//===--- 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; RValue CodeGenFunction::EmitCXXMemberCall(const CXXMethodDecl *MD, llvm::Value *Callee, ReturnValueSlot ReturnValue, llvm::Value *This, CallExpr::const_arg_iterator ArgBeg, CallExpr::const_arg_iterator ArgEnd) { assert(MD->isInstance() && "Trying to emit a member call expr on a static method!"); const FunctionProtoType *FPT = MD->getType()->getAs(); CallArgList Args; // Push the this ptr. Args.push_back(std::make_pair(RValue::get(This), MD->getThisType(getContext()))); // And the rest of the call args EmitCallArgs(Args, FPT, ArgBeg, ArgEnd); QualType ResultType = MD->getType()->getAs()->getResultType(); return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args), Callee, ReturnValue, Args, MD); } /// canDevirtualizeMemberFunctionCalls - Checks whether virtual calls on given /// expr can be devirtualized. static bool canDevirtualizeMemberFunctionCalls(const Expr *Base) { if (const DeclRefExpr *DRE = dyn_cast(Base)) { if (const VarDecl *VD = dyn_cast(DRE->getDecl())) { // This is a record decl. We know the type and can devirtualize it. return VD->getType()->isRecordType(); } return false; } // We can always devirtualize calls on temporary object expressions. if (isa(Base)) return true; // And calls on bound temporaries. if (isa(Base)) return true; // Check if this is a call expr that returns a record type. if (const CallExpr *CE = dyn_cast(Base)) return CE->getCallReturnType()->isRecordType(); // We can't devirtualize the call. return false; } RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE, ReturnValueSlot ReturnValue) { if (isa(CE->getCallee()->IgnoreParens())) return EmitCXXMemberPointerCallExpr(CE, ReturnValue); const MemberExpr *ME = cast(CE->getCallee()->IgnoreParens()); const CXXMethodDecl *MD = cast(ME->getMemberDecl()); if (MD->isStatic()) { // The method is static, emit it as we would a regular call. llvm::Value *Callee = CGM.GetAddrOfFunction(MD); return EmitCall(getContext().getPointerType(MD->getType()), Callee, ReturnValue, CE->arg_begin(), CE->arg_end()); } const FunctionProtoType *FPT = MD->getType()->getAs(); const llvm::Type *Ty = CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD), FPT->isVariadic()); llvm::Value *This; if (ME->isArrow()) This = EmitScalarExpr(ME->getBase()); else { LValue BaseLV = EmitLValue(ME->getBase()); This = BaseLV.getAddress(); } if (MD->isCopyAssignment() && MD->isTrivial()) { // We don't like to generate the trivial copy assignment operator when // it isn't necessary; just produce the proper effect here. llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress(); EmitAggregateCopy(This, RHS, CE->getType()); return RValue::get(This); } // C++ [class.virtual]p12: // Explicit qualification with the scope operator (5.1) suppresses the // virtual call mechanism. // // We also don't emit a virtual call if the base expression has a record type // because then we know what the type is. llvm::Value *Callee; if (const CXXDestructorDecl *Destructor = dyn_cast(MD)) { if (Destructor->isTrivial()) return RValue::get(0); if (MD->isVirtual() && !ME->hasQualifier() && !canDevirtualizeMemberFunctionCalls(ME->getBase())) { Callee = BuildVirtualCall(Destructor, Dtor_Complete, This, Ty); } else { Callee = CGM.GetAddrOfFunction(GlobalDecl(Destructor, Dtor_Complete), Ty); } } else if (MD->isVirtual() && !ME->hasQualifier() && !canDevirtualizeMemberFunctionCalls(ME->getBase())) { Callee = BuildVirtualCall(MD, This, Ty); } else { Callee = CGM.GetAddrOfFunction(MD, Ty); } return