//===--- CGCall.cpp - Encapsulate calling convention details ----*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // These classes wrap the information about a call or function // definition used to handle ABI compliancy. // //===----------------------------------------------------------------------===// #include "CGCall.h" #include "ABIInfo.h" #include "CGCXXABI.h" #include "CodeGenFunction.h" #include "CodeGenModule.h" #include "TargetInfo.h" #include "clang/AST/Decl.h" #include "clang/AST/DeclCXX.h" #include "clang/AST/DeclObjC.h" #include "clang/Basic/TargetInfo.h" #include "clang/Frontend/CodeGenOptions.h" #include "llvm/ADT/StringExtras.h" #include "llvm/IR/Attributes.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/InlineAsm.h" #include "llvm/MC/SubtargetFeature.h" #include "llvm/Support/CallSite.h" #include "llvm/Transforms/Utils/Local.h" using namespace clang; using namespace CodeGen; /***/ static unsigned ClangCallConvToLLVMCallConv(CallingConv CC) { switch (CC) { default: return llvm::CallingConv::C; case CC_X86StdCall: return llvm::CallingConv::X86_StdCall; case CC_X86FastCall: return llvm::CallingConv::X86_FastCall; case CC_X86ThisCall: return llvm::CallingConv::X86_ThisCall; case CC_AAPCS: return llvm::CallingConv::ARM_AAPCS; case CC_AAPCS_VFP: return llvm::CallingConv::ARM_AAPCS_VFP; case CC_IntelOclBicc: return llvm::CallingConv::Intel_OCL_BI; // TODO: add support for CC_X86Pascal to llvm } } /// Derives the 'this' type for codegen purposes, i.e. ignoring method /// qualification. /// FIXME: address space qualification? static CanQualType GetThisType(ASTContext &Context, const CXXRecordDecl *RD) { QualType RecTy = Context.getTagDeclType(RD)->getCanonicalTypeInternal(); return Context.getPointerType(CanQualType::CreateUnsafe(RecTy)); } /// Returns the canonical formal type of the given C++ method. static CanQual GetFormalType(const CXXMethodDecl *MD) { return MD->getType()->getCanonicalTypeUnqualified() .getAs(); } /// Returns the "extra-canonicalized" return type, which discards /// qualifiers on the return type. Codegen doesn't care about them, /// and it makes ABI code a little easier to be able to assume that /// all parameter and return types are top-level unqualified. static CanQualType GetReturnType(QualType RetTy) { return RetTy->getCanonicalTypeUnqualified().getUnqualifiedType(); } /// Arrange the argument and result information for a value of the given /// unprototyped freestanding function type. const CGFunctionInfo & CodeGenTypes::arrangeFreeFunctionType(CanQual FTNP) { // When translating an unprototyped function type, always use a // variadic type. return arrangeLLVMFunctionInfo(FTNP->getResultType().getUnqualifiedType(), None, FTNP->getExtInfo(), RequiredArgs(0)); } /// Arrange the LLVM function layout for a value of the given function /// type, on top of any implicit parameters already stored. Use the /// given ExtInfo instead of the ExtInfo from the function type. static const CGFunctionInfo &arrangeLLVMFunctionInfo(CodeGenTypes &CGT, SmallVectorImpl &prefix, CanQual FTP, FunctionType::ExtInfo extInfo) { RequiredArgs required = RequiredArgs::forPrototypePlus(FTP, prefix.size()); // FIXME: Kill copy. for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i) prefix.push_back(FTP->getArgType(i)); CanQualType resultType = FTP->getResultType().getUnqualifiedType(); return CGT.arrangeLLVMFunctionInfo(resultType, prefix, extInfo, required); } /// Arrange the argument and result information for a free function (i.e. /// not a C++ or ObjC instance method) of the given type. static const CGFunctionInfo &arrangeFreeFunctionType(CodeGenTypes &CGT, SmallVectorImpl &prefix, CanQual FTP) { return arrangeLLVMFunctionInfo(CGT, prefix, FTP, FTP->getExtInfo()); } /// Given the formal ext-info of a C++ instance method, adjust it /// according to the C++ ABI in effect. static void adjustCXXMethodInfo(CodeGenTypes &CGT, FunctionType::ExtInfo &extInfo, bool isVariadic) { if (extInfo.getCC() == CC_Default) { CallingConv CC = CGT.getContext().getDefaultCXXMethodCallConv(isVariadic); extInfo = extInfo.withCallingConv(CC); } } /// Arrange the argument and result information for a free function (i.e. /// not a C++ or ObjC instance method) of the given type. static const CGFunctionInfo &arrangeCXXMethodType(CodeGenTypes &CGT, SmallVectorImpl &prefix, CanQual FTP) { FunctionType::ExtInfo extInfo = FTP->getExtInfo(); adjustCXXMethodInfo(CGT, extInfo, FTP->isVariadic()); return arrangeLLVMFunctionInfo(CGT, prefix, FTP, extInfo); } /// Arrange the argument and result information for a value of the /// given freestanding function type. const CGFunctionInfo & CodeGenTypes::arrangeFreeFunctionType(CanQual FTP) { SmallVector argTypes; return ::arrangeFreeFunctionType(*this, argTypes, FTP); } static CallingConv getCallingConventionForDecl(const Decl *D) { // Set the appropriate calling convention for the Function. if (D->hasAttr()) return CC_X86StdCall; if (D->hasAttr()) return CC_X86FastCall; if (D->hasAttr()) return CC_X86ThisCall; if (D->hasAttr()) return CC_X86Pascal; if (PcsAttr *PCS = D->getAttr()) return (PCS->getPCS() == PcsAttr::AAPCS ? CC_AAPCS : CC_AAPCS_VFP); if (D->hasAttr()) return CC_PnaclCall; if (D->hasAttr()) return CC_IntelOclBicc; return CC_C; } /// Arrange the argument and result information for a call to an /// unknown C++ non-static member function of the given abstract type. /// The member function must be an ordinary function, i.e. not a /// constructor or destructor. const CGFunctionInfo & CodeGenTypes::arrangeCXXMethodType(const CXXRecordDecl *RD, const FunctionProtoType *FTP) { SmallVector argTypes; // Add the 'this' pointer. argTypes.push_back(GetThisType(Context, RD)); return ::arrangeCXXMethodType(*this, argTypes, FTP->getCanonicalTypeUnqualified().getAs()); } /// Arrange the argument and result information for a declaration or /// definition of the given C++ non-static member function. The /// member function must be an ordinary function, i.e. not a /// constructor or destructor. const CGFunctionInfo & CodeGenTypes::arrangeCXXMethodDeclaration(const CXXMethodDecl *MD) { assert(!isa(MD) && "wrong method for contructors!"); assert(!isa(MD) && "wrong method for destructors!"); CanQual prototype = GetFormalType(MD); if (MD->isInstance()) { // The abstract case is perfectly fine. return arrangeCXXMethodType(MD->getParent(), prototype.getTypePtr()); } return arrangeFreeFunctionType(prototype); } /// Arrange the argument and result information for a declaration /// or definition to the given constructor variant. const CGFunctionInfo & CodeGenTypes::arrangeCXXConstructorDeclaration(const CXXConstructorDecl *D, CXXCtorType ctorKind) { SmallVector argTypes; argTypes.push_back(GetThisType(Context, D->getParent())); CanQualType resultType = Context.VoidTy; TheCXXABI.BuildConstructorSignature(D, ctorKind, resultType, argTypes); CanQual FTP = GetFormalType(D); RequiredArgs required = RequiredArgs::forPrototypePlus(FTP, argTypes.size()); // Add the formal parameters. for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i) argTypes.push_back(FTP->getArgType(i)); FunctionType::ExtInfo extInfo = FTP->getExtInfo(); adjustCXXMethodInfo(*this, extInfo, FTP->isVariadic()); return arrangeLLVMFunctionInfo(resultType, argTypes, extInfo, required); } /// Arrange the argument and result information for a declaration, /// definition, or call to the given destructor variant. It so /// happens that all three cases produce the same information. const CGFunctionInfo & CodeGenTypes::arrangeCXXDestructor(const CXXDestructorDecl *D, CXXDtorType dtorKind) { SmallVector argTypes; argTypes.push_back(GetThisType(Context, D->getParent())); CanQualType resultType = Context.VoidTy; TheCXXABI.BuildDestructorSignature(D, dtorKind, resultType, argTypes); CanQual FTP = GetFormalType(D); assert(FTP->getNumArgs() == 0 && "dtor with formal parameters"); assert(FTP->isVariadic() == 0 && "dtor with formal parameters"); FunctionType::ExtInfo extInfo = FTP->getExtInfo(); adjustCXXMethodInfo(*this, extInfo, false); return arrangeLLVMFunctionInfo(resultType, argTypes, extInfo, RequiredArgs::All); } /// Arrange the argument and result information for the declaration or /// definition of the given function. const CGFunctionInfo & CodeGenTypes::arrangeFunctionDeclaration(const FunctionDecl *FD) { if (const CXXMethodDecl *MD = dyn_cast(FD)) if (MD->isInstance()) return arrangeCXXMethodDeclaration(MD); CanQualType FTy = FD->getType()->getCanonicalTypeUnqualified(); assert(isa(FTy)); // When declaring a function without a prototype, always use a // non-variadic type. if (isa(FTy)) { CanQual noProto = FTy.getAs(); return arrangeLLVMFunctionInfo(noProto->getResultType(), None, noProto->getExtInfo(), RequiredArgs::All); } assert(isa(FTy)); return arrangeFreeFunctionType(FTy.getAs()); } /// Arrange the argument and result information for the declaration or /// definition of an Objective-C method. const CGFunctionInfo & CodeGenTypes::arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD) { // It happens that this is the same as a call with no optional // arguments, except also using the formal 'self' type. return arrangeObjCMessageSendSignature(MD, MD->getSelfDecl()->getType()); } /// Arrange the argument and result information for the function type /// through which to perform a send to the given Objective-C method, /// using the given receiver type. The receiver type is not always /// the 'self' type of the method or even an Objective-C pointer type. /// This is *not* the right method for actually performing such a /// message send, due to the possibility of optional arguments. const CGFunctionInfo & CodeGenTypes::arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD, QualType receiverType) { SmallVector argTys; argTys.push_back(Context.getCanonicalParamType(receiverType)); argTys.push_back(Context.getCanonicalParamType(Context.getObjCSelType())); // FIXME: Kill copy? for (ObjCMethodDecl::param_const_iterator i = MD->param_begin(), e = MD->param_end(); i != e; ++i) { argTys.push_back(Context.getCanonicalParamType((*i)->getType())); } FunctionType::ExtInfo einfo; einfo = einfo.withCallingConv(getCallingConventionForDecl(MD)); if (getContext().getLangOpts().ObjCAutoRefCount && MD->hasAttr()) einfo = einfo.withProducesResult(true); RequiredArgs