101 changes: 101 additions & 0 deletions clang/lib/CodeGen/MicrosoftCXXABI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -255,9 +255,22 @@ class MicrosoftCXXABI : public CGCXXABI {
llvm::Value *performReturnAdjustment(CodeGenFunction &CGF, llvm::Value *Ret,
const ReturnAdjustment &RA) override;

void EmitThreadLocalInitFuncs(
CodeGenModule &CGM,
ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
CXXThreadLocals,
ArrayRef<llvm::Function *> CXXThreadLocalInits,
ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) override;

bool usesThreadWrapperFunction() const override { return false; }
LValue EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF, const VarDecl *VD,
QualType LValType) override;

void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
llvm::GlobalVariable *DeclPtr,
bool PerformInit) override;
void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
llvm::Constant *Dtor, llvm::Constant *Addr) override;

// ==== Notes on array cookies =========
//
Expand Down Expand Up @@ -1711,6 +1724,94 @@ llvm::Value* MicrosoftCXXABI::InitializeArrayCookie(CodeGenFunction &CGF,
cookieSize.getQuantity());
}

static void emitGlobalDtorWithTLRegDtor(CodeGenFunction &CGF, const VarDecl &VD,
llvm::Constant *Dtor,
llvm::Constant *Addr) {
// Create a function which calls the destructor.
llvm::Constant *DtorStub = CGF.createAtExitStub(VD, Dtor, Addr);

// extern "C" int __tlregdtor(void (*f)(void));
llvm::FunctionType *TLRegDtorTy = llvm::FunctionType::get(
CGF.IntTy, DtorStub->getType(), /*IsVarArg=*/false);

llvm::Constant *TLRegDtor =
CGF.CGM.CreateRuntimeFunction(TLRegDtorTy, "__tlregdtor");
if (llvm::Function *TLRegDtorFn = dyn_cast<llvm::Function>(TLRegDtor))
TLRegDtorFn->setDoesNotThrow();

CGF.EmitNounwindRuntimeCall(TLRegDtor, DtorStub);
}

void MicrosoftCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
llvm::Constant *Dtor,
llvm::Constant *Addr) {
if (D.getTLSKind())
return emitGlobalDtorWithTLRegDtor(CGF, D, Dtor, Addr);

// The default behavior is to use atexit.
CGF.registerGlobalDtorWithAtExit(D, Dtor, Addr);
}

void MicrosoftCXXABI::EmitThreadLocalInitFuncs(
CodeGenModule &CGM,
ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *>>
CXXThreadLocals,
ArrayRef<llvm::Function *> CXXThreadLocalInits,
ArrayRef<llvm::GlobalVariable *> CXXThreadLocalInitVars) {
// This will create a GV in the .CRT$XDU section. It will point to our
// initialization function. The CRT will call all of these function
// pointers at start-up time and, eventually, at thread-creation time.
auto AddToXDU = [&CGM](llvm::Function *InitFunc) {
llvm::GlobalVariable *InitFuncPtr = new llvm::GlobalVariable(
CGM.getModule(), InitFunc->getType(), /*IsConstant=*/true,
llvm::GlobalVariable::InternalLinkage, InitFunc,
Twine(InitFunc->getName(), "$initializer$"));
InitFuncPtr->setSection(".CRT$XDU");
// This variable has discardable linkage, we have to add it to @llvm.used to
// ensure it won't get discarded.
CGM.addUsedGlobal(InitFuncPtr);
return InitFuncPtr;
};

std::vector<llvm::Function *> NonComdatInits;
for (size_t I = 0, E = CXXThreadLocalInitVars.size(); I != E; ++I) {
llvm::GlobalVariable *GV = CXXThreadLocalInitVars[I];
llvm::Function *F = CXXThreadLocalInits[I];

// If the GV is already in a comdat group, then we have to join it.
llvm::Comdat *C = GV->getComdat();

// LinkOnce and Weak linkage are lowered down to a single-member comdat
// group.
// Make an explicit group so we can join it.
if (!C && (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage())) {
C = CGM.getModule().getOrInsertComdat(GV->getName());
GV->setComdat(C);
AddToXDU(F)->setComdat(C);
} else {
NonComdatInits.push_back(F);
}
}

if (!NonComdatInits.empty()) {
llvm::FunctionType *FTy =
llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
llvm::Function *InitFunc =
CGM.CreateGlobalInitOrDestructFunction(FTy, "__tls_init",
/*TLS=*/true);
CodeGenFunction(CGM).GenerateCXXGlobalInitFunc(InitFunc, NonComdatInits);

AddToXDU(InitFunc);
}
}

LValue MicrosoftCXXABI::EmitThreadLocalVarDeclLValue(CodeGenFunction &CGF,
const VarDecl *VD,
QualType LValType) {
CGF.CGM.ErrorUnsupported(VD, "thread wrappers");
return LValue();
}

void MicrosoftCXXABI::EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
llvm::GlobalVariable *GV,
bool PerformInit) {
Expand Down
28 changes: 28 additions & 0 deletions clang/test/CodeGenCXX/ms-thread_local.cpp
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@@ -0,0 +1,28 @@
// RUN: %clang_cc1 %s -std=c++1y -triple=i686-pc-win32 -emit-llvm -o - | FileCheck %s

struct A {
A();
~A();
};

// CHECK-DAG: $"\01??$a@X@@3UA@@A" = comdat any
// CHECK-DAG: @"\01??$a@X@@3UA@@A" = linkonce_odr thread_local global %struct.A zeroinitializer, comdat $"\01??$a@X@@3UA@@A"
// CHECK-DAG: @"\01??__E?$a@X@@YAXXZ$initializer$" = internal constant void ()* @"\01??__E?$a@X@@YAXXZ", section ".CRT$XDU", comdat $"\01??$a@X@@3UA@@A"
template <typename T>
thread_local A a = A();

// CHECK-DAG: @"\01?b@@3UA@@A" = thread_local global %struct.A zeroinitializer, align 1
// CHECK-DAG: @"__tls_init$initializer$" = internal constant void ()* @__tls_init, section ".CRT$XDU"
thread_local A b;

// CHECK-LABEL: define internal void @__tls_init()
// CHECK: call void @"\01??__Eb@@YAXXZ"

thread_local A &c = b;
thread_local A &d = c;

A f() {
(void)a<void>;
(void)b;
return c;
}