[WebAssembly] Strip threadlocal attribute from globals in single thread mode
The default thread model for wasm is single, and in this mode thread-local
global variables can be lowered identically to non-thread-local variables.
Differential Revision: https://reviews.llvm.org/D44703
llvm-svn: 328049
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
index a686e77..c006df0 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
@@ -126,6 +126,22 @@
}
namespace {
+class StripThreadLocal final : public ModulePass {
+ // The default thread model for wasm is single, where thread-local variables
+ // are identical to regular globals and should be treated the same. So this
+ // pass just converts all GlobalVariables to NotThreadLocal
+ static char ID;
+
+ public:
+ StripThreadLocal() : ModulePass(ID) {}
+ bool runOnModule(Module &M) override {
+ for (auto &GV : M.globals())
+ GV.setThreadLocalMode(GlobalValue::ThreadLocalMode::NotThreadLocal);
+ return true;
+ }
+};
+char StripThreadLocal::ID = 0;
+
/// WebAssembly Code Generator Pass Configuration Options.
class WebAssemblyPassConfig final : public TargetPassConfig {
public:
@@ -166,13 +182,15 @@
//===----------------------------------------------------------------------===//
void WebAssemblyPassConfig::addIRPasses() {
- if (TM->Options.ThreadModel == ThreadModel::Single)
+ if (TM->Options.ThreadModel == ThreadModel::Single) {
// In "single" mode, atomics get lowered to non-atomics.
addPass(createLowerAtomicPass());
- else
+ addPass(new StripThreadLocal());
+ } else {
// Expand some atomic operations. WebAssemblyTargetLowering has hooks which
// control specifically what gets lowered.
addPass(createAtomicExpandPass());
+ }
// Lower .llvm.global_dtors into .llvm_global_ctors with __cxa_atexit calls.
addPass(createWebAssemblyLowerGlobalDtors());