required = (MD->isVariadic() ? RequiredArgs(argTys.size()) : RequiredArgs::All); return arrangeLLVMFunctionInfo(GetReturnType(MD->getResultType()), argTys, einfo, required); } const CGFunctionInfo & CodeGenTypes::arrangeGlobalDeclaration(GlobalDecl GD) { // FIXME: Do we need to handle ObjCMethodDecl? const FunctionDecl *FD = cast(GD.getDecl()); if (const CXXConstructorDecl *CD = dyn_cast(FD)) return arrangeCXXConstructorDeclaration(CD, GD.getCtorType()); if (const CXXDestructorDecl *DD = dyn_cast(FD)) return arrangeCXXDestructor(DD, GD.getDtorType()); return arrangeFunctionDeclaration(FD); } /// Arrange a call as unto a free function, except possibly with an /// additional number of formal parameters considered required. static const CGFunctionInfo & arrangeFreeFunctionLikeCall(CodeGenTypes &CGT, const CallArgList &args, const FunctionType *fnType, unsigned numExtraRequiredArgs) { assert(args.size() >= numExtraRequiredArgs); // In most cases, there are no optional arguments. RequiredArgs required = RequiredArgs::All; // If we have a variadic prototype, the required arguments are the // extra prefix plus the arguments in the prototype. if (const FunctionProtoType *proto = dyn_cast(fnType)) { if (proto->isVariadic()) required = RequiredArgs(proto->getNumArgs() + numExtraRequiredArgs); // If we don't have a prototype at all, but we're supposed to // explicitly use the variadic convention for unprototyped calls, // treat all of the arguments as required but preserve the nominal // possibility of variadics. } else if (CGT.CGM.getTargetCodeGenInfo() .isNoProtoCallVariadic(args, cast(fnType))) { required = RequiredArgs(args.size()); } return CGT.arrangeFreeFunctionCall(fnType->getResultType(), args, fnType->getExtInfo(), required); } /// Figure out the rules for calling a function with the given formal /// type using the given arguments. The arguments are necessary /// because the function might be unprototyped, in which case it's /// target-dependent in crazy ways. const CGFunctionInfo & CodeGenTypes::arrangeFreeFunctionCall(const CallArgList &args, const FunctionType *fnType) { return arrangeFreeFunctionLikeCall(*this, args, fnType, 0); } /// A block function call is essentially a free-function call with an /// extra implicit argument. const CGFunctionInfo & CodeGenTypes::arrangeBlockFunctionCall(const CallArgList &args, const FunctionType *fnType) { return arrangeFreeFunctionLikeCall(*this, args, fnType, 1); } const CGFunctionInfo & CodeGenTypes::arrangeFreeFunctionCall(QualType resultType, const CallArgList &args, FunctionType::ExtInfo info, RequiredArgs required) { // FIXME: Kill copy. SmallVector argTypes; for (CallArgList::const_iterator i = args.begin(), e = args.end(); i != e; ++i) argTypes.push_back(Context.getCanonicalParamType(i->Ty)); return arrangeLLVMFunctionInfo(GetReturnType(resultType), argTypes, info, required); } /// Arrange a call to a C++ method, passing the given arguments. const CGFunctionInfo & CodeGenTypes::arrangeCXXMethodCall(const CallArgList &args, const FunctionProtoType *FPT, RequiredArgs required) { // FIXME: Kill copy. SmallVector argTypes; for (CallArgList::const_iterator i = args.begin(), e = args.end(); i != e; ++i) argTypes.push_back(Context.getCanonicalParamType(i->Ty)); FunctionType::ExtInfo info = FPT->getExtInfo(); adjustCXXMethodInfo(*this, info, FPT->isVariadic()); return arrangeLLVMFunctionInfo(GetReturnType(FPT->getResultType()), argTypes, info, required); } const CGFunctionInfo & CodeGenTypes::arrangeFunctionDeclaration(QualType resultType, const FunctionArgList &args, const FunctionType::ExtInfo &info, bool isVariadic) { // FIXME: Kill copy. SmallVector argTypes; for (FunctionArgList::const_iterator i = args.begin(), e = args.end(); i != e; ++i) argTypes.push_back(Context.getCanonicalParamType((*i)->getType())); RequiredArgs required = (isVariadic ? RequiredArgs(args.size()) : RequiredArgs::All); return arrangeLLVMFunctionInfo(GetReturnType(resultType), argTypes, info, required); } const CGFunctionInfo &CodeGenTypes::arrangeNullaryFunction() { return arrangeLLVMFunctionInfo(getContext().VoidTy, None, FunctionType::ExtInfo(), RequiredArgs::All); } /// Arrange the argument and result information for an abstract value /// of a given function type. This is the method which all of the /// above functions ultimately defer to. const CGFunctionInfo & CodeGenTypes::arrangeLLVMFunctionInfo(CanQualType resultType, ArrayRef argTypes, FunctionType::ExtInfo info, RequiredArgs required) { #ifndef NDEBUG for (ArrayRef::const_iterator I = argTypes.begin(), E = argTypes.end(); I != E; ++I) assert(I->isCanonicalAsParam()); #endif unsigned CC = ClangCallConvToLLVMCallConv(info.getCC()); // Lookup or create unique function info. llvm::FoldingSetNodeID ID; CGFunctionInfo::Profile(ID, info, required, resultType, argTypes); void *insertPos = 0; CGFunctionInfo *FI = FunctionInfos.FindNodeOrInsertPos(ID, insertPos); if (FI) return *FI; // Construct the function info. We co-allocate the ArgInfos. FI = CGFunctionInfo::create(CC, info, resultType, argTypes, required); FunctionInfos.InsertNode(FI, insertPos); bool inserted = FunctionsBeingProcessed.insert(FI); (void)inserted; assert(inserted && "Recursively being processed?"); // Compute ABI information. getABIInfo().computeInfo(*FI); // Loop over all of the computed argument and return value info. If any of // them are direct or extend without a specified coerce type, specify the // default now. ABIArgInfo &retInfo = FI->getReturnInfo(); if (retInfo.canHaveCoerceToType() && retInfo.getCoerceToType() == 0) retInfo.setCoerceToType(ConvertType(FI->getReturnType())); for (CGFunctionInfo::arg_iterator I = FI->arg_begin(), E = FI->arg_end(); I != E; ++I) if (I->info.canHaveCoerceToType() && I->info.getCoerceToType() == 0) I->info.setCoerceToType(ConvertType(I->type)); bool erased = FunctionsBeingProcessed.erase(FI); (void)erased; assert(erased && "Not in set?"); return *FI; } CGFunctionInfo *CGFunctionInfo::create(unsigned llvmCC, const FunctionType::ExtInfo &info, CanQualType resultType, ArrayRef argTypes, RequiredArgs required) { void *buffer = operator new(sizeof(CGFunctionInfo) + sizeof(ArgInfo) * (argTypes.size() + 1)); CGFunctionInfo *FI = new(buffer) CGFunctionInfo(); FI->CallingConvention = llvmCC; FI->EffectiveCallingConvention = llvmCC; FI->ASTCallingConvention = info.getCC(); FI->NoReturn = info.getNoReturn(); FI->ReturnsRetained = info.getProducesResult(); FI->Required = required; FI->HasRegParm = info.getHasRegParm(); FI->RegParm = info.getRegParm(); FI->NumArgs = argTypes.size(); FI->getArgsBuffer()[0].type = resultType; for (unsigned i = 0, e = argTypes.size(); i != e; ++i) FI->getArgsBuffer()[i + 1].type = argTypes[i]; return FI; } /***/ void CodeGenTypes::GetExpandedTypes(QualType type, SmallVectorImpl &expandedTypes) { if (const ConstantArrayType *AT = Context.getAsConstantArrayType(type)) { uint64_t NumElts = AT->getSize().getZExtValue(); for (uint64_t Elt = 0; Elt < NumElts; ++Elt) GetExpandedTypes(AT->getElementType(), expandedTypes); } else if (const RecordType *RT = type->getAs()) { const RecordDecl *RD = RT->getDecl(); assert(!RD->hasFlexibleArrayMember() && "Cannot expand structure with flexible array."); if (RD->isUnion()) { // Unions can be here only in degenerative cases - all the fields are same // after flattening. Thus we have to use the "largest" field. const FieldDecl *LargestFD = 0; CharUnits UnionSize = CharUnits::Zero(); for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { const FieldDecl *FD = *i; assert(!FD->isBitField() && "Cannot expand structure with bit-field members."); CharUnits FieldSize = getContext().getTypeSizeInChars(FD->getType()); if (UnionSize < FieldSize) { UnionSize = FieldSize; LargestFD = FD; } } if (LargestFD) GetExpandedTypes(LargestFD->getType(), expandedTypes); } else { for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { assert(!i->isBitField() && "Cannot expand structure with bit-field members."); GetExpandedTypes(i->getType(), expandedTypes); } } } else if (const ComplexType *CT = type->getAs()) { llvm::Type *EltTy = ConvertType(CT->getElementType()); expandedTypes.push_back(EltTy); expandedTypes.push_back(EltTy); } else expandedTypes.push_back(ConvertType(type)); } llvm::Function::arg_iterator CodeGenFunction::ExpandTypeFromArgs(QualType Ty, LValue LV, llvm::Function::arg_iterator AI) { assert(LV.isSimple() && "Unexpected non-simple lvalue during struct expansion."); if (const ConstantArrayType *AT = getContext().getAsConstantArrayType(Ty)) { unsigned NumElts = AT->getSize().getZExtValue(); QualType EltTy = AT->getElementType(); for (unsigned Elt = 0; Elt < NumElts; ++Elt) { llvm::Value *EltAddr = Builder.CreateConstGEP2_32(LV.getAddress(), 0, Elt); LValue LV = MakeAddrLValue(EltAddr, EltTy); AI = ExpandTypeFromArgs(EltTy, LV, AI); } } else if (const RecordType *RT = Ty->getAs()) { RecordDecl *RD = RT->getDecl(); if (RD->isUnion()) { // Unions can be here only in degenerative cases - all the fields are same // after flattening. Thus we have to use the "largest" field. const FieldDecl *LargestFD = 0; CharUnits UnionSize = CharUnits::Zero(); for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { const FieldDecl *FD = *i; assert(!FD->isBitField() && "Cannot expand structure with bit-field members."); CharUnits FieldSize = getContext().getTypeSizeInChars(FD->getType()); if (UnionSize < FieldSize) { UnionSize = FieldSize; LargestFD = FD; } } if (LargestFD) { // FIXME: What are the right qualifiers here? LValue SubLV = EmitLValueForField(LV, LargestFD); AI = ExpandTypeFromArgs(LargestFD->getType(), SubLV, AI); } } else { for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { FieldDecl *FD = *i; QualType FT = FD->getType(); // FIXME: What are the right qualifiers here? LValue SubLV = EmitLValueForField(LV, FD); AI = ExpandTypeFromArgs(FT, SubLV, AI); } } } else if (const ComplexType *CT = Ty->getAs()) { QualType EltTy = CT->getElementType(); llvm::Value *RealAddr = Builder.CreateStructGEP(LV.getAddress(), 0, "real"); EmitStoreThroughLValue(RValue::get(AI++), MakeAddrLValue(RealAddr, EltTy)); llvm::Value *ImagAddr = Builder.CreateStructGEP(LV.getAddress(), 1, "imag"); EmitStoreThroughLValue(RValue::get(AI++), MakeAddrLValue(ImagAddr, EltTy)); } else { EmitStoreThroughLValue(RValue::get(AI), LV); ++AI; } return AI; } /// EnterStructPointerForCoercedAccess - Given a struct pointer that we are /// accessing some number of bytes out of it, try to gep into the struct to get /// at its inner goodness. Dive as deep as possible without entering an element /// with an in-memory size smaller than DstSize. static llvm::Value * EnterStructPointerForCoercedAccess(llvm::Value *SrcPtr, llvm::StructType *SrcSTy, uint64_t DstSize, CodeGenFunction &CGF) { // We can't dive into a zero-element struct. if (SrcSTy->getNumElements() == 0) return SrcPtr; llvm::Type *FirstElt = SrcSTy->getElementType(0); // If the first elt is at least as large as what we're looking for, or if the // first element is the same size as the whole struct, we can enter it. uint64_t FirstEltSize = CGF.CGM.getDataLayout().getTypeAllocSize(FirstElt); if (FirstEltSize < DstSize && FirstEltSize < CGF.CGM.getDataLayout().getTypeAllocSize(SrcSTy)) return SrcPtr; // GEP into the first element. SrcPtr = CGF.Builder.CreateConstGEP2_32(SrcPtr, 0, 0, "coerce.dive"); // If the first element is a struct, recurse. llvm::Type *SrcTy = cast(SrcPtr->getType())->getElementType(); if (llvm::StructType *SrcSTy = dyn_cast(SrcTy)) return EnterStructPointerForCoercedAccess(SrcPtr, SrcSTy, DstSize, CGF); return SrcPtr; } /// CoerceIntOrPtrToIntOrPtr - Convert a value Val to the specific Ty where both /// are either integers or pointers. This does a truncation of the value if it /// is too large or a zero extension if it is too small. static llvm::Value *CoerceIntOrPtrToIntOrPtr(llvm::Value *Val, llvm::Type *Ty, CodeGenFunction &CGF) { if (Val->getType() == Ty) return Val; if (isa(Val->getType())) { // If this is Pointer->Pointer avoid conversion to and from int. if (isa(Ty)) return CGF.Builder.CreateBitCast(Val, Ty, "coerce.val"); // Convert the pointer to an integer so we can play with its width. Val = CGF.Builder.CreatePtrToInt(Val, CGF.IntPtrTy, "coerce.val.pi"); } llvm::Type *DestIntTy = Ty; if (isa(DestIntTy)) DestIntTy = CGF.IntPtrTy; if (Val->getType() != DestIntTy) Val = CGF.Builder.CreateIntCast(Val, DestIntTy, false, "coerce.val.ii"); if (isa(Ty)) Val = CGF.Builder.CreateIntToPtr(Val, Ty, "coerce.val.ip"); return Val; } /// CreateCoercedLoad - Create a load from \arg SrcPtr interpreted as /// a pointer to an object of type \arg Ty. /// /// This safely handles the case when the src type is smaller than the /// destination type; in this situation the values of bits which not /// present in the src are undefined. static llvm::Value *CreateCoercedLoad(llvm::Value *SrcPtr, llvm::Type *Ty, CodeGenFunction &CGF) { llvm::Type *SrcTy = cast(SrcPtr->getType())->getElementType(); // If SrcTy and Ty are the same, just do a load. if (SrcTy == Ty) return CGF.Builder.CreateLoad(SrcPtr); uint64_t DstSize = CGF.CGM.getDataLayout().getTypeAllocSize(Ty); if (llvm::StructType *SrcSTy = dyn_cast(SrcTy)) { SrcPtr = EnterStructPointerForCoercedAccess(SrcPtr, SrcSTy, DstSize, CGF); SrcTy = cast(SrcPtr->getType())->getElementType(); } uint64_t SrcSize = CGF.CGM.getDataLayout().getTypeAllocSize(SrcTy); // If the source and destination are integer or pointer types, just do an // extension or truncation to the desired type. if ((isa(Ty) || isa(Ty)) && (isa(SrcTy) || isa(SrcTy))) { llvm::LoadInst *Load = CGF.Builder.CreateLoad(SrcPtr); return CoerceIntOrPtrToIntOrPtr(Load, Ty, CGF); } // If load is legal, just bitcast the src pointer. if (SrcSize >= DstSize) { // Generally SrcSize is never greater than DstSize, since this means we are // losing bits. However, this can happen in cases where the structure has // additional padding, for example due to a user specified alignment. // // FIXME: Assert that we aren't truncating non-padding bits when have access // to that information. llvm::Value *Casted = CGF.Builder.CreateBitCast(SrcPtr, llvm::PointerType::getUnqual(Ty)); llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted); // FIXME: Use better alignment / avoid requiring aligned load. Load->setAlignment(1); return Load; } // Otherwise do coercion through memory. This is stupid, but // simple. llvm::Value *Tmp = CGF.CreateTempAlloca(Ty); llvm::Type *I8PtrTy = CGF.Builder.getInt8PtrTy(); llvm::Value *Casted = CGF.Builder.CreateBitCast(Tmp, I8PtrTy); llvm::Value *SrcCasted = CGF.Builder.CreateBitCast(SrcPtr, I8PtrTy); // FIXME: Use better alignment. CGF.Builder.CreateMemCpy(Casted, SrcCasted, llvm::ConstantInt::get(CGF.IntPtrTy, SrcSize), 1, false); return CGF.Builder.CreateLoad(Tmp); } // Function to store a first-class aggregate into memory. We prefer to // store the elements rather than the aggregate to be more friendly to // fast-isel. // FIXME: Do we need to recurse here? static void BuildAggStore(CodeGenFunction &CGF, llvm::Value *Val, llvm::Value *DestPtr, bool DestIsVolatile, bool LowAlignment) { // Prefer scalar stores to first-class aggregate stores. if (llvm::StructType *STy = dyn_cast(Val->getType())) { for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { llvm::Value *EltPtr = CGF.Builder.CreateConstGEP2_32(DestPtr, 0, i); llvm::Value *Elt = CGF.Builder.CreateExtractValue(Val, i); llvm::StoreInst *SI = CGF.Builder.CreateStore(Elt, EltPtr, DestIsVolatile); if (LowAlignment) SI->setAlignment(1); } } else { llvm::StoreInst *SI = CGF.Builder.CreateStore(Val, DestPtr, DestIsVolatile); if (LowAlignment) SI->setAlignment(1); } } /// CreateCoercedStore - Create a store to \arg DstPtr from \arg Src, /// where the source and destination may have different types. /// /// This safely handles the case when the src type is larger than the /// destination type; the upper bits of the src will be lost. static void CreateCoercedStore(llvm::Value *Src, llvm::Value *DstPtr, bool DstIsVolatile, CodeGenFunction &CGF) { llvm::Type *SrcTy = Src->getType(); llvm::Type *DstTy = cast(DstPtr->getType())->getElementType(); if (SrcTy == DstTy) { CGF.Builder.CreateStore(Src, DstPtr, DstIsVolatile); return; } uint64_t SrcSize = CGF.CGM.getDataLayout().getTypeAllocSize(SrcTy); if (llvm::StructType *DstSTy = dyn_cast(DstTy)) { DstPtr = EnterStructPointerForCoercedAccess(DstPtr, DstSTy, SrcSize, CGF); DstTy = cast(DstPtr->getType())->getElementType(); } // If the source and destination are integer or pointer types, just do an // extension or truncation to the desired type. if ((isa(SrcTy) || isa(SrcTy)) && (isa(DstTy) || isa(DstTy))) { Src = CoerceIntOrPtrToIntOrPtr(Src, DstTy, CGF); CGF.Builder.CreateStore(Src, DstPtr, DstIsVolatile); return; } uint64_t DstSize = CGF.CGM.getDataLayout().getTypeAllocSize(DstTy); // If store is legal, just bitcast the src pointer. if (SrcSize <= DstSize) { llvm::Value *Casted = CGF.Builder.CreateBitCast(DstPtr, llvm::PointerType::getUnqual(SrcTy)); // FIXME: Use better alignment / avoid requiring aligned store. BuildAggStore(CGF, Src, Casted, DstIsVolatile, true); } else { // Otherwise do coercion through memory. This is stupid, but // simple. // Generally SrcSize is never greater than DstSize, since this means we are // losing bits. However, this can happen in cases where the structure has // additional padding, for example due to a user specified alignment. // // FIXME: Assert that we aren't truncating non-padding bits when have access // to that information. llvm::Value *Tmp = CGF.CreateTempAlloca(SrcTy); CGF.Builder.CreateStore(Src, Tmp); llvm::Type *I8PtrTy = CGF.Builder.getInt8PtrTy(); llvm::Value *Casted = CGF.Builder.CreateBitCast(Tmp, I8PtrTy); llvm::Value *DstCasted = CGF.Builder.CreateBitCast(DstPtr, I8PtrTy); // FIXME: Use better alignment. CGF.Builder.CreateMemCpy(DstCasted, Casted, llvm::ConstantInt::get(CGF.IntPtrTy, DstSize), 1, false); } } /***/ bool CodeGenModule::ReturnTypeUsesSRet(const CGFunctionInfo &FI) { return FI.getReturnInfo().isIndirect(); } bool CodeGenModule::ReturnTypeUsesFPRet(QualType ResultType) { if (const BuiltinType *BT = ResultType->getAs()) { switch (BT->getKind()) { default: return false; case BuiltinType::Float: return getTarget().useObjCFPRetForRealType(TargetInfo::Float); case BuiltinType::Double: return getTarget().useObjCFPRetForRealType(TargetInfo::Double); case BuiltinType::LongDouble: return getTarget().useObjCFPRetForRealType(TargetInfo::LongDouble); } } return false; } bool CodeGenModule::ReturnTypeUsesFP2Ret(QualType ResultType) { if (const ComplexType *CT = ResultType->getAs()) { if (const BuiltinType *BT = CT->getElementType()->getAs()) { if (BT->getKind() == BuiltinType::LongDouble) return getTarget().useObjCFP2RetForComplexLongDouble(); } } return false; } llvm::FunctionType *CodeGenTypes::GetFunctionType(GlobalDecl GD) { const CGFunctionInfo &FI = arrangeGlobalDeclaration(GD); return GetFunctionType(FI); } llvm::FunctionType * CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI) { bool Inserted = FunctionsBeingProcessed.insert(&FI); (void)Inserted; assert(Inserted && "Recursively being processed?"); SmallVector argTypes; llvm::Type *resultType = 0; const ABIArgInfo &retAI = FI.getReturnInfo(); switch (retAI.getKind()) { case ABIArgInfo::Expand: llvm_unreachable("Invalid ABI kind for return argument"); case ABIArgInfo::Extend: case ABIArgInfo::Direct: resultType = retAI.getCoerceToType(); break; case ABIArgInfo::Indirect: { assert(!retAI.getIndirectAlign() && "Align unused on indirect return."); resultType = llvm::Type::getVoidTy(getLLVMContext()); QualType ret = FI.getReturnType(); llvm::Type *ty = ConvertType(ret); unsigned addressSpace = Context.getTargetAddressSpace(ret); argTypes.push_back(llvm::PointerType::get(ty, addressSpace)); break; } case ABIArgInfo::Ignore: resultType = llvm::Type::getVoidTy(getLLVMContext()); break; } // Add in all of the required arguments. CGFunctionInfo::const_arg_iterator it = FI.arg_begin(), ie; if (FI.isVariadic()) { ie = it + FI.getRequiredArgs().getNumRequiredArgs(); } else { ie = FI.arg_end(); } for (; it != ie; ++it) { const ABIArgInfo &argAI = it->info; // Insert a padding type to ensure proper alignment. if (llvm::Type *PaddingType = argAI.getPaddingType()) argTypes.push_back(PaddingType); switch (argAI.getKind()) { case ABIArgInfo::Ignore: break; case ABIArgInfo::Indirect: { // indirect arguments are always on the stack, which is addr space #0. llvm::Type *LTy = ConvertTypeForMem(it->type); argTypes.push_back(LTy->getPointerTo()); break; } case ABIArgInfo::Extend: