.OpWasmI32TruncSatF64U:
+		getValue64(s, v.Args[0])
+		s.Prog(v.Op.Asm())
+		s.Prog(wasm.AI64ExtendI32U)
+
 	case ssa.OpWasmF32DemoteF64:
 		getValue64(s, v.Args[0])
 		s.Prog(v.Op.Asm())
diff --git a/test/convert5.go b/test/convert5.go
index 27aa7867f42824..4688fae85587d4 100644
--- a/test/convert5.go
+++ b/test/convert5.go
@@ -4,11 +4,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !wasm
-
-// TODO fix this to work for wasm
-// Doing more than this, however, expands the change.
-
 package main
 
 import (

From 9db7e30bb42eed9912f5e7e9e3959f3b38879d5b Mon Sep 17 00:00:00 2001
From: Roland Shoemaker 
Date: Wed, 8 Oct 2025 17:13:12 -0700
Subject: [PATCH 110/229] net/url: allow IP-literals with IPv4-mapped IPv6
 addresses

The security fix we applied in CL709857 was overly broad. It applied
rules from RFC 2732, which disallowed IPv4-mapped IPv6 addresses, but
these were later allowed in RFC 3986, which is the canonical URI syntax
RFC.

Revert the portion of CL709857 which restricted IPv4-mapped addresses,
and update the related tests.

Fixes #75815

Change-Id: I3192f2275ad5c386f5c15006a6716bdb5282919d
Reviewed-on: https://go-review.googlesource.com/c/go/+/710375
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Ethan Lee 
Auto-Submit: Roland Shoemaker 
---
 src/net/url/url.go      |  6 +++---
 src/net/url/url_test.go | 23 ++++++++++++-----------
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/net/url/url.go b/src/net/url/url.go
index 292bc6bb12187a..6afa30f162bd25 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -689,13 +689,13 @@ func parseHost(host string) (string, error) {
 
 		// Per RFC 3986, only a host identified by a valid
 		// IPv6 address can be enclosed by square brackets.
-		// This excludes any IPv4 or IPv4-mapped addresses.
+		// This excludes any IPv4, but notably not IPv4-mapped addresses.
 		addr, err := netip.ParseAddr(unescapedHostname)
 		if err != nil {
 			return "", fmt.Errorf("invalid host: %w", err)
 		}
-		if addr.Is4() || addr.Is4In6() {
-			return "", errors.New("invalid IPv6 host")
+		if addr.Is4() {
+			return "", errors.New("invalid IP-literal")
 		}
 		return "[" + unescapedHostname + "]" + unescapedColonPort, nil
 	} else if i := strings.LastIndex(host, ":"); i != -1 {
diff --git a/src/net/url/url_test.go b/src/net/url/url_test.go
index 32065583f27dd7..6084facacc0519 100644
--- a/src/net/url/url_test.go
+++ b/src/net/url/url_test.go
@@ -726,7 +726,7 @@ var parseRequestURLTests = []struct {
 	{"https://[2001:db8::1]/path", true},            // compressed IPv6 address with path
 	{"https://[fe80::1%25eth0]/path?query=1", true}, // link-local with zone, path, and query
 
-	{"https://[::ffff:192.0.2.1]", false},
+	{"https://[::ffff:192.0.2.1]", true},
 	{"https://[:1] ", false},
 	{"https://[1:2:3:4:5:6:7:8:9]", false},
 	{"https://[1::1::1]", false},
@@ -1672,16 +1672,17 @@ func TestParseErrors(t *testing.T) {
 		{"cache_object:foo/bar", true},
 		{"cache_object/:foo/bar", false},
 
-		{"http://[192.168.0.1]/", true},             // IPv4 in brackets
-		{"http://[192.168.0.1]:8080/", true},        // IPv4 in brackets with port
-		{"http://[::ffff:192.168.0.1]/", true},      // IPv4-mapped IPv6 in brackets
-		{"http://[::ffff:192.168.0.1]:8080/", true}, // IPv4-mapped IPv6 in brackets with port
-		{"http://[::ffff:c0a8:1]/", true},           // IPv4-mapped IPv6 in brackets (hex)
-		{"http://[not-an-ip]/", true},               // invalid IP string in brackets
-		{"http://[fe80::1%foo]/", true},             // invalid zone format in brackets
-		{"http://[fe80::1", true},                   // missing closing bracket
-		{"http://fe80::1]/", true},                  // missing opening bracket
-		{"http://[test.com]/", true},                // domain name in brackets
+		{"http://[192.168.0.1]/", true},              // IPv4 in brackets
+		{"http://[192.168.0.1]:8080/", true},         // IPv4 in brackets with port
+		{"http://[::ffff:192.168.0.1]/", false},      // IPv4-mapped IPv6 in brackets
+		{"http://[::ffff:192.168.0.1000]/", true},    // Out of range IPv4-mapped IPv6 in brackets
+		{"http://[::ffff:192.168.0.1]:8080/", false}, // IPv4-mapped IPv6 in brackets with port
+		{"http://[::ffff:c0a8:1]/", false},           // IPv4-mapped IPv6 in brackets (hex)
+		{"http://[not-an-ip]/", true},                // invalid IP string in brackets
+		{"http://[fe80::1%foo]/", true},              // invalid zone format in brackets
+		{"http://[fe80::1", true},                    // missing closing bracket
+		{"http://fe80::1]/", true},                   // missing opening bracket
+		{"http://[test.com]/", true},                 // domain name in brackets
 	}
 	for _, tt := range tests {
 		u, err := Parse(tt.in)

From 80f3bb5516bb12233a15167bc8ba9d39cca5b535 Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Thu, 9 Oct 2025 21:13:59 +0000
Subject: [PATCH 111/229] reflect: remove timeout in TestChanOfGC

This test has an arbitrary 5 second timeout, and this seems to fire on
Darwin with mayMoreStackMove enabled (which is slow). Just rely on the
regular test timeout instead of this arbitrary shorter timeout to
eliminate the possibility that the test is just too slow.

On my Linux VM, I can get this test to take up to 2 seconds with
mayMoreStackMove set on all the same packages dist does, so this failure
mode is actually plausible.

Fixes #75742.

Change-Id: Iebcc859cab26e9205b57b869690162a9a424dfce
Reviewed-on: https://go-review.googlesource.com/c/go/+/710618
Reviewed-by: Cherry Mui 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Michael Knyszek 
---
 src/reflect/all_test.go | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/src/reflect/all_test.go b/src/reflect/all_test.go
index 2a8c5206624146..c6610b1968a834 100644
--- a/src/reflect/all_test.go
+++ b/src/reflect/all_test.go
@@ -6198,19 +6198,6 @@ func TestChanOfDir(t *testing.T) {
 }
 
 func TestChanOfGC(t *testing.T) {
-	done := make(chan bool, 1)
-	go func() {
-		select {
-		case <-done:
-		case <-time.After(5 * time.Second):
-			panic("deadlock in TestChanOfGC")
-		}
-	}()
-
-	defer func() {
-		done <- true
-	}()
-
 	type T *uintptr
 	tt := TypeOf(T(nil))
 	ct := ChanOf(BothDir, tt)

From 19a30ea3f250f8d6258f3e08aa3561f1193fdd38 Mon Sep 17 00:00:00 2001
From: Michael Matloob 
Date: Mon, 29 Sep 2025 17:26:49 -0400
Subject: [PATCH 112/229] cmd/compile: call generated size-specialized malloc
 functions directly

This change creates calls to size-specialized malloc functions instead
of calls to newObject when we know the size of the allocation at
compilation time. Most of it is a matter of calling the newObject
function (which will create calls to the size-specialized functions)
rather then the newObjectNonSpecialized function (which won't). In the
newHeapaddr, small, non-pointer case, we'll create a non specialized
newObject and transform that into the appropriate size-specialized
function when we produce the mallocgc in flushPendingHeapAllocations.

We have to update some of the rewrites in generic.rules to also apply to
the size-specialized functions when they apply to newObject.

The messiest thing is we have to adjust the offset we use to save the
memory profiler stack, because the depth of the call to profilealloc is
two frames fewer in the size-specialized malloc functions compared to
when newObject calls mallocgc. A bunch of tests have been adjusted to
account for that.

Change-Id: I6a6a6964c9037fb6719e392c4a498ed700b617d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/707856
Reviewed-by: Michael Knyszek 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/internal/ir/symtab.go         | 85 ++++++++++---------
 .../compile/internal/ssa/_gen/generic.rules   | 24 +++---
 src/cmd/compile/internal/ssa/rewrite.go       | 20 +++++
 .../compile/internal/ssa/rewritegeneric.go    | 42 +++++----
 src/cmd/compile/internal/ssa/writebarrier.go  | 13 ++-
 src/cmd/compile/internal/ssagen/ssa.go        | 81 ++++++++++++++++--
 src/cmd/dist/buildtool.go                     |  1 +
 src/runtime/mprof.go                          |  4 +-
 src/runtime/pprof/mprof_test.go               |  8 +-
 src/runtime/pprof/pprof_test.go               |  4 +-
 test/codegen/strings.go                       |  2 +-
 test/fixedbugs/issue15747.go                  |  4 +-
 test/heapsampling.go                          | 24 +++---
 test/live.go                                  | 10 +--
 test/live_regabi.go                           | 10 +--
 test/uintptrescapes2.go                       | 12 +--
 16 files changed, 228 insertions(+), 116 deletions(-)

diff --git a/src/cmd/compile/internal/ir/symtab.go b/src/cmd/compile/internal/ir/symtab.go
index ee0f52fbf3f3b8..f8eb4578809312 100644
--- a/src/cmd/compile/internal/ir/symtab.go
+++ b/src/cmd/compile/internal/ir/symtab.go
@@ -13,47 +13,50 @@ import (
 var Syms symsStruct
 
 type symsStruct struct {
-	AssertE2I         *obj.LSym
-	AssertE2I2        *obj.LSym
-	Asanread          *obj.LSym
-	Asanwrite         *obj.LSym
-	CgoCheckMemmove   *obj.LSym
-	CgoCheckPtrWrite  *obj.LSym
-	CheckPtrAlignment *obj.LSym
-	Deferproc         *obj.LSym
-	Deferprocat       *obj.LSym
-	DeferprocStack    *obj.LSym
-	Deferreturn       *obj.LSym
-	Duffcopy          *obj.LSym
-	Duffzero          *obj.LSym
-	GCWriteBarrier    [8]*obj.LSym
-	Goschedguarded    *obj.LSym
-	Growslice         *obj.LSym
-	InterfaceSwitch   *obj.LSym
-	MallocGC          *obj.LSym
-	Memmove           *obj.LSym
-	Msanread          *obj.LSym
-	Msanwrite         *obj.LSym
-	Msanmove          *obj.LSym
-	Newobject         *obj.LSym
-	Newproc           *obj.LSym
-	PanicBounds       *obj.LSym
-	PanicExtend       *obj.LSym
-	Panicdivide       *obj.LSym
-	Panicshift        *obj.LSym
-	PanicdottypeE     *obj.LSym
-	PanicdottypeI     *obj.LSym
-	Panicnildottype   *obj.LSym
-	Panicoverflow     *obj.LSym
-	Racefuncenter     *obj.LSym
-	Racefuncexit      *obj.LSym
-	Raceread          *obj.LSym
-	Racereadrange     *obj.LSym
-	Racewrite         *obj.LSym
-	Racewriterange    *obj.LSym
-	TypeAssert        *obj.LSym
-	WBZero            *obj.LSym
-	WBMove            *obj.LSym
+	AssertE2I                 *obj.LSym
+	AssertE2I2                *obj.LSym
+	Asanread                  *obj.LSym
+	Asanwrite                 *obj.LSym
+	CgoCheckMemmove           *obj.LSym
+	CgoCheckPtrWrite          *obj.LSym
+	CheckPtrAlignment         *obj.LSym
+	Deferproc                 *obj.LSym
+	Deferprocat               *obj.LSym
+	DeferprocStack            *obj.LSym
+	Deferreturn               *obj.LSym
+	Duffcopy                  *obj.LSym
+	Duffzero                  *obj.LSym
+	GCWriteBarrier            [8]*obj.LSym
+	Goschedguarded            *obj.LSym
+	Growslice                 *obj.LSym
+	InterfaceSwitch           *obj.LSym
+	MallocGC                  *obj.LSym
+	MallocGCSmallNoScan       [27]*obj.LSym
+	MallocGCSmallScanNoHeader [27]*obj.LSym
+	MallocGCTiny              [16]*obj.LSym
+	Memmove                   *obj.LSym
+	Msanread                  *obj.LSym
+	Msanwrite                 *obj.LSym
+	Msanmove                  *obj.LSym
+	Newobject                 *obj.LSym
+	Newproc                   *obj.LSym
+	PanicBounds               *obj.LSym
+	PanicExtend               *obj.LSym
+	Panicdivide               *obj.LSym
+	Panicshift                *obj.LSym
+	PanicdottypeE             *obj.LSym
+	PanicdottypeI             *obj.LSym
+	Panicnildottype           *obj.LSym
+	Panicoverflow             *obj.LSym
+	Racefuncenter             *obj.LSym
+	Racefuncexit              *obj.LSym
+	Raceread                  *obj.LSym
+	Racereadrange             *obj.LSym
+	Racewrite                 *obj.LSym
+	Racewriterange            *obj.LSym
+	TypeAssert                *obj.LSym
+	WBZero                    *obj.LSym
+	WBMove                    *obj.LSym
 	// Wasm
 	SigPanic         *obj.LSym
 	Staticuint64s    *obj.LSym
diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules
index 048d9958dc7440..23ce21a8b2cc28 100644
--- a/src/cmd/compile/internal/ssa/_gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/_gen/generic.rules
@@ -2065,28 +2065,32 @@
 // for rewriting results of some late-expanded rewrites (below)
 (SelectN [n] m:(MakeResult ___)) => m.Args[n]
 
+// TODO(matloob): Try out having non-zeroing mallocs for prointerless
+// memory, and leaving the zeroing here. Then the compiler can remove
+// the zeroing if the user has explicit writes to the whole object.
+
 // for late-expanded calls, recognize newobject and remove zeroing and nilchecks
-(Zero (SelectN [0] call:(StaticLECall _ _)) mem:(SelectN [1] call))
-	&& isSameCall(call.Aux, "runtime.newobject")
+(Zero (SelectN [0] call:(StaticLECall ___)) mem:(SelectN [1] call))
+	&& isMalloc(call.Aux)
 	=> mem
 
-(Store (SelectN [0] call:(StaticLECall _ _)) x mem:(SelectN [1] call))
+(Store (SelectN [0] call:(StaticLECall ___)) x mem:(SelectN [1] call))
 	&& isConstZero(x)
-	&& isSameCall(call.Aux, "runtime.newobject")
+	&& isMalloc(call.Aux)
 	=> mem
 
-(Store (OffPtr (SelectN [0] call:(StaticLECall _ _))) x mem:(SelectN [1] call))
+(Store (OffPtr (SelectN [0] call:(StaticLECall ___))) x mem:(SelectN [1] call))
 	&& isConstZero(x)
-	&& isSameCall(call.Aux, "runtime.newobject")
+	&& isMalloc(call.Aux)
 	=> mem
 
-(NilCheck ptr:(SelectN [0] call:(StaticLECall _ _)) _)
-	&& isSameCall(call.Aux, "runtime.newobject")
+(NilCheck ptr:(SelectN [0] call:(StaticLECall ___)) _)
+	&& isMalloc(call.Aux)
 	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
 	=> ptr
 
-(NilCheck ptr:(OffPtr (SelectN [0] call:(StaticLECall _ _))) _)
-	&& isSameCall(call.Aux, "runtime.newobject")
+(NilCheck ptr:(OffPtr (SelectN [0] call:(StaticLECall ___))) _)
+	&& isMalloc(call.Aux)
 	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
 	=> ptr
 
diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go
index 47f225c7aeb7c0..f02019df384f5f 100644
--- a/src/cmd/compile/internal/ssa/rewrite.go
+++ b/src/cmd/compile/internal/ssa/rewrite.go
@@ -456,6 +456,26 @@ func isSameCall(aux Aux, name string) bool {
 	return fn != nil && fn.String() == name
 }
 
+func isMalloc(aux Aux) bool {
+	return isNewObject(aux) || isSpecializedMalloc(aux)
+}
+
+func isNewObject(aux Aux) bool {
+	fn := aux.(*AuxCall).Fn
+	return fn != nil && fn.String() == "runtime.newobject"
+}
+
+func isSpecializedMalloc(aux Aux) bool {
+	fn := aux.(*AuxCall).Fn
+	if fn == nil {
+		return false
+	}
+	name := fn.String()
+	return strings.HasPrefix(name, "runtime.mallocgcSmallNoScanSC") ||
+		strings.HasPrefix(name, "runtime.mallocgcSmallScanNoHeaderSC") ||
+		strings.HasPrefix(name, "runtime.mallocTiny")
+}
+
 // canLoadUnaligned reports if the architecture supports unaligned load operations.
 func canLoadUnaligned(c *Config) bool {
 	return c.ctxt.Arch.Alignment == 1
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 37ba324d86cec3..c36ecc1cc60fcc 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -21318,8 +21318,8 @@ func rewriteValuegeneric_OpNilCheck(v *Value) bool {
 		v.copyOf(ptr)
 		return true
 	}
-	// match: (NilCheck ptr:(SelectN [0] call:(StaticLECall _ _)) _)
-	// cond: isSameCall(call.Aux, "runtime.newobject") && warnRule(fe.Debug_checknil(), v, "removed nil check")
+	// match: (NilCheck ptr:(SelectN [0] call:(StaticLECall ___)) _)
+	// cond: isMalloc(call.Aux) && warnRule(fe.Debug_checknil(), v, "removed nil check")
 	// result: ptr
 	for {
 		ptr := v_0
@@ -21327,14 +21327,17 @@ func rewriteValuegeneric_OpNilCheck(v *Value) bool {
 			break
 		}
 		call := ptr.Args[0]
-		if call.Op != OpStaticLECall || len(call.Args) != 2 || !(isSameCall(call.Aux, "runtime.newobject") && warnRule(fe.Debug_checknil(), v, "removed nil check")) {
+		if call.Op != OpStaticLECall {
+			break
+		}
+		if !(isMalloc(call.Aux) && warnRule(fe.Debug_checknil(), v, "removed nil check")) {
 			break
 		}
 		v.copyOf(ptr)
 		return true
 	}
-	// match: (NilCheck ptr:(OffPtr (SelectN [0] call:(StaticLECall _ _))) _)
-	// cond: isSameCall(call.Aux, "runtime.newobject") && warnRule(fe.Debug_checknil(), v, "removed nil check")
+	// match: (NilCheck ptr:(OffPtr (SelectN [0] call:(StaticLECall ___))) _)
+	// cond: isMalloc(call.Aux) && warnRule(fe.Debug_checknil(), v, "removed nil check")
 	// result: ptr
 	for {
 		ptr := v_0
@@ -21346,7 +21349,10 @@ func rewriteValuegeneric_OpNilCheck(v *Value) bool {
 			break
 		}
 		call := ptr_0.Args[0]
-		if call.Op != OpStaticLECall || len(call.Args) != 2 || !(isSameCall(call.Aux, "runtime.newobject") && warnRule(fe.Debug_checknil(), v, "removed nil check")) {
+		if call.Op != OpStaticLECall {
+			break
+		}
+		if !(isMalloc(call.Aux) && warnRule(fe.Debug_checknil(), v, "removed nil check")) {
 			break
 		}
 		v.copyOf(ptr)
@@ -32463,27 +32469,27 @@ func rewriteValuegeneric_OpStore(v *Value) bool {
 		v.AddArg3(dst, e, mem)
 		return true
 	}
-	// match: (Store (SelectN [0] call:(StaticLECall _ _)) x mem:(SelectN [1] call))
-	// cond: isConstZero(x) && isSameCall(call.Aux, "runtime.newobject")
+	// match: (Store (SelectN [0] call:(StaticLECall ___)) x mem:(SelectN [1] call))
+	// cond: isConstZero(x) && isMalloc(call.Aux)
 	// result: mem
 	for {
 		if v_0.Op != OpSelectN || auxIntToInt64(v_0.AuxInt) != 0 {
 			break
 		}
 		call := v_0.Args[0]
-		if call.Op != OpStaticLECall || len(call.Args) != 2 {
+		if call.Op != OpStaticLECall {
 			break
 		}
 		x := v_1
 		mem := v_2
-		if mem.Op != OpSelectN || auxIntToInt64(mem.AuxInt) != 1 || call != mem.Args[0] || !(isConstZero(x) && isSameCall(call.Aux, "runtime.newobject")) {
+		if mem.Op != OpSelectN || auxIntToInt64(mem.AuxInt) != 1 || call != mem.Args[0] || !(isConstZero(x) && isMalloc(call.Aux)) {
 			break
 		}
 		v.copyOf(mem)
 		return true
 	}
-	// match: (Store (OffPtr (SelectN [0] call:(StaticLECall _ _))) x mem:(SelectN [1] call))
-	// cond: isConstZero(x) && isSameCall(call.Aux, "runtime.newobject")
+	// match: (Store (OffPtr (SelectN [0] call:(StaticLECall ___))) x mem:(SelectN [1] call))
+	// cond: isConstZero(x) && isMalloc(call.Aux)
 	// result: mem
 	for {
 		if v_0.Op != OpOffPtr {
@@ -32494,12 +32500,12 @@ func rewriteValuegeneric_OpStore(v *Value) bool {
 			break
 		}
 		call := v_0_0.Args[0]
-		if call.Op != OpStaticLECall || len(call.Args) != 2 {
+		if call.Op != OpStaticLECall {
 			break
 		}
 		x := v_1
 		mem := v_2
-		if mem.Op != OpSelectN || auxIntToInt64(mem.AuxInt) != 1 || call != mem.Args[0] || !(isConstZero(x) && isSameCall(call.Aux, "runtime.newobject")) {
+		if mem.Op != OpSelectN || auxIntToInt64(mem.AuxInt) != 1 || call != mem.Args[0] || !(isConstZero(x) && isMalloc(call.Aux)) {
 			break
 		}
 		v.copyOf(mem)
@@ -36842,19 +36848,19 @@ func rewriteValuegeneric_OpZero(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
 	b := v.Block
-	// match: (Zero (SelectN [0] call:(StaticLECall _ _)) mem:(SelectN [1] call))
-	// cond: isSameCall(call.Aux, "runtime.newobject")
+	// match: (Zero (SelectN [0] call:(StaticLECall ___)) mem:(SelectN [1] call))
+	// cond: isMalloc(call.Aux)
 	// result: mem
 	for {
 		if v_0.Op != OpSelectN || auxIntToInt64(v_0.AuxInt) != 0 {
 			break
 		}
 		call := v_0.Args[0]
-		if call.Op != OpStaticLECall || len(call.Args) != 2 {
+		if call.Op != OpStaticLECall {
 			break
 		}
 		mem := v_1
-		if mem.Op != OpSelectN || auxIntToInt64(mem.AuxInt) != 1 || call != mem.Args[0] || !(isSameCall(call.Aux, "runtime.newobject")) {
+		if mem.Op != OpSelectN || auxIntToInt64(mem.AuxInt) != 1 || call != mem.Args[0] || !(isMalloc(call.Aux)) {
 			break
 		}
 		v.copyOf(mem)
diff --git a/src/cmd/compile/internal/ssa/writebarrier.go b/src/cmd/compile/internal/ssa/writebarrier.go
index ec6901f13ec1d2..ec5a0fed29d791 100644
--- a/src/cmd/compile/internal/ssa/writebarrier.go
+++ b/src/cmd/compile/internal/ssa/writebarrier.go
@@ -798,7 +798,16 @@ func IsNewObject(v *Value, select1 []*Value) (mem *Value, ok bool) {
 	if call.Op != OpStaticCall {
 		return nil, false
 	}
-	if !isSameCall(call.Aux, "runtime.newobject") {
+	// Check for new object, or for new object calls that have been transformed into size-specialized malloc calls.
+	// Calls that have return type unsafe pointer may have originally been produced by flushPendingHeapAllocations
+	// in the ssa generator, so may have not originally been newObject calls.
+	var numParameters int64
+	switch {
+	case isNewObject(call.Aux):
+		numParameters = 1
+	case isSpecializedMalloc(call.Aux) && !v.Type.IsUnsafePtr():
+		numParameters = 3
+	default:
 		return nil, false
 	}
 	if f.ABIDefault == f.ABI1 && len(c.intParamRegs) >= 1 {
@@ -813,7 +822,7 @@ func IsNewObject(v *Value, select1 []*Value) (mem *Value, ok bool) {
 	if v.Args[0].Args[0].Op != OpSP {
 		return nil, false
 	}
-	if v.Args[0].AuxInt != c.ctxt.Arch.FixedFrameSize+c.RegSize { // offset of return value
+	if v.Args[0].AuxInt != c.ctxt.Arch.FixedFrameSize+numParameters*c.RegSize { // offset of return value
 		return nil, false
 	}
 	return mem, true
diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 2705195bd55791..57cd9084821237 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -12,6 +12,7 @@ import (
 	"go/constant"
 	"html"
 	"internal/buildcfg"
+	"internal/runtime/gc"
 	"os"
 	"path/filepath"
 	"slices"
@@ -124,6 +125,15 @@ func InitConfig() {
 	ir.Syms.Goschedguarded = typecheck.LookupRuntimeFunc("goschedguarded")
 	ir.Syms.Growslice = typecheck.LookupRuntimeFunc("growslice")
 	ir.Syms.InterfaceSwitch = typecheck.LookupRuntimeFunc("interfaceSwitch")
+	for i := 1; i < len(ir.Syms.MallocGCSmallNoScan); i++ {
+		ir.Syms.MallocGCSmallNoScan[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcSmallNoScanSC%d", i))
+	}
+	for i := 1; i < len(ir.Syms.MallocGCSmallScanNoHeader); i++ {
+		ir.Syms.MallocGCSmallScanNoHeader[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcSmallScanNoHeaderSC%d", i))
+	}
+	for i := 1; i < len(ir.Syms.MallocGCTiny); i++ {
+		ir.Syms.MallocGCTiny[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocTiny%d", i))
+	}
 	ir.Syms.MallocGC = typecheck.LookupRuntimeFunc("mallocgc")
 	ir.Syms.Memmove = typecheck.LookupRuntimeFunc("memmove")
 	ir.Syms.Msanread = typecheck.LookupRuntimeFunc("msanread")
@@ -690,7 +700,7 @@ func allocAlign(t *types.Type) int64 {
 func (s *state) newHeapaddr(n *ir.Name) {
 	size := allocSize(n.Type())
 	if n.Type().HasPointers() || size >= maxAggregatedHeapAllocation || size == 0 {
-		s.setHeapaddr(n.Pos(), n, s.newObject(n.Type(), nil))
+		s.setHeapaddr(n.Pos(), n, s.newObject(n.Type()))
 		return
 	}
 
@@ -709,7 +719,7 @@ func (s *state) newHeapaddr(n *ir.Name) {
 		// Make an allocation, but the type being allocated is just
 		// the first pending object. We will come back and update it
 		// later if needed.
-		allocCall = s.newObject(n.Type(), nil)
+		allocCall = s.newObjectNonSpecialized(n.Type(), nil)
 	} else {
 		allocCall = s.pendingHeapAllocations[0].Args[0]
 	}
@@ -762,7 +772,11 @@ func (s *state) flushPendingHeapAllocations() {
 		s.constBool(true),             // needZero TODO: false is ok?
 		call.Args[1],                  // memory
 	}
-	call.Aux = ssa.StaticAuxCall(ir.Syms.MallocGC, s.f.ABIDefault.ABIAnalyzeTypes(
+	mallocSym := ir.Syms.MallocGC
+	if specialMallocSym := s.specializedMallocSym(size, false); specialMallocSym != nil {
+		mallocSym = specialMallocSym
+	}
+	call.Aux = ssa.StaticAuxCall(mallocSym, s.f.ABIDefault.ABIAnalyzeTypes(
 		[]*types.Type{args[0].Type, args[1].Type, args[2].Type},
 		[]*types.Type{types.Types[types.TUNSAFEPTR]},
 	))
@@ -774,6 +788,43 @@ func (s *state) flushPendingHeapAllocations() {
 	ptr.Type = types.Types[types.TUNSAFEPTR]
 }
 
+func (s *state) specializedMallocSym(size int64, hasPointers bool) *obj.LSym {
+	if !s.sizeSpecializedMallocEnabled() {
+		return nil
+	}
+	ptrSize := s.config.PtrSize
+	ptrBits := ptrSize * 8
+	minSizeForMallocHeader := ptrSize * ptrBits
+	heapBitsInSpan := size <= minSizeForMallocHeader
+	if !heapBitsInSpan {
+		return nil
+	}
+	divRoundUp := func(n, a uintptr) uintptr { return (n + a - 1) / a }
+	sizeClass := gc.SizeToSizeClass8[divRoundUp(uintptr(size), gc.SmallSizeDiv)]
+	if hasPointers {
+		return ir.Syms.MallocGCSmallScanNoHeader[sizeClass]
+	}
+	if size < gc.TinySize {
+		return ir.Syms.MallocGCTiny[size]
+	}
+	return ir.Syms.MallocGCSmallNoScan[sizeClass]
+}
+
+func (s *state) sizeSpecializedMallocEnabled() bool {
+	if base.Flag.CompilingRuntime {
+		// The compiler forces the values of the asan, msan, and race flags to false if
+		// we're compiling the runtime, so we lose the information about whether we're
+		// building in asan, msan, or race mode. Because the specialized functions don't
+		// work in that mode, just turn if off in that case.
+		// TODO(matloob): Save the information about whether the flags were passed in
+		// originally so we can turn off size specialized malloc in that case instead
+		// using Instrumenting below. Then we can remove this condition.
+		return false
+	}
+
+	return buildcfg.Experiment.SizeSpecializedMalloc && !base.Flag.Cfg.Instrumenting
+}
+
 // setHeapaddr allocates a new PAUTO variable to store ptr (which must be non-nil)
 // and then sets it as n's heap address.
 func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
@@ -796,7 +847,24 @@ func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
 }
 
 // newObject returns an SSA value denoting new(typ).
-func (s *state) newObject(typ *types.Type, rtype *ssa.Value) *ssa.Value {
+func (s *state) newObject(typ *types.Type) *ssa.Value {
+	if typ.Size() == 0 {
+		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
+	}
+	rtype := s.reflectType(typ)
+	if specialMallocSym := s.specializedMallocSym(typ.Size(), typ.HasPointers()); specialMallocSym != nil {
+		return s.rtcall(specialMallocSym, true, []*types.Type{types.NewPtr(typ)},
+			s.constInt(types.Types[types.TUINTPTR], typ.Size()),
+			rtype,
+			s.constBool(true),
+		)[0]
+	}
+	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
+}
+
+// newObjectNonSpecialized returns an SSA value denoting new(typ). It does
+// not produce size-specialized malloc functions.
+func (s *state) newObjectNonSpecialized(typ *types.Type, rtype *ssa.Value) *ssa.Value {
 	if typ.Size() == 0 {
 		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
 	}
@@ -3594,11 +3662,10 @@ func (s *state) exprCheckPtr(n ir.Node, checkPtrOK bool) *ssa.Value {
 
 	case ir.ONEW:
 		n := n.(*ir.UnaryExpr)
-		var rtype *ssa.Value
 		if x, ok := n.X.(*ir.DynamicType); ok && x.Op() == ir.ODYNAMICTYPE {
-			rtype = s.expr(x.RType)
+			return s.newObjectNonSpecialized(n.Type().Elem(), s.expr(x.RType))
 		}
-		return s.newObject(n.Type().Elem(), rtype)
+		return s.newObject(n.Type().Elem())
 
 	case ir.OUNSAFEADD:
 		n := n.(*ir.BinaryExpr)
diff --git a/src/cmd/dist/buildtool.go b/src/cmd/dist/buildtool.go
index 080de832b2ad96..62cd9376927e0d 100644
--- a/src/cmd/dist/buildtool.go
+++ b/src/cmd/dist/buildtool.go
@@ -90,6 +90,7 @@ var bootstrapDirs = []string{
 	"internal/platform",
 	"internal/profile",
 	"internal/race",
+	"internal/runtime/gc",
 	"internal/saferio",
 	"internal/syscall/unix",
 	"internal/types/errors",
diff --git a/src/runtime/mprof.go b/src/runtime/mprof.go
index 0957e67b50fa2c..743fa5a3fe848b 100644
--- a/src/runtime/mprof.go
+++ b/src/runtime/mprof.go
@@ -49,7 +49,7 @@ const (
 	// desired maximum number of frames after expansion.
 	// This should be at least as large as the largest skip value
 	// used for profiling; otherwise stacks may be truncated inconsistently
-	maxSkip = 6
+	maxSkip = 8
 
 	// maxProfStackDepth is the highest valid value for debug.profstackdepth.
 	// It's used for the bucket.stk func.
@@ -444,7 +444,7 @@ func mProf_Malloc(mp *m, p unsafe.Pointer, size uintptr) {
 	}
 	// Only use the part of mp.profStack we need and ignore the extra space
 	// reserved for delayed inline expansion with frame pointer unwinding.
-	nstk := callers(5, mp.profStack[:debug.profstackdepth])
+	nstk := callers(3, mp.profStack[:debug.profstackdepth+2])
 	index := (mProfCycle.read() + 2) % uint32(len(memRecord{}.future))
 
 	b := stkbucket(memProfile, size, mp.profStack[:nstk], true)
diff --git a/src/runtime/pprof/mprof_test.go b/src/runtime/pprof/mprof_test.go
index 7c4a37e3c996fb..456ba9044498af 100644
--- a/src/runtime/pprof/mprof_test.go
+++ b/src/runtime/pprof/mprof_test.go
@@ -97,25 +97,25 @@ func TestMemoryProfiler(t *testing.T) {
 		legacy string
 	}{{
 		stk: []string{"runtime/pprof.allocatePersistent1K", "runtime/pprof.TestMemoryProfiler"},
-		legacy: fmt.Sprintf(`%v: %v \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
+		legacy: fmt.Sprintf(`%v: %v \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+( 0x[0-9,a-f]+ 0x[0-9,a-f]+)?
 #	0x[0-9,a-f]+	runtime/pprof\.allocatePersistent1K\+0x[0-9,a-f]+	.*runtime/pprof/mprof_test\.go:48
 #	0x[0-9,a-f]+	runtime/pprof\.TestMemoryProfiler\+0x[0-9,a-f]+	.*runtime/pprof/mprof_test\.go:87
 `, 32*memoryProfilerRun, 1024*memoryProfilerRun, 32*memoryProfilerRun, 1024*memoryProfilerRun),
 	}, {
 		stk: []string{"runtime/pprof.allocateTransient1M", "runtime/pprof.TestMemoryProfiler"},
-		legacy: fmt.Sprintf(`0: 0 \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
+		legacy: fmt.Sprintf(`0: 0 \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
 #	0x[0-9,a-f]+	runtime/pprof\.allocateTransient1M\+0x[0-9,a-f]+	.*runtime/pprof/mprof_test.go:25
 #	0x[0-9,a-f]+	runtime/pprof\.TestMemoryProfiler\+0x[0-9,a-f]+	.*runtime/pprof/mprof_test.go:84
 `, (1<<10)*memoryProfilerRun, (1<<20)*memoryProfilerRun),
 	}, {
 		stk: []string{"runtime/pprof.allocateTransient2M", "runtime/pprof.TestMemoryProfiler"},
-		legacy: fmt.Sprintf(`0: 0 \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
+		legacy: fmt.Sprintf(`0: 0 \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
 #	0x[0-9,a-f]+	runtime/pprof\.allocateTransient2M\+0x[0-9,a-f]+	.*runtime/pprof/mprof_test.go:31
 #	0x[0-9,a-f]+	runtime/pprof\.TestMemoryProfiler\+0x[0-9,a-f]+	.*runtime/pprof/mprof_test.go:85
 `, memoryProfilerRun, (2<<20)*memoryProfilerRun),
 	}, {
 		stk: []string{"runtime/pprof.allocateTransient2MInline", "runtime/pprof.TestMemoryProfiler"},
-		legacy: fmt.Sprintf(`0: 0 \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
+		legacy: fmt.Sprintf(`0: 0 \[%v: %v\] @ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+ 0x[0-9,a-f]+
 #	0x[0-9,a-f]+	runtime/pprof\.allocateTransient2MInline\+0x[0-9,a-f]+	.*runtime/pprof/mprof_test.go:35
 #	0x[0-9,a-f]+	runtime/pprof\.TestMemoryProfiler\+0x[0-9,a-f]+	.*runtime/pprof/mprof_test.go:86
 `, memoryProfilerRun, (2<<20)*memoryProfilerRun),
diff --git a/src/runtime/pprof/pprof_test.go b/src/runtime/pprof/pprof_test.go
index a538627099034e..6e6f4313a83dfa 100644
--- a/src/runtime/pprof/pprof_test.go
+++ b/src/runtime/pprof/pprof_test.go
@@ -2585,7 +2585,7 @@ func TestProfilerStackDepth(t *testing.T) {
 					t.Errorf("want stack depth = %d, got %d", depth, len(stk))
 				}
 
-				if rootFn, wantFn := stk[depth-1], "runtime/pprof.produceProfileEvents"; rootFn != wantFn {
+				if rootFn, wantFn := stk[depth-1], "runtime/pprof.allocDeep"; rootFn != wantFn {
 					t.Errorf("want stack stack root %s, got %v", wantFn, rootFn)
 				}
 			}
@@ -2660,7 +2660,7 @@ func goroutineDeep(t *testing.T, n int) {
 // guaranteed to have exactly the desired depth with produceProfileEvents as
 // their root frame which is expected by TestProfilerStackDepth.
 func produceProfileEvents(t *testing.T, depth int) {
-	allocDeep(depth - 1)       // -1 for produceProfileEvents, **
+	allocDeep(depth + 1)       // +1 for produceProfileEvents, **
 	blockChanDeep(t, depth-2)  // -2 for produceProfileEvents, **, chanrecv1
 	blockMutexDeep(t, depth-2) // -2 for produceProfileEvents, **, Unlock
 	memSink = nil
diff --git a/test/codegen/strings.go b/test/codegen/strings.go
index 498c3d398f8bc6..0b3ca7016ffc58 100644
--- a/test/codegen/strings.go
+++ b/test/codegen/strings.go
@@ -23,7 +23,7 @@ func CountBytes(s []byte) int {
 
 func ToByteSlice() []byte { // Issue #24698
 	// amd64:`LEAQ\ttype:\[3\]uint8`
-	// amd64:`CALL\truntime\.newobject`
+	// amd64:`CALL\truntime\.mallocTiny3`
 	// amd64:-`.*runtime.stringtoslicebyte`
 	return []byte("foo")
 }
diff --git a/test/fixedbugs/issue15747.go b/test/fixedbugs/issue15747.go
index 92e762c4e923ac..743adb6a8ffb1f 100644
--- a/test/fixedbugs/issue15747.go
+++ b/test/fixedbugs/issue15747.go
@@ -19,7 +19,7 @@ type T struct{ M string }
 
 var b bool
 
-func f1(q *Q, xx []byte) interface{} { // ERROR "live at call to newobject: xx$" "live at entry to f1: xx$"
+func f1(q *Q, xx []byte) interface{} { // ERROR "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: xx$" "live at entry to f1: xx$"
 	// xx was copied from the stack to the heap on the previous line:
 	// xx was live for the first two prints but then it switched to &xx
 	// being live. We should not see plain xx again.
@@ -36,7 +36,7 @@ func f1(q *Q, xx []byte) interface{} { // ERROR "live at call to newobject: xx$"
 //go:noinline
 func f2(d []byte, n int) (odata, res []byte, e interface{}) { // ERROR "live at entry to f2: d$"
 	if n > len(d) {
-		return d, nil, &T{M: "hello"} // ERROR "live at call to newobject: d"
+		return d, nil, &T{M: "hello"} // ERROR "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: d"
 	}
 	res = d[:n]
 	odata = d[n:]
diff --git a/test/heapsampling.go b/test/heapsampling.go
index 741db74f894d45..db93b253c90bab 100644
--- a/test/heapsampling.go
+++ b/test/heapsampling.go
@@ -48,22 +48,23 @@ func testInterleavedAllocations() error {
 	const iters = 50000
 	// Sizes of the allocations performed by each experiment.
 	frames := []string{"main.allocInterleaved1", "main.allocInterleaved2", "main.allocInterleaved3"}
+	leafFrame := "main.allocInterleaved"
 
 	// Pass if at least one of three experiments has no errors. Use a separate
 	// function for each experiment to identify each experiment in the profile.
 	allocInterleaved1(iters)
-	if checkAllocations(getMemProfileRecords(), frames[0:1], iters, allocInterleavedSizes) == nil {
+	if checkAllocations(getMemProfileRecords(), leafFrame, frames[0:1], iters, allocInterleavedSizes) == nil {
 		// Passed on first try, report no error.
 		return nil
 	}
 	allocInterleaved2(iters)
-	if checkAllocations(getMemProfileRecords(), frames[0:2], iters, allocInterleavedSizes) == nil {
+	if checkAllocations(getMemProfileRecords(), leafFrame, frames[0:2], iters, allocInterleavedSizes) == nil {
 		// Passed on second try, report no error.
 		return nil
 	}
 	allocInterleaved3(iters)
 	// If it fails a third time, we may be onto something.
-	return checkAllocations(getMemProfileRecords(), frames[0:3], iters, allocInterleavedSizes)
+	return checkAllocations(getMemProfileRecords(), leafFrame, frames[0:3], iters, allocInterleavedSizes)
 }
 
 var allocInterleavedSizes = []int64{17 * 1024, 1024, 18 * 1024, 512, 16 * 1024, 256}
@@ -108,22 +109,23 @@ func testSmallAllocations() error {
 	// Sizes of the allocations performed by each experiment.
 	sizes := []int64{1024, 512, 256}
 	frames := []string{"main.allocSmall1", "main.allocSmall2", "main.allocSmall3"}
+	leafFrame := "main.allocSmall"
 
 	// Pass if at least one of three experiments has no errors. Use a separate
 	// function for each experiment to identify each experiment in the profile.
 	allocSmall1(iters)
-	if checkAllocations(getMemProfileRecords(), frames[0:1], iters, sizes) == nil {
+	if checkAllocations(getMemProfileRecords(), leafFrame, frames[0:1], iters, sizes) == nil {
 		// Passed on first try, report no error.
 		return nil
 	}
 	allocSmall2(iters)
-	if checkAllocations(getMemProfileRecords(), frames[0:2], iters, sizes) == nil {
+	if checkAllocations(getMemProfileRecords(), leafFrame, frames[0:2], iters, sizes) == nil {
 		// Passed on second try, report no error.
 		return nil
 	}
 	allocSmall3(iters)
 	// If it fails a third time, we may be onto something.
-	return checkAllocations(getMemProfileRecords(), frames[0:3], iters, sizes)
+	return checkAllocations(getMemProfileRecords(), leafFrame, frames[0:3], iters, sizes)
 }
 
 // allocSmall performs only small allocations for sanity testing.
@@ -161,21 +163,21 @@ func allocSmall3(n int) {
 // Look only at samples that include the named frames, and group the
 // allocations by their line number. All these allocations are done from
 // the same leaf function, so their line numbers are the same.
-func checkAllocations(records []runtime.MemProfileRecord, frames []string, count int64, size []int64) error {
+func checkAllocations(records []runtime.MemProfileRecord, leafFrame string, frames []string, count int64, size []int64) error {
 	objectsPerLine := map[int][]int64{}
 	bytesPerLine := map[int][]int64{}
 	totalCount := []int64{}
 	// Compute the line number of the first allocation. All the
 	// allocations are from the same leaf, so pick the first one.
 	var firstLine int
-	for ln := range allocObjects(records, frames[0]) {
+	for ln := range allocObjects(records, leafFrame, frames[0]) {
 		if firstLine == 0 || firstLine > ln {
 			firstLine = ln
 		}
 	}
 	for _, frame := range frames {
 		var objectCount int64
-		a := allocObjects(records, frame)
+		a := allocObjects(records, leafFrame, frame)
 		for s := range size {
 			// Allocations of size size[s] should be on line firstLine + s.
 			ln := firstLine + s
@@ -258,7 +260,7 @@ type allocStat struct {
 // allocObjects examines the profile records for samples including the
 // named function and returns the allocation stats aggregated by
 // source line number of the allocation (at the leaf frame).
-func allocObjects(records []runtime.MemProfileRecord, function string) map[int]allocStat {
+func allocObjects(records []runtime.MemProfileRecord, leafFrame, function string) map[int]allocStat {
 	a := make(map[int]allocStat)
 	for _, r := range records {
 		var pcs []uintptr
@@ -273,7 +275,7 @@ func allocObjects(records []runtime.MemProfileRecord, function string) map[int]a
 		for {
 			frame, more := frames.Next()
 			name := frame.Function
-			if line == 0 {
+			if name == leafFrame && line == 0 {
 				line = frame.Line
 			}
 			if name == function {
diff --git a/test/live.go b/test/live.go
index 6e1a60557c8ad4..56b78ccf8b4af2 100644
--- a/test/live.go
+++ b/test/live.go
@@ -467,9 +467,9 @@ func f27defer(b bool) {
 func f27go(b bool) {
 	x := 0
 	if b {
-		go call27(func() { x++ }) // ERROR "live at call to newobject: &x$" "live at call to newobject: &x .autotmp_[0-9]+$" "live at call to newproc: &x$" // allocate two closures, the func literal, and the wrapper for go
+		go call27(func() { x++ }) // ERROR "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: &x$" "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: &x .autotmp_[0-9]+$" "live at call to newproc: &x$" // allocate two closures, the func literal, and the wrapper for go
 	}
-	go call27(func() { x++ }) // ERROR "live at call to newobject: &x$" "live at call to newobject: .autotmp_[0-9]+$" // allocate two closures, the func literal, and the wrapper for go
+	go call27(func() { x++ }) // ERROR "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: &x$" "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: .autotmp_[0-9]+$" // allocate two closures, the func literal, and the wrapper for go
 	printnl()
 }
 
@@ -538,7 +538,7 @@ func f31(b1, b2, b3 bool) {
 		g31(g18()) // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
 	}
 	if b2 {
-		h31(g18()) // ERROR "live at call to convT: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$"
+		h31(g18()) // ERROR "live at call to convT: .autotmp_[0-9]+$" "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: .autotmp_[0-9]+$"
 	}
 	if b3 {
 		panic(g18())
@@ -665,14 +665,14 @@ func f39a() (x []int) {
 
 func f39b() (x [10]*int) {
 	x = [10]*int{}
-	x[0] = new(int) // ERROR "live at call to newobject: x$"
+	x[0] = new(int) // ERROR "live at call to mallocTiny[48]: x$"
 	printnl()       // ERROR "live at call to printnl: x$"
 	return x
 }
 
 func f39c() (x [10]*int) {
 	x = [10]*int{}
-	x[0] = new(int) // ERROR "live at call to newobject: x$"
+	x[0] = new(int) // ERROR "live at call to mallocTiny[48]: x$"
 	printnl()       // ERROR "live at call to printnl: x$"
 	return
 }
diff --git a/test/live_regabi.go b/test/live_regabi.go
index d2565ba9130cd0..838cbdefad7c5b 100644
--- a/test/live_regabi.go
+++ b/test/live_regabi.go
@@ -465,9 +465,9 @@ func f27defer(b bool) {
 func f27go(b bool) {
 	x := 0
 	if b {
-		go call27(func() { x++ }) // ERROR "live at call to newobject: &x$" "live at call to newobject: &x .autotmp_[0-9]+$" "live at call to newproc: &x$" // allocate two closures, the func literal, and the wrapper for go
+		go call27(func() { x++ }) // ERROR "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: &x$" "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: &x .autotmp_[0-9]+$" "live at call to newproc: &x$" // allocate two closures, the func literal, and the wrapper for go
 	}
-	go call27(func() { x++ }) // ERROR "live at call to newobject: &x$" "live at call to newobject: .autotmp_[0-9]+$" // allocate two closures, the func literal, and the wrapper for go
+	go call27(func() { x++ }) // ERROR "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: &x$" "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: .autotmp_[0-9]+$" // allocate two closures, the func literal, and the wrapper for go
 	printnl()
 }
 
@@ -536,7 +536,7 @@ func f31(b1, b2, b3 bool) {
 		g31(g18()) // ERROR "stack object .autotmp_[0-9]+ \[2\]string$"
 	}
 	if b2 {
-		h31(g18()) // ERROR "live at call to convT: .autotmp_[0-9]+$" "live at call to newobject: .autotmp_[0-9]+$"
+		h31(g18()) // ERROR "live at call to convT: .autotmp_[0-9]+$" "live at call to mallocgcSmallScanNoHeaderSC[0-9]+: .autotmp_[0-9]+$"
 	}
 	if b3 {
 		panic(g18())
@@ -663,14 +663,14 @@ func f39a() (x []int) {
 
 func f39b() (x [10]*int) {
 	x = [10]*int{}
-	x[0] = new(int) // ERROR "live at call to newobject: x$"
+	x[0] = new(int) // ERROR "live at call to mallocTiny[48]: x$"
 	printnl()       // ERROR "live at call to printnl: x$"
 	return x
 }
 
 func f39c() (x [10]*int) {
 	x = [10]*int{}
-	x[0] = new(int) // ERROR "live at call to newobject: x$"
+	x[0] = new(int) // ERROR "live at call to mallocTiny[48]: x$"
 	printnl()       // ERROR "live at call to printnl: x$"
 	return
 }
diff --git a/test/uintptrescapes2.go b/test/uintptrescapes2.go
index 656286c0ff2bd7..e111d47fab95c4 100644
--- a/test/uintptrescapes2.go
+++ b/test/uintptrescapes2.go
@@ -33,8 +33,8 @@ func (T) M1(a uintptr) {} // ERROR "escaping uintptr"
 func (T) M2(a ...uintptr) {} // ERROR "escaping ...uintptr"
 
 func TestF1() {
-	var t int                        // ERROR "moved to heap"
-	F1(uintptr(unsafe.Pointer(&t)))  // ERROR "live at call to F1: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
+	var t int                       // ERROR "moved to heap"
+	F1(uintptr(unsafe.Pointer(&t))) // ERROR "live at call to F1: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
 }
 
 func TestF3() {
@@ -49,17 +49,17 @@ func TestM1() {
 }
 
 func TestF2() {
-	var v int                                 // ERROR "moved to heap"
-	F2(0, 1, uintptr(unsafe.Pointer(&v)), 2)  // ERROR "live at call to newobject: .?autotmp" "live at call to F2: .?autotmp" "escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
+	var v int                                // ERROR "moved to heap"
+	F2(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to mallocgcSmallNoScanSC[0-9]+: .?autotmp" "live at call to F2: .?autotmp" "escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
 }
 
 func TestF4() {
 	var v2 int                                // ERROR "moved to heap"
-	F4(0, 1, uintptr(unsafe.Pointer(&v2)), 2) // ERROR "live at call to newobject: .?autotmp" "live at call to F4: .?autotmp" "escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
+	F4(0, 1, uintptr(unsafe.Pointer(&v2)), 2) // ERROR "live at call to mallocgcSmallNoScanSC[0-9]+: .?autotmp" "live at call to F4: .?autotmp" "escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
 }
 
 func TestM2() {
 	var t T
 	var v int                                  // ERROR "moved to heap"
-	t.M2(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to newobject: .?autotmp" "live at call to T.M2: .?autotmp"  "escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
+	t.M2(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to mallocgcSmallNoScanSC[0-9]+: .?autotmp" "live at call to T.M2: .?autotmp"  "escapes to heap" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
 }

From 954fdcc51a678a2b84edb29ef4c3743b318a6fd8 Mon Sep 17 00:00:00 2001
From: WANG Xuerui 
Date: Thu, 9 Oct 2025 15:52:02 +0800
Subject: [PATCH 113/229] cmd/compile: declare no output register for loong64
 LoweredAtomic{And,Or}32 ops

The ICE seen on loong64 while compiling the `(*gcWork).tryStealSpan`
function was due to an `LoweredAtomicAnd32` op (inlined from the
`(pMask).clear` implementation) being incorrectly assigned an output
register while it shouldn't have. Because the op is of mem type, it has
needRegister() == false; hence in the shuffle phase of regalloc, its
bogus output register has no associated `orig` value recorded. The bug
was introduced in CL 482756, but only recently exposed by CL 696035.

Since the old-style atomic ops need no return value (and is even
documented so besides the loong64 ssa op definition), just fix the
register info for both.

While at it, add a note in the ssa op definition file about the
architectural necessity of resultNotInArgs for loong64 atomic ops,
because the practice is not seen in several other arches I have
checked.

Updates #75776

Change-Id: I087f51b8a2825d7b00fc3965b0afcc8b02cad277
Reviewed-on: https://go-review.googlesource.com/c/go/+/710475
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Pratt 
Reviewed-by: abner chenc 
Reviewed-by: Cherry Mui 
---
 src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go | 11 +++++++++--
 src/cmd/compile/internal/ssa/opGen.go           |  6 ------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go b/src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go
index a85a566660eee6..7e8b8bf497b8ff 100644
--- a/src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go
+++ b/src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go
@@ -143,6 +143,7 @@ func init() {
 		gp2load   = regInfo{inputs: []regMask{gpspsbg, gpg}, outputs: []regMask{gp}}
 		gpstore   = regInfo{inputs: []regMask{gpspsbg, gpg}}
 		gpstore2  = regInfo{inputs: []regMask{gpspsbg, gpg, gpg | rz}}
+		gpoldatom = regInfo{inputs: []regMask{gpspsbg, gpg}}
 		gpxchg    = regInfo{inputs: []regMask{gpspsbg, gpg}, outputs: []regMask{gp}}
 		gpcas     = regInfo{inputs: []regMask{gpspsbg, gpg, gpg}, outputs: []regMask{gp}}
 		preldreg  = regInfo{inputs: []regMask{gpspg}}
@@ -431,6 +432,12 @@ func init() {
 			faultOnNilArg1: true,
 		},
 
+		// Atomic operations.
+		//
+		// resultNotInArgs is needed by all ops lowering to LoongArch
+		// atomic memory access instructions, because these instructions
+		// are defined to require rd != rj && rd != rk per the ISA spec.
+
 		// atomic loads.
 		// load from arg0. arg1=mem.
 		// returns  so they can be properly ordered with other loads.
@@ -500,8 +507,8 @@ func init() {
 
 		// Atomic 32 bit AND/OR.
 		// *arg0 &= (|=) arg1. arg2=mem. returns nil.
-		{name: "LoweredAtomicAnd32", argLength: 3, reg: gpxchg, asm: "AMANDDBW", resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
-		{name: "LoweredAtomicOr32", argLength: 3, reg: gpxchg, asm: "AMORDBW", resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
+		{name: "LoweredAtomicAnd32", argLength: 3, reg: gpoldatom, asm: "AMANDDBW", resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
+		{name: "LoweredAtomicOr32", argLength: 3, reg: gpoldatom, asm: "AMORDBW", resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
 
 		// Atomic 32,64 bit AND/OR.
 		// *arg0 &= (|=) arg1. arg2=mem. returns . auxint must be zero.
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 32ba3a89856ed4..3ed1619e4a6ab9 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -26392,9 +26392,6 @@ var opcodeTable = [...]opInfo{
 				{1, 1073741816},          // R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 g R23 R24 R25 R26 R27 R28 R29 R31
 				{0, 4611686019501129724}, // SP R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 g R23 R24 R25 R26 R27 R28 R29 R31 SB
 			},
-			outputs: []outputInfo{
-				{0, 1071644664}, // R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R23 R24 R25 R26 R27 R28 R29 R31
-			},
 		},
 	},
 	{
@@ -26409,9 +26406,6 @@ var opcodeTable = [...]opInfo{
 				{1, 1073741816},          // R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 g R23 R24 R25 R26 R27 R28 R29 R31
 				{0, 4611686019501129724}, // SP R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 g R23 R24 R25 R26 R27 R28 R29 R31 SB
 			},
-			outputs: []outputInfo{
-				{0, 1071644664}, // R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R23 R24 R25 R26 R27 R28 R29 R31
-			},
 		},
 	},
 	{

From c53cb642deea152e28281133bc0053f5ec0ce358 Mon Sep 17 00:00:00 2001
From: WANG Xuerui 
Date: Thu, 9 Oct 2025 16:05:35 +0800
Subject: [PATCH 114/229] internal/buildcfg: enable greenteagc experiment for
 loong64

The loong64 compiler bug has been resolved, so we can now
unconditionally enable the experiment on the architecture.

Updates #73581
Fixes #75776

Change-Id: I390f8a125d43ca64798ea5b6a408aaf7220fadbf
Reviewed-on: https://go-review.googlesource.com/c/go/+/710476
Reviewed-by: Michael Knyszek 
Auto-Submit: abner chenc 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: abner chenc 
Reviewed-by: Cherry Mui 
---
 src/internal/buildcfg/exp.go | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/src/internal/buildcfg/exp.go b/src/internal/buildcfg/exp.go
index fb6b5859e31a1e..f1a1d8632ef507 100644
--- a/src/internal/buildcfg/exp.go
+++ b/src/internal/buildcfg/exp.go
@@ -78,18 +78,13 @@ func ParseGOEXPERIMENT(goos, goarch, goexp string) (*ExperimentFlags, error) {
 	// things like .debug_addr (needed for DWARF 5).
 	dwarf5Supported := (goos != "darwin" && goos != "ios" && goos != "aix")
 
-	// The compiler crashes while compiling some of the Green Tea code.
-	// The Green Tea code is pretty normal, so this is likely a compiler
-	// bug in the loong64 port.
-	greenTeaGCSupported := goarch != "loong64"
-
 	baseline := goexperiment.Flags{
 		RegabiWrappers:        regabiSupported,
 		RegabiArgs:            regabiSupported,
 		Dwarf5:                dwarf5Supported,
 		RandomizedHeapBase64:  true,
 		SizeSpecializedMalloc: true,
-		GreenTeaGC:            greenTeaGCSupported,
+		GreenTeaGC:            true,
 	}
 
 	// Start with the statically enabled set of experiments.

From 5368e7742971c8dbcb75a405eb2319e71fb1d0c7 Mon Sep 17 00:00:00 2001
From: Damien Neil 
Date: Thu, 9 Oct 2025 15:25:30 -0700
Subject: [PATCH 115/229] net/http: run TestRequestWriteTransport with fake
 time to avoid flakes

This test verifies whether or not we use the chunked encoding when
sending a request with a body like io.NopCloser(strings.NewReader("")).
This depends on whether the transport can read a single byte from the
request body within 200ms, which is flaky on very slow builders.

Use fake time to avoid flakes.

Fixes #52575

Change-Id: Ie11a58ac6bc18d43af1423827887e804242dee30
Reviewed-on: https://go-review.googlesource.com/c/go/+/710737
Auto-Submit: Nicholas Husin 
Reviewed-by: Nicholas Husin 
Reviewed-by: Nicholas Husin 
LUCI-TryBot-Result: Go LUCI 
---
 src/net/http/requestwrite_test.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/net/http/requestwrite_test.go b/src/net/http/requestwrite_test.go
index 380ae9dec3244d..8b097cd5e15d1f 100644
--- a/src/net/http/requestwrite_test.go
+++ b/src/net/http/requestwrite_test.go
@@ -15,6 +15,7 @@ import (
 	"strings"
 	"testing"
 	"testing/iotest"
+	"testing/synctest"
 	"time"
 )
 
@@ -667,6 +668,13 @@ func TestRequestWrite(t *testing.T) {
 func TestRequestWriteTransport(t *testing.T) {
 	t.Parallel()
 
+	// Run this test in a synctest bubble, since it relies on the transport
+	// successfully probing the request body within 200ms
+	// (see transferWriter.probeRequestBody).
+	// This occasionally flakes on slow builders (#52575) if we don't use a fake clock.
+	synctest.Test(t, testRequestWriteTransport)
+}
+func testRequestWriteTransport(t *testing.T) {
 	matchSubstr := func(substr string) func(string) error {
 		return func(written string) error {
 			if !strings.Contains(written, substr) {

From 955a5a0dc5dd68ed89200a08f17590c0a94c1e09 Mon Sep 17 00:00:00 2001
From: Julia Lapenko 
Date: Wed, 13 Aug 2025 22:23:14 +0300
Subject: [PATCH 116/229] runtime: support arm64 Neon in async preemption

This is a port of CL 669195 adjusted to save arm64 Neon registers
off stack.

Change-Id: Ia014778a8c9f0c1d05977b04184f51e791ae8495
Reviewed-on: https://go-review.googlesource.com/c/go/+/695916
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Mark Freeman 
Reviewed-by: Cherry Mui 
---
 src/runtime/mkpreempt.go      | 204 +++++++++++++++++++++++++++-------
 src/runtime/preempt_arm64.go  |  38 +++++++
 src/runtime/preempt_arm64.s   |  66 +++++------
 src/runtime/preempt_noxreg.go |   2 +-
 src/runtime/preempt_xreg.go   |   2 +-
 5 files changed, 236 insertions(+), 76 deletions(-)
 create mode 100644 src/runtime/preempt_arm64.go

diff --git a/src/runtime/mkpreempt.go b/src/runtime/mkpreempt.go
index 769c4ffc5c9eeb..7b84ba0a6fbaaf 100644
--- a/src/runtime/mkpreempt.go
+++ b/src/runtime/mkpreempt.go
@@ -163,19 +163,21 @@ package runtime
 type xRegs struct {
 `)
 	pos := 0
-	for _, reg := range l.regs {
-		if reg.pos != pos {
-			log.Fatalf("padding not implemented")
-		}
-		typ := fmt.Sprintf("[%d]byte", reg.size)
-		switch {
-		case reg.size == 4 && reg.pos%4 == 0:
-			typ = "uint32"
-		case reg.size == 8 && reg.pos%8 == 0:
-			typ = "uint64"
+	for _, seq := range l.regs {
+		for _, r := range seq.regs {
+			if r.pos != pos && !seq.fixedOffset {
+				log.Fatalf("padding not implemented")
+			}
+			typ := fmt.Sprintf("[%d]byte", r.size)
+			switch {
+			case r.size == 4 && r.pos%4 == 0:
+				typ = "uint32"
+			case r.size == 8 && r.pos%8 == 0:
+				typ = "uint64"
+			}
+			fmt.Fprintf(g.w, "\t%s %s\n", r.name, typ)
+			pos += r.size
 		}
-		fmt.Fprintf(g.w, "\t%s %s\n", reg.reg, typ)
-		pos += reg.size
 	}
 	fmt.Fprintf(g.w, "}\n")
 
@@ -191,16 +193,61 @@ type xRegs struct {
 
 type layout struct {
 	stack int
-	regs  []regPos
+	regs  []regSeq
 	sp    string // stack pointer register
 }
 
-type regPos struct {
-	pos, size int
+type regInfo struct {
+	size int    // register size in bytes
+	name string // register name
+
+	// Some register names may require a specific suffix.
+	// In ARM64, a suffix called an "arrangement specifier" can be added to
+	// a register name. For example:
+	//
+	//	V0.B16
+	//
+	// In this case, "V0" is the register name, and ".B16" is the suffix.
+	suffix string
 
+	pos int // position on stack
+}
+
+// Some save/restore operations can involve multiple registers in a single
+// instruction. For example, the LDP/STP instructions in ARM64:
+//
+//	LDP 8(RSP), (R0, R1)
+//	STP (R0, R1), 8(RSP)
+//
+// In these cases, a pair of registers (R0, R1) is used as a single argument.
+type regSeq struct {
 	saveOp    string
 	restoreOp string
-	reg       string
+	regs      []regInfo
+
+	// By default, all registers are saved on the stack, and the stack pointer offset
+	// is calculated based on the size of each register. For example (ARM64):
+	//
+	//   STP (R0, R1), 8(RSP)
+	//   STP (R2, R3), 24(RSP)
+	//
+	// However, automatic offset calculation may not always be desirable.
+	// In some cases, the offset must remain fixed:
+	//
+	//   VST1.P [V0.B16, V1.B16, V2.B16, V3.B16], 64(R0)
+	//   VST1.P [V4.B16, V5.B16, V6.B16, V7.B16], 64(R0)
+	//
+	// In this example, R0 is post-incremented after each instruction,
+	// so the offset should not be recalculated. For such cases,
+	// `fixedOffset` is set to true.
+	fixedOffset bool
+
+	// After conversion to a string, register names are separated by commas
+	// and may be wrapped in a custom pair of brackets. For example (ARM64):
+	//
+	//   (R0, R1) // wrapped in parentheses
+	//   [V0.B16, V1.B16, V2.B16, V3.B16] // wrapped in square brackets
+	brackets [2]string
 
 	// If this register requires special save and restore, these
 	// give those operations with a %d placeholder for the stack
@@ -208,42 +255,97 @@ type regPos struct {
 	save, restore string
 }
 
-func (l *layout) add(op, reg string, size int) {
-	l.regs = append(l.regs, regPos{saveOp: op, restoreOp: op, reg: reg, pos: l.stack, size: size})
+func (l *layout) add(op, regname string, size int) {
+	l.regs = append(l.regs, regSeq{saveOp: op, restoreOp: op, regs: []regInfo{{size, regname, "", l.stack}}})
 	l.stack += size
 }
 
-func (l *layout) add2(sop, rop, reg string, size int) {
-	l.regs = append(l.regs, regPos{saveOp: sop, restoreOp: rop, reg: reg, pos: l.stack, size: size})
-	l.stack += size
+func (l *layout) add2(sop, rop string, regs []regInfo, brackets [2]string, fixedOffset bool) {
+	l.regs = append(l.regs, regSeq{saveOp: sop, restoreOp: rop, regs: regs, brackets: brackets, fixedOffset: fixedOffset})
+	if !fixedOffset {
+		for i := range regs {
+			regs[i].pos = l.stack
+			l.stack += regs[i].size
+		}
+	}
 }
 
 func (l *layout) addSpecial(save, restore string, size int) {
-	l.regs = append(l.regs, regPos{save: save, restore: restore, pos: l.stack, size: size})
+	l.regs = append(l.regs, regSeq{save: save, restore: restore, regs: []regInfo{{size, "", "", l.stack}}})
 	l.stack += size
 }
 
+func (rs *regSeq) String() string {
+	switch len(rs.regs) {
+	case 0:
+		log.Fatal("Register sequence must not be empty!")
+	case 1:
+		return rs.regs[0].name
+	default:
+		names := make([]string, 0)
+		for _, r := range rs.regs {
+			name := r.name + r.suffix
+			names = append(names, name)
+		}
+		return rs.brackets[0] + strings.Join(names, ", ") + rs.brackets[1]
+	}
+	return ""
+}
+
 func (l *layout) save(g *gen) {
-	for _, reg := range l.regs {
-		if reg.save != "" {
-			g.p(reg.save, reg.pos)
+	for _, seq := range l.regs {
+		if len(seq.regs) < 1 {
+			log.Fatal("Register sequence must not be empty!")
+		}
+		// When dealing with a sequence of registers, we assume that only the position
+		// of the first register is relevant. For example:
+		//
+		//   STP (R0, R1), 8(RSP)
+		//   STP (R2, R3), 24(RSP)
+		//
+		// Here, R0.pos is 8. While we can infer that R1.pos is 16, it doesn't need to
+		// be explicitly specified, as the STP instruction calculates it automatically.
+		pos := seq.regs[0].pos
+		if seq.save != "" {
+			g.p(seq.save, pos)
 		} else {
-			g.p("%s %s, %d(%s)", reg.saveOp, reg.reg, reg.pos, l.sp)
+			name := seq.String()
+			g.p("%s %s, %d(%s)", seq.saveOp, name, pos, l.sp)
 		}
 	}
 }
 
-func (l *layout) restore(g *gen) {
-	for i := len(l.regs) - 1; i >= 0; i-- {
-		reg := l.regs[i]
+func (l *layout) restoreInOrder(g *gen, reverse bool) {
+	var seq []regSeq
+	if reverse {
+		seq = make([]regSeq, 0)
+		for i := len(l.regs) - 1; i >= 0; i-- {
+			seq = append(seq, l.regs[i])
+		}
+	} else {
+		seq = l.regs
+	}
+	for _, reg := range seq {
+		if len(reg.regs) < 1 {
+			log.Fatal("Register sequence must not be empty!")
+		}
+		pos := reg.regs[0].pos
 		if reg.restore != "" {
-			g.p(reg.restore, reg.pos)
+			g.p(reg.restore, pos)
 		} else {
-			g.p("%s %d(%s), %s", reg.restoreOp, reg.pos, l.sp, reg.reg)
+			g.p("%s %d(%s), %s", reg.restoreOp, pos, l.sp, reg.String())
 		}
 	}
 }
 
+func (l *layout) restore(g *gen) {
+	l.restoreInOrder(g, true)
+}
+
+func (l *layout) restoreDirect(g *gen) {
+	l.restoreInOrder(g, false)
+}
+
 func gen386(g *gen) {
 	p := g.p
 
@@ -320,8 +422,11 @@ func genAMD64(g *gen) {
 	// We don't have to do this, but it results in a nice Go type. If we split
 	// this into multiple types, we probably should stop doing this.
 	for i := range lXRegs.regs {
-		lXRegs.regs[i].pos = lZRegs.regs[i].pos
-		lYRegs.regs[i].pos = lZRegs.regs[i].pos
+		for j := range lXRegs.regs[i].regs {
+			lXRegs.regs[i].regs[j].pos = lZRegs.regs[i].regs[j].pos
+			lYRegs.regs[i].regs[j].pos = lZRegs.regs[i].regs[j].pos
+		}
+
 	}
 	writeXRegs(g.goarch, &lZRegs)
 
@@ -456,6 +561,7 @@ func genARM(g *gen) {
 }
 
 func genARM64(g *gen) {
+	const vReg = "R0" // *xRegState
 	p := g.p
 	// Add integer registers R0-R26
 	// R27 (REGTMP), R28 (g), R29 (FP), R30 (LR), R31 (SP) are special
@@ -466,8 +572,11 @@ func genARM64(g *gen) {
 			i--
 			continue // R18 is not used, skip
 		}
-		reg := fmt.Sprintf("(R%d, R%d)", i, i+1)
-		l.add2("STP", "LDP", reg, 16)
+		regs := []regInfo{
+			{name: fmt.Sprintf("R%d", i), size: 8},
+			{name: fmt.Sprintf("R%d", i+1), size: 8},
+		}
+		l.add2("STP", "LDP", regs, [2]string{"(", ")"}, false)
 	}
 	// Add flag registers.
 	l.addSpecial(
@@ -480,10 +589,17 @@ func genARM64(g *gen) {
 		8)
 	// TODO: FPCR? I don't think we'll change it, so no need to save.
 	// Add floating point registers F0-F31.
-	for i := 0; i < 31; i += 2 {
-		reg := fmt.Sprintf("(F%d, F%d)", i, i+1)
-		l.add2("FSTPD", "FLDPD", reg, 16)
+	lVRegs := layout{sp: vReg} // Non-GP registers
+	for i := 0; i < 31; i += 4 {
+		regs := []regInfo{
+			{name: fmt.Sprintf("V%d", i), suffix: ".B16", size: 16, pos: 64},
+			{name: fmt.Sprintf("V%d", i+1), suffix: ".B16", size: 16, pos: 64},
+			{name: fmt.Sprintf("V%d", i+2), suffix: ".B16", size: 16, pos: 64},
+			{name: fmt.Sprintf("V%d", i+3), suffix: ".B16", size: 16, pos: 64},
+		}
+		lVRegs.add2("VST1.P", "VLD1.P", regs, [2]string{"[", "]"}, true)
 	}
+	writeXRegs(g.goarch, &lVRegs)
 	if l.stack%16 != 0 {
 		l.stack += 8 // SP needs 16-byte alignment
 	}
@@ -500,8 +616,20 @@ func genARM64(g *gen) {
 	p("MOVD R30, (RSP)")
 	p("#endif")
 
+	p("// Save GPs")
 	l.save(g)
+	p("// Save extended register state to p.xRegs.scratch")
+	p("MOVD g_m(g), %s", vReg)
+	p("MOVD m_p(%s), %s", vReg, vReg)
+	p("ADD $(p_xRegs+xRegPerP_scratch), %s, %s", vReg, vReg)
+	lVRegs.save(g)
 	p("CALL ·asyncPreempt2(SB)")
+	p("// Restore non-GPs from *p.xRegs.cache")
+	p("MOVD g_m(g), %s", vReg)
+	p("MOVD m_p(%s), %s", vReg, vReg)
+	p("MOVD (p_xRegs+xRegPerP_cache)(%s), %s", vReg, vReg)
+	lVRegs.restoreDirect(g)
+	p("// Restore GPs")
 	l.restore(g)
 
 	p("MOVD %d(RSP), R30", l.stack) // sigctxt.pushCall has pushed LR (at interrupt) on stack, restore it
diff --git a/src/runtime/preempt_arm64.go b/src/runtime/preempt_arm64.go
new file mode 100644
index 00000000000000..1b71d2713ea5d0
--- /dev/null
+++ b/src/runtime/preempt_arm64.go
@@ -0,0 +1,38 @@
+// Code generated by mkpreempt.go; DO NOT EDIT.
+
+package runtime
+
+type xRegs struct {
+	V0  [16]byte
+	V1  [16]byte
+	V2  [16]byte
+	V3  [16]byte
+	V4  [16]byte
+	V5  [16]byte
+	V6  [16]byte
+	V7  [16]byte
+	V8  [16]byte
+	V9  [16]byte
+	V10 [16]byte
+	V11 [16]byte
+	V12 [16]byte
+	V13 [16]byte
+	V14 [16]byte
+	V15 [16]byte
+	V16 [16]byte
+	V17 [16]byte
+	V18 [16]byte
+	V19 [16]byte
+	V20 [16]byte
+	V21 [16]byte
+	V22 [16]byte
+	V23 [16]byte
+	V24 [16]byte
+	V25 [16]byte
+	V26 [16]byte
+	V27 [16]byte
+	V28 [16]byte
+	V29 [16]byte
+	V30 [16]byte
+	V31 [16]byte
+}
diff --git a/src/runtime/preempt_arm64.s b/src/runtime/preempt_arm64.s
index 31ec9d940f76d4..9017d8815970b2 100644
--- a/src/runtime/preempt_arm64.s
+++ b/src/runtime/preempt_arm64.s
@@ -4,13 +4,14 @@
 #include "textflag.h"
 
 TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
-	MOVD R30, -496(RSP)
-	SUB $496, RSP
+	MOVD R30, -240(RSP)
+	SUB $240, RSP
 	MOVD R29, -8(RSP)
 	SUB $8, RSP, R29
 	#ifdef GOOS_ios
 	MOVD R30, (RSP)
 	#endif
+	// Save GPs
 	STP (R0, R1), 8(RSP)
 	STP (R2, R3), 24(RSP)
 	STP (R4, R5), 40(RSP)
@@ -28,39 +29,32 @@ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
 	MOVD R0, 216(RSP)
 	MOVD FPSR, R0
 	MOVD R0, 224(RSP)
-	FSTPD (F0, F1), 232(RSP)
-	FSTPD (F2, F3), 248(RSP)
-	FSTPD (F4, F5), 264(RSP)
-	FSTPD (F6, F7), 280(RSP)
-	FSTPD (F8, F9), 296(RSP)
-	FSTPD (F10, F11), 312(RSP)
-	FSTPD (F12, F13), 328(RSP)
-	FSTPD (F14, F15), 344(RSP)
-	FSTPD (F16, F17), 360(RSP)
-	FSTPD (F18, F19), 376(RSP)
-	FSTPD (F20, F21), 392(RSP)
-	FSTPD (F22, F23), 408(RSP)
-	FSTPD (F24, F25), 424(RSP)
-	FSTPD (F26, F27), 440(RSP)
-	FSTPD (F28, F29), 456(RSP)
-	FSTPD (F30, F31), 472(RSP)
+	// Save extended register state to p.xRegs.scratch
+	MOVD g_m(g), R0
+	MOVD m_p(R0), R0
+	ADD $(p_xRegs+xRegPerP_scratch), R0, R0
+	VST1.P [V0.B16, V1.B16, V2.B16, V3.B16], 64(R0)
+	VST1.P [V4.B16, V5.B16, V6.B16, V7.B16], 64(R0)
+	VST1.P [V8.B16, V9.B16, V10.B16, V11.B16], 64(R0)
+	VST1.P [V12.B16, V13.B16, V14.B16, V15.B16], 64(R0)
+	VST1.P [V16.B16, V17.B16, V18.B16, V19.B16], 64(R0)
+	VST1.P [V20.B16, V21.B16, V22.B16, V23.B16], 64(R0)
+	VST1.P [V24.B16, V25.B16, V26.B16, V27.B16], 64(R0)
+	VST1.P [V28.B16, V29.B16, V30.B16, V31.B16], 64(R0)
 	CALL ·asyncPreempt2(SB)
-	FLDPD 472(RSP), (F30, F31)
-	FLDPD 456(RSP), (F28, F29)
-	FLDPD 440(RSP), (F26, F27)
-	FLDPD 424(RSP), (F24, F25)
-	FLDPD 408(RSP), (F22, F23)
-	FLDPD 392(RSP), (F20, F21)
-	FLDPD 376(RSP), (F18, F19)
-	FLDPD 360(RSP), (F16, F17)
-	FLDPD 344(RSP), (F14, F15)
-	FLDPD 328(RSP), (F12, F13)
-	FLDPD 312(RSP), (F10, F11)
-	FLDPD 296(RSP), (F8, F9)
-	FLDPD 280(RSP), (F6, F7)
-	FLDPD 264(RSP), (F4, F5)
-	FLDPD 248(RSP), (F2, F3)
-	FLDPD 232(RSP), (F0, F1)
+	// Restore non-GPs from *p.xRegs.cache
+	MOVD g_m(g), R0
+	MOVD m_p(R0), R0
+	MOVD (p_xRegs+xRegPerP_cache)(R0), R0
+	VLD1.P 64(R0), [V0.B16, V1.B16, V2.B16, V3.B16]
+	VLD1.P 64(R0), [V4.B16, V5.B16, V6.B16, V7.B16]
+	VLD1.P 64(R0), [V8.B16, V9.B16, V10.B16, V11.B16]
+	VLD1.P 64(R0), [V12.B16, V13.B16, V14.B16, V15.B16]
+	VLD1.P 64(R0), [V16.B16, V17.B16, V18.B16, V19.B16]
+	VLD1.P 64(R0), [V20.B16, V21.B16, V22.B16, V23.B16]
+	VLD1.P 64(R0), [V24.B16, V25.B16, V26.B16, V27.B16]
+	VLD1.P 64(R0), [V28.B16, V29.B16, V30.B16, V31.B16]
+	// Restore GPs
 	MOVD 224(RSP), R0
 	MOVD R0, FPSR
 	MOVD 216(RSP), R0
@@ -78,8 +72,8 @@ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
 	LDP 40(RSP), (R4, R5)
 	LDP 24(RSP), (R2, R3)
 	LDP 8(RSP), (R0, R1)
-	MOVD 496(RSP), R30
+	MOVD 240(RSP), R30
 	MOVD -8(RSP), R29
 	MOVD (RSP), R27
-	ADD $512, RSP
+	ADD $256, RSP
 	RET (R27)
diff --git a/src/runtime/preempt_noxreg.go b/src/runtime/preempt_noxreg.go
index dfe46559b5b723..9f03b2b333420e 100644
--- a/src/runtime/preempt_noxreg.go
+++ b/src/runtime/preempt_noxreg.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !amd64
+//go:build !amd64 && !arm64
 
 // This provides common support for architectures that DO NOT use extended
 // register state in asynchronous preemption.
diff --git a/src/runtime/preempt_xreg.go b/src/runtime/preempt_xreg.go
index 9e05455ddbb747..f4578a4d76d889 100644
--- a/src/runtime/preempt_xreg.go
+++ b/src/runtime/preempt_xreg.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build amd64
+//go:build amd64 || arm64
 
 // This provides common support for architectures that use extended register
 // state in asynchronous preemption.

From 6f4c63ba63fdec6e4a42e2e19ac71937973dedef Mon Sep 17 00:00:00 2001
From: Alan Donovan 
Date: Fri, 26 Sep 2025 13:33:09 -0400
Subject: [PATCH 117/229] cmd/go: unify "go fix" and "go vet"

This change unifies the fix and vet subcommands; they use the
same run function, action graph, and external tool (-vettool
for go vet and -fixtool for go fix). go fix runs the tool
with the -fix flag, whereas although go vet also supports
-fix, it is not the default. The two tools have different
(overlapping) suites of analyzers.

The high-level parts are fully parameterized over the
vet/fix distinction; the lower-level parts (the action
graph) continue to use only the "vet" terminology.
The cmd/{vet,fix} executable is referred to as the "tool".

The tool is generally invoked in -json mode, regardless
of whether -json was requested, so that the tool produces
a cacheable JSON blob on stdout. When the go user did not
request -json, this blob is parsed and printed to stderr
by logic in the go vet command. (Formerly the tool would
print diagnostics to stderr, but this interacts poorly
with the build cache.)

go fix's legacy -fix=fixer,... flag is now a no-op that
prints a warning that the flag is obsolete.

The unitchecker's -c=n flag (to display n lines of context
around each diagnostic) is reimplemented in go vet based
on the JSON information, to avoid reliance on the stderr
output of the tool.

cmd/fix is added to dist's prebuilt set of tools since
go fix cannot build it dynamically (though ideally
it would).

Updates #71859
For #75432

Change-Id: I0a84746720b59d05d662ed57826747c5598dca44
Reviewed-on: https://go-review.googlesource.com/c/go/+/700795
Reviewed-by: Michael Matloob 
Auto-Submit: Alan Donovan 
Reviewed-by: Michael Matloob 
TryBot-Bypass: Alan Donovan 
---
 doc/next/3-tools.md                      |  10 +
 src/cmd/dist/build.go                    |   2 +-
 src/cmd/fix/doc.go                       |  20 --
 src/cmd/fix/main.go                      |  66 ++--
 src/cmd/go/alldocs.go                    |  60 ++--
 src/cmd/go/internal/fix/fix.go           |  86 ------
 src/cmd/go/internal/test/test.go         |   1 +
 src/cmd/go/internal/vet/vet.go           | 371 +++++++++++++++++++++--
 src/cmd/go/internal/vet/vetflag.go       | 170 ++++++-----
 src/cmd/go/internal/work/buildid.go      |   7 +-
 src/cmd/go/internal/work/exec.go         |  81 +++--
 src/cmd/go/main.go                       |   3 +-
 src/cmd/go/testdata/script/chdir.txt     |   4 +
 src/cmd/go/testdata/script/vet_asm.txt   |   8 +-
 src/cmd/go/testdata/script/vet_basic.txt | 125 ++++++++
 src/cmd/go/testdata/script/vet_cache.txt |  24 ++
 src/cmd/vet/doc.go                       |   2 +
 src/cmd/vet/main.go                      |  91 +++---
 src/cmd/vet/testdata/print/print.go      |   2 +-
 src/cmd/vet/vet_test.go                  |  16 +-
 20 files changed, 818 insertions(+), 331 deletions(-)
 delete mode 100644 src/cmd/fix/doc.go
 delete mode 100644 src/cmd/go/internal/fix/fix.go
 create mode 100644 src/cmd/go/testdata/script/vet_basic.txt
 create mode 100644 src/cmd/go/testdata/script/vet_cache.txt

diff --git a/doc/next/3-tools.md b/doc/next/3-tools.md
index 9459a5490e7904..c0a4601c0b9e74 100644
--- a/doc/next/3-tools.md
+++ b/doc/next/3-tools.md
@@ -7,5 +7,15 @@
 a replacement for `go tool doc`: it takes the same flags and arguments and
 has the same behavior.
 
+
+The `go fix` command, following the pattern of `go vet` in Go 1.10,
+now uses the Go analysis framework (`golang.org/x/tools/go/analysis`).
+This means the same analyzers that provide diagnostics in `go vet`
+can be used to suggest and apply fixes in `go fix`.
+The `go fix` command's historical fixers, all of which were obsolete,
+have been removed and replaced by a suite of new analyzers that
+offer fixes to use newer features of the language and library.
+
+
 ### Cgo {#cgo}
 
diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index 9a7951726f6f04..2fcdb2d3915b9b 100644
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -1397,7 +1397,7 @@ var (
 	binExesIncludedInDistpack = []string{"cmd/go", "cmd/gofmt"}
 
 	// Keep in sync with the filter in cmd/distpack/pack.go.
-	toolsIncludedInDistpack = []string{"cmd/asm", "cmd/cgo", "cmd/compile", "cmd/cover", "cmd/link", "cmd/preprofile", "cmd/vet"}
+	toolsIncludedInDistpack = []string{"cmd/asm", "cmd/cgo", "cmd/compile", "cmd/cover", "cmd/fix", "cmd/link", "cmd/preprofile", "cmd/vet"}
 
 	// We could install all tools in "cmd", but is unnecessary because we will
 	// remove them in distpack, so instead install the tools that will actually
diff --git a/src/cmd/fix/doc.go b/src/cmd/fix/doc.go
deleted file mode 100644
index b3d69144717172..00000000000000
--- a/src/cmd/fix/doc.go
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-/*
-Fix finds Go programs that use old APIs and rewrites them to use
-newer ones.  After you update to a new Go release, fix helps make
-the necessary changes to your programs.
-
-Usage:
-
-	go tool fix [ignored...]
-
-This tool is currently in transition. All its historical fixers were
-long obsolete and have been removed, so it is currently a no-op. In
-due course the tool will integrate with the Go analysis framework
-(golang.org/x/tools/go/analysis) and run a modern suite of fix
-algorithms; see https://go.dev/issue/71859.
-*/
-package main
diff --git a/src/cmd/fix/main.go b/src/cmd/fix/main.go
index 87cc0d6414601b..422fa827459900 100644
--- a/src/cmd/fix/main.go
+++ b/src/cmd/fix/main.go
@@ -1,31 +1,59 @@
-// Copyright 2011 The Go Authors. All rights reserved.
+// Copyright 2025 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+/*
+Fix is a tool executed by "go fix" to update Go programs that use old
+features of the language and library and rewrite them to use newer
+ones. After you update to a new Go release, fix helps make the
+necessary changes to your programs.
+
+See the documentation for "go fix" for how to run this command.
+You can provide an alternative tool using "go fix -fixtool=..."
+
+Run "go tool fix help" to see the list of analyzers supported by this
+program.
+
+See [golang.org/x/tools/go/analysis] for information on how to write
+an analyzer that can suggest fixes.
+*/
 package main
 
 import (
-	"flag"
-	"fmt"
-	"os"
-)
+	"cmd/internal/objabi"
+	"cmd/internal/telemetry/counter"
 
-var (
-	_ = flag.Bool("diff", false, "obsolete, no effect")
-	_ = flag.String("go", "", "obsolete, no effect")
-	_ = flag.String("r", "", "obsolete, no effect")
-	_ = flag.String("force", "", "obsolete, no effect")
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/buildtag"
+	"golang.org/x/tools/go/analysis/passes/hostport"
+	"golang.org/x/tools/go/analysis/unitchecker"
 )
 
-func usage() {
-	fmt.Fprintf(os.Stderr, "usage: go tool fix [-diff] [-r ignored] [-force ignored] ...\n")
-	flag.PrintDefaults()
-	os.Exit(2)
-}
-
 func main() {
-	flag.Usage = usage
-	flag.Parse()
+	// Keep consistent with cmd/vet/main.go!
+	counter.Open()
+	objabi.AddVersionFlag()
+	counter.Inc("fix/invocations")
+
+	unitchecker.Main(suite...) // (never returns)
+}
 
-	os.Exit(0)
+// The fix suite analyzers produce fixes that are safe to apply.
+// (Diagnostics may not describe actual problems,
+// but their fixes must be unambiguously safe to apply.)
+var suite = []*analysis.Analyzer{
+	buildtag.Analyzer,
+	hostport.Analyzer,
+	// TODO(adonovan): now the modernize (proposal #75266) and
+	// inline (proposal #75267) analyzers are published, revendor
+	// x/tools and add them here.
+	//
+	// TODO(adonovan):add any other vet analyzers whose fixes are always safe.
+	// Candidates to audit: sigchanyzer, printf, assign, unreachable.
+	// Rejected:
+	// - composites: some types (e.g. PointXY{1,2}) don't want field names.
+	// - timeformat: flipping MM/DD is a behavior change, but the code
+	//    could potentially be a workaround for another bug.
+	// - stringintconv: offers two fixes, user input required to choose.
+	// - fieldalignment: poor signal/noise; fix could be a regression.
 }
diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 51f2223283b175..67c0ecbe8b2fcf 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -18,7 +18,7 @@
 //	clean       remove object files and cached files
 //	doc         show documentation for package or symbol
 //	env         print Go environment information
-//	fix         update packages to use new APIs
+//	fix         apply fixes suggested by static checkers
 //	fmt         gofmt (reformat) package sources
 //	generate    generate Go files by processing source
 //	get         add dependencies to current module and install them
@@ -495,22 +495,34 @@
 //
 // For more about environment variables, see 'go help environment'.
 //
-// # Update packages to use new APIs
+// # Apply fixes suggested by static checkers
 //
 // Usage:
 //
-//	go fix [-fix list] [packages]
+//	go fix [build flags] [-fixtool prog] [fix flags] [packages]
 //
-// Fix runs the Go fix command on the packages named by the import paths.
+// Fix runs the Go fix tool (cmd/vet) on the named packages
+// and applies suggested fixes.
 //
-// The -fix flag sets a comma-separated list of fixes to run.
-// The default is all known fixes.
-// (Its value is passed to 'go tool fix -r'.)
+// It supports these flags:
+//
+//	  -diff
+//		instead of applying each fix, print the patch as a unified diff
+//
+// The -fixtool=prog flag selects a different analysis tool with
+// alternative or additional fixes; see the documentation for go vet's
+// -vettool flag for details.
 //
-// For more about fix, see 'go doc cmd/fix'.
 // For more about specifying packages, see 'go help packages'.
 //
-// To run fix with other options, run 'go tool fix'.
+// For a list of fixers and their flags, see 'go tool fix help'.
+//
+// For details of a specific fixer such as 'hostport',
+// see 'go tool fix help hostport'.
+//
+// The build flags supported by go fix are those that control package resolution
+// and execution, such as -C, -n, -x, -v, -tags, and -toolexec.
+// For more about these flags, see 'go help build'.
 //
 // See also: go fmt, go vet.
 //
@@ -2014,20 +2026,34 @@
 //
 //	go vet [build flags] [-vettool prog] [vet flags] [packages]
 //
-// Vet runs the Go vet command on the packages named by the import paths.
+// Vet runs the Go vet tool (cmd/vet) on the named packages
+// and reports diagnostics.
 //
-// For more about vet and its flags, see 'go doc cmd/vet'.
-// For more about specifying packages, see 'go help packages'.
-// For a list of checkers and their flags, see 'go tool vet help'.
-// For details of a specific checker such as 'printf', see 'go tool vet help printf'.
+// It supports these flags:
+//
+//	  -c int
+//		display offending line with this many lines of context (default -1)
+//	  -json
+//		emit JSON output
+//	  -fix
+//		instead of printing each diagnostic, apply its first fix (if any)
+//	  -diff
+//		instead of applying each fix, print the patch as a unified diff
 //
-// The -vettool=prog flag selects a different analysis tool with alternative
-// or additional checks.
-// For example, the 'shadow' analyzer can be built and run using these commands:
+// The -vettool=prog flag selects a different analysis tool with
+// alternative or additional checks. For example, the 'shadow' analyzer
+// can be built and run using these commands:
 //
 //	go install golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow@latest
 //	go vet -vettool=$(which shadow)
 //
+// Alternative vet tools should be built atop golang.org/x/tools/go/analysis/unitchecker,
+// which handles the interaction with go vet.
+//
+// For more about specifying packages, see 'go help packages'.
+// For a list of checkers and their flags, see 'go tool vet help'.
+// For details of a specific checker such as 'printf', see 'go tool vet help printf'.
+//
 // The build flags supported by go vet are those that control package resolution
 // and execution, such as -C, -n, -x, -v, -tags, and -toolexec.
 // For more about these flags, see 'go help build'.
diff --git a/src/cmd/go/internal/fix/fix.go b/src/cmd/go/internal/fix/fix.go
deleted file mode 100644
index 8947da05c3ee63..00000000000000
--- a/src/cmd/go/internal/fix/fix.go
+++ /dev/null
@@ -1,86 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package fix implements the “go fix” command.
-package fix
-
-import (
-	"cmd/go/internal/base"
-	"cmd/go/internal/cfg"
-	"cmd/go/internal/load"
-	"cmd/go/internal/modload"
-	"cmd/go/internal/str"
-	"cmd/go/internal/work"
-	"context"
-	"fmt"
-	"go/build"
-	"os"
-	"path/filepath"
-)
-
-var CmdFix = &base.Command{
-	UsageLine: "go fix [-fix list] [packages]",
-	Short:     "update packages to use new APIs",
-	Long: `
-Fix runs the Go fix command on the packages named by the import paths.
-
-The -fix flag sets a comma-separated list of fixes to run.
-The default is all known fixes.
-(Its value is passed to 'go tool fix -r'.)
-
-For more about fix, see 'go doc cmd/fix'.
-For more about specifying packages, see 'go help packages'.
-
-To run fix with other options, run 'go tool fix'.
-
-See also: go fmt, go vet.
-	`,
-}
-
-var fixes = CmdFix.Flag.String("fix", "", "comma-separated list of fixes to apply")
-
-func init() {
-	work.AddBuildFlags(CmdFix, work.OmitBuildOnlyFlags)
-	CmdFix.Run = runFix // fix cycle
-}
-
-func runFix(ctx context.Context, cmd *base.Command, args []string) {
-	pkgs := load.PackagesAndErrors(ctx, load.PackageOpts{}, args)
-	w := 0
-	for _, pkg := range pkgs {
-		if pkg.Error != nil {
-			base.Errorf("%v", pkg.Error)
-			continue
-		}
-		pkgs[w] = pkg
-		w++
-	}
-	pkgs = pkgs[:w]
-
-	printed := false
-	for _, pkg := range pkgs {
-		if modload.Enabled() && pkg.Module != nil && !pkg.Module.Main {
-			if !printed {
-				fmt.Fprintf(os.Stderr, "go: not fixing packages in dependency modules\n")
-				printed = true
-			}
-			continue
-		}
-		// Use pkg.gofiles instead of pkg.Dir so that
-		// the command only applies to this package,
-		// not to packages in subdirectories.
-		files := base.RelPaths(pkg.InternalAllGoFiles())
-		goVersion := ""
-		if pkg.Module != nil {
-			goVersion = "go" + pkg.Module.GoVersion
-		} else if pkg.Standard {
-			goVersion = build.Default.ReleaseTags[len(build.Default.ReleaseTags)-1]
-		}
-		var fixArg []string
-		if *fixes != "" {
-			fixArg = []string{"-r=" + *fixes}
-		}
-		base.Run(str.StringList(cfg.BuildToolexec, filepath.Join(cfg.GOROOTbin, "go"), "tool", "fix", "-go="+goVersion, fixArg, files))
-	}
-}
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 15ffc618c65dab..e667bd64f7997f 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -707,6 +707,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 	work.BuildInit()
 	work.VetFlags = testVet.flags
 	work.VetExplicit = testVet.explicit
+	work.VetTool = base.Tool("vet")
 
 	pkgOpts := load.PackageOpts{ModResolveTests: true}
 	pkgs = load.PackagesAndErrors(ctx, pkgOpts, pkgArgs)
diff --git a/src/cmd/go/internal/vet/vet.go b/src/cmd/go/internal/vet/vet.go
index 3514be80feb8cc..a2625b21188cf4 100644
--- a/src/cmd/go/internal/vet/vet.go
+++ b/src/cmd/go/internal/vet/vet.go
@@ -2,13 +2,20 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package vet implements the “go vet” command.
+// Package vet implements the “go vet” and “go fix” commands.
 package vet
 
 import (
 	"context"
+	"encoding/json"
+	"errors"
 	"fmt"
-	"path/filepath"
+	"io"
+	"os"
+	"slices"
+	"strconv"
+	"strings"
+	"sync"
 
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
@@ -18,30 +25,39 @@ import (
 	"cmd/go/internal/work"
 )
 
-// Break init loop.
-func init() {
-	CmdVet.Run = runVet
-}
-
 var CmdVet = &base.Command{
 	CustomFlags: true,
 	UsageLine:   "go vet [build flags] [-vettool prog] [vet flags] [packages]",
 	Short:       "report likely mistakes in packages",
 	Long: `
-Vet runs the Go vet command on the packages named by the import paths.
+Vet runs the Go vet tool (cmd/vet) on the named packages
+and reports diagnostics.
 
-For more about vet and its flags, see 'go doc cmd/vet'.
-For more about specifying packages, see 'go help packages'.
-For a list of checkers and their flags, see 'go tool vet help'.
-For details of a specific checker such as 'printf', see 'go tool vet help printf'.
+It supports these flags:
 
-The -vettool=prog flag selects a different analysis tool with alternative
-or additional checks.
-For example, the 'shadow' analyzer can be built and run using these commands:
+  -c int
+	display offending line with this many lines of context (default -1)
+  -json
+	emit JSON output
+  -fix
+	instead of printing each diagnostic, apply its first fix (if any)
+  -diff
+	instead of applying each fix, print the patch as a unified diff
+
+The -vettool=prog flag selects a different analysis tool with
+alternative or additional checks. For example, the 'shadow' analyzer
+can be built and run using these commands:
 
   go install golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow@latest
   go vet -vettool=$(which shadow)
 
+Alternative vet tools should be built atop golang.org/x/tools/go/analysis/unitchecker,
+which handles the interaction with go vet.
+
+For more about specifying packages, see 'go help packages'.
+For a list of checkers and their flags, see 'go tool vet help'.
+For details of a specific checker such as 'printf', see 'go tool vet help printf'.
+
 The build flags supported by go vet are those that control package resolution
 and execution, such as -C, -n, -x, -v, -tags, and -toolexec.
 For more about these flags, see 'go help build'.
@@ -50,9 +66,64 @@ See also: go fmt, go fix.
 	`,
 }
 
-func runVet(ctx context.Context, cmd *base.Command, args []string) {
-	vetFlags, pkgArgs := vetFlags(args)
-	modload.InitWorkfile() // The vet command does custom flag processing; initialize workspaces after that.
+var CmdFix = &base.Command{
+	CustomFlags: true,
+	UsageLine:   "go fix [build flags] [-fixtool prog] [fix flags] [packages]",
+	Short:       "apply fixes suggested by static checkers",
+	Long: `
+Fix runs the Go fix tool (cmd/vet) on the named packages
+and applies suggested fixes.
+
+It supports these flags:
+
+  -diff
+	instead of applying each fix, print the patch as a unified diff
+
+The -fixtool=prog flag selects a different analysis tool with
+alternative or additional fixes; see the documentation for go vet's
+-vettool flag for details.
+
+For more about specifying packages, see 'go help packages'.
+
+For a list of fixers and their flags, see 'go tool fix help'.
+
+For details of a specific fixer such as 'hostport',
+see 'go tool fix help hostport'.
+
+The build flags supported by go fix are those that control package resolution
+and execution, such as -C, -n, -x, -v, -tags, and -toolexec.
+For more about these flags, see 'go help build'.
+
+See also: go fmt, go vet.
+	`,
+}
+
+func init() {
+	// avoid initialization cycle
+	CmdVet.Run = run
+	CmdFix.Run = run
+
+	addFlags(CmdVet)
+	addFlags(CmdFix)
+}
+
+var (
+	// "go vet -fix" causes fixes to be applied.
+	vetFixFlag = CmdVet.Flag.Bool("fix", false, "apply the first fix (if any) for each diagnostic")
+
+	// The "go fix -fix=name,..." flag is an obsolete flag formerly
+	// used to pass a list of names to the old "cmd/fix -r".
+	fixFixFlag = CmdFix.Flag.String("fix", "", "obsolete; no effect")
+)
+
+// run implements both "go vet" and "go fix".
+func run(ctx context.Context, cmd *base.Command, args []string) {
+	// Compute flags for the vet/fix tool (e.g. cmd/{vet,fix}).
+	toolFlags, pkgArgs := toolFlags(cmd, args)
+
+	// The vet/fix commands do custom flag processing;
+	// initialize workspaces after that.
+	modload.InitWorkfile()
 
 	if cfg.DebugTrace != "" {
 		var close func() error
@@ -72,23 +143,84 @@ func runVet(ctx context.Context, cmd *base.Command, args []string) {
 	defer span.Done()
 
 	work.BuildInit()
-	work.VetFlags = vetFlags
-	if len(vetFlags) > 0 {
-		work.VetExplicit = true
+
+	// Flag theory:
+	//
+	// All flags supported by unitchecker are accepted by go {vet,fix}.
+	// Some arise from each analyzer in the tool (both to enable it
+	// and to configure it), whereas others [-V -c -diff -fix -flags -json]
+	// are core to unitchecker itself.
+	//
+	// Most are passed through to toolFlags, but not all:
+	// * -V and -flags are used by the handshake in the [toolFlags] function;
+	// * these old flags have no effect: [-all -source -tags -v]; and
+	// * the [-c -fix -diff -json] flags are handled specially
+	//   as described below:
+	//
+	// command args                 tool args
+	// go vet               =>      cmd/vet -json           Parse stdout, print diagnostics to stderr.
+	// go vet -json         =>      cmd/vet -json           Pass stdout through.
+	// go vet -fix [-diff]  =>      cmd/vet -fix [-diff]    Pass stdout through.
+	// go fix [-diff]       =>      cmd/fix -fix [-diff]    Pass stdout through.
+	// go fix -json         =>      cmd/fix -json           Pass stdout through.
+	//
+	// Notes:
+	// * -diff requires "go vet -fix" or "go fix", and no -json.
+	// * -json output is the same in "vet" and "fix" modes,
+	//   and describes both diagnostics and fixes (but does not apply them).
+	// * -c=n is supported by the unitchecker, but we reimplement it
+	//   here (see printDiagnostics), and do not pass the flag through.
+
+	work.VetExplicit = len(toolFlags) > 0
+
+	if cmd.Name() == "fix" || *vetFixFlag {
+		// fix mode: 'go fix' or 'go vet -fix'
+		if jsonFlag {
+			if diffFlag {
+				base.Fatalf("-json and -diff cannot be used together")
+			}
+		} else {
+			toolFlags = append(toolFlags, "-fix")
+			if diffFlag {
+				toolFlags = append(toolFlags, "-diff")
+			}
+		}
+		if contextFlag != -1 {
+			base.Fatalf("-c flag cannot be used when applying fixes")
+		}
+	} else {
+		// vet mode: 'go vet' without -fix
+		if !jsonFlag {
+			// Post-process the JSON diagnostics on stdout and format
+			// it as "file:line: message" diagnostics on stderr.
+			// (JSON reliably frames diagnostics, fixes, and errors so
+			// that we don't have to parse stderr or interpret non-zero
+			// exit codes, and interacts better with the action cache.)
+			toolFlags = append(toolFlags, "-json")
+			work.VetHandleStdout = printJSONDiagnostics
+		}
+		if diffFlag {
+			base.Fatalf("go vet -diff flag requires -fix")
+		}
 	}
-	if vetTool != "" {
-		var err error
-		work.VetTool, err = filepath.Abs(vetTool)
-		if err != nil {
-			base.Fatalf("%v", err)
+
+	// Implement legacy "go fix -fix=name,..." flag.
+	if *fixFixFlag != "" {
+		fmt.Fprintf(os.Stderr, "go %s: the -fix=%s flag is obsolete and has no effect", cmd.Name(), *fixFixFlag)
+
+		// The buildtag fixer is now implemented by cmd/fix.
+		if slices.Contains(strings.Split(*fixFixFlag, ","), "buildtag") {
+			fmt.Fprintf(os.Stderr, "go %s: to enable the buildtag check, use -buildtag", cmd.Name())
 		}
 	}
 
+	work.VetFlags = toolFlags
+
 	pkgOpts := load.PackageOpts{ModResolveTests: true}
 	pkgs := load.PackagesAndErrors(ctx, pkgOpts, pkgArgs)
 	load.CheckPackageErrors(pkgs)
 	if len(pkgs) == 0 {
-		base.Fatalf("no packages to vet")
+		base.Fatalf("no packages to %s", cmd.Name())
 	}
 
 	b := work.NewBuilder("")
@@ -98,7 +230,23 @@ func runVet(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	}()
 
-	root := &work.Action{Mode: "go vet"}
+	// To avoid file corruption from duplicate application of
+	// fixes (in fix mode), and duplicate reporting of diagnostics
+	// (in vet mode), we must run the tool only once for each
+	// source file. We achieve that by running on ptest (below)
+	// instead of p.
+	//
+	// As a side benefit, this also allows analyzers to make
+	// "closed world" assumptions and report diagnostics (such as
+	// "this symbol is unused") that might be false if computed
+	// from just the primary package p, falsified by the
+	// additional declarations in test files.
+	//
+	// We needn't worry about intermediate test variants, as they
+	// will only be executed in VetxOnly mode, for facts but not
+	// diagnostics.
+
+	root := &work.Action{Mode: "go " + cmd.Name()}
 	for _, p := range pkgs {
 		_, ptest, pxtest, perr := load.TestPackagesFor(ctx, pkgOpts, p, nil)
 		if perr != nil {
@@ -106,10 +254,11 @@ func runVet(ctx context.Context, cmd *base.Command, args []string) {
 			continue
 		}
 		if len(ptest.GoFiles) == 0 && len(ptest.CgoFiles) == 0 && pxtest == nil {
-			base.Errorf("go: can't vet %s: no Go files in %s", p.ImportPath, p.Dir)
+			base.Errorf("go: can't %s %s: no Go files in %s", cmd.Name(), p.ImportPath, p.Dir)
 			continue
 		}
 		if len(ptest.GoFiles) > 0 || len(ptest.CgoFiles) > 0 {
+			// The test package includes all the files of primary package.
 			root.Deps = append(root.Deps, b.VetAction(work.ModeBuild, work.ModeBuild, ptest))
 		}
 		if pxtest != nil {
@@ -118,3 +267,167 @@ func runVet(ctx context.Context, cmd *base.Command, args []string) {
 	}
 	b.Do(ctx, root)
 }
+
+// printJSONDiagnostics parses JSON (from the tool's stdout) and
+// prints it (to stderr) in "file:line: message" form.
+// It also ensures that we exit nonzero if there were diagnostics.
+func printJSONDiagnostics(r io.Reader) error {
+	stdout, err := io.ReadAll(r)
+	if err != nil {
+		return err
+	}
+	if len(stdout) > 0 {
+		// unitchecker emits a JSON map of the form:
+		// output maps Package ID -> Analyzer.Name -> (error | []Diagnostic);
+		var tree jsonTree
+		if err := json.Unmarshal([]byte(stdout), &tree); err != nil {
+			return fmt.Errorf("parsing JSON: %v", err)
+		}
+		for _, units := range tree {
+			for analyzer, msg := range units {
+				if msg[0] == '[' {
+					// []Diagnostic
+					var diags []jsonDiagnostic
+					if err := json.Unmarshal([]byte(msg), &diags); err != nil {
+						return fmt.Errorf("parsing JSON diagnostics: %v", err)
+					}
+					for _, diag := range diags {
+						base.SetExitStatus(1)
+						printJSONDiagnostic(analyzer, diag)
+					}
+				} else {
+					// error
+					var e jsonError
+					if err := json.Unmarshal([]byte(msg), &e); err != nil {
+						return fmt.Errorf("parsing JSON error: %v", err)
+					}
+
+					base.SetExitStatus(1)
+					return errors.New(e.Err)
+				}
+			}
+		}
+	}
+	return nil
+}
+
+var stderrMu sync.Mutex // serializes concurrent writes to stdout
+
+func printJSONDiagnostic(analyzer string, diag jsonDiagnostic) {
+	stderrMu.Lock()
+	defer stderrMu.Unlock()
+
+	type posn struct {
+		file      string
+		line, col int
+	}
+	parsePosn := func(s string) (_ posn, _ bool) {
+		colon2 := strings.LastIndexByte(s, ':')
+		if colon2 < 0 {
+			return
+		}
+		colon1 := strings.LastIndexByte(s[:colon2], ':')
+		if colon1 < 0 {
+			return
+		}
+		line, err := strconv.Atoi(s[colon1+len(":") : colon2])
+		if err != nil {
+			return
+		}
+		col, err := strconv.Atoi(s[colon2+len(":"):])
+		if err != nil {
+			return
+		}
+		return posn{s[:colon1], line, col}, true
+	}
+
+	print := func(start, end, message string) {
+		if posn, ok := parsePosn(start); ok {
+			// The (*work.Shell).reportCmd method relativizes the
+			// prefix of each line of the subprocess's stdout;
+			// but filenames in JSON aren't at the start of the line,
+			// so we need to apply ShortPath here too.
+			fmt.Fprintf(os.Stderr, "%s:%d:%d: %v\n", base.ShortPath(posn.file), posn.line, posn.col, message)
+		} else {
+			fmt.Fprintf(os.Stderr, "%s: %v\n", start, message)
+		}
+
+		// -c=n: show offending line plus N lines of context.
+		// (Duplicates logic in unitchecker; see analysisflags.PrintPlain.)
+		if contextFlag >= 0 {
+			if end == "" {
+				end = start
+			}
+			var (
+				startPosn, ok1 = parsePosn(start)
+				endPosn, ok2   = parsePosn(end)
+			)
+			if ok1 && ok2 {
+				// TODO(adonovan): respect overlays (like unitchecker does).
+				data, _ := os.ReadFile(startPosn.file)
+				lines := strings.Split(string(data), "\n")
+				for i := startPosn.line - contextFlag; i <= endPosn.line+contextFlag; i++ {
+					if 1 <= i && i <= len(lines) {
+						fmt.Fprintf(os.Stderr, "%d\t%s\n", i, lines[i-1])
+					}
+				}
+			}
+		}
+	}
+
+	// TODO(adonovan): append  " [analyzer]" to message. But we must first relax
+	// x/tools/go/analysis/internal/versiontest.TestVettool and revendor; sigh.
+	_ = analyzer
+	print(diag.Posn, diag.End, diag.Message)
+	for _, rel := range diag.Related {
+		print(rel.Posn, rel.End, "\t"+rel.Message)
+	}
+}
+
+// -- JSON schema --
+
+// (populated by golang.org/x/tools/go/analysis/internal/analysisflags/flags.go)
+
+// A jsonTree is a mapping from package ID to analysis name to result.
+// Each result is either a jsonError or a list of jsonDiagnostic.
+type jsonTree map[string]map[string]json.RawMessage
+
+type jsonError struct {
+	Err string `json:"error"`
+}
+
+// A TextEdit describes the replacement of a portion of a file.
+// Start and End are zero-based half-open indices into the original byte
+// sequence of the file, and New is the new text.
+type jsonTextEdit struct {
+	Filename string `json:"filename"`
+	Start    int    `json:"start"`
+	End      int    `json:"end"`
+	New      string `json:"new"`
+}
+
+// A jsonSuggestedFix describes an edit that should be applied as a whole or not
+// at all. It might contain multiple TextEdits/text_edits if the SuggestedFix
+// consists of multiple non-contiguous edits.
+type jsonSuggestedFix struct {
+	Message string         `json:"message"`
+	Edits   []jsonTextEdit `json:"edits"`
+}
+
+// A jsonDiagnostic describes the json schema of an analysis.Diagnostic.
+type jsonDiagnostic struct {
+	Category       string                   `json:"category,omitempty"`
+	Posn           string                   `json:"posn"` // e.g. "file.go:line:column"
+	End            string                   `json:"end"`
+	Message        string                   `json:"message"`
+	SuggestedFixes []jsonSuggestedFix       `json:"suggested_fixes,omitempty"`
+	Related        []jsonRelatedInformation `json:"related,omitempty"`
+}
+
+// A jsonRelated describes a secondary position and message related to
+// a primary diagnostic.
+type jsonRelatedInformation struct {
+	Posn    string `json:"posn"` // e.g. "file.go:line:column"
+	End     string `json:"end"`
+	Message string `json:"message"`
+}
diff --git a/src/cmd/go/internal/vet/vetflag.go b/src/cmd/go/internal/vet/vetflag.go
index d0bdb58a504ae7..7ebd8c9bfd19eb 100644
--- a/src/cmd/go/internal/vet/vetflag.go
+++ b/src/cmd/go/internal/vet/vetflag.go
@@ -21,70 +21,83 @@ import (
 	"cmd/go/internal/work"
 )
 
-// go vet flag processing
-//
-// We query the flags of the tool specified by -vettool and accept any
-// of those flags plus any flag valid for 'go build'. The tool must
-// support -flags, which prints a description of its flags in JSON to
-// stdout.
-
-// vetTool specifies the vet command to run.
-// Any tool that supports the (still unpublished) vet
-// command-line protocol may be supplied; see
-// golang.org/x/tools/go/analysis/unitchecker for one
-// implementation. It is also used by tests.
-//
-// The default behavior (vetTool=="") runs 'go tool vet'.
-var vetTool string // -vettool
-
-func init() {
-	// For now, we omit the -json flag for vet because we could plausibly
-	// support -json specific to the vet command in the future (perhaps using
-	// the same format as build -json).
-	work.AddBuildFlags(CmdVet, work.OmitJSONFlag)
-	CmdVet.Flag.StringVar(&vetTool, "vettool", "", "")
+// go vet/fix flag processing
+var (
+	// We query the flags of the tool specified by -{vet,fix}tool
+	// and accept any of those flags plus any flag valid for 'go
+	// build'. The tool must support -flags, which prints a
+	// description of its flags in JSON to stdout.
+
+	// toolFlag specifies the vet/fix command to run.
+	// Any toolFlag that supports the (unpublished) vet
+	// command-line protocol may be supplied; see
+	// golang.org/x/tools/go/analysis/unitchecker for the
+	// sole implementation. It is also used by tests.
+	//
+	// The default behavior ("") runs 'go tool {vet,fix}'.
+	//
+	// Do not access this flag directly; use [parseToolFlag].
+	toolFlag    string // -{vet,fix}tool
+	diffFlag    bool   // -diff
+	jsonFlag    bool   // -json
+	contextFlag = -1   // -c=n
+)
+
+func addFlags(cmd *base.Command) {
+	// We run the compiler for export data.
+	// Suppress the build -json flag; we define our own.
+	work.AddBuildFlags(cmd, work.OmitJSONFlag)
+
+	cmd.Flag.StringVar(&toolFlag, cmd.Name()+"tool", "", "") // -vettool or -fixtool
+	cmd.Flag.BoolVar(&diffFlag, "diff", false, "print diff instead of applying it")
+	cmd.Flag.BoolVar(&jsonFlag, "json", false, "print diagnostics and fixes as JSON")
+	cmd.Flag.IntVar(&contextFlag, "c", -1, "display offending line with this many lines of context")
 }
 
-func parseVettoolFlag(args []string) {
-	// Extract -vettool by ad hoc flag processing:
+// parseToolFlag scans args for -{vet,fix}tool and returns the effective tool filename.
+func parseToolFlag(cmd *base.Command, args []string) string {
+	toolFlagName := cmd.Name() + "tool" // vettool or fixtool
+
+	// Extract -{vet,fix}tool by ad hoc flag processing:
 	// its value is needed even before we can declare
 	// the flags available during main flag processing.
 	for i, arg := range args {
-		if arg == "-vettool" || arg == "--vettool" {
+		if arg == "-"+toolFlagName || arg == "--"+toolFlagName {
 			if i+1 >= len(args) {
 				log.Fatalf("%s requires a filename", arg)
 			}
-			vetTool = args[i+1]
-			return
-		} else if strings.HasPrefix(arg, "-vettool=") ||
-			strings.HasPrefix(arg, "--vettool=") {
-			vetTool = arg[strings.IndexByte(arg, '=')+1:]
-			return
+			toolFlag = args[i+1]
+			break
+		} else if strings.HasPrefix(arg, "-"+toolFlagName+"=") ||
+			strings.HasPrefix(arg, "--"+toolFlagName+"=") {
+			toolFlag = arg[strings.IndexByte(arg, '=')+1:]
+			break
 		}
 	}
-}
 
-// vetFlags processes the command line, splitting it at the first non-flag
-// into the list of flags and list of packages.
-func vetFlags(args []string) (passToVet, packageNames []string) {
-	parseVettoolFlag(args)
-
-	// Query the vet command for its flags.
-	var tool string
-	if vetTool == "" {
-		tool = base.Tool("vet")
-	} else {
-		var err error
-		tool, err = filepath.Abs(vetTool)
+	if toolFlag != "" {
+		tool, err := filepath.Abs(toolFlag)
 		if err != nil {
 			log.Fatal(err)
 		}
+		return tool
 	}
+
+	return base.Tool(cmd.Name()) // default to 'go tool vet|fix'
+}
+
+// toolFlags processes the command line, splitting it at the first non-flag
+// into the list of flags and list of packages.
+func toolFlags(cmd *base.Command, args []string) (passToTool, packageNames []string) {
+	tool := parseToolFlag(cmd, args)
+	work.VetTool = tool
+
+	// Query the tool for its flags.
 	out := new(bytes.Buffer)
-	vetcmd := exec.Command(tool, "-flags")
-	vetcmd.Stdout = out
-	if err := vetcmd.Run(); err != nil {
-		fmt.Fprintf(os.Stderr, "go: can't execute %s -flags: %v\n", tool, err)
+	toolcmd := exec.Command(tool, "-flags")
+	toolcmd.Stdout = out
+	if err := toolcmd.Run(); err != nil {
+		fmt.Fprintf(os.Stderr, "go: %s -flags failed: %v\n", tool, err)
 		base.SetExitStatus(2)
 		base.Exit()
 	}
@@ -99,15 +112,20 @@ func vetFlags(args []string) (passToVet, packageNames []string) {
 		base.Exit()
 	}
 
-	// Add vet's flags to CmdVet.Flag.
+	// Add tool's flags to cmd.Flag.
 	//
-	// Some flags, in particular -tags and -v, are known to vet but
+	// Some flags, in particular -tags and -v, are known to the tool but
 	// also defined as build flags. This works fine, so we omit duplicates here.
-	// However some, like -x, are known to the build but not to vet.
-	isVetFlag := make(map[string]bool, len(analysisFlags))
-	cf := CmdVet.Flag
+	// However some, like -x, are known to the build but not to the tool.
+	isToolFlag := make(map[string]bool, len(analysisFlags))
+	cf := cmd.Flag
 	for _, f := range analysisFlags {
-		isVetFlag[f.Name] = true
+		// We reimplement the unitchecker's -c=n flag.
+		// Don't allow it to be passed through.
+		if f.Name == "c" {
+			continue
+		}
+		isToolFlag[f.Name] = true
 		if cf.Lookup(f.Name) == nil {
 			if f.Bool {
 				cf.Bool(f.Name, false, "")
@@ -117,22 +135,22 @@ func vetFlags(args []string) (passToVet, packageNames []string) {
 		}
 	}
 
-	// Record the set of vet tool flags set by GOFLAGS. We want to pass them to
-	// the vet tool, but only if they aren't overridden by an explicit argument.
-	base.SetFromGOFLAGS(&CmdVet.Flag)
+	// Record the set of tool flags set by GOFLAGS. We want to pass them to
+	// the tool, but only if they aren't overridden by an explicit argument.
+	base.SetFromGOFLAGS(&cmd.Flag)
 	addFromGOFLAGS := map[string]bool{}
-	CmdVet.Flag.Visit(func(f *flag.Flag) {
-		if isVetFlag[f.Name] {
+	cmd.Flag.Visit(func(f *flag.Flag) {
+		if isToolFlag[f.Name] {
 			addFromGOFLAGS[f.Name] = true
 		}
 	})
 
 	explicitFlags := make([]string, 0, len(args))
 	for len(args) > 0 {
-		f, remainingArgs, err := cmdflag.ParseOne(&CmdVet.Flag, args)
+		f, remainingArgs, err := cmdflag.ParseOne(&cmd.Flag, args)
 
 		if errors.Is(err, flag.ErrHelp) {
-			exitWithUsage()
+			exitWithUsage(cmd)
 		}
 
 		if errors.Is(err, cmdflag.ErrFlagTerminator) {
@@ -151,12 +169,12 @@ func vetFlags(args []string) (passToVet, packageNames []string) {
 
 		if err != nil {
 			fmt.Fprintln(os.Stderr, err)
-			exitWithUsage()
+			exitWithUsage(cmd)
 		}
 
-		if isVetFlag[f.Name] {
+		if isToolFlag[f.Name] {
 			// Forward the raw arguments rather than cleaned equivalents, just in
-			// case the vet tool parses them idiosyncratically.
+			// case the tool parses them idiosyncratically.
 			explicitFlags = append(explicitFlags, args[:len(args)-len(remainingArgs)]...)
 
 			// This flag has been overridden explicitly, so don't forward its implicit
@@ -168,26 +186,26 @@ func vetFlags(args []string) (passToVet, packageNames []string) {
 	}
 
 	// Prepend arguments from GOFLAGS before other arguments.
-	CmdVet.Flag.Visit(func(f *flag.Flag) {
+	cmd.Flag.Visit(func(f *flag.Flag) {
 		if addFromGOFLAGS[f.Name] {
-			passToVet = append(passToVet, fmt.Sprintf("-%s=%s", f.Name, f.Value))
+			passToTool = append(passToTool, fmt.Sprintf("-%s=%s", f.Name, f.Value))
 		}
 	})
-	passToVet = append(passToVet, explicitFlags...)
-	return passToVet, packageNames
+	passToTool = append(passToTool, explicitFlags...)
+	return passToTool, packageNames
 }
 
-func exitWithUsage() {
-	fmt.Fprintf(os.Stderr, "usage: %s\n", CmdVet.UsageLine)
-	fmt.Fprintf(os.Stderr, "Run 'go help %s' for details.\n", CmdVet.LongName())
+func exitWithUsage(cmd *base.Command) {
+	fmt.Fprintf(os.Stderr, "usage: %s\n", cmd.UsageLine)
+	fmt.Fprintf(os.Stderr, "Run 'go help %s' for details.\n", cmd.LongName())
 
 	// This part is additional to what (*Command).Usage does:
-	cmd := "go tool vet"
-	if vetTool != "" {
-		cmd = vetTool
+	tool := toolFlag
+	if tool == "" {
+		tool = "go tool " + cmd.Name()
 	}
-	fmt.Fprintf(os.Stderr, "Run '%s help' for a full list of flags and analyzers.\n", cmd)
-	fmt.Fprintf(os.Stderr, "Run '%s -help' for an overview.\n", cmd)
+	fmt.Fprintf(os.Stderr, "Run '%s help' for a full list of flags and analyzers.\n", tool)
+	fmt.Fprintf(os.Stderr, "Run '%s -help' for an overview.\n", tool)
 
 	base.SetExitStatus(2)
 	base.Exit()
diff --git a/src/cmd/go/internal/work/buildid.go b/src/cmd/go/internal/work/buildid.go
index 88c24b11acc172..584c1ac6f41d23 100644
--- a/src/cmd/go/internal/work/buildid.go
+++ b/src/cmd/go/internal/work/buildid.go
@@ -148,9 +148,10 @@ func (b *Builder) toolID(name string) string {
 		path := base.Tool(name)
 		desc := "go tool " + name
 
-		// Special case: undocumented -vettool overrides usual vet,
-		// for testing vet or supplying an alternative analysis tool.
-		if name == "vet" && VetTool != "" {
+		// Special case: -{vet,fix}tool overrides usual cmd/{vet,fix}
+		// for testing or supplying an alternative analysis tool.
+		// (We use only "vet" terminology in the action graph.)
+		if name == "vet" {
 			path = VetTool
 			desc = VetTool
 		}
diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index 72b9177c9dbbeb..fa6ddce24bed3c 100644
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -1265,7 +1265,8 @@ func buildVetConfig(a *Action, srcfiles []string) {
 	}
 }
 
-// VetTool is the path to an alternate vet tool binary.
+// VetTool is the path to the effective vet or fix tool binary.
+// The user may specify a non-default value using -{vet,fix}tool.
 // The caller is expected to set it (if needed) before executing any vet actions.
 var VetTool string
 
@@ -1273,7 +1274,13 @@ var VetTool string
 // The caller is expected to set them before executing any vet actions.
 var VetFlags []string
 
-// VetExplicit records whether the vet flags were set explicitly on the command line.
+// VetHandleStdout determines how the stdout output of each vet tool
+// invocation should be handled. The default behavior is to copy it to
+// the go command's stdout, atomically.
+var VetHandleStdout = copyToStdout
+
+// VetExplicit records whether the vet flags (which may include
+// -{vet,fix}tool) were set explicitly on the command line.
 var VetExplicit bool
 
 func (b *Builder) vet(ctx context.Context, a *Action) error {
@@ -1296,6 +1303,7 @@ func (b *Builder) vet(ctx context.Context, a *Action) error {
 
 	sh := b.Shell(a)
 
+	// We use "vet" terminology even when building action graphs for go fix.
 	vcfg.VetxOnly = a.VetxOnly
 	vcfg.VetxOutput = a.Objdir + "vet.out"
 	vcfg.Stdout = a.Objdir + "vet.stdout"
@@ -1322,7 +1330,7 @@ func (b *Builder) vet(ctx context.Context, a *Action) error {
 	// dependency tree turn on *more* analysis, as here.
 	// (The unsafeptr check does not write any facts for use by
 	// later vet runs, nor does unreachable.)
-	if a.Package.Goroot && !VetExplicit && VetTool == "" {
+	if a.Package.Goroot && !VetExplicit && VetTool == base.Tool("vet") {
 		// Turn off -unsafeptr checks.
 		// There's too much unsafe.Pointer code
 		// that vet doesn't like in low-level packages
@@ -1359,13 +1367,29 @@ func (b *Builder) vet(ctx context.Context, a *Action) error {
 			vcfg.PackageVetx[a1.Package.ImportPath] = a1.built
 		}
 	}
-	key := cache.ActionID(h.Sum())
+	vetxKey := cache.ActionID(h.Sum()) // for .vetx file
+
+	fmt.Fprintf(h, "stdout\n")
+	stdoutKey := cache.ActionID(h.Sum()) // for .stdout file
 
-	if vcfg.VetxOnly && !cfg.BuildA {
+	// Check the cache; -a forces a rebuild.
+	if !cfg.BuildA {
 		c := cache.Default()
-		if file, _, err := cache.GetFile(c, key); err == nil {
-			a.built = file
-			return nil
+		if vcfg.VetxOnly {
+			if file, _, err := cache.GetFile(c, vetxKey); err == nil {
+				a.built = file
+				return nil
+			}
+		} else {
+			// Copy cached vet.std files to stdout.
+			if file, _, err := cache.GetFile(c, stdoutKey); err == nil {
+				f, err := os.Open(file)
+				if err != nil {
+					return err
+				}
+				defer f.Close() // ignore error (can't fail)
+				return VetHandleStdout(f)
+			}
 		}
 	}
 
@@ -1387,31 +1411,46 @@ func (b *Builder) vet(ctx context.Context, a *Action) error {
 	p := a.Package
 	tool := VetTool
 	if tool == "" {
-		tool = base.Tool("vet")
+		panic("VetTool unset")
+	}
+
+	if err := sh.run(p.Dir, p.ImportPath, env, cfg.BuildToolexec, tool, vetFlags, a.Objdir+"vet.cfg"); err != nil {
+		return err
 	}
-	runErr := sh.run(p.Dir, p.ImportPath, env, cfg.BuildToolexec, tool, vetFlags, a.Objdir+"vet.cfg")
 
-	// If vet wrote export data, save it for input to future vets.
+	// Vet tool succeeded, possibly with facts and JSON stdout. Save both in cache.
+
+	// Save facts
 	if f, err := os.Open(vcfg.VetxOutput); err == nil {
+		defer f.Close() // ignore error
 		a.built = vcfg.VetxOutput
-		cache.Default().Put(key, f) // ignore error
-		f.Close()                   // ignore error
+		cache.Default().Put(vetxKey, f) // ignore error
 	}
 
-	// If vet wrote to stdout, copy it to go's stdout, atomically.
+	// Save stdout.
 	if f, err := os.Open(vcfg.Stdout); err == nil {
-		stdoutMu.Lock()
-		if _, err := io.Copy(os.Stdout, f); err != nil && runErr == nil {
-			runErr = fmt.Errorf("copying vet tool stdout: %w", err)
+		defer f.Close() // ignore error
+		if err := VetHandleStdout(f); err != nil {
+			return err
 		}
-		f.Close() // ignore error
-		stdoutMu.Unlock()
+		f.Seek(0, io.SeekStart)           // ignore error
+		cache.Default().Put(stdoutKey, f) // ignore error
 	}
 
-	return runErr
+	return nil
 }
 
-var stdoutMu sync.Mutex // serializes concurrent writes (e.g. JSON values) to stdout
+var stdoutMu sync.Mutex // serializes concurrent writes (of e.g. JSON values) to stdout
+
+// copyToStdout copies the stream to stdout while holding the lock.
+func copyToStdout(r io.Reader) error {
+	stdoutMu.Lock()
+	defer stdoutMu.Unlock()
+	if _, err := io.Copy(os.Stdout, r); err != nil {
+		return fmt.Errorf("copying vet tool stdout: %w", err)
+	}
+	return nil
+}
 
 // linkActionID computes the action ID for a link action.
 func (b *Builder) linkActionID(a *Action) cache.ActionID {
diff --git a/src/cmd/go/main.go b/src/cmd/go/main.go
index e81969ca4a3144..8cdfd9196e4cb1 100644
--- a/src/cmd/go/main.go
+++ b/src/cmd/go/main.go
@@ -24,7 +24,6 @@ import (
 	"cmd/go/internal/clean"
 	"cmd/go/internal/doc"
 	"cmd/go/internal/envcmd"
-	"cmd/go/internal/fix"
 	"cmd/go/internal/fmtcmd"
 	"cmd/go/internal/generate"
 	"cmd/go/internal/help"
@@ -55,7 +54,7 @@ func init() {
 		clean.CmdClean,
 		doc.CmdDoc,
 		envcmd.CmdEnv,
-		fix.CmdFix,
+		vet.CmdFix,
 		fmtcmd.CmdFmt,
 		generate.CmdGenerate,
 		modget.CmdGet,
diff --git a/src/cmd/go/testdata/script/chdir.txt b/src/cmd/go/testdata/script/chdir.txt
index a6feed6b45fce0..41def410d5fa37 100644
--- a/src/cmd/go/testdata/script/chdir.txt
+++ b/src/cmd/go/testdata/script/chdir.txt
@@ -27,6 +27,10 @@ stderr 'strings\.test'
 go vet -C ../strings -n
 stderr strings_test
 
+# go fix
+go fix -C ../strings -n
+stderr strings_test
+
 # -C must be first on command line (as of Go 1.21)
 ! go test -n -C ../strings
 stderr '^invalid value "../strings" for flag -C: -C flag must be first flag on command line$'
diff --git a/src/cmd/go/testdata/script/vet_asm.txt b/src/cmd/go/testdata/script/vet_asm.txt
index 8aa69ce1a3c999..c046773a06c0dc 100644
--- a/src/cmd/go/testdata/script/vet_asm.txt
+++ b/src/cmd/go/testdata/script/vet_asm.txt
@@ -1,12 +1,12 @@
-env GO111MODULE=off
-
 # Issue 27665. Verify that "go vet" analyzes non-Go files.
 
-[!GOARCH:amd64] skip
+env GO111MODULE=off
+env GOARCH=amd64
+
 ! go vet -asmdecl a
 stderr 'f: invalid MOVW of x'
 
-# -c flag shows context
+# -c=n flag shows n lines of context
 ! go vet -c=2 -asmdecl a
 stderr '...invalid MOVW...'
 stderr '1	.*TEXT'
diff --git a/src/cmd/go/testdata/script/vet_basic.txt b/src/cmd/go/testdata/script/vet_basic.txt
new file mode 100644
index 00000000000000..5ae66438ea3d81
--- /dev/null
+++ b/src/cmd/go/testdata/script/vet_basic.txt
@@ -0,0 +1,125 @@
+# Test basic features of "go vet"/"go fix" CLI.
+#
+# The example relies on two analyzers:
+# - hostport (which is included in both the fix and vet suites), and
+# - printf (which is only in the vet suite).
+# Each reports one diagnostic with a fix.
+
+# vet default flags print diagnostics to stderr. Diagnostic => nonzero exit.
+! go vet example.com/x
+stderr 'does not work with IPv6'
+stderr 'non-constant format string in call to fmt.Sprintf'
+
+# -hostport runs only one analyzer. Diagnostic => failure.
+! go vet -hostport example.com/x
+stderr 'does not work with IPv6'
+! stderr 'non-constant format string'
+
+# -timeformat runs only one analyzer. No diagnostics => success.
+go vet -timeformat example.com/x
+! stderr .
+
+# JSON output includes diagnostics and fixes. Always success.
+go vet -json example.com/x
+! stderr .
+stdout '"example.com/x": {'
+stdout '"hostport":'
+stdout '"message": "address format .* does not work with IPv6",'
+stdout '"suggested_fixes":'
+stdout '"message": "Replace fmt.Sprintf with net.JoinHostPort",'
+
+# vet -fix -diff displays a diff.
+go vet -fix -diff example.com/x
+stdout '\-var _ = fmt.Sprintf\(s\)'
+stdout '\+var _ = fmt.Sprintf\("%s", s\)'
+stdout '\-var _, _ = net.Dial\("tcp", fmt.Sprintf\("%s:%d", s, 80\)\)'
+stdout '\+var _, _ = net.Dial\("tcp", net.JoinHostPort\(s, "80"\)\)'
+
+# vet -fix quietly applies the vet suite fixes.
+cp x.go x.go.bak
+go vet -fix example.com/x
+grep 'fmt.Sprintf\("%s", s\)' x.go
+grep 'net.JoinHostPort' x.go
+! stderr .
+cp x.go.bak x.go
+
+! go vet -diff example.com/x
+stderr 'go vet -diff flag requires -fix'
+
+# go fix applies the fix suite fixes.
+go fix example.com/x
+grep 'net.JoinHostPort' x.go
+! grep 'fmt.Sprintf\("%s", s\)' x.go
+! stderr .
+cp x.go.bak x.go
+
+# Show diff of fixes from the fix suite.
+go fix -diff example.com/x
+! stdout '\-var _ = fmt.Sprintf\(s\)'
+stdout '\-var _, _ = net.Dial\("tcp", fmt.Sprintf\("%s:%d", s, 80\)\)'
+stdout '\+var _, _ = net.Dial\("tcp", net.JoinHostPort\(s, "80"\)\)'
+
+# Show fix-suite fixes in JSON form.
+go fix -json example.com/x
+! stderr .
+stdout '"example.com/x": {'
+stdout '"hostport":'
+stdout '"message": "address format .* does not work with IPv6",'
+stdout '"suggested_fixes":'
+stdout '"message": "Replace fmt.Sprintf with net.JoinHostPort",'
+! stdout '"printf":'
+! stdout '"message": "non-constant format string.*",'
+! stdout '"message": "Insert.*%s.*format.string",'
+
+# Show vet-suite fixes in JSON form.
+go vet -fix -json example.com/x
+! stderr .
+stdout '"example.com/x": {'
+stdout '"hostport":'
+stdout '"message": "address format .* does not work with IPv6",'
+stdout '"suggested_fixes":'
+stdout '"message": "Replace fmt.Sprintf with net.JoinHostPort",'
+stdout '"printf":'
+stdout '"message": "non-constant format string.*",'
+stdout '"suggested_fixes":'
+stdout '"message": "Insert.*%s.*format.string",'
+
+# Reject -diff + -json.
+! go fix -diff -json example.com/x
+stderr '-json and -diff cannot be used together'
+
+# Legacy way of selecting fixers is a no-op.
+go fix -fix=old1,old2 example.com/x
+stderr 'go fix: the -fix=old1,old2 flag is obsolete and has no effect'
+
+# -c=n flag shows n lines of context.
+! go vet -c=2 -printf example.com/x
+stderr 'x.go:12:21: non-constant format string in call to fmt.Sprintf'
+! stderr '9	'
+stderr '10	'
+stderr '11	// This call...'
+stderr '12	var _ = fmt.Sprintf\(s\)'
+stderr '13	'
+stderr '14	'
+! stderr '15	'
+
+-- go.mod --
+module example.com/x
+go 1.25
+
+-- x.go --
+package x
+
+
+import (
+	"fmt"
+	"net"
+)
+
+var s string
+
+// This call yields a "non-constant format string" diagnostic, with a fix (go vet only).
+var _ = fmt.Sprintf(s)
+
+// This call yields a hostport diagnostic, with a fix (go vet and go fix).
+var _, _ = net.Dial("tcp", fmt.Sprintf("%s:%d", s, 80))
diff --git a/src/cmd/go/testdata/script/vet_cache.txt b/src/cmd/go/testdata/script/vet_cache.txt
new file mode 100644
index 00000000000000..c84844000a43d0
--- /dev/null
+++ b/src/cmd/go/testdata/script/vet_cache.txt
@@ -0,0 +1,24 @@
+# Test that go vet's caching of vet tool actions replays
+# the recorded stderr output even after a cache hit.
+
+# Set up fresh GOCACHE.
+env GOCACHE=$WORK/gocache
+
+# First time is a cache miss.
+! go vet example.com/a
+stderr 'fmt.Sprint call has possible Printf formatting directive'
+
+# Second time is assumed to be a cache hit for the stdout JSON,
+# but we don't bother to assert it. Same diagnostics again.
+! go vet example.com/a
+stderr 'fmt.Sprint call has possible Printf formatting directive'
+
+-- go.mod --
+module example.com
+
+-- a/a.go --
+package a
+
+import "fmt"
+
+var _ = fmt.Sprint("%s") // oops!
diff --git a/src/cmd/vet/doc.go b/src/cmd/vet/doc.go
index 8e72c252ed9984..ca208845615c8b 100644
--- a/src/cmd/vet/doc.go
+++ b/src/cmd/vet/doc.go
@@ -40,6 +40,7 @@ To list the available checks, run "go tool vet help":
 	directive        check Go toolchain directives such as //go:debug
 	errorsas         report passing non-pointer or non-error values to errors.As
 	framepointer     report assembly that clobbers the frame pointer before saving it
+	hostport         check format of addresses passed to net.Dial
 	httpresponse     check for mistakes using HTTP responses
 	ifaceassert      detect impossible interface-to-interface type assertions
 	loopclosure      check references to loop variables from within nested functions
@@ -50,6 +51,7 @@ To list the available checks, run "go tool vet help":
 	sigchanyzer      check for unbuffered channel of os.Signal
 	slog             check for invalid structured logging calls
 	stdmethods       check signature of methods of well-known interfaces
+	stdversion       report uses of too-new standard library symbols
 	stringintconv    check for string(int) conversions
 	structtag        check that struct field tags conform to reflect.StructTag.Get
 	testinggoroutine report calls to (*testing.T).Fatal from goroutines started by a test
diff --git a/src/cmd/vet/main.go b/src/cmd/vet/main.go
index 49f4e2f3425694..e7164a46b0a323 100644
--- a/src/cmd/vet/main.go
+++ b/src/cmd/vet/main.go
@@ -7,10 +7,8 @@ package main
 import (
 	"cmd/internal/objabi"
 	"cmd/internal/telemetry/counter"
-	"flag"
-
-	"golang.org/x/tools/go/analysis/unitchecker"
 
+	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/appends"
 	"golang.org/x/tools/go/analysis/passes/asmdecl"
 	"golang.org/x/tools/go/analysis/passes/assign"
@@ -46,52 +44,57 @@ import (
 	"golang.org/x/tools/go/analysis/passes/unsafeptr"
 	"golang.org/x/tools/go/analysis/passes/unusedresult"
 	"golang.org/x/tools/go/analysis/passes/waitgroup"
+	"golang.org/x/tools/go/analysis/unitchecker"
 )
 
 func main() {
+	// Keep consistent with cmd/fix/main.go!
 	counter.Open()
 	objabi.AddVersionFlag()
-
 	counter.Inc("vet/invocations")
-	unitchecker.Main(
-		appends.Analyzer,
-		asmdecl.Analyzer,
-		assign.Analyzer,
-		atomic.Analyzer,
-		bools.Analyzer,
-		buildtag.Analyzer,
-		cgocall.Analyzer,
-		composite.Analyzer,
-		copylock.Analyzer,
-		defers.Analyzer,
-		directive.Analyzer,
-		errorsas.Analyzer,
-		framepointer.Analyzer,
-		httpresponse.Analyzer,
-		hostport.Analyzer,
-		ifaceassert.Analyzer,
-		loopclosure.Analyzer,
-		lostcancel.Analyzer,
-		nilfunc.Analyzer,
-		printf.Analyzer,
-		shift.Analyzer,
-		sigchanyzer.Analyzer,
-		slog.Analyzer,
-		stdmethods.Analyzer,
-		stdversion.Analyzer,
-		stringintconv.Analyzer,
-		structtag.Analyzer,
-		tests.Analyzer,
-		testinggoroutine.Analyzer,
-		timeformat.Analyzer,
-		unmarshal.Analyzer,
-		unreachable.Analyzer,
-		unsafeptr.Analyzer,
-		unusedresult.Analyzer,
-		waitgroup.Analyzer,
-	)
 
-	// It's possible that unitchecker will exit early. In
-	// those cases the flags won't be counted.
-	counter.CountFlags("vet/flag:", *flag.CommandLine)
+	unitchecker.Main(suite...) // (never returns)
+}
+
+// The vet suite analyzers report diagnostics.
+// (Diagnostics must describe real problems, but need not
+// suggest fixes, and fixes are not necessarily safe to apply.)
+var suite = []*analysis.Analyzer{
+	appends.Analyzer,
+	asmdecl.Analyzer,
+	assign.Analyzer,
+	atomic.Analyzer,
+	bools.Analyzer,
+	buildtag.Analyzer,
+	cgocall.Analyzer,
+	composite.Analyzer,
+	copylock.Analyzer,
+	defers.Analyzer,
+	directive.Analyzer,
+	errorsas.Analyzer,
+	// fieldalignment.Analyzer omitted: too noisy
+	framepointer.Analyzer,
+	httpresponse.Analyzer,
+	hostport.Analyzer,
+	ifaceassert.Analyzer,
+	loopclosure.Analyzer,
+	lostcancel.Analyzer,
+	nilfunc.Analyzer,
+	printf.Analyzer,
+	// shadow.Analyzer omitted: too noisy
+	shift.Analyzer,
+	sigchanyzer.Analyzer,
+	slog.Analyzer,
+	stdmethods.Analyzer,
+	stdversion.Analyzer,
+	stringintconv.Analyzer,
+	structtag.Analyzer,
+	tests.Analyzer,
+	testinggoroutine.Analyzer,
+	timeformat.Analyzer,
+	unmarshal.Analyzer,
+	unreachable.Analyzer,
+	unsafeptr.Analyzer,
+	unusedresult.Analyzer,
+	waitgroup.Analyzer,
 }
diff --git a/src/cmd/vet/testdata/print/print.go b/src/cmd/vet/testdata/print/print.go
index e00222c42b5aef..3761da420bea3c 100644
--- a/src/cmd/vet/testdata/print/print.go
+++ b/src/cmd/vet/testdata/print/print.go
@@ -162,7 +162,7 @@ func PrintfTests() {
 	Printf("hi")                       // ok
 	const format = "%s %s\n"
 	Printf(format, "hi", "there")
-	Printf(format, "hi")              // ERROR "Printf format %s reads arg #2, but call has 1 arg$"
+	Printf(format, "hi")              // ERROR "Printf format %s reads arg #2, but call has 1 arg"
 	Printf("%s %d %.3v %q", "str", 4) // ERROR "Printf format %.3v reads arg #3, but call has 2 args"
 	f := new(ptrStringer)
 	f.Warn(0, "%s", "hello", 3)           // ERROR "Warn call has possible Printf formatting directive %s"
diff --git a/src/cmd/vet/vet_test.go b/src/cmd/vet/vet_test.go
index 54eabca938c3a9..0d509de528f247 100644
--- a/src/cmd/vet/vet_test.go
+++ b/src/cmd/vet/vet_test.go
@@ -28,7 +28,8 @@ func TestMain(m *testing.M) {
 		os.Exit(0)
 	}
 
-	os.Setenv("GO_VETTEST_IS_VET", "1") // Set for subprocesses to inherit.
+	// Set for subprocesses to inherit.
+	os.Setenv("GO_VETTEST_IS_VET", "1") // ignore error
 	os.Exit(m.Run())
 }
 
@@ -115,7 +116,7 @@ func TestVet(t *testing.T) {
 		cmd.Env = append(os.Environ(), "GOWORK=off")
 		cmd.Dir = "testdata/rangeloop"
 		cmd.Stderr = new(strings.Builder) // all vet output goes to stderr
-		cmd.Run()
+		cmd.Run()                         // ignore error
 		stderr := cmd.Stderr.(fmt.Stringer).String()
 
 		filename := filepath.FromSlash("testdata/rangeloop/rangeloop.go")
@@ -134,7 +135,7 @@ func TestVet(t *testing.T) {
 
 		if err := errorCheck(stderr, false, filename, filepath.Base(filename)); err != nil {
 			t.Errorf("error check failed: %s", err)
-			t.Log("vet stderr:\n", cmd.Stderr)
+			t.Logf("vet stderr:\n<<%s>>", cmd.Stderr)
 		}
 	})
 
@@ -146,7 +147,7 @@ func TestVet(t *testing.T) {
 		cmd.Env = append(os.Environ(), "GOWORK=off")
 		cmd.Dir = "testdata/stdversion"
 		cmd.Stderr = new(strings.Builder) // all vet output goes to stderr
-		cmd.Run()
+		cmd.Run()                         // ignore error
 		stderr := cmd.Stderr.(fmt.Stringer).String()
 
 		filename := filepath.FromSlash("testdata/stdversion/stdversion.go")
@@ -165,7 +166,7 @@ func TestVet(t *testing.T) {
 
 		if err := errorCheck(stderr, false, filename, filepath.Base(filename)); err != nil {
 			t.Errorf("error check failed: %s", err)
-			t.Log("vet stderr:\n", cmd.Stderr)
+			t.Logf("vet stderr:\n<<%s>>", cmd.Stderr)
 		}
 	})
 }
@@ -184,7 +185,7 @@ func cgoEnabled(t *testing.T) bool {
 func errchk(c *exec.Cmd, files []string, t *testing.T) {
 	output, err := c.CombinedOutput()
 	if _, ok := err.(*exec.ExitError); !ok {
-		t.Logf("vet output:\n%s", output)
+		t.Logf("vet output:\n<<%s>>", output)
 		t.Fatal(err)
 	}
 	fullshort := make([]string, 0, len(files)*2)
@@ -205,7 +206,6 @@ func TestTags(t *testing.T) {
 		"x testtag y": 1,
 		"othertag":    2,
 	} {
-		tag, wantFile := tag, wantFile
 		t.Run(tag, func(t *testing.T) {
 			t.Parallel()
 			t.Logf("-tags=%s", tag)
@@ -266,7 +266,7 @@ func errorCheck(outStr string, wantAuto bool, fullshort ...string) (err error) {
 			errmsgs, out = partitionStrings(we.prefix, out)
 		}
 		if len(errmsgs) == 0 {
-			errs = append(errs, fmt.Errorf("%s:%d: missing error %q", we.file, we.lineNum, we.reStr))
+			errs = append(errs, fmt.Errorf("%s:%d: missing error %q (prefix: %s)", we.file, we.lineNum, we.reStr, we.prefix))
 			continue
 		}
 		matched := false

From 69e82796322bbff60b522534a8a6eacb2bf1ebba Mon Sep 17 00:00:00 2001
From: Sean Liao 
Date: Wed, 8 Oct 2025 22:33:24 +0100
Subject: [PATCH 118/229] net/http: set cookie host to Request.Host when
 available

When both Request.URL and Request.Host are set, the host in URL
is used for connecting at the transport level, while Host is used
for the request host line. Cookies should be set for the request,
not the underlying connection destination.

Fixes #38988

Change-Id: I09053b87ccac67081f6038d205837d9763701526
Reviewed-on: https://go-review.googlesource.com/c/go/+/710335
Reviewed-by: Damien Neil 
Auto-Submit: Damien Neil 
Reviewed-by: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
---
 src/net/http/client.go      |  9 +++++++--
 src/net/http/client_test.go | 30 ++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/net/http/client.go b/src/net/http/client.go
index ba095ea1e34e5c..8faab2b17af01a 100644
--- a/src/net/http/client.go
+++ b/src/net/http/client.go
@@ -172,8 +172,13 @@ func refererForURL(lastReq, newReq *url.URL, explicitRef string) string {
 
 // didTimeout is non-nil only if err != nil.
 func (c *Client) send(req *Request, deadline time.Time) (resp *Response, didTimeout func() bool, err error) {
+	cookieURL := req.URL
+	if req.Host != "" {
+		cookieURL = cloneURL(cookieURL)
+		cookieURL.Host = req.Host
+	}
 	if c.Jar != nil {
-		for _, cookie := range c.Jar.Cookies(req.URL) {
+		for _, cookie := range c.Jar.Cookies(cookieURL) {
 			req.AddCookie(cookie)
 		}
 	}
@@ -183,7 +188,7 @@ func (c *Client) send(req *Request, deadline time.Time) (resp *Response, didTime
 	}
 	if c.Jar != nil {
 		if rc := resp.Cookies(); len(rc) > 0 {
-			c.Jar.SetCookies(req.URL, rc)
+			c.Jar.SetCookies(cookieURL, rc)
 		}
 	}
 	return resp, nil, nil
diff --git a/src/net/http/client_test.go b/src/net/http/client_test.go
index 94fddb508e0e38..2a3ee385f3c810 100644
--- a/src/net/http/client_test.go
+++ b/src/net/http/client_test.go
@@ -585,6 +585,36 @@ var echoCookiesRedirectHandler = HandlerFunc(func(w ResponseWriter, r *Request)
 	}
 })
 
+func TestHostMismatchCookies(t *testing.T) { run(t, testHostMismatchCookies) }
+func testHostMismatchCookies(t *testing.T, mode testMode) {
+	ts := newClientServerTest(t, mode, HandlerFunc(func(w ResponseWriter, r *Request) {
+		for _, c := range r.Cookies() {
+			c.Value = "SetOnServer"
+			SetCookie(w, c)
+		}
+	})).ts
+
+	reqURL, _ := url.Parse(ts.URL)
+	hostURL := *reqURL
+	hostURL.Host = "cookies.example.com"
+
+	c := ts.Client()
+	c.Jar = new(TestJar)
+	c.Jar.SetCookies(reqURL, []*Cookie{{Name: "First", Value: "SetOnClient"}})
+	c.Jar.SetCookies(&hostURL, []*Cookie{{Name: "Second", Value: "SetOnClient"}})
+
+	req, _ := NewRequest("GET", ts.URL, NoBody)
+	req.Host = hostURL.Host
+	resp, err := c.Do(req)
+	if err != nil {
+		t.Fatalf("Get: %v", err)
+	}
+	resp.Body.Close()
+
+	matchReturnedCookies(t, []*Cookie{{Name: "First", Value: "SetOnClient"}}, c.Jar.Cookies(reqURL))
+	matchReturnedCookies(t, []*Cookie{{Name: "Second", Value: "SetOnServer"}}, c.Jar.Cookies(&hostURL))
+}
+
 func TestClientSendsCookieFromJar(t *testing.T) {
 	defer afterTest(t)
 	tr := &recordingTransport{}

From 584a89fe7455470b09643b30bdc3cc55bb75a552 Mon Sep 17 00:00:00 2001
From: cuishuang 
Date: Fri, 10 Oct 2025 11:47:13 +0800
Subject: [PATCH 119/229] all: omit unnecessary reassignment

The new version of Go has been optimized, and variables do not need
to be reassigned.

Change-Id: I0374b049271e53510f2b162f6821fb3595f2c8ff
Reviewed-on: https://go-review.googlesource.com/c/go/+/710835
Auto-Submit: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Alan Donovan 
Reviewed-by: Michael Pratt 
---
 src/encoding/base32/base32_test.go | 1 -
 src/encoding/xml/marshal_test.go   | 1 -
 src/io/fs/readdir_test.go          | 1 -
 src/testing/iotest/reader_test.go  | 1 -
 4 files changed, 4 deletions(-)

diff --git a/src/encoding/base32/base32_test.go b/src/encoding/base32/base32_test.go
index f5d3c49e38fbef..6f8d564def3c86 100644
--- a/src/encoding/base32/base32_test.go
+++ b/src/encoding/base32/base32_test.go
@@ -709,7 +709,6 @@ func TestBufferedDecodingPadding(t *testing.T) {
 	}
 
 	for _, testcase := range testcases {
-		testcase := testcase
 		pr, pw := io.Pipe()
 		go func() {
 			for _, chunk := range testcase.chunks {
diff --git a/src/encoding/xml/marshal_test.go b/src/encoding/xml/marshal_test.go
index b8bce7170a60b6..6c7e711aac0566 100644
--- a/src/encoding/xml/marshal_test.go
+++ b/src/encoding/xml/marshal_test.go
@@ -2561,7 +2561,6 @@ var closeTests = []struct {
 
 func TestClose(t *testing.T) {
 	for _, tt := range closeTests {
-		tt := tt
 		t.Run(tt.desc, func(t *testing.T) {
 			var out strings.Builder
 			enc := NewEncoder(&out)
diff --git a/src/io/fs/readdir_test.go b/src/io/fs/readdir_test.go
index 4c409ae7a010e2..b89706b893afd2 100644
--- a/src/io/fs/readdir_test.go
+++ b/src/io/fs/readdir_test.go
@@ -72,7 +72,6 @@ func TestFileInfoToDirEntry(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		test := test
 		t.Run(test.path, func(t *testing.T) {
 			fi, err := Stat(testFs, test.path)
 			if err != nil {
diff --git a/src/testing/iotest/reader_test.go b/src/testing/iotest/reader_test.go
index 1d222372caf384..cecfbfce4920c4 100644
--- a/src/testing/iotest/reader_test.go
+++ b/src/testing/iotest/reader_test.go
@@ -238,7 +238,6 @@ func TestErrReader(t *testing.T) {
 	}
 
 	for _, tt := range cases {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			n, err := ErrReader(tt.err).Read(nil)
 			if err != tt.err {

From aced4c79a2b2c60e464410cec1e5378d1011fa18 Mon Sep 17 00:00:00 2001
From: Sean Liao 
Date: Thu, 9 Oct 2025 02:26:02 +0100
Subject: [PATCH 120/229] net/http: strip request body headers on POST to GET
 redirects

According to WHATWG Fetch, when the body is dropped in a redirect,
headers that describe the body should also be dropped.
https://fetch.spec.whatwg.org/#http-redirect-fetch

Fixes #57273

Change-Id: I84598f69608e95c1b556ea0ce5953ed43bf2d824
Reviewed-on: https://go-review.googlesource.com/c/go/+/710395
Auto-Submit: Damien Neil 
Reviewed-by: Michael Pratt 
Reviewed-by: Damien Neil 
LUCI-TryBot-Result: Go LUCI 
---
 src/net/http/client.go      | 18 +++++++++++++-----
 src/net/http/client_test.go | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/src/net/http/client.go b/src/net/http/client.go
index 8faab2b17af01a..d6a801073553f7 100644
--- a/src/net/http/client.go
+++ b/src/net/http/client.go
@@ -690,8 +690,7 @@ func (c *Client) do(req *Request) (retres *Response, reterr error) {
 					stripSensitiveHeaders = true
 				}
 			}
-			copyHeaders(req, stripSensitiveHeaders)
-
+			copyHeaders(req, stripSensitiveHeaders, !includeBody)
 			// Add the Referer header from the most recent
 			// request URL to the new one, if it's not https->http:
 			if ref := refererForURL(reqs[len(reqs)-1].URL, req.URL, req.Header.Get("Referer")); ref != "" {
@@ -758,7 +757,7 @@ func (c *Client) do(req *Request) (retres *Response, reterr error) {
 // makeHeadersCopier makes a function that copies headers from the
 // initial Request, ireq. For every redirect, this function must be called
 // so that it can copy headers into the upcoming Request.
-func (c *Client) makeHeadersCopier(ireq *Request) func(req *Request, stripSensitiveHeaders bool) {
+func (c *Client) makeHeadersCopier(ireq *Request) func(req *Request, stripSensitiveHeaders, stripBodyHeaders bool) {
 	// The headers to copy are from the very initial request.
 	// We use a closured callback to keep a reference to these original headers.
 	var (
@@ -772,7 +771,7 @@ func (c *Client) makeHeadersCopier(ireq *Request) func(req *Request, stripSensit
 		}
 	}
 
-	return func(req *Request, stripSensitiveHeaders bool) {
+	return func(req *Request, stripSensitiveHeaders, stripBodyHeaders bool) {
 		// If Jar is present and there was some initial cookies provided
 		// via the request header, then we may need to alter the initial
 		// cookies as we follow redirects since each redirect may end up
@@ -810,12 +809,21 @@ func (c *Client) makeHeadersCopier(ireq *Request) func(req *Request, stripSensit
 		// (at least the safe ones).
 		for k, vv := range ireqhdr {
 			sensitive := false
+			body := false
 			switch CanonicalHeaderKey(k) {
 			case "Authorization", "Www-Authenticate", "Cookie", "Cookie2",
 				"Proxy-Authorization", "Proxy-Authenticate":
 				sensitive = true
+
+			case "Content-Encoding", "Content-Language", "Content-Location",
+				"Content-Type":
+				// Headers relating to the body which is removed for
+				// POST to GET redirects
+				// https://fetch.spec.whatwg.org/#http-redirect-fetch
+				body = true
+
 			}
-			if !(sensitive && stripSensitiveHeaders) {
+			if !(sensitive && stripSensitiveHeaders) && !(body && stripBodyHeaders) {
 				req.Header[k] = vv
 			}
 		}
diff --git a/src/net/http/client_test.go b/src/net/http/client_test.go
index 2a3ee385f3c810..d184f720319ce4 100644
--- a/src/net/http/client_test.go
+++ b/src/net/http/client_test.go
@@ -1621,6 +1621,39 @@ func testClientStripHeadersOnRepeatedRedirect(t *testing.T, mode testMode) {
 	}
 }
 
+func TestClientStripHeadersOnPostToGetRedirect(t *testing.T) {
+	run(t, testClientStripHeadersOnPostToGetRedirect)
+}
+func testClientStripHeadersOnPostToGetRedirect(t *testing.T, mode testMode) {
+	ts := newClientServerTest(t, mode, HandlerFunc(func(w ResponseWriter, r *Request) {
+		if r.Method == "POST" {
+			Redirect(w, r, "/redirected", StatusFound)
+			return
+		} else if r.Method != "GET" {
+			t.Errorf("unexpected request method: %v", r.Method)
+			return
+		}
+		for key, val := range r.Header {
+			if strings.HasPrefix(key, "Content-") {
+				t.Errorf("unexpected request body header after redirect: %v: %v", key, val)
+			}
+		}
+	})).ts
+
+	c := ts.Client()
+
+	req, _ := NewRequest("POST", ts.URL, strings.NewReader("hello world"))
+	req.Header.Set("Content-Encoding", "a")
+	req.Header.Set("Content-Language", "b")
+	req.Header.Set("Content-Length", "c")
+	req.Header.Set("Content-Type", "d")
+	res, err := c.Do(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer res.Body.Close()
+}
+
 // Issue 22233: copy host when Client follows a relative redirect.
 func TestClientCopyHostOnRedirect(t *testing.T) { run(t, testClientCopyHostOnRedirect) }
 func testClientCopyHostOnRedirect(t *testing.T, mode testMode) {

From e3be2d1b2b68d960398a343805f77052d5decb22 Mon Sep 17 00:00:00 2001
From: Sean Liao 
Date: Thu, 9 Oct 2025 01:56:09 +0100
Subject: [PATCH 121/229] net/url: disallow raw IPv6 addresses in host

RFC 3986 requires square brackets around IPv6 addresses.
Parse's acceptance of raw IPv6 addresses is non compliant,
and complicates splitting out a port.

Fixes #31024
Fixes #75223

Change-Id: I477dc420a7441cb33156627dbd5e46d88c677f1e
Reviewed-on: https://go-review.googlesource.com/c/go/+/710176
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Damien Neil 
Reviewed-by: Michael Pratt 
---
 src/net/url/url.go      |  4 +++-
 src/net/url/url_test.go | 23 +++--------------------
 2 files changed, 6 insertions(+), 21 deletions(-)

diff --git a/src/net/url/url.go b/src/net/url/url.go
index 6afa30f162bd25..a69754880149a9 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -698,7 +698,9 @@ func parseHost(host string) (string, error) {
 			return "", errors.New("invalid IP-literal")
 		}
 		return "[" + unescapedHostname + "]" + unescapedColonPort, nil
-	} else if i := strings.LastIndex(host, ":"); i != -1 {
+	} else if i := strings.Index(host, ":"); i != -1 {
+		// IPv4address / reg-name
+		// E.g. 1.2.3.4, 1.2.3.4:80, example.com, example.com:80
 		colonPort := host[i:]
 		if !validOptionalPort(colonPort) {
 			return "", fmt.Errorf("invalid port %q after host", colonPort)
diff --git a/src/net/url/url_test.go b/src/net/url/url_test.go
index 6084facacc0519..a7543d6fd40b1e 100644
--- a/src/net/url/url_test.go
+++ b/src/net/url/url_test.go
@@ -506,26 +506,6 @@ var urltests = []URLTest{
 		},
 		"",
 	},
-	{
-		// Malformed IPv6 but still accepted.
-		"http://2b01:e34:ef40:7730:8e70:5aff:fefe:edac:8080/foo",
-		&URL{
-			Scheme: "http",
-			Host:   "2b01:e34:ef40:7730:8e70:5aff:fefe:edac:8080",
-			Path:   "/foo",
-		},
-		"",
-	},
-	{
-		// Malformed IPv6 but still accepted.
-		"http://2b01:e34:ef40:7730:8e70:5aff:fefe:edac:/foo",
-		&URL{
-			Scheme: "http",
-			Host:   "2b01:e34:ef40:7730:8e70:5aff:fefe:edac:",
-			Path:   "/foo",
-		},
-		"",
-	},
 	{
 		"http://[2b01:e34:ef40:7730:8e70:5aff:fefe:edac]:8080/foo",
 		&URL{
@@ -735,6 +715,9 @@ var parseRequestURLTests = []struct {
 	{"https://[0:0::test.com]:80", false},
 	{"https://[2001:db8::test.com]", false},
 	{"https://[test.com]", false},
+	{"https://1:2:3:4:5:6:7:8", false},
+	{"https://1:2:3:4:5:6:7:8:80", false},
+	{"https://example.com:80:", false},
 }
 
 func TestParseRequestURI(t *testing.T) {

From e8a53538b473f1a7a92602675eda2d34f3887611 Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Thu, 9 Oct 2025 20:58:34 +0000
Subject: [PATCH 122/229] runtime: fail TestGoroutineLeakProfile on data race

Some of the programs in testdata/testgoroutineleakprofile have data
races because they were taken from a corpus that showcases general Go
concurrency bugs, not just leaked goroutines.

This causes some flakiness as tests might fail due to, for example, a
concurrent map access, even outside of race mode.

Let's just call data races a failure and fix them in the examples. As
far as I can tell, there are only two that show up consistently.

Fixes #75732.

Change-Id: I160b3a1cdce4c2de3f2320b68b4083292e02b557
Reviewed-on: https://go-review.googlesource.com/c/go/+/710756
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Carlos Amedee 
Auto-Submit: Michael Knyszek 
Reviewed-by: Cherry Mui 
---
 src/runtime/goroutineleakprofile_test.go      | 10 +++----
 .../testgoroutineleakprofile/goker/README.md  | 30 +++++++++++--------
 .../goker/cockroach1055.go                    |  4 +--
 .../goker/moby27782.go                        |  7 +++++
 4 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/src/runtime/goroutineleakprofile_test.go b/src/runtime/goroutineleakprofile_test.go
index 6e26bcab132831..f5d2dd6372e54e 100644
--- a/src/runtime/goroutineleakprofile_test.go
+++ b/src/runtime/goroutineleakprofile_test.go
@@ -487,7 +487,7 @@ func TestGoroutineLeakProfile(t *testing.T) {
 	testCases = append(testCases, patternTestCases...)
 
 	// Test cases must not panic or cause fatal exceptions.
-	failStates := regexp.MustCompile(`fatal|panic`)
+	failStates := regexp.MustCompile(`fatal|panic|DATA RACE`)
 
 	testApp := func(exepath string, testCases []testCase) {
 
@@ -520,9 +520,9 @@ func TestGoroutineLeakProfile(t *testing.T) {
 						t.Errorf("Test %s produced no output. Is the goroutine leak profile collected?", tcase.name)
 					}
 
-					// Zero tolerance policy for fatal exceptions or panics.
+					// Zero tolerance policy for fatal exceptions, panics, or data races.
 					if failStates.MatchString(runOutput) {
-						t.Errorf("unexpected fatal exception or panic!\noutput:\n%s\n\n", runOutput)
+						t.Errorf("unexpected fatal exception or panic\noutput:\n%s\n\n", runOutput)
 					}
 
 					output += runOutput + "\n\n"
@@ -540,7 +540,7 @@ func TestGoroutineLeakProfile(t *testing.T) {
 				unexpectedLeaks := make([]string, 0, len(foundLeaks))
 
 				// Parse every leak and check if it is expected (maybe as a flaky leak).
-			LEAKS:
+			leaks:
 				for _, leak := range foundLeaks {
 					// Check if the leak is expected.
 					// If it is, check whether it has been encountered before.
@@ -569,7 +569,7 @@ func TestGoroutineLeakProfile(t *testing.T) {
 						for flakyLeak := range tcase.flakyLeaks {
 							if flakyLeak.MatchString(leak) {
 								// The leak is flaky. Carry on to the next line.
-								continue LEAKS
+								continue leaks
 							}
 						}
 
diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/README.md b/src/runtime/testdata/testgoroutineleakprofile/goker/README.md
index 88c50e1e480a08..e6f8fe23f26c02 100644
--- a/src/runtime/testdata/testgoroutineleakprofile/goker/README.md
+++ b/src/runtime/testdata/testgoroutineleakprofile/goker/README.md
@@ -24,18 +24,22 @@ Jingling Xue (jingling@cse.unsw.edu.au):
 
 White paper: https://lujie.ac.cn/files/papers/GoBench.pdf
 
-The examples have been modified in order to run the goroutine leak
-profiler. Buggy snippets are moved from within a unit test to separate
-applications. Each is then independently executed, possibly as multiple
-copies within the same application in order to exercise more interleavings.
-Concurrently, the main program sets up a waiting period (typically 1ms), followed
-by a goroutine leak profile request. Other modifications may involve injecting calls
-to `runtime.Gosched()`, to more reliably exercise buggy interleavings, or reductions
-in waiting periods when calling `time.Sleep`, in order to reduce overall testing time.
-
-The resulting goroutine leak profile is analyzed to ensure that no unexpected leaks occurred,
-and that the expected leaks did occur. If the leak is flaky, the only purpose of the expected
-leak list is to protect against unexpected leaks.
+The examples have been modified in order to run the goroutine leak profiler.
+Buggy snippets are moved from within a unit test to separate applications.
+Each is then independently executed, possibly as multiple copies within the
+same application in order to exercise more interleavings. Concurrently, the
+main program sets up a waiting period (typically 1ms), followed by a goroutine
+leak profile request. Other modifications may involve injecting calls to
+`runtime.Gosched()`, to more reliably exercise buggy interleavings, or reductions
+in waiting periods when calling `time.Sleep`, in order to reduce overall testing
+time.
+
+The resulting goroutine leak profile is analyzed to ensure that no unexpecte
+leaks occurred, and that the expected leaks did occur. If the leak is flaky, the
+only purpose of the expected leak list is to protect against unexpected leaks.
+
+The examples have also been modified to remove data races, since those create flaky
+test failures, when really all we care about are leaked goroutines.
 
 The entries below document each of the corresponding leaks.
 
@@ -1844,4 +1848,4 @@ c.inbox <- <================> [<-c.inbox]
 .                             close(c.closed)
 .                             <-c.dispatcherLoopStopped
 ---------------------G1,G2 leak-------------------------------
-```
\ No newline at end of file
+```
diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1055.go b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1055.go
index 687baed25a2a44..87cf157996800e 100644
--- a/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1055.go
+++ b/src/runtime/testdata/testgoroutineleakprofile/goker/cockroach1055.go
@@ -44,9 +44,9 @@ func (s *Stopper_cockroach1055) SetStopped() {
 func (s *Stopper_cockroach1055) Quiesce() {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	s.draining = 1
+	atomic.StoreInt32(&s.draining, 1)
 	s.drain.Wait()
-	s.draining = 0
+	atomic.StoreInt32(&s.draining, 0)
 }
 
 func (s *Stopper_cockroach1055) Stop() {
diff --git a/src/runtime/testdata/testgoroutineleakprofile/goker/moby27782.go b/src/runtime/testdata/testgoroutineleakprofile/goker/moby27782.go
index 7b3398fd381210..9b53d9035ca1e1 100644
--- a/src/runtime/testdata/testgoroutineleakprofile/goker/moby27782.go
+++ b/src/runtime/testdata/testgoroutineleakprofile/goker/moby27782.go
@@ -208,6 +208,7 @@ func (container *Container_moby27782) Reset() {
 }
 
 type JSONFileLogger_moby27782 struct {
+	mu      sync.Mutex
 	readers map[*LogWatcher_moby27782]struct{}
 }
 
@@ -218,11 +219,17 @@ func (l *JSONFileLogger_moby27782) ReadLogs() *LogWatcher_moby27782 {
 }
 
 func (l *JSONFileLogger_moby27782) readLogs(logWatcher *LogWatcher_moby27782) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
 	l.readers[logWatcher] = struct{}{}
 	followLogs_moby27782(logWatcher)
 }
 
 func (l *JSONFileLogger_moby27782) Close() {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
 	for r := range l.readers {
 		r.Close()
 		delete(l.readers, r)

From 48bb7a61147c397d0f45c10bc21ba12fa9cec0ad Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Fri, 10 Oct 2025 17:08:20 -0400
Subject: [PATCH 123/229] cmd/compile: repair bisection behavior for
 float-to-unsigned conversion

My stab at a bisect-reproducer failed, but I verified that
it fixed the problem described in the issue.

Updates #75834

Change-Id: I9e0dfacd2bbd22cbc557e144920ee3417a48088c
Reviewed-on: https://go-review.googlesource.com/c/go/+/710997
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Cherry Mui 
---
 src/cmd/compile/internal/ssagen/ssa.go | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 57cd9084821237..e2ef33274577cc 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -2865,7 +2865,19 @@ func (s *state) conv(n ir.Node, v *ssa.Value, ft, tt *types.Type) *ssa.Value {
 	}
 
 	if ft.IsFloat() || tt.IsFloat() {
-		conv, ok := fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]
+		cft, ctt := s.concreteEtype(ft), s.concreteEtype(tt)
+		conv, ok := fpConvOpToSSA[twoTypes{cft, ctt}]
+		// there's a change to a conversion-op table, this restores the old behavior if ConvertHash is false.
+		// use salted hash to distinguish unsigned convert at a Pos from signed convert at a Pos
+		if ctt == types.TUINT32 && ft.IsFloat() && !base.ConvertHash.MatchPosWithInfo(n.Pos(), "U", nil) {
+			// revert to old behavior
+			conv.op1 = ssa.OpCvt64Fto64
+			if cft == types.TFLOAT32 {
+				conv.op1 = ssa.OpCvt32Fto64
+			}
+			conv.op2 = ssa.OpTrunc64to32
+
+		}
 		if s.config.RegSize == 4 && Arch.LinkArch.Family != sys.MIPS && !s.softFloat {
 			if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
 				conv = conv1
@@ -5862,6 +5874,7 @@ func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *
 	// cutoff:=1<<(intY_Size-1)
 	// if x < floatX(cutoff) {
 	// 	result = uintY(x) // bThen
+	//  // gated by ConvertHash, clamp negative inputs to zero
 	// 	if x < 0 { // unlikely
 	// 		result = 0 // bZero
 	// 	}
@@ -5879,7 +5892,8 @@ func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *
 	b.Likely = ssa.BranchLikely
 
 	var bThen, bZero *ssa.Block
-	newConversion := base.ConvertHash.MatchPos(n.Pos(), nil)
+	// use salted hash to distinguish unsigned convert at a Pos from signed convert at a Pos
+	newConversion := base.ConvertHash.MatchPosWithInfo(n.Pos(), "U", nil)
 	if newConversion {
 		bZero = s.f.NewBlock(ssa.BlockPlain)
 		bThen = s.f.NewBlock(ssa.BlockIf)

From b497a29d25b0f6f29bedaa92ac1d40a1ee5c0956 Mon Sep 17 00:00:00 2001
From: Joe Tsai 
Date: Mon, 6 Oct 2025 12:56:29 -0700
Subject: [PATCH 124/229] encoding/json: fix regression in quoted numbers under
 goexperiment.jsonv2

The legacy parsing of quoted numbers in v1 was according to
the Go grammar for a number, rather than
the JSON grammar for a number.
The former is a superset of the latter.

This is a historical mistake, but usages exist that depend on it.
We already have branches for StringifyWithLegacySemantics
to handle quoted nulls, so we can expand it to handle this.

Fixes #75619

Change-Id: Ic07802539b7cbe0e1f53bd0f7e9bb344a8447203
Reviewed-on: https://go-review.googlesource.com/c/go/+/709615
Reviewed-by: Damien Neil 
Auto-Submit: Joseph Tsai 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Pratt 
---
 src/encoding/json/decode_test.go       | 56 ++++++++++++++++++++++++++
 src/encoding/json/v2/arshal_default.go | 51 ++++++++++++++++++-----
 src/encoding/json/v2_decode_test.go    | 56 ++++++++++++++++++++++++++
 src/encoding/json/v2_options.go        |  4 +-
 4 files changed, 157 insertions(+), 10 deletions(-)

diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go
index d12495f90b7141..0b26b8eb91813b 100644
--- a/src/encoding/json/decode_test.go
+++ b/src/encoding/json/decode_test.go
@@ -1237,6 +1237,62 @@ var unmarshalTests = []struct {
 		out:      (chan int)(nil),
 		err:      &UnmarshalTypeError{Value: "number", Type: reflect.TypeFor[chan int](), Offset: 1},
 	},
+
+	// #75619
+	{
+		CaseName: Name("QuotedInt/GoSyntax"),
+		in:       `{"X": "-0000123"}`,
+		ptr: new(struct {
+			X int64 `json:",string"`
+		}),
+		out: struct {
+			X int64 `json:",string"`
+		}{-123},
+	},
+	{
+		CaseName: Name("QuotedInt/Invalid"),
+		in:       `{"X": "123 "}`,
+		ptr: new(struct {
+			X int64 `json:",string"`
+		}),
+		err: &UnmarshalTypeError{Value: "number 123 ", Type: reflect.TypeFor[int64](), Field: "X", Offset: int64(len(`{"X": "123 "`))},
+	},
+	{
+		CaseName: Name("QuotedUint/GoSyntax"),
+		in:       `{"X": "0000123"}`,
+		ptr: new(struct {
+			X uint64 `json:",string"`
+		}),
+		out: struct {
+			X uint64 `json:",string"`
+		}{123},
+	},
+	{
+		CaseName: Name("QuotedUint/Invalid"),
+		in:       `{"X": "0x123"}`,
+		ptr: new(struct {
+			X uint64 `json:",string"`
+		}),
+		err: &UnmarshalTypeError{Value: "number 0x123", Type: reflect.TypeFor[uint64](), Field: "X", Offset: int64(len(`{"X": "0x123"`))},
+	},
+	{
+		CaseName: Name("QuotedFloat/GoSyntax"),
+		in:       `{"X": "0x1_4p-2"}`,
+		ptr: new(struct {
+			X float64 `json:",string"`
+		}),
+		out: struct {
+			X float64 `json:",string"`
+		}{0x1_4p-2},
+	},
+	{
+		CaseName: Name("QuotedFloat/Invalid"),
+		in:       `{"X": "1.5e1_"}`,
+		ptr: new(struct {
+			X float64 `json:",string"`
+		}),
+		err: &UnmarshalTypeError{Value: "number 1.5e1_", Type: reflect.TypeFor[float64](), Field: "X", Offset: int64(len(`{"X": "1.5e1_"`))},
+	},
 }
 
 func TestMarshal(t *testing.T) {
diff --git a/src/encoding/json/v2/arshal_default.go b/src/encoding/json/v2/arshal_default.go
index c2307fa31d7fcc..078d345e1439c2 100644
--- a/src/encoding/json/v2/arshal_default.go
+++ b/src/encoding/json/v2/arshal_default.go
@@ -474,10 +474,21 @@ func makeIntArshaler(t reflect.Type) *arshaler {
 				break
 			}
 			val = jsonwire.UnquoteMayCopy(val, flags.IsVerbatim())
-			if uo.Flags.Get(jsonflags.StringifyWithLegacySemantics) && string(val) == "null" {
-				if !uo.Flags.Get(jsonflags.MergeWithLegacySemantics) {
-					va.SetInt(0)
+			if uo.Flags.Get(jsonflags.StringifyWithLegacySemantics) {
+				// For historical reasons, v1 parsed a quoted number
+				// according to the Go syntax and permitted a quoted null.
+				// See https://go.dev/issue/75619
+				n, err := strconv.ParseInt(string(val), 10, bits)
+				if err != nil {
+					if string(val) == "null" {
+						if !uo.Flags.Get(jsonflags.MergeWithLegacySemantics) {
+							va.SetInt(0)
+						}
+						return nil
+					}
+					return newUnmarshalErrorAfterWithValue(dec, t, errors.Unwrap(err))
 				}
+				va.SetInt(n)
 				return nil
 			}
 			fallthrough
@@ -561,10 +572,21 @@ func makeUintArshaler(t reflect.Type) *arshaler {
 				break
 			}
 			val = jsonwire.UnquoteMayCopy(val, flags.IsVerbatim())
-			if uo.Flags.Get(jsonflags.StringifyWithLegacySemantics) && string(val) == "null" {
-				if !uo.Flags.Get(jsonflags.MergeWithLegacySemantics) {
-					va.SetUint(0)
+			if uo.Flags.Get(jsonflags.StringifyWithLegacySemantics) {
+				// For historical reasons, v1 parsed a quoted number
+				// according to the Go syntax and permitted a quoted null.
+				// See https://go.dev/issue/75619
+				n, err := strconv.ParseUint(string(val), 10, bits)
+				if err != nil {
+					if string(val) == "null" {
+						if !uo.Flags.Get(jsonflags.MergeWithLegacySemantics) {
+							va.SetUint(0)
+						}
+						return nil
+					}
+					return newUnmarshalErrorAfterWithValue(dec, t, errors.Unwrap(err))
 				}
+				va.SetUint(n)
 				return nil
 			}
 			fallthrough
@@ -671,10 +693,21 @@ func makeFloatArshaler(t reflect.Type) *arshaler {
 			if !stringify {
 				break
 			}
-			if uo.Flags.Get(jsonflags.StringifyWithLegacySemantics) && string(val) == "null" {
-				if !uo.Flags.Get(jsonflags.MergeWithLegacySemantics) {
-					va.SetFloat(0)
+			if uo.Flags.Get(jsonflags.StringifyWithLegacySemantics) {
+				// For historical reasons, v1 parsed a quoted number
+				// according to the Go syntax and permitted a quoted null.
+				// See https://go.dev/issue/75619
+				n, err := strconv.ParseFloat(string(val), bits)
+				if err != nil {
+					if string(val) == "null" {
+						if !uo.Flags.Get(jsonflags.MergeWithLegacySemantics) {
+							va.SetFloat(0)
+						}
+						return nil
+					}
+					return newUnmarshalErrorAfterWithValue(dec, t, errors.Unwrap(err))
 				}
+				va.SetFloat(n)
 				return nil
 			}
 			if n, err := jsonwire.ConsumeNumber(val); n != len(val) || err != nil {
diff --git a/src/encoding/json/v2_decode_test.go b/src/encoding/json/v2_decode_test.go
index f9b0a60f47cfd5..28c57ec8bf5c73 100644
--- a/src/encoding/json/v2_decode_test.go
+++ b/src/encoding/json/v2_decode_test.go
@@ -1243,6 +1243,62 @@ var unmarshalTests = []struct {
 		out:      (chan int)(nil),
 		err:      &UnmarshalTypeError{Value: "number", Type: reflect.TypeFor[chan int]()},
 	},
+
+	// #75619
+	{
+		CaseName: Name("QuotedInt/GoSyntax"),
+		in:       `{"X": "-0000123"}`,
+		ptr: new(struct {
+			X int64 `json:",string"`
+		}),
+		out: struct {
+			X int64 `json:",string"`
+		}{-123},
+	},
+	{
+		CaseName: Name("QuotedInt/Invalid"),
+		in:       `{"X": "123 "}`,
+		ptr: new(struct {
+			X int64 `json:",string"`
+		}),
+		err: &UnmarshalTypeError{Value: "number 123 ", Type: reflect.TypeFor[int64](), Field: "X", Offset: int64(len(`{"X": `))},
+	},
+	{
+		CaseName: Name("QuotedUint/GoSyntax"),
+		in:       `{"X": "0000123"}`,
+		ptr: new(struct {
+			X uint64 `json:",string"`
+		}),
+		out: struct {
+			X uint64 `json:",string"`
+		}{123},
+	},
+	{
+		CaseName: Name("QuotedUint/Invalid"),
+		in:       `{"X": "0x123"}`,
+		ptr: new(struct {
+			X uint64 `json:",string"`
+		}),
+		err: &UnmarshalTypeError{Value: "number 0x123", Type: reflect.TypeFor[uint64](), Field: "X", Offset: int64(len(`{"X": `))},
+	},
+	{
+		CaseName: Name("QuotedFloat/GoSyntax"),
+		in:       `{"X": "0x1_4p-2"}`,
+		ptr: new(struct {
+			X float64 `json:",string"`
+		}),
+		out: struct {
+			X float64 `json:",string"`
+		}{0x1_4p-2},
+	},
+	{
+		CaseName: Name("QuotedFloat/Invalid"),
+		in:       `{"X": "1.5e1_"}`,
+		ptr: new(struct {
+			X float64 `json:",string"`
+		}),
+		err: &UnmarshalTypeError{Value: "number 1.5e1_", Type: reflect.TypeFor[float64](), Field: "X", Offset: int64(len(`{"X": `))},
+	},
 }
 
 func TestMarshal(t *testing.T) {
diff --git a/src/encoding/json/v2_options.go b/src/encoding/json/v2_options.go
index 4dea88ad7edaf6..819fe59f412c68 100644
--- a/src/encoding/json/v2_options.go
+++ b/src/encoding/json/v2_options.go
@@ -506,7 +506,9 @@ func ReportErrorsWithLegacySemantics(v bool) Options {
 // When marshaling, such Go values are serialized as their usual
 // JSON representation, but quoted within a JSON string.
 // When unmarshaling, such Go values must be deserialized from
-// a JSON string containing their usual JSON representation.
+// a JSON string containing their usual JSON representation or
+// Go number representation for that numeric kind.
+// Note that the Go number grammar is a superset of the JSON number grammar.
 // A JSON null quoted in a JSON string is a valid substitute for JSON null
 // while unmarshaling into a Go value that `string` takes effect on.
 //

From 8aa1efa223d7bd39faaabdfbf85882ed3942a6f4 Mon Sep 17 00:00:00 2001
From: Cherry Mui 
Date: Sat, 11 Oct 2025 10:36:49 -0400
Subject: [PATCH 125/229] cmd/link: in TestFallocate, only check number of
 blocks on Darwin

The number-of-blocks check was introduced when fixing a Darwin-
specific bug. On Darwin, the file allocation syscall is a bit
tricky. On Linux and BSDs, it is more straightforward and unlikely
to go wrong.

The test itself, on the other hand, is less reliable on Linux (and
perhaps BSDs), as it is considered less portable and is an
implementation detail of the file system.

Given these two reasons, only check it on Darwin.

Fixes #75795.

Change-Id: I3da891fd60a141c3eca5d0f5ec20c2cad65b8862
Reviewed-on: https://go-review.googlesource.com/c/go/+/711095
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
---
 src/cmd/link/internal/ld/fallocate_test.go | 25 ++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/cmd/link/internal/ld/fallocate_test.go b/src/cmd/link/internal/ld/fallocate_test.go
index 3c6b7ef752edd3..f463b5b63b3b69 100644
--- a/src/cmd/link/internal/ld/fallocate_test.go
+++ b/src/cmd/link/internal/ld/fallocate_test.go
@@ -10,6 +10,7 @@ import (
 	"errors"
 	"os"
 	"path/filepath"
+	"runtime"
 	"syscall"
 	"testing"
 )
@@ -53,12 +54,24 @@ func TestFallocate(t *testing.T) {
 		if got := stat.Size(); got != sz {
 			t.Errorf("unexpected file size: got %d, want %d", got, sz)
 		}
-		// The number of blocks must be enough for the requested size.
-		// We used to require an exact match, but it appears that
-		// some file systems allocate a few extra blocks in some cases.
-		// See issue #41127.
-		if got, want := stat.Sys().(*syscall.Stat_t).Blocks, (sz+511)/512; got < want {
-			t.Errorf("unexpected disk usage: got %d blocks, want at least %d", got, want)
+		if runtime.GOOS == "darwin" {
+			// Check the number of allocated blocks on Darwin. On Linux (and
+			// perhaps BSDs), stat's Blocks field may not be portable as it
+			// is an implementation detail of the file system. On Darwin, it
+			// is documented as "the actual number of blocks allocated for
+			// the file in 512-byte units".
+			// The check is introduced when fixing a Darwin-specific bug. On
+			// Darwin, the file allocation syscall is a bit tricky. On Linux
+			// and BSDs, it is more straightforward and unlikely to go wrong.
+			// Given these two reasons, only check it on Darwin.
+			//
+			// The number of blocks must be enough for the requested size.
+			// We used to require an exact match, but it appears that
+			// some file systems allocate a few extra blocks in some cases.
+			// See issue #41127.
+			if got, want := stat.Sys().(*syscall.Stat_t).Blocks, (sz+511)/512; got < want {
+				t.Errorf("unexpected disk usage: got %d blocks, want at least %d", got, want)
+			}
 		}
 		out.munmap()
 	}

From 1cd71689f2ed8f07031a0cc58fc3586ca501839f Mon Sep 17 00:00:00 2001
From: Roland Shoemaker 
Date: Thu, 9 Oct 2025 13:35:24 -0700
Subject: [PATCH 126/229] crypto/x509: rework fix for CVE-2025-58187

In CL 709854 we enabled strict validation for a number of properties of
domain names (and their constraints). This caused significant breakage,
since we didn't previously disallow the creation of certificates which
contained these malformed domains.

Rollback a number of the properties we enforced, making domainNameValid
only enforce the same properties that domainToReverseLabels does. Since
this also undoes some of the DoS protections our initial fix enabled,
this change also adds caching of constraints in isValid (which perhaps
is the fix we should've initially chosen).

Updates #75835
Fixes #75828

Change-Id: Ie6ca6b4f30e9b8a143692b64757f7bbf4671ed0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/710735
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Damien Neil 
---
 src/crypto/x509/name_constraints_test.go | 75 +++++++++++++++++++--
 src/crypto/x509/parser.go                | 57 +++++++++++-----
 src/crypto/x509/parser_test.go           | 84 +++++++++++++++++++++---
 src/crypto/x509/verify.go                | 53 ++++++++++-----
 src/crypto/x509/verify_test.go           |  2 +-
 5 files changed, 221 insertions(+), 50 deletions(-)

diff --git a/src/crypto/x509/name_constraints_test.go b/src/crypto/x509/name_constraints_test.go
index 831fcbc8d2eb82..a5851845164d10 100644
--- a/src/crypto/x509/name_constraints_test.go
+++ b/src/crypto/x509/name_constraints_test.go
@@ -1456,7 +1456,63 @@ var nameConstraintsTests = []nameConstraintsTest{
 		expectedError: "incompatible key usage",
 	},
 
-	// #77: if several EKUs are requested, satisfying any of them is sufficient.
+	// An invalid DNS SAN should be detected only at validation time so
+	// that we can process CA certificates in the wild that have invalid SANs.
+	// See https://github.com/golang/go/issues/23995
+
+	// #77: an invalid DNS or mail SAN will not be detected if name constraint
+	// checking is not triggered.
+	{
+		roots: make([]constraintsSpec, 1),
+		intermediates: [][]constraintsSpec{
+			{
+				{},
+			},
+		},
+		leaf: leafSpec{
+			sans: []string{"dns:this is invalid", "email:this @ is invalid"},
+		},
+	},
+
+	// #78: an invalid DNS SAN will be detected if any name constraint checking
+	// is triggered.
+	{
+		roots: []constraintsSpec{
+			{
+				bad: []string{"uri:"},
+			},
+		},
+		intermediates: [][]constraintsSpec{
+			{
+				{},
+			},
+		},
+		leaf: leafSpec{
+			sans: []string{"dns:this is invalid"},
+		},
+		expectedError: "cannot parse dnsName",
+	},
+
+	// #79: an invalid email SAN will be detected if any name constraint
+	// checking is triggered.
+	{
+		roots: []constraintsSpec{
+			{
+				bad: []string{"uri:"},
+			},
+		},
+		intermediates: [][]constraintsSpec{
+			{
+				{},
+			},
+		},
+		leaf: leafSpec{
+			sans: []string{"email:this @ is invalid"},
+		},
+		expectedError: "cannot parse rfc822Name",
+	},
+
+	// #80: if several EKUs are requested, satisfying any of them is sufficient.
 	{
 		roots: make([]constraintsSpec, 1),
 		intermediates: [][]constraintsSpec{
@@ -1471,7 +1527,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		requestedEKUs: []ExtKeyUsage{ExtKeyUsageClientAuth, ExtKeyUsageEmailProtection},
 	},
 
-	// #78: EKUs that are not asserted in VerifyOpts are not required to be
+	// #81: EKUs that are not asserted in VerifyOpts are not required to be
 	// nested.
 	{
 		roots: make([]constraintsSpec, 1),
@@ -1490,7 +1546,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		},
 	},
 
-	// #79: a certificate without SANs and CN is accepted in a constrained chain.
+	// #82: a certificate without SANs and CN is accepted in a constrained chain.
 	{
 		roots: []constraintsSpec{
 			{
@@ -1507,7 +1563,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		},
 	},
 
-	// #80: a certificate without SANs and with a CN that does not parse as a
+	// #83: a certificate without SANs and with a CN that does not parse as a
 	// hostname is accepted in a constrained chain.
 	{
 		roots: []constraintsSpec{
@@ -1526,7 +1582,7 @@ var nameConstraintsTests = []nameConstraintsTest{
 		},
 	},
 
-	// #81: a certificate with SANs and CN is accepted in a constrained chain.
+	// #84: a certificate with SANs and CN is accepted in a constrained chain.
 	{
 		roots: []constraintsSpec{
 			{
@@ -1544,7 +1600,14 @@ var nameConstraintsTests = []nameConstraintsTest{
 		},
 	},
 
-	// #82: URIs with IPv6 addresses with zones and ports are rejected
+	// #85: .example.com is an invalid DNS name, it should not match the
+	// constraint example.com.
+	{
+		roots:         []constraintsSpec{{ok: []string{"dns:example.com"}}},
+		leaf:          leafSpec{sans: []string{"dns:.example.com"}},
+		expectedError: "cannot parse dnsName \".example.com\"",
+	},
+	// #86: URIs with IPv6 addresses with zones and ports are rejected
 	{
 		roots: []constraintsSpec{
 			{
diff --git a/src/crypto/x509/parser.go b/src/crypto/x509/parser.go
index 9d6bfd6e95f949..680dcee203a828 100644
--- a/src/crypto/x509/parser.go
+++ b/src/crypto/x509/parser.go
@@ -413,14 +413,10 @@ func parseSANExtension(der cryptobyte.String) (dnsNames, emailAddresses []string
 			if err := isIA5String(email); err != nil {
 				return errors.New("x509: SAN rfc822Name is malformed")
 			}
-			parsed, ok := parseRFC2821Mailbox(email)
-			if !ok || (ok && !domainNameValid(parsed.domain, false)) {
-				return errors.New("x509: SAN rfc822Name is malformed")
-			}
 			emailAddresses = append(emailAddresses, email)
 		case nameTypeDNS:
 			name := string(data)
-			if err := isIA5String(name); err != nil || (err == nil && !domainNameValid(name, false)) {
+			if err := isIA5String(name); err != nil {
 				return errors.New("x509: SAN dNSName is malformed")
 			}
 			dnsNames = append(dnsNames, string(name))
@@ -430,9 +426,12 @@ func parseSANExtension(der cryptobyte.String) (dnsNames, emailAddresses []string
 				return errors.New("x509: SAN uniformResourceIdentifier is malformed")
 			}
 			uri, err := url.Parse(uriStr)
-			if err != nil || (err == nil && uri.Host != "" && !domainNameValid(uri.Host, false)) {
+			if err != nil {
 				return fmt.Errorf("x509: cannot parse URI %q: %s", uriStr, err)
 			}
+			if len(uri.Host) > 0 && !domainNameValid(uri.Host, false) {
+				return fmt.Errorf("x509: cannot parse URI %q: invalid domain", uriStr)
+			}
 			uris = append(uris, uri)
 		case nameTypeIP:
 			switch len(data) {
@@ -1296,36 +1295,58 @@ func ParseRevocationList(der []byte) (*RevocationList, error) {
 	return rl, nil
 }
 
-// domainNameValid does minimal domain name validity checking. In particular it
-// enforces the following properties:
-//   - names cannot have the trailing period
-//   - names can only have a leading period if constraint is true
-//   - names must be <= 253 characters
-//   - names cannot have empty labels
-//   - names cannot labels that are longer than 63 characters
-//
-// Note that this does not enforce the LDH requirements for domain names.
+// domainNameValid is an alloc-less version of the checks that
+// domainToReverseLabels does.
 func domainNameValid(s string, constraint bool) bool {
-	if len(s) == 0 && constraint {
+	// TODO(#75835): This function omits a number of checks which we
+	// really should be doing to enforce that domain names are valid names per
+	// RFC 1034. We previously enabled these checks, but this broke a
+	// significant number of certificates we previously considered valid, and we
+	// happily create via CreateCertificate (et al). We should enable these
+	// checks, but will need to gate them behind a GODEBUG.
+	//
+	// I have left the checks we previously enabled, noted with "TODO(#75835)" so
+	// that we can easily re-enable them once we unbreak everyone.
+
+	// TODO(#75835): this should only be true for constraints.
+	if len(s) == 0 {
 		return true
 	}
-	if len(s) == 0 || (!constraint && s[0] == '.') || s[len(s)-1] == '.' || len(s) > 253 {
+
+	// Do not allow trailing period (FQDN format is not allowed in SANs or
+	// constraints).
+	if s[len(s)-1] == '.' {
 		return false
 	}
+
+	// TODO(#75835): domains must have at least one label, cannot have
+	// a leading empty label, and cannot be longer than 253 characters.
+	// if len(s) == 0 || (!constraint && s[0] == '.') || len(s) > 253 {
+	// 	return false
+	// }
+
 	lastDot := -1
 	if constraint && s[0] == '.' {
 		s = s[1:]
 	}
 
 	for i := 0; i <= len(s); i++ {
+		if i < len(s) && (s[i] < 33 || s[i] > 126) {
+			// Invalid character.
+			return false
+		}
 		if i == len(s) || s[i] == '.' {
 			labelLen := i
 			if lastDot >= 0 {
 				labelLen -= lastDot + 1
 			}
-			if labelLen == 0 || labelLen > 63 {
+			if labelLen == 0 {
 				return false
 			}
+			// TODO(#75835): labels cannot be longer than 63 characters.
+			// if labelLen > 63 {
+			// 	return false
+			// }
 			lastDot = i
 		}
 	}
diff --git a/src/crypto/x509/parser_test.go b/src/crypto/x509/parser_test.go
index 1b553e362e48a0..d53b805b786990 100644
--- a/src/crypto/x509/parser_test.go
+++ b/src/crypto/x509/parser_test.go
@@ -5,6 +5,9 @@
 package x509
 
 import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
 	"encoding/asn1"
 	"encoding/pem"
 	"os"
@@ -260,7 +263,31 @@ func TestDomainNameValid(t *testing.T) {
 		constraint bool
 		valid      bool
 	}{
-		{"empty name, name", "", false, false},
+		// TODO(#75835): these tests are for stricter name validation, which we
+		// had to disable. Once we reenable these strict checks, behind a
+		// GODEBUG, we should add them back in.
+		// {"empty name, name", "", false, false},
+		// {"254 char label, name", strings.Repeat("a.a", 84) + "aaa", false, false},
+		// {"254 char label, constraint", strings.Repeat("a.a", 84) + "aaa", true, false},
+		// {"253 char label, name", strings.Repeat("a.a", 84) + "aa", false, false},
+		// {"253 char label, constraint", strings.Repeat("a.a", 84) + "aa", true, false},
+		// {"64 char single label, name", strings.Repeat("a", 64), false, false},
+		// {"64 char single label, constraint", strings.Repeat("a", 64), true, false},
+		// {"64 char label, name", "a." + strings.Repeat("a", 64), false, false},
+		// {"64 char label, constraint", "a." + strings.Repeat("a", 64), true, false},
+
+		// TODO(#75835): these are the inverse of the tests above, they should be removed
+		// once the strict checking is enabled.
+		{"254 char label, name", strings.Repeat("a.a", 84) + "aaa", false, true},
+		{"254 char label, constraint", strings.Repeat("a.a", 84) + "aaa", true, true},
+		{"253 char label, name", strings.Repeat("a.a", 84) + "aa", false, true},
+		{"253 char label, constraint", strings.Repeat("a.a", 84) + "aa", true, true},
+		{"64 char single label, name", strings.Repeat("a", 64), false, true},
+		{"64 char single label, constraint", strings.Repeat("a", 64), true, true},
+		{"64 char label, name", "a." + strings.Repeat("a", 64), false, true},
+		{"64 char label, constraint", "a." + strings.Repeat("a", 64), true, true},
+
+		// Check we properly enforce properties of domain names.
 		{"empty name, constraint", "", true, true},
 		{"empty label, name", "a..a", false, false},
 		{"empty label, constraint", "a..a", true, false},
@@ -274,23 +301,60 @@ func TestDomainNameValid(t *testing.T) {
 		{"trailing period, constraint", "a.", true, false},
 		{"bare label, name", "a", false, true},
 		{"bare label, constraint", "a", true, true},
-		{"254 char label, name", strings.Repeat("a.a", 84) + "aaa", false, false},
-		{"254 char label, constraint", strings.Repeat("a.a", 84) + "aaa", true, false},
-		{"253 char label, name", strings.Repeat("a.a", 84) + "aa", false, false},
-		{"253 char label, constraint", strings.Repeat("a.a", 84) + "aa", true, false},
-		{"64 char single label, name", strings.Repeat("a", 64), false, false},
-		{"64 char single label, constraint", strings.Repeat("a", 64), true, false},
 		{"63 char single label, name", strings.Repeat("a", 63), false, true},
 		{"63 char single label, constraint", strings.Repeat("a", 63), true, true},
-		{"64 char label, name", "a." + strings.Repeat("a", 64), false, false},
-		{"64 char label, constraint", "a." + strings.Repeat("a", 64), true, false},
 		{"63 char label, name", "a." + strings.Repeat("a", 63), false, true},
 		{"63 char label, constraint", "a." + strings.Repeat("a", 63), true, true},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			if tc.valid != domainNameValid(tc.dnsName, tc.constraint) {
+			valid := domainNameValid(tc.dnsName, tc.constraint)
+			if tc.valid != valid {
 				t.Errorf("domainNameValid(%q, %t) = %v; want %v", tc.dnsName, tc.constraint, !tc.valid, tc.valid)
 			}
+			// Also check that we enforce the same properties as domainToReverseLabels
+			trimmedName := tc.dnsName
+			if tc.constraint && len(trimmedName) > 1 && trimmedName[0] == '.' {
+				trimmedName = trimmedName[1:]
+			}
+			_, revValid := domainToReverseLabels(trimmedName)
+			if valid != revValid {
+				t.Errorf("domainNameValid(%q, %t) = %t != domainToReverseLabels(%q) = %t", tc.dnsName, tc.constraint, valid, trimmedName, revValid)
+			}
 		})
 	}
 }
+
+func TestRoundtripWeirdSANs(t *testing.T) {
+	// TODO(#75835): check that certificates we create with CreateCertificate that have malformed SAN values
+	// can be parsed by ParseCertificate. We should eventually restrict this, but for now we have to maintain
+	// this property as people have been relying on it.
+	k, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	badNames := []string{
+		"baredomain",
+		"baredomain.",
+		strings.Repeat("a", 255),
+		strings.Repeat("a", 65) + ".com",
+	}
+	tmpl := &Certificate{
+		EmailAddresses: badNames,
+		DNSNames:       badNames,
+	}
+	b, err := CreateCertificate(rand.Reader, tmpl, tmpl, &k.PublicKey, k)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = ParseCertificate(b)
+	if err != nil {
+		t.Fatalf("Couldn't roundtrip certificate: %v", err)
+	}
+}
+
+func FuzzDomainNameValid(f *testing.F) {
+	f.Fuzz(func(t *testing.T, data string) {
+		domainNameValid(data, false)
+		domainNameValid(data, true)
+	})
+}
diff --git a/src/crypto/x509/verify.go b/src/crypto/x509/verify.go
index 058153fbe73461..bf7e7ec058db2b 100644
--- a/src/crypto/x509/verify.go
+++ b/src/crypto/x509/verify.go
@@ -429,7 +429,7 @@ func domainToReverseLabels(domain string) (reverseLabels []string, ok bool) {
 	return reverseLabels, true
 }
 
-func matchEmailConstraint(mailbox rfc2821Mailbox, constraint string) (bool, error) {
+func matchEmailConstraint(mailbox rfc2821Mailbox, constraint string, reversedDomainsCache map[string][]string, reversedConstraintsCache map[string][]string) (bool, error) {
 	// If the constraint contains an @, then it specifies an exact mailbox
 	// name.
 	if strings.Contains(constraint, "@") {
@@ -442,10 +442,10 @@ func matchEmailConstraint(mailbox rfc2821Mailbox, constraint string) (bool, erro
 
 	// Otherwise the constraint is like a DNS constraint of the domain part
 	// of the mailbox.
-	return matchDomainConstraint(mailbox.domain, constraint)
+	return matchDomainConstraint(mailbox.domain, constraint, reversedDomainsCache, reversedConstraintsCache)
 }
 
-func matchURIConstraint(uri *url.URL, constraint string) (bool, error) {
+func matchURIConstraint(uri *url.URL, constraint string, reversedDomainsCache map[string][]string, reversedConstraintsCache map[string][]string) (bool, error) {
 	// From RFC 5280, Section 4.2.1.10:
 	// “a uniformResourceIdentifier that does not include an authority
 	// component with a host name specified as a fully qualified domain
@@ -474,7 +474,7 @@ func matchURIConstraint(uri *url.URL, constraint string) (bool, error) {
 		return false, fmt.Errorf("URI with IP (%q) cannot be matched against constraints", uri.String())
 	}
 
-	return matchDomainConstraint(host, constraint)
+	return matchDomainConstraint(host, constraint, reversedDomainsCache, reversedConstraintsCache)
 }
 
 func matchIPConstraint(ip net.IP, constraint *net.IPNet) (bool, error) {
@@ -491,16 +491,21 @@ func matchIPConstraint(ip net.IP, constraint *net.IPNet) (bool, error) {
 	return true, nil
 }
 
-func matchDomainConstraint(domain, constraint string) (bool, error) {
+func matchDomainConstraint(domain, constraint string, reversedDomainsCache map[string][]string, reversedConstraintsCache map[string][]string) (bool, error) {
 	// The meaning of zero length constraints is not specified, but this
 	// code follows NSS and accepts them as matching everything.
 	if len(constraint) == 0 {
 		return true, nil
 	}
 
-	domainLabels, ok := domainToReverseLabels(domain)
-	if !ok {
-		return false, fmt.Errorf("x509: internal error: cannot parse domain %q", domain)
+	domainLabels, found := reversedDomainsCache[domain]
+	if !found {
+		var ok bool
+		domainLabels, ok = domainToReverseLabels(domain)
+		if !ok {
+			return false, fmt.Errorf("x509: internal error: cannot parse domain %q", domain)
+		}
+		reversedDomainsCache[domain] = domainLabels
 	}
 
 	// RFC 5280 says that a leading period in a domain name means that at
@@ -514,9 +519,14 @@ func matchDomainConstraint(domain, constraint string) (bool, error) {
 		constraint = constraint[1:]
 	}
 
-	constraintLabels, ok := domainToReverseLabels(constraint)
-	if !ok {
-		return false, fmt.Errorf("x509: internal error: cannot parse domain %q", constraint)
+	constraintLabels, found := reversedConstraintsCache[constraint]
+	if !found {
+		var ok bool
+		constraintLabels, ok = domainToReverseLabels(constraint)
+		if !ok {
+			return false, fmt.Errorf("x509: internal error: cannot parse domain %q", constraint)
+		}
+		reversedConstraintsCache[constraint] = constraintLabels
 	}
 
 	if len(domainLabels) < len(constraintLabels) ||
@@ -637,6 +647,19 @@ func (c *Certificate) isValid(certType int, currentChain []*Certificate, opts *V
 		}
 	}
 
+	// Each time we do constraint checking, we need to check the constraints in
+	// the current certificate against all of the names that preceded it. We
+	// reverse these names using domainToReverseLabels, which is a relatively
+	// expensive operation. Since we check each name against each constraint,
+	// this requires us to do N*C calls to domainToReverseLabels (where N is the
+	// total number of names that preceed the certificate, and C is the total
+	// number of constraints in the certificate). By caching the results of
+	// calling domainToReverseLabels, we can reduce that to N+C calls at the
+	// cost of keeping all of the parsed names and constraints in memory until
+	// we return from isValid.
+	reversedDomainsCache := map[string][]string{}
+	reversedConstraintsCache := map[string][]string{}
+
 	if (certType == intermediateCertificate || certType == rootCertificate) &&
 		c.hasNameConstraints() {
 		toCheck := []*Certificate{}
@@ -657,20 +680,20 @@ func (c *Certificate) isValid(certType int, currentChain []*Certificate, opts *V
 
 					if err := c.checkNameConstraints(&comparisonCount, maxConstraintComparisons, "email address", name, mailbox,
 						func(parsedName, constraint any) (bool, error) {
-							return matchEmailConstraint(parsedName.(rfc2821Mailbox), constraint.(string))
+							return matchEmailConstraint(parsedName.(rfc2821Mailbox), constraint.(string), reversedDomainsCache, reversedConstraintsCache)
 						}, c.PermittedEmailAddresses, c.ExcludedEmailAddresses); err != nil {
 						return err
 					}
 
 				case nameTypeDNS:
 					name := string(data)
-					if _, ok := domainToReverseLabels(name); !ok {
+					if !domainNameValid(name, false) {
 						return fmt.Errorf("x509: cannot parse dnsName %q", name)
 					}
 
 					if err := c.checkNameConstraints(&comparisonCount, maxConstraintComparisons, "DNS name", name, name,
 						func(parsedName, constraint any) (bool, error) {
-							return matchDomainConstraint(parsedName.(string), constraint.(string))
+							return matchDomainConstraint(parsedName.(string), constraint.(string), reversedDomainsCache, reversedConstraintsCache)
 						}, c.PermittedDNSDomains, c.ExcludedDNSDomains); err != nil {
 						return err
 					}
@@ -684,7 +707,7 @@ func (c *Certificate) isValid(certType int, currentChain []*Certificate, opts *V
 
 					if err := c.checkNameConstraints(&comparisonCount, maxConstraintComparisons, "URI", name, uri,
 						func(parsedName, constraint any) (bool, error) {
-							return matchURIConstraint(parsedName.(*url.URL), constraint.(string))
+							return matchURIConstraint(parsedName.(*url.URL), constraint.(string), reversedDomainsCache, reversedConstraintsCache)
 						}, c.PermittedURIDomains, c.ExcludedURIDomains); err != nil {
 						return err
 					}
diff --git a/src/crypto/x509/verify_test.go b/src/crypto/x509/verify_test.go
index 5595f99ea5e43a..60a4cea9146adf 100644
--- a/src/crypto/x509/verify_test.go
+++ b/src/crypto/x509/verify_test.go
@@ -1352,7 +1352,7 @@ var nameConstraintTests = []struct {
 
 func TestNameConstraints(t *testing.T) {
 	for i, test := range nameConstraintTests {
-		result, err := matchDomainConstraint(test.domain, test.constraint)
+		result, err := matchDomainConstraint(test.domain, test.constraint, map[string][]string{}, map[string][]string{})
 
 		if err != nil && !test.expectError {
 			t.Errorf("unexpected error for test #%d: domain=%s, constraint=%s, err=%s", i, test.domain, test.constraint, err)

From 6bcd97d9f4386528aa85eb3cc27da0ed902de870 Mon Sep 17 00:00:00 2001
From: Julien Cretel 
Date: Wed, 1 Oct 2025 20:08:18 +0000
Subject: [PATCH 127/229] all: replace calls to errors.As with errors.AsType

This change replaces most occurrences (in code as well as in comments) of
errors.As with errors.AsType. It leaves the errors package and vendored
code untouched.

Change-Id: I3bde73f318a0b408bdb8f5a251494af15a13118a
GitHub-Last-Rev: 8aaaa36a5a12d2a6a90c6d51680464e1a3115139
GitHub-Pull-Request: golang/go#75698
Reviewed-on: https://go-review.googlesource.com/c/go/+/708495
Auto-Submit: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Alan Donovan 
Reviewed-by: Michael Pratt 
---
 src/cmd/compile/internal/types2/api_test.go   |  8 ++--
 src/cmd/go/internal/base/path.go              |  3 +-
 src/cmd/go/internal/doc/pkgsite.go            |  3 +-
 src/cmd/go/internal/fmtcmd/fmt.go             |  9 ++---
 src/cmd/go/internal/load/pkg.go               |  4 +-
 src/cmd/go/internal/modget/get.go             | 38 ++++++++++---------
 src/cmd/go/internal/modget/query.go           |  2 +-
 src/cmd/go/internal/modload/build.go          | 22 +++++------
 src/cmd/go/internal/modload/buildlist.go      |  2 +-
 src/cmd/go/internal/modload/edit.go           |  6 ++-
 src/cmd/go/internal/modload/import.go         |  4 +-
 src/cmd/go/internal/modload/list.go           |  6 +--
 src/cmd/go/internal/modload/load.go           | 20 +++++-----
 src/cmd/go/internal/modload/modfile.go        | 10 +++--
 src/cmd/go/internal/modload/query.go          |  2 +-
 src/cmd/go/internal/test/test.go              |  3 +-
 src/cmd/go/internal/test/testflag.go          |  4 +-
 .../go/internal/vcweb/vcstest/vcstest_test.go |  4 +-
 src/cmd/go/internal/vcweb/vcweb.go            |  4 +-
 src/cmd/go/internal/version/version.go        |  2 +-
 src/cmd/go/internal/vet/vetflag.go            |  2 +-
 src/cmd/go/internal/work/build.go             |  2 +-
 src/cmd/go/internal/work/exec.go              |  7 ++--
 .../bootstrap_test/experiment_toolid_test.go  |  2 +-
 src/cmd/internal/robustio/robustio_darwin.go  |  7 +---
 src/cmd/internal/robustio/robustio_flaky.go   |  3 +-
 src/cmd/internal/robustio/robustio_windows.go |  3 +-
 src/cmd/internal/script/engine.go             |  8 ++--
 .../internal/script/scripttest/scripttest.go  |  2 +-
 src/cmd/link/link_test.go                     | 12 +++---
 src/crypto/tls/conn.go                        |  4 +-
 src/crypto/tls/handshake_server.go            |  5 +--
 src/crypto/tls/handshake_server_test.go       |  3 +-
 src/crypto/tls/quic.go                        |  7 ++--
 src/crypto/tls/quic_test.go                   |  3 +-
 src/debug/buildinfo/buildinfo.go              |  2 +-
 src/encoding/json/jsontext/coder_test.go      |  2 +-
 src/encoding/json/jsontext/fuzz_test.go       |  7 ++--
 src/encoding/json/jsontext/state.go           |  3 +-
 src/encoding/json/v2/errors.go                |  3 +-
 src/encoding/json/v2/example_test.go          |  3 +-
 src/go/types/api_test.go                      |  8 ++--
 .../runtime/wasitest/testdata/tcpecho.go      |  3 +-
 src/internal/testenv/testenv_unix.go          |  3 +-
 src/io/fs/readdir_test.go                     |  4 +-
 src/log/log_test.go                           |  3 +-
 src/log/slog/logger_test.go                   |  3 +-
 src/net/dnsclient_unix.go                     |  3 +-
 src/net/dnsclient_unix_test.go                |  9 ++---
 src/net/http/h2_error_test.go                 | 17 ++++-----
 src/net/lookup_test.go                        | 10 ++---
 src/os/exec/exec_test.go                      | 10 ++---
 src/os/os_test.go                             |  3 +-
 src/runtime/pprof/proto_windows.go            |  3 +-
 src/testing/fstest/testfs.go                  |  2 +-
 src/testing/fstest/testfs_test.go             |  8 +++-
 src/text/template/exec_test.go                |  3 +-
 src/text/template/funcs.go                    |  2 +-
 58 files changed, 160 insertions(+), 180 deletions(-)

diff --git a/src/cmd/compile/internal/types2/api_test.go b/src/cmd/compile/internal/types2/api_test.go
index 0d3c8b8e3e5e0f..4b7012e6c45e9f 100644
--- a/src/cmd/compile/internal/types2/api_test.go
+++ b/src/cmd/compile/internal/types2/api_test.go
@@ -2468,8 +2468,8 @@ func TestInstantiateErrors(t *testing.T) {
 			t.Fatalf("Instantiate(%v, %v) returned nil error, want non-nil", T, test.targs)
 		}
 
-		var argErr *ArgumentError
-		if !errors.As(err, &argErr) {
+		argErr, ok := errors.AsType[*ArgumentError](err)
+		if !ok {
 			t.Fatalf("Instantiate(%v, %v): error is not an *ArgumentError", T, test.targs)
 		}
 
@@ -2484,8 +2484,8 @@ func TestArgumentErrorUnwrapping(t *testing.T) {
 		Index: 1,
 		Err:   Error{Msg: "test"},
 	}
-	var e Error
-	if !errors.As(err, &e) {
+	e, ok := errors.AsType[Error](err)
+	if !ok {
 		t.Fatalf("error %v does not wrap types.Error", err)
 	}
 	if e.Msg != "test" {
diff --git a/src/cmd/go/internal/base/path.go b/src/cmd/go/internal/base/path.go
index 5bb7bc3bde63e2..a7577f62e76898 100644
--- a/src/cmd/go/internal/base/path.go
+++ b/src/cmd/go/internal/base/path.go
@@ -55,8 +55,7 @@ func sameFile(path1, path2 string) bool {
 
 // ShortPathError rewrites the path in err using base.ShortPath, if err is a wrapped PathError.
 func ShortPathError(err error) error {
-	var pe *fs.PathError
-	if errors.As(err, &pe) {
+	if pe, ok := errors.AsType[*fs.PathError](err); ok {
 		pe.Path = ShortPath(pe.Path)
 	}
 	return err
diff --git a/src/cmd/go/internal/doc/pkgsite.go b/src/cmd/go/internal/doc/pkgsite.go
index 06289ac4fc9a8a..c173167b6329a4 100644
--- a/src/cmd/go/internal/doc/pkgsite.go
+++ b/src/cmd/go/internal/doc/pkgsite.go
@@ -81,8 +81,7 @@ func doPkgsite(urlPath, fragment string) error {
 	cmd.Stderr = os.Stderr
 
 	if err := cmd.Run(); err != nil {
-		var ee *exec.ExitError
-		if errors.As(err, &ee) {
+		if ee, ok := errors.AsType[*exec.ExitError](err); ok {
 			// Exit with the same exit status as pkgsite to avoid
 			// printing of "exit status" error messages.
 			// Any relevant messages have already been printed
diff --git a/src/cmd/go/internal/fmtcmd/fmt.go b/src/cmd/go/internal/fmtcmd/fmt.go
index 62b22f6bcfa407..83fba9661a66fc 100644
--- a/src/cmd/go/internal/fmtcmd/fmt.go
+++ b/src/cmd/go/internal/fmtcmd/fmt.go
@@ -68,11 +68,10 @@ func runFmt(ctx context.Context, cmd *base.Command, args []string) {
 			continue
 		}
 		if pkg.Error != nil {
-			var nogo *load.NoGoError
-			var embed *load.EmbedError
-			if (errors.As(pkg.Error, &nogo) || errors.As(pkg.Error, &embed)) && len(pkg.InternalAllGoFiles()) > 0 {
-				// Skip this error, as we will format
-				// all files regardless.
+			if _, ok := errors.AsType[*load.NoGoError](pkg.Error); ok {
+				// Skip this error, as we will format all files regardless.
+			} else if  _, ok := errors.AsType[*load.EmbedError](pkg.Error); ok && len(pkg.InternalAllGoFiles()) > 0 {
+				// Skip this error, as we will format all files regardless.
 			} else {
 				base.Errorf("%v", pkg.Error)
 				continue
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index 135d7579d65dff..a894affc844066 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -290,8 +290,8 @@ func (p *Package) setLoadPackageDataError(err error, path string, stk *ImportSta
 
 	// Replace (possibly wrapped) *build.NoGoError with *load.NoGoError.
 	// The latter is more specific about the cause.
-	var nogoErr *build.NoGoError
-	if errors.As(err, &nogoErr) {
+	nogoErr, ok := errors.AsType[*build.NoGoError](err)
+	if ok {
 		if p.Dir == "" && nogoErr.Dir != "" {
 			p.Dir = nogoErr.Dir
 		}
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index d8b1f83bf1d132..5017f878ed3647 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -1294,15 +1294,13 @@ func (r *resolver) loadPackages(ctx context.Context, patterns []string, findPack
 			continue
 		}
 
-		var (
-			importMissing *modload.ImportMissingError
-			ambiguous     *modload.AmbiguousImportError
-		)
-		if !errors.As(err, &importMissing) && !errors.As(err, &ambiguous) {
-			// The package, which is a dependency of something we care about, has some
-			// problem that we can't resolve with a version change.
-			// Leave the error for the final LoadPackages call.
-			continue
+		if _, ok := errors.AsType[*modload.ImportMissingError](err); !ok {
+			if _, ok := errors.AsType[*modload.AmbiguousImportError](err); !ok {
+				// The package, which is a dependency of something we care about, has some
+				// problem that we can't resolve with a version change.
+				// Leave the error for the final LoadPackages call.
+				continue
+			}
 		}
 
 		path := pkgPath
@@ -1674,7 +1672,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 				}
 
 				base.SetExitStatus(1)
-				if ambiguousErr := (*modload.AmbiguousImportError)(nil); errors.As(err, &ambiguousErr) {
+				if ambiguousErr, ok := errors.AsType[*modload.AmbiguousImportError](err); ok {
 					for _, m := range ambiguousErr.Modules {
 						relevantMods[m] |= hasPkg
 					}
@@ -1717,7 +1715,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 		i := i
 		r.work.Add(func() {
 			err := modload.CheckRetractions(ctx, retractions[i].m)
-			if retractErr := (*modload.ModuleRetractedError)(nil); errors.As(err, &retractErr) {
+			if _, ok := errors.AsType[*modload.ModuleRetractedError](err); ok {
 				retractions[i].message = err.Error()
 			}
 		})
@@ -1994,8 +1992,8 @@ func (r *resolver) updateBuildList(ctx context.Context, additions []module.Versi
 			toolchain.SwitchOrFatal(ctx, err)
 		}
 
-		var constraint *modload.ConstraintError
-		if !errors.As(err, &constraint) {
+		constraint, ok := errors.AsType[*modload.ConstraintError](err)
+		if !ok {
 			base.Fatal(err)
 		}
 
@@ -2066,8 +2064,11 @@ func reqsFromGoMod(f *modfile.File) []module.Version {
 // does not exist at the requested version, either because the module does not
 // exist at all or because it does not include that specific version.
 func isNoSuchModuleVersion(err error) bool {
-	var noMatch *modload.NoMatchingVersionError
-	return errors.Is(err, os.ErrNotExist) || errors.As(err, &noMatch)
+	if errors.Is(err, os.ErrNotExist) {
+		return true
+	}
+	_, ok := errors.AsType[*modload.NoMatchingVersionError](err)
+	return ok
 }
 
 // isNoSuchPackageVersion reports whether err indicates that the requested
@@ -2075,8 +2076,11 @@ func isNoSuchModuleVersion(err error) bool {
 // that could contain it exists at that version, or because every such module
 // that does exist does not actually contain the package.
 func isNoSuchPackageVersion(err error) bool {
-	var noPackage *modload.PackageNotInModuleError
-	return isNoSuchModuleVersion(err) || errors.As(err, &noPackage)
+	if isNoSuchModuleVersion(err) {
+		return true
+	}
+	_, ok := errors.AsType[*modload.PackageNotInModuleError](err)
+	return ok
 }
 
 // workspace represents the set of modules in a workspace.
diff --git a/src/cmd/go/internal/modget/query.go b/src/cmd/go/internal/modget/query.go
index db09947293c6dc..59f3023ffc4f41 100644
--- a/src/cmd/go/internal/modget/query.go
+++ b/src/cmd/go/internal/modget/query.go
@@ -283,7 +283,7 @@ func reportError(q *query, err error) {
 	// If err already mentions all of the relevant parts of q, just log err to
 	// reduce stutter. Otherwise, log both q and err.
 	//
-	// TODO(bcmills): Use errors.As to unpack these errors instead of parsing
+	// TODO(bcmills): Use errors.AsType to unpack these errors instead of parsing
 	// strings with regular expressions.
 
 	if !utf8.ValidString(q.pattern) || !utf8.ValidString(q.version) {
diff --git a/src/cmd/go/internal/modload/build.go b/src/cmd/go/internal/modload/build.go
index cb168d58a227bc..a8ab82d1ecb246 100644
--- a/src/cmd/go/internal/modload/build.go
+++ b/src/cmd/go/internal/modload/build.go
@@ -129,11 +129,10 @@ func addUpdate(ctx context.Context, m *modinfo.ModulePublic) {
 	}
 
 	info, err := Query(ctx, m.Path, "upgrade", m.Version, CheckAllowed)
-	var noVersionErr *NoMatchingVersionError
-	if errors.Is(err, ErrDisallowed) ||
+	if _, ok := errors.AsType[*NoMatchingVersionError](err); ok ||
 		errors.Is(err, fs.ErrNotExist) ||
-		errors.As(err, &noVersionErr) {
-		// Ignore "not found" and "no matching version" errors.
+		errors.Is(err, ErrDisallowed) {
+		// Ignore "no matching version" and "not found" errors.
 		// This means the proxy has no matching version or no versions at all.
 		//
 		// Ignore "disallowed" errors. This means the current version is
@@ -238,10 +237,10 @@ func addRetraction(ctx context.Context, m *modinfo.ModulePublic) {
 	}
 
 	err := CheckRetractions(ctx, module.Version{Path: m.Path, Version: m.Version})
-	var noVersionErr *NoMatchingVersionError
-	var retractErr *ModuleRetractedError
-	if err == nil || errors.Is(err, fs.ErrNotExist) || errors.As(err, &noVersionErr) {
-		// Ignore "not found" and "no matching version" errors.
+	if err == nil {
+		return
+	} else if _, ok := errors.AsType[*NoMatchingVersionError](err); ok || errors.Is(err, fs.ErrNotExist) {
+		// Ignore "no matching version" and "not found" errors.
 		// This means the proxy has no matching version or no versions at all.
 		//
 		// We should report other errors though. An attacker that controls the
@@ -250,7 +249,7 @@ func addRetraction(ctx context.Context, m *modinfo.ModulePublic) {
 		// hide versions, since the "list" and "latest" endpoints are not
 		// authenticated.
 		return
-	} else if errors.As(err, &retractErr) {
+	} else if retractErr, ok := errors.AsType[*ModuleRetractedError](err); ok {
 		if len(retractErr.Rationale) == 0 {
 			m.Retracted = []string{"retracted by module author"}
 		} else {
@@ -265,9 +264,8 @@ func addRetraction(ctx context.Context, m *modinfo.ModulePublic) {
 // author. m.Error is set if there's an error loading deprecation information.
 func addDeprecation(ctx context.Context, m *modinfo.ModulePublic) {
 	deprecation, err := CheckDeprecation(ctx, module.Version{Path: m.Path, Version: m.Version})
-	var noVersionErr *NoMatchingVersionError
-	if errors.Is(err, fs.ErrNotExist) || errors.As(err, &noVersionErr) {
-		// Ignore "not found" and "no matching version" errors.
+	if _, ok := errors.AsType[*NoMatchingVersionError](err); ok || errors.Is(err, fs.ErrNotExist) {
+		// Ignore "no matching version" and "not found" errors.
 		// This means the proxy has no matching version or no versions at all.
 		//
 		// We should report other errors though. An attacker that controls the
diff --git a/src/cmd/go/internal/modload/buildlist.go b/src/cmd/go/internal/modload/buildlist.go
index 086626042c95b7..cf64ee1dc210f9 100644
--- a/src/cmd/go/internal/modload/buildlist.go
+++ b/src/cmd/go/internal/modload/buildlist.go
@@ -922,7 +922,7 @@ func tidyPrunedRoots(ctx context.Context, mainModule module.Version, old *Requir
 			q.Add(func() {
 				skipModFile := true
 				_, _, _, _, err := importFromModules(ctx, pkg.path, tidy, nil, skipModFile)
-				if aie := (*AmbiguousImportError)(nil); errors.As(err, &aie) {
+				if _, ok := errors.AsType[*AmbiguousImportError](err); ok {
 					disambiguateRoot.Store(pkg.mod, true)
 				}
 			})
diff --git a/src/cmd/go/internal/modload/edit.go b/src/cmd/go/internal/modload/edit.go
index 153c21a90cc423..96d864545d042a 100644
--- a/src/cmd/go/internal/modload/edit.go
+++ b/src/cmd/go/internal/modload/edit.go
@@ -226,8 +226,10 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 		// conflict we discover from one or more of the original roots.
 		mg, upgradedRoots, err := extendGraph(ctx, rootPruning, roots, selectedRoot)
 		if err != nil {
-			var tooNew *gover.TooNewError
-			if mg == nil || errors.As(err, &tooNew) {
+			if mg == nil {
+				return orig, false, err
+			}
+			if _, ok := errors.AsType[*gover.TooNewError](err); ok {
 				return orig, false, err
 			}
 			// We're about to walk the entire extended module graph, so we will find
diff --git a/src/cmd/go/internal/modload/import.go b/src/cmd/go/internal/modload/import.go
index 83e7e037117a4d..392fe3edd77b52 100644
--- a/src/cmd/go/internal/modload/import.go
+++ b/src/cmd/go/internal/modload/import.go
@@ -410,7 +410,7 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 
 			root, isLocal, err := fetch(ctx, m)
 			if err != nil {
-				if sumErr := (*sumMissingError)(nil); errors.As(err, &sumErr) {
+				if _, ok := errors.AsType[*sumMissingError](err); ok {
 					// We are missing a sum needed to fetch a module in the build list.
 					// We can't verify that the package is unique, and we may not find
 					// the package at all. Keep checking other modules to decide which
@@ -549,7 +549,7 @@ func queryImport(ctx context.Context, path string, rs *Requirements) (module.Ver
 	for _, m := range mods {
 		root, isLocal, err := fetch(ctx, m)
 		if err != nil {
-			if sumErr := (*sumMissingError)(nil); errors.As(err, &sumErr) {
+			if _, ok := errors.AsType[*sumMissingError](err); ok {
 				return module.Version{}, &ImportMissingSumError{importPath: path}
 			}
 			return module.Version{}, err
diff --git a/src/cmd/go/internal/modload/list.go b/src/cmd/go/internal/modload/list.go
index b66e73a112cedd..803bab49ae96bb 100644
--- a/src/cmd/go/internal/modload/list.go
+++ b/src/cmd/go/internal/modload/list.go
@@ -305,13 +305,11 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 // modinfoError wraps an error to create an error message in
 // modinfo.ModuleError with minimal redundancy.
 func modinfoError(path, vers string, err error) *modinfo.ModuleError {
-	var nerr *NoMatchingVersionError
-	var merr *module.ModuleError
-	if errors.As(err, &nerr) {
+	if _, ok := errors.AsType[*NoMatchingVersionError](err); ok {
 		// NoMatchingVersionError contains the query, so we don't mention the
 		// query again in ModuleError.
 		err = &module.ModuleError{Path: path, Err: err}
-	} else if !errors.As(err, &merr) {
+	} else if _, ok := errors.AsType[*module.ModuleError](err); !ok {
 		// If the error does not contain path and version, wrap it in a
 		// module.ModuleError.
 		err = &module.ModuleError{Path: path, Version: vers, Err: err}
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index 413de8148fb79e..0d661eb2e7b0be 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -1304,7 +1304,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 		}
 
 		// Add importer information to checksum errors.
-		if sumErr := (*ImportMissingSumError)(nil); errors.As(pkg.err, &sumErr) {
+		if sumErr, ok := errors.AsType[*ImportMissingSumError](pkg.err); ok {
 			if importer := pkg.stack; importer != nil {
 				sumErr.importer = importer.path
 				sumErr.importerVersion = importer.mod.Version
@@ -1312,7 +1312,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 			}
 		}
 
-		if stdErr := (*ImportMissingError)(nil); errors.As(pkg.err, &stdErr) && stdErr.isStd {
+		if stdErr, ok := errors.AsType[*ImportMissingError](pkg.err); ok && stdErr.isStd {
 			// Add importer go version information to import errors of standard
 			// library packages arising from newer releases.
 			if importer := pkg.stack; importer != nil {
@@ -1384,7 +1384,7 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 	var maxTooNew *gover.TooNewError
 	for _, pkg := range ld.pkgs {
 		if pkg.err != nil {
-			if tooNew := (*gover.TooNewError)(nil); errors.As(pkg.err, &tooNew) {
+			if tooNew, ok := errors.AsType[*gover.TooNewError](pkg.err); ok {
 				if maxTooNew == nil || gover.Compare(tooNew.GoVersion, maxTooNew.GoVersion) > 0 {
 					maxTooNew = tooNew
 				}
@@ -1573,7 +1573,7 @@ func (ld *loader) resolveMissingImports(ctx context.Context) (modAddedBy map[mod
 			// we should only add the missing import once.
 			continue
 		}
-		if !errors.As(pkg.err, new(*ImportMissingError)) {
+		if _, ok := errors.AsType[*ImportMissingError](pkg.err); !ok {
 			// Leave other errors for Import or load.Packages to report.
 			continue
 		}
@@ -1584,8 +1584,7 @@ func (ld *loader) resolveMissingImports(ctx context.Context) (modAddedBy map[mod
 			var err error
 			mod, err = queryImport(ctx, pkg.path, ld.requirements)
 			if err != nil {
-				var ime *ImportMissingError
-				if errors.As(err, &ime) {
+				if ime, ok := errors.AsType[*ImportMissingError](err); ok {
 					for curstack := pkg.stack; curstack != nil; curstack = curstack.stack {
 						if LoaderState.MainModules.Contains(curstack.mod.Path) {
 							ime.ImportingMainModule = curstack.mod
@@ -1625,7 +1624,7 @@ func (ld *loader) resolveMissingImports(ctx context.Context) (modAddedBy map[mod
 		maxTooNewPkg *loadPkg
 	)
 	for _, pm := range pkgMods {
-		if tooNew := (*gover.TooNewError)(nil); errors.As(pm.pkg.err, &tooNew) {
+		if tooNew, ok := errors.AsType[*gover.TooNewError](pm.pkg.err); ok {
 			if maxTooNew == nil || gover.Compare(tooNew.GoVersion, maxTooNew.GoVersion) > 0 {
 				maxTooNew = tooNew
 				maxTooNewPkg = pm.pkg
@@ -1771,8 +1770,7 @@ func (ld *loader) preloadRootModules(ctx context.Context, rootPkgs []string) (ch
 			// full module graph.
 			m, _, _, _, err := importFromModules(ctx, path, ld.requirements, nil, ld.skipImportModFiles)
 			if err != nil {
-				var missing *ImportMissingError
-				if errors.As(err, &missing) && ld.ResolveMissingImports {
+				if _, ok := errors.AsType[*ImportMissingError](err); ok && ld.ResolveMissingImports {
 					// This package isn't provided by any selected module.
 					// If we can find it, it will be a new root dependency.
 					m, err = queryImport(ctx, path, ld.requirements)
@@ -2196,14 +2194,14 @@ func (ld *loader) checkTidyCompatibility(ctx context.Context, rs *Requirements,
 			// module that previously provided the package to a version that no
 			// longer does, or to a version for which the module source code (but
 			// not the go.mod file in isolation) has a checksum error.
-			if missing := (*ImportMissingError)(nil); errors.As(mismatch.err, &missing) {
+			if _, ok := errors.AsType[*ImportMissingError](mismatch.err); ok {
 				selected := module.Version{
 					Path:    pkg.mod.Path,
 					Version: mg.Selected(pkg.mod.Path),
 				}
 				ld.error(fmt.Errorf("%s loaded from %v,\n\tbut go %s would fail to locate it in %s", pkg.stackText(), pkg.mod, compatVersion, selected))
 			} else {
-				if ambiguous := (*AmbiguousImportError)(nil); errors.As(mismatch.err, &ambiguous) {
+				if _, ok := errors.AsType[*AmbiguousImportError](mismatch.err); ok {
 					// TODO: Is this check needed?
 				}
 				ld.error(fmt.Errorf("%s loaded from %v,\n\tbut go %s would fail to locate it:\n\t%v", pkg.stackText(), pkg.mod, compatVersion, mismatch.err))
diff --git a/src/cmd/go/internal/modload/modfile.go b/src/cmd/go/internal/modload/modfile.go
index fa2348d97baf25..3fdbdc7010b993 100644
--- a/src/cmd/go/internal/modload/modfile.go
+++ b/src/cmd/go/internal/modload/modfile.go
@@ -76,8 +76,7 @@ func ReadModFile(gomod string, fix modfile.VersionFixer) (data []byte, f *modfil
 }
 
 func shortPathErrorList(err error) error {
-	var el modfile.ErrorList
-	if errors.As(err, &el) {
+	if el, ok := errors.AsType[modfile.ErrorList](err); ok {
 		for i := range el {
 			el[i].Filename = base.ShortPath(el[i].Filename)
 		}
@@ -175,12 +174,15 @@ func (e *excludedError) Is(err error) bool { return err == ErrDisallowed }
 // its author.
 func CheckRetractions(ctx context.Context, m module.Version) (err error) {
 	defer func() {
-		if retractErr := (*ModuleRetractedError)(nil); err == nil || errors.As(err, &retractErr) {
+		if err == nil {
+			return
+		}
+		if _, ok := errors.AsType[*ModuleRetractedError](err); ok {
 			return
 		}
 		// Attribute the error to the version being checked, not the version from
 		// which the retractions were to be loaded.
-		if mErr := (*module.ModuleError)(nil); errors.As(err, &mErr) {
+		if mErr, ok := errors.AsType[*module.ModuleError](err); ok {
 			err = mErr.Err
 		}
 		err = &retractionLoadingError{m: m, err: err}
diff --git a/src/cmd/go/internal/modload/query.go b/src/cmd/go/internal/modload/query.go
index 94ee8bc955918c..b37a244fbbacdd 100644
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@@ -932,7 +932,7 @@ func queryPrefixModules(ctx context.Context, candidateModules []string, queryMod
 				if notExistErr == nil {
 					notExistErr = rErr
 				}
-			} else if iv := (*module.InvalidVersionError)(nil); errors.As(rErr, &iv) {
+			} else if _, ok := errors.AsType[*module.InvalidVersionError](rErr); ok {
 				if invalidVersion == nil {
 					invalidVersion = rErr
 				}
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index e667bd64f7997f..e225929add20c2 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -1741,8 +1741,7 @@ func (r *runTestActor) Act(b *work.Builder, ctx context.Context, a *work.Action)
 		} else if errors.Is(err, exec.ErrWaitDelay) {
 			fmt.Fprintf(cmd.Stdout, "*** Test I/O incomplete %v after exiting.\n", cmd.WaitDelay)
 		}
-		var ee *exec.ExitError
-		if len(out) == 0 || !errors.As(err, &ee) || !ee.Exited() {
+		if ee, ok := errors.AsType[*exec.ExitError](err); !ok || !ee.Exited() || len(out) == 0 {
 			// If there was no test output, print the exit status so that the reason
 			// for failure is clear.
 			fmt.Fprintf(cmd.Stdout, "%s\n", err)
diff --git a/src/cmd/go/internal/test/testflag.go b/src/cmd/go/internal/test/testflag.go
index fc2b22cb56a9ee..d6891a1d0b955b 100644
--- a/src/cmd/go/internal/test/testflag.go
+++ b/src/cmd/go/internal/test/testflag.go
@@ -261,7 +261,7 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 			break
 		}
 
-		if nf := (cmdflag.NonFlagError{}); errors.As(err, &nf) {
+		if nf, ok := errors.AsType[cmdflag.NonFlagError](err); ok {
 			if !inPkgList && packageNames != nil {
 				// We already saw the package list previously, and this argument is not
 				// a flag, so it — and everything after it — must be either a value for
@@ -296,7 +296,7 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 			inPkgList = false
 		}
 
-		if nd := (cmdflag.FlagNotDefinedError{}); errors.As(err, &nd) {
+		if nd, ok := errors.AsType[cmdflag.FlagNotDefinedError](err); ok {
 			// This is a flag we do not know. We must assume that any args we see
 			// after this might be flag arguments, not package names, so make
 			// packageNames non-nil to indicate that the package list is complete.
diff --git a/src/cmd/go/internal/vcweb/vcstest/vcstest_test.go b/src/cmd/go/internal/vcweb/vcstest/vcstest_test.go
index 67234ac20d4628..6a6a0eee57ce85 100644
--- a/src/cmd/go/internal/vcweb/vcstest/vcstest_test.go
+++ b/src/cmd/go/internal/vcweb/vcstest/vcstest_test.go
@@ -155,10 +155,10 @@ func TestScripts(t *testing.T) {
 				t.Log(buf)
 			}
 			if err != nil {
-				if notInstalled := (vcweb.ServerNotInstalledError{}); errors.As(err, ¬Installed) || errors.Is(err, exec.ErrNotFound) {
+				if _, ok := errors.AsType[vcweb.ServerNotInstalledError](err); ok || errors.Is(err, exec.ErrNotFound) {
 					t.Skip(err)
 				}
-				if skip := (vcweb.SkipError{}); errors.As(err, &skip) {
+				if skip, ok := errors.AsType[vcweb.SkipError](err); ok {
 					if skip.Msg == "" {
 						t.Skip("SKIP")
 					} else {
diff --git a/src/cmd/go/internal/vcweb/vcweb.go b/src/cmd/go/internal/vcweb/vcweb.go
index b81ff5e63de72a..4b4e127bb042e0 100644
--- a/src/cmd/go/internal/vcweb/vcweb.go
+++ b/src/cmd/go/internal/vcweb/vcweb.go
@@ -244,9 +244,9 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	})
 	if err != nil {
 		s.logger.Print(err)
-		if notFound := (ScriptNotFoundError{}); errors.As(err, ¬Found) {
+		if _, ok := errors.AsType[ScriptNotFoundError](err); ok {
 			http.NotFound(w, req)
-		} else if notInstalled := (ServerNotInstalledError{}); errors.As(err, ¬Installed) || errors.Is(err, exec.ErrNotFound) {
+		} else if _, ok := errors.AsType[ServerNotInstalledError](err); ok || errors.Is(err, exec.ErrNotFound) {
 			http.Error(w, err.Error(), http.StatusNotImplemented)
 		} else {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
diff --git a/src/cmd/go/internal/version/version.go b/src/cmd/go/internal/version/version.go
index c26dd42b4e1a08..781bc080e89fe4 100644
--- a/src/cmd/go/internal/version/version.go
+++ b/src/cmd/go/internal/version/version.go
@@ -168,7 +168,7 @@ func scanFile(file string, info fs.FileInfo, mustPrint bool) bool {
 	bi, err := buildinfo.ReadFile(file)
 	if err != nil {
 		if mustPrint {
-			if pathErr := (*os.PathError)(nil); errors.As(err, &pathErr) && filepath.Clean(pathErr.Path) == filepath.Clean(file) {
+			if pathErr, ok := errors.AsType[*os.PathError](err); ok && filepath.Clean(pathErr.Path) == filepath.Clean(file) {
 				fmt.Fprintf(os.Stderr, "%v\n", file)
 			} else {
 				// Skip errors for non-Go binaries.
diff --git a/src/cmd/go/internal/vet/vetflag.go b/src/cmd/go/internal/vet/vetflag.go
index 7ebd8c9bfd19eb..7342b99d6e36bb 100644
--- a/src/cmd/go/internal/vet/vetflag.go
+++ b/src/cmd/go/internal/vet/vetflag.go
@@ -160,7 +160,7 @@ func toolFlags(cmd *base.Command, args []string) (passToTool, packageNames []str
 			break
 		}
 
-		if nf := (cmdflag.NonFlagError{}); errors.As(err, &nf) {
+		if _, ok := errors.AsType[cmdflag.NonFlagError](err); ok {
 			// Everything from here on out — including the argument we just consumed —
 			// must be a package name.
 			packageNames = args
diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index adc98f93138007..fdb483d46f21d9 100644
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -705,7 +705,7 @@ func runInstall(ctx context.Context, cmd *base.Command, args []string) {
 				continue
 			}
 			haveErrors = true
-			if missingErr := (*modload.ImportMissingError)(nil); !errors.As(pkg.Error, &missingErr) {
+			if _, ok := errors.AsType[*modload.ImportMissingError](pkg.Error); !ok {
 				allMissingErrors = false
 				break
 			}
diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index fa6ddce24bed3c..703b4367db31ef 100644
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -169,9 +169,10 @@ func (b *Builder) Do(ctx context.Context, root *Action) {
 					a.Package.Incomplete = true
 				}
 			} else {
-				var ipe load.ImportPathError
-				if a.Package != nil && (!errors.As(err, &ipe) || ipe.ImportPath() != a.Package.ImportPath) {
-					err = fmt.Errorf("%s: %v", a.Package.ImportPath, err)
+				if a.Package != nil {
+					if ipe, ok := errors.AsType[load.ImportPathError](err); !ok || ipe.ImportPath() != a.Package.ImportPath {
+						err = fmt.Errorf("%s: %v", a.Package.ImportPath, err)
+					}
 				}
 				sh := b.Shell(a)
 				sh.Errorf("%s", err)
diff --git a/src/cmd/internal/bootstrap_test/experiment_toolid_test.go b/src/cmd/internal/bootstrap_test/experiment_toolid_test.go
index ff2379c8998c76..ca292b700861a9 100644
--- a/src/cmd/internal/bootstrap_test/experiment_toolid_test.go
+++ b/src/cmd/internal/bootstrap_test/experiment_toolid_test.go
@@ -97,7 +97,7 @@ func runCmd(t *testing.T, dir string, env []string, path string, args ...string)
 	cmd.Env = env
 	out, err := cmd.Output()
 	if err != nil {
-		if ee := (*exec.ExitError)(nil); errors.As(err, &ee) {
+		if ee, ok := errors.AsType[*exec.ExitError](err); ok {
 			out = append(out, ee.Stderr...)
 		}
 		t.Fatalf("%s failed:\n%s\n%s", cmd, out, err)
diff --git a/src/cmd/internal/robustio/robustio_darwin.go b/src/cmd/internal/robustio/robustio_darwin.go
index 99fd8ebc2fff18..69ea2479308dea 100644
--- a/src/cmd/internal/robustio/robustio_darwin.go
+++ b/src/cmd/internal/robustio/robustio_darwin.go
@@ -13,9 +13,6 @@ const errFileNotFound = syscall.ENOENT
 
 // isEphemeralError returns true if err may be resolved by waiting.
 func isEphemeralError(err error) bool {
-	var errno syscall.Errno
-	if errors.As(err, &errno) {
-		return errno == errFileNotFound
-	}
-	return false
+	errno, ok := errors.AsType[syscall.Errno](err)
+	return ok && errno == errFileNotFound
 }
diff --git a/src/cmd/internal/robustio/robustio_flaky.go b/src/cmd/internal/robustio/robustio_flaky.go
index c56e36ca62412a..ec1a2daea65852 100644
--- a/src/cmd/internal/robustio/robustio_flaky.go
+++ b/src/cmd/internal/robustio/robustio_flaky.go
@@ -31,8 +31,7 @@ func retry(f func() (err error, mayRetry bool)) error {
 			return err
 		}
 
-		var errno syscall.Errno
-		if errors.As(err, &errno) && (lowestErrno == 0 || errno < lowestErrno) {
+		if errno, ok := errors.AsType[syscall.Errno](err); ok && (lowestErrno == 0 || errno < lowestErrno) {
 			bestErr = err
 			lowestErrno = errno
 		} else if bestErr == nil {
diff --git a/src/cmd/internal/robustio/robustio_windows.go b/src/cmd/internal/robustio/robustio_windows.go
index 687dcb66f83d15..ad46ec5cfeb601 100644
--- a/src/cmd/internal/robustio/robustio_windows.go
+++ b/src/cmd/internal/robustio/robustio_windows.go
@@ -14,8 +14,7 @@ const errFileNotFound = syscall.ERROR_FILE_NOT_FOUND
 
 // isEphemeralError returns true if err may be resolved by waiting.
 func isEphemeralError(err error) bool {
-	var errno syscall.Errno
-	if errors.As(err, &errno) {
+	if errno, ok := errors.AsType[syscall.Errno](err); ok {
 		switch errno {
 		case syscall.ERROR_ACCESS_DENIED,
 			syscall.ERROR_FILE_NOT_FOUND,
diff --git a/src/cmd/internal/script/engine.go b/src/cmd/internal/script/engine.go
index eb9344f6e2a1eb..4607868379488a 100644
--- a/src/cmd/internal/script/engine.go
+++ b/src/cmd/internal/script/engine.go
@@ -185,7 +185,7 @@ func (e *Engine) Execute(s *State, file string, script *bufio.Reader, log io.Wri
 
 	var lineno int
 	lineErr := func(err error) error {
-		if errors.As(err, new(*CommandError)) {
+		if _, ok := errors.AsType[*CommandError](err); ok {
 			return err
 		}
 		return fmt.Errorf("%s:%d: %w", file, lineno, err)
@@ -283,7 +283,7 @@ func (e *Engine) Execute(s *State, file string, script *bufio.Reader, log io.Wri
 		// Run the command.
 		err = e.runCommand(s, cmd, impl)
 		if err != nil {
-			if stop := (stopError{}); errors.As(err, &stop) {
+			if stop, ok := errors.AsType[stopError](err); ok {
 				// Since the 'stop' command halts execution of the entire script,
 				// log its message separately from the section in which it appears.
 				err = endSection(true)
@@ -607,13 +607,13 @@ func checkStatus(cmd *command, err error) error {
 		return nil
 	}
 
-	if s := (stopError{}); errors.As(err, &s) {
+	if _, ok := errors.AsType[stopError](err); ok {
 		// This error originated in the Stop command.
 		// Propagate it as-is.
 		return cmdError(cmd, err)
 	}
 
-	if w := (waitError{}); errors.As(err, &w) {
+	if _, ok := errors.AsType[waitError](err); ok {
 		// This error was surfaced from a background process by a call to Wait.
 		// Add a call frame for Wait itself, but ignore its "want" field.
 		// (Wait itself cannot fail to wait on commands or else it would leak
diff --git a/src/cmd/internal/script/scripttest/scripttest.go b/src/cmd/internal/script/scripttest/scripttest.go
index bace662a6722fd..349201fd188c1b 100644
--- a/src/cmd/internal/script/scripttest/scripttest.go
+++ b/src/cmd/internal/script/scripttest/scripttest.go
@@ -89,7 +89,7 @@ func Run(t testing.TB, e *script.Engine, s *script.State, filename string, testS
 		return e.Execute(s, filename, bufio.NewReader(testScript), log)
 	}()
 
-	if skip := (skipError{}); errors.As(err, &skip) {
+	if skip, ok := errors.AsType[skipError](err); ok {
 		if skip.msg == "" {
 			t.Skip("SKIP")
 		} else {
diff --git a/src/cmd/link/link_test.go b/src/cmd/link/link_test.go
index 0125ba8e0f56be..31822d21f39d31 100644
--- a/src/cmd/link/link_test.go
+++ b/src/cmd/link/link_test.go
@@ -1532,11 +1532,13 @@ func TestFlagS(t *testing.T) {
 		}
 		cmd = testenv.Command(t, testenv.GoToolPath(t), "tool", "nm", exe)
 		out, err = cmd.CombinedOutput()
-		if err != nil && !errors.As(err, new(*exec.ExitError)) {
-			// Error exit is fine as it may have no symbols.
-			// On darwin we need to emit dynamic symbol references so it
-			// actually has some symbols, and nm succeeds.
-			t.Errorf("(mode=%s) go tool nm failed: %v\n%s", mode, err, out)
+		if err != nil {
+			if _, ok := errors.AsType[*exec.ExitError](err); !ok {
+				// Error exit is fine as it may have no symbols.
+				// On darwin we need to emit dynamic symbol references so it
+				// actually has some symbols, and nm succeeds.
+				t.Errorf("(mode=%s) go tool nm failed: %v\n%s", mode, err, out)
+			}
 		}
 		for _, s := range syms {
 			if bytes.Contains(out, []byte(s)) {
diff --git a/src/crypto/tls/conn.go b/src/crypto/tls/conn.go
index 09dc9ea94c939f..2de120a1329f87 100644
--- a/src/crypto/tls/conn.go
+++ b/src/crypto/tls/conn.go
@@ -1578,9 +1578,9 @@ func (c *Conn) handshakeContext(ctx context.Context) (ret error) {
 			// the handshake (RFC 9001, Section 5.7).
 			c.quicSetReadSecret(QUICEncryptionLevelApplication, c.cipherSuite, c.in.trafficSecret)
 		} else {
-			var a alert
 			c.out.Lock()
-			if !errors.As(c.out.err, &a) {
+			a, ok := errors.AsType[alert](c.out.err)
+			if !ok {
 				a = alertInternalError
 			}
 			c.out.Unlock()
diff --git a/src/crypto/tls/handshake_server.go b/src/crypto/tls/handshake_server.go
index 088c66fadb2a44..a2cf176a86c0d8 100644
--- a/src/crypto/tls/handshake_server.go
+++ b/src/crypto/tls/handshake_server.go
@@ -965,10 +965,9 @@ func (c *Conn) processCertsFromClient(certificate Certificate) error {
 
 		chains, err := certs[0].Verify(opts)
 		if err != nil {
-			var errCertificateInvalid x509.CertificateInvalidError
-			if errors.As(err, &x509.UnknownAuthorityError{}) {
+			if _, ok := errors.AsType[x509.UnknownAuthorityError](err); ok {
 				c.sendAlert(alertUnknownCA)
-			} else if errors.As(err, &errCertificateInvalid) && errCertificateInvalid.Reason == x509.Expired {
+			} else if errCertificateInvalid, ok := errors.AsType[x509.CertificateInvalidError](err); ok && errCertificateInvalid.Reason == x509.Expired {
 				c.sendAlert(alertCertificateExpired)
 			} else {
 				c.sendAlert(alertBadCertificate)
diff --git a/src/crypto/tls/handshake_server_test.go b/src/crypto/tls/handshake_server_test.go
index 941f2a3373feb9..43183db2a19770 100644
--- a/src/crypto/tls/handshake_server_test.go
+++ b/src/crypto/tls/handshake_server_test.go
@@ -403,8 +403,7 @@ func TestAlertForwarding(t *testing.T) {
 
 	err := Server(s, testConfig).Handshake()
 	s.Close()
-	var opErr *net.OpError
-	if !errors.As(err, &opErr) || opErr.Err != error(alertUnknownCA) {
+	if opErr, ok := errors.AsType[*net.OpError](err); !ok || opErr.Err != error(alertUnknownCA) {
 		t.Errorf("Got error: %s; expected: %s", err, error(alertUnknownCA))
 	}
 }
diff --git a/src/crypto/tls/quic.go b/src/crypto/tls/quic.go
index 3be479eb12f085..2ba2242b2d93d2 100644
--- a/src/crypto/tls/quic.go
+++ b/src/crypto/tls/quic.go
@@ -362,12 +362,11 @@ func quicError(err error) error {
 	if err == nil {
 		return nil
 	}
-	var ae AlertError
-	if errors.As(err, &ae) {
+	if _, ok := errors.AsType[AlertError](err); ok {
 		return err
 	}
-	var a alert
-	if !errors.As(err, &a) {
+	a, ok := errors.AsType[alert](err)
+	if !ok {
 		a = alertInternalError
 	}
 	// Return an error wrapping the original error and an AlertError.
diff --git a/src/crypto/tls/quic_test.go b/src/crypto/tls/quic_test.go
index f6e8c55d9d63e4..5f4b2b7707d01e 100644
--- a/src/crypto/tls/quic_test.go
+++ b/src/crypto/tls/quic_test.go
@@ -368,8 +368,7 @@ func TestQUICHandshakeError(t *testing.T) {
 	if !errors.Is(err, AlertError(alertBadCertificate)) {
 		t.Errorf("connection handshake terminated with error %q, want alertBadCertificate", err)
 	}
-	var e *CertificateVerificationError
-	if !errors.As(err, &e) {
+	if _, ok := errors.AsType[*CertificateVerificationError](err); !ok {
 		t.Errorf("connection handshake terminated with error %q, want CertificateVerificationError", err)
 	}
 }
diff --git a/src/debug/buildinfo/buildinfo.go b/src/debug/buildinfo/buildinfo.go
index 12e3b750d233a7..d202d5050a2786 100644
--- a/src/debug/buildinfo/buildinfo.go
+++ b/src/debug/buildinfo/buildinfo.go
@@ -67,7 +67,7 @@ const (
 // with module support.
 func ReadFile(name string) (info *BuildInfo, err error) {
 	defer func() {
-		if pathErr := (*fs.PathError)(nil); errors.As(err, &pathErr) {
+		if _, ok := errors.AsType[*fs.PathError](err); ok {
 			err = fmt.Errorf("could not read Go build info: %w", err)
 		} else if err != nil {
 			err = fmt.Errorf("could not read Go build info from %s: %w", name, err)
diff --git a/src/encoding/json/jsontext/coder_test.go b/src/encoding/json/jsontext/coder_test.go
index 4a9efb3b8f97a5..8602e3e7fff286 100644
--- a/src/encoding/json/jsontext/coder_test.go
+++ b/src/encoding/json/jsontext/coder_test.go
@@ -486,7 +486,7 @@ func testCoderInterleaved(t *testing.T, where jsontest.CasePos, modeName string,
 				// Retry as a ReadToken call.
 				expectError := dec.PeekKind() == '}' || dec.PeekKind() == ']'
 				if expectError {
-					if !errors.As(err, new(*SyntacticError)) {
+					if _, ok := errors.AsType[*SyntacticError](err); !ok {
 						t.Fatalf("%s: Decoder.ReadToken error is %T, want %T", where, err, new(SyntacticError))
 					}
 					tickTock = !tickTock
diff --git a/src/encoding/json/jsontext/fuzz_test.go b/src/encoding/json/jsontext/fuzz_test.go
index 60d16b9e27805c..3ad181d43416b8 100644
--- a/src/encoding/json/jsontext/fuzz_test.go
+++ b/src/encoding/json/jsontext/fuzz_test.go
@@ -53,9 +53,10 @@ func FuzzCoder(f *testing.F) {
 			} else {
 				val, err := dec.ReadValue()
 				if err != nil {
-					expectError := dec.PeekKind() == '}' || dec.PeekKind() == ']'
-					if expectError && errors.As(err, new(*SyntacticError)) {
-						continue
+					if expectError := dec.PeekKind() == '}' || dec.PeekKind() == ']'; expectError {
+						if _, ok := errors.AsType[*SyntacticError](err); ok {
+							continue
+						}
 					}
 					if err == io.EOF {
 						break
diff --git a/src/encoding/json/jsontext/state.go b/src/encoding/json/jsontext/state.go
index d214fd5190325e..538dfe32bfa9d2 100644
--- a/src/encoding/json/jsontext/state.go
+++ b/src/encoding/json/jsontext/state.go
@@ -24,8 +24,7 @@ import (
 // The name of a duplicate JSON object member can be extracted as:
 //
 //	err := ...
-//	var serr jsontext.SyntacticError
-//	if errors.As(err, &serr) && serr.Err == jsontext.ErrDuplicateName {
+//	if serr, ok := errors.AsType[jsontext.SyntacticError](err); ok && serr.Err == jsontext.ErrDuplicateName {
 //		ptr := serr.JSONPointer // JSON pointer to duplicate name
 //		name := ptr.LastToken() // duplicate name itself
 //		...
diff --git a/src/encoding/json/v2/errors.go b/src/encoding/json/v2/errors.go
index 9485d7b527793c..0f50d608c9ed27 100644
--- a/src/encoding/json/v2/errors.go
+++ b/src/encoding/json/v2/errors.go
@@ -28,8 +28,7 @@ import (
 // The name of an unknown JSON object member can be extracted as:
 //
 //	err := ...
-//	var serr json.SemanticError
-//	if errors.As(err, &serr) && serr.Err == json.ErrUnknownName {
+//	if serr, ok := errors.AsType[json.SemanticError](err); ok && serr.Err == json.ErrUnknownName {
 //		ptr := serr.JSONPointer // JSON pointer to unknown name
 //		name := ptr.LastToken() // unknown name itself
 //		...
diff --git a/src/encoding/json/v2/example_test.go b/src/encoding/json/v2/example_test.go
index c6bf0a864d8385..6d539bbd36b529 100644
--- a/src/encoding/json/v2/example_test.go
+++ b/src/encoding/json/v2/example_test.go
@@ -371,8 +371,7 @@ func Example_unknownMembers() {
 	// Specifying RejectUnknownMembers causes Unmarshal
 	// to reject the presence of any unknown members.
 	err = json.Unmarshal([]byte(input), new(Color), json.RejectUnknownMembers(true))
-	var serr *json.SemanticError
-	if errors.As(err, &serr) && serr.Err == json.ErrUnknownName {
+	if serr, ok := errors.AsType[*json.SemanticError](err); ok && serr.Err == json.ErrUnknownName {
 		fmt.Println("Unmarshal error:", serr.Err, strconv.Quote(serr.JSONPointer.LastToken()))
 	}
 
diff --git a/src/go/types/api_test.go b/src/go/types/api_test.go
index f7a98ae28061bb..2798b9e0c4eb47 100644
--- a/src/go/types/api_test.go
+++ b/src/go/types/api_test.go
@@ -2480,8 +2480,8 @@ func TestInstantiateErrors(t *testing.T) {
 			t.Fatalf("Instantiate(%v, %v) returned nil error, want non-nil", T, test.targs)
 		}
 
-		var argErr *ArgumentError
-		if !errors.As(err, &argErr) {
+		argErr, ok := errors.AsType[*ArgumentError](err)
+		if !ok {
 			t.Fatalf("Instantiate(%v, %v): error is not an *ArgumentError", T, test.targs)
 		}
 
@@ -2496,8 +2496,8 @@ func TestArgumentErrorUnwrapping(t *testing.T) {
 		Index: 1,
 		Err:   Error{Msg: "test"},
 	}
-	var e Error
-	if !errors.As(err, &e) {
+	e, ok := errors.AsType[Error](err)
+	if !ok {
 		t.Fatalf("error %v does not wrap types.Error", err)
 	}
 	if e.Msg != "test" {
diff --git a/src/internal/runtime/wasitest/testdata/tcpecho.go b/src/internal/runtime/wasitest/testdata/tcpecho.go
index 819e3526885642..6da56acba10a1c 100644
--- a/src/internal/runtime/wasitest/testdata/tcpecho.go
+++ b/src/internal/runtime/wasitest/testdata/tcpecho.go
@@ -62,8 +62,7 @@ func findListener() (net.Listener, error) {
 		l, err := net.FileListener(f)
 		f.Close()
 
-		var se syscall.Errno
-		switch errors.As(err, &se); se {
+		switch se, _ := errors.AsType[syscall.Errno](err); se {
 		case syscall.ENOTSOCK:
 			continue
 		case syscall.EBADF:
diff --git a/src/internal/testenv/testenv_unix.go b/src/internal/testenv/testenv_unix.go
index a629078842eadc..22eeca220da017 100644
--- a/src/internal/testenv/testenv_unix.go
+++ b/src/internal/testenv/testenv_unix.go
@@ -21,8 +21,7 @@ func syscallIsNotSupported(err error) bool {
 		return false
 	}
 
-	var errno syscall.Errno
-	if errors.As(err, &errno) {
+	if errno, ok := errors.AsType[syscall.Errno](err); ok {
 		switch errno {
 		case syscall.EPERM, syscall.EROFS:
 			// User lacks permission: either the call requires root permission and the
diff --git a/src/io/fs/readdir_test.go b/src/io/fs/readdir_test.go
index b89706b893afd2..b729bf27ac40ac 100644
--- a/src/io/fs/readdir_test.go
+++ b/src/io/fs/readdir_test.go
@@ -93,8 +93,8 @@ func TestFileInfoToDirEntry(t *testing.T) {
 }
 
 func errorPath(err error) string {
-	var perr *PathError
-	if !errors.As(err, &perr) {
+	perr, ok := errors.AsType[*PathError](err)
+	if !ok {
 		return ""
 	}
 	return perr.Path
diff --git a/src/log/log_test.go b/src/log/log_test.go
index 8cc05c5e647f95..5d5d38cc10dbae 100644
--- a/src/log/log_test.go
+++ b/src/log/log_test.go
@@ -272,8 +272,7 @@ func TestCallDepth(t *testing.T) {
 			cmd.Env = append(cmd.Environ(), envVar+"=1")
 
 			out, err := cmd.CombinedOutput()
-			var exitErr *exec.ExitError
-			if !errors.As(err, &exitErr) {
+			if _, ok := errors.AsType[*exec.ExitError](err); !ok {
 				t.Fatalf("expected exec.ExitError: %v", err)
 			}
 
diff --git a/src/log/slog/logger_test.go b/src/log/slog/logger_test.go
index bf645d9c4c6310..edacef13a4d518 100644
--- a/src/log/slog/logger_test.go
+++ b/src/log/slog/logger_test.go
@@ -303,8 +303,7 @@ func TestCallDepthConnection(t *testing.T) {
 			cmd.Env = append(cmd.Environ(), envVar+"=1")
 
 			out, err := cmd.CombinedOutput()
-			var exitErr *exec.ExitError
-			if !errors.As(err, &exitErr) {
+			if _, ok := errors.AsType[*exec.ExitError](err); !ok {
 				t.Fatalf("expected exec.ExitError: %v", err)
 			}
 
diff --git a/src/net/dnsclient_unix.go b/src/net/dnsclient_unix.go
index 5e060a6b489bf9..940fcccf7f2139 100644
--- a/src/net/dnsclient_unix.go
+++ b/src/net/dnsclient_unix.go
@@ -842,8 +842,7 @@ func (r *Resolver) goLookupPTR(ctx context.Context, addr string, order hostLooku
 	}
 	p, server, err := r.lookup(ctx, arpa, dnsmessage.TypePTR, conf)
 	if err != nil {
-		var dnsErr *DNSError
-		if errors.As(err, &dnsErr) && dnsErr.IsNotFound {
+		if dnsErr, ok := errors.AsType[*DNSError](err); ok && dnsErr.IsNotFound {
 			if order == hostLookupDNSFiles {
 				names := lookupStaticAddr(addr)
 				if len(names) > 0 {
diff --git a/src/net/dnsclient_unix_test.go b/src/net/dnsclient_unix_test.go
index 826b4daba1e7fd..fc1d40f18b6f9a 100644
--- a/src/net/dnsclient_unix_test.go
+++ b/src/net/dnsclient_unix_test.go
@@ -2627,8 +2627,7 @@ func TestLongDNSNames(t *testing.T) {
 				}
 
 				expectedErr := DNSError{Err: errNoSuchHost.Error(), Name: v.req, IsNotFound: true}
-				var dnsErr *DNSError
-				errors.As(err, &dnsErr)
+				dnsErr, _ := errors.AsType[*DNSError](err)
 				if dnsErr == nil || *dnsErr != expectedErr {
 					t.Errorf("%v: Lookup%v: unexpected error: %v", i, testName, err)
 				}
@@ -2820,8 +2819,7 @@ func TestLookupOrderFilesNoSuchHost(t *testing.T) {
 		}
 
 		expectedErr := DNSError{Err: errNoSuchHost.Error(), Name: testName, IsNotFound: true}
-		var dnsErr *DNSError
-		errors.As(err, &dnsErr)
+		dnsErr, _ := errors.AsType[*DNSError](err)
 		if dnsErr == nil || *dnsErr != expectedErr {
 			t.Errorf("Lookup%v: unexpected error: %v", v.name, err)
 		}
@@ -2853,8 +2851,7 @@ func TestExtendedRCode(t *testing.T) {
 
 	r := &Resolver{PreferGo: true, Dial: fake.DialContext}
 	_, _, err := r.tryOneName(context.Background(), getSystemDNSConfig(), "go.dev.", dnsmessage.TypeA)
-	var dnsErr *DNSError
-	if !(errors.As(err, &dnsErr) && dnsErr.Err == errServerMisbehaving.Error()) {
+	if dnsErr, ok := errors.AsType[*DNSError](err); !ok || dnsErr.Err != errServerMisbehaving.Error() {
 		t.Fatalf("r.tryOneName(): unexpected error: %v", err)
 	}
 }
diff --git a/src/net/http/h2_error_test.go b/src/net/http/h2_error_test.go
index 5e400683b415e7..e71825451a8e32 100644
--- a/src/net/http/h2_error_test.go
+++ b/src/net/http/h2_error_test.go
@@ -25,19 +25,18 @@ func (e externalStreamError) Error() string {
 }
 
 func TestStreamError(t *testing.T) {
-	var target externalStreamError
 	streamErr := http2streamError(42, http2ErrCodeProtocol)
-	ok := errors.As(streamErr, &target)
+	extStreamErr, ok := errors.AsType[externalStreamError](streamErr)
 	if !ok {
-		t.Fatalf("errors.As failed")
+		t.Fatalf("errors.AsType failed")
 	}
-	if target.StreamID != streamErr.StreamID {
-		t.Errorf("got StreamID %v, expected %v", target.StreamID, streamErr.StreamID)
+	if extStreamErr.StreamID != streamErr.StreamID {
+		t.Errorf("got StreamID %v, expected %v", extStreamErr.StreamID, streamErr.StreamID)
 	}
-	if target.Cause != streamErr.Cause {
-		t.Errorf("got Cause %v, expected %v", target.Cause, streamErr.Cause)
+	if extStreamErr.Cause != streamErr.Cause {
+		t.Errorf("got Cause %v, expected %v", extStreamErr.Cause, streamErr.Cause)
 	}
-	if uint32(target.Code) != uint32(streamErr.Code) {
-		t.Errorf("got Code %v, expected %v", target.Code, streamErr.Code)
+	if uint32(extStreamErr.Code) != uint32(streamErr.Code) {
+		t.Errorf("got Code %v, expected %v", extStreamErr.Code, streamErr.Code)
 	}
 }
diff --git a/src/net/lookup_test.go b/src/net/lookup_test.go
index 514cbd098ae772..2a774100a8ec67 100644
--- a/src/net/lookup_test.go
+++ b/src/net/lookup_test.go
@@ -1420,8 +1420,8 @@ func testLookupNoData(t *testing.T, prefix string) {
 			return
 		}
 
-		var dnsErr *DNSError
-		if errors.As(err, &dnsErr) {
+		dnsErr, ok := errors.AsType[*DNSError](err)
+		if ok {
 			succeeded := true
 			if !dnsErr.IsNotFound {
 				succeeded = false
@@ -1455,8 +1455,7 @@ func testLookupNoData(t *testing.T, prefix string) {
 func TestLookupPortNotFound(t *testing.T) {
 	allResolvers(t, func(t *testing.T) {
 		_, err := LookupPort("udp", "_-unknown-service-")
-		var dnsErr *DNSError
-		if !errors.As(err, &dnsErr) || !dnsErr.IsNotFound {
+		if dnsErr, ok := errors.AsType[*DNSError](err); !ok || !dnsErr.IsNotFound {
 			t.Fatalf("unexpected error: %v", err)
 		}
 	})
@@ -1475,8 +1474,7 @@ var tcpOnlyService = func() string {
 func TestLookupPortDifferentNetwork(t *testing.T) {
 	allResolvers(t, func(t *testing.T) {
 		_, err := LookupPort("udp", tcpOnlyService)
-		var dnsErr *DNSError
-		if !errors.As(err, &dnsErr) || !dnsErr.IsNotFound {
+		if dnsErr, ok := errors.AsType[*DNSError](err); !ok || !dnsErr.IsNotFound {
 			t.Fatalf("unexpected error: %v", err)
 		}
 	})
diff --git a/src/os/exec/exec_test.go b/src/os/exec/exec_test.go
index 3bded3dea604fb..1decebdc222d23 100644
--- a/src/os/exec/exec_test.go
+++ b/src/os/exec/exec_test.go
@@ -1378,8 +1378,8 @@ func TestWaitInterrupt(t *testing.T) {
 		// The child process should be reported as failed,
 		// and the grandchild will exit (or die by SIGPIPE) once the
 		// stderr pipe is closed.
-		if ee := new(*exec.ExitError); !errors.As(err, ee) {
-			t.Errorf("Wait error = %v; want %T", err, *ee)
+		if ee, ok := errors.AsType[*exec.ExitError](err); !ok {
+			t.Errorf("Wait error = %v; want %T", err, ee)
 		}
 	})
 
@@ -1423,8 +1423,8 @@ func TestWaitInterrupt(t *testing.T) {
 
 		// This command ignores SIGINT, sleeping until it is killed.
 		// Wait should return the usual error for a killed process.
-		if ee := new(*exec.ExitError); !errors.As(err, ee) {
-			t.Errorf("Wait error = %v; want %T", err, *ee)
+		if ee, ok := errors.AsType[*exec.ExitError](err); !ok {
+			t.Errorf("Wait error = %v; want %T", err, ee)
 		}
 	})
 
@@ -1471,7 +1471,7 @@ func TestWaitInterrupt(t *testing.T) {
 		t.Logf("stderr:\n%s", cmd.Stderr)
 		t.Logf("[%d] %v", cmd.Process.Pid, err)
 
-		if ee := new(*exec.ExitError); !errors.As(err, ee) {
+		if _, ok := errors.AsType[*exec.ExitError](err); !ok {
 			t.Errorf("Wait error = %v; want %v", err, ctx.Err())
 		}
 
diff --git a/src/os/os_test.go b/src/os/os_test.go
index 9f6eb13e1f96a9..536734901baff6 100644
--- a/src/os/os_test.go
+++ b/src/os/os_test.go
@@ -840,8 +840,7 @@ func TestReaddirOfFile(t *testing.T) {
 	if err == nil {
 		t.Error("Readdirnames succeeded; want non-nil error")
 	}
-	var pe *PathError
-	if !errors.As(err, &pe) || pe.Path != f.Name() {
+	if pe, ok := errors.AsType[*PathError](err); !ok || pe.Path != f.Name() {
 		t.Errorf("Readdirnames returned %q; want a PathError with path %q", err, f.Name())
 	}
 	if len(names) > 0 {
diff --git a/src/runtime/pprof/proto_windows.go b/src/runtime/pprof/proto_windows.go
index f4dc44bd078eac..3118e8911e28ec 100644
--- a/src/runtime/pprof/proto_windows.go
+++ b/src/runtime/pprof/proto_windows.go
@@ -67,8 +67,7 @@ func readMainModuleMapping() (start, end uint64, exe, buildID string, err error)
 func createModuleSnapshot() (syscall.Handle, error) {
 	for {
 		snap, err := syscall.CreateToolhelp32Snapshot(windows.TH32CS_SNAPMODULE|windows.TH32CS_SNAPMODULE32, uint32(syscall.Getpid()))
-		var errno syscall.Errno
-		if err != nil && errors.As(err, &errno) && errno == windows.ERROR_BAD_LENGTH {
+		if errno, ok := errors.AsType[syscall.Errno](err); ok && errno == windows.ERROR_BAD_LENGTH {
 			// When CreateToolhelp32Snapshot(SNAPMODULE|SNAPMODULE32, ...) fails
 			// with ERROR_BAD_LENGTH then it should be retried until it succeeds.
 			continue
diff --git a/src/testing/fstest/testfs.go b/src/testing/fstest/testfs.go
index 1fb84b892842cb..72830a09a727bd 100644
--- a/src/testing/fstest/testfs.go
+++ b/src/testing/fstest/testfs.go
@@ -29,7 +29,7 @@ import (
 // The contents of fsys must not change concurrently with TestFS.
 //
 // If TestFS finds any misbehaviors, it returns either the first error or a
-// list of errors. Use [errors.Is] or [errors.As] to inspect.
+// list of errors. Use [errors.Is] or [errors.AsType] to inspect.
 //
 // Typical usage inside a test is:
 //
diff --git a/src/testing/fstest/testfs_test.go b/src/testing/fstest/testfs_test.go
index d6d6d89b89fdaa..e3d7f1ab44d7b7 100644
--- a/src/testing/fstest/testfs_test.go
+++ b/src/testing/fstest/testfs_test.go
@@ -105,8 +105,12 @@ func TestTestFSWrappedErrors(t *testing.T) {
 
 	// TestFS is expected to return a list of errors.
 	// Enforce that the list can be extracted for browsing.
-	var errs interface{ Unwrap() []error }
-	if !errors.As(err, &errs) {
+	type wrapper interface{
+		error
+		Unwrap() []error
+	}
+	errs, ok := errors.AsType[wrapper](err)
+	if !ok {
 		t.Errorf("caller should be able to extract the errors as a list: %#v", err)
 	} else {
 		for _, err := range errs.Unwrap() {
diff --git a/src/text/template/exec_test.go b/src/text/template/exec_test.go
index 65440901a0b4ec..8665f3ad4987c2 100644
--- a/src/text/template/exec_test.go
+++ b/src/text/template/exec_test.go
@@ -1015,8 +1015,7 @@ func TestExecError_CustomError(t *testing.T) {
 	var b bytes.Buffer
 	err := tmpl.Execute(&b, nil)
 
-	var e *CustomError
-	if !errors.As(err, &e) {
+	if _, ok := errors.AsType[*CustomError](err); !ok {
 		t.Fatalf("expected custom error; got %s", err)
 	}
 }
diff --git a/src/text/template/funcs.go b/src/text/template/funcs.go
index c28c3ea2002d21..30b3243a5a8416 100644
--- a/src/text/template/funcs.go
+++ b/src/text/template/funcs.go
@@ -22,7 +22,7 @@ import (
 // return value evaluates to non-nil during execution, execution terminates and
 // Execute returns that error.
 //
-// Errors returned by Execute wrap the underlying error; call [errors.As] to
+// Errors returned by Execute wrap the underlying error; call [errors.AsType] to
 // unwrap them.
 //
 // When template execution invokes a function with an argument list, that list

From 0e64ee1286c092eca95b3ffcc5917d34f43d4c0f Mon Sep 17 00:00:00 2001
From: Joe Tsai 
Date: Fri, 10 Oct 2025 17:56:04 -0700
Subject: [PATCH 128/229] encoding/json/v2: report EOF for top-level values in
 UnmarshalDecode

The fully streaming UnmarshalJSONFrom method and UnmarshalFromFunc
introduce an edge case where they can encounter EOF in the stream,
where it should be reported upstream as EOF rather than
ErrUnexpectedEOF or be wrapped within a SemanticError.

This is not possible with other unmarshal methods since the
"json" package would read the appropriate JSON value
before calling the custom method or function.

To avoid custom unmarshal methods from encountering EOF,
check whether the stream is already at EOF for top-level values
before calling the custom method.

Also, when wrapping EOF within a SemanticError, convert it
to ErrUnexpectedEOF to better indicate that this is unexpected.

