Rollup merge of #125880 - Zalathar:demangler, r=oli-obk

Remove `src/tools/rust-demangler`

`rust-demangler` is a small binary that reads a list of mangled symbols from stdin, demangles them (using the `rustc-demangle` library crate), and prints the demangled symbols to stdout.

It was added as part of the initial implementation of coverage instrumentation in 2020/2021, so that coverage tests could pass it to `llvm-cov --Xdemangler` when generating coverage reports. It has been largely untouched since then.

As of #125816 it is no longer used by coverage tests, and has no remaining in-tree uses.

There is code in bootstrap to build and package the demangler, but it's unclear where the resulting binaries actually end up, or whether there's any reasonable way for `rustup` users to obtain them.

---

For users needing a command-line demangler, `rustfilt` exists and is more actively maintained. It's also quite easy to use the `rustc-demangle` library to build a custom command-line demangler if necessary, with only a few lines of code.

The tool's name (`rust-demangler`) is easily confused with the name of the library crate `rustc-demangle`, so removing the tool will eliminate that confusion. There also doesn't appear to be much reason to use `rust-demangler` over `rustfilt`.

---

This PR therefore removes the tool, and removes all of its associated code from bootstrap.

MCP filed: rust-lang/compiler-team#754

Author: fmease

Cargo.lock

@@ -3479,14 +3479,6 @@ dependencies = [
  "wasmparser",
 ]
 
-[[package]]
-name = "rust-demangler"
-version = "0.0.1"
-dependencies = [
- "regex",
- "rustc-demangle",
-]
-
 [[package]]
 name = "rustbook"
 version = "0.1.0"

Cargo.toml

@@ -23,7 +23,6 @@ members = [
   "src/tools/remote-test-client",
   "src/tools/remote-test-server",
   "src/tools/rust-installer",
-  "src/tools/rust-demangler",
   "src/tools/rustdoc",
   "src/tools/rls",
   "src/tools/rustfmt",

config.example.toml

@@ -321,8 +321,7 @@
 #
 # If `extended = false`, the only one of these built by default is rustdoc.
 #
-# If `extended = true`, they're all included, with the exception of
-# rust-demangler which additionally requires `profiler = true` to be set.
+# If `extended = true`, they are all included.
 #
 # If any enabled tool fails to build, the installation fails.
 #tools = [
@@ -334,7 +333,6 @@
 #    "rust-analyzer-proc-macro-srv",
 #    "analysis",
 #    "src",
-#    "rust-demangler",  # if profiler = true
 #]
 
 # Verbosity level: 0 == not verbose, 1 == verbose, 2 == very verbose, 3 == print environment variables on each rustc invocation

src/bootstrap/src/core/build_steps/clippy.rs

@@ -322,7 +322,6 @@ lint_any!(
     RemoteTestServer, "src/tools/remote-test-server", "remote-test-server";
     Rls, "src/tools/rls", "rls";
     RustAnalyzer, "src/tools/rust-analyzer", "rust-analyzer";
-    RustDemangler, "src/tools/rust-demangler", "rust-demangler";
     Rustdoc, "src/tools/rustdoc", "clippy";
     Rustfmt, "src/tools/rustfmt", "rustfmt";
     RustInstaller, "src/tools/rust-installer", "rust-installer";