case ABIArgInfo::Direct: { // If the coerce-to type is a first class aggregate, flatten it. Either // way is semantically identical, but fast-isel and the optimizer // generally likes scalar values better than FCAs. llvm::Type *argType = argAI.getCoerceToType(); if (llvm::StructType *st = dyn_cast(argType)) { for (unsigned i = 0, e = st->getNumElements(); i != e; ++i) argTypes.push_back(st->getElementType(i)); } else { argTypes.push_back(argType); } break; } case ABIArgInfo::Expand: GetExpandedTypes(it->type, argTypes); break; } } bool Erased = FunctionsBeingProcessed.erase(&FI); (void)Erased; assert(Erased && "Not in set?"); return llvm::FunctionType::get(resultType, argTypes, FI.isVariadic()); } llvm::Type *CodeGenTypes::GetFunctionTypeForVTable(GlobalDecl GD) { const CXXMethodDecl *MD = cast(GD.getDecl()); const FunctionProtoType *FPT = MD->getType()->getAs(); if (!isFuncTypeConvertible(FPT)) return llvm::StructType::get(getLLVMContext()); const CGFunctionInfo *Info; if (isa(MD)) Info = &arrangeCXXDestructor(cast(MD), GD.getDtorType()); else Info = &arrangeCXXMethodDeclaration(MD); return GetFunctionType(*Info); } void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI, const Decl *TargetDecl, AttributeListType &PAL, unsigned &CallingConv, bool AttrOnCallSite) { llvm::AttrBuilder FuncAttrs; llvm::AttrBuilder RetAttrs; CallingConv = FI.getEffectiveCallingConvention(); if (FI.isNoReturn()) FuncAttrs.addAttribute(llvm::Attribute::NoReturn); // FIXME: handle sseregparm someday... if (TargetDecl) { if (TargetDecl->hasAttr()) FuncAttrs.addAttribute(llvm::Attribute::ReturnsTwice); if (TargetDecl->hasAttr()) FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); if (TargetDecl->hasAttr()) FuncAttrs.addAttribute(llvm::Attribute::NoReturn); if (const FunctionDecl *Fn = dyn_cast(TargetDecl)) { const FunctionProtoType *FPT = Fn->getType()->getAs(); if (FPT && FPT->isNothrow(getContext())) FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); // Don't use [[noreturn]] or _Noreturn for a call to a virtual function. // These attributes are not inherited by overloads. const CXXMethodDecl *MD = dyn_cast(Fn); if (Fn->isNoReturn() && !(AttrOnCallSite && MD && MD->isVirtual())) FuncAttrs.addAttribute(llvm::Attribute::NoReturn); } // 'const' and 'pure' attribute functions are also nounwind. if (TargetDecl->hasAttr()) { FuncAttrs.addAttribute(llvm::Attribute::ReadNone); FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); } else if (TargetDecl->hasAttr()) { FuncAttrs.addAttribute(llvm::Attribute::ReadOnly); FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); } if (TargetDecl->hasAttr()) RetAttrs.addAttribute(llvm::Attribute::NoAlias); } if (CodeGenOpts.OptimizeSize) FuncAttrs.addAttribute(llvm::Attribute::OptimizeForSize); if (CodeGenOpts.OptimizeSize == 2) FuncAttrs.addAttribute(llvm::Attribute::MinSize); if (CodeGenOpts.DisableRedZone) FuncAttrs.addAttribute(llvm::Attribute::NoRedZone); if (CodeGenOpts.NoImplicitFloat) FuncAttrs.addAttribute(llvm::Attribute::NoImplicitFloat); if (AttrOnCallSite) { // Attributes that should go on the call site only. if (!CodeGenOpts.SimplifyLibCalls) FuncAttrs.addAttribute(llvm::Attribute::NoBuiltin); } else { // Attributes that should go on the function, but not the call site. if (!CodeGenOpts.DisableFPElim) { FuncAttrs.addAttribute("no-frame-pointer-elim", "false"); FuncAttrs.addAttribute("no-frame-pointer-elim-non-leaf", "false"); } else if (CodeGenOpts.OmitLeafFramePointer) { FuncAttrs.addAttribute("no-frame-pointer-elim", "false"); FuncAttrs.addAttribute("no-frame-pointer-elim-non-leaf", "true"); } else { FuncAttrs.addAttribute("no-frame-pointer-elim", "true"); FuncAttrs.addAttribute("no-frame-pointer-elim-non-leaf", "true"); } FuncAttrs.addAttribute("less-precise-fpmad", CodeGenOpts.LessPreciseFPMAD ? "true" : "false"); FuncAttrs.addAttribute("no-infs-fp-math", CodeGenOpts.NoInfsFPMath ? "true" : "false"); FuncAttrs.addAttribute("no-nans-fp-math", CodeGenOpts.NoNaNsFPMath ? "true" : "false"); FuncAttrs.addAttribute("unsafe-fp-math", CodeGenOpts.UnsafeFPMath ? "true" : "false"); FuncAttrs.addAttribute("use-soft-float", CodeGenOpts.SoftFloat ? "true" : "false"); } QualType RetTy = FI.getReturnType(); unsigned Index = 1; const ABIArgInfo &RetAI = FI.getReturnInfo(); switch (RetAI.getKind()) { case ABIArgInfo::Extend: if (RetTy->hasSignedIntegerRepresentation()) RetAttrs.addAttribute(llvm::Attribute::SExt); else if (RetTy->hasUnsignedIntegerRepresentation()) RetAttrs.addAttribute(llvm::Attribute::ZExt); break; case ABIArgInfo::Direct: case ABIArgInfo::Ignore: break; case ABIArgInfo::Indirect: { llvm::AttrBuilder SRETAttrs; SRETAttrs.addAttribute(llvm::Attribute::StructRet); if (RetAI.getInReg()) SRETAttrs.addAttribute(llvm::Attribute::InReg); PAL.push_back(llvm:: AttributeSet::get(getLLVMContext(), Index, SRETAttrs)); ++Index; // sret disables readnone and readonly FuncAttrs.removeAttribute(llvm::Attribute::ReadOnly) .removeAttribute(llvm::Attribute::ReadNone); break; } case ABIArgInfo::Expand: llvm_unreachable("Invalid ABI kind for return argument"); } if (RetAttrs.hasAttributes()) PAL.push_back(llvm:: AttributeSet::get(getLLVMContext(), llvm::AttributeSet::ReturnIndex, RetAttrs)); for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(), ie = FI.arg_end(); it != ie; ++it) { QualType ParamType = it->type; const ABIArgInfo &AI = it->info; llvm::AttrBuilder Attrs; if (AI.getPaddingType()) { if (AI.getPaddingInReg()) PAL.push_back(llvm::AttributeSet::get(getLLVMContext(), Index, llvm::Attribute::InReg)); // Increment Index if there is padding. ++Index; } // 'restrict' -> 'noalias' is done in EmitFunctionProlog when we // have the corresponding parameter variable. It doesn't make // sense to do it here because parameters are so messed up. switch (AI.getKind()) { case ABIArgInfo::Extend: if (ParamType->isSignedIntegerOrEnumerationType()) Attrs.addAttribute(llvm::Attribute::SExt); else if (ParamType->isUnsignedIntegerOrEnumerationType()) Attrs.addAttribute(llvm::Attribute::ZExt); // FALL THROUGH case ABIArgInfo::Direct: if (AI.getInReg()) Attrs.addAttribute(llvm::Attribute::InReg); // FIXME: handle sseregparm someday... if (llvm::StructType *STy = dyn_cast(AI.getCoerceToType())) { unsigned Extra = STy->getNumElements()-1; // 1 will be added below. if (Attrs.hasAttributes()) for (unsigned I = 0; I < Extra; ++I) PAL.push_back(llvm::AttributeSet::get(getLLVMContext(), Index + I, Attrs)); Index += Extra; } break; case ABIArgInfo::Indirect: if (AI.getInReg()) Attrs.addAttribute(llvm::Attribute::InReg); if (AI.getIndirectByVal()) Attrs.addAttribute(llvm::Attribute::ByVal); Attrs.addAlignmentAttr(AI.getIndirectAlign()); // byval disables readnone and readonly. FuncAttrs.removeAttribute(llvm::Attribute::ReadOnly) .removeAttribute(llvm::Attribute::ReadNone); break; case ABIArgInfo::Ignore: // Skip increment, no matching LLVM parameter. continue; case ABIArgInfo::Expand: { SmallVector types; // FIXME: This is rather inefficient. Do we ever actually need to do // anything here? The result should be just reconstructed on the other // side, so extension should be a non-issue. getTypes().GetExpandedTypes(ParamType, types); Index += types.size(); continue; } } if (Attrs.hasAttributes()) PAL.push_back(llvm::AttributeSet::get(getLLVMContext(), Index, Attrs)); ++Index; } if (FuncAttrs.hasAttributes()) PAL.push_back(llvm:: AttributeSet::get(getLLVMContext(), llvm::AttributeSet::FunctionIndex, FuncAttrs)); } /// An argument came in as a promoted argument; demote it back to its /// declared type. static llvm::Value *emitArgumentDemotion(CodeGenFunction &CGF, const VarDecl *var, llvm::Value *value) { llvm::Type *varType = CGF.ConvertType(var->getType()); // This can happen with promotions that actually don't change the // underlying type, like the enum promotions. if (value->getType() == varType) return value; assert((varType->isIntegerTy() || varType->isFloatingPointTy()) && "unexpected promotion type"); if (isa(varType)) return CGF.Builder.CreateTrunc(value, varType, "arg.unpromote"); return CGF.Builder.CreateFPCast(value, varType, "arg.unpromote"); } void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI, llvm::Function *Fn, const FunctionArgList &Args) { // If this is an implicit-return-zero function, go ahead and // initialize the return value. TODO: it might be nice to have // a more general mechanism for this that didn't require synthesized // return statements. if (const FunctionDecl *FD = dyn_cast_or_null(CurCodeDecl)) { if (FD->hasImplicitReturnZero()) { QualType RetTy = FD->getResultType().getUnqualifiedType(); llvm::Type* LLVMTy = CGM.getTypes().ConvertType(RetTy); llvm::Constant* Zero = llvm::Constant::getNullValue(LLVMTy); Builder.CreateStore(Zero, ReturnValue); } } // FIXME: We no longer need the types from FunctionArgList; lift up and // simplify. // Emit allocs for param decls. Give the LLVM Argument nodes names. llvm::Function::arg_iterator AI = Fn->arg_begin(); // Name the struct return argument. if (CGM.ReturnTypeUsesSRet(FI)) { AI->setName("agg.result"); AI->addAttr(llvm::AttributeSet::get(getLLVMContext(), AI->getArgNo() + 1, llvm::Attribute::NoAlias)); ++AI; } assert(FI.arg_size() == Args.size() && "Mismatch between function signature & arguments."); unsigned ArgNo = 1; CGFunctionInfo::const_arg_iterator info_it = FI.arg_begin(); for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); i != e; ++i, ++info_it, ++ArgNo) { const VarDecl *Arg = *i; QualType Ty = info_it->type; const ABIArgInfo &ArgI = info_it->info; bool isPromoted = isa(Arg) && cast(Arg)->isKNRPromoted(); // Skip the dummy padding argument. if (ArgI.getPaddingType()) ++AI; switch (ArgI.getKind()) { case ABIArgInfo::Indirect: { llvm::Value *V = AI; if (!hasScalarEvaluationKind(Ty)) { // Aggregates and complex variables are accessed by reference. All we // need to do is realign the value, if requested if (ArgI.getIndirectRealign()) { llvm::Value *AlignedTemp = CreateMemTemp(Ty, "coerce"); // Copy from the incoming argument pointer to the temporary with the // appropriate alignment. // // FIXME: We should have a common utility for generating an aggregate // copy. llvm::Type *I8PtrTy = Builder.getInt8PtrTy(); CharUnits Size = getContext().getTypeSizeInChars(Ty); llvm::Value *Dst = Builder.CreateBitCast(AlignedTemp, I8PtrTy); llvm::Value *Src = Builder.CreateBitCast(V, I8PtrTy); Builder.CreateMemCpy(Dst, Src, llvm::ConstantInt::get(IntPtrTy, Size.getQuantity()), ArgI.getIndirectAlign(), false); V = AlignedTemp; } } else { // Load scalar value from indirect argument. CharUnits Alignment = getContext().getTypeAlignInChars(Ty); V = EmitLoadOfScalar(V, false, Alignment.getQuantity(), Ty); if (isPromoted) V = emitArgumentDemotion(*this, Arg, V); } EmitParmDecl(*Arg, V, ArgNo); break; } case ABIArgInfo::Extend: case ABIArgInfo::Direct: { // If we have the trivial case, handle it with no muss and fuss. if (!isa(ArgI.getCoerceToType()) && ArgI.getCoerceToType() == ConvertType(Ty) && ArgI.getDirectOffset() == 0) { assert(AI != Fn->arg_end() && "Argument mismatch!"); llvm::Value *V = AI; if (Arg->getType().isRestrictQualified()) AI->addAttr(llvm::AttributeSet::get(getLLVMContext(), AI->getArgNo() + 1, llvm::Attribute::NoAlias)); // Ensure the argument is the correct type. if (V->getType() != ArgI.getCoerceToType()) V = Builder.CreateBitCast(V, ArgI.getCoerceToType()); if (isPromoted) V = emitArgumentDemotion(*this, Arg, V); // Because of merging of function types from multiple decls it is // possible for the type of an argument to not match the corresponding // type in the function type. Since we are codegening the callee // in here, add a cast to the argument type. llvm::Type *LTy = ConvertType(Arg->getType()); if (V->getType() != LTy) V = Builder.CreateBitCast(V, LTy); EmitParmDecl(*Arg, V, ArgNo); break; } llvm::AllocaInst *Alloca = CreateMemTemp(Ty, Arg->getName()); // The alignment we need to use is the max of the requested alignment for // the argument plus the alignment required by our access code below. unsigned AlignmentToUse = CGM.getDataLayout().getABITypeAlignment(ArgI.getCoerceToType()); AlignmentToUse = std::max(AlignmentToUse, (unsigned)getContext().getDeclAlign(Arg).getQuantity()); Alloca->setAlignment(AlignmentToUse); llvm::Value *V = Alloca; llvm::Value *Ptr = V; // Pointer to store into. // If the value is offset in memory, apply the offset now. if (unsigned Offs = ArgI.getDirectOffset()) { Ptr = Builder.CreateBitCast(Ptr, Builder.getInt8PtrTy()); Ptr = Builder.CreateConstGEP1_32(Ptr, Offs); Ptr = Builder.CreateBitCast(Ptr, llvm::PointerType::getUnqual(ArgI.getCoerceToType())); } // If the coerce-to type is a first class aggregate, we flatten it and // pass the elements. Either way is semantically identical, but fast-isel // and the optimizer generally likes scalar values better than FCAs. llvm::StructType *STy = dyn_cast(ArgI.getCoerceToType()); if (STy && STy->getNumElements() > 1) { uint64_t SrcSize = CGM.getDataLayout().getTypeAllocSize(STy); llvm::Type *DstTy = cast(Ptr->getType())->getElementType(); uint64_t DstSize = CGM.getDataLayout().getTypeAllocSize(DstTy); if (SrcSize <= DstSize) { Ptr = Builder.CreateBitCast(Ptr, llvm::PointerType::getUnqual(STy)); for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { assert(AI != Fn->arg_end() && "Argument mismatch!"); AI->setName(Arg->getName() + ".coerce" + Twine(i)); llvm::Value *EltPtr = Builder.CreateConstGEP2_32(Ptr, 0, i); Builder.CreateStore(AI++, EltPtr); } } else { llvm::AllocaInst *TempAlloca = CreateTempAlloca(ArgI.getCoerceToType(), "coerce"); TempAlloca->setAlignment(AlignmentToUse); llvm::Value *TempV = TempAlloca; for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { assert(AI != Fn->arg_end() && "Argument mismatch!"); AI->setName(Arg->getName() + ".coerce" + Twine(i)); llvm::Value *EltPtr = Builder.CreateConstGEP2_32(TempV, 0, i); Builder.CreateStore(AI++, EltPtr); } Builder.CreateMemCpy(Ptr, TempV, DstSize, AlignmentToUse); } } else { // Simple case, just do a coerced store of the argument into the alloca. assert(AI != Fn->arg_end() && "Argument mismatch!"); AI->setName(Arg->getName() + ".coerce"); CreateCoercedStore(AI++, Ptr, /*DestIsVolatile=*/false, *this); } // Match to what EmitParmDecl is expecting for this type. if (CodeGenFunction::hasScalarEvaluationKind(Ty)) { V = EmitLoadOfScalar(V, false, AlignmentToUse, Ty); if (isPromoted) V = emitArgumentDemotion(*this, Arg, V); } EmitParmDecl(*Arg, V, ArgNo); continue; // Skip ++AI increment, already done. } case ABIArgInfo::Expand: { // If this structure was expanded into multiple arguments then // we need to create a temporary and reconstruct it from the // arguments. llvm::AllocaInst *Alloca = CreateMemTemp(Ty); CharUnits Align = getContext().getDeclAlign(Arg); Alloca->setAlignment(Align.getQuantity()); LValue LV = MakeAddrLValue(Alloca, Ty, Align); llvm::Function::arg_iterator End = ExpandTypeFromArgs(Ty, LV, AI); EmitParmDecl(*Arg, Alloca, ArgNo); // Name the arguments used in expansion and increment AI. unsigned Index = 0; for (; AI != End; ++AI, ++Index) AI->setName(Arg->getName() + "." + Twine(Index)); continue; } case ABIArgInfo::Ignore: // Initialize the local variable appropriately. if (!hasScalarEvaluationKind(Ty)) EmitParmDecl(*Arg, CreateMemTemp(Ty), ArgNo); else EmitParmDecl(*Arg, llvm::UndefValue::get(ConvertType(Arg->getType())), ArgNo); // Skip increment, no matching LLVM parameter. continue; } ++AI; } assert(AI == Fn->arg_end() && "Argument mismatch!"); } static void eraseUnusedBitCasts(llvm::Instruction *insn) { while (insn->use_empty()) { llvm::BitCastInst *bitcast = dyn_cast(insn); if (!bitcast) return; // This is "safe" because we would have used a ConstantExpr otherwise. insn = cast(bitcast->getOperand(0)); bitcast->eraseFromParent(); } } /// Try to emit a fused autorelease of a return result. static llvm::Value *tryEmitFusedAutoreleaseOfResult(CodeGenFunction &CGF, llvm::Value *result) { // We must be immediately followed the cast. llvm::BasicBlock *BB = CGF.Builder.GetInsertBlock(); if (BB->empty()) return 0; if (&BB->back() != result) return 0; llvm::Type *resultType = result->getType(); // result is in a BasicBlock and is therefore an Instruction. llvm::Instruction *generator = cast(result); SmallVector insnsToKill; // Look for: // %generator = bitcast %type1* %generator2 to %type2* while (llvm::BitCastInst *bitcast = dyn_cast(generator)) { // We would have emitted this as a constant if the operand weren't // an Instruction. generator = cast(bitcast->getOperand(0)); // Require the generator to be immediately followed by the cast. if (generator->getNextNode() != bitcast) return 0; insnsToKill.push_back(bitcast); } // Look for: // %generator = call i8* @objc_retain(i8* %originalResult) // or // %generator = call i8* @objc_retainAutoreleasedReturnValue(i8* %originalResult) llvm::CallInst *call = dyn_cast(generator); if (!call) return 0; bool doRetainAutorelease; if (call->getCalledValue() == CGF.CGM.getARCEntrypoints().objc_retain) { doRetainAutorelease = true; } else if (call->getCalledValue() == CGF.CGM.getARCEntrypoints() .objc_retainAutoreleasedReturnValue) { doRetainAutorelease = false; // If we emitted an assembly marker for this call (and the // ARCEntrypoints field should have been set if so), go looking // for that call. If we can't find it, we can't do this // optimization. But it should always be the immediately previous // instruction, unless we needed bitcasts around the call. if (CGF.CGM.getARCEntrypoints().retainAutoreleasedReturnValueMarker) { llvm::Instruction *prev = call->getPrevNode(); assert(prev); if (isa(prev)) { prev = prev->getPrevNode(); assert(prev); } assert(isa(prev)); assert(cast(prev)->getCalledValue() == CGF.CGM.getARCEntrypoints().retainAutoreleasedReturnValueMarker); insnsToKill.push_back(prev); } } else { return 0; } result = call->getArgOperand(0); insnsToKill.push_back(call); // Keep killing bitcasts, for sanity. Note that we no longer care // about precise ordering as long as there's exactly one use. while (llvm::BitCastInst *bitcast = dyn_cast(result)) { if (!bitcast->hasOneUse()) break; insnsToKill.push_back(bitcast); result = bitcast->getOperand(0); } // Delete all the unnecessary instructions, from latest to earliest. for (SmallVectorImpl::iterator i = insnsToKill.begin(), e = insnsToKill.end(); i != e; ++i) (*i)->eraseFromParent(); // Do the fused retain/autorelease if we were asked to. if (doRetainAutorelease) result = CGF.EmitARCRetainAutoreleaseReturnValue(result); // Cast back to the result type. return CGF.Builder.CreateBitCast(result, resultType); } /// If this is a +1 of the value of an immutable 'self', remove it. static llvm::Value *tryRemoveRetainOfSelf(CodeGenFunction &CGF, llvm::Value *result) { // This is only applicable to a method with an immutable 'self'. const ObjCMethodDecl *method = dyn_cast_or_null(CGF.CurCodeDecl); if (!method) return 0; const VarDecl *self = method->getSelfDecl(); if (!self->getType().isConstQualified()) return 0; // Look for a retain call. llvm::CallInst *retainCall = dyn_cast(result->stripPointerCasts()); if (!retainCall || retainCall->getCalledValue() != CGF.CGM.getARCEntrypoints().objc_retain) return 0; // Look for an ordinary load of 'self'. llvm::Value *retainedValue = retainCall->getArgOperand(0); llvm::LoadInst *load = dyn_cast(retainedValue->stripPointerCasts()); if (!load || load->isAtomic() || load->isVolatile() || load->getPointerOperand() != CGF.GetAddrOfLocalVar(self)) return 0; // Okay! Burn it all down. This relies for correctness on the // assumption that the retain is emitted as part of the return and // that thereafter everything is used "linearly". llvm::Type *resultType = result->getType(); eraseUnusedBitCasts(cast(result)); assert(retainCall->use_empty()); retainCall->eraseFromParent(); eraseUnusedBitCasts(cast(retainedValue)); return CGF.Builder.CreateBitCast(load, resultType); } /// Emit an ARC autorelease of the result of a function. /// /// \return the value to actually return from the function static llvm::Value *emitAutoreleaseOfResult(CodeGenFunction &CGF, llvm::Value *result) { // If we're returning 'self', kill the initial retain. This is a // heuristic attempt to "encourage correctness" in the really unfortunate // case where we have a return of self during a dealloc and we desperately // need to avoid the possible autorelease. if (llvm::Value *self = tryRemoveRetainOfSelf(CGF, result)) return self; // At -O0, try to emit a fused retain/autorelease. if (CGF.shouldUseFusedARCCalls()) if (llvm::Value *fused = tryEmitFusedAutoreleaseOfResult(CGF, result)) return fused; return CGF.EmitARCAutoreleaseReturnValue(result); } /// Heuristically search for a dominating store to the return-value slot. static llvm::StoreInst *findDominatingStoreToReturnValue(CodeGenFunction &CGF) { // If there are multiple uses of the return-value slot, just check // for something immediately preceding the IP. Sometimes this can // happen with how we generate implicit-returns; it can also happen // with noreturn cleanups. if (!CGF.ReturnValue->hasOneUse()) { llvm::BasicBlock *IP = CGF.Builder.GetInsertBlock(); if (IP->empty()) return 0; llvm::StoreInst *store = dyn_cast(&IP->back()); if (!store) return 0; if (store->getPointerOperand() != CGF.ReturnValue) return 0; assert(!store->isAtomic() && !store->isVolatile()); // see below return store; } llvm::StoreInst *store = dyn_cast(CGF.ReturnValue->use_back()); if (!store) return 0; // These aren't actually possible for non-coerced returns, and we // only care about non-coerced returns on this code path. assert(!store->isAtomic() && !store->isVolatile()); // Now do a first-and-dirty dominance check: just walk up the // single-predecessors chain from the current insertion point. llvm::BasicBlock *StoreBB = store->getParent(); llvm::BasicBlock *IP = CGF.Builder.GetInsertBlock(); while (IP != StoreBB) { if (!