Fixes #75802

Change-Id: I001396734b7e95b5337f77b71326284974ee730a
Reviewed-on: https://go-review.googlesource.com/c/go/+/710877
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Johan Brandhorst-Satzkorn 
Reviewed-by: Michael Pratt 
Reviewed-by: Carlos Amedee 
---
 src/encoding/json/jsontext/decode.go   |  6 ++++
 src/encoding/json/v2/arshal.go         |  3 +-
 src/encoding/json/v2/arshal_funcs.go   |  4 +++
 src/encoding/json/v2/arshal_methods.go |  4 +++
 src/encoding/json/v2/arshal_test.go    | 40 +++++++++++++++++++++++++-
 src/encoding/json/v2/errors.go         | 16 +++++++++--
 6 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/src/encoding/json/jsontext/decode.go b/src/encoding/json/jsontext/decode.go
index f505de44684a51..511832f2ae0879 100644
--- a/src/encoding/json/jsontext/decode.go
+++ b/src/encoding/json/jsontext/decode.go
@@ -792,6 +792,12 @@ func (d *decoderState) CheckNextValue(last bool) error {
 	return nil
 }
 
+// AtEOF reports whether the decoder is at EOF.
+func (d *decoderState) AtEOF() bool {
+	_, err := d.consumeWhitespace(d.prevEnd)
+	return err == io.ErrUnexpectedEOF
+}
+
 // CheckEOF verifies that the input has no more data.
 func (d *decoderState) CheckEOF() error {
 	return d.checkEOF(d.prevEnd)
diff --git a/src/encoding/json/v2/arshal.go b/src/encoding/json/v2/arshal.go
index 6b4bcb0c74cf7c..573d26567f3368 100644
--- a/src/encoding/json/v2/arshal.go
+++ b/src/encoding/json/v2/arshal.go
@@ -440,8 +440,9 @@ func UnmarshalRead(in io.Reader, out any, opts ...Options) (err error) {
 // Unlike [Unmarshal] and [UnmarshalRead], decode options are ignored because
 // they must have already been specified on the provided [jsontext.Decoder].
 //
-// The input may be a stream of one or more JSON values,
+// The input may be a stream of zero or more JSON values,
 // where this only unmarshals the next JSON value in the stream.
+// If there are no more top-level JSON values, it reports [io.EOF].
 // The output must be a non-nil pointer.
 // See [Unmarshal] for details about the conversion of JSON into a Go value.
 func UnmarshalDecode(in *jsontext.Decoder, out any, opts ...Options) (err error) {
diff --git a/src/encoding/json/v2/arshal_funcs.go b/src/encoding/json/v2/arshal_funcs.go
index 673caf3c37693d..28916af948db6e 100644
--- a/src/encoding/json/v2/arshal_funcs.go
+++ b/src/encoding/json/v2/arshal_funcs.go
@@ -9,6 +9,7 @@ package json
 import (
 	"errors"
 	"fmt"
+	"io"
 	"reflect"
 	"sync"
 
@@ -306,6 +307,9 @@ func UnmarshalFromFunc[T any](fn func(*jsontext.Decoder, T) error) *Unmarshalers
 		fnc: func(dec *jsontext.Decoder, va addressableValue, uo *jsonopts.Struct) error {
 			xd := export.Decoder(dec)
 			prevDepth, prevLength := xd.Tokens.DepthLength()
+			if prevDepth == 1 && xd.AtEOF() {
+				return io.EOF // check EOF early to avoid fn reporting an EOF
+			}
 			xd.Flags.Set(jsonflags.WithinArshalCall | 1)
 			v, _ := reflect.TypeAssert[T](va.castTo(t))
 			err := fn(dec, v)
diff --git a/src/encoding/json/v2/arshal_methods.go b/src/encoding/json/v2/arshal_methods.go
index 2decd144dbeaf9..1621eadc080763 100644
--- a/src/encoding/json/v2/arshal_methods.go
+++ b/src/encoding/json/v2/arshal_methods.go
@@ -9,6 +9,7 @@ package json
 import (
 	"encoding"
 	"errors"
+	"io"
 	"reflect"
 
 	"encoding/json/internal"
@@ -302,6 +303,9 @@ func makeMethodArshaler(fncs *arshaler, t reflect.Type) *arshaler {
 			}
 			xd := export.Decoder(dec)
 			prevDepth, prevLength := xd.Tokens.DepthLength()
+			if prevDepth == 1 && xd.AtEOF() {
+				return io.EOF // check EOF early to avoid fn reporting an EOF
+			}
 			xd.Flags.Set(jsonflags.WithinArshalCall | 1)
 			unmarshaler, _ := reflect.TypeAssert[UnmarshalerFrom](va.Addr())
 			err := unmarshaler.UnmarshalJSONFrom(dec)
diff --git a/src/encoding/json/v2/arshal_test.go b/src/encoding/json/v2/arshal_test.go
index 75093345a3b93e..dc15c5a5f531b5 100644
--- a/src/encoding/json/v2/arshal_test.go
+++ b/src/encoding/json/v2/arshal_test.go
@@ -7833,7 +7833,8 @@ func TestUnmarshal(t *testing.T) {
 		})),
 		wantErr: EU(errSomeError).withType(0, T[unmarshalJSONv2Func]()),
 	}, {
-		name: jsontest.Name("Methods/Invalid/JSONv2/TooFew"),
+		name:  jsontest.Name("Methods/Invalid/JSONv2/TooFew"),
+		inBuf: `{}`,
 		inVal: addr(unmarshalJSONv2Func(func(*jsontext.Decoder) error {
 			return nil // do nothing
 		})),
@@ -9234,6 +9235,43 @@ func TestUnmarshalReuse(t *testing.T) {
 	})
 }
 
+type unmarshalerEOF struct{}
+
+func (unmarshalerEOF) UnmarshalJSONFrom(dec *jsontext.Decoder) error {
+	return io.EOF // should be wrapped and converted by Unmarshal to io.ErrUnexpectedEOF
+}
+
+// TestUnmarshalEOF verifies that io.EOF is only ever returned by
+// UnmarshalDecode for a top-level value.
+func TestUnmarshalEOF(t *testing.T) {
+	opts := WithUnmarshalers(UnmarshalFromFunc(func(dec *jsontext.Decoder, _ *struct{}) error {
+		return io.EOF // should be wrapped and converted by Unmarshal to io.ErrUnexpectedEOF
+	}))
+
+	for _, in := range []string{"", "[", "[null", "[null]"} {
+		for _, newOut := range []func() any{
+			func() any { return new(unmarshalerEOF) },
+			func() any { return new([]unmarshalerEOF) },
+			func() any { return new(struct{}) },
+			func() any { return new([]struct{}) },
+		} {
+			wantErr := io.ErrUnexpectedEOF
+			if gotErr := Unmarshal([]byte(in), newOut(), opts); !errors.Is(gotErr, wantErr) {
+				t.Errorf("Unmarshal = %v, want %v", gotErr, wantErr)
+			}
+			if gotErr := UnmarshalRead(strings.NewReader(in), newOut(), opts); !errors.Is(gotErr, wantErr) {
+				t.Errorf("Unmarshal = %v, want %v", gotErr, wantErr)
+			}
+			switch gotErr := UnmarshalDecode(jsontext.NewDecoder(strings.NewReader(in)), newOut(), opts); {
+			case in != "" && !errors.Is(gotErr, wantErr):
+				t.Errorf("Unmarshal = %v, want %v", gotErr, wantErr)
+			case in == "" && gotErr != io.EOF:
+				t.Errorf("Unmarshal = %v, want %v", gotErr, io.EOF)
+			}
+		}
+	}
+}
+
 type ReaderFunc func([]byte) (int, error)
 
 func (f ReaderFunc) Read(b []byte) (int, error) { return f(b) }
diff --git a/src/encoding/json/v2/errors.go b/src/encoding/json/v2/errors.go
index 0f50d608c9ed27..4421f8b821cb5c 100644
--- a/src/encoding/json/v2/errors.go
+++ b/src/encoding/json/v2/errors.go
@@ -10,6 +10,7 @@ import (
 	"cmp"
 	"errors"
 	"fmt"
+	"io"
 	"reflect"
 	"strconv"
 	"strings"
@@ -118,7 +119,7 @@ func newInvalidFormatError(c coder, t reflect.Type) error {
 // newMarshalErrorBefore wraps err in a SemanticError assuming that e
 // is positioned right before the next token or value, which causes an error.
 func newMarshalErrorBefore(e *jsontext.Encoder, t reflect.Type, err error) error {
-	return &SemanticError{action: "marshal", GoType: t, Err: err,
+	return &SemanticError{action: "marshal", GoType: t, Err: toUnexpectedEOF(err),
 		ByteOffset:  e.OutputOffset() + int64(export.Encoder(e).CountNextDelimWhitespace()),
 		JSONPointer: jsontext.Pointer(export.Encoder(e).AppendStackPointer(nil, +1))}
 }
@@ -134,7 +135,7 @@ func newUnmarshalErrorBefore(d *jsontext.Decoder, t reflect.Type, err error) err
 	if export.Decoder(d).Flags.Get(jsonflags.ReportErrorsWithLegacySemantics) {
 		k = d.PeekKind()
 	}
-	return &SemanticError{action: "unmarshal", GoType: t, Err: err,
+	return &SemanticError{action: "unmarshal", GoType: t, Err: toUnexpectedEOF(err),
 		ByteOffset:  d.InputOffset() + int64(export.Decoder(d).CountNextDelimWhitespace()),
 		JSONPointer: jsontext.Pointer(export.Decoder(d).AppendStackPointer(nil, +1)),
 		JSONKind:    k}
@@ -157,7 +158,7 @@ func newUnmarshalErrorBeforeWithSkipping(d *jsontext.Decoder, t reflect.Type, er
 // is positioned right after the previous token or value, which caused an error.
 func newUnmarshalErrorAfter(d *jsontext.Decoder, t reflect.Type, err error) error {
 	tokOrVal := export.Decoder(d).PreviousTokenOrValue()
-	return &SemanticError{action: "unmarshal", GoType: t, Err: err,
+	return &SemanticError{action: "unmarshal", GoType: t, Err: toUnexpectedEOF(err),
 		ByteOffset:  d.InputOffset() - int64(len(tokOrVal)),
 		JSONPointer: jsontext.Pointer(export.Decoder(d).AppendStackPointer(nil, -1)),
 		JSONKind:    jsontext.Value(tokOrVal).Kind()}
@@ -206,6 +207,7 @@ func newSemanticErrorWithPosition(c coder, t reflect.Type, prevDepth int, prevLe
 	if serr == nil {
 		serr = &SemanticError{Err: err}
 	}
+	serr.Err = toUnexpectedEOF(serr.Err)
 	var currDepth int
 	var currLength int64
 	var coderState interface{ AppendStackPointer([]byte, int) []byte }
@@ -432,3 +434,11 @@ func newDuplicateNameError(ptr jsontext.Pointer, quotedName []byte, offset int64
 		Err:         jsontext.ErrDuplicateName,
 	}
 }
+
+// toUnexpectedEOF converts [io.EOF] to [io.ErrUnexpectedEOF].
+func toUnexpectedEOF(err error) error {
+	if err == io.EOF {
+		return io.ErrUnexpectedEOF
+	}
+	return err
+}

From 9b8742f2e79438b9442afa4c0a0139d3937ea33f Mon Sep 17 00:00:00 2001
From: Keith Randall 
Date: Mon, 13 Oct 2025 09:39:06 -0700
Subject: [PATCH 129/229] cmd/compile: don't depend on arch-dependent
 conversions in the compiler

Leave those constant foldings for runtime, similar to how we do it
for NaN generation.

These are the only instances I could find in cmd/compile/..., using

objdump -d ../pkg/tool/darwin_arm64/compile| egrep "(fcvtz|>:)" | grep -B1 fcvt

(There are instances in other places, like runtime and reflect, but I don't
think those places would affect compiler output.)

Change-Id: I4113fe4570115e4765825cf442cb1fde97cf2f27
Reviewed-on: https://go-review.googlesource.com/c/go/+/711281
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: David Chase 
Reviewed-by: Keith Randall 
---
 .../compile/internal/ssa/_gen/generic.rules   |  8 ++--
 .../compile/internal/ssa/rewritegeneric.go    | 16 +++++++
 test/codegen/math.go                          | 45 +++++++++++++++++++
 3 files changed, 65 insertions(+), 4 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules
index 23ce21a8b2cc28..af9c24f53fd245 100644
--- a/src/cmd/compile/internal/ssa/_gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/_gen/generic.rules
@@ -50,10 +50,10 @@
 (Cvt32to64F  (Const32  [c])) => (Const64F [float64(c)])
 (Cvt64to32F  (Const64  [c])) => (Const32F [float32(c)])
 (Cvt64to64F  (Const64  [c])) => (Const64F [float64(c)])
-(Cvt32Fto32  (Const32F [c])) => (Const32  [int32(c)])
-(Cvt32Fto64  (Const32F [c])) => (Const64  [int64(c)])
-(Cvt64Fto32  (Const64F [c])) => (Const32  [int32(c)])
-(Cvt64Fto64  (Const64F [c])) => (Const64  [int64(c)])
+(Cvt32Fto32  (Const32F [c])) && c >= -1<<31 && c < 1<<31 => (Const32 [int32(c)])
+(Cvt32Fto64  (Const32F [c])) && c >= -1<<63 && c < 1<<63 => (Const64 [int64(c)])
+(Cvt64Fto32  (Const64F [c])) && c >= -1<<31 && c < 1<<31 => (Const32 [int32(c)])
+(Cvt64Fto64  (Const64F [c])) && c >= -1<<63 && c < 1<<63 => (Const64 [int64(c)])
 (Round32F x:(Const32F)) => x
 (Round64F x:(Const64F)) => x
 (CvtBoolToUint8 (ConstBool [false])) => (Const8 [0])
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index c36ecc1cc60fcc..79c444a86b29df 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -6607,12 +6607,16 @@ func rewriteValuegeneric_OpCtz8(v *Value) bool {
 func rewriteValuegeneric_OpCvt32Fto32(v *Value) bool {
 	v_0 := v.Args[0]
 	// match: (Cvt32Fto32 (Const32F [c]))
+	// cond: c >= -1<<31 && c < 1<<31
 	// result: (Const32 [int32(c)])
 	for {
 		if v_0.Op != OpConst32F {
 			break
 		}
 		c := auxIntToFloat32(v_0.AuxInt)
+		if !(c >= -1<<31 && c < 1<<31) {
+			break
+		}
 		v.reset(OpConst32)
 		v.AuxInt = int32ToAuxInt(int32(c))
 		return true
@@ -6622,12 +6626,16 @@ func rewriteValuegeneric_OpCvt32Fto32(v *Value) bool {
 func rewriteValuegeneric_OpCvt32Fto64(v *Value) bool {
 	v_0 := v.Args[0]
 	// match: (Cvt32Fto64 (Const32F [c]))
+	// cond: c >= -1<<63 && c < 1<<63
 	// result: (Const64 [int64(c)])
 	for {
 		if v_0.Op != OpConst32F {
 			break
 		}
 		c := auxIntToFloat32(v_0.AuxInt)
+		if !(c >= -1<<63 && c < 1<<63) {
+			break
+		}
 		v.reset(OpConst64)
 		v.AuxInt = int64ToAuxInt(int64(c))
 		return true
@@ -6682,12 +6690,16 @@ func rewriteValuegeneric_OpCvt32to64F(v *Value) bool {
 func rewriteValuegeneric_OpCvt64Fto32(v *Value) bool {
 	v_0 := v.Args[0]
 	// match: (Cvt64Fto32 (Const64F [c]))
+	// cond: c >= -1<<31 && c < 1<<31
 	// result: (Const32 [int32(c)])
 	for {
 		if v_0.Op != OpConst64F {
 			break
 		}
 		c := auxIntToFloat64(v_0.AuxInt)
+		if !(c >= -1<<31 && c < 1<<31) {
+			break
+		}
 		v.reset(OpConst32)
 		v.AuxInt = int32ToAuxInt(int32(c))
 		return true
@@ -6732,12 +6744,16 @@ func rewriteValuegeneric_OpCvt64Fto32F(v *Value) bool {
 func rewriteValuegeneric_OpCvt64Fto64(v *Value) bool {
 	v_0 := v.Args[0]
 	// match: (Cvt64Fto64 (Const64F [c]))
+	// cond: c >= -1<<63 && c < 1<<63
 	// result: (Const64 [int64(c)])
 	for {
 		if v_0.Op != OpConst64F {
 			break
 		}
 		c := auxIntToFloat64(v_0.AuxInt)
+		if !(c >= -1<<63 && c < 1<<63) {
+			break
+		}
 		v.reset(OpConst64)
 		v.AuxInt = int64ToAuxInt(int64(c))
 		return true
diff --git a/test/codegen/math.go b/test/codegen/math.go
index eadf9d7d0554db..5787657d2bc3df 100644
--- a/test/codegen/math.go
+++ b/test/codegen/math.go
@@ -330,3 +330,48 @@ func nanGenerate32() float32 {
 	// amd64/v3:"VFMADD231SS"
 	return z0 + z1
 }
+
+func outOfBoundsConv(i32 *[2]int32, u32 *[2]uint32, i64 *[2]int64, u64 *[2]uint64) {
+	// arm64: "FCVTZSDW"
+	// amd64: "CVTTSD2SL", "CVTSD2SS"
+	i32[0] = int32(two40())
+	// arm64: "FCVTZSDW"
+	// amd64: "CVTTSD2SL", "CVTSD2SS"
+	i32[1] = int32(-two40())
+	// arm64: "FCVTZSDW"
+	// amd64: "CVTTSD2SL", "CVTSD2SS"
+	u32[0] = uint32(two41())
+	// on arm64, this uses an explicit <0 comparison, so it constant folds.
+	// on amd64, this uses an explicit <0 comparison, so it constant folds.
+	// amd64: "MOVL\t[$]0,"
+	u32[1] = uint32(minus1())
+	// arm64: "FCVTZSD"
+	// amd64: "CVTTSD2SQ"
+	i64[0] = int64(two80())
+	// arm64: "FCVTZSD"
+	// amd64: "CVTTSD2SQ"
+	i64[1] = int64(-two80())
+	// arm64: "FCVTZUD"
+	// amd64: "CVTTSD2SQ"
+	u64[0] = uint64(two81())
+	// arm64: "FCVTZUD"
+	// on amd64, this uses an explicit <0 comparison, so it constant folds.
+	// amd64: "MOVQ\t[$]0,"
+	u64[1] = uint64(minus1())
+}
+
+func two40() float64 {
+	return 1 << 40
+}
+func two41() float64 {
+	return 1 << 41
+}
+func two80() float64 {
+	return 1 << 80
+}
+func two81() float64 {
+	return 1 << 81
+}
+func minus1() float64 {
+	return -1
+}

From 9fdd6904da3d6ef2ed457fada1fb26130213f359 Mon Sep 17 00:00:00 2001
From: Russ Cox 
Date: Thu, 9 Oct 2025 15:02:23 -0400
Subject: [PATCH 130/229] strconv: add tests that Java once mishandled

Change-Id: I372233d8494665b3300f9a186c883a4254435e1c
Reviewed-on: https://go-review.googlesource.com/c/go/+/710617
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: David Chase 
---
 src/strconv/ftoa_test.go | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/strconv/ftoa_test.go b/src/strconv/ftoa_test.go
index 3512ccf58070ec..40faa433a64cf8 100644
--- a/src/strconv/ftoa_test.go
+++ b/src/strconv/ftoa_test.go
@@ -172,6 +172,11 @@ var ftoatests = []ftoaTest{
 	{3.999969482421875, 'x', 2, "0x1.00p+02"},
 	{3.999969482421875, 'x', 1, "0x1.0p+02"},
 	{3.999969482421875, 'x', 0, "0x1p+02"},
+
+	// Cases that Java once mishandled, from David Chase.
+	{1.801439850948199e+16, 'g', -1, "1.801439850948199e+16"},
+	{5.960464477539063e-08, 'g', -1, "5.960464477539063e-08"},
+	{1.012e-320, 'g', -1, "1.012e-320"},
 }
 
 func TestFtoa(t *testing.T) {
@@ -186,13 +191,20 @@ func TestFtoa(t *testing.T) {
 			t.Error("AppendFloat testN=64", test.f, string(test.fmt), test.prec, "want", "abc"+test.s, "got", string(x))
 		}
 		if float64(float32(test.f)) == test.f && test.fmt != 'b' {
+			test_s := test.s
+			if test.f == 5.960464477539063e-08 {
+				// This test is an exact float32 but asking for float64 precision in the string.
+				// (All our other float64-only tests fail to exactness check above.)
+				test_s = "5.9604645e-08"
+				continue
+			}
 			s := FormatFloat(test.f, test.fmt, test.prec, 32)
 			if s != test.s {
-				t.Error("testN=32", test.f, string(test.fmt), test.prec, "want", test.s, "got", s)
+				t.Error("testN=32", test.f, string(test.fmt), test.prec, "want", test_s, "got", s)
 			}
 			x := AppendFloat([]byte("abc"), test.f, test.fmt, test.prec, 32)
-			if string(x) != "abc"+test.s {
-				t.Error("AppendFloat testN=32", test.f, string(test.fmt), test.prec, "want", "abc"+test.s, "got", string(x))
+			if string(x) != "abc"+test_s {
+				t.Error("AppendFloat testN=32", test.f, string(test.fmt), test.prec, "want", "abc"+test_s, "got", string(x))
 			}
 		}
 	}

From 1abc6b0204ed231311c9bbc53cfab36dc546aa8e Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Mon, 13 Oct 2025 12:47:42 -0700
Subject: [PATCH 131/229] go/types, types2: permit type cycles through type
 parameter lists

Issue #49439 was about a deadlock during type inference inside
a type parameter list of a recursive constraint. As a remedy
we disallowed recursive type parameter lists.

In the meantime we have removed support for type inference for
type arguments to generic types; the Go 1.18 generic release
didn't support it.

As a consequence, the fix for #49439, CL 361922, is probably
not needed anymore: cycles through type parameter lists are ok.

Fixes #68162.
For #49439.

Change-Id: Ie9deb3274914d428e8e45071cee5e68abf8afe9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/711420
Commit-Queue: Robert Griesemer 
Auto-Submit: Robert Griesemer 
Reviewed-by: Mark Freeman 
Reviewed-by: Robert Griesemer 
TryBot-Bypass: Robert Griesemer 
---
 src/cmd/compile/internal/types2/decl.go       |  6 +++++
 src/go/types/decl.go                          |  6 +++++
 .../types/testdata/fixedbugs/issue45550.go    |  2 +-
 .../types/testdata/fixedbugs/issue46461.go    |  6 ++---
 .../types/testdata/fixedbugs/issue46461a.go   |  7 +++---
 .../types/testdata/fixedbugs/issue47796.go    | 14 +++++------
 .../types/testdata/fixedbugs/issue48529.go    |  2 +-
 .../types/testdata/fixedbugs/issue49439.go    | 14 +++++------
 .../types/testdata/fixedbugs/issue68162.go    | 24 +++++++++++++++++++
 test/typeparam/issue46461.go                  |  4 ++--
 test/typeparam/issue46461b.dir/a.go           |  2 +-
 test/typeparam/issue46461b.dir/b.go           |  4 +---
 test/typeparam/issue48280.dir/a.go            |  2 +-
 test/typeparam/issue48306.dir/a.go            |  2 +-
 14 files changed, 64 insertions(+), 31 deletions(-)
 create mode 100644 src/internal/types/testdata/fixedbugs/issue68162.go

diff --git a/src/cmd/compile/internal/types2/decl.go b/src/cmd/compile/internal/types2/decl.go
index 34105816a65af3..3ff24269669a94 100644
--- a/src/cmd/compile/internal/types2/decl.go
+++ b/src/cmd/compile/internal/types2/decl.go
@@ -302,6 +302,12 @@ loop:
 		}
 	}
 
+	// Cycles through type parameter lists are ok (go.dev/issue/68162).
+	// TODO(gri) if we are happy with this this, remove this flag and simplify code.
+	if tparCycle {
+		return true
+	}
+
 	check.cycleError(cycle, firstInSrc(cycle))
 	return false
 }
diff --git a/src/go/types/decl.go b/src/go/types/decl.go
index 42423d291cee8d..fcae1f95295a67 100644
--- a/src/go/types/decl.go
+++ b/src/go/types/decl.go
@@ -303,6 +303,12 @@ loop:
 		}
 	}
 
+	// Cycles through type parameter lists are ok (go.dev/issue/68162).
+	// TODO(gri) if we are happy with this this, remove this flag and simplify code.
+	if tparCycle {
+		return true
+	}
+
 	check.cycleError(cycle, firstInSrc(cycle))
 	return false
 }
diff --git a/src/internal/types/testdata/fixedbugs/issue45550.go b/src/internal/types/testdata/fixedbugs/issue45550.go
index 2ea4ffe3079540..32fdde6740c7a5 100644
--- a/src/internal/types/testdata/fixedbugs/issue45550.go
+++ b/src/internal/types/testdata/fixedbugs/issue45550.go
@@ -4,7 +4,7 @@
 
 package p
 
-type Builder /* ERROR "invalid recursive type" */ [T interface{ struct{ Builder[T] } }] struct{}
+type Builder[T ~struct{ Builder[T] }] struct{}
 type myBuilder struct {
 	Builder[myBuilder]
 }
diff --git a/src/internal/types/testdata/fixedbugs/issue46461.go b/src/internal/types/testdata/fixedbugs/issue46461.go
index e823013f995167..454f7e836537c6 100644
--- a/src/internal/types/testdata/fixedbugs/issue46461.go
+++ b/src/internal/types/testdata/fixedbugs/issue46461.go
@@ -7,16 +7,16 @@
 package p
 
 // test case 1
-type T /* ERROR "invalid recursive type" */ [U interface{ M() T[U] }] int
+type T[U interface{ M() T[U] }] int
 
 type X int
 
 func (X) M() T[X] { return 0 }
 
 // test case 2
-type A /* ERROR "invalid recursive type" */ [T interface{ A[T] }] interface{}
+type A[T interface{ A[T] }] interface{}
 
 // test case 3
-type A2 /* ERROR "invalid recursive type" */ [U interface{ A2[U] }] interface{ M() A2[U] }
+type A2[U interface{ A2[U] }] interface{ M() A2[U] }
 
 type I interface{ A2[I]; M() A2[I] }
diff --git a/src/internal/types/testdata/fixedbugs/issue46461a.go b/src/internal/types/testdata/fixedbugs/issue46461a.go
index e4b8e1a240a973..74ed6c4882719c 100644
--- a/src/internal/types/testdata/fixedbugs/issue46461a.go
+++ b/src/internal/types/testdata/fixedbugs/issue46461a.go
@@ -7,17 +7,16 @@
 package p
 
 // test case 1
-type T /* ERROR "invalid recursive type" */ [U interface{ M() T[U] }] int
+type T[U interface{ M() T[U] }] int
 
 type X int
 
 func (X) M() T[X] { return 0 }
 
 // test case 2
-type A /* ERROR "invalid recursive type" */ [T interface{ A[T] }] interface{}
+type A[T interface{ A[T] }] interface{}
 
 // test case 3
-// TODO(gri) should report error only once
-type A2 /* ERROR "invalid recursive type" */ /* ERROR "invalid recursive type" */ [U interface{ A2[U] }] interface{ M() A2[U] }
+type A2[U interface{ A2[U] }] interface{ M() A2[U] }
 
 type I interface{ A2[I]; M() A2[I] }
diff --git a/src/internal/types/testdata/fixedbugs/issue47796.go b/src/internal/types/testdata/fixedbugs/issue47796.go
index 7f719ff6745eaa..b07cdddababf67 100644
--- a/src/internal/types/testdata/fixedbugs/issue47796.go
+++ b/src/internal/types/testdata/fixedbugs/issue47796.go
@@ -6,16 +6,16 @@ package p
 
 // parameterized types with self-recursive constraints
 type (
-	T1 /* ERROR "invalid recursive type" */ [P T1[P]]                            interface{}
-	T2 /* ERROR "invalid recursive type" */ [P, Q T2[P, Q]]                      interface{}
+	T1[P T1[P]]                            interface{}
+	T2[P, Q T2[P, Q]]                      interface{}
 	T3[P T2[P, Q], Q interface{ ~string }] interface{}
 
-	T4a /* ERROR "invalid recursive type" */ [P T4a[P]]                                                        interface{ ~int }
-	T4b /* ERROR "invalid recursive type" */ [P T4b[int]]                                                      interface{ ~int }
-	T4c /* ERROR "invalid recursive type" */ [P T4c[string]] interface{ ~int }
+	T4a[P T4a[P]]                                                        interface{ ~int }
+	T4b[P T4b[int]]                                                      interface{ ~int }
+	T4c[P T4c[string /* ERROR "string does not satisfy T4c[string]" */]] interface{ ~int }
 
 	// mutually recursive constraints
-	T5 /* ERROR "invalid recursive type" */ [P T6[P]] interface{ int }
+	T5[P T6[P]] interface{ int }
 	T6[P T5[P]] interface{ int }
 )
 
@@ -28,6 +28,6 @@ var (
 
 // test case from issue
 
-type Eq /* ERROR "invalid recursive type" */ [a Eq[a]] interface {
+type Eq[a Eq[a]] interface {
 	Equal(that a) bool
 }
diff --git a/src/internal/types/testdata/fixedbugs/issue48529.go b/src/internal/types/testdata/fixedbugs/issue48529.go
index bcc5e3536d3457..eca1da89232b08 100644
--- a/src/internal/types/testdata/fixedbugs/issue48529.go
+++ b/src/internal/types/testdata/fixedbugs/issue48529.go
@@ -4,7 +4,7 @@
 
 package p
 
-type T /* ERROR "invalid recursive type" */ [U interface{ M() T[U, int] }] int
+type T[U interface{ M() T /* ERROR "too many type arguments for type T" */ [U, int] }] int
 
 type X int
 
diff --git a/src/internal/types/testdata/fixedbugs/issue49439.go b/src/internal/types/testdata/fixedbugs/issue49439.go
index 3852f160948913..63bedf61911914 100644
--- a/src/internal/types/testdata/fixedbugs/issue49439.go
+++ b/src/internal/types/testdata/fixedbugs/issue49439.go
@@ -6,21 +6,21 @@ package p
 
 import "unsafe"
 
-type T0 /* ERROR "invalid recursive type" */ [P T0[P]] struct{}
+type T0[P T0[P]] struct{}
 
-type T1 /* ERROR "invalid recursive type" */ [P T2[P]] struct{}
-type T2[P T1[P]] struct{}
+type T1[P T2[P /* ERROR "P does not satisfy T1[P]" */]] struct{}
+type T2[P T1[P /* ERROR "P does not satisfy T2[P]" */]] struct{}
 
-type T3 /* ERROR "invalid recursive type" */ [P interface{ ~struct{ f T3[int] } }] struct{}
+type T3[P interface{ ~struct{ f T3[int /* ERROR "int does not satisfy" */ ] } }] struct{}
 
 // valid cycle in M
 type N[P M[P]] struct{}
-type M[Q any] struct { F *M[Q] }
+type M[Q any] struct{ F *M[Q] }
 
 // "crazy" case
 type TC[P [unsafe.Sizeof(func() {
-        type T [P [unsafe.Sizeof(func(){})]byte] struct{}
+	type T[P [unsafe.Sizeof(func() {})]byte] struct{}
 })]byte] struct{}
 
 // test case from issue
-type X /* ERROR "invalid recursive type" */ [T any, PT X[T]] interface{}
+type X[T any, PT X /* ERROR "not enough type arguments for type X" */ [T]] interface{}
diff --git a/src/internal/types/testdata/fixedbugs/issue68162.go b/src/internal/types/testdata/fixedbugs/issue68162.go
new file mode 100644
index 00000000000000..8efd8a66dff4be
--- /dev/null
+++ b/src/internal/types/testdata/fixedbugs/issue68162.go
@@ -0,0 +1,24 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+type N[B N[B]] interface {
+	Add(B) B
+}
+
+func Add[P N[P]](x, y P) P {
+	return x.Add(y)
+}
+
+type MyInt int
+
+func (x MyInt) Add(y MyInt) MyInt {
+	return x + y
+}
+
+func main() {
+	var x, y MyInt = 2, 3
+	println(Add(x, y))
+}
diff --git a/test/typeparam/issue46461.go b/test/typeparam/issue46461.go
index 363a87cfe08f10..7e35106c15b42e 100644
--- a/test/typeparam/issue46461.go
+++ b/test/typeparam/issue46461.go
@@ -1,4 +1,4 @@
-// errorcheck
+// compile
 
 // Copyright 2021 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -6,7 +6,7 @@
 
 package p
 
-type T[U interface{ M() T[U] }] int // ERROR "invalid recursive type: T refers to itself"
+type T[U interface{ M() T[U] }] int
 
 type X int
 
diff --git a/test/typeparam/issue46461b.dir/a.go b/test/typeparam/issue46461b.dir/a.go
index fcb414266d741c..0d53b3e20429cd 100644
--- a/test/typeparam/issue46461b.dir/a.go
+++ b/test/typeparam/issue46461b.dir/a.go
@@ -4,4 +4,4 @@
 
 package a
 
-type T[U interface{ M() int }] int
+type T[U interface{ M() T[U] }] int
diff --git a/test/typeparam/issue46461b.dir/b.go b/test/typeparam/issue46461b.dir/b.go
index a4583257ffd657..3393a375c20570 100644
--- a/test/typeparam/issue46461b.dir/b.go
+++ b/test/typeparam/issue46461b.dir/b.go
@@ -8,6 +8,4 @@ import "./a"
 
 type X int
 
-func (X) M() int { return 0 }
-
-type _ a.T[X]
+func (X) M() a.T[X] { return 0 }
diff --git a/test/typeparam/issue48280.dir/a.go b/test/typeparam/issue48280.dir/a.go
index f66fd30e34ee43..17859e6aa902f0 100644
--- a/test/typeparam/issue48280.dir/a.go
+++ b/test/typeparam/issue48280.dir/a.go
@@ -4,7 +4,7 @@
 
 package a
 
-type I[T any] interface {
+type I[T I[T]] interface {
 	F() T
 }
 
diff --git a/test/typeparam/issue48306.dir/a.go b/test/typeparam/issue48306.dir/a.go
index fdfd86cb6d4a5d..739750b20b35e6 100644
--- a/test/typeparam/issue48306.dir/a.go
+++ b/test/typeparam/issue48306.dir/a.go
@@ -4,6 +4,6 @@
 
 package a
 
-type I[T any] interface {
+type I[T I[T]] interface {
 	F() T
 }

From 6fd8e88d07b08531a5585aa4fbcc6043d556742f Mon Sep 17 00:00:00 2001
From: Joe Tsai 
Date: Sat, 11 Oct 2025 11:37:58 -0700
Subject: [PATCH 132/229] encoding/json/v2: restrict presence of default
 options

Originally, DefaultOptionsV1 and DefaultOptionsV2 represented
the full set of all options with specific ones set to true or false.

However, there are certain options such as WithIndent or WithMarshalers
that are neither v1 or v2 specific.
At some point we removed whitespace related options from the set:
https://github.com/go-json-experiment/json/pull/26

This avoids DefaultOptionsV1 or DefaultOptionsV2 from affecting
any previously set whitespace. However, why are whitespace options
special and thus excluded from the set? What about Marshalers?

As a more principaled way to address this, we restrict
DefaultOptionsV1 and DefaultOptionsV2 to only be the options
where the default setting changes between v1 and v2.
All other options are unpopulated.

This avoids a panic with GetOption(DefaultOptionsV2, WithMarshalers)
since DefaultOptionsV2 previously had the presence bit for
Marshalers set to true, but had no actual value.
Now, the presence bit is set to false, so the value is not consulted.

Fixes #75149

Change-Id: I30b45abd35404578b4135cc3bad1a1a2993cb0cf
Reviewed-on: https://go-review.googlesource.com/c/go/+/710878
Reviewed-by: Johan Brandhorst-Satzkorn 
Reviewed-by: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Damien Neil 
---
 src/encoding/json/internal/jsonopts/options.go      | 8 ++++----
 src/encoding/json/internal/jsonopts/options_test.go | 3 +++
 src/encoding/json/v2/options.go                     | 5 ++---
 src/encoding/json/v2_options.go                     | 4 +---
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/encoding/json/internal/jsonopts/options.go b/src/encoding/json/internal/jsonopts/options.go
index e4c3f47d36adc8..39da81b34549ec 100644
--- a/src/encoding/json/internal/jsonopts/options.go
+++ b/src/encoding/json/internal/jsonopts/options.go
@@ -48,16 +48,16 @@ type ArshalValues struct {
 // DefaultOptionsV2 is the set of all options that define default v2 behavior.
 var DefaultOptionsV2 = Struct{
 	Flags: jsonflags.Flags{
-		Presence: uint64(jsonflags.AllFlags & ^jsonflags.WhitespaceFlags),
-		Values:   uint64(0),
+		Presence: uint64(jsonflags.DefaultV1Flags),
+		Values:   uint64(0), // all flags in DefaultV1Flags are false
 	},
 }
 
 // DefaultOptionsV1 is the set of all options that define default v1 behavior.
 var DefaultOptionsV1 = Struct{
 	Flags: jsonflags.Flags{
-		Presence: uint64(jsonflags.AllFlags & ^jsonflags.WhitespaceFlags),
-		Values:   uint64(jsonflags.DefaultV1Flags),
+		Presence: uint64(jsonflags.DefaultV1Flags),
+		Values:   uint64(jsonflags.DefaultV1Flags), // all flags in DefaultV1Flags are true
 	},
 }
 
diff --git a/src/encoding/json/internal/jsonopts/options_test.go b/src/encoding/json/internal/jsonopts/options_test.go
index ebfaf05c833e05..caa686e4f0d579 100644
--- a/src/encoding/json/internal/jsonopts/options_test.go
+++ b/src/encoding/json/internal/jsonopts/options_test.go
@@ -200,6 +200,9 @@ func TestGet(t *testing.T) {
 	if v, ok := json.GetOption(opts, json.WithUnmarshalers); v != nil || ok {
 		t.Errorf(`GetOption(..., WithUnmarshalers) = (%v, %v), want (nil, false)`, v, ok)
 	}
+	if v, ok := json.GetOption(json.DefaultOptionsV2(), json.WithMarshalers); v != nil || ok {
+		t.Errorf(`GetOption(..., WithMarshalers) = (%v, %v), want (nil, false)`, v, ok)
+	}
 }
 
 var sink struct {
diff --git a/src/encoding/json/v2/options.go b/src/encoding/json/v2/options.go
index 0942d2d30784f9..9685f20f9f805f 100644
--- a/src/encoding/json/v2/options.go
+++ b/src/encoding/json/v2/options.go
@@ -97,9 +97,8 @@ func GetOption[T any](opts Options, setter func(T) Options) (T, bool) {
 }
 
 // DefaultOptionsV2 is the full set of all options that define v2 semantics.
-// It is equivalent to all options under [Options], [encoding/json.Options],
-// and [encoding/json/jsontext.Options] being set to false or the zero value,
-// except for the options related to whitespace formatting.
+// It is equivalent to the set of options in [encoding/json.DefaultOptionsV1]
+// all being set to false. All other options are not present.
 func DefaultOptionsV2() Options {
 	return &jsonopts.DefaultOptionsV2
 }
diff --git a/src/encoding/json/v2_options.go b/src/encoding/json/v2_options.go
index 819fe59f412c68..2bdec86fdeab5b 100644
--- a/src/encoding/json/v2_options.go
+++ b/src/encoding/json/v2_options.go
@@ -227,9 +227,7 @@ type Options = jsonopts.Options
 //   - [jsontext.EscapeForJS]
 //   - [jsontext.PreserveRawStrings]
 //
-// All other boolean options are set to false.
-// All non-boolean options are set to the zero value,
-// except for [jsontext.WithIndent], which defaults to "\t".
+// All other options are not present.
 //
 // The [Marshal] and [Unmarshal] functions in this package are
 // semantically identical to calling the v2 equivalents with this option:

From 60f6d2f6230c5085ad25a9e3ebdaaae2aefdfe36 Mon Sep 17 00:00:00 2001
From: Filippo Valsorda 
Date: Wed, 8 Oct 2025 13:02:36 +0200
Subject: [PATCH 133/229] crypto/internal/fips140/entropy: support SHA-384
 sizes for ACVP tests
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Change-Id: I6a6a6964decc662d753ee3eec357570bd3c95e2d
Reviewed-on: https://go-review.googlesource.com/c/go/+/710056
Auto-Submit: Filippo Valsorda 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Roland Shoemaker 
Reviewed-by: Nooras Saba‎ 
Reviewed-by: Daniel McCarney 
---
 src/crypto/internal/fips140/entropy/sha384.go | 57 +++++++++++++++----
 .../internal/fips140test/entropy_test.go      | 13 ++++-
 2 files changed, 58 insertions(+), 12 deletions(-)

diff --git a/src/crypto/internal/fips140/entropy/sha384.go b/src/crypto/internal/fips140/entropy/sha384.go
index ec23cfc9ad3661..c20f76b57979af 100644
--- a/src/crypto/internal/fips140/entropy/sha384.go
+++ b/src/crypto/internal/fips140/entropy/sha384.go
@@ -8,19 +8,22 @@ import "math/bits"
 
 // This file includes a SHA-384 implementation to insulate the entropy source
 // from any changes in the FIPS 140-3 module's crypto/internal/fips140/sha512
-// package. We only support 1024-byte inputs.
+// package. We support 1024-byte inputs for the entropy source, and arbitrary
+// length inputs for ACVP testing.
+
+var initState = [8]uint64{
+	0xcbbb9d5dc1059ed8,
+	0x629a292a367cd507,
+	0x9159015a3070dd17,
+	0x152fecd8f70e5939,
+	0x67332667ffc00b31,
+	0x8eb44a8768581511,
+	0xdb0c2e0d64f98fa7,
+	0x47b5481dbefa4fa4,
+}
 
 func SHA384(p *[1024]byte) [48]byte {
-	h := [8]uint64{
-		0xcbbb9d5dc1059ed8,
-		0x629a292a367cd507,
-		0x9159015a3070dd17,
-		0x152fecd8f70e5939,
-		0x67332667ffc00b31,
-		0x8eb44a8768581511,
-		0xdb0c2e0d64f98fa7,
-		0x47b5481dbefa4fa4,
-	}
+	h := initState
 
 	sha384Block(&h, (*[128]byte)(p[0:128]))
 	sha384Block(&h, (*[128]byte)(p[128:256]))
@@ -36,6 +39,38 @@ func SHA384(p *[1024]byte) [48]byte {
 	bePutUint64(padlen[112+8:], 1024*8)
 	sha384Block(&h, &padlen)
 
+	return digestBytes(&h)
+}
+
+func TestingOnlySHA384(p []byte) [48]byte {
+	if len(p) == 1024 {
+		return SHA384((*[1024]byte)(p))
+	}
+
+	h := initState
+	bitLen := uint64(len(p)) * 8
+
+	// Process full 128-byte blocks.
+	for len(p) >= 128 {
+		sha384Block(&h, (*[128]byte)(p[:128]))
+		p = p[128:]
+	}
+
+	// Process final block and padding.
+	var finalBlock [128]byte
+	copy(finalBlock[:], p)
+	finalBlock[len(p)] = 0x80
+	if len(p) >= 112 {
+		sha384Block(&h, &finalBlock)
+		finalBlock = [128]byte{}
+	}
+	bePutUint64(finalBlock[112+8:], bitLen)
+	sha384Block(&h, &finalBlock)
+
+	return digestBytes(&h)
+}
+
+func digestBytes(h *[8]uint64) [48]byte {
 	var digest [48]byte
 	bePutUint64(digest[0:], h[0])
 	bePutUint64(digest[8:], h[1])
diff --git a/src/crypto/internal/fips140test/entropy_test.go b/src/crypto/internal/fips140test/entropy_test.go
index a84b50c62b22b6..ef6909efbac2f6 100644
--- a/src/crypto/internal/fips140test/entropy_test.go
+++ b/src/crypto/internal/fips140test/entropy_test.go
@@ -11,6 +11,7 @@ import (
 	"crypto/internal/cryptotest"
 	"crypto/internal/fips140/drbg"
 	"crypto/internal/fips140/entropy"
+	"crypto/rand"
 	"crypto/sha256"
 	"crypto/sha512"
 	"encoding/hex"
@@ -159,6 +160,16 @@ func TestEntropySHA384(t *testing.T) {
 	if got != want {
 		t.Errorf("SHA384() = %x, want %x", got, want)
 	}
+
+	for l := range 1024*3 + 1 {
+		input := make([]byte, l)
+		rand.Read(input)
+		want := sha512.Sum384(input)
+		got := entropy.TestingOnlySHA384(input)
+		if got != want {
+			t.Errorf("TestingOnlySHA384(%d bytes) = %x, want %x", l, got, want)
+		}
+	}
 }
 
 func TestEntropyRepetitionCountTest(t *testing.T) {
@@ -230,7 +241,7 @@ func TestEntropyUnchanged(t *testing.T) {
 	// entropy source through the Entropy Source Validation program,
 	// independently of the FIPS 140-3 module. It must not change even across
 	// FIPS 140-3 module versions, in order to reuse the ESV certificate.
-	exp := "35976eb8a11678c79777da07aaab5511d4325701f837777df205f6e7b20c6821"
+	exp := "1b68d4c091ef66c6006602e4ed3ac10f8a82ad193708ec99d63b145e3baa3e6c"
 	if got := hex.EncodeToString(h.Sum(nil)); got != exp {
 		t.Errorf("hash of crypto/internal/fips140/entropy = %s, want %s", got, exp)
 	}

From f6b9d56affb75103507f2b6ed4ffa98ca899b39d Mon Sep 17 00:00:00 2001
From: Filippo Valsorda 
Date: Wed, 8 Oct 2025 13:30:34 +0200
Subject: [PATCH 134/229] crypto/internal/fips140/entropy: fix benign race

Fixes #75690
Fixes #75842

Change-Id: I6a6a696420f51f28f48535c34cf347e2cbd4add5
Reviewed-on: https://go-review.googlesource.com/c/go/+/710058
Auto-Submit: Filippo Valsorda 
Reviewed-by: David Chase 
Reviewed-by: Roland Shoemaker 
LUCI-TryBot-Result: Go LUCI 
---
 src/crypto/internal/fips140/entropy/entropy.go  | 4 +++-
 src/crypto/internal/fips140test/entropy_test.go | 6 +++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/crypto/internal/fips140/entropy/entropy.go b/src/crypto/internal/fips140/entropy/entropy.go
index 273f05c817aff8..f5b2f53752a028 100644
--- a/src/crypto/internal/fips140/entropy/entropy.go
+++ b/src/crypto/internal/fips140/entropy/entropy.go
@@ -123,7 +123,9 @@ func (s *source) Sample() uint8 {
 	// Perform a few memory accesses in an unpredictable pattern to expose the
 	// next measurement to as much system noise as possible.
 	memory, lcgState := s.memory, s.lcgState
-	_ = memory[0] // hoist the nil check out of touchMemory
+	if memory == nil { // remove the nil check from the inlined touchMemory calls
+		panic("entropy: nil memory buffer")
+	}
 	for range 64 {
 		lcgState = 1664525*lcgState + 1013904223
 		// Discard the lower bits, which tend to fall into short cycles.
diff --git a/src/crypto/internal/fips140test/entropy_test.go b/src/crypto/internal/fips140test/entropy_test.go
index ef6909efbac2f6..a33e2e7bbc907d 100644
--- a/src/crypto/internal/fips140test/entropy_test.go
+++ b/src/crypto/internal/fips140test/entropy_test.go
@@ -241,7 +241,7 @@ func TestEntropyUnchanged(t *testing.T) {
 	// entropy source through the Entropy Source Validation program,
 	// independently of the FIPS 140-3 module. It must not change even across
 	// FIPS 140-3 module versions, in order to reuse the ESV certificate.
-	exp := "1b68d4c091ef66c6006602e4ed3ac10f8a82ad193708ec99d63b145e3baa3e6c"
+	exp := "2541273241ae8aafe55026328354ed3799df1e2fb308b2097833203a42911b53"
 	if got := hex.EncodeToString(h.Sum(nil)); got != exp {
 		t.Errorf("hash of crypto/internal/fips140/entropy = %s, want %s", got, exp)
 	}
@@ -249,12 +249,12 @@ func TestEntropyUnchanged(t *testing.T) {
 
 func TestEntropyRace(t *testing.T) {
 	// Check that concurrent calls to Seed don't trigger the race detector.
-	for range 2 {
+	for range 16 {
 		go func() {
 			_, _ = entropy.Seed(&memory)
 		}()
 	}
-	// Same, with the higher-level DRBG. More concurrent calls to hit the Pool.
+	// Same, with the higher-level DRBG.
 	for range 16 {
 		go func() {
 			var b [64]byte

From 3765758b96746e202bb52312d4b026085a0f25a1 Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Mon, 13 Oct 2025 15:55:04 -0700
Subject: [PATCH 135/229] go/types, types2: minor cleanup (remove TODO)

Follow-up to CL 711420.

Change-Id: If577e96f413e46b98dd86d11605de1004637851a
Reviewed-on: https://go-review.googlesource.com/c/go/+/711540
Reviewed-by: Robert Griesemer 
Reviewed-by: Mark Freeman 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/compile/internal/types2/decl.go | 35 +++++++++++--------------
 src/go/types/decl.go                    | 35 +++++++++++--------------
 2 files changed, 32 insertions(+), 38 deletions(-)

diff --git a/src/cmd/compile/internal/types2/decl.go b/src/cmd/compile/internal/types2/decl.go
index 3ff24269669a94..4ebd9454070757 100644
--- a/src/cmd/compile/internal/types2/decl.go
+++ b/src/cmd/compile/internal/types2/decl.go
@@ -225,8 +225,8 @@ func (check *Checker) validCycle(obj Object) (valid bool) {
 	start := obj.color() - grey // index of obj in objPath
 	cycle := check.objPath[start:]
 	tparCycle := false // if set, the cycle is through a type parameter list
-	nval := 0          // number of (constant or variable) values in the cycle; valid if !generic
-	ndef := 0          // number of type definitions in the cycle; valid if !generic
+	nval := 0          // number of (constant or variable) values in the cycle
+	ndef := 0          // number of type definitions in the cycle
 loop:
 	for _, obj := range cycle {
 		switch obj := obj.(type) {
@@ -235,7 +235,7 @@ loop:
 		case *TypeName:
 			// If we reach a generic type that is part of a cycle
 			// and we are in a type parameter list, we have a cycle
-			// through a type parameter list, which is invalid.
+			// through a type parameter list.
 			if check.inTParamList && isGeneric(obj.typ) {
 				tparCycle = true
 				break loop
@@ -286,25 +286,22 @@ loop:
 		}()
 	}
 
-	if !tparCycle {
-		// A cycle involving only constants and variables is invalid but we
-		// ignore them here because they are reported via the initialization
-		// cycle check.
-		if nval == len(cycle) {
-			return true
-		}
+	// Cycles through type parameter lists are ok (go.dev/issue/68162).
+	if tparCycle {
+		return true
+	}
 
-		// A cycle involving only types (and possibly functions) must have at least
-		// one type definition to be permitted: If there is no type definition, we
-		// have a sequence of alias type names which will expand ad infinitum.
-		if nval == 0 && ndef > 0 {
-			return true
-		}
+	// A cycle involving only constants and variables is invalid but we
+	// ignore them here because they are reported via the initialization
+	// cycle check.
+	if nval == len(cycle) {
+		return true
 	}
 
-	// Cycles through type parameter lists are ok (go.dev/issue/68162).
-	// TODO(gri) if we are happy with this this, remove this flag and simplify code.
-	if tparCycle {
+	// A cycle involving only types (and possibly functions) must have at least
+	// one type definition to be permitted: If there is no type definition, we
+	// have a sequence of alias type names which will expand ad infinitum.
+	if nval == 0 && ndef > 0 {
 		return true
 	}
 
diff --git a/src/go/types/decl.go b/src/go/types/decl.go
index fcae1f95295a67..aef7f6ad0b9099 100644
--- a/src/go/types/decl.go
+++ b/src/go/types/decl.go
@@ -226,8 +226,8 @@ func (check *Checker) validCycle(obj Object) (valid bool) {
 	start := obj.color() - grey // index of obj in objPath
 	cycle := check.objPath[start:]
 	tparCycle := false // if set, the cycle is through a type parameter list
-	nval := 0          // number of (constant or variable) values in the cycle; valid if !generic
-	ndef := 0          // number of type definitions in the cycle; valid if !generic
+	nval := 0          // number of (constant or variable) values in the cycle
+	ndef := 0          // number of type definitions in the cycle
 loop:
 	for _, obj := range cycle {
 		switch obj := obj.(type) {
@@ -236,7 +236,7 @@ loop:
 		case *TypeName:
 			// If we reach a generic type that is part of a cycle
 			// and we are in a type parameter list, we have a cycle
-			// through a type parameter list, which is invalid.
+			// through a type parameter list.
 			if check.inTParamList && isGeneric(obj.typ) {
 				tparCycle = true
 				break loop
@@ -287,25 +287,22 @@ loop:
 		}()
 	}
 
-	if !tparCycle {
-		// A cycle involving only constants and variables is invalid but we
-		// ignore them here because they are reported via the initialization
-		// cycle check.
-		if nval == len(cycle) {
-			return true
-		}
+	// Cycles through type parameter lists are ok (go.dev/issue/68162).
+	if tparCycle {
+		return true
+	}
 
-		// A cycle involving only types (and possibly functions) must have at least
-		// one type definition to be permitted: If there is no type definition, we
-		// have a sequence of alias type names which will expand ad infinitum.
-		if nval == 0 && ndef > 0 {
-			return true
-		}
+	// A cycle involving only constants and variables is invalid but we
+	// ignore them here because they are reported via the initialization
+	// cycle check.
+	if nval == len(cycle) {
+		return true
 	}
 
-	// Cycles through type parameter lists are ok (go.dev/issue/68162).
-	// TODO(gri) if we are happy with this this, remove this flag and simplify code.
-	if tparCycle {
+	// A cycle involving only types (and possibly functions) must have at least
+	// one type definition to be permitted: If there is no type definition, we
+	// have a sequence of alias type names which will expand ad infinitum.
+	if nval == 0 && ndef > 0 {
 		return true
 	}
 

From 5a9ef44bc05b937cff2394b5880ecca616cb878e Mon Sep 17 00:00:00 2001
From: Mateusz Poliwczak 
Date: Sun, 12 Oct 2025 11:15:11 +0200
Subject: [PATCH 136/229] cmd/compile/internal/devirtualize: fix OCONVNOP
 assertion

Fixes #75863

Change-Id: I1e5a0f3880dcd5f820a5b6f4540c49b16a6a6964
Reviewed-on: https://go-review.googlesource.com/c/go/+/711141
Reviewed-by: Keith Randall 
Reviewed-by: Lasse Folger 
Auto-Submit: Keith Randall 
Reviewed-by: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/compile/internal/devirtualize/devirtualize.go | 2 +-
 test/devirtualization.go                              | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/cmd/compile/internal/devirtualize/devirtualize.go b/src/cmd/compile/internal/devirtualize/devirtualize.go
index 9d4160085edde9..363cd6f2e5d17a 100644
--- a/src/cmd/compile/internal/devirtualize/devirtualize.go
+++ b/src/cmd/compile/internal/devirtualize/devirtualize.go
@@ -223,7 +223,7 @@ func concreteType1(s *State, n ir.Node, seen map[*ir.Name]struct{}) (outT *types
 		switch n1 := n.(type) {
 		case *ir.ConvExpr:
 			if n1.Op() == ir.OCONVNOP {
-				if !n1.Type().IsInterface() || !types.Identical(n1.Type(), n1.X.Type()) {
+				if !n1.Type().IsInterface() || !types.Identical(n1.Type().Underlying(), n1.X.Type().Underlying()) {
 					// As we check (directly before this switch) whether n is an interface, thus we should only reach
 					// here for iface conversions where both operands are the same.
 					base.Fatalf("not identical/interface types found n1.Type = %v; n1.X.Type = %v", n1.Type(), n1.X.Type())
diff --git a/test/devirtualization.go b/test/devirtualization.go
index e3319052945e00..edabb94108d02d 100644
--- a/test/devirtualization.go
+++ b/test/devirtualization.go
@@ -1139,6 +1139,12 @@ func devirtWrapperType() {
 		var a A = (implWrapper)(i) // ERROR "implWrapper\(i\) does not escape$"
 		a.A()                      // ERROR "devirtualizing a.A to implWrapper$" "inlining call to implWrapper.A"
 	}
+	{
+		type anyWrapper any
+		var foo any = &Impl{} // ERROR "&Impl\{\} does not escape"
+		var bar anyWrapper = foo
+		bar.(M).M() // ERROR "devirtualizing bar\.\(M\).M to \*Impl" "inlining call to \(\*Impl\)\.M"
+	}
 }
 
 func selfAssigns() {

From 0a239bcc9987b8a20a152feceb4884e810683a2c Mon Sep 17 00:00:00 2001
From: Damien Neil 
Date: Tue, 14 Oct 2025 09:34:11 -0700
Subject: [PATCH 137/229] Revert "net/url: disallow raw IPv6 addresses in host"

This reverts commit e3be2d1b2b68d960398a343805f77052d5decb22.

Reason for revert: Causes extensive failures in Google-internal testing.

Change-Id: I232f547fc326dff7df959d25f3a89777ea33b201
Reviewed-on: https://go-review.googlesource.com/c/go/+/711800
Auto-Submit: Damien Neil 
Reviewed-by: Sean Liao 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Pratt 
---
 src/net/url/url.go      |  4 +---
 src/net/url/url_test.go | 23 ++++++++++++++++++++---
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/net/url/url.go b/src/net/url/url.go
index a69754880149a9..6afa30f162bd25 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -698,9 +698,7 @@ func parseHost(host string) (string, error) {
 			return "", errors.New("invalid IP-literal")
 		}
 		return "[" + unescapedHostname + "]" + unescapedColonPort, nil
-	} else if i := strings.Index(host, ":"); i != -1 {
-		// IPv4address / reg-name
-		// E.g. 1.2.3.4, 1.2.3.4:80, example.com, example.com:80
+	} else if i := strings.LastIndex(host, ":"); i != -1 {
 		colonPort := host[i:]
 		if !validOptionalPort(colonPort) {
 			return "", fmt.Errorf("invalid port %q after host", colonPort)
diff --git a/src/net/url/url_test.go b/src/net/url/url_test.go
index a7543d6fd40b1e..6084facacc0519 100644
--- a/src/net/url/url_test.go
+++ b/src/net/url/url_test.go
@@ -506,6 +506,26 @@ var urltests = []URLTest{
 		},
 		"",
 	},
+	{
+		// Malformed IPv6 but still accepted.
+		"http://2b01:e34:ef40:7730:8e70:5aff:fefe:edac:8080/foo",
+		&URL{
+			Scheme: "http",
+			Host:   "2b01:e34:ef40:7730:8e70:5aff:fefe:edac:8080",
+			Path:   "/foo",
+		},
+		"",
+	},
+	{
+		// Malformed IPv6 but still accepted.
+		"http://2b01:e34:ef40:7730:8e70:5aff:fefe:edac:/foo",
+		&URL{
+			Scheme: "http",
+			Host:   "2b01:e34:ef40:7730:8e70:5aff:fefe:edac:",
+			Path:   "/foo",
+		},
+		"",
+	},
 	{
 		"http://[2b01:e34:ef40:7730:8e70:5aff:fefe:edac]:8080/foo",
 		&URL{
@@ -715,9 +735,6 @@ var parseRequestURLTests = []struct {
 	{"https://[0:0::test.com]:80", false},
 	{"https://[2001:db8::test.com]", false},
 	{"https://[test.com]", false},
-	{"https://1:2:3:4:5:6:7:8", false},
-	{"https://1:2:3:4:5:6:7:8:80", false},
-	{"https://example.com:80:", false},
 }
 
 func TestParseRequestURI(t *testing.T) {

From 0ddb5ed4653a2cac6ecc7315fcbb1e9f6dcb6dda Mon Sep 17 00:00:00 2001
From: Mateusz Poliwczak 
Date: Sun, 12 Oct 2025 10:56:13 +0200
Subject: [PATCH 138/229] cmd/compile/internal/devirtualize: use FatalfAt
 instead of Fatalf where possible

Change-Id: I5e9e9c89336446720c3c21347969e4126a6a6964
Reviewed-on: https://go-review.googlesource.com/c/go/+/711140
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Dmitri Shuralyov 
Auto-Submit: Keith Randall 
---
 .../internal/devirtualize/devirtualize.go     | 24 +++++++++----------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/cmd/compile/internal/devirtualize/devirtualize.go b/src/cmd/compile/internal/devirtualize/devirtualize.go
index 363cd6f2e5d17a..dfcdd42236dcca 100644
--- a/src/cmd/compile/internal/devirtualize/devirtualize.go
+++ b/src/cmd/compile/internal/devirtualize/devirtualize.go
@@ -187,7 +187,7 @@ func concreteType(s *State, n ir.Node) (typ *types.Type) {
 		return nil
 	}
 	if typ != nil && typ.IsInterface() {
-		base.Fatalf("typ.IsInterface() = true; want = false; typ = %v", typ)
+		base.FatalfAt(n.Pos(), "typ.IsInterface() = true; want = false; typ = %v", typ)
 	}
 	return typ
 }
@@ -226,7 +226,7 @@ func concreteType1(s *State, n ir.Node, seen map[*ir.Name]struct{}) (outT *types
 				if !n1.Type().IsInterface() || !types.Identical(n1.Type().Underlying(), n1.X.Type().Underlying()) {
 					// As we check (directly before this switch) whether n is an interface, thus we should only reach
 					// here for iface conversions where both operands are the same.
-					base.Fatalf("not identical/interface types found n1.Type = %v; n1.X.Type = %v", n1.Type(), n1.X.Type())
+					base.FatalfAt(n1.Pos(), "not identical/interface types found n1.Type = %v; n1.X.Type = %v", n1.Type(), n1.X.Type())
 				}
 				n = n1.X
 				continue
@@ -260,12 +260,12 @@ func concreteType1(s *State, n ir.Node, seen map[*ir.Name]struct{}) (outT *types
 	}
 
 	if name.Op() != ir.ONAME {
-		base.Fatalf("name.Op = %v; want = ONAME", n.Op())
+		base.FatalfAt(name.Pos(), "name.Op = %v; want = ONAME", n.Op())
 	}
 
 	// name.Curfn must be set, as we checked name.Class != ir.PAUTO before.
 	if name.Curfn == nil {
-		base.Fatalf("name.Curfn = nil; want not nil")
+		base.FatalfAt(name.Pos(), "name.Curfn = nil; want not nil")
 	}
 
 	if name.Addrtaken() {
@@ -385,11 +385,11 @@ func (s *State) InlinedCall(fun *ir.Func, origCall *ir.CallExpr, inlinedCall *ir
 func (s *State) assignments(n *ir.Name) []assignment {
 	fun := n.Curfn
 	if fun == nil {
-		base.Fatalf("n.Curfn = ")
+		base.FatalfAt(n.Pos(), "n.Curfn = ")
 	}
 
 	if !n.Type().IsInterface() {
-		base.Fatalf("name passed to assignments is not of an interface type: %v", n.Type())
+		base.FatalfAt(n.Pos(), "name passed to assignments is not of an interface type: %v", n.Type())
 	}
 
 	// Analyze assignments in func, if not analyzed before.
@@ -430,7 +430,7 @@ func (s *State) analyze(nodes ir.Nodes) {
 
 		n = n.Canonical()
 		if n.Op() != ir.ONAME {
-			base.Fatalf("n.Op = %v; want = ONAME", n.Op())
+			base.FatalfAt(n.Pos(), "n.Op = %v; want = ONAME", n.Op())
 		}
 
 		switch a := assignment.(type) {
@@ -492,14 +492,14 @@ func (s *State) analyze(nodes ir.Nodes) {
 		case ir.OAS2DOTTYPE:
 			n := n.(*ir.AssignListStmt)
 			if n.Rhs[0] == nil {
-				base.Fatalf("n.Rhs[0] == nil; n = %v", n)
+				base.FatalfAt(n.Pos(), "n.Rhs[0] == nil; n = %v", n)
 			}
 			assign(n.Lhs[0], n.Rhs[0])
 			assign(n.Lhs[1], nil) // boolean does not have methods to devirtualize
 		case ir.OAS2MAPR, ir.OAS2RECV, ir.OSELRECV2:
 			n := n.(*ir.AssignListStmt)
 			if n.Rhs[0] == nil {
-				base.Fatalf("n.Rhs[0] == nil; n = %v", n)
+				base.FatalfAt(n.Pos(), "n.Rhs[0] == nil; n = %v", n)
 			}
 			assign(n.Lhs[0], n.Rhs[0].Type())
 			assign(n.Lhs[1], nil) // boolean does not have methods to devirtualize
@@ -529,7 +529,7 @@ func (s *State) analyze(nodes ir.Nodes) {
 					assign(p, call.ReturnVars[i])
 				}
 			} else {
-				base.Fatalf("unexpected type %T in OAS2FUNC Rhs[0]", call)
+				base.FatalfAt(n.Pos(), "unexpected type %T in OAS2FUNC Rhs[0]", call)
 			}
 		case ir.ORANGE:
 			n := n.(*ir.RangeStmt)
@@ -545,7 +545,7 @@ func (s *State) analyze(nodes ir.Nodes) {
 				assign(n.Value, xTyp.Elem())
 			} else if xTyp.IsChan() {
 				assign(n.Key, xTyp.Elem())
-				base.Assertf(n.Value == nil, "n.Value != nil in range over chan")
+				base.AssertfAt(n.Value == nil, n.Pos(), "n.Value != nil in range over chan")
 			} else if xTyp.IsMap() {
 				assign(n.Key, xTyp.Key())
 				assign(n.Value, xTyp.Elem())
@@ -556,7 +556,7 @@ func (s *State) analyze(nodes ir.Nodes) {
 			} else {
 				// We will not reach here in case of an range-over-func, as it is
 				// rewrtten to function calls in the noder package.
-				base.Fatalf("range over unexpected type %v", n.X.Type())
+				base.FatalfAt(n.Pos(), "range over unexpected type %v", n.X.Type())
 			}
 		case ir.OSWITCH:
 			n := n.(*ir.SwitchStmt)

From 4dbf1a5a4c8cdb4233d17cc4fa1ca8865add6ac5 Mon Sep 17 00:00:00 2001
From: Mateusz Poliwczak 
Date: Sun, 12 Oct 2025 11:24:32 +0200
Subject: [PATCH 139/229] cmd/compile/internal/devirtualize: do not track
 assignments to non-PAUTO

We do not lookup/devirtualize such, so we can skip tracking them.

Change-Id: I8bdb0b11c694e4b2326c236093508a356a6a6964
Reviewed-on: https://go-review.googlesource.com/c/go/+/711160
Reviewed-by: Keith Randall 
Auto-Submit: Keith Randall 
Reviewed-by: Dmitri Shuralyov 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/internal/devirtualize/devirtualize.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/cmd/compile/internal/devirtualize/devirtualize.go b/src/cmd/compile/internal/devirtualize/devirtualize.go
index dfcdd42236dcca..cb4608a0246574 100644
--- a/src/cmd/compile/internal/devirtualize/devirtualize.go
+++ b/src/cmd/compile/internal/devirtualize/devirtualize.go
@@ -387,6 +387,9 @@ func (s *State) assignments(n *ir.Name) []assignment {
 	if fun == nil {
 		base.FatalfAt(n.Pos(), "n.Curfn = ")
 	}
+	if n.Class != ir.PAUTO {
+		base.FatalfAt(n.Pos(), "n.Class = %v; want = PAUTO", n.Class)
+	}
 
 	if !n.Type().IsInterface() {
 		base.FatalfAt(n.Pos(), "name passed to assignments is not of an interface type: %v", n.Type())
@@ -432,6 +435,9 @@ func (s *State) analyze(nodes ir.Nodes) {
 		if n.Op() != ir.ONAME {
 			base.FatalfAt(n.Pos(), "n.Op = %v; want = ONAME", n.Op())
 		}
+		if n.Class != ir.PAUTO {
+			return nil, -1
+		}
 
 		switch a := assignment.(type) {
 		case nil:

From 11d3d2f77d8293fe14638e74cbf52d1241b60e78 Mon Sep 17 00:00:00 2001
From: Bill Roberts 
Date: Mon, 8 Sep 2025 11:31:22 -0500
Subject: [PATCH 140/229] cmd/internal/obj/arm64: add support for PAC
 instructions

Add support for the Pointer Authentication Code instructions
required for the ELF ABI when enabling PAC aware binaries.

This allows for assembly writers to add PAC instructions where needed to
support this ABI. Follow up work is to enable the compiler to emit these
instructions in the appropriate places.

The TL;DR for the Linux ABI is that the prologue of a function that
pushes the link register (LR) to the stack, signs the LR with a key
managed by the operating system and hardware using a PAC instruction,
like "paciasp". The function epilog, when restoring the LR from the
stack will verify the signature, using an instruction like "autiasp".

This helps prevents attackers from modifying the return address on the
stack, a common technique for ROP attacks.

Details on PAC can be found here:
  - https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/enabling-pac-and-bti-on-aarch64
  - https://developer.arm.com/documentation/109576/0100/Pointer-Authentication-Code

The ABI details can be found here:
  - https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst

Change-Id: I4516ed1294d19f9ff9d278833d542821b6642aa9
Reviewed-on: https://go-review.googlesource.com/c/go/+/676675
Reviewed-by: Cherry Mui 
Reviewed-by: Joel Sing 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Dmitri Shuralyov 
---
 src/cmd/asm/internal/asm/testdata/arm64.s     |  8 ++++++
 .../asm/internal/asm/testdata/arm64error.s    |  6 +++++
 src/cmd/internal/obj/arm64/a.out.go           |  6 +++++
 src/cmd/internal/obj/arm64/anames.go          |  6 +++++
 src/cmd/internal/obj/arm64/asm7.go            | 25 +++++++++++++++++++
 5 files changed, 51 insertions(+)

diff --git a/src/cmd/asm/internal/asm/testdata/arm64.s b/src/cmd/asm/internal/asm/testdata/arm64.s
index 236f1a66979099..109a3d8316678b 100644
--- a/src/cmd/asm/internal/asm/testdata/arm64.s
+++ b/src/cmd/asm/internal/asm/testdata/arm64.s
@@ -1894,4 +1894,12 @@ next:
 	BTI	J                                  // 9f2403d5
 	BTI	JC                                 // df2403d5
 
+// Pointer Authentication Codes (PAC)
+	PACIASP                                    // 3f2303d5
+	AUTIASP                                    // bf2303d5
+	PACIBSP                                    // 7f2303d5
+	AUTIBSP                                    // ff2303d5
+	AUTIA1716                                  // 9f2103d5
+	AUTIB1716                                  // df2103d5
+
 	END
diff --git a/src/cmd/asm/internal/asm/testdata/arm64error.s b/src/cmd/asm/internal/asm/testdata/arm64error.s
index 55890ce3e631a4..ce88e3ca540f13 100644
--- a/src/cmd/asm/internal/asm/testdata/arm64error.s
+++ b/src/cmd/asm/internal/asm/testdata/arm64error.s
@@ -422,4 +422,10 @@ TEXT errors(SB),$0
 	SHA1H	V1.B16, V2.B16                                   // ERROR "invalid operands"
 	BTI                                       		 // ERROR "missing operand"
 	BTI	PLDL1KEEP					 // ERROR "illegal argument"
+	PACIASP	C                                                // ERROR "illegal combination"
+	AUTIASP	R2                                               // ERROR "illegal combination"
+	PACIBSP	R0                                               // ERROR "illegal combination"
+	AUTIBSP	C                                                // ERROR "illegal combination"
+	AUTIA1716	$45                                      // ERROR "illegal combination"
+	AUTIB1716	R0                                       // ERROR "illegal combination"
 	RET
diff --git a/src/cmd/internal/obj/arm64/a.out.go b/src/cmd/internal/obj/arm64/a.out.go
index 710dd64b304c12..814dba2c100b30 100644
--- a/src/cmd/internal/obj/arm64/a.out.go
+++ b/src/cmd/internal/obj/arm64/a.out.go
@@ -1020,6 +1020,12 @@ const (
 	AWORD
 	AYIELD
 	ABTI
+	APACIASP
+	AAUTIASP
+	APACIBSP
+	AAUTIBSP
+	AAUTIA1716
+	AAUTIB1716
 	ALAST
 	AB  = obj.AJMP
 	ABL = obj.ACALL
diff --git a/src/cmd/internal/obj/arm64/anames.go b/src/cmd/internal/obj/arm64/anames.go
index 379f53bab37cdb..497429d9985922 100644
--- a/src/cmd/internal/obj/arm64/anames.go
+++ b/src/cmd/internal/obj/arm64/anames.go
@@ -537,5 +537,11 @@ var Anames = []string{
 	"WORD",
 	"YIELD",
 	"BTI",
+	"PACIASP",
+	"AUTIASP",
+	"PACIBSP",
+	"AUTIBSP",
+	"AUTIA1716",
+	"AUTIB1716",
 	"LAST",
 }
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index 172c2256d7eede..cfb70cf08a3fd8 100644
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -3017,6 +3017,13 @@ func buildop(ctxt *obj.Link) {
 			oprangeset(ANOOP, t)
 			oprangeset(ADRPS, t)
 
+			oprangeset(APACIASP, t)
+			oprangeset(AAUTIASP, t)
+			oprangeset(APACIBSP, t)
+			oprangeset(AAUTIBSP, t)
+			oprangeset(AAUTIA1716, t)
+			oprangeset(AAUTIB1716, t)
+
 		case ACBZ:
 			oprangeset(ACBZW, t)
 			oprangeset(ACBNZ, t)
@@ -7016,6 +7023,24 @@ func (c *ctxt7) op0(p *obj.Prog, a obj.As) uint32 {
 
 	case ASEVL:
 		return SYSHINT(5)
+
+	case APACIASP:
+		return SYSHINT(25)
+
+	case AAUTIASP:
+		return SYSHINT(29)
+
+	case APACIBSP:
+		return SYSHINT(27)
+
+	case AAUTIBSP:
+		return SYSHINT(31)
+
+	case AAUTIA1716:
+		return SYSHINT(12)
+
+	case AAUTIB1716:
+		return SYSHINT(14)
 	}
 
 	c.ctxt.Diag("%v: bad op0 %v", p, a)

From ee5af46172e64eceddb56018de8ea850fe0a6cae Mon Sep 17 00:00:00 2001
From: Joe Tsai 
Date: Sat, 11 Oct 2025 11:57:46 -0700
Subject: [PATCH 141/229] encoding/json: avoid misleading errors under
 goexperiment.jsonv2

The jsontext package represents the location of JSON errors
using a JSON Pointer (RFC 6901). This uses the JSON type system.

Unfortunately the v1 json.UnmarshalTypeError assumes a Go struct-based
mechanism for reporting the location of errors
(and has historically never been implemented correctly since
it was a weird mix of both JSON and Go namespaces; see #43126).
Trying to map a JSON Pointer into UnmarshalTypeError.{Struct,Field}
is difficult to get right without teaching jsontext
about the Go type system.

To reduce the probability of misleading errors,
check whether the last token looks like a JSON array index
and if so, elide the phrase "into Go struct field".

Fixes #74801

Change-Id: Id2088ffb9c339a9238ed38c90223d86a89422842
Reviewed-on: https://go-review.googlesource.com/c/go/+/710676
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Dmitri Shuralyov 
Reviewed-by: Damien Neil 
---
 src/encoding/json/v2_decode.go      | 16 +++++++++++++++-
 src/encoding/json/v2_decode_test.go | 28 ++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/src/encoding/json/v2_decode.go b/src/encoding/json/v2_decode.go
index 1041ec7ee402d4..f17d7ebccada0a 100644
--- a/src/encoding/json/v2_decode.go
+++ b/src/encoding/json/v2_decode.go
@@ -14,6 +14,7 @@ import (
 	"fmt"
 	"reflect"
 	"strconv"
+	"strings"
 
 	"encoding/json/internal/jsonwire"
 	"encoding/json/jsontext"
@@ -119,7 +120,20 @@ type UnmarshalTypeError struct {
 func (e *UnmarshalTypeError) Error() string {
 	var s string
 	if e.Struct != "" || e.Field != "" {
-		s = "json: cannot unmarshal " + e.Value + " into Go struct field " + e.Struct + "." + e.Field + " of type " + e.Type.String()
+		// The design of UnmarshalTypeError overly assumes a struct-based
+		// Go representation for the JSON value.
+		// The logic in jsontext represents paths using a JSON Pointer,
+		// which is agnostic to the Go type system.
+		// Trying to convert a JSON Pointer into a UnmarshalTypeError.Field
+		// is difficult. As a heuristic, if the last path token looks like
+		// an index into a JSON array (e.g., ".foo.bar.0"),
+		// avoid the phrase "Go struct field ".
+		intoWhat := "Go struct field "
+		i := strings.LastIndexByte(e.Field, '.') + len(".")
+		if len(e.Field[i:]) > 0 && strings.TrimRight(e.Field[i:], "0123456789") == "" {
+			intoWhat = "" // likely a Go slice or array
+		}
+		s = "json: cannot unmarshal " + e.Value + " into " + intoWhat + e.Struct + "." + e.Field + " of type " + e.Type.String()
 	} else {
 		s = "json: cannot unmarshal " + e.Value + " into Go value of type " + e.Type.String()
 	}
diff --git a/src/encoding/json/v2_decode_test.go b/src/encoding/json/v2_decode_test.go
index 28c57ec8bf5c73..26b4448721e4ec 100644
--- a/src/encoding/json/v2_decode_test.go
+++ b/src/encoding/json/v2_decode_test.go
@@ -2363,6 +2363,34 @@ func TestUnmarshalTypeError(t *testing.T) {
 	}
 }
 
+func TestUnmarshalTypeErrorMessage(t *testing.T) {
+	err := &UnmarshalTypeError{
+		Value:  "number 5",
+		Type:   reflect.TypeFor[int](),
+		Offset: 1234,
+		Struct: "Root",
+	}
+
+	for _, tt := range []struct {
+		field string
+		want  string
+	}{
+		{"", "json: cannot unmarshal number 5 into Go struct field Root. of type int"},
+		{"1", "json: cannot unmarshal number 5 into Root.1 of type int"},
+		{"foo", "json: cannot unmarshal number 5 into Go struct field Root.foo of type int"},
+		{"foo.1", "json: cannot unmarshal number 5 into Root.foo.1 of type int"},
+		{"foo.bar", "json: cannot unmarshal number 5 into Go struct field Root.foo.bar of type int"},
+		{"foo.bar.1", "json: cannot unmarshal number 5 into Root.foo.bar.1 of type int"},
+		{"foo.bar.baz", "json: cannot unmarshal number 5 into Go struct field Root.foo.bar.baz of type int"},
+	} {
+		err.Field = tt.field
+		got := err.Error()
+		if got != tt.want {
+			t.Errorf("Error:\n\tgot:  %v\n\twant: %v", got, tt.want)
+		}
+	}
+}
+
 func TestUnmarshalSyntax(t *testing.T) {
 	var x any
 	tests := []struct {

From 3bc9d9fa8348064c33f6e69f376994af4380d3ab Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Tue, 14 Oct 2025 12:11:10 -0700
Subject: [PATCH 142/229] Revert "cmd/compile: make wasm match other platforms
 for FP->int32/64 conversions"

This reverts commit 8d810286b3121b601480426159c04d178fa29166.

Reason for revert: we need to do this more carefully, at minimum gated by a module version

Change-Id: Ia951e2e5ecdd455ea0f17567963c6fab0f4540dc
Reviewed-on: https://go-review.googlesource.com/c/go/+/711840
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/internal/ssa/_gen/Wasm.rules |  9 ++--
 src/cmd/compile/internal/ssa/_gen/WasmOps.go | 17 ++----
 src/cmd/compile/internal/ssa/opGen.go        | 56 --------------------
 src/cmd/compile/internal/ssa/rewriteWasm.go  |  8 +--
 src/cmd/compile/internal/wasm/ssa.go         | 11 ----
 test/convert5.go                             |  5 ++
 6 files changed, 17 insertions(+), 89 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/_gen/Wasm.rules b/src/cmd/compile/internal/ssa/_gen/Wasm.rules
index bb123bc3cc48e7..f632a01109f764 100644
--- a/src/cmd/compile/internal/ssa/_gen/Wasm.rules
+++ b/src/cmd/compile/internal/ssa/_gen/Wasm.rules
@@ -76,14 +76,13 @@
 (Cvt32Uto(64|32)F x) => (F(64|32)ConvertI64U (ZeroExt32to64 x))
 (Cvt64Uto(64|32)F ...) => (F(64|32)ConvertI64U ...)
 
-(Cvt32Fto32 ...) => (I32TruncSatF32S ...)
+(Cvt32Fto32 ...) => (I64TruncSatF32S ...)
 (Cvt32Fto64 ...) => (I64TruncSatF32S ...)
-(Cvt64Fto32 ...) => (I32TruncSatF64S ...)
+(Cvt64Fto32 ...) => (I64TruncSatF64S ...)
 (Cvt64Fto64 ...) => (I64TruncSatF64S ...)
-
-(Cvt32Fto32U ...) => (I32TruncSatF32U ...)
+(Cvt32Fto32U ...) => (I64TruncSatF32U ...)
 (Cvt32Fto64U ...) => (I64TruncSatF32U ...)
-(Cvt64Fto32U ...) => (I32TruncSatF64U ...)
+(Cvt64Fto32U ...) => (I64TruncSatF64U ...)
 (Cvt64Fto64U ...) => (I64TruncSatF64U ...)
 
 (Cvt32Fto64F ...) => (F64PromoteF32 ...)
diff --git a/src/cmd/compile/internal/ssa/_gen/WasmOps.go b/src/cmd/compile/internal/ssa/_gen/WasmOps.go
index b63f28a2193a2f..45bbed5f520201 100644
--- a/src/cmd/compile/internal/ssa/_gen/WasmOps.go
+++ b/src/cmd/compile/internal/ssa/_gen/WasmOps.go
@@ -222,19 +222,10 @@ func init() {
 		{name: "F64Mul", asm: "F64Mul", argLength: 2, reg: fp64_21, typ: "Float64"}, // arg0 * arg1
 		{name: "F64Div", asm: "F64Div", argLength: 2, reg: fp64_21, typ: "Float64"}, // arg0 / arg1
 
-		{name: "I64TruncSatF64S", asm: "I64TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
-		{name: "I64TruncSatF64U", asm: "I64TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
-		{name: "I64TruncSatF32S", asm: "I64TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
-		{name: "I64TruncSatF32U", asm: "I64TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
-
-		// It appears to be wasm convention that everything lands in a 64-bit register;
-		// the WASM instructions for these operations produce 32-bit width results, but
-		// wasm/ssa.go widens them appropriately to 64-bit results.
-		{name: "I32TruncSatF64S", asm: "I32TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
-		{name: "I32TruncSatF64U", asm: "I32TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
-		{name: "I32TruncSatF32S", asm: "I32TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"},  // truncates the float arg0 to a signed integer (saturating)
-		{name: "I32TruncSatF32U", asm: "I32TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Uint64"}, // truncates the float arg0 to an unsigned integer (saturating)
-
+		{name: "I64TruncSatF64S", asm: "I64TruncSatF64S", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to a signed integer (saturating)
+		{name: "I64TruncSatF64U", asm: "I64TruncSatF64U", argLength: 1, reg: regInfo{inputs: []regMask{fp64}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to an unsigned integer (saturating)
+		{name: "I64TruncSatF32S", asm: "I64TruncSatF32S", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to a signed integer (saturating)
+		{name: "I64TruncSatF32U", asm: "I64TruncSatF32U", argLength: 1, reg: regInfo{inputs: []regMask{fp32}, outputs: []regMask{gp}}, typ: "Int64"}, // truncates the float arg0 to an unsigned integer (saturating)
 		{name: "F32ConvertI64S", asm: "F32ConvertI64S", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp32}}, typ: "Float32"}, // converts the signed integer arg0 to a float
 		{name: "F32ConvertI64U", asm: "F32ConvertI64U", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp32}}, typ: "Float32"}, // converts the unsigned integer arg0 to a float
 		{name: "F64ConvertI64S", asm: "F64ConvertI64S", argLength: 1, reg: regInfo{inputs: []regMask{gp}, outputs: []regMask{fp64}}, typ: "Float64"}, // converts the signed integer arg0 to a float
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 3ed1619e4a6ab9..ee0eb657dcb14f 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -2980,10 +2980,6 @@ const (
 	OpWasmI64TruncSatF64U
 	OpWasmI64TruncSatF32S
 	OpWasmI64TruncSatF32U
-	OpWasmI32TruncSatF64S
-	OpWasmI32TruncSatF64U
-	OpWasmI32TruncSatF32S
-	OpWasmI32TruncSatF32U
 	OpWasmF32ConvertI64S
 	OpWasmF32ConvertI64U
 	OpWasmF64ConvertI64S
@@ -40294,58 +40290,6 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
-	{
-		name:   "I32TruncSatF64S",
-		argLen: 1,
-		asm:    wasm.AI32TruncSatF64S,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 281470681743360}, // F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
-			},
-			outputs: []outputInfo{
-				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
-			},
-		},
-	},
-	{
-		name:   "I32TruncSatF64U",
-		argLen: 1,
-		asm:    wasm.AI32TruncSatF64U,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 281470681743360}, // F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31
-			},
-			outputs: []outputInfo{
-				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
-			},
-		},
-	},
-	{
-		name:   "I32TruncSatF32S",
-		argLen: 1,
-		asm:    wasm.AI32TruncSatF32S,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 4294901760}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15
-			},
-			outputs: []outputInfo{
-				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
-			},
-		},
-	},
-	{
-		name:   "I32TruncSatF32U",
-		argLen: 1,
-		asm:    wasm.AI32TruncSatF32U,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 4294901760}, // F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15
-			},
-			outputs: []outputInfo{
-				{0, 65535}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15
-			},
-		},
-	},
 	{
 		name:   "F32ConvertI64S",
 		argLen: 1,
diff --git a/src/cmd/compile/internal/ssa/rewriteWasm.go b/src/cmd/compile/internal/ssa/rewriteWasm.go
index dd73d3a5e705ed..a164a6eee555b9 100644
--- a/src/cmd/compile/internal/ssa/rewriteWasm.go
+++ b/src/cmd/compile/internal/ssa/rewriteWasm.go
@@ -120,10 +120,10 @@ func rewriteValueWasm(v *Value) bool {
 		v.Op = OpWasmI64Ctz
 		return true
 	case OpCvt32Fto32:
-		v.Op = OpWasmI32TruncSatF32S
+		v.Op = OpWasmI64TruncSatF32S
 		return true
 	case OpCvt32Fto32U:
-		v.Op = OpWasmI32TruncSatF32U
+		v.Op = OpWasmI64TruncSatF32U
 		return true
 	case OpCvt32Fto64:
 		v.Op = OpWasmI64TruncSatF32S
@@ -143,13 +143,13 @@ func rewriteValueWasm(v *Value) bool {
 	case OpCvt32to64F:
 		return rewriteValueWasm_OpCvt32to64F(v)
 	case OpCvt64Fto32:
-		v.Op = OpWasmI32TruncSatF64S
+		v.Op = OpWasmI64TruncSatF64S
 		return true
 	case OpCvt64Fto32F:
 		v.Op = OpWasmF32DemoteF64
 		return true
 	case OpCvt64Fto32U:
-		v.Op = OpWasmI32TruncSatF64U
+		v.Op = OpWasmI64TruncSatF64U
 		return true
 	case OpCvt64Fto64:
 		v.Op = OpWasmI64TruncSatF64S
diff --git a/src/cmd/compile/internal/wasm/ssa.go b/src/cmd/compile/internal/wasm/ssa.go
index 8ebc90288572a3..1e3b318e8c9fe0 100644
--- a/src/cmd/compile/internal/wasm/ssa.go
+++ b/src/cmd/compile/internal/wasm/ssa.go
@@ -430,17 +430,6 @@ func ssaGenValueOnStack(s *ssagen.State, v *ssa.Value, extend bool) {
 		getValue64(s, v.Args[0])
 		s.Prog(v.Op.Asm())
 
-		// 32-bit integer conversion results
-	case ssa.OpWasmI32TruncSatF32S, ssa.OpWasmI32TruncSatF64S:
-		getValue64(s, v.Args[0])
-		s.Prog(v.Op.Asm())
-		s.Prog(wasm.AI64ExtendI32S)
-
-	case ssa.OpWasmI32TruncSatF32U, ssa.OpWasmI32TruncSatF64U:
-		getValue64(s, v.Args[0])
-		s.Prog(v.Op.Asm())
-		s.Prog(wasm.AI64ExtendI32U)
-
 	case ssa.OpWasmF32DemoteF64:
 		getValue64(s, v.Args[0])
 		s.Prog(v.Op.Asm())
diff --git a/test/convert5.go b/test/convert5.go
index 4688fae85587d4..27aa7867f42824 100644
--- a/test/convert5.go
+++ b/test/convert5.go
@@ -4,6 +4,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !wasm
+
+// TODO fix this to work for wasm
+// Doing more than this, however, expands the change.
+
 package main
 
 import (

From bb2a14252b989f89665d17b66417eff815200e3b Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Tue, 14 Oct 2025 12:12:12 -0700
Subject: [PATCH 143/229] Revert "runtime: adjust softfloat corner cases to
 match amd64/arm64"

This reverts commit b9f3accdcf973ca41069e22e6859b9436801aae5.

Reason for revert: we need to do this more carefully, at minimum gated by a module version

(This should follow the WASM FP conversion revert)

Change-Id: Ib98ce7d243348f69c9944db8537397b225c2cc33
Reviewed-on: https://go-review.googlesource.com/c/go/+/711841
Reviewed-by: Keith Randall 
TryBot-Bypass: David Chase 
Reviewed-by: Keith Randall 
---
 src/runtime/export_test.go      |  1 -
 src/runtime/softfloat64.go      | 93 ++++++++-------------------------
 src/runtime/softfloat64_test.go | 33 +-----------
 test/convert5.go                |  5 --
 4 files changed, 25 insertions(+), 107 deletions(-)

diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index f61cac763cef3d..9f2fcacc30ee5c 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -25,7 +25,6 @@ var F32to64 = f32to64
 var Fcmp64 = fcmp64
 var Fintto64 = fintto64
 var F64toint = f64toint
-var F64touint = f64touint64
 
 var Entersyscall = entersyscall
 var Exitsyscall = exitsyscall
diff --git a/src/runtime/softfloat64.go b/src/runtime/softfloat64.go
index 7b9409f75be380..42ef0092970b3e 100644
--- a/src/runtime/softfloat64.go
+++ b/src/runtime/softfloat64.go
@@ -26,11 +26,6 @@ const (
 	neg32 uint32 = 1 << (expbits32 + mantbits32)
 )
 
-// If F is not NaN and not Inf, then f == (-1)**sign * mantissa * 2**(exp-52)
-// The mantissa and exp are adjusted from their stored representation  so
-// that the mantissa includes the formerly implicit 1, the exponent bias
-// is removed, and denormalized floats to put a 1 in the expected
-// (1<= 63: // |f| >= 2^63, including infinity
+	case fe > 63: // f >= 2^63
+		if fs != 0 && fm == 0 { // f == -2^63
+			return -1 << 63, true
+		}
 		if fs != 0 {
-			return -0x8000_0000_0000_0000, true
+			return 0, false
 		}
-		return 0x7fff_ffff_ffff_ffff, true
+		return 0, false
 	}
 
 	for fe > int(mantbits64) {
@@ -406,51 +400,12 @@ func f64toint(f uint64) (val int64, isNan bool) {
 		fm >>= 1
 	}
 	val = int64(fm)
-	if val < 0 {
-		if fs != 0 {
-			return -0x8000_0000_0000_0000, true
-		}
-		return 0x7fff_ffff_ffff_ffff, true
-	}
 	if fs != 0 {
 		val = -val
 	}
 	return val, true
 }
 
-// returns saturated-conversion uint64 value of f
-// and whether the input was NaN (in which case it
-// may not match the "hardware" conversion).
-func f64touint(f uint64) (val uint64, isNan bool) {
-	fs, fm, fe, fi, fn := funpack64(f)
-
-	switch {
-
-	case fn: // NaN
-		return 0xffff_ffff_ffff_ffff, false
-
-	case fs != 0: // all negative, including -Inf, are zero
-		return 0, true
-
-	case fi || fe >= 64: // positive infinity or f >= 2^64
-		return 0xffff_ffff_ffff_ffff, true
-
-	case fe < -1: // f < 0.5
-		return 0, true
-	}
-
-	for fe > int(mantbits64) {
-		fe--
-		fm <<= 1
-	}
-	for fe < int(mantbits64) {
-		fe++
-		fm >>= 1
-	}
-	val = fm
-	return val, true
-}
-
 func fintto64(val int64) (f uint64) {
 	fs := uint64(val) & (1 << 63)
 	mant := uint64(val)
@@ -609,12 +564,6 @@ func fint64to64(x int64) uint64 {
 
 func f32toint32(x uint32) int32 {
 	val, _ := f64toint(f32to64(x))
-	if val >= 0x7fffffff {
-		return 0x7fffffff
-	}
-	if val < -0x80000000 {
-		return -0x80000000
-	}
 	return int32(val)
 }
 
@@ -625,12 +574,6 @@ func f32toint64(x uint32) int64 {
 
 func f64toint32(x uint64) int32 {
 	val, _ := f64toint(x)
-	if val >= 0x7fffffff {
-		return 0x7fffffff
-	}
-	if val < -0x80000000 {
-		return -0x80000000
-	}
 	return int32(val)
 }
 
@@ -640,13 +583,23 @@ func f64toint64(x uint64) int64 {
 }
 
 func f64touint64(x uint64) uint64 {
-	val, _ := f64touint(x)
-	return val
+	var m uint64 = 0x43e0000000000000 // float64 1<<63
+	if fgt64(m, x) {
+		return uint64(f64toint64(x))
+	}
+	y := fadd64(x, -m)
+	z := uint64(f64toint64(y))
+	return z | (1 << 63)
 }
 
 func f32touint64(x uint32) uint64 {
-	val, _ := f64touint(f32to64(x))
-	return val
+	var m uint32 = 0x5f000000 // float32 1<<63
+	if fgt32(m, x) {
+		return uint64(f32toint64(x))
+	}
+	y := fadd32(x, -m)
+	z := uint64(f32toint64(y))
+	return z | (1 << 63)
 }
 
 func fuint64to64(x uint64) uint64 {
diff --git a/src/runtime/softfloat64_test.go b/src/runtime/softfloat64_test.go
index 233d5e01c0ea60..3f53e8bc55810c 100644
--- a/src/runtime/softfloat64_test.go
+++ b/src/runtime/softfloat64_test.go
@@ -28,15 +28,6 @@ func div(x, y float64) float64 { return x / y }
 func TestFloat64(t *testing.T) {
 	base := []float64{
 		0,
-		1,
-		-9223372036854775808,
-		-9223372036854775808 + 4096,
-		18446744073709551615,
-		18446744073709551615 + 1,
-		18446744073709551615 - 1,
-		9223372036854775808 + 4096,
-		0.5,
-		0.75,
 		math.Copysign(0, -1),
 		-1,
 		1,
@@ -44,8 +35,6 @@ func TestFloat64(t *testing.T) {
 		math.Inf(+1),
 		math.Inf(-1),
 		0.1,
-		0.5,
-		0.75,
 		1.5,
 		1.9999999999999998,     // all 1s mantissa
 		1.3333333333333333,     // 1.010101010101...
@@ -81,7 +70,7 @@ func TestFloat64(t *testing.T) {
 		1e+307,
 		1e+308,
 	}
-	all := make([]float64, 250)
+	all := make([]float64, 200)
 	copy(all, base)
 	for i := len(base); i < len(all); i++ {
 		all[i] = rand.NormFloat64()
@@ -93,7 +82,6 @@ func TestFloat64(t *testing.T) {
 		test(t, "*", mul, fop(Fmul64), all)
 		test(t, "/", div, fop(Fdiv64), all)
 	}
-
 }
 
 // 64 -hw-> 32 -hw-> 64
@@ -116,11 +104,6 @@ func hwint64(f float64) float64 {
 	return float64(int64(f))
 }
 
-// float64 -hw-> uint64 -hw-> float64
-func hwuint64(f float64) float64 {
-	return float64(uint64(f))
-}
-
 // float64 -hw-> int32 -hw-> float64
 func hwint32(f float64) float64 {
 	return float64(int32(f))
@@ -130,23 +113,13 @@ func hwint32(f float64) float64 {
 func toint64sw(f float64) float64 {
 	i, ok := F64toint(math.Float64bits(f))
 	if !ok {
-		// There's no right answer for NaN.
+		// There's no right answer for out of range.
 		// Match the hardware to pass the test.
 		i = int64(f)
 	}
 	return float64(i)
 }
 
-func touint64sw(f float64) float64 {
-	i := F64touint(math.Float64bits(f))
-	if f != f {
-		// There's no right answer for NaN.
-		// Match the hardware to pass the test.
-		i = uint64(f)
-	}
-	return float64(i)
-}
-
 // float64 -hw-> int64 -sw-> float64
 func fromint64sw(f float64) float64 {
 	return math.Float64frombits(Fintto64(int64(f)))
@@ -177,7 +150,6 @@ func test(t *testing.T, op string, hw, sw func(float64, float64) float64, all []
 			testu(t, "to32", trunc32, to32sw, h)
 			testu(t, "to64", trunc32, to64sw, h)
 			testu(t, "toint64", hwint64, toint64sw, h)
-			testu(t, "touint64", hwuint64, touint64sw, h)
 			testu(t, "fromint64", hwint64, fromint64sw, h)
 			testcmp(t, f, h)
 			testcmp(t, h, f)
@@ -191,7 +163,6 @@ func testu(t *testing.T, op string, hw, sw func(float64) float64, v float64) {
 	h := hw(v)
 	s := sw(v)
 	if !same(h, s) {
-		s = sw(v) // debug me
 		err(t, "%s %g = sw %g, hw %g\n", op, v, s, h)
 	}
 }
diff --git a/test/convert5.go b/test/convert5.go
index 27aa7867f42824..57585ef76e1673 100644
--- a/test/convert5.go
+++ b/test/convert5.go
@@ -62,8 +62,6 @@ func main() {
 	p64_plus4k_plus1 := id(float64(p64 + 4096 + 1)) // want this to be precise and fit in 53 bits mantissa
 	n32_minus4k := id(float32(n32 - 4096))
 	n64_minus4k := id(float64(n64 - 4096))
-	n32_plus4k := id(float32(n32 + 4096))
-	n64_plus4k := id(float64(n64 + 4096))
 	inf_32 := id(float32(one / 0))
 	inf_64 := id(float64(one / 0))
 	ninf_32 := id(float32(-one / 0))
@@ -81,7 +79,6 @@ func main() {
 		{"p64_plus4k_plus1", p64_plus4k_plus1, p32},
 		{"n32_minus4k", n32_minus4k, n32},
 		{"n64_minus4k", n64_minus4k, n32},
-		{"n32_plus4k", n32_plus4k, n32 + 4096},
 		{"inf_32", inf_32, p32},
 		{"inf_64", inf_64, p32},
 		{"ninf_32", ninf_32, n32},
@@ -111,8 +108,6 @@ func main() {
 		{"p64_plus4k_plus1", p64_plus4k_plus1, p64},
 		{"n32_minus4k", n32_minus4k, n32 - 4096},
 		{"n64_minus4k", n64_minus4k, n64},
-		{"n32_plus4k", n32_plus4k, n32 + 4096},
-		{"n64_plus4k", n64_plus4k, n64 + 4096},
 		{"inf_32", inf_32, p64},
 		{"inf_64", inf_64, p64},
 		{"ninf_32", ninf_32, n64},

From 6d5b13793f51c77e7ea730ca140d5c1cb583af92 Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Tue, 14 Oct 2025 12:13:14 -0700
Subject: [PATCH 144/229] Revert "cmd/compile: make 386 float-to-int
 conversions match amd64"

This reverts commit 78d75b37992be01326b9bd2666195aaba9bf2ae2.

Reason for revert: we need to do this more carefully, at minimum gated by a module version

(This should follow the softfloat FP conversion revert)

Change-Id: I736bec6cd860285dcc3b11fac85b377a149435c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/711842
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/internal/ssa/_gen/386.rules |  6 +-
 src/cmd/compile/internal/ssa/_gen/386Ops.go |  2 -
 src/cmd/compile/internal/ssa/opGen.go       | 13 ---
 src/cmd/compile/internal/ssa/rewrite386.go  | 99 +--------------------
 src/cmd/compile/internal/x86/ssa.go         |  7 --
 src/runtime/asm_386.s                       | 10 +++
 src/runtime/stubs_386.go                    |  1 +
 src/runtime/vlrt.go                         | 63 +------------
 test/convert5.go                            |  4 +-
 9 files changed, 23 insertions(+), 182 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/_gen/386.rules b/src/cmd/compile/internal/ssa/_gen/386.rules
index 4e3d3203c79041..5f1150241929eb 100644
--- a/src/cmd/compile/internal/ssa/_gen/386.rules
+++ b/src/cmd/compile/internal/ssa/_gen/386.rules
@@ -88,10 +88,8 @@
 (Cvt32to32F ...) => (CVTSL2SS ...)
 (Cvt32to64F ...) => (CVTSL2SD ...)
 
-(Cvt32Fto32  x) && base.ConvertHash.MatchPos(v.Pos, nil) => (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSS2SL  x) (NOTL  (MOVLf2i x)))))
-(Cvt64Fto32  x) && base.ConvertHash.MatchPos(v.Pos, nil) => (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSD2SL  x) (NOTL  (MOVLf2i (CVTSD2SS  x))))))
-(Cvt32Fto32  x) && !base.ConvertHash.MatchPos(v.Pos, nil) => (CVTTSS2SL  x)
-(Cvt64Fto32  x) && !base.ConvertHash.MatchPos(v.Pos, nil) => (CVTTSD2SL  x)
+(Cvt32Fto32 ...) => (CVTTSS2SL ...)
+(Cvt64Fto32 ...) => (CVTTSD2SL ...)
 
 (Cvt32Fto64F ...) => (CVTSS2SD ...)
 (Cvt64Fto32F ...) => (CVTSD2SS ...)
diff --git a/src/cmd/compile/internal/ssa/_gen/386Ops.go b/src/cmd/compile/internal/ssa/_gen/386Ops.go
index 86c2f9c8f080f8..60599a33abb587 100644
--- a/src/cmd/compile/internal/ssa/_gen/386Ops.go
+++ b/src/cmd/compile/internal/ssa/_gen/386Ops.go
@@ -342,8 +342,6 @@ func init() {
 		{name: "MOVWLSX", argLength: 1, reg: gp11, asm: "MOVWLSX"}, // sign extend arg0 from int16 to int32
 		{name: "MOVWLZX", argLength: 1, reg: gp11, asm: "MOVWLZX"}, // zero extend arg0 from int16 to int32
 
-		{name: "MOVLf2i", argLength: 1, reg: fpgp, typ: "UInt32"}, // move 32 bits from float to int reg, zero extend
-
 		{name: "MOVLconst", reg: gp01, asm: "MOVL", typ: "UInt32", aux: "Int32", rematerializeable: true}, // 32 low bits of auxint
 
 		{name: "CVTTSD2SL", argLength: 1, reg: fpgp, asm: "CVTTSD2SL"}, // convert float64 to int32
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index ee0eb657dcb14f..9b38e66a23f019 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -499,7 +499,6 @@ const (
 	Op386MOVBLZX
 	Op386MOVWLSX
 	Op386MOVWLZX
-	Op386MOVLf2i
 	Op386MOVLconst
 	Op386CVTTSD2SL
 	Op386CVTTSS2SL
@@ -5602,18 +5601,6 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
-	{
-		name:   "MOVLf2i",
-		argLen: 1,
-		reg: regInfo{
-			inputs: []inputInfo{
-				{0, 65280}, // X0 X1 X2 X3 X4 X5 X6 X7
-			},
-			outputs: []outputInfo{
-				{0, 239}, // AX CX DX BX BP SI DI
-			},
-		},
-	},
 	{
 		name:              "MOVLconst",
 		auxType:           auxInt32,
diff --git a/src/cmd/compile/internal/ssa/rewrite386.go b/src/cmd/compile/internal/ssa/rewrite386.go
index 4845f1e0250ea8..0495438710659e 100644
--- a/src/cmd/compile/internal/ssa/rewrite386.go
+++ b/src/cmd/compile/internal/ssa/rewrite386.go
@@ -3,7 +3,6 @@
 package ssa
 
 import "math"
-import "cmd/compile/internal/base"
 import "cmd/compile/internal/types"
 
 func rewriteValue386(v *Value) bool {
@@ -341,7 +340,8 @@ func rewriteValue386(v *Value) bool {
 		v.Op = Op386BSFL
 		return true
 	case OpCvt32Fto32:
-		return rewriteValue386_OpCvt32Fto32(v)
+		v.Op = Op386CVTTSS2SL
+		return true
 	case OpCvt32Fto64F:
 		v.Op = Op386CVTSS2SD
 		return true
@@ -352,7 +352,8 @@ func rewriteValue386(v *Value) bool {
 		v.Op = Op386CVTSL2SD
 		return true
 	case OpCvt64Fto32:
-		return rewriteValue386_OpCvt64Fto32(v)
+		v.Op = Op386CVTTSD2SL
+		return true
 	case OpCvt64Fto32F:
 		v.Op = Op386CVTSD2SS
 		return true
@@ -7963,98 +7964,6 @@ func rewriteValue386_OpCtz8(v *Value) bool {
 		return true
 	}
 }
-func rewriteValue386_OpCvt32Fto32(v *Value) bool {
-	v_0 := v.Args[0]
-	b := v.Block
-	typ := &b.Func.Config.Types
-	// match: (Cvt32Fto32  x)
-	// cond: base.ConvertHash.MatchPos(v.Pos, nil)
-	// result: (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSS2SL  x) (NOTL  (MOVLf2i x)))))
-	for {
-		t := v.Type
-		x := v_0
-		if !(base.ConvertHash.MatchPos(v.Pos, nil)) {
-			break
-		}
-		v.reset(Op386XORL)
-		v.Type = t
-		v0 := b.NewValue0(v.Pos, Op386SARLconst, t)
-		v0.AuxInt = int32ToAuxInt(31)
-		v1 := b.NewValue0(v.Pos, Op386ANDL, t)
-		y := b.NewValue0(v.Pos, Op386CVTTSS2SL, t)
-		y.AddArg(x)
-		v3 := b.NewValue0(v.Pos, Op386NOTL, typ.Int32)
-		v4 := b.NewValue0(v.Pos, Op386MOVLf2i, typ.UInt32)
-		v4.AddArg(x)
-		v3.AddArg(v4)
-		v1.AddArg2(y, v3)
-		v0.AddArg(v1)
-		v.AddArg2(y, v0)
-		return true
-	}
-	// match: (Cvt32Fto32  x)
-	// cond: !base.ConvertHash.MatchPos(v.Pos, nil)
-	// result: (CVTTSS2SL  x)
-	for {
-		t := v.Type
-		x := v_0
-		if !(!base.ConvertHash.MatchPos(v.Pos, nil)) {
-			break
-		}
-		v.reset(Op386CVTTSS2SL)
-		v.Type = t
-		v.AddArg(x)
-		return true
-	}
-	return false
-}
-func rewriteValue386_OpCvt64Fto32(v *Value) bool {
-	v_0 := v.Args[0]
-	b := v.Block
-	typ := &b.Func.Config.Types
-	// match: (Cvt64Fto32  x)
-	// cond: base.ConvertHash.MatchPos(v.Pos, nil)
-	// result: (XORL  y (SARLconst  [31] (ANDL  y:(CVTTSD2SL  x) (NOTL  (MOVLf2i (CVTSD2SS  x))))))
-	for {
-		t := v.Type
-		x := v_0
-		if !(base.ConvertHash.MatchPos(v.Pos, nil)) {
-			break
-		}
-		v.reset(Op386XORL)
-		v.Type = t
-		v0 := b.NewValue0(v.Pos, Op386SARLconst, t)
-		v0.AuxInt = int32ToAuxInt(31)
-		v1 := b.NewValue0(v.Pos, Op386ANDL, t)
-		y := b.NewValue0(v.Pos, Op386CVTTSD2SL, t)
-		y.AddArg(x)
-		v3 := b.NewValue0(v.Pos, Op386NOTL, typ.Int32)
-		v4 := b.NewValue0(v.Pos, Op386MOVLf2i, typ.UInt32)
-		v5 := b.NewValue0(v.Pos, Op386CVTSD2SS, typ.Float32)
-		v5.AddArg(x)
-		v4.AddArg(v5)
-		v3.AddArg(v4)
-		v1.AddArg2(y, v3)
-		v0.AddArg(v1)
-		v.AddArg2(y, v0)
-		return true
-	}
-	// match: (Cvt64Fto32  x)
-	// cond: !base.ConvertHash.MatchPos(v.Pos, nil)
-	// result: (CVTTSD2SL  x)
-	for {
-		t := v.Type
-		x := v_0
-		if !(!base.ConvertHash.MatchPos(v.Pos, nil)) {
-			break
-		}
-		v.reset(Op386CVTTSD2SL)
-		v.Type = t
-		v.AddArg(x)
-		return true
-	}
-	return false
-}
 func rewriteValue386_OpDiv8(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
diff --git a/src/cmd/compile/internal/x86/ssa.go b/src/cmd/compile/internal/x86/ssa.go
index 2858a81b4b977b..d0aad088496351 100644
--- a/src/cmd/compile/internal/x86/ssa.go
+++ b/src/cmd/compile/internal/x86/ssa.go
@@ -538,13 +538,6 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.To.Type = obj.TYPE_MEM
 		p.To.Reg = v.Args[0].Reg()
 		ssagen.AddAux(&p.To, v)
-	case ssa.Op386MOVLf2i:
-		var p *obj.Prog
-		p = s.Prog(x86.AMOVL)
-		p.From.Type = obj.TYPE_REG
-		p.From.Reg = v.Args[0].Reg()
-		p.To.Type = obj.TYPE_REG
-		p.To.Reg = v.Reg()
 	case ssa.Op386ADDLconstmodify:
 		sc := v.AuxValAndOff()
 		val := sc.Val()
diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index 2a6de64f9fbdb3..df32e90fda8416 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -1407,6 +1407,16 @@ TEXT runtime·uint32tofloat64(SB),NOSPLIT,$8-12
 	FMOVDP	F0, ret+4(FP)
 	RET
 
+TEXT runtime·float64touint32(SB),NOSPLIT,$12-12
+	FMOVD	a+0(FP), F0
+	FSTCW	0(SP)
+	FLDCW	runtime·controlWord64trunc(SB)
+	FMOVVP	F0, 4(SP)
+	FLDCW	0(SP)
+	MOVL	4(SP), AX
+	MOVL	AX, ret+8(FP)
+	RET
+
 // gcWriteBarrier informs the GC about heap pointer writes.
 //
 // gcWriteBarrier returns space in a write barrier buffer which
diff --git a/src/runtime/stubs_386.go b/src/runtime/stubs_386.go
index 4f3dcd4fd9b250..a1dd023974a0c6 100644
--- a/src/runtime/stubs_386.go
+++ b/src/runtime/stubs_386.go
@@ -6,6 +6,7 @@ package runtime
 
 import "unsafe"
 
+func float64touint32(a float64) uint32
 func uint32tofloat64(a uint32) float64
 
 // stackcheck checks that SP is in range [g->stack.lo, g->stack.hi).
diff --git a/src/runtime/vlrt.go b/src/runtime/vlrt.go
index 511eb0dd4edf40..4b12f593c8a8ec 100644
--- a/src/runtime/vlrt.go
+++ b/src/runtime/vlrt.go
@@ -40,17 +40,10 @@ func float64toint64(d float64) (y uint64) {
 }
 
 func float64touint64(d float64) (y uint64) {
-	_d2vu(&y, d)
+	_d2v(&y, d)
 	return
 }
 
-func float64touint32(a float64) uint32 {
-	if a >= 0xffffffff {
-		return 0xffffffff
-	}
-	return uint32(float64touint64(a))
-}
-
 func int64tofloat64(y int64) float64 {
 	if y < 0 {
 		return -uint64tofloat64(-uint64(y))
@@ -124,16 +117,12 @@ func _d2v(y *uint64, d float64) {
 	} else {
 		/* v = (hi||lo) << -sh */
 		sh := uint32(-sh)
-		if sh <= 10 {
+		if sh <= 11 {
 			ylo = xlo << sh
 			yhi = xhi<>(32-sh)
 		} else {
-			if x&sign64 != 0 {
-				*y = 0x8000000000000000
-			} else {
-				*y = 0x7fffffffffffffff
-			}
-			return
+			/* overflow */
+			yhi = uint32(d) /* causes something awful */
 		}
 	}
 	if x&sign64 != 0 {
@@ -147,50 +136,6 @@ func _d2v(y *uint64, d float64) {
 
 	*y = uint64(yhi)<<32 | uint64(ylo)
 }
-func _d2vu(y *uint64, d float64) {
-	x := *(*uint64)(unsafe.Pointer(&d))
-	if x&sign64 != 0 {
-		*y = 0
-		return
-	}
-
-	xhi := uint32(x>>32)&0xfffff | 0x100000
-	xlo := uint32(x)
-	sh := 1075 - int32(uint32(x>>52)&0x7ff)
-
-	var ylo, yhi uint32
-	if sh >= 0 {
-		sh := uint32(sh)
-		/* v = (hi||lo) >> sh */
-		if sh < 32 {
-			if sh == 0 {
-				ylo = xlo
-				yhi = xhi
-			} else {
-				ylo = xlo>>sh | xhi<<(32-sh)
-				yhi = xhi >> sh
-			}
-		} else {
-			if sh == 32 {
-				ylo = xhi
-			} else if sh < 64 {
-				ylo = xhi >> (sh - 32)
-			}
-		}
-	} else {
-		/* v = (hi||lo) << -sh */
-		sh := uint32(-sh)
-		if sh <= 11 {
-			ylo = xlo << sh
-			yhi = xhi<>(32-sh)
-		} else {
-			/* overflow */
-			*y = 0xffffffffffffffff
-			return
-		}
-	}
-	*y = uint64(yhi)<<32 | uint64(ylo)
-}
 func uint64div(n, d uint64) uint64 {
 	// Check for 32 bit operands
 	if uint32(n>>32) == 0 && uint32(d>>32) == 0 {
diff --git a/test/convert5.go b/test/convert5.go
index 57585ef76e1673..1bd74abdad0715 100644
--- a/test/convert5.go
+++ b/test/convert5.go
@@ -4,9 +4,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !wasm
+//go:build !wasm && !386 && !arm && !mips
 
-// TODO fix this to work for wasm
+// TODO fix this to work for wasm and 32-bit architectures.
 // Doing more than this, however, expands the change.
 
 package main

From 7056c71d320bea2e1cafbb4f8863513ed50a4256 Mon Sep 17 00:00:00 2001
From: David Chase 
Date: Tue, 14 Oct 2025 16:18:49 -0400
Subject: [PATCH 145/229] cmd/compile: disable use of new saturating
 float-to-int conversions

The new conversions can be activated (or bisected) with
  -gcflags=all=-d=converthash=PATTERN

where PATTERN is either a hash string or n, qn, y, qy for
no, quietly no, yes, quietly yes.

This CL makes the default pattern be "qn" instead of the
default-default which is an efficient encoding of "qy".

Updates #75834

Change-Id: I88a9fd7880bc999132420c8d0a22a8fdc1e95a2a
Reviewed-on: https://go-review.googlesource.com/c/go/+/711845
Reviewed-by: Cherry Mui 
TryBot-Bypass: David Chase 
---
 src/cmd/compile/internal/base/flag.go | 3 +++
 test/codegen/math.go                  | 2 +-
 test/convert5.go                      | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/cmd/compile/internal/base/flag.go b/src/cmd/compile/internal/base/flag.go
index 1ac2cecc61ec7e..1d211e0a2dd9f4 100644
--- a/src/cmd/compile/internal/base/flag.go
+++ b/src/cmd/compile/internal/base/flag.go
@@ -264,6 +264,9 @@ func ParseFlags() {
 
 	if Debug.Converthash != "" {
 		ConvertHash = NewHashDebug("converthash", Debug.Converthash, nil)
+	} else {
+		// quietly disable the convert hash changes
+		ConvertHash = NewHashDebug("converthash", "qn", nil)
 	}
 	if Debug.Fmahash != "" {
 		FmaHash = NewHashDebug("fmahash", Debug.Fmahash, nil)
diff --git a/test/codegen/math.go b/test/codegen/math.go
index 5787657d2bc3df..9ef881a9afc2f5 100644
--- a/test/codegen/math.go
+++ b/test/codegen/math.go
@@ -1,4 +1,4 @@
-// asmcheck
+// asmcheck -gcflags=-d=converthash=qy
 
 // Copyright 2018 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
diff --git a/test/convert5.go b/test/convert5.go
index 1bd74abdad0715..df247ca0b9b238 100644
--- a/test/convert5.go
+++ b/test/convert5.go
@@ -1,4 +1,4 @@
-// run
+// run -gcflags=-d=converthash=qy
 
 // Copyright 2020 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style

From 36086e85f842e8ed2c03be2542a6cc211603abbc Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 2 Oct 2025 11:15:34 -0400
Subject: [PATCH 146/229] cmd/go: create temporary cleanup script

This is a large series of sed commands to cleanup after successful use
of the `rf inject` command.  This script will be used to refactor the
codebase to eliminate global state within the module loader.  Once
that effort is complete, this script will be removed.

This commit is part of the overall effort to eliminate global
modloader state.

Change-Id: If04926b5ca5b7230f91ac98fe4a82c20ef5f73ee
Reviewed-on: https://go-review.googlesource.com/c/go/+/709978
Reviewed-by: Michael Matloob 
TryBot-Bypass: Ian Alexander 
Commit-Queue: Ian Alexander 
Reviewed-by: Michael Pratt 
---
 src/cmd/go/internal/rf-cleanup.zsh | 43 ++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100755 src/cmd/go/internal/rf-cleanup.zsh

diff --git a/src/cmd/go/internal/rf-cleanup.zsh b/src/cmd/go/internal/rf-cleanup.zsh
new file mode 100755
index 00000000000000..c805db56e3611e
--- /dev/null
+++ b/src/cmd/go/internal/rf-cleanup.zsh
@@ -0,0 +1,43 @@
+#!/usr/bin/env zsh
+
+set -eu -o pipefail
+
+# This is a large series of sed commands to cleanup after successful use of the
+# `rf inject` command.  This script will be used to refactor the codebase to
+# eliminate global state within the module loader.  Once that effort is
+# complete, this script will be removed.
+
+find . -name '*.go' -exec \
+  sed -i '
+    #
+    # CompileAction does not use loaderstate.
+    #
+    s/CompileAction(loaderstate[^ ]* \*modload.State, /CompileAction(/g
+    s/CompileAction(modload.LoaderState[^,]*, /CompileAction(/g
+    s/CompileAction(loaderstate[^,]*, /CompileAction(/g
+    #
+    # cgoAction does not use loaderstate.
+    #
+    s/cgoAction(loaderstate \*modload\.State, /cgoAction(/g
+    s/cgoAction(loaderstate, /cgoAction(/g
+    s/cgoAction(loaderstate_, /cgoAction(/g
+    #
+    # Remove redundant mentions of LoaderState from function call sites.
+    #
+    s/(modload\.LoaderState_*, loaderstate,/(loaderstate,/g
+    s/(modload\.LoaderState_*, moduleLoaderState,/(moduleLoaderState,/g
+    s/(modload\.LoaderState_*, modload\.LoaderState/(modload.LoaderState/g
+    s/(modload\.LoaderState_*, loaderstate,/(loaderstate,/g
+    s/(modload\.LoaderState_*, moduleLoaderState,/(moduleLoaderState,/g
+    s/(modload\.LoaderState_*, modload\.LoaderState,/(modload.LoaderState,/g
+    s/(loaderstate_* \*modload.State, loaderstate \*modload.State/(loaderstate *modload.State/g
+    s/(loaderstate_* \*State, loaderstate \*State/(loaderstate *State/g
+    s/(loaderstate_*, loaderstate,/(loaderstate,/g
+    s/(LoaderState_*, loaderstate,/(loaderstate,/g
+    s/(LoaderState_*, loaderState,/(loaderState,/g
+    s/(LoaderState_*, LoaderState,/(LoaderState,/g
+    s/(LoaderState_*, LoaderState,/(LoaderState,/g
+    s/(moduleLoaderState_*, loaderstate,/(loaderstate,/g
+    s/(moduleLoaderState_*, moduleLoaderState,/(moduleLoaderState,/g
+  ' {} \;
+

From 51134968050270a08d6a2456d0ea72c8a99b6e96 Mon Sep 17 00:00:00 2001
From: matloob 
Date: Wed, 15 Oct 2025 11:23:59 -0400
Subject: [PATCH 147/229] runtime/pprof: skip flaky test
 TestProfilerStackDepth/heap for now

The test has been causing a lot of flakes on the builders. Skip it while
I'm debugging it.

For #74029

Change-Id: I6a6a696450c23f65bc310a2d0ab61b22dba88f00
Reviewed-on: https://go-review.googlesource.com/c/go/+/712060
TryBot-Bypass: Michael Matloob 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Knyszek 
---
 src/runtime/pprof/pprof_test.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/runtime/pprof/pprof_test.go b/src/runtime/pprof/pprof_test.go
index 6e6f4313a83dfa..23d3cf585e59f1 100644
--- a/src/runtime/pprof/pprof_test.go
+++ b/src/runtime/pprof/pprof_test.go
@@ -2549,6 +2549,9 @@ func TestProfilerStackDepth(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.profiler, func(t *testing.T) {
+			if test.profiler == "heap" {
+				testenv.SkipFlaky(t, 74029)
+			}
 			var buf bytes.Buffer
 			if err := Lookup(test.profiler).WriteTo(&buf, 0); err != nil {
 				t.Fatalf("failed to write heap profile: %v", err)

From 5b29875c8eb1002c4509eb9ebd9a4d32cfd7d494 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 20 Aug 2025 21:59:08 -0400
Subject: [PATCH 148/229] cmd/go: inject State parameter into `run.runRun`

This command modifies the call tree starting at `run.runRun` to inject
a `State` parameter to every function that is currently using the
global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/run
rf 'inject modload.LoaderState runRun'
cd ..
./rf-cleanup.zsh

Change-Id: I337323c087ed4e43af28973fad27152791eefbc2
Reviewed-on: https://go-review.googlesource.com/c/go/+/698063
TryBot-Bypass: Ian Alexander 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/bug/bug.go                |   3 +-
 src/cmd/go/internal/clean/clean.go            |   6 +-
 src/cmd/go/internal/envcmd/env.go             |  12 +-
 src/cmd/go/internal/fmtcmd/fmt.go             |   6 +-
 src/cmd/go/internal/generate/generate.go      |   6 +-
 src/cmd/go/internal/list/list.go              |  18 +-
 src/cmd/go/internal/load/flag.go              |   3 +-
 src/cmd/go/internal/load/godebug.go           |   8 +-
 src/cmd/go/internal/load/pkg.go               | 118 +++---
 src/cmd/go/internal/load/search.go            |  10 +-
 src/cmd/go/internal/load/test.go              |  11 +-
 src/cmd/go/internal/modcmd/download.go        |  18 +-
 src/cmd/go/internal/modcmd/graph.go           |   2 +-
 src/cmd/go/internal/modcmd/tidy.go            |   2 +-
 src/cmd/go/internal/modcmd/vendor.go          |  22 +-
 src/cmd/go/internal/modcmd/verify.go          |   2 +-
 src/cmd/go/internal/modcmd/why.go             |   8 +-
 .../modfetch/zip_sum_test/zip_sum_test.go     |   2 +-
 src/cmd/go/internal/modget/get.go             |  46 +--
 src/cmd/go/internal/modget/query.go           |   2 +-
 src/cmd/go/internal/modload/build.go          |  56 +--
 src/cmd/go/internal/modload/buildlist.go      | 200 +++++-----
 src/cmd/go/internal/modload/edit.go           |  30 +-
 src/cmd/go/internal/modload/import.go         |  68 ++--
 src/cmd/go/internal/modload/import_test.go    |   4 +-
 src/cmd/go/internal/modload/init.go           | 342 +++++++++---------
 src/cmd/go/internal/modload/list.go           |  32 +-
 src/cmd/go/internal/modload/load.go           | 268 +++++++-------
 src/cmd/go/internal/modload/modfile.go        | 102 +++---
 src/cmd/go/internal/modload/mvs.go            |  14 +-
 src/cmd/go/internal/modload/query.go          |  72 ++--
 src/cmd/go/internal/modload/query_test.go     |   2 +-
 src/cmd/go/internal/modload/search.go         |  44 +--
 src/cmd/go/internal/modload/vendor.go         |  24 +-
 src/cmd/go/internal/run/run.go                |  18 +-
 .../internal/telemetrystats/telemetrystats.go |   2 +-
 src/cmd/go/internal/test/test.go              |  16 +-
 src/cmd/go/internal/tool/tool.go              |  14 +-
 src/cmd/go/internal/toolchain/select.go       |   8 +-
 src/cmd/go/internal/vet/vet.go                |   6 +-
 src/cmd/go/internal/work/action.go            |  27 +-
 src/cmd/go/internal/work/build.go             |  26 +-
 src/cmd/go/internal/work/exec.go              |  16 +-
 src/cmd/go/internal/work/init.go              |   4 +-
 src/cmd/go/internal/workcmd/edit.go           |   4 +-
 src/cmd/go/internal/workcmd/init.go           |   4 +-
 src/cmd/go/internal/workcmd/sync.go           |  14 +-
 src/cmd/go/internal/workcmd/use.go            |   4 +-
 src/cmd/go/internal/workcmd/vendor.go         |   4 +-
 49 files changed, 867 insertions(+), 863 deletions(-)

diff --git a/src/cmd/go/internal/bug/bug.go b/src/cmd/go/internal/bug/bug.go
index 4ff45d2d888c96..4e9ae1e9b499ca 100644
--- a/src/cmd/go/internal/bug/bug.go
+++ b/src/cmd/go/internal/bug/bug.go
@@ -21,6 +21,7 @@ import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/envcmd"
+	"cmd/go/internal/modload"
 	"cmd/go/internal/web"
 	"cmd/go/internal/work"
 )
@@ -44,7 +45,7 @@ func runBug(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) > 0 {
 		base.Fatalf("go: bug takes no arguments")
 	}
-	work.BuildInit()
+	work.BuildInit(modload.LoaderState)
 
 	var buf strings.Builder
 	buf.WriteString(bugHeader)
diff --git a/src/cmd/go/internal/clean/clean.go b/src/cmd/go/internal/clean/clean.go
index c6f311e0263af8..1c05977de554f8 100644
--- a/src/cmd/go/internal/clean/clean.go
+++ b/src/cmd/go/internal/clean/clean.go
@@ -120,7 +120,7 @@ func init() {
 }
 
 func runClean(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 	if len(args) > 0 {
 		cacheFlag := ""
 		switch {
@@ -142,13 +142,13 @@ func runClean(ctx context.Context, cmd *base.Command, args []string) {
 	// either the flags and arguments explicitly imply a package,
 	// or no other target (such as a cache) was requested to be cleaned.
 	cleanPkg := len(args) > 0 || cleanI || cleanR
-	if (!modload.Enabled() || modload.HasModRoot()) &&
+	if (!modload.Enabled(modload.LoaderState) || modload.HasModRoot(modload.LoaderState)) &&
 		!cleanCache && !cleanModcache && !cleanTestcache && !cleanFuzzcache {
 		cleanPkg = true
 	}
 
 	if cleanPkg {
-		for _, pkg := range load.PackagesAndErrors(ctx, load.PackageOpts{}, args) {
+		for _, pkg := range load.PackagesAndErrors(modload.LoaderState, ctx, load.PackageOpts{}, args) {
 			clean(pkg)
 		}
 	}
diff --git a/src/cmd/go/internal/envcmd/env.go b/src/cmd/go/internal/envcmd/env.go
index 6ad6954dd52125..13708ae170c1d8 100644
--- a/src/cmd/go/internal/envcmd/env.go
+++ b/src/cmd/go/internal/envcmd/env.go
@@ -191,14 +191,14 @@ func findEnv(env []cfg.EnvVar, name string) string {
 // ExtraEnvVars returns environment variables that should not leak into child processes.
 func ExtraEnvVars() []cfg.EnvVar {
 	gomod := ""
-	modload.Init()
-	if modload.HasModRoot() {
+	modload.Init(modload.LoaderState)
+	if modload.HasModRoot(modload.LoaderState) {
 		gomod = modload.ModFilePath()
-	} else if modload.Enabled() {
+	} else if modload.Enabled(modload.LoaderState) {
 		gomod = os.DevNull
 	}
-	modload.InitWorkfile()
-	gowork := modload.WorkFilePath()
+	modload.InitWorkfile(modload.LoaderState)
+	gowork := modload.WorkFilePath(modload.LoaderState)
 	// As a special case, if a user set off explicitly, report that in GOWORK.
 	if cfg.Getenv("GOWORK") == "off" {
 		gowork = "off"
@@ -336,7 +336,7 @@ func runEnv(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	}
 	if needCostly {
-		work.BuildInit()
+		work.BuildInit(modload.LoaderState)
 		env = append(env, ExtraEnvVarsCostly()...)
 	}
 
diff --git a/src/cmd/go/internal/fmtcmd/fmt.go b/src/cmd/go/internal/fmtcmd/fmt.go
index 83fba9661a66fc..a42e7753050356 100644
--- a/src/cmd/go/internal/fmtcmd/fmt.go
+++ b/src/cmd/go/internal/fmtcmd/fmt.go
@@ -59,8 +59,8 @@ func runFmt(ctx context.Context, cmd *base.Command, args []string) {
 	baseGofmtArgs := len(gofmtArgs)
 	baseGofmtArgLen := gofmtArgLen
 
-	for _, pkg := range load.PackagesAndErrors(ctx, load.PackageOpts{}, args) {
-		if modload.Enabled() && pkg.Module != nil && !pkg.Module.Main {
+	for _, pkg := range load.PackagesAndErrors(modload.LoaderState, ctx, load.PackageOpts{}, args) {
+		if modload.Enabled(modload.LoaderState) && pkg.Module != nil && !pkg.Module.Main {
 			if !printed {
 				fmt.Fprintf(os.Stderr, "go: not formatting packages in dependency modules\n")
 				printed = true
@@ -70,7 +70,7 @@ func runFmt(ctx context.Context, cmd *base.Command, args []string) {
 		if pkg.Error != nil {
 			if _, ok := errors.AsType[*load.NoGoError](pkg.Error); ok {
 				// Skip this error, as we will format all files regardless.
-			} else if  _, ok := errors.AsType[*load.EmbedError](pkg.Error); ok && len(pkg.InternalAllGoFiles()) > 0 {
+			} else if _, ok := errors.AsType[*load.EmbedError](pkg.Error); ok && len(pkg.InternalAllGoFiles()) > 0 {
 				// Skip this error, as we will format all files regardless.
 			} else {
 				base.Errorf("%v", pkg.Error)
diff --git a/src/cmd/go/internal/generate/generate.go b/src/cmd/go/internal/generate/generate.go
index 0f4b4a972e9107..4250916b8d09d6 100644
--- a/src/cmd/go/internal/generate/generate.go
+++ b/src/cmd/go/internal/generate/generate.go
@@ -182,7 +182,7 @@ func init() {
 }
 
 func runGenerate(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 
 	if generateRunFlag != "" {
 		var err error
@@ -204,8 +204,8 @@ func runGenerate(ctx context.Context, cmd *base.Command, args []string) {
 	// Even if the arguments are .go files, this loop suffices.
 	printed := false
 	pkgOpts := load.PackageOpts{IgnoreImports: true}
-	for _, pkg := range load.PackagesAndErrors(ctx, pkgOpts, args) {
-		if modload.Enabled() && pkg.Module != nil && !pkg.Module.Main {
+	for _, pkg := range load.PackagesAndErrors(modload.LoaderState, ctx, pkgOpts, args) {
+		if modload.Enabled(modload.LoaderState) && pkg.Module != nil && !pkg.Module.Main {
 			if !printed {
 				fmt.Fprintf(os.Stderr, "go: not generating in packages in dependency modules\n")
 				printed = true
diff --git a/src/cmd/go/internal/list/list.go b/src/cmd/go/internal/list/list.go
index bee7dc8053ee6f..0bf86ae004a26e 100644
--- a/src/cmd/go/internal/list/list.go
+++ b/src/cmd/go/internal/list/list.go
@@ -419,7 +419,7 @@ func (v *jsonFlag) needAny(fields ...string) bool {
 var nl = []byte{'\n'}
 
 func runList(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 
 	if *listFmt != "" && listJson {
 		base.Fatalf("go list -f cannot be used with -json")
@@ -427,11 +427,11 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 	if *listReuse != "" && !*listM {
 		base.Fatalf("go list -reuse cannot be used without -m")
 	}
-	if *listReuse != "" && modload.HasModRoot() {
+	if *listReuse != "" && modload.HasModRoot(modload.LoaderState) {
 		base.Fatalf("go list -reuse cannot be used inside a module")
 	}
 
-	work.BuildInit()
+	work.BuildInit(modload.LoaderState)
 	out := newTrackingWriter(os.Stdout)
 	defer out.w.Flush()
 
@@ -496,12 +496,12 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	}
 
-	modload.Init()
+	modload.Init(modload.LoaderState)
 	if *listRetracted {
 		if cfg.BuildMod == "vendor" {
 			base.Fatalf("go list -retracted cannot be used when vendoring is enabled")
 		}
-		if !modload.Enabled() {
+		if !modload.Enabled(modload.LoaderState) {
 			base.Fatalf("go list -retracted can only be used in module-aware mode")
 		}
 	}
@@ -525,11 +525,11 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 			base.Fatalf("go list -test cannot be used with -m")
 		}
 
-		if modload.Init(); !modload.Enabled() {
+		if modload.Init(modload.LoaderState); !modload.Enabled(modload.LoaderState) {
 			base.Fatalf("go: list -m cannot be used with GO111MODULE=off")
 		}
 
-		modload.LoadModFile(ctx) // Sets cfg.BuildMod as a side-effect.
+		modload.LoadModFile(modload.LoaderState, ctx) // Sets cfg.BuildMod as a side-effect.
 		if cfg.BuildMod == "vendor" {
 			const actionDisabledFormat = "go: can't %s using the vendor directory\n\t(Use -mod=mod or -mod=readonly to bypass.)"
 
@@ -613,7 +613,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		SuppressBuildInfo:  !*listExport && !listJsonFields.needAny("Stale", "StaleReason"),
 		SuppressEmbedFiles: !*listExport && !listJsonFields.needAny("EmbedFiles", "TestEmbedFiles", "XTestEmbedFiles"),
 	}
-	pkgs := load.PackagesAndErrors(ctx, pkgOpts, args)
+	pkgs := load.PackagesAndErrors(modload.LoaderState, ctx, pkgOpts, args)
 	if !*listE {
 		w := 0
 		for _, pkg := range pkgs {
@@ -727,7 +727,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		b.NeedExport = *listExport
 		b.NeedCompiledGoFiles = *listCompiled
 		if cfg.BuildCover {
-			load.PrepareForCoverageBuild(pkgs)
+			load.PrepareForCoverageBuild(modload.LoaderState, pkgs)
 		}
 		a := &work.Action{}
 		// TODO: Use pkgsFilter?
diff --git a/src/cmd/go/internal/load/flag.go b/src/cmd/go/internal/load/flag.go
index 55bdab013505ab..86a922bc103a82 100644
--- a/src/cmd/go/internal/load/flag.go
+++ b/src/cmd/go/internal/load/flag.go
@@ -6,6 +6,7 @@ package load
 
 import (
 	"cmd/go/internal/base"
+	"cmd/go/internal/modload"
 	"cmd/internal/quoted"
 	"fmt"
 	"strings"
@@ -63,7 +64,7 @@ func (f *PerPackageFlag) set(v, cwd string) error {
 			return fmt.Errorf("parameter may not start with quote character %c", v[0])
 		}
 		pattern := strings.TrimSpace(v[:i])
-		match = MatchPackage(pattern, cwd)
+		match = MatchPackage(modload.LoaderState, pattern, cwd)
 		v = v[i+1:]
 	}
 	flags, err := quoted.Split(v)
diff --git a/src/cmd/go/internal/load/godebug.go b/src/cmd/go/internal/load/godebug.go
index c795d42f117f0e..817cc4faebf7b4 100644
--- a/src/cmd/go/internal/load/godebug.go
+++ b/src/cmd/go/internal/load/godebug.go
@@ -45,12 +45,12 @@ func ParseGoDebug(text string) (key, value string, err error) {
 // defaultGODEBUG returns the default GODEBUG setting for the main package p.
 // When building a test binary, directives, testDirectives, and xtestDirectives
 // list additional directives from the package under test.
-func defaultGODEBUG(p *Package, directives, testDirectives, xtestDirectives []build.Directive) string {
+func defaultGODEBUG(loaderstate *modload.State, p *Package, directives, testDirectives, xtestDirectives []build.Directive) string {
 	if p.Name != "main" {
 		return ""
 	}
-	goVersion := modload.LoaderState.MainModules.GoVersion()
-	if modload.LoaderState.RootMode == modload.NoRoot && p.Module != nil {
+	goVersion := loaderstate.MainModules.GoVersion(loaderstate)
+	if loaderstate.RootMode == modload.NoRoot && p.Module != nil {
 		// This is go install pkg@version or go run pkg@version.
 		// Use the Go version from the package.
 		// If there isn't one, then assume Go 1.20,
@@ -73,7 +73,7 @@ func defaultGODEBUG(p *Package, directives, testDirectives, xtestDirectives []bu
 	}
 
 	// Add directives from main module go.mod.
-	for _, g := range modload.LoaderState.MainModules.Godebugs() {
+	for _, g := range loaderstate.MainModules.Godebugs(loaderstate) {
 		if m == nil {
 			m = make(map[string]string)
 		}
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index a894affc844066..cfaece2072dbb9 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -686,8 +686,8 @@ const (
 )
 
 // LoadPackage does Load import, but without a parent package load context
-func LoadPackage(ctx context.Context, opts PackageOpts, path, srcDir string, stk *ImportStack, importPos []token.Position, mode int) *Package {
-	p, err := loadImport(ctx, opts, nil, path, srcDir, nil, stk, importPos, mode)
+func LoadPackage(loaderstate *modload.State, ctx context.Context, opts PackageOpts, path, srcDir string, stk *ImportStack, importPos []token.Position, mode int) *Package {
+	p, err := loadImport(loaderstate, ctx, opts, nil, path, srcDir, nil, stk, importPos, mode)
 	if err != nil {
 		base.Fatalf("internal error: loadImport of %q with nil parent returned an error", path)
 	}
@@ -703,7 +703,7 @@ func LoadPackage(ctx context.Context, opts PackageOpts, path, srcDir string, stk
 // The returned PackageError, if any, describes why parent is not allowed
 // to import the named package, with the error referring to importPos.
 // The PackageError can only be non-nil when parent is not nil.
-func loadImport(ctx context.Context, opts PackageOpts, pre *preload, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) (*Package, *PackageError) {
+func loadImport(loaderstate *modload.State, ctx context.Context, opts PackageOpts, pre *preload, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) (*Package, *PackageError) {
 	ctx, span := trace.StartSpan(ctx, "modload.loadImport "+path)
 	defer span.Done()
 
@@ -718,9 +718,9 @@ func loadImport(ctx context.Context, opts PackageOpts, pre *preload, path, srcDi
 		parentRoot = parent.Root
 		parentIsStd = parent.Standard
 	}
-	bp, loaded, err := loadPackageData(ctx, path, parentPath, srcDir, parentRoot, parentIsStd, mode)
+	bp, loaded, err := loadPackageData(loaderstate, ctx, path, parentPath, srcDir, parentRoot, parentIsStd, mode)
 	if loaded && pre != nil && !opts.IgnoreImports {
-		pre.preloadImports(ctx, opts, bp.Imports, bp)
+		pre.preloadImports(loaderstate, ctx, opts, bp.Imports, bp)
 	}
 	if bp == nil {
 		p := &Package{
@@ -771,7 +771,7 @@ func loadImport(ctx context.Context, opts PackageOpts, pre *preload, path, srcDi
 		// Load package.
 		// loadPackageData may return bp != nil even if an error occurs,
 		// in order to return partial information.
-		p.load(ctx, opts, path, stk, importPos, bp, err)
+		p.load(loaderstate, ctx, opts, path, stk, importPos, bp, err)
 
 		if !cfg.ModulesEnabled && path != cleanImport(path) {
 			p.Error = &PackageError{
@@ -784,7 +784,7 @@ func loadImport(ctx context.Context, opts PackageOpts, pre *preload, path, srcDi
 	}
 
 	// Checked on every import because the rules depend on the code doing the importing.
-	if perr := disallowInternal(ctx, srcDir, parent, parentPath, p, stk); perr != nil {
+	if perr := disallowInternal(loaderstate, ctx, srcDir, parent, parentPath, p, stk); perr != nil {
 		perr.setPos(importPos)
 		return p, perr
 	}
@@ -838,7 +838,7 @@ func extractFirstImport(importPos []token.Position) *token.Position {
 //
 // loadPackageData returns a boolean, loaded, which is true if this is the
 // first time the package was loaded. Callers may preload imports in this case.
-func loadPackageData(ctx context.Context, path, parentPath, parentDir, parentRoot string, parentIsStd bool, mode int) (bp *build.Package, loaded bool, err error) {
+func loadPackageData(loaderstate *modload.State, ctx context.Context, path, parentPath, parentDir, parentRoot string, parentIsStd bool, mode int) (bp *build.Package, loaded bool, err error) {
 	ctx, span := trace.StartSpan(ctx, "load.loadPackageData "+path)
 	defer span.Done()
 
@@ -883,7 +883,7 @@ func loadPackageData(ctx context.Context, path, parentPath, parentDir, parentRoo
 			r.path = newPath
 			r.dir = dir
 		} else if cfg.ModulesEnabled {
-			r.dir, r.path, r.err = modload.Lookup(parentPath, parentIsStd, path)
+			r.dir, r.path, r.err = modload.Lookup(loaderstate, parentPath, parentIsStd, path)
 		} else if build.IsLocalImport(path) {
 			r.dir = filepath.Join(parentDir, path)
 			r.path = dirToImportPath(r.dir)
@@ -892,7 +892,7 @@ func loadPackageData(ctx context.Context, path, parentPath, parentDir, parentRoo
 			// find out the key to use in packageCache without the
 			// overhead of repeated calls to buildContext.Import.
 			// The code is also needed in a few other places anyway.
-			r.path = resolveImportPath(path, parentPath, parentDir, parentRoot, parentIsStd)
+			r.path = resolveImportPath(loaderstate, path, parentPath, parentDir, parentRoot, parentIsStd)
 		} else if mode&ResolveModule != 0 {
 			r.path = moduleImportPath(path, parentPath, parentDir, parentRoot)
 		}
@@ -921,7 +921,7 @@ func loadPackageData(ctx context.Context, path, parentPath, parentDir, parentRoo
 			} else {
 				buildContext.GOPATH = "" // Clear GOPATH so packages are imported as pure module packages
 			}
-			modroot := modload.PackageModRoot(ctx, r.path)
+			modroot := modload.PackageModRoot(loaderstate, ctx, r.path)
 			if modroot == "" && str.HasPathPrefix(r.dir, cfg.GOROOTsrc) {
 				modroot = cfg.GOROOTsrc
 				gorootSrcCmd := filepath.Join(cfg.GOROOTsrc, "cmd")
@@ -942,7 +942,7 @@ func loadPackageData(ctx context.Context, path, parentPath, parentDir, parentRoo
 			if cfg.ModulesEnabled {
 				// Override data.p.Root, since ImportDir sets it to $GOPATH, if
 				// the module is inside $GOPATH/src.
-				if info := modload.PackageModuleInfo(ctx, path); info != nil {
+				if info := modload.PackageModuleInfo(loaderstate, ctx, path); info != nil {
 					data.p.Root = info.Dir
 				}
 			}
@@ -989,7 +989,7 @@ func loadPackageData(ctx context.Context, path, parentPath, parentDir, parentRoo
 			if cfg.GOBIN != "" {
 				data.p.BinDir = cfg.GOBIN
 			} else if cfg.ModulesEnabled {
-				data.p.BinDir = modload.BinDir()
+				data.p.BinDir = modload.BinDir(loaderstate)
 			}
 		}
 
@@ -1068,7 +1068,7 @@ func newPreload() *preload {
 // preloadMatches loads data for package paths matched by patterns.
 // When preloadMatches returns, some packages may not be loaded yet, but
 // loadPackageData and loadImport are always safe to call.
-func (pre *preload) preloadMatches(ctx context.Context, opts PackageOpts, matches []*search.Match) {
+func (pre *preload) preloadMatches(loaderstate *modload.State, ctx context.Context, opts PackageOpts, matches []*search.Match) {
 	for _, m := range matches {
 		for _, pkg := range m.Pkgs {
 			select {
@@ -1077,10 +1077,10 @@ func (pre *preload) preloadMatches(ctx context.Context, opts PackageOpts, matche
 			case pre.sema <- struct{}{}:
 				go func(pkg string) {
 					mode := 0 // don't use vendoring or module import resolution
-					bp, loaded, err := loadPackageData(ctx, pkg, "", base.Cwd(), "", false, mode)
+					bp, loaded, err := loadPackageData(loaderstate, ctx, pkg, "", base.Cwd(), "", false, mode)
 					<-pre.sema
 					if bp != nil && loaded && err == nil && !opts.IgnoreImports {
-						pre.preloadImports(ctx, opts, bp.Imports, bp)
+						pre.preloadImports(loaderstate, ctx, opts, bp.Imports, bp)
 					}
 				}(pkg)
 			}
@@ -1091,7 +1091,7 @@ func (pre *preload) preloadMatches(ctx context.Context, opts PackageOpts, matche
 // preloadImports queues a list of imports for preloading.
 // When preloadImports returns, some packages may not be loaded yet,
 // but loadPackageData and loadImport are always safe to call.
-func (pre *preload) preloadImports(ctx context.Context, opts PackageOpts, imports []string, parent *build.Package) {
+func (pre *preload) preloadImports(loaderstate *modload.State, ctx context.Context, opts PackageOpts, imports []string, parent *build.Package) {
 	parentIsStd := parent.Goroot && parent.ImportPath != "" && search.IsStandardImportPath(parent.ImportPath)
 	for _, path := range imports {
 		if path == "C" || path == "unsafe" {
@@ -1102,10 +1102,10 @@ func (pre *preload) preloadImports(ctx context.Context, opts PackageOpts, import
 			return
 		case pre.sema <- struct{}{}:
 			go func(path string) {
-				bp, loaded, err := loadPackageData(ctx, path, parent.ImportPath, parent.Dir, parent.Root, parentIsStd, ResolveImport)
+				bp, loaded, err := loadPackageData(loaderstate, ctx, path, parent.ImportPath, parent.Dir, parent.Root, parentIsStd, ResolveImport)
 				<-pre.sema
 				if bp != nil && loaded && err == nil && !opts.IgnoreImports {
-					pre.preloadImports(ctx, opts, bp.Imports, bp)
+					pre.preloadImports(loaderstate, ctx, opts, bp.Imports, bp)
 				}
 			}(path)
 		}
@@ -1160,12 +1160,12 @@ func ResolveImportPath(parent *Package, path string) (found string) {
 		parentRoot = parent.Root
 		parentIsStd = parent.Standard
 	}
-	return resolveImportPath(path, parentPath, parentDir, parentRoot, parentIsStd)
+	return resolveImportPath(modload.LoaderState, path, parentPath, parentDir, parentRoot, parentIsStd)
 }
 
-func resolveImportPath(path, parentPath, parentDir, parentRoot string, parentIsStd bool) (found string) {
+func resolveImportPath(loaderstate *modload.State, path, parentPath, parentDir, parentRoot string, parentIsStd bool) (found string) {
 	if cfg.ModulesEnabled {
-		if _, p, e := modload.Lookup(parentPath, parentIsStd, path); e == nil {
+		if _, p, e := modload.Lookup(loaderstate, parentPath, parentIsStd, path); e == nil {
 			return p
 		}
 		return path
@@ -1463,7 +1463,7 @@ func reusePackage(p *Package, stk *ImportStack) *Package {
 // is allowed to import p.
 // If the import is allowed, disallowInternal returns the original package p.
 // If not, it returns a new package containing just an appropriate error.
-func disallowInternal(ctx context.Context, srcDir string, importer *Package, importerPath string, p *Package, stk *ImportStack) *PackageError {
+func disallowInternal(loaderstate *modload.State, ctx context.Context, srcDir string, importer *Package, importerPath string, p *Package, stk *ImportStack) *PackageError {
 	// golang.org/s/go14internal:
 	// An import of a path containing the element “internal”
 	// is disallowed if the importing code is outside the tree
@@ -1552,7 +1552,7 @@ func disallowInternal(ctx context.Context, srcDir string, importer *Package, imp
 			// directory containing them.
 			// If the directory is outside the main modules, this will resolve to ".",
 			// which is not a prefix of any valid module.
-			importerPath, _ = modload.LoaderState.MainModules.DirImportPath(ctx, importer.Dir)
+			importerPath, _ = loaderstate.MainModules.DirImportPath(loaderstate, ctx, importer.Dir)
 		}
 		parentOfInternal := p.ImportPath[:i]
 		if str.HasPathPrefix(importerPath, parentOfInternal) {
@@ -1771,7 +1771,7 @@ func (p *Package) DefaultExecName() string {
 // load populates p using information from bp, err, which should
 // be the result of calling build.Context.Import.
 // stk contains the import stack, not including path itself.
-func (p *Package) load(ctx context.Context, opts PackageOpts, path string, stk *ImportStack, importPos []token.Position, bp *build.Package, err error) {
+func (p *Package) load(loaderstate *modload.State, ctx context.Context, opts PackageOpts, path string, stk *ImportStack, importPos []token.Position, bp *build.Package, err error) {
 	p.copyBuild(opts, bp)
 
 	// The localPrefix is the path we interpret ./ imports relative to,
@@ -1835,7 +1835,7 @@ func (p *Package) load(ctx context.Context, opts PackageOpts, path string, stk *
 			elem = full
 		}
 		if p.Internal.Build.BinDir == "" && cfg.ModulesEnabled {
-			p.Internal.Build.BinDir = modload.BinDir()
+			p.Internal.Build.BinDir = modload.BinDir(loaderstate)
 		}
 		if p.Internal.Build.BinDir != "" {
 			// Install to GOBIN or bin of GOPATH entry.
@@ -1973,9 +1973,9 @@ func (p *Package) load(ctx context.Context, opts PackageOpts, path string, stk *
 		pkgPath = "command-line-arguments"
 	}
 	if cfg.ModulesEnabled {
-		p.Module = modload.PackageModuleInfo(ctx, pkgPath)
+		p.Module = modload.PackageModuleInfo(loaderstate, ctx, pkgPath)
 	}
-	p.DefaultGODEBUG = defaultGODEBUG(p, nil, nil, nil)
+	p.DefaultGODEBUG = defaultGODEBUG(loaderstate, p, nil, nil, nil)
 
 	if !opts.SuppressEmbedFiles {
 		p.EmbedFiles, p.Internal.Embed, err = resolveEmbed(p.Dir, p.EmbedPatterns)
@@ -2026,7 +2026,7 @@ func (p *Package) load(ctx context.Context, opts PackageOpts, path string, stk *
 		if path == "C" {
 			continue
 		}
-		p1, err := loadImport(ctx, opts, nil, path, p.Dir, p, stk, p.Internal.Build.ImportPos[path], ResolveImport)
+		p1, err := loadImport(loaderstate, ctx, opts, nil, path, p.Dir, p, stk, p.Internal.Build.ImportPos[path], ResolveImport)
 		if err != nil && p.Error == nil {
 			p.Error = err
 			p.Incomplete = true
@@ -2813,7 +2813,7 @@ func TestPackageList(ctx context.Context, opts PackageOpts, roots []*Package) []
 	}
 	walkTest := func(root *Package, path string) {
 		var stk ImportStack
-		p1, err := loadImport(ctx, opts, nil, path, root.Dir, root, &stk, root.Internal.Build.TestImportPos[path], ResolveImport)
+		p1, err := loadImport(modload.LoaderState, ctx, opts, nil, path, root.Dir, root, &stk, root.Internal.Build.TestImportPos[path], ResolveImport)
 		if err != nil && root.Error == nil {
 			// Assign error importing the package to the importer.
 			root.Error = err
@@ -2840,16 +2840,16 @@ func TestPackageList(ctx context.Context, opts PackageOpts, roots []*Package) []
 // dependencies (like sync/atomic for coverage).
 // TODO(jayconrod): delete this function and set flags automatically
 // in LoadImport instead.
-func LoadImportWithFlags(path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) (*Package, *PackageError) {
-	p, err := loadImport(context.TODO(), PackageOpts{}, nil, path, srcDir, parent, stk, importPos, mode)
+func LoadImportWithFlags(loaderstate *modload.State, path, srcDir string, parent *Package, stk *ImportStack, importPos []token.Position, mode int) (*Package, *PackageError) {
+	p, err := loadImport(loaderstate, context.TODO(), PackageOpts{}, nil, path, srcDir, parent, stk, importPos, mode)
 	setToolFlags(p)
 	return p, err
 }
 
 // LoadPackageWithFlags is the same as LoadImportWithFlags but without a parent.
 // It's then guaranteed to not return an error
-func LoadPackageWithFlags(path, srcDir string, stk *ImportStack, importPos []token.Position, mode int) *Package {
-	p := LoadPackage(context.TODO(), PackageOpts{}, path, srcDir, stk, importPos, mode)
+func LoadPackageWithFlags(loaderstate *modload.State, path, srcDir string, stk *ImportStack, importPos []token.Position, mode int) *Package {
+	p := LoadPackage(loaderstate, context.TODO(), PackageOpts{}, path, srcDir, stk, importPos, mode)
 	setToolFlags(p)
 	return p
 }
@@ -2899,7 +2899,7 @@ type PackageOpts struct {
 //
 // To obtain a flat list of packages, use PackageList.
 // To report errors loading packages, use ReportPackageErrors.
-func PackagesAndErrors(ctx context.Context, opts PackageOpts, patterns []string) []*Package {
+func PackagesAndErrors(loaderstate *modload.State, ctx context.Context, opts PackageOpts, patterns []string) []*Package {
 	ctx, span := trace.StartSpan(ctx, "load.PackagesAndErrors")
 	defer span.Done()
 
@@ -2911,7 +2911,7 @@ func PackagesAndErrors(ctx context.Context, opts PackageOpts, patterns []string)
 			// We need to test whether the path is an actual Go file and not a
 			// package path or pattern ending in '.go' (see golang.org/issue/34653).
 			if fi, err := fsys.Stat(p); err == nil && !fi.IsDir() {
-				pkgs := []*Package{GoFilesPackage(ctx, opts, patterns)}
+				pkgs := []*Package{GoFilesPackage(loaderstate, ctx, opts, patterns)}
 				setPGOProfilePath(pkgs)
 				return pkgs
 			}
@@ -2919,13 +2919,13 @@ func PackagesAndErrors(ctx context.Context, opts PackageOpts, patterns []string)
 	}
 
 	var matches []*search.Match
-	if modload.Init(); cfg.ModulesEnabled {
+	if modload.Init(loaderstate); cfg.ModulesEnabled {
 		modOpts := modload.PackageOpts{
 			ResolveMissingImports: true,
 			LoadTests:             opts.ModResolveTests,
 			SilencePackageErrors:  true,
 		}
-		matches, _ = modload.LoadPackages(ctx, modOpts, patterns...)
+		matches, _ = modload.LoadPackages(loaderstate, ctx, modOpts, patterns...)
 	} else {
 		matches = search.ImportPaths(patterns)
 	}
@@ -2938,7 +2938,7 @@ func PackagesAndErrors(ctx context.Context, opts PackageOpts, patterns []string)
 
 	pre := newPreload()
 	defer pre.flush()
-	pre.preloadMatches(ctx, opts, matches)
+	pre.preloadMatches(loaderstate, ctx, opts, matches)
 
 	for _, m := range matches {
 		for _, pkg := range m.Pkgs {
@@ -2952,7 +2952,7 @@ func PackagesAndErrors(ctx context.Context, opts PackageOpts, patterns []string)
 				// a literal and also a non-literal pattern.
 				mode |= cmdlinePkgLiteral
 			}
-			p, perr := loadImport(ctx, opts, pre, pkg, base.Cwd(), nil, &stk, nil, mode)
+			p, perr := loadImport(loaderstate, ctx, opts, pre, pkg, base.Cwd(), nil, &stk, nil, mode)
 			if perr != nil {
 				base.Fatalf("internal error: loadImport of %q with nil parent returned an error", pkg)
 			}
@@ -3243,8 +3243,8 @@ func setToolFlags(pkgs ...*Package) {
 // GoFilesPackage creates a package for building a collection of Go files
 // (typically named on the command line). The target is named p.a for
 // package p or named after the first Go file for package main.
-func GoFilesPackage(ctx context.Context, opts PackageOpts, gofiles []string) *Package {
-	modload.Init()
+func GoFilesPackage(loaderstate *modload.State, ctx context.Context, opts PackageOpts, gofiles []string) *Package {
+	modload.Init(loaderstate)
 
 	for _, f := range gofiles {
 		if !strings.HasSuffix(f, ".go") {
@@ -3289,7 +3289,7 @@ func GoFilesPackage(ctx context.Context, opts PackageOpts, gofiles []string) *Pa
 	ctxt.ReadDir = func(string) ([]fs.FileInfo, error) { return dirent, nil }
 
 	if cfg.ModulesEnabled {
-		modload.ImportFromFiles(ctx, gofiles)
+		modload.ImportFromFiles(loaderstate, ctx, gofiles)
 	}
 
 	var err error
@@ -3305,7 +3305,7 @@ func GoFilesPackage(ctx context.Context, opts PackageOpts, gofiles []string) *Pa
 	pkg := new(Package)
 	pkg.Internal.Local = true
 	pkg.Internal.CmdlineFiles = true
-	pkg.load(ctx, opts, "command-line-arguments", &stk, nil, bp, err)
+	pkg.load(loaderstate, ctx, opts, "command-line-arguments", &stk, nil, bp, err)
 	if !cfg.ModulesEnabled {
 		pkg.Internal.LocalPrefix = dirToImportPath(dir)
 	}
@@ -3319,7 +3319,7 @@ func GoFilesPackage(ctx context.Context, opts PackageOpts, gofiles []string) *Pa
 		if cfg.GOBIN != "" {
 			pkg.Target = filepath.Join(cfg.GOBIN, exe)
 		} else if cfg.ModulesEnabled {
-			pkg.Target = filepath.Join(modload.BinDir(), exe)
+			pkg.Target = filepath.Join(modload.BinDir(loaderstate), exe)
 		}
 	}
 
@@ -3347,11 +3347,11 @@ func GoFilesPackage(ctx context.Context, opts PackageOpts, gofiles []string) *Pa
 // module, but its go.mod file (if it has one) must not contain directives that
 // would cause it to be interpreted differently if it were the main module
 // (replace, exclude).
-func PackagesAndErrorsOutsideModule(ctx context.Context, opts PackageOpts, args []string) ([]*Package, error) {
-	if !modload.LoaderState.ForceUseModules {
+func PackagesAndErrorsOutsideModule(loaderstate *modload.State, ctx context.Context, opts PackageOpts, args []string) ([]*Package, error) {
+	if !loaderstate.ForceUseModules {
 		panic("modload.ForceUseModules must be true")
 	}
-	if modload.LoaderState.RootMode != modload.NoRoot {
+	if loaderstate.RootMode != modload.NoRoot {
 		panic("modload.RootMode must be NoRoot")
 	}
 
@@ -3404,12 +3404,12 @@ func PackagesAndErrorsOutsideModule(ctx context.Context, opts PackageOpts, args
 		allowed = nil
 	}
 	noneSelected := func(path string) (version string) { return "none" }
-	qrs, err := modload.QueryPackages(ctx, patterns[0], version, noneSelected, allowed)
+	qrs, err := modload.QueryPackages(loaderstate, ctx, patterns[0], version, noneSelected, allowed)
 	if err != nil {
 		return nil, fmt.Errorf("%s: %w", args[0], err)
 	}
 	rootMod := qrs[0].Mod
-	deprecation, err := modload.CheckDeprecation(ctx, rootMod)
+	deprecation, err := modload.CheckDeprecation(loaderstate, ctx, rootMod)
 	if err != nil {
 		return nil, fmt.Errorf("%s: %w", args[0], err)
 	}
@@ -3438,12 +3438,12 @@ func PackagesAndErrorsOutsideModule(ctx context.Context, opts PackageOpts, args
 	// Since we are in NoRoot mode, the build list initially contains only
 	// the dummy command-line-arguments module. Add a requirement on the
 	// module that provides the packages named on the command line.
-	if _, err := modload.EditBuildList(ctx, nil, []module.Version{rootMod}); err != nil {
+	if _, err := modload.EditBuildList(loaderstate, ctx, nil, []module.Version{rootMod}); err != nil {
 		return nil, fmt.Errorf("%s: %w", args[0], err)
 	}
 
 	// Load packages for all arguments.
-	pkgs := PackagesAndErrors(ctx, opts, patterns)
+	pkgs := PackagesAndErrors(loaderstate, ctx, opts, patterns)
 
 	// Check that named packages are all provided by the same module.
 	for _, pkg := range pkgs {
@@ -3471,14 +3471,14 @@ func PackagesAndErrorsOutsideModule(ctx context.Context, opts PackageOpts, args
 }
 
 // EnsureImport ensures that package p imports the named package.
-func EnsureImport(p *Package, pkg string) {
+func EnsureImport(loaderstate *modload.State, p *Package, pkg string) {
 	for _, d := range p.Internal.Imports {
 		if d.Name == pkg {
 			return
 		}
 	}
 
-	p1, err := LoadImportWithFlags(pkg, p.Dir, p, &ImportStack{}, nil, 0)
+	p1, err := LoadImportWithFlags(loaderstate, pkg, p.Dir, p, &ImportStack{}, nil, 0)
 	if err != nil {
 		base.Fatalf("load %s: %v", pkg, err)
 	}
@@ -3494,7 +3494,7 @@ func EnsureImport(p *Package, pkg string) {
 // "go test -cover"). It walks through the packages being built (and
 // dependencies) and marks them for coverage instrumentation when
 // appropriate, and possibly adding additional deps where needed.
-func PrepareForCoverageBuild(pkgs []*Package) {
+func PrepareForCoverageBuild(loaderstate *modload.State, pkgs []*Package) {
 	var match []func(*Package) bool
 
 	matchMainModAndCommandLine := func(p *Package) bool {
@@ -3507,7 +3507,7 @@ func PrepareForCoverageBuild(pkgs []*Package) {
 		// the specific packages selected by the user-specified pattern(s).
 		match = make([]func(*Package) bool, len(cfg.BuildCoverPkg))
 		for i := range cfg.BuildCoverPkg {
-			match[i] = MatchPackage(cfg.BuildCoverPkg[i], base.Cwd())
+			match[i] = MatchPackage(loaderstate, cfg.BuildCoverPkg[i], base.Cwd())
 		}
 	} else {
 		// Without -coverpkg, instrument only packages in the main module
@@ -3519,10 +3519,10 @@ func PrepareForCoverageBuild(pkgs []*Package) {
 	// Visit the packages being built or installed, along with all of
 	// their dependencies, and mark them to be instrumented, taking
 	// into account the matchers we've set up in the sequence above.
-	SelectCoverPackages(PackageList(pkgs), match, "build")
+	SelectCoverPackages(loaderstate, PackageList(pkgs), match, "build")
 }
 
-func SelectCoverPackages(roots []*Package, match []func(*Package) bool, op string) []*Package {
+func SelectCoverPackages(loaderstate *modload.State, roots []*Package, match []func(*Package) bool, op string) []*Package {
 	var warntag string
 	var includeMain bool
 	switch op {
@@ -3602,7 +3602,7 @@ func SelectCoverPackages(roots []*Package, match []func(*Package) bool, op strin
 
 		// Force import of sync/atomic into package if atomic mode.
 		if cfg.BuildCoverMode == "atomic" {
-			EnsureImport(p, "sync/atomic")
+			EnsureImport(loaderstate, p, "sync/atomic")
 		}
 	}
 
diff --git a/src/cmd/go/internal/load/search.go b/src/cmd/go/internal/load/search.go
index 51c8cc0932406e..09e32a4f46a69b 100644
--- a/src/cmd/go/internal/load/search.go
+++ b/src/cmd/go/internal/load/search.go
@@ -14,7 +14,7 @@ import (
 )
 
 // MatchPackage(pattern, cwd)(p) reports whether package p matches pattern in the working directory cwd.
-func MatchPackage(pattern, cwd string) func(*Package) bool {
+func MatchPackage(loaderstate *modload.State, pattern, cwd string) func(*Package) bool {
 	switch {
 	case search.IsRelativePath(pattern):
 		// Split pattern into leading pattern-free directory path
@@ -54,13 +54,13 @@ func MatchPackage(pattern, cwd string) func(*Package) bool {
 		return func(p *Package) bool { return p.Standard }
 	case pattern == "cmd":
 		return func(p *Package) bool { return p.Standard && strings.HasPrefix(p.ImportPath, "cmd/") }
-	case pattern == "tool" && modload.Enabled():
+	case pattern == "tool" && modload.Enabled(loaderstate):
 		return func(p *Package) bool {
-			return modload.LoaderState.MainModules.Tools()[p.ImportPath]
+			return loaderstate.MainModules.Tools()[p.ImportPath]
 		}
-	case pattern == "work" && modload.Enabled():
+	case pattern == "work" && modload.Enabled(loaderstate):
 		return func(p *Package) bool {
-			return p.Module != nil && modload.LoaderState.MainModules.Contains(p.Module.Path)
+			return p.Module != nil && loaderstate.MainModules.Contains(p.Module.Path)
 		}
 
 	default:
diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
index 9849ee138a5781..9019545b4b8d82 100644
--- a/src/cmd/go/internal/load/test.go
+++ b/src/cmd/go/internal/load/test.go
@@ -24,6 +24,7 @@ import (
 	"unicode/utf8"
 
 	"cmd/go/internal/fsys"
+	"cmd/go/internal/modload"
 	"cmd/go/internal/str"
 	"cmd/go/internal/trace"
 )
@@ -106,7 +107,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 	defer pre.flush()
 	allImports := append([]string{}, p.TestImports...)
 	allImports = append(allImports, p.XTestImports...)
-	pre.preloadImports(ctx, opts, allImports, p.Internal.Build)
+	pre.preloadImports(modload.LoaderState, ctx, opts, allImports, p.Internal.Build)
 
 	var ptestErr, pxtestErr *PackageError
 	var imports, ximports []*Package
@@ -116,7 +117,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 	stk.Push(ImportInfo{Pkg: p.ImportPath + " (test)"})
 	rawTestImports := str.StringList(p.TestImports)
 	for i, path := range p.TestImports {
-		p1, err := loadImport(ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.TestImportPos[path], ResolveImport)
+		p1, err := loadImport(modload.LoaderState, ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.TestImportPos[path], ResolveImport)
 		if err != nil && ptestErr == nil {
 			ptestErr = err
 			incomplete = true
@@ -145,7 +146,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 	var pxtestIncomplete bool
 	rawXTestImports := str.StringList(p.XTestImports)
 	for i, path := range p.XTestImports {
-		p1, err := loadImport(ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.XTestImportPos[path], ResolveImport)
+		p1, err := loadImport(modload.LoaderState, ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.XTestImportPos[path], ResolveImport)
 		if err != nil && pxtestErr == nil {
 			pxtestErr = err
 		}
@@ -292,7 +293,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 	}
 
 	pb := p.Internal.Build
-	pmain.DefaultGODEBUG = defaultGODEBUG(pmain, pb.Directives, pb.TestDirectives, pb.XTestDirectives)
+	pmain.DefaultGODEBUG = defaultGODEBUG(modload.LoaderState, pmain, pb.Directives, pb.TestDirectives, pb.XTestDirectives)
 	if pmain.Internal.BuildInfo == nil || pmain.DefaultGODEBUG != p.DefaultGODEBUG {
 		// Either we didn't generate build info for the package under test (because it wasn't package main), or
 		// the DefaultGODEBUG used to build the test main package is different from the DefaultGODEBUG
@@ -321,7 +322,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 		if dep == ptest.ImportPath {
 			pmain.Internal.Imports = append(pmain.Internal.Imports, ptest)
 		} else {
-			p1, err := loadImport(ctx, opts, pre, dep, "", nil, &stk, nil, 0)
+			p1, err := loadImport(modload.LoaderState, ctx, opts, pre, dep, "", nil, &stk, nil, 0)
 			if err != nil && pmain.Error == nil {
 				pmain.Error = err
 				pmain.Incomplete = true
diff --git a/src/cmd/go/internal/modcmd/download.go b/src/cmd/go/internal/modcmd/download.go
index 8df11bfa59fa43..f4ed4b45834e89 100644
--- a/src/cmd/go/internal/modcmd/download.go
+++ b/src/cmd/go/internal/modcmd/download.go
@@ -109,15 +109,15 @@ type ModuleJSON struct {
 }
 
 func runDownload(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 
 	// Check whether modules are enabled and whether we're in a module.
 	modload.LoaderState.ForceUseModules = true
 	modload.ExplicitWriteGoMod = true
 	haveExplicitArgs := len(args) > 0
 
-	if modload.HasModRoot() || modload.WorkFilePath() != "" {
-		modload.LoadModFile(ctx) // to fill MainModules
+	if modload.HasModRoot(modload.LoaderState) || modload.WorkFilePath(modload.LoaderState) != "" {
+		modload.LoadModFile(modload.LoaderState, ctx) // to fill MainModules
 
 		if haveExplicitArgs {
 			for _, mainModule := range modload.LoaderState.MainModules.Versions() {
@@ -130,7 +130,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 					}
 				}
 			}
-		} else if modload.WorkFilePath() != "" {
+		} else if modload.WorkFilePath(modload.LoaderState) != "" {
 			// TODO(#44435): Think about what the correct query is to download the
 			// right set of modules. Also see code review comment at
 			// https://go-review.googlesource.com/c/go/+/359794/comments/ce946a80_6cf53992.
@@ -169,7 +169,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	}
 
 	if len(args) == 0 {
-		if modload.HasModRoot() {
+		if modload.HasModRoot(modload.LoaderState) {
 			os.Stderr.WriteString("go: no module dependencies to download\n")
 		} else {
 			base.Errorf("go: no modules specified (see 'go help mod download')")
@@ -177,7 +177,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 		base.Exit()
 	}
 
-	if *downloadReuse != "" && modload.HasModRoot() {
+	if *downloadReuse != "" && modload.HasModRoot(modload.LoaderState) {
 		base.Fatalf("go mod download -reuse cannot be used inside a module")
 	}
 
@@ -220,7 +220,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 		// when we can.
 	}
 
-	if !haveExplicitArgs && modload.WorkFilePath() == "" {
+	if !haveExplicitArgs && modload.WorkFilePath(modload.LoaderState) == "" {
 		// 'go mod download' is sometimes run without arguments to pre-populate the
 		// module cache. In modules that aren't at go 1.17 or higher, it may fetch
 		// modules that aren't needed to build packages in the main module. This is
@@ -291,7 +291,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	// with no arguments we download the module pattern "all",
 	// which may include dependencies that are normally pruned out
 	// of the individual modules in the workspace.
-	if haveExplicitArgs || modload.WorkFilePath() != "" {
+	if haveExplicitArgs || modload.WorkFilePath(modload.LoaderState) != "" {
 		var sw toolchain.Switcher
 		// Add errors to the Switcher in deterministic order so that they will be
 		// logged deterministically.
@@ -347,7 +347,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	//
 	// Don't save sums for 'go mod download' without arguments unless we're in
 	// workspace mode; see comment above.
-	if haveExplicitArgs || modload.WorkFilePath() != "" {
+	if haveExplicitArgs || modload.WorkFilePath(modload.LoaderState) != "" {
 		if err := modload.WriteGoMod(ctx, modload.WriteOpts{}); err != nil {
 			base.Error(err)
 		}
diff --git a/src/cmd/go/internal/modcmd/graph.go b/src/cmd/go/internal/modcmd/graph.go
index 5f47260e188292..3bc6009b57b595 100644
--- a/src/cmd/go/internal/modcmd/graph.go
+++ b/src/cmd/go/internal/modcmd/graph.go
@@ -52,7 +52,7 @@ func init() {
 }
 
 func runGraph(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 
 	if len(args) > 0 {
 		base.Fatalf("go: 'go mod graph' accepts no arguments")
diff --git a/src/cmd/go/internal/modcmd/tidy.go b/src/cmd/go/internal/modcmd/tidy.go
index 0314dcef250d81..c693bd52a38af9 100644
--- a/src/cmd/go/internal/modcmd/tidy.go
+++ b/src/cmd/go/internal/modcmd/tidy.go
@@ -130,7 +130,7 @@ func runTidy(ctx context.Context, cmd *base.Command, args []string) {
 		})
 	}
 
-	modload.LoadPackages(ctx, modload.PackageOpts{
+	modload.LoadPackages(modload.LoaderState, ctx, modload.PackageOpts{
 		TidyGoVersion:            tidyGo.String(),
 		Tags:                     imports.AnyTags(),
 		Tidy:                     true,
diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index df673e885c1473..8d9672d5365523 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -66,8 +66,8 @@ func init() {
 }
 
 func runVendor(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
-	if modload.WorkFilePath() != "" {
+	modload.InitWorkfile(modload.LoaderState)
+	if modload.WorkFilePath(modload.LoaderState) != "" {
 		base.Fatalf("go: 'go mod vendor' cannot be run in workspace mode. Run 'go work vendor' to vendor the workspace or set 'GOWORK=off' to exit workspace mode.")
 	}
 	RunVendor(ctx, vendorE, vendorO, args)
@@ -88,7 +88,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 		AllowErrors:              vendorE,
 		SilenceMissingStdImports: true,
 	}
-	_, pkgs := modload.LoadPackages(ctx, loadOpts, "all")
+	_, pkgs := modload.LoadPackages(modload.LoaderState, ctx, loadOpts, "all")
 
 	var vdir string
 	switch {
@@ -97,7 +97,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 	case vendorO != "":
 		vdir = filepath.Join(base.Cwd(), vendorO)
 	default:
-		vdir = filepath.Join(modload.VendorDir())
+		vdir = filepath.Join(modload.VendorDir(modload.LoaderState))
 	}
 	if err := os.RemoveAll(vdir); err != nil {
 		base.Fatal(err)
@@ -116,8 +116,8 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 	includeAllReplacements := false
 	includeGoVersions := false
 	isExplicit := map[module.Version]bool{}
-	gv := modload.LoaderState.MainModules.GoVersion()
-	if gover.Compare(gv, "1.14") >= 0 && (modload.FindGoWork(base.Cwd()) != "" || modload.ModFile().Go != nil) {
+	gv := modload.LoaderState.MainModules.GoVersion(modload.LoaderState)
+	if gover.Compare(gv, "1.14") >= 0 && (modload.FindGoWork(modload.LoaderState, base.Cwd()) != "" || modload.ModFile().Go != nil) {
 		// If the Go version is at least 1.14, annotate all explicit 'require' and
 		// 'replace' targets found in the go.mod file so that we can perform a
 		// stronger consistency check when -mod=vendor is set.
@@ -162,7 +162,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 
 	replacementWritten := make(map[module.Version]bool)
 	for _, m := range vendorMods {
-		replacement := modload.Replacement(m)
+		replacement := modload.Replacement(modload.LoaderState, m)
 		line := moduleLine(m, replacement)
 		replacementWritten[m] = true
 		io.WriteString(w, line)
@@ -215,7 +215,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 						continue
 					}
 					replacementWritten[r.Old] = true
-					rNew := modload.Replacement(r.Old)
+					rNew := modload.Replacement(modload.LoaderState, r.Old)
 					if rNew == (module.Version{}) {
 						// There is no replacement. Don't try to write it.
 						continue
@@ -269,7 +269,7 @@ func moduleLine(m, r module.Version) string {
 }
 
 func vendorPkg(vdir, pkg string) {
-	src, realPath, _ := modload.Lookup("", false, pkg)
+	src, realPath, _ := modload.Lookup(modload.LoaderState, "", false, pkg)
 	if src == "" {
 		base.Errorf("internal error: no pkg for %s\n", pkg)
 		return
@@ -315,7 +315,7 @@ func vendorPkg(vdir, pkg string) {
 		}
 	}
 	var embedPatterns []string
-	if gover.Compare(modload.LoaderState.MainModules.GoVersion(), "1.22") >= 0 {
+	if gover.Compare(modload.LoaderState.MainModules.GoVersion(modload.LoaderState), "1.22") >= 0 {
 		embedPatterns = bp.EmbedPatterns
 	} else {
 		// Maintain the behavior of https://github.com/golang/go/issues/63473
@@ -431,7 +431,7 @@ func matchPotentialSourceFile(dir string, info fs.DirEntry) bool {
 		return false
 	}
 	if info.Name() == "go.mod" || info.Name() == "go.sum" {
-		if gv := modload.LoaderState.MainModules.GoVersion(); gover.Compare(gv, "1.17") >= 0 {
+		if gv := modload.LoaderState.MainModules.GoVersion(modload.LoaderState); gover.Compare(gv, "1.17") >= 0 {
 			// As of Go 1.17, we strip go.mod and go.sum files from dependency modules.
 			// Otherwise, 'go' commands invoked within the vendor subtree may misidentify
 			// an arbitrary directory within the vendor tree as a module root.
diff --git a/src/cmd/go/internal/modcmd/verify.go b/src/cmd/go/internal/modcmd/verify.go
index 8de444ff06ad1d..d8227bcd5455a3 100644
--- a/src/cmd/go/internal/modcmd/verify.go
+++ b/src/cmd/go/internal/modcmd/verify.go
@@ -44,7 +44,7 @@ func init() {
 }
 
 func runVerify(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 
 	if len(args) != 0 {
 		// NOTE(rsc): Could take a module pattern.
diff --git a/src/cmd/go/internal/modcmd/why.go b/src/cmd/go/internal/modcmd/why.go
index 62a5387ed8841c..b37d9fded0f47c 100644
--- a/src/cmd/go/internal/modcmd/why.go
+++ b/src/cmd/go/internal/modcmd/why.go
@@ -63,7 +63,7 @@ func init() {
 }
 
 func runWhy(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 	modload.LoaderState.ForceUseModules = true
 	modload.LoaderState.RootMode = modload.NeedRoot
 	modload.ExplicitWriteGoMod = true // don't write go.mod in ListModules
@@ -89,7 +89,7 @@ func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 		}
 
 		byModule := make(map[string][]string)
-		_, pkgs := modload.LoadPackages(ctx, loadOpts, "all")
+		_, pkgs := modload.LoadPackages(modload.LoaderState, ctx, loadOpts, "all")
 		for _, path := range pkgs {
 			m := modload.PackageModule(path)
 			if m.Path != "" {
@@ -120,9 +120,9 @@ func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	} else {
 		// Resolve to packages.
-		matches, _ := modload.LoadPackages(ctx, loadOpts, args...)
+		matches, _ := modload.LoadPackages(modload.LoaderState, ctx, loadOpts, args...)
 
-		modload.LoadPackages(ctx, loadOpts, "all") // rebuild graph, from main module (not from named packages)
+		modload.LoadPackages(modload.LoaderState, ctx, loadOpts, "all") // rebuild graph, from main module (not from named packages)
 
 		sep := ""
 		for _, m := range matches {
diff --git a/src/cmd/go/internal/modfetch/zip_sum_test/zip_sum_test.go b/src/cmd/go/internal/modfetch/zip_sum_test/zip_sum_test.go
index 16cc1457058933..9d59d1a8ea8218 100644
--- a/src/cmd/go/internal/modfetch/zip_sum_test/zip_sum_test.go
+++ b/src/cmd/go/internal/modfetch/zip_sum_test/zip_sum_test.go
@@ -94,7 +94,7 @@ func TestZipSums(t *testing.T) {
 
 	cfg.GOPROXY = "direct"
 	cfg.GOSUMDB = "off"
-	modload.Init()
+	modload.Init(modload.LoaderState)
 
 	// Shard tests by downloading only every nth module when shard flags are set.
 	// This makes it easier to test small groups of modules quickly. We avoid
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index 5017f878ed3647..141e1708fa6ded 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -307,14 +307,14 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 
 	// Allow looking up modules for import paths when outside of a module.
 	// 'go get' is expected to do this, unlike other commands.
-	modload.AllowMissingModuleImports()
+	modload.AllowMissingModuleImports(modload.LoaderState)
 
 	// 'go get' no longer builds or installs packages, so there's nothing to do
 	// if there's no go.mod file.
 	// TODO(#40775): make modload.Init return ErrNoModRoot instead of exiting.
 	// We could handle that here by printing a different message.
-	modload.Init()
-	if !modload.HasModRoot() {
+	modload.Init(modload.LoaderState)
+	if !modload.HasModRoot(modload.LoaderState) {
 		base.Fatalf("go: go.mod file not found in current directory or any parent directory.\n" +
 			"\t'go get' is no longer supported outside a module.\n" +
 			"\tTo build and install a command, use 'go install' with a version,\n" +
@@ -424,9 +424,9 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	newReqs := reqsFromGoMod(modload.ModFile())
 	r.reportChanges(oldReqs, newReqs)
 
-	if gowork := modload.FindGoWork(base.Cwd()); gowork != "" {
+	if gowork := modload.FindGoWork(modload.LoaderState, base.Cwd()); gowork != "" {
 		wf, err := modload.ReadWorkFile(gowork)
-		if err == nil && modload.UpdateWorkGoVersion(wf, modload.LoaderState.MainModules.GoVersion()) {
+		if err == nil && modload.UpdateWorkGoVersion(wf, modload.LoaderState.MainModules.GoVersion(modload.LoaderState)) {
 			modload.WriteWorkFile(gowork, wf)
 		}
 	}
@@ -448,7 +448,7 @@ func updateTools(ctx context.Context, queries []*query, opts *modload.WriteOpts)
 		patterns = append(patterns, q.pattern)
 	}
 
-	matches, _ := modload.LoadPackages(ctx, pkgOpts, patterns...)
+	matches, _ := modload.LoadPackages(modload.LoaderState, ctx, pkgOpts, patterns...)
 	for i, m := range matches {
 		if queries[i].version == "none" {
 			opts.DropTools = append(opts.DropTools, m.Pkgs...)
@@ -574,7 +574,7 @@ func newResolver(ctx context.Context, queries []*query) *resolver {
 		buildListVersion: initialVersion,
 		initialVersion:   initialVersion,
 		nonesByPath:      map[string]*query{},
-		workspace:        loadWorkspace(modload.FindGoWork(base.Cwd())),
+		workspace:        loadWorkspace(modload.FindGoWork(modload.LoaderState, base.Cwd())),
 	}
 
 	for _, q := range queries {
@@ -645,7 +645,7 @@ func (r *resolver) noneForPath(mPath string) (nq *query, found bool) {
 // allowed versions.
 func (r *resolver) queryModule(ctx context.Context, mPath, query string, selected func(string) string) (module.Version, error) {
 	current := r.initialSelected(mPath)
-	rev, err := modload.Query(ctx, mPath, query, current, r.checkAllowedOr(query, selected))
+	rev, err := modload.Query(modload.LoaderState, ctx, mPath, query, current, r.checkAllowedOr(query, selected))
 	if err != nil {
 		return module.Version{}, err
 	}
@@ -655,7 +655,7 @@ func (r *resolver) queryModule(ctx context.Context, mPath, query string, selecte
 // queryPackages wraps modload.QueryPackage, substituting r.checkAllowedOr to
 // decide allowed versions.
 func (r *resolver) queryPackages(ctx context.Context, pattern, query string, selected func(string) string) (pkgMods []module.Version, err error) {
-	results, err := modload.QueryPackages(ctx, pattern, query, selected, r.checkAllowedOr(query, selected))
+	results, err := modload.QueryPackages(modload.LoaderState, ctx, pattern, query, selected, r.checkAllowedOr(query, selected))
 	if len(results) > 0 {
 		pkgMods = make([]module.Version, 0, len(results))
 		for _, qr := range results {
@@ -668,7 +668,7 @@ func (r *resolver) queryPackages(ctx context.Context, pattern, query string, sel
 // queryPattern wraps modload.QueryPattern, substituting r.checkAllowedOr to
 // decide allowed versions.
 func (r *resolver) queryPattern(ctx context.Context, pattern, query string, selected func(string) string) (pkgMods []module.Version, mod module.Version, err error) {
-	results, modOnly, err := modload.QueryPattern(ctx, pattern, query, selected, r.checkAllowedOr(query, selected))
+	results, modOnly, err := modload.QueryPattern(modload.LoaderState, ctx, pattern, query, selected, r.checkAllowedOr(query, selected))
 	if len(results) > 0 {
 		pkgMods = make([]module.Version, 0, len(results))
 		for _, qr := range results {
@@ -721,7 +721,7 @@ func (r *resolver) queryNone(ctx context.Context, q *query) {
 
 	if !q.isWildcard() {
 		q.pathOnce(q.pattern, func() pathSet {
-			hasModRoot := modload.HasModRoot()
+			hasModRoot := modload.HasModRoot(modload.LoaderState)
 			if hasModRoot && modload.LoaderState.MainModules.Contains(q.pattern) {
 				v := module.Version{Path: q.pattern}
 				// The user has explicitly requested to downgrade their own module to
@@ -746,7 +746,7 @@ func (r *resolver) queryNone(ctx context.Context, q *query) {
 			continue
 		}
 		q.pathOnce(curM.Path, func() pathSet {
-			if modload.HasModRoot() && curM.Version == "" && modload.LoaderState.MainModules.Contains(curM.Path) {
+			if modload.HasModRoot(modload.LoaderState) && curM.Version == "" && modload.LoaderState.MainModules.Contains(curM.Path) {
 				return errSet(&modload.QueryMatchesMainModulesError{MainModules: []module.Version{curM}, Pattern: q.pattern, Query: q.version})
 			}
 			return pathSet{mod: module.Version{Path: curM.Path, Version: "none"}}
@@ -766,7 +766,7 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 
 			// Absolute paths like C:\foo and relative paths like ../foo... are
 			// restricted to matching packages in the main module.
-			pkgPattern, mainModule := modload.LoaderState.MainModules.DirImportPath(ctx, q.pattern)
+			pkgPattern, mainModule := modload.LoaderState.MainModules.DirImportPath(modload.LoaderState, ctx, q.pattern)
 			if pkgPattern == "." {
 				modload.MustHaveModRoot()
 				versions := modload.LoaderState.MainModules.Versions()
@@ -1275,13 +1275,13 @@ func (r *resolver) loadPackages(ctx context.Context, patterns []string, findPack
 		return nil
 	}
 
-	_, pkgs := modload.LoadPackages(ctx, opts, patterns...)
+	_, pkgs := modload.LoadPackages(modload.LoaderState, ctx, opts, patterns...)
 	for _, pkgPath := range pkgs {
 		const (
 			parentPath  = ""
 			parentIsStd = false
 		)
-		_, _, err := modload.Lookup(parentPath, parentIsStd, pkgPath)
+		_, _, err := modload.Lookup(modload.LoaderState, parentPath, parentIsStd, pkgPath)
 		if err == nil {
 			continue
 		}
@@ -1651,7 +1651,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 			AllowErrors:              true,
 			SilenceNoGoErrors:        true,
 		}
-		matches, pkgs := modload.LoadPackages(ctx, pkgOpts, pkgPatterns...)
+		matches, pkgs := modload.LoadPackages(modload.LoaderState, ctx, pkgOpts, pkgPatterns...)
 		for _, m := range matches {
 			if len(m.Errs) > 0 {
 				base.SetExitStatus(1)
@@ -1659,7 +1659,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 			}
 		}
 		for _, pkg := range pkgs {
-			if dir, _, err := modload.Lookup("", false, pkg); err != nil {
+			if dir, _, err := modload.Lookup(modload.LoaderState, "", false, pkg); err != nil {
 				if dir != "" && errors.Is(err, imports.ErrNoGo) {
 					// Since dir is non-empty, we must have located source files
 					// associated with either the package or its test — ErrNoGo must
@@ -1690,7 +1690,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 		}
 	}
 
-	reqs := modload.LoadModFile(ctx)
+	reqs := modload.LoadModFile(modload.LoaderState, ctx)
 	for m := range relevantMods {
 		if reqs.IsDirect(m.Path) {
 			relevantMods[m] |= direct
@@ -1714,7 +1714,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 	for i := range retractions {
 		i := i
 		r.work.Add(func() {
-			err := modload.CheckRetractions(ctx, retractions[i].m)
+			err := modload.CheckRetractions(modload.LoaderState, ctx, retractions[i].m)
 			if _, ok := errors.AsType[*modload.ModuleRetractedError](err); ok {
 				retractions[i].message = err.Error()
 			}
@@ -1735,7 +1735,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 	for i := range deprecations {
 		i := i
 		r.work.Add(func() {
-			deprecation, err := modload.CheckDeprecation(ctx, deprecations[i].m)
+			deprecation, err := modload.CheckDeprecation(modload.LoaderState, ctx, deprecations[i].m)
 			if err != nil || deprecation == "" {
 				return
 			}
@@ -1765,7 +1765,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 		i := i
 		m := r.buildList[i]
 		mActual := m
-		if mRepl := modload.Replacement(m); mRepl.Path != "" {
+		if mRepl := modload.Replacement(modload.LoaderState, m); mRepl.Path != "" {
 			mActual = mRepl
 		}
 		old := module.Version{Path: m.Path, Version: r.initialVersion[m.Path]}
@@ -1773,7 +1773,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 			continue
 		}
 		oldActual := old
-		if oldRepl := modload.Replacement(old); oldRepl.Path != "" {
+		if oldRepl := modload.Replacement(modload.LoaderState, old); oldRepl.Path != "" {
 			oldActual = oldRepl
 		}
 		if mActual == oldActual || mActual.Version == "" || !modfetch.HaveSum(oldActual) {
@@ -1986,7 +1986,7 @@ func (r *resolver) updateBuildList(ctx context.Context, additions []module.Versi
 		}
 	}
 
-	changed, err := modload.EditBuildList(ctx, additions, resolved)
+	changed, err := modload.EditBuildList(modload.LoaderState, ctx, additions, resolved)
 	if err != nil {
 		if errors.Is(err, gover.ErrTooNew) {
 			toolchain.SwitchOrFatal(ctx, err)
diff --git a/src/cmd/go/internal/modget/query.go b/src/cmd/go/internal/modget/query.go
index 59f3023ffc4f41..7076bbadce898b 100644
--- a/src/cmd/go/internal/modget/query.go
+++ b/src/cmd/go/internal/modget/query.go
@@ -184,7 +184,7 @@ func (q *query) validate() error {
 
 	if q.pattern == "all" {
 		// If there is no main module, "all" is not meaningful.
-		if !modload.HasModRoot() {
+		if !modload.HasModRoot(modload.LoaderState) {
 			return fmt.Errorf(`cannot match "all": %v`, modload.ErrNoModRoot)
 		}
 		if !versionOkForMainModule(q.version) {
diff --git a/src/cmd/go/internal/modload/build.go b/src/cmd/go/internal/modload/build.go
index a8ab82d1ecb246..5b1b643d272dfd 100644
--- a/src/cmd/go/internal/modload/build.go
+++ b/src/cmd/go/internal/modload/build.go
@@ -51,8 +51,8 @@ func findStandardImportPath(path string) string {
 // a given package. If modules are not enabled or if the package is in the
 // standard library or if the package was not successfully loaded with
 // LoadPackages or ImportFromFiles, nil is returned.
-func PackageModuleInfo(ctx context.Context, pkgpath string) *modinfo.ModulePublic {
-	if isStandardImportPath(pkgpath) || !Enabled() {
+func PackageModuleInfo(loaderstate *State, ctx context.Context, pkgpath string) *modinfo.ModulePublic {
+	if isStandardImportPath(pkgpath) || !Enabled(loaderstate) {
 		return nil
 	}
 	m, ok := findModule(loaded, pkgpath)
@@ -60,23 +60,23 @@ func PackageModuleInfo(ctx context.Context, pkgpath string) *modinfo.ModulePubli
 		return nil
 	}
 
-	rs := LoadModFile(ctx)
-	return moduleInfo(ctx, rs, m, 0, nil)
+	rs := LoadModFile(loaderstate, ctx)
+	return moduleInfo(loaderstate, ctx, rs, m, 0, nil)
 }
 
 // PackageModRoot returns the module root directory for the module that provides
 // a given package. If modules are not enabled or if the package is in the
 // standard library or if the package was not successfully loaded with
 // LoadPackages or ImportFromFiles, the empty string is returned.
-func PackageModRoot(ctx context.Context, pkgpath string) string {
-	if isStandardImportPath(pkgpath) || !Enabled() || cfg.BuildMod == "vendor" {
+func PackageModRoot(loaderstate *State, ctx context.Context, pkgpath string) string {
+	if isStandardImportPath(pkgpath) || !Enabled(loaderstate) || cfg.BuildMod == "vendor" {
 		return ""
 	}
 	m, ok := findModule(loaded, pkgpath)
 	if !ok {
 		return ""
 	}
-	root, _, err := fetch(ctx, m)
+	root, _, err := fetch(loaderstate, ctx, m)
 	if err != nil {
 		return ""
 	}
@@ -84,26 +84,26 @@ func PackageModRoot(ctx context.Context, pkgpath string) string {
 }
 
 func ModuleInfo(ctx context.Context, path string) *modinfo.ModulePublic {
-	if !Enabled() {
+	if !Enabled(LoaderState) {
 		return nil
 	}
 
 	if path, vers, found := strings.Cut(path, "@"); found {
 		m := module.Version{Path: path, Version: vers}
-		return moduleInfo(ctx, nil, m, 0, nil)
+		return moduleInfo(LoaderState, ctx, nil, m, 0, nil)
 	}
 
-	rs := LoadModFile(ctx)
+	rs := LoadModFile(LoaderState, ctx)
 
 	var (
 		v  string
 		ok bool
 	)
 	if rs.pruning == pruned {
-		v, ok = rs.rootSelected(path)
+		v, ok = rs.rootSelected(LoaderState, path)
 	}
 	if !ok {
-		mg, err := rs.Graph(ctx)
+		mg, err := rs.Graph(LoaderState, ctx)
 		if err != nil {
 			base.Fatal(err)
 		}
@@ -119,7 +119,7 @@ func ModuleInfo(ctx context.Context, path string) *modinfo.ModulePublic {
 		}
 	}
 
-	return moduleInfo(ctx, rs, module.Version{Path: path, Version: v}, 0, nil)
+	return moduleInfo(LoaderState, ctx, rs, module.Version{Path: path, Version: v}, 0, nil)
 }
 
 // addUpdate fills in m.Update if an updated version is available.
@@ -128,7 +128,7 @@ func addUpdate(ctx context.Context, m *modinfo.ModulePublic) {
 		return
 	}
 
-	info, err := Query(ctx, m.Path, "upgrade", m.Version, CheckAllowed)
+	info, err := Query(LoaderState, ctx, m.Path, "upgrade", m.Version, CheckAllowed)
 	if _, ok := errors.AsType[*NoMatchingVersionError](err); ok ||
 		errors.Is(err, fs.ErrNotExist) ||
 		errors.Is(err, ErrDisallowed) {
@@ -221,7 +221,7 @@ func addVersions(ctx context.Context, m *modinfo.ModulePublic, listRetracted boo
 	if listRetracted {
 		allowed = CheckExclusions
 	}
-	v, origin, err := versions(ctx, m.Path, allowed)
+	v, origin, err := versions(LoaderState, ctx, m.Path, allowed)
 	if err != nil && m.Error == nil {
 		m.Error = &modinfo.ModuleError{Err: err.Error()}
 	}
@@ -231,12 +231,12 @@ func addVersions(ctx context.Context, m *modinfo.ModulePublic, listRetracted boo
 
 // addRetraction fills in m.Retracted if the module was retracted by its author.
 // m.Error is set if there's an error loading retraction information.
-func addRetraction(ctx context.Context, m *modinfo.ModulePublic) {
+func addRetraction(loaderstate *State, ctx context.Context, m *modinfo.ModulePublic) {
 	if m.Version == "" {
 		return
 	}
 
-	err := CheckRetractions(ctx, module.Version{Path: m.Path, Version: m.Version})
+	err := CheckRetractions(loaderstate, ctx, module.Version{Path: m.Path, Version: m.Version})
 	if err == nil {
 		return
 	} else if _, ok := errors.AsType[*NoMatchingVersionError](err); ok || errors.Is(err, fs.ErrNotExist) {
@@ -263,7 +263,7 @@ func addRetraction(ctx context.Context, m *modinfo.ModulePublic) {
 // addDeprecation fills in m.Deprecated if the module was deprecated by its
 // author. m.Error is set if there's an error loading deprecation information.
 func addDeprecation(ctx context.Context, m *modinfo.ModulePublic) {
-	deprecation, err := CheckDeprecation(ctx, module.Version{Path: m.Path, Version: m.Version})
+	deprecation, err := CheckDeprecation(LoaderState, ctx, module.Version{Path: m.Path, Version: m.Version})
 	if _, ok := errors.AsType[*NoMatchingVersionError](err); ok || errors.Is(err, fs.ErrNotExist) {
 		// Ignore "no matching version" and "not found" errors.
 		// This means the proxy has no matching version or no versions at all.
@@ -287,8 +287,8 @@ func addDeprecation(ctx context.Context, m *modinfo.ModulePublic) {
 // moduleInfo returns information about module m, loaded from the requirements
 // in rs (which may be nil to indicate that m was not loaded from a requirement
 // graph).
-func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode ListMode, reuse map[module.Version]*modinfo.ModulePublic) *modinfo.ModulePublic {
-	if m.Version == "" && LoaderState.MainModules.Contains(m.Path) {
+func moduleInfo(loaderstate *State, ctx context.Context, rs *Requirements, m module.Version, mode ListMode, reuse map[module.Version]*modinfo.ModulePublic) *modinfo.ModulePublic {
+	if m.Version == "" && loaderstate.MainModules.Contains(m.Path) {
 		info := &modinfo.ModulePublic{
 			Path:    m.Path,
 			Version: m.Version,
@@ -299,7 +299,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 		} else {
 			panic("internal error: GoVersion not set for main module")
 		}
-		if modRoot := LoaderState.MainModules.ModRoot(m); modRoot != "" {
+		if modRoot := loaderstate.MainModules.ModRoot(m); modRoot != "" {
 			info.Dir = modRoot
 			info.GoMod = modFilePath(modRoot)
 		}
@@ -322,7 +322,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 		}
 
 		checksumOk := func(suffix string) bool {
-			return rs == nil || m.Version == "" || !mustHaveSums() ||
+			return rs == nil || m.Version == "" || !mustHaveSums(loaderstate) ||
 				modfetch.HaveSum(module.Version{Path: m.Path, Version: m.Version + suffix})
 		}
 
@@ -330,7 +330,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 
 		if m.Version != "" {
 			if old := reuse[mod]; old != nil {
-				if err := checkReuse(ctx, mod, old.Origin); err == nil {
+				if err := checkReuse(loaderstate, ctx, mod, old.Origin); err == nil {
 					*m = *old
 					m.Query = ""
 					m.Dir = ""
@@ -338,7 +338,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 				}
 			}
 
-			if q, err := Query(ctx, m.Path, m.Version, "", nil); err != nil {
+			if q, err := Query(loaderstate, ctx, m.Path, m.Version, "", nil); err != nil {
 				m.Error = &modinfo.ModuleError{Err: err.Error()}
 			} else {
 				m.Version = q.Version
@@ -349,7 +349,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 		if m.GoVersion == "" && checksumOk("/go.mod") {
 			// Load the go.mod file to determine the Go version, since it hasn't
 			// already been populated from rawGoVersion.
-			if summary, err := rawGoModSummary(mod); err == nil && summary.goVersion != "" {
+			if summary, err := rawGoModSummary(loaderstate, mod); err == nil && summary.goVersion != "" {
 				m.GoVersion = summary.goVersion
 			}
 		}
@@ -377,7 +377,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 			}
 
 			if mode&ListRetracted != 0 {
-				addRetraction(ctx, m)
+				addRetraction(loaderstate, ctx, m)
 			}
 		}
 	}
@@ -389,7 +389,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 		return info
 	}
 
-	r := Replacement(m)
+	r := Replacement(loaderstate, m)
 	if r.Path == "" {
 		if cfg.BuildMod == "vendor" {
 			// It's tempting to fill in the "Dir" field to point within the vendor
@@ -418,7 +418,7 @@ func moduleInfo(ctx context.Context, rs *Requirements, m module.Version, mode Li
 		if filepath.IsAbs(r.Path) {
 			info.Replace.Dir = r.Path
 		} else {
-			info.Replace.Dir = filepath.Join(replaceRelativeTo(), r.Path)
+			info.Replace.Dir = filepath.Join(replaceRelativeTo(loaderstate), r.Path)
 		}
 		info.Replace.GoMod = filepath.Join(info.Replace.Dir, "go.mod")
 	}
diff --git a/src/cmd/go/internal/modload/buildlist.go b/src/cmd/go/internal/modload/buildlist.go
index cf64ee1dc210f9..54ec4d23ebe08e 100644
--- a/src/cmd/go/internal/modload/buildlist.go
+++ b/src/cmd/go/internal/modload/buildlist.go
@@ -104,21 +104,21 @@ func mustHaveGoRoot(roots []module.Version) {
 //
 // If vendoring is in effect, the caller must invoke initVendor on the returned
 // *Requirements before any other method.
-func newRequirements(pruning modPruning, rootModules []module.Version, direct map[string]bool) *Requirements {
+func newRequirements(loaderstate *State, pruning modPruning, rootModules []module.Version, direct map[string]bool) *Requirements {
 	mustHaveGoRoot(rootModules)
 
 	if pruning != workspace {
-		if LoaderState.workFilePath != "" {
+		if loaderstate.workFilePath != "" {
 			panic("in workspace mode, but pruning is not workspace in newRequirements")
 		}
 	}
 
 	if pruning != workspace {
-		if LoaderState.workFilePath != "" {
+		if loaderstate.workFilePath != "" {
 			panic("in workspace mode, but pruning is not workspace in newRequirements")
 		}
 		for i, m := range rootModules {
-			if m.Version == "" && LoaderState.MainModules.Contains(m.Path) {
+			if m.Version == "" && loaderstate.MainModules.Contains(m.Path) {
 				panic(fmt.Sprintf("newRequirements called with untrimmed build list: rootModules[%v] is a main module", i))
 			}
 			if m.Path == "" || m.Version == "" {
@@ -162,10 +162,10 @@ func (rs *Requirements) String() string {
 // initVendor initializes rs.graph from the given list of vendored module
 // dependencies, overriding the graph that would normally be loaded from module
 // requirements.
-func (rs *Requirements) initVendor(vendorList []module.Version) {
+func (rs *Requirements) initVendor(loaderstate *State, vendorList []module.Version) {
 	rs.graphOnce.Do(func() {
-		roots := LoaderState.MainModules.Versions()
-		if inWorkspaceMode() {
+		roots := loaderstate.MainModules.Versions()
+		if inWorkspaceMode(loaderstate) {
 			// Use rs.rootModules to pull in the go and toolchain roots
 			// from the go.work file and preserve the invariant that all
 			// of rs.rootModules are in mg.g.
@@ -176,7 +176,7 @@ func (rs *Requirements) initVendor(vendorList []module.Version) {
 		}
 
 		if rs.pruning == pruned {
-			mainModule := LoaderState.MainModules.mustGetSingleMainModule()
+			mainModule := loaderstate.MainModules.mustGetSingleMainModule(loaderstate)
 			// The roots of a single pruned module should already include every module in the
 			// vendor list, because the vendored modules are the same as those needed
 			// for graph pruning.
@@ -184,7 +184,7 @@ func (rs *Requirements) initVendor(vendorList []module.Version) {
 			// Just to be sure, we'll double-check that here.
 			inconsistent := false
 			for _, m := range vendorList {
-				if v, ok := rs.rootSelected(m.Path); !ok || v != m.Version {
+				if v, ok := rs.rootSelected(loaderstate, m.Path); !ok || v != m.Version {
 					base.Errorf("go: vendored module %v should be required explicitly in go.mod", m)
 					inconsistent = true
 				}
@@ -208,15 +208,15 @@ func (rs *Requirements) initVendor(vendorList []module.Version) {
 			// graph, but still distinguishes between direct and indirect
 			// dependencies.
 			vendorMod := module.Version{Path: "vendor/modules.txt", Version: ""}
-			if inWorkspaceMode() {
-				for _, m := range LoaderState.MainModules.Versions() {
-					reqs, _ := rootsFromModFile(m, LoaderState.MainModules.ModFile(m), omitToolchainRoot)
+			if inWorkspaceMode(loaderstate) {
+				for _, m := range loaderstate.MainModules.Versions() {
+					reqs, _ := rootsFromModFile(loaderstate, m, loaderstate.MainModules.ModFile(m), omitToolchainRoot)
 					mg.g.Require(m, append(reqs, vendorMod))
 				}
 				mg.g.Require(vendorMod, vendorList)
 
 			} else {
-				mainModule := LoaderState.MainModules.mustGetSingleMainModule()
+				mainModule := loaderstate.MainModules.mustGetSingleMainModule(loaderstate)
 				mg.g.Require(mainModule, append(rs.rootModules, vendorMod))
 				mg.g.Require(vendorMod, vendorList)
 			}
@@ -227,8 +227,8 @@ func (rs *Requirements) initVendor(vendorList []module.Version) {
 }
 
 // GoVersion returns the Go language version for the Requirements.
-func (rs *Requirements) GoVersion() string {
-	v, _ := rs.rootSelected("go")
+func (rs *Requirements) GoVersion(loaderstate *State) string {
+	v, _ := rs.rootSelected(loaderstate, "go")
 	if v == "" {
 		panic("internal error: missing go version in modload.Requirements")
 	}
@@ -238,8 +238,8 @@ func (rs *Requirements) GoVersion() string {
 // rootSelected returns the version of the root dependency with the given module
 // path, or the zero module.Version and ok=false if the module is not a root
 // dependency.
-func (rs *Requirements) rootSelected(path string) (version string, ok bool) {
-	if LoaderState.MainModules.Contains(path) {
+func (rs *Requirements) rootSelected(loaderstate *State, path string) (version string, ok bool) {
+	if loaderstate.MainModules.Contains(path) {
 		return "", true
 	}
 	if v, ok := rs.maxRootVersion[path]; ok {
@@ -252,9 +252,9 @@ func (rs *Requirements) rootSelected(path string) (version string, ok bool) {
 // of the same module or a requirement on any version of the main module.
 // Redundant requirements should be pruned, but they may influence version
 // selection.
-func (rs *Requirements) hasRedundantRoot() bool {
+func (rs *Requirements) hasRedundantRoot(loaderstate *State) bool {
 	for i, m := range rs.rootModules {
-		if LoaderState.MainModules.Contains(m.Path) || (i > 0 && m.Path == rs.rootModules[i-1].Path) {
+		if loaderstate.MainModules.Contains(m.Path) || (i > 0 && m.Path == rs.rootModules[i-1].Path) {
 			return true
 		}
 	}
@@ -269,9 +269,9 @@ func (rs *Requirements) hasRedundantRoot() bool {
 //
 // If the requirements of any relevant module fail to load, Graph also
 // returns a non-nil error of type *mvs.BuildListError.
-func (rs *Requirements) Graph(ctx context.Context) (*ModuleGraph, error) {
+func (rs *Requirements) Graph(loaderstate *State, ctx context.Context) (*ModuleGraph, error) {
 	rs.graphOnce.Do(func() {
-		mg, mgErr := readModGraph(ctx, rs.pruning, rs.rootModules, nil)
+		mg, mgErr := readModGraph(loaderstate, ctx, rs.pruning, rs.rootModules, nil)
 		rs.graph.Store(&cachedGraph{mg, mgErr})
 	})
 	cached := rs.graph.Load()
@@ -307,7 +307,7 @@ var readModGraphDebugOnce sync.Once
 //
 // Unlike LoadModGraph, readModGraph does not attempt to diagnose or update
 // inconsistent roots.
-func readModGraph(ctx context.Context, pruning modPruning, roots []module.Version, unprune map[module.Version]bool) (*ModuleGraph, error) {
+func readModGraph(loaderstate *State, ctx context.Context, pruning modPruning, roots []module.Version, unprune map[module.Version]bool) (*ModuleGraph, error) {
 	mustHaveGoRoot(roots)
 	if pruning == pruned {
 		// Enable diagnostics for lazy module loading
@@ -333,10 +333,10 @@ func readModGraph(ctx context.Context, pruning modPruning, roots []module.Versio
 	}
 
 	var graphRoots []module.Version
-	if inWorkspaceMode() {
+	if inWorkspaceMode(loaderstate) {
 		graphRoots = roots
 	} else {
-		graphRoots = LoaderState.MainModules.Versions()
+		graphRoots = loaderstate.MainModules.Versions()
 	}
 	var (
 		mu       sync.Mutex // guards mg.g and hasError during loading
@@ -347,10 +347,10 @@ func readModGraph(ctx context.Context, pruning modPruning, roots []module.Versio
 	)
 
 	if pruning != workspace {
-		if inWorkspaceMode() {
+		if inWorkspaceMode(loaderstate) {
 			panic("pruning is not workspace in workspace mode")
 		}
-		mg.g.Require(LoaderState.MainModules.mustGetSingleMainModule(), roots)
+		mg.g.Require(loaderstate.MainModules.mustGetSingleMainModule(loaderstate), roots)
 	}
 
 	type dedupKey struct {
@@ -367,7 +367,7 @@ func readModGraph(ctx context.Context, pruning modPruning, roots []module.Versio
 	// m's go.mod file indicates that it supports graph pruning.
 	loadOne := func(m module.Version) (*modFileSummary, error) {
 		return mg.loadCache.Do(m, func() (*modFileSummary, error) {
-			summary, err := goModSummary(m)
+			summary, err := goModSummary(loaderstate, m)
 
 			mu.Lock()
 			if err == nil {
@@ -527,12 +527,12 @@ func (mg *ModuleGraph) findError() error {
 	return nil
 }
 
-func (mg *ModuleGraph) allRootsSelected() bool {
+func (mg *ModuleGraph) allRootsSelected(loaderstate *State) bool {
 	var roots []module.Version
-	if inWorkspaceMode() {
-		roots = LoaderState.MainModules.Versions()
+	if inWorkspaceMode(loaderstate) {
+		roots = loaderstate.MainModules.Versions()
 	} else {
-		roots, _ = mg.g.RequiredBy(LoaderState.MainModules.mustGetSingleMainModule())
+		roots, _ = mg.g.RequiredBy(loaderstate.MainModules.mustGetSingleMainModule(loaderstate))
 	}
 	for _, m := range roots {
 		if mg.Selected(m.Path) != m.Version {
@@ -553,13 +553,13 @@ func (mg *ModuleGraph) allRootsSelected() bool {
 // LoadModGraph need only be called if LoadPackages is not,
 // typically in commands that care about modules but no particular package.
 func LoadModGraph(ctx context.Context, goVersion string) (*ModuleGraph, error) {
-	rs, err := loadModFile(ctx, nil)
+	rs, err := loadModFile(LoaderState, ctx, nil)
 	if err != nil {
 		return nil, err
 	}
 
 	if goVersion != "" {
-		v, _ := rs.rootSelected("go")
+		v, _ := rs.rootSelected(LoaderState, "go")
 		if gover.Compare(v, gover.GoStrictVersion) >= 0 && gover.Compare(goVersion, v) < 0 {
 			return nil, fmt.Errorf("requested Go version %s cannot load module graph (requires Go >= %s)", goVersion, v)
 		}
@@ -569,13 +569,13 @@ func LoadModGraph(ctx context.Context, goVersion string) (*ModuleGraph, error) {
 			// Use newRequirements instead of convertDepth because convertDepth
 			// also updates roots; here, we want to report the unmodified roots
 			// even though they may seem inconsistent.
-			rs = newRequirements(unpruned, rs.rootModules, rs.direct)
+			rs = newRequirements(LoaderState, unpruned, rs.rootModules, rs.direct)
 		}
 
-		return rs.Graph(ctx)
+		return rs.Graph(LoaderState, ctx)
 	}
 
-	rs, mg, err := expandGraph(ctx, rs)
+	rs, mg, err := expandGraph(LoaderState, ctx, rs)
 	if err != nil {
 		return nil, err
 	}
@@ -594,22 +594,22 @@ func LoadModGraph(ctx context.Context, goVersion string) (*ModuleGraph, error) {
 // from those roots and any error encountered while loading that graph.
 // expandGraph returns non-nil requirements and a non-nil graph regardless of
 // errors. On error, the roots might not be updated to be consistent.
-func expandGraph(ctx context.Context, rs *Requirements) (*Requirements, *ModuleGraph, error) {
-	mg, mgErr := rs.Graph(ctx)
+func expandGraph(loaderstate *State, ctx context.Context, rs *Requirements) (*Requirements, *ModuleGraph, error) {
+	mg, mgErr := rs.Graph(loaderstate, ctx)
 	if mgErr != nil {
 		// Without the graph, we can't update the roots: we don't know which
 		// versions of transitive dependencies would be selected.
 		return rs, mg, mgErr
 	}
 
-	if !mg.allRootsSelected() {
+	if !mg.allRootsSelected(loaderstate) {
 		// The roots of rs are not consistent with the rest of the graph. Update
 		// them. In an unpruned module this is a no-op for the build list as a whole —
 		// it just promotes what were previously transitive requirements to be
 		// roots — but in a pruned module it may pull in previously-irrelevant
 		// transitive dependencies.
 
-		newRS, rsErr := updateRoots(ctx, rs.direct, rs, nil, nil, false)
+		newRS, rsErr := updateRoots(loaderstate, ctx, rs.direct, rs, nil, nil, false)
 		if rsErr != nil {
 			// Failed to update roots, perhaps because of an error in a transitive
 			// dependency needed for the update. Return the original Requirements
@@ -617,7 +617,7 @@ func expandGraph(ctx context.Context, rs *Requirements) (*Requirements, *ModuleG
 			return rs, mg, rsErr
 		}
 		rs = newRS
-		mg, mgErr = rs.Graph(ctx)
+		mg, mgErr = rs.Graph(loaderstate, ctx)
 	}
 
 	return rs, mg, mgErr
@@ -639,16 +639,16 @@ func expandGraph(ctx context.Context, rs *Requirements) (*Requirements, *ModuleG
 // On success, EditBuildList reports whether the selected version of any module
 // in the build list may have been changed (possibly to or from "none") as a
 // result.
-func EditBuildList(ctx context.Context, add, mustSelect []module.Version) (changed bool, err error) {
-	rs, changed, err := editRequirements(ctx, LoadModFile(ctx), add, mustSelect)
+func EditBuildList(loaderstate *State, ctx context.Context, add, mustSelect []module.Version) (changed bool, err error) {
+	rs, changed, err := editRequirements(loaderstate, ctx, LoadModFile(loaderstate, ctx), add, mustSelect)
 	if err != nil {
 		return false, err
 	}
-	LoaderState.requirements = rs
+	loaderstate.requirements = rs
 	return changed, nil
 }
 
-func overrideRoots(ctx context.Context, rs *Requirements, replace []module.Version) *Requirements {
+func overrideRoots(loaderstate *State, ctx context.Context, rs *Requirements, replace []module.Version) *Requirements {
 	drop := make(map[string]bool)
 	for _, m := range replace {
 		drop[m.Path] = true
@@ -661,7 +661,7 @@ func overrideRoots(ctx context.Context, rs *Requirements, replace []module.Versi
 	}
 	roots = append(roots, replace...)
 	gover.ModSort(roots)
-	return newRequirements(rs.pruning, roots, rs.direct)
+	return newRequirements(loaderstate, rs.pruning, roots, rs.direct)
 }
 
 // A ConstraintError describes inconsistent constraints in EditBuildList
@@ -765,28 +765,28 @@ func (c Conflict) String() string {
 // tidyRoots trims the root dependencies to the minimal requirements needed to
 // both retain the same versions of all packages in pkgs and satisfy the
 // graph-pruning invariants (if applicable).
-func tidyRoots(ctx context.Context, rs *Requirements, pkgs []*loadPkg) (*Requirements, error) {
-	mainModule := LoaderState.MainModules.mustGetSingleMainModule()
+func tidyRoots(loaderstate *State, ctx context.Context, rs *Requirements, pkgs []*loadPkg) (*Requirements, error) {
+	mainModule := loaderstate.MainModules.mustGetSingleMainModule(loaderstate)
 	if rs.pruning == unpruned {
-		return tidyUnprunedRoots(ctx, mainModule, rs, pkgs)
+		return tidyUnprunedRoots(loaderstate, ctx, mainModule, rs, pkgs)
 	}
-	return tidyPrunedRoots(ctx, mainModule, rs, pkgs)
+	return tidyPrunedRoots(loaderstate, ctx, mainModule, rs, pkgs)
 }
 
-func updateRoots(ctx context.Context, direct map[string]bool, rs *Requirements, pkgs []*loadPkg, add []module.Version, rootsImported bool) (*Requirements, error) {
+func updateRoots(loaderstate *State, ctx context.Context, direct map[string]bool, rs *Requirements, pkgs []*loadPkg, add []module.Version, rootsImported bool) (*Requirements, error) {
 	switch rs.pruning {
 	case unpruned:
-		return updateUnprunedRoots(ctx, direct, rs, add)
+		return updateUnprunedRoots(loaderstate, ctx, direct, rs, add)
 	case pruned:
-		return updatePrunedRoots(ctx, direct, rs, pkgs, add, rootsImported)
+		return updatePrunedRoots(loaderstate, ctx, direct, rs, pkgs, add, rootsImported)
 	case workspace:
-		return updateWorkspaceRoots(ctx, direct, rs, add)
+		return updateWorkspaceRoots(loaderstate, ctx, direct, rs, add)
 	default:
 		panic(fmt.Sprintf("unsupported pruning mode: %v", rs.pruning))
 	}
 }
 
-func updateWorkspaceRoots(ctx context.Context, direct map[string]bool, rs *Requirements, add []module.Version) (*Requirements, error) {
+func updateWorkspaceRoots(loaderstate *State, ctx context.Context, direct map[string]bool, rs *Requirements, add []module.Version) (*Requirements, error) {
 	if len(add) != 0 {
 		// add should be empty in workspace mode because workspace mode implies
 		// -mod=readonly, which in turn implies no new requirements. The code path
@@ -797,7 +797,7 @@ func updateWorkspaceRoots(ctx context.Context, direct map[string]bool, rs *Requi
 		// return an error.
 		panic("add is not empty")
 	}
-	return newRequirements(workspace, rs.rootModules, direct), nil
+	return newRequirements(loaderstate, workspace, rs.rootModules, direct), nil
 }
 
 // tidyPrunedRoots returns a minimal set of root requirements that maintains the
@@ -816,16 +816,16 @@ func updateWorkspaceRoots(ctx context.Context, direct map[string]bool, rs *Requi
 // To ensure that the loading process eventually converges, the caller should
 // add any needed roots from the tidy root set (without removing existing untidy
 // roots) until the set of roots has converged.
-func tidyPrunedRoots(ctx context.Context, mainModule module.Version, old *Requirements, pkgs []*loadPkg) (*Requirements, error) {
+func tidyPrunedRoots(loaderstate *State, ctx context.Context, mainModule module.Version, old *Requirements, pkgs []*loadPkg) (*Requirements, error) {
 	var (
 		roots      []module.Version
 		pathIsRoot = map[string]bool{mainModule.Path: true}
 	)
-	if v, ok := old.rootSelected("go"); ok {
+	if v, ok := old.rootSelected(loaderstate, "go"); ok {
 		roots = append(roots, module.Version{Path: "go", Version: v})
 		pathIsRoot["go"] = true
 	}
-	if v, ok := old.rootSelected("toolchain"); ok {
+	if v, ok := old.rootSelected(loaderstate, "toolchain"); ok {
 		roots = append(roots, module.Version{Path: "toolchain", Version: v})
 		pathIsRoot["toolchain"] = true
 	}
@@ -847,7 +847,7 @@ func tidyPrunedRoots(ctx context.Context, mainModule module.Version, old *Requir
 		if !pkg.flags.has(pkgInAll) {
 			continue
 		}
-		if pkg.fromExternalModule() && !pathIsRoot[pkg.mod.Path] {
+		if pkg.fromExternalModule(loaderstate) && !pathIsRoot[pkg.mod.Path] {
 			roots = append(roots, pkg.mod)
 			pathIsRoot[pkg.mod.Path] = true
 		}
@@ -855,11 +855,11 @@ func tidyPrunedRoots(ctx context.Context, mainModule module.Version, old *Requir
 		queued[pkg] = true
 	}
 	gover.ModSort(roots)
-	tidy := newRequirements(pruned, roots, old.direct)
+	tidy := newRequirements(loaderstate, pruned, roots, old.direct)
 
 	for len(queue) > 0 {
 		roots = tidy.rootModules
-		mg, err := tidy.Graph(ctx)
+		mg, err := tidy.Graph(loaderstate, ctx)
 		if err != nil {
 			return nil, err
 		}
@@ -892,12 +892,12 @@ func tidyPrunedRoots(ctx context.Context, mainModule module.Version, old *Requir
 
 		if len(roots) > len(tidy.rootModules) {
 			gover.ModSort(roots)
-			tidy = newRequirements(pruned, roots, tidy.direct)
+			tidy = newRequirements(loaderstate, pruned, roots, tidy.direct)
 		}
 	}
 
 	roots = tidy.rootModules
-	_, err := tidy.Graph(ctx)
+	_, err := tidy.Graph(loaderstate, ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -921,7 +921,7 @@ func tidyPrunedRoots(ctx context.Context, mainModule module.Version, old *Requir
 			pkg := pkg
 			q.Add(func() {
 				skipModFile := true
-				_, _, _, _, err := importFromModules(ctx, pkg.path, tidy, nil, skipModFile)
+				_, _, _, _, err := importFromModules(loaderstate, ctx, pkg.path, tidy, nil, skipModFile)
 				if _, ok := errors.AsType[*AmbiguousImportError](err); ok {
 					disambiguateRoot.Store(pkg.mod, true)
 				}
@@ -938,8 +938,8 @@ func tidyPrunedRoots(ctx context.Context, mainModule module.Version, old *Requir
 
 		if len(roots) > len(tidy.rootModules) {
 			module.Sort(roots)
-			tidy = newRequirements(pruned, roots, tidy.direct)
-			_, err = tidy.Graph(ctx)
+			tidy = newRequirements(loaderstate, pruned, roots, tidy.direct)
+			_, err = tidy.Graph(loaderstate, ctx)
 			if err != nil {
 				return nil, err
 			}
@@ -999,7 +999,7 @@ func tidyPrunedRoots(ctx context.Context, mainModule module.Version, old *Requir
 //
 // (See https://golang.org/design/36460-lazy-module-loading#invariants for more
 // detail.)
-func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirements, pkgs []*loadPkg, add []module.Version, rootsImported bool) (*Requirements, error) {
+func updatePrunedRoots(loaderstate *State, ctx context.Context, direct map[string]bool, rs *Requirements, pkgs []*loadPkg, add []module.Version, rootsImported bool) (*Requirements, error) {
 	roots := rs.rootModules
 	rootsUpgraded := false
 
@@ -1009,7 +1009,7 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 	// either pkgInAll or pkgIsRoot is included as a root.”
 	needSort := false
 	for _, pkg := range pkgs {
-		if !pkg.fromExternalModule() {
+		if !pkg.fromExternalModule(loaderstate) {
 			// pkg was not loaded from a module dependency, so we don't need
 			// to do anything special to maintain that dependency.
 			continue
@@ -1058,7 +1058,7 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 			continue
 		}
 
-		if _, ok := rs.rootSelected(pkg.mod.Path); ok {
+		if _, ok := rs.rootSelected(loaderstate, pkg.mod.Path); ok {
 			// It is possible that the main module's go.mod file is incomplete or
 			// otherwise erroneous — for example, perhaps the author forgot to 'git
 			// add' their updated go.mod file after adding a new package import, or
@@ -1094,7 +1094,7 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 	}
 
 	for _, m := range add {
-		if v, ok := rs.rootSelected(m.Path); !ok || gover.ModCompare(m.Path, v, m.Version) < 0 {
+		if v, ok := rs.rootSelected(loaderstate, m.Path); !ok || gover.ModCompare(m.Path, v, m.Version) < 0 {
 			roots = append(roots, m)
 			rootsUpgraded = true
 			needSort = true
@@ -1111,7 +1111,7 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 			// We've added or upgraded one or more roots, so load the full module
 			// graph so that we can update those roots to be consistent with other
 			// requirements.
-			if mustHaveCompleteRequirements() {
+			if mustHaveCompleteRequirements(loaderstate) {
 				// Our changes to the roots may have moved dependencies into or out of
 				// the graph-pruning horizon, which could in turn change the selected
 				// versions of other modules. (For pruned modules adding or removing an
@@ -1119,9 +1119,9 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 				return rs, errGoModDirty
 			}
 
-			rs = newRequirements(pruned, roots, direct)
+			rs = newRequirements(loaderstate, pruned, roots, direct)
 			var err error
-			mg, err = rs.Graph(ctx)
+			mg, err = rs.Graph(loaderstate, ctx)
 			if err != nil {
 				return rs, err
 			}
@@ -1135,20 +1135,20 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 				// We've already loaded the full module graph, which includes the
 				// requirements of all of the root modules — even the transitive
 				// requirements, if they are unpruned!
-				mg, _ = rs.Graph(ctx)
+				mg, _ = rs.Graph(loaderstate, ctx)
 			} else if cfg.BuildMod == "vendor" {
 				// We can't spot-check the requirements of other modules because we
 				// don't in general have their go.mod files available in the vendor
 				// directory. (Fortunately this case is impossible, because mg.graph is
 				// always non-nil in vendor mode!)
 				panic("internal error: rs.graph is unexpectedly nil with -mod=vendor")
-			} else if !spotCheckRoots(ctx, rs, spotCheckRoot) {
+			} else if !spotCheckRoots(loaderstate, ctx, rs, spotCheckRoot) {
 				// We spot-checked the explicit requirements of the roots that are
 				// relevant to the packages we've loaded. Unfortunately, they're
 				// inconsistent in some way; we need to load the full module graph
 				// so that we can fix the roots properly.
 				var err error
-				mg, err = rs.Graph(ctx)
+				mg, err = rs.Graph(loaderstate, ctx)
 				if err != nil {
 					return rs, err
 				}
@@ -1158,7 +1158,7 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 		roots = make([]module.Version, 0, len(rs.rootModules))
 		rootsUpgraded = false
 		inRootPaths := make(map[string]bool, len(rs.rootModules)+1)
-		for _, mm := range LoaderState.MainModules.Versions() {
+		for _, mm := range loaderstate.MainModules.Versions() {
 			inRootPaths[mm.Path] = true
 		}
 		for _, m := range rs.rootModules {
@@ -1184,7 +1184,7 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 
 			var v string
 			if mg == nil {
-				v, _ = rs.rootSelected(m.Path)
+				v, _ = rs.rootSelected(loaderstate, m.Path)
 			} else {
 				v = mg.Selected(m.Path)
 			}
@@ -1218,12 +1218,12 @@ func updatePrunedRoots(ctx context.Context, direct map[string]bool, rs *Requirem
 		// preserve its cached ModuleGraph (if any).
 		return rs, nil
 	}
-	return newRequirements(pruned, roots, direct), nil
+	return newRequirements(loaderstate, pruned, roots, direct), nil
 }
 
 // spotCheckRoots reports whether the versions of the roots in rs satisfy the
 // explicit requirements of the modules in mods.
-func spotCheckRoots(ctx context.Context, rs *Requirements, mods map[module.Version]bool) bool {
+func spotCheckRoots(loaderstate *State, ctx context.Context, rs *Requirements, mods map[module.Version]bool) bool {
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
@@ -1235,14 +1235,14 @@ func spotCheckRoots(ctx context.Context, rs *Requirements, mods map[module.Versi
 				return
 			}
 
-			summary, err := goModSummary(m)
+			summary, err := goModSummary(loaderstate, m)
 			if err != nil {
 				cancel()
 				return
 			}
 
 			for _, r := range summary.require {
-				if v, ok := rs.rootSelected(r.Path); ok && gover.ModCompare(r.Path, v, r.Version) < 0 {
+				if v, ok := rs.rootSelected(loaderstate, r.Path); ok && gover.ModCompare(r.Path, v, r.Version) < 0 {
 					cancel()
 					return
 				}
@@ -1264,7 +1264,7 @@ func spotCheckRoots(ctx context.Context, rs *Requirements, mods map[module.Versi
 // the selected version of every module that provided or lexically could have
 // provided a package in pkgs, and includes the selected version of every such
 // module in direct as a root.
-func tidyUnprunedRoots(ctx context.Context, mainModule module.Version, old *Requirements, pkgs []*loadPkg) (*Requirements, error) {
+func tidyUnprunedRoots(loaderstate *State, ctx context.Context, mainModule module.Version, old *Requirements, pkgs []*loadPkg) (*Requirements, error) {
 	var (
 		// keep is a set of modules that provide packages or are needed to
 		// disambiguate imports.
@@ -1292,16 +1292,16 @@ func tidyUnprunedRoots(ctx context.Context, mainModule module.Version, old *Requ
 		// without its sum. See #47738.
 		altMods = map[string]string{}
 	)
-	if v, ok := old.rootSelected("go"); ok {
+	if v, ok := old.rootSelected(loaderstate, "go"); ok {
 		keep = append(keep, module.Version{Path: "go", Version: v})
 		keptPath["go"] = true
 	}
-	if v, ok := old.rootSelected("toolchain"); ok {
+	if v, ok := old.rootSelected(loaderstate, "toolchain"); ok {
 		keep = append(keep, module.Version{Path: "toolchain", Version: v})
 		keptPath["toolchain"] = true
 	}
 	for _, pkg := range pkgs {
-		if !pkg.fromExternalModule() {
+		if !pkg.fromExternalModule(loaderstate) {
 			continue
 		}
 		if m := pkg.mod; !keptPath[m.Path] {
@@ -1350,7 +1350,7 @@ func tidyUnprunedRoots(ctx context.Context, mainModule module.Version, old *Requ
 		}
 	}
 
-	return newRequirements(unpruned, min, old.direct), nil
+	return newRequirements(loaderstate, unpruned, min, old.direct), nil
 }
 
 // updateUnprunedRoots returns a set of root requirements that includes the selected
@@ -1367,8 +1367,8 @@ func tidyUnprunedRoots(ctx context.Context, mainModule module.Version, old *Requ
 //     by a dependency in add.
 //  4. Every version in add is selected at its given version unless upgraded by
 //     (the dependencies of) an existing root or another module in add.
-func updateUnprunedRoots(ctx context.Context, direct map[string]bool, rs *Requirements, add []module.Version) (*Requirements, error) {
-	mg, err := rs.Graph(ctx)
+func updateUnprunedRoots(loaderstate *State, ctx context.Context, direct map[string]bool, rs *Requirements, add []module.Version) (*Requirements, error) {
+	mg, err := rs.Graph(loaderstate, ctx)
 	if err != nil {
 		// We can't ignore errors in the module graph even if the user passed the -e
 		// flag to try to push past them. If we can't load the complete module
@@ -1376,7 +1376,7 @@ func updateUnprunedRoots(ctx context.Context, direct map[string]bool, rs *Requir
 		return rs, err
 	}
 
-	if mustHaveCompleteRequirements() {
+	if mustHaveCompleteRequirements(loaderstate) {
 		// Instead of actually updating the requirements, just check that no updates
 		// are needed.
 		if rs == nil {
@@ -1396,7 +1396,7 @@ func updateUnprunedRoots(ctx context.Context, direct map[string]bool, rs *Requir
 			}
 		}
 		for mPath := range direct {
-			if _, ok := rs.rootSelected(mPath); !ok {
+			if _, ok := rs.rootSelected(loaderstate, mPath); !ok {
 				// Module m is supposed to be listed explicitly, but isn't.
 				//
 				// Note that this condition is also detected (and logged with more
@@ -1435,7 +1435,7 @@ func updateUnprunedRoots(ctx context.Context, direct map[string]bool, rs *Requir
 	// This is only for convenience and clarity for end users: in an unpruned module,
 	// the choice of explicit vs. implicit dependency has no impact on MVS
 	// selection (for itself or any other module).
-	keep := append(mg.BuildList()[LoaderState.MainModules.Len():], add...)
+	keep := append(mg.BuildList()[loaderstate.MainModules.Len():], add...)
 	for _, m := range keep {
 		if direct[m.Path] && !inRootPaths[m.Path] {
 			rootPaths = append(rootPaths, m.Path)
@@ -1444,14 +1444,14 @@ func updateUnprunedRoots(ctx context.Context, direct map[string]bool, rs *Requir
 	}
 
 	var roots []module.Version
-	for _, mainModule := range LoaderState.MainModules.Versions() {
+	for _, mainModule := range loaderstate.MainModules.Versions() {
 		min, err := mvs.Req(mainModule, rootPaths, &mvsReqs{roots: keep})
 		if err != nil {
 			return rs, err
 		}
 		roots = append(roots, min...)
 	}
-	if LoaderState.MainModules.Len() > 1 {
+	if loaderstate.MainModules.Len() > 1 {
 		gover.ModSort(roots)
 	}
 	if rs.pruning == unpruned && slices.Equal(roots, rs.rootModules) && maps.Equal(direct, rs.direct) {
@@ -1460,12 +1460,12 @@ func updateUnprunedRoots(ctx context.Context, direct map[string]bool, rs *Requir
 		return rs, nil
 	}
 
-	return newRequirements(unpruned, roots, direct), nil
+	return newRequirements(loaderstate, unpruned, roots, direct), nil
 }
 
 // convertPruning returns a version of rs with the given pruning behavior.
 // If rs already has the given pruning, convertPruning returns rs unmodified.
-func convertPruning(ctx context.Context, rs *Requirements, pruning modPruning) (*Requirements, error) {
+func convertPruning(loaderstate *State, ctx context.Context, rs *Requirements, pruning modPruning) (*Requirements, error) {
 	if rs.pruning == pruning {
 		return rs, nil
 	} else if rs.pruning == workspace || pruning == workspace {
@@ -1477,7 +1477,7 @@ func convertPruning(ctx context.Context, rs *Requirements, pruning modPruning) (
 		// pruned module graph are a superset of the roots of an unpruned one, so
 		// we don't need to add any new roots — we just need to drop the ones that
 		// are redundant, which is exactly what updateUnprunedRoots does.
-		return updateUnprunedRoots(ctx, rs.direct, rs, nil)
+		return updateUnprunedRoots(loaderstate, ctx, rs.direct, rs, nil)
 	}
 
 	// We are converting an unpruned module to a pruned one.
@@ -1487,9 +1487,9 @@ func convertPruning(ctx context.Context, rs *Requirements, pruning modPruning) (
 	// root set! “Include the transitive dependencies of every module in the build
 	// list” is exactly what happens in a pruned module if we promote every module
 	// in the build list to a root.
-	mg, err := rs.Graph(ctx)
+	mg, err := rs.Graph(loaderstate, ctx)
 	if err != nil {
 		return rs, err
 	}
-	return newRequirements(pruned, mg.BuildList()[LoaderState.MainModules.Len():], rs.direct), nil
+	return newRequirements(loaderstate, pruned, mg.BuildList()[loaderstate.MainModules.Len():], rs.direct), nil
 }
diff --git a/src/cmd/go/internal/modload/edit.go b/src/cmd/go/internal/modload/edit.go
index 96d864545d042a..72d0f754224456 100644
--- a/src/cmd/go/internal/modload/edit.go
+++ b/src/cmd/go/internal/modload/edit.go
@@ -42,7 +42,7 @@ import (
 // If pruning is enabled, the roots of the edited requirements include an
 // explicit entry for each module path in tryUpgrade, mustSelect, and the roots
 // of rs, unless the selected version for the module path is "none".
-func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSelect []module.Version) (edited *Requirements, changed bool, err error) {
+func editRequirements(loaderstate *State, ctx context.Context, rs *Requirements, tryUpgrade, mustSelect []module.Version) (edited *Requirements, changed bool, err error) {
 	if rs.pruning == workspace {
 		panic("editRequirements cannot edit workspace requirements")
 	}
@@ -82,7 +82,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 	}
 
 	if rootPruning != rs.pruning {
-		rs, err = convertPruning(ctx, rs, rootPruning)
+		rs, err = convertPruning(loaderstate, ctx, rs, rootPruning)
 		if err != nil {
 			return orig, false, err
 		}
@@ -100,13 +100,13 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 		// dependencies, so we need to treat everything in the build list as
 		// potentially relevant — that is, as what would be a “root” in a module
 		// with graph pruning enabled.
-		mg, err := rs.Graph(ctx)
+		mg, err := rs.Graph(loaderstate, ctx)
 		if err != nil {
 			// If we couldn't load the graph, we don't know what its requirements were
 			// to begin with, so we can't edit those requirements in a coherent way.
 			return orig, false, err
 		}
-		bl := mg.BuildList()[LoaderState.MainModules.Len():]
+		bl := mg.BuildList()[loaderstate.MainModules.Len():]
 		selectedRoot = make(map[string]string, len(bl))
 		for _, m := range bl {
 			selectedRoot[m.Path] = m.Version
@@ -224,7 +224,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 		// of every root. The upgraded roots are in addition to the original
 		// roots, so we will have enough information to trace a path to each
 		// conflict we discover from one or more of the original roots.
-		mg, upgradedRoots, err := extendGraph(ctx, rootPruning, roots, selectedRoot)
+		mg, upgradedRoots, err := extendGraph(loaderstate, ctx, rootPruning, roots, selectedRoot)
 		if err != nil {
 			if mg == nil {
 				return orig, false, err
@@ -391,7 +391,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 			// the edit. We want to make sure we consider keeping it as-is,
 			// even if it wouldn't normally be included. (For example, it might
 			// be a pseudo-version or pre-release.)
-			origMG, _ := orig.Graph(ctx)
+			origMG, _ := orig.Graph(loaderstate, ctx)
 			origV := origMG.Selected(m.Path)
 
 			if conflict.Err != nil && origV == m.Version {
@@ -415,7 +415,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 			rejectedRoot[m] = true
 			prev := m
 			for {
-				prev, err = previousVersion(ctx, prev)
+				prev, err = previousVersion(loaderstate, ctx, prev)
 				if gover.ModCompare(m.Path, m.Version, origV) > 0 && (gover.ModCompare(m.Path, prev.Version, origV) < 0 || err != nil) {
 					// previousVersion skipped over origV. Insert it into the order.
 					prev.Version = origV
@@ -515,13 +515,13 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 
 		// The modules in mustSelect are always promoted to be explicit.
 		for _, m := range mustSelect {
-			if m.Version != "none" && !LoaderState.MainModules.Contains(m.Path) {
+			if m.Version != "none" && !loaderstate.MainModules.Contains(m.Path) {
 				rootPaths = append(rootPaths, m.Path)
 			}
 		}
 
 		for _, m := range roots {
-			if v, ok := rs.rootSelected(m.Path); ok && (v == m.Version || rs.direct[m.Path]) {
+			if v, ok := rs.rootSelected(loaderstate, m.Path); ok && (v == m.Version || rs.direct[m.Path]) {
 				// m.Path was formerly a root, and either its version hasn't changed or
 				// we believe that it provides a package directly imported by a package
 				// or test in the main module. For now we'll assume that it is still
@@ -532,7 +532,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 			}
 		}
 
-		roots, err = mvs.Req(LoaderState.MainModules.mustGetSingleMainModule(), rootPaths, &mvsReqs{roots: roots})
+		roots, err = mvs.Req(loaderstate.MainModules.mustGetSingleMainModule(loaderstate), rootPaths, &mvsReqs{roots: roots})
 		if err != nil {
 			return nil, false, err
 		}
@@ -563,7 +563,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 			direct[m.Path] = true
 		}
 	}
-	edited = newRequirements(rootPruning, roots, direct)
+	edited = newRequirements(loaderstate, rootPruning, roots, direct)
 
 	// If we ended up adding a dependency that upgrades our go version far enough
 	// to activate pruning, we must convert the edited Requirements in order to
@@ -578,7 +578,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 	// those two modules will never be downgraded due to a conflict with any other
 	// constraint.
 	if rootPruning == unpruned {
-		if v, ok := edited.rootSelected("go"); ok && pruningForGoVersion(v) == pruned {
+		if v, ok := edited.rootSelected(loaderstate, "go"); ok && pruningForGoVersion(v) == pruned {
 			// Since we computed the edit with the unpruned graph, and the pruned
 			// graph is a strict subset of the unpruned graph, this conversion
 			// preserves the exact (edited) build list that we already computed.
@@ -587,7 +587,7 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 			// the graph. 'go get' will check for that sort of transition and log a
 			// message reminding the user how to clean up this mess we're about to
 			// make. 😅
-			edited, err = convertPruning(ctx, edited, pruned)
+			edited, err = convertPruning(loaderstate, ctx, edited, pruned)
 			if err != nil {
 				return orig, false, err
 			}
@@ -607,9 +607,9 @@ func editRequirements(ctx context.Context, rs *Requirements, tryUpgrade, mustSel
 // The extended graph is useful for diagnosing version conflicts: for each
 // selected module version, it can provide a complete path of requirements from
 // some root to that version.
-func extendGraph(ctx context.Context, rootPruning modPruning, roots []module.Version, selectedRoot map[string]string) (mg *ModuleGraph, upgradedRoot map[module.Version]bool, err error) {
+func extendGraph(loaderstate *State, ctx context.Context, rootPruning modPruning, roots []module.Version, selectedRoot map[string]string) (mg *ModuleGraph, upgradedRoot map[module.Version]bool, err error) {
 	for {
-		mg, err = readModGraph(ctx, rootPruning, roots, upgradedRoot)
+		mg, err = readModGraph(loaderstate, ctx, rootPruning, roots, upgradedRoot)
 		// We keep on going even if err is non-nil until we reach a steady state.
 		// (Note that readModGraph returns a non-nil *ModuleGraph even in case of
 		// errors.) The caller may be able to fix the errors by adjusting versions,
diff --git a/src/cmd/go/internal/modload/import.go b/src/cmd/go/internal/modload/import.go
index 392fe3edd77b52..a2a98289b0ed77 100644
--- a/src/cmd/go/internal/modload/import.go
+++ b/src/cmd/go/internal/modload/import.go
@@ -262,7 +262,7 @@ func (e *invalidImportError) Unwrap() error {
 // (https://go.dev/issue/56222) for modules with 'go' versions between 1.17 and
 // 1.20, preventing unnecessary go.sum churn and network access in those
 // modules.
-func importFromModules(ctx context.Context, path string, rs *Requirements, mg *ModuleGraph, skipModFile bool) (m module.Version, modroot, dir string, altMods []module.Version, err error) {
+func importFromModules(loaderstate *State, ctx context.Context, path string, rs *Requirements, mg *ModuleGraph, skipModFile bool) (m module.Version, modroot, dir string, altMods []module.Version, err error) {
 	invalidf := func(format string, args ...interface{}) (module.Version, string, string, []module.Version, error) {
 		return module.Version{}, "", "", nil, &invalidImportError{
 			importPath: path,
@@ -299,12 +299,12 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 	// Is the package in the standard library?
 	pathIsStd := search.IsStandardImportPath(path)
 	if pathIsStd && modindex.IsStandardPackage(cfg.GOROOT, cfg.BuildContext.Compiler, path) {
-		for _, mainModule := range LoaderState.MainModules.Versions() {
-			if LoaderState.MainModules.InGorootSrc(mainModule) {
-				if dir, ok, err := dirInModule(path, LoaderState.MainModules.PathPrefix(mainModule), LoaderState.MainModules.ModRoot(mainModule), true); err != nil {
-					return module.Version{}, LoaderState.MainModules.ModRoot(mainModule), dir, nil, err
+		for _, mainModule := range loaderstate.MainModules.Versions() {
+			if loaderstate.MainModules.InGorootSrc(mainModule) {
+				if dir, ok, err := dirInModule(path, loaderstate.MainModules.PathPrefix(mainModule), loaderstate.MainModules.ModRoot(mainModule), true); err != nil {
+					return module.Version{}, loaderstate.MainModules.ModRoot(mainModule), dir, nil, err
 				} else if ok {
-					return mainModule, LoaderState.MainModules.ModRoot(mainModule), dir, nil, nil
+					return mainModule, loaderstate.MainModules.ModRoot(mainModule), dir, nil, nil
 				}
 			}
 		}
@@ -321,10 +321,10 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 	// Everything must be in the main modules or the main module's or workspace's vendor directory.
 	if cfg.BuildMod == "vendor" {
 		var mainErr error
-		for _, mainModule := range LoaderState.MainModules.Versions() {
-			modRoot := LoaderState.MainModules.ModRoot(mainModule)
+		for _, mainModule := range loaderstate.MainModules.Versions() {
+			modRoot := loaderstate.MainModules.ModRoot(mainModule)
 			if modRoot != "" {
-				dir, mainOK, err := dirInModule(path, LoaderState.MainModules.PathPrefix(mainModule), modRoot, true)
+				dir, mainOK, err := dirInModule(path, loaderstate.MainModules.PathPrefix(mainModule), modRoot, true)
 				if mainErr == nil {
 					mainErr = err
 				}
@@ -336,8 +336,8 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 			}
 		}
 
-		if HasModRoot() {
-			vendorDir := VendorDir()
+		if HasModRoot(loaderstate) {
+			vendorDir := VendorDir(loaderstate)
 			dir, inVendorDir, _ := dirInModule(path, "", vendorDir, false)
 			if inVendorDir {
 				readVendorList(vendorDir)
@@ -345,13 +345,13 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 				// vendor/modules.txt does not exist or the user manually added directories to the vendor directory.
 				// Go 1.23 and later require vendored packages to be present in modules.txt to be imported.
 				_, ok := vendorPkgModule[path]
-				if ok || (gover.Compare(LoaderState.MainModules.GoVersion(), gover.ExplicitModulesTxtImportVersion) < 0) {
+				if ok || (gover.Compare(loaderstate.MainModules.GoVersion(loaderstate), gover.ExplicitModulesTxtImportVersion) < 0) {
 					mods = append(mods, vendorPkgModule[path])
 					dirs = append(dirs, dir)
 					roots = append(roots, vendorDir)
 				} else {
 					subCommand := "mod"
-					if inWorkspaceMode() {
+					if inWorkspaceMode(loaderstate) {
 						subCommand = "work"
 					}
 					fmt.Fprintf(os.Stderr, "go: ignoring package %s which exists in the vendor directory but is missing from vendor/modules.txt. To sync the vendor directory run go %s vendor.\n", path, subCommand)
@@ -399,7 +399,7 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 				ok bool
 			)
 			if mg == nil {
-				v, ok = rs.rootSelected(prefix)
+				v, ok = rs.rootSelected(loaderstate, prefix)
 			} else {
 				v, ok = mg.Selected(prefix), true
 			}
@@ -408,7 +408,7 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 			}
 			m := module.Version{Path: prefix, Version: v}
 
-			root, isLocal, err := fetch(ctx, m)
+			root, isLocal, err := fetch(loaderstate, ctx, m)
 			if err != nil {
 				if _, ok := errors.AsType[*sumMissingError](err); ok {
 					// We are missing a sum needed to fetch a module in the build list.
@@ -471,8 +471,8 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 			// If the module graph is pruned and this is a test-only dependency
 			// of a package in "all", we didn't necessarily load that file
 			// when we read the module graph, so do it now to be sure.
-			if !skipModFile && cfg.BuildMod != "vendor" && mods[0].Path != "" && !LoaderState.MainModules.Contains(mods[0].Path) {
-				if _, err := goModSummary(mods[0]); err != nil {
+			if !skipModFile && cfg.BuildMod != "vendor" && mods[0].Path != "" && !loaderstate.MainModules.Contains(mods[0].Path) {
+				if _, err := goModSummary(loaderstate, mods[0]); err != nil {
 					return module.Version{}, "", "", nil, err
 				}
 			}
@@ -483,7 +483,7 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 			// We checked the full module graph and still didn't find the
 			// requested package.
 			var queryErr error
-			if !HasModRoot() {
+			if !HasModRoot(loaderstate) {
 				queryErr = ErrNoModRoot
 			}
 			return module.Version{}, "", "", nil, &ImportMissingError{Path: path, QueryErr: queryErr, isStd: pathIsStd}
@@ -491,7 +491,7 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 
 		// So far we've checked the root dependencies.
 		// Load the full module graph and try again.
-		mg, err = rs.Graph(ctx)
+		mg, err = rs.Graph(loaderstate, ctx)
 		if err != nil {
 			// We might be missing one or more transitive (implicit) dependencies from
 			// the module graph, so we can't return an ImportMissingError here — one
@@ -507,12 +507,12 @@ func importFromModules(ctx context.Context, path string, rs *Requirements, mg *M
 //
 // Unlike QueryPattern, queryImport prefers to add a replaced version of a
 // module *before* checking the proxies for a version to add.
-func queryImport(ctx context.Context, path string, rs *Requirements) (module.Version, error) {
+func queryImport(loaderstate *State, ctx context.Context, path string, rs *Requirements) (module.Version, error) {
 	// To avoid spurious remote fetches, try the latest replacement for each
 	// module (golang.org/issue/26241).
 	var mods []module.Version
-	if LoaderState.MainModules != nil { // TODO(#48912): Ensure MainModules exists at this point, and remove the check.
-		for mp, mv := range LoaderState.MainModules.HighestReplaced() {
+	if loaderstate.MainModules != nil { // TODO(#48912): Ensure MainModules exists at this point, and remove the check.
+		for mp, mv := range loaderstate.MainModules.HighestReplaced() {
 			if !maybeInModule(path, mp) {
 				continue
 			}
@@ -528,7 +528,7 @@ func queryImport(ctx context.Context, path string, rs *Requirements) (module.Ver
 					mv = module.ZeroPseudoVersion("v0")
 				}
 			}
-			mg, err := rs.Graph(ctx)
+			mg, err := rs.Graph(loaderstate, ctx)
 			if err != nil {
 				return module.Version{}, err
 			}
@@ -547,7 +547,7 @@ func queryImport(ctx context.Context, path string, rs *Requirements) (module.Ver
 		return len(mods[i].Path) > len(mods[j].Path)
 	})
 	for _, m := range mods {
-		root, isLocal, err := fetch(ctx, m)
+		root, isLocal, err := fetch(loaderstate, ctx, m)
 		if err != nil {
 			if _, ok := errors.AsType[*sumMissingError](err); ok {
 				return module.Version{}, &ImportMissingSumError{importPath: path}
@@ -567,7 +567,7 @@ func queryImport(ctx context.Context, path string, rs *Requirements) (module.Ver
 		// The package path is not valid to fetch remotely,
 		// so it can only exist in a replaced module,
 		// and we know from the above loop that it is not.
-		replacement := Replacement(mods[0])
+		replacement := Replacement(loaderstate, mods[0])
 		return module.Version{}, &PackageNotInModuleError{
 			Mod:         mods[0],
 			Query:       "latest",
@@ -607,12 +607,12 @@ func queryImport(ctx context.Context, path string, rs *Requirements) (module.Ver
 	// and return m, dir, ImportMissingError.
 	fmt.Fprintf(os.Stderr, "go: finding module for package %s\n", path)
 
-	mg, err := rs.Graph(ctx)
+	mg, err := rs.Graph(loaderstate, ctx)
 	if err != nil {
 		return module.Version{}, err
 	}
 
-	candidates, err := QueryPackages(ctx, path, "latest", mg.Selected, CheckAllowed)
+	candidates, err := QueryPackages(loaderstate, ctx, path, "latest", mg.Selected, CheckAllowed)
 	if err != nil {
 		if errors.Is(err, fs.ErrNotExist) {
 			// Return "cannot find module providing package […]" instead of whatever
@@ -747,15 +747,15 @@ func dirInModule(path, mpath, mdir string, isLocal bool) (dir string, haveGoFile
 //
 // The isLocal return value reports whether the replacement,
 // if any, is local to the filesystem.
-func fetch(ctx context.Context, mod module.Version) (dir string, isLocal bool, err error) {
-	if modRoot := LoaderState.MainModules.ModRoot(mod); modRoot != "" {
+func fetch(loaderstate *State, ctx context.Context, mod module.Version) (dir string, isLocal bool, err error) {
+	if modRoot := loaderstate.MainModules.ModRoot(mod); modRoot != "" {
 		return modRoot, true, nil
 	}
-	if r := Replacement(mod); r.Path != "" {
+	if r := Replacement(loaderstate, mod); r.Path != "" {
 		if r.Version == "" {
 			dir = r.Path
 			if !filepath.IsAbs(dir) {
-				dir = filepath.Join(replaceRelativeTo(), dir)
+				dir = filepath.Join(replaceRelativeTo(loaderstate), dir)
 			}
 			// Ensure that the replacement directory actually exists:
 			// dirInModule does not report errors for missing modules,
@@ -780,7 +780,7 @@ func fetch(ctx context.Context, mod module.Version) (dir string, isLocal bool, e
 		mod = r
 	}
 
-	if mustHaveSums() && !modfetch.HaveSum(mod) {
+	if mustHaveSums(loaderstate) && !modfetch.HaveSum(mod) {
 		return "", false, module.VersionError(mod, &sumMissingError{})
 	}
 
@@ -790,8 +790,8 @@ func fetch(ctx context.Context, mod module.Version) (dir string, isLocal bool, e
 
 // mustHaveSums reports whether we require that all checksums
 // needed to load or build packages are already present in the go.sum file.
-func mustHaveSums() bool {
-	return HasModRoot() && cfg.BuildMod == "readonly" && !inWorkspaceMode()
+func mustHaveSums(loaderstate *State) bool {
+	return HasModRoot(loaderstate) && cfg.BuildMod == "readonly" && !inWorkspaceMode(loaderstate)
 }
 
 type sumMissingError struct {
diff --git a/src/cmd/go/internal/modload/import_test.go b/src/cmd/go/internal/modload/import_test.go
index f6b8bb90992735..a5c4b837a0be12 100644
--- a/src/cmd/go/internal/modload/import_test.go
+++ b/src/cmd/go/internal/modload/import_test.go
@@ -69,12 +69,12 @@ func TestQueryImport(t *testing.T) {
 	LoaderState.RootMode = NoRoot
 
 	ctx := context.Background()
-	rs := LoadModFile(ctx)
+	rs := LoadModFile(LoaderState, ctx)
 
 	for _, tt := range importTests {
 		t.Run(strings.ReplaceAll(tt.path, "/", "_"), func(t *testing.T) {
 			// Note that there is no build list, so Import should always fail.
-			m, err := queryImport(ctx, tt.path, rs)
+			m, err := queryImport(LoaderState, ctx, tt.path, rs)
 
 			if tt.err == "" {
 				if err != nil {
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 31fe6327735736..20751528862ce2 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -64,7 +64,7 @@ func EnterModule(ctx context.Context, enterModroot string) {
 	modfetch.Reset()
 
 	LoaderState.modRoots = []string{enterModroot}
-	LoadModFile(ctx)
+	LoadModFile(LoaderState, ctx)
 }
 
 // EnterWorkspace enters workspace mode from module mode, applying the updated requirements to the main
@@ -73,9 +73,9 @@ func EnterModule(ctx context.Context, enterModroot string) {
 // EnterWorkspace will modify the global state they depend on in a non-thread-safe way.
 func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	// Find the identity of the main module that will be updated before we reset modload state.
-	mm := LoaderState.MainModules.mustGetSingleMainModule()
+	mm := LoaderState.MainModules.mustGetSingleMainModule(LoaderState)
 	// Get the updated modfile we will use for that module.
-	_, _, updatedmodfile, err := UpdateGoModFromReqs(ctx, WriteOpts{})
+	_, _, updatedmodfile, err := UpdateGoModFromReqs(LoaderState, ctx, WriteOpts{})
 	if err != nil {
 		return nil, err
 	}
@@ -85,12 +85,12 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	LoaderState.ForceUseModules = true
 
 	// Load in workspace mode.
-	InitWorkfile()
-	LoadModFile(ctx)
+	InitWorkfile(LoaderState)
+	LoadModFile(LoaderState, ctx)
 
 	// Update the content of the previous main module, and recompute the requirements.
 	*LoaderState.MainModules.ModFile(mm) = *updatedmodfile
-	LoaderState.requirements = requirementsFromModFiles(ctx, LoaderState.MainModules.workFile, slices.Collect(maps.Values(LoaderState.MainModules.modFiles)), nil)
+	LoaderState.requirements = requirementsFromModFiles(LoaderState, ctx, LoaderState.MainModules.workFile, slices.Collect(maps.Values(LoaderState.MainModules.modFiles)), nil)
 
 	return func() {
 		setState(oldstate)
@@ -182,12 +182,12 @@ func (mms *MainModuleSet) InGorootSrc(m module.Version) bool {
 	return mms.inGorootSrc[m]
 }
 
-func (mms *MainModuleSet) mustGetSingleMainModule() module.Version {
+func (mms *MainModuleSet) mustGetSingleMainModule(loaderstate *State) module.Version {
 	if mms == nil || len(mms.versions) == 0 {
 		panic("internal error: mustGetSingleMainModule called in context with no main modules")
 	}
 	if len(mms.versions) != 1 {
-		if inWorkspaceMode() {
+		if inWorkspaceMode(loaderstate) {
 			panic("internal error: mustGetSingleMainModule called in workspace mode")
 		} else {
 			panic("internal error: multiple main modules present outside of workspace mode")
@@ -196,14 +196,14 @@ func (mms *MainModuleSet) mustGetSingleMainModule() module.Version {
 	return mms.versions[0]
 }
 
-func (mms *MainModuleSet) GetSingleIndexOrNil() *modFileIndex {
+func (mms *MainModuleSet) GetSingleIndexOrNil(loaderstate *State) *modFileIndex {
 	if mms == nil {
 		return nil
 	}
 	if len(mms.versions) == 0 {
 		return nil
 	}
-	return mms.indices[mms.mustGetSingleMainModule()]
+	return mms.indices[mms.mustGetSingleMainModule(loaderstate)]
 }
 
 func (mms *MainModuleSet) Index(m module.Version) *modFileIndex {
@@ -246,12 +246,12 @@ func (mms *MainModuleSet) HighestReplaced() map[string]string {
 
 // GoVersion returns the go version set on the single module, in module mode,
 // or the go.work file in workspace mode.
-func (mms *MainModuleSet) GoVersion() string {
-	if inWorkspaceMode() {
+func (mms *MainModuleSet) GoVersion(loaderstate *State) string {
+	if inWorkspaceMode(loaderstate) {
 		return gover.FromGoWork(mms.workFile)
 	}
 	if mms != nil && len(mms.versions) == 1 {
-		f := mms.ModFile(mms.mustGetSingleMainModule())
+		f := mms.ModFile(mms.mustGetSingleMainModule(loaderstate))
 		if f == nil {
 			// Special case: we are outside a module, like 'go run x.go'.
 			// Assume the local Go version.
@@ -266,15 +266,15 @@ func (mms *MainModuleSet) GoVersion() string {
 // Godebugs returns the godebug lines set on the single module, in module mode,
 // or on the go.work file in workspace mode.
 // The caller must not modify the result.
-func (mms *MainModuleSet) Godebugs() []*modfile.Godebug {
-	if inWorkspaceMode() {
+func (mms *MainModuleSet) Godebugs(loaderstate *State) []*modfile.Godebug {
+	if inWorkspaceMode(loaderstate) {
 		if mms.workFile != nil {
 			return mms.workFile.Godebug
 		}
 		return nil
 	}
 	if mms != nil && len(mms.versions) == 1 {
-		f := mms.ModFile(mms.mustGetSingleMainModule())
+		f := mms.ModFile(mms.mustGetSingleMainModule(loaderstate))
 		if f == nil {
 			// Special case: we are outside a module, like 'go run x.go'.
 			return nil
@@ -315,16 +315,16 @@ const (
 // To make permanent changes to the require statements
 // in go.mod, edit it before loading.
 func ModFile() *modfile.File {
-	Init()
-	modFile := LoaderState.MainModules.ModFile(LoaderState.MainModules.mustGetSingleMainModule())
+	Init(LoaderState)
+	modFile := LoaderState.MainModules.ModFile(LoaderState.MainModules.mustGetSingleMainModule(LoaderState))
 	if modFile == nil {
-		die()
+		die(LoaderState)
 	}
 	return modFile
 }
 
-func BinDir() string {
-	Init()
+func BinDir(loaderstate *State) string {
+	Init(loaderstate)
 	if cfg.GOBIN != "" {
 		return cfg.GOBIN
 	}
@@ -337,13 +337,13 @@ func BinDir() string {
 // InitWorkfile initializes the workFilePath variable for commands that
 // operate in workspace mode. It should not be called by other commands,
 // for example 'go mod tidy', that don't operate in workspace mode.
-func InitWorkfile() {
+func InitWorkfile(loaderstate *State) {
 	// Initialize fsys early because we need overlay to read go.work file.
 	fips140.Init()
 	if err := fsys.Init(); err != nil {
 		base.Fatal(err)
 	}
-	LoaderState.workFilePath = FindGoWork(base.Cwd())
+	loaderstate.workFilePath = FindGoWork(loaderstate, base.Cwd())
 }
 
 // FindGoWork returns the name of the go.work file for this command,
@@ -351,8 +351,8 @@ func InitWorkfile() {
 // Most code should use Init and Enabled rather than use this directly.
 // It is exported mainly for Go toolchain switching, which must process
 // the go.work very early at startup.
-func FindGoWork(wd string) string {
-	if LoaderState.RootMode == NoRoot {
+func FindGoWork(loaderstate *State, wd string) string {
+	if loaderstate.RootMode == NoRoot {
 		return ""
 	}
 
@@ -371,8 +371,8 @@ func FindGoWork(wd string) string {
 
 // WorkFilePath returns the absolute path of the go.work file, or "" if not in
 // workspace mode. WorkFilePath must be called after InitWorkfile.
-func WorkFilePath() string {
-	return LoaderState.workFilePath
+func WorkFilePath(loaderstate *State) string {
+	return loaderstate.workFilePath
 }
 
 // Reset clears all the initialized, cached state about the use of modules,
@@ -451,11 +451,11 @@ var LoaderState = NewState()
 // current module (if any), sets environment variables for Git subprocesses, and
 // configures the cfg, codehost, load, modfetch, and search packages for use
 // with modules.
-func Init() {
-	if LoaderState.initialized {
+func Init(loaderstate *State) {
+	if loaderstate.initialized {
 		return
 	}
-	LoaderState.initialized = true
+	loaderstate.initialized = true
 
 	fips140.Init()
 
@@ -468,11 +468,11 @@ func Init() {
 	default:
 		base.Fatalf("go: unknown environment setting GO111MODULE=%s", env)
 	case "auto":
-		mustUseModules = LoaderState.ForceUseModules
+		mustUseModules = loaderstate.ForceUseModules
 	case "on", "":
 		mustUseModules = true
 	case "off":
-		if LoaderState.ForceUseModules {
+		if loaderstate.ForceUseModules {
 			base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
 		}
 		mustUseModules = false
@@ -496,15 +496,15 @@ func Init() {
 	if os.Getenv("GCM_INTERACTIVE") == "" {
 		os.Setenv("GCM_INTERACTIVE", "never")
 	}
-	if LoaderState.modRoots != nil {
+	if loaderstate.modRoots != nil {
 		// modRoot set before Init was called ("go mod init" does this).
 		// No need to search for go.mod.
-	} else if LoaderState.RootMode == NoRoot {
+	} else if loaderstate.RootMode == NoRoot {
 		if cfg.ModFile != "" && !base.InGOFLAGS("-modfile") {
 			base.Fatalf("go: -modfile cannot be used with commands that ignore the current module")
 		}
-		LoaderState.modRoots = nil
-	} else if LoaderState.workFilePath != "" {
+		loaderstate.modRoots = nil
+	} else if loaderstate.workFilePath != "" {
 		// We're in workspace mode, which implies module mode.
 		if cfg.ModFile != "" {
 			base.Fatalf("go: -modfile cannot be used in workspace mode")
@@ -514,7 +514,7 @@ func Init() {
 			if cfg.ModFile != "" {
 				base.Fatalf("go: cannot find main module, but -modfile was set.\n\t-modfile cannot be used to set the module root directory.")
 			}
-			if LoaderState.RootMode == NeedRoot {
+			if loaderstate.RootMode == NeedRoot {
 				base.Fatal(ErrNoModRoot)
 			}
 			if !mustUseModules {
@@ -529,14 +529,14 @@ func Init() {
 			// It's a bit of a peculiar thing to disallow but quite mysterious
 			// when it happens. See golang.org/issue/26708.
 			fmt.Fprintf(os.Stderr, "go: warning: ignoring go.mod in system temp root %v\n", os.TempDir())
-			if LoaderState.RootMode == NeedRoot {
+			if loaderstate.RootMode == NeedRoot {
 				base.Fatal(ErrNoModRoot)
 			}
 			if !mustUseModules {
 				return
 			}
 		} else {
-			LoaderState.modRoots = []string{modRoot}
+			loaderstate.modRoots = []string{modRoot}
 		}
 	}
 	if cfg.ModFile != "" && !strings.HasSuffix(cfg.ModFile, ".mod") {
@@ -545,13 +545,13 @@ func Init() {
 
 	// We're in module mode. Set any global variables that need to be set.
 	cfg.ModulesEnabled = true
-	setDefaultBuildMod()
+	setDefaultBuildMod(loaderstate)
 	list := filepath.SplitList(cfg.BuildContext.GOPATH)
 	if len(list) > 0 && list[0] != "" {
 		gopath = list[0]
 		if _, err := fsys.Stat(filepath.Join(gopath, "go.mod")); err == nil {
 			fmt.Fprintf(os.Stderr, "go: warning: ignoring go.mod in $GOPATH %v\n", gopath)
-			if LoaderState.RootMode == NeedRoot {
+			if loaderstate.RootMode == NeedRoot {
 				base.Fatal(ErrNoModRoot)
 			}
 			if !mustUseModules {
@@ -622,49 +622,49 @@ func FindGoMod(wd string) string {
 // If modules are enabled but there is no main module, Enabled returns true
 // and then the first use of module information will call die
 // (usually through MustModRoot).
-func Enabled() bool {
-	Init()
-	return LoaderState.modRoots != nil || cfg.ModulesEnabled
+func Enabled(loaderstate *State) bool {
+	Init(loaderstate)
+	return loaderstate.modRoots != nil || cfg.ModulesEnabled
 }
 
-func VendorDir() string {
-	if inWorkspaceMode() {
-		return filepath.Join(filepath.Dir(WorkFilePath()), "vendor")
+func VendorDir(loaderstate *State) string {
+	if inWorkspaceMode(loaderstate) {
+		return filepath.Join(filepath.Dir(WorkFilePath(loaderstate)), "vendor")
 	}
 	// Even if -mod=vendor, we could be operating with no mod root (and thus no
 	// vendor directory). As long as there are no dependencies that is expected
 	// to work. See script/vendor_outside_module.txt.
-	modRoot := LoaderState.MainModules.ModRoot(LoaderState.MainModules.mustGetSingleMainModule())
+	modRoot := loaderstate.MainModules.ModRoot(loaderstate.MainModules.mustGetSingleMainModule(loaderstate))
 	if modRoot == "" {
 		panic("vendor directory does not exist when in single module mode outside of a module")
 	}
 	return filepath.Join(modRoot, "vendor")
 }
 
-func inWorkspaceMode() bool {
-	if !LoaderState.initialized {
+func inWorkspaceMode(loaderstate *State) bool {
+	if !loaderstate.initialized {
 		panic("inWorkspaceMode called before modload.Init called")
 	}
-	if !Enabled() {
+	if !Enabled(loaderstate) {
 		return false
 	}
-	return LoaderState.workFilePath != ""
+	return loaderstate.workFilePath != ""
 }
 
 // HasModRoot reports whether a main module or main modules are present.
 // HasModRoot may return false even if Enabled returns true: for example, 'get'
 // does not require a main module.
-func HasModRoot() bool {
-	Init()
-	return LoaderState.modRoots != nil
+func HasModRoot(loaderstate *State) bool {
+	Init(loaderstate)
+	return loaderstate.modRoots != nil
 }
 
 // MustHaveModRoot checks that a main module or main modules are present,
 // and calls base.Fatalf if there are no main modules.
 func MustHaveModRoot() {
-	Init()
-	if !HasModRoot() {
-		die()
+	Init(LoaderState)
+	if !HasModRoot(LoaderState) {
+		die(LoaderState)
 	}
 }
 
@@ -686,11 +686,11 @@ func modFilePath(modRoot string) string {
 	return filepath.Join(modRoot, "go.mod")
 }
 
-func die() {
+func die(loaderstate *State) {
 	if cfg.Getenv("GO111MODULE") == "off" {
 		base.Fatalf("go: modules disabled by GO111MODULE=off; see 'go help modules'")
 	}
-	if !inWorkspaceMode() {
+	if !inWorkspaceMode(loaderstate) {
 		if dir, name := findAltConfig(base.Cwd()); dir != "" {
 			rel, err := filepath.Rel(base.Cwd(), dir)
 			if err != nil {
@@ -711,7 +711,7 @@ func die() {
 type noMainModulesError struct{}
 
 func (e noMainModulesError) Error() string {
-	if inWorkspaceMode() {
+	if inWorkspaceMode(LoaderState) {
 		return "no modules were found in the current workspace; see 'go help work'"
 	}
 	return "go.mod file not found in current directory or any parent directory; see 'go help modules'"
@@ -868,33 +868,33 @@ func UpdateWorkFile(wf *modfile.WorkFile) {
 // other, but unlike LoadModGraph does not load the full module graph or check
 // it for global consistency. Most callers outside of the modload package should
 // use LoadModGraph instead.
-func LoadModFile(ctx context.Context) *Requirements {
-	rs, err := loadModFile(ctx, nil)
+func LoadModFile(loaderstate *State, ctx context.Context) *Requirements {
+	rs, err := loadModFile(loaderstate, ctx, nil)
 	if err != nil {
 		base.Fatal(err)
 	}
 	return rs
 }
 
-func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error) {
-	if LoaderState.requirements != nil {
-		return LoaderState.requirements, nil
+func loadModFile(loaderstate *State, ctx context.Context, opts *PackageOpts) (*Requirements, error) {
+	if loaderstate.requirements != nil {
+		return loaderstate.requirements, nil
 	}
 
-	Init()
+	Init(loaderstate)
 	var workFile *modfile.WorkFile
-	if inWorkspaceMode() {
+	if inWorkspaceMode(loaderstate) {
 		var err error
-		workFile, LoaderState.modRoots, err = LoadWorkFile(LoaderState.workFilePath)
+		workFile, loaderstate.modRoots, err = LoadWorkFile(loaderstate.workFilePath)
 		if err != nil {
 			return nil, err
 		}
-		for _, modRoot := range LoaderState.modRoots {
+		for _, modRoot := range loaderstate.modRoots {
 			sumFile := strings.TrimSuffix(modFilePath(modRoot), ".mod") + ".sum"
 			modfetch.WorkspaceGoSumFiles = append(modfetch.WorkspaceGoSumFiles, sumFile)
 		}
-		modfetch.GoSumFile = LoaderState.workFilePath + ".sum"
-	} else if len(LoaderState.modRoots) == 0 {
+		modfetch.GoSumFile = loaderstate.workFilePath + ".sum"
+	} else if len(loaderstate.modRoots) == 0 {
 		// We're in module mode, but not inside a module.
 		//
 		// Commands like 'go build', 'go run', 'go list' have no go.mod file to
@@ -913,25 +913,25 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		//
 		// See golang.org/issue/32027.
 	} else {
-		modfetch.GoSumFile = strings.TrimSuffix(modFilePath(LoaderState.modRoots[0]), ".mod") + ".sum"
+		modfetch.GoSumFile = strings.TrimSuffix(modFilePath(loaderstate.modRoots[0]), ".mod") + ".sum"
 	}
-	if len(LoaderState.modRoots) == 0 {
+	if len(loaderstate.modRoots) == 0 {
 		// TODO(#49228): Instead of creating a fake module with an empty modroot,
 		// make MainModules.Len() == 0 mean that we're in module mode but not inside
 		// any module.
 		mainModule := module.Version{Path: "command-line-arguments"}
-		LoaderState.MainModules = makeMainModules([]module.Version{mainModule}, []string{""}, []*modfile.File{nil}, []*modFileIndex{nil}, nil)
+		loaderstate.MainModules = makeMainModules(loaderstate, []module.Version{mainModule}, []string{""}, []*modfile.File{nil}, []*modFileIndex{nil}, nil)
 		var (
 			goVersion string
 			pruning   modPruning
 			roots     []module.Version
 			direct    = map[string]bool{"go": true}
 		)
-		if inWorkspaceMode() {
+		if inWorkspaceMode(loaderstate) {
 			// Since we are in a workspace, the Go version for the synthetic
 			// "command-line-arguments" module must not exceed the Go version
 			// for the workspace.
-			goVersion = LoaderState.MainModules.GoVersion()
+			goVersion = loaderstate.MainModules.GoVersion(loaderstate)
 			pruning = workspace
 			roots = []module.Version{
 				mainModule,
@@ -947,26 +947,26 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			}
 		}
 		rawGoVersion.Store(mainModule, goVersion)
-		LoaderState.requirements = newRequirements(pruning, roots, direct)
+		loaderstate.requirements = newRequirements(loaderstate, pruning, roots, direct)
 		if cfg.BuildMod == "vendor" {
 			// For issue 56536: Some users may have GOFLAGS=-mod=vendor set.
 			// Make sure it behaves as though the fake module is vendored
 			// with no dependencies.
-			LoaderState.requirements.initVendor(nil)
+			loaderstate.requirements.initVendor(loaderstate, nil)
 		}
-		return LoaderState.requirements, nil
+		return loaderstate.requirements, nil
 	}
 
 	var modFiles []*modfile.File
 	var mainModules []module.Version
 	var indices []*modFileIndex
 	var errs []error
-	for _, modroot := range LoaderState.modRoots {
+	for _, modroot := range loaderstate.modRoots {
 		gomod := modFilePath(modroot)
 		var fixed bool
-		data, f, err := ReadModFile(gomod, fixVersion(ctx, &fixed))
+		data, f, err := ReadModFile(gomod, fixVersion(loaderstate, ctx, &fixed))
 		if err != nil {
-			if inWorkspaceMode() {
+			if inWorkspaceMode(loaderstate) {
 				if tooNew, ok := err.(*gover.TooNewError); ok && !strings.HasPrefix(cfg.CmdName, "work ") {
 					// Switching to a newer toolchain won't help - the go.work has the wrong version.
 					// Report this more specific error, unless we are a command like 'go work use'
@@ -981,7 +981,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			errs = append(errs, err)
 			continue
 		}
-		if inWorkspaceMode() && !strings.HasPrefix(cfg.CmdName, "work ") {
+		if inWorkspaceMode(loaderstate) && !strings.HasPrefix(cfg.CmdName, "work ") {
 			// Refuse to use workspace if its go version is too old.
 			// Disable this check if we are a workspace command like work use or work sync,
 			// which will fix the problem.
@@ -993,7 +993,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			}
 		}
 
-		if !inWorkspaceMode() {
+		if !inWorkspaceMode(loaderstate) {
 			ok := true
 			for _, g := range f.Godebug {
 				if err := CheckGodebug("godebug", g.Key, g.Value); err != nil {
@@ -1022,45 +1022,45 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		return nil, errors.Join(errs...)
 	}
 
-	LoaderState.MainModules = makeMainModules(mainModules, LoaderState.modRoots, modFiles, indices, workFile)
-	setDefaultBuildMod() // possibly enable automatic vendoring
-	rs := requirementsFromModFiles(ctx, workFile, modFiles, opts)
+	loaderstate.MainModules = makeMainModules(loaderstate, mainModules, loaderstate.modRoots, modFiles, indices, workFile)
+	setDefaultBuildMod(loaderstate) // possibly enable automatic vendoring
+	rs := requirementsFromModFiles(loaderstate, ctx, workFile, modFiles, opts)
 
 	if cfg.BuildMod == "vendor" {
-		readVendorList(VendorDir())
-		versions := LoaderState.MainModules.Versions()
+		readVendorList(VendorDir(loaderstate))
+		versions := loaderstate.MainModules.Versions()
 		indexes := make([]*modFileIndex, 0, len(versions))
 		modFiles := make([]*modfile.File, 0, len(versions))
 		modRoots := make([]string, 0, len(versions))
 		for _, m := range versions {
-			indexes = append(indexes, LoaderState.MainModules.Index(m))
-			modFiles = append(modFiles, LoaderState.MainModules.ModFile(m))
-			modRoots = append(modRoots, LoaderState.MainModules.ModRoot(m))
+			indexes = append(indexes, loaderstate.MainModules.Index(m))
+			modFiles = append(modFiles, loaderstate.MainModules.ModFile(m))
+			modRoots = append(modRoots, loaderstate.MainModules.ModRoot(m))
 		}
-		checkVendorConsistency(indexes, modFiles, modRoots)
-		rs.initVendor(vendorList)
+		checkVendorConsistency(loaderstate, indexes, modFiles, modRoots)
+		rs.initVendor(loaderstate, vendorList)
 	}
 
-	if inWorkspaceMode() {
+	if inWorkspaceMode(loaderstate) {
 		// We don't need to update the mod file so return early.
-		LoaderState.requirements = rs
+		loaderstate.requirements = rs
 		return rs, nil
 	}
 
-	mainModule := LoaderState.MainModules.mustGetSingleMainModule()
+	mainModule := loaderstate.MainModules.mustGetSingleMainModule(loaderstate)
 
-	if rs.hasRedundantRoot() {
+	if rs.hasRedundantRoot(loaderstate) {
 		// If any module path appears more than once in the roots, we know that the
 		// go.mod file needs to be updated even though we have not yet loaded any
 		// transitive dependencies.
 		var err error
-		rs, err = updateRoots(ctx, rs.direct, rs, nil, nil, false)
+		rs, err = updateRoots(loaderstate, ctx, rs.direct, rs, nil, nil, false)
 		if err != nil {
 			return nil, err
 		}
 	}
 
-	if LoaderState.MainModules.Index(mainModule).goVersion == "" && rs.pruning != workspace {
+	if loaderstate.MainModules.Index(mainModule).goVersion == "" && rs.pruning != workspace {
 		// TODO(#45551): Do something more principled instead of checking
 		// cfg.CmdName directly here.
 		if cfg.BuildMod == "mod" && cfg.CmdName != "mod graph" && cfg.CmdName != "mod why" {
@@ -1069,8 +1069,8 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			if opts != nil && opts.TidyGoVersion != "" {
 				v = opts.TidyGoVersion
 			}
-			addGoStmt(LoaderState.MainModules.ModFile(mainModule), mainModule, v)
-			rs = overrideRoots(ctx, rs, []module.Version{{Path: "go", Version: v}})
+			addGoStmt(loaderstate.MainModules.ModFile(mainModule), mainModule, v)
+			rs = overrideRoots(loaderstate, ctx, rs, []module.Version{{Path: "go", Version: v}})
 
 			// We need to add a 'go' version to the go.mod file, but we must assume
 			// that its existing contents match something between Go 1.11 and 1.16.
@@ -1079,7 +1079,7 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 			// requirements to support pruning.
 			if gover.Compare(v, gover.ExplicitIndirectVersion) >= 0 {
 				var err error
-				rs, err = convertPruning(ctx, rs, pruned)
+				rs, err = convertPruning(loaderstate, ctx, rs, pruned)
 				if err != nil {
 					return nil, err
 				}
@@ -1089,8 +1089,8 @@ func loadModFile(ctx context.Context, opts *PackageOpts) (*Requirements, error)
 		}
 	}
 
-	LoaderState.requirements = rs
-	return LoaderState.requirements, nil
+	loaderstate.requirements = rs
+	return loaderstate.requirements, nil
 }
 
 func errWorkTooOld(gomod string, wf *modfile.WorkFile, goVers string) error {
@@ -1126,7 +1126,7 @@ func CheckReservedModulePath(path string) error {
 func CreateModFile(ctx context.Context, modPath string) {
 	modRoot := base.Cwd()
 	LoaderState.modRoots = []string{modRoot}
-	Init()
+	Init(LoaderState)
 	modFilePath := modFilePath(modRoot)
 	if _, err := fsys.Stat(modFilePath); err == nil {
 		base.Fatalf("go: %s already exists", modFilePath)
@@ -1162,16 +1162,16 @@ func CreateModFile(ctx context.Context, modPath string) {
 	fmt.Fprintf(os.Stderr, "go: creating new go.mod: module %s\n", modPath)
 	modFile := new(modfile.File)
 	modFile.AddModuleStmt(modPath)
-	LoaderState.MainModules = makeMainModules([]module.Version{modFile.Module.Mod}, []string{modRoot}, []*modfile.File{modFile}, []*modFileIndex{nil}, nil)
+	LoaderState.MainModules = makeMainModules(LoaderState, []module.Version{modFile.Module.Mod}, []string{modRoot}, []*modfile.File{modFile}, []*modFileIndex{nil}, nil)
 	addGoStmt(modFile, modFile.Module.Mod, gover.Local()) // Add the go directive before converted module requirements.
 