EmitCXXMemberCall(MD, Callee, ReturnValue, This, CE->arg_begin(), CE->arg_end()); } RValue CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E, ReturnValueSlot ReturnValue) { const BinaryOperator *BO = cast(E->getCallee()->IgnoreParens()); const Expr *BaseExpr = BO->getLHS(); const Expr *MemFnExpr = BO->getRHS(); const MemberPointerType *MPT = MemFnExpr->getType()->getAs(); const FunctionProtoType *FPT = MPT->getPointeeType()->getAs(); const CXXRecordDecl *RD = cast(MPT->getClass()->getAs()->getDecl()); const llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(RD, FPT), FPT->isVariadic()); const llvm::Type *Int8PtrTy = llvm::Type::getInt8Ty(VMContext)->getPointerTo(); // Get the member function pointer. llvm::Value *MemFnPtr = CreateTempAlloca(ConvertType(MemFnExpr->getType()), "mem.fn"); EmitAggExpr(MemFnExpr, MemFnPtr, /*VolatileDest=*/false); // Emit the 'this' pointer. llvm::Value *This; if (BO->getOpcode() == BinaryOperator::PtrMemI) This = EmitScalarExpr(BaseExpr); else This = EmitLValue(BaseExpr).getAddress(); // Adjust it. llvm::Value *Adj = Builder.CreateStructGEP(MemFnPtr, 1); Adj = Builder.CreateLoad(Adj, "mem.fn.adj"); llvm::Value *Ptr = Builder.CreateBitCast(This, Int8PtrTy, "ptr"); Ptr = Builder.CreateGEP(Ptr, Adj, "adj"); This = Builder.CreateBitCast(Ptr, This->getType(), "this"); llvm::Value *FnPtr = Builder.CreateStructGEP(MemFnPtr, 0, "mem.fn.ptr"); const llvm::Type *PtrDiffTy = ConvertType(getContext().getPointerDiffType()); llvm::Value *FnAsInt = Builder.CreateLoad(FnPtr, "fn"); // If the LSB in the function pointer is 1, the function pointer points to // a virtual function. llvm::Value *IsVirtual = Builder.CreateAnd(FnAsInt, llvm::ConstantInt::get(PtrDiffTy, 1), "and"); IsVirtual = Builder.CreateTrunc(IsVirtual, llvm::Type::getInt1Ty(VMContext)); llvm::BasicBlock *FnVirtual = createBasicBlock("fn.virtual"); llvm::BasicBlock *FnNonVirtual = createBasicBlock("fn.nonvirtual"); llvm::BasicBlock *FnEnd = createBasicBlock("fn.end"); Builder.CreateCondBr(IsVirtual, FnVirtual, FnNonVirtual); EmitBlock(FnVirtual); const llvm::Type *VTableTy = FTy->getPointerTo()->getPointerTo()->getPointerTo(); llvm::Value *VTable = Builder.CreateBitCast(This, VTableTy); VTable = Builder.CreateLoad(VTable); VTable = Builder.CreateGEP(VTable, FnAsInt, "fn"); // Since the function pointer is 1 plus the virtual table offset, we // subtract 1 by using a GEP. VTable = Builder.CreateConstGEP1_64(VTable, (uint64_t)-1); llvm::Value *VirtualFn = Builder.CreateLoad(VTable, "virtualfn"); EmitBranch(FnEnd); EmitBlock(FnNonVirtual); // If the function is not virtual, just load the pointer. llvm::Value *NonVirtualFn = Builder.CreateLoad(FnPtr, "fn"); NonVirtualFn = Builder.CreateIntToPtr(NonVirtualFn, FTy->getPointerTo()); EmitBlock(FnEnd); llvm::PHINode *Callee = Builder.CreatePHI(FTy->getPointerTo()); Callee->reserveOperandSpace(2); Callee->addIncoming(VirtualFn, FnVirtual); Callee->addIncoming(NonVirtualFn, FnNonVirtual); CallArgList Args; QualType ThisType = getContext().getPointerType(getContext().getTagDeclType(RD)); // Push the this ptr. Args.push_back(std::make_pair(RValue::get(This), ThisType)); // And the rest of the call args EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end()); QualType ResultType = BO->getType()->getAs()->getResultType(); return EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args), Callee, ReturnValue, Args); } RValue CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue) { assert(MD->isInstance() && "Trying to emit a member call expr on a static method!"); if (MD->isCopyAssignment()) { const CXXRecordDecl *ClassDecl = cast(MD->getDeclContext()); if (ClassDecl->hasTrivialCopyAssignment()) { assert(!ClassDecl->hasUserDeclaredCopyAssignment() && "EmitCXXOperatorMemberCallExpr - user declared copy assignment"); llvm::Value *This = EmitLValue(E->getArg(0)).getAddress(); llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress(); QualType Ty = E->getType(); EmitAggregateCopy(This, Src, Ty); return RValue::get(This); } } const FunctionProtoType *FPT = MD->getType()->getAs(); const llvm::Type *Ty = CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD), FPT->isVariadic()); llvm::Value *This = EmitLValue(E->getArg(0)).getAddress(); llvm::Value *Callee; if (MD->isVirtual() && !canDevirtualizeMemberFunctionCalls(E->getArg(0))) Callee = BuildVirtualCall(MD, This, Ty); else Callee = CGM.GetAddrOfFunction(MD, Ty); return EmitCXXMemberCall(MD, Callee, ReturnValue, This, E->arg_begin() + 1, E->arg_end()); } llvm::Value *CodeGenFunction::LoadCXXThis() { assert(isa(CurFuncDecl) && "Must be in a C++ member function decl to load 'this'"); assert(cast(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"); } /// EmitCXXAggrConstructorCall - This routine essentially creates a (nested) /// for-loop to call the default constructor on individual members of the /// array. /// 'D' is the default constructor for elements of the array, 'ArrayTy' is the /// array type and 'ArrayPtr' points to the beginning fo the array. /// It is assumed that all relevant checks have been made by the caller. void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *D, const ConstantArrayType *ArrayTy, llvm::Value *ArrayPtr, CallExpr::const_arg_iterator ArgBeg, CallExpr::const_arg_iterator ArgEnd) { const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); llvm::Value * NumElements = llvm::ConstantInt::get(SizeTy, getContext().getConstantArrayElementCount(ArrayTy)); EmitCXXAggrConstructorCall(D, NumElements, ArrayPtr, ArgBeg, ArgEnd); } void CodeGenFunction::EmitCXXAggrConstructorCall(const CXXConstructorDecl *D, llvm::Value *NumElements, llvm::Value *ArrayPtr, CallExpr::const_arg_iterator ArgBeg, CallExpr::const_arg_iterator ArgEnd) { const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); // Create a temporary for the loop index and initialize it with 0. llvm::Value *IndexPtr = CreateTempAlloca(SizeTy, "loop.index"); llvm::Value *Zero = llvm::Constant::getNullValue(SizeTy); Builder.CreateStore(Zero, IndexPtr); // Start the loop with a block that tests the condition. llvm::BasicBlock *CondBlock = createBasicBlock("for.cond"); llvm::BasicBlock *AfterFor = createBasicBlock("for.end"); EmitBlock(CondBlock); llvm::BasicBlock *ForBody = createBasicBlock("for.body"); // Generate: if (loop-index < number-of-elements fall to the loop body, // otherwise, go to the block after the for-loop. llvm::Value *Counter = Builder.CreateLoad(IndexPtr); llvm::Value *IsLess = Builder.CreateICmpULT(Counter, NumElements, "isless"); // If the condition is true, execute the body. Builder.CreateCondBr(IsLess, ForBody, AfterFor); EmitBlock(ForBody); llvm::BasicBlock *ContinueBlock = createBasicBlock("for.inc"); // Inside the loop body, emit the constructor call on the array element. Counter = Builder.CreateLoad(IndexPtr); llvm::Value *Address = Builder.CreateInBoundsGEP(ArrayPtr, Counter, "arrayidx"); // C++ [class.temporary]p4: // There are two contexts in which temporaries are destroyed at a different // point than the end of the full-expression. The first context is when a // default constructor is called to initialize an element of an array. // If the constructor