llvm-project/clang/lib/CodeGen/CGCXX.cpp

458 lines
18 KiB
C++

//===--- CGDecl.cpp - Emit LLVM Code for 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 C++ code generation.
//
//===----------------------------------------------------------------------===//
// We might split this into multiple files if it gets too unwieldy
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "Mangle.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/StmtCXX.h"
#include "llvm/ADT/StringExtras.h"
using namespace clang;
using namespace CodeGen;
llvm::Value *CodeGenFunction::LoadCXXThis() {
assert(isa<CXXMethodDecl>(CurFuncDecl) &&
"Must be in a C++ member function decl to load 'this'");
assert(cast<CXXMethodDecl>(CurFuncDecl)->isInstance() &&
"Must be in a C++ member function decl to load 'this'");
// FIXME: What if we're inside a block?
// ans: See how CodeGenFunction::LoadObjCSelf() uses
// CodeGenFunction::BlockForwardSelf() for how to do this.
return Builder.CreateLoad(LocalDeclMap[CXXThisDecl], "this");
}
void CodeGenModule::EmitCXXConstructors(const CXXConstructorDecl *D) {
EmitGlobal(GlobalDecl(D, Ctor_Complete));
EmitGlobal(GlobalDecl(D, Ctor_Base));
}
void CodeGenModule::EmitCXXConstructor(const CXXConstructorDecl *D,
CXXCtorType Type) {
llvm::Function *Fn = GetAddrOfCXXConstructor(D, Type);
CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
SetFunctionDefinitionAttributes(D, Fn);
SetLLVMFunctionAttributesForDefinition(D, Fn);
}
llvm::Function *
CodeGenModule::GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
CXXCtorType Type) {
const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
const llvm::FunctionType *FTy =
getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type),
FPT->isVariadic());
const char *Name = getMangledCXXCtorName(D, Type);
return cast<llvm::Function>(
GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(D, Type)));
}
const char *CodeGenModule::getMangledCXXCtorName(const CXXConstructorDecl *D,
CXXCtorType Type) {
llvm::SmallString<256> Name;
getMangleContext().mangleCXXCtor(D, Type, Name);
Name += '\0';
return UniqueMangledName(Name.begin(), Name.end());
}
void CodeGenModule::EmitCXXDestructors(const CXXDestructorDecl *D) {
if (D->isVirtual())
EmitGlobal(GlobalDecl(D, Dtor_Deleting));
EmitGlobal(GlobalDecl(D, Dtor_Complete));
EmitGlobal(GlobalDecl(D, Dtor_Base));
}
void CodeGenModule::EmitCXXDestructor(const CXXDestructorDecl *D,
CXXDtorType Type) {
llvm::Function *Fn = GetAddrOfCXXDestructor(D, Type);
CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
SetFunctionDefinitionAttributes(D, Fn);
SetLLVMFunctionAttributesForDefinition(D, Fn);
}
llvm::Function *
CodeGenModule::GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
CXXDtorType Type) {
const llvm::FunctionType *FTy =
getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type), false);
const char *Name = getMangledCXXDtorName(D, Type);
return cast<llvm::Function>(
GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(D, Type)));
}
const char *CodeGenModule::getMangledCXXDtorName(const CXXDestructorDecl *D,
CXXDtorType Type) {
llvm::SmallString<256> Name;
getMangleContext().mangleCXXDtor(D, Type, Name);
Name += '\0';
return UniqueMangledName(Name.begin(), Name.end());
}
llvm::Constant *
CodeGenFunction::GenerateThunk(llvm::Function *Fn, GlobalDecl GD,
bool Extern,
const ThunkAdjustment &ThisAdjustment) {
return GenerateCovariantThunk(Fn, GD, Extern,
CovariantThunkAdjustment(ThisAdjustment,
ThunkAdjustment()));
}
llvm::Value *
CodeGenFunction::DynamicTypeAdjust(llvm::Value *V,
const ThunkAdjustment &Adjustment) {
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
const llvm::Type *OrigTy = V->getType();