-	rs := requirementsFromModFiles(ctx, nil, []*modfile.File{modFile}, nil)
-	rs, err := updateRoots(ctx, rs.direct, rs, nil, nil, false)
+	rs := requirementsFromModFiles(LoaderState, ctx, nil, []*modfile.File{modFile}, nil)
+	rs, err := updateRoots(LoaderState, ctx, rs.direct, rs, nil, nil, false)
 	if err != nil {
 		base.Fatal(err)
 	}
 	LoaderState.requirements = rs
-	if err := commitRequirements(ctx, WriteOpts{}); err != nil {
+	if err := commitRequirements(LoaderState, ctx, WriteOpts{}); err != nil {
 		base.Fatal(err)
 	}
 
@@ -1206,7 +1206,7 @@ func CreateModFile(ctx context.Context, modPath string) {
 // and does nothing for versions that already appear to be canonical.
 //
 // The VersionFixer sets 'fixed' if it ever returns a non-canonical version.
-func fixVersion(ctx context.Context, fixed *bool) modfile.VersionFixer {
+func fixVersion(loaderstate *State, ctx context.Context, fixed *bool) modfile.VersionFixer {
 	return func(path, vers string) (resolved string, err error) {
 		defer func() {
 			if err == nil && resolved != vers {
@@ -1239,7 +1239,7 @@ func fixVersion(ctx context.Context, fixed *bool) modfile.VersionFixer {
 			return vers, nil
 		}
 
-		info, err := Query(ctx, path, vers, "", nil)
+		info, err := Query(loaderstate, ctx, path, vers, "", nil)
 		if err != nil {
 			return "", err
 		}
@@ -1254,8 +1254,8 @@ func fixVersion(ctx context.Context, fixed *bool) modfile.VersionFixer {
 //
 // This function affects the default cfg.BuildMod when outside of a module,
 // so it can only be called prior to Init.
-func AllowMissingModuleImports() {
-	if LoaderState.initialized {
+func AllowMissingModuleImports(loaderstate *State) {
+	if loaderstate.initialized {
 		panic("AllowMissingModuleImports after Init")
 	}
 	allowMissingModuleImports = true
@@ -1263,7 +1263,7 @@ func AllowMissingModuleImports() {
 
 // makeMainModules creates a MainModuleSet and associated variables according to
 // the given main modules.
-func makeMainModules(ms []module.Version, rootDirs []string, modFiles []*modfile.File, indices []*modFileIndex, workFile *modfile.WorkFile) *MainModuleSet {
+func makeMainModules(loaderstate *State, ms []module.Version, rootDirs []string, modFiles []*modfile.File, indices []*modFileIndex, workFile *modfile.WorkFile) *MainModuleSet {
 	for _, m := range ms {
 		if m.Version != "" {
 			panic("mainModulesCalled with module.Version with non empty Version field: " + fmt.Sprintf("%#v", m))
@@ -1338,7 +1338,7 @@ func makeMainModules(ms []module.Version, rootDirs []string, modFiles []*modfile
 					continue
 				}
 				var newV module.Version = r.New
-				if WorkFilePath() != "" && newV.Version == "" && !filepath.IsAbs(newV.Path) {
+				if WorkFilePath(loaderstate) != "" && newV.Version == "" && !filepath.IsAbs(newV.Path) {
 					// Since we are in a workspace, we may be loading replacements from
 					// multiple go.mod files. Relative paths in those replacement are
 					// relative to the go.mod file, not the workspace, so the same string
@@ -1380,14 +1380,14 @@ func makeMainModules(ms []module.Version, rootDirs []string, modFiles []*modfile
 
 // requirementsFromModFiles returns the set of non-excluded requirements from
 // the global modFile.
-func requirementsFromModFiles(ctx context.Context, workFile *modfile.WorkFile, modFiles []*modfile.File, opts *PackageOpts) *Requirements {
+func requirementsFromModFiles(loaderstate *State, ctx context.Context, workFile *modfile.WorkFile, modFiles []*modfile.File, opts *PackageOpts) *Requirements {
 	var roots []module.Version
 	direct := map[string]bool{}
 	var pruning modPruning
-	if inWorkspaceMode() {
+	if inWorkspaceMode(loaderstate) {
 		pruning = workspace
-		roots = make([]module.Version, len(LoaderState.MainModules.Versions()), 2+len(LoaderState.MainModules.Versions()))
-		copy(roots, LoaderState.MainModules.Versions())
+		roots = make([]module.Version, len(loaderstate.MainModules.Versions()), 2+len(loaderstate.MainModules.Versions()))
+		copy(roots, loaderstate.MainModules.Versions())
 		goVersion := gover.FromGoWork(workFile)
 		var toolchain string
 		if workFile.Toolchain != nil {
@@ -1396,16 +1396,16 @@ func requirementsFromModFiles(ctx context.Context, workFile *modfile.WorkFile, m
 		roots = appendGoAndToolchainRoots(roots, goVersion, toolchain, direct)
 		direct = directRequirements(modFiles)
 	} else {
-		pruning = pruningForGoVersion(LoaderState.MainModules.GoVersion())
+		pruning = pruningForGoVersion(loaderstate.MainModules.GoVersion(loaderstate))
 		if len(modFiles) != 1 {
 			panic(fmt.Errorf("requirementsFromModFiles called with %v modfiles outside workspace mode", len(modFiles)))
 		}
 		modFile := modFiles[0]
-		roots, direct = rootsFromModFile(LoaderState.MainModules.mustGetSingleMainModule(), modFile, withToolchainRoot)
+		roots, direct = rootsFromModFile(loaderstate, loaderstate.MainModules.mustGetSingleMainModule(loaderstate), modFile, withToolchainRoot)
 	}
 
 	gover.ModSort(roots)
-	rs := newRequirements(pruning, roots, direct)
+	rs := newRequirements(loaderstate, pruning, roots, direct)
 	return rs
 }
 
@@ -1428,7 +1428,7 @@ func directRequirements(modFiles []*modfile.File) map[string]bool {
 	return direct
 }
 
-func rootsFromModFile(m module.Version, modFile *modfile.File, addToolchainRoot addToolchainRoot) (roots []module.Version, direct map[string]bool) {
+func rootsFromModFile(loaderstate *State, m module.Version, modFile *modfile.File, addToolchainRoot addToolchainRoot) (roots []module.Version, direct map[string]bool) {
 	direct = make(map[string]bool)
 	padding := 2 // Add padding for the toolchain and go version, added upon return.
 	if !addToolchainRoot {
@@ -1436,7 +1436,7 @@ func rootsFromModFile(m module.Version, modFile *modfile.File, addToolchainRoot
 	}
 	roots = make([]module.Version, 0, padding+len(modFile.Require))
 	for _, r := range modFile.Require {
-		if index := LoaderState.MainModules.Index(m); index != nil && index.exclude[r.Mod] {
+		if index := loaderstate.MainModules.Index(m); index != nil && index.exclude[r.Mod] {
 			if cfg.BuildMod == "mod" {
 				fmt.Fprintf(os.Stderr, "go: dropping requirement on excluded version %s %s\n", r.Mod.Path, r.Mod.Version)
 			} else {
@@ -1477,9 +1477,9 @@ func appendGoAndToolchainRoots(roots []module.Version, goVersion, toolchain stri
 
 // setDefaultBuildMod sets a default value for cfg.BuildMod if the -mod flag
 // wasn't provided. setDefaultBuildMod may be called multiple times.
-func setDefaultBuildMod() {
+func setDefaultBuildMod(loaderstate *State) {
 	if cfg.BuildModExplicit {
-		if inWorkspaceMode() && cfg.BuildMod != "readonly" && cfg.BuildMod != "vendor" {
+		if inWorkspaceMode(loaderstate) && cfg.BuildMod != "readonly" && cfg.BuildMod != "vendor" {
 			switch cfg.CmdName {
 			case "work sync", "mod graph", "mod verify", "mod why":
 				// These commands run with BuildMod set to mod, but they don't take the
@@ -1514,7 +1514,7 @@ func setDefaultBuildMod() {
 		cfg.BuildMod = "readonly"
 		return
 	}
-	if LoaderState.modRoots == nil {
+	if loaderstate.modRoots == nil {
 		if allowMissingModuleImports {
 			cfg.BuildMod = "mod"
 		} else {
@@ -1523,29 +1523,29 @@ func setDefaultBuildMod() {
 		return
 	}
 
-	if len(LoaderState.modRoots) >= 1 {
+	if len(loaderstate.modRoots) >= 1 {
 		var goVersion string
 		var versionSource string
-		if inWorkspaceMode() {
+		if inWorkspaceMode(loaderstate) {
 			versionSource = "go.work"
-			if wfg := LoaderState.MainModules.WorkFile().Go; wfg != nil {
+			if wfg := loaderstate.MainModules.WorkFile().Go; wfg != nil {
 				goVersion = wfg.Version
 			}
 		} else {
 			versionSource = "go.mod"
-			index := LoaderState.MainModules.GetSingleIndexOrNil()
+			index := loaderstate.MainModules.GetSingleIndexOrNil(loaderstate)
 			if index != nil {
 				goVersion = index.goVersion
 			}
 		}
 		vendorDir := ""
-		if LoaderState.workFilePath != "" {
-			vendorDir = filepath.Join(filepath.Dir(LoaderState.workFilePath), "vendor")
+		if loaderstate.workFilePath != "" {
+			vendorDir = filepath.Join(filepath.Dir(loaderstate.workFilePath), "vendor")
 		} else {
-			if len(LoaderState.modRoots) != 1 {
-				panic(fmt.Errorf("outside workspace mode, but have %v modRoots", LoaderState.modRoots))
+			if len(loaderstate.modRoots) != 1 {
+				panic(fmt.Errorf("outside workspace mode, but have %v modRoots", loaderstate.modRoots))
 			}
-			vendorDir = filepath.Join(LoaderState.modRoots[0], "vendor")
+			vendorDir = filepath.Join(loaderstate.modRoots[0], "vendor")
 		}
 		if fi, err := fsys.Stat(vendorDir); err == nil && fi.IsDir() {
 			if goVersion != "" {
@@ -1613,8 +1613,8 @@ func modulesTextIsForWorkspace(vendorDir string) (bool, error) {
 	return false, nil
 }
 
-func mustHaveCompleteRequirements() bool {
-	return cfg.BuildMod != "mod" && !inWorkspaceMode()
+func mustHaveCompleteRequirements(loaderstate *State) bool {
+	return cfg.BuildMod != "mod" && !inWorkspaceMode(loaderstate)
 }
 
 // addGoStmt adds a go directive to the go.mod file if it does not already
@@ -1809,21 +1809,21 @@ type WriteOpts struct {
 
 // WriteGoMod writes the current build list back to go.mod.
 func WriteGoMod(ctx context.Context, opts WriteOpts) error {
-	LoaderState.requirements = LoadModFile(ctx)
-	return commitRequirements(ctx, opts)
+	LoaderState.requirements = LoadModFile(LoaderState, ctx)
+	return commitRequirements(LoaderState, ctx, opts)
 }
 
 var errNoChange = errors.New("no update needed")
 
 // UpdateGoModFromReqs returns a modified go.mod file using the current
 // requirements. It does not commit these changes to disk.
-func UpdateGoModFromReqs(ctx context.Context, opts WriteOpts) (before, after []byte, modFile *modfile.File, err error) {
-	if LoaderState.MainModules.Len() != 1 || LoaderState.MainModules.ModRoot(LoaderState.MainModules.Versions()[0]) == "" {
+func UpdateGoModFromReqs(loaderstate *State, ctx context.Context, opts WriteOpts) (before, after []byte, modFile *modfile.File, err error) {
+	if loaderstate.MainModules.Len() != 1 || loaderstate.MainModules.ModRoot(loaderstate.MainModules.Versions()[0]) == "" {
 		// We aren't in a module, so we don't have anywhere to write a go.mod file.
 		return nil, nil, nil, errNoChange
 	}
-	mainModule := LoaderState.MainModules.mustGetSingleMainModule()
-	modFile = LoaderState.MainModules.ModFile(mainModule)
+	mainModule := loaderstate.MainModules.mustGetSingleMainModule(loaderstate)
+	modFile = loaderstate.MainModules.ModFile(mainModule)
 	if modFile == nil {
 		// command-line-arguments has no .mod file to write.
 		return nil, nil, nil, errNoChange
@@ -1836,7 +1836,7 @@ func UpdateGoModFromReqs(ctx context.Context, opts WriteOpts) (before, after []b
 	var list []*modfile.Require
 	toolchain := ""
 	goVersion := ""
-	for _, m := range LoaderState.requirements.rootModules {
+	for _, m := range loaderstate.requirements.rootModules {
 		if m.Path == "go" {
 			goVersion = m.Version
 			continue
@@ -1847,7 +1847,7 @@ func UpdateGoModFromReqs(ctx context.Context, opts WriteOpts) (before, after []b
 		}
 		list = append(list, &modfile.Require{
 			Mod:      m,
-			Indirect: !LoaderState.requirements.direct[m.Path],
+			Indirect: !loaderstate.requirements.direct[m.Path],
 		})
 	}
 
@@ -1917,13 +1917,13 @@ func UpdateGoModFromReqs(ctx context.Context, opts WriteOpts) (before, after []b
 // go.mod or go.sum are out of date in a semantically significant way.
 //
 // In workspace mode, commitRequirements only writes changes to go.work.sum.
-func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
-	if inWorkspaceMode() {
+func commitRequirements(loaderstate *State, ctx context.Context, opts WriteOpts) (err error) {
+	if inWorkspaceMode(loaderstate) {
 		// go.mod files aren't updated in workspace mode, but we still want to
 		// update the go.work.sum file.
-		return modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, LoaderState.requirements, addBuildListZipSums), mustHaveCompleteRequirements())
+		return modfetch.WriteGoSum(ctx, keepSums(loaderstate, ctx, loaded, loaderstate.requirements, addBuildListZipSums), mustHaveCompleteRequirements(loaderstate))
 	}
-	_, updatedGoMod, modFile, err := UpdateGoModFromReqs(ctx, opts)
+	_, updatedGoMod, modFile, err := UpdateGoModFromReqs(loaderstate, ctx, opts)
 	if err != nil {
 		if errors.Is(err, errNoChange) {
 			return nil
@@ -1931,7 +1931,7 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 		return err
 	}
 
-	index := LoaderState.MainModules.GetSingleIndexOrNil()
+	index := loaderstate.MainModules.GetSingleIndexOrNil(loaderstate)
 	dirty := index.modFileIsDirty(modFile) || len(opts.DropTools) > 0 || len(opts.AddTools) > 0
 	if dirty && cfg.BuildMod != "mod" {
 		// If we're about to fail due to -mod=readonly,
@@ -1945,15 +1945,15 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 		// Don't write go.mod, but write go.sum in case we added or trimmed sums.
 		// 'go mod init' shouldn't write go.sum, since it will be incomplete.
 		if cfg.CmdName != "mod init" {
-			if err := modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, LoaderState.requirements, addBuildListZipSums), mustHaveCompleteRequirements()); err != nil {
+			if err := modfetch.WriteGoSum(ctx, keepSums(loaderstate, ctx, loaded, loaderstate.requirements, addBuildListZipSums), mustHaveCompleteRequirements(loaderstate)); err != nil {
 				return err
 			}
 		}
 		return nil
 	}
 
-	mainModule := LoaderState.MainModules.mustGetSingleMainModule()
-	modFilePath := modFilePath(LoaderState.MainModules.ModRoot(mainModule))
+	mainModule := loaderstate.MainModules.mustGetSingleMainModule(loaderstate)
+	modFilePath := modFilePath(loaderstate.MainModules.ModRoot(mainModule))
 	if fsys.Replaced(modFilePath) {
 		if dirty {
 			return errors.New("updates to go.mod needed, but go.mod is part of the overlay specified with -overlay")
@@ -1962,13 +1962,13 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 	}
 	defer func() {
 		// At this point we have determined to make the go.mod file on disk equal to new.
-		LoaderState.MainModules.SetIndex(mainModule, indexModFile(updatedGoMod, modFile, mainModule, false))
+		loaderstate.MainModules.SetIndex(mainModule, indexModFile(updatedGoMod, modFile, mainModule, false))
 
 		// Update go.sum after releasing the side lock and refreshing the index.
 		// 'go mod init' shouldn't write go.sum, since it will be incomplete.
 		if cfg.CmdName != "mod init" {
 			if err == nil {
-				err = modfetch.WriteGoSum(ctx, keepSums(ctx, loaded, LoaderState.requirements, addBuildListZipSums), mustHaveCompleteRequirements())
+				err = modfetch.WriteGoSum(ctx, keepSums(loaderstate, ctx, loaded, loaderstate.requirements, addBuildListZipSums), mustHaveCompleteRequirements(loaderstate))
 			}
 		}
 	}()
@@ -2011,7 +2011,7 @@ func commitRequirements(ctx context.Context, opts WriteOpts) (err error) {
 // including any go.mod files needed to reconstruct the MVS result
 // or identify go versions,
 // in addition to the checksums for every module in keepMods.
-func keepSums(ctx context.Context, ld *loader, rs *Requirements, which whichSums) map[module.Version]bool {
+func keepSums(loaderstate *State, ctx context.Context, ld *loader, rs *Requirements, which whichSums) map[module.Version]bool {
 	// Every module in the full module graph contributes its requirements,
 	// so in order to ensure that the build list itself is reproducible,
 	// we need sums for every go.mod in the graph (regardless of whether
@@ -2024,12 +2024,12 @@ func keepSums(ctx context.Context, ld *loader, rs *Requirements, which whichSums
 	// ambiguous import errors the next time we load the package.
 	keepModSumsForZipSums := true
 	if ld == nil {
-		if gover.Compare(LoaderState.MainModules.GoVersion(), gover.TidyGoModSumVersion) < 0 && cfg.BuildMod != "mod" {
+		if gover.Compare(loaderstate.MainModules.GoVersion(loaderstate), gover.TidyGoModSumVersion) < 0 && cfg.BuildMod != "mod" {
 			keepModSumsForZipSums = false
 		}
 	} else {
 		keepPkgGoModSums := true
-		if gover.Compare(ld.requirements.GoVersion(), gover.TidyGoModSumVersion) < 0 && (ld.Tidy || cfg.BuildMod != "mod") {
+		if gover.Compare(ld.requirements.GoVersion(loaderstate), gover.TidyGoModSumVersion) < 0 && (ld.Tidy || cfg.BuildMod != "mod") {
 			keepPkgGoModSums = false
 			keepModSumsForZipSums = false
 		}
@@ -2047,21 +2047,21 @@ func keepSums(ctx context.Context, ld *loader, rs *Requirements, which whichSums
 			// minor, so we maintain the previous (buggy) behavior in 'go mod tidy' to
 			// avoid introducing unnecessary churn.
 			if keepPkgGoModSums {
-				r := resolveReplacement(pkg.mod)
+				r := resolveReplacement(loaderstate, pkg.mod)
 				keep[modkey(r)] = true
 			}
 
 			if rs.pruning == pruned && pkg.mod.Path != "" {
-				if v, ok := rs.rootSelected(pkg.mod.Path); ok && v == pkg.mod.Version {
+				if v, ok := rs.rootSelected(loaderstate, pkg.mod.Path); ok && v == pkg.mod.Version {
 					// pkg was loaded from a root module, and because the main module has
 					// a pruned module graph we do not check non-root modules for
 					// conflicts for packages that can be found in roots. So we only need
 					// the checksums for the root modules that may contain pkg, not all
 					// possible modules.
 					for prefix := pkg.path; prefix != "."; prefix = path.Dir(prefix) {
-						if v, ok := rs.rootSelected(prefix); ok && v != "none" {
+						if v, ok := rs.rootSelected(loaderstate, prefix); ok && v != "none" {
 							m := module.Version{Path: prefix, Version: v}
-							r := resolveReplacement(m)
+							r := resolveReplacement(loaderstate, m)
 							keep[r] = true
 						}
 					}
@@ -2069,11 +2069,11 @@ func keepSums(ctx context.Context, ld *loader, rs *Requirements, which whichSums
 				}
 			}
 
-			mg, _ := rs.Graph(ctx)
+			mg, _ := rs.Graph(loaderstate, ctx)
 			for prefix := pkg.path; prefix != "."; prefix = path.Dir(prefix) {
 				if v := mg.Selected(prefix); v != "none" {
 					m := module.Version{Path: prefix, Version: v}
-					r := resolveReplacement(m)
+					r := resolveReplacement(loaderstate, m)
 					keep[r] = true
 				}
 			}
@@ -2085,27 +2085,27 @@ func keepSums(ctx context.Context, ld *loader, rs *Requirements, which whichSums
 		// Save sums for the root modules (or their replacements), but don't
 		// incur the cost of loading the graph just to find and retain the sums.
 		for _, m := range rs.rootModules {
-			r := resolveReplacement(m)
+			r := resolveReplacement(loaderstate, m)
 			keep[modkey(r)] = true
 			if which == addBuildListZipSums {
 				keep[r] = true
 			}
 		}
 	} else {
-		mg, _ := rs.Graph(ctx)
+		mg, _ := rs.Graph(loaderstate, ctx)
 		mg.WalkBreadthFirst(func(m module.Version) {
 			if _, ok := mg.RequiredBy(m); ok {
 				// The requirements from m's go.mod file are present in the module graph,
 				// so they are relevant to the MVS result regardless of whether m was
 				// actually selected.
-				r := resolveReplacement(m)
+				r := resolveReplacement(loaderstate, m)
 				keep[modkey(r)] = true
 			}
 		})
 
 		if which == addBuildListZipSums {
 			for _, m := range mg.BuildList() {
-				r := resolveReplacement(m)
+				r := resolveReplacement(loaderstate, m)
 				if keepModSumsForZipSums {
 					keep[modkey(r)] = true // we need the go version from the go.mod file to do anything useful with the zipfile
 				}
diff --git a/src/cmd/go/internal/modload/list.go b/src/cmd/go/internal/modload/list.go
index 803bab49ae96bb..bd28d7596e160a 100644
--- a/src/cmd/go/internal/modload/list.go
+++ b/src/cmd/go/internal/modload/list.go
@@ -69,7 +69,7 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 		}
 	}
 
-	rs, mods, err := listModules(ctx, LoadModFile(ctx), args, mode, reuse)
+	rs, mods, err := listModules(ctx, LoadModFile(LoaderState, ctx), args, mode, reuse)
 
 	type token struct{}
 	sem := make(chan token, runtime.GOMAXPROCS(0))
@@ -88,7 +88,7 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 						addVersions(ctx, m, mode&ListRetractedVersions != 0)
 					}
 					if mode&ListRetracted != 0 {
-						addRetraction(ctx, m)
+						addRetraction(LoaderState, ctx, m)
 					}
 					if mode&ListDeprecated != 0 {
 						addDeprecation(ctx, m)
@@ -117,7 +117,7 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 		// but in general list -u is looking up other checksums in the checksum database
 		// that won't be necessary later, so it makes sense not to write the go.sum back out.
 		if !ExplicitWriteGoMod && mode&ListU == 0 {
-			err = commitRequirements(ctx, WriteOpts{})
+			err = commitRequirements(LoaderState, ctx, WriteOpts{})
 		}
 	}
 	return mods, err
@@ -130,7 +130,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 			if gover.IsToolchain(m.Path) {
 				continue
 			}
-			ms = append(ms, moduleInfo(ctx, rs, m, mode, reuse))
+			ms = append(ms, moduleInfo(LoaderState, ctx, rs, m, mode, reuse))
 		}
 		return rs, ms, nil
 	}
@@ -145,25 +145,25 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 		}
 		if arg == "all" || strings.Contains(arg, "...") {
 			needFullGraph = true
-			if !HasModRoot() {
+			if !HasModRoot(LoaderState) {
 				base.Fatalf("go: cannot match %q: %v", arg, ErrNoModRoot)
 			}
 			continue
 		}
 		if path, vers, found := strings.Cut(arg, "@"); found {
 			if vers == "upgrade" || vers == "patch" {
-				if _, ok := rs.rootSelected(path); !ok || rs.pruning == unpruned {
+				if _, ok := rs.rootSelected(LoaderState, path); !ok || rs.pruning == unpruned {
 					needFullGraph = true
-					if !HasModRoot() {
+					if !HasModRoot(LoaderState) {
 						base.Fatalf("go: cannot match %q: %v", arg, ErrNoModRoot)
 					}
 				}
 			}
 			continue
 		}
-		if _, ok := rs.rootSelected(arg); !ok || rs.pruning == unpruned {
+		if _, ok := rs.rootSelected(LoaderState, arg); !ok || rs.pruning == unpruned {
 			needFullGraph = true
-			if mode&ListVersions == 0 && !HasModRoot() {
+			if mode&ListVersions == 0 && !HasModRoot(LoaderState) {
 				base.Fatalf("go: cannot match %q without -versions or an explicit version: %v", arg, ErrNoModRoot)
 			}
 		}
@@ -171,7 +171,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 
 	var mg *ModuleGraph
 	if needFullGraph {
-		rs, mg, mgErr = expandGraph(ctx, rs)
+		rs, mg, mgErr = expandGraph(LoaderState, ctx, rs)
 	}
 
 	matchedModule := map[module.Version]bool{}
@@ -179,7 +179,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 		if path, vers, found := strings.Cut(arg, "@"); found {
 			var current string
 			if mg == nil {
-				current, _ = rs.rootSelected(path)
+				current, _ = rs.rootSelected(LoaderState, path)
 			} else {
 				current = mg.Selected(path)
 			}
@@ -198,7 +198,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 				// specific revision or used 'go list -retracted'.
 				allowed = nil
 			}
-			info, err := queryReuse(ctx, path, vers, current, allowed, reuse)
+			info, err := queryReuse(LoaderState, ctx, path, vers, current, allowed, reuse)
 			if err != nil {
 				var origin *codehost.Origin
 				if info != nil {
@@ -217,7 +217,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 			// *Requirements instead.
 			var noRS *Requirements
 
-			mod := moduleInfo(ctx, noRS, module.Version{Path: path, Version: info.Version}, mode, reuse)
+			mod := moduleInfo(LoaderState, ctx, noRS, module.Version{Path: path, Version: info.Version}, mode, reuse)
 			if vers != mod.Version {
 				mod.Query = vers
 			}
@@ -237,7 +237,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 			var v string
 			if mg == nil {
 				var ok bool
-				v, ok = rs.rootSelected(arg)
+				v, ok = rs.rootSelected(LoaderState, arg)
 				if !ok {
 					// We checked rootSelected(arg) in the earlier args loop, so if there
 					// is no such root we should have loaded a non-nil mg.
@@ -251,7 +251,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 				continue
 			}
 			if v != "none" {
-				mods = append(mods, moduleInfo(ctx, rs, module.Version{Path: arg, Version: v}, mode, reuse))
+				mods = append(mods, moduleInfo(LoaderState, ctx, rs, module.Version{Path: arg, Version: v}, mode, reuse))
 			} else if cfg.BuildMod == "vendor" {
 				// In vendor mode, we can't determine whether a missing module is “a
 				// known dependency” because the module graph is incomplete.
@@ -292,7 +292,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 		fetchedMods := make([]*modinfo.ModulePublic, len(matches))
 		for i, m := range matches {
 			q.Add(func() {
-				fetchedMods[i] = moduleInfo(ctx, rs, m, mode, reuse)
+				fetchedMods[i] = moduleInfo(LoaderState, ctx, rs, m, mode, reuse)
 			})
 		}
 		<-q.Idle()
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index 0d661eb2e7b0be..ad3b80bfd954aa 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -250,7 +250,7 @@ type PackageOpts struct {
 
 // LoadPackages identifies the set of packages matching the given patterns and
 // loads the packages in the import graph rooted at that set.
-func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (matches []*search.Match, loadedPackages []string) {
+func LoadPackages(loaderstate *State, ctx context.Context, opts PackageOpts, patterns ...string) (matches []*search.Match, loadedPackages []string) {
 	if opts.Tags == nil {
 		opts.Tags = imports.Tags()
 	}
@@ -271,11 +271,11 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 			case m.IsLocal():
 				// Evaluate list of file system directories on first iteration.
 				if m.Dirs == nil {
-					matchModRoots := LoaderState.modRoots
+					matchModRoots := loaderstate.modRoots
 					if opts.MainModule != (module.Version{}) {
-						matchModRoots = []string{LoaderState.MainModules.ModRoot(opts.MainModule)}
+						matchModRoots = []string{loaderstate.MainModules.ModRoot(opts.MainModule)}
 					}
-					matchLocalDirs(ctx, matchModRoots, m, rs)
+					matchLocalDirs(loaderstate, ctx, matchModRoots, m, rs)
 				}
 
 				// Make a copy of the directory list and translate to import paths.
@@ -286,7 +286,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 				// the loader iterations.
 				m.Pkgs = m.Pkgs[:0]
 				for _, dir := range m.Dirs {
-					pkg, err := resolveLocalPackage(ctx, dir, rs)
+					pkg, err := resolveLocalPackage(loaderstate, ctx, dir, rs)
 					if err != nil {
 						if !m.IsLiteral() && (err == errPkgIsBuiltin || err == errPkgIsGorootSrc) {
 							continue // Don't include "builtin" or GOROOT/src in wildcard patterns.
@@ -294,8 +294,8 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 
 						// If we're outside of a module, ensure that the failure mode
 						// indicates that.
-						if !HasModRoot() {
-							die()
+						if !HasModRoot(loaderstate) {
+							die(loaderstate)
 						}
 
 						if ld != nil {
@@ -311,7 +311,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 
 			case strings.Contains(m.Pattern(), "..."):
 				m.Errs = m.Errs[:0]
-				mg, err := rs.Graph(ctx)
+				mg, err := rs.Graph(loaderstate, ctx)
 				if err != nil {
 					// The module graph is (or may be) incomplete — perhaps we failed to
 					// load the requirements of some module. This is an error in matching
@@ -321,26 +321,26 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 					// necessarily prevent us from loading the packages we could find.
 					m.Errs = append(m.Errs, err)
 				}
-				matchPackages(ctx, m, opts.Tags, includeStd, mg.BuildList())
+				matchPackages(loaderstate, ctx, m, opts.Tags, includeStd, mg.BuildList())
 
 			case m.Pattern() == "work":
-				matchModules := LoaderState.MainModules.Versions()
+				matchModules := loaderstate.MainModules.Versions()
 				if opts.MainModule != (module.Version{}) {
 					matchModules = []module.Version{opts.MainModule}
 				}
-				matchPackages(ctx, m, opts.Tags, omitStd, matchModules)
+				matchPackages(loaderstate, ctx, m, opts.Tags, omitStd, matchModules)
 
 			case m.Pattern() == "all":
 				if ld == nil {
 					// The initial roots are the packages and tools in the main module.
 					// loadFromRoots will expand that to "all".
 					m.Errs = m.Errs[:0]
-					matchModules := LoaderState.MainModules.Versions()
+					matchModules := loaderstate.MainModules.Versions()
 					if opts.MainModule != (module.Version{}) {
 						matchModules = []module.Version{opts.MainModule}
 					}
-					matchPackages(ctx, m, opts.Tags, omitStd, matchModules)
-					for tool := range LoaderState.MainModules.Tools() {
+					matchPackages(loaderstate, ctx, m, opts.Tags, omitStd, matchModules)
+					for tool := range loaderstate.MainModules.Tools() {
 						m.Pkgs = append(m.Pkgs, tool)
 					}
 				} else {
@@ -355,7 +355,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 				}
 
 			case m.Pattern() == "tool":
-				for tool := range LoaderState.MainModules.Tools() {
+				for tool := range loaderstate.MainModules.Tools() {
 					m.Pkgs = append(m.Pkgs, tool)
 				}
 			default:
@@ -364,12 +364,12 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 		}
 	}
 
-	initialRS, err := loadModFile(ctx, &opts)
+	initialRS, err := loadModFile(loaderstate, ctx, &opts)
 	if err != nil {
 		base.Fatal(err)
 	}
 
-	ld := loadFromRoots(ctx, loaderParams{
+	ld := loadFromRoots(loaderstate, ctx, loaderParams{
 		PackageOpts:  opts,
 		requirements: initialRS,
 
@@ -404,7 +404,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 
 	if opts.Tidy {
 		if cfg.BuildV {
-			mg, _ := ld.requirements.Graph(ctx)
+			mg, _ := ld.requirements.Graph(loaderstate, ctx)
 			for _, m := range initialRS.rootModules {
 				var unused bool
 				if ld.requirements.pruning == unpruned {
@@ -416,7 +416,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 					// m is unused if it was dropped from the roots. If it is still present
 					// as a transitive dependency, that transitive dependency is not needed
 					// by any package or test in the main module.
-					_, ok := ld.requirements.rootSelected(m.Path)
+					_, ok := ld.requirements.rootSelected(loaderstate, m.Path)
 					unused = !ok
 				}
 				if unused {
@@ -425,9 +425,9 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 			}
 		}
 
-		keep := keepSums(ctx, ld, ld.requirements, loadedZipSumsOnly)
+		keep := keepSums(loaderstate, ctx, ld, ld.requirements, loadedZipSumsOnly)
 		compatVersion := ld.TidyCompatibleVersion
-		goVersion := ld.requirements.GoVersion()
+		goVersion := ld.requirements.GoVersion(loaderstate)
 		if compatVersion == "" {
 			if gover.Compare(goVersion, gover.GoStrictVersion) < 0 {
 				compatVersion = gover.Prev(goVersion)
@@ -444,10 +444,10 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 			compatVersion = goVersion
 		}
 		if compatPruning := pruningForGoVersion(compatVersion); compatPruning != ld.requirements.pruning {
-			compatRS := newRequirements(compatPruning, ld.requirements.rootModules, ld.requirements.direct)
-			ld.checkTidyCompatibility(ctx, compatRS, compatVersion)
+			compatRS := newRequirements(loaderstate, compatPruning, ld.requirements.rootModules, ld.requirements.direct)
+			ld.checkTidyCompatibility(loaderstate, ctx, compatRS, compatVersion)
 
-			for m := range keepSums(ctx, ld, compatRS, loadedZipSumsOnly) {
+			for m := range keepSums(loaderstate, ctx, ld, compatRS, loadedZipSumsOnly) {
 				keep[m] = true
 			}
 		}
@@ -455,8 +455,8 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 		if opts.TidyDiff {
 			cfg.BuildMod = "readonly"
 			loaded = ld
-			LoaderState.requirements = loaded.requirements
-			currentGoMod, updatedGoMod, _, err := UpdateGoModFromReqs(ctx, WriteOpts{})
+			loaderstate.requirements = loaded.requirements
+			currentGoMod, updatedGoMod, _, err := UpdateGoModFromReqs(loaderstate, ctx, WriteOpts{})
 			if err != nil {
 				base.Fatal(err)
 			}
@@ -466,7 +466,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 			// Dropping compatibility for 1.16 may result in a strictly smaller go.sum.
 			// Update the keep map with only the loaded.requirements.
 			if gover.Compare(compatVersion, "1.16") > 0 {
-				keep = keepSums(ctx, loaded, LoaderState.requirements, addBuildListZipSums)
+				keep = keepSums(loaderstate, ctx, loaded, loaderstate.requirements, addBuildListZipSums)
 			}
 			currentGoSum, tidyGoSum := modfetch.TidyGoSum(keep)
 			goSumDiff := diff.Diff("current/go.sum", currentGoSum, "tidy/go.sum", tidyGoSum)
@@ -490,7 +490,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 			// loaded.requirements, but here we may have also loaded (and want to
 			// preserve checksums for) additional entities from compatRS, which are
 			// only needed for compatibility with ld.TidyCompatibleVersion.
-			if err := modfetch.WriteGoSum(ctx, keep, mustHaveCompleteRequirements()); err != nil {
+			if err := modfetch.WriteGoSum(ctx, keep, mustHaveCompleteRequirements(loaderstate)); err != nil {
 				base.Fatal(err)
 			}
 		}
@@ -505,7 +505,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 	// to call WriteGoMod itself) or if ResolveMissingImports is false (the
 	// command wants to examine the package graph as-is).
 	loaded = ld
-	LoaderState.requirements = loaded.requirements
+	loaderstate.requirements = loaded.requirements
 
 	for _, pkg := range ld.pkgs {
 		if !pkg.isTest() {
@@ -515,7 +515,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 	sort.Strings(loadedPackages)
 
 	if !ExplicitWriteGoMod && opts.ResolveMissingImports {
-		if err := commitRequirements(ctx, WriteOpts{}); err != nil {
+		if err := commitRequirements(loaderstate, ctx, WriteOpts{}); err != nil {
 			base.Fatal(err)
 		}
 	}
@@ -525,7 +525,7 @@ func LoadPackages(ctx context.Context, opts PackageOpts, patterns ...string) (ma
 
 // matchLocalDirs is like m.MatchDirs, but tries to avoid scanning directories
 // outside of the standard library and active modules.
-func matchLocalDirs(ctx context.Context, modRoots []string, m *search.Match, rs *Requirements) {
+func matchLocalDirs(loaderstate *State, ctx context.Context, modRoots []string, m *search.Match, rs *Requirements) {
 	if !m.IsLocal() {
 		panic(fmt.Sprintf("internal error: resolveLocalDirs on non-local pattern %s", m.Pattern()))
 	}
@@ -543,10 +543,10 @@ func matchLocalDirs(ctx context.Context, modRoots []string, m *search.Match, rs
 		}
 
 		modRoot := findModuleRoot(absDir)
-		if !slices.Contains(modRoots, modRoot) && search.InDir(absDir, cfg.GOROOTsrc) == "" && pathInModuleCache(ctx, absDir, rs) == "" {
+		if !slices.Contains(modRoots, modRoot) && search.InDir(absDir, cfg.GOROOTsrc) == "" && pathInModuleCache(loaderstate, ctx, absDir, rs) == "" {
 			m.Dirs = []string{}
 			scope := "main module or its selected dependencies"
-			if inWorkspaceMode() {
+			if inWorkspaceMode(loaderstate) {
 				scope = "modules listed in go.work or their selected dependencies"
 			}
 			m.AddError(fmt.Errorf("directory prefix %s does not contain %s", base.ShortPath(absDir), scope))
@@ -558,7 +558,7 @@ func matchLocalDirs(ctx context.Context, modRoots []string, m *search.Match, rs
 }
 
 // resolveLocalPackage resolves a filesystem path to a package path.
-func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (string, error) {
+func resolveLocalPackage(loaderstate *State, ctx context.Context, dir string, rs *Requirements) (string, error) {
 	var absDir string
 	if filepath.IsAbs(dir) {
 		absDir = filepath.Clean(dir)
@@ -596,13 +596,13 @@ func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (str
 		}
 	}
 
-	for _, mod := range LoaderState.MainModules.Versions() {
-		modRoot := LoaderState.MainModules.ModRoot(mod)
+	for _, mod := range loaderstate.MainModules.Versions() {
+		modRoot := loaderstate.MainModules.ModRoot(mod)
 		if modRoot != "" && absDir == modRoot {
 			if absDir == cfg.GOROOTsrc {
 				return "", errPkgIsGorootSrc
 			}
-			return LoaderState.MainModules.PathPrefix(mod), nil
+			return loaderstate.MainModules.PathPrefix(mod), nil
 		}
 	}
 
@@ -611,8 +611,8 @@ func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (str
 	// It's not strictly necessary but helpful to keep the checks.
 	var pkgNotFoundErr error
 	pkgNotFoundLongestPrefix := ""
-	for _, mainModule := range LoaderState.MainModules.Versions() {
-		modRoot := LoaderState.MainModules.ModRoot(mainModule)
+	for _, mainModule := range loaderstate.MainModules.Versions() {
+		modRoot := loaderstate.MainModules.ModRoot(mainModule)
 		if modRoot != "" && str.HasFilePathPrefix(absDir, modRoot) && !strings.Contains(absDir[len(modRoot):], "@") {
 			suffix := filepath.ToSlash(str.TrimFilePathPrefix(absDir, modRoot))
 			if pkg, found := strings.CutPrefix(suffix, "vendor/"); found {
@@ -620,14 +620,14 @@ func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (str
 					return "", fmt.Errorf("without -mod=vendor, directory %s has no package path", absDir)
 				}
 
-				readVendorList(VendorDir())
+				readVendorList(VendorDir(loaderstate))
 				if _, ok := vendorPkgModule[pkg]; !ok {
 					return "", fmt.Errorf("directory %s is not a package listed in vendor/modules.txt", absDir)
 				}
 				return pkg, nil
 			}
 
-			mainModulePrefix := LoaderState.MainModules.PathPrefix(mainModule)
+			mainModulePrefix := loaderstate.MainModules.PathPrefix(mainModule)
 			if mainModulePrefix == "" {
 				pkg := suffix
 				if pkg == "builtin" {
@@ -668,13 +668,13 @@ func resolveLocalPackage(ctx context.Context, dir string, rs *Requirements) (str
 		return pkg, nil
 	}
 
-	pkg := pathInModuleCache(ctx, absDir, rs)
+	pkg := pathInModuleCache(loaderstate, ctx, absDir, rs)
 	if pkg == "" {
 		dirstr := fmt.Sprintf("directory %s", base.ShortPath(absDir))
 		if dirstr == "directory ." {
 			dirstr = "current directory"
 		}
-		if inWorkspaceMode() {
+		if inWorkspaceMode(loaderstate) {
 			if mr := findModuleRoot(absDir); mr != "" {
 				return "", fmt.Errorf("%s is contained in a module that is not one of the workspace modules listed in go.work. You can add the module to the workspace using:\n\tgo work use %s", dirstr, base.ShortPath(mr))
 			}
@@ -693,17 +693,17 @@ var (
 
 // pathInModuleCache returns the import path of the directory dir,
 // if dir is in the module cache copy of a module in our build list.
-func pathInModuleCache(ctx context.Context, dir string, rs *Requirements) string {
+func pathInModuleCache(loaderstate *State, ctx context.Context, dir string, rs *Requirements) string {
 	tryMod := func(m module.Version) (string, bool) {
 		if gover.IsToolchain(m.Path) {
 			return "", false
 		}
 		var root string
 		var err error
-		if repl := Replacement(m); repl.Path != "" && repl.Version == "" {
+		if repl := Replacement(loaderstate, m); repl.Path != "" && repl.Version == "" {
 			root = repl.Path
 			if !filepath.IsAbs(root) {
-				root = filepath.Join(replaceRelativeTo(), root)
+				root = filepath.Join(replaceRelativeTo(loaderstate), root)
 			}
 		} else if repl.Path != "" {
 			root, err = modfetch.DownloadDir(ctx, repl)
@@ -728,7 +728,7 @@ func pathInModuleCache(ctx context.Context, dir string, rs *Requirements) string
 
 	if rs.pruning == pruned {
 		for _, m := range rs.rootModules {
-			if v, _ := rs.rootSelected(m.Path); v != m.Version {
+			if v, _ := rs.rootSelected(loaderstate, m.Path); v != m.Version {
 				continue // m is a root, but we have a higher root for the same path.
 			}
 			if importPath, ok := tryMod(m); ok {
@@ -747,7 +747,7 @@ func pathInModuleCache(ctx context.Context, dir string, rs *Requirements) string
 	// versions of root modules may differ from what we already checked above.
 	// Re-check those paths too.
 
-	mg, _ := rs.Graph(ctx)
+	mg, _ := rs.Graph(loaderstate, ctx)
 	var importPath string
 	for _, m := range mg.BuildList() {
 		var found bool
@@ -766,8 +766,8 @@ func pathInModuleCache(ctx context.Context, dir string, rs *Requirements) string
 //
 // TODO(bcmills): Silencing errors seems off. Take a closer look at this and
 // figure out what the error-reporting actually ought to be.
-func ImportFromFiles(ctx context.Context, gofiles []string) {
-	rs := LoadModFile(ctx)
+func ImportFromFiles(loaderstate *State, ctx context.Context, gofiles []string) {
+	rs := LoadModFile(loaderstate, ctx)
 
 	tags := imports.Tags()
 	imports, testImports, err := imports.ScanFiles(gofiles, tags)
@@ -775,7 +775,7 @@ func ImportFromFiles(ctx context.Context, gofiles []string) {
 		base.Fatal(err)
 	}
 
-	loaded = loadFromRoots(ctx, loaderParams{
+	loaded = loadFromRoots(loaderstate, ctx, loaderParams{
 		PackageOpts: PackageOpts{
 			Tags:                  tags,
 			ResolveMissingImports: true,
@@ -788,10 +788,10 @@ func ImportFromFiles(ctx context.Context, gofiles []string) {
 			return roots
 		},
 	})
-	LoaderState.requirements = loaded.requirements
+	loaderstate.requirements = loaded.requirements
 
 	if !ExplicitWriteGoMod {
-		if err := commitRequirements(ctx, WriteOpts{}); err != nil {
+		if err := commitRequirements(loaderstate, ctx, WriteOpts{}); err != nil {
 			base.Fatal(err)
 		}
 	}
@@ -799,11 +799,11 @@ func ImportFromFiles(ctx context.Context, gofiles []string) {
 
 // DirImportPath returns the effective import path for dir,
 // provided it is within a main module, or else returns ".".
-func (mms *MainModuleSet) DirImportPath(ctx context.Context, dir string) (path string, m module.Version) {
-	if !HasModRoot() {
+func (mms *MainModuleSet) DirImportPath(loaderstate *State, ctx context.Context, dir string) (path string, m module.Version) {
+	if !HasModRoot(loaderstate) {
 		return ".", module.Version{}
 	}
-	LoadModFile(ctx) // Sets targetPrefix.
+	LoadModFile(loaderstate, ctx) // Sets targetPrefix.
 
 	if !filepath.IsAbs(dir) {
 		dir = filepath.Join(base.Cwd(), dir)
@@ -820,7 +820,7 @@ func (mms *MainModuleSet) DirImportPath(ctx context.Context, dir string) (path s
 			return mms.PathPrefix(v), v
 		}
 		if str.HasFilePathPrefix(dir, modRoot) {
-			pathPrefix := LoaderState.MainModules.PathPrefix(v)
+			pathPrefix := loaderstate.MainModules.PathPrefix(v)
 			if pathPrefix > longestPrefix {
 				longestPrefix = pathPrefix
 				longestPrefixVersion = v
@@ -853,13 +853,13 @@ func PackageModule(path string) module.Version {
 // the package at path as imported from the package in parentDir.
 // Lookup requires that one of the Load functions in this package has already
 // been called.
-func Lookup(parentPath string, parentIsStd bool, path string) (dir, realPath string, err error) {
+func Lookup(loaderstate *State, parentPath string, parentIsStd bool, path string) (dir, realPath string, err error) {
 	if path == "" {
 		panic("Lookup called with empty package path")
 	}
 
 	if parentIsStd {
-		path = loaded.stdVendor(parentPath, path)
+		path = loaded.stdVendor(loaderstate, parentPath, path)
 	}
 	pkg, ok := loaded.pkgCache.Get(path)
 	if !ok {
@@ -957,11 +957,11 @@ func (ld *loader) exitIfErrors(ctx context.Context) {
 // goVersion reports the Go version that should be used for the loader's
 // requirements: ld.TidyGoVersion if set, or ld.requirements.GoVersion()
 // otherwise.
-func (ld *loader) goVersion() string {
+func (ld *loader) goVersion(loaderstate *State) string {
 	if ld.TidyGoVersion != "" {
 		return ld.TidyGoVersion
 	}
-	return ld.requirements.GoVersion()
+	return ld.requirements.GoVersion(loaderstate)
 }
 
 // A loadPkg records information about a single loaded package.
@@ -1064,11 +1064,11 @@ func (pkg *loadPkg) isTest() bool {
 
 // fromExternalModule reports whether pkg was loaded from a module other than
 // the main module.
-func (pkg *loadPkg) fromExternalModule() bool {
+func (pkg *loadPkg) fromExternalModule(loaderstate *State) bool {
 	if pkg.mod.Path == "" {
 		return false // loaded from the standard library, not a module
 	}
-	return !LoaderState.MainModules.Contains(pkg.mod.Path)
+	return !loaderstate.MainModules.Contains(pkg.mod.Path)
 }
 
 var errMissing = errors.New("cannot find package")
@@ -1079,7 +1079,7 @@ var errMissing = errors.New("cannot find package")
 // The set of root packages is returned by the params.listRoots function, and
 // expanded to the full set of packages by tracing imports (and possibly tests)
 // as needed.
-func loadFromRoots(ctx context.Context, params loaderParams) *loader {
+func loadFromRoots(loaderstate *State, ctx context.Context, params loaderParams) *loader {
 	ld := &loader{
 		loaderParams: params,
 		work:         par.NewQueue(runtime.GOMAXPROCS(0)),
@@ -1095,7 +1095,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 		// spot-checks in modules that do not maintain the expanded go.mod
 		// requirements needed for graph pruning.
 		var err error
-		ld.requirements, _, err = expandGraph(ctx, ld.requirements)
+		ld.requirements, _, err = expandGraph(loaderstate, ctx, ld.requirements)
 		if err != nil {
 			ld.error(err)
 		}
@@ -1103,11 +1103,11 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 	ld.exitIfErrors(ctx)
 
 	updateGoVersion := func() {
-		goVersion := ld.goVersion()
+		goVersion := ld.goVersion(loaderstate)
 
 		if ld.requirements.pruning != workspace {
 			var err error
-			ld.requirements, err = convertPruning(ctx, ld.requirements, pruningForGoVersion(goVersion))
+			ld.requirements, err = convertPruning(loaderstate, ctx, ld.requirements, pruningForGoVersion(goVersion))
 			if err != nil {
 				ld.error(err)
 				ld.exitIfErrors(ctx)
@@ -1141,7 +1141,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 			// set of root packages does not change then we can select the correct
 			// versions of all transitive imports on the first try and complete
 			// loading in a single iteration.
-			changedBuildList := ld.preloadRootModules(ctx, rootPkgs)
+			changedBuildList := ld.preloadRootModules(loaderstate, ctx, rootPkgs)
 			if changedBuildList {
 				// The build list has changed, so the set of root packages may have also
 				// changed. Start over to pick up the changes. (Preloading roots is much
@@ -1154,7 +1154,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 
 		inRoots := map[*loadPkg]bool{}
 		for _, path := range rootPkgs {
-			root := ld.pkg(ctx, path, pkgIsRoot)
+			root := ld.pkg(loaderstate, ctx, path, pkgIsRoot)
 			if !inRoots[root] {
 				ld.roots = append(ld.roots, root)
 				inRoots[root] = true
@@ -1170,7 +1170,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 
 		ld.buildStacks()
 
-		changed, err := ld.updateRequirements(ctx)
+		changed, err := ld.updateRequirements(loaderstate, ctx)
 		if err != nil {
 			ld.error(err)
 			break
@@ -1184,12 +1184,12 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 			continue
 		}
 
-		if !ld.ResolveMissingImports || (!HasModRoot() && !allowMissingModuleImports) {
+		if !ld.ResolveMissingImports || (!HasModRoot(loaderstate) && !allowMissingModuleImports) {
 			// We've loaded as much as we can without resolving missing imports.
 			break
 		}
 
-		modAddedBy, err := ld.resolveMissingImports(ctx)
+		modAddedBy, err := ld.resolveMissingImports(loaderstate, ctx)
 		if err != nil {
 			ld.error(err)
 			break
@@ -1216,7 +1216,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 		// iteration so we don't need to also update it here. (That would waste time
 		// computing a "direct" map that we'll have to recompute later anyway.)
 		direct := ld.requirements.direct
-		rs, err := updateRoots(ctx, direct, ld.requirements, noPkgs, toAdd, ld.AssumeRootsImported)
+		rs, err := updateRoots(loaderstate, ctx, direct, ld.requirements, noPkgs, toAdd, ld.AssumeRootsImported)
 		if err != nil {
 			// If an error was found in a newly added module, report the package
 			// import stack instead of the module requirement stack. Packages
@@ -1244,7 +1244,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 	// Tidy the build list, if applicable, before we report errors.
 	// (The process of tidying may remove errors from irrelevant dependencies.)
 	if ld.Tidy {
-		rs, err := tidyRoots(ctx, ld.requirements, ld.pkgs)
+		rs, err := tidyRoots(loaderstate, ctx, ld.requirements, ld.pkgs)
 		if err != nil {
 			ld.error(err)
 		} else {
@@ -1252,8 +1252,8 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 				// Attempt to switch to the requested Go version. We have been using its
 				// pruning and semantics all along, but there may have been — and may
 				// still be — requirements on higher versions in the graph.
-				tidy := overrideRoots(ctx, rs, []module.Version{{Path: "go", Version: ld.TidyGoVersion}})
-				mg, err := tidy.Graph(ctx)
+				tidy := overrideRoots(loaderstate, ctx, rs, []module.Version{{Path: "go", Version: ld.TidyGoVersion}})
+				mg, err := tidy.Graph(loaderstate, ctx)
 				if err != nil {
 					ld.error(err)
 				}
@@ -1285,7 +1285,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 					if m.Path == "go" && ld.TidyGoVersion != "" {
 						continue
 					}
-					if v, ok := ld.requirements.rootSelected(m.Path); !ok || v != m.Version {
+					if v, ok := ld.requirements.rootSelected(loaderstate, m.Path); !ok || v != m.Version {
 						ld.error(fmt.Errorf("internal error: a requirement on %v is needed but was not added during package loading (selected %s)", m, v))
 					}
 				}
@@ -1334,7 +1334,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 		ld.error(fmt.Errorf("%s: %w", pkg.stackText(), pkg.err))
 	}
 
-	ld.checkMultiplePaths()
+	ld.checkMultiplePaths(loaderstate)
 	return ld
 }
 
@@ -1357,7 +1357,7 @@ func loadFromRoots(ctx context.Context, params loaderParams) *loader {
 // The "changed" return value reports whether the update changed the selected
 // version of any module that either provided a loaded package or may now
 // provide a package that was previously unresolved.
-func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err error) {
+func (ld *loader) updateRequirements(loaderstate *State, ctx context.Context) (changed bool, err error) {
 	rs := ld.requirements
 
 	// direct contains the set of modules believed to provide packages directly
@@ -1390,16 +1390,16 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 				}
 			}
 		}
-		if pkg.mod.Version != "" || !LoaderState.MainModules.Contains(pkg.mod.Path) {
+		if pkg.mod.Version != "" || !loaderstate.MainModules.Contains(pkg.mod.Path) {
 			continue
 		}
 
 		for _, dep := range pkg.imports {
-			if !dep.fromExternalModule() {
+			if !dep.fromExternalModule(loaderstate) {
 				continue
 			}
 
-			if inWorkspaceMode() {
+			if inWorkspaceMode(loaderstate) {
 				// In workspace mode / workspace pruning mode, the roots are the main modules
 				// rather than the main module's direct dependencies. The check below on the selected
 				// roots does not apply.
@@ -1412,7 +1412,7 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 					// of the vendor directory anyway.
 					continue
 				}
-				if mg, err := rs.Graph(ctx); err != nil {
+				if mg, err := rs.Graph(loaderstate, ctx); err != nil {
 					return false, err
 				} else if _, ok := mg.RequiredBy(dep.mod); !ok {
 					// dep.mod is not an explicit dependency, but needs to be.
@@ -1424,7 +1424,7 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 					}
 				}
 			} else if pkg.err == nil && cfg.BuildMod != "mod" {
-				if v, ok := rs.rootSelected(dep.mod.Path); !ok || v != dep.mod.Version {
+				if v, ok := rs.rootSelected(loaderstate, dep.mod.Path); !ok || v != dep.mod.Version {
 					// dep.mod is not an explicit dependency, but needs to be.
 					// Because we are not in "mod" mode, we will not be able to update it.
 					// Instead, mark the importing package with an error.
@@ -1490,21 +1490,21 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 		// roots can only increase and the set of roots can only expand. The set
 		// of extant root paths is finite and the set of versions of each path is
 		// finite, so the iteration *must* reach a stable fixed-point.
-		tidy, err := tidyRoots(ctx, rs, ld.pkgs)
+		tidy, err := tidyRoots(loaderstate, ctx, rs, ld.pkgs)
 		if err != nil {
 			return false, err
 		}
 		addRoots = tidy.rootModules
 	}
 
-	rs, err = updateRoots(ctx, direct, rs, ld.pkgs, addRoots, ld.AssumeRootsImported)
+	rs, err = updateRoots(loaderstate, ctx, direct, rs, ld.pkgs, addRoots, ld.AssumeRootsImported)
 	if err != nil {
 		// We don't actually know what even the root requirements are supposed to be,
 		// so we can't proceed with loading. Return the error to the caller
 		return false, err
 	}
 
-	if rs.GoVersion() != ld.requirements.GoVersion() {
+	if rs.GoVersion(loaderstate) != ld.requirements.GoVersion(loaderstate) {
 		// A change in the selected Go version may or may not affect the set of
 		// loaded packages, but in some cases it can change the meaning of the "all"
 		// pattern, the level of pruning in the module graph, and even the set of
@@ -1515,12 +1515,12 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 		// The roots of the module graph have changed in some way (not just the
 		// "direct" markings). Check whether the changes affected any of the loaded
 		// packages.
-		mg, err := rs.Graph(ctx)
+		mg, err := rs.Graph(loaderstate, ctx)
 		if err != nil {
 			return false, err
 		}
 		for _, pkg := range ld.pkgs {
-			if pkg.fromExternalModule() && mg.Selected(pkg.mod.Path) != pkg.mod.Version {
+			if pkg.fromExternalModule(loaderstate) && mg.Selected(pkg.mod.Path) != pkg.mod.Version {
 				changed = true
 				break
 			}
@@ -1540,7 +1540,7 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 				//
 				// In some sense, we can think of this as ‘upgraded the module providing
 				// pkg.path from "none" to a version higher than "none"’.
-				if _, _, _, _, err = importFromModules(ctx, pkg.path, rs, nil, ld.skipImportModFiles); err == nil {
+				if _, _, _, _, err = importFromModules(loaderstate, ctx, pkg.path, rs, nil, ld.skipImportModFiles); err == nil {
 					changed = true
 					break
 				}
@@ -1558,7 +1558,7 @@ func (ld *loader) updateRequirements(ctx context.Context) (changed bool, err err
 // The newly-resolved packages are added to the addedModuleFor map, and
 // resolveMissingImports returns a map from each new module version to
 // the first missing package that module would resolve.
-func (ld *loader) resolveMissingImports(ctx context.Context) (modAddedBy map[module.Version]*loadPkg, err error) {
+func (ld *loader) resolveMissingImports(loaderstate *State, ctx context.Context) (modAddedBy map[module.Version]*loadPkg, err error) {
 	type pkgMod struct {
 		pkg *loadPkg
 		mod *module.Version
@@ -1582,11 +1582,11 @@ func (ld *loader) resolveMissingImports(ctx context.Context) (modAddedBy map[mod
 		var mod module.Version
 		ld.work.Add(func() {
 			var err error
-			mod, err = queryImport(ctx, pkg.path, ld.requirements)
+			mod, err = queryImport(loaderstate, ctx, pkg.path, ld.requirements)
 			if err != nil {
 				if ime, ok := errors.AsType[*ImportMissingError](err); ok {
 					for curstack := pkg.stack; curstack != nil; curstack = curstack.stack {
-						if LoaderState.MainModules.Contains(curstack.mod.Path) {
+						if loaderstate.MainModules.Contains(curstack.mod.Path) {
 							ime.ImportingMainModule = curstack.mod
 							break
 						}
@@ -1658,7 +1658,7 @@ func (ld *loader) resolveMissingImports(ctx context.Context) (modAddedBy map[mod
 // ld.work queue, and its test (if requested) will also be populated once
 // imports have been resolved. When ld.work goes idle, all transitive imports of
 // the requested package (and its test, if requested) will have been loaded.
-func (ld *loader) pkg(ctx context.Context, path string, flags loadPkgFlags) *loadPkg {
+func (ld *loader) pkg(loaderstate *State, ctx context.Context, path string, flags loadPkgFlags) *loadPkg {
 	if flags.has(pkgImportsLoaded) {
 		panic("internal error: (*loader).pkg called with pkgImportsLoaded flag set")
 	}
@@ -1667,20 +1667,20 @@ func (ld *loader) pkg(ctx context.Context, path string, flags loadPkgFlags) *loa
 		pkg := &loadPkg{
 			path: path,
 		}
-		ld.applyPkgFlags(ctx, pkg, flags)
+		ld.applyPkgFlags(loaderstate, ctx, pkg, flags)
 
-		ld.work.Add(func() { ld.load(ctx, pkg) })
+		ld.work.Add(func() { ld.load(loaderstate, ctx, pkg) })
 		return pkg
 	})
 
-	ld.applyPkgFlags(ctx, pkg, flags)
+	ld.applyPkgFlags(loaderstate, ctx, pkg, flags)
 	return pkg
 }
 
 // applyPkgFlags updates pkg.flags to set the given flags and propagate the
 // (transitive) effects of those flags, possibly loading or enqueueing further
 // packages as a result.
-func (ld *loader) applyPkgFlags(ctx context.Context, pkg *loadPkg, flags loadPkgFlags) {
+func (ld *loader) applyPkgFlags(loaderstate *State, ctx context.Context, pkg *loadPkg, flags loadPkgFlags) {
 	if flags == 0 {
 		return
 	}
@@ -1708,7 +1708,7 @@ func (ld *loader) applyPkgFlags(ctx context.Context, pkg *loadPkg, flags loadPkg
 		// so it's ok if we call it more than is strictly necessary.
 		wantTest := false
 		switch {
-		case ld.allPatternIsRoot && LoaderState.MainModules.Contains(pkg.mod.Path):
+		case ld.allPatternIsRoot && loaderstate.MainModules.Contains(pkg.mod.Path):
 			// We are loading the "all" pattern, which includes packages imported by
 			// tests in the main module. This package is in the main module, so we
 			// need to identify the imports of its test even if LoadTests is not set.
@@ -1729,13 +1729,13 @@ func (ld *loader) applyPkgFlags(ctx context.Context, pkg *loadPkg, flags loadPkg
 
 		if wantTest {
 			var testFlags loadPkgFlags
-			if LoaderState.MainModules.Contains(pkg.mod.Path) || (ld.allClosesOverTests && new.has(pkgInAll)) {
+			if loaderstate.MainModules.Contains(pkg.mod.Path) || (ld.allClosesOverTests && new.has(pkgInAll)) {
 				// Tests of packages in the main module are in "all", in the sense that
 				// they cause the packages they import to also be in "all". So are tests
 				// of packages in "all" if "all" closes over test dependencies.
 				testFlags |= pkgInAll
 			}
-			ld.pkgTest(ctx, pkg, testFlags)
+			ld.pkgTest(loaderstate, ctx, pkg, testFlags)
 		}
 	}
 
@@ -1743,13 +1743,13 @@ func (ld *loader) applyPkgFlags(ctx context.Context, pkg *loadPkg, flags loadPkg
 		// We have just marked pkg with pkgInAll, or we have just loaded its
 		// imports, or both. Now is the time to propagate pkgInAll to the imports.
 		for _, dep := range pkg.imports {
-			ld.applyPkgFlags(ctx, dep, pkgInAll)
+			ld.applyPkgFlags(loaderstate, ctx, dep, pkgInAll)
 		}
 	}
 
 	if new.has(pkgFromRoot) && !old.has(pkgFromRoot|pkgImportsLoaded) {
 		for _, dep := range pkg.imports {
-			ld.applyPkgFlags(ctx, dep, pkgFromRoot)
+			ld.applyPkgFlags(loaderstate, ctx, dep, pkgFromRoot)
 		}
 	}
 }
@@ -1757,7 +1757,7 @@ func (ld *loader) applyPkgFlags(ctx context.Context, pkg *loadPkg, flags loadPkg
 // preloadRootModules loads the module requirements needed to identify the
 // selected version of each module providing a package in rootPkgs,
 // adding new root modules to the module graph if needed.
-func (ld *loader) preloadRootModules(ctx context.Context, rootPkgs []string) (changedBuildList bool) {
+func (ld *loader) preloadRootModules(loaderstate *State, ctx context.Context, rootPkgs []string) (changedBuildList bool) {
 	needc := make(chan map[module.Version]bool, 1)
 	needc <- map[module.Version]bool{}
 	for _, path := range rootPkgs {
@@ -1768,12 +1768,12 @@ func (ld *loader) preloadRootModules(ctx context.Context, rootPkgs []string) (ch
 			// If the main module is tidy and the package is in "all" — or if we're
 			// lucky — we can identify all of its imports without actually loading the
 			// full module graph.
-			m, _, _, _, err := importFromModules(ctx, path, ld.requirements, nil, ld.skipImportModFiles)
+			m, _, _, _, err := importFromModules(loaderstate, ctx, path, ld.requirements, nil, ld.skipImportModFiles)
 			if err != nil {
 				if _, ok := errors.AsType[*ImportMissingError](err); ok && ld.ResolveMissingImports {
 					// This package isn't provided by any selected module.
 					// If we can find it, it will be a new root dependency.
-					m, err = queryImport(ctx, path, ld.requirements)
+					m, err = queryImport(loaderstate, ctx, path, ld.requirements)
 				}
 				if err != nil {
 					// We couldn't identify the root module containing this package.
@@ -1786,7 +1786,7 @@ func (ld *loader) preloadRootModules(ctx context.Context, rootPkgs []string) (ch
 				return
 			}
 
-			v, ok := ld.requirements.rootSelected(m.Path)
+			v, ok := ld.requirements.rootSelected(loaderstate, m.Path)
 			if !ok || v != m.Version {
 				// We found the requested package in m, but m is not a root, so
 				// loadModGraph will not load its requirements. We need to promote the
@@ -1814,7 +1814,7 @@ func (ld *loader) preloadRootModules(ctx context.Context, rootPkgs []string) (ch
 	}
 	gover.ModSort(toAdd)
 
-	rs, err := updateRoots(ctx, ld.requirements.direct, ld.requirements, nil, toAdd, ld.AssumeRootsImported)
+	rs, err := updateRoots(loaderstate, ctx, ld.requirements.direct, ld.requirements, nil, toAdd, ld.AssumeRootsImported)
 	if err != nil {
 		// We are missing some root dependency, and for some reason we can't load
 		// enough of the module dependency graph to add the missing root. Package
@@ -1836,11 +1836,11 @@ func (ld *loader) preloadRootModules(ctx context.Context, rootPkgs []string) (ch
 }
 
 // load loads an individual package.
-func (ld *loader) load(ctx context.Context, pkg *loadPkg) {
+func (ld *loader) load(loaderstate *State, ctx context.Context, pkg *loadPkg) {
 	var mg *ModuleGraph
 	if ld.requirements.pruning == unpruned {
 		var err error
-		mg, err = ld.requirements.Graph(ctx)
+		mg, err = ld.requirements.Graph(loaderstate, ctx)
 		if err != nil {
 			// We already checked the error from Graph in loadFromRoots and/or
 			// updateRequirements, so we ignored the error on purpose and we should
@@ -1855,17 +1855,17 @@ func (ld *loader) load(ctx context.Context, pkg *loadPkg) {
 	}
 
 	var modroot string
-	pkg.mod, modroot, pkg.dir, pkg.altMods, pkg.err = importFromModules(ctx, pkg.path, ld.requirements, mg, ld.skipImportModFiles)
-	if LoaderState.MainModules.Tools()[pkg.path] {
+	pkg.mod, modroot, pkg.dir, pkg.altMods, pkg.err = importFromModules(loaderstate, ctx, pkg.path, ld.requirements, mg, ld.skipImportModFiles)
+	if loaderstate.MainModules.Tools()[pkg.path] {
 		// Tools declared by main modules are always in "all".
 		// We apply the package flags before returning so that missing
 		// tool dependencies report an error https://go.dev/issue/70582
-		ld.applyPkgFlags(ctx, pkg, pkgInAll)
+		ld.applyPkgFlags(loaderstate, ctx, pkg, pkgInAll)
 	}
 	if pkg.dir == "" {
 		return
 	}
-	if LoaderState.MainModules.Contains(pkg.mod.Path) {
+	if loaderstate.MainModules.Contains(pkg.mod.Path) {
 		// Go ahead and mark pkg as in "all". This provides the invariant that a
 		// package that is *only* imported by other packages in "all" is always
 		// marked as such before loading its imports.
@@ -1875,7 +1875,7 @@ func (ld *loader) load(ctx context.Context, pkg *loadPkg) {
 		// about (by reducing churn on the flag bits of dependencies), and costs
 		// essentially nothing (these atomic flag ops are essentially free compared
 		// to scanning source code for imports).
-		ld.applyPkgFlags(ctx, pkg, pkgInAll)
+		ld.applyPkgFlags(loaderstate, ctx, pkg, pkgInAll)
 	}
 	if ld.AllowPackage != nil {
 		if err := ld.AllowPackage(ctx, pkg.path, pkg.mod); err != nil {
@@ -1907,13 +1907,13 @@ func (ld *loader) load(ctx context.Context, pkg *loadPkg) {
 		if pkg.inStd {
 			// Imports from packages in "std" and "cmd" should resolve using
 			// GOROOT/src/vendor even when "std" is not the main module.
-			path = ld.stdVendor(pkg.path, path)
+			path = ld.stdVendor(loaderstate, pkg.path, path)
 		}
-		pkg.imports = append(pkg.imports, ld.pkg(ctx, path, importFlags))
+		pkg.imports = append(pkg.imports, ld.pkg(loaderstate, ctx, path, importFlags))
 	}
 	pkg.testImports = testImports
 
-	ld.applyPkgFlags(ctx, pkg, pkgImportsLoaded)
+	ld.applyPkgFlags(loaderstate, ctx, pkg, pkgImportsLoaded)
 }
 
 // pkgTest locates the test of pkg, creating it if needed, and updates its state
@@ -1921,7 +1921,7 @@ func (ld *loader) load(ctx context.Context, pkg *loadPkg) {
 //
 // pkgTest requires that the imports of pkg have already been loaded (flagged
 // with pkgImportsLoaded).
-func (ld *loader) pkgTest(ctx context.Context, pkg *loadPkg, testFlags loadPkgFlags) *loadPkg {
+func (ld *loader) pkgTest(loaderstate *State, ctx context.Context, pkg *loadPkg, testFlags loadPkgFlags) *loadPkg {
 	if pkg.isTest() {
 		panic("pkgTest called on a test package")
 	}
@@ -1936,7 +1936,7 @@ func (ld *loader) pkgTest(ctx context.Context, pkg *loadPkg, testFlags loadPkgFl
 			err:    pkg.err,
 			inStd:  pkg.inStd,
 		}
-		ld.applyPkgFlags(ctx, pkg.test, testFlags)
+		ld.applyPkgFlags(loaderstate, ctx, pkg.test, testFlags)
 		createdTest = true
 	})
 
@@ -1949,14 +1949,14 @@ func (ld *loader) pkgTest(ctx context.Context, pkg *loadPkg, testFlags loadPkgFl
 		}
 		for _, path := range pkg.testImports {
 			if pkg.inStd {
-				path = ld.stdVendor(test.path, path)
+				path = ld.stdVendor(loaderstate, test.path, path)
 			}
-			test.imports = append(test.imports, ld.pkg(ctx, path, importFlags))
+			test.imports = append(test.imports, ld.pkg(loaderstate, ctx, path, importFlags))
 		}
 		pkg.testImports = nil
-		ld.applyPkgFlags(ctx, test, pkgImportsLoaded)
+		ld.applyPkgFlags(loaderstate, ctx, test, pkgImportsLoaded)
 	} else {
-		ld.applyPkgFlags(ctx, test, testFlags)
+		ld.applyPkgFlags(loaderstate, ctx, test, testFlags)
 	}
 
 	return test
@@ -1964,7 +1964,7 @@ func (ld *loader) pkgTest(ctx context.Context, pkg *loadPkg, testFlags loadPkgFl
 
 // stdVendor returns the canonical import path for the package with the given
 // path when imported from the standard-library package at parentPath.
-func (ld *loader) stdVendor(parentPath, path string) string {
+func (ld *loader) stdVendor(loaderstate *State, parentPath, path string) string {
 	if p, _, ok := fips140.ResolveImport(path); ok {
 		return p
 	}
@@ -1973,14 +1973,14 @@ func (ld *loader) stdVendor(parentPath, path string) string {
 	}
 
 	if str.HasPathPrefix(parentPath, "cmd") {
-		if !ld.VendorModulesInGOROOTSrc || !LoaderState.MainModules.Contains("cmd") {
+		if !ld.VendorModulesInGOROOTSrc || !loaderstate.MainModules.Contains("cmd") {
 			vendorPath := pathpkg.Join("cmd", "vendor", path)
 
 			if _, err := os.Stat(filepath.Join(cfg.GOROOTsrc, filepath.FromSlash(vendorPath))); err == nil {
 				return vendorPath
 			}
 		}
-	} else if !ld.VendorModulesInGOROOTSrc || !LoaderState.MainModules.Contains("std") || str.HasPathPrefix(parentPath, "vendor") {
+	} else if !ld.VendorModulesInGOROOTSrc || !loaderstate.MainModules.Contains("std") || str.HasPathPrefix(parentPath, "vendor") {
 		// If we are outside of the 'std' module, resolve imports from within 'std'
 		// to the vendor directory.
 		//
@@ -2026,7 +2026,7 @@ func (ld *loader) computePatternAll() (all []string) {
 // or as a replacement for another module, but not both at the same time.
 //
 // (See https://golang.org/issue/26607 and https://golang.org/issue/34650.)
-func (ld *loader) checkMultiplePaths() {
+func (ld *loader) checkMultiplePaths(loaderstate *State) {
 	mods := ld.requirements.rootModules
 	if cached := ld.requirements.graph.Load(); cached != nil {
 		if mg := cached.mg; mg != nil {
@@ -2036,7 +2036,7 @@ func (ld *loader) checkMultiplePaths() {
 
 	firstPath := map[module.Version]string{}
 	for _, mod := range mods {
-		src := resolveReplacement(mod)
+		src := resolveReplacement(loaderstate, mod)
 		if prev, ok := firstPath[src]; !ok {
 			firstPath[src] = mod.Path
 		} else if prev != mod.Path {
@@ -2047,8 +2047,8 @@ func (ld *loader) checkMultiplePaths() {
 
 // checkTidyCompatibility emits an error if any package would be loaded from a
 // different module under rs than under ld.requirements.
-func (ld *loader) checkTidyCompatibility(ctx context.Context, rs *Requirements, compatVersion string) {
-	goVersion := rs.GoVersion()
+func (ld *loader) checkTidyCompatibility(loaderstate *State, ctx context.Context, rs *Requirements, compatVersion string) {
+	goVersion := rs.GoVersion(loaderstate)
 	suggestUpgrade := false
 	suggestEFlag := false
 	suggestFixes := func() {
@@ -2065,7 +2065,7 @@ func (ld *loader) checkTidyCompatibility(ctx context.Context, rs *Requirements,
 		fmt.Fprintln(os.Stderr)
 
 		goFlag := ""
-		if goVersion != LoaderState.MainModules.GoVersion() {
+		if goVersion != loaderstate.MainModules.GoVersion(loaderstate) {
 			goFlag = " -go=" + goVersion
 		}
 
@@ -2094,7 +2094,7 @@ func (ld *loader) checkTidyCompatibility(ctx context.Context, rs *Requirements,
 		fmt.Fprintf(os.Stderr, "For information about 'go mod tidy' compatibility, see:\n\thttps://go.dev/ref/mod#graph-pruning\n")
 	}
 
-	mg, err := rs.Graph(ctx)
+	mg, err := rs.Graph(loaderstate, ctx)
 	if err != nil {
 		ld.error(fmt.Errorf("error loading go %s module graph: %w", compatVersion, err))
 		ld.switchIfErrors(ctx)
@@ -2132,7 +2132,7 @@ func (ld *loader) checkTidyCompatibility(ctx context.Context, rs *Requirements,
 
 		pkg := pkg
 		ld.work.Add(func() {
-			mod, _, _, _, err := importFromModules(ctx, pkg.path, rs, mg, ld.skipImportModFiles)
+			mod, _, _, _, err := importFromModules(loaderstate, ctx, pkg.path, rs, mg, ld.skipImportModFiles)
 			if mod != pkg.mod {
 				mismatches := <-mismatchMu
 				mismatches[pkg] = mismatch{mod: mod, err: err}
diff --git a/src/cmd/go/internal/modload/modfile.go b/src/cmd/go/internal/modload/modfile.go
index 3fdbdc7010b993..20feb8fcacc784 100644
--- a/src/cmd/go/internal/modload/modfile.go
+++ b/src/cmd/go/internal/modload/modfile.go
@@ -142,7 +142,7 @@ func CheckAllowed(ctx context.Context, m module.Version) error {
 	if err := CheckExclusions(ctx, m); err != nil {
 		return err
 	}
-	if err := CheckRetractions(ctx, m); err != nil {
+	if err := CheckRetractions(LoaderState, ctx, m); err != nil {
 		return err
 	}
 	return nil
@@ -172,7 +172,7 @@ func (e *excludedError) Is(err error) bool { return err == ErrDisallowed }
 
 // CheckRetractions returns an error if module m has been retracted by
 // its author.
-func CheckRetractions(ctx context.Context, m module.Version) (err error) {
+func CheckRetractions(loaderstate *State, ctx context.Context, m module.Version) (err error) {
 	defer func() {
 		if err == nil {
 			return
@@ -193,7 +193,7 @@ func CheckRetractions(ctx context.Context, m module.Version) (err error) {
 		// Cannot be retracted.
 		return nil
 	}
-	if repl := Replacement(module.Version{Path: m.Path}); repl.Path != "" {
+	if repl := Replacement(loaderstate, module.Version{Path: m.Path}); repl.Path != "" {
 		// All versions of the module were replaced.
 		// Don't load retractions, since we'd just load the replacement.
 		return nil
@@ -210,11 +210,11 @@ func CheckRetractions(ctx context.Context, m module.Version) (err error) {
 	// We load the raw file here: the go.mod file may have a different module
 	// path that we expect if the module or its repository was renamed.
 	// We still want to apply retractions to other aliases of the module.
-	rm, err := queryLatestVersionIgnoringRetractions(ctx, m.Path)
+	rm, err := queryLatestVersionIgnoringRetractions(loaderstate, ctx, m.Path)
 	if err != nil {
 		return err
 	}
-	summary, err := rawGoModSummary(rm)
+	summary, err := rawGoModSummary(loaderstate, rm)
 	if err != nil && !errors.Is(err, gover.ErrTooNew) {
 		return err
 	}
@@ -300,7 +300,7 @@ func ShortMessage(message, emptyDefault string) string {
 //
 // CheckDeprecation returns an error if the message can't be loaded.
 // CheckDeprecation returns "", nil if there is no deprecation message.
-func CheckDeprecation(ctx context.Context, m module.Version) (deprecation string, err error) {
+func CheckDeprecation(loaderstate *State, ctx context.Context, m module.Version) (deprecation string, err error) {
 	defer func() {
 		if err != nil {
 			err = fmt.Errorf("loading deprecation for %s: %w", m.Path, err)
@@ -312,17 +312,17 @@ func CheckDeprecation(ctx context.Context, m module.Version) (deprecation string
 		// Don't look up deprecation.
 		return "", nil
 	}
-	if repl := Replacement(module.Version{Path: m.Path}); repl.Path != "" {
+	if repl := Replacement(loaderstate, module.Version{Path: m.Path}); repl.Path != "" {
 		// All versions of the module were replaced.
 		// We'll look up deprecation separately for the replacement.
 		return "", nil
 	}
 
-	latest, err := queryLatestVersionIgnoringRetractions(ctx, m.Path)
+	latest, err := queryLatestVersionIgnoringRetractions(loaderstate, ctx, m.Path)
 	if err != nil {
 		return "", err
 	}
-	summary, err := rawGoModSummary(latest)
+	summary, err := rawGoModSummary(loaderstate, latest)
 	if err != nil && !errors.Is(err, gover.ErrTooNew) {
 		return "", err
 	}
@@ -342,28 +342,28 @@ func replacement(mod module.Version, replace map[module.Version]module.Version)
 // Replacement returns the replacement for mod, if any. If the path in the
 // module.Version is relative it's relative to the single main module outside
 // workspace mode, or the workspace's directory in workspace mode.
-func Replacement(mod module.Version) module.Version {
-	r, foundModRoot, _ := replacementFrom(mod)
-	return canonicalizeReplacePath(r, foundModRoot)
+func Replacement(loaderstate *State, mod module.Version) module.Version {
+	r, foundModRoot, _ := replacementFrom(loaderstate, mod)
+	return canonicalizeReplacePath(loaderstate, r, foundModRoot)
 }
 
 // replacementFrom returns the replacement for mod, if any, the modroot of the replacement if it appeared in a go.mod,
 // and the source of the replacement. The replacement is relative to the go.work or go.mod file it appears in.
-func replacementFrom(mod module.Version) (r module.Version, modroot string, fromFile string) {
+func replacementFrom(loaderstate *State, mod module.Version) (r module.Version, modroot string, fromFile string) {
 	foundFrom, found, foundModRoot := "", module.Version{}, ""
-	if LoaderState.MainModules == nil {
+	if loaderstate.MainModules == nil {
 		return module.Version{}, "", ""
-	} else if LoaderState.MainModules.Contains(mod.Path) && mod.Version == "" {
+	} else if loaderstate.MainModules.Contains(mod.Path) && mod.Version == "" {
 		// Don't replace the workspace version of the main module.
 		return module.Version{}, "", ""
 	}
-	if _, r, ok := replacement(mod, LoaderState.MainModules.WorkFileReplaceMap()); ok {
-		return r, "", LoaderState.workFilePath
+	if _, r, ok := replacement(mod, loaderstate.MainModules.WorkFileReplaceMap()); ok {
+		return r, "", loaderstate.workFilePath
 	}
-	for _, v := range LoaderState.MainModules.Versions() {
-		if index := LoaderState.MainModules.Index(v); index != nil {
+	for _, v := range loaderstate.MainModules.Versions() {
+		if index := loaderstate.MainModules.Index(v); index != nil {
 			if from, r, ok := replacement(mod, index.replace); ok {
-				modRoot := LoaderState.MainModules.ModRoot(v)
+				modRoot := loaderstate.MainModules.ModRoot(v)
 				if foundModRoot != "" && foundFrom != from && found != r {
 					base.Errorf("conflicting replacements found for %v in workspace modules defined by %v and %v",
 						mod, modFilePath(foundModRoot), modFilePath(modRoot))
@@ -376,21 +376,21 @@ func replacementFrom(mod module.Version) (r module.Version, modroot string, from
 	return found, foundModRoot, modFilePath(foundModRoot)
 }
 
-func replaceRelativeTo() string {
-	if workFilePath := WorkFilePath(); workFilePath != "" {
+func replaceRelativeTo(loaderstate *State) string {
+	if workFilePath := WorkFilePath(loaderstate); workFilePath != "" {
 		return filepath.Dir(workFilePath)
 	}
-	return LoaderState.MainModules.ModRoot(LoaderState.MainModules.mustGetSingleMainModule())
+	return loaderstate.MainModules.ModRoot(loaderstate.MainModules.mustGetSingleMainModule(loaderstate))
 }
 
 // canonicalizeReplacePath ensures that relative, on-disk, replaced module paths
 // are relative to the workspace directory (in workspace mode) or to the module's
 // directory (in module mode, as they already are).
-func canonicalizeReplacePath(r module.Version, modRoot string) module.Version {
+func canonicalizeReplacePath(loaderstate *State, r module.Version, modRoot string) module.Version {
 	if filepath.IsAbs(r.Path) || r.Version != "" || modRoot == "" {
 		return r
 	}
-	workFilePath := WorkFilePath()
+	workFilePath := WorkFilePath(loaderstate)
 	if workFilePath == "" {
 		return r
 	}
@@ -407,8 +407,8 @@ func canonicalizeReplacePath(r module.Version, modRoot string) module.Version {
 // for m: either m itself, or the replacement for m (iff m is replaced).
 // It also returns the modroot of the module providing the replacement if
 // one was found.
-func resolveReplacement(m module.Version) module.Version {
-	if r := Replacement(m); r.Path != "" {
+func resolveReplacement(loaderstate *State, m module.Version) module.Version {
+	if r := Replacement(loaderstate, m); r.Path != "" {
 		return r
 	}
 	return m
@@ -573,12 +573,12 @@ type retraction struct {
 // module versions.
 //
 // The caller must not modify the returned summary.
-func goModSummary(m module.Version) (*modFileSummary, error) {
-	if m.Version == "" && !inWorkspaceMode() && LoaderState.MainModules.Contains(m.Path) {
+func goModSummary(loaderstate *State, m module.Version) (*modFileSummary, error) {
+	if m.Version == "" && !inWorkspaceMode(loaderstate) && loaderstate.MainModules.Contains(m.Path) {
 		panic("internal error: goModSummary called on a main module")
 	}
 	if gover.IsToolchain(m.Path) {
-		return rawGoModSummary(m)
+		return rawGoModSummary(loaderstate, m)
 	}
 
 	if cfg.BuildMod == "vendor" {
@@ -586,7 +586,7 @@ func goModSummary(m module.Version) (*modFileSummary, error) {
 			module: module.Version{Path: m.Path},
 		}
 
-		readVendorList(VendorDir())
+		readVendorList(VendorDir(loaderstate))
 		if vendorVersion[m.Path] != m.Version {
 			// This module is not vendored, so packages cannot be loaded from it and
 			// it cannot be relevant to the build.
@@ -601,15 +601,15 @@ func goModSummary(m module.Version) (*modFileSummary, error) {
 		return summary, nil
 	}
 
-	actual := resolveReplacement(m)
-	if mustHaveSums() && actual.Version != "" {
+	actual := resolveReplacement(loaderstate, m)
+	if mustHaveSums(loaderstate) && actual.Version != "" {
 		key := module.Version{Path: actual.Path, Version: actual.Version + "/go.mod"}
 		if !modfetch.HaveSum(key) {
 			suggestion := fmt.Sprintf(" for go.mod file; to add it:\n\tgo mod download %s", m.Path)
 			return nil, module.VersionError(actual, &sumMissingError{suggestion: suggestion})
 		}
 	}
-	summary, err := rawGoModSummary(actual)
+	summary, err := rawGoModSummary(loaderstate, actual)
 	if err != nil {
 		return nil, err
 	}
@@ -641,8 +641,8 @@ func goModSummary(m module.Version) (*modFileSummary, error) {
 		}
 	}
 
-	for _, mainModule := range LoaderState.MainModules.Versions() {
-		if index := LoaderState.MainModules.Index(mainModule); index != nil && len(index.exclude) > 0 {
+	for _, mainModule := range loaderstate.MainModules.Versions() {
+		if index := loaderstate.MainModules.Index(mainModule); index != nil && len(index.exclude) > 0 {
 			// Drop any requirements on excluded versions.
 			// Don't modify the cached summary though, since we might need the raw
 			// summary separately.
@@ -676,7 +676,7 @@ func goModSummary(m module.Version) (*modFileSummary, error) {
 // rawGoModSummary cannot be used on the main module outside of workspace mode.
 // The modFileSummary can still be used for retractions and deprecations
 // even if a TooNewError is returned.
-func rawGoModSummary(m module.Version) (*modFileSummary, error) {
+func rawGoModSummary(loaderstate *State, m module.Version) (*modFileSummary, error) {
 	if gover.IsToolchain(m.Path) {
 		if m.Path == "go" && gover.Compare(m.Version, gover.GoStrictVersion) >= 0 {
 			// Declare that go 1.21.3 requires toolchain 1.21.3,
@@ -686,7 +686,7 @@ func rawGoModSummary(m module.Version) (*modFileSummary, error) {
 		}
 		return &modFileSummary{module: m}, nil
 	}
-	if m.Version == "" && !inWorkspaceMode() && LoaderState.MainModules.Contains(m.Path) {
+	if m.Version == "" && !inWorkspaceMode(loaderstate) && loaderstate.MainModules.Contains(m.Path) {
 		// Calling rawGoModSummary implies that we are treating m as a module whose
 		// requirements aren't the roots of the module graph and can't be modified.
 		//
@@ -694,22 +694,22 @@ func rawGoModSummary(m module.Version) (*modFileSummary, error) {
 		// are the roots of the module graph and we expect them to be kept consistent.
 		panic("internal error: rawGoModSummary called on a main module")
 	}
-	if m.Version == "" && inWorkspaceMode() && m.Path == "command-line-arguments" {
+	if m.Version == "" && inWorkspaceMode(loaderstate) && m.Path == "command-line-arguments" {
 		// "go work sync" calls LoadModGraph to make sure the module graph is valid.
 		// If there are no modules in the workspace, we synthesize an empty
 		// command-line-arguments module, which rawGoModData cannot read a go.mod for.
 		return &modFileSummary{module: m}, nil
-	} else if m.Version == "" && inWorkspaceMode() && LoaderState.MainModules.Contains(m.Path) {
+	} else if m.Version == "" && inWorkspaceMode(loaderstate) && loaderstate.MainModules.Contains(m.Path) {
 		// When go get uses EnterWorkspace to check that the workspace loads properly,
 		// it will update the contents of the workspace module's modfile in memory. To use the updated
 		// contents of the modfile when doing the load, don't read from disk and instead
 		// recompute a summary using the updated contents of the modfile.
-		if mf := LoaderState.MainModules.ModFile(m); mf != nil {
-			return summaryFromModFile(m, LoaderState.MainModules.modFiles[m])
+		if mf := loaderstate.MainModules.ModFile(m); mf != nil {
+			return summaryFromModFile(m, loaderstate.MainModules.modFiles[m])
 		}
 	}
 	return rawGoModSummaryCache.Do(m, func() (*modFileSummary, error) {
-		name, data, err := rawGoModData(m)
+		name, data, err := rawGoModData(loaderstate, m)
 		if err != nil {
 			return nil, err
 		}
@@ -781,15 +781,15 @@ var rawGoModSummaryCache par.ErrCache[module.Version, *modFileSummary]
 //
 // Unlike rawGoModSummary, rawGoModData does not cache its results in memory.
 // Use rawGoModSummary instead unless you specifically need these bytes.
-func rawGoModData(m module.Version) (name string, data []byte, err error) {
+func rawGoModData(loaderstate *State, m module.Version) (name string, data []byte, err error) {
 	if m.Version == "" {
 		dir := m.Path
 		if !filepath.IsAbs(dir) {
-			if inWorkspaceMode() && LoaderState.MainModules.Contains(m.Path) {
-				dir = LoaderState.MainModules.ModRoot(m)
+			if inWorkspaceMode(loaderstate) && loaderstate.MainModules.Contains(m.Path) {
+				dir = loaderstate.MainModules.ModRoot(m)
 			} else {
 				// m is a replacement module with only a file path.
-				dir = filepath.Join(replaceRelativeTo(), dir)
+				dir = filepath.Join(replaceRelativeTo(loaderstate), dir)
 			}
 		}
 		name = filepath.Join(dir, "go.mod")
@@ -825,12 +825,12 @@ func rawGoModData(m module.Version) (name string, data []byte, err error) {
 //
 // If the queried latest version is replaced,
 // queryLatestVersionIgnoringRetractions returns the replacement.
-func queryLatestVersionIgnoringRetractions(ctx context.Context, path string) (latest module.Version, err error) {
+func queryLatestVersionIgnoringRetractions(loaderstate *State, ctx context.Context, path string) (latest module.Version, err error) {
 	return latestVersionIgnoringRetractionsCache.Do(path, func() (module.Version, error) {
 		ctx, span := trace.StartSpan(ctx, "queryLatestVersionIgnoringRetractions "+path)
 		defer span.Done()
 
-		if repl := Replacement(module.Version{Path: path}); repl.Path != "" {
+		if repl := Replacement(loaderstate, module.Version{Path: path}); repl.Path != "" {
 			// All versions of the module were replaced.
 			// No need to query.
 			return repl, nil
@@ -840,12 +840,12 @@ func queryLatestVersionIgnoringRetractions(ctx context.Context, path string) (la
 		// Ignore exclusions from the main module's go.mod.
 		const ignoreSelected = ""
 		var allowAll AllowedFunc
-		rev, err := Query(ctx, path, "latest", ignoreSelected, allowAll)
+		rev, err := Query(loaderstate, ctx, path, "latest", ignoreSelected, allowAll)
 		if err != nil {
 			return module.Version{}, err
 		}
 		latest := module.Version{Path: path, Version: rev.Version}
-		if repl := resolveReplacement(latest); repl.Path != "" {
+		if repl := resolveReplacement(loaderstate, latest); repl.Path != "" {
 			latest = repl
 		}
 		return latest, nil
diff --git a/src/cmd/go/internal/modload/mvs.go b/src/cmd/go/internal/modload/mvs.go
index 97e6fe44dd7545..32afc866fbcc14 100644
--- a/src/cmd/go/internal/modload/mvs.go
+++ b/src/cmd/go/internal/modload/mvs.go
@@ -53,7 +53,7 @@ func (r *mvsReqs) Required(mod module.Version) ([]module.Version, error) {
 		return nil, nil
 	}
 
-	summary, err := goModSummary(mod)
+	summary, err := goModSummary(LoaderState, mod)
 	if err != nil {
 		return nil, err
 	}
@@ -79,11 +79,11 @@ func (*mvsReqs) Upgrade(m module.Version) (module.Version, error) {
 	return m, nil
 }
 
-func versions(ctx context.Context, path string, allowed AllowedFunc) (versions []string, origin *codehost.Origin, err error) {
+func versions(loaderstate *State, ctx context.Context, path string, allowed AllowedFunc) (versions []string, origin *codehost.Origin, err error) {
 	// Note: modfetch.Lookup and repo.Versions are cached,
 	// so there's no need for us to add extra caching here.
 	err = modfetch.TryProxies(func(proxy string) error {
-		repo, err := lookupRepo(ctx, proxy, path)
+		repo, err := lookupRepo(loaderstate, ctx, proxy, path)
 		if err != nil {
 			return err
 		}
@@ -111,12 +111,12 @@ func versions(ctx context.Context, path string, allowed AllowedFunc) (versions [
 //
 // Since the version of a main module is not found in the version list,
 // it has no previous version.
-func previousVersion(ctx context.Context, m module.Version) (module.Version, error) {
-	if m.Version == "" && LoaderState.MainModules.Contains(m.Path) {
+func previousVersion(loaderstate *State, ctx context.Context, m module.Version) (module.Version, error) {
+	if m.Version == "" && loaderstate.MainModules.Contains(m.Path) {
 		return module.Version{Path: m.Path, Version: "none"}, nil
 	}
 
-	list, _, err := versions(ctx, m.Path, CheckAllowed)
+	list, _, err := versions(loaderstate, ctx, m.Path, CheckAllowed)
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
 			return module.Version{Path: m.Path, Version: "none"}, nil
@@ -132,5 +132,5 @@ func previousVersion(ctx context.Context, m module.Version) (module.Version, err
 
 func (*mvsReqs) Previous(m module.Version) (module.Version, error) {
 	// TODO(golang.org/issue/38714): thread tracing context through MVS.
-	return previousVersion(context.TODO(), m)
+	return previousVersion(LoaderState, context.TODO(), m)
 }
diff --git a/src/cmd/go/internal/modload/query.go b/src/cmd/go/internal/modload/query.go
index b37a244fbbacdd..17a0aef21ab2e9 100644
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@@ -80,19 +80,19 @@ import (
 //
 // Query often returns a non-nil *RevInfo with a non-nil error,
 // to provide an info.Origin that can allow the error to be cached.
-func Query(ctx context.Context, path, query, current string, allowed AllowedFunc) (*modfetch.RevInfo, error) {
+func Query(loaderstate *State, ctx context.Context, path, query, current string, allowed AllowedFunc) (*modfetch.RevInfo, error) {
 	ctx, span := trace.StartSpan(ctx, "modload.Query "+path)
 	defer span.Done()
 
-	return queryReuse(ctx, path, query, current, allowed, nil)
+	return queryReuse(loaderstate, ctx, path, query, current, allowed, nil)
 }
 
 // queryReuse is like Query but also takes a map of module info that can be reused
 // if the validation criteria in Origin are met.
-func queryReuse(ctx context.Context, path, query, current string, allowed AllowedFunc, reuse map[module.Version]*modinfo.ModulePublic) (*modfetch.RevInfo, error) {
+func queryReuse(loaderstate *State, ctx context.Context, path, query, current string, allowed AllowedFunc, reuse map[module.Version]*modinfo.ModulePublic) (*modfetch.RevInfo, error) {
 	var info *modfetch.RevInfo
 	err := modfetch.TryProxies(func(proxy string) (err error) {
-		info, err = queryProxy(ctx, proxy, path, query, current, allowed, reuse)
+		info, err = queryProxy(loaderstate, ctx, proxy, path, query, current, allowed, reuse)
 		return err
 	})
 	return info, err
@@ -100,9 +100,9 @@ func queryReuse(ctx context.Context, path, query, current string, allowed Allowe
 
 // checkReuse checks whether a revision of a given module
 // for a given module may be reused, according to the information in origin.
-func checkReuse(ctx context.Context, m module.Version, old *codehost.Origin) error {
+func checkReuse(loaderstate *State, ctx context.Context, m module.Version, old *codehost.Origin) error {
 	return modfetch.TryProxies(func(proxy string) error {
-		repo, err := lookupRepo(ctx, proxy, m.Path)
+		repo, err := lookupRepo(loaderstate, ctx, proxy, m.Path)
 		if err != nil {
 			return err
 		}
@@ -197,7 +197,7 @@ func (queryDisabledError) Error() string {
 	return fmt.Sprintf("cannot query module due to -mod=%s\n\t(%s)", cfg.BuildMod, cfg.BuildModReason)
 }
 
-func queryProxy(ctx context.Context, proxy, path, query, current string, allowed AllowedFunc, reuse map[module.Version]*modinfo.ModulePublic) (*modfetch.RevInfo, error) {
+func queryProxy(loaderstate *State, ctx context.Context, proxy, path, query, current string, allowed AllowedFunc, reuse map[module.Version]*modinfo.ModulePublic) (*modfetch.RevInfo, error) {
 	ctx, span := trace.StartSpan(ctx, "modload.queryProxy "+path+" "+query)
 	defer span.Done()
 
@@ -211,7 +211,7 @@ func queryProxy(ctx context.Context, proxy, path, query, current string, allowed
 		allowed = func(context.Context, module.Version) error { return nil }
 	}
 
-	if LoaderState.MainModules.Contains(path) && (query == "upgrade" || query == "patch") {
+	if loaderstate.MainModules.Contains(path) && (query == "upgrade" || query == "patch") {
 		m := module.Version{Path: path}
 		if err := allowed(ctx, m); err != nil {
 			return nil, fmt.Errorf("internal error: main module version is not allowed: %w", err)
@@ -223,7 +223,7 @@ func queryProxy(ctx context.Context, proxy, path, query, current string, allowed
 		return nil, fmt.Errorf("can't query specific version (%q) of standard-library module %q", query, path)
 	}
 
-	repo, err := lookupRepo(ctx, proxy, path)
+	repo, err := lookupRepo(loaderstate, ctx, proxy, path)
 	if err != nil {
 		return nil, err
 	}
@@ -296,7 +296,7 @@ func queryProxy(ctx context.Context, proxy, path, query, current string, allowed
 		return &clone
 	}
 
-	releases, prereleases, err := qm.filterVersions(ctx, versions.List)
+	releases, prereleases, err := qm.filterVersions(loaderstate, ctx, versions.List)
 	if err != nil {
 		return revWithOrigin(nil), err
 	}
@@ -569,7 +569,7 @@ func (qm *queryMatcher) allowsVersion(ctx context.Context, v string) bool {
 //
 // If the allowed predicate returns an error not equivalent to ErrDisallowed,
 // filterVersions returns that error.
-func (qm *queryMatcher) filterVersions(ctx context.Context, versions []string) (releases, prereleases []string, err error) {
+func (qm *queryMatcher) filterVersions(loaderstate *State, ctx context.Context, versions []string) (releases, prereleases []string, err error) {
 	needIncompatible := qm.preferIncompatible
 
 	var lastCompatible string
@@ -602,7 +602,7 @@ func (qm *queryMatcher) filterVersions(ctx context.Context, versions []string) (
 				// ignore any version with a higher (+incompatible) major version. (See
 				// https://golang.org/issue/34165.) Note that we even prefer a
 				// compatible pre-release over an incompatible release.
-				ok, err := versionHasGoMod(ctx, module.Version{Path: qm.path, Version: lastCompatible})
+				ok, err := versionHasGoMod(loaderstate, ctx, module.Version{Path: qm.path, Version: lastCompatible})
 				if err != nil {
 					return nil, nil, err
 				}
@@ -639,11 +639,11 @@ type QueryResult struct {
 
 // QueryPackages is like QueryPattern, but requires that the pattern match at
 // least one package and omits the non-package result (if any).
-func QueryPackages(ctx context.Context, pattern, query string, current func(string) string, allowed AllowedFunc) ([]QueryResult, error) {
-	pkgMods, modOnly, err := QueryPattern(ctx, pattern, query, current, allowed)
+func QueryPackages(loaderstate *State, ctx context.Context, pattern, query string, current func(string) string, allowed AllowedFunc) ([]QueryResult, error) {
+	pkgMods, modOnly, err := QueryPattern(loaderstate, ctx, pattern, query, current, allowed)
 
 	if len(pkgMods) == 0 && err == nil {
-		replacement := Replacement(modOnly.Mod)
+		replacement := Replacement(loaderstate, modOnly.Mod)
 		return nil, &PackageNotInModuleError{
 			Mod:         modOnly.Mod,
 			Replacement: replacement,
@@ -670,7 +670,7 @@ func QueryPackages(ctx context.Context, pattern, query string, current func(stri
 //
 // QueryPattern always returns at least one QueryResult (which may be only
 // modOnly) or a non-nil error.
-func QueryPattern(ctx context.Context, pattern, query string, current func(string) string, allowed AllowedFunc) (pkgMods []QueryResult, modOnly *QueryResult, err error) {
+func QueryPattern(loaderstate *State, ctx context.Context, pattern, query string, current func(string) string, allowed AllowedFunc) (pkgMods []QueryResult, modOnly *QueryResult, err error) {
 	ctx, span := trace.StartSpan(ctx, "modload.QueryPattern "+pattern+" "+query)
 	defer span.Done()
 
@@ -693,15 +693,15 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 		}
 		match = func(mod module.Version, roots []string, isLocal bool) *search.Match {
 			m := search.NewMatch(pattern)
-			matchPackages(ctx, m, imports.AnyTags(), omitStd, []module.Version{mod})
+			matchPackages(loaderstate, ctx, m, imports.AnyTags(), omitStd, []module.Version{mod})
 			return m
 		}
 	} else {
 		match = func(mod module.Version, roots []string, isLocal bool) *search.Match {
 			m := search.NewMatch(pattern)
 			prefix := mod.Path
-			if LoaderState.MainModules.Contains(mod.Path) {
-				prefix = LoaderState.MainModules.PathPrefix(module.Version{Path: mod.Path})
+			if loaderstate.MainModules.Contains(mod.Path) {
+				prefix = loaderstate.MainModules.PathPrefix(module.Version{Path: mod.Path})
 			}
 			for _, root := range roots {
 				if _, ok, err := dirInModule(pattern, prefix, root, isLocal); err != nil {
@@ -715,8 +715,8 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 	}
 
 	var mainModuleMatches []module.Version
-	for _, mainModule := range LoaderState.MainModules.Versions() {
-		m := match(mainModule, LoaderState.modRoots, true)
+	for _, mainModule := range loaderstate.MainModules.Versions() {
+		m := match(mainModule, loaderstate.modRoots, true)
 		if len(m.Pkgs) > 0 {
 			if query != "upgrade" && query != "patch" {
 				return nil, nil, &QueryMatchesPackagesInMainModuleError{
@@ -756,7 +756,7 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 
 	var (
 		results          []QueryResult
-		candidateModules = modulePrefixesExcludingTarget(base)
+		candidateModules = modulePrefixesExcludingTarget(loaderstate, base)
 	)
 	if len(candidateModules) == 0 {
 		if modOnly != nil {
@@ -783,7 +783,7 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 
 			pathCurrent := current(path)
 			r.Mod.Path = path
-			r.Rev, err = queryProxy(ctx, proxy, path, query, pathCurrent, allowed, nil)
+			r.Rev, err = queryProxy(loaderstate, ctx, proxy, path, query, pathCurrent, allowed, nil)
 			if err != nil {
 				return r, err
 			}
@@ -791,7 +791,7 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 			if gover.IsToolchain(r.Mod.Path) {
 				return r, nil
 			}
-			root, isLocal, err := fetch(ctx, r.Mod)
+			root, isLocal, err := fetch(loaderstate, ctx, r.Mod)
 			if err != nil {
 				return r, err
 			}
@@ -801,7 +801,7 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 				if err := firstError(m); err != nil {
 					return r, err
 				}
-				replacement := Replacement(r.Mod)
+				replacement := Replacement(loaderstate, r.Mod)
 				return r, &PackageNotInModuleError{
 					Mod:         r.Mod,
 					Replacement: replacement,
@@ -812,7 +812,7 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 			return r, nil
 		}
 
-		allResults, err := queryPrefixModules(ctx, candidateModules, queryModule)
+		allResults, err := queryPrefixModules(loaderstate, ctx, candidateModules, queryModule)
 		results = allResults[:0]
 		for _, r := range allResults {
 			if len(r.Packages) == 0 {
@@ -838,11 +838,11 @@ func QueryPattern(ctx context.Context, pattern, query string, current func(strin
 // itself, sorted by descending length. Prefixes that are not valid module paths
 // but are valid package paths (like "m" or "example.com/.gen") are included,
 // since they might be replaced.
-func modulePrefixesExcludingTarget(path string) []string {
+func modulePrefixesExcludingTarget(loaderstate *State, path string) []string {
 	prefixes := make([]string, 0, strings.Count(path, "/")+1)
 
 	mainModulePrefixes := make(map[string]bool)
-	for _, m := range LoaderState.MainModules.Versions() {
+	for _, m := range loaderstate.MainModules.Versions() {
 		mainModulePrefixes[m.Path] = true
 	}
 
@@ -863,7 +863,7 @@ func modulePrefixesExcludingTarget(path string) []string {
 	return prefixes
 }
 
-func queryPrefixModules(ctx context.Context, candidateModules []string, queryModule func(ctx context.Context, path string) (QueryResult, error)) (found []QueryResult, err error) {
+func queryPrefixModules(loaderstate *State, ctx context.Context, candidateModules []string, queryModule func(ctx context.Context, path string) (QueryResult, error)) (found []QueryResult, err error) {
 	ctx, span := trace.StartSpan(ctx, "modload.queryPrefixModules")
 	defer span.Done()
 
@@ -905,7 +905,7 @@ func queryPrefixModules(ctx context.Context, candidateModules []string, queryMod
 		case *PackageNotInModuleError:
 			// Given the option, prefer to attribute “package not in module”
 			// to modules other than the main one.
-			if noPackage == nil || LoaderState.MainModules.Contains(noPackage.Mod.Path) {
+			if noPackage == nil || loaderstate.MainModules.Contains(noPackage.Mod.Path) {
 				noPackage = rErr
 			}
 		case *NoMatchingVersionError:
@@ -1096,8 +1096,8 @@ func (e *PackageNotInModuleError) ImportPath() string {
 // go.mod with different content. Second, if we don't fetch the .zip, then
 // we don't need to verify it in go.sum. This makes 'go list -m -u' faster
 // and simpler.
-func versionHasGoMod(_ context.Context, m module.Version) (bool, error) {
-	_, data, err := rawGoModData(m)
+func versionHasGoMod(loaderstate *State, _ context.Context, m module.Version) (bool, error) {
+	_, data, err := rawGoModData(loaderstate, m)
 	if err != nil {
 		return false, err
 	}
@@ -1117,7 +1117,7 @@ type versionRepo interface {
 
 var _ versionRepo = modfetch.Repo(nil)
 
-func lookupRepo(ctx context.Context, proxy, path string) (repo versionRepo, err error) {
+func lookupRepo(loaderstate *State, ctx context.Context, proxy, path string) (repo versionRepo, err error) {
 	if path != "go" && path != "toolchain" {
 		err = module.CheckPath(path)
 	}
@@ -1127,9 +1127,9 @@ func lookupRepo(ctx context.Context, proxy, path string) (repo versionRepo, err
 		repo = emptyRepo{path: path, err: err}
 	}
 
-	if LoaderState.MainModules == nil {
+	if loaderstate.MainModules == nil {
 		return repo, err
-	} else if _, ok := LoaderState.MainModules.HighestReplaced()[path]; ok {
+	} else if _, ok := loaderstate.MainModules.HighestReplaced()[path]; ok {
 		return &replacementRepo{repo: repo}, nil
 	}
 
@@ -1239,7 +1239,7 @@ func (rr *replacementRepo) Stat(ctx context.Context, rev string) (*modfetch.RevI
 		}
 	}
 
-	if r := Replacement(module.Version{Path: path, Version: v}); r.Path == "" {
+	if r := Replacement(LoaderState, module.Version{Path: path, Version: v}); r.Path == "" {
 		return info, err
 	}
 	return rr.replacementStat(v)
diff --git a/src/cmd/go/internal/modload/query_test.go b/src/cmd/go/internal/modload/query_test.go
index 93f8f0d00d1c8d..b4487eebb0d9e9 100644
--- a/src/cmd/go/internal/modload/query_test.go
+++ b/src/cmd/go/internal/modload/query_test.go
@@ -182,7 +182,7 @@ func TestQuery(t *testing.T) {
 		t.Run(strings.ReplaceAll(tt.path, "/", "_")+"/"+tt.query+"/"+tt.current+"/"+allow, func(t *testing.T) {
 			t.Parallel()
 
-			info, err := Query(ctx, tt.path, tt.query, tt.current, allowed)
+			info, err := Query(LoaderState, ctx, tt.path, tt.query, tt.current, allowed)
 			if tt.err != "" {
 				if err == nil {
 					t.Errorf("Query(_, %q, %q, %q, %v) = %v, want error %q", tt.path, tt.query, tt.current, allow, info.Version, tt.err)
diff --git a/src/cmd/go/internal/modload/search.go b/src/cmd/go/internal/modload/search.go
index 205db3e8f7c8db..9951e68ee8e6c9 100644
--- a/src/cmd/go/internal/modload/search.go
+++ b/src/cmd/go/internal/modload/search.go
@@ -41,7 +41,7 @@ const (
 // matchPackages is like m.MatchPackages, but uses a local variable (rather than
 // a global) for tags, can include or exclude packages in the standard library,
 // and is restricted to the given list of modules.
-func matchPackages(ctx context.Context, m *search.Match, tags map[string]bool, filter stdFilter, modules []module.Version) {
+func matchPackages(loaderstate *State, ctx context.Context, m *search.Match, tags map[string]bool, filter stdFilter, modules []module.Version) {
 	ctx, span := trace.StartSpan(ctx, "modload.matchPackages")
 	defer span.Done()
 
@@ -74,7 +74,7 @@ func matchPackages(ctx context.Context, m *search.Match, tags map[string]bool, f
 	)
 
 	q := par.NewQueue(runtime.GOMAXPROCS(0))
-	ignorePatternsMap := parseIgnorePatterns(ctx, treeCanMatch, modules)
+	ignorePatternsMap := parseIgnorePatterns(loaderstate, ctx, treeCanMatch, modules)
 	walkPkgs := func(root, importPathRoot string, prune pruning) {
 		_, span := trace.StartSpan(ctx, "walkPkgs "+root)
 		defer span.Done()
@@ -171,13 +171,13 @@ func matchPackages(ctx context.Context, m *search.Match, tags map[string]bool, f
 	}
 
 	if cfg.BuildMod == "vendor" {
-		for _, mod := range LoaderState.MainModules.Versions() {
-			if modRoot := LoaderState.MainModules.ModRoot(mod); modRoot != "" {
-				walkPkgs(modRoot, LoaderState.MainModules.PathPrefix(mod), pruneGoMod|pruneVendor)
+		for _, mod := range loaderstate.MainModules.Versions() {
+			if modRoot := loaderstate.MainModules.ModRoot(mod); modRoot != "" {
+				walkPkgs(modRoot, loaderstate.MainModules.PathPrefix(mod), pruneGoMod|pruneVendor)
 			}
 		}
-		if HasModRoot() {
-			walkPkgs(VendorDir(), "", pruneVendor)
+		if HasModRoot(loaderstate) {
+			walkPkgs(VendorDir(loaderstate), "", pruneVendor)
 		}
 		return
 	}
@@ -191,16 +191,16 @@ func matchPackages(ctx context.Context, m *search.Match, tags map[string]bool, f
 			root, modPrefix string
 			isLocal         bool
 		)
-		if LoaderState.MainModules.Contains(mod.Path) {
-			if LoaderState.MainModules.ModRoot(mod) == "" {
+		if loaderstate.MainModules.Contains(mod.Path) {
+			if loaderstate.MainModules.ModRoot(mod) == "" {
 				continue // If there is no main module, we can't search in it.
 			}
-			root = LoaderState.MainModules.ModRoot(mod)
-			modPrefix = LoaderState.MainModules.PathPrefix(mod)
+			root = loaderstate.MainModules.ModRoot(mod)
+			modPrefix = loaderstate.MainModules.PathPrefix(mod)
 			isLocal = true
 		} else {
 			var err error
-			root, isLocal, err = fetch(ctx, mod)
+			root, isLocal, err = fetch(loaderstate, ctx, mod)
 			if err != nil {
 				m.AddError(err)
 				continue
@@ -286,17 +286,17 @@ func walkFromIndex(index *modindex.Module, importPathRoot string, isMatch, treeC
 func MatchInModule(ctx context.Context, pattern string, m module.Version, tags map[string]bool) *search.Match {
 	match := search.NewMatch(pattern)
 	if m == (module.Version{}) {
-		matchPackages(ctx, match, tags, includeStd, nil)
+		matchPackages(LoaderState, ctx, match, tags, includeStd, nil)
 	}
 
-	LoadModFile(ctx) // Sets Target, needed by fetch and matchPackages.
+	LoadModFile(LoaderState, ctx) // Sets Target, needed by fetch and matchPackages.
 
 	if !match.IsLiteral() {
-		matchPackages(ctx, match, tags, omitStd, []module.Version{m})
+		matchPackages(LoaderState, ctx, match, tags, omitStd, []module.Version{m})
 		return match
 	}
 
-	root, isLocal, err := fetch(ctx, m)
+	root, isLocal, err := fetch(LoaderState, ctx, m)
 	if err != nil {
 		match.Errs = []error{err}
 		return match
@@ -322,7 +322,7 @@ func MatchInModule(ctx context.Context, pattern string, m module.Version, tags m
 // parseIgnorePatterns collects all ignore patterns associated with the
 // provided list of modules.
 // It returns a map of module root -> *search.IgnorePatterns.
-func parseIgnorePatterns(ctx context.Context, treeCanMatch func(string) bool, modules []module.Version) map[string]*search.IgnorePatterns {
+func parseIgnorePatterns(loaderstate *State, ctx context.Context, treeCanMatch func(string) bool, modules []module.Version) map[string]*search.IgnorePatterns {
 	ignorePatternsMap := make(map[string]*search.IgnorePatterns)
 	for _, mod := range modules {
 		if gover.IsToolchain(mod.Path) || !treeCanMatch(mod.Path) {
@@ -330,12 +330,12 @@ func parseIgnorePatterns(ctx context.Context, treeCanMatch func(string) bool, mo
 		}
 		var modRoot string
 		var ignorePatterns []string
-		if LoaderState.MainModules.Contains(mod.Path) {
-			modRoot = LoaderState.MainModules.ModRoot(mod)
+		if loaderstate.MainModules.Contains(mod.Path) {
+			modRoot = loaderstate.MainModules.ModRoot(mod)
 			if modRoot == "" {
 				continue
 			}
-			modIndex := LoaderState.MainModules.Index(mod)
+			modIndex := loaderstate.MainModules.Index(mod)
 			if modIndex == nil {
 				continue
 			}
@@ -344,11 +344,11 @@ func parseIgnorePatterns(ctx context.Context, treeCanMatch func(string) bool, mo
 			// Skip getting ignore patterns for vendored modules because they
 			// do not have go.mod files.
 			var err error
-			modRoot, _, err = fetch(ctx, mod)
+			modRoot, _, err = fetch(loaderstate, ctx, mod)
 			if err != nil {
 				continue
 			}
-			summary, err := goModSummary(mod)
+			summary, err := goModSummary(loaderstate, mod)
 			if err != nil {
 				continue
 			}
diff --git a/src/cmd/go/internal/modload/vendor.go b/src/cmd/go/internal/modload/vendor.go
index d3f055acf64f50..bf0c4e403717a6 100644
--- a/src/cmd/go/internal/modload/vendor.go
+++ b/src/cmd/go/internal/modload/vendor.go
@@ -140,10 +140,10 @@ func readVendorList(vendorDir string) {
 // checkVendorConsistency verifies that the vendor/modules.txt file matches (if
 // go 1.14) or at least does not contradict (go 1.13 or earlier) the
 // requirements and replacements listed in the main module's go.mod file.
-func checkVendorConsistency(indexes []*modFileIndex, modFiles []*modfile.File, modRoots []string) {
+func checkVendorConsistency(loaderstate *State, indexes []*modFileIndex, modFiles []*modfile.File, modRoots []string) {
 	// readVendorList only needs the main module to get the directory
 	// the vendor directory is in.
-	readVendorList(VendorDir())
+	readVendorList(VendorDir(loaderstate))
 
 	if len(modFiles) < 1 {
 		// We should never get here if there are zero modfiles. Either
@@ -154,7 +154,7 @@ func checkVendorConsistency(indexes []*modFileIndex, modFiles []*modfile.File, m
 	}
 
 	pre114 := false
-	if !inWorkspaceMode() { // workspace mode was added after Go 1.14
+	if !inWorkspaceMode(loaderstate) { // workspace mode was added after Go 1.14
 		if len(indexes) != 1 {
 			panic(fmt.Errorf("not in workspace mode but number of indexes is %v, not 1", len(indexes)))
 		}
@@ -215,8 +215,8 @@ func checkVendorConsistency(indexes []*modFileIndex, modFiles []*modfile.File, m
 				continue // Don't print the same error more than once
 			}
 			seenrep[r.Old] = true
-			rNew, modRoot, replacementSource := replacementFrom(r.Old)
-			rNewCanonical := canonicalizeReplacePath(rNew, modRoot)
+			rNew, modRoot, replacementSource := replacementFrom(loaderstate, r.Old)
+			rNewCanonical := canonicalizeReplacePath(loaderstate, rNew, modRoot)
 			vr := vendorMeta[r.Old].Replacement
 			if vr == (module.Version{}) {
 				if rNewCanonical == (module.Version{}) {
@@ -236,8 +236,8 @@ func checkVendorConsistency(indexes []*modFileIndex, modFiles []*modfile.File, m
 	for _, modFile := range modFiles {
 		checkReplace(modFile.Replace)
 	}
-	if LoaderState.MainModules.workFile != nil {
-		checkReplace(LoaderState.MainModules.workFile.Replace)
+	if loaderstate.MainModules.workFile != nil {
+		checkReplace(loaderstate.MainModules.workFile.Replace)
 	}
 
 	for _, mod := range vendorList {
@@ -252,7 +252,7 @@ func checkVendorConsistency(indexes []*modFileIndex, modFiles []*modfile.File, m
 			}
 			if !foundRequire {
 				article := ""
-				if inWorkspaceMode() {
+				if inWorkspaceMode(loaderstate) {
 					article = "a "
 				}
 				vendErrorf(mod, "is marked as explicit in vendor/modules.txt, but not explicitly required in %vgo.mod", article)
@@ -262,9 +262,9 @@ func checkVendorConsistency(indexes []*modFileIndex, modFiles []*modfile.File, m
 	}
 
 	for _, mod := range vendorReplaced {
-		r := Replacement(mod)
+		r := Replacement(loaderstate, mod)
 		replacementSource := "go.mod"
-		if inWorkspaceMode() {
+		if inWorkspaceMode(loaderstate) {
 			replacementSource = "the workspace"
 		}
 		if r == (module.Version{}) {
@@ -276,9 +276,9 @@ func checkVendorConsistency(indexes []*modFileIndex, modFiles []*modfile.File, m
 
 	if vendErrors.Len() > 0 {
 		subcmd := "mod"
-		if inWorkspaceMode() {
+		if inWorkspaceMode(loaderstate) {
 			subcmd = "work"
 		}
-		base.Fatalf("go: inconsistent vendoring in %s:%s\n\n\tTo ignore the vendor directory, use -mod=readonly or -mod=mod.\n\tTo sync the vendor directory, run:\n\t\tgo %s vendor", filepath.Dir(VendorDir()), vendErrors, subcmd)
+		base.Fatalf("go: inconsistent vendoring in %s:%s\n\n\tTo ignore the vendor directory, use -mod=readonly or -mod=mod.\n\tTo sync the vendor directory, run:\n\t\tgo %s vendor", filepath.Dir(VendorDir(loaderstate)), vendErrors, subcmd)
 	}
 }
diff --git a/src/cmd/go/internal/run/run.go b/src/cmd/go/internal/run/run.go
index d922dcdd66a551..b6d76514b032d8 100644
--- a/src/cmd/go/internal/run/run.go
+++ b/src/cmd/go/internal/run/run.go
@@ -78,13 +78,13 @@ func runRun(ctx context.Context, cmd *base.Command, args []string) {
 		// for -race and -msan.
 		modload.LoaderState.ForceUseModules = true
 		modload.LoaderState.RootMode = modload.NoRoot
-		modload.AllowMissingModuleImports()
-		modload.Init()
+		modload.AllowMissingModuleImports(modload.LoaderState)
+		modload.Init(modload.LoaderState)
 	} else {
-		modload.InitWorkfile()
+		modload.InitWorkfile(modload.LoaderState)
 	}
 
-	work.BuildInit()
+	work.BuildInit(modload.LoaderState)
 	b := work.NewBuilder("")
 	defer func() {
 		if err := b.Close(); err != nil {
@@ -107,18 +107,18 @@ func runRun(ctx context.Context, cmd *base.Command, args []string) {
 				base.Fatalf("go: cannot run *_test.go files (%s)", file)
 			}
 		}
-		p = load.GoFilesPackage(ctx, pkgOpts, files)
+		p = load.GoFilesPackage(modload.LoaderState, ctx, pkgOpts, files)
 	} else if len(args) > 0 && !strings.HasPrefix(args[0], "-") {
 		arg := args[0]
 		var pkgs []*load.Package
 		if strings.Contains(arg, "@") && !build.IsLocalImport(arg) && !filepath.IsAbs(arg) {
 			var err error
-			pkgs, err = load.PackagesAndErrorsOutsideModule(ctx, pkgOpts, args[:1])
+			pkgs, err = load.PackagesAndErrorsOutsideModule(modload.LoaderState, ctx, pkgOpts, args[:1])
 			if err != nil {
 				base.Fatal(err)
 			}
 		} else {
-			pkgs = load.PackagesAndErrors(ctx, pkgOpts, args[:1])
+			pkgs = load.PackagesAndErrors(modload.LoaderState, ctx, pkgOpts, args[:1])
 		}
 
 		if len(pkgs) == 0 {
@@ -140,7 +140,7 @@ func runRun(ctx context.Context, cmd *base.Command, args []string) {
 	load.CheckPackageErrors([]*load.Package{p})
 
 	if cfg.BuildCover {
-		load.PrepareForCoverageBuild([]*load.Package{p})
+		load.PrepareForCoverageBuild(modload.LoaderState, []*load.Package{p})
 	}
 
 	p.Internal.OmitDebug = true
@@ -166,7 +166,7 @@ func runRun(ctx context.Context, cmd *base.Command, args []string) {
 		p.Internal.ExeName = p.DefaultExecName()
 	}
 
-	a1 := b.LinkAction(work.ModeBuild, work.ModeBuild, p)
+	a1 := b.LinkAction(modload.LoaderState, work.ModeBuild, work.ModeBuild, p)
 	a1.CacheExecutable = true
 	a := &work.Action{Mode: "go run", Actor: work.ActorFunc(buildRunProgram), Args: cmdArgs, Deps: []*work.Action{a1}}
 	b.Do(ctx, a)
diff --git a/src/cmd/go/internal/telemetrystats/telemetrystats.go b/src/cmd/go/internal/telemetrystats/telemetrystats.go
index d5b642240f16b7..9586324551dfc9 100644
--- a/src/cmd/go/internal/telemetrystats/telemetrystats.go
+++ b/src/cmd/go/internal/telemetrystats/telemetrystats.go
@@ -24,7 +24,7 @@ func Increment() {
 func incrementConfig() {
 	if !modload.WillBeEnabled() {
 		counter.Inc("go/mode:gopath")
-	} else if workfile := modload.FindGoWork(base.Cwd()); workfile != "" {
+	} else if workfile := modload.FindGoWork(modload.LoaderState, base.Cwd()); workfile != "" {
 		counter.Inc("go/mode:workspace")
 	} else {
 		counter.Inc("go/mode:module")
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index e225929add20c2..5e5d79a39f001f 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -683,7 +683,7 @@ var defaultVetFlags = []string{
 
 func runTest(ctx context.Context, cmd *base.Command, args []string) {
 	pkgArgs, testArgs = testFlags(args)
-	modload.InitWorkfile() // The test command does custom flag processing; initialize workspaces after that.
+	modload.InitWorkfile(modload.LoaderState) // The test command does custom flag processing; initialize workspaces after that.
 
 	if cfg.DebugTrace != "" {
 		var close func() error
@@ -704,13 +704,13 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 
 	work.FindExecCmd() // initialize cached result
 
-	work.BuildInit()
+	work.BuildInit(modload.LoaderState)
 	work.VetFlags = testVet.flags
 	work.VetExplicit = testVet.explicit
 	work.VetTool = base.Tool("vet")
 
 	pkgOpts := load.PackageOpts{ModResolveTests: true}
-	pkgs = load.PackagesAndErrors(ctx, pkgOpts, pkgArgs)
+	pkgs = load.PackagesAndErrors(modload.LoaderState, ctx, pkgOpts, pkgArgs)
 	// We *don't* call load.CheckPackageErrors here because we want to report
 	// loading errors as per-package test setup errors later.
 	if len(pkgs) == 0 {
@@ -741,7 +741,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 			if !mainMods.Contains(m.Path) {
 				base.Fatalf("cannot use -fuzz flag on package outside the main module")
 			}
-		} else if pkgs[0].Standard && modload.Enabled() {
+		} else if pkgs[0].Standard && modload.Enabled(modload.LoaderState) {
 			// Because packages in 'std' and 'cmd' are part of the standard library,
 			// they are only treated as part of a module in 'go mod' subcommands and
 			// 'go get'. However, we still don't want to accidentally corrupt their
@@ -867,13 +867,13 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 	if cfg.BuildCoverPkg != nil {
 		match := make([]func(*load.Package) bool, len(cfg.BuildCoverPkg))
 		for i := range cfg.BuildCoverPkg {
-			match[i] = load.MatchPackage(cfg.BuildCoverPkg[i], base.Cwd())
+			match[i] = load.MatchPackage(modload.LoaderState, cfg.BuildCoverPkg[i], base.Cwd())
 		}
 
 		// Select for coverage all dependencies matching the -coverpkg
 		// patterns.
 		plist := load.TestPackageList(ctx, pkgOpts, pkgs)
-		testCoverPkgs = load.SelectCoverPackages(plist, match, "test")
+		testCoverPkgs = load.SelectCoverPackages(modload.LoaderState, plist, match, "test")
 		if len(testCoverPkgs) > 0 {
 			// create a new singleton action that will collect up the
 			// meta-data files from all of the packages mentioned in
@@ -981,7 +981,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 			// happens we'll wind up building the Q compile action
 			// before updating its deps to include sync/atomic).
 			if cfg.BuildCoverMode == "atomic" && p.ImportPath != "sync/atomic" {
-				load.EnsureImport(p, "sync/atomic")
+				load.EnsureImport(modload.LoaderState, p, "sync/atomic")
 			}
 			// Tag the package for static meta-data generation if no
 			// test files (this works only with the new coverage
@@ -1221,7 +1221,7 @@ func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts,
 		}
 	}
 
-	a := b.LinkAction(work.ModeBuild, work.ModeBuild, pmain)
+	a := b.LinkAction(modload.LoaderState, work.ModeBuild, work.ModeBuild, pmain)
 	a.Target = testDir + testBinary + cfg.ExeSuffix
 	if cfg.Goos == "windows" {
 		// There are many reserved words on Windows that,
diff --git a/src/cmd/go/internal/tool/tool.go b/src/cmd/go/internal/tool/tool.go
index e25c06a8f046bd..e95b07d8c813aa 100644
--- a/src/cmd/go/internal/tool/tool.go
+++ b/src/cmd/go/internal/tool/tool.go
@@ -161,8 +161,8 @@ func listTools(ctx context.Context) {
 		fmt.Println(name)
 	}
 
-	modload.InitWorkfile()
-	modload.LoadModFile(ctx)
+	modload.InitWorkfile(modload.LoaderState)
+	modload.LoadModFile(modload.LoaderState, ctx)
 	modTools := slices.Sorted(maps.Keys(modload.LoaderState.MainModules.Tools()))
 	for _, tool := range modTools {
 		fmt.Println(tool)
@@ -252,8 +252,8 @@ func loadBuiltinTool(toolName string) string {
 }
 
 func loadModTool(ctx context.Context, name string) string {
-	modload.InitWorkfile()
-	modload.LoadModFile(ctx)
+	modload.InitWorkfile(modload.LoaderState)
+	modload.LoadModFile(modload.LoaderState, ctx)
 
 	matches := []string{}
 	for tool := range modload.LoaderState.MainModules.Tools() {
@@ -336,7 +336,7 @@ func buildAndRunModtool(ctx context.Context, toolName, tool string, args []strin
 }
 
 func buildAndRunTool(ctx context.Context, tool string, args []string, runTool work.ActorFunc) {
-	work.BuildInit()
+	work.BuildInit(modload.LoaderState)
 	b := work.NewBuilder("")
 	defer func() {
 		if err := b.Close(); err != nil {
@@ -345,11 +345,11 @@ func buildAndRunTool(ctx context.Context, tool string, args []string, runTool wo
 	}()
 
 	pkgOpts := load.PackageOpts{MainOnly: true}
-	p := load.PackagesAndErrors(ctx, pkgOpts, []string{tool})[0]
+	p := load.PackagesAndErrors(modload.LoaderState, ctx, pkgOpts, []string{tool})[0]
 	p.Internal.OmitDebug = true
 	p.Internal.ExeName = p.DefaultExecName()
 
-	a1 := b.LinkAction(work.ModeBuild, work.ModeBuild, p)
+	a1 := b.LinkAction(modload.LoaderState, work.ModeBuild, work.ModeBuild, p)
 	a1.CacheExecutable = true
 	a := &work.Action{Mode: "go tool", Actor: runTool, Args: args, Deps: []*work.Action{a1}}
 	b.Do(ctx, a)
diff --git a/src/cmd/go/internal/toolchain/select.go b/src/cmd/go/internal/toolchain/select.go
index 4f46b19c12167b..d54277ed1b4bea 100644
--- a/src/cmd/go/internal/toolchain/select.go
+++ b/src/cmd/go/internal/toolchain/select.go
@@ -355,7 +355,7 @@ func Exec(gotoolchain string) {
 	modload.Reset()
 	modload.LoaderState.ForceUseModules = true
 	modload.LoaderState.RootMode = modload.NoRoot
-	modload.Init()
+	modload.Init(modload.LoaderState)
 
 	// Download and unpack toolchain module into module cache.
 	// Note that multiple go commands might be doing this at the same time,
@@ -529,7 +529,7 @@ func raceSafeCopy(old, new string) error {
 // The toolchain line overrides the version line
 func modGoToolchain() (file, goVers, toolchain string) {
 	wd := base.UncachedCwd()
-	file = modload.FindGoWork(wd)
+	file = modload.FindGoWork(modload.LoaderState, wd)
 	// $GOWORK can be set to a file that does not yet exist, if we are running 'go work init'.
 	// Do not try to load the file in that case
 	if _, err := os.Stat(file); err != nil {
@@ -694,7 +694,7 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 	// Set up modules without an explicit go.mod, to download go.mod.
 	modload.LoaderState.ForceUseModules = true
 	modload.LoaderState.RootMode = modload.NoRoot
-	modload.Init()
+	modload.Init(modload.LoaderState)
 	defer modload.Reset()
 
 	// See internal/load.PackagesAndErrorsOutsideModule
@@ -705,7 +705,7 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 		allowed = nil
 	}
 	noneSelected := func(path string) (version string) { return "none" }
-	_, err := modload.QueryPackages(ctx, path, version, noneSelected, allowed)
+	_, err := modload.QueryPackages(modload.LoaderState, ctx, path, version, noneSelected, allowed)
 	if errors.Is(err, gover.ErrTooNew) {
 		// Run early switch, same one go install or go run would eventually do,
 		// if it understood all the command-line flags.
diff --git a/src/cmd/go/internal/vet/vet.go b/src/cmd/go/internal/vet/vet.go
index a2625b21188cf4..e274348bd6a38e 100644
--- a/src/cmd/go/internal/vet/vet.go
+++ b/src/cmd/go/internal/vet/vet.go
@@ -123,7 +123,7 @@ func run(ctx context.Context, cmd *base.Command, args []string) {
 
 	// The vet/fix commands do custom flag processing;
 	// initialize workspaces after that.
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 
 	if cfg.DebugTrace != "" {
 		var close func() error
@@ -142,7 +142,7 @@ func run(ctx context.Context, cmd *base.Command, args []string) {
 	ctx, span := trace.StartSpan(ctx, fmt.Sprint("Running ", cmd.Name(), " command"))
 	defer span.Done()
 
-	work.BuildInit()
+	work.BuildInit(modload.LoaderState)
 
 	// Flag theory:
 	//
@@ -217,7 +217,7 @@ func run(ctx context.Context, cmd *base.Command, args []string) {
 	work.VetFlags = toolFlags
 
 	pkgOpts := load.PackageOpts{ModResolveTests: true}
-	pkgs := load.PackagesAndErrors(ctx, pkgOpts, pkgArgs)
+	pkgs := load.PackagesAndErrors(modload.LoaderState, ctx, pkgOpts, pkgArgs)
 	load.CheckPackageErrors(pkgs)
 	if len(pkgs) == 0 {
 		base.Fatalf("no packages to %s", cmd.Name())
diff --git a/src/cmd/go/internal/work/action.go b/src/cmd/go/internal/work/action.go
index 3636f642e26401..f1f3bcea38d9d5 100644
--- a/src/cmd/go/internal/work/action.go
+++ b/src/cmd/go/internal/work/action.go
@@ -28,6 +28,7 @@ import (
 	"cmd/go/internal/cache"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/load"
+	"cmd/go/internal/modload"
 	"cmd/go/internal/str"
 	"cmd/go/internal/trace"
 	"cmd/internal/buildid"
@@ -392,7 +393,7 @@ func (b *Builder) NewObjdir() string {
 // at shlibpath. For the native toolchain this list is stored, newline separated, in
 // an ELF note with name "Go\x00\x00" and type 1. For GCCGO it is extracted from the
 // .go_export section.
-func readpkglist(shlibpath string) (pkgs []*load.Package) {
+func readpkglist(loaderstate *modload.State, shlibpath string) (pkgs []*load.Package) {
 	var stk load.ImportStack
 	if cfg.BuildToolchainName == "gccgo" {
 		f, err := elf.Open(shlibpath)
@@ -412,7 +413,7 @@ func readpkglist(shlibpath string) (pkgs []*load.Package) {
 		for _, line := range bytes.Split(data, []byte{'\n'}) {
 			if path, found := bytes.CutPrefix(line, pkgpath); found {
 				path = bytes.TrimSuffix(path, []byte{';'})
-				pkgs = append(pkgs, load.LoadPackageWithFlags(string(path), base.Cwd(), &stk, nil, 0))
+				pkgs = append(pkgs, load.LoadPackageWithFlags(loaderstate, string(path), base.Cwd(), &stk, nil, 0))
 			}
 		}
 	} else {
@@ -423,7 +424,7 @@ func readpkglist(shlibpath string) (pkgs []*load.Package) {
 		scanner := bufio.NewScanner(bytes.NewBuffer(pkglistbytes))
 		for scanner.Scan() {
 			t := scanner.Text()
-			pkgs = append(pkgs, load.LoadPackageWithFlags(t, base.Cwd(), &stk, nil, 0))
+			pkgs = append(pkgs, load.LoadPackageWithFlags(loaderstate, t, base.Cwd(), &stk, nil, 0))
 		}
 	}
 	return
@@ -445,7 +446,7 @@ func (b *Builder) cacheAction(mode string, p *load.Package, f func() *Action) *A
 // AutoAction returns the "right" action for go build or go install of p.
 func (b *Builder) AutoAction(mode, depMode BuildMode, p *load.Package) *Action {
 	if p.Name == "main" {
-		return b.LinkAction(mode, depMode, p)
+		return b.LinkAction(modload.LoaderState, mode, depMode, p)
 	}
 	return b.CompileAction(mode, depMode, p)
 }
@@ -913,7 +914,7 @@ func (b *Builder) vetAction(mode, depMode BuildMode, p *load.Package) *Action {
 // LinkAction returns the action for linking p into an executable
 // and possibly installing the result (according to mode).
 // depMode is the action (build or install) to use when compiling dependencies.
-func (b *Builder) LinkAction(mode, depMode BuildMode, p *load.Package) *Action {
+func (b *Builder) LinkAction(loaderstate *modload.State, mode, depMode BuildMode, p *load.Package) *Action {
 	// Construct link action.
 	a := b.cacheAction("link", p, func() *Action {
 		a := &Action{
@@ -948,7 +949,7 @@ func (b *Builder) LinkAction(mode, depMode BuildMode, p *load.Package) *Action {
 		}
 		a.Target = a.Objdir + filepath.Join("exe", name) + cfg.ExeSuffix
 		a.built = a.Target
-		b.addTransitiveLinkDeps(a, a1, "")
+		b.addTransitiveLinkDeps(loaderstate, a, a1, "")
 
 		// Sequence the build of the main package (a1) strictly after the build
 		// of all other dependencies that go into the link. It is likely to be after
@@ -1034,7 +1035,7 @@ func (b *Builder) installAction(a1 *Action, mode BuildMode) *Action {
 // makes sure those are present in a.Deps.
 // If shlib is non-empty, then a corresponds to the build and installation of shlib,
 // so any rebuild of shlib should not be added as a dependency.
-func (b *Builder) addTransitiveLinkDeps(a, a1 *Action, shlib string) {
+func (b *Builder) addTransitiveLinkDeps(loaderstate *modload.State, a, a1 *Action, shlib string) {
 	// Expand Deps to include all built packages, for the linker.
 	// Use breadth-first search to find rebuilt-for-test packages
 	// before the standard ones.
@@ -1075,7 +1076,7 @@ func (b *Builder) addTransitiveLinkDeps(a, a1 *Action, shlib string) {
 			// we'll end up building an overall library or executable that depends at runtime
 			// on other libraries that are out-of-date, which is clearly not good either.
 			// We call it ModeBuggyInstall to make clear that this is not right.
-			a.Deps = append(a.Deps, b.linkSharedAction(ModeBuggyInstall, ModeBuggyInstall, p1.Shlib, nil))
+			a.Deps = append(a.Deps, b.linkSharedAction(loaderstate, ModeBuggyInstall, ModeBuggyInstall, p1.Shlib, nil))
 		}
 	}
 }
@@ -1116,21 +1117,21 @@ func (b *Builder) buildmodeShared(mode, depMode BuildMode, args []string, pkgs [
 	if err != nil {
 		base.Fatalf("%v", err)
 	}
-	return b.linkSharedAction(mode, depMode, name, a1)
+	return b.linkSharedAction(modload.LoaderState, mode, depMode, name, a1)
 }
 
 // linkSharedAction takes a grouping action a1 corresponding to a list of built packages
 // and returns an action that links them together into a shared library with the name shlib.
 // If a1 is nil, shlib should be an absolute path to an existing shared library,
 // and then linkSharedAction reads that library to find out the package list.
-func (b *Builder) linkSharedAction(mode, depMode BuildMode, shlib string, a1 *Action) *Action {
+func (b *Builder) linkSharedAction(loaderstate *modload.State, mode, depMode BuildMode, shlib string, a1 *Action) *Action {
 	fullShlib := shlib
 	shlib = filepath.Base(shlib)
 	a := b.cacheAction("build-shlib "+shlib, nil, func() *Action {
 		if a1 == nil {
 			// TODO(rsc): Need to find some other place to store config,
 			// not in pkg directory. See golang.org/issue/22196.
-			pkgs := readpkglist(fullShlib)
+			pkgs := readpkglist(loaderstate, fullShlib)
 			a1 = &Action{
 				Mode: "shlib packages",
 			}
@@ -1173,7 +1174,7 @@ func (b *Builder) linkSharedAction(mode, depMode BuildMode, shlib string, a1 *Ac
 					}
 				}
 				var stk load.ImportStack
-				p := load.LoadPackageWithFlags(pkg, base.Cwd(), &stk, nil, 0)
+				p := load.LoadPackageWithFlags(loaderstate, pkg, base.Cwd(), &stk, nil, 0)
 				if p.Error != nil {
 					base.Fatalf("load %s: %v", pkg, p.Error)
 				}
@@ -1201,7 +1202,7 @@ func (b *Builder) linkSharedAction(mode, depMode BuildMode, shlib string, a1 *Ac
 				add(a, dep, true)
 			}
 		}
-		b.addTransitiveLinkDeps(a, a1, shlib)
+		b.addTransitiveLinkDeps(loaderstate, a, a1, shlib)
 		return a
 	})
 
diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index fdb483d46f21d9..45acbe85c2a6d0 100644
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -459,8 +459,8 @@ func oneMainPkg(pkgs []*load.Package) []*load.Package {
 var pkgsFilter = func(pkgs []*load.Package) []*load.Package { return pkgs }
 
 func runBuild(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
-	BuildInit()
+	modload.InitWorkfile(modload.LoaderState)
+	BuildInit(modload.LoaderState)
 	b := NewBuilder("")
 	defer func() {
 		if err := b.Close(); err != nil {
@@ -468,7 +468,7 @@ func runBuild(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	}()
 
-	pkgs := load.PackagesAndErrors(ctx, load.PackageOpts{AutoVCS: true}, args)
+	pkgs := load.PackagesAndErrors(modload.LoaderState, ctx, load.PackageOpts{AutoVCS: true}, args)
 	load.CheckPackageErrors(pkgs)
 
 	explicitO := len(cfg.BuildO) > 0
@@ -503,7 +503,7 @@ func runBuild(ctx context.Context, cmd *base.Command, args []string) {
 	}
 
 	if cfg.BuildCover {
-		load.PrepareForCoverageBuild(pkgs)
+		load.PrepareForCoverageBuild(modload.LoaderState, pkgs)
 	}
 
 	if cfg.BuildO != "" {
@@ -694,10 +694,10 @@ func runInstall(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	}
 
-	modload.InitWorkfile()
-	BuildInit()
-	pkgs := load.PackagesAndErrors(ctx, load.PackageOpts{AutoVCS: true}, args)
-	if cfg.ModulesEnabled && !modload.HasModRoot() {
+	modload.InitWorkfile(modload.LoaderState)
+	BuildInit(modload.LoaderState)
+	pkgs := load.PackagesAndErrors(modload.LoaderState, ctx, load.PackageOpts{AutoVCS: true}, args)
+	if cfg.ModulesEnabled && !modload.HasModRoot(modload.LoaderState) {
 		haveErrors := false
 		allMissingErrors := true
 		for _, pkg := range pkgs {
@@ -722,7 +722,7 @@ func runInstall(ctx context.Context, cmd *base.Command, args []string) {
 	load.CheckPackageErrors(pkgs)
 
 	if cfg.BuildCover {
-		load.PrepareForCoverageBuild(pkgs)
+		load.PrepareForCoverageBuild(modload.LoaderState, pkgs)
 	}
 
 	InstallPackages(ctx, args, pkgs)
@@ -861,9 +861,9 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
 func installOutsideModule(ctx context.Context, args []string) {
 	modload.LoaderState.ForceUseModules = true
 	modload.LoaderState.RootMode = modload.NoRoot
-	modload.AllowMissingModuleImports()
-	modload.Init()
-	BuildInit()
+	modload.AllowMissingModuleImports(modload.LoaderState)
+	modload.Init(modload.LoaderState)
+	BuildInit(modload.LoaderState)
 
 	// Load packages. Ignore non-main packages.
 	// Print a warning if an argument contains "..." and matches no main packages.
@@ -872,7 +872,7 @@ func installOutsideModule(ctx context.Context, args []string) {
 	// TODO(golang.org/issue/40276): don't report errors loading non-main packages
 	// matched by a pattern.
 	pkgOpts := load.PackageOpts{MainOnly: true}
-	pkgs, err := load.PackagesAndErrorsOutsideModule(ctx, pkgOpts, args)
+	pkgs, err := load.PackagesAndErrorsOutsideModule(modload.LoaderState, ctx, pkgOpts, args)
 	if err != nil {
 		base.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index 703b4367db31ef..eb012d26109f57 100644
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -2193,7 +2193,7 @@ func (noToolchain) cc(b *Builder, a *Action, ofile, cfile string) error {
 // gcc runs the gcc C compiler to create an object from a single C file.
 func (b *Builder) gcc(a *Action, workdir, out string, flags []string, cfile string) error {
 	p := a.Package
-	return b.ccompile(a, out, flags, cfile, b.GccCmd(p.Dir, workdir))
+	return b.ccompile(modload.LoaderState, a, out, flags, cfile, b.GccCmd(p.Dir, workdir))
 }
 
 // gas runs the gcc c compiler to create an object file from a single C assembly file.
@@ -2207,23 +2207,23 @@ func (b *Builder) gas(a *Action, workdir, out string, flags []string, sfile stri
 			return fmt.Errorf("package using cgo has Go assembly file %s", sfile)
 		}
 	}
-	return b.ccompile(a, out, flags, sfile, b.GccCmd(p.Dir, workdir))
+	return b.ccompile(modload.LoaderState, a, out, flags, sfile, b.GccCmd(p.Dir, workdir))
 }
 
 // gxx runs the g++ C++ compiler to create an object from a single C++ file.
 func (b *Builder) gxx(a *Action, workdir, out string, flags []string, cxxfile string) error {
 	p := a.Package
-	return b.ccompile(a, out, flags, cxxfile, b.GxxCmd(p.Dir, workdir))
+	return b.ccompile(modload.LoaderState, a, out, flags, cxxfile, b.GxxCmd(p.Dir, workdir))
 }
 
 // gfortran runs the gfortran Fortran compiler to create an object from a single Fortran file.
 func (b *Builder) gfortran(a *Action, workdir, out string, flags []string, ffile string) error {
 	p := a.Package
-	return b.ccompile(a, out, flags, ffile, b.gfortranCmd(p.Dir, workdir))
+	return b.ccompile(modload.LoaderState, a, out, flags, ffile, b.gfortranCmd(p.Dir, workdir))
 }
 
 // ccompile runs the given C or C++ compiler and creates an object from a single source file.
-func (b *Builder) ccompile(a *Action, outfile string, flags []string, file string, compiler []string) error {
+func (b *Builder) ccompile(loaderstate *modload.State, a *Action, outfile string, flags []string, file string, compiler []string) error {
 	p := a.Package
 	sh := b.Shell(a)
 	file = mkAbs(p.Dir, file)
@@ -2260,7 +2260,7 @@ func (b *Builder) ccompile(a *Action, outfile string, flags []string, file strin
 			} else if m.Dir == "" {
 				// The module is in the vendor directory. Replace the entire vendor
 				// directory path, because the module's Dir is not filled in.
-				from = modload.VendorDir()
+				from = modload.VendorDir(loaderstate)
 				toPath = "vendor"
 			} else {
 				from = m.Dir
@@ -2310,7 +2310,7 @@ func (b *Builder) ccompile(a *Action, outfile string, flags []string, file strin
 			}
 		}
 		if len(newFlags) < len(flags) {
-			return b.ccompile(a, outfile, newFlags, file, compiler)
+			return b.ccompile(loaderstate, a, outfile, newFlags, file, compiler)
 		}
 	}
 
@@ -3383,7 +3383,7 @@ func (b *Builder) swigDoIntSize(objdir string) (intsize string, err error) {
 	}
 	srcs := []string{src}
 
-	p := load.GoFilesPackage(context.TODO(), load.PackageOpts{}, srcs)
+	p := load.GoFilesPackage(modload.LoaderState, context.TODO(), load.PackageOpts{}, srcs)
 
 	if _, _, e := BuildToolchain.gc(b, &Action{Mode: "swigDoIntSize", Package: p, Objdir: objdir}, "", nil, nil, "", false, "", srcs); e != nil {
 		return "32", nil
diff --git a/src/cmd/go/internal/work/init.go b/src/cmd/go/internal/work/init.go
index e4e83dc8f9853e..a2954ab91ab60a 100644
--- a/src/cmd/go/internal/work/init.go
+++ b/src/cmd/go/internal/work/init.go
@@ -50,14 +50,14 @@ func makeCfgChangedEnv() []string {
 	return slices.Clip(env)
 }
 
-func BuildInit() {
+func BuildInit(loaderstate *modload.State) {
 	if buildInitStarted {
 		base.Fatalf("go: internal error: work.BuildInit called more than once")
 	}
 	buildInitStarted = true
 	base.AtExit(closeBuilders)
 
-	modload.Init()
+	modload.Init(loaderstate)
 	instrumentInit()
 	buildModeInit()
 	cfgChangedEnv = makeCfgChangedEnv()
diff --git a/src/cmd/go/internal/workcmd/edit.go b/src/cmd/go/internal/workcmd/edit.go
index 18730436ca8217..3778e70b687aec 100644
--- a/src/cmd/go/internal/workcmd/edit.go
+++ b/src/cmd/go/internal/workcmd/edit.go
@@ -143,8 +143,8 @@ func runEditwork(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) == 1 {
 		gowork = args[0]
 	} else {
-		modload.InitWorkfile()
-		gowork = modload.WorkFilePath()
+		modload.InitWorkfile(modload.LoaderState)
+		gowork = modload.WorkFilePath(modload.LoaderState)
 	}
 	if gowork == "" {
 		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
diff --git a/src/cmd/go/internal/workcmd/init.go b/src/cmd/go/internal/workcmd/init.go
index 52185391c115b3..20fef91d5e953c 100644
--- a/src/cmd/go/internal/workcmd/init.go
+++ b/src/cmd/go/internal/workcmd/init.go
@@ -44,11 +44,11 @@ func init() {
 }
 
 func runInit(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
+	modload.InitWorkfile(modload.LoaderState)
 
 	modload.LoaderState.ForceUseModules = true
 
-	gowork := modload.WorkFilePath()
+	gowork := modload.WorkFilePath(modload.LoaderState)
 	if gowork == "" {
 		gowork = filepath.Join(base.Cwd(), "go.work")
 	}
diff --git a/src/cmd/go/internal/workcmd/sync.go b/src/cmd/go/internal/workcmd/sync.go
index 640771d8f75996..c58cd55ceee392 100644
--- a/src/cmd/go/internal/workcmd/sync.go
+++ b/src/cmd/go/internal/workcmd/sync.go
@@ -49,8 +49,8 @@ func init() {
 
 func runSync(ctx context.Context, cmd *base.Command, args []string) {
 	modload.LoaderState.ForceUseModules = true
-	modload.InitWorkfile()
-	if modload.WorkFilePath() == "" {
+	modload.InitWorkfile(modload.LoaderState)
+	if modload.WorkFilePath(modload.LoaderState) == "" {
 		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
 	}
 
@@ -73,7 +73,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 	}
 	for _, m := range mms.Versions() {
 		opts.MainModule = m
-		_, pkgs := modload.LoadPackages(ctx, opts, "all")
+		_, pkgs := modload.LoadPackages(modload.LoaderState, ctx, opts, "all")
 		opts.MainModule = module.Version{} // reset
 
 		var (
@@ -91,7 +91,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 		mustSelectFor[m] = mustSelect
 	}
 
-	workFilePath := modload.WorkFilePath() // save go.work path because EnterModule clobbers it.
+	workFilePath := modload.WorkFilePath(modload.LoaderState) // save go.work path because EnterModule clobbers it.
 
 	var goV string
 	for _, m := range mms.Versions() {
@@ -114,12 +114,12 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 		// so we don't write some go.mods with the "before" toolchain
 		// and others with the "after" toolchain. If nothing else, that
 		// discrepancy could show up in auto-recorded toolchain lines.
-		changed, err := modload.EditBuildList(ctx, nil, mustSelectFor[m])
+		changed, err := modload.EditBuildList(modload.LoaderState, ctx, nil, mustSelectFor[m])
 		if err != nil {
 			continue
 		}
 		if changed {
-			modload.LoadPackages(ctx, modload.PackageOpts{
+			modload.LoadPackages(modload.LoaderState, ctx, modload.PackageOpts{
 				Tags:                     imports.AnyTags(),
 				Tidy:                     true,
 				VendorModulesInGOROOTSrc: true,
@@ -131,7 +131,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 			}, "all")
 			modload.WriteGoMod(ctx, modload.WriteOpts{})
 		}
-		goV = gover.Max(goV, modload.LoaderState.MainModules.GoVersion())
+		goV = gover.Max(goV, modload.LoaderState.MainModules.GoVersion(modload.LoaderState))
 	}
 
 	wf, err := modload.ReadWorkFile(workFilePath)
diff --git a/src/cmd/go/internal/workcmd/use.go b/src/cmd/go/internal/workcmd/use.go
index 2842163517892c..ca8de22cca884f 100644
--- a/src/cmd/go/internal/workcmd/use.go
+++ b/src/cmd/go/internal/workcmd/use.go
@@ -62,8 +62,8 @@ func init() {
 
 func runUse(ctx context.Context, cmd *base.Command, args []string) {
 	modload.LoaderState.ForceUseModules = true
-	modload.InitWorkfile()
-	gowork := modload.WorkFilePath()
+	modload.InitWorkfile(modload.LoaderState)
+	gowork := modload.WorkFilePath(modload.LoaderState)
 	if gowork == "" {
 		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
 	}
diff --git a/src/cmd/go/internal/workcmd/vendor.go b/src/cmd/go/internal/workcmd/vendor.go
index f9f0cc0898836f..36c1f7b522f9e7 100644
--- a/src/cmd/go/internal/workcmd/vendor.go
+++ b/src/cmd/go/internal/workcmd/vendor.go
@@ -46,8 +46,8 @@ func init() {
 }
 
 func runVendor(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile()
-	if modload.WorkFilePath() == "" {
+	modload.InitWorkfile(modload.LoaderState)
+	if modload.WorkFilePath(modload.LoaderState) == "" {
 		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
 	}
 

From 61d1ff61adb3febdbae21da7721b7cd5389efe4a Mon Sep 17 00:00:00 2001
From: Keith Randall 
Date: Wed, 8 Oct 2025 15:33:19 -0700
Subject: [PATCH 149/229] cmd/compile: use block starting position for phi line
 number

Fixes #75615

Change-Id: I2c7f0ea1203e8a97749c9f780c29a66050f0159d
Reviewed-on: https://go-review.googlesource.com/c/go/+/710355
Reviewed-by: Keith Randall 
Reviewed-by: David Chase 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/compile/internal/ssa/stmtlines_test.go | 12 ++++++------
 src/cmd/compile/internal/ssagen/phi.go         |  3 ++-
 src/cmd/compile/internal/ssagen/ssa.go         | 14 ++++++++++++++
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/stmtlines_test.go b/src/cmd/compile/internal/ssa/stmtlines_test.go
index 8cd11e9828e0f9..d0f09da86ffce2 100644
--- a/src/cmd/compile/internal/ssa/stmtlines_test.go
+++ b/src/cmd/compile/internal/ssa/stmtlines_test.go
@@ -137,17 +137,17 @@ func TestStmtLines(t *testing.T) {
 		}
 	}
 
-	var m int
+	var m float64
 	if runtime.GOARCH == "amd64" {
-		m = 1 // > 99% obtained on amd64, no backsliding
+		m = 0.011 // > 98.9% obtained on amd64, no backsliding
 	} else if runtime.GOARCH == "riscv64" {
-		m = 3 // XXX temporary update threshold to 97% for regabi
+		m = 0.03 // XXX temporary update threshold to 97% for regabi
 	} else {
-		m = 2 // expect 98% elsewhere.
+		m = 0.02 // expect 98% elsewhere.
 	}
 
-	if len(nonStmtLines)*100 > m*len(lines) {
-		t.Errorf("Saw too many (%s, > %d%%) lines without statement marks, total=%d, nostmt=%d ('-run TestStmtLines -v' lists failing lines)\n", runtime.GOARCH, m, len(lines), len(nonStmtLines))
+	if float64(len(nonStmtLines)) > m*float64(len(lines)) {
+		t.Errorf("Saw too many (%s, > %.1f%%) lines without statement marks, total=%d, nostmt=%d ('-run TestStmtLines -v' lists failing lines)\n", runtime.GOARCH, m*100, len(lines), len(nonStmtLines))
 	}
 	t.Logf("Saw %d out of %d lines without statement marks", len(nonStmtLines), len(lines))
 	if testing.Verbose() {
diff --git a/src/cmd/compile/internal/ssagen/phi.go b/src/cmd/compile/internal/ssagen/phi.go
index 19b6920913d83c..0dcf353bf43089 100644
--- a/src/cmd/compile/internal/ssagen/phi.go
+++ b/src/cmd/compile/internal/ssagen/phi.go
@@ -253,7 +253,7 @@ func (s *phiState) insertVarPhis(n int, var_ ir.Node, defs []*ssa.Block, typ *ty
 				}
 				// Add a phi to block c for variable n.
 				hasPhi.add(c.ID)
-				v := c.NewValue0I(currentRoot.Pos, ssa.OpPhi, typ, int64(n)) // TODO: line number right?
+				v := c.NewValue0I(s.s.blockStarts[b.ID], ssa.OpPhi, typ, int64(n))
 				// Note: we store the variable number in the phi's AuxInt field. Used temporarily by phi building.
 				if var_.Op() == ir.ONAME {
 					s.s.addNamedValue(var_.(*ir.Name), v)
@@ -513,6 +513,7 @@ loop:
 				v.Op = ssa.OpPhi
 				v.AddArgs(args...)
 				v.Aux = nil
+				v.Pos = s.s.blockStarts[b.ID]
 				continue loop
 			}
 			w = a // save witness
diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index e2ef33274577cc..ae7d57566f7e0d 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -1088,6 +1088,9 @@ type state struct {
 
 	// First argument of append calls that could be stack allocated.
 	appendTargets map[ir.Node]bool
+
+	// Block starting position, indexed by block id.
+	blockStarts []src.XPos
 }
 
 type funcLine struct {
@@ -1146,6 +1149,9 @@ func (s *state) startBlock(b *ssa.Block) {
 	s.curBlock = b
 	s.vars = map[ir.Node]*ssa.Value{}
 	clear(s.fwdVars)
+	for len(s.blockStarts) <= int(b.ID) {
+		s.blockStarts = append(s.blockStarts, src.NoXPos)
+	}
 }
 
 // endBlock marks the end of generating code for the current block.
@@ -1172,6 +1178,9 @@ func (s *state) endBlock() *ssa.Block {
 		b.Pos = src.NoXPos
 	} else {
 		b.Pos = s.lastPos
+		if s.blockStarts[b.ID] == src.NoXPos {
+			s.blockStarts[b.ID] = s.lastPos
+		}
 	}
 	return b
 }
@@ -1188,6 +1197,11 @@ func (s *state) pushLine(line src.XPos) {
 	} else {
 		s.lastPos = line
 	}
+	// The first position we see for a new block is its starting position
+	// (the line number for its phis, if any).
+	if b := s.curBlock; b != nil && s.blockStarts[b.ID] == src.NoXPos {
+		s.blockStarts[b.ID] = line
+	}
 
 	s.line = append(s.line, line)
 }

From 5c9a26c7f882dba5bfe10036815bcb239dd9b7e8 Mon Sep 17 00:00:00 2001
From: Vasily Leonenko 
Date: Fri, 25 Jul 2025 23:06:33 +0300
Subject: [PATCH 150/229] cmd/compile: use arm64 neon in
 LoweredMemmove/LoweredMemmoveLoop
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Raspberry Pi 5 (Cortex-A76)

                     │   base.log   │               opt.log               │
                     │    sec/op    │   sec/op     vs base                │
MemmoveKnownSize112     3.549n ± 0%   3.652n ± 0%   +2.92% (p=0.000 n=10)
MemmoveKnownSize128     3.979n ± 0%   3.617n ± 0%   -9.09% (p=0.000 n=10)
MemmoveKnownSize192     7.566n ± 0%   5.074n ± 0%  -32.94% (p=0.000 n=10)
MemmoveKnownSize248     8.549n ± 0%   7.184n ± 1%  -15.97% (p=0.000 n=10)
MemmoveKnownSize256    10.010n ± 0%   6.827n ± 0%  -31.80% (p=0.000 n=10)
MemmoveKnownSize512     19.81n ± 0%   13.59n ± 0%  -31.40% (p=0.000 n=10)
MemmoveKnownSize1024    39.66n ± 0%   27.00n ± 0%  -31.93% (p=0.000 n=10)
geomean                 9.538n        7.392n       -22.50%

Change-Id: I7b17408cd0a500ceaa80bc93ffe2f19ddeea9c0d
Reviewed-on: https://go-review.googlesource.com/c/go/+/692315
Reviewed-by: Keith Randall 
Reviewed-by: David Chase 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/compile/internal/arm64/ssa.go         | 89 ++++++++++++++-----
 src/cmd/compile/internal/ssa/_gen/ARM64Ops.go | 11 +--
 src/cmd/compile/internal/ssa/opGen.go         | 12 +--
 3 files changed, 79 insertions(+), 33 deletions(-)

diff --git a/src/cmd/compile/internal/arm64/ssa.go b/src/cmd/compile/internal/arm64/ssa.go
index 7bc0e536e941e6..43ecb6b4b715b4 100644
--- a/src/cmd/compile/internal/arm64/ssa.go
+++ b/src/cmd/compile/internal/arm64/ssa.go
@@ -1189,8 +1189,9 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		if dstReg == srcReg {
 			break
 		}
-		tmpReg1 := int16(arm64.REG_R24)
-		tmpReg2 := int16(arm64.REG_R25)
+		tmpReg1 := int16(arm64.REG_R25)
+		tmpFReg1 := int16(arm64.REG_F16)
+		tmpFReg2 := int16(arm64.REG_F17)
 		n := v.AuxInt
 		if n < 16 {
 			v.Fatalf("Move too small %d", n)
@@ -1198,10 +1199,17 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 
 		// Generate copying instructions.
 		var off int64
+		for n >= 32 {
+			//  FLDPQ   off(srcReg), (tmpFReg1, tmpFReg2)
+			//  FSTPQ   (tmpFReg1, tmpFReg2), off(dstReg)
+			move32(s, srcReg, dstReg, tmpFReg1, tmpFReg2, off, false)
+			off += 32
+			n -= 32
+		}
 		for n >= 16 {
-			// LDP     off(srcReg), (tmpReg1, tmpReg2)
-			// STP     (tmpReg1, tmpReg2), off(dstReg)
-			move16(s, srcReg, dstReg, tmpReg1, tmpReg2, off, false)
+			//  FMOVQ   off(src), tmpFReg1
+			//  FMOVQ   tmpFReg1, off(dst)
+			move16(s, srcReg, dstReg, tmpFReg1, off, false)
 			off += 16
 			n -= 16
 		}
@@ -1223,9 +1231,10 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		if dstReg == srcReg {
 			break
 		}
-		countReg := int16(arm64.REG_R23)
-		tmpReg1 := int16(arm64.REG_R24)
-		tmpReg2 := int16(arm64.REG_R25)
+		countReg := int16(arm64.REG_R24)
+		tmpReg1 := int16(arm64.REG_R25)
+		tmpFReg1 := int16(arm64.REG_F16)
+		tmpFReg2 := int16(arm64.REG_F17)
 		n := v.AuxInt
 		loopSize := int64(64)
 		if n < 3*loopSize {
@@ -1251,10 +1260,10 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 
 		// Move loopSize bytes starting at srcReg to dstReg.
 		// Increment srcReg and destReg by loopSize as a side effect.
-		for range loopSize / 16 {
-			// LDP.P  16(srcReg), (tmpReg1, tmpReg2)
-			// STP.P  (tmpReg1, tmpReg2), 16(dstReg)
-			move16(s, srcReg, dstReg, tmpReg1, tmpReg2, 0, true)
+		for range loopSize / 32 {
+			// FLDPQ.P 32(srcReg), (tmpFReg1, tmpFReg2)
+			// FSTPQ.P (tmpFReg1, tmpFReg2), 32(dstReg)
+			move32(s, srcReg, dstReg, tmpFReg1, tmpFReg2, 0, true)
 		}
 		// Decrement loop count.
 		//   SUB     $1, countReg
@@ -1276,10 +1285,17 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 
 		// Copy any fractional portion.
 		var off int64
+		for n >= 32 {
+			//  FLDPQ   off(srcReg), (tmpFReg1, tmpFReg2)
+			//  FSTPQ   (tmpFReg1, tmpFReg2), off(dstReg)
+			move32(s, srcReg, dstReg, tmpFReg1, tmpFReg2, off, false)
+			off += 32
+			n -= 32
+		}
 		for n >= 16 {
-			//  LDP     off(srcReg), (tmpReg1, tmpReg2)
-			//  STP     (tmpReg1, tmpReg2), off(dstReg)
-			move16(s, srcReg, dstReg, tmpReg1, tmpReg2, off, false)
+			//  FMOVQ   off(src), tmpFReg1
+			//  FMOVQ   tmpFReg1, off(dst)
+			move16(s, srcReg, dstReg, tmpFReg1, off, false)
 			off += 16
 			n -= 16
 		}
@@ -1699,26 +1715,55 @@ func zero8(s *ssagen.State, reg int16, off int64) {
 	p.To.Offset = off
 }
 
-// move16 copies 16 bytes at src+off to dst+off.
+// move32 copies 32 bytes at src+off to dst+off.
 // Uses registers tmp1 and tmp2.
-// If postInc is true, increment src and dst by 16.
-func move16(s *ssagen.State, src, dst, tmp1, tmp2 int16, off int64, postInc bool) {
-	// LDP     off(src), (tmp1, tmp2)
-	ld := s.Prog(arm64.ALDP)
+// If postInc is true, increment src and dst by 32.
+func move32(s *ssagen.State, src, dst, tmp1, tmp2 int16, off int64, postInc bool) {
+	// FLDPQ   off(src), (tmp1, tmp2)
+	ld := s.Prog(arm64.AFLDPQ)
 	ld.From.Type = obj.TYPE_MEM
 	ld.From.Reg = src
 	ld.From.Offset = off
 	ld.To.Type = obj.TYPE_REGREG
 	ld.To.Reg = tmp1
 	ld.To.Offset = int64(tmp2)
-	// STP     (tmp1, tmp2), off(dst)
-	st := s.Prog(arm64.ASTP)
+	// FSTPQ   (tmp1, tmp2), off(dst)
+	st := s.Prog(arm64.AFSTPQ)
 	st.From.Type = obj.TYPE_REGREG
 	st.From.Reg = tmp1
 	st.From.Offset = int64(tmp2)
 	st.To.Type = obj.TYPE_MEM
 	st.To.Reg = dst
 	st.To.Offset = off
+	if postInc {
+		if off != 0 {
+			panic("can't postinc with non-zero offset")
+		}
+		ld.Scond = arm64.C_XPOST
+		st.Scond = arm64.C_XPOST
+		ld.From.Offset = 32
+		st.To.Offset = 32
+	}
+}
+
+// move16 copies 16 bytes at src+off to dst+off.
+// Uses register tmp1
+// If postInc is true, increment src and dst by 16.
+func move16(s *ssagen.State, src, dst, tmp1 int16, off int64, postInc bool) {
+	// FMOVQ     off(src), tmp1
+	ld := s.Prog(arm64.AFMOVQ)
+	ld.From.Type = obj.TYPE_MEM
+	ld.From.Reg = src
+	ld.From.Offset = off
+	ld.To.Type = obj.TYPE_REG
+	ld.To.Reg = tmp1
+	// FMOVQ     tmp1, off(dst)
+	st := s.Prog(arm64.AFMOVQ)
+	st.From.Type = obj.TYPE_REG
+	st.From.Reg = tmp1
+	st.To.Type = obj.TYPE_MEM
+	st.To.Reg = dst
+	st.To.Offset = off
 	if postInc {
 		if off != 0 {
 			panic("can't postinc with non-zero offset")
diff --git a/src/cmd/compile/internal/ssa/_gen/ARM64Ops.go b/src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
index 43072ae9130ede..cc3758d10956d4 100644
--- a/src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
+++ b/src/cmd/compile/internal/ssa/_gen/ARM64Ops.go
@@ -144,8 +144,9 @@ func init() {
 		gpspsbg    = gpspg | buildReg("SB")
 		fp         = buildReg("F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F28 F29 F30 F31")
 		callerSave = gp | fp | buildReg("g") // runtime.setg (and anything calling it) may clobber g
+		r25        = buildReg("R25")
 		r24to25    = buildReg("R24 R25")
-		r23to25    = buildReg("R23 R24 R25")
+		f16to17    = buildReg("F16 F17")
 		rz         = buildReg("ZERO")
 		first16    = buildReg("R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15")
 	)
@@ -599,8 +600,8 @@ func init() {
 			aux:       "Int64",
 			argLength: 3,
 			reg: regInfo{
-				inputs:   []regMask{gp &^ r24to25, gp &^ r24to25},
-				clobbers: r24to25, // TODO: figure out needIntTemp x2
+				inputs:   []regMask{gp &^ r25, gp &^ r25},
+				clobbers: r25 | f16to17, // TODO: figure out needIntTemp + x2 for floats
 			},
 			faultOnNilArg0: true,
 			faultOnNilArg1: true,
@@ -617,8 +618,8 @@ func init() {
 			aux:       "Int64",
 			argLength: 3,
 			reg: regInfo{
-				inputs:       []regMask{gp &^ r23to25, gp &^ r23to25},
-				clobbers:     r23to25, // TODO: figure out needIntTemp x3
+				inputs:       []regMask{gp &^ r24to25, gp &^ r24to25},
+				clobbers:     r24to25 | f16to17, // TODO: figure out needIntTemp x2 + x2 for floats
 				clobbersArg0: true,
 				clobbersArg1: true,
 			},
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 9b38e66a23f019..061f1333382af4 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -23199,10 +23199,10 @@ var opcodeTable = [...]opInfo{
 		faultOnNilArg1: true,
 		reg: regInfo{
 			inputs: []inputInfo{
-				{0, 310378495}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R26 R30
-				{1, 310378495}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R26 R30
+				{0, 318767103}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R26 R30
+				{1, 318767103}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R26 R30
 			},
-			clobbers: 25165824, // R24 R25
+			clobbers: 422212481843200, // R25 F16 F17
 		},
 	},
 	{
@@ -23213,10 +23213,10 @@ var opcodeTable = [...]opInfo{
 		faultOnNilArg1: true,
 		reg: regInfo{
 			inputs: []inputInfo{
-				{0, 306184191}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R26 R30
-				{1, 306184191}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R26 R30
+				{0, 310378495}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R26 R30
+				{1, 310378495}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R26 R30
 			},
-			clobbers:     29360128, // R23 R24 R25
+			clobbers:     422212490231808, // R24 R25 F16 F17
 			clobbersArg0: true,
 			clobbersArg1: true,
 		},

From bb5eb5171535b9080055fee5996bd55398202124 Mon Sep 17 00:00:00 2001
From: matloob 
Date: Wed, 15 Oct 2025 12:52:47 -0400
Subject: [PATCH 151/229] runtime/pprof: fix errors in pprof_test

I think the original depth-1 argument to allocDeep was correct.
Reverted that, and also the change to maxSkip in mprof.go, which was
also incorrect. I think before we were usually passing accidentally in
the loop over matched stacks when we really should usually have been
passing in the previous loop.

Change-Id: I6a6a696463e2baf045b66f418d7afbfcb49258e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/712100
Reviewed-by: Michael Matloob 
TryBot-Bypass: Michael Matloob 
Reviewed-by: Michael Knyszek 
---
 src/runtime/mprof.go            | 2 +-
 src/runtime/pprof/pprof_test.go | 6 ++----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/runtime/mprof.go b/src/runtime/mprof.go
index 743fa5a3fe848b..794f57cee24a7c 100644
--- a/src/runtime/mprof.go
+++ b/src/runtime/mprof.go
@@ -49,7 +49,7 @@ const (
 	// desired maximum number of frames after expansion.
 	// This should be at least as large as the largest skip value
 	// used for profiling; otherwise stacks may be truncated inconsistently
-	maxSkip = 8
+	maxSkip = 6
 
 	// maxProfStackDepth is the highest valid value for debug.profstackdepth.
 	// It's used for the bucket.stk func.
diff --git a/src/runtime/pprof/pprof_test.go b/src/runtime/pprof/pprof_test.go
index 23d3cf585e59f1..b816833e52285f 100644
--- a/src/runtime/pprof/pprof_test.go
+++ b/src/runtime/pprof/pprof_test.go
@@ -2549,9 +2549,6 @@ func TestProfilerStackDepth(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.profiler, func(t *testing.T) {
-			if test.profiler == "heap" {
-				testenv.SkipFlaky(t, 74029)
-			}
 			var buf bytes.Buffer
 			if err := Lookup(test.profiler).WriteTo(&buf, 0); err != nil {
 				t.Fatalf("failed to write heap profile: %v", err)
@@ -2586,6 +2583,7 @@ func TestProfilerStackDepth(t *testing.T) {
 				t.Logf("matched stack=%s", stk)
 				if len(stk) != depth {
 					t.Errorf("want stack depth = %d, got %d", depth, len(stk))
+					continue
 				}
 
 				if rootFn, wantFn := stk[depth-1], "runtime/pprof.allocDeep"; rootFn != wantFn {
@@ -2663,7 +2661,7 @@ func goroutineDeep(t *testing.T, n int) {
 // guaranteed to have exactly the desired depth with produceProfileEvents as
 // their root frame which is expected by TestProfilerStackDepth.
 func produceProfileEvents(t *testing.T, depth int) {
-	allocDeep(depth + 1)       // +1 for produceProfileEvents, **
+	allocDeep(depth - 1)       // -1 for produceProfileEvents, **
 	blockChanDeep(t, depth-2)  // -2 for produceProfileEvents, **, chanrecv1
 	blockMutexDeep(t, depth-2) // -2 for produceProfileEvents, **, Unlock
 	memSink = nil

From b5a29cca486d26651e249c8395bc2df4a2d92d17 Mon Sep 17 00:00:00 2001
From: Alan Donovan 
Date: Wed, 15 Oct 2025 14:39:53 -0400
Subject: [PATCH 152/229] cmd/distpack: add fix tool to inventory

(To be consistent with change to build.go in CL 700795.)

For #71859

Change-Id: I8caad28b7e5a2657f21b60a72899daecf0b2c324
Reviewed-on: https://go-review.googlesource.com/c/go/+/712180
Auto-Submit: Alan Donovan 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
TryBot-Bypass: Alan Donovan 
---
 src/cmd/distpack/pack.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cmd/distpack/pack.go b/src/cmd/distpack/pack.go
index 6bab45f1d3d642..09c3a331195f58 100644
--- a/src/cmd/distpack/pack.go
+++ b/src/cmd/distpack/pack.go
@@ -172,7 +172,7 @@ func main() {
 			default:
 				return false
 			// Keep in sync with toolsIncludedInDistpack in cmd/dist/build.go.
-			case "asm", "cgo", "compile", "cover", "link", "preprofile", "vet":
+			case "asm", "cgo", "compile", "cover", "fix", "link", "preprofile", "vet":
 			}
 		}
 		return true

From 519ae514abace4551e0f99bf7da349a894b399b9 Mon Sep 17 00:00:00 2001
From: Youlin Feng 
Date: Tue, 26 Aug 2025 18:23:31 +0800
Subject: [PATCH 153/229] cmd/compile: eliminate bound check for slices of the
 same length

If two slices start out with the same length and decrease in length by
the same amount on each round of the loop (or in the if block), then
we think their length are always equal.

For example:

if len(a) != len(b) {
	return
}
for len(a) >= 4 {
	a = a[4:]
	b = b[4:] // proved here, omit boundary check
}
if len(a) == len(b) { // proved here
	//...
}

Or, change 'for' to 'if':

if len(a) != len(b) {
	return
}
if len(a) >= 4 {
	a = a[4:]
	b = b[4:]
}
if len(a) == len(b) { // proved here
	//...
}

Fixes #75144

Change-Id: I4e5902a02b5cf8fdc122715a7dbd2fb5e9a8f5dc
Reviewed-on: https://go-review.googlesource.com/c/go/+/699155
Reviewed-by: Michael Pratt 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Keith Randall 
---
 src/cmd/compile/internal/ssa/prove.go | 170 ++++++++++++++++++++++++++
 test/prove.go                         | 142 +++++++++++++++++++++
 2 files changed, 312 insertions(+)

diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go
index b4f91fd4fd12dc..c9bce23b286476 100644
--- a/src/cmd/compile/internal/ssa/prove.go
+++ b/src/cmd/compile/internal/ssa/prove.go
@@ -1240,6 +1240,173 @@ func (ft *factsTable) cleanup(f *Func) {
 	f.Cache.freeBoolSlice(ft.recurseCheck)
 }
 
+// addSlicesOfSameLen finds the slices that are in the same block and whose Op
+// is OpPhi and always have the same length, then add the equality relationship
+// between them to ft. If two slices start out with the same length and decrease
+// in length by the same amount on each round of the loop (or in the if block),
+// then we think their lengths are always equal.
+//
+// See https://go.dev/issues/75144
+//
+// In fact, we are just propagating the equality
+//
+//	if len(a) == len(b) { // from here
+//		for len(a) > 4 {
+//			a = a[4:]
+//			b = b[4:]
+//		}
+//		if len(a) == len(b) { // to here
+//			return true
+//		}
+//	}
+//
+// or change the for to if:
+//
+//	if len(a) == len(b) { // from here
+//		if len(a) > 4 {
+//			a = a[4:]
+//			b = b[4:]
+//		}
+//		if len(a) == len(b) { // to here
+//			return true
+//		}
+//	}
+func addSlicesOfSameLen(ft *factsTable, b *Block) {
+	// Let w points to the first value we're interested in, and then we
+	// only process those values ​​that appear to be the same length as w,
+	// looping only once. This should be enough in most cases. And u is
+	// similar to w, see comment for predIndex.
+	var u, w *Value
+	var i, j, k sliceInfo
+	isInterested := func(v *Value) bool {
+		j = getSliceInfo(v)
+		return j.sliceWhere != sliceUnknown
+	}
+	for _, v := range b.Values {
+		if v.Uses == 0 {
+			continue
+		}
+		if v.Op == OpPhi && len(v.Args) == 2 && ft.lens[v.ID] != nil && isInterested(v) {
+			if j.predIndex == 1 && ft.lens[v.Args[0].ID] != nil {
+				// found v = (Phi x (SliceMake _ (Add64 (Const64 [n]) (SliceLen x)) _))) or
+				// v = (Phi x (SliceMake _ (Add64 (Const64 [n]) (SliceLen v)) _)))
+				if w == nil {
+					k = j
+					w = v
+					continue
+				}
+				// propagate the equality
+				if j == k && ft.orderS.Equal(ft.lens[v.Args[0].ID], ft.lens[w.Args[0].ID]) {
+					ft.update(b, ft.lens[v.ID], ft.lens[w.ID], signed, eq)
+				}
+			} else if j.predIndex == 0 && ft.lens[v.Args[1].ID] != nil {
+				// found v = (Phi (SliceMake _ (Add64 (Const64 [n]) (SliceLen x)) _)) x) or
+				// v = (Phi (SliceMake _ (Add64 (Const64 [n]) (SliceLen v)) _)) x)
+				if u == nil {
+					i = j
+					u = v
+					continue
+				}
+				// propagate the equality
+				if j == i && ft.orderS.Equal(ft.lens[v.Args[1].ID], ft.lens[u.Args[1].ID]) {
+					ft.update(b, ft.lens[v.ID], ft.lens[u.ID], signed, eq)
+				}
+			}
+		}
+	}
+}
+
+type sliceWhere int
+
+const (
+	sliceUnknown sliceWhere = iota
+	sliceInFor
+	sliceInIf
+)
+
+// predIndex is used to indicate the branch represented by the predecessor
+// block in which the slicing operation occurs.
+type predIndex int
+
+type sliceInfo struct {
+	lengthDiff int64
+	sliceWhere
+	predIndex
+}
+
+// getSliceInfo returns the negative increment of the slice length in a slice
+// operation by examine the Phi node at the merge block. So, we only interest
+// in the slice operation if it is inside a for block or an if block.
+// Otherwise it returns sliceInfo{0, sliceUnknown, 0}.
+//
+// For the following for block:
+//
+//	for len(a) > 4 {
+//	    a = a[4:]
+//	}
+//
+// vp = (Phi v3 v9)
+// v5 = (SliceLen vp)
+// v7 = (Add64 (Const64 [-4]) v5)
+// v9 = (SliceMake _ v7 _)
+//
+// returns sliceInfo{-4, sliceInFor, 1}
+//
+// For a subsequent merge block after an if block:
+//
+//	if len(a) > 4 {
+//	    a = a[4:]
+//	}
+//	a // here
+//
+// vp = (Phi v3 v9)
+// v5 = (SliceLen v3)
+// v7 = (Add64 (Const64 [-4]) v5)
+// v9 = (SliceMake _ v7 _)
+//
+// returns sliceInfo{-4, sliceInIf, 1}
+//
+// Returns sliceInfo{0, sliceUnknown, 0} if it is not the slice
+// operation we are interested in.
+func getSliceInfo(vp *Value) (inf sliceInfo) {
+	if vp.Op != OpPhi || len(vp.Args) != 2 {
+		return
+	}
+	var i predIndex
+	var l *Value // length for OpSliceMake
+	if vp.Args[0].Op != OpSliceMake && vp.Args[1].Op == OpSliceMake {
+		l = vp.Args[1].Args[1]
+		i = 1
+	} else if vp.Args[0].Op == OpSliceMake && vp.Args[1].Op != OpSliceMake {
+		l = vp.Args[0].Args[1]
+		i = 0
+	} else {
+		return
+	}
+	var op Op
+	switch l.Op {
+	case OpAdd64:
+		op = OpConst64
+	case OpAdd32:
+		op = OpConst32
+	default:
+		return
+	}
+	if l.Args[0].Op == op && l.Args[1].Op == OpSliceLen && l.Args[1].Args[0] == vp {
+		return sliceInfo{l.Args[0].AuxInt, sliceInFor, i}
+	}
+	if l.Args[1].Op == op && l.Args[0].Op == OpSliceLen && l.Args[0].Args[0] == vp {
+		return sliceInfo{l.Args[1].AuxInt, sliceInFor, i}
+	}
+	if l.Args[0].Op == op && l.Args[1].Op == OpSliceLen && l.Args[1].Args[0] == vp.Args[1-i] {
+		return sliceInfo{l.Args[0].AuxInt, sliceInIf, i}
+	}
+	if l.Args[1].Op == op && l.Args[0].Op == OpSliceLen && l.Args[0].Args[0] == vp.Args[1-i] {
+		return sliceInfo{l.Args[1].AuxInt, sliceInIf, i}
+	}
+	return
+}
+
 // prove removes redundant BlockIf branches that can be inferred
 // from previous dominating comparisons.
 //
@@ -1505,6 +1672,9 @@ func prove(f *Func) {
 				addBranchRestrictions(ft, parent, branch)
 			}
 
+			// Add slices of the same length start from current block.
+			addSlicesOfSameLen(ft, node.block)
+
 			if ft.unsat {
 				// node.block is unreachable.
 				// Remove it and don't visit
diff --git a/test/prove.go b/test/prove.go
index bcc023dfec62fd..c48280aa31e7b5 100644
--- a/test/prove.go
+++ b/test/prove.go
@@ -2342,6 +2342,148 @@ func setCapMaxBasedOnElementSize(x []uint64) int {
 	return 0
 }
 
+func issue75144for(a, b []uint64) bool {
+	if len(a) == len(b) {
+		for len(a) > 4 {
+			a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			b = b[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+		}
+		if len(a) == len(b) { // ERROR "Proved Eq64$"
+			return true
+		}
+	}
+	return false
+}
+
+func issue75144if(a, b []uint64) bool {
+	if len(a) == len(b) {
+		if len(a) > 4 {
+			a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			b = b[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+		}
+		if len(a) == len(b) { // ERROR "Proved Eq64$"
+			return true
+		}
+	}
+	return false
+}
+
+func issue75144if2(a, b, c, d []uint64) (r bool) {
+	if len(a) != len(b) || len(c) != len(d) {
+		return
+	}
+	if len(a) <= 4 || len(c) <= 4 {
+		return
+	}
+	if len(a) < len(c) {
+		c = c[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+		d = d[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+	} else {
+		a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+		b = b[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+	}
+	if len(a) == len(c) {
+		return
+	}
+	if len(a) == len(b) { // ERROR "Proved Eq64$"
+		r = true
+	}
+	if len(c) == len(d) { // ERROR "Proved Eq64$"
+		r = true
+	}
+	return
+}
+
+func issue75144forCannot(a, b []uint64) bool {
+	if len(a) == len(b) {
+		for len(a) > 4 {
+			a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			b = b[4:]
+			for len(a) > 2 {
+				a = a[2:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+				b = b[2:]
+			}
+		}
+		if len(a) == len(b) {
+			return true
+		}
+	}
+	return false
+}
+
+func issue75144ifCannot(a, b []uint64) bool {
+	if len(a) == len(b) {
+		if len(a) > 4 {
+			a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			b = b[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			if len(a) > 2 {
+				a = a[2:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+				b = b[2:]
+			}
+		}
+		if len(a) == len(b) {
+			return true
+		}
+	}
+	return false
+}
+
+func issue75144ifCannot2(a, b []uint64) bool {
+	if len(a) == len(b) {
+		if len(a) > 4 {
+			a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			b = b[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+		} else if len(a) > 2 {
+			a = a[2:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			b = b[2:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+		}
+		if len(a) == len(b) {
+			return true
+		}
+	}
+	return false
+}
+
+func issue75144forNot(a, b []uint64) bool {
+	if len(a) == len(b) {
+		for len(a) > 4 {
+			a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			b = b[3:]
+		}
+		if len(a) == len(b) {
+			return true
+		}
+	}
+	return false
+}
+
+func issue75144forNot2(a, b, c []uint64) bool {
+	if len(a) == len(b) {
+		for len(a) > 4 {
+			a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+			b = c[4:]
+		}
+		if len(a) == len(b) {
+			return true
+		}
+	}
+	return false
+}
+
+func issue75144ifNot(a, b []uint64) bool {
+	if len(a) == len(b) {
+		if len(a) > 4 {
+			a = a[4:] // ERROR "Proved slicemask not needed$" "Proved IsSliceInBounds$"
+		} else {
+			b = b[4:]
+		}
+		if len(a) == len(b) {
+			return true
+		}
+	}
+	return false
+}
+
 //go:noinline
 func useInt(a int) {
 }

From 284379cdfcbd6971f46616a3c66bf19e467fdf0d Mon Sep 17 00:00:00 2001
From: Alexander Musman 
Date: Sun, 28 Sep 2025 18:48:46 +0300
Subject: [PATCH 154/229] cmd/compile: remove rematerializable values from live
 set across calls
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Remove rematerializable values in the live set across call operations,
preventing dead constant rematerialization.

When computing live values across function calls, rematerializable
values were being kept in the live set unnecessarily. This caused
the shuffling to rematerialize dead constants.

This change leads to code size reduction on arm64 linux:
    Executable            Old .text  New .text     Change
    -------------------------------------------------------
    asm                     1969236    1964356     -0.25%
    cgo                     1739588    1734884     -0.27%
    compile                 8950788    8932500     -0.20%
    cover                   1877268    1872916     -0.23%
    link                    2572660    2565076     -0.29%
    preprofile               866772     863828     -0.34%
    vet                     2888628    2881028     -0.26%

There seems also some compile time effect:

                        orig.results             uexp.results
                           sec/op       sec/op     vs base
BleveIndexBatch100-4       7.414 ± 2%    7.352 ± 1%       ~ (p=0.218 n=10)
ESBuildThreeJS-4          777.3m ± 1%   778.1m ± 1%       ~ (p=0.529 n=10)
ESBuildRomeTS-4           197.3m ± 1%   199.0m ± 1%       ~ (p=0.143 n=10)
EtcdPut-4                 64.92m ± 2%   64.95m ± 2%       ~ (p=0.912 n=10)
EtcdSTM-4                 323.9m ± 1%   323.0m ± 1%       ~ (p=0.393 n=10)
GoBuildKubelet-4           160.1 ± 0%    159.4 ± 0%  -0.42% (p=0.001 n=10)
GoBuildKubeletLink-4       12.40 ± 1%    12.27 ± 1%       ~ (p=0.529 n=10)
GoBuildIstioctl-4          125.8 ± 0%    125.2 ± 0%  -0.42% (p=0.000 n=10)
GoBuildIstioctlLink-4      8.679 ± 0%    8.686 ± 1%       ~ (p=0.912 n=10)
GoBuildFrontend-4          49.18 ± 0%    48.73 ± 0%  -0.92% (p=0.000 n=10)
GoBuildFrontendLink-4      2.300 ± 1%    2.292 ± 1%  -0.35% (p=0.043 n=10)
GopherLuaKNucleotide-4     37.77 ± 6%    38.07 ± 2%       ~ (p=0.218 n=10)
MarkdownRenderXHTML-4     274.3m ± 0%   275.2m ± 0%  +0.34% (p=0.003 n=10)
Tile38QueryLoad-4         650.7µ ± 0%   650.2µ ± 0%       ~ (p=0.971 n=10)
geomean                    2.130         2.127       -0.15%

Change-Id: I7a766195ee17bfd9e47d7a940864619f553416ff
Reviewed-on: https://go-review.googlesource.com/c/go/+/707415
Reviewed-by: Dmitri Shuralyov 
Reviewed-by: Keith Randall 
Auto-Submit: Keith Randall 
Reviewed-by: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/compile/internal/ssa/regalloc.go      | 12 ++++++
 src/cmd/compile/internal/ssa/regalloc_test.go | 42 +++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go
index e959b8ed7df2eb..0009de4fa69608 100644
--- a/src/cmd/compile/internal/ssa/regalloc.go
+++ b/src/cmd/compile/internal/ssa/regalloc.go
@@ -2806,6 +2806,7 @@ func (s *regAllocState) computeLive() {
 	s.live = make([][]liveInfo, f.NumBlocks())
 	s.desired = make([]desiredState, f.NumBlocks())
 	var phis []*Value
+	rematIDs := make([]ID, 0, 64)
 
 	live := f.newSparseMapPos(f.NumValues())
 	defer f.retSparseMapPos(live)
@@ -2858,9 +2859,20 @@ func (s *regAllocState) computeLive() {
 					continue
 				}
 				if opcodeTable[v.Op].call {
+					rematIDs = rematIDs[:0]
 					c := live.contents()
 					for i := range c {
 						c[i].val += unlikelyDistance
+						vid := c[i].key
+						if s.values[vid].rematerializeable {
+							rematIDs = append(rematIDs, vid)
+						}
+					}
+					// We don't spill rematerializeable values, and assuming they
+					// are live across a call would only force shuffle to add some
+					// (dead) constant rematerialization. Remove them.
+					for _, r := range rematIDs {
+						live.remove(r)
 					}
 				}
 				for _, a := range v.Args {
diff --git a/src/cmd/compile/internal/ssa/regalloc_test.go b/src/cmd/compile/internal/ssa/regalloc_test.go
index 79f94da0114f93..12f5820f1ff81d 100644
--- a/src/cmd/compile/internal/ssa/regalloc_test.go
+++ b/src/cmd/compile/internal/ssa/regalloc_test.go
@@ -265,6 +265,48 @@ func TestClobbersArg1(t *testing.T) {
 	}
 }
 
+func TestNoRematerializeDeadConstant(t *testing.T) {
+	c := testConfigARM64(t)
+	f := c.Fun("b1",
+		Bloc("b1",
+			Valu("mem", OpInitMem, types.TypeMem, 0, nil),
+			Valu("addr", OpArg, c.config.Types.Int32.PtrTo(), 0, c.Temp(c.config.Types.Int32.PtrTo())),
+			Valu("const", OpARM64MOVDconst, c.config.Types.Int32, -1, nil), // Original constant
+			Valu("cmp", OpARM64CMPconst, types.TypeFlags, 0, nil, "const"),
+			Goto("b2"),
+		),
+		Bloc("b2",
+			Valu("phi_mem", OpPhi, types.TypeMem, 0, nil, "mem", "callmem"),
+			Eq("cmp", "b6", "b3"),
+		),
+		Bloc("b3",
+			Valu("call", OpARM64CALLstatic, types.TypeMem, 0, AuxCallLSym("_"), "phi_mem"),
+			Valu("callmem", OpSelectN, types.TypeMem, 0, nil, "call"),
+			Eq("cmp", "b5", "b4"),
+		),
+		Bloc("b4", // A block where we don't really need to rematerialize the constant -1
+			Goto("b2"),
+		),
+		Bloc("b5",
+			Valu("user", OpAMD64MOVQstore, types.TypeMem, 0, nil, "addr", "const", "callmem"),
+			Exit("user"),
+		),
+		Bloc("b6",
+			Exit("phi_mem"),
+		),
+	)
+
+	regalloc(f.f)
+	checkFunc(f.f)
+
+	// Check that in block b4, there's no dead rematerialization of the constant -1
+	for _, v := range f.blocks["b4"].Values {
+		if v.Op == OpARM64MOVDconst && v.AuxInt == -1 {
+			t.Errorf("constant -1 rematerialized in loop block b4: %s", v.LongString())
+		}
+	}
+}
+
 func numSpills(b *Block) int {
 	return numOps(b, OpStoreReg)
 }

From 6346349f5629a5767d2cd132f01092857a570bd2 Mon Sep 17 00:00:00 2001
From: Will Faught 
Date: Sat, 20 Sep 2025 21:36:14 +0000
Subject: [PATCH 155/229] cmd/compile: replace angle brackets with square

Caused Markdown rendering error on https://go.dev/src/cmd/compile/README in macOS (15.6.1) Safari (18.6).

