//===--- CGCall.cpp - Encapsulate calling convention details --------------===// // // 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 "CGCleanup.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/TargetBuiltins.h" #include "clang/Basic/TargetInfo.h" #include "clang/CodeGen/CGFunctionInfo.h" #include "clang/Frontend/CodeGenOptions.h" #include "llvm/ADT/StringExtras.h" #include "llvm/IR/Attributes.h" #include "llvm/IR/CallSite.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/InlineAsm.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/IntrinsicInst.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_X86_64Win64: return llvm::CallingConv::X86_64_Win64; case CC_X86_64SysV: return llvm::CallingConv::X86_64_SysV; 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 __pascal to LLVM. case CC_X86Pascal: return llvm::CallingConv::C; // TODO: Add support for __vectorcall to LLVM. case CC_X86VectorCall: return llvm::CallingConv::X86_VectorCall; case CC_SpirFunction: return llvm::CallingConv::SPIR_FUNC; case CC_SpirKernel: return llvm::CallingConv::SPIR_KERNEL; } } /// 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<FunctionProtoType> GetFormalType(const CXXMethodDecl *MD) { return MD->getType()->getCanonicalTypeUnqualified() .getAs<FunctionProtoType>(); } /// 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<FunctionNoProtoType> FTNP) { // When translating an unprototyped function type, always use a // variadic type. return arrangeLLVMFunctionInfo(FTNP->getReturnType().getUnqualifiedType(), /*instanceMethod=*/false, /*chainCall=*/false, None, FTNP->getExtInfo(), RequiredArgs(0)); } /// Adds the formal paramaters in FPT to the given prefix. If any parameter in /// FPT has pass_object_size attrs, then we'll add parameters for those, too. static void appendParameterTypes(const CodeGenTypes &CGT, SmallVectorImpl<CanQualType> &prefix, const CanQual<FunctionProtoType> &FPT, const FunctionDecl *FD) { // Fast path: unknown target. if (FD == nullptr) { prefix.append(FPT->param_type_begin(), FPT->param_type_end()); return; } // In the vast majority cases, we'll have precisely FPT->getNumParams() // parameters; the only thing that can change this is the presence of // pass_object_size. So, we preallocate for the common case. prefix.reserve(prefix.size() + FPT->getNumParams()); assert(FD->getNumParams() == FPT->getNumParams()); for (unsigned I = 0, E = FPT->getNumParams(); I != E; ++I) { prefix.push_back(FPT->getParamType(I)); if (FD->getParamDecl(I)->hasAttr<PassObjectSizeAttr>()) prefix.push_back(CGT.getContext().getSizeType()); } } /// Arrange the LLVM function layout for a value of the given function /// type, on top of any implicit parameters already stored. static const CGFunctionInfo & arrangeLLVMFunctionInfo(CodeGenTypes &CGT, bool instanceMethod, SmallVectorImpl<CanQualType> &prefix, CanQual<FunctionProtoType> FTP, const FunctionDecl *FD) { RequiredArgs required = RequiredArgs::forPrototypePlus(FTP, prefix.size()); // FIXME: Kill copy. appendParameterTypes(CGT, prefix, FTP, FD); CanQualType resultType = FTP->getReturnType().getUnqualifiedType(); return CGT.arrangeLLVMFunctionInfo(resultType, instanceMethod, /*chainCall=*/false, prefix, FTP->getExtInfo(), required); } /// Arrange the argument and result information for a value of the /// given freestanding function type. const CGFunctionInfo & CodeGenTypes::arrangeFreeFunctionType(CanQual<FunctionProtoType> FTP, const FunctionDecl *FD) { SmallVector<CanQualType, 16> argTypes; return ::arrangeLLVMFunctionInfo(*this, /*instanceMethod=*/false, argTypes, FTP, FD); } static CallingConv getCallingConventionForDecl(const Decl *D, bool IsWindows) { // Set the appropriate calling convention for the Function. if (D->hasAttr<StdCallAttr>()) return CC_X86StdCall; if (D->hasAttr<FastCallAttr>()) return CC_X86FastCall; if (D->hasAttr<ThisCallAttr>()) return CC_X86ThisCall; if (D->hasAttr<VectorCallAttr>()) return CC_X86VectorCall; if (D->hasAttr<PascalAttr>()) return CC_X86Pascal; if (PcsAttr *PCS = D->getAttr<PcsAttr>()) return (PCS->getPCS() == PcsAttr::AAPCS ? CC_AAPCS : CC_AAPCS_VFP); if (D->hasAttr<IntelOclBiccAttr>()) return CC_IntelOclBicc; if (D->hasAttr<MSABIAttr>()) return IsWindows ? CC_C : CC_X86_64Win64; if (D->hasAttr<SysVABIAttr>()) return IsWindows ? CC_X86_64SysV : CC_C; 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. /// (Zero value of RD means we don't have any meaningful "this" argument type, /// so fall back to a generic pointer 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, const CXXMethodDecl *MD) { SmallVector<CanQualType, 16> argTypes; // Add the 'this' pointer. if (RD) argTypes.push_back(GetThisType(Context, RD)); else argTypes.push_back(Context.VoidPtrTy); return ::arrangeLLVMFunctionInfo( *this, true, argTypes, FTP->getCanonicalTypeUnqualified().getAs<FunctionProtoType>(), MD); } /// 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<CXXConstructorDecl>(MD) && "wrong method for constructors!"); assert(!isa<CXXDestructorDecl>(MD) && "wrong method for destructors!"); CanQual<FunctionProtoType> prototype = GetFormalType(MD); if (MD->isInstance()) { // The abstract case is perfectly fine. const CXXRecordDecl *ThisType = TheCXXABI.getThisArgumentTypeForMethod(MD); return arrangeCXXMethodType(ThisType, prototype.getTypePtr(), MD); } return arrangeFreeFunctionType(prototype, MD); } const CGFunctionInfo & CodeGenTypes::arrangeCXXStructorDeclaration(const CXXMethodDecl *MD, StructorType Type) { SmallVector<CanQualType, 16> argTypes; argTypes.push_back(GetThisType(Context, MD->getParent())); GlobalDecl GD; if (auto *CD = dyn_cast<CXXConstructorDecl>(MD)) { GD = GlobalDecl(CD, toCXXCtorType(Type)); } else { auto *DD = dyn_cast<CXXDestructorDecl>(MD); GD = GlobalDecl(DD, toCXXDtorType(Type)); } CanQual<FunctionProtoType> FTP = GetFormalType(MD); // Add the formal parameters. appendParameterTypes(*this, argTypes, FTP, MD); TheCXXABI.buildStructorSignature(MD, Type, argTypes); RequiredArgs required = (MD->isVariadic() ? RequiredArgs(argTypes.size()) : RequiredArgs::All); FunctionType::ExtInfo extInfo = FTP->getExtInfo(); CanQualType resultType = TheCXXABI.HasThisReturn(GD) ? argTypes.front() : TheCXXABI.hasMostDerivedReturn(GD) ? CGM.getContext().VoidPtrTy : Context.VoidTy; return arrangeLLVMFunctionInfo(resultType, /*instanceMethod=*/true, /*chainCall=*/false, argTypes, extInfo, required); } /// Arrange a call to a C++ method, passing the given arguments. const CGFunctionInfo & CodeGenTypes::arrangeCXXConstructorCall(const CallArgList &args, const CXXConstructorDecl *D, CXXCtorType CtorKind, unsigned ExtraArgs) { // FIXME: Kill copy. SmallVector<CanQualType, 16> ArgTypes; for (const auto &Arg : args) ArgTypes.push_back(Context.getCanonicalParamType(Arg.Ty)); CanQual<FunctionProtoType> FPT = GetFormalType(D); RequiredArgs Required = RequiredArgs::forPrototypePlus(FPT, 1 + ExtraArgs); GlobalDecl GD(D, CtorKind); CanQualType ResultType = TheCXXABI.HasThisReturn(GD) ? ArgTypes.front() : TheCXXABI.hasMostDerivedReturn(GD) ? CGM.getContext().VoidPtrTy : Context.VoidTy; FunctionType::ExtInfo Info = FPT->getExtInfo(); return arrangeLLVMFunctionInfo(ResultType, /*instanceMethod=*/true, /*chainCall=*/false, ArgTypes, Info, Required); } /// 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<CXXMethodDecl>(FD)) if (MD->isInstance()) return arrangeCXXMethodDeclaration(MD); CanQualType FTy = FD->getType()->getCanonicalTypeUnqualified(); assert(isa<FunctionType>(FTy)); // When declaring a function without a prototype, always use a // non-variadic type. if (isa<FunctionNoProtoType>(FTy)) { CanQual<FunctionNoProtoType> noProto = FTy.getAs<FunctionNoProtoType>(); return arrangeLLVMFunctionInfo( noProto->getReturnType(), /*instanceMethod=*/false, /*chainCall=*/false, None, noProto->getExtInfo(), RequiredArgs::All); } assert(isa<FunctionProtoType>(FTy)); return arrangeFreeFunctionType(FTy.getAs<FunctionProtoType>(), FD); } /// 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<CanQualType, 16> argTys; argTys.push_back(Context.getCanonicalParamType(receiverType)); argTys.push_back(Context.getCanonicalParamType(Context.getObjCSelType())); // FIXME: Kill copy? for (const auto *I : MD->params()) { argTys.push_back(Context.getCanonicalParamType(I->getType())); } FunctionType::ExtInfo einfo; bool IsWindows = getContext().getTargetInfo().getTriple().isOSWindows(); einfo = einfo.withCallingConv(getCallingConventionForDecl(MD, IsWindows)); if (getContext().getLangOpts().ObjCAutoRefCount && MD->hasAttr<NSReturnsRetainedAttr>()) einfo = einfo.withProducesResult(true); RequiredArgs required = (MD->isVariadic() ? RequiredArgs(argTys.size()) : RequiredArgs::All); return arrangeLLVMFunctionInfo( GetReturnType(MD->getReturnType()), /*instanceMethod=*/false, /*chainCall=*/false, argTys, einfo, required); } const CGFunctionInfo & CodeGenTypes::arrangeGlobalDeclaration(GlobalDecl GD) { // FIXME: Do we need to handle ObjCMethodDecl? const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl()); if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) return arrangeCXXStructorDeclaration(CD, getFromCtorType(GD.getCtorType())); if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) return arrangeCXXStructorDeclaration(DD, getFromDtorType(GD.getDtorType())); return arrangeFunctionDeclaration(FD); } /// Arrange a thunk that takes 'this' as the first parameter followed by /// varargs. Return a void pointer, regardless of the actual return type. /// The body of the thunk will end in a musttail call to a function of the /// correct type, and the caller will bitcast the function to the correct /// prototype. const CGFunctionInfo & CodeGenTypes::arrangeMSMemberPointerThunk(const CXXMethodDecl *MD) { assert(MD->isVirtual() && "only virtual memptrs have thunks"); CanQual<FunctionProtoType> FTP = GetFormalType(MD); CanQualType ArgTys[] = { GetThisType(Context, MD->getParent()) }; return arrangeLLVMFunctionInfo(Context.VoidTy, /*instanceMethod=*/false, /*chainCall=*/false, ArgTys, FTP->getExtInfo(), RequiredArgs(1)); } const CGFunctionInfo & CodeGenTypes::arrangeMSCtorClosure(const CXXConstructorDecl *CD, CXXCtorType CT) { assert(CT == Ctor_CopyingClosure || CT == Ctor_DefaultClosure); CanQual<FunctionProtoType> FTP = GetFormalType(CD); SmallVector<CanQualType, 2> ArgTys; const CXXRecordDecl *RD = CD->getParent(); ArgTys.push_back(GetThisType(Context, RD)); if (CT == Ctor_CopyingClosure) ArgTys.push_back(*FTP->param_type_begin()); if (RD->getNumVBases() > 0) ArgTys.push_back(Context.IntTy); CallingConv CC = Context.getDefaultCallingConvention( /*IsVariadic=*/false, /*IsCXXMethod=*/true); return arrangeLLVMFunctionInfo(Context.VoidTy, /*instanceMethod=*/true, /*chainCall=*/false, ArgTys, FunctionType::ExtInfo(CC), RequiredArgs::All); } /// 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, CodeGenModule &CGM, const CallArgList &args, const FunctionType *fnType, unsigned numExtraRequiredArgs, bool chainCall) { 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<FunctionProtoType>(fnType)) { if (proto->isVariadic()) required = RequiredArgs(proto->getNumParams() + 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 (CGM.getTargetCodeGenInfo() .isNoProtoCallVariadic(args, cast<FunctionNoProtoType>(fnType))) { required = RequiredArgs(args.size()); } // FIXME: Kill copy. SmallVector<CanQualType, 16> argTypes; for (const auto &arg : args) argTypes.push_back(CGT.getContext().getCanonicalParamType(arg.Ty)); return CGT.arrangeLLVMFunctionInfo(GetReturnType(fnType->getReturnType()), /*instanceMethod=*/false, chainCall, argTypes, 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, bool chainCall) { return arrangeFreeFunctionLikeCall(*this, CGM, args, fnType, chainCall ? 