[PATCH] D40738: Don't use Wasm function sections for more than one function

[Nicholas Wilson via Phabricator via cfe-commits]

ncw created this revision.
Herald added subscribers: cfe-commits, aheejin, sbc100, dschuff, jfb.

Fixes Bugzilla https://bugs.llvm.org/show_bug.cgi?id=35467

If a Wasm function section is created with more than one symbol, WasmObjectWriter fails with the following message: "function sections must contain one function each".

Currently, if a C++ file contains multiple static initialisers, they'll all be put in the same function section, triggering the error.

I think this change here is safe - it seems to be a spurious optimisation. In fact, I'm not even sure how it's intended to optimise the output...?


Repository:
  rC Clang

https://reviews.llvm.org/D40738

Files:
  lib/Basic/Targets/OSTargets.h
  test/CodeGenCXX/static-init-wasm.cpp


Index: test/CodeGenCXX/static-init-wasm.cpp
===================================================================
--- test/CodeGenCXX/static-init-wasm.cpp
+++ test/CodeGenCXX/static-init-wasm.cpp
@@ -43,12 +43,12 @@
 
 A theA;
 
-// WEBASSEMBLY32: define internal void @__cxx_global_var_init() #3 section ".text.__startup" {
+// WEBASSEMBLY32: define internal void @__cxx_global_var_init() #3 {
 // WEBASSEMBLY32: call %struct.A* @_ZN1AC1Ev(%struct.A* @theA)
-// WEBASSEMBLY32: define internal void @_GLOBAL__sub_I_static_init_wasm.cpp() #3 section ".text.__startup" {
+// WEBASSEMBLY32: define internal void @_GLOBAL__sub_I_static_init_wasm.cpp() #3 {
 // WEBASSEMBLY32: call void @__cxx_global_var_init()
 //
-// WEBASSEMBLY64: define internal void @__cxx_global_var_init() #3 section ".text.__startup" {
+// WEBASSEMBLY64: define internal void @__cxx_global_var_init() #3 {
 // WEBASSEMBLY64: call %struct.A* @_ZN1AC1Ev(%struct.A* @theA)
-// WEBASSEMBLY64: define internal void @_GLOBAL__sub_I_static_init_wasm.cpp() #3 section ".text.__startup" {
+// WEBASSEMBLY64: define internal void @_GLOBAL__sub_I_static_init_wasm.cpp() #3 {
 // WEBASSEMBLY64: call void @__cxx_global_var_init()
Index: lib/Basic/Targets/OSTargets.h
===================================================================
--- lib/Basic/Targets/OSTargets.h
+++ lib/Basic/Targets/OSTargets.h
@@ -711,11 +711,6 @@
       Builder.defineMacro("_GNU_SOURCE");
   }
 
-  // As an optimization, group static init code together in a section.
-  const char *getStaticInitSectionSpecifier() const final {
-    return ".text.__startup";
-  }
-
 public:
   explicit WebAssemblyOSTargetInfo(const llvm::Triple &Triple,
                                    const TargetOptions &Opts)


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