Emit the TLS intialization functions into a list.

Add the TLS initialization functions to a list of initialization functions. The
back-end takes this list and places the function pointers into the correct
section. This way they're called before `main().'

<rdar://problem/13733006>

llvm-svn: 180739
This commit is contained in:
Bill Wendling 2013-04-29 22:27:16 +00:00
parent 3e1758c045
commit 96a77693be
4 changed files with 59 additions and 0 deletions

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@ -304,6 +304,7 @@ void CodeGenModule::EmitCXXThreadLocalInitFunc() {
Guard->setThreadLocal(true); Guard->setThreadLocal(true);
CodeGenFunction(*this) CodeGenFunction(*this)
.GenerateCXXGlobalInitFunc(InitFn, CXXThreadLocalInits, Guard); .GenerateCXXGlobalInitFunc(InitFn, CXXThreadLocalInits, Guard);
AddTLSInitFunc(InitFn);
} }
getCXXABI().EmitThreadLocalInitFuncs(CXXThreadLocals, InitFn); getCXXABI().EmitThreadLocalInitFuncs(CXXThreadLocals, InitFn);

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@ -182,6 +182,7 @@ void CodeGenModule::Release() {
AddGlobalCtor(ObjCInitFunction); AddGlobalCtor(ObjCInitFunction);
EmitCtorList(GlobalCtors, "llvm.global_ctors"); EmitCtorList(GlobalCtors, "llvm.global_ctors");
EmitCtorList(GlobalDtors, "llvm.global_dtors"); EmitCtorList(GlobalDtors, "llvm.global_dtors");
EmitTLSList(TLSInitFuncs);
EmitGlobalAnnotations(); EmitGlobalAnnotations();
EmitStaticExternCAliases(); EmitStaticExternCAliases();
EmitLLVMUsed(); EmitLLVMUsed();
@ -479,6 +480,12 @@ void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) {
GlobalDtors.push_back(std::make_pair(Dtor, Priority)); GlobalDtors.push_back(std::make_pair(Dtor, Priority));
} }
/// AddTLSInitFunc - Add a function to the list that will initialize TLS
/// variables before main() runs.
void CodeGenModule::AddTLSInitFunc(llvm::Function *Init) {
TLSInitFuncs.push_back(Init);
}
void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) { void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) {
// Ctor function type is void()*. // Ctor function type is void()*.
llvm::FunctionType* CtorFTy = llvm::FunctionType::get(VoidTy, false); llvm::FunctionType* CtorFTy = llvm::FunctionType::get(VoidTy, false);
@ -507,6 +514,25 @@ void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) {
} }
} }
void CodeGenModule::EmitTLSList(ArrayRef<llvm::Constant*> Fns) {
if (Fns.empty()) return;
// TLS init function types are void()*.
llvm::FunctionType* TLSFTy = llvm::FunctionType::get(VoidTy, false);
llvm::Type *TLSPFTy = llvm::PointerType::getUnqual(TLSFTy);
SmallVector<llvm::Constant*, 8> Inits;
for (ArrayRef<llvm::Constant*>::iterator I = Fns.begin(),
E = Fns.end(); I != E; ++I)
Inits.push_back(llvm::ConstantExpr::getBitCast(*I, TLSPFTy));
llvm::ArrayType *AT = llvm::ArrayType::get(TLSPFTy, Inits.size());
new llvm::GlobalVariable(TheModule, AT, false,
llvm::GlobalValue::AppendingLinkage,
llvm::ConstantArray::get(AT, Inits),
"llvm.tls_init_funcs");
}
llvm::GlobalValue::LinkageTypes llvm::GlobalValue::LinkageTypes
CodeGenModule::getFunctionLinkage(const FunctionDecl *D) { CodeGenModule::getFunctionLinkage(const FunctionDecl *D) {
GVALinkage Linkage = getContext().GetGVALinkageForFunction(D); GVALinkage Linkage = getContext().GetGVALinkageForFunction(D);

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@ -293,6 +293,10 @@ class CodeGenModule : public CodeGenTypeCache {
/// priorities to be emitted when the translation unit is complete. /// priorities to be emitted when the translation unit is complete.
CtorList GlobalDtors; CtorList GlobalDtors;
/// TLSInitFuncs - Store the list of TLS initialization functions toe be
/// emitted with the translation unit is complete.
std::vector<llvm::Constant*> TLSInitFuncs;
/// MangledDeclNames - A map of canonical GlobalDecls to their mangled names. /// MangledDeclNames - A map of canonical GlobalDecls to their mangled names.
llvm::DenseMap<GlobalDecl, StringRef> MangledDeclNames; llvm::DenseMap<GlobalDecl, StringRef> MangledDeclNames;
llvm::BumpPtrAllocator MangledNamesAllocator; llvm::BumpPtrAllocator MangledNamesAllocator;
@ -1053,11 +1057,18 @@ private:
void AddGlobalCtor(llvm::Function *Ctor, int Priority=65535); void AddGlobalCtor(llvm::Function *Ctor, int Priority=65535);
void AddGlobalDtor(llvm::Function *Dtor, int Priority=65535); void AddGlobalDtor(llvm::Function *Dtor, int Priority=65535);
void AddTLSInitFunc(llvm::Function *Init);
/// EmitCtorList - Generates a global array of functions and priorities using /// EmitCtorList - Generates a global array of functions and priorities using
/// the given list and name. This array will have appending linkage and is /// the given list and name. This array will have appending linkage and is
/// suitable for use as a LLVM constructor or destructor array. /// suitable for use as a LLVM constructor or destructor array.
void EmitCtorList(const CtorList &Fns, const char *GlobalName); void EmitCtorList(const CtorList &Fns, const char *GlobalName);
/// EmitTLSList - Generates a global array of functions with the name
/// `llvm.tls_init_funcs'. This array will have appending linkage and is meant
/// to hold initialization functions for TLS variables.
void EmitTLSList(ArrayRef<llvm::Constant*> Fns);
/// EmitFundamentalRTTIDescriptor - Emit the RTTI descriptors for the /// EmitFundamentalRTTIDescriptor - Emit the RTTI descriptors for the
/// given type. /// given type.
void EmitFundamentalRTTIDescriptor(QualType Type); void EmitFundamentalRTTIDescriptor(QualType Type);

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@ -0,0 +1,21 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -std=c++11 -S -emit-llvm %s -o - | FileCheck -check-prefix=BITCODE %s
// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -std=c++11 -S %s -o - | FileCheck -check-prefix=ASM %s
// BITCODE: @llvm.tls_init_funcs = appending global [1 x void ()*] [void ()* @__tls_init]
struct A {
A();
};
struct B {
int i;
B(int i);
};
thread_local int i = 37;
thread_local A a;
thread_local B b(927);
// ASM: .section __DATA,__thread_init,thread_local_init_function_pointers
// ASM: .align 3
// ASM: .quad ___tls_init