1 : 0, chainCall); } /// 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, CGM, args, fnType, 1, /*chainCall=*/false); } const CGFunctionInfo & CodeGenTypes::arrangeFreeFunctionCall(QualType resultType, const CallArgList &args, FunctionType::ExtInfo info, RequiredArgs required) { // FIXME: Kill copy. SmallVector<CanQualType, 16> argTypes; for (const auto &Arg : args) argTypes.push_back(Context.getCanonicalParamType(Arg.Ty)); return arrangeLLVMFunctionInfo( GetReturnType(resultType), /*instanceMethod=*/false, /*chainCall=*/false, 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<CanQualType, 16> argTypes; for (const auto &Arg : args) argTypes.push_back(Context.getCanonicalParamType(Arg.Ty)); FunctionType::ExtInfo info = FPT->getExtInfo(); return arrangeLLVMFunctionInfo( GetReturnType(FPT->getReturnType()), /*instanceMethod=*/true, /*chainCall=*/false, argTypes, info, required); } const CGFunctionInfo &CodeGenTypes::arrangeFreeFunctionDeclaration( QualType resultType, const FunctionArgList &args, const FunctionType::ExtInfo &info, bool isVariadic) { // FIXME: Kill copy. SmallVector<CanQualType, 16> argTypes; for (auto Arg : args) argTypes.push_back(Context.getCanonicalParamType(Arg->getType())); RequiredArgs required = (isVariadic ? RequiredArgs(args.size()) : RequiredArgs::All); return arrangeLLVMFunctionInfo( GetReturnType(resultType), /*instanceMethod=*/false, /*chainCall=*/false, argTypes, info, required); } const CGFunctionInfo &CodeGenTypes::arrangeNullaryFunction() { return arrangeLLVMFunctionInfo( getContext().VoidTy, /*instanceMethod=*/false, /*chainCall=*/false, 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, bool instanceMethod, bool chainCall, ArrayRef<CanQualType> argTypes, FunctionType::ExtInfo info, RequiredArgs required) { assert(std::all_of(argTypes.begin(), argTypes.end(), std::mem_fun_ref(&CanQualType::isCanonicalAsParam))); unsigned CC = ClangCallConvToLLVMCallConv(info.getCC()); // Lookup or create unique function info. llvm::FoldingSetNodeID ID; CGFunctionInfo::Profile(ID, instanceMethod, chainCall, info, required, resultType, argTypes); void *insertPos = nullptr; CGFunctionInfo *FI = FunctionInfos.FindNodeOrInsertPos(ID, insertPos); if (FI) return *FI; // Construct the function info. We co-allocate the ArgInfos. FI = CGFunctionInfo::create(CC, instanceMethod, chainCall, info, resultType, argTypes, required); FunctionInfos.InsertNode(FI, insertPos); bool inserted = FunctionsBeingProcessed.insert(FI).second; (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() == nullptr) retInfo.setCoerceToType(ConvertType(FI->getReturnType())); for (auto &I : FI->arguments()) if (I.info.canHaveCoerceToType() && I.info.getCoerceToType() == nullptr) 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, bool instanceMethod, bool chainCall, const FunctionType::ExtInfo &info, CanQualType resultType, ArrayRef<CanQualType> 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->InstanceMethod = instanceMethod; FI->ChainCall = chainCall; FI->NoReturn = info.getNoReturn(); FI->ReturnsRetained = info.getProducesResult(); FI->Required = required; FI->HasRegParm = info.getHasRegParm(); FI->RegParm = info.getRegParm(); FI->ArgStruct = nullptr; FI->ArgStructAlign = 0; 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; } /***/ namespace { // ABIArgInfo::Expand implementation. // Specifies the way QualType passed as ABIArgInfo::Expand is expanded. struct TypeExpansion { enum TypeExpansionKind { // Elements of constant arrays are expanded recursively. TEK_ConstantArray, // Record fields are expanded recursively (but if record is a union, only // the field with the largest size is expanded). TEK_Record, // For complex types, real and imaginary parts are expanded recursively. TEK_Complex, // All other types are not expandable. TEK_None }; const TypeExpansionKind Kind; TypeExpansion(TypeExpansionKind K) : Kind(K) {} virtual ~TypeExpansion() {} }; struct ConstantArrayExpansion : TypeExpansion { QualType EltTy; uint64_t NumElts; ConstantArrayExpansion(QualType EltTy, uint64_t NumElts) : TypeExpansion(TEK_ConstantArray), EltTy(EltTy), NumElts(NumElts) {} static bool classof(const TypeExpansion *TE) { return TE->Kind == TEK_ConstantArray; } }; struct RecordExpansion : TypeExpansion { SmallVector<const CXXBaseSpecifier *, 1> Bases; SmallVector<const FieldDecl *, 1> Fields; RecordExpansion(SmallVector<const CXXBaseSpecifier *, 1> &&Bases, SmallVector<const FieldDecl *, 1> &&Fields) : TypeExpansion(TEK_Record), Bases(Bases), Fields(Fields) {} static bool classof(const TypeExpansion *TE) { return TE->Kind == TEK_Record; } }; struct ComplexExpansion : TypeExpansion { QualType EltTy; ComplexExpansion(QualType EltTy) : TypeExpansion(TEK_Complex), EltTy(EltTy) {} static bool classof(const TypeExpansion *TE) { return TE->Kind == TEK_Complex; } }; struct NoExpansion : TypeExpansion { NoExpansion() : TypeExpansion(TEK_None) {} static bool classof(const TypeExpansion *TE) { return TE->Kind == TEK_None; } }; } // namespace static std::unique_ptr<TypeExpansion> getTypeExpansion(QualType Ty, const ASTContext &Context) { if (const ConstantArrayType *AT = Context.getAsConstantArrayType(Ty)) { return llvm::make_unique<ConstantArrayExpansion>( AT->getElementType(), AT->getSize().getZExtValue()); } if (const RecordType *RT = Ty->getAs<RecordType>()) { SmallVector<const CXXBaseSpecifier *, 1> Bases; SmallVector<const FieldDecl *, 1> Fields; 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 = nullptr; CharUnits UnionSize = CharUnits::Zero(); for (const auto *FD : RD->fields()) { // Skip zero length bitfields. if (FD->isBitField() && FD->getBitWidthValue(Context) == 0) continue; assert(!FD->isBitField() && "Cannot expand structure with bit-field members."); CharUnits FieldSize = Context.getTypeSizeInChars(FD->getType()); if (UnionSize < FieldSize) { UnionSize = FieldSize; LargestFD = FD; } } if (LargestFD) Fields.push_back(LargestFD); } else { if (const auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) { assert(!CXXRD->isDynamicClass() && "cannot expand vtable pointers in dynamic classes"); for (const CXXBaseSpecifier &BS : CXXRD->bases()) Bases.push_back(&BS); } for (const auto *FD : RD->fields()) { // Skip zero length bitfields. if (FD->isBitField() && FD->getBitWidthValue(Context) == 0) continue; assert(!FD->isBitField() && "Cannot expand structure with bit-field members."); Fields.push_back(FD); } } return llvm::make_unique<RecordExpansion>(std::move(Bases), std::move(Fields)); } if (const ComplexType *CT = Ty->getAs<ComplexType>()) { return llvm::make_unique<ComplexExpansion>(CT->getElementType()); } return llvm::make_unique<NoExpansion>(); } static int getExpansionSize(QualType Ty, const ASTContext &Context) { auto Exp = getTypeExpansion(Ty, Context); if (auto CAExp = dyn_cast<ConstantArrayExpansion>(Exp.get())) { return CAExp->NumElts * getExpansionSize(CAExp->EltTy, Context); } if (auto RExp = dyn_cast<RecordExpansion>(Exp.get())) { int Res = 0; for (auto BS : RExp->Bases) Res += getExpansionSize(BS->getType(), Context); for (auto FD : RExp->Fields) Res += getExpansionSize(FD->getType(), Context); return Res; } if (isa<ComplexExpansion>(Exp.get())) return 2; assert(isa<NoExpansion>(Exp.get())); return 1; } void CodeGenTypes::getExpandedTypes(QualType Ty, SmallVectorImpl<llvm::Type *>::iterator &TI) { auto Exp = getTypeExpansion(Ty, Context); if (auto CAExp = dyn_cast<ConstantArrayExpansion>(Exp.get())) { for (int i = 0, n = CAExp->NumElts; i < n; i++) { getExpandedTypes(CAExp->EltTy, TI); } } else if (auto RExp = dyn_cast<RecordExpansion>(Exp.get())) { for (auto BS : RExp->Bases) getExpandedTypes(BS->getType(), TI); for (auto FD : RExp->Fields) getExpandedTypes(FD->getType(), TI); } else if (auto CExp = dyn_cast<ComplexExpansion>(Exp.get())) { llvm::Type *EltTy = ConvertType(CExp->EltTy); *TI++ = EltTy; *TI++ = EltTy; } else { assert(isa<NoExpansion>(Exp.get())); *TI++ = ConvertType(Ty); } } static void forConstantArrayExpansion(CodeGenFunction &CGF, ConstantArrayExpansion *CAE, Address BaseAddr, llvm::function_ref<void(Address)> Fn) { CharUnits EltSize = CGF.getContext().getTypeSizeInChars(CAE->EltTy); CharUnits EltAlign = BaseAddr.getAlignment().alignmentOfArrayElement(EltSize); for (int i = 0, n = CAE->NumElts; i < n; i++) { llvm::Value *EltAddr = CGF.Builder.CreateConstGEP2_32(nullptr, BaseAddr.getPointer(), 0, i); Fn(Address(EltAddr, EltAlign)); } } void CodeGenFunction::ExpandTypeFromArgs( QualType Ty, LValue LV, SmallVectorImpl<llvm::Argument *>::iterator &AI) { assert(LV.isSimple() && "Unexpected non-simple lvalue during struct expansion."); auto Exp = getTypeExpansion(Ty, getContext()); if (auto CAExp = dyn_cast<ConstantArrayExpansion>(Exp.get())) { forConstantArrayExpansion(*this, CAExp, LV.getAddress(), [&](Address EltAddr) { LValue LV = MakeAddrLValue(EltAddr, CAExp->EltTy); ExpandTypeFromArgs(CAExp->EltTy, LV, AI); }); } else if (auto RExp = dyn_cast<RecordExpansion>(Exp.get())) { Address This = LV.getAddress(); for (const CXXBaseSpecifier *BS : RExp->Bases) { // Perform a single step derived-to-base conversion. Address Base = GetAddressOfBaseClass(This, Ty->getAsCXXRecordDecl(), &BS, &BS + 1, /*NullCheckValue=*/false, SourceLocation()); LValue SubLV = MakeAddrLValue(Base, BS->getType()); // Recurse onto bases. ExpandTypeFromArgs(BS->getType(), SubLV, AI); } for (auto FD : RExp->Fields) { // FIXME: What are the right qualifiers here? LValue SubLV = EmitLValueForField(LV, FD); ExpandTypeFromArgs(FD->getType(), SubLV, AI); } } else if (isa<ComplexExpansion>(Exp.get())) { auto realValue = *AI++; auto imagValue = *AI++; EmitStoreOfComplex(ComplexPairTy(realValue, imagValue), LV, /*init*/ true); } else { assert(isa<NoExpansion>(Exp.get())); EmitStoreThroughLValue(RValue::get(*AI++), LV); } } void CodeGenFunction::ExpandTypeToArgs( QualType Ty, RValue RV, llvm::FunctionType *IRFuncTy, SmallVectorImpl<llvm::Value *> &IRCallArgs, unsigned &IRCallArgPos) { auto Exp = getTypeExpansion(Ty, getContext()); if (auto CAExp = dyn_cast<ConstantArrayExpansion>(Exp.get())) { forConstantArrayExpansion(*this, CAExp, RV.getAggregateAddress(), [&](Address EltAddr) { RValue EltRV = convertTempToRValue(EltAddr, CAExp->EltTy, SourceLocation()); ExpandTypeToArgs(CAExp->EltTy, EltRV, IRFuncTy, IRCallArgs, IRCallArgPos); }); } else if (auto RExp = dyn_cast<RecordExpansion>(Exp.get())) { Address This = RV.getAggregateAddress(); for (const CXXBaseSpecifier *BS : RExp->Bases) { // Perform a single step derived-to-base conversion. Address Base = GetAddressOfBaseClass(This, Ty->getAsCXXRecordDecl(), &BS, &BS + 1, /*NullCheckValue=*/false, SourceLocation()); RValue BaseRV = RValue::getAggregate(Base); // Recurse onto bases. ExpandTypeToArgs(BS->getType(), BaseRV, IRFuncTy, IRCallArgs, IRCallArgPos); } LValue LV = MakeAddrLValue(This, Ty); for (auto FD : RExp->Fields) { RValue FldRV = EmitRValueForField(LV, FD, SourceLocation()); ExpandTypeToArgs(FD->getType(), FldRV, IRFuncTy, IRCallArgs, IRCallArgPos); } } else if (isa<ComplexExpansion>(Exp.get())) { ComplexPairTy CV = RV.getComplexVal(); IRCallArgs[IRCallArgPos++] = CV.first; IRCallArgs[IRCallArgPos++] = CV.second; } else { assert(isa<NoExpansion>(Exp.get())); assert(RV.isScalar() && "Unexpected non-scalar rvalue during struct expansion."); // Insert a bitcast as needed. llvm::Value *V = RV.getScalarVal(); if (IRCallArgPos < IRFuncTy->getNumParams() && V->getType() != IRFuncTy->getParamType(IRCallArgPos)) V = Builder.CreateBitCast(V, IRFuncTy->getParamType(IRCallArgPos)); IRCallArgs[IRCallArgPos++] = V; } } /// Create a temporary allocation for the purposes of coercion. static