has one or more default arguments, the destruction of // every temporary created in a default argument expression is sequenced // before the construction of the next array element, if any. // Keep track of the current number of live temporaries. unsigned OldNumLiveTemporaries = LiveTemporaries.size(); EmitCXXConstructorCall(D, Ctor_Complete, Address, ArgBeg, ArgEnd); // Pop temporaries. while (LiveTemporaries.size() > OldNumLiveTemporaries) PopCXXTemporary(); EmitBlock(ContinueBlock); // Emit the increment of the loop counter. llvm::Value *NextVal = llvm::ConstantInt::get(SizeTy, 1); Counter = Builder.CreateLoad(IndexPtr); NextVal = Builder.CreateAdd(Counter, NextVal, "inc"); Builder.CreateStore(NextVal, IndexPtr); // Finally, branch back up to the condition for the next iteration. EmitBranch(CondBlock); // Emit the fall-through block. EmitBlock(AfterFor, true); } /// EmitCXXAggrDestructorCall - calls the default destructor on array /// elements in reverse order of construction. void CodeGenFunction::EmitCXXAggrDestructorCall(const CXXDestructorDecl *D, const ArrayType *Array, llvm::Value *This) { const ConstantArrayType *CA = dyn_cast(Array); assert(CA && "Do we support VLA for destruction ?"); uint64_t ElementCount = getContext().getConstantArrayElementCount(CA); const llvm::Type *SizeLTy = ConvertType(getContext().getSizeType()); llvm::Value* ElementCountPtr = llvm::ConstantInt::get(SizeLTy, ElementCount); EmitCXXAggrDestructorCall(D, ElementCountPtr, This); } /// EmitCXXAggrDestructorCall - calls the default destructor on array /// elements in reverse order of construction. void CodeGenFunction::EmitCXXAggrDestructorCall(const CXXDestructorDecl *D, llvm::Value *UpperCount, llvm::Value *This) { const llvm::Type *SizeLTy = ConvertType(getContext().getSizeType()); llvm::Value *One = llvm::ConstantInt::get(SizeLTy, 1); // Create a temporary for the loop index and initialize it with count of // array elements. llvm::Value *IndexPtr = CreateTempAlloca(SizeLTy, "loop.index"); // Store the number of elements in the index pointer. Builder.CreateStore(UpperCount, IndexPtr); // Start the loop with a block that tests the condition. llvm::BasicBlock *CondBlock = createBasicBlock("for.cond"); llvm::BasicBlock *AfterFor = createBasicBlock("for.end"); EmitBlock(CondBlock); llvm::BasicBlock *ForBody = createBasicBlock("for.body"); // Generate: if (loop-index != 0 fall to the loop body, // otherwise, go to the block after the for-loop. llvm::Value* zeroConstant = llvm::Constant::getNullValue(SizeLTy); llvm::Value *Counter = Builder.CreateLoad(IndexPtr); llvm::Value *IsNE = Builder.CreateICmpNE(Counter, zeroConstant, "isne"); // If the condition is true, execute the body. Builder.CreateCondBr(IsNE, ForBody, AfterFor); EmitBlock(ForBody); llvm::BasicBlock *ContinueBlock = createBasicBlock("for.inc"); // Inside the loop body, emit the constructor call on the array element. Counter = Builder.CreateLoad(IndexPtr); Counter = Builder.CreateSub(Counter, One); llvm::Value *Address = Builder.CreateInBoundsGEP(This, Counter, "arrayidx"); EmitCXXDestructorCall(D, Dtor_Complete, Address); EmitBlock(ContinueBlock); // Emit the decrement of the loop counter. Counter = Builder.CreateLoad(IndexPtr); Counter = Builder.CreateSub(Counter, One, "dec"); Builder.CreateStore(Counter, IndexPtr); // Finally, branch back up to the condition for the next iteration. EmitBranch(CondBlock); // Emit the fall-through block. EmitBlock(AfterFor, true); } /// GenerateCXXAggrDestructorHelper - Generates a helper function which when /// invoked, calls the