Implement CodeGen for C++11 thread_local, following the Itanium ABI specification as discussed on cxx-abi-dev.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179858 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGCXXABI.cpp b/lib/CodeGen/CGCXXABI.cpp
index 3bf6480..68fecb2 100644
--- a/lib/CodeGen/CGCXXABI.cpp
+++ b/lib/CodeGen/CGCXXABI.cpp
@@ -259,3 +259,14 @@
ErrorUnsupportedABI(CGF, "complete object detection in ctor");
return 0;
}
+
+void CGCXXABI::EmitThreadLocalInitFuncs(
+ llvm::ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *> > Decls,
+ llvm::Function *InitFunc) {
+}
+
+LValue CGCXXABI::EmitThreadLocalDeclRefExpr(CodeGenFunction &CGF,
+ const DeclRefExpr *DRE) {
+ ErrorUnsupportedABI(CGF, "odr-use of thread_local global");
+ return LValue();
+}
diff --git a/lib/CodeGen/CGCXXABI.h b/lib/CodeGen/CGCXXABI.h
index b736d94..1e4da63 100644
--- a/lib/CodeGen/CGCXXABI.h
+++ b/lib/CodeGen/CGCXXABI.h
@@ -353,6 +353,25 @@
/// \param addr - a pointer to pass to the destructor function.
virtual void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
llvm::Constant *dtor, llvm::Constant *addr);
+
+ /*************************** thread_local initialization ********************/
+
+ /// Emits ABI-required functions necessary to initialize thread_local
+ /// variables in this translation unit.
+ ///
+ /// \param Decls The thread_local declarations in this translation unit.
+ /// \param InitFunc If this translation unit contains any non-constant
+ /// initialization or non-trivial destruction for thread_local
+ /// variables, a function to perform the initialization. Otherwise, 0.
+ virtual void EmitThreadLocalInitFuncs(
+ llvm::ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *> > Decls,
+ llvm::Function *InitFunc);
+
+ /// Emit a reference to a non-local thread_local variable (including
+ /// triggering the initialization of all thread_local variables in its
+ /// translation unit).
+ virtual LValue EmitThreadLocalDeclRefExpr(CodeGenFunction &CGF,
+ const DeclRefExpr *DRE);
};
// Create an instance of a C++ ABI class:
diff --git a/lib/CodeGen/CGDeclCXX.cpp b/lib/CodeGen/CGDeclCXX.cpp
index b18fe45..d406227 100644
--- a/lib/CodeGen/CGDeclCXX.cpp
+++ b/lib/CodeGen/CGDeclCXX.cpp
@@ -156,7 +156,8 @@
static llvm::Function *
CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
llvm::FunctionType *ty,
- const Twine &name);
+ const Twine &name,
+ bool TLS = false);
/// Create a stub function, suitable for being passed to atexit,
/// which passes the given address to the given destructor function.
@@ -225,11 +226,11 @@
static llvm::Function *
CreateGlobalInitOrDestructFunction(CodeGenModule &CGM,
llvm::FunctionType *FTy,
- const Twine &Name) {
+ const Twine &Name, bool TLS) {
llvm::Function *Fn =
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
Name, &CGM.getModule());
- if (!CGM.getLangOpts().AppleKext) {
+ if (!CGM.getLangOpts().AppleKext && !TLS) {
// Set the section if needed.
if (const char *Section =
CGM.getTarget().getStaticInitSectionSpecifier())
@@ -255,9 +256,6 @@
CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D,
llvm::GlobalVariable *Addr,
bool PerformInit) {
- if (D->getTLSKind())
- ErrorUnsupported(D->getInit(), "dynamic TLS initialization");
-
llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
// Create a variable initialization function.
@@ -267,12 +265,20 @@
CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D, Addr,
PerformInit);
- if (D->hasAttr<InitPriorityAttr>()) {
+ if (D->getTLSKind()) {
+ // FIXME: Should we support init_priority for thread_local?
+ // FIXME: Ideally, initialization of instantiated thread_local static data
+ // members of class templates should not trigger initialization of other
+ // entities in the TU.
+ // FIXME: We only need to register one __cxa_thread_atexit function for the
+ // entire TU.
