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[WebAssembly] Strip threadlocal attribute from globals in single thread mode

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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
This commit is contained in:
Derek Schuff 2018-03-20 22:01:32 +00:00
parent a7f6df489f
commit 40971abb82
2 changed files with 37 additions and 2 deletions
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22
lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
View File

@ -126,6 +126,22 @@ WebAssemblyTargetMachine::getSubtargetImpl(const Function &F) const {
}
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 @@ FunctionPass *WebAssemblyPassConfig::createTargetRegisterAllocator(bool) {
//===----------------------------------------------------------------------===//
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());

17
test/CodeGen/WebAssembly/tls.ll Normal file
View File

@ -0,0 +1,17 @@
; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals -thread-model=single | FileCheck --check-prefix=SINGLE %s
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown-wasm"
; SINGLE-LABEL: address_of_tls:
define i32 @address_of_tls() {
; SINGLE: i32.const $push0=, tls
; SINGLE-NEXT: return $pop0
ret i32 ptrtoint(i32* @tls to i32)
}
; SINGLE: .type tls,@object
; SINGLE-NEXT: .section .bss.tls,"",@
; SINGLE-NEXT: .p2align 2
; SINGLE-NEXT: tls:
; SINGLE-NEXT: .int32 0
@tls = internal thread_local global i32 0