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//===--- CGDeclCXX.cpp - Emit LLVM Code for C++ declarations --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code dealing with code generation of C++ declarations
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
using namespace clang;
using namespace CodeGen;
static void EmitDeclInit(CodeGenFunction &CGF, const VarDecl &D,
llvm::Constant *DeclPtr) {
assert(D.hasGlobalStorage() && "VarDecl must have global storage!");
assert(!D.getType()->isReferenceType() &&
"Should not call EmitDeclInit on a reference!");
CodeGenModule &CGM = CGF.CGM;
ASTContext &Context = CGF.getContext();
const Expr *Init = D.getInit();
QualType T = D.getType();
bool isVolatile = Context.getCanonicalType(T).isVolatileQualified();
if (!CGF.hasAggregateLLVMType(T)) {
llvm::Value *V = CGF.EmitScalarExpr(Init);
CGF.EmitStoreOfScalar(V, DeclPtr, isVolatile, T);
} else if (T->isAnyComplexType()) {
CGF.EmitComplexExprIntoAddr(Init, DeclPtr, isVolatile);
} else {
CGF.EmitAggExpr(Init, DeclPtr, isVolatile);
// Avoid generating destructor(s) for initialized objects.
if (!isa<CXXConstructExpr>(Init))
return;
const ConstantArrayType *Array = Context.getAsConstantArrayType(T);
if (Array)
T = Context.getBaseElementType(Array);
const RecordType *RT = T->getAs<RecordType>();
if (!RT)
return;
CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
if (RD->hasTrivialDestructor())
return;
CXXDestructorDecl *Dtor = RD->getDestructor(Context);
llvm::Constant *DtorFn;
if (Array) {
DtorFn =
CodeGenFunction(CGM).GenerateCXXAggrDestructorHelper(Dtor,
Array,
DeclPtr);
const llvm::Type *Int8PtrTy =
llvm::Type::getInt8PtrTy(CGM.getLLVMContext());
DeclPtr = llvm::Constant::getNullValue(Int8PtrTy);
} else
DtorFn = CGM.GetAddrOfCXXDestructor(Dtor, Dtor_Complete);
CGF.EmitCXXGlobalDtorRegistration(DtorFn, DeclPtr);
}
}
void CodeGenFunction::EmitCXXGlobalVarDeclInit(const VarDecl &D,
llvm::Constant *DeclPtr) {
const Expr *Init = D.getInit();
QualType T = D.getType();
if (!T->isReferenceType()) {
EmitDeclInit(*this, D, DeclPtr);
return;
}
ErrorUnsupported(Init, "global variable that binds to a reference");
}
void
CodeGenFunction::EmitCXXGlobalDtorRegistration(llvm::Constant *DtorFn,
llvm::Constant *DeclPtr) {
const llvm::Type *Int8PtrTy =
llvm::Type::getInt8Ty(VMContext)->getPointerTo();
std::vector<const llvm::Type *> Params;
Params.push_back(Int8PtrTy);
// Get the destructor function type
const llvm::Type *DtorFnTy =
llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext), Params, false);
DtorFnTy = llvm::PointerType::getUnqual(DtorFnTy);
Params.clear();
Params.push_back(DtorFnTy);
Params.push_back(Int8PtrTy);
Params.push_back(Int8PtrTy);
// Get the __cxa_atexit function type
// extern "C" int __cxa_atexit ( void (*f)(void *), void *p, void *d );
const llvm::FunctionType *AtExitFnTy =
llvm::FunctionType::get(ConvertType(getContext().IntTy), Params, false);
llvm::Constant *AtExitFn = CGM.CreateRuntimeFunction(AtExitFnTy,
"__cxa_atexit");
llvm::Constant *Handle = CGM.CreateRuntimeVariable(Int8PtrTy,
"__dso_handle");
llvm::Value *Args[3] = { llvm::ConstantExpr::getBitCast(DtorFn, DtorFnTy),
llvm::ConstantExpr::getBitCast(DeclPtr, Int8PtrTy),
llvm::ConstantExpr::getBitCast(Handle, Int8PtrTy) };
Builder.CreateCall(AtExitFn, &Args[0], llvm::array_endof(Args));
}
void
CodeGenModule::EmitCXXGlobalVarDeclInitFunc(const VarDecl *D) {
const llvm::FunctionType *FTy
= llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
false);
// Create a variable initialization function.