+ CXXThreadLocalInits.push_back(Fn);
+ } else if (D->hasAttr<InitPriorityAttr>()) {
unsigned int order = D->getAttr<InitPriorityAttr>()->getPriority();
OrderGlobalInits Key(order, PrioritizedCXXGlobalInits.size());
PrioritizedCXXGlobalInits.push_back(std::make_pair(Key, Fn));
DelayedCXXInitPosition.erase(D);
- } else {
+ } else {
llvm::DenseMap<const Decl *, unsigned>::iterator I =
DelayedCXXInitPosition.find(D);
if (I == DelayedCXXInitPosition.end()) {
@@ -285,6 +291,27 @@
}
}
+void CodeGenModule::EmitCXXThreadLocalInitFunc() {
+ llvm::Function *InitFn = 0;
+ if (!CXXThreadLocalInits.empty()) {
+ // Generate a guarded initialization function.
+ llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, false);
+ InitFn = CreateGlobalInitOrDestructFunction(
+ *this, FTy, "__tls_init", /*TLS*/ true);
+ llvm::GlobalVariable *Guard = new llvm::GlobalVariable(
+ getModule(), Int8Ty, false, llvm::GlobalVariable::InternalLinkage,
+ llvm::ConstantInt::get(Int8Ty, 0), "__tls_guard");
+ Guard->setThreadLocal(true);
+ CodeGenFunction(*this).GenerateCXXGlobalInitFunc(
+ InitFn, CXXThreadLocalInits.data(), CXXThreadLocalInits.size(), Guard);
+ }
+
+ getCXXABI().EmitThreadLocalInitFuncs(CXXThreadLocals, InitFn);
+
+ CXXThreadLocalInits.clear();
+ CXXThreadLocals.clear();
+}
+
void
CodeGenModule::EmitCXXGlobalInitFunc() {
while (!CXXGlobalInits.empty() && !CXXGlobalInits.back())
@@ -385,7 +412,8 @@
void CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
llvm::Constant **Decls,
- unsigned NumDecls) {
+ unsigned NumDecls,
+ llvm::GlobalVariable *Guard) {
// Initialize debug info if needed.
maybeInitializeDebugInfo();
@@ -393,6 +421,22 @@
getTypes().arrangeNullaryFunction(),
FunctionArgList(), SourceLocation());
+ llvm::BasicBlock *ExitBlock = 0;
+ if (Guard) {
+ // If we have a guard variable, check whether we've already performed these
+ // initializations. This happens for TLS initialization functions.
+ llvm::Value *GuardVal = Builder.CreateLoad(Guard);
+ llvm::Value *Uninit = Builder.CreateIsNull(GuardVal, "guard.uninitialized");
+ // Mark as initialized before initializing anything else. If the
+ // initializers use previously-initialized thread_local vars, that's
+ // probably supposed to be OK, but the standard doesn't say.
+ Builder.CreateStore(llvm::ConstantInt::get(GuardVal->getType(), 1), Guard);
+ llvm::BasicBlock *InitBlock = createBasicBlock("init");
+ ExitBlock = createBasicBlock("exit");
+ Builder.CreateCondBr(Uninit, InitBlock, ExitBlock);
+ EmitBlock(InitBlock);
+ }
+
RunCleanupsScope Scope(*this);
// When building in Objective-C++ ARC mode, create an autorelease pool
@@ -407,7 +451,12 @@
EmitRuntimeCall(Decls[i]);
Scope.ForceCleanup();
-
+
+ if (ExitBlock) {
+ Builder.CreateBr(ExitBlock);
+ EmitBlock(ExitBlock);
+ }
+
FinishFunction();
}
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 1c06b7d..a0725b5 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1824,8 +1824,12 @@
if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
// Check if this is a global variable.
- if (VD->hasLinkage() || VD->isStaticDataMember())
+ if (VD->hasLinkage() || VD->isStaticDataMember()) {
+ // If it's thread_local, emit a call to its wrapper function instead.
+ if (VD->getTLSKind() == VarDecl::TLS_Dynamic)
+ return CGM.getCXXABI().EmitThreadLocalDeclRefExpr(*this, E);
return EmitGlobalVarDeclLValue(*this, E, VD);
+ }
bool isBlockVariable = VD->hasAttr<BlocksAttr>();
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index f4ac086..6e2d627 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -2628,7 +2628,8 @@
/// variables.
void GenerateCXXGlobalInitFunc(llvm::Function *Fn,
llvm::Constant **Decls,
- unsigned NumDecls);
+ unsigned NumDecls,
+ llvm::GlobalVariable *Guard = 0);
/// GenerateCXXGlobalDtorsFunc - Generates code for destroying global
/// variables.