src/bootstrap/src/core/build_steps/dist.rs

@@ -1459,62 +1459,6 @@ impl Step for Rustfmt {
     }
 }
 
-#[derive(Debug, PartialOrd, Ord, Clone, Hash, PartialEq, Eq)]
-pub struct RustDemangler {
-    pub compiler: Compiler,
-    pub target: TargetSelection,
-}
-
-impl Step for RustDemangler {
-    type Output = Option<GeneratedTarball>;
-    const DEFAULT: bool = true;
-    const ONLY_HOSTS: bool = true;
-
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        // While other tools use `should_build_extended_tool` to decide whether to be run by
-        // default or not, `rust-demangler` must be build when *either* it's enabled as a tool like
-        // the other ones or if `profiler = true`. Because we don't know the target at this stage
-        // we run the step by default when only `extended = true`, and decide whether to actually
-        // run it or not later.
-        let default = run.builder.config.extended;
-        run.alias("rust-demangler").default_condition(default)
-    }
-
-    fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(RustDemangler {
-            compiler: run.builder.compiler_for(
-                run.builder.top_stage,
-                run.builder.config.build,
-                run.target,
-            ),
-            target: run.target,
-        });
-    }
-
-    fn run(self, builder: &Builder<'_>) -> Option<GeneratedTarball> {
-        let compiler = self.compiler;
-        let target = self.target;
-
-        // Only build this extended tool if explicitly included in `tools`, or if `profiler = true`
-        let condition = should_build_extended_tool(builder, "rust-demangler")
-            || builder.config.profiler_enabled(target);
-        if builder.config.extended && !condition {
-            return None;
-        }
-
-        let rust_demangler =
-            builder.ensure(tool::RustDemangler { compiler, target, extra_features: Vec::new() });
-
-        // Prepare the image directory
-        let mut tarball = Tarball::new(builder, "rust-demangler", &target.triple);
-        tarball.set_overlay(OverlayKind::RustDemangler);
-        tarball.is_preview(true);
-        tarball.add_file(rust_demangler, "bin", 0o755);
-        tarball.add_legal_and_readme_to("share/doc/rust-demangler");
-        Some(tarball.generate())
-    }
-}
-
 #[derive(Debug, PartialOrd, Ord, Clone, Hash, PartialEq, Eq)]
 pub struct Extended {
     stage: u32,
@@ -1572,7 +1516,6 @@ impl Step for Extended {
 
         add_component!("rust-docs" => Docs { host: target });
         add_component!("rust-json-docs" => JsonDocs { host: target });
-        add_component!("rust-demangler"=> RustDemangler { compiler, target });
         add_component!("cargo" => Cargo { compiler, target });
         add_component!("rustfmt" => Rustfmt { compiler, target });
         add_component!("rls" => Rls { compiler, target });
@@ -1636,7 +1579,7 @@ impl Step for Extended {
 
         let xform = |p: &Path| {
             let mut contents = t!(fs::read_to_string(p));
-            for tool in &["rust-demangler", "miri", "rust-docs"] {
+            for tool in &["miri", "rust-docs"] {
                 if !built_tools.contains(tool) {
                     contents = filter(&contents, tool);
                 }
@@ -1677,7 +1620,7 @@ impl Step for Extended {
             prepare("rust-analysis");
             prepare("clippy");
             prepare("rust-analyzer");
-            for tool in &["rust-docs", "rust-demangler", "miri", "rustc-codegen-cranelift"] {
+            for tool in &["rust-docs", "miri", "rustc-codegen-cranelift"] {
                 if built_tools.contains(tool) {
                     prepare(tool);
                 }
@@ -1717,8 +1660,6 @@ impl Step for Extended {
                     "rust-analyzer-preview".to_string()
                 } else if name == "clippy" {
                     "clippy-preview".to_string()
-                } else if name == "rust-demangler" {
-                    "rust-demangler-preview".to_string()
                 } else if name == "miri" {
                     "miri-preview".to_string()
                 } else if name == "rustc-codegen-cranelift" {
@@ -1738,7 +1679,7 @@ impl Step for Extended {
             prepare("cargo");
             prepare("rust-analysis");
             prepare("rust-std");
-            for tool in &["clippy", "rust-analyzer", "rust-docs", "rust-demangler", "miri"] {
+            for tool in &["clippy", "rust-analyzer", "rust-docs", "miri"] {
                 if built_tools.contains(tool) {
                     prepare(tool);
                 }
@@ -1862,25 +1803,6 @@ impl Step for Extended {
                         .arg(etc.join("msi/remove-duplicates.xsl")),
                 );
             }
-            if built_tools.contains("rust-demangler") {
-                builder.run(
-                    Command::new(&heat)
-                        .current_dir(&exe)
-                        .arg("dir")
-                        .arg("rust-demangler")
-                        .args(heat_flags)
-                        .arg("-cg")
-                        .arg("RustDemanglerGroup")
-                        .arg("-dr")
-                        .arg("RustDemangler")
-                        .arg("-var")
-                        .arg("var.RustDemanglerDir")
-                        .arg("-out")
-                        .arg(exe.join("RustDemanglerGroup.wxs"))
-                        .arg("-t")
-                        .arg(etc.join("msi/remove-duplicates.xsl")),
-                );
-            }
             if built_tools.contains("miri") {
                 builder.run(
                     Command::new(&heat)
@@ -1958,9 +1880,6 @@ impl Step for Extended {
                 if built_tools.contains("rust-docs") {
                     cmd.arg("-dDocsDir=rust-docs");
                 }
-                if built_tools.contains("rust-demangler") {
-                    cmd.arg("-dRustDemanglerDir=rust-demangler");
-                }
                 if built_tools.contains("rust-analyzer") {
                     cmd.arg("-dRustAnalyzerDir=rust-analyzer");
                 }
@@ -1987,9 +1906,6 @@ impl Step for Extended {
             if built_tools.contains("miri") {
                 candle("MiriGroup.wxs".as_ref());
             }
-            if built_tools.contains("rust-demangler") {
-                candle("RustDemanglerGroup.wxs".as_ref());
-            }
             if built_tools.contains("rust-analyzer") {
                 candle("RustAnalyzerGroup.wxs".as_ref());
             }
@@ -2031,9 +1947,6 @@ impl Step for Extended {
             if built_tools.contains("rust-analyzer") {
                 cmd.arg("RustAnalyzerGroup.wixobj");
             }
-            if built_tools.contains("rust-demangler") {
-                cmd.arg("RustDemanglerGroup.wixobj");
-            }
             if built_tools.contains("rust-docs") {
                 cmd.arg("DocsGroup.wixobj");
             }