default destructor on array elements in reverse order of /// construction. llvm::Constant * CodeGenFunction::GenerateCXXAggrDestructorHelper(const CXXDestructorDecl *D, const ArrayType *Array, llvm::Value *This) { FunctionArgList Args; ImplicitParamDecl *Dst = ImplicitParamDecl::Create(getContext(), 0, SourceLocation(), 0, getContext().getPointerType(getContext().VoidTy)); Args.push_back(std::make_pair(Dst, Dst->getType())); llvm::SmallString<16> Name; llvm::raw_svector_ostream(Name) << "__tcf_" << (++UniqueAggrDestructorCount); QualType R = getContext().VoidTy; const CGFunctionInfo &FI = CGM.getTypes().getFunctionInfo(R, Args); const llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType(FI, false); llvm::Function *Fn = llvm::Function::Create(FTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule()); IdentifierInfo *II = &CGM.getContext().Idents.get(Name.str()); FunctionDecl *FD = FunctionDecl::Create(getContext(), getContext().getTranslationUnitDecl(), SourceLocation(), II, R, 0, FunctionDecl::Static, false, true); StartFunction(FD, R, Fn, Args, SourceLocation()); QualType BaseElementTy = getContext().getBaseElementType(Array); const llvm::Type *BasePtr = ConvertType(BaseElementTy); BasePtr = llvm::PointerType::getUnqual(BasePtr); llvm::Value *BaseAddrPtr = Builder.CreateBitCast(This, BasePtr); EmitCXXAggrDestructorCall(D, Array, BaseAddrPtr); FinishFunction(); llvm::Type *Ptr8Ty = llvm::PointerType::get(llvm::Type::getInt8Ty(VMContext), 0); llvm::Constant *m = llvm::ConstantExpr::getBitCast(Fn, Ptr8Ty); return m; } void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D, CXXCtorType Type, llvm::Value *This, CallExpr::const_arg_iterator ArgBeg, CallExpr::const_arg_iterator ArgEnd) { if (D->isCopyConstructor()) { const CXXRecordDecl *ClassDecl = cast(D->getDeclContext()); if (ClassDecl->hasTrivialCopyConstructor()) { assert(!ClassDecl->hasUserDeclaredCopyConstructor() && "EmitCXXConstructorCall - user declared copy constructor"); const Expr *E = (*ArgBeg); QualType Ty = E->getType(); llvm::Value *Src = EmitLValue(E).getAddress(); EmitAggregateCopy(This, Src, Ty); return; } } else if (D->isTrivial()) { // FIXME: Track down why we're trying to generate calls to the trivial // default constructor! return; } llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(D, Type); EmitCXXMemberCall(D, Callee, ReturnValueSlot(), This, ArgBeg, ArgEnd); } void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD, CXXDtorType Type, llvm::Value *This) { llvm::Value *Callee = CGM.GetAddrOfCXXDestructor(DD, Type); CallArgList Args; // Push the this ptr. Args.push_back(std::make_pair(RValue::get(This), DD->getThisType(getContext()))); // Add a VTT parameter if necessary. // FIXME: This should not be a dummy null parameter! if (Type == Dtor_Base && DD->getParent()->getNumVBases() != 0) { QualType T = getContext().getPointerType(getContext().VoidPtrTy); Args.push_back(std::make_pair(RValue::get(CGM.EmitNullConstant(T)), T)); } // FIXME: We should try to share this code with EmitCXXMemberCall. QualType ResultType = DD->getType()->getAs()->getResultType(); EmitCall(CGM.getTypes().getFunctionInfo(ResultType, Args), Callee, ReturnValueSlot(), Args, DD); } void CodeGenFunction::EmitCXXConstructExpr(llvm::Value *Dest, const CXXConstructExpr *E) { assert(Dest && "Must have a destination!"); const CXXConstructorDecl *CD = E->getConstructor(); const ConstantArrayType *Array = getContext().getAsConstantArrayType(E->getType()); // For a copy constructor, even if it is trivial, must fall thru so // its argument is code-gen'ed. if (!CD->isCopyConstructor()) { QualType InitType = E->getType(); if (Array) InitType = getContext().getBaseElementType(Array); const CXXRecordDecl *RD = cast(InitType->getAs()->getDecl()); if (RD->hasTrivialConstructor()) return; } // Code gen optimization to eliminate copy constructor and return // its first argument instead. if (getContext().getLangOptions().ElideConstructors && E->isElidable()) { const Expr *Arg = E->getArg(0); if (const ImplicitCastExpr *ICE = dyn_cast(Arg)) { assert((ICE->getCastKind() == CastExpr::CK_NoOp || ICE->getCastKind() == CastExpr::CK_ConstructorConversion || ICE->getCastKind() == CastExpr::CK_UserDefinedConversion) && "Unknown implicit cast kind in constructor elision"); Arg = ICE->getSubExpr(); } if (const CXXFunctionalCastExpr *FCE = dyn_cast(Arg)) Arg = FCE->getSubExpr(); if (const CXXBindTemporaryExpr *BindExpr = dyn_cast(Arg)) Arg = BindExpr->getSubExpr(); EmitAggExpr(Arg, Dest, false); return; } if (Array) { QualType BaseElementTy = getContext().getBaseElementType(Array); const llvm::Type *BasePtr = ConvertType(BaseElementTy); BasePtr = llvm::PointerType::getUnqual(BasePtr); llvm::Value *BaseAddrPtr = Builder.CreateBitCast(Dest, BasePtr); EmitCXXAggrConstructorCall(CD, Array, BaseAddrPtr, E->arg_begin(), E->arg_end()); } else // Call the constructor. EmitCXXConstructorCall(CD, Ctor_Complete, Dest, E->arg_begin(), E->arg_end()); } 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(); const llvm::FunctionType *FTy = getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type), FPT->isVariadic()); const char *Name = getMangledCXXCtorName(D, Type); return cast( 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( 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(GD.getDecl()); QualType ResultType = MD->getType()->getAs()->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(); 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() */ ); // 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(GD.getDecl()); // Compute mangled name llvm::SmallString<256> OutName; if (const CXXDestructorDecl* DD = dyn_cast(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(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(GD.getDecl()); for (unsigned i = 0; i < Adj.size(); i++) { GlobalDecl OGD = Adj[i].first; const CXXMethodDecl *OMD = cast(OGD.getDecl()); QualType nc_oret = OMD->getType()->getAs()->getResultType(); CanQualType oret = getContext().getCanonicalType(nc_oret); QualType nc_ret = MD->getType()->getAs()->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(qD->getAs()->getDecl()); CXXRecordDecl *B = cast(qB->getAs()->getDecl()); ReturnAdjustment = ComputeThunkAdjustment(D, B); } ThunkAdjustment ThisAdjustment = Adj[i].second; bool Extern = !cast(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(FnConst)) { llvm::Constant *SubExpr = cast(FnConst)->getOperand(0); llvm::Function *OldFn = cast(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(NewFnConst); NewFn->takeName(OldFn); llvm::Constant *NewPtrForOldDecl = llvm::ConstantExpr::getBitCast(NewFn, OldFn->getType()); OldFn->replaceAllUsesWith(NewPtrForOldDecl); OldFn->eraseFromParent(); FnConst = NewFn; } llvm::Function *Fn = cast(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(GD.getDecl()); llvm::SmallString<256> OutName; if (const CXXDestructorDecl *D = dyn_cast(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(); 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(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(); 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; } llvm::Value * CodeGenFunction::GetVirtualCXXBaseClassOffset(llvm::Value *This, const CXXRecordDecl *ClassDecl, const CXXRecordDecl *BaseClassDecl) { const llvm::Type *Int8PtrTy = llvm::Type::getInt8Ty(VMContext)->getPointerTo(); llvm::Value *VTablePtr = Builder.CreateBitCast(This, Int8PtrTy->getPointerTo()); VTablePtr = Builder.CreateLoad(VTablePtr, "vtable"); int64_t VBaseOffsetIndex = CGM.getVtableInfo().getVirtualBaseOffsetIndex(ClassDecl, BaseClassDecl); llvm::Value *VBaseOffsetPtr = Builder.CreateConstGEP1_64(VTablePtr, VBaseOffsetIndex, "vbase.offset.ptr"); const llvm::Type *PtrDiffTy = ConvertType(getContext().getPointerDiffType()); VBaseOffsetPtr = Builder.CreateBitCast(VBaseOffsetPtr, PtrDiffTy->getPointerTo()); llvm::Value *VBaseOffset = Builder.CreateLoad(VBaseOffsetPtr, "vbase.offset"); return VBaseOffset; } 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(DD->getCanonicalDecl()); uint64_t VtableIndex = CGM.getVtableInfo().getMethodVtableIndex(GlobalDecl(DD, Type)); return ::BuildVirtualCall(*this, VtableIndex, This, Ty); } void CodeGenFunction::InitializeVtablePtrs(const CXXRecordDecl *ClassDecl) { if (!ClassDecl->isDynamicClass()) return; llvm::Constant *Vtable = CGM.getVtableInfo().getVtable(ClassDecl); CodeGenModule::AddrSubMap_t& AddressPoints = *(*CGM.AddressPoints[ClassDecl])[ClassDecl]; llvm::Value *ThisPtr = LoadCXXThis(); const ASTRecordLayout &Layout = getContext().getASTRecordLayout(ClassDecl); // Store address points for virtual bases for (CXXRecordDecl::base_class_const_iterator I = ClassDecl->vbases_begin(), E = ClassDecl->vbases_end(); I != E; ++I) { const CXXBaseSpecifier &Base = *I; CXXRecordDecl *BaseClassDecl = cast(Base.getType()->getAs()->getDecl()); uint64_t Offset = Layout.getVBaseClassOffset(BaseClassDecl); InitializeVtablePtrsRecursive(BaseClassDecl, Vtable, AddressPoints, ThisPtr, Offset); } // Store address points for non-virtual bases and current class InitializeVtablePtrsRecursive(ClassDecl, Vtable, AddressPoints, ThisPtr, 0); } void CodeGenFunction::InitializeVtablePtrsRecursive( const CXXRecordDecl *ClassDecl, llvm::Constant *Vtable, CodeGenModule::AddrSubMap_t& AddressPoints, llvm::Value *ThisPtr, uint64_t Offset) { if (!ClassDecl->isDynamicClass()) return; // Store address points for non-virtual bases const ASTRecordLayout &Layout = getContext().getASTRecordLayout(ClassDecl); for (CXXRecordDecl::base_class_const_iterator I = ClassDecl->bases_begin(), E = ClassDecl->bases_end(); I != E; ++I) { const CXXBaseSpecifier &Base = *I; if (Base.isVirtual()) continue; CXXRecordDecl *BaseClassDecl = cast(Base.getType()->getAs()->getDecl()); uint64_t NewOffset = Offset + Layout.getBaseClassOffset(BaseClassDecl); InitializeVtablePtrsRecursive(BaseClassDecl, Vtable, AddressPoints, ThisPtr, NewOffset); } // Compute the address point assert(AddressPoints.count(std::make_pair(ClassDecl, Offset)) && "Missing address point for class"); uint64_t AddressPoint = AddressPoints[std::make_pair(ClassDecl, Offset)]; llvm::Value *VtableAddressPoint = Builder.CreateConstInBoundsGEP2_64(Vtable, 0, AddressPoint); // Compute the address to store the address point const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGM.getLLVMContext()); llvm::Value *VtableField = Builder.CreateBitCast(ThisPtr, Int8PtrTy); VtableField = Builder.CreateConstInBoundsGEP1_64(VtableField, Offset/8); const llvm::Type *AddressPointPtrTy = VtableAddressPoint->getType()->getPointerTo(); VtableField = Builder.CreateBitCast(VtableField, AddressPointPtrTy); // Store address point Builder.CreateStore(VtableAddressPoint, VtableField); }