[PATCH] D58864: [WebAssembly] Fix crash when __wasm_call_ctor is GCd in programs containing static init/fini

[Sam Clegg via Phabricator via llvm-commits]

sbc100 created this revision.
Herald added subscribers: llvm-commits, sunfish, aheejin, jgravelle-google, dschuff.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D58864

Files:
  lld/test/wasm/init-fini-gc.ll
  lld/wasm/Writer.cpp


Index: lld/wasm/Writer.cpp
===================================================================
--- lld/wasm/Writer.cpp
+++ lld/wasm/Writer.cpp
@@ -1168,6 +1168,9 @@
 // This is then used either when creating the output linking section or to
 // synthesize the "__wasm_call_ctors" function.
 void Writer::calculateInitFunctions() {
+  if (!Config->Relocatable && !WasmSym::CallCtors->isLive())
+    return;
+
   for (ObjFile *File : Symtab->ObjectFiles) {
     const WasmLinkingData &L = File->getWasmObj()->linkingData();
     for (const WasmInitFunc &F : L.InitFunctions) {
Index: lld/test/wasm/init-fini-gc.ll
===================================================================
--- /dev/null
+++ lld/test/wasm/init-fini-gc.ll
@@ -0,0 +1,48 @@
+; RUN: llc -filetype=obj -o %t.o %s
+; RUN: wasm-ld %t.o -o %t.wasm
+; RUN: obj2yaml %t.wasm | FileCheck %s
+
+; RUN: wasm-ld %t.o -o %t.wasm
+; RUN: obj2yaml %t.wasm | FileCheck %s
+
+; RUN: wasm-ld --export=__wasm_call_ctors %t.o -o %t.export.wasm
+; RUN: obj2yaml %t.export.wasm | FileCheck %s -check-prefix=EXPORT
+
+; Test that the __wasm_call_ctor function if not referenced
+
+target triple = "wasm32-unknown-unknown"
+
+define hidden void @_start() {
+entry:
+  ret void
+}
+
+define hidden void @func1() {
+entry:
+  ret void
+}
+
+define hidden void @func2() {
+entry:
+  ret void
+}
+
+define i32 @__cxa_atexit(i32 %func, i32 %arg, i32 %dso_handle) {
+  ret i32 0
+}
+
+ at llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [
+  { i32, void ()*, i8* } { i32 1, void ()* @func1, i8* null }
+]
+
+ at llvm.global_dtors = appending global [1 x { i32, void ()*, i8* }] [
+  { i32, void ()*, i8* } { i32 1, void ()* @func2, i8* null }
+]
+
+; CHECK-NOT: __cxa_atexit
+; CHECK-NOT: __wasm_call_ctors
+
+; EXPORT: __wasm_call_ctors
+; EXPORT: func1
+; EXPORT: func2
+; EXPORT: __cxa_atexit


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