src/bootstrap/src/core/build_steps/install.rs

@@ -265,22 +265,6 @@ install!((self, builder, _config),
             );
         }
     };
-    RustDemangler, alias = "rust-demangler", Self::should_build(_config), only_hosts: true, {
-        // NOTE: Even though `should_build` may return true for `extended` default tools,
-        // dist::RustDemangler may still return None, unless the target-dependent `profiler` config
-        // is also true, or the `tools` array explicitly includes "rust-demangler".
-        if let Some(tarball) = builder.ensure(dist::RustDemangler {
-            compiler: self.compiler,
-            target: self.target
-        }) {
-            install_sh(builder, "rust-demangler", self.compiler.stage, Some(self.target), &tarball);
-        } else {
-            builder.info(
-                &format!("skipping Install RustDemangler stage{} ({})",
-                         self.compiler.stage, self.target),
-            );
-        }
-    };
     Rustc, path = "compiler/rustc", true, only_hosts: true, {
         let tarball = builder.ensure(dist::Rustc {
             compiler: builder.compiler(builder.top_stage, self.target),

src/bootstrap/src/core/build_steps/test.rs

@@ -432,65 +432,6 @@ impl Step for Rustfmt {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub struct RustDemangler {
-    stage: u32,
-    host: TargetSelection,
-}
-
-impl Step for RustDemangler {
-    type Output = ();
-    const ONLY_HOSTS: bool = true;
-
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.path("src/tools/rust-demangler")
-    }
-
-    fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(RustDemangler { stage: run.builder.top_stage, host: run.target });
-    }
-
-    /// Runs `cargo test` for rust-demangler.
-    fn run(self, builder: &Builder<'_>) {
-        let stage = self.stage;
-        let host = self.host;
-        let compiler = builder.compiler(stage, host);
-
-        let rust_demangler = builder.ensure(tool::RustDemangler {
-            compiler,
-            target: self.host,
-            extra_features: Vec::new(),
-        });
-        let mut cargo = tool::prepare_tool_cargo(
-            builder,
-            compiler,
-            Mode::ToolRustc,
-            host,
-            "test",
-            "src/tools/rust-demangler",
-            SourceType::InTree,
-            &[],
-        );
-
-        let dir = testdir(builder, compiler.host);
-        t!(fs::create_dir_all(dir));
-
-        cargo.env("RUST_DEMANGLER_DRIVER_PATH", rust_demangler);
-        cargo.add_rustc_lib_path(builder);
-
-        run_cargo_test(
-            cargo,
-            &[],
-            &[],
-            "rust-demangler",
-            "rust-demangler",
-            compiler,
-            host,
-            builder,
-        );
-    }
-}
-
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Miri {
     target: TargetSelection,