if (Adjustment.NonVirtual) {
// Do the non-virtual adjustment
V = Builder.CreateBitCast(V, Int8PtrTy);
V = Builder.CreateConstInBoundsGEP1_64(V, Adjustment.NonVirtual);
V = Builder.CreateBitCast(V, OrigTy);
}
if (!Adjustment.Virtual)
return V;
assert(Adjustment.Virtual % (LLVMPointerWidth / 8) == 0 &&
"vtable entry unaligned");
// Do the virtual this adjustment
const llvm::Type *PtrDiffTy = ConvertType(getContext().getPointerDiffType());
const llvm::Type *PtrDiffPtrTy = PtrDiffTy->getPointerTo();
llvm::Value *ThisVal = Builder.CreateBitCast(V, Int8PtrTy);
V = Builder.CreateBitCast(V, PtrDiffPtrTy->getPointerTo());
V = Builder.CreateLoad(V, "vtable");
llvm::Value *VTablePtr = V;
uint64_t VirtualAdjustment = Adjustment.Virtual / (LLVMPointerWidth / 8);
V = Builder.CreateConstInBoundsGEP1_64(VTablePtr, VirtualAdjustment);
V = Builder.CreateLoad(V);
V = Builder.CreateGEP(ThisVal, V);
return Builder.CreateBitCast(V, OrigTy);
}
llvm::Constant *
CodeGenFunction::GenerateCovariantThunk(llvm::Function *Fn,
GlobalDecl GD, bool Extern,
const CovariantThunkAdjustment &Adjustment) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
QualType ResultType = MD->getType()->getAs<FunctionType>()->getResultType();
FunctionArgList Args;
ImplicitParamDecl *ThisDecl =
ImplicitParamDecl::Create(getContext(), 0, SourceLocation(), 0,
MD->getThisType(getContext()));
Args.push_back(std::make_pair(ThisDecl, ThisDecl->getType()));
for (FunctionDecl::param_const_iterator i = MD->param_begin(),
e = MD->param_end();
i != e; ++i) {
ParmVarDecl *D = *i;
Args.push_back(std::make_pair(D, D->getType()));
}
IdentifierInfo *II
= &CGM.getContext().Idents.get("__thunk_named_foo_");
FunctionDecl *FD = FunctionDecl::Create(getContext(),
getContext().getTranslationUnitDecl(),
SourceLocation(), II, ResultType, 0,
Extern
? FunctionDecl::Extern
: FunctionDecl::Static,
false, true);
StartFunction(FD, ResultType, Fn, Args, SourceLocation());
// generate body
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
const llvm::Type *Ty =
CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD),
FPT->isVariadic());
llvm::Value *Callee = CGM.GetAddrOfFunction(GD, Ty);
CallArgList CallArgs;
bool ShouldAdjustReturnPointer = true;
QualType ArgType = MD->getThisType(getContext());
llvm::Value *Arg = Builder.CreateLoad(LocalDeclMap[ThisDecl], "this");
if (!Adjustment.ThisAdjustment.isEmpty()) {
// Do the this adjustment.
const llvm::Type *OrigTy = Callee->getType();
Arg = DynamicTypeAdjust(Arg, Adjustment.ThisAdjustment);
if (!Adjustment.ReturnAdjustment.isEmpty()) {
const CovariantThunkAdjustment &ReturnAdjustment =
CovariantThunkAdjustment(ThunkAdjustment(),
Adjustment.ReturnAdjustment);
Callee = CGM.BuildCovariantThunk(GD, Extern, ReturnAdjustment);
Callee = Builder.CreateBitCast(Callee, OrigTy);
ShouldAdjustReturnPointer = false;
}
}
CallArgs.push_back(std::make_pair(RValue::get(Arg), ArgType));
for (FunctionDecl::param_const_iterator i = MD->param_begin(),
e = MD->param_end();
i != e; ++i) {
ParmVarDecl *D = *i;
QualType ArgType = D->getType();
// llvm::Value *Arg = CGF.GetAddrOfLocalVar(Dst);
Expr *Arg = new (getContext()) DeclRefExpr(D, ArgType.getNonReferenceType(),
SourceLocation());
CallArgs.push_back(std::make_pair(EmitCallArg(Arg, ArgType), ArgType));
}
RValue RV = EmitCall(CGM.getTypes().getFunctionInfo(ResultType, CallArgs),
Callee, ReturnValueSlot(), CallArgs, MD);
if (ShouldAdjustReturnPointer && !Adjustment.ReturnAdjustment.isEmpty()) {
bool CanBeZero = !(ResultType->isReferenceType()
// FIXME: attr nonnull can't be zero either
/* || ResultType->hasAttr<NonNullAttr>() */ );
// Do the return result adjustment.