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 42be779..fdd3568 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -176,6 +176,7 @@
EmitDeferred();
EmitCXXGlobalInitFunc();
EmitCXXGlobalDtorFunc();
+ EmitCXXThreadLocalInitFunc();
if (ObjCRuntime)
if (llvm::Function *ObjCInitFunction = ObjCRuntime->ModuleInitFunction())
AddGlobalCtor(ObjCInitFunction);
@@ -1477,8 +1478,10 @@
GV->setVisibility(GetLLVMVisibility(LV.getVisibility()));
}
- if (D->getTLSKind())
+ if (D->getTLSKind()) {
+ CXXThreadLocals.push_back(std::make_pair(D, GV));
setTLSMode(GV, *D);
+ }
}
if (AddrSpace != Ty->getAddressSpace())
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 1a803f3..0f4fe8a 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -317,6 +317,14 @@
llvm::GlobalValue *> StaticExternCMap;
StaticExternCMap StaticExternCValues;
+ /// \brief thread_local variables defined or used in this TU.
+ std::vector<std::pair<const VarDecl *, llvm::GlobalVariable *> >
+ CXXThreadLocals;
+
+ /// \brief thread_local variables with initializers that need to run
+ /// before any thread_local variable in this TU is odr-used.
+ std::vector<llvm::Constant*> CXXThreadLocalInits;
+
/// CXXGlobalInits - Global variables with initializers that need to run
/// before main.
std::vector<llvm::Constant*> CXXGlobalInits;
@@ -1026,6 +1034,9 @@
/// a C++ destructor Decl.
void EmitCXXDestructor(const CXXDestructorDecl *D, CXXDtorType Type);
+ /// \brief Emit the function that initializes C++ thread_local variables.
+ void EmitCXXThreadLocalInitFunc();
+
/// EmitCXXGlobalInitFunc - Emit the function that initializes C++ globals.
void EmitCXXGlobalInitFunc();
diff --git a/lib/CodeGen/ItaniumCXXABI.cpp b/lib/CodeGen/ItaniumCXXABI.cpp
index 382aa479..2714c9e 100644
--- a/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/lib/CodeGen/ItaniumCXXABI.cpp
@@ -146,6 +146,14 @@
llvm::GlobalVariable *DeclPtr, bool PerformInit);
void registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
llvm::Constant *dtor, llvm::Constant *addr);
+
+ llvm::Function *getOrCreateThreadLocalWrapper(const VarDecl *VD,
+ llvm::GlobalVariable *Var);
+ void EmitThreadLocalInitFuncs(
+ llvm::ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *> > Decls,
+ llvm::Function *InitFunc);
+ LValue EmitThreadLocalDeclRefExpr(CodeGenFunction &CGF,
+ const DeclRefExpr *DRE);
};
class ARMCXXABI : public ItaniumCXXABI {
@@ -1249,3 +1257,138 @@
CGF.registerGlobalDtorWithAtExit(dtor, addr);
}
+
+/// Get the appropriate linkage for the wrapper function. This is essentially
+/// the weak form of the variable's linkage; every translation unit which wneeds
+/// the wrapper emits a copy, and we want the linker to merge them.
+static llvm::GlobalValue::LinkageTypes getThreadLocalWrapperLinkage(
+ llvm::GlobalValue::LinkageTypes VarLinkage) {
+ if (llvm::GlobalValue::isLinkerPrivateLinkage(VarLinkage))
+ return llvm::GlobalValue::LinkerPrivateWeakLinkage;
+ // For internal linkage variables, we don't need an external or weak wrapper.
+ if (llvm::GlobalValue::isLocalLinkage(VarLinkage))
+ return VarLinkage;
+ return llvm::GlobalValue::WeakODRLinkage;
+}
+
+llvm::Function *
+ItaniumCXXABI::getOrCreateThreadLocalWrapper(const VarDecl *VD,
+ llvm::GlobalVariable *Var) {
+ // Mangle the name for the thread_local wrapper function.
+ SmallString<256> WrapperName;
+ {
+ llvm::raw_svector_ostream Out(WrapperName);
+ getMangleContext().mangleItaniumThreadLocalWrapper(VD, Out);
+ Out.flush();
+ }
+
+ if (llvm::Value *V = Var->getParent()->getNamedValue(WrapperName))
+ return cast<llvm::Function>(V);
+
+ llvm::Type *RetTy = Var->getType();
+ if (VD->getType()->isReferenceType())
+ RetTy = RetTy->getPointerElementType();
+
+ llvm::FunctionType *FnTy = llvm::FunctionType::get(RetTy, false);
+ llvm::Function *Wrapper = llvm::Function::Create(
+ FnTy, getThreadLocalWrapperLinkage(Var->getLinkage()), WrapperName.str(),
+ &CGM.getModule());
+ // Always resolve references to the wrapper at link time.