src/bootstrap/src/core/build_steps/tool.rs

@@ -964,7 +964,6 @@ tool_extended!((self, builder),
     // But `builder.cargo` doesn't know how to handle ToolBootstrap in stages other than 0,
     // and this is close enough for now.
     Rls, "src/tools/rls", "rls", stable=true, tool_std=true;
-    RustDemangler, "src/tools/rust-demangler", "rust-demangler", stable=false, tool_std=true;
     Rustfmt, "src/tools/rustfmt", "rustfmt", stable=true, add_bins_to_sysroot = ["rustfmt", "cargo-fmt"];
 );
 

src/bootstrap/src/core/builder.rs

@@ -736,7 +736,6 @@ impl<'a> Builder<'a> {
                 tool::Rls,
                 tool::RustAnalyzer,
                 tool::RustAnalyzerProcMacroSrv,
-                tool::RustDemangler,
                 tool::Rustdoc,
                 tool::Clippy,
                 tool::CargoClippy,
@@ -774,7 +773,6 @@ impl<'a> Builder<'a> {
                 clippy::RemoteTestServer,
                 clippy::Rls,
                 clippy::RustAnalyzer,
-                clippy::RustDemangler,
                 clippy::Rustdoc,
                 clippy::Rustfmt,
                 clippy::RustInstaller,
@@ -842,7 +840,6 @@ impl<'a> Builder<'a> {
                 test::Miri,
                 test::CargoMiri,
                 test::Clippy,
-                test::RustDemangler,
                 test::CompiletestTest,
                 test::CrateRunMakeSupport,
                 test::RustdocJSStd,
@@ -903,7 +900,6 @@ impl<'a> Builder<'a> {
                 dist::Rls,
                 dist::RustAnalyzer,
                 dist::Rustfmt,
-                dist::RustDemangler,
                 dist::Clippy,
                 dist::Miri,
                 dist::LlvmTools,
@@ -930,7 +926,6 @@ impl<'a> Builder<'a> {
                 install::Cargo,
                 install::RustAnalyzer,
                 install::Rustfmt,
-                install::RustDemangler,
                 install::Clippy,
                 install::Miri,
                 install::LlvmTools,

src/bootstrap/src/utils/tarball.rs

@@ -23,7 +23,6 @@ pub(crate) enum OverlayKind {
     Clippy,
     Miri,
     Rustfmt,
-    RustDemangler,
     Rls,
     RustAnalyzer,
     RustcCodegenCranelift,
@@ -58,9 +57,6 @@ impl OverlayKind {
                 "src/tools/rustfmt/LICENSE-APACHE",
                 "src/tools/rustfmt/LICENSE-MIT",
             ],
-            OverlayKind::RustDemangler => {
-                &["src/tools/rust-demangler/README.md", "LICENSE-APACHE", "LICENSE-MIT"]
-            }
             OverlayKind::Rls => &["src/tools/rls/README.md", "LICENSE-APACHE", "LICENSE-MIT"],
             OverlayKind::RustAnalyzer => &[
                 "src/tools/rust-analyzer/README.md",
@@ -85,7 +81,6 @@ impl OverlayKind {
         match self {
             OverlayKind::Rust => builder.rust_version(),
             OverlayKind::Llvm => builder.rust_version(),
-            OverlayKind::RustDemangler => builder.release_num("rust-demangler"),
             OverlayKind::Cargo => {
                 builder.cargo_info.version(builder, &builder.release_num("cargo"))
             }