Change-Id: Id71436d9a7bc7e461e522500d66df5dda7cd9f7f
GitHub-Last-Rev: 4e4447e163ac65e6c394807ec4874bc5ca26bb32
GitHub-Pull-Request: golang/go#75549
Reviewed-on: https://go-review.googlesource.com/c/go/+/704716
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Auto-Submit: Dmitri Shuralyov 
Reviewed-by: Dmitri Shuralyov 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cmd/compile/README.md b/src/cmd/compile/README.md
index 1089348030d78b..02429d5688659e 100644
--- a/src/cmd/compile/README.md
+++ b/src/cmd/compile/README.md
@@ -289,9 +289,9 @@ dependencies, so is not suitable for distributed build systems.)
   ```
   After that, your edit/compile/test cycle can be similar to:
   ```
-  <... make edits to cmd/compile source ...>
+  [... make edits to cmd/compile source ...]
   $ toolstash restore && go install cmd/compile   # restore known good tools to build compiler
-  <... 'go build', 'go test', etc. ...>           # use freshly built compiler
+  [... 'go build', 'go test', etc. ...]           # use freshly built compiler
   ```
 
 * toolstash also allows comparing the installed vs. stashed copy of

From 31f82877e85a7e6c70b0104e704abfed622e345f Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Wed, 15 Oct 2025 11:27:17 -0700
Subject: [PATCH 156/229] go/types, types2: fix misleading internal comment

See also the discussion in #75885.

Change-Id: Ieb964ea6ee51600c0c08ecba0af50a1deb209a4d
Reviewed-on: https://go-review.googlesource.com/c/go/+/712141
Reviewed-by: Mark Freeman 
Auto-Submit: Robert Griesemer 
TryBot-Bypass: Robert Griesemer 
Reviewed-by: Robert Griesemer 
---
 src/cmd/compile/internal/types2/decl.go | 7 ++-----
 src/go/types/decl.go                    | 7 ++-----
 2 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/src/cmd/compile/internal/types2/decl.go b/src/cmd/compile/internal/types2/decl.go
index 4ebd9454070757..22fccc15199e87 100644
--- a/src/cmd/compile/internal/types2/decl.go
+++ b/src/cmd/compile/internal/types2/decl.go
@@ -575,11 +575,8 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *TypeN
 		named.underlying = Typ[Invalid]
 	}
 
-	// Disallow a lone type parameter as the RHS of a type declaration (go.dev/issue/45639).
-	// We don't need this restriction anymore if we make the underlying type of a type
-	// parameter its constraint interface: if the RHS is a lone type parameter, we will
-	// use its underlying type (like we do for any RHS in a type declaration), and its
-	// underlying type is an interface and the type declaration is well defined.
+	// spec: "In a type definition the given type cannot be a type parameter."
+	// (See also go.dev/issue/45639.)
 	if isTypeParam(rhs) {
 		check.error(tdecl.Type, MisplacedTypeParam, "cannot use a type parameter as RHS in type declaration")
 		named.underlying = Typ[Invalid]
diff --git a/src/go/types/decl.go b/src/go/types/decl.go
index aef7f6ad0b9099..13d9d9ce57499c 100644
--- a/src/go/types/decl.go
+++ b/src/go/types/decl.go
@@ -657,11 +657,8 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *ast.TypeSpec, def *TypeName
 		named.underlying = Typ[Invalid]
 	}
 
-	// Disallow a lone type parameter as the RHS of a type declaration (go.dev/issue/45639).
-	// We don't need this restriction anymore if we make the underlying type of a type
-	// parameter its constraint interface: if the RHS is a lone type parameter, we will
-	// use its underlying type (like we do for any RHS in a type declaration), and its
-	// underlying type is an interface and the type declaration is well defined.
+	// spec: "In a type definition the given type cannot be a type parameter."
+	// (See also go.dev/issue/45639.)
 	if isTypeParam(rhs) {
 		check.error(tdecl.Type, MisplacedTypeParam, "cannot use a type parameter as RHS in type declaration")
 		named.underlying = Typ[Invalid]

From 0984dcd7572a90a1bd21bec98bd9c73fdcf983ab Mon Sep 17 00:00:00 2001
From: mohanson 
Date: Wed, 15 Oct 2025 10:27:16 +0800
Subject: [PATCH 157/229] cmd/compile: fix an error in comments

Remove the redundant only.

Change-Id: I9cf2d84ae080a567ad45a2d0ef002c7c89395479
Reviewed-on: https://go-review.googlesource.com/c/go/+/711960
Auto-Submit: Robert Findley 
Reviewed-by: Robert Griesemer 
Reviewed-by: Robert Findley 
TryBot-Bypass: Robert Griesemer 
---
 src/cmd/compile/internal/types2/instantiate.go | 2 +-
 src/go/types/instantiate.go                    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cmd/compile/internal/types2/instantiate.go b/src/cmd/compile/internal/types2/instantiate.go
index 1c8c12d07cfafa..8b24f2fc685b81 100644
--- a/src/cmd/compile/internal/types2/instantiate.go
+++ b/src/cmd/compile/internal/types2/instantiate.go
@@ -83,7 +83,7 @@ func Instantiate(ctxt *Context, orig Type, targs []Type, validate bool) (Type, e
 //
 // For Named types the resulting instance may be unexpanded.
 //
-// check may be nil (when not type-checking syntax); pos is used only only if check is non-nil.
+// check may be nil (when not type-checking syntax); pos is used only if check is non-nil.
 func (check *Checker) instance(pos syntax.Pos, orig genericType, targs []Type, expanding *Named, ctxt *Context) (res Type) {
 	// The order of the contexts below matters: we always prefer instances in the
 	// expanding instance context in order to preserve reference cycles.
diff --git a/src/go/types/instantiate.go b/src/go/types/instantiate.go
index eef473447da414..0bccd3dff6b02c 100644
--- a/src/go/types/instantiate.go
+++ b/src/go/types/instantiate.go
@@ -86,7 +86,7 @@ func Instantiate(ctxt *Context, orig Type, targs []Type, validate bool) (Type, e
 //
 // For Named types the resulting instance may be unexpanded.
 //
-// check may be nil (when not type-checking syntax); pos is used only only if check is non-nil.
+// check may be nil (when not type-checking syntax); pos is used only if check is non-nil.
 func (check *Checker) instance(pos token.Pos, orig genericType, targs []Type, expanding *Named, ctxt *Context) (res Type) {
 	// The order of the contexts below matters: we always prefer instances in the
 	// expanding instance context in order to preserve reference cycles.

From f1fed742ebbe781611c9f78398d9fa233ad0a8e6 Mon Sep 17 00:00:00 2001
From: Alan Donovan 
Date: Wed, 15 Oct 2025 16:28:03 -0400
Subject: [PATCH 158/229] cmd: fix three printf problems reported by newest vet

Change-Id: Id70985d217c940eb022dbc95bfaa20373672512c
Reviewed-on: https://go-review.googlesource.com/c/go/+/712220
Auto-Submit: Alan Donovan 
TryBot-Bypass: Alan Donovan 
Commit-Queue: Alan Donovan 
Reviewed-by: Cherry Mui 
---
 src/cmd/go/internal/modload/vendor.go | 2 +-
 src/cmd/internal/obj/loong64/asm.go   | 2 +-
 src/cmd/internal/obj/riscv/obj.go     | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/cmd/go/internal/modload/vendor.go b/src/cmd/go/internal/modload/vendor.go
index bf0c4e403717a6..1fc20ad398b363 100644
--- a/src/cmd/go/internal/modload/vendor.go
+++ b/src/cmd/go/internal/modload/vendor.go
@@ -188,7 +188,7 @@ func checkVendorConsistency(loaderstate *State, indexes []*modFileIndex, modFile
 					// However, we can at least detect a version mismatch if packages were
 					// vendored from a non-matching version.
 					if vv, ok := vendorVersion[r.Mod.Path]; ok && vv != r.Mod.Version {
-						vendErrorf(r.Mod, fmt.Sprintf("is explicitly required in go.mod, but vendor/modules.txt indicates %s@%s", r.Mod.Path, vv))
+						vendErrorf(r.Mod, "is explicitly required in go.mod, but vendor/modules.txt indicates %s@%s", r.Mod.Path, vv)
 					}
 				} else {
 					vendErrorf(r.Mod, "is explicitly required in go.mod, but not marked as explicit in vendor/modules.txt")
diff --git a/src/cmd/internal/obj/loong64/asm.go b/src/cmd/internal/obj/loong64/asm.go
index ccf093ca9e8d54..5a61acac8741d6 100644
--- a/src/cmd/internal/obj/loong64/asm.go
+++ b/src/cmd/internal/obj/loong64/asm.go
@@ -4438,7 +4438,7 @@ func (c *ctxt0) specialFpMovInst(a obj.As, fclass int, tclass int) uint32 {
 		}
 	}
 
-	c.ctxt.Diag("bad class combination: %s %d,%s\n", a, fclass, tclass)
+	c.ctxt.Diag("bad class combination: %s %d,%d\n", a, fclass, tclass)
 
 	return 0
 }
diff --git a/src/cmd/internal/obj/riscv/obj.go b/src/cmd/internal/obj/riscv/obj.go
index 4a9c54a3967c4e..74699cc398534e 100644
--- a/src/cmd/internal/obj/riscv/obj.go
+++ b/src/cmd/internal/obj/riscv/obj.go
@@ -2991,7 +2991,7 @@ func (ins *instruction) length() int {
 func (ins *instruction) validate(ctxt *obj.Link) {
 	enc, err := encodingForAs(ins.as)
 	if err != nil {
-		ctxt.Diag(err.Error())
+		ctxt.Diag("%v", err)
 		return
 	}
 	enc.validate(ctxt, ins)

From b68cebd809f1335b4504837337f5702406720432 Mon Sep 17 00:00:00 2001
From: Damien Neil 
Date: Tue, 14 Oct 2025 11:25:29 -0700
Subject: [PATCH 159/229] net/http/httptest: record failed ResponseWriter
 writes

CL 709335 changed ResponseWriter.Write to return an error
when trying to write to a response with a status code which
doesn't permit a body, such as 304.

Continue to return an error, but still record the write in
ResponseWriter.Body. This maintains the documented property that
"the data in buf is written to rw.Body".

For #75471

Change-Id: I69139797559fe09d6580c5d25b4458f04263c60e
Reviewed-on: https://go-review.googlesource.com/c/go/+/711940
Reviewed-by: Sean Liao 
TryBot-Bypass: Damien Neil 
Auto-Submit: Damien Neil 
Reviewed-by: Nicholas Husin 
Reviewed-by: Nicholas Husin 
---
 src/net/http/httptest/recorder.go      | 16 ++++++++--------
 src/net/http/httptest/recorder_test.go | 10 ++++++++--
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/net/http/httptest/recorder.go b/src/net/http/httptest/recorder.go
index 7890b5ef6bdf31..4006f4406d27a5 100644
--- a/src/net/http/httptest/recorder.go
+++ b/src/net/http/httptest/recorder.go
@@ -105,28 +105,28 @@ func (rw *ResponseRecorder) writeHeader(b []byte, str string) {
 // Write implements http.ResponseWriter. The data in buf is written to
 // rw.Body, if not nil.
 func (rw *ResponseRecorder) Write(buf []byte) (int, error) {
-	code := rw.Code
-	if !bodyAllowedForStatus(code) {
-		return 0, http.ErrBodyNotAllowed
-	}
+	// Record the write, even if we're going to return an error.
 	rw.writeHeader(buf, "")
 	if rw.Body != nil {
 		rw.Body.Write(buf)
 	}
+	if !bodyAllowedForStatus(rw.Code) {
+		return 0, http.ErrBodyNotAllowed
+	}
 	return len(buf), nil
 }
 
 // WriteString implements [io.StringWriter]. The data in str is written
 // to rw.Body, if not nil.
 func (rw *ResponseRecorder) WriteString(str string) (int, error) {
-	code := rw.Code
-	if !bodyAllowedForStatus(code) {
-		return 0, http.ErrBodyNotAllowed
-	}
+	// Record the write, even if we're going to return an error.
 	rw.writeHeader(nil, str)
 	if rw.Body != nil {
 		rw.Body.WriteString(str)
 	}
+	if !bodyAllowedForStatus(rw.Code) {
+		return 0, http.ErrBodyNotAllowed
+	}
 	return len(str), nil
 }
 
diff --git a/src/net/http/httptest/recorder_test.go b/src/net/http/httptest/recorder_test.go
index abf8e118d6092e..099697651465ad 100644
--- a/src/net/http/httptest/recorder_test.go
+++ b/src/net/http/httptest/recorder_test.go
@@ -5,6 +5,7 @@
 package httptest
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -312,17 +313,22 @@ func TestRecorder(t *testing.T) {
 
 func TestBodyNotAllowed(t *testing.T) {
 	rw := NewRecorder()
+	rw.Body = new(bytes.Buffer)
 	rw.WriteHeader(204)
 
-	_, err := rw.Write([]byte("hello world"))
+	_, err := rw.Write([]byte("hello "))
 	if !errors.Is(err, http.ErrBodyNotAllowed) {
 		t.Errorf("expected BodyNotAllowed for Write after 204, got: %v", err)
 	}
 
-	_, err = rw.WriteString("hello world")
+	_, err = rw.WriteString("world")
 	if !errors.Is(err, http.ErrBodyNotAllowed) {
 		t.Errorf("expected BodyNotAllowed for WriteString after 204, got: %v", err)
 	}
+
+	if got, want := rw.Body.String(), "hello world"; got != want {
+		t.Errorf("got Body=%q, want %q", got, want)
+	}
 }
 
 // issue 39017 - disallow Content-Length values such as "+3"

From 27f9a6705c700d9075d4651cf9cff9cabbe4a47e Mon Sep 17 00:00:00 2001
From: Keith Randall 
Date: Wed, 15 Oct 2025 13:28:15 -0700
Subject: [PATCH 160/229] runtime: increase repeat count for alloc test

To make sure a single spurious alloc doesn't flake the test.

Fixes #75858

Change-Id: I055b37ad5668459bfa7ab1dac97025c997c68f1a
Reviewed-on: https://go-review.googlesource.com/c/go/+/712201
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Cherry Mui 
Reviewed-by: Keith Randall 
---
 src/runtime/iface_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/runtime/iface_test.go b/src/runtime/iface_test.go
index 06f6eeb9524637..5bc209cfcf0dc7 100644
--- a/src/runtime/iface_test.go
+++ b/src/runtime/iface_test.go
@@ -60,7 +60,7 @@ func TestCmpIfaceConcreteAlloc(t *testing.T) {
 		t.Skip("skipping on non-gc compiler")
 	}
 
-	n := testing.AllocsPerRun(1, func() {
+	n := testing.AllocsPerRun(100, func() {
 		_ = e == ts
 		_ = i1 == ts
 		_ = e == 1

From 45eee553e29770a264c378bccbb80c44807609f4 Mon Sep 17 00:00:00 2001
From: Vasily Leonenko 
Date: Sat, 6 Sep 2025 23:03:16 +0300
Subject: [PATCH 161/229] cmd/internal/obj: move ARM64RegisterExtension from
 cmd/asm/internal/arch

Change-Id: Iab41674953655efa7be3d306dfb3f5be486be501
Reviewed-on: https://go-review.googlesource.com/c/go/+/701455
Reviewed-by: Cherry Mui 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
---
 src/cmd/asm/internal/arch/arm64.go | 143 ----------------------------
 src/cmd/asm/internal/asm/parse.go  |   2 +-
 src/cmd/internal/obj/arm64/asm7.go | 144 +++++++++++++++++++++++++++++
 3 files changed, 145 insertions(+), 144 deletions(-)

diff --git a/src/cmd/asm/internal/arch/arm64.go b/src/cmd/asm/internal/arch/arm64.go
index 87ccb8c0409313..d562e5907d6fc1 100644
--- a/src/cmd/asm/internal/arch/arm64.go
+++ b/src/cmd/asm/internal/arch/arm64.go
@@ -195,149 +195,6 @@ func ARM64RegisterShift(reg, op, count int16) (int64, error) {
 	return int64(reg&31)<<16 | int64(op)<<22 | int64(uint16(count)), nil
 }
 
-// ARM64RegisterExtension constructs an ARM64 register with extension or arrangement.
-func ARM64RegisterExtension(a *obj.Addr, ext string, reg, num int16, isAmount, isIndex bool) error {
-	Rnum := (reg & 31) + int16(num<<5)
-	if isAmount {
-		if num < 0 || num > 7 {
-			return errors.New("index shift amount is out of range")
-		}
-	}
-	if reg <= arm64.REG_R31 && reg >= arm64.REG_R0 {
-		if !isAmount {
-			return errors.New("invalid register extension")
-		}
-		switch ext {
-		case "UXTB":
-			if a.Type == obj.TYPE_MEM {
-				return errors.New("invalid shift for the register offset addressing mode")
-			}
-			a.Reg = arm64.REG_UXTB + Rnum
-		case "UXTH":
-			if a.Type == obj.TYPE_MEM {
-				return errors.New("invalid shift for the register offset addressing mode")
-			}
-			a.Reg = arm64.REG_UXTH + Rnum
-		case "UXTW":
-			// effective address of memory is a base register value and an offset register value.
-			if a.Type == obj.TYPE_MEM {
-				a.Index = arm64.REG_UXTW + Rnum
-			} else {
-				a.Reg = arm64.REG_UXTW + Rnum
-			}
-		case "UXTX":
-			if a.Type == obj.TYPE_MEM {
-				return errors.New("invalid shift for the register offset addressing mode")
-			}
-			a.Reg = arm64.REG_UXTX + Rnum
-		case "SXTB":
-			if a.Type == obj.TYPE_MEM {
-				return errors.New("invalid shift for the register offset addressing mode")
-			}
-			a.Reg = arm64.REG_SXTB + Rnum
-		case "SXTH":
-			if a.Type == obj.TYPE_MEM {
-				return errors.New("invalid shift for the register offset addressing mode")
-			}
-			a.Reg = arm64.REG_SXTH + Rnum
-		case "SXTW":
-			if a.Type == obj.TYPE_MEM {
-				a.Index = arm64.REG_SXTW + Rnum
-			} else {
-				a.Reg = arm64.REG_SXTW + Rnum
-			}
-		case "SXTX":
-			if a.Type == obj.TYPE_MEM {
-				a.Index = arm64.REG_SXTX + Rnum
-			} else {
-				a.Reg = arm64.REG_SXTX + Rnum
-			}
-		case "LSL":
-			a.Index = arm64.REG_LSL + Rnum
-		default:
-			return errors.New("unsupported general register extension type: " + ext)
-
-		}
-	} else if reg <= arm64.REG_V31 && reg >= arm64.REG_V0 {
-		switch ext {
-		case "B8":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_8B & 15) << 5)
-		case "B16":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_16B & 15) << 5)
-		case "H4":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_4H & 15) << 5)
-		case "H8":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_8H & 15) << 5)
-		case "S2":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_2S & 15) << 5)
-		case "S4":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_4S & 15) << 5)
-		case "D1":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_1D & 15) << 5)
-		case "D2":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_2D & 15) << 5)
-		case "Q1":
-			if isIndex {
-				return errors.New("invalid register extension")
-			}
-			a.Reg = arm64.REG_ARNG + (reg & 31) + ((arm64.ARNG_1Q & 15) << 5)
-		case "B":
-			if !isIndex {
-				return nil
-			}
-			a.Reg = arm64.REG_ELEM + (reg & 31) + ((arm64.ARNG_B & 15) << 5)
-			a.Index = num
-		case "H":
-			if !isIndex {
-				return nil
-			}
-			a.Reg = arm64.REG_ELEM + (reg & 31) + ((arm64.ARNG_H & 15) << 5)
-			a.Index = num
-		case "S":
-			if !isIndex {
-				return nil
-			}
-			a.Reg = arm64.REG_ELEM + (reg & 31) + ((arm64.ARNG_S & 15) << 5)
-			a.Index = num
-		case "D":
-			if !isIndex {
-				return nil
-			}
-			a.Reg = arm64.REG_ELEM + (reg & 31) + ((arm64.ARNG_D & 15) << 5)
-			a.Index = num
-		default:
-			return errors.New("unsupported simd register extension type: " + ext)
-		}
-	} else {
-		return errors.New("invalid register and extension combination")
-	}
-	return nil
-}
-
 // ARM64RegisterArrangement constructs an ARM64 vector register arrangement.
 func ARM64RegisterArrangement(reg int16, name, arng string) (int64, error) {
 	var curQ, curSize uint16
diff --git a/src/cmd/asm/internal/asm/parse.go b/src/cmd/asm/internal/asm/parse.go
index 8f8f6dcc346a44..545f6c7553351b 100644
--- a/src/cmd/asm/internal/asm/parse.go
+++ b/src/cmd/asm/internal/asm/parse.go
@@ -775,7 +775,7 @@ func (p *Parser) registerExtension(a *obj.Addr, name string, prefix rune) {
 
 	switch p.arch.Family {
 	case sys.ARM64:
-		err := arch.ARM64RegisterExtension(a, ext, reg, num, isAmount, isIndex)
+		err := arm64.ARM64RegisterExtension(a, ext, reg, num, isAmount, isIndex)
 		if err != nil {
 			p.errorf("%v", err)
 		}
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index cfb70cf08a3fd8..3cb4be436b9b7f 100644
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -34,6 +34,7 @@ import (
 	"cmd/internal/obj"
 	"cmd/internal/objabi"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"log"
 	"math"
@@ -7855,3 +7856,146 @@ func (c *ctxt7) encRegShiftOrExt(p *obj.Prog, a *obj.Addr, r int16) uint32 {
 func pack(q uint32, arngA, arngB uint8) uint32 {
 	return uint32(q)<<16 | uint32(arngA)<<8 | uint32(arngB)
 }
+
+// ARM64RegisterExtension constructs an ARM64 register with extension or arrangement.
+func ARM64RegisterExtension(a *obj.Addr, ext string, reg, num int16, isAmount, isIndex bool) error {
+	Rnum := (reg & 31) + int16(num<<5)
+	if isAmount {
+		if num < 0 || num > 7 {
+			return errors.New("index shift amount is out of range")
+		}
+	}
+	if reg <= REG_R31 && reg >= REG_R0 {
+		if !isAmount {
+			return errors.New("invalid register extension")
+		}
+		switch ext {
+		case "UXTB":
+			if a.Type == obj.TYPE_MEM {
+				return errors.New("invalid shift for the register offset addressing mode")
+			}
+			a.Reg = REG_UXTB + Rnum
+		case "UXTH":
+			if a.Type == obj.TYPE_MEM {
+				return errors.New("invalid shift for the register offset addressing mode")
+			}
+			a.Reg = REG_UXTH + Rnum
+		case "UXTW":
+			// effective address of memory is a base register value and an offset register value.
+			if a.Type == obj.TYPE_MEM {
+				a.Index = REG_UXTW + Rnum
+			} else {
+				a.Reg = REG_UXTW + Rnum
+			}
+		case "UXTX":
+			if a.Type == obj.TYPE_MEM {
+				return errors.New("invalid shift for the register offset addressing mode")
+			}
+			a.Reg = REG_UXTX + Rnum
+		case "SXTB":
+			if a.Type == obj.TYPE_MEM {
+				return errors.New("invalid shift for the register offset addressing mode")
+			}
+			a.Reg = REG_SXTB + Rnum
+		case "SXTH":
+			if a.Type == obj.TYPE_MEM {
+				return errors.New("invalid shift for the register offset addressing mode")
+			}
+			a.Reg = REG_SXTH + Rnum
+		case "SXTW":
+			if a.Type == obj.TYPE_MEM {
+				a.Index = REG_SXTW + Rnum
+			} else {
+				a.Reg = REG_SXTW + Rnum
+			}
+		case "SXTX":
+			if a.Type == obj.TYPE_MEM {
+				a.Index = REG_SXTX + Rnum
+			} else {
+				a.Reg = REG_SXTX + Rnum
+			}
+		case "LSL":
+			a.Index = REG_LSL + Rnum
+		default:
+			return errors.New("unsupported general register extension type: " + ext)
+
+		}
+	} else if reg <= REG_V31 && reg >= REG_V0 {
+		switch ext {
+		case "B8":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_8B & 15) << 5)
+		case "B16":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_16B & 15) << 5)
+		case "H4":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_4H & 15) << 5)
+		case "H8":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_8H & 15) << 5)
+		case "S2":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_2S & 15) << 5)
+		case "S4":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_4S & 15) << 5)
+		case "D1":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_1D & 15) << 5)
+		case "D2":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_2D & 15) << 5)
+		case "Q1":
+			if isIndex {
+				return errors.New("invalid register extension")
+			}
+			a.Reg = REG_ARNG + (reg & 31) + ((ARNG_1Q & 15) << 5)
+		case "B":
+			if !isIndex {
+				return nil
+			}
+			a.Reg = REG_ELEM + (reg & 31) + ((ARNG_B & 15) << 5)
+			a.Index = num
+		case "H":
+			if !isIndex {
+				return nil
+			}
+			a.Reg = REG_ELEM + (reg & 31) + ((ARNG_H & 15) << 5)
+			a.Index = num
+		case "S":
+			if !isIndex {
+				return nil
+			}
+			a.Reg = REG_ELEM + (reg & 31) + ((ARNG_S & 15) << 5)
+			a.Index = num
+		case "D":
+			if !isIndex {
+				return nil
+			}
+			a.Reg = REG_ELEM + (reg & 31) + ((ARNG_D & 15) << 5)
+			a.Index = num
+		default:
+			return errors.New("unsupported simd register extension type: " + ext)
+		}
+	} else {
+		return errors.New("invalid register and extension combination")
+	}
+	return nil
+}

From 6cbe0920c43a2abe6395bf12256b55abe27f334f Mon Sep 17 00:00:00 2001
From: Alan Donovan 
Date: Fri, 26 Sep 2025 13:03:12 -0400
Subject: [PATCH 162/229] cmd: update to x/tools@7d9453cc

 go get golang.org/x/tools@master
 go mod tidy
 go mod vendor

in both cmd and src, for (enforced) consistency.

Also: GOWORK=off go generate -run=bundle std

This will enable use of modernize and inline.

Change-Id: I6348dd97ec2c41437b3ca899ed91f10815f2fe26
Reviewed-on: https://go-review.googlesource.com/c/go/+/707135
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Alan Donovan 
Reviewed-by: Michael Matloob 
---
 src/cmd/go.mod                                |  10 +-
 src/cmd/go.sum                                |  20 +-
 .../golang.org/x/sys/unix/affinity_linux.go   |   9 +
 src/cmd/vendor/golang.org/x/sys/unix/fdset.go |   4 +-
 .../golang.org/x/sys/unix/ifreq_linux.go      |   4 +-
 src/cmd/vendor/golang.org/x/sys/unix/mkall.sh |   1 +
 .../golang.org/x/sys/unix/syscall_linux.go    |   4 +-
 .../golang.org/x/sys/unix/syscall_netbsd.go   |  17 +
 .../x/sys/windows/syscall_windows.go          |   2 +
 .../golang.org/x/sys/windows/types_windows.go |  16 +
 .../x/sys/windows/zsyscall_windows.go         |  18 +
 .../internal/crashmonitor/monitor.go          |   8 -
 .../analysis/internal/analysisflags/help.go   |  26 +-
 .../go/analysis/passes/appends/appends.go     |   4 +-
 .../go/analysis/passes/asmdecl/asmdecl.go     |   8 +-
 .../tools/go/analysis/passes/assign/assign.go |  39 +-
 .../tools/go/analysis/passes/atomic/atomic.go |  11 +-
 .../x/tools/go/analysis/passes/bools/bools.go |  12 +-
 .../go/analysis/passes/buildtag/buildtag.go   |   4 +-
 .../go/analysis/passes/cgocall/cgocall.go     |   4 +-
 .../go/analysis/passes/copylock/copylock.go   |  15 +-
 .../tools/go/analysis/passes/defers/defers.go |   8 +-
 .../go/analysis/passes/directive/directive.go |   4 +-
 .../go/analysis/passes/errorsas/errorsas.go   |  63 +-
 .../passes/framepointer/framepointer.go       |   6 +-
 .../passes/httpresponse/httpresponse.go       |   9 +-
 .../passes/ifaceassert/ifaceassert.go         |   4 +-
 .../passes/internal/analysisutil/util.go      |  99 ----
 .../passes/loopclosure/loopclosure.go         |   5 +-
 .../analysis/passes/lostcancel/lostcancel.go  |   6 +-
 .../go/analysis/passes/nilfunc/nilfunc.go     |   4 +-
 .../x/tools/go/analysis/passes/printf/doc.go  |  10 +
 .../tools/go/analysis/passes/printf/printf.go | 407 ++++++++-----
 .../x/tools/go/analysis/passes/shift/shift.go |   4 +-
 .../passes/sigchanyzer/sigchanyzer.go         |   6 +-
 .../x/tools/go/analysis/passes/slog/slog.go   |  10 +-
 .../analysis/passes/stdmethods/stdmethods.go  |   4 +-
 .../analysis/passes/stringintconv/string.go   |   6 +-
 .../testinggoroutine/testinggoroutine.go      |   5 +-
 .../x/tools/go/analysis/passes/tests/tests.go |   6 +-
 .../analysis/passes/timeformat/timeformat.go  |  10 +-
 .../go/analysis/passes/unmarshal/unmarshal.go |   6 +-
 .../passes/unreachable/unreachable.go         |  17 +-
 .../go/analysis/passes/unsafeptr/unsafeptr.go |   8 +-
 .../passes/unusedresult/unusedresult.go       |   3 +-
 .../go/analysis/passes/waitgroup/waitgroup.go |   8 +-
 .../go/analysis/unitchecker/unitchecker.go    |  20 +-
 .../internal/analysisinternal/analysis.go     | 540 +-----------------
 .../internal/analysisinternal/extractdoc.go   |   2 +-
 .../x/tools/internal/astutil/comment.go       |  22 +
 .../x/tools/internal/astutil/equal.go         |   8 +
 .../x/tools/internal/astutil/util.go          |  50 ++
 .../x/tools/internal/diff/lcs/old.go          |   5 +-
 .../x/tools/internal/diff/lcs/sequence.go     |   8 -
 .../tools/internal/packagepath/packagepath.go |  49 ++
 .../x/tools/internal/refactor/delete.go       | 484 ++++++++++++++++
 .../x/tools/internal/refactor/imports.go      | 127 ++++
 .../x/tools/internal/refactor/refactor.go     |  29 +
 .../x/tools/internal/typesinternal/fx.go      |  88 +++
 .../x/tools/internal/typesinternal/isnamed.go |  71 +++
 .../x/tools/internal/typesinternal/types.go   |  48 +-
 .../x/tools/internal/typesinternal/varkind.go |  39 +-
 .../internal/typesinternal/varkind_go124.go   |  39 ++
 .../tools/internal/typesinternal/zerovalue.go |  17 +-
 src/cmd/vendor/modules.txt                    |  13 +-
 src/go.mod                                    |   8 +-
 src/go.sum                                    |  16 +-
 src/net/http/h2_bundle.go                     |   6 +
 .../golang.org/x/text/unicode/bidi/core.go    |  11 +-
 src/vendor/modules.txt                        |   8 +-
 70 files changed, 1596 insertions(+), 1066 deletions(-)
 delete mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/internal/analysisutil/util.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/packagepath/packagepath.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/delete.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/imports.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/refactor.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/typesinternal/fx.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/typesinternal/isnamed.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/typesinternal/varkind_go124.go

diff --git a/src/cmd/go.mod b/src/cmd/go.mod
index 017883a7870cd2..1fc256ae6f2ce7 100644
--- a/src/cmd/go.mod
+++ b/src/cmd/go.mod
@@ -6,16 +6,16 @@ require (
 	github.com/google/pprof v0.0.0-20250630185457-6e76a2b096b5
 	golang.org/x/arch v0.20.1-0.20250808194827-46ba08e3ae58
 	golang.org/x/build v0.0.0-20250806225920-b7c66c047964
-	golang.org/x/mod v0.28.0
+	golang.org/x/mod v0.29.0
 	golang.org/x/sync v0.17.0
-	golang.org/x/sys v0.36.0
-	golang.org/x/telemetry v0.0.0-20250908211612-aef8a434d053
+	golang.org/x/sys v0.37.0
+	golang.org/x/telemetry v0.0.0-20251008203120-078029d740a8
 	golang.org/x/term v0.34.0
-	golang.org/x/tools v0.37.1-0.20250924232827-4df13e317ce4
+	golang.org/x/tools v0.38.1-0.20251015192825-7d9453ccc0f5
 )
 
 require (
 	github.com/ianlancetaylor/demangle v0.0.0-20250417193237-f615e6bd150b // indirect
-	golang.org/x/text v0.29.0 // indirect
+	golang.org/x/text v0.30.0 // indirect
 	rsc.io/markdown v0.0.0-20240306144322-0bf8f97ee8ef // indirect
 )
diff --git a/src/cmd/go.sum b/src/cmd/go.sum
index 0906ffcc605854..eb7af161552020 100644
--- a/src/cmd/go.sum
+++ b/src/cmd/go.sum
@@ -10,19 +10,19 @@ golang.org/x/arch v0.20.1-0.20250808194827-46ba08e3ae58 h1:uxPa6+/WsUfzikIAPMqpT
 golang.org/x/arch v0.20.1-0.20250808194827-46ba08e3ae58/go.mod h1:bdwinDaKcfZUGpH09BB7ZmOfhalA8lQdzl62l8gGWsk=
 golang.org/x/build v0.0.0-20250806225920-b7c66c047964 h1:yRs1K51GKq7hsIO+YHJ8LsslrvwFceNPIv0tYjpcBd0=
 golang.org/x/build v0.0.0-20250806225920-b7c66c047964/go.mod h1:i9Vx7+aOQUpYJRxSO+OpRStVBCVL/9ccI51xblWm5WY=
-golang.org/x/mod v0.28.0 h1:gQBtGhjxykdjY9YhZpSlZIsbnaE2+PgjfLWUQTnoZ1U=
-golang.org/x/mod v0.28.0/go.mod h1:yfB/L0NOf/kmEbXjzCPOx1iK1fRutOydrCMsqRhEBxI=
+golang.org/x/mod v0.29.0 h1:HV8lRxZC4l2cr3Zq1LvtOsi/ThTgWnUk/y64QSs8GwA=
+golang.org/x/mod v0.29.0/go.mod h1:NyhrlYXJ2H4eJiRy/WDBO6HMqZQ6q9nk4JzS3NuCK+w=
 golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
 golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
-golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
-golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
-golang.org/x/telemetry v0.0.0-20250908211612-aef8a434d053 h1:dHQOQddU4YHS5gY33/6klKjq7Gp3WwMyOXGNp5nzRj8=
-golang.org/x/telemetry v0.0.0-20250908211612-aef8a434d053/go.mod h1:+nZKN+XVh4LCiA9DV3ywrzN4gumyCnKjau3NGb9SGoE=
+golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
+golang.org/x/sys v0.37.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/telemetry v0.0.0-20251008203120-078029d740a8 h1:LvzTn0GQhWuvKH/kVRS3R3bVAsdQWI7hvfLHGgh9+lU=
+golang.org/x/telemetry v0.0.0-20251008203120-078029d740a8/go.mod h1:Pi4ztBfryZoJEkyFTI5/Ocsu2jXyDr6iSdgJiYE/uwE=
 golang.org/x/term v0.34.0 h1:O/2T7POpk0ZZ7MAzMeWFSg6S5IpWd/RXDlM9hgM3DR4=
 golang.org/x/term v0.34.0/go.mod h1:5jC53AEywhIVebHgPVeg0mj8OD3VO9OzclacVrqpaAw=
-golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
-golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=
-golang.org/x/tools v0.37.1-0.20250924232827-4df13e317ce4 h1:IcXDtHggZZo+GzNzvVRPyNFLnOc2/Z1gg3ZVIWF2uCU=
-golang.org/x/tools v0.37.1-0.20250924232827-4df13e317ce4/go.mod h1:MBN5QPQtLMHVdvsbtarmTNukZDdgwdwlO5qGacAzF0w=
+golang.org/x/text v0.30.0 h1:yznKA/E9zq54KzlzBEAWn1NXSQ8DIp/NYMy88xJjl4k=
+golang.org/x/text v0.30.0/go.mod h1:yDdHFIX9t+tORqspjENWgzaCVXgk0yYnYuSZ8UzzBVM=
+golang.org/x/tools v0.38.1-0.20251015192825-7d9453ccc0f5 h1:cz7f45KGWAtyIrz6bm45Gc+lw8beIxBSW3EQh4Bwbg4=
+golang.org/x/tools v0.38.1-0.20251015192825-7d9453ccc0f5/go.mod h1:yEsQ/d/YK8cjh0L6rZlY8tgtlKiBNTL14pGDJPJpYQs=
 rsc.io/markdown v0.0.0-20240306144322-0bf8f97ee8ef h1:mqLYrXCXYEZOop9/Dbo6RPX11539nwiCNBb1icVPmw8=
 rsc.io/markdown v0.0.0-20240306144322-0bf8f97ee8ef/go.mod h1:8xcPgWmwlZONN1D9bjxtHEjrUtSEa3fakVF8iaewYKQ=
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/affinity_linux.go b/src/cmd/vendor/golang.org/x/sys/unix/affinity_linux.go
index 3c7a6d6e2f1d2f..3ea470387bcf08 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/affinity_linux.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/affinity_linux.go
@@ -41,6 +41,15 @@ func (s *CPUSet) Zero() {
 	clear(s[:])
 }
 
+// Fill adds all possible CPU bits to the set s. On Linux, [SchedSetaffinity]
+// will silently ignore any invalid CPU bits in [CPUSet] so this is an
+// efficient way of resetting the CPU affinity of a process.
+func (s *CPUSet) Fill() {
+	for i := range s {
+		s[i] = ^cpuMask(0)
+	}
+}
+
 func cpuBitsIndex(cpu int) int {
 	return cpu / _NCPUBITS
 }
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/fdset.go b/src/cmd/vendor/golang.org/x/sys/unix/fdset.go
index 9e83d18cd04215..62ed12645f48dd 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/fdset.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/fdset.go
@@ -23,7 +23,5 @@ func (fds *FdSet) IsSet(fd int) bool {
 
 // Zero clears the set fds.
 func (fds *FdSet) Zero() {
-	for i := range fds.Bits {
-		fds.Bits[i] = 0
-	}
+	clear(fds.Bits[:])
 }
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/ifreq_linux.go b/src/cmd/vendor/golang.org/x/sys/unix/ifreq_linux.go
index 848840ae4c7586..309f5a2b0c76ae 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/ifreq_linux.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/ifreq_linux.go
@@ -111,9 +111,7 @@ func (ifr *Ifreq) SetUint32(v uint32) {
 // clear zeroes the ifreq's union field to prevent trailing garbage data from
 // being sent to the kernel if an ifreq is reused.
 func (ifr *Ifreq) clear() {
-	for i := range ifr.raw.Ifru {
-		ifr.raw.Ifru[i] = 0
-	}
+	clear(ifr.raw.Ifru[:])
 }
 
 // TODO(mdlayher): export as IfreqData? For now we can provide helpers such as
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/mkall.sh b/src/cmd/vendor/golang.org/x/sys/unix/mkall.sh
index e6f31d374df52c..d0ed6119129296 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/mkall.sh
+++ b/src/cmd/vendor/golang.org/x/sys/unix/mkall.sh
@@ -49,6 +49,7 @@ esac
 if [[ "$GOOS" = "linux" ]]; then
 	# Use the Docker-based build system
 	# Files generated through docker (use $cmd so you can Ctl-C the build or run)
+	set -e
 	$cmd docker build --tag generate:$GOOS $GOOS
 	$cmd docker run --interactive --tty --volume $(cd -- "$(dirname -- "$0")/.." && pwd):/build generate:$GOOS
 	exit
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux.go b/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux.go
index 4958a657085bcd..9439af961d98b6 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/syscall_linux.go
@@ -801,9 +801,7 @@ func (sa *SockaddrPPPoE) sockaddr() (unsafe.Pointer, _Socklen, error) {
 	// one. The kernel expects SID to be in network byte order.
 	binary.BigEndian.PutUint16(sa.raw[6:8], sa.SID)
 	copy(sa.raw[8:14], sa.Remote)
-	for i := 14; i < 14+IFNAMSIZ; i++ {
-		sa.raw[i] = 0
-	}
+	clear(sa.raw[14 : 14+IFNAMSIZ])
 	copy(sa.raw[14:], sa.Dev)
 	return unsafe.Pointer(&sa.raw), SizeofSockaddrPPPoX, nil
 }
diff --git a/src/cmd/vendor/golang.org/x/sys/unix/syscall_netbsd.go b/src/cmd/vendor/golang.org/x/sys/unix/syscall_netbsd.go
index 88162099af5444..34a4676973042f 100644
--- a/src/cmd/vendor/golang.org/x/sys/unix/syscall_netbsd.go
+++ b/src/cmd/vendor/golang.org/x/sys/unix/syscall_netbsd.go
@@ -248,6 +248,23 @@ func Statvfs(path string, buf *Statvfs_t) (err error) {
 	return Statvfs1(path, buf, ST_WAIT)
 }
 
+func Getvfsstat(buf []Statvfs_t, flags int) (n int, err error) {
+	var (
+		_p0     unsafe.Pointer
+		bufsize uintptr
+	)
+	if len(buf) > 0 {
+		_p0 = unsafe.Pointer(&buf[0])
+		bufsize = unsafe.Sizeof(Statvfs_t{}) * uintptr(len(buf))
+	}
+	r0, _, e1 := Syscall(SYS_GETVFSSTAT, uintptr(_p0), bufsize, uintptr(flags))
+	n = int(r0)
+	if e1 != 0 {
+		err = e1
+	}
+	return
+}
+
 /*
  * Exposed directly
  */
diff --git a/src/cmd/vendor/golang.org/x/sys/windows/syscall_windows.go b/src/cmd/vendor/golang.org/x/sys/windows/syscall_windows.go
index 640f6b153f0045..bd51337306019a 100644
--- a/src/cmd/vendor/golang.org/x/sys/windows/syscall_windows.go
+++ b/src/cmd/vendor/golang.org/x/sys/windows/syscall_windows.go
@@ -321,6 +321,8 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	SetConsoleOutputCP(cp uint32) (err error) = kernel32.SetConsoleOutputCP
 //sys	WriteConsole(console Handle, buf *uint16, towrite uint32, written *uint32, reserved *byte) (err error) = kernel32.WriteConsoleW
 //sys	ReadConsole(console Handle, buf *uint16, toread uint32, read *uint32, inputControl *byte) (err error) = kernel32.ReadConsoleW
+//sys	GetNumberOfConsoleInputEvents(console Handle, numevents *uint32) (err error) = kernel32.GetNumberOfConsoleInputEvents
+//sys	FlushConsoleInputBuffer(console Handle) (err error) = kernel32.FlushConsoleInputBuffer
 //sys	resizePseudoConsole(pconsole Handle, size uint32) (hr error) = kernel32.ResizePseudoConsole
 //sys	CreateToolhelp32Snapshot(flags uint32, processId uint32) (handle Handle, err error) [failretval==InvalidHandle] = kernel32.CreateToolhelp32Snapshot
 //sys	Module32First(snapshot Handle, moduleEntry *ModuleEntry32) (err error) = kernel32.Module32FirstW
diff --git a/src/cmd/vendor/golang.org/x/sys/windows/types_windows.go b/src/cmd/vendor/golang.org/x/sys/windows/types_windows.go
index 993a2297dbe1a5..358be3c7f5eece 100644
--- a/src/cmd/vendor/golang.org/x/sys/windows/types_windows.go
+++ b/src/cmd/vendor/golang.org/x/sys/windows/types_windows.go
@@ -65,6 +65,22 @@ var signals = [...]string{
 	15: "terminated",
 }
 
+// File flags for [os.OpenFile]. The O_ prefix is used to indicate
+// that these flags are specific to the OpenFile function.
+const (
+	O_FILE_FLAG_OPEN_NO_RECALL     = FILE_FLAG_OPEN_NO_RECALL
+	O_FILE_FLAG_OPEN_REPARSE_POINT = FILE_FLAG_OPEN_REPARSE_POINT
+	O_FILE_FLAG_SESSION_AWARE      = FILE_FLAG_SESSION_AWARE
+	O_FILE_FLAG_POSIX_SEMANTICS    = FILE_FLAG_POSIX_SEMANTICS
+	O_FILE_FLAG_BACKUP_SEMANTICS   = FILE_FLAG_BACKUP_SEMANTICS
+	O_FILE_FLAG_DELETE_ON_CLOSE    = FILE_FLAG_DELETE_ON_CLOSE
+	O_FILE_FLAG_SEQUENTIAL_SCAN    = FILE_FLAG_SEQUENTIAL_SCAN
+	O_FILE_FLAG_RANDOM_ACCESS      = FILE_FLAG_RANDOM_ACCESS
+	O_FILE_FLAG_NO_BUFFERING       = FILE_FLAG_NO_BUFFERING
+	O_FILE_FLAG_OVERLAPPED         = FILE_FLAG_OVERLAPPED
+	O_FILE_FLAG_WRITE_THROUGH      = FILE_FLAG_WRITE_THROUGH
+)
+
 const (
 	FILE_READ_DATA        = 0x00000001
 	FILE_READ_ATTRIBUTES  = 0x00000080
diff --git a/src/cmd/vendor/golang.org/x/sys/windows/zsyscall_windows.go b/src/cmd/vendor/golang.org/x/sys/windows/zsyscall_windows.go
index 641a5f4b775aa1..426151a0193d35 100644
--- a/src/cmd/vendor/golang.org/x/sys/windows/zsyscall_windows.go
+++ b/src/cmd/vendor/golang.org/x/sys/windows/zsyscall_windows.go
@@ -238,6 +238,7 @@ var (
 	procFindResourceW                                        = modkernel32.NewProc("FindResourceW")
 	procFindVolumeClose                                      = modkernel32.NewProc("FindVolumeClose")
 	procFindVolumeMountPointClose                            = modkernel32.NewProc("FindVolumeMountPointClose")
+	procFlushConsoleInputBuffer                              = modkernel32.NewProc("FlushConsoleInputBuffer")
 	procFlushFileBuffers                                     = modkernel32.NewProc("FlushFileBuffers")
 	procFlushViewOfFile                                      = modkernel32.NewProc("FlushViewOfFile")
 	procFormatMessageW                                       = modkernel32.NewProc("FormatMessageW")
@@ -284,6 +285,7 @@ var (
 	procGetNamedPipeHandleStateW                             = modkernel32.NewProc("GetNamedPipeHandleStateW")
 	procGetNamedPipeInfo                                     = modkernel32.NewProc("GetNamedPipeInfo")
 	procGetNamedPipeServerProcessId                          = modkernel32.NewProc("GetNamedPipeServerProcessId")
+	procGetNumberOfConsoleInputEvents                        = modkernel32.NewProc("GetNumberOfConsoleInputEvents")
 	procGetOverlappedResult                                  = modkernel32.NewProc("GetOverlappedResult")
 	procGetPriorityClass                                     = modkernel32.NewProc("GetPriorityClass")
 	procGetProcAddress                                       = modkernel32.NewProc("GetProcAddress")
@@ -2111,6 +2113,14 @@ func FindVolumeMountPointClose(findVolumeMountPoint Handle) (err error) {
 	return
 }
 
+func FlushConsoleInputBuffer(console Handle) (err error) {
+	r1, _, e1 := syscall.SyscallN(procFlushConsoleInputBuffer.Addr(), uintptr(console))
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func FlushFileBuffers(handle Handle) (err error) {
 	r1, _, e1 := syscall.SyscallN(procFlushFileBuffers.Addr(), uintptr(handle))
 	if r1 == 0 {
@@ -2481,6 +2491,14 @@ func GetNamedPipeServerProcessId(pipe Handle, serverProcessID *uint32) (err erro
 	return
 }
 
+func GetNumberOfConsoleInputEvents(console Handle, numevents *uint32) (err error) {
+	r1, _, e1 := syscall.SyscallN(procGetNumberOfConsoleInputEvents.Addr(), uintptr(console), uintptr(unsafe.Pointer(numevents)))
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func GetOverlappedResult(handle Handle, overlapped *Overlapped, done *uint32, wait bool) (err error) {
 	var _p0 uint32
 	if wait {
diff --git a/src/cmd/vendor/golang.org/x/telemetry/internal/crashmonitor/monitor.go b/src/cmd/vendor/golang.org/x/telemetry/internal/crashmonitor/monitor.go
index 53966ad2bcb362..ac22f68c34ccf1 100644
--- a/src/cmd/vendor/golang.org/x/telemetry/internal/crashmonitor/monitor.go
+++ b/src/cmd/vendor/golang.org/x/telemetry/internal/crashmonitor/monitor.go
@@ -326,11 +326,3 @@ func parseStackPCs(crash string) ([]uintptr, error) {
 	}
 	return pcs, nil
 }
-
-func min(x, y int) int {
-	if x < y {
-		return x
-	} else {
-		return y
-	}
-}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/help.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/help.go
index ce92892c817690..0ca27316e6236b 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/help.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/internal/analysisflags/help.go
@@ -17,10 +17,26 @@ import (
 
 const help = `PROGNAME is a tool for static analysis of Go programs.
 
-PROGNAME examines Go source code and reports suspicious constructs,
-such as Printf calls whose arguments do not align with the format
-string. It uses heuristics that do not guarantee all reports are
-genuine problems, but it can find errors not caught by the compilers.
+PROGNAME examines Go source code and reports diagnostics for
+suspicious constructs or opportunities for improvement.
+Diagnostics may include suggested fixes.
+
+An example of a suspicious construct is a Printf call whose arguments
+do not align with the format string. Analyzers may use heuristics that
+do not guarantee all reports are genuine problems, but can find
+mistakes not caught by the compiler.
+
+An example of an opportunity for improvement is a loop over
+strings.Split(doc, "\n"), which may be replaced by a loop over the
+strings.SplitSeq iterator, avoiding an array allocation.
+Diagnostics in such cases may report non-problems,
+but should carry fixes that may be safely applied.
+
+For analyzers of the first kind, use "go vet -vettool=PROGRAM"
+to run the tool and report diagnostics.
+
+For analyzers of the second kind, use "go fix -fixtool=PROGRAM"
+to run the tool and apply the fixes it suggests.
 `
 
 // Help implements the help subcommand for a multichecker or unitchecker
@@ -29,7 +45,7 @@ genuine problems, but it can find errors not caught by the compilers.
 func Help(progname string, analyzers []*analysis.Analyzer, args []string) {
 	// No args: show summary of all analyzers.
 	if len(args) == 0 {
-		fmt.Println(strings.Replace(help, "PROGNAME", progname, -1))
+		fmt.Println(strings.ReplaceAll(help, "PROGNAME", progname))
 		fmt.Println("Registered analyzers:")
 		fmt.Println()
 		sort.Slice(analyzers, func(i, j int) bool {
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/appends/appends.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/appends/appends.go
index e554c3cc90301e..b4e91edce3b88a 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/appends/appends.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/appends/appends.go
@@ -13,9 +13,9 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
 )
 
 //go:embed doc.go
@@ -23,7 +23,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "appends",
-	Doc:      analysisutil.MustExtractDoc(doc, "appends"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "appends"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/appends",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/asmdecl/asmdecl.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/asmdecl/asmdecl.go
index efbf05d596a6d2..e9c08798449386 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/asmdecl/asmdecl.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/asmdecl/asmdecl.go
@@ -19,7 +19,7 @@ import (
 	"strings"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+	"golang.org/x/tools/internal/analysisinternal"
 )
 
 const Doc = "report mismatches between assembly files and Go declarations"
@@ -175,7 +175,7 @@ func run(pass *analysis.Pass) (any, error) {
 
 Files:
 	for _, fname := range sfiles {
-		content, tf, err := analysisutil.ReadFile(pass, fname)
+		content, tf, err := analysisinternal.ReadFile(pass, fname)
 		if err != nil {
 			return nil, err
 		}
@@ -211,7 +211,7 @@ Files:
 					resultStr = "result register"
 				}
 				for _, line := range retLine {
-					pass.Reportf(analysisutil.LineStart(tf, line), "[%s] %s: RET without writing to %s", arch, fnName, resultStr)
+					pass.Reportf(tf.LineStart(line), "[%s] %s: RET without writing to %s", arch, fnName, resultStr)
 				}
 			}
 			retLine = nil
@@ -227,7 +227,7 @@ Files:
 			lineno++
 
 			badf := func(format string, args ...any) {
-				pass.Reportf(analysisutil.LineStart(tf, lineno), "[%s] %s: %s", arch, fnName, fmt.Sprintf(format, args...))
+				pass.Reportf(tf.LineStart(lineno), "[%s] %s: %s", arch, fnName, fmt.Sprintf(format, args...))
 			}
 
 			if arch == "" {
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/assign/assign.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/assign/assign.go
index 1914bb476168ba..8080aed020e5f9 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/assign/assign.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/assign/assign.go
@@ -17,9 +17,11 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 //go:embed doc.go
@@ -27,26 +29,26 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "assign",
-	Doc:      analysisutil.MustExtractDoc(doc, "assign"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "assign"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/assign",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
 }
 
 func run(pass *analysis.Pass) (any, error) {
-	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	var (
+		inspect = pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		info    = pass.TypesInfo
+	)
 
-	nodeFilter := []ast.Node{
-		(*ast.AssignStmt)(nil),
-	}
-	inspect.Preorder(nodeFilter, func(n ast.Node) {
-		stmt := n.(*ast.AssignStmt)
+	for curAssign := range inspect.Root().Preorder((*ast.AssignStmt)(nil)) {
+		stmt := curAssign.Node().(*ast.AssignStmt)
 		if stmt.Tok != token.ASSIGN {
-			return // ignore :=
+			continue // ignore :=
 		}
 		if len(stmt.Lhs) != len(stmt.Rhs) {
 			// If LHS and RHS have different cardinality, they can't be the same.
-			return
+			continue
 		}
 
 		// Delete redundant LHS, RHS pairs, taking care
@@ -61,13 +63,13 @@ func run(pass *analysis.Pass) (any, error) {
 			isSelfAssign := false
 			var le string
 
-			if !analysisutil.HasSideEffects(pass.TypesInfo, lhs) &&
-				!analysisutil.HasSideEffects(pass.TypesInfo, rhs) &&
-				!isMapIndex(pass.TypesInfo, lhs) &&
+			if typesinternal.NoEffects(info, lhs) &&
+				typesinternal.NoEffects(info, rhs) &&
+				!isMapIndex(info, lhs) &&
 				reflect.TypeOf(lhs) == reflect.TypeOf(rhs) { // short-circuit the heavy-weight gofmt check
 
-				le = analysisinternal.Format(pass.Fset, lhs)
-				re := analysisinternal.Format(pass.Fset, rhs)
+				le = astutil.Format(pass.Fset, lhs)
+				re := astutil.Format(pass.Fset, rhs)
 				if le == re {
 					isSelfAssign = true
 				}
@@ -109,13 +111,14 @@ func run(pass *analysis.Pass) (any, error) {
 		}
 
 		if len(exprs) == 0 {
-			return
+			continue
 		}
 
 		if len(exprs) == len(stmt.Lhs) {
 			// If every part of the statement is a self-assignment,
 			// remove the whole statement.
-			edits = []analysis.TextEdit{{Pos: stmt.Pos(), End: stmt.End()}}
+			tokFile := pass.Fset.File(stmt.Pos())
+			edits = refactor.DeleteStmt(tokFile, curAssign)
 		}
 
 		pass.Report(analysis.Diagnostic{
@@ -126,7 +129,7 @@ func run(pass *analysis.Pass) (any, error) {
 				TextEdits: edits,
 			}},
 		})
-	})
+	}
 
 	return nil, nil
 }
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/atomic/atomic.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/atomic/atomic.go
index 82d5439ce571e9..9faa3f67c1deae 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/atomic/atomic.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/atomic/atomic.go
@@ -11,10 +11,11 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 //go:embed doc.go
@@ -22,7 +23,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:             "atomic",
-	Doc:              analysisutil.MustExtractDoc(doc, "atomic"),
+	Doc:              analysisinternal.MustExtractDoc(doc, "atomic"),
 	URL:              "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/atomic",
 	Requires:         []*analysis.Analyzer{inspect.Analyzer},
 	RunDespiteErrors: true,
@@ -30,7 +31,7 @@ var Analyzer = &analysis.Analyzer{
 }
 
 func run(pass *analysis.Pass) (any, error) {
-	if !analysisinternal.Imports(pass.Pkg, "sync/atomic") {
+	if !typesinternal.Imports(pass.Pkg, "sync/atomic") {
 		return nil, nil // doesn't directly import sync/atomic
 	}
 
@@ -54,7 +55,7 @@ func run(pass *analysis.Pass) (any, error) {
 				continue
 			}
 			obj := typeutil.Callee(pass.TypesInfo, call)
-			if analysisinternal.IsFunctionNamed(obj, "sync/atomic", "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr") {
+			if typesinternal.IsFunctionNamed(obj, "sync/atomic", "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr") {
 				checkAtomicAddAssignment(pass, n.Lhs[i], call)
 			}
 		}
@@ -72,7 +73,7 @@ func checkAtomicAddAssignment(pass *analysis.Pass, left ast.Expr, call *ast.Call
 	arg := call.Args[0]
 	broken := false
 
-	gofmt := func(e ast.Expr) string { return analysisinternal.Format(pass.Fset, e) }
+	gofmt := func(e ast.Expr) string { return astutil.Format(pass.Fset, e) }
 
 	if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
 		broken = gofmt(left) == gofmt(uarg.X)
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/bools/bools.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/bools/bools.go
index e1cf9f9b7ade10..574fafaa95dc98 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/bools/bools.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/bools/bools.go
@@ -13,9 +13,9 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 const Doc = "check for common mistakes involving boolean operators"
@@ -84,7 +84,7 @@ func (op boolOp) commutativeSets(info *types.Info, e *ast.BinaryExpr, seen map[*
 	i := 0
 	var sets [][]ast.Expr
 	for j := 0; j <= len(exprs); j++ {
-		if j == len(exprs) || analysisutil.HasSideEffects(info, exprs[j]) {
+		if j == len(exprs) || !typesinternal.NoEffects(info, exprs[j]) {
 			if i < j {
 				sets = append(sets, exprs[i:j])
 			}
@@ -104,7 +104,7 @@ func (op boolOp) commutativeSets(info *types.Info, e *ast.BinaryExpr, seen map[*
 func (op boolOp) checkRedundant(pass *analysis.Pass, exprs []ast.Expr) {
 	seen := make(map[string]bool)
 	for _, e := range exprs {
-		efmt := analysisinternal.Format(pass.Fset, e)
+		efmt := astutil.Format(pass.Fset, e)
 		if seen[efmt] {
 			pass.ReportRangef(e, "redundant %s: %s %s %s", op.name, efmt, op.tok, efmt)
 		} else {
@@ -150,8 +150,8 @@ func (op boolOp) checkSuspect(pass *analysis.Pass, exprs []ast.Expr) {
 		}
 
 		// e is of the form 'x != c' or 'x == c'.
-		xfmt := analysisinternal.Format(pass.Fset, x)
-		efmt := analysisinternal.Format(pass.Fset, e)
+		xfmt := astutil.Format(pass.Fset, x)
+		efmt := astutil.Format(pass.Fset, e)
 		if prev, found := seen[xfmt]; found {
 			// checkRedundant handles the case in which efmt == prev.
 			if efmt != prev {
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/buildtag/buildtag.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/buildtag/buildtag.go
index 6e32f298dc25e3..7dd4f249e258cf 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/buildtag/buildtag.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/buildtag/buildtag.go
@@ -14,7 +14,7 @@ import (
 	"unicode"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+	"golang.org/x/tools/internal/analysisinternal"
 )
 
 const Doc = "check //go:build and // +build directives"
@@ -86,7 +86,7 @@ func checkOtherFile(pass *analysis.Pass, filename string) error {
 
 	// We cannot use the Go parser, since this may not be a Go source file.
 	// Read the raw bytes instead.
-	content, tf, err := analysisutil.ReadFile(pass, filename)
+	content, tf, err := analysisinternal.ReadFile(pass, filename)
 	if err != nil {
 		return err
 	}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/cgocall/cgocall.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/cgocall/cgocall.go
index d9189b5b69608f..bf1202b92b73d4 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/cgocall/cgocall.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/cgocall/cgocall.go
@@ -18,7 +18,7 @@ import (
 	"strconv"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 const debug = false
@@ -41,7 +41,7 @@ var Analyzer = &analysis.Analyzer{
 }
 
 func run(pass *analysis.Pass) (any, error) {
-	if !analysisinternal.Imports(pass.Pkg, "runtime/cgo") {
+	if !typesinternal.Imports(pass.Pkg, "runtime/cgo") {
 		return nil, nil // doesn't use cgo
 	}
 
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/copylock/copylock.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/copylock/copylock.go
index d35b85f03a721b..4190cc5900f682 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/copylock/copylock.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/copylock/copylock.go
@@ -16,8 +16,9 @@ import (
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
 	"golang.org/x/tools/internal/typeparams"
+	"golang.org/x/tools/internal/typesinternal"
 	"golang.org/x/tools/internal/versions"
 )
 
@@ -86,7 +87,7 @@ func checkCopyLocksAssign(pass *analysis.Pass, assign *ast.AssignStmt, goversion
 	lhs := assign.Lhs
 	for i, x := range assign.Rhs {
 		if path := lockPathRhs(pass, x); path != nil {
-			pass.ReportRangef(x, "assignment copies lock value to %v: %v", analysisinternal.Format(pass.Fset, assign.Lhs[i]), path)
+			pass.ReportRangef(x, "assignment copies lock value to %v: %v", astutil.Format(pass.Fset, assign.Lhs[i]), path)
 			lhs = nil // An lhs has been reported. We prefer the assignment warning and do not report twice.
 		}
 	}
@@ -100,7 +101,7 @@ func checkCopyLocksAssign(pass *analysis.Pass, assign *ast.AssignStmt, goversion
 				if id, ok := l.(*ast.Ident); ok && id.Name != "_" {
 					if obj := pass.TypesInfo.Defs[id]; obj != nil && obj.Type() != nil {
 						if path := lockPath(pass.Pkg, obj.Type(), nil); path != nil {
-							pass.ReportRangef(l, "for loop iteration copies lock value to %v: %v", analysisinternal.Format(pass.Fset, l), path)
+							pass.ReportRangef(l, "for loop iteration copies lock value to %v: %v", astutil.Format(pass.Fset, l), path)
 						}
 					}
 				}
@@ -132,7 +133,7 @@ func checkCopyLocksCompositeLit(pass *analysis.Pass, cl *ast.CompositeLit) {
 			x = node.Value
 		}
 		if path := lockPathRhs(pass, x); path != nil {
-			pass.ReportRangef(x, "literal copies lock value from %v: %v", analysisinternal.Format(pass.Fset, x), path)
+			pass.ReportRangef(x, "literal copies lock value from %v: %v", astutil.Format(pass.Fset, x), path)
 		}
 	}
 }
@@ -166,7 +167,7 @@ func checkCopyLocksCallExpr(pass *analysis.Pass, ce *ast.CallExpr) {
 	}
 	for _, x := range ce.Args {
 		if path := lockPathRhs(pass, x); path != nil {
-			pass.ReportRangef(x, "call of %s copies lock value: %v", analysisinternal.Format(pass.Fset, ce.Fun), path)
+			pass.ReportRangef(x, "call of %s copies lock value: %v", astutil.Format(pass.Fset, ce.Fun), path)
 		}
 	}
 }
@@ -233,7 +234,7 @@ func checkCopyLocksRangeVar(pass *analysis.Pass, rtok token.Token, e ast.Expr) {
 		return
 	}
 	if path := lockPath(pass.Pkg, typ, nil); path != nil {
-		pass.Reportf(e.Pos(), "range var %s copies lock: %v", analysisinternal.Format(pass.Fset, e), path)
+		pass.Reportf(e.Pos(), "range var %s copies lock: %v", astutil.Format(pass.Fset, e), path)
 	}
 }
 
@@ -353,7 +354,7 @@ func lockPath(tpkg *types.Package, typ types.Type, seen map[types.Type]bool) typ
 	// In go1.10, sync.noCopy did not implement Locker.
 	// (The Unlock method was added only in CL 121876.)
 	// TODO(adonovan): remove workaround when we drop go1.10.
-	if analysisinternal.IsTypeNamed(typ, "sync", "noCopy") {
+	if typesinternal.IsTypeNamed(typ, "sync", "noCopy") {
 		return []string{typ.String()}
 	}
 
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/defers.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/defers.go
index e11957f2d099d1..3069ee9fecd847 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/defers.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/defers.go
@@ -10,10 +10,10 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 //go:embed doc.go
@@ -23,20 +23,20 @@ var doc string
 var Analyzer = &analysis.Analyzer{
 	Name:     "defers",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
+	Doc:      analysisinternal.MustExtractDoc(doc, "defers"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/defers",
-	Doc:      analysisutil.MustExtractDoc(doc, "defers"),
 	Run:      run,
 }
 
 func run(pass *analysis.Pass) (any, error) {
-	if !analysisinternal.Imports(pass.Pkg, "time") {
+	if !typesinternal.Imports(pass.Pkg, "time") {
 		return nil, nil
 	}
 
 	checkDeferCall := func(node ast.Node) bool {
 		switch v := node.(type) {
 		case *ast.CallExpr:
-			if analysisinternal.IsFunctionNamed(typeutil.Callee(pass.TypesInfo, v), "time", "Since") {
+			if typesinternal.IsFunctionNamed(typeutil.Callee(pass.TypesInfo, v), "time", "Since") {
 				pass.Reportf(v.Pos(), "call to time.Since is not deferred")
 			}
 		case *ast.FuncLit:
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/directive/directive.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/directive/directive.go
index bebec891408fef..c84d25842e3018 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/directive/directive.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/directive/directive.go
@@ -14,7 +14,7 @@ import (
 	"unicode/utf8"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+	"golang.org/x/tools/internal/analysisinternal"
 )
 
 const Doc = `check Go toolchain directives such as //go:debug
@@ -86,7 +86,7 @@ func checkGoFile(pass *analysis.Pass, f *ast.File) {
 func checkOtherFile(pass *analysis.Pass, filename string) error {
 	// We cannot use the Go parser, since is not a Go source file.
 	// Read the raw bytes instead.
-	content, tf, err := analysisutil.ReadFile(pass, filename)
+	content, tf, err := analysisinternal.ReadFile(pass, filename)
 	if err != nil {
 		return err
 	}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/errorsas/errorsas.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/errorsas/errorsas.go
index b8d29d019db0b0..b3df99929dc6fc 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/errorsas/errorsas.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/errorsas/errorsas.go
@@ -12,22 +12,20 @@ import (
 	"go/types"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/go/types/typeutil"
-	"golang.org/x/tools/internal/analysisinternal"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
 )
 
 const Doc = `report passing non-pointer or non-error values to errors.As
 
-The errorsas analysis reports calls to errors.As where the type
+The errorsas analyzer reports calls to errors.As where the type
 of the second argument is not a pointer to a type implementing error.`
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "errorsas",
 	Doc:      Doc,
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/errorsas",
-	Requires: []*analysis.Analyzer{inspect.Analyzer},
+	Requires: []*analysis.Analyzer{typeindexanalyzer.Analyzer},
 	Run:      run,
 }
 
@@ -39,38 +37,31 @@ func run(pass *analysis.Pass) (any, error) {
 		return nil, nil
 	}
 
-	if !analysisinternal.Imports(pass.Pkg, "errors") {
-		return nil, nil // doesn't directly import errors
-	}
-
-	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	var (
+		index = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info  = pass.TypesInfo
+	)
 
-	nodeFilter := []ast.Node{
-		(*ast.CallExpr)(nil),
-	}
-	inspect.Preorder(nodeFilter, func(n ast.Node) {
-		call := n.(*ast.CallExpr)
-		obj := typeutil.Callee(pass.TypesInfo, call)
-		if !analysisinternal.IsFunctionNamed(obj, "errors", "As") {
-			return
-		}
+	for curCall := range index.Calls(index.Object("errors", "As")) {
+		call := curCall.Node().(*ast.CallExpr)
 		if len(call.Args) < 2 {
-			return // not enough arguments, e.g. called with return values of another function
+			continue // spread call: errors.As(pair())
 		}
-		if err := checkAsTarget(pass, call.Args[1]); err != nil {
+
+		// Check for incorrect arguments.
+		if err := checkAsTarget(info, call.Args[1]); err != nil {
 			pass.ReportRangef(call, "%v", err)
+			continue
 		}
-	})
+	}
 	return nil, nil
 }
 
-var errorType = types.Universe.Lookup("error").Type()
-
 // checkAsTarget reports an error if the second argument to errors.As is invalid.
-func checkAsTarget(pass *analysis.Pass, e ast.Expr) error {
-	t := pass.TypesInfo.Types[e].Type
-	if it, ok := t.Underlying().(*types.Interface); ok && it.NumMethods() == 0 {
-		// A target of interface{} is always allowed, since it often indicates
+func checkAsTarget(info *types.Info, e ast.Expr) error {
+	t := info.Types[e].Type
+	if types.Identical(t.Underlying(), anyType) {
+		// A target of any is always allowed, since it often indicates
 		// a value forwarded from another source.
 		return nil
 	}
@@ -78,12 +69,16 @@ func checkAsTarget(pass *analysis.Pass, e ast.Expr) error {
 	if !ok {
 		return errors.New("second argument to errors.As must be a non-nil pointer to either a type that implements error, or to any interface type")
 	}
-	if pt.Elem() == errorType {
+	if types.Identical(pt.Elem(), errorType) {
 		return errors.New("second argument to errors.As should not be *error")
 	}
-	_, ok = pt.Elem().Underlying().(*types.Interface)
-	if ok || types.Implements(pt.Elem(), errorType.Underlying().(*types.Interface)) {
-		return nil
+	if !types.IsInterface(pt.Elem()) && !types.AssignableTo(pt.Elem(), errorType) {
+		return errors.New("second argument to errors.As must be a non-nil pointer to either a type that implements error, or to any interface type")
 	}
-	return errors.New("second argument to errors.As must be a non-nil pointer to either a type that implements error, or to any interface type")
+	return nil
 }
+
+var (
+	anyType   = types.Universe.Lookup("any").Type()
+	errorType = types.Universe.Lookup("error").Type()
+)
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/framepointer/framepointer.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/framepointer/framepointer.go
index ff9c8b4f818b10..809095d40a5456 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/framepointer/framepointer.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/framepointer/framepointer.go
@@ -13,7 +13,7 @@ import (
 	"unicode"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+	"golang.org/x/tools/internal/analysisinternal"
 )
 
 const Doc = "report assembly that clobbers the frame pointer before saving it"
@@ -98,7 +98,7 @@ func run(pass *analysis.Pass) (any, error) {
 	}
 
 	for _, fname := range sfiles {
-		content, tf, err := analysisutil.ReadFile(pass, fname)
+		content, tf, err := analysisinternal.ReadFile(pass, fname)
 		if err != nil {
 			return nil, err
 		}
@@ -127,7 +127,7 @@ func run(pass *analysis.Pass) (any, error) {
 			}
 
 			if arch.isFPWrite(line) {
-				pass.Reportf(analysisutil.LineStart(tf, lineno), "frame pointer is clobbered before saving")
+				pass.Reportf(tf.LineStart(lineno), "frame pointer is clobbered before saving")
 				active = false
 				continue
 			}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/httpresponse/httpresponse.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/httpresponse/httpresponse.go
index e9acd96547e1a7..37ecb6523bd1ca 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/httpresponse/httpresponse.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/httpresponse/httpresponse.go
@@ -13,7 +13,6 @@ import (
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/analysisinternal"
 	"golang.org/x/tools/internal/typesinternal"
 )
 
@@ -46,7 +45,7 @@ func run(pass *analysis.Pass) (any, error) {
 
 	// Fast path: if the package doesn't import net/http,
 	// skip the traversal.
-	if !analysisinternal.Imports(pass.Pkg, "net/http") {
+	if !typesinternal.Imports(pass.Pkg, "net/http") {
 		return nil, nil
 	}
 
@@ -118,7 +117,7 @@ func isHTTPFuncOrMethodOnClient(info *types.Info, expr *ast.CallExpr) bool {
 		return false // the function called does not return two values.
 	}
 	isPtr, named := typesinternal.ReceiverNamed(res.At(0))
-	if !isPtr || named == nil || !analysisinternal.IsTypeNamed(named, "net/http", "Response") {
+	if !isPtr || named == nil || !typesinternal.IsTypeNamed(named, "net/http", "Response") {
 		return false // the first return type is not *http.Response.
 	}
 
@@ -133,11 +132,11 @@ func isHTTPFuncOrMethodOnClient(info *types.Info, expr *ast.CallExpr) bool {
 		return ok && id.Name == "http" // function in net/http package.
 	}
 
-	if analysisinternal.IsTypeNamed(typ, "net/http", "Client") {
+	if typesinternal.IsTypeNamed(typ, "net/http", "Client") {
 		return true // method on http.Client.
 	}
 	ptr, ok := types.Unalias(typ).(*types.Pointer)
-	return ok && analysisinternal.IsTypeNamed(ptr.Elem(), "net/http", "Client") // method on *http.Client.
+	return ok && typesinternal.IsTypeNamed(ptr.Elem(), "net/http", "Client") // method on *http.Client.
 }
 
 // restOfBlock, given a traversal stack, finds the innermost containing
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/ifaceassert/ifaceassert.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/ifaceassert/ifaceassert.go
index 4022dbe7c22cce..a6dcf1cf8e8e1d 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/ifaceassert/ifaceassert.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/ifaceassert/ifaceassert.go
@@ -11,8 +11,8 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -21,7 +21,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "ifaceassert",
-	Doc:      analysisutil.MustExtractDoc(doc, "ifaceassert"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "ifaceassert"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/ifaceassert",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/internal/analysisutil/util.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/internal/analysisutil/util.go
deleted file mode 100644
index d3df898d3011cd..00000000000000
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/internal/analysisutil/util.go
+++ /dev/null
@@ -1,99 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package analysisutil defines various helper functions
-// used by two or more packages beneath go/analysis.
-package analysisutil
-
-import (
-	"go/ast"
-	"go/token"
-	"go/types"
-	"os"
-
-	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/internal/analysisinternal"
-)
-
-// HasSideEffects reports whether evaluation of e has side effects.
-func HasSideEffects(info *types.Info, e ast.Expr) bool {
-	safe := true
-	ast.Inspect(e, func(node ast.Node) bool {
-		switch n := node.(type) {
-		case *ast.CallExpr:
-			typVal := info.Types[n.Fun]
-			switch {
-			case typVal.IsType():
-				// Type conversion, which is safe.
-			case typVal.IsBuiltin():
-				// Builtin func, conservatively assumed to not
-				// be safe for now.
-				safe = false
-				return false
-			default:
-				// A non-builtin func or method call.
-				// Conservatively assume that all of them have
-				// side effects for now.
-				safe = false
-				return false
-			}
-		case *ast.UnaryExpr:
-			if n.Op == token.ARROW {
-				safe = false
-				return false
-			}
-		}
-		return true
-	})
-	return !safe
-}
-
-// ReadFile reads a file and adds it to the FileSet
-// so that we can report errors against it using lineStart.
-func ReadFile(pass *analysis.Pass, filename string) ([]byte, *token.File, error) {
-	readFile := pass.ReadFile
-	if readFile == nil {
-		readFile = os.ReadFile
-	}
-	content, err := readFile(filename)
-	if err != nil {
-		return nil, nil, err
-	}
-	tf := pass.Fset.AddFile(filename, -1, len(content))
-	tf.SetLinesForContent(content)
-	return content, tf, nil
-}
-
-// LineStart returns the position of the start of the specified line
-// within file f, or NoPos if there is no line of that number.
-func LineStart(f *token.File, line int) token.Pos {
-	// Use binary search to find the start offset of this line.
-	//
-	// TODO(adonovan): eventually replace this function with the
-	// simpler and more efficient (*go/token.File).LineStart, added
-	// in go1.12.
-
-	min := 0        // inclusive
-	max := f.Size() // exclusive
-	for {
-		offset := (min + max) / 2
-		pos := f.Pos(offset)
-		posn := f.Position(pos)
-		if posn.Line == line {
-			return pos - (token.Pos(posn.Column) - 1)
-		}
-
-		if min+1 >= max {
-			return token.NoPos
-		}
-
-		if posn.Line < line {
-			min = offset
-		} else {
-			max = offset
-		}
-	}
-}
-
-var MustExtractDoc = analysisinternal.MustExtractDoc
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/loopclosure/loopclosure.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/loopclosure/loopclosure.go
index 2580a0ac21f1f9..868226328fc5e1 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/loopclosure/loopclosure.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/loopclosure/loopclosure.go
@@ -11,7 +11,6 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
@@ -24,7 +23,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "loopclosure",
-	Doc:      analysisutil.MustExtractDoc(doc, "loopclosure"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "loopclosure"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/loopclosure",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
@@ -369,5 +368,5 @@ func isMethodCall(info *types.Info, expr ast.Expr, pkgPath, typeName, method str
 	// Check that the receiver is a . or
 	// *..
 	_, named := typesinternal.ReceiverNamed(recv)
-	return analysisinternal.IsTypeNamed(named, pkgPath, typeName)
+	return typesinternal.IsTypeNamed(named, pkgPath, typeName)
 }
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go
index c0746789e9cb2a..dfaecf51e25a2b 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/lostcancel/lostcancel.go
@@ -13,11 +13,11 @@ import (
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/ctrlflow"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/cfg"
 	"golang.org/x/tools/internal/analysisinternal"
 	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 //go:embed doc.go
@@ -25,7 +25,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name: "lostcancel",
-	Doc:  analysisutil.MustExtractDoc(doc, "lostcancel"),
+	Doc:  analysisinternal.MustExtractDoc(doc, "lostcancel"),
 	URL:  "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/lostcancel",
 	Run:  run,
 	Requires: []*analysis.Analyzer{
@@ -50,7 +50,7 @@ var contextPackage = "context"
 // checkLostCancel analyzes a single named or literal function.
 func run(pass *analysis.Pass) (any, error) {
 	// Fast path: bypass check if file doesn't use context.WithCancel.
-	if !analysisinternal.Imports(pass.Pkg, contextPackage) {
+	if !typesinternal.Imports(pass.Pkg, contextPackage) {
 		return nil, nil
 	}
 
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/nilfunc/nilfunc.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/nilfunc/nilfunc.go
index fa1883b0c3402c..2b5a7c80378828 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/nilfunc/nilfunc.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/nilfunc/nilfunc.go
@@ -14,8 +14,8 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
 	"golang.org/x/tools/internal/typesinternal"
 )
 
@@ -24,7 +24,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "nilfunc",
-	Doc:      analysisutil.MustExtractDoc(doc, "nilfunc"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "nilfunc"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/nilfunc",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/printf/doc.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/printf/doc.go
index eebf40208d1816..f04e44143412a4 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/printf/doc.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/printf/doc.go
@@ -82,6 +82,16 @@
 //		...
 //	}
 //
+// A local function may also be inferred as a printf wrapper. If it
+// is assigned to a variable, each call made through that variable will
+// be checked just like a call to a function:
+//
+//	logf := func(format string, args ...any) {
+//		message := fmt.Sprintf(format, args...)
+//		log.Printf("%s: %s", prefix, message)
+//	}
+//	logf("%s", 123) // logf format %s has arg 123 of wrong type int
+//
 // # Specifying printf wrappers by flag
 //
 // The -funcs flag specifies a comma-separated list of names of
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/printf/printf.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/printf/printf.go
index f008eca36fe3c1..910ffe70d7e33a 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/printf/printf.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/printf/printf.go
@@ -18,13 +18,14 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+	"golang.org/x/tools/go/ast/edge"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
 	"golang.org/x/tools/internal/astutil"
 	"golang.org/x/tools/internal/fmtstr"
 	"golang.org/x/tools/internal/typeparams"
+	"golang.org/x/tools/internal/typesinternal"
 	"golang.org/x/tools/internal/versions"
 )
 
@@ -37,11 +38,11 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:       "printf",
-	Doc:        analysisutil.MustExtractDoc(doc, "printf"),
+	Doc:        analysisinternal.MustExtractDoc(doc, "printf"),
 	URL:        "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/printf",
 	Requires:   []*analysis.Analyzer{inspect.Analyzer},
 	Run:        run,
-	ResultType: reflect.TypeOf((*Result)(nil)),
+	ResultType: reflect.TypeFor[*Result](),
 	FactTypes:  []analysis.Fact{new(isWrapper)},
 }
 
@@ -70,7 +71,7 @@ func (kind Kind) String() string {
 // Result is the printf analyzer's result type. Clients may query the result
 // to learn whether a function behaves like fmt.Print or fmt.Printf.
 type Result struct {
-	funcs map[*types.Func]Kind
+	funcs map[types.Object]Kind
 }
 
 // Kind reports whether fn behaves like fmt.Print or fmt.Printf.
@@ -111,149 +112,210 @@ func (f *isWrapper) String() string {
 
 func run(pass *analysis.Pass) (any, error) {
 	res := &Result{
-		funcs: make(map[*types.Func]Kind),
+		funcs: make(map[types.Object]Kind),
 	}
-	findPrintfLike(pass, res)
-	checkCalls(pass)
+	findPrintLike(pass, res)
+	checkCalls(pass, res)
 	return res, nil
 }
 
-type printfWrapper struct {
-	obj     *types.Func
-	fdecl   *ast.FuncDecl
-	format  *types.Var
-	args    *types.Var
+// A wrapper is a candidate print/printf wrapper function.
+//
+// We represent functions generally as types.Object, not *Func, so
+// that we can analyze anonymous functions such as
+//
+//	printf := func(format string, args ...any) {...},
+//
+// representing them by the *types.Var symbol for the local variable
+// 'printf'.
+type wrapper struct {
+	obj     types.Object     // *Func or *Var
+	curBody inspector.Cursor // for *ast.BlockStmt
+	format  *types.Var       // optional "format string" parameter in the Func{Decl,Lit}
+	args    *types.Var       // "args ...any" parameter in the Func{Decl,Lit}
 	callers []printfCaller
-	failed  bool // if true, not a printf wrapper
 }
 
 type printfCaller struct {
-	w    *printfWrapper
+	w    *wrapper
 	call *ast.CallExpr
 }
 
-// maybePrintfWrapper decides whether decl (a declared function) may be a wrapper
-// around a fmt.Printf or fmt.Print function. If so it returns a printfWrapper
-// function describing the declaration. Later processing will analyze the
-// graph of potential printf wrappers to pick out the ones that are true wrappers.
-// A function may be a Printf or Print wrapper if its last argument is ...interface{}.
-// If the next-to-last argument is a string, then this may be a Printf wrapper.
-// Otherwise it may be a Print wrapper.
-func maybePrintfWrapper(info *types.Info, decl ast.Decl) *printfWrapper {
-	// Look for functions with final argument type ...interface{}.
-	fdecl, ok := decl.(*ast.FuncDecl)
-	if !ok || fdecl.Body == nil {
-		return nil
-	}
-	fn, ok := info.Defs[fdecl.Name].(*types.Func)
-	// Type information may be incomplete.
-	if !ok {
-		return nil
-	}
-
-	sig := fn.Type().(*types.Signature)
+// formatArgsParams returns the "format string" and "args ...any"
+// parameters of a potential print or printf wrapper function.
+// (The format is nil in the print-like case.)
+func formatArgsParams(sig *types.Signature) (format, args *types.Var) {
 	if !sig.Variadic() {
-		return nil // not variadic
+		return nil, nil // not variadic
 	}
 
 	params := sig.Params()
 	nparams := params.Len() // variadic => nonzero
 
-	// Check final parameter is "args ...interface{}".
-	args := params.At(nparams - 1)
-	iface, ok := types.Unalias(args.Type().(*types.Slice).Elem()).(*types.Interface)
-	if !ok || !iface.Empty() {
-		return nil
-	}
-
 	// Is second last param 'format string'?
-	var format *types.Var
 	if nparams >= 2 {
 		if p := params.At(nparams - 2); p.Type() == types.Typ[types.String] {
 			format = p
 		}
 	}
 
-	return &printfWrapper{
-		obj:    fn,
-		fdecl:  fdecl,
-		format: format,
-		args:   args,
+	// Check final parameter is "args ...any".
+	// (variadic => slice)
+	args = params.At(nparams - 1)
+	iface, ok := types.Unalias(args.Type().(*types.Slice).Elem()).(*types.Interface)
+	if !ok || !iface.Empty() {
+		return nil, nil
 	}
+
+	return format, args
 }
 
-// findPrintfLike scans the entire package to find printf-like functions.
-func findPrintfLike(pass *analysis.Pass, res *Result) (any, error) {
-	// Gather potential wrappers and call graph between them.
-	byObj := make(map[*types.Func]*printfWrapper)
-	var wrappers []*printfWrapper
-	for _, file := range pass.Files {
-		for _, decl := range file.Decls {
-			w := maybePrintfWrapper(pass.TypesInfo, decl)
-			if w == nil {
-				continue
+// findPrintLike scans the entire package to find print or printf-like functions.
+// When it returns, all such functions have been identified.
+func findPrintLike(pass *analysis.Pass, res *Result) {
+	var (
+		inspect = pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		info    = pass.TypesInfo
+	)
+
+	// Pass 1: gather candidate wrapper functions (and populate wrappers).
+	var (
+		wrappers []*wrapper
+		byObj    = make(map[types.Object]*wrapper)
+	)
+	for cur := range inspect.Root().Preorder((*ast.FuncDecl)(nil), (*ast.FuncLit)(nil)) {
+		var (
+			curBody inspector.Cursor // for *ast.BlockStmt
+			sig     *types.Signature
+			obj     types.Object
+		)
+		switch f := cur.Node().(type) {
+		case *ast.FuncDecl:
+			// named function or method:
+			//
+			//    func wrapf(format string, args ...any) {...}
+			if f.Body != nil {
+				curBody = cur.ChildAt(edge.FuncDecl_Body, -1)
+				obj = info.Defs[f.Name]
+				sig = obj.Type().(*types.Signature)
 			}
-			byObj[w.obj] = w
-			wrappers = append(wrappers, w)
-		}
-	}
 
-	// Walk the graph to figure out which are really printf wrappers.
-	for _, w := range wrappers {
-		// Scan function for calls that could be to other printf-like functions.
-		ast.Inspect(w.fdecl.Body, func(n ast.Node) bool {
-			if w.failed {
-				return false
+		case *ast.FuncLit:
+			// anonymous function directly assigned to a variable:
+			//
+			//    var wrapf = func(format string, args ...any) {...}
+			//    wrapf    := func(format string, args ...any) {...}
+			//    wrapf     = func(format string, args ...any) {...}
+			//
+			// The LHS may also be a struct field x.wrapf or
+			// an imported var pkg.Wrapf.
+			//
+			sig = info.TypeOf(f).(*types.Signature)
+			curBody = cur.ChildAt(edge.FuncLit_Body, -1)
+			var lhs ast.Expr
+			switch ek, idx := cur.ParentEdge(); ek {
+			case edge.ValueSpec_Values:
+				curName := cur.Parent().ChildAt(edge.ValueSpec_Names, idx)
+				lhs = curName.Node().(*ast.Ident)
+			case edge.AssignStmt_Rhs:
+				curLhs := cur.Parent().ChildAt(edge.AssignStmt_Lhs, idx)
+				lhs = curLhs.Node().(ast.Expr)
 			}
 
-			// TODO: Relax these checks; issue 26555.
-			if assign, ok := n.(*ast.AssignStmt); ok {
-				for _, lhs := range assign.Lhs {
-					if match(pass.TypesInfo, lhs, w.format) ||
-						match(pass.TypesInfo, lhs, w.args) {
-						// Modifies the format
-						// string or args in
-						// some way, so not a
-						// simple wrapper.
-						w.failed = true
-						return false
-					}
+			switch lhs := lhs.(type) {
+			case *ast.Ident:
+				// variable: wrapf = func(...)
+				obj = info.ObjectOf(lhs).(*types.Var)
+			case *ast.SelectorExpr:
+				if sel, ok := info.Selections[lhs]; ok {
+					// struct field: x.wrapf = func(...)
+					obj = sel.Obj().(*types.Var)
+				} else {
+					// imported var: pkg.Wrapf = func(...)
+					obj = info.Uses[lhs.Sel].(*types.Var)
 				}
 			}
-			if un, ok := n.(*ast.UnaryExpr); ok && un.Op == token.AND {
-				if match(pass.TypesInfo, un.X, w.format) ||
-					match(pass.TypesInfo, un.X, w.args) {
-					// Taking the address of the
-					// format string or args,
-					// so not a simple wrapper.
-					w.failed = true
-					return false
+		}
+		if obj != nil {
+			format, args := formatArgsParams(sig)
+			if args != nil {
+				// obj (the symbol for a function/method, or variable
+				// assigned to an anonymous function) is a potential
+				// print or printf wrapper.
+				//
+				// Later processing will analyze the graph of potential
+				// wrappers and their function bodies to pick out the
+				// ones that are true wrappers.
+				w := &wrapper{
+					obj:     obj,
+					curBody: curBody,
+					format:  format, // non-nil => printf
+					args:    args,
 				}
+				byObj[w.obj] = w
+				wrappers = append(wrappers, w)
 			}
+		}
+	}
 
-			call, ok := n.(*ast.CallExpr)
-			if !ok || len(call.Args) == 0 || !match(pass.TypesInfo, call.Args[len(call.Args)-1], w.args) {
-				return true
-			}
+	// Pass 2: scan the body of each wrapper function
+	// for calls to other printf-like functions.
+	//
+	// Also, reject tricky cases where the parameters
+	// are potentially mutated by AssignStmt or UnaryExpr.
+	// TODO: Relax these checks; issue 26555.
+	for _, w := range wrappers {
+	scan:
+		for cur := range w.curBody.Preorder(
+			(*ast.AssignStmt)(nil),
+			(*ast.UnaryExpr)(nil),
+			(*ast.CallExpr)(nil),
+		) {
+			switch n := cur.Node().(type) {
+			case *ast.AssignStmt:
+				// If the wrapper updates format or args
+				// it is not a simple wrapper.
+				for _, lhs := range n.Lhs {
+					if w.format != nil && match(info, lhs, w.format) ||
+						match(info, lhs, w.args) {
+						break scan
+					}
+				}
 
-			fn, kind := printfNameAndKind(pass, call)
-			if kind != 0 {
-				checkPrintfFwd(pass, w, call, kind, res)
-				return true
-			}
+			case *ast.UnaryExpr:
+				// If the wrapper computes &format or &args,
+				// it is not a simple wrapper.
+				if n.Op == token.AND &&
+					(w.format != nil && match(info, n.X, w.format) ||
+						match(info, n.X, w.args)) {
+					break scan
+				}
 
-			// If the call is to another function in this package,
-			// maybe we will find out it is printf-like later.
-			// Remember this call for later checking.
-			if fn != nil && fn.Pkg() == pass.Pkg && byObj[fn] != nil {
-				callee := byObj[fn]
-				callee.callers = append(callee.callers, printfCaller{w, call})
+			case *ast.CallExpr:
+				if len(n.Args) > 0 && match(info, n.Args[len(n.Args)-1], w.args) {
+					if callee := typeutil.Callee(pass.TypesInfo, n); callee != nil {
+
+						// Call from one wrapper candidate to another?
+						// Record the edge so that if callee is found to be
+						// a true wrapper, w will be too.
+						if w2, ok := byObj[callee]; ok {
+							w2.callers = append(w2.callers, printfCaller{w, n})
+						}
+
+						// Is the candidate a true wrapper, because it calls
+						// a known print{,f}-like function from the allowlist
+						// or an imported fact, or another wrapper found
+						// to be a true wrapper?
+						// If so, convert all w's callers to kind.
+						kind := callKind(pass, callee, res)
+						if kind != KindNone {
+							checkForward(pass, w, n, kind, res)
+						}
+					}
+				}
 			}
-
-			return true
-		})
+		}
 	}
-	return nil, nil
 }
 
 func match(info *types.Info, arg ast.Expr, param *types.Var) bool {
@@ -261,9 +323,9 @@ func match(info *types.Info, arg ast.Expr, param *types.Var) bool {
 	return ok && info.ObjectOf(id) == param
 }
 
-// checkPrintfFwd checks that a printf-forwarding wrapper is forwarding correctly.
+// checkForward checks that a forwarding wrapper is forwarding correctly.
 // It diagnoses writing fmt.Printf(format, args) instead of fmt.Printf(format, args...).
-func checkPrintfFwd(pass *analysis.Pass, w *printfWrapper, call *ast.CallExpr, kind Kind, res *Result) {
+func checkForward(pass *analysis.Pass, w *wrapper, call *ast.CallExpr, kind Kind, res *Result) {
 	matched := kind == KindPrint ||
 		kind != KindNone && len(call.Args) >= 2 && match(pass.TypesInfo, call.Args[len(call.Args)-2], w.format)
 	if !matched {
@@ -292,18 +354,39 @@ func checkPrintfFwd(pass *analysis.Pass, w *printfWrapper, call *ast.CallExpr, k
 		pass.ReportRangef(call, "missing ... in args forwarded to %s-like function", desc)
 		return
 	}
-	fn := w.obj
-	var fact isWrapper
-	if !pass.ImportObjectFact(fn, &fact) {
-		fact.Kind = kind
-		pass.ExportObjectFact(fn, &fact)
-		res.funcs[fn] = kind
+
+	// If the candidate's print{,f} status becomes known,
+	// propagate it back to all its so-far known callers.
+	if res.funcs[w.obj] != kind {
+		res.funcs[w.obj] = kind
+
+		// Export a fact.
+		// (This is a no-op for local symbols.)
+		// We can't export facts on a symbol of another package,
+		// but we can treat the symbol as a wrapper within
+		// the current analysis unit.
+		if w.obj.Pkg() == pass.Pkg {
+			// Facts are associated with origins.
+			pass.ExportObjectFact(origin(w.obj), &isWrapper{Kind: kind})
+		}
+
+		// Propagate kind back to known callers.
 		for _, caller := range w.callers {
-			checkPrintfFwd(pass, caller.w, caller.call, kind, res)
+			checkForward(pass, caller.w, caller.call, kind, res)
 		}
 	}
 }
 
+func origin(obj types.Object) types.Object {
+	switch obj := obj.(type) {
+	case *types.Func:
+		return obj.Origin()
+	case *types.Var:
+		return obj.Origin()
+	}
+	return obj
+}
+
 // isPrint records the print functions.
 // If a key ends in 'f' then it is assumed to be a formatted print.
 //
@@ -412,7 +495,7 @@ func stringConstantExpr(pass *analysis.Pass, expr ast.Expr) (string, bool) {
 
 // checkCalls triggers the print-specific checks for calls that invoke a print
 // function.
-func checkCalls(pass *analysis.Pass) {
+func checkCalls(pass *analysis.Pass, res *Result) {
 	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
 	nodeFilter := []ast.Node{
 		(*ast.File)(nil),
@@ -426,48 +509,60 @@ func checkCalls(pass *analysis.Pass) {
 			fileVersion = versions.Lang(versions.FileVersion(pass.TypesInfo, n))
 
 		case *ast.CallExpr:
-			fn, kind := printfNameAndKind(pass, n)
-			switch kind {
-			case KindPrintf, KindErrorf:
-				checkPrintf(pass, fileVersion, kind, n, fn.FullName())
-			case KindPrint:
-				checkPrint(pass, n, fn.FullName())
+			if callee := typeutil.Callee(pass.TypesInfo, n); callee != nil {
+				kind := callKind(pass, callee, res)
+				switch kind {
+				case KindPrintf, KindErrorf:
+					checkPrintf(pass, fileVersion, kind, n, fullname(callee))
+				case KindPrint:
+					checkPrint(pass, n, fullname(callee))
+				}
 			}
 		}
 	})
 }
 
-func printfNameAndKind(pass *analysis.Pass, call *ast.CallExpr) (fn *types.Func, kind Kind) {
-	fn, _ = typeutil.Callee(pass.TypesInfo, call).(*types.Func)
-	if fn == nil {
-		return nil, 0
+func fullname(obj types.Object) string {
+	if fn, ok := obj.(*types.Func); ok {
+		return fn.FullName()
 	}
+	return obj.Name()
+}
 
-	// Facts are associated with generic declarations, not instantiations.
-	fn = fn.Origin()
-
-	_, ok := isPrint[fn.FullName()]
+// callKind returns the symbol of the called function
+// and its print/printf kind, if any.
+// (The symbol may be a var for an anonymous function.)
+// The result is memoized in res.funcs.
+func callKind(pass *analysis.Pass, obj types.Object, res *Result) Kind {
+	kind, ok := res.funcs[obj]
 	if !ok {
-		// Next look up just "printf", for use with -printf.funcs.
-		_, ok = isPrint[strings.ToLower(fn.Name())]
-	}
-	if ok {
-		if fn.FullName() == "fmt.Errorf" {
-			kind = KindErrorf
-		} else if strings.HasSuffix(fn.Name(), "f") {
-			kind = KindPrintf
+		// cache miss
+		_, ok := isPrint[fullname(obj)]
+		if !ok {
+			// Next look up just "printf", for use with -printf.funcs.
+			_, ok = isPrint[strings.ToLower(obj.Name())]
+		}
+		if ok {
+			// well-known printf functions
+			if fullname(obj) == "fmt.Errorf" {
+				kind = KindErrorf
+			} else if strings.HasSuffix(obj.Name(), "f") {
+				kind = KindPrintf
+			} else {
+				kind = KindPrint
+			}
 		} else {
-			kind = KindPrint
+			// imported wrappers
+			// Facts are associated with generic declarations, not instantiations.
+			obj = origin(obj)
+			var fact isWrapper
+			if pass.ImportObjectFact(obj, &fact) {
+				kind = fact.Kind
+			}
 		}
-		return fn, kind
+		res.funcs[obj] = kind // cache
 	}
-
-	var fact isWrapper
-	if pass.ImportObjectFact(fn, &fact) {
-		return fn, fact.Kind
-	}
-
-	return fn, KindNone
+	return kind
 }
 
 // isFormatter reports whether t could satisfy fmt.Formatter.
@@ -490,7 +585,7 @@ func isFormatter(typ types.Type) bool {
 	sig := fn.Type().(*types.Signature)
 	return sig.Params().Len() == 2 &&
 		sig.Results().Len() == 0 &&
-		analysisinternal.IsTypeNamed(sig.Params().At(0).Type(), "fmt", "State") &&
+		typesinternal.IsTypeNamed(sig.Params().At(0).Type(), "fmt", "State") &&
 		types.Identical(sig.Params().At(1).Type(), types.Typ[types.Rune])
 }
 
@@ -729,7 +824,7 @@ func okPrintfArg(pass *analysis.Pass, call *ast.CallExpr, rng analysis.Range, ma
 			if reason != "" {
 				details = " (" + reason + ")"
 			}
-			pass.ReportRangef(rng, "%s format %s uses non-int %s%s as argument of *", name, operation.Text, analysisinternal.Format(pass.Fset, arg), details)
+			pass.ReportRangef(rng, "%s format %s uses non-int %s%s as argument of *", name, operation.Text, astutil.Format(pass.Fset, arg), details)
 			return false
 		}
 	}
@@ -756,7 +851,7 @@ func okPrintfArg(pass *analysis.Pass, call *ast.CallExpr, rng analysis.Range, ma
 	}
 	arg := call.Args[verbArgIndex]
 	if isFunctionValue(pass, arg) && verb != 'p' && verb != 'T' {
-		pass.ReportRangef(rng, "%s format %s arg %s is a func value, not called", name, operation.Text, analysisinternal.Format(pass.Fset, arg))
+		pass.ReportRangef(rng, "%s format %s arg %s is a func value, not called", name, operation.Text, astutil.Format(pass.Fset, arg))
 		return false
 	}
 	if reason, ok := matchArgType(pass, v.typ, arg); !ok {
@@ -768,14 +863,14 @@ func okPrintfArg(pass *analysis.Pass, call *ast.CallExpr, rng analysis.Range, ma
 		if reason != "" {
 			details = " (" + reason + ")"
 		}
-		pass.ReportRangef(rng, "%s format %s has arg %s of wrong type %s%s", name, operation.Text, analysisinternal.Format(pass.Fset, arg), typeString, details)
+		pass.ReportRangef(rng, "%s format %s has arg %s of wrong type %s%s", name, operation.Text, astutil.Format(pass.Fset, arg), typeString, details)
 		return false
 	}
 	// Detect recursive formatting via value's String/Error methods.
 	// The '#' flag suppresses the methods, except with %x, %X, and %q.
 	if v.typ&argString != 0 && v.verb != 'T' && (!strings.Contains(operation.Flags, "#") || strings.ContainsRune("qxX", v.verb)) {
 		if methodName, ok := recursiveStringer(pass, arg); ok {
-			pass.ReportRangef(rng, "%s format %s with arg %s causes recursive %s method call", name, operation.Text, analysisinternal.Format(pass.Fset, arg), methodName)
+			pass.ReportRangef(rng, "%s format %s with arg %s causes recursive %s method call", name, operation.Text, astutil.Format(pass.Fset, arg), methodName)
 			return false
 		}
 	}
@@ -927,7 +1022,7 @@ func checkPrint(pass *analysis.Pass, call *ast.CallExpr, name string) {
 		if sel, ok := call.Args[0].(*ast.SelectorExpr); ok {
 			if x, ok := sel.X.(*ast.Ident); ok {
 				if x.Name == "os" && strings.HasPrefix(sel.Sel.Name, "Std") {
-					pass.ReportRangef(call, "%s does not take io.Writer but has first arg %s", name, analysisinternal.Format(pass.Fset, call.Args[0]))
+					pass.ReportRangef(call, "%s does not take io.Writer but has first arg %s", name, astutil.Format(pass.Fset, call.Args[0]))
 				}
 			}
 		}
@@ -961,10 +1056,10 @@ func checkPrint(pass *analysis.Pass, call *ast.CallExpr, name string) {
 	}
 	for _, arg := range args {
 		if isFunctionValue(pass, arg) {
-			pass.ReportRangef(call, "%s arg %s is a func value, not called", name, analysisinternal.Format(pass.Fset, arg))
+			pass.ReportRangef(call, "%s arg %s is a func value, not called", name, astutil.Format(pass.Fset, arg))
 		}
 		if methodName, ok := recursiveStringer(pass, arg); ok {
-			pass.ReportRangef(call, "%s arg %s causes recursive call to %s method", name, analysisinternal.Format(pass.Fset, arg), methodName)
+			pass.ReportRangef(call, "%s arg %s causes recursive call to %s method", name, astutil.Format(pass.Fset, arg), methodName)
 		}
 	}
 }
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/shift/shift.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/shift/shift.go
index 57987b3d203a75..366927326fcede 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/shift/shift.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/shift/shift.go
@@ -20,7 +20,7 @@ import (
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -123,7 +123,7 @@ func checkLongShift(pass *analysis.Pass, node ast.Node, x, y ast.Expr) {
 		}
 	}
 	if amt >= minSize {
-		ident := analysisinternal.Format(pass.Fset, x)
+		ident := astutil.Format(pass.Fset, x)
 		qualifier := ""
 		if len(sizes) > 1 {
 			qualifier = "may be "
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/sigchanyzer/sigchanyzer.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/sigchanyzer/sigchanyzer.go
index 78a2fa5ea3bd34..934f3913c2763b 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/sigchanyzer/sigchanyzer.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/sigchanyzer/sigchanyzer.go
@@ -18,9 +18,9 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 //go:embed doc.go
@@ -29,14 +29,14 @@ var doc string
 // Analyzer describes sigchanyzer analysis function detector.
 var Analyzer = &analysis.Analyzer{
 	Name:     "sigchanyzer",
-	Doc:      analysisutil.MustExtractDoc(doc, "sigchanyzer"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "sigchanyzer"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/sigchanyzer",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
 }
 
 func run(pass *analysis.Pass) (any, error) {
-	if !analysisinternal.Imports(pass.Pkg, "os/signal") {
+	if !typesinternal.Imports(pass.Pkg, "os/signal") {
 		return nil, nil // doesn't directly import signal
 	}
 
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/slog/slog.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/slog/slog.go
index c1ac960435d41f..2cb91c73299374 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/slog/slog.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/slog/slog.go
@@ -17,10 +17,10 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
 	"golang.org/x/tools/internal/typesinternal"
 )
 
@@ -29,7 +29,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "slog",
-	Doc:      analysisutil.MustExtractDoc(doc, "slog"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "slog"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/slog",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
@@ -115,10 +115,10 @@ func run(pass *analysis.Pass) (any, error) {
 				default:
 					if unknownArg == nil {
 						pass.ReportRangef(arg, "%s arg %q should be a string or a slog.Attr (possible missing key or value)",
-							shortName(fn), analysisinternal.Format(pass.Fset, arg))
+							shortName(fn), astutil.Format(pass.Fset, arg))
 					} else {
 						pass.ReportRangef(arg, "%s arg %q should probably be a string or a slog.Attr (previous arg %q cannot be a key)",
-							shortName(fn), analysisinternal.Format(pass.Fset, arg), analysisinternal.Format(pass.Fset, unknownArg))
+							shortName(fn), astutil.Format(pass.Fset, arg), astutil.Format(pass.Fset, unknownArg))
 					}
 					// Stop here so we report at most one missing key per call.
 					return
@@ -158,7 +158,7 @@ func run(pass *analysis.Pass) (any, error) {
 }
 
 func isAttr(t types.Type) bool {
-	return analysisinternal.IsTypeNamed(t, "log/slog", "Attr")
+	return typesinternal.IsTypeNamed(t, "log/slog", "Attr")
 }
 
 // shortName returns a name for the function that is shorter than FullName.
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go
index a0bdf001abd602..ca303ae5c15c6d 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stdmethods/stdmethods.go
@@ -12,8 +12,8 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
 )
 
 //go:embed doc.go
@@ -21,7 +21,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "stdmethods",
-	Doc:      analysisutil.MustExtractDoc(doc, "stdmethods"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "stdmethods"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/stdmethods",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stringintconv/string.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stringintconv/string.go
index 7dbff1e4d8d4ee..19c72d2cf938ae 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stringintconv/string.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/stringintconv/string.go
@@ -13,9 +13,9 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/refactor"
 	"golang.org/x/tools/internal/typeparams"
 	"golang.org/x/tools/internal/typesinternal"
 )
@@ -25,7 +25,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "stringintconv",
-	Doc:      analysisutil.MustExtractDoc(doc, "stringintconv"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "stringintconv"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/stringintconv",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
@@ -198,7 +198,7 @@ func run(pass *analysis.Pass) (any, error) {
 		// the type has methods, as some {String,GoString,Format}
 		// may change the behavior of fmt.Sprint.
 		if len(ttypes) == 1 && len(vtypes) == 1 && types.NewMethodSet(V0).Len() == 0 {
-			_, prefix, importEdits := analysisinternal.AddImport(pass.TypesInfo, file, "fmt", "fmt", "Sprint", arg.Pos())
+			prefix, importEdits := refactor.AddImport(pass.TypesInfo, file, "fmt", "fmt", "Sprint", arg.Pos())
 			if types.Identical(T0, types.Typ[types.String]) {
 				// string(x) -> fmt.Sprint(x)
 				addFix("Format the number as a decimal", append(importEdits,
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go
index 360ba0e74d89d3..eba4e56bb0532b 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go
@@ -13,7 +13,6 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
@@ -31,7 +30,7 @@ func init() {
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "testinggoroutine",
-	Doc:      analysisutil.MustExtractDoc(doc, "testinggoroutine"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "testinggoroutine"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/testinggoroutine",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
@@ -40,7 +39,7 @@ var Analyzer = &analysis.Analyzer{
 func run(pass *analysis.Pass) (any, error) {
 	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
 
-	if !analysisinternal.Imports(pass.Pkg, "testing") {
+	if !typesinternal.Imports(pass.Pkg, "testing") {
 		return nil, nil
 	}
 
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/tests/tests.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/tests/tests.go
index d4e9b025324a18..a0ed5ab14e8e14 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/tests/tests.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/tests/tests.go
@@ -15,8 +15,8 @@ import (
 	"unicode/utf8"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 //go:embed doc.go
@@ -24,7 +24,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name: "tests",
-	Doc:  analysisutil.MustExtractDoc(doc, "tests"),
+	Doc:  analysisinternal.MustExtractDoc(doc, "tests"),
 	URL:  "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/tests",
 	Run:  run,
 }
@@ -258,7 +258,7 @@ func isTestingType(typ types.Type, testingType string) bool {
 	if !ok {
 		return false
 	}
-	return analysisinternal.IsTypeNamed(ptr.Elem(), "testing", testingType)
+	return typesinternal.IsTypeNamed(ptr.Elem(), "testing", testingType)
 }
 
 // Validate that fuzz target function's arguments are of accepted types.
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/timeformat/timeformat.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/timeformat/timeformat.go
index 4fdbb2b5415eff..45b6822c17606e 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/timeformat/timeformat.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/timeformat/timeformat.go
@@ -16,10 +16,10 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 const badFormat = "2006-02-01"
@@ -30,7 +30,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "timeformat",
-	Doc:      analysisutil.MustExtractDoc(doc, "timeformat"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "timeformat"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/timeformat",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
@@ -39,7 +39,7 @@ var Analyzer = &analysis.Analyzer{
 func run(pass *analysis.Pass) (any, error) {
 	// Note: (time.Time).Format is a method and can be a typeutil.Callee
 	// without directly importing "time". So we cannot just skip this package
-	// when !analysisutil.Imports(pass.Pkg, "time").
+	// when !analysisinternal.Imports(pass.Pkg, "time").
 	// TODO(taking): Consider using a prepass to collect typeutil.Callees.
 
 	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
@@ -50,8 +50,8 @@ func run(pass *analysis.Pass) (any, error) {
 	inspect.Preorder(nodeFilter, func(n ast.Node) {
 		call := n.(*ast.CallExpr)
 		obj := typeutil.Callee(pass.TypesInfo, call)
-		if !analysisinternal.IsMethodNamed(obj, "time", "Time", "Format") &&
-			!analysisinternal.IsFunctionNamed(obj, "time", "Parse") {
+		if !typesinternal.IsMethodNamed(obj, "time", "Time", "Format") &&
+			!typesinternal.IsFunctionNamed(obj, "time", "Parse") {
 			return
 		}
 		if len(call.Args) > 0 {
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unmarshal/unmarshal.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unmarshal/unmarshal.go
index 26e894bd4000eb..4de48c83930648 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unmarshal/unmarshal.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unmarshal/unmarshal.go
@@ -11,9 +11,9 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
 	"golang.org/x/tools/internal/typesinternal"
 )
 
@@ -22,7 +22,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "unmarshal",
-	Doc:      analysisutil.MustExtractDoc(doc, "unmarshal"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "unmarshal"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/unmarshal",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
@@ -39,7 +39,7 @@ func run(pass *analysis.Pass) (any, error) {
 	// Note: (*"encoding/json".Decoder).Decode, (* "encoding/gob".Decoder).Decode
 	// and (* "encoding/xml".Decoder).Decode are methods and can be a typeutil.Callee
 	// without directly importing their packages. So we cannot just skip this package
-	// when !analysisutil.Imports(pass.Pkg, "encoding/...").
+	// when !analysisinternal.Imports(pass.Pkg, "encoding/...").
 	// TODO(taking): Consider using a prepass to collect typeutil.Callees.
 
 	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unreachable/unreachable.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unreachable/unreachable.go
index 317f034992bb5d..668a33529989d1 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unreachable/unreachable.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unreachable/unreachable.go
@@ -14,8 +14,9 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/refactor"
 )
 
 //go:embed doc.go
@@ -23,7 +24,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:             "unreachable",
-	Doc:              analysisutil.MustExtractDoc(doc, "unreachable"),
+	Doc:              analysisinternal.MustExtractDoc(doc, "unreachable"),
 	URL:              "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/unreachable",
 	Requires:         []*analysis.Analyzer{inspect.Analyzer},
 	RunDespiteErrors: true,
@@ -188,6 +189,11 @@ func (d *deadState) findDead(stmt ast.Stmt) {
 		case *ast.EmptyStmt:
 			// do not warn about unreachable empty statements
 		default:
+			var (
+				inspect    = d.pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+				curStmt, _ = inspect.Root().FindNode(stmt)
+				tokFile    = d.pass.Fset.File(stmt.Pos())
+			)
 			// (This call to pass.Report is a frequent source
 			// of diagnostics beyond EOF in a truncated file;
 			// see #71659.)
@@ -196,11 +202,8 @@ func (d *deadState) findDead(stmt ast.Stmt) {
 				End:     stmt.End(),
 				Message: "unreachable code",
 				SuggestedFixes: []analysis.SuggestedFix{{
-					Message: "Remove",
-					TextEdits: []analysis.TextEdit{{
-						Pos: stmt.Pos(),
-						End: stmt.End(),
-					}},
+					Message:   "Remove",
+					TextEdits: refactor.DeleteStmt(tokFile, curStmt),
 				}},
 			})
 			d.reachable = true // silence error about next statement
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unsafeptr/unsafeptr.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unsafeptr/unsafeptr.go
index 57c6da64ff30e3..24ff723390f597 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unsafeptr/unsafeptr.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unsafeptr/unsafeptr.go
@@ -14,9 +14,9 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 //go:embed doc.go
@@ -24,7 +24,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "unsafeptr",
-	Doc:      analysisutil.MustExtractDoc(doc, "unsafeptr"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "unsafeptr"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/unsafeptr",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
@@ -105,7 +105,7 @@ func isSafeUintptr(info *types.Info, x ast.Expr) bool {
 		}
 		switch sel.Sel.Name {
 		case "Pointer", "UnsafeAddr":
-			if analysisinternal.IsTypeNamed(info.Types[sel.X].Type, "reflect", "Value") {
+			if typesinternal.IsTypeNamed(info.Types[sel.X].Type, "reflect", "Value") {
 				return true
 			}
 		}
@@ -153,5 +153,5 @@ func hasBasicType(info *types.Info, x ast.Expr, kind types.BasicKind) bool {
 
 // isReflectHeader reports whether t is reflect.SliceHeader or reflect.StringHeader.
 func isReflectHeader(t types.Type) bool {
-	return analysisinternal.IsTypeNamed(t, "reflect", "SliceHeader", "StringHeader")
+	return typesinternal.IsTypeNamed(t, "reflect", "SliceHeader", "StringHeader")
 }
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unusedresult/unusedresult.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unusedresult/unusedresult.go
index ed4cf7ae0be35b..57ad4f0769924c 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unusedresult/unusedresult.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/unusedresult/unusedresult.go
@@ -23,7 +23,6 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
@@ -34,7 +33,7 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "unusedresult",
-	Doc:      analysisutil.MustExtractDoc(doc, "unusedresult"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "unusedresult"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/unusedresult",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/waitgroup/waitgroup.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/waitgroup/waitgroup.go
index 14c6986eabab3b..88e4cc8677691e 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/waitgroup/waitgroup.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/waitgroup/waitgroup.go
@@ -13,10 +13,10 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
-	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/go/types/typeutil"
 	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/typesinternal"
 )
 
 //go:embed doc.go
@@ -24,14 +24,14 @@ var doc string
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "waitgroup",
-	Doc:      analysisutil.MustExtractDoc(doc, "waitgroup"),
+	Doc:      analysisinternal.MustExtractDoc(doc, "waitgroup"),
 	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/waitgroup",
 	Requires: []*analysis.Analyzer{inspect.Analyzer},
 	Run:      run,
 }
 
 func run(pass *analysis.Pass) (any, error) {
-	if !analysisinternal.Imports(pass.Pkg, "sync") {
+	if !typesinternal.Imports(pass.Pkg, "sync") {
 		return nil, nil // doesn't directly import sync
 	}
 
@@ -44,7 +44,7 @@ func run(pass *analysis.Pass) (any, error) {
 		if push {
 			call := n.(*ast.CallExpr)
 			obj := typeutil.Callee(pass.TypesInfo, call)
-			if analysisinternal.IsMethodNamed(obj, "sync", "WaitGroup", "Add") &&
+			if typesinternal.IsMethodNamed(obj, "sync", "WaitGroup", "Add") &&
 				hasSuffix(stack, wantSuffix) &&
 				backindex(stack, 1) == backindex(stack, 2).(*ast.BlockStmt).List[0] { // ExprStmt must be Block's first stmt
 
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
index 7b805b882bf2df..b407bc7791547f 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
@@ -75,7 +75,6 @@ type Config struct {
 	VetxOutput                string            // where to write file of fact information
 	Stdout                    string            // write stdout (e.g. JSON, unified diff) to this file
 	SucceedOnTypecheckFailure bool              // obsolete awful hack; see #18395 and below
-	WarnDiagnostics           bool              // printing diagnostics should not cause a non-zero exit
 }
 
 // Main is the main function of a vet-like analysis tool that must be
@@ -87,18 +86,9 @@ type Config struct {
 //	-V=full         describe executable for build caching
 //	foo.cfg         perform separate modular analyze on the single
 //	                unit described by a JSON config file foo.cfg.
-//
-// Also, subject to approval of proposal #71859:
-//
 //	-fix		don't print each diagnostic, apply its first fix
 //	-diff		don't apply a fix, print the diff (requires -fix)
-//
-// Additionally, the environment variable GOVET has the value "vet" or
-// "fix" depending on whether the command is being invoked by "go vet",
-// to report diagnostics, or "go fix", to apply fixes. This is
-// necessary so that callers of Main can select their analyzer suite
-// before flag parsing. (Vet analyzers must report real code problems,
-// whereas Fix analyzers may fix non-problems such as style issues.)
+//	-json		print diagnostics and fixes in JSON form
 func Main(analyzers ...*analysis.Analyzer) {
 	progname := filepath.Base(os.Args[0])
 	log.SetFlags(0)
@@ -163,7 +153,7 @@ func Run(configFile string, analyzers []*analysis.Analyzer) {
 
 	// In VetxOnly mode, the analysis is run only for facts.
 	if !cfg.VetxOnly {
-		code = processResults(fset, cfg.ID, results, cfg.WarnDiagnostics)
+		code = processResults(fset, cfg.ID, results)
 	}
 
 	os.Exit(code)
@@ -187,7 +177,7 @@ func readConfig(filename string) (*Config, error) {
 	return cfg, nil
 }
 
-func processResults(fset *token.FileSet, id string, results []result, warnDiagnostics bool) (exit int) {
+func processResults(fset *token.FileSet, id string, results []result) (exit int) {
 	if analysisflags.Fix {
 		// Don't print the diagnostics,
 		// but apply all fixes from the root actions.
@@ -236,9 +226,7 @@ func processResults(fset *token.FileSet, id string, results []result, warnDiagno
 		for _, res := range results {
 			for _, diag := range res.diagnostics {
 				analysisflags.PrintPlain(os.Stderr, fset, analysisflags.Context, diag)
-				if !warnDiagnostics {
-					exit = 1
-				}
+				exit = 1
 			}
 		}
 	}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/analysis.go b/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/analysis.go
index cea89d34dac45b..970d7507f02d0a 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/analysis.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/analysis.go
@@ -2,166 +2,39 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package analysisinternal provides gopls' internal analyses with a
-// number of helper functions that operate on typed syntax trees.
+// Package analysisinternal provides helper functions for use in both
+// the analysis drivers in go/analysis and gopls, and in various
+// analyzers.
+//
+// TODO(adonovan): this is not ideal as it may lead to unnecessary
+// dependencies between drivers and analyzers. Split into analyzerlib
+// and driverlib?
 package analysisinternal
 
 import (
-	"bytes"
 	"cmp"
 	"fmt"
-	"go/ast"
-	"go/printer"
-	"go/scanner"
 	"go/token"
-	"go/types"
-	"iter"
-	pathpkg "path"
+	"os"
 	"slices"
-	"strings"
 
 	"golang.org/x/tools/go/analysis"
-	"golang.org/x/tools/go/ast/inspector"
-	"golang.org/x/tools/internal/moreiters"
-	"golang.org/x/tools/internal/typesinternal"
 )
 
-// Deprecated: this heuristic is ill-defined.
-// TODO(adonovan): move to sole use in gopls/internal/cache.
-func TypeErrorEndPos(fset *token.FileSet, src []byte, start token.Pos) token.Pos {
-	// Get the end position for the type error.
-	file := fset.File(start)
-	if file == nil {
-		return start
-	}
-	if offset := file.PositionFor(start, false).Offset; offset > len(src) {
-		return start
-	} else {
-		src = src[offset:]
-	}
-
-	// Attempt to find a reasonable end position for the type error.
-	//
-	// TODO(rfindley): the heuristic implemented here is unclear. It looks like
-	// it seeks the end of the primary operand starting at start, but that is not
-	// quite implemented (for example, given a func literal this heuristic will
-	// return the range of the func keyword).
-	//
-	// We should formalize this heuristic, or deprecate it by finally proposing
-	// to add end position to all type checker errors.
-	//
-	// Nevertheless, ensure that the end position at least spans the current
-	// token at the cursor (this was golang/go#69505).
-	end := start
-	{
-		var s scanner.Scanner
-		fset := token.NewFileSet()
-		f := fset.AddFile("", fset.Base(), len(src))
-		s.Init(f, src, nil /* no error handler */, scanner.ScanComments)
-		pos, tok, lit := s.Scan()
-		if tok != token.SEMICOLON && token.Pos(f.Base()) <= pos && pos <= token.Pos(f.Base()+f.Size()) {
-			off := file.Offset(pos) + len(lit)
-			src = src[off:]
-			end += token.Pos(off)
-		}
+// ReadFile reads a file and adds it to the FileSet in pass
+// so that we can report errors against it using lineStart.
+func ReadFile(pass *analysis.Pass, filename string) ([]byte, *token.File, error) {
+	readFile := pass.ReadFile
+	if readFile == nil {
+		readFile = os.ReadFile
 	}
-
-	// Look for bytes that might terminate the current operand. See note above:
-	// this is imprecise.
-	if width := bytes.IndexAny(src, " \n,():;[]+-*/"); width > 0 {
-		end += token.Pos(width)
+	content, err := readFile(filename)
+	if err != nil {
+		return nil, nil, err
 	}
-	return end
-}
-
-// MatchingIdents finds the names of all identifiers in 'node' that match any of the given types.
-// 'pos' represents the position at which the identifiers may be inserted. 'pos' must be within
-// the scope of each of identifier we select. Otherwise, we will insert a variable at 'pos' that
-// is unrecognized.
-func MatchingIdents(typs []types.Type, node ast.Node, pos token.Pos, info *types.Info, pkg *types.Package) map[types.Type][]string {
-
-	// Initialize matches to contain the variable types we are searching for.
-	matches := make(map[types.Type][]string)
-	for _, typ := range typs {
-		if typ == nil {
-			continue // TODO(adonovan): is this reachable?
-		}
-		matches[typ] = nil // create entry
-	}
-
-	seen := map[types.Object]struct{}{}
-	ast.Inspect(node, func(n ast.Node) bool {
-		if n == nil {
-			return false
-		}
-		// Prevent circular definitions. If 'pos' is within an assignment statement, do not
-		// allow any identifiers in that assignment statement to be selected. Otherwise,
-		// we could do the following, where 'x' satisfies the type of 'f0':
-		//
-		// x := fakeStruct{f0: x}
-		//
-		if assign, ok := n.(*ast.AssignStmt); ok && pos > assign.Pos() && pos <= assign.End() {
-			return false
-		}
-		if n.End() > pos {
-			return n.Pos() <= pos
-		}
-		ident, ok := n.(*ast.Ident)
-		if !ok || ident.Name == "_" {
-			return true
-		}
-		obj := info.Defs[ident]
-		if obj == nil || obj.Type() == nil {
-			return true
-		}
-		if _, ok := obj.(*types.TypeName); ok {
-			return true
-		}
-		// Prevent duplicates in matches' values.
-		if _, ok = seen[obj]; ok {
-			return true
-		}
-		seen[obj] = struct{}{}
-		// Find the scope for the given position. Then, check whether the object
-		// exists within the scope.
-		innerScope := pkg.Scope().Innermost(pos)
-		if innerScope == nil {
-			return true
-		}
-		_, foundObj := innerScope.LookupParent(ident.Name, pos)
-		if foundObj != obj {
-			return true
-		}
-		// The object must match one of the types that we are searching for.
-		// TODO(adonovan): opt: use typeutil.Map?
-		if names, ok := matches[obj.Type()]; ok {
-			matches[obj.Type()] = append(names, ident.Name)
-		} else {
-			// If the object type does not exactly match
-			// any of the target types, greedily find the first
-			// target type that the object type can satisfy.
-			for typ := range matches {
-				if equivalentTypes(obj.Type(), typ) {
-					matches[typ] = append(matches[typ], ident.Name)
-				}
-			}
-		}
-		return true
-	})
-	return matches
-}
-
-func equivalentTypes(want, got types.Type) bool {
-	if types.Identical(want, got) {
-		return true
-	}
-	// Code segment to help check for untyped equality from (golang/go#32146).
-	if rhs, ok := want.(*types.Basic); ok && rhs.Info()&types.IsUntyped > 0 {
-		if lhs, ok := got.Underlying().(*types.Basic); ok {
-			return rhs.Info()&types.IsConstType == lhs.Info()&types.IsConstType
-		}
-	}
-	return types.AssignableTo(want, got)
+	tf := pass.Fset.AddFile(filename, -1, len(content))
+	tf.SetLinesForContent(content)
+	return content, tf, nil
 }
 
 // A ReadFileFunc is a function that returns the
@@ -193,207 +66,6 @@ func CheckReadable(pass *analysis.Pass, filename string) error {
 	return fmt.Errorf("Pass.ReadFile: %s is not among OtherFiles, IgnoredFiles, or names of Files", filename)
 }
 
-// AddImport checks whether this file already imports pkgpath and that
-// the import is in scope at pos. If so, it returns the name under
-// which it was imported and no edits. Otherwise, it adds a new import
-// of pkgpath, using a name derived from the preferred name, and
-// returns the chosen name, a prefix to be concatenated with member to
-// form a qualified name, and the edit for the new import.
-//
-// The member argument indicates the name of the desired symbol within
-// the imported package. This is needed in the case when the existing
-// import is a dot import, because then it is possible that the
-// desired symbol is shadowed by other declarations in the current
-// package. If member is not shadowed at pos, AddImport returns (".",
-// "", nil). (AddImport accepts the caller's implicit claim that the
-// imported package declares member.)
-//
-// Use a preferredName of "_" to request a blank import;
-// member is ignored in this case.
-//
-// It does not mutate its arguments.
-func AddImport(info *types.Info, file *ast.File, preferredName, pkgpath, member string, pos token.Pos) (name, prefix string, newImport []analysis.TextEdit) {
-	// Find innermost enclosing lexical block.
-	scope := info.Scopes[file].Innermost(pos)
-	if scope == nil {
-		panic("no enclosing lexical block")
-	}
-
-	// Is there an existing import of this package?
-	// If so, are we in its scope? (not shadowed)
-	for _, spec := range file.Imports {
-		pkgname := info.PkgNameOf(spec)
-		if pkgname != nil && pkgname.Imported().Path() == pkgpath {
-			name = pkgname.Name()
-			if preferredName == "_" {
-				// Request for blank import; any existing import will do.
-				return name, "", nil
-			}
-			if name == "." {
-				// The scope of ident must be the file scope.
-				if s, _ := scope.LookupParent(member, pos); s == info.Scopes[file] {
-					return name, "", nil
-				}
-			} else if _, obj := scope.LookupParent(name, pos); obj == pkgname {
-				return name, name + ".", nil
-			}
-		}
-	}
-
-	// We must add a new import.
-
-	// Ensure we have a fresh name.
-	newName := preferredName
-	if preferredName != "_" {
-		newName = FreshName(scope, pos, preferredName)
-	}
-
-	// Create a new import declaration either before the first existing
-	// declaration (which must exist), including its comments; or
-	// inside the declaration, if it is an import group.
-	//
-	// Use a renaming import whenever the preferred name is not
-	// available, or the chosen name does not match the last
-	// segment of its path.
-	newText := fmt.Sprintf("%q", pkgpath)
-	if newName != preferredName || newName != pathpkg.Base(pkgpath) {
-		newText = fmt.Sprintf("%s %q", newName, pkgpath)
-	}
-
-	decl0 := file.Decls[0]
-	var before ast.Node = decl0
-	switch decl0 := decl0.(type) {
-	case *ast.GenDecl:
-		if decl0.Doc != nil {
-			before = decl0.Doc
-		}
-	case *ast.FuncDecl:
-		if decl0.Doc != nil {
-			before = decl0.Doc
-		}
-	}
-	if gd, ok := before.(*ast.GenDecl); ok && gd.Tok == token.IMPORT && gd.Rparen.IsValid() {
-		// Have existing grouped import ( ... ) decl.
-		if IsStdPackage(pkgpath) && len(gd.Specs) > 0 {
-			// Add spec for a std package before
-			// first existing spec, followed by
-			// a blank line if the next one is non-std.
-			first := gd.Specs[0].(*ast.ImportSpec)
-			pos = first.Pos()
-			if !IsStdPackage(first.Path.Value) {
-				newText += "\n"
-			}
-			newText += "\n\t"
-		} else {
-			// Add spec at end of group.
-			pos = gd.Rparen
-			newText = "\t" + newText + "\n"
-		}
-	} else {
-		// No import decl, or non-grouped import.
-		// Add a new import decl before first decl.
-		// (gofmt will merge multiple import decls.)
-		pos = before.Pos()
-		newText = "import " + newText + "\n\n"
-	}
-	return newName, newName + ".", []analysis.TextEdit{{
-		Pos:     pos,
-		End:     pos,
-		NewText: []byte(newText),
-	}}
-}
-
-// FreshName returns the name of an identifier that is undefined
-// at the specified position, based on the preferred name.
-func FreshName(scope *types.Scope, pos token.Pos, preferred string) string {
-	newName := preferred
-	for i := 0; ; i++ {
-		if _, obj := scope.LookupParent(newName, pos); obj == nil {
-			break // fresh
-		}
-		newName = fmt.Sprintf("%s%d", preferred, i)
-	}
-	return newName
-}
-
-// Format returns a string representation of the node n.
-func Format(fset *token.FileSet, n ast.Node) string {
-	var buf strings.Builder
-	printer.Fprint(&buf, fset, n) // ignore errors
-	return buf.String()
-}
-
-// Imports returns true if path is imported by pkg.
-func Imports(pkg *types.Package, path string) bool {
-	for _, imp := range pkg.Imports() {
-		if imp.Path() == path {
-			return true
-		}
-	}
-	return false
-}
-
-// IsTypeNamed reports whether t is (or is an alias for) a
-// package-level defined type with the given package path and one of
-// the given names. It returns false if t is nil.
-//
-// This function avoids allocating the concatenation of "pkg.Name",
-// which is important for the performance of syntax matching.
-func IsTypeNamed(t types.Type, pkgPath string, names ...string) bool {
-	if named, ok := types.Unalias(t).(*types.Named); ok {
-		tname := named.Obj()
-		return tname != nil &&
-			typesinternal.IsPackageLevel(tname) &&
-			tname.Pkg().Path() == pkgPath &&
-			slices.Contains(names, tname.Name())
-	}
-	return false
-}
-
-// IsPointerToNamed reports whether t is (or is an alias for) a pointer to a
-// package-level defined type with the given package path and one of the given
-// names. It returns false if t is not a pointer type.
-func IsPointerToNamed(t types.Type, pkgPath string, names ...string) bool {
-	r := typesinternal.Unpointer(t)
-	if r == t {
-		return false
-	}
-	return IsTypeNamed(r, pkgPath, names...)
-}
-
-// IsFunctionNamed reports whether obj is a package-level function
-// defined in the given package and has one of the given names.
-// It returns false if obj is nil.
-//
-// This function avoids allocating the concatenation of "pkg.Name",
-// which is important for the performance of syntax matching.
-func IsFunctionNamed(obj types.Object, pkgPath string, names ...string) bool {
-	f, ok := obj.(*types.Func)
-	return ok &&
-		typesinternal.IsPackageLevel(obj) &&
-		f.Pkg().Path() == pkgPath &&
-		f.Type().(*types.Signature).Recv() == nil &&
-		slices.Contains(names, f.Name())
-}
-
-// IsMethodNamed reports whether obj is a method defined on a
-// package-level type with the given package and type name, and has
-// one of the given names. It returns false if obj is nil.
-//
-// This function avoids allocating the concatenation of "pkg.TypeName.Name",
-// which is important for the performance of syntax matching.
-func IsMethodNamed(obj types.Object, pkgPath string, typeName string, names ...string) bool {
-	if fn, ok := obj.(*types.Func); ok {
-		if recv := fn.Type().(*types.Signature).Recv(); recv != nil {
-			_, T := typesinternal.ReceiverNamed(recv)
-			return T != nil &&
-				IsTypeNamed(T, pkgPath, typeName) &&
-				slices.Contains(names, fn.Name())
-		}
-	}
-	return false
-}
-
 // ValidateFixes validates the set of fixes for a single diagnostic.
 // Any error indicates a bug in the originating analyzer.
 //
@@ -496,172 +168,6 @@ func validateFix(fset *token.FileSet, fix *analysis.SuggestedFix) error {
 	return nil
 }
 
-// CanImport reports whether one package is allowed to import another.
-//
-// TODO(adonovan): allow customization of the accessibility relation
-// (e.g. for Bazel).
-func CanImport(from, to string) bool {
-	// TODO(adonovan): better segment hygiene.
-	if to == "internal" || strings.HasPrefix(to, "internal/") {
-		// Special case: only std packages may import internal/...
-		// We can't reliably know whether we're in std, so we
-		// use a heuristic on the first segment.
-		first, _, _ := strings.Cut(from, "/")
-		if strings.Contains(first, ".") {
-			return false // example.com/foo ∉ std
-		}
-		if first == "testdata" {
-			return false // testdata/foo ∉ std
-		}
-	}
-	if strings.HasSuffix(to, "/internal") {
-		return strings.HasPrefix(from, to[:len(to)-len("/internal")])
-	}
-	if i := strings.LastIndex(to, "/internal/"); i >= 0 {
-		return strings.HasPrefix(from, to[:i])
-	}
-	return true
-}
-
-// DeleteStmt returns the edits to remove the [ast.Stmt] identified by
-// curStmt, if it is contained within a BlockStmt, CaseClause,
-// CommClause, or is the STMT in switch STMT; ... {...}. It returns nil otherwise.
-func DeleteStmt(fset *token.FileSet, curStmt inspector.Cursor) []analysis.TextEdit {
-	stmt := curStmt.Node().(ast.Stmt)
-	// if the stmt is on a line by itself delete the whole line
-	// otherwise just delete the statement.
-
-	// this logic would be a lot simpler with the file contents, and somewhat simpler
-	// if the cursors included the comments.
-
-	tokFile := fset.File(stmt.Pos())
-	lineOf := tokFile.Line
-	stmtStartLine, stmtEndLine := lineOf(stmt.Pos()), lineOf(stmt.End())
-
-	var from, to token.Pos
-	// bounds of adjacent syntax/comments on same line, if any
-	limits := func(left, right token.Pos) {
-		if lineOf(left) == stmtStartLine {
-			from = left
-		}
-		if lineOf(right) == stmtEndLine {
-			to = right
-		}
-	}
-	// TODO(pjw): there are other places a statement might be removed:
-	// IfStmt = "if" [ SimpleStmt ";" ] Expression Block [ "else" ( IfStmt | Block ) ] .
-	// (removing the blocks requires more rewriting than this routine would do)
-	// CommCase   = "case" ( SendStmt | RecvStmt ) | "default" .
-	// (removing the stmt requires more rewriting, and it's unclear what the user means)
-	switch parent := curStmt.Parent().Node().(type) {
-	case *ast.SwitchStmt:
-		limits(parent.Switch, parent.Body.Lbrace)
-	case *ast.TypeSwitchStmt:
-		limits(parent.Switch, parent.Body.Lbrace)
-		if parent.Assign == stmt {
-			return nil // don't let the user break the type switch
-		}
-	case *ast.BlockStmt:
-		limits(parent.Lbrace, parent.Rbrace)
-	case *ast.CommClause:
-		limits(parent.Colon, curStmt.Parent().Parent().Node().(*ast.BlockStmt).Rbrace)
-		if parent.Comm == stmt {
-			return nil // maybe the user meant to remove the entire CommClause?
-		}
-	case *ast.CaseClause:
-		limits(parent.Colon, curStmt.Parent().Parent().Node().(*ast.BlockStmt).Rbrace)
-	case *ast.ForStmt:
-		limits(parent.For, parent.Body.Lbrace)
-
-	default:
-		return nil // not one of ours
-	}
-
-	if prev, found := curStmt.PrevSibling(); found && lineOf(prev.Node().End()) == stmtStartLine {
-		from = prev.Node().End() // preceding statement ends on same line
-	}
-	if next, found := curStmt.NextSibling(); found && lineOf(next.Node().Pos()) == stmtEndLine {
-		to = next.Node().Pos() // following statement begins on same line
-	}
-	// and now for the comments
-Outer:
-	for _, cg := range enclosingFile(curStmt).Comments {
-		for _, co := range cg.List {
-			if lineOf(co.End()) < stmtStartLine {
-				continue
-			} else if lineOf(co.Pos()) > stmtEndLine {
-				break Outer // no more are possible
-			}
-			if lineOf(co.End()) == stmtStartLine && co.End() < stmt.Pos() {
-				if !from.IsValid() || co.End() > from {
-					from = co.End()
-					continue // maybe there are more
-				}
-			}
-			if lineOf(co.Pos()) == stmtEndLine && co.Pos() > stmt.End() {
-				if !to.IsValid() || co.Pos() < to {
-					to = co.Pos()
-					continue // maybe there are more
-				}
-			}
-		}
-	}
-	// if either from or to is valid, just remove the statement
-	// otherwise remove the line
-	edit := analysis.TextEdit{Pos: stmt.Pos(), End: stmt.End()}
-	if from.IsValid() || to.IsValid() {
-		// remove just the statement.
-		// we can't tell if there is a ; or whitespace right after the statement
-		// ideally we'd like to remove the former and leave the latter
-		// (if gofmt has run, there likely won't be a ;)
-		// In type switches we know there's a semicolon somewhere after the statement,
-		// but the extra work for this special case is not worth it, as gofmt will fix it.
-		return []analysis.TextEdit{edit}
-	}
-	// remove the whole line
-	for lineOf(edit.Pos) == stmtStartLine {
-		edit.Pos--
-	}
-	edit.Pos++ // get back tostmtStartLine
-	for lineOf(edit.End) == stmtEndLine {
-		edit.End++
-	}
-	return []analysis.TextEdit{edit}
-}
-
-// Comments returns an iterator over the comments overlapping the specified interval.
-func Comments(file *ast.File, start, end token.Pos) iter.Seq[*ast.Comment] {
-	// TODO(adonovan): optimize use binary O(log n) instead of linear O(n) search.
-	return func(yield func(*ast.Comment) bool) {
-		for _, cg := range file.Comments {
-			for _, co := range cg.List {
-				if co.Pos() > end {
-					return
-				}
-				if co.End() < start {
-					continue
-				}
-
-				if !yield(co) {
-					return
-				}
-			}
-		}
-	}
-}
-
-// IsStdPackage reports whether the specified package path belongs to a
-// package in the standard library (including internal dependencies).
-func IsStdPackage(path string) bool {
-	// A standard package has no dot in its first segment.
-	// (It may yet have a dot, e.g. "vendor/golang.org/x/foo".)
-	slash := strings.IndexByte(path, '/')
-	if slash < 0 {
-		slash = len(path)
-	}
-	return !strings.Contains(path[:slash], ".") && path != "testdata"
-}
-
 // Range returns an [analysis.Range] for the specified start and end positions.
 func Range(pos, end token.Pos) analysis.Range {
 	return tokenRange{pos, end}
@@ -672,9 +178,3 @@ type tokenRange struct{ StartPos, EndPos token.Pos }
 
 func (r tokenRange) Pos() token.Pos { return r.StartPos }
 func (r tokenRange) End() token.Pos { return r.EndPos }
-
-// enclosingFile returns the syntax tree for the file enclosing c.
-func enclosingFile(c inspector.Cursor) *ast.File {
-	c, _ = moreiters.First(c.Enclosing((*ast.File)(nil)))
-	return c.Node().(*ast.File)
-}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/extractdoc.go b/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/extractdoc.go
index bfb5900f1b3195..c6cdf5997e2194 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/extractdoc.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/extractdoc.go
@@ -35,7 +35,7 @@ import (
 //
 //	var Analyzer = &analysis.Analyzer{
 //		Name:             "halting",
-//		Doc:              analysisutil.MustExtractDoc(doc, "halting"),
+//		Doc:              analysisinternal.MustExtractDoc(doc, "halting"),
 //		...
 //	}
 func MustExtractDoc(content, name string) string {
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/astutil/comment.go b/src/cmd/vendor/golang.org/x/tools/internal/astutil/comment.go
index c3a256c987cbc3..7e52aeaaac590a 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/astutil/comment.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/astutil/comment.go
@@ -7,6 +7,7 @@ package astutil
 import (
 	"go/ast"
 	"go/token"
+	"iter"
 	"strings"
 )
 
@@ -111,3 +112,24 @@ func Directives(g *ast.CommentGroup) (res []*Directive) {
 	}
 	return
 }
+
+// Comments returns an iterator over the comments overlapping the specified interval.
+func Comments(file *ast.File, start, end token.Pos) iter.Seq[*ast.Comment] {
+	// TODO(adonovan): optimize use binary O(log n) instead of linear O(n) search.
+	return func(yield func(*ast.Comment) bool) {
+		for _, cg := range file.Comments {
+			for _, co := range cg.List {
+				if co.Pos() > end {
+					return
+				}
+				if co.End() < start {
+					continue
+				}
+
+				if !yield(co) {
+					return
+				}
+			}
+		}
+	}
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/astutil/equal.go b/src/cmd/vendor/golang.org/x/tools/internal/astutil/equal.go
index c945de02d4a130..210f392387b426 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/astutil/equal.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/astutil/equal.go
@@ -26,6 +26,14 @@ func Equal(x, y ast.Node, identical func(x, y *ast.Ident) bool) bool {
 	return equal(reflect.ValueOf(x), reflect.ValueOf(y), identical)
 }
 
+// EqualSyntax reports whether x and y are equal.
+// Identifiers are considered equal if they are spelled the same.
+// Comments are ignored.
+func EqualSyntax(x, y ast.Expr) bool {
+	sameName := func(x, y *ast.Ident) bool { return x.Name == y.Name }
+	return Equal(x, y, sameName)
+}
+
 func equal(x, y reflect.Value, identical func(x, y *ast.Ident) bool) bool {
 	// Ensure types are the same
 	if x.Type() != y.Type() {
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/astutil/util.go b/src/cmd/vendor/golang.org/x/tools/internal/astutil/util.go
index 14189155e4e895..a1c09835041bf0 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/astutil/util.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/astutil/util.go
@@ -6,7 +6,13 @@ package astutil
 
 import (
 	"go/ast"
+	"go/printer"
 	"go/token"
+	"strings"
+
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/moreiters"
 )
 
 // PreorderStack traverses the tree rooted at root,
@@ -67,3 +73,47 @@ func NodeContains(n ast.Node, pos token.Pos) bool {
 	}
 	return start <= pos && pos <= end
 }
+
+// IsChildOf reports whether cur.ParentEdge is ek.
+//
+// TODO(adonovan): promote to a method of Cursor.
+func IsChildOf(cur inspector.Cursor, ek edge.Kind) bool {
+	got, _ := cur.ParentEdge()
+	return got == ek
+}
+
+// EnclosingFile returns the syntax tree for the file enclosing c.
+//
+// TODO(adonovan): promote this to a method of Cursor.
+func EnclosingFile(c inspector.Cursor) *ast.File {
+	c, _ = moreiters.First(c.Enclosing((*ast.File)(nil)))
+	return c.Node().(*ast.File)
+}
+
+// DocComment returns the doc comment for a node, if any.
+func DocComment(n ast.Node) *ast.CommentGroup {
+	switch n := n.(type) {
+	case *ast.FuncDecl:
+		return n.Doc
+	case *ast.GenDecl:
+		return n.Doc
+	case *ast.ValueSpec:
+		return n.Doc
+	case *ast.TypeSpec:
+		return n.Doc
+	case *ast.File:
+		return n.Doc
+	case *ast.ImportSpec:
+		return n.Doc
+	case *ast.Field:
+		return n.Doc
+	}
+	return nil
+}
+
+// Format returns a string representation of the node n.
+func Format(fset *token.FileSet, n ast.Node) string {
+	var buf strings.Builder
+	printer.Fprint(&buf, fset, n) // ignore errors
+	return buf.String()
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/diff/lcs/old.go b/src/cmd/vendor/golang.org/x/tools/internal/diff/lcs/old.go
index 4c346706a7566c..7b7c5cc677beb4 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/diff/lcs/old.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/diff/lcs/old.go
@@ -378,10 +378,7 @@ func (e *editGraph) twoDone(df, db int) (int, bool) {
 		return 0, false // diagonals cannot overlap
 	}
 	kmin := max(-df, -db+e.delta)
-	kmax := db + e.delta
-	if df < kmax {
-		kmax = df
-	}
+	kmax := min(df, db+e.delta)
 	for k := kmin; k <= kmax; k += 2 {
 		x := e.vf.get(df, k)
 		u := e.vb.get(db, k-e.delta)
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/diff/lcs/sequence.go b/src/cmd/vendor/golang.org/x/tools/internal/diff/lcs/sequence.go
index 2d72d2630435b8..811bb216ea2f24 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/diff/lcs/sequence.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/diff/lcs/sequence.go
@@ -103,11 +103,3 @@ func commonSuffixLenString(a, b string) int {
 	}
 	return i
 }
-
-func min(x, y int) int {
-	if x < y {
-		return x
-	} else {
-		return y
-	}
-}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/packagepath/packagepath.go b/src/cmd/vendor/golang.org/x/tools/internal/packagepath/packagepath.go
new file mode 100644
index 00000000000000..fa39a13f9eae51
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/packagepath/packagepath.go
@@ -0,0 +1,49 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package packagepath provides metadata operations on package path
+// strings.
+package packagepath
+
+// (This package should not depend on go/ast.)
+import "strings"
+
+// CanImport reports whether one package is allowed to import another.
+//
+// TODO(adonovan): allow customization of the accessibility relation
+// (e.g. for Bazel).
+func CanImport(from, to string) bool {
+	// TODO(adonovan): better segment hygiene.
+	if to == "internal" || strings.HasPrefix(to, "internal/") {
+		// Special case: only std packages may import internal/...
+		// We can't reliably know whether we're in std, so we
+		// use a heuristic on the first segment.
+		first, _, _ := strings.Cut(from, "/")
+		if strings.Contains(first, ".") {
+			return false // example.com/foo ∉ std
+		}
+		if first == "testdata" {
+			return false // testdata/foo ∉ std
+		}
+	}
+	if strings.HasSuffix(to, "/internal") {
+		return strings.HasPrefix(from, to[:len(to)-len("/internal")])
+	}
+	if i := strings.LastIndex(to, "/internal/"); i >= 0 {
+		return strings.HasPrefix(from, to[:i])
+	}
+	return true
+}
+
+// IsStdPackage reports whether the specified package path belongs to a
+// package in the standard library (including internal dependencies).
+func IsStdPackage(path string) bool {
+	// A standard package has no dot in its first segment.
+	// (It may yet have a dot, e.g. "vendor/golang.org/x/foo".)
+	slash := strings.IndexByte(path, '/')
+	if slash < 0 {
+		slash = len(path)
+	}
+	return !strings.Contains(path[:slash], ".") && path != "testdata"
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/delete.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/delete.go
new file mode 100644
index 00000000000000..6df01d8ef9c779
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/delete.go
@@ -0,0 +1,484 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package refactor
+
+// This file defines operations for computing deletion edits.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"slices"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+// DeleteVar returns edits to delete the declaration of a variable or
+// constant whose defining identifier is curId.
+//
+// It handles variants including:
+// - GenDecl > ValueSpec versus AssignStmt;
+// - RHS expression has effects, or not;
+// - entire statement/declaration may be eliminated;
+// and removes associated comments.
+//
+// If it cannot make the necessary edits, such as for a function
+// parameter or result, it returns nil.
+func DeleteVar(tokFile *token.File, info *types.Info, curId inspector.Cursor) []analysis.TextEdit {
+	switch ek, _ := curId.ParentEdge(); ek {
+	case edge.ValueSpec_Names:
+		return deleteVarFromValueSpec(tokFile, info, curId)
+
+	case edge.AssignStmt_Lhs:
+		return deleteVarFromAssignStmt(tokFile, info, curId)
+	}
+
+	// e.g. function receiver, parameter, or result,
+	// or "switch v := expr.(T) {}" (which has no object).
+	return nil
+}
+
+// deleteVarFromValueSpec returns edits to delete the declaration of a
+// variable or constant within a ValueSpec.
+//
+// Precondition: curId is Ident beneath ValueSpec.Names beneath GenDecl.
+//
+// See also [deleteVarFromAssignStmt], which has parallel structure.
+func deleteVarFromValueSpec(tokFile *token.File, info *types.Info, curIdent inspector.Cursor) []analysis.TextEdit {
+	var (
+		id      = curIdent.Node().(*ast.Ident)
+		curSpec = curIdent.Parent()
+		spec    = curSpec.Node().(*ast.ValueSpec)
+	)
+
+	declaresOtherNames := slices.ContainsFunc(spec.Names, func(name *ast.Ident) bool {
+		return name != id && name.Name != "_"
+	})
+	noRHSEffects := !slices.ContainsFunc(spec.Values, func(rhs ast.Expr) bool {
+		return !typesinternal.NoEffects(info, rhs)
+	})
+	if !declaresOtherNames && noRHSEffects {
+		// The spec is no longer needed, either to declare
+		// other variables, or for its side effects.
+		return DeleteSpec(tokFile, curSpec)
+	}
+
+	// The spec is still needed, either for
+	// at least one LHS, or for effects on RHS.
+	// Blank out or delete just one LHS.
+
+	_, index := curIdent.ParentEdge() // index of LHS within ValueSpec.Names
+
+	// If there is no RHS, we can delete the LHS.
+	if len(spec.Values) == 0 {
+		var pos, end token.Pos
+		if index == len(spec.Names)-1 {
+			// Delete final name.
+			//
+			// var _, lhs1 T
+			//      ------
+			pos = spec.Names[index-1].End()
+			end = spec.Names[index].End()
+		} else {
+			// Delete non-final name.
+			//
+			// var lhs0, _ T
+			//     ------
+			pos = spec.Names[index].Pos()
+			end = spec.Names[index+1].Pos()
+		}
+		return []analysis.TextEdit{{
+			Pos: pos,
+			End: end,
+		}}
+	}
+
+	// If the assignment is n:n and the RHS has no effects,
+	// we can delete the LHS and its corresponding RHS.
+	if len(spec.Names) == len(spec.Values) &&
+		typesinternal.NoEffects(info, spec.Values[index]) {
+
+		if index == len(spec.Names)-1 {
+			// Delete final items.
+			//
+			// var _, lhs1 = rhs0, rhs1
+			//      ------       ------
+			return []analysis.TextEdit{
+				{
+					Pos: spec.Names[index-1].End(),
+					End: spec.Names[index].End(),
+				},
+				{
+					Pos: spec.Values[index-1].End(),
+					End: spec.Values[index].End(),
+				},
+			}
+		} else {
+			// Delete non-final items.
+			//
+			// var lhs0, _ = rhs0, rhs1
+			//     ------    ------
+			return []analysis.TextEdit{
+				{
+					Pos: spec.Names[index].Pos(),
+					End: spec.Names[index+1].Pos(),
+				},
+				{
+					Pos: spec.Values[index].Pos(),
+					End: spec.Values[index+1].Pos(),
+				},
+			}
+		}
+	}
+
+	// We cannot delete the RHS.
+	// Blank out the LHS.
+	return []analysis.TextEdit{{
+		Pos:     id.Pos(),
+		End:     id.End(),
+		NewText: []byte("_"),
+	}}
+}
+
+// Precondition: curId is Ident beneath AssignStmt.Lhs.
+//
+// See also [deleteVarFromValueSpec], which has parallel structure.
+func deleteVarFromAssignStmt(tokFile *token.File, info *types.Info, curIdent inspector.Cursor) []analysis.TextEdit {
+	var (
+		id      = curIdent.Node().(*ast.Ident)
+		curStmt = curIdent.Parent()
+		assign  = curStmt.Node().(*ast.AssignStmt)
+	)
+
+	declaresOtherNames := slices.ContainsFunc(assign.Lhs, func(lhs ast.Expr) bool {
+		lhsId, ok := lhs.(*ast.Ident)
+		return ok && lhsId != id && lhsId.Name != "_"
+	})
+	noRHSEffects := !slices.ContainsFunc(assign.Rhs, func(rhs ast.Expr) bool {
+		return !typesinternal.NoEffects(info, rhs)
+	})
+	if !declaresOtherNames && noRHSEffects {
+		// The assignment is no longer needed, either to
+		// declare other variables, or for its side effects.
+		if edits := DeleteStmt(tokFile, curStmt); edits != nil {
+			return edits
+		}
+		// Statement could not not be deleted in this context.
+		// Fall back to conservative deletion.
+	}
+
+	// The assign is still needed, either for
+	// at least one LHS, or for effects on RHS,
+	// or because it cannot deleted because of its context.
+	// Blank out or delete just one LHS.
+
+	// If the assignment is 1:1 and the RHS has no effects,
+	// we can delete the LHS and its corresponding RHS.
+	_, index := curIdent.ParentEdge()
+	if len(assign.Lhs) > 1 &&
+		len(assign.Lhs) == len(assign.Rhs) &&
+		typesinternal.NoEffects(info, assign.Rhs[index]) {
+
+		if index == len(assign.Lhs)-1 {
+			// Delete final items.
+			//
+			// _, lhs1 := rhs0, rhs1
+			//  ------        ------
+			return []analysis.TextEdit{
+				{
+					Pos: assign.Lhs[index-1].End(),
+					End: assign.Lhs[index].End(),
+				},
+				{
+					Pos: assign.Rhs[index-1].End(),
+					End: assign.Rhs[index].End(),
+				},
+			}
+		} else {
+			// Delete non-final items.
+			//
+			// lhs0, _ := rhs0, rhs1
+			// ------     ------
+			return []analysis.TextEdit{
+				{
+					Pos: assign.Lhs[index].Pos(),
+					End: assign.Lhs[index+1].Pos(),
+				},
+				{
+					Pos: assign.Rhs[index].Pos(),
+					End: assign.Rhs[index+1].Pos(),
+				},
+			}
+		}
+	}
+
+	// We cannot delete the RHS.
+	// Blank out the LHS.
+	edits := []analysis.TextEdit{{
+		Pos:     id.Pos(),
+		End:     id.End(),
+		NewText: []byte("_"),
+	}}
+
+	// If this eliminates the final variable declared by
+	// an := statement, we need to turn it into an =
+	// assignment to avoid a "no new variables on left
+	// side of :=" error.
+	if !declaresOtherNames {
+		edits = append(edits, analysis.TextEdit{
+			Pos:     assign.TokPos,
+			End:     assign.TokPos + token.Pos(len(":=")),
+			NewText: []byte("="),
+		})
+	}
+
+	return edits
+}
+
+// DeleteSpec returns edits to delete the {Type,Value}Spec identified by curSpec.
+//
+// TODO(adonovan): add test suite. Test for consts as well.
+func DeleteSpec(tokFile *token.File, curSpec inspector.Cursor) []analysis.TextEdit {
+	var (
+		spec    = curSpec.Node().(ast.Spec)
+		curDecl = curSpec.Parent()
+		decl    = curDecl.Node().(*ast.GenDecl)
+	)
+
+	// If it is the sole spec in the decl,
+	// delete the entire decl.
+	if len(decl.Specs) == 1 {
+		return DeleteDecl(tokFile, curDecl)
+	}
+
+	// Delete the spec and its comments.
+	_, index := curSpec.ParentEdge() // index of ValueSpec within GenDecl.Specs
+	pos, end := spec.Pos(), spec.End()
+	if doc := astutil.DocComment(spec); doc != nil {
+		pos = doc.Pos() // leading comment
+	}
+	if index == len(decl.Specs)-1 {
+		// Delete final spec.
+		if c := eolComment(spec); c != nil {
+			//  var (v int // comment \n)
+			end = c.End()
+		}
+	} else {
+		// Delete non-final spec.
+		//   var ( a T; b T )
+		//         -----
+		end = decl.Specs[index+1].Pos()
+	}
+	return []analysis.TextEdit{{
+		Pos: pos,
+		End: end,
+	}}
+}
+
+// DeleteDecl returns edits to delete the ast.Decl identified by curDecl.
+//
+// TODO(adonovan): add test suite.
+func DeleteDecl(tokFile *token.File, curDecl inspector.Cursor) []analysis.TextEdit {
+	decl := curDecl.Node().(ast.Decl)
+
+	ek, _ := curDecl.ParentEdge()
+	switch ek {
+	case edge.DeclStmt_Decl:
+		return DeleteStmt(tokFile, curDecl.Parent())
+
+	case edge.File_Decls:
+		pos, end := decl.Pos(), decl.End()
+		if doc := astutil.DocComment(decl); doc != nil {
+			pos = doc.Pos()
+		}
+
+		// Delete free-floating comments on same line as rparen.
+		//    var (...) // comment
+		var (
+			file        = curDecl.Parent().Node().(*ast.File)
+			lineOf      = tokFile.Line
+			declEndLine = lineOf(decl.End())
+		)
+		for _, cg := range file.Comments {
+			for _, c := range cg.List {
+				if c.Pos() < end {
+					continue // too early
+				}
+				commentEndLine := lineOf(c.End())
+				if commentEndLine > declEndLine {
+					break // too late
+				} else if lineOf(c.Pos()) == declEndLine && commentEndLine == declEndLine {
+					end = c.End()
+				}
+			}
+		}
+
+		return []analysis.TextEdit{{
+			Pos: pos,
+			End: end,
+		}}
+
+	default:
+		panic(fmt.Sprintf("Decl parent is %v, want DeclStmt or File", ek))
+	}
+}
+
+// DeleteStmt returns the edits to remove the [ast.Stmt] identified by
+// curStmt, if it is contained within a BlockStmt, CaseClause,
+// CommClause, or is the STMT in switch STMT; ... {...}. It returns nil otherwise.
+func DeleteStmt(tokFile *token.File, curStmt inspector.Cursor) []analysis.TextEdit {
+	stmt := curStmt.Node().(ast.Stmt)
+	// if the stmt is on a line by itself delete the whole line
+	// otherwise just delete the statement.
+
+	// this logic would be a lot simpler with the file contents, and somewhat simpler
+	// if the cursors included the comments.
+
+	lineOf := tokFile.Line
+	stmtStartLine, stmtEndLine := lineOf(stmt.Pos()), lineOf(stmt.End())
+
+	var from, to token.Pos
+	// bounds of adjacent syntax/comments on same line, if any
+	limits := func(left, right token.Pos) {
+		if lineOf(left) == stmtStartLine {
+			from = left
+		}
+		if lineOf(right) == stmtEndLine {
+			to = right
+		}
+	}
+	// TODO(pjw): there are other places a statement might be removed:
+	// IfStmt = "if" [ SimpleStmt ";" ] Expression Block [ "else" ( IfStmt | Block ) ] .
+	// (removing the blocks requires more rewriting than this routine would do)
+	// CommCase   = "case" ( SendStmt | RecvStmt ) | "default" .
+	// (removing the stmt requires more rewriting, and it's unclear what the user means)
+	switch parent := curStmt.Parent().Node().(type) {
+	case *ast.SwitchStmt:
+		limits(parent.Switch, parent.Body.Lbrace)
+	case *ast.TypeSwitchStmt:
+		limits(parent.Switch, parent.Body.Lbrace)
+		if parent.Assign == stmt {
+			return nil // don't let the user break the type switch
+		}
+	case *ast.BlockStmt:
+		limits(parent.Lbrace, parent.Rbrace)
+	case *ast.CommClause:
+		limits(parent.Colon, curStmt.Parent().Parent().Node().(*ast.BlockStmt).Rbrace)
+		if parent.Comm == stmt {
+			return nil // maybe the user meant to remove the entire CommClause?
+		}
+	case *ast.CaseClause:
+		limits(parent.Colon, curStmt.Parent().Parent().Node().(*ast.BlockStmt).Rbrace)
+	case *ast.ForStmt:
+		limits(parent.For, parent.Body.Lbrace)
+
+	default:
+		return nil // not one of ours
+	}
+
+	if prev, found := curStmt.PrevSibling(); found && lineOf(prev.Node().End()) == stmtStartLine {
+		from = prev.Node().End() // preceding statement ends on same line
+	}
+	if next, found := curStmt.NextSibling(); found && lineOf(next.Node().Pos()) == stmtEndLine {
+		to = next.Node().Pos() // following statement begins on same line
+	}
+	// and now for the comments
+Outer:
+	for _, cg := range astutil.EnclosingFile(curStmt).Comments {
+		for _, co := range cg.List {
+			if lineOf(co.End()) < stmtStartLine {
+				continue
+			} else if lineOf(co.Pos()) > stmtEndLine {
+				break Outer // no more are possible
+			}
+			if lineOf(co.End()) == stmtStartLine && co.End() < stmt.Pos() {
+				if !from.IsValid() || co.End() > from {
+					from = co.End()
+					continue // maybe there are more
+				}
+			}
+			if lineOf(co.Pos()) == stmtEndLine && co.Pos() > stmt.End() {
+				if !to.IsValid() || co.Pos() < to {
+					to = co.Pos()
+					continue // maybe there are more
+				}
+			}
+		}
+	}
+	// if either from or to is valid, just remove the statement
+	// otherwise remove the line
+	edit := analysis.TextEdit{Pos: stmt.Pos(), End: stmt.End()}
+	if from.IsValid() || to.IsValid() {
+		// remove just the statement.
+		// we can't tell if there is a ; or whitespace right after the statement
+		// ideally we'd like to remove the former and leave the latter
+		// (if gofmt has run, there likely won't be a ;)
+		// In type switches we know there's a semicolon somewhere after the statement,
+		// but the extra work for this special case is not worth it, as gofmt will fix it.
+		return []analysis.TextEdit{edit}
+	}
+	// remove the whole line
+	for lineOf(edit.Pos) == stmtStartLine {
+		edit.Pos--
+	}
+	edit.Pos++ // get back tostmtStartLine
+	for lineOf(edit.End) == stmtEndLine {
+		edit.End++
+	}
+	return []analysis.TextEdit{edit}
+}
+
+// DeleteUnusedVars computes the edits required to delete the
+// declarations of any local variables whose last uses are in the
+// curDelend subtree, which is about to be deleted.
+func DeleteUnusedVars(index *typeindex.Index, info *types.Info, tokFile *token.File, curDelend inspector.Cursor) []analysis.TextEdit {
+	// TODO(adonovan): we might want to generalize this by
+	// splitting the two phases below, so that we can gather
+	// across a whole sequence of deletions then finally compute the
+	// set of variables that are no longer wanted.
+
+	// Count number of deletions of each var.
+	delcount := make(map[*types.Var]int)
+	for curId := range curDelend.Preorder((*ast.Ident)(nil)) {
+		id := curId.Node().(*ast.Ident)
+		if v, ok := info.Uses[id].(*types.Var); ok &&
+			typesinternal.GetVarKind(v) == typesinternal.LocalVar { // always false before go1.25
+			delcount[v]++
+		}
+	}
+
+	// Delete declaration of each var that became unused.
+	var edits []analysis.TextEdit
+	for v, count := range delcount {
+		if len(slices.Collect(index.Uses(v))) == count {
+			if curDefId, ok := index.Def(v); ok {
+				edits = append(edits, DeleteVar(tokFile, info, curDefId)...)
+			}
+		}
+	}
+	return edits
+}
+
+func eolComment(n ast.Node) *ast.CommentGroup {
+	// TODO(adonovan): support:
+	//    func f() {...} // comment
+	switch n := n.(type) {
+	case *ast.GenDecl:
+		if !n.TokPos.IsValid() && len(n.Specs) == 1 {
+			return eolComment(n.Specs[0])
+		}
+	case *ast.ValueSpec:
+		return n.Comment
+	case *ast.TypeSpec:
+		return n.Comment
+	}
+	return nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/imports.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/imports.go
new file mode 100644
index 00000000000000..b5440d896b9bfc
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/imports.go
@@ -0,0 +1,127 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package refactor
+
+// This file defines operations for computing edits to imports.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	pathpkg "path"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/internal/packagepath"
+)
+
+// AddImport returns the prefix (either "pkg." or "") that should be
+// used to qualify references to the desired symbol (member) imported
+// from the specified package, plus any necessary edits to the file's
+// import declaration to add a new import.
+//
+// If the import already exists, and is accessible at pos, AddImport
+// returns the existing name and no edits. (If the existing import is
+// a dot import, the prefix is "".)
+//
+// Otherwise, it adds a new import, using a local name derived from
+// the preferred name. To request a blank import, use a preferredName
+// of "_", and discard the prefix result; member is ignored in this
+// case.
+//
+// AddImport accepts the caller's implicit claim that the imported
+// package declares member.
+//
+// AddImport does not mutate its arguments.
+func AddImport(info *types.Info, file *ast.File, preferredName, pkgpath, member string, pos token.Pos) (prefix string, edits []analysis.TextEdit) {
+	// Find innermost enclosing lexical block.
+	scope := info.Scopes[file].Innermost(pos)
+	if scope == nil {
+		panic("no enclosing lexical block")
+	}
+
+	// Is there an existing import of this package?
+	// If so, are we in its scope? (not shadowed)
+	for _, spec := range file.Imports {
+		pkgname := info.PkgNameOf(spec)
+		if pkgname != nil && pkgname.Imported().Path() == pkgpath {
+			name := pkgname.Name()
+			if preferredName == "_" {
+				// Request for blank import; any existing import will do.
+				return "", nil
+			}
+			if name == "." {
+				// The scope of ident must be the file scope.
+				if s, _ := scope.LookupParent(member, pos); s == info.Scopes[file] {
+					return "", nil
+				}
+			} else if _, obj := scope.LookupParent(name, pos); obj == pkgname {
+				return name + ".", nil
+			}
+		}
+	}
+
+	// We must add a new import.
+
+	// Ensure we have a fresh name.
+	newName := preferredName
+	if preferredName != "_" {
+		newName = FreshName(scope, pos, preferredName)
+	}
+
+	// Create a new import declaration either before the first existing
+	// declaration (which must exist), including its comments; or
+	// inside the declaration, if it is an import group.
+	//
+	// Use a renaming import whenever the preferred name is not
+	// available, or the chosen name does not match the last
+	// segment of its path.
+	newText := fmt.Sprintf("%q", pkgpath)
+	if newName != preferredName || newName != pathpkg.Base(pkgpath) {
+		newText = fmt.Sprintf("%s %q", newName, pkgpath)
+	}
+
+	decl0 := file.Decls[0]
+	var before ast.Node = decl0
+	switch decl0 := decl0.(type) {
+	case *ast.GenDecl:
+		if decl0.Doc != nil {
+			before = decl0.Doc
+		}
+	case *ast.FuncDecl:
+		if decl0.Doc != nil {
+			before = decl0.Doc
+		}
+	}
+	if gd, ok := before.(*ast.GenDecl); ok && gd.Tok == token.IMPORT && gd.Rparen.IsValid() {
+		// Have existing grouped import ( ... ) decl.
+		if packagepath.IsStdPackage(pkgpath) && len(gd.Specs) > 0 {
+			// Add spec for a std package before
+			// first existing spec, followed by
+			// a blank line if the next one is non-std.
+			first := gd.Specs[0].(*ast.ImportSpec)
+			pos = first.Pos()
+			if !packagepath.IsStdPackage(first.Path.Value) {
+				newText += "\n"
+			}
+			newText += "\n\t"
+		} else {
+			// Add spec at end of group.
+			pos = gd.Rparen
+			newText = "\t" + newText + "\n"
+		}
+	} else {
+		// No import decl, or non-grouped import.
+		// Add a new import decl before first decl.
+		// (gofmt will merge multiple import decls.)
+		pos = before.Pos()
+		newText = "import " + newText + "\n\n"
+	}
+	return newName + ".", []analysis.TextEdit{{
+		Pos:     pos,
+		End:     pos,
+		NewText: []byte(newText),
+	}}
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/refactor.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/refactor.go
new file mode 100644
index 00000000000000..27b975089618b5
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/refactor.go
@@ -0,0 +1,29 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package refactor provides operators to compute common textual edits
+// for refactoring tools.
+//
+// This package should not use features of the analysis API
+// other than [analysis.TextEdit].
+package refactor
+
+import (
+	"fmt"
+	"go/token"
+	"go/types"
+)
+
+// FreshName returns the name of an identifier that is undefined
+// at the specified position, based on the preferred name.
+func FreshName(scope *types.Scope, pos token.Pos, preferred string) string {
+	newName := preferred
+	for i := 0; ; i++ {
+		if _, obj := scope.LookupParent(newName, pos); obj == nil {
+			break // fresh
+		}
+		newName = fmt.Sprintf("%s%d", preferred, i)
+	}
+	return newName
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/fx.go b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/fx.go
new file mode 100644
index 00000000000000..c846a53d5fe7f5
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/fx.go
@@ -0,0 +1,88 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typesinternal
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+// NoEffects reports whether the expression has no side effects, i.e., it
+// does not modify the memory state. This function is conservative: it may
+// return false even when the expression has no effect.
+func NoEffects(info *types.Info, expr ast.Expr) bool {
+	noEffects := true
+	ast.Inspect(expr, func(n ast.Node) bool {
+		switch v := n.(type) {
+		case nil, *ast.Ident, *ast.BasicLit, *ast.BinaryExpr, *ast.ParenExpr,
+			*ast.SelectorExpr, *ast.IndexExpr, *ast.SliceExpr, *ast.TypeAssertExpr,
+			*ast.StarExpr, *ast.CompositeLit,
+			// non-expressions that may appear within expressions
+			*ast.KeyValueExpr,
+			*ast.FieldList,
+			*ast.Field,
+			*ast.Ellipsis,
+			*ast.IndexListExpr:
+			// No effect.
+
+		case *ast.ArrayType,
+			*ast.StructType,
+			*ast.ChanType,
+			*ast.FuncType,
+			*ast.MapType,
+			*ast.InterfaceType:
+			// Type syntax: no effects, recursively.
+			// Prune descent.
+			return false
+
+		case *ast.UnaryExpr:
+			// Channel send <-ch has effects.
+			if v.Op == token.ARROW {
+				noEffects = false
+			}
+
+		case *ast.CallExpr:
+			// Type conversion has no effects.
+			if !info.Types[v.Fun].IsType() {
+				if CallsPureBuiltin(info, v) {
+					// A call such as len(e) has no effects of its
+					// own, though the subexpression e might.
+				} else {
+					noEffects = false
+				}
+			}
+
+		case *ast.FuncLit:
+			// A FuncLit has no effects, but do not descend into it.
+			return false
+
+		default:
+			// All other expressions have effects
+			noEffects = false
+		}
+
+		return noEffects
+	})
+	return noEffects
+}
+
+// CallsPureBuiltin reports whether call is a call of a built-in
+// function that is a pure computation over its operands (analogous to
+// a + operator). Because it does not depend on program state, it may
+// be evaluated at any point--though not necessarily at multiple
+// points (consider new, make).
+func CallsPureBuiltin(info *types.Info, call *ast.CallExpr) bool {
+	if id, ok := ast.Unparen(call.Fun).(*ast.Ident); ok {
+		if b, ok := info.ObjectOf(id).(*types.Builtin); ok {
+			switch b.Name() {
+			case "len", "cap", "complex", "imag", "real", "make", "new", "max", "min":
+				return true
+			}
+			// Not: append clear close copy delete panic print println recover
+		}
+	}
+	return false
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/isnamed.go b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/isnamed.go
new file mode 100644
index 00000000000000..f2affec4fba929
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/isnamed.go
@@ -0,0 +1,71 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typesinternal
+
+import (
+	"go/types"
+	"slices"
+)
+
+// IsTypeNamed reports whether t is (or is an alias for) a
+// package-level defined type with the given package path and one of
+// the given names. It returns false if t is nil.
+//
+// This function avoids allocating the concatenation of "pkg.Name",
+// which is important for the performance of syntax matching.
+func IsTypeNamed(t types.Type, pkgPath string, names ...string) bool {
+	if named, ok := types.Unalias(t).(*types.Named); ok {
+		tname := named.Obj()
+		return tname != nil &&
+			IsPackageLevel(tname) &&
+			tname.Pkg().Path() == pkgPath &&
+			slices.Contains(names, tname.Name())
+	}
+	return false
+}
+
+// IsPointerToNamed reports whether t is (or is an alias for) a pointer to a
+// package-level defined type with the given package path and one of the given
+// names. It returns false if t is not a pointer type.
+func IsPointerToNamed(t types.Type, pkgPath string, names ...string) bool {
+	r := Unpointer(t)
+	if r == t {
+		return false
+	}
+	return IsTypeNamed(r, pkgPath, names...)
+}
+
+// IsFunctionNamed reports whether obj is a package-level function
+// defined in the given package and has one of the given names.
+// It returns false if obj is nil.
+//
+// This function avoids allocating the concatenation of "pkg.Name",
+// which is important for the performance of syntax matching.
+func IsFunctionNamed(obj types.Object, pkgPath string, names ...string) bool {
+	f, ok := obj.(*types.Func)
+	return ok &&
+		IsPackageLevel(obj) &&
+		f.Pkg().Path() == pkgPath &&
+		f.Type().(*types.Signature).Recv() == nil &&
+		slices.Contains(names, f.Name())
+}
+
+// IsMethodNamed reports whether obj is a method defined on a
+// package-level type with the given package and type name, and has
+// one of the given names. It returns false if obj is nil.
+//
+// This function avoids allocating the concatenation of "pkg.TypeName.Name",
+// which is important for the performance of syntax matching.
+func IsMethodNamed(obj types.Object, pkgPath string, typeName string, names ...string) bool {
+	if fn, ok := obj.(*types.Func); ok {
+		if recv := fn.Type().(*types.Signature).Recv(); recv != nil {
+			_, T := ReceiverNamed(recv)
+			return T != nil &&
+				IsTypeNamed(T, pkgPath, typeName) &&
+				slices.Contains(names, fn.Name())
+		}
+	}
+	return false
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/types.go b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/types.go
index a5cd7e8dbfcb9d..fef74a78560480 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/types.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/types.go
@@ -2,8 +2,20 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package typesinternal provides access to internal go/types APIs that are not
-// yet exported.
+// Package typesinternal provides helpful operators for dealing with
+// go/types:
+//
+//   - operators for querying typed syntax trees (e.g. [Imports], [IsFunctionNamed]);
+//   - functions for converting types to strings or syntax (e.g. [TypeExpr], FileQualifier]);
+//   - helpers for working with the [go/types] API (e.g. [NewTypesInfo]);
+//   - access to internal go/types APIs that are not yet
+//     exported (e.g. [SetUsesCgo], [ErrorCodeStartEnd], [VarKind]); and
+//   - common algorithms related to types (e.g. [TooNewStdSymbols]).
+//
+// See also:
+//   - [golang.org/x/tools/internal/astutil], for operations on untyped syntax;
+//   - [golang.org/x/tools/internal/analysisinernal], for helpers for analyzers;
+//   - [golang.org/x/tools/internal/refactor], for operators to compute text edits.
 package typesinternal
 
 import (
@@ -13,6 +25,7 @@ import (
 	"reflect"
 	"unsafe"
 
+	"golang.org/x/tools/go/ast/inspector"
 	"golang.org/x/tools/internal/aliases"
 )
 
@@ -60,6 +73,9 @@ func ErrorCodeStartEnd(err types.Error) (code ErrorCode, start, end token.Pos, o
 // which is often excessive.)
 //
 // If pkg is nil, it is equivalent to [*types.Package.Name].
+//
+// TODO(adonovan): all uses of this with TypeString should be
+// eliminated when https://go.dev/issues/75604 is resolved.
 func NameRelativeTo(pkg *types.Package) types.Qualifier {
 	return func(other *types.Package) string {
 		if pkg != nil && pkg == other {
@@ -153,3 +169,31 @@ func NewTypesInfo() *types.Info {
 		FileVersions: map[*ast.File]string{},
 	}
 }
+
+// EnclosingScope returns the innermost block logically enclosing the cursor.
+func EnclosingScope(info *types.Info, cur inspector.Cursor) *types.Scope {
+	for cur := range cur.Enclosing() {
+		n := cur.Node()
+		// A function's Scope is associated with its FuncType.
+		switch f := n.(type) {
+		case *ast.FuncDecl:
+			n = f.Type
+		case *ast.FuncLit:
+			n = f.Type
+		}
+		if b := info.Scopes[n]; b != nil {
+			return b
+		}
+	}
+	panic("no Scope for *ast.File")
+}
+
+// Imports reports whether path is imported by pkg.
+func Imports(pkg *types.Package, path string) bool {
+	for _, imp := range pkg.Imports() {
+		if imp.Path() == path {
+			return true
+		}
+	}
+	return false
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/varkind.go b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/varkind.go
index e5da0495111ba1..26499cdd2e70fb 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/varkind.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/varkind.go
@@ -2,39 +2,22 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package typesinternal
+//go:build go1.25
 
-// TODO(adonovan): when CL 645115 lands, define the go1.25 version of
-// this API that actually does something.
+package typesinternal
 
 import "go/types"
 
-type VarKind uint8
+type VarKind = types.VarKind
 
 const (
-	_          VarKind = iota // (not meaningful)
-	PackageVar                // a package-level variable
-	LocalVar                  // a local variable
-	RecvVar                   // a method receiver variable
-	ParamVar                  // a function parameter variable
-	ResultVar                 // a function result variable
-	FieldVar                  // a struct field
+	PackageVar = types.PackageVar
+	LocalVar   = types.LocalVar
+	RecvVar    = types.RecvVar
+	ParamVar   = types.ParamVar
+	ResultVar  = types.ResultVar
+	FieldVar   = types.FieldVar
 )
 
-func (kind VarKind) String() string {
-	return [...]string{
-		0:          "VarKind(0)",
-		PackageVar: "PackageVar",
-		LocalVar:   "LocalVar",
-		RecvVar:    "RecvVar",
-		ParamVar:   "ParamVar",
-		ResultVar:  "ResultVar",
-		FieldVar:   "FieldVar",
-	}[kind]
-}
-
-// GetVarKind returns an invalid VarKind.
-func GetVarKind(v *types.Var) VarKind { return 0 }
-
-// SetVarKind has no effect.
-func SetVarKind(v *types.Var, kind VarKind) {}
+func GetVarKind(v *types.Var) VarKind       { return v.Kind() }
+func SetVarKind(v *types.Var, kind VarKind) { v.SetKind(kind) }
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/varkind_go124.go b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/varkind_go124.go
new file mode 100644
index 00000000000000..17b1804b4e85e1
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/varkind_go124.go
@@ -0,0 +1,39 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.25
+
+package typesinternal
+
+import "go/types"
+
+type VarKind uint8
+
+const (
+	_          VarKind = iota // (not meaningful)
+	PackageVar                // a package-level variable
+	LocalVar                  // a local variable
+	RecvVar                   // a method receiver variable
+	ParamVar                  // a function parameter variable
+	ResultVar                 // a function result variable
+	FieldVar                  // a struct field
+)
+
+func (kind VarKind) String() string {
+	return [...]string{
+		0:          "VarKind(0)",
+		PackageVar: "PackageVar",
+		LocalVar:   "LocalVar",
+		RecvVar:    "RecvVar",
+		ParamVar:   "ParamVar",
+		ResultVar:  "ResultVar",
+		FieldVar:   "FieldVar",
+	}[kind]
+}
+
+// GetVarKind returns an invalid VarKind.
+func GetVarKind(v *types.Var) VarKind { return 0 }
+
+// SetVarKind has no effect.
+func SetVarKind(v *types.Var, kind VarKind) {}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/zerovalue.go b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/zerovalue.go
index d272949c177189..453bba2ad5e840 100644
--- a/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/zerovalue.go
+++ b/src/cmd/vendor/golang.org/x/tools/internal/typesinternal/zerovalue.go
@@ -204,23 +204,12 @@ func ZeroExpr(t types.Type, qual types.Qualifier) (_ ast.Expr, isValid bool) {
 	}
 }
 
-// IsZeroExpr uses simple syntactic heuristics to report whether expr
-// is a obvious zero value, such as 0, "", nil, or false.
-// It cannot do better without type information.
-func IsZeroExpr(expr ast.Expr) bool {
-	switch e := expr.(type) {
-	case *ast.BasicLit:
-		return e.Value == "0" || e.Value == `""`
-	case *ast.Ident:
-		return e.Name == "nil" || e.Name == "false"
-	default:
-		return false
-	}
-}
-
 // TypeExpr returns syntax for the specified type. References to named types
 // are qualified by an appropriate (optional) qualifier function.
 // It may panic for types such as Tuple or Union.
+//
+// See also https://go.dev/issues/75604, which will provide a robust
+// Type-to-valid-Go-syntax formatter.
 func TypeExpr(t types.Type, qual types.Qualifier) ast.Expr {
 	switch t := t.(type) {
 	case *types.Basic:
diff --git a/src/cmd/vendor/modules.txt b/src/cmd/vendor/modules.txt
index 133271355f2caf..f4c60cc3281b78 100644
--- a/src/cmd/vendor/modules.txt
+++ b/src/cmd/vendor/modules.txt
@@ -28,7 +28,7 @@ golang.org/x/arch/x86/x86asm
 # golang.org/x/build v0.0.0-20250806225920-b7c66c047964
 ## explicit; go 1.23.0
 golang.org/x/build/relnote
-# golang.org/x/mod v0.28.0
+# golang.org/x/mod v0.29.0
 ## explicit; go 1.24.0
 golang.org/x/mod/internal/lazyregexp
 golang.org/x/mod/modfile
@@ -43,12 +43,12 @@ golang.org/x/mod/zip
 ## explicit; go 1.24.0
 golang.org/x/sync/errgroup
 golang.org/x/sync/semaphore
-# golang.org/x/sys v0.36.0
+# golang.org/x/sys v0.37.0
 ## explicit; go 1.24.0
 golang.org/x/sys/plan9
 golang.org/x/sys/unix
 golang.org/x/sys/windows
-# golang.org/x/telemetry v0.0.0-20250908211612-aef8a434d053
+# golang.org/x/telemetry v0.0.0-20251008203120-078029d740a8
 ## explicit; go 1.24.0
 golang.org/x/telemetry
 golang.org/x/telemetry/counter
@@ -63,7 +63,7 @@ golang.org/x/telemetry/internal/upload
 # golang.org/x/term v0.34.0
 ## explicit; go 1.23.0
 golang.org/x/term
-# golang.org/x/text v0.29.0
+# golang.org/x/text v0.30.0
 ## explicit; go 1.24.0
 golang.org/x/text/cases
 golang.org/x/text/internal
@@ -73,7 +73,7 @@ golang.org/x/text/internal/tag
 golang.org/x/text/language
 golang.org/x/text/transform
 golang.org/x/text/unicode/norm
-# golang.org/x/tools v0.37.1-0.20250924232827-4df13e317ce4
+# golang.org/x/tools v0.38.1-0.20251015192825-7d9453ccc0f5
 ## explicit; go 1.24.0
 golang.org/x/tools/cmd/bisect
 golang.org/x/tools/cover
@@ -97,7 +97,6 @@ golang.org/x/tools/go/analysis/passes/hostport
 golang.org/x/tools/go/analysis/passes/httpresponse
 golang.org/x/tools/go/analysis/passes/ifaceassert
 golang.org/x/tools/go/analysis/passes/inspect
-golang.org/x/tools/go/analysis/passes/internal/analysisutil
 golang.org/x/tools/go/analysis/passes/loopclosure
 golang.org/x/tools/go/analysis/passes/lostcancel
 golang.org/x/tools/go/analysis/passes/nilfunc
@@ -133,6 +132,8 @@ golang.org/x/tools/internal/diff/lcs
 golang.org/x/tools/internal/facts
 golang.org/x/tools/internal/fmtstr
 golang.org/x/tools/internal/moreiters
+golang.org/x/tools/internal/packagepath
+golang.org/x/tools/internal/refactor
 golang.org/x/tools/internal/stdlib
 golang.org/x/tools/internal/typeparams
 golang.org/x/tools/internal/typesinternal
diff --git a/src/go.mod b/src/go.mod
index f134f0c7b571da..c5e901b9ef22e8 100644
--- a/src/go.mod
+++ b/src/go.mod
@@ -3,11 +3,11 @@ module std
 go 1.26
 
 require (
-	golang.org/x/crypto v0.42.0
-	golang.org/x/net v0.44.1-0.20251002015445-edb764c2296f
+	golang.org/x/crypto v0.43.0
+	golang.org/x/net v0.46.0
 )
 
 require (
-	golang.org/x/sys v0.36.0 // indirect
-	golang.org/x/text v0.29.0 // indirect
+	golang.org/x/sys v0.37.0 // indirect
+	golang.org/x/text v0.30.0 // indirect
 )
diff --git a/src/go.sum b/src/go.sum
index f24bea029a2239..4a52682161fc23 100644
--- a/src/go.sum
+++ b/src/go.sum
@@ -1,8 +1,8 @@
-golang.org/x/crypto v0.42.0 h1:chiH31gIWm57EkTXpwnqf8qeuMUi0yekh6mT2AvFlqI=
-golang.org/x/crypto v0.42.0/go.mod h1:4+rDnOTJhQCx2q7/j6rAN5XDw8kPjeaXEUR2eL94ix8=
-golang.org/x/net v0.44.1-0.20251002015445-edb764c2296f h1:vNklv+oJQSYNGsWXHoCPi2MHMcpj9/Q7aBhvvfnJvGg=
-golang.org/x/net v0.44.1-0.20251002015445-edb764c2296f/go.mod h1:ECOoLqd5U3Lhyeyo/QDCEVQ4sNgYsqvCZ722XogGieY=
-golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
-golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
-golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
-golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=
+golang.org/x/crypto v0.43.0 h1:dduJYIi3A3KOfdGOHX8AVZ/jGiyPa3IbBozJ5kNuE04=
+golang.org/x/crypto v0.43.0/go.mod h1:BFbav4mRNlXJL4wNeejLpWxB7wMbc79PdRGhWKncxR0=
+golang.org/x/net v0.46.0 h1:giFlY12I07fugqwPuWJi68oOnpfqFnJIJzaIIm2JVV4=
+golang.org/x/net v0.46.0/go.mod h1:Q9BGdFy1y4nkUwiLvT5qtyhAnEHgnQ/zd8PfU6nc210=
+golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
+golang.org/x/sys v0.37.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/text v0.30.0 h1:yznKA/E9zq54KzlzBEAWn1NXSQ8DIp/NYMy88xJjl4k=
+golang.org/x/text v0.30.0/go.mod h1:yDdHFIX9t+tORqspjENWgzaCVXgk0yYnYuSZ8UzzBVM=
diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go
index f09e102efb7b1c..0df276321cf09e 100644
--- a/src/net/http/h2_bundle.go
+++ b/src/net/http/h2_bundle.go
@@ -11695,6 +11695,12 @@ func (ws *http2priorityWriteSchedulerRFC9218) AdjustStream(streamID uint32, prio
 		q.prev.next = q
 		q.next.prev = q
 	}
+
+	// Update the metadata.
+	ws.streams[streamID] = http2streamMetadata{
+		location: q,
+		priority: priority,
+	}
 }
 
 func (ws *http2priorityWriteSchedulerRFC9218) Push(wr http2FrameWriteRequest) {
diff --git a/src/vendor/golang.org/x/text/unicode/bidi/core.go b/src/vendor/golang.org/x/text/unicode/bidi/core.go
index 9d2ae547b5ed4d..fb8273236dde6e 100644
--- a/src/vendor/golang.org/x/text/unicode/bidi/core.go
+++ b/src/vendor/golang.org/x/text/unicode/bidi/core.go
@@ -427,13 +427,6 @@ type isolatingRunSequence struct {
 
 func (i *isolatingRunSequence) Len() int { return len(i.indexes) }
 
-func maxLevel(a, b level) level {
-	if a > b {
-		return a
-	}
-	return b
-}
-
 // Rule X10, second bullet: Determine the start-of-sequence (sos) and end-of-sequence (eos) types,
 // either L or R, for each isolating run sequence.
 func (p *paragraph) isolatingRunSequence(indexes []int) *isolatingRunSequence {
@@ -474,8 +467,8 @@ func (p *paragraph) isolatingRunSequence(indexes []int) *isolatingRunSequence {
 		indexes: indexes,
 		types:   types,
 		level:   level,
-		sos:     typeForLevel(maxLevel(prevLevel, level)),
-		eos:     typeForLevel(maxLevel(succLevel, level)),
+		sos:     typeForLevel(max(prevLevel, level)),
+		eos:     typeForLevel(max(succLevel, level)),
 	}
 }
 
diff --git a/src/vendor/modules.txt b/src/vendor/modules.txt
index a2a0c0b3e85f23..f1e33686ed0626 100644
--- a/src/vendor/modules.txt
+++ b/src/vendor/modules.txt
@@ -1,4 +1,4 @@
-# golang.org/x/crypto v0.42.0
+# golang.org/x/crypto v0.43.0
 ## explicit; go 1.24.0
 golang.org/x/crypto/chacha20
 golang.org/x/crypto/chacha20poly1305
@@ -6,7 +6,7 @@ golang.org/x/crypto/cryptobyte
 golang.org/x/crypto/cryptobyte/asn1
 golang.org/x/crypto/internal/alias
 golang.org/x/crypto/internal/poly1305
-# golang.org/x/net v0.44.1-0.20251002015445-edb764c2296f
+# golang.org/x/net v0.46.0
 ## explicit; go 1.24.0
 golang.org/x/net/dns/dnsmessage
 golang.org/x/net/http/httpguts
@@ -15,10 +15,10 @@ golang.org/x/net/http2/hpack
 golang.org/x/net/idna
 golang.org/x/net/lif
 golang.org/x/net/nettest
-# golang.org/x/sys v0.36.0
+# golang.org/x/sys v0.37.0
 ## explicit; go 1.24.0
 golang.org/x/sys/cpu
-# golang.org/x/text v0.29.0
+# golang.org/x/text v0.30.0
 ## explicit; go 1.24.0
 golang.org/x/text/secure/bidirule
 golang.org/x/text/transform

From e7351c03c8b36e0639a3a581131217f52e99b1ac Mon Sep 17 00:00:00 2001
From: Vasily Leonenko 
Date: Sat, 23 Aug 2025 12:27:22 +0300
Subject: [PATCH 163/229] runtime: use DC ZVA instead of its encoding in WORD
 in arm64 memclr

Change-Id: I900a96b985f4d9378d25b9256c4274610fc2f70e
Reviewed-on: https://go-review.googlesource.com/c/go/+/698417
Reviewed-by: Cherry Mui 
Reviewed-by: Carlos Amedee 
LUCI-TryBot-Result: Go LUCI 
---
 src/runtime/memclr_arm64.s | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/runtime/memclr_arm64.s b/src/runtime/memclr_arm64.s
index 3e49f7fcf6a26f..3f8acdaeff670f 100644
--- a/src/runtime/memclr_arm64.s
+++ b/src/runtime/memclr_arm64.s
@@ -176,7 +176,7 @@ aligned:
 
 	PCALIGN	$16
 loop_zva:
-	WORD	$0xd50b7420 // DC ZVA, R0
+	DC	ZVA, R0
 	ADD	R5, R0, R0
 	SUBS	R5, R1, R1
 	BHS	loop_zva

From 41f5659347f9498ce81911032bb46537d923bdd7 Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Thu, 16 Oct 2025 10:33:34 -0700
Subject: [PATCH 164/229] go/types, types2: remove superfluous unalias call
 (minor cleanup)

Change-Id: Ifc0d6e999777513498f070c5bc2fb4640d38c671
Reviewed-on: https://go-review.googlesource.com/c/go/+/712460
Reviewed-by: Robert Griesemer 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Robert Griesemer 
Reviewed-by: Mark Freeman 
---
 src/cmd/compile/internal/types2/alias.go     | 1 -
 src/cmd/compile/internal/types2/signature.go | 2 +-
 src/go/types/alias.go                        | 1 -
 src/go/types/signature.go                    | 2 +-
 4 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/cmd/compile/internal/types2/alias.go b/src/cmd/compile/internal/types2/alias.go
index 90dda18cc88426..d306600ebd2710 100644
--- a/src/cmd/compile/internal/types2/alias.go
+++ b/src/cmd/compile/internal/types2/alias.go
@@ -113,7 +113,6 @@ func unalias(a0 *Alias) Type {
 	for a := a0; a != nil; a, _ = t.(*Alias) {
 		t = a.fromRHS
 	}
-
 	// It's fine to memoize nil types since it's the zero value for actual.
 	// It accomplishes nothing.
 	a0.actual = t
diff --git a/src/cmd/compile/internal/types2/signature.go b/src/cmd/compile/internal/types2/signature.go
index ea1cfd88cc60b4..1e004eef4aeda6 100644
--- a/src/cmd/compile/internal/types2/signature.go
+++ b/src/cmd/compile/internal/types2/signature.go
@@ -203,7 +203,7 @@ func (check *Checker) collectRecv(rparam *syntax.Field, scopePos syntax.Pos) (*V
 			case *Alias:
 				// Methods on generic aliases are not permitted.
 				// Only report an error if the alias type is valid.
-				if isValid(unalias(t)) {
+				if isValid(t) {
 					check.errorf(rbase, InvalidRecv, "cannot define new methods on generic alias type %s", t)
 				}
 				// Ok to continue but do not set basetype in this case so that
diff --git a/src/go/types/alias.go b/src/go/types/alias.go
index f15ff570303540..a2eeb3afac8e85 100644
--- a/src/go/types/alias.go
+++ b/src/go/types/alias.go
@@ -116,7 +116,6 @@ func unalias(a0 *Alias) Type {
 	for a := a0; a != nil; a, _ = t.(*Alias) {
 		t = a.fromRHS
 	}
-
 	// It's fine to memoize nil types since it's the zero value for actual.
 	// It accomplishes nothing.
 	a0.actual = t
diff --git a/src/go/types/signature.go b/src/go/types/signature.go
index fa41c797b29403..972de97b1a1762 100644
--- a/src/go/types/signature.go
+++ b/src/go/types/signature.go
@@ -226,7 +226,7 @@ func (check *Checker) collectRecv(rparam *ast.Field, scopePos token.Pos) (*Var,
 			case *Alias:
 				// Methods on generic aliases are not permitted.
 				// Only report an error if the alias type is valid.
-				if isValid(unalias(t)) {
+				if isValid(t) {
 					check.errorf(rbase, InvalidRecv, "cannot define new methods on generic alias type %s", t)
 				}
 				// Ok to continue but do not set basetype in this case so that

From 1099436f1b63560a0587dd4c5814edd13f80e577 Mon Sep 17 00:00:00 2001
From: Mark Freeman 
Date: Wed, 20 Aug 2025 17:30:26 -0400
Subject: [PATCH 165/229] go/types, types2: change and enforce lifecycle of
 Named.fromRHS and Named.underlying fields

A type definition or alias declaration consists of a type name (LHS)
which is bound to a type expression (RHS) by the declaration.

This CL consistently uses the fromRHS fields of Named and Alias types
to represent that RHS type expression, and sets Named.underlying and
Alias.actual only once those types have been computed.

Currently, Named types use Named.underlying for some of this
functionality, which makes the code difficult to understand. Operations
which used Named.underlying now use Named.fromRHS.

For example, in:

  type A = B
  type B = int

A.fromRHS is B (Alias) and B.fromRHS is int (Basic).

Meanwhile, in:

  type A B
  type B int

A.underlying is B (Named) and B.underlying is int (Basic) initially.

Note that despite A.underlying pointing to B, B is not the underlying
type of A (it is int). At some point during type checking, A walks
through the chain A.underlying -> B.underlying -> int and sets
A.underlying to int.

While this approach works, it introduces some problems:

  1. Whether A.underlying refers to the underlying type (int) or not
     (B) depends on when the field is accessed.
  2. There is no convenient mechanism to check if the underlying type
     of B has been deduced. One can check if B.underlying is a named
     type, but since B.underlying is already B's underlying type (int),
     it's still ambiguous.

Operations derived from Named.underlying share similar problems. For
example, Named.expandUnderlying() (which substitutes type arguments)
returns an instantiated named type whose Named.underlying also may or
may not refer to its underlying type.

With this change, Named.underlying is nil as long as it is unknown, and
non-nil and not a named type once it is known. Additional assertions are
added to enforce that:

  1. Named.underlying is not set until Named has been resolved.
  2. Named is not resolved until Named.fromRHS is populated, unless it
     is given explicit permission. This permission is briefly given
     while type-checking declarations of named types to account for
     cycles of alias types represented as TypeNames. It is also given to
     named types created through NewNamed for backward compatibility.
     This permission is revoked when SetUnderlying is called.

Accessors of Named.underlying are responsible for first resolving
the named type, unless they are in a context where they know the
type to already be resolved.

This change also exposed a bug in validType wherein the underlying
type for struct types containing invalid types did not have their
underlying type set to invalid (see #75194). This bug was exploited by a
test in x/tools, which has been disabled for Go 1.26 (via CL 700395).

Other minor adjustments are made for instantiated and loaded types.
Instantiated types have no RHS as they are not declared, and loaded
types set their RHS to the underlying from export data directly.

Minor simplifications are also made throughout.

Fixes #75194

Change-Id: I72644d7329c996eb1e67514063fe51c3ae06c38d
Reviewed-on: https://go-review.googlesource.com/c/go/+/695977
Auto-Submit: Mark Freeman 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Robert Griesemer 
---
 src/cmd/compile/internal/types2/decl.go       |  25 +-
 src/cmd/compile/internal/types2/named.go      | 365 +++++++++---------
 src/cmd/compile/internal/types2/object.go     |   3 +-
 src/cmd/compile/internal/types2/signature.go  |   2 +-
 .../compile/internal/types2/sizeof_test.go    |   2 +-
 src/cmd/compile/internal/types2/typexpr.go    |   2 +-
 src/cmd/compile/internal/types2/under.go      |   4 +-
 src/cmd/compile/internal/types2/unify.go      |   2 +-
 src/cmd/compile/internal/types2/universe.go   |  10 +-
 src/cmd/compile/internal/types2/validtype.go  |  12 +-
 src/go/types/decl.go                          |  25 +-
 src/go/types/named.go                         | 365 +++++++++---------
 src/go/types/object.go                        |   3 +-
 src/go/types/signature.go                     |   2 +-
 src/go/types/sizeof_test.go                   |   2 +-
 src/go/types/typexpr.go                       |   2 +-
 src/go/types/under.go                         |   4 +-
 src/go/types/unify.go                         |   2 +-
 src/go/types/universe.go                      |  10 +-
 src/go/types/validtype.go                     |  12 +-
 .../types/testdata/fixedbugs/issue75194.go    |  14 +
 21 files changed, 442 insertions(+), 426 deletions(-)
 create mode 100644 src/internal/types/testdata/fixedbugs/issue75194.go

diff --git a/src/cmd/compile/internal/types2/decl.go b/src/cmd/compile/internal/types2/decl.go
index 22fccc15199e87..70e79129c91437 100644
--- a/src/cmd/compile/internal/types2/decl.go
+++ b/src/cmd/compile/internal/types2/decl.go
@@ -476,7 +476,7 @@ func (check *Checker) isImportedConstraint(typ Type) bool {
 	if named == nil || named.obj.pkg == check.pkg || named.obj.pkg == nil {
 		return false
 	}
-	u, _ := named.under().(*Interface)
+	u, _ := named.Underlying().(*Interface)
 	return u != nil && !u.IsMethodSet()
 }
 
@@ -558,28 +558,33 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *TypeN
 	named := check.newNamed(obj, nil, nil)
 	setDefType(def, named)
 
+	// The RHS of a named N can be nil if, for example, N is defined as a cycle of aliases with
+	// gotypesalias=0. Consider:
+	//
+	//   type D N    // N.resolve() will panic
+	//   type N A
+	//   type A = N  // N.fromRHS is not set before N.resolve(), since A does not call setDefType
+	//
+	// There is likely a better way to detect such cases, but it may not be worth the effort.
+	// Instead, we briefly permit a nil N.fromRHS while type-checking D.
+	named.allowNilRHS = true
+	defer (func() { named.allowNilRHS = false })()
+
 	if tdecl.TParamList != nil {
 		check.openScope(tdecl, "type parameters")
 		defer check.closeScope()
 		check.collectTypeParams(&named.tparams, tdecl.TParamList)
 	}
 
-	// determine underlying type of named
 	rhs = check.definedType(tdecl.Type, obj)
 	assert(rhs != nil)
 	named.fromRHS = rhs
 
-	// If the underlying type was not set while type-checking the right-hand
-	// side, it is invalid and an error should have been reported elsewhere.
-	if named.underlying == nil {
-		named.underlying = Typ[Invalid]
-	}
-
 	// spec: "In a type definition the given type cannot be a type parameter."
 	// (See also go.dev/issue/45639.)
 	if isTypeParam(rhs) {
 		check.error(tdecl.Type, MisplacedTypeParam, "cannot use a type parameter as RHS in type declaration")
-		named.underlying = Typ[Invalid]
+		named.fromRHS = Typ[Invalid]
 	}
 }
 
@@ -721,7 +726,7 @@ func (check *Checker) collectMethods(obj *TypeName) {
 }
 
 func (check *Checker) checkFieldUniqueness(base *Named) {
-	if t, _ := base.under().(*Struct); t != nil {
+	if t, _ := base.Underlying().(*Struct); t != nil {
 		var mset objset
 		for i := 0; i < base.NumMethods(); i++ {
 			m := base.Method(i)
diff --git a/src/cmd/compile/internal/types2/named.go b/src/cmd/compile/internal/types2/named.go
index d02b95e874a470..4a28929c513a9b 100644
--- a/src/cmd/compile/internal/types2/named.go
+++ b/src/cmd/compile/internal/types2/named.go
@@ -62,14 +62,14 @@ import (
 //  - We say that a Named type is "resolved" if its RHS information has been
 //    loaded or fully type-checked. For Named types constructed from export
 //    data, this may involve invoking a loader function to extract information
-//    from export data. For instantiated named types this involves reading
-//    information from their origin.
+//    from export data. For instantiated Named types this involves reading
+//    information from their origin and substituting type arguments into a
+//    "synthetic" RHS; this process is called "expanding" the RHS (see below).
 //  - We say that a Named type is "expanded" if it is an instantiated type and
-//    type parameters in its underlying type and methods have been substituted
-//    with the type arguments from the instantiation. A type may be partially
-//    expanded if some but not all of these details have been substituted.
-//    Similarly, we refer to these individual details (underlying type or
-//    method) as being "expanded".
+//    type parameters in its RHS and methods have been substituted with the type
+//    arguments from the instantiation. A type may be partially expanded if some
+//    but not all of these details have been substituted. Similarly, we refer to
+//    these individual details (RHS or method) as being "expanded".
 //  - When all information is known for a named type, we say it is "complete".
 //
 // Some invariants to keep in mind: each declared Named type has a single
@@ -107,18 +107,17 @@ type Named struct {
 	check *Checker  // non-nil during type-checking; nil otherwise
 	obj   *TypeName // corresponding declared object for declared types; see above for instantiated types
 
-	// fromRHS holds the type (on RHS of declaration) this *Named type is derived
-	// from (for cycle reporting). Only used by validType, and therefore does not
-	// require synchronization.
-	fromRHS Type
+	// flags indicating temporary violations of the invariants for fromRHS and underlying
+	allowNilRHS        bool // same as below, as well as briefly during checking of a type declaration
+	allowNilUnderlying bool // may be true from creation via [NewNamed] until [Named.SetUnderlying]
 
-	// information for instantiated types; nil otherwise
-	inst *instance
+	underlying Type      // underlying type, or nil
+	inst       *instance // information for instantiated types; nil otherwise
 
-	mu         sync.Mutex     // guards all fields below
-	state_     uint32         // the current state of this type; must only be accessed atomically
-	underlying Type           // possibly a *Named during setup; never a *Named once set up completely
-	tparams    *TypeParamList // type parameters, or nil
+	mu      sync.Mutex     // guards all fields below
+	state_  uint32         // the current state of this type; must only be accessed atomically
+	fromRHS Type           // the declaration RHS this type is derived from
+	tparams *TypeParamList // type parameters, or nil
 
 	// methods declared for this type (not the method set of this type)
 	// Signatures are type-checked lazily.
@@ -145,7 +144,7 @@ type namedState uint32
 
 // Note: the order of states is relevant
 const (
-	unresolved namedState = iota // tparams, underlying type and methods might be unavailable
+	unresolved namedState = iota // type parameters, RHS, underlying, and methods might be unavailable
 	resolved                     // resolve has run; methods might be unexpanded (for instances)
 	loaded                       // loader has run; constraints might be unexpanded (for generic types)
 	complete                     // all data is known
@@ -158,10 +157,18 @@ func NewNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
 	if asNamed(underlying) != nil {
 		panic("underlying type must not be *Named")
 	}
-	return (*Checker)(nil).newNamed(obj, underlying, methods)
+	n := (*Checker)(nil).newNamed(obj, underlying, methods)
+	if underlying == nil {
+		n.allowNilRHS = true
+		n.allowNilUnderlying = true
+	} else {
+		n.SetUnderlying(underlying)
+	}
+	return n
+
 }
 
-// resolve resolves the type parameters, methods, and underlying type of n.
+// resolve resolves the type parameters, methods, and RHS of n.
 //
 // For the purposes of resolution, there are three categories of named types:
 //  1. Instantiated Types
@@ -171,18 +178,17 @@ func NewNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
 // Note that the above form a partition.
 //
 // Instantiated types:
-// Type parameters, methods, and underlying type of n become accessible,
-// though methods are lazily populated as needed.
+// Type parameters, methods, and RHS of n become accessible, though methods
+// are lazily populated as needed.
 //
 // Lazy loaded types:
-// Type parameters, methods, and underlying type of n become accessible
-// and are fully expanded.
+// Type parameters, methods, and RHS of n become accessible and are fully
+// expanded.
 //
 // All others:
-// Effectively, nothing happens. The underlying type of n may still be
-// a named type.
+// Effectively, nothing happens.
 func (n *Named) resolve() *Named {
-	if n.state() > unresolved { // avoid locking below
+	if n.state() >= resolved { // avoid locking below
 		return n
 	}
 
@@ -191,21 +197,19 @@ func (n *Named) resolve() *Named {
 	n.mu.Lock()
 	defer n.mu.Unlock()
 
-	if n.state() > unresolved {
+	if n.state() >= resolved {
 		return n
 	}
 
 	if n.inst != nil {
-		assert(n.underlying == nil) // n is an unresolved instance
-		assert(n.loader == nil)     // instances are created by instantiation, in which case n.loader is nil
+		assert(n.fromRHS == nil) // instantiated types are not declared types
+		assert(n.loader == nil)  // cannot import an instantiation
 
 		orig := n.inst.orig
 		orig.resolve()
-		underlying := n.expandUnderlying()
 
+		n.fromRHS = n.expandRHS()
 		n.tparams = orig.tparams
-		n.underlying = underlying
-		n.fromRHS = orig.fromRHS // for cycle detection
 
 		if len(orig.methods) == 0 {
 			n.setState(complete) // nothing further to do
@@ -224,25 +228,25 @@ func (n *Named) resolve() *Named {
 	// methods would need to support reentrant calls though. It would
 	// also make the API more future-proof towards further extensions.
 	if n.loader != nil {
-		assert(n.underlying == nil)
-		assert(n.TypeArgs().Len() == 0) // instances are created by instantiation, in which case n.loader is nil
+		assert(n.fromRHS == nil) // not loaded yet
+		assert(n.inst == nil)    // cannot import an instantiation
 
 		tparams, underlying, methods, delayed := n.loader(n)
 		n.loader = nil
 
 		n.tparams = bindTParams(tparams)
-		n.underlying = underlying
 		n.fromRHS = underlying // for cycle detection
 		n.methods = methods
 
-		// advance state to avoid deadlock calling delayed functions
-		n.setState(loaded)
+		n.setState(loaded) // avoid deadlock calling delayed functions
 
 		for _, f := range delayed {
 			f()
 		}
 	}
 
+	assert(n.fromRHS != nil || n.allowNilRHS)
+	assert(n.underlying == nil) // underlying comes after resolving
 	n.setState(complete)
 	return n
 }
@@ -259,8 +263,8 @@ func (n *Named) setState(state namedState) {
 }
 
 // newNamed is like NewNamed but with a *Checker receiver.
-func (check *Checker) newNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
-	typ := &Named{check: check, obj: obj, fromRHS: underlying, underlying: underlying, methods: methods}
+func (check *Checker) newNamed(obj *TypeName, fromRHS Type, methods []*Func) *Named {
+	typ := &Named{check: check, obj: obj, fromRHS: fromRHS, methods: methods}
 	if obj.typ == nil {
 		obj.typ = typ
 	}
@@ -300,25 +304,13 @@ func (check *Checker) newNamedInstance(pos syntax.Pos, orig *Named, targs []Type
 	return typ
 }
 
-func (t *Named) cleanup() {
-	assert(t.inst == nil || t.inst.orig.inst == nil)
-	// Ensure that every defined type created in the course of type-checking has
-	// either non-*Named underlying type, or is unexpanded.
-	//
-	// This guarantees that we don't leak any types whose underlying type is
-	// *Named, because any unexpanded instances will lazily compute their
-	// underlying type by substituting in the underlying type of their origin.
-	// The origin must have either been imported or type-checked and expanded
-	// here, and in either case its underlying type will be fully expanded.
-	switch t.underlying.(type) {
-	case nil:
-		if t.TypeArgs().Len() == 0 {
-			panic("nil underlying")
-		}
-	case *Named, *Alias:
-		t.under() // t.under may add entries to check.cleaners
+func (n *Named) cleanup() {
+	// Instances can have a nil underlying at the end of type checking — they
+	// will lazily expand it as needed. All other types must have one.
+	if n.inst == nil {
+		n.resolve().under()
 	}
-	t.check = nil
+	n.check = nil
 }
 
 // Obj returns the type name for the declaration defining the named type t. For
@@ -477,10 +469,12 @@ func (t *Named) SetUnderlying(underlying Type) {
 	if asNamed(underlying) != nil {
 		panic("underlying type must not be *Named")
 	}
-	t.resolve().underlying = underlying
-	if t.fromRHS == nil {
-		t.fromRHS = underlying // for cycle detection
-	}
+	// Invariant: Presence of underlying type implies it was resolved.
+	t.fromRHS = underlying
+	t.allowNilRHS = false
+	t.resolve()
+	t.underlying = underlying
+	t.allowNilUnderlying = false
 }
 
 // AddMethod adds method m unless it is already in the method list.
@@ -523,9 +517,20 @@ func (t *Named) methodIndex(name string, foldCase bool) int {
 // Alias types.
 //
 // [underlying type]: https://go.dev/ref/spec#Underlying_types.
-func (t *Named) Underlying() Type {
-	// TODO(gri) Investigate if Unalias can be moved to where underlying is set.
-	return Unalias(t.resolve().underlying)
+func (n *Named) Underlying() Type {
+	n.resolve()
+
+	// The gccimporter depends on writing a nil underlying via NewNamed and
+	// immediately reading it back. Rather than putting that in under() and
+	// complicating things there, we just check for that special case here.
+	if n.fromRHS == nil {
+		assert(n.allowNilRHS)
+		if n.allowNilUnderlying {
+			return nil
+		}
+	}
+
+	return n.under()
 }
 
 func (t *Named) String() string { return TypeString(t, nil) }
@@ -536,89 +541,55 @@ func (t *Named) String() string { return TypeString(t, nil) }
 // TODO(rfindley): reorganize the loading and expansion methods under this
 // heading.
 
-// under returns the expanded underlying type of n0; possibly by following
-// forward chains of named types. If an underlying type is found, resolve
-// the chain by setting the underlying type for each defined type in the
-// chain before returning it. If no underlying type is found or a cycle
-// is detected, the result is Typ[Invalid]. If a cycle is detected and
-// n0.check != nil, the cycle is reported.
-//
-// This is necessary because the underlying type of named may be itself a
-// named type that is incomplete:
-//
-//	type (
-//		A B
-//		B *C
-//		C A
-//	)
-//
-// The type of C is the (named) type of A which is incomplete,
-// and which has as its underlying type the named type B.
-func (n0 *Named) under() Type {
-	u := n0.Underlying()
-
-	// If the underlying type of a defined type is not a defined
-	// (incl. instance) type, then that is the desired underlying
-	// type.
-	var n1 *Named
-	switch u1 := u.(type) {
-	case nil:
-		// After expansion via Underlying(), we should never encounter a nil
-		// underlying.
-		panic("nil underlying")
-	default:
-		// common case
-		return u
-	case *Named:
-		// handled below
-		n1 = u1
-	}
-
-	if n0.check == nil {
-		panic("Named.check == nil but type is incomplete")
-	}
-
-	// Invariant: after this point n0 as well as any named types in its
-	// underlying chain should be set up when this function exits.
-	check := n0.check
-	n := n0
-
-	seen := make(map[*Named]int) // types that need their underlying type resolved
-	var path []Object            // objects encountered, for cycle reporting
-
-loop:
-	for {
-		seen[n] = len(seen)
-		path = append(path, n.obj)
-		n = n1
-		if i, ok := seen[n]; ok {
-			// cycle
-			check.cycleError(path[i:], firstInSrc(path[i:]))
-			u = Typ[Invalid]
-			break
-		}
-		u = n.Underlying()
-		switch u1 := u.(type) {
+// under returns the (possibly expanded) underlying type of n.
+//
+// It does so by following RHS type chains. If a type literal is found, each
+// named type in the chain has its underlying set to that type. Aliases are
+// skipped because their underlying type is not memoized.
+//
+// This function also checks for instantiated layout cycles, which are
+// reachable only in the case where resolve() expanded an instantiated
+// type which became self-referencing without indirection. If such a
+// cycle is found, the result is Typ[Invalid]; if n.check != nil, the
+// cycle is also reported.
+func (n *Named) under() Type {
+	assert(n.state() >= resolved)
+
+	if n.underlying != nil {
+		return n.underlying
+	}
+
+	var rhs Type = n
+	var u Type
+
+	seen := make(map[*Named]int)
+	var path []Object
+
+	for u == nil {
+		switch t := rhs.(type) {
 		case nil:
 			u = Typ[Invalid]
-			break loop
-		default:
-			break loop
+		case *Alias:
+			rhs = unalias(t)
 		case *Named:
-			// Continue collecting *Named types in the chain.
-			n1 = u1
+			if i, ok := seen[t]; ok {
+				n.check.cycleError(path[i:], firstInSrc(path[i:]))
+				u = Typ[Invalid]
+				break
+			}
+			seen[t] = len(seen)
+			path = append(path, t.obj)
+			t.resolve()
+			assert(t.fromRHS != nil || t.allowNilRHS)
+			rhs = t.fromRHS
+		default:
+			u = rhs // any type literal works
 		}
 	}
 
-	for n := range seen {
-		// We should never have to update the underlying type of an imported type;
-		// those underlying types should have been resolved during the import.
-		// Also, doing so would lead to a race condition (was go.dev/issue/31749).
-		// Do this check always, not just in debug mode (it's cheap).
-		if n.obj.pkg != check.pkg {
-			panic("imported type with unresolved underlying type")
-		}
-		n.underlying = u
+	// go back up the chain
+	for t := range seen {
+		t.underlying = u
 	}
 
 	return u
@@ -646,78 +617,108 @@ func (check *Checker) context() *Context {
 	return check.ctxt
 }
 
-// expandUnderlying substitutes type arguments in the underlying type n.orig,
-// returning the result. Returns Typ[Invalid] if there was an error.
-func (n *Named) expandUnderlying() Type {
+// expandRHS crafts a synthetic RHS for an instantiated type using the RHS of
+// its origin type (which must be a generic type).
+//
+// Suppose that we had:
+//
+//	type T[P any] struct {
+//	  f P
+//	}
+//
+//	type U T[int]
+//
+// When we go to U, we observe T[int]. Since T[int] is an instantiation, it has no
+// declaration. Here, we craft a synthetic RHS for T[int] as if it were declared,
+// somewhat similar to:
+//
+//	type T[int] struct {
+//	  f int
+//	}
+//
+// And note that the synthetic RHS here is the same as the underlying for U. Now,
+// consider:
+//
+//	type T[_ any] U
+//	type U int
+//	type V T[U]
+//
+// The synthetic RHS for T[U] becomes:
+//
+//	type T[U] U
+//
+// Whereas the underlying of V is int, not U.
+func (n *Named) expandRHS() (rhs Type) {
 	check := n.check
 	if check != nil && check.conf.Trace {
-		check.trace(n.obj.pos, "-- Named.expandUnderlying %s", n)
+		check.trace(n.obj.pos, "-- Named.expandRHS %s", n)
 		check.indent++
 		defer func() {
 			check.indent--
-			check.trace(n.obj.pos, "=> %s (tparams = %s, under = %s)", n, n.tparams.list(), n.underlying)
+			check.trace(n.obj.pos, "=> %s (rhs = %s)", n, rhs)
 		}()
 	}
 
-	assert(n.inst.orig.underlying != nil)
+	assert(n.state() == unresolved)
+
 	if n.inst.ctxt == nil {
 		n.inst.ctxt = NewContext()
 	}
 
+	ctxt := n.inst.ctxt
 	orig := n.inst.orig
-	targs := n.inst.targs
 
-	if asNamed(orig.underlying) != nil {
-		// We should only get a Named underlying type here during type checking
-		// (for example, in recursive type declarations).
-		assert(check != nil)
-	}
+	assert(orig.state() >= resolved)
+	assert(orig.fromRHS != nil)
+
+	targs := n.inst.targs
+	tpars := orig.tparams
 
-	if orig.tparams.Len() != targs.Len() {
-		// Mismatching arg and tparam length may be checked elsewhere.
+	if targs.Len() != tpars.Len() {
 		return Typ[Invalid]
 	}
 
-	// Ensure that an instance is recorded before substituting, so that we
-	// resolve n for any recursive references.
-	h := n.inst.ctxt.instanceHash(orig, targs.list())
-	n2 := n.inst.ctxt.update(h, orig, n.TypeArgs().list(), n)
-	assert(n == n2)
+	h := ctxt.instanceHash(orig, targs.list())
+	u := ctxt.update(h, orig, targs.list(), n) // block fixed point infinite instantiation
+	assert(n == u)
 
-	smap := makeSubstMap(orig.tparams.list(), targs.list())
-	var ctxt *Context
+	m := makeSubstMap(tpars.list(), targs.list())
 	if check != nil {
 		ctxt = check.context()
 	}
-	underlying := n.check.subst(n.obj.pos, orig.underlying, smap, n, ctxt)
-	// If the underlying type of n is an interface, we need to set the receiver of
-	// its methods accurately -- we set the receiver of interface methods on
-	// the RHS of a type declaration to the defined type.
-	if iface, _ := underlying.(*Interface); iface != nil {
+
+	rhs = check.subst(n.obj.pos, orig.fromRHS, m, n, ctxt)
+
+	// TODO(markfreeman): Can we handle this in substitution?
+	// If the RHS is an interface, we must set the receiver of interface methods
+	// to the named type.
+	if iface, _ := rhs.(*Interface); iface != nil {
 		if methods, copied := replaceRecvType(iface.methods, orig, n); copied {
-			// If the underlying type doesn't actually use type parameters, it's
-			// possible that it wasn't substituted. In this case we need to create
-			// a new *Interface before modifying receivers.
-			if iface == orig.underlying {
-				old := iface
-				iface = check.newInterface()
-				iface.embeddeds = old.embeddeds
-				assert(old.complete) // otherwise we are copying incomplete data
-				iface.complete = old.complete
-				iface.implicit = old.implicit // should be false but be conservative
-				underlying = iface
+			// If the RHS doesn't use type parameters, it may not have been
+			// substituted; we need to craft a new interface first.
+			if iface == orig.fromRHS {
+				assert(iface.complete) // otherwise we are copying incomplete data
+
+				crafted := check.newInterface()
+				crafted.complete = true
+				crafted.implicit = false
+				crafted.embeddeds = iface.embeddeds
+
+				iface = crafted
 			}
 			iface.methods = methods
 			iface.tset = nil // recompute type set with new methods
 
-			// If check != nil, check.newInterface will have saved the interface for later completion.
-			if check == nil { // golang/go#61561: all newly created interfaces must be fully evaluated
+			// go.dev/issue/61561: We have to complete the interface even without a checker.
+			if check == nil {
 				iface.typeSet()
 			}
+
+			return iface
 		}
 	}
 
-	return underlying
+	return rhs
 }
 
 // safeUnderlying returns the underlying type of typ without expanding
diff --git a/src/cmd/compile/internal/types2/object.go b/src/cmd/compile/internal/types2/object.go
index 7096c556971077..6331259e1767f5 100644
--- a/src/cmd/compile/internal/types2/object.go
+++ b/src/cmd/compile/internal/types2/object.go
@@ -295,7 +295,8 @@ func NewTypeName(pos syntax.Pos, pkg *Package, name string, typ Type) *TypeName
 // lazily calls resolve to finish constructing the Named object.
 func NewTypeNameLazy(pos syntax.Pos, pkg *Package, name string, load func(*Named) ([]*TypeParam, Type, []*Func, []func())) *TypeName {
 	obj := NewTypeName(pos, pkg, name, nil)
-	NewNamed(obj, nil, nil).loader = load
+	n := (*Checker)(nil).newNamed(obj, nil, nil)
+	n.loader = load
 	return obj
 }
 
diff --git a/src/cmd/compile/internal/types2/signature.go b/src/cmd/compile/internal/types2/signature.go
index 1e004eef4aeda6..ea60254fa6832e 100644
--- a/src/cmd/compile/internal/types2/signature.go
+++ b/src/cmd/compile/internal/types2/signature.go
@@ -439,7 +439,7 @@ func (check *Checker) validRecv(pos poser, recv *Var) {
 			break
 		}
 		var cause string
-		switch u := T.under().(type) {
+		switch u := T.Underlying().(type) {
 		case *Basic:
 			// unsafe.Pointer is treated like a regular pointer
 			if u.kind == UnsafePointer {
diff --git a/src/cmd/compile/internal/types2/sizeof_test.go b/src/cmd/compile/internal/types2/sizeof_test.go
index d435c049c5b87d..13b96209114de1 100644
--- a/src/cmd/compile/internal/types2/sizeof_test.go
+++ b/src/cmd/compile/internal/types2/sizeof_test.go
@@ -31,7 +31,7 @@ func TestSizeof(t *testing.T) {
 		{Interface{}, 40, 80},
 		{Map{}, 16, 32},
 		{Chan{}, 12, 24},
-		{Named{}, 60, 112},
+		{Named{}, 64, 120},
 		{TypeParam{}, 28, 48},
 		{term{}, 12, 24},
 
diff --git a/src/cmd/compile/internal/types2/typexpr.go b/src/cmd/compile/internal/types2/typexpr.go
index 8accc46751fdd0..b1533de5048ae1 100644
--- a/src/cmd/compile/internal/types2/typexpr.go
+++ b/src/cmd/compile/internal/types2/typexpr.go
@@ -425,7 +425,7 @@ func setDefType(def *TypeName, typ Type) {
 		case *Basic:
 			assert(t == Typ[Invalid])
 		case *Named:
-			t.underlying = typ
+			t.fromRHS = typ
 		default:
 			panic(fmt.Sprintf("unexpected type %T", t))
 		}
diff --git a/src/cmd/compile/internal/types2/under.go b/src/cmd/compile/internal/types2/under.go
index 078ba9ab172453..8e9871eacd0d90 100644
--- a/src/cmd/compile/internal/types2/under.go
+++ b/src/cmd/compile/internal/types2/under.go
@@ -11,9 +11,7 @@ import "iter"
 // under must only be called when a type is known
 // to be fully set up.
 func under(t Type) Type {
-	if t := asNamed(t); t != nil {
-		return t.under()
-	}
+	// TODO(markfreeman): Remove this function, it just delegates.
 	return t.Underlying()
 }
 
diff --git a/src/cmd/compile/internal/types2/unify.go b/src/cmd/compile/internal/types2/unify.go
index 9cd3af8607181e..8e112248c635ab 100644
--- a/src/cmd/compile/internal/types2/unify.go
+++ b/src/cmd/compile/internal/types2/unify.go
@@ -339,7 +339,7 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
 		if traceInference {
 			u.tracef("%s ≡ under %s", x, ny)
 		}
-		y = ny.under()
+		y = ny.Underlying()
 		// Per the spec, a defined type cannot have an underlying type
 		// that is a type parameter.
 		assert(!isTypeParam(y))
diff --git a/src/cmd/compile/internal/types2/universe.go b/src/cmd/compile/internal/types2/universe.go
index c66caebd10cef7..332cd174f97466 100644
--- a/src/cmd/compile/internal/types2/universe.go
+++ b/src/cmd/compile/internal/types2/universe.go
@@ -116,7 +116,7 @@ func defPredeclaredTypes() {
 	{
 		obj := NewTypeName(nopos, nil, "error", nil)
 		obj.setColor(black)
-		typ := NewNamed(obj, nil, nil)
+		typ := (*Checker)(nil).newNamed(obj, nil, nil)
 
 		// error.Error() string
 		recv := newVar(RecvVar, nopos, nil, "", typ)
@@ -128,7 +128,8 @@ func defPredeclaredTypes() {
 		ityp := &Interface{methods: []*Func{err}, complete: true}
 		computeInterfaceTypeSet(nil, nopos, ityp) // prevent races due to lazy computation of tset
 
-		typ.SetUnderlying(ityp)
+		typ.fromRHS = ityp
+		typ.Underlying()
 		def(obj)
 	}
 
@@ -136,12 +137,13 @@ func defPredeclaredTypes() {
 	{
 		obj := NewTypeName(nopos, nil, "comparable", nil)
 		obj.setColor(black)
-		typ := NewNamed(obj, nil, nil)
+		typ := (*Checker)(nil).newNamed(obj, nil, nil)
 
 		// interface{} // marked as comparable
 		ityp := &Interface{complete: true, tset: &_TypeSet{nil, allTermlist, true}}
 
-		typ.SetUnderlying(ityp)
+		typ.fromRHS = ityp
+		typ.Underlying()
 		def(obj)
 	}
 }
diff --git a/src/cmd/compile/internal/types2/validtype.go b/src/cmd/compile/internal/types2/validtype.go
index 32e389a6562445..528f5121e392ee 100644
--- a/src/cmd/compile/internal/types2/validtype.go
+++ b/src/cmd/compile/internal/types2/validtype.go
@@ -91,13 +91,6 @@ func (check *Checker) validType0(pos syntax.Pos, typ Type, nest, path []*Named)
 		// 	break
 		// }
 
-		// Don't report a 2nd error if we already know the type is invalid
-		// (e.g., if a cycle was detected earlier, via under).
-		// Note: ensure that t.orig is fully resolved by calling Underlying().
-		if !isValid(t.Underlying()) {
-			return false
-		}
-
 		// If the current type t is also found in nest, (the memory of) t is
 		// embedded in itself, indicating an invalid recursive type.
 		for _, e := range nest {
@@ -125,8 +118,9 @@ func (check *Checker) validType0(pos syntax.Pos, typ Type, nest, path []*Named)
 				// are not yet available to other goroutines).
 				assert(t.obj.pkg == check.pkg)
 				assert(t.Origin().obj.pkg == check.pkg)
-				t.underlying = Typ[Invalid]
-				t.Origin().underlying = Typ[Invalid]
+
+				// let t become invalid when it resolves
+				t.Origin().fromRHS = Typ[Invalid]
 
 				// Find the starting point of the cycle and report it.
 				// Because each type in nest must also appear in path (see invariant below),
diff --git a/src/go/types/decl.go b/src/go/types/decl.go
index 13d9d9ce57499c..6e61dd9a131429 100644
--- a/src/go/types/decl.go
+++ b/src/go/types/decl.go
@@ -551,7 +551,7 @@ func (check *Checker) isImportedConstraint(typ Type) bool {
 	if named == nil || named.obj.pkg == check.pkg || named.obj.pkg == nil {
 		return false
 	}
-	u, _ := named.under().(*Interface)
+	u, _ := named.Underlying().(*Interface)
 	return u != nil && !u.IsMethodSet()
 }
 
@@ -640,28 +640,33 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *ast.TypeSpec, def *TypeName
 	named := check.newNamed(obj, nil, nil)
 	setDefType(def, named)
 
+	// The RHS of a named N can be nil if, for example, N is defined as a cycle of aliases with
+	// gotypesalias=0. Consider:
+	//
+	//   type D N    // N.resolve() will panic
+	//   type N A
+	//   type A = N  // N.fromRHS is not set before N.resolve(), since A does not call setDefType
+	//
+	// There is likely a better way to detect such cases, but it may not be worth the effort.
+	// Instead, we briefly permit a nil N.fromRHS while type-checking D.
+	named.allowNilRHS = true
+	defer (func() { named.allowNilRHS = false })()
+
 	if tdecl.TypeParams != nil {
 		check.openScope(tdecl, "type parameters")
 		defer check.closeScope()
 		check.collectTypeParams(&named.tparams, tdecl.TypeParams)
 	}
 
-	// determine underlying type of named
 	rhs = check.definedType(tdecl.Type, obj)
 	assert(rhs != nil)
 	named.fromRHS = rhs
 
-	// If the underlying type was not set while type-checking the right-hand
-	// side, it is invalid and an error should have been reported elsewhere.
-	if named.underlying == nil {
-		named.underlying = Typ[Invalid]
-	}
-
 	// spec: "In a type definition the given type cannot be a type parameter."
 	// (See also go.dev/issue/45639.)
 	if isTypeParam(rhs) {
 		check.error(tdecl.Type, MisplacedTypeParam, "cannot use a type parameter as RHS in type declaration")
-		named.underlying = Typ[Invalid]
+		named.fromRHS = Typ[Invalid]
 	}
 }
 
@@ -814,7 +819,7 @@ func (check *Checker) collectMethods(obj *TypeName) {
 }
 
 func (check *Checker) checkFieldUniqueness(base *Named) {
-	if t, _ := base.under().(*Struct); t != nil {
+	if t, _ := base.Underlying().(*Struct); t != nil {
 		var mset objset
 		for i := 0; i < base.NumMethods(); i++ {
 			m := base.Method(i)
diff --git a/src/go/types/named.go b/src/go/types/named.go
index b2f99ffccb9062..d7e4c2479634fc 100644
--- a/src/go/types/named.go
+++ b/src/go/types/named.go
@@ -65,14 +65,14 @@ import (
 //  - We say that a Named type is "resolved" if its RHS information has been
 //    loaded or fully type-checked. For Named types constructed from export
 //    data, this may involve invoking a loader function to extract information
-//    from export data. For instantiated named types this involves reading
-//    information from their origin.
+//    from export data. For instantiated Named types this involves reading
+//    information from their origin and substituting type arguments into a
+//    "synthetic" RHS; this process is called "expanding" the RHS (see below).
 //  - We say that a Named type is "expanded" if it is an instantiated type and
-//    type parameters in its underlying type and methods have been substituted
-//    with the type arguments from the instantiation. A type may be partially
-//    expanded if some but not all of these details have been substituted.
-//    Similarly, we refer to these individual details (underlying type or
-//    method) as being "expanded".
+//    type parameters in its RHS and methods have been substituted with the type
+//    arguments from the instantiation. A type may be partially expanded if some
+//    but not all of these details have been substituted. Similarly, we refer to
+//    these individual details (RHS or method) as being "expanded".
 //  - When all information is known for a named type, we say it is "complete".
 //
 // Some invariants to keep in mind: each declared Named type has a single
@@ -110,18 +110,17 @@ type Named struct {
 	check *Checker  // non-nil during type-checking; nil otherwise
 	obj   *TypeName // corresponding declared object for declared types; see above for instantiated types
 
-	// fromRHS holds the type (on RHS of declaration) this *Named type is derived
-	// from (for cycle reporting). Only used by validType, and therefore does not
-	// require synchronization.
-	fromRHS Type
+	// flags indicating temporary violations of the invariants for fromRHS and underlying
+	allowNilRHS        bool // same as below, as well as briefly during checking of a type declaration
+	allowNilUnderlying bool // may be true from creation via [NewNamed] until [Named.SetUnderlying]
 
-	// information for instantiated types; nil otherwise
-	inst *instance
+	underlying Type      // underlying type, or nil
+	inst       *instance // information for instantiated types; nil otherwise
 
-	mu         sync.Mutex     // guards all fields below
-	state_     uint32         // the current state of this type; must only be accessed atomically
-	underlying Type           // possibly a *Named during setup; never a *Named once set up completely
-	tparams    *TypeParamList // type parameters, or nil
+	mu      sync.Mutex     // guards all fields below
+	state_  uint32         // the current state of this type; must only be accessed atomically
+	fromRHS Type           // the declaration RHS this type is derived from
+	tparams *TypeParamList // type parameters, or nil
 
 	// methods declared for this type (not the method set of this type)
 	// Signatures are type-checked lazily.
@@ -148,7 +147,7 @@ type namedState uint32
 
 // Note: the order of states is relevant
 const (
-	unresolved namedState = iota // tparams, underlying type and methods might be unavailable
+	unresolved namedState = iota // type parameters, RHS, underlying, and methods might be unavailable
 	resolved                     // resolve has run; methods might be unexpanded (for instances)
 	loaded                       // loader has run; constraints might be unexpanded (for generic types)
 	complete                     // all data is known
@@ -161,10 +160,18 @@ func NewNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
 	if asNamed(underlying) != nil {
 		panic("underlying type must not be *Named")
 	}
-	return (*Checker)(nil).newNamed(obj, underlying, methods)
+	n := (*Checker)(nil).newNamed(obj, underlying, methods)
+	if underlying == nil {
+		n.allowNilRHS = true
+		n.allowNilUnderlying = true
+	} else {
+		n.SetUnderlying(underlying)
+	}
+	return n
+
 }
 
-// resolve resolves the type parameters, methods, and underlying type of n.
+// resolve resolves the type parameters, methods, and RHS of n.
 //
 // For the purposes of resolution, there are three categories of named types:
 //  1. Instantiated Types
@@ -174,18 +181,17 @@ func NewNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
 // Note that the above form a partition.
 //
 // Instantiated types:
-// Type parameters, methods, and underlying type of n become accessible,
-// though methods are lazily populated as needed.
+// Type parameters, methods, and RHS of n become accessible, though methods
+// are lazily populated as needed.
 //
 // Lazy loaded types:
-// Type parameters, methods, and underlying type of n become accessible
-// and are fully expanded.
+// Type parameters, methods, and RHS of n become accessible and are fully
+// expanded.
 //
 // All others:
-// Effectively, nothing happens. The underlying type of n may still be
-// a named type.
+// Effectively, nothing happens.
 func (n *Named) resolve() *Named {
-	if n.state() > unresolved { // avoid locking below
+	if n.state() >= resolved { // avoid locking below
 		return n
 	}
 
@@ -194,21 +200,19 @@ func (n *Named) resolve() *Named {
 	n.mu.Lock()
 	defer n.mu.Unlock()
 
-	if n.state() > unresolved {
+	if n.state() >= resolved {
 		return n
 	}
 
 	if n.inst != nil {
-		assert(n.underlying == nil) // n is an unresolved instance
-		assert(n.loader == nil)     // instances are created by instantiation, in which case n.loader is nil
+		assert(n.fromRHS == nil) // instantiated types are not declared types
+		assert(n.loader == nil)  // cannot import an instantiation
 
 		orig := n.inst.orig
 		orig.resolve()
-		underlying := n.expandUnderlying()
 
+		n.fromRHS = n.expandRHS()
 		n.tparams = orig.tparams
-		n.underlying = underlying
-		n.fromRHS = orig.fromRHS // for cycle detection
 
 		if len(orig.methods) == 0 {
 			n.setState(complete) // nothing further to do
@@ -227,25 +231,25 @@ func (n *Named) resolve() *Named {
 	// methods would need to support reentrant calls though. It would
 	// also make the API more future-proof towards further extensions.
 	if n.loader != nil {
-		assert(n.underlying == nil)
-		assert(n.TypeArgs().Len() == 0) // instances are created by instantiation, in which case n.loader is nil
+		assert(n.fromRHS == nil) // not loaded yet
+		assert(n.inst == nil)    // cannot import an instantiation
 
 		tparams, underlying, methods, delayed := n.loader(n)
 		n.loader = nil
 
 		n.tparams = bindTParams(tparams)
-		n.underlying = underlying
 		n.fromRHS = underlying // for cycle detection
 		n.methods = methods
 
-		// advance state to avoid deadlock calling delayed functions
-		n.setState(loaded)
+		n.setState(loaded) // avoid deadlock calling delayed functions
 
 		for _, f := range delayed {
 			f()
 		}
 	}
 
+	assert(n.fromRHS != nil || n.allowNilRHS)
+	assert(n.underlying == nil) // underlying comes after resolving
 	n.setState(complete)
 	return n
 }
@@ -262,8 +266,8 @@ func (n *Named) setState(state namedState) {
 }
 
 // newNamed is like NewNamed but with a *Checker receiver.
-func (check *Checker) newNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
-	typ := &Named{check: check, obj: obj, fromRHS: underlying, underlying: underlying, methods: methods}
+func (check *Checker) newNamed(obj *TypeName, fromRHS Type, methods []*Func) *Named {
+	typ := &Named{check: check, obj: obj, fromRHS: fromRHS, methods: methods}
 	if obj.typ == nil {
 		obj.typ = typ
 	}
@@ -303,25 +307,13 @@ func (check *Checker) newNamedInstance(pos token.Pos, orig *Named, targs []Type,
 	return typ
 }
 
-func (t *Named) cleanup() {
-	assert(t.inst == nil || t.inst.orig.inst == nil)
-	// Ensure that every defined type created in the course of type-checking has
-	// either non-*Named underlying type, or is unexpanded.
-	//
-	// This guarantees that we don't leak any types whose underlying type is
-	// *Named, because any unexpanded instances will lazily compute their
-	// underlying type by substituting in the underlying type of their origin.
-	// The origin must have either been imported or type-checked and expanded
-	// here, and in either case its underlying type will be fully expanded.
-	switch t.underlying.(type) {
-	case nil:
-		if t.TypeArgs().Len() == 0 {
-			panic("nil underlying")
-		}
-	case *Named, *Alias:
-		t.under() // t.under may add entries to check.cleaners
+func (n *Named) cleanup() {
+	// Instances can have a nil underlying at the end of type checking — they
+	// will lazily expand it as needed. All other types must have one.
+	if n.inst == nil {
+		n.resolve().under()
 	}
-	t.check = nil
+	n.check = nil
 }
 
 // Obj returns the type name for the declaration defining the named type t. For
@@ -480,10 +472,12 @@ func (t *Named) SetUnderlying(underlying Type) {
 	if asNamed(underlying) != nil {
 		panic("underlying type must not be *Named")
 	}
-	t.resolve().underlying = underlying
-	if t.fromRHS == nil {
-		t.fromRHS = underlying // for cycle detection
-	}
+	// Invariant: Presence of underlying type implies it was resolved.
+	t.fromRHS = underlying
+	t.allowNilRHS = false
+	t.resolve()
+	t.underlying = underlying
+	t.allowNilUnderlying = false
 }
 
 // AddMethod adds method m unless it is already in the method list.
@@ -526,9 +520,20 @@ func (t *Named) methodIndex(name string, foldCase bool) int {
 // Alias types.
 //
 // [underlying type]: https://go.dev/ref/spec#Underlying_types.
-func (t *Named) Underlying() Type {
-	// TODO(gri) Investigate if Unalias can be moved to where underlying is set.
-	return Unalias(t.resolve().underlying)
+func (n *Named) Underlying() Type {
+	n.resolve()
+
+	// The gccimporter depends on writing a nil underlying via NewNamed and
+	// immediately reading it back. Rather than putting that in under() and
+	// complicating things there, we just check for that special case here.
+	if n.fromRHS == nil {
+		assert(n.allowNilRHS)
+		if n.allowNilUnderlying {
+			return nil
+		}
+	}
+
+	return n.under()
 }
 
 func (t *Named) String() string { return TypeString(t, nil) }
@@ -539,89 +544,55 @@ func (t *Named) String() string { return TypeString(t, nil) }
 // TODO(rfindley): reorganize the loading and expansion methods under this
 // heading.
 
-// under returns the expanded underlying type of n0; possibly by following
-// forward chains of named types. If an underlying type is found, resolve
-// the chain by setting the underlying type for each defined type in the
-// chain before returning it. If no underlying type is found or a cycle
-// is detected, the result is Typ[Invalid]. If a cycle is detected and
-// n0.check != nil, the cycle is reported.
-//
-// This is necessary because the underlying type of named may be itself a
-// named type that is incomplete:
-//
-//	type (
-//		A B
-//		B *C
-//		C A
-//	)
-//
-// The type of C is the (named) type of A which is incomplete,
-// and which has as its underlying type the named type B.
-func (n0 *Named) under() Type {
-	u := n0.Underlying()
-
-	// If the underlying type of a defined type is not a defined
-	// (incl. instance) type, then that is the desired underlying
-	// type.
-	var n1 *Named
-	switch u1 := u.(type) {
-	case nil:
-		// After expansion via Underlying(), we should never encounter a nil
-		// underlying.
-		panic("nil underlying")
-	default:
-		// common case
-		return u
-	case *Named:
-		// handled below
-		n1 = u1
-	}
-
-	if n0.check == nil {
-		panic("Named.check == nil but type is incomplete")
-	}
-
-	// Invariant: after this point n0 as well as any named types in its
-	// underlying chain should be set up when this function exits.
-	check := n0.check
-	n := n0
-
-	seen := make(map[*Named]int) // types that need their underlying type resolved
-	var path []Object            // objects encountered, for cycle reporting
-
-loop:
-	for {
-		seen[n] = len(seen)
-		path = append(path, n.obj)
-		n = n1
-		if i, ok := seen[n]; ok {
-			// cycle
-			check.cycleError(path[i:], firstInSrc(path[i:]))
-			u = Typ[Invalid]
-			break
-		}
-		u = n.Underlying()
-		switch u1 := u.(type) {
+// under returns the (possibly expanded) underlying type of n.
+//
+// It does so by following RHS type chains. If a type literal is found, each
+// named type in the chain has its underlying set to that type. Aliases are
+// skipped because their underlying type is not memoized.
+//
+// This function also checks for instantiated layout cycles, which are
+// reachable only in the case where resolve() expanded an instantiated
+// type which became self-referencing without indirection. If such a
+// cycle is found, the result is Typ[Invalid]; if n.check != nil, the
+// cycle is also reported.
+func (n *Named) under() Type {
+	assert(n.state() >= resolved)
+
+	if n.underlying != nil {
+		return n.underlying
+	}
+
+	var rhs Type = n
+	var u Type
+
+	seen := make(map[*Named]int)
+	var path []Object
+
+	for u == nil {
+		switch t := rhs.(type) {
 		case nil:
 			u = Typ[Invalid]
-			break loop
-		default:
-			break loop
+		case *Alias:
+			rhs = unalias(t)
 		case *Named:
-			// Continue collecting *Named types in the chain.
-			n1 = u1
+			if i, ok := seen[t]; ok {
+				n.check.cycleError(path[i:], firstInSrc(path[i:]))
+				u = Typ[Invalid]
+				break
+			}
+			seen[t] = len(seen)
+			path = append(path, t.obj)
+			t.resolve()
+			assert(t.fromRHS != nil || t.allowNilRHS)
+			rhs = t.fromRHS
+		default:
+			u = rhs // any type literal works
 		}
 	}
 
-	for n := range seen {
-		// We should never have to update the underlying type of an imported type;
-		// those underlying types should have been resolved during the import.
-		// Also, doing so would lead to a race condition (was go.dev/issue/31749).
-		// Do this check always, not just in debug mode (it's cheap).
-		if n.obj.pkg != check.pkg {
-			panic("imported type with unresolved underlying type")
-		}
-		n.underlying = u
+	// go back up the chain
+	for t := range seen {
+		t.underlying = u
 	}
 
 	return u
@@ -649,78 +620,108 @@ func (check *Checker) context() *Context {
 	return check.ctxt
 }
 
-// expandUnderlying substitutes type arguments in the underlying type n.orig,
-// returning the result. Returns Typ[Invalid] if there was an error.
-func (n *Named) expandUnderlying() Type {
+// expandRHS crafts a synthetic RHS for an instantiated type using the RHS of
+// its origin type (which must be a generic type).
+//
+// Suppose that we had:
+//
+//	type T[P any] struct {
+//	  f P
+//	}
+//
+//	type U T[int]
+//
+// When we go to U, we observe T[int]. Since T[int] is an instantiation, it has no
+// declaration. Here, we craft a synthetic RHS for T[int] as if it were declared,
+// somewhat similar to:
+//
+//	type T[int] struct {
+//	  f int
+//	}
+//
+// And note that the synthetic RHS here is the same as the underlying for U. Now,
+// consider:
+//
+//	type T[_ any] U
+//	type U int
+//	type V T[U]
+//
+// The synthetic RHS for T[U] becomes:
+//
+//	type T[U] U
+//
+// Whereas the underlying of V is int, not U.
+func (n *Named) expandRHS() (rhs Type) {
 	check := n.check
 	if check != nil && check.conf._Trace {
-		check.trace(n.obj.pos, "-- Named.expandUnderlying %s", n)
+		check.trace(n.obj.pos, "-- Named.expandRHS %s", n)
 		check.indent++
 		defer func() {
 			check.indent--
-			check.trace(n.obj.pos, "=> %s (tparams = %s, under = %s)", n, n.tparams.list(), n.underlying)
+			check.trace(n.obj.pos, "=> %s (rhs = %s)", n, rhs)
 		}()
 	}
 
-	assert(n.inst.orig.underlying != nil)
+	assert(n.state() == unresolved)
+
 	if n.inst.ctxt == nil {
 		n.inst.ctxt = NewContext()
 	}
 
+	ctxt := n.inst.ctxt
 	orig := n.inst.orig
-	targs := n.inst.targs
 
-	if asNamed(orig.underlying) != nil {
-		// We should only get a Named underlying type here during type checking
-		// (for example, in recursive type declarations).
-		assert(check != nil)
-	}
+	assert(orig.state() >= resolved)
+	assert(orig.fromRHS != nil)
+
+	targs := n.inst.targs
+	tpars := orig.tparams
 
-	if orig.tparams.Len() != targs.Len() {
-		// Mismatching arg and tparam length may be checked elsewhere.
+	if targs.Len() != tpars.Len() {
 		return Typ[Invalid]
 	}
 
-	// Ensure that an instance is recorded before substituting, so that we
-	// resolve n for any recursive references.
-	h := n.inst.ctxt.instanceHash(orig, targs.list())
-	n2 := n.inst.ctxt.update(h, orig, n.TypeArgs().list(), n)
-	assert(n == n2)
+	h := ctxt.instanceHash(orig, targs.list())
+	u := ctxt.update(h, orig, targs.list(), n) // block fixed point infinite instantiation
+	assert(n == u)
 
-	smap := makeSubstMap(orig.tparams.list(), targs.list())
-	var ctxt *Context
+	m := makeSubstMap(tpars.list(), targs.list())
 	if check != nil {
 		ctxt = check.context()
 	}
-	underlying := n.check.subst(n.obj.pos, orig.underlying, smap, n, ctxt)
-	// If the underlying type of n is an interface, we need to set the receiver of
-	// its methods accurately -- we set the receiver of interface methods on
-	// the RHS of a type declaration to the defined type.
-	if iface, _ := underlying.(*Interface); iface != nil {
+
+	rhs = check.subst(n.obj.pos, orig.fromRHS, m, n, ctxt)
+
+	// TODO(markfreeman): Can we handle this in substitution?
+	// If the RHS is an interface, we must set the receiver of interface methods
+	// to the named type.
+	if iface, _ := rhs.(*Interface); iface != nil {
 		if methods, copied := replaceRecvType(iface.methods, orig, n); copied {
-			// If the underlying type doesn't actually use type parameters, it's
-			// possible that it wasn't substituted. In this case we need to create
-			// a new *Interface before modifying receivers.
-			if iface == orig.underlying {
-				old := iface
-				iface = check.newInterface()
-				iface.embeddeds = old.embeddeds
-				assert(old.complete) // otherwise we are copying incomplete data
-				iface.complete = old.complete
-				iface.implicit = old.implicit // should be false but be conservative
-				underlying = iface
+			// If the RHS doesn't use type parameters, it may not have been
+			// substituted; we need to craft a new interface first.
+			if iface == orig.fromRHS {
+				assert(iface.complete) // otherwise we are copying incomplete data
+
+				crafted := check.newInterface()
+				crafted.complete = true
+				crafted.implicit = false
+				crafted.embeddeds = iface.embeddeds
+
+				iface = crafted
 			}
 			iface.methods = methods
 			iface.tset = nil // recompute type set with new methods
 
-			// If check != nil, check.newInterface will have saved the interface for later completion.
-			if check == nil { // golang/go#61561: all newly created interfaces must be fully evaluated
+			// go.dev/issue/61561: We have to complete the interface even without a checker.
+			if check == nil {
 				iface.typeSet()
 			}
+
+			return iface
 		}
 	}
 
-	return underlying
+	return rhs
 }
 
 // safeUnderlying returns the underlying type of typ without expanding
diff --git a/src/go/types/object.go b/src/go/types/object.go
index 823c03c7fd94ce..305471222c5ccc 100644
--- a/src/go/types/object.go
+++ b/src/go/types/object.go
@@ -298,7 +298,8 @@ func NewTypeName(pos token.Pos, pkg *Package, name string, typ Type) *TypeName {
 // lazily calls resolve to finish constructing the Named object.
 func _NewTypeNameLazy(pos token.Pos, pkg *Package, name string, load func(*Named) ([]*TypeParam, Type, []*Func, []func())) *TypeName {
 	obj := NewTypeName(pos, pkg, name, nil)
-	NewNamed(obj, nil, nil).loader = load
+	n := (*Checker)(nil).newNamed(obj, nil, nil)
+	n.loader = load
 	return obj
 }
 
diff --git a/src/go/types/signature.go b/src/go/types/signature.go
index 972de97b1a1762..2f8be54e17177c 100644
--- a/src/go/types/signature.go
+++ b/src/go/types/signature.go
@@ -461,7 +461,7 @@ func (check *Checker) validRecv(pos positioner, recv *Var) {
 			break
 		}
 		var cause string
-		switch u := T.under().(type) {
+		switch u := T.Underlying().(type) {
 		case *Basic:
 			// unsafe.Pointer is treated like a regular pointer
 			if u.kind == UnsafePointer {
diff --git a/src/go/types/sizeof_test.go b/src/go/types/sizeof_test.go
index fa07eb10f1907c..4ff255ffa027eb 100644
--- a/src/go/types/sizeof_test.go
+++ b/src/go/types/sizeof_test.go
@@ -30,7 +30,7 @@ func TestSizeof(t *testing.T) {
 		{Interface{}, 40, 80},
 		{Map{}, 16, 32},
 		{Chan{}, 12, 24},
-		{Named{}, 60, 112},
+		{Named{}, 64, 120},
 		{TypeParam{}, 28, 48},
 		{term{}, 12, 24},
 
diff --git a/src/go/types/typexpr.go b/src/go/types/typexpr.go
index c040ee2a29cf82..2e45b7570f3677 100644
--- a/src/go/types/typexpr.go
+++ b/src/go/types/typexpr.go
@@ -421,7 +421,7 @@ func setDefType(def *TypeName, typ Type) {
 		case *Basic:
 			assert(t == Typ[Invalid])
 		case *Named:
-			t.underlying = typ
+			t.fromRHS = typ
 		default:
 			panic(fmt.Sprintf("unexpected type %T", t))
 		}
diff --git a/src/go/types/under.go b/src/go/types/under.go
index 43bf0ad07cd25f..d5e476a79f4739 100644
--- a/src/go/types/under.go
+++ b/src/go/types/under.go
@@ -14,9 +14,7 @@ import "iter"
 // under must only be called when a type is known
 // to be fully set up.
 func under(t Type) Type {
-	if t := asNamed(t); t != nil {
-		return t.under()
-	}
+	// TODO(markfreeman): Remove this function, it just delegates.
 	return t.Underlying()
 }
 
diff --git a/src/go/types/unify.go b/src/go/types/unify.go
index abcbab433a1bd1..2e3ba512df70c9 100644
--- a/src/go/types/unify.go
+++ b/src/go/types/unify.go
@@ -342,7 +342,7 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
 		if traceInference {
 			u.tracef("%s ≡ under %s", x, ny)
 		}
-		y = ny.under()
+		y = ny.Underlying()
 		// Per the spec, a defined type cannot have an underlying type
 		// that is a type parameter.
 		assert(!isTypeParam(y))
diff --git a/src/go/types/universe.go b/src/go/types/universe.go
index 4753111c118108..70935dc35ff4be 100644
--- a/src/go/types/universe.go
+++ b/src/go/types/universe.go
@@ -119,7 +119,7 @@ func defPredeclaredTypes() {
 	{
 		obj := NewTypeName(nopos, nil, "error", nil)
 		obj.setColor(black)
-		typ := NewNamed(obj, nil, nil)
+		typ := (*Checker)(nil).newNamed(obj, nil, nil)
 
 		// error.Error() string
 		recv := newVar(RecvVar, nopos, nil, "", typ)
@@ -131,7 +131,8 @@ func defPredeclaredTypes() {
 		ityp := &Interface{methods: []*Func{err}, complete: true}
 		computeInterfaceTypeSet(nil, nopos, ityp) // prevent races due to lazy computation of tset
 
-		typ.SetUnderlying(ityp)
+		typ.fromRHS = ityp
+		typ.Underlying()
 		def(obj)
 	}
 
@@ -139,12 +140,13 @@ func defPredeclaredTypes() {
 	{
 		obj := NewTypeName(nopos, nil, "comparable", nil)
 		obj.setColor(black)
-		typ := NewNamed(obj, nil, nil)
+		typ := (*Checker)(nil).newNamed(obj, nil, nil)
 
 		// interface{} // marked as comparable
 		ityp := &Interface{complete: true, tset: &_TypeSet{nil, allTermlist, true}}
 
-		typ.SetUnderlying(ityp)
+		typ.fromRHS = ityp
+		typ.Underlying()
 		def(obj)
 	}
 }
diff --git a/src/go/types/validtype.go b/src/go/types/validtype.go
index f87b82c439ebc3..578dcba1f97f3b 100644
--- a/src/go/types/validtype.go
+++ b/src/go/types/validtype.go
@@ -94,13 +94,6 @@ func (check *Checker) validType0(pos token.Pos, typ Type, nest, path []*Named) b
 		// 	break
 		// }
 
-		// Don't report a 2nd error if we already know the type is invalid
-		// (e.g., if a cycle was detected earlier, via under).
-		// Note: ensure that t.orig is fully resolved by calling Underlying().
-		if !isValid(t.Underlying()) {
-			return false
-		}
-
 		// If the current type t is also found in nest, (the memory of) t is
 		// embedded in itself, indicating an invalid recursive type.
 		for _, e := range nest {
@@ -128,8 +121,9 @@ func (check *Checker) validType0(pos token.Pos, typ Type, nest, path []*Named) b
 				// are not yet available to other goroutines).
 				assert(t.obj.pkg == check.pkg)
 				assert(t.Origin().obj.pkg == check.pkg)
-				t.underlying = Typ[Invalid]
-				t.Origin().underlying = Typ[Invalid]
+
+				// let t become invalid when it resolves
+				t.Origin().fromRHS = Typ[Invalid]
 
 				// Find the starting point of the cycle and report it.
 				// Because each type in nest must also appear in path (see invariant below),
diff --git a/src/internal/types/testdata/fixedbugs/issue75194.go b/src/internal/types/testdata/fixedbugs/issue75194.go
new file mode 100644
index 00000000000000..ec2f9249ec9247
--- /dev/null
+++ b/src/internal/types/testdata/fixedbugs/issue75194.go
@@ -0,0 +1,14 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+type A /* ERROR "invalid recursive type: A refers to itself" */ struct {
+	a A
+}
+
+type B /* ERROR "invalid recursive type: B refers to itself" */ struct {
+	a A
+	b B
+}

From 0c14000f87fc7f9d720a2937717d22b6c4f90e19 Mon Sep 17 00:00:00 2001
From: Mark Freeman 
Date: Thu, 16 Oct 2025 11:08:13 -0400
Subject: [PATCH 166/229] go/types, types2: remove under(Type) in favor of
 Type.Underlying()

As of CL 695977, under(Type) simply delegates to Type.Underlying().
This is just a cleanup.

Change-Id: I48d5fddc38560dfe485184faa6a5ff713bea74a0
Reviewed-on: https://go-review.googlesource.com/c/go/+/712400
Commit-Queue: Robert Griesemer 
Reviewed-by: Robert Griesemer 
Auto-Submit: Robert Griesemer 
LUCI-TryBot-Result: Go LUCI 
---
 .../compile/internal/types2/assignments.go    |  4 ++--
 src/cmd/compile/internal/types2/builtins.go   | 12 +++++------
 src/cmd/compile/internal/types2/call.go       |  4 ++--
 src/cmd/compile/internal/types2/const.go      |  2 +-
 .../compile/internal/types2/conversions.go    | 20 +++++++++----------
 src/cmd/compile/internal/types2/decl.go       |  2 +-
 src/cmd/compile/internal/types2/expr.go       | 10 +++++-----
 src/cmd/compile/internal/types2/gcsizes.go    |  4 ++--
 src/cmd/compile/internal/types2/index.go      | 12 +++++------
 src/cmd/compile/internal/types2/infer.go      |  2 +-
 .../compile/internal/types2/instantiate.go    |  8 ++++----
 src/cmd/compile/internal/types2/lookup.go     | 18 ++++++++---------
 src/cmd/compile/internal/types2/object.go     |  2 +-
 src/cmd/compile/internal/types2/operand.go    |  8 ++++----
 src/cmd/compile/internal/types2/predicates.go | 12 +++++------
 src/cmd/compile/internal/types2/range.go      |  2 +-
 src/cmd/compile/internal/types2/sizes.go      |  6 +++---
 src/cmd/compile/internal/types2/struct.go     |  4 ++--
 src/cmd/compile/internal/types2/typeparam.go  |  2 +-
 src/cmd/compile/internal/types2/typeset.go    | 10 +++++-----
 .../compile/internal/types2/typeset_test.go   |  2 +-
 src/cmd/compile/internal/types2/typestring.go |  2 +-
 src/cmd/compile/internal/types2/typeterm.go   |  6 +++---
 src/cmd/compile/internal/types2/typexpr.go    |  6 +++---
 src/cmd/compile/internal/types2/under.go      | 13 ++----------
 src/cmd/compile/internal/types2/unify.go      |  4 ++--
 src/cmd/compile/internal/types2/union.go      |  2 +-
 src/go/types/assignments.go                   |  4 ++--
 src/go/types/builtins.go                      | 12 +++++------
 src/go/types/call.go                          |  4 ++--
 src/go/types/const.go                         |  2 +-
 src/go/types/conversions.go                   | 20 +++++++++----------
 src/go/types/decl.go                          |  2 +-
 src/go/types/expr.go                          | 10 +++++-----
 src/go/types/gcsizes.go                       |  4 ++--
 src/go/types/index.go                         | 12 +++++------
 src/go/types/infer.go                         |  2 +-
 src/go/types/instantiate.go                   |  8 ++++----
 src/go/types/lookup.go                        | 18 ++++++++---------
 src/go/types/methodset.go                     |  2 +-
 src/go/types/object.go                        |  2 +-
 src/go/types/operand.go                       |  8 ++++----
 src/go/types/predicates.go                    | 12 +++++------
 src/go/types/range.go                         |  2 +-
 src/go/types/sizes.go                         |  6 +++---
 src/go/types/struct.go                        |  4 ++--
 src/go/types/typeparam.go                     |  2 +-
 src/go/types/typeset.go                       | 10 +++++-----
 src/go/types/typeset_test.go                  |  2 +-
 src/go/types/typestring.go                    |  2 +-
 src/go/types/typeterm.go                      |  6 +++---
 src/go/types/typexpr.go                       |  6 +++---
 src/go/types/under.go                         | 13 ++----------
 src/go/types/unify.go                         |  4 ++--
 src/go/types/union.go                         |  2 +-
 55 files changed, 171 insertions(+), 189 deletions(-)

diff --git a/src/cmd/compile/internal/types2/assignments.go b/src/cmd/compile/internal/types2/assignments.go
index 8af5f4037a5e3e..87f5c8beeafcaf 100644
--- a/src/cmd/compile/internal/types2/assignments.go
+++ b/src/cmd/compile/internal/types2/assignments.go
@@ -91,7 +91,7 @@ func (check *Checker) assignment(x *operand, T Type, context string) {
 	// x.typ is typed
 
 	// A generic (non-instantiated) function value cannot be assigned to a variable.
-	if sig, _ := under(x.typ).(*Signature); sig != nil && sig.TypeParams().Len() > 0 {
+	if sig, _ := x.typ.Underlying().(*Signature); sig != nil && sig.TypeParams().Len() > 0 {
 		check.errorf(x, WrongTypeArgCount, "cannot use generic function %s without instantiation in %s", x, context)
 		x.mode = invalid
 		return
@@ -261,7 +261,7 @@ func (check *Checker) assignVar(lhs, rhs syntax.Expr, x *operand, context string
 		var target *target
 		// avoid calling ExprString if not needed
 		if T != nil {
-			if _, ok := under(T).(*Signature); ok {
+			if _, ok := T.Underlying().(*Signature); ok {
 				target = newTarget(T, ExprString(lhs))
 			}
 		}
diff --git a/src/cmd/compile/internal/types2/builtins.go b/src/cmd/compile/internal/types2/builtins.go
index df207a2746d627..84acb4ca484164 100644
--- a/src/cmd/compile/internal/types2/builtins.go
+++ b/src/cmd/compile/internal/types2/builtins.go
@@ -144,7 +144,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		// len(x)
 		mode := invalid
 		var val constant.Value
-		switch t := arrayPtrDeref(under(x.typ)).(type) {
+		switch t := arrayPtrDeref(x.typ.Underlying()).(type) {
 		case *Basic:
 			if isString(t) && id == _Len {
 				if x.mode == constant_ {
@@ -203,7 +203,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 
 		if mode == invalid {
 			// avoid error if underlying type is invalid
-			if isValid(under(x.typ)) {
+			if isValid(x.typ.Underlying()) {
 				code := InvalidCap
 				if id == _Len {
 					code = InvalidLen
@@ -322,7 +322,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		// (applyTypeFunc never calls f with a type parameter)
 		f := func(typ Type) Type {
 			assert(!isTypeParam(typ))
-			if t, _ := under(typ).(*Basic); t != nil {
+			if t, _ := typ.Underlying().(*Basic); t != nil {
 				switch t.kind {
 				case Float32:
 					return Typ[Complex64]
@@ -472,7 +472,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		// (applyTypeFunc never calls f with a type parameter)
 		f := func(typ Type) Type {
 			assert(!isTypeParam(typ))
-			if t, _ := under(typ).(*Basic); t != nil {
+			if t, _ := typ.Underlying().(*Basic); t != nil {
 				switch t.kind {
 				case Complex64:
 					return Typ[Float32]
@@ -1020,7 +1020,7 @@ func hasVarSize(t Type, seen map[*Named]bool) (varSized bool) {
 		}()
 	}
 
-	switch u := under(t).(type) {
+	switch u := t.Underlying().(type) {
 	case *Array:
 		return hasVarSize(u.elem, seen)
 	case *Struct:
@@ -1112,7 +1112,7 @@ func makeSig(res Type, args ...Type) *Signature {
 // otherwise it returns typ.
 func arrayPtrDeref(typ Type) Type {
 	if p, ok := Unalias(typ).(*Pointer); ok {
-		if a, _ := under(p.base).(*Array); a != nil {
+		if a, _ := p.base.Underlying().(*Array); a != nil {
 			return a
 		}
 	}
diff --git a/src/cmd/compile/internal/types2/call.go b/src/cmd/compile/internal/types2/call.go
index b7a2ebb41ec976..aca205ad985013 100644
--- a/src/cmd/compile/internal/types2/call.go
+++ b/src/cmd/compile/internal/types2/call.go
@@ -205,7 +205,7 @@ func (check *Checker) callExpr(x *operand, call *syntax.CallExpr) exprKind {
 		case 1:
 			check.expr(nil, x, call.ArgList[0])
 			if x.mode != invalid {
-				if t, _ := under(T).(*Interface); t != nil && !isTypeParam(T) {
+				if t, _ := T.Underlying().(*Interface); t != nil && !isTypeParam(T) {
 					if !t.IsMethodSet() {
 						check.errorf(call, MisplacedConstraintIface, "cannot use interface %s in conversion (contains specific type constraints or is comparable)", T)
 						break
@@ -812,7 +812,7 @@ func (check *Checker) selector(x *operand, e *syntax.SelectorExpr, def *TypeName
 	obj, index, indirect = lookupFieldOrMethod(x.typ, x.mode == variable, check.pkg, sel, false)
 	if obj == nil {
 		// Don't report another error if the underlying type was invalid (go.dev/issue/49541).
-		if !isValid(under(x.typ)) {
+		if !isValid(x.typ.Underlying()) {
 			goto Error
 		}
 
diff --git a/src/cmd/compile/internal/types2/const.go b/src/cmd/compile/internal/types2/const.go
index 5e5bc74ba34ed6..b68d72de4d27f4 100644
--- a/src/cmd/compile/internal/types2/const.go
+++ b/src/cmd/compile/internal/types2/const.go
@@ -33,7 +33,7 @@ func (check *Checker) overflow(x *operand, opPos syntax.Pos) {
 	// x.typ cannot be a type parameter (type
 	// parameters cannot be constant types).
 	if isTyped(x.typ) {
-		check.representable(x, under(x.typ).(*Basic))
+		check.representable(x, x.typ.Underlying().(*Basic))
 		return
 	}
 
diff --git a/src/cmd/compile/internal/types2/conversions.go b/src/cmd/compile/internal/types2/conversions.go
index 0ad79afe71c409..d0920d7ef1006d 100644
--- a/src/cmd/compile/internal/types2/conversions.go
+++ b/src/cmd/compile/internal/types2/conversions.go
@@ -18,7 +18,7 @@ func (check *Checker) conversion(x *operand, T Type) {
 	constArg := x.mode == constant_
 
 	constConvertibleTo := func(T Type, val *constant.Value) bool {
-		switch t, _ := under(T).(*Basic); {
+		switch t, _ := T.Underlying().(*Basic); {
 		case t == nil:
 			// nothing to do
 		case representableConst(x.val, check, t, val):
@@ -142,8 +142,8 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 	origT := T
 	V := Unalias(x.typ)
 	T = Unalias(T)
-	Vu := under(V)
-	Tu := under(T)
+	Vu := V.Underlying()
+	Tu := T.Underlying()
 	Vp, _ := V.(*TypeParam)
 	Tp, _ := T.(*TypeParam)
 
@@ -158,7 +158,7 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 	// and their pointer base types are not type parameters"
 	if V, ok := V.(*Pointer); ok {
 		if T, ok := T.(*Pointer); ok {
-			if IdenticalIgnoreTags(under(V.base), under(T.base)) && !isTypeParam(V.base) && !isTypeParam(T.base) {
+			if IdenticalIgnoreTags(V.base.Underlying(), T.base.Underlying()) && !isTypeParam(V.base) && !isTypeParam(T.base) {
 				return true
 			}
 		}
@@ -211,7 +211,7 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 				return false
 			}
 		case *Pointer:
-			if a, _ := under(a.Elem()).(*Array); a != nil {
+			if a, _ := a.Elem().Underlying().(*Array); a != nil {
 				if Identical(s.Elem(), a.Elem()) {
 					if check == nil || check.allowVersion(go1_17) {
 						return true
@@ -292,23 +292,23 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 }
 
 func isUintptr(typ Type) bool {
-	t, _ := under(typ).(*Basic)
+	t, _ := typ.Underlying().(*Basic)
 	return t != nil && t.kind == Uintptr
 }
 
 func isUnsafePointer(typ Type) bool {
-	t, _ := under(typ).(*Basic)
+	t, _ := typ.Underlying().(*Basic)
 	return t != nil && t.kind == UnsafePointer
 }
 
 func isPointer(typ Type) bool {
-	_, ok := under(typ).(*Pointer)
+	_, ok := typ.Underlying().(*Pointer)
 	return ok
 }
 
 func isBytesOrRunes(typ Type) bool {
-	if s, _ := under(typ).(*Slice); s != nil {
-		t, _ := under(s.elem).(*Basic)
+	if s, _ := typ.Underlying().(*Slice); s != nil {
+		t, _ := s.elem.Underlying().(*Basic)
 		return t != nil && (t.kind == Byte || t.kind == Rune)
 	}
 	return false
diff --git a/src/cmd/compile/internal/types2/decl.go b/src/cmd/compile/internal/types2/decl.go
index 70e79129c91437..b830cb6f4f3c1c 100644
--- a/src/cmd/compile/internal/types2/decl.go
+++ b/src/cmd/compile/internal/types2/decl.go
@@ -391,7 +391,7 @@ func (check *Checker) constDecl(obj *Const, typ, init syntax.Expr, inherited boo
 		if !isConstType(t) {
 			// don't report an error if the type is an invalid C (defined) type
 			// (go.dev/issue/22090)
-			if isValid(under(t)) {
+			if isValid(t.Underlying()) {
 				check.errorf(typ, InvalidConstType, "invalid constant type %s", t)
 			}
 			obj.typ = Typ[Invalid]
diff --git a/src/cmd/compile/internal/types2/expr.go b/src/cmd/compile/internal/types2/expr.go
index e5f9a1c6f7cb49..d62b0247578d6e 100644
--- a/src/cmd/compile/internal/types2/expr.go
+++ b/src/cmd/compile/internal/types2/expr.go
@@ -361,7 +361,7 @@ func (check *Checker) updateExprType(x syntax.Expr, typ Type, final bool) {
 	// If the new type is not final and still untyped, just
 	// update the recorded type.
 	if !final && isUntyped(typ) {
-		old.typ = under(typ).(*Basic)
+		old.typ = typ.Underlying().(*Basic)
 		check.untyped[x] = old
 		return
 	}
@@ -431,7 +431,7 @@ func (check *Checker) implicitTypeAndValue(x *operand, target Type) (Type, const
 		return nil, nil, InvalidUntypedConversion
 	}
 
-	switch u := under(target).(type) {
+	switch u := target.Underlying().(type) {
 	case *Basic:
 		if x.mode == constant_ {
 			v, code := check.representation(x, u)
@@ -616,7 +616,7 @@ Error:
 // incomparableCause returns a more specific cause why typ is not comparable.
 // If there is no more specific cause, the result is "".
 func (check *Checker) incomparableCause(typ Type) string {
-	switch under(typ).(type) {
+	switch typ.Underlying().(type) {
 	case *Slice, *Signature, *Map:
 		return compositeKind(typ) + " can only be compared to nil"
 	}
@@ -963,7 +963,7 @@ type target struct {
 // The result is nil if typ is not a signature.
 func newTarget(typ Type, desc string) *target {
 	if typ != nil {
-		if sig, _ := under(typ).(*Signature); sig != nil {
+		if sig, _ := typ.Underlying().(*Signature); sig != nil {
 			return &target{sig, desc}
 		}
 	}
@@ -1112,7 +1112,7 @@ func (check *Checker) exprInternal(T *target, x *operand, e syntax.Expr, hint Ty
 			check.errorf(x, InvalidAssert, invalidOp+"cannot use type assertion on type parameter value %s", x)
 			goto Error
 		}
-		if _, ok := under(x.typ).(*Interface); !ok {
+		if _, ok := x.typ.Underlying().(*Interface); !ok {
 			check.errorf(x, InvalidAssert, invalidOp+"%s is not an interface", x)
 			goto Error
 		}
diff --git a/src/cmd/compile/internal/types2/gcsizes.go b/src/cmd/compile/internal/types2/gcsizes.go
index 15f3e006425ade..54e8ea23c173c5 100644
--- a/src/cmd/compile/internal/types2/gcsizes.go
+++ b/src/cmd/compile/internal/types2/gcsizes.go
@@ -16,7 +16,7 @@ func (s *gcSizes) Alignof(T Type) (result int64) {
 
 	// For arrays and structs, alignment is defined in terms
 	// of alignment of the elements and fields, respectively.
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Array:
 		// spec: "For a variable x of array type: unsafe.Alignof(x)
 		// is the same as unsafe.Alignof(x[0]), but at least 1."
@@ -96,7 +96,7 @@ func (s *gcSizes) Offsetsof(fields []*Var) []int64 {
 }
 
 func (s *gcSizes) Sizeof(T Type) int64 {
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Basic:
 		assert(isTyped(T))
 		k := t.kind
diff --git a/src/cmd/compile/internal/types2/index.go b/src/cmd/compile/internal/types2/index.go
index 7e16a87332dcdf..ca84184d35afed 100644
--- a/src/cmd/compile/internal/types2/index.go
+++ b/src/cmd/compile/internal/types2/index.go
@@ -35,7 +35,7 @@ func (check *Checker) indexExpr(x *operand, e *syntax.IndexExpr) (isFuncInst boo
 		return false
 
 	case value:
-		if sig, _ := under(x.typ).(*Signature); sig != nil && sig.TypeParams().Len() > 0 {
+		if sig, _ := x.typ.Underlying().(*Signature); sig != nil && sig.TypeParams().Len() > 0 {
 			// function instantiation
 			return true
 		}
@@ -50,7 +50,7 @@ func (check *Checker) indexExpr(x *operand, e *syntax.IndexExpr) (isFuncInst boo
 	// ordinary index expression
 	valid := false
 	length := int64(-1) // valid if >= 0
-	switch typ := under(x.typ).(type) {
+	switch typ := x.typ.Underlying().(type) {
 	case *Basic:
 		if isString(typ) {
 			valid = true
@@ -73,7 +73,7 @@ func (check *Checker) indexExpr(x *operand, e *syntax.IndexExpr) (isFuncInst boo
 		x.typ = typ.elem
 
 	case *Pointer:
-		if typ, _ := under(typ.base).(*Array); typ != nil {
+		if typ, _ := typ.base.Underlying().(*Array); typ != nil {
 			valid = true
 			length = typ.len
 			x.mode = variable
@@ -124,7 +124,7 @@ func (check *Checker) indexExpr(x *operand, e *syntax.IndexExpr) (isFuncInst boo
 					mode = value
 				}
 			case *Pointer:
-				if t, _ := under(t.base).(*Array); t != nil {
+				if t, _ := t.base.Underlying().(*Array); t != nil {
 					l = t.len
 					e = t.elem
 				}
@@ -247,7 +247,7 @@ func (check *Checker) sliceExpr(x *operand, e *syntax.SliceExpr) {
 		// but don't go from untyped string to string.
 		cu = Typ[String]
 		if !isTypeParam(x.typ) {
-			cu = under(x.typ) // untyped string remains untyped
+			cu = x.typ.Underlying() // untyped string remains untyped
 		}
 	}
 
@@ -292,7 +292,7 @@ func (check *Checker) sliceExpr(x *operand, e *syntax.SliceExpr) {
 		x.typ = &Slice{elem: u.elem}
 
 	case *Pointer:
-		if u, _ := under(u.base).(*Array); u != nil {
+		if u, _ := u.base.Underlying().(*Array); u != nil {
 			valid = true
 			length = u.len
 			x.typ = &Slice{elem: u.elem}
diff --git a/src/cmd/compile/internal/types2/infer.go b/src/cmd/compile/internal/types2/infer.go
index 08d422969059f2..e7c59597372413 100644
--- a/src/cmd/compile/internal/types2/infer.go
+++ b/src/cmd/compile/internal/types2/infer.go
@@ -668,7 +668,7 @@ func coreTerm(tpar *TypeParam) (*term, bool) {
 	if n == 1 {
 		if debug {
 			u, _ := commonUnder(tpar, nil)
-			assert(under(single.typ) == u)
+			assert(single.typ.Underlying() == u)
 		}
 		return single, true
 	}
diff --git a/src/cmd/compile/internal/types2/instantiate.go b/src/cmd/compile/internal/types2/instantiate.go
index 8b24f2fc685b81..3c4044ed3c9f2c 100644
--- a/src/cmd/compile/internal/types2/instantiate.go
+++ b/src/cmd/compile/internal/types2/instantiate.go
@@ -226,12 +226,12 @@ func (check *Checker) verify(pos syntax.Pos, tparams []*TypeParam, targs []Type,
 // If the provided cause is non-nil, it may be set to an error string
 // explaining why V does not implement (or satisfy, for constraints) T.
 func (check *Checker) implements(V, T Type, constraint bool, cause *string) bool {
-	Vu := under(V)
-	Tu := under(T)
+	Vu := V.Underlying()
+	Tu := T.Underlying()
 	if !isValid(Vu) || !isValid(Tu) {
 		return true // avoid follow-on errors
 	}
-	if p, _ := Vu.(*Pointer); p != nil && !isValid(under(p.base)) {
+	if p, _ := Vu.(*Pointer); p != nil && !isValid(p.base.Underlying()) {
 		return true // avoid follow-on errors (see go.dev/issue/49541 for an example)
 	}
 
@@ -339,7 +339,7 @@ func (check *Checker) implements(V, T Type, constraint bool, cause *string) bool
 			// If V ∉ t.typ but V ∈ ~t.typ then remember this type
 			// so we can suggest it as an alternative in the error
 			// message.
-			if alt == nil && !t.tilde && Identical(t.typ, under(t.typ)) {
+			if alt == nil && !t.tilde && Identical(t.typ, t.typ.Underlying()) {
 				tt := *t
 				tt.tilde = true
 				if tt.includes(V) {
diff --git a/src/cmd/compile/internal/types2/lookup.go b/src/cmd/compile/internal/types2/lookup.go
index 624b510dc83dc3..0b9282e1a7cfc2 100644
--- a/src/cmd/compile/internal/types2/lookup.go
+++ b/src/cmd/compile/internal/types2/lookup.go
@@ -152,7 +152,7 @@ func lookupFieldOrMethodImpl(T Type, addressable bool, pkg *Package, name string
 
 	// *typ where typ is an interface (incl. a type parameter) has no methods.
 	if isPtr {
-		if _, ok := under(typ).(*Interface); ok {
+		if _, ok := typ.Underlying().(*Interface); ok {
 			return
 		}
 	}
@@ -202,7 +202,7 @@ func lookupFieldOrMethodImpl(T Type, addressable bool, pkg *Package, name string
 				}
 			}
 
-			switch t := under(typ).(type) {
+			switch t := typ.Underlying().(type) {
 			case *Struct:
 				// look for a matching field and collect embedded types
 				for i, f := range t.fields {
@@ -373,7 +373,7 @@ func MissingMethod(V Type, T *Interface, static bool) (method *Func, wrongType b
 // The comparator is used to compare signatures.
 // If a method is missing and cause is not nil, *cause describes the error.
 func (check *Checker) missingMethod(V, T Type, static bool, equivalent func(x, y Type) bool, cause *string) (method *Func, wrongType bool) {
-	methods := under(T).(*Interface).typeSet().methods // T must be an interface
+	methods := T.Underlying().(*Interface).typeSet().methods // T must be an interface
 	if len(methods) == 0 {
 		return nil, false
 	}
@@ -393,7 +393,7 @@ func (check *Checker) missingMethod(V, T Type, static bool, equivalent func(x, y
 	var m *Func // method on T we're trying to implement
 	var f *Func // method on V, if found (state is one of ok, wrongName, wrongSig)
 
-	if u, _ := under(V).(*Interface); u != nil {
+	if u, _ := V.Underlying().(*Interface); u != nil {
 		tset := u.typeSet()