(IP = IP->getSinglePredecessor())) return 0; } // Okay, the store's basic block dominates the insertion point; we // can do our thing. return store; } /// Check whether 'this' argument of a callsite matches 'this' of the caller. static bool checkThisPointer(llvm::Value *ThisArg, llvm::Value *This) { if (ThisArg == This) return true; // Check whether ThisArg is a bitcast of This. llvm::BitCastInst *Bitcast; if ((Bitcast = dyn_cast(ThisArg)) && Bitcast->getOperand(0) == This) return true; return false; } void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI, bool EmitRetDbgLoc) { // Functions with no result always return void. if (ReturnValue == 0) { Builder.CreateRetVoid(); return; } llvm::DebugLoc RetDbgLoc; llvm::Value *RV = 0; QualType RetTy = FI.getReturnType(); const ABIArgInfo &RetAI = FI.getReturnInfo(); switch (RetAI.getKind()) { case ABIArgInfo::Indirect: { switch (getEvaluationKind(RetTy)) { case TEK_Complex: { ComplexPairTy RT = EmitLoadOfComplex(MakeNaturalAlignAddrLValue(ReturnValue, RetTy)); EmitStoreOfComplex(RT, MakeNaturalAlignAddrLValue(CurFn->arg_begin(), RetTy), /*isInit*/ true); break; } case TEK_Aggregate: // Do nothing; aggregrates get evaluated directly into the destination. break; case TEK_Scalar: EmitStoreOfScalar(Builder.CreateLoad(ReturnValue), MakeNaturalAlignAddrLValue(CurFn->arg_begin(), RetTy), /*isInit*/ true); break; } break; } case ABIArgInfo::Extend: case ABIArgInfo::Direct: if (RetAI.getCoerceToType() == ConvertType(RetTy) && RetAI.getDirectOffset() == 0) { // The internal return value temp always will have pointer-to-return-type // type, just do a load. // If there is a dominating store to ReturnValue, we can elide // the load, zap the store, and usually zap the alloca. if (llvm::StoreInst *SI = findDominatingStoreToReturnValue(*this)) { // Reuse the debug location from the store unless we're told not to. if (EmitRetDbgLoc) RetDbgLoc = SI->getDebugLoc(); // Get the stored value and nuke the now-dead store. RV = SI->getValueOperand(); SI->eraseFromParent(); // If that was the only use of the return value, nuke it as well now. if (ReturnValue->use_empty() && isa(ReturnValue)) { cast(ReturnValue)->eraseFromParent(); ReturnValue = 0; } // Otherwise, we have to do a simple load. } else { RV = Builder.CreateLoad(ReturnValue); } } else { llvm::Value *V = ReturnValue; // If the value is offset in memory, apply the offset now. if (unsigned Offs = RetAI.getDirectOffset()) { V = Builder.CreateBitCast(V, Builder.getInt8PtrTy()); V = Builder.CreateConstGEP1_32(V, Offs); V = Builder.CreateBitCast(V, llvm::PointerType::getUnqual(RetAI.getCoerceToType())); } RV = CreateCoercedLoad(V, RetAI.getCoerceToType(), *this); } // In ARC, end functions that return a retainable type with a call // to objc_autoreleaseReturnValue. if (AutoreleaseResult) { assert(getLangOpts().ObjCAutoRefCount && !FI.isReturnsRetained() && RetTy->isObjCRetainableType()); RV = emitAutoreleaseOfResult(*this, RV); } break; case ABIArgInfo::Ignore: break; case ABIArgInfo::Expand: llvm_unreachable("Invalid ABI kind for return argument"); } // If this function returns 'this', the last instruction is a CallInst // that returns 'this', and 'this' argument of the CallInst points to // the same object as CXXThisValue, use the return value from the CallInst. // We will not need to keep 'this' alive through the callsite. It also enables // optimizations in the backend, such as tail call optimization. if (CalleeWithThisReturn && CGM.getCXXABI().HasThisReturn(CurGD)) { llvm::BasicBlock *IP = Builder.GetInsertBlock(); llvm::CallInst *Callsite; if (!IP->empty() && (Callsite = dyn_cast(&IP->back())) && Callsite->getCalledFunction() == CalleeWithThisReturn && checkThisPointer(Callsite->getOperand(0), CXXThisValue)) RV = Builder.CreateBitCast(Callsite, RetAI.getCoerceToType()); } llvm::Instruction *Ret = RV ? Builder.CreateRet(RV) : Builder.CreateRetVoid(); if (!RetDbgLoc.isUnknown()) Ret->setDebugLoc(RetDbgLoc); } void CodeGenFunction::EmitDelegateCallArg(CallArgList &args, const VarDecl *param) { // StartFunction converted the ABI-lowered parameter(s) into a // local alloca. We need to turn that into an r-value suitable // for EmitCall. llvm::Value *local = GetAddrOfLocalVar(param); QualType type = param->getType(); // For the most part, we just need to load the alloca, except: // 1) aggregate r-values are actually pointers to temporaries, and // 2) references to non-scalars are pointers directly to the aggregate. // I don't know why references to scalars are different here. if (const ReferenceType *ref = type->getAs()) { if (!hasScalarEvaluationKind(ref->getPointeeType())) return args.add(RValue::getAggregate(local), type); // Locals which are references to scalars are represented // with allocas holding the pointer. return args.add(RValue::get(Builder.CreateLoad(local)), type); } args.add(convertTempToRValue(local, type), type); } static bool isProvablyNull(llvm::Value *addr) { return isa(addr); } static bool isProvablyNonNull(llvm::Value *addr) { return isa(addr); } /// Emit the actual writing-back of a writeback. static void emitWriteback(CodeGenFunction &CGF, const CallArgList::Writeback &writeback) { const LValue &srcLV = writeback.Source; llvm::Value *srcAddr = srcLV.getAddress(); assert(!isProvablyNull(srcAddr) && "shouldn't have writeback for provably null argument"); llvm::BasicBlock *contBB = 0; // If the argument wasn't provably non-null, we need to null check // before doing the store. bool provablyNonNull = isProvablyNonNull(srcAddr); if (!provablyNonNull) { llvm::BasicBlock *writebackBB = CGF.createBasicBlock("icr.writeback"); contBB = CGF.createBasicBlock("icr.done"); llvm::Value *isNull = CGF.Builder.CreateIsNull(srcAddr, "icr.isnull"); CGF.Builder.CreateCondBr(isNull, contBB, writebackBB); CGF.EmitBlock(writebackBB); } // Load the value to writeback. llvm::Value *value = CGF.Builder.CreateLoad(writeback.Temporary); // Cast it back, in case we're writing an id to a Foo* or something. value = CGF.Builder.CreateBitCast(value, cast(srcAddr->getType())->getElementType(), "icr.writeback-cast"); // Perform the writeback. // If we have a "to use" value, it's something we need to emit a use // of. This has to be carefully threaded in: if it's done after the // release it's potentially undefined behavior (and the optimizer // will ignore it), and if it happens before the retain then the // optimizer could move the release there. if (writeback.ToUse) { assert(srcLV.getObjCLifetime() == Qualifiers::OCL_Strong); // Retain the new value. No need to block-copy here: the block's // being passed up the stack. value = CGF.EmitARCRetainNonBlock(value); // Emit the intrinsic use here. CGF.EmitARCIntrinsicUse(writeback.ToUse); // Load the old value (primitively). llvm::Value *oldValue = CGF.EmitLoadOfScalar(srcLV); // Put the new value in place (primitively). CGF.EmitStoreOfScalar(value, srcLV, /*init*/ false); // Release the old value. CGF.EmitARCRelease(oldValue, srcLV.isARCPreciseLifetime()); // Otherwise, we can just do a normal lvalue store. } else { CGF.EmitStoreThroughLValue(RValue::get(value), srcLV); } // Jump to the continuation block. if (!provablyNonNull) CGF.EmitBlock(contBB); } static void emitWritebacks(CodeGenFunction &CGF, const CallArgList &args) { for (CallArgList::writeback_iterator i = args.writeback_begin(), e = args.writeback_end(); i != e; ++i) emitWriteback(CGF, *i); } static const Expr *maybeGetUnaryAddrOfOperand(const Expr *E) { if (const UnaryOperator *uop = dyn_cast(E->IgnoreParens())) if (uop->getOpcode() == UO_AddrOf) return uop->getSubExpr(); return 0; } /// Emit an argument that's being passed call-by-writeback. That is, /// we are passing the address of static void emitWritebackArg(CodeGenFunction &CGF, CallArgList &args, const ObjCIndirectCopyRestoreExpr *CRE) { LValue srcLV; // Make an optimistic effort to emit the address as an l-value. // This can fail if the the argument expression is more complicated. if (const Expr *lvExpr = maybeGetUnaryAddrOfOperand(CRE->getSubExpr())) { srcLV = CGF.EmitLValue(lvExpr); // Otherwise, just emit it as a scalar. } else { llvm::Value *srcAddr = CGF.EmitScalarExpr(CRE->getSubExpr()); QualType srcAddrType = CRE->getSubExpr()->getType()->castAs()->getPointeeType(); srcLV = CGF.MakeNaturalAlignAddrLValue(srcAddr, srcAddrType); } llvm::Value *srcAddr = srcLV.getAddress(); // The dest and src types don't necessarily match in LLVM terms // because of the crazy ObjC compatibility rules. llvm::PointerType *destType = cast(CGF.ConvertType(CRE->getType())); // If the address is a constant null, just pass the appropriate null. if (isProvablyNull(srcAddr)) { args.add(RValue::get(llvm::ConstantPointerNull::get(destType)), CRE->getType()); return; } // Create the temporary. llvm::Value *temp = CGF.CreateTempAlloca(destType->getElementType(), "icr.temp"); // Loading an l-value can introduce a cleanup if the l-value is __weak, // and that cleanup will be conditional if we can't prove that the l-value // isn't null, so