Address CreateTempAllocaForCoercion(CodeGenFunction &CGF, llvm::Type *Ty, CharUnits MinAlign) { // Don't use an alignment that's worse than what LLVM would prefer. auto PrefAlign = CGF.CGM.getDataLayout().getPrefTypeAlignment(Ty); CharUnits Align = std::max(MinAlign, CharUnits::fromQuantity(PrefAlign)); return CGF.CreateTempAlloca(Ty, Align); } /// 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 Address EnterStructPointerForCoercedAccess(Address 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. The // comparison must be made on the store size and not the alloca size. Using // the alloca size may overstate the size of the load. uint64_t FirstEltSize = CGF.CGM.getDataLayout().getTypeStoreSize(FirstElt); if (FirstEltSize < DstSize && FirstEltSize < CGF.CGM.getDataLayout().getTypeStoreSize(SrcSTy)) return SrcPtr; // GEP into the first element. SrcPtr = CGF.Builder.CreateStructGEP(SrcPtr, 0, CharUnits(), "coerce.dive"); // If the first element is a struct, recurse. llvm::Type *SrcTy = SrcPtr.getElementType(); if (llvm::StructType *SrcSTy = dyn_cast<llvm::StructType>(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. /// /// This behaves as if the value were coerced through memory, so on big-endian /// targets the high bits are preserved in a truncation, while little-endian /// targets preserve the low bits. static llvm::Value *CoerceIntOrPtrToIntOrPtr(llvm::Value *Val, llvm::Type *Ty, CodeGenFunction &CGF) { if (Val->getType() == Ty) return Val; if (isa<llvm::PointerType>(Val->getType())) { // If this is Pointer->Pointer avoid conversion to and from int. if (isa<llvm::PointerType>(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<llvm::PointerType>(DestIntTy)) DestIntTy = CGF.IntPtrTy; if (Val->getType() != DestIntTy) { const llvm::DataLayout &DL = CGF.CGM.getDataLayout(); if (DL.isBigEndian()) { // Preserve the high bits on big-endian targets. // That is what memory coercion does. uint64_t SrcSize = DL.getTypeSizeInBits(Val->getType()); uint64_t DstSize = DL.getTypeSizeInBits(DestIntTy); if (SrcSize > DstSize) { Val = CGF.Builder.CreateLShr(Val, SrcSize - DstSize, "coerce.highbits"); Val = CGF.Builder.CreateTrunc(Val, DestIntTy, "coerce.val.ii"); } else { Val = CGF.Builder.CreateZExt(Val, DestIntTy, "coerce.val.ii"); Val = CGF.Builder.CreateShl(Val, DstSize - SrcSize, "coerce.highbits"); } } else { // Little-endian targets preserve the low bits. No shifts required. Val = CGF.Builder.CreateIntCast(Val, DestIntTy, false, "coerce.val.ii"); } } if (isa<llvm::PointerType>(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, known to be aligned to /// \arg SrcAlign bytes. /// /// 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(Address Src, llvm::Type *Ty, CodeGenFunction &CGF) { llvm::Type *SrcTy = Src.getElementType(); // If SrcTy and Ty are the same, just do a load. if (SrcTy == Ty) return CGF.Builder.CreateLoad(Src); uint64_t DstSize = CGF.CGM.getDataLayout().getTypeAllocSize(Ty); if (llvm::StructType *SrcSTy = dyn_cast<llvm::StructType>(SrcTy)) { Src = EnterStructPointerForCoercedAccess(Src, SrcSTy, DstSize, CGF); SrcTy = Src.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<llvm::IntegerType>(Ty) || isa<llvm::PointerType>(Ty)) && (isa<llvm::IntegerType>(SrcTy) || isa<llvm::PointerType>(SrcTy))) { llvm::Value *Load = CGF.Builder.CreateLoad(Src); 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. Src = CGF.Builder.CreateBitCast(Src, llvm::PointerType::getUnqual(Ty)); return CGF.Builder.CreateLoad(Src); } // Otherwise do coercion through memory. This is stupid, but simple. Address Tmp = CreateTempAllocaForCoercion(CGF, Ty, Src.getAlignment()); Address Casted = CGF.Builder.CreateBitCast(Tmp, CGF.Int8PtrTy); Address SrcCasted = CGF.Builder.CreateBitCast(Src, CGF.Int8PtrTy); CGF.Builder.CreateMemCpy(Casted, SrcCasted, llvm::ConstantInt::get(CGF.IntPtrTy, SrcSize), 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, Address Dest, bool DestIsVolatile) { // Prefer scalar stores to first-class aggregate stores. if (llvm::StructType *STy = dyn_cast<llvm::StructType>(Val->getType())) { const llvm::StructLayout *Layout = CGF.CGM.getDataLayout().getStructLayout(STy); for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { auto EltOffset = CharUnits::fromQuantity(Layout->getElementOffset(i)); Address EltPtr = CGF.Builder.CreateStructGEP(Dest, i, EltOffset); llvm::Value *Elt = CGF.Builder.CreateExtractValue(Val, i); CGF.Builder.CreateStore(Elt, EltPtr, DestIsVolatile); } } else { CGF.Builder.CreateStore(Val, Dest, DestIsVolatile); } } /// CreateCoercedStore - Create a store to \arg DstPtr from \arg Src, /// where the source and destination may have different types. The /// destination is known to be aligned to \arg DstAlign bytes. /// /// 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, Address Dst, bool DstIsVolatile, CodeGenFunction &CGF) { llvm::Type *SrcTy = Src->getType(); llvm::Type *DstTy = Dst.getType()->getElementType(); if (SrcTy == DstTy) { CGF.Builder.CreateStore(Src, Dst, DstIsVolatile); return; } uint64_t SrcSize = CGF.CGM.getDataLayout().getTypeAllocSize(SrcTy); if (llvm::StructType *DstSTy = dyn_cast<llvm::StructType>(DstTy)) { Dst = EnterStructPointerForCoercedAccess(Dst, DstSTy, SrcSize, CGF); DstTy = Dst.getType()->getElementType(); } // If the source and destination are integer or pointer types, just do an // extension or truncation to the desired type. if ((isa<llvm::IntegerType>(SrcTy) || isa<llvm::PointerType>(SrcTy)) && (isa<llvm::IntegerType>(DstTy) || isa<llvm::PointerType>(DstTy))) { Src = CoerceIntOrPtrToIntOrPtr(Src, DstTy, CGF); CGF.Builder.CreateStore(Src, Dst, DstIsVolatile); return; } uint64_t DstSize = CGF.CGM.getDataLayout().getTypeAllocSize(DstTy); // If store is legal, just bitcast the src pointer. if (SrcSize <= DstSize) { Dst = CGF.Builder.CreateBitCast(Dst, llvm::PointerType::getUnqual(SrcTy)); BuildAggStore(CGF, Src, Dst, DstIsVolatile); } 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. Address Tmp = CreateTempAllocaForCoercion(CGF, SrcTy, Dst.getAlignment()); CGF.Builder.CreateStore(Src, Tmp); Address Casted = CGF.Builder.CreateBitCast(Tmp, CGF.Int8PtrTy); Address DstCasted = CGF.Builder.CreateBitCast(Dst, CGF.Int8PtrTy); CGF.Builder.CreateMemCpy(DstCasted, Casted, llvm::ConstantInt::get(CGF.IntPtrTy, DstSize), false); } } static Address emitAddressAtOffset(CodeGenFunction &CGF, Address addr, const ABIArgInfo &info) { if (unsigned offset = info.getDirectOffset()) { addr = CGF.Builder.CreateElementBitCast(addr, CGF.Int8Ty); addr = CGF.Builder.CreateConstInBoundsByteGEP(addr, CharUnits::fromQuantity(offset)); addr = CGF.Builder.CreateElementBitCast(addr, info.getCoerceToType()); } return addr; } namespace { /// Encapsulates information about the way function arguments from /// CGFunctionInfo should be passed to actual LLVM IR function. class ClangToLLVMArgMapping { static const unsigned InvalidIndex = ~0U; unsigned InallocaArgNo; unsigned SRetArgNo; unsigned TotalIRArgs; /// Arguments of LLVM IR function corresponding to single Clang argument. struct IRArgs { unsigned PaddingArgIndex; // Argument is expanded to IR arguments at positions // [FirstArgIndex, FirstArgIndex + NumberOfArgs). unsigned FirstArgIndex; unsigned NumberOfArgs; IRArgs() : PaddingArgIndex(InvalidIndex), FirstArgIndex(InvalidIndex), NumberOfArgs(0) {} }; SmallVector<IRArgs, 8> ArgInfo; public: ClangToLLVMArgMapping(const ASTContext &Context, const CGFunctionInfo &FI, bool OnlyRequiredArgs = false) : InallocaArgNo(InvalidIndex), SRetArgNo(InvalidIndex), TotalIRArgs(0), ArgInfo(OnlyRequiredArgs ? FI.getNumRequiredArgs() : FI.arg_size()) { construct(Context, FI, OnlyRequiredArgs); } bool hasInallocaArg() const { return InallocaArgNo != InvalidIndex; } unsigned getInallocaArgNo() const { assert(hasInallocaArg()); return InallocaArgNo; } bool hasSRetArg() const { return SRetArgNo != InvalidIndex; } unsigned getSRetArgNo() const { assert(hasSRetArg()); return SRetArgNo; } unsigned totalIRArgs() const { return TotalIRArgs; } bool hasPaddingArg(unsigned ArgNo) const { assert(ArgNo < ArgInfo.size()); return ArgInfo[ArgNo].PaddingArgIndex != InvalidIndex; } unsigned getPaddingArgNo(unsigned ArgNo) const { assert(hasPaddingArg(ArgNo)); return ArgInfo[ArgNo].PaddingArgIndex; } /// Returns index of first IR argument corresponding to ArgNo, and their /// quantity. std::pair<unsigned, unsigned> getIRArgs(unsigned ArgNo) const { assert(ArgNo < ArgInfo.size()); return std::make_pair(ArgInfo[ArgNo].FirstArgIndex, ArgInfo[ArgNo].NumberOfArgs); } private: void construct(const ASTContext &Context, const CGFunctionInfo &FI, bool OnlyRequiredArgs); }; void ClangToLLVMArgMapping::construct(const ASTContext &Context, const CGFunctionInfo &FI, bool OnlyRequiredArgs) { unsigned IRArgNo = 0; bool SwapThisWithSRet = false; const ABIArgInfo &RetAI = FI.getReturnInfo(); if (RetAI.getKind() == ABIArgInfo::Indirect) { SwapThisWithSRet = RetAI.isSRetAfterThis(); SRetArgNo = SwapThisWithSRet ? 1 : IRArgNo++; } unsigned ArgNo = 0; unsigned NumArgs = OnlyRequiredArgs ? FI.getNumRequiredArgs() : FI.arg_size(); for (CGFunctionInfo::const_arg_iterator I = FI.arg_begin(); ArgNo < NumArgs; ++I, ++ArgNo) { assert(I != FI.arg_end()); QualType ArgType = I->type; const ABIArgInfo &AI = I->info; // Collect data about IR arguments corresponding to Clang argument ArgNo. auto &IRArgs = ArgInfo[ArgNo]; if (AI.getPaddingType()) IRArgs.PaddingArgIndex = IRArgNo++; switch (AI.getKind()) { case ABIArgInfo::Extend: case ABIArgInfo::Direct: { // FIXME: handle sseregparm someday... llvm::StructType *STy = dyn_cast<llvm::StructType>(AI.getCoerceToType()); if (AI.isDirect() && AI.getCanBeFlattened() && STy) { IRArgs.NumberOfArgs = STy->getNumElements(); } else { IRArgs.NumberOfArgs = 1; } break; } case ABIArgInfo::Indirect: IRArgs.NumberOfArgs = 1; break; case ABIArgInfo::Ignore: case ABIArgInfo::InAlloca: // ignore and inalloca doesn't have matching LLVM parameters. IRArgs.NumberOfArgs = 0; break; case ABIArgInfo::Expand: { IRArgs.NumberOfArgs = getExpansionSize(ArgType, Context); break; } } if (IRArgs.NumberOfArgs > 0) { IRArgs.FirstArgIndex = IRArgNo; IRArgNo += IRArgs.NumberOfArgs; } // Skip over the sret parameter when it comes second. We already handled it // above. if (IRArgNo == 1 && SwapThisWithSRet) IRArgNo++; } assert(ArgNo == ArgInfo.size()); if (FI.usesInAlloca()) InallocaArgNo = IRArgNo++; TotalIRArgs = IRArgNo; } } // namespace /***/ bool CodeGenModule::ReturnTypeUsesSRet(const CGFunctionInfo &FI) { return FI.getReturnInfo().isIndirect(); } bool CodeGenModule::ReturnSlotInterferesWithArgs(const CGFunctionInfo &FI) { return ReturnTypeUsesSRet(FI) && getTargetCodeGenInfo().doesReturnSlotInterfereWithArgs(); } bool CodeGenModule::ReturnTypeUsesFPRet(QualType ResultType) { if (const BuiltinType *BT = ResultType->getAs<BuiltinType>()) { 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<ComplexType>()) { if (const BuiltinType *BT = CT->getElementType()->getAs<BuiltinType>()) { 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).second; (void)Inserted; assert(Inserted && "Recursively being processed?"); llvm::Type *resultType = nullptr; 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::InAlloca: if (retAI.getInAllocaSRet()) { // sret things on win32 aren't void, they return the sret pointer. QualType ret = FI.getReturnType(); llvm::Type *ty = ConvertType(ret); unsigned addressSpace = Context.getTargetAddressSpace(ret); resultType = llvm::PointerType::get(ty, addressSpace); } else { resultType = llvm::Type::getVoidTy(getLLVMContext()); } break; case ABIArgInfo::Indirect: case ABIArgInfo::Ignore: resultType = llvm::Type::getVoidTy(getLLVMContext()); break; } ClangToLLVMArgMapping