 		for _, m = range methods {
 			_, f = tset.LookupMethod(m.pkg, m.name, false)
@@ -534,7 +534,7 @@ func (check *Checker) hasAllMethods(V, T Type, static bool, equivalent func(x, y
 // hasInvalidEmbeddedFields reports whether T is a struct (or a pointer to a struct) that contains
 // (directly or indirectly) embedded fields with invalid types.
 func hasInvalidEmbeddedFields(T Type, seen map[*Struct]bool) bool {
-	if S, _ := under(derefStructPtr(T)).(*Struct); S != nil && !seen[S] {
+	if S, _ := derefStructPtr(T).Underlying().(*Struct); S != nil && !seen[S] {
 		if seen == nil {
 			seen = make(map[*Struct]bool)
 		}
@@ -549,14 +549,14 @@ func hasInvalidEmbeddedFields(T Type, seen map[*Struct]bool) bool {
 }
 
 func isInterfacePtr(T Type) bool {
-	p, _ := under(T).(*Pointer)
+	p, _ := T.Underlying().(*Pointer)
 	return p != nil && IsInterface(p.base)
 }
 
 // check may be nil.
 func (check *Checker) interfacePtrError(T Type) string {
 	assert(isInterfacePtr(T))
-	if p, _ := under(T).(*Pointer); isTypeParam(p.base) {
+	if p, _ := T.Underlying().(*Pointer); isTypeParam(p.base) {
 		return check.sprintf("type %s is pointer to type parameter, not type parameter", T)
 	}
 	return check.sprintf("type %s is pointer to interface, not interface", T)
@@ -629,8 +629,8 @@ func deref(typ Type) (Type, bool) {
 // derefStructPtr dereferences typ if it is a (named or unnamed) pointer to a
 // (named or unnamed) struct and returns its base. Otherwise it returns typ.
 func derefStructPtr(typ Type) Type {
-	if p, _ := under(typ).(*Pointer); p != nil {
-		if _, ok := under(p.base).(*Struct); ok {
+	if p, _ := typ.Underlying().(*Pointer); p != nil {
+		if _, ok := p.base.Underlying().(*Struct); ok {
 			return p.base
 		}
 	}
diff --git a/src/cmd/compile/internal/types2/object.go b/src/cmd/compile/internal/types2/object.go
index 6331259e1767f5..463ed30308d0ee 100644
--- a/src/cmd/compile/internal/types2/object.go
+++ b/src/cmd/compile/internal/types2/object.go
@@ -639,7 +639,7 @@ func writeObject(buf *bytes.Buffer, obj Object, qf Qualifier) {
 		} else {
 			// TODO(gri) should this be fromRHS for *Named?
 			// (See discussion in #66559.)
-			typ = under(typ)
+			typ = typ.Underlying()
 		}
 	}
 
diff --git a/src/cmd/compile/internal/types2/operand.go b/src/cmd/compile/internal/types2/operand.go
index 81f46af535152b..cd9e9f3575f71a 100644
--- a/src/cmd/compile/internal/types2/operand.go
+++ b/src/cmd/compile/internal/types2/operand.go
@@ -194,7 +194,7 @@ func operandString(x *operand, qf Qualifier) string {
 					what := compositeKind(x.typ)
 					if what == "" {
 						// x.typ must be basic type
-						what = under(x.typ).(*Basic).name
+						what = x.typ.Underlying().(*Basic).name
 					}
 					desc += what + " "
 				}
@@ -229,7 +229,7 @@ func operandString(x *operand, qf Qualifier) string {
 // ("array", "slice", etc.) or the empty string if typ is not
 // composite but a basic type.
 func compositeKind(typ Type) string {
-	switch under(typ).(type) {
+	switch typ.Underlying().(type) {
 	case *Basic:
 		return ""
 	case *Array:
@@ -319,8 +319,8 @@ func (x *operand) assignableTo(check *Checker, T Type, cause *string) (bool, Cod
 		return true, 0
 	}
 
-	Vu := under(V)
-	Tu := under(T)
+	Vu := V.Underlying()
+	Tu := T.Underlying()
 	Vp, _ := V.(*TypeParam)
 	Tp, _ := T.(*TypeParam)
 
diff --git a/src/cmd/compile/internal/types2/predicates.go b/src/cmd/compile/internal/types2/predicates.go
index c157672ba58a4d..60147c5e21138c 100644
--- a/src/cmd/compile/internal/types2/predicates.go
+++ b/src/cmd/compile/internal/types2/predicates.go
@@ -28,11 +28,11 @@ func isString(t Type) bool         { return isBasic(t, IsString) }
 func isIntegerOrFloat(t Type) bool { return isBasic(t, IsInteger|IsFloat) }
 func isConstType(t Type) bool      { return isBasic(t, IsConstType) }
 
-// isBasic reports whether under(t) is a basic type with the specified info.
+// isBasic reports whether t.Underlying() is a basic type with the specified info.
 // If t is a type parameter the result is false; i.e.,
 // isBasic does not look inside a type parameter.
 func isBasic(t Type, info BasicInfo) bool {
-	u, _ := under(t).(*Basic)
+	u, _ := t.Underlying().(*Basic)
 	return u != nil && u.info&info != 0
 }
 
@@ -48,7 +48,7 @@ func allString(t Type) bool          { return allBasic(t, IsString) }
 func allOrdered(t Type) bool         { return allBasic(t, IsOrdered) }
 func allNumericOrString(t Type) bool { return allBasic(t, IsNumeric|IsString) }
 
-// allBasic reports whether under(t) is a basic type with the specified info.
+// allBasic reports whether t.Underlying() is a basic type with the specified info.
 // If t is a type parameter, the result is true if isBasic(t, info) is true
 // for all specific types of the type parameter's type set.
 func allBasic(t Type, info BasicInfo) bool {
@@ -107,7 +107,7 @@ func isUntypedNumeric(t Type) bool {
 
 // IsInterface reports whether t is an interface type.
 func IsInterface(t Type) bool {
-	_, ok := under(t).(*Interface)
+	_, ok := t.Underlying().(*Interface)
 	return ok
 }
 
@@ -163,7 +163,7 @@ func comparableType(T Type, dynamic bool, seen map[Type]bool) *typeError {
 	}
 	seen[T] = true
 
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Basic:
 		// assume invalid types to be comparable to avoid follow-up errors
 		if t.kind == UntypedNil {
@@ -206,7 +206,7 @@ func comparableType(T Type, dynamic bool, seen map[Type]bool) *typeError {
 
 // hasNil reports whether type t includes the nil value.
 func hasNil(t Type) bool {
-	switch u := under(t).(type) {
+	switch u := t.Underlying().(type) {
 	case *Basic:
 		return u.kind == UnsafePointer
 	case *Slice, *Pointer, *Signature, *Map, *Chan:
diff --git a/src/cmd/compile/internal/types2/range.go b/src/cmd/compile/internal/types2/range.go
index b654601eafc73e..899f5c09911a5e 100644
--- a/src/cmd/compile/internal/types2/range.go
+++ b/src/cmd/compile/internal/types2/range.go
@@ -35,7 +35,7 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *syntax.ForStmt, no
 	check.expr(nil, &x, rangeVar)
 
 	if isTypes2 && x.mode != invalid && sValue == nil && !check.hasCallOrRecv {
-		if t, ok := arrayPtrDeref(under(x.typ)).(*Array); ok {
+		if t, ok := arrayPtrDeref(x.typ.Underlying()).(*Array); ok {
 			for {
 				// Put constant info on the thing inside parentheses.
 				// That's where (*../noder/writer).expr expects it.
diff --git a/src/cmd/compile/internal/types2/sizes.go b/src/cmd/compile/internal/types2/sizes.go
index 7b1c00b40ab9a9..534ecfba35ced7 100644
--- a/src/cmd/compile/internal/types2/sizes.go
+++ b/src/cmd/compile/internal/types2/sizes.go
@@ -54,7 +54,7 @@ func (s *StdSizes) Alignof(T Type) (result int64) {
 
 	// For arrays and structs, alignment is defined in terms
 	// of alignment of the elements and fields, respectively.
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Array:
 		// spec: "For a variable x of array type: unsafe.Alignof(x)
 		// is the same as unsafe.Alignof(x[0]), but at least 1."
@@ -162,7 +162,7 @@ var basicSizes = [...]byte{
 }
 
 func (s *StdSizes) Sizeof(T Type) int64 {
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Basic:
 		assert(isTyped(T))
 		k := t.kind
@@ -307,7 +307,7 @@ func (conf *Config) offsetsof(T *Struct) []int64 {
 func (conf *Config) offsetof(T Type, index []int) int64 {
 	var offs int64
 	for _, i := range index {
-		s := under(T).(*Struct)
+		s := T.Underlying().(*Struct)
 		d := conf.offsetsof(s)[i]
 		if d < 0 {
 			return -1
diff --git a/src/cmd/compile/internal/types2/struct.go b/src/cmd/compile/internal/types2/struct.go
index f5cdc472f77de2..99b75332e8ffec 100644
--- a/src/cmd/compile/internal/types2/struct.go
+++ b/src/cmd/compile/internal/types2/struct.go
@@ -141,12 +141,12 @@ func (check *Checker) structType(styp *Struct, e *syntax.StructType) {
 			// Because we have a name, typ must be of the form T or *T, where T is the name
 			// of a (named or alias) type, and t (= deref(typ)) must be the type of T.
 			// We must delay this check to the end because we don't want to instantiate
-			// (via under(t)) a possibly incomplete type.
+			// (via t.Underlying()) a possibly incomplete type.
 			embeddedTyp := typ // for closure below
 			embeddedPos := pos
 			check.later(func() {
 				t, isPtr := deref(embeddedTyp)
-				switch u := under(t).(type) {
+				switch u := t.Underlying().(type) {
 				case *Basic:
 					if !isValid(t) {
 						// error was reported before
diff --git a/src/cmd/compile/internal/types2/typeparam.go b/src/cmd/compile/internal/types2/typeparam.go
index c60b5eb41722e4..2ffa00c32c7ec4 100644
--- a/src/cmd/compile/internal/types2/typeparam.go
+++ b/src/cmd/compile/internal/types2/typeparam.go
@@ -113,7 +113,7 @@ func (t *TypeParam) iface() *Interface {
 
 	// determine constraint interface
 	var ityp *Interface
-	switch u := under(bound).(type) {
+	switch u := bound.Underlying().(type) {
 	case *Basic:
 		if !isValid(u) {
 			// error is reported elsewhere
diff --git a/src/cmd/compile/internal/types2/typeset.go b/src/cmd/compile/internal/types2/typeset.go
index ce487e74f7232a..fafe6f368ba432 100644
--- a/src/cmd/compile/internal/types2/typeset.go
+++ b/src/cmd/compile/internal/types2/typeset.go
@@ -114,13 +114,13 @@ func (s *_TypeSet) all(f func(t, u Type) bool) bool {
 
 	for _, t := range s.terms {
 		assert(t.typ != nil)
-		// Unalias(x) == under(x) for ~x terms
+		// Unalias(x) == x.Underlying() for ~x terms
 		u := Unalias(t.typ)
 		if !t.tilde {
-			u = under(u)
+			u = u.Underlying()
 		}
 		if debug {
-			assert(Identical(u, under(u)))
+			assert(Identical(u, u.Underlying()))
 		}
 		if !f(t.typ, u) {
 			return false
@@ -264,7 +264,7 @@ func computeInterfaceTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *_
 		}
 		var comparable bool
 		var terms termlist
-		switch u := under(typ).(type) {
+		switch u := typ.Underlying().(type) {
 		case *Interface:
 			// For now we don't permit type parameters as constraints.
 			assert(!isTypeParam(typ))
@@ -380,7 +380,7 @@ func computeUnionTypeSet(check *Checker, unionSets map[*Union]*_TypeSet, pos syn
 	var allTerms termlist
 	for _, t := range utyp.terms {
 		var terms termlist
-		u := under(t.typ)
+		u := t.typ.Underlying()
 		if ui, _ := u.(*Interface); ui != nil {
 			// For now we don't permit type parameters as constraints.
 			assert(!isTypeParam(t.typ))
diff --git a/src/cmd/compile/internal/types2/typeset_test.go b/src/cmd/compile/internal/types2/typeset_test.go
index 40ca28e525feb5..bcff2489306828 100644
--- a/src/cmd/compile/internal/types2/typeset_test.go
+++ b/src/cmd/compile/internal/types2/typeset_test.go
@@ -64,7 +64,7 @@ func TestTypeSetString(t *testing.T) {
 		if obj == nil {
 			t.Fatalf("%s: T not found (invalid test case)", body)
 		}
-		T, ok := under(obj.Type()).(*Interface)
+		T, ok := obj.Type().Underlying().(*Interface)
 		if !ok {
 			t.Fatalf("%s: %v is not an interface (invalid test case)", body, obj)
 		}
diff --git a/src/cmd/compile/internal/types2/typestring.go b/src/cmd/compile/internal/types2/typestring.go
index 47f53bc12d77b5..b1f0d0929bae33 100644
--- a/src/cmd/compile/internal/types2/typestring.go
+++ b/src/cmd/compile/internal/types2/typestring.go
@@ -455,7 +455,7 @@ func (w *typeWriter) tuple(tup *Tuple, variadic bool) {
 				} else {
 					// special case:
 					// append(s, "foo"...) leads to signature func([]byte, string...)
-					if t, _ := under(typ).(*Basic); t == nil || t.kind != String {
+					if t, _ := typ.Underlying().(*Basic); t == nil || t.kind != String {
 						w.error("expected string type")
 						continue
 					}
diff --git a/src/cmd/compile/internal/types2/typeterm.go b/src/cmd/compile/internal/types2/typeterm.go
index 97791324e1e75c..cb11811d458c5a 100644
--- a/src/cmd/compile/internal/types2/typeterm.go
+++ b/src/cmd/compile/internal/types2/typeterm.go
@@ -115,7 +115,7 @@ func (x *term) includes(t Type) bool {
 
 	u := t
 	if x.tilde {
-		u = under(u)
+		u = u.Underlying()
 	}
 	return Identical(x.typ, u)
 }
@@ -155,11 +155,11 @@ func (x *term) disjoint(y *term) bool {
 	}
 	ux := x.typ
 	if y.tilde {
-		ux = under(ux)
+		ux = ux.Underlying()
 	}
 	uy := y.typ
 	if x.tilde {
-		uy = under(uy)
+		uy = uy.Underlying()
 	}
 	return !Identical(ux, uy)
 }
diff --git a/src/cmd/compile/internal/types2/typexpr.go b/src/cmd/compile/internal/types2/typexpr.go
index b1533de5048ae1..8601ce627768e4 100644
--- a/src/cmd/compile/internal/types2/typexpr.go
+++ b/src/cmd/compile/internal/types2/typexpr.go
@@ -169,11 +169,11 @@ func (check *Checker) validVarType(e syntax.Expr, typ Type) {
 		return
 	}
 
-	// We don't want to call under() or complete interfaces while we are in
+	// We don't want to call typ.Underlying() or complete interfaces while we are in
 	// the middle of type-checking parameter declarations that might belong
 	// to interface methods. Delay this check to the end of type-checking.
 	check.later(func() {
-		if t, _ := under(typ).(*Interface); t != nil {
+		if t, _ := typ.Underlying().(*Interface); t != nil {
 			pos := syntax.StartPos(e)
 			tset := computeInterfaceTypeSet(check, pos, t) // TODO(gri) is this the correct position?
 			if !tset.IsMethodSet() {
@@ -239,7 +239,7 @@ func (check *Checker) typInternal(e0 syntax.Expr, def *TypeName) (T Type) {
 			check.indent--
 			var under Type
 			if T != nil {
-				// Calling under() here may lead to endless instantiations.
+				// Calling T.Underlying() here may lead to endless instantiations.
 				// Test case: type T[P any] *T[P]
 				under = safeUnderlying(T)
 			}
diff --git a/src/cmd/compile/internal/types2/under.go b/src/cmd/compile/internal/types2/under.go
index 8e9871eacd0d90..98c62733c7cd99 100644
--- a/src/cmd/compile/internal/types2/under.go
+++ b/src/cmd/compile/internal/types2/under.go
@@ -6,17 +6,8 @@ package types2
 
 import "iter"
 
-// under returns the true expanded underlying type.
-// If it doesn't exist, the result is Typ[Invalid].
-// under must only be called when a type is known
-// to be fully set up.
-func under(t Type) Type {
-	// TODO(markfreeman): Remove this function, it just delegates.
-	return t.Underlying()
-}
-
 // If typ is a type parameter, underIs returns the result of typ.underIs(f).
-// Otherwise, underIs returns the result of f(under(typ)).
+// Otherwise, underIs returns the result of f(typ.Underlying()).
 func underIs(typ Type, f func(Type) bool) bool {
 	return all(typ, func(_, u Type) bool {
 		return f(u)
@@ -29,7 +20,7 @@ func all(t Type, f func(t, u Type) bool) bool {
 	if p, _ := Unalias(t).(*TypeParam); p != nil {
 		return p.typeset(f)
 	}
-	return f(t, under(t))
+	return f(t, t.Underlying())
 }
 
 // typeset is an iterator over the (type/underlying type) pairs of the
diff --git a/src/cmd/compile/internal/types2/unify.go b/src/cmd/compile/internal/types2/unify.go
index 8e112248c635ab..eecef455ac577c 100644
--- a/src/cmd/compile/internal/types2/unify.go
+++ b/src/cmd/compile/internal/types2/unify.go
@@ -270,7 +270,7 @@ func (u *unifier) inferred(tparams []*TypeParam) []Type {
 // it is a non-type parameter interface. Otherwise it returns nil.
 func asInterface(x Type) (i *Interface) {
 	if _, ok := Unalias(x).(*TypeParam); !ok {
-		i, _ = under(x).(*Interface)
+		i, _ = x.Underlying().(*Interface)
 	}
 	return i
 }
@@ -430,7 +430,7 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
 						u.set(px, y)
 					default:
 						// Neither x nor y are defined types.
-						if yc, _ := under(y).(*Chan); yc != nil && yc.dir != SendRecv {
+						if yc, _ := y.Underlying().(*Chan); yc != nil && yc.dir != SendRecv {
 							// y is a directed channel type: select y.
 							u.set(px, y)
 						}
diff --git a/src/cmd/compile/internal/types2/union.go b/src/cmd/compile/internal/types2/union.go
index 1bf4353f264e34..ab0bd43cd350ac 100644
--- a/src/cmd/compile/internal/types2/union.go
+++ b/src/cmd/compile/internal/types2/union.go
@@ -93,7 +93,7 @@ func parseUnion(check *Checker, uexpr syntax.Expr) Type {
 				continue
 			}
 
-			u := under(t.typ)
+			u := t.typ.Underlying()
 			f, _ := u.(*Interface)
 			if t.tilde {
 				if f != nil {
diff --git a/src/go/types/assignments.go b/src/go/types/assignments.go
index 3b40a9f84830e6..1524451af766ff 100644
--- a/src/go/types/assignments.go
+++ b/src/go/types/assignments.go
@@ -94,7 +94,7 @@ func (check *Checker) assignment(x *operand, T Type, context string) {
 	// x.typ is typed
 
 	// A generic (non-instantiated) function value cannot be assigned to a variable.
-	if sig, _ := under(x.typ).(*Signature); sig != nil && sig.TypeParams().Len() > 0 {
+	if sig, _ := x.typ.Underlying().(*Signature); sig != nil && sig.TypeParams().Len() > 0 {
 		check.errorf(x, WrongTypeArgCount, "cannot use generic function %s without instantiation in %s", x, context)
 		x.mode = invalid
 		return
@@ -264,7 +264,7 @@ func (check *Checker) assignVar(lhs, rhs ast.Expr, x *operand, context string) {
 		var target *target
 		// avoid calling ExprString if not needed
 		if T != nil {
-			if _, ok := under(T).(*Signature); ok {
+			if _, ok := T.Underlying().(*Signature); ok {
 				target = newTarget(T, ExprString(lhs))
 			}
 		}
diff --git a/src/go/types/builtins.go b/src/go/types/builtins.go
index 9b03a40cbc3440..f59c9ddd120360 100644
--- a/src/go/types/builtins.go
+++ b/src/go/types/builtins.go
@@ -147,7 +147,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		// len(x)
 		mode := invalid
 		var val constant.Value
-		switch t := arrayPtrDeref(under(x.typ)).(type) {
+		switch t := arrayPtrDeref(x.typ.Underlying()).(type) {
 		case *Basic:
 			if isString(t) && id == _Len {
 				if x.mode == constant_ {
@@ -206,7 +206,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 
 		if mode == invalid {
 			// avoid error if underlying type is invalid
-			if isValid(under(x.typ)) {
+			if isValid(x.typ.Underlying()) {
 				code := InvalidCap
 				if id == _Len {
 					code = InvalidLen
@@ -325,7 +325,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		// (applyTypeFunc never calls f with a type parameter)
 		f := func(typ Type) Type {
 			assert(!isTypeParam(typ))
-			if t, _ := under(typ).(*Basic); t != nil {
+			if t, _ := typ.Underlying().(*Basic); t != nil {
 				switch t.kind {
 				case Float32:
 					return Typ[Complex64]
@@ -475,7 +475,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
 		// (applyTypeFunc never calls f with a type parameter)
 		f := func(typ Type) Type {
 			assert(!isTypeParam(typ))
-			if t, _ := under(typ).(*Basic); t != nil {
+			if t, _ := typ.Underlying().(*Basic); t != nil {
 				switch t.kind {
 				case Complex64:
 					return Typ[Float32]
@@ -1023,7 +1023,7 @@ func hasVarSize(t Type, seen map[*Named]bool) (varSized bool) {
 		}()
 	}
 
-	switch u := under(t).(type) {
+	switch u := t.Underlying().(type) {
 	case *Array:
 		return hasVarSize(u.elem, seen)
 	case *Struct:
@@ -1115,7 +1115,7 @@ func makeSig(res Type, args ...Type) *Signature {
 // otherwise it returns typ.
 func arrayPtrDeref(typ Type) Type {
 	if p, ok := Unalias(typ).(*Pointer); ok {
-		if a, _ := under(p.base).(*Array); a != nil {
+		if a, _ := p.base.Underlying().(*Array); a != nil {
 			return a
 		}
 	}
diff --git a/src/go/types/call.go b/src/go/types/call.go
index 33fe8bb9bfa84f..44549b8727cf0b 100644
--- a/src/go/types/call.go
+++ b/src/go/types/call.go
@@ -211,7 +211,7 @@ func (check *Checker) callExpr(x *operand, call *ast.CallExpr) exprKind {
 					check.errorf(call.Args[0], BadDotDotDotSyntax, "invalid use of ... in conversion to %s", T)
 					break
 				}
-				if t, _ := under(T).(*Interface); t != nil && !isTypeParam(T) {
+				if t, _ := T.Underlying().(*Interface); t != nil && !isTypeParam(T) {
 					if !t.IsMethodSet() {
 						check.errorf(call, MisplacedConstraintIface, "cannot use interface %s in conversion (contains specific type constraints or is comparable)", T)
 						break
@@ -815,7 +815,7 @@ func (check *Checker) selector(x *operand, e *ast.SelectorExpr, def *TypeName, w
 	obj, index, indirect = lookupFieldOrMethod(x.typ, x.mode == variable, check.pkg, sel, false)
 	if obj == nil {
 		// Don't report another error if the underlying type was invalid (go.dev/issue/49541).
-		if !isValid(under(x.typ)) {
+		if !isValid(x.typ.Underlying()) {
 			goto Error
 		}
 
diff --git a/src/go/types/const.go b/src/go/types/const.go
index c1ed14abe2c12d..dc9efa0130eae3 100644
--- a/src/go/types/const.go
+++ b/src/go/types/const.go
@@ -35,7 +35,7 @@ func (check *Checker) overflow(x *operand, opPos token.Pos) {
 	// x.typ cannot be a type parameter (type
 	// parameters cannot be constant types).
 	if isTyped(x.typ) {
-		check.representable(x, under(x.typ).(*Basic))
+		check.representable(x, x.typ.Underlying().(*Basic))
 		return
 	}
 
diff --git a/src/go/types/conversions.go b/src/go/types/conversions.go
index 6a9f263c57c377..daef80adf8058b 100644
--- a/src/go/types/conversions.go
+++ b/src/go/types/conversions.go
@@ -21,7 +21,7 @@ func (check *Checker) conversion(x *operand, T Type) {
 	constArg := x.mode == constant_
 
 	constConvertibleTo := func(T Type, val *constant.Value) bool {
-		switch t, _ := under(T).(*Basic); {
+		switch t, _ := T.Underlying().(*Basic); {
 		case t == nil:
 			// nothing to do
 		case representableConst(x.val, check, t, val):
@@ -145,8 +145,8 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 	origT := T
 	V := Unalias(x.typ)
 	T = Unalias(T)
-	Vu := under(V)
-	Tu := under(T)
+	Vu := V.Underlying()
+	Tu := T.Underlying()
 	Vp, _ := V.(*TypeParam)
 	Tp, _ := T.(*TypeParam)
 
@@ -161,7 +161,7 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 	// and their pointer base types are not type parameters"
 	if V, ok := V.(*Pointer); ok {
 		if T, ok := T.(*Pointer); ok {
-			if IdenticalIgnoreTags(under(V.base), under(T.base)) && !isTypeParam(V.base) && !isTypeParam(T.base) {
+			if IdenticalIgnoreTags(V.base.Underlying(), T.base.Underlying()) && !isTypeParam(V.base) && !isTypeParam(T.base) {
 				return true
 			}
 		}
@@ -214,7 +214,7 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 				return false
 			}
 		case *Pointer:
-			if a, _ := under(a.Elem()).(*Array); a != nil {
+			if a, _ := a.Elem().Underlying().(*Array); a != nil {
 				if Identical(s.Elem(), a.Elem()) {
 					if check == nil || check.allowVersion(go1_17) {
 						return true
@@ -295,23 +295,23 @@ func (x *operand) convertibleTo(check *Checker, T Type, cause *string) bool {
 }
 
 func isUintptr(typ Type) bool {
-	t, _ := under(typ).(*Basic)
+	t, _ := typ.Underlying().(*Basic)
 	return t != nil && t.kind == Uintptr
 }
 
 func isUnsafePointer(typ Type) bool {
-	t, _ := under(typ).(*Basic)
+	t, _ := typ.Underlying().(*Basic)
 	return t != nil && t.kind == UnsafePointer
 }
 
 func isPointer(typ Type) bool {
-	_, ok := under(typ).(*Pointer)
+	_, ok := typ.Underlying().(*Pointer)
 	return ok
 }
 
 func isBytesOrRunes(typ Type) bool {
-	if s, _ := under(typ).(*Slice); s != nil {
-		t, _ := under(s.elem).(*Basic)
+	if s, _ := typ.Underlying().(*Slice); s != nil {
+		t, _ := s.elem.Underlying().(*Basic)
 		return t != nil && (t.kind == Byte || t.kind == Rune)
 	}
 	return false
diff --git a/src/go/types/decl.go b/src/go/types/decl.go
index 6e61dd9a131429..15726dc4e2427d 100644
--- a/src/go/types/decl.go
+++ b/src/go/types/decl.go
@@ -466,7 +466,7 @@ func (check *Checker) constDecl(obj *Const, typ, init ast.Expr, inherited bool)
 		if !isConstType(t) {
 			// don't report an error if the type is an invalid C (defined) type
 			// (go.dev/issue/22090)
-			if isValid(under(t)) {
+			if isValid(t.Underlying()) {
 				check.errorf(typ, InvalidConstType, "invalid constant type %s", t)
 			}
 			obj.typ = Typ[Invalid]
diff --git a/src/go/types/expr.go b/src/go/types/expr.go
index 97d8c42997863c..65995d9bffe690 100644
--- a/src/go/types/expr.go
+++ b/src/go/types/expr.go
@@ -336,7 +336,7 @@ func (check *Checker) updateExprType(x ast.Expr, typ Type, final bool) {
 	// If the new type is not final and still untyped, just
 	// update the recorded type.
 	if !final && isUntyped(typ) {
-		old.typ = under(typ).(*Basic)
+		old.typ = typ.Underlying().(*Basic)
 		check.untyped[x] = old
 		return
 	}
@@ -398,7 +398,7 @@ func (check *Checker) implicitTypeAndValue(x *operand, target Type) (Type, const
 		return nil, nil, InvalidUntypedConversion
 	}
 
-	switch u := under(target).(type) {
+	switch u := target.Underlying().(type) {
 	case *Basic:
 		if x.mode == constant_ {
 			v, code := check.representation(x, u)
@@ -605,7 +605,7 @@ Error:
 // incomparableCause returns a more specific cause why typ is not comparable.
 // If there is no more specific cause, the result is "".
 func (check *Checker) incomparableCause(typ Type) string {
-	switch under(typ).(type) {
+	switch typ.Underlying().(type) {
 	case *Slice, *Signature, *Map:
 		return compositeKind(typ) + " can only be compared to nil"
 	}
@@ -955,7 +955,7 @@ type target struct {
 // The result is nil if typ is not a signature.
 func newTarget(typ Type, desc string) *target {
 	if typ != nil {
-		if sig, _ := under(typ).(*Signature); sig != nil {
+		if sig, _ := typ.Underlying().(*Signature); sig != nil {
 			return &target{sig, desc}
 		}
 	}
@@ -1101,7 +1101,7 @@ func (check *Checker) exprInternal(T *target, x *operand, e ast.Expr, hint Type)
 			check.errorf(x, InvalidAssert, invalidOp+"cannot use type assertion on type parameter value %s", x)
 			goto Error
 		}
-		if _, ok := under(x.typ).(*Interface); !ok {
+		if _, ok := x.typ.Underlying().(*Interface); !ok {
 			check.errorf(x, InvalidAssert, invalidOp+"%s is not an interface", x)
 			goto Error
 		}
diff --git a/src/go/types/gcsizes.go b/src/go/types/gcsizes.go
index 227c53e1d280a7..adc350a6c2d001 100644
--- a/src/go/types/gcsizes.go
+++ b/src/go/types/gcsizes.go
@@ -19,7 +19,7 @@ func (s *gcSizes) Alignof(T Type) (result int64) {
 
 	// For arrays and structs, alignment is defined in terms
 	// of alignment of the elements and fields, respectively.
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Array:
 		// spec: "For a variable x of array type: unsafe.Alignof(x)
 		// is the same as unsafe.Alignof(x[0]), but at least 1."
@@ -99,7 +99,7 @@ func (s *gcSizes) Offsetsof(fields []*Var) []int64 {
 }
 
 func (s *gcSizes) Sizeof(T Type) int64 {
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Basic:
 		assert(isTyped(T))
 		k := t.kind
diff --git a/src/go/types/index.go b/src/go/types/index.go
index 1d4f36dcf3c577..42e472001318cb 100644
--- a/src/go/types/index.go
+++ b/src/go/types/index.go
@@ -36,7 +36,7 @@ func (check *Checker) indexExpr(x *operand, e *indexedExpr) (isFuncInst bool) {
 		return false
 
 	case value:
-		if sig, _ := under(x.typ).(*Signature); sig != nil && sig.TypeParams().Len() > 0 {
+		if sig, _ := x.typ.Underlying().(*Signature); sig != nil && sig.TypeParams().Len() > 0 {
 			// function instantiation
 			return true
 		}
@@ -51,7 +51,7 @@ func (check *Checker) indexExpr(x *operand, e *indexedExpr) (isFuncInst bool) {
 	// ordinary index expression
 	valid := false
 	length := int64(-1) // valid if >= 0
-	switch typ := under(x.typ).(type) {
+	switch typ := x.typ.Underlying().(type) {
 	case *Basic:
 		if isString(typ) {
 			valid = true
@@ -74,7 +74,7 @@ func (check *Checker) indexExpr(x *operand, e *indexedExpr) (isFuncInst bool) {
 		x.typ = typ.elem
 
 	case *Pointer:
-		if typ, _ := under(typ.base).(*Array); typ != nil {
+		if typ, _ := typ.base.Underlying().(*Array); typ != nil {
 			valid = true
 			length = typ.len
 			x.mode = variable
@@ -125,7 +125,7 @@ func (check *Checker) indexExpr(x *operand, e *indexedExpr) (isFuncInst bool) {
 					mode = value
 				}
 			case *Pointer:
-				if t, _ := under(t.base).(*Array); t != nil {
+				if t, _ := t.base.Underlying().(*Array); t != nil {
 					l = t.len
 					e = t.elem
 				}
@@ -252,7 +252,7 @@ func (check *Checker) sliceExpr(x *operand, e *ast.SliceExpr) {
 		// but don't go from untyped string to string.
 		cu = Typ[String]
 		if !isTypeParam(x.typ) {
-			cu = under(x.typ) // untyped string remains untyped
+			cu = x.typ.Underlying() // untyped string remains untyped
 		}
 	}
 
@@ -297,7 +297,7 @@ func (check *Checker) sliceExpr(x *operand, e *ast.SliceExpr) {
 		x.typ = &Slice{elem: u.elem}
 
 	case *Pointer:
-		if u, _ := under(u.base).(*Array); u != nil {
+		if u, _ := u.base.Underlying().(*Array); u != nil {
 			valid = true
 			length = u.len
 			x.typ = &Slice{elem: u.elem}
diff --git a/src/go/types/infer.go b/src/go/types/infer.go
index e955880674c136..a8da7ac674abf9 100644
--- a/src/go/types/infer.go
+++ b/src/go/types/infer.go
@@ -671,7 +671,7 @@ func coreTerm(tpar *TypeParam) (*term, bool) {
 	if n == 1 {
 		if debug {
 			u, _ := commonUnder(tpar, nil)
-			assert(under(single.typ) == u)
+			assert(single.typ.Underlying() == u)
 		}
 		return single, true
 	}
diff --git a/src/go/types/instantiate.go b/src/go/types/instantiate.go
index 0bccd3dff6b02c..6488494cd83227 100644
--- a/src/go/types/instantiate.go
+++ b/src/go/types/instantiate.go
@@ -229,12 +229,12 @@ func (check *Checker) verify(pos token.Pos, tparams []*TypeParam, targs []Type,
 // If the provided cause is non-nil, it may be set to an error string
 // explaining why V does not implement (or satisfy, for constraints) T.
 func (check *Checker) implements(V, T Type, constraint bool, cause *string) bool {
-	Vu := under(V)
-	Tu := under(T)
+	Vu := V.Underlying()
+	Tu := T.Underlying()
 	if !isValid(Vu) || !isValid(Tu) {
 		return true // avoid follow-on errors
 	}
-	if p, _ := Vu.(*Pointer); p != nil && !isValid(under(p.base)) {
+	if p, _ := Vu.(*Pointer); p != nil && !isValid(p.base.Underlying()) {
 		return true // avoid follow-on errors (see go.dev/issue/49541 for an example)
 	}
 
@@ -342,7 +342,7 @@ func (check *Checker) implements(V, T Type, constraint bool, cause *string) bool
 			// If V ∉ t.typ but V ∈ ~t.typ then remember this type
 			// so we can suggest it as an alternative in the error
 			// message.
-			if alt == nil && !t.tilde && Identical(t.typ, under(t.typ)) {
+			if alt == nil && !t.tilde && Identical(t.typ, t.typ.Underlying()) {
 				tt := *t
 				tt.tilde = true
 				if tt.includes(V) {
diff --git a/src/go/types/lookup.go b/src/go/types/lookup.go
index 16d63ae0f118ce..c479303a350b8c 100644
--- a/src/go/types/lookup.go
+++ b/src/go/types/lookup.go
@@ -155,7 +155,7 @@ func lookupFieldOrMethodImpl(T Type, addressable bool, pkg *Package, name string
 
 	// *typ where typ is an interface (incl. a type parameter) has no methods.
 	if isPtr {
-		if _, ok := under(typ).(*Interface); ok {
+		if _, ok := typ.Underlying().(*Interface); ok {
 			return
 		}
 	}
@@ -205,7 +205,7 @@ func lookupFieldOrMethodImpl(T Type, addressable bool, pkg *Package, name string
 				}
 			}
 
-			switch t := under(typ).(type) {
+			switch t := typ.Underlying().(type) {
 			case *Struct:
 				// look for a matching field and collect embedded types
 				for i, f := range t.fields {
@@ -376,7 +376,7 @@ func MissingMethod(V Type, T *Interface, static bool) (method *Func, wrongType b
 // The comparator is used to compare signatures.
 // If a method is missing and cause is not nil, *cause describes the error.
 func (check *Checker) missingMethod(V, T Type, static bool, equivalent func(x, y Type) bool, cause *string) (method *Func, wrongType bool) {
-	methods := under(T).(*Interface).typeSet().methods // T must be an interface
+	methods := T.Underlying().(*Interface).typeSet().methods // T must be an interface
 	if len(methods) == 0 {
 		return nil, false
 	}
@@ -396,7 +396,7 @@ func (check *Checker) missingMethod(V, T Type, static bool, equivalent func(x, y
 	var m *Func // method on T we're trying to implement
 	var f *Func // method on V, if found (state is one of ok, wrongName, wrongSig)
 
-	if u, _ := under(V).(*Interface); u != nil {
+	if u, _ := V.Underlying().(*Interface); u != nil {
 		tset := u.typeSet()
 		for _, m = range methods {
 			_, f = tset.LookupMethod(m.pkg, m.name, false)
@@ -537,7 +537,7 @@ func (check *Checker) hasAllMethods(V, T Type, static bool, equivalent func(x, y
 // hasInvalidEmbeddedFields reports whether T is a struct (or a pointer to a struct) that contains
 // (directly or indirectly) embedded fields with invalid types.
 func hasInvalidEmbeddedFields(T Type, seen map[*Struct]bool) bool {
-	if S, _ := under(derefStructPtr(T)).(*Struct); S != nil && !seen[S] {
+	if S, _ := derefStructPtr(T).Underlying().(*Struct); S != nil && !seen[S] {
 		if seen == nil {
 			seen = make(map[*Struct]bool)
 		}
@@ -552,14 +552,14 @@ func hasInvalidEmbeddedFields(T Type, seen map[*Struct]bool) bool {
 }
 
 func isInterfacePtr(T Type) bool {
-	p, _ := under(T).(*Pointer)
+	p, _ := T.Underlying().(*Pointer)
 	return p != nil && IsInterface(p.base)
 }
 
 // check may be nil.
 func (check *Checker) interfacePtrError(T Type) string {
 	assert(isInterfacePtr(T))
-	if p, _ := under(T).(*Pointer); isTypeParam(p.base) {
+	if p, _ := T.Underlying().(*Pointer); isTypeParam(p.base) {
 		return check.sprintf("type %s is pointer to type parameter, not type parameter", T)
 	}
 	return check.sprintf("type %s is pointer to interface, not interface", T)
@@ -632,8 +632,8 @@ func deref(typ Type) (Type, bool) {
 // derefStructPtr dereferences typ if it is a (named or unnamed) pointer to a
 // (named or unnamed) struct and returns its base. Otherwise it returns typ.
 func derefStructPtr(typ Type) Type {
-	if p, _ := under(typ).(*Pointer); p != nil {
-		if _, ok := under(p.base).(*Struct); ok {
+	if p, _ := typ.Underlying().(*Pointer); p != nil {
+		if _, ok := p.base.Underlying().(*Struct); ok {
 			return p.base
 		}
 	}
diff --git a/src/go/types/methodset.go b/src/go/types/methodset.go
index ac8f0bdd288e27..2eac62e6028e0f 100644
--- a/src/go/types/methodset.go
+++ b/src/go/types/methodset.go
@@ -133,7 +133,7 @@ func NewMethodSet(T Type) *MethodSet {
 				}
 			}
 
-			switch t := under(typ).(type) {
+			switch t := typ.Underlying().(type) {
 			case *Struct:
 				for i, f := range t.fields {
 					if fset == nil {
diff --git a/src/go/types/object.go b/src/go/types/object.go
index 305471222c5ccc..1bba5d52a8b2b6 100644
--- a/src/go/types/object.go
+++ b/src/go/types/object.go
@@ -642,7 +642,7 @@ func writeObject(buf *bytes.Buffer, obj Object, qf Qualifier) {
 		} else {
 			// TODO(gri) should this be fromRHS for *Named?
 			// (See discussion in #66559.)
-			typ = under(typ)
+			typ = typ.Underlying()
 		}
 	}
 
diff --git a/src/go/types/operand.go b/src/go/types/operand.go
index d933c173ff60ee..9abeaafae0c4d2 100644
--- a/src/go/types/operand.go
+++ b/src/go/types/operand.go
@@ -198,7 +198,7 @@ func operandString(x *operand, qf Qualifier) string {
 					what := compositeKind(x.typ)
 					if what == "" {
 						// x.typ must be basic type
-						what = under(x.typ).(*Basic).name
+						what = x.typ.Underlying().(*Basic).name
 					}
 					desc += what + " "
 				}
@@ -233,7 +233,7 @@ func operandString(x *operand, qf Qualifier) string {
 // ("array", "slice", etc.) or the empty string if typ is not
 // composite but a basic type.
 func compositeKind(typ Type) string {
-	switch under(typ).(type) {
+	switch typ.Underlying().(type) {
 	case *Basic:
 		return ""
 	case *Array:
@@ -323,8 +323,8 @@ func (x *operand) assignableTo(check *Checker, T Type, cause *string) (bool, Cod
 		return true, 0
 	}
 
-	Vu := under(V)
-	Tu := under(T)
+	Vu := V.Underlying()
+	Tu := T.Underlying()
 	Vp, _ := V.(*TypeParam)
 	Tp, _ := T.(*TypeParam)
 
diff --git a/src/go/types/predicates.go b/src/go/types/predicates.go
index 45f28726eecba6..ad929db2667eba 100644
--- a/src/go/types/predicates.go
+++ b/src/go/types/predicates.go
@@ -31,11 +31,11 @@ func isString(t Type) bool         { return isBasic(t, IsString) }
 func isIntegerOrFloat(t Type) bool { return isBasic(t, IsInteger|IsFloat) }
 func isConstType(t Type) bool      { return isBasic(t, IsConstType) }
 
-// isBasic reports whether under(t) is a basic type with the specified info.
+// isBasic reports whether t.Underlying() is a basic type with the specified info.
 // If t is a type parameter the result is false; i.e.,
 // isBasic does not look inside a type parameter.
 func isBasic(t Type, info BasicInfo) bool {
-	u, _ := under(t).(*Basic)
+	u, _ := t.Underlying().(*Basic)
 	return u != nil && u.info&info != 0
 }
 
@@ -51,7 +51,7 @@ func allString(t Type) bool          { return allBasic(t, IsString) }
 func allOrdered(t Type) bool         { return allBasic(t, IsOrdered) }
 func allNumericOrString(t Type) bool { return allBasic(t, IsNumeric|IsString) }
 
-// allBasic reports whether under(t) is a basic type with the specified info.
+// allBasic reports whether t.Underlying() is a basic type with the specified info.
 // If t is a type parameter, the result is true if isBasic(t, info) is true
 // for all specific types of the type parameter's type set.
 func allBasic(t Type, info BasicInfo) bool {
@@ -110,7 +110,7 @@ func isUntypedNumeric(t Type) bool {
 
 // IsInterface reports whether t is an interface type.
 func IsInterface(t Type) bool {
-	_, ok := under(t).(*Interface)
+	_, ok := t.Underlying().(*Interface)
 	return ok
 }
 
@@ -166,7 +166,7 @@ func comparableType(T Type, dynamic bool, seen map[Type]bool) *typeError {
 	}
 	seen[T] = true
 
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Basic:
 		// assume invalid types to be comparable to avoid follow-up errors
 		if t.kind == UntypedNil {
@@ -209,7 +209,7 @@ func comparableType(T Type, dynamic bool, seen map[Type]bool) *typeError {
 
 // hasNil reports whether type t includes the nil value.
 func hasNil(t Type) bool {
-	switch u := under(t).(type) {
+	switch u := t.Underlying().(type) {
 	case *Basic:
 		return u.kind == UnsafePointer
 	case *Slice, *Pointer, *Signature, *Map, *Chan:
diff --git a/src/go/types/range.go b/src/go/types/range.go
index 303d001c72d05b..d38150dea77480 100644
--- a/src/go/types/range.go
+++ b/src/go/types/range.go
@@ -38,7 +38,7 @@ func (check *Checker) rangeStmt(inner stmtContext, rangeStmt *ast.RangeStmt, noN
 	check.expr(nil, &x, rangeVar)
 
 	if isTypes2 && x.mode != invalid && sValue == nil && !check.hasCallOrRecv {
-		if t, ok := arrayPtrDeref(under(x.typ)).(*Array); ok {
+		if t, ok := arrayPtrDeref(x.typ.Underlying()).(*Array); ok {
 			for {
 				// Put constant info on the thing inside parentheses.
 				// That's where (*../noder/writer).expr expects it.
diff --git a/src/go/types/sizes.go b/src/go/types/sizes.go
index 51ea224f0b2997..e2ff047bc859c3 100644
--- a/src/go/types/sizes.go
+++ b/src/go/types/sizes.go
@@ -57,7 +57,7 @@ func (s *StdSizes) Alignof(T Type) (result int64) {
 
 	// For arrays and structs, alignment is defined in terms
 	// of alignment of the elements and fields, respectively.
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Array:
 		// spec: "For a variable x of array type: unsafe.Alignof(x)
 		// is the same as unsafe.Alignof(x[0]), but at least 1."
@@ -165,7 +165,7 @@ var basicSizes = [...]byte{
 }
 
 func (s *StdSizes) Sizeof(T Type) int64 {
-	switch t := under(T).(type) {
+	switch t := T.Underlying().(type) {
 	case *Basic:
 		assert(isTyped(T))
 		k := t.kind
@@ -310,7 +310,7 @@ func (conf *Config) offsetsof(T *Struct) []int64 {
 func (conf *Config) offsetof(T Type, index []int) int64 {
 	var offs int64
 	for _, i := range index {
-		s := under(T).(*Struct)
+		s := T.Underlying().(*Struct)
 		d := conf.offsetsof(s)[i]
 		if d < 0 {
 			return -1
diff --git a/src/go/types/struct.go b/src/go/types/struct.go
index a6970832c7c0d4..0133eb450db6d7 100644
--- a/src/go/types/struct.go
+++ b/src/go/types/struct.go
@@ -137,7 +137,7 @@ func (check *Checker) structType(styp *Struct, e *ast.StructType) {
 			// Because we have a name, typ must be of the form T or *T, where T is the name
 			// of a (named or alias) type, and t (= deref(typ)) must be the type of T.
 			// We must delay this check to the end because we don't want to instantiate
-			// (via under(t)) a possibly incomplete type.
+			// (via t.Underlying()) a possibly incomplete type.
 
 			// for use in the closure below
 			embeddedTyp := typ
@@ -145,7 +145,7 @@ func (check *Checker) structType(styp *Struct, e *ast.StructType) {
 
 			check.later(func() {
 				t, isPtr := deref(embeddedTyp)
-				switch u := under(t).(type) {
+				switch u := t.Underlying().(type) {
 				case *Basic:
 					if !isValid(t) {
 						// error was reported before
diff --git a/src/go/types/typeparam.go b/src/go/types/typeparam.go
index 2ffef8f613319a..eafcb1c145d1f8 100644
--- a/src/go/types/typeparam.go
+++ b/src/go/types/typeparam.go
@@ -116,7 +116,7 @@ func (t *TypeParam) iface() *Interface {
 
 	// determine constraint interface
 	var ityp *Interface
-	switch u := under(bound).(type) {
+	switch u := bound.Underlying().(type) {
 	case *Basic:
 		if !isValid(u) {
 			// error is reported elsewhere
diff --git a/src/go/types/typeset.go b/src/go/types/typeset.go
index 46ed5ce1802e0b..3a61c307561963 100644
--- a/src/go/types/typeset.go
+++ b/src/go/types/typeset.go
@@ -117,13 +117,13 @@ func (s *_TypeSet) all(f func(t, u Type) bool) bool {
 
 	for _, t := range s.terms {
 		assert(t.typ != nil)
-		// Unalias(x) == under(x) for ~x terms
+		// Unalias(x) == x.Underlying() for ~x terms
 		u := Unalias(t.typ)
 		if !t.tilde {
-			u = under(u)
+			u = u.Underlying()
 		}
 		if debug {
-			assert(Identical(u, under(u)))
+			assert(Identical(u, u.Underlying()))
 		}
 		if !f(t.typ, u) {
 			return false
@@ -267,7 +267,7 @@ func computeInterfaceTypeSet(check *Checker, pos token.Pos, ityp *Interface) *_T
 		}
 		var comparable bool
 		var terms termlist
-		switch u := under(typ).(type) {
+		switch u := typ.Underlying().(type) {
 		case *Interface:
 			// For now we don't permit type parameters as constraints.
 			assert(!isTypeParam(typ))
@@ -383,7 +383,7 @@ func computeUnionTypeSet(check *Checker, unionSets map[*Union]*_TypeSet, pos tok
 	var allTerms termlist
 	for _, t := range utyp.terms {
 		var terms termlist
-		u := under(t.typ)
+		u := t.typ.Underlying()
 		if ui, _ := u.(*Interface); ui != nil {
 			// For now we don't permit type parameters as constraints.
 			assert(!isTypeParam(t.typ))
diff --git a/src/go/types/typeset_test.go b/src/go/types/typeset_test.go
index 51560924839eae..a4feb7469b0637 100644
--- a/src/go/types/typeset_test.go
+++ b/src/go/types/typeset_test.go
@@ -65,7 +65,7 @@ func TestTypeSetString(t *testing.T) {
 		if obj == nil {
 			t.Fatalf("%s: T not found (invalid test case)", body)
 		}
-		T, ok := under(obj.Type()).(*Interface)
+		T, ok := obj.Type().Underlying().(*Interface)
 		if !ok {
 			t.Fatalf("%s: %v is not an interface (invalid test case)", body, obj)
 		}
diff --git a/src/go/types/typestring.go b/src/go/types/typestring.go
index 804e80407ef52a..bd13459832deca 100644
--- a/src/go/types/typestring.go
+++ b/src/go/types/typestring.go
@@ -458,7 +458,7 @@ func (w *typeWriter) tuple(tup *Tuple, variadic bool) {
 				} else {
 					// special case:
 					// append(s, "foo"...) leads to signature func([]byte, string...)
-					if t, _ := under(typ).(*Basic); t == nil || t.kind != String {
+					if t, _ := typ.Underlying().(*Basic); t == nil || t.kind != String {
 						w.error("expected string type")
 						continue
 					}
diff --git a/src/go/types/typeterm.go b/src/go/types/typeterm.go
index 1cd4e1651f30cd..b9ba8f38f91c83 100644
--- a/src/go/types/typeterm.go
+++ b/src/go/types/typeterm.go
@@ -118,7 +118,7 @@ func (x *term) includes(t Type) bool {
 
 	u := t
 	if x.tilde {
-		u = under(u)
+		u = u.Underlying()
 	}
 	return Identical(x.typ, u)
 }
@@ -158,11 +158,11 @@ func (x *term) disjoint(y *term) bool {
 	}
 	ux := x.typ
 	if y.tilde {
-		ux = under(ux)
+		ux = ux.Underlying()
 	}
 	uy := y.typ
 	if x.tilde {
-		uy = under(uy)
+		uy = uy.Underlying()
 	}
 	return !Identical(ux, uy)
 }
diff --git a/src/go/types/typexpr.go b/src/go/types/typexpr.go
index 2e45b7570f3677..88ec4b77fca7e9 100644
--- a/src/go/types/typexpr.go
+++ b/src/go/types/typexpr.go
@@ -168,11 +168,11 @@ func (check *Checker) validVarType(e ast.Expr, typ Type) {
 		return
 	}
 
-	// We don't want to call under() or complete interfaces while we are in
+	// We don't want to call typ.Underlying() or complete interfaces while we are in
 	// the middle of type-checking parameter declarations that might belong
 	// to interface methods. Delay this check to the end of type-checking.
 	check.later(func() {
-		if t, _ := under(typ).(*Interface); t != nil {
+		if t, _ := typ.Underlying().(*Interface); t != nil {
 			tset := computeInterfaceTypeSet(check, e.Pos(), t) // TODO(gri) is this the correct position?
 			if !tset.IsMethodSet() {
 				if tset.comparable {
@@ -237,7 +237,7 @@ func (check *Checker) typInternal(e0 ast.Expr, def *TypeName) (T Type) {
 			check.indent--
 			var under Type
 			if T != nil {
-				// Calling under() here may lead to endless instantiations.
+				// Calling T.Underlying() here may lead to endless instantiations.
 				// Test case: type T[P any] *T[P]
 				under = safeUnderlying(T)
 			}
diff --git a/src/go/types/under.go b/src/go/types/under.go
index d5e476a79f4739..6056b2e4829d3b 100644
--- a/src/go/types/under.go
+++ b/src/go/types/under.go
@@ -9,17 +9,8 @@ package types
 
 import "iter"
 
-// under returns the true expanded underlying type.
-// If it doesn't exist, the result is Typ[Invalid].
-// under must only be called when a type is known
-// to be fully set up.
-func under(t Type) Type {
-	// TODO(markfreeman): Remove this function, it just delegates.
-	return t.Underlying()
-}
-
 // If typ is a type parameter, underIs returns the result of typ.underIs(f).
-// Otherwise, underIs returns the result of f(under(typ)).
+// Otherwise, underIs returns the result of f(typ.Underlying()).
 func underIs(typ Type, f func(Type) bool) bool {
 	return all(typ, func(_, u Type) bool {
 		return f(u)
@@ -32,7 +23,7 @@ func all(t Type, f func(t, u Type) bool) bool {
 	if p, _ := Unalias(t).(*TypeParam); p != nil {
 		return p.typeset(f)
 	}
-	return f(t, under(t))
+	return f(t, t.Underlying())
 }
 
 // typeset is an iterator over the (type/underlying type) pairs of the
diff --git a/src/go/types/unify.go b/src/go/types/unify.go
index 2e3ba512df70c9..ea96de82f0f297 100644
--- a/src/go/types/unify.go
+++ b/src/go/types/unify.go
@@ -273,7 +273,7 @@ func (u *unifier) inferred(tparams []*TypeParam) []Type {
 // it is a non-type parameter interface. Otherwise it returns nil.
 func asInterface(x Type) (i *Interface) {
 	if _, ok := Unalias(x).(*TypeParam); !ok {
-		i, _ = under(x).(*Interface)
+		i, _ = x.Underlying().(*Interface)
 	}
 	return i
 }
@@ -433,7 +433,7 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
 						u.set(px, y)
 					default:
 						// Neither x nor y are defined types.
-						if yc, _ := under(y).(*Chan); yc != nil && yc.dir != SendRecv {
+						if yc, _ := y.Underlying().(*Chan); yc != nil && yc.dir != SendRecv {
 							// y is a directed channel type: select y.
 							u.set(px, y)
 						}
diff --git a/src/go/types/union.go b/src/go/types/union.go
index 30365e30bc2a06..3f7efdf1f38a9d 100644
--- a/src/go/types/union.go
+++ b/src/go/types/union.go
@@ -94,7 +94,7 @@ func parseUnion(check *Checker, uexpr ast.Expr) Type {
 				continue
 			}
 
-			u := under(t.typ)
+			u := t.typ.Underlying()
 			f, _ := u.(*Interface)
 			if t.tilde {
 				if f != nil {

From 36863d619400910a2728c07615afe91c17415ef4 Mon Sep 17 00:00:00 2001
From: qmuntal 
Date: Wed, 24 Sep 2025 10:13:44 +0200
Subject: [PATCH 167/229] runtime: unify riscv64 library entry point

Cq-Include-Trybots: luci.golang.try:gotip-linux-riscv64
Change-Id: I6470dfc5c9e03dfe5fc535605fdd7d861b9ba2f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/706415
Reviewed-by: Cherry Mui 
Reviewed-by: Keith Randall 
Reviewed-by: Joel Sing 
LUCI-TryBot-Result: Go LUCI 
---
 src/runtime/asm_riscv64.s         | 98 +++++++++++++++++++++++++++++++
 src/runtime/rt0_freebsd_riscv64.s | 96 +-----------------------------
 src/runtime/rt0_linux_riscv64.s   | 96 +-----------------------------
 3 files changed, 102 insertions(+), 188 deletions(-)

diff --git a/src/runtime/asm_riscv64.s b/src/runtime/asm_riscv64.s
index 6b16d03c9a8070..efe6047419e8b3 100644
--- a/src/runtime/asm_riscv64.s
+++ b/src/runtime/asm_riscv64.s
@@ -6,6 +6,104 @@
 #include "funcdata.h"
 #include "textflag.h"
 
+
+// When building with -buildmode=c-shared, this symbol is called when the shared
+// library is loaded.
+TEXT _rt0_riscv64_lib(SB),NOSPLIT,$224
+	// Preserve callee-save registers, along with X1 (LR).
+	MOV	X1, (8*3)(X2)
+	MOV	X8, (8*4)(X2)
+	MOV	X9, (8*5)(X2)
+	MOV	X18, (8*6)(X2)
+	MOV	X19, (8*7)(X2)
+	MOV	X20, (8*8)(X2)
+	MOV	X21, (8*9)(X2)
+	MOV	X22, (8*10)(X2)
+	MOV	X23, (8*11)(X2)
+	MOV	X24, (8*12)(X2)
+	MOV	X25, (8*13)(X2)
+	MOV	X26, (8*14)(X2)
+	MOV	g, (8*15)(X2)
+	MOVD	F8, (8*16)(X2)
+	MOVD	F9, (8*17)(X2)
+	MOVD	F18, (8*18)(X2)
+	MOVD	F19, (8*19)(X2)
+	MOVD	F20, (8*20)(X2)
+	MOVD	F21, (8*21)(X2)
+	MOVD	F22, (8*22)(X2)
+	MOVD	F23, (8*23)(X2)
+	MOVD	F24, (8*24)(X2)
+	MOVD	F25, (8*25)(X2)
+	MOVD	F26, (8*26)(X2)
+	MOVD	F27, (8*27)(X2)
+
+	// Initialize g as nil in case of using g later e.g. sigaction in cgo_sigaction.go
+	MOV	X0, g
+
+	MOV	A0, _rt0_riscv64_lib_argc<>(SB)
+	MOV	A1, _rt0_riscv64_lib_argv<>(SB)
+
+	// Synchronous initialization.
+	MOV	$runtime·libpreinit(SB), T0
+	JALR	RA, T0
+
+	// Create a new thread to do the runtime initialization and return.
+	MOV	_cgo_sys_thread_create(SB), T0
+	BEQZ	T0, nocgo
+	MOV	$_rt0_riscv64_lib_go(SB), A0
+	MOV	$0, A1
+	JALR	RA, T0
+	JMP	restore
+
+nocgo:
+	MOV	$0x800000, A0                     // stacksize = 8192KB
+	MOV	$_rt0_riscv64_lib_go(SB), A1
+	MOV	A0, 8(X2)
+	MOV	A1, 16(X2)
+	MOV	$runtime·newosproc0(SB), T0
+	JALR	RA, T0
+
+restore:
+	// Restore callee-save registers, along with X1 (LR).
+	MOV	(8*3)(X2), X1
+	MOV	(8*4)(X2), X8
+	MOV	(8*5)(X2), X9
+	MOV	(8*6)(X2), X18
+	MOV	(8*7)(X2), X19
+	MOV	(8*8)(X2), X20
+	MOV	(8*9)(X2), X21
+	MOV	(8*10)(X2), X22
+	MOV	(8*11)(X2), X23
+	MOV	(8*12)(X2), X24
+	MOV	(8*13)(X2), X25
+	MOV	(8*14)(X2), X26
+	MOV	(8*15)(X2), g
+	MOVD	(8*16)(X2), F8
+	MOVD	(8*17)(X2), F9
+	MOVD	(8*18)(X2), F18
+	MOVD	(8*19)(X2), F19
+	MOVD	(8*20)(X2), F20
+	MOVD	(8*21)(X2), F21
+	MOVD	(8*22)(X2), F22
+	MOVD	(8*23)(X2), F23
+	MOVD	(8*24)(X2), F24
+	MOVD	(8*25)(X2), F25
+	MOVD	(8*26)(X2), F26
+	MOVD	(8*27)(X2), F27
+
+	RET
+
+TEXT _rt0_riscv64_lib_go(SB),NOSPLIT,$0
+	MOV	_rt0_riscv64_lib_argc<>(SB), A0
+	MOV	_rt0_riscv64_lib_argv<>(SB), A1
+	MOV	$runtime·rt0_go(SB), T0
+	JALR	ZERO, T0
+
+DATA _rt0_riscv64_lib_argc<>(SB)/8, $0
+GLOBL _rt0_riscv64_lib_argc<>(SB),NOPTR, $8
+DATA _rt0_riscv64_lib_argv<>(SB)/8, $0
+GLOBL _rt0_riscv64_lib_argv<>(SB),NOPTR, $8
+
 // func rt0_go()
 TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 	// X2 = stack; A0 = argc; A1 = argv
diff --git a/src/runtime/rt0_freebsd_riscv64.s b/src/runtime/rt0_freebsd_riscv64.s
index dc46b7047669ad..f3fb4ffbe75ffd 100644
--- a/src/runtime/rt0_freebsd_riscv64.s
+++ b/src/runtime/rt0_freebsd_riscv64.s
@@ -12,100 +12,8 @@ TEXT _rt0_riscv64_freebsd(SB),NOSPLIT|NOFRAME,$0
 
 // When building with -buildmode=c-shared, this symbol is called when the shared
 // library is loaded.
-TEXT _rt0_riscv64_freebsd_lib(SB),NOSPLIT,$224
-	// Preserve callee-save registers, along with X1 (LR).
-	MOV	X1, (8*3)(X2)
-	MOV	X8, (8*4)(X2)
-	MOV	X9, (8*5)(X2)
-	MOV	X18, (8*6)(X2)
-	MOV	X19, (8*7)(X2)
-	MOV	X20, (8*8)(X2)
-	MOV	X21, (8*9)(X2)
-	MOV	X22, (8*10)(X2)
-	MOV	X23, (8*11)(X2)
-	MOV	X24, (8*12)(X2)
-	MOV	X25, (8*13)(X2)
-	MOV	X26, (8*14)(X2)
-	MOV	g, (8*15)(X2)
-	MOVD	F8, (8*16)(X2)
-	MOVD	F9, (8*17)(X2)
-	MOVD	F18, (8*18)(X2)
-	MOVD	F19, (8*19)(X2)
-	MOVD	F20, (8*20)(X2)
-	MOVD	F21, (8*21)(X2)
-	MOVD	F22, (8*22)(X2)
-	MOVD	F23, (8*23)(X2)
-	MOVD	F24, (8*24)(X2)
-	MOVD	F25, (8*25)(X2)
-	MOVD	F26, (8*26)(X2)
-	MOVD	F27, (8*27)(X2)
-
-	// Initialize g as nil in case of using g later e.g. sigaction in cgo_sigaction.go
-	MOV	X0, g
-
-	MOV	A0, _rt0_riscv64_freebsd_lib_argc<>(SB)
-	MOV	A1, _rt0_riscv64_freebsd_lib_argv<>(SB)
-
-	// Synchronous initialization.
-	MOV	$runtime·libpreinit(SB), T0
-	JALR	RA, T0
-
-	// Create a new thread to do the runtime initialization and return.
-	MOV	_cgo_sys_thread_create(SB), T0
-	BEQZ	T0, nocgo
-	MOV	$_rt0_riscv64_freebsd_lib_go(SB), A0
-	MOV	$0, A1
-	JALR	RA, T0
-	JMP	restore
-
-nocgo:
-	MOV	$0x800000, A0                     // stacksize = 8192KB
-	MOV	$_rt0_riscv64_freebsd_lib_go(SB), A1
-	MOV	A0, 8(X2)
-	MOV	A1, 16(X2)
-	MOV	$runtime·newosproc0(SB), T0
-	JALR	RA, T0
-
-restore:
-	// Restore callee-save registers, along with X1 (LR).
-	MOV	(8*3)(X2), X1
-	MOV	(8*4)(X2), X8
-	MOV	(8*5)(X2), X9
-	MOV	(8*6)(X2), X18
-	MOV	(8*7)(X2), X19
-	MOV	(8*8)(X2), X20
-	MOV	(8*9)(X2), X21
-	MOV	(8*10)(X2), X22
-	MOV	(8*11)(X2), X23
-	MOV	(8*12)(X2), X24
-	MOV	(8*13)(X2), X25
-	MOV	(8*14)(X2), X26
-	MOV	(8*15)(X2), g
-	MOVD	(8*16)(X2), F8
-	MOVD	(8*17)(X2), F9
-	MOVD	(8*18)(X2), F18
-	MOVD	(8*19)(X2), F19
-	MOVD	(8*20)(X2), F20
-	MOVD	(8*21)(X2), F21
-	MOVD	(8*22)(X2), F22
-	MOVD	(8*23)(X2), F23
-	MOVD	(8*24)(X2), F24
-	MOVD	(8*25)(X2), F25
-	MOVD	(8*26)(X2), F26
-	MOVD	(8*27)(X2), F27
-
-	RET
-
-TEXT _rt0_riscv64_freebsd_lib_go(SB),NOSPLIT,$0
-	MOV	_rt0_riscv64_freebsd_lib_argc<>(SB), A0
-	MOV	_rt0_riscv64_freebsd_lib_argv<>(SB), A1
-	MOV	$runtime·rt0_go(SB), T0
-	JALR	ZERO, T0
-
-DATA _rt0_riscv64_freebsd_lib_argc<>(SB)/8, $0
-GLOBL _rt0_riscv64_freebsd_lib_argc<>(SB),NOPTR, $8
-DATA _rt0_riscv64_freebsd_lib_argv<>(SB)/8, $0
-GLOBL _rt0_riscv64_freebsd_lib_argv<>(SB),NOPTR, $8
+TEXT _rt0_riscv64_freebsd_lib(SB),NOSPLIT,$0
+	JMP	_rt0_riscv64_lib(SB)
 
 TEXT main(SB),NOSPLIT|NOFRAME,$0
 	MOV	$runtime·rt0_go(SB), T0
diff --git a/src/runtime/rt0_linux_riscv64.s b/src/runtime/rt0_linux_riscv64.s
index d6b8ac85dca646..4139c9bcecdc62 100644
--- a/src/runtime/rt0_linux_riscv64.s
+++ b/src/runtime/rt0_linux_riscv64.s
@@ -11,100 +11,8 @@ TEXT _rt0_riscv64_linux(SB),NOSPLIT|NOFRAME,$0
 
 // When building with -buildmode=c-shared, this symbol is called when the shared
 // library is loaded.
-TEXT _rt0_riscv64_linux_lib(SB),NOSPLIT,$224
-	// Preserve callee-save registers, along with X1 (LR).
-	MOV	X1, (8*3)(X2)
-	MOV	X8, (8*4)(X2)
-	MOV	X9, (8*5)(X2)
-	MOV	X18, (8*6)(X2)
-	MOV	X19, (8*7)(X2)
-	MOV	X20, (8*8)(X2)
-	MOV	X21, (8*9)(X2)
-	MOV	X22, (8*10)(X2)
-	MOV	X23, (8*11)(X2)
-	MOV	X24, (8*12)(X2)
-	MOV	X25, (8*13)(X2)
-	MOV	X26, (8*14)(X2)
-	MOV	g, (8*15)(X2)
-	MOVD	F8, (8*16)(X2)
-	MOVD	F9, (8*17)(X2)
-	MOVD	F18, (8*18)(X2)
-	MOVD	F19, (8*19)(X2)
-	MOVD	F20, (8*20)(X2)
-	MOVD	F21, (8*21)(X2)
-	MOVD	F22, (8*22)(X2)
-	MOVD	F23, (8*23)(X2)
-	MOVD	F24, (8*24)(X2)
-	MOVD	F25, (8*25)(X2)
-	MOVD	F26, (8*26)(X2)
-	MOVD	F27, (8*27)(X2)
-
-	// Initialize g as nil in case of using g later e.g. sigaction in cgo_sigaction.go
-	MOV	X0, g
-
-	MOV	A0, _rt0_riscv64_linux_lib_argc<>(SB)
-	MOV	A1, _rt0_riscv64_linux_lib_argv<>(SB)
-
-	// Synchronous initialization.
-	MOV	$runtime·libpreinit(SB), T0
-	JALR	RA, T0
-
-	// Create a new thread to do the runtime initialization and return.
-	MOV	_cgo_sys_thread_create(SB), T0
-	BEQZ	T0, nocgo
-	MOV	$_rt0_riscv64_linux_lib_go(SB), A0
-	MOV	$0, A1
-	JALR	RA, T0
-	JMP	restore
-
-nocgo:
-	MOV	$0x800000, A0                     // stacksize = 8192KB
-	MOV	$_rt0_riscv64_linux_lib_go(SB), A1
-	MOV	A0, 8(X2)
-	MOV	A1, 16(X2)
-	MOV	$runtime·newosproc0(SB), T0
-	JALR	RA, T0
-
-restore:
-	// Restore callee-save registers, along with X1 (LR).
-	MOV	(8*3)(X2), X1
-	MOV	(8*4)(X2), X8
-	MOV	(8*5)(X2), X9
-	MOV	(8*6)(X2), X18
-	MOV	(8*7)(X2), X19
-	MOV	(8*8)(X2), X20
-	MOV	(8*9)(X2), X21
-	MOV	(8*10)(X2), X22
-	MOV	(8*11)(X2), X23
-	MOV	(8*12)(X2), X24
-	MOV	(8*13)(X2), X25
-	MOV	(8*14)(X2), X26
-	MOV	(8*15)(X2), g
-	MOVD	(8*16)(X2), F8
-	MOVD	(8*17)(X2), F9
-	MOVD	(8*18)(X2), F18
-	MOVD	(8*19)(X2), F19
-	MOVD	(8*20)(X2), F20
-	MOVD	(8*21)(X2), F21
-	MOVD	(8*22)(X2), F22
-	MOVD	(8*23)(X2), F23
-	MOVD	(8*24)(X2), F24
-	MOVD	(8*25)(X2), F25
-	MOVD	(8*26)(X2), F26
-	MOVD	(8*27)(X2), F27
-
-	RET
-
-TEXT _rt0_riscv64_linux_lib_go(SB),NOSPLIT,$0
-	MOV	_rt0_riscv64_linux_lib_argc<>(SB), A0
-	MOV	_rt0_riscv64_linux_lib_argv<>(SB), A1
-	MOV	$runtime·rt0_go(SB), T0
-	JALR	ZERO, T0
-
-DATA _rt0_riscv64_linux_lib_argc<>(SB)/8, $0
-GLOBL _rt0_riscv64_linux_lib_argc<>(SB),NOPTR, $8
-DATA _rt0_riscv64_linux_lib_argv<>(SB)/8, $0
-GLOBL _rt0_riscv64_linux_lib_argv<>(SB),NOPTR, $8
+TEXT _rt0_riscv64_linux_lib(SB),NOSPLIT,$0
+	JMP	_rt0_riscv64_lib(SB)
 
 
 TEXT main(SB),NOSPLIT|NOFRAME,$0

From 09830901714d8b3a2cc5fb33e87a81886b21ea24 Mon Sep 17 00:00:00 2001
From: Roland Shoemaker 
Date: Wed, 15 Oct 2025 10:45:04 -0700
Subject: [PATCH 168/229] encoding/pem: properly decode strange PEM data

When the passed byte slice has leading garbage, properly handle ignoring
it and continuing to parse the slice until we find a valid block (or
nothing).

Change-Id: I07e937d9c754fd71b028b99450b48f57b4464457
Reviewed-on: https://go-review.googlesource.com/c/go/+/712140
Reviewed-by: Damien Neil 
LUCI-TryBot-Result: Go LUCI 
---
 src/encoding/pem/pem.go      | 11 ++--
 src/encoding/pem/pem_test.go | 97 ++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+), 3 deletions(-)

diff --git a/src/encoding/pem/pem.go b/src/encoding/pem/pem.go
index 21887008ca2182..2356096ade24d2 100644
--- a/src/encoding/pem/pem.go
+++ b/src/encoding/pem/pem.go
@@ -91,7 +91,12 @@ func Decode(data []byte) (p *Block, rest []byte) {
 	// the byte array, we'll accept the start string without it.
 	rest = data
 
+	endTrailerIndex := 0
 	for {
+		// If we've already tried parsing a block, skip past the END we already
+		// saw.
+		rest = rest[endTrailerIndex:]
+
 		// Find the first END line, and then find the last BEGIN line before
 		// the end line. This lets us skip any repeated BEGIN lines that don't
 		// have a matching END.
@@ -99,10 +104,10 @@ func Decode(data []byte) (p *Block, rest []byte) {
 		if endIndex < 0 {
 			return nil, data
 		}
-		endTrailerIndex := endIndex + len(pemEnd)
+		endTrailerIndex = endIndex + len(pemEnd)
 		beginIndex := bytes.LastIndex(rest[:endIndex], pemStart[1:])
-		if beginIndex < 0 || beginIndex > 0 && rest[beginIndex-1] != '\n' {
-			return nil, data
+		if beginIndex < 0 || (beginIndex > 0 && rest[beginIndex-1] != '\n') {
+			continue
 		}
 		rest = rest[beginIndex+len(pemStart)-1:]
 		endIndex -= beginIndex + len(pemStart) - 1
diff --git a/src/encoding/pem/pem_test.go b/src/encoding/pem/pem_test.go
index 2c9b3eabcd1c12..5bdc2f66a7b3ab 100644
--- a/src/encoding/pem/pem_test.go
+++ b/src/encoding/pem/pem_test.go
@@ -639,3 +639,100 @@ func TestBadEncode(t *testing.T) {
 }
 
 func testingKey(s string) string { return strings.ReplaceAll(s, "TESTING KEY", "PRIVATE KEY") }
+
+func TestDecodeStrangeCases(t *testing.T) {
+	sentinelType := "TEST BLOCK"
+	sentinelBytes := []byte("hello")
+	for _, tc := range []struct {
+		name string
+		pem  string
+	}{
+		{
+			name: "invalid section (not base64)",
+			pem: `-----BEGIN COMMENT-----
+foo foo foo
+-----END COMMENT-----
+-----BEGIN TEST BLOCK-----
+aGVsbG8=
+-----END TEST BLOCK-----`,
+		},
+		{
+			name: "leading garbage on block",
+			pem: `foo foo foo-----BEGIN CERTIFICATE-----
+MCowBQYDK2VwAyEApVjJeLW5MoP6uR3+OeITokM+rBDng6dgl1vvhcy+wws=
+-----END PUBLIC KEY-----
+-----BEGIN TEST BLOCK-----
+aGVsbG8=
+-----END TEST BLOCK-----`,
+		},
+		{
+			name: "leading garbage",
+			pem: `foo foo foo
+-----BEGIN TEST BLOCK-----
+aGVsbG8=
+-----END TEST BLOCK-----`,
+		},
+		{
+			name: "leading partial block",
+			pem: `foo foo foo
+-----END COMMENT-----
+-----BEGIN TEST BLOCK-----
+aGVsbG8=
+-----END TEST BLOCK-----`,
+		},
+		{
+			name: "multiple BEGIN",
+			pem: `-----BEGIN TEST BLOCK-----
+-----BEGIN TEST BLOCK-----
+-----BEGIN TEST BLOCK-----
+aGVsbG8=
+-----END TEST BLOCK-----`,
+		},
+		{
+			name: "multiple END",
+			pem: `-----BEGIN TEST BLOCK-----
+aGVsbG8=
+-----END TEST BLOCK-----
+-----END TEST BLOCK-----
+-----END TEST BLOCK-----`,
+		},
+		{
+			name: "leading malformed BEGIN",
+			pem: `-----BEGIN PUBLIC KEY
+aGVsbG8=
+-----END PUBLIC KEY-----
+-----BEGIN TEST BLOCK-----
+aGVsbG8=
+-----END TEST BLOCK-----`,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			block, _ := Decode([]byte(tc.pem))
+			if block == nil {
+				t.Fatal("expected valid block")
+			}
+			if block.Type != sentinelType {
+				t.Fatalf("unexpected block returned, got type %q, want type %q", block.Type, sentinelType)
+			}
+			if !bytes.Equal(block.Bytes, sentinelBytes) {
+				t.Fatalf("unexpected block content, got %x, want %x", block.Bytes, sentinelBytes)
+			}
+		})
+	}
+}
+
+func TestJustEnd(t *testing.T) {
+	pemData := `
+-----END PUBLIC KEY-----`
+
+	block, _ := Decode([]byte(pemData))
+	if block != nil {
+		t.Fatal("unexpected block")
+	}
+}
+
+func FuzzDecode(f *testing.F) {
+	f.Fuzz(func(t *testing.T, data []byte) {
+		Decode(data)
+	})
+}

From dbbb1bfc912457abcd99eec1ffae74d52ecb55a5 Mon Sep 17 00:00:00 2001
From: Jes Cok 
Date: Thu, 16 Oct 2025 01:16:02 +0000
Subject: [PATCH 169/229] all: correct name for comments

Change-Id: I390c380349e99ad421264b673ad7734eddb639d3
GitHub-Last-Rev: 32e849a6420574b0d878b9a449a8c044fd6ebdd1
GitHub-Pull-Request: golang/go#75905
Reviewed-on: https://go-review.googlesource.com/c/go/+/711941
Reviewed-by: Jorropo 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
Auto-Submit: Jorropo 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Keith Randall 
Reviewed-by: Dmitri Shuralyov 
---
 src/cmd/compile/internal/bitvec/bv.go         | 2 +-
 src/cmd/compile/internal/ir/expr.go           | 4 ++--
 src/cmd/compile/internal/s390x/ggen.go        | 2 +-
 src/cmd/compile/internal/types/type.go        | 2 +-
 src/cmd/compile/internal/types2/object.go     | 2 +-
 src/cmd/go/internal/vet/vet.go                | 4 ++--
 src/cmd/internal/obj/x86/evex.go              | 2 +-
 src/cmd/internal/objfile/goobj.go             | 2 +-
 src/cmd/link/internal/loader/symbolbuilder.go | 2 +-
 src/crypto/internal/fips140/rsa/pkcs1v22.go   | 2 +-
 src/crypto/x509/oid.go                        | 2 +-
 src/debug/dwarf/entry.go                      | 2 +-
 src/go/scanner/scanner.go                     | 2 +-
 src/go/types/object.go                        | 2 +-
 src/internal/coverage/cmerge/merge.go         | 4 ++--
 src/internal/goarch/goarch.go                 | 2 +-
 src/internal/runtime/maps/table.go            | 2 +-
 src/internal/trace/event.go                   | 2 +-
 src/runtime/mspanset.go                       | 2 +-
 src/text/template/parse/parse.go              | 2 +-
 20 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/src/cmd/compile/internal/bitvec/bv.go b/src/cmd/compile/internal/bitvec/bv.go
index d3133dcd2dc679..9214aa6cd05560 100644
--- a/src/cmd/compile/internal/bitvec/bv.go
+++ b/src/cmd/compile/internal/bitvec/bv.go
@@ -93,7 +93,7 @@ func (bv BitVec) Unset(i int32) {
 	bv.B[i/wordBits] &^= mask
 }
 
-// bvnext returns the smallest index >= i for which bvget(bv, i) == 1.
+// Next returns the smallest index >= i for which bvget(bv, i) == 1.
 // If there is no such index, bvnext returns -1.
 func (bv BitVec) Next(i int32) int32 {
 	if i >= bv.N {
diff --git a/src/cmd/compile/internal/ir/expr.go b/src/cmd/compile/internal/ir/expr.go
index 037957b676a033..7a75ff40f2d609 100644
--- a/src/cmd/compile/internal/ir/expr.go
+++ b/src/cmd/compile/internal/ir/expr.go
@@ -617,7 +617,7 @@ func (o Op) IsSlice3() bool {
 	return false
 }
 
-// A SliceHeader expression constructs a slice header from its parts.
+// A SliceHeaderExpr constructs a slice header from its parts.
 type SliceHeaderExpr struct {
 	miniExpr
 	Ptr Node
@@ -665,7 +665,7 @@ func NewStarExpr(pos src.XPos, x Node) *StarExpr {
 func (n *StarExpr) Implicit() bool     { return n.flags&miniExprImplicit != 0 }
 func (n *StarExpr) SetImplicit(b bool) { n.flags.set(miniExprImplicit, b) }
 
-// A TypeAssertionExpr is a selector expression X.(Type).
+// A TypeAssertExpr is a selector expression X.(Type).
 // Before type-checking, the type is Ntype.
 type TypeAssertExpr struct {
 	miniExpr
diff --git a/src/cmd/compile/internal/s390x/ggen.go b/src/cmd/compile/internal/s390x/ggen.go
index 70e403122481e2..c4f88e782623e6 100644
--- a/src/cmd/compile/internal/s390x/ggen.go
+++ b/src/cmd/compile/internal/s390x/ggen.go
@@ -11,7 +11,7 @@ import (
 	"cmd/internal/obj/s390x"
 )
 
-// clearLoopCutOff is the (somewhat arbitrary) value above which it is better
+// clearLoopCutoff is the (somewhat arbitrary) value above which it is better
 // to have a loop of clear instructions (e.g. XCs) rather than just generating
 // multiple instructions (i.e. loop unrolling).
 // Must be between 256 and 4096.
diff --git a/src/cmd/compile/internal/types/type.go b/src/cmd/compile/internal/types/type.go
index 6a3e9b512e72d5..da859290f7a256 100644
--- a/src/cmd/compile/internal/types/type.go
+++ b/src/cmd/compile/internal/types/type.go
@@ -328,7 +328,7 @@ func (t *Type) funcType() *Func {
 	return t.extra.(*Func)
 }
 
-// StructType contains Type fields specific to struct types.
+// Struct contains Type fields specific to struct types.
 type Struct struct {
 	fields fields
 
diff --git a/src/cmd/compile/internal/types2/object.go b/src/cmd/compile/internal/types2/object.go
index 463ed30308d0ee..096b5653e53732 100644
--- a/src/cmd/compile/internal/types2/object.go
+++ b/src/cmd/compile/internal/types2/object.go
@@ -328,7 +328,7 @@ func (obj *TypeName) IsAlias() bool {
 	}
 }
 
-// A Variable represents a declared variable (including function parameters and results, and struct fields).
+// A Var represents a declared variable (including function parameters and results, and struct fields).
 type Var struct {
 	object
 	origin   *Var // if non-nil, the Var from which this one was instantiated
diff --git a/src/cmd/go/internal/vet/vet.go b/src/cmd/go/internal/vet/vet.go
index e274348bd6a38e..f9579d498f573a 100644
--- a/src/cmd/go/internal/vet/vet.go
+++ b/src/cmd/go/internal/vet/vet.go
@@ -396,7 +396,7 @@ type jsonError struct {
 	Err string `json:"error"`
 }
 
-// A TextEdit describes the replacement of a portion of a file.
+// A jsonTextEdit describes the replacement of a portion of a file.
 // Start and End are zero-based half-open indices into the original byte
 // sequence of the file, and New is the new text.
 type jsonTextEdit struct {
@@ -424,7 +424,7 @@ type jsonDiagnostic struct {
 	Related        []jsonRelatedInformation `json:"related,omitempty"`
 }
 
-// A jsonRelated describes a secondary position and message related to
+// A jsonRelatedInformation describes a secondary position and message related to
 // a primary diagnostic.
 type jsonRelatedInformation struct {
 	Posn    string `json:"posn"` // e.g. "file.go:line:column"
diff --git a/src/cmd/internal/obj/x86/evex.go b/src/cmd/internal/obj/x86/evex.go
index aa93cd8819ac20..12fe0347046f69 100644
--- a/src/cmd/internal/obj/x86/evex.go
+++ b/src/cmd/internal/obj/x86/evex.go
@@ -165,7 +165,7 @@ func evexZcase(zcase uint8) bool {
 	return zcase > Zevex_first && zcase < Zevex_last
 }
 
-// evexSuffixBits carries instruction EVEX suffix set flags.
+// evexSuffix carries instruction EVEX suffix set flags.
 //
 // Examples:
 //
diff --git a/src/cmd/internal/objfile/goobj.go b/src/cmd/internal/objfile/goobj.go
index e8b8b522516b9f..c428e29c9b19a4 100644
--- a/src/cmd/internal/objfile/goobj.go
+++ b/src/cmd/internal/objfile/goobj.go
@@ -227,7 +227,7 @@ func (f *goobjFile) pcln() (textStart uint64, symtab, pclntab []byte, err error)
 	return 0, nil, nil, fmt.Errorf("pcln not available in go object file")
 }
 
-// Find returns the file name, line, and function data for the given pc.
+// PCToLine returns the file name, line, and function data for the given pc.
 // Returns "",0,nil if unknown.
 // This function implements the Liner interface in preference to pcln() above.
 func (f *goobjFile) PCToLine(pc uint64) (string, int, *gosym.Func) {
diff --git a/src/cmd/link/internal/loader/symbolbuilder.go b/src/cmd/link/internal/loader/symbolbuilder.go
index 35749f9ea9363e..d385dec94a19c6 100644
--- a/src/cmd/link/internal/loader/symbolbuilder.go
+++ b/src/cmd/link/internal/loader/symbolbuilder.go
@@ -139,7 +139,7 @@ func (sb *SymbolBuilder) SetRelocAdd(i int, a int64) {
 	sb.relocs[i].SetAdd(a)
 }
 
-// SetRelocAdd sets the size of the 'i'-th relocation on this sym to 'sz'
+// SetRelocSiz sets the size of the 'i'-th relocation on this sym to 'sz'
 func (sb *SymbolBuilder) SetRelocSiz(i int, sz uint8) {
 	sb.relocs[i].SetSiz(sz)
 }
diff --git a/src/crypto/internal/fips140/rsa/pkcs1v22.go b/src/crypto/internal/fips140/rsa/pkcs1v22.go
index de7943773e63ac..94e7345996a46f 100644
--- a/src/crypto/internal/fips140/rsa/pkcs1v22.go
+++ b/src/crypto/internal/fips140/rsa/pkcs1v22.go
@@ -316,7 +316,7 @@ func VerifyPSS(pub *PublicKey, hash hash.Hash, digest []byte, sig []byte) error
 	return verifyPSS(pub, hash, digest, sig, pssSaltLengthAutodetect)
 }
 
-// VerifyPSS verifies sig with RSASSA-PSS and an expected salt length.
+// VerifyPSSWithSaltLength verifies sig with RSASSA-PSS and an expected salt length.
 func VerifyPSSWithSaltLength(pub *PublicKey, hash hash.Hash, digest []byte, sig []byte, saltLength int) error {
 	if saltLength < 0 {
 		return errors.New("crypto/rsa: salt length cannot be negative")
diff --git a/src/crypto/x509/oid.go b/src/crypto/x509/oid.go
index b1464346b6b28a..c60daa7540c830 100644
--- a/src/crypto/x509/oid.go
+++ b/src/crypto/x509/oid.go
@@ -286,7 +286,7 @@ func (oid OID) EqualASN1OID(other asn1.ObjectIdentifier) bool {
 	return i == len(other)
 }
 
-// Strings returns the string representation of the Object Identifier.
+// String returns the string representation of the Object Identifier.
 func (oid OID) String() string {
 	var b strings.Builder
 	b.Grow(32)
diff --git a/src/debug/dwarf/entry.go b/src/debug/dwarf/entry.go
index 8741479483348e..30fad93e7937d2 100644
--- a/src/debug/dwarf/entry.go
+++ b/src/debug/dwarf/entry.go
@@ -229,7 +229,7 @@ func formToClass(form format, attr Attr, vers int, b *buf) Class {
 	}
 }
 
-// An entry is a sequence of attribute/value pairs.
+// An Entry is a sequence of attribute/value pairs.
 type Entry struct {
 	Offset   Offset // offset of Entry in DWARF info
 	Tag      Tag    // tag (kind of Entry)
diff --git a/src/go/scanner/scanner.go b/src/go/scanner/scanner.go
index 153252b5cc3ebd..cdbeb6323c6e80 100644
--- a/src/go/scanner/scanner.go
+++ b/src/go/scanner/scanner.go
@@ -107,7 +107,7 @@ func (s *Scanner) peek() byte {
 	return 0
 }
 
-// A mode value is a set of flags (or 0).
+// A Mode value is a set of flags (or 0).
 // They control scanner behavior.
 type Mode uint
 
diff --git a/src/go/types/object.go b/src/go/types/object.go
index 1bba5d52a8b2b6..27dcb71956dcb4 100644
--- a/src/go/types/object.go
+++ b/src/go/types/object.go
@@ -331,7 +331,7 @@ func (obj *TypeName) IsAlias() bool {
 	}
 }
 
-// A Variable represents a declared variable (including function parameters and results, and struct fields).
+// A Var represents a declared variable (including function parameters and results, and struct fields).
 type Var struct {
 	object
 	origin   *Var // if non-nil, the Var from which this one was instantiated
diff --git a/src/internal/coverage/cmerge/merge.go b/src/internal/coverage/cmerge/merge.go
index 1339803d0865c6..9fc548eced5091 100644
--- a/src/internal/coverage/cmerge/merge.go
+++ b/src/internal/coverage/cmerge/merge.go
@@ -57,7 +57,7 @@ func (m *Merger) MergeCounters(dst, src []uint32) (error, bool) {
 	return nil, ovf
 }
 
-// Saturating add does a saturating addition of 'dst' and 'src',
+// SaturatingAdd does a saturating addition of 'dst' and 'src',
 // returning added value or math.MaxUint32 if there is an overflow.
 // Overflows are recorded in case the client needs to track them.
 func (m *Merger) SaturatingAdd(dst, src uint32) uint32 {
@@ -68,7 +68,7 @@ func (m *Merger) SaturatingAdd(dst, src uint32) uint32 {
 	return result
 }
 
-// Saturating add does a saturating addition of 'dst' and 'src',
+// SaturatingAdd does a saturating addition of 'dst' and 'src',
 // returning added value or math.MaxUint32 plus an overflow flag.
 func SaturatingAdd(dst, src uint32) (uint32, bool) {
 	d, s := uint64(dst), uint64(src)
diff --git a/src/internal/goarch/goarch.go b/src/internal/goarch/goarch.go
index 4da56dda9dadc1..efcf298d3b7b35 100644
--- a/src/internal/goarch/goarch.go
+++ b/src/internal/goarch/goarch.go
@@ -34,7 +34,7 @@ const (
 // It is also the size of the machine's native word size (that is, 4 on 32-bit systems, 8 on 64-bit).
 const PtrSize = 4 << (^uintptr(0) >> 63)
 
-// PtrSize is bit width of a pointer.
+// PtrBits is bit width of a pointer.
 const PtrBits = PtrSize * 8
 
 // ArchFamily is the architecture family (AMD64, ARM, ...)
diff --git a/src/internal/runtime/maps/table.go b/src/internal/runtime/maps/table.go
index 73ea76766bad0f..d9bcf23dfa04ed 100644
--- a/src/internal/runtime/maps/table.go
+++ b/src/internal/runtime/maps/table.go
@@ -716,7 +716,7 @@ func (it *Iter) Key() unsafe.Pointer {
 	return it.key
 }
 
-// Key returns a pointer to the current element. nil indicates end of
+// Elem returns a pointer to the current element. nil indicates end of
 // iteration.
 //
 // Must not be called prior to Next.
diff --git a/src/internal/trace/event.go b/src/internal/trace/event.go
index 321e4e21fb35fc..b78e52329469d3 100644
--- a/src/internal/trace/event.go
+++ b/src/internal/trace/event.go
@@ -197,7 +197,7 @@ type Range struct {
 	Scope ResourceID
 }
 
-// RangeAttributes provides attributes about a completed Range.
+// RangeAttribute provides attributes about a completed Range.
 type RangeAttribute struct {
 	// Name is the human-readable name for the range.
 	Name string
diff --git a/src/runtime/mspanset.go b/src/runtime/mspanset.go
index 21b105194e408a..f0fb06286202f9 100644
--- a/src/runtime/mspanset.go
+++ b/src/runtime/mspanset.go
@@ -407,7 +407,7 @@ func (p *atomicMSpanPointer) Load() *mspan {
 	return (*mspan)(p.p.Load())
 }
 
-// Store stores an *mspan.
+// StoreNoWB stores an *mspan.
 func (p *atomicMSpanPointer) StoreNoWB(s *mspan) {
 	p.p.StoreNoWB(unsafe.Pointer(s))
 }
diff --git a/src/text/template/parse/parse.go b/src/text/template/parse/parse.go
index 84d639d78d16a9..b74dfb7f4eaa5c 100644
--- a/src/text/template/parse/parse.go
+++ b/src/text/template/parse/parse.go
@@ -35,7 +35,7 @@ type Tree struct {
 	stackDepth int // depth of nested parenthesized expressions
 }
 
-// A mode value is a set of flags (or 0). Modes control parser behavior.
+// A Mode value is a set of flags (or 0). Modes control parser behavior.
 type Mode uint
 
 const (

From 5137c473b64cb157380eb6deb1b60bf6780402b3 Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Thu, 16 Oct 2025 16:09:11 -0700
Subject: [PATCH 170/229] go/types, types2: remove references to under function
 in comments

Follow-up on CL 712400 which removed the under function.

Change-Id: I253c8adbbaa058150f26e311e37b4c1644b6554d
Reviewed-on: https://go-review.googlesource.com/c/go/+/712520
Reviewed-by: Mark Freeman 
Reviewed-by: Robert Griesemer 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Robert Griesemer 
---
 src/cmd/compile/internal/types2/call.go       | 2 +-
 src/cmd/compile/internal/types2/infer.go      | 2 +-
 src/cmd/compile/internal/types2/lookup.go     | 4 ++--
 src/cmd/compile/internal/types2/named.go      | 4 ++--
 src/cmd/compile/internal/types2/predicates.go | 6 +++---
 src/cmd/compile/internal/types2/unify.go      | 2 +-
 src/go/types/call.go                          | 2 +-
 src/go/types/infer.go                         | 2 +-
 src/go/types/lookup.go                        | 4 ++--
 src/go/types/named.go                         | 4 ++--
 src/go/types/predicates.go                    | 6 +++---
 src/go/types/unify.go                         | 2 +-
 12 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/src/cmd/compile/internal/types2/call.go b/src/cmd/compile/internal/types2/call.go
index aca205ad985013..7128ad78668e9b 100644
--- a/src/cmd/compile/internal/types2/call.go
+++ b/src/cmd/compile/internal/types2/call.go
@@ -57,7 +57,7 @@ func (check *Checker) funcInst(T *target, pos syntax.Pos, x *operand, inst *synt
 
 	// Check the number of type arguments (got) vs number of type parameters (want).
 	// Note that x is a function value, not a type expression, so we don't need to
-	// call under below.
+	// call Underlying below.
 	sig := x.typ.(*Signature)
 	got, want := len(targs), sig.TypeParams().Len()
 	if got > want {
diff --git a/src/cmd/compile/internal/types2/infer.go b/src/cmd/compile/internal/types2/infer.go
index e7c59597372413..996f6a51090585 100644
--- a/src/cmd/compile/internal/types2/infer.go
+++ b/src/cmd/compile/internal/types2/infer.go
@@ -427,7 +427,7 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
 				// Note that if t0 was a signature, t1 must be a signature, and t1
 				// can only be a generic signature if it originated from a generic
 				// function argument. Those signatures are never defined types and
-				// thus there is no need to call under below.
+				// thus there is no need to call Underlying below.
 				// TODO(gri) Consider doing this in Checker.subst.
 				//           Then this would fall out automatically here and also
 				//           in instantiation (where we also explicitly nil out
diff --git a/src/cmd/compile/internal/types2/lookup.go b/src/cmd/compile/internal/types2/lookup.go
index 0b9282e1a7cfc2..3e18db09f5c498 100644
--- a/src/cmd/compile/internal/types2/lookup.go
+++ b/src/cmd/compile/internal/types2/lookup.go
@@ -145,8 +145,8 @@ func lookupFieldOrMethodImpl(T Type, addressable bool, pkg *Package, name string
 		return // blank fields/methods are never found
 	}
 
-	// Importantly, we must not call under before the call to deref below (nor
-	// does deref call under), as doing so could incorrectly result in finding
+	// Importantly, we must not call Underlying before the call to deref below (nor
+	// does deref call Underlying), as doing so could incorrectly result in finding
 	// methods of the pointer base type when T is a (*Named) pointer type.
 	typ, isPtr := deref(T)
 
diff --git a/src/cmd/compile/internal/types2/named.go b/src/cmd/compile/internal/types2/named.go
index 4a28929c513a9b..80247e63ded8c8 100644
--- a/src/cmd/compile/internal/types2/named.go
+++ b/src/cmd/compile/internal/types2/named.go
@@ -521,8 +521,8 @@ func (n *Named) Underlying() Type {
 	n.resolve()
 
 	// The gccimporter depends on writing a nil underlying via NewNamed and
-	// immediately reading it back. Rather than putting that in under() and
-	// complicating things there, we just check for that special case here.
+	// immediately reading it back. Rather than putting that in Named.under
+	// and complicating things there, we just check for that special case here.
 	if n.fromRHS == nil {
 		assert(n.allowNilRHS)
 		if n.allowNilUnderlying {
diff --git a/src/cmd/compile/internal/types2/predicates.go b/src/cmd/compile/internal/types2/predicates.go
index 60147c5e21138c..b0578c2991c9bb 100644
--- a/src/cmd/compile/internal/types2/predicates.go
+++ b/src/cmd/compile/internal/types2/predicates.go
@@ -85,7 +85,7 @@ func isTypeLit(t Type) bool {
 // Safe to call from types that are not fully set up.
 func isTyped(t Type) bool {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	b, _ := t.(*Basic)
 	return b == nil || b.info&IsUntyped == 0
 }
@@ -100,7 +100,7 @@ func isUntyped(t Type) bool {
 // Safe to call from types that are not fully set up.
 func isUntypedNumeric(t Type) bool {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	b, _ := t.(*Basic)
 	return b != nil && b.info&IsUntyped != 0 && b.info&IsNumeric != 0
 }
@@ -519,7 +519,7 @@ func identicalInstance(xorig Type, xargs []Type, yorig Type, yargs []Type) bool
 // for untyped nil is untyped nil.
 func Default(t Type) Type {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	if t, _ := t.(*Basic); t != nil {
 		switch t.kind {
 		case UntypedBool:
diff --git a/src/cmd/compile/internal/types2/unify.go b/src/cmd/compile/internal/types2/unify.go
index eecef455ac577c..f4f24f4d1b7ec0 100644
--- a/src/cmd/compile/internal/types2/unify.go
+++ b/src/cmd/compile/internal/types2/unify.go
@@ -779,7 +779,7 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
 				}
 				// If y is a defined type, it may not match against cx which
 				// is an underlying type (incl. int, string, etc.). Use assign
-				// mode here so that the unifier automatically takes under(y)
+				// mode here so that the unifier automatically uses y.Underlying()
 				// if necessary.
 				return u.nify(cx, yorig, assign, p)
 			}
diff --git a/src/go/types/call.go b/src/go/types/call.go
index 44549b8727cf0b..98498763c82516 100644
--- a/src/go/types/call.go
+++ b/src/go/types/call.go
@@ -58,7 +58,7 @@ func (check *Checker) funcInst(T *target, pos token.Pos, x *operand, ix *indexed
 
 	// Check the number of type arguments (got) vs number of type parameters (want).
 	// Note that x is a function value, not a type expression, so we don't need to
-	// call under below.
+	// call Underlying below.
 	sig := x.typ.(*Signature)
 	got, want := len(targs), sig.TypeParams().Len()
 	if got > want {
diff --git a/src/go/types/infer.go b/src/go/types/infer.go
index a8da7ac674abf9..25a26b38a5eadf 100644
--- a/src/go/types/infer.go
+++ b/src/go/types/infer.go
@@ -430,7 +430,7 @@ func (check *Checker) infer(posn positioner, tparams []*TypeParam, targs []Type,
 				// Note that if t0 was a signature, t1 must be a signature, and t1
 				// can only be a generic signature if it originated from a generic
 				// function argument. Those signatures are never defined types and
-				// thus there is no need to call under below.
+				// thus there is no need to call Underlying below.
 				// TODO(gri) Consider doing this in Checker.subst.
 				//           Then this would fall out automatically here and also
 				//           in instantiation (where we also explicitly nil out
diff --git a/src/go/types/lookup.go b/src/go/types/lookup.go
index c479303a350b8c..97debb7395e129 100644
--- a/src/go/types/lookup.go
+++ b/src/go/types/lookup.go
@@ -148,8 +148,8 @@ func lookupFieldOrMethodImpl(T Type, addressable bool, pkg *Package, name string
 		return // blank fields/methods are never found
 	}
 
-	// Importantly, we must not call under before the call to deref below (nor
-	// does deref call under), as doing so could incorrectly result in finding
+	// Importantly, we must not call Underlying before the call to deref below (nor
+	// does deref call Underlying), as doing so could incorrectly result in finding
 	// methods of the pointer base type when T is a (*Named) pointer type.
 	typ, isPtr := deref(T)
 
diff --git a/src/go/types/named.go b/src/go/types/named.go
index d7e4c2479634fc..faa7bc2a706a3c 100644
--- a/src/go/types/named.go
+++ b/src/go/types/named.go
@@ -524,8 +524,8 @@ func (n *Named) Underlying() Type {
 	n.resolve()
 
 	// The gccimporter depends on writing a nil underlying via NewNamed and
-	// immediately reading it back. Rather than putting that in under() and
-	// complicating things there, we just check for that special case here.
+	// immediately reading it back. Rather than putting that in Named.under
+	// and complicating things there, we just check for that special case here.
 	if n.fromRHS == nil {
 		assert(n.allowNilRHS)
 		if n.allowNilUnderlying {
diff --git a/src/go/types/predicates.go b/src/go/types/predicates.go
index ad929db2667eba..7a48c2c96c263f 100644
--- a/src/go/types/predicates.go
+++ b/src/go/types/predicates.go
@@ -88,7 +88,7 @@ func isTypeLit(t Type) bool {
 // Safe to call from types that are not fully set up.
 func isTyped(t Type) bool {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	b, _ := t.(*Basic)
 	return b == nil || b.info&IsUntyped == 0
 }
@@ -103,7 +103,7 @@ func isUntyped(t Type) bool {
 // Safe to call from types that are not fully set up.
 func isUntypedNumeric(t Type) bool {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	b, _ := t.(*Basic)
 	return b != nil && b.info&IsUntyped != 0 && b.info&IsNumeric != 0
 }
@@ -522,7 +522,7 @@ func identicalInstance(xorig Type, xargs []Type, yorig Type, yargs []Type) bool
 // for untyped nil is untyped nil.
 func Default(t Type) Type {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	if t, _ := t.(*Basic); t != nil {
 		switch t.kind {
 		case UntypedBool:
diff --git a/src/go/types/unify.go b/src/go/types/unify.go
index ea96de82f0f297..3b52e6e1e67350 100644
--- a/src/go/types/unify.go
+++ b/src/go/types/unify.go
@@ -782,7 +782,7 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
 				}
 				// If y is a defined type, it may not match against cx which
 				// is an underlying type (incl. int, string, etc.). Use assign
-				// mode here so that the unifier automatically takes under(y)
+				// mode here so that the unifier automatically uses y.Underlying()
 				// if necessary.
 				return u.nify(cx, yorig, assign, p)
 			}

From b5aefe07e5afe2fd5d49c6a4219cc826b3e4e34e Mon Sep 17 00:00:00 2001
From: Tobias Klauser 
Date: Tue, 14 Oct 2025 11:40:26 +0200
Subject: [PATCH 171/229] all: remove unnecessary loop variable copies in tests

Copying the loop variable is no longer necessary since Go 1.22.

Change-Id: Iebb21dac44a20ec200567f1d786f105a4ee4999d
Reviewed-on: https://go-review.googlesource.com/c/go/+/711640
Reviewed-by: Florian Lehner 
Auto-Submit: Damien Neil 
Reviewed-by: Dmitri Shuralyov 
Reviewed-by: Damien Neil 
Auto-Submit: Tobias Klauser 
LUCI-TryBot-Result: Go LUCI 
---
 src/archive/zip/reader_test.go                  | 2 --
 src/context/x_test.go                           | 1 -
 src/crypto/cipher/ctr_aes_test.go               | 6 ------
 src/crypto/rsa/rsa_test.go                      | 1 -
 src/crypto/tls/handshake_client_test.go         | 1 -
 src/crypto/tls/tls_test.go                      | 1 -
 src/crypto/x509/platform_test.go                | 1 -
 src/database/sql/sql_test.go                    | 1 -
 src/debug/buildinfo/buildinfo_test.go           | 3 ---
 src/debug/elf/file_test.go                      | 1 -
 src/encoding/binary/varint_test.go              | 1 -
 src/go/printer/printer_test.go                  | 1 -
 src/go/types/api_test.go                        | 2 --
 src/go/types/sizes_test.go                      | 1 -
 src/go/types/stdlib_test.go                     | 2 --
 src/internal/fuzz/encoding_test.go              | 2 --
 src/internal/fuzz/minimize_test.go              | 1 -
 src/internal/fuzz/worker_test.go                | 1 -
 src/internal/reflectlite/reflect_mirror_test.go | 1 -
 src/internal/trace/reader_test.go               | 1 -
 src/internal/trace/tracev1_test.go              | 1 -
 src/internal/zstd/fse_test.go                   | 1 -
 src/internal/zstd/zstd_test.go                  | 2 --
 src/log/syslog/syslog_test.go                   | 1 -
 src/math/rand/default_test.go                   | 1 -
 src/net/conn_test.go                            | 1 -
 src/net/dial_test.go                            | 1 -
 src/net/error_test.go                           | 1 -
 src/net/http/fs_test.go                         | 1 -
 src/net/http/httptest/recorder_test.go          | 1 -
 src/net/http/serve_test.go                      | 1 -
 src/net/http/transport_test.go                  | 1 -
 src/net/net_test.go                             | 6 ------
 src/net/server_test.go                          | 2 --
 src/net/timeout_test.go                         | 1 -
 src/net/unixsock_test.go                        | 2 --
 src/os/exec/exec_posix_test.go                  | 2 --
 src/os/signal/signal_test.go                    | 4 ----
 src/path/filepath/path_test.go                  | 1 -
 src/reflect/all_test.go                         | 3 ---
 src/reflect/visiblefields_test.go               | 1 -
 src/runtime/chan_test.go                        | 2 --
 src/runtime/checkptr_test.go                    | 2 --
 src/runtime/crash_cgo_test.go                   | 2 --
 src/runtime/map_benchmark_test.go               | 1 -
 src/runtime/memmove_test.go                     | 2 --
 src/runtime/mgcpacer_test.go                    | 1 -
 src/runtime/mgcscavenge_test.go                 | 3 ---
 src/runtime/mpagealloc_test.go                  | 5 -----
 src/runtime/mpagecache_test.go                  | 2 --
 src/runtime/mpallocbits_test.go                 | 4 ----
 src/runtime/proc_test.go                        | 1 -
 src/sync/atomic/value_test.go                   | 2 --
 src/syscall/exec_linux_test.go                  | 1 -
 src/testing/flag_test.go                        | 1 -
 src/testing/panic_test.go                       | 1 -
 src/testing/sub_test.go                         | 1 -
 src/time/sleep_test.go                          | 2 --
 58 files changed, 99 deletions(-)

diff --git a/src/archive/zip/reader_test.go b/src/archive/zip/reader_test.go
index 410b2d037e44d5..cb8a0c28714eff 100644
--- a/src/archive/zip/reader_test.go
+++ b/src/archive/zip/reader_test.go
@@ -1213,7 +1213,6 @@ func TestFS(t *testing.T) {
 			[]string{"a/b/c"},
 		},
 	} {
-		test := test
 		t.Run(test.file, func(t *testing.T) {
 			t.Parallel()
 			z, err := OpenReader(test.file)
@@ -1247,7 +1246,6 @@ func TestFSWalk(t *testing.T) {
 			wantErr: true,
 		},
 	} {
-		test := test
 		t.Run(test.file, func(t *testing.T) {
 			t.Parallel()
 			z, err := OpenReader(test.file)
diff --git a/src/context/x_test.go b/src/context/x_test.go
index 0cf19688c3f5ee..aeb5470399f4ee 100644
--- a/src/context/x_test.go
+++ b/src/context/x_test.go
@@ -838,7 +838,6 @@ func TestCause(t *testing.T) {
 			cause: parentCause,
 		},
 	} {
-		test := test
 		t.Run(test.name, func(t *testing.T) {
 			t.Parallel()
 			ctx := test.ctx()
diff --git a/src/crypto/cipher/ctr_aes_test.go b/src/crypto/cipher/ctr_aes_test.go
index 33942467784ad3..9b7d30e2164422 100644
--- a/src/crypto/cipher/ctr_aes_test.go
+++ b/src/crypto/cipher/ctr_aes_test.go
@@ -145,7 +145,6 @@ func TestCTR_AES_multiblock_random_IV(t *testing.T) {
 	const Size = 100
 
 	for _, keySize := range []int{16, 24, 32} {
-		keySize := keySize
 		t.Run(fmt.Sprintf("keySize=%d", keySize), func(t *testing.T) {
 			key := randBytes(t, r, keySize)
 			aesBlock, err := aes.NewCipher(key)
@@ -164,10 +163,8 @@ func TestCTR_AES_multiblock_random_IV(t *testing.T) {
 			// individually using multiblock implementation to catch edge cases.
 
 			for part1 := 0; part1 <= Size; part1++ {
-				part1 := part1
 				t.Run(fmt.Sprintf("part1=%d", part1), func(t *testing.T) {
 					for part2 := 0; part2 <= Size-part1; part2++ {
-						part2 := part2
 						t.Run(fmt.Sprintf("part2=%d", part2), func(t *testing.T) {
 							_, multiblockCtr := makeTestingCiphers(aesBlock, iv)
 							multiblockCiphertext := make([]byte, len(plaintext))
@@ -216,7 +213,6 @@ func TestCTR_AES_multiblock_overflow_IV(t *testing.T) {
 	}
 
 	for _, keySize := range []int{16, 24, 32} {
-		keySize := keySize
 		t.Run(fmt.Sprintf("keySize=%d", keySize), func(t *testing.T) {
 			for _, iv := range ivs {
 				key := randBytes(t, r, keySize)
@@ -227,7 +223,6 @@ func TestCTR_AES_multiblock_overflow_IV(t *testing.T) {
 
 				t.Run(fmt.Sprintf("iv=%s", hex.EncodeToString(iv)), func(t *testing.T) {
 					for _, offset := range []int{0, 1, 16, 1024} {
-						offset := offset
 						t.Run(fmt.Sprintf("offset=%d", offset), func(t *testing.T) {
 							genericCtr, multiblockCtr := makeTestingCiphers(aesBlock, iv)
 
@@ -260,7 +255,6 @@ func TestCTR_AES_multiblock_XORKeyStreamAt(t *testing.T) {
 	plaintext := randBytes(t, r, Size)
 
 	for _, keySize := range []int{16, 24, 32} {
-		keySize := keySize
 		t.Run(fmt.Sprintf("keySize=%d", keySize), func(t *testing.T) {
 			key := randBytes(t, r, keySize)
 			iv := randBytes(t, r, aesBlockSize)
diff --git a/src/crypto/rsa/rsa_test.go b/src/crypto/rsa/rsa_test.go
index 0d5b6e08f0e223..b9e85bd8ff8f37 100644
--- a/src/crypto/rsa/rsa_test.go
+++ b/src/crypto/rsa/rsa_test.go
@@ -212,7 +212,6 @@ func TestEverything(t *testing.T) {
 		max = 2048
 	}
 	for size := min; size <= max; size++ {
-		size := size
 		t.Run(fmt.Sprintf("%d", size), func(t *testing.T) {
 			t.Parallel()
 			priv, err := GenerateKey(rand.Reader, size)
diff --git a/src/crypto/tls/handshake_client_test.go b/src/crypto/tls/handshake_client_test.go
index 9c94016f1339ac..6020c0f055c776 100644
--- a/src/crypto/tls/handshake_client_test.go
+++ b/src/crypto/tls/handshake_client_test.go
@@ -2693,7 +2693,6 @@ func TestTLS13OnlyClientHelloCipherSuite(t *testing.T) {
 		},
 	}
 	for _, tt := range tls13Tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			testTLS13OnlyClientHelloCipherSuite(t, tt.ciphers)
diff --git a/src/crypto/tls/tls_test.go b/src/crypto/tls/tls_test.go
index bfcc62ccfb8ba0..6539009df6242a 100644
--- a/src/crypto/tls/tls_test.go
+++ b/src/crypto/tls/tls_test.go
@@ -1880,7 +1880,6 @@ func testVerifyCertificates(t *testing.T, version uint16) {
 	rootCAs.AddCert(issuer)
 
 	for _, test := range tests {
-		test := test
 		t.Run(test.name, func(t *testing.T) {
 			t.Parallel()
 
diff --git a/src/crypto/x509/platform_test.go b/src/crypto/x509/platform_test.go
index b425e02f3bc144..44ceff43f454df 100644
--- a/src/crypto/x509/platform_test.go
+++ b/src/crypto/x509/platform_test.go
@@ -202,7 +202,6 @@ func TestPlatformVerifier(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 			parent := testRoot
diff --git a/src/database/sql/sql_test.go b/src/database/sql/sql_test.go
index f706610b87e85b..c3f228ef0ba104 100644
--- a/src/database/sql/sql_test.go
+++ b/src/database/sql/sql_test.go
@@ -2939,7 +2939,6 @@ func TestConnExpiresFreshOutOfPool(t *testing.T) {
 	db.SetMaxOpenConns(1)
 
 	for _, ec := range execCases {
-		ec := ec
 		name := fmt.Sprintf("expired=%t,badReset=%t", ec.expired, ec.badReset)
 		t.Run(name, func(t *testing.T) {
 			db.clearAllConns(t)
diff --git a/src/debug/buildinfo/buildinfo_test.go b/src/debug/buildinfo/buildinfo_test.go
index 1c22f1ccdb7577..ceab14e8bff622 100644
--- a/src/debug/buildinfo/buildinfo_test.go
+++ b/src/debug/buildinfo/buildinfo_test.go
@@ -238,16 +238,13 @@ func TestReadFile(t *testing.T) {
 	}
 
 	for _, p := range platforms {
-		p := p
 		t.Run(p.goos+"_"+p.goarch, func(t *testing.T) {
 			if p != runtimePlatform && !*flagAll {
 				t.Skipf("skipping platforms other than %s_%s because -all was not set", runtimePlatform.goos, runtimePlatform.goarch)
 			}
 			for _, mode := range buildModes {
-				mode := mode
 				t.Run(mode, func(t *testing.T) {
 					for _, tc := range cases {
-						tc := tc
 						t.Run(tc.name, func(t *testing.T) {
 							t.Parallel()
 							name := tc.build(t, p.goos, p.goarch, mode)
diff --git a/src/debug/elf/file_test.go b/src/debug/elf/file_test.go
index 0c1a7cf18aeb6e..b796cdb95b65c6 100644
--- a/src/debug/elf/file_test.go
+++ b/src/debug/elf/file_test.go
@@ -1040,7 +1040,6 @@ var relocationTests = []relocationTest{
 
 func TestDWARFRelocations(t *testing.T) {
 	for _, test := range relocationTests {
-		test := test
 		t.Run(test.file, func(t *testing.T) {
 			t.Parallel()
 			f, err := Open(test.file)
diff --git a/src/encoding/binary/varint_test.go b/src/encoding/binary/varint_test.go
index 5c3ea318c397bd..dbb615070bf448 100644
--- a/src/encoding/binary/varint_test.go
+++ b/src/encoding/binary/varint_test.go
@@ -181,7 +181,6 @@ func TestBufferTooBigWithOverflow(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			value, n := Uvarint(tt.in)
 			if g, w := n, tt.wantN; g != w {
diff --git a/src/go/printer/printer_test.go b/src/go/printer/printer_test.go
index 2a9c8be3003249..604b8e5aea3a22 100644
--- a/src/go/printer/printer_test.go
+++ b/src/go/printer/printer_test.go
@@ -548,7 +548,6 @@ func TestBaseIndent(t *testing.T) {
 	}
 
 	for indent := 0; indent < 4; indent++ {
-		indent := indent
 		t.Run(fmt.Sprint(indent), func(t *testing.T) {
 			t.Parallel()
 			var buf bytes.Buffer
diff --git a/src/go/types/api_test.go b/src/go/types/api_test.go
index 2798b9e0c4eb47..f31b9d30c58add 100644
--- a/src/go/types/api_test.go
+++ b/src/go/types/api_test.go
@@ -2432,7 +2432,6 @@ type K = Nested[string]
 		)
 		var wg sync.WaitGroup
 		for i := 0; i < 2; i++ {
-			i := i
 			wg.Add(1)
 			go func() {
 				defer wg.Done()
@@ -2613,7 +2612,6 @@ func fn() {
 	})
 
 	for _, test := range tests {
-		test := test
 		t.Run(test.name, func(t *testing.T) {
 			if got := len(idents[test.name]); got != 1 {
 				t.Fatalf("found %d identifiers named %s, want 1", got, test.name)
diff --git a/src/go/types/sizes_test.go b/src/go/types/sizes_test.go
index 157faf87d4c575..e0ca14e11b279a 100644
--- a/src/go/types/sizes_test.go
+++ b/src/go/types/sizes_test.go
@@ -187,7 +187,6 @@ func main() {
 func TestGCSizes(t *testing.T) {
 	types.DefPredeclaredTestFuncs()
 	for _, tc := range gcSizesTests {
-		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 			conf := types.Config{
diff --git a/src/go/types/stdlib_test.go b/src/go/types/stdlib_test.go
index eb838b2c88e470..e7ef39fd5b53b8 100644
--- a/src/go/types/stdlib_test.go
+++ b/src/go/types/stdlib_test.go
@@ -70,8 +70,6 @@ func TestStdlib(t *testing.T) {
 	var wg sync.WaitGroup
 
 	for dir := range dirFiles {
-		dir := dir
-
 		cpulimit <- struct{}{}
 		wg.Add(1)
 		go func() {
diff --git a/src/internal/fuzz/encoding_test.go b/src/internal/fuzz/encoding_test.go
index a46a3474038099..5f2af4476b8652 100644
--- a/src/internal/fuzz/encoding_test.go
+++ b/src/internal/fuzz/encoding_test.go
@@ -260,7 +260,6 @@ func BenchmarkMarshalCorpusFile(b *testing.B) {
 	}
 
 	for sz := 1; sz <= len(buf); sz <<= 1 {
-		sz := sz
 		b.Run(strconv.Itoa(sz), func(b *testing.B) {
 			for i := 0; i < b.N; i++ {
 				b.SetBytes(int64(sz))
@@ -280,7 +279,6 @@ func BenchmarkUnmarshalCorpusFile(b *testing.B) {
 	}
 
 	for sz := 1; sz <= len(buf); sz <<= 1 {
-		sz := sz
 		data := marshalCorpusFile(buf[:sz])
 		b.Run(strconv.Itoa(sz), func(b *testing.B) {
 			for i := 0; i < b.N; i++ {
diff --git a/src/internal/fuzz/minimize_test.go b/src/internal/fuzz/minimize_test.go
index e7e23e5a052cc4..79d986374f08a1 100644
--- a/src/internal/fuzz/minimize_test.go
+++ b/src/internal/fuzz/minimize_test.go
@@ -132,7 +132,6 @@ func TestMinimizeInput(t *testing.T) {
 	}
 
 	for _, tc := range cases {
-		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 			ws := &workerServer{
diff --git a/src/internal/fuzz/worker_test.go b/src/internal/fuzz/worker_test.go
index d0b21da7838643..9420248d2c0d60 100644
--- a/src/internal/fuzz/worker_test.go
+++ b/src/internal/fuzz/worker_test.go
@@ -182,7 +182,6 @@ func BenchmarkWorkerMinimize(b *testing.B) {
 	bytes := make([]byte, 1024)
 	ctx := context.Background()
 	for sz := 1; sz <= len(bytes); sz <<= 1 {
-		sz := sz
 		input := []any{bytes[:sz]}
 		encodedVals := marshalCorpusFile(input...)
 		mem = <-ws.memMu
diff --git a/src/internal/reflectlite/reflect_mirror_test.go b/src/internal/reflectlite/reflect_mirror_test.go
index 8d13641516341a..c5642d092d9982 100644
--- a/src/internal/reflectlite/reflect_mirror_test.go
+++ b/src/internal/reflectlite/reflect_mirror_test.go
@@ -101,7 +101,6 @@ func TestMirrorWithReflect(t *testing.T) {
 		{".", "reflectlite", rl},
 		{reflectDir, "reflect", r},
 	} {
-		tc := tc
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
diff --git a/src/internal/trace/reader_test.go b/src/internal/trace/reader_test.go
index 39ae77471e7f73..e0733b827dfd19 100644
--- a/src/internal/trace/reader_test.go
+++ b/src/internal/trace/reader_test.go
@@ -33,7 +33,6 @@ func TestReaderGolden(t *testing.T) {
 		t.Fatalf("failed to glob for tests: %v", err)
 	}
 	for _, testPath := range matches {
-		testPath := testPath
 		testName, err := filepath.Rel("./testdata", testPath)
 		if err != nil {
 			t.Fatalf("failed to relativize testdata path: %v", err)
diff --git a/src/internal/trace/tracev1_test.go b/src/internal/trace/tracev1_test.go
index 42a83718877e1f..355a6ff529f2ae 100644
--- a/src/internal/trace/tracev1_test.go
+++ b/src/internal/trace/tracev1_test.go
@@ -21,7 +21,6 @@ func TestTraceV1(t *testing.T) {
 	}
 	var testedUserRegions bool
 	for _, p := range traces {
-		p := p
 		testName, err := filepath.Rel("./internal/tracev1/testdata", p)
 		if err != nil {
 			t.Fatalf("failed to relativize testdata path: %s", err)
diff --git a/src/internal/zstd/fse_test.go b/src/internal/zstd/fse_test.go
index 6f106b65b77814..20365745a5402e 100644
--- a/src/internal/zstd/fse_test.go
+++ b/src/internal/zstd/fse_test.go
@@ -68,7 +68,6 @@ func TestPredefinedTables(t *testing.T) {
 		},
 	}
 	for _, test := range tests {
-		test := test
 		t.Run(test.name, func(t *testing.T) {
 			var r Reader
 			table := make([]fseEntry, 1<= N {
 					b.Logf("bad") // just to capture b
diff --git a/src/sync/atomic/value_test.go b/src/sync/atomic/value_test.go
index 721da965e35800..b8bc8b8851b656 100644
--- a/src/sync/atomic/value_test.go
+++ b/src/sync/atomic/value_test.go
@@ -185,7 +185,6 @@ func TestValueSwapConcurrent(t *testing.T) {
 		n = 1000
 	}
 	for i := uint64(0); i < m*n; i += n {
-		i := i
 		g.Add(1)
 		go func() {
 			var c uint64
@@ -256,7 +255,6 @@ func TestValueCompareAndSwapConcurrent(t *testing.T) {
 		n = 100
 	}
 	for i := 0; i < m; i++ {
-		i := i
 		w.Add(1)
 		go func() {
 			for j := i; j < m*n; runtime.Gosched() {
diff --git a/src/syscall/exec_linux_test.go b/src/syscall/exec_linux_test.go
index 69d49169446d1c..ac04e51b144cb3 100644
--- a/src/syscall/exec_linux_test.go
+++ b/src/syscall/exec_linux_test.go
@@ -51,7 +51,6 @@ func whoamiNEWUSER(t *testing.T, uid, gid int, setgroups bool) *exec.Cmd {
 
 func TestCloneNEWUSERAndRemap(t *testing.T) {
 	for _, setgroups := range []bool{false, true} {
-		setgroups := setgroups
 		t.Run(fmt.Sprintf("setgroups=%v", setgroups), func(t *testing.T) {
 			uid := os.Getuid()
 			gid := os.Getgid()
diff --git a/src/testing/flag_test.go b/src/testing/flag_test.go
index 6a7754425d5bb8..fb65e1592811e3 100644
--- a/src/testing/flag_test.go
+++ b/src/testing/flag_test.go
@@ -25,7 +25,6 @@ func TestFlag(t *testing.T) {
 	testenv.MustHaveExec(t)
 
 	for _, flag := range []string{"", "-test.v", "-test.v=test2json"} {
-		flag := flag
 		t.Run(flag, func(t *testing.T) {
 			t.Parallel()
 			cmd := exec.Command(testenv.Executable(t), "-test.run=^TestFlag$", "-test_flag_arg="+flag)
diff --git a/src/testing/panic_test.go b/src/testing/panic_test.go
index fc84175ee6f0dd..01a34b08019edd 100644
--- a/src/testing/panic_test.go
+++ b/src/testing/panic_test.go
@@ -198,7 +198,6 @@ func TestPanicHelper(t *testing.T) {
 		}
 	})
 	for i := 0; i < 3; i++ {
-		i := i
 		t.Run(fmt.Sprintf("%v", i), func(t *testing.T) {
 			chosen := t.Name() == *testPanicTest
 			if chosen && *testPanicCleanup {
diff --git a/src/testing/sub_test.go b/src/testing/sub_test.go
index bb5586d9fcb526..5d5573ccec506b 100644
--- a/src/testing/sub_test.go
+++ b/src/testing/sub_test.go
@@ -988,7 +988,6 @@ func TestConcurrentCleanup(t *T) {
 		var wg sync.WaitGroup
 		wg.Add(2)
 		for i := 0; i < 2; i++ {
-			i := i
 			go func() {
 				t.Cleanup(func() {
 					// Although the calls to Cleanup are concurrent, the functions passed
diff --git a/src/time/sleep_test.go b/src/time/sleep_test.go
index b9e81b98febef2..c87f420f8f360e 100644
--- a/src/time/sleep_test.go
+++ b/src/time/sleep_test.go
@@ -937,7 +937,6 @@ func BenchmarkParallelTimerLatency(b *testing.B) {
 		wg.Add(timerCount)
 		atomic.StoreInt32(&count, 0)
 		for j := 0; j < timerCount; j++ {
-			j := j
 			expectedWakeup := Now().Add(delay)
 			AfterFunc(delay, func() {
 				late := Since(expectedWakeup)
@@ -1011,7 +1010,6 @@ func BenchmarkStaggeredTickerLatency(b *testing.B) {
 					var wg sync.WaitGroup
 					wg.Add(tickerCount)
 					for j := 0; j < tickerCount; j++ {
-						j := j
 						doWork(delay / Duration(gmp))
 						expectedWakeup := Now().Add(delay)
 						ticker := NewTicker(delay)

From 80876f4b42c807e0f90eab20a3e8a98ef95f2cb0 Mon Sep 17 00:00:00 2001
From: Alan Donovan 
Date: Fri, 17 Oct 2025 16:11:56 -0400
Subject: [PATCH 172/229] cmd/go/internal/vet: tweak help doc

For #71859

Change-Id: I3cea3375bd5adff9486b849e472d29ad8324dd54
Reviewed-on: https://go-review.googlesource.com/c/go/+/712665
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Alan Donovan 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/alldocs.go          | 19 ++++++++++---------
 src/cmd/go/internal/vet/vet.go | 19 ++++++++++---------
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 67c0ecbe8b2fcf..46bca7480b70a4 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -501,7 +501,7 @@
 //
 //	go fix [build flags] [-fixtool prog] [fix flags] [packages]
 //
-// Fix runs the Go fix tool (cmd/vet) on the named packages
+// Fix runs the Go fix tool (cmd/fix) on the named packages
 // and applies suggested fixes.
 //
 // It supports these flags:
@@ -510,15 +510,14 @@
 //		instead of applying each fix, print the patch as a unified diff
 //
 // The -fixtool=prog flag selects a different analysis tool with
-// alternative or additional fixes; see the documentation for go vet's
+// alternative or additional fixers; see the documentation for go vet's
 // -vettool flag for details.
 //
-// For more about specifying packages, see 'go help packages'.
-//
-// For a list of fixers and their flags, see 'go tool fix help'.
+// The default fix tool is 'go tool fix' or cmd/fix.
+// For help on its fixers and their flags, run 'go tool fix help'.
+// For details of a specific fixer such as 'hostport', see 'go tool fix help hostport'.
 //
-// For details of a specific fixer such as 'hostport',
-// see 'go tool fix help hostport'.
+// For more about specifying packages, see 'go help packages'.
 //
 // The build flags supported by go fix are those that control package resolution
 // and execution, such as -C, -n, -x, -v, -tags, and -toolexec.
@@ -2050,10 +2049,12 @@
 // Alternative vet tools should be built atop golang.org/x/tools/go/analysis/unitchecker,
 // which handles the interaction with go vet.
 //
-// For more about specifying packages, see 'go help packages'.
-// For a list of checkers and their flags, see 'go tool vet help'.
+// The default vet tool is 'go tool vet' or cmd/vet.
+// For help on its checkers and their flags, run 'go tool vet help'.
 // For details of a specific checker such as 'printf', see 'go tool vet help printf'.
 //
+// For more about specifying packages, see 'go help packages'.
+//
 // The build flags supported by go vet are those that control package resolution
 // and execution, such as -C, -n, -x, -v, -tags, and -toolexec.
 // For more about these flags, see 'go help build'.
diff --git a/src/cmd/go/internal/vet/vet.go b/src/cmd/go/internal/vet/vet.go
index f9579d498f573a..7c79dccd539aa0 100644
--- a/src/cmd/go/internal/vet/vet.go
+++ b/src/cmd/go/internal/vet/vet.go
@@ -54,10 +54,12 @@ can be built and run using these commands:
 Alternative vet tools should be built atop golang.org/x/tools/go/analysis/unitchecker,
 which handles the interaction with go vet.
 
-For more about specifying packages, see 'go help packages'.
-For a list of checkers and their flags, see 'go tool vet help'.
+The default vet tool is 'go tool vet' or cmd/vet.
+For help on its checkers and their flags, run 'go tool vet help'.
 For details of a specific checker such as 'printf', see 'go tool vet help printf'.
 
+For more about specifying packages, see 'go help packages'.
+
 The build flags supported by go vet are those that control package resolution
 and execution, such as -C, -n, -x, -v, -tags, and -toolexec.
 For more about these flags, see 'go help build'.
@@ -71,7 +73,7 @@ var CmdFix = &base.Command{
 	UsageLine:   "go fix [build flags] [-fixtool prog] [fix flags] [packages]",
 	Short:       "apply fixes suggested by static checkers",
 	Long: `
-Fix runs the Go fix tool (cmd/vet) on the named packages
+Fix runs the Go fix tool (cmd/fix) on the named packages
 and applies suggested fixes.
 
 It supports these flags:
@@ -80,15 +82,14 @@ It supports these flags:
 	instead of applying each fix, print the patch as a unified diff
 
 The -fixtool=prog flag selects a different analysis tool with
-alternative or additional fixes; see the documentation for go vet's
+alternative or additional fixers; see the documentation for go vet's
 -vettool flag for details.
 
-For more about specifying packages, see 'go help packages'.
-
-For a list of fixers and their flags, see 'go tool fix help'.
+The default fix tool is 'go tool fix' or cmd/fix.
+For help on its fixers and their flags, run 'go tool fix help'.
+For details of a specific fixer such as 'hostport', see 'go tool fix help hostport'.
 
-For details of a specific fixer such as 'hostport',
-see 'go tool fix help hostport'.
+For more about specifying packages, see 'go help packages'.
 
 The build flags supported by go fix are those that control package resolution
 and execution, such as -C, -n, -x, -v, -tags, and -toolexec.

From a5f55a441ef497d8e2a12610f4ec2bd32fdc04b2 Mon Sep 17 00:00:00 2001
From: Alan Donovan 
Date: Fri, 10 Oct 2025 15:49:53 -0400
Subject: [PATCH 173/229] cmd/fix: add modernize and inline analyzers

We ran 'go mod vendor' to pull in the newly used packages.

Also, add a cmd/go script test that minimally
exercises each analyzer, analogous to the cmd/vet test.

For #75266
For #75267
For #71859

Change-Id: I334daea048e3d2f614a1788292a3175acf173932
Reviewed-on: https://go-review.googlesource.com/c/go/+/710995
Reviewed-by: Michael Matloob 
Auto-Submit: Alan Donovan 
TryBot-Bypass: Alan Donovan 
Reviewed-by: Michael Matloob 
---
 src/cmd/fix/main.go                           |   28 +-
 src/cmd/go/testdata/script/fix_suite.txt      |   53 +
 .../x/tools/go/analysis/passes/inline/doc.go  |  109 +
 .../tools/go/analysis/passes/inline/gofix.go  |  537 +++
 .../internal/gofixdirective/gofixdirective.go |  143 +
 .../tools/go/analysis/passes/modernize/any.go |   61 +
 .../go/analysis/passes/modernize/bloop.go     |  250 ++
 .../tools/go/analysis/passes/modernize/doc.go |  455 ++
 .../analysis/passes/modernize/errorsastype.go |  243 ++
 .../analysis/passes/modernize/fmtappendf.go   |  115 +
 .../go/analysis/passes/modernize/forvar.go    |   94 +
 .../go/analysis/passes/modernize/maps.go      |  280 ++
 .../go/analysis/passes/modernize/minmax.go    |  440 ++
 .../go/analysis/passes/modernize/modernize.go |  162 +
 .../go/analysis/passes/modernize/newexpr.go   |  208 +
 .../go/analysis/passes/modernize/omitzero.go  |  119 +
 .../go/analysis/passes/modernize/plusbuild.go |   83 +
 .../go/analysis/passes/modernize/rangeint.go  |  310 ++
 .../go/analysis/passes/modernize/reflect.go   |  143 +
 .../go/analysis/passes/modernize/slices.go    |  300 ++
 .../passes/modernize/slicescontains.go        |  433 ++
 .../analysis/passes/modernize/slicesdelete.go |  184 +
 .../go/analysis/passes/modernize/sortslice.go |  124 +
 .../analysis/passes/modernize/stditerators.go |  354 ++
 .../passes/modernize/stringsbuilder.go        |  328 ++
 .../passes/modernize/stringscutprefix.go      |  261 ++
 .../analysis/passes/modernize/stringsseq.go   |  145 +
 .../passes/modernize/testingcontext.go        |  253 ++
 .../go/analysis/passes/modernize/waitgroup.go |  175 +
 .../x/tools/go/ast/astutil/enclosing.go       |  663 +++
 .../x/tools/go/ast/astutil/imports.go         |  472 +++
 .../x/tools/go/ast/astutil/rewrite.go         |  490 +++
 .../golang.org/x/tools/go/ast/astutil/util.go |   13 +
 .../analysisinternal/generated/generated.go   |   41 +
 .../x/tools/internal/goplsexport/export.go    |   15 +
 .../tools/internal/refactor/inline/callee.go  |  867 ++++
 .../internal/refactor/inline/calleefx.go      |  349 ++
 .../x/tools/internal/refactor/inline/doc.go   |  288 ++
 .../tools/internal/refactor/inline/escape.go  |  102 +
 .../tools/internal/refactor/inline/falcon.go  |  879 ++++
 .../x/tools/internal/refactor/inline/free.go  |  382 ++
 .../tools/internal/refactor/inline/inline.go  | 3744 +++++++++++++++++
 .../x/tools/internal/refactor/inline/util.go  |  168 +
 src/cmd/vendor/modules.txt                    |    7 +
 src/cmd/vet/vet_test.go                       |    4 +
 45 files changed, 14862 insertions(+), 12 deletions(-)
 create mode 100644 src/cmd/go/testdata/script/fix_suite.txt
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/inline/doc.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/inline/gofix.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/internal/gofixdirective/gofixdirective.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/any.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/bloop.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/doc.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/errorsastype.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/fmtappendf.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/forvar.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/maps.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/minmax.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/modernize.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/newexpr.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/omitzero.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/plusbuild.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/rangeint.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/reflect.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slices.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slicescontains.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slicesdelete.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/sortslice.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stditerators.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringsbuilder.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringscutprefix.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringsseq.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/testingcontext.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/waitgroup.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/ast/astutil/enclosing.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/ast/astutil/imports.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/ast/astutil/rewrite.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/go/ast/astutil/util.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/generated/generated.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/goplsexport/export.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/callee.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/calleefx.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/doc.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/escape.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/falcon.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/free.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/inline.go
 create mode 100644 src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/util.go

diff --git a/src/cmd/fix/main.go b/src/cmd/fix/main.go
index 422fa827459900..8fc412fe29e02c 100644
--- a/src/cmd/fix/main.go
+++ b/src/cmd/fix/main.go
@@ -22,10 +22,13 @@ package main
 import (
 	"cmd/internal/objabi"
 	"cmd/internal/telemetry/counter"
+	"slices"
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/buildtag"
 	"golang.org/x/tools/go/analysis/passes/hostport"
+	"golang.org/x/tools/go/analysis/passes/inline"
+	"golang.org/x/tools/go/analysis/passes/modernize"
 	"golang.org/x/tools/go/analysis/unitchecker"
 )
 
@@ -38,22 +41,23 @@ func main() {
 	unitchecker.Main(suite...) // (never returns)
 }
 
-// The fix suite analyzers produce fixes that are safe to apply.
-// (Diagnostics may not describe actual problems,
-// but their fixes must be unambiguously safe to apply.)
-var suite = []*analysis.Analyzer{
-	buildtag.Analyzer,
-	hostport.Analyzer,
-	// TODO(adonovan): now the modernize (proposal #75266) and
-	// inline (proposal #75267) analyzers are published, revendor
-	// x/tools and add them here.
-	//
-	// TODO(adonovan):add any other vet analyzers whose fixes are always safe.
+// The fix suite analyzers produce fixes are unambiguously safe to apply,
+// even if the diagnostics might not describe actual problems.
+var suite = slices.Concat(
+	[]*analysis.Analyzer{
+		buildtag.Analyzer,
+		hostport.Analyzer,
+		inline.Analyzer,
+	},
+	modernize.Suite,
+	// TODO(adonovan): add any other vet analyzers whose fixes are always safe.
 	// Candidates to audit: sigchanyzer, printf, assign, unreachable.
+	// Many of staticcheck's analyzers would make good candidates
+	//   (e.g. rewriting WriteString(fmt.Sprintf()) to Fprintf.)
 	// Rejected:
 	// - composites: some types (e.g. PointXY{1,2}) don't want field names.
 	// - timeformat: flipping MM/DD is a behavior change, but the code
 	//    could potentially be a workaround for another bug.
 	// - stringintconv: offers two fixes, user input required to choose.
 	// - fieldalignment: poor signal/noise; fix could be a regression.
-}
+)
diff --git a/src/cmd/go/testdata/script/fix_suite.txt b/src/cmd/go/testdata/script/fix_suite.txt
new file mode 100644
index 00000000000000..455629dc172f30
--- /dev/null
+++ b/src/cmd/go/testdata/script/fix_suite.txt
@@ -0,0 +1,53 @@
+# Elementary test of each analyzer in the "go fix" suite.
+# This is simply to prove that they are running at all;
+# detailed behavior is tested in x/tools.
+#
+# Each assertion matches the expected diff.
+#
+# Tip: to see the actual stdout,
+# temporarily prefix the go command with "! ".
+
+go fix -diff example.com/x
+
+# buildtag
+stdout '-// \+build go1.26'
+
+# hostport
+stdout 'net.Dial.*net.JoinHostPort'
+
+# inline
+stdout 'var three = 1 \+ 2'
+
+# newexpr (proxy for whole modernize suite)
+stdout 'var _ = new\(123\)'
+
+-- go.mod --
+module example.com/x
+go 1.26
+
+-- x.go --
+//go:build go1.26
+// +build go1.26
+
+// ↑ buildtag
+
+package x
+
+import (
+	"fmt"
+	"net"
+)
+
+// hostport
+var s string
+var _, _ = net.Dial("tcp", fmt.Sprintf("%s:%d", s, 80))
+
+//go:fix inline
+func add(x, y int) int { return x + y }
+
+// inline
+var three = add(1, 2)
+
+// newexpr
+func varOf(x int) *int { return &x }
+var _ = varOf(123)
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/inline/doc.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/inline/doc.go
new file mode 100644
index 00000000000000..a3e98cb6572c7c
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/inline/doc.go
@@ -0,0 +1,109 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package inline defines an analyzer that inlines calls to functions
+and uses of constants marked with a "//go:fix inline" directive.
+
+# Analyzer inline
+
+inline: apply fixes based on 'go:fix inline' comment directives
+
+The inline analyzer inlines functions and constants that are marked for inlining.
+
+## Functions
+
+Given a function that is marked for inlining, like this one:
+
+	//go:fix inline
+	func Square(x int) int { return Pow(x, 2) }
+
+this analyzer will recommend that calls to the function elsewhere, in the same
+or other packages, should be inlined.
+
+Inlining can be used to move off of a deprecated function:
+
+	// Deprecated: prefer Pow(x, 2).
+	//go:fix inline
+	func Square(x int) int { return Pow(x, 2) }
+
+It can also be used to move off of an obsolete package,
+as when the import path has changed or a higher major version is available:
+
+	package pkg
+
+	import pkg2 "pkg/v2"
+
+	//go:fix inline
+	func F() { pkg2.F(nil) }
+
+Replacing a call pkg.F() by pkg2.F(nil) can have no effect on the program,
+so this mechanism provides a low-risk way to update large numbers of calls.
+We recommend, where possible, expressing the old API in terms of the new one
+to enable automatic migration.
+
+The inliner takes care to avoid behavior changes, even subtle ones,
+such as changes to the order in which argument expressions are
+evaluated. When it cannot safely eliminate all parameter variables,
+it may introduce a "binding declaration" of the form
+
+	var params = args
+
+to evaluate argument expressions in the correct order and bind them to
+parameter variables. Since the resulting code transformation may be
+stylistically suboptimal, such inlinings may be disabled by specifying
+the -inline.allow_binding_decl=false flag to the analyzer driver.
+
+(In cases where it is not safe to "reduce" a call—that is, to replace
+a call f(x) by the body of function f, suitably substituted—the
+inliner machinery is capable of replacing f by a function literal,
+func(){...}(). However, the inline analyzer discards all such
+"literalizations" unconditionally, again on grounds of style.)
+
+## Constants
+
+Given a constant that is marked for inlining, like this one:
+
+	//go:fix inline
+	const Ptr = Pointer
+
+this analyzer will recommend that uses of Ptr should be replaced with Pointer.
+
+As with functions, inlining can be used to replace deprecated constants and
+constants in obsolete packages.
+
+A constant definition can be marked for inlining only if it refers to another
+named constant.
+
+The "//go:fix inline" comment must appear before a single const declaration on its own,
+as above; before a const declaration that is part of a group, as in this case:
+
+	const (
+	   C = 1
+	   //go:fix inline
+	   Ptr = Pointer
+	)
+
+or before a group, applying to every constant in the group:
+
+	//go:fix inline
+	const (
+		Ptr = Pointer
+	    Val = Value
+	)
+
+The proposal https://go.dev/issue/32816 introduces the "//go:fix inline" directives.
+
+You can use this command to apply inline fixes en masse:
+
+	$ go run golang.org/x/tools/go/analysis/passes/inline/cmd/inline@latest -fix ./...
+
+# Analyzer gofixdirective
+
+gofixdirective: validate uses of //go:fix comment directives
+
+The gofixdirective analyzer checks "//go:fix inline" directives for correctness.
+See the documentation for the gofix analyzer for more about "/go:fix inline".
+*/
+package inline
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/inline/gofix.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/inline/gofix.go
new file mode 100644
index 00000000000000..629d5d8526f6c9
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/inline/gofix.go
@@ -0,0 +1,537 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package inline
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"slices"
+	"strings"
+
+	_ "embed"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/analysis/passes/internal/gofixdirective"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/diff"
+	"golang.org/x/tools/internal/packagepath"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/refactor/inline"
+	"golang.org/x/tools/internal/typesinternal"
+)
+
+//go:embed doc.go
+var doc string
+
+var Analyzer = &analysis.Analyzer{
+	Name: "inline",
+	Doc:  analysisinternal.MustExtractDoc(doc, "inline"),
+	URL:  "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/inline",
+	Run:  run,
+	FactTypes: []analysis.Fact{
+		(*goFixInlineFuncFact)(nil),
+		(*goFixInlineConstFact)(nil),
+		(*goFixInlineAliasFact)(nil),
+	},
+	Requires: []*analysis.Analyzer{inspect.Analyzer},
+}
+
+var allowBindingDecl bool
+
+func init() {
+	Analyzer.Flags.BoolVar(&allowBindingDecl, "allow_binding_decl", false,
+		"permit inlinings that require a 'var params = args' declaration")
+}
+
+// analyzer holds the state for this analysis.
+type analyzer struct {
+	pass *analysis.Pass
+	root inspector.Cursor
+	// memoization of repeated calls for same file.
+	fileContent map[string][]byte
+	// memoization of fact imports (nil => no fact)
+	inlinableFuncs   map[*types.Func]*inline.Callee
+	inlinableConsts  map[*types.Const]*goFixInlineConstFact
+	inlinableAliases map[*types.TypeName]*goFixInlineAliasFact
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	a := &analyzer{
+		pass:             pass,
+		root:             pass.ResultOf[inspect.Analyzer].(*inspector.Inspector).Root(),
+		fileContent:      make(map[string][]byte),
+		inlinableFuncs:   make(map[*types.Func]*inline.Callee),
+		inlinableConsts:  make(map[*types.Const]*goFixInlineConstFact),
+		inlinableAliases: make(map[*types.TypeName]*goFixInlineAliasFact),
+	}
+	gofixdirective.Find(pass, a.root, a)
+	a.inline()
+	return nil, nil
+}
+
+// HandleFunc exports a fact for functions marked with go:fix.
+func (a *analyzer) HandleFunc(decl *ast.FuncDecl) {
+	content, err := a.readFile(decl)
+	if err != nil {
+		a.pass.Reportf(decl.Doc.Pos(), "invalid inlining candidate: cannot read source file: %v", err)
+		return
+	}
+	callee, err := inline.AnalyzeCallee(discard, a.pass.Fset, a.pass.Pkg, a.pass.TypesInfo, decl, content)
+	if err != nil {
+		a.pass.Reportf(decl.Doc.Pos(), "invalid inlining candidate: %v", err)
+		return
+	}
+	fn := a.pass.TypesInfo.Defs[decl.Name].(*types.Func)
+	a.pass.ExportObjectFact(fn, &goFixInlineFuncFact{callee})
+	a.inlinableFuncs[fn] = callee
+}
+
+// HandleAlias exports a fact for aliases marked with go:fix.
+func (a *analyzer) HandleAlias(spec *ast.TypeSpec) {
+	// Remember that this is an inlinable alias.
+	typ := &goFixInlineAliasFact{}
+	lhs := a.pass.TypesInfo.Defs[spec.Name].(*types.TypeName)
+	a.inlinableAliases[lhs] = typ
+	// Create a fact only if the LHS is exported and defined at top level.
+	// We create a fact even if the RHS is non-exported,
+	// so we can warn about uses in other packages.
+	if lhs.Exported() && typesinternal.IsPackageLevel(lhs) {
+		a.pass.ExportObjectFact(lhs, typ)
+	}
+}
+
+// HandleConst exports a fact for constants marked with go:fix.
+func (a *analyzer) HandleConst(nameIdent, rhsIdent *ast.Ident) {
+	lhs := a.pass.TypesInfo.Defs[nameIdent].(*types.Const)
+	rhs := a.pass.TypesInfo.Uses[rhsIdent].(*types.Const) // must be so in a well-typed program
+	con := &goFixInlineConstFact{
+		RHSName:    rhs.Name(),
+		RHSPkgName: rhs.Pkg().Name(),
+		RHSPkgPath: rhs.Pkg().Path(),
+	}
+	if rhs.Pkg() == a.pass.Pkg {
+		con.rhsObj = rhs
+	}
+	a.inlinableConsts[lhs] = con
+	// Create a fact only if the LHS is exported and defined at top level.
+	// We create a fact even if the RHS is non-exported,
+	// so we can warn about uses in other packages.
+	if lhs.Exported() && typesinternal.IsPackageLevel(lhs) {
+		a.pass.ExportObjectFact(lhs, con)
+	}
+}
+
+// inline inlines each static call to an inlinable function
+// and each reference to an inlinable constant or type alias.
+//
+// TODO(adonovan):  handle multiple diffs that each add the same import.
+func (a *analyzer) inline() {
+	for cur := range a.root.Preorder((*ast.CallExpr)(nil), (*ast.Ident)(nil)) {
+		switch n := cur.Node().(type) {
+		case *ast.CallExpr:
+			a.inlineCall(n, cur)
+
+		case *ast.Ident:
+			switch t := a.pass.TypesInfo.Uses[n].(type) {
+			case *types.TypeName:
+				a.inlineAlias(t, cur)
+			case *types.Const:
+				a.inlineConst(t, cur)
+			}
+		}
+	}
+}
+
+// If call is a call to an inlinable func, suggest inlining its use at cur.
+func (a *analyzer) inlineCall(call *ast.CallExpr, cur inspector.Cursor) {
+	if fn := typeutil.StaticCallee(a.pass.TypesInfo, call); fn != nil {
+		// Inlinable?
+		callee, ok := a.inlinableFuncs[fn]
+		if !ok {
+			var fact goFixInlineFuncFact
+			if a.pass.ImportObjectFact(fn, &fact) {
+				callee = fact.Callee
+				a.inlinableFuncs[fn] = callee
+			}
+		}
+		if callee == nil {
+			return // nope
+		}
+
+		// Inline the call.
+		content, err := a.readFile(call)
+		if err != nil {
+			a.pass.Reportf(call.Lparen, "invalid inlining candidate: cannot read source file: %v", err)
+			return
+		}
+		curFile := astutil.EnclosingFile(cur)
+		caller := &inline.Caller{
+			Fset:    a.pass.Fset,
+			Types:   a.pass.Pkg,
+			Info:    a.pass.TypesInfo,
+			File:    curFile,
+			Call:    call,
+			Content: content,
+		}
+		res, err := inline.Inline(caller, callee, &inline.Options{Logf: discard})
+		if err != nil {
+			a.pass.Reportf(call.Lparen, "%v", err)
+			return
+		}
+
+		if res.Literalized {
+			// Users are not fond of inlinings that literalize
+			// f(x) to func() { ... }(), so avoid them.
+			//
+			// (Unfortunately the inliner is very timid,
+			// and often literalizes when it cannot prove that
+			// reducing the call is safe; the user of this tool
+			// has no indication of what the problem is.)
+			return
+		}
+		if res.BindingDecl && !allowBindingDecl {
+			// When applying fix en masse, users are similarly
+			// unenthusiastic about inlinings that cannot
+			// entirely eliminate the parameters and
+			// insert a 'var params = args' declaration.
+			// The flag allows them to decline such fixes.
+			return
+		}
+		got := res.Content
+
+		// Suggest the "fix".
+		var textEdits []analysis.TextEdit
+		for _, edit := range diff.Bytes(content, got) {
+			textEdits = append(textEdits, analysis.TextEdit{
+				Pos:     curFile.FileStart + token.Pos(edit.Start),
+				End:     curFile.FileStart + token.Pos(edit.End),
+				NewText: []byte(edit.New),
+			})
+		}
+		a.pass.Report(analysis.Diagnostic{
+			Pos:     call.Pos(),
+			End:     call.End(),
+			Message: fmt.Sprintf("Call of %v should be inlined", callee),
+			SuggestedFixes: []analysis.SuggestedFix{{
+				Message:   fmt.Sprintf("Inline call of %v", callee),
+				TextEdits: textEdits,
+			}},
+		})
+	}
+}
+
+// If tn is the TypeName of an inlinable alias, suggest inlining its use at cur.
+func (a *analyzer) inlineAlias(tn *types.TypeName, curId inspector.Cursor) {
+	inalias, ok := a.inlinableAliases[tn]
+	if !ok {
+		var fact goFixInlineAliasFact
+		if a.pass.ImportObjectFact(tn, &fact) {
+			inalias = &fact
+			a.inlinableAliases[tn] = inalias
+		}
+	}
+	if inalias == nil {
+		return // nope
+	}
+
+	alias := tn.Type().(*types.Alias)
+	// Remember the names of the alias's type params. When we check for shadowing
+	// later, we'll ignore these because they won't appear in the replacement text.
+	typeParamNames := map[*types.TypeName]bool{}
+	for tp := range alias.TypeParams().TypeParams() {
+		typeParamNames[tp.Obj()] = true
+	}
+	rhs := alias.Rhs()
+	curPath := a.pass.Pkg.Path()
+	curFile := astutil.EnclosingFile(curId)
+	id := curId.Node().(*ast.Ident)
+	// We have an identifier A here (n), possibly qualified by a package
+	// identifier (sel.n), and an inlinable "type A = rhs" elsewhere.
+	//
+	// We can replace A with rhs if no name in rhs is shadowed at n's position,
+	// and every package in rhs is importable by the current package.
+
+	var (
+		importPrefixes = map[string]string{curPath: ""} // from pkg path to prefix
+		edits          []analysis.TextEdit
+	)
+	for _, tn := range typenames(rhs) {
+		// Ignore the type parameters of the alias: they won't appear in the result.
+		if typeParamNames[tn] {
+			continue
+		}
+		var pkgPath, pkgName string
+		if pkg := tn.Pkg(); pkg != nil {
+			pkgPath = pkg.Path()
+			pkgName = pkg.Name()
+		}
+		if pkgPath == "" || pkgPath == curPath {
+			// The name is in the current package or the universe scope, so no import
+			// is required. Check that it is not shadowed (that is, that the type
+			// it refers to in rhs is the same one it refers to at n).
+			scope := a.pass.TypesInfo.Scopes[curFile].Innermost(id.Pos()) // n's scope
+			_, obj := scope.LookupParent(tn.Name(), id.Pos())             // what qn.name means in n's scope
+			if obj != tn {
+				return
+			}
+		} else if !packagepath.CanImport(a.pass.Pkg.Path(), pkgPath) {
+			// If this package can't see the package of this part of rhs, we can't inline.
+			return
+		} else if _, ok := importPrefixes[pkgPath]; !ok {
+			// Use AddImport to add pkgPath if it's not there already. Associate the prefix it assigns
+			// with the package path for use by the TypeString qualifier below.
+			prefix, eds := refactor.AddImport(
+				a.pass.TypesInfo, curFile, pkgName, pkgPath, tn.Name(), id.Pos())
+			importPrefixes[pkgPath] = strings.TrimSuffix(prefix, ".")
+			edits = append(edits, eds...)
+		}
+	}
+	// Find the complete identifier, which may take any of these forms:
+	//       Id
+	//       Id[T]
+	//       Id[K, V]
+	//   pkg.Id
+	//   pkg.Id[T]
+	//   pkg.Id[K, V]
+	var expr ast.Expr = id
+	if astutil.IsChildOf(curId, edge.SelectorExpr_Sel) {
+		curId = curId.Parent()
+		expr = curId.Node().(ast.Expr)
+	}
+	// If expr is part of an IndexExpr or IndexListExpr, we'll need that node.
+	// Given C[int], TypeOf(C) is generic but TypeOf(C[int]) is instantiated.
+	switch ek, _ := curId.ParentEdge(); ek {
+	case edge.IndexExpr_X:
+		expr = curId.Parent().Node().(*ast.IndexExpr)
+	case edge.IndexListExpr_X:
+		expr = curId.Parent().Node().(*ast.IndexListExpr)
+	}
+	t := a.pass.TypesInfo.TypeOf(expr).(*types.Alias) // type of entire identifier
+	if targs := t.TypeArgs(); targs.Len() > 0 {
+		// Instantiate the alias with the type args from this use.
+		// For example, given type A = M[K, V], compute the type of the use
+		// A[int, Foo] as M[int, Foo].
+		// Don't validate instantiation: it can't panic unless we have a bug,
+		// in which case seeing the stack trace via telemetry would be helpful.
+		instAlias, _ := types.Instantiate(nil, alias, slices.Collect(targs.Types()), false)
+		rhs = instAlias.(*types.Alias).Rhs()
+	}
+	// To get the replacement text, render the alias RHS using the package prefixes
+	// we assigned above.
+	newText := types.TypeString(rhs, func(p *types.Package) string {
+		if p == a.pass.Pkg {
+			return ""
+		}
+		if prefix, ok := importPrefixes[p.Path()]; ok {
+			return prefix
+		}
+		panic(fmt.Sprintf("in %q, package path %q has no import prefix", rhs, p.Path()))
+	})
+	a.reportInline("type alias", "Type alias", expr, edits, newText)
+}
+
+// typenames returns the TypeNames for types within t (including t itself) that have
+// them: basic types, named types and alias types.
+// The same name may appear more than once.
+func typenames(t types.Type) []*types.TypeName {
+	var tns []*types.TypeName
+
+	var visit func(types.Type)
+	visit = func(t types.Type) {
+		if hasName, ok := t.(interface{ Obj() *types.TypeName }); ok {
+			tns = append(tns, hasName.Obj())
+		}
+		switch t := t.(type) {
+		case *types.Basic:
+			tns = append(tns, types.Universe.Lookup(t.Name()).(*types.TypeName))
+		case *types.Named:
+			for t := range t.TypeArgs().Types() {
+				visit(t)
+			}
+		case *types.Alias:
+			for t := range t.TypeArgs().Types() {
+				visit(t)
+			}
+		case *types.TypeParam:
+			tns = append(tns, t.Obj())
+		case *types.Pointer:
+			visit(t.Elem())
+		case *types.Slice:
+			visit(t.Elem())
+		case *types.Array:
+			visit(t.Elem())
+		case *types.Chan:
+			visit(t.Elem())
+		case *types.Map:
+			visit(t.Key())
+			visit(t.Elem())
+		case *types.Struct:
+			for i := range t.NumFields() {
+				visit(t.Field(i).Type())
+			}
+		case *types.Signature:
+			// Ignore the receiver: although it may be present, it has no meaning
+			// in a type expression.
+			// Ditto for receiver type params.
+			// Also, function type params cannot appear in a type expression.
+			if t.TypeParams() != nil {
+				panic("Signature.TypeParams in type expression")
+			}
+			visit(t.Params())
+			visit(t.Results())
+		case *types.Interface:
+			for i := range t.NumEmbeddeds() {
+				visit(t.EmbeddedType(i))
+			}
+			for i := range t.NumExplicitMethods() {
+				visit(t.ExplicitMethod(i).Type())
+			}
+		case *types.Tuple:
+			for v := range t.Variables() {
+				visit(v.Type())
+			}
+		case *types.Union:
+			panic("Union in type expression")
+		default:
+			panic(fmt.Sprintf("unknown type %T", t))
+		}
+	}
+
+	visit(t)
+
+	return tns
+}
+
+// If con is an inlinable constant, suggest inlining its use at cur.
+func (a *analyzer) inlineConst(con *types.Const, cur inspector.Cursor) {
+	incon, ok := a.inlinableConsts[con]
+	if !ok {
+		var fact goFixInlineConstFact
+		if a.pass.ImportObjectFact(con, &fact) {
+			incon = &fact
+			a.inlinableConsts[con] = incon
+		}
+	}
+	if incon == nil {
+		return // nope
+	}
+
+	// If n is qualified by a package identifier, we'll need the full selector expression.
+	curFile := astutil.EnclosingFile(cur)
+	n := cur.Node().(*ast.Ident)
+
+	// We have an identifier A here (n), possibly qualified by a package identifier (sel.X,
+	// where sel is the parent of n), // and an inlinable "const A = B" elsewhere (incon).
+	// Consider replacing A with B.
+
+	// Check that the expression we are inlining (B) means the same thing
+	// (refers to the same object) in n's scope as it does in A's scope.
+	// If the RHS is not in the current package, AddImport will handle
+	// shadowing, so we only need to worry about when both expressions
+	// are in the current package.
+	if a.pass.Pkg.Path() == incon.RHSPkgPath {
+		// incon.rhsObj is the object referred to by B in the definition of A.
+		scope := a.pass.TypesInfo.Scopes[curFile].Innermost(n.Pos()) // n's scope
+		_, obj := scope.LookupParent(incon.RHSName, n.Pos())         // what "B" means in n's scope
+		if obj == nil {
+			// Should be impossible: if code at n can refer to the LHS,
+			// it can refer to the RHS.
+			panic(fmt.Sprintf("no object for inlinable const %s RHS %s", n.Name, incon.RHSName))
+		}
+		if obj != incon.rhsObj {
+			// "B" means something different here than at the inlinable const's scope.
+			return
+		}
+	} else if !packagepath.CanImport(a.pass.Pkg.Path(), incon.RHSPkgPath) {
+		// If this package can't see the RHS's package, we can't inline.
+		return
+	}
+	var (
+		importPrefix string
+		edits        []analysis.TextEdit
+	)
+	if incon.RHSPkgPath != a.pass.Pkg.Path() {
+		importPrefix, edits = refactor.AddImport(
+			a.pass.TypesInfo, curFile, incon.RHSPkgName, incon.RHSPkgPath, incon.RHSName, n.Pos())
+	}
+	// If n is qualified by a package identifier, we'll need the full selector expression.
+	var expr ast.Expr = n
+	if astutil.IsChildOf(cur, edge.SelectorExpr_Sel) {
+		expr = cur.Parent().Node().(ast.Expr)
+	}
+	a.reportInline("constant", "Constant", expr, edits, importPrefix+incon.RHSName)
+}
+
+// reportInline reports a diagnostic for fixing an inlinable name.
+func (a *analyzer) reportInline(kind, capKind string, ident ast.Expr, edits []analysis.TextEdit, newText string) {
+	edits = append(edits, analysis.TextEdit{
+		Pos:     ident.Pos(),
+		End:     ident.End(),
+		NewText: []byte(newText),
+	})
+	name := astutil.Format(a.pass.Fset, ident)
+	a.pass.Report(analysis.Diagnostic{
+		Pos:     ident.Pos(),
+		End:     ident.End(),
+		Message: fmt.Sprintf("%s %s should be inlined", capKind, name),
+		SuggestedFixes: []analysis.SuggestedFix{{
+			Message:   fmt.Sprintf("Inline %s %s", kind, name),
+			TextEdits: edits,
+		}},
+	})
+}
+
+func (a *analyzer) readFile(node ast.Node) ([]byte, error) {
+	filename := a.pass.Fset.File(node.Pos()).Name()
+	content, ok := a.fileContent[filename]
+	if !ok {
+		var err error
+		content, err = a.pass.ReadFile(filename)
+		if err != nil {
+			return nil, err
+		}
+		a.fileContent[filename] = content
+	}
+	return content, nil
+}
+
+// A goFixInlineFuncFact is exported for each function marked "//go:fix inline".
+// It holds information about the callee to support inlining.
+type goFixInlineFuncFact struct{ Callee *inline.Callee }
+
+func (f *goFixInlineFuncFact) String() string { return "goFixInline " + f.Callee.String() }
+func (*goFixInlineFuncFact) AFact()           {}
+
+// A goFixInlineConstFact is exported for each constant marked "//go:fix inline".
+// It holds information about an inlinable constant. Gob-serializable.
+type goFixInlineConstFact struct {
+	// Information about "const LHSName = RHSName".
+	RHSName    string
+	RHSPkgPath string
+	RHSPkgName string
+	rhsObj     types.Object // for current package
+}
+
+func (c *goFixInlineConstFact) String() string {
+	return fmt.Sprintf("goFixInline const %q.%s", c.RHSPkgPath, c.RHSName)
+}
+
+func (*goFixInlineConstFact) AFact() {}
+
+// A goFixInlineAliasFact is exported for each type alias marked "//go:fix inline".
+// It holds no information; its mere existence demonstrates that an alias is inlinable.
+type goFixInlineAliasFact struct{}
+
+func (c *goFixInlineAliasFact) String() string { return "goFixInline alias" }
+func (*goFixInlineAliasFact) AFact()           {}
+
+func discard(string, ...any) {}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/internal/gofixdirective/gofixdirective.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/internal/gofixdirective/gofixdirective.go
new file mode 100644
index 00000000000000..949df4bfeac76d
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/internal/gofixdirective/gofixdirective.go
@@ -0,0 +1,143 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package gofixdirective searches for and validates go:fix directives. The
+// go/analysis/passes/inline package uses findgofix to perform inlining.
+// The go/analysis/passes/gofix package uses findgofix to check for problems
+// with go:fix directives.
+//
+// gofixdirective is separate from gofix to avoid depending on refactor/inline,
+// which is large.
+package gofixdirective
+
+// This package is tested by go/analysis/passes/inline.
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/ast/inspector"
+	internalastutil "golang.org/x/tools/internal/astutil"
+)
+
+// A Handler handles language entities with go:fix directives.
+type Handler interface {
+	HandleFunc(*ast.FuncDecl)
+	HandleAlias(*ast.TypeSpec)
+	HandleConst(name, rhs *ast.Ident)
+}
+
+// Find finds functions and constants annotated with an appropriate "//go:fix"
+// comment (the syntax proposed by #32816), and calls handler methods for each one.
+// h may be nil.
+func Find(pass *analysis.Pass, root inspector.Cursor, h Handler) {
+	for cur := range root.Preorder((*ast.FuncDecl)(nil), (*ast.GenDecl)(nil)) {
+		switch decl := cur.Node().(type) {
+		case *ast.FuncDecl:
+			findFunc(decl, h)
+
+		case *ast.GenDecl:
+			if decl.Tok != token.CONST && decl.Tok != token.TYPE {
+				continue
+			}
+			declInline := hasFixInline(decl.Doc)
+			// Accept inline directives on the entire decl as well as individual specs.
+			for _, spec := range decl.Specs {
+				switch spec := spec.(type) {
+				case *ast.TypeSpec: // Tok == TYPE
+					findAlias(pass, spec, declInline, h)
+
+				case *ast.ValueSpec: // Tok == CONST
+					findConst(pass, spec, declInline, h)
+				}
+			}
+		}
+	}
+}
+
+func findFunc(decl *ast.FuncDecl, h Handler) {
+	if !hasFixInline(decl.Doc) {
+		return
+	}
+	if h != nil {
+		h.HandleFunc(decl)
+	}
+}
+
+func findAlias(pass *analysis.Pass, spec *ast.TypeSpec, declInline bool, h Handler) {
+	if !declInline && !hasFixInline(spec.Doc) {
+		return
+	}
+	if !spec.Assign.IsValid() {
+		pass.Reportf(spec.Pos(), "invalid //go:fix inline directive: not a type alias")
+		return
+	}
+
+	// Disallow inlines of type expressions containing array types.
+	// Given an array type like [N]int where N is a named constant, go/types provides
+	// only the value of the constant as an int64. So inlining A in this code:
+	//
+	//    const N = 5
+	//    type A = [N]int
+	//
+	// would result in [5]int, breaking the connection with N.
+	for n := range ast.Preorder(spec.Type) {
+		if ar, ok := n.(*ast.ArrayType); ok && ar.Len != nil {
+			// Make an exception when the array length is a literal int.
+			if lit, ok := ast.Unparen(ar.Len).(*ast.BasicLit); ok && lit.Kind == token.INT {
+				continue
+			}
+			pass.Reportf(spec.Pos(), "invalid //go:fix inline directive: array types not supported")
+			return
+		}
+	}
+	if h != nil {
+		h.HandleAlias(spec)
+	}
+}
+
+func findConst(pass *analysis.Pass, spec *ast.ValueSpec, declInline bool, h Handler) {
+	specInline := hasFixInline(spec.Doc)
+	if declInline || specInline {
+		for i, nameIdent := range spec.Names {
+			if i >= len(spec.Values) {
+				// Possible following an iota.
+				break
+			}
+			var rhsIdent *ast.Ident
+			switch val := spec.Values[i].(type) {
+			case *ast.Ident:
+				// Constants defined with the predeclared iota cannot be inlined.
+				if pass.TypesInfo.Uses[val] == builtinIota {
+					pass.Reportf(val.Pos(), "invalid //go:fix inline directive: const value is iota")
+					return
+				}
+				rhsIdent = val
+			case *ast.SelectorExpr:
+				rhsIdent = val.Sel
+			default:
+				pass.Reportf(val.Pos(), "invalid //go:fix inline directive: const value is not the name of another constant")
+				return
+			}
+			if h != nil {
+				h.HandleConst(nameIdent, rhsIdent)
+			}
+		}
+	}
+}
+
+// hasFixInline reports the presence of a "//go:fix inline" directive
+// in the comments.
+func hasFixInline(cg *ast.CommentGroup) bool {
+	for _, d := range internalastutil.Directives(cg) {
+		if d.Tool == "go" && d.Name == "fix" && d.Args == "inline" {
+			return true
+		}
+	}
+	return false
+}
+
+var builtinIota = types.Universe.Lookup("iota")
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/any.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/any.go
new file mode 100644
index 00000000000000..05999f8f2b78b5
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/any.go
@@ -0,0 +1,61 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"go/ast"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+)
+
+var AnyAnalyzer = &analysis.Analyzer{
+	Name: "any",
+	Doc:  analysisinternal.MustExtractDoc(doc, "any"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+	},
+	Run: runAny,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#any",
+}
+
+// The any pass replaces interface{} with go1.18's 'any'.
+func runAny(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+	for curFile := range filesUsing(inspect, pass.TypesInfo, "go1.18") {
+		for curIface := range curFile.Preorder((*ast.InterfaceType)(nil)) {
+			iface := curIface.Node().(*ast.InterfaceType)
+
+			if iface.Methods.NumFields() == 0 {
+				// Check that 'any' is not shadowed.
+				if lookup(pass.TypesInfo, curIface, "any") == builtinAny {
+					pass.Report(analysis.Diagnostic{
+						Pos:     iface.Pos(),
+						End:     iface.End(),
+						Message: "interface{} can be replaced by any",
+						SuggestedFixes: []analysis.SuggestedFix{{
+							Message: "Replace interface{} by any",
+							TextEdits: []analysis.TextEdit{
+								{
+									Pos:     iface.Pos(),
+									End:     iface.End(),
+									NewText: []byte("any"),
+								},
+							},
+						}},
+					})
+				}
+			}
+		}
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/bloop.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/bloop.go
new file mode 100644
index 00000000000000..eb1ac170c6933c
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/bloop.go
@@ -0,0 +1,250 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/moreiters"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var BLoopAnalyzer = &analysis.Analyzer{
+	Name: "bloop",
+	Doc:  analysisinternal.MustExtractDoc(doc, "bloop"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: bloop,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#bloop",
+}
+
+// bloop updates benchmarks that use "for range b.N", replacing it
+// with go1.24's b.Loop() and eliminating any preceding
+// b.{Start,Stop,Reset}Timer calls.
+//
+// Variants:
+//
+//	for i := 0; i < b.N; i++ {}  =>   for b.Loop() {}
+//	for range b.N {}
+func bloop(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	if !typesinternal.Imports(pass.Pkg, "testing") {
+		return nil, nil
+	}
+
+	var (
+		inspect = pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		index   = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info    = pass.TypesInfo
+	)
+
+	// edits computes the text edits for a matched for/range loop
+	// at the specified cursor. b is the *testing.B value, and
+	// (start, end) is the portion using b.N to delete.
+	edits := func(curLoop inspector.Cursor, b ast.Expr, start, end token.Pos) (edits []analysis.TextEdit) {
+		curFn, _ := enclosingFunc(curLoop)
+		// Within the same function, delete all calls to
+		// b.{Start,Stop,Timer} that precede the loop.
+		filter := []ast.Node{(*ast.ExprStmt)(nil), (*ast.FuncLit)(nil)}
+		curFn.Inspect(filter, func(cur inspector.Cursor) (descend bool) {
+			node := cur.Node()
+			if is[*ast.FuncLit](node) {
+				return false // don't descend into FuncLits (e.g. sub-benchmarks)
+			}
+			stmt := node.(*ast.ExprStmt)
+			if stmt.Pos() > start {
+				return false // not preceding: stop
+			}
+			if call, ok := stmt.X.(*ast.CallExpr); ok {
+				obj := typeutil.Callee(info, call)
+				if typesinternal.IsMethodNamed(obj, "testing", "B", "StopTimer", "StartTimer", "ResetTimer") {
+					// Delete call statement.
+					// TODO(adonovan): delete following newline, or
+					// up to start of next stmt? (May delete a comment.)
+					edits = append(edits, analysis.TextEdit{
+						Pos: stmt.Pos(),
+						End: stmt.End(),
+					})
+				}
+			}
+			return true
+		})
+
+		// Replace ...b.N... with b.Loop().
+		return append(edits, analysis.TextEdit{
+			Pos:     start,
+			End:     end,
+			NewText: fmt.Appendf(nil, "%s.Loop()", astutil.Format(pass.Fset, b)),
+		})
+	}
+
+	// Find all for/range statements.
+	loops := []ast.Node{
+		(*ast.ForStmt)(nil),
+		(*ast.RangeStmt)(nil),
+	}
+	for curFile := range filesUsing(inspect, info, "go1.24") {
+		for curLoop := range curFile.Preorder(loops...) {
+			switch n := curLoop.Node().(type) {
+			case *ast.ForStmt:
+				// for _; i < b.N; _ {}
+				if cmp, ok := n.Cond.(*ast.BinaryExpr); ok && cmp.Op == token.LSS {
+					if sel, ok := cmp.Y.(*ast.SelectorExpr); ok &&
+						sel.Sel.Name == "N" &&
+						typesinternal.IsPointerToNamed(info.TypeOf(sel.X), "testing", "B") && usesBenchmarkNOnce(curLoop, info) {
+
+						delStart, delEnd := n.Cond.Pos(), n.Cond.End()
+
+						// Eliminate variable i if no longer needed:
+						//  for i := 0; i < b.N; i++ {
+						//    ...no references to i...
+						//  }
+						body, _ := curLoop.LastChild()
+						if v := isIncrementLoop(info, n); v != nil &&
+							!uses(index, body, v) {
+							delStart, delEnd = n.Init.Pos(), n.Post.End()
+						}
+
+						pass.Report(analysis.Diagnostic{
+							// Highlight "i < b.N".
+							Pos:     n.Cond.Pos(),
+							End:     n.Cond.End(),
+							Message: "b.N can be modernized using b.Loop()",
+							SuggestedFixes: []analysis.SuggestedFix{{
+								Message:   "Replace b.N with b.Loop()",
+								TextEdits: edits(curLoop, sel.X, delStart, delEnd),
+							}},
+						})
+					}
+				}
+
+			case *ast.RangeStmt:
+				// for range b.N {} -> for b.Loop() {}
+				//
+				// TODO(adonovan): handle "for i := range b.N".
+				if sel, ok := n.X.(*ast.SelectorExpr); ok &&
+					n.Key == nil &&
+					n.Value == nil &&
+					sel.Sel.Name == "N" &&
+					typesinternal.IsPointerToNamed(info.TypeOf(sel.X), "testing", "B") && usesBenchmarkNOnce(curLoop, info) {
+
+					pass.Report(analysis.Diagnostic{
+						// Highlight "range b.N".
+						Pos:     n.Range,
+						End:     n.X.End(),
+						Message: "b.N can be modernized using b.Loop()",
+						SuggestedFixes: []analysis.SuggestedFix{{
+							Message:   "Replace b.N with b.Loop()",
+							TextEdits: edits(curLoop, sel.X, n.Range, n.X.End()),
+						}},
+					})
+				}
+			}
+		}
+	}
+	return nil, nil
+}
+
+// uses reports whether the subtree cur contains a use of obj.
+func uses(index *typeindex.Index, cur inspector.Cursor, obj types.Object) bool {
+	for use := range index.Uses(obj) {
+		if cur.Contains(use) {
+			return true
+		}
+	}
+	return false
+}
+
+// enclosingFunc returns the cursor for the innermost Func{Decl,Lit}
+// that encloses c, if any.
+func enclosingFunc(c inspector.Cursor) (inspector.Cursor, bool) {
+	return moreiters.First(c.Enclosing((*ast.FuncDecl)(nil), (*ast.FuncLit)(nil)))
+}
+
+// usesBenchmarkNOnce reports whether a b.N loop should be modernized to b.Loop().
+// Only modernize loops that are:
+// 1. Directly in a benchmark function (not in nested functions)
+//   - b.Loop() must be called in the same goroutine as the benchmark function
+//   - Function literals are often used with goroutines (go func(){...})
+//
+// 2. The only b.N loop in that benchmark function
+//   - b.Loop() can only be called once per benchmark execution
+//   - Multiple calls result in "B.Loop called with timer stopped" error
+func usesBenchmarkNOnce(c inspector.Cursor, info *types.Info) bool {
+	// Find the enclosing benchmark function
+	curFunc, ok := enclosingFunc(c)
+	if !ok {
+		return false
+	}
+
+	// Check if this is actually a benchmark function
+	fdecl, ok := curFunc.Node().(*ast.FuncDecl)
+	if !ok {
+		return false // not in a function; or, inside a FuncLit
+	}
+	if !isBenchmarkFunc(fdecl) {
+		return false
+	}
+
+	// Count b.N references in this benchmark function
+	bnRefCount := 0
+	filter := []ast.Node{(*ast.SelectorExpr)(nil), (*ast.FuncLit)(nil)}
+	curFunc.Inspect(filter, func(cur inspector.Cursor) bool {
+		switch n := cur.Node().(type) {
+		case *ast.FuncLit:
+			return false // don't descend into nested function literals
+		case *ast.SelectorExpr:
+			if n.Sel.Name == "N" && typesinternal.IsPointerToNamed(info.TypeOf(n.X), "testing", "B") {
+				bnRefCount++
+			}
+		}
+		return true
+	})
+
+	// Only modernize if there's exactly one b.N reference
+	return bnRefCount == 1
+}
+
+// isBenchmarkFunc reports whether f is a benchmark function.
+func isBenchmarkFunc(f *ast.FuncDecl) bool {
+	return f.Recv == nil &&
+		f.Name != nil &&
+		f.Name.IsExported() &&
+		strings.HasPrefix(f.Name.Name, "Benchmark") &&
+		f.Type.Params != nil &&
+		len(f.Type.Params.List) == 1
+}
+
+// isIncrementLoop reports whether loop has the form "for i := 0; ...; i++ { ... }",
+// and if so, it returns the symbol for the index variable.
+func isIncrementLoop(info *types.Info, loop *ast.ForStmt) *types.Var {
+	if assign, ok := loop.Init.(*ast.AssignStmt); ok &&
+		assign.Tok == token.DEFINE &&
+		len(assign.Rhs) == 1 &&
+		isZeroIntLiteral(info, assign.Rhs[0]) &&
+		is[*ast.IncDecStmt](loop.Post) &&
+		loop.Post.(*ast.IncDecStmt).Tok == token.INC &&
+		astutil.EqualSyntax(loop.Post.(*ast.IncDecStmt).X, assign.Lhs[0]) {
+		return info.Defs[assign.Lhs[0].(*ast.Ident)].(*types.Var)
+	}
+	return nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/doc.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/doc.go
new file mode 100644
index 00000000000000..bc143d7a6d0f16
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/doc.go
@@ -0,0 +1,455 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package modernize provides a suite of analyzers that suggest
+simplifications to Go code, using modern language and library
+features.
+
+Each diagnostic provides a fix. Our intent is that these fixes may
+be safely applied en masse without changing the behavior of your
+program. In some cases the suggested fixes are imperfect and may
+lead to (for example) unused imports or unused local variables,
+causing build breakage. However, these problems are generally
+trivial to fix. We regard any modernizer whose fix changes program
+behavior to have a serious bug and will endeavor to fix it.
+
+To apply all modernization fixes en masse, you can use the
+following command:
+
+	$ go run golang.org/x/tools/go/analysis/passes/modernize/cmd/modernize@latest -fix ./...
+
+(Do not use "go get -tool" to add gopls as a dependency of your
+module; gopls commands must be built from their release branch.)
+
+If the tool warns of conflicting fixes, you may need to run it more
+than once until it has applied all fixes cleanly. This command is
+not an officially supported interface and may change in the future.
+
+Changes produced by this tool should be reviewed as usual before
+being merged. In some cases, a loop may be replaced by a simple
+function call, causing comments within the loop to be discarded.
+Human judgment may be required to avoid losing comments of value.
+
+The modernize suite contains many analyzers. Diagnostics from some,
+such as "any" (which replaces "interface{}" with "any" where it
+is safe to do so), are particularly numerous. It may ease the burden of
+code review to apply fixes in two steps, the first consisting only of
+fixes from the "any" analyzer, the second consisting of all
+other analyzers. This can be achieved using flags, as in this example:
+
+	$ modernize -any=true  -fix ./...
+	$ modernize -any=false -fix ./...
+
+# Analyzer appendclipped
+
+appendclipped: simplify append chains using slices.Concat
+
+The appendclipped analyzer suggests replacing chains of append calls with a
+single call to slices.Concat, which was added in Go 1.21. For example,
+append(append(s, s1...), s2...) would be simplified to slices.Concat(s, s1, s2).
+
+In the simple case of appending to a newly allocated slice, such as
+append([]T(nil), s...), the analyzer suggests the more concise slices.Clone(s).
+For byte slices, it will prefer bytes.Clone if the "bytes" package is
+already imported.
+
+This fix is only applied when the base of the append tower is a
+"clipped" slice, meaning its length and capacity are equal (e.g.
+x[:0:0] or []T{}). This is to avoid changing program behavior by
+eliminating intended side effects on the base slice's underlying
+array.
+
+This analyzer is currently disabled by default as the
+transformation does not preserve the nilness of the base slice in
+all cases; see https://go.dev/issue/73557.
+
+# Analyzer bloop
+
+bloop: replace for-range over b.N with b.Loop
+
+The bloop analyzer suggests replacing benchmark loops of the form
+`for i := 0; i < b.N; i++` or `for range b.N` with the more modern
+`for b.Loop()`, which was added in Go 1.24.
+
+This change makes benchmark code more readable and also removes the need for
+manual timer control, so any preceding calls to b.StartTimer, b.StopTimer,
+or b.ResetTimer within the same function will also be removed.
+
+Caveats: The b.Loop() method is designed to prevent the compiler from
+optimizing away the benchmark loop, which can occasionally result in
+slower execution due to increased allocations in some specific cases.
+
+# Analyzer any
+
+any: replace interface{} with any
+
+The any analyzer suggests replacing uses of the empty interface type,
+`interface{}`, with the `any` alias, which was introduced in Go 1.18.
+This is a purely stylistic change that makes code more readable.
+
+# Analyzer errorsastype
+
+errorsastype: replace errors.As with errors.AsType[T]
+
+This analyzer suggests fixes to simplify uses of [errors.As] of
+this form:
+
+	var myerr *MyErr
+	if errors.As(err, &myerr) {
+		handle(myerr)
+	}
+
+by using the less error-prone generic [errors.AsType] function,
+introduced in Go 1.26:
+
+	if myerr, ok := errors.AsType[*MyErr](err); ok {
+		handle(myerr)
+	}
+
+The fix is only offered if the var declaration has the form shown and
+there are no uses of myerr outside the if statement.
+
+# Analyzer fmtappendf
+
+fmtappendf: replace []byte(fmt.Sprintf) with fmt.Appendf
+
+The fmtappendf analyzer suggests replacing `[]byte(fmt.Sprintf(...))` with
+`fmt.Appendf(nil, ...)`. This avoids the intermediate allocation of a string
+by Sprintf, making the code more efficient. The suggestion also applies to
+fmt.Sprint and fmt.Sprintln.
+
+# Analyzer forvar
+
+forvar: remove redundant re-declaration of loop variables
+
+The forvar analyzer removes unnecessary shadowing of loop variables.
+Before Go 1.22, it was common to write `for _, x := range s { x := x ... }`
+to create a fresh variable for each iteration. Go 1.22 changed the semantics
+of `for` loops, making this pattern redundant. This analyzer removes the
+unnecessary `x := x` statement.
+
+This fix only applies to `range` loops.
+
+# Analyzer mapsloop
+
+mapsloop: replace explicit loops over maps with calls to maps package
+
+The mapsloop analyzer replaces loops of the form
+
+	for k, v := range x { m[k] = v }
+
+with a single call to a function from the `maps` package, added in Go 1.23.
+Depending on the context, this could be `maps.Copy`, `maps.Insert`,
+`maps.Clone`, or `maps.Collect`.
+
+The transformation to `maps.Clone` is applied conservatively, as it
+preserves the nilness of the source map, which may be a subtle change in
+behavior if the original code did not handle a nil map in the same way.
+
+# Analyzer minmax
+
+minmax: replace if/else statements with calls to min or max
+
+The minmax analyzer simplifies conditional assignments by suggesting the use
+of the built-in `min` and `max` functions, introduced in Go 1.21. For example,
+
+	if a < b { x = a } else { x = b }
+
+is replaced by
+
+	x = min(a, b).
+
+This analyzer avoids making suggestions for floating-point types,
+as the behavior of `min` and `max` with NaN values can differ from
+the original if/else statement.
+
+# Analyzer newexpr
+
+newexpr: simplify code by using go1.26's new(expr)
+
+This analyzer finds declarations of functions of this form:
+
+	func varOf(x int) *int { return &x }
+
+and suggests a fix to turn them into inlinable wrappers around
+go1.26's built-in new(expr) function:
+
+	func varOf(x int) *int { return new(x) }
+
+In addition, this analyzer suggests a fix for each call
+to one of the functions before it is transformed, so that
+
+	use(varOf(123))
+
+is replaced by:
+
+	use(new(123))
+
+(Wrapper functions such as varOf are common when working with Go
+serialization packages such as for JSON or protobuf, where pointers
+are often used to express optionality.)
+
+# Analyzer omitzero
+
+omitzero: suggest replacing omitempty with omitzero for struct fields
+
+The omitzero analyzer identifies uses of the `omitempty` JSON struct tag on
+fields that are themselves structs. The `omitempty` tag has no effect on
+struct-typed fields. The analyzer offers two suggestions: either remove the
+tag, or replace it with `omitzero` (added in Go 1.24), which correctly
+omits the field if the struct value is zero.
+
+Replacing `omitempty` with `omitzero` is a change in behavior. The
+original code would always encode the struct field, whereas the
+modified code will omit it if it is a zero-value.
+
+# Analyzer plusbuild
+
+plusbuild: remove obsolete //+build comments
+
+The plusbuild analyzer suggests a fix to remove obsolete build tags
+of the form:
+
+	//+build linux,amd64
+
+in files that also contain a Go 1.18-style tag such as:
+
+	//go:build linux && amd64
+
+(It does not check that the old and new tags are consistent;
+that is the job of the 'buildtag' analyzer in the vet suite.)
+
+# Analyzer rangeint
+
+rangeint: replace 3-clause for loops with for-range over integers
+
+The rangeint analyzer suggests replacing traditional for loops such
+as
+
+	for i := 0; i < n; i++ { ... }
+
+with the more idiomatic Go 1.22 style:
+
+	for i := range n { ... }
+
+This transformation is applied only if (a) the loop variable is not
+modified within the loop body and (b) the loop's limit expression
+is not modified within the loop, as `for range` evaluates its
+operand only once.
+
+# Analyzer reflecttypefor
+
+reflecttypefor: replace reflect.TypeOf(x) with TypeFor[T]()
+
+This analyzer suggests fixes to replace uses of reflect.TypeOf(x) with
+reflect.TypeFor, introduced in go1.22, when the desired runtime type
+is known at compile time, for example:
+
+	reflect.TypeOf(uint32(0))        -> reflect.TypeFor[uint32]()
+	reflect.TypeOf((*ast.File)(nil)) -> reflect.TypeFor[*ast.File]()
+
+It also offers a fix to simplify the construction below, which uses
+reflect.TypeOf to return the runtime type for an interface type,
+
+	reflect.TypeOf((*io.Reader)(nil)).Elem()
+
+to:
+
+	reflect.TypeFor[io.Reader]()
+
+No fix is offered in cases when the runtime type is dynamic, such as:
+
+	var r io.Reader = ...
+	reflect.TypeOf(r)
+
+or when the operand has potential side effects.
+
+# Analyzer slicescontains
+
+slicescontains: replace loops with slices.Contains or slices.ContainsFunc
+
+The slicescontains analyzer simplifies loops that check for the existence of
+an element in a slice. It replaces them with calls to `slices.Contains` or
+`slices.ContainsFunc`, which were added in Go 1.21.
+
+If the expression for the target element has side effects, this
+transformation will cause those effects to occur only once, not
+once per tested slice element.
+
+# Analyzer slicesdelete
+
+slicesdelete: replace append-based slice deletion with slices.Delete
+
+The slicesdelete analyzer suggests replacing the idiom
+
+	s = append(s[:i], s[j:]...)
+
+with the more explicit
+
+	s = slices.Delete(s, i, j)
+
+introduced in Go 1.21.
+
+This analyzer is disabled by default. The `slices.Delete` function
+zeros the elements between the new length and the old length of the
+slice to prevent memory leaks, which is a subtle difference in
+behavior compared to the append-based idiom; see https://go.dev/issue/73686.
+
+# Analyzer slicessort
+
+slicessort: replace sort.Slice with slices.Sort for basic types
+
+The slicessort analyzer simplifies sorting slices of basic ordered
+types. It replaces
+
+	sort.Slice(s, func(i, j int) bool { return s[i] < s[j] })
+
+with the simpler `slices.Sort(s)`, which was added in Go 1.21.
+
+# Analyzer stditerators
+
+stditerators: use iterators instead of Len/At-style APIs
+
+This analyzer suggests a fix to replace each loop of the form:
+
+	for i := 0; i < x.Len(); i++ {
+		use(x.At(i))
+	}
+
+or its "for elem := range x.Len()" equivalent by a range loop over an
+iterator offered by the same data type:
+
+	for elem := range x.All() {
+		use(x.At(i)
+	}
+
+where x is one of various well-known types in the standard library.
+
+# Analyzer stringscutprefix
+
+stringscutprefix: replace HasPrefix/TrimPrefix with CutPrefix
+
+The stringscutprefix analyzer simplifies a common pattern where code first
+checks for a prefix with `strings.HasPrefix` and then removes it with
+`strings.TrimPrefix`. It replaces this two-step process with a single call
+to `strings.CutPrefix`, introduced in Go 1.20. The analyzer also handles
+the equivalent functions in the `bytes` package.
+
+For example, this input:
+
+	if strings.HasPrefix(s, prefix) {
+	    use(strings.TrimPrefix(s, prefix))
+	}
+
+is fixed to:
+
+	if after, ok := strings.CutPrefix(s, prefix); ok {
+	    use(after)
+	}
+
+The analyzer also offers fixes to use CutSuffix in a similar way.
+This input:
+
+	if strings.HasSuffix(s, suffix) {
+	    use(strings.TrimSuffix(s, suffix))
+	}
+
+is fixed to:
+
+	if before, ok := strings.CutSuffix(s, suffix); ok {
+	    use(before)
+	}
+
+# Analyzer stringsseq
+
+stringsseq: replace ranging over Split/Fields with SplitSeq/FieldsSeq
+
+The stringsseq analyzer improves the efficiency of iterating over substrings.
+It replaces
+
+	for range strings.Split(...)
+
+with the more efficient
+
+	for range strings.SplitSeq(...)
+
+which was added in Go 1.24 and avoids allocating a slice for the
+substrings. The analyzer also handles strings.Fields and the
+equivalent functions in the bytes package.
+
+# Analyzer stringsbuilder
+
+stringsbuilder: replace += with strings.Builder
+
+This analyzer replaces repeated string += string concatenation
+operations with calls to Go 1.10's strings.Builder.
+
+For example:
+
+	var s = "["
+	for x := range seq {
+		s += x
+		s += "."
+	}
+	s += "]"
+	use(s)
+
+is replaced by:
+
+	var s strings.Builder
+	s.WriteString("[")
+	for x := range seq {
+		s.WriteString(x)
+		s.WriteString(".")
+	}
+	s.WriteString("]")
+	use(s.String())
+
+This avoids quadratic memory allocation and improves performance.
+
+The analyzer requires that all references to s except the final one
+are += operations. To avoid warning about trivial cases, at least one
+must appear within a loop. The variable s must be a local
+variable, not a global or parameter.
+
+The sole use of the finished string must be the last reference to the
+variable s. (It may appear within an intervening loop or function literal,
+since even s.String() is called repeatedly, it does not allocate memory.)
+
+# Analyzer testingcontext
+
+testingcontext: replace context.WithCancel with t.Context in tests
+
+The testingcontext analyzer simplifies context management in tests. It
+replaces the manual creation of a cancellable context,
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+with a single call to t.Context(), which was added in Go 1.24.
+
+This change is only suggested if the `cancel` function is not used
+for any other purpose.
+
+# Analyzer waitgroup
+
+waitgroup: replace wg.Add(1)/go/wg.Done() with wg.Go
+
+The waitgroup analyzer simplifies goroutine management with `sync.WaitGroup`.
+It replaces the common pattern
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		...
+	}()
+
+with a single call to
+
+	wg.Go(func(){ ... })
+
+which was added in Go 1.25.
+*/
+package modernize
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/errorsastype.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/errorsastype.go
new file mode 100644
index 00000000000000..b6387ad8406033
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/errorsastype.go
@@ -0,0 +1,243 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"fmt"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/goplsexport"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var errorsastypeAnalyzer = &analysis.Analyzer{
+	Name:     "errorsastype",
+	Doc:      analysisinternal.MustExtractDoc(doc, "errorsastype"),
+	URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#errorsastype",
+	Requires: []*analysis.Analyzer{generated.Analyzer, typeindexanalyzer.Analyzer},
+	Run:      errorsastype,
+}
+
+func init() {
+	// Export to gopls until this is a published modernizer.
+	goplsexport.ErrorsAsTypeModernizer = errorsastypeAnalyzer
+}
+
+// errorsastype offers a fix to replace error.As with the newer
+// errors.AsType[T] following this pattern:
+//
+//	var myerr *MyErr
+//	if errors.As(err, &myerr) { ... }
+//
+// =>
+//
+//	if myerr, ok := errors.AsType[*MyErr](err); ok  { ... }
+//
+// (In principle several of these can then be chained using if/else,
+// but we don't attempt that.)
+//
+// We offer the fix only within an if statement, but not within a
+// switch case such as:
+//
+//	var myerr *MyErr
+//	switch {
+//	case errors.As(err, &myerr):
+//	}
+//
+// because the transformation in that case would be ungainly.
+//
+// Note that the cmd/vet suite includes the "errorsas" analyzer, which
+// detects actual mistakes in the use of errors.As. This logic does
+// not belong in errorsas because the problems it fixes are merely
+// stylistic.
+//
+// TODO(adonovan): support more cases:
+//
+//   - Negative cases
+//     var myerr E
+//     if !errors.As(err, &myerr) { ... }
+//     =>
+//     myerr, ok := errors.AsType[E](err)
+//     if !ok { ... }
+//
+// - if myerr := new(E); errors.As(err, myerr); { ... }
+//
+// - if errors.As(err, myerr) && othercond { ... }
+func errorsastype(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	var (
+		index = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info  = pass.TypesInfo
+	)
+
+	for curCall := range index.Calls(index.Object("errors", "As")) {
+		call := curCall.Node().(*ast.CallExpr)
+		if len(call.Args) < 2 {
+			continue // spread call: errors.As(pair())
+		}
+
+		v, curDeclStmt := canUseErrorsAsType(info, index, curCall)
+		if v == nil {
+			continue
+		}
+
+		file := astutil.EnclosingFile(curDeclStmt)
+		if !fileUses(info, file, "go1.26") {
+			continue // errors.AsType is too new
+		}
+
+		// Locate identifier "As" in errors.As.
+		var asIdent *ast.Ident
+		switch n := ast.Unparen(call.Fun).(type) {
+		case *ast.Ident:
+			asIdent = n // "errors" was dot-imported
+		case *ast.SelectorExpr:
+			asIdent = n.Sel
+		default:
+			panic("no Ident for errors.As")
+		}
+
+		// Format the type as valid Go syntax.
+		// TODO(adonovan): fix: FileQualifier needs to respect
+		// visibility at the current point, and either fail
+		// or edit the imports as needed.
+		// TODO(adonovan): fix: TypeString is not a sound way
+		// to print types as Go syntax as it does not respect
+		// symbol visibility, etc. We need something loosely
+		// integrated with FileQualifier that accumulates
+		// import edits, and may fail (e.g. for unexported
+		// type or field names from other packages).
+		// See https://go.dev/issues/75604.
+		qual := typesinternal.FileQualifier(file, pass.Pkg)
+		errtype := types.TypeString(v.Type(), qual)
+
+		// Choose a name for the "ok" variable.
+		okName := "ok"
+		if okVar := lookup(info, curCall, "ok"); okVar != nil {
+			// The name 'ok' is already declared, but
+			// don't choose a fresh name unless okVar
+			// is also used within the if-statement.
+			curIf := curCall.Parent()
+			for curUse := range index.Uses(okVar) {
+				if curIf.Contains(curUse) {
+					scope := info.Scopes[curIf.Node().(*ast.IfStmt)]
+					okName = refactor.FreshName(scope, v.Pos(), "ok")
+					break
+				}
+			}
+		}
+
+		pass.Report(analysis.Diagnostic{
+			Pos:     call.Fun.Pos(),
+			End:     call.Fun.End(),
+			Message: fmt.Sprintf("errors.As can be simplified using AsType[%s]", errtype),
+			SuggestedFixes: []analysis.SuggestedFix{{
+				Message: fmt.Sprintf("Replace errors.As with AsType[%s]", errtype),
+				TextEdits: append(
+					// delete "var myerr *MyErr"
+					refactor.DeleteStmt(pass.Fset.File(call.Fun.Pos()), curDeclStmt),
+					// if              errors.As            (err, &myerr)     { ... }
+					//    -------------       --------------    -------- ----
+					// if myerr, ok := errors.AsType[*MyErr](err        ); ok { ... }
+					analysis.TextEdit{
+						// insert "myerr, ok := "
+						Pos:     call.Pos(),
+						End:     call.Pos(),
+						NewText: fmt.Appendf(nil, "%s, %s := ", v.Name(), okName),
+					},
+					analysis.TextEdit{
+						// replace As with AsType[T]
+						Pos:     asIdent.Pos(),
+						End:     asIdent.End(),
+						NewText: fmt.Appendf(nil, "AsType[%s]", errtype),
+					},
+					analysis.TextEdit{
+						// delete ", &myerr"
+						Pos: call.Args[0].End(),
+						End: call.Args[1].End(),
+					},
+					analysis.TextEdit{
+						// insert "; ok"
+						Pos:     call.End(),
+						End:     call.End(),
+						NewText: fmt.Appendf(nil, "; %s", okName),
+					},
+				),
+			}},
+		})
+	}
+	return nil, nil
+}
+
+// canUseErrorsAsType reports whether curCall is a call to
+// errors.As beneath an if statement, preceded by a
+// declaration of the typed error var. The var must not be
+// used outside the if statement.
+func canUseErrorsAsType(info *types.Info, index *typeindex.Index, curCall inspector.Cursor) (_ *types.Var, _ inspector.Cursor) {
+	if !astutil.IsChildOf(curCall, edge.IfStmt_Cond) {
+		return // not beneath if statement
+	}
+	var (
+		curIfStmt = curCall.Parent()
+		ifStmt    = curIfStmt.Node().(*ast.IfStmt)
+	)
+	if ifStmt.Init != nil {
+		return // if statement already has an init part
+	}
+	unary, ok := curCall.Node().(*ast.CallExpr).Args[1].(*ast.UnaryExpr)
+	if !ok || unary.Op != token.AND {
+		return // 2nd arg is not &var
+	}
+	id, ok := unary.X.(*ast.Ident)
+	if !ok {
+		return // not a simple ident (local var)
+	}
+	v := info.Uses[id].(*types.Var)
+	curDef, ok := index.Def(v)
+	if !ok {
+		return // var is not local (e.g. dot-imported)
+	}
+	// Have: if errors.As(err, &v) { ... }
+
+	// Reject if v is used outside (before or after) the
+	// IfStmt, since that will become its new scope.
+	for curUse := range index.Uses(v) {
+		if !curIfStmt.Contains(curUse) {
+			return // v used before/after if statement
+		}
+	}
+	if !astutil.IsChildOf(curDef, edge.ValueSpec_Names) {
+		return // v not declared by "var v T"
+	}
+	var (
+		curSpec = curDef.Parent()  // ValueSpec
+		curDecl = curSpec.Parent() // GenDecl
+		spec    = curSpec.Node().(*ast.ValueSpec)
+	)
+	if len(spec.Names) != 1 || len(spec.Values) != 0 ||
+		len(curDecl.Node().(*ast.GenDecl).Specs) != 1 {
+		return // not a simple "var v T" decl
+	}
+
+	// Have:
+	//   var v *MyErr
+	//   ...
+	//   if errors.As(err, &v) { ... }
+	// with no uses of v outside the IfStmt.
+	return v, curDecl.Parent() // DeclStmt
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/fmtappendf.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/fmtappendf.go
new file mode 100644
index 00000000000000..f2e536054248c8
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/fmtappendf.go
@@ -0,0 +1,115 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var FmtAppendfAnalyzer = &analysis.Analyzer{
+	Name: "fmtappendf",
+	Doc:  analysisinternal.MustExtractDoc(doc, "fmtappendf"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: fmtappendf,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#fmtappendf",
+}
+
+// The fmtappend function replaces []byte(fmt.Sprintf(...)) by
+// fmt.Appendf(nil, ...), and similarly for Sprint, Sprintln.
+func fmtappendf(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	index := pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+	for _, fn := range []types.Object{
+		index.Object("fmt", "Sprintf"),
+		index.Object("fmt", "Sprintln"),
+		index.Object("fmt", "Sprint"),
+	} {
+		for curCall := range index.Calls(fn) {
+			call := curCall.Node().(*ast.CallExpr)
+			if ek, idx := curCall.ParentEdge(); ek == edge.CallExpr_Args && idx == 0 {
+				// Is parent a T(fmt.SprintX(...)) conversion?
+				conv := curCall.Parent().Node().(*ast.CallExpr)
+				tv := pass.TypesInfo.Types[conv.Fun]
+				if tv.IsType() && types.Identical(tv.Type, byteSliceType) &&
+					fileUses(pass.TypesInfo, astutil.EnclosingFile(curCall), "go1.19") {
+					// Have: []byte(fmt.SprintX(...))
+
+					// Find "Sprint" identifier.
+					var id *ast.Ident
+					switch e := ast.Unparen(call.Fun).(type) {
+					case *ast.SelectorExpr:
+						id = e.Sel // "fmt.Sprint"
+					case *ast.Ident:
+						id = e // "Sprint" after `import . "fmt"`
+					}
+
+					old, new := fn.Name(), strings.Replace(fn.Name(), "Sprint", "Append", 1)
+					edits := []analysis.TextEdit{
+						{
+							// delete "[]byte("
+							Pos: conv.Pos(),
+							End: conv.Lparen + 1,
+						},
+						{
+							// remove ")"
+							Pos: conv.Rparen,
+							End: conv.Rparen + 1,
+						},
+						{
+							Pos:     id.Pos(),
+							End:     id.End(),
+							NewText: []byte(new),
+						},
+						{
+							Pos:     call.Lparen + 1,
+							NewText: []byte("nil, "),
+						},
+					}
+					if len(conv.Args) == 1 {
+						arg := conv.Args[0]
+						// Determine if we have T(fmt.SprintX(...)). If so, delete the non-args
+						// that come before the right parenthesis. Leaving an
+						// extra comma here produces invalid code. (See
+						// golang/go#74709)
+						if arg.End() < conv.Rparen {
+							edits = append(edits, analysis.TextEdit{
+								Pos: arg.End(),
+								End: conv.Rparen,
+							})
+						}
+					}
+					pass.Report(analysis.Diagnostic{
+						Pos:     conv.Pos(),
+						End:     conv.End(),
+						Message: fmt.Sprintf("Replace []byte(fmt.%s...) with fmt.%s", old, new),
+						SuggestedFixes: []analysis.SuggestedFix{{
+							Message:   fmt.Sprintf("Replace []byte(fmt.%s...) with fmt.%s", old, new),
+							TextEdits: edits,
+						}},
+					})
+				}
+			}
+		}
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/forvar.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/forvar.go
new file mode 100644
index 00000000000000..76e3a8a73c2d27
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/forvar.go
@@ -0,0 +1,94 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"go/ast"
+	"go/token"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+)
+
+var ForVarAnalyzer = &analysis.Analyzer{
+	Name: "forvar",
+	Doc:  analysisinternal.MustExtractDoc(doc, "forvar"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+	},
+	Run: forvar,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#forvar",
+}
+
+// forvar offers to fix unnecessary copying of a for variable
+//
+//	for _, x := range foo {
+//		x := x // offer to remove this superfluous assignment
+//	}
+//
+// Prerequisites:
+// First statement in a range loop has to be  := 
+// where the two idents are the same,
+// and the ident is defined (:=) as a variable in the for statement.
+// (Note that this 'fix' does not work for three clause loops
+// because the Go specification says "The variable used by each subsequent iteration
+// is declared implicitly before executing the post statement and initialized to the
+// value of the previous iteration's variable at that moment.")
+func forvar(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	for curFile := range filesUsing(inspect, pass.TypesInfo, "go1.22") {
+		for curLoop := range curFile.Preorder((*ast.RangeStmt)(nil)) {
+			loop := curLoop.Node().(*ast.RangeStmt)
+			if loop.Tok != token.DEFINE {
+				continue
+			}
+			isLoopVarRedecl := func(assign *ast.AssignStmt) bool {
+				for i, lhs := range assign.Lhs {
+					if !(astutil.EqualSyntax(lhs, assign.Rhs[i]) &&
+						(astutil.EqualSyntax(lhs, loop.Key) || astutil.EqualSyntax(lhs, loop.Value))) {
+						return false
+					}
+				}
+				return true
+			}
+			// Have: for k, v := range x { stmts }
+			//
+			// Delete the prefix of stmts that are
+			// of the form k := k; v := v; k, v := k, v; v, k := v, k.
+			for _, stmt := range loop.Body.List {
+				if assign, ok := stmt.(*ast.AssignStmt); ok &&
+					assign.Tok == token.DEFINE &&
+					len(assign.Lhs) == len(assign.Rhs) &&
+					isLoopVarRedecl(assign) {
+
+					curStmt, _ := curLoop.FindNode(stmt)
+					edits := refactor.DeleteStmt(pass.Fset.File(stmt.Pos()), curStmt)
+					if len(edits) > 0 {
+						pass.Report(analysis.Diagnostic{
+							Pos:     stmt.Pos(),
+							End:     stmt.End(),
+							Message: "copying variable is unneeded",
+							SuggestedFixes: []analysis.SuggestedFix{{
+								Message:   "Remove unneeded redeclaration",
+								TextEdits: edits,
+							}},
+						})
+					}
+				} else {
+					break // stop at first other statement
+				}
+			}
+		}
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/maps.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/maps.go
new file mode 100644
index 00000000000000..3072cf6f5153a5
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/maps.go
@@ -0,0 +1,280 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+// This file defines modernizers that use the "maps" package.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typeparams"
+	"golang.org/x/tools/internal/typesinternal"
+)
+
+var MapsLoopAnalyzer = &analysis.Analyzer{
+	Name: "mapsloop",
+	Doc:  analysisinternal.MustExtractDoc(doc, "mapsloop"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+	},
+	Run: mapsloop,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#mapsloop",
+}
+
+// The mapsloop pass offers to simplify a loop of map insertions:
+//
+//	for k, v := range x {
+//		m[k] = v
+//	}
+//
+// by a call to go1.23's maps package. There are four variants, the
+// product of two axes: whether the source x is a map or an iter.Seq2,
+// and whether the destination m is a newly created map:
+//
+//	maps.Copy(m, x)		(x is map)
+//	maps.Insert(m, x)       (x is iter.Seq2)
+//	m = maps.Clone(x)       (x is a non-nil map, m is a new map)
+//	m = maps.Collect(x)     (x is iter.Seq2, m is a new map)
+//
+// A map is newly created if the preceding statement has one of these
+// forms, where M is a map type:
+//
+//	m = make(M)
+//	m = M{}
+func mapsloop(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	// Skip the analyzer in packages where its
+	// fixes would create an import cycle.
+	if within(pass, "maps", "bytes", "runtime") {
+		return nil, nil
+	}
+
+	info := pass.TypesInfo
+
+	// check is called for each statement of this form:
+	//   for k, v := range x { m[k] = v }
+	check := func(file *ast.File, curRange inspector.Cursor, assign *ast.AssignStmt, m, x ast.Expr) {
+
+		// Is x a map or iter.Seq2?
+		tx := types.Unalias(info.TypeOf(x))
+		var xmap bool
+		switch typeparams.CoreType(tx).(type) {
+		case *types.Map:
+			xmap = true
+
+		case *types.Signature:
+			k, v, ok := assignableToIterSeq2(tx)
+			if !ok {
+				return // a named isomer of Seq2
+			}
+			xmap = false
+
+			// Record in tx the unnamed map[K]V type
+			// derived from the yield function.
+			// This is the type of maps.Collect(x).
+			tx = types.NewMap(k, v)
+
+		default:
+			return // e.g. slice, channel (or no core type!)
+		}
+
+		// Is the preceding statement of the form
+		//    m = make(M) or M{}
+		// and can we replace its RHS with slices.{Clone,Collect}?
+		//
+		// Beware: if x may be nil, we cannot use Clone as it preserves nilness.
+		var mrhs ast.Expr // make(M) or M{}, or nil
+		if curPrev, ok := curRange.PrevSibling(); ok {
+			if assign, ok := curPrev.Node().(*ast.AssignStmt); ok &&
+				len(assign.Lhs) == 1 &&
+				len(assign.Rhs) == 1 &&
+				astutil.EqualSyntax(assign.Lhs[0], m) {
+
+				// Have: m = rhs; for k, v := range x { m[k] = v }
+				var newMap bool
+				rhs := assign.Rhs[0]
+				switch rhs := ast.Unparen(rhs).(type) {
+				case *ast.CallExpr:
+					if id, ok := ast.Unparen(rhs.Fun).(*ast.Ident); ok &&
+						info.Uses[id] == builtinMake {
+						// Have: m = make(...)
+						newMap = true
+					}
+				case *ast.CompositeLit:
+					if len(rhs.Elts) == 0 {
+						// Have m = M{}
+						newMap = true
+					}
+				}
+
+				// Take care not to change type of m's RHS expression.
+				if newMap {
+					trhs := info.TypeOf(rhs)
+
+					// Inv: tx is the type of maps.F(x)
+					// - maps.Clone(x) has the same type as x.
+					// - maps.Collect(x) returns an unnamed map type.
+
+					if assign.Tok == token.DEFINE {
+						// DEFINE (:=): we must not
+						// change the type of RHS.
+						if types.Identical(tx, trhs) {
+							mrhs = rhs
+						}
+					} else {
+						// ASSIGN (=): the types of LHS
+						// and RHS may differ in namedness.
+						if types.AssignableTo(tx, trhs) {
+							mrhs = rhs
+						}
+					}
+
+					// Temporarily disable the transformation to the
+					// (nil-preserving) maps.Clone until we can prove
+					// that x is non-nil. This is rarely possible,
+					// and may require control flow analysis
+					// (e.g. a dominating "if len(x)" check).
+					// See #71844.
+					if xmap {
+						mrhs = nil
+					}
+				}
+			}
+		}
+
+		// Choose function.
+		var funcName string
+		if mrhs != nil {
+			funcName = cond(xmap, "Clone", "Collect")
+		} else {
+			funcName = cond(xmap, "Copy", "Insert")
+		}
+
+		// Report diagnostic, and suggest fix.
+		rng := curRange.Node()
+		prefix, importEdits := refactor.AddImport(info, file, "maps", "maps", funcName, rng.Pos())
+		var (
+			newText    []byte
+			start, end token.Pos
+		)
+		if mrhs != nil {
+			// Replace assignment and loop with expression.
+			//
+			//   m = make(...)
+			//   for k, v := range x { /* comments */ m[k] = v }
+			//
+			//   ->
+			//
+			//   /* comments */
+			//   m = maps.Copy(x)
+			curPrev, _ := curRange.PrevSibling()
+			start, end = curPrev.Node().Pos(), rng.End()
+			newText = fmt.Appendf(nil, "%s%s = %s%s(%s)",
+				allComments(file, start, end),
+				astutil.Format(pass.Fset, m),
+				prefix,
+				funcName,
+				astutil.Format(pass.Fset, x))
+		} else {
+			// Replace loop with call statement.
+			//
+			//   for k, v := range x { /* comments */ m[k] = v }
+			//
+			//   ->
+			//
+			//   /* comments */
+			//   maps.Copy(m, x)
+			start, end = rng.Pos(), rng.End()
+			newText = fmt.Appendf(nil, "%s%s%s(%s, %s)",
+				allComments(file, start, end),
+				prefix,
+				funcName,
+				astutil.Format(pass.Fset, m),
+				astutil.Format(pass.Fset, x))
+		}
+		pass.Report(analysis.Diagnostic{
+			Pos:     assign.Lhs[0].Pos(),
+			End:     assign.Lhs[0].End(),
+			Message: "Replace m[k]=v loop with maps." + funcName,
+			SuggestedFixes: []analysis.SuggestedFix{{
+				Message: "Replace m[k]=v loop with maps." + funcName,
+				TextEdits: append(importEdits, []analysis.TextEdit{{
+					Pos:     start,
+					End:     end,
+					NewText: newText,
+				}}...),
+			}},
+		})
+
+	}
+
+	// Find all range loops around m[k] = v.
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	for curFile := range filesUsing(inspect, pass.TypesInfo, "go1.23") {
+		file := curFile.Node().(*ast.File)
+
+		for curRange := range curFile.Preorder((*ast.RangeStmt)(nil)) {
+			rng := curRange.Node().(*ast.RangeStmt)
+
+			if rng.Tok == token.DEFINE &&
+				rng.Key != nil &&
+				rng.Value != nil &&
+				isAssignBlock(rng.Body) {
+				// Have: for k, v := range x { lhs = rhs }
+
+				assign := rng.Body.List[0].(*ast.AssignStmt)
+				if index, ok := assign.Lhs[0].(*ast.IndexExpr); ok &&
+					astutil.EqualSyntax(rng.Key, index.Index) &&
+					astutil.EqualSyntax(rng.Value, assign.Rhs[0]) &&
+					is[*types.Map](typeparams.CoreType(info.TypeOf(index.X))) &&
+					types.Identical(info.TypeOf(index), info.TypeOf(rng.Value)) { // m[k], v
+
+					// Have: for k, v := range x { m[k] = v }
+					// where there is no implicit conversion.
+					check(file, curRange, assign, index.X, rng.X)
+				}
+			}
+		}
+	}
+	return nil, nil
+}
+
+// assignableToIterSeq2 reports whether t is assignable to
+// iter.Seq[K, V] and returns K and V if so.
+func assignableToIterSeq2(t types.Type) (k, v types.Type, ok bool) {
+	// The only named type assignable to iter.Seq2 is iter.Seq2.
+	if is[*types.Named](t) {
+		if !typesinternal.IsTypeNamed(t, "iter", "Seq2") {
+			return
+		}
+		t = t.Underlying()
+	}
+
+	if t, ok := t.(*types.Signature); ok {
+		// func(yield func(K, V) bool)?
+		if t.Params().Len() == 1 && t.Results().Len() == 0 {
+			if yield, ok := t.Params().At(0).Type().(*types.Signature); ok { // sic, no Underlying/CoreType
+				if yield.Params().Len() == 2 &&
+					yield.Results().Len() == 1 &&
+					types.Identical(yield.Results().At(0).Type(), builtinBool.Type()) {
+					return yield.Params().At(0).Type(), yield.Params().At(1).Type(), true
+				}
+			}
+		}
+	}
+	return
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/minmax.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/minmax.go
new file mode 100644
index 00000000000000..7ebf837375affd
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/minmax.go
@@ -0,0 +1,440 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typeparams"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var MinMaxAnalyzer = &analysis.Analyzer{
+	Name: "minmax",
+	Doc:  analysisinternal.MustExtractDoc(doc, "minmax"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: minmax,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#minmax",
+}
+
+// The minmax pass replaces if/else statements with calls to min or max,
+// and removes user-defined min/max functions that are equivalent to built-ins.
+//
+// If/else replacement patterns:
+//
+//  1. if a < b { x = a } else { x = b }        =>      x = min(a, b)
+//  2. x = a; if a < b { x = b }                =>      x = max(a, b)
+//
+// Pattern 1 requires that a is not NaN, and pattern 2 requires that b
+// is not Nan. Since this is hard to prove, we reject floating-point
+// numbers.
+//
+// Function removal:
+// User-defined min/max functions are suggested for removal if they may
+// be safely replaced by their built-in namesake.
+//
+// Variants:
+// - all four ordered comparisons
+// - "x := a" or "x = a" or "var x = a" in pattern 2
+// - "x < b" or "a < b" in pattern 2
+func minmax(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	// Check for user-defined min/max functions that can be removed
+	checkUserDefinedMinMax(pass)
+
+	// check is called for all statements of this form:
+	//   if a < b { lhs = rhs }
+	check := func(file *ast.File, curIfStmt inspector.Cursor, compare *ast.BinaryExpr) {
+		var (
+			ifStmt  = curIfStmt.Node().(*ast.IfStmt)
+			tassign = ifStmt.Body.List[0].(*ast.AssignStmt)
+			a       = compare.X
+			b       = compare.Y
+			lhs     = tassign.Lhs[0]
+			rhs     = tassign.Rhs[0]
+			sign    = isInequality(compare.Op)
+
+			// callArg formats a call argument, preserving comments from [start-end).
+			callArg = func(arg ast.Expr, start, end token.Pos) string {
+				comments := allComments(file, start, end)
+				return cond(arg == b, ", ", "") + // second argument needs a comma
+					cond(comments != "", "\n", "") + // comments need their own line
+					comments +
+					astutil.Format(pass.Fset, arg)
+			}
+		)
+
+		if fblock, ok := ifStmt.Else.(*ast.BlockStmt); ok && isAssignBlock(fblock) {
+			fassign := fblock.List[0].(*ast.AssignStmt)
+
+			// Have: if a < b { lhs = rhs } else { lhs2 = rhs2 }
+			lhs2 := fassign.Lhs[0]
+			rhs2 := fassign.Rhs[0]
+
+			// For pattern 1, check that:
+			// - lhs = lhs2
+			// - {rhs,rhs2} = {a,b}
+			if astutil.EqualSyntax(lhs, lhs2) {
+				if astutil.EqualSyntax(rhs, a) && astutil.EqualSyntax(rhs2, b) {
+					sign = +sign
+				} else if astutil.EqualSyntax(rhs2, a) && astutil.EqualSyntax(rhs, b) {
+					sign = -sign
+				} else {
+					return
+				}
+
+				sym := cond(sign < 0, "min", "max")
+
+				if !is[*types.Builtin](lookup(pass.TypesInfo, curIfStmt, sym)) {
+					return // min/max function is shadowed
+				}
+
+				// pattern 1
+				//
+				// TODO(adonovan): if lhs is declared "var lhs T" on preceding line,
+				// simplify the whole thing to "lhs := min(a, b)".
+				pass.Report(analysis.Diagnostic{
+					// Highlight the condition a < b.
+					Pos:     compare.Pos(),
+					End:     compare.End(),
+					Message: fmt.Sprintf("if/else statement can be modernized using %s", sym),
+					SuggestedFixes: []analysis.SuggestedFix{{
+						Message: fmt.Sprintf("Replace if statement with %s", sym),
+						TextEdits: []analysis.TextEdit{{
+							// Replace IfStmt with lhs = min(a, b).
+							Pos: ifStmt.Pos(),
+							End: ifStmt.End(),
+							NewText: fmt.Appendf(nil, "%s = %s(%s%s)",
+								astutil.Format(pass.Fset, lhs),
+								sym,
+								callArg(a, ifStmt.Pos(), ifStmt.Else.Pos()),
+								callArg(b, ifStmt.Else.Pos(), ifStmt.End()),
+							),
+						}},
+					}},
+				})
+			}
+
+		} else if prev, ok := curIfStmt.PrevSibling(); ok && isSimpleAssign(prev.Node()) && ifStmt.Else == nil {
+			fassign := prev.Node().(*ast.AssignStmt)
+
+			// Have: lhs0 = rhs0; if a < b { lhs = rhs }
+			//
+			// For pattern 2, check that
+			// - lhs = lhs0
+			// - {a,b} = {rhs,rhs0} or {rhs,lhs0}
+			//   The replacement must use rhs0 not lhs0 though.
+			//   For example, we accept this variant:
+			//     lhs = x; if lhs < y { lhs = y }   =>   lhs = min(x, y), not min(lhs, y)
+			//
+			// TODO(adonovan): accept "var lhs0 = rhs0" form too.
+			lhs0 := fassign.Lhs[0]
+			rhs0 := fassign.Rhs[0]
+
+			if astutil.EqualSyntax(lhs, lhs0) {
+				if astutil.EqualSyntax(rhs, a) && (astutil.EqualSyntax(rhs0, b) || astutil.EqualSyntax(lhs0, b)) {
+					sign = +sign
+				} else if (astutil.EqualSyntax(rhs0, a) || astutil.EqualSyntax(lhs0, a)) && astutil.EqualSyntax(rhs, b) {
+					sign = -sign
+				} else {
+					return
+				}
+				sym := cond(sign < 0, "min", "max")
+
+				if !is[*types.Builtin](lookup(pass.TypesInfo, curIfStmt, sym)) {
+					return // min/max function is shadowed
+				}
+
+				// Permit lhs0 to stand for rhs0 in the matching,
+				// but don't actually reduce to lhs0 = min(lhs0, rhs)
+				// since the "=" could be a ":=". Use min(rhs0, rhs).
+				if astutil.EqualSyntax(lhs0, a) {
+					a = rhs0
+				} else if astutil.EqualSyntax(lhs0, b) {
+					b = rhs0
+				}
+
+				// pattern 2
+				pass.Report(analysis.Diagnostic{
+					// Highlight the condition a < b.
+					Pos:     compare.Pos(),
+					End:     compare.End(),
+					Message: fmt.Sprintf("if statement can be modernized using %s", sym),
+					SuggestedFixes: []analysis.SuggestedFix{{
+						Message: fmt.Sprintf("Replace if/else with %s", sym),
+						TextEdits: []analysis.TextEdit{{
+							Pos: fassign.Pos(),
+							End: ifStmt.End(),
+							// Replace "x := a; if ... {}" with "x = min(...)", preserving comments.
+							NewText: fmt.Appendf(nil, "%s %s %s(%s%s)",
+								astutil.Format(pass.Fset, lhs),
+								fassign.Tok.String(),
+								sym,
+								callArg(a, fassign.Pos(), ifStmt.Pos()),
+								callArg(b, ifStmt.Pos(), ifStmt.End()),
+							),
+						}},
+					}},
+				})
+			}
+		}
+	}
+
+	// Find all "if a < b { lhs = rhs }" statements.
+	info := pass.TypesInfo
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	for curFile := range filesUsing(inspect, info, "go1.21") {
+		astFile := curFile.Node().(*ast.File)
+		for curIfStmt := range curFile.Preorder((*ast.IfStmt)(nil)) {
+			ifStmt := curIfStmt.Node().(*ast.IfStmt)
+
+			// Don't bother handling "if a < b { lhs = rhs }" when it appears
+			// as the "else" branch of another if-statement.
+			//    if cond { ... } else if a < b { lhs = rhs }
+			// (This case would require introducing another block
+			//    if cond { ... } else { if a < b { lhs = rhs } }
+			// and checking that there is no following "else".)
+			if astutil.IsChildOf(curIfStmt, edge.IfStmt_Else) {
+				continue
+			}
+
+			if compare, ok := ifStmt.Cond.(*ast.BinaryExpr); ok &&
+				ifStmt.Init == nil &&
+				isInequality(compare.Op) != 0 &&
+				isAssignBlock(ifStmt.Body) {
+				// a blank var has no type.
+				if tLHS := info.TypeOf(ifStmt.Body.List[0].(*ast.AssignStmt).Lhs[0]); tLHS != nil && !maybeNaN(tLHS) {
+					// Have: if a < b { lhs = rhs }
+					check(astFile, curIfStmt, compare)
+				}
+			}
+		}
+	}
+	return nil, nil
+}
+
+// allComments collects all the comments from start to end.
+func allComments(file *ast.File, start, end token.Pos) string {
+	var buf strings.Builder
+	for co := range astutil.Comments(file, start, end) {
+		_, _ = fmt.Fprintf(&buf, "%s\n", co.Text)
+	}
+	return buf.String()
+}
+
+// isInequality reports non-zero if tok is one of < <= => >:
+// +1 for > and -1 for <.
+func isInequality(tok token.Token) int {
+	switch tok {
+	case token.LEQ, token.LSS:
+		return -1
+	case token.GEQ, token.GTR:
+		return +1
+	}
+	return 0
+}
+
+// isAssignBlock reports whether b is a block of the form { lhs = rhs }.
+func isAssignBlock(b *ast.BlockStmt) bool {
+	if len(b.List) != 1 {
+		return false
+	}
+	// Inv: the sole statement cannot be { lhs := rhs }.
+	return isSimpleAssign(b.List[0])
+}
+
+// isSimpleAssign reports whether n has the form "lhs = rhs" or "lhs := rhs".
+func isSimpleAssign(n ast.Node) bool {
+	assign, ok := n.(*ast.AssignStmt)
+	return ok &&
+		(assign.Tok == token.ASSIGN || assign.Tok == token.DEFINE) &&
+		len(assign.Lhs) == 1 &&
+		len(assign.Rhs) == 1
+}
+
+// maybeNaN reports whether t is (or may be) a floating-point type.
+func maybeNaN(t types.Type) bool {
+	// For now, we rely on core types.
+	// TODO(adonovan): In the post-core-types future,
+	// follow the approach of types.Checker.applyTypeFunc.
+	t = typeparams.CoreType(t)
+	if t == nil {
+		return true // fail safe
+	}
+	if basic, ok := t.(*types.Basic); ok && basic.Info()&types.IsFloat != 0 {
+		return true
+	}
+	return false
+}
+
+// checkUserDefinedMinMax looks for user-defined min/max functions that are
+// equivalent to the built-in functions and suggests removing them.
+func checkUserDefinedMinMax(pass *analysis.Pass) {
+	index := pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+
+	// Look up min and max functions by name in package scope
+	for _, funcName := range []string{"min", "max"} {
+		if fn, ok := pass.Pkg.Scope().Lookup(funcName).(*types.Func); ok {
+			// Use typeindex to get the FuncDecl directly
+			if def, ok := index.Def(fn); ok {
+				decl := def.Parent().Node().(*ast.FuncDecl)
+				// Check if this function matches the built-in min/max signature and behavior
+				if canUseBuiltinMinMax(fn, decl.Body) {
+					// Expand to include leading doc comment
+					pos := decl.Pos()
+					if docs := astutil.DocComment(decl); docs != nil {
+						pos = docs.Pos()
+					}
+
+					pass.Report(analysis.Diagnostic{
+						Pos:     decl.Pos(),
+						End:     decl.End(),
+						Message: fmt.Sprintf("user-defined %s function is equivalent to built-in %s and can be removed", funcName, funcName),
+						SuggestedFixes: []analysis.SuggestedFix{{
+							Message: fmt.Sprintf("Remove user-defined %s function", funcName),
+							TextEdits: []analysis.TextEdit{{
+								Pos: pos,
+								End: decl.End(),
+							}},
+						}},
+					})
+				}
+			}
+		}
+	}
+}
+
+// canUseBuiltinMinMax reports whether it is safe to replace a call
+// to this min or max function by its built-in namesake.
+func canUseBuiltinMinMax(fn *types.Func, body *ast.BlockStmt) bool {
+	sig := fn.Type().(*types.Signature)
+
+	// Only consider the most common case: exactly 2 parameters
+	if sig.Params().Len() != 2 {
+		return false
+	}
+
+	// Check if any parameter might be floating-point
+	for param := range sig.Params().Variables() {
+		if maybeNaN(param.Type()) {
+			return false // Don't suggest removal for float types due to NaN handling
+		}
+	}
+
+	// Must have exactly one return value
+	if sig.Results().Len() != 1 {
+		return false
+	}
+
+	// Check that the function body implements the expected min/max logic
+	if body == nil {
+		return false
+	}
+
+	return hasMinMaxLogic(body, fn.Name())
+}
+
+// hasMinMaxLogic checks if the function body implements simple min/max logic.
+func hasMinMaxLogic(body *ast.BlockStmt, funcName string) bool {
+	// Pattern 1: Single if/else statement
+	if len(body.List) == 1 {
+		if ifStmt, ok := body.List[0].(*ast.IfStmt); ok {
+			// Get the "false" result from the else block
+			if elseBlock, ok := ifStmt.Else.(*ast.BlockStmt); ok && len(elseBlock.List) == 1 {
+				if elseRet, ok := elseBlock.List[0].(*ast.ReturnStmt); ok && len(elseRet.Results) == 1 {
+					return checkMinMaxPattern(ifStmt, elseRet.Results[0], funcName)
+				}
+			}
+		}
+	}
+
+	// Pattern 2: if statement followed by return
+	if len(body.List) == 2 {
+		if ifStmt, ok := body.List[0].(*ast.IfStmt); ok && ifStmt.Else == nil {
+			if retStmt, ok := body.List[1].(*ast.ReturnStmt); ok && len(retStmt.Results) == 1 {
+				return checkMinMaxPattern(ifStmt, retStmt.Results[0], funcName)
+			}
+		}
+	}
+
+	return false
+}
+
+// checkMinMaxPattern checks if an if statement implements min/max logic.
+// ifStmt: the if statement to check
+// falseResult: the expression returned when the condition is false
+// funcName: "min" or "max"
+func checkMinMaxPattern(ifStmt *ast.IfStmt, falseResult ast.Expr, funcName string) bool {
+	// Must have condition with comparison
+	cmp, ok := ifStmt.Cond.(*ast.BinaryExpr)
+	if !ok {
+		return false
+	}
+
+	// Check if then branch returns one of the compared values
+	if len(ifStmt.Body.List) != 1 {
+		return false
+	}
+
+	thenRet, ok := ifStmt.Body.List[0].(*ast.ReturnStmt)
+	if !ok || len(thenRet.Results) != 1 {
+		return false
+	}
+
+	// Use the same logic as the existing minmax analyzer
+	sign := isInequality(cmp.Op)
+	if sign == 0 {
+		return false // Not a comparison operator
+	}
+
+	t := thenRet.Results[0] // "true" result
+	f := falseResult        // "false" result
+	x := cmp.X              // left operand
+	y := cmp.Y              // right operand
+
+	// Check operand order and adjust sign accordingly
+	if astutil.EqualSyntax(t, x) && astutil.EqualSyntax(f, y) {
+		sign = +sign
+	} else if astutil.EqualSyntax(t, y) && astutil.EqualSyntax(f, x) {
+		sign = -sign
+	} else {
+		return false
+	}
+
+	// Check if the sign matches the function name
+	return cond(sign < 0, "min", "max") == funcName
+}
+
+// -- utils --
+
+func is[T any](x any) bool {
+	_, ok := x.(T)
+	return ok
+}
+
+func cond[T any](cond bool, t, f T) T {
+	if cond {
+		return t
+	} else {
+		return f
+	}
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/modernize.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/modernize.go
new file mode 100644
index 00000000000000..df23fc23c8e2f9
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/modernize.go
@@ -0,0 +1,162 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	_ "embed"
+	"go/ast"
+	"go/constant"
+	"go/format"
+	"go/token"
+	"go/types"
+	"iter"
+	"regexp"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/moreiters"
+	"golang.org/x/tools/internal/packagepath"
+	"golang.org/x/tools/internal/stdlib"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/versions"
+)
+
+//go:embed doc.go
+var doc string
+
+// Suite lists all modernize analyzers.
+var Suite = []*analysis.Analyzer{
+	AnyAnalyzer,
+	// AppendClippedAnalyzer, // not nil-preserving!
+	BLoopAnalyzer,
+	FmtAppendfAnalyzer,
+	ForVarAnalyzer,
+	MapsLoopAnalyzer,
+	MinMaxAnalyzer,
+	NewExprAnalyzer,
+	OmitZeroAnalyzer,
+	plusBuildAnalyzer,
+	RangeIntAnalyzer,
+	ReflectTypeForAnalyzer,
+	SlicesContainsAnalyzer,
+	// SlicesDeleteAnalyzer, // not nil-preserving!
+	SlicesSortAnalyzer,
+	stditeratorsAnalyzer,
+	StringsCutPrefixAnalyzer,
+	StringsSeqAnalyzer,
+	StringsBuilderAnalyzer,
+	TestingContextAnalyzer,
+	WaitGroupAnalyzer,
+}
+
+// -- helpers --
+
+// skipGenerated decorates pass.Report to suppress diagnostics in generated files.
+func skipGenerated(pass *analysis.Pass) {
+	report := pass.Report
+	pass.Report = func(diag analysis.Diagnostic) {
+		generated := pass.ResultOf[generated.Analyzer].(*generated.Result)
+		if generated.IsGenerated(diag.Pos) {
+			return // skip
+		}
+		report(diag)
+	}
+}
+
+// formatExprs formats a comma-separated list of expressions.
+func formatExprs(fset *token.FileSet, exprs []ast.Expr) string {
+	var buf strings.Builder
+	for i, e := range exprs {
+		if i > 0 {
+			buf.WriteString(",  ")
+		}
+		format.Node(&buf, fset, e) // ignore errors
+	}
+	return buf.String()
+}
+
+// isZeroIntLiteral reports whether e is an integer whose value is 0.
+func isZeroIntLiteral(info *types.Info, e ast.Expr) bool {
+	return isIntLiteral(info, e, 0)
+}
+
+// isIntLiteral reports whether e is an integer with given value.
+func isIntLiteral(info *types.Info, e ast.Expr, n int64) bool {
+	return info.Types[e].Value == constant.MakeInt64(n)
+}
+
+// filesUsing returns a cursor for each *ast.File in the inspector
+// that uses at least the specified version of Go (e.g. "go1.24").
+//
+// TODO(adonovan): opt: eliminate this function, instead following the
+// approach of [fmtappendf], which uses typeindex and [fileUses].
+// See "Tip" at [fileUses] for motivation.
+func filesUsing(inspect *inspector.Inspector, info *types.Info, version string) iter.Seq[inspector.Cursor] {
+	return func(yield func(inspector.Cursor) bool) {
+		for curFile := range inspect.Root().Children() {
+			file := curFile.Node().(*ast.File)
+			if !versions.Before(info.FileVersions[file], version) && !yield(curFile) {
+				break
+			}
+		}
+	}
+}
+
+// fileUses reports whether the specified file uses at least the
+// specified version of Go (e.g. "go1.24").
+//
+// Tip: we recommend using this check "late", just before calling
+// pass.Report, rather than "early" (when entering each ast.File, or
+// each candidate node of interest, during the traversal), because the
+// operation is not free, yet is not a highly selective filter: the
+// fraction of files that pass most version checks is high and
+// increases over time.
+func fileUses(info *types.Info, file *ast.File, version string) bool {
+	return !versions.Before(info.FileVersions[file], version)
+}
+
+// within reports whether the current pass is analyzing one of the
+// specified standard packages or their dependencies.
+func within(pass *analysis.Pass, pkgs ...string) bool {
+	path := pass.Pkg.Path()
+	return packagepath.IsStdPackage(path) &&
+		moreiters.Contains(stdlib.Dependencies(pkgs...), path)
+}
+
+// unparenEnclosing removes enclosing parens from cur in
+// preparation for a call to [Cursor.ParentEdge].
+func unparenEnclosing(cur inspector.Cursor) inspector.Cursor {
+	for astutil.IsChildOf(cur, edge.ParenExpr_X) {
+		cur = cur.Parent()
+	}
+	return cur
+}
+
+var (
+	builtinAny     = types.Universe.Lookup("any")
+	builtinAppend  = types.Universe.Lookup("append")
+	builtinBool    = types.Universe.Lookup("bool")
+	builtinInt     = types.Universe.Lookup("int")
+	builtinFalse   = types.Universe.Lookup("false")
+	builtinLen     = types.Universe.Lookup("len")
+	builtinMake    = types.Universe.Lookup("make")
+	builtinNew     = types.Universe.Lookup("new")
+	builtinNil     = types.Universe.Lookup("nil")
+	builtinString  = types.Universe.Lookup("string")
+	builtinTrue    = types.Universe.Lookup("true")
+	byteSliceType  = types.NewSlice(types.Typ[types.Byte])
+	omitemptyRegex = regexp.MustCompile(`(?:^json| json):"[^"]*(,omitempty)(?:"|,[^"]*")\s?`)
+)
+
+// lookup returns the symbol denoted by name at the position of the cursor.
+func lookup(info *types.Info, cur inspector.Cursor, name string) types.Object {
+	scope := typesinternal.EnclosingScope(info, cur)
+	_, obj := scope.LookupParent(name, cur.Node().Pos())
+	return obj
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/newexpr.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/newexpr.go
new file mode 100644
index 00000000000000..b8893244d51390
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/newexpr.go
@@ -0,0 +1,208 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	_ "embed"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"strings"
+
+	"fmt"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/astutil"
+)
+
+var NewExprAnalyzer = &analysis.Analyzer{
+	Name:      "newexpr",
+	Doc:       analysisinternal.MustExtractDoc(doc, "newexpr"),
+	URL:       "https://pkg.go.dev/golang.org/x/tools/gopls/internal/analysis/modernize#newexpr",
+	Requires:  []*analysis.Analyzer{inspect.Analyzer},
+	Run:       run,
+	FactTypes: []analysis.Fact{&newLike{}},
+}
+
+func run(pass *analysis.Pass) (any, error) {
+	var (
+		inspect = pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		info    = pass.TypesInfo
+	)
+
+	// Detect functions that are new-like, i.e. have the form:
+	//
+	//	func f(x T) *T { return &x }
+	//
+	// meaning that it is equivalent to new(x), if x has type T.
+	for curFuncDecl := range inspect.Root().Preorder((*ast.FuncDecl)(nil)) {
+		decl := curFuncDecl.Node().(*ast.FuncDecl)
+		fn := info.Defs[decl.Name].(*types.Func)
+		if decl.Body != nil && len(decl.Body.List) == 1 {
+			if ret, ok := decl.Body.List[0].(*ast.ReturnStmt); ok && len(ret.Results) == 1 {
+				if unary, ok := ret.Results[0].(*ast.UnaryExpr); ok && unary.Op == token.AND {
+					if id, ok := unary.X.(*ast.Ident); ok {
+						if v, ok := info.Uses[id].(*types.Var); ok {
+							sig := fn.Signature()
+							if sig.Results().Len() == 1 &&
+								is[*types.Pointer](sig.Results().At(0).Type()) && // => no iface conversion
+								sig.Params().Len() == 1 &&
+								sig.Params().At(0) == v {
+
+								// Export a fact for each one.
+								pass.ExportObjectFact(fn, &newLike{})
+
+								// Check file version.
+								file := astutil.EnclosingFile(curFuncDecl)
+								if !fileUses(info, file, "go1.26") {
+									continue // new(expr) not available in this file
+								}
+
+								var edits []analysis.TextEdit
+
+								// If 'new' is not shadowed, replace func body: &x -> new(x).
+								// This makes it safely and cleanly inlinable.
+								curRet, _ := curFuncDecl.FindNode(ret)
+								if lookup(info, curRet, "new") == builtinNew {
+									edits = []analysis.TextEdit{
+										// return    &x
+										//        ---- -
+										// return new(x)
+										{
+											Pos:     unary.OpPos,
+											End:     unary.OpPos + token.Pos(len("&")),
+											NewText: []byte("new("),
+										},
+										{
+											Pos:     unary.X.End(),
+											End:     unary.X.End(),
+											NewText: []byte(")"),
+										},
+									}
+								}
+
+								// Disabled until we resolve https://go.dev/issue/75726
+								// (Go version skew between caller and callee in inliner.)
+								// TODO(adonovan): fix and reenable.
+								//
+								// Also, restore these lines to our section of doc.go:
+								// 	//go:fix inline
+								//	...
+								// 	(The directive comment causes the inline analyzer to suggest
+								// 	that calls to such functions are inlined.)
+								if false {
+									// Add a //go:fix inline annotation, if not already present.
+									// TODO(adonovan): use ast.ParseDirective when go1.26 is assured.
+									if !strings.Contains(decl.Doc.Text(), "go:fix inline") {
+										edits = append(edits, analysis.TextEdit{
+											Pos:     decl.Pos(),
+											End:     decl.Pos(),
+											NewText: []byte("//go:fix inline\n"),
+										})
+									}
+								}
+
+								if len(edits) > 0 {
+									pass.Report(analysis.Diagnostic{
+										Pos:     decl.Name.Pos(),
+										End:     decl.Name.End(),
+										Message: fmt.Sprintf("%s can be an inlinable wrapper around new(expr)", decl.Name),
+										SuggestedFixes: []analysis.SuggestedFix{
+											{
+												Message:   "Make %s an inlinable wrapper around new(expr)",
+												TextEdits: edits,
+											},
+										},
+									})
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+
+	// Report and transform calls, when safe.
+	// In effect, this is inlining the new-like function
+	// even before we have marked the callee with //go:fix inline.
+	for curCall := range inspect.Root().Preorder((*ast.CallExpr)(nil)) {
+		call := curCall.Node().(*ast.CallExpr)
+		var fact newLike
+		if fn, ok := typeutil.Callee(info, call).(*types.Func); ok &&
+			pass.ImportObjectFact(fn, &fact) {
+
+			// Check file version.
+			file := astutil.EnclosingFile(curCall)
+			if !fileUses(info, file, "go1.26") {
+				continue // new(expr) not available in this file
+			}
+
+			// Check new is not shadowed.
+			if lookup(info, curCall, "new") != builtinNew {
+				continue
+			}
+
+			// The return type *T must exactly match the argument type T.
+			// (We formulate it this way--not in terms of the parameter
+			// type--to support generics.)
+			var targ types.Type
+			{
+				arg := call.Args[0]
+				tvarg := info.Types[arg]
+
+				// Constants: we must work around the type checker
+				// bug that causes info.Types to wrongly report the
+				// "typed" type for an untyped constant.
+				// (See "historical reasons" in issue go.dev/issue/70638.)
+				//
+				// We don't have a reliable way to do this but we can attempt
+				// to re-typecheck the constant expression on its own, in
+				// the original lexical environment but not as a part of some
+				// larger expression that implies a conversion to some "typed" type.
+				// (For the genesis of this idea see (*state).arguments
+				// in ../../../../internal/refactor/inline/inline.go.)
+				if tvarg.Value != nil {
+					info2 := &types.Info{Types: make(map[ast.Expr]types.TypeAndValue)}
+					if err := types.CheckExpr(token.NewFileSet(), pass.Pkg, token.NoPos, arg, info2); err != nil {
+						continue // unexpected error
+					}
+					tvarg = info2.Types[arg]
+				}
+
+				targ = types.Default(tvarg.Type)
+			}
+			if !types.Identical(types.NewPointer(targ), info.TypeOf(call)) {
+				continue
+			}
+
+			pass.Report(analysis.Diagnostic{
+				Pos:     call.Pos(),
+				End:     call.End(),
+				Message: fmt.Sprintf("call of %s(x) can be simplified to new(x)", fn.Name()),
+				SuggestedFixes: []analysis.SuggestedFix{{
+					Message: fmt.Sprintf("Simplify %s(x) to new(x)", fn.Name()),
+					TextEdits: []analysis.TextEdit{{
+						Pos:     call.Fun.Pos(),
+						End:     call.Fun.End(),
+						NewText: []byte("new"),
+					}},
+				}},
+			})
+		}
+	}
+
+	return nil, nil
+}
+
+// A newLike fact records that its associated function is "new-like".
+type newLike struct{}
+
+func (*newLike) AFact()         {}
+func (*newLike) String() string { return "newlike" }
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/omitzero.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/omitzero.go
new file mode 100644
index 00000000000000..bd309cf9d598e2
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/omitzero.go
@@ -0,0 +1,119 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"go/ast"
+	"go/types"
+	"reflect"
+	"strconv"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	"golang.org/x/tools/internal/astutil"
+)
+
+var OmitZeroAnalyzer = &analysis.Analyzer{
+	Name: "omitzero",
+	Doc:  analysisinternal.MustExtractDoc(doc, "omitzero"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+	},
+	Run: omitzero,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#omitzero",
+}
+
+func checkOmitEmptyField(pass *analysis.Pass, info *types.Info, curField *ast.Field) {
+	typ := info.TypeOf(curField.Type)
+	_, ok := typ.Underlying().(*types.Struct)
+	if !ok {
+		// Not a struct
+		return
+	}
+	tag := curField.Tag
+	if tag == nil {
+		// No tag to check
+		return
+	}
+	// The omitempty tag may be used by other packages besides json, but we should only modify its use with json
+	tagconv, _ := strconv.Unquote(tag.Value)
+	match := omitemptyRegex.FindStringSubmatchIndex(tagconv)
+	if match == nil {
+		// No omitempty in json tag
+		return
+	}
+	omitEmptyPos, omitEmptyEnd, err := astutil.RangeInStringLiteral(curField.Tag, match[2], match[3])
+	if err != nil {
+		return
+	}
+	removePos, removeEnd := omitEmptyPos, omitEmptyEnd
+
+	jsonTag := reflect.StructTag(tagconv).Get("json")
+	if jsonTag == ",omitempty" {
+		// Remove the entire struct tag if json is the only package used
+		if match[1]-match[0] == len(tagconv) {
+			removePos = curField.Tag.Pos()
+			removeEnd = curField.Tag.End()
+		} else {
+			// Remove the json tag if omitempty is the only field
+			removePos, err = astutil.PosInStringLiteral(curField.Tag, match[0])
+			if err != nil {
+				return
+			}
+			removeEnd, err = astutil.PosInStringLiteral(curField.Tag, match[1])
+			if err != nil {
+				return
+			}
+		}
+	}
+	pass.Report(analysis.Diagnostic{
+		Pos:     curField.Tag.Pos(),
+		End:     curField.Tag.End(),
+		Message: "Omitempty has no effect on nested struct fields",
+		SuggestedFixes: []analysis.SuggestedFix{
+			{
+				Message: "Remove redundant omitempty tag",
+				TextEdits: []analysis.TextEdit{
+					{
+						Pos: removePos,
+						End: removeEnd,
+					},
+				},
+			},
+			{
+				Message: "Replace omitempty with omitzero (behavior change)",
+				TextEdits: []analysis.TextEdit{
+					{
+						Pos:     omitEmptyPos,
+						End:     omitEmptyEnd,
+						NewText: []byte(",omitzero"),
+					},
+				},
+			},
+		}})
+}
+
+// The omitzero pass searches for instances of "omitempty" in a json field tag on a
+// struct. Since "omitempty" does not have any effect when applied to a struct field,
+// it suggests either deleting "omitempty" or replacing it with "omitzero", which
+// correctly excludes structs from a json encoding.
+func omitzero(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	info := pass.TypesInfo
+	for curFile := range filesUsing(inspect, info, "go1.24") {
+		for curStruct := range curFile.Preorder((*ast.StructType)(nil)) {
+			for _, curField := range curStruct.Node().(*ast.StructType).Fields.List {
+				checkOmitEmptyField(pass, info, curField)
+			}
+		}
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/plusbuild.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/plusbuild.go
new file mode 100644
index 00000000000000..e8af8074ff6c38
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/plusbuild.go
@@ -0,0 +1,83 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"go/ast"
+	"go/parser"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/goplsexport"
+)
+
+var plusBuildAnalyzer = &analysis.Analyzer{
+	Name: "plusbuild",
+	Doc:  analysisinternal.MustExtractDoc(doc, "plusbuild"),
+	URL:  "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#plusbuild",
+	Run:  plusbuild,
+}
+
+func init() {
+	// Export to gopls until this is a published modernizer.
+	goplsexport.PlusBuildModernizer = plusBuildAnalyzer
+}
+
+func plusbuild(pass *analysis.Pass) (any, error) {
+	check := func(f *ast.File) {
+		if !fileUses(pass.TypesInfo, f, "go1.18") {
+			return
+		}
+
+		// When gofmt sees a +build comment, it adds a
+		// preceding equivalent //go:build directive, so in
+		// formatted files we can assume that a +build line is
+		// part of a comment group that starts with a
+		// //go:build line and is followed by a blank line.
+		//
+		// While we cannot delete comments from an AST and
+		// expect consistent output in general, this specific
+		// case--deleting only some lines from a comment
+		// block--does format correctly.
+		for _, g := range f.Comments {
+			sawGoBuild := false
+			for _, c := range g.List {
+				if sawGoBuild && strings.HasPrefix(c.Text, "// +build ") {
+					pass.Report(analysis.Diagnostic{
+						Pos:     c.Pos(),
+						End:     c.End(),
+						Message: "+build line is no longer needed",
+						SuggestedFixes: []analysis.SuggestedFix{{
+							Message: "Remove obsolete +build line",
+							TextEdits: []analysis.TextEdit{{
+								Pos: c.Pos(),
+								End: c.End(),
+							}},
+						}},
+					})
+					break
+				}
+				if strings.HasPrefix(c.Text, "//go:build ") {
+					sawGoBuild = true
+				}
+			}
+		}
+	}
+
+	for _, f := range pass.Files {
+		check(f)
+	}
+	for _, name := range pass.IgnoredFiles {
+		if strings.HasSuffix(name, ".go") {
+			f, err := parser.ParseFile(pass.Fset, name, nil, parser.ParseComments|parser.SkipObjectResolution)
+			if err != nil {
+				continue // parse error: ignore
+			}
+			check(f)
+		}
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/rangeint.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/rangeint.go
new file mode 100644
index 00000000000000..adc840f11d5886
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/rangeint.go
@@ -0,0 +1,310 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var RangeIntAnalyzer = &analysis.Analyzer{
+	Name: "rangeint",
+	Doc:  analysisinternal.MustExtractDoc(doc, "rangeint"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: rangeint,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#rangeint",
+}
+
+// rangeint offers a fix to replace a 3-clause 'for' loop:
+//
+//	for i := 0; i < limit; i++ {}
+//
+// by a range loop with an integer operand:
+//
+//	for i := range limit {}
+//
+// Variants:
+//   - The ':=' may be replaced by '='.
+//   - The fix may remove "i :=" if it would become unused.
+//
+// Restrictions:
+//   - The variable i must not be assigned or address-taken within the
+//     loop, because a "for range int" loop does not respect assignments
+//     to the loop index.
+//   - The limit must not be b.N, to avoid redundancy with bloop's fixes.
+//
+// Caveats:
+//
+// The fix causes the limit expression to be evaluated exactly once,
+// instead of once per iteration. So, to avoid changing the
+// cardinality of side effects, the limit expression must not involve
+// function calls (e.g. seq.Len()) or channel receives. Moreover, the
+// value of the limit expression must be loop invariant, which in
+// practice means it must take one of the following forms:
+//
+//   - a local variable that is assigned only once and not address-taken;
+//   - a constant; or
+//   - len(s), where s has the above properties.
+func rangeint(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	info := pass.TypesInfo
+
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	typeindex := pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+
+	for curFile := range filesUsing(inspect, info, "go1.22") {
+	nextLoop:
+		for curLoop := range curFile.Preorder((*ast.ForStmt)(nil)) {
+			loop := curLoop.Node().(*ast.ForStmt)
+			if init, ok := loop.Init.(*ast.AssignStmt); ok &&
+				isSimpleAssign(init) &&
+				is[*ast.Ident](init.Lhs[0]) &&
+				isZeroIntLiteral(info, init.Rhs[0]) {
+				// Have: for i = 0; ... (or i := 0)
+				index := init.Lhs[0].(*ast.Ident)
+
+				if compare, ok := loop.Cond.(*ast.BinaryExpr); ok &&
+					compare.Op == token.LSS &&
+					astutil.EqualSyntax(compare.X, init.Lhs[0]) {
+					// Have: for i = 0; i < limit; ... {}
+
+					limit := compare.Y
+
+					// If limit is "len(slice)", simplify it to "slice".
+					//
+					// (Don't replace "for i := 0; i < len(map); i++"
+					// with "for range m" because it's too hard to prove
+					// that len(m) is loop-invariant).
+					if call, ok := limit.(*ast.CallExpr); ok &&
+						typeutil.Callee(info, call) == builtinLen &&
+						is[*types.Slice](info.TypeOf(call.Args[0]).Underlying()) {
+						limit = call.Args[0]
+					}
+
+					// Check the form of limit: must be a constant,
+					// or a local var that is not assigned or address-taken.
+					limitOK := false
+					if info.Types[limit].Value != nil {
+						limitOK = true // constant
+					} else if id, ok := limit.(*ast.Ident); ok {
+						if v, ok := info.Uses[id].(*types.Var); ok &&
+							!(v.Exported() && typesinternal.IsPackageLevel(v)) {
+							// limit is a local or unexported global var.
+							// (An exported global may have uses we can't see.)
+							for cur := range typeindex.Uses(v) {
+								if isScalarLvalue(info, cur) {
+									// Limit var is assigned or address-taken.
+									continue nextLoop
+								}
+							}
+							limitOK = true
+						}
+					}
+					if !limitOK {
+						continue nextLoop
+					}
+
+					if inc, ok := loop.Post.(*ast.IncDecStmt); ok &&
+						inc.Tok == token.INC &&
+						astutil.EqualSyntax(compare.X, inc.X) {
+						// Have: for i = 0; i < limit; i++ {}
+
+						// Find references to i within the loop body.
+						v := info.ObjectOf(index).(*types.Var)
+						// TODO(adonovan): use go1.25 v.Kind() == types.PackageVar
+						if typesinternal.IsPackageLevel(v) {
+							continue nextLoop
+						}
+						used := false
+						for curId := range curLoop.Child(loop.Body).Preorder((*ast.Ident)(nil)) {
+							id := curId.Node().(*ast.Ident)
+							if info.Uses[id] == v {
+								used = true
+
+								// Reject if any is an l-value (assigned or address-taken):
+								// a "for range int" loop does not respect assignments to
+								// the loop variable.
+								if isScalarLvalue(info, curId) {
+									continue nextLoop
+								}
+							}
+						}
+
+						// If i is no longer used, delete "i := ".
+						var edits []analysis.TextEdit
+						if !used && init.Tok == token.DEFINE {
+							edits = append(edits, analysis.TextEdit{
+								Pos: index.Pos(),
+								End: init.Rhs[0].Pos(),
+							})
+						}
+
+						// If i is used after the loop,
+						// don't offer a fix, as a range loop
+						// leaves i with a different final value (limit-1).
+						if init.Tok == token.ASSIGN {
+							for curId := range curLoop.Parent().Preorder((*ast.Ident)(nil)) {
+								id := curId.Node().(*ast.Ident)
+								if info.Uses[id] == v {
+									// Is i used after loop?
+									if id.Pos() > loop.End() {
+										continue nextLoop
+									}
+									// Is i used within a defer statement
+									// that is within the scope of i?
+									//     var i int
+									//     defer func() { print(i)}
+									//     for i = ... { ... }
+									for curDefer := range curId.Enclosing((*ast.DeferStmt)(nil)) {
+										if curDefer.Node().Pos() > v.Pos() {
+											continue nextLoop
+										}
+									}
+								}
+							}
+						}
+
+						// If limit is len(slice),
+						// simplify "range len(slice)" to "range slice".
+						if call, ok := limit.(*ast.CallExpr); ok &&
+							typeutil.Callee(info, call) == builtinLen &&
+							is[*types.Slice](info.TypeOf(call.Args[0]).Underlying()) {
+							limit = call.Args[0]
+						}
+
+						// If the limit is a untyped constant of non-integer type,
+						// such as "const limit = 1e3", its effective type may
+						// differ between the two forms.
+						// In a for loop, it must be comparable with int i,
+						//    for i := 0; i < limit; i++
+						// but in a range loop it would become a float,
+						//    for i := range limit {}
+						// which is a type error. We need to convert it to int
+						// in this case.
+						//
+						// Unfortunately go/types discards the untyped type
+						// (but see Untyped in golang/go#70638) so we must
+						// re-type check the expression to detect this case.
+						var beforeLimit, afterLimit string
+						if v := info.Types[limit].Value; v != nil {
+							tVar := info.TypeOf(init.Rhs[0])
+							file := curFile.Node().(*ast.File)
+							// TODO(mkalil): use a types.Qualifier that respects the existing
+							// imports of this file that are visible (not shadowed) at the current position.
+							qual := typesinternal.FileQualifier(file, pass.Pkg)
+							beforeLimit, afterLimit = fmt.Sprintf("%s(", types.TypeString(tVar, qual)), ")"
+							info2 := &types.Info{Types: make(map[ast.Expr]types.TypeAndValue)}
+							if types.CheckExpr(pass.Fset, pass.Pkg, limit.Pos(), limit, info2) == nil {
+								tLimit := types.Default(info2.TypeOf(limit))
+								if types.AssignableTo(tLimit, tVar) {
+									beforeLimit, afterLimit = "", ""
+								}
+							}
+						}
+
+						pass.Report(analysis.Diagnostic{
+							Pos:     init.Pos(),
+							End:     inc.End(),
+							Message: "for loop can be modernized using range over int",
+							SuggestedFixes: []analysis.SuggestedFix{{
+								Message: fmt.Sprintf("Replace for loop with range %s",
+									astutil.Format(pass.Fset, limit)),
+								TextEdits: append(edits, []analysis.TextEdit{
+									// for i := 0; i < limit; i++ {}
+									//     -----              ---
+									//          -------
+									// for i := range  limit      {}
+
+									// Delete init.
+									{
+										Pos:     init.Rhs[0].Pos(),
+										End:     limit.Pos(),
+										NewText: []byte("range "),
+									},
+									// Add "int(" before limit, if needed.
+									{
+										Pos:     limit.Pos(),
+										End:     limit.Pos(),
+										NewText: []byte(beforeLimit),
+									},
+									// Delete inc.
+									{
+										Pos: limit.End(),
+										End: inc.End(),
+									},
+									// Add ")" after limit, if needed.
+									{
+										Pos:     limit.End(),
+										End:     limit.End(),
+										NewText: []byte(afterLimit),
+									},
+								}...),
+							}},
+						})
+					}
+				}
+			}
+		}
+	}
+	return nil, nil
+}
+
+// isScalarLvalue reports whether the specified identifier is
+// address-taken or appears on the left side of an assignment.
+//
+// This function is valid only for scalars (x = ...),
+// not for aggregates (x.a[i] = ...)
+func isScalarLvalue(info *types.Info, curId inspector.Cursor) bool {
+	// Unfortunately we can't simply use info.Types[e].Assignable()
+	// as it is always true for a variable even when that variable is
+	// used only as an r-value. So we must inspect enclosing syntax.
+
+	cur := curId
+
+	// Strip enclosing parens.
+	ek, _ := cur.ParentEdge()
+	for ek == edge.ParenExpr_X {
+		cur = cur.Parent()
+		ek, _ = cur.ParentEdge()
+	}
+
+	switch ek {
+	case edge.AssignStmt_Lhs:
+		assign := cur.Parent().Node().(*ast.AssignStmt)
+		if assign.Tok != token.DEFINE {
+			return true // i = j or i += j
+		}
+		id := curId.Node().(*ast.Ident)
+		if v, ok := info.Defs[id]; ok && v.Pos() != id.Pos() {
+			return true // reassignment of i (i, j := 1, 2)
+		}
+	case edge.IncDecStmt_X:
+		return true // i++, i--
+	case edge.UnaryExpr_X:
+		if cur.Parent().Node().(*ast.UnaryExpr).Op == token.AND {
+			return true // &i
+		}
+	}
+	return false
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/reflect.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/reflect.go
new file mode 100644
index 00000000000000..c9b0fa42eed0cc
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/reflect.go
@@ -0,0 +1,143 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+// This file defines modernizers that use the "reflect" package.
+
+import (
+	"go/ast"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+	"golang.org/x/tools/internal/versions"
+)
+
+var ReflectTypeForAnalyzer = &analysis.Analyzer{
+	Name: "reflecttypefor",
+	Doc:  analysisinternal.MustExtractDoc(doc, "reflecttypefor"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: reflecttypefor,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#reflecttypefor",
+}
+
+func reflecttypefor(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	var (
+		index = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info  = pass.TypesInfo
+
+		reflectTypeOf = index.Object("reflect", "TypeOf")
+	)
+
+	for curCall := range index.Calls(reflectTypeOf) {
+		call := curCall.Node().(*ast.CallExpr)
+		// Have: reflect.TypeOf(expr)
+
+		expr := call.Args[0]
+		if !typesinternal.NoEffects(info, expr) {
+			continue // don't eliminate operand: may have effects
+		}
+
+		t := info.TypeOf(expr)
+		var edits []analysis.TextEdit
+
+		// Special case for TypeOf((*T)(nil)).Elem(),
+		// needed when T is an interface type.
+		if astutil.IsChildOf(curCall, edge.SelectorExpr_X) {
+			curSel := unparenEnclosing(curCall).Parent()
+			if astutil.IsChildOf(curSel, edge.CallExpr_Fun) {
+				call2 := unparenEnclosing(curSel).Parent().Node().(*ast.CallExpr)
+				obj := typeutil.Callee(info, call2)
+				if typesinternal.IsMethodNamed(obj, "reflect", "Type", "Elem") {
+					if ptr, ok := t.(*types.Pointer); ok {
+						// Have: TypeOf(expr).Elem() where expr : *T
+						t = ptr.Elem()
+						// reflect.TypeOf(expr).Elem()
+						//                     -------
+						// reflect.TypeOf(expr)
+						edits = []analysis.TextEdit{{
+							Pos: call.End(),
+							End: call2.End(),
+						}}
+					}
+				}
+			}
+		}
+
+		// TypeOf(x) where x has an interface type is a
+		// dynamic operation; don't transform it to TypeFor.
+		// (edits == nil means "not the Elem() special case".)
+		if types.IsInterface(t) && edits == nil {
+			continue
+		}
+
+		file := astutil.EnclosingFile(curCall)
+		if versions.Before(info.FileVersions[file], "go1.22") {
+			continue // TypeFor requires go1.22
+		}
+		tokFile := pass.Fset.File(file.Pos())
+
+		// Format the type as valid Go syntax.
+		// TODO(adonovan): FileQualifier needs to respect
+		// visibility at the current point, and either fail
+		// or edit the imports as needed.
+		qual := typesinternal.FileQualifier(file, pass.Pkg)
+		tstr := types.TypeString(t, qual)
+
+		sel, ok := call.Fun.(*ast.SelectorExpr)
+		if !ok {
+			continue // e.g. reflect was dot-imported
+		}
+
+		// If the call argument contains the last use
+		// of a variable, as in:
+		//	var zero T
+		//	reflect.TypeOf(zero)
+		// remove the declaration of that variable.
+		curArg0 := curCall.ChildAt(edge.CallExpr_Args, 0)
+		edits = append(edits, refactor.DeleteUnusedVars(index, info, tokFile, curArg0)...)
+
+		pass.Report(analysis.Diagnostic{
+			Pos:     call.Fun.Pos(),
+			End:     call.Fun.End(),
+			Message: "reflect.TypeOf call can be simplified using TypeFor",
+			SuggestedFixes: []analysis.SuggestedFix{{
+				// reflect.TypeOf    (...T value...)
+				//         ------     -------------
+				// reflect.TypeFor[T](             )
+				Message: "Replace TypeOf by TypeFor",
+				TextEdits: append([]analysis.TextEdit{
+					{
+						Pos:     sel.Sel.Pos(),
+						End:     sel.Sel.End(),
+						NewText: []byte("TypeFor[" + tstr + "]"),
+					},
+					// delete (pure) argument
+					{
+						Pos: call.Lparen + 1,
+						End: call.Rparen,
+					},
+				}, edits...),
+			}},
+		})
+	}
+
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slices.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slices.go
new file mode 100644
index 00000000000000..032f874df1a875
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slices.go
@@ -0,0 +1,300 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+	"slices"
+	"strconv"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal"
+)
+
+// Warning: this analyzer is not safe to enable by default.
+var AppendClippedAnalyzer = &analysis.Analyzer{
+	Name: "appendclipped",
+	Doc:  analysisinternal.MustExtractDoc(doc, "appendclipped"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+	},
+	Run: appendclipped,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#appendclipped",
+}
+
+// The appendclipped pass offers to simplify a tower of append calls:
+//
+//	append(append(append(base, a...), b..., c...)
+//
+// with a call to go1.21's slices.Concat(base, a, b, c), or simpler
+// replacements such as slices.Clone(a) in degenerate cases.
+//
+// We offer bytes.Clone in preference to slices.Clone where
+// appropriate, if the package already imports "bytes";
+// their behaviors are identical.
+//
+// The base expression must denote a clipped slice (see [isClipped]
+// for definition), otherwise the replacement might eliminate intended
+// side effects to the base slice's array.
+//
+// Examples:
+//
+//	append(append(append(x[:0:0], a...), b...), c...) -> slices.Concat(a, b, c)
+//	append(append(slices.Clip(a), b...)               -> slices.Concat(a, b)
+//	append([]T{}, a...)                               -> slices.Clone(a)
+//	append([]string(nil), os.Environ()...)            -> os.Environ()
+//
+// The fix does not always preserve nilness the of base slice when the
+// addends (a, b, c) are all empty (see #73557).
+func appendclipped(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	// Skip the analyzer in packages where its
+	// fixes would create an import cycle.
+	if within(pass, "slices", "bytes", "runtime") {
+		return nil, nil
+	}
+
+	info := pass.TypesInfo
+
+	// sliceArgs is a non-empty (reversed) list of slices to be concatenated.
+	simplifyAppendEllipsis := func(file *ast.File, call *ast.CallExpr, base ast.Expr, sliceArgs []ast.Expr) {
+		// Only appends whose base is a clipped slice can be simplified:
+		// We must conservatively assume an append to an unclipped slice
+		// such as append(y[:0], x...) is intended to have effects on y.
+		clipped, empty := clippedSlice(info, base)
+		if clipped == nil {
+			return
+		}
+
+		// If any slice arg has a different type from the base
+		// (and thus the result) don't offer a fix, to avoid
+		// changing the return type, e.g:
+		//
+		//     type S []int
+		//   - x := append([]int(nil), S{}...) // x : []int
+		//   + x := slices.Clone(S{})          // x : S
+		//
+		// We could do better by inserting an explicit generic
+		// instantiation:
+		//
+		//   x := slices.Clone[[]int](S{})
+		//
+		// but this is often unnecessary and unwanted, such as
+		// when the value is used an in assignment context that
+		// provides an explicit type:
+		//
+		//   var x []int = slices.Clone(S{})
+		baseType := info.TypeOf(base)
+		for _, arg := range sliceArgs {
+			if !types.Identical(info.TypeOf(arg), baseType) {
+				return
+			}
+		}
+
+		// If the (clipped) base is empty, it may be safely ignored.
+		// Otherwise treat it (or its unclipped subexpression, if possible)
+		// as just another arg (the first) to Concat.
+		//
+		// TODO(adonovan): not so fast! If all the operands
+		// are empty, then the nilness of base matters, because
+		// append preserves nilness whereas Concat does not (#73557).
+		if !empty {
+			sliceArgs = append(sliceArgs, clipped)
+		}
+		slices.Reverse(sliceArgs)
+
+		// TODO(adonovan): simplify sliceArgs[0] further: slices.Clone(s) -> s
+
+		// Concat of a single (non-trivial) slice degenerates to Clone.
+		if len(sliceArgs) == 1 {
+			s := sliceArgs[0]
+
+			// Special case for common but redundant clone of os.Environ().
+			// append(zerocap, os.Environ()...) -> os.Environ()
+			if scall, ok := s.(*ast.CallExpr); ok {
+				obj := typeutil.Callee(info, scall)
+				if typesinternal.IsFunctionNamed(obj, "os", "Environ") {
+					pass.Report(analysis.Diagnostic{
+						Pos:     call.Pos(),
+						End:     call.End(),
+						Message: "Redundant clone of os.Environ()",
+						SuggestedFixes: []analysis.SuggestedFix{{
+							Message: "Eliminate redundant clone",
+							TextEdits: []analysis.TextEdit{{
+								Pos:     call.Pos(),
+								End:     call.End(),
+								NewText: []byte(astutil.Format(pass.Fset, s)),
+							}},
+						}},
+					})
+					return
+				}
+			}
+
+			// If the slice type is []byte, and the file imports
+			// "bytes" but not "slices", prefer the (behaviorally
+			// identical) bytes.Clone for local consistency.
+			// https://go.dev/issue/70815#issuecomment-2671572984
+			fileImports := func(path string) bool {
+				return slices.ContainsFunc(file.Imports, func(spec *ast.ImportSpec) bool {
+					value, _ := strconv.Unquote(spec.Path.Value)
+					return value == path
+				})
+			}
+			clonepkg := cond(
+				types.Identical(info.TypeOf(call), byteSliceType) &&
+					!fileImports("slices") && fileImports("bytes"),
+				"bytes",
+				"slices")
+
+			// append(zerocap, s...) -> slices.Clone(s) or bytes.Clone(s)
+			//
+			// This is unsound if s is empty and its nilness
+			// differs from zerocap (#73557).
+			prefix, importEdits := refactor.AddImport(info, file, clonepkg, clonepkg, "Clone", call.Pos())
+			message := fmt.Sprintf("Replace append with %s.Clone", clonepkg)
+			pass.Report(analysis.Diagnostic{
+				Pos:     call.Pos(),
+				End:     call.End(),
+				Message: message,
+				SuggestedFixes: []analysis.SuggestedFix{{
+					Message: message,
+					TextEdits: append(importEdits, []analysis.TextEdit{{
+						Pos:     call.Pos(),
+						End:     call.End(),
+						NewText: fmt.Appendf(nil, "%sClone(%s)", prefix, astutil.Format(pass.Fset, s)),
+					}}...),
+				}},
+			})
+			return
+		}
+
+		// append(append(append(base, a...), b..., c...) -> slices.Concat(base, a, b, c)
+		//
+		// This is unsound if all slices are empty and base is non-nil (#73557).
+		prefix, importEdits := refactor.AddImport(info, file, "slices", "slices", "Concat", call.Pos())
+		pass.Report(analysis.Diagnostic{
+			Pos:     call.Pos(),
+			End:     call.End(),
+			Message: "Replace append with slices.Concat",
+			SuggestedFixes: []analysis.SuggestedFix{{
+				Message: "Replace append with slices.Concat",
+				TextEdits: append(importEdits, []analysis.TextEdit{{
+					Pos:     call.Pos(),
+					End:     call.End(),
+					NewText: fmt.Appendf(nil, "%sConcat(%s)", prefix, formatExprs(pass.Fset, sliceArgs)),
+				}}...),
+			}},
+		})
+	}
+
+	// Mark nested calls to append so that we don't emit diagnostics for them.
+	skip := make(map[*ast.CallExpr]bool)
+
+	// Visit calls of form append(x, y...).
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	for curFile := range filesUsing(inspect, info, "go1.21") {
+		file := curFile.Node().(*ast.File)
+
+		for curCall := range curFile.Preorder((*ast.CallExpr)(nil)) {
+			call := curCall.Node().(*ast.CallExpr)
+			if skip[call] {
+				continue
+			}
+
+			// Recursively unwrap ellipsis calls to append, so
+			//   append(append(append(base, a...), b..., c...)
+			// yields (base, [c b a]).
+			base, slices := ast.Expr(call), []ast.Expr(nil) // base case: (call, nil)
+		again:
+			if call, ok := base.(*ast.CallExpr); ok {
+				if id, ok := call.Fun.(*ast.Ident); ok &&
+					call.Ellipsis.IsValid() &&
+					len(call.Args) == 2 &&
+					info.Uses[id] == builtinAppend {
+
+					// Have: append(base, s...)
+					base, slices = call.Args[0], append(slices, call.Args[1])
+					skip[call] = true
+					goto again
+				}
+			}
+
+			if len(slices) > 0 {
+				simplifyAppendEllipsis(file, call, base, slices)
+			}
+		}
+	}
+	return nil, nil
+}
+
+// clippedSlice returns res != nil if e denotes a slice that is
+// definitely clipped, that is, its len(s)==cap(s).
+//
+// The value of res is either the same as e or is a subexpression of e
+// that denotes the same slice but without the clipping operation.
+//
+// In addition, it reports whether the slice is definitely empty.
+//
+// Examples of clipped slices:
+//
+//	x[:0:0]				(empty)
+//	[]T(nil)			(empty)
+//	Slice{}				(empty)
+//	x[:len(x):len(x)]		(nonempty)  res=x
+//	x[:k:k]	 	         	(nonempty)
+//	slices.Clip(x)			(nonempty)  res=x
+//
+// TODO(adonovan): Add a check that the expression x has no side effects in
+// case x[:len(x):len(x)] -> x. Now the program behavior may change.
+func clippedSlice(info *types.Info, e ast.Expr) (res ast.Expr, empty bool) {
+	switch e := e.(type) {
+	case *ast.SliceExpr:
+		// x[:0:0], x[:len(x):len(x)], x[:k:k]
+		if e.Slice3 && e.High != nil && e.Max != nil && astutil.EqualSyntax(e.High, e.Max) { // x[:k:k]
+			res = e
+			empty = isZeroIntLiteral(info, e.High) // x[:0:0]
+			if call, ok := e.High.(*ast.CallExpr); ok &&
+				typeutil.Callee(info, call) == builtinLen &&
+				astutil.EqualSyntax(call.Args[0], e.X) {
+				res = e.X // x[:len(x):len(x)] -> x
+			}
+			return
+		}
+		return
+
+	case *ast.CallExpr:
+		// []T(nil)?
+		if info.Types[e.Fun].IsType() &&
+			is[*ast.Ident](e.Args[0]) &&
+			info.Uses[e.Args[0].(*ast.Ident)] == builtinNil {
+			return e, true
+		}
+
+		// slices.Clip(x)?
+		obj := typeutil.Callee(info, e)
+		if typesinternal.IsFunctionNamed(obj, "slices", "Clip") {
+			return e.Args[0], false // slices.Clip(x) -> x
+		}
+
+	case *ast.CompositeLit:
+		// Slice{}?
+		if len(e.Elts) == 0 {
+			return e, true
+		}
+	}
+	return nil, false
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slicescontains.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slicescontains.go
new file mode 100644
index 00000000000000..b3c2e562c9a464
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slicescontains.go
@@ -0,0 +1,433 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typeparams"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var SlicesContainsAnalyzer = &analysis.Analyzer{
+	Name: "slicescontains",
+	Doc:  analysisinternal.MustExtractDoc(doc, "slicescontains"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: slicescontains,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#slicescontains",
+}
+
+// The slicescontains pass identifies loops that can be replaced by a
+// call to slices.Contains{,Func}. For example:
+//
+//	for i, elem := range s {
+//		if elem == needle {
+//			...
+//			break
+//		}
+//	}
+//
+// =>
+//
+//	if slices.Contains(s, needle) { ... }
+//
+// Variants:
+//   - if the if-condition is f(elem), the replacement
+//     uses slices.ContainsFunc(s, f).
+//   - if the if-body is "return true" and the fallthrough
+//     statement is "return false" (or vice versa), the
+//     loop becomes "return [!]slices.Contains(...)".
+//   - if the if-body is "found = true" and the previous
+//     statement is "found = false" (or vice versa), the
+//     loop becomes "found = [!]slices.Contains(...)".
+//
+// It may change cardinality of effects of the "needle" expression.
+// (Mostly this appears to be a desirable optimization, avoiding
+// redundantly repeated evaluation.)
+//
+// TODO(adonovan): Add a check that needle/predicate expression from
+// if-statement has no effects. Now the program behavior may change.
+func slicescontains(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	// Skip the analyzer in packages where its
+	// fixes would create an import cycle.
+	if within(pass, "slices", "runtime") {
+		return nil, nil
+	}
+
+	var (
+		inspect = pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		index   = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info    = pass.TypesInfo
+	)
+
+	// check is called for each RangeStmt of this form:
+	//   for i, elem := range s { if cond { ... } }
+	check := func(file *ast.File, curRange inspector.Cursor) {
+		rng := curRange.Node().(*ast.RangeStmt)
+		ifStmt := rng.Body.List[0].(*ast.IfStmt)
+
+		// isSliceElem reports whether e denotes the
+		// current slice element (elem or s[i]).
+		isSliceElem := func(e ast.Expr) bool {
+			if rng.Value != nil && astutil.EqualSyntax(e, rng.Value) {
+				return true // "elem"
+			}
+			if x, ok := e.(*ast.IndexExpr); ok &&
+				astutil.EqualSyntax(x.X, rng.X) &&
+				astutil.EqualSyntax(x.Index, rng.Key) {
+				return true // "s[i]"
+			}
+			return false
+		}
+
+		// Examine the condition for one of these forms:
+		//
+		// - if elem or s[i] == needle  { ... } => Contains
+		// - if predicate(s[i] or elem) { ... } => ContainsFunc
+		var (
+			funcName string   // "Contains" or "ContainsFunc"
+			arg2     ast.Expr // second argument to func (needle or predicate)
+		)
+		switch cond := ifStmt.Cond.(type) {
+		case *ast.BinaryExpr:
+			if cond.Op == token.EQL {
+				var elem ast.Expr
+				if isSliceElem(cond.X) {
+					funcName = "Contains"
+					elem = cond.X
+					arg2 = cond.Y // "if elem == needle"
+				} else if isSliceElem(cond.Y) {
+					funcName = "Contains"
+					elem = cond.Y
+					arg2 = cond.X // "if needle == elem"
+				}
+
+				// Reject if elem and needle have different types.
+				if elem != nil {
+					tElem := info.TypeOf(elem)
+					tNeedle := info.TypeOf(arg2)
+					if !types.Identical(tElem, tNeedle) {
+						// Avoid ill-typed slices.Contains([]error, any).
+						if !types.AssignableTo(tNeedle, tElem) {
+							return
+						}
+						// TODO(adonovan): relax this check to allow
+						//   slices.Contains([]error, error(any)),
+						// inserting an explicit widening conversion
+						// around the needle.
+						return
+					}
+				}
+			}
+
+		case *ast.CallExpr:
+			if len(cond.Args) == 1 &&
+				isSliceElem(cond.Args[0]) &&
+				typeutil.Callee(info, cond) != nil { // not a conversion
+
+				// Attempt to get signature
+				sig, isSignature := info.TypeOf(cond.Fun).(*types.Signature)
+				if isSignature {
+					// skip variadic functions
+					if sig.Variadic() {
+						return
+					}
+
+					// Slice element type must match function parameter type.
+					var (
+						tElem  = typeparams.CoreType(info.TypeOf(rng.X)).(*types.Slice).Elem()
+						tParam = sig.Params().At(0).Type()
+					)
+					if !types.Identical(tElem, tParam) {
+						return
+					}
+				}
+
+				funcName = "ContainsFunc"
+				arg2 = cond.Fun // "if predicate(elem)"
+			}
+		}
+		if funcName == "" {
+			return // not a candidate for Contains{,Func}
+		}
+
+		// body is the "true" body.
+		body := ifStmt.Body
+		if len(body.List) == 0 {
+			// (We could perhaps delete the loop entirely.)
+			return
+		}
+
+		// Reject if the body, needle or predicate references either range variable.
+		usesRangeVar := func(n ast.Node) bool {
+			cur, ok := curRange.FindNode(n)
+			if !ok {
+				panic(fmt.Sprintf("FindNode(%T) failed", n))
+			}
+			return uses(index, cur, info.Defs[rng.Key.(*ast.Ident)]) ||
+				rng.Value != nil && uses(index, cur, info.Defs[rng.Value.(*ast.Ident)])
+		}
+		if usesRangeVar(body) {
+			// Body uses range var "i" or "elem".
+			//
+			// (The check for "i" could be relaxed when we
+			// generalize this to support slices.Index;
+			// and the check for "elem" could be relaxed
+			// if "elem" can safely be replaced in the
+			// body by "needle".)
+			return
+		}
+		if usesRangeVar(arg2) {
+			return
+		}
+
+		// Prepare slices.Contains{,Func} call.
+		prefix, importEdits := refactor.AddImport(info, file, "slices", "slices", funcName, rng.Pos())
+		contains := fmt.Sprintf("%s%s(%s, %s)",
+			prefix,
+			funcName,
+			astutil.Format(pass.Fset, rng.X),
+			astutil.Format(pass.Fset, arg2))
+
+		report := func(edits []analysis.TextEdit) {
+			pass.Report(analysis.Diagnostic{
+				Pos:     rng.Pos(),
+				End:     rng.End(),
+				Message: fmt.Sprintf("Loop can be simplified using slices.%s", funcName),
+				SuggestedFixes: []analysis.SuggestedFix{{
+					Message:   "Replace loop by call to slices." + funcName,
+					TextEdits: append(edits, importEdits...),
+				}},
+			})
+		}
+
+		// Last statement of body must return/break out of the loop.
+		//
+		// TODO(adonovan): opt:consider avoiding FindNode with new API of form:
+		//    curRange.Get(edge.RangeStmt_Body, -1).
+		//             Get(edge.BodyStmt_List, 0).
+		//             Get(edge.IfStmt_Body)
+		curBody, _ := curRange.FindNode(body)
+		curLastStmt, _ := curBody.LastChild()
+
+		// Reject if any statement in the body except the
+		// last has a free continuation (continue or break)
+		// that might affected by melting down the loop.
+		//
+		// TODO(adonovan): relax check by analyzing branch target.
+		for curBodyStmt := range curBody.Children() {
+			if curBodyStmt != curLastStmt {
+				for range curBodyStmt.Preorder((*ast.BranchStmt)(nil), (*ast.ReturnStmt)(nil)) {
+					return
+				}
+			}
+		}
+
+		switch lastStmt := curLastStmt.Node().(type) {
+		case *ast.ReturnStmt:
+			// Have: for ... range seq { if ... { stmts; return x } }
+
+			// Special case:
+			// body={ return true } next="return false"   (or negation)
+			// => return [!]slices.Contains(...)
+			if curNext, ok := curRange.NextSibling(); ok {
+				nextStmt := curNext.Node().(ast.Stmt)
+				tval := isReturnTrueOrFalse(info, lastStmt)
+				fval := isReturnTrueOrFalse(info, nextStmt)
+				if len(body.List) == 1 && tval*fval < 0 {
+					//    for ... { if ... { return true/false } }
+					// => return [!]slices.Contains(...)
+					report([]analysis.TextEdit{
+						// Delete the range statement and following space.
+						{
+							Pos: rng.Pos(),
+							End: nextStmt.Pos(),
+						},
+						// Change return to [!]slices.Contains(...).
+						{
+							Pos: nextStmt.Pos(),
+							End: nextStmt.End(),
+							NewText: fmt.Appendf(nil, "return %s%s",
+								cond(tval > 0, "", "!"),
+								contains),
+						},
+					})
+					return
+				}
+			}
+
+			// General case:
+			// => if slices.Contains(...) { stmts; return x }
+			report([]analysis.TextEdit{
+				// Replace "for ... { if ... " with "if slices.Contains(...)".
+				{
+					Pos:     rng.Pos(),
+					End:     ifStmt.Body.Pos(),
+					NewText: fmt.Appendf(nil, "if %s ", contains),
+				},
+				// Delete '}' of range statement and preceding space.
+				{
+					Pos: ifStmt.Body.End(),
+					End: rng.End(),
+				},
+			})
+			return
+
+		case *ast.BranchStmt:
+			if lastStmt.Tok == token.BREAK && lastStmt.Label == nil { // unlabeled break
+				// Have: for ... { if ... { stmts; break } }
+
+				var prevStmt ast.Stmt // previous statement to range (if any)
+				if curPrev, ok := curRange.PrevSibling(); ok {
+					// If the RangeStmt's previous sibling is a Stmt,
+					// the RangeStmt must be among the Body list of
+					// a BlockStmt, CauseClause, or CommClause.
+					// In all cases, the prevStmt is the immediate
+					// predecessor of the RangeStmt during execution.
+					//
+					// (This is not true for Stmts in general;
+					// see [Cursor.Children] and #71074.)
+					prevStmt, _ = curPrev.Node().(ast.Stmt)
+				}
+
+				// Special case:
+				// prev="lhs = false" body={ lhs = true; break }
+				// => lhs = slices.Contains(...) (or negation)
+				if assign, ok := body.List[0].(*ast.AssignStmt); ok &&
+					len(body.List) == 2 &&
+					assign.Tok == token.ASSIGN &&
+					len(assign.Lhs) == 1 &&
+					len(assign.Rhs) == 1 {
+
+					// Have: body={ lhs = rhs; break }
+
+					if prevAssign, ok := prevStmt.(*ast.AssignStmt); ok &&
+						len(prevAssign.Lhs) == 1 &&
+						len(prevAssign.Rhs) == 1 &&
+						astutil.EqualSyntax(prevAssign.Lhs[0], assign.Lhs[0]) &&
+						is[*ast.Ident](assign.Rhs[0]) &&
+						info.Uses[assign.Rhs[0].(*ast.Ident)] == builtinTrue {
+
+						// Have:
+						//    lhs = false
+						//    for ... { if ... { lhs = true; break } }
+						//  =>
+						//    lhs = slices.Contains(...)
+						//
+						// TODO(adonovan):
+						// - support "var lhs bool = false" and variants.
+						// - support negation.
+						// Both these variants seem quite significant.
+						// - allow the break to be omitted.
+						report([]analysis.TextEdit{
+							// Replace "rhs" of previous assignment by slices.Contains(...)
+							{
+								Pos:     prevAssign.Rhs[0].Pos(),
+								End:     prevAssign.Rhs[0].End(),
+								NewText: []byte(contains),
+							},
+							// Delete the loop and preceding space.
+							{
+								Pos: prevAssign.Rhs[0].End(),
+								End: rng.End(),
+							},
+						})
+						return
+					}
+				}
+
+				// General case:
+				//    for ... { if ...        { stmts; break } }
+				// => if slices.Contains(...) { stmts        }
+				report([]analysis.TextEdit{
+					// Replace "for ... { if ... " with "if slices.Contains(...)".
+					{
+						Pos:     rng.Pos(),
+						End:     ifStmt.Body.Pos(),
+						NewText: fmt.Appendf(nil, "if %s ", contains),
+					},
+					// Delete break statement and preceding space.
+					{
+						Pos: func() token.Pos {
+							if len(body.List) > 1 {
+								beforeBreak, _ := curLastStmt.PrevSibling()
+								return beforeBreak.Node().End()
+							}
+							return lastStmt.Pos()
+						}(),
+						End: lastStmt.End(),
+					},
+					// Delete '}' of range statement and preceding space.
+					{
+						Pos: ifStmt.Body.End(),
+						End: rng.End(),
+					},
+				})
+				return
+			}
+		}
+	}
+
+	for curFile := range filesUsing(inspect, info, "go1.21") {
+		file := curFile.Node().(*ast.File)
+
+		for curRange := range curFile.Preorder((*ast.RangeStmt)(nil)) {
+			rng := curRange.Node().(*ast.RangeStmt)
+
+			if is[*ast.Ident](rng.Key) &&
+				rng.Tok == token.DEFINE &&
+				len(rng.Body.List) == 1 &&
+				is[*types.Slice](typeparams.CoreType(info.TypeOf(rng.X))) {
+
+				// Have:
+				// - for _, elem := range s { S }
+				// - for i       := range s { S }
+
+				if ifStmt, ok := rng.Body.List[0].(*ast.IfStmt); ok &&
+					ifStmt.Init == nil && ifStmt.Else == nil {
+
+					// Have: for i, elem := range s { if cond { ... } }
+					check(file, curRange)
+				}
+			}
+		}
+	}
+	return nil, nil
+}
+
+// -- helpers --
+
+// isReturnTrueOrFalse returns nonzero if stmt returns true (+1) or false (-1).
+func isReturnTrueOrFalse(info *types.Info, stmt ast.Stmt) int {
+	if ret, ok := stmt.(*ast.ReturnStmt); ok && len(ret.Results) == 1 {
+		if id, ok := ret.Results[0].(*ast.Ident); ok {
+			switch info.Uses[id] {
+			case builtinTrue:
+				return +1
+			case builtinFalse:
+				return -1
+			}
+		}
+	}
+	return 0
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slicesdelete.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slicesdelete.go
new file mode 100644
index 00000000000000..b3e063db0fbf9e
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/slicesdelete.go
@@ -0,0 +1,184 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal"
+)
+
+// Warning: this analyzer is not safe to enable by default (not nil-preserving).
+var SlicesDeleteAnalyzer = &analysis.Analyzer{
+	Name: "slicesdelete",
+	Doc:  analysisinternal.MustExtractDoc(doc, "slicesdelete"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+	},
+	Run: slicesdelete,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#slicesdelete",
+}
+
+// The slicesdelete pass attempts to replace instances of append(s[:i], s[i+k:]...)
+// with slices.Delete(s, i, i+k) where k is some positive constant.
+// Other variations that will also have suggested replacements include:
+// append(s[:i-1], s[i:]...) and append(s[:i+k1], s[i+k2:]) where k2 > k1.
+func slicesdelete(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	// Skip the analyzer in packages where its
+	// fixes would create an import cycle.
+	if within(pass, "slices", "runtime") {
+		return nil, nil
+	}
+
+	inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+	info := pass.TypesInfo
+	report := func(file *ast.File, call *ast.CallExpr, slice1, slice2 *ast.SliceExpr) {
+		insert := func(pos token.Pos, text string) analysis.TextEdit {
+			return analysis.TextEdit{Pos: pos, End: pos, NewText: []byte(text)}
+		}
+		isIntExpr := func(e ast.Expr) bool {
+			return types.Identical(types.Default(info.TypeOf(e)), builtinInt.Type())
+		}
+		isIntShadowed := func() bool {
+			scope := pass.TypesInfo.Scopes[file].Innermost(call.Lparen)
+			if _, obj := scope.LookupParent("int", call.Lparen); obj != builtinInt {
+				return true // int type is shadowed
+			}
+			return false
+		}
+
+		prefix, edits := refactor.AddImport(info, file, "slices", "slices", "Delete", call.Pos())
+		// append's indices may be any integer type; slices.Delete requires int.
+		// Insert int conversions as needed (and if possible).
+		if isIntShadowed() && (!isIntExpr(slice1.High) || !isIntExpr(slice2.Low)) {
+			return
+		}
+		if !isIntExpr(slice1.High) {
+			edits = append(edits,
+				insert(slice1.High.Pos(), "int("),
+				insert(slice1.High.End(), ")"),
+			)
+		}
+		if !isIntExpr(slice2.Low) {
+			edits = append(edits,
+				insert(slice2.Low.Pos(), "int("),
+				insert(slice2.Low.End(), ")"),
+			)
+		}
+
+		pass.Report(analysis.Diagnostic{
+			Pos:     call.Pos(),
+			End:     call.End(),
+			Message: "Replace append with slices.Delete",
+			SuggestedFixes: []analysis.SuggestedFix{{
+				Message: "Replace append with slices.Delete",
+				TextEdits: append(edits, []analysis.TextEdit{
+					// Change name of called function.
+					{
+						Pos:     call.Fun.Pos(),
+						End:     call.Fun.End(),
+						NewText: []byte(prefix + "Delete"),
+					},
+					// Delete ellipsis.
+					{
+						Pos: call.Ellipsis,
+						End: call.Ellipsis + token.Pos(len("...")), // delete ellipsis
+					},
+					// Remove second slice variable name.
+					{
+						Pos: slice2.X.Pos(),
+						End: slice2.X.End(),
+					},
+					// Insert after first slice variable name.
+					{
+						Pos:     slice1.X.End(),
+						NewText: []byte(", "),
+					},
+					// Remove brackets and colons.
+					{
+						Pos: slice1.Lbrack,
+						End: slice1.High.Pos(),
+					},
+					{
+						Pos: slice1.Rbrack,
+						End: slice1.Rbrack + 1,
+					},
+					{
+						Pos: slice2.Lbrack,
+						End: slice2.Lbrack + 1,
+					},
+					{
+						Pos: slice2.Low.End(),
+						End: slice2.Rbrack + 1,
+					},
+				}...),
+			}},
+		})
+	}
+	for curFile := range filesUsing(inspect, info, "go1.21") {
+		file := curFile.Node().(*ast.File)
+		for curCall := range curFile.Preorder((*ast.CallExpr)(nil)) {
+			call := curCall.Node().(*ast.CallExpr)
+			if id, ok := call.Fun.(*ast.Ident); ok && len(call.Args) == 2 {
+				// Verify we have append with two slices and ... operator,
+				// the first slice has no low index and second slice has no
+				// high index, and not a three-index slice.
+				if call.Ellipsis.IsValid() && info.Uses[id] == builtinAppend {
+					slice1, ok1 := call.Args[0].(*ast.SliceExpr)
+					slice2, ok2 := call.Args[1].(*ast.SliceExpr)
+					if ok1 && slice1.Low == nil && !slice1.Slice3 &&
+						ok2 && slice2.High == nil && !slice2.Slice3 &&
+						astutil.EqualSyntax(slice1.X, slice2.X) &&
+						typesinternal.NoEffects(info, slice1.X) &&
+						increasingSliceIndices(info, slice1.High, slice2.Low) {
+						// Have append(s[:a], s[b:]...) where we can verify a < b.
+						report(file, call, slice1, slice2)
+					}
+				}
+			}
+		}
+	}
+	return nil, nil
+}
+
+// Given two slice indices a and b, returns true if we can verify that a < b.
+// It recognizes certain forms such as i+k1 < i+k2 where k1 < k2.
+func increasingSliceIndices(info *types.Info, a, b ast.Expr) bool {
+	// Given an expression of the form i±k, returns (i, k)
+	// where k is a signed constant. Otherwise it returns (e, 0).
+	split := func(e ast.Expr) (ast.Expr, constant.Value) {
+		if binary, ok := e.(*ast.BinaryExpr); ok && (binary.Op == token.SUB || binary.Op == token.ADD) {
+			// Negate constants if operation is subtract instead of add
+			if k := info.Types[binary.Y].Value; k != nil {
+				return binary.X, constant.UnaryOp(binary.Op, k, 0) // i ± k
+			}
+		}
+		return e, constant.MakeInt64(0)
+	}
+
+	// Handle case where either a or b is a constant
+	ak := info.Types[a].Value
+	bk := info.Types[b].Value
+	if ak != nil || bk != nil {
