Remove typed-function-references feature (#5030)

In practice typed function references will not ship before GC and is not
independently useful, so it's not necessary to have a separate feature for it.
Roll the functionality previously enabled by --enable-typed-function-references
into --enable-gc instead.

This also avoids a problem with the ongoing implementation of the new GC bottom
heap types. That change will make all ref.null instructions in Binaryen IR refer
to one of the bottom heap types. But since those bottom types are introduced in
GC, it's not valid to emit them in binaries unless unless GC is enabled. The fix
if only reference types is enabled is to emit (ref.null func) instead
of (ref.null nofunc), but that doesn't always work if typed function references
are enabled because a function type more specific than func may be required.
Getting rid of typed function references as a separate feature makes this a
nonissue.

1 files changed, 1 insertions, 2 deletions

diff --git a/src/passes/MergeSimilarFunctions.cpp b/src/passes/MergeSimilarFunctions.cpp
index 9edf327fc..38cae8059 100644
--- a/src/passes/MergeSimilarFunctions.cpp
+++ b/src/passes/MergeSimilarFunctions.cpp
@@ -202,8 +202,7 @@ struct MergeSimilarFunctions : public Pass {
 
   // Parameterize direct calls if the module supports func ref values.
   bool isCallIndirectionEnabled(Module* module) const {
-    return module->features.hasReferenceTypes() &&
-           module->features.hasTypedFunctionReferences();
+    return module->features.hasReferenceTypes() && module->features.hasGC();
   }
   bool areInEquvalentClass(Function* lhs, Function* rhs, Module* module);
   void collectEquivalentClasses(std::vector<EquivalentClass>& classes,