IRFunctionArgs(getContext(), FI, true); SmallVector<llvm::Type*, 8> ArgTypes(IRFunctionArgs.totalIRArgs()); // Add type for sret argument. if (IRFunctionArgs.hasSRetArg()) { QualType Ret = FI.getReturnType(); llvm::Type *Ty = ConvertType(Ret); unsigned AddressSpace = Context.getTargetAddressSpace(Ret); ArgTypes[IRFunctionArgs.getSRetArgNo()] = llvm::PointerType::get(Ty, AddressSpace); } // Add type for inalloca argument. if (IRFunctionArgs.hasInallocaArg()) { auto ArgStruct = FI.getArgStruct(); assert(ArgStruct); ArgTypes[IRFunctionArgs.getInallocaArgNo()] = ArgStruct->getPointerTo(); } // Add in all of the required arguments. unsigned ArgNo = 0; CGFunctionInfo::const_arg_iterator it = FI.arg_begin(), ie = it + FI.getNumRequiredArgs(); for (; it != ie; ++it, ++ArgNo) { const ABIArgInfo &ArgInfo = it->info; // Insert a padding type to ensure proper alignment. if (IRFunctionArgs.hasPaddingArg(ArgNo)) ArgTypes[IRFunctionArgs.getPaddingArgNo(ArgNo)] = ArgInfo.getPaddingType(); unsigned FirstIRArg, NumIRArgs; std::tie(FirstIRArg, NumIRArgs) = IRFunctionArgs.getIRArgs(ArgNo); switch (ArgInfo.getKind()) { case ABIArgInfo::Ignore: case ABIArgInfo::InAlloca: assert(NumIRArgs == 0); break; case ABIArgInfo::Indirect: { assert(NumIRArgs == 1); // indirect arguments are always on the stack, which is addr space #0. llvm::Type *LTy = ConvertTypeForMem(it->type); ArgTypes[FirstIRArg] = LTy->getPointerTo(); break; } case ABIArgInfo::Extend: case ABIArgInfo::Direct: { // Fast-isel and the optimizer generally like scalar values better than // FCAs, so we flatten them if this is safe to do for this argument. llvm::Type *argType = ArgInfo.getCoerceToType(); llvm::StructType *st = dyn_cast<llvm::StructType>(argType); if (st && ArgInfo.isDirect() && ArgInfo.getCanBeFlattened()) { assert(NumIRArgs == st->getNumElements()); for (unsigned i = 0, e = st->getNumElements(); i != e; ++i) ArgTypes[FirstIRArg + i] = st->getElementType(i); } else { assert(NumIRArgs == 1); ArgTypes[FirstIRArg] = argType; } break; } case ABIArgInfo::Expand: auto ArgTypesIter = ArgTypes.begin() + FirstIRArg; getExpandedTypes(it->type, ArgTypesIter); assert(ArgTypesIter == ArgTypes.begin() + FirstIRArg + NumIRArgs); 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<CXXMethodDecl>(GD.getDecl()); const FunctionProtoType *FPT = MD->getType()->getAs<FunctionProtoType>(); if (!isFuncTypeConvertible(FPT)) return llvm::StructType::get(getLLVMContext()); const CGFunctionInfo *Info; if (isa<CXXDestructorDecl>(MD)) Info = &arrangeCXXStructorDeclaration(MD, getFromDtorType(GD.getDtorType())); else Info = &arrangeCXXMethodDeclaration(MD); return GetFunctionType(*Info); } static void AddAttributesFromFunctionProtoType(ASTContext &Ctx, llvm::AttrBuilder &FuncAttrs, const FunctionProtoType *FPT) { if (!FPT) return; if (!isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) && FPT->isNothrow(Ctx)) FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); } void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI, CGCalleeInfo CalleeInfo, AttributeListType &PAL, unsigned &CallingConv, bool AttrOnCallSite) { llvm::AttrBuilder FuncAttrs; llvm::AttrBuilder RetAttrs; bool HasOptnone = false; CallingConv = FI.getEffectiveCallingConvention(); if (FI.isNoReturn()) FuncAttrs.addAttribute(llvm::Attribute::NoReturn); // If we have information about the function prototype, we can learn // attributes form there. AddAttributesFromFunctionProtoType(getContext(), FuncAttrs, CalleeInfo.getCalleeFunctionProtoType()); const Decl *TargetDecl = CalleeInfo.getCalleeDecl(); // FIXME: handle sseregparm someday... if (TargetDecl) { if (TargetDecl->hasAttr<ReturnsTwiceAttr>()) FuncAttrs.addAttribute(llvm::Attribute::ReturnsTwice); if (TargetDecl->hasAttr<NoThrowAttr>()) FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); if (TargetDecl->hasAttr<NoReturnAttr>()) FuncAttrs.addAttribute(llvm::Attribute::NoReturn); if (TargetDecl->hasAttr<NoDuplicateAttr>()) FuncAttrs.addAttribute(llvm::Attribute::NoDuplicate); if (const FunctionDecl *Fn = dyn_cast<FunctionDecl>(TargetDecl)) { AddAttributesFromFunctionProtoType( getContext(), FuncAttrs, Fn->getType()->getAs<FunctionProtoType>()); // 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<CXXMethodDecl>(Fn); if (Fn->isNoReturn() && !(AttrOnCallSite && MD && MD->isVirtual())) FuncAttrs.addAttribute(llvm::Attribute::NoReturn); } // 'const', 'pure' and 'noalias' attributed functions are also nounwind. if (TargetDecl->hasAttr<ConstAttr>()) { FuncAttrs.addAttribute(llvm::Attribute::ReadNone); FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); } else if (TargetDecl->hasAttr<PureAttr>()) { FuncAttrs.addAttribute(llvm::Attribute::ReadOnly); FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); } else if (TargetDecl->hasAttr<NoAliasAttr>()) { FuncAttrs.addAttribute(llvm::Attribute::ArgMemOnly); FuncAttrs.addAttribute(llvm::Attribute::NoUnwind); } if (TargetDecl->hasAttr<RestrictAttr>()) RetAttrs.addAttribute(llvm::Attribute::NoAlias); if (TargetDecl->hasAttr<ReturnsNonNullAttr>()) RetAttrs.addAttribute(llvm::Attribute::NonNull); HasOptnone = TargetDecl->hasAttr<OptimizeNoneAttr>(); } // OptimizeNoneAttr takes precedence over -Os or -Oz. No warning needed. if (!HasOptnone) { 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 (CodeGenOpts.EnableSegmentedStacks && !(TargetDecl && TargetDecl->hasAttr<NoSplitStackAttr>())) FuncAttrs.addAttribute("split-stack"); if (AttrOnCallSite) { // Attributes that should go on the call site only. if (!CodeGenOpts.SimplifyLibCalls) FuncAttrs.addAttribute(llvm::Attribute::NoBuiltin); if (!CodeGenOpts.TrapFuncName.empty()) FuncAttrs.addAttribute("trap-func-name", CodeGenOpts.TrapFuncName); } else { // Attributes that should go on the function, but not the call site. if (!CodeGenOpts.DisableFPElim) { FuncAttrs.addAttribute("no-frame-pointer-elim", "false"); } else if (CodeGenOpts.OmitLeafFramePointer) { FuncAttrs.addAttribute("no-frame-pointer-elim", "false"); FuncAttrs.addAttribute("no-frame-pointer-elim-non-leaf"); } else { FuncAttrs.addAttribute("no-frame-pointer-elim", "true"); FuncAttrs.addAttribute("no-frame-pointer-elim-non-leaf"); } bool DisableTailCalls = CodeGenOpts.DisableTailCalls || (TargetDecl && TargetDecl->hasAttr<DisableTailCallsAttr>()); FuncAttrs.addAttribute("disable-tail-calls", llvm::toStringRef(DisableTailCalls)); FuncAttrs.addAttribute("less-precise-fpmad", llvm::toStringRef(CodeGenOpts.LessPreciseFPMAD)); FuncAttrs.addAttribute("no-infs-fp-math", llvm::toStringRef(CodeGenOpts.NoInfsFPMath)); FuncAttrs.addAttribute("no-nans-fp-math", llvm::toStringRef(CodeGenOpts.NoNaNsFPMath)); FuncAttrs.addAttribute("unsafe-fp-math", llvm::toStringRef(CodeGenOpts.UnsafeFPMath)); FuncAttrs.addAttribute("use-soft-float", llvm::toStringRef(CodeGenOpts.SoftFloat)); FuncAttrs.addAttribute("stack-protector-buffer-size", llvm::utostr(CodeGenOpts.SSPBufferSize)); if (CodeGenOpts.StackRealignment) FuncAttrs.addAttribute("stackrealign"); // Add target-cpu and target-features attributes to functions. If // we have a decl for the function and it has a target attribute then // parse that and add it to the feature set. StringRef TargetCPU = getTarget().getTargetOpts().CPU; const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl); if (FD && FD->hasAttr<TargetAttr>()) { llvm::StringMap<bool> FeatureMap; getFunctionFeatureMap(FeatureMap, FD); // Produce the canonical string for this set of features. std::vector<std::string> Features; for (llvm::StringMap<bool>::const_iterator it = FeatureMap.begin(), ie = FeatureMap.end(); it != ie; ++it) Features.push_back((it->second ? "+" : "-") + it->first().str()); // Now add the target-cpu and target-features to the function. // While we populated the feature map above, we still need to // get and parse the target attribute so we can get the cpu for // the function. const auto *TD = FD->getAttr<TargetAttr>(); TargetAttr::ParsedTargetAttr ParsedAttr = TD->parse(); if (ParsedAttr.second != "") TargetCPU = ParsedAttr.second; if (TargetCPU != "") FuncAttrs.addAttribute("target-cpu", TargetCPU); if (!Features.empty()) { std::sort(Features.begin(), Features.end()); FuncAttrs.addAttribute( "target-features", llvm::join(Features.begin(), Features.end(), ",")); } } else { // Otherwise just add the existing target cpu and target features to the // function. std::vector<std::string> &Features = getTarget().getTargetOpts().Features; if (TargetCPU != "") FuncAttrs.addAttribute("target-cpu", TargetCPU); if (!Features.empty()) { std::sort(Features.begin(), Features.end()); FuncAttrs.addAttribute( "target-features", llvm::join(Features.begin(), Features.end(), ",")); } } } ClangToLLVMArgMapping IRFunctionArgs(getContext(), FI); QualType RetTy = FI.getReturnType(); 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); // FALL THROUGH case ABIArgInfo::Direct: if (RetAI.getInReg()) RetAttrs.addAttribute(llvm::Attribute::InReg); break; case ABIArgInfo::Ignore: break; case ABIArgInfo::InAlloca: case ABIArgInfo::Indirect: { // inalloca and sret disable 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 (const auto *RefTy = RetTy->getAs<ReferenceType>()) { QualType PTy = RefTy->getPointeeType(); if (!PTy->isIncompleteType() && PTy->isConstantSizeType()) RetAttrs.addDereferenceableAttr(getContext().getTypeSizeInChars(PTy) .getQuantity()); else if (getContext().getTargetAddressSpace(PTy) == 0) RetAttrs.addAttribute(llvm::Attribute::NonNull); } // Attach return attributes. if (RetAttrs.hasAttributes()) { PAL.push_back(llvm::AttributeSet::get( getLLVMContext(), llvm::AttributeSet::ReturnIndex, RetAttrs)); } // Attach attributes to sret. if (IRFunctionArgs.hasSRetArg()) { llvm::AttrBuilder SRETAttrs; SRETAttrs.addAttribute(llvm::Attribute::StructRet); if (RetAI.getInReg()) SRETAttrs.addAttribute(llvm::Attribute::InReg); PAL.push_back(llvm::AttributeSet::get( getLLVMContext(), IRFunctionArgs.getSRetArgNo() + 1, SRETAttrs)); } // Attach attributes to inalloca argument. if (IRFunctionArgs.hasInallocaArg()) { llvm::AttrBuilder Attrs; Attrs.addAttribute(llvm::Attribute::InAlloca); PAL.push_back(llvm::AttributeSet::get( getLLVMContext(), IRFunctionArgs.getInallocaArgNo() + 1, Attrs)); } unsigned ArgNo = 0; for (CGFunctionInfo::const_arg_iterator I = FI.arg_begin(), E = FI.arg_end(); I != E; ++I, ++ArgNo) { QualType ParamType = I->type; const ABIArgInfo &AI = I->info; llvm::AttrBuilder Attrs; // Add attribute for padding argument, if necessary. if (IRFunctionArgs.hasPaddingArg(ArgNo)) { if (AI.getPaddingInReg()) PAL.push_back(llvm::AttributeSet::get( getLLVMContext(), IRFunctionArgs.getPaddingArgNo(ArgNo) + 1, llvm::Attribute::InReg)); } // '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()) { if (getTypes().getABIInfo().shouldSignExtUnsignedType(ParamType)) Attrs.addAttribute(llvm::Attribute::SExt); else Attrs.addAttribute(llvm::Attribute::ZExt); } // FALL THROUGH case ABIArgInfo::Direct: if (ArgNo == 0 && FI.isChainCall()) Attrs.addAttribute(llvm::Attribute::Nest); else if (AI.getInReg()) Attrs.addAttribute(llvm::Attribute::InReg); break; case ABIArgInfo::Indirect: { if (AI.getInReg()) Attrs.addAttribute(llvm::Attribute::InReg); if (AI.getIndirectByVal()) Attrs.addAttribute(llvm::Attribute::ByVal); CharUnits Align = AI.getIndirectAlign(); // In a byval argument, it is important that the required // alignment of the type is honored, as LLVM might be creating a // *new* stack object, and needs to know what alignment to give // it. (Sometimes it can deduce a sensible alignment on its own, // but not if clang decides it must emit a packed struct, or the // user specifies increased alignment requirements.) // // This is different