if (CanBeZero) {
llvm::BasicBlock *NonZeroBlock = createBasicBlock();
llvm::BasicBlock *ZeroBlock = createBasicBlock();
llvm::BasicBlock *ContBlock = createBasicBlock();
const llvm::Type *Ty = RV.getScalarVal()->getType();
llvm::Value *Zero = llvm::Constant::getNullValue(Ty);
Builder.CreateCondBr(Builder.CreateICmpNE(RV.getScalarVal(), Zero),
NonZeroBlock, ZeroBlock);
EmitBlock(NonZeroBlock);
llvm::Value *NZ =
DynamicTypeAdjust(RV.getScalarVal(), Adjustment.ReturnAdjustment);
EmitBranch(ContBlock);
EmitBlock(ZeroBlock);
llvm::Value *Z = RV.getScalarVal();
EmitBlock(ContBlock);
llvm::PHINode *RVOrZero = Builder.CreatePHI(Ty);
RVOrZero->reserveOperandSpace(2);
RVOrZero->addIncoming(NZ, NonZeroBlock);
RVOrZero->addIncoming(Z, ZeroBlock);
RV = RValue::get(RVOrZero);
} else
RV = RValue::get(DynamicTypeAdjust(RV.getScalarVal(),
Adjustment.ReturnAdjustment));
}
if (!ResultType->isVoidType())
EmitReturnOfRValue(RV, ResultType);
FinishFunction();
return Fn;
}
llvm::Constant *
CodeGenModule::GetAddrOfThunk(GlobalDecl GD,
const ThunkAdjustment &ThisAdjustment) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
// Compute mangled name
llvm::SmallString<256> OutName;
if (const CXXDestructorDecl* DD = dyn_cast<CXXDestructorDecl>(MD))
getMangleContext().mangleCXXDtorThunk(DD, GD.getDtorType(), ThisAdjustment,
OutName);
else
getMangleContext().mangleThunk(MD, ThisAdjustment, OutName);
OutName += '\0';
const char* Name = UniqueMangledName(OutName.begin(), OutName.end());
// Get function for mangled name
const llvm::Type *Ty = getTypes().GetFunctionTypeForVtable(MD);
return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl());
}
llvm::Constant *
CodeGenModule::GetAddrOfCovariantThunk(GlobalDecl GD,
const CovariantThunkAdjustment &Adjustment) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
// Compute mangled name
llvm::SmallString<256> OutName;
getMangleContext().mangleCovariantThunk(MD, Adjustment, OutName);
OutName += '\0';
const char* Name = UniqueMangledName(OutName.begin(), OutName.end());
// Get function for mangled name
const llvm::Type *Ty = getTypes().GetFunctionTypeForVtable(MD);
return GetOrCreateLLVMFunction(Name, Ty, GlobalDecl());
}
void CodeGenModule::BuildThunksForVirtual(GlobalDecl GD) {
CGVtableInfo::AdjustmentVectorTy *AdjPtr = getVtableInfo().getAdjustments(GD);
if (!AdjPtr)
return;
CGVtableInfo::AdjustmentVectorTy &Adj = *AdjPtr;
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
for (unsigned i = 0; i < Adj.size(); i++) {
GlobalDecl OGD = Adj[i].first;
const CXXMethodDecl *OMD = cast<CXXMethodDecl>(OGD.getDecl());
QualType nc_oret = OMD->getType()->getAs<FunctionType>()->getResultType();
CanQualType oret = getContext().getCanonicalType(nc_oret);
QualType nc_ret = MD->getType()->getAs<FunctionType>()->getResultType();
CanQualType ret = getContext().getCanonicalType(nc_ret);
ThunkAdjustment ReturnAdjustment;
if (oret != ret) {
QualType qD = nc_ret->getPointeeType();
QualType qB = nc_oret->getPointeeType();
CXXRecordDecl *D = cast<CXXRecordDecl>(qD->getAs<RecordType>()->getDecl());
CXXRecordDecl *B = cast<CXXRecordDecl>(qB->getAs<RecordType>()->getDecl());
ReturnAdjustment = ComputeThunkAdjustment(D, B);
}
ThunkAdjustment ThisAdjustment = Adj[i].second;
bool Extern = !cast<CXXRecordDecl>(OMD->getDeclContext())->isInAnonymousNamespace();
if (!ReturnAdjustment.isEmpty() || !ThisAdjustment.isEmpty()) {
CovariantThunkAdjustment CoAdj(ThisAdjustment, ReturnAdjustment);
llvm::Constant *FnConst;
if (!ReturnAdjustment.isEmpty())
FnConst = GetAddrOfCovariantThunk(GD, CoAdj);
else
FnConst = GetAddrOfThunk(GD, ThisAdjustment);
if (!isa<llvm::Function>(FnConst)) {
llvm::Constant *SubExpr =
cast<llvm::ConstantExpr>(FnConst)->getOperand(0);
llvm::Function *OldFn = cast<llvm::Function>(SubExpr);
std::string Name = OldFn->getNameStr();
GlobalDeclMap.erase(UniqueMangledName(Name.data(),
Name.data() + Name.size() + 1));
