Update TypeUpdating for exact heap types

scripts/test/fuzzing.py

@@ -115,6 +115,7 @@
     'custom-descriptors.wast',
     # TODO: fuzzer support for exact heap types
     'exact.wast',
+    'remove-unused-types-exact.wast',
 ]
 
 

src/ir/type-updating.cpp

@@ -123,7 +123,7 @@ GlobalTypeRewriter::TypeMap GlobalTypeRewriter::rebuildTypes(
 
   // Create the temporary heap types.
   i = 0;
-  auto map = [&](HeapType type) -> HeapType {
+  auto map = [&](HeapTypeDef type) -> HeapType {
     if (auto it = typeIndices.find(type); it != typeIndices.end()) {
       return typeBuilder[it->second];
     }
@@ -226,6 +226,12 @@ void GlobalTypeRewriter::mapTypes(const TypeMap& oldToNewTypes) {
       if (iter != oldToNewTypes.end()) {
         return iter->second;
       }
+      if (type.isExact()) {
+        iter = oldToNewTypes.find(type.with(Inexact));
+        if (iter != oldToNewTypes.end()) {
+          return iter->second.with(Exact);
+        }
+      }
       return type;
     }
 

src/wasm-type.h

@@ -729,9 +729,9 @@ struct TypeBuilder {
   void setHeapType(size_t i, Array array);
 
   // Sets the heap type at index `i` to be a copy of the given heap type with
-  // its referenced HeapTypes to be replaced according to the provided mapping
+  // its referenced HeapTypeDef to be replaced according to the provided mapping
   // function.
-  template<typename F> void copyHeapType(size_t i, HeapType type, F map) {
+  template<typename F> void copyHeapType(size_t i, HeapTypeDef type, F map) {
     assert(!type.isBasic());
     if (auto super = type.getDeclaredSuperType()) {
       setSubType(i, map(*super));
@@ -750,7 +750,9 @@ struct TypeBuilder {
         return t;
       }
       assert(t.isRef());
-      return getTempRefType(map(t.getHeapType()), t.getNullability());
+      auto ht = t.getHeapType();
+      return getTempRefType(map(ht).with(ht.getExactness()),
+                            t.getNullability());
     };
     auto copyType = [&](Type t) -> Type {
       if (t.isTuple()) {
@@ -797,7 +799,7 @@ struct TypeBuilder {
 
   // Gets the temporary HeapType at index `i`. This HeapType should only be used
   // to construct temporary Types using the methods below.
-  HeapType getTempHeapType(size_t i);
+  HeapTypeDef getTempHeapType(size_t i);
 
   // Gets a temporary type or heap type for use in initializing the
   // TypeBuilder's HeapTypes. For Ref types, the HeapType may be a temporary
@@ -878,7 +880,7 @@ struct TypeBuilder {
   struct Entry {
     TypeBuilder& builder;
     size_t index;
-    operator HeapType() const { return builder.getTempHeapType(index); }
+    operator HeapTypeDef() const { return builder.getTempHeapType(index); }
     Entry& operator=(Signature signature) {
       builder.setHeapType(index, signature);
       return *this;
@@ -919,7 +921,7 @@ struct TypeBuilder {
       builder.setShared(index, share);
       return *this;
     }
-    template<typename F> Entry& copy(HeapType type, F map) {
+    template<typename F> Entry& copy(HeapTypeDef type, F map) {
       builder.copyHeapType(index, type, map);
       return *this;
     }

src/wasm/wasm-type.cpp

@@ -2278,7 +2278,7 @@ void TypeBuilder::setHeapType(size_t i, Array array) {
   impl->entries[i].set(array);
 }
 
-HeapType TypeBuilder::getTempHeapType(size_t i) {
+HeapTypeDef TypeBuilder::getTempHeapType(size_t i) {
   assert(i < size() && "index out of bounds");
   return impl->entries[i].get();
 }

test/lit/passes/remove-unused-types-exact.wast

@@ -0,0 +1,16 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; RUN: wasm-opt -all %s --closed-world --remove-unused-types -S -o - | filecheck %s
+
+;; Check that exactness is preserved through type updating and that the
+;; underlying heap types are actually updated.
+
+(module
+  (rec
+    (type $unused (struct))
+    ;; CHECK:      (type $used (struct (field (ref null $used)) (field (ref (exact $used)))))
+    (type $used (struct (field (ref null $used) (ref (exact $used)))))
+  )
+  ;; CHECK:      (global $g (ref null (exact $used)) (ref.null none))
+  (global $g (ref null (exact $used)) (ref.null none))
+)