+ Wrapper->setVisibility(llvm::GlobalValue::HiddenVisibility);
+ return Wrapper;
+}
+
+void ItaniumCXXABI::EmitThreadLocalInitFuncs(
+ llvm::ArrayRef<std::pair<const VarDecl *, llvm::GlobalVariable *> > Decls,
+ llvm::Function *InitFunc) {
+ for (unsigned I = 0, N = Decls.size(); I != N; ++I) {
+ const VarDecl *VD = Decls[I].first;
+ llvm::GlobalVariable *Var = Decls[I].second;
+
+ // Mangle the name for the thread_local initialization function.
+ SmallString<256> InitFnName;
+ {
+ llvm::raw_svector_ostream Out(InitFnName);
+ getMangleContext().mangleItaniumThreadLocalInit(VD, Out);
+ Out.flush();
+ }
+
+ // If we have a definition for the variable, emit the initialization
+ // function as an alias to the global Init function (if any). Otherwise,
+ // produce a declaration of the initialization function.
+ llvm::GlobalValue *Init = 0;
+ bool InitIsInitFunc = false;
+ if (VD->hasDefinition()) {
+ InitIsInitFunc = true;
+ if (InitFunc)
+ Init =
+ new llvm::GlobalAlias(InitFunc->getType(), Var->getLinkage(),
+ InitFnName.str(), InitFunc, &CGM.getModule());
+ } else {
+ // Emit a weak global function referring to the initialization function.
+ // This function will not exist if the TU defining the thread_local
+ // variable in question does not need any dynamic initialization for
+ // its thread_local variables.
+ llvm::FunctionType *FnTy = llvm::FunctionType::get(CGM.VoidTy, false);
+ Init = llvm::Function::Create(
+ FnTy, llvm::GlobalVariable::ExternalWeakLinkage, InitFnName.str(),
+ &CGM.getModule());
+ }
+
+ if (Init)
+ Init->setVisibility(Var->getVisibility());
+
+ llvm::Function *Wrapper = getOrCreateThreadLocalWrapper(VD, Var);
+ llvm::LLVMContext &Context = CGM.getModule().getContext();
+ llvm::BasicBlock *Entry = llvm::BasicBlock::Create(Context, "", Wrapper);
+ CGBuilderTy Builder(Entry);
+ if (InitIsInitFunc) {
+ if (Init)
+ Builder.CreateCall(Init);
+ } else {
+ // Don't know whether we have an init function. Call it if it exists.
+ llvm::Value *Have = Builder.CreateIsNotNull(Init);
+ llvm::BasicBlock *InitBB = llvm::BasicBlock::Create(Context, "", Wrapper);
+ llvm::BasicBlock *ExitBB = llvm::BasicBlock::Create(Context, "", Wrapper);
+ Builder.CreateCondBr(Have, InitBB, ExitBB);
+
+ Builder.SetInsertPoint(InitBB);
+ Builder.CreateCall(Init);
+ Builder.CreateBr(ExitBB);
+
+ Builder.SetInsertPoint(ExitBB);
+ }
+
+ // For a reference, the result of the wrapper function is a pointer to
+ // the referenced object.
+ llvm::Value *Val = Var;
+ if (VD->getType()->isReferenceType()) {
+ llvm::LoadInst *LI = Builder.CreateLoad(Val);
+ LI->setAlignment(CGM.getContext().getDeclAlign(VD).getQuantity());
+ Val = LI;
+ }
+
+ Builder.CreateRet(Val);
+ }
+}
+
+LValue ItaniumCXXABI::EmitThreadLocalDeclRefExpr(CodeGenFunction &CGF,
+ const DeclRefExpr *DRE) {
+ const VarDecl *VD = cast<VarDecl>(DRE->getDecl());
+ QualType T = VD->getType();
+ llvm::Type *Ty = CGF.getTypes().ConvertTypeForMem(T);
+ llvm::Value *Val = CGF.CGM.GetAddrOfGlobalVar(VD, Ty);
+ llvm::Function *Wrapper =
+ getOrCreateThreadLocalWrapper(VD, cast<llvm::GlobalVariable>(Val));
+
+ Val = CGF.Builder.CreateCall(Wrapper);
+
+ LValue LV;
+ if (VD->getType()->isReferenceType())
+ LV = CGF.MakeNaturalAlignAddrLValue(Val, T);
+ else
+ LV = CGF.MakeAddrLValue(Val, DRE->getType(),
+ CGF.getContext().getDeclAlign(VD));
+ // FIXME: need setObjCGCLValueClass?
+ return LV;
+}