from indirect *not* byval, where the object // exists already, and the align attribute is purely // informative. assert(!Align.isZero()); // For now, only add this when we have a byval argument. // TODO: be less lazy about updating test cases. if (AI.getIndirectByVal()) Attrs.addAlignmentAttr(Align.getQuantity()); // byval disables readnone and readonly. FuncAttrs.removeAttribute(llvm::Attribute::ReadOnly) .removeAttribute(llvm::Attribute::ReadNone); break; } case ABIArgInfo::Ignore: case ABIArgInfo::Expand: continue; case ABIArgInfo::InAlloca: // inalloca disables readnone and readonly. FuncAttrs.removeAttribute(llvm::Attribute::ReadOnly) .removeAttribute(llvm::Attribute::ReadNone); continue; } if (const auto *RefTy = ParamType->getAs<ReferenceType>()) { QualType PTy = RefTy->getPointeeType(); if (!PTy->isIncompleteType() && PTy->isConstantSizeType()) Attrs.addDereferenceableAttr(getContext().getTypeSizeInChars(PTy) .getQuantity()); else if (getContext().getTargetAddressSpace(PTy) == 0) Attrs.addAttribute(llvm::Attribute::NonNull); } if (Attrs.hasAttributes()) { unsigned FirstIRArg, NumIRArgs; std::tie(FirstIRArg, NumIRArgs) = IRFunctionArgs.getIRArgs(ArgNo); for (unsigned i = 0; i < NumIRArgs; i++) PAL.push_back(llvm::AttributeSet::get(getLLVMContext(), FirstIRArg + i + 1, Attrs)); } } assert(ArgNo == FI.arg_size()); 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<llvm::IntegerType>(varType)) return CGF.Builder.CreateTrunc(value, varType, "arg.unpromote"); return CGF.Builder.CreateFPCast(value, varType, "arg.unpromote"); } /// Returns the attribute (either parameter attribute, or function /// attribute), which declares argument ArgNo to be non-null. static const NonNullAttr *getNonNullAttr(const Decl *FD, const ParmVarDecl *PVD, QualType ArgType, unsigned ArgNo) { // FIXME: __attribute__((nonnull)) can also be applied to: // - references to pointers, where the pointee is known to be // nonnull (apparently a Clang extension) // - transparent unions containing pointers // In the former case, LLVM IR cannot represent the constraint. In // the latter case, we have no guarantee that the transparent union // is in fact passed as a pointer. if (!ArgType->isAnyPointerType() && !ArgType->isBlockPointerType()) return nullptr; // First, check attribute on parameter itself. if (PVD) { if (auto ParmNNAttr = PVD->getAttr<NonNullAttr>()) return ParmNNAttr; } // Check function attributes. if (!FD) return nullptr; for (const auto *NNAttr : FD->specific_attrs<NonNullAttr>()) { if (NNAttr->isNonNull(ArgNo)) return NNAttr; } return nullptr; } void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI, llvm::Function *Fn, const FunctionArgList &Args) { if (CurCodeDecl && CurCodeDecl->hasAttr<NakedAttr>()) // Naked functions don't have prologues. return; // 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<FunctionDecl>(CurCodeDecl)) { if (FD->hasImplicitReturnZero()) { QualType RetTy = FD->getReturnType().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. ClangToLLVMArgMapping IRFunctionArgs(CGM.getContext(), FI); // Flattened function arguments. SmallVector<llvm::Argument *, 16> FnArgs; FnArgs.reserve(IRFunctionArgs.totalIRArgs()); for (auto &Arg : Fn->args()) { FnArgs.push_back(&Arg); } assert(FnArgs.size() == IRFunctionArgs.totalIRArgs()); // If we're using inalloca, all the memory arguments are GEPs off of the last // parameter, which is a pointer to the complete memory area. Address ArgStruct = Address::invalid(); const llvm::StructLayout *ArgStructLayout = nullptr; if (IRFunctionArgs.hasInallocaArg()) { ArgStructLayout = CGM.getDataLayout().getStructLayout(FI.getArgStruct()); ArgStruct = Address(FnArgs[IRFunctionArgs.getInallocaArgNo()], FI.getArgStructAlignment()); assert(ArgStruct.getType() == FI.getArgStruct()->getPointerTo()); } // Name the struct return parameter. if (IRFunctionArgs.hasSRetArg()) { auto AI = FnArgs[IRFunctionArgs.getSRetArgNo()]; AI->setName("agg.result"); AI->addAttr(llvm::AttributeSet::get(getLLVMContext(), AI->getArgNo() + 1, llvm::Attribute::NoAlias)); } // Track if we received the parameter as a pointer (indirect, byval, or // inalloca). If already have a pointer, EmitParmDecl doesn't need to copy it // into a local alloca for us. SmallVector<ParamValue, 16> ArgVals; ArgVals.reserve(Args.size()); // Create a pointer value for every parameter declaration. This usually // entails copying one or more LLVM IR arguments into an alloca. Don't push // any cleanups or do anything that might unwind. We do that separately, so // we can push the cleanups in the correct order for the ABI. assert(FI.arg_size() == Args.size() && "Mismatch between function signature & arguments."); unsigned ArgNo = 0; 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<ParmVarDecl>(Arg) && cast<ParmVarDecl>(Arg)->isKNRPromoted(); unsigned FirstIRArg, NumIRArgs; std::tie(FirstIRArg, NumIRArgs) = IRFunctionArgs.getIRArgs(ArgNo); switch (ArgI.getKind()) { case ABIArgInfo::InAlloca: { assert(NumIRArgs == 0); auto FieldIndex = ArgI.getInAllocaFieldIndex(); CharUnits FieldOffset = CharUnits::fromQuantity(ArgStructLayout->getElementOffset(FieldIndex)); Address V = Builder.CreateStructGEP(ArgStruct, FieldIndex, FieldOffset, Arg->getName()); ArgVals.push_back(ParamValue::forIndirect(V)); break; } case ABIArgInfo::Indirect: { assert(NumIRArgs == 1); Address ParamAddr = Address(FnArgs[FirstIRArg], ArgI.getIndirectAlign()); if (!hasScalarEvaluationKind(Ty)) { // Aggregates and complex variables are accessed by reference. All we // need to do is realign the value, if requested. Address V = ParamAddr; if (ArgI.getIndirectRealign()) { Address 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. CharUnits Size = getContext().getTypeSizeInChars(Ty); auto SizeVal = llvm::ConstantInt::get(IntPtrTy, Size.getQuantity()); Address Dst = Builder.CreateBitCast(AlignedTemp, Int8PtrTy); Address Src = Builder.CreateBitCast(ParamAddr, Int8PtrTy); Builder.CreateMemCpy(Dst, Src, SizeVal, false); V = AlignedTemp; } ArgVals.push_back(ParamValue::forIndirect(V)); } else { // Load scalar value from indirect argument. llvm::Value *V = EmitLoadOfScalar(ParamAddr, false, Ty, Arg->getLocStart()); if (isPromoted) V = emitArgumentDemotion(*this, Arg, V); ArgVals.push_back(ParamValue::forDirect(V)); } break; } case ABIArgInfo::Extend: case ABIArgInfo::Direct: { // If we have the trivial case, handle it with no muss and fuss. if (!isa<llvm::StructType>(ArgI.getCoerceToType()) && ArgI.getCoerceToType() == ConvertType(Ty) && ArgI.getDirectOffset() == 0) { assert(NumIRArgs == 1); auto AI = FnArgs[FirstIRArg]; llvm::Value *V = AI; if (const ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(Arg)) { if (getNonNullAttr(CurCodeDecl, PVD, PVD->getType(), PVD->getFunctionScopeIndex())) AI->addAttr(llvm::AttributeSet::get(getLLVMContext(), AI->getArgNo() + 1, llvm::Attribute::NonNull)); QualType OTy = PVD->getOriginalType(); if (const auto *ArrTy = getContext().getAsConstantArrayType(OTy)) { // A C99 array parameter declaration with the static keyword also // indicates dereferenceability, and if the size is constant we can // use the dereferenceable attribute (which requires the size in // bytes). if (ArrTy->getSizeModifier() == ArrayType::Static) { QualType ETy = ArrTy->getElementType(); uint64_t ArrSize = ArrTy->getSize().getZExtValue(); if (!ETy->isIncompleteType() && ETy->isConstantSizeType() && ArrSize) { llvm::AttrBuilder Attrs; Attrs.addDereferenceableAttr( getContext().getTypeSizeInChars(ETy).getQuantity()*ArrSize); AI->addAttr(llvm::AttributeSet::get(getLLVMContext(), AI->getArgNo() + 1, Attrs)); } else if (getContext().getTargetAddressSpace(ETy) == 0) { AI->addAttr(llvm::AttributeSet::get(getLLVMContext(), AI->getArgNo() + 1, llvm::Attribute::NonNull)); } } } else if (const auto *ArrTy = getContext().getAsVariableArrayType(OTy)) { // For C99 VLAs with the static keyword, we don't know the size so // we can't use the dereferenceable attribute, but in addrspace(0) // we know that it must be nonnull. if (ArrTy->getSizeModifier() == VariableArrayType::Static && !getContext().getTargetAddressSpace(ArrTy->getElementType())) AI->addAttr(llvm::AttributeSet::get(getLLVMContext(), AI->getArgNo() + 1, llvm::Attribute::NonNull)); } const auto *AVAttr = PVD->getAttr<AlignValueAttr>(); if (!AVAttr) if (const auto *TOTy = dyn_cast<TypedefType>(OTy)) AVAttr = TOTy->getDecl()->getAttr<AlignValueAttr>(); if (AVAttr) { llvm::Value *AlignmentValue = EmitScalarExpr(AVAttr->getAlignment()); llvm::ConstantInt *AlignmentCI = cast<llvm::ConstantInt>(AlignmentValue); unsigned Alignment = std::min((unsigned) AlignmentCI->getZExtValue(), +llvm::Value::MaximumAlignment); llvm::AttrBuilder Attrs; Attrs.addAlignmentAttr(Alignment); AI->addAttr(llvm::AttributeSet::get(getLLVMContext(), AI->getArgNo() + 1, Attrs)); } } 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); if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(CurCodeDecl)) { if (MD->isVirtual() && Arg == CXXABIThisDecl) V = CGM.getCXXABI(). adjustThisParameterInVirtualFunctionPrologue(*this, CurGD, 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); ArgVals.push_back(ParamValue::forDirect(V)); break; } Address Alloca = CreateMemTemp(Ty, getContext().getDeclAlign(Arg), Arg->getName()); // Pointer to store into. Address Ptr = emitAddressAtOffset(*this, Alloca, ArgI); // Fast-isel and the optimizer generally like scalar values better than // FCAs, so we flatten them if this is safe to do for this argument. llvm::StructType *STy = dyn_cast<llvm::StructType>(ArgI.getCoerceToType()); if (ArgI.isDirect() && ArgI.getCanBeFlattened() && STy && STy->getNumElements() > 1) { auto SrcLayout = CGM.getDataLayout().getStructLayout(STy); uint64_t SrcSize = CGM.getDataLayout().getTypeAllocSize(STy); llvm::Type *DstTy = Ptr.getElementType(); uint64_t DstSize = CGM.getDataLayout().getTypeAllocSize(DstTy); Address AddrToStoreInto = Address::invalid(); if (SrcSize <= DstSize) { AddrToStoreInto = Builder.CreateBitCast(Ptr, llvm::PointerType::getUnqual(STy)); } else { AddrToStoreInto = CreateTempAlloca(STy, Alloca.getAlignment(), "coerce"); } assert(STy->getNumElements() == NumIRArgs); for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { auto AI = FnArgs[FirstIRArg + i]; AI->setName(Arg->getName() + ".coerce" + Twine(i)); auto Offset = CharUnits::fromQuantity(SrcLayout->getElementOffset(i)); Address EltPtr = Builder.CreateStructGEP(AddrToStoreInto, i, Offset); Builder.CreateStore(AI, EltPtr); } if (SrcSize > DstSize) { Builder.CreateMemCpy(Ptr, AddrToStoreInto, DstSize); } } else { // Simple case, just do a coerced store of the argument into the alloca. assert(NumIRArgs == 1); auto AI = FnArgs[FirstIRArg]; AI->setName(Arg->getName() + ".coerce"); CreateCoercedStore(AI, Ptr, /*DestIsVolatile=*/false, *this); } // Match to what EmitParmDecl is expecting for this type. if (CodeGenFunction::hasScalarEvaluationKind(Ty)) { llvm::Value *V = EmitLoadOfScalar(Alloca, false, Ty, Arg->getLocStart()); if (isPromoted) V = emitArgumentDemotion(*this, Arg, V); ArgVals.push_back(ParamValue::forDirect(V)); } else { ArgVals.push_back(ParamValue::forIndirect(Alloca)); } break; } case ABIArgInfo::Expand: { // If this structure was expanded into multiple arguments then // we need to create a temporary and reconstruct it from the // arguments. Address Alloca = CreateMemTemp(Ty, getContext().getDeclAlign(Arg)); LValue LV = MakeAddrLValue(Alloca, Ty); ArgVals.push_back(ParamValue::forIndirect(Alloca)); auto FnArgIter = FnArgs.begin() + FirstIRArg; ExpandTypeFromArgs(Ty, LV, FnArgIter); assert(FnArgIter == FnArgs.begin() + FirstIRArg + NumIRArgs); for (unsigned i = 0, e = NumIRArgs; i != e; ++i) { auto