llvm::Function *Fn =
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
"__cxx_global_var_init", &TheModule);
CodeGenFunction(*this).GenerateCXXGlobalVarDeclInitFunc(Fn, D);
CXXGlobalInits.push_back(Fn);
}
void
CodeGenModule::EmitCXXGlobalInitFunc() {
if (CXXGlobalInits.empty())
return;
const llvm::FunctionType *FTy
= llvm::FunctionType::get(llvm::Type::getVoidTy(VMContext),
false);
// Create our global initialization function.
// FIXME: Should this be tweakable by targets?
llvm::Function *Fn =
llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage,
"__cxx_global_initialization", &TheModule);
CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn,
&CXXGlobalInits[0],
CXXGlobalInits.size());
AddGlobalCtor(Fn);
}
void CodeGenFunction::GenerateCXXGlobalVarDeclInitFunc(llvm::Function *Fn,
const VarDecl *D) {
StartFunction(GlobalDecl(), getContext().VoidTy, Fn, FunctionArgList(),
SourceLocation());
llvm::Constant *DeclPtr = CGM.GetAddrOfGlobalVar(D);
EmitCXXGlobalVarDeclInit(*D, DeclPtr);
FinishFunction();
}
void CodeGenFunction::GenerateCXXGlobalInitFunc(llvm::Function *Fn,
llvm::Constant **Decls,
unsigned NumDecls) {
StartFunction(GlobalDecl(), getContext().VoidTy, Fn, FunctionArgList(),
SourceLocation());
for (unsigned i = 0; i != NumDecls; ++i)
Builder.CreateCall(Decls[i]);
FinishFunction();
}
void
CodeGenFunction::EmitStaticCXXBlockVarDeclInit(const VarDecl &D,
llvm::GlobalVariable *GV) {
// FIXME: This should use __cxa_guard_{acquire,release}?
assert(!getContext().getLangOptions().ThreadsafeStatics &&
"thread safe statics are currently not supported!");
llvm::SmallString<256> GuardVName;
CGM.getMangleContext().mangleGuardVariable(&D, GuardVName);
// Create the guard variable.
llvm::GlobalValue *GuardV =
new llvm::GlobalVariable(CGM.getModule(), llvm::Type::getInt64Ty(VMContext),
false, GV->getLinkage(),
llvm::Constant::getNullValue(llvm::Type::getInt64Ty(VMContext)),
GuardVName.str());
// Load the first byte of the guard variable.
const llvm::Type *PtrTy
= llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext), 0);
llvm::Value *V = Builder.CreateLoad(Builder.CreateBitCast(GuardV, PtrTy),
"tmp");
// Compare it against 0.
llvm::Value *nullValue
= llvm::Constant::getNullValue(llvm::Type::getInt8Ty(VMContext));
llvm::Value *ICmp = Builder.CreateICmpEQ(V, nullValue , "tobool");
llvm::BasicBlock *InitBlock = createBasicBlock("init");
llvm::BasicBlock *EndBlock = createBasicBlock("init.end");
// If the guard variable is 0, jump to the initializer code.
Builder.CreateCondBr(ICmp, InitBlock, EndBlock);
EmitBlock(InitBlock);
if (D.getType()->isReferenceType()) {
QualType T = D.getType();
// We don't want to pass true for IsInitializer here, because a static
// reference to a temporary does not extend its lifetime.
RValue RV = EmitReferenceBindingToExpr(D.getInit(), T,
/*IsInitializer=*/false);
EmitStoreOfScalar(RV.getScalarVal(), GV, /*Volatile=*/false, T);
} else
EmitDeclInit(*this, D, GV);
Builder.CreateStore(llvm::ConstantInt::get(llvm::Type::getInt8Ty(VMContext),
1),
Builder.CreateBitCast(GuardV, PtrTy));
EmitBlock(EndBlock);
}
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