we need to register a dominating point so that the cleanups // system will make valid IR. CodeGenFunction::ConditionalEvaluation condEval(CGF); // Zero-initialize it if we're not doing a copy-initialization. bool shouldCopy = CRE->shouldCopy(); if (!shouldCopy) { llvm::Value *null = llvm::ConstantPointerNull::get( cast(destType->getElementType())); CGF.Builder.CreateStore(null, temp); } llvm::BasicBlock *contBB = 0; llvm::BasicBlock *originBB = 0; // If the address is *not* known to be non-null, we need to switch. llvm::Value *finalArgument; bool provablyNonNull = isProvablyNonNull(srcAddr); if (provablyNonNull) { finalArgument = temp; } else { llvm::Value *isNull = CGF.Builder.CreateIsNull(srcAddr, "icr.isnull"); finalArgument = CGF.Builder.CreateSelect(isNull, llvm::ConstantPointerNull::get(destType), temp, "icr.argument"); // If we need to copy, then the load has to be conditional, which // means we need control flow. if (shouldCopy) { originBB = CGF.Builder.GetInsertBlock(); contBB = CGF.createBasicBlock("icr.cont"); llvm::BasicBlock *copyBB = CGF.createBasicBlock("icr.copy"); CGF.Builder.CreateCondBr(isNull, contBB, copyBB); CGF.EmitBlock(copyBB); condEval.begin(CGF); } } llvm::Value *valueToUse = 0; // Perform a copy if necessary. if (shouldCopy) { RValue srcRV = CGF.EmitLoadOfLValue(srcLV); assert(srcRV.isScalar()); llvm::Value *src = srcRV.getScalarVal(); src = CGF.Builder.CreateBitCast(src, destType->getElementType(), "icr.cast"); // Use an ordinary store, not a store-to-lvalue. CGF.Builder.CreateStore(src, temp); // If optimization is enabled, and the value was held in a // __strong variable, we need to tell the optimizer that this // value has to stay alive until we're doing the store back. // This is because the temporary is effectively unretained, // and so otherwise we can violate the high-level semantics. if (CGF.CGM.getCodeGenOpts().OptimizationLevel != 0 && srcLV.getObjCLifetime() == Qualifiers::OCL_Strong) { valueToUse = src; } } // Finish the control flow if we needed it. if (shouldCopy && !provablyNonNull) { llvm::BasicBlock *copyBB = CGF.Builder.GetInsertBlock(); CGF.EmitBlock(contBB); // Make a phi for the value to intrinsically use. if (valueToUse) { llvm::PHINode *phiToUse = CGF.Builder.CreatePHI(valueToUse->getType(), 2, "icr.to-use"); phiToUse->addIncoming(valueToUse, copyBB); phiToUse->addIncoming(llvm::UndefValue::get(valueToUse->getType()), originBB); valueToUse = phiToUse; } condEval.end(CGF); } args.addWriteback(srcLV, temp, valueToUse); args.add(RValue::get(finalArgument), CRE->getType()); } void CodeGenFunction::EmitCallArg(CallArgList &args, const Expr *E, QualType type) { if (const ObjCIndirectCopyRestoreExpr *CRE = dyn_cast(E)) { assert(getLangOpts().ObjCAutoRefCount); assert(getContext().hasSameType(E->getType(), type)); return emitWritebackArg(*this, args, CRE); } assert(type->isReferenceType() == E->isGLValue() && "reference binding to unmaterialized r-value!"); if (E->isGLValue()) { assert(E->getObjectKind() == OK_Ordinary); return args.add(EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0), type); } if (hasAggregateEvaluationKind(type) && isa(E) && cast(E)->getCastKind() == CK_LValueToRValue) { LValue L = EmitLValue(cast(E)->getSubExpr()); assert(L.isSimple()); args.add(L.asAggregateRValue(), type, /*NeedsCopy*/true); return; } args.add(EmitAnyExprToTemp(E), type); } // In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC // optimizer it can aggressively ignore unwind edges. void CodeGenFunction::AddObjCARCExceptionMetadata(llvm::Instruction *Inst) { if (CGM.getCodeGenOpts().OptimizationLevel != 0 && !CGM.getCodeGenOpts().ObjCAutoRefCountExceptions) Inst->setMetadata("clang.arc.no_objc_arc_exceptions", CGM.getNoObjCARCExceptionsMetadata()); } /// Emits a call to the given no-arguments nounwind runtime function. llvm::CallInst * CodeGenFunction::EmitNounwindRuntimeCall(llvm::Value *callee, const llvm::Twine &name) { return EmitNounwindRuntimeCall(callee, ArrayRef(), name); } /// Emits a call to the given nounwind runtime function. llvm::CallInst * CodeGenFunction::EmitNounwindRuntimeCall(llvm::Value *callee, ArrayRef args, const llvm::Twine &name) { llvm::CallInst *call = EmitRuntimeCall(callee, args, name); call->setDoesNotThrow(); return call; } /// Emits a simple call (never an invoke) to the given no-arguments /// runtime function. llvm::CallInst * CodeGenFunction::EmitRuntimeCall(llvm::Value *callee, const llvm::Twine &name) { return EmitRuntimeCall(callee, ArrayRef(), name); } /// Emits a simple call (never an invoke) to the given runtime /// function. llvm::CallInst * CodeGenFunction::EmitRuntimeCall(llvm::Value *callee, ArrayRef args, const llvm::Twine &name) { llvm::CallInst *call = Builder.CreateCall(callee, args, name); call->setCallingConv(getRuntimeCC()); return call; } /// Emits a call or invoke to the given noreturn runtime function. void CodeGenFunction::EmitNoreturnRuntimeCallOrInvoke(llvm::Value *callee, ArrayRef args) { if (getInvokeDest()) { llvm::InvokeInst *invoke = Builder.CreateInvoke(callee, getUnreachableBlock(), getInvokeDest(), args); invoke->setDoesNotReturn(); invoke->setCallingConv(getRuntimeCC()); } else { llvm::CallInst *call = Builder.CreateCall(callee, args); call->setDoesNotReturn(); call->setCallingConv(getRuntimeCC()); Builder.CreateUnreachable(); } } /// Emits a call or invoke instruction to the given nullary runtime /// function. llvm::CallSite CodeGenFunction::EmitRuntimeCallOrInvoke(llvm::Value *callee, const Twine &name) { return EmitRuntimeCallOrInvoke(callee, ArrayRef(), name); } /// Emits a call or invoke instruction to the given runtime function. llvm::CallSite CodeGenFunction::EmitRuntimeCallOrInvoke(llvm::Value *callee, ArrayRef args, const Twine &name) { llvm::CallSite callSite = EmitCallOrInvoke(callee, args, name); callSite.setCallingConv(getRuntimeCC()); return callSite; } llvm::CallSite CodeGenFunction::EmitCallOrInvoke(llvm::Value *Callee, const Twine &Name) { return EmitCallOrInvoke(Callee, ArrayRef(), Name); } /// Emits a call or invoke instruction to the given function, depending /// on the current state of the EH stack. llvm::CallSite CodeGenFunction::EmitCallOrInvoke(llvm::Value *Callee, ArrayRef Args, const Twine &Name) { llvm::BasicBlock *InvokeDest = getInvokeDest(); llvm::Instruction *Inst; if (!InvokeDest) Inst = Builder.CreateCall(Callee, Args, Name); else { llvm::BasicBlock *ContBB = createBasicBlock("invoke.cont"); Inst = Builder.CreateInvoke(Callee, ContBB, InvokeDest, Args, Name); EmitBlock(ContBB); } // In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC // optimizer it can aggressively ignore unwind edges. if (CGM.getLangOpts().ObjCAutoRefCount) AddObjCARCExceptionMetadata(Inst); return Inst; } static void checkArgMatches(llvm::Value *Elt, unsigned &ArgNo, llvm::FunctionType *FTy) { if (ArgNo < FTy->getNumParams()) assert(Elt->getType() == FTy->getParamType(ArgNo)); else assert(FTy->isVarArg()); ++ArgNo; } void CodeGenFunction::ExpandTypeToArgs(QualType Ty, RValue RV, SmallVector &Args, llvm::FunctionType *IRFuncTy) { if (const ConstantArrayType *AT = getContext().getAsConstantArrayType(Ty)) { unsigned NumElts = AT->getSize().getZExtValue(); QualType EltTy = AT->getElementType(); llvm::Value *Addr = RV.getAggregateAddr(); for (unsigned Elt = 0; Elt < NumElts; ++Elt) { llvm::Value *EltAddr = Builder.CreateConstGEP2_32(Addr, 0, Elt); RValue EltRV = convertTempToRValue(EltAddr, EltTy); ExpandTypeToArgs(EltTy, EltRV, Args, IRFuncTy); } } else if (const RecordType *RT = Ty->getAs()) { RecordDecl *RD = RT->getDecl(); assert(RV.isAggregate() && "Unexpected rvalue during struct expansion"); LValue LV = MakeAddrLValue(RV.getAggregateAddr(), Ty); if (RD->isUnion()) { const FieldDecl *LargestFD = 0; CharUnits UnionSize = CharUnits::Zero(); for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { const FieldDecl *FD = *i; assert(!FD->isBitField() && "Cannot expand structure with bit-field members."); CharUnits FieldSize = getContext().getTypeSizeInChars(FD->getType()); if (UnionSize < FieldSize) { UnionSize = FieldSize; LargestFD = FD; } } if (LargestFD) { RValue FldRV = EmitRValueForField(LV, LargestFD); ExpandTypeToArgs(LargestFD->getType(), FldRV, Args, IRFuncTy); } } else { for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { FieldDecl *FD = *i; RValue FldRV = EmitRValueForField(LV, FD); ExpandTypeToArgs(FD->getType(), FldRV, Args, IRFuncTy); } } } else if (Ty->isAnyComplexType()) { ComplexPairTy CV = RV.getComplexVal(); Args.push_back(CV.first); Args.push_back(CV.second); } else { assert(RV.isScalar() && "Unexpected non-scalar rvalue during struct expansion."); // Insert a bitcast as needed. llvm::Value *V = RV.getScalarVal(); if (Args.size() < IRFuncTy->getNumParams() && V->getType() != IRFuncTy->getParamType(Args.size())) V = Builder.CreateBitCast(V, IRFuncTy->getParamType(Args.size())); Args.push_back(V); } } RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo, llvm::Value *Callee, ReturnValueSlot ReturnValue, const CallArgList &CallArgs, const Decl *TargetDecl, llvm::Instruction **callOrInvoke) { // FIXME: We no longer need the types from CallArgs; lift up and simplify. SmallVector Args; // Handle struct-return functions by passing a pointer to the // location that we would like to return into. QualType RetTy = CallInfo.getReturnType(); const ABIArgInfo &RetAI = CallInfo.getReturnInfo(); // IRArgNo - Keep track of the argument number in the callee we're looking at. unsigned IRArgNo = 0; llvm::FunctionType *IRFuncTy = cast( cast(Callee->getType())->getElementType()); // If the call returns a temporary with struct return, create a temporary // alloca to hold the result, unless one is given to us. if (CGM.ReturnTypeUsesSRet(CallInfo)) { llvm::Value *Value = ReturnValue.getValue(); if (!Value) Value = CreateMemTemp(RetTy); Args.push_back(Value); checkArgMatches(Value, IRArgNo, IRFuncTy); } assert(CallInfo.arg_size() == CallArgs.size() && "Mismatch between function signature & arguments."); CGFunctionInfo::const_arg_iterator info_it = CallInfo.arg_begin(); for (CallArgList::const_iterator I = CallArgs.begin(), E = CallArgs.end(); I != E; ++I, ++info_it) { const ABIArgInfo &ArgInfo = info_it->info; RValue RV = I->RV; CharUnits TypeAlign = getContext().getTypeAlignInChars(I->Ty); // Insert