+		return ak != nil && bk != nil && constant.Compare(ak, token.LSS, bk)
+	}
+
+	ai, ak := split(a)
+	bi, bk := split(b)
+	return astutil.EqualSyntax(ai, bi) && constant.Compare(ak, token.LSS, bk)
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/sortslice.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/sortslice.go
new file mode 100644
index 00000000000000..66af16d1f66f39
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/sortslice.go
@@ -0,0 +1,124 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+// (Not to be confused with go/analysis/passes/sortslice.)
+var SlicesSortAnalyzer = &analysis.Analyzer{
+	Name: "slicessort",
+	Doc:  analysisinternal.MustExtractDoc(doc, "slicessort"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: slicessort,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#slicessort",
+}
+
+// The slicessort pass replaces sort.Slice(slice, less) with
+// slices.Sort(slice) when slice is a []T and less is a FuncLit
+// equivalent to cmp.Ordered[T].
+//
+//		sort.Slice(s, func(i, j int) bool { return s[i] < s[j] })
+//	  =>	slices.Sort(s)
+//
+// There is no slices.SortStable.
+//
+// TODO(adonovan): support
+//
+//   - sort.Slice(s, func(i, j int) bool { return s[i] ... s[j] })
+//     -> slices.SortFunc(s, func(x, y T) int { return x ... y })
+//     iff all uses of i, j can be replaced by s[i], s[j] and "<" can be replaced with cmp.Compare.
+//
+//   - As above for sort.SliceStable -> slices.SortStableFunc.
+//
+//   - sort.Sort(x) where x has a named slice type whose Less method is the natural order.
+//     -> sort.Slice(x)
+func slicessort(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	// Skip the analyzer in packages where its
+	// fixes would create an import cycle.
+	if within(pass, "slices", "sort", "runtime") {
+		return nil, nil
+	}
+
+	var (
+		info      = pass.TypesInfo
+		index     = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		sortSlice = index.Object("sort", "Slice")
+	)
+	for curCall := range index.Calls(sortSlice) {
+		call := curCall.Node().(*ast.CallExpr)
+		if lit, ok := call.Args[1].(*ast.FuncLit); ok && len(lit.Body.List) == 1 {
+			sig := info.Types[lit.Type].Type.(*types.Signature)
+
+			// Have: sort.Slice(s, func(i, j int) bool { return ... })
+			s := call.Args[0]
+			i := sig.Params().At(0)
+			j := sig.Params().At(1)
+
+			if ret, ok := lit.Body.List[0].(*ast.ReturnStmt); ok {
+				if compare, ok := ret.Results[0].(*ast.BinaryExpr); ok && compare.Op == token.LSS {
+					// isIndex reports whether e is s[v].
+					isIndex := func(e ast.Expr, v *types.Var) bool {
+						index, ok := e.(*ast.IndexExpr)
+						return ok &&
+							astutil.EqualSyntax(index.X, s) &&
+							is[*ast.Ident](index.Index) &&
+							info.Uses[index.Index.(*ast.Ident)] == v
+					}
+					file := astutil.EnclosingFile(curCall)
+					if isIndex(compare.X, i) && isIndex(compare.Y, j) &&
+						fileUses(info, file, "go1.21") {
+						// Have: sort.Slice(s, func(i, j int) bool { return s[i] < s[j] })
+
+						prefix, importEdits := refactor.AddImport(
+							info, file, "slices", "slices", "Sort", call.Pos())
+
+						pass.Report(analysis.Diagnostic{
+							// Highlight "sort.Slice".
+							Pos:     call.Fun.Pos(),
+							End:     call.Fun.End(),
+							Message: "sort.Slice can be modernized using slices.Sort",
+							SuggestedFixes: []analysis.SuggestedFix{{
+								Message: "Replace sort.Slice call by slices.Sort",
+								TextEdits: append(importEdits, []analysis.TextEdit{
+									{
+										// Replace sort.Slice with slices.Sort.
+										Pos:     call.Fun.Pos(),
+										End:     call.Fun.End(),
+										NewText: []byte(prefix + "Sort"),
+									},
+									{
+										// Eliminate FuncLit.
+										Pos: call.Args[0].End(),
+										End: call.Rparen,
+									},
+								}...),
+							}},
+						})
+					}
+				}
+			}
+		}
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stditerators.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stditerators.go
new file mode 100644
index 00000000000000..20817520e1b14f
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stditerators.go
@@ -0,0 +1,354 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/goplsexport"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/stdlib"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var stditeratorsAnalyzer = &analysis.Analyzer{
+	Name: "stditerators",
+	Doc:  analysisinternal.MustExtractDoc(doc, "stditerators"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: stditerators,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#stditerators",
+}
+
+func init() {
+	// Export to gopls until this is a published modernizer.
+	goplsexport.StdIteratorsModernizer = stditeratorsAnalyzer
+}
+
+// stditeratorsTable records std types that have legacy T.{Len,At}
+// iteration methods as well as a newer T.All method that returns an
+// iter.Seq.
+var stditeratorsTable = [...]struct {
+	pkgpath, typename, lenmethod, atmethod, itermethod, elemname string
+}{
+	// Example: in go/types, (*Tuple).Variables returns an
+	// iterator that replaces a loop over (*Tuple).{Len,At}.
+	// The loop variable is named "v".
+	{"go/types", "Interface", "NumEmbeddeds", "EmbeddedType", "EmbeddedTypes", "etyp"},
+	{"go/types", "Interface", "NumExplicitMethods", "ExplicitMethod", "ExplicitMethods", "method"},
+	{"go/types", "Interface", "NumMethods", "Method", "Methods", "method"},
+	{"go/types", "MethodSet", "Len", "At", "Methods", "method"},
+	{"go/types", "Named", "NumMethods", "Method", "Methods", "method"},
+	{"go/types", "Scope", "NumChildren", "Child", "Children", "child"},
+	{"go/types", "Struct", "NumFields", "Field", "Fields", "field"},
+	{"go/types", "Tuple", "Len", "At", "Variables", "v"},
+	{"go/types", "TypeList", "Len", "At", "Types", "t"},
+	{"go/types", "TypeParamList", "Len", "At", "TypeParams", "tparam"},
+	{"go/types", "Union", "Len", "Term", "Terms", "term"},
+	// TODO(adonovan): support Seq2. Bonus: transform uses of both key and value.
+	// {"reflect", "Value", "NumFields", "Field", "Fields", "field"},
+}
+
+// stditerators suggests fixes to replace loops using Len/At-style
+// iterator APIs by a range loop over an iterator. The set of
+// participating types and methods is defined by [iteratorsTable].
+//
+// Pattern:
+//
+//	for i := 0; i < x.Len(); i++ {
+//		use(x.At(i))
+//	}
+//
+// =>
+//
+//	for elem := range x.All() {
+//		use(elem)
+//	}
+//
+// Variant:
+//
+//	for i := range x.Len() { ... }
+//
+// Note: Iterators have a dynamic cost. How do we know that
+// the user hasn't intentionally chosen not to use an
+// iterator for that reason? We don't want to go fix to
+// undo optimizations. Do we need a suppression mechanism?
+func stditerators(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	var (
+		index = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info  = pass.TypesInfo
+	)
+
+	for _, row := range stditeratorsTable {
+		// Don't offer fixes within the package
+		// that defines the iterator in question.
+		if within(pass, row.pkgpath) {
+			continue
+		}
+
+		var (
+			lenMethod = index.Selection(row.pkgpath, row.typename, row.lenmethod)
+			atMethod  = index.Selection(row.pkgpath, row.typename, row.atmethod)
+		)
+
+		// chooseName returns an appropriate fresh name
+		// for the index variable of the iterator loop
+		// whose body is specified.
+		//
+		// If the loop body starts with
+		//
+		//     for ... { e := x.At(i); use(e) }
+		//
+		// then chooseName prefers the name e and additionally
+		// returns the var's symbol. We'll transform this to:
+		//
+		//     for e := range x.Len() { e := e; use(e) }
+		//
+		// which leaves a redundant assignment that a
+		// subsequent 'forvar' pass will eliminate.
+		chooseName := func(curBody inspector.Cursor, x ast.Expr, i *types.Var) (string, *types.Var) {
+			// Is body { elem := x.At(i); ... } ?
+			body := curBody.Node().(*ast.BlockStmt)
+			if len(body.List) > 0 {
+				if assign, ok := body.List[0].(*ast.AssignStmt); ok &&
+					assign.Tok == token.DEFINE &&
+					len(assign.Lhs) == 1 &&
+					len(assign.Rhs) == 1 &&
+					is[*ast.Ident](assign.Lhs[0]) {
+					// call to x.At(i)?
+					if call, ok := assign.Rhs[0].(*ast.CallExpr); ok &&
+						typeutil.Callee(info, call) == atMethod &&
+						astutil.EqualSyntax(ast.Unparen(call.Fun).(*ast.SelectorExpr).X, x) &&
+						is[*ast.Ident](call.Args[0]) &&
+						info.Uses[call.Args[0].(*ast.Ident)] == i {
+						// Have: { elem := x.At(i); ... }
+						id := assign.Lhs[0].(*ast.Ident)
+						return id.Name, info.Defs[id].(*types.Var)
+					}
+				}
+			}
+
+			loop := curBody.Parent().Node()
+			return refactor.FreshName(info.Scopes[loop], loop.Pos(), row.elemname), nil
+		}
+
+		// Process each call of x.Len().
+	nextCall:
+		for curLenCall := range index.Calls(lenMethod) {
+			lenSel, ok := ast.Unparen(curLenCall.Node().(*ast.CallExpr).Fun).(*ast.SelectorExpr)
+			if !ok {
+				continue
+			}
+			// lenSel is "x.Len"
+
+			var (
+				rng      analysis.Range   // where to report diagnostic
+				curBody  inspector.Cursor // loop body
+				indexVar *types.Var       // old loop index var
+				elemVar  *types.Var       // existing "elem := x.At(i)" var, if present
+				elem     string           // name for new loop var
+				edits    []analysis.TextEdit
+			)
+
+			// Analyze enclosing loop.
+			switch ek, _ := curLenCall.ParentEdge(); ek {
+			case edge.BinaryExpr_Y:
+				// pattern 1: for i := 0; i < x.Len(); i++ { ... }
+				var (
+					curCmp = curLenCall.Parent()
+					cmp    = curCmp.Node().(*ast.BinaryExpr)
+				)
+				if cmp.Op != token.LSS ||
+					!astutil.IsChildOf(curCmp, edge.ForStmt_Cond) {
+					continue
+				}
+				if id, ok := cmp.X.(*ast.Ident); ok {
+					// Have: for _; i < x.Len(); _ { ... }
+					var (
+						v      = info.Uses[id].(*types.Var)
+						curFor = curCmp.Parent()
+						loop   = curFor.Node().(*ast.ForStmt)
+					)
+					if v != isIncrementLoop(info, loop) {
+						continue
+					}
+					// Have: for i := 0; i < x.Len(); i++ { ... }.
+					//       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+					rng = analysisinternal.Range(loop.For, loop.Post.End())
+					indexVar = v
+					curBody = curFor.ChildAt(edge.ForStmt_Body, -1)
+					elem, elemVar = chooseName(curBody, lenSel.X, indexVar)
+
+					//	for i    := 0; i < x.Len(); i++ {
+					//          ----    -------  ---  -----
+					//	for elem := range  x.All()      {
+					edits = []analysis.TextEdit{
+						{
+							Pos:     v.Pos(),
+							End:     v.Pos() + token.Pos(len(v.Name())),
+							NewText: []byte(elem),
+						},
+						{
+							Pos:     loop.Init.(*ast.AssignStmt).Rhs[0].Pos(),
+							End:     cmp.Y.Pos(),
+							NewText: []byte("range "),
+						},
+						{
+							Pos:     lenSel.Sel.Pos(),
+							End:     lenSel.Sel.End(),
+							NewText: []byte(row.itermethod),
+						},
+						{
+							Pos: curLenCall.Node().End(),
+							End: loop.Post.End(),
+						},
+					}
+				}
+
+			case edge.RangeStmt_X:
+				// pattern 2: for i := range x.Len() { ... }
+				var (
+					curRange = curLenCall.Parent()
+					loop     = curRange.Node().(*ast.RangeStmt)
+				)
+				if id, ok := loop.Key.(*ast.Ident); ok &&
+					loop.Value == nil &&
+					loop.Tok == token.DEFINE {
+					// Have: for i := range x.Len() { ... }
+					//                ~~~~~~~~~~~~~
+
+					rng = analysisinternal.Range(loop.Range, loop.X.End())
+					indexVar = info.Defs[id].(*types.Var)
+					curBody = curRange.ChildAt(edge.RangeStmt_Body, -1)
+					elem, elemVar = chooseName(curBody, lenSel.X, indexVar)
+
+					//	for i    := range x.Len() {
+					//          ----            ---
+					//	for elem := range x.All() {
+					edits = []analysis.TextEdit{
+						{
+							Pos:     loop.Key.Pos(),
+							End:     loop.Key.End(),
+							NewText: []byte(elem),
+						},
+						{
+							Pos:     lenSel.Sel.Pos(),
+							End:     lenSel.Sel.End(),
+							NewText: []byte(row.itermethod),
+						},
+					}
+				}
+			}
+
+			if indexVar == nil {
+				continue // no loop of the required form
+			}
+
+			// TODO(adonovan): what about possible
+			// modifications of x within the loop?
+			// Aliasing seems to make a conservative
+			// treatment impossible.
+
+			// Check that all uses of var i within loop body are x.At(i).
+			for curUse := range index.Uses(indexVar) {
+				if !curBody.Contains(curUse) {
+					continue
+				}
+				if ek, argidx := curUse.ParentEdge(); ek != edge.CallExpr_Args || argidx != 0 {
+					continue nextCall // use is not arg of call
+				}
+				curAtCall := curUse.Parent()
+				atCall := curAtCall.Node().(*ast.CallExpr)
+				if typeutil.Callee(info, atCall) != atMethod {
+					continue nextCall // use is not arg of call to T.At
+				}
+				atSel := ast.Unparen(atCall.Fun).(*ast.SelectorExpr)
+
+				// Check receivers of Len, At calls match (syntactically).
+				if !astutil.EqualSyntax(lenSel.X, atSel.X) {
+					continue nextCall
+				}
+
+				// At each point of use, check that
+				// the fresh variable is not shadowed
+				// by an intervening local declaration
+				// (or by the idiomatic elemVar optionally
+				// found by chooseName).
+				if obj := lookup(info, curAtCall, elem); obj != nil && obj != elemVar && obj.Pos() > indexVar.Pos() {
+					// (Ideally, instead of giving up, we would
+					// embellish the name and try again.)
+					continue nextCall
+				}
+
+				// use(x.At(i))
+				//     -------
+				// use(elem   )
+				edits = append(edits, analysis.TextEdit{
+					Pos:     atCall.Pos(),
+					End:     atCall.End(),
+					NewText: []byte(elem),
+				})
+			}
+
+			// Check file Go version is new enough for the iterator method.
+			// (In the long run, version filters are not highly selective,
+			// so there's no need to do them first, especially as this check
+			// may be somewhat expensive.)
+			if v, ok := methodGoVersion(row.pkgpath, row.typename, row.itermethod); !ok {
+				panic("no version found")
+			} else if file := astutil.EnclosingFile(curLenCall); !fileUses(info, file, v.String()) {
+				continue nextCall
+			}
+
+			pass.Report(analysis.Diagnostic{
+				Pos: rng.Pos(),
+				End: rng.End(),
+				Message: fmt.Sprintf("%s/%s loop can simplified using %s.%s iteration",
+					row.lenmethod, row.atmethod, row.typename, row.itermethod),
+				SuggestedFixes: []analysis.SuggestedFix{{
+					Message: fmt.Sprintf(
+						"Replace %s/%s loop with %s.%s iteration",
+						row.lenmethod, row.atmethod, row.typename, row.itermethod),
+					TextEdits: edits,
+				}},
+			})
+		}
+	}
+	return nil, nil
+}
+
+// -- helpers --
+
+// methodGoVersion reports the version at which the method
+// (pkgpath.recvtype).method appeared in the standard library.
+func methodGoVersion(pkgpath, recvtype, method string) (stdlib.Version, bool) {
+	// TODO(adonovan): opt: this might be inefficient for large packages
+	// like go/types. If so, memoize using a map (and kill two birds with
+	// one stone by also memoizing the 'within' check above).
+	for _, sym := range stdlib.PackageSymbols[pkgpath] {
+		if sym.Kind == stdlib.Method {
+			_, recv, name := sym.SplitMethod()
+			if recv == recvtype && name == method {
+				return sym.Version, true
+			}
+		}
+	}
+	return 0, false
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringsbuilder.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringsbuilder.go
new file mode 100644
index 00000000000000..56d0ba73cc2d19
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringsbuilder.go
@@ -0,0 +1,328 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var StringsBuilderAnalyzer = &analysis.Analyzer{
+	Name: "stringsbuilder",
+	Doc:  analysisinternal.MustExtractDoc(doc, "stringsbuilder"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: stringsbuilder,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#stringbuilder",
+}
+
+// stringsbuilder replaces string += string in a loop by strings.Builder.
+func stringsbuilder(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	// Skip the analyzer in packages where its
+	// fixes would create an import cycle.
+	if within(pass, "strings", "runtime") {
+		return nil, nil
+	}
+
+	var (
+		inspect = pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		index   = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+	)
+
+	// Gather all local string variables that appear on the
+	// LHS of some string += string assignment.
+	candidates := make(map[*types.Var]bool)
+	for curAssign := range inspect.Root().Preorder((*ast.AssignStmt)(nil)) {
+		assign := curAssign.Node().(*ast.AssignStmt)
+		if assign.Tok == token.ADD_ASSIGN && is[*ast.Ident](assign.Lhs[0]) {
+			if v, ok := pass.TypesInfo.Uses[assign.Lhs[0].(*ast.Ident)].(*types.Var); ok &&
+				!typesinternal.IsPackageLevel(v) && // TODO(adonovan): in go1.25, use v.Kind() == types.LocalVar &&
+				types.Identical(v.Type(), builtinString.Type()) {
+				candidates[v] = true
+			}
+		}
+	}
+
+	// Now check each candidate variable's decl and uses.
+nextcand:
+	for v := range candidates {
+		var edits []analysis.TextEdit
+
+		// Check declaration of s:
+		//
+		//    s := expr
+		//    var s [string] [= expr]
+		//
+		// and transform to:
+		//
+		//    var s strings.Builder; s.WriteString(expr)
+		//
+		def, ok := index.Def(v)
+		if !ok {
+			continue
+		}
+		ek, _ := def.ParentEdge()
+		if ek == edge.AssignStmt_Lhs &&
+			len(def.Parent().Node().(*ast.AssignStmt).Lhs) == 1 {
+			// Have: s := expr
+			// => var s strings.Builder; s.WriteString(expr)
+
+			assign := def.Parent().Node().(*ast.AssignStmt)
+
+			// Reject "if s := f(); ..." since in that context
+			// we can't replace the assign with two statements.
+			switch def.Parent().Parent().Node().(type) {
+			case *ast.BlockStmt, *ast.CaseClause, *ast.CommClause:
+				// OK: these are the parts of syntax that
+				// allow unrestricted statement lists.
+			default:
+				continue
+			}
+
+			// Add strings import.
+			prefix, importEdits := refactor.AddImport(
+				pass.TypesInfo, astutil.EnclosingFile(def), "strings", "strings", "Builder", v.Pos())
+			edits = append(edits, importEdits...)
+
+			if isEmptyString(pass.TypesInfo, assign.Rhs[0]) {
+				// s := ""
+				// ---------------------
+				// var s strings.Builder
+				edits = append(edits, analysis.TextEdit{
+					Pos:     assign.Pos(),
+					End:     assign.End(),
+					NewText: fmt.Appendf(nil, "var %[1]s %[2]sBuilder", v.Name(), prefix),
+				})
+
+			} else {
+				// s :=                                 expr
+				// -------------------------------------    -
+				// var s strings.Builder; s.WriteString(expr)
+				edits = append(edits, []analysis.TextEdit{
+					{
+						Pos:     assign.Pos(),
+						End:     assign.Rhs[0].Pos(),
+						NewText: fmt.Appendf(nil, "var %[1]s %[2]sBuilder; %[1]s.WriteString(", v.Name(), prefix),
+					},
+					{
+						Pos:     assign.End(),
+						End:     assign.End(),
+						NewText: []byte(")"),
+					},
+				}...)
+
+			}
+
+		} else if ek == edge.ValueSpec_Names &&
+			len(def.Parent().Node().(*ast.ValueSpec).Names) == 1 {
+			// Have: var s [string] [= expr]
+			// => var s strings.Builder; s.WriteString(expr)
+
+			// Add strings import.
+			prefix, importEdits := refactor.AddImport(
+				pass.TypesInfo, astutil.EnclosingFile(def), "strings", "strings", "Builder", v.Pos())
+			edits = append(edits, importEdits...)
+
+			spec := def.Parent().Node().(*ast.ValueSpec)
+			decl := def.Parent().Parent().Node().(*ast.GenDecl)
+
+			init := spec.Names[0].End() // start of " = expr"
+			if spec.Type != nil {
+				init = spec.Type.End()
+			}
+
+			// var s [string]
+			//      ----------------
+			// var s strings.Builder
+			edits = append(edits, analysis.TextEdit{
+				Pos:     spec.Names[0].End(),
+				End:     init,
+				NewText: fmt.Appendf(nil, " %sBuilder", prefix),
+			})
+
+			if len(spec.Values) > 0 && !isEmptyString(pass.TypesInfo, spec.Values[0]) {
+				// =               expr
+				// ----------------    -
+				// ; s.WriteString(expr)
+				edits = append(edits, []analysis.TextEdit{
+					{
+						Pos:     init,
+						End:     spec.Values[0].Pos(),
+						NewText: fmt.Appendf(nil, "; %s.WriteString(", v.Name()),
+					},
+					{
+						Pos:     decl.End(),
+						End:     decl.End(),
+						NewText: []byte(")"),
+					},
+				}...)
+			} else {
+				// delete "= expr"
+				edits = append(edits, analysis.TextEdit{
+					Pos: init,
+					End: spec.End(),
+				})
+			}
+
+		} else {
+			continue
+		}
+
+		// Check uses of s.
+		//
+		// - All uses of s except the final one must be of the form
+		//
+		//    s += expr
+		//
+		//   Each of these will become s.WriteString(expr).
+		//   At least one of them must be in an intervening loop
+		//   w.r.t. the declaration of s:
+		//
+		//    var s string
+		//    for ... { s += expr }
+		//
+		// - The final use of s must be as an rvalue (e.g. use(s), not &s).
+		//   This will become s.String().
+		//
+		//   Perhaps surprisingly, it is fine for there to be an
+		//   intervening loop or lambda w.r.t. the declaration of s:
+		//
+		//    var s strings.Builder
+		//    for range kSmall { s.WriteString(expr) }
+		//    for range kLarge { use(s.String()) } // called repeatedly
+		//
+		//   Even though that might cause the s.String() operation to be
+		//   executed repeatedly, this is not a deoptimization because,
+		//   by design, (*strings.Builder).String does not allocate.
+		var (
+			numLoopAssigns int             // number of += assignments within a loop
+			loopAssign     *ast.AssignStmt // first += assignment within a loop
+			seenRvalueUse  bool            // => we've seen the sole final use of s as an rvalue
+		)
+		for curUse := range index.Uses(v) {
+			// Strip enclosing parens around Ident.
+			ek, _ := curUse.ParentEdge()
+			for ek == edge.ParenExpr_X {
+				curUse = curUse.Parent()
+				ek, _ = curUse.ParentEdge()
+			}
+
+			// The rvalueUse must be the lexically last use.
+			if seenRvalueUse {
+				continue nextcand
+			}
+
+			// intervening reports whether cur has an ancestor of
+			// one of the given types that is within the scope of v.
+			intervening := func(types ...ast.Node) bool {
+				for cur := range curUse.Enclosing(types...) {
+					if v.Pos() <= cur.Node().Pos() { // in scope of v
+						return true
+					}
+				}
+				return false
+			}
+
+			if ek == edge.AssignStmt_Lhs {
+				assign := curUse.Parent().Node().(*ast.AssignStmt)
+				if assign.Tok != token.ADD_ASSIGN {
+					continue nextcand
+				}
+				// Have: s += expr
+
+				// At least one of the += operations
+				// must appear within a loop.
+				// relative to the declaration of s.
+				if intervening((*ast.ForStmt)(nil), (*ast.RangeStmt)(nil)) {
+					numLoopAssigns++
+					if loopAssign == nil {
+						loopAssign = assign
+					}
+				}
+
+				// s +=          expr
+				//  -------------    -
+				// s.WriteString(expr)
+				edits = append(edits, []analysis.TextEdit{
+					// replace += with .WriteString()
+					{
+						Pos:     assign.TokPos,
+						End:     assign.Rhs[0].Pos(),
+						NewText: []byte(".WriteString("),
+					},
+					// insert ")"
+					{
+						Pos:     assign.End(),
+						End:     assign.End(),
+						NewText: []byte(")"),
+					},
+				}...)
+
+			} else if ek == edge.UnaryExpr_X &&
+				curUse.Parent().Node().(*ast.UnaryExpr).Op == token.AND {
+				// Have: use(&s)
+				continue nextcand // s is used as an lvalue; reject
+
+			} else {
+				// The only possible l-value uses of a string variable
+				// are assignments (s=expr, s+=expr, etc) and &s.
+				// (For strings, we can ignore method calls s.m().)
+				// All other uses are r-values.
+				seenRvalueUse = true
+
+				edits = append(edits, analysis.TextEdit{
+					// insert ".String()"
+					Pos:     curUse.Node().End(),
+					End:     curUse.Node().End(),
+					NewText: []byte(".String()"),
+				})
+			}
+		}
+		if !seenRvalueUse {
+			continue nextcand // no rvalue use; reject
+		}
+		if numLoopAssigns == 0 {
+			continue nextcand // no += in a loop; reject
+		}
+
+		pass.Report(analysis.Diagnostic{
+			Pos:     loopAssign.Pos(),
+			End:     loopAssign.End(),
+			Message: "using string += string in a loop is inefficient",
+			SuggestedFixes: []analysis.SuggestedFix{{
+				Message:   "Replace string += string with strings.Builder",
+				TextEdits: edits,
+			}},
+		})
+	}
+
+	return nil, nil
+}
+
+// isEmptyString reports whether e (a string-typed expression) has constant value "".
+func isEmptyString(info *types.Info, e ast.Expr) bool {
+	tv, ok := info.Types[e]
+	return ok && tv.Value != nil && constant.StringVal(tv.Value) == ""
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringscutprefix.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringscutprefix.go
new file mode 100644
index 00000000000000..9e76f953ed5872
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringscutprefix.go
@@ -0,0 +1,261 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strings"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var StringsCutPrefixAnalyzer = &analysis.Analyzer{
+	Name: "stringscutprefix",
+	Doc:  analysisinternal.MustExtractDoc(doc, "stringscutprefix"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: stringscutprefix,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#stringscutprefix",
+}
+
+// stringscutprefix offers a fix to replace an if statement which
+// calls to the 2 patterns below with strings.CutPrefix or strings.CutSuffix.
+//
+// Patterns:
+//
+//  1. if strings.HasPrefix(s, pre) { use(strings.TrimPrefix(s, pre) }
+//     =>
+//     if after, ok := strings.CutPrefix(s, pre); ok { use(after) }
+//
+//  2. if after := strings.TrimPrefix(s, pre); after != s { use(after) }
+//     =>
+//     if after, ok := strings.CutPrefix(s, pre); ok { use(after) }
+//
+// Similar patterns apply for CutSuffix.
+//
+// The use must occur within the first statement of the block, and the offered fix
+// only replaces the first occurrence of strings.TrimPrefix/TrimSuffix.
+//
+// Variants:
+// - bytes.HasPrefix/HasSuffix usage as pattern 1.
+func stringscutprefix(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	var (
+		inspect = pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		index   = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info    = pass.TypesInfo
+
+		stringsTrimPrefix = index.Object("strings", "TrimPrefix")
+		bytesTrimPrefix   = index.Object("bytes", "TrimPrefix")
+		stringsTrimSuffix = index.Object("strings", "TrimSuffix")
+		bytesTrimSuffix   = index.Object("bytes", "TrimSuffix")
+	)
+	if !index.Used(stringsTrimPrefix, bytesTrimPrefix, stringsTrimSuffix, bytesTrimSuffix) {
+		return nil, nil
+	}
+
+	for curFile := range filesUsing(inspect, pass.TypesInfo, "go1.20") {
+		for curIfStmt := range curFile.Preorder((*ast.IfStmt)(nil)) {
+			ifStmt := curIfStmt.Node().(*ast.IfStmt)
+
+			// pattern1
+			if call, ok := ifStmt.Cond.(*ast.CallExpr); ok && ifStmt.Init == nil && len(ifStmt.Body.List) > 0 {
+
+				obj := typeutil.Callee(info, call)
+				if !typesinternal.IsFunctionNamed(obj, "strings", "HasPrefix", "HasSuffix") &&
+					!typesinternal.IsFunctionNamed(obj, "bytes", "HasPrefix", "HasSuffix") {
+					continue
+				}
+				isPrefix := strings.HasSuffix(obj.Name(), "Prefix")
+
+				// Replace the first occurrence of strings.TrimPrefix(s, pre) in the first statement only,
+				// but not later statements in case s or pre are modified by intervening logic (ditto Suffix).
+				firstStmt := curIfStmt.Child(ifStmt.Body).Child(ifStmt.Body.List[0])
+				for curCall := range firstStmt.Preorder((*ast.CallExpr)(nil)) {
+					call1 := curCall.Node().(*ast.CallExpr)
+					obj1 := typeutil.Callee(info, call1)
+					// bytesTrimPrefix or stringsTrimPrefix might be nil if the file doesn't import it,
+					// so we need to ensure the obj1 is not nil otherwise the call1 is not TrimPrefix and cause a panic (ditto Suffix).
+					if obj1 == nil ||
+						obj1 != stringsTrimPrefix && obj1 != bytesTrimPrefix &&
+							obj1 != stringsTrimSuffix && obj1 != bytesTrimSuffix {
+						continue
+					}
+
+					isPrefix1 := strings.HasSuffix(obj1.Name(), "Prefix")
+					var cutFuncName, varName, message, fixMessage string
+					if isPrefix && isPrefix1 {
+						cutFuncName = "CutPrefix"
+						varName = "after"
+						message = "HasPrefix + TrimPrefix can be simplified to CutPrefix"
+						fixMessage = "Replace HasPrefix/TrimPrefix with CutPrefix"
+					} else if !isPrefix && !isPrefix1 {
+						cutFuncName = "CutSuffix"
+						varName = "before"
+						message = "HasSuffix + TrimSuffix can be simplified to CutSuffix"
+						fixMessage = "Replace HasSuffix/TrimSuffix with CutSuffix"
+					} else {
+						continue
+					}
+
+					// Have: if strings.HasPrefix(s0, pre0) { ...strings.TrimPrefix(s, pre)... } (ditto Suffix)
+					var (
+						s0   = call.Args[0]
+						pre0 = call.Args[1]
+						s    = call1.Args[0]
+						pre  = call1.Args[1]
+					)
+
+					// check whether the obj1 uses the exact the same argument with strings.HasPrefix
+					// shadow variables won't be valid because we only access the first statement (ditto Suffix).
+					if astutil.EqualSyntax(s0, s) && astutil.EqualSyntax(pre0, pre) {
+						after := refactor.FreshName(info.Scopes[ifStmt], ifStmt.Pos(), varName)
+						prefix, importEdits := refactor.AddImport(
+							info,
+							curFile.Node().(*ast.File),
+							obj1.Pkg().Name(),
+							obj1.Pkg().Path(),
+							cutFuncName,
+							call.Pos(),
+						)
+						okVarName := refactor.FreshName(info.Scopes[ifStmt], ifStmt.Pos(), "ok")
+						pass.Report(analysis.Diagnostic{
+							// highlight at HasPrefix call (ditto Suffix).
+							Pos:     call.Pos(),
+							End:     call.End(),
+							Message: message,
+							SuggestedFixes: []analysis.SuggestedFix{{
+								Message: fixMessage,
+								// if              strings.HasPrefix(s, pre)     { use(strings.TrimPrefix(s, pre)) }
+								//    ------------ -----------------        -----      --------------------------
+								// if after, ok := strings.CutPrefix(s, pre); ok { use(after)                      }
+								// (ditto Suffix)
+								TextEdits: append(importEdits, []analysis.TextEdit{
+									{
+										Pos:     call.Fun.Pos(),
+										End:     call.Fun.Pos(),
+										NewText: fmt.Appendf(nil, "%s, %s :=", after, okVarName),
+									},
+									{
+										Pos:     call.Fun.Pos(),
+										End:     call.Fun.End(),
+										NewText: fmt.Appendf(nil, "%s%s", prefix, cutFuncName),
+									},
+									{
+										Pos:     call.End(),
+										End:     call.End(),
+										NewText: fmt.Appendf(nil, "; %s ", okVarName),
+									},
+									{
+										Pos:     call1.Pos(),
+										End:     call1.End(),
+										NewText: []byte(after),
+									},
+								}...),
+							}}},
+						)
+						break
+					}
+				}
+			}
+
+			// pattern2
+			if bin, ok := ifStmt.Cond.(*ast.BinaryExpr); ok &&
+				bin.Op == token.NEQ &&
+				ifStmt.Init != nil &&
+				isSimpleAssign(ifStmt.Init) {
+				assign := ifStmt.Init.(*ast.AssignStmt)
+				if call, ok := assign.Rhs[0].(*ast.CallExpr); ok && assign.Tok == token.DEFINE {
+					lhs := assign.Lhs[0]
+					obj := typeutil.Callee(info, call)
+
+					if obj == nil ||
+						obj != stringsTrimPrefix && obj != bytesTrimPrefix && obj != stringsTrimSuffix && obj != bytesTrimSuffix {
+						continue
+					}
+
+					isPrefix1 := strings.HasSuffix(obj.Name(), "Prefix")
+					var cutFuncName, message, fixMessage string
+					if isPrefix1 {
+						cutFuncName = "CutPrefix"
+						message = "TrimPrefix can be simplified to CutPrefix"
+						fixMessage = "Replace TrimPrefix with CutPrefix"
+					} else {
+						cutFuncName = "CutSuffix"
+						message = "TrimSuffix can be simplified to CutSuffix"
+						fixMessage = "Replace TrimSuffix with CutSuffix"
+					}
+
+					if astutil.EqualSyntax(lhs, bin.X) && astutil.EqualSyntax(call.Args[0], bin.Y) ||
+						(astutil.EqualSyntax(lhs, bin.Y) && astutil.EqualSyntax(call.Args[0], bin.X)) {
+						okVarName := refactor.FreshName(info.Scopes[ifStmt], ifStmt.Pos(), "ok")
+						// Have one of:
+						//   if rest := TrimPrefix(s, prefix); rest != s { (ditto Suffix)
+						//   if rest := TrimPrefix(s, prefix); s != rest { (ditto Suffix)
+
+						// We use AddImport not to add an import (since it exists already)
+						// but to compute the correct prefix in the dot-import case.
+						prefix, importEdits := refactor.AddImport(
+							info,
+							curFile.Node().(*ast.File),
+							obj.Pkg().Name(),
+							obj.Pkg().Path(),
+							cutFuncName,
+							call.Pos(),
+						)
+
+						pass.Report(analysis.Diagnostic{
+							// highlight from the init and the condition end.
+							Pos:     ifStmt.Init.Pos(),
+							End:     ifStmt.Cond.End(),
+							Message: message,
+							SuggestedFixes: []analysis.SuggestedFix{{
+								Message: fixMessage,
+								// if x     := strings.TrimPrefix(s, pre); x != s ...
+								//     ----            ----------          ------
+								// if x, ok := strings.CutPrefix (s, pre); ok     ...
+								// (ditto Suffix)
+								TextEdits: append(importEdits, []analysis.TextEdit{
+									{
+										Pos:     assign.Lhs[0].End(),
+										End:     assign.Lhs[0].End(),
+										NewText: fmt.Appendf(nil, ", %s", okVarName),
+									},
+									{
+										Pos:     call.Fun.Pos(),
+										End:     call.Fun.End(),
+										NewText: fmt.Appendf(nil, "%s%s", prefix, cutFuncName),
+									},
+									{
+										Pos:     ifStmt.Cond.Pos(),
+										End:     ifStmt.Cond.End(),
+										NewText: []byte(okVarName),
+									},
+								}...),
+							}},
+						})
+					}
+				}
+			}
+		}
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringsseq.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringsseq.go
new file mode 100644
index 00000000000000..ef2b5463640e6f
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/stringsseq.go
@@ -0,0 +1,145 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var StringsSeqAnalyzer = &analysis.Analyzer{
+	Name: "stringsseq",
+	Doc:  analysisinternal.MustExtractDoc(doc, "stringsseq"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: stringsseq,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#stringsseq",
+}
+
+// stringsseq offers a fix to replace a call to strings.Split with
+// SplitSeq or strings.Fields with FieldsSeq
+// when it is the operand of a range loop, either directly:
+//
+//	for _, line := range strings.Split() {...}
+//
+// or indirectly, if the variable's sole use is the range statement:
+//
+//	lines := strings.Split()
+//	for _, line := range lines {...}
+//
+// Variants:
+// - bytes.SplitSeq
+// - bytes.FieldsSeq
+func stringsseq(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	var (
+		inspect = pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+		index   = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info    = pass.TypesInfo
+
+		stringsSplit  = index.Object("strings", "Split")
+		stringsFields = index.Object("strings", "Fields")
+		bytesSplit    = index.Object("bytes", "Split")
+		bytesFields   = index.Object("bytes", "Fields")
+	)
+	if !index.Used(stringsSplit, stringsFields, bytesSplit, bytesFields) {
+		return nil, nil
+	}
+
+	for curFile := range filesUsing(inspect, info, "go1.24") {
+		for curRange := range curFile.Preorder((*ast.RangeStmt)(nil)) {
+			rng := curRange.Node().(*ast.RangeStmt)
+
+			// Reject "for i, line := ..." since SplitSeq is not an iter.Seq2.
+			// (We require that i is blank.)
+			if id, ok := rng.Key.(*ast.Ident); ok && id.Name != "_" {
+				continue
+			}
+
+			// Find the call operand of the range statement,
+			// whether direct or indirect.
+			call, ok := rng.X.(*ast.CallExpr)
+			if !ok {
+				if id, ok := rng.X.(*ast.Ident); ok {
+					if v, ok := info.Uses[id].(*types.Var); ok {
+						if ek, idx := curRange.ParentEdge(); ek == edge.BlockStmt_List && idx > 0 {
+							curPrev, _ := curRange.PrevSibling()
+							if assign, ok := curPrev.Node().(*ast.AssignStmt); ok &&
+								assign.Tok == token.DEFINE &&
+								len(assign.Lhs) == 1 &&
+								len(assign.Rhs) == 1 &&
+								info.Defs[assign.Lhs[0].(*ast.Ident)] == v &&
+								soleUseIs(index, v, id) {
+								// Have:
+								//    lines := ...
+								//    for _, line := range lines {...}
+								// and no other uses of lines.
+								call, _ = assign.Rhs[0].(*ast.CallExpr)
+							}
+						}
+					}
+				}
+			}
+
+			if call != nil {
+				var edits []analysis.TextEdit
+				if rng.Key != nil {
+					// Delete (blank) RangeStmt.Key:
+					//  for _, line := -> for line :=
+					//  for _, _    := -> for
+					//  for _       := -> for
+					end := rng.Range
+					if rng.Value != nil {
+						end = rng.Value.Pos()
+					}
+					edits = append(edits, analysis.TextEdit{
+						Pos: rng.Key.Pos(),
+						End: end,
+					})
+				}
+
+				sel, ok := call.Fun.(*ast.SelectorExpr)
+				if !ok {
+					continue
+				}
+
+				switch obj := typeutil.Callee(info, call); obj {
+				case stringsSplit, stringsFields, bytesSplit, bytesFields:
+					oldFnName := obj.Name()
+					seqFnName := fmt.Sprintf("%sSeq", oldFnName)
+					pass.Report(analysis.Diagnostic{
+						Pos:     sel.Pos(),
+						End:     sel.End(),
+						Message: fmt.Sprintf("Ranging over %s is more efficient", seqFnName),
+						SuggestedFixes: []analysis.SuggestedFix{{
+							Message: fmt.Sprintf("Replace %s with %s", oldFnName, seqFnName),
+							TextEdits: append(edits, analysis.TextEdit{
+								Pos:     sel.Sel.Pos(),
+								End:     sel.Sel.End(),
+								NewText: []byte(seqFnName)}),
+						}},
+					})
+				}
+			}
+		}
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/testingcontext.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/testingcontext.go
new file mode 100644
index 00000000000000..558cf142dd6ce9
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/testingcontext.go
@@ -0,0 +1,253 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/ast/edge"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var TestingContextAnalyzer = &analysis.Analyzer{
+	Name: "testingcontext",
+	Doc:  analysisinternal.MustExtractDoc(doc, "testingcontext"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: testingContext,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#testingcontext",
+}
+
+// The testingContext pass replaces calls to context.WithCancel from within
+// tests to a use of testing.{T,B,F}.Context(), added in Go 1.24.
+//
+// Specifically, the testingContext pass suggests to replace:
+//
+//	ctx, cancel := context.WithCancel(context.Background()) // or context.TODO
+//	defer cancel()
+//
+// with:
+//
+//	ctx := t.Context()
+//
+// provided:
+//
+//   - ctx and cancel are declared by the assignment
+//   - the deferred call is the only use of cancel
+//   - the call is within a test or subtest function
+//   - the relevant testing.{T,B,F} is named and not shadowed at the call
+func testingContext(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	var (
+		index = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info  = pass.TypesInfo
+
+		contextWithCancel = index.Object("context", "WithCancel")
+	)
+
+calls:
+	for cur := range index.Calls(contextWithCancel) {
+		call := cur.Node().(*ast.CallExpr)
+		// Have: context.WithCancel(...)
+
+		arg, ok := call.Args[0].(*ast.CallExpr)
+		if !ok {
+			continue
+		}
+		if !typesinternal.IsFunctionNamed(typeutil.Callee(info, arg), "context", "Background", "TODO") {
+			continue
+		}
+		// Have: context.WithCancel(context.{Background,TODO}())
+
+		parent := cur.Parent()
+		assign, ok := parent.Node().(*ast.AssignStmt)
+		if !ok || assign.Tok != token.DEFINE {
+			continue
+		}
+		// Have: a, b := context.WithCancel(context.{Background,TODO}())
+
+		// Check that both a and b are declared, not redeclarations.
+		var lhs []types.Object
+		for _, expr := range assign.Lhs {
+			id, ok := expr.(*ast.Ident)
+			if !ok {
+				continue calls
+			}
+			obj, ok := info.Defs[id]
+			if !ok {
+				continue calls
+			}
+			lhs = append(lhs, obj)
+		}
+
+		next, ok := parent.NextSibling()
+		if !ok {
+			continue
+		}
+		defr, ok := next.Node().(*ast.DeferStmt)
+		if !ok {
+			continue
+		}
+		deferId, ok := defr.Call.Fun.(*ast.Ident)
+		if !ok || !soleUseIs(index, lhs[1], deferId) {
+			continue // b is used elsewhere
+		}
+		// Have:
+		// a, b := context.WithCancel(context.{Background,TODO}())
+		// defer b()
+
+		// Check that we are in a test func.
+		var testObj types.Object // relevant testing.{T,B,F}, or nil
+		if curFunc, ok := enclosingFunc(cur); ok {
+			switch n := curFunc.Node().(type) {
+			case *ast.FuncLit:
+				if ek, idx := curFunc.ParentEdge(); ek == edge.CallExpr_Args && idx == 1 {
+					// Have: call(..., func(...) { ...context.WithCancel(...)... })
+					obj := typeutil.Callee(info, curFunc.Parent().Node().(*ast.CallExpr))
+					if (typesinternal.IsMethodNamed(obj, "testing", "T", "Run") ||
+						typesinternal.IsMethodNamed(obj, "testing", "B", "Run")) &&
+						len(n.Type.Params.List[0].Names) == 1 {
+
+						// Have tb.Run(..., func(..., tb *testing.[TB]) { ...context.WithCancel(...)... }
+						testObj = info.Defs[n.Type.Params.List[0].Names[0]]
+					}
+				}
+
+			case *ast.FuncDecl:
+				testObj = isTestFn(info, n)
+			}
+		}
+		if testObj != nil && fileUses(info, astutil.EnclosingFile(cur), "go1.24") {
+			// Have a test function. Check that we can resolve the relevant
+			// testing.{T,B,F} at the current position.
+			if _, obj := lhs[0].Parent().LookupParent(testObj.Name(), lhs[0].Pos()); obj == testObj {
+				pass.Report(analysis.Diagnostic{
+					Pos:     call.Fun.Pos(),
+					End:     call.Fun.End(),
+					Message: fmt.Sprintf("context.WithCancel can be modernized using %s.Context", testObj.Name()),
+					SuggestedFixes: []analysis.SuggestedFix{{
+						Message: fmt.Sprintf("Replace context.WithCancel with %s.Context", testObj.Name()),
+						TextEdits: []analysis.TextEdit{{
+							Pos:     assign.Pos(),
+							End:     defr.End(),
+							NewText: fmt.Appendf(nil, "%s := %s.Context()", lhs[0].Name(), testObj.Name()),
+						}},
+					}},
+				})
+			}
+		}
+	}
+	return nil, nil
+}
+
+// soleUseIs reports whether id is the sole Ident that uses obj.
+// (It returns false if there were no uses of obj.)
+func soleUseIs(index *typeindex.Index, obj types.Object, id *ast.Ident) bool {
+	empty := true
+	for use := range index.Uses(obj) {
+		empty = false
+		if use.Node() != id {
+			return false
+		}
+	}
+	return !empty
+}
+
+// isTestFn checks whether fn is a test function (TestX, BenchmarkX, FuzzX),
+// returning the corresponding types.Object of the *testing.{T,B,F} argument.
+// Returns nil if fn is a test function, but the testing.{T,B,F} argument is
+// unnamed (or _).
+//
+// TODO(rfindley): consider handling the case of an unnamed argument, by adding
+// an edit to give the argument a name.
+//
+// Adapted from go/analysis/passes/tests.
+// TODO(rfindley): consider refactoring to share logic.
+func isTestFn(info *types.Info, fn *ast.FuncDecl) types.Object {
+	// Want functions with 0 results and 1 parameter.
+	if fn.Type.Results != nil && len(fn.Type.Results.List) > 0 ||
+		fn.Type.Params == nil ||
+		len(fn.Type.Params.List) != 1 ||
+		len(fn.Type.Params.List[0].Names) != 1 {
+
+		return nil
+	}
+
+	prefix := testKind(fn.Name.Name)
+	if prefix == "" {
+		return nil
+	}
+
+	if tparams := fn.Type.TypeParams; tparams != nil && len(tparams.List) > 0 {
+		return nil // test functions must not be generic
+	}
+
+	obj := info.Defs[fn.Type.Params.List[0].Names[0]]
+	if obj == nil {
+		return nil // e.g. _ *testing.T
+	}
+
+	var name string
+	switch prefix {
+	case "Test":
+		name = "T"
+	case "Benchmark":
+		name = "B"
+	case "Fuzz":
+		name = "F"
+	}
+
+	if !typesinternal.IsPointerToNamed(obj.Type(), "testing", name) {
+		return nil
+	}
+	return obj
+}
+
+// testKind returns "Test", "Benchmark", or "Fuzz" if name is a valid resp.
+// test, benchmark, or fuzz function name. Otherwise, isTestName returns "".
+//
+// Adapted from go/analysis/passes/tests.isTestName.
+func testKind(name string) string {
+	var prefix string
+	switch {
+	case strings.HasPrefix(name, "Test"):
+		prefix = "Test"
+	case strings.HasPrefix(name, "Benchmark"):
+		prefix = "Benchmark"
+	case strings.HasPrefix(name, "Fuzz"):
+		prefix = "Fuzz"
+	}
+	if prefix == "" {
+		return ""
+	}
+	suffix := name[len(prefix):]
+	if len(suffix) == 0 {
+		// "Test" is ok.
+		return prefix
+	}
+	r, _ := utf8.DecodeRuneInString(suffix)
+	if unicode.IsLower(r) {
+		return ""
+	}
+	return prefix
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/waitgroup.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/waitgroup.go
new file mode 100644
index 00000000000000..b890f334ba168b
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/waitgroup.go
@@ -0,0 +1,175 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package modernize
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/printer"
+	"slices"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/analysisinternal"
+	"golang.org/x/tools/internal/analysisinternal/generated"
+	typeindexanalyzer "golang.org/x/tools/internal/analysisinternal/typeindex"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/refactor"
+	"golang.org/x/tools/internal/typesinternal/typeindex"
+)
+
+var WaitGroupAnalyzer = &analysis.Analyzer{
+	Name: "waitgroup",
+	Doc:  analysisinternal.MustExtractDoc(doc, "waitgroup"),
+	Requires: []*analysis.Analyzer{
+		generated.Analyzer,
+		inspect.Analyzer,
+		typeindexanalyzer.Analyzer,
+	},
+	Run: waitgroup,
+	URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize#waitgroup",
+}
+
+// The waitgroup pass replaces old more complex code with
+// go1.25 added API WaitGroup.Go.
+//
+// Patterns:
+//
+//  1. wg.Add(1); go func() { defer wg.Done(); ... }()
+//     =>
+//     wg.Go(go func() { ... })
+//
+//  2. wg.Add(1); go func() { ...; wg.Done() }()
+//     =>
+//     wg.Go(go func() { ... })
+//
+// The wg.Done must occur within the first statement of the block in a
+// defer format or last statement of the block, and the offered fix
+// only removes the first/last wg.Done call. It doesn't fix existing
+// wrong usage of sync.WaitGroup.
+//
+// The use of WaitGroup.Go in pattern 1 implicitly introduces a
+// 'defer', which may change the behavior in the case of panic from
+// the "..." logic. In this instance, the change is safe: before and
+// after the transformation, an unhandled panic inevitably results in
+// a fatal crash. The fact that the transformed code calls wg.Done()
+// before the crash doesn't materially change anything. (If Done had
+// other effects, or blocked, or if WaitGroup.Go propagated panics
+// from child to parent goroutine, the argument would be different.)
+func waitgroup(pass *analysis.Pass) (any, error) {
+	skipGenerated(pass)
+
+	var (
+		index             = pass.ResultOf[typeindexanalyzer.Analyzer].(*typeindex.Index)
+		info              = pass.TypesInfo
+		syncWaitGroupAdd  = index.Selection("sync", "WaitGroup", "Add")
+		syncWaitGroupDone = index.Selection("sync", "WaitGroup", "Done")
+	)
+	if !index.Used(syncWaitGroupDone) {
+		return nil, nil
+	}
+
+	for curAddCall := range index.Calls(syncWaitGroupAdd) {
+		// Extract receiver from wg.Add call.
+		addCall := curAddCall.Node().(*ast.CallExpr)
+		if !isIntLiteral(info, addCall.Args[0], 1) {
+			continue // not a call to wg.Add(1)
+		}
+		// Inv: the Args[0] check ensures addCall is not of
+		// the form sync.WaitGroup.Add(&wg, 1).
+		addCallRecv := ast.Unparen(addCall.Fun).(*ast.SelectorExpr).X
+
+		// Following statement must be go func() { ... } ().
+		curAddStmt := curAddCall.Parent()
+		if !is[*ast.ExprStmt](curAddStmt.Node()) {
+			continue // unnecessary parens?
+		}
+		curNext, ok := curAddCall.Parent().NextSibling()
+		if !ok {
+			continue // no successor
+		}
+		goStmt, ok := curNext.Node().(*ast.GoStmt)
+		if !ok {
+			continue // not a go stmt
+		}
+		lit, ok := goStmt.Call.Fun.(*ast.FuncLit)
+		if !ok || len(goStmt.Call.Args) != 0 {
+			continue // go argument is not func(){...}()
+		}
+		list := lit.Body.List
+		if len(list) == 0 {
+			continue
+		}
+
+		// Body must start with "defer wg.Done()" or end with "wg.Done()".
+		var doneStmt ast.Stmt
+		if deferStmt, ok := list[0].(*ast.DeferStmt); ok &&
+			typeutil.Callee(info, deferStmt.Call) == syncWaitGroupDone &&
+			astutil.EqualSyntax(ast.Unparen(deferStmt.Call.Fun).(*ast.SelectorExpr).X, addCallRecv) {
+			doneStmt = deferStmt // "defer wg.Done()"
+
+		} else if lastStmt, ok := list[len(list)-1].(*ast.ExprStmt); ok {
+			if doneCall, ok := lastStmt.X.(*ast.CallExpr); ok &&
+				typeutil.Callee(info, doneCall) == syncWaitGroupDone &&
+				astutil.EqualSyntax(ast.Unparen(doneCall.Fun).(*ast.SelectorExpr).X, addCallRecv) {
+				doneStmt = lastStmt // "wg.Done()"
+			}
+		}
+		if doneStmt == nil {
+			continue
+		}
+		curDoneStmt, ok := curNext.FindNode(doneStmt)
+		if !ok {
+			panic("can't find Cursor for 'done' statement")
+		}
+
+		file := astutil.EnclosingFile(curAddCall)
+		if !fileUses(info, file, "go1.25") {
+			continue
+		}
+		tokFile := pass.Fset.File(file.Pos())
+
+		var addCallRecvText bytes.Buffer
+		err := printer.Fprint(&addCallRecvText, pass.Fset, addCallRecv)
+		if err != nil {
+			continue // error getting text for the edit
+		}
+
+		pass.Report(analysis.Diagnostic{
+			Pos:     addCall.Pos(),
+			End:     goStmt.End(),
+			Message: "Goroutine creation can be simplified using WaitGroup.Go",
+			SuggestedFixes: []analysis.SuggestedFix{{
+				Message: "Simplify by using WaitGroup.Go",
+				TextEdits: slices.Concat(
+					// delete "wg.Add(1)"
+					refactor.DeleteStmt(tokFile, curAddStmt),
+					// delete "wg.Done()" or "defer wg.Done()"
+					refactor.DeleteStmt(tokFile, curDoneStmt),
+					[]analysis.TextEdit{
+						// go    func()
+						// ------
+						// wg.Go(func()
+						{
+							Pos:     goStmt.Pos(),
+							End:     goStmt.Call.Pos(),
+							NewText: fmt.Appendf(nil, "%s.Go(", addCallRecvText.String()),
+						},
+						// ... }()
+						//      -
+						// ... } )
+						{
+							Pos: goStmt.Call.Lparen,
+							End: goStmt.Call.Rparen,
+						},
+					},
+				),
+			}},
+		})
+	}
+	return nil, nil
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/enclosing.go b/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/enclosing.go
new file mode 100644
index 00000000000000..0fb4e7eea81af7
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/enclosing.go
@@ -0,0 +1,663 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package astutil
+
+// This file defines utilities for working with source positions.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"sort"
+)
+
+// PathEnclosingInterval returns the node that encloses the source
+// interval [start, end), and all its ancestors up to the AST root.
+//
+// The definition of "enclosing" used by this function considers
+// additional whitespace abutting a node to be enclosed by it.
+// In this example:
+//
+//	z := x + y // add them
+//	     <-A->
+//	    <----B----->
+//
+// the ast.BinaryExpr(+) node is considered to enclose interval B
+// even though its [Pos()..End()) is actually only interval A.
+// This behaviour makes user interfaces more tolerant of imperfect
+// input.
+//
+// This function treats tokens as nodes, though they are not included
+// in the result. e.g. PathEnclosingInterval("+") returns the
+// enclosing ast.BinaryExpr("x + y").
+//
+// If start==end, the 1-char interval following start is used instead.
+//
+// The 'exact' result is true if the interval contains only path[0]
+// and perhaps some adjacent whitespace.  It is false if the interval
+// overlaps multiple children of path[0], or if it contains only
+// interior whitespace of path[0].
+// In this example:
+//
+//	z := x + y // add them
+//	  <--C-->     <---E-->
+//	    ^
+//	    D
+//
+// intervals C, D and E are inexact.  C is contained by the
+// z-assignment statement, because it spans three of its children (:=,
+// x, +).  So too is the 1-char interval D, because it contains only
+// interior whitespace of the assignment.  E is considered interior
+// whitespace of the BlockStmt containing the assignment.
+//
+// The resulting path is never empty; it always contains at least the
+// 'root' *ast.File.  Ideally PathEnclosingInterval would reject
+// intervals that lie wholly or partially outside the range of the
+// file, but unfortunately ast.File records only the token.Pos of
+// the 'package' keyword, but not of the start of the file itself.
+func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool) {
+	// fmt.Printf("EnclosingInterval %d %d\n", start, end) // debugging
+
+	// Precondition: node.[Pos..End) and adjoining whitespace contain [start, end).
+	var visit func(node ast.Node) bool
+	visit = func(node ast.Node) bool {
+		path = append(path, node)
+
+		nodePos := node.Pos()
+		nodeEnd := node.End()
+
+		// fmt.Printf("visit(%T, %d, %d)\n", node, nodePos, nodeEnd) // debugging
+
+		// Intersect [start, end) with interval of node.
+		if start < nodePos {
+			start = nodePos
+		}
+		if end > nodeEnd {
+			end = nodeEnd
+		}
+
+		// Find sole child that contains [start, end).
+		children := childrenOf(node)
+		l := len(children)
+		for i, child := range children {
+			// [childPos, childEnd) is unaugmented interval of child.
+			childPos := child.Pos()
+			childEnd := child.End()
+
+			// [augPos, augEnd) is whitespace-augmented interval of child.
+			augPos := childPos
+			augEnd := childEnd
+			if i > 0 {
+				augPos = children[i-1].End() // start of preceding whitespace
+			}
+			if i < l-1 {
+				nextChildPos := children[i+1].Pos()
+				// Does [start, end) lie between child and next child?
+				if start >= augEnd && end <= nextChildPos {
+					return false // inexact match
+				}
+				augEnd = nextChildPos // end of following whitespace
+			}
+
+			// fmt.Printf("\tchild %d: [%d..%d)\tcontains interval [%d..%d)?\n",
+			// 	i, augPos, augEnd, start, end) // debugging
+
+			// Does augmented child strictly contain [start, end)?
+			if augPos <= start && end <= augEnd {
+				if is[tokenNode](child) {
+					return true
+				}
+
+				// childrenOf elides the FuncType node beneath FuncDecl.
+				// Add it back here for TypeParams, Params, Results,
+				// all FieldLists). But we don't add it back for the "func" token
+				// even though it is the tree at FuncDecl.Type.Func.
+				if decl, ok := node.(*ast.FuncDecl); ok {
+					if fields, ok := child.(*ast.FieldList); ok && fields != decl.Recv {
+						path = append(path, decl.Type)
+					}
+				}
+
+				return visit(child)
+			}
+
+			// Does [start, end) overlap multiple children?
+			// i.e. left-augmented child contains start
+			// but LR-augmented child does not contain end.
+			if start < childEnd && end > augEnd {
+				break
+			}
+		}
+
+		// No single child contained [start, end),
+		// so node is the result.  Is it exact?
+
+		// (It's tempting to put this condition before the
+		// child loop, but it gives the wrong result in the
+		// case where a node (e.g. ExprStmt) and its sole
+		// child have equal intervals.)
+		if start == nodePos && end == nodeEnd {
+			return true // exact match
+		}
+
+		return false // inexact: overlaps multiple children
+	}
+
+	// Ensure [start,end) is nondecreasing.
+	if start > end {
+		start, end = end, start
+	}
+
+	if start < root.End() && end > root.Pos() {
+		if start == end {
+			end = start + 1 // empty interval => interval of size 1
+		}
+		exact = visit(root)
+
+		// Reverse the path:
+		for i, l := 0, len(path); i < l/2; i++ {
+			path[i], path[l-1-i] = path[l-1-i], path[i]
+		}
+	} else {
+		// Selection lies within whitespace preceding the
+		// first (or following the last) declaration in the file.
+		// The result nonetheless always includes the ast.File.
+		path = append(path, root)
+	}
+
+	return
+}
+
+// tokenNode is a dummy implementation of ast.Node for a single token.
+// They are used transiently by PathEnclosingInterval but never escape
+// this package.
+type tokenNode struct {
+	pos token.Pos
+	end token.Pos
+}
+
+func (n tokenNode) Pos() token.Pos {
+	return n.pos
+}
+
+func (n tokenNode) End() token.Pos {
+	return n.end
+}
+
+func tok(pos token.Pos, len int) ast.Node {
+	return tokenNode{pos, pos + token.Pos(len)}
+}
+
+// childrenOf returns the direct non-nil children of ast.Node n.
+// It may include fake ast.Node implementations for bare tokens.
+// it is not safe to call (e.g.) ast.Walk on such nodes.
+func childrenOf(n ast.Node) []ast.Node {
+	var children []ast.Node
+
+	// First add nodes for all true subtrees.
+	ast.Inspect(n, func(node ast.Node) bool {
+		if node == n { // push n
+			return true // recur
+		}
+		if node != nil { // push child
+			children = append(children, node)
+		}
+		return false // no recursion
+	})
+
+	// TODO(adonovan): be more careful about missing (!Pos.Valid)
+	// tokens in trees produced from invalid input.
+
+	// Then add fake Nodes for bare tokens.
+	switch n := n.(type) {
+	case *ast.ArrayType:
+		children = append(children,
+			tok(n.Lbrack, len("[")),
+			tok(n.Elt.End(), len("]")))
+
+	case *ast.AssignStmt:
+		children = append(children,
+			tok(n.TokPos, len(n.Tok.String())))
+
+	case *ast.BasicLit:
+		children = append(children,
+			tok(n.ValuePos, len(n.Value)))
+
+	case *ast.BinaryExpr:
+		children = append(children, tok(n.OpPos, len(n.Op.String())))
+
+	case *ast.BlockStmt:
+		if n.Lbrace.IsValid() {
+			children = append(children, tok(n.Lbrace, len("{")))
+		}
+		if n.Rbrace.IsValid() {
+			children = append(children, tok(n.Rbrace, len("}")))
+		}
+
+	case *ast.BranchStmt:
+		children = append(children,
+			tok(n.TokPos, len(n.Tok.String())))
+
+	case *ast.CallExpr:
+		children = append(children,
+			tok(n.Lparen, len("(")),
+			tok(n.Rparen, len(")")))
+		if n.Ellipsis != 0 {
+			children = append(children, tok(n.Ellipsis, len("...")))
+		}
+
+	case *ast.CaseClause:
+		if n.List == nil {
+			children = append(children,
+				tok(n.Case, len("default")))
+		} else {
+			children = append(children,
+				tok(n.Case, len("case")))
+		}
+		children = append(children, tok(n.Colon, len(":")))
+
+	case *ast.ChanType:
+		switch n.Dir {
+		case ast.RECV:
+			children = append(children, tok(n.Begin, len("<-chan")))
+		case ast.SEND:
+			children = append(children, tok(n.Begin, len("chan<-")))
+		case ast.RECV | ast.SEND:
+			children = append(children, tok(n.Begin, len("chan")))
+		}
+
+	case *ast.CommClause:
+		if n.Comm == nil {
+			children = append(children,
+				tok(n.Case, len("default")))
+		} else {
+			children = append(children,
+				tok(n.Case, len("case")))
+		}
+		children = append(children, tok(n.Colon, len(":")))
+
+	case *ast.Comment:
+		// nop
+
+	case *ast.CommentGroup:
+		// nop
+
+	case *ast.CompositeLit:
+		children = append(children,
+			tok(n.Lbrace, len("{")),
+			tok(n.Rbrace, len("{")))
+
+	case *ast.DeclStmt:
+		// nop
+
+	case *ast.DeferStmt:
+		children = append(children,
+			tok(n.Defer, len("defer")))
+
+	case *ast.Ellipsis:
+		children = append(children,
+			tok(n.Ellipsis, len("...")))
+
+	case *ast.EmptyStmt:
+		// nop
+
+	case *ast.ExprStmt:
+		// nop
+
+	case *ast.Field:
+		// TODO(adonovan): Field.{Doc,Comment,Tag}?
+
+	case *ast.FieldList:
+		if n.Opening.IsValid() {
+			children = append(children, tok(n.Opening, len("(")))
+		}
+		if n.Closing.IsValid() {
+			children = append(children, tok(n.Closing, len(")")))
+		}
+
+	case *ast.File:
+		// TODO test: Doc
+		children = append(children,
+			tok(n.Package, len("package")))
+
+	case *ast.ForStmt:
+		children = append(children,
+			tok(n.For, len("for")))
+
+	case *ast.FuncDecl:
+		// TODO(adonovan): FuncDecl.Comment?
+
+		// Uniquely, FuncDecl breaks the invariant that
+		// preorder traversal yields tokens in lexical order:
+		// in fact, FuncDecl.Recv precedes FuncDecl.Type.Func.
+		//
+		// As a workaround, we inline the case for FuncType
+		// here and order things correctly.
+		// We also need to insert the elided FuncType just
+		// before the 'visit' recursion.
+		//
+		children = nil // discard ast.Walk(FuncDecl) info subtrees
+		children = append(children, tok(n.Type.Func, len("func")))
+		if n.Recv != nil {
+			children = append(children, n.Recv)
+		}
+		children = append(children, n.Name)
+		if tparams := n.Type.TypeParams; tparams != nil {
+			children = append(children, tparams)
+		}
+		if n.Type.Params != nil {
+			children = append(children, n.Type.Params)
+		}
+		if n.Type.Results != nil {
+			children = append(children, n.Type.Results)
+		}
+		if n.Body != nil {
+			children = append(children, n.Body)
+		}
+
+	case *ast.FuncLit:
+		// nop
+
+	case *ast.FuncType:
+		if n.Func != 0 {
+			children = append(children,
+				tok(n.Func, len("func")))
+		}
+
+	case *ast.GenDecl:
+		children = append(children,
+			tok(n.TokPos, len(n.Tok.String())))
+		if n.Lparen != 0 {
+			children = append(children,
+				tok(n.Lparen, len("(")),
+				tok(n.Rparen, len(")")))
+		}
+
+	case *ast.GoStmt:
+		children = append(children,
+			tok(n.Go, len("go")))
+
+	case *ast.Ident:
+		children = append(children,
+			tok(n.NamePos, len(n.Name)))
+
+	case *ast.IfStmt:
+		children = append(children,
+			tok(n.If, len("if")))
+
+	case *ast.ImportSpec:
+		// TODO(adonovan): ImportSpec.{Doc,EndPos}?
+
+	case *ast.IncDecStmt:
+		children = append(children,
+			tok(n.TokPos, len(n.Tok.String())))
+
+	case *ast.IndexExpr:
+		children = append(children,
+			tok(n.Lbrack, len("[")),
+			tok(n.Rbrack, len("]")))
+
+	case *ast.IndexListExpr:
+		children = append(children,
+			tok(n.Lbrack, len("[")),
+			tok(n.Rbrack, len("]")))
+
+	case *ast.InterfaceType:
+		children = append(children,
+			tok(n.Interface, len("interface")))
+
+	case *ast.KeyValueExpr:
+		children = append(children,
+			tok(n.Colon, len(":")))
+
+	case *ast.LabeledStmt:
+		children = append(children,
+			tok(n.Colon, len(":")))
+
+	case *ast.MapType:
+		children = append(children,
+			tok(n.Map, len("map")))
+
+	case *ast.ParenExpr:
+		children = append(children,
+			tok(n.Lparen, len("(")),
+			tok(n.Rparen, len(")")))
+
+	case *ast.RangeStmt:
+		children = append(children,
+			tok(n.For, len("for")),
+			tok(n.TokPos, len(n.Tok.String())))
+
+	case *ast.ReturnStmt:
+		children = append(children,
+			tok(n.Return, len("return")))
+
+	case *ast.SelectStmt:
+		children = append(children,
+			tok(n.Select, len("select")))
+
+	case *ast.SelectorExpr:
+		// nop
+
+	case *ast.SendStmt:
+		children = append(children,
+			tok(n.Arrow, len("<-")))
+
+	case *ast.SliceExpr:
+		children = append(children,
+			tok(n.Lbrack, len("[")),
+			tok(n.Rbrack, len("]")))
+
+	case *ast.StarExpr:
+		children = append(children, tok(n.Star, len("*")))
+
+	case *ast.StructType:
+		children = append(children, tok(n.Struct, len("struct")))
+
+	case *ast.SwitchStmt:
+		children = append(children, tok(n.Switch, len("switch")))
+
+	case *ast.TypeAssertExpr:
+		children = append(children,
+			tok(n.Lparen-1, len(".")),
+			tok(n.Lparen, len("(")),
+			tok(n.Rparen, len(")")))
+
+	case *ast.TypeSpec:
+		// TODO(adonovan): TypeSpec.{Doc,Comment}?
+
+	case *ast.TypeSwitchStmt:
+		children = append(children, tok(n.Switch, len("switch")))
+
+	case *ast.UnaryExpr:
+		children = append(children, tok(n.OpPos, len(n.Op.String())))
+
+	case *ast.ValueSpec:
+		// TODO(adonovan): ValueSpec.{Doc,Comment}?
+
+	case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt:
+		// nop
+	}
+
+	// TODO(adonovan): opt: merge the logic of ast.Inspect() into
+	// the switch above so we can make interleaved callbacks for
+	// both Nodes and Tokens in the right order and avoid the need
+	// to sort.
+	sort.Sort(byPos(children))
+
+	return children
+}
+
+type byPos []ast.Node
+
+func (sl byPos) Len() int {
+	return len(sl)
+}
+func (sl byPos) Less(i, j int) bool {
+	return sl[i].Pos() < sl[j].Pos()
+}
+func (sl byPos) Swap(i, j int) {
+	sl[i], sl[j] = sl[j], sl[i]
+}
+
+// NodeDescription returns a description of the concrete type of n suitable
+// for a user interface.
+//
+// TODO(adonovan): in some cases (e.g. Field, FieldList, Ident,
+// StarExpr) we could be much more specific given the path to the AST
+// root.  Perhaps we should do that.
+func NodeDescription(n ast.Node) string {
+	switch n := n.(type) {
+	case *ast.ArrayType:
+		return "array type"
+	case *ast.AssignStmt:
+		return "assignment"
+	case *ast.BadDecl:
+		return "bad declaration"
+	case *ast.BadExpr:
+		return "bad expression"
+	case *ast.BadStmt:
+		return "bad statement"
+	case *ast.BasicLit:
+		return "basic literal"
+	case *ast.BinaryExpr:
+		return fmt.Sprintf("binary %s operation", n.Op)
+	case *ast.BlockStmt:
+		return "block"
+	case *ast.BranchStmt:
+		switch n.Tok {
+		case token.BREAK:
+			return "break statement"
+		case token.CONTINUE:
+			return "continue statement"
+		case token.GOTO:
+			return "goto statement"
+		case token.FALLTHROUGH:
+			return "fall-through statement"
+		}
+	case *ast.CallExpr:
+		if len(n.Args) == 1 && !n.Ellipsis.IsValid() {
+			return "function call (or conversion)"
+		}
+		return "function call"
+	case *ast.CaseClause:
+		return "case clause"
+	case *ast.ChanType:
+		return "channel type"
+	case *ast.CommClause:
+		return "communication clause"
+	case *ast.Comment:
+		return "comment"
+	case *ast.CommentGroup:
+		return "comment group"
+	case *ast.CompositeLit:
+		return "composite literal"
+	case *ast.DeclStmt:
+		return NodeDescription(n.Decl) + " statement"
+	case *ast.DeferStmt:
+		return "defer statement"
+	case *ast.Ellipsis:
+		return "ellipsis"
+	case *ast.EmptyStmt:
+		return "empty statement"
+	case *ast.ExprStmt:
+		return "expression statement"
+	case *ast.Field:
+		// Can be any of these:
+		// struct {x, y int}  -- struct field(s)
+		// struct {T}         -- anon struct field
+		// interface {I}      -- interface embedding
+		// interface {f()}    -- interface method
+		// func (A) func(B) C -- receiver, param(s), result(s)
+		return "field/method/parameter"
+	case *ast.FieldList:
+		return "field/method/parameter list"
+	case *ast.File:
+		return "source file"
+	case *ast.ForStmt:
+		return "for loop"
+	case *ast.FuncDecl:
+		return "function declaration"
+	case *ast.FuncLit:
+		return "function literal"
+	case *ast.FuncType:
+		return "function type"
+	case *ast.GenDecl:
+		switch n.Tok {
+		case token.IMPORT:
+			return "import declaration"
+		case token.CONST:
+			return "constant declaration"
+		case token.TYPE:
+			return "type declaration"
+		case token.VAR:
+			return "variable declaration"
+		}
+	case *ast.GoStmt:
+		return "go statement"
+	case *ast.Ident:
+		return "identifier"
+	case *ast.IfStmt:
+		return "if statement"
+	case *ast.ImportSpec:
+		return "import specification"
+	case *ast.IncDecStmt:
+		if n.Tok == token.INC {
+			return "increment statement"
+		}
+		return "decrement statement"
+	case *ast.IndexExpr:
+		return "index expression"
+	case *ast.IndexListExpr:
+		return "index list expression"
+	case *ast.InterfaceType:
+		return "interface type"
+	case *ast.KeyValueExpr:
+		return "key/value association"
+	case *ast.LabeledStmt:
+		return "statement label"
+	case *ast.MapType:
+		return "map type"
+	case *ast.Package:
+		return "package"
+	case *ast.ParenExpr:
+		return "parenthesized " + NodeDescription(n.X)
+	case *ast.RangeStmt:
+		return "range loop"
+	case *ast.ReturnStmt:
+		return "return statement"
+	case *ast.SelectStmt:
+		return "select statement"
+	case *ast.SelectorExpr:
+		return "selector"
+	case *ast.SendStmt:
+		return "channel send"
+	case *ast.SliceExpr:
+		return "slice expression"
+	case *ast.StarExpr:
+		return "*-operation" // load/store expr or pointer type
+	case *ast.StructType:
+		return "struct type"
+	case *ast.SwitchStmt:
+		return "switch statement"
+	case *ast.TypeAssertExpr:
+		return "type assertion"
+	case *ast.TypeSpec:
+		return "type specification"
+	case *ast.TypeSwitchStmt:
+		return "type switch"
+	case *ast.UnaryExpr:
+		return fmt.Sprintf("unary %s operation", n.Op)
+	case *ast.ValueSpec:
+		return "value specification"
+
+	}
+	panic(fmt.Sprintf("unexpected node type: %T", n))
+}
+
+func is[T any](x any) bool {
+	_, ok := x.(T)
+	return ok
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/imports.go b/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/imports.go
new file mode 100644
index 00000000000000..5bacc0fa49e031
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/imports.go
@@ -0,0 +1,472 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package astutil contains common utilities for working with the Go AST.
+package astutil // import "golang.org/x/tools/go/ast/astutil"
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"slices"
+	"strconv"
+	"strings"
+)
+
+// AddImport adds the import path to the file f, if absent.
+func AddImport(fset *token.FileSet, f *ast.File, path string) (added bool) {
+	return AddNamedImport(fset, f, "", path)
+}
+
+// AddNamedImport adds the import with the given name and path to the file f, if absent.
+// If name is not empty, it is used to rename the import.
+//
+// For example, calling
+//
+//	AddNamedImport(fset, f, "pathpkg", "path")
+//
+// adds
+//
+//	import pathpkg "path"
+func AddNamedImport(fset *token.FileSet, f *ast.File, name, path string) (added bool) {
+	if imports(f, name, path) {
+		return false
+	}
+
+	newImport := &ast.ImportSpec{
+		Path: &ast.BasicLit{
+			Kind:  token.STRING,
+			Value: strconv.Quote(path),
+		},
+	}
+	if name != "" {
+		newImport.Name = &ast.Ident{Name: name}
+	}
+
+	// Find an import decl to add to.
+	// The goal is to find an existing import
+	// whose import path has the longest shared
+	// prefix with path.
+	var (
+		bestMatch  = -1         // length of longest shared prefix
+		lastImport = -1         // index in f.Decls of the file's final import decl
+		impDecl    *ast.GenDecl // import decl containing the best match
+		impIndex   = -1         // spec index in impDecl containing the best match
+
+		isThirdPartyPath = isThirdParty(path)
+	)
+	for i, decl := range f.Decls {
+		gen, ok := decl.(*ast.GenDecl)
+		if ok && gen.Tok == token.IMPORT {
+			lastImport = i
+			// Do not add to import "C", to avoid disrupting the
+			// association with its doc comment, breaking cgo.
+			if declImports(gen, "C") {
+				continue
+			}
+
+			// Match an empty import decl if that's all that is available.
+			if len(gen.Specs) == 0 && bestMatch == -1 {
+				impDecl = gen
+			}
+
+			// Compute longest shared prefix with imports in this group and find best
+			// matched import spec.
+			// 1. Always prefer import spec with longest shared prefix.
+			// 2. While match length is 0,
+			// - for stdlib package: prefer first import spec.
+			// - for third party package: prefer first third party import spec.
+			// We cannot use last import spec as best match for third party package
+			// because grouped imports are usually placed last by goimports -local
+			// flag.
+			// See issue #19190.
+			seenAnyThirdParty := false
+			for j, spec := range gen.Specs {
+				impspec := spec.(*ast.ImportSpec)
+				p := importPath(impspec)
+				n := matchLen(p, path)
+				if n > bestMatch || (bestMatch == 0 && !seenAnyThirdParty && isThirdPartyPath) {
+					bestMatch = n
+					impDecl = gen
+					impIndex = j
+				}
+				seenAnyThirdParty = seenAnyThirdParty || isThirdParty(p)
+			}
+		}
+	}
+
+	// If no import decl found, add one after the last import.
+	if impDecl == nil {
+		impDecl = &ast.GenDecl{
+			Tok: token.IMPORT,
+		}
+		if lastImport >= 0 {
+			impDecl.TokPos = f.Decls[lastImport].End()
+		} else {
+			// There are no existing imports.
+			// Our new import, preceded by a blank line,  goes after the package declaration
+			// and after the comment, if any, that starts on the same line as the
+			// package declaration.
+			impDecl.TokPos = f.Package
+
+			file := fset.File(f.Package)
+			pkgLine := file.Line(f.Package)
+			for _, c := range f.Comments {
+				if file.Line(c.Pos()) > pkgLine {
+					break
+				}
+				// +2 for a blank line
+				impDecl.TokPos = c.End() + 2
+			}
+		}
+		f.Decls = append(f.Decls, nil)
+		copy(f.Decls[lastImport+2:], f.Decls[lastImport+1:])
+		f.Decls[lastImport+1] = impDecl
+	}
+
+	// Insert new import at insertAt.
+	insertAt := 0
+	if impIndex >= 0 {
+		// insert after the found import
+		insertAt = impIndex + 1
+	}
+	impDecl.Specs = append(impDecl.Specs, nil)
+	copy(impDecl.Specs[insertAt+1:], impDecl.Specs[insertAt:])
+	impDecl.Specs[insertAt] = newImport
+	pos := impDecl.Pos()
+	if insertAt > 0 {
+		// If there is a comment after an existing import, preserve the comment
+		// position by adding the new import after the comment.
+		if spec, ok := impDecl.Specs[insertAt-1].(*ast.ImportSpec); ok && spec.Comment != nil {
+			pos = spec.Comment.End()
+		} else {
+			// Assign same position as the previous import,
+			// so that the sorter sees it as being in the same block.
+			pos = impDecl.Specs[insertAt-1].Pos()
+		}
+	}
+	if newImport.Name != nil {
+		newImport.Name.NamePos = pos
+	}
+	newImport.Path.ValuePos = pos
+	newImport.EndPos = pos
+
+	// Clean up parens. impDecl contains at least one spec.
+	if len(impDecl.Specs) == 1 {
+		// Remove unneeded parens.
+		impDecl.Lparen = token.NoPos
+	} else if !impDecl.Lparen.IsValid() {
+		// impDecl needs parens added.
+		impDecl.Lparen = impDecl.Specs[0].Pos()
+	}
+
+	f.Imports = append(f.Imports, newImport)
+
+	if len(f.Decls) <= 1 {
+		return true
+	}
+
+	// Merge all the import declarations into the first one.
+	var first *ast.GenDecl
+	for i := 0; i < len(f.Decls); i++ {
+		decl := f.Decls[i]
+		gen, ok := decl.(*ast.GenDecl)
+		if !ok || gen.Tok != token.IMPORT || declImports(gen, "C") {
+			continue
+		}
+		if first == nil {
+			first = gen
+			continue // Don't touch the first one.
+		}
+		// We now know there is more than one package in this import
+		// declaration. Ensure that it ends up parenthesized.
+		first.Lparen = first.Pos()
+		// Move the imports of the other import declaration to the first one.
+		for _, spec := range gen.Specs {
+			spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()
+			first.Specs = append(first.Specs, spec)
+		}
+		f.Decls = slices.Delete(f.Decls, i, i+1)
+		i--
+	}
+
+	return true
+}
+
+func isThirdParty(importPath string) bool {
+	// Third party package import path usually contains "." (".com", ".org", ...)
+	// This logic is taken from golang.org/x/tools/imports package.
+	return strings.Contains(importPath, ".")
+}
+
+// DeleteImport deletes the import path from the file f, if present.
+// If there are duplicate import declarations, all matching ones are deleted.
+func DeleteImport(fset *token.FileSet, f *ast.File, path string) (deleted bool) {
+	return DeleteNamedImport(fset, f, "", path)
+}
+
+// DeleteNamedImport deletes the import with the given name and path from the file f, if present.
+// If there are duplicate import declarations, all matching ones are deleted.
+func DeleteNamedImport(fset *token.FileSet, f *ast.File, name, path string) (deleted bool) {
+	var (
+		delspecs    = make(map[*ast.ImportSpec]bool)
+		delcomments = make(map[*ast.CommentGroup]bool)
+	)
+
+	// Find the import nodes that import path, if any.
+	for i := 0; i < len(f.Decls); i++ {
+		gen, ok := f.Decls[i].(*ast.GenDecl)
+		if !ok || gen.Tok != token.IMPORT {
+			continue
+		}
+		for j := 0; j < len(gen.Specs); j++ {
+			impspec := gen.Specs[j].(*ast.ImportSpec)
+			if importName(impspec) != name || importPath(impspec) != path {
+				continue
+			}
+
+			// We found an import spec that imports path.
+			// Delete it.
+			delspecs[impspec] = true
+			deleted = true
+			gen.Specs = slices.Delete(gen.Specs, j, j+1)
+
+			// If this was the last import spec in this decl,
+			// delete the decl, too.
+			if len(gen.Specs) == 0 {
+				f.Decls = slices.Delete(f.Decls, i, i+1)
+				i--
+				break
+			} else if len(gen.Specs) == 1 {
+				if impspec.Doc != nil {
+					delcomments[impspec.Doc] = true
+				}
+				if impspec.Comment != nil {
+					delcomments[impspec.Comment] = true
+				}
+				for _, cg := range f.Comments {
+					// Found comment on the same line as the import spec.
+					if cg.End() < impspec.Pos() && fset.Position(cg.End()).Line == fset.Position(impspec.Pos()).Line {
+						delcomments[cg] = true
+						break
+					}
+				}
+
+				spec := gen.Specs[0].(*ast.ImportSpec)
+
+				// Move the documentation right after the import decl.
+				if spec.Doc != nil {
+					for fset.Position(gen.TokPos).Line+1 < fset.Position(spec.Doc.Pos()).Line {
+						fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
+					}
+				}
+				for _, cg := range f.Comments {
+					if cg.End() < spec.Pos() && fset.Position(cg.End()).Line == fset.Position(spec.Pos()).Line {
+						for fset.Position(gen.TokPos).Line+1 < fset.Position(spec.Pos()).Line {
+							fset.File(gen.TokPos).MergeLine(fset.Position(gen.TokPos).Line)
+						}
+						break
+					}
+				}
+			}
+			if j > 0 {
+				lastImpspec := gen.Specs[j-1].(*ast.ImportSpec)
+				lastLine := fset.PositionFor(lastImpspec.Path.ValuePos, false).Line
+				line := fset.PositionFor(impspec.Path.ValuePos, false).Line
+
+				// We deleted an entry but now there may be
+				// a blank line-sized hole where the import was.
+				if line-lastLine > 1 || !gen.Rparen.IsValid() {
+					// There was a blank line immediately preceding the deleted import,
+					// so there's no need to close the hole. The right parenthesis is
+					// invalid after AddImport to an import statement without parenthesis.
+					// Do nothing.
+				} else if line != fset.File(gen.Rparen).LineCount() {
+					// There was no blank line. Close the hole.
+					fset.File(gen.Rparen).MergeLine(line)
+				}
+			}
+			j--
+		}
+	}
+
+	// Delete imports from f.Imports.
+	before := len(f.Imports)
+	f.Imports = slices.DeleteFunc(f.Imports, func(imp *ast.ImportSpec) bool {
+		_, ok := delspecs[imp]
+		return ok
+	})
+	if len(f.Imports)+len(delspecs) != before {
+		// This can happen when the AST is invalid (i.e. imports differ between f.Decls and f.Imports).
+		panic(fmt.Sprintf("deleted specs from Decls but not Imports: %v", delspecs))
+	}
+
+	// Delete comments from f.Comments.
+	f.Comments = slices.DeleteFunc(f.Comments, func(cg *ast.CommentGroup) bool {
+		_, ok := delcomments[cg]
+		return ok
+	})
+
+	return
+}
+
+// RewriteImport rewrites any import of path oldPath to path newPath.
+func RewriteImport(fset *token.FileSet, f *ast.File, oldPath, newPath string) (rewrote bool) {
+	for _, imp := range f.Imports {
+		if importPath(imp) == oldPath {
+			rewrote = true
+			// record old End, because the default is to compute
+			// it using the length of imp.Path.Value.
+			imp.EndPos = imp.End()
+			imp.Path.Value = strconv.Quote(newPath)
+		}
+	}
+	return
+}
+
+// UsesImport reports whether a given import is used.
+// The provided File must have been parsed with syntactic object resolution
+// (not using go/parser.SkipObjectResolution).
+func UsesImport(f *ast.File, path string) (used bool) {
+	if f.Scope == nil {
+		panic("file f was not parsed with syntactic object resolution")
+	}
+	spec := importSpec(f, path)
+	if spec == nil {
+		return
+	}
+
+	name := spec.Name.String()
+	switch name {
+	case "":
+		// If the package name is not explicitly specified,
+		// make an educated guess. This is not guaranteed to be correct.
+		lastSlash := strings.LastIndex(path, "/")
+		if lastSlash == -1 {
+			name = path
+		} else {
+			name = path[lastSlash+1:]
+		}
+	case "_", ".":
+		// Not sure if this import is used - err on the side of caution.
+		return true
+	}
+
+	ast.Walk(visitFn(func(n ast.Node) {
+		sel, ok := n.(*ast.SelectorExpr)
+		if ok && isTopName(sel.X, name) {
+			used = true
+		}
+	}), f)
+
+	return
+}
+
+type visitFn func(node ast.Node)
+
+func (fn visitFn) Visit(node ast.Node) ast.Visitor {
+	fn(node)
+	return fn
+}
+
+// imports reports whether f has an import with the specified name and path.
+func imports(f *ast.File, name, path string) bool {
+	for _, s := range f.Imports {
+		if importName(s) == name && importPath(s) == path {
+			return true
+		}
+	}
+	return false
+}
+
+// importSpec returns the import spec if f imports path,
+// or nil otherwise.
+func importSpec(f *ast.File, path string) *ast.ImportSpec {
+	for _, s := range f.Imports {
+		if importPath(s) == path {
+			return s
+		}
+	}
+	return nil
+}
+
+// importName returns the name of s,
+// or "" if the import is not named.
+func importName(s *ast.ImportSpec) string {
+	if s.Name == nil {
+		return ""
+	}
+	return s.Name.Name
+}
+
+// importPath returns the unquoted import path of s,
+// or "" if the path is not properly quoted.
+func importPath(s *ast.ImportSpec) string {
+	t, err := strconv.Unquote(s.Path.Value)
+	if err != nil {
+		return ""
+	}
+	return t
+}
+
+// declImports reports whether gen contains an import of path.
+func declImports(gen *ast.GenDecl, path string) bool {
+	if gen.Tok != token.IMPORT {
+		return false
+	}
+	for _, spec := range gen.Specs {
+		impspec := spec.(*ast.ImportSpec)
+		if importPath(impspec) == path {
+			return true
+		}
+	}
+	return false
+}
+
+// matchLen returns the length of the longest path segment prefix shared by x and y.
+func matchLen(x, y string) int {
+	n := 0
+	for i := 0; i < len(x) && i < len(y) && x[i] == y[i]; i++ {
+		if x[i] == '/' {
+			n++
+		}
+	}
+	return n
+}
+
+// isTopName returns true if n is a top-level unresolved identifier with the given name.
+func isTopName(n ast.Expr, name string) bool {
+	id, ok := n.(*ast.Ident)
+	return ok && id.Name == name && id.Obj == nil
+}
+
+// Imports returns the file imports grouped by paragraph.
+func Imports(fset *token.FileSet, f *ast.File) [][]*ast.ImportSpec {
+	var groups [][]*ast.ImportSpec
+
+	for _, decl := range f.Decls {
+		genDecl, ok := decl.(*ast.GenDecl)
+		if !ok || genDecl.Tok != token.IMPORT {
+			break
+		}
+
+		group := []*ast.ImportSpec{}
+
+		var lastLine int
+		for _, spec := range genDecl.Specs {
+			importSpec := spec.(*ast.ImportSpec)
+			pos := importSpec.Path.ValuePos
+			line := fset.Position(pos).Line
+			if lastLine > 0 && pos > 0 && line-lastLine > 1 {
+				groups = append(groups, group)
+				group = []*ast.ImportSpec{}
+			}
+			group = append(group, importSpec)
+			lastLine = line
+		}
+		groups = append(groups, group)
+	}
+
+	return groups
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/rewrite.go b/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/rewrite.go
new file mode 100644
index 00000000000000..4ad0549304ca21
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/rewrite.go
@@ -0,0 +1,490 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package astutil
+
+import (
+	"fmt"
+	"go/ast"
+	"reflect"
+	"sort"
+)
+
+// An ApplyFunc is invoked by Apply for each node n, even if n is nil,
+// before and/or after the node's children, using a Cursor describing
+// the current node and providing operations on it.
+//
+// The return value of ApplyFunc controls the syntax tree traversal.
+// See Apply for details.
+type ApplyFunc func(*Cursor) bool
+
+// Apply traverses a syntax tree recursively, starting with root,
+// and calling pre and post for each node as described below.
+// Apply returns the syntax tree, possibly modified.
+//
+// If pre is not nil, it is called for each node before the node's
+// children are traversed (pre-order). If pre returns false, no
+// children are traversed, and post is not called for that node.
+//
+// If post is not nil, and a prior call of pre didn't return false,
+// post is called for each node after its children are traversed
+// (post-order). If post returns false, traversal is terminated and
+// Apply returns immediately.
+//
+// Only fields that refer to AST nodes are considered children;
+// i.e., token.Pos, Scopes, Objects, and fields of basic types
+// (strings, etc.) are ignored.
+//
+// Children are traversed in the order in which they appear in the
+// respective node's struct definition. A package's files are
+// traversed in the filenames' alphabetical order.
+func Apply(root ast.Node, pre, post ApplyFunc) (result ast.Node) {
+	parent := &struct{ ast.Node }{root}
+	defer func() {
+		if r := recover(); r != nil && r != abort {
+			panic(r)
+		}
+		result = parent.Node
+	}()
+	a := &application{pre: pre, post: post}
+	a.apply(parent, "Node", nil, root)
+	return
+}
+
+var abort = new(int) // singleton, to signal termination of Apply
+
+// A Cursor describes a node encountered during Apply.
+// Information about the node and its parent is available
+// from the Node, Parent, Name, and Index methods.
+//
+// If p is a variable of type and value of the current parent node
+// c.Parent(), and f is the field identifier with name c.Name(),
+// the following invariants hold:
+//
+//	p.f            == c.Node()  if c.Index() <  0
+//	p.f[c.Index()] == c.Node()  if c.Index() >= 0
+//
+// The methods Replace, Delete, InsertBefore, and InsertAfter
+// can be used to change the AST without disrupting Apply.
+//
+// This type is not to be confused with [inspector.Cursor] from
+// package [golang.org/x/tools/go/ast/inspector], which provides
+// stateless navigation of immutable syntax trees.
+type Cursor struct {
+	parent ast.Node
+	name   string
+	iter   *iterator // valid if non-nil
+	node   ast.Node
+}
+
+// Node returns the current Node.
+func (c *Cursor) Node() ast.Node { return c.node }
+
+// Parent returns the parent of the current Node.
+func (c *Cursor) Parent() ast.Node { return c.parent }
+
+// Name returns the name of the parent Node field that contains the current Node.
+// If the parent is a *ast.Package and the current Node is a *ast.File, Name returns
+// the filename for the current Node.
+func (c *Cursor) Name() string { return c.name }
+
+// Index reports the index >= 0 of the current Node in the slice of Nodes that
+// contains it, or a value < 0 if the current Node is not part of a slice.
+// The index of the current node changes if InsertBefore is called while
+// processing the current node.
+func (c *Cursor) Index() int {
+	if c.iter != nil {
+		return c.iter.index
+	}
+	return -1
+}
+
+// field returns the current node's parent field value.
+func (c *Cursor) field() reflect.Value {
+	return reflect.Indirect(reflect.ValueOf(c.parent)).FieldByName(c.name)
+}
+
+// Replace replaces the current Node with n.
+// The replacement node is not walked by Apply.
+func (c *Cursor) Replace(n ast.Node) {
+	if _, ok := c.node.(*ast.File); ok {
+		file, ok := n.(*ast.File)
+		if !ok {
+			panic("attempt to replace *ast.File with non-*ast.File")
+		}
+		c.parent.(*ast.Package).Files[c.name] = file
+		return
+	}
+
+	v := c.field()
+	if i := c.Index(); i >= 0 {
+		v = v.Index(i)
+	}
+	v.Set(reflect.ValueOf(n))
+}
+
+// Delete deletes the current Node from its containing slice.
+// If the current Node is not part of a slice, Delete panics.
+// As a special case, if the current node is a package file,
+// Delete removes it from the package's Files map.
+func (c *Cursor) Delete() {
+	if _, ok := c.node.(*ast.File); ok {
+		delete(c.parent.(*ast.Package).Files, c.name)
+		return
+	}
+
+	i := c.Index()
+	if i < 0 {
+		panic("Delete node not contained in slice")
+	}
+	v := c.field()
+	l := v.Len()
+	reflect.Copy(v.Slice(i, l), v.Slice(i+1, l))
+	v.Index(l - 1).Set(reflect.Zero(v.Type().Elem()))
+	v.SetLen(l - 1)
+	c.iter.step--
+}
+
+// InsertAfter inserts n after the current Node in its containing slice.
+// If the current Node is not part of a slice, InsertAfter panics.
+// Apply does not walk n.
+func (c *Cursor) InsertAfter(n ast.Node) {
+	i := c.Index()
+	if i < 0 {
+		panic("InsertAfter node not contained in slice")
+	}
+	v := c.field()
+	v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
+	l := v.Len()
+	reflect.Copy(v.Slice(i+2, l), v.Slice(i+1, l))
+	v.Index(i + 1).Set(reflect.ValueOf(n))
+	c.iter.step++
+}
+
+// InsertBefore inserts n before the current Node in its containing slice.
+// If the current Node is not part of a slice, InsertBefore panics.
+// Apply will not walk n.
+func (c *Cursor) InsertBefore(n ast.Node) {
+	i := c.Index()
+	if i < 0 {
+		panic("InsertBefore node not contained in slice")
+	}
+	v := c.field()
+	v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
+	l := v.Len()
+	reflect.Copy(v.Slice(i+1, l), v.Slice(i, l))
+	v.Index(i).Set(reflect.ValueOf(n))
+	c.iter.index++
+}
+
+// application carries all the shared data so we can pass it around cheaply.
+type application struct {
+	pre, post ApplyFunc
+	cursor    Cursor
+	iter      iterator
+}
+
+func (a *application) apply(parent ast.Node, name string, iter *iterator, n ast.Node) {
+	// convert typed nil into untyped nil
+	if v := reflect.ValueOf(n); v.Kind() == reflect.Pointer && v.IsNil() {
+		n = nil
+	}
+
+	// avoid heap-allocating a new cursor for each apply call; reuse a.cursor instead
+	saved := a.cursor
+	a.cursor.parent = parent
+	a.cursor.name = name
+	a.cursor.iter = iter
+	a.cursor.node = n
+
+	if a.pre != nil && !a.pre(&a.cursor) {
+		a.cursor = saved
+		return
+	}
+
+	// walk children
+	// (the order of the cases matches the order of the corresponding node types in go/ast)
+	switch n := n.(type) {
+	case nil:
+		// nothing to do
+
+	// Comments and fields
+	case *ast.Comment:
+		// nothing to do
+
+	case *ast.CommentGroup:
+		if n != nil {
+			a.applyList(n, "List")
+		}
+
+	case *ast.Field:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.applyList(n, "Names")
+		a.apply(n, "Type", nil, n.Type)
+		a.apply(n, "Tag", nil, n.Tag)
+		a.apply(n, "Comment", nil, n.Comment)
+
+	case *ast.FieldList:
+		a.applyList(n, "List")
+
+	// Expressions
+	case *ast.BadExpr, *ast.Ident, *ast.BasicLit:
+		// nothing to do
+
+	case *ast.Ellipsis:
+		a.apply(n, "Elt", nil, n.Elt)
+
+	case *ast.FuncLit:
+		a.apply(n, "Type", nil, n.Type)
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.CompositeLit:
+		a.apply(n, "Type", nil, n.Type)
+		a.applyList(n, "Elts")
+
+	case *ast.ParenExpr:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.SelectorExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Sel", nil, n.Sel)
+
+	case *ast.IndexExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Index", nil, n.Index)
+
+	case *ast.IndexListExpr:
+		a.apply(n, "X", nil, n.X)
+		a.applyList(n, "Indices")
+
+	case *ast.SliceExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Low", nil, n.Low)
+		a.apply(n, "High", nil, n.High)
+		a.apply(n, "Max", nil, n.Max)
+
+	case *ast.TypeAssertExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Type", nil, n.Type)
+
+	case *ast.CallExpr:
+		a.apply(n, "Fun", nil, n.Fun)
+		a.applyList(n, "Args")
+
+	case *ast.StarExpr:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.UnaryExpr:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.BinaryExpr:
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Y", nil, n.Y)
+
+	case *ast.KeyValueExpr:
+		a.apply(n, "Key", nil, n.Key)
+		a.apply(n, "Value", nil, n.Value)
+
+	// Types
+	case *ast.ArrayType:
+		a.apply(n, "Len", nil, n.Len)
+		a.apply(n, "Elt", nil, n.Elt)
+
+	case *ast.StructType:
+		a.apply(n, "Fields", nil, n.Fields)
+
+	case *ast.FuncType:
+		if tparams := n.TypeParams; tparams != nil {
+			a.apply(n, "TypeParams", nil, tparams)
+		}
+		a.apply(n, "Params", nil, n.Params)
+		a.apply(n, "Results", nil, n.Results)
+
+	case *ast.InterfaceType:
+		a.apply(n, "Methods", nil, n.Methods)
+
+	case *ast.MapType:
+		a.apply(n, "Key", nil, n.Key)
+		a.apply(n, "Value", nil, n.Value)
+
+	case *ast.ChanType:
+		a.apply(n, "Value", nil, n.Value)
+
+	// Statements
+	case *ast.BadStmt:
+		// nothing to do
+
+	case *ast.DeclStmt:
+		a.apply(n, "Decl", nil, n.Decl)
+
+	case *ast.EmptyStmt:
+		// nothing to do
+
+	case *ast.LabeledStmt:
+		a.apply(n, "Label", nil, n.Label)
+		a.apply(n, "Stmt", nil, n.Stmt)
+
+	case *ast.ExprStmt:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.SendStmt:
+		a.apply(n, "Chan", nil, n.Chan)
+		a.apply(n, "Value", nil, n.Value)
+
+	case *ast.IncDecStmt:
+		a.apply(n, "X", nil, n.X)
+
+	case *ast.AssignStmt:
+		a.applyList(n, "Lhs")
+		a.applyList(n, "Rhs")
+
+	case *ast.GoStmt:
+		a.apply(n, "Call", nil, n.Call)
+
+	case *ast.DeferStmt:
+		a.apply(n, "Call", nil, n.Call)
+
+	case *ast.ReturnStmt:
+		a.applyList(n, "Results")
+
+	case *ast.BranchStmt:
+		a.apply(n, "Label", nil, n.Label)
+
+	case *ast.BlockStmt:
+		a.applyList(n, "List")
+
+	case *ast.IfStmt:
+		a.apply(n, "Init", nil, n.Init)
+		a.apply(n, "Cond", nil, n.Cond)
+		a.apply(n, "Body", nil, n.Body)
+		a.apply(n, "Else", nil, n.Else)
+
+	case *ast.CaseClause:
+		a.applyList(n, "List")
+		a.applyList(n, "Body")
+
+	case *ast.SwitchStmt:
+		a.apply(n, "Init", nil, n.Init)
+		a.apply(n, "Tag", nil, n.Tag)
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.TypeSwitchStmt:
+		a.apply(n, "Init", nil, n.Init)
+		a.apply(n, "Assign", nil, n.Assign)
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.CommClause:
+		a.apply(n, "Comm", nil, n.Comm)
+		a.applyList(n, "Body")
+
+	case *ast.SelectStmt:
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.ForStmt:
+		a.apply(n, "Init", nil, n.Init)
+		a.apply(n, "Cond", nil, n.Cond)
+		a.apply(n, "Post", nil, n.Post)
+		a.apply(n, "Body", nil, n.Body)
+
+	case *ast.RangeStmt:
+		a.apply(n, "Key", nil, n.Key)
+		a.apply(n, "Value", nil, n.Value)
+		a.apply(n, "X", nil, n.X)
+		a.apply(n, "Body", nil, n.Body)
+
+	// Declarations
+	case *ast.ImportSpec:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.apply(n, "Name", nil, n.Name)
+		a.apply(n, "Path", nil, n.Path)
+		a.apply(n, "Comment", nil, n.Comment)
+
+	case *ast.ValueSpec:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.applyList(n, "Names")
+		a.apply(n, "Type", nil, n.Type)
+		a.applyList(n, "Values")
+		a.apply(n, "Comment", nil, n.Comment)
+
+	case *ast.TypeSpec:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.apply(n, "Name", nil, n.Name)
+		if tparams := n.TypeParams; tparams != nil {
+			a.apply(n, "TypeParams", nil, tparams)
+		}
+		a.apply(n, "Type", nil, n.Type)
+		a.apply(n, "Comment", nil, n.Comment)
+
+	case *ast.BadDecl:
+		// nothing to do
+
+	case *ast.GenDecl:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.applyList(n, "Specs")
+
+	case *ast.FuncDecl:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.apply(n, "Recv", nil, n.Recv)
+		a.apply(n, "Name", nil, n.Name)
+		a.apply(n, "Type", nil, n.Type)
+		a.apply(n, "Body", nil, n.Body)
+
+	// Files and packages
+	case *ast.File:
+		a.apply(n, "Doc", nil, n.Doc)
+		a.apply(n, "Name", nil, n.Name)
+		a.applyList(n, "Decls")
+		// Don't walk n.Comments; they have either been walked already if
+		// they are Doc comments, or they can be easily walked explicitly.
+
+	case *ast.Package:
+		// collect and sort names for reproducible behavior
+		var names []string
+		for name := range n.Files {
+			names = append(names, name)
+		}
+		sort.Strings(names)
+		for _, name := range names {
+			a.apply(n, name, nil, n.Files[name])
+		}
+
+	default:
+		panic(fmt.Sprintf("Apply: unexpected node type %T", n))
+	}
+
+	if a.post != nil && !a.post(&a.cursor) {
+		panic(abort)
+	}
+
+	a.cursor = saved
+}
+
+// An iterator controls iteration over a slice of nodes.
+type iterator struct {
+	index, step int
+}
+
+func (a *application) applyList(parent ast.Node, name string) {
+	// avoid heap-allocating a new iterator for each applyList call; reuse a.iter instead
+	saved := a.iter
+	a.iter.index = 0
+	for {
+		// must reload parent.name each time, since cursor modifications might change it
+		v := reflect.Indirect(reflect.ValueOf(parent)).FieldByName(name)
+		if a.iter.index >= v.Len() {
+			break
+		}
+
+		// element x may be nil in a bad AST - be cautious
+		var x ast.Node
+		if e := v.Index(a.iter.index); e.IsValid() {
+			x = e.Interface().(ast.Node)
+		}
+
+		a.iter.step = 1
+		a.apply(parent, name, &a.iter, x)
+		a.iter.index += a.iter.step
+	}
+	a.iter = saved
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/util.go b/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/util.go
new file mode 100644
index 00000000000000..c820b20849953a
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/ast/astutil/util.go
@@ -0,0 +1,13 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package astutil
+
+import "go/ast"
+
+// Unparen returns e with any enclosing parentheses stripped.
+// Deprecated: use [ast.Unparen].
+//
+//go:fix inline
+func Unparen(e ast.Expr) ast.Expr { return ast.Unparen(e) }
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/generated/generated.go b/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/generated/generated.go
new file mode 100644
index 00000000000000..13e1b69021ac71
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/analysisinternal/generated/generated.go
@@ -0,0 +1,41 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package generated defines an analyzer whose result makes it
+// convenient to skip diagnostics within generated files.
+package generated
+
+import (
+	"go/ast"
+	"go/token"
+	"reflect"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var Analyzer = &analysis.Analyzer{
+	Name:       "generated",
+	Doc:        "detect which Go files are generated",
+	URL:        "https://pkg.go.dev/golang.org/x/tools/internal/analysisinternal/generated",
+	ResultType: reflect.TypeFor[*Result](),
+	Run: func(pass *analysis.Pass) (any, error) {
+		set := make(map[*token.File]bool)
+		for _, file := range pass.Files {
+			if ast.IsGenerated(file) {
+				set[pass.Fset.File(file.FileStart)] = true
+			}
+		}
+		return &Result{fset: pass.Fset, generatedFiles: set}, nil
+	},
+}
+
+type Result struct {
+	fset           *token.FileSet
+	generatedFiles map[*token.File]bool
+}
+
+// IsGenerated reports whether the position is within a generated file.
+func (r *Result) IsGenerated(pos token.Pos) bool {
+	return r.generatedFiles[r.fset.File(pos)]
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/goplsexport/export.go b/src/cmd/vendor/golang.org/x/tools/internal/goplsexport/export.go
new file mode 100644
index 00000000000000..2764a97fc7f3ac
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/goplsexport/export.go
@@ -0,0 +1,15 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package goplsexport provides various backdoors to not-yet-published
+// parts of x/tools that are needed by gopls.
+package goplsexport
+
+import "golang.org/x/tools/go/analysis"
+
+var (
+	ErrorsAsTypeModernizer *analysis.Analyzer // = modernize.errorsastypeAnalyzer
+	StdIteratorsModernizer *analysis.Analyzer // = modernize.stditeratorsAnalyzer
+	PlusBuildModernizer    *analysis.Analyzer // = modernize.plusbuildAnalyzer
+)
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/callee.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/callee.go
new file mode 100644
index 00000000000000..b46340c66a8210
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/callee.go
@@ -0,0 +1,867 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package inline
+
+// This file defines the analysis of the callee function.
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"slices"
+	"strings"
+
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/typeparams"
+	"golang.org/x/tools/internal/typesinternal"
+)
+
+// A Callee holds information about an inlinable function. Gob-serializable.
+type Callee struct {
+	impl gobCallee
+}
+
+func (callee *Callee) String() string { return callee.impl.Name }
+
+type gobCallee struct {
+	Content []byte // file content, compacted to a single func decl
+
+	// results of type analysis (does not reach go/types data structures)
+	PkgPath          string                 // package path of declaring package
+	Name             string                 // user-friendly name for error messages
+	Unexported       []string               // names of free objects that are unexported
+	FreeRefs         []freeRef              // locations of references to free objects
+	FreeObjs         []object               // descriptions of free objects
+	ValidForCallStmt bool                   // function body is "return expr" where expr is f() or <-ch
+	NumResults       int                    // number of results (according to type, not ast.FieldList)
+	Params           []*paramInfo           // information about parameters (incl. receiver)
+	TypeParams       []*paramInfo           // information about type parameters
+	Results          []*paramInfo           // information about result variables
+	Effects          []int                  // order in which parameters are evaluated (see calleefx)
+	HasDefer         bool                   // uses defer
+	HasBareReturn    bool                   // uses bare return in non-void function
+	Returns          [][]returnOperandFlags // metadata about result expressions for each return
+	Labels           []string               // names of all control labels
+	Falcon           falconResult           // falcon constraint system
+}
+
+// returnOperandFlags records metadata about a single result expression in a return
+// statement.
+type returnOperandFlags int
+
+const (
+	nonTrivialResult returnOperandFlags = 1 << iota // return operand has non-trivial conversion to result type
+	untypedNilResult                                // return operand is nil literal
+)
+
+// A freeRef records a reference to a free object. Gob-serializable.
+// (This means free relative to the FuncDecl as a whole, i.e. excluding parameters.)
+type freeRef struct {
+	Offset int // byte offset of the reference relative to the FuncDecl
+	Object int // index into Callee.freeObjs
+}
+
+// An object abstracts a free types.Object referenced by the callee. Gob-serializable.
+type object struct {
+	Name    string // Object.Name()
+	Kind    string // one of {var,func,const,type,pkgname,nil,builtin}
+	PkgPath string // path of object's package (or imported package if kind="pkgname")
+	PkgName string // name of object's package (or imported package if kind="pkgname")
+	// TODO(rfindley): should we also track LocalPkgName here? Do we want to
+	// preserve the local package name?
+	ValidPos bool      // Object.Pos().IsValid()
+	Shadow   shadowMap // shadowing info for the object's refs
+}
+
+// AnalyzeCallee analyzes a function that is a candidate for inlining
+// and returns a Callee that describes it. The Callee object, which is
+// serializable, can be passed to one or more subsequent calls to
+// Inline, each with a different Caller.
+//
+// This design allows separate analysis of callers and callees in the
+// golang.org/x/tools/go/analysis framework: the inlining information
+// about a callee can be recorded as a "fact".
+//
+// The content should be the actual input to the compiler, not the
+// apparent source file according to any //line directives that
+// may be present within it.
+func AnalyzeCallee(logf func(string, ...any), fset *token.FileSet, pkg *types.Package, info *types.Info, decl *ast.FuncDecl, content []byte) (*Callee, error) {
+	checkInfoFields(info)
+
+	// The client is expected to have determined that the callee
+	// is a function with a declaration (not a built-in or var).
+	fn := info.Defs[decl.Name].(*types.Func)
+	sig := fn.Type().(*types.Signature)
+
+	logf("analyzeCallee %v @ %v", fn, fset.PositionFor(decl.Pos(), false))
+
+	// Create user-friendly name ("pkg.Func" or "(pkg.T).Method")
+	var name string
+	if sig.Recv() == nil {
+		name = fmt.Sprintf("%s.%s", fn.Pkg().Name(), fn.Name())
+	} else {
+		name = fmt.Sprintf("(%s).%s", types.TypeString(sig.Recv().Type(), (*types.Package).Name), fn.Name())
+	}
+
+	if decl.Body == nil {
+		return nil, fmt.Errorf("cannot inline function %s as it has no body", name)
+	}
+
+	// Record the location of all free references in the FuncDecl.
+	// (Parameters are not free by this definition.)
+	var (
+		fieldObjs    = fieldObjs(sig)
+		freeObjIndex = make(map[types.Object]int)
+		freeObjs     []object
+		freeRefs     []freeRef // free refs that may need renaming
+		unexported   []string  // free refs to unexported objects, for later error checks
+	)
+	var f func(n ast.Node, stack []ast.Node) bool
+	var stack []ast.Node
+	stack = append(stack, decl.Type) // for scope of function itself
+	visit := func(n ast.Node, stack []ast.Node) { astutil.PreorderStack(n, stack, f) }
+	f = func(n ast.Node, stack []ast.Node) bool {
+		switch n := n.(type) {
+		case *ast.SelectorExpr:
+			// Check selections of free fields/methods.
+			if sel, ok := info.Selections[n]; ok &&
+				!within(sel.Obj().Pos(), decl) &&
+				!n.Sel.IsExported() {
+				sym := fmt.Sprintf("(%s).%s", info.TypeOf(n.X), n.Sel.Name)
+				unexported = append(unexported, sym)
+			}
+
+			// Don't recur into SelectorExpr.Sel.
+			visit(n.X, stack)
+			return false
+
+		case *ast.CompositeLit:
+			// Check for struct literals that refer to unexported fields,
+			// whether keyed or unkeyed. (Logic assumes well-typedness.)
+			litType := typeparams.Deref(info.TypeOf(n))
+			if s, ok := typeparams.CoreType(litType).(*types.Struct); ok {
+				if n.Type != nil {
+					visit(n.Type, stack)
+				}
+				for i, elt := range n.Elts {
+					var field *types.Var
+					var value ast.Expr
+					if kv, ok := elt.(*ast.KeyValueExpr); ok {
+						field = info.Uses[kv.Key.(*ast.Ident)].(*types.Var)
+						value = kv.Value
+					} else {
+						field = s.Field(i)
+						value = elt
+					}
+					if !within(field.Pos(), decl) && !field.Exported() {
+						sym := fmt.Sprintf("(%s).%s", litType, field.Name())
+						unexported = append(unexported, sym)
+					}
+
+					// Don't recur into KeyValueExpr.Key.
+					visit(value, stack)
+				}
+				return false
+			}
+
+		case *ast.Ident:
+			if obj, ok := info.Uses[n]; ok {
+				// Methods and fields are handled by SelectorExpr and CompositeLit.
+				if isField(obj) || isMethod(obj) {
+					panic(obj)
+				}
+				// Inv: id is a lexical reference.
+
+				// A reference to an unexported package-level declaration
+				// cannot be inlined into another package.
+				if !n.IsExported() &&
+					obj.Pkg() != nil && obj.Parent() == obj.Pkg().Scope() {
+					unexported = append(unexported, n.Name)
+				}
+
+				// Record free reference (incl. self-reference).
+				if obj == fn || !within(obj.Pos(), decl) {
+					objidx, ok := freeObjIndex[obj]
+					if !ok {
+						objidx = len(freeObjIndex)
+						var pkgPath, pkgName string
+						if pn, ok := obj.(*types.PkgName); ok {
+							pkgPath = pn.Imported().Path()
+							pkgName = pn.Imported().Name()
+						} else if obj.Pkg() != nil {
+							pkgPath = obj.Pkg().Path()
+							pkgName = obj.Pkg().Name()
+						}
+						freeObjs = append(freeObjs, object{
+							Name:     obj.Name(),
+							Kind:     objectKind(obj),
+							PkgName:  pkgName,
+							PkgPath:  pkgPath,
+							ValidPos: obj.Pos().IsValid(),
+						})
+						freeObjIndex[obj] = objidx
+					}
+
+					freeObjs[objidx].Shadow = freeObjs[objidx].Shadow.add(info, fieldObjs, obj.Name(), stack)
+
+					freeRefs = append(freeRefs, freeRef{
+						Offset: int(n.Pos() - decl.Pos()),
+						Object: objidx,
+					})
+				}
+			}
+		}
+		return true
+	}
+	visit(decl, stack)
+
+	// Analyze callee body for "return expr" form,
+	// where expr is f() or <-ch. These forms are
+	// safe to inline as a standalone statement.
+	validForCallStmt := false
+	if len(decl.Body.List) != 1 {
+		// not just a return statement
+	} else if ret, ok := decl.Body.List[0].(*ast.ReturnStmt); ok && len(ret.Results) == 1 {
+		validForCallStmt = func() bool {
+			switch expr := ast.Unparen(ret.Results[0]).(type) {
+			case *ast.CallExpr: // f(x)
+				callee := typeutil.Callee(info, expr)
+				if callee == nil {
+					return false // conversion T(x)
+				}
+
+				// The only non-void built-in functions that may be
+				// called as a statement are copy and recover
+				// (though arguably a call to recover should never
+				// be inlined as that changes its behavior).
+				if builtin, ok := callee.(*types.Builtin); ok {
+					return builtin.Name() == "copy" ||
+						builtin.Name() == "recover"
+				}
+
+				return true // ordinary call f()
+
+			case *ast.UnaryExpr: // <-x
+				return expr.Op == token.ARROW // channel receive <-ch
+			}
+
+			// No other expressions are valid statements.
+			return false
+		}()
+	}
+
+	// Record information about control flow in the callee
+	// (but not any nested functions).
+	var (
+		hasDefer      = false
+		hasBareReturn = false
+		returnInfo    [][]returnOperandFlags
+		labels        []string
+	)
+	ast.Inspect(decl.Body, func(n ast.Node) bool {
+		switch n := n.(type) {
+		case *ast.FuncLit:
+			return false // prune traversal
+		case *ast.DeferStmt:
+			hasDefer = true
+		case *ast.LabeledStmt:
+			labels = append(labels, n.Label.Name)
+		case *ast.ReturnStmt:
+
+			// Are implicit assignment conversions
+			// to result variables all trivial?
+			var resultInfo []returnOperandFlags
+			if len(n.Results) > 0 {
+				argInfo := func(i int) (ast.Expr, types.Type) {
+					expr := n.Results[i]
+					return expr, info.TypeOf(expr)
+				}
+				if len(n.Results) == 1 && sig.Results().Len() > 1 {
+					// Spread return: return f() where f.Results > 1.
+					tuple := info.TypeOf(n.Results[0]).(*types.Tuple)
+					argInfo = func(i int) (ast.Expr, types.Type) {
+						return nil, tuple.At(i).Type()
+					}
+				}
+				for i := range sig.Results().Len() {
+					expr, typ := argInfo(i)
+					var flags returnOperandFlags
+					if typ == types.Typ[types.UntypedNil] { // untyped nil is preserved by go/types
+						flags |= untypedNilResult
+					}
+					if !trivialConversion(info.Types[expr].Value, typ, sig.Results().At(i).Type()) {
+						flags |= nonTrivialResult
+					}
+					resultInfo = append(resultInfo, flags)
+				}
+			} else if sig.Results().Len() > 0 {
+				hasBareReturn = true
+			}
+			returnInfo = append(returnInfo, resultInfo)
+		}
+		return true
+	})
+
+	// Reject attempts to inline cgo-generated functions.
+	for _, obj := range freeObjs {
+		// There are others (iconst fconst sconst fpvar macro)
+		// but this is probably sufficient.
+		if strings.HasPrefix(obj.Name, "_Cfunc_") ||
+			strings.HasPrefix(obj.Name, "_Ctype_") ||
+			strings.HasPrefix(obj.Name, "_Cvar_") {
+			return nil, fmt.Errorf("cannot inline cgo-generated functions")
+		}
+	}
+
+	// Compact content to just the FuncDecl.
+	//
+	// As a space optimization, we don't retain the complete
+	// callee file content; all we need is "package _; func f() { ... }".
+	// This reduces the size of analysis facts.
+	//
+	// Offsets in the callee information are "relocatable"
+	// since they are all relative to the FuncDecl.
+
+	content = append([]byte("package _\n"),
+		content[offsetOf(fset, decl.Pos()):offsetOf(fset, decl.End())]...)
+	// Sanity check: re-parse the compacted content.
+	if _, _, err := parseCompact(content); err != nil {
+		return nil, err
+	}
+
+	params, results, effects, falcon := analyzeParams(logf, fset, info, decl)
+	tparams := analyzeTypeParams(logf, fset, info, decl)
+	return &Callee{gobCallee{
+		Content:          content,
+		PkgPath:          pkg.Path(),
+		Name:             name,
+		Unexported:       unexported,
+		FreeObjs:         freeObjs,
+		FreeRefs:         freeRefs,
+		ValidForCallStmt: validForCallStmt,
+		NumResults:       sig.Results().Len(),
+		Params:           params,
+		TypeParams:       tparams,
+		Results:          results,
+		Effects:          effects,
+		HasDefer:         hasDefer,
+		HasBareReturn:    hasBareReturn,
+		Returns:          returnInfo,
+		Labels:           labels,
+		Falcon:           falcon,
+	}}, nil
+}
+
+// parseCompact parses a Go source file of the form "package _\n func f() { ... }"
+// and returns the sole function declaration.
+func parseCompact(content []byte) (*token.FileSet, *ast.FuncDecl, error) {
+	fset := token.NewFileSet()
+	const mode = parser.ParseComments | parser.SkipObjectResolution | parser.AllErrors
+	f, err := parser.ParseFile(fset, "callee.go", content, mode)
+	if err != nil {
+		return nil, nil, fmt.Errorf("internal error: cannot compact file: %v", err)
+	}
+	return fset, f.Decls[0].(*ast.FuncDecl), nil
+}
+
+// A paramInfo records information about a callee receiver, parameter, or result variable.
+type paramInfo struct {
+	Name        string    // parameter name (may be blank, or even "")
+	Index       int       // index within signature
+	IsResult    bool      // false for receiver or parameter, true for result variable
+	IsInterface bool      // parameter has a (non-type parameter) interface type
+	Assigned    bool      // parameter appears on left side of an assignment statement
+	Escapes     bool      // parameter has its address taken
+	Refs        []refInfo // information about references to parameter within body
+	Shadow      shadowMap // shadowing info for the above refs; see [shadowMap]
+	FalconType  string    // name of this parameter's type (if basic) in the falcon system
+}
+
+type refInfo struct {
+	Offset           int  // FuncDecl-relative byte offset of parameter ref within body
+	Assignable       bool // ref appears in context of assignment to known type
+	IfaceAssignment  bool // ref is being assigned to an interface
+	AffectsInference bool // ref type may affect type inference
+	// IsSelectionOperand indicates whether the parameter reference is the
+	// operand of a selection (param.f). If so, and param's argument is itself
+	// a receiver parameter (a common case), we don't need to desugar (&v or *ptr)
+	// the selection: if param.Method is a valid selection, then so is param.fieldOrMethod.
+	IsSelectionOperand bool
+}
+
+// analyzeParams computes information about parameters of the function declared by decl,
+// including a simple "address taken" escape analysis.
+//
+// It returns two new arrays, one of the receiver and parameters, and
+// the other of the result variables of the function.
+//
+// The input must be well-typed.
+func analyzeParams(logf func(string, ...any), fset *token.FileSet, info *types.Info, decl *ast.FuncDecl) (params, results []*paramInfo, effects []int, _ falconResult) {
+	sig := signature(fset, info, decl)
+
+	paramInfos := make(map[*types.Var]*paramInfo)
+	{
+		newParamInfo := func(param *types.Var, isResult bool) *paramInfo {
+			info := ¶mInfo{
+				Name:        param.Name(),
+				IsResult:    isResult,
+				Index:       len(paramInfos),
+				IsInterface: isNonTypeParamInterface(param.Type()),
+			}
+			paramInfos[param] = info
+			return info
+		}
+		if sig.Recv() != nil {
+			params = append(params, newParamInfo(sig.Recv(), false))
+		}
+		for i := 0; i < sig.Params().Len(); i++ {
+			params = append(params, newParamInfo(sig.Params().At(i), false))
+		}
+		for i := 0; i < sig.Results().Len(); i++ {
+			results = append(results, newParamInfo(sig.Results().At(i), true))
+		}
+	}
+
+	// Search function body for operations &x, x.f(), and x = y
+	// where x is a parameter, and record it.
+	escape(info, decl, func(v *types.Var, escapes bool) {
+		if info := paramInfos[v]; info != nil {
+			if escapes {
+				info.Escapes = true
+			} else {
+				info.Assigned = true
+			}
+		}
+	})
+
+	// Record locations of all references to parameters.
+	// And record the set of intervening definitions for each parameter.
+	//
+	// TODO(adonovan): combine this traversal with the one that computes
+	// FreeRefs. The tricky part is that calleefx needs this one first.
+	fieldObjs := fieldObjs(sig)
+	var stack []ast.Node
+	stack = append(stack, decl.Type) // for scope of function itself
+	astutil.PreorderStack(decl.Body, stack, func(n ast.Node, stack []ast.Node) bool {
+		if id, ok := n.(*ast.Ident); ok {
+			if v, ok := info.Uses[id].(*types.Var); ok {
+				if pinfo, ok := paramInfos[v]; ok {
+					// Record ref information, and any intervening (shadowing) names.
+					//
+					// If the parameter v has an interface type, and the reference id
+					// appears in a context where assignability rules apply, there may be
+					// an implicit interface-to-interface widening. In that case it is
+					// not necessary to insert an explicit conversion from the argument
+					// to the parameter's type.
+					//
+					// Contrapositively, if param is not an interface type, then the
+					// assignment may lose type information, for example in the case that
+					// the substituted expression is an untyped constant or unnamed type.
+					stack = append(stack, n) // (the two calls below want n)
+					assignable, ifaceAssign, affectsInference := analyzeAssignment(info, stack)
+					ref := refInfo{
+						Offset:             int(n.Pos() - decl.Pos()),
+						Assignable:         assignable,
+						IfaceAssignment:    ifaceAssign,
+						AffectsInference:   affectsInference,
+						IsSelectionOperand: isSelectionOperand(stack),
+					}
+					pinfo.Refs = append(pinfo.Refs, ref)
+					pinfo.Shadow = pinfo.Shadow.add(info, fieldObjs, pinfo.Name, stack)
+				}
+			}
+		}
+		return true
+	})
+
+	// Compute subset and order of parameters that are strictly evaluated.
+	// (Depends on Refs computed above.)
+	effects = calleefx(info, decl.Body, paramInfos)
+	logf("effects list = %v", effects)
+
+	falcon := falcon(logf, fset, paramInfos, info, decl)
+
+	return params, results, effects, falcon
+}
+
+// analyzeTypeParams computes information about the type parameters of the function declared by decl.
+func analyzeTypeParams(_ logger, fset *token.FileSet, info *types.Info, decl *ast.FuncDecl) []*paramInfo {
+	sig := signature(fset, info, decl)
+	paramInfos := make(map[*types.TypeName]*paramInfo)
+	var params []*paramInfo
+	collect := func(tpl *types.TypeParamList) {
+		for i := range tpl.Len() {
+			typeName := tpl.At(i).Obj()
+			info := ¶mInfo{Name: typeName.Name()}
+			params = append(params, info)
+			paramInfos[typeName] = info
+		}
+	}
+	collect(sig.RecvTypeParams())
+	collect(sig.TypeParams())
+
+	// Find references.
+	// We don't care about most of the properties that matter for parameter references:
+	// a type is immutable, cannot have its address taken, and does not undergo conversions.
+	// TODO(jba): can we nevertheless combine this with the traversal in analyzeParams?
+	var stack []ast.Node
+	stack = append(stack, decl.Type) // for scope of function itself
+	astutil.PreorderStack(decl.Body, stack, func(n ast.Node, stack []ast.Node) bool {
+		if id, ok := n.(*ast.Ident); ok {
+			if v, ok := info.Uses[id].(*types.TypeName); ok {
+				if pinfo, ok := paramInfos[v]; ok {
+					ref := refInfo{Offset: int(n.Pos() - decl.Pos())}
+					pinfo.Refs = append(pinfo.Refs, ref)
+					pinfo.Shadow = pinfo.Shadow.add(info, nil, pinfo.Name, stack)
+				}
+			}
+		}
+		return true
+	})
+	return params
+}
+
+func signature(fset *token.FileSet, info *types.Info, decl *ast.FuncDecl) *types.Signature {
+	fnobj, ok := info.Defs[decl.Name]
+	if !ok {
+		panic(fmt.Sprintf("%s: no func object for %q",
+			fset.PositionFor(decl.Name.Pos(), false), decl.Name)) // ill-typed?
+	}
+	return fnobj.Type().(*types.Signature)
+}
+
+// -- callee helpers --
+
+// analyzeAssignment looks at the given stack, and analyzes certain
+// attributes of the innermost expression.
+//
+// In all cases we 'fail closed' when we cannot detect (or for simplicity
+// choose not to detect) the condition in question, meaning we err on the side
+// of the more restrictive rule. This is noted for each result below.
+//
+//   - assignable reports whether the expression is used in a position where
+//     assignability rules apply, such as in an actual assignment, as call
+//     argument, or in a send to a channel. Defaults to 'false'. If assignable
+//     is false, the other two results are irrelevant.
+//   - ifaceAssign reports whether that assignment is to an interface type.
+//     This is important as we want to preserve the concrete type in that
+//     assignment. Defaults to 'true'. Notably, if the assigned type is a type
+//     parameter, we assume that it could have interface type.
+//   - affectsInference is (somewhat vaguely) defined as whether or not the
+//     type of the operand may affect the type of the surrounding syntax,
+//     through type inference. It is infeasible to completely reverse engineer
+//     type inference, so we over approximate: if the expression is an argument
+//     to a call to a generic function (but not method!) that uses type
+//     parameters, assume that unification of that argument may affect the
+//     inferred types.
+func analyzeAssignment(info *types.Info, stack []ast.Node) (assignable, ifaceAssign, affectsInference bool) {
+	remaining, parent, expr := exprContext(stack)
+	if parent == nil {
+		return false, false, false
+	}
+
+	// TODO(golang/go#70638): simplify when types.Info records implicit conversions.
+
+	// Types do not need to match for assignment to a variable.
+	if assign, ok := parent.(*ast.AssignStmt); ok {
+		for i, v := range assign.Rhs {
+			if v == expr {
+				if i >= len(assign.Lhs) {
+					return false, false, false // ill typed
+				}
+				// Check to see if the assignment is to an interface type.
+				if i < len(assign.Lhs) {
+					// TODO: We could handle spread calls here, but in current usage expr
+					// is an ident.
+					if id, _ := assign.Lhs[i].(*ast.Ident); id != nil && info.Defs[id] != nil {
+						// Types must match for a defining identifier in a short variable
+						// declaration.
+						return false, false, false
+					}
+					// In all other cases, types should be known.
+					typ := info.TypeOf(assign.Lhs[i])
+					return true, typ == nil || types.IsInterface(typ), false
+				}
+				// Default:
+				return assign.Tok == token.ASSIGN, true, false
+			}
+		}
+	}
+
+	// Types do not need to match for an initializer with known type.
+	if spec, ok := parent.(*ast.ValueSpec); ok && spec.Type != nil {
+		if slices.Contains(spec.Values, expr) {
+			typ := info.TypeOf(spec.Type)
+			return true, typ == nil || types.IsInterface(typ), false
+		}
+	}
+
+	// Types do not need to match for index expressions.
+	if ix, ok := parent.(*ast.IndexExpr); ok {
+		if ix.Index == expr {
+			typ := info.TypeOf(ix.X)
+			if typ == nil {
+				return true, true, false
+			}
+			m, _ := typeparams.CoreType(typ).(*types.Map)
+			return true, m == nil || types.IsInterface(m.Key()), false
+		}
+	}
+
+	// Types do not need to match for composite literal keys, values, or
+	// fields.
+	if kv, ok := parent.(*ast.KeyValueExpr); ok {
+		var under types.Type
+		if len(remaining) > 0 {
+			if complit, ok := remaining[len(remaining)-1].(*ast.CompositeLit); ok {
+				if typ := info.TypeOf(complit); typ != nil {
+					// Unpointer to allow for pointers to slices or arrays, which are
+					// permitted as the types of nested composite literals without a type
+					// name.
+					under = typesinternal.Unpointer(typeparams.CoreType(typ))
+				}
+			}
+		}
+		if kv.Key == expr { // M{expr: ...}: assign to map key
+			m, _ := under.(*types.Map)
+			return true, m == nil || types.IsInterface(m.Key()), false
+		}
+		if kv.Value == expr {
+			switch under := under.(type) {
+			case interface{ Elem() types.Type }: // T{...: expr}: assign to map/array/slice element
+				return true, types.IsInterface(under.Elem()), false
+			case *types.Struct: // Struct{k: expr}
+				if id, _ := kv.Key.(*ast.Ident); id != nil {
+					for fi := range under.NumFields() {
+						field := under.Field(fi)
+						if info.Uses[id] == field {
+							return true, types.IsInterface(field.Type()), false
+						}
+					}
+				}
+			default:
+				return true, true, false
+			}
+		}
+	}
+	if lit, ok := parent.(*ast.CompositeLit); ok {
+		for i, v := range lit.Elts {
+			if v == expr {
+				typ := info.TypeOf(lit)
+				if typ == nil {
+					return true, true, false
+				}
+				// As in the KeyValueExpr case above, unpointer to handle pointers to
+				// array/slice literals.
+				under := typesinternal.Unpointer(typeparams.CoreType(typ))
+				switch under := under.(type) {
+				case interface{ Elem() types.Type }: // T{expr}: assign to map/array/slice element
+					return true, types.IsInterface(under.Elem()), false
+				case *types.Struct: // Struct{expr}: assign to unkeyed struct field
+					if i < under.NumFields() {
+						return true, types.IsInterface(under.Field(i).Type()), false
+					}
+				}
+				return true, true, false
+			}
+		}
+	}
+
+	// Types do not need to match for values sent to a channel.
+	if send, ok := parent.(*ast.SendStmt); ok {
+		if send.Value == expr {
+			typ := info.TypeOf(send.Chan)
+			if typ == nil {
+				return true, true, false
+			}
+			ch, _ := typeparams.CoreType(typ).(*types.Chan)
+			return true, ch == nil || types.IsInterface(ch.Elem()), false
+		}
+	}
+
+	// Types do not need to match for an argument to a call, unless the
+	// corresponding parameter has type parameters, as in that case the
+	// argument type may affect inference.
+	if call, ok := parent.(*ast.CallExpr); ok {
+		if _, ok := isConversion(info, call); ok {
+			return false, false, false // redundant conversions are handled at the call site
+		}
+		// Ordinary call. Could be a call of a func, builtin, or function value.
+		for i, arg := range call.Args {
+			if arg == expr {
+				typ := info.TypeOf(call.Fun)
+				if typ == nil {
+					return true, true, false
+				}
+				sig, _ := typeparams.CoreType(typ).(*types.Signature)
+				if sig != nil {
+					// Find the relevant parameter type, accounting for variadics.
+					paramType := paramTypeAtIndex(sig, call, i)
+					ifaceAssign := paramType == nil || types.IsInterface(paramType)
+					affectsInference := false
+					if fn := typeutil.StaticCallee(info, call); fn != nil {
+						if sig2 := fn.Type().(*types.Signature); sig2.Recv() == nil {
+							originParamType := paramTypeAtIndex(sig2, call, i)
+							affectsInference = originParamType == nil || new(typeparams.Free).Has(originParamType)
+						}
+					}
+					return true, ifaceAssign, affectsInference
+				}
+			}
+		}
+	}
+
+	return false, false, false
+}
+
+// paramTypeAtIndex returns the effective parameter type at the given argument
+// index in call, if valid.
+func paramTypeAtIndex(sig *types.Signature, call *ast.CallExpr, index int) types.Type {
+	if plen := sig.Params().Len(); sig.Variadic() && index >= plen-1 && !call.Ellipsis.IsValid() {
+		if s, ok := sig.Params().At(plen - 1).Type().(*types.Slice); ok {
+			return s.Elem()
+		}
+	} else if index < plen {
+		return sig.Params().At(index).Type()
+	}
+	return nil // ill typed
+}
+
+// exprContext returns the innermost parent->child expression nodes for the
+// given outer-to-inner stack, after stripping parentheses, along with the
+// remaining stack up to the parent node.
+//
+// If no such context exists, returns (nil, nil, nil).
+func exprContext(stack []ast.Node) (remaining []ast.Node, parent ast.Node, expr ast.Expr) {
+	expr, _ = stack[len(stack)-1].(ast.Expr)
+	if expr == nil {
+		return nil, nil, nil
+	}
+	i := len(stack) - 2
+	for ; i >= 0; i-- {
+		if pexpr, ok := stack[i].(*ast.ParenExpr); ok {
+			expr = pexpr
+		} else {
+			parent = stack[i]
+			break
+		}
+	}
+	if parent == nil {
+		return nil, nil, nil
+	}
+	// inv: i is the index of parent in the stack.
+	return stack[:i], parent, expr
+}
+
+// isSelectionOperand reports whether the innermost node of stack is operand
+// (x) of a selection x.f.
+func isSelectionOperand(stack []ast.Node) bool {
+	_, parent, expr := exprContext(stack)
+	if parent == nil {
+		return false
+	}
+	sel, ok := parent.(*ast.SelectorExpr)
+	return ok && sel.X == expr
+}
+
+// A shadowMap records information about shadowing at any of the parameter's
+// references within the callee decl.
+//
+// For each name shadowed at a reference to the parameter within the callee
+// body, shadow map records the 1-based index of the callee decl parameter
+// causing the shadowing, or -1, if the shadowing is not due to a callee decl.
+// A value of zero (or missing) indicates no shadowing. By convention,
+// self-shadowing is excluded from the map.
+//
+// For example, in the following callee
+//
+//	func f(a, b int) int {
+//		c := 2 + b
+//		return a + c
+//	}
+//
+// the shadow map of a is {b: 2, c: -1}, because b is shadowed by the 2nd
+// parameter. The shadow map of b is {a: 1}, because c is not shadowed at the
+// use of b.
+type shadowMap map[string]int
+
+// add returns the [shadowMap] augmented by the set of names
+// locally shadowed at the location of the reference in the callee
+// (identified by the stack). The name of the reference itself is
+// excluded.
+//
+// These shadowed names may not be used in a replacement expression
+// for the reference.
+func (s shadowMap) add(info *types.Info, paramIndexes map[types.Object]int, exclude string, stack []ast.Node) shadowMap {
+	for _, n := range stack {
+		if scope := scopeFor(info, n); scope != nil {
+			for _, name := range scope.Names() {
+				if name != exclude {
+					if s == nil {
+						s = make(shadowMap)
+					}
+					obj := scope.Lookup(name)
+					if idx, ok := paramIndexes[obj]; ok {
+						s[name] = idx + 1
+					} else {
+						s[name] = -1
+					}
+				}
+			}
+		}
+	}
+	return s
+}
+
+// fieldObjs returns a map of each types.Object defined by the given signature
+// to its index in the parameter list. Parameters with missing or blank name
+// are skipped.
+func fieldObjs(sig *types.Signature) map[types.Object]int {
+	m := make(map[types.Object]int)
+	for i := range sig.Params().Len() {
+		if p := sig.Params().At(i); p.Name() != "" && p.Name() != "_" {
+			m[p] = i
+		}
+	}
+	return m
+}
+
+func isField(obj types.Object) bool {
+	if v, ok := obj.(*types.Var); ok && v.IsField() {
+		return true
+	}
+	return false
+}
+
+func isMethod(obj types.Object) bool {
+	if f, ok := obj.(*types.Func); ok && f.Type().(*types.Signature).Recv() != nil {
+		return true
+	}
+	return false
+}
+
+// -- serialization --
+
+var (
+	_ gob.GobEncoder = (*Callee)(nil)
+	_ gob.GobDecoder = (*Callee)(nil)
+)
+
+func (callee *Callee) GobEncode() ([]byte, error) {
+	var out bytes.Buffer
+	if err := gob.NewEncoder(&out).Encode(callee.impl); err != nil {
+		return nil, err
+	}
+	return out.Bytes(), nil
+}
+
+func (callee *Callee) GobDecode(data []byte) error {
+	return gob.NewDecoder(bytes.NewReader(data)).Decode(&callee.impl)
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/calleefx.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/calleefx.go
new file mode 100644
index 00000000000000..001bf61e93e5e9
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/calleefx.go
@@ -0,0 +1,349 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package inline
+
+// This file defines the analysis of callee effects.
+
+import (
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"golang.org/x/tools/internal/typesinternal"
+)
+
+const (
+	rinf = -1 //  R∞: arbitrary read from memory
+	winf = -2 //  W∞: arbitrary write to memory (or unknown control)
+)
+
+// calleefx returns a list of parameter indices indicating the order
+// in which parameters are first referenced during evaluation of the
+// callee, relative both to each other and to other effects of the
+// callee (if any), such as arbitrary reads (rinf) and arbitrary
+// effects (winf), including unknown control flow. Each parameter
+// that is referenced appears once in the list.
+//
+// For example, the effects list of this function:
+//
+//	func f(x, y, z int) int {
+//	    return y + x + g() + z
+//	}
+//
+// is [1 0 -2 2], indicating reads of y and x, followed by the unknown
+// effects of the g() call, and finally the read of parameter z. This
+// information is used during inlining to ascertain when it is safe
+// for parameter references to be replaced by their corresponding
+// argument expressions. Such substitutions are permitted only when
+// they do not cause "write" operations (those with effects) to
+// commute with "read" operations (those that have no effect but are
+// not pure). Impure operations may be reordered with other impure
+// operations, and pure operations may be reordered arbitrarily.
+//
+// The analysis ignores the effects of runtime panics, on the
+// assumption that well-behaved programs shouldn't encounter them.
+func calleefx(info *types.Info, body *ast.BlockStmt, paramInfos map[*types.Var]*paramInfo) []int {
+	// This traversal analyzes the callee's statements (in syntax
+	// form, though one could do better with SSA) to compute the
+	// sequence of events of the following kinds:
+	//
+	// 1  read of a parameter variable.
+	// 2. reads from other memory.
+	// 3. writes to memory
+
+	var effects []int // indices of parameters, or rinf/winf (-ve)
+	seen := make(map[int]bool)
+	effect := func(i int) {
+		if !seen[i] {
+			seen[i] = true
+			effects = append(effects, i)
+		}
+	}
+
+	// unknown is called for statements of unknown effects (or control).
+	unknown := func() {
+		effect(winf)
+
+		// Ensure that all remaining parameters are "seen"
+		// after we go into the unknown (unless they are
+		// unreferenced by the function body). This lets us
+		// not bother implementing the complete traversal into
+		// control structures.
+		//
+		// TODO(adonovan): add them in a deterministic order.
+		// (This is not a bug but determinism is good.)
+		for _, pinfo := range paramInfos {
+			if !pinfo.IsResult && len(pinfo.Refs) > 0 {
+				effect(pinfo.Index)
+			}
+		}
+	}
+
+	var visitExpr func(n ast.Expr)
+	var visitStmt func(n ast.Stmt) bool
+	visitExpr = func(n ast.Expr) {
+		switch n := n.(type) {
+		case *ast.Ident:
+			if v, ok := info.Uses[n].(*types.Var); ok && !v.IsField() {
+				// Use of global?
+				if v.Parent() == v.Pkg().Scope() {
+					effect(rinf) // read global var
+				}
+
+				// Use of parameter?
+				if pinfo, ok := paramInfos[v]; ok && !pinfo.IsResult {
+					effect(pinfo.Index) // read parameter var
+				}
+
+				// Use of local variables is ok.
+			}
+
+		case *ast.BasicLit:
+			// no effect
+
+		case *ast.FuncLit:
+			// A func literal has no read or write effect
+			// until called, and (most) function calls are
+			// considered to have arbitrary effects.
+			// So, no effect.
+
+		case *ast.CompositeLit:
+			for _, elt := range n.Elts {
+				visitExpr(elt) // note: visits KeyValueExpr
+			}
+
+		case *ast.ParenExpr:
+			visitExpr(n.X)
+
+		case *ast.SelectorExpr:
+			if seln, ok := info.Selections[n]; ok {
+				visitExpr(n.X)
+
+				// See types.SelectionKind for background.
+				switch seln.Kind() {
+				case types.MethodExpr:
+					// A method expression T.f acts like a
+					// reference to a func decl,
+					// so it doesn't read x until called.
+
+				case types.MethodVal, types.FieldVal:
+					// A field or method value selection x.f
+					// reads x if the selection indirects a pointer.
+
+					if indirectSelection(seln) {
+						effect(rinf)
+					}
+				}
+			} else {
+				// qualified identifier: treat like unqualified
+				visitExpr(n.Sel)
+			}
+
+		case *ast.IndexExpr:
+			if tv := info.Types[n.Index]; tv.IsType() {
+				// no effect (G[T] instantiation)
+			} else {
+				visitExpr(n.X)
+				visitExpr(n.Index)
+				switch tv.Type.Underlying().(type) {
+				case *types.Slice, *types.Pointer: // []T, *[n]T (not string, [n]T)
+					effect(rinf) // indirect read of slice/array element
+				}
+			}
+
+		case *ast.IndexListExpr:
+			// no effect (M[K,V] instantiation)
+
+		case *ast.SliceExpr:
+			visitExpr(n.X)
+			visitExpr(n.Low)
+			visitExpr(n.High)
+			visitExpr(n.Max)
+
+		case *ast.TypeAssertExpr:
+			visitExpr(n.X)
+
+		case *ast.CallExpr:
+			if info.Types[n.Fun].IsType() {
+				// conversion T(x)
+				visitExpr(n.Args[0])
+			} else {
+				// call f(args)
+				visitExpr(n.Fun)
+				for i, arg := range n.Args {
+					if i == 0 && info.Types[arg].IsType() {
+						continue // new(T), make(T, n)
+					}
+					visitExpr(arg)
+				}
+
+				// The pure built-ins have no effects beyond
+				// those of their operands (not even memory reads).
+				// All other calls have unknown effects.
+				if !typesinternal.CallsPureBuiltin(info, n) {
+					unknown() // arbitrary effects
+				}
+			}
+
+		case *ast.StarExpr:
+			visitExpr(n.X)
+			effect(rinf) // *ptr load or store depends on state of heap
+
+		case *ast.UnaryExpr: // + - ! ^ & ~ <-
+			visitExpr(n.X)
+			if n.Op == token.ARROW {
+				unknown() // effect: channel receive
+			}
+
+		case *ast.BinaryExpr:
+			visitExpr(n.X)
+			visitExpr(n.Y)
+
+		case *ast.KeyValueExpr:
+			visitExpr(n.Key) // may be a struct field
+			visitExpr(n.Value)
+
+		case *ast.BadExpr:
+			// no effect
+
+		case nil:
+			// optional subtree
+
+		default:
+			// type syntax: unreachable given traversal
+			panic(n)
+		}
+	}
+
+	// visitStmt's result indicates the continuation:
+	// false for return, true for the next statement.
+	//
+	// We could treat return as an unknown, but this way
+	// yields definite effects for simple sequences like
+	// {S1; S2; return}, so unreferenced parameters are
+	// not spuriously added to the effects list, and thus
+	// not spuriously disqualified from elimination.
+	visitStmt = func(n ast.Stmt) bool {
+		switch n := n.(type) {
+		case *ast.DeclStmt:
+			decl := n.Decl.(*ast.GenDecl)
+			for _, spec := range decl.Specs {
+				switch spec := spec.(type) {
+				case *ast.ValueSpec:
+					for _, v := range spec.Values {
+						visitExpr(v)
+					}
+
+				case *ast.TypeSpec:
+					// no effect
+				}
+			}
+
+		case *ast.LabeledStmt:
+			return visitStmt(n.Stmt)
+
+		case *ast.ExprStmt:
+			visitExpr(n.X)
+
+		case *ast.SendStmt:
+			visitExpr(n.Chan)
+			visitExpr(n.Value)
+			unknown() // effect: channel send
+
+		case *ast.IncDecStmt:
+			visitExpr(n.X)
+			unknown() // effect: variable increment
+
+		case *ast.AssignStmt:
+			for _, lhs := range n.Lhs {
+				visitExpr(lhs)
+			}
+			for _, rhs := range n.Rhs {
+				visitExpr(rhs)
+			}
+			for _, lhs := range n.Lhs {
+				id, _ := lhs.(*ast.Ident)
+				if id != nil && id.Name == "_" {
+					continue // blank assign has no effect
+				}
+				if n.Tok == token.DEFINE && id != nil && info.Defs[id] != nil {
+					continue // new var declared by := has no effect
+				}
+				unknown() // assignment to existing var
+				break
+			}
+
+		case *ast.GoStmt:
+			visitExpr(n.Call.Fun)
+			for _, arg := range n.Call.Args {
+				visitExpr(arg)
+			}
+			unknown() // effect: create goroutine
+
+		case *ast.DeferStmt:
+			visitExpr(n.Call.Fun)
+			for _, arg := range n.Call.Args {
+				visitExpr(arg)
+			}
+			unknown() // effect: push defer
+
+		case *ast.ReturnStmt:
+			for _, res := range n.Results {
+				visitExpr(res)
+			}
+			return false
+
+		case *ast.BlockStmt:
+			for _, stmt := range n.List {
+				if !visitStmt(stmt) {
+					return false
+				}
+			}
+
+		case *ast.BranchStmt:
+			unknown() // control flow
+
+		case *ast.IfStmt:
+			visitStmt(n.Init)
+			visitExpr(n.Cond)
+			unknown() // control flow
+
+		case *ast.SwitchStmt:
+			visitStmt(n.Init)
+			visitExpr(n.Tag)
+			unknown() // control flow
+
+		case *ast.TypeSwitchStmt:
+			visitStmt(n.Init)
+			visitStmt(n.Assign)
+			unknown() // control flow
+
+		case *ast.SelectStmt:
+			unknown() // control flow
+
+		case *ast.ForStmt:
+			visitStmt(n.Init)
+			visitExpr(n.Cond)
+			unknown() // control flow
+
+		case *ast.RangeStmt:
+			visitExpr(n.X)
+			unknown() // control flow
+
+		case *ast.EmptyStmt, *ast.BadStmt:
+			// no effect
+
+		case nil:
+			// optional subtree
+
+		default:
+			panic(n)
+		}
+		return true
+	}
+	visitStmt(body)
+
+	return effects
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/doc.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/doc.go
new file mode 100644
index 00000000000000..6bb4cef055dd56
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/doc.go
@@ -0,0 +1,288 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package inline implements inlining of Go function calls.
+
+The client provides information about the caller and callee,
+including the source text, syntax tree, and type information, and
+the inliner returns the modified source file for the caller, or an
+error if the inlining operation is invalid (for example because the
+function body refers to names that are inaccessible to the caller).
+
+Although this interface demands more information from the client
+than might seem necessary, it enables smoother integration with
+existing batch and interactive tools that have their own ways of
+managing the processes of reading, parsing, and type-checking
+packages. In particular, this package does not assume that the
+caller and callee belong to the same token.FileSet or
+types.Importer realms.
+
+There are many aspects to a function call. It is the only construct
+that can simultaneously bind multiple variables of different
+explicit types, with implicit assignment conversions. (Neither var
+nor := declarations can do that.) It defines the scope of control
+labels, of return statements, and of defer statements. Arguments
+and results of function calls may be tuples even though tuples are
+not first-class values in Go, and a tuple-valued call expression
+may be "spread" across the argument list of a call or the operands
+of a return statement. All these unique features mean that in the
+general case, not everything that can be expressed by a function
+call can be expressed without one.
+
+So, in general, inlining consists of modifying a function or method
+call expression f(a1, ..., an) so that the name of the function f
+is replaced ("literalized") by a literal copy of the function
+declaration, with free identifiers suitably modified to use the
+locally appropriate identifiers or perhaps constant argument
+values.
+
+Inlining must not change the semantics of the call. Semantics
+preservation is crucial for clients such as codebase maintenance
+tools that automatically inline all calls to designated functions
+on a large scale. Such tools must not introduce subtle behavior
+changes. (Fully inlining a call is dynamically observable using
+reflection over the call stack, but this exception to the rule is
+explicitly allowed.)
+
+In many cases it is possible to entirely replace ("reduce") the
+call by a copy of the function's body in which parameters have been
+replaced by arguments. The inliner supports a number of reduction
+strategies, and we expect this set to grow. Nonetheless, sound
+reduction is surprisingly tricky.
+
+The inliner is in some ways like an optimizing compiler. A compiler
+is considered correct if it doesn't change the meaning of the
+program in translation from source language to target language. An
+optimizing compiler exploits the particulars of the input to
+generate better code, where "better" usually means more efficient.
+When a case is found in which it emits suboptimal code, the
+compiler is improved to recognize more cases, or more rules, and
+more exceptions to rules; this process has no end. Inlining is
+similar except that "better" code means tidier code. The baseline
+translation (literalization) is correct, but there are endless
+rules--and exceptions to rules--by which the output can be
+improved.
+
+The following section lists some of the challenges, and ways in
+which they can be addressed.
+
+  - All effects of the call argument expressions must be preserved,
+    both in their number (they must not be eliminated or repeated),
+    and in their order (both with respect to other arguments, and any
+    effects in the callee function).
+
+    This must be the case even if the corresponding parameters are
+    never referenced, are referenced multiple times, referenced in
+    a different order from the arguments, or referenced within a
+    nested function that may be executed an arbitrary number of
+    times.
+
+    Currently, parameter replacement is not applied to arguments
+    with effects, but with further analysis of the sequence of
+    strict effects within the callee we could relax this constraint.
+
+  - When not all parameters can be substituted by their arguments
+    (e.g. due to possible effects), if the call appears in a
+    statement context, the inliner may introduce a var declaration
+    that declares the parameter variables (with the correct types)
+    and assigns them to their corresponding argument values.
+    The rest of the function body may then follow.
+    For example, the call
+
+    f(1, 2)
+
+    to the function
+
+    func f(x, y int32) { stmts }
+
+    may be reduced to
+
+    { var x, y int32 = 1, 2; stmts }.
+
+    There are many reasons why this is not always possible. For
+    example, true parameters are statically resolved in the same
+    scope, and are dynamically assigned their arguments in
+    parallel; but each spec in a var declaration is statically
+    resolved in sequence and dynamically executed in sequence, so
+    earlier parameters may shadow references in later ones.
+
+  - Even an argument expression as simple as ptr.x may not be
+    referentially transparent, because another argument may have the
+    effect of changing the value of ptr.
+
+    This constraint could be relaxed by some kind of alias or
+    escape analysis that proves that ptr cannot be mutated during
+    the call.
+
+  - Although constants are referentially transparent, as a matter of
+    style we do not wish to duplicate literals that are referenced
+    multiple times in the body because this undoes proper factoring.
+    Also, string literals may be arbitrarily large.
+
+  - If the function body consists of statements other than just
+    "return expr", in some contexts it may be syntactically
+    impossible to reduce the call. Consider:
+
+    if x := f(); cond { ... }
+
+    Go has no equivalent to Lisp's progn or Rust's blocks,
+    nor ML's let expressions (let param = arg in body);
+    its closest equivalent is func(param){body}(arg).
+    Reduction strategies must therefore consider the syntactic
+    context of the call.
+
+    In such situations we could work harder to extract a statement
+    context for the call, by transforming it to:
+
+    { x := f(); if cond { ... } }
+
+  - Similarly, without the equivalent of Rust-style blocks and
+    first-class tuples, there is no general way to reduce a call
+    to a function such as
+
+    func(params)(args)(results) { stmts; return expr }
+
+    to an expression such as
+
+    { var params = args; stmts; expr }
+
+    or even a statement such as
+
+    results = { var params = args; stmts; expr }
+
+    Consequently the declaration and scope of the result variables,
+    and the assignment and control-flow implications of the return
+    statement, must be dealt with by cases.
+
+  - A standalone call statement that calls a function whose body is
+    "return expr" cannot be simply replaced by the body expression
+    if it is not itself a call or channel receive expression; it is
+    necessary to explicitly discard the result using "_ = expr".
+
+    Similarly, if the body is a call expression, only calls to some
+    built-in functions with no result (such as copy or panic) are
+    permitted as statements, whereas others (such as append) return
+    a result that must be used, even if just by discarding.
+
+  - If a parameter or result variable is updated by an assignment
+    within the function body, it cannot always be safely replaced
+    by a variable in the caller. For example, given
+
+    func f(a int) int { a++; return a }
+
+    The call y = f(x) cannot be replaced by { x++; y = x } because
+    this would change the value of the caller's variable x.
+    Only if the caller is finished with x is this safe.
+
+    A similar argument applies to parameter or result variables
+    that escape: by eliminating a variable, inlining would change
+    the identity of the variable that escapes.
+
+  - If the function body uses 'defer' and the inlined call is not a
+    tail-call, inlining may delay the deferred effects.
+
+  - Because the scope of a control label is the entire function, a
+    call cannot be reduced if the caller and callee have intersecting
+    sets of control labels. (It is possible to α-rename any
+    conflicting ones, but our colleagues building C++ refactoring
+    tools report that, when tools must choose new identifiers, they
+    generally do a poor job.)
+
+  - Given
+
+    func f() uint8 { return 0 }
+
+    var x any = f()
+
+    reducing the call to var x any = 0 is unsound because it
+    discards the implicit conversion to uint8. We may need to make
+    each argument-to-parameter conversion explicit if the types
+    differ. Assignments to variadic parameters may need to
+    explicitly construct a slice.
+
+    An analogous problem applies to the implicit assignments in
+    return statements:
+
+    func g() any { return f() }
+
+    Replacing the call f() with 0 would silently lose a
+    conversion to uint8 and change the behavior of the program.
+
+  - When inlining a call f(1, x, g()) where those parameters are
+    unreferenced, we should be able to avoid evaluating 1 and x
+    since they are pure and thus have no effect. But x may be the
+    last reference to a local variable in the caller, so removing
+    it would cause a compilation error. Parameter substitution must
+    avoid making the caller's local variables unreferenced (or must
+    be prepared to eliminate the declaration too---this is where an
+    iterative framework for simplification would really help).
+
+  - An expression such as s[i] may be valid if s and i are
+    variables but invalid if either or both of them are constants.
+    For example, a negative constant index s[-1] is always out of
+    bounds, and even a non-negative constant index may be out of
+    bounds depending on the particular string constant (e.g.
+    "abc"[4]).
+
+    So, if a parameter participates in any expression that is
+    subject to additional compile-time checks when its operands are
+    constant, it may be unsafe to substitute that parameter by a
+    constant argument value (#62664).
+
+More complex callee functions are inlinable with more elaborate and
+invasive changes to the statements surrounding the call expression.
+
+TODO(adonovan): future work:
+
+  - Handle more of the above special cases by careful analysis,
+    thoughtful factoring of the large design space, and thorough
+    test coverage.
+
+  - Compute precisely (not conservatively) when parameter
+    substitution would remove the last reference to a caller local
+    variable, and blank out the local instead of retreating from
+    the substitution.
+
+  - Afford the client more control such as a limit on the total
+    increase in line count, or a refusal to inline using the
+    general approach (replacing name by function literal). This
+    could be achieved by returning metadata alongside the result
+    and having the client conditionally discard the change.
+
+  - Support inlining of generic functions, replacing type parameters
+    by their instantiations.
+
+  - Support inlining of calls to function literals ("closures").
+    But note that the existing algorithm makes widespread assumptions
+    that the callee is a package-level function or method.
+
+  - Eliminate explicit conversions of "untyped" literals inserted
+    conservatively when they are redundant. For example, the
+    conversion int32(1) is redundant when this value is used only as a
+    slice index; but it may be crucial if it is used in x := int32(1)
+    as it changes the type of x, which may have further implications.
+    The conversions may also be important to the falcon analysis.
+
+  - Allow non-'go' build systems such as Bazel/Blaze a chance to
+    decide whether an import is accessible using logic other than
+    "/internal/" path segments. This could be achieved by returning
+    the list of added import paths instead of a text diff.
+
+  - Inlining a function from another module may change the
+    effective version of the Go language spec that governs it. We
+    should probably make the client responsible for rejecting
+    attempts to inline from newer callees to older callers, since
+    there's no way for this package to access module versions.
+
+  - Use an alternative implementation of the import-organizing
+    operation that doesn't require operating on a complete file
+    (and reformatting). Then return the results in a higher-level
+    form as a set of import additions and deletions plus a single
+    diff that encloses the call expression. This interface could
+    perhaps be implemented atop imports.Process by post-processing
+    its result to obtain the abstract import changes and discarding
+    its formatted output.
+*/
+package inline
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/escape.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/escape.go
new file mode 100644
index 00000000000000..45cce11a9e202e
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/escape.go
@@ -0,0 +1,102 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package inline
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+)
+
+// escape implements a simple "address-taken" escape analysis. It
+// calls f for each local variable that appears on the left side of an
+// assignment (escapes=false) or has its address taken (escapes=true).
+// The initialization of a variable by its declaration does not count
+// as an assignment.
+func escape(info *types.Info, root ast.Node, f func(v *types.Var, escapes bool)) {
+
+	// lvalue is called for each address-taken expression or LHS of assignment.
+	// Supported forms are: x, (x), x[i], x.f, *x, T{}.
+	var lvalue func(e ast.Expr, escapes bool)
+	lvalue = func(e ast.Expr, escapes bool) {
+		switch e := e.(type) {
+		case *ast.Ident:
+			if v, ok := info.Uses[e].(*types.Var); ok {
+				if !isPkgLevel(v) {
+					f(v, escapes)
+				}
+			}
+		case *ast.ParenExpr:
+			lvalue(e.X, escapes)
+		case *ast.IndexExpr:
+			// TODO(adonovan): support generics without assuming e.X has a core type.
+			// Consider:
+			//
+			// func Index[T interface{ [3]int | []int }](t T, i int) *int {
+			//     return &t[i]
+			// }
+			//
+			// We must traverse the normal terms and check
+			// whether any of them is an array.
+			//
+			// We assume TypeOf returns non-nil.
+			if _, ok := info.TypeOf(e.X).Underlying().(*types.Array); ok {
+				lvalue(e.X, escapes) // &a[i] on array
+			}
+		case *ast.SelectorExpr:
+			// We assume TypeOf returns non-nil.
+			if _, ok := info.TypeOf(e.X).Underlying().(*types.Struct); ok {
+				lvalue(e.X, escapes) // &s.f on struct
+			}
+		case *ast.StarExpr:
+			// *ptr indirects an existing pointer
+		case *ast.CompositeLit:
+			// &T{...} creates a new variable
+		default:
+			panic(fmt.Sprintf("&x on %T", e)) // unreachable in well-typed code
+		}
+	}
+
+	// Search function body for operations &x, x.f(), x++, and x = y
+	// where x is a parameter. Each of these treats x as an address.
+	ast.Inspect(root, func(n ast.Node) bool {
+		switch n := n.(type) {
+		case *ast.UnaryExpr:
+			if n.Op == token.AND {
+				lvalue(n.X, true) // &x
+			}
+
+		case *ast.CallExpr:
+			// implicit &x in method call x.f(),
+			// where x has type T and method is (*T).f
+			if sel, ok := n.Fun.(*ast.SelectorExpr); ok {
+				if seln, ok := info.Selections[sel]; ok &&
+					seln.Kind() == types.MethodVal &&
+					isPointer(seln.Obj().Type().Underlying().(*types.Signature).Recv().Type()) {
+					tArg, indirect := effectiveReceiver(seln)
+					if !indirect && !isPointer(tArg) {
+						lvalue(sel.X, true) // &x.f
+					}
+				}
+			}
+
+		case *ast.AssignStmt:
+			for _, lhs := range n.Lhs {
+				if id, ok := lhs.(*ast.Ident); ok &&
+					info.Defs[id] != nil &&
+					n.Tok == token.DEFINE {
+					// declaration: doesn't count
+				} else {
+					lvalue(lhs, false)
+				}
+			}
+
+		case *ast.IncDecStmt:
+			lvalue(n.X, false)
+		}
+		return true
+	})
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/falcon.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/falcon.go
new file mode 100644
index 00000000000000..037d33bd5a22ff
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/falcon.go
@@ -0,0 +1,879 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package inline
+
+// This file defines the callee side of the "fallible constant" analysis.
+
+import (
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/format"
+	"go/token"
+	"go/types"
+	"strconv"
+	"strings"
+
+	"golang.org/x/tools/go/types/typeutil"
+	"golang.org/x/tools/internal/typeparams"
+)
+
+// falconResult is the result of the analysis of the callee.
+type falconResult struct {
+	Types       []falconType // types for falcon constraint environment
+	Constraints []string     // constraints (Go expressions) on values of fallible constants
+}
+
+// A falconType specifies the name and underlying type of a synthetic
+// defined type for use in falcon constraints.
+//
+// Unique types from callee code are bijectively mapped onto falcon
+// types so that constraints are independent of callee type
+// information but preserve type equivalence classes.
+//
+// Fresh names are deliberately obscure to avoid shadowing even if a
+// callee parameter has a name like "int" or "any".
+type falconType struct {
+	Name string
+	Kind types.BasicKind // string/number/bool
+}
+
+// falcon identifies "fallible constant" expressions, which are
+// expressions that may fail to compile if one or more of their
+// operands is changed from non-constant to constant.
+//
+// Consider:
+//
+//	func sub(s string, i, j int) string { return s[i:j] }
+//
+// If parameters are replaced by constants, the compiler is
+// required to perform these additional checks:
+//
+//   - if i is constant, 0 <= i.
+//   - if s and i are constant, i <= len(s).
+//   - ditto for j.
+//   - if i and j are constant, i <= j.
+//
+// s[i:j] is thus a "fallible constant" expression dependent on {s, i,
+// j}. Each falcon creates a set of conditional constraints across one
+// or more parameter variables.
+//
+//   - When inlining a call such as sub("abc", -1, 2), the parameter i
+//     cannot be eliminated by substitution as its argument value is
+//     negative.
+//
+//   - When inlining sub("", 2, 1), all three parameters cannot be
+//     simultaneously eliminated by substitution without violating i
+//     <= len(s) and j <= len(s), but the parameters i and j could be
+//     safely eliminated without s.
+//
+// Parameters that cannot be eliminated must remain non-constant,
+// either in the form of a binding declaration:
+//
+//	{ var i int = -1; return "abc"[i:2] }
+//
+// or a parameter of a literalization:
+//
+//	func (i int) string { return "abc"[i:2] }(-1)
+//
+// These example expressions are obviously doomed to fail at run
+// time, but in realistic cases such expressions are dominated by
+// appropriate conditions that make them reachable only when safe:
+//
+//	if 0 <= i && i <= j && j <= len(s) { _ = s[i:j] }
+//
+// (In principle a more sophisticated inliner could entirely eliminate
+// such unreachable blocks based on the condition being always-false
+// for the given parameter substitution, but this is tricky to do safely
+// because the type-checker considers only a single configuration.
+// Consider: if runtime.GOOS == "linux" { ... }.)
+//
+// We believe this is an exhaustive list of "fallible constant" operations:
+//
+//   - switch z { case x: case y } 	// duplicate case values
+//   - s[i], s[i:j], s[i:j:k]		// index out of bounds (0 <= i <= j <= k <= len(s))
+//   - T{x: 0}				// index out of bounds, duplicate index
+//   - x/y, x%y, x/=y, x%=y		// integer division by zero; minint/-1 overflow
+//   - x+y, x-y, x*y			// arithmetic overflow
+//   - x< 1 {
+		var elts []ast.Expr
+		for _, elem := range elems {
+			elts = append(elts, &ast.KeyValueExpr{
+				Key:   elem,
+				Value: makeIntLit(0),
+			})
+		}
+		st.emit(&ast.CompositeLit{
+			Type: typ,
+			Elts: elts,
+		})
+	}
+}
+
+// -- traversal --
+
+// The traversal functions scan the callee body for expressions that
+// are not constant but would become constant if the parameter vars
+// were redeclared as constants, and emits for each one a constraint
+// (a Go expression) with the property that it will not type-check
+// (using types.CheckExpr) if the particular argument values are
+// unsuitable.
+//
+// These constraints are checked by Inline with the actual
+// constant argument values. Violations cause it to reject
+// parameters as candidates for substitution.
+
+func (st *falconState) stmt(s ast.Stmt) {
+	ast.Inspect(s, func(n ast.Node) bool {
+		switch n := n.(type) {
+		case ast.Expr:
+			_ = st.expr(n)
+			return false // skip usual traversal
+
+		case *ast.AssignStmt:
+			switch n.Tok {
+			case token.QUO_ASSIGN, token.REM_ASSIGN:
+				// x /= y
+				// Possible "integer division by zero"
+				// Emit constraint: 1/y.
+				_ = st.expr(n.Lhs[0])
+				kY := st.expr(n.Rhs[0])
+				if kY, ok := kY.(ast.Expr); ok {
+					op := token.QUO
+					if n.Tok == token.REM_ASSIGN {
+						op = token.REM
+					}
+					st.emit(&ast.BinaryExpr{
+						Op: op,
+						X:  makeIntLit(1),
+						Y:  kY,
+					})
+				}
+				return false // skip usual traversal
+			}
+
+		case *ast.SwitchStmt:
+			if n.Init != nil {
+				st.stmt(n.Init)
+			}
+			tBool := types.Type(types.Typ[types.Bool])
+			tagType := tBool // default: true
+			if n.Tag != nil {
+				st.expr(n.Tag)
+				tagType = st.info.TypeOf(n.Tag)
+			}
+
+			// Possible "duplicate case value".
+			// Emit constraint map[T]int{v1: 0, ..., vN:0}
+			// to ensure all maybe-constant case values are unique
+			// (unless switch tag is boolean, which is relaxed).
+			var unique []ast.Expr
+			for _, clause := range n.Body.List {
+				clause := clause.(*ast.CaseClause)
+				for _, caseval := range clause.List {
+					if k := st.expr(caseval); k != nil {
+						unique = append(unique, st.toExpr(k))
+					}
+				}
+				for _, stmt := range clause.Body {
+					st.stmt(stmt)
+				}
+			}
+			if unique != nil && !types.Identical(tagType.Underlying(), tBool) {
+				tname := st.any
+				if !types.IsInterface(tagType) {
+					tname = st.typename(tagType)
+				}
+				t := &ast.MapType{
+					Key:   makeIdent(tname),
+					Value: makeIdent(st.int),
+				}
+				st.emitUnique(t, unique)
+			}
+		}
+		return true
+	})
+}
+
+// fieldTypes visits the .Type of each field in the list.
+func (st *falconState) fieldTypes(fields *ast.FieldList) {
+	if fields != nil {
+		for _, field := range fields.List {
+			_ = st.expr(field.Type)
+		}
+	}
+}
+
+// expr visits the expression (or type) and returns a
+// non-nil result if the expression is constant or would
+// become constant if all suitable function parameters were
+// redeclared as constants.
+//
+// If the expression is constant, st.expr returns its type
+// and value (types.TypeAndValue). If the expression would
+// become constant, st.expr returns an ast.Expr tree whose
+// leaves are literals and parameter references, and whose
+// interior nodes are operations that may become constant,
+// such as -x, x+y, f(x), and T(x). We call these would-be
+// constant expressions "fallible constants", since they may
+// fail to type-check for some values of x, i, and j. (We
+// refer to the non-nil cases collectively as "maybe
+// constant", and the nil case as "definitely non-constant".)
+//
+// As a side effect, st.expr emits constraints for each
+// fallible constant expression; this is its main purpose.
+//
+// Consequently, st.expr must visit the entire subtree so
+// that all necessary constraints are emitted. It may not
+// short-circuit the traversal when it encounters a constant
+// subexpression as constants may contain arbitrary other
+// syntax that may impose constraints. Consider (as always)
+// this contrived but legal example of a type parameter (!)
+// that contains statement syntax:
+//
+//	func f[T [unsafe.Sizeof(func() { stmts })]int]()
+//
+// There is no need to emit constraints for (e.g.) s[i] when s
+// and i are already constants, because we know the expression
+// is sound, but it is sometimes easier to emit these
+// redundant constraints than to avoid them.
+func (st *falconState) expr(e ast.Expr) (res any) { // = types.TypeAndValue | ast.Expr
+	tv := st.info.Types[e]
+	if tv.Value != nil {
+		// A constant value overrides any other result.
+		defer func() { res = tv }()
+	}
+
+	switch e := e.(type) {
+	case *ast.Ident:
+		if v, ok := st.info.Uses[e].(*types.Var); ok {
+			if _, ok := st.params[v]; ok && isBasic(v.Type(), types.IsConstType) {
+				return e // reference to constable parameter
+			}
+		}
+		// (References to *types.Const are handled by the defer.)
+
+	case *ast.BasicLit:
+		// constant
+
+	case *ast.ParenExpr:
+		return st.expr(e.X)
+
+	case *ast.FuncLit:
+		_ = st.expr(e.Type)
+		st.stmt(e.Body)
+		// definitely non-constant
+
+	case *ast.CompositeLit:
+		// T{k: v, ...}, where T ∈ {array,*array,slice,map},
+		// imposes a constraint that all constant k are
+		// distinct and, for arrays [n]T, within range 0-n.
+		//
+		// Types matter, not just values. For example,
+		// an interface-keyed map may contain keys
+		// that are numerically equal so long as they
+		// are of distinct types. For example:
+		//
+		//   type myint int
+		//   map[any]bool{1: true, 1:        true} // error: duplicate key
+		//   map[any]bool{1: true, int16(1): true} // ok
+		//   map[any]bool{1: true, myint(1): true} // ok
+		//
+		// This can be asserted by emitting a
+		// constraint of the form T{k1: 0, ..., kN: 0}.
+		if e.Type != nil {
+			_ = st.expr(e.Type)
+		}
+		t := types.Unalias(typeparams.Deref(tv.Type))
+		ct := typeparams.CoreType(t)
+		var mapKeys []ast.Expr // map key expressions; must be distinct if constant
+		for _, elt := range e.Elts {
+			if kv, ok := elt.(*ast.KeyValueExpr); ok {
+				if is[*types.Map](ct) {
+					if k := st.expr(kv.Key); k != nil {
+						mapKeys = append(mapKeys, st.toExpr(k))
+					}
+				}
+				_ = st.expr(kv.Value)
+			} else {
+				_ = st.expr(elt)
+			}
+		}
+		if len(mapKeys) > 0 {
+			// Inlining a map literal may replace variable key expressions by constants.
+			// All such constants must have distinct values.
+			// (Array and slice literals do not permit non-constant keys.)
+			t := ct.(*types.Map)
+			var typ ast.Expr
+			if types.IsInterface(t.Key()) {
+				typ = &ast.MapType{
+					Key:   makeIdent(st.any),
+					Value: makeIdent(st.int),
+				}
+			} else {
+				typ = &ast.MapType{
+					Key:   makeIdent(st.typename(t.Key())),
+					Value: makeIdent(st.int),
+				}
+			}
+			st.emitUnique(typ, mapKeys)
+		}
+		// definitely non-constant
+
+	case *ast.SelectorExpr:
+		_ = st.expr(e.X)
+		_ = st.expr(e.Sel)
+		// The defer is sufficient to handle
+		// qualified identifiers (pkg.Const).
+		// All other cases are definitely non-constant.
+
+	case *ast.IndexExpr:
+		if tv.IsType() {
+			// type C[T]
+			_ = st.expr(e.X)
+			_ = st.expr(e.Index)
+		} else {
+			// term x[i]
+			//
+			// Constraints (if x is slice/string/array/*array, not map):
+			// - i >= 0
+			//     if i is a fallible constant
+			// - i < len(x)
+			//     if x is array/*array and
+			//     i is a fallible constant;
+			//  or if s is a string and both i,
+			//     s are maybe-constants,
+			//     but not both are constants.
+			kX := st.expr(e.X)
+			kI := st.expr(e.Index)
+			if kI != nil && !is[*types.Map](st.info.TypeOf(e.X).Underlying()) {
+				if kI, ok := kI.(ast.Expr); ok {
+					st.emitNonNegative(kI)
+				}
+				// Emit constraint to check indices against known length.
+				// TODO(adonovan): factor with SliceExpr logic.
+				var x ast.Expr
+				if kX != nil {
+					// string
+					x = st.toExpr(kX)
+				} else if arr, ok := typeparams.CoreType(typeparams.Deref(st.info.TypeOf(e.X))).(*types.Array); ok {
+					// array, *array
+					x = &ast.CompositeLit{
+						Type: &ast.ArrayType{
+							Len: makeIntLit(arr.Len()),
+							Elt: makeIdent(st.int),
+						},
+					}
+				}
+				if x != nil {
+					st.emit(&ast.IndexExpr{
+						X:     x,
+						Index: st.toExpr(kI),
+					})
+				}
+			}
+		}
+		// definitely non-constant
+
+	case *ast.SliceExpr:
+		// x[low:high:max]
+		//
+		// Emit non-negative constraints for each index,
+		// plus low <= high <= max <= len(x)
+		// for each pair that are maybe-constant
+		// but not definitely constant.
+
+		kX := st.expr(e.X)
+		var kLow, kHigh, kMax any
+		if e.Low != nil {
+			kLow = st.expr(e.Low)
+			if kLow != nil {
+				if kLow, ok := kLow.(ast.Expr); ok {
+					st.emitNonNegative(kLow)
+				}
+			}
+		}
+		if e.High != nil {
+			kHigh = st.expr(e.High)
+			if kHigh != nil {
+				if kHigh, ok := kHigh.(ast.Expr); ok {
+					st.emitNonNegative(kHigh)
+				}
+				if kLow != nil {
+					st.emitMonotonic(st.toExpr(kLow), st.toExpr(kHigh))
+				}
+			}
+		}
+		if e.Max != nil {
+			kMax = st.expr(e.Max)
+			if kMax != nil {
+				if kMax, ok := kMax.(ast.Expr); ok {
+					st.emitNonNegative(kMax)
+				}
+				if kHigh != nil {
+					st.emitMonotonic(st.toExpr(kHigh), st.toExpr(kMax))
+				}
+			}
+		}
+
+		// Emit constraint to check indices against known length.
+		var x ast.Expr
+		if kX != nil {
+			// string
+			x = st.toExpr(kX)
+		} else if arr, ok := typeparams.CoreType(typeparams.Deref(st.info.TypeOf(e.X))).(*types.Array); ok {
+			// array, *array
+			x = &ast.CompositeLit{
+				Type: &ast.ArrayType{
+					Len: makeIntLit(arr.Len()),
+					Elt: makeIdent(st.int),
+				},
+			}
+		}
+		if x != nil {
+			// Avoid slice[::max] if kHigh is nonconstant (nil).
+			high, max := st.toExpr(kHigh), st.toExpr(kMax)
+			if high == nil {
+				high = max // => slice[:max:max]
+			}
+			st.emit(&ast.SliceExpr{
+				X:    x,
+				Low:  st.toExpr(kLow),
+				High: high,
+				Max:  max,
+			})
+		}
+		// definitely non-constant
+
+	case *ast.TypeAssertExpr:
+		_ = st.expr(e.X)
+		if e.Type != nil {
+			_ = st.expr(e.Type)
+		}
+
+	case *ast.CallExpr:
+		_ = st.expr(e.Fun)
+		if tv, ok := st.info.Types[e.Fun]; ok && tv.IsType() {
+			// conversion T(x)
+			//
+			// Possible "value out of range".
+			kX := st.expr(e.Args[0])
+			if kX != nil && isBasic(tv.Type, types.IsConstType) {
+				conv := convert(makeIdent(st.typename(tv.Type)), st.toExpr(kX))
+				if is[ast.Expr](kX) {
+					st.emit(conv)
+				}
+				return conv
+			}
+			return nil // definitely non-constant
+		}
+
+		// call f(x)
+
+		all := true // all args are possibly-constant
+		kArgs := make([]ast.Expr, len(e.Args))
+		for i, arg := range e.Args {
+			if kArg := st.expr(arg); kArg != nil {
+				kArgs[i] = st.toExpr(kArg)
+			} else {
+				all = false
+			}
+		}
+
+		// Calls to built-ins with fallibly constant arguments
+		// may become constant. All other calls are either
+		// constant or non-constant
+		if id, ok := e.Fun.(*ast.Ident); ok && all && tv.Value == nil {
+			if builtin, ok := st.info.Uses[id].(*types.Builtin); ok {
+				switch builtin.Name() {
+				case "len", "imag", "real", "complex", "min", "max":
+					return &ast.CallExpr{
+						Fun:      id,
+						Args:     kArgs,
+						Ellipsis: e.Ellipsis,
+					}
+				}
+			}
+		}
+
+	case *ast.StarExpr: // *T, *ptr
+		_ = st.expr(e.X)
+
+	case *ast.UnaryExpr:
+		// + - ! ^ & <- ~
+		//
+		// Possible "negation of minint".
+		// Emit constraint: -x
+		kX := st.expr(e.X)
+		if kX != nil && !is[types.TypeAndValue](kX) {
+			if e.Op == token.SUB {
+				st.emit(&ast.UnaryExpr{
+					Op: e.Op,
+					X:  st.toExpr(kX),
+				})
+			}
+
+			return &ast.UnaryExpr{
+				Op: e.Op,
+				X:  st.toExpr(kX),
+			}
+		}
+
+	case *ast.BinaryExpr:
+		kX := st.expr(e.X)
+		kY := st.expr(e.Y)
+		switch e.Op {
+		case token.QUO, token.REM:
+			// x/y, x%y
+			//
+			// Possible "integer division by zero" or
+			// "minint / -1" overflow.
+			// Emit constraint: x/y or 1/y
+			if kY != nil {
+				if kX == nil {
+					kX = makeIntLit(1)
+				}
+				st.emit(&ast.BinaryExpr{
+					Op: e.Op,
+					X:  st.toExpr(kX),
+					Y:  st.toExpr(kY),
+				})
+			}
+
+		case token.ADD, token.SUB, token.MUL:
+			// x+y, x-y, x*y
+			//
+			// Possible "arithmetic overflow".
+			// Emit constraint: x+y
+			if kX != nil && kY != nil {
+				st.emit(&ast.BinaryExpr{
+					Op: e.Op,
+					X:  st.toExpr(kX),
+					Y:  st.toExpr(kY),
+				})
+			}
+
+		case token.SHL, token.SHR:
+			// x << y, x >> y
+			//
+			// Possible "constant shift too large".
+			// Either operand may be too large individually,
+			// and they may be too large together.
+			// Emit constraint:
+			//    x << y (if both maybe-constant)
+			//    x << 0 (if y is non-constant)
+			//    1 << y (if x is non-constant)
+			if kX != nil || kY != nil {
+				x := st.toExpr(kX)
+				if x == nil {
+					x = makeIntLit(1)
+				}
+				y := st.toExpr(kY)
+				if y == nil {
+					y = makeIntLit(0)
+				}
+				st.emit(&ast.BinaryExpr{
+					Op: e.Op,
+					X:  x,
+					Y:  y,
+				})
+			}
+
+		case token.LSS, token.GTR, token.EQL, token.NEQ, token.LEQ, token.GEQ:
+			// < > == != <= <=
+			//
+			// A "x cmp y" expression with constant operands x, y is
+			// itself constant, but I can't see how a constant bool
+			// could be fallible: the compiler doesn't reject duplicate
+			// boolean cases in a switch, presumably because boolean
+			// switches are less like n-way branches and more like
+			// sequential if-else chains with possibly overlapping
+			// conditions; and there is (sadly) no way to convert a
+			// boolean constant to an int constant.
+		}
+		if kX != nil && kY != nil {
+			return &ast.BinaryExpr{
+				Op: e.Op,
+				X:  st.toExpr(kX),
+				Y:  st.toExpr(kY),
+			}
+		}
+
+	// types
+	//
+	// We need to visit types (and even type parameters)
+	// in order to reach all the places where things could go wrong:
+	//
+	// 	const (
+	// 		s = ""
+	// 		i = 0
+	// 	)
+	// 	type C[T [unsafe.Sizeof(func() { _ = s[i] })]int] bool
+
+	case *ast.IndexListExpr:
+		_ = st.expr(e.X)
+		for _, expr := range e.Indices {
+			_ = st.expr(expr)
+		}
+
+	case *ast.Ellipsis:
+		if e.Elt != nil {
+			_ = st.expr(e.Elt)
+		}
+
+	case *ast.ArrayType:
+		if e.Len != nil {
+			_ = st.expr(e.Len)
+		}
+		_ = st.expr(e.Elt)
+
+	case *ast.StructType:
+		st.fieldTypes(e.Fields)
+
+	case *ast.FuncType:
+		st.fieldTypes(e.TypeParams)
+		st.fieldTypes(e.Params)
+		st.fieldTypes(e.Results)
+
+	case *ast.InterfaceType:
+		st.fieldTypes(e.Methods)
+
+	case *ast.MapType:
+		_ = st.expr(e.Key)
+		_ = st.expr(e.Value)
+
+	case *ast.ChanType:
+		_ = st.expr(e.Value)
+	}
+	return
+}
+
+// toExpr converts the result of visitExpr to a falcon expression.
+// (We don't do this in visitExpr as we first need to discriminate
+// constants from maybe-constants.)
+func (st *falconState) toExpr(x any) ast.Expr {
+	switch x := x.(type) {
+	case nil:
+		return nil
+
+	case types.TypeAndValue:
+		lit := makeLiteral(x.Value)
+		if !isBasic(x.Type, types.IsUntyped) {
+			// convert to "typed" type
+			lit = &ast.CallExpr{
+				Fun:  makeIdent(st.typename(x.Type)),
+				Args: []ast.Expr{lit},
+			}
+		}
+		return lit
+
+	case ast.Expr:
+		return x
+
+	default:
+		panic(x)
+	}
+}
+
+func makeLiteral(v constant.Value) ast.Expr {
+	switch v.Kind() {
+	case constant.Bool:
+		// Rather than refer to the true or false built-ins,
+		// which could be shadowed by poorly chosen parameter
+		// names, we use 0 == 0 for true and 0 != 0 for false.
+		op := token.EQL
+		if !constant.BoolVal(v) {
+			op = token.NEQ
+		}
+		return &ast.BinaryExpr{
+			Op: op,
+			X:  makeIntLit(0),
+			Y:  makeIntLit(0),
+		}
+
+	case constant.String:
+		return &ast.BasicLit{
+			Kind:  token.STRING,
+			Value: v.ExactString(),
+		}
+
+	case constant.Int:
+		return &ast.BasicLit{
+			Kind:  token.INT,
+			Value: v.ExactString(),
+		}
+
+	case constant.Float:
+		return &ast.BasicLit{
+			Kind:  token.FLOAT,
+			Value: v.ExactString(),
+		}
+
+	case constant.Complex:
+		// The components could be float or int.
+		y := makeLiteral(constant.Imag(v))
+		y.(*ast.BasicLit).Value += "i" // ugh
+		if re := constant.Real(v); !consteq(re, kZeroInt) {
+			// complex: x + yi
+			y = &ast.BinaryExpr{
+				Op: token.ADD,
+				X:  makeLiteral(re),
+				Y:  y,
+			}
+		}
+		return y
+
+	default:
+		panic(v.Kind())
+	}
+}
+
+func makeIntLit(x int64) *ast.BasicLit {
+	return &ast.BasicLit{
+		Kind:  token.INT,
+		Value: strconv.FormatInt(x, 10),
+	}
+}
+
+func isBasic(t types.Type, info types.BasicInfo) bool {
+	basic, ok := t.Underlying().(*types.Basic)
+	return ok && basic.Info()&info != 0
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/free.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/free.go
new file mode 100644
index 00000000000000..e3cf313a8a8db4
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/free.go
@@ -0,0 +1,382 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Copied, with considerable changes, from go/parser/resolver.go
+// at af53bd2c03.
+
+package inline
+
+import (
+	"go/ast"
+	"go/token"
+)
+
+// freeishNames computes an approximation to the free names of the AST
+// at node n based solely on syntax, inserting values into the map.
+//
+// In the absence of composite literals, the set of free names is exact. Composite
+// literals introduce an ambiguity that can only be resolved with type information:
+// whether F is a field name or a value in `T{F: ...}`.
+// If includeComplitIdents is true, this function conservatively assumes
+// T is not a struct type, so freeishNames overapproximates: the resulting
+// set may contain spurious entries that are not free lexical references
+// but are references to struct fields.
+// If includeComplitIdents is false, this function assumes that T *is*
+// a struct type, so freeishNames underapproximates: the resulting set
+// may omit names that are free lexical references.
+//
+// The code is based on go/parser.resolveFile, but heavily simplified. Crucial
+// differences are:
+//   - Instead of resolving names to their objects, this function merely records
+//     whether they are free.
+//   - Labels are ignored: they do not refer to values.
+//   - This is never called on FuncDecls or ImportSpecs, so the function
+//     panics if it sees one.
+func freeishNames(free map[string]bool, n ast.Node, includeComplitIdents bool) {
+	v := &freeVisitor{free: free, includeComplitIdents: includeComplitIdents}
+	// Begin with a scope, even though n might not be a form that establishes a scope.
+	// For example, n might be:
+	//    x := ...
+	// Then we need to add the first x to some scope.
+	v.openScope()
+	ast.Walk(v, n)
+	v.closeScope()
+	assert(v.scope == nil, "unbalanced scopes")
+}
+
+// A freeVisitor holds state for a free-name analysis.
+type freeVisitor struct {
+	scope                *scope          // the current innermost scope
+	free                 map[string]bool // free names seen so far
+	includeComplitIdents bool            // include identifier key in composite literals
+}
+
+// scope contains all the names defined in a lexical scope.
+// It is like ast.Scope, but without deprecation warnings.
+type scope struct {
+	names map[string]bool
+	outer *scope
+}
+
+func (s *scope) defined(name string) bool {
+	for ; s != nil; s = s.outer {
+		if s.names[name] {
+			return true
+		}
+	}
+	return false
+}
+
+func (v *freeVisitor) Visit(n ast.Node) ast.Visitor {
+	switch n := n.(type) {
+
+	// Expressions.
+	case *ast.Ident:
+		v.resolve(n)
+
+	case *ast.FuncLit:
+		v.openScope()
+		defer v.closeScope()
+		v.walkFuncType(n.Type)
+		v.walkBody(n.Body)
+
+	case *ast.SelectorExpr:
+		v.walk(n.X)
+		// Skip n.Sel: it cannot be free.
+
+	case *ast.StructType:
+		v.openScope()
+		defer v.closeScope()
+		v.walkFieldList(n.Fields)
+
+	case *ast.FuncType:
+		v.openScope()
+		defer v.closeScope()
+		v.walkFuncType(n)
+
+	case *ast.CompositeLit:
+		v.walk(n.Type)
+		for _, e := range n.Elts {
+			if kv, _ := e.(*ast.KeyValueExpr); kv != nil {
+				if ident, _ := kv.Key.(*ast.Ident); ident != nil {
+					// It is not possible from syntax alone to know whether
+					// an identifier used as a composite literal key is
+					// a struct field (if n.Type is a struct) or a value
+					// (if n.Type is a map, slice or array).
+					if v.includeComplitIdents {
+						// Over-approximate by treating both cases as potentially
+						// free names.
+						v.resolve(ident)
+					} else {
+						// Under-approximate by ignoring potentially free names.
+					}
+				} else {
+					v.walk(kv.Key)
+				}
+				v.walk(kv.Value)
+			} else {
+				v.walk(e)
+			}
+		}
+
+	case *ast.InterfaceType:
+		v.openScope()
+		defer v.closeScope()
+		v.walkFieldList(n.Methods)
+
+	// Statements
+	case *ast.AssignStmt:
+		walkSlice(v, n.Rhs)
+		if n.Tok == token.DEFINE {
+			v.shortVarDecl(n.Lhs)
+		} else {
+			walkSlice(v, n.Lhs)
+		}
+
+	case *ast.LabeledStmt:
+		// ignore labels
+		// TODO(jba): consider labels?
+		v.walk(n.Stmt)
+
+	case *ast.BranchStmt:
+		// Ignore labels.
+		// TODO(jba): consider labels?
+
+	case *ast.BlockStmt:
+		v.openScope()
+		defer v.closeScope()
+		walkSlice(v, n.List)
+
+	case *ast.IfStmt:
+		v.openScope()
+		defer v.closeScope()
+		v.walk(n.Init)
+		v.walk(n.Cond)
+		v.walk(n.Body)
+		v.walk(n.Else)
+
+	case *ast.CaseClause:
+		walkSlice(v, n.List)
+		v.openScope()
+		defer v.closeScope()
+		walkSlice(v, n.Body)
+
+	case *ast.SwitchStmt:
+		v.openScope()
+		defer v.closeScope()
+		v.walk(n.Init)
+		v.walk(n.Tag)
+		v.walkBody(n.Body)
+
+	case *ast.TypeSwitchStmt:
+		if n.Init != nil {
+			v.openScope()
+			defer v.closeScope()
+			v.walk(n.Init)
+		}
+		v.openScope()
+		defer v.closeScope()
+		v.walk(n.Assign)
+		// We can use walkBody here because we don't track label scopes.
+		v.walkBody(n.Body)
+
+	case *ast.CommClause:
+		v.openScope()
+		defer v.closeScope()
+		v.walk(n.Comm)
+		walkSlice(v, n.Body)
+
+	case *ast.SelectStmt:
+		v.walkBody(n.Body)
+
+	case *ast.ForStmt:
+		v.openScope()
+		defer v.closeScope()
+		v.walk(n.Init)
+		v.walk(n.Cond)
+		v.walk(n.Post)
+		v.walk(n.Body)
+
+	case *ast.RangeStmt:
+		v.openScope()
+		defer v.closeScope()
+		v.walk(n.X)
+		var lhs []ast.Expr
+		if n.Key != nil {
+			lhs = append(lhs, n.Key)
+		}
+		if n.Value != nil {
+			lhs = append(lhs, n.Value)
+		}
+		if len(lhs) > 0 {
+			if n.Tok == token.DEFINE {
+				v.shortVarDecl(lhs)
+			} else {
+				walkSlice(v, lhs)
+			}
+		}
+		v.walk(n.Body)
+
+	// Declarations
+	case *ast.GenDecl:
+		switch n.Tok {
+		case token.CONST, token.VAR:
+			for _, spec := range n.Specs {
+				spec := spec.(*ast.ValueSpec)
+				walkSlice(v, spec.Values)
+				if spec.Type != nil {
+					v.walk(spec.Type)
+				}
+				v.declare(spec.Names...)
+			}
+		case token.TYPE:
+			for _, spec := range n.Specs {
+				spec := spec.(*ast.TypeSpec)
+				// Go spec: The scope of a type identifier declared inside a
+				// function begins at the identifier in the TypeSpec and ends
+				// at the end of the innermost containing block.
+				v.declare(spec.Name)
+				if spec.TypeParams != nil {
+					v.openScope()
+					defer v.closeScope()
+					v.walkTypeParams(spec.TypeParams)
+				}
+				v.walk(spec.Type)
+			}
+
+		case token.IMPORT:
+			panic("encountered import declaration in free analysis")
+		}
+
+	case *ast.FuncDecl:
+		panic("encountered top-level function declaration in free analysis")
+
+	default:
+		return v
+	}
+
+	return nil
+}
+
+func (r *freeVisitor) openScope() {
+	r.scope = &scope{map[string]bool{}, r.scope}
+}
+
+func (r *freeVisitor) closeScope() {
+	r.scope = r.scope.outer
+}
+
+func (r *freeVisitor) walk(n ast.Node) {
+	if n != nil {
+		ast.Walk(r, n)
+	}
+}
+
+// walkFuncType walks a function type. It is used for explicit
+// function types, like this:
+//
+//	type RunFunc func(context.Context) error
+//
+// and function literals, like this:
+//
+//	func(a, b int) int { return a + b}
+//
+// neither of which have type parameters.
+// Function declarations do involve type parameters, but we don't
+// handle them.
+func (r *freeVisitor) walkFuncType(typ *ast.FuncType) {
+	// The order here doesn't really matter, because names in
+	// a field list cannot appear in types.
+	// (The situation is different for type parameters, for which
+	// see [freeVisitor.walkTypeParams].)
+	r.resolveFieldList(typ.Params)
+	r.resolveFieldList(typ.Results)
+	r.declareFieldList(typ.Params)
+	r.declareFieldList(typ.Results)
+}
+
+// walkTypeParams is like walkFieldList, but declares type parameters eagerly so
+// that they may be resolved in the constraint expressions held in the field
+// Type.
+func (r *freeVisitor) walkTypeParams(list *ast.FieldList) {
+	r.declareFieldList(list)
+	r.resolveFieldList(list)
+}
+
+func (r *freeVisitor) walkBody(body *ast.BlockStmt) {
+	if body == nil {
+		return
+	}
+	walkSlice(r, body.List)
+}
+
+func (r *freeVisitor) walkFieldList(list *ast.FieldList) {
+	if list == nil {
+		return
+	}
+	r.resolveFieldList(list) // .Type may contain references
+	r.declareFieldList(list) // .Names declares names
+}
+
+func (r *freeVisitor) shortVarDecl(lhs []ast.Expr) {
+	// Go spec: A short variable declaration may redeclare variables provided
+	// they were originally declared in the same block with the same type, and
+	// at least one of the non-blank variables is new.
+	//
+	// However, it doesn't matter to free analysis whether a variable is declared
+	// fresh or redeclared.
+	for _, x := range lhs {
+		// In a well-formed program each expr must be an identifier,
+		// but be forgiving.
+		if id, ok := x.(*ast.Ident); ok {
+			r.declare(id)
+		}
+	}
+}
+
+func walkSlice[S ~[]E, E ast.Node](r *freeVisitor, list S) {
+	for _, e := range list {
+		r.walk(e)
+	}
+}
+
+// resolveFieldList resolves the types of the fields in list.
+// The companion method declareFieldList declares the names of the fields.
+func (r *freeVisitor) resolveFieldList(list *ast.FieldList) {
+	if list == nil {
+		return
+	}
+	for _, f := range list.List {
+		r.walk(f.Type)
+	}
+}
+
+// declareFieldList declares the names of the fields in list.
+// (Names in a FieldList always establish new bindings.)
+// The companion method resolveFieldList resolves the types of the fields.
+func (r *freeVisitor) declareFieldList(list *ast.FieldList) {
+	if list == nil {
+		return
+	}
+	for _, f := range list.List {
+		r.declare(f.Names...)
+	}
+}
+
+// resolve marks ident as free if it is not in scope.
+// TODO(jba): rename: no resolution is happening.
+func (r *freeVisitor) resolve(ident *ast.Ident) {
+	if s := ident.Name; s != "_" && !r.scope.defined(s) {
+		r.free[s] = true
+	}
+}
+
+// declare adds each non-blank ident to the current scope.
+func (r *freeVisitor) declare(idents ...*ast.Ident) {
+	for _, id := range idents {
+		if id.Name != "_" {
+			r.scope.names[id.Name] = true
+		}
+	}
+}
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/inline.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/inline.go
new file mode 100644
index 00000000000000..2443504da7ae54
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/inline.go
@@ -0,0 +1,3744 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package inline
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/constant"
+	"go/format"
+	"go/parser"
+	"go/printer"
+	"go/token"
+	"go/types"
+	"maps"
+	pathpkg "path"
+	"reflect"
+	"slices"
+	"strconv"
+	"strings"
+
+	"golang.org/x/tools/go/ast/astutil"
+	"golang.org/x/tools/go/types/typeutil"
+	internalastutil "golang.org/x/tools/internal/astutil"
+	"golang.org/x/tools/internal/packagepath"
+	"golang.org/x/tools/internal/typeparams"
+	"golang.org/x/tools/internal/typesinternal"
+)
+
+// A Caller describes the function call and its enclosing context.
+//
+// The client is responsible for populating this struct and passing it to Inline.
+type Caller struct {
+	Fset    *token.FileSet
+	Types   *types.Package
+	Info    *types.Info
+	File    *ast.File
+	Call    *ast.CallExpr
+	Content []byte // source of file containing
+
+	path          []ast.Node    // path from call to root of file syntax tree
+	enclosingFunc *ast.FuncDecl // top-level function/method enclosing the call, if any
+}
+
+type logger = func(string, ...any)
+
+// Options specifies parameters affecting the inliner algorithm.
+// All fields are optional.
+type Options struct {
+	Logf          logger // log output function, records decision-making process
+	IgnoreEffects bool   // ignore potential side effects of arguments (unsound)
+}
+
+// Result holds the result of code transformation.
+type Result struct {
+	Content     []byte // formatted, transformed content of caller file
+	Literalized bool   // chosen strategy replaced callee() with func(){...}()
+	BindingDecl bool   // transformation added "var params = args" declaration
+
+	// TODO(adonovan): provide an API for clients that want structured
+	// output: a list of import additions and deletions plus one or more
+	// localized diffs (or even AST transformations, though ownership and
+	// mutation are tricky) near the call site.
+}
+
+// Inline inlines the called function (callee) into the function call (caller)
+// and returns the updated, formatted content of the caller source file.
+//
+// Inline does not mutate any public fields of Caller or Callee.
+func Inline(caller *Caller, callee *Callee, opts *Options) (*Result, error) {
+	copy := *opts // shallow copy
+	opts = ©
+	// Set default options.
+	if opts.Logf == nil {
+		opts.Logf = func(string, ...any) {}
+	}
+
+	st := &state{
+		caller: caller,
+		callee: callee,
+		opts:   opts,
+	}
+	return st.inline()
+}
+
+// state holds the working state of the inliner.
+type state struct {
+	caller *Caller
+	callee *Callee
+	opts   *Options
+}
+
+func (st *state) inline() (*Result, error) {
+	logf, caller, callee := st.opts.Logf, st.caller, st.callee
+
+	logf("inline %s @ %v",
+		debugFormatNode(caller.Fset, caller.Call),
+		caller.Fset.PositionFor(caller.Call.Lparen, false))
+
+	if !consistentOffsets(caller) {
+		return nil, fmt.Errorf("internal error: caller syntax positions are inconsistent with file content (did you forget to use FileSet.PositionFor when computing the file name?)")
+	}
+
+	// Break the string literal so we can use inlining in this file. :)
+	if ast.IsGenerated(caller.File) &&
+		bytes.Contains(caller.Content, []byte("// Code generated by "+"cmd/cgo; DO NOT EDIT.")) {
+		return nil, fmt.Errorf("cannot inline calls from files that import \"C\"")
+	}
+
+	res, err := st.inlineCall()
+	if err != nil {
+		return nil, err
+	}
+
+	// Replace the call (or some node that encloses it) by new syntax.
+	assert(res.old != nil, "old is nil")
+	assert(res.new != nil, "new is nil")
+
+	// A single return operand inlined to a unary
+	// expression context may need parens. Otherwise:
+	//    func two() int { return 1+1 }
+	//    print(-two())  =>  print(-1+1) // oops!
+	//
+	// Usually it is not necessary to insert ParenExprs
+	// as the formatter is smart enough to insert them as
+	// needed by the context. But the res.{old,new}
+	// substitution is done by formatting res.new in isolation
+	// and then splicing its text over res.old, so the
+	// formatter doesn't see the parent node and cannot do
+	// the right thing. (One solution would be to always
+	// format the enclosing node of old, but that requires
+	// non-lossy comment handling, #20744.)
+	//
+	// So, we must analyze the call's context
+	// to see whether ambiguity is possible.
+	// For example, if the context is x[y:z], then
+	// the x subtree is subject to precedence ambiguity
+	// (replacing x by p+q would give p+q[y:z] which is wrong)
+	// but the y and z subtrees are safe.
+	if needsParens(caller.path, res.old, res.new) {
+		res.new = &ast.ParenExpr{X: res.new.(ast.Expr)}
+	}
+
+	// Some reduction strategies return a new block holding the
+	// callee's statements. The block's braces may be elided when
+	// there is no conflict between names declared in the block
+	// with those declared by the parent block, and no risk of
+	// a caller's goto jumping forward across a declaration.
+	//
+	// This elision is only safe when the ExprStmt is beneath a
+	// BlockStmt, CaseClause.Body, or CommClause.Body;
+	// (see "statement theory").
+	//
+	// The inlining analysis may have already determined that eliding braces is
+	// safe. Otherwise, we analyze its safety here.
+	elideBraces := res.elideBraces
+	if !elideBraces {
+		if newBlock, ok := res.new.(*ast.BlockStmt); ok {
+			i := slices.Index(caller.path, res.old)
+			parent := caller.path[i+1]
+			var body []ast.Stmt
+			switch parent := parent.(type) {
+			case *ast.BlockStmt:
+				body = parent.List
+			case *ast.CommClause:
+				body = parent.Body
+			case *ast.CaseClause:
+				body = parent.Body
+			}
+			if body != nil {
+				callerNames := declares(body)
+
+				// If BlockStmt is a function body,
+				// include its receiver, params, and results.
+				addFieldNames := func(fields *ast.FieldList) {
+					if fields != nil {
+						for _, field := range fields.List {
+							for _, id := range field.Names {
+								callerNames[id.Name] = true
+							}
+						}
+					}
+				}
+				switch f := caller.path[i+2].(type) {
+				case *ast.FuncDecl:
+					addFieldNames(f.Recv)
+					addFieldNames(f.Type.Params)
+					addFieldNames(f.Type.Results)
+				case *ast.FuncLit:
+					addFieldNames(f.Type.Params)
+					addFieldNames(f.Type.Results)
+				}
+
+				if len(callerLabels(caller.path)) > 0 {
+					// TODO(adonovan): be more precise and reject
+					// only forward gotos across the inlined block.
+					logf("keeping block braces: caller uses control labels")
+				} else if intersects(declares(newBlock.List), callerNames) {
+					logf("keeping block braces: avoids name conflict")
+				} else {
+					elideBraces = true
+				}
+			}
+		}
+	}
+
+	// File rewriting. This proceeds in multiple passes, in order to maximally
+	// preserve comment positioning. (This could be greatly simplified once
+	// comments are stored in the tree.)
+	//
+	// Don't call replaceNode(caller.File, res.old, res.new)
+	// as it mutates the caller's syntax tree.
+	// Instead, splice the file, replacing the extent of the "old"
+	// node by a formatting of the "new" node, and re-parse.
+	// We'll fix up the imports on this new tree, and format again.
+	//
+	// Inv: f is the result of parsing content, using fset.
+	var (
+		content = caller.Content
+		fset    = caller.Fset
+		f       *ast.File // parsed below
+	)
+	reparse := func() error {
+		const mode = parser.ParseComments | parser.SkipObjectResolution | parser.AllErrors
+		f, err = parser.ParseFile(fset, "callee.go", content, mode)
+		if err != nil {
+			// Something has gone very wrong.
+			logf("failed to reparse <<%s>>: %v", string(content), err) // debugging
+			return err
+		}
+		return nil
+	}
+	{
+		start := offsetOf(fset, res.old.Pos())
+		end := offsetOf(fset, res.old.End())
+		var out bytes.Buffer
+		out.Write(content[:start])
+		// TODO(adonovan): might it make more sense to use
+		// callee.Fset when formatting res.new?
+		// The new tree is a mix of (cloned) caller nodes for
+		// the argument expressions and callee nodes for the
+		// function body. In essence the question is: which
+		// is more likely to have comments?
+		// Usually the callee body will be larger and more
+		// statement-heavy than the arguments, but a
+		// strategy may widen the scope of the replacement
+		// (res.old) from CallExpr to, say, its enclosing
+		// block, so the caller nodes dominate.
+		// Precise comment handling would make this a
+		// non-issue. Formatting wouldn't really need a
+		// FileSet at all.
+		if elideBraces {
+			for i, stmt := range res.new.(*ast.BlockStmt).List {
+				if i > 0 {
+					out.WriteByte('\n')
+				}
+				if err := format.Node(&out, fset, stmt); err != nil {
+					return nil, err
+				}
+			}
+		} else {
+			if err := format.Node(&out, fset, res.new); err != nil {
+				return nil, err
+			}
+		}
+		out.Write(content[end:])
+		content = out.Bytes()
+		if err := reparse(); err != nil {
+			return nil, err
+		}
+	}
+
+	// Add new imports that are still used.
+	newImports := trimNewImports(res.newImports, res.new)
+	// Insert new imports after last existing import,
+	// to avoid migration of pre-import comments.
+	// The imports will be organized below.
+	if len(newImports) > 0 {
+		// If we have imports to add, do so independent of the rest of the file.
+		// Otherwise, the length of the new imports may consume floating comments,
+		// causing them to be printed inside the imports block.
+		var (
+			importDecl    *ast.GenDecl
+			comments      []*ast.CommentGroup // relevant comments.
+			before, after []byte              // pre- and post-amble for the imports block.
+		)
+		if len(f.Imports) > 0 {
+			// Append specs to existing import decl
+			importDecl = f.Decls[0].(*ast.GenDecl)
+			for _, comment := range f.Comments {
+				// Filter comments. Don't use CommentMap.Filter here, because we don't
+				// want to include comments that document the import decl itself, for
+				// example:
+				//
+				//  // We don't want this comment to be duplicated.
+				//  import (
+				//    "something"
+				//  )
+				if importDecl.Pos() <= comment.Pos() && comment.Pos() < importDecl.End() {
+					comments = append(comments, comment)
+				}
+			}
+			before = content[:offsetOf(fset, importDecl.Pos())]
+			importDecl.Doc = nil // present in before
+			after = content[offsetOf(fset, importDecl.End()):]
+		} else {
+			// Insert new import decl.
+			importDecl = &ast.GenDecl{Tok: token.IMPORT}
+			f.Decls = prepend[ast.Decl](importDecl, f.Decls...)
+
+			// Make room for the new declaration after the package declaration.
+			pkgEnd := f.Name.End()
+			file := fset.File(pkgEnd)
+			if file == nil {
+				logf("internal error: missing pkg file")
+				return nil, fmt.Errorf("missing pkg file for %s", f.Name.Name)
+			}
+			// Preserve any comments after the package declaration, by splicing in
+			// the new import block after the end of the package declaration line.
+			line := file.Line(pkgEnd)
+			if line < len(file.Lines()) { // line numbers are 1-based
+				nextLinePos := file.LineStart(line + 1)
+				nextLine := offsetOf(fset, nextLinePos)
+				before = slices.Concat(content[:nextLine], []byte("\n"))
+				after = slices.Concat([]byte("\n\n"), content[nextLine:])
+			} else {
+				before = slices.Concat(content, []byte("\n\n"))
+			}
+		}
+		// Add new imports.
+		// Set their position to after the last position of the old imports, to keep
+		// comments on the old imports from moving.
+		lastPos := token.NoPos
+		if lastSpec := last(importDecl.Specs); lastSpec != nil {
+			lastPos = lastSpec.Pos()
+			if c := lastSpec.(*ast.ImportSpec).Comment; c != nil {
+				lastPos = c.Pos()
+			}
+		}
+		for _, imp := range newImports {
+			// Check that the new imports are accessible.
+			path, _ := strconv.Unquote(imp.spec.Path.Value)
+			if !packagepath.CanImport(caller.Types.Path(), path) {
+				return nil, fmt.Errorf("can't inline function %v as its body refers to inaccessible package %q", callee, path)
+			}
+			if lastPos.IsValid() {
+				lastPos++
+				imp.spec.Path.ValuePos = lastPos
+			}
+			importDecl.Specs = append(importDecl.Specs, imp.spec)
+		}
+
+		var out bytes.Buffer
+		out.Write(before)
+		commented := &printer.CommentedNode{
+			Node:     importDecl,
+			Comments: comments,
+		}
+
+		if err := format.Node(&out, fset, commented); err != nil {
+			logf("failed to format new importDecl: %v", err) // debugging
+			return nil, err
+		}
+		out.Write(after)
+		content = out.Bytes()
+		if err := reparse(); err != nil {
+			return nil, err
+		}
+	}
+	// Delete imports referenced only by caller.Call.Fun.
+	for _, oldImport := range res.oldImports {
+		specToDelete := oldImport.spec
+		name := ""
+		if specToDelete.Name != nil {
+			name = specToDelete.Name.Name
+		}
+		path, _ := strconv.Unquote(specToDelete.Path.Value)
+		astutil.DeleteNamedImport(caller.Fset, f, name, path)
+	}
+
+	var out bytes.Buffer
+	if err := format.Node(&out, caller.Fset, f); err != nil {
+		return nil, err
+	}
+	newSrc := out.Bytes()
+
+	literalized := false
+	if call, ok := res.new.(*ast.CallExpr); ok && is[*ast.FuncLit](call.Fun) {
+		literalized = true
+	}
+
+	return &Result{
+		Content:     newSrc,
+		Literalized: literalized,
+		BindingDecl: res.bindingDecl,
+	}, nil
+}
+
+// An oldImport is an import that will be deleted from the caller file.
+type oldImport struct {
+	pkgName *types.PkgName
+	spec    *ast.ImportSpec
+}
+
+// A newImport is an import that will be added to the caller file.
+type newImport struct {
+	pkgName string
+	spec    *ast.ImportSpec
+}
+
+// importState tracks information about imports.
+type importState struct {
+	logf       func(string, ...any)
+	caller     *Caller
+	importMap  map[string][]string // from package paths in the caller's file to local names
+	newImports []newImport         // for references to free names in callee; to be added to the file
+	oldImports []oldImport         // referenced only by caller.Call.Fun; to be removed from the file
+}
+
+// newImportState returns an importState with initial information about the caller's imports.
+func newImportState(logf func(string, ...any), caller *Caller, callee *gobCallee) *importState {
+	// For simplicity we ignore existing dot imports, so that a qualified
+	// identifier (QI) in the callee is always represented by a QI in the caller,
+	// allowing us to treat a QI like a selection on a package name.
+	is := &importState{
+		logf:      logf,
+		caller:    caller,
+		importMap: make(map[string][]string),
+	}
+
+	for _, imp := range caller.File.Imports {
+		if pkgName, ok := importedPkgName(caller.Info, imp); ok &&
+			pkgName.Name() != "." &&
+			pkgName.Name() != "_" {
+
+			// If the import's sole use is in caller.Call.Fun of the form p.F(...),
+			// where p.F is a qualified identifier, the p import may not be
+			// necessary.
+			//
+			// Only the qualified identifier case matters, as other references to
+			// imported package names in the Call.Fun expression (e.g.
+			// x.after(3*time.Second).f() or time.Second.String()) will remain after
+			// inlining, as arguments.
+			//
+			// If that is the case, proactively check if any of the callee FreeObjs
+			// need this import. Doing so eagerly simplifies the resulting logic.
+			needed := true
+			sel, ok := ast.Unparen(caller.Call.Fun).(*ast.SelectorExpr)
+			if ok && soleUse(caller.Info, pkgName) == sel.X {
+				needed = false // no longer needed by caller
+				// Check to see if any of the inlined free objects need this package.
+				for _, obj := range callee.FreeObjs {
+					if obj.PkgPath == pkgName.Imported().Path() && obj.Shadow[pkgName.Name()] == 0 {
+						needed = true // needed by callee
+						break
+					}
+				}
+			}
+
+			// Exclude imports not needed by the caller or callee after inlining; the second
+			// return value holds these.
+			if needed {
+				path := pkgName.Imported().Path()
+				is.importMap[path] = append(is.importMap[path], pkgName.Name())
+			} else {
+				is.oldImports = append(is.oldImports, oldImport{pkgName: pkgName, spec: imp})
+			}
+		}
+	}
+	return is
+}
+
+// importName finds an existing import name to use in a particular shadowing
+// context. It is used to determine the set of new imports in
+// localName, and is also used for writing out names in inlining
+// strategies below.
+func (i *importState) importName(pkgPath string, shadow shadowMap) string {
+	for _, name := range i.importMap[pkgPath] {
+		// Check that either the import preexisted, or that it was newly added
+		// (no PkgName) but is not shadowed, either in the callee (shadows) or
+		// caller (caller.lookup).
+		if shadow[name] == 0 {
+			found := i.caller.lookup(name)
+			if is[*types.PkgName](found) || found == nil {
+				return name
+			}
+		}
+	}
+	return ""
+}
+
+// localName returns the local name for a given imported package path,
+// adding one if it doesn't exists.
+func (i *importState) localName(pkgPath, pkgName string, shadow shadowMap) string {
+	// Does an import already exist that works in this shadowing context?
+	if name := i.importName(pkgPath, shadow); name != "" {
+		return name
+	}
+
+	newlyAdded := func(name string) bool {
+		return slices.ContainsFunc(i.newImports, func(n newImport) bool { return n.pkgName == name })
+	}
+
+	// shadowedInCaller reports whether a candidate package name
+	// already refers to a declaration in the caller.
+	shadowedInCaller := func(name string) bool {
+		obj := i.caller.lookup(name)
+		if obj == nil {
+			return false
+		}
+		// If obj will be removed, the name is available.
+		return !slices.ContainsFunc(i.oldImports, func(o oldImport) bool { return o.pkgName == obj })
+	}
+
+	// import added by callee
+	//
+	// Choose local PkgName based on last segment of
+	// package path plus, if needed, a numeric suffix to
+	// ensure uniqueness.
+	//
+	// "init" is not a legal PkgName.
+	//
+	// TODO(rfindley): is it worth preserving local package names for callee
+	// imports? Are they likely to be better or worse than the name we choose
+	// here?
+	base := pkgName
+	name := base
+	for n := 0; shadow[name] != 0 || shadowedInCaller(name) || newlyAdded(name) || name == "init"; n++ {
+		name = fmt.Sprintf("%s%d", base, n)
+	}
+	i.logf("adding import %s %q", name, pkgPath)
+	spec := &ast.ImportSpec{
+		Path: &ast.BasicLit{
+			Kind:  token.STRING,
+			Value: strconv.Quote(pkgPath),
+		},
+	}
+	// Use explicit pkgname (out of necessity) when it differs from the declared name,
+	// or (for good style) when it differs from base(pkgpath).
+	if name != pkgName || name != pathpkg.Base(pkgPath) {
+		spec.Name = makeIdent(name)
+	}
+	i.newImports = append(i.newImports, newImport{
+		pkgName: name,
+		spec:    spec,
+	})
+	i.importMap[pkgPath] = append(i.importMap[pkgPath], name)
+	return name
+}
+
+// trimNewImports removes imports that are no longer needed.
+//
+// The list of new imports as constructed by calls to [importState.localName]
+// includes all of the packages referenced by the callee.
+// But in the process of inlining, we may have dropped some of those references.
+// For example, if the callee looked like this:
+//
+//	func F(x int) (p.T) {... /* no mention of p */ ...}
+//
+// and we inlined by assignment:
+//
+//	v := ...
+//
+// then the reference to package p drops away.
+//
+// Remove the excess imports by seeing which remain in new, the expression
+// to be inlined.
+// We can find those by looking at the free names in new.
+// The list of free names cannot include spurious package names.
+// Free-name tracking is precise except for the case of an identifier
+// key in a composite literal, which names either a field or a value.
+// Neither fields nor values are package names.
+// Since they are not relevant to removing unused imports, we instruct
+// freeishNames to omit composite-literal keys that are identifiers.
+func trimNewImports(newImports []newImport, new ast.Node) []newImport {
+	free := map[string]bool{}
+	const omitComplitIdents = false
+	freeishNames(free, new, omitComplitIdents)
+	var res []newImport
+	for _, ni := range newImports {
+		if free[ni.pkgName] {
+			res = append(res, ni)
+		}
+	}
+	return res
+}
+
+type inlineCallResult struct {
+	newImports []newImport // to add
+	oldImports []oldImport // to remove
+
+	// If elideBraces is set, old is an ast.Stmt and new is an ast.BlockStmt to
+	// be spliced in. This allows the inlining analysis to assert that inlining
+	// the block is OK; if elideBraces is unset and old is an ast.Stmt and new is
+	// an ast.BlockStmt, braces may still be elided if the post-processing
+	// analysis determines that it is safe to do so.
+	//
+	// Ideally, it would not be necessary for the inlining analysis to "reach
+	// through" to the post-processing pass in this way. Instead, inlining could
+	// just set old to be an ast.BlockStmt and rewrite the entire BlockStmt, but
+	// unfortunately in order to preserve comments, it is important that inlining
+	// replace as little syntax as possible.
+	elideBraces bool
+	bindingDecl bool     // transformation inserted "var params = args" declaration
+	old, new    ast.Node // e.g. replace call expr by callee function body expression
+}
+
+// inlineCall returns a pair of an old node (the call, or something
+// enclosing it) and a new node (its replacement, which may be a
+// combination of caller, callee, and new nodes), along with the set
+// of new imports needed.
+//
+// TODO(adonovan): rethink the 'result' interface. The assumption of a
+// one-to-one replacement seems fragile. One can easily imagine the
+// transformation replacing the call and adding new variable
+// declarations, for example, or replacing a call statement by zero or
+// many statements.)
+// NOTE(rfindley): we've sort-of done this, with the 'elideBraces' flag that
+// allows inlining a statement list. However, due to loss of comments, more
+// sophisticated rewrites are challenging.
+//
+// TODO(adonovan): in earlier drafts, the transformation was expressed
+// by splicing substrings of the two source files because syntax
+// trees don't preserve comments faithfully (see #20744), but such
+// transformations don't compose. The current implementation is
+// tree-based but is very lossy wrt comments. It would make a good
+// candidate for evaluating an alternative fully self-contained tree
+// representation, such as any proposed solution to #20744, or even
+// dst or some private fork of go/ast.)
+// TODO(rfindley): see if we can reduce the amount of comment lossiness by
+// using printer.CommentedNode, which has been useful elsewhere.
+//
+// TODO(rfindley): inlineCall is getting very long, and very stateful, making
+// it very hard to read. The following refactoring may improve readability and
+// maintainability:
+//   - Rename 'state' to 'callsite', since that is what it encapsulates.
+//   - Add results of pre-processing analysis into the callsite struct, such as
+//     the effective importMap, new/old imports, arguments, etc. Essentially
+//     anything that resulted from initial analysis of the call site, and which
+//     may be useful to inlining strategies.
+//   - Delegate this call site analysis to a constructor or initializer, such
+//     as 'analyzeCallsite', so that it does not consume bandwidth in the
+//     'inlineCall' logical flow.
+//   - Once analyzeCallsite returns, the callsite is immutable, much in the
+//     same way as the Callee and Caller are immutable.
+//   - Decide on a standard interface for strategies (and substrategies), such
+//     that they may be delegated to a separate method on callsite.
+//
+// In this way, the logical flow of inline call will clearly follow the
+// following structure:
+//  1. Analyze the call site.
+//  2. Try strategies, in order, until one succeeds.
+//  3. Process the results.
+//
+// If any expensive analysis may be avoided by earlier strategies, it can be
+// encapsulated in its own type and passed to subsequent strategies.
+func (st *state) inlineCall() (*inlineCallResult, error) {
+	logf, caller, callee := st.opts.Logf, st.caller, &st.callee.impl
+
+	checkInfoFields(caller.Info)
+
+	// Inlining of dynamic calls is not currently supported,
+	// even for local closure calls. (This would be a lot of work.)
+	calleeSymbol := typeutil.StaticCallee(caller.Info, caller.Call)
+	if calleeSymbol == nil {
+		// e.g. interface method
+		return nil, fmt.Errorf("cannot inline: not a static function call")
+	}
+
+	// Reject cross-package inlining if callee has
+	// free references to unexported symbols.
+	samePkg := caller.Types.Path() == callee.PkgPath
+	if !samePkg && len(callee.Unexported) > 0 {
+		return nil, fmt.Errorf("cannot inline call to %s because body refers to non-exported %s",
+			callee.Name, callee.Unexported[0])
+	}
+
+	// -- analyze callee's free references in caller context --
+
+	// Compute syntax path enclosing Call, innermost first (Path[0]=Call),
+	// and outermost enclosing function, if any.
+	caller.path, _ = astutil.PathEnclosingInterval(caller.File, caller.Call.Pos(), caller.Call.End())
+	for _, n := range caller.path {
+		if decl, ok := n.(*ast.FuncDecl); ok {
+			caller.enclosingFunc = decl
+			break
+		}
+	}
+
+	// If call is within a function, analyze all its
+	// local vars for the "single assignment" property.
+	// (Taking the address &v counts as a potential assignment.)
+	var assign1 func(v *types.Var) bool // reports whether v a single-assignment local var
+	{
+		updatedLocals := make(map[*types.Var]bool)
+		if caller.enclosingFunc != nil {
+			escape(caller.Info, caller.enclosingFunc, func(v *types.Var, _ bool) {
+				updatedLocals[v] = true
+			})
+			logf("multiple-assignment vars: %v", updatedLocals)
+		}
+		assign1 = func(v *types.Var) bool { return !updatedLocals[v] }
+	}
+
+	// Extract information about the caller's imports.
+	istate := newImportState(logf, caller, callee)
+
+	// Compute the renaming of the callee's free identifiers.
+	objRenames, err := st.renameFreeObjs(istate)
+	if err != nil {
+		return nil, err
+	}
+
+	res := &inlineCallResult{
+		newImports: istate.newImports,
+		oldImports: istate.oldImports,
+	}
+
+	// Parse callee function declaration.
+	calleeFset, calleeDecl, err := parseCompact(callee.Content)
+	if err != nil {
+		return nil, err // "can't happen"
+	}
+
+	// replaceCalleeID replaces an identifier in the callee. See [replacer] for
+	// more detailed semantics.
+	replaceCalleeID := func(offset int, repl ast.Expr, unpackVariadic bool) {
+		path, id := findIdent(calleeDecl, calleeDecl.Pos()+token.Pos(offset))
+		logf("- replace id %q @ #%d to %q", id.Name, offset, debugFormatNode(calleeFset, repl))
+		// Replace f([]T{a, b, c}...) with f(a, b, c).
+		if lit, ok := repl.(*ast.CompositeLit); ok && unpackVariadic && len(path) > 0 {
+			if call, ok := last(path).(*ast.CallExpr); ok &&
+				call.Ellipsis.IsValid() &&
+				id == last(call.Args) {
+
+				call.Args = append(call.Args[:len(call.Args)-1], lit.Elts...)
+				call.Ellipsis = token.NoPos
+				return
+			}
+		}
+		replaceNode(calleeDecl, id, repl)
+	}
+
+	// Generate replacements for each free identifier.
+	// (The same tree may be spliced in multiple times, resulting in a DAG.)
+	for _, ref := range callee.FreeRefs {
+		if repl := objRenames[ref.Object]; repl != nil {
+			replaceCalleeID(ref.Offset, repl, false)
+		}
+	}
+
+	// Gather the effective call arguments, including the receiver.
+	// Later, elements will be eliminated (=> nil) by parameter substitution.
+	args, err := st.arguments(caller, calleeDecl, assign1)
+	if err != nil {
+		return nil, err // e.g. implicit field selection cannot be made explicit
+	}
+
+	// Gather effective parameter tuple, including the receiver if any.
+	// Simplify variadic parameters to slices (in all cases but one).
+	var params []*parameter // including receiver; nil => parameter substituted
+	{
+		sig := calleeSymbol.Type().(*types.Signature)
+		if sig.Recv() != nil {
+			params = append(params, ¶meter{
+				obj:       sig.Recv(),
+				fieldType: calleeDecl.Recv.List[0].Type,
+				info:      callee.Params[0],
+			})
+		}
+
+		// Flatten the list of syntactic types.
+		var types []ast.Expr
+		for _, field := range calleeDecl.Type.Params.List {
+			if field.Names == nil {
+				types = append(types, field.Type)
+			} else {
+				for range field.Names {
+					types = append(types, field.Type)
+				}
+			}
+		}
+
+		for i := 0; i < sig.Params().Len(); i++ {
+			params = append(params, ¶meter{
+				obj:       sig.Params().At(i),
+				fieldType: types[i],
+				info:      callee.Params[len(params)],
+			})
+		}
+
+		// Variadic function?
+		//
+		// There are three possible types of call:
+		// - ordinary f(a1, ..., aN)
+		// - ellipsis f(a1, ..., slice...)
+		// - spread   f(recv?, g()) where g() is a tuple.
+		// The first two are desugared to non-variadic calls
+		// with an ordinary slice parameter;
+		// the third is tricky and cannot be reduced, and (if
+		// a receiver is present) cannot even be literalized.
+		// Fortunately it is vanishingly rare.
+		//
+		// TODO(adonovan): extract this to a function.
+		if sig.Variadic() {
+			lastParam := last(params)
+			if len(args) > 0 && last(args).spread {
+				// spread call to variadic: tricky
+				lastParam.variadic = true
+			} else {
+				// ordinary/ellipsis call to variadic
+
+				// simplify decl: func(T...) -> func([]T)
+				lastParamField := last(calleeDecl.Type.Params.List)
+				lastParamField.Type = &ast.ArrayType{
+					Elt: lastParamField.Type.(*ast.Ellipsis).Elt,
+				}
+
+				if caller.Call.Ellipsis.IsValid() {
+					// ellipsis call: f(slice...) -> f(slice)
+					// nop
+				} else {
+					// ordinary call: f(a1, ... aN) -> f([]T{a1, ..., aN})
+					//
+					// Substitution of []T{...} in the callee body may lead to
+					// g([]T{a1, ..., aN}...), which we simplify to g(a1, ..., an)
+					// later; see replaceCalleeID.
+					n := len(params) - 1
+					ordinary, extra := args[:n], args[n:]
+					var elts []ast.Expr
+					freevars := make(map[string]bool)
+					pure, effects := true, false
+					for _, arg := range extra {
+						elts = append(elts, arg.expr)
+						pure = pure && arg.pure
+						effects = effects || arg.effects
+						maps.Copy(freevars, arg.freevars)
+					}
+					args = append(ordinary, &argument{
+						expr: &ast.CompositeLit{
+							Type: lastParamField.Type,
+							Elts: elts,
+						},
+						typ:        lastParam.obj.Type(),
+						constant:   nil,
+						pure:       pure,
+						effects:    effects,
+						duplicable: false,
+						freevars:   freevars,
+						variadic:   true,
+					})
+				}
+			}
+		}
+	}
+
+	typeArgs := st.typeArguments(caller.Call)
+	if len(typeArgs) != len(callee.TypeParams) {
+		return nil, fmt.Errorf("cannot inline: type parameter inference is not yet supported")
+	}
+	if err := substituteTypeParams(logf, callee.TypeParams, typeArgs, params, replaceCalleeID); err != nil {
+		return nil, err
+	}
+
+	// Log effective arguments.
+	for i, arg := range args {
+		logf("arg #%d: %s pure=%t effects=%t duplicable=%t free=%v type=%v",
+			i, debugFormatNode(caller.Fset, arg.expr),
+			arg.pure, arg.effects, arg.duplicable, arg.freevars, arg.typ)
+	}
+
+	// Note: computation below should be expressed in terms of
+	// the args and params slices, not the raw material.
+
+	// Perform parameter substitution.
+	// May eliminate some elements of params/args.
+	substitute(logf, caller, params, args, callee.Effects, callee.Falcon, replaceCalleeID)
+
+	// Update the callee's signature syntax.
+	updateCalleeParams(calleeDecl, params)
+
+	// Create a var (param = arg; ...) decl for use by some strategies.
+	bindingDecl := createBindingDecl(logf, caller, args, calleeDecl, callee.Results)
+
+	var remainingArgs []ast.Expr
+	for _, arg := range args {
+		if arg != nil {
+			remainingArgs = append(remainingArgs, arg.expr)
+		}
+	}
+
+	// -- let the inlining strategies begin --
+	//
+	// When we commit to a strategy, we log a message of the form:
+	//
+	//   "strategy: reduce expr-context call to { return expr }"
+	//
+	// This is a terse way of saying:
+	//
+	//    we plan to reduce a call
+	//    that appears in expression context
+	//    to a function whose body is of the form { return expr }
+
+	// TODO(adonovan): split this huge function into a sequence of
+	// function calls with an error sentinel that means "try the
+	// next strategy", and make sure each strategy writes to the
+	// log the reason it didn't match.
+
+	// Special case: eliminate a call to a function whose body is empty.
+	// (=> callee has no results and caller is a statement.)
+	//
+	//    func f(params) {}
+	//    f(args)
+	//    => _, _ = args
+	//
+	if len(calleeDecl.Body.List) == 0 {
+		logf("strategy: reduce call to empty body")
+
+		// Evaluate the arguments for effects and delete the call entirely.
+		// Note(golang/go#71486): stmt can be nil if the call is in a go or defer
+		// statement.
+		// TODO: discard go or defer statements as well.
+		if stmt := callStmt(caller.path, false); stmt != nil {
+			res.old = stmt
+			if nargs := len(remainingArgs); nargs > 0 {
+				// Emit "_, _ = args" to discard results.
+
+				// TODO(adonovan): if args is the []T{a1, ..., an}
+				// literal synthesized during variadic simplification,
+				// consider unwrapping it to its (pure) elements.
+				// Perhaps there's no harm doing this for any slice literal.
+
+				// Make correction for spread calls
+				// f(g()) or recv.f(g()) where g() is a tuple.
+				if last := last(args); last != nil && last.spread {
+					nspread := last.typ.(*types.Tuple).Len()
+					if len(args) > 1 { // [recv, g()]
+						// A single AssignStmt cannot discard both, so use a 2-spec var decl.
+						res.new = &ast.GenDecl{
+							Tok: token.VAR,
+							Specs: []ast.Spec{
+								&ast.ValueSpec{
+									Names:  []*ast.Ident{makeIdent("_")},
+									Values: []ast.Expr{args[0].expr},
+								},
+								&ast.ValueSpec{
+									Names:  blanks[*ast.Ident](nspread),
+									Values: []ast.Expr{args[1].expr},
+								},
+							},
+						}
+						return res, nil
+					}
+
+					// Sole argument is spread call.
+					nargs = nspread
+				}
+
+				res.new = &ast.AssignStmt{
+					Lhs: blanks[ast.Expr](nargs),
+					Tok: token.ASSIGN,
+					Rhs: remainingArgs,
+				}
+
+			} else {
+				// No remaining arguments: delete call statement entirely
+				res.new = &ast.EmptyStmt{}
+			}
+			return res, nil
+		}
+	}
+
+	// If all parameters have been substituted and no result
+	// variable is referenced, we don't need a binding decl.
+	// This may enable better reduction strategies.
+	allResultsUnreferenced := forall(callee.Results, func(i int, r *paramInfo) bool { return len(r.Refs) == 0 })
+	needBindingDecl := !allResultsUnreferenced ||
+		exists(params, func(i int, p *parameter) bool { return p != nil })
+
+	// The two strategies below overlap for a tail call of {return exprs}:
+	// The expr-context reduction is nice because it keeps the
+	// caller's return stmt and merely switches its operand,
+	// without introducing a new block, but it doesn't work with
+	// implicit return conversions.
+	//
+	// TODO(adonovan): unify these cases more cleanly, allowing return-
+	// operand replacement and implicit conversions, by adding
+	// conversions around each return operand (if not a spread return).
+
+	// Special case: call to { return exprs }.
+	//
+	// Reduces to:
+	//	    { var (bindings); _, _ = exprs }
+	//     or   _, _ = exprs
+	//     or   expr
+	//
+	// If:
+	// - the body is just "return expr" with trivial implicit conversions,
+	//   or the caller's return type matches the callee's,
+	// - all parameters and result vars can be eliminated
+	//   or replaced by a binding decl,
+	// then the call expression can be replaced by the
+	// callee's body expression, suitably substituted.
+	if len(calleeDecl.Body.List) == 1 &&
+		is[*ast.ReturnStmt](calleeDecl.Body.List[0]) &&
+		len(calleeDecl.Body.List[0].(*ast.ReturnStmt).Results) > 0 { // not a bare return
+		results := calleeDecl.Body.List[0].(*ast.ReturnStmt).Results
+
+		parent, grandparent := callContext(caller.path)
+
+		// statement context
+		if stmt, ok := parent.(*ast.ExprStmt); ok &&
+			(!needBindingDecl || bindingDecl != nil) {
+			logf("strategy: reduce stmt-context call to { return exprs }")
+			clearPositions(calleeDecl.Body)
+
+			if callee.ValidForCallStmt {
+				logf("callee body is valid as statement")
+				// Inv: len(results) == 1
+				if !needBindingDecl {
+					// Reduces to: expr
+					res.old = caller.Call
+					res.new = results[0]
+				} else {
+					// Reduces to: { var (bindings); expr }
+					res.bindingDecl = true
+					res.old = stmt
+					res.new = &ast.BlockStmt{
+						List: []ast.Stmt{
+							bindingDecl.stmt,
+							&ast.ExprStmt{X: results[0]},
+						},
+					}
+				}
+			} else {
+				logf("callee body is not valid as statement")
+				// The call is a standalone statement, but the
+				// callee body is not suitable as a standalone statement
+				// (f() or <-ch), explicitly discard the results:
+				// Reduces to: _, _ = exprs
+				discard := &ast.AssignStmt{
+					Lhs: blanks[ast.Expr](callee.NumResults),
+					Tok: token.ASSIGN,
+					Rhs: results,
+				}
+				res.old = stmt
+				if !needBindingDecl {
+					// Reduces to: _, _ = exprs
+					res.new = discard
+				} else {
+					// Reduces to: { var (bindings); _, _ = exprs }
+					res.bindingDecl = true
+					res.new = &ast.BlockStmt{
+						List: []ast.Stmt{
+							bindingDecl.stmt,
+							discard,
+						},
+					}
+				}
+			}
+			return res, nil
+		}
+
+		// Assignment context.
+		//
+		// If there is no binding decl, or if the binding decl declares no names,
+		// an assignment a, b := f() can be reduced to a, b := x, y.
+		if stmt, ok := parent.(*ast.AssignStmt); ok &&
+			is[*ast.BlockStmt](grandparent) &&
+			(!needBindingDecl || (bindingDecl != nil && len(bindingDecl.names) == 0)) {
+
+			// Reduces to: { var (bindings); lhs... := rhs... }
+			if newStmts, ok := st.assignStmts(stmt, results, istate.importName); ok {
+				logf("strategy: reduce assign-context call to { return exprs }")
+
+				clearPositions(calleeDecl.Body)
+
+				block := &ast.BlockStmt{
+					List: newStmts,
+				}
+				if needBindingDecl {
+					res.bindingDecl = true
+					block.List = prepend(bindingDecl.stmt, block.List...)
+				}
+
+				// assignStmts does not introduce new bindings, and replacing an
+				// assignment only works if the replacement occurs in the same scope.
+				// Therefore, we must ensure that braces are elided.
+				res.elideBraces = true
+				res.old = stmt
+				res.new = block
+				return res, nil
+			}
+		}
+
+		// expression context
+		if !needBindingDecl {
+			clearPositions(calleeDecl.Body)
+
+			anyNonTrivialReturns := hasNonTrivialReturn(callee.Returns)
+
+			if callee.NumResults == 1 {
+				logf("strategy: reduce expr-context call to { return expr }")
+				// (includes some simple tail-calls)
+
+				// Make implicit return conversion explicit.
+				if anyNonTrivialReturns {
+					results[0] = convert(calleeDecl.Type.Results.List[0].Type, results[0])
+				}
+
+				res.old = caller.Call
+				res.new = results[0]
+				return res, nil
+
+			} else if !anyNonTrivialReturns {
+				logf("strategy: reduce spread-context call to { return expr }")
+				// There is no general way to reify conversions in a spread
+				// return, hence the requirement above.
+				//
+				// TODO(adonovan): allow this reduction when no
+				// conversion is required by the context.
+
+				// The call returns multiple results but is
+				// not a standalone call statement. It must
+				// be the RHS of a spread assignment:
+				//   var x, y  = f()
+				//       x, y := f()
+				//       x, y  = f()
+				// or the sole argument to a spread call:
+				//        printf(f())
+				// or spread return statement:
+				//        return f()
+				res.old = parent
+				switch context := parent.(type) {
+				case *ast.AssignStmt:
+					// Inv: the call must be in Rhs[0], not Lhs.
+					assign := shallowCopy(context)
+					assign.Rhs = results
+					res.new = assign
+				case *ast.ValueSpec:
+					// Inv: the call must be in Values[0], not Names.
+					spec := shallowCopy(context)
+					spec.Values = results
+					res.new = spec
+				case *ast.CallExpr:
+					// Inv: the call must be in Args[0], not Fun.
+					call := shallowCopy(context)
+					call.Args = results
+					res.new = call
+				case *ast.ReturnStmt:
+					// Inv: the call must be Results[0].
+					ret := shallowCopy(context)
+					ret.Results = results
+					res.new = ret
+				default:
+					return nil, fmt.Errorf("internal error: unexpected context %T for spread call", context)
+				}
+				return res, nil
+			}
+		}
+	}
+
+	// Special case: tail-call.
+	//
+	// Inlining:
+	//         return f(args)
+	// where:
+	//         func f(params) (results) { body }
+	// reduces to:
+	//         { var (bindings); body }
+	//         { body }
+	// so long as:
+	// - all parameters can be eliminated or replaced by a binding decl,
+	// - call is a tail-call;
+	// - all returns in body have trivial result conversions,
+	//   or the caller's return type matches the callee's,
+	// - there is no label conflict;
+	// - no result variable is referenced by name,
+	//   or implicitly by a bare return.
+	//
+	// The body may use defer, arbitrary control flow, and
+	// multiple returns.
+	//
+	// TODO(adonovan): add a strategy for a 'void tail
+	// call', i.e. a call statement prior to an (explicit
+	// or implicit) return.
+	parent, _ := callContext(caller.path)
+	if ret, ok := parent.(*ast.ReturnStmt); ok &&
+		len(ret.Results) == 1 &&
+		tailCallSafeReturn(caller, calleeSymbol, callee) &&
+		!callee.HasBareReturn &&
+		(!needBindingDecl || bindingDecl != nil) &&
+		!hasLabelConflict(caller.path, callee.Labels) &&
+		allResultsUnreferenced {
+		logf("strategy: reduce tail-call")
+		body := calleeDecl.Body
+		clearPositions(body)
+		if needBindingDecl {
+			res.bindingDecl = true
+			body.List = prepend(bindingDecl.stmt, body.List...)
+		}
+		res.old = ret
+		res.new = body
+		return res, nil
+	}
+
+	// Special case: call to void function
+	//
+	// Inlining:
+	//         f(args)
+	// where:
+	//	   func f(params) { stmts }
+	// reduces to:
+	//         { var (bindings); stmts }
+	//         { stmts }
+	// so long as:
+	// - callee is a void function (no returns)
+	// - callee does not use defer
+	// - there is no label conflict between caller and callee
+	// - all parameters and result vars can be eliminated
+	//   or replaced by a binding decl,
+	// - caller ExprStmt is in unrestricted statement context.
+	if stmt := callStmt(caller.path, true); stmt != nil &&
+		(!needBindingDecl || bindingDecl != nil) &&
+		!callee.HasDefer &&
+		!hasLabelConflict(caller.path, callee.Labels) &&
+		len(callee.Returns) == 0 {
+		logf("strategy: reduce stmt-context call to { stmts }")
+		body := calleeDecl.Body
+		var repl ast.Stmt = body
+		clearPositions(repl)
+		if needBindingDecl {
+			body.List = prepend(bindingDecl.stmt, body.List...)
+		}
+		res.old = stmt
+		res.new = repl
+		return res, nil
+	}
+
+	// TODO(adonovan): parameterless call to { stmts; return expr }
+	// from one of these contexts:
+	//    x, y     = f()
+	//    x, y    := f()
+	//    var x, y = f()
+	// =>
+	//    var (x T1, y T2); { stmts; x, y = expr }
+	//
+	// Because the params are no longer declared simultaneously
+	// we need to check that (for example) x ∉ freevars(T2),
+	// in addition to the usual checks for arg/result conversions,
+	// complex control, etc.
+	// Also test cases where expr is an n-ary call (spread returns).
+
+	// Literalization isn't quite infallible.
+	// Consider a spread call to a method in which
+	// no parameters are eliminated, e.g.
+	// 	new(T).f(g())
+	// where
+	//  	func (recv *T) f(x, y int) { body }
+	//  	func g() (int, int)
+	// This would be literalized to:
+	// 	func (recv *T, x, y int) { body }(new(T), g()),
+	// which is not a valid argument list because g() must appear alone.
+	// Reject this case for now.
+	if len(args) == 2 && args[0] != nil && args[1] != nil && is[*types.Tuple](args[1].typ) {
+		return nil, fmt.Errorf("can't yet inline spread call to method")
+	}
+
+	// Infallible general case: literalization.
+	//
+	//    func(params) { body }(args)
+	//
+	logf("strategy: literalization")
+	funcLit := &ast.FuncLit{
+		Type: calleeDecl.Type,
+		Body: calleeDecl.Body,
+	}
+	// clear positions before prepending the binding decl below, since the
+	// binding decl contains syntax from the caller and we must not mutate the
+	// caller. (This was a prior bug.)
+	clearPositions(funcLit)
+
+	// Literalization can still make use of a binding
+	// decl as it gives a more natural reading order:
+	//
+	//    func() { var params = args; body }()
+	//
+	// TODO(adonovan): relax the allResultsUnreferenced requirement
+	// by adding a parameter-only (no named results) binding decl.
+	if bindingDecl != nil && allResultsUnreferenced {
+		funcLit.Type.Params.List = nil
+		remainingArgs = nil
+		res.bindingDecl = true
+		funcLit.Body.List = prepend(bindingDecl.stmt, funcLit.Body.List...)
+	}
+
+	// Emit a new call to a function literal in place of
+	// the callee name, with appropriate replacements.
+	newCall := &ast.CallExpr{
+		Fun:      funcLit,
+		Ellipsis: token.NoPos, // f(slice...) is always simplified
+		Args:     remainingArgs,
+	}
+	res.old = caller.Call
+	res.new = newCall
+	return res, nil
+}
+
+// renameFreeObjs computes the renaming of the callee's free identifiers.
+// It returns a slice of names (identifiers or selector expressions) corresponding
+// to the callee's free objects (gobCallee.FreeObjs).
+func (st *state) renameFreeObjs(istate *importState) ([]ast.Expr, error) {
+	caller, callee := st.caller, &st.callee.impl
+	objRenames := make([]ast.Expr, len(callee.FreeObjs)) // nil => no change
+	for i, obj := range callee.FreeObjs {
+		// obj is a free object of the callee.
+		//
+		// Possible cases are:
+		// - builtin function, type, or value (e.g. nil, zero)
+		//   => check not shadowed in caller.
+		// - package-level var/func/const/types
+		//   => same package: check not shadowed in caller.
+		//   => otherwise: import other package, form a qualified identifier.
+		//      (Unexported cross-package references were rejected already.)
+		// - type parameter
+		//   => not yet supported
+		// - pkgname
+		//   => import other package and use its local name.
+		//
+		// There can be no free references to labels, fields, or methods.
+
+		// Note that we must consider potential shadowing both
+		// at the caller side (caller.lookup) and, when
+		// choosing new PkgNames, within the callee (obj.shadow).
+
+		var newName ast.Expr
+		if obj.Kind == "pkgname" {
+			// Use locally appropriate import, creating as needed.
+			n := istate.localName(obj.PkgPath, obj.PkgName, obj.Shadow)
+			newName = makeIdent(n) // imported package
+		} else if !obj.ValidPos {
+			// Built-in function, type, or value (e.g. nil, zero):
+			// check not shadowed at caller.
+			found := caller.lookup(obj.Name) // always finds something
+			if found.Pos().IsValid() {
+				return nil, fmt.Errorf("cannot inline, because the callee refers to built-in %q, which in the caller is shadowed by a %s (declared at line %d)",
+					obj.Name, objectKind(found),
+					caller.Fset.PositionFor(found.Pos(), false).Line)
+			}
+
+		} else {
+			// Must be reference to package-level var/func/const/type,
+			// since type parameters are not yet supported.
+			qualify := false
+			if obj.PkgPath == callee.PkgPath {
+				// reference within callee package
+				if caller.Types.Path() == callee.PkgPath {
+					// Caller and callee are in same package.
+					// Check caller has not shadowed the decl.
+					//
+					// This may fail if the callee is "fake", such as for signature
+					// refactoring where the callee is modified to be a trivial wrapper
+					// around the refactored signature.
+					found := caller.lookup(obj.Name)
+					if found != nil && !isPkgLevel(found) {
+						return nil, fmt.Errorf("cannot inline, because the callee refers to %s %q, which in the caller is shadowed by a %s (declared at line %d)",
+							obj.Kind, obj.Name,
+							objectKind(found),
+							caller.Fset.PositionFor(found.Pos(), false).Line)
+					}
+				} else {
+					// Cross-package reference.
+					qualify = true
+				}
+			} else {
+				// Reference to a package-level declaration
+				// in another package, without a qualified identifier:
+				// it must be a dot import.
+				qualify = true
+			}
+
+			// Form a qualified identifier, pkg.Name.
+			if qualify {
+				pkgName := istate.localName(obj.PkgPath, obj.PkgName, obj.Shadow)
+				newName = &ast.SelectorExpr{
+					X:   makeIdent(pkgName),
+					Sel: makeIdent(obj.Name),
+				}
+			}
+		}
+		objRenames[i] = newName
+	}
+	return objRenames, nil
+}
+
+type argument struct {
+	expr          ast.Expr
+	typ           types.Type      // may be tuple for sole non-receiver arg in spread call
+	constant      constant.Value  // value of argument if constant
+	spread        bool            // final arg is call() assigned to multiple params
+	pure          bool            // expr is pure (doesn't read variables)
+	effects       bool            // expr has effects (updates variables)
+	duplicable    bool            // expr may be duplicated
+	freevars      map[string]bool // free names of expr
+	variadic      bool            // is explicit []T{...} for eliminated variadic
+	desugaredRecv bool            // is *recv or &recv, where operator was elided
+}
+
+// typeArguments returns the type arguments of the call.
+// It only collects the arguments that are explicitly provided; it does
+// not attempt type inference.
+func (st *state) typeArguments(call *ast.CallExpr) []*argument {
+	var exprs []ast.Expr
+	switch d := ast.Unparen(call.Fun).(type) {
+	case *ast.IndexExpr:
+		exprs = []ast.Expr{d.Index}
+	case *ast.IndexListExpr:
+		exprs = d.Indices
+	default:
+		// No type  arguments
+		return nil
+	}
+	var args []*argument
+	for _, e := range exprs {
+		arg := &argument{expr: e, freevars: freeVars(st.caller.Info, e)}
+		// Wrap the instantiating type in parens when it's not an
+		// ident or qualified ident to prevent "if x == struct{}"
+		// parsing ambiguity, or "T(x)" where T = "*int" or "func()"
+		// from misparsing.
+		// TODO(adonovan): this fails in cases where parens are disallowed, such as
+		// in the composite literal expression T{k: v}.
+		if _, ok := arg.expr.(*ast.Ident); !ok {
+			arg.expr = &ast.ParenExpr{X: arg.expr}
+		}
+		args = append(args, arg)
+	}
+	return args
+}
+
+// arguments returns the effective arguments of the call.
+//
+// If the receiver argument and parameter have
+// different pointerness, make the "&" or "*" explicit.
+//
+// Also, if x.f() is shorthand for promoted method x.y.f(),
+// make the .y explicit in T.f(x.y, ...).
+//
+// Beware that:
+//
+//   - a method can only be called through a selection, but only
+//     the first of these two forms needs special treatment:
+//
+//     expr.f(args)     -> ([&*]expr, args)	MethodVal
+//     T.f(recv, args)  -> (    expr, args)	MethodExpr
+//
+//   - the presence of a value in receiver-position in the call
+//     is a property of the caller, not the callee. A method
+//     (calleeDecl.Recv != nil) may be called like an ordinary
+//     function.
+//
+//   - the types.Signatures seen by the caller (from
+//     StaticCallee) and by the callee (from decl type)
+//     differ in this case.
+//
+// In a spread call f(g()), the sole ordinary argument g(),
+// always last in args, has a tuple type.
+//
+// We compute type-based predicates like pure, duplicable,
+// freevars, etc, now, before we start modifying syntax.
+func (st *state) arguments(caller *Caller, calleeDecl *ast.FuncDecl, assign1 func(*types.Var) bool) ([]*argument, error) {
+	var args []*argument
+
+	callArgs := caller.Call.Args
+	if calleeDecl.Recv != nil {
+		if len(st.callee.impl.TypeParams) > 0 {
+			return nil, fmt.Errorf("cannot inline: generic methods not yet supported")
+		}
+		sel := ast.Unparen(caller.Call.Fun).(*ast.SelectorExpr)
+		seln := caller.Info.Selections[sel]
+		var recvArg ast.Expr
+		switch seln.Kind() {
+		case types.MethodVal: // recv.f(callArgs)
+			recvArg = sel.X
+		case types.MethodExpr: // T.f(recv, callArgs)
+			recvArg = callArgs[0]
+			callArgs = callArgs[1:]
+		}
+		if recvArg != nil {
+			// Compute all the type-based predicates now,
+			// before we start meddling with the syntax;
+			// the meddling will update them.
+			arg := &argument{
+				expr:       recvArg,
+				typ:        caller.Info.TypeOf(recvArg),
+				constant:   caller.Info.Types[recvArg].Value,
+				pure:       pure(caller.Info, assign1, recvArg),
+				effects:    st.effects(caller.Info, recvArg),
+				duplicable: duplicable(caller.Info, recvArg),
+				freevars:   freeVars(caller.Info, recvArg),
+			}
+			recvArg = nil // prevent accidental use
+
+			// Move receiver argument recv.f(args) to argument list f(&recv, args).
+			args = append(args, arg)
+
+			// Make field selections explicit (recv.f -> recv.y.f),
+			// updating arg.{expr,typ}.
+			indices := seln.Index()
+			for _, index := range indices[:len(indices)-1] {
+				fld := typeparams.CoreType(typeparams.Deref(arg.typ)).(*types.Struct).Field(index)
+				if fld.Pkg() != caller.Types && !fld.Exported() {
+					return nil, fmt.Errorf("in %s, implicit reference to unexported field .%s cannot be made explicit",
+						debugFormatNode(caller.Fset, caller.Call.Fun),
+						fld.Name())
+				}
+				if isPointer(arg.typ) {
+					arg.pure = false // implicit *ptr operation => impure
+				}
+				arg.expr = &ast.SelectorExpr{
+					X:   arg.expr,
+					Sel: makeIdent(fld.Name()),
+				}
+				arg.typ = fld.Type()
+				arg.duplicable = false
+			}
+
+			// Make * or & explicit.
+			argIsPtr := isPointer(arg.typ)
+			paramIsPtr := isPointer(seln.Obj().Type().Underlying().(*types.Signature).Recv().Type())
+			if !argIsPtr && paramIsPtr {
+				// &recv
+				arg.expr = &ast.UnaryExpr{Op: token.AND, X: arg.expr}
+				arg.typ = types.NewPointer(arg.typ)
+				arg.desugaredRecv = true
+			} else if argIsPtr && !paramIsPtr {
+				// *recv
+				arg.expr = &ast.StarExpr{X: arg.expr}
+				arg.typ = typeparams.Deref(arg.typ)
+				arg.duplicable = false
+				arg.pure = false
+				arg.desugaredRecv = true
+			}
+		}
+	}
+	for _, expr := range callArgs {
+		tv := caller.Info.Types[expr]
+		args = append(args, &argument{
+			expr:       expr,
+			typ:        tv.Type,
+			constant:   tv.Value,
+			spread:     is[*types.Tuple](tv.Type), // => last
+			pure:       pure(caller.Info, assign1, expr),
+			effects:    st.effects(caller.Info, expr),
+			duplicable: duplicable(caller.Info, expr),
+			freevars:   freeVars(caller.Info, expr),
+		})
+	}
+
+	// Re-typecheck each constant argument expression in a neutral context.
+	//
+	// In a call such as func(int16){}(1), the type checker infers
+	// the type "int16", not "untyped int", for the argument 1,
+	// because it has incorporated information from the left-hand
+	// side of the assignment implicit in parameter passing, but
+	// of course in a different context, the expression 1 may have
+	// a different type.
+	//
+	// So, we must use CheckExpr to recompute the type of the
+	// argument in a neutral context to find its inherent type.
+	// (This is arguably a bug in go/types, but I'm pretty certain
+	// I requested it be this way long ago... -adonovan)
+	//
+	// This is only needed for constants. Other implicit
+	// assignment conversions, such as unnamed-to-named struct or
+	// chan to <-chan, do not result in the type-checker imposing
+	// the LHS type on the RHS value.
+	for _, arg := range args {
+		if arg.constant == nil {
+			continue
+		}
+		info := &types.Info{Types: make(map[ast.Expr]types.TypeAndValue)}
+		if err := types.CheckExpr(caller.Fset, caller.Types, caller.Call.Pos(), arg.expr, info); err != nil {
+			return nil, err
+		}
+		arg.typ = info.TypeOf(arg.expr)
+	}
+
+	return args, nil
+}
+
+type parameter struct {
+	obj       *types.Var // parameter var from caller's signature
+	fieldType ast.Expr   // syntax of type, from calleeDecl.Type.{Recv,Params}
+	info      *paramInfo // information from AnalyzeCallee
+	variadic  bool       // (final) parameter is unsimplified ...T
+}
+
+// A replacer replaces an identifier at the given offset in the callee.
+// The replacement tree must not belong to the caller; use cloneNode as needed.
+// If unpackVariadic is set, the replacement is a composite resulting from
+// variadic elimination, and may be unpacked into variadic calls.
+type replacer = func(offset int, repl ast.Expr, unpackVariadic bool)
+
+// substituteTypeParams replaces type parameters in the callee with the corresponding type arguments
+// from the call.
+func substituteTypeParams(logf logger, typeParams []*paramInfo, typeArgs []*argument, params []*parameter, replace replacer) error {
+	assert(len(typeParams) == len(typeArgs), "mismatched number of type params/args")
+	for i, paramInfo := range typeParams {
+		arg := typeArgs[i]
+		// Perform a simplified, conservative shadow analysis: fail if there is any shadowing.
+		for free := range arg.freevars {
+			if paramInfo.Shadow[free] != 0 {
+				return fmt.Errorf("cannot inline: type argument #%d (type parameter %s) is shadowed", i, paramInfo.Name)
+			}
+		}
+		logf("replacing type param %s with %s", paramInfo.Name, debugFormatNode(token.NewFileSet(), arg.expr))
+		for _, ref := range paramInfo.Refs {
+			replace(ref.Offset, internalastutil.CloneNode(arg.expr), false)
+		}
+		// Also replace parameter field types.
+		// TODO(jba): find a way to do this that is not so slow and clumsy.
+		// Ideally, we'd walk each p.fieldType once, replacing all type params together.
+		for _, p := range params {
+			if id, ok := p.fieldType.(*ast.Ident); ok && id.Name == paramInfo.Name {
+				p.fieldType = arg.expr
+			} else {
+				for _, id := range identsNamed(p.fieldType, paramInfo.Name) {
+					replaceNode(p.fieldType, id, arg.expr)
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func identsNamed(n ast.Node, name string) []*ast.Ident {
+	var ids []*ast.Ident
+	ast.Inspect(n, func(n ast.Node) bool {
+		if id, ok := n.(*ast.Ident); ok && id.Name == name {
+			ids = append(ids, id)
+		}
+		return true
+	})
+	return ids
+}
+
+// substitute implements parameter elimination by substitution.
+//
+// It considers each parameter and its corresponding argument in turn
+// and evaluate these conditions:
+//
+//   - the parameter is neither address-taken nor assigned;
+//   - the argument is pure;
+//   - if the parameter refcount is zero, the argument must
+//     not contain the last use of a local var;
+//   - if the parameter refcount is > 1, the argument must be duplicable;
+//   - the argument (or types.Default(argument) if it's untyped) has
+//     the same type as the parameter.
+//
+// If all conditions are met then the parameter can be substituted and
+// each reference to it replaced by the argument. In that case, the
+// replaceCalleeID function is called for each reference to the
+// parameter, and is provided with its relative offset and replacement
+// expression (argument), and the corresponding elements of params and
+// args are replaced by nil.
+func substitute(logf logger, caller *Caller, params []*parameter, args []*argument, effects []int, falcon falconResult, replace replacer) {
+	// Inv:
+	//  in        calls to     variadic, len(args) >= len(params)-1
+	//  in spread calls to non-variadic, len(args) <  len(params)
+	//  in spread calls to     variadic, len(args) <= len(params)
+	// (In spread calls len(args) = 1, or 2 if call has receiver.)
+	// Non-spread variadics have been simplified away already,
+	// so the args[i] lookup is safe if we stop after the spread arg.
+	assert(len(args) <= len(params), "too many arguments")
+
+	// Collect candidates for substitution.
+	//
+	// An argument is a candidate if it is not otherwise rejected, and any free
+	// variables that are shadowed only by other parameters.
+	//
+	// Therefore, substitution candidates are represented by a graph, where edges
+	// lead from each argument to the other arguments that, if substituted, would
+	// allow the argument to be substituted. We collect these edges in the
+	// [substGraph]. Any node that is known not to be elided from the graph.
+	// Arguments in this graph with no edges are substitutable independent of
+	// other nodes, though they may be removed due to falcon or effects analysis.
+	sg := make(substGraph)
+next:
+	for i, param := range params {
+		arg := args[i]
+
+		// Check argument against parameter.
+		//
+		// Beware: don't use types.Info on arg since
+		// the syntax may be synthetic (not created by parser)
+		// and thus lacking positions and types;
+		// do it earlier (see pure/duplicable/freevars).
+
+		if arg.spread {
+			// spread => last argument, but not always last parameter
+			logf("keeping param %q and following ones: argument %s is spread",
+				param.info.Name, debugFormatNode(caller.Fset, arg.expr))
+			return // give up
+		}
+		assert(!param.variadic, "unsimplified variadic parameter")
+		if param.info.Escapes {
+			logf("keeping param %q: escapes from callee", param.info.Name)
+			continue
+		}
+		if param.info.Assigned {
+			logf("keeping param %q: assigned by callee", param.info.Name)
+			continue // callee needs the parameter variable
+		}
+		if len(param.info.Refs) > 1 && !arg.duplicable {
+			logf("keeping param %q: argument is not duplicable", param.info.Name)
+			continue // incorrect or poor style to duplicate an expression
+		}
+		if len(param.info.Refs) == 0 {
+			if arg.effects {
+				logf("keeping param %q: though unreferenced, it has effects", param.info.Name)
+				continue
+			}
+
+			// If the caller is within a function body,
+			// eliminating an unreferenced parameter might
+			// remove the last reference to a caller local var.
+			if caller.enclosingFunc != nil {
+				for free := range arg.freevars {
+					// TODO(rfindley): we can get this 100% right by looking for
+					// references among other arguments which have non-zero references
+					// within the callee.
+					if v, ok := caller.lookup(free).(*types.Var); ok && within(v.Pos(), caller.enclosingFunc.Body) && !isUsedOutsideCall(caller, v) {
+
+						// Check to see if the substituted var is used within other args
+						// whose corresponding params ARE used in the callee
+						usedElsewhere := func() bool {
+							for i, param := range params {
+								if i < len(args) && len(param.info.Refs) > 0 { // excludes original param
+									for name := range args[i].freevars {
+										if caller.lookup(name) == v {
+											return true
+										}
+									}
+								}
+							}
+							return false
+						}
+						if !usedElsewhere() {
+							logf("keeping param %q: arg contains perhaps the last reference to caller local %v @ %v",
+								param.info.Name, v, caller.Fset.PositionFor(v.Pos(), false))
+							continue next
+						}
+					}
+				}
+			}
+		}
+
+		// Arg is a potential substitution candidate: analyze its shadowing.
+		//
+		// Consider inlining a call f(z, 1) to
+		//
+		// 	func f(x, y int) int { z := y; return x + y + z }
+		//
+		// we can't replace x in the body by z (or any
+		// expression that has z as a free identifier) because there's an
+		// intervening declaration of z that would shadow the caller's one.
+		//
+		// However, we *could* replace x in the body by y, as long as the y
+		// parameter is also removed by substitution.
+
+		sg[arg] = nil // Absent shadowing, the arg is substitutable.
+		for free := range arg.freevars {
+			switch s := param.info.Shadow[free]; {
+			case s < 0:
+				// Shadowed by a non-parameter symbol, so arg is not substitutable.
+				delete(sg, arg)
+			case s > 0:
+				// Shadowed by a parameter; arg may be substitutable, if only shadowed
+				// by other substitutable parameters.
+				if s > len(args) {
+					// Defensive: this should not happen in the current factoring, since
+					// spread arguments are already handled.
+					delete(sg, arg)
+				}
+				if edges, ok := sg[arg]; ok {
+					sg[arg] = append(edges, args[s-1])
+				}
+			}
+		}
+	}
+
+	// Process the initial state of the substitution graph.
+	sg.prune()
+
+	// Now we check various conditions on the substituted argument set as a
+	// whole. These conditions reject substitution candidates, but since their
+	// analysis depends on the full set of candidates, we do not process side
+	// effects of their candidate rejection until after the analysis completes,
+	// in a call to prune. After pruning, we must re-run the analysis to check
+	// for additional rejections.
+	//
+	// Here's an example of that in practice:
+	//
+	// 	var a [3]int
+	//
+	// 	func falcon(x, y, z int) {
+	// 		_ = x + a[y+z]
+	// 	}
+	//
+	// 	func _() {
+	// 		var y int
+	// 		const x, z = 1, 2
+	// 		falcon(y, x, z)
+	// 	}
+	//
+	// In this example, arguments 0 and 1 are shadowed by each other's
+	// corresponding parameter, and so each can be substituted only if they are
+	// both substituted. But the fallible constant analysis finds a violated
+	// constraint: x + z = 3, and so the constant array index would cause a
+	// compile-time error if argument 1 (x) were substituted. Therefore,
+	// following the falcon analysis, we must also prune argument 0.
+	//
+	// As far as I (rfindley) can tell, the falcon analysis should always succeed
+	// after the first pass, as it's not possible for additional bindings to
+	// cause new constraint failures. Nevertheless, we re-run it to be sure.
+	//
+	// However, the same cannot be said of the effects analysis, as demonstrated
+	// by this example:
+	//
+	// 	func effects(w, x, y, z int) {
+	// 		_ = x + w + y + z
+	// 	}
+
+	// 	func _() {
+	// 		v := 0
+	// 		w := func() int { v++; return 0 }
+	// 		x := func() int { v++; return 0 }
+	// 		y := func() int { v++; return 0 }
+	// 		effects(x(), w(), y(), x()) //@ inline(re"effects", effects)
+	// 	}
+	//
+	// In this example, arguments 0, 1, and 3 are related by the substitution
+	// graph. The first effects analysis implies that arguments 0 and 1 must be
+	// bound, and therefore argument 3 must be bound. But then a subsequent
+	// effects analysis forces argument 2 to also be bound.
+
+	// Reject constant arguments as substitution candidates if they cause
+	// violation of falcon constraints.
+	//
+	// Keep redoing the analysis until we no longer reject additional arguments,
+	// as the set of substituted parameters affects the falcon package.
+	for checkFalconConstraints(logf, params, args, falcon, sg) {
+		sg.prune()
+	}
+
+	// As a final step, introduce bindings to resolve any
+	// evaluation order hazards. This must be done last, as
+	// additional subsequent bindings could introduce new hazards.
+	//
+	// As with the falcon analysis, keep redoing the analysis until the no more
+	// arguments are rejected.
+	for resolveEffects(logf, args, effects, sg) {
+		sg.prune()
+	}
+
+	// The remaining candidates are safe to substitute.
+	for i, param := range params {
+		if arg := args[i]; sg.has(arg) {
+
+			// It is safe to substitute param and replace it with arg.
+			// The formatter introduces parens as needed for precedence.
+			//
+			// Because arg.expr belongs to the caller,
+			// we clone it before splicing it into the callee tree.
+			logf("replacing parameter %q by argument %q",
+				param.info.Name, debugFormatNode(caller.Fset, arg.expr))
+			for _, ref := range param.info.Refs {
+				// Apply any transformations necessary for this reference.
+				argExpr := arg.expr
+
+				// If the reference itself is being selected, and we applied desugaring
+				// (an explicit &x or *x), we can undo that desugaring here as it is
+				// not necessary for a selector. We don't need to check addressability
+				// here because if we desugared, the receiver must have been
+				// addressable.
+				if ref.IsSelectionOperand && arg.desugaredRecv {
+					switch e := argExpr.(type) {
+					case *ast.UnaryExpr:
+						argExpr = e.X
+					case *ast.StarExpr:
+						argExpr = e.X
+					}
+				}
+
+				// If the reference requires exact type agreement between parameter and
+				// argument, wrap the argument in an explicit conversion if
+				// substitution might materially change its type. (We already did the
+				// necessary shadowing check on the parameter type syntax.)
+				//
+				// The types must agree in any of these cases:
+				// - the argument affects type inference;
+				// - the reference's concrete type is assigned to an interface type;
+				// - the reference is not an assignment, nor a trivial conversion of an untyped constant.
+				//
+				// In all other cases, no explicit conversion is necessary as either
+				// the type does not matter, or must have already agreed for well-typed
+				// code.
+				//
+				// This is only needed for substituted arguments. All other arguments
+				// are given explicit types in either a binding decl or when using the
+				// literalization strategy.
+				//
+				// If the types are identical, we can eliminate
+				// redundant type conversions such as this:
+				//
+				// Callee:
+				//    func f(i int32) { fmt.Println(i) }
+				// Caller:
+				//    func g() { f(int32(1)) }
+				// Inlined as:
+				//    func g() { fmt.Println(int32(int32(1)))
+				//
+				// Recall that non-trivial does not imply non-identical for constant
+				// conversions; however, at this point state.arguments has already
+				// re-typechecked the constant and set arg.type to its (possibly
+				// "untyped") inherent type, so the conversion from untyped 1 to int32
+				// is non-trivial even though both arg and param have identical types
+				// (int32).
+				needType := ref.AffectsInference ||
+					(ref.Assignable && ref.IfaceAssignment && !param.info.IsInterface) ||
+					(!ref.Assignable && !trivialConversion(arg.constant, arg.typ, param.obj.Type()))
+
+				if needType &&
+					!types.Identical(types.Default(arg.typ), param.obj.Type()) {
+
+					// If arg.expr is already an interface call, strip it.
+					if call, ok := argExpr.(*ast.CallExpr); ok && len(call.Args) == 1 {
+						if typ, ok := isConversion(caller.Info, call); ok && isNonTypeParamInterface(typ) {
+							argExpr = call.Args[0]
+						}
+					}
+
+					argExpr = convert(param.fieldType, argExpr)
+					logf("param %q (offset %d): adding explicit %s -> %s conversion around argument",
+						param.info.Name, ref.Offset, arg.typ, param.obj.Type())
+				}
+				replace(ref.Offset, internalastutil.CloneNode(argExpr).(ast.Expr), arg.variadic)
+			}
+			params[i] = nil // substituted
+			args[i] = nil   // substituted
+		}
+	}
+}
+
+// isConversion reports whether the given call is a type conversion, returning
+// (operand, true) if so.
+//
+// If the call is not a conversion, it returns (nil, false).
+func isConversion(info *types.Info, call *ast.CallExpr) (types.Type, bool) {
+	if tv, ok := info.Types[call.Fun]; ok && tv.IsType() {
+		return tv.Type, true
+	}
+	return nil, false
+}
+
+// isNonTypeParamInterface reports whether t is a non-type parameter interface
+// type.
+func isNonTypeParamInterface(t types.Type) bool {
+	return !typeparams.IsTypeParam(t) && types.IsInterface(t)
+}
+
+// isUsedOutsideCall reports whether v is used outside of caller.Call, within
+// the body of caller.enclosingFunc.
+func isUsedOutsideCall(caller *Caller, v *types.Var) bool {
+	used := false
+	ast.Inspect(caller.enclosingFunc.Body, func(n ast.Node) bool {
+		if n == caller.Call {
+			return false
+		}
+		switch n := n.(type) {
+		case *ast.Ident:
+			if use := caller.Info.Uses[n]; use == v {
+				used = true
+			}
+		case *ast.FuncType:
+			// All params are used.
+			for _, fld := range n.Params.List {
+				for _, n := range fld.Names {
+					if def := caller.Info.Defs[n]; def == v {
+						used = true
+					}
+				}
+			}
+		}
+		return !used // keep going until we find a use
+	})
+	return used
+}
+
+// checkFalconConstraints checks whether constant arguments
+// are safe to substitute (e.g. s[i] -> ""[0] is not safe.)
+//
+// Any failed constraint causes us to reject all constant arguments as
+// substitution candidates (by clearing args[i].substitution=false).
+//
+// TODO(adonovan): we could obtain a finer result rejecting only the
+// freevars of each failed constraint, and processing constraints in
+// order of increasing arity, but failures are quite rare.
+func checkFalconConstraints(logf logger, params []*parameter, args []*argument, falcon falconResult, sg substGraph) bool {
+	// Create a dummy package, as this is the only
+	// way to create an environment for CheckExpr.
+	pkg := types.NewPackage("falcon", "falcon")
+
+	// Declare types used by constraints.
+	for _, typ := range falcon.Types {
+		logf("falcon env: type %s %s", typ.Name, types.Typ[typ.Kind])
+		pkg.Scope().Insert(types.NewTypeName(token.NoPos, pkg, typ.Name, types.Typ[typ.Kind]))
+	}
+
+	// Declared constants and variables for for parameters.
+	nconst := 0
+	for i, param := range params {
+		name := param.info.Name
+		if name == "" {
+			continue // unreferenced
+		}
+		arg := args[i]
+		if arg.constant != nil && sg.has(arg) && param.info.FalconType != "" {
+			t := pkg.Scope().Lookup(param.info.FalconType).Type()
+			pkg.Scope().Insert(types.NewConst(token.NoPos, pkg, name, t, arg.constant))
+			logf("falcon env: const %s %s = %v", name, param.info.FalconType, arg.constant)
+			nconst++
+		} else {
+			v := types.NewVar(token.NoPos, pkg, name, arg.typ)
+			typesinternal.SetVarKind(v, typesinternal.PackageVar)
+			pkg.Scope().Insert(v)
+			logf("falcon env: var %s %s", name, arg.typ)
+		}
+	}
+	if nconst == 0 {
+		return false // nothing to do
+	}
+
+	// Parse and evaluate the constraints in the environment.
+	fset := token.NewFileSet()
+	removed := false
+	for _, falcon := range falcon.Constraints {
+		expr, err := parser.ParseExprFrom(fset, "falcon", falcon, 0)
+		if err != nil {
+			panic(fmt.Sprintf("failed to parse falcon constraint %s: %v", falcon, err))
+		}
+		if err := types.CheckExpr(fset, pkg, token.NoPos, expr, nil); err != nil {
+			logf("falcon: constraint %s violated: %v", falcon, err)
+			for j, arg := range args {
+				if arg.constant != nil && sg.has(arg) {
+					logf("keeping param %q due falcon violation", params[j].info.Name)
+					removed = sg.remove(arg) || removed
+				}
+			}
+			break
+		}
+		logf("falcon: constraint %s satisfied", falcon)
+	}
+	return removed
+}
+
+// resolveEffects marks arguments as non-substitutable to resolve
+// hazards resulting from the callee evaluation order described by the
+// effects list.
+//
+// To do this, each argument is categorized as a read (R), write (W),
+// or pure. A hazard occurs when the order of evaluation of a W
+// changes with respect to any R or W. Pure arguments can be
+// effectively ignored, as they can be safely evaluated in any order.
+//
+// The callee effects list contains the index of each parameter in the
+// order it is first evaluated during execution of the callee. In
+// addition, the two special values R∞ and W∞ indicate the relative
+// position of the callee's first non-parameter read and its first
+// effects (or other unknown behavior).
+// For example, the list [0 2 1 R∞ 3 W∞] for func(a, b, c, d)
+// indicates that the callee referenced parameters a, c, and b,
+// followed by an arbitrary read, then parameter d, and finally
+// unknown behavior.
+//
+// When an argument is marked as not substitutable, we say that it is
+// 'bound', in the sense that its evaluation occurs in a binding decl
+// or literalized call. Such bindings always occur in the original
+// callee parameter order.
+//
+// In this context, "resolving hazards" means binding arguments so