llvm::Constant *NewFnConst;
if (!ReturnAdjustment.isEmpty())
NewFnConst = GetAddrOfCovariantThunk(GD, CoAdj);
else
NewFnConst = GetAddrOfThunk(GD, ThisAdjustment);
llvm::Function *NewFn = cast<llvm::Function>(NewFnConst);
NewFn->takeName(OldFn);
llvm::Constant *NewPtrForOldDecl =
llvm::ConstantExpr::getBitCast(NewFn, OldFn->getType());
OldFn->replaceAllUsesWith(NewPtrForOldDecl);
OldFn->eraseFromParent();
FnConst = NewFn;
}
llvm::Function *Fn = cast<llvm::Function>(FnConst);
if (Fn->isDeclaration()) {
llvm::GlobalVariable::LinkageTypes linktype;
linktype = llvm::GlobalValue::WeakAnyLinkage;
if (!Extern)
linktype = llvm::GlobalValue::InternalLinkage;
Fn->setLinkage(linktype);
if (!Features.Exceptions && !Features.ObjCNonFragileABI)
Fn->addFnAttr(llvm::Attribute::NoUnwind);
Fn->setAlignment(2);
CodeGenFunction(*this).GenerateCovariantThunk(Fn, GD, Extern, CoAdj);
}
}
}
}
llvm::Constant *
CodeGenModule::BuildThunk(GlobalDecl GD, bool Extern,
const ThunkAdjustment &ThisAdjustment) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
llvm::SmallString<256> OutName;
if (const CXXDestructorDecl *D = dyn_cast<CXXDestructorDecl>(MD)) {
getMangleContext().mangleCXXDtorThunk(D, GD.getDtorType(), ThisAdjustment,
OutName);
} else
getMangleContext().mangleThunk(MD, ThisAdjustment, OutName);
llvm::GlobalVariable::LinkageTypes linktype;
linktype = llvm::GlobalValue::WeakAnyLinkage;
if (!Extern)
linktype = llvm::GlobalValue::InternalLinkage;
llvm::Type *Ptr8Ty=llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),0);
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
const llvm::FunctionType *FTy =
getTypes().GetFunctionType(getTypes().getFunctionInfo(MD),
FPT->isVariadic());
llvm::Function *Fn = llvm::Function::Create(FTy, linktype, OutName.str(),
&getModule());
CodeGenFunction(*this).GenerateThunk(Fn, GD, Extern, ThisAdjustment);
llvm::Constant *m = llvm::ConstantExpr::getBitCast(Fn, Ptr8Ty);
return m;
}
llvm::Constant *
CodeGenModule::BuildCovariantThunk(const GlobalDecl &GD, bool Extern,
const CovariantThunkAdjustment &Adjustment) {
const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
llvm::SmallString<256> OutName;
getMangleContext().mangleCovariantThunk(MD, Adjustment, OutName);
llvm::GlobalVariable::LinkageTypes linktype;
linktype = llvm::GlobalValue::WeakAnyLinkage;
if (!Extern)
linktype = llvm::GlobalValue::InternalLinkage;
llvm::Type *Ptr8Ty=llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext),0);
const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>();
const llvm::FunctionType *FTy =
getTypes().GetFunctionType(getTypes().getFunctionInfo(MD),
FPT->isVariadic());
llvm::Function *Fn = llvm::Function::Create(FTy, linktype, OutName.str(),
&getModule());
CodeGenFunction(*this).GenerateCovariantThunk(Fn, MD, Extern, Adjustment);
llvm::Constant *m = llvm::ConstantExpr::getBitCast(Fn, Ptr8Ty);
return m;
}
static llvm::Value *BuildVirtualCall(CodeGenFunction &CGF, uint64_t VtableIndex,
llvm::Value *This, const llvm::Type *Ty) {
Ty = Ty->getPointerTo()->getPointerTo()->getPointerTo();
llvm::Value *Vtable = CGF.Builder.CreateBitCast(This, Ty);
Vtable = CGF.Builder.CreateLoad(Vtable);
llvm::Value *VFuncPtr =
CGF.Builder.CreateConstInBoundsGEP1_64(Vtable, VtableIndex, "vfn");
return CGF.Builder.CreateLoad(VFuncPtr);
}
llvm::Value *
CodeGenFunction::BuildVirtualCall(const CXXMethodDecl *MD, llvm::Value *This,
const llvm::Type *Ty) {
MD = MD->getCanonicalDecl();
uint64_t VtableIndex = CGM.getVtableInfo().getMethodVtableIndex(MD);
return ::BuildVirtualCall(*this, VtableIndex, This, Ty);
}
llvm::Value *
CodeGenFunction::BuildVirtualCall(const CXXDestructorDecl *DD, CXXDtorType Type,
llvm::Value *&This, const llvm::Type *Ty) {
DD = cast<CXXDestructorDecl>(DD->getCanonicalDecl());
uint64_t VtableIndex =
CGM.getVtableInfo().getMethodVtableIndex(GlobalDecl(DD, Type));
return ::BuildVirtualCall(*this, VtableIndex, This, Ty);
}