a padding argument to ensure proper alignment. if (llvm::Type *PaddingType = ArgInfo.getPaddingType()) { Args.push_back(llvm::UndefValue::get(PaddingType)); ++IRArgNo; } switch (ArgInfo.getKind()) { case ABIArgInfo::Indirect: { if (RV.isScalar() || RV.isComplex()) { // Make a temporary alloca to pass the argument. llvm::AllocaInst *AI = CreateMemTemp(I->Ty); if (ArgInfo.getIndirectAlign() > AI->getAlignment()) AI->setAlignment(ArgInfo.getIndirectAlign()); Args.push_back(AI); LValue argLV = MakeAddrLValue(Args.back(), I->Ty, TypeAlign); if (RV.isScalar()) EmitStoreOfScalar(RV.getScalarVal(), argLV, /*init*/ true); else EmitStoreOfComplex(RV.getComplexVal(), argLV, /*init*/ true); // Validate argument match. checkArgMatches(AI, IRArgNo, IRFuncTy); } else { // We want to avoid creating an unnecessary temporary+copy here; // however, we need one in three cases: // 1. If the argument is not byval, and we are required to copy the // source. (This case doesn't occur on any common architecture.) // 2. If the argument is byval, RV is not sufficiently aligned, and // we cannot force it to be sufficiently aligned. // 3. If the argument is byval, but RV is located in an address space // different than that of the argument (0). llvm::Value *Addr = RV.getAggregateAddr(); unsigned Align = ArgInfo.getIndirectAlign(); const llvm::DataLayout *TD = &CGM.getDataLayout(); const unsigned RVAddrSpace = Addr->getType()->getPointerAddressSpace(); const unsigned ArgAddrSpace = (IRArgNo < IRFuncTy->getNumParams() ? IRFuncTy->getParamType(IRArgNo)->getPointerAddressSpace() : 0); if ((!ArgInfo.getIndirectByVal() && I->NeedsCopy) || (ArgInfo.getIndirectByVal() && TypeAlign.getQuantity() < Align && llvm::getOrEnforceKnownAlignment(Addr, Align, TD) < Align) || (ArgInfo.getIndirectByVal() && (RVAddrSpace != ArgAddrSpace))) { // Create an aligned temporary, and copy to it. llvm::AllocaInst *AI = CreateMemTemp(I->Ty); if (Align > AI->getAlignment()) AI->setAlignment(Align); Args.push_back(AI); EmitAggregateCopy(AI, Addr, I->Ty, RV.isVolatileQualified()); // Validate argument match. checkArgMatches(AI, IRArgNo, IRFuncTy); } else { // Skip the extra memcpy call. Args.push_back(Addr); // Validate argument match. checkArgMatches(Addr, IRArgNo, IRFuncTy); } } break; } case ABIArgInfo::Ignore: break; case ABIArgInfo::Extend: case ABIArgInfo::Direct: { if (!isa(ArgInfo.getCoerceToType()) && ArgInfo.getCoerceToType() == ConvertType(info_it->type) && ArgInfo.getDirectOffset() == 0) { llvm::Value *V; if (RV.isScalar()) V = RV.getScalarVal(); else V = Builder.CreateLoad(RV.getAggregateAddr()); // If the argument doesn't match, perform a bitcast to coerce it. This // can happen due to trivial type mismatches. if (IRArgNo < IRFuncTy->getNumParams() && V->getType() != IRFuncTy->getParamType(IRArgNo)) V = Builder.CreateBitCast(V, IRFuncTy->getParamType(IRArgNo)); Args.push_back(V); checkArgMatches(V, IRArgNo, IRFuncTy); break; } // FIXME: Avoid the conversion through memory if possible. llvm::Value *SrcPtr; if (RV.isScalar() || RV.isComplex()) { SrcPtr = CreateMemTemp(I->Ty, "coerce"); LValue SrcLV = MakeAddrLValue(SrcPtr, I->Ty, TypeAlign); if (RV.isScalar()) { EmitStoreOfScalar(RV.getScalarVal(), SrcLV, /*init*/ true); } else { EmitStoreOfComplex(RV.getComplexVal(), SrcLV, /*init*/ true); } } else SrcPtr = RV.getAggregateAddr(); // If the value is offset in memory, apply the offset now. if (unsigned Offs = ArgInfo.getDirectOffset()) { SrcPtr = Builder.CreateBitCast(SrcPtr, Builder.getInt8PtrTy()); SrcPtr = Builder.CreateConstGEP1_32(SrcPtr, Offs); SrcPtr = Builder.CreateBitCast(SrcPtr, llvm::PointerType::getUnqual(ArgInfo.getCoerceToType())); } // If the coerce-to type is a first class aggregate, we flatten it and // pass the elements. Either way is semantically identical, but fast-isel // and the optimizer generally likes scalar values better than FCAs. if (llvm::StructType *STy = dyn_cast(ArgInfo.getCoerceToType())) { llvm::Type *SrcTy = cast(SrcPtr->getType())->getElementType(); uint64_t SrcSize = CGM.getDataLayout().getTypeAllocSize(SrcTy); uint64_t DstSize = CGM.getDataLayout().getTypeAllocSize(STy); // If the source type is smaller than the destination type of the // coerce-to logic, copy the source value into a temp alloca the size // of the destination type to allow loading all of it. The bits past // the source value are left undef. if (SrcSize < DstSize) { llvm::AllocaInst *TempAlloca = CreateTempAlloca(STy, SrcPtr->getName() + ".coerce"); Builder.CreateMemCpy(TempAlloca, SrcPtr, SrcSize, 0); SrcPtr = TempAlloca; } else { SrcPtr = Builder.CreateBitCast(SrcPtr, llvm::PointerType::getUnqual(STy)); } for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { llvm::Value *EltPtr = Builder.CreateConstGEP2_32(SrcPtr, 0, i); llvm::LoadInst *LI = Builder.CreateLoad(EltPtr); // We don't know what we're loading from. LI->setAlignment(1); Args.push_back(LI); // Validate argument match. checkArgMatches(LI, IRArgNo, IRFuncTy); } } else { // In the simple case, just pass the coerced loaded value. Args.push_back(CreateCoercedLoad(SrcPtr, ArgInfo.getCoerceToType(), *this)); // Validate argument match. checkArgMatches(Args.back(), IRArgNo, IRFuncTy); } break; } case ABIArgInfo::Expand: ExpandTypeToArgs(I->Ty, RV, Args, IRFuncTy); IRArgNo = Args.size(); break; } } // If the callee is a bitcast of a function to a varargs pointer to function // type, check to see if we can remove the bitcast. This handles some cases // with unprototyped functions. if (llvm::ConstantExpr *CE = dyn_cast(Callee)) if (llvm::Function *CalleeF = dyn_cast(CE->getOperand(0))) { llvm::PointerType *CurPT=cast(Callee->getType()); llvm::FunctionType *CurFT = cast(CurPT->getElementType()); llvm::FunctionType *ActualFT = CalleeF->getFunctionType(); if (CE->getOpcode() == llvm::Instruction::BitCast && ActualFT->getReturnType() == CurFT->getReturnType() && ActualFT->getNumParams() == CurFT->getNumParams() && ActualFT->getNumParams() == Args.size() && (CurFT->isVarArg() || !ActualFT->isVarArg())) { bool ArgsMatch = true; for (unsigned i = 0, e = ActualFT->getNumParams(); i != e; ++i) if (ActualFT->getParamType(i) != CurFT->getParamType(i)) { ArgsMatch = false; break; } // Strip the cast if we can get away with it. This is a nice cleanup, // but also allows us to inline the function at -O0 if it is marked // always_inline. if (ArgsMatch) Callee = CalleeF; } } unsigned CallingConv; CodeGen::AttributeListType AttributeList; CGM.ConstructAttributeList(CallInfo, TargetDecl, AttributeList, CallingConv, true); llvm::AttributeSet Attrs = llvm::AttributeSet::get(getLLVMContext(), AttributeList); llvm::BasicBlock *InvokeDest = 0; if (!Attrs.hasAttribute(llvm::AttributeSet::FunctionIndex, llvm::Attribute::NoUnwind)) InvokeDest = getInvokeDest(); llvm::CallSite CS; if (!InvokeDest) { CS = Builder.CreateCall(Callee, Args); } else { llvm::BasicBlock *Cont = createBasicBlock("invoke.cont"); CS = Builder.CreateInvoke(Callee, Cont, InvokeDest, Args); EmitBlock(Cont); } if (callOrInvoke) *callOrInvoke = CS.getInstruction(); CS.setAttributes(Attrs); CS.setCallingConv(static_cast(CallingConv)); // In ObjC ARC mode with no ObjC ARC exception safety, tell the ARC // optimizer it can aggressively ignore unwind edges. if (CGM.getLangOpts().ObjCAutoRefCount) AddObjCARCExceptionMetadata(CS.getInstruction()); // If the call doesn't return, finish the basic block and clear the // insertion point; this allows the rest of IRgen to discard // unreachable code. if (CS.doesNotReturn()) { Builder.CreateUnreachable(); Builder.ClearInsertionPoint(); // FIXME: For now, emit a dummy basic block because expr emitters in // generally are not ready to handle emitting expressions at unreachable // points. EnsureInsertPoint(); // Return a reasonable RValue. return GetUndefRValue(RetTy); } llvm::Instruction *CI = CS.getInstruction(); if (Builder.isNamePreserving() && !CI->getType()->isVoidTy()) CI->setName("call"); // Emit any writebacks immediately. Arguably this should happen // after any return-value munging. if (CallArgs.hasWritebacks()) emitWritebacks(*this, CallArgs); switch (RetAI.getKind()) { case ABIArgInfo::Indirect: return convertTempToRValue(Args[0], RetTy); case ABIArgInfo::Ignore: // If we are ignoring an argument that had a result, make sure to // construct the appropriate return value for our caller. return GetUndefRValue(RetTy); case ABIArgInfo::Extend: case ABIArgInfo::Direct: { llvm::Type *RetIRTy = ConvertType(RetTy); if (RetAI.getCoerceToType() == RetIRTy && RetAI.getDirectOffset() == 0) { switch (getEvaluationKind(RetTy)) { case TEK_Complex: { llvm::Value *Real = Builder.CreateExtractValue(CI, 0); llvm::Value *Imag = Builder.CreateExtractValue(CI, 1); return RValue::getComplex(std::make_pair(Real, Imag)); } case TEK_Aggregate: { llvm::Value *DestPtr = ReturnValue.getValue(); bool DestIsVolatile = ReturnValue.isVolatile(); if (!DestPtr) { DestPtr = CreateMemTemp(RetTy, "agg.tmp"); DestIsVolatile = false; } BuildAggStore(*this, CI, DestPtr, DestIsVolatile, false); return RValue::getAggregate(DestPtr); } case TEK_Scalar: { // If the argument doesn't match, perform a bitcast to coerce it. This // can happen due to trivial type mismatches. llvm::Value *V = CI; if (V->getType() != RetIRTy) V = Builder.CreateBitCast(V, RetIRTy); return RValue::get(V); } } llvm_unreachable("bad evaluation kind"); } llvm::Value *DestPtr = ReturnValue.getValue(); bool DestIsVolatile = ReturnValue.isVolatile(); if (!DestPtr) { DestPtr = CreateMemTemp(RetTy, "coerce"); DestIsVolatile = false; } // If the value is offset in memory, apply the offset now. llvm::Value *StorePtr = DestPtr; if (unsigned Offs = RetAI.getDirectOffset()) { StorePtr = Builder.CreateBitCast(StorePtr, Builder.getInt8PtrTy()); StorePtr = Builder.CreateConstGEP1_32(StorePtr, Offs); StorePtr = Builder.CreateBitCast(StorePtr, llvm::PointerType::getUnqual(RetAI.getCoerceToType())); } CreateCoercedStore(CI, StorePtr, DestIsVolatile, *this); return convertTempToRValue(DestPtr, RetTy); } case ABIArgInfo::Expand: llvm_unreachable("Invalid ABI kind for return argument"); } llvm_unreachable("Unhandled ABIArgInfo::Kind"); } /* VarArg handling */ llvm::Value *CodeGenFunction::EmitVAArg(llvm::Value *VAListAddr, QualType Ty) { return CGM.getTypes().getABIInfo().EmitVAArg(VAListAddr, Ty, *this); }