AI = FnArgs[FirstIRArg + i]; AI->setName(Arg->getName() + "." + Twine(i)); } break; } case ABIArgInfo::Ignore: assert(NumIRArgs == 0); // Initialize the local variable appropriately. if (!hasScalarEvaluationKind(Ty)) { ArgVals.push_back(ParamValue::forIndirect(CreateMemTemp(Ty))); } else { llvm::Value *U = llvm::UndefValue::get(ConvertType(Arg->getType())); ArgVals.push_back(ParamValue::forDirect(U)); } break; } } if (getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) { for (int I = Args.size() - 1; I >= 0; --I) EmitParmDecl(*Args[I], ArgVals[I], I + 1); } else { for (unsigned I = 0, E = Args.size(); I != E; ++I) EmitParmDecl(*Args[I], ArgVals[I], I + 1); } } static void eraseUnusedBitCasts(llvm::Instruction *insn) { while (insn->use_empty()) { llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(insn); if (!bitcast) return; // This is "safe" because we would have used a ConstantExpr otherwise. insn = cast<llvm::Instruction>(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 nullptr; if (&BB->back() != result) return nullptr; llvm::Type *resultType = result->getType(); // result is in a BasicBlock and is therefore an Instruction. llvm::Instruction *generator = cast<llvm::Instruction>(result); SmallVector<llvm::Instruction*,4> insnsToKill; // Look for: // %generator = bitcast %type1* %generator2 to %type2* while (llvm::BitCastInst *bitcast = dyn_cast<llvm::BitCastInst>(generator)) { // We would have emitted this as a constant if the operand weren't // an Instruction. generator = cast<llvm::Instruction>(bitcast->getOperand(0)); // Require the generator to be immediately followed by the cast. if (generator->getNextNode() != bitcast) return nullptr; 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<llvm::CallInst>(generator); if (!call) return nullptr; bool doRetainAutorelease; if (call->getCalledValue() == CGF.CGM.getObjCEntrypoints().objc_retain) { doRetainAutorelease = true; } else if (call->getCalledValue() == CGF.CGM.getObjCEntrypoints() .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.getObjCEntrypoints().retainAutoreleasedReturnValueMarker) { llvm::Instruction *prev = call->getPrevNode(); assert(prev); if (isa<llvm::BitCastInst>(prev)) { prev = prev->getPrevNode(); assert(prev); } assert(isa<llvm::CallInst>(prev)); assert(cast<llvm::CallInst>(prev)->getCalledValue() == CGF.CGM.getObjCEntrypoints().retainAutoreleasedReturnValueMarker); insnsToKill.push_back(prev); } } else { return nullptr; } 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<llvm::BitCastInst>(result)) { if (!bitcast->hasOneUse()) break; insnsToKill.push_back(bitcast); result = bitcast->getOperand(0); } // Delete all the unnecessary instructions, from latest to earliest. for (SmallVectorImpl<llvm::Instruction*>::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<ObjCMethodDecl>(CGF.CurCodeDecl); if (!method) return nullptr; const VarDecl *self = method->getSelfDecl(); if (!self->getType().isConstQualified()) return nullptr; // Look for a retain call. llvm::CallInst *retainCall = dyn_cast<llvm::CallInst>(result->stripPointerCasts()); if (!retainCall || retainCall->getCalledValue() != CGF.CGM.getObjCEntrypoints().objc_retain) return nullptr; // Look for an ordinary load of 'self'. llvm::Value *retainedValue = retainCall->getArgOperand(0); llvm::LoadInst *load = dyn_cast<llvm::LoadInst>(retainedValue->stripPointerCasts()); if (!load || load->isAtomic() || load->isVolatile() || load->getPointerOperand() != CGF.GetAddrOfLocalVar(self).getPointer()) return nullptr; // 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<llvm::Instruction>(result)); assert(retainCall->use_empty()); retainCall->eraseFromParent(); eraseUnusedBitCasts(cast<llvm::Instruction>(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) { // Check if a User is a store which pointerOperand is the ReturnValue. // We are looking for stores to the ReturnValue, not for stores of the // ReturnValue to some other location. auto GetStoreIfValid = [&CGF](llvm::User *U) -> llvm::StoreInst * { auto *SI = dyn_cast<llvm::StoreInst>(U); if (!SI || SI->getPointerOperand() != CGF.ReturnValue.getPointer()) return nullptr; // These aren't actually possible for non-coerced returns, and we // only care about non-coerced returns on this code path. assert(!SI->isAtomic() && !SI->isVolatile()); return SI; }; // 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.getPointer()->hasOneUse()) { llvm::BasicBlock *IP = CGF.Builder.GetInsertBlock(); if (IP->empty()) return nullptr; llvm::Instruction *I = &IP->back(); // Skip lifetime markers for (llvm::BasicBlock::reverse_iterator II = IP->rbegin(), IE = IP->rend(); II != IE; ++II) { if (llvm::IntrinsicInst *Intrinsic = dyn_cast<llvm::IntrinsicInst>(&*II)) { if (Intrinsic->getIntrinsicID() == llvm::Intrinsic::lifetime_end) { const llvm::Value *CastAddr = Intrinsic->getArgOperand(1); ++II; if (II == IE) break; if (isa<llvm::BitCastInst>(&*II) && (CastAddr == &*II)) continue; } } I = &*II; break; } return GetStoreIfValid(I); } llvm::StoreInst *store = GetStoreIfValid(CGF.ReturnValue.getPointer()->user_back()); if (!store) return nullptr; // 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 nullptr; } // Okay, the store's basic block dominates the insertion point; we // can do our thing. return store; } void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI, bool EmitRetDbgLoc, SourceLocation EndLoc) { if (CurCodeDecl && CurCodeDecl->hasAttr<NakedAttr>()) { // Naked functions don't have epilogues. Builder.CreateUnreachable(); return; } // Functions with no result always return void. if (!ReturnValue.isValid()) { Builder.CreateRetVoid(); return; } llvm::DebugLoc RetDbgLoc; llvm::Value *RV = nullptr; QualType RetTy = FI.getReturnType(); const ABIArgInfo &RetAI = FI.getReturnInfo(); switch (RetAI.getKind()) { case ABIArgInfo::InAlloca: // Aggregrates get evaluated directly into the destination. Sometimes we // need to return the sret value in a register, though. assert(hasAggregateEvaluationKind(RetTy)); if (RetAI.getInAllocaSRet()) { llvm::Function::arg_iterator EI = CurFn->arg_end(); --EI; llvm::Value *ArgStruct = &*EI; llvm::Value *SRet = Builder.CreateStructGEP( nullptr, ArgStruct, RetAI.getInAllocaFieldIndex()); RV = Builder.CreateAlignedLoad(SRet, getPointerAlign(), "sret"); } break; case ABIArgInfo::Indirect: { auto AI = CurFn->arg_begin(); if (RetAI.isSRetAfterThis()) ++AI; switch (getEvaluationKind(RetTy)) { case TEK_Complex: { ComplexPairTy RT = EmitLoadOfComplex(MakeAddrLValue(ReturnValue, RetTy), EndLoc); EmitStoreOfComplex(RT, MakeNaturalAlignAddrLValue(&*AI, 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(&*AI, 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 there is // cleanup code to be emitted between the store and return // instruction. if (EmitRetDbgLoc && !AutoreleaseResult) 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. auto returnValueInst = ReturnValue.getPointer(); if (returnValueInst->use_empty()) { if (auto alloca = dyn_cast<llvm::AllocaInst>(returnValueInst)) { alloca->eraseFromParent(); ReturnValue = Address::invalid(); } } // Otherwise, we have to do a simple load. } else { RV = Builder.CreateLoad(ReturnValue); } } else { // If the value is offset in memory, apply the offset now. Address V = emitAddressAtOffset(*this, ReturnValue, RetAI); 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"); } llvm::Instruction *Ret; if (RV) { if (CurCodeDecl && SanOpts.has(SanitizerKind::ReturnsNonnullAttribute)) { if (auto RetNNAttr = CurCodeDecl->getAttr<ReturnsNonNullAttr>()) { SanitizerScope SanScope(this); llvm::Value *Cond = Builder.CreateICmpNE( RV, llvm::Constant::getNullValue(RV->getType())); llvm::Constant *StaticData[] = { EmitCheckSourceLocation(EndLoc), EmitCheckSourceLocation(RetNNAttr->getLocation()), }; EmitCheck(std::make_pair(Cond, SanitizerKind::ReturnsNonnullAttribute), "nonnull_return", StaticData, None); } } Ret = Builder.CreateRet(RV); } else { Ret = Builder.CreateRetVoid(); } if (RetDbgLoc) Ret->setDebugLoc(std::move(RetDbgLoc)); } static bool isInAllocaArgument(CGCXXABI &ABI, QualType type) { const CXXRecordDecl *RD = type->getAsCXXRecordDecl(); return RD && ABI.getRecordArgABI(RD) == CGCXXABI::RAA_DirectInMemory; } static AggValueSlot createPlaceholderSlot(CodeGenFunction &CGF, QualType Ty) { // FIXME: Generate IR in one pass, rather than going back and fixing up these // placeholders. llvm::Type *IRTy = CGF.ConvertTypeForMem(Ty); llvm::Value *Placeholder = llvm::UndefValue::get(IRTy->getPointerTo()->getPointerTo()); Placeholder = CGF.Builder.CreateDefaultAlignedLoad(Placeholder); // FIXME: When we generate this IR in one pass, we shouldn't need // this win32-specific alignment hack. CharUnits Align = CharUnits::fromQuantity(4); return AggValueSlot::forAddr(Address(Placeholder, Align), Ty.getQualifiers(), AggValueSlot::IsNotDestructed, AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased); } void CodeGenFunction::EmitDelegateCallArg(CallArgList &args, const VarDecl *param, SourceLocation loc) { // StartFunction converted the ABI-lowered parameter(s) into a // local alloca. We need to turn that into an r-value suitable // for EmitCall. Address 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<ReferenceType>()) { 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); } assert(!isInAllocaArgument(CGM.getCXXABI(), type) && "cannot emit delegate call arguments for inalloca arguments!"); args.add(convertTempToRValue(local, type, loc), type); } static bool isProvablyNull(llvm::Value *addr) { return isa<llvm::ConstantPointerNull>(addr); } static bool isProvablyNonNull(llvm::Value *addr) { return isa<llvm::AllocaInst>(addr); } /// Emit the actual writing-back of a writeback. static void emitWriteback(CodeGenFunction &CGF, const CallArgList::Writeback &writeback) { const LValue &srcLV = writeback.Source; Address srcAddr = srcLV.getAddress(); assert(!isProvablyNull(srcAddr.getPointer()) && "shouldn't have writeback for provably null argument"); llvm::BasicBlock *contBB = nullptr; // If the argument wasn't provably non-null, we need to null check // before doing the store. bool provablyNonNull = isProvablyNonNull(srcAddr.getPointer()); if (!provablyNonNull) { llvm::BasicBlock *writebackBB = CGF.createBasicBlock("icr.writeback"); contBB = CGF.createBasicBlock("icr.done"); llvm::Value *isNull = CGF.Builder.CreateIsNull(srcAddr.getPointer(), "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, srcAddr.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, SourceLocation()); // 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 (const auto &I : args.writebacks()) emitWriteback(CGF, I); } static void deactivateArgCleanupsBeforeCall(CodeGenFunction &CGF, const CallArgList &CallArgs) { assert(CGF.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()); ArrayRef<CallArgList::CallArgCleanup> Cleanups = CallArgs.getCleanupsToDeactivate(); // Iterate in reverse to increase the likelihood of popping the cleanup. for (const auto &I : llvm::reverse(Cleanups)) { CGF.DeactivateCleanupBlock(I.Cleanup, I.IsActiveIP); I.IsActiveIP->eraseFromParent(); } } static const Expr *maybeGetUnaryAddrOfOperand(const Expr *E) { if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E->IgnoreParens())) if (uop->getOpcode() == UO_AddrOf) return uop->getSubExpr(); return nullptr; } /// Emit an argument that's being passed call-by-writeback. That is, /// we are passing the address of an __autoreleased temporary; it /// might be copy-initialized with the current value of the given /// address, but it will definitely be copied out of after the call. 