+// that they are evaluated in a valid, hazard-free order. A trivial
+// solution to this problem would be to bind all arguments, but of
+// course that's not useful. The goal is to bind as few arguments as
+// possible.
+//
+// The algorithm proceeds by inspecting arguments in reverse parameter
+// order (right to left), preserving the invariant that every
+// higher-ordered argument is either already substituted or does not
+// need to be substituted. At each iteration, if there is an
+// evaluation hazard in the callee effects relative to the current
+// argument, the argument must be bound. Subsequently, if the argument
+// is bound for any reason, each lower-ordered argument must also be
+// bound if either the argument or lower-order argument is a
+// W---otherwise the binding itself would introduce a hazard.
+//
+// Thus, after each iteration, there are no hazards relative to the
+// current argument. Subsequent iterations cannot introduce hazards
+// with that argument because they can result only in additional
+// binding of lower-ordered arguments.
+func resolveEffects(logf logger, args []*argument, effects []int, sg substGraph) bool {
+	effectStr := func(effects bool, idx int) string {
+		i := fmt.Sprint(idx)
+		if idx == len(args) {
+			i = "∞"
+		}
+		return string("RW"[btoi(effects)]) + i
+	}
+	removed := false
+	for i := len(args) - 1; i >= 0; i-- {
+		argi := args[i]
+		if sg.has(argi) && !argi.pure {
+			// i is not bound: check whether it must be bound due to hazards.
+			idx := slices.Index(effects, i)
+			if idx >= 0 {
+				for _, j := range effects[:idx] {
+					var (
+						ji int  // effective param index
+						jw bool // j is a write
+					)
+					if j == winf || j == rinf {
+						jw = j == winf
+						ji = len(args)
+					} else {
+						jw = args[j].effects
+						ji = j
+					}
+					if ji > i && (jw || argi.effects) { // out of order evaluation
+						logf("binding argument %s: preceded by %s",
+							effectStr(argi.effects, i), effectStr(jw, ji))
+
+						removed = sg.remove(argi) || removed
+						break
+					}
+				}
+			}
+		}
+		if !sg.has(argi) {
+			for j := 0; j < i; j++ {
+				argj := args[j]
+				if argj.pure {
+					continue
+				}
+				if (argi.effects || argj.effects) && sg.has(argj) {
+					logf("binding argument %s: %s is bound",
+						effectStr(argj.effects, j), effectStr(argi.effects, i))
+
+					removed = sg.remove(argj) || removed
+				}
+			}
+		}
+	}
+	return removed
+}
+
+// A substGraph is a directed graph representing arguments that may be
+// substituted, provided all of their related arguments (or "dependencies") are
+// also substituted. The candidates arguments for substitution are the keys in
+// this graph, and the edges represent shadowing of free variables of the key
+// by parameters corresponding to the dependency arguments.
+//
+// Any argument not present as a map key is known not to be substitutable. Some
+// arguments may have edges leading to other arguments that are not present in
+// the graph. In this case, those arguments also cannot be substituted, because
+// they have free variables that are shadowed by parameters that cannot be
+// substituted. Calling [substGraph.prune] removes these arguments from the
+// graph.
+//
+// The 'prune' operation is not built into the 'remove' step both because
+// analyses (falcon, effects) need local information about each argument
+// independent of dependencies, and for the efficiency of pruning once en masse
+// after each analysis.
+type substGraph map[*argument][]*argument
+
+// has reports whether arg is a candidate for substitution.
+func (g substGraph) has(arg *argument) bool {
+	_, ok := g[arg]
+	return ok
+}
+
+// remove marks arg as not substitutable, reporting whether the arg was
+// previously substitutable.
+//
+// remove does not have side effects on other arguments that may be
+// unsubstitutable as a result of their dependency being removed.
+// Call [substGraph.prune] to propagate these side effects, removing dependent
+// arguments.
+func (g substGraph) remove(arg *argument) bool {
+	pre := len(g)
+	delete(g, arg)
+	return len(g) < pre
+}
+
+// prune updates the graph to remove any keys that reach other arguments not
+// present in the graph.
+func (g substGraph) prune() {
+	// visit visits the forward transitive closure of arg and reports whether any
+	// missing argument was encountered, removing all nodes on the path to it
+	// from arg.
+	//
+	// The seen map is used for cycle breaking. In the presence of cycles, visit
+	// may report a false positive for an intermediate argument. For example,
+	// consider the following graph, where only a and b are candidates for
+	// substitution (meaning, only a and b are present in the graph).
+	//
+	//   a ↔ b
+	//   ↓
+	//  [c]
+	//
+	// In this case, starting a visit from a, visit(b, seen) may report 'true',
+	// because c has not yet been considered. For this reason, we must guarantee
+	// that visit is called with an empty seen map at least once for each node.
+	var visit func(*argument, map[*argument]unit) bool
+	visit = func(arg *argument, seen map[*argument]unit) bool {
+		deps, ok := g[arg]
+		if !ok {
+			return false
+		}
+		if _, ok := seen[arg]; !ok {
+			seen[arg] = unit{}
+			for _, dep := range deps {
+				if !visit(dep, seen) {
+					delete(g, arg)
+					return false
+				}
+			}
+		}
+		return true
+	}
+	for arg := range g {
+		// Remove any argument that is, or transitively depends upon,
+		// an unsubstitutable argument.
+		//
+		// Each visitation gets a fresh cycle-breaking set.
+		visit(arg, make(map[*argument]unit))
+	}
+}
+
+// updateCalleeParams updates the calleeDecl syntax to remove
+// substituted parameters and move the receiver (if any) to the head
+// of the ordinary parameters.
+func updateCalleeParams(calleeDecl *ast.FuncDecl, params []*parameter) {
+	// The logic is fiddly because of the three forms of ast.Field:
+	//
+	//	func(int), func(x int), func(x, y int)
+	//
+	// Also, ensure that all remaining parameters are named
+	// to avoid a mix of named/unnamed when joining (recv, params...).
+	// func (T) f(int, bool) -> (_ T, _ int, _ bool)
+	// (Strictly, we need do this only for methods and only when
+	// the namednesses of Recv and Params differ; that might be tidier.)
+
+	paramIdx := 0 // index in original parameter list (incl. receiver)
+	var newParams []*ast.Field
+	filterParams := func(field *ast.Field) {
+		var names []*ast.Ident
+		if field.Names == nil {
+			// Unnamed parameter field (e.g. func f(int)
+			if params[paramIdx] != nil {
+				// Give it an explicit name "_" since we will
+				// make the receiver (if any) a regular parameter
+				// and one cannot mix named and unnamed parameters.
+				names = append(names, makeIdent("_"))
+			}
+			paramIdx++
+		} else {
+			// Named parameter field e.g. func f(x, y int)
+			// Remove substituted parameters in place.
+			// If all were substituted, delete field.
+			for _, id := range field.Names {
+				if pinfo := params[paramIdx]; pinfo != nil {
+					// Rename unreferenced parameters with "_".
+					// This is crucial for binding decls, since
+					// unlike parameters, they are subject to
+					// "unreferenced var" checks.
+					if len(pinfo.info.Refs) == 0 {
+						id = makeIdent("_")
+					}
+					names = append(names, id)
+				}
+				paramIdx++
+			}
+		}
+		if names != nil {
+			newParams = append(newParams, &ast.Field{
+				Names: names,
+				Type:  field.Type,
+			})
+		}
+	}
+	if calleeDecl.Recv != nil {
+		filterParams(calleeDecl.Recv.List[0])
+		calleeDecl.Recv = nil
+	}
+	for _, field := range calleeDecl.Type.Params.List {
+		filterParams(field)
+	}
+	calleeDecl.Type.Params.List = newParams
+}
+
+// bindingDeclInfo records information about the binding decl produced by
+// createBindingDecl.
+type bindingDeclInfo struct {
+	names map[string]bool // names bound by the binding decl; possibly empty
+	stmt  ast.Stmt        // the binding decl itself
+}
+
+// createBindingDecl constructs a "binding decl" that implements
+// parameter assignment and declares any named result variables
+// referenced by the callee. It returns nil if there were no
+// unsubstituted parameters.
+//
+// It may not always be possible to create the decl (e.g. due to
+// shadowing), in which case it also returns nil; but if it succeeds,
+// the declaration may be used by reduction strategies to relax the
+// requirement that all parameters have been substituted.
+//
+// For example, a call:
+//
+//	f(a0, a1, a2)
+//
+// where:
+//
+//	func f(p0, p1 T0, p2 T1) { body }
+//
+// reduces to:
+//
+//	{
+//	  var (
+//	    p0, p1 T0 = a0, a1
+//	    p2     T1 = a2
+//	  )
+//	  body
+//	}
+//
+// so long as p0, p1 ∉ freevars(T1) or freevars(a2), and so on,
+// because each spec is statically resolved in sequence and
+// dynamically assigned in sequence. By contrast, all
+// parameters are resolved simultaneously and assigned
+// simultaneously.
+//
+// The pX names should already be blank ("_") if the parameter
+// is unreferenced; this avoids "unreferenced local var" checks.
+//
+// Strategies may impose additional checks on return
+// conversions, labels, defer, etc.
+func createBindingDecl(logf logger, caller *Caller, args []*argument, calleeDecl *ast.FuncDecl, results []*paramInfo) *bindingDeclInfo {
+	// Spread calls are tricky as they may not align with the
+	// parameters' field groupings nor types.
+	// For example, given
+	//   func g() (int, string)
+	// the call
+	//   f(g())
+	// is legal with these decls of f:
+	//   func f(int, string)
+	//   func f(x, y any)
+	//   func f(x, y ...any)
+	// TODO(adonovan): support binding decls for spread calls by
+	// splitting parameter groupings as needed.
+	if lastArg := last(args); lastArg != nil && lastArg.spread {
+		logf("binding decls not yet supported for spread calls")
+		return nil
+	}
+
+	var (
+		specs []ast.Spec
+		names = make(map[string]bool) // names defined by previous specs
+	)
+	// shadow reports whether any name referenced by spec is
+	// shadowed by a name declared by a previous spec (since,
+	// unlike parameters, each spec of a var decl is within the
+	// scope of the previous specs).
+	shadow := func(spec *ast.ValueSpec) bool {
+		// Compute union of free names of type and values
+		// and detect shadowing. Values is the arguments
+		// (caller syntax), so we can use type info.
+		// But Type is the untyped callee syntax,
+		// so we have to use a syntax-only algorithm.
+		free := make(map[string]bool)
+		for _, value := range spec.Values {
+			for name := range freeVars(caller.Info, value) {
+				free[name] = true
+			}
+		}
+		const includeComplitIdents = true
+		freeishNames(free, spec.Type, includeComplitIdents)
+		for name := range free {
+			if names[name] {
+				logf("binding decl would shadow free name %q", name)
+				return true
+			}
+		}
+		for _, id := range spec.Names {
+			if id.Name != "_" {
+				names[id.Name] = true
+			}
+		}
+		return false
+	}
+
+	// parameters
+	//
+	// Bind parameters that were not eliminated through
+	// substitution. (Non-nil arguments correspond to the
+	// remaining parameters in calleeDecl.)
+	var values []ast.Expr
+	for _, arg := range args {
+		if arg != nil {
+			values = append(values, arg.expr)
+		}
+	}
+	for _, field := range calleeDecl.Type.Params.List {
+		// Each field (param group) becomes a ValueSpec.
+		spec := &ast.ValueSpec{
+			Names:  cleanNodes(field.Names),
+			Type:   cleanNode(field.Type),
+			Values: values[:len(field.Names)],
+		}
+		values = values[len(field.Names):]
+		if shadow(spec) {
+			return nil
+		}
+		specs = append(specs, spec)
+	}
+	assert(len(values) == 0, "args/params mismatch")
+
+	// results
+	//
+	// Add specs to declare any named result
+	// variables that are referenced by the body.
+	if calleeDecl.Type.Results != nil {
+		resultIdx := 0
+		for _, field := range calleeDecl.Type.Results.List {
+			if field.Names == nil {
+				resultIdx++
+				continue // unnamed field
+			}
+			var names []*ast.Ident
+			for _, id := range field.Names {
+				if len(results[resultIdx].Refs) > 0 {
+					names = append(names, id)
+				}
+				resultIdx++
+			}
+			if len(names) > 0 {
+				spec := &ast.ValueSpec{
+					Names: cleanNodes(names),
+					Type:  cleanNode(field.Type),
+				}
+				if shadow(spec) {
+					return nil
+				}
+				specs = append(specs, spec)
+			}
+		}
+	}
+
+	if len(specs) == 0 {
+		logf("binding decl not needed: all parameters substituted")
+		return nil
+	}
+
+	stmt := &ast.DeclStmt{
+		Decl: &ast.GenDecl{
+			Tok:   token.VAR,
+			Specs: specs,
+		},
+	}
+	logf("binding decl: %s", debugFormatNode(caller.Fset, stmt))
+	return &bindingDeclInfo{names: names, stmt: stmt}
+}
+
+// lookup does a symbol lookup in the lexical environment of the caller.
+func (caller *Caller) lookup(name string) types.Object {
+	pos := caller.Call.Pos()
+	for _, n := range caller.path {
+		if scope := scopeFor(caller.Info, n); scope != nil {
+			if _, obj := scope.LookupParent(name, pos); obj != nil {
+				return obj
+			}
+		}
+	}
+	return nil
+}
+
+func scopeFor(info *types.Info, n ast.Node) *types.Scope {
+	// The function body scope (containing not just params)
+	// is associated with the function's type, not body.
+	switch fn := n.(type) {
+	case *ast.FuncDecl:
+		n = fn.Type
+	case *ast.FuncLit:
+		n = fn.Type
+	}
+	return info.Scopes[n]
+}
+
+// -- predicates over expressions --
+
+// freeVars returns the names of all free identifiers of e:
+// those lexically referenced by it but not defined within it.
+// (Fields and methods are not included.)
+func freeVars(info *types.Info, e ast.Expr) map[string]bool {
+	free := make(map[string]bool)
+	ast.Inspect(e, func(n ast.Node) bool {
+		if id, ok := n.(*ast.Ident); ok {
+			// The isField check is so that we don't treat T{f: 0} as a ref to f.
+			if obj, ok := info.Uses[id]; ok && !within(obj.Pos(), e) && !isField(obj) {
+				free[obj.Name()] = true
+			}
+		}
+		return true
+	})
+	return free
+}
+
+// effects reports whether an expression might change the state of the
+// program (through function calls and channel receives) and affect
+// the evaluation of subsequent expressions.
+func (st *state) effects(info *types.Info, expr ast.Expr) bool {
+	effects := false
+	ast.Inspect(expr, func(n ast.Node) bool {
+		switch n := n.(type) {
+		case *ast.FuncLit:
+			return false // prune descent
+
+		case *ast.CallExpr:
+			if info.Types[n.Fun].IsType() {
+				// A conversion T(x) has only the effect of its operand.
+			} else if !typesinternal.CallsPureBuiltin(info, n) {
+				// A handful of built-ins have no effect
+				// beyond those of their arguments.
+				// All other calls (including append, copy, recover)
+				// have unknown effects.
+				//
+				// As with 'pure', there is room for
+				// improvement by inspecting the callee.
+				effects = true
+			}
+
+		case *ast.UnaryExpr:
+			if n.Op == token.ARROW { // <-ch
+				effects = true
+			}
+		}
+		return true
+	})
+
+	// Even if consideration of effects is not desired,
+	// we continue to compute, log, and discard them.
+	if st.opts.IgnoreEffects && effects {
+		effects = false
+		st.opts.Logf("ignoring potential effects of argument %s",
+			debugFormatNode(st.caller.Fset, expr))
+	}
+
+	return effects
+}
+
+// pure reports whether an expression has the same result no matter
+// when it is executed relative to other expressions, so it can be
+// commuted with any other expression or statement without changing
+// its meaning.
+//
+// An expression is considered impure if it reads the contents of any
+// variable, with the exception of "single assignment" local variables
+// (as classified by the provided callback), which are never updated
+// after their initialization.
+//
+// Pure does not imply duplicable: for example, new(T) and T{} are
+// pure expressions but both return a different value each time they
+// are evaluated, so they are not safe to duplicate.
+//
+// Purity does not imply freedom from run-time panics. We assume that
+// target programs do not encounter run-time panics nor depend on them
+// for correct operation.
+//
+// TODO(adonovan): add unit tests of this function.
+func pure(info *types.Info, assign1 func(*types.Var) bool, e ast.Expr) bool {
+	var pure func(e ast.Expr) bool
+	pure = func(e ast.Expr) bool {
+		switch e := e.(type) {
+		case *ast.ParenExpr:
+			return pure(e.X)
+
+		case *ast.Ident:
+			if v, ok := info.Uses[e].(*types.Var); ok {
+				// In general variables are impure
+				// as they may be updated, but
+				// single-assignment local variables
+				// never change value.
+				//
+				// We assume all package-level variables
+				// may be updated, but for non-exported
+				// ones we could do better by analyzing
+				// the complete package.
+				return !isPkgLevel(v) && assign1(v)
+			}
+
+			// All other kinds of reference are pure.
+			return true
+
+		case *ast.FuncLit:
+			// A function literal may allocate a closure that
+			// references mutable variables, but mutation
+			// cannot be observed without calling the function,
+			// and calls are considered impure.
+			return true
+
+		case *ast.BasicLit:
+			return true
+
+		case *ast.UnaryExpr: // + - ! ^ & but not <-
+			return e.Op != token.ARROW && pure(e.X)
+
+		case *ast.BinaryExpr: // arithmetic, shifts, comparisons, &&/||
+			return pure(e.X) && pure(e.Y)
+
+		case *ast.CallExpr:
+			// A conversion is as pure as its operand.
+			if info.Types[e.Fun].IsType() {
+				return pure(e.Args[0])
+			}
+
+			// Calls to some built-ins are as pure as their arguments.
+			if typesinternal.CallsPureBuiltin(info, e) {
+				for _, arg := range e.Args {
+					if !pure(arg) {
+						return false
+					}
+				}
+				return true
+			}
+
+			// All other calls are impure, so we can
+			// reject them without even looking at e.Fun.
+			//
+			// More sophisticated analysis could infer purity in
+			// commonly used functions such as strings.Contains;
+			// perhaps we could offer the client a hook so that
+			// go/analysis-based implementation could exploit the
+			// results of a purity analysis. But that would make
+			// the inliner's choices harder to explain.
+			return false
+
+		case *ast.CompositeLit:
+			// T{...} is as pure as its elements.
+			for _, elt := range e.Elts {
+				if kv, ok := elt.(*ast.KeyValueExpr); ok {
+					if !pure(kv.Value) {
+						return false
+					}
+					if id, ok := kv.Key.(*ast.Ident); ok {
+						if v, ok := info.Uses[id].(*types.Var); ok && v.IsField() {
+							continue // struct {field: value}
+						}
+					}
+					// map/slice/array {key: value}
+					if !pure(kv.Key) {
+						return false
+					}
+
+				} else if !pure(elt) {
+					return false
+				}
+			}
+			return true
+
+		case *ast.SelectorExpr:
+			if seln, ok := info.Selections[e]; ok {
+				// See types.SelectionKind for background.
+				switch seln.Kind() {
+				case types.MethodExpr:
+					// A method expression T.f acts like a
+					// reference to a func decl, so it is pure.
+					return true
+
+				case types.MethodVal, types.FieldVal:
+					// A field or method selection x.f is pure
+					// if x is pure and the selection does
+					// not indirect a pointer.
+					return !indirectSelection(seln) && pure(e.X)
+
+				default:
+					panic(seln)
+				}
+			} else {
+				// A qualified identifier is
+				// treated like an unqualified one.
+				return pure(e.Sel)
+			}
+
+		case *ast.StarExpr:
+			return false // *ptr depends on the state of the heap
+
+		default:
+			return false
+		}
+	}
+	return pure(e)
+}
+
+// duplicable reports whether it is appropriate for the expression to
+// be freely duplicated.
+//
+// Given the declaration
+//
+//	func f(x T) T { return x + g() + x }
+//
+// an argument y is considered duplicable if we would wish to see a
+// call f(y) simplified to y+g()+y. This is true for identifiers,
+// integer literals, unary negation, and selectors x.f where x is not
+// a pointer. But we would not wish to duplicate expressions that:
+// - have side effects (e.g. nearly all calls),
+// - are not referentially transparent (e.g. &T{}, ptr.field, *ptr), or
+// - are long (e.g. "huge string literal").
+func duplicable(info *types.Info, e ast.Expr) bool {
+	switch e := e.(type) {
+	case *ast.ParenExpr:
+		return duplicable(info, e.X)
+
+	case *ast.Ident:
+		return true
+
+	case *ast.BasicLit:
+		v := info.Types[e].Value
+		switch e.Kind {
+		case token.INT:
+			return true // any int
+		case token.STRING:
+			return consteq(v, kZeroString) // only ""
+		case token.FLOAT:
+			return consteq(v, kZeroFloat) || consteq(v, kOneFloat) // only 0.0 or 1.0
+		}
+
+	case *ast.UnaryExpr: // e.g. +1, -1
+		return (e.Op == token.ADD || e.Op == token.SUB) && duplicable(info, e.X)
+
+	case *ast.CompositeLit:
+		// Empty struct or array literals T{} are duplicable.
+		// (Non-empty literals are too verbose, and slice/map
+		// literals allocate indirect variables.)
+		if len(e.Elts) == 0 {
+			switch info.TypeOf(e).Underlying().(type) {
+			case *types.Struct, *types.Array:
+				return true
+			}
+		}
+		return false
+
+	case *ast.CallExpr:
+		// Treat type conversions as duplicable if they do not observably allocate.
+		// The only cases of observable allocations are
+		// the `[]byte(string)` and `[]rune(string)` conversions.
+		//
+		// Duplicating string([]byte) conversions increases
+		// allocation but doesn't change behavior, but the
+		// reverse, []byte(string), allocates a distinct array,
+		// which is observable.
+
+		if !info.Types[e.Fun].IsType() { // check whether e.Fun is a type conversion
+			return false
+		}
+
+		fun := info.TypeOf(e.Fun)
+		arg := info.TypeOf(e.Args[0])
+
+		switch fun := fun.Underlying().(type) {
+		case *types.Slice:
+			// Do not mark []byte(string) and []rune(string) as duplicable.
+			elem, ok := fun.Elem().Underlying().(*types.Basic)
+			if ok && (elem.Kind() == types.Rune || elem.Kind() == types.Byte) {
+				from, ok := arg.Underlying().(*types.Basic)
+				isString := ok && from.Info()&types.IsString != 0
+				return !isString
+			}
+		case *types.TypeParam:
+			return false // be conservative
+		}
+		return true
+
+	case *ast.SelectorExpr:
+		if seln, ok := info.Selections[e]; ok {
+			// A field or method selection x.f is referentially
+			// transparent if it does not indirect a pointer.
+			return !indirectSelection(seln)
+		}
+		// A qualified identifier pkg.Name is referentially transparent.
+		return true
+	}
+	return false
+}
+
+func consteq(x, y constant.Value) bool {
+	return constant.Compare(x, token.EQL, y)
+}
+
+var (
+	kZeroInt    = constant.MakeInt64(0)
+	kZeroString = constant.MakeString("")
+	kZeroFloat  = constant.MakeFloat64(0.0)
+	kOneFloat   = constant.MakeFloat64(1.0)
+)
+
+// -- inline helpers --
+
+func assert(cond bool, msg string) {
+	if !cond {
+		panic(msg)
+	}
+}
+
+// blanks returns a slice of n > 0 blank identifiers.
+func blanks[E ast.Expr](n int) []E {
+	if n == 0 {
+		panic("blanks(0)")
+	}
+	res := make([]E, n)
+	for i := range res {
+		res[i] = ast.Expr(makeIdent("_")).(E) // ugh
+	}
+	return res
+}
+
+func makeIdent(name string) *ast.Ident {
+	return &ast.Ident{Name: name}
+}
+
+// importedPkgName returns the PkgName object declared by an ImportSpec.
+// TODO(adonovan): make this a method of types.Info (#62037).
+func importedPkgName(info *types.Info, imp *ast.ImportSpec) (*types.PkgName, bool) {
+	var obj types.Object
+	if imp.Name != nil {
+		obj = info.Defs[imp.Name]
+	} else {
+		obj = info.Implicits[imp]
+	}
+	pkgname, ok := obj.(*types.PkgName)
+	return pkgname, ok
+}
+
+func isPkgLevel(obj types.Object) bool {
+	// TODO(adonovan): consider using the simpler obj.Parent() ==
+	// obj.Pkg().Scope() instead. But be sure to test carefully
+	// with instantiations of generics.
+	return obj.Pkg().Scope().Lookup(obj.Name()) == obj
+}
+
+// callContext returns the two nodes immediately enclosing the call
+// (specified as a PathEnclosingInterval), ignoring parens.
+func callContext(callPath []ast.Node) (parent, grandparent ast.Node) {
+	_ = callPath[0].(*ast.CallExpr) // sanity check
+	for _, n := range callPath[1:] {
+		if !is[*ast.ParenExpr](n) {
+			if parent == nil {
+				parent = n
+			} else {
+				return parent, n
+			}
+		}
+	}
+	return parent, nil
+}
+
+// hasLabelConflict reports whether the set of labels of the function
+// enclosing the call (specified as a PathEnclosingInterval)
+// intersects with the set of callee labels.
+func hasLabelConflict(callPath []ast.Node, calleeLabels []string) bool {
+	labels := callerLabels(callPath)
+	for _, label := range calleeLabels {
+		if labels[label] {
+			return true // conflict
+		}
+	}
+	return false
+}
+
+// callerLabels returns the set of control labels in the function (if
+// any) enclosing the call (specified as a PathEnclosingInterval).
+func callerLabels(callPath []ast.Node) map[string]bool {
+	var callerBody *ast.BlockStmt
+	switch f := callerFunc(callPath).(type) {
+	case *ast.FuncDecl:
+		callerBody = f.Body
+	case *ast.FuncLit:
+		callerBody = f.Body
+	}
+	var labels map[string]bool
+	if callerBody != nil {
+		ast.Inspect(callerBody, func(n ast.Node) bool {
+			switch n := n.(type) {
+			case *ast.FuncLit:
+				return false // prune traversal
+			case *ast.LabeledStmt:
+				if labels == nil {
+					labels = make(map[string]bool)
+				}
+				labels[n.Label.Name] = true
+			}
+			return true
+		})
+	}
+	return labels
+}
+
+// callerFunc returns the innermost Func{Decl,Lit} node enclosing the
+// call (specified as a PathEnclosingInterval).
+func callerFunc(callPath []ast.Node) ast.Node {
+	_ = callPath[0].(*ast.CallExpr) // sanity check
+	for _, n := range callPath[1:] {
+		if is[*ast.FuncDecl](n) || is[*ast.FuncLit](n) {
+			return n
+		}
+	}
+	return nil
+}
+
+// callStmt reports whether the function call (specified
+// as a PathEnclosingInterval) appears within an ExprStmt,
+// and returns it if so.
+//
+// If unrestricted, callStmt returns nil if the ExprStmt f() appears
+// in a restricted context (such as "if f(); cond {") where it cannot
+// be replaced by an arbitrary statement. (See "statement theory".)
+func callStmt(callPath []ast.Node, unrestricted bool) *ast.ExprStmt {
+	parent, _ := callContext(callPath)
+	stmt, ok := parent.(*ast.ExprStmt)
+	if ok && unrestricted {
+		switch callPath[slices.Index(callPath, ast.Node(stmt))+1].(type) {
+		case *ast.LabeledStmt,
+			*ast.BlockStmt,
+			*ast.CaseClause,
+			*ast.CommClause:
+			// unrestricted
+		default:
+			// TODO(adonovan): handle restricted
+			// XYZStmt.Init contexts (but not ForStmt.Post)
+			// by creating a block around the if/for/switch:
+			// "if f(); cond {"  ->  "{ stmts; if cond {"
+
+			return nil // restricted
+		}
+	}
+	return stmt
+}
+
+// Statement theory
+//
+// These are all the places a statement may appear in the AST:
+//
+// LabeledStmt.Stmt       Stmt      -- any
+// BlockStmt.List       []Stmt      -- any (but see switch/select)
+// IfStmt.Init            Stmt?     -- simple
+// IfStmt.Body            BlockStmt
+// IfStmt.Else            Stmt?     -- IfStmt or BlockStmt
+// CaseClause.Body      []Stmt      -- any
+// SwitchStmt.Init        Stmt?     -- simple
+// SwitchStmt.Body        BlockStmt -- CaseClauses only
+// TypeSwitchStmt.Init    Stmt?     -- simple
+// TypeSwitchStmt.Assign  Stmt      -- AssignStmt(TypeAssertExpr) or ExprStmt(TypeAssertExpr)
+// TypeSwitchStmt.Body    BlockStmt -- CaseClauses only
+// CommClause.Comm        Stmt?     -- SendStmt or ExprStmt(UnaryExpr) or AssignStmt(UnaryExpr)
+// CommClause.Body      []Stmt      -- any
+// SelectStmt.Body        BlockStmt -- CommClauses only
+// ForStmt.Init           Stmt?     -- simple
+// ForStmt.Post           Stmt?     -- simple
+// ForStmt.Body           BlockStmt
+// RangeStmt.Body         BlockStmt
+//
+// simple = AssignStmt | SendStmt | IncDecStmt | ExprStmt.
+//
+// A BlockStmt cannot replace an ExprStmt in
+// {If,Switch,TypeSwitch}Stmt.Init or ForStmt.Post.
+// That is allowed only within:
+//   LabeledStmt.Stmt       Stmt
+//   BlockStmt.List       []Stmt
+//   CaseClause.Body      []Stmt
+//   CommClause.Body      []Stmt
+
+// replaceNode performs a destructive update of the tree rooted at
+// root, replacing each occurrence of "from" with "to". If to is nil and
+// the element is within a slice, the slice element is removed.
+//
+// The root itself cannot be replaced; an attempt will panic.
+//
+// This function must not be called on the caller's syntax tree.
+//
+// TODO(adonovan): polish this up and move it to astutil package.
+// TODO(adonovan): needs a unit test.
+func replaceNode(root ast.Node, from, to ast.Node) {
+	if from == nil {
+		panic("from == nil")
+	}
+	if reflect.ValueOf(from).IsNil() {
+		panic(fmt.Sprintf("from == (%T)(nil)", from))
+	}
+	if from == root {
+		panic("from == root")
+	}
+	found := false
+	var parent reflect.Value // parent variable of interface type, containing a pointer
+	var visit func(reflect.Value)
+	visit = func(v reflect.Value) {
+		switch v.Kind() {
+		case reflect.Pointer:
+			if v.Interface() == from {
+				found = true
+
+				// If v is a struct field or array element
+				// (e.g. Field.Comment or Field.Names[i])
+				// then it is addressable (a pointer variable).
+				//
+				// But if it was the value an interface
+				// (e.g. *ast.Ident within ast.Node)
+				// then it is non-addressable, and we need
+				// to set the enclosing interface (parent).
+				if !v.CanAddr() {
+					v = parent
+				}
+
+				// to=nil => use zero value
+				var toV reflect.Value
+				if to != nil {
+					toV = reflect.ValueOf(to)
+				} else {
+					toV = reflect.Zero(v.Type()) // e.g. ast.Expr(nil)
+				}
+				v.Set(toV)
+
+			} else if !v.IsNil() {
+				switch v.Interface().(type) {
+				case *ast.Object, *ast.Scope:
+					// Skip fields of types potentially involved in cycles.
+				default:
+					visit(v.Elem())
+				}
+			}
+
+		case reflect.Struct:
+			for i := range v.Type().NumField() {
+				visit(v.Field(i))
+			}
+
+		case reflect.Slice:
+			compact := false
+			for i := range v.Len() {
+				visit(v.Index(i))
+				if v.Index(i).IsNil() {
+					compact = true
+				}
+			}
+			if compact {
+				// Elements were deleted. Eliminate nils.
+				// (Do this is a second pass to avoid
+				// unnecessary writes in the common case.)
+				j := 0
+				for i := range v.Len() {
+					if !v.Index(i).IsNil() {
+						v.Index(j).Set(v.Index(i))
+						j++
+					}
+				}
+				v.SetLen(j)
+			}
+		case reflect.Interface:
+			parent = v
+			visit(v.Elem())
+
+		case reflect.Array, reflect.Chan, reflect.Func, reflect.Map, reflect.UnsafePointer:
+			panic(v) // unreachable in AST
+		default:
+			// bool, string, number: nop
+		}
+		parent = reflect.Value{}
+	}
+	visit(reflect.ValueOf(root))
+	if !found {
+		panic(fmt.Sprintf("%T not found", from))
+	}
+}
+
+// cleanNode returns a clone of node with positions cleared.
+//
+// It should be used for any callee nodes that are formatted using the caller
+// file set.
+func cleanNode[T ast.Node](node T) T {
+	clone := internalastutil.CloneNode(node)
+	clearPositions(clone)
+	return clone
+}
+
+func cleanNodes[T ast.Node](nodes []T) []T {
+	var clean []T
+	for _, node := range nodes {
+		clean = append(clean, cleanNode(node))
+	}
+	return clean
+}
+
+// clearPositions destroys token.Pos information within the tree rooted at root,
+// as positions in callee trees may cause caller comments to be emitted prematurely.
+//
+// In general it isn't safe to clear a valid Pos because some of them
+// (e.g. CallExpr.Ellipsis, TypeSpec.Assign) are significant to
+// go/printer, so this function sets each non-zero Pos to 1, which
+// suffices to avoid advancing the printer's comment cursor.
+//
+// This function mutates its argument; do not invoke on caller syntax.
+//
+// TODO(adonovan): remove this horrendous workaround when #20744 is finally fixed.
+func clearPositions(root ast.Node) {
+	posType := reflect.TypeFor[token.Pos]()
+	ast.Inspect(root, func(n ast.Node) bool {
+		if n != nil {
+			v := reflect.ValueOf(n).Elem() // deref the pointer to struct
+			fields := v.Type().NumField()
+			for i := range fields {
+				f := v.Field(i)
+				// Clearing Pos arbitrarily is destructive,
+				// as its presence may be semantically significant
+				// (e.g. CallExpr.Ellipsis, TypeSpec.Assign)
+				// or affect formatting preferences (e.g. GenDecl.Lparen).
+				//
+				// Note: for proper formatting, it may be necessary to be selective
+				// about which positions we set to 1 vs which we set to token.NoPos.
+				// (e.g. we can set most to token.NoPos, save the few that are
+				// significant).
+				if f.Type() == posType {
+					if f.Interface() != token.NoPos {
+						f.Set(reflect.ValueOf(token.Pos(1)))
+					}
+				}
+			}
+		}
+		return true
+	})
+}
+
+// findIdent finds the Ident beneath root that has the given pos.
+// It returns the path to the ident (excluding the ident), and the ident
+// itself, where the path is the sequence of ast.Nodes encountered in a
+// depth-first search to find ident.
+func findIdent(root ast.Node, pos token.Pos) ([]ast.Node, *ast.Ident) {
+	// TODO(adonovan): opt: skip subtrees that don't contain pos.
+	var (
+		path  []ast.Node
+		found *ast.Ident
+	)
+	ast.Inspect(root, func(n ast.Node) bool {
+		if found != nil {
+			return false
+		}
+		if n == nil {
+			path = path[:len(path)-1]
+			return false
+		}
+		if id, ok := n.(*ast.Ident); ok {
+			if id.Pos() == pos {
+				found = id
+				return true
+			}
+		}
+		path = append(path, n)
+		return true
+	})
+	if found == nil {
+		panic(fmt.Sprintf("findIdent %d not found in %s",
+			pos, debugFormatNode(token.NewFileSet(), root)))
+	}
+	return path, found
+}
+
+func prepend[T any](elem T, slice ...T) []T {
+	return append([]T{elem}, slice...)
+}
+
+// debugFormatNode formats a node or returns a formatting error.
+// Its sloppy treatment of errors is appropriate only for logging.
+func debugFormatNode(fset *token.FileSet, n ast.Node) string {
+	var out strings.Builder
+	if err := format.Node(&out, fset, n); err != nil {
+		out.WriteString(err.Error())
+	}
+	return out.String()
+}
+
+func shallowCopy[T any](ptr *T) *T {
+	copy := *ptr
+	return ©
+}
+
+// ∀
+func forall[T any](list []T, f func(i int, x T) bool) bool {
+	for i, x := range list {
+		if !f(i, x) {
+			return false
+		}
+	}
+	return true
+}
+
+// ∃
+func exists[T any](list []T, f func(i int, x T) bool) bool {
+	for i, x := range list {
+		if f(i, x) {
+			return true
+		}
+	}
+	return false
+}
+
+// last returns the last element of a slice, or zero if empty.
+func last[T any](slice []T) T {
+	n := len(slice)
+	if n > 0 {
+		return slice[n-1]
+	}
+	return *new(T)
+}
+
+// consistentOffsets reports whether the portion of caller.Content
+// that corresponds to caller.Call can be parsed as a call expression.
+// If not, the client has provided inconsistent information, possibly
+// because they forgot to ignore line directives when computing the
+// filename enclosing the call.
+// This is just a heuristic.
+func consistentOffsets(caller *Caller) bool {
+	start := offsetOf(caller.Fset, caller.Call.Pos())
+	end := offsetOf(caller.Fset, caller.Call.End())
+	if !(0 < start && start < end && end <= len(caller.Content)) {
+		return false
+	}
+	expr, err := parser.ParseExpr(string(caller.Content[start:end]))
+	if err != nil {
+		return false
+	}
+	return is[*ast.CallExpr](expr)
+}
+
+// needsParens reports whether parens are required to avoid ambiguity
+// around the new node replacing the specified old node (which is some
+// ancestor of the CallExpr identified by its PathEnclosingInterval).
+func needsParens(callPath []ast.Node, old, new ast.Node) bool {
+	// Find enclosing old node and its parent.
+	i := slices.Index(callPath, old)
+	if i == -1 {
+		panic("not found")
+	}
+
+	// There is no precedence ambiguity when replacing
+	// (e.g.) a statement enclosing the call.
+	if !is[ast.Expr](old) {
+		return false
+	}
+
+	// An expression beneath a non-expression
+	// has no precedence ambiguity.
+	parent, ok := callPath[i+1].(ast.Expr)
+	if !ok {
+		return false
+	}
+
+	precedence := func(n ast.Node) int {
+		switch n := n.(type) {
+		case *ast.UnaryExpr, *ast.StarExpr:
+			return token.UnaryPrec
+		case *ast.BinaryExpr:
+			return n.Op.Precedence()
+		}
+		return -1
+	}
+
+	// Parens are not required if the new node
+	// is not unary or binary.
+	newprec := precedence(new)
+	if newprec < 0 {
+		return false
+	}
+
+	// Parens are required if parent and child are both
+	// unary or binary and the parent has higher precedence.
+	if precedence(parent) > newprec {
+		return true
+	}
+
+	// Was the old node the operand of a postfix operator?
+	//  f().sel
+	//  f()[i:j]
+	//  f()[i]
+	//  f().(T)
+	//  f()(x)
+	switch parent := parent.(type) {
+	case *ast.SelectorExpr:
+		return parent.X == old
+	case *ast.IndexExpr:
+		return parent.X == old
+	case *ast.SliceExpr:
+		return parent.X == old
+	case *ast.TypeAssertExpr:
+		return parent.X == old
+	case *ast.CallExpr:
+		return parent.Fun == old
+	}
+	return false
+}
+
+// declares returns the set of lexical names declared by a
+// sequence of statements from the same block, excluding sub-blocks.
+// (Lexical names do not include control labels.)
+func declares(stmts []ast.Stmt) map[string]bool {
+	names := make(map[string]bool)
+	for _, stmt := range stmts {
+		switch stmt := stmt.(type) {
+		case *ast.DeclStmt:
+			for _, spec := range stmt.Decl.(*ast.GenDecl).Specs {
+				switch spec := spec.(type) {
+				case *ast.ValueSpec:
+					for _, id := range spec.Names {
+						names[id.Name] = true
+					}
+				case *ast.TypeSpec:
+					names[spec.Name.Name] = true
+				}
+			}
+
+		case *ast.AssignStmt:
+			if stmt.Tok == token.DEFINE {
+				for _, lhs := range stmt.Lhs {
+					names[lhs.(*ast.Ident).Name] = true
+				}
+			}
+		}
+	}
+	delete(names, "_")
+	return names
+}
+
+// A importNameFunc is used to query local import names in the caller, in a
+// particular shadowing context.
+//
+// The shadow map contains additional names shadowed in the inlined code, at
+// the position the local import name is to be used. The shadow map only needs
+// to contain newly introduced names in the inlined code; names shadowed at the
+// caller are handled automatically.
+type importNameFunc = func(pkgPath string, shadow shadowMap) string
+
+// assignStmts rewrites a statement assigning the results of a call into zero
+// or more statements that assign its return operands, or (nil, false) if no
+// such rewrite is possible. The set of bindings created by the result of
+// assignStmts is the same as the set of bindings created by the callerStmt.
+//
+// The callee must contain exactly one return statement.
+//
+// This is (once again) a surprisingly complex task. For example, depending on
+// types and existing bindings, the assignment
+//
+//	a, b := f()
+//
+// could be rewritten as:
+//
+//	a, b := 1, 2
+//
+// but may need to be written as:
+//
+//	a, b := int8(1), int32(2)
+//
+// In the case where the return statement within f is a spread call to another
+// function g(), we cannot explicitly convert the return values inline, and so
+// it may be necessary to split the declaration and assignment of variables
+// into separate statements:
+//
+//	a, b := g()
+//
+// or
+//
+//	var a int32
+//	a, b = g()
+//
+// or
+//
+//	var (
+//		a int8
+//		b int32
+//	)
+//	a, b = g()
+//
+// Note: assignStmts may return (nil, true) if it determines that the rewritten
+// assignment consists only of _ = nil assignments.
+func (st *state) assignStmts(callerStmt *ast.AssignStmt, returnOperands []ast.Expr, importName importNameFunc) ([]ast.Stmt, bool) {
+	logf, caller, callee := st.opts.Logf, st.caller, &st.callee.impl
+
+	assert(len(callee.Returns) == 1, "unexpected multiple returns")
+	resultInfo := callee.Returns[0]
+
+	// When constructing assign statements, we need to make sure that we don't
+	// modify types on the left-hand side, such as would happen if the type of a
+	// RHS expression does not match the corresponding LHS type at the caller
+	// (due to untyped conversion or interface widening).
+	//
+	// This turns out to be remarkably tricky to handle correctly.
+	//
+	// Substrategies below are labeled as `Substrategy :`.
+
+	// Collect LHS information.
+	var (
+		lhs    []ast.Expr                                // shallow copy of the LHS slice, for mutation
+		defs   = make([]*ast.Ident, len(callerStmt.Lhs)) // indexes in lhs of defining identifiers
+		blanks = make([]bool, len(callerStmt.Lhs))       // indexes in lhs of blank identifiers
+		byType typeutil.Map                              // map of distinct types -> indexes, for writing specs later
+	)
+	for i, expr := range callerStmt.Lhs {
+		lhs = append(lhs, expr)
+		if name, ok := expr.(*ast.Ident); ok {
+			if name.Name == "_" {
+				blanks[i] = true
+				continue // no type
+			}
+
+			if obj, isDef := caller.Info.Defs[name]; isDef {
+				defs[i] = name
+				typ := obj.Type()
+				idxs, _ := byType.At(typ).([]int)
+				idxs = append(idxs, i)
+				byType.Set(typ, idxs)
+			}
+		}
+	}
+
+	// Collect RHS information
+	//
+	// The RHS is either a parallel assignment or spread assignment, but by
+	// looping over both callerStmt.Rhs and returnOperands we handle both.
+	var (
+		rhs             []ast.Expr              // new RHS of assignment, owned by the inliner
+		callIdx         = -1                    // index of the call among the original RHS
+		nilBlankAssigns = make(map[int]unit)    // indexes in rhs of _ = nil assignments, which can be deleted
+		freeNames       = make(map[string]bool) // free(ish) names among rhs expressions
+		nonTrivial      = make(map[int]bool)    // indexes in rhs of nontrivial result conversions
+	)
+	const includeComplitIdents = true
+
+	for i, expr := range callerStmt.Rhs {
+		if expr == caller.Call {
+			assert(callIdx == -1, "malformed (duplicative) AST")
+			callIdx = i
+			for j, returnOperand := range returnOperands {
+				freeishNames(freeNames, returnOperand, includeComplitIdents)
+				rhs = append(rhs, returnOperand)
+				if resultInfo[j]&nonTrivialResult != 0 {
+					nonTrivial[i+j] = true
+				}
+				if blanks[i+j] && resultInfo[j]&untypedNilResult != 0 {
+					nilBlankAssigns[i+j] = unit{}
+				}
+			}
+		} else {
+			// We must clone before clearing positions, since e came from the caller.
+			expr = internalastutil.CloneNode(expr)
+			clearPositions(expr)
+			freeishNames(freeNames, expr, includeComplitIdents)
+			rhs = append(rhs, expr)
+		}
+	}
+	assert(callIdx >= 0, "failed to find call in RHS")
+
+	// Substrategy "splice": Check to see if we can simply splice in the result
+	// expressions from the callee, such as simplifying
+	//
+	//  x, y := f()
+	//
+	// to
+	//
+	//  x, y := e1, e2
+	//
+	// where the types of x and y match the types of e1 and e2.
+	//
+	// This works as long as we don't need to write any additional type
+	// information.
+	if len(nonTrivial) == 0 { // no non-trivial conversions to worry about
+
+		logf("substrategy: splice assignment")
+		return []ast.Stmt{&ast.AssignStmt{
+			Lhs:    lhs,
+			Tok:    callerStmt.Tok,
+			TokPos: callerStmt.TokPos,
+			Rhs:    rhs,
+		}}, true
+	}
+
+	// Inlining techniques below will need to write type information in order to
+	// preserve the correct types of LHS identifiers.
+	//
+	// typeExpr is a simple helper to write out type expressions. It currently
+	// handles (possibly qualified) type names.
+	//
+	// TODO(rfindley):
+	//   1. expand this to handle more type expressions.
+	//   2. refactor to share logic with callee rewriting.
+	universeAny := types.Universe.Lookup("any")
+	typeExpr := func(typ types.Type, shadow shadowMap) ast.Expr {
+		var (
+			typeName string
+			obj      *types.TypeName // nil for basic types
+		)
+		if tname := typesinternal.TypeNameFor(typ); tname != nil {
+			obj = tname
+			typeName = tname.Name()
+		}
+
+		// Special case: check for universe "any".
+		// TODO(golang/go#66921): this may become unnecessary if any becomes a proper alias.
+		if typ == universeAny.Type() {
+			typeName = "any"
+		}
+
+		if typeName == "" {
+			return nil
+		}
+
+		if obj == nil || obj.Pkg() == nil || obj.Pkg() == caller.Types { // local type or builtin
+			if shadow[typeName] != 0 {
+				logf("cannot write shadowed type name %q", typeName)
+				return nil
+			}
+			obj, _ := caller.lookup(typeName).(*types.TypeName)
+			if obj != nil && types.Identical(obj.Type(), typ) {
+				return ast.NewIdent(typeName)
+			}
+		} else if pkgName := importName(obj.Pkg().Path(), shadow); pkgName != "" {
+			return &ast.SelectorExpr{
+				X:   ast.NewIdent(pkgName),
+				Sel: ast.NewIdent(typeName),
+			}
+		}
+		return nil
+	}
+
+	// Substrategy "spread": in the case of a spread call (func f() (T1, T2) return
+	// g()), since we didn't hit the 'splice' substrategy, there must be some
+	// non-declaring expression on the LHS. Simplify this by pre-declaring
+	// variables, rewriting
+	//
+	//   x, y := f()
+	//
+	// to
+	//
+	//  var x int
+	//  x, y = g()
+	//
+	// Which works as long as the predeclared variables do not overlap with free
+	// names on the RHS.
+	if len(rhs) != len(lhs) {
+		assert(len(rhs) == 1 && len(returnOperands) == 1, "expected spread call")
+
+		for _, id := range defs {
+			if id != nil && freeNames[id.Name] {
+				// By predeclaring variables, we're changing them to be in scope of the
+				// RHS. We can't do this if their names are free on the RHS.
+				return nil, false
+			}
+		}
+
+		// Write out the specs, being careful to avoid shadowing free names in
+		// their type expressions.
+		var (
+			specs    []ast.Spec
+			specIdxs []int
+			shadow   = make(shadowMap)
+		)
+		failed := false
+		byType.Iterate(func(typ types.Type, v any) {
+			if failed {
+				return
+			}
+			idxs := v.([]int)
+			specIdxs = append(specIdxs, idxs[0])
+			texpr := typeExpr(typ, shadow)
+			if texpr == nil {
+				failed = true
+				return
+			}
+			spec := &ast.ValueSpec{
+				Type: texpr,
+			}
+			for _, idx := range idxs {
+				spec.Names = append(spec.Names, ast.NewIdent(defs[idx].Name))
+			}
+			specs = append(specs, spec)
+		})
+		if failed {
+			return nil, false
+		}
+		logf("substrategy: spread assignment")
+		return []ast.Stmt{
+			&ast.DeclStmt{
+				Decl: &ast.GenDecl{
+					Tok:   token.VAR,
+					Specs: specs,
+				},
+			},
+			&ast.AssignStmt{
+				Lhs: callerStmt.Lhs,
+				Tok: token.ASSIGN,
+				Rhs: returnOperands,
+			},
+		}, true
+	}
+
+	assert(len(lhs) == len(rhs), "mismatching LHS and RHS")
+
+	// Substrategy "convert": write out RHS expressions with explicit type conversions
+	// as necessary, rewriting
+	//
+	//  x, y := f()
+	//
+	// to
+	//
+	//  x, y := 1, int32(2)
+	//
+	// As required to preserve types.
+	//
+	// In the special case of _ = nil, which is disallowed by the type checker
+	// (since nil has no default type), we delete the assignment.
+	var origIdxs []int // maps back to original indexes after lhs and rhs are pruned
+	i := 0
+	for j := range lhs {
+		if _, ok := nilBlankAssigns[j]; !ok {
+			lhs[i] = lhs[j]
+			rhs[i] = rhs[j]
+			origIdxs = append(origIdxs, j)
+			i++
+		}
+	}
+	lhs = lhs[:i]
+	rhs = rhs[:i]
+
+	if len(lhs) == 0 {
+		logf("trivial assignment after pruning nil blanks assigns")
+		// After pruning, we have no remaining assignments.
+		// Signal this by returning a non-nil slice of statements.
+		return nil, true
+	}
+
+	// Write out explicit conversions as necessary.
+	//
+	// A conversion is necessary if the LHS is being defined, and the RHS return
+	// involved a nontrivial implicit conversion.
+	for i, expr := range rhs {
+		idx := origIdxs[i]
+		if nonTrivial[idx] && defs[idx] != nil {
+			typ := caller.Info.TypeOf(lhs[i])
+			texpr := typeExpr(typ, nil)
+			if texpr == nil {
+				return nil, false
+			}
+			if _, ok := texpr.(*ast.StarExpr); ok {
+				// TODO(rfindley): is this necessary? Doesn't the formatter add these parens?
+				texpr = &ast.ParenExpr{X: texpr} // *T -> (*T)   so that (*T)(x) is valid
+			}
+			rhs[i] = &ast.CallExpr{
+				Fun:  texpr,
+				Args: []ast.Expr{expr},
+			}
+		}
+	}
+	logf("substrategy: convert assignment")
+	return []ast.Stmt{&ast.AssignStmt{
+		Lhs: lhs,
+		Tok: callerStmt.Tok,
+		Rhs: rhs,
+	}}, true
+}
+
+// tailCallSafeReturn reports whether the callee's return statements may be safely
+// used to return from the function enclosing the caller (which must exist).
+func tailCallSafeReturn(caller *Caller, calleeSymbol *types.Func, callee *gobCallee) bool {
+	// It is safe if all callee returns involve only trivial conversions.
+	if !hasNonTrivialReturn(callee.Returns) {
+		return true
+	}
+
+	var callerType types.Type
+	// Find type of innermost function enclosing call.
+	// (Beware: Caller.enclosingFunc is the outermost.)
+loop:
+	for _, n := range caller.path {
+		switch f := n.(type) {
+		case *ast.FuncDecl:
+			callerType = caller.Info.ObjectOf(f.Name).Type()
+			break loop
+		case *ast.FuncLit:
+			callerType = caller.Info.TypeOf(f)
+			break loop
+		}
+	}
+
+	// Non-trivial return conversions in the callee are permitted
+	// if the same non-trivial conversion would occur after inlining,
+	// i.e. if the caller and callee results tuples are identical.
+	callerResults := callerType.(*types.Signature).Results()
+	calleeResults := calleeSymbol.Type().(*types.Signature).Results()
+	return types.Identical(callerResults, calleeResults)
+}
+
+// hasNonTrivialReturn reports whether any of the returns involve a nontrivial
+// implicit conversion of a result expression.
+func hasNonTrivialReturn(returnInfo [][]returnOperandFlags) bool {
+	for _, resultInfo := range returnInfo {
+		for _, r := range resultInfo {
+			if r&nonTrivialResult != 0 {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// soleUse returns the ident that refers to obj, if there is exactly one.
+func soleUse(info *types.Info, obj types.Object) (sole *ast.Ident) {
+	// This is not efficient, but it is called infrequently.
+	for id, obj2 := range info.Uses {
+		if obj2 == obj {
+			if sole != nil {
+				return nil // not unique
+			}
+			sole = id
+		}
+	}
+	return sole
+}
+
+type unit struct{} // for representing sets as maps
diff --git a/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/util.go b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/util.go
new file mode 100644
index 00000000000000..205e5b6aad45e6
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/internal/refactor/inline/util.go
@@ -0,0 +1,168 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package inline
+
+// This file defines various common helpers.
+
+import (
+	"go/ast"
+	"go/constant"
+	"go/token"
+	"go/types"
+	"reflect"
+	"strings"
+
+	"golang.org/x/tools/internal/typeparams"
+)
+
+func is[T any](x any) bool {
+	_, ok := x.(T)
+	return ok
+}
+
+func btoi(b bool) int {
+	if b {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+func offsetOf(fset *token.FileSet, pos token.Pos) int {
+	return fset.PositionFor(pos, false).Offset
+}
+
+// objectKind returns an object's kind (e.g. var, func, const, typename).
+func objectKind(obj types.Object) string {
+	return strings.TrimPrefix(strings.ToLower(reflect.TypeOf(obj).String()), "*types.")
+}
+
+// within reports whether pos is within the half-open interval [n.Pos, n.End).
+func within(pos token.Pos, n ast.Node) bool {
+	return n.Pos() <= pos && pos < n.End()
+}
+
+// trivialConversion reports whether it is safe to omit the implicit
+// value-to-variable conversion that occurs in argument passing or
+// result return. The only case currently allowed is converting from
+// untyped constant to its default type (e.g. 0 to int).
+//
+// The reason for this check is that converting from A to B to C may
+// yield a different result than converting A directly to C: consider
+// 0 to int32 to any.
+//
+// trivialConversion under-approximates trivial conversions, as unfortunately
+// go/types does not record the type of an expression *before* it is implicitly
+// converted, and therefore it cannot distinguish typed constant
+// expressions from untyped constant expressions. For example, in the
+// expression `c + 2`, where c is a uint32 constant, trivialConversion does not
+// detect that the default type of this expression is actually uint32, not untyped
+// int.
+//
+// We could, of course, do better here by reverse engineering some of go/types'
+// constant handling. That may or may not be worthwhile.
+//
+// Example: in func f() int32 { return 0 },
+// the type recorded for 0 is int32, not untyped int;
+// although it is Identical to the result var,
+// the conversion is non-trivial.
+func trivialConversion(fromValue constant.Value, from, to types.Type) bool {
+	if fromValue != nil {
+		var defaultType types.Type
+		switch fromValue.Kind() {
+		case constant.Bool:
+			defaultType = types.Typ[types.Bool]
+		case constant.String:
+			defaultType = types.Typ[types.String]
+		case constant.Int:
+			defaultType = types.Typ[types.Int]
+		case constant.Float:
+			defaultType = types.Typ[types.Float64]
+		case constant.Complex:
+			defaultType = types.Typ[types.Complex128]
+		default:
+			return false
+		}
+		return types.Identical(defaultType, to)
+	}
+	return types.Identical(from, to)
+}
+
+func checkInfoFields(info *types.Info) {
+	assert(info.Defs != nil, "types.Info.Defs is nil")
+	assert(info.Implicits != nil, "types.Info.Implicits is nil")
+	assert(info.Scopes != nil, "types.Info.Scopes is nil")
+	assert(info.Selections != nil, "types.Info.Selections is nil")
+	assert(info.Types != nil, "types.Info.Types is nil")
+	assert(info.Uses != nil, "types.Info.Uses is nil")
+}
+
+// intersects reports whether the maps' key sets intersect.
+func intersects[K comparable, T1, T2 any](x map[K]T1, y map[K]T2) bool {
+	if len(x) > len(y) {
+		return intersects(y, x)
+	}
+	for k := range x {
+		if _, ok := y[k]; ok {
+			return true
+		}
+	}
+	return false
+}
+
+// convert returns syntax for the conversion T(x).
+func convert(T, x ast.Expr) *ast.CallExpr {
+	// The formatter generally adds parens as needed,
+	// but before go1.22 it had a bug (#63362) for
+	// channel types that requires this workaround.
+	if ch, ok := T.(*ast.ChanType); ok && ch.Dir == ast.RECV {
+		T = &ast.ParenExpr{X: T}
+	}
+	return &ast.CallExpr{
+		Fun:  T,
+		Args: []ast.Expr{x},
+	}
+}
+
+// isPointer reports whether t's core type is a pointer.
+func isPointer(t types.Type) bool {
+	return is[*types.Pointer](typeparams.CoreType(t))
+}
+
+// indirectSelection is like seln.Indirect() without bug #8353.
+func indirectSelection(seln *types.Selection) bool {
+	// Work around bug #8353 in Selection.Indirect when Kind=MethodVal.
+	if seln.Kind() == types.MethodVal {
+		tArg, indirect := effectiveReceiver(seln)
+		if indirect {
+			return true
+		}
+
+		tParam := seln.Obj().Type().Underlying().(*types.Signature).Recv().Type()
+		return isPointer(tArg) && !isPointer(tParam) // implicit *
+	}
+
+	return seln.Indirect()
+}
+
+// effectiveReceiver returns the effective type of the method
+// receiver after all implicit field selections (but not implicit * or
+// & operations) have been applied.
+//
+// The boolean indicates whether any implicit field selection was indirect.
+func effectiveReceiver(seln *types.Selection) (types.Type, bool) {
+	assert(seln.Kind() == types.MethodVal, "not MethodVal")
+	t := seln.Recv()
+	indices := seln.Index()
+	indirect := false
+	for _, index := range indices[:len(indices)-1] {
+		if isPointer(t) {
+			indirect = true
+			t = typeparams.MustDeref(t)
+		}
+		t = typeparams.CoreType(t).(*types.Struct).Field(index).Type()
+	}
+	return t, indirect
+}
diff --git a/src/cmd/vendor/modules.txt b/src/cmd/vendor/modules.txt
index f4c60cc3281b78..7ae23d5b6cecf0 100644
--- a/src/cmd/vendor/modules.txt
+++ b/src/cmd/vendor/modules.txt
@@ -96,9 +96,12 @@ golang.org/x/tools/go/analysis/passes/framepointer
 golang.org/x/tools/go/analysis/passes/hostport
 golang.org/x/tools/go/analysis/passes/httpresponse
 golang.org/x/tools/go/analysis/passes/ifaceassert
+golang.org/x/tools/go/analysis/passes/inline
 golang.org/x/tools/go/analysis/passes/inspect
+golang.org/x/tools/go/analysis/passes/internal/gofixdirective
 golang.org/x/tools/go/analysis/passes/loopclosure
 golang.org/x/tools/go/analysis/passes/lostcancel
+golang.org/x/tools/go/analysis/passes/modernize
 golang.org/x/tools/go/analysis/passes/nilfunc
 golang.org/x/tools/go/analysis/passes/printf
 golang.org/x/tools/go/analysis/passes/shift
@@ -117,6 +120,7 @@ golang.org/x/tools/go/analysis/passes/unsafeptr
 golang.org/x/tools/go/analysis/passes/unusedresult
 golang.org/x/tools/go/analysis/passes/waitgroup
 golang.org/x/tools/go/analysis/unitchecker
+golang.org/x/tools/go/ast/astutil
 golang.org/x/tools/go/ast/edge
 golang.org/x/tools/go/ast/inspector
 golang.org/x/tools/go/cfg
@@ -124,6 +128,7 @@ golang.org/x/tools/go/types/objectpath
 golang.org/x/tools/go/types/typeutil
 golang.org/x/tools/internal/aliases
 golang.org/x/tools/internal/analysisinternal
+golang.org/x/tools/internal/analysisinternal/generated
 golang.org/x/tools/internal/analysisinternal/typeindex
 golang.org/x/tools/internal/astutil
 golang.org/x/tools/internal/bisect
@@ -131,9 +136,11 @@ golang.org/x/tools/internal/diff
 golang.org/x/tools/internal/diff/lcs
 golang.org/x/tools/internal/facts
 golang.org/x/tools/internal/fmtstr
+golang.org/x/tools/internal/goplsexport
 golang.org/x/tools/internal/moreiters
 golang.org/x/tools/internal/packagepath
 golang.org/x/tools/internal/refactor
+golang.org/x/tools/internal/refactor/inline
 golang.org/x/tools/internal/stdlib
 golang.org/x/tools/internal/typeparams
 golang.org/x/tools/internal/typesinternal
diff --git a/src/cmd/vet/vet_test.go b/src/cmd/vet/vet_test.go
index 0d509de528f247..1f2d6925ad4913 100644
--- a/src/cmd/vet/vet_test.go
+++ b/src/cmd/vet/vet_test.go
@@ -4,6 +4,10 @@
 
 package main
 
+// TODO(adonovan): replace this test by a script test
+// in cmd/go/testdata/script/vet_suite.txt like we do
+// for 'go fix'.
+
 import (
 	"bytes"
 	"errors"

From 4ad5585c2c2dc3e4387c10c297669c57449156c9 Mon Sep 17 00:00:00 2001
From: qmuntal 
Date: Wed, 8 Oct 2025 16:21:21 +0200
Subject: [PATCH 174/229] runtime: fix _rt0_ppc64x_lib on aix

CL 706395 refactored the ppc64 library entry point and missed some
important aix-specific characteristics:

- _rt0_ppc64x_lib should account for the function descriptor when
getting the callback pointer.

- _rt0_ppc64x_lib should only call _cgo_sys_thread_create when
built as a c-archive.

Fixes #75801

Cq-Include-Trybots: luci.golang.try:gotip-linux-ppc64_power10
Change-Id: I343ca09d3b9688ffa585668a6c52f0ad519d6203
Reviewed-on: https://go-review.googlesource.com/c/go/+/710175
Reviewed-by: Paul Murphy 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Pratt 
Reviewed-by: Dmitri Shuralyov 
---
 src/runtime/asm_ppc64x.s | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index 88d03dcc72c1e6..127010ef971398 100644
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -14,8 +14,14 @@
 // This is called using the host ABI. argc and argv arguments
 // should be in R3 and R4 respectively.
 TEXT _rt0_ppc64x_lib(SB),NOSPLIT|NOFRAME,$0
-	// Convert to Go ABI, and Allocate argument storage for call to newosproc0.
-	STACK_AND_SAVE_HOST_TO_GO_ABI(16)
+	// Start with standard C stack frame layout and linkage, allocate
+	// 16 bytes of argument space, save callee-save regs, and set R0 to $0.
+	// Allocate an extra 16 bytes to account for the larger fixed frame size
+	// of aix/elfv1 (48 vs 32) to ensure 16 bytes of parameter save space.
+	STACK_AND_SAVE_HOST_TO_GO_ABI(32)
+	// The above will not preserve R2 (TOC). Save it in case Go is
+	// compiled without a TOC pointer (e.g -buildmode=default).
+	MOVD	R2, 24(R1)
 
 	MOVD	R3, _rt0_ppc64x_lib_argc<>(SB)
 	MOVD	R4, _rt0_ppc64x_lib_argv<>(SB)
@@ -28,14 +34,28 @@ TEXT _rt0_ppc64x_lib(SB),NOSPLIT|NOFRAME,$0
 	MOVD	R12, CTR
 	BL	(CTR)
 
+#ifdef GOOS_aix
+	// See runtime/cgo/gcc_aix_ppc64.c
+	MOVBZ	runtime·isarchive(SB), R3	// Check buildmode = c-archive
+	CMP		$0, R3
+	BEQ		done
+#endif
+
 	// Create a new thread to do the runtime initialization and return.
+	// _cgo_sys_thread_create is a C function.
 	MOVD	_cgo_sys_thread_create(SB), R12
 	CMP	$0, R12
 	BEQ	nocgo
 	MOVD	$_rt0_ppc64x_lib_go(SB), R3
 	MOVD	$0, R4
+#ifdef GO_PPC64X_HAS_FUNCDESC
+	// Load the real entry address from the first slot of the function descriptor.
+	MOVD	8(R12), R2
+	MOVD	(R12), R12
+#endif
 	MOVD	R12, CTR
 	BL	(CTR)
+	MOVD	24(R1), R2 // Restore the old frame, and R2.
 	BR	done
 
 nocgo:
@@ -48,7 +68,7 @@ nocgo:
 	BL	(CTR)
 
 done:
-	UNSTACK_AND_RESTORE_GO_TO_HOST_ABI(16)
+	UNSTACK_AND_RESTORE_GO_TO_HOST_ABI(32)
 	RET
 
 #ifdef GO_PPC64X_HAS_FUNCDESC

From 3e43f48cb6311c3c459f5c7aa69ae7d28b7fc821 Mon Sep 17 00:00:00 2001
From: apocelipes 
Date: Mon, 20 Oct 2025 10:15:42 +0000
Subject: [PATCH 175/229] encoding/asn1: use reflect.TypeAssert to improve
 performance
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Use "reflect.TypeAssert" can gain some performance improvements:

goos: darwin
goarch: arm64
pkg: encoding/asn1
cpu: Apple M4
                          │     old     │                new                 │
                          │   sec/op    │   sec/op     vs base               │
ObjectIdentifierString-10   51.48n ± 1%   49.72n ± 2%  -3.41% (p=0.000 n=10)
Marshal-10                  7.549µ ± 0%   7.466µ ± 1%  -1.10% (p=0.000 n=10)
Unmarshal-10                1.808µ ± 0%   1.798µ ± 0%  -0.58% (p=0.000 n=10)
geomean                     889.0n        873.8n       -1.70%

                          │     old      │                  new                  │
                          │     B/op     │     B/op      vs base                 │
ObjectIdentifierString-10     32.00 ± 0%     32.00 ± 0%       ~ (p=1.000 n=10) ¹
Marshal-10                  7.336Ki ± 0%   7.336Ki ± 0%       ~ (p=1.000 n=10) ¹
Unmarshal-10                  432.0 ± 0%     432.0 ± 0%       ~ (p=1.000 n=10) ¹
geomean                       470.0          470.0       +0.00%
¹ all samples are equal

                          │    old     │                 new                 │
                          │ allocs/op  │ allocs/op   vs base                 │
ObjectIdentifierString-10   1.000 ± 0%   1.000 ± 0%       ~ (p=1.000 n=10) ¹
Marshal-10                  271.0 ± 0%   271.0 ± 0%       ~ (p=1.000 n=10) ¹
Unmarshal-10                24.00 ± 0%   24.00 ± 0%       ~ (p=1.000 n=10) ¹
geomean                     18.67        18.67       +0.00%
¹ all samples are equal

Updates #62121

Change-Id: I139b9d0c729c36018d4e00216ab6fc8388f3b51b
GitHub-Last-Rev: c87aae53727dd151fadf60f6d0089d7f6a805005
GitHub-Pull-Request: golang/go#75825
Reviewed-on: https://go-review.googlesource.com/c/go/+/710555
Reviewed-by: Roland Shoemaker 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
Auto-Submit: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
---
 src/encoding/asn1/marshal.go | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/encoding/asn1/marshal.go b/src/encoding/asn1/marshal.go
index 70e4fafc123ce1..ddb3bd85dd618d 100644
--- a/src/encoding/asn1/marshal.go
+++ b/src/encoding/asn1/marshal.go
@@ -460,17 +460,20 @@ func makeBody(value reflect.Value, params fieldParameters) (e encoder, err error
 	case flagType:
 		return bytesEncoder(nil), nil
 	case timeType:
-		t := value.Interface().(time.Time)
+		t, _ := reflect.TypeAssert[time.Time](value)
 		if params.timeType == TagGeneralizedTime || outsideUTCRange(t) {
 			return makeGeneralizedTime(t)
 		}
 		return makeUTCTime(t)
 	case bitStringType:
-		return bitStringEncoder(value.Interface().(BitString)), nil
+		v, _ := reflect.TypeAssert[BitString](value)
+		return bitStringEncoder(v), nil
 	case objectIdentifierType:
-		return makeObjectIdentifier(value.Interface().(ObjectIdentifier))
+		v, _ := reflect.TypeAssert[ObjectIdentifier](value)
+		return makeObjectIdentifier(v)
 	case bigIntType:
-		return makeBigInt(value.Interface().(*big.Int))
+		v, _ := reflect.TypeAssert[*big.Int](value)
+		return makeBigInt(v)
 	}
 
 	switch v := value; v.Kind() {
@@ -605,7 +608,7 @@ func makeField(v reflect.Value, params fieldParameters) (e encoder, err error) {
 	}
 
 	if v.Type() == rawValueType {
-		rv := v.Interface().(RawValue)
+		rv, _ := reflect.TypeAssert[RawValue](v)
 		if len(rv.FullBytes) != 0 {
 			return bytesEncoder(rv.FullBytes), nil
 		}
@@ -650,7 +653,8 @@ func makeField(v reflect.Value, params fieldParameters) (e encoder, err error) {
 			tag = params.stringType
 		}
 	case TagUTCTime:
-		if params.timeType == TagGeneralizedTime || outsideUTCRange(v.Interface().(time.Time)) {
+		t, _ := reflect.TypeAssert[time.Time](v)
+		if params.timeType == TagGeneralizedTime || outsideUTCRange(t) {
 			tag = TagGeneralizedTime
 		}
 	}

From 8d0bef7ffe5c471684f6a46f579fc7b87a46adb8 Mon Sep 17 00:00:00 2001
From: Michael Pratt 
Date: Thu, 29 Aug 2024 15:50:47 -0400
Subject: [PATCH 176/229] runtime: add linkname documentation and guidance

Explanation of the different types of linkname and guidance on the
preferred form. Written for myself, as I can never remember the guidance
and always rederive this from first principles.

Change-Id: If10cb8fc87782e25526ad597569e3c526ee33a1f
Reviewed-on: https://go-review.googlesource.com/c/go/+/609715
Reviewed-by: Cherry Mui 
Auto-Submit: Michael Pratt 
TryBot-Bypass: Michael Pratt 
---
 src/runtime/HACKING.md | 147 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 147 insertions(+)

diff --git a/src/runtime/HACKING.md b/src/runtime/HACKING.md
index 141fae9914afd5..c53779a5882f4c 100644
--- a/src/runtime/HACKING.md
+++ b/src/runtime/HACKING.md
@@ -266,6 +266,153 @@ If memory is already in a type-safe state and is simply being set to
 the zero value, this must be done using regular writes, `typedmemclr`,
 or `memclrHasPointers`. This performs write barriers.
 
+Linkname conventions
+====================
+
+```
+//go:linkname localname [importpath.name]
+```
+
+`//go:linkname` specifies the symbol name (`importpath.name`) used to a
+reference a local identifier (`localname`). The target symbol name is an
+arbitrary ELF/macho/etc symbol name, but by convention we typically use a
+package-prefixed symbol name to keep things organized.
+
+The full generality of `//go:linkname` is very flexible, so as a convention to
+simplify things, we define three standard forms of `//go:linkname` directives.
+
+When possible, always prefer to use the linkname "handshake" described below.
+
+"Push linkname"
+---------------
+
+A "push" linkname gives a local _definition_ a final symbol name in a different
+package. This effectively "pushes" the symbol to the other package.
+
+```
+//go:linkname foo otherpkg.foo
+func foo() {
+    // impl
+}
+```
+
+The other package needs a _declaration_ to use the symbol from Go, or it can
+directly reference the symbol in assembly. Typically this is an "export
+linkname" declaration (below).
+
+"Pull linkname"
+---------------
+
+A "pull" linkname gives references to a local _declaration_ a final symbol name
+in a different package. This effectively "pulls" the symbol from the other
+package.
+
+```
+//go:linkname foo otherpkg.foo
+func foo()
+```
+
+The other package simply needs to define the symbol, but typically this is a
+"export linkname" definition (below).
+
+"Export linkname"
+-----------------
+
+The second argument to `//go:linkname` is the target symbol name. If it is
+omitted, the toolchain uses the default symbol name. In other words, this is a
+linkname to itself. This seems to be a no-op, but it is used to mean that this
+symbol is "exported" for use with another linkname.
+
+```
+//go:linkname foo
+func foo() {
+    // impl
+}
+```
+
+When applied to a definition, an export linkname indicates that another package
+has a pull linkname targeting this symbol. This has a few effects:
+
+- The compiler avoids generates ABI wrappers for ABI0 and/or ABIInternal, so a
+  symbol defined in Go can be referenced from assembly in another package, or
+  vice versa.
+- The linker will allow pull linknames to this symbol even with
+  `-checklinkname=true` (see "Handshake" section below).
+
+```
+//go:linkname foo
+func foo()
+```
+
+When applied to a declaration, an export linkname indicates that another package
+has a push linkname targeting this symbol. Other than documentation, the only
+effect this has on the toolchain is that the compiler will not require a `.s`
+file in the package (normally the compiler requires a `.s` file when there are
+function declarations without a body).
+
+Handshake
+---------
+
+We always prefer to use push linknames rather than pull linknames. With a push
+linkname, the package with the definition is aware it is publishing an API to
+another package. On the other hand, with a pull linkname, the definition
+package may be completely unaware of the dependency and may unintentionally
+break users.
+
+The preferred form for a linkname is to use a push linkname in the defining
+package, and a target linkname in the receiving package. The latter is not
+strictly required, but serves as documentation. By convention, the receiving
+package names the symbol containing the source package to further aid
+documentation.
+
+```
+package runtime
+
+//go:linkname foo otherpkg.runtime_foo
+func foo() {
+    // impl
+}
+```
+
+```
+package otherpkg
+
+//go:linkname runtime_foo
+func runtime_foo()
+```
+
+As of Go 1.23, the linker forbids pull linknames of symbols in the standard
+library unless they participate in a handshake. Since many third-party packages
+already have pull linknames to standard library functions, for backwards
+compatibility, standard library symbols that are the target of external pull
+linknames must use a target linkname to signal to the linker that pull
+linknames are acceptable.
+
+```
+package runtime
+
+//go:linkname fastrand
+func fastrand() {
+    // impl
+}
+```
+
+Note that linker enforcement can be disabled with the `-checklinkname=false`
+flag.
+
+Variables
+---------
+
+All of the examples above use `//go:linkname` on functions. It is also possible
+to use it on global variables as well, though this is much less common.
+
+Variables don't have a clear distinction between definition and declaration. As
+a rule, only one side should have a non-zero initial value. That side is the
+"definition" and the other is the "declaration".
+
+Both sides should have the same type, including size. Though if one side is
+larger than another, the linker allocates space for the larger size.
+
 Runtime-only compiler directives
 ================================
 

From 58a8fdb6cf4a905fd3de44bf2dd87d14fbd38dfe Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 1 Oct 2025 23:01:55 -0400
Subject: [PATCH 177/229] cmd/go: inject State parameter into `bug.runBug`

This command modifies the call tree starting at `bug.runBug` to inject
a `State` parameter to every function that is currently using the
global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/bug
rf 'inject modload.LoaderState runBug'
cd ..
./rf-cleanup.zsh

Change-Id: Idf87733f586a8aae0779132f54a8d988e2551bae
Reviewed-on: https://go-review.googlesource.com/c/go/+/709982
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/bug/bug.go      | 10 +++++-----
 src/cmd/go/internal/envcmd/env.go   | 16 ++++++++--------
 src/cmd/go/internal/modcmd/edit.go  |  2 +-
 src/cmd/go/internal/modget/get.go   |  4 ++--
 src/cmd/go/internal/modload/init.go | 12 ++++++------
 5 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/src/cmd/go/internal/bug/bug.go b/src/cmd/go/internal/bug/bug.go
index 4e9ae1e9b499ca..ccd8dee95e69b3 100644
--- a/src/cmd/go/internal/bug/bug.go
+++ b/src/cmd/go/internal/bug/bug.go
@@ -51,7 +51,7 @@ func runBug(ctx context.Context, cmd *base.Command, args []string) {
 	buf.WriteString(bugHeader)
 	printGoVersion(&buf)
 	buf.WriteString("### Does this issue reproduce with the latest release?\n\n\n")
-	printEnvDetails(&buf)
+	printEnvDetails(modload.LoaderState, &buf)
 	buf.WriteString(bugFooter)
 
 	body := buf.String()
@@ -92,20 +92,20 @@ func printGoVersion(w io.Writer) {
 	fmt.Fprintf(w, "\n")
 }
 
-func printEnvDetails(w io.Writer) {
+func printEnvDetails(loaderstate *modload.State, w io.Writer) {
 	fmt.Fprintf(w, "### What operating system and processor architecture are you using (`go env`)?\n\n")
 	fmt.Fprintf(w, "
    go env Output
    \n")
 	fmt.Fprintf(w, "$ go env\n")
-	printGoEnv(w)
+	printGoEnv(loaderstate, w)
 	printGoDetails(w)
 	printOSDetails(w)
 	printCDetails(w)
 	fmt.Fprintf(w, "
    \n\n")
 }
 
-func printGoEnv(w io.Writer) {
+func printGoEnv(loaderstate *modload.State, w io.Writer) {
 	env := envcmd.MkEnv()
-	env = append(env, envcmd.ExtraEnvVars()...)
+	env = append(env, envcmd.ExtraEnvVars(loaderstate)...)
 	env = append(env, envcmd.ExtraEnvVarsCostly()...)
 	envcmd.PrintEnv(w, env, false)
 }
diff --git a/src/cmd/go/internal/envcmd/env.go b/src/cmd/go/internal/envcmd/env.go
index 13708ae170c1d8..517722a4265edd 100644
--- a/src/cmd/go/internal/envcmd/env.go
+++ b/src/cmd/go/internal/envcmd/env.go
@@ -189,16 +189,16 @@ func findEnv(env []cfg.EnvVar, name string) string {
 }
 
 // ExtraEnvVars returns environment variables that should not leak into child processes.
-func ExtraEnvVars() []cfg.EnvVar {
+func ExtraEnvVars(loaderstate *modload.State) []cfg.EnvVar {
 	gomod := ""
-	modload.Init(modload.LoaderState)
-	if modload.HasModRoot(modload.LoaderState) {
-		gomod = modload.ModFilePath()
-	} else if modload.Enabled(modload.LoaderState) {
+	modload.Init(loaderstate)
+	if modload.HasModRoot(loaderstate) {
+		gomod = modload.ModFilePath(loaderstate)
+	} else if modload.Enabled(loaderstate) {
 		gomod = os.DevNull
 	}
-	modload.InitWorkfile(modload.LoaderState)
-	gowork := modload.WorkFilePath(modload.LoaderState)
+	modload.InitWorkfile(loaderstate)
+	gowork := modload.WorkFilePath(loaderstate)
 	// As a special case, if a user set off explicitly, report that in GOWORK.
 	if cfg.Getenv("GOWORK") == "off" {
 		gowork = "off"
@@ -306,7 +306,7 @@ func runEnv(ctx context.Context, cmd *base.Command, args []string) {
 	}
 
 	env := cfg.CmdEnv
-	env = append(env, ExtraEnvVars()...)
+	env = append(env, ExtraEnvVars(modload.LoaderState)...)
 
 	if err := fsys.Init(); err != nil {
 		base.Fatal(err)
diff --git a/src/cmd/go/internal/modcmd/edit.go b/src/cmd/go/internal/modcmd/edit.go
index 041b4432bfd4f0..d5774e98d76cce 100644
--- a/src/cmd/go/internal/modcmd/edit.go
+++ b/src/cmd/go/internal/modcmd/edit.go
@@ -232,7 +232,7 @@ func runEdit(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) == 1 {
 		gomod = args[0]
 	} else {
-		gomod = modload.ModFilePath()
+		gomod = modload.ModFilePath(modload.LoaderState)
 	}
 
 	if *editModule != "" {
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index 141e1708fa6ded..b26406ee1d0fa2 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -768,7 +768,7 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 			// restricted to matching packages in the main module.
 			pkgPattern, mainModule := modload.LoaderState.MainModules.DirImportPath(modload.LoaderState, ctx, q.pattern)
 			if pkgPattern == "." {
-				modload.MustHaveModRoot()
+				modload.MustHaveModRoot(modload.LoaderState)
 				versions := modload.LoaderState.MainModules.Versions()
 				modRoots := make([]string, 0, len(versions))
 				for _, m := range versions {
@@ -791,7 +791,7 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 					return errSet(fmt.Errorf("no package to get in current directory"))
 				}
 				if !q.isWildcard() {
-					modload.MustHaveModRoot()
+					modload.MustHaveModRoot(modload.LoaderState)
 					return errSet(fmt.Errorf("%s%s is not a package in module rooted at %s", q.pattern, absDetail, modload.LoaderState.MainModules.ModRoot(mainModule)))
 				}
 				search.WarnUnmatched([]*search.Match{match})
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 20751528862ce2..383ea20e3e673a 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -661,18 +661,18 @@ func HasModRoot(loaderstate *State) bool {
 
 // MustHaveModRoot checks that a main module or main modules are present,
 // and calls base.Fatalf if there are no main modules.
-func MustHaveModRoot() {
-	Init(LoaderState)
-	if !HasModRoot(LoaderState) {
-		die(LoaderState)
+func MustHaveModRoot(loaderstate *State) {
+	Init(loaderstate)
+	if !HasModRoot(loaderstate) {
+		die(loaderstate)
 	}
 }
 
 // ModFilePath returns the path that would be used for the go.mod
 // file, if in module mode. ModFilePath calls base.Fatalf if there is no main
 // module, even if -modfile is set.
-func ModFilePath() string {
-	MustHaveModRoot()
+func ModFilePath(loaderstate *State) string {
+	MustHaveModRoot(loaderstate)
 	return modFilePath(findModuleRoot(base.Cwd()))
 }
 

From f7eaea02fd8a5d1d37f023a1144e747da0b3dd7b Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 8 Oct 2025 12:07:44 -0400
Subject: [PATCH 178/229] cmd/go: inject state parameter into `clean.runClean`

This command modifies the call tree starting at `clean.runClean` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/clean
rf '
  inject modload.LoaderState runClean
  add clean.go var moduleLoaderState *modload.State
  ex {
    import "cmd/go/internal/modload";
    modload.LoaderState -> moduleLoaderState
  }
  add runClean://+0 moduleLoaderState := modload.NewState()
  rm clean.go:/var moduleLoaderState \*modload.State/
'
cd ..
./rf-cleanup.zsh

Change-Id: I2e30e44cfff7e533801dabd7159fa760ac6bb824
Reviewed-on: https://go-review.googlesource.com/c/go/+/710296
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/clean/clean.go | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/cmd/go/internal/clean/clean.go b/src/cmd/go/internal/clean/clean.go
index 1c05977de554f8..ae744e13bc79b5 100644
--- a/src/cmd/go/internal/clean/clean.go
+++ b/src/cmd/go/internal/clean/clean.go
@@ -120,7 +120,8 @@ func init() {
 }
 
 func runClean(ctx context.Context, cmd *base.Command, args []string) {
-	modload.InitWorkfile(modload.LoaderState)
+	moduleLoaderState := modload.NewState()
+	modload.InitWorkfile(moduleLoaderState)
 	if len(args) > 0 {
 		cacheFlag := ""
 		switch {
@@ -142,13 +143,13 @@ func runClean(ctx context.Context, cmd *base.Command, args []string) {
 	// either the flags and arguments explicitly imply a package,
 	// or no other target (such as a cache) was requested to be cleaned.
 	cleanPkg := len(args) > 0 || cleanI || cleanR
-	if (!modload.Enabled(modload.LoaderState) || modload.HasModRoot(modload.LoaderState)) &&
+	if (!modload.Enabled(moduleLoaderState) || modload.HasModRoot(moduleLoaderState)) &&
 		!cleanCache && !cleanModcache && !cleanTestcache && !cleanFuzzcache {
 		cleanPkg = true
 	}
 
 	if cleanPkg {
-		for _, pkg := range load.PackagesAndErrors(modload.LoaderState, ctx, load.PackageOpts{}, args) {
+		for _, pkg := range load.PackagesAndErrors(moduleLoaderState, ctx, load.PackageOpts{}, args) {
 			clean(pkg)
 		}
 	}

From 29a81624f744f0435925cb7c349f68c86213f09c Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Fri, 3 Oct 2025 15:04:30 -0400
Subject: [PATCH 179/229] cmd/go: inject state parameter into `fmtcmd.runFmt`

This command modifies the call tree starting at `fmtcmd.runFmt` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/fmtcmd
rf '
  inject modload.LoaderState runFmt
  add fmt.go var moduleLoaderState *modload.State
  ex {
    import "cmd/go/internal/modload";
    modload.LoaderState -> moduleLoaderState
  }
  add runFmt://+0 moduleLoaderState := modload.NewState()
  rm fmt.go:/var moduleLoaderState \*modload.State/
'
cd ..
./rf-cleanup.zsh

Change-Id: Ib6692aba37a2cbc5b52d3bb705ec2b442afd26eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/709989
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/fmtcmd/fmt.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/cmd/go/internal/fmtcmd/fmt.go b/src/cmd/go/internal/fmtcmd/fmt.go
index a42e7753050356..cd689b510deb19 100644
--- a/src/cmd/go/internal/fmtcmd/fmt.go
+++ b/src/cmd/go/internal/fmtcmd/fmt.go
@@ -50,6 +50,7 @@ See also: go fix, go vet.
 }
 
 func runFmt(ctx context.Context, cmd *base.Command, args []string) {
+	moduleLoaderState := modload.NewState()
 	printed := false
 	gofmt := gofmtPath()
 
@@ -59,8 +60,8 @@ func runFmt(ctx context.Context, cmd *base.Command, args []string) {
 	baseGofmtArgs := len(gofmtArgs)
 	baseGofmtArgLen := gofmtArgLen
 
-	for _, pkg := range load.PackagesAndErrors(modload.LoaderState, ctx, load.PackageOpts{}, args) {
-		if modload.Enabled(modload.LoaderState) && pkg.Module != nil && !pkg.Module.Main {
+	for _, pkg := range load.PackagesAndErrors(moduleLoaderState, ctx, load.PackageOpts{}, args) {
+		if modload.Enabled(moduleLoaderState) && pkg.Module != nil && !pkg.Module.Main {
 			if !printed {
 				fmt.Fprintf(os.Stderr, "go: not formatting packages in dependency modules\n")
 				printed = true

From 35e8309be2a8027a6c20847ab4a8eb6031fd7aeb Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Tue, 30 Sep 2025 21:40:22 -0400
Subject: [PATCH 180/229] cmd/go: inject State parameter into `list.runList`

This command modifies the call tree starting at `list.runList` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/list
rf 'inject modload.LoaderState runList'
cd ..
./rf-cleanup.zsh

Change-Id: I7274bc3dc6779bd8306fb79c158aa6f0473827a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/709979
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/list/list.go       | 16 ++++-----
 src/cmd/go/internal/load/pkg.go        |  8 ++---
 src/cmd/go/internal/load/test.go       | 16 ++++-----
 src/cmd/go/internal/modcmd/download.go |  2 +-
 src/cmd/go/internal/modcmd/vendor.go   |  2 +-
 src/cmd/go/internal/modcmd/why.go      |  2 +-
 src/cmd/go/internal/modload/build.go   | 26 +++++++--------
 src/cmd/go/internal/modload/list.go    | 46 +++++++++++++-------------
 src/cmd/go/internal/test/test.go       |  2 +-
 src/cmd/go/internal/vet/vet.go         |  2 +-
 src/cmd/go/internal/work/action.go     |  4 +--
 src/cmd/go/internal/work/build.go      |  8 ++---
 12 files changed, 67 insertions(+), 67 deletions(-)

diff --git a/src/cmd/go/internal/list/list.go b/src/cmd/go/internal/list/list.go
index 0bf86ae004a26e..454efd31947d04 100644
--- a/src/cmd/go/internal/list/list.go
+++ b/src/cmd/go/internal/list/list.go
@@ -479,7 +479,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		fm := template.FuncMap{
 			"join":    strings.Join,
 			"context": context,
-			"module":  func(path string) *modinfo.ModulePublic { return modload.ModuleInfo(ctx, path) },
+			"module":  func(path string) *modinfo.ModulePublic { return modload.ModuleInfo(modload.LoaderState, ctx, path) },
 		}
 		tmpl, err := template.New("main").Funcs(fm).Parse(*listFmt)
 		if err != nil {
@@ -569,7 +569,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		if *listReuse != "" && len(args) == 0 {
 			base.Fatalf("go: list -m -reuse only has an effect with module@version arguments")
 		}
-		mods, err := modload.ListModules(ctx, args, mode, *listReuse)
+		mods, err := modload.ListModules(modload.LoaderState, ctx, args, mode, *listReuse)
 		if !*listE {
 			for _, m := range mods {
 				if m.Error != nil {
@@ -648,10 +648,10 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 						sema.Release(1)
 						wg.Done()
 					}
-					pmain, ptest, pxtest = load.TestPackagesAndErrors(ctx, done, pkgOpts, p, nil)
+					pmain, ptest, pxtest = load.TestPackagesAndErrors(modload.LoaderState, ctx, done, pkgOpts, p, nil)
 				} else {
 					var perr *load.Package
-					pmain, ptest, pxtest, perr = load.TestPackagesFor(ctx, pkgOpts, p, nil)
+					pmain, ptest, pxtest, perr = load.TestPackagesFor(modload.LoaderState, ctx, pkgOpts, p, nil)
 					if perr != nil {
 						base.Fatalf("go: can't load test package: %s", perr.Error)
 					}
@@ -733,7 +733,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 		// TODO: Use pkgsFilter?
 		for _, p := range pkgs {
 			if len(p.GoFiles)+len(p.CgoFiles) > 0 {
-				a.Deps = append(a.Deps, b.AutoAction(work.ModeInstall, work.ModeInstall, p))
+				a.Deps = append(a.Deps, b.AutoAction(modload.LoaderState, work.ModeInstall, work.ModeInstall, p))
 			}
 		}
 		b.Do(ctx, a)
@@ -741,8 +741,8 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 
 	for _, p := range pkgs {
 		// Show vendor-expanded paths in listing
-		p.TestImports = p.Resolve(p.TestImports)
-		p.XTestImports = p.Resolve(p.XTestImports)
+		p.TestImports = p.Resolve(modload.LoaderState, p.TestImports)
+		p.XTestImports = p.Resolve(modload.LoaderState, p.XTestImports)
 		p.DepOnly = !cmdline[p]
 
 		if *listCompiled {
@@ -850,7 +850,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
 			if *listRetracted {
 				mode |= modload.ListRetracted
 			}
-			rmods, err := modload.ListModules(ctx, args, mode, *listReuse)
+			rmods, err := modload.ListModules(modload.LoaderState, ctx, args, mode, *listReuse)
 			if err != nil && !*listE {
 				base.Error(err)
 			}
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index cfaece2072dbb9..fedb313b1f5725 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -355,14 +355,14 @@ func (p *Package) setLoadPackageDataError(err error, path string, stk *ImportSta
 // can produce better error messages if it starts with the original paths.
 // The initial load of p loads all the non-test imports and rewrites
 // the vendored paths, so nothing should ever call p.vendored(p.Imports).
-func (p *Package) Resolve(imports []string) []string {
+func (p *Package) Resolve(loaderstate *modload.State, imports []string) []string {
 	if len(imports) > 0 && len(p.Imports) > 0 && &imports[0] == &p.Imports[0] {
 		panic("internal error: p.Resolve(p.Imports) called")
 	}
 	seen := make(map[string]bool)
 	var all []string
 	for _, path := range imports {
-		path = ResolveImportPath(p, path)
+		path = ResolveImportPath(loaderstate, p, path)
 		if !seen[path] {
 			seen[path] = true
 			all = append(all, path)
@@ -1151,7 +1151,7 @@ func isDir(path string) bool {
 // First, there is Go 1.5 vendoring (golang.org/s/go15vendor).
 // If vendor expansion doesn't trigger, then the path is also subject to
 // Go 1.11 module legacy conversion (golang.org/issue/25069).
-func ResolveImportPath(parent *Package, path string) (found string) {
+func ResolveImportPath(loaderstate *modload.State, parent *Package, path string) (found string) {
 	var parentPath, parentDir, parentRoot string
 	parentIsStd := false
 	if parent != nil {
@@ -1160,7 +1160,7 @@ func ResolveImportPath(parent *Package, path string) (found string) {
 		parentRoot = parent.Root
 		parentIsStd = parent.Standard
 	}
-	return resolveImportPath(modload.LoaderState, path, parentPath, parentDir, parentRoot, parentIsStd)
+	return resolveImportPath(loaderstate, path, parentPath, parentDir, parentRoot, parentIsStd)
 }
 
 func resolveImportPath(loaderstate *modload.State, path, parentPath, parentDir, parentRoot string, parentIsStd bool) (found string) {
diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
index 9019545b4b8d82..7150d1380d866a 100644
--- a/src/cmd/go/internal/load/test.go
+++ b/src/cmd/go/internal/load/test.go
@@ -48,8 +48,8 @@ type TestCover struct {
 // the package containing an error if the test packages or
 // their dependencies have errors.
 // Only test packages without errors are returned.
-func TestPackagesFor(ctx context.Context, opts PackageOpts, p *Package, cover *TestCover) (pmain, ptest, pxtest, perr *Package) {
-	pmain, ptest, pxtest = TestPackagesAndErrors(ctx, nil, opts, p, cover)
+func TestPackagesFor(loaderstate *modload.State, ctx context.Context, opts PackageOpts, p *Package, cover *TestCover) (pmain, ptest, pxtest, perr *Package) {
+	pmain, ptest, pxtest = TestPackagesAndErrors(loaderstate, ctx, nil, opts, p, cover)
 	for _, p1 := range []*Package{ptest, pxtest, pmain} {
 		if p1 == nil {
 			// pxtest may be nil
@@ -99,7 +99,7 @@ func TestPackagesFor(ctx context.Context, opts PackageOpts, p *Package, cover *T
 //
 // The caller is expected to have checked that len(p.TestGoFiles)+len(p.XTestGoFiles) > 0,
 // or else there's no point in any of this.
-func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p *Package, cover *TestCover) (pmain, ptest, pxtest *Package) {
+func TestPackagesAndErrors(loaderstate *modload.State, ctx context.Context, done func(), opts PackageOpts, p *Package, cover *TestCover) (pmain, ptest, pxtest *Package) {
 	ctx, span := trace.StartSpan(ctx, "load.TestPackagesAndErrors")
 	defer span.Done()
 
@@ -107,7 +107,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 	defer pre.flush()
 	allImports := append([]string{}, p.TestImports...)
 	allImports = append(allImports, p.XTestImports...)
-	pre.preloadImports(modload.LoaderState, ctx, opts, allImports, p.Internal.Build)
+	pre.preloadImports(loaderstate, ctx, opts, allImports, p.Internal.Build)
 
 	var ptestErr, pxtestErr *PackageError
 	var imports, ximports []*Package
@@ -117,7 +117,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 	stk.Push(ImportInfo{Pkg: p.ImportPath + " (test)"})
 	rawTestImports := str.StringList(p.TestImports)
 	for i, path := range p.TestImports {
-		p1, err := loadImport(modload.LoaderState, ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.TestImportPos[path], ResolveImport)
+		p1, err := loadImport(loaderstate, ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.TestImportPos[path], ResolveImport)
 		if err != nil && ptestErr == nil {
 			ptestErr = err
 			incomplete = true
@@ -146,7 +146,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 	var pxtestIncomplete bool
 	rawXTestImports := str.StringList(p.XTestImports)
 	for i, path := range p.XTestImports {
-		p1, err := loadImport(modload.LoaderState, ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.XTestImportPos[path], ResolveImport)
+		p1, err := loadImport(loaderstate, ctx, opts, pre, path, p.Dir, p, &stk, p.Internal.Build.XTestImportPos[path], ResolveImport)
 		if err != nil && pxtestErr == nil {
 			pxtestErr = err
 		}
@@ -293,7 +293,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 	}
 
 	pb := p.Internal.Build
-	pmain.DefaultGODEBUG = defaultGODEBUG(modload.LoaderState, pmain, pb.Directives, pb.TestDirectives, pb.XTestDirectives)
+	pmain.DefaultGODEBUG = defaultGODEBUG(loaderstate, pmain, pb.Directives, pb.TestDirectives, pb.XTestDirectives)
 	if pmain.Internal.BuildInfo == nil || pmain.DefaultGODEBUG != p.DefaultGODEBUG {
 		// Either we didn't generate build info for the package under test (because it wasn't package main), or
 		// the DefaultGODEBUG used to build the test main package is different from the DefaultGODEBUG
@@ -322,7 +322,7 @@ func TestPackagesAndErrors(ctx context.Context, done func(), opts PackageOpts, p
 		if dep == ptest.ImportPath {
 			pmain.Internal.Imports = append(pmain.Internal.Imports, ptest)
 		} else {
-			p1, err := loadImport(modload.LoaderState, ctx, opts, pre, dep, "", nil, &stk, nil, 0)
+			p1, err := loadImport(loaderstate, ctx, opts, pre, dep, "", nil, &stk, nil, 0)
 			if err != nil && pmain.Error == nil {
 				pmain.Error = err
 				pmain.Incomplete = true
diff --git a/src/cmd/go/internal/modcmd/download.go b/src/cmd/go/internal/modcmd/download.go
index f4ed4b45834e89..e5e0e927b04ebe 100644
--- a/src/cmd/go/internal/modcmd/download.go
+++ b/src/cmd/go/internal/modcmd/download.go
@@ -184,7 +184,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	var mods []*ModuleJSON
 	type token struct{}
 	sem := make(chan token, runtime.GOMAXPROCS(0))
-	infos, infosErr := modload.ListModules(ctx, args, 0, *downloadReuse)
+	infos, infosErr := modload.ListModules(modload.LoaderState, ctx, args, 0, *downloadReuse)
 
 	// There is a bit of a chicken-and-egg problem here: ideally we need to know
 	// which Go version to switch to download the requested modules, but if we
diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index 8d9672d5365523..45d0aeff9c36de 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -169,7 +169,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 
 		goVersion := ""
 		if includeGoVersions {
-			goVersion = modload.ModuleInfo(ctx, m.Path).GoVersion
+			goVersion = modload.ModuleInfo(modload.LoaderState, ctx, m.Path).GoVersion
 		}
 		switch {
 		case isExplicit[m] && goVersion != "":
diff --git a/src/cmd/go/internal/modcmd/why.go b/src/cmd/go/internal/modcmd/why.go
index b37d9fded0f47c..d0ec2444653f22 100644
--- a/src/cmd/go/internal/modcmd/why.go
+++ b/src/cmd/go/internal/modcmd/why.go
@@ -83,7 +83,7 @@ func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 			}
 		}
 
-		mods, err := modload.ListModules(ctx, args, 0, "")
+		mods, err := modload.ListModules(modload.LoaderState, ctx, args, 0, "")
 		if err != nil {
 			base.Fatal(err)
 		}
diff --git a/src/cmd/go/internal/modload/build.go b/src/cmd/go/internal/modload/build.go
index 5b1b643d272dfd..0773a277990649 100644
--- a/src/cmd/go/internal/modload/build.go
+++ b/src/cmd/go/internal/modload/build.go
@@ -83,27 +83,27 @@ func PackageModRoot(loaderstate *State, ctx context.Context, pkgpath string) str
 	return root
 }
 
-func ModuleInfo(ctx context.Context, path string) *modinfo.ModulePublic {
-	if !Enabled(LoaderState) {
+func ModuleInfo(loaderstate *State, ctx context.Context, path string) *modinfo.ModulePublic {
+	if !Enabled(loaderstate) {
 		return nil
 	}
 
 	if path, vers, found := strings.Cut(path, "@"); found {
 		m := module.Version{Path: path, Version: vers}
-		return moduleInfo(LoaderState, ctx, nil, m, 0, nil)
+		return moduleInfo(loaderstate, ctx, nil, m, 0, nil)
 	}
 
-	rs := LoadModFile(LoaderState, ctx)
+	rs := LoadModFile(loaderstate, ctx)
 
 	var (
 		v  string
 		ok bool
 	)
 	if rs.pruning == pruned {
-		v, ok = rs.rootSelected(LoaderState, path)
+		v, ok = rs.rootSelected(loaderstate, path)
 	}
 	if !ok {
-		mg, err := rs.Graph(LoaderState, ctx)
+		mg, err := rs.Graph(loaderstate, ctx)
 		if err != nil {
 			base.Fatal(err)
 		}
@@ -119,16 +119,16 @@ func ModuleInfo(ctx context.Context, path string) *modinfo.ModulePublic {
 		}
 	}
 
-	return moduleInfo(LoaderState, ctx, rs, module.Version{Path: path, Version: v}, 0, nil)
+	return moduleInfo(loaderstate, ctx, rs, module.Version{Path: path, Version: v}, 0, nil)
 }
 
 // addUpdate fills in m.Update if an updated version is available.
-func addUpdate(ctx context.Context, m *modinfo.ModulePublic) {
+func addUpdate(loaderstate *State, ctx context.Context, m *modinfo.ModulePublic) {
 	if m.Version == "" {
 		return
 	}
 
-	info, err := Query(LoaderState, ctx, m.Path, "upgrade", m.Version, CheckAllowed)
+	info, err := Query(loaderstate, ctx, m.Path, "upgrade", m.Version, CheckAllowed)
 	if _, ok := errors.AsType[*NoMatchingVersionError](err); ok ||
 		errors.Is(err, fs.ErrNotExist) ||
 		errors.Is(err, ErrDisallowed) {
@@ -212,7 +212,7 @@ func mergeOrigin(m1, m2 *codehost.Origin) *codehost.Origin {
 // addVersions fills in m.Versions with the list of known versions.
 // Excluded versions will be omitted. If listRetracted is false, retracted
 // versions will also be omitted.
-func addVersions(ctx context.Context, m *modinfo.ModulePublic, listRetracted bool) {
+func addVersions(loaderstate *State, ctx context.Context, m *modinfo.ModulePublic, listRetracted bool) {
 	// TODO(bcmills): Would it make sense to check for reuse here too?
 	// Perhaps that doesn't buy us much, though: we would always have to fetch
 	// all of the version tags to list the available versions anyway.
@@ -221,7 +221,7 @@ func addVersions(ctx context.Context, m *modinfo.ModulePublic, listRetracted boo
 	if listRetracted {
 		allowed = CheckExclusions
 	}
-	v, origin, err := versions(LoaderState, ctx, m.Path, allowed)
+	v, origin, err := versions(loaderstate, ctx, m.Path, allowed)
 	if err != nil && m.Error == nil {
 		m.Error = &modinfo.ModuleError{Err: err.Error()}
 	}
@@ -262,8 +262,8 @@ func addRetraction(loaderstate *State, ctx context.Context, m *modinfo.ModulePub
 
 // addDeprecation fills in m.Deprecated if the module was deprecated by its
 // author. m.Error is set if there's an error loading deprecation information.
-func addDeprecation(ctx context.Context, m *modinfo.ModulePublic) {
-	deprecation, err := CheckDeprecation(LoaderState, ctx, module.Version{Path: m.Path, Version: m.Version})
+func addDeprecation(loaderstate *State, ctx context.Context, m *modinfo.ModulePublic) {
+	deprecation, err := CheckDeprecation(loaderstate, ctx, module.Version{Path: m.Path, Version: m.Version})
 	if _, ok := errors.AsType[*NoMatchingVersionError](err); ok || errors.Is(err, fs.ErrNotExist) {
 		// Ignore "no matching version" and "not found" errors.
 		// This means the proxy has no matching version or no versions at all.
diff --git a/src/cmd/go/internal/modload/list.go b/src/cmd/go/internal/modload/list.go
index bd28d7596e160a..21057f5c1ecad0 100644
--- a/src/cmd/go/internal/modload/list.go
+++ b/src/cmd/go/internal/modload/list.go
@@ -41,7 +41,7 @@ const (
 // along with any error preventing additional matches from being identified.
 //
 // The returned slice can be nonempty even if the error is non-nil.
-func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile string) ([]*modinfo.ModulePublic, error) {
+func ListModules(loaderstate *State, ctx context.Context, args []string, mode ListMode, reuseFile string) ([]*modinfo.ModulePublic, error) {
 	var reuse map[module.Version]*modinfo.ModulePublic
 	if reuseFile != "" {
 		data, err := os.ReadFile(reuseFile)
@@ -69,7 +69,7 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 		}
 	}
 
-	rs, mods, err := listModules(ctx, LoadModFile(LoaderState, ctx), args, mode, reuse)
+	rs, mods, err := listModules(loaderstate, ctx, LoadModFile(loaderstate, ctx), args, mode, reuse)
 
 	type token struct{}
 	sem := make(chan token, runtime.GOMAXPROCS(0))
@@ -82,16 +82,16 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 				sem <- token{}
 				go func() {
 					if mode&ListU != 0 {
-						addUpdate(ctx, m)
+						addUpdate(loaderstate, ctx, m)
 					}
 					if mode&ListVersions != 0 {
-						addVersions(ctx, m, mode&ListRetractedVersions != 0)
+						addVersions(loaderstate, ctx, m, mode&ListRetractedVersions != 0)
 					}
 					if mode&ListRetracted != 0 {
-						addRetraction(LoaderState, ctx, m)
+						addRetraction(loaderstate, ctx, m)
 					}
 					if mode&ListDeprecated != 0 {
-						addDeprecation(ctx, m)
+						addDeprecation(loaderstate, ctx, m)
 					}
 					<-sem
 				}()
@@ -109,7 +109,7 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 	}
 
 	if err == nil {
-		LoaderState.requirements = rs
+		loaderstate.requirements = rs
 		// TODO(#61605): The extra ListU clause fixes a problem with Go 1.21rc3
 		// where "go mod tidy" and "go list -m -u all" fight over whether the go.sum
 		// should be considered up-to-date. The fix for now is to always treat the
@@ -117,20 +117,20 @@ func ListModules(ctx context.Context, args []string, mode ListMode, reuseFile st
 		// but in general list -u is looking up other checksums in the checksum database
 		// that won't be necessary later, so it makes sense not to write the go.sum back out.
 		if !ExplicitWriteGoMod && mode&ListU == 0 {
-			err = commitRequirements(LoaderState, ctx, WriteOpts{})
+			err = commitRequirements(loaderstate, ctx, WriteOpts{})
 		}
 	}
 	return mods, err
 }
 
-func listModules(ctx context.Context, rs *Requirements, args []string, mode ListMode, reuse map[module.Version]*modinfo.ModulePublic) (_ *Requirements, mods []*modinfo.ModulePublic, mgErr error) {
+func listModules(loaderstate *State, ctx context.Context, rs *Requirements, args []string, mode ListMode, reuse map[module.Version]*modinfo.ModulePublic) (_ *Requirements, mods []*modinfo.ModulePublic, mgErr error) {
 	if len(args) == 0 {
 		var ms []*modinfo.ModulePublic
-		for _, m := range LoaderState.MainModules.Versions() {
+		for _, m := range loaderstate.MainModules.Versions() {
 			if gover.IsToolchain(m.Path) {
 				continue
 			}
-			ms = append(ms, moduleInfo(LoaderState, ctx, rs, m, mode, reuse))
+			ms = append(ms, moduleInfo(loaderstate, ctx, rs, m, mode, reuse))
 		}
 		return rs, ms, nil
 	}
@@ -145,25 +145,25 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 		}
 		if arg == "all" || strings.Contains(arg, "...") {
 			needFullGraph = true
-			if !HasModRoot(LoaderState) {
+			if !HasModRoot(loaderstate) {
 				base.Fatalf("go: cannot match %q: %v", arg, ErrNoModRoot)
 			}
 			continue
 		}
 		if path, vers, found := strings.Cut(arg, "@"); found {
 			if vers == "upgrade" || vers == "patch" {
-				if _, ok := rs.rootSelected(LoaderState, path); !ok || rs.pruning == unpruned {
+				if _, ok := rs.rootSelected(loaderstate, path); !ok || rs.pruning == unpruned {
 					needFullGraph = true
-					if !HasModRoot(LoaderState) {
+					if !HasModRoot(loaderstate) {
 						base.Fatalf("go: cannot match %q: %v", arg, ErrNoModRoot)
 					}
 				}
 			}
 			continue
 		}
-		if _, ok := rs.rootSelected(LoaderState, arg); !ok || rs.pruning == unpruned {
+		if _, ok := rs.rootSelected(loaderstate, arg); !ok || rs.pruning == unpruned {
 			needFullGraph = true
-			if mode&ListVersions == 0 && !HasModRoot(LoaderState) {
+			if mode&ListVersions == 0 && !HasModRoot(loaderstate) {
 				base.Fatalf("go: cannot match %q without -versions or an explicit version: %v", arg, ErrNoModRoot)
 			}
 		}
@@ -171,7 +171,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 
 	var mg *ModuleGraph
 	if needFullGraph {
-		rs, mg, mgErr = expandGraph(LoaderState, ctx, rs)
+		rs, mg, mgErr = expandGraph(loaderstate, ctx, rs)
 	}
 
 	matchedModule := map[module.Version]bool{}
@@ -179,7 +179,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 		if path, vers, found := strings.Cut(arg, "@"); found {
 			var current string
 			if mg == nil {
-				current, _ = rs.rootSelected(LoaderState, path)
+				current, _ = rs.rootSelected(loaderstate, path)
 			} else {
 				current = mg.Selected(path)
 			}
@@ -198,7 +198,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 				// specific revision or used 'go list -retracted'.
 				allowed = nil
 			}
-			info, err := queryReuse(LoaderState, ctx, path, vers, current, allowed, reuse)
+			info, err := queryReuse(loaderstate, ctx, path, vers, current, allowed, reuse)
 			if err != nil {
 				var origin *codehost.Origin
 				if info != nil {
@@ -217,7 +217,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 			// *Requirements instead.
 			var noRS *Requirements
 
-			mod := moduleInfo(LoaderState, ctx, noRS, module.Version{Path: path, Version: info.Version}, mode, reuse)
+			mod := moduleInfo(loaderstate, ctx, noRS, module.Version{Path: path, Version: info.Version}, mode, reuse)
 			if vers != mod.Version {
 				mod.Query = vers
 			}
@@ -237,7 +237,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 			var v string
 			if mg == nil {
 				var ok bool
-				v, ok = rs.rootSelected(LoaderState, arg)
+				v, ok = rs.rootSelected(loaderstate, arg)
 				if !ok {
 					// We checked rootSelected(arg) in the earlier args loop, so if there
 					// is no such root we should have loaded a non-nil mg.
@@ -251,7 +251,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 				continue
 			}
 			if v != "none" {
-				mods = append(mods, moduleInfo(LoaderState, ctx, rs, module.Version{Path: arg, Version: v}, mode, reuse))
+				mods = append(mods, moduleInfo(loaderstate, ctx, rs, module.Version{Path: arg, Version: v}, mode, reuse))
 			} else if cfg.BuildMod == "vendor" {
 				// In vendor mode, we can't determine whether a missing module is “a
 				// known dependency” because the module graph is incomplete.
@@ -292,7 +292,7 @@ func listModules(ctx context.Context, rs *Requirements, args []string, mode List
 		fetchedMods := make([]*modinfo.ModulePublic, len(matches))
 		for i, m := range matches {
 			q.Add(func() {
-				fetchedMods[i] = moduleInfo(LoaderState, ctx, rs, m, mode, reuse)
+				fetchedMods[i] = moduleInfo(loaderstate, ctx, rs, m, mode, reuse)
 			})
 		}
 		<-q.Idle()
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 5e5d79a39f001f..b17b080a89c08e 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -1181,7 +1181,7 @@ func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts,
 			Paths: cfg.BuildCoverPkg,
 		}
 	}
-	pmain, ptest, pxtest, perr := load.TestPackagesFor(ctx, pkgOpts, p, cover)
+	pmain, ptest, pxtest, perr := load.TestPackagesFor(modload.LoaderState, ctx, pkgOpts, p, cover)
 	if perr != nil {
 		return nil, nil, nil, perr, perr.Error
 	}
diff --git a/src/cmd/go/internal/vet/vet.go b/src/cmd/go/internal/vet/vet.go
index 7c79dccd539aa0..5874869cdbf1fe 100644
--- a/src/cmd/go/internal/vet/vet.go
+++ b/src/cmd/go/internal/vet/vet.go
@@ -249,7 +249,7 @@ func run(ctx context.Context, cmd *base.Command, args []string) {
 
 	root := &work.Action{Mode: "go " + cmd.Name()}
 	for _, p := range pkgs {
-		_, ptest, pxtest, perr := load.TestPackagesFor(ctx, pkgOpts, p, nil)
+		_, ptest, pxtest, perr := load.TestPackagesFor(modload.LoaderState, ctx, pkgOpts, p, nil)
 		if perr != nil {
 			base.Errorf("%v", perr.Error)
 			continue
diff --git a/src/cmd/go/internal/work/action.go b/src/cmd/go/internal/work/action.go
index f1f3bcea38d9d5..29f256a48295ae 100644
--- a/src/cmd/go/internal/work/action.go
+++ b/src/cmd/go/internal/work/action.go
@@ -444,9 +444,9 @@ func (b *Builder) cacheAction(mode string, p *load.Package, f func() *Action) *A
 }
 
 // AutoAction returns the "right" action for go build or go install of p.
-func (b *Builder) AutoAction(mode, depMode BuildMode, p *load.Package) *Action {
+func (b *Builder) AutoAction(loaderstate *modload.State, mode, depMode BuildMode, p *load.Package) *Action {
 	if p.Name == "main" {
-		return b.LinkAction(modload.LoaderState, mode, depMode, p)
+		return b.LinkAction(loaderstate, mode, depMode, p)
 	}
 	return b.CompileAction(mode, depMode, p)
 }
diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index 45acbe85c2a6d0..c02273664396ac 100644
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -527,7 +527,7 @@ func runBuild(ctx context.Context, cmd *base.Command, args []string) {
 				p.Target += cfg.ExeSuffix
 				p.Stale = true
 				p.StaleReason = "build -o flag in use"
-				a.Deps = append(a.Deps, b.AutoAction(ModeInstall, depMode, p))
+				a.Deps = append(a.Deps, b.AutoAction(modload.LoaderState, ModeInstall, depMode, p))
 			}
 			if len(a.Deps) == 0 {
 				base.Fatalf("go: no main packages to build")
@@ -544,14 +544,14 @@ func runBuild(ctx context.Context, cmd *base.Command, args []string) {
 		p.Target = cfg.BuildO
 		p.Stale = true // must build - not up to date
 		p.StaleReason = "build -o flag in use"
-		a := b.AutoAction(ModeInstall, depMode, p)
+		a := b.AutoAction(modload.LoaderState, ModeInstall, depMode, p)
 		b.Do(ctx, a)
 		return
 	}
 
 	a := &Action{Mode: "go build"}
 	for _, p := range pkgs {
-		a.Deps = append(a.Deps, b.AutoAction(ModeBuild, depMode, p))
+		a.Deps = append(a.Deps, b.AutoAction(modload.LoaderState, ModeBuild, depMode, p))
 	}
 	if cfg.BuildBuildmode == "shared" {
 		a = b.buildmodeShared(ModeBuild, depMode, args, pkgs, a)
@@ -797,7 +797,7 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
 		// If p is a tool, delay the installation until the end of the build.
 		// This avoids installing assemblers/compilers that are being executed
 		// by other steps in the build.
-		a1 := b.AutoAction(ModeInstall, depMode, p)
+		a1 := b.AutoAction(modload.LoaderState, ModeInstall, depMode, p)
 		if load.InstallTargetDir(p) == load.ToTool {
 			a.Deps = append(a.Deps, a1.Deps...)
 			a1.Deps = append(a1.Deps, a)

From 441e7194a44efe5beb98d329db5529bfc658f2e0 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 2 Oct 2025 09:43:40 -0400
Subject: [PATCH 181/229] cmd/go: inject State parameter into `test.runTest`

This command modifies the call tree starting at `test.runTest` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/test
rf 'inject modload.LoaderState runTest'
cd ..
./rf-cleanup.zsh

Change-Id: I6ee495c3beabdc5568ad338f4998a5927491db1a
Reviewed-on: https://go-review.googlesource.com/c/go/+/709986
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/load/pkg.go    |  4 ++--
 src/cmd/go/internal/test/test.go   | 22 +++++++++++-----------
 src/cmd/go/internal/vet/vet.go     |  4 ++--
 src/cmd/go/internal/work/action.go |  8 ++++----
 4 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index fedb313b1f5725..554963240049e4 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -2797,7 +2797,7 @@ func PackageList(roots []*Package) []*Package {
 // TestPackageList returns the list of packages in the dag rooted at roots
 // as visited in a depth-first post-order traversal, including the test
 // imports of the roots. This ignores errors in test packages.
-func TestPackageList(ctx context.Context, opts PackageOpts, roots []*Package) []*Package {
+func TestPackageList(loaderstate *modload.State, ctx context.Context, opts PackageOpts, roots []*Package) []*Package {
 	seen := map[*Package]bool{}
 	all := []*Package{}
 	var walk func(*Package)
@@ -2813,7 +2813,7 @@ func TestPackageList(ctx context.Context, opts PackageOpts, roots []*Package) []
 	}
 	walkTest := func(root *Package, path string) {
 		var stk ImportStack
-		p1, err := loadImport(modload.LoaderState, ctx, opts, nil, path, root.Dir, root, &stk, root.Internal.Build.TestImportPos[path], ResolveImport)
+		p1, err := loadImport(loaderstate, ctx, opts, nil, path, root.Dir, root, &stk, root.Internal.Build.TestImportPos[path], ResolveImport)
 		if err != nil && root.Error == nil {
 			// Assign error importing the package to the importer.
 			root.Error = err
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index b17b080a89c08e..70207cfbd13267 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -872,7 +872,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 
 		// Select for coverage all dependencies matching the -coverpkg
 		// patterns.
-		plist := load.TestPackageList(ctx, pkgOpts, pkgs)
+		plist := load.TestPackageList(modload.LoaderState, ctx, pkgOpts, pkgs)
 		testCoverPkgs = load.SelectCoverPackages(modload.LoaderState, plist, match, "test")
 		if len(testCoverPkgs) > 0 {
 			// create a new singleton action that will collect up the
@@ -951,7 +951,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 			"testing":               true,
 			"time":                  true,
 		}
-		for _, p := range load.TestPackageList(ctx, pkgOpts, pkgs) {
+		for _, p := range load.TestPackageList(modload.LoaderState, ctx, pkgOpts, pkgs) {
 			if !skipInstrumentation[p.ImportPath] {
 				p.Internal.FuzzInstrument = true
 			}
@@ -1048,7 +1048,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
 			reportSetupFailed(firstErrPkg, firstErrPkg.Error)
 			continue
 		}
-		buildTest, runTest, printTest, perr, err := builderTest(b, ctx, pkgOpts, p, allImports[p], writeCoverMetaAct)
+		buildTest, runTest, printTest, perr, err := builderTest(modload.LoaderState, b, ctx, pkgOpts, p, allImports[p], writeCoverMetaAct)
 		if err != nil {
 			reportErr(perr, err)
 			reportSetupFailed(perr, err)
@@ -1129,7 +1129,7 @@ var windowsBadWords = []string{
 	"update",
 }
 
-func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts, p *load.Package, imported bool, writeCoverMetaAct *work.Action) (buildAction, runAction, printAction *work.Action, perr *load.Package, err error) {
+func builderTest(loaderstate *modload.State, b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts, p *load.Package, imported bool, writeCoverMetaAct *work.Action) (buildAction, runAction, printAction *work.Action, perr *load.Package, err error) {
 	if len(p.TestGoFiles)+len(p.XTestGoFiles) == 0 {
 		build := b.CompileAction(work.ModeBuild, work.ModeBuild, p)
 		run := &work.Action{
@@ -1157,7 +1157,7 @@ func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts,
 			run.Deps = append(run.Deps, writeCoverMetaAct)
 			writeCoverMetaAct.Deps = append(writeCoverMetaAct.Deps, build)
 		}
-		addTestVet(b, p, run, nil)
+		addTestVet(loaderstate, b, p, run, nil)
 		print := &work.Action{
 			Mode:       "test print",
 			Actor:      work.ActorFunc(builderPrintTest),
@@ -1181,7 +1181,7 @@ func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts,
 			Paths: cfg.BuildCoverPkg,
 		}
 	}
-	pmain, ptest, pxtest, perr := load.TestPackagesFor(modload.LoaderState, ctx, pkgOpts, p, cover)
+	pmain, ptest, pxtest, perr := load.TestPackagesFor(loaderstate, ctx, pkgOpts, p, cover)
 	if perr != nil {
 		return nil, nil, nil, perr, perr.Error
 	}
@@ -1221,7 +1221,7 @@ func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts,
 		}
 	}
 
-	a := b.LinkAction(modload.LoaderState, work.ModeBuild, work.ModeBuild, pmain)
+	a := b.LinkAction(loaderstate, work.ModeBuild, work.ModeBuild, pmain)
 	a.Target = testDir + testBinary + cfg.ExeSuffix
 	if cfg.Goos == "windows" {
 		// There are many reserved words on Windows that,
@@ -1347,10 +1347,10 @@ func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts,
 	}
 
 	if len(ptest.GoFiles)+len(ptest.CgoFiles) > 0 {
-		addTestVet(b, ptest, vetRunAction, installAction)
+		addTestVet(loaderstate, b, ptest, vetRunAction, installAction)
 	}
 	if pxtest != nil {
-		addTestVet(b, pxtest, vetRunAction, installAction)
+		addTestVet(loaderstate, b, pxtest, vetRunAction, installAction)
 	}
 
 	if installAction != nil {
@@ -1365,12 +1365,12 @@ func builderTest(b *work.Builder, ctx context.Context, pkgOpts load.PackageOpts,
 	return buildAction, runAction, printAction, nil, nil
 }
 
-func addTestVet(b *work.Builder, p *load.Package, runAction, installAction *work.Action) {
+func addTestVet(loaderstate *modload.State, b *work.Builder, p *load.Package, runAction, installAction *work.Action) {
 	if testVet.off {
 		return
 	}
 
-	vet := b.VetAction(work.ModeBuild, work.ModeBuild, p)
+	vet := b.VetAction(loaderstate, work.ModeBuild, work.ModeBuild, p)
 	runAction.Deps = append(runAction.Deps, vet)
 	// Install will clean the build directory.
 	// Make sure vet runs first.
diff --git a/src/cmd/go/internal/vet/vet.go b/src/cmd/go/internal/vet/vet.go
index 5874869cdbf1fe..4de71bcdb9b948 100644
--- a/src/cmd/go/internal/vet/vet.go
+++ b/src/cmd/go/internal/vet/vet.go
@@ -260,10 +260,10 @@ func run(ctx context.Context, cmd *base.Command, args []string) {
 		}
 		if len(ptest.GoFiles) > 0 || len(ptest.CgoFiles) > 0 {
 			// The test package includes all the files of primary package.
-			root.Deps = append(root.Deps, b.VetAction(work.ModeBuild, work.ModeBuild, ptest))
+			root.Deps = append(root.Deps, b.VetAction(modload.LoaderState, work.ModeBuild, work.ModeBuild, ptest))
 		}
 		if pxtest != nil {
-			root.Deps = append(root.Deps, b.VetAction(work.ModeBuild, work.ModeBuild, pxtest))
+			root.Deps = append(root.Deps, b.VetAction(modload.LoaderState, work.ModeBuild, work.ModeBuild, pxtest))
 		}
 	}
 	b.Do(ctx, root)
diff --git a/src/cmd/go/internal/work/action.go b/src/cmd/go/internal/work/action.go
index 29f256a48295ae..7ef7686942a260 100644
--- a/src/cmd/go/internal/work/action.go
+++ b/src/cmd/go/internal/work/action.go
@@ -867,13 +867,13 @@ func (b *Builder) cgoAction(p *load.Package, objdir string, deps []*Action, hasC
 // It depends on the action for compiling p.
 // If the caller may be causing p to be installed, it is up to the caller
 // to make sure that the install depends on (runs after) vet.
-func (b *Builder) VetAction(mode, depMode BuildMode, p *load.Package) *Action {
-	a := b.vetAction(mode, depMode, p)
+func (b *Builder) VetAction(loaderstate *modload.State, mode, depMode BuildMode, p *load.Package) *Action {
+	a := b.vetAction(loaderstate, mode, depMode, p)
 	a.VetxOnly = false
 	return a
 }
 
-func (b *Builder) vetAction(mode, depMode BuildMode, p *load.Package) *Action {
+func (b *Builder) vetAction(loaderstate *modload.State, mode, depMode BuildMode, p *load.Package) *Action {
 	// Construct vet action.
 	a := b.cacheAction("vet", p, func() *Action {
 		a1 := b.CompileAction(mode|ModeVetOnly, depMode, p)
@@ -889,7 +889,7 @@ func (b *Builder) vetAction(mode, depMode BuildMode, p *load.Package) *Action {
 			deps = []*Action{a1}
 		}
 		for _, p1 := range p.Internal.Imports {
-			deps = append(deps, b.vetAction(mode, depMode, p1))
+			deps = append(deps, b.vetAction(loaderstate, mode, depMode, p1))
 		}
 
 		a := &Action{

From a420aa221ecae56d026e55dc64d647aec167f819 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 8 Oct 2025 14:58:18 -0400
Subject: [PATCH 182/229] cmd/go: inject State parameter into `tool.runTool`

This command modifies the call tree starting at `tool.runTool` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/tool
rf 'inject modload.LoaderState runTool'
cd ..
./rf-cleanup.zsh

Change-Id: Icd1ce189f7dad421eaa2bd43d53ceaf443c5405e
Reviewed-on: https://go-review.googlesource.com/c/go/+/710302
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/tool/tool.go | 42 ++++++++++++++++----------------
 1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/cmd/go/internal/tool/tool.go b/src/cmd/go/internal/tool/tool.go
index e95b07d8c813aa..75a8fab78ad31b 100644
--- a/src/cmd/go/internal/tool/tool.go
+++ b/src/cmd/go/internal/tool/tool.go
@@ -80,7 +80,7 @@ func init() {
 func runTool(ctx context.Context, cmd *base.Command, args []string) {
 	if len(args) == 0 {
 		counter.Inc("go/subcommand:tool")
-		listTools(ctx)
+		listTools(modload.LoaderState, ctx)
 		return
 	}
 	toolName := args[0]
@@ -108,14 +108,14 @@ func runTool(ctx context.Context, cmd *base.Command, args []string) {
 		if tool := loadBuiltinTool(toolName); tool != "" {
 			// Increment a counter for the tool subcommand with the tool name.
 			counter.Inc("go/subcommand:tool-" + toolName)
-			buildAndRunBuiltinTool(ctx, toolName, tool, args[1:])
+			buildAndRunBuiltinTool(modload.LoaderState, ctx, toolName, tool, args[1:])
 			return
 		}
 
 		// Try to build and run mod tool.
-		tool := loadModTool(ctx, toolName)
+		tool := loadModTool(modload.LoaderState, ctx, toolName)
 		if tool != "" {
-			buildAndRunModtool(ctx, toolName, tool, args[1:])
+			buildAndRunModtool(modload.LoaderState, ctx, toolName, tool, args[1:])
 			return
 		}
 
@@ -132,7 +132,7 @@ func runTool(ctx context.Context, cmd *base.Command, args []string) {
 }
 
 // listTools prints a list of the available tools in the tools directory.
-func listTools(ctx context.Context) {
+func listTools(loaderstate *modload.State, ctx context.Context) {
 	f, err := os.Open(build.ToolDir)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "go: no tool directory: %s\n", err)
@@ -161,9 +161,9 @@ func listTools(ctx context.Context) {
 		fmt.Println(name)
 	}
 
-	modload.InitWorkfile(modload.LoaderState)
-	modload.LoadModFile(modload.LoaderState, ctx)
-	modTools := slices.Sorted(maps.Keys(modload.LoaderState.MainModules.Tools()))
+	modload.InitWorkfile(loaderstate)
+	modload.LoadModFile(loaderstate, ctx)
+	modTools := slices.Sorted(maps.Keys(loaderstate.MainModules.Tools()))
 	for _, tool := range modTools {
 		fmt.Println(tool)
 	}
@@ -251,12 +251,12 @@ func loadBuiltinTool(toolName string) string {
 	return cmdTool
 }
 
-func loadModTool(ctx context.Context, name string) string {
-	modload.InitWorkfile(modload.LoaderState)
-	modload.LoadModFile(modload.LoaderState, ctx)
+func loadModTool(loaderstate *modload.State, ctx context.Context, name string) string {
+	modload.InitWorkfile(loaderstate)
+	modload.LoadModFile(loaderstate, ctx)
 
 	matches := []string{}
-	for tool := range modload.LoaderState.MainModules.Tools() {
+	for tool := range loaderstate.MainModules.Tools() {
 		if tool == name || defaultExecName(tool) == name {
 			matches = append(matches, tool)
 		}
@@ -300,7 +300,7 @@ func builtTool(runAction *work.Action) string {
 	return linkAction.BuiltTarget()
 }
 
-func buildAndRunBuiltinTool(ctx context.Context, toolName, tool string, args []string) {
+func buildAndRunBuiltinTool(loaderstate *modload.State, ctx context.Context, toolName, tool string, args []string) {
 	// Override GOOS and GOARCH for the build to build the tool using
 	// the same GOOS and GOARCH as this go command.
 	cfg.ForceHost()
@@ -308,17 +308,17 @@ func buildAndRunBuiltinTool(ctx context.Context, toolName, tool string, args []s
 	// Ignore go.mod and go.work: we don't need them, and we want to be able
 	// to run the tool even if there's an issue with the module or workspace the
 	// user happens to be in.
-	modload.LoaderState.RootMode = modload.NoRoot
+	loaderstate.RootMode = modload.NoRoot
 
 	runFunc := func(b *work.Builder, ctx context.Context, a *work.Action) error {
 		cmdline := str.StringList(builtTool(a), a.Args)
 		return runBuiltTool(toolName, nil, cmdline)
 	}
 
-	buildAndRunTool(ctx, tool, args, runFunc)
+	buildAndRunTool(loaderstate, ctx, tool, args, runFunc)
 }
 
-func buildAndRunModtool(ctx context.Context, toolName, tool string, args []string) {
+func buildAndRunModtool(loaderstate *modload.State, ctx context.Context, toolName, tool string, args []string) {
 	runFunc := func(b *work.Builder, ctx context.Context, a *work.Action) error {
 		// Use the ExecCmd to run the binary, as go run does. ExecCmd allows users
 		// to provide a runner to run the binary, for example a simulator for binaries
@@ -332,11 +332,11 @@ func buildAndRunModtool(ctx context.Context, toolName, tool string, args []strin
 		return runBuiltTool(toolName, env, cmdline)
 	}
 
-	buildAndRunTool(ctx, tool, args, runFunc)
+	buildAndRunTool(loaderstate, ctx, tool, args, runFunc)
 }
 
-func buildAndRunTool(ctx context.Context, tool string, args []string, runTool work.ActorFunc) {
-	work.BuildInit(modload.LoaderState)
+func buildAndRunTool(loaderstate *modload.State, ctx context.Context, tool string, args []string, runTool work.ActorFunc) {
+	work.BuildInit(loaderstate)
 	b := work.NewBuilder("")
 	defer func() {
 		if err := b.Close(); err != nil {
@@ -345,11 +345,11 @@ func buildAndRunTool(ctx context.Context, tool string, args []string, runTool wo
 	}()
 
 	pkgOpts := load.PackageOpts{MainOnly: true}
-	p := load.PackagesAndErrors(modload.LoaderState, ctx, pkgOpts, []string{tool})[0]
+	p := load.PackagesAndErrors(loaderstate, ctx, pkgOpts, []string{tool})[0]
 	p.Internal.OmitDebug = true
 	p.Internal.ExeName = p.DefaultExecName()
 
-	a1 := b.LinkAction(modload.LoaderState, work.ModeBuild, work.ModeBuild, p)
+	a1 := b.LinkAction(loaderstate, work.ModeBuild, work.ModeBuild, p)
 	a1.CacheExecutable = true
 	a := &work.Action{Mode: "go tool", Actor: runTool, Args: args, Deps: []*work.Action{a1}}
 	b.Do(ctx, a)

From 386d81151d6f297cec757e2ad6d89f146759703a Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 16 Oct 2025 18:06:27 -0400
Subject: [PATCH 183/229] cmd/go: make setState work with any State instance

This commit updates the setState function to work with any state
object in preparation for converting it to a method.

This commit is part of the overall effort to eliminate global
modloader state.

Change-Id: I6d485156e7c4c83ff608f941b68e6d928418bd8f
Reviewed-on: https://go-review.googlesource.com/c/go/+/712700
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/modload/init.go | 40 ++++++++++++++---------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 383ea20e3e673a..34af9796e59ad1 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -81,7 +81,7 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	}
 
 	// Reset the state to a clean state.
-	oldstate := setState(State{})
+	oldstate := setState(LoaderState, State{})
 	LoaderState.ForceUseModules = true
 
 	// Load in workspace mode.
@@ -93,7 +93,7 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	LoaderState.requirements = requirementsFromModFiles(LoaderState, ctx, LoaderState.MainModules.workFile, slices.Collect(maps.Values(LoaderState.MainModules.modFiles)), nil)
 
 	return func() {
-		setState(oldstate)
+		setState(LoaderState, oldstate)
 	}, nil
 }
 
@@ -378,31 +378,31 @@ func WorkFilePath(loaderstate *State) string {
 // Reset clears all the initialized, cached state about the use of modules,
 // so that we can start over.
 func Reset() {
-	setState(State{})
+	setState(LoaderState, State{})
 }
 
-func setState(s State) State {
+func setState(s *State, new State) State {
 	oldState := State{
-		initialized:     LoaderState.initialized,
-		ForceUseModules: LoaderState.ForceUseModules,
-		RootMode:        LoaderState.RootMode,
-		modRoots:        LoaderState.modRoots,
+		initialized:     s.initialized,
+		ForceUseModules: s.ForceUseModules,
+		RootMode:        s.RootMode,
+		modRoots:        s.modRoots,
 		modulesEnabled:  cfg.ModulesEnabled,
-		MainModules:     LoaderState.MainModules,
-		requirements:    LoaderState.requirements,
-	}
-	LoaderState.initialized = s.initialized
-	LoaderState.ForceUseModules = s.ForceUseModules
-	LoaderState.RootMode = s.RootMode
-	LoaderState.modRoots = s.modRoots
-	cfg.ModulesEnabled = s.modulesEnabled
-	LoaderState.MainModules = s.MainModules
-	LoaderState.requirements = s.requirements
-	LoaderState.workFilePath = s.workFilePath
+		MainModules:     s.MainModules,
+		requirements:    s.requirements,
+	}
+	s.initialized = new.initialized
+	s.ForceUseModules = new.ForceUseModules
+	s.RootMode = new.RootMode
+	s.modRoots = new.modRoots
+	cfg.ModulesEnabled = new.modulesEnabled
+	s.MainModules = new.MainModules
+	s.requirements = new.requirements
+	s.workFilePath = new.workFilePath
 	// The modfetch package's global state is used to compute
 	// the go.sum file, so save and restore it along with the
 	// modload state.
-	oldState.modfetchState = modfetch.SetState(s.modfetchState)
+	oldState.modfetchState = modfetch.SetState(new.modfetchState)
 	return oldState
 }
 

From 0d3044f9655c3a3f94565b2918515d93f6fe2485 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 16 Oct 2025 18:09:57 -0400
Subject: [PATCH 184/229] cmd/go: make Reset work with any State instance

This commit updates the Reset function to work with any state
object in preparation for converting it to a method.

This commit is part of the overall effort to eliminate global
modloader state.

Change-Id: I6103842ea0a0528698217930afc0e34a2aa21eea
Reviewed-on: https://go-review.googlesource.com/c/go/+/712701
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/modload/init.go     | 4 ++--
 src/cmd/go/internal/toolchain/select.go | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 34af9796e59ad1..d250d65671305a 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -377,8 +377,8 @@ func WorkFilePath(loaderstate *State) string {
 
 // Reset clears all the initialized, cached state about the use of modules,
 // so that we can start over.
-func Reset() {
-	setState(LoaderState, State{})
+func Reset(s *State) {
+	setState(s, State{})
 }
 
 func setState(s *State, new State) State {
diff --git a/src/cmd/go/internal/toolchain/select.go b/src/cmd/go/internal/toolchain/select.go
index d54277ed1b4bea..b42f3dce058b5c 100644
--- a/src/cmd/go/internal/toolchain/select.go
+++ b/src/cmd/go/internal/toolchain/select.go
@@ -352,7 +352,7 @@ func Exec(gotoolchain string) {
 	}
 
 	// Set up modules without an explicit go.mod, to download distribution.
-	modload.Reset()
+	modload.Reset(modload.LoaderState)
 	modload.LoaderState.ForceUseModules = true
 	modload.LoaderState.RootMode = modload.NoRoot
 	modload.Init(modload.LoaderState)
@@ -695,7 +695,7 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 	modload.LoaderState.ForceUseModules = true
 	modload.LoaderState.RootMode = modload.NoRoot
 	modload.Init(modload.LoaderState)
-	defer modload.Reset()
+	defer modload.Reset(modload.LoaderState)
 
 	// See internal/load.PackagesAndErrorsOutsideModule
 	ctx := context.Background()

From bcf7da1595da24e36f2750ee244523b5972233a1 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 16 Oct 2025 18:15:14 -0400
Subject: [PATCH 185/229] cmd/go: convert functions to methods

This commit converts the Reset and setState functions to methods.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modload
rf '
  mv setState State.setState
  mv Reset State.Reset
'

Change-Id: Ibc40071dc044ef5d1ab0a0b03f17b75243a42011
Reviewed-on: https://go-review.googlesource.com/c/go/+/712702
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modload/init.go     | 10 +++++-----
 src/cmd/go/internal/toolchain/select.go |  4 ++--
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index d250d65671305a..9e07c72aa6583c 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -81,7 +81,7 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	}
 
 	// Reset the state to a clean state.
-	oldstate := setState(LoaderState, State{})
+	oldstate := LoaderState.setState(State{})
 	LoaderState.ForceUseModules = true
 
 	// Load in workspace mode.
@@ -93,7 +93,7 @@ func EnterWorkspace(ctx context.Context) (exit func(), err error) {
 	LoaderState.requirements = requirementsFromModFiles(LoaderState, ctx, LoaderState.MainModules.workFile, slices.Collect(maps.Values(LoaderState.MainModules.modFiles)), nil)
 
 	return func() {
-		setState(LoaderState, oldstate)
+		LoaderState.setState(oldstate)
 	}, nil
 }
 
@@ -377,11 +377,11 @@ func WorkFilePath(loaderstate *State) string {
 
 // Reset clears all the initialized, cached state about the use of modules,
 // so that we can start over.
-func Reset(s *State) {
-	setState(s, State{})
+func (s *State) Reset() {
+	s.setState(State{})
 }
 
-func setState(s *State, new State) State {
+func (s *State) setState(new State) State {
 	oldState := State{
 		initialized:     s.initialized,
 		ForceUseModules: s.ForceUseModules,
diff --git a/src/cmd/go/internal/toolchain/select.go b/src/cmd/go/internal/toolchain/select.go
index b42f3dce058b5c..8aa84e885f58bf 100644
--- a/src/cmd/go/internal/toolchain/select.go
+++ b/src/cmd/go/internal/toolchain/select.go
@@ -352,7 +352,7 @@ func Exec(gotoolchain string) {
 	}
 
 	// Set up modules without an explicit go.mod, to download distribution.
-	modload.Reset(modload.LoaderState)
+	modload.LoaderState.Reset()
 	modload.LoaderState.ForceUseModules = true
 	modload.LoaderState.RootMode = modload.NoRoot
 	modload.Init(modload.LoaderState)
@@ -695,7 +695,7 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 	modload.LoaderState.ForceUseModules = true
 	modload.LoaderState.RootMode = modload.NoRoot
 	modload.Init(modload.LoaderState)
-	defer modload.Reset(modload.LoaderState)
+	defer modload.LoaderState.Reset()
 
 	// See internal/load.PackagesAndErrorsOutsideModule
 	ctx := context.Background()

From 4dc3dd9a8615c88bef9247c9bab57e2b04bc662e Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 16 Oct 2025 17:43:58 -0400
Subject: [PATCH 186/229] cmd/go: add loaderstate to Switcher

Temporarily add modload.State field to the Switcher implementation.
Note that we cannot modify the gover.Switcher interface because doing
so creates an import cycle.

This commit is part of the overall effort to eliminate global
modloader state.

Change-Id: I20dba76328aa3d0df58caff75b174522bf9df9d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/712703
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modcmd/download.go  |  4 ++--
 src/cmd/go/internal/modcmd/tidy.go      |  2 +-
 src/cmd/go/internal/modget/get.go       |  4 ++--
 src/cmd/go/internal/toolchain/select.go | 14 +++++++-------
 src/cmd/go/internal/toolchain/switch.go | 16 ++++++++++++----
 src/cmd/go/internal/workcmd/use.go      |  2 +-
 6 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/src/cmd/go/internal/modcmd/download.go b/src/cmd/go/internal/modcmd/download.go
index e5e0e927b04ebe..0d223b382692f6 100644
--- a/src/cmd/go/internal/modcmd/download.go
+++ b/src/cmd/go/internal/modcmd/download.go
@@ -211,7 +211,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	// toolchain version) or only one module (as is used by the Go Module Proxy).
 
 	if infosErr != nil {
-		var sw toolchain.Switcher
+		sw := toolchain.NewSwitcher(modload.LoaderState)
 		sw.Error(infosErr)
 		if sw.NeedSwitch() {
 			sw.Switch(ctx)
@@ -292,7 +292,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	// which may include dependencies that are normally pruned out
 	// of the individual modules in the workspace.
 	if haveExplicitArgs || modload.WorkFilePath(modload.LoaderState) != "" {
-		var sw toolchain.Switcher
+		sw := toolchain.NewSwitcher(modload.LoaderState)
 		// Add errors to the Switcher in deterministic order so that they will be
 		// logged deterministically.
 		for _, m := range mods {
diff --git a/src/cmd/go/internal/modcmd/tidy.go b/src/cmd/go/internal/modcmd/tidy.go
index c693bd52a38af9..8a8b4e34c0cf71 100644
--- a/src/cmd/go/internal/modcmd/tidy.go
+++ b/src/cmd/go/internal/modcmd/tidy.go
@@ -141,6 +141,6 @@ func runTidy(ctx context.Context, cmd *base.Command, args []string) {
 		LoadTests:                true,
 		AllowErrors:              tidyE,
 		SilenceMissingStdImports: true,
-		Switcher:                 new(toolchain.Switcher),
+		Switcher:                 toolchain.NewSwitcher(modload.LoaderState),
 	}, "all")
 }
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index b26406ee1d0fa2..8972e4152e0779 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -1260,7 +1260,7 @@ func (r *resolver) loadPackages(ctx context.Context, patterns []string, findPack
 		LoadTests:                *getT,
 		AssumeRootsImported:      true, // After 'go get foo', imports of foo should build.
 		SilencePackageErrors:     true, // May be fixed by subsequent upgrades or downgrades.
-		Switcher:                 new(toolchain.Switcher),
+		Switcher:                 toolchain.NewSwitcher(modload.LoaderState),
 	}
 
 	opts.AllowPackage = func(ctx context.Context, path string, m module.Version) error {
@@ -1346,7 +1346,7 @@ func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (change
 
 		// If we found modules that were too new, find the max of the required versions
 		// and then try to switch to a newer toolchain.
-		var sw toolchain.Switcher
+		sw := toolchain.NewSwitcher(modload.LoaderState)
 		for _, q := range queries {
 			for _, cs := range q.candidates {
 				sw.Error(cs.err)
diff --git a/src/cmd/go/internal/toolchain/select.go b/src/cmd/go/internal/toolchain/select.go
index 8aa84e885f58bf..8a7e51c1437557 100644
--- a/src/cmd/go/internal/toolchain/select.go
+++ b/src/cmd/go/internal/toolchain/select.go
@@ -283,7 +283,7 @@ func Select() {
 	}
 
 	counterSelectExec.Inc()
-	Exec(gotoolchain)
+	Exec(modload.LoaderState, gotoolchain)
 }
 
 var counterSelectExec = counter.New("go/toolchain/select-exec")
@@ -300,7 +300,7 @@ var TestVersionSwitch string
 // If $GOTOOLCHAIN is set to path or min+path, Exec only considers the PATH
 // as a source of Go toolchains. Otherwise Exec tries the PATH but then downloads
 // a toolchain if necessary.
-func Exec(gotoolchain string) {
+func Exec(s *modload.State, gotoolchain string) {
 	log.SetPrefix("go: ")
 
 	writeBits = sysWriteBits()
@@ -352,10 +352,10 @@ func Exec(gotoolchain string) {
 	}
 
 	// Set up modules without an explicit go.mod, to download distribution.
-	modload.LoaderState.Reset()
-	modload.LoaderState.ForceUseModules = true
-	modload.LoaderState.RootMode = modload.NoRoot
-	modload.Init(modload.LoaderState)
+	s.Reset()
+	s.ForceUseModules = true
+	s.RootMode = modload.NoRoot
+	modload.Init(s)
 
 	// Download and unpack toolchain module into module cache.
 	// Note that multiple go commands might be doing this at the same time,
@@ -709,7 +709,7 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 	if errors.Is(err, gover.ErrTooNew) {
 		// Run early switch, same one go install or go run would eventually do,
 		// if it understood all the command-line flags.
-		var s Switcher
+		s := NewSwitcher(modload.LoaderState)
 		s.Error(err)
 		if s.TooNew != nil && gover.Compare(s.TooNew.GoVersion, minVers) > 0 {
 			SwitchOrFatal(ctx, err)
diff --git a/src/cmd/go/internal/toolchain/switch.go b/src/cmd/go/internal/toolchain/switch.go
index 37c1bcdcbec656..9fedea3abbf4b7 100644
--- a/src/cmd/go/internal/toolchain/switch.go
+++ b/src/cmd/go/internal/toolchain/switch.go
@@ -16,6 +16,7 @@ import (
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/gover"
 	"cmd/go/internal/modfetch"
+	"cmd/go/internal/modload"
 	"cmd/internal/telemetry/counter"
 )
 
@@ -31,8 +32,15 @@ import (
 //
 // See https://go.dev/doc/toolchain#switch.
 type Switcher struct {
-	TooNew *gover.TooNewError // max go requirement observed
-	Errors []error            // errors collected so far
+	TooNew      *gover.TooNewError // max go requirement observed
+	Errors      []error            // errors collected so far
+	loaderstate *modload.State     // temporarily here while we eliminate global module loader state
+}
+
+func NewSwitcher(s *modload.State) *Switcher {
+	sw := new(Switcher)
+	sw.loaderstate = s
+	return sw
 }
 
 // Error reports the error to the Switcher,
@@ -100,7 +108,7 @@ func (s *Switcher) Switch(ctx context.Context) {
 
 	fmt.Fprintf(os.Stderr, "go: %v requires go >= %v; switching to %v\n", s.TooNew.What, s.TooNew.GoVersion, tv)
 	counterSwitchExec.Inc()
-	Exec(tv)
+	Exec(s.loaderstate, tv)
 	panic("unreachable")
 }
 
@@ -109,7 +117,7 @@ var counterSwitchExec = counter.New("go/toolchain/switch-exec")
 // SwitchOrFatal attempts a toolchain switch based on the information in err
 // and otherwise falls back to base.Fatal(err).
 func SwitchOrFatal(ctx context.Context, err error) {
-	var s Switcher
+	s := NewSwitcher(modload.LoaderState)
 	s.Error(err)
 	s.Switch(ctx)
 	base.Exit()
diff --git a/src/cmd/go/internal/workcmd/use.go b/src/cmd/go/internal/workcmd/use.go
index ca8de22cca884f..367e8fe379fafb 100644
--- a/src/cmd/go/internal/workcmd/use.go
+++ b/src/cmd/go/internal/workcmd/use.go
@@ -94,7 +94,7 @@ func workUse(ctx context.Context, gowork string, wf *modfile.WorkFile, args []st
 	// all entries for the absolute path should be removed.
 	keepDirs := make(map[string]string)
 
-	var sw toolchain.Switcher
+	sw := toolchain.NewSwitcher(modload.LoaderState)
 
 	// lookDir updates the entry in keepDirs for the directory dir,
 	// which is either absolute or relative to the current working directory

From e7c66a58d50b93c2cd1a4eb51a437d750757177e Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 2 Oct 2025 21:45:53 -0400
Subject: [PATCH 187/229] cmd/go: inject State parameter into
 `toolchain.Select`

This command modifies the call tree starting at `toolchain.Select` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/toolchain
rf '
  inject modload.LoaderState Select
  add select.go var moduleLoaderState *modload.State
  ex {
    import "cmd/go/internal/modload";
    modload.LoaderState -> moduleLoaderState
  }
  add Select://+0 moduleLoaderState := modload.NewState()
  rm select.go:/var moduleLoaderState \*modload.State/
'
cd ..
./rf-cleanup.zsh

Change-Id: I759439a47e2b1aaa01a0a800bc18596dd7ce4983
Reviewed-on: https://go-review.googlesource.com/c/go/+/709988
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/modcmd/download.go        |  2 +-
 src/cmd/go/internal/modcmd/graph.go           |  2 +-
 src/cmd/go/internal/modcmd/tidy.go            |  2 +-
 src/cmd/go/internal/modget/get.go             | 10 +++----
 src/cmd/go/internal/modload/init.go           |  6 ++--
 .../internal/telemetrystats/telemetrystats.go |  2 +-
 src/cmd/go/internal/toolchain/select.go       | 29 ++++++++++---------
 src/cmd/go/internal/toolchain/switch.go       |  4 +--
 src/cmd/go/internal/workcmd/sync.go           |  2 +-
 9 files changed, 30 insertions(+), 29 deletions(-)

diff --git a/src/cmd/go/internal/modcmd/download.go b/src/cmd/go/internal/modcmd/download.go
index 0d223b382692f6..63eb6886a1a157 100644
--- a/src/cmd/go/internal/modcmd/download.go
+++ b/src/cmd/go/internal/modcmd/download.go
@@ -158,7 +158,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 					// TODO(#64008): call base.Fatalf instead of toolchain.SwitchOrFatal
 					// here, since we can only reach this point with an outdated toolchain
 					// if the go.mod file is inconsistent.
-					toolchain.SwitchOrFatal(ctx, err)
+					toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 				}
 
 				for _, m := range modFile.Require {
diff --git a/src/cmd/go/internal/modcmd/graph.go b/src/cmd/go/internal/modcmd/graph.go
index 3bc6009b57b595..aa3c9f45405240 100644
--- a/src/cmd/go/internal/modcmd/graph.go
+++ b/src/cmd/go/internal/modcmd/graph.go
@@ -62,7 +62,7 @@ func runGraph(ctx context.Context, cmd *base.Command, args []string) {
 
 	goVersion := graphGo.String()
 	if goVersion != "" && gover.Compare(gover.Local(), goVersion) < 0 {
-		toolchain.SwitchOrFatal(ctx, &gover.TooNewError{
+		toolchain.SwitchOrFatal(modload.LoaderState, ctx, &gover.TooNewError{
 			What:      "-go flag",
 			GoVersion: goVersion,
 		})
diff --git a/src/cmd/go/internal/modcmd/tidy.go b/src/cmd/go/internal/modcmd/tidy.go
index 8a8b4e34c0cf71..fb66bbcda3a173 100644
--- a/src/cmd/go/internal/modcmd/tidy.go
+++ b/src/cmd/go/internal/modcmd/tidy.go
@@ -124,7 +124,7 @@ func runTidy(ctx context.Context, cmd *base.Command, args []string) {
 
 	goVersion := tidyGo.String()
 	if goVersion != "" && gover.Compare(gover.Local(), goVersion) < 0 {
-		toolchain.SwitchOrFatal(ctx, &gover.TooNewError{
+		toolchain.SwitchOrFatal(modload.LoaderState, ctx, &gover.TooNewError{
 			What:      "-go flag",
 			GoVersion: goVersion,
 		})
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index 8972e4152e0779..9de24c4508a5ee 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -418,7 +418,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 		// but the command line is not.
 		// TODO(bcmills): modload.EditBuildList should catch this instead,
 		// and then this can be changed to base.Fatal(err).
-		toolchain.SwitchOrFatal(ctx, err)
+		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 	}
 
 	newReqs := reqsFromGoMod(modload.ModFile())
@@ -558,7 +558,7 @@ func newResolver(ctx context.Context, queries []*query) *resolver {
 	// methods.
 	mg, err := modload.LoadModGraph(ctx, "")
 	if err != nil {
-		toolchain.SwitchOrFatal(ctx, err)
+		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 	}
 
 	buildList := mg.BuildList()
@@ -1619,7 +1619,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 			// are old enough but the go command itself is not new
 			// enough. See the related comment on the SwitchOrFatal
 			// in runGet when WriteGoMod returns an error.
-			toolchain.SwitchOrFatal(ctx, err)
+			toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 		}
 	}
 
@@ -1989,7 +1989,7 @@ func (r *resolver) updateBuildList(ctx context.Context, additions []module.Versi
 	changed, err := modload.EditBuildList(modload.LoaderState, ctx, additions, resolved)
 	if err != nil {
 		if errors.Is(err, gover.ErrTooNew) {
-			toolchain.SwitchOrFatal(ctx, err)
+			toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 		}
 
 		constraint, ok := errors.AsType[*modload.ConstraintError](err)
@@ -2035,7 +2035,7 @@ func (r *resolver) updateBuildList(ctx context.Context, additions []module.Versi
 
 	mg, err := modload.LoadModGraph(ctx, "")
 	if err != nil {
-		toolchain.SwitchOrFatal(ctx, err)
+		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 	}
 
 	r.buildList = mg.BuildList()
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 9e07c72aa6583c..9182f60ee7b1bb 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -570,12 +570,12 @@ func Init(loaderstate *State) {
 // of 'go get', but Init reads the -modfile flag in 'go get', so it shouldn't
 // be called until the command is installed and flags are parsed. Instead of
 // calling Init and Enabled, the main package can call this function.
-func WillBeEnabled() bool {
-	if LoaderState.modRoots != nil || cfg.ModulesEnabled {
+func WillBeEnabled(loaderstate *State) bool {
+	if loaderstate.modRoots != nil || cfg.ModulesEnabled {
 		// Already enabled.
 		return true
 	}
-	if LoaderState.initialized {
+	if loaderstate.initialized {
 		// Initialized, not enabled.
 		return false
 	}
diff --git a/src/cmd/go/internal/telemetrystats/telemetrystats.go b/src/cmd/go/internal/telemetrystats/telemetrystats.go
index 9586324551dfc9..077c2d817f0e14 100644
--- a/src/cmd/go/internal/telemetrystats/telemetrystats.go
+++ b/src/cmd/go/internal/telemetrystats/telemetrystats.go
@@ -22,7 +22,7 @@ func Increment() {
 // incrementConfig increments counters for the configuration
 // the command is running in.
 func incrementConfig() {
-	if !modload.WillBeEnabled() {
+	if !modload.WillBeEnabled(modload.LoaderState) {
 		counter.Inc("go/mode:gopath")
 	} else if workfile := modload.FindGoWork(modload.LoaderState, base.Cwd()); workfile != "" {
 		counter.Inc("go/mode:workspace")
diff --git a/src/cmd/go/internal/toolchain/select.go b/src/cmd/go/internal/toolchain/select.go
index 8a7e51c1437557..5a0600a9654ce0 100644
--- a/src/cmd/go/internal/toolchain/select.go
+++ b/src/cmd/go/internal/toolchain/select.go
@@ -95,10 +95,11 @@ var toolchainTrace = godebug.New("#toolchaintrace").Value() == "1"
 // It must be called early in startup.
 // See https://go.dev/doc/toolchain#select.
 func Select() {
+	moduleLoaderState := modload.NewState()
 	log.SetPrefix("go: ")
 	defer log.SetPrefix("")
 
-	if !modload.WillBeEnabled() {
+	if !modload.WillBeEnabled(moduleLoaderState) {
 		return
 	}
 
@@ -171,7 +172,7 @@ func Select() {
 	gotoolchain = minToolchain
 	if mode == "auto" || mode == "path" {
 		// Read go.mod to find new minimum and suggested toolchain.
-		file, goVers, toolchain := modGoToolchain()
+		file, goVers, toolchain := modGoToolchain(moduleLoaderState)
 		gover.Startup.AutoFile = file
 		if toolchain == "default" {
 			// "default" means always use the default toolchain,
@@ -231,7 +232,7 @@ func Select() {
 				}
 			}
 		}
-		maybeSwitchForGoInstallVersion(minVers)
+		maybeSwitchForGoInstallVersion(moduleLoaderState, minVers)
 	}
 
 	// If we are invoked as a target toolchain, confirm that
@@ -283,7 +284,7 @@ func Select() {
 	}
 
 	counterSelectExec.Inc()
-	Exec(modload.LoaderState, gotoolchain)
+	Exec(moduleLoaderState, gotoolchain)
 }
 
 var counterSelectExec = counter.New("go/toolchain/select-exec")
@@ -527,9 +528,9 @@ func raceSafeCopy(old, new string) error {
 // modGoToolchain finds the enclosing go.work or go.mod file
 // and returns the go version and toolchain lines from the file.
 // The toolchain line overrides the version line
-func modGoToolchain() (file, goVers, toolchain string) {
+func modGoToolchain(loaderstate *modload.State) (file, goVers, toolchain string) {
 	wd := base.UncachedCwd()
-	file = modload.FindGoWork(modload.LoaderState, wd)
+	file = modload.FindGoWork(loaderstate, wd)
 	// $GOWORK can be set to a file that does not yet exist, if we are running 'go work init'.
 	// Do not try to load the file in that case
 	if _, err := os.Stat(file); err != nil {
@@ -551,7 +552,7 @@ func modGoToolchain() (file, goVers, toolchain string) {
 
 // maybeSwitchForGoInstallVersion reports whether the command line is go install m@v or go run m@v.
 // If so, switch to the go version required to build m@v if it's higher than minVers.
-func maybeSwitchForGoInstallVersion(minVers string) {
+func maybeSwitchForGoInstallVersion(loaderstate *modload.State, minVers string) {
 	// Note: We assume there are no flags between 'go' and 'install' or 'run'.
 	// During testing there are some debugging flags that are accepted
 	// in that position, but in production go binaries there are not.
@@ -692,10 +693,10 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 	// command lines if we add new flags in the future.
 
 	// Set up modules without an explicit go.mod, to download go.mod.
-	modload.LoaderState.ForceUseModules = true
-	modload.LoaderState.RootMode = modload.NoRoot
-	modload.Init(modload.LoaderState)
-	defer modload.LoaderState.Reset()
+	loaderstate.ForceUseModules = true
+	loaderstate.RootMode = modload.NoRoot
+	modload.Init(loaderstate)
+	defer loaderstate.Reset()
 
 	// See internal/load.PackagesAndErrorsOutsideModule
 	ctx := context.Background()
@@ -705,14 +706,14 @@ func maybeSwitchForGoInstallVersion(minVers string) {
 		allowed = nil
 	}
 	noneSelected := func(path string) (version string) { return "none" }
-	_, err := modload.QueryPackages(modload.LoaderState, ctx, path, version, noneSelected, allowed)
+	_, err := modload.QueryPackages(loaderstate, ctx, path, version, noneSelected, allowed)
 	if errors.Is(err, gover.ErrTooNew) {
 		// Run early switch, same one go install or go run would eventually do,
 		// if it understood all the command-line flags.
-		s := NewSwitcher(modload.LoaderState)
+		s := NewSwitcher(loaderstate)
 		s.Error(err)
 		if s.TooNew != nil && gover.Compare(s.TooNew.GoVersion, minVers) > 0 {
-			SwitchOrFatal(ctx, err)
+			SwitchOrFatal(loaderstate, ctx, err)
 		}
 	}
 }
diff --git a/src/cmd/go/internal/toolchain/switch.go b/src/cmd/go/internal/toolchain/switch.go
index 9fedea3abbf4b7..76b608fdef4157 100644
--- a/src/cmd/go/internal/toolchain/switch.go
+++ b/src/cmd/go/internal/toolchain/switch.go
@@ -116,8 +116,8 @@ var counterSwitchExec = counter.New("go/toolchain/switch-exec")
 
 // SwitchOrFatal attempts a toolchain switch based on the information in err
 // and otherwise falls back to base.Fatal(err).
-func SwitchOrFatal(ctx context.Context, err error) {
-	s := NewSwitcher(modload.LoaderState)
+func SwitchOrFatal(loaderstate *modload.State, ctx context.Context, err error) {
+	s := NewSwitcher(loaderstate)
 	s.Error(err)
 	s.Switch(ctx)
 	base.Exit()
diff --git a/src/cmd/go/internal/workcmd/sync.go b/src/cmd/go/internal/workcmd/sync.go
index c58cd55ceee392..dfff0c29d227b1 100644
--- a/src/cmd/go/internal/workcmd/sync.go
+++ b/src/cmd/go/internal/workcmd/sync.go
@@ -56,7 +56,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 
 	_, err := modload.LoadModGraph(ctx, "")
 	if err != nil {
-		toolchain.SwitchOrFatal(ctx, err)
+		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 	}
 	mustSelectFor := map[module.Version][]module.Version{}
 

From e176dff41c42208d977e3c7adda4484febb73ec0 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 8 Oct 2025 14:51:13 -0400
Subject: [PATCH 188/229] cmd/go: inject State parameter into
 `modcmd.runDownload`

This command modifies the call tree starting at `modcmd.runDownload`
to inject a `State` parameter to every function that is currently
using the global `modload.LoaderState` variable.  By explicilty
passing a `State` parameter, we can begin to eliminate the usage of
the global `modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modcmd
rf 'inject modload.LoaderState runDownload'
cd ..
./rf-cleanup.zsh

Change-Id: I64cce3e631a2614b7fabe49205d9d41fc9ba24de
Reviewed-on: https://go-review.googlesource.com/c/go/+/710299
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/modcmd/download.go   |  6 +++---
 src/cmd/go/internal/modcmd/graph.go      |  2 +-
 src/cmd/go/internal/modcmd/verify.go     |  2 +-
 src/cmd/go/internal/modget/get.go        |  6 +++---
 src/cmd/go/internal/modload/buildlist.go | 14 +++++++-------
 src/cmd/go/internal/modload/init.go      |  6 +++---
 src/cmd/go/internal/workcmd/sync.go      |  4 ++--
 7 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/src/cmd/go/internal/modcmd/download.go b/src/cmd/go/internal/modcmd/download.go
index 63eb6886a1a157..1b2f850d1b4836 100644
--- a/src/cmd/go/internal/modcmd/download.go
+++ b/src/cmd/go/internal/modcmd/download.go
@@ -153,7 +153,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 				// However, we also need to load the full module graph, to ensure that
 				// we have downloaded enough of the module graph to run 'go list all',
 				// 'go mod graph', and similar commands.
-				_, err := modload.LoadModGraph(ctx, "")
+				_, err := modload.LoadModGraph(modload.LoaderState, ctx, "")
 				if err != nil {
 					// TODO(#64008): call base.Fatalf instead of toolchain.SwitchOrFatal
 					// here, since we can only reach this point with an outdated toolchain
@@ -231,7 +231,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 		// TODO(#64008): In the future, report an error if go.mod or go.sum need to
 		// be updated after loading the build list. This may require setting
 		// the mode to "mod" or "readonly" depending on haveExplicitArgs.
-		if err := modload.WriteGoMod(ctx, modload.WriteOpts{}); err != nil {
+		if err := modload.WriteGoMod(modload.LoaderState, ctx, modload.WriteOpts{}); err != nil {
 			base.Fatal(err)
 		}
 	}
@@ -348,7 +348,7 @@ func runDownload(ctx context.Context, cmd *base.Command, args []string) {
 	// Don't save sums for 'go mod download' without arguments unless we're in
 	// workspace mode; see comment above.
 	if haveExplicitArgs || modload.WorkFilePath(modload.LoaderState) != "" {
-		if err := modload.WriteGoMod(ctx, modload.WriteOpts{}); err != nil {
+		if err := modload.WriteGoMod(modload.LoaderState, ctx, modload.WriteOpts{}); err != nil {
 			base.Error(err)
 		}
 	}
diff --git a/src/cmd/go/internal/modcmd/graph.go b/src/cmd/go/internal/modcmd/graph.go
index aa3c9f45405240..2a1bad0e0efffd 100644
--- a/src/cmd/go/internal/modcmd/graph.go
+++ b/src/cmd/go/internal/modcmd/graph.go
@@ -68,7 +68,7 @@ func runGraph(ctx context.Context, cmd *base.Command, args []string) {
 		})
 	}
 
-	mg, err := modload.LoadModGraph(ctx, goVersion)
+	mg, err := modload.LoadModGraph(modload.LoaderState, ctx, goVersion)
 	if err != nil {
 		base.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/modcmd/verify.go b/src/cmd/go/internal/modcmd/verify.go
index d8227bcd5455a3..bf803fd2ebbaf5 100644
--- a/src/cmd/go/internal/modcmd/verify.go
+++ b/src/cmd/go/internal/modcmd/verify.go
@@ -57,7 +57,7 @@ func runVerify(ctx context.Context, cmd *base.Command, args []string) {
 	type token struct{}
 	sem := make(chan token, runtime.GOMAXPROCS(0))
 
-	mg, err := modload.LoadModGraph(ctx, "")
+	mg, err := modload.LoadModGraph(modload.LoaderState, ctx, "")
 	if err != nil {
 		base.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index 9de24c4508a5ee..b8018c04c987f4 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -412,7 +412,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	// Everything succeeded. Update go.mod.
 	oldReqs := reqsFromGoMod(modload.ModFile())
 
-	if err := modload.WriteGoMod(ctx, opts); err != nil {
+	if err := modload.WriteGoMod(modload.LoaderState, ctx, opts); err != nil {
 		// A TooNewError can happen for 'go get go@newversion'
 		// when all the required modules are old enough
 		// but the command line is not.
@@ -556,7 +556,7 @@ type matchInModuleKey struct {
 func newResolver(ctx context.Context, queries []*query) *resolver {
 	// LoadModGraph also sets modload.Target, which is needed by various resolver
 	// methods.
-	mg, err := modload.LoadModGraph(ctx, "")
+	mg, err := modload.LoadModGraph(modload.LoaderState, ctx, "")
 	if err != nil {
 		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 	}
@@ -2033,7 +2033,7 @@ func (r *resolver) updateBuildList(ctx context.Context, additions []module.Versi
 		return false
 	}
 
-	mg, err := modload.LoadModGraph(ctx, "")
+	mg, err := modload.LoadModGraph(modload.LoaderState, ctx, "")
 	if err != nil {
 		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 	}
diff --git a/src/cmd/go/internal/modload/buildlist.go b/src/cmd/go/internal/modload/buildlist.go
index 54ec4d23ebe08e..bd3fc3ec75713b 100644
--- a/src/cmd/go/internal/modload/buildlist.go
+++ b/src/cmd/go/internal/modload/buildlist.go
@@ -552,14 +552,14 @@ func (mg *ModuleGraph) allRootsSelected(loaderstate *State) bool {
 // Modules are loaded automatically (and lazily) in LoadPackages:
 // LoadModGraph need only be called if LoadPackages is not,
 // typically in commands that care about modules but no particular package.
-func LoadModGraph(ctx context.Context, goVersion string) (*ModuleGraph, error) {
-	rs, err := loadModFile(LoaderState, ctx, nil)
+func LoadModGraph(loaderstate *State, ctx context.Context, goVersion string) (*ModuleGraph, error) {
+	rs, err := loadModFile(loaderstate, ctx, nil)
 	if err != nil {
 		return nil, err
 	}
 
 	if goVersion != "" {
-		v, _ := rs.rootSelected(LoaderState, "go")
+		v, _ := rs.rootSelected(loaderstate, "go")
 		if gover.Compare(v, gover.GoStrictVersion) >= 0 && gover.Compare(goVersion, v) < 0 {
 			return nil, fmt.Errorf("requested Go version %s cannot load module graph (requires Go >= %s)", goVersion, v)
 		}
@@ -569,17 +569,17 @@ func LoadModGraph(ctx context.Context, goVersion string) (*ModuleGraph, error) {
 			// Use newRequirements instead of convertDepth because convertDepth
 			// also updates roots; here, we want to report the unmodified roots
 			// even though they may seem inconsistent.
-			rs = newRequirements(LoaderState, unpruned, rs.rootModules, rs.direct)
+			rs = newRequirements(loaderstate, unpruned, rs.rootModules, rs.direct)
 		}
 
-		return rs.Graph(LoaderState, ctx)
+		return rs.Graph(loaderstate, ctx)
 	}
 
-	rs, mg, err := expandGraph(LoaderState, ctx, rs)
+	rs, mg, err := expandGraph(loaderstate, ctx, rs)
 	if err != nil {
 		return nil, err
 	}
-	LoaderState.requirements = rs
+	loaderstate.requirements = rs
 	return mg, nil
 }
 
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 9182f60ee7b1bb..9b8e520d74a47b 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -1808,9 +1808,9 @@ type WriteOpts struct {
 }
 
 // WriteGoMod writes the current build list back to go.mod.
-func WriteGoMod(ctx context.Context, opts WriteOpts) error {
-	LoaderState.requirements = LoadModFile(LoaderState, ctx)
-	return commitRequirements(LoaderState, ctx, opts)
+func WriteGoMod(loaderstate *State, ctx context.Context, opts WriteOpts) error {
+	loaderstate.requirements = LoadModFile(loaderstate, ctx)
+	return commitRequirements(loaderstate, ctx, opts)
 }
 
 var errNoChange = errors.New("no update needed")
diff --git a/src/cmd/go/internal/workcmd/sync.go b/src/cmd/go/internal/workcmd/sync.go
index dfff0c29d227b1..7f45909de5c377 100644
--- a/src/cmd/go/internal/workcmd/sync.go
+++ b/src/cmd/go/internal/workcmd/sync.go
@@ -54,7 +54,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
 	}
 
-	_, err := modload.LoadModGraph(ctx, "")
+	_, err := modload.LoadModGraph(modload.LoaderState, ctx, "")
 	if err != nil {
 		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 	}
@@ -129,7 +129,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 				SilenceMissingStdImports: true,
 				SilencePackageErrors:     true,
 			}, "all")
-			modload.WriteGoMod(ctx, modload.WriteOpts{})
+			modload.WriteGoMod(modload.LoaderState, ctx, modload.WriteOpts{})
 		}
 		goV = gover.Max(goV, modload.LoaderState.MainModules.GoVersion(modload.LoaderState))
 	}

From 92aa3e9e98430ae48e3341b01434b5095f3b1c9e Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 1 Oct 2025 23:04:06 -0400
Subject: [PATCH 189/229] cmd/go: inject State parameter into `modcmd.runInit`

This command modifies the call tree starting at `modcmd.runInit` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modcmd
rf 'inject modload.LoaderState runInit'
cd ..
./rf-cleanup.zsh

Change-Id: Ie8bb8eb0edc2fabceafd9c41a2b11fe2a3532b73
Reviewed-on: https://go-review.googlesource.com/c/go/+/709983
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modcmd/init.go  |  2 +-
 src/cmd/go/internal/modload/init.go | 16 ++++++++--------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/cmd/go/internal/modcmd/init.go b/src/cmd/go/internal/modcmd/init.go
index 618c673bf86f24..32eb5d06f9ee23 100644
--- a/src/cmd/go/internal/modcmd/init.go
+++ b/src/cmd/go/internal/modcmd/init.go
@@ -44,5 +44,5 @@ func runInit(ctx context.Context, cmd *base.Command, args []string) {
 	}
 
 	modload.LoaderState.ForceUseModules = true
-	modload.CreateModFile(ctx, modPath) // does all the hard work
+	modload.CreateModFile(modload.LoaderState, ctx, modPath) // does all the hard work
 }
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 9b8e520d74a47b..bdc201bd94d498 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -1123,10 +1123,10 @@ func CheckReservedModulePath(path string) error {
 // translate it to go.mod directives. The resulting build list may not be
 // exactly the same as in the legacy configuration (for example, we can't get
 // packages at multiple versions from the same module).
-func CreateModFile(ctx context.Context, modPath string) {
+func CreateModFile(loaderstate *State, ctx context.Context, modPath string) {
 	modRoot := base.Cwd()
-	LoaderState.modRoots = []string{modRoot}
-	Init(LoaderState)
+	loaderstate.modRoots = []string{modRoot}
+	Init(loaderstate)
 	modFilePath := modFilePath(modRoot)
 	if _, err := fsys.Stat(modFilePath); err == nil {
 		base.Fatalf("go: %s already exists", modFilePath)
@@ -1162,16 +1162,16 @@ func CreateModFile(ctx context.Context, modPath string) {
 	fmt.Fprintf(os.Stderr, "go: creating new go.mod: module %s\n", modPath)
 	modFile := new(modfile.File)
 	modFile.AddModuleStmt(modPath)
-	LoaderState.MainModules = makeMainModules(LoaderState, []module.Version{modFile.Module.Mod}, []string{modRoot}, []*modfile.File{modFile}, []*modFileIndex{nil}, nil)
+	loaderstate.MainModules = makeMainModules(loaderstate, []module.Version{modFile.Module.Mod}, []string{modRoot}, []*modfile.File{modFile}, []*modFileIndex{nil}, nil)
 	addGoStmt(modFile, modFile.Module.Mod, gover.Local()) // Add the go directive before converted module requirements.
 
-	rs := requirementsFromModFiles(LoaderState, ctx, nil, []*modfile.File{modFile}, nil)
-	rs, err := updateRoots(LoaderState, ctx, rs.direct, rs, nil, nil, false)
+	rs := requirementsFromModFiles(loaderstate, ctx, nil, []*modfile.File{modFile}, nil)
+	rs, err := updateRoots(loaderstate, ctx, rs.direct, rs, nil, nil, false)
 	if err != nil {
 		base.Fatal(err)
 	}
-	LoaderState.requirements = rs
-	if err := commitRequirements(LoaderState, ctx, WriteOpts{}); err != nil {
+	loaderstate.requirements = rs
+	if err := commitRequirements(loaderstate, ctx, WriteOpts{}); err != nil {
 		base.Fatal(err)
 	}
 

From 0f820aca291dfd091c87c045147715cc1bf7266b Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 1 Oct 2025 23:18:10 -0400
Subject: [PATCH 190/229] cmd/go: inject State parameter into
 `modcmd.runVendor`

This command modifies the call tree starting at `modcmd.runVendor` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modcmd
rf 'inject modload.LoaderState runVendor'
cd ..
./rf-cleanup.zsh

Change-Id: I0572e165d291e34d212ded9a420871688b7915ad
Reviewed-on: https://go-review.googlesource.com/c/go/+/709984
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modcmd/vendor.go  | 44 +++++++++++++--------------
 src/cmd/go/internal/modget/get.go     |  4 +--
 src/cmd/go/internal/modload/init.go   |  8 ++---
 src/cmd/go/internal/workcmd/vendor.go |  2 +-
 4 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index 45d0aeff9c36de..c7be3899f3886f 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -70,15 +70,15 @@ func runVendor(ctx context.Context, cmd *base.Command, args []string) {
 	if modload.WorkFilePath(modload.LoaderState) != "" {
 		base.Fatalf("go: 'go mod vendor' cannot be run in workspace mode. Run 'go work vendor' to vendor the workspace or set 'GOWORK=off' to exit workspace mode.")
 	}
-	RunVendor(ctx, vendorE, vendorO, args)
+	RunVendor(modload.LoaderState, ctx, vendorE, vendorO, args)
 }
 
-func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string) {
+func RunVendor(loaderstate *modload.State, ctx context.Context, vendorE bool, vendorO string, args []string) {
 	if len(args) != 0 {
 		base.Fatalf("go: 'go mod vendor' accepts no arguments")
 	}
-	modload.LoaderState.ForceUseModules = true
-	modload.LoaderState.RootMode = modload.NeedRoot
+	loaderstate.ForceUseModules = true
+	loaderstate.RootMode = modload.NeedRoot
 
 	loadOpts := modload.PackageOpts{
 		Tags:                     imports.AnyTags(),
@@ -88,7 +88,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 		AllowErrors:              vendorE,
 		SilenceMissingStdImports: true,
 	}
-	_, pkgs := modload.LoadPackages(modload.LoaderState, ctx, loadOpts, "all")
+	_, pkgs := modload.LoadPackages(loaderstate, ctx, loadOpts, "all")
 
 	var vdir string
 	switch {
@@ -97,7 +97,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 	case vendorO != "":
 		vdir = filepath.Join(base.Cwd(), vendorO)
 	default:
-		vdir = filepath.Join(modload.VendorDir(modload.LoaderState))
+		vdir = filepath.Join(modload.VendorDir(loaderstate))
 	}
 	if err := os.RemoveAll(vdir); err != nil {
 		base.Fatal(err)
@@ -106,7 +106,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 	modpkgs := make(map[module.Version][]string)
 	for _, pkg := range pkgs {
 		m := modload.PackageModule(pkg)
-		if m.Path == "" || modload.LoaderState.MainModules.Contains(m.Path) {
+		if m.Path == "" || loaderstate.MainModules.Contains(m.Path) {
 			continue
 		}
 		modpkgs[m] = append(modpkgs[m], pkg)
@@ -116,13 +116,13 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 	includeAllReplacements := false
 	includeGoVersions := false
 	isExplicit := map[module.Version]bool{}
-	gv := modload.LoaderState.MainModules.GoVersion(modload.LoaderState)
-	if gover.Compare(gv, "1.14") >= 0 && (modload.FindGoWork(modload.LoaderState, base.Cwd()) != "" || modload.ModFile().Go != nil) {
+	gv := loaderstate.MainModules.GoVersion(loaderstate)
+	if gover.Compare(gv, "1.14") >= 0 && (modload.FindGoWork(loaderstate, base.Cwd()) != "" || modload.ModFile(loaderstate).Go != nil) {
 		// If the Go version is at least 1.14, annotate all explicit 'require' and
 		// 'replace' targets found in the go.mod file so that we can perform a
 		// stronger consistency check when -mod=vendor is set.
-		for _, m := range modload.LoaderState.MainModules.Versions() {
-			if modFile := modload.LoaderState.MainModules.ModFile(m); modFile != nil {
+		for _, m := range loaderstate.MainModules.Versions() {
+			if modFile := loaderstate.MainModules.ModFile(m); modFile != nil {
 				for _, r := range modFile.Require {
 					isExplicit[r.Mod] = true
 				}
@@ -156,20 +156,20 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 		w = io.MultiWriter(&buf, os.Stderr)
 	}
 
-	if modload.LoaderState.MainModules.WorkFile() != nil {
+	if loaderstate.MainModules.WorkFile() != nil {
 		fmt.Fprintf(w, "## workspace\n")
 	}
 
 	replacementWritten := make(map[module.Version]bool)
 	for _, m := range vendorMods {
-		replacement := modload.Replacement(modload.LoaderState, m)
+		replacement := modload.Replacement(loaderstate, m)
 		line := moduleLine(m, replacement)
 		replacementWritten[m] = true
 		io.WriteString(w, line)
 
 		goVersion := ""
 		if includeGoVersions {
-			goVersion = modload.ModuleInfo(modload.LoaderState, ctx, m.Path).GoVersion
+			goVersion = modload.ModuleInfo(loaderstate, ctx, m.Path).GoVersion
 		}
 		switch {
 		case isExplicit[m] && goVersion != "":
@@ -184,7 +184,7 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 		sort.Strings(pkgs)
 		for _, pkg := range pkgs {
 			fmt.Fprintf(w, "%s\n", pkg)
-			vendorPkg(vdir, pkg)
+			vendorPkg(loaderstate, vdir, pkg)
 		}
 	}
 
@@ -192,8 +192,8 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 		// Record unused and wildcard replacements at the end of the modules.txt file:
 		// without access to the complete build list, the consumer of the vendor
 		// directory can't otherwise determine that those replacements had no effect.
-		for _, m := range modload.LoaderState.MainModules.Versions() {
-			if workFile := modload.LoaderState.MainModules.WorkFile(); workFile != nil {
+		for _, m := range loaderstate.MainModules.Versions() {
+			if workFile := loaderstate.MainModules.WorkFile(); workFile != nil {
 				for _, r := range workFile.Replace {
 					if replacementWritten[r.Old] {
 						// We already recorded this replacement.
@@ -208,14 +208,14 @@ func RunVendor(ctx context.Context, vendorE bool, vendorO string, args []string)
 					}
 				}
 			}
-			if modFile := modload.LoaderState.MainModules.ModFile(m); modFile != nil {
+			if modFile := loaderstate.MainModules.ModFile(m); modFile != nil {
 				for _, r := range modFile.Replace {
 					if replacementWritten[r.Old] {
 						// We already recorded this replacement.
 						continue
 					}
 					replacementWritten[r.Old] = true
-					rNew := modload.Replacement(modload.LoaderState, r.Old)
+					rNew := modload.Replacement(loaderstate, r.Old)
 					if rNew == (module.Version{}) {
 						// There is no replacement. Don't try to write it.
 						continue
@@ -268,8 +268,8 @@ func moduleLine(m, r module.Version) string {
 	return b.String()
 }
 
-func vendorPkg(vdir, pkg string) {
-	src, realPath, _ := modload.Lookup(modload.LoaderState, "", false, pkg)
+func vendorPkg(loaderstate *modload.State, vdir, pkg string) {
+	src, realPath, _ := modload.Lookup(loaderstate, "", false, pkg)
 	if src == "" {
 		base.Errorf("internal error: no pkg for %s\n", pkg)
 		return
@@ -315,7 +315,7 @@ func vendorPkg(vdir, pkg string) {
 		}
 	}
 	var embedPatterns []string
-	if gover.Compare(modload.LoaderState.MainModules.GoVersion(modload.LoaderState), "1.22") >= 0 {
+	if gover.Compare(loaderstate.MainModules.GoVersion(loaderstate), "1.22") >= 0 {
 		embedPatterns = bp.EmbedPatterns
 	} else {
 		// Maintain the behavior of https://github.com/golang/go/issues/63473
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index b8018c04c987f4..8735dc4a59649c 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -410,7 +410,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	}
 
 	// Everything succeeded. Update go.mod.
-	oldReqs := reqsFromGoMod(modload.ModFile())
+	oldReqs := reqsFromGoMod(modload.ModFile(modload.LoaderState))
 
 	if err := modload.WriteGoMod(modload.LoaderState, ctx, opts); err != nil {
 		// A TooNewError can happen for 'go get go@newversion'
@@ -421,7 +421,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
 	}
 
-	newReqs := reqsFromGoMod(modload.ModFile())
+	newReqs := reqsFromGoMod(modload.ModFile(modload.LoaderState))
 	r.reportChanges(oldReqs, newReqs)
 
 	if gowork := modload.FindGoWork(modload.LoaderState, base.Cwd()); gowork != "" {
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index bdc201bd94d498..eeb6288f61a12e 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -314,11 +314,11 @@ const (
 // will be lost at the next call to WriteGoMod.
 // To make permanent changes to the require statements
 // in go.mod, edit it before loading.
-func ModFile() *modfile.File {
-	Init(LoaderState)
-	modFile := LoaderState.MainModules.ModFile(LoaderState.MainModules.mustGetSingleMainModule(LoaderState))
+func ModFile(loaderstate *State) *modfile.File {
+	Init(loaderstate)
+	modFile := loaderstate.MainModules.ModFile(loaderstate.MainModules.mustGetSingleMainModule(loaderstate))
 	if modFile == nil {
-		die(LoaderState)
+		die(loaderstate)
 	}
 	return modFile
 }
diff --git a/src/cmd/go/internal/workcmd/vendor.go b/src/cmd/go/internal/workcmd/vendor.go
index 36c1f7b522f9e7..f3f074c156c9b6 100644
--- a/src/cmd/go/internal/workcmd/vendor.go
+++ b/src/cmd/go/internal/workcmd/vendor.go
@@ -51,5 +51,5 @@ func runVendor(ctx context.Context, cmd *base.Command, args []string) {
 		base.Fatalf("go: no go.work file found\n\t(run 'go work init' first or specify path using GOWORK environment variable)")
 	}
 
-	modcmd.RunVendor(ctx, vendorE, vendorO, args)
+	modcmd.RunVendor(modload.LoaderState, ctx, vendorE, vendorO, args)
 }

From f859799ccf537bc5f506698ae2d1ce028b81c78c Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 1 Oct 2025 23:21:21 -0400
Subject: [PATCH 191/229] cmd/go: inject State parameter into
 `modcmd.runVerify`

This command modifies the call tree starting at `modcmd.runVerify` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modcmd
rf 'inject modload.LoaderState runVerify'
cd ..
./rf-cleanup.zsh

Change-Id: I5b3b4670a4e2d19375049e585035145d14248b40
Reviewed-on: https://go-review.googlesource.com/c/go/+/709985
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/go/internal/modcmd/verify.go | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/cmd/go/internal/modcmd/verify.go b/src/cmd/go/internal/modcmd/verify.go
index bf803fd2ebbaf5..358d7dd2030169 100644
--- a/src/cmd/go/internal/modcmd/verify.go
+++ b/src/cmd/go/internal/modcmd/verify.go
@@ -71,7 +71,7 @@ func runVerify(ctx context.Context, cmd *base.Command, args []string) {
 		errsChans[i] = errsc
 		mod := mod // use a copy to avoid data races
 		go func() {
-			errsc <- verifyMod(ctx, mod)
+			errsc <- verifyMod(modload.LoaderState, ctx, mod)
 			<-sem
 		}()
 	}
@@ -89,12 +89,12 @@ func runVerify(ctx context.Context, cmd *base.Command, args []string) {
 	}
 }
 
-func verifyMod(ctx context.Context, mod module.Version) []error {
+func verifyMod(loaderstate *modload.State, ctx context.Context, mod module.Version) []error {
 	if gover.IsToolchain(mod.Path) {
 		// "go" and "toolchain" have no disk footprint; nothing to verify.
 		return nil
 	}
-	if modload.LoaderState.MainModules.Contains(mod.Path) {
+	if loaderstate.MainModules.Contains(mod.Path) {
 		return nil
 	}
 	var errs []error

From 9769a61e6420a05685142fabfb0932abd1375e14 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 1 Oct 2025 17:45:25 -0400
Subject: [PATCH 192/229] cmd/go: inject State parameter into `modget.runGet`

This command modifies the call tree starting at `modget.runGet` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/modget
rf 'inject modload.LoaderState runGet'
cd ..
./rf-cleanup.zsh

Change-Id: Icafc5cff07c49809f5c199feec9ed7795536976c
Reviewed-on: https://go-review.googlesource.com/c/go/+/709981
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modget/get.go     | 232 +++++++++++++-------------
 src/cmd/go/internal/modget/query.go   |  10 +-
 src/cmd/go/internal/modload/init.go   |  20 +--
 src/cmd/go/internal/modload/search.go |  10 +-
 4 files changed, 136 insertions(+), 136 deletions(-)

diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go
index 8735dc4a59649c..466669f36e419a 100644
--- a/src/cmd/go/internal/modget/get.go
+++ b/src/cmd/go/internal/modget/get.go
@@ -323,7 +323,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 			"\tor run 'go help get' or 'go help install'.")
 	}
 
-	dropToolchain, queries := parseArgs(ctx, args)
+	dropToolchain, queries := parseArgs(modload.LoaderState, ctx, args)
 	opts := modload.WriteOpts{
 		DropToolchain: dropToolchain,
 	}
@@ -333,17 +333,17 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 		}
 	}
 
-	r := newResolver(ctx, queries)
-	r.performLocalQueries(ctx)
-	r.performPathQueries(ctx)
-	r.performToolQueries(ctx)
-	r.performWorkQueries(ctx)
+	r := newResolver(modload.LoaderState, ctx, queries)
+	r.performLocalQueries(modload.LoaderState, ctx)
+	r.performPathQueries(modload.LoaderState, ctx)
+	r.performToolQueries(modload.LoaderState, ctx)
+	r.performWorkQueries(modload.LoaderState, ctx)
 
 	for {
-		r.performWildcardQueries(ctx)
-		r.performPatternAllQueries(ctx)
+		r.performWildcardQueries(modload.LoaderState, ctx)
+		r.performPatternAllQueries(modload.LoaderState, ctx)
 
-		if changed := r.resolveQueries(ctx, queries); changed {
+		if changed := r.resolveQueries(modload.LoaderState, ctx, queries); changed {
 			// 'go get' arguments can be (and often are) package patterns rather than
 			// (just) modules. A package can be provided by any module with a prefix
 			// of its import path, and a wildcard can even match packages in modules
@@ -379,20 +379,20 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 		//
 		// - ambiguous import errors.
 		//   TODO(#27899): Try to resolve ambiguous import errors automatically.
-		upgrades := r.findAndUpgradeImports(ctx, queries)
-		if changed := r.applyUpgrades(ctx, upgrades); changed {
+		upgrades := r.findAndUpgradeImports(modload.LoaderState, ctx, queries)
+		if changed := r.applyUpgrades(modload.LoaderState, ctx, upgrades); changed {
 			continue
 		}
 
-		r.findMissingWildcards(ctx)
-		if changed := r.resolveQueries(ctx, r.wildcardQueries); changed {
+		r.findMissingWildcards(modload.LoaderState, ctx)
+		if changed := r.resolveQueries(modload.LoaderState, ctx, r.wildcardQueries); changed {
 			continue
 		}
 
 		break
 	}
 
-	r.checkWildcardVersions(ctx)
+	r.checkWildcardVersions(modload.LoaderState, ctx)
 
 	var pkgPatterns []string
 	for _, q := range queries {
@@ -403,10 +403,10 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 
 	// If a workspace applies, checkPackageProblems will switch to the workspace
 	// using modload.EnterWorkspace when doing the final load, and then switch back.
-	r.checkPackageProblems(ctx, pkgPatterns)
+	r.checkPackageProblems(modload.LoaderState, ctx, pkgPatterns)
 
 	if *getTool {
-		updateTools(ctx, queries, &opts)
+		updateTools(modload.LoaderState, ctx, queries, &opts)
 	}
 
 	// Everything succeeded. Update go.mod.
@@ -432,7 +432,7 @@ func runGet(ctx context.Context, cmd *base.Command, args []string) {
 	}
 }
 
-func updateTools(ctx context.Context, queries []*query, opts *modload.WriteOpts) {
+func updateTools(loaderstate *modload.State, ctx context.Context, queries []*query, opts *modload.WriteOpts) {
 	pkgOpts := modload.PackageOpts{
 		VendorModulesInGOROOTSrc: true,
 		LoadTests:                *getT,
@@ -448,7 +448,7 @@ func updateTools(ctx context.Context, queries []*query, opts *modload.WriteOpts)
 		patterns = append(patterns, q.pattern)
 	}
 
-	matches, _ := modload.LoadPackages(modload.LoaderState, ctx, pkgOpts, patterns...)
+	matches, _ := modload.LoadPackages(loaderstate, ctx, pkgOpts, patterns...)
 	for i, m := range matches {
 		if queries[i].version == "none" {
 			opts.DropTools = append(opts.DropTools, m.Pkgs...)
@@ -462,11 +462,11 @@ func updateTools(ctx context.Context, queries []*query, opts *modload.WriteOpts)
 //
 // The command-line arguments are of the form path@version or simply path, with
 // implicit @upgrade. path@none is "downgrade away".
-func parseArgs(ctx context.Context, rawArgs []string) (dropToolchain bool, queries []*query) {
+func parseArgs(loaderstate *modload.State, ctx context.Context, rawArgs []string) (dropToolchain bool, queries []*query) {
 	defer base.ExitIfErrors()
 
 	for _, arg := range search.CleanPatterns(rawArgs) {
-		q, err := newQuery(arg)
+		q, err := newQuery(loaderstate, arg)
 		if err != nil {
 			base.Error(err)
 			continue
@@ -553,12 +553,12 @@ type matchInModuleKey struct {
 	m       module.Version
 }
 
-func newResolver(ctx context.Context, queries []*query) *resolver {
+func newResolver(loaderstate *modload.State, ctx context.Context, queries []*query) *resolver {
 	// LoadModGraph also sets modload.Target, which is needed by various resolver
 	// methods.
-	mg, err := modload.LoadModGraph(modload.LoaderState, ctx, "")
+	mg, err := modload.LoadModGraph(loaderstate, ctx, "")
 	if err != nil {
-		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
+		toolchain.SwitchOrFatal(loaderstate, ctx, err)
 	}
 
 	buildList := mg.BuildList()
@@ -574,7 +574,7 @@ func newResolver(ctx context.Context, queries []*query) *resolver {
 		buildListVersion: initialVersion,
 		initialVersion:   initialVersion,
 		nonesByPath:      map[string]*query{},
-		workspace:        loadWorkspace(modload.FindGoWork(modload.LoaderState, base.Cwd())),
+		workspace:        loadWorkspace(modload.FindGoWork(loaderstate, base.Cwd())),
 	}
 
 	for _, q := range queries {
@@ -643,9 +643,9 @@ func (r *resolver) noneForPath(mPath string) (nq *query, found bool) {
 
 // queryModule wraps modload.Query, substituting r.checkAllowedOr to decide
 // allowed versions.
-func (r *resolver) queryModule(ctx context.Context, mPath, query string, selected func(string) string) (module.Version, error) {
+func (r *resolver) queryModule(loaderstate *modload.State, ctx context.Context, mPath, query string, selected func(string) string) (module.Version, error) {
 	current := r.initialSelected(mPath)
-	rev, err := modload.Query(modload.LoaderState, ctx, mPath, query, current, r.checkAllowedOr(query, selected))
+	rev, err := modload.Query(loaderstate, ctx, mPath, query, current, r.checkAllowedOr(loaderstate, query, selected))
 	if err != nil {
 		return module.Version{}, err
 	}
@@ -654,8 +654,8 @@ func (r *resolver) queryModule(ctx context.Context, mPath, query string, selecte
 
 // queryPackages wraps modload.QueryPackage, substituting r.checkAllowedOr to
 // decide allowed versions.
-func (r *resolver) queryPackages(ctx context.Context, pattern, query string, selected func(string) string) (pkgMods []module.Version, err error) {
-	results, err := modload.QueryPackages(modload.LoaderState, ctx, pattern, query, selected, r.checkAllowedOr(query, selected))
+func (r *resolver) queryPackages(loaderstate *modload.State, ctx context.Context, pattern, query string, selected func(string) string) (pkgMods []module.Version, err error) {
+	results, err := modload.QueryPackages(loaderstate, ctx, pattern, query, selected, r.checkAllowedOr(loaderstate, query, selected))
 	if len(results) > 0 {
 		pkgMods = make([]module.Version, 0, len(results))
 		for _, qr := range results {
@@ -667,8 +667,8 @@ func (r *resolver) queryPackages(ctx context.Context, pattern, query string, sel
 
 // queryPattern wraps modload.QueryPattern, substituting r.checkAllowedOr to
 // decide allowed versions.
-func (r *resolver) queryPattern(ctx context.Context, pattern, query string, selected func(string) string) (pkgMods []module.Version, mod module.Version, err error) {
-	results, modOnly, err := modload.QueryPattern(modload.LoaderState, ctx, pattern, query, selected, r.checkAllowedOr(query, selected))
+func (r *resolver) queryPattern(loaderstate *modload.State, ctx context.Context, pattern, query string, selected func(string) string) (pkgMods []module.Version, mod module.Version, err error) {
+	results, modOnly, err := modload.QueryPattern(loaderstate, ctx, pattern, query, selected, r.checkAllowedOr(loaderstate, query, selected))
 	if len(results) > 0 {
 		pkgMods = make([]module.Version, 0, len(results))
 		for _, qr := range results {
@@ -683,7 +683,7 @@ func (r *resolver) queryPattern(ctx context.Context, pattern, query string, sele
 
 // checkAllowedOr is like modload.CheckAllowed, but it always allows the requested
 // and current versions (even if they are retracted or otherwise excluded).
-func (r *resolver) checkAllowedOr(requested string, selected func(string) string) modload.AllowedFunc {
+func (r *resolver) checkAllowedOr(loaderstate *modload.State, requested string, selected func(string) string) modload.AllowedFunc {
 	return func(ctx context.Context, m module.Version) error {
 		if m.Version == requested {
 			return modload.CheckExclusions(ctx, m)
@@ -696,9 +696,9 @@ func (r *resolver) checkAllowedOr(requested string, selected func(string) string
 }
 
 // matchInModule is a caching wrapper around modload.MatchInModule.
-func (r *resolver) matchInModule(ctx context.Context, pattern string, m module.Version) (packages []string, err error) {
+func (r *resolver) matchInModule(loaderstate *modload.State, ctx context.Context, pattern string, m module.Version) (packages []string, err error) {
 	return r.matchInModuleCache.Do(matchInModuleKey{pattern, m}, func() ([]string, error) {
-		match := modload.MatchInModule(ctx, pattern, m, imports.AnyTags())
+		match := modload.MatchInModule(loaderstate, ctx, pattern, m, imports.AnyTags())
 		if len(match.Errs) > 0 {
 			return match.Pkgs, match.Errs[0]
 		}
@@ -714,15 +714,15 @@ func (r *resolver) matchInModule(ctx context.Context, pattern string, m module.V
 // modules second. However, no module exists at version "none", and therefore no
 // package exists at that version either: we know that the argument cannot match
 // any packages, and thus it must match modules instead.
-func (r *resolver) queryNone(ctx context.Context, q *query) {
+func (r *resolver) queryNone(loaderstate *modload.State, ctx context.Context, q *query) {
 	if search.IsMetaPackage(q.pattern) {
 		panic(fmt.Sprintf("internal error: queryNone called with pattern %q", q.pattern))
 	}
 
 	if !q.isWildcard() {
 		q.pathOnce(q.pattern, func() pathSet {
-			hasModRoot := modload.HasModRoot(modload.LoaderState)
-			if hasModRoot && modload.LoaderState.MainModules.Contains(q.pattern) {
+			hasModRoot := modload.HasModRoot(loaderstate)
+			if hasModRoot && loaderstate.MainModules.Contains(q.pattern) {
 				v := module.Version{Path: q.pattern}
 				// The user has explicitly requested to downgrade their own module to
 				// version "none". This is not an entirely unreasonable request: it
@@ -746,7 +746,7 @@ func (r *resolver) queryNone(ctx context.Context, q *query) {
 			continue
 		}
 		q.pathOnce(curM.Path, func() pathSet {
-			if modload.HasModRoot(modload.LoaderState) && curM.Version == "" && modload.LoaderState.MainModules.Contains(curM.Path) {
+			if modload.HasModRoot(loaderstate) && curM.Version == "" && loaderstate.MainModules.Contains(curM.Path) {
 				return errSet(&modload.QueryMatchesMainModulesError{MainModules: []module.Version{curM}, Pattern: q.pattern, Query: q.version})
 			}
 			return pathSet{mod: module.Version{Path: curM.Path, Version: "none"}}
@@ -754,7 +754,7 @@ func (r *resolver) queryNone(ctx context.Context, q *query) {
 	}
 }
 
-func (r *resolver) performLocalQueries(ctx context.Context) {
+func (r *resolver) performLocalQueries(loaderstate *modload.State, ctx context.Context) {
 	for _, q := range r.localQueries {
 		q.pathOnce(q.pattern, func() pathSet {
 			absDetail := ""
@@ -766,13 +766,13 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 
 			// Absolute paths like C:\foo and relative paths like ../foo... are
 			// restricted to matching packages in the main module.
-			pkgPattern, mainModule := modload.LoaderState.MainModules.DirImportPath(modload.LoaderState, ctx, q.pattern)
+			pkgPattern, mainModule := loaderstate.MainModules.DirImportPath(loaderstate, ctx, q.pattern)
 			if pkgPattern == "." {
-				modload.MustHaveModRoot(modload.LoaderState)
-				versions := modload.LoaderState.MainModules.Versions()
+				modload.MustHaveModRoot(loaderstate)
+				versions := loaderstate.MainModules.Versions()
 				modRoots := make([]string, 0, len(versions))
 				for _, m := range versions {
-					modRoots = append(modRoots, modload.LoaderState.MainModules.ModRoot(m))
+					modRoots = append(modRoots, loaderstate.MainModules.ModRoot(m))
 				}
 				var plural string
 				if len(modRoots) != 1 {
@@ -781,7 +781,7 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 				return errSet(fmt.Errorf("%s%s is not within module%s rooted at %s", q.pattern, absDetail, plural, strings.Join(modRoots, ", ")))
 			}
 
-			match := modload.MatchInModule(ctx, pkgPattern, mainModule, imports.AnyTags())
+			match := modload.MatchInModule(loaderstate, ctx, pkgPattern, mainModule, imports.AnyTags())
 			if len(match.Errs) > 0 {
 				return pathSet{err: match.Errs[0]}
 			}
@@ -791,8 +791,8 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 					return errSet(fmt.Errorf("no package to get in current directory"))
 				}
 				if !q.isWildcard() {
-					modload.MustHaveModRoot(modload.LoaderState)
-					return errSet(fmt.Errorf("%s%s is not a package in module rooted at %s", q.pattern, absDetail, modload.LoaderState.MainModules.ModRoot(mainModule)))
+					modload.MustHaveModRoot(loaderstate)
+					return errSet(fmt.Errorf("%s%s is not a package in module rooted at %s", q.pattern, absDetail, loaderstate.MainModules.ModRoot(mainModule)))
 				}
 				search.WarnUnmatched([]*search.Match{match})
 				return pathSet{}
@@ -811,14 +811,14 @@ func (r *resolver) performLocalQueries(ctx context.Context) {
 // of modules may be expanded by other queries, so wildcard queries need to be
 // re-evaluated whenever a potentially-matching module path is added to the
 // build list.
-func (r *resolver) performWildcardQueries(ctx context.Context) {
+func (r *resolver) performWildcardQueries(loaderstate *modload.State, ctx context.Context) {
 	for _, q := range r.wildcardQueries {
 		q := q
 		r.work.Add(func() {
 			if q.version == "none" {
-				r.queryNone(ctx, q)
+				r.queryNone(loaderstate, ctx, q)
 			} else {
-				r.queryWildcard(ctx, q)
+				r.queryWildcard(loaderstate, ctx, q)
 			}
 		})
 	}
@@ -830,7 +830,7 @@ func (r *resolver) performWildcardQueries(ctx context.Context) {
 //   - that module exists at some version matching q.version, and
 //   - either the module path itself matches q.pattern, or some package within
 //     the module at q.version matches q.pattern.
-func (r *resolver) queryWildcard(ctx context.Context, q *query) {
+func (r *resolver) queryWildcard(loaderstate *modload.State, ctx context.Context, q *query) {
 	// For wildcard patterns, modload.QueryPattern only identifies modules
 	// matching the prefix of the path before the wildcard. However, the build
 	// list may already contain other modules with matching packages, and we
@@ -848,7 +848,7 @@ func (r *resolver) queryWildcard(ctx context.Context, q *query) {
 				return pathSet{}
 			}
 
-			if modload.LoaderState.MainModules.Contains(curM.Path) && !versionOkForMainModule(q.version) {
+			if loaderstate.MainModules.Contains(curM.Path) && !versionOkForMainModule(q.version) {
 				if q.matchesPath(curM.Path) {
 					return errSet(&modload.QueryMatchesMainModulesError{
 						MainModules: []module.Version{curM},
@@ -857,7 +857,7 @@ func (r *resolver) queryWildcard(ctx context.Context, q *query) {
 					})
 				}
 
-				packages, err := r.matchInModule(ctx, q.pattern, curM)
+				packages, err := r.matchInModule(loaderstate, ctx, q.pattern, curM)
 				if err != nil {
 					return errSet(err)
 				}
@@ -869,10 +869,10 @@ func (r *resolver) queryWildcard(ctx context.Context, q *query) {
 					})
 				}
 
-				return r.tryWildcard(ctx, q, curM)
+				return r.tryWildcard(loaderstate, ctx, q, curM)
 			}
 
-			m, err := r.queryModule(ctx, curM.Path, q.version, r.initialSelected)
+			m, err := r.queryModule(loaderstate, ctx, curM.Path, q.version, r.initialSelected)
 			if err != nil {
 				if !isNoSuchModuleVersion(err) {
 					// We can't tell whether a matching version exists.
@@ -894,7 +894,7 @@ func (r *resolver) queryWildcard(ctx context.Context, q *query) {
 				return pathSet{}
 			}
 
-			return r.tryWildcard(ctx, q, m)
+			return r.tryWildcard(loaderstate, ctx, q, m)
 		})
 	}
 
@@ -905,9 +905,9 @@ func (r *resolver) queryWildcard(ctx context.Context, q *query) {
 
 // tryWildcard returns a pathSet for module m matching query q.
 // If m does not actually match q, tryWildcard returns an empty pathSet.
-func (r *resolver) tryWildcard(ctx context.Context, q *query, m module.Version) pathSet {
+func (r *resolver) tryWildcard(loaderstate *modload.State, ctx context.Context, q *query, m module.Version) pathSet {
 	mMatches := q.matchesPath(m.Path)
-	packages, err := r.matchInModule(ctx, q.pattern, m)
+	packages, err := r.matchInModule(loaderstate, ctx, q.pattern, m)
 	if err != nil {
 		return errSet(err)
 	}
@@ -922,14 +922,14 @@ func (r *resolver) tryWildcard(ctx context.Context, q *query, m module.Version)
 
 // findMissingWildcards adds a candidate set for each query in r.wildcardQueries
 // that has not yet resolved to any version containing packages.
-func (r *resolver) findMissingWildcards(ctx context.Context) {
+func (r *resolver) findMissingWildcards(loaderstate *modload.State, ctx context.Context) {
 	for _, q := range r.wildcardQueries {
 		if q.version == "none" || q.matchesPackages {
 			continue // q is not “missing”
 		}
 		r.work.Add(func() {
 			q.pathOnce(q.pattern, func() pathSet {
-				pkgMods, mod, err := r.queryPattern(ctx, q.pattern, q.version, r.initialSelected)
+				pkgMods, mod, err := r.queryPattern(loaderstate, ctx, q.pattern, q.version, r.initialSelected)
 				if err != nil {
 					if isNoSuchPackageVersion(err) && len(q.resolved) > 0 {
 						// q already resolved one or more modules but matches no packages.
@@ -950,7 +950,7 @@ func (r *resolver) findMissingWildcards(ctx context.Context) {
 // checkWildcardVersions reports an error if any module in the build list has a
 // path (or contains a package) matching a query with a wildcard pattern, but
 // has a selected version that does *not* match the query.
-func (r *resolver) checkWildcardVersions(ctx context.Context) {
+func (r *resolver) checkWildcardVersions(loaderstate *modload.State, ctx context.Context) {
 	defer base.ExitIfErrors()
 
 	for _, q := range r.wildcardQueries {
@@ -959,7 +959,7 @@ func (r *resolver) checkWildcardVersions(ctx context.Context) {
 				continue
 			}
 			if !q.matchesPath(curM.Path) {
-				packages, err := r.matchInModule(ctx, q.pattern, curM)
+				packages, err := r.matchInModule(loaderstate, ctx, q.pattern, curM)
 				if len(packages) == 0 {
 					if err != nil {
 						reportError(q, err)
@@ -968,7 +968,7 @@ func (r *resolver) checkWildcardVersions(ctx context.Context) {
 				}
 			}
 
-			rev, err := r.queryModule(ctx, curM.Path, q.version, r.initialSelected)
+			rev, err := r.queryModule(loaderstate, ctx, curM.Path, q.version, r.initialSelected)
 			if err != nil {
 				reportError(q, err)
 				continue
@@ -979,7 +979,7 @@ func (r *resolver) checkWildcardVersions(ctx context.Context) {
 
 			if !q.matchesPath(curM.Path) {
 				m := module.Version{Path: curM.Path, Version: rev.Version}
-				packages, err := r.matchInModule(ctx, q.pattern, m)
+				packages, err := r.matchInModule(loaderstate, ctx, q.pattern, m)
 				if err != nil {
 					reportError(q, err)
 					continue
@@ -1013,14 +1013,14 @@ func (r *resolver) checkWildcardVersions(ctx context.Context) {
 // The candidate packages and modules for path literals depend only on the
 // initial build list, not the current build list, so we only need to query path
 // literals once.
-func (r *resolver) performPathQueries(ctx context.Context) {
+func (r *resolver) performPathQueries(loaderstate *modload.State, ctx context.Context) {
 	for _, q := range r.pathQueries {
 		q := q
 		r.work.Add(func() {
 			if q.version == "none" {
-				r.queryNone(ctx, q)
+				r.queryNone(loaderstate, ctx, q)
 			} else {
-				r.queryPath(ctx, q)
+				r.queryPath(loaderstate, ctx, q)
 			}
 		})
 	}
@@ -1031,7 +1031,7 @@ func (r *resolver) performPathQueries(ctx context.Context) {
 // The candidate set consists of all modules that could provide q.pattern
 // and have a version matching q, plus (if it exists) the module whose path
 // is itself q.pattern (at a matching version).
-func (r *resolver) queryPath(ctx context.Context, q *query) {
+func (r *resolver) queryPath(loaderstate *modload.State, ctx context.Context, q *query) {
 	q.pathOnce(q.pattern, func() pathSet {
 		if search.IsMetaPackage(q.pattern) || q.isWildcard() {
 			panic(fmt.Sprintf("internal error: queryPath called with pattern %q", q.pattern))
@@ -1042,7 +1042,7 @@ func (r *resolver) queryPath(ctx context.Context, q *query) {
 
 		if search.IsStandardImportPath(q.pattern) {
 			stdOnly := module.Version{}
-			packages, _ := r.matchInModule(ctx, q.pattern, stdOnly)
+			packages, _ := r.matchInModule(loaderstate, ctx, q.pattern, stdOnly)
 			if len(packages) > 0 {
 				if q.rawVersion != "" {
 					return errSet(fmt.Errorf("can't request explicit version %q of standard library package %s", q.version, q.pattern))
@@ -1053,7 +1053,7 @@ func (r *resolver) queryPath(ctx context.Context, q *query) {
 			}
 		}
 
-		pkgMods, mod, err := r.queryPattern(ctx, q.pattern, q.version, r.initialSelected)
+		pkgMods, mod, err := r.queryPattern(loaderstate, ctx, q.pattern, q.version, r.initialSelected)
 		if err != nil {
 			return errSet(err)
 		}
@@ -1063,11 +1063,11 @@ func (r *resolver) queryPath(ctx context.Context, q *query) {
 
 // performToolQueries populates the candidates for each query whose
 // pattern is "tool".
-func (r *resolver) performToolQueries(ctx context.Context) {
+func (r *resolver) performToolQueries(loaderstate *modload.State, ctx context.Context) {
 	for _, q := range r.toolQueries {
-		for tool := range modload.LoaderState.MainModules.Tools() {
+		for tool := range loaderstate.MainModules.Tools() {
 			q.pathOnce(tool, func() pathSet {
-				pkgMods, err := r.queryPackages(ctx, tool, q.version, r.initialSelected)
+				pkgMods, err := r.queryPackages(loaderstate, ctx, tool, q.version, r.initialSelected)
 				return pathSet{pkgMods: pkgMods, err: err}
 			})
 		}
@@ -1076,22 +1076,22 @@ func (r *resolver) performToolQueries(ctx context.Context) {
 
 // performWorkQueries populates the candidates for each query whose pattern is "work".
 // The candidate module to resolve the work pattern is exactly the single main module.
-func (r *resolver) performWorkQueries(ctx context.Context) {
+func (r *resolver) performWorkQueries(loaderstate *modload.State, ctx context.Context) {
 	for _, q := range r.workQueries {
 		q.pathOnce(q.pattern, func() pathSet {
 			// TODO(matloob): Maybe export MainModules.mustGetSingleMainModule and call that.
 			// There are a few other places outside the modload package where we expect
 			// a single main module.
-			if len(modload.LoaderState.MainModules.Versions()) != 1 {
+			if len(loaderstate.MainModules.Versions()) != 1 {
 				panic("internal error: number of main modules is not exactly one in resolution phase of go get")
 			}
-			mainModule := modload.LoaderState.MainModules.Versions()[0]
+			mainModule := loaderstate.MainModules.Versions()[0]
 
 			// We know what the result is going to be, assuming the main module is not
 			// empty, (it's the main module itself) but first check to see that there
 			// are packages in the main module, so that if there aren't any, we can
 			// return the expected warning that the pattern matched no packages.
-			match := modload.MatchInModule(ctx, q.pattern, mainModule, imports.AnyTags())
+			match := modload.MatchInModule(loaderstate, ctx, q.pattern, mainModule, imports.AnyTags())
 			if len(match.Errs) > 0 {
 				return pathSet{err: match.Errs[0]}
 			}
@@ -1113,7 +1113,7 @@ func (r *resolver) performWorkQueries(ctx context.Context) {
 // know which candidate is selected — and that selection may depend on the
 // results of other queries. We need to re-evaluate the "all" queries whenever
 // the module for one or more packages in "all" are resolved.
-func (r *resolver) performPatternAllQueries(ctx context.Context) {
+func (r *resolver) performPatternAllQueries(loaderstate *modload.State, ctx context.Context) {
 	if len(r.patternAllQueries) == 0 {
 		return
 	}
@@ -1122,7 +1122,7 @@ func (r *resolver) performPatternAllQueries(ctx context.Context) {
 		versionOk = true
 		for _, q := range r.patternAllQueries {
 			q.pathOnce(path, func() pathSet {
-				pkgMods, err := r.queryPackages(ctx, path, q.version, r.initialSelected)
+				pkgMods, err := r.queryPackages(loaderstate, ctx, path, q.version, r.initialSelected)
 				if len(pkgMods) != 1 || pkgMods[0] != m {
 					// There are candidates other than m for the given path, so we can't
 					// be certain that m will actually be the module selected to provide
@@ -1137,7 +1137,7 @@ func (r *resolver) performPatternAllQueries(ctx context.Context) {
 		return versionOk
 	}
 
-	r.loadPackages(ctx, []string{"all"}, findPackage)
+	r.loadPackages(loaderstate, ctx, []string{"all"}, findPackage)
 
 	// Since we built up the candidate lists concurrently, they may be in a
 	// nondeterministic order. We want 'go get' to be fully deterministic,
@@ -1157,7 +1157,7 @@ func (r *resolver) performPatternAllQueries(ctx context.Context) {
 // If the getU flag ("-u") is set, findAndUpgradeImports also returns a
 // pathSet for each module that is not constrained by any other
 // command-line argument and has an available matching upgrade.
-func (r *resolver) findAndUpgradeImports(ctx context.Context, queries []*query) (upgrades []pathSet) {
+func (r *resolver) findAndUpgradeImports(loaderstate *modload.State, ctx context.Context, queries []*query) (upgrades []pathSet) {
 	patterns := make([]string, 0, len(queries))
 	for _, q := range queries {
 		if q.matchesPackages {
@@ -1198,7 +1198,7 @@ func (r *resolver) findAndUpgradeImports(ctx context.Context, queries []*query)
 		// 	- The "-u" flag, unlike other arguments, does not cause version
 		// 	  conflicts with other queries. (The other query always wins.)
 
-		pkgMods, err := r.queryPackages(ctx, path, version, r.selected)
+		pkgMods, err := r.queryPackages(loaderstate, ctx, path, version, r.selected)
 		for _, u := range pkgMods {
 			if u == m {
 				// The selected package version is already upgraded appropriately; there
@@ -1229,7 +1229,7 @@ func (r *resolver) findAndUpgradeImports(ctx context.Context, queries []*query)
 		return false
 	}
 
-	r.loadPackages(ctx, patterns, findPackage)
+	r.loadPackages(loaderstate, ctx, patterns, findPackage)
 
 	// Since we built up the candidate lists concurrently, they may be in a
 	// nondeterministic order. We want 'go get' to be fully deterministic,
@@ -1253,14 +1253,14 @@ func (r *resolver) findAndUpgradeImports(ctx context.Context, queries []*query)
 // loadPackages also invokes the findPackage function for each imported package
 // that is neither present in the standard library nor in any module in the
 // build list.
-func (r *resolver) loadPackages(ctx context.Context, patterns []string, findPackage func(ctx context.Context, path string, m module.Version) (versionOk bool)) {
+func (r *resolver) loadPackages(loaderstate *modload.State, ctx context.Context, patterns []string, findPackage func(ctx context.Context, path string, m module.Version) (versionOk bool)) {
 	opts := modload.PackageOpts{
 		Tags:                     imports.AnyTags(),
 		VendorModulesInGOROOTSrc: true,
 		LoadTests:                *getT,
 		AssumeRootsImported:      true, // After 'go get foo', imports of foo should build.
 		SilencePackageErrors:     true, // May be fixed by subsequent upgrades or downgrades.
-		Switcher:                 toolchain.NewSwitcher(modload.LoaderState),
+		Switcher:                 toolchain.NewSwitcher(loaderstate),
 	}
 
 	opts.AllowPackage = func(ctx context.Context, path string, m module.Version) error {
@@ -1275,13 +1275,13 @@ func (r *resolver) loadPackages(ctx context.Context, patterns []string, findPack
 		return nil
 	}
 
-	_, pkgs := modload.LoadPackages(modload.LoaderState, ctx, opts, patterns...)
+	_, pkgs := modload.LoadPackages(loaderstate, ctx, opts, patterns...)
 	for _, pkgPath := range pkgs {
 		const (
 			parentPath  = ""
 			parentIsStd = false
 		)
-		_, _, err := modload.Lookup(modload.LoaderState, parentPath, parentIsStd, pkgPath)
+		_, _, err := modload.Lookup(loaderstate, parentPath, parentIsStd, pkgPath)
 		if err == nil {
 			continue
 		}
@@ -1327,7 +1327,7 @@ var errVersionChange = errors.New("version change needed")
 //
 // If all pathSets are resolved without any changes to the build list,
 // resolveQueries returns with changed=false.
-func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (changed bool) {
+func (r *resolver) resolveQueries(loaderstate *modload.State, ctx context.Context, queries []*query) (changed bool) {
 	defer base.ExitIfErrors()
 
 	// Note: this is O(N²) with the number of pathSets in the worst case.
@@ -1346,7 +1346,7 @@ func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (change
 
 		// If we found modules that were too new, find the max of the required versions
 		// and then try to switch to a newer toolchain.
-		sw := toolchain.NewSwitcher(modload.LoaderState)
+		sw := toolchain.NewSwitcher(loaderstate)
 		for _, q := range queries {
 			for _, cs := range q.candidates {
 				sw.Error(cs.err)
@@ -1371,7 +1371,7 @@ func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (change
 					continue
 				}
 
-				filtered, isPackage, m, unique := r.disambiguate(cs)
+				filtered, isPackage, m, unique := r.disambiguate(loaderstate, cs)
 				if !unique {
 					unresolved = append(unresolved, filtered)
 					continue
@@ -1385,7 +1385,7 @@ func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (change
 				if isPackage {
 					q.matchesPackages = true
 				}
-				r.resolve(q, m)
+				r.resolve(loaderstate, q, m)
 				resolved++
 			}
 
@@ -1399,7 +1399,7 @@ func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (change
 	}
 
 	if resolved > 0 {
-		if changed = r.updateBuildList(ctx, nil); changed {
+		if changed = r.updateBuildList(loaderstate, ctx, nil); changed {
 			// The build list has changed, so disregard any remaining ambiguous queries:
 			// they might now be determined by requirements in the build list, which we
 			// would prefer to use instead of arbitrary versions.
@@ -1421,12 +1421,12 @@ func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (change
 			if isPackage {
 				q.matchesPackages = true
 			}
-			r.resolve(q, m)
+			r.resolve(loaderstate, q, m)
 			resolvedArbitrarily++
 		}
 	}
 	if resolvedArbitrarily > 0 {
-		changed = r.updateBuildList(ctx, nil)
+		changed = r.updateBuildList(loaderstate, ctx, nil)
 	}
 	return changed
 }
@@ -1442,7 +1442,7 @@ func (r *resolver) resolveQueries(ctx context.Context, queries []*query) (change
 //
 // If all pathSets are resolved without any changes to the build list,
 // applyUpgrades returns with changed=false.
-func (r *resolver) applyUpgrades(ctx context.Context, upgrades []pathSet) (changed bool) {
+func (r *resolver) applyUpgrades(loaderstate *modload.State, ctx context.Context, upgrades []pathSet) (changed bool) {
 	defer base.ExitIfErrors()
 
 	// Arbitrarily add a "latest" version that provides each missing package, but
@@ -1455,7 +1455,7 @@ func (r *resolver) applyUpgrades(ctx context.Context, upgrades []pathSet) (chang
 			continue
 		}
 
-		filtered, _, m, unique := r.disambiguate(cs)
+		filtered, _, m, unique := r.disambiguate(loaderstate, cs)
 		if !unique {
 			_, m = r.chooseArbitrarily(filtered)
 		}
@@ -1468,7 +1468,7 @@ func (r *resolver) applyUpgrades(ctx context.Context, upgrades []pathSet) (chang
 	}
 	base.ExitIfErrors()
 
-	changed = r.updateBuildList(ctx, tentative)
+	changed = r.updateBuildList(loaderstate, ctx, tentative)
 	return changed
 }
 
@@ -1482,7 +1482,7 @@ func (r *resolver) applyUpgrades(ctx context.Context, upgrades []pathSet) (chang
 // In the vast majority of cases, we expect only one module per pathSet,
 // but we want to give some minimal additional tools so that users can add an
 // extra argument or two on the command line to resolve simple ambiguities.
-func (r *resolver) disambiguate(cs pathSet) (filtered pathSet, isPackage bool, m module.Version, unique bool) {
+func (r *resolver) disambiguate(loaderstate *modload.State, cs pathSet) (filtered pathSet, isPackage bool, m module.Version, unique bool) {
 	if len(cs.pkgMods) == 0 && cs.mod.Path == "" {
 		panic("internal error: resolveIfUnambiguous called with empty pathSet")
 	}
@@ -1494,7 +1494,7 @@ func (r *resolver) disambiguate(cs pathSet) (filtered pathSet, isPackage bool, m
 			continue
 		}
 
-		if modload.LoaderState.MainModules.Contains(m.Path) {
+		if loaderstate.MainModules.Contains(m.Path) {
 			if m.Version == "" {
 				return pathSet{}, true, m, true
 			}
@@ -1599,7 +1599,7 @@ func (r *resolver) chooseArbitrarily(cs pathSet) (isPackage bool, m module.Versi
 // We skip missing-package errors earlier in the process, since we want to
 // resolve pathSets ourselves, but at that point, we don't have enough context
 // to log the package-import chains leading to each error.
-func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []string) {
+func (r *resolver) checkPackageProblems(loaderstate *modload.State, ctx context.Context, pkgPatterns []string) {
 	defer base.ExitIfErrors()
 
 	// Enter workspace mode, if the current main module would belong to it, when
@@ -1610,16 +1610,16 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 	// info, but switch back to single module mode when fetching sums so that we update
 	// the single module's go.sum file.
 	var exitWorkspace func()
-	if r.workspace != nil && r.workspace.hasModule(modload.LoaderState.MainModules.Versions()[0].Path) {
+	if r.workspace != nil && r.workspace.hasModule(loaderstate.MainModules.Versions()[0].Path) {
 		var err error
-		exitWorkspace, err = modload.EnterWorkspace(ctx)
+		exitWorkspace, err = modload.EnterWorkspace(loaderstate, ctx)
 		if err != nil {
 			// A TooNewError can happen for
 			// go get go@newversion when all the required modules
 			// are old enough but the go command itself is not new
 			// enough. See the related comment on the SwitchOrFatal
 			// in runGet when WriteGoMod returns an error.
-			toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
+			toolchain.SwitchOrFatal(loaderstate, ctx, err)
 		}
 	}
 
@@ -1651,7 +1651,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 			AllowErrors:              true,
 			SilenceNoGoErrors:        true,
 		}
-		matches, pkgs := modload.LoadPackages(modload.LoaderState, ctx, pkgOpts, pkgPatterns...)
+		matches, pkgs := modload.LoadPackages(loaderstate, ctx, pkgOpts, pkgPatterns...)
 		for _, m := range matches {
 			if len(m.Errs) > 0 {
 				base.SetExitStatus(1)
@@ -1659,7 +1659,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 			}
 		}
 		for _, pkg := range pkgs {
-			if dir, _, err := modload.Lookup(modload.LoaderState, "", false, pkg); err != nil {
+			if dir, _, err := modload.Lookup(loaderstate, "", false, pkg); err != nil {
 				if dir != "" && errors.Is(err, imports.ErrNoGo) {
 					// Since dir is non-empty, we must have located source files
 					// associated with either the package or its test — ErrNoGo must
@@ -1690,7 +1690,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 		}
 	}
 
-	reqs := modload.LoadModFile(modload.LoaderState, ctx)
+	reqs := modload.LoadModFile(loaderstate, ctx)
 	for m := range relevantMods {
 		if reqs.IsDirect(m.Path) {
 			relevantMods[m] |= direct
@@ -1714,7 +1714,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 	for i := range retractions {
 		i := i
 		r.work.Add(func() {
-			err := modload.CheckRetractions(modload.LoaderState, ctx, retractions[i].m)
+			err := modload.CheckRetractions(loaderstate, ctx, retractions[i].m)
 			if _, ok := errors.AsType[*modload.ModuleRetractedError](err); ok {
 				retractions[i].message = err.Error()
 			}
@@ -1735,7 +1735,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 	for i := range deprecations {
 		i := i
 		r.work.Add(func() {
-			deprecation, err := modload.CheckDeprecation(modload.LoaderState, ctx, deprecations[i].m)
+			deprecation, err := modload.CheckDeprecation(loaderstate, ctx, deprecations[i].m)
 			if err != nil || deprecation == "" {
 				return
 			}
@@ -1765,7 +1765,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 		i := i
 		m := r.buildList[i]
 		mActual := m
-		if mRepl := modload.Replacement(modload.LoaderState, m); mRepl.Path != "" {
+		if mRepl := modload.Replacement(loaderstate, m); mRepl.Path != "" {
 			mActual = mRepl
 		}
 		old := module.Version{Path: m.Path, Version: r.initialVersion[m.Path]}
@@ -1773,7 +1773,7 @@ func (r *resolver) checkPackageProblems(ctx context.Context, pkgPatterns []strin
 			continue
 		}
 		oldActual := old
-		if oldRepl := modload.Replacement(modload.LoaderState, old); oldRepl.Path != "" {
+		if oldRepl := modload.Replacement(loaderstate, old); oldRepl.Path != "" {
 			oldActual = oldRepl
 		}
 		if mActual == oldActual || mActual.Version == "" || !modfetch.HaveSum(oldActual) {
@@ -1944,12 +1944,12 @@ func (r *resolver) reportChanges(oldReqs, newReqs []module.Version) {
 // resolve records that module m must be at its indicated version (which may be
 // "none") due to query q. If some other query forces module m to be at a
 // different version, resolve reports a conflict error.
-func (r *resolver) resolve(q *query, m module.Version) {
+func (r *resolver) resolve(loaderstate *modload.State, q *query, m module.Version) {
 	if m.Path == "" {
 		panic("internal error: resolving a module.Version with an empty path")
 	}
 
-	if modload.LoaderState.MainModules.Contains(m.Path) && m.Version != "" {
+	if loaderstate.MainModules.Contains(m.Path) && m.Version != "" {
 		reportError(q, &modload.QueryMatchesMainModulesError{
 			MainModules: []module.Version{{Path: m.Path}},
 			Pattern:     q.pattern,
@@ -1976,20 +1976,20 @@ func (r *resolver) resolve(q *query, m module.Version) {
 //
 // If the resulting build list is the same as the one resulting from the last
 // call to updateBuildList, updateBuildList returns with changed=false.
-func (r *resolver) updateBuildList(ctx context.Context, additions []module.Version) (changed bool) {
+func (r *resolver) updateBuildList(loaderstate *modload.State, ctx context.Context, additions []module.Version) (changed bool) {
 	defer base.ExitIfErrors()
 
 	resolved := make([]module.Version, 0, len(r.resolvedVersion))
 	for mPath, rv := range r.resolvedVersion {
-		if !modload.LoaderState.MainModules.Contains(mPath) {
+		if !loaderstate.MainModules.Contains(mPath) {
 			resolved = append(resolved, module.Version{Path: mPath, Version: rv.version})
 		}
 	}
 
-	changed, err := modload.EditBuildList(modload.LoaderState, ctx, additions, resolved)
+	changed, err := modload.EditBuildList(loaderstate, ctx, additions, resolved)
 	if err != nil {
 		if errors.Is(err, gover.ErrTooNew) {
-			toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
+			toolchain.SwitchOrFatal(loaderstate, ctx, err)
 		}
 
 		constraint, ok := errors.AsType[*modload.ConstraintError](err)
@@ -2033,9 +2033,9 @@ func (r *resolver) updateBuildList(ctx context.Context, additions []module.Versi
 		return false
 	}
 
-	mg, err := modload.LoadModGraph(modload.LoaderState, ctx, "")
+	mg, err := modload.LoadModGraph(loaderstate, ctx, "")
 	if err != nil {
-		toolchain.SwitchOrFatal(modload.LoaderState, ctx, err)
+		toolchain.SwitchOrFatal(loaderstate, ctx, err)
 	}
 
 	r.buildList = mg.BuildList()
diff --git a/src/cmd/go/internal/modget/query.go b/src/cmd/go/internal/modget/query.go
index 7076bbadce898b..d056c65cadf305 100644
--- a/src/cmd/go/internal/modget/query.go
+++ b/src/cmd/go/internal/modget/query.go
@@ -139,7 +139,7 @@ func errSet(err error) pathSet { return pathSet{err: err} }
 
 // newQuery returns a new query parsed from the raw argument,
 // which must be either path or path@version.
-func newQuery(raw string) (*query, error) {
+func newQuery(loaderstate *modload.State, raw string) (*query, error) {
 	pattern, rawVers, found := strings.Cut(raw, "@")
 	if found && (strings.Contains(rawVers, "@") || rawVers == "") {
 		return nil, fmt.Errorf("invalid module version syntax %q", raw)
@@ -167,14 +167,14 @@ func newQuery(raw string) (*query, error) {
 		q.matchWildcard = pkgpattern.MatchPattern(q.pattern)
 		q.canMatchWildcardInModule = pkgpattern.TreeCanMatchPattern(q.pattern)
 	}
-	if err := q.validate(); err != nil {
+	if err := q.validate(loaderstate); err != nil {
 		return q, err
 	}
 	return q, nil
 }
 
 // validate reports a non-nil error if q is not sensible and well-formed.
-func (q *query) validate() error {
+func (q *query) validate(loaderstate *modload.State) error {
 	if q.patternIsLocal {
 		if q.rawVersion != "" {
 			return fmt.Errorf("can't request explicit version %q of path %q in main module", q.rawVersion, q.pattern)
@@ -184,7 +184,7 @@ func (q *query) validate() error {
 
 	if q.pattern == "all" {
 		// If there is no main module, "all" is not meaningful.
-		if !modload.HasModRoot(modload.LoaderState) {
+		if !modload.HasModRoot(loaderstate) {
 			return fmt.Errorf(`cannot match "all": %v`, modload.ErrNoModRoot)
 		}
 		if !versionOkForMainModule(q.version) {
@@ -192,7 +192,7 @@ func (q *query) validate() error {
 			// request that we remove all module requirements, leaving only the main
 			// module and standard library. Perhaps we should implement that someday.
 			return &modload.QueryUpgradesAllError{
-				MainModules: modload.LoaderState.MainModules.Versions(),
+				MainModules: loaderstate.MainModules.Versions(),
 				Query:       q.version,
 			}
 		}
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index eeb6288f61a12e..ba88713b36edd0 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -71,29 +71,29 @@ func EnterModule(ctx context.Context, enterModroot string) {
 // module to that module in the workspace. There should be no calls to any of the exported
 // functions of the modload package running concurrently with a call to EnterWorkspace as
 // EnterWorkspace will modify the global state they depend on in a non-thread-safe way.
-func EnterWorkspace(ctx context.Context) (exit func(), err error) {
+func EnterWorkspace(loaderstate *State, ctx context.Context) (exit func(), err error) {
 	// Find the identity of the main module that will be updated before we reset modload state.
-	mm := LoaderState.MainModules.mustGetSingleMainModule(LoaderState)
+	mm := loaderstate.MainModules.mustGetSingleMainModule(loaderstate)
 	// Get the updated modfile we will use for that module.
-	_, _, updatedmodfile, err := UpdateGoModFromReqs(LoaderState, ctx, WriteOpts{})
+	_, _, updatedmodfile, err := UpdateGoModFromReqs(loaderstate, ctx, WriteOpts{})
 	if err != nil {
 		return nil, err
 	}
 
 	// Reset the state to a clean state.
-	oldstate := LoaderState.setState(State{})
-	LoaderState.ForceUseModules = true
+	oldstate := loaderstate.setState(State{})
+	loaderstate.ForceUseModules = true
 
 	// Load in workspace mode.
-	InitWorkfile(LoaderState)
-	LoadModFile(LoaderState, ctx)
+	InitWorkfile(loaderstate)
+	LoadModFile(loaderstate, ctx)
 
 	// Update the content of the previous main module, and recompute the requirements.
-	*LoaderState.MainModules.ModFile(mm) = *updatedmodfile
-	LoaderState.requirements = requirementsFromModFiles(LoaderState, ctx, LoaderState.MainModules.workFile, slices.Collect(maps.Values(LoaderState.MainModules.modFiles)), nil)
+	*loaderstate.MainModules.ModFile(mm) = *updatedmodfile
+	loaderstate.requirements = requirementsFromModFiles(loaderstate, ctx, loaderstate.MainModules.workFile, slices.Collect(maps.Values(loaderstate.MainModules.modFiles)), nil)
 
 	return func() {
-		LoaderState.setState(oldstate)
+		loaderstate.setState(oldstate)
 	}, nil
 }
 
diff --git a/src/cmd/go/internal/modload/search.go b/src/cmd/go/internal/modload/search.go
index 9951e68ee8e6c9..1bb4e3f911e04f 100644
--- a/src/cmd/go/internal/modload/search.go
+++ b/src/cmd/go/internal/modload/search.go
@@ -283,20 +283,20 @@ func walkFromIndex(index *modindex.Module, importPathRoot string, isMatch, treeC
 //
 // If m is the zero module.Version, MatchInModule matches the pattern
 // against the standard library (std and cmd) in GOROOT/src.
-func MatchInModule(ctx context.Context, pattern string, m module.Version, tags map[string]bool) *search.Match {
+func MatchInModule(loaderstate *State, ctx context.Context, pattern string, m module.Version, tags map[string]bool) *search.Match {
 	match := search.NewMatch(pattern)
 	if m == (module.Version{}) {
-		matchPackages(LoaderState, ctx, match, tags, includeStd, nil)
+		matchPackages(loaderstate, ctx, match, tags, includeStd, nil)
 	}
 
-	LoadModFile(LoaderState, ctx) // Sets Target, needed by fetch and matchPackages.
+	LoadModFile(loaderstate, ctx) // Sets Target, needed by fetch and matchPackages.
 
 	if !match.IsLiteral() {
-		matchPackages(LoaderState, ctx, match, tags, omitStd, []module.Version{m})
+		matchPackages(loaderstate, ctx, match, tags, omitStd, []module.Version{m})
 		return match
 	}
 
-	root, isLocal, err := fetch(LoaderState, ctx, m)
+	root, isLocal, err := fetch(loaderstate, ctx, m)
 	if err != nil {
 		match.Errs = []error{err}
 		return match

From d9e6f95450134f55d35f63c8da7605019cfda1c3 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 2 Oct 2025 17:00:18 -0400
Subject: [PATCH 193/229] cmd/go: inject State parameter into `workcmd.runSync`

This command modifies the call tree starting at `workcmd.runSync` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/workcmd
rf 'inject modload.LoaderState runSync'
cd ..
./rf-cleanup.zsh

Change-Id: Ib8a7b332b89762a7463ace53243cae6aa0ffcc2d
Reviewed-on: https://go-review.googlesource.com/c/go/+/709987
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modload/init.go | 12 ++++++------
 src/cmd/go/internal/workcmd/sync.go |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index ba88713b36edd0..12f52381b045e7 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -57,14 +57,14 @@ var (
 )
 
 // EnterModule resets MainModules and requirements to refer to just this one module.
-func EnterModule(ctx context.Context, enterModroot string) {
-	LoaderState.MainModules = nil // reset MainModules
-	LoaderState.requirements = nil
-	LoaderState.workFilePath = "" // Force module mode
+func EnterModule(loaderstate *State, ctx context.Context, enterModroot string) {
+	loaderstate.MainModules = nil // reset MainModules
+	loaderstate.requirements = nil
+	loaderstate.workFilePath = "" // Force module mode
 	modfetch.Reset()
 
-	LoaderState.modRoots = []string{enterModroot}
-	LoadModFile(LoaderState, ctx)
+	loaderstate.modRoots = []string{enterModroot}
+	LoadModFile(loaderstate, ctx)
 }
 
 // EnterWorkspace enters workspace mode from module mode, applying the updated requirements to the main
diff --git a/src/cmd/go/internal/workcmd/sync.go b/src/cmd/go/internal/workcmd/sync.go
index 7f45909de5c377..233d12986da769 100644
--- a/src/cmd/go/internal/workcmd/sync.go
+++ b/src/cmd/go/internal/workcmd/sync.go
@@ -104,7 +104,7 @@ func runSync(ctx context.Context, cmd *base.Command, args []string) {
 
 		// Use EnterModule to reset the global state in modload to be in
 		// single-module mode using the modroot of m.
-		modload.EnterModule(ctx, mms.ModRoot(m))
+		modload.EnterModule(modload.LoaderState, ctx, mms.ModRoot(m))
 
 		// Edit the build list in the same way that 'go get' would if we
 		// requested the relevant module versions explicitly.

From e94a5008f6bb182231ed4985651a8e6eb19a83cc Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Fri, 3 Oct 2025 17:05:08 -0400
Subject: [PATCH 194/229] cmd/go: inject State parameter into `work.runBuild`

This command modifies the call tree starting at `work.runBuild` and
`work.runInstall` to inject a `State` parameter to every function that
is currently using the global `modload.LoaderState` variable.  By
explicilty passing a `State` parameter, we can begin to eliminate the
usage of the global `modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/work
rf 'inject modload.LoaderState runBuild'
cd ..
./rf-cleanup.zsh
 # cd work
 # rf 'inject modload.LoaderState runInstall'
 # cd ..
 # ./rf-cleanup.zsh

Change-Id: I232452d877211d4ac72f42aa193b30dab9649481
Reviewed-on: https://go-review.googlesource.com/c/go/+/709990
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/work/action.go | 4 ++--
 src/cmd/go/internal/work/build.go  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/cmd/go/internal/work/action.go b/src/cmd/go/internal/work/action.go
index 7ef7686942a260..1c6d253be2eead 100644
--- a/src/cmd/go/internal/work/action.go
+++ b/src/cmd/go/internal/work/action.go
@@ -1112,12 +1112,12 @@ func (b *Builder) addInstallHeaderAction(a *Action) {
 
 // buildmodeShared takes the "go build" action a1 into the building of a shared library of a1.Deps.
 // That is, the input a1 represents "go build pkgs" and the result represents "go build -buildmode=shared pkgs".
-func (b *Builder) buildmodeShared(mode, depMode BuildMode, args []string, pkgs []*load.Package, a1 *Action) *Action {
+func (b *Builder) buildmodeShared(loaderstate *modload.State, mode, depMode BuildMode, args []string, pkgs []*load.Package, a1 *Action) *Action {
 	name, err := libname(args, pkgs)
 	if err != nil {
 		base.Fatalf("%v", err)
 	}
-	return b.linkSharedAction(modload.LoaderState, mode, depMode, name, a1)
+	return b.linkSharedAction(loaderstate, mode, depMode, name, a1)
 }
 
 // linkSharedAction takes a grouping action a1 corresponding to a list of built packages
diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index c02273664396ac..496247b9a7a7d4 100644
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -554,7 +554,7 @@ func runBuild(ctx context.Context, cmd *base.Command, args []string) {
 		a.Deps = append(a.Deps, b.AutoAction(modload.LoaderState, ModeBuild, depMode, p))
 	}
 	if cfg.BuildBuildmode == "shared" {
-		a = b.buildmodeShared(ModeBuild, depMode, args, pkgs, a)
+		a = b.buildmodeShared(modload.LoaderState, ModeBuild, depMode, args, pkgs, a)
 	}
 	b.Do(ctx, a)
 }
@@ -819,7 +819,7 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
 		// tools above did not apply, and a is just a simple Action
 		// with a list of Deps, one per package named in pkgs,
 		// the same as in runBuild.
-		a = b.buildmodeShared(ModeInstall, ModeInstall, patterns, pkgs, a)
+		a = b.buildmodeShared(modload.LoaderState, ModeInstall, ModeInstall, patterns, pkgs, a)
 	}
 
 	b.Do(ctx, a)

From d57c3fd743b723d564be5764024241cdefd5aa43 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Wed, 8 Oct 2025 15:05:14 -0400
Subject: [PATCH 195/229] cmd/go: inject State parameter into `work.runInstall`

This command modifies the call tree starting at `work.runInstall` to
inject a `State` parameter to every function that is currently using
the global `modload.LoaderState` variable.  By explicilty passing a
`State` parameter, we can begin to eliminate the usage of the global
`modload.LoaderState`.

This commit is part of the overall effort to eliminate global
modloader state.

[git-generate]
cd src/cmd/go/internal/work
rf 'inject modload.LoaderState runInstall'
cd ..
./rf-cleanup.zsh

Change-Id: I038d2c4870d67835c165852b223eaad3e2496202
Reviewed-on: https://go-review.googlesource.com/c/go/+/710304
Reviewed-by: Michael Matloob 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/work/build.go | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index 496247b9a7a7d4..d5687956b4124f 100644
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -689,7 +689,7 @@ func libname(args []string, pkgs []*load.Package) (string, error) {
 func runInstall(ctx context.Context, cmd *base.Command, args []string) {
 	for _, arg := range args {
 		if strings.Contains(arg, "@") && !build.IsLocalImport(arg) && !filepath.IsAbs(arg) {
-			installOutsideModule(ctx, args)
+			installOutsideModule(modload.LoaderState, ctx, args)
 			return
 		}
 	}
@@ -725,7 +725,7 @@ func runInstall(ctx context.Context, cmd *base.Command, args []string) {
 		load.PrepareForCoverageBuild(modload.LoaderState, pkgs)
 	}
 
-	InstallPackages(ctx, args, pkgs)
+	InstallPackages(modload.LoaderState, ctx, args, pkgs)
 }
 
 // omitTestOnly returns pkgs with test-only packages removed.
@@ -745,7 +745,7 @@ func omitTestOnly(pkgs []*load.Package) []*load.Package {
 	return list
 }
 
-func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Package) {
+func InstallPackages(loaderstate *modload.State, ctx context.Context, patterns []string, pkgs []*load.Package) {
 	ctx, span := trace.StartSpan(ctx, "InstallPackages "+strings.Join(patterns, " "))
 	defer span.Done()
 
@@ -797,7 +797,7 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
 		// If p is a tool, delay the installation until the end of the build.
 		// This avoids installing assemblers/compilers that are being executed
 		// by other steps in the build.
-		a1 := b.AutoAction(modload.LoaderState, ModeInstall, depMode, p)
+		a1 := b.AutoAction(loaderstate, ModeInstall, depMode, p)
 		if load.InstallTargetDir(p) == load.ToTool {
 			a.Deps = append(a.Deps, a1.Deps...)
 			a1.Deps = append(a1.Deps, a)
@@ -819,7 +819,7 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
 		// tools above did not apply, and a is just a simple Action
 		// with a list of Deps, one per package named in pkgs,
 		// the same as in runBuild.
-		a = b.buildmodeShared(modload.LoaderState, ModeInstall, ModeInstall, patterns, pkgs, a)
+		a = b.buildmodeShared(loaderstate, ModeInstall, ModeInstall, patterns, pkgs, a)
 	}
 
 	b.Do(ctx, a)
@@ -858,12 +858,12 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
 // in the current directory or parent directories.
 //
 // See golang.org/issue/40276 for details and rationale.
-func installOutsideModule(ctx context.Context, args []string) {
-	modload.LoaderState.ForceUseModules = true
-	modload.LoaderState.RootMode = modload.NoRoot
-	modload.AllowMissingModuleImports(modload.LoaderState)
-	modload.Init(modload.LoaderState)
-	BuildInit(modload.LoaderState)
+func installOutsideModule(loaderstate *modload.State, ctx context.Context, args []string) {
+	loaderstate.ForceUseModules = true
+	loaderstate.RootMode = modload.NoRoot
+	modload.AllowMissingModuleImports(loaderstate)
+	modload.Init(loaderstate)
+	BuildInit(loaderstate)
 
 	// Load packages. Ignore non-main packages.
 	// Print a warning if an argument contains "..." and matches no main packages.
@@ -872,7 +872,7 @@ func installOutsideModule(ctx context.Context, args []string) {
 	// TODO(golang.org/issue/40276): don't report errors loading non-main packages
 	// matched by a pattern.
 	pkgOpts := load.PackageOpts{MainOnly: true}
-	pkgs, err := load.PackagesAndErrorsOutsideModule(modload.LoaderState, ctx, pkgOpts, args)
+	pkgs, err := load.PackagesAndErrorsOutsideModule(loaderstate, ctx, pkgOpts, args)
 	if err != nil {
 		base.Fatal(err)
 	}
@@ -883,7 +883,7 @@ func installOutsideModule(ctx context.Context, args []string) {
 	}
 
 	// Build and install the packages.
-	InstallPackages(ctx, patterns, pkgs)
+	InstallPackages(loaderstate, ctx, patterns, pkgs)
 }
 
 // ExecCmd is the command to use to run user binaries.

From 7503856d4072a748ac5618c6040f84a2f7ddac59 Mon Sep 17 00:00:00 2001
From: Ian Alexander 
Date: Thu, 2 Oct 2025 14:45:23 -0400
Subject: [PATCH 196/229] cmd/go: inject loaderstate into matcher function

This change alters the matcher function in vendorPkg in order to
retrieve the go version from the current loaderstate.

This commit is part of the overall effort to eliminate global
modloader state.

Change-Id: Iedb12bdfe4ab3c24dbbf161db1f3842014415c59
Reviewed-on: https://go-review.googlesource.com/c/go/+/711117
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Matloob 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/internal/modcmd/vendor.go | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index c7be3899f3886f..f864d466bd3d22 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -268,8 +268,8 @@ func moduleLine(m, r module.Version) string {
 	return b.String()
 }
 
-func vendorPkg(loaderstate *modload.State, vdir, pkg string) {
-	src, realPath, _ := modload.Lookup(loaderstate, "", false, pkg)
+func vendorPkg(s *modload.State, vdir, pkg string) {
+	src, realPath, _ := modload.Lookup(s, "", false, pkg)
 	if src == "" {
 		base.Errorf("internal error: no pkg for %s\n", pkg)
 		return
@@ -288,7 +288,11 @@ func vendorPkg(loaderstate *modload.State, vdir, pkg string) {
 
 	copiedFiles := make(map[string]bool)
 	dst := filepath.Join(vdir, pkg)
-	copyDir(dst, src, matchPotentialSourceFile, copiedFiles)
+	matcher := func(dir string, info fs.DirEntry) bool {
+		goVersion := s.MainModules.GoVersion(s)
+		return matchPotentialSourceFile(dir, info, goVersion)
+	}
+	copyDir(dst, src, matcher, copiedFiles)
 	if m := modload.PackageModule(realPath); m.Path != "" {
 		copyMetadata(m.Path, realPath, dst, src, copiedFiles)
 	}
@@ -315,7 +319,7 @@ func vendorPkg(loaderstate *modload.State, vdir, pkg string) {
 		}
 	}
 	var embedPatterns []string
-	if gover.Compare(loaderstate.MainModules.GoVersion(loaderstate), "1.22") >= 0 {
+	if gover.Compare(s.MainModules.GoVersion(s), "1.22") >= 0 {
 		embedPatterns = bp.EmbedPatterns
 	} else {
 		// Maintain the behavior of https://github.com/golang/go/issues/63473
@@ -426,12 +430,12 @@ func matchMetadata(dir string, info fs.DirEntry) bool {
 }
 
 // matchPotentialSourceFile reports whether info may be relevant to a build operation.
-func matchPotentialSourceFile(dir string, info fs.DirEntry) bool {
+func matchPotentialSourceFile(dir string, info fs.DirEntry, goVersion string) bool {
 	if strings.HasSuffix(info.Name(), "_test.go") {
 		return false
 	}
 	if info.Name() == "go.mod" || info.Name() == "go.sum" {
-		if gv := modload.LoaderState.MainModules.GoVersion(modload.LoaderState); gover.Compare(gv, "1.17") >= 0 {
+		if gover.Compare(goVersion, "1.17") >= 0 {
 			// As of Go 1.17, we strip go.mod and go.sum files from dependency modules.
 			// Otherwise, 'go' commands invoked within the vendor subtree may misidentify
 			// an arbitrary directory within the vendor tree as a module root.

From df33c170919faca6ea849ee23fb0af6971fddc5b Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Mon, 3 Feb 2025 15:22:37 +0000
Subject: [PATCH 197/229] runtime: add _Gdeadextra status

_Gdeadextra is almost the same as _Gdead but for goroutines attached to
extra Ms. The primary difference is that it can be transitioned into a
_Gscan status, unlike _Gdead. (Why not just use _Gdead? For safety,
mostly. There's exactly one case where we're going to want to transition
_Gdead to _Gscan|_Gdead, and it's for extra Ms. It's also a bit weird to
call this state dead when it can still have a syscalling P attached to
it.)

This status is used in a follow-up change that changes entersyscall and
exitsyscall.

Change-Id: I169a4c8617aa3dc329574b829203f56c86b58169
Reviewed-on: https://go-review.googlesource.com/c/go/+/646197
Reviewed-by: Cherry Mui 
Reviewed-by: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
---
 src/runtime/heapdump.go    |  2 +-
 src/runtime/mgcmark.go     |  2 +-
 src/runtime/mprof.go       | 15 ++++++++++++---
 src/runtime/preempt.go     |  2 +-
 src/runtime/proc.go        | 21 +++++++++++----------
 src/runtime/runtime-gdb.py |  8 ++++++--
 src/runtime/runtime2.go    |  5 +++++
 src/runtime/synctest.go    |  6 +++---
 src/runtime/traceback.go   | 12 +++++++++++-
 src/runtime/tracestatus.go |  2 +-
 10 files changed, 52 insertions(+), 23 deletions(-)

diff --git a/src/runtime/heapdump.go b/src/runtime/heapdump.go
index d9474034c27c82..9aaee8f90c9d26 100644
--- a/src/runtime/heapdump.go
+++ b/src/runtime/heapdump.go
@@ -415,7 +415,7 @@ func dumpgs() {
 		default:
 			print("runtime: unexpected G.status ", hex(status), "\n")
 			throw("dumpgs in STW - bad status")
-		case _Gdead:
+		case _Gdead, _Gdeadextra:
 			// ok
 		case _Grunnable,
 			_Gsyscall,
diff --git a/src/runtime/mgcmark.go b/src/runtime/mgcmark.go
index ba3824f00dc9cb..dd76973c623ed8 100644
--- a/src/runtime/mgcmark.go
+++ b/src/runtime/mgcmark.go
@@ -911,7 +911,7 @@ func scanstack(gp *g, gcw *gcWork) int64 {
 	default:
 		print("runtime: gp=", gp, ", goid=", gp.goid, ", gp->atomicstatus=", readgstatus(gp), "\n")
 		throw("mark - bad status")
-	case _Gdead:
+	case _Gdead, _Gdeadextra:
 		return 0
 	case _Grunning:
 		print("runtime: gp=", gp, ", goid=", gp.goid, ", gp->atomicstatus=", readgstatus(gp), "\n")
diff --git a/src/runtime/mprof.go b/src/runtime/mprof.go
index 794f57cee24a7c..19e90fbb337e55 100644
--- a/src/runtime/mprof.go
+++ b/src/runtime/mprof.go
@@ -1454,7 +1454,7 @@ func goroutineProfileWithLabelsConcurrent(p []profilerecord.StackRecord, labels
 		// were collecting the profile. But probably better to return a
 		// truncated profile than to crash the whole process.
 		//
-		// For instance, needm moves a goroutine out of the _Gdead state and so
+		// For instance, needm moves a goroutine out of the _Gdeadextra state and so
 		// might be able to change the goroutine count without interacting with
 		// the scheduler. For code like that, the race windows are small and the
 		// combination of features is uncommon, so it's hard to be (and remain)
@@ -1480,7 +1480,7 @@ func tryRecordGoroutineProfileWB(gp1 *g) {
 // in the current goroutine profile: either that it should not be profiled, or
 // that a snapshot of its call stack and labels are now in the profile.
 func tryRecordGoroutineProfile(gp1 *g, pcbuf []uintptr, yield func()) {
-	if readgstatus(gp1) == _Gdead {
+	if status := readgstatus(gp1); status == _Gdead || status == _Gdeadextra {
 		// Dead goroutines should not appear in the profile. Goroutines that
 		// start while profile collection is active will get goroutineProfiled
 		// set to goroutineProfileSatisfied before transitioning out of _Gdead,
@@ -1570,7 +1570,16 @@ func goroutineProfileWithLabelsSync(p []profilerecord.StackRecord, labels []unsa
 	isOK := func(gp1 *g) bool {
 		// Checking isSystemGoroutine here makes GoroutineProfile
 		// consistent with both NumGoroutine and Stack.
-		return gp1 != gp && readgstatus(gp1) != _Gdead && !isSystemGoroutine(gp1, false)
+		if gp1 == gp {
+			return false
+		}
+		if status := readgstatus(gp1); status == _Gdead || status == _Gdeadextra {
+			return false
+		}
+		if isSystemGoroutine(gp1, false) {
+			return false
+		}
+		return true
 	}
 
 	pcbuf := makeProfStack() // see saveg() for explanation
diff --git a/src/runtime/preempt.go b/src/runtime/preempt.go
index 5367f66213804b..1044a6d7207f69 100644
--- a/src/runtime/preempt.go
+++ b/src/runtime/preempt.go
@@ -134,7 +134,7 @@ func suspendG(gp *g) suspendGState {
 			dumpgstatus(gp)
 			throw("invalid g status")
 
-		case _Gdead:
+		case _Gdead, _Gdeadextra:
 			// Nothing to suspend.
 			//
 			// preemptStop may need to be cleared, but
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index fadd9a59639f87..36949fb2cf0681 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -1223,7 +1223,8 @@ func casfrom_Gscanstatus(gp *g, oldval, newval uint32) {
 		_Gscanrunning,
 		_Gscansyscall,
 		_Gscanleaked,
-		_Gscanpreempted:
+		_Gscanpreempted,
+		_Gscandeadextra:
 		if newval == oldval&^_Gscan {
 			success = gp.atomicstatus.CompareAndSwap(oldval, newval)
 		}
@@ -1244,7 +1245,8 @@ func castogscanstatus(gp *g, oldval, newval uint32) bool {
 		_Grunning,
 		_Gwaiting,
 		_Gleaked,
-		_Gsyscall:
+		_Gsyscall,
+		_Gdeadextra:
 		if newval == oldval|_Gscan {
 			r := gp.atomicstatus.CompareAndSwap(oldval, newval)
 			if r {
@@ -2459,7 +2461,7 @@ func needm(signal bool) {
 	}
 
 	// mp.curg is now a real goroutine.
-	casgstatus(mp.curg, _Gdead, _Gsyscall)
+	casgstatus(mp.curg, _Gdeadextra, _Gsyscall)
 	sched.ngsys.Add(-1)
 	sched.nGsyscallNoP.Add(1)
 
@@ -2515,11 +2517,10 @@ func oneNewExtraM() {
 	gp.syscallpc = gp.sched.pc
 	gp.syscallsp = gp.sched.sp
 	gp.stktopsp = gp.sched.sp
-	// malg returns status as _Gidle. Change to _Gdead before
-	// adding to allg where GC can see it. We use _Gdead to hide
-	// this from tracebacks and stack scans since it isn't a
-	// "real" goroutine until needm grabs it.
-	casgstatus(gp, _Gidle, _Gdead)
+	// malg returns status as _Gidle. Change to _Gdeadextra before
+	// adding to allg where GC can see it. _Gdeadextra hides this
+	// from traceback and stack scans.
+	casgstatus(gp, _Gidle, _Gdeadextra)
 	gp.m = mp
 	mp.curg = gp
 	mp.isextra = true
@@ -2593,8 +2594,8 @@ func dropm() {
 		trace = traceAcquire()
 	}
 
-	// Return mp.curg to dead state.
-	casgstatus(mp.curg, _Gsyscall, _Gdead)
+	// Return mp.curg to _Gdeadextra state.
+	casgstatus(mp.curg, _Gsyscall, _Gdeadextra)
 	mp.curg.preemptStop = false
 	sched.ngsys.Add(1)
 	sched.nGsyscallNoP.Add(-1)
diff --git a/src/runtime/runtime-gdb.py b/src/runtime/runtime-gdb.py
index 345a59605e89b9..9d2446a1ebee3e 100644
--- a/src/runtime/runtime-gdb.py
+++ b/src/runtime/runtime-gdb.py
@@ -46,11 +46,13 @@ def read_runtime_const(varname, default):
 G_DEAD = read_runtime_const("'runtime._Gdead'", 6)
 G_ENQUEUE_UNUSED = read_runtime_const("'runtime._Genqueue_unused'", 7)
 G_COPYSTACK = read_runtime_const("'runtime._Gcopystack'", 8)
+G_DEADEXTRA = read_runtime_const("'runtime._Gdeadextra'", 10)
 G_SCAN = read_runtime_const("'runtime._Gscan'", 0x1000)
 G_SCANRUNNABLE = G_SCAN+G_RUNNABLE
 G_SCANRUNNING = G_SCAN+G_RUNNING
 G_SCANSYSCALL = G_SCAN+G_SYSCALL
 G_SCANWAITING = G_SCAN+G_WAITING
+G_SCANEXTRA = G_SCAN+G_DEADEXTRA
 
 sts = {
     G_IDLE: 'idle',
@@ -62,11 +64,13 @@ def read_runtime_const(varname, default):
     G_DEAD: 'dead',
     G_ENQUEUE_UNUSED: 'enqueue',
     G_COPYSTACK: 'copystack',
+    G_DEADEXTRA: 'extra',
     G_SCAN: 'scan',
     G_SCANRUNNABLE: 'runnable+s',
     G_SCANRUNNING: 'running+s',
     G_SCANSYSCALL: 'syscall+s',
     G_SCANWAITING: 'waiting+s',
+    G_SCANEXTRA: 'extra+s',
 }
 
 
@@ -524,7 +528,7 @@ def invoke(self, _arg, _from_tty):
 		# args = gdb.string_to_argv(arg)
 		vp = gdb.lookup_type('void').pointer()
 		for ptr in SliceValue(gdb.parse_and_eval("'runtime.allgs'")):
-			if ptr['atomicstatus']['value'] == G_DEAD:
+			if ptr['atomicstatus']['value'] in [G_DEAD, G_DEADEXTRA]:
 				continue
 			s = ' '
 			if ptr['m']:
@@ -549,7 +553,7 @@ def find_goroutine(goid):
 	"""
 	vp = gdb.lookup_type('void').pointer()
 	for ptr in SliceValue(gdb.parse_and_eval("'runtime.allgs'")):
-		if ptr['atomicstatus']['value'] == G_DEAD:
+		if ptr['atomicstatus']['value'] in [G_DEAD, G_DEADEXTRA]:
 			continue
 		if ptr['goid'] == goid:
 			break
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 6016c6fde054fb..eaf24fe908c5e4 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -90,6 +90,10 @@ const (
 	// _Gleaked represents a leaked goroutine caught by the GC.
 	_Gleaked // 10
 
+	// _Gdeadextra is a _Gdead goroutine that's attached to an extra M
+	// used for cgo callbacks.
+	_Gdeadextra // 11
+
 	// _Gscan combined with one of the above states other than
 	// _Grunning indicates that GC is scanning the stack. The
 	// goroutine is not executing user code and the stack is owned
@@ -108,6 +112,7 @@ const (
 	_Gscanwaiting   = _Gscan + _Gwaiting   // 0x1004
 	_Gscanpreempted = _Gscan + _Gpreempted // 0x1009
 	_Gscanleaked    = _Gscan + _Gleaked    // 0x100a
+	_Gscandeadextra = _Gscan + _Gdeadextra // 0x100b
 )
 
 const (
diff --git a/src/runtime/synctest.go b/src/runtime/synctest.go
index 529f69fd9309b9..8fdf437acbbac1 100644
--- a/src/runtime/synctest.go
+++ b/src/runtime/synctest.go
@@ -52,7 +52,7 @@ func (bubble *synctestBubble) changegstatus(gp *g, oldval, newval uint32) {
 	totalDelta := 0
 	wasRunning := true
 	switch oldval {
-	case _Gdead:
+	case _Gdead, _Gdeadextra:
 		wasRunning = false
 		totalDelta++
 	case _Gwaiting:
@@ -62,7 +62,7 @@ func (bubble *synctestBubble) changegstatus(gp *g, oldval, newval uint32) {
 	}
 	isRunning := true
 	switch newval {
-	case _Gdead:
+	case _Gdead, _Gdeadextra:
 		isRunning = false
 		totalDelta--
 		if gp == bubble.main {
@@ -86,7 +86,7 @@ func (bubble *synctestBubble) changegstatus(gp *g, oldval, newval uint32) {
 			bubble.running++
 		} else {
 			bubble.running--
-			if raceenabled && newval != _Gdead {
+			if raceenabled && newval != _Gdead && newval != _Gdeadextra {
 				// Record that this goroutine parking happens before
 				// any subsequent Wait.
 				racereleasemergeg(gp, bubble.raceaddr())
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index 8882c306edb736..de62762ba76906 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -1208,6 +1208,7 @@ var gStatusStrings = [...]string{
 	_Gcopystack: "copystack",
 	_Gleaked:    "leaked",
 	_Gpreempted: "preempted",
+	_Gdeadextra: "waiting for cgo callback",
 }
 
 func goroutineheader(gp *g) {
@@ -1295,7 +1296,16 @@ func tracebacksomeothers(me *g, showf func(*g) bool) {
 	// against concurrent creation of new Gs, but even with allglock we may
 	// miss Gs created after this loop.
 	forEachGRace(func(gp *g) {
-		if gp == me || gp == curgp || readgstatus(gp) == _Gdead || !showf(gp) || (isSystemGoroutine(gp, false) && level < 2) {
+		if gp == me || gp == curgp {
+			return
+		}
+		if status := readgstatus(gp); status == _Gdead || status == _Gdeadextra {
+			return
+		}
+		if !showf(gp) {
+			return
+		}
+		if isSystemGoroutine(gp, false) && level < 2 {
 			return
 		}
 		print("\n")
diff --git a/src/runtime/tracestatus.go b/src/runtime/tracestatus.go
index 8b5eafd170f488..f09bdfd3554811 100644
--- a/src/runtime/tracestatus.go
+++ b/src/runtime/tracestatus.go
@@ -134,7 +134,7 @@ func goStatusToTraceGoStatus(status uint32, wr waitReason) tracev2.GoStatus {
 		if status == _Gwaiting && wr.isWaitingForSuspendG() {
 			tgs = tracev2.GoRunning
 		}
-	case _Gdead:
+	case _Gdead, _Gdeadextra:
 		throw("tried to trace dead goroutine")
 	default:
 		throw("tried to trace goroutine with invalid or unsupported status")

From dc9a3e2a658176fe1884d65d5a0e7516145404eb Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Tue, 30 Sep 2025 23:54:07 +0000
Subject: [PATCH 198/229] runtime: fix generation skew with trace reentrancy

Currently when performing multiple nested traceAcquires, we re-read
trace.gen on subsequent reads. But this is invalid, since a generation
transition may happen in between a traceAcquire and a nested
traceAcquire. The first one will produce a traceLocker with a gen from
the previous generation, and the second will produce a traceLocker from
the next generation. (Note: generations cannot _complete_ advancement
under traceAcquire, but trace.gen can move forward.) The end result is
earlier events, from the nested traceAcquire, will write to a future
generation, and then previous events will write to a past generation.
This can break the trace.

(There are also a lot of comments left over talking about the
non-reentrancy of the tracer; we should look at those again.)

Change-Id: I08ac8cc86d41ab3e6061c5de58d657b6ad0d19d8
Reviewed-on: https://go-review.googlesource.com/c/go/+/708397
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Pratt 
---
 src/runtime/traceruntime.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/runtime/traceruntime.go b/src/runtime/traceruntime.go
index 06e36fd8026d39..7df6f68b706164 100644
--- a/src/runtime/traceruntime.go
+++ b/src/runtime/traceruntime.go
@@ -29,6 +29,7 @@ type mTraceState struct {
 	buf           [2][tracev2.NumExperiments]*traceBuf // Per-M traceBuf for writing. Indexed by trace.gen%2.
 	link          *m                                   // Snapshot of alllink or freelink.
 	reentered     uint32                               // Whether we've reentered tracing from within tracing.
+	entryGen      uintptr                              // The generation value on first entry.
 	oldthrowsplit bool                                 // gp.throwsplit upon calling traceLocker.writer. For debugging.
 }
 
@@ -212,7 +213,7 @@ func traceAcquireEnabled() traceLocker {
 	// that it is.
 	if mp.trace.seqlock.Load()%2 == 1 {
 		mp.trace.reentered++
-		return traceLocker{mp, trace.gen.Load()}
+		return traceLocker{mp, mp.trace.entryGen}
 	}
 
 	// Acquire the trace seqlock. This prevents traceAdvance from moving forward
@@ -240,6 +241,7 @@ func traceAcquireEnabled() traceLocker {
 		releasem(mp)
 		return traceLocker{}
 	}
+	mp.trace.entryGen = gen
 	return traceLocker{mp, gen}
 }
 

From e4251768439bbd0a6fe4c472aa57bb5257f20b56 Mon Sep 17 00:00:00 2001
From: Joel Sing 
Date: Mon, 20 Oct 2025 15:33:50 +1100
Subject: [PATCH 199/229] cmd/asm: fix typo in comment

Change-Id: I1a7933bce70bcae1f93a45c6810da60d269f48f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/713000
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Michael Pratt 
Reviewed-by: Keith Randall 
Auto-Submit: Joel Sing 
---
 src/cmd/asm/main.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cmd/asm/main.go b/src/cmd/asm/main.go
index 2a9ebe9b3e2178..9db1fec8beac3c 100644
--- a/src/cmd/asm/main.go
+++ b/src/cmd/asm/main.go
@@ -58,7 +58,7 @@ func main() {
 		// nothing
 	case "index":
 		// known to compiler; ignore here so people can use
-		// the same list with -gcflags=-spectre=LIST and -asmflags=-spectrre=LIST
+		// the same list with -gcflags=-spectre=LIST and -asmflags=-spectre=LIST
 	case "all", "ret":
 		ctxt.Retpoline = true
 	}

From 7b81a1e1077dfcddc2c80113dff0a2c3cbde35ae Mon Sep 17 00:00:00 2001
From: Julien Cretel 
Date: Sat, 18 Oct 2025 19:33:12 +0000
Subject: [PATCH 200/229] net/url: reduce allocs in Encode
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This change adds benchmarks for Encode and reverts what CL 617356 did in
this package. At the moment, using maps.Keys in conjunction with
slices.Sorted indeed causes a bunch of closures to escape to heap.
Moreover, all other things being equal, pre-sizing the slice in which
we collect the keys is beneficial to performance when they are "many" (>8)
keys because it results in fewer allocations than if we don't pre-size the
slice.

Here are some benchmark results:

goos: darwin
goarch: amd64
pkg: net/url
cpu: Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz
                                                           │     old      │                 new                 │
                                                           │    sec/op    │   sec/op     vs base                │
EncodeQuery/#00-8                                             2.051n ± 1%   2.343n ± 1%  +14.24% (p=0.000 n=20)
EncodeQuery/#01-8                                             2.337n ± 1%   2.458n ± 4%   +5.16% (p=0.000 n=20)
EncodeQuery/oe=utf8&q=puppies-8                               489.6n ± 0%   284.5n ± 0%  -41.88% (p=0.000 n=20)
EncodeQuery/q=dogs&q=%26&q=7-8                                397.2n ± 1%   231.7n ± 1%  -41.66% (p=0.000 n=20)
EncodeQuery/a=a1&a=a2&a=a3&b=b1&b=b2&b=b3&c=c1&c=c2&c=c3-8    743.1n ± 0%   519.0n ± 0%  -30.16% (p=0.000 n=20)
EncodeQuery/a=a&b=b&c=c&d=d&e=e&f=f&g=g&h=h&i=i-8            1324.0n ± 0%   931.0n ± 0%  -29.68% (p=0.000 n=20)
geomean                                                       98.57n        75.38n       -23.53%

                                                           │      old      │                 new                  │
                                                           │     B/op      │    B/op     vs base                  │
EncodeQuery/#00-8                                             0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=20) ¹
EncodeQuery/#01-8                                             0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=20) ¹
EncodeQuery/oe=utf8&q=puppies-8                              168.00 ± 0%     56.00 ± 0%  -66.67% (p=0.000 n=20)
EncodeQuery/q=dogs&q=%26&q=7-8                               112.00 ± 0%     32.00 ± 0%  -71.43% (p=0.000 n=20)
EncodeQuery/a=a1&a=a2&a=a3&b=b1&b=b2&b=b3&c=c1&c=c2&c=c3-8    296.0 ± 0%     168.0 ± 0%  -43.24% (p=0.000 n=20)
EncodeQuery/a=a&b=b&c=c&d=d&e=e&f=f&g=g&h=h&i=i-8             680.0 ± 0%     264.0 ± 0%  -61.18% (p=0.000 n=20)
geomean                                                                  ²               -47.48%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

                                                           │      old      │                 new                  │
                                                           │   allocs/op   │ allocs/op   vs base                  │
EncodeQuery/#00-8                                             0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=20) ¹
EncodeQuery/#01-8                                             0.000 ± 0%     0.000 ± 0%        ~ (p=1.000 n=20) ¹
EncodeQuery/oe=utf8&q=puppies-8                               8.000 ± 0%     3.000 ± 0%  -62.50% (p=0.000 n=20)
EncodeQuery/q=dogs&q=%26&q=7-8                                7.000 ± 0%     3.000 ± 0%  -57.14% (p=0.000 n=20)
EncodeQuery/a=a1&a=a2&a=a3&b=b1&b=b2&b=b3&c=c1&c=c2&c=c3-8   10.000 ± 0%     5.000 ± 0%  -50.00% (p=0.000 n=20)
EncodeQuery/a=a&b=b&c=c&d=d&e=e&f=f&g=g&h=h&i=i-8            12.000 ± 0%     5.000 ± 0%  -58.33% (p=0.000 n=20)
geomean                                                                  ²               -43.23%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

Change-Id: Ia0d7579f90434f0546d93b680ab18b47a1ffbdac
GitHub-Last-Rev: f25be71e070c2c2f3a2587eea872ca52f3533c40
GitHub-Pull-Request: golang/go#75874
Reviewed-on: https://go-review.googlesource.com/c/go/+/711280
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Florian Lehner 
Reviewed-by: Emmanuel Odeke 
Reviewed-by: Keith Randall 
Reviewed-by: Cherry Mui 
Reviewed-by: Sean Liao 
Reviewed-by: t hepudds 
---
 src/net/url/url.go      | 12 ++++++++++--
 src/net/url/url_test.go | 22 ++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/src/net/url/url.go b/src/net/url/url.go
index 6afa30f162bd25..4508f266084036 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -15,7 +15,6 @@ package url
 import (
 	"errors"
 	"fmt"
-	"maps"
 	"net/netip"
 	"path"
 	"slices"
@@ -1046,7 +1045,16 @@ func (v Values) Encode() string {
 		return ""
 	}
 	var buf strings.Builder
-	for _, k := range slices.Sorted(maps.Keys(v)) {
+	// To minimize allocations, we eschew iterators and pre-size the slice in
+	// which we collect v's keys.
+	keys := make([]string, len(v))
+	var i int
+	for k := range v {
+		keys[i] = k
+		i++
+	}
+	slices.Sort(keys)
+	for _, k := range keys {
 		vs := v[k]
 		keyEscaped := QueryEscape(k)
 		for _, v := range vs {
diff --git a/src/net/url/url_test.go b/src/net/url/url_test.go
index 6084facacc0519..501558403ac771 100644
--- a/src/net/url/url_test.go
+++ b/src/net/url/url_test.go
@@ -1108,6 +1108,17 @@ var encodeQueryTests = []EncodeQueryTest{
 		"b": {"b1", "b2", "b3"},
 		"c": {"c1", "c2", "c3"},
 	}, "a=a1&a=a2&a=a3&b=b1&b=b2&b=b3&c=c1&c=c2&c=c3"},
+	{Values{
+		"a": {"a"},
+		"b": {"b"},
+		"c": {"c"},
+		"d": {"d"},
+		"e": {"e"},
+		"f": {"f"},
+		"g": {"g"},
+		"h": {"h"},
+		"i": {"i"},
+	}, "a=a&b=b&c=c&d=d&e=e&f=f&g=g&h=h&i=i"},
 }
 
 func TestEncodeQuery(t *testing.T) {
@@ -1118,6 +1129,17 @@ func TestEncodeQuery(t *testing.T) {
 	}
 }
 
+func BenchmarkEncodeQuery(b *testing.B) {
+	for _, tt := range encodeQueryTests {
+		b.Run(tt.expected, func(b *testing.B) {
+			b.ReportAllocs()
+			for b.Loop() {
+				tt.m.Encode()
+			}
+		})
+	}
+}
+
 var resolvePathTests = []struct {
 	base, ref, expected string
 }{

From ee4d2c312de90296a6b6f687f6a7ea8b9916af54 Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Thu, 9 Oct 2025 20:30:18 +0000
Subject: [PATCH 201/229] runtime/trace: dump test traces on validation failure

We currently dump traces for internal/trace tests on validation failure,
but not for the runtime/trace package.

This change moves some of the machinery to do this into the testtrace
package and then uses it from the runtime/trace package.

For #75665.

Change-Id: Ibe2d4f3945c1fd21dcbccf56820865f8d2ea41f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/710755
Reviewed-by: Michael Pratt 
Auto-Submit: Michael Knyszek 
LUCI-TryBot-Result: Go LUCI 
---
 src/go/build/deps_test.go                |  2 +-
 src/internal/trace/reader_test.go        | 51 --------------
 src/internal/trace/testtrace/helpers.go  | 87 ++++++++++++++++++++++++
 src/internal/trace/trace_test.go         | 26 ++-----
 src/runtime/trace/flightrecorder_test.go | 11 +--
 src/runtime/trace/trace_test.go          | 17 ++---
 6 files changed, 107 insertions(+), 87 deletions(-)
 create mode 100644 src/internal/trace/testtrace/helpers.go

diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index 8966254d0d9110..8b14e6cb054c11 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -803,7 +803,7 @@ var depsRules = `
 	FMT, testing
 	< internal/cgrouptest;
 
-	regexp, internal/trace, internal/trace/raw, internal/txtar, testing
+	regexp, internal/testenv, internal/trace, internal/trace/raw, internal/txtar, testing
 	< internal/trace/testtrace;
 
 	C, CGO
diff --git a/src/internal/trace/reader_test.go b/src/internal/trace/reader_test.go
index e0733b827dfd19..c03d0676a07c7a 100644
--- a/src/internal/trace/reader_test.go
+++ b/src/internal/trace/reader_test.go
@@ -7,19 +7,14 @@ package trace_test
 import (
 	"bytes"
 	"flag"
-	"fmt"
 	"io"
-	"os"
 	"path/filepath"
 	"runtime"
-	"strings"
 	"testing"
 	"time"
 
 	"internal/trace"
-	"internal/trace/raw"
 	"internal/trace/testtrace"
-	"internal/trace/version"
 )
 
 var (
@@ -131,52 +126,6 @@ func testReader(t *testing.T, tr io.Reader, v *testtrace.Validator, exp *testtra
 	}
 }
 
-func dumpTraceToText(t *testing.T, b []byte) string {
-	t.Helper()
-
-	br, err := raw.NewReader(bytes.NewReader(b))
-	if err != nil {
-		t.Fatalf("dumping trace: %v", err)
-	}
-	var sb strings.Builder
-	tw, err := raw.NewTextWriter(&sb, version.Current)
-	if err != nil {
-		t.Fatalf("dumping trace: %v", err)
-	}
-	for {
-		ev, err := br.ReadEvent()
-		if err == io.EOF {
-			break
-		}
-		if err != nil {
-			t.Fatalf("dumping trace: %v", err)
-		}
-		if err := tw.WriteEvent(ev); err != nil {
-			t.Fatalf("dumping trace: %v", err)
-		}
-	}
-	return sb.String()
-}
-
-func dumpTraceToFile(t *testing.T, testName string, stress bool, b []byte) string {
-	t.Helper()
-
-	desc := "default"
-	if stress {
-		desc = "stress"
-	}
-	name := fmt.Sprintf("%s.%s.trace.", testName, desc)
-	f, err := os.CreateTemp("", name)
-	if err != nil {
-		t.Fatalf("creating temp file: %v", err)
-	}
-	defer f.Close()
-	if _, err := io.Copy(f, bytes.NewReader(b)); err != nil {
-		t.Fatalf("writing trace dump to %q: %v", f.Name(), err)
-	}
-	return f.Name()
-}
-
 func TestTraceGenSync(t *testing.T) {
 	type sync struct {
 		Time          trace.Time
diff --git a/src/internal/trace/testtrace/helpers.go b/src/internal/trace/testtrace/helpers.go
new file mode 100644
index 00000000000000..50f6825bab5df9
--- /dev/null
+++ b/src/internal/trace/testtrace/helpers.go
@@ -0,0 +1,87 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package testtrace
+
+import (
+	"bytes"
+	"fmt"
+	"internal/testenv"
+	"internal/trace/raw"
+	"internal/trace/version"
+	"io"
+	"os"
+	"strings"
+	"testing"
+)
+
+// MustHaveSyscallEvents skips the current test if the current
+// platform does not support true system call events.
+func Dump(t *testing.T, testName string, traceBytes []byte, forceToFile bool) {
+	onBuilder := testenv.Builder() != ""
+	onOldBuilder := !strings.Contains(testenv.Builder(), "gotip") && !strings.Contains(testenv.Builder(), "go1")
+
+	if onBuilder && !forceToFile {
+		// Dump directly to the test log on the builder, since this
+		// data is critical for debugging and this is the only way
+		// we can currently make sure it's retained.
+		s := dumpTraceToText(t, traceBytes)
+		if onOldBuilder && len(s) > 1<<20+512<<10 {
+			// The old build infrastructure truncates logs at ~2 MiB.
+			// Let's assume we're the only failure and give ourselves
+			// up to 1.5 MiB to dump the trace.
+			//
+			// TODO(mknyszek): Remove this when we've migrated off of
+			// the old infrastructure.
+			t.Logf("text trace too large to dump (%d bytes)", len(s))
+		} else {
+			t.Log(s)
+		}
+	} else {
+		// We asked to dump the trace or failed. Write the trace to a file.
+		t.Logf("wrote trace to file: %s", dumpTraceToFile(t, testName, traceBytes))
+	}
+}
+
+func dumpTraceToText(t *testing.T, b []byte) string {
+	t.Helper()
+
+	br, err := raw.NewReader(bytes.NewReader(b))
+	if err != nil {
+		t.Fatalf("dumping trace: %v", err)
+	}
+	var sb strings.Builder
+	tw, err := raw.NewTextWriter(&sb, version.Current)
+	if err != nil {
+		t.Fatalf("dumping trace: %v", err)
+	}
+	for {
+		ev, err := br.ReadEvent()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("dumping trace: %v", err)
+		}
+		if err := tw.WriteEvent(ev); err != nil {
+			t.Fatalf("dumping trace: %v", err)
+		}
+	}
+	return sb.String()
+}
+
+func dumpTraceToFile(t *testing.T, testName string, b []byte) string {
+	t.Helper()
+
+	name := fmt.Sprintf("%s.trace.", testName)
+	f, err := os.CreateTemp(t.ArtifactDir(), name)
+	if err != nil {
+		t.Fatalf("creating temp file: %v", err)
+	}
+	defer f.Close()
+	if _, err := io.Copy(f, bytes.NewReader(b)); err != nil {
+		t.Fatalf("writing trace dump to %q: %v", f.Name(), err)
+	}
+	return f.Name()
+}
diff --git a/src/internal/trace/trace_test.go b/src/internal/trace/trace_test.go
index 4824937b700091..25f671d440cb0c 100644
--- a/src/internal/trace/trace_test.go
+++ b/src/internal/trace/trace_test.go
@@ -668,26 +668,14 @@ func testTraceProg(t *testing.T, progName string, extra func(t *testing.T, trace
 		}
 
 		// Dump some more information on failure.
-		if t.Failed() && onBuilder {
-			// Dump directly to the test log on the builder, since this
-			// data is critical for debugging and this is the only way
-			// we can currently make sure it's retained.
-			t.Log("found bad trace; dumping to test log...")
-			s := dumpTraceToText(t, tb)
-			if onOldBuilder && len(s) > 1<<20+512<<10 {
-				// The old build infrastructure truncates logs at ~2 MiB.
-				// Let's assume we're the only failure and give ourselves
-				// up to 1.5 MiB to dump the trace.
-				//
-				// TODO(mknyszek): Remove this when we've migrated off of
-				// the old infrastructure.
-				t.Logf("text trace too large to dump (%d bytes)", len(s))
-			} else {
-				t.Log(s)
+		if t.Failed() || *dumpTraces {
+			suffix := func(stress bool) string {
+				if stress {
+					return "stress"
+				}
+				return "default"
 			}
-		} else if t.Failed() || *dumpTraces {
-			// We asked to dump the trace or failed. Write the trace to a file.
-			t.Logf("wrote trace to file: %s", dumpTraceToFile(t, testName, stress, tb))
+			testtrace.Dump(t, fmt.Sprintf("%s.%s", testName, suffix(stress)), tb, *dumpTraces)
 		}
 	}
 	t.Run("Default", func(t *testing.T) {
diff --git a/src/runtime/trace/flightrecorder_test.go b/src/runtime/trace/flightrecorder_test.go
index 61cb03dcf60681..221f9c6b673813 100644
--- a/src/runtime/trace/flightrecorder_test.go
+++ b/src/runtime/trace/flightrecorder_test.go
@@ -119,7 +119,7 @@ func TestFlightRecorderConcurrentWriteTo(t *testing.T) {
 		if buf.Len() == 0 {
 			continue
 		}
-		testReader(t, buf, testtrace.ExpectSuccess())
+		testReader(t, buf.Bytes(), testtrace.ExpectSuccess())
 	}
 }
 
@@ -260,12 +260,12 @@ func testFlightRecorder(t *testing.T, fr *trace.FlightRecorder, f flightRecorder
 	traceBytes := buf.Bytes()
 
 	// Parse the trace to make sure it's not broken.
-	testReader(t, bytes.NewReader(traceBytes), testtrace.ExpectSuccess())
+	testReader(t, traceBytes, testtrace.ExpectSuccess())
 	return traceBytes
 }
 
-func testReader(t *testing.T, tr io.Reader, exp *testtrace.Expectation) {
-	r, err := inttrace.NewReader(tr)
+func testReader(t *testing.T, tb []byte, exp *testtrace.Expectation) {
+	r, err := inttrace.NewReader(bytes.NewReader(tb))
 	if err != nil {
 		if err := exp.Check(err); err != nil {
 			t.Error(err)
@@ -292,6 +292,9 @@ func testReader(t *testing.T, tr io.Reader, exp *testtrace.Expectation) {
 	if err := exp.Check(nil); err != nil {
 		t.Error(err)
 	}
+	if t.Failed() || *dumpTraces {
+		testtrace.Dump(t, "trace", tb, *dumpTraces)
+	}
 }
 
 func TestTraceAndFlightRecorder(t *testing.T) {
diff --git a/src/runtime/trace/trace_test.go b/src/runtime/trace/trace_test.go
index b891c8c8f9ff42..2174be061de9df 100644
--- a/src/runtime/trace/trace_test.go
+++ b/src/runtime/trace/trace_test.go
@@ -7,13 +7,16 @@ package trace_test
 import (
 	"bytes"
 	"flag"
-	"os"
 	. "runtime/trace"
 	"testing"
 	"time"
 )
 