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 argument expression is more complicated. if (const Expr *lvExpr = maybeGetUnaryAddrOfOperand(CRE->getSubExpr())) { srcLV = CGF.EmitLValue(lvExpr); // Otherwise, just emit it as a scalar. } else { Address srcAddr = CGF.EmitPointerWithAlignment(CRE->getSubExpr()); QualType srcAddrType = CRE->getSubExpr()->getType()->castAs<PointerType>()->getPointeeType(); srcLV = CGF.MakeAddrLValue(srcAddr, srcAddrType); } Address 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<llvm::PointerType>(CGF.ConvertType(CRE->getType())); // If the address is a constant null, just pass the appropriate null. if (isProvablyNull(srcAddr.getPointer())) { args.add(RValue::get(llvm::ConstantPointerNull::get(destType)), CRE->getType()); return; } // Create the temporary. Address temp = CGF.CreateTempAlloca(destType->getElementType(), CGF.getPointerAlign(), "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<llvm::PointerType>(destType->getElementType())); CGF.Builder.CreateStore(null, temp); } llvm::BasicBlock *contBB = nullptr; llvm::BasicBlock *originBB = nullptr; // If the address is *not* known to be non-null, we need to switch. llvm::Value *finalArgument; bool provablyNonNull = isProvablyNonNull(srcAddr.getPointer()); if (provablyNonNull) { finalArgument = temp.getPointer(); } else { llvm::Value *isNull = CGF.Builder.CreateIsNull(srcAddr.getPointer(), "icr.isnull"); finalArgument = CGF.Builder.CreateSelect(isNull, llvm::ConstantPointerNull::get(destType), temp.getPointer(), "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 = nullptr; // Perform a copy if necessary. if (shouldCopy) { RValue srcRV = CGF.EmitLoadOfLValue(srcLV, SourceLocation()); 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 CallArgList::allocateArgumentMemory(CodeGenFunction &CGF) { assert(!StackBase && !StackCleanup.isValid()); // Save the stack. llvm::Function *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stacksave); StackBase = CGF.Builder.CreateCall(F, {}, "inalloca.save"); } void CallArgList::freeArgumentMemory(CodeGenFunction &CGF) const { if (StackBase) { // Restore the stack after the call. llvm::Value *F = CGF.CGM.getIntrinsic(llvm::Intrinsic::stackrestore); CGF.Builder.CreateCall(F, StackBase); } } void CodeGenFunction::EmitNonNullArgCheck(RValue RV, QualType ArgType, SourceLocation ArgLoc, const FunctionDecl *FD, unsigned ParmNum) { if (!SanOpts.has(SanitizerKind::NonnullAttribute) || !FD) return; auto PVD = ParmNum < FD->getNumParams() ? FD->getParamDecl(ParmNum) : nullptr; unsigned ArgNo = PVD ? PVD->getFunctionScopeIndex() : ParmNum; auto NNAttr = getNonNullAttr(FD, PVD, ArgType, ArgNo); if (!NNAttr) return; SanitizerScope SanScope(this); assert(RV.isScalar()); llvm::Value *V = RV.getScalarVal(); llvm::Value *Cond = Builder.CreateICmpNE(V, llvm::Constant::getNullValue(V->getType())); llvm::Constant *StaticData[] = { EmitCheckSourceLocation(ArgLoc), EmitCheckSourceLocation(NNAttr->getLocation()), llvm::ConstantInt::get(Int32Ty, ArgNo + 1), }; EmitCheck(std::make_pair(Cond, SanitizerKind::NonnullAttribute), "nonnull_arg", StaticData, None); } void CodeGenFunction::EmitCallArgs( CallArgList &Args, ArrayRef<QualType> ArgTypes, llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange, const FunctionDecl *CalleeDecl, unsigned ParamsToSkip) { assert((int)ArgTypes.size() == (ArgRange.end() - ArgRange.begin())); auto MaybeEmitImplicitObjectSize = [&](unsigned I, const Expr *Arg) { if (CalleeDecl == nullptr || I >= CalleeDecl->getNumParams()) return; auto *PS = CalleeDecl->getParamDecl(I)->getAttr<PassObjectSizeAttr>(); if (PS == nullptr) return; const auto &Context = getContext(); auto SizeTy = Context.getSizeType(); auto T = Builder.getIntNTy(Context.getTypeSize(SizeTy)); llvm::Value *V = evaluateOrEmitBuiltinObjectSize(Arg, PS->getType(), T); Args.add(RValue::get(V), SizeTy); }; // We *have* to evaluate arguments from right to left in the MS C++ ABI, // because arguments are destroyed left to right in the callee. if (CGM.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) { // Insert a stack save if we're going to need any inalloca args. bool HasInAllocaArgs = false; for (ArrayRef<QualType>::iterator I = ArgTypes.begin(), E = ArgTypes.end(); I != E && !HasInAllocaArgs; ++I) HasInAllocaArgs = isInAllocaArgument(CGM.getCXXABI(), *I); if (HasInAllocaArgs) { assert(getTarget().getTriple().getArch() == llvm::Triple::x86); Args.allocateArgumentMemory(*this); } // Evaluate each argument. size_t CallArgsStart = Args.size(); for (int I = ArgTypes.size() - 1; I >= 0; --I) { CallExpr::const_arg_iterator Arg = ArgRange.begin() + I; EmitCallArg(Args, *Arg, ArgTypes[I]); EmitNonNullArgCheck(Args.back().RV, ArgTypes[I], (*Arg)->getExprLoc(), CalleeDecl, ParamsToSkip + I); MaybeEmitImplicitObjectSize(I, *Arg); } // Un-reverse the arguments we just evaluated so they match up with the LLVM // IR function. std::reverse(Args.begin() + CallArgsStart, Args.end()); return; } for (unsigned I = 0, E = ArgTypes.size(); I != E; ++I) { CallExpr::const_arg_iterator Arg = ArgRange.begin() + I; assert(Arg != ArgRange.end()); EmitCallArg(Args, *Arg, ArgTypes[I]); EmitNonNullArgCheck(Args.back().RV, ArgTypes[I], (*Arg)->getExprLoc(), CalleeDecl, ParamsToSkip + I); MaybeEmitImplicitObjectSize(I, *Arg); } } namespace { struct DestroyUnpassedArg final : EHScopeStack::Cleanup { DestroyUnpassedArg(Address Addr, QualType Ty) : Addr(Addr), Ty(Ty) {} Address Addr; QualType Ty; void Emit(CodeGenFunction &CGF, Flags flags) override { const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); assert(!Dtor->isTrivial()); CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete, /*for vbase*/ false, /*Delegating=*/false, Addr); } }; struct DisableDebugLocationUpdates { CodeGenFunction &CGF; bool disabledDebugInfo; DisableDebugLocationUpdates(CodeGenFunction &CGF, const Expr *E) : CGF(CGF) { if ((disabledDebugInfo = isa<CXXDefaultArgExpr>(E) && CGF.getDebugInfo())) CGF.disableDebugInfo(); } ~DisableDebugLocationUpdates() { if (disabledDebugInfo) CGF.enableDebugInfo(); } }; } // end anonymous namespace void CodeGenFunction::EmitCallArg(CallArgList &args, const Expr *E, QualType type) { DisableDebugLocationUpdates Dis(*this, E); if (const ObjCIndirectCopyRestoreExpr *CRE = dyn_cast<ObjCIndirectCopyRestoreExpr>(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), type); } bool HasAggregateEvalKind = hasAggregateEvaluationKind(type); // In the Microsoft C++ ABI, aggregate arguments are destructed by the callee. // However, we still have to push an EH-only cleanup in case we unwind before // we make it to the call. if (HasAggregateEvalKind && CGM.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) { // If we're using inalloca, use the argument memory. Otherwise, use a // temporary. AggValueSlot Slot; if (args.isUsingInAlloca()) Slot = createPlaceholderSlot(*this, type); else Slot = CreateAggTemp(type, "agg.tmp"); const CXXRecordDecl *RD = type->getAsCXXRecordDecl(); bool DestroyedInCallee = RD && RD->hasNonTrivialDestructor() && CGM.getCXXABI().getRecordArgABI(RD) != CGCXXABI::RAA_Default; if (DestroyedInCallee) Slot.setExternallyDestructed(); EmitAggExpr(E, Slot); RValue RV = Slot.asRValue(); args.add(RV, type); if (DestroyedInCallee) { // Create a no-op GEP between the placeholder and the cleanup so we can // RAUW it successfully. It also serves as a marker of the first // instruction where the cleanup is active. pushFullExprCleanup<DestroyUnpassedArg>(EHCleanup, Slot.getAddress(), type); // This unreachable is a temporary marker which will be removed later. llvm::Instruction *IsActive = Builder.CreateUnreachable(); args.addArgCleanupDeactivation(EHStack.getInnermostEHScope(), IsActive); } return; } if (HasAggregateEvalKind && isa<ImplicitCastExpr>(E) && cast<CastExpr>(E)->getCastKind() == CK_LValueToRValue) { LValue L = EmitLValue(cast<CastExpr>(E)->getSubExpr()); assert(L.isSimple()); if (L.getAlignment() >= getContext().getTypeAlignInChars(type)) { args.add(L.asAggregateRValue(), type, /*NeedsCopy*/true); } else { // We can't represent a misaligned lvalue in the CallArgList, so copy // to an aligned temporary now. Address tmp = CreateMemTemp(type); EmitAggregateCopy(tmp, L.getAddress(), type, L.isVolatile()); args.add(RValue::getAggregate(tmp), type); } return; } args.add(EmitAnyExprToTemp(E), type); } QualType CodeGenFunction::getVarArgType(const Expr *Arg) { // System headers on Windows define NULL to 0 instead of 0LL on Win64. MSVC // implicitly widens null pointer constants that are arguments to varargs // functions to pointer-sized ints. if (!getTarget().getTriple().isOSWindows()) return Arg->getType(); if (Arg->getType()->isIntegerType() && getContext().getTypeSize(Arg->getType()) < getContext().getTargetInfo().getPointerWidth(0) && Arg->isNullPointerConstant(getContext(), Expr::NPC_ValueDependentIsNotNull)) { return getContext().getIntPtrType(); } return Arg->getType(); } // 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, None, name); } /// Emits a call to the given nounwind runtime function. llvm::CallInst * CodeGenFunction::EmitNounwindRuntimeCall(llvm::Value *callee, ArrayRef<llvm::Value*> 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, None, name); } /// Emits a simple call (never an invoke) to the given runtime /// function. llvm::CallInst * CodeGenFunction::EmitRuntimeCall(llvm::Value *callee, ArrayRef<llvm::Value*> args, const llvm::Twine &name) { llvm::CallInst *call = Builder.CreateCall(callee, args, name); call->setCallingConv(getRuntimeCC()); return call; } // Calls which may throw must have operand bundles indicating which funclet // they are nested within. static void getBundlesForFunclet(llvm::Value *Callee, llvm::Instruction *CurrentFuncletPad, SmallVectorImpl<llvm::OperandBundleDef> &BundleList) { // There is no need for a funclet operand bundle if we aren't inside a funclet. if (!CurrentFuncletPad) return; // Skip intrinsics which cannot throw. auto *CalleeFn = dyn_cast<llvm::Function>(Callee->stripPointerCasts()); if (CalleeFn && CalleeFn->isIntrinsic() && CalleeFn->doesNotThrow()) return; BundleList.emplace_back("funclet", CurrentFuncletPad); } /// Emits a call or invoke to the given noreturn runtime function. void CodeGenFunction::EmitNoreturnRuntimeCallOrInvoke(llvm::Value *callee, ArrayRef<llvm::Value*> args) { SmallVector<llvm::OperandBundleDef, 1> BundleList; getBundlesForFunclet(callee, CurrentFuncletPad, BundleList); if (getInvokeDest()) { llvm::InvokeInst *invoke = Builder.CreateInvoke(callee, getUnreachableBlock(), getInvokeDest(), args, BundleList); invoke->setDoesNotReturn(); invoke->setCallingConv(getRuntimeCC()); } else { llvm::CallInst *call = Builder.CreateCall(callee, args, BundleList); 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, None, name); } /// Emits a call or invoke instruction to the given runtime function. llvm::CallSite CodeGenFunction::EmitRuntimeCallOrInvoke(llvm::Value *callee, ArrayRef<llvm::Value*> args, const Twine &name) { llvm::CallSite callSite = EmitCallOrInvoke(callee, args, name); callSite.setCallingConv(getRuntimeCC()); return callSite; } /// 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<llvm::Value *> 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 llvm::CallSite(Inst); } /// \brief Store a non-aggregate value to an address to initialize it. For /// initialization, a non-atomic store will be used. static void EmitInitStoreOfNonAggregate(CodeGenFunction &CGF, RValue Src, LValue Dst) { if (Src.isScalar()) CGF.EmitStoreOfScalar(Src.getScalarVal(), Dst, /*init=*/true); else CGF.EmitStoreOfComplex(Src.getComplexVal(), Dst, /*init=*/true); } void CodeGenFunction::deferPlaceholderReplacement(llvm::Instruction *Old, llvm::Value *New) { DeferredReplacements.push_back(std::make_pair(Old, New)); } RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo, llvm::Value *Callee, ReturnValueSlot ReturnValue, const CallArgList &CallArgs, CGCalleeInfo CalleeInfo, llvm::Instruction **callOrInvoke) { // FIXME: We no longer need the types from CallArgs; lift up and simplify. // 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(); llvm::FunctionType *IRFuncTy = cast<llvm::FunctionType>( cast<llvm::PointerType>(Callee->getType())->getElementType()); // If we're using inalloca, insert the allocation after the stack save. // FIXME: Do this earlier rather than hacking it in here! Address ArgMemory = Address::invalid(); const llvm::StructLayout *ArgMemoryLayout = nullptr; if (llvm::StructType *ArgStruct = CallInfo.getArgStruct()) { ArgMemoryLayout = CGM.getDataLayout().getStructLayout(ArgStruct); llvm::Instruction *IP = CallArgs.getStackBase(); llvm::AllocaInst *AI; if (IP) { IP = IP->getNextNode(); AI = new llvm::AllocaInst(ArgStruct, "argmem", IP); } else { AI = CreateTempAlloca(ArgStruct, "argmem"); } auto Align = CallInfo.getArgStructAlignment(); AI->setAlignment(Align.getQuantity()); AI->setUsedWithInAlloca(true); assert(AI->isUsedWithInAlloca() && !AI->isStaticAlloca()); ArgMemory = Address(AI, Align); } // Helper function to drill into the inalloca allocation. auto createInAllocaStructGEP = [&](unsigned FieldIndex) -> Address { auto FieldOffset = CharUnits::fromQuantity(ArgMemoryLayout->getElementOffset(FieldIndex)); return Builder.CreateStructGEP(ArgMemory, FieldIndex, FieldOffset); }; ClangToLLVMArgMapping IRFunctionArgs(CGM.getContext(), CallInfo); SmallVector<llvm::Value *, 16> IRCallArgs(IRFunctionArgs.totalIRArgs()); // If the call returns a temporary with struct return, create a temporary // alloca to hold the result, unless one is given to us. Address SRetPtr = Address::invalid(); size_t UnusedReturnSize = 0; if (RetAI.isIndirect() || RetAI.isInAlloca()) { if (!ReturnValue.isNull()) { SRetPtr = ReturnValue.getValue(); } else { SRetPtr = CreateMemTemp(RetTy); if (HaveInsertPoint() && ReturnValue.isUnused()) { uint64_t size = CGM.getDataLayout().getTypeAllocSize(ConvertTypeForMem(RetTy)); if (EmitLifetimeStart(size, SRetPtr.getPointer())) UnusedReturnSize = size; } } if (IRFunctionArgs.hasSRetArg()) { IRCallArgs[IRFunctionArgs.getSRetArgNo()] = SRetPtr.getPointer(); } else { Address Addr = createInAllocaStructGEP(RetAI.getInAllocaFieldIndex()); Builder.CreateStore(SRetPtr.getPointer(), Addr); } } assert(CallInfo.arg_size() == CallArgs.size() && "Mismatch between function signature & arguments."); unsigned ArgNo = 0; CGFunctionInfo::const_arg_iterator info_it = CallInfo.arg_begin(); for (CallArgList::const_iterator I = CallArgs.begin(), E = CallArgs.end(); I != E; ++I, ++info_it, ++ArgNo) { const ABIArgInfo &ArgInfo = info_it->info; RValue RV = I->RV; // Insert a padding argument to ensure proper alignment. if (IRFunctionArgs.hasPaddingArg(ArgNo)) IRCallArgs[IRFunctionArgs.getPaddingArgNo(ArgNo)] = llvm::UndefValue::get(ArgInfo.getPaddingType()); unsigned FirstIRArg, NumIRArgs; std::tie(FirstIRArg, NumIRArgs) = IRFunctionArgs.getIRArgs(ArgNo); switch (ArgInfo.getKind()) { case ABIArgInfo::InAlloca: { assert(NumIRArgs == 0); assert(getTarget().getTriple().getArch() == llvm::Triple::x86); if (RV.isAggregate()) { // Replace the placeholder with the appropriate argument slot GEP. llvm::Instruction *Placeholder = cast<llvm::Instruction>(RV.getAggregatePointer()); CGBuilderTy::InsertPoint IP = Builder.saveIP(); Builder.SetInsertPoint(Placeholder); Address Addr = createInAllocaStructGEP(ArgInfo.getInAllocaFieldIndex()); Builder.restoreIP(IP); deferPlaceholderReplacement(Placeholder, Addr.getPointer()); } else { // Store the RValue into the argument struct. Address Addr = createInAllocaStructGEP(ArgInfo.getInAllocaFieldIndex()); unsigned AS = Addr.getType()->getPointerAddressSpace(); llvm::Type *MemType = ConvertTypeForMem(I->Ty)->getPointerTo(AS); // There are some cases where a trivial bitcast is not avoidable. The // definition of a type later in a translation unit may change it's type // from {}* to (%struct.foo*)*. if (Addr.getType() != MemType) Addr = Builder.CreateBitCast(Addr, MemType); LValue argLV = MakeAddrLValue(Addr, I->Ty); EmitInitStoreOfNonAggregate(*this, RV, argLV); } break; } case ABIArgInfo::Indirect: { assert(NumIRArgs == 1); if (RV.isScalar() || RV.isComplex()) { // Make a temporary alloca to pass the argument. Address Addr = CreateMemTemp(I->Ty, ArgInfo.getIndirectAlign()); IRCallArgs[FirstIRArg] = Addr.getPointer(); LValue argLV = MakeAddrLValue(Addr, I->Ty); EmitInitStoreOfNonAggregate(*this, RV, argLV); } 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). Address Addr = RV.getAggregateAddress(); CharUnits Align = ArgInfo.getIndirectAlign(); const llvm::DataLayout *TD = &CGM.getDataLayout(); const unsigned RVAddrSpace = Addr.getType()->getAddressSpace(); const unsigned ArgAddrSpace = (FirstIRArg < IRFuncTy->getNumParams() ? IRFuncTy->getParamType(FirstIRArg)->getPointerAddressSpace() : 0); if ((!ArgInfo.getIndirectByVal() && I->NeedsCopy) || (ArgInfo.getIndirectByVal() && Addr.getAlignment() < Align && llvm::getOrEnforceKnownAlignment(Addr.getPointer(), Align.getQuantity(), *TD) < Align.getQuantity()) || (ArgInfo.getIndirectByVal() && (RVAddrSpace != ArgAddrSpace))) { // Create an aligned temporary, and copy to it. Address AI = CreateMemTemp(I->Ty, ArgInfo.getIndirectAlign()); IRCallArgs[FirstIRArg] = AI.getPointer(); EmitAggregateCopy(AI, Addr, I->Ty, RV.isVolatileQualified()); } else { // Skip the extra memcpy call. IRCallArgs[FirstIRArg] = Addr.getPointer(); } } break; } case ABIArgInfo::Ignore: assert(NumIRArgs == 0); break; case ABIArgInfo::Extend: case ABIArgInfo::Direct: { if (!isa<llvm::StructType>(ArgInfo.getCoerceToType()) && ArgInfo.getCoerceToType() == ConvertType(info_it->type) && ArgInfo.getDirectOffset() == 0) { assert(NumIRArgs == 1); llvm::Value *V; if (RV.isScalar()) V = RV.getScalarVal(); else V = Builder.CreateLoad(RV.getAggregateAddress()); // We might have to widen integers, but we should never truncate. if (ArgInfo.getCoerceToType() != V->getType() && V->getType()->isIntegerTy()) V = Builder.CreateZExt(V, ArgInfo.getCoerceToType()); // If the argument doesn't match, perform a bitcast to coerce it. This // can happen due to trivial type mismatches. if (FirstIRArg < IRFuncTy->getNumParams() && V->getType() != IRFuncTy->getParamType(FirstIRArg)) V = Builder.CreateBitCast(V, IRFuncTy->getParamType(FirstIRArg)); IRCallArgs[FirstIRArg] = V; break; } // FIXME: Avoid the conversion through memory if possible. Address Src = Address::invalid(); if (RV.isScalar() || RV.isComplex()) { Src = CreateMemTemp(I->Ty, "coerce"); LValue SrcLV = MakeAddrLValue(Src, I->Ty); EmitInitStoreOfNonAggregate(*this, RV, SrcLV); } else { Src = RV.getAggregateAddress(); } // If the value is offset in memory, apply the offset now. Src = emitAddressAtOffset(*this, Src, ArgInfo); // Fast-isel and the optimizer generally like scalar values better than // FCAs, so we flatten them if this is safe to do for this argument. llvm::StructType *STy = dyn_cast<llvm::StructType>(ArgInfo.getCoerceToType()); if (STy && ArgInfo.isDirect() && ArgInfo.getCanBeFlattened()) { llvm::Type *SrcTy = Src.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) { Address TempAlloca = CreateTempAlloca(STy, Src.getAlignment(), Src.getName() + ".coerce"); Builder.CreateMemCpy(TempAlloca, Src, SrcSize); Src = TempAlloca; } else { Src = Builder.CreateBitCast(Src, llvm::PointerType::getUnqual(STy)); } auto SrcLayout = CGM.getDataLayout().getStructLayout(STy); assert(NumIRArgs == STy->getNumElements()); for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { auto Offset = CharUnits::fromQuantity(SrcLayout->getElementOffset(i)); Address EltPtr = Builder.CreateStructGEP(Src, i, Offset); llvm::Value *LI = Builder.CreateLoad(EltPtr); IRCallArgs[FirstIRArg + i] = LI; } } else { // In the simple case, just pass the coerced loaded value. assert(NumIRArgs == 1); IRCallArgs[FirstIRArg] = CreateCoercedLoad(Src, ArgInfo.getCoerceToType(), *this); } break; } case ABIArgInfo::Expand: unsigned IRArgPos = FirstIRArg; ExpandTypeToArgs(I->Ty, RV, IRFuncTy, IRCallArgs, IRArgPos); assert(IRArgPos == FirstIRArg + NumIRArgs); break; } } if (ArgMemory.isValid()) { llvm::Value *Arg = ArgMemory.getPointer(); if (CallInfo.isVariadic()) { // When passing non-POD arguments by value to variadic functions, we will // end up with a variadic prototype and an inalloca call site. In such // cases, we can't do any parameter mismatch checks. Give up and bitcast // the callee. unsigned CalleeAS = cast<llvm::PointerType>(Callee->getType())->getAddressSpace(); Callee = Builder.CreateBitCast( Callee, getTypes().GetFunctionType(CallInfo)->getPointerTo(CalleeAS)); } else { llvm::Type *LastParamTy = IRFuncTy->getParamType(IRFuncTy->getNumParams() - 1); if (Arg->getType() != LastParamTy) { #ifndef NDEBUG // Assert that these structs have equivalent element types. llvm::StructType *FullTy = CallInfo.getArgStruct(); llvm::StructType *DeclaredTy = cast<llvm::StructType>( cast<llvm::PointerType>(LastParamTy)->getElementType()); assert(DeclaredTy->getNumElements() == FullTy->getNumElements()); for (llvm::StructType::element_iterator DI = DeclaredTy->element_begin(), DE = DeclaredTy->element_end(), FI = FullTy->element_begin(); DI != DE; ++DI, ++FI) assert(*DI == *FI); #endif Arg = Builder.CreateBitCast(Arg, LastParamTy); } } assert(IRFunctionArgs.hasInallocaArg()); IRCallArgs[IRFunctionArgs.getInallocaArgNo()] = Arg; } if (!CallArgs.getCleanupsToDeactivate().empty()) deactivateArgCleanupsBeforeCall(*this, CallArgs); // 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<llvm::ConstantExpr>(Callee)) if (llvm::Function *CalleeF = dyn_cast<llvm::Function>(CE->getOperand(0))) { llvm::PointerType *CurPT=cast<llvm::PointerType>(Callee->getType()); llvm::FunctionType *CurFT = cast<llvm::FunctionType>(CurPT->getElementType()); llvm::FunctionType *ActualFT = CalleeF->getFunctionType(); if (CE->getOpcode() == llvm::Instruction::BitCast && ActualFT->getReturnType() == CurFT->getReturnType() && ActualFT->getNumParams() == CurFT->getNumParams() && ActualFT->getNumParams() == IRCallArgs.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; } } assert(IRCallArgs.size() == IRFuncTy->getNumParams() || IRFuncTy->isVarArg()); for (unsigned i = 0; i < IRCallArgs.size(); ++i) { // Inalloca argument can have different type. if (IRFunctionArgs.hasInallocaArg() && i == IRFunctionArgs.getInallocaArgNo()) continue; if (i < IRFuncTy->getNumParams()) assert(IRCallArgs[i]->getType() == IRFuncTy->getParamType(i)); } unsigned CallingConv; CodeGen::AttributeListType AttributeList; CGM.ConstructAttributeList(CallInfo, CalleeInfo, AttributeList, CallingConv, true); llvm::AttributeSet Attrs = llvm::AttributeSet::get(getLLVMContext(), AttributeList); bool CannotThrow; if (currentFunctionUsesSEHTry()) { // SEH cares about asynchronous exceptions, everything can "throw." CannotThrow = false; } else if (isCleanupPadScope() && EHPersonality::get(*this).isMSVCXXPersonality()) { // The MSVC++ personality will implicitly terminate the program if an // exception is thrown. An unwind edge cannot be reached. CannotThrow = true; } else { // Otherwise, nowunind callsites will never throw. CannotThrow = Attrs.hasAttribute(llvm::AttributeSet::FunctionIndex, llvm::Attribute::NoUnwind); } llvm::BasicBlock *InvokeDest = CannotThrow ? nullptr : getInvokeDest(); SmallVector<llvm::OperandBundleDef, 1> BundleList; getBundlesForFunclet(Callee, CurrentFuncletPad, BundleList); llvm::CallSite CS; if (!InvokeDest) { CS = Builder