-var saveTraces = flag.Bool("savetraces", false, "save traces collected by tests")
+var dumpTraces = flag.Bool("dump-traces", false, "dump traces to a file, even on success")
+
+// This file just contains smoke tests and tests of runtime/trace logic only.
+// It doesn't validate the resulting traces. See the internal/trace package for
+// more comprehensive end-to-end tests.
 
 func TestTraceStartStop(t *testing.T) {
 	if IsEnabled() {
@@ -32,7 +35,6 @@ func TestTraceStartStop(t *testing.T) {
 	if size != buf.Len() {
 		t.Fatalf("trace writes after stop: %v -> %v", size, buf.Len())
 	}
-	saveTrace(t, buf, "TestTraceStartStop")
 }
 
 func TestTraceDoubleStart(t *testing.T) {
@@ -50,12 +52,3 @@ func TestTraceDoubleStart(t *testing.T) {
 	Stop()
 	Stop()
 }
-
-func saveTrace(t *testing.T, buf *bytes.Buffer, name string) {
-	if !*saveTraces {
-		return
-	}
-	if err := os.WriteFile(name+".trace", buf.Bytes(), 0600); err != nil {
-		t.Errorf("failed to write trace file: %s", err)
-	}
-}

From f838faffe21afd2d5c177c04df8836c93e273b4b Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Fri, 17 Oct 2025 19:53:36 +0000
Subject: [PATCH 202/229] runtime: wrap procyield assembly and check for 0

procyield will currently loop infinitely if passed 0 on several
platforms. This change sidesteps this bug by renaming procyield to
procyieldAsm, and adding a wrapper named procyield that checks for
cycles == 0. The benefit of this structure is that procyield called
with a constant cycle count of 0 will be inlined and constant folded
away, the expected behavior of a procyield of 0 cycles.

A follow-up change will fix the assembly to not have this footgun
anymore.

Change-Id: I7068abfeb961bc0fa475e216836f7c0e46b38373
Reviewed-on: https://go-review.googlesource.com/c/go/+/712663
Reviewed-by: Michael Pratt 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Cherry Mui 
Auto-Submit: Michael Knyszek 
---
 src/runtime/asm_386.s     |  2 +-
 src/runtime/asm_amd64.s   |  2 +-
 src/runtime/asm_arm.s     |  2 +-
 src/runtime/asm_arm64.s   |  2 +-
 src/runtime/asm_loong64.s |  2 +-
 src/runtime/asm_mips64x.s |  2 +-
 src/runtime/asm_mipsx.s   |  2 +-
 src/runtime/asm_ppc64x.s  |  2 +-
 src/runtime/asm_riscv64.s |  4 ++--
 src/runtime/asm_s390x.s   |  2 +-
 src/runtime/asm_wasm.s    |  2 +-
 src/runtime/stubs.go      | 18 +++++++++++++++++-
 12 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index df32e90fda8416..a54ca110e53767 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -597,7 +597,7 @@ CALLFN(·call268435456, 268435456)
 CALLFN(·call536870912, 536870912)
 CALLFN(·call1073741824, 1073741824)
 
-TEXT runtime·procyield(SB),NOSPLIT,$0-0
+TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	MOVL	cycles+0(FP), AX
 again:
 	PAUSE
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index 525df96f0028f6..dbf54487a7f502 100644
--- a/src/runtime/asm_amd64.s
+++ b/src/runtime/asm_amd64.s
@@ -815,7 +815,7 @@ CALLFN(·call268435456, 268435456)
 CALLFN(·call536870912, 536870912)
 CALLFN(·call1073741824, 1073741824)
 
-TEXT runtime·procyield(SB),NOSPLIT,$0-0
+TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	MOVL	cycles+0(FP), AX
 again:
 	PAUSE
diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s
index d371e80d8484ac..9373846c74a742 100644
--- a/src/runtime/asm_arm.s
+++ b/src/runtime/asm_arm.s
@@ -839,7 +839,7 @@ TEXT runtime·memhash32(SB),NOSPLIT|NOFRAME,$0-12
 TEXT runtime·memhash64(SB),NOSPLIT|NOFRAME,$0-12
 	JMP	runtime·memhash64Fallback(SB)
 
-TEXT runtime·procyield(SB),NOSPLIT|NOFRAME,$0
+TEXT runtime·procyieldAsm(SB),NOSPLIT|NOFRAME,$0
 	MOVW	cycles+0(FP), R1
 	MOVW	$0, R0
 yieldloop:
diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index a0e82ec830f74b..94a5b9ee6c8665 100644
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -1036,7 +1036,7 @@ aesloop:
 	VMOV	V0.D[0], R0
 	RET
 
-TEXT runtime·procyield(SB),NOSPLIT,$0-0
+TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	MOVWU	cycles+0(FP), R0
 again:
 	YIELD
diff --git a/src/runtime/asm_loong64.s b/src/runtime/asm_loong64.s
index 586bf89a5d3729..a6a5519afb6f7d 100644
--- a/src/runtime/asm_loong64.s
+++ b/src/runtime/asm_loong64.s
@@ -505,7 +505,7 @@ CALLFN(·call268435456, 268435456)
 CALLFN(·call536870912, 536870912)
 CALLFN(·call1073741824, 1073741824)
 
-TEXT runtime·procyield(SB),NOSPLIT,$0-0
+TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	RET
 
 // Save state of caller into g->sched.
diff --git a/src/runtime/asm_mips64x.s b/src/runtime/asm_mips64x.s
index d4523b4a74c47c..532eca752ffc8a 100644
--- a/src/runtime/asm_mips64x.s
+++ b/src/runtime/asm_mips64x.s
@@ -408,7 +408,7 @@ CALLFN(·call268435456, 268435456)
 CALLFN(·call536870912, 536870912)
 CALLFN(·call1073741824, 1073741824)
 
-TEXT runtime·procyield(SB),NOSPLIT,$0-0
+TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	RET
 
 // Save state of caller into g->sched,
diff --git a/src/runtime/asm_mipsx.s b/src/runtime/asm_mipsx.s
index ec352f58289072..2dc3f1c3ad729a 100644
--- a/src/runtime/asm_mipsx.s
+++ b/src/runtime/asm_mipsx.s
@@ -406,7 +406,7 @@ CALLFN(·call268435456, 268435456)
 CALLFN(·call536870912, 536870912)
 CALLFN(·call1073741824, 1073741824)
 
-TEXT runtime·procyield(SB),NOSPLIT,$0-4
+TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-4
 	RET
 
 // Save state of caller into g->sched,
diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index 127010ef971398..e461764e55d213 100644
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -612,7 +612,7 @@ CALLFN(·call268435456, 268435456)
 CALLFN(·call536870912, 536870912)
 CALLFN(·call1073741824, 1073741824)
 
-TEXT runtime·procyield(SB),NOSPLIT|NOFRAME,$0-4
+TEXT runtime·procyieldAsm(SB),NOSPLIT|NOFRAME,$0-4
 	MOVW	cycles+0(FP), R7
 	// POWER does not have a pause/yield instruction equivalent.
 	// Instead, we can lower the program priority by setting the
diff --git a/src/runtime/asm_riscv64.s b/src/runtime/asm_riscv64.s
index efe6047419e8b3..5bd16181ee2b87 100644
--- a/src/runtime/asm_riscv64.s
+++ b/src/runtime/asm_riscv64.s
@@ -367,8 +367,8 @@ TEXT gogo<>(SB), NOSPLIT|NOFRAME, $0
 	MOV	gobuf_pc(T0), T0
 	JALR	ZERO, T0
 
-// func procyield(cycles uint32)
-TEXT runtime·procyield(SB),NOSPLIT,$0-0
+// func procyieldAsm(cycles uint32)
+TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	RET
 
 // Switch to m->g0's stack, call fn(g).
diff --git a/src/runtime/asm_s390x.s b/src/runtime/asm_s390x.s
index 4cc1c0eb104886..bb29845f5839c0 100644
--- a/src/runtime/asm_s390x.s
+++ b/src/runtime/asm_s390x.s
@@ -506,7 +506,7 @@ CALLFN(·call1073741824, 1073741824)
 TEXT callfnMVC<>(SB),NOSPLIT|NOFRAME,$0-0
 	MVC	$1, 0(R4), 0(R6)
 
-TEXT runtime·procyield(SB),NOSPLIT,$0-0
+TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	RET
 
 // Save state of caller into g->sched,
diff --git a/src/runtime/asm_wasm.s b/src/runtime/asm_wasm.s
index 85aa52e0f793c3..c46cb4ae46413c 100644
--- a/src/runtime/asm_wasm.s
+++ b/src/runtime/asm_wasm.s
@@ -200,7 +200,7 @@ TEXT runtime·asminit(SB), NOSPLIT, $0-0
 TEXT ·publicationBarrier(SB), NOSPLIT, $0-0
 	RET
 
-TEXT runtime·procyield(SB), NOSPLIT, $0-0 // FIXME
+TEXT runtime·procyieldAsm(SB), NOSPLIT, $0-0 // FIXME
 	RET
 
 TEXT runtime·breakpoint(SB), NOSPLIT, $0-0
diff --git a/src/runtime/stubs.go b/src/runtime/stubs.go
index 20fc1c59ad933b..1692283541372e 100644
--- a/src/runtime/stubs.go
+++ b/src/runtime/stubs.go
@@ -274,7 +274,23 @@ func reflectcall(stackArgsType *_type, fn, stackArgs unsafe.Pointer, stackArgsSi
 // See go.dev/issue/67401.
 //
 //go:linkname procyield
-func procyield(cycles uint32)
+//go:nosplit
+func procyield(cycles uint32) {
+	if cycles == 0 {
+		return
+	}
+	procyieldAsm(cycles)
+}
+
+// procyieldAsm is the assembly implementation of procyield.
+//
+// It may loop infinitely if called with cycles == 0. Prefer
+// procyield, which will compile down to nothing in such cases,
+// instead.
+//
+// FIXME: The implementation really should not loop infinitely if
+// the number of cycles is 0.
+func procyieldAsm(cycles uint32)
 
 type neverCallThisFunction struct{}
 

From 79ae97fe9bf44814f7bed7e6a6297150070817f3 Mon Sep 17 00:00:00 2001
From: Michael Anthony Knyszek 
Date: Fri, 17 Oct 2025 20:02:55 +0000
Subject: [PATCH 203/229] runtime: make procyieldAsm no longer loop infinitely
 if passed 0

Change-Id: I9f01692373623687e09bee54efebaac0ee361f81
Reviewed-on: https://go-review.googlesource.com/c/go/+/712664
Auto-Submit: Michael Knyszek 
Reviewed-by: Cherry Mui 
LUCI-TryBot-Result: Go LUCI 
---
 src/runtime/asm_386.s    | 3 +++
 src/runtime/asm_amd64.s  | 3 +++
 src/runtime/asm_arm64.s  | 2 ++
 src/runtime/asm_ppc64x.s | 3 +++
 src/runtime/stubs.go     | 7 -------
 5 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index a54ca110e53767..03f1a46b55913f 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -599,10 +599,13 @@ CALLFN(·call1073741824, 1073741824)
 
 TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	MOVL	cycles+0(FP), AX
+	TESTL	AX, AX
+	JZ	done
 again:
 	PAUSE
 	SUBL	$1, AX
 	JNZ	again
+done:
 	RET
 
 TEXT ·publicationBarrier(SB),NOSPLIT,$0-0
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index dbf54487a7f502..a4c6c53a900ce0 100644
--- a/src/runtime/asm_amd64.s
+++ b/src/runtime/asm_amd64.s
@@ -817,10 +817,13 @@ CALLFN(·call1073741824, 1073741824)
 
 TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	MOVL	cycles+0(FP), AX
+	TESTL	AX, AX
+	JZ	done
 again:
 	PAUSE
 	SUBL	$1, AX
 	JNZ	again
+done:
 	RET
 
 
diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index 94a5b9ee6c8665..8bbb6b8a8786d8 100644
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -1038,10 +1038,12 @@ aesloop:
 
 TEXT runtime·procyieldAsm(SB),NOSPLIT,$0-0
 	MOVWU	cycles+0(FP), R0
+	CBZ	R0, done
 again:
 	YIELD
 	SUBW	$1, R0
 	CBNZ	R0, again
+done:
 	RET
 
 // Save state of caller into g->sched,
diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index e461764e55d213..aaa2e4346c7a41 100644
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -614,6 +614,8 @@ CALLFN(·call1073741824, 1073741824)
 
 TEXT runtime·procyieldAsm(SB),NOSPLIT|NOFRAME,$0-4
 	MOVW	cycles+0(FP), R7
+	CMP	$0, R7
+	BEQ	done
 	// POWER does not have a pause/yield instruction equivalent.
 	// Instead, we can lower the program priority by setting the
 	// Program Priority Register prior to the wait loop and set it
@@ -625,6 +627,7 @@ again:
 	CMP	$0, R7
 	BNE	again
 	OR	R6, R6, R6	// Set PPR priority back to medium-low
+done:
 	RET
 
 // Save state of caller into g->sched,
diff --git a/src/runtime/stubs.go b/src/runtime/stubs.go
index 1692283541372e..d5a35d15b25141 100644
--- a/src/runtime/stubs.go
+++ b/src/runtime/stubs.go
@@ -283,13 +283,6 @@ func procyield(cycles uint32) {
 }
 
 // procyieldAsm is the assembly implementation of procyield.
-//
-// It may loop infinitely if called with cycles == 0. Prefer
-// procyield, which will compile down to nothing in such cases,
-// instead.
-//
-// FIXME: The implementation really should not loop infinitely if
-// the number of cycles is 0.
 func procyieldAsm(cycles uint32)
 
 type neverCallThisFunction struct{}

From 99cf4d671cb48133d6c23e547eb46e1b9d3f21e4 Mon Sep 17 00:00:00 2001
From: Guoqi Chen 
Date: Thu, 11 Sep 2025 16:21:44 +0800
Subject: [PATCH 204/229] runtime: save lasx and lsx registers in loong64 async
 preemption

This is a port of CL 669195 and CL 695916 adjusted to save loong64
lasx and lsx registers off stack.

Change-Id: Ie56787c76259a9545f5a8adcb09f588c8451bbd6
Reviewed-on: https://go-review.googlesource.com/c/go/+/711180
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Dmitri Shuralyov 
Reviewed-by: Michael Pratt 
Reviewed-by: Meidan Li 
---
 src/runtime/mkpreempt.go       |  79 ++++++++-
 src/runtime/preempt_loong64.go |  38 +++++
 src/runtime/preempt_loong64.s  | 298 +++++++++++++++++++++++++--------
 src/runtime/preempt_noxreg.go  |   2 +-
 src/runtime/preempt_xreg.go    |   2 +-
 5 files changed, 339 insertions(+), 80 deletions(-)
 create mode 100644 src/runtime/preempt_loong64.go

diff --git a/src/runtime/mkpreempt.go b/src/runtime/mkpreempt.go
index 7b84ba0a6fbaaf..dc951cd9a99f99 100644
--- a/src/runtime/mkpreempt.go
+++ b/src/runtime/mkpreempt.go
@@ -713,10 +713,11 @@ func genMIPS(g *gen, _64bit bool) {
 }
 
 func genLoong64(g *gen) {
-	p := g.p
+	const xReg = "R4" // *xRegState
+
+	p, label := g.p, g.label
 
 	mov := "MOVV"
-	movf := "MOVD"
 	add := "ADDV"
 	sub := "SUBV"
 	regsize := 8
@@ -732,12 +733,6 @@ func genLoong64(g *gen) {
 		l.add(mov, reg, regsize)
 	}
 
-	// Add floating point registers F0-F31.
-	for i := 0; i <= 31; i++ {
-		reg := fmt.Sprintf("F%d", i)
-		l.add(movf, reg, regsize)
-	}
-
 	// Add condition flag register fcc0-fcc7
 	sv := ""
 	rs := ""
@@ -764,12 +759,80 @@ func genLoong64(g *gen) {
 		mov+" %d(R3), R5\n"+rs,
 		regsize)
 
+	// Create layouts for lasx, lsx and fp registers.
+	lasxRegs := layout{sp: xReg}
+	lsxRegs := lasxRegs
+	fpRegs := lasxRegs
+	for i := 0; i <= 31; i++ {
+		lasxRegs.add("XVMOVQ", fmt.Sprintf("X%d", i), 256/8)
+		lsxRegs.add("VMOVQ", fmt.Sprintf("V%d", i), 128/8)
+		fpRegs.add("MOVD", fmt.Sprintf("F%d", i), 64/8)
+	}
+
+	for i := range lsxRegs.regs {
+		for j := range lsxRegs.regs[i].regs {
+			lsxRegs.regs[i].regs[j].pos = lasxRegs.regs[i].regs[j].pos
+			fpRegs.regs[i].regs[j].pos = lasxRegs.regs[i].regs[j].pos
+		}
+	}
+	writeXRegs(g.goarch, &lasxRegs)
+
 	// allocate frame, save PC of interrupted instruction (in LR)
 	p(mov+" R1, -%d(R3)", l.stack)
 	p(sub+" $%d, R3", l.stack)
 
+	p("// Save GPs")
 	l.save(g)
+
+	p("// Save extended register state to p.xRegs.scratch")
+	p("MOVV g_m(g), %s", xReg)
+	p("MOVV m_p(%s), %s", xReg, xReg)
+	p("ADDV $(p_xRegs+xRegPerP_scratch), %s, %s", xReg, xReg)
+
+	p("MOVBU internal∕cpu·Loong64+const_offsetLOONG64HasLASX(SB), R5")
+	p("BNE R5, saveLASX")
+
+	p("MOVBU internal∕cpu·Loong64+const_offsetLOONG64HasLSX(SB), R5")
+	p("BNE R5, saveLSX")
+
+	label("saveFP:")
+	fpRegs.save(g)
+	p("JMP preempt")
+
+	label("saveLSX:")
+	lsxRegs.save(g)
+	p("JMP preempt")
+
+	label("saveLASX:")
+	lasxRegs.save(g)
+
+	label("preempt:")
 	p("CALL ·asyncPreempt2(SB)")
+
+	p("// Restore non-GPs from *p.xRegs.cache")
+	p("MOVV g_m(g), %s", xReg)
+	p("MOVV m_p(%s), %s", xReg, xReg)
+	p("MOVV (p_xRegs+xRegPerP_cache)(%s), %s", xReg, xReg)
+
+	p("MOVBU internal∕cpu·Loong64+const_offsetLOONG64HasLASX(SB), R5")
+	p("BNE R5, restoreLASX")
+
+	p("MOVBU internal∕cpu·Loong64+const_offsetLOONG64HasLSX(SB), R5")
+	p("BNE R5, restoreLSX")
+
+	label("restoreFP:")
+	fpRegs.restore(g)
+	p("JMP restoreGPs")
+
+	label("restoreLSX:")
+	lsxRegs.restore(g)
+	p("JMP restoreGPs")
+
+	label("restoreLASX:")
+	lasxRegs.restore(g)
+
+	p("// Restore GPs")
+	label("restoreGPs:")
 	l.restore(g)
 
 	p(mov+" %d(R3), R1", l.stack)      // sigctxt.pushCall has pushed LR (at interrupt) on stack, restore it
diff --git a/src/runtime/preempt_loong64.go b/src/runtime/preempt_loong64.go
new file mode 100644
index 00000000000000..c7fec338f26694
--- /dev/null
+++ b/src/runtime/preempt_loong64.go
@@ -0,0 +1,38 @@
+// Code generated by mkpreempt.go; DO NOT EDIT.
+
+package runtime
+
+type xRegs struct {
+	X0  [32]byte
+	X1  [32]byte
+	X2  [32]byte
+	X3  [32]byte
+	X4  [32]byte
+	X5  [32]byte
+	X6  [32]byte
+	X7  [32]byte
+	X8  [32]byte
+	X9  [32]byte
+	X10 [32]byte
+	X11 [32]byte
+	X12 [32]byte
+	X13 [32]byte
+	X14 [32]byte
+	X15 [32]byte
+	X16 [32]byte
+	X17 [32]byte
+	X18 [32]byte
+	X19 [32]byte
+	X20 [32]byte
+	X21 [32]byte
+	X22 [32]byte
+	X23 [32]byte
+	X24 [32]byte
+	X25 [32]byte
+	X26 [32]byte
+	X27 [32]byte
+	X28 [32]byte
+	X29 [32]byte
+	X30 [32]byte
+	X31 [32]byte
+}
diff --git a/src/runtime/preempt_loong64.s b/src/runtime/preempt_loong64.s
index 626dc4b6f67aec..4bc7ea3947bd27 100644
--- a/src/runtime/preempt_loong64.s
+++ b/src/runtime/preempt_loong64.s
@@ -4,8 +4,9 @@
 #include "textflag.h"
 
 TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
-	MOVV R1, -480(R3)
-	SUBV $480, R3
+	MOVV R1, -224(R3)
+	SUBV $224, R3
+	// Save GPs
 	MOVV R4, 8(R3)
 	MOVV R5, 16(R3)
 	MOVV R6, 24(R3)
@@ -32,38 +33,6 @@ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
 	MOVV R28, 192(R3)
 	MOVV R29, 200(R3)
 	MOVV R31, 208(R3)
-	MOVD F0, 216(R3)
-	MOVD F1, 224(R3)
-	MOVD F2, 232(R3)
-	MOVD F3, 240(R3)
-	MOVD F4, 248(R3)
-	MOVD F5, 256(R3)
-	MOVD F6, 264(R3)
-	MOVD F7, 272(R3)
-	MOVD F8, 280(R3)
-	MOVD F9, 288(R3)
-	MOVD F10, 296(R3)
-	MOVD F11, 304(R3)
-	MOVD F12, 312(R3)
-	MOVD F13, 320(R3)
-	MOVD F14, 328(R3)
-	MOVD F15, 336(R3)
-	MOVD F16, 344(R3)
-	MOVD F17, 352(R3)
-	MOVD F18, 360(R3)
-	MOVD F19, 368(R3)
-	MOVD F20, 376(R3)
-	MOVD F21, 384(R3)
-	MOVD F22, 392(R3)
-	MOVD F23, 400(R3)
-	MOVD F24, 408(R3)
-	MOVD F25, 416(R3)
-	MOVD F26, 424(R3)
-	MOVD F27, 432(R3)
-	MOVD F28, 440(R3)
-	MOVD F29, 448(R3)
-	MOVD F30, 456(R3)
-	MOVD F31, 464(R3)
 	MOVV FCC0, R4
 	BSTRINSV $7, R4, $0, R5
 	MOVV FCC1, R4
@@ -80,9 +49,230 @@ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
 	BSTRINSV $55, R4, $48, R5
 	MOVV FCC7, R4
 	BSTRINSV $63, R4, $56, R5
-	MOVV R5, 472(R3)
+	MOVV R5, 216(R3)
+	// Save extended register state to p.xRegs.scratch
+	MOVV g_m(g), R4
+	MOVV m_p(R4), R4
+	ADDV $(p_xRegs+xRegPerP_scratch), R4, R4
+	MOVBU internal∕cpu·Loong64+const_offsetLOONG64HasLASX(SB), R5
+	BNE R5, saveLASX
+	MOVBU internal∕cpu·Loong64+const_offsetLOONG64HasLSX(SB), R5
+	BNE R5, saveLSX
+saveFP:
+	MOVD F0, 0(R4)
+	MOVD F1, 32(R4)
+	MOVD F2, 64(R4)
+	MOVD F3, 96(R4)
+	MOVD F4, 128(R4)
+	MOVD F5, 160(R4)
+	MOVD F6, 192(R4)
+	MOVD F7, 224(R4)
+	MOVD F8, 256(R4)
+	MOVD F9, 288(R4)
+	MOVD F10, 320(R4)
+	MOVD F11, 352(R4)
+	MOVD F12, 384(R4)
+	MOVD F13, 416(R4)
+	MOVD F14, 448(R4)
+	MOVD F15, 480(R4)
+	MOVD F16, 512(R4)
+	MOVD F17, 544(R4)
+	MOVD F18, 576(R4)
+	MOVD F19, 608(R4)
+	MOVD F20, 640(R4)
+	MOVD F21, 672(R4)
+	MOVD F22, 704(R4)
+	MOVD F23, 736(R4)
+	MOVD F24, 768(R4)
+	MOVD F25, 800(R4)
+	MOVD F26, 832(R4)
+	MOVD F27, 864(R4)
+	MOVD F28, 896(R4)
+	MOVD F29, 928(R4)
+	MOVD F30, 960(R4)
+	MOVD F31, 992(R4)
+	JMP preempt
+saveLSX:
+	VMOVQ V0, 0(R4)
+	VMOVQ V1, 32(R4)
+	VMOVQ V2, 64(R4)
+	VMOVQ V3, 96(R4)
+	VMOVQ V4, 128(R4)
+	VMOVQ V5, 160(R4)
+	VMOVQ V6, 192(R4)
+	VMOVQ V7, 224(R4)
+	VMOVQ V8, 256(R4)
+	VMOVQ V9, 288(R4)
+	VMOVQ V10, 320(R4)
+	VMOVQ V11, 352(R4)
+	VMOVQ V12, 384(R4)
+	VMOVQ V13, 416(R4)
+	VMOVQ V14, 448(R4)
+	VMOVQ V15, 480(R4)
+	VMOVQ V16, 512(R4)
+	VMOVQ V17, 544(R4)
+	VMOVQ V18, 576(R4)
+	VMOVQ V19, 608(R4)
+	VMOVQ V20, 640(R4)
+	VMOVQ V21, 672(R4)
+	VMOVQ V22, 704(R4)
+	VMOVQ V23, 736(R4)
+	VMOVQ V24, 768(R4)
+	VMOVQ V25, 800(R4)
+	VMOVQ V26, 832(R4)
+	VMOVQ V27, 864(R4)
+	VMOVQ V28, 896(R4)
+	VMOVQ V29, 928(R4)
+	VMOVQ V30, 960(R4)
+	VMOVQ V31, 992(R4)
+	JMP preempt
+saveLASX:
+	XVMOVQ X0, 0(R4)
+	XVMOVQ X1, 32(R4)
+	XVMOVQ X2, 64(R4)
+	XVMOVQ X3, 96(R4)
+	XVMOVQ X4, 128(R4)
+	XVMOVQ X5, 160(R4)
+	XVMOVQ X6, 192(R4)
+	XVMOVQ X7, 224(R4)
+	XVMOVQ X8, 256(R4)
+	XVMOVQ X9, 288(R4)
+	XVMOVQ X10, 320(R4)
+	XVMOVQ X11, 352(R4)
+	XVMOVQ X12, 384(R4)
+	XVMOVQ X13, 416(R4)
+	XVMOVQ X14, 448(R4)
+	XVMOVQ X15, 480(R4)
+	XVMOVQ X16, 512(R4)
+	XVMOVQ X17, 544(R4)
+	XVMOVQ X18, 576(R4)
+	XVMOVQ X19, 608(R4)
+	XVMOVQ X20, 640(R4)
+	XVMOVQ X21, 672(R4)
+	XVMOVQ X22, 704(R4)
+	XVMOVQ X23, 736(R4)
+	XVMOVQ X24, 768(R4)
+	XVMOVQ X25, 800(R4)
+	XVMOVQ X26, 832(R4)
+	XVMOVQ X27, 864(R4)
+	XVMOVQ X28, 896(R4)
+	XVMOVQ X29, 928(R4)
+	XVMOVQ X30, 960(R4)
+	XVMOVQ X31, 992(R4)
+preempt:
 	CALL ·asyncPreempt2(SB)
-	MOVV 472(R3), R5
+	// Restore non-GPs from *p.xRegs.cache
+	MOVV g_m(g), R4
+	MOVV m_p(R4), R4
+	MOVV (p_xRegs+xRegPerP_cache)(R4), R4
+	MOVBU internal∕cpu·Loong64+const_offsetLOONG64HasLASX(SB), R5
+	BNE R5, restoreLASX
+	MOVBU internal∕cpu·Loong64+const_offsetLOONG64HasLSX(SB), R5
+	BNE R5, restoreLSX
+restoreFP:
+	MOVD 992(R4), F31
+	MOVD 960(R4), F30
+	MOVD 928(R4), F29
+	MOVD 896(R4), F28
+	MOVD 864(R4), F27
+	MOVD 832(R4), F26
+	MOVD 800(R4), F25
+	MOVD 768(R4), F24
+	MOVD 736(R4), F23
+	MOVD 704(R4), F22
+	MOVD 672(R4), F21
+	MOVD 640(R4), F20
+	MOVD 608(R4), F19
+	MOVD 576(R4), F18
+	MOVD 544(R4), F17
+	MOVD 512(R4), F16
+	MOVD 480(R4), F15
+	MOVD 448(R4), F14
+	MOVD 416(R4), F13
+	MOVD 384(R4), F12
+	MOVD 352(R4), F11
+	MOVD 320(R4), F10
+	MOVD 288(R4), F9
+	MOVD 256(R4), F8
+	MOVD 224(R4), F7
+	MOVD 192(R4), F6
+	MOVD 160(R4), F5
+	MOVD 128(R4), F4
+	MOVD 96(R4), F3
+	MOVD 64(R4), F2
+	MOVD 32(R4), F1
+	MOVD 0(R4), F0
+	JMP restoreGPs
+restoreLSX:
+	VMOVQ 992(R4), V31
+	VMOVQ 960(R4), V30
+	VMOVQ 928(R4), V29
+	VMOVQ 896(R4), V28
+	VMOVQ 864(R4), V27
+	VMOVQ 832(R4), V26
+	VMOVQ 800(R4), V25
+	VMOVQ 768(R4), V24
+	VMOVQ 736(R4), V23
+	VMOVQ 704(R4), V22
+	VMOVQ 672(R4), V21
+	VMOVQ 640(R4), V20
+	VMOVQ 608(R4), V19
+	VMOVQ 576(R4), V18
+	VMOVQ 544(R4), V17
+	VMOVQ 512(R4), V16
+	VMOVQ 480(R4), V15
+	VMOVQ 448(R4), V14
+	VMOVQ 416(R4), V13
+	VMOVQ 384(R4), V12
+	VMOVQ 352(R4), V11
+	VMOVQ 320(R4), V10
+	VMOVQ 288(R4), V9
+	VMOVQ 256(R4), V8
+	VMOVQ 224(R4), V7
+	VMOVQ 192(R4), V6
+	VMOVQ 160(R4), V5
+	VMOVQ 128(R4), V4
+	VMOVQ 96(R4), V3
+	VMOVQ 64(R4), V2
+	VMOVQ 32(R4), V1
+	VMOVQ 0(R4), V0
+	JMP restoreGPs
+restoreLASX:
+	XVMOVQ 992(R4), X31
+	XVMOVQ 960(R4), X30
+	XVMOVQ 928(R4), X29
+	XVMOVQ 896(R4), X28
+	XVMOVQ 864(R4), X27
+	XVMOVQ 832(R4), X26
+	XVMOVQ 800(R4), X25
+	XVMOVQ 768(R4), X24
+	XVMOVQ 736(R4), X23
+	XVMOVQ 704(R4), X22
+	XVMOVQ 672(R4), X21
+	XVMOVQ 640(R4), X20
+	XVMOVQ 608(R4), X19
+	XVMOVQ 576(R4), X18
+	XVMOVQ 544(R4), X17
+	XVMOVQ 512(R4), X16
+	XVMOVQ 480(R4), X15
+	XVMOVQ 448(R4), X14
+	XVMOVQ 416(R4), X13
+	XVMOVQ 384(R4), X12
+	XVMOVQ 352(R4), X11
+	XVMOVQ 320(R4), X10
+	XVMOVQ 288(R4), X9
+	XVMOVQ 256(R4), X8
+	XVMOVQ 224(R4), X7
+	XVMOVQ 192(R4), X6
+	XVMOVQ 160(R4), X5
+	XVMOVQ 128(R4), X4
+	XVMOVQ 96(R4), X3
+	XVMOVQ 64(R4), X2
+	XVMOVQ 32(R4), X1
+	XVMOVQ 0(R4), X0
+	// Restore GPs
+restoreGPs:
+	MOVV 216(R3), R5
 	BSTRPICKV $7, R5, $0, R4
 	MOVV R4, FCC0
 	BSTRPICKV $15, R5, $8, R4
@@ -99,38 +289,6 @@ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
 	MOVV R4, FCC6
 	BSTRPICKV $63, R5, $56, R4
 	MOVV R4, FCC7
-	MOVD 464(R3), F31
-	MOVD 456(R3), F30
-	MOVD 448(R3), F29
-	MOVD 440(R3), F28
-	MOVD 432(R3), F27
-	MOVD 424(R3), F26
-	MOVD 416(R3), F25
-	MOVD 408(R3), F24
-	MOVD 400(R3), F23
-	MOVD 392(R3), F22
-	MOVD 384(R3), F21
-	MOVD 376(R3), F20
-	MOVD 368(R3), F19
-	MOVD 360(R3), F18
-	MOVD 352(R3), F17
-	MOVD 344(R3), F16
-	MOVD 336(R3), F15
-	MOVD 328(R3), F14
-	MOVD 320(R3), F13
-	MOVD 312(R3), F12
-	MOVD 304(R3), F11
-	MOVD 296(R3), F10
-	MOVD 288(R3), F9
-	MOVD 280(R3), F8
-	MOVD 272(R3), F7
-	MOVD 264(R3), F6
-	MOVD 256(R3), F5
-	MOVD 248(R3), F4
-	MOVD 240(R3), F3
-	MOVD 232(R3), F2
-	MOVD 224(R3), F1
-	MOVD 216(R3), F0
 	MOVV 208(R3), R31
 	MOVV 200(R3), R29
 	MOVV 192(R3), R28
@@ -157,7 +315,7 @@ TEXT ·asyncPreempt(SB),NOSPLIT|NOFRAME,$0-0
 	MOVV 24(R3), R6
 	MOVV 16(R3), R5
 	MOVV 8(R3), R4
-	MOVV 480(R3), R1
+	MOVV 224(R3), R1
 	MOVV (R3), R30
-	ADDV $488, R3
+	ADDV $232, R3
 	JMP (R30)
diff --git a/src/runtime/preempt_noxreg.go b/src/runtime/preempt_noxreg.go
index 9f03b2b333420e..977bf0bcec7b34 100644
--- a/src/runtime/preempt_noxreg.go
+++ b/src/runtime/preempt_noxreg.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !amd64 && !arm64
+//go:build !amd64 && !arm64 && !loong64
 
 // This provides common support for architectures that DO NOT use extended
 // register state in asynchronous preemption.
diff --git a/src/runtime/preempt_xreg.go b/src/runtime/preempt_xreg.go
index f4578a4d76d889..cc52c5f3c4ec2a 100644
--- a/src/runtime/preempt_xreg.go
+++ b/src/runtime/preempt_xreg.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build amd64 || arm64
+//go:build amd64 || arm64 || loong64
 
 // This provides common support for architectures that use extended register
 // state in asynchronous preemption.

From 8539691d0c0c04be291e18972316fa4b6d02bbcf Mon Sep 17 00:00:00 2001
From: Filippo Valsorda 
Date: Wed, 8 Oct 2025 13:15:27 +0200
Subject: [PATCH 205/229] crypto/internal/fips140/entropy: move to
 crypto/internal/entropy/v1.0.0

The lab confirmed the that entropy source doesn't have to be inside the
module boundary, although changing the entropy source of a module does
require recertification.

Move the v1.0.0 entropy source out of crypto/internal/fips140, to a
versioned path that lets us keep multiple versions (which would be used
by different modules) if we wish to.

Change-Id: I6a6a69647e9dfca1c375650a0869bdc001d65173
Reviewed-on: https://go-review.googlesource.com/c/go/+/710057
Reviewed-by: Daniel McCarney 
Auto-Submit: Filippo Valsorda 
Reviewed-by: David Chase 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Dmitri Shuralyov 
---
 src/crypto/internal/entropy/entropy.go                |  6 ++++--
 .../{fips140/entropy => entropy/v1.0.0}/entropy.go    |  0
 .../{fips140/entropy => entropy/v1.0.0}/sha384.go     |  0
 src/crypto/internal/fips140/drbg/rand.go              |  2 +-
 src/crypto/internal/fips140deps/fipsdeps_test.go      | 11 +++++------
 src/crypto/internal/fips140test/entropy_test.go       |  8 ++++----
 src/go/build/deps_test.go                             |  4 ++--
 7 files changed, 16 insertions(+), 15 deletions(-)
 rename src/crypto/internal/{fips140/entropy => entropy/v1.0.0}/entropy.go (100%)
 rename src/crypto/internal/{fips140/entropy => entropy/v1.0.0}/sha384.go (100%)

diff --git a/src/crypto/internal/entropy/entropy.go b/src/crypto/internal/entropy/entropy.go
index 73fd5298007a11..6e16f19de52ae4 100644
--- a/src/crypto/internal/entropy/entropy.go
+++ b/src/crypto/internal/entropy/entropy.go
@@ -4,8 +4,10 @@
 
 // Package entropy provides the passive entropy source for the FIPS 140-3
 // module. It is only used in FIPS mode by [crypto/internal/fips140/drbg.Read]
-// from the FIPS 140-3 Go Cryptographic Module v1.0.0. Later versions of the
-// module have an internal CPU jitter-based entropy source.
+// from the FIPS 140-3 Go Cryptographic Module v1.0.0.
+//
+// Later versions of the module use the CPU jitter-based entropy source in the
+// crypto/internal/entropy/v1.0.0 sub-package.
 //
 // This complied with IG 9.3.A, Additional Comment 12, which until January 1,
 // 2026 allows new modules to meet an [earlier version] of Resolution 2(b):
diff --git a/src/crypto/internal/fips140/entropy/entropy.go b/src/crypto/internal/entropy/v1.0.0/entropy.go
similarity index 100%
rename from src/crypto/internal/fips140/entropy/entropy.go
rename to src/crypto/internal/entropy/v1.0.0/entropy.go
diff --git a/src/crypto/internal/fips140/entropy/sha384.go b/src/crypto/internal/entropy/v1.0.0/sha384.go
similarity index 100%
rename from src/crypto/internal/fips140/entropy/sha384.go
rename to src/crypto/internal/entropy/v1.0.0/sha384.go
diff --git a/src/crypto/internal/fips140/drbg/rand.go b/src/crypto/internal/fips140/drbg/rand.go
index 3ccb018e326047..cec697c7ab89ec 100644
--- a/src/crypto/internal/fips140/drbg/rand.go
+++ b/src/crypto/internal/fips140/drbg/rand.go
@@ -9,8 +9,8 @@
 package drbg
 
 import (
+	entropy "crypto/internal/entropy/v1.0.0"
 	"crypto/internal/fips140"
-	"crypto/internal/fips140/entropy"
 	"crypto/internal/randutil"
 	"crypto/internal/sysrand"
 	"io"
diff --git a/src/crypto/internal/fips140deps/fipsdeps_test.go b/src/crypto/internal/fips140deps/fipsdeps_test.go
index 97552dc1ce10f1..3eaae1830d0e18 100644
--- a/src/crypto/internal/fips140deps/fipsdeps_test.go
+++ b/src/crypto/internal/fips140deps/fipsdeps_test.go
@@ -16,10 +16,11 @@ import (
 //
 // DO NOT add new packages here just to make the tests pass.
 var AllowedInternalPackages = map[string]bool{
-	// entropy.Depleted is the external passive entropy source, and sysrand.Read
+	// entropy.Depleted/Seed is the entropy source, and sysrand.Read
 	// is the actual (but uncredited!) random bytes source.
-	"crypto/internal/entropy": true,
-	"crypto/internal/sysrand": true,
+	"crypto/internal/entropy":        true,
+	"crypto/internal/entropy/v1.0.0": true,
+	"crypto/internal/sysrand":        true,
 
 	// impl.Register is how the packages expose their alternative
 	// implementations to tests outside the module.
@@ -88,8 +89,7 @@ func TestImports(t *testing.T) {
 		}
 	}
 
-	// Ensure that all packages except check, check's dependencies, and the
-	// entropy source (which is used only from .../fips140/drbg) import check.
+	// Ensure that all packages except check and check's dependencies import check.
 	for pkg := range allPackages {
 		switch pkg {
 		case "crypto/internal/fips140/check":
@@ -100,7 +100,6 @@ func TestImports(t *testing.T) {
 		case "crypto/internal/fips140/sha3":
 		case "crypto/internal/fips140/sha256":
 		case "crypto/internal/fips140/sha512":
-		case "crypto/internal/fips140/entropy":
 		default:
 			if !importCheck[pkg] {
 				t.Errorf("package %s does not import crypto/internal/fips140/check", pkg)
diff --git a/src/crypto/internal/fips140test/entropy_test.go b/src/crypto/internal/fips140test/entropy_test.go
index a33e2e7bbc907d..cdaa4b7d8042eb 100644
--- a/src/crypto/internal/fips140test/entropy_test.go
+++ b/src/crypto/internal/fips140test/entropy_test.go
@@ -9,8 +9,8 @@ package fipstest
 import (
 	"bytes"
 	"crypto/internal/cryptotest"
+	entropy "crypto/internal/entropy/v1.0.0"
 	"crypto/internal/fips140/drbg"
-	"crypto/internal/fips140/entropy"
 	"crypto/rand"
 	"crypto/sha256"
 	"crypto/sha512"
@@ -217,7 +217,7 @@ func TestEntropyUnchanged(t *testing.T) {
 	testenv.MustHaveSource(t)
 
 	h := sha256.New()
-	root := os.DirFS("../fips140/entropy")
+	root := os.DirFS("../entropy/v1.0.0")
 	if err := fs.WalkDir(root, ".", func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			return err
@@ -237,13 +237,13 @@ func TestEntropyUnchanged(t *testing.T) {
 		t.Fatalf("WalkDir: %v", err)
 	}
 
-	// The crypto/internal/fips140/entropy package is certified as a FIPS 140-3
+	// The crypto/internal/entropy/v1.0.0 package is certified as a FIPS 140-3
 	// entropy source through the Entropy Source Validation program,
 	// independently of the FIPS 140-3 module. It must not change even across
 	// FIPS 140-3 module versions, in order to reuse the ESV certificate.
 	exp := "2541273241ae8aafe55026328354ed3799df1e2fb308b2097833203a42911b53"
 	if got := hex.EncodeToString(h.Sum(nil)); got != exp {
-		t.Errorf("hash of crypto/internal/fips140/entropy = %s, want %s", got, exp)
+		t.Errorf("hash of crypto/internal/entropy/v1.0.0 = %s, want %s", got, exp)
 	}
 }
 
diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index 8b14e6cb054c11..853605f5c29df2 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -490,13 +490,13 @@ var depsRules = `
 	time, internal/syscall/windows < crypto/internal/fips140deps/time;
 
 	crypto/internal/fips140deps/time, errors, math/bits, sync/atomic, unsafe
-	< crypto/internal/fips140/entropy;
+	< crypto/internal/entropy/v1.0.0;
 
 	STR, hash,
 	crypto/internal/impl,
 	crypto/internal/entropy,
 	crypto/internal/randutil,
-	crypto/internal/fips140/entropy,
+	crypto/internal/entropy/v1.0.0,
 	crypto/internal/fips140deps/byteorder,
 	crypto/internal/fips140deps/cpu,
 	crypto/internal/fips140deps/godebug

From 9a5a1202f4c4d5a7048b149b65c3e5b82a2de9aa Mon Sep 17 00:00:00 2001
From: Jorropo 
Date: Fri, 17 Oct 2025 19:51:53 +0200
Subject: [PATCH 206/229] runtime: clean dead architectures from go:build
 constraint

I've didn't caught theses while reviewing CL 701615.

Change-Id: I721978c173a255eb6d7c3e43dea2b903a9fd016d
Reviewed-on: https://go-review.googlesource.com/c/go/+/712740
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Jorropo 
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
Reviewed-by: David Chase 
---
 src/runtime/os_linux_futex32.go | 2 +-
 src/runtime/os_linux_futex64.go | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/runtime/os_linux_futex32.go b/src/runtime/os_linux_futex32.go
index fdf99e56693d0d..dbbd86cb3937e9 100644
--- a/src/runtime/os_linux_futex32.go
+++ b/src/runtime/os_linux_futex32.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && (386 || arm || mips || mipsle || ppc)
+//go:build linux && (386 || arm || mips || mipsle)
 
 package runtime
 
diff --git a/src/runtime/os_linux_futex64.go b/src/runtime/os_linux_futex64.go
index 487d0e03978b32..ce0b08c7ba7405 100644
--- a/src/runtime/os_linux_futex64.go
+++ b/src/runtime/os_linux_futex64.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux && !(386 || arm || mips || mipsle || ppc || s390)
+//go:build linux && !(386 || arm || mips || mipsle)
 
 package runtime
 

From b0dcb955421e1fe8021dbe23b8dd8d2b184da395 Mon Sep 17 00:00:00 2001
From: Jorropo 
Date: Sat, 18 Oct 2025 08:34:24 +0200
Subject: [PATCH 207/229] cmd/compile: leave the horses alone

I don't know why we were eliminating horses, this not cool.

Change-Id: I0d4b5a1b2f584e071de0a85ef88f9baf9183e12e
Reviewed-on: https://go-review.googlesource.com/c/go/+/712820
Reviewed-by: David Chase 
Auto-Submit: Jorropo 
Reviewed-by: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
---
 src/cmd/compile/internal/ssa/compile.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cmd/compile/internal/ssa/compile.go b/src/cmd/compile/internal/ssa/compile.go
index 1f47362583353e..c749ea9013d4c3 100644
--- a/src/cmd/compile/internal/ssa/compile.go
+++ b/src/cmd/compile/internal/ssa/compile.go
@@ -585,7 +585,7 @@ var passOrder = [...]constraint{
 	{"memcombine", "lower"},
 	// late opt transform some CondSelects into math.
 	{"branchelim", "late opt"},
-	// ranchelim is an arch-independent pass.
+	// branchelim is an arch-independent pass.
 	{"branchelim", "lower"},
 }
 

From 694182d77b1a0e3676214ad0e361bdbdafde33a1 Mon Sep 17 00:00:00 2001
From: Paul Murphy 
Date: Wed, 8 Oct 2025 14:34:09 -0500
Subject: [PATCH 208/229] cmd/internal/obj/ppc64: improve large prologue
 generation

Avoid needing an unsafe section to store LR and adjust SP
for large constants by using the stdux (MOVDU) instruction.

This is also a few instructions shorter as the large
constant adjustment is only created once.

Change-Id: I6ff7a24181cdadb1846a33129fc148dcf59b76d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/710197
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
Reviewed-by: David Chase 
Auto-Submit: Keith Randall 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/internal/obj/ppc64/obj9.go | 38 +++++++++++++-----------------
 1 file changed, 16 insertions(+), 22 deletions(-)

diff --git a/src/cmd/internal/obj/ppc64/obj9.go b/src/cmd/internal/obj/ppc64/obj9.go
index 5615b70aad4f0e..bae2965639721f 100644
--- a/src/cmd/internal/obj/ppc64/obj9.go
+++ b/src/cmd/internal/obj/ppc64/obj9.go
@@ -903,44 +903,38 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 					q.To.Reg = REGSP
 					q.Spadj = autosize
 				} else {
-					// Frame size is too large for a MOVDU instruction.
-					// Store link register before decrementing SP, so if a signal comes
-					// during the execution of the function prologue, the traceback
-					// code will not see a half-updated stack frame.
-					// This sequence is not async preemptible, as if we open a frame
-					// at the current SP, it will clobber the saved LR.
+					// Frame size is too large for an stdu MOVDU instruction, use stdux MOVDU.
 					q = obj.Appendp(q, c.newprog)
 					q.As = AMOVD
 					q.Pos = p.Pos
 					q.From.Type = obj.TYPE_REG
 					q.From.Reg = REG_LR
 					q.To.Type = obj.TYPE_REG
-					q.To.Reg = REG_R29 // REGTMP may be used to synthesize large offset in the next instruction
-
-					q = c.ctxt.StartUnsafePoint(q, c.newprog)
+					q.To.Reg = REG_R29
 
+					// Create stack adjustment in REGTMP
 					q = obj.Appendp(q, c.newprog)
 					q.As = AMOVD
 					q.Pos = p.Pos
-					q.From.Type = obj.TYPE_REG
-					q.From.Reg = REG_R29
-					q.To.Type = obj.TYPE_MEM
-					q.To.Offset = int64(-autosize)
-					q.To.Reg = REGSP
+					q.From.Type = obj.TYPE_CONST
+					q.From.Offset = int64(-autosize)
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGTMP
 
 					prologueEnd = q
 
+					// MOVDU R29, R31(R1)
 					q = obj.Appendp(q, c.newprog)
-					q.As = AADD
+					q.As = AMOVDU
 					q.Pos = p.Pos
-					q.From.Type = obj.TYPE_CONST
-					q.From.Offset = int64(-autosize)
-					q.To.Type = obj.TYPE_REG
-					q.To.Reg = REGSP
-					q.Spadj = +autosize
-
-					q = c.ctxt.EndUnsafePoint(q, c.newprog, -1)
+					q.From.Type = obj.TYPE_REG
+					q.From.Reg = REG_R29
+					q.To.Type = obj.TYPE_MEM
+					q.To.Reg = REGTMP
+					q.To.Index = REGSP
+					q.Spadj = autosize
 				}
+
 				prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
 			} else if c.cursym.Func().Text.Mark&LEAF == 0 {
 				// A very few functions that do not return to their caller

From a5a249d6a64508376320bc48546a6a43aebecda7 Mon Sep 17 00:00:00 2001
From: Jes Cok 
Date: Sun, 19 Oct 2025 19:53:27 +0000
Subject: [PATCH 209/229] all: eliminate unnecessary type conversions

Found by github.com/mdempsky/unconvert

Change-Id: I88ce10390a49ba768a4deaa0df9057c93c1164de
GitHub-Last-Rev: 3b0f7e8f74f58340637f33287c238765856b2483
GitHub-Pull-Request: golang/go#75974
Reviewed-on: https://go-review.googlesource.com/c/go/+/712940
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Auto-Submit: Keith Randall 
Reviewed-by: Keith Randall 
Reviewed-by: David Chase 
---
 src/cmd/asm/internal/asm/asm.go               |  6 +--
 src/cmd/cgo/gcc.go                            |  8 ++--
 src/cmd/cgo/internal/swig/swig_test.go        |  2 +-
 .../internal/testcarchive/carchive_test.go    |  4 +-
 .../cgo/internal/testcshared/cshared_test.go  |  2 +-
 .../cgo/internal/testerrors/badsym_test.go    |  2 +-
 src/cmd/compile/internal/coverage/cover.go    |  2 +-
 src/cmd/compile/internal/inline/inl.go        |  2 +-
 src/cmd/compile/internal/ir/bitset.go         |  2 +-
 src/cmd/compile/internal/loong64/ssa.go       |  4 +-
 src/cmd/compile/internal/noder/reader.go      |  2 +-
 src/cmd/compile/internal/ppc64/ssa.go         |  2 +-
 .../compile/internal/ssa/biasedsparsemap.go   |  2 +-
 src/cmd/compile/internal/ssa/debug.go         |  8 ++--
 src/cmd/compile/internal/ssa/magic_test.go    | 28 ++++++-------
 src/cmd/compile/internal/ssa/memcombine.go    |  2 +-
 src/cmd/compile/internal/ssa/rewrite.go       | 16 ++++----
 src/cmd/compile/internal/ssa/sccp.go          |  2 +-
 .../compile/internal/test/divconst_test.go    |  8 ++--
 src/cmd/go/internal/modindex/build.go         |  6 +--
 src/cmd/go/internal/vcs/vcs.go                |  2 +-
 src/cmd/go/internal/vet/vet.go                |  2 +-
 src/cmd/internal/buildid/rewrite.go           |  2 +-
 src/cmd/internal/goobj/objfile.go             | 10 ++---
 src/cmd/internal/obj/arm/a.out.go             |  2 +-
 src/cmd/internal/obj/arm64/asm7.go            | 18 ++++-----
 src/cmd/internal/obj/dwarf.go                 |  2 +-
 src/cmd/internal/obj/link.go                  |  4 +-
 src/cmd/internal/obj/loong64/a.out.go         |  2 +-
 src/cmd/internal/obj/mips/a.out.go            |  2 +-
 src/cmd/internal/obj/objfile.go               |  2 +-
 src/cmd/internal/obj/ppc64/a.out.go           |  2 +-
 src/cmd/internal/obj/ppc64/asm9.go            | 14 +++----
 src/cmd/internal/obj/riscv/obj.go             |  4 +-
 src/cmd/internal/obj/s390x/a.out.go           |  2 +-
 src/cmd/internal/obj/s390x/asmz.go            |  8 ++--
 src/cmd/internal/obj/s390x/rotate.go          |  2 +-
 src/cmd/internal/obj/x86/asm6.go              |  4 +-
 src/cmd/internal/obj/x86/asm_test.go          |  2 +-
 src/cmd/internal/objfile/goobj.go             |  4 +-
 src/cmd/internal/objfile/xcoff.go             |  4 +-
 src/cmd/link/internal/amd64/asm.go            |  2 +-
 src/cmd/link/internal/arm/asm.go              |  2 +-
 src/cmd/link/internal/arm64/asm.go            | 10 ++---
 src/cmd/link/internal/ld/data.go              | 10 ++---
 src/cmd/link/internal/ld/dwarf.go             | 40 +++++++++----------
 src/cmd/link/internal/ld/elf.go               | 22 +++++-----
 src/cmd/link/internal/ld/macho.go             |  6 +--
 src/cmd/link/internal/ld/pcln.go              |  8 ++--
 src/cmd/link/internal/ld/pe.go                |  4 +-
 src/cmd/link/internal/ld/xcoff.go             | 18 ++++-----
 src/cmd/link/internal/loadelf/ldelf.go        |  6 +--
 src/cmd/link/internal/loader/loader.go        | 10 ++---
 src/cmd/link/internal/loong64/asm.go          | 22 +++++-----
 src/cmd/link/internal/mips64/asm.go           |  8 ++--
 src/cmd/link/internal/ppc64/asm.go            |  4 +-
 src/cmd/link/internal/riscv64/asm.go          |  6 +--
 src/cmd/link/internal/wasm/asm.go             |  4 +-
 src/cmd/trace/gstate.go                       |  2 +-
 src/net/cgo_unix_syscall.go                   |  3 +-
 src/runtime/metrics.go                        | 14 +++----
 61 files changed, 202 insertions(+), 203 deletions(-)

diff --git a/src/cmd/asm/internal/asm/asm.go b/src/cmd/asm/internal/asm/asm.go
index 389307af29ea53..0f75edf4e5d254 100644
--- a/src/cmd/asm/internal/asm/asm.go
+++ b/src/cmd/asm/internal/asm/asm.go
@@ -248,7 +248,7 @@ func (p *Parser) asmData(operands [][]lex.Token) {
 	case obj.TYPE_CONST:
 		switch sz {
 		case 1, 2, 4, 8:
-			nameAddr.Sym.WriteInt(p.ctxt, nameAddr.Offset, int(sz), valueAddr.Offset)
+			nameAddr.Sym.WriteInt(p.ctxt, nameAddr.Offset, sz, valueAddr.Offset)
 		default:
 			p.errorf("bad int size for DATA argument: %d", sz)
 		}
@@ -262,10 +262,10 @@ func (p *Parser) asmData(operands [][]lex.Token) {
 			p.errorf("bad float size for DATA argument: %d", sz)
 		}
 	case obj.TYPE_SCONST:
-		nameAddr.Sym.WriteString(p.ctxt, nameAddr.Offset, int(sz), valueAddr.Val.(string))
+		nameAddr.Sym.WriteString(p.ctxt, nameAddr.Offset, sz, valueAddr.Val.(string))
 	case obj.TYPE_ADDR:
 		if sz == p.arch.PtrSize {
-			nameAddr.Sym.WriteAddr(p.ctxt, nameAddr.Offset, int(sz), valueAddr.Sym, valueAddr.Offset)
+			nameAddr.Sym.WriteAddr(p.ctxt, nameAddr.Offset, sz, valueAddr.Sym, valueAddr.Offset)
 		} else {
 			p.errorf("bad addr size for DATA argument: %d", sz)
 		}
diff --git a/src/cmd/cgo/gcc.go b/src/cmd/cgo/gcc.go
index 6c1695bdb0a613..886ddf2d461b65 100644
--- a/src/cmd/cgo/gcc.go
+++ b/src/cmd/cgo/gcc.go
@@ -2154,7 +2154,7 @@ func (p *Package) gccDebug(stdin []byte, nnames int) (d *dwarf.Data, ints []int6
 		for _, s := range f.Symbols {
 			switch {
 			case isDebugInts(s.Name):
-				if i := int(s.SectionNumber) - 1; 0 <= i && i < len(f.Sections) {
+				if i := s.SectionNumber - 1; 0 <= i && i < len(f.Sections) {
 					sect := f.Sections[i]
 					if s.Value < sect.Size {
 						if sdat, err := sect.Data(); err == nil {
@@ -2167,7 +2167,7 @@ func (p *Package) gccDebug(stdin []byte, nnames int) (d *dwarf.Data, ints []int6
 					}
 				}
 			case isDebugFloats(s.Name):
-				if i := int(s.SectionNumber) - 1; 0 <= i && i < len(f.Sections) {
+				if i := s.SectionNumber - 1; 0 <= i && i < len(f.Sections) {
 					sect := f.Sections[i]
 					if s.Value < sect.Size {
 						if sdat, err := sect.Data(); err == nil {
@@ -2181,7 +2181,7 @@ func (p *Package) gccDebug(stdin []byte, nnames int) (d *dwarf.Data, ints []int6
 				}
 			default:
 				if n := indexOfDebugStr(s.Name); n != -1 {
-					if i := int(s.SectionNumber) - 1; 0 <= i && i < len(f.Sections) {
+					if i := s.SectionNumber - 1; 0 <= i && i < len(f.Sections) {
 						sect := f.Sections[i]
 						if s.Value < sect.Size {
 							if sdat, err := sect.Data(); err == nil {
@@ -2193,7 +2193,7 @@ func (p *Package) gccDebug(stdin []byte, nnames int) (d *dwarf.Data, ints []int6
 					break
 				}
 				if n := indexOfDebugStrlen(s.Name); n != -1 {
-					if i := int(s.SectionNumber) - 1; 0 <= i && i < len(f.Sections) {
+					if i := s.SectionNumber - 1; 0 <= i && i < len(f.Sections) {
 						sect := f.Sections[i]
 						if s.Value < sect.Size {
 							if sdat, err := sect.Data(); err == nil {
diff --git a/src/cmd/cgo/internal/swig/swig_test.go b/src/cmd/cgo/internal/swig/swig_test.go
index 603dab4917c263..9d5ea0051ac62c 100644
--- a/src/cmd/cgo/internal/swig/swig_test.go
+++ b/src/cmd/cgo/internal/swig/swig_test.go
@@ -80,7 +80,7 @@ func mustHaveCxx(t *testing.T) {
 	if len(args) == 0 {
 		t.Skip("no C++ compiler")
 	}
-	testenv.MustHaveExecPath(t, string(args[0]))
+	testenv.MustHaveExecPath(t, args[0])
 }
 
 var (
diff --git a/src/cmd/cgo/internal/testcarchive/carchive_test.go b/src/cmd/cgo/internal/testcarchive/carchive_test.go
index c0ad79f23144a7..7c6e2b1d848def 100644
--- a/src/cmd/cgo/internal/testcarchive/carchive_test.go
+++ b/src/cmd/cgo/internal/testcarchive/carchive_test.go
@@ -102,14 +102,14 @@ func testMain(m *testing.M) int {
 	bin = cmdToRun("./testp")
 
 	ccOut := goEnv("CC")
-	cc = []string{string(ccOut)}
+	cc = []string{ccOut}
 
 	out := goEnv("GOGCCFLAGS")
 	quote := '\000'
 	start := 0
 	lastSpace := true
 	backslash := false
-	s := string(out)
+	s := out
 	for i, c := range s {
 		if quote == '\000' && unicode.IsSpace(c) {
 			if !lastSpace {
diff --git a/src/cmd/cgo/internal/testcshared/cshared_test.go b/src/cmd/cgo/internal/testcshared/cshared_test.go
index 2ce705adba44f3..c01f5cf2cfbe7a 100644
--- a/src/cmd/cgo/internal/testcshared/cshared_test.go
+++ b/src/cmd/cgo/internal/testcshared/cshared_test.go
@@ -76,7 +76,7 @@ func testMain(m *testing.M) int {
 	start := 0
 	lastSpace := true
 	backslash := false
-	s := string(out)
+	s := out
 	for i, c := range s {
 		if quote == '\000' && unicode.IsSpace(c) {
 			if !lastSpace {
diff --git a/src/cmd/cgo/internal/testerrors/badsym_test.go b/src/cmd/cgo/internal/testerrors/badsym_test.go
index 4fd5c44505aa78..756ffdb1fc787e 100644
--- a/src/cmd/cgo/internal/testerrors/badsym_test.go
+++ b/src/cmd/cgo/internal/testerrors/badsym_test.go
@@ -186,7 +186,7 @@ func cCompilerCmd(t *testing.T) []string {
 	start := 0
 	lastSpace := true
 	backslash := false
-	s := string(out)
+	s := out
 	for i, c := range s {
 		if quote == '\000' && unicode.IsSpace(c) {
 			if !lastSpace {
diff --git a/src/cmd/compile/internal/coverage/cover.go b/src/cmd/compile/internal/coverage/cover.go
index 51f934f060099f..5ecd5271f617e2 100644
--- a/src/cmd/compile/internal/coverage/cover.go
+++ b/src/cmd/compile/internal/coverage/cover.go
@@ -131,7 +131,7 @@ func metaHashAndLen() ([16]byte, int) {
 	}
 	var hv [16]byte
 	for i := 0; i < 16; i++ {
-		nib := string(mhash[i*2 : i*2+2])
+		nib := mhash[i*2 : i*2+2]
 		x, err := strconv.ParseInt(nib, 16, 32)
 		if err != nil {
 			base.Fatalf("metahash bad byte %q", nib)
diff --git a/src/cmd/compile/internal/inline/inl.go b/src/cmd/compile/internal/inline/inl.go
index 9f03f6404a5f69..3a9243e0291f5e 100644
--- a/src/cmd/compile/internal/inline/inl.go
+++ b/src/cmd/compile/internal/inline/inl.go
@@ -289,7 +289,7 @@ func CanInline(fn *ir.Func, profile *pgoir.Profile) {
 // function is inlinable.
 func noteInlinableFunc(n *ir.Name, fn *ir.Func, cost int32) {
 	if base.Flag.LowerM > 1 {
-		fmt.Printf("%v: can inline %v with cost %d as: %v { %v }\n", ir.Line(fn), n, cost, fn.Type(), ir.Nodes(fn.Body))
+		fmt.Printf("%v: can inline %v with cost %d as: %v { %v }\n", ir.Line(fn), n, cost, fn.Type(), fn.Body)
 	} else if base.Flag.LowerM != 0 {
 		fmt.Printf("%v: can inline %v\n", ir.Line(fn), n)
 	}
diff --git a/src/cmd/compile/internal/ir/bitset.go b/src/cmd/compile/internal/ir/bitset.go
index bae400586695b7..339e4e524f1df9 100644
--- a/src/cmd/compile/internal/ir/bitset.go
+++ b/src/cmd/compile/internal/ir/bitset.go
@@ -23,7 +23,7 @@ func (f *bitset8) set2(shift uint8, b uint8) {
 	// Clear old bits.
 	*(*uint8)(f) &^= 3 << shift
 	// Set new bits.
-	*(*uint8)(f) |= uint8(b&3) << shift
+	*(*uint8)(f) |= (b & 3) << shift
 }
 
 type bitset16 uint16
diff --git a/src/cmd/compile/internal/loong64/ssa.go b/src/cmd/compile/internal/loong64/ssa.go
index bd0d96a6954957..5e554282839d2e 100644
--- a/src/cmd/compile/internal/loong64/ssa.go
+++ b/src/cmd/compile/internal/loong64/ssa.go
@@ -1175,8 +1175,8 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.From.Type = obj.TYPE_MEM
 		p.From.Reg = v.Args[0].Reg()
 		p.AddRestSourceArgs([]obj.Addr{
-			{Type: obj.TYPE_CONST, Offset: int64((v.AuxInt >> 5) & 0x1fffffffff)},
-			{Type: obj.TYPE_CONST, Offset: int64((v.AuxInt >> 0) & 0x1f)},
+			{Type: obj.TYPE_CONST, Offset: (v.AuxInt >> 5) & 0x1fffffffff},
+			{Type: obj.TYPE_CONST, Offset: (v.AuxInt >> 0) & 0x1f},
 		})
 
 	case ssa.OpLOONG64ADDshiftLLV:
diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index a8a45b02697079..d7dd58d8caafe8 100644
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -3577,7 +3577,7 @@ func unifiedInlineCall(callerfn *ir.Func, call *ir.CallExpr, fn *ir.Func, inlInd
 		edit(r.curfn)
 	})
 
-	body := ir.Nodes(r.curfn.Body)
+	body := r.curfn.Body
 
 	// Reparent any declarations into the caller function.
 	for _, name := range r.curfn.Dcl {
diff --git a/src/cmd/compile/internal/ppc64/ssa.go b/src/cmd/compile/internal/ppc64/ssa.go
index ace3024480e253..f0d228559f3a87 100644
--- a/src/cmd/compile/internal/ppc64/ssa.go
+++ b/src/cmd/compile/internal/ppc64/ssa.go
@@ -631,7 +631,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p := s.Prog(v.Op.Asm())
 		p.To = obj.Addr{Type: obj.TYPE_REG, Reg: v.Reg()}
 		p.Reg = v.Args[0].Reg()
-		p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: int64(sh)}
+		p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: sh}
 		p.AddRestSourceArgs([]obj.Addr{{Type: obj.TYPE_CONST, Offset: mb}, {Type: obj.TYPE_CONST, Offset: me}})
 		// Auxint holds mask
 
diff --git a/src/cmd/compile/internal/ssa/biasedsparsemap.go b/src/cmd/compile/internal/ssa/biasedsparsemap.go
index 25fbaf68625753..a8bda831b1f73b 100644
--- a/src/cmd/compile/internal/ssa/biasedsparsemap.go
+++ b/src/cmd/compile/internal/ssa/biasedsparsemap.go
@@ -31,7 +31,7 @@ func (s *biasedSparseMap) cap() int {
 	if s == nil || s.s == nil {
 		return 0
 	}
-	return s.s.cap() + int(s.first)
+	return s.s.cap() + s.first
 }
 
 // size returns the number of entries stored in s
diff --git a/src/cmd/compile/internal/ssa/debug.go b/src/cmd/compile/internal/ssa/debug.go
index c9a3e4291cc1a6..7edc414bda7eb7 100644
--- a/src/cmd/compile/internal/ssa/debug.go
+++ b/src/cmd/compile/internal/ssa/debug.go
@@ -1553,11 +1553,11 @@ func (debugInfo *FuncDebug) PutLocationListDwarf4(list []byte, ctxt *obj.Link, l
 		}
 
 		if ctxt.UseBASEntries {
-			listSym.WriteInt(ctxt, listSym.Size, ctxt.Arch.PtrSize, int64(begin))
-			listSym.WriteInt(ctxt, listSym.Size, ctxt.Arch.PtrSize, int64(end))
+			listSym.WriteInt(ctxt, listSym.Size, ctxt.Arch.PtrSize, begin)
+			listSym.WriteInt(ctxt, listSym.Size, ctxt.Arch.PtrSize, end)
 		} else {
-			listSym.WriteCURelativeAddr(ctxt, listSym.Size, startPC, int64(begin))
-			listSym.WriteCURelativeAddr(ctxt, listSym.Size, startPC, int64(end))
+			listSym.WriteCURelativeAddr(ctxt, listSym.Size, startPC, begin)
+			listSym.WriteCURelativeAddr(ctxt, listSym.Size, startPC, end)
 		}
 
 		i += 2 * ctxt.Arch.PtrSize
diff --git a/src/cmd/compile/internal/ssa/magic_test.go b/src/cmd/compile/internal/ssa/magic_test.go
index 7c6009dea6c83b..44177d679e7e8e 100644
--- a/src/cmd/compile/internal/ssa/magic_test.go
+++ b/src/cmd/compile/internal/ssa/magic_test.go
@@ -33,7 +33,7 @@ func testMagicExhaustive(t *testing.T, n uint) {
 	min := -int64(1) << (n - 1)
 	max := int64(1) << (n - 1)
 	for c := int64(1); c < max; c++ {
-		if !smagicOK(n, int64(c)) {
+		if !smagicOK(n, c) {
 			continue
 		}
 		m := int64(smagic(n, c).m)
@@ -164,11 +164,11 @@ func TestMagicSigned(t *testing.T) {
 			if c>>(n-1) != 0 {
 				continue // not appropriate for the given n.
 			}
-			if !smagicOK(n, int64(c)) {
+			if !smagicOK(n, c) {
 				t.Errorf("expected n=%d c=%d to pass\n", n, c)
 			}
-			m := smagic(n, int64(c)).m
-			s := smagic(n, int64(c)).s
+			m := smagic(n, c).m
+			s := smagic(n, c).s
 
 			C := new(big.Int).SetInt64(c)
 			M := new(big.Int).SetUint64(m)
@@ -308,13 +308,13 @@ func testDivisibleExhaustive(t *testing.T, n uint) {
 	minI := -int64(1) << (n - 1)
 	maxI := int64(1) << (n - 1)
 	for c := int64(1); c < maxI; c++ {
-		if !sdivisibleOK(n, int64(c)) {
+		if !sdivisibleOK(n, c) {
 			continue
 		}
-		k := sdivisible(n, int64(c)).k
-		m := sdivisible(n, int64(c)).m
-		a := sdivisible(n, int64(c)).a
-		max := sdivisible(n, int64(c)).max
+		k := sdivisible(n, c).k
+		m := sdivisible(n, c).m
+		a := sdivisible(n, c).a
+		max := sdivisible(n, c).max
 		mask := ^uint64(0) >> (64 - n)
 		for i := minI; i < maxI; i++ {
 			want := i%c == 0
@@ -369,13 +369,13 @@ func TestDivisibleSigned(t *testing.T) {
 			if c>>(n-1) != 0 {
 				continue // not appropriate for the given n.
 			}
-			if !sdivisibleOK(n, int64(c)) {
+			if !sdivisibleOK(n, c) {
 				t.Errorf("expected n=%d c=%d to pass\n", n, c)
 			}
-			k := sdivisible(n, int64(c)).k
-			m := sdivisible(n, int64(c)).m
-			a := sdivisible(n, int64(c)).a
-			max := sdivisible(n, int64(c)).max
+			k := sdivisible(n, c).k
+			m := sdivisible(n, c).m
+			a := sdivisible(n, c).a
+			max := sdivisible(n, c).max
 			mask := ^uint64(0) >> (64 - n)
 
 			C := new(big.Int).SetInt64(c)
diff --git a/src/cmd/compile/internal/ssa/memcombine.go b/src/cmd/compile/internal/ssa/memcombine.go
index b8fcd3949595cd..6b1df7dc099e73 100644
--- a/src/cmd/compile/internal/ssa/memcombine.go
+++ b/src/cmd/compile/internal/ssa/memcombine.go
@@ -728,7 +728,7 @@ func combineStores(root *Value) {
 	if isLittleEndian && shift0 != 0 {
 		sv = rightShift(root.Block, root.Pos, sv, shift0)
 	}
-	shiftedSize = int64(aTotalSize - a[0].size)
+	shiftedSize = aTotalSize - a[0].size
 	if isBigEndian && shift0-shiftedSize*8 != 0 {
 		sv = rightShift(root.Block, root.Pos, sv, shift0-shiftedSize*8)
 	}
diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go
index f02019df384f5f..9ea735a67d4b7f 100644
--- a/src/cmd/compile/internal/ssa/rewrite.go
+++ b/src/cmd/compile/internal/ssa/rewrite.go
@@ -726,7 +726,7 @@ func int32ToAuxInt(i int32) int64 {
 	return int64(i)
 }
 func int64ToAuxInt(i int64) int64 {
-	return int64(i)
+	return i
 }
 func uint8ToAuxInt(i uint8) int64 {
 	return int64(int8(i))
@@ -1603,7 +1603,7 @@ func encodePPC64RotateMask(rotate, mask, nbits int64) int64 {
 		mb, me = men, mbn
 	}
 
-	return int64(me) | int64(mb<<8) | int64(rotate<<16) | int64(nbits<<24)
+	return int64(me) | int64(mb<<8) | rotate<<16 | nbits<<24
 }
 
 // Merge (RLDICL [encoded] (SRDconst [s] x)) into (RLDICL [new_encoded] x)
@@ -1712,7 +1712,7 @@ func mergePPC64AndSldi(m, s int64) int64 {
 func mergePPC64ClrlsldiSrw(sld, srw int64) int64 {
 	mask_1 := uint64(0xFFFFFFFF >> uint(srw))
 	// for CLRLSLDI, it's more convenient to think of it as a mask left bits then rotate left.
-	mask_2 := uint64(0xFFFFFFFFFFFFFFFF) >> uint(GetPPC64Shiftmb(int64(sld)))
+	mask_2 := uint64(0xFFFFFFFFFFFFFFFF) >> uint(GetPPC64Shiftmb(sld))
 
 	// Rewrite mask to apply after the final left shift.
 	mask_3 := (mask_1 & mask_2) << uint(GetPPC64Shiftsh(sld))
@@ -1724,7 +1724,7 @@ func mergePPC64ClrlsldiSrw(sld, srw int64) int64 {
 	if uint64(uint32(mask_3)) != mask_3 || mask_3 == 0 {
 		return 0
 	}
-	return encodePPC64RotateMask(int64(r_3), int64(mask_3), 32)
+	return encodePPC64RotateMask(r_3, int64(mask_3), 32)
 }
 
 // Test if a doubleword shift right feeding into a CLRLSLDI can be merged into RLWINM.
@@ -1732,7 +1732,7 @@ func mergePPC64ClrlsldiSrw(sld, srw int64) int64 {
 func mergePPC64ClrlsldiSrd(sld, srd int64) int64 {
 	mask_1 := uint64(0xFFFFFFFFFFFFFFFF) >> uint(srd)
 	// for CLRLSLDI, it's more convenient to think of it as a mask left bits then rotate left.
-	mask_2 := uint64(0xFFFFFFFFFFFFFFFF) >> uint(GetPPC64Shiftmb(int64(sld)))
+	mask_2 := uint64(0xFFFFFFFFFFFFFFFF) >> uint(GetPPC64Shiftmb(sld))
 
 	// Rewrite mask to apply after the final left shift.
 	mask_3 := (mask_1 & mask_2) << uint(GetPPC64Shiftsh(sld))
@@ -1749,7 +1749,7 @@ func mergePPC64ClrlsldiSrd(sld, srd int64) int64 {
 	if v1&mask_3 != 0 {
 		return 0
 	}
-	return encodePPC64RotateMask(int64(r_3&31), int64(mask_3), 32)
+	return encodePPC64RotateMask(r_3&31, int64(mask_3), 32)
 }
 
 // Test if a RLWINM feeding into a CLRLSLDI can be merged into RLWINM.  Return
@@ -2155,11 +2155,11 @@ func rewriteFixedLoad(v *Value, sym Sym, sb *Value, off int64) *Value {
 				switch f.Sym.Name {
 				case "Size_":
 					v.reset(ptrSizedOpConst)
-					v.AuxInt = int64(t.Size())
+					v.AuxInt = t.Size()
 					return v
 				case "PtrBytes":
 					v.reset(ptrSizedOpConst)
-					v.AuxInt = int64(types.PtrDataSize(t))
+					v.AuxInt = types.PtrDataSize(t)
 					return v
 				case "Hash":
 					v.reset(OpConst32)
diff --git a/src/cmd/compile/internal/ssa/sccp.go b/src/cmd/compile/internal/ssa/sccp.go
index ecc0f94e5b96b6..107db23ed4af08 100644
--- a/src/cmd/compile/internal/ssa/sccp.go
+++ b/src/cmd/compile/internal/ssa/sccp.go
@@ -377,7 +377,7 @@ func (t *worklist) visitValue(val *Value) {
 		// re-visit all uses of value if its lattice is changed
 		newLt := t.getLatticeCell(val)
 		if !equals(newLt, oldLt) {
-			if int8(oldLt.tag) > int8(newLt.tag) {
+			if oldLt.tag > newLt.tag {
 				t.f.Fatalf("Must lower lattice\n")
 			}
 			t.addUses(val)
diff --git a/src/cmd/compile/internal/test/divconst_test.go b/src/cmd/compile/internal/test/divconst_test.go
index 9358a60374996a..5e89ce9a3d30b8 100644
--- a/src/cmd/compile/internal/test/divconst_test.go
+++ b/src/cmd/compile/internal/test/divconst_test.go
@@ -99,28 +99,28 @@ func BenchmarkDivconstU64(b *testing.B) {
 		x := uint64(123456789123456789)
 		for i := 0; i < b.N; i++ {
 			x += x << 4
-			u64res = uint64(x) / 3
+			u64res = x / 3
 		}
 	})
 	b.Run("5", func(b *testing.B) {
 		x := uint64(123456789123456789)
 		for i := 0; i < b.N; i++ {
 			x += x << 4
-			u64res = uint64(x) / 5
+			u64res = x / 5
 		}
 	})
 	b.Run("37", func(b *testing.B) {
 		x := uint64(123456789123456789)
 		for i := 0; i < b.N; i++ {
 			x += x << 4
-			u64res = uint64(x) / 37
+			u64res = x / 37
 		}
 	})
 	b.Run("1234567", func(b *testing.B) {
 		x := uint64(123456789123456789)
 		for i := 0; i < b.N; i++ {
 			x += x << 4
-			u64res = uint64(x) / 1234567
+			u64res = x / 1234567
 		}
 	})
 }
diff --git a/src/cmd/go/internal/modindex/build.go b/src/cmd/go/internal/modindex/build.go
index 0fa78afe2c08ef..053e04dfe599e9 100644
--- a/src/cmd/go/internal/modindex/build.go
+++ b/src/cmd/go/internal/modindex/build.go
@@ -296,9 +296,9 @@ func cleanDecls(m map[string][]token.Position) ([]string, map[string][]token.Pos
 }
 
 var (
-	bSlashSlash = []byte(slashSlash)
-	bStarSlash  = []byte(starSlash)
-	bSlashStar  = []byte(slashStar)
+	bSlashSlash = slashSlash
+	bStarSlash  = starSlash
+	bSlashStar  = slashStar
 	bPlusBuild  = []byte("+build")
 
 	goBuildComment = []byte("//go:build")
diff --git a/src/cmd/go/internal/vcs/vcs.go b/src/cmd/go/internal/vcs/vcs.go
index edbc5734401737..7c198c5f2b442a 100644
--- a/src/cmd/go/internal/vcs/vcs.go
+++ b/src/cmd/go/internal/vcs/vcs.go
@@ -237,7 +237,7 @@ func parseRevTime(out []byte) (string, time.Time, error) {
 	}
 	rev := buf[:i]
 
-	secs, err := strconv.ParseInt(string(buf[i+1:]), 10, 64)
+	secs, err := strconv.ParseInt(buf[i+1:], 10, 64)
 	if err != nil {
 		return "", time.Time{}, fmt.Errorf("unrecognized VCS tool output: %v", err)
 	}
diff --git a/src/cmd/go/internal/vet/vet.go b/src/cmd/go/internal/vet/vet.go
index 4de71bcdb9b948..c5ba3ae110d8c3 100644
--- a/src/cmd/go/internal/vet/vet.go
+++ b/src/cmd/go/internal/vet/vet.go
@@ -281,7 +281,7 @@ func printJSONDiagnostics(r io.Reader) error {
 		// unitchecker emits a JSON map of the form:
 		// output maps Package ID -> Analyzer.Name -> (error | []Diagnostic);
 		var tree jsonTree
-		if err := json.Unmarshal([]byte(stdout), &tree); err != nil {
+		if err := json.Unmarshal(stdout, &tree); err != nil {
 			return fmt.Errorf("parsing JSON: %v", err)
 		}
 		for _, units := range tree {
diff --git a/src/cmd/internal/buildid/rewrite.go b/src/cmd/internal/buildid/rewrite.go
index 5300f7f9b883ca..cee40b0116d01a 100644
--- a/src/cmd/internal/buildid/rewrite.go
+++ b/src/cmd/internal/buildid/rewrite.go
@@ -213,7 +213,7 @@ func findHostBuildID(r io.Reader) (offset int64, size int64, ok bool) {
 		if cmd.Cmd == imacho.LC_UUID {
 			// The UUID is the data in the LC_UUID load command,
 			// skipping over the 8-byte command header.
-			return int64(reader.Offset() + 8), int64(cmd.Len - 8), true
+			return reader.Offset() + 8, int64(cmd.Len - 8), true
 		}
 	}
 	return 0, 0, false
diff --git a/src/cmd/internal/goobj/objfile.go b/src/cmd/internal/goobj/objfile.go
index 38da67076d5bb2..cca3c840e0e9dc 100644
--- a/src/cmd/internal/goobj/objfile.go
+++ b/src/cmd/internal/goobj/objfile.go
@@ -727,7 +727,7 @@ func (r *Reader) NNonpkgref() int {
 
 // SymOff returns the offset of the i-th symbol.
 func (r *Reader) SymOff(i uint32) uint32 {
-	return r.h.Offsets[BlkSymdef] + uint32(i*SymSize)
+	return r.h.Offsets[BlkSymdef] + i*SymSize
 }
 
 // Sym returns a pointer to the i-th symbol.
@@ -752,7 +752,7 @@ func (r *Reader) RefFlags(i int) *RefFlags {
 // Note: here i is the index of short hashed symbols, not all symbols
 // (unlike other accessors).
 func (r *Reader) Hash64(i uint32) uint64 {
-	off := r.h.Offsets[BlkHash64] + uint32(i*Hash64Size)
+	off := r.h.Offsets[BlkHash64] + i*Hash64Size
 	return r.uint64At(off)
 }
 
@@ -760,19 +760,19 @@ func (r *Reader) Hash64(i uint32) uint64 {
 // Note: here i is the index of hashed symbols, not all symbols
 // (unlike other accessors).
 func (r *Reader) Hash(i uint32) *HashType {
-	off := r.h.Offsets[BlkHash] + uint32(i*HashSize)
+	off := r.h.Offsets[BlkHash] + i*HashSize
 	return (*HashType)(unsafe.Pointer(&r.b[off]))
 }
 
 // NReloc returns the number of relocations of the i-th symbol.
 func (r *Reader) NReloc(i uint32) int {
-	relocIdxOff := r.h.Offsets[BlkRelocIdx] + uint32(i*4)
+	relocIdxOff := r.h.Offsets[BlkRelocIdx] + i*4
 	return int(r.uint32At(relocIdxOff+4) - r.uint32At(relocIdxOff))
 }
 
 // RelocOff returns the offset of the j-th relocation of the i-th symbol.
 func (r *Reader) RelocOff(i uint32, j int) uint32 {
-	relocIdxOff := r.h.Offsets[BlkRelocIdx] + uint32(i*4)
+	relocIdxOff := r.h.Offsets[BlkRelocIdx] + i*4
 	relocIdx := r.uint32At(relocIdxOff)
 	return r.h.Offsets[BlkReloc] + (relocIdx+uint32(j))*uint32(RelocSize)
 }
diff --git a/src/cmd/internal/obj/arm/a.out.go b/src/cmd/internal/obj/arm/a.out.go
index fabd0cb50f43be..d33b75120d2fc5 100644
--- a/src/cmd/internal/obj/arm/a.out.go
+++ b/src/cmd/internal/obj/arm/a.out.go
@@ -115,7 +115,7 @@ var ARMDWARFRegisters = map[int16]int16{}
 func init() {
 	// f assigns dwarfregisters[from:to] = (base):(step*(to-from)+base)
 	f := func(from, to, base, step int16) {
-		for r := int16(from); r <= to; r++ {
+		for r := from; r <= to; r++ {
 			ARMDWARFRegisters[r] = step*(r-from) + base
 		}
 	}
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index 3cb4be436b9b7f..befd1bee13d66f 100644
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -1163,7 +1163,7 @@ func span7(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 		switch p.As {
 		case obj.APCALIGN, obj.APCALIGNMAX:
 			v := obj.AlignmentPaddingLength(int32(p.Pc), p, c.ctxt)
-			for i := 0; i < int(v/4); i++ {
+			for i := 0; i < v/4; i++ {
 				// emit ANOOP instruction by the padding size
 				buf.emit(OP_NOOP)
 			}
@@ -4017,7 +4017,7 @@ func (c *ctxt7) asmout(p *obj.Prog, out []uint32) (count int) {
 
 		// Handle smaller unaligned and negative offsets via addition or subtraction.
 		if v >= -4095 && v <= 4095 {
-			o1 = c.oaddi12(p, v, REGTMP, int16(rt))
+			o1 = c.oaddi12(p, v, REGTMP, rt)
 			o2 = c.olsr12u(p, c.opstr(p, p.As), 0, REGTMP, rf)
 			break
 		}
@@ -4073,7 +4073,7 @@ func (c *ctxt7) asmout(p *obj.Prog, out []uint32) (count int) {
 
 		// Handle smaller unaligned and negative offsets via addition or subtraction.
 		if v >= -4095 && v <= 4095 {
-			o1 = c.oaddi12(p, v, REGTMP, int16(rf))
+			o1 = c.oaddi12(p, v, REGTMP, rf)
 			o2 = c.olsr12u(p, c.opldr(p, p.As), 0, REGTMP, rt)
 			break
 		}
@@ -4852,7 +4852,7 @@ func (c *ctxt7) asmout(p *obj.Prog, out []uint32) (count int) {
 		if p.Pool != nil {
 			c.ctxt.Diag("%v: unused constant in pool (%v)\n", p, v)
 		}
-		o1 = c.oaddi(p, AADD, lo, REGTMP, int16(rf))
+		o1 = c.oaddi(p, AADD, lo, REGTMP, rf)
 		o2 = c.oaddi(p, AADD, hi, REGTMP, REGTMP)
 		o3 = c.opldpstp(p, o, 0, REGTMP, rt1, rt2, 1)
 		break
@@ -4917,7 +4917,7 @@ func (c *ctxt7) asmout(p *obj.Prog, out []uint32) (count int) {
 		if p.Pool != nil {
 			c.ctxt.Diag("%v: unused constant in pool (%v)\n", p, v)
 		}
-		o1 = c.oaddi(p, AADD, lo, REGTMP, int16(rt))
+		o1 = c.oaddi(p, AADD, lo, REGTMP, rt)
 		o2 = c.oaddi(p, AADD, hi, REGTMP, REGTMP)
 		o3 = c.opldpstp(p, o, 0, REGTMP, rf1, rf2, 0)
 		break
@@ -5293,7 +5293,7 @@ func (c *ctxt7) asmout(p *obj.Prog, out []uint32) (count int) {
 		}
 
 		o1 = c.opirr(p, p.As)
-		o1 |= (uint32(r&31) << 5) | (uint32((imm>>3)&0xfff) << 10) | (uint32(v & 31))
+		o1 |= (uint32(r&31) << 5) | ((imm >> 3) & 0xfff << 10) | (v & 31)
 
 	case 92: /* vmov Vn.[index], Vd.[index] */
 		rf := int(p.From.Reg)
@@ -5846,7 +5846,7 @@ func (c *ctxt7) asmout(p *obj.Prog, out []uint32) (count int) {
 	out[3] = o4
 	out[4] = o5
 
-	return int(o.size(c.ctxt, p) / 4)
+	return o.size(c.ctxt, p) / 4
 }
 
 func (c *ctxt7) addrRelocType(p *obj.Prog) objabi.RelocType {
@@ -7854,12 +7854,12 @@ func (c *ctxt7) encRegShiftOrExt(p *obj.Prog, a *obj.Addr, r int16) uint32 {
 
 // pack returns the encoding of the "Q" field and two arrangement specifiers.
 func pack(q uint32, arngA, arngB uint8) uint32 {
-	return uint32(q)<<16 | uint32(arngA)<<8 | uint32(arngB)
+	return q<<16 | uint32(arngA)<<8 | uint32(arngB)
 }
 
 // ARM64RegisterExtension constructs an ARM64 register with extension or arrangement.
 func ARM64RegisterExtension(a *obj.Addr, ext string, reg, num int16, isAmount, isIndex bool) error {
-	Rnum := (reg & 31) + int16(num<<5)
+	Rnum := (reg & 31) + num<<5
 	if isAmount {
 		if num < 0 || num > 7 {
 			return errors.New("index shift amount is out of range")
diff --git a/src/cmd/internal/obj/dwarf.go b/src/cmd/internal/obj/dwarf.go
index c6f321e3e53153..670b0f3510f8c2 100644
--- a/src/cmd/internal/obj/dwarf.go
+++ b/src/cmd/internal/obj/dwarf.go
@@ -219,7 +219,7 @@ func (c dwCtxt) AddUint16(s dwarf.Sym, i uint16) {
 	c.AddInt(s, 2, int64(i))
 }
 func (c dwCtxt) AddUint8(s dwarf.Sym, i uint8) {
-	b := []byte{byte(i)}
+	b := []byte{i}
 	c.AddBytes(s, b)
 }
 func (c dwCtxt) AddBytes(s dwarf.Sym, b []byte) {
diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index b7e116bae39dc4..9f3814e748aa5f 100644
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -753,12 +753,12 @@ func (ft *WasmFuncType) Read(b []byte) {
 	ft.Params = make([]WasmField, readUint32())
 	for i := range ft.Params {
 		ft.Params[i].Type = WasmFieldType(readByte())
-		ft.Params[i].Offset = int64(readInt64())
+		ft.Params[i].Offset = readInt64()
 	}
 	ft.Results = make([]WasmField, readUint32())
 	for i := range ft.Results {
 		ft.Results[i].Type = WasmFieldType(readByte())
-		ft.Results[i].Offset = int64(readInt64())
+		ft.Results[i].Offset = readInt64()
 	}
 }
 
diff --git a/src/cmd/internal/obj/loong64/a.out.go b/src/cmd/internal/obj/loong64/a.out.go
index 100e99b1c4faa4..3cdbeb12a37395 100644
--- a/src/cmd/internal/obj/loong64/a.out.go
+++ b/src/cmd/internal/obj/loong64/a.out.go
@@ -236,7 +236,7 @@ var LOONG64DWARFRegisters = map[int16]int16{}
 func init() {
 	// f assigns dwarfregisters[from:to] = (base):(to-from+base)
 	f := func(from, to, base int16) {
-		for r := int16(from); r <= to; r++ {
+		for r := from; r <= to; r++ {
 			LOONG64DWARFRegisters[r] = (r - from) + base
 		}
 	}
diff --git a/src/cmd/internal/obj/mips/a.out.go b/src/cmd/internal/obj/mips/a.out.go
index 5439f0e4aaf1f4..b7e82c50f402ab 100644
--- a/src/cmd/internal/obj/mips/a.out.go
+++ b/src/cmd/internal/obj/mips/a.out.go
@@ -245,7 +245,7 @@ var MIPSDWARFRegisters = map[int16]int16{}
 func init() {
 	// f assigns dwarfregisters[from:to] = (base):(to-from+base)
 	f := func(from, to, base int16) {
-		for r := int16(from); r <= to; r++ {
+		for r := from; r <= to; r++ {
 			MIPSDWARFRegisters[r] = (r - from) + base
 		}
 	}
diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go
index 3299fbf4e6e1b0..4401f1bb74e0a9 100644
--- a/src/cmd/internal/obj/objfile.go
+++ b/src/cmd/internal/obj/objfile.go
@@ -166,7 +166,7 @@ func WriteObjFile(ctxt *Link, b *bio.Writer) {
 			w.Uint32(uint32(dataOff))
 			dataOff += int64(len(s.P))
 			if file := s.File(); file != nil {
-				dataOff += int64(file.Size)
+				dataOff += file.Size
 			}
 		}
 	}
diff --git a/src/cmd/internal/obj/ppc64/a.out.go b/src/cmd/internal/obj/ppc64/a.out.go
index aa7bcd30681acd..d103ebcfc35c9c 100644
--- a/src/cmd/internal/obj/ppc64/a.out.go
+++ b/src/cmd/internal/obj/ppc64/a.out.go
@@ -311,7 +311,7 @@ var PPC64DWARFRegisters = map[int16]int16{}
 func init() {
 	// f assigns dwarfregister[from:to] = (base):(to-from+base)
 	f := func(from, to, base int16) {
-		for r := int16(from); r <= to; r++ {
+		for r := from; r <= to; r++ {
 			PPC64DWARFRegisters[r] = r - from + base
 		}
 	}
diff --git a/src/cmd/internal/obj/ppc64/asm9.go b/src/cmd/internal/obj/ppc64/asm9.go
index dcd3aa59a4690a..a39c206c22da9e 100644
--- a/src/cmd/internal/obj/ppc64/asm9.go
+++ b/src/cmd/internal/obj/ppc64/asm9.go
@@ -2655,7 +2655,7 @@ func asmout(c *ctxt9, p *obj.Prog, o *Optab, out *[5]uint32) {
 	case 9: /* RLDC Ra, $sh, $mb, Rb */
 		sh := uint32(p.RestArgs[0].Addr.Offset) & 0x3F
 		mb := uint32(p.RestArgs[1].Addr.Offset) & 0x3F
-		o1 = AOP_RRR(c.opirr(p.As), uint32(p.From.Reg), uint32(p.To.Reg), (uint32(sh) & 0x1F))
+		o1 = AOP_RRR(c.opirr(p.As), uint32(p.From.Reg), uint32(p.To.Reg), (sh & 0x1F))
 		o1 |= (sh & 0x20) >> 4 // sh[5] is placed in bit 1.
 		o1 |= (mb & 0x1F) << 6 // mb[0:4] is placed in bits 6-10.
 		o1 |= (mb & 0x20)      // mb[5] is placed in bit 5
@@ -2784,7 +2784,7 @@ func asmout(c *ctxt9, p *obj.Prog, o *Optab, out *[5]uint32) {
 			if n > b || b > 63 {
 				c.ctxt.Diag("Invalid n or b for CLRLSLDI: %x %x\n%v", n, b, p)
 			}
-			o1 = AOP_MD(OP_RLDIC, uint32(p.To.Reg), uint32(r), uint32(n), uint32(b)-uint32(n))
+			o1 = AOP_MD(OP_RLDIC, uint32(p.To.Reg), r, uint32(n), uint32(b)-uint32(n))
 
 		default:
 			c.ctxt.Diag("unexpected op in rldc case\n%v", p)
@@ -2967,7 +2967,7 @@ func asmout(c *ctxt9, p *obj.Prog, o *Optab, out *[5]uint32) {
 			c.ctxt.Diag("%v is not supported", p)
 		}
 		if o.ispfx {
-			o1, o2 = pfxadd(int16(p.To.Reg), int16(r), PFX_R_ABS, d)
+			o1, o2 = pfxadd(p.To.Reg, int16(r), PFX_R_ABS, d)
 		} else if o.size == 8 {
 			o1 = LOP_IRR(OP_ORI, REGTMP, REGZERO, uint32(int32(d)))          // tmp = uint16(d)
 			o2 = AOP_RRR(c.oprrr(p.As), uint32(p.To.Reg), REGTMP, uint32(r)) // to = tmp + from
@@ -2979,7 +2979,7 @@ func asmout(c *ctxt9, p *obj.Prog, o *Optab, out *[5]uint32) {
 		} else {
 			// For backwards compatibility with GOPPC64 < 10, generate 34b constants in register.
 			o1 = LOP_IRR(OP_ADDIS, REGZERO, REGTMP, uint32(d>>32)) // tmp = sign_extend((d>>32)&0xFFFF0000)
-			o2 = loadl16(REGTMP, int64(d>>16))                     // tmp |= (d>>16)&0xFFFF
+			o2 = loadl16(REGTMP, d>>16)                            // tmp |= (d>>16)&0xFFFF
 			o3 = AOP_MD(OP_RLDICR, REGTMP, REGTMP, 16, 63-16)      // tmp <<= 16
 			o4 = loadl16(REGTMP, int64(uint16(d)))                 // tmp |= d&0xFFFF
 			o5 = AOP_RRR(c.oprrr(p.As), uint32(p.To.Reg), REGTMP, uint32(r))
@@ -3080,9 +3080,9 @@ func asmout(c *ctxt9, p *obj.Prog, o *Optab, out *[5]uint32) {
 
 		if o.ispfx {
 			if rel == nil {
-				o1, o2 = pfxadd(int16(p.To.Reg), int16(r), PFX_R_ABS, v)
+				o1, o2 = pfxadd(p.To.Reg, int16(r), PFX_R_ABS, v)
 			} else {
-				o1, o2 = pfxadd(int16(p.To.Reg), REG_R0, PFX_R_PCREL, 0)
+				o1, o2 = pfxadd(p.To.Reg, REG_R0, PFX_R_PCREL, 0)
 				rel.Type = objabi.R_ADDRPOWER_PCREL34
 			}
 		}
@@ -3519,7 +3519,7 @@ func asmout(c *ctxt9, p *obj.Prog, o *Optab, out *[5]uint32) {
 			v |= 1 << 8
 		}
 
-		o1 = AOP_RRR(OP_MTCRF, uint32(p.From.Reg), 0, 0) | uint32(v)<<12
+		o1 = AOP_RRR(OP_MTCRF, uint32(p.From.Reg), 0, 0) | v<<12
 
 	case 70: /* cmp* r,r,cr or cmp*i r,i,cr or fcmp f,f,cr or cmpeqb r,r */
 		r := uint32(p.Reg&7) << 2
diff --git a/src/cmd/internal/obj/riscv/obj.go b/src/cmd/internal/obj/riscv/obj.go
index 74699cc398534e..8c4140ec5c6452 100644
--- a/src/cmd/internal/obj/riscv/obj.go
+++ b/src/cmd/internal/obj/riscv/obj.go
@@ -905,7 +905,7 @@ func stacksplit(ctxt *obj.Link, p *obj.Prog, cursym *obj.LSym, newprog obj.ProgA
 		to_done = p
 	} else {
 		// large stack: SP-framesize < stackguard-StackSmall
-		offset := int64(framesize) - abi.StackSmall
+		offset := framesize - abi.StackSmall
 		if framesize > abi.StackBig {
 			// Such a large stack we need to protect against underflow.
 			// The runtime guarantees SP > objabi.StackBig, but
@@ -3837,7 +3837,7 @@ func instructionsForProg(p *obj.Prog) []*instruction {
 		if err != nil {
 			p.Ctxt.Diag("%v: %v", p, err)
 		}
-		ins.imm = int64(vtype)
+		ins.imm = vtype
 		if ins.as == AVSETIVLI {
 			if p.From.Type != obj.TYPE_CONST {
 				p.Ctxt.Diag("%v: expected immediate value", p)
diff --git a/src/cmd/internal/obj/s390x/a.out.go b/src/cmd/internal/obj/s390x/a.out.go
index dc715182f5cf81..caf5ec09358a03 100644
--- a/src/cmd/internal/obj/s390x/a.out.go
+++ b/src/cmd/internal/obj/s390x/a.out.go
@@ -156,7 +156,7 @@ var S390XDWARFRegisters = map[int16]int16{}
 func init() {
 	// f assigns dwarfregisters[from:to by step] = (base):((to-from)/step+base)
 	f := func(from, step, to, base int16) {
-		for r := int16(from); r <= to; r += step {
+		for r := from; r <= to; r += step {
 			S390XDWARFRegisters[r] = (r-from)/step + base
 		}
 	}
diff --git a/src/cmd/internal/obj/s390x/asmz.go b/src/cmd/internal/obj/s390x/asmz.go
index 97de5a4a0896d5..3706bb1b74e0cd 100644
--- a/src/cmd/internal/obj/s390x/asmz.go
+++ b/src/cmd/internal/obj/s390x/asmz.go
@@ -3130,7 +3130,7 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
 		case ARISBLG, ARISBLGZ:
 			opcode = op_RISBLG
 		}
-		zRIE(_f, uint32(opcode), uint32(r1), uint32(r2), 0, uint32(i3), uint32(i4), 0, uint32(i5), asm)
+		zRIE(_f, opcode, uint32(r1), uint32(r2), 0, uint32(i3), uint32(i4), 0, uint32(i5), asm)
 
 	case 15: // br/bl (reg)
 		r := p.To.Reg
@@ -3183,8 +3183,8 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
 		}
 		switch p.As {
 		case ASUB:
-			zRIL(_a, op_LGFI, uint32(regtmp(p)), uint32(v), asm)
-			zRRF(op_SLGRK, uint32(regtmp(p)), 0, uint32(p.To.Reg), uint32(r), asm)
+			zRIL(_a, op_LGFI, regtmp(p), uint32(v), asm)
+			zRRF(op_SLGRK, regtmp(p), 0, uint32(p.To.Reg), uint32(r), asm)
 		case ASUBC:
 			if r != p.To.Reg {
 				zRRE(op_LGR, uint32(p.To.Reg), uint32(r), asm)
@@ -3603,7 +3603,7 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
 				if opcode == op_MVI {
 					opcode = op_MVIY
 				} else {
-					zRXY(op_LAY, uint32(regtmp(p)), 0, uint32(r), uint32(d), asm)
+					zRXY(op_LAY, regtmp(p), 0, uint32(r), uint32(d), asm)
 					r = int16(regtmp(p))
 					d = 0
 				}
diff --git a/src/cmd/internal/obj/s390x/rotate.go b/src/cmd/internal/obj/s390x/rotate.go
index 5407c8df110999..d3cb44cabff036 100644
--- a/src/cmd/internal/obj/s390x/rotate.go
+++ b/src/cmd/internal/obj/s390x/rotate.go
@@ -67,7 +67,7 @@ func (r RotateParams) RotateLeft(amount uint8) RotateParams {
 // OutMask provides a mask representing the selected bits.
 func (r RotateParams) OutMask() uint64 {
 	// Note: z must be unsigned for bootstrap compiler
-	z := uint8(63-r.End+r.Start) & 63 // number of zero bits in mask
+	z := (63 - r.End + r.Start) & 63 // number of zero bits in mask
 	return bits.RotateLeft64(^uint64(0)< 0 {
 					s.Grow(int64(c) + int64(v))
-					fillnop(s.P[c:], int(v))
+					fillnop(s.P[c:], v)
 				}
 				p.Pc = int64(c)
 				c += int32(v)
@@ -3277,7 +3277,7 @@ func (ab *AsmBuf) Put(b []byte) {
 // Literal Z cases usually have "Zlit" in their name (Zlit, Zlitr_m, Zlitm_r).
 func (ab *AsmBuf) PutOpBytesLit(offset int, op *opBytes) {
 	for int(op[offset]) != 0 {
-		ab.Put1(byte(op[offset]))
+		ab.Put1(op[offset])
 		offset++
 	}
 }
diff --git a/src/cmd/internal/obj/x86/asm_test.go b/src/cmd/internal/obj/x86/asm_test.go
index 458a91258a35b0..11655829838f0c 100644
--- a/src/cmd/internal/obj/x86/asm_test.go
+++ b/src/cmd/internal/obj/x86/asm_test.go
@@ -286,7 +286,7 @@ func TestRegIndex(t *testing.T) {
 			have := regIndex(int16(reg))
 			want := index
 			if have != want {
-				regName := rconv(int(reg))
+				regName := rconv(reg)
 				t.Errorf("regIndex(%s):\nhave: %d\nwant: %d",
 					regName, have, want)
 			}
diff --git a/src/cmd/internal/objfile/goobj.go b/src/cmd/internal/objfile/goobj.go
index c428e29c9b19a4..7d564a2661d951 100644
--- a/src/cmd/internal/objfile/goobj.go
+++ b/src/cmd/internal/objfile/goobj.go
@@ -240,7 +240,7 @@ func (f *goobjFile) PCToLine(pc uint64) (string, int, *gosym.Func) {
 			// We don't need the data for non-hashed symbols, yet.
 			panic("not supported")
 		}
-		i := uint32(s.SymIdx + uint32(r.NSym()+r.NHashed64def()))
+		i := s.SymIdx + uint32(r.NSym()+r.NHashed64def())
 		return r.BytesAt(r.DataOff(i), r.DataSize(i))
 	}
 
@@ -325,7 +325,7 @@ func readvarint(p *[]byte) uint32 {
 // We treat the whole object file as the text section.
 func (f *goobjFile) text() (textStart uint64, text []byte, err error) {
 	text = make([]byte, f.goobj.Size)
-	_, err = f.f.ReadAt(text, int64(f.goobj.Offset))
+	_, err = f.f.ReadAt(text, f.goobj.Offset)
 	return
 }
 
diff --git a/src/cmd/internal/objfile/xcoff.go b/src/cmd/internal/objfile/xcoff.go
index d6df4db8f01d06..24f42760c9dd60 100644
--- a/src/cmd/internal/objfile/xcoff.go
+++ b/src/cmd/internal/objfile/xcoff.go
@@ -44,7 +44,7 @@ func (f *xcoffFile) symbols() ([]Sym, error) {
 		case N_DEBUG:
 			sym.Code = '?'
 		default:
-			if s.SectionNumber < 0 || len(f.xcoff.Sections) < int(s.SectionNumber) {
+			if s.SectionNumber < 0 || len(f.xcoff.Sections) < s.SectionNumber {
 				return nil, fmt.Errorf("invalid section number in symbol table")
 			}
 			sect := f.xcoff.Sections[s.SectionNumber-1]
@@ -116,7 +116,7 @@ func findXCOFFSymbol(f *xcoff.File, name string) (*xcoff.Symbol, error) {
 		if s.SectionNumber <= 0 {
 			return nil, fmt.Errorf("symbol %s: invalid section number %d", name, s.SectionNumber)
 		}
-		if len(f.Sections) < int(s.SectionNumber) {
+		if len(f.Sections) < s.SectionNumber {
 			return nil, fmt.Errorf("symbol %s: section number %d is larger than max %d", name, s.SectionNumber, len(f.Sections))
 		}
 		return s, nil
diff --git a/src/cmd/link/internal/amd64/asm.go b/src/cmd/link/internal/amd64/asm.go
index 5424de800cac9f..d27342f23fb5fb 100644
--- a/src/cmd/link/internal/amd64/asm.go
+++ b/src/cmd/link/internal/amd64/asm.go
@@ -407,7 +407,7 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
 			} else {
 				ldr.Errorf(s, "unexpected relocation for dynamic symbol %s", ldr.SymName(targ))
 			}
-			rela.AddAddrPlus(target.Arch, targ, int64(r.Add()))
+			rela.AddAddrPlus(target.Arch, targ, r.Add())
 			// Not mark r done here. So we still apply it statically,
 			// so in the file content we'll also have the right offset
 			// to the relocation target. So it can be examined statically
diff --git a/src/cmd/link/internal/arm/asm.go b/src/cmd/link/internal/arm/asm.go
index a113196d10c10d..248ec648bcc81f 100644
--- a/src/cmd/link/internal/arm/asm.go
+++ b/src/cmd/link/internal/arm/asm.go
@@ -400,7 +400,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
 			for i := 0; ; i++ {
 				oName := ldr.SymName(rs)
 				name := oName + fmt.Sprintf("%+d-tramp%d", offset, i)
-				tramp = ldr.LookupOrCreateSym(name, int(ldr.SymVersion(rs)))
+				tramp = ldr.LookupOrCreateSym(name, ldr.SymVersion(rs))
 				ldr.SetAttrReachable(tramp, true)
 				if ldr.SymType(tramp) == sym.SDYNIMPORT {
 					// don't reuse trampoline defined in other module
diff --git a/src/cmd/link/internal/arm64/asm.go b/src/cmd/link/internal/arm64/asm.go
index 8d8ea8ac542c50..1f4282adecc747 100644
--- a/src/cmd/link/internal/arm64/asm.go
+++ b/src/cmd/link/internal/arm64/asm.go
@@ -457,7 +457,7 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
 			} else {
 				ldr.Errorf(s, "unexpected relocation for dynamic symbol %s", ldr.SymName(targ))
 			}
-			rela.AddAddrPlus(target.Arch, targ, int64(r.Add()))
+			rela.AddAddrPlus(target.Arch, targ, r.Add())
 			// Not mark r done here. So we still apply it statically,
 			// so in the file content we'll also have the right offset
 			// to the relocation target. So it can be examined statically
@@ -876,7 +876,7 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
 				if r.Siz() == 8 {
 					val = r.Add()
 				} else if target.IsBigEndian() {
-					val = int64(uint32(val)) | int64(r.Add())<<32
+					val = int64(uint32(val)) | r.Add()<<32
 				} else {
 					val = val>>32<<32 | int64(uint32(r.Add()))
 				}
@@ -972,13 +972,13 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
 
 			// R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21
 			// turn ADRP to MOVZ
-			o0 = 0xd2a00000 | uint32(o0&0x1f) | (uint32((v>>16)&0xffff) << 5)
+			o0 = 0xd2a00000 | o0&0x1f | (uint32((v>>16)&0xffff) << 5)
 			// R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC
 			// turn LD64 to MOVK
 			if v&3 != 0 {
 				ldr.Errorf(s, "invalid address: %x for relocation type: R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC", v)
 			}
-			o1 = 0xf2800000 | uint32(o1&0x1f) | (uint32(v&0xffff) << 5)
+			o1 = 0xf2800000 | o1&0x1f | (uint32(v&0xffff) << 5)
 
 			// when laid out, the instruction order must always be o0, o1.
 			if target.IsBigEndian() {
@@ -1372,7 +1372,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
 			for i := 0; ; i++ {
 				oName := ldr.SymName(rs)
 				name := oName + fmt.Sprintf("%+x-tramp%d", r.Add(), i)
-				tramp = ldr.LookupOrCreateSym(name, int(ldr.SymVersion(rs)))
+				tramp = ldr.LookupOrCreateSym(name, ldr.SymVersion(rs))
 				ldr.SetAttrReachable(tramp, true)
 				if ldr.SymType(tramp) == sym.SDYNIMPORT {
 					// don't reuse trampoline defined in other module
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index a49cae0d9527ca..dfb1d7bafbd51d 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -427,7 +427,7 @@ func (st *relocSymState) relocsym(s loader.Sym, P []byte) {
 			}
 		case objabi.R_DWTXTADDR_U1, objabi.R_DWTXTADDR_U2, objabi.R_DWTXTADDR_U3, objabi.R_DWTXTADDR_U4:
 			unit := ldr.SymUnit(rs)
-			if idx, ok := unit.Addrs[sym.LoaderSym(rs)]; ok {
+			if idx, ok := unit.Addrs[rs]; ok {
 				o = int64(idx)
 			} else {
 				st.err.Errorf(s, "missing .debug_addr index relocation target %s", ldr.SymName(rs))
@@ -512,7 +512,7 @@ func (st *relocSymState) relocsym(s loader.Sym, P []byte) {
 		case objabi.R_ADDRCUOFF:
 			// debug_range and debug_loc elements use this relocation type to get an
 			// offset from the start of the compile unit.
-			o = ldr.SymValue(rs) + r.Add() - ldr.SymValue(loader.Sym(ldr.SymUnit(rs).Textp[0]))
+			o = ldr.SymValue(rs) + r.Add() - ldr.SymValue(ldr.SymUnit(rs).Textp[0])
 
 		// r.Sym() can be 0 when CALL $(constant) is transformed from absolute PC to relative PC call.
 		case objabi.R_GOTPCREL:
@@ -560,7 +560,7 @@ func (st *relocSymState) relocsym(s loader.Sym, P []byte) {
 							if rst != sym.SHOSTOBJ {
 								o += int64(uint64(ldr.SymValue(rs)) - ldr.SymSect(rs).Vaddr)
 							}
-							o -= int64(off) // relative to section offset, not symbol
+							o -= off // relative to section offset, not symbol
 						}
 					} else {
 						o += int64(siz)
@@ -698,7 +698,7 @@ func extreloc(ctxt *Link, ldr *loader.Loader, s loader.Sym, r loader.Reloc) (loa
 			return rr, false
 		}
 		rs := r.Sym()
-		rr.Xsym = loader.Sym(ldr.SymSect(rs).Sym)
+		rr.Xsym = ldr.SymSect(rs).Sym
 		rr.Xadd = r.Add() + ldr.SymValue(rs) - int64(ldr.SymSect(rs).Vaddr)
 
 	// r.Sym() can be 0 when CALL $(constant) is transformed from absolute PC to relative PC call.
@@ -2268,7 +2268,7 @@ func (state *dodataState) allocateDwarfSections(ctxt *Link) {
 		s := dwarfp[i].secSym()
 		sect := state.allocateNamedDataSection(&Segdwarf, ldr.SymName(s), []sym.SymKind{}, 04)
 		ldr.SetSymSect(s, sect)
-		sect.Sym = sym.LoaderSym(s)
+		sect.Sym = s
 		curType := ldr.SymType(s)
 		state.setSymType(s, sym.SRODATA)
 		ldr.SetSymValue(s, int64(uint64(state.datsize)-sect.Vaddr))
diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index 0003938ef2e036..222e712edeb608 100644
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -1011,7 +1011,7 @@ func (d *dwctxt) addDwarfAddrRef(sb *loader.SymbolBuilder, t loader.Sym) {
 func (d *dwctxt) calcCompUnitRanges() {
 	var prevUnit *sym.CompilationUnit
 	for _, s := range d.linkctxt.Textp {
-		sym := loader.Sym(s)
+		sym := s
 
 		fi := d.ldr.FuncInfo(sym)
 		if !fi.Valid() {
@@ -1033,7 +1033,7 @@ func (d *dwctxt) calcCompUnitRanges() {
 		// only create boundaries between symbols from
 		// different units.
 		sval := d.ldr.SymValue(sym)
-		u0val := d.ldr.SymValue(loader.Sym(unit.Textp[0]))
+		u0val := d.ldr.SymValue(unit.Textp[0])
 		if prevUnit != unit {
 			unit.PCs = append(unit.PCs, dwarf.Range{Start: sval - u0val})
 			prevUnit = unit
@@ -1339,7 +1339,7 @@ func (d *dwctxt) writelines(unit *sym.CompilationUnit, lineProlog loader.Sym) []
 
 	// Output the state machine for each function remaining.
 	for _, s := range unit.Textp {
-		fnSym := loader.Sym(s)
+		fnSym := s
 		_, _, _, lines := d.ldr.GetFuncDwarfAuxSyms(fnSym)
 
 		// Chain the line symbol onto the list.
@@ -1399,7 +1399,7 @@ func (d *dwctxt) writepcranges(unit *sym.CompilationUnit, base loader.Sym, pcs [
 	// Collect up the ranges for functions in the unit.
 	rsize := uint64(rsu.Size())
 	for _, ls := range unit.RangeSyms {
-		s := loader.Sym(ls)
+		s := ls
 		syms = append(syms, s)
 		rsize += uint64(d.ldr.SymSize(s))
 	}
@@ -1501,7 +1501,7 @@ func (d *dwctxt) writeframes(fs loader.Sym) dwarfSecInfo {
 	var deltaBuf []byte
 	pcsp := obj.NewPCIter(uint32(d.arch.MinLC))
 	for _, s := range d.linkctxt.Textp {
-		fn := loader.Sym(s)
+		fn := s
 		fi := d.ldr.FuncInfo(fn)
 		if !fi.Valid() {
 			continue
@@ -1646,7 +1646,7 @@ func (d *dwctxt) writeUnitInfo(u *sym.CompilationUnit, abbrevsym loader.Sym, add
 	cu = append(cu, u.AbsFnDIEs...)
 	cu = append(cu, u.FuncDIEs...)
 	if u.Consts != 0 {
-		cu = append(cu, loader.Sym(u.Consts))
+		cu = append(cu, u.Consts)
 	}
 	cu = append(cu, u.VarDIEs...)
 	var cusize int64
@@ -1772,7 +1772,7 @@ func (d *dwctxt) assignDebugAddrSlot(unit *sym.CompilationUnit, fnsym loader.Sym
 	if unit.Addrs == nil {
 		unit.Addrs = make(map[sym.LoaderSym]uint32)
 	}
-	if _, ok := unit.Addrs[sym.LoaderSym(rsym)]; ok {
+	if _, ok := unit.Addrs[rsym]; ok {
 		// already present, no work needed
 	} else {
 		sl := len(unit.Addrs)
@@ -1781,7 +1781,7 @@ func (d *dwctxt) assignDebugAddrSlot(unit *sym.CompilationUnit, fnsym loader.Sym
 		if sl > lim {
 			log.Fatalf("internal error: %s relocation overflow on infosym for %s", rt.String(), d.ldr.SymName(fnsym))
 		}
-		unit.Addrs[sym.LoaderSym(rsym)] = uint32(sl)
+		unit.Addrs[rsym] = uint32(sl)
 		sb.AddAddrPlus(d.arch, rsym, 0)
 		data := sb.Data()
 		if d.arch.PtrSize == 4 {
@@ -1805,11 +1805,11 @@ func (d *dwctxt) dwarfVisitFunction(fnSym loader.Sym, unit *sym.CompilationUnit)
 	}
 	d.ldr.SetAttrNotInSymbolTable(infosym, true)
 	d.ldr.SetAttrReachable(infosym, true)
-	unit.FuncDIEs = append(unit.FuncDIEs, sym.LoaderSym(infosym))
+	unit.FuncDIEs = append(unit.FuncDIEs, infosym)
 	if rangesym != 0 {
 		d.ldr.SetAttrNotInSymbolTable(rangesym, true)
 		d.ldr.SetAttrReachable(rangesym, true)
-		unit.RangeSyms = append(unit.RangeSyms, sym.LoaderSym(rangesym))
+		unit.RangeSyms = append(unit.RangeSyms, rangesym)
 	}
 
 	// Walk the relocations of the subprogram DIE symbol to discover
@@ -1836,7 +1836,7 @@ func (d *dwctxt) dwarfVisitFunction(fnSym loader.Sym, unit *sym.CompilationUnit)
 			if !d.ldr.AttrOnList(rsym) {
 				// abstract function
 				d.ldr.SetAttrOnList(rsym, true)
-				unit.AbsFnDIEs = append(unit.AbsFnDIEs, sym.LoaderSym(rsym))
+				unit.AbsFnDIEs = append(unit.AbsFnDIEs, rsym)
 				d.importInfoSymbol(rsym)
 			}
 			continue
@@ -1942,7 +1942,7 @@ func dwarfGenerateDebugInfo(ctxt *Link) {
 		for _, unit := range lib.Units {
 			// We drop the constants into the first CU.
 			if consts != 0 {
-				unit.Consts = sym.LoaderSym(consts)
+				unit.Consts = consts
 				d.importInfoSymbol(consts)
 				consts = 0
 			}
@@ -2008,7 +2008,7 @@ func dwarfGenerateDebugInfo(ctxt *Link) {
 			// abstract functions, visit range symbols. Note that
 			// Textp has been dead-code-eliminated already.
 			for _, s := range unit.Textp {
-				d.dwarfVisitFunction(loader.Sym(s), unit)
+				d.dwarfVisitFunction(s, unit)
 			}
 		}
 	}
@@ -2073,7 +2073,7 @@ func dwarfGenerateDebugInfo(ctxt *Link) {
 		if varDIE != 0 {
 			unit := d.ldr.SymUnit(idx)
 			d.defgotype(gt)
-			unit.VarDIEs = append(unit.VarDIEs, sym.LoaderSym(varDIE))
+			unit.VarDIEs = append(unit.VarDIEs, varDIE)
 		}
 	}
 
@@ -2125,7 +2125,7 @@ type dwUnitSyms struct {
 func (d *dwctxt) dwUnitPortion(u *sym.CompilationUnit, abbrevsym loader.Sym, us *dwUnitSyms) {
 	if u.DWInfo.Abbrev != dwarf.DW_ABRV_COMPUNIT_TEXTLESS {
 		us.linesyms = d.writelines(u, us.lineProlog)
-		base := loader.Sym(u.Textp[0])
+		base := u.Textp[0]
 		if buildcfg.Experiment.Dwarf5 {
 			d.writedebugaddr(u, us.addrsym)
 		}
@@ -2145,7 +2145,7 @@ func (d *dwctxt) writedebugaddr(unit *sym.CompilationUnit, debugaddr loader.Sym)
 
 	var dsyms []loader.Sym
 	for _, s := range unit.Textp {
-		fnSym := loader.Sym(s)
+		fnSym := s
 		// NB: this looks at SDWARFFCN; it will need to also look
 		// at range and loc when they get there.
 		infosym, locsym, rangessym, _ := d.ldr.GetFuncDwarfAuxSyms(fnSym)
@@ -2305,8 +2305,8 @@ func (d *dwctxt) dwarfGenerateDebugSyms() {
 		len += uint64(d.ldr.SymSize(hdrsym))
 		su := d.ldr.MakeSymbolUpdater(hdrsym)
 		if isDwarf64(d.linkctxt) {
-			len -= 12                          // sub size of length field
-			su.SetUint(d.arch, 4, uint64(len)) // 4 because of 0XFFFFFFFF
+			len -= 12                  // sub size of length field
+			su.SetUint(d.arch, 4, len) // 4 because of 0XFFFFFFFF
 		} else {
 			len -= 4 // subtract size of length field
 			su.SetUint32(d.arch, 0, uint32(len))
@@ -2377,7 +2377,7 @@ func (d *dwctxt) dwarfGenerateDebugSyms() {
 func (d *dwctxt) collectUnitLocs(u *sym.CompilationUnit) []loader.Sym {
 	syms := []loader.Sym{}
 	for _, fn := range u.FuncDIEs {
-		relocs := d.ldr.Relocs(loader.Sym(fn))
+		relocs := d.ldr.Relocs(fn)
 		for i := 0; i < relocs.Count(); i++ {
 			reloc := relocs.At(i)
 			if reloc.Type() != objabi.R_DWARFSECREF {
@@ -2510,7 +2510,7 @@ func dwarfcompress(ctxt *Link) {
 			ldr.SetSymValue(s, int64(pos))
 			sect := ldr.SymSect(s)
 			if sect != prevSect {
-				sect.Vaddr = uint64(pos)
+				sect.Vaddr = pos
 				prevSect = sect
 			}
 			if ldr.SubSym(s) != 0 {
diff --git a/src/cmd/link/internal/ld/elf.go b/src/cmd/link/internal/ld/elf.go
index 6ff1d943833783..ed215d7fe50128 100644
--- a/src/cmd/link/internal/ld/elf.go
+++ b/src/cmd/link/internal/ld/elf.go
@@ -343,8 +343,8 @@ func elf32phdr(out *OutBuf, e *ElfPhdr) {
 
 func elf64shdr(out *OutBuf, e *ElfShdr) {
 	out.Write32(e.Name)
-	out.Write32(uint32(e.Type))
-	out.Write64(uint64(e.Flags))
+	out.Write32(e.Type)
+	out.Write64(e.Flags)
 	out.Write64(e.Addr)
 	out.Write64(e.Off)
 	out.Write64(e.Size)
@@ -356,7 +356,7 @@ func elf64shdr(out *OutBuf, e *ElfShdr) {
 
 func elf32shdr(out *OutBuf, e *ElfShdr) {
 	out.Write32(e.Name)
-	out.Write32(uint32(e.Type))
+	out.Write32(e.Type)
 	out.Write32(uint32(e.Flags))
 	out.Write32(uint32(e.Addr))
 	out.Write32(uint32(e.Off))
@@ -442,9 +442,9 @@ func getElfEhdr() *ElfEhdr {
 
 func elf64writehdr(out *OutBuf) uint32 {
 	out.Write(ehdr.Ident[:])
-	out.Write16(uint16(ehdr.Type))
-	out.Write16(uint16(ehdr.Machine))
-	out.Write32(uint32(ehdr.Version))
+	out.Write16(ehdr.Type)
+	out.Write16(ehdr.Machine)
+	out.Write32(ehdr.Version)
 	out.Write64(ehdr.Entry)
 	out.Write64(ehdr.Phoff)
 	out.Write64(ehdr.Shoff)
@@ -460,9 +460,9 @@ func elf64writehdr(out *OutBuf) uint32 {
 
 func elf32writehdr(out *OutBuf) uint32 {
 	out.Write(ehdr.Ident[:])
-	out.Write16(uint16(ehdr.Type))
-	out.Write16(uint16(ehdr.Machine))
-	out.Write32(uint32(ehdr.Version))
+	out.Write16(ehdr.Type)
+	out.Write16(ehdr.Machine)
+	out.Write32(ehdr.Version)
 	out.Write32(uint32(ehdr.Entry))
 	out.Write32(uint32(ehdr.Phoff))
 	out.Write32(uint32(ehdr.Shoff))
@@ -1379,7 +1379,7 @@ func elfEmitReloc(ctxt *Link) {
 	for i := 0; i < len(Segdwarf.Sections); i++ {
 		sect := Segdwarf.Sections[i]
 		si := dwarfp[i]
-		if si.secSym() != loader.Sym(sect.Sym) ||
+		if si.secSym() != sect.Sym ||
 			ctxt.loader.SymSect(si.secSym()) != sect {
 			panic("inconsistency between dwarfp and Segdwarf")
 		}
@@ -1426,7 +1426,7 @@ func (ctxt *Link) doelf() {
 
 	shstrtabAddstring := func(s string) {
 		off := addshstr(s)
-		elfsetstring(ctxt, 0, s, int(off))
+		elfsetstring(ctxt, 0, s, off)
 	}
 
 	shstrtabAddstring("")
diff --git a/src/cmd/link/internal/ld/macho.go b/src/cmd/link/internal/ld/macho.go
index c26263466616f5..8e059f299ffa73 100644
--- a/src/cmd/link/internal/ld/macho.go
+++ b/src/cmd/link/internal/ld/macho.go
@@ -1254,7 +1254,7 @@ func machoEmitReloc(ctxt *Link) {
 	for i := 0; i < len(Segdwarf.Sections); i++ {
 		sect := Segdwarf.Sections[i]
 		si := dwarfp[i]
-		if si.secSym() != loader.Sym(sect.Sym) ||
+		if si.secSym() != sect.Sym ||
 			ctxt.loader.SymSect(si.secSym()) != sect {
 			panic("inconsistency between dwarfp and Segdwarf")
 		}
@@ -1535,11 +1535,11 @@ func machoCodeSign(ctxt *Link, fname string) error {
 		// Uodate the __LINKEDIT segment.
 		segSz := sigOff + sz - int64(linkeditSeg.Offset)
 		mf.ByteOrder.PutUint64(tmp[:8], uint64(segSz))
-		_, err = f.WriteAt(tmp[:8], int64(linkeditOff)+int64(unsafe.Offsetof(macho.Segment64{}.Memsz)))
+		_, err = f.WriteAt(tmp[:8], linkeditOff+int64(unsafe.Offsetof(macho.Segment64{}.Memsz)))
 		if err != nil {
 			return err
 		}
-		_, err = f.WriteAt(tmp[:8], int64(linkeditOff)+int64(unsafe.Offsetof(macho.Segment64{}.Filesz)))
+		_, err = f.WriteAt(tmp[:8], linkeditOff+int64(unsafe.Offsetof(macho.Segment64{}.Filesz)))
 		if err != nil {
 			return err
 		}
diff --git a/src/cmd/link/internal/ld/pcln.go b/src/cmd/link/internal/ld/pcln.go
index 9532b33a9bc1cc..2b3687c37e4a6a 100644
--- a/src/cmd/link/internal/ld/pcln.go
+++ b/src/cmd/link/internal/ld/pcln.go
@@ -216,7 +216,7 @@ func genInlTreeSym(ctxt *Link, cu *sym.CompilationUnit, fi loader.FuncInfo, arch
 		const size = 16
 		inlTreeSym.SetUint8(arch, int64(i*size+0), uint8(funcID))
 		// Bytes 1-3 are unused.
-		inlTreeSym.SetUint32(arch, int64(i*size+4), uint32(nameOff))
+		inlTreeSym.SetUint32(arch, int64(i*size+4), nameOff)
 		inlTreeSym.SetUint32(arch, int64(i*size+8), uint32(call.ParentPC))
 		inlTreeSym.SetUint32(arch, int64(i*size+12), uint32(startLine))
 	}
@@ -683,14 +683,14 @@ func writeFuncs(ctxt *Link, sb *loader.SymbolBuilder, funcs []loader.Sym, inlSym
 		off := int64(startLocations[i])
 		// entryOff uint32 (offset of func entry PC from textStart)
 		entryOff := textOff(ctxt, s, textStart)
-		off = sb.SetUint32(ctxt.Arch, off, uint32(entryOff))
+		off = sb.SetUint32(ctxt.Arch, off, entryOff)
 
 		// nameOff int32
 		nameOff, ok := nameOffsets[s]
 		if !ok {
 			panic("couldn't find function name offset")
 		}
-		off = sb.SetUint32(ctxt.Arch, off, uint32(nameOff))
+		off = sb.SetUint32(ctxt.Arch, off, nameOff)
 
 		// args int32
 		// TODO: Move into funcinfo.
@@ -712,7 +712,7 @@ func writeFuncs(ctxt *Link, sb *loader.SymbolBuilder, funcs []loader.Sym, inlSym
 		} else {
 			off += 12
 		}
-		off = sb.SetUint32(ctxt.Arch, off, uint32(numPCData(ldr, s, fi)))
+		off = sb.SetUint32(ctxt.Arch, off, numPCData(ldr, s, fi))
 
 		// Store the offset to compilation unit's file table.
 		cuIdx := ^uint32(0)
diff --git a/src/cmd/link/internal/ld/pe.go b/src/cmd/link/internal/ld/pe.go
index e0186f46b035d9..f5b7580fda3307 100644
--- a/src/cmd/link/internal/ld/pe.go
+++ b/src/cmd/link/internal/ld/pe.go
@@ -653,7 +653,7 @@ dwarfLoop:
 	for i := 0; i < len(Segdwarf.Sections); i++ {
 		sect := Segdwarf.Sections[i]
 		si := dwarfp[i]
-		if si.secSym() != loader.Sym(sect.Sym) ||
+		if si.secSym() != sect.Sym ||
 			ldr.SymSect(si.secSym()) != sect {
 			panic("inconsistency between dwarfp and Segdwarf")
 		}
@@ -1506,7 +1506,7 @@ func (rt *peBaseRelocTable) addentry(ldr *loader.Loader, s loader.Sym, r *loader
 	const pageSize = 0x1000
 	const pageMask = pageSize - 1
 
-	addr := ldr.SymValue(s) + int64(r.Off()) - int64(PEBASE)
+	addr := ldr.SymValue(s) + int64(r.Off()) - PEBASE
 	page := uint32(addr &^ pageMask)
 	off := uint32(addr & pageMask)
 
diff --git a/src/cmd/link/internal/ld/xcoff.go b/src/cmd/link/internal/ld/xcoff.go
index da728e25455618..fdc16ac48f9d2b 100644
--- a/src/cmd/link/internal/ld/xcoff.go
+++ b/src/cmd/link/internal/ld/xcoff.go
@@ -677,7 +677,7 @@ func (f *xcoffFile) writeSymbolNewFile(ctxt *Link, name string, firstEntry uint6
 			dwsize = getDwsectCUSize(sect.Name, name)
 			// .debug_abbrev is common to all packages and not found with the previous function
 			if sect.Name == ".debug_abbrev" {
-				dwsize = uint64(ldr.SymSize(loader.Sym(sect.Sym)))
+				dwsize = uint64(ldr.SymSize(sect.Sym))
 
 			}
 		} else {
@@ -699,7 +699,7 @@ func (f *xcoffFile) writeSymbolNewFile(ctxt *Link, name string, firstEntry uint6
 			// Dwarf relocations need the symbol number of .dw* symbols.
 			// It doesn't need to know it for each package, one is enough.
 			// currSymSrcFile.csectAux == nil means first package.
-			ldr.SetSymDynid(loader.Sym(sect.Sym), int32(f.symbolCount))
+			ldr.SetSymDynid(sect.Sym, int32(f.symbolCount))
 
 			if sect.Name == ".debug_frame" && ctxt.LinkMode != LinkExternal {
 				// CIE size must be added to the first package.
@@ -865,7 +865,7 @@ func (f *xcoffFile) writeSymbolFunc(ctxt *Link, x loader.Sym) []xcoffSym {
 		Xsmtyp:    XTY_LD, // label definition (based on C)
 		Xauxtype:  _AUX_CSECT,
 	}
-	a4.Xsmtyp |= uint8(xcoffAlign(ldr, x, TextSym) << 3)
+	a4.Xsmtyp |= xcoffAlign(ldr, x, TextSym) << 3
 
 	syms = append(syms, a4)
 	return syms
@@ -915,7 +915,7 @@ func putaixsym(ctxt *Link, x loader.Sym, t SymbolType) {
 				Xsmclas:   XMC_PR,
 				Xsmtyp:    XTY_SD,
 			}
-			a4.Xsmtyp |= uint8(xcoffAlign(ldr, x, TextSym) << 3)
+			a4.Xsmtyp |= xcoffAlign(ldr, x, TextSym) << 3
 			syms = append(syms, a4)
 		}
 
@@ -976,7 +976,7 @@ func putaixsym(ctxt *Link, x loader.Sym, t SymbolType) {
 			a4.Xsmtyp |= XTY_CM
 		}
 
-		a4.Xsmtyp |= uint8(xcoffAlign(ldr, x, t) << 3)
+		a4.Xsmtyp |= xcoffAlign(ldr, x, t) << 3
 
 		syms = append(syms, a4)
 
@@ -1375,7 +1375,7 @@ func (f *xcoffFile) writeLdrScn(ctxt *Link, globalOff uint64) {
 	/* Symbol table */
 	for _, s := range f.loaderSymbols {
 		lds := &XcoffLdSym64{
-			Loffset: uint32(stlen + 2),
+			Loffset: stlen + 2,
 			Lsmtype: s.smtype,
 			Lsmclas: s.smclas,
 		}
@@ -1580,7 +1580,7 @@ func xcoffwrite(ctxt *Link) {
 func asmbXcoff(ctxt *Link) {
 	ctxt.Out.SeekSet(0)
 	fileoff := int64(Segdwarf.Fileoff + Segdwarf.Filelen)
-	fileoff = int64(Rnd(int64(fileoff), *FlagRound))
+	fileoff = Rnd(fileoff, *FlagRound)
 
 	xfile.sectNameToScnum = make(map[string]int16)
 
@@ -1693,7 +1693,7 @@ func (f *xcoffFile) emitRelocations(ctxt *Link, fileoff int64) {
 			if !ldr.AttrReachable(s) {
 				continue
 			}
-			if ldr.SymValue(s) >= int64(eaddr) {
+			if ldr.SymValue(s) >= eaddr {
 				break
 			}
 
@@ -1755,7 +1755,7 @@ dwarfLoop:
 	for i := 0; i < len(Segdwarf.Sections); i++ {
 		sect := Segdwarf.Sections[i]
 		si := dwarfp[i]
-		if si.secSym() != loader.Sym(sect.Sym) ||
+		if si.secSym() != sect.Sym ||
 			ldr.SymSect(si.secSym()) != sect {
 			panic("inconsistency between dwarfp and Segdwarf")
 		}
diff --git a/src/cmd/link/internal/loadelf/ldelf.go b/src/cmd/link/internal/loadelf/ldelf.go
index bb0c22da7ef0ac..9434704be4dc99 100644
--- a/src/cmd/link/internal/loadelf/ldelf.go
+++ b/src/cmd/link/internal/loadelf/ldelf.go
@@ -785,12 +785,12 @@ func Load(l *loader.Loader, arch *sys.Arch, localSymVersion int, f *bio.Reader,
 				rSym = 0
 			} else {
 				var elfsym ElfSym
-				if err := readelfsym(l, arch, elfobj, int(symIdx), &elfsym, 0, 0); err != nil {
+				if err := readelfsym(l, arch, elfobj, symIdx, &elfsym, 0, 0); err != nil {
 					return errorf("malformed elf file: %v", err)
 				}
 				elfsym.sym = symbols[symIdx]
 				if elfsym.sym == 0 {
-					return errorf("malformed elf file: %s#%d: reloc of invalid sym #%d %s shndx=%d type=%d", l.SymName(sect.sym), j, int(symIdx), elfsym.name, elfsym.shndx, elfsym.type_)
+					return errorf("malformed elf file: %s#%d: reloc of invalid sym #%d %s shndx=%d type=%d", l.SymName(sect.sym), j, symIdx, elfsym.name, elfsym.shndx, elfsym.type_)
 				}
 
 				rSym = elfsym.sym
@@ -854,7 +854,7 @@ func elfmap(elfobj *ElfObj, sect *ElfSect) (err error) {
 	}
 
 	elfobj.f.MustSeek(int64(uint64(elfobj.base)+sect.off), 0)
-	sect.base, sect.readOnlyMem, err = elfobj.f.Slice(uint64(sect.size))
+	sect.base, sect.readOnlyMem, err = elfobj.f.Slice(sect.size)
 	if err != nil {
 		return fmt.Errorf("short read: %v", err)
 	}
diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go
index 0ed20d1becbb03..cef17fae781798 100644
--- a/src/cmd/link/internal/loader/loader.go
+++ b/src/cmd/link/internal/loader/loader.go
@@ -806,7 +806,7 @@ func (l *Loader) SymVersion(i Sym) int {
 		return pp.ver
 	}
 	r, li := l.toLocal(i)
-	return int(abiToVer(r.Sym(li).ABI(), r.version))
+	return abiToVer(r.Sym(li).ABI(), r.version)
 }
 
 func (l *Loader) IsFileLocal(i Sym) bool {
@@ -2748,15 +2748,15 @@ func (l *Loader) AssignTextSymbolOrder(libs []*sym.Library, intlibs []bool, exts
 				// We still need to record its presence in the current
 				// package, as the trampoline pass expects packages
 				// are laid out in dependency order.
-				lib.DupTextSyms = append(lib.DupTextSyms, sym.LoaderSym(gi))
+				lib.DupTextSyms = append(lib.DupTextSyms, gi)
 				continue // symbol in different object
 			}
 			if dupok {
-				lib.DupTextSyms = append(lib.DupTextSyms, sym.LoaderSym(gi))
+				lib.DupTextSyms = append(lib.DupTextSyms, gi)
 				continue
 			}
 
-			lib.Textp = append(lib.Textp, sym.LoaderSym(gi))
+			lib.Textp = append(lib.Textp, gi)
 		}
 	}
 
@@ -2769,7 +2769,7 @@ func (l *Loader) AssignTextSymbolOrder(libs []*sym.Library, intlibs []bool, exts
 			lists := [2][]sym.LoaderSym{lib.Textp, lib.DupTextSyms}
 			for i, list := range lists {
 				for _, s := range list {
-					sym := Sym(s)
+					sym := s
 					if !assignedToUnit.Has(sym) {
 						textp = append(textp, sym)
 						unit := l.SymUnit(sym)
diff --git a/src/cmd/link/internal/loong64/asm.go b/src/cmd/link/internal/loong64/asm.go
index 6adafd38fc5466..e7f3fd1d9817ad 100644
--- a/src/cmd/link/internal/loong64/asm.go
+++ b/src/cmd/link/internal/loong64/asm.go
@@ -273,7 +273,7 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
 			} else {
 				ldr.Errorf(s, "unexpected relocation for dynamic symbol %s", ldr.SymName(targ))
 			}
-			rela.AddAddrPlus(target.Arch, targ, int64(r.Add()))
+			rela.AddAddrPlus(target.Arch, targ, r.Add())
 			return true
 		}
 
@@ -496,30 +496,30 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
 		pc := ldr.SymValue(s) + int64(r.Off())
 		t := calculatePCAlignedReloc(r.Type(), ldr.SymAddr(rs)+r.Add(), pc)
 		if r.Type() == objabi.R_LOONG64_ADDR_LO {
-			return int64(val&0xffc003ff | (t << 10)), noExtReloc, isOk
+			return val&0xffc003ff | (t << 10), noExtReloc, isOk
 		}
-		return int64(val&0xfe00001f | (t << 5)), noExtReloc, isOk
+		return val&0xfe00001f | (t << 5), noExtReloc, isOk
 	case objabi.R_LOONG64_TLS_LE_HI,
 		objabi.R_LOONG64_TLS_LE_LO:
 		t := ldr.SymAddr(rs) + r.Add()
 		if r.Type() == objabi.R_LOONG64_TLS_LE_LO {
-			return int64(val&0xffc003ff | ((t & 0xfff) << 10)), noExtReloc, isOk
+			return val&0xffc003ff | ((t & 0xfff) << 10), noExtReloc, isOk
 		}
-		return int64(val&0xfe00001f | (((t) >> 12 << 5) & 0x1ffffe0)), noExtReloc, isOk
+		return val&0xfe00001f | (((t) >> 12 << 5) & 0x1ffffe0), noExtReloc, isOk
 	case objabi.R_CALLLOONG64,
 		objabi.R_JMPLOONG64:
 		pc := ldr.SymValue(s) + int64(r.Off())
 		t := ldr.SymAddr(rs) + r.Add() - pc
-		return int64(val&0xfc000000 | (((t >> 2) & 0xffff) << 10) | (((t >> 2) & 0x3ff0000) >> 16)), noExtReloc, isOk
+		return val&0xfc000000 | (((t >> 2) & 0xffff) << 10) | (((t >> 2) & 0x3ff0000) >> 16), noExtReloc, isOk
 
 	case objabi.R_JMP16LOONG64,
 		objabi.R_JMP21LOONG64:
 		pc := ldr.SymValue(s) + int64(r.Off())
 		t := ldr.SymAddr(rs) + r.Add() - pc
 		if r.Type() == objabi.R_JMP16LOONG64 {
-			return int64(val&0xfc0003ff | (((t >> 2) & 0xffff) << 10)), noExtReloc, isOk
+			return val&0xfc0003ff | (((t >> 2) & 0xffff) << 10), noExtReloc, isOk
 		}
-		return int64(val&0xfc0003e0 | (((t >> 2) & 0xffff) << 10) | (((t >> 2) & 0x1f0000) >> 16)), noExtReloc, isOk
+		return val&0xfc0003e0 | (((t >> 2) & 0xffff) << 10) | (((t >> 2) & 0x1f0000) >> 16), noExtReloc, isOk
 
 	case objabi.R_LOONG64_TLS_IE_HI,
 		objabi.R_LOONG64_TLS_IE_LO:
@@ -540,9 +540,9 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
 
 	case objabi.R_LOONG64_ADD64, objabi.R_LOONG64_SUB64:
 		if r.Type() == objabi.R_LOONG64_ADD64 {
-			return int64(val + ldr.SymAddr(rs) + r.Add()), noExtReloc, isOk
+			return val + ldr.SymAddr(rs) + r.Add(), noExtReloc, isOk
 		}
-		return int64(val - (ldr.SymAddr(rs) + r.Add())), noExtReloc, isOk
+		return val - (ldr.SymAddr(rs) + r.Add()), noExtReloc, isOk
 	}
 
 	return val, 0, false
@@ -628,7 +628,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
 			for i := 0; ; i++ {
 				oName := ldr.SymName(rs)
 				name := oName + fmt.Sprintf("%+x-tramp%d", r.Add(), i)
-				tramp = ldr.LookupOrCreateSym(name, int(ldr.SymVersion(rs)))
+				tramp = ldr.LookupOrCreateSym(name, ldr.SymVersion(rs))
 				ldr.SetAttrReachable(tramp, true)
 				if ldr.SymType(tramp) == sym.SDYNIMPORT {
 					// don't reuse trampoline defined in other module
diff --git a/src/cmd/link/internal/mips64/asm.go b/src/cmd/link/internal/mips64/asm.go
index e82d9861841109..a86ded65f289fc 100644
--- a/src/cmd/link/internal/mips64/asm.go
+++ b/src/cmd/link/internal/mips64/asm.go
@@ -298,9 +298,9 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
 		objabi.R_ADDRMIPSU:
 		t := ldr.SymValue(rs) + r.Add()
 		if r.Type() == objabi.R_ADDRMIPS {
-			return int64(val&0xffff0000 | t&0xffff), noExtReloc, isOk
+			return val&0xffff0000 | t&0xffff, noExtReloc, isOk
 		}
-		return int64(val&0xffff0000 | ((t+1<<15)>>16)&0xffff), noExtReloc, isOk
+		return val&0xffff0000 | ((t+1<<15)>>16)&0xffff, noExtReloc, isOk
 	case objabi.R_ADDRMIPSTLS:
 		// thread pointer is at 0x7000 offset from the start of TLS data area
 		t := ldr.SymValue(rs) + r.Add() - 0x7000
@@ -312,12 +312,12 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
 		if t < -32768 || t >= 32678 {
 			ldr.Errorf(s, "TLS offset out of range %d", t)
 		}
-		return int64(val&0xffff0000 | t&0xffff), noExtReloc, isOk
+		return val&0xffff0000 | t&0xffff, noExtReloc, isOk
 	case objabi.R_CALLMIPS,
 		objabi.R_JMPMIPS:
 		// Low 26 bits = (S + A) >> 2
 		t := ldr.SymValue(rs) + r.Add()
-		return int64(val&0xfc000000 | (t>>2)&^0xfc000000), noExtReloc, isOk
+		return val&0xfc000000 | (t>>2)&^0xfc000000, noExtReloc, isOk
 	}
 
 	return val, 0, false
diff --git a/src/cmd/link/internal/ppc64/asm.go b/src/cmd/link/internal/ppc64/asm.go
index af7cddff7f0730..5ceab3aa5a1255 100644
--- a/src/cmd/link/internal/ppc64/asm.go
+++ b/src/cmd/link/internal/ppc64/asm.go
@@ -853,7 +853,7 @@ func addelfdynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s lo
 		} else {
 			ldr.Errorf(s, "unexpected relocation for dynamic symbol %s", ldr.SymName(targ))
 		}
-		rela.AddAddrPlus(target.Arch, targ, int64(r.Add()))
+		rela.AddAddrPlus(target.Arch, targ, r.Add())
 
 		// Not mark r done here. So we still apply it statically,
 		// so in the file content we'll also have the right offset
@@ -1208,7 +1208,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
 
 				// Look up the trampoline in case it already exists
 
-				tramp = ldr.LookupOrCreateSym(name, int(ldr.SymVersion(rs)))
+				tramp = ldr.LookupOrCreateSym(name, ldr.SymVersion(rs))
 				if oName == "runtime.deferreturn" {
 					ldr.SetIsDeferReturnTramp(tramp, true)
 				}
diff --git a/src/cmd/link/internal/riscv64/asm.go b/src/cmd/link/internal/riscv64/asm.go
index f85658372775e3..9d69152af0ec35 100644
--- a/src/cmd/link/internal/riscv64/asm.go
+++ b/src/cmd/link/internal/riscv64/asm.go
@@ -497,7 +497,7 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
 		}
 		immMask := int64(riscv.JTypeImmMask)
 
-		val = (val &^ immMask) | int64(imm)
+		val = (val &^ immMask) | imm
 
 		return val, 0, true
 
@@ -719,7 +719,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
 			if r.Add() != 0 {
 				name = fmt.Sprintf("%s%+x-tramp%d", oName, r.Add(), i)
 			}
-			tramp = ldr.LookupOrCreateSym(name, int(ldr.SymVersion(rs)))
+			tramp = ldr.LookupOrCreateSym(name, ldr.SymVersion(rs))
 			ldr.SetAttrReachable(tramp, true)
 			if ldr.SymType(tramp) == sym.SDYNIMPORT {
 				// Do not reuse trampoline defined in other module.
@@ -744,7 +744,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
 		if ldr.SymType(tramp) == 0 {
 			trampb := ldr.MakeSymbolUpdater(tramp)
 			ctxt.AddTramp(trampb, ldr.SymType(s))
-			genCallTramp(ctxt.Arch, ctxt.LinkMode, ldr, trampb, rs, int64(r.Add()))
+			genCallTramp(ctxt.Arch, ctxt.LinkMode, ldr, trampb, rs, r.Add())
 		}
 		sb := ldr.MakeSymbolUpdater(s)
 		if ldr.SymValue(rs) == 0 {
diff --git a/src/cmd/link/internal/wasm/asm.go b/src/cmd/link/internal/wasm/asm.go
index d03102cc6be629..2ddf5b33ba273a 100644
--- a/src/cmd/link/internal/wasm/asm.go
+++ b/src/cmd/link/internal/wasm/asm.go
@@ -302,11 +302,11 @@ func writeTypeSec(ctxt *ld.Link, types []*wasmFuncType) {
 		ctxt.Out.WriteByte(0x60) // functype
 		writeUleb128(ctxt.Out, uint64(len(t.Params)))
 		for _, v := range t.Params {
-			ctxt.Out.WriteByte(byte(v))
+			ctxt.Out.WriteByte(v)
 		}
 		writeUleb128(ctxt.Out, uint64(len(t.Results)))
 		for _, v := range t.Results {
-			ctxt.Out.WriteByte(byte(v))
+			ctxt.Out.WriteByte(v)
 		}
 	}
 
diff --git a/src/cmd/trace/gstate.go b/src/cmd/trace/gstate.go
index 9c3da66217fd07..46638a1cdbe7f8 100644
--- a/src/cmd/trace/gstate.go
+++ b/src/cmd/trace/gstate.go
@@ -147,7 +147,7 @@ func (gs *gState[R]) start(ts trace.Time, resource R, ctx *traceContext) {
 			Name:         gs.startCause.name,
 			Start:        ctx.elapsed(gs.startCause.time),
 			End:          ctx.elapsed(ts),
-			FromResource: uint64(gs.startCause.resource),
+			FromResource: gs.startCause.resource,
 			ToResource:   uint64(resource),
 			FromStack:    ctx.Stack(viewerFrames(gs.startCause.stack)),
 		})
diff --git a/src/net/cgo_unix_syscall.go b/src/net/cgo_unix_syscall.go
index 9cfc5783721646..6b7ef74bd2b945 100644
--- a/src/net/cgo_unix_syscall.go
+++ b/src/net/cgo_unix_syscall.go
@@ -84,8 +84,7 @@ func _C_res_nclose(state *_C_struct___res_state) {
 }
 
 func cgoNameinfoPTR(b []byte, sa *syscall.RawSockaddr, salen int) (int, error) {
-	gerrno, err := unix.Getnameinfo(sa, salen, &b[0], len(b), nil, 0, unix.NI_NAMEREQD)
-	return int(gerrno), err
+	return unix.Getnameinfo(sa, salen, &b[0], len(b), nil, 0, unix.NI_NAMEREQD)
 }
 
 func cgoSockaddrInet4(ip IP) *syscall.RawSockaddr {
diff --git a/src/runtime/metrics.go b/src/runtime/metrics.go
index 36efef39c032c7..6ee2c285493473 100644
--- a/src/runtime/metrics.go
+++ b/src/runtime/metrics.go
@@ -469,42 +469,42 @@ func initMetrics() {
 			deps: makeStatDepSet(schedStatsDep),
 			compute: func(in *statAggregate, out *metricValue) {
 				out.kind = metricKindUint64
-				out.scalar = uint64(in.schedStats.gTotal)
+				out.scalar = in.schedStats.gTotal
 			},
 		},
 		"/sched/goroutines/not-in-go:goroutines": {
 			deps: makeStatDepSet(schedStatsDep),
 			compute: func(in *statAggregate, out *metricValue) {
 				out.kind = metricKindUint64
-				out.scalar = uint64(in.schedStats.gNonGo)
+				out.scalar = in.schedStats.gNonGo
 			},
 		},
 		"/sched/goroutines/running:goroutines": {
 			deps: makeStatDepSet(schedStatsDep),
 			compute: func(in *statAggregate, out *metricValue) {
 				out.kind = metricKindUint64
-				out.scalar = uint64(in.schedStats.gRunning)
+				out.scalar = in.schedStats.gRunning
 			},
 		},
 		"/sched/goroutines/runnable:goroutines": {
 			deps: makeStatDepSet(schedStatsDep),
 			compute: func(in *statAggregate, out *metricValue) {
 				out.kind = metricKindUint64
-				out.scalar = uint64(in.schedStats.gRunnable)
+				out.scalar = in.schedStats.gRunnable
 			},
 		},
 		"/sched/goroutines/waiting:goroutines": {
 			deps: makeStatDepSet(schedStatsDep),
 			compute: func(in *statAggregate, out *metricValue) {
 				out.kind = metricKindUint64
-				out.scalar = uint64(in.schedStats.gWaiting)
+				out.scalar = in.schedStats.gWaiting
 			},
 		},
 		"/sched/goroutines-created:goroutines": {
 			deps: makeStatDepSet(schedStatsDep),
 			compute: func(in *statAggregate, out *metricValue) {
 				out.kind = metricKindUint64
-				out.scalar = uint64(in.schedStats.gCreated)
+				out.scalar = in.schedStats.gCreated
 			},
 		},
 		"/sched/latencies:seconds": {
@@ -536,7 +536,7 @@ func initMetrics() {
 			deps: makeStatDepSet(schedStatsDep),
 			compute: func(in *statAggregate, out *metricValue) {
 				out.kind = metricKindUint64
-				out.scalar = uint64(in.schedStats.threads)
+				out.scalar = in.schedStats.threads
 			},
 		},
 		"/sync/mutex/wait/total:seconds": {

From 306eacbc112f2052d82c419fe312153b8b2ab613 Mon Sep 17 00:00:00 2001
From: matloob 
Date: Mon, 20 Oct 2025 13:51:13 -0400
Subject: [PATCH 210/229] cmd/go/testdata/script: disable list_empty_importpath
 test on Windows

The test is flaking on windows, and I haven't been able to figure out
why. For now, to unblock folks, just allow the value that occasionally
appears: 'no errors' to avoid having a broken test. This seems like it's
probably a race though so we should fix it as soon as we can.

For #73976

Change-Id: I6a6a696431d784d048ed798b828a759e752b6393
Reviewed-on: https://go-review.googlesource.com/c/go/+/713220
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Michael Matloob 
Reviewed-by: Alan Donovan 
Reviewed-by: Michael Matloob 
---
 src/cmd/go/testdata/script/list_empty_importpath.txt | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/cmd/go/testdata/script/list_empty_importpath.txt b/src/cmd/go/testdata/script/list_empty_importpath.txt
index 0960a7795d12ea..4ddf6b36d26881 100644
--- a/src/cmd/go/testdata/script/list_empty_importpath.txt
+++ b/src/cmd/go/testdata/script/list_empty_importpath.txt
@@ -1,6 +1,12 @@
 ! go list all
 ! stderr 'panic'
-stderr 'invalid import path'
+[!GOOS:windows] [!GOOS:solaris] stderr 'invalid import path'
+# #73976: Allow 'no errors' on Windows and Solaris until issue
+# is resolved to prevent flakes. 'no errors' is printed by
+# empty scanner.ErrorList errors so that's probably where the
+# message is coming from, though we don't know how.
+[GOOS:windows] stderr 'invalid import path|no errors'
+[GOOS:solaris] stderr 'invalid import path|no errors'
 
 # go list produces a package for 'p' but not for ''
 go list -e all

From 2163a5802103ebe84cbf0d77cee7097185bd8e8d Mon Sep 17 00:00:00 2001
From: qmuntal 
Date: Fri, 17 Oct 2025 12:40:05 +0200
Subject: [PATCH 211/229] crypto/internal/fips140/entropy: increase
 AllocsPerRun iterations

TestNISTECAllocations is flaky (~1% failure rate) on my local Windows
machine since CL 710058, which touched TestEntropyRace.

These tests are unrelated, but some allocations might be incorrectly
accounted to TestNISTECAllocations, affecting the end result due to
the low number of iterations done in that test.

Change-Id: I01323c2a45b12665e86d940467f4f91c2e66696b
Reviewed-on: https://go-review.googlesource.com/c/go/+/712620
Reviewed-by: David Chase 
Reviewed-by: Roland Shoemaker 
Auto-Submit: Quim Muntal 
LUCI-TryBot-Result: Go LUCI 
---
 src/crypto/internal/fips140test/nistec_test.go | 8 ++++----
 src/crypto/internal/fips140test/xaes_test.go   | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/crypto/internal/fips140test/nistec_test.go b/src/crypto/internal/fips140test/nistec_test.go
index 3b3de2bc2cb1f6..9b4b7cba7fa3e7 100644
--- a/src/crypto/internal/fips140test/nistec_test.go
+++ b/src/crypto/internal/fips140test/nistec_test.go
@@ -18,7 +18,7 @@ import (
 func TestNISTECAllocations(t *testing.T) {
 	cryptotest.SkipTestAllocations(t)
 	t.Run("P224", func(t *testing.T) {
-		if allocs := testing.AllocsPerRun(10, func() {
+		if allocs := testing.AllocsPerRun(100, func() {
 			p := nistec.NewP224Point().SetGenerator()
 			scalar := make([]byte, 28)
 			rand.Read(scalar)
@@ -37,7 +37,7 @@ func TestNISTECAllocations(t *testing.T) {
 		}
 	})
 	t.Run("P256", func(t *testing.T) {
-		if allocs := testing.AllocsPerRun(10, func() {
+		if allocs := testing.AllocsPerRun(100, func() {
 			p := nistec.NewP256Point().SetGenerator()
 			scalar := make([]byte, 32)
 			rand.Read(scalar)
@@ -56,7 +56,7 @@ func TestNISTECAllocations(t *testing.T) {
 		}
 	})
 	t.Run("P384", func(t *testing.T) {
-		if allocs := testing.AllocsPerRun(10, func() {
+		if allocs := testing.AllocsPerRun(100, func() {
 			p := nistec.NewP384Point().SetGenerator()
 			scalar := make([]byte, 48)
 			rand.Read(scalar)
@@ -75,7 +75,7 @@ func TestNISTECAllocations(t *testing.T) {
 		}
 	})
 	t.Run("P521", func(t *testing.T) {
-		if allocs := testing.AllocsPerRun(10, func() {
+		if allocs := testing.AllocsPerRun(100, func() {
 			p := nistec.NewP521Point().SetGenerator()
 			scalar := make([]byte, 66)
 			rand.Read(scalar)
diff --git a/src/crypto/internal/fips140test/xaes_test.go b/src/crypto/internal/fips140test/xaes_test.go
index 9406bfab7bf5cc..c852832fcea713 100644
--- a/src/crypto/internal/fips140test/xaes_test.go
+++ b/src/crypto/internal/fips140test/xaes_test.go
@@ -21,7 +21,7 @@ func TestXAESAllocations(t *testing.T) {
 		t.Skip("Test reports non-zero allocation count. See issue #70448")
 	}
 	cryptotest.SkipTestAllocations(t)
-	if allocs := testing.AllocsPerRun(10, func() {
+	if allocs := testing.AllocsPerRun(100, func() {
 		key := make([]byte, 32)
 		nonce := make([]byte, 24)
 		plaintext := make([]byte, 16)

From 46cc53290003340877413b8a53511b4f3685d213 Mon Sep 17 00:00:00 2001
From: Jes Cok 
Date: Mon, 20 Oct 2025 16:18:42 +0000
Subject: [PATCH 212/229] cmd/compile/internal/ssa: fix typo in comment

Change-Id: Ic48a756b71a62be1c6c4cfe781c02b89010e2338
GitHub-Last-Rev: 8c0d89b475c204af66d528799713276c57da16f8
GitHub-Pull-Request: golang/go#75985
Reviewed-on: https://go-review.googlesource.com/c/go/+/713041
Reviewed-by: Keith Randall 
Reviewed-by: Keith Randall 
Reviewed-by: Jorropo 
Reviewed-by: David Chase 
Auto-Submit: Keith Randall 
Auto-Submit: Jorropo 
LUCI-TryBot-Result: Go LUCI 
---
 src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go b/src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go
index dc433ff9749150..99f8f036379e7b 100644
--- a/src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go
+++ b/src/cmd/compile/internal/ssa/_gen/RISCV64Ops.go
@@ -99,7 +99,7 @@ func init() {
 		}
 	}
 
-	// Floating pointer registers.
+	// Floating point registers.
 	for r := 32; r <= 63; r++ {
 		mask := addreg(r, "")
 		fpMask |= mask

From b31dc77ceab962c0f4f5e4a9fc5e1a403fbd2d7c Mon Sep 17 00:00:00 2001
From: qmuntal 
Date: Tue, 21 Oct 2025 16:14:03 +0200
Subject: [PATCH 213/229] os: support deleting read-only files in RemoveAll on
 older Windows versions

The Windows implementation of RemoveAll supports deleting read-only
files only on file systems that supports POSIX semantics and on
newer Windows versions (Windows 10 RS5 and latter).

For all the other cases, the read-only bit was not clearer before
deleting read-only files, so they fail to delete.

Note that this case was supported prior to CL 75922, which landed on
Go 1.25.

Fixes #75922

Change-Id: Id6e6477f42e1952d08318ca3e4ab7c1648969f66
Reviewed-on: https://go-review.googlesource.com/c/go/+/713480
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: David Chase 
Reviewed-by: Damien Neil 
Auto-Submit: Damien Neil 
---
 src/internal/syscall/windows/at_windows.go    | 77 ++++++++++++++-----
 .../syscall/windows/symlink_windows.go        |  1 +
 .../syscall/windows/syscall_windows.go        |  5 ++
 src/internal/syscall/windows/types_windows.go |  5 ++
 .../syscall/windows/zsyscall_windows.go       | 10 +++
 src/os/path_windows_test.go                   | 17 ++++
 6 files changed, 95 insertions(+), 20 deletions(-)

diff --git a/src/internal/syscall/windows/at_windows.go b/src/internal/syscall/windows/at_windows.go
index 8dc3ac0e40fc67..2890e1fdcfc511 100644
--- a/src/internal/syscall/windows/at_windows.go
+++ b/src/internal/syscall/windows/at_windows.go
@@ -209,7 +209,7 @@ func Deleteat(dirfd syscall.Handle, name string, options uint32) error {
 	var h syscall.Handle
 	err := NtOpenFile(
 		&h,
-		SYNCHRONIZE|DELETE,
+		SYNCHRONIZE|FILE_READ_ATTRIBUTES|DELETE,
 		objAttrs,
 		&IO_STATUS_BLOCK{},
 		FILE_SHARE_DELETE|FILE_SHARE_READ|FILE_SHARE_WRITE,
@@ -220,14 +220,22 @@ func Deleteat(dirfd syscall.Handle, name string, options uint32) error {
 	}
 	defer syscall.CloseHandle(h)
 
-	const (
-		FileDispositionInformation   = 13
-		FileDispositionInformationEx = 64
-	)
+	if TestDeleteatFallback {
+		return deleteatFallback(h)
+	}
+
+	const FileDispositionInformationEx = 64
 
 	// First, attempt to delete the file using POSIX semantics
 	// (which permit a file to be deleted while it is still open).
 	// This matches the behavior of DeleteFileW.
+	//
+	// The following call uses features available on different Windows versions:
+	// - FILE_DISPOSITION_INFORMATION_EX: Windows 10, version 1607 (aka RS1)
+	// - FILE_DISPOSITION_POSIX_SEMANTICS: Windows 10, version 1607 (aka RS1)
+	// - FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE: Windows 10, version 1809 (aka RS5)
+	//
+	// Also, some file systems, like FAT32, don't support POSIX semantics.
 	err = NtSetInformationFile(
 		h,
 		&IO_STATUS_BLOCK{},
@@ -246,28 +254,57 @@ func Deleteat(dirfd syscall.Handle, name string, options uint32) error {
 	switch err {
 	case nil:
 		return nil
-	case STATUS_CANNOT_DELETE, STATUS_DIRECTORY_NOT_EMPTY:
+	case STATUS_INVALID_INFO_CLASS, // the operating system doesn't support FileDispositionInformationEx
+		STATUS_INVALID_PARAMETER, // the operating system doesn't support one of the flags
+		STATUS_NOT_SUPPORTED:     // the file system doesn't support FILE_DISPOSITION_INFORMATION_EX or one of the flags
+		return deleteatFallback(h)
+	default:
 		return err.(NTStatus).Errno()
 	}
+}
 
-	// If the prior deletion failed, the filesystem either doesn't support
-	// POSIX semantics (for example, FAT), or hasn't implemented
-	// FILE_DISPOSITION_INFORMATION_EX.
-	//
-	// Try again.
-	err = NtSetInformationFile(
+// TestDeleteatFallback should only be used for testing purposes.
+// When set, [Deleteat] uses the fallback path unconditionally.
+var TestDeleteatFallback bool
+
+// deleteatFallback is a deleteat implementation that strives
+// for compatibility with older Windows versions and file systems
+// over performance.
+func deleteatFallback(h syscall.Handle) error {
+	var data syscall.ByHandleFileInformation
+	if err := syscall.GetFileInformationByHandle(h, &data); err == nil && data.FileAttributes&syscall.FILE_ATTRIBUTE_READONLY != 0 {
+		// Remove read-only attribute. Reopen the file, as it was previously open without FILE_WRITE_ATTRIBUTES access
+		// in order to maximize compatibility in the happy path.
+		wh, err := ReOpenFile(h,
+			FILE_WRITE_ATTRIBUTES,
+			FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,
+			syscall.FILE_FLAG_OPEN_REPARSE_POINT|syscall.FILE_FLAG_BACKUP_SEMANTICS,
+		)
+		if err != nil {
+			return err
+		}
+		err = SetFileInformationByHandle(
+			wh,
+			FileBasicInfo,
+			unsafe.Pointer(&FILE_BASIC_INFO{
+				FileAttributes: data.FileAttributes &^ FILE_ATTRIBUTE_READONLY,
+			}),
+			uint32(unsafe.Sizeof(FILE_BASIC_INFO{})),
+		)
+		syscall.CloseHandle(wh)
+		if err != nil {
+			return err
+		}
+	}
+
+	return SetFileInformationByHandle(
 		h,
-		&IO_STATUS_BLOCK{},
-		unsafe.Pointer(&FILE_DISPOSITION_INFORMATION{
+		FileDispositionInfo,
+		unsafe.Pointer(&FILE_DISPOSITION_INFO{
 			DeleteFile: true,
 		}),
-		uint32(unsafe.Sizeof(FILE_DISPOSITION_INFORMATION{})),
-		FileDispositionInformation,
+		uint32(unsafe.Sizeof(FILE_DISPOSITION_INFO{})),
 	)
-	if st, ok := err.(NTStatus); ok {
-		return st.Errno()
-	}
-	return err
 }
 
 func Renameat(olddirfd syscall.Handle, oldpath string, newdirfd syscall.Handle, newpath string) error {
diff --git a/src/internal/syscall/windows/symlink_windows.go b/src/internal/syscall/windows/symlink_windows.go
index b91246037b5efe..b8249b3848ea02 100644
--- a/src/internal/syscall/windows/symlink_windows.go
+++ b/src/internal/syscall/windows/symlink_windows.go
@@ -19,6 +19,7 @@ const (
 	FileBasicInfo                  = 0    // FILE_BASIC_INFO
 	FileStandardInfo               = 1    // FILE_STANDARD_INFO
 	FileNameInfo                   = 2    // FILE_NAME_INFO
+	FileDispositionInfo            = 4    // FILE_DISPOSITION_INFO
 	FileStreamInfo                 = 7    // FILE_STREAM_INFO
 	FileCompressionInfo            = 8    // FILE_COMPRESSION_INFO
 	FileAttributeTagInfo           = 9    // FILE_ATTRIBUTE_TAG_INFO
diff --git a/src/internal/syscall/windows/syscall_windows.go b/src/internal/syscall/windows/syscall_windows.go
index fb3b66540f1c9d..deea3f35ca8d25 100644
--- a/src/internal/syscall/windows/syscall_windows.go
+++ b/src/internal/syscall/windows/syscall_windows.go
@@ -531,6 +531,8 @@ const (
 //sys	GetOverlappedResult(handle syscall.Handle, overlapped *syscall.Overlapped, done *uint32, wait bool) (err error)
 //sys	CreateNamedPipe(name *uint16, flags uint32, pipeMode uint32, maxInstances uint32, outSize uint32, inSize uint32, defaultTimeout uint32, sa *syscall.SecurityAttributes) (handle syscall.Handle, err error)  [failretval==syscall.InvalidHandle] = CreateNamedPipeW
 
+//sys	ReOpenFile(filehandle syscall.Handle, desiredAccess uint32, shareMode uint32, flagAndAttributes uint32) (handle syscall.Handle, err error)
+
 // NTStatus corresponds with NTSTATUS, error values returned by ntdll.dll and
 // other native functions.
 type NTStatus uint32
@@ -556,6 +558,9 @@ const (
 	STATUS_NOT_A_DIRECTORY           NTStatus = 0xC0000103
 	STATUS_CANNOT_DELETE             NTStatus = 0xC0000121
 	STATUS_REPARSE_POINT_ENCOUNTERED NTStatus = 0xC000050B
+	STATUS_NOT_SUPPORTED             NTStatus = 0xC00000BB
+	STATUS_INVALID_PARAMETER         NTStatus = 0xC000000D
+	STATUS_INVALID_INFO_CLASS        NTStatus = 0xC0000003
 )
 
 const (
diff --git a/src/internal/syscall/windows/types_windows.go b/src/internal/syscall/windows/types_windows.go
index fe9e41f2f866bf..49daf9b31b1ff7 100644
--- a/src/internal/syscall/windows/types_windows.go
+++ b/src/internal/syscall/windows/types_windows.go
@@ -216,6 +216,11 @@ const (
 	FILE_OPEN_FOR_FREE_SPACE_QUERY = 0x00800000
 )
 
+// https://learn.microsoft.com/en-us/windows/win32/api/winbase/ns-winbase-file_disposition_info
+type FILE_DISPOSITION_INFO struct {
+	DeleteFile bool
+}
+
 // https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/ntddk/ns-ntddk-_file_disposition_information
 type FILE_DISPOSITION_INFORMATION struct {
 	DeleteFile bool
diff --git a/src/internal/syscall/windows/zsyscall_windows.go b/src/internal/syscall/windows/zsyscall_windows.go
index 70c4d76dff0d0f..64bb5041073946 100644
--- a/src/internal/syscall/windows/zsyscall_windows.go
+++ b/src/internal/syscall/windows/zsyscall_windows.go
@@ -86,6 +86,7 @@ var (
 	procModule32NextW                     = modkernel32.NewProc("Module32NextW")
 	procMoveFileExW                       = modkernel32.NewProc("MoveFileExW")
 	procMultiByteToWideChar               = modkernel32.NewProc("MultiByteToWideChar")
+	procReOpenFile                        = modkernel32.NewProc("ReOpenFile")
 	procRtlLookupFunctionEntry            = modkernel32.NewProc("RtlLookupFunctionEntry")
 	procRtlVirtualUnwind                  = modkernel32.NewProc("RtlVirtualUnwind")
 	procSetFileInformationByHandle        = modkernel32.NewProc("SetFileInformationByHandle")
@@ -440,6 +441,15 @@ func MultiByteToWideChar(codePage uint32, dwFlags uint32, str *byte, nstr int32,
 	return
 }
 
+func ReOpenFile(filehandle syscall.Handle, desiredAccess uint32, shareMode uint32, flagAndAttributes uint32) (handle syscall.Handle, err error) {
+	r0, _, e1 := syscall.SyscallN(procReOpenFile.Addr(), uintptr(filehandle), uintptr(desiredAccess), uintptr(shareMode), uintptr(flagAndAttributes))
+	handle = syscall.Handle(r0)
+	if handle == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func RtlLookupFunctionEntry(pc uintptr, baseAddress *uintptr, table unsafe.Pointer) (ret *RUNTIME_FUNCTION) {
 	r0, _, _ := syscall.SyscallN(procRtlLookupFunctionEntry.Addr(), uintptr(pc), uintptr(unsafe.Pointer(baseAddress)), uintptr(table))
 	ret = (*RUNTIME_FUNCTION)(unsafe.Pointer(r0))
diff --git a/src/os/path_windows_test.go b/src/os/path_windows_test.go
index 3fa02e2a65b083..eea2b58ee0a886 100644
--- a/src/os/path_windows_test.go
+++ b/src/os/path_windows_test.go
@@ -236,6 +236,23 @@ func TestRemoveAllLongPathRelative(t *testing.T) {
 	}
 }
 
+func TestRemoveAllFallback(t *testing.T) {
+	windows.TestDeleteatFallback = true
+	t.Cleanup(func() { windows.TestDeleteatFallback = false })
+
+	dir := t.TempDir()
+	if err := os.WriteFile(filepath.Join(dir, "file1"), []byte{}, 0700); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "file2"), []byte{}, 0400); err != nil { // read-only file
+		t.Fatal(err)
+	}
+
+	if err := os.RemoveAll(dir); err != nil {
+		t.Fatal(err)
+	}
+}
+
 func testLongPathAbs(t *testing.T, target string) {
 	t.Helper()
 	testWalkFn := func(path string, info os.FileInfo, err error) error {

From 4620db72d273097a1c5fd11e44ce688618559579 Mon Sep 17 00:00:00 2001
From: abdullahkiani007 
Date: Sat, 18 Oct 2025 14:43:53 +0000
Subject: [PATCH 214/229] runtime: use timer_settime64 on 32-bit Linux

Linux introduced new syscalls to fix the year 2038 issue.
To still be able to use the old ones, the Kconfig option
COMPAT_32BIT_TIME would be necessary.

Use the new 64-bit syscall for timer_settime by default.
Add a fallback to use the 32-bit syscall when the
64-bit version returns _ENOSYS.

Fixes #75133

Change-Id: Iccb8831b67f665067ee526e93c3ff2f4f5392edf
GitHub-Last-Rev: 6c3d62d60e5ff02ebe61e56e06d6365e530ec39e
GitHub-Pull-Request: golang/go#75957
Reviewed-on: https://go-review.googlesource.com/c/go/+/712642
Reviewed-by: Jorropo 
Reviewed-by: David Chase 
Reviewed-by: Dmitri Shuralyov 
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Jorropo 
---
 src/runtime/defs_linux_386.go     |  6 +++-
 src/runtime/defs_linux_arm.go     |  7 ++++-
 src/runtime/defs_linux_mipsx.go   |  7 ++++-
 src/runtime/os_linux.go           |  3 --
 src/runtime/os_linux_settime32.go | 47 +++++++++++++++++++++++++++++++
 src/runtime/os_linux_settime64.go | 10 +++++++
 src/runtime/sys_linux_386.s       | 14 ++++++++-
 src/runtime/sys_linux_arm.s       | 15 ++++++++--
 src/runtime/sys_linux_mipsx.s     | 14 ++++++++-
 9 files changed, 113 insertions(+), 10 deletions(-)
 create mode 100644 src/runtime/os_linux_settime32.go
 create mode 100644 src/runtime/os_linux_settime64.go

diff --git a/src/runtime/defs_linux_386.go b/src/runtime/defs_linux_386.go
index e902d8175c3b0d..c6c7d7d6d880c0 100644
--- a/src/runtime/defs_linux_386.go
+++ b/src/runtime/defs_linux_386.go
@@ -237,10 +237,14 @@ type ucontext struct {
 	uc_sigmask  uint32
 }
 
-type itimerspec struct {
+type itimerspec32 struct {
 	it_interval timespec32
 	it_value    timespec32
 }
+type itimerspec struct {
+	it_interval timespec
+	it_value    timespec
+}
 
 type itimerval struct {
 	it_interval timeval
diff --git a/src/runtime/defs_linux_arm.go b/src/runtime/defs_linux_arm.go
index 35c4faf96405d3..ff879fad89faa1 100644
--- a/src/runtime/defs_linux_arm.go
+++ b/src/runtime/defs_linux_arm.go
@@ -169,11 +169,16 @@ func (tv *timeval) set_usec(x int32) {
 	tv.tv_usec = x
 }
 
-type itimerspec struct {
+type itimerspec32 struct {
 	it_interval timespec32
 	it_value    timespec32
 }
 
+type itimerspec struct {
+	it_interval timespec
+	it_value    timespec
+}
+
 type itimerval struct {
 	it_interval timeval
 	it_value    timeval
diff --git a/src/runtime/defs_linux_mipsx.go b/src/runtime/defs_linux_mipsx.go
index cec504c885662b..5b10b910dbebf2 100644
--- a/src/runtime/defs_linux_mipsx.go
+++ b/src/runtime/defs_linux_mipsx.go
@@ -152,11 +152,16 @@ type siginfo struct {
 	_ [_si_max_size - unsafe.Sizeof(siginfoFields{})]byte
 }
 
-type itimerspec struct {
+type itimerspec32 struct {
 	it_interval timespec32
 	it_value    timespec32
 }
 
+type itimerspec struct {
+	it_interval timespec
+	it_value    timespec
+}
+
 type itimerval struct {
 	it_interval timeval
 	it_value    timeval
diff --git a/src/runtime/os_linux.go b/src/runtime/os_linux.go
index 080dd9653232ed..1b7d5731cc32ab 100644
--- a/src/runtime/os_linux.go
+++ b/src/runtime/os_linux.go
@@ -435,9 +435,6 @@ func setitimer(mode int32, new, old *itimerval)
 //go:noescape
 func timer_create(clockid int32, sevp *sigevent, timerid *int32) int32
 
-//go:noescape
-func timer_settime(timerid int32, flags int32, new, old *itimerspec) int32
-
 //go:noescape
 func timer_delete(timerid int32) int32
 
diff --git a/src/runtime/os_linux_settime32.go b/src/runtime/os_linux_settime32.go
new file mode 100644
index 00000000000000..6df7f21dc9ce71
--- /dev/null
+++ b/src/runtime/os_linux_settime32.go
@@ -0,0 +1,47 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux && (386 || arm || mips || mipsle)
+
+package runtime
+
+import "internal/runtime/atomic"
+
+var timer32bitOnly atomic.Bool
+
+//go:noescape
+func timer_settime32(timerid int32, flags int32, new, old *itimerspec32) int32
+
+//go:noescape
+func timer_settime64(timerid int32, flags int32, new, old *itimerspec) int32
+
+//go:nosplit
+func timer_settime(timerid int32, flags int32, new, old *itimerspec) int32 {
+	if !timer32bitOnly.Load() {
+		ret := timer_settime64(timerid, flags, new, old)
+		// timer_settime64 is only supported on Linux 5.0+
+		if ret != -_ENOSYS {
+			return ret
+		}
+		timer32bitOnly.Store(true)
+	}
+
+	var newts,oldts itimerspec32
+	var new32,old32 *itimerspec32
+
+	if new != nil {
+		newts.it_interval.setNsec(new.it_interval.tv_sec*1e9 + new.it_interval.tv_nsec)
+		newts.it_value.setNsec(new.it_value.tv_sec*1e9 + new.it_value.tv_nsec)
+		new32 = &newts
+	}
+
+	if old != nil {
+		oldts.it_interval.setNsec(old.it_interval.tv_sec*1e9 + old.it_interval.tv_nsec)
+		oldts.it_value.setNsec(old.it_value.tv_sec*1e9 + old.it_value.tv_nsec)
+		old32 = &oldts
+	}
+
+	// Fall back to 32-bit timer
+	return timer_settime32(timerid, flags, new32, old32)
+}
diff --git a/src/runtime/os_linux_settime64.go b/src/runtime/os_linux_settime64.go
new file mode 100644
index 00000000000000..60650da33fb990
--- /dev/null
+++ b/src/runtime/os_linux_settime64.go
@@ -0,0 +1,10 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux && !(386 || arm || mips || mipsle)
+
+package runtime
+
+//go:noescape
+func timer_settime(timerid int32, flags int32, new, old *itimerspec) int32
diff --git a/src/runtime/sys_linux_386.s b/src/runtime/sys_linux_386.s
index 1c3f1ff3e6e575..f664d8ace7f997 100644
--- a/src/runtime/sys_linux_386.s
+++ b/src/runtime/sys_linux_386.s
@@ -54,6 +54,7 @@
 #define SYS_exit_group		252
 #define SYS_timer_create	259
 #define SYS_timer_settime	260
+#define SYS_timer_settime64	409
 #define SYS_timer_delete	263
 #define SYS_clock_gettime	265
 #define SYS_tgkill		270
@@ -209,7 +210,8 @@ TEXT runtime·timer_create(SB),NOSPLIT,$0-16
 	MOVL	AX, ret+12(FP)
 	RET
 
-TEXT runtime·timer_settime(SB),NOSPLIT,$0-20
+// Linux: kernel/time/posix-timer.c, requiring COMPAT_32BIT_TIME
+TEXT runtime·timer_settime32(SB),NOSPLIT,$0-20
 	MOVL	$SYS_timer_settime, AX
 	MOVL	timerid+0(FP), BX
 	MOVL	flags+4(FP), CX
@@ -219,6 +221,16 @@ TEXT runtime·timer_settime(SB),NOSPLIT,$0-20
 	MOVL	AX, ret+16(FP)
 	RET
 
+TEXT runtime·timer_settime64(SB),NOSPLIT,$0-20
+	MOVL	$SYS_timer_settime64, AX
+	MOVL	timerid+0(FP), BX
+	MOVL	flags+4(FP), CX
+	MOVL	new+8(FP), DX
+	MOVL	old+12(FP), SI
+	INVOKE_SYSCALL
+	MOVL	AX, ret+16(FP)
+	RET
+
 TEXT runtime·timer_delete(SB),NOSPLIT,$0-8
 	MOVL	$SYS_timer_delete, AX
 	MOVL	timerid+0(FP), BX
diff --git a/src/runtime/sys_linux_arm.s b/src/runtime/sys_linux_arm.s
index 44b56ccb9f0094..f19e293d0fc3e0 100644
--- a/src/runtime/sys_linux_arm.s
+++ b/src/runtime/sys_linux_arm.s
@@ -44,6 +44,7 @@
 #define SYS_clock_gettime (SYS_BASE + 263)
 #define SYS_timer_create (SYS_BASE + 257)
 #define SYS_timer_settime (SYS_BASE + 258)
+#define SYS_timer_settime64 (SYS_BASE + 409)
 #define SYS_timer_delete (SYS_BASE + 261)
 #define SYS_pipe2 (SYS_BASE + 359)
 #define SYS_access (SYS_BASE + 33)
@@ -231,8 +232,8 @@ TEXT runtime·timer_create(SB),NOSPLIT,$0-16
 	SWI	$0
 	MOVW	R0, ret+12(FP)
 	RET
-
-TEXT runtime·timer_settime(SB),NOSPLIT,$0-20
+// Linux: kernel/time/posix-timer.c, requiring COMPAT_32BIT_TIME.
+TEXT runtime·timer_settime32(SB),NOSPLIT,$0-20
 	MOVW	timerid+0(FP), R0
 	MOVW	flags+4(FP), R1
 	MOVW	new+8(FP), R2
@@ -242,6 +243,16 @@ TEXT runtime·timer_settime(SB),NOSPLIT,$0-20
 	MOVW	R0, ret+16(FP)
 	RET
 
+TEXT runtime·timer_settime64(SB),NOSPLIT,$0-20
+	MOVW	timerid+0(FP), R0
+	MOVW	flags+4(FP), R1
+	MOVW	new+8(FP), R2
+	MOVW	old+12(FP), R3
+	MOVW	$SYS_timer_settime64, R7
+	SWI	$0
+	MOVW	R0, ret+16(FP)
+	RET
+
 TEXT runtime·timer_delete(SB),NOSPLIT,$0-8
 	MOVW	timerid+0(FP), R0
 	MOVW	$SYS_timer_delete, R7
diff --git a/src/runtime/sys_linux_mipsx.s b/src/runtime/sys_linux_mipsx.s
index 6f11841efc73e2..bc3f84fbb9591e 100644
--- a/src/runtime/sys_linux_mipsx.s
+++ b/src/runtime/sys_linux_mipsx.s
@@ -39,6 +39,7 @@
 #define SYS_exit_group		4246
 #define SYS_timer_create	4257
 #define SYS_timer_settime	4258
+#define SYS_timer_settime64	4409
 #define SYS_timer_delete	4261
 #define SYS_clock_gettime	4263
 #define SYS_tgkill		4266
@@ -197,7 +198,8 @@ TEXT runtime·timer_create(SB),NOSPLIT,$0-16
 	MOVW	R2, ret+12(FP)
 	RET
 
-TEXT runtime·timer_settime(SB),NOSPLIT,$0-20
+// Linux: kernel/time/posix-timer.c, requiring COMPAT_32BIT_TIME
+TEXT runtime·timer_settime32(SB),NOSPLIT,$0-20
 	MOVW	timerid+0(FP), R4
 	MOVW	flags+4(FP), R5
 	MOVW	new+8(FP), R6
@@ -207,6 +209,16 @@ TEXT runtime·timer_settime(SB),NOSPLIT,$0-20
 	MOVW	R2, ret+16(FP)
 	RET
 
+TEXT runtime·timer_settime64(SB),NOSPLIT,$0-20
+	MOVW	timerid+0(FP), R4
+	MOVW	flags+4(FP), R5
+	MOVW	new+8(FP), R6
+	MOVW	old+12(FP), R7
+	MOVW	$SYS_timer_settime64, R2
+	SYSCALL
+	MOVW	R2, ret+16(FP)
+	RET
+
 TEXT runtime·timer_delete(SB),NOSPLIT,$0-8
 	MOVW	timerid+0(FP), R4
 	MOVW	$SYS_timer_delete, R2

From 8a6c64f4fe726c956ea876cea0fed9494290130f Mon Sep 17 00:00:00 2001
From: qmuntal 
Date: Thu, 2 Oct 2025 15:12:30 +0200
Subject: [PATCH 215/229] syscall: use rawSyscall6 to call ptrace in
 forkAndExecInChild

On darwin and openbsd, the autogenerated ptrace wrapper is
nosplit because it is called from forkAndExecInChild.

This makes it difficult to modify and improve the underlying
syscall mechanism, as ptrace is almost over the nosplit limit.

We better call ptrace directly using rawSyscall6 in
forkAndExecInChild so that we can lift the ptrace nosplit
restriction to.

Doing so also fixes a long-standing inconsistency:
forkAndExecInChild is documented to only allow rawSyscall, but
the ptrace wrapper is using non-raw syscalls.

Updates #64113

Change-Id: Ibbbb218511561c1a5cb5b6d288a691f9738b14a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/708575
Reviewed-by: Michael Pratt 
Reviewed-by: David Chase 
LUCI-TryBot-Result: Go LUCI 
---
 src/syscall/exec_libc2.go               | 9 ++++++---
 src/syscall/mksyscall.pl                | 6 ------
 src/syscall/zsyscall_darwin_amd64.go    | 1 -
 src/syscall/zsyscall_darwin_arm64.go    | 1 -
 src/syscall/zsyscall_openbsd_386.go     | 1 -
 src/syscall/zsyscall_openbsd_amd64.go   | 1 -
 src/syscall/zsyscall_openbsd_arm.go     | 1 -
 src/syscall/zsyscall_openbsd_arm64.go   | 1 -
 src/syscall/zsyscall_openbsd_ppc64.go   | 1 -
 src/syscall/zsyscall_openbsd_riscv64.go | 1 -
 10 files changed, 6 insertions(+), 17 deletions(-)

diff --git a/src/syscall/exec_libc2.go b/src/syscall/exec_libc2.go
index a0579627a300bf..5de09dfe998070 100644
--- a/src/syscall/exec_libc2.go
+++ b/src/syscall/exec_libc2.go
@@ -59,7 +59,6 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
 		r1              uintptr
 		nextfd          int
 		i               int
-		err             error
 		pgrp            _C_int
 		cred            *Credential
 		ngroups, groups uintptr
@@ -99,8 +98,12 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
 
 	// Enable tracing if requested.
 	if sys.Ptrace {
-		if err = ptrace(PTRACE_TRACEME, 0, 0, 0); err != nil {
-			err1 = err.(Errno)
+		if runtime.GOOS == "ios" {
+			err1 = ENOSYS
+			goto childerror
+		}
+		_, _, err1 = rawSyscall6(abi.FuncPCABI0(libc_ptrace_trampoline), PTRACE_TRACEME, 0, 0, 0, 0, 0)
+		if err1 != 0 {
 			goto childerror
 		}
 	}
diff --git a/src/syscall/mksyscall.pl b/src/syscall/mksyscall.pl
index b46a3f9438bd87..6be94c9c44f065 100755
--- a/src/syscall/mksyscall.pl
+++ b/src/syscall/mksyscall.pl
@@ -141,12 +141,6 @@ ($)
 	# without reading the header.
 	$text .= "// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n\n";
 
-	if ((($darwin || ($openbsd && $libc)) && $func =~ /^ptrace(Ptr)?$/)) {
-		# The ptrace function is called from forkAndExecInChild where stack
-		# growth is forbidden.
-		$text .= "//go:nosplit\n"
-	}
-
 	# Go function header.
 	my $out_decl = @out ? sprintf(" (%s)", join(', ', @out)) : "";
 	$text .= sprintf "func %s(%s)%s {\n", $func, join(', ', @in), $out_decl;
diff --git a/src/syscall/zsyscall_darwin_amd64.go b/src/syscall/zsyscall_darwin_amd64.go
index 8812fb12cd19c6..fe4a264ed25c66 100644
--- a/src/syscall/zsyscall_darwin_amd64.go
+++ b/src/syscall/zsyscall_darwin_amd64.go
@@ -2011,7 +2011,6 @@ func libc_fstatat64_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-//go:nosplit
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	if runtime.GOOS == "ios" {
 		panic("unimplemented")
diff --git a/src/syscall/zsyscall_darwin_arm64.go b/src/syscall/zsyscall_darwin_arm64.go
index 22b096349d47b9..8fd7392d5b50f2 100644
--- a/src/syscall/zsyscall_darwin_arm64.go
+++ b/src/syscall/zsyscall_darwin_arm64.go
@@ -2011,7 +2011,6 @@ func libc_fstatat_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-//go:nosplit
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	if runtime.GOOS == "ios" {
 		panic("unimplemented")
diff --git a/src/syscall/zsyscall_openbsd_386.go b/src/syscall/zsyscall_openbsd_386.go
index c8cf7f231b1cb5..d914e19da0d8d3 100644
--- a/src/syscall/zsyscall_openbsd_386.go
+++ b/src/syscall/zsyscall_openbsd_386.go
@@ -1839,7 +1839,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-//go:nosplit
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	_, _, e1 := syscall6(abi.FuncPCABI0(libc_ptrace_trampoline), uintptr(request), uintptr(pid), uintptr(addr), uintptr(data), 0, 0)
 	if e1 != 0 {
diff --git a/src/syscall/zsyscall_openbsd_amd64.go b/src/syscall/zsyscall_openbsd_amd64.go
index 9188756a870a0a..5efe4cd8686f22 100644
--- a/src/syscall/zsyscall_openbsd_amd64.go
+++ b/src/syscall/zsyscall_openbsd_amd64.go
@@ -1839,7 +1839,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-//go:nosplit
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	_, _, e1 := syscall6(abi.FuncPCABI0(libc_ptrace_trampoline), uintptr(request), uintptr(pid), uintptr(addr), uintptr(data), 0, 0)
 	if e1 != 0 {
diff --git a/src/syscall/zsyscall_openbsd_arm.go b/src/syscall/zsyscall_openbsd_arm.go
index ecdfa636721893..db8ea482ef5983 100644
--- a/src/syscall/zsyscall_openbsd_arm.go
+++ b/src/syscall/zsyscall_openbsd_arm.go
@@ -1839,7 +1839,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-//go:nosplit
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	_, _, e1 := syscall6(abi.FuncPCABI0(libc_ptrace_trampoline), uintptr(request), uintptr(pid), uintptr(addr), uintptr(data), 0, 0)
 	if e1 != 0 {
diff --git a/src/syscall/zsyscall_openbsd_arm64.go b/src/syscall/zsyscall_openbsd_arm64.go
index d28d3c5e1ea71e..673791c8241471 100644
--- a/src/syscall/zsyscall_openbsd_arm64.go
+++ b/src/syscall/zsyscall_openbsd_arm64.go
@@ -1839,7 +1839,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-//go:nosplit
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	_, _, e1 := syscall6(abi.FuncPCABI0(libc_ptrace_trampoline), uintptr(request), uintptr(pid), uintptr(addr), uintptr(data), 0, 0)
 	if e1 != 0 {
diff --git a/src/syscall/zsyscall_openbsd_ppc64.go b/src/syscall/zsyscall_openbsd_ppc64.go
index 0e6828bcafdfeb..7e0dc88a4c155f 100644
--- a/src/syscall/zsyscall_openbsd_ppc64.go
+++ b/src/syscall/zsyscall_openbsd_ppc64.go
@@ -1839,7 +1839,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-//go:nosplit
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	_, _, e1 := syscall6(abi.FuncPCABI0(libc_ptrace_trampoline), uintptr(request), uintptr(pid), uintptr(addr), uintptr(data), 0, 0)
 	if e1 != 0 {
diff --git a/src/syscall/zsyscall_openbsd_riscv64.go b/src/syscall/zsyscall_openbsd_riscv64.go
index 920147074d091b..7b5a89ceac150d 100644
--- a/src/syscall/zsyscall_openbsd_riscv64.go
+++ b/src/syscall/zsyscall_openbsd_riscv64.go
@@ -1839,7 +1839,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-//go:nosplit
 func ptrace(request int, pid int, addr uintptr, data uintptr) (err error) {
 	_, _, e1 := syscall6(abi.FuncPCABI0(libc_ptrace_trampoline), uintptr(request), uintptr(pid), uintptr(addr), uintptr(data), 0, 0)
 	if e1 != 0 {

From 8f74f9daf4d2fe708cf28d0e2b9cce079fa19248 Mon Sep 17 00:00:00 2001
From: Nicolas Hillegeer 
Date: Tue, 21 Oct 2025 04:43:36 -0700
Subject: [PATCH 216/229] sync: re-enable race even when panicking

Not doing this can cause user code running after this panic (e.g.:
defers) to produce non-existing races.

Change-Id: Ia6aec88aaeee3b9c17e7b8019d697ffa88dfb492
Reviewed-on: https://go-review.googlesource.com/c/go/+/713460
Commit-Queue: Nicolas Hillegeer 
Reviewed-by: Michael Pratt 
Auto-Submit: Nicolas Hillegeer 
Reviewed-by: Michael Knyszek 
LUCI-TryBot-Result: Go LUCI 
---
 src/sync/waitgroup.go | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/sync/waitgroup.go b/src/sync/waitgroup.go
index 5b035aa3967ad3..195f839da417bd 100644
--- a/src/sync/waitgroup.go
+++ b/src/sync/waitgroup.go
@@ -204,13 +204,14 @@ func (wg *WaitGroup) Wait() {
 				}
 			}
 			runtime_SemacquireWaitGroup(&wg.sema, synctestDurable)
-			if wg.state.Load() != 0 {
-				panic("sync: WaitGroup is reused before previous Wait has returned")
-			}
+			isReset := wg.state.Load() != 0
 			if race.Enabled {
 				race.Enable()
 				race.Acquire(unsafe.Pointer(wg))
 			}
+			if isReset {
+				panic("sync: WaitGroup is reused before previous Wait has returned")
+			}
 			return
 		}
 	}

From c9c78c06ef4eac034c99efedfb4d23a3d51c1d6c Mon Sep 17 00:00:00 2001
From: Russ Cox 
Date: Thu, 16 Oct 2025 23:21:14 -0400
Subject: [PATCH 217/229] strconv: embed testdata in test

This makes it easier to run test binaries on remote machines.

Change-Id: I3e5bc6cf10272a6743fd5d16ab1089d46f53232c
Reviewed-on: https://go-review.googlesource.com/c/go/+/712660
Reviewed-by: David Chase 
LUCI-TryBot-Result: Go LUCI 
---
 src/strconv/fp_test.go | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/strconv/fp_test.go b/src/strconv/fp_test.go
index fd73958c97d29e..376e8f591c6dee 100644
--- a/src/strconv/fp_test.go
+++ b/src/strconv/fp_test.go
@@ -6,8 +6,8 @@ package strconv_test
 
 import (
 	"bufio"
+	_ "embed"
 	"fmt"
-	"os"
 	"strconv"
 	"strings"
 	"testing"
@@ -92,15 +92,11 @@ func myatof32(s string) (f float32, ok bool) {
 	return f1, true
 }
 
-func TestFp(t *testing.T) {
-	f, err := os.Open("testdata/testfp.txt")
-	if err != nil {
-		t.Fatal("testfp: open testdata/testfp.txt:", err)
-	}
-	defer f.Close()
-
-	s := bufio.NewScanner(f)
+//go:embed testdata/testfp.txt
+var testfp string
 
+func TestFp(t *testing.T) {
+	s := bufio.NewScanner(strings.NewReader(testfp))
 	for lineno := 1; s.Scan(); lineno++ {
 		line := s.Text()
 		if len(line) == 0 || line[0] == '#' {

From 261c561f5abc7cc6a9db62558b788580c306e69a Mon Sep 17 00:00:00 2001
From: Jes Cok 
Date: Tue, 21 Oct 2025 17:25:19 +0000
Subject: [PATCH 218/229] all: gofmt -w

Change-Id: Iae74ac910d9db035bb2b726b2128aac09f5b7aae
GitHub-Last-Rev: 7aab5fa8e76df87766e903d7a689ed257d986558
GitHub-Pull-Request: golang/go#75993
Reviewed-on: https://go-review.googlesource.com/c/go/+/713540
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Dmitri Shuralyov 
Auto-Submit: Dmitri Shuralyov 
Reviewed-by: Dmitri Shuralyov 
Reviewed-by: David Chase 
---
 src/cmd/cgo/internal/testout/out_test.go | 2 +-
 src/runtime/os_linux_settime32.go        | 4 ++--
 src/testing/fstest/testfs_test.go        | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/cmd/cgo/internal/testout/out_test.go b/src/cmd/cgo/internal/testout/out_test.go
index 81dfa365871372..e8ea5092a3562b 100644
--- a/src/cmd/cgo/internal/testout/out_test.go
+++ b/src/cmd/cgo/internal/testout/out_test.go
@@ -8,8 +8,8 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"internal/testenv"
 	"internal/goarch"
+	"internal/testenv"
 	"os"
 	"path/filepath"
 	"regexp"
diff --git a/src/runtime/os_linux_settime32.go b/src/runtime/os_linux_settime32.go
index 6df7f21dc9ce71..30f95455bfe2ad 100644
--- a/src/runtime/os_linux_settime32.go
+++ b/src/runtime/os_linux_settime32.go
@@ -27,8 +27,8 @@ func timer_settime(timerid int32, flags int32, new, old *itimerspec) int32 {
 		timer32bitOnly.Store(true)
 	}
 
-	var newts,oldts itimerspec32
-	var new32,old32 *itimerspec32
+	var newts, oldts itimerspec32
+	var new32, old32 *itimerspec32
 
 	if new != nil {
 		newts.it_interval.setNsec(new.it_interval.tv_sec*1e9 + new.it_interval.tv_nsec)
diff --git a/src/testing/fstest/testfs_test.go b/src/testing/fstest/testfs_test.go
index e3d7f1ab44d7b7..a0561b6dfc661c 100644
--- a/src/testing/fstest/testfs_test.go
+++ b/src/testing/fstest/testfs_test.go
@@ -105,7 +105,7 @@ func TestTestFSWrappedErrors(t *testing.T) {
 
 	// TestFS is expected to return a list of errors.
 	// Enforce that the list can be extracted for browsing.
-	type wrapper interface{
+	type wrapper interface {
 		error
 		Unwrap() []error
 	}

From 4a0115c886101717dfc6186a3296b69fc4415487 Mon Sep 17 00:00:00 2001
From: qmuntal 
Date: Tue, 26 Aug 2025 16:20:56 +0200
Subject: [PATCH 219/229] runtime,syscall: implement and use syscalln on darwin

All darwin syscall implementations can be consolidated into a
single syscalln function, as already happens on Windows.

This reduces duplication and allows moving some logic from
runtime to syscall.

Updates #699135

Cq-Include-Trybots: luci.golang.try:gotip-darwin-arm64-longtest,gotip-darwin-amd64-longtest,x_sys-gotip-darwin-arm64-longtest,x_sys-gotip-darwin-amd64-longtest
Change-Id: If5de80442b1d4a1123258401a3ae21695e7c8f6b
Reviewed-on: https://go-review.googlesource.com/c/go/+/699177
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: David Chase 
Reviewed-by: Michael Pratt 
---
 src/internal/trace/trace_test.go    |   3 +
 src/runtime/os_darwin.go            |   6 +
 src/runtime/sys_darwin.go           | 195 ++++++----------------------
 src/runtime/sys_darwin_amd64.s      | 161 +++++++++--------------
 src/runtime/sys_darwin_arm64.s      | 186 +++++++++++---------------
 src/syscall/syscall_darwin.go       | 128 +++++++++++++++++-
 src/syscall/syscall_darwin_amd64.go |   3 -
 src/syscall/syscall_darwin_arm64.go |   3 -
 8 files changed, 304 insertions(+), 381 deletions(-)

diff --git a/src/internal/trace/trace_test.go b/src/internal/trace/trace_test.go
index 25f671d440cb0c..479411548f22b2 100644
--- a/src/internal/trace/trace_test.go
+++ b/src/internal/trace/trace_test.go
@@ -448,6 +448,9 @@ func TestTraceStacks(t *testing.T) {
 					{"main.main.func11", 0},
 				}},
 			}...)
+			if runtime.GOOS == "darwin" {
+				want[len(want)-1].frames = append([]frame{{"syscall.syscall", 0}}, want[len(want)-1].frames...)
+			}
 		}
 		stackMatches := func(stk trace.Stack, frames []frame) bool {
 			for i, f := range slices.Collect(stk.Frames()) {
diff --git a/src/runtime/os_darwin.go b/src/runtime/os_darwin.go
index 0c7144e9d0fa82..c908809c81b2be 100644
--- a/src/runtime/os_darwin.go
+++ b/src/runtime/os_darwin.go
@@ -15,6 +15,11 @@ type mOS struct {
 	mutex       pthreadmutex
 	cond        pthreadcond
 	count       int
+
+	// address of errno variable for this thread.
+	// This is an optimization to avoid calling libc_error
+	// on every syscall_rawsyscalln.
+	errnoAddr *int32
 }
 
 func unimplemented(name string) {
@@ -330,6 +335,7 @@ func minit() {
 	}
 	minitSignalMask()
 	getg().m.procid = uint64(pthread_self())
+	libc_error_addr(&getg().m.errnoAddr)
 }
 
 // Called from dropm to undo the effect of an minit.
diff --git a/src/runtime/sys_darwin.go b/src/runtime/sys_darwin.go
index aa628021a05a39..48ad5afd8a009d 100644
--- a/src/runtime/sys_darwin.go
+++ b/src/runtime/sys_darwin.go
@@ -10,186 +10,65 @@ import (
 	"unsafe"
 )
 
-//go:nosplit
-func libcError() uintptr {
-	errPtr, _ := syscall(abi.FuncPCABI0(libc_error_trampoline), 0, 0, 0)
-	return errPtr
-}
 func libc_error_trampoline()
 
-// The X versions of syscall expect the libc call to return a 64-bit result.
-// Otherwise (the non-X version) expects a 32-bit result.
-// This distinction is required because an error is indicated by returning -1,
-// and we need to know whether to check 32 or 64 bits of the result.
-// (Some libc functions that return 32 bits put junk in the upper 32 bits of AX.)
-
-//go:nosplit
-func syscall(fn, a1, a2, a3 uintptr) (r1, r2 uintptr) {
-	args := struct{ fn, a1, a2, a3, r1, r2 uintptr }{fn, a1, a2, a3, r1, r2}
-	libcCall(unsafe.Pointer(abi.FuncPCABI0(syscall_trampoline)), unsafe.Pointer(&args))
-	return args.r1, args.r2
-}
-func syscall_trampoline()
-
-// golang.org/x/sys linknames syscall_syscall
-// (in addition to standard package syscall).
-// Do not remove or change the type signature.
-//
-//go:linkname syscall_syscall syscall.syscall
-//go:nosplit
-func syscall_syscall(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
-	entersyscall()
-	r1, r2, err = syscall_rawSyscall(fn, a1, a2, a3)
-	exitsyscall()
-	return r1, r2, err
-}
-
-//go:linkname syscall_syscallX syscall.syscallX
-//go:nosplit
-func syscall_syscallX(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
-	entersyscall()
-	r1, r2, err = syscall_rawSyscallX(fn, a1, a2, a3)
-	exitsyscall()
-	return r1, r2, err
-}
-
-//go:nosplit
-func syscall6(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr) {
-	args := struct{ fn, a1, a2, a3, a4, a5, a6, r1, r2 uintptr }{fn, a1, a2, a3, a4, a5, a6, r1, r2}
-	libcCall(unsafe.Pointer(abi.FuncPCABI0(syscall6_trampoline)), unsafe.Pointer(&args))
-	return args.r1, args.r2
-}
-func syscall6_trampoline()
-
-// golang.org/x/sys linknames syscall.syscall6
-// (in addition to standard package syscall).
-// Do not remove or change the type signature.
-//
-// syscall.syscall6 is meant for package syscall (and x/sys),
-// but widely used packages access it using linkname.
-// Notable members of the hall of shame include:
-//   - github.com/tetratelabs/wazero
-//
-// See go.dev/issue/67401.
+// libc_error_addr puts the libc error
+// address into addr.
 //
-//go:linkname syscall_syscall6 syscall.syscall6
 //go:nosplit
-func syscall_syscall6(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
-	entersyscall()
-	r1, r2, err = syscall_rawSyscall6(fn, a1, a2, a3, a4, a5, a6)
-	exitsyscall()
-	return r1, r2, err
-}
-
-//go:linkname syscall_syscall6X syscall.syscall6X
-//go:nosplit
-func syscall_syscall6X(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
-	entersyscall()
-	r1, r2, err = syscall_rawSyscall6X(fn, a1, a2, a3, a4, a5, a6)
-	exitsyscall()
-	return r1, r2, err
+//go:cgo_unsafe_args
+func libc_error_addr(addr **int32) {
+	libcCall(unsafe.Pointer(abi.FuncPCABI0(libc_error_trampoline)), unsafe.Pointer(&addr))
 }
 
-//go:nosplit
-func syscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr) {
-	args := struct{ fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, r1, r2 uintptr }{fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, r1, r2}
-	libcCall(unsafe.Pointer(abi.FuncPCABI0(syscall9_trampoline)), unsafe.Pointer(&args))
-	return args.r1, args.r2
+// libcCallInfo is a structure used to pass parameters to the system call.
+type libcCallInfo struct {
+	fn     uintptr
+	n      uintptr // number of parameters
+	args   uintptr // parameters
+	r1, r2 uintptr // return values
 }
-func syscall9_trampoline()
 
-// golang.org/x/sys linknames syscall.syscall9
-// (in addition to standard package syscall).
-// Do not remove or change the type signature.
+// syscall_syscalln is a wrapper around the libc call with variable arguments.
 //
-//go:linkname syscall_syscall9 syscall.syscall9
+//go:linkname syscall_syscalln syscall.syscalln
 //go:nosplit
-func syscall_syscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) {
+//go:uintptrkeepalive
+func syscall_syscalln(fn uintptr, args ...uintptr) (r1, r2, err uintptr) {
 	entersyscall()
-	r1, r2, err = syscall_rawSyscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9)
+	r1, r2, err = syscall_rawsyscalln(fn, args...)
 	exitsyscall()
 	return r1, r2, err
 }
 
-// golang.org/x/sys linknames syscall.syscallPtr
-// (in addition to standard package syscall).
-// Do not remove or change the type signature.
+// syscall_rawsyscalln is a wrapper around the libc call with variable arguments.
+// The scheduler is not notified about the system call.
+// The syscall is executed on the current goroutine thread rather than on a
+// dedicated syscall thread.
 //
-//go:linkname syscall_syscallPtr syscall.syscallPtr
+//go:linkname syscall_rawsyscalln syscall.rawsyscalln
 //go:nosplit
-func syscall_syscallPtr(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
-	entersyscall()
-	r1, r2, err = syscall_rawSyscallPtr(fn, a1, a2, a3)
-	exitsyscall()
-	return r1, r2, err
-}
-
-// golang.org/x/sys linknames syscall_rawSyscall
-// (in addition to standard package syscall).
-// Do not remove or change the type signature.
-//
-//go:linkname syscall_rawSyscall syscall.rawSyscall
-//go:nosplit
-func syscall_rawSyscall(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
-	r1, r2 = syscall(fn, a1, a2, a3)
-	// Check if r1 low 32 bits is -1, indicating an error.
-	if int32(r1) == -1 {
-		err = libcError()
+//go:uintptrkeepalive
+func syscall_rawsyscalln(fn uintptr, args ...uintptr) (r1, r2, err uintptr) {
+	c := &libcCallInfo{
+		fn: fn,
+		n:  uintptr(len(args)),
 	}
-	return r1, r2, err
-}
-
-//go:nosplit
-func syscall_rawSyscallX(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
-	r1, r2 = syscall(fn, a1, a2, a3)
-	if r1 == ^uintptr(0) {
-		err = libcError()
+	if c.n != 0 {
+		c.args = uintptr(noescape(unsafe.Pointer(&args[0])))
 	}
-	return r1, r2, err
-}
-
-//go:nosplit
-func syscall_rawSyscallPtr(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
-	r1, r2 = syscall(fn, a1, a2, a3)
-	if r1 == 0 {
-		err = libcError()
-	}
-	return r1, r2, err
-}
-
-// golang.org/x/sys linknames syscall_rawSyscall6
-// (in addition to standard package syscall).
-// Do not remove or change the type signature.
-//
-//go:linkname syscall_rawSyscall6 syscall.rawSyscall6
-//go:nosplit
-func syscall_rawSyscall6(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
-	r1, r2 = syscall6(fn, a1, a2, a3, a4, a5, a6)
-	// Check if r1 low 32 bits is -1, indicating an error.
-	if int32(r1) == -1 {
-		err = libcError()
-	}
-	return r1, r2, err
-}
-
-//go:nosplit
-func syscall_rawSyscall6X(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
-	r1, r2 = syscall6(fn, a1, a2, a3, a4, a5, a6)
-	if r1 == ^uintptr(0) {
-		err = libcError()
+	libcCall(unsafe.Pointer(abi.FuncPCABI0(syscallN_trampoline)), unsafe.Pointer(c))
+	if gp := getg(); gp != nil && gp.m != nil && gp.m.errnoAddr != nil {
+		err = uintptr(*gp.m.errnoAddr)
+	} else {
+		var errnoAddr *int32
+		libc_error_addr(&errnoAddr)
+		err = uintptr(*errnoAddr)
 	}
-	return r1, r2, err
+	return c.r1, c.r2, err
 }
 
-//go:nosplit
-func syscall_rawSyscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, err uintptr) {
-	r1, r2 = syscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9)
-	// Check if r1 low 32 bits is -1, indicating an error.
-	if int32(r1) == -1 {
-		err = libcError()
-	}
-	return r1, r2, err
-}
+func syscallN_trampoline()
 
 // crypto_x509_syscall is used in crypto/x509/internal/macos to call into Security.framework and CF.
 
diff --git a/src/runtime/sys_darwin_amd64.s b/src/runtime/sys_darwin_amd64.s
index e7462579677d23..99d67a9cfd2d6e 100644
--- a/src/runtime/sys_darwin_amd64.s
+++ b/src/runtime/sys_darwin_amd64.s
@@ -506,118 +506,73 @@ TEXT runtime·arc4random_buf_trampoline(SB),NOSPLIT,$0
 	CALL	libc_arc4random_buf(SB)
 	RET
 
-// syscall_trampoline calls a function in libc on behalf of the syscall package.
-// syscall_trampoline takes a pointer to a struct like:
-// struct {
-//	fn    uintptr
-//	a1    uintptr
-//	a2    uintptr
-//	a3    uintptr
-//	r1    uintptr
-//	r2    uintptr
-// }
-// syscall_trampoline must be called on the g0 stack with the
-// C calling convention (use libcCall).
-TEXT runtime·syscall_trampoline(SB),NOSPLIT,$16
-	MOVQ	(0*8)(DI), CX // fn
-	MOVQ	(2*8)(DI), SI // a2
-	MOVQ	(3*8)(DI), DX // a3
-	MOVQ	DI, (SP)
-	MOVQ	(1*8)(DI), DI // a1
-	XORL	AX, AX	      // vararg: say "no float args"
-
-	CALL	CX
-
-	MOVQ	(SP), DI
-	MOVQ	AX, (4*8)(DI) // r1
-	MOVQ	DX, (5*8)(DI) // r2
-
-	XORL	AX, AX        // no error (it's ignored anyway)
-	RET
 
-// syscall6_trampoline calls a function in libc on behalf of the syscall package.
-// syscall6_trampoline takes a pointer to a struct like:
-// struct {
-//	fn    uintptr
-//	a1    uintptr
-//	a2    uintptr
-//	a3    uintptr
-//	a4    uintptr
-//	a5    uintptr
-//	a6    uintptr
-//	r1    uintptr
-//	r2    uintptr
-// }
-// syscall6_trampoline must be called on the g0 stack with the
-// C calling convention (use libcCall).
-TEXT runtime·syscall6_trampoline(SB),NOSPLIT,$16
-	MOVQ	(0*8)(DI), R11// fn
-	MOVQ	(2*8)(DI), SI // a2
-	MOVQ	(3*8)(DI), DX // a3
-	MOVQ	(4*8)(DI), CX // a4
-	MOVQ	(5*8)(DI), R8 // a5
-	MOVQ	(6*8)(DI), R9 // a6
-	MOVQ	DI, (SP)
-	MOVQ	(1*8)(DI), DI // a1
-	XORL	AX, AX	      // vararg: say "no float args"
+TEXT runtime·syscallN_trampoline(SB),NOSPLIT,$0
+	// store argument and original SP in a callee-saved register
+	MOVQ	DI, R13
+	MOVQ	SP, R14
+
+	MOVQ	libcCallInfo_fn(R13), R11
+	MOVQ	libcCallInfo_n(R13), CX
+	MOVQ	libcCallInfo_args(R13), R10
+
+	// Fast version, do not store args on the stack.
+	CMPL	CX, $0; JE _0args
+	CMPL	CX, $1; JE _1args
+	CMPL	CX, $2; JE _2args
+	CMPL	CX, $3; JE _3args
+	CMPL	CX, $4; JE _4args
+	CMPL	CX, $5; JE _5args
+	CMPL	CX, $6; JE _6args
+
+	// Reserve stack space for remaining args
+	MOVQ	CX, R12
+	SUBQ	$6, R12
+	ADDQ	$1, R12	// make even number of words for stack alignment
+	ANDQ	$~1, R12
+	SHLQ	$3, R12
+	SUBQ	R12, SP
+
+	// Copy args to the stack.
+	// CX: count of stack arguments (n-6)
+	// SI: &args[6]
+	// DI: copy of RSP
+	SUBQ	$6, CX
+	MOVQ	R10, SI
+	ADDQ	$(8*6), SI
+	MOVQ	SP, DI
+	CLD
+	REP; MOVSQ
+
+_6args:
+	MOVQ	(5*8)(R10), R9
+_5args:
+	MOVQ	(4*8)(R10), R8
+_4args:
+	MOVQ	(3*8)(R10), CX
+_3args:
+	MOVQ	(2*8)(R10), DX
+_2args:
+	MOVQ	(1*8)(R10), SI
+_1args:
+	MOVQ	(0*8)(R10), DI
+_0args:
+
+	XORL	AX, AX	// vararg: say "no float args"
 
 	CALL	R11
 
-	MOVQ	(SP), DI
-	MOVQ	AX, (7*8)(DI) // r1
-	MOVQ	DX, (8*8)(DI) // r2
+	MOVQ	R14, SP	// free stack space
 
-	XORL	AX, AX        // no error (it's ignored anyway)
-	RET
-
-// syscall9_trampoline calls a function in libc on behalf of the syscall package.
-// syscall9_trampoline takes a pointer to a struct like:
-// struct {
-//	fn    uintptr
-//	a1    uintptr
-//	a2    uintptr
-//	a3    uintptr
-//	a4    uintptr
-//	a5    uintptr
-//	a6    uintptr
-//	a7    uintptr
-//	a8    uintptr
-//	a9    uintptr
-//	r1    uintptr
-//	r2    uintptr
-//	err   uintptr
-// }
-// syscall9_trampoline must be called on the g0 stack with the
-// C calling convention (use libcCall).
-TEXT runtime·syscall9_trampoline(SB),NOSPLIT,$32
-	MOVQ	(0*8)(DI), R13// fn
-	MOVQ	(2*8)(DI), SI // a2
-	MOVQ	(3*8)(DI), DX // a3
-	MOVQ	(4*8)(DI), CX // a4
-	MOVQ	(5*8)(DI), R8 // a5
-	MOVQ	(6*8)(DI), R9 // a6
-	MOVQ	(7*8)(DI), R10 // a7
-	MOVQ	R10, 0(SP)
-	MOVQ	(8*8)(DI), R11 // a8
-	MOVQ	R11, 8(SP)
-	MOVQ	(9*8)(DI), R12 // a9
-	MOVQ	R12, 16(SP)
-	MOVQ	DI, 24(SP)
-	MOVQ	(1*8)(DI), DI // a1
-	XORL	AX, AX	      // vararg: say "no float args"
-
-	CALL	R13
-
-	MOVQ	24(SP), DI
-	MOVQ	AX, (10*8)(DI) // r1
-	MOVQ	DX, (11*8)(DI) // r2
-
-	XORL	AX, AX        // no error (it's ignored anyway)
+	// Return result.
+	MOVQ	AX, libcCallInfo_r1(R13)
+	MOVQ	DX, libcCallInfo_r2(R13)
 	RET
 
 TEXT runtime·libc_error_trampoline(SB),NOSPLIT,$0
+	MOVQ	0(DI), R14
 	CALL	libc_error(SB)
-	MOVLQSX	(AX), AX
+	MOVQ	AX, (R14)
 	RET
 
 // syscall_x509 is for crypto/x509. It is like syscall6 but does not check for errors,
diff --git a/src/runtime/sys_darwin_arm64.s b/src/runtime/sys_darwin_arm64.s
index adbb2adafe94f2..7bbe965c1583f8 100644
--- a/src/runtime/sys_darwin_arm64.s
+++ b/src/runtime/sys_darwin_arm64.s
@@ -481,128 +481,98 @@ TEXT runtime·arc4random_buf_trampoline(SB),NOSPLIT,$0
 	BL	libc_arc4random_buf(SB)
 	RET
 
-// syscall_trampoline calls a function in libc on behalf of the syscall package.
-// syscall_trampoline takes a pointer to a struct like:
-// struct {
-//	fn    uintptr
-//	a1    uintptr
-//	a2    uintptr
-//	a3    uintptr
-//	r1    uintptr
-//	r2    uintptr
-// }
-// syscall_trampoline must be called on the g0 stack with the
-// C calling convention (use libcCall).
-TEXT runtime·syscall_trampoline(SB),NOSPLIT,$0
-	SUB	$16, RSP // push structure pointer
-	MOVD	R0, 8(RSP)
-
-	MOVD	0(R0), R12	// fn
-	MOVD	16(R0), R1	// a2
-	MOVD	24(R0), R2	// a3
-	MOVD	8(R0), R0	// a1
+TEXT runtime·syscallN_trampoline(SB),NOSPLIT,$16
+	STP	(R19, R20), 16(RSP)	// save old R19, R20
+	MOVD	R0, R19	// save struct pointer
+	MOVD	RSP, R20	// save stack pointer
+	SUB	$16, RSP	// reserve 16 bytes for sp-8 where fp may be saved.
+
+	MOVD	libcCallInfo_args(R19), R12
+	// Do we have more than 8 arguments?
+	MOVD	libcCallInfo_n(R19), R0
+	CMP	$0, R0; BEQ _0args
+	CMP	$1, R0; BEQ _1args
+	CMP	$2, R0; BEQ _2args
+	CMP	$3, R0; BEQ _3args
+	CMP	$4, R0; BEQ _4args
+	CMP	$5, R0; BEQ _5args
+	CMP	$6, R0; BEQ _6args
+	CMP	$7, R0; BEQ _7args
+	CMP	$8, R0; BEQ _8args
+
+	// Reserve stack space for remaining args
+	SUB	$8, R0, R2
+	ADD	$1, R2, R3	// make even number of words for stack alignment
+	AND	$~1, R3
+	LSL	$3, R3
+	SUB	R3, RSP
+
+	// R4: size of stack arguments (n-8)*8
+	// R5: &args[8]
+	// R6: loop counter, from 0 to (n-8)*8
+	// R7: scratch
+	// R8: copy of RSP - (R2)(RSP) assembles as (R2)(ZR)
+	SUB	$8, R0, R4
+	LSL	$3, R4
+	ADD	$(8*8), R12, R5
+	MOVD	$0, R6
+	MOVD	RSP, R8
+stackargs:
+	MOVD	(R6)(R5), R7
+	MOVD	R7, (R6)(R8)
+	ADD	$8, R6
+	CMP	R6, R4
+	BNE	stackargs
+
+_8args:
+	MOVD	(7*8)(R12), R7
+_7args:
+	MOVD	(6*8)(R12), R6
+_6args:
+	MOVD	(5*8)(R12), R5
+_5args:
+	MOVD	(4*8)(R12), R4
+_4args:
+	MOVD	(3*8)(R12), R3
+_3args:
+	MOVD	(2*8)(R12), R2
+_2args:
+	MOVD	(1*8)(R12), R1
+_1args:
+	MOVD	(0*8)(R12), R0
+_0args:
 
 	// If fn is declared as vararg, we have to pass the vararg arguments on the stack.
 	// (Because ios decided not to adhere to the standard arm64 calling convention, sigh...)
-	// The only libSystem calls we support that are vararg are open, fcntl, and ioctl,
-	// which are all of the form fn(x, y, ...). So we just need to put the 3rd arg
-	// on the stack as well.
+	// The only libSystem calls we support with vararg are open, fcntl, ioctl,
+	// which are all of the form fn(x, y, ...), and openat, which is of the form fn(x, y, z, ...).
+	// So we just need to put the  3rd and the 4th arg on the stack as well.
+	// Note that historically openat has been called with syscall6, so we need to handle that case too.
 	// If we ever have other vararg libSystem calls, we might need to handle more cases.
+	MOVD	libcCallInfo_n(R19), R12
+	CMP	$3, R12; BNE 2(PC);
 	MOVD	R2, (RSP)
-
-	BL	(R12)
-
-	MOVD	8(RSP), R2	// pop structure pointer
-	ADD	$16, RSP
-	MOVD	R0, 32(R2)	// save r1
-	MOVD	R1, 40(R2)	// save r2
-	RET
-
-// syscall6_trampoline calls a function in libc on behalf of the syscall package.
-// syscall6_trampoline takes a pointer to a struct like:
-// struct {
-//	fn    uintptr
-//	a1    uintptr
-//	a2    uintptr
-//	a3    uintptr
-//	a4    uintptr
-//	a5    uintptr
-//	a6    uintptr
-//	r1    uintptr
-//	r2    uintptr
-// }
-// syscall6_trampoline must be called on the g0 stack with the
-// C calling convention (use libcCall).
-TEXT runtime·syscall6_trampoline(SB),NOSPLIT,$0
-	SUB	$16, RSP	// push structure pointer
-	MOVD	R0, 8(RSP)
-
-	MOVD	0(R0), R12	// fn
-	MOVD	16(R0), R1	// a2
-	MOVD	24(R0), R2	// a3
-	MOVD	32(R0), R3	// a4
-	MOVD	40(R0), R4	// a5
-	MOVD	48(R0), R5	// a6
-	MOVD	8(R0), R0	// a1
-
-	// If fn is declared as vararg, we have to pass the vararg arguments on the stack.
-	// See syscall_trampoline above. The only function this applies to is openat, for which the 4th
-	// arg must be on the stack.
+	CMP $4, R12; BNE 2(PC);
+	MOVD	R3, (RSP)
+	CMP $6, R12; BNE 2(PC);
 	MOVD	R3, (RSP)
 
+	MOVD	libcCallInfo_fn(R19), R12
 	BL	(R12)
 
-	MOVD	8(RSP), R2	// pop structure pointer
-	ADD	$16, RSP
-	MOVD	R0, 56(R2)	// save r1
-	MOVD	R1, 64(R2)	// save r2
-	RET
-
-// syscall9_trampoline calls a function in libc on behalf of the syscall package.
-// syscall9_trampoline takes a pointer to a struct like:
-// struct {
-//	fn    uintptr
-//	a1    uintptr
-//	a2    uintptr
-//	a3    uintptr
-//	a4    uintptr
-//	a5    uintptr
-//	a6    uintptr
-//	a7    uintptr
-//	a8    uintptr
-//	a9    uintptr
-//	r1    uintptr
-//	r2    uintptr
-// }
-// syscall9_trampoline must be called on the g0 stack with the
-// C calling convention (use libcCall).
-TEXT runtime·syscall9_trampoline(SB),NOSPLIT,$0
-	SUB	$16, RSP	// push structure pointer
-	MOVD	R0, 8(RSP)
+	MOVD	R20, RSP	// free stack space
 
-	MOVD	0(R0), R12	// fn
-	MOVD	16(R0), R1	// a2
-	MOVD	24(R0), R2	// a3
-	MOVD	32(R0), R3	// a4
-	MOVD	40(R0), R4	// a5
-	MOVD	48(R0), R5	// a6
-	MOVD	56(R0), R6	// a7
-	MOVD	64(R0), R7	// a8
-	MOVD	72(R0), R8	// a9
-	MOVD	R8, 0(RSP)	// the 9th arg and onwards must be passed on the stack
-	MOVD	8(R0), R0	// a1
-
-	BL	(R12)
+	MOVD	R0, libcCallInfo_r1(R19)
+	MOVD	R1, libcCallInfo_r2(R19)
 
-	MOVD	8(RSP), R2	// pop structure pointer
-	ADD	$16, RSP
-	MOVD	R0, 80(R2)	// save r1
-	MOVD	R1, 88(R2)	// save r2
-	RET
+	// Restore callee-saved registers.
+	LDP	16(RSP), (R19, R20)
+    RET
 
 TEXT runtime·libc_error_trampoline(SB),NOSPLIT,$0
+	MOVD	0(R0), R20
 	BL	libc_error(SB)
-	MOVW	(R0), R0
+	MOVD	R0, (R20)
 	RET
 
 // syscall_x509 is for crypto/x509. It is like syscall6 but does not check for errors,
diff --git a/src/syscall/syscall_darwin.go b/src/syscall/syscall_darwin.go
index 7b4f0d4fb74c48..ca76cc2962b098 100644
--- a/src/syscall/syscall_darwin.go
+++ b/src/syscall/syscall_darwin.go
@@ -323,10 +323,126 @@ func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) {
 	return n, nil
 }
 
+// errno return e if int32(r) is -1, else it returns 0.
+//
+//go:nosplit
+func errno(r uintptr, e Errno) Errno {
+	if int32(r) == -1 {
+		return e
+	}
+	return 0
+}
+
+// errnoX return e if r is -1, else it returns 0.
+//
+//go:nosplit
+func errnoX(r uintptr, e Errno) Errno {
+	if r == ^uintptr(0) {
+		return e
+	}
+	return 0
+}
+
+// errnoPtr return e if r is 0, else it returns 0.
+//
+//go:nosplit
+func errnoPtr(r uintptr, e Errno) Errno {
+	if r == 0 {
+		return e
+	}
+	return 0
+}
+
+//go:cgo_import_dynamic libc_error __error "/usr/lib/libSystem.B.dylib"
+
+// golang.org/x/sys linknames the following syscalls.
+// Do not remove or change the type signature.
+
+//go:linkname syscall
+//go:nosplit
+//go:uintptrkeepalive
+func syscall(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, err = syscalln(fn, a1, a2, a3)
+	return r1, r2, errno(r1, err)
+}
+
+//go:linkname syscallX
+//go:nosplit
+//go:uintptrkeepalive
+func syscallX(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, err = syscalln(fn, a1, a2, a3)
+	return r1, r2, errnoX(r1, err)
+}
+
+// syscall.syscall6 is meant for package syscall (and x/sys),
+// but widely used packages access it using linkname.
+// Notable members of the hall of shame include:
+//   - github.com/tetratelabs/wazero
+//
+// See go.dev/issue/67401.
+//
+//go:linkname syscall6
+//go:nosplit
+//go:uintptrkeepalive
+func syscall6(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, err = syscalln(fn, a1, a2, a3, a4, a5, a6)
+	return r1, r2, errno(r1, err)
+}
+
+//go:linkname syscall6X
+//go:nosplit
+//go:uintptrkeepalive
+func syscall6X(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, err = syscalln(fn, a1, a2, a3, a4, a5, a6)
+	return r1, r2, errnoX(r1, err)
+}
+
+// syscall9 is used in [internal/syscall/unix].
+//
+//go:linkname syscall9
+//go:nosplit
+//go:uintptrkeepalive
+func syscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, err = syscalln(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9)
+	return r1, r2, errno(r1, err)
+}
+
+//go:linkname rawSyscall
+//go:nosplit
+//go:uintptrkeepalive
+func rawSyscall(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, err = rawsyscalln(fn, a1, a2, a3)
+	return r1, r2, errno(r1, err)
+}
+
+//go:linkname rawSyscall6
+//go:nosplit
+//go:uintptrkeepalive
+func rawSyscall6(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, err = rawsyscalln(fn, a1, a2, a3, a4, a5, a6)
+	return r1, r2, errno(r1, err)
+}
+
+//go:linkname rawSyscall9
+//go:nosplit
+//go:uintptrkeepalive
+func rawSyscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, err = rawsyscalln(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9)
+	return r1, r2, errno(r1, err)
+}
+
+//go:linkname syscallPtr
+//go:nosplit
+//go:uintptrkeepalive
+func syscallPtr(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno) {
+	r1, r2, e1 := syscalln(fn, a1, a2, a3)
+	return r1, r2, errnoPtr(r1, e1)
+}
+
 // Implemented in the runtime package (runtime/sys_darwin.go)
-func syscall(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
-func syscall6(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
-func syscall6X(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
-func rawSyscall(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
-func rawSyscall6(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
-func syscallPtr(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
+
+//go:noescape
+func syscalln(fn uintptr, args ...uintptr) (r1, r2 uintptr, err Errno)
+
+//go:noescape
+func rawsyscalln(fn uintptr, args ...uintptr) (r1, r2 uintptr, err Errno)
diff --git a/src/syscall/syscall_darwin_amd64.go b/src/syscall/syscall_darwin_amd64.go
index 64e54ad73081af..d4de4c25a43aa8 100644
--- a/src/syscall/syscall_darwin_amd64.go
+++ b/src/syscall/syscall_darwin_amd64.go
@@ -61,7 +61,4 @@ func libc_sendfile_trampoline()
 
 //go:cgo_import_dynamic libc_sendfile sendfile "/usr/lib/libSystem.B.dylib"
 
-// Implemented in the runtime package (runtime/sys_darwin_64.go)
-func syscallX(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
-
 func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno)
diff --git a/src/syscall/syscall_darwin_arm64.go b/src/syscall/syscall_darwin_arm64.go
index 913c7483746864..4a3dce8088245a 100644
--- a/src/syscall/syscall_darwin_arm64.go
+++ b/src/syscall/syscall_darwin_arm64.go
@@ -61,7 +61,4 @@ func libc_sendfile_trampoline()
 
 //go:cgo_import_dynamic libc_sendfile sendfile "/usr/lib/libSystem.B.dylib"
 
-// Implemented in the runtime package (runtime/sys_darwin_64.go)
-func syscallX(fn, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
-
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno) // sic

From 39fd61ddb0b5987749979bc7e453cf2a575c9392 Mon Sep 17 00:00:00 2001
From: Mark Freeman 
Date: Fri, 17 Oct 2025 13:16:34 -0400
Subject: [PATCH 220/229] go/types, types2: guard Named.underlying with
 Named.mu

It appears that CL 695977 introduced a data race on Named.underlying.
This fixes that race by specifying a new namedState called underlying,
which, perhaps unsurprisingly, signals that Named.underlying is populated.

Unfortunately, the underlying namedState is independent of the complete
namedState (unsurprising since methods and the underlying type are not related).

Hence, they cannot be ordered and thus do not fit the current integer-based
state representation. To account for combinations of states, we introduce a
bit set representation for namedState instead. The namedState field is also
renamed to stateMask to reflect this new representation.

Methods that operate on the stateMask are adjusted and exposition is added
throughout.

Fixes #75963

Change-Id: Icfa188ea2fa7916804c06f80668e99176bf4e978
Reviewed-on: https://go-review.googlesource.com/c/go/+/712720
Auto-Submit: Mark Freeman 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Robert Griesemer 
---
 src/cmd/compile/internal/types2/named.go | 137 +++++++++++++++--------
 src/go/types/named.go                    | 137 +++++++++++++++--------
 2 files changed, 184 insertions(+), 90 deletions(-)

diff --git a/src/cmd/compile/internal/types2/named.go b/src/cmd/compile/internal/types2/named.go
index 80247e63ded8c8..8f3249e44ed99e 100644
--- a/src/cmd/compile/internal/types2/named.go
+++ b/src/cmd/compile/internal/types2/named.go
@@ -47,10 +47,8 @@ import (
 // soon.
 //
 // We achieve this by tracking state with an atomic state variable, and
-// guarding potentially concurrent calculations with a mutex. At any point in
-// time this state variable determines which data on N may be accessed. As
-// state monotonically progresses, any data available at state M may be
-// accessed without acquiring the mutex at state N, provided N >= M.
+// guarding potentially concurrent calculations with a mutex. See [stateMask]
+// for details.
 //
 // GLOSSARY: Here are a few terms used in this file to describe Named types:
 //  - We say that a Named type is "instantiated" if it has been constructed by
@@ -111,13 +109,13 @@ type Named struct {
 	allowNilRHS        bool // same as below, as well as briefly during checking of a type declaration
 	allowNilUnderlying bool // may be true from creation via [NewNamed] until [Named.SetUnderlying]
 
-	underlying Type      // underlying type, or nil
-	inst       *instance // information for instantiated types; nil otherwise
+	inst *instance // information for instantiated types; nil otherwise
 
-	mu      sync.Mutex     // guards all fields below
-	state_  uint32         // the current state of this type; must only be accessed atomically
-	fromRHS Type           // the declaration RHS this type is derived from
-	tparams *TypeParamList // type parameters, or nil
+	mu         sync.Mutex     // guards all fields below
+	state_     uint32         // the current state of this type; must only be accessed atomically or when mu is held
+	fromRHS    Type           // the declaration RHS this type is derived from
+	tparams    *TypeParamList // type parameters, or nil
+	underlying Type           // underlying type, or nil
 
 	// methods declared for this type (not the method set of this type)
 	// Signatures are type-checked lazily.
@@ -139,15 +137,43 @@ type instance struct {
 	ctxt            *Context  // local Context; set to nil after full expansion
 }
 
-// namedState represents the possible states that a named type may assume.
-type namedState uint32
+// stateMask represents each state in the lifecycle of a named type.
+//
+// Each named type begins in the unresolved state. A named type may transition to a new state
+// according to the below diagram:
+//
+//	unresolved
+//	loaded
+//	resolved
+//	└── complete
+//	└── underlying
+//
+// That is, descent down the tree is mostly linear (unresolved through resolved), except upon
+// reaching the leaves (complete and underlying). A type may occupy any combination of the
+// leaf states at once (they are independent states).
+//
+// To represent this independence, the set of active states is represented with a bit set. State
+// transitions are monotonic. Once a state bit is set, it remains set.
+//
+// The above constraints significantly narrow the possible bit sets for a named type. With bits
+// set left-to-right, they are:
+//
+//	0000 | unresolved
+//	1000 | loaded
+//	1100 | resolved, which implies loaded
+//	1110 | completed, which implies resolved (which in turn implies loaded)
+//	1101 | underlying, which implies resolved ...
+//	1111 | both completed and underlying which implies resolved ...
+//
+// To read the state of a named type, use [Named.stateHas]; to write, use [Named.setState].
+type stateMask uint32
 
-// Note: the order of states is relevant
 const (
-	unresolved namedState = iota // type parameters, RHS, underlying, and methods might be unavailable
-	resolved                     // resolve has run; methods might be unexpanded (for instances)
-	loaded                       // loader has run; constraints might be unexpanded (for generic types)
-	complete                     // all data is known
+	// before resolved, type parameters, RHS, underlying, and methods might be unavailable
+	resolved   stateMask = 1 << iota // methods might be unexpanded (for instances)
+	complete                         // methods are all expanded (for instances)
+	loaded                           // methods are available, but constraints might be unexpanded (for generic types)
+	underlying                       // underlying type is available
 )
 
 // NewNamed returns a new named type for the given type name, underlying type, and associated methods.
@@ -188,7 +214,7 @@ func NewNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
 // All others:
 // Effectively, nothing happens.
 func (n *Named) resolve() *Named {
-	if n.state() >= resolved { // avoid locking below
+	if n.stateHas(resolved | loaded) { // avoid locking below
 		return n
 	}
 
@@ -197,10 +223,14 @@ func (n *Named) resolve() *Named {
 	n.mu.Lock()
 	defer n.mu.Unlock()
 
-	if n.state() >= resolved {
+	// only atomic for consistency; we are holding the mutex
+	if n.stateHas(resolved | loaded) {
 		return n
 	}
 
+	// underlying comes after resolving, do not set it
+	defer (func() { assert(!n.stateHas(underlying)) })()
+
 	if n.inst != nil {
 		assert(n.fromRHS == nil) // instantiated types are not declared types
 		assert(n.loader == nil)  // cannot import an instantiation
@@ -212,7 +242,7 @@ func (n *Named) resolve() *Named {
 		n.tparams = orig.tparams
 
 		if len(orig.methods) == 0 {
-			n.setState(complete) // nothing further to do
+			n.setState(resolved | complete) // nothing further to do
 			n.inst.ctxt = nil
 		} else {
 			n.setState(resolved)
@@ -239,27 +269,24 @@ func (n *Named) resolve() *Named {
 		n.methods = methods
 
 		n.setState(loaded) // avoid deadlock calling delayed functions
-
 		for _, f := range delayed {
 			f()
 		}
 	}
 
-	assert(n.fromRHS != nil || n.allowNilRHS)
-	assert(n.underlying == nil) // underlying comes after resolving
-	n.setState(complete)
+	n.setState(resolved | complete)
 	return n
 }
 
-// state atomically accesses the current state of the receiver.
-func (n *Named) state() namedState {
-	return namedState(atomic.LoadUint32(&n.state_))
+// stateHas atomically determines whether the current state includes any active bit in sm.
+func (n *Named) stateHas(sm stateMask) bool {
+	return atomic.LoadUint32(&n.state_)&uint32(sm) != 0
 }
 
-// setState atomically stores the given state for n.
+// setState atomically sets the current state to include each active bit in sm.
 // Must only be called while holding n.mu.
-func (n *Named) setState(state namedState) {
-	atomic.StoreUint32(&n.state_, uint32(state))
+func (n *Named) setState(sm stateMask) {
+	atomic.OrUint32(&n.state_, uint32(sm))
 }
 
 // newNamed is like NewNamed but with a *Checker receiver.
@@ -369,7 +396,7 @@ func (t *Named) NumMethods() int {
 func (t *Named) Method(i int) *Func {
 	t.resolve()
 
-	if t.state() >= complete {
+	if t.stateHas(complete) {
 		return t.methods[i]
 	}
 
@@ -461,20 +488,25 @@ func (t *Named) expandMethod(i int) *Func {
 
 // SetUnderlying sets the underlying type and marks t as complete.
 // t must not have type arguments.
-func (t *Named) SetUnderlying(underlying Type) {
+func (t *Named) SetUnderlying(u Type) {
 	assert(t.inst == nil)
-	if underlying == nil {
+	if u == nil {
 		panic("underlying type must not be nil")
 	}
-	if asNamed(underlying) != nil {
+	if asNamed(u) != nil {
 		panic("underlying type must not be *Named")
 	}
-	// Invariant: Presence of underlying type implies it was resolved.
-	t.fromRHS = underlying
+	// be careful to uphold the state invariants
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	t.fromRHS = u
 	t.allowNilRHS = false
-	t.resolve()
-	t.underlying = underlying
+	t.setState(resolved | complete) // TODO(markfreeman): Why complete?
+
+	t.underlying = u
 	t.allowNilUnderlying = false
+	t.setState(underlying)
 }
 
 // AddMethod adds method m unless it is already in the method list.
@@ -553,9 +585,10 @@ func (t *Named) String() string { return TypeString(t, nil) }
 // cycle is found, the result is Typ[Invalid]; if n.check != nil, the
 // cycle is also reported.
 func (n *Named) under() Type {
-	assert(n.state() >= resolved)
+	assert(n.stateHas(resolved))
 
-	if n.underlying != nil {
+	// optimization for likely case
+	if n.stateHas(underlying) {
 		return n.underlying
 	}
 
@@ -569,19 +602,34 @@ func (n *Named) under() Type {
 		switch t := rhs.(type) {
 		case nil:
 			u = Typ[Invalid]
+
 		case *Alias:
 			rhs = unalias(t)
+
 		case *Named:
 			if i, ok := seen[t]; ok {
 				n.check.cycleError(path[i:], firstInSrc(path[i:]))
 				u = Typ[Invalid]
 				break
 			}
+
+			// acquire the lock without checking; performance is probably fine
+			t.resolve()
+			t.mu.Lock()
+			defer t.mu.Unlock()
+
+			// t.underlying might have been set while we were locking
+			if t.stateHas(underlying) {
+				u = t.underlying
+				break
+			}
+
 			seen[t] = len(seen)
 			path = append(path, t.obj)
-			t.resolve()
+
 			assert(t.fromRHS != nil || t.allowNilRHS)
 			rhs = t.fromRHS
+
 		default:
 			u = rhs // any type literal works
 		}
@@ -590,6 +638,7 @@ func (n *Named) under() Type {
 	// go back up the chain
 	for t := range seen {
 		t.underlying = u
+		t.setState(underlying)
 	}
 
 	return u
@@ -659,7 +708,8 @@ func (n *Named) expandRHS() (rhs Type) {
 		}()
 	}
 
-	assert(n.state() == unresolved)
+	assert(!n.stateHas(resolved))
+	assert(n.inst.orig.stateHas(resolved | loaded))
 
 	if n.inst.ctxt == nil {
 		n.inst.ctxt = NewContext()
@@ -668,9 +718,6 @@ func (n *Named) expandRHS() (rhs Type) {
 	ctxt := n.inst.ctxt
 	orig := n.inst.orig
 
-	assert(orig.state() >= resolved)
-	assert(orig.fromRHS != nil)
-
 	targs := n.inst.targs
 	tpars := orig.tparams
 
diff --git a/src/go/types/named.go b/src/go/types/named.go
index faa7bc2a706a3c..35ca325db2554d 100644
--- a/src/go/types/named.go
+++ b/src/go/types/named.go
@@ -50,10 +50,8 @@ import (
 // soon.
 //
 // We achieve this by tracking state with an atomic state variable, and
-// guarding potentially concurrent calculations with a mutex. At any point in
-// time this state variable determines which data on N may be accessed. As
-// state monotonically progresses, any data available at state M may be
-// accessed without acquiring the mutex at state N, provided N >= M.
+// guarding potentially concurrent calculations with a mutex. See [stateMask]
+// for details.
 //
 // GLOSSARY: Here are a few terms used in this file to describe Named types:
 //  - We say that a Named type is "instantiated" if it has been constructed by
@@ -114,13 +112,13 @@ type Named struct {
 	allowNilRHS        bool // same as below, as well as briefly during checking of a type declaration
 	allowNilUnderlying bool // may be true from creation via [NewNamed] until [Named.SetUnderlying]
 
-	underlying Type      // underlying type, or nil
-	inst       *instance // information for instantiated types; nil otherwise
+	inst *instance // information for instantiated types; nil otherwise
 
-	mu      sync.Mutex     // guards all fields below
-	state_  uint32         // the current state of this type; must only be accessed atomically
-	fromRHS Type           // the declaration RHS this type is derived from
-	tparams *TypeParamList // type parameters, or nil
+	mu         sync.Mutex     // guards all fields below
+	state_     uint32         // the current state of this type; must only be accessed atomically or when mu is held
+	fromRHS    Type           // the declaration RHS this type is derived from
+	tparams    *TypeParamList // type parameters, or nil
+	underlying Type           // underlying type, or nil
 
 	// methods declared for this type (not the method set of this type)
 	// Signatures are type-checked lazily.
@@ -142,15 +140,43 @@ type instance struct {
 	ctxt            *Context  // local Context; set to nil after full expansion
 }
 
-// namedState represents the possible states that a named type may assume.
-type namedState uint32
+// stateMask represents each state in the lifecycle of a named type.
+//
+// Each named type begins in the unresolved state. A named type may transition to a new state
+// according to the below diagram:
+//
+//	unresolved
+//	loaded
+//	resolved
+//	└── complete
+//	└── underlying
+//
+// That is, descent down the tree is mostly linear (unresolved through resolved), except upon
+// reaching the leaves (complete and underlying). A type may occupy any combination of the
+// leaf states at once (they are independent states).
+//
+// To represent this independence, the set of active states is represented with a bit set. State
+// transitions are monotonic. Once a state bit is set, it remains set.
+//
+// The above constraints significantly narrow the possible bit sets for a named type. With bits
+// set left-to-right, they are:
+//
+//	0000 | unresolved
+//	1000 | loaded
+//	1100 | resolved, which implies loaded
+//	1110 | completed, which implies resolved (which in turn implies loaded)
+//	1101 | underlying, which implies resolved ...
+//	1111 | both completed and underlying which implies resolved ...
+//
+// To read the state of a named type, use [Named.stateHas]; to write, use [Named.setState].
+type stateMask uint32
 
-// Note: the order of states is relevant
 const (
-	unresolved namedState = iota // type parameters, RHS, underlying, and methods might be unavailable
-	resolved                     // resolve has run; methods might be unexpanded (for instances)
-	loaded                       // loader has run; constraints might be unexpanded (for generic types)
-	complete                     // all data is known
+	// before resolved, type parameters, RHS, underlying, and methods might be unavailable
+	resolved   stateMask = 1 << iota // methods might be unexpanded (for instances)
+	complete                         // methods are all expanded (for instances)
+	loaded                           // methods are available, but constraints might be unexpanded (for generic types)
+	underlying                       // underlying type is available
 )
 
 // NewNamed returns a new named type for the given type name, underlying type, and associated methods.
@@ -191,7 +217,7 @@ func NewNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
 // All others:
 // Effectively, nothing happens.
 func (n *Named) resolve() *Named {
-	if n.state() >= resolved { // avoid locking below
+	if n.stateHas(resolved | loaded) { // avoid locking below
 		return n
 	}
 
@@ -200,10 +226,14 @@ func (n *Named) resolve() *Named {
 	n.mu.Lock()
 	defer n.mu.Unlock()
 
-	if n.state() >= resolved {
+	// only atomic for consistency; we are holding the mutex
+	if n.stateHas(resolved | loaded) {
 		return n
 	}
 
+	// underlying comes after resolving, do not set it
+	defer (func() { assert(!n.stateHas(underlying)) })()
+
 	if n.inst != nil {
 		assert(n.fromRHS == nil) // instantiated types are not declared types
 		assert(n.loader == nil)  // cannot import an instantiation
@@ -215,7 +245,7 @@ func (n *Named) resolve() *Named {
 		n.tparams = orig.tparams
 
 		if len(orig.methods) == 0 {
-			n.setState(complete) // nothing further to do
+			n.setState(resolved | complete) // nothing further to do
 			n.inst.ctxt = nil
 		} else {
 			n.setState(resolved)
@@ -242,27 +272,24 @@ func (n *Named) resolve() *Named {
 		n.methods = methods
 
 		n.setState(loaded) // avoid deadlock calling delayed functions
-
 		for _, f := range delayed {
 			f()
 		}
 	}
 
-	assert(n.fromRHS != nil || n.allowNilRHS)
-	assert(n.underlying == nil) // underlying comes after resolving
-	n.setState(complete)
+	n.setState(resolved | complete)
 	return n
 }
 
-// state atomically accesses the current state of the receiver.
-func (n *Named) state() namedState {
-	return namedState(atomic.LoadUint32(&n.state_))
+// stateHas atomically determines whether the current state includes any active bit in sm.
+func (n *Named) stateHas(sm stateMask) bool {
+	return atomic.LoadUint32(&n.state_)&uint32(sm) != 0
 }
 
-// setState atomically stores the given state for n.
+// setState atomically sets the current state to include each active bit in sm.
 // Must only be called while holding n.mu.
-func (n *Named) setState(state namedState) {
-	atomic.StoreUint32(&n.state_, uint32(state))
+func (n *Named) setState(sm stateMask) {
+	atomic.OrUint32(&n.state_, uint32(sm))
 }
 
 // newNamed is like NewNamed but with a *Checker receiver.
@@ -372,7 +399,7 @@ func (t *Named) NumMethods() int {
 func (t *Named) Method(i int) *Func {
 	t.resolve()
 
-	if t.state() >= complete {
+	if t.stateHas(complete) {
 		return t.methods[i]
 	}
 
@@ -464,20 +491,25 @@ func (t *Named) expandMethod(i int) *Func {
 
 // SetUnderlying sets the underlying type and marks t as complete.
 // t must not have type arguments.
-func (t *Named) SetUnderlying(underlying Type) {
+func (t *Named) SetUnderlying(u Type) {
 	assert(t.inst == nil)
-	if underlying == nil {
+	if u == nil {
 		panic("underlying type must not be nil")
 	}
-	if asNamed(underlying) != nil {
+	if asNamed(u) != nil {
 		panic("underlying type must not be *Named")
 	}
-	// Invariant: Presence of underlying type implies it was resolved.
-	t.fromRHS = underlying
+	// be careful to uphold the state invariants
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	t.fromRHS = u
 	t.allowNilRHS = false
-	t.resolve()
-	t.underlying = underlying
+	t.setState(resolved | complete) // TODO(markfreeman): Why complete?
+
+	t.underlying = u
 	t.allowNilUnderlying = false
+	t.setState(underlying)
 }
 
 // AddMethod adds method m unless it is already in the method list.
@@ -556,9 +588,10 @@ func (t *Named) String() string { return TypeString(t, nil) }
 // cycle is found, the result is Typ[Invalid]; if n.check != nil, the
 // cycle is also reported.
 func (n *Named) under() Type {
-	assert(n.state() >= resolved)
+	assert(n.stateHas(resolved))
 
-	if n.underlying != nil {
+	// optimization for likely case
+	if n.stateHas(underlying) {
 		return n.underlying
 	}
 
@@ -572,19 +605,34 @@ func (n *Named) under() Type {
 		switch t := rhs.(type) {
 		case nil:
 			u = Typ[Invalid]
+
 		case *Alias:
 			rhs = unalias(t)
+
 		case *Named:
 			if i, ok := seen[t]; ok {
 				n.check.cycleError(path[i:], firstInSrc(path[i:]))
 				u = Typ[Invalid]
 				break
 			}
+
+			// acquire the lock without checking; performance is probably fine
+			t.resolve()
+			t.mu.Lock()
+			defer t.mu.Unlock()
+
+			// t.underlying might have been set while we were locking
+			if t.stateHas(underlying) {
+				u = t.underlying
+				break
+			}
+
 			seen[t] = len(seen)
 			path = append(path, t.obj)
-			t.resolve()
+
 			assert(t.fromRHS != nil || t.allowNilRHS)
 			rhs = t.fromRHS
+
 		default:
 			u = rhs // any type literal works
 		}
@@ -593,6 +641,7 @@ func (n *Named) under() Type {
 	// go back up the chain
 	for t := range seen {
 		t.underlying = u
+		t.setState(underlying)
 	}
 
 	return u
@@ -662,7 +711,8 @@ func (n *Named) expandRHS() (rhs Type) {
 		}()
 	}
 
-	assert(n.state() == unresolved)
+	assert(!n.stateHas(resolved))
+	assert(n.inst.orig.stateHas(resolved | loaded))
 
 	if n.inst.ctxt == nil {
 		n.inst.ctxt = NewContext()
@@ -671,9 +721,6 @@ func (n *Named) expandRHS() (rhs Type) {
 	ctxt := n.inst.ctxt
 	orig := n.inst.orig
 
-	assert(orig.state() >= resolved)
-	assert(orig.fromRHS != nil)
-
 	targs := n.inst.targs
 	tpars := orig.tparams
 

From 6c3d0d259f2d83a338a3a7da268e2dd5834aa35f Mon Sep 17 00:00:00 2001
From: "Matt T. Proud" 
Date: Thu, 16 Oct 2025 19:14:45 +0200
Subject: [PATCH 221/229] path/filepath: reword documentation for Rel

The existing func Rel's API documentation was presented in a rather
dense way without a lot of organization that oriented around topical
flow, so the documentation has been cleaned up to present the
function's behavior more clearly and concisely.

Fixes #75893

Change-Id: I6c8f6ef508250397be9d0127a15508e7335f18c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/712440
Reviewed-by: David Chase 
Auto-Submit: Dmitri Shuralyov 
Reviewed-by: Dmitri Shuralyov 
TryBot-Bypass: Dmitri Shuralyov 
Reviewed-by: Dmitri Shuralyov 
---
 src/path/filepath/path.go | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/src/path/filepath/path.go b/src/path/filepath/path.go
index dc6975242a928c..ecf201ac000bde 100644
--- a/src/path/filepath/path.go
+++ b/src/path/filepath/path.go
@@ -173,19 +173,20 @@ func unixAbs(path string) (string, error) {
 	return Join(wd, path), nil
 }
 
-// Rel returns a relative path that is lexically equivalent to targpath when
-// joined to basepath with an intervening separator. That is,
-// [Join](basepath, Rel(basepath, targpath)) is equivalent to targpath itself.
-// On success, the returned path will always be relative to basepath,
-// even if basepath and targpath share no elements.
-// An error is returned if targpath can't be made relative to basepath or if
-// knowing the current working directory would be necessary to compute it.
-// Rel calls [Clean] on the result.
-func Rel(basepath, targpath string) (string, error) {
-	baseVol := VolumeName(basepath)
-	targVol := VolumeName(targpath)
-	base := Clean(basepath)
-	targ := Clean(targpath)
+// Rel returns a relative path that is lexically equivalent to targPath when
+// joined to basePath with an intervening separator. That is,
+// [Join](basePath, Rel(basePath, targPath)) is equivalent to targPath itself.
+//
+// The returned path will always be relative to basePath, even if basePath and
+// targPath share no elements. Rel calls [Clean] on the result.
+//
+// An error is returned if targPath can't be made relative to basePath
+// or if knowing the current working directory would be necessary to compute it.
+func Rel(basePath, targPath string) (string, error) {
+	baseVol := VolumeName(basePath)
+	targVol := VolumeName(targPath)
+	base := Clean(basePath)
+	targ := Clean(targPath)
 	if sameWord(targ, base) {
 		return ".", nil
 	}
@@ -194,7 +195,7 @@ func Rel(basepath, targpath string) (string, error) {
 	if base == "." {
 		base = ""
 	} else if base == "" && filepathlite.VolumeNameLen(baseVol) > 2 /* isUNC */ {
-		// Treat any targetpath matching `\\host\share` basepath as absolute path.
+		// Treat any targetpath matching `\\host\share` basePath as absolute path.
 		base = string(Separator)
 	}
 
@@ -202,7 +203,7 @@ func Rel(basepath, targpath string) (string, error) {
 	baseSlashed := len(base) > 0 && base[0] == Separator
 	targSlashed := len(targ) > 0 && targ[0] == Separator
 	if baseSlashed != targSlashed || !sameWord(baseVol, targVol) {
-		return "", errors.New("Rel: can't make " + targpath + " relative to " + basepath)
+		return "", errors.New("Rel: can't make " + targPath + " relative to " + basePath)
 	}
 	// Position base[b0:bi] and targ[t0:ti] at the first differing elements.
 	bl := len(base)
@@ -228,7 +229,7 @@ func Rel(basepath, targpath string) (string, error) {
 		t0 = ti
 	}
 	if base[b0:bi] == ".." {
-		return "", errors.New("Rel: can't make " + targpath + " relative to " + basepath)
+		return "", errors.New("Rel: can't make " + targPath + " relative to " + basePath)
 	}
 	if b0 != bl {
 		// Base elements left. Must go up before going down.

From 06e57e60a7ff6cbc9c608278cbac4db514c7161a Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Mon, 20 Oct 2025 15:02:23 -0700
Subject: [PATCH 222/229] go/types, types2: only report version errors if
 new(expr) is ok otherwise

If new(expr) is used before Go 1.26, don't report version errors if there
are other problems with the expression.

While at it, implement multiple missing type checks for new(expr) and
add corresponding test cases that were missed in CL 704935 (tests for
no value expressions, generic types, untyped nil).

Reorganize/rename builtins0.go tests for new to match existing test case
patterns again.

Fixes #75986.
For #45624.

Change-Id: I39e5516d3f8d191cc390a4d8b9911c312bbb177c
Reviewed-on: https://go-review.googlesource.com/c/go/+/713241
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Mark Freeman 
Reviewed-by: Robert Griesemer 
Auto-Submit: Robert Griesemer 
---
 src/cmd/compile/internal/types2/builtins.go   | 32 +++++++--------
 src/go/types/builtins.go                      | 32 +++++++--------
 .../types/testdata/check/builtins0.go         | 40 ++++++++++++-------
 src/internal/types/testdata/check/go1_25.go   |  7 +++-
 .../types/testdata/fixedbugs/issue75986.go    | 28 +++++++++++++
 5 files changed, 91 insertions(+), 48 deletions(-)
 create mode 100644 src/internal/types/testdata/fixedbugs/issue75986.go

diff --git a/src/cmd/compile/internal/types2/builtins.go b/src/cmd/compile/internal/types2/builtins.go
index 84acb4ca484164..d4463bc4b09a5f 100644
--- a/src/cmd/compile/internal/types2/builtins.go
+++ b/src/cmd/compile/internal/types2/builtins.go
@@ -639,31 +639,31 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 		// new(T) or new(expr)
 		// (no argument evaluated yet)
 		arg := argList[0]
-		check.exprOrType(x, arg, true)
-		var T Type
+		check.exprOrType(x, arg, false)
+		check.exclude(x, 1<
Date: Thu, 28 Aug 2025 21:40:57 -0400
Subject: [PATCH 223/229] go/ast: add ParseDirective for parsing directive
 comments

This adds an ast.Directive API for parsing directive comments such as
"//go:build" and "//go:embed".

This will help tools standardize the syntax of these directive
comments. Even within the standard Go tools there's little agreement
on the finer details of the syntax of directives today.

Fixes #68021.

Change-Id: I84a988a667682c9ac70632df6e925461ac95e381
Reviewed-on: https://go-review.googlesource.com/c/go/+/704835
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Austin Clements 
Reviewed-by: Mateusz Poliwczak 
Reviewed-by: Alan Donovan 
---
 api/next/68021.txt                         |  13 ++
 doc/next/6-stdlib/99-minor/go/ast/68021.md |   4 +
 src/go/ast/directive.go                    | 179 +++++++++++++++
 src/go/ast/directive_test.go               | 251 +++++++++++++++++++++
 4 files changed, 447 insertions(+)
 create mode 100644 api/next/68021.txt
 create mode 100644 doc/next/6-stdlib/99-minor/go/ast/68021.md
 create mode 100644 src/go/ast/directive.go
 create mode 100644 src/go/ast/directive_test.go

diff --git a/api/next/68021.txt b/api/next/68021.txt
new file mode 100644
index 00000000000000..46156e06654878
--- /dev/null
+++ b/api/next/68021.txt
@@ -0,0 +1,13 @@
+pkg go/ast, func ParseDirective(token.Pos, string) (Directive, bool) #68021
+pkg go/ast, method (*Directive) End() token.Pos #68021
+pkg go/ast, method (*Directive) ParseArgs() ([]DirectiveArg, error) #68021
+pkg go/ast, method (*Directive) Pos() token.Pos #68021
+pkg go/ast, type Directive struct #68021
+pkg go/ast, type Directive struct, Args string #68021
+pkg go/ast, type Directive struct, ArgsPos token.Pos #68021
+pkg go/ast, type Directive struct, Name string #68021
+pkg go/ast, type Directive struct, Slash token.Pos #68021
+pkg go/ast, type Directive struct, Tool string #68021
+pkg go/ast, type DirectiveArg struct #68021
+pkg go/ast, type DirectiveArg struct, Arg string #68021
+pkg go/ast, type DirectiveArg struct, Pos token.Pos #68021
diff --git a/doc/next/6-stdlib/99-minor/go/ast/68021.md b/doc/next/6-stdlib/99-minor/go/ast/68021.md
new file mode 100644
index 00000000000000..0ff1a0b11e8e0c
--- /dev/null
+++ b/doc/next/6-stdlib/99-minor/go/ast/68021.md
@@ -0,0 +1,4 @@
+The new [ParseDirective] function parses [directive
+comments](/doc/comment#Syntax), which are comments such as `//go:generate`.
+Source code tools can support their own directive comments and this new API
+should help them implement the conventional syntax.
diff --git a/src/go/ast/directive.go b/src/go/ast/directive.go
new file mode 100644
index 00000000000000..901ed0ba0e0eb1
--- /dev/null
+++ b/src/go/ast/directive.go
@@ -0,0 +1,179 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ast
+
+import (
+	"fmt"
+	"go/token"
+	"strconv"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+// A Directive is a comment of this form:
+//
+//	//tool:name args
+//
+// For example, this directive:
+//
+//	//go:generate stringer -type Op -trimprefix Op
+//
+// would have Tool "go", Name "generate", and Args "stringer -type Op
+// -trimprefix Op".
+//
+// While Args does not have a strict syntax, by convention it is a
+// space-separated sequence of unquoted words, '"'-quoted Go strings, or
+// '`'-quoted raw strings.
+//
+// See https://go.dev/doc/comment#directives for specification.
+type Directive struct {
+	Tool string
+	Name string
+	Args string // no leading or trailing whitespace
+
+	// Slash is the position of the "//" at the beginning of the directive.
+	Slash token.Pos
+
+	// ArgsPos is the position where Args begins, based on the position passed
+	// to ParseDirective.
+	ArgsPos token.Pos
+}
+
+// ParseDirective parses a single comment line for a directive comment.
+//
+// If the line is not a directive comment, it returns false.
+//
+// The provided text must be a single line and should include the leading "//".
+// If the text does not start with "//", it returns false.
+//
+// The caller may provide a file position of the start of c. This will be used
+// to track the position of the arguments. This may be [Comment.Slash],
+// synthesized by the caller, or simply 0. If the caller passes 0, then the
+// positions are effectively byte offsets into the string c.
+func ParseDirective(pos token.Pos, c string) (Directive, bool) {
+	// Fast path to eliminate most non-directive comments. Must be a line
+	// comment starting with [a-z0-9]
+	if !(len(c) >= 3 && c[0] == '/' && c[1] == '/' && isalnum(c[2])) {
+		return Directive{}, false
+	}
+
+	buf := directiveScanner{c, pos}
+	buf.skip(len("//"))
+
+	// Check for a valid directive and parse tool part.
+	//
+	// This logic matches isDirective. (We could combine them, but isDirective
+	// itself is duplicated in several places.)
+	colon := strings.Index(buf.str, ":")
+	if colon <= 0 || colon+1 >= len(buf.str) {
+		return Directive{}, false
+	}
+	for i := 0; i <= colon+1; i++ {
+		if i == colon {
+			continue
+		}
+		if !isalnum(buf.str[i]) {
+			return Directive{}, false
+		}
+	}
+	tool := buf.take(colon)
+	buf.skip(len(":"))
+
+	// Parse name and args.
+	name := buf.takeNonSpace()
+	buf.skipSpace()
+	argsPos := buf.pos
+	args := strings.TrimRightFunc(buf.str, unicode.IsSpace)
+
+	return Directive{tool, name, args, pos, argsPos}, true
+}
+
+func isalnum(b byte) bool {
+	return 'a' <= b && b <= 'z' || '0' <= b && b <= '9'
+}
+
+func (d *Directive) Pos() token.Pos { return d.Slash }
+func (d *Directive) End() token.Pos { return token.Pos(int(d.ArgsPos) + len(d.Args)) }
+
+// A DirectiveArg is an argument to a directive comment.
+type DirectiveArg struct {
+	// Arg is the parsed argument string. If the argument was a quoted string,
+	// this is its unquoted form.
+	Arg string
+	// Pos is the position of the first character in this argument.
+	Pos token.Pos
+}
+
+// ParseArgs parses a [Directive]'s arguments using the standard convention,
+// which is a sequence of tokens, where each token may be a bare word, or a
+// double quoted Go string, or a back quoted raw Go string. Each token must be
+// separated by one or more Unicode spaces.
+//
+// If the arguments do not conform to this syntax, it returns an error.
+func (d *Directive) ParseArgs() ([]DirectiveArg, error) {
+	args := directiveScanner{d.Args, d.ArgsPos}
+
+	list := []DirectiveArg{}
+	for args.skipSpace(); args.str != ""; args.skipSpace() {
+		var arg string
+		argPos := args.pos
+
+		switch args.str[0] {
+		default:
+			arg = args.takeNonSpace()
+
+		case '`', '"':
+			q, err := strconv.QuotedPrefix(args.str)
+			if err != nil { // Always strconv.ErrSyntax
+				return nil, fmt.Errorf("invalid quoted string in //%s:%s: %s", d.Tool, d.Name, args.str)
+			}
+			// Any errors will have been returned by QuotedPrefix
+			arg, _ = strconv.Unquote(args.take(len(q)))
+
+			// Check that the quoted string is followed by a space (or nothing)
+			if args.str != "" {
+				r, _ := utf8.DecodeRuneInString(args.str)
+				if !unicode.IsSpace(r) {
+					return nil, fmt.Errorf("invalid quoted string in //%s:%s: %s", d.Tool, d.Name, args.str)
+				}
+			}
+		}
+
+		list = append(list, DirectiveArg{arg, argPos})
+	}
+	return list, nil
+}
+
+// directiveScanner is a helper for parsing directive comments while maintaining
+// position information.
+type directiveScanner struct {
+	str string
+	pos token.Pos
+}
+
+func (s *directiveScanner) skip(n int) {
+	s.pos += token.Pos(n)
+	s.str = s.str[n:]
+}
+
+func (s *directiveScanner) take(n int) string {
+	res := s.str[:n]
+	s.skip(n)
+	return res
+}
+
+func (s *directiveScanner) takeNonSpace() string {
+	i := strings.IndexFunc(s.str, unicode.IsSpace)
+	if i == -1 {
+		i = len(s.str)
+	}
+	return s.take(i)
+}
+
+func (s *directiveScanner) skipSpace() {
+	trim := strings.TrimLeftFunc(s.str, unicode.IsSpace)
+	s.skip(len(s.str) - len(trim))
+}
diff --git a/src/go/ast/directive_test.go b/src/go/ast/directive_test.go
new file mode 100644
index 00000000000000..ffabe584cb820b
--- /dev/null
+++ b/src/go/ast/directive_test.go
@@ -0,0 +1,251 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ast
+
+import (
+	"go/token"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestParseDirectiveMatchesIsDirective(t *testing.T) {
+	for _, tt := range isDirectiveTests {
+		want := tt.ok
+		if strings.HasPrefix(tt.in, "extern ") || strings.HasPrefix(tt.in, "export ") {
+			// ParseDirective does NOT support extern or export, unlike
+			// isDirective.
+			want = false
+		}
+
+		if _, ok := ParseDirective(0, "//"+tt.in); ok != want {
+			t.Errorf("ParseDirective(0, %q) = %v, want %v", "// "+tt.in, ok, want)
+		}
+	}
+}
+
+func TestParseDirective(t *testing.T) {
+	for _, test := range []struct {
+		name   string
+		in     string
+		pos    token.Pos
+		want   Directive
+		wantOK bool
+	}{
+		{
+			name: "valid",
+			in:   "//go:generate stringer -type Op -trimprefix Op",
+			pos:  10,
+			want: Directive{
+				Tool:    "go",
+				Name:    "generate",
+				Args:    "stringer -type Op -trimprefix Op",
+				Slash:   10,
+				ArgsPos: token.Pos(10 + len("//go:generate ")),
+			},
+			wantOK: true,
+		},
+		{
+			name: "no args",
+			in:   "//go:build ignore",
+			pos:  20,
+			want: Directive{
+				Tool:    "go",
+				Name:    "build",
+				Args:    "ignore",
+				Slash:   20,
+				ArgsPos: token.Pos(20 + len("//go:build ")),
+			},
+			wantOK: true,
+		},
+		{
+			name:   "not a directive",
+			in:     "// not a directive",
+			pos:    30,
+			wantOK: false,
+		},
+		{
+			name:   "not a comment",
+			in:     "go:generate",
+			pos:    40,
+			wantOK: false,
+		},
+		{
+			name:   "empty",
+			in:     "",
+			pos:    50,
+			wantOK: false,
+		},
+		{
+			name:   "just slashes",
+			in:     "//",
+			pos:    60,
+			wantOK: false,
+		},
+		{
+			name:   "no name",
+			in:     "//go:",
+			pos:    70,
+			wantOK: false,
+		},
+		{
+			name:   "no tool",
+			in:     "//:generate",
+			pos:    80,
+			wantOK: false,
+		},
+		{
+			name: "multiple spaces",
+			in:   "//go:build  foo bar",
+			pos:  90,
+			want: Directive{
+				Tool:    "go",
+				Name:    "build",
+				Args:    "foo bar",
+				Slash:   90,
+				ArgsPos: token.Pos(90 + len("//go:build  ")),
+			},
+			wantOK: true,
+		},
+		{
+			name: "trailing space",
+			in:   "//go:build foo ",
+			pos:  100,
+			want: Directive{
+				Tool:    "go",
+				Name:    "build",
+				Args:    "foo",
+				Slash:   100,
+				ArgsPos: token.Pos(100 + len("//go:build ")),
+			},
+			wantOK: true,
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			got, gotOK := ParseDirective(test.pos, test.in)
+			if gotOK != test.wantOK {
+				t.Fatalf("ParseDirective(%q) ok = %v, want %v", test.in, gotOK, test.wantOK)
+			}
+			if !reflect.DeepEqual(got, test.want) {
+				t.Errorf("ParseDirective(%q) = %+v, want %+v", test.in, got, test.want)
+			}
+		})
+	}
+}
+
+func TestParseArgs(t *testing.T) {
+	for _, test := range []struct {
+		name    string
+		in      Directive
+		want    []DirectiveArg
+		wantErr bool
+	}{
+		{
+			name: "simple",
+			in: Directive{
+				Tool:    "go",
+				Name:    "generate",
+				Args:    "stringer -type Op",
+				ArgsPos: 10,
+			},
+			want: []DirectiveArg{
+				{"stringer", 10},
+				{"-type", token.Pos(10 + len("stringer "))},
+				{"Op", token.Pos(10 + len("stringer -type "))},
+			},
+		},
+		{
+			name: "quoted",
+			in: Directive{
+				Tool:    "go",
+				Name:    "generate",
+				Args:    "\"foo bar\" baz",
+				ArgsPos: 10,
+			},
+			want: []DirectiveArg{
+				{"foo bar", 10},
+				{"baz", token.Pos(10 + len("\"foo bar\" "))},
+			},
+		},
+		{
+			name: "raw quoted",
+			in: Directive{
+				Tool:    "go",
+				Name:    "generate",
+				Args:    "`foo bar` baz",
+				ArgsPos: 10,
+			},
+			want: []DirectiveArg{
+				{"foo bar", 10},
+				{"baz", token.Pos(10 + len("`foo bar` "))},
+			},
+		},
+		{
+			name: "escapes",
+			in: Directive{
+				Tool:    "go",
+				Name:    "generate",
+				Args:    "\"foo\\U0001F60Abar\" `a\\tb`",
+				ArgsPos: 10,
+			},
+			want: []DirectiveArg{
+				{"foo😊bar", 10},
+				{"a\\tb", token.Pos(10 + len("\"foo\\U0001F60Abar\" "))},
+			},
+		},
+		{
+			name: "empty args",
+			in: Directive{
+				Tool:    "go",
+				Name:    "build",
+				Args:    "",
+				ArgsPos: 10,
+			},
+			want: []DirectiveArg{},
+		},
+		{
+			name: "spaces",
+			in: Directive{
+				Tool:    "go",
+				Name:    "build",
+				Args:    "  foo   bar  ",
+				ArgsPos: 10,
+			},
+			want: []DirectiveArg{
+				{"foo", token.Pos(10 + len("  "))},
+				{"bar", token.Pos(10 + len("  foo   "))},
+			},
+		},
+		{
+			name: "unterminated quote",
+			in: Directive{
+				Tool: "go",
+				Name: "generate",
+				Args: "`foo",
+			},
+			wantErr: true,
+		},
+		{
+			name: "no space after quote",
+			in: Directive{
+				Tool: "go",
+				Name: "generate",
+				Args: `"foo"bar`,
+			},
+			wantErr: true,
+		},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			got, err := test.in.ParseArgs()
+			if err != nil && !test.wantErr {
+				t.Errorf("got ParseArgs(%+v) = error %s; want %+v", test.in, err, test.want)
+			} else if err == nil && test.wantErr {
+				t.Errorf("got ParseArgs(%+v) = %+v; want error", test.in, got)
+			} else if err == nil && !reflect.DeepEqual(got, test.want) {
+				t.Errorf("got ParseArgs(%+v) = %+v; want %+v", test.in, got, test.want)
+			}
+		})
+	}
+}

From 29d43df8ab212910487345c354491b67780798cf Mon Sep 17 00:00:00 2001
From: Austin Clements 
Date: Thu, 11 Sep 2025 16:17:45 -0400
Subject: [PATCH 224/229] go/build, cmd/go: use ast.ParseDirective for go:embed

Currently, "//go:embed" directives are read by bespoke parsers in
go/build and cmd/go/internal/modindex. Replace these bespoke parsers
with scanner.Scanner for finding these directives and
ast.ParseDirective for parsing them.

It's not clear why we had a bespoke parser just for finding
"//go:embed" directives in the first place. We have a bespoke parser
for reading imports in order to avoid having to read the entire source
file into memory, but if we're parsing embeds, we wind up reading the
entire source file into memory anyway. Using scanner.Scanner instead
eliminates some truly confusing code.

This also demonstrates that ast.ParseDirective as proposed in #68021
achieves useful API coverage.

Updates #68021.

Change-Id: Ieb68738121dcff605a6a704a8045ddd2ff35df35
Reviewed-on: https://go-review.googlesource.com/c/go/+/704836
LUCI-TryBot-Result: Go LUCI 
Auto-Submit: Austin Clements 
Reviewed-by: Alan Donovan 
---
 src/cmd/go/internal/modindex/build_read.go | 279 ++++-----------------
 src/go/build/read.go                       | 279 ++++-----------------
 2 files changed, 86 insertions(+), 472 deletions(-)

diff --git a/src/cmd/go/internal/modindex/build_read.go b/src/cmd/go/internal/modindex/build_read.go
index f05b215c19e9ad..f2e48f36cdff54 100644
--- a/src/cmd/go/internal/modindex/build_read.go
+++ b/src/cmd/go/internal/modindex/build_read.go
@@ -92,37 +92,24 @@ func (r *importReader) readByte() byte {
 	return c
 }
 
-// readByteNoBuf is like readByte but doesn't buffer the byte.
-// It exhausts r.buf before reading from r.b.
-func (r *importReader) readByteNoBuf() byte {
-	var c byte
-	var err error
-	if len(r.buf) > 0 {
-		c = r.buf[0]
-		r.buf = r.buf[1:]
-	} else {
-		c, err = r.b.ReadByte()
-		if err == nil && c == 0 {
-			err = errNUL
+// readRest reads the entire rest of the file into r.buf.
+func (r *importReader) readRest() {
+	for {
+		if len(r.buf) == cap(r.buf) {
+			// Grow the buffer
+			r.buf = append(r.buf, 0)[:len(r.buf)]
 		}
-	}
-
-	if err != nil {
-		if err == io.EOF {
-			r.eof = true
-		} else if r.err == nil {
-			r.err = err
+		n, err := r.b.Read(r.buf[len(r.buf):cap(r.buf)])
+		r.buf = r.buf[:len(r.buf)+n]
+		if err != nil {
+			if err == io.EOF {
+				r.eof = true
+			} else if r.err == nil {
+				r.err = err
+			}
+			break
 		}
-		return 0
 	}
-	r.pos.Offset++
-	if c == '\n' {
-		r.pos.Line++
-		r.pos.Column = 1
-	} else {
-		r.pos.Column++
-	}
-	return c
 }
 
 // peekByte returns the next byte from the input reader but does not advance beyond it.
@@ -185,130 +172,6 @@ func (r *importReader) nextByte(skipSpace bool) byte {
 	return c
 }
 
-var goEmbed = []byte("go:embed")
-
-// findEmbed advances the input reader to the next //go:embed comment.
-// It reports whether it found a comment.
-// (Otherwise it found an error or EOF.)
-func (r *importReader) findEmbed(first bool) bool {
-	// The import block scan stopped after a non-space character,
-	// so the reader is not at the start of a line on the first call.
-	// After that, each //go:embed extraction leaves the reader
-	// at the end of a line.
-	startLine := !first
-	var c byte
-	for r.err == nil && !r.eof {
-		c = r.readByteNoBuf()
-	Reswitch:
-		switch c {
-		default:
-			startLine = false
-
-		case '\n':
-			startLine = true
-
-		case ' ', '\t':
-			// leave startLine alone
-
-		case '"':
-			startLine = false
-			for r.err == nil {
-				if r.eof {
-					r.syntaxError()
-				}
-				c = r.readByteNoBuf()
-				if c == '\\' {
-					r.readByteNoBuf()
-					if r.err != nil {
-						r.syntaxError()
-						return false
-					}
-					continue
-				}
-				if c == '"' {
-					c = r.readByteNoBuf()
-					goto Reswitch
-				}
-			}
-			goto Reswitch
-
-		case '`':
-			startLine = false
-			for r.err == nil {
-				if r.eof {
-					r.syntaxError()
-				}
-				c = r.readByteNoBuf()
-				if c == '`' {
-					c = r.readByteNoBuf()
-					goto Reswitch
-				}
-			}
-
-		case '\'':
-			startLine = false
-			for r.err == nil {
-				if r.eof {
-					r.syntaxError()
-				}
-				c = r.readByteNoBuf()
-				if c == '\\' {
-					r.readByteNoBuf()
-					if r.err != nil {
-						r.syntaxError()
-						return false
-					}
-					continue
-				}
-				if c == '\'' {
-					c = r.readByteNoBuf()
-					goto Reswitch
-				}
-			}
-
-		case '/':
-			c = r.readByteNoBuf()
-			switch c {
-			default:
-				startLine = false
-				goto Reswitch
-
-			case '*':
-				var c1 byte
-				for (c != '*' || c1 != '/') && r.err == nil {
-					if r.eof {
-						r.syntaxError()
-					}
-					c, c1 = c1, r.readByteNoBuf()
-				}
-				startLine = false
-
-			case '/':
-				if startLine {
-					// Try to read this as a //go:embed comment.
-					for i := range goEmbed {
-						c = r.readByteNoBuf()
-						if c != goEmbed[i] {
-							goto SkipSlashSlash
-						}
-					}
-					c = r.readByteNoBuf()
-					if c == ' ' || c == '\t' {
-						// Found one!
-						return true
-					}
-				}
-			SkipSlashSlash:
-				for c != '\n' && r.err == nil && !r.eof {
-					c = r.readByteNoBuf()
-				}
-				startLine = true
-			}
-		}
-	}
-	return false
-}
-
 // readKeyword reads the given keyword from the input.
 // If the keyword is not present, readKeyword records a syntax error.
 func (r *importReader) readKeyword(kw string) {
@@ -429,9 +292,7 @@ func readGoInfo(f io.Reader, info *fileInfo) error {
 	// we are sure we don't change the errors that go/parser returns.
 	if r.err == errSyntax {
 		r.err = nil
-		for r.err == nil && !r.eof {
-			r.readByte()
-		}
+		r.readRest()
 		info.header = r.buf
 	}
 	if r.err != nil {
@@ -504,23 +365,23 @@ func readGoInfo(f io.Reader, info *fileInfo) error {
 	// (near the package statement or imports), the compiler
 	// will reject them. They can be (and have already been) ignored.
 	if hasEmbed {
-		var line []byte
-		for first := true; r.findEmbed(first); first = false {
-			line = line[:0]
-			pos := r.pos
-			for {
-				c := r.readByteNoBuf()
-				if c == '\n' || r.err != nil || r.eof {
-					break
-				}
-				line = append(line, c)
+		r.readRest()
+		fset := token.NewFileSet()
+		file := fset.AddFile(r.pos.Filename, -1, len(r.buf))
+		var sc scanner.Scanner
+		sc.Init(file, r.buf, nil, scanner.ScanComments)
+		for {
+			pos, tok, lit := sc.Scan()
+			if tok == token.EOF {
+				break
 			}
-			// Add args if line is well-formed.
-			// Ignore badly-formed lines - the compiler will report them when it finds them,
-			// and we can pretend they are not there to help go list succeed with what it knows.
-			embs, err := parseGoEmbed(string(line), pos)
-			if err == nil {
-				info.embeds = append(info.embeds, embs...)
+			if tok == token.COMMENT && strings.HasPrefix(lit, "//go:embed") {
+				// Ignore badly-formed lines - the compiler will report them when it finds them,
+				// and we can pretend they are not there to help go list succeed with what it knows.
+				embs, err := parseGoEmbed(fset, pos, lit)
+				if err == nil {
+					info.embeds = append(info.embeds, embs...)
+				}
 			}
 		}
 	}
@@ -542,75 +403,21 @@ func isValidImport(s string) bool {
 	return s != ""
 }
 
-// parseGoEmbed parses the text following "//go:embed" to extract the glob patterns.
+// parseGoEmbed parses a "//go:embed" to extract the glob patterns.
 // It accepts unquoted space-separated patterns as well as double-quoted and back-quoted Go strings.
-// This is based on a similar function in cmd/compile/internal/gc/noder.go;
-// this version calculates position information as well.
-func parseGoEmbed(args string, pos token.Position) ([]fileEmbed, error) {
-	trimBytes := func(n int) {
-		pos.Offset += n
-		pos.Column += utf8.RuneCountInString(args[:n])
-		args = args[n:]
+// This must match the behavior of cmd/compile/internal/noder.go.
+func parseGoEmbed(fset *token.FileSet, pos token.Pos, comment string) ([]fileEmbed, error) {
+	dir, ok := ast.ParseDirective(pos, comment)
+	if !ok || dir.Tool != "go" || dir.Name != "embed" {
+		return nil, nil
 	}
-	trimSpace := func() {
-		trim := strings.TrimLeftFunc(args, unicode.IsSpace)
-		trimBytes(len(args) - len(trim))
+	args, err := dir.ParseArgs()
+	if err != nil {
+		return nil, err
 	}
-
 	var list []fileEmbed
-	for trimSpace(); args != ""; trimSpace() {
-		var path string
-		pathPos := pos
-	Switch:
-		switch args[0] {
-		default:
-			i := len(args)
-			for j, c := range args {
-				if unicode.IsSpace(c) {
-					i = j
-					break
-				}
-			}
-			path = args[:i]
-			trimBytes(i)
-
-		case '`':
-			var ok bool
-			path, _, ok = strings.Cut(args[1:], "`")
-			if !ok {
-				return nil, fmt.Errorf("invalid quoted string in //go:embed: %s", args)
-			}
-			trimBytes(1 + len(path) + 1)
-
-		case '"':
-			i := 1
-			for ; i < len(args); i++ {
-				if args[i] == '\\' {
-					i++
-					continue
-				}
-				if args[i] == '"' {
-					q, err := strconv.Unquote(args[:i+1])
-					if err != nil {
-						return nil, fmt.Errorf("invalid quoted string in //go:embed: %s", args[:i+1])
-					}
-					path = q
-					trimBytes(i + 1)
-					break Switch
-				}
-			}
-			if i >= len(args) {
-				return nil, fmt.Errorf("invalid quoted string in //go:embed: %s", args)
-			}
-		}
-
-		if args != "" {
-			r, _ := utf8.DecodeRuneInString(args)
-			if !unicode.IsSpace(r) {
-				return nil, fmt.Errorf("invalid quoted string in //go:embed: %s", args)
-			}
-		}
-		list = append(list, fileEmbed{path, pathPos})
+	for _, arg := range args {
+		list = append(list, fileEmbed{arg.Arg, fset.Position(arg.Pos)})
 	}
 	return list, nil
 }
diff --git a/src/go/build/read.go b/src/go/build/read.go
index 1273066dbc77c9..3185cf09bec72e 100644
--- a/src/go/build/read.go
+++ b/src/go/build/read.go
@@ -89,37 +89,24 @@ func (r *importReader) readByte() byte {
 	return c
 }
 
-// readByteNoBuf is like readByte but doesn't buffer the byte.
-// It exhausts r.buf before reading from r.b.
-func (r *importReader) readByteNoBuf() byte {
-	var c byte
-	var err error
-	if len(r.buf) > 0 {
-		c = r.buf[0]
-		r.buf = r.buf[1:]
-	} else {
-		c, err = r.b.ReadByte()
-		if err == nil && c == 0 {
-			err = errNUL
+// readRest reads the entire rest of the file into r.buf.
+func (r *importReader) readRest() {
+	for {
+		if len(r.buf) == cap(r.buf) {
+			// Grow the buffer
+			r.buf = append(r.buf, 0)[:len(r.buf)]
 		}
-	}
-
-	if err != nil {
-		if err == io.EOF {
-			r.eof = true
-		} else if r.err == nil {
-			r.err = err
+		n, err := r.b.Read(r.buf[len(r.buf):cap(r.buf)])
+		r.buf = r.buf[:len(r.buf)+n]
+		if err != nil {
+			if err == io.EOF {
+				r.eof = true
+			} else if r.err == nil {
+				r.err = err
+			}
+			break
 		}
-		return 0
 	}
-	r.pos.Offset++
-	if c == '\n' {
-		r.pos.Line++
-		r.pos.Column = 1
-	} else {
-		r.pos.Column++
-	}
-	return c
 }
 
 // peekByte returns the next byte from the input reader but does not advance beyond it.
@@ -182,130 +169,6 @@ func (r *importReader) nextByte(skipSpace bool) byte {
 	return c
 }
 
-var goEmbed = []byte("go:embed")
-
-// findEmbed advances the input reader to the next //go:embed comment.
-// It reports whether it found a comment.
-// (Otherwise it found an error or EOF.)
-func (r *importReader) findEmbed(first bool) bool {
-	// The import block scan stopped after a non-space character,
-	// so the reader is not at the start of a line on the first call.
-	// After that, each //go:embed extraction leaves the reader
-	// at the end of a line.
-	startLine := !first
-	var c byte
-	for r.err == nil && !r.eof {
-		c = r.readByteNoBuf()
-	Reswitch:
-		switch c {
-		default:
-			startLine = false
-
-		case '\n':
-			startLine = true
-
-		case ' ', '\t':
-			// leave startLine alone
-
-		case '"':
-			startLine = false
-			for r.err == nil {
-				if r.eof {
-					r.syntaxError()
-				}
-				c = r.readByteNoBuf()
-				if c == '\\' {
-					r.readByteNoBuf()
-					if r.err != nil {
-						r.syntaxError()
-						return false
-					}
-					continue
-				}
-				if c == '"' {
-					c = r.readByteNoBuf()
-					goto Reswitch
-				}
-			}
-			goto Reswitch
-
-		case '`':
-			startLine = false
-			for r.err == nil {
-				if r.eof {
-					r.syntaxError()
-				}
-				c = r.readByteNoBuf()
-				if c == '`' {
-					c = r.readByteNoBuf()
-					goto Reswitch
-				}
-			}
-
-		case '\'':
-			startLine = false
-			for r.err == nil {
-				if r.eof {
-					r.syntaxError()
-				}
-				c = r.readByteNoBuf()
-				if c == '\\' {
-					r.readByteNoBuf()
-					if r.err != nil {
-						r.syntaxError()
-						return false
-					}
-					continue
-				}
-				if c == '\'' {
-					c = r.readByteNoBuf()
-					goto Reswitch
-				}
-			}
-
-		case '/':
-			c = r.readByteNoBuf()
-			switch c {
-			default:
-				startLine = false
-				goto Reswitch
-
-			case '*':
-				var c1 byte
-				for (c != '*' || c1 != '/') && r.err == nil {
-					if r.eof {
-						r.syntaxError()
-					}
-					c, c1 = c1, r.readByteNoBuf()
-				}
-				startLine = false
-
-			case '/':
-				if startLine {
-					// Try to read this as a //go:embed comment.
-					for i := range goEmbed {
-						c = r.readByteNoBuf()
-						if c != goEmbed[i] {
-							goto SkipSlashSlash
-						}
-					}
-					c = r.readByteNoBuf()
-					if c == ' ' || c == '\t' {
-						// Found one!
-						return true
-					}
-				}
-			SkipSlashSlash:
-				for c != '\n' && r.err == nil && !r.eof {
-					c = r.readByteNoBuf()
-				}
-				startLine = true
-			}
-		}
-	}
-	return false
-}
-
 // readKeyword reads the given keyword from the input.
 // If the keyword is not present, readKeyword records a syntax error.
 func (r *importReader) readKeyword(kw string) {
@@ -436,9 +299,7 @@ func readGoInfo(f io.Reader, info *fileInfo) error {
 	// we are sure we don't change the errors that go/parser returns.
 	if r.err == errSyntax {
 		r.err = nil
-		for r.err == nil && !r.eof {
-			r.readByte()
-		}
+		r.readRest()
 		info.header = r.buf
 	}
 	if r.err != nil {
@@ -511,23 +372,23 @@ func readGoInfo(f io.Reader, info *fileInfo) error {
 	// (near the package statement or imports), the compiler
 	// will reject them. They can be (and have already been) ignored.
 	if hasEmbed {
-		var line []byte
-		for first := true; r.findEmbed(first); first = false {
-			line = line[:0]
-			pos := r.pos
-			for {
-				c := r.readByteNoBuf()
-				if c == '\n' || r.err != nil || r.eof {
-					break
-				}
-				line = append(line, c)
+		r.readRest()
+		fset := token.NewFileSet()
+		file := fset.AddFile(r.pos.Filename, -1, len(r.buf))
+		var sc scanner.Scanner
+		sc.Init(file, r.buf, nil, scanner.ScanComments)
+		for {
+			pos, tok, lit := sc.Scan()
+			if tok == token.EOF {
+				break
 			}
-			// Add args if line is well-formed.
-			// Ignore badly-formed lines - the compiler will report them when it finds them,
-			// and we can pretend they are not there to help go list succeed with what it knows.
-			embs, err := parseGoEmbed(string(line), pos)
-			if err == nil {
-				info.embeds = append(info.embeds, embs...)
+			if tok == token.COMMENT && strings.HasPrefix(lit, "//go:embed") {
+				// Ignore badly-formed lines - the compiler will report them when it finds them,
+				// and we can pretend they are not there to help go list succeed with what it knows.
+				embs, err := parseGoEmbed(fset, pos, lit)
+				if err == nil {
+					info.embeds = append(info.embeds, embs...)
+				}
 			}
 		}
 	}
@@ -549,75 +410,21 @@ func isValidImport(s string) bool {
 	return s != ""
 }
 
-// parseGoEmbed parses the text following "//go:embed" to extract the glob patterns.
+// parseGoEmbed parses a "//go:embed" to extract the glob patterns.
 // It accepts unquoted space-separated patterns as well as double-quoted and back-quoted Go strings.
-// This is based on a similar function in cmd/compile/internal/gc/noder.go;
-// this version calculates position information as well.
-func parseGoEmbed(args string, pos token.Position) ([]fileEmbed, error) {
-	trimBytes := func(n int) {
-		pos.Offset += n
-		pos.Column += utf8.RuneCountInString(args[:n])
-		args = args[n:]
+// This must match the behavior of cmd/compile/internal/noder.go.
+func parseGoEmbed(fset *token.FileSet, pos token.Pos, comment string) ([]fileEmbed, error) {
+	dir, ok := ast.ParseDirective(pos, comment)
+	if !ok || dir.Tool != "go" || dir.Name != "embed" {
+		return nil, nil
 	}
-	trimSpace := func() {
-		trim := strings.TrimLeftFunc(args, unicode.IsSpace)
-		trimBytes(len(args) - len(trim))
+	args, err := dir.ParseArgs()
+	if err != nil {
+		return nil, err
 	}
-
 	var list []fileEmbed
-	for trimSpace(); args != ""; trimSpace() {
-		var path string
-		pathPos := pos
-	Switch:
-		switch args[0] {
-		default:
-			i := len(args)
-			for j, c := range args {
-				if unicode.IsSpace(c) {
-					i = j
-					break
-				}
-			}
-			path = args[:i]
-			trimBytes(i)
-
-		case '`':
-			var ok bool
-			path, _, ok = strings.Cut(args[1:], "`")
-			if !ok {
-				return nil, fmt.Errorf("invalid quoted string in //go:embed: %s", args)
-			}
-			trimBytes(1 + len(path) + 1)
-
-		case '"':
-			i := 1
-			for ; i < len(args); i++ {
-				if args[i] == '\\' {
-					i++
-					continue
-				}
-				if args[i] == '"' {
-					q, err := strconv.Unquote(args[:i+1])
-					if err != nil {
-						return nil, fmt.Errorf("invalid quoted string in //go:embed: %s", args[:i+1])
-					}
-					path = q
-					trimBytes(i + 1)
-					break Switch
-				}
-			}
-			if i >= len(args) {
-				return nil, fmt.Errorf("invalid quoted string in //go:embed: %s", args)
-			}
-		}
-
-		if args != "" {
-			r, _ := utf8.DecodeRuneInString(args)
-			if !unicode.IsSpace(r) {
-				return nil, fmt.Errorf("invalid quoted string in //go:embed: %s", args)
-			}
-		}
-		list = append(list, fileEmbed{path, pathPos})
+	for _, arg := range args {
+		list = append(list, fileEmbed{arg.Arg, fset.Position(arg.Pos)})
 	}
 	return list, nil
 }

From 4bdb55b5b86fc96addd43a845dabf6b76d100202 Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Thu, 16 Oct 2025 16:58:25 -0700
Subject: [PATCH 225/229] go/types, types2: rename Named.under to
 Named.resolveUnderlying

Named.resolveUnderlying is now just a helper function for Underlying
and only called from there. The name makes is clearer what this function
does; it also doesn't need to return a result anymore.

While at it, slightly simplify the function body.

Change-Id: I167c4be89b1bfcc69f6b528ddb6ed4c90481194a
Reviewed-on: https://go-review.googlesource.com/c/go/+/712521
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Mark Freeman 
Auto-Submit: Robert Griesemer 
Reviewed-by: Robert Griesemer 
---
 src/cmd/compile/internal/types2/named.go | 29 ++++++++++++------------
 src/go/types/named.go                    | 29 ++++++++++++------------
 2 files changed, 28 insertions(+), 30 deletions(-)

diff --git a/src/cmd/compile/internal/types2/named.go b/src/cmd/compile/internal/types2/named.go
index 8f3249e44ed99e..856f33028a41a1 100644
--- a/src/cmd/compile/internal/types2/named.go
+++ b/src/cmd/compile/internal/types2/named.go
@@ -335,7 +335,7 @@ func (n *Named) cleanup() {
 	// Instances can have a nil underlying at the end of type checking — they
 	// will lazily expand it as needed. All other types must have one.
 	if n.inst == nil {
-		n.resolve().under()
+		n.Underlying()
 	}
 	n.check = nil
 }
@@ -562,7 +562,8 @@ func (n *Named) Underlying() Type {
 		}
 	}
 
-	return n.under()
+	n.resolveUnderlying()
+	return n.underlying
 }
 
 func (t *Named) String() string { return TypeString(t, nil) }
@@ -573,7 +574,7 @@ func (t *Named) String() string { return TypeString(t, nil) }
 // TODO(rfindley): reorganize the loading and expansion methods under this
 // heading.
 
-// under returns the (possibly expanded) underlying type of n.
+// resolveUnderlying computes the underlying type of n.
 //
 // It does so by following RHS type chains. If a type literal is found, each
 // named type in the chain has its underlying set to that type. Aliases are
@@ -581,24 +582,22 @@ func (t *Named) String() string { return TypeString(t, nil) }
 //
 // This function also checks for instantiated layout cycles, which are
 // reachable only in the case where resolve() expanded an instantiated
-// type which became self-referencing without indirection. If such a
-// cycle is found, the result is Typ[Invalid]; if n.check != nil, the
-// cycle is also reported.
-func (n *Named) under() Type {
+// type which became self-referencing without indirection.
+// If such a cycle is found, the underlying type is set to Typ[Invalid]
+// and a cycle is reported.
+func (n *Named) resolveUnderlying() {
 	assert(n.stateHas(resolved))
 
 	// optimization for likely case
 	if n.stateHas(underlying) {
-		return n.underlying
+		return
 	}
 
-	var rhs Type = n
-	var u Type
-
 	seen := make(map[*Named]int)
 	var path []Object
 
-	for u == nil {
+	var u Type
+	for rhs := Type(n); u == nil; {
 		switch t := rhs.(type) {
 		case nil:
 			u = Typ[Invalid]
@@ -608,6 +607,8 @@ func (n *Named) under() Type {
 
 		case *Named:
 			if i, ok := seen[t]; ok {
+				// Note: This code may only be called during type checking,
+				//       hence n.check != nil.
 				n.check.cycleError(path[i:], firstInSrc(path[i:]))
 				u = Typ[Invalid]
 				break
@@ -635,13 +636,11 @@ func (n *Named) under() Type {
 		}
 	}
 
-	// go back up the chain
+	// set underlying for all Named types in the chain
 	for t := range seen {
 		t.underlying = u
 		t.setState(underlying)
 	}
-
-	return u
 }
 
 func (n *Named) lookupMethod(pkg *Package, name string, foldCase bool) (int, *Func) {
diff --git a/src/go/types/named.go b/src/go/types/named.go
index 35ca325db2554d..5c5c837987539c 100644
--- a/src/go/types/named.go
+++ b/src/go/types/named.go
@@ -338,7 +338,7 @@ func (n *Named) cleanup() {
 	// Instances can have a nil underlying at the end of type checking — they
 	// will lazily expand it as needed. All other types must have one.
 	if n.inst == nil {
-		n.resolve().under()
+		n.Underlying()
 	}
 	n.check = nil
 }
@@ -565,7 +565,8 @@ func (n *Named) Underlying() Type {
 		}
 	}
 
-	return n.under()
+	n.resolveUnderlying()
+	return n.underlying
 }
 
 func (t *Named) String() string { return TypeString(t, nil) }
@@ -576,7 +577,7 @@ func (t *Named) String() string { return TypeString(t, nil) }
 // TODO(rfindley): reorganize the loading and expansion methods under this
 // heading.
 
-// under returns the (possibly expanded) underlying type of n.
+// resolveUnderlying computes the underlying type of n.
 //
 // It does so by following RHS type chains. If a type literal is found, each
 // named type in the chain has its underlying set to that type. Aliases are
@@ -584,24 +585,22 @@ func (t *Named) String() string { return TypeString(t, nil) }
 //
 // This function also checks for instantiated layout cycles, which are
 // reachable only in the case where resolve() expanded an instantiated
-// type which became self-referencing without indirection. If such a
-// cycle is found, the result is Typ[Invalid]; if n.check != nil, the
-// cycle is also reported.
-func (n *Named) under() Type {
+// type which became self-referencing without indirection.
+// If such a cycle is found, the underlying type is set to Typ[Invalid]
+// and a cycle is reported.
+func (n *Named) resolveUnderlying() {
 	assert(n.stateHas(resolved))
 
 	// optimization for likely case
 	if n.stateHas(underlying) {
-		return n.underlying
+		return
 	}
 
-	var rhs Type = n
-	var u Type
-
 	seen := make(map[*Named]int)
 	var path []Object
 
-	for u == nil {
+	var u Type
+	for rhs := Type(n); u == nil; {
 		switch t := rhs.(type) {
 		case nil:
 			u = Typ[Invalid]
@@ -611,6 +610,8 @@ func (n *Named) under() Type {
 
 		case *Named:
 			if i, ok := seen[t]; ok {
+				// Note: This code may only be called during type checking,
+				//       hence n.check != nil.
 				n.check.cycleError(path[i:], firstInSrc(path[i:]))
 				u = Typ[Invalid]
 				break
@@ -638,13 +639,11 @@ func (n *Named) under() Type {
 		}
 	}
 
-	// go back up the chain
+	// set underlying for all Named types in the chain
 	for t := range seen {
 		t.underlying = u
 		t.setState(underlying)
 	}
-
-	return u
 }
 
 func (n *Named) lookupMethod(pkg *Package, name string, foldCase bool) (int, *Func) {

From 5a42af7f6c9ba057171d8a5af6f4b721b8eff10a Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Mon, 20 Oct 2025 10:25:23 -0700
Subject: [PATCH 226/229] go/types, types2: in resolveUnderlying, only compute
 path when needed

When following a RHS chain, the (TypeName) Object path is only needed
when there is a cycle (i.e., an error), in which case we can be slow.
Rather than always compute the path, only compute it in the error case.
In the same vain, allocate the seen map lazily, only when needed.

This code could use a test (it doesn't seem to be encountered by our
test suite), but I haven't found a case to provoke the error yet.

Change-Id: Iff6313394442a251adc56580f746928ec13450fd
Reviewed-on: https://go-review.googlesource.com/c/go/+/712321
Auto-Submit: Robert Griesemer 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Mark Freeman 
Reviewed-by: Robert Griesemer 
---
 src/cmd/compile/internal/types2/named.go | 16 +++++++++++-----
 src/go/types/named.go                    | 16 +++++++++++-----
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/src/cmd/compile/internal/types2/named.go b/src/cmd/compile/internal/types2/named.go
index 856f33028a41a1..99e27434840bed 100644
--- a/src/cmd/compile/internal/types2/named.go
+++ b/src/cmd/compile/internal/types2/named.go
@@ -593,9 +593,7 @@ func (n *Named) resolveUnderlying() {
 		return
 	}
 
-	seen := make(map[*Named]int)
-	var path []Object
-
+	var seen map[*Named]int // allocated lazily
 	var u Type
 	for rhs := Type(n); u == nil; {
 		switch t := rhs.(type) {
@@ -607,9 +605,15 @@ func (n *Named) resolveUnderlying() {
 
 		case *Named:
 			if i, ok := seen[t]; ok {
+				// compute cycle path
+				path := make([]Object, len(seen))
+				for t, j := range seen {
+					path[j] = t.obj
+				}
+				path = path[i:]
 				// Note: This code may only be called during type checking,
 				//       hence n.check != nil.
-				n.check.cycleError(path[i:], firstInSrc(path[i:]))
+				n.check.cycleError(path, firstInSrc(path))
 				u = Typ[Invalid]
 				break
 			}
@@ -625,8 +629,10 @@ func (n *Named) resolveUnderlying() {
 				break
 			}
 
+			if seen == nil {
+				seen = make(map[*Named]int)
+			}
 			seen[t] = len(seen)
-			path = append(path, t.obj)
 
 			assert(t.fromRHS != nil || t.allowNilRHS)
 			rhs = t.fromRHS
diff --git a/src/go/types/named.go b/src/go/types/named.go
index 5c5c837987539c..b436d073e6dfa9 100644
--- a/src/go/types/named.go
+++ b/src/go/types/named.go
@@ -596,9 +596,7 @@ func (n *Named) resolveUnderlying() {
 		return
 	}
 
-	seen := make(map[*Named]int)
-	var path []Object
-
+	var seen map[*Named]int // allocated lazily
 	var u Type
 	for rhs := Type(n); u == nil; {
 		switch t := rhs.(type) {
@@ -610,9 +608,15 @@ func (n *Named) resolveUnderlying() {
 
 		case *Named:
 			if i, ok := seen[t]; ok {
+				// compute cycle path
+				path := make([]Object, len(seen))
+				for t, j := range seen {
+					path[j] = t.obj
+				}
+				path = path[i:]
 				// Note: This code may only be called during type checking,
 				//       hence n.check != nil.
-				n.check.cycleError(path[i:], firstInSrc(path[i:]))
+				n.check.cycleError(path, firstInSrc(path))
 				u = Typ[Invalid]
 				break
 			}
@@ -628,8 +632,10 @@ func (n *Named) resolveUnderlying() {
 				break
 			}
 
+			if seen == nil {
+				seen = make(map[*Named]int)
+			}
 			seen[t] = len(seen)
-			path = append(path, t.obj)
 
 			assert(t.fromRHS != nil || t.allowNilRHS)
 			rhs = t.fromRHS

From d09a8c8ef473ba51244d6da9118b956bedb1b20d Mon Sep 17 00:00:00 2001
From: Robert Griesemer 
Date: Tue, 21 Oct 2025 15:04:46 -0700
Subject: [PATCH 227/229] go/types, types2: simplify locking in
 Named.resolveUnderlying

Avoid calling Named.resolveUnderlying in the first place (there
is only one caller) if Named.underlying exists already.

In Named.resolveUnderlying remove initial atomic check because
of the check in Named.Underlying. Also, remove a 2nd atomic
check after acquiring the lock as it likely won't help much.

Change-Id: Ife87218fa2549d0903a10218f4dd7a70f85d6c7c
Reviewed-on: https://go-review.googlesource.com/c/go/+/713521
Auto-Submit: Robert Griesemer 
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Robert Griesemer 
Reviewed-by: Mark Freeman 
---
 src/cmd/compile/internal/types2/named.go | 20 ++++++++------------
 src/go/types/named.go                    | 20 ++++++++------------
 2 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/src/cmd/compile/internal/types2/named.go b/src/cmd/compile/internal/types2/named.go
index 99e27434840bed..26be3104b8c0bb 100644
--- a/src/cmd/compile/internal/types2/named.go
+++ b/src/cmd/compile/internal/types2/named.go
@@ -562,7 +562,10 @@ func (n *Named) Underlying() Type {
 		}
 	}
 
-	n.resolveUnderlying()
+	if !n.stateHas(underlying) {
+		n.resolveUnderlying()
+	}
+
 	return n.underlying
 }
 
@@ -588,11 +591,6 @@ func (t *Named) String() string { return TypeString(t, nil) }
 func (n *Named) resolveUnderlying() {
 	assert(n.stateHas(resolved))
 
-	// optimization for likely case
-	if n.stateHas(underlying) {
-		return
-	}
-
 	var seen map[*Named]int // allocated lazily
 	var u Type
 	for rhs := Type(n); u == nil; {
@@ -618,12 +616,7 @@ func (n *Named) resolveUnderlying() {
 				break
 			}
 
-			// acquire the lock without checking; performance is probably fine
-			t.resolve()
-			t.mu.Lock()
-			defer t.mu.Unlock()
-
-			// t.underlying might have been set while we were locking
+			// avoid acquiring the lock if we can
 			if t.stateHas(underlying) {
 				u = t.underlying
 				break
@@ -634,6 +627,9 @@ func (n *Named) resolveUnderlying() {
 			}
 			seen[t] = len(seen)
 
+			t.resolve()
+			t.mu.Lock()
+			defer t.mu.Unlock()
 			assert(t.fromRHS != nil || t.allowNilRHS)
 			rhs = t.fromRHS
 
diff --git a/src/go/types/named.go b/src/go/types/named.go
index b436d073e6dfa9..79f6fc6a494160 100644
--- a/src/go/types/named.go
+++ b/src/go/types/named.go
@@ -565,7 +565,10 @@ func (n *Named) Underlying() Type {
 		}
 	}
 
-	n.resolveUnderlying()
+	if !n.stateHas(underlying) {
+		n.resolveUnderlying()
+	}
+
 	return n.underlying
 }
 
@@ -591,11 +594,6 @@ func (t *Named) String() string { return TypeString(t, nil) }
 func (n *Named) resolveUnderlying() {
 	assert(n.stateHas(resolved))
 
-	// optimization for likely case
-	if n.stateHas(underlying) {
-		return
-	}
-
 	var seen map[*Named]int // allocated lazily
 	var u Type
 	for rhs := Type(n); u == nil; {
@@ -621,12 +619,7 @@ func (n *Named) resolveUnderlying() {
 				break
 			}
 
-			// acquire the lock without checking; performance is probably fine
-			t.resolve()
-			t.mu.Lock()
-			defer t.mu.Unlock()
-
-			// t.underlying might have been set while we were locking
+			// avoid acquiring the lock if we can
 			if t.stateHas(underlying) {
 				u = t.underlying
 				break
@@ -637,6 +630,9 @@ func (n *Named) resolveUnderlying() {
 			}
 			seen[t] = len(seen)
 
+			t.resolve()
+			t.mu.Lock()
+			defer t.mu.Unlock()
 			assert(t.fromRHS != nil || t.allowNilRHS)
 			rhs = t.fromRHS
 

From 557b4d6e0f9de96ce9718f89773f14e6e1b14760 Mon Sep 17 00:00:00 2001
From: redteampanda-ng <31235211+redteampanda-ng@users.noreply.github.com>
Date: Wed, 22 Oct 2025 06:38:55 +0000
Subject: [PATCH 228/229] comment: change slice to string in function
 comment/help

Comment is outdated, it should say a string is returned

Change-Id: I7d40135aac22845dbc1f91e02e5776cc7d58eda7
GitHub-Last-Rev: 08ee556f0803dc0e2a765d431ac10758b4f26146
GitHub-Pull-Request: golang/go#75980
Reviewed-on: https://go-review.googlesource.com/c/go/+/713040
LUCI-TryBot-Result: Go LUCI 
Reviewed-by: Keith Randall 
Reviewed-by: Robert Griesemer 
Auto-Submit: Robert Griesemer 
Reviewed-by: Keith Randall 
---
 src/strings/strings.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/strings/strings.go b/src/strings/strings.go
index 1efd00d5f09c8a..80cea67d626d2e 100644
--- a/src/strings/strings.go
+++ b/src/strings/strings.go
@@ -1085,8 +1085,9 @@ func trimRightUnicode(s, cutset string) string {
 	return s
 }
 
-// TrimSpace returns a slice of the string s, with all leading
-// and trailing white space removed, as defined by Unicode.
+// TrimSpace returns a slice (substring) of the string s,
+// with all leading and trailing white space removed,
+// as defined by Unicode.
 func TrimSpace(s string) string {
 	// Fast path for ASCII: look for the first ASCII non-space byte.
 	for lo, c := range []byte(s) {

From 78e12634b50c24181d11f5e53aa1eacc509e7c8d Mon Sep 17 00:00:00 2001
From: Ariel Otilibili 
Date: Wed, 22 Oct 2025 18:55:35 +0200
Subject: [PATCH 229/229] runtime/cgo: improve error messages after ptr panic

This commit improves the error messages after panics due to the
sharing of an unpinned Go pointer (or a pointer to an unpinned Go
pointer) between Go and C.

This occurs when it is:
1. returned from Go to C (through cgoCheckResult)
2. passed as argument to a C function (through cgoCheckPointer).

An unpinned Go pointer refers to a memory location that might be moved or
freed by the garbage collector.

Therefore:

- change the signature of cgoCheckArg (it does the real work behind
  cgoCheckResult and cgoCheckPointer)
- change the signature of cgoCheckUnknownPointer (called by cgoCheckArg
  for checking unexpected pointers)
- introduce cgoFormatErr (it formats an error message with the caller name)
- update the cgo pointer tests (add new tests, and a field errTextRegexp
  to the struct ptrTest)
- remove an unused assignment in TestPointerChecks.

1. cgoCheckResult

When an unpinned Go pointer (or a pointer to an unpinned Go pointer) is
returned from Go to C,

> package main
>
> import (
>         "C"
> )
>
> //export foo
> func foo() map[int]int {
>         return map[int]int{0: 1,}
> }

This error shows up at runtime:

> panic: runtime error: cgo result is unpinned Go pointer or points to unpinned Go pointer
>
> goroutine 17 [running, locked to thread]:
> panic({0x78ac36001d40?, 0xc000194000?})
>         /usr/lib/go/src/runtime/panic.go:802 +0x168
> runtime.cgoCheckArg(0x78ac36002f40, 0xc000190000, 0xd8?, 0x0, {0x78ac35fdda62, 0x42})
>         /usr/lib/go/src/runtime/cgocall.go:628 +0x4c5
> runtime.cgoCheckResult({0x78ac36002f40, 0xc000190000})
>         /usr/lib/go/src/runtime/cgocall.go:795 +0x4b
> _cgoexp_1c29bd2c0b96_foo(0x7fffc16d87b0)
>         _cgo_gotypes.go:46 +0x6f
> runtime.cgocallbackg1(0x78ac35fd4d20, 0x7fffc16d87b0, 0x0)
>         /usr/lib/go/src/runtime/cgocall.go:446 +0x289
> runtime.cgocallbackg(0x78ac35fd4d20, 0x7fffc16d87b0, 0x0)
>         /usr/lib/go/src/runtime/cgocall.go:350 +0x132
> runtime.cgocallbackg(0x78ac35fd4d20, 0x7fffc16d87b0, 0x0)
>         :1 +0x2b
> runtime.cgocallback(0x0, 0x0, 0x0)
>         /usr/lib/go/src/runtime/asm_amd64.s:1082 +0xcd
> runtime.goexit({})
>         /usr/lib/go/src/runtime/asm_amd64.s:1693 +0x1

_cgoexp_1c29bd2c0b96_foo is the faulty caller; it is not obvious to
find it in the stack trace. Moreover the error does say which kind of
pointer caused the panic; for instance, a Go map.

Retrieve caller name and pointer kind; use them in the error message:

> panic: runtime error: result of cgo function foo is unpinned Go map or points to unpinned Go map
>
> goroutine 17 [running, locked to thread]:
> panic({0x76f2fd69b3c0?, 0x1fba8c79c000?})
>         /mnt/go/src/runtime/panic.go:877 +0x16f
> runtime.cgoCheckArg(0x76f2fd69c5c0, 0x1fba8c790000, 0x0?, 0x0, 0x1)
>         /mnt/go/src/runtime/cgocall.go:631 +0x499
> runtime.cgoCheckResult({0x76f2fd69c5c0, 0x1fba8c790000})
>         /mnt/go/src/runtime/cgocall.go:798 +0x45
> _cgoexp_1c29bd2c0b96_foo(0x7ffd0803b8c0)
>         _cgo_gotypes.go:46 +0x6f
> runtime.cgocallbackg1(0x76f2fd667680, 0x7ffd0803b8c0, 0x0)
>         /mnt/go/src/runtime/cgocall.go:446 +0x289
> runtime.cgocallbackg(0x76f2fd667680, 0x7ffd0803b8c0, 0x0)
>         /mnt/go/src/runtime/cgocall.go:350 +0x132
> runtime.cgocallbackg(0x76f2fd667680, 0x7ffd0803b8c0, 0x0)
>         :1 +0x2b
> runtime.cgocallback(0x0, 0x0, 0x0)
>         /mnt/go/src/runtime/asm_amd64.s:1101 +0xcd
> runtime.goexit({})
>         /mnt/go/src/runtime/asm_amd64.s:1712 +0x1

2. cgoCheckPointer

When an unpinned Go pointer (or a pointer to an unpinned Go pointer) is
passed to a C function,

> package main
>
> /*
> #include 
> void foo(void *bar) {}
> */
> import "C"
> import "unsafe"
>
> func main() {
>         m := map[int]int{0: 1,}
>         C.foo(unsafe.Pointer(&m))
> }

This error shows up at runtime:

> panic: runtime error: cgo argument has Go pointer to unpinned Go pointer
>
> goroutine 1 [running]:
> main.main.func1(...)
>         /mnt/chexit/cgomap.go:12
> main.main()
>         /mnt/chexit/cgomap.go:12 +0x91
> exit status 2

Retrieve callee name and pointer kind; use them in the error message.

> panic: runtime error: cgo argument of function main.main.func1 has Go pointer to unpinned Go map
>
> goroutine 1 [running]:
> main.main.func1(...)
>         /mnt/chexit/cgomap.go:12
> main.main()
>         /mnt/chexit/cgomap.go:12 +0x9b
> exit status 2

Link: https://pkg.go.dev/cmd/cgo#hdr-Passing_pointers
Suggested-by: Ian Lance Taylor 
Fixes #75856
---
 src/cmd/cgo/internal/testerrors/ptr_test.go | 50 ++++++++---
 src/runtime/cgocall.go                      | 96 ++++++++++++++++++---
 2 files changed, 122 insertions(+), 24 deletions(-)

diff --git a/src/cmd/cgo/internal/testerrors/ptr_test.go b/src/cmd/cgo/internal/testerrors/ptr_test.go
index beba0d26ac1818..3eb555ec840b73 100644
--- a/src/cmd/cgo/internal/testerrors/ptr_test.go
+++ b/src/cmd/cgo/internal/testerrors/ptr_test.go
@@ -14,6 +14,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"slices"
 	"strings"
 	"sync/atomic"
@@ -24,15 +25,16 @@ var tmp = flag.String("tmp", "", "use `dir` for temporary files and do not clean
 
 // ptrTest is the tests without the boilerplate.
 type ptrTest struct {
-	name      string   // for reporting
-	c         string   // the cgo comment
-	c1        string   // cgo comment forced into non-export cgo file
-	imports   []string // a list of imports
-	support   string   // supporting functions
-	body      string   // the body of the main function
-	extra     []extra  // extra files
-	fail      bool     // whether the test should fail
-	expensive bool     // whether the test requires the expensive check
+	name          string   // for reporting
+	c             string   // the cgo comment
+	c1            string   // cgo comment forced into non-export cgo file
+	imports       []string // a list of imports
+	support       string   // supporting functions
+	body          string   // the body of the main function
+	extra         []extra  // extra files
+	fail          bool     // whether the test should fail
+	expensive     bool     // whether the test requires the expensive check
+	errTextRegexp string   // error text regexp; if empty, use the pattern `.*unpinned Go.*`
 }
 
 type extra struct {
@@ -489,6 +491,27 @@ var ptrTests = []ptrTest{
 		body:    `i := 0; a := &[2]unsafe.Pointer{nil, unsafe.Pointer(&i)}; C.f45(&a[0])`,
 		fail:    true,
 	},
+	{
+		// Passing a Go map as argument to C.
+		name:          "argmap",
+		c:             `void f46(void* p) {}`,
+		imports:       []string{"unsafe"},
+		body:          `m := map[int]int{0: 1,}; C.f46(unsafe.Pointer(&m))`,
+		fail:          true,
+		errTextRegexp: `.*cgo argument of function .*argmap.*has Go pointer to unpinned Go map.*`,
+	},
+	{
+		// Returning a Go map to C.
+		name: "retmap",
+		c:    `extern void f47();`,
+		support: `//export GoMap47
+		          func GoMap47() map[int]int { return map[int]int{0: 1,} }`,
+		body: `C.f47()`,
+		c1: `extern void* GoMap47();
+		     void f47() { GoMap47(); }`,
+		fail:          true,
+		errTextRegexp: `.*cgo function GoMap47 is unpinned Go map or points to unpinned Go map.*`,
+	},
 }
 
 func TestPointerChecks(t *testing.T) {
@@ -519,7 +542,6 @@ func TestPointerChecks(t *testing.T) {
 	// after testOne finishes.
 	var pending int32
 	for _, pt := range ptrTests {
-		pt := pt
 		t.Run(pt.name, func(t *testing.T) {
 			atomic.AddInt32(&pending, +1)
 			defer func() {
@@ -690,11 +712,17 @@ func testOne(t *testing.T, pt ptrTest, exe, exe2 string) {
 	}
 
 	buf, err := runcmd(cgocheck)
+
+	var pattern string = pt.errTextRegexp
+	if pt.errTextRegexp == "" {
+		pattern = `.*unpinned Go.*`
+	}
+
 	if pt.fail {
 		if err == nil {
 			t.Logf("%s", buf)
 			t.Fatalf("did not fail as expected")
-		} else if !bytes.Contains(buf, []byte("Go pointer")) {
+		} else if ok, _ := regexp.Match(pattern, buf); !ok {
 			t.Logf("%s", buf)
 			t.Fatalf("did not print expected error (failed with %v)", err)
 		}
diff --git a/src/runtime/cgocall.go b/src/runtime/cgocall.go
index 18e1dc8bafc4aa..3147f337aade01 100644
--- a/src/runtime/cgocall.go
+++ b/src/runtime/cgocall.go
@@ -591,15 +591,18 @@ func cgoCheckPointer(ptr any, arg any) {
 	cgoCheckArg(t, ep.data, !t.IsDirectIface(), top, cgoCheckPointerFail)
 }
 
-const cgoCheckPointerFail = "cgo argument has Go pointer to unpinned Go pointer"
-const cgoResultFail = "cgo result is unpinned Go pointer or points to unpinned Go pointer"
+type cgoErrorMsg int
+const (
+	cgoCheckPointerFail cgoErrorMsg = iota
+	cgoResultFail
+)
 
 // cgoCheckArg is the real work of cgoCheckPointer. The argument p
 // is either a pointer to the value (of type t), or the value itself,
 // depending on indir. The top parameter is whether we are at the top
 // level, where Go pointers are allowed. Go pointers to pinned objects are
 // allowed as long as they don't reference other unpinned pointers.
-func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
+func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg cgoErrorMsg) {
 	if !t.Pointers() || p == nil {
 		// If the type has no pointers there is nothing to do.
 		return
@@ -625,7 +628,7 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
 		// These types contain internal pointers that will
 		// always be allocated in the Go heap. It's never OK
 		// to pass them to C.
-		panic(errorString(msg))
+		panic(cgoFormatErr(msg, t.Kind()))
 	case abi.Func:
 		if indir {
 			p = *(*unsafe.Pointer)(p)
@@ -633,7 +636,7 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
 		if !cgoIsGoPointer(p) {
 			return
 		}
-		panic(errorString(msg))
+		panic(cgoFormatErr(msg, t.Kind()))
 	case abi.Interface:
 		it := *(**_type)(p)
 		if it == nil {
@@ -643,14 +646,14 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
 		// constant. A type not known at compile time will be
 		// in the heap and will not be OK.
 		if inheap(uintptr(unsafe.Pointer(it))) {
-			panic(errorString(msg))
+			panic(cgoFormatErr(msg, t.Kind()))
 		}
 		p = *(*unsafe.Pointer)(add(p, goarch.PtrSize))
 		if !cgoIsGoPointer(p) {
 			return
 		}
 		if !top && !isPinned(p) {
-			panic(errorString(msg))
+			panic(cgoFormatErr(msg, t.Kind()))
 		}
 		cgoCheckArg(it, p, !it.IsDirectIface(), false, msg)
 	case abi.Slice:
@@ -661,7 +664,7 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
 			return
 		}
 		if !top && !isPinned(p) {
-			panic(errorString(msg))
+			panic(cgoFormatErr(msg, t.Kind()))
 		}
 		if !st.Elem.Pointers() {
 			return
@@ -676,7 +679,7 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
 			return
 		}
 		if !top && !isPinned(ss.str) {
-			panic(errorString(msg))
+			panic(cgoFormatErr(msg, t.Kind()))
 		}
 	case abi.Struct:
 		st := (*structtype)(unsafe.Pointer(t))
@@ -705,7 +708,7 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
 			return
 		}
 		if !top && !isPinned(p) {
-			panic(errorString(msg))
+			panic(cgoFormatErr(msg, t.Kind()))
 		}
 
 		cgoCheckUnknownPointer(p, msg)
@@ -716,7 +719,7 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool, msg string) {
 // memory. It checks whether that Go memory contains any other
 // pointer into unpinned Go memory. If it does, we panic.
 // The return values are unused but useful to see in panic tracebacks.
-func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) (base, i uintptr) {
+func cgoCheckUnknownPointer(p unsafe.Pointer, msg cgoErrorMsg) (base, i uintptr) {
 	if inheap(uintptr(p)) {
 		b, span, _ := findObject(uintptr(p), 0, 0)
 		base = b
@@ -731,7 +734,7 @@ func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) (base, i uintptr) {
 			}
 			pp := *(*unsafe.Pointer)(unsafe.Pointer(addr))
 			if cgoIsGoPointer(pp) && !isPinned(pp) {
-				panic(errorString(msg))
+				panic(cgoFormatErr(msg, abi.Pointer))
 			}
 		}
 		return
@@ -741,7 +744,7 @@ func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) (base, i uintptr) {
 		if cgoInRange(p, datap.data, datap.edata) || cgoInRange(p, datap.bss, datap.ebss) {
 			// We have no way to know the size of the object.
 			// We have to assume that it might contain a pointer.
-			panic(errorString(msg))
+			panic(cgoFormatErr(msg, abi.Pointer))
 		}
 		// In the text or noptr sections, we know that the
 		// pointer does not point to a Go pointer.
@@ -794,3 +797,70 @@ func cgoCheckResult(val any) {
 	t := ep._type
 	cgoCheckArg(t, ep.data, !t.IsDirectIface(), false, cgoResultFail)
 }
+
+// cgoFormatErr is called to format an error message with the caller name.
+func cgoFormatErr(error cgoErrorMsg, kind abi.Kind) errorString {
+	var msg, kindname string
+	var cgoFunction string = "unknown"
+	var offset int
+
+	// We expect one of these abi.Kind from cgoCheckArg
+	switch kind {
+	case abi.Chan:
+		kindname = "channel"
+	case abi.Func:
+		kindname = "function"
+	case abi.Interface:
+		kindname = "interface"
+	case abi.Map:
+		kindname = "map"
+	case abi.Pointer:
+		kindname = "pointer"
+	case abi.Slice:
+		kindname = "slice"
+	case abi.String:
+		kindname = "string"
+	case abi.Struct:
+		kindname = "struct"
+	case abi.UnsafePointer:
+		kindname = "unsafe pointer"
+	default:
+		kindname = "pointer"
+	}
+
+	// The cgo function name might need an offset to be obtained
+	if error == cgoResultFail {
+		offset = 21
+	}
+
+	// Relatively to cgoFormatErr, this is the stack frame:
+	// 0. cgoFormatErr
+	// 1. cgoCheckArg or cgoCheckUnknownPointer
+	// 2. cgoCheckPointer or cgoCheckResult
+	// 3. cgo function
+	pc, _, _, ok := Caller(3)
+	if ok {
+		function := FuncForPC(pc)
+
+		if function != nil {
+			// Expected format of cgo function name:
+			// - caller: _cgoexp_3c910ddb72c4_foo
+			// - callee: Module.Function.funcX
+			if offset > len(function.Name()) {
+				cgoFunction = function.Name()
+			} else {
+				cgoFunction = function.Name()[offset:]
+			}
+		}
+	}
+
+	if error == cgoResultFail {
+		msg = "result of cgo function " + cgoFunction
+		msg += " is unpinned Go " + kindname + " or points to unpinned Go " + kindname
+	} else if error == cgoCheckPointerFail {
+		msg = "cgo argument of function " + cgoFunction
+		msg += " has Go pointer to unpinned Go " + kindname
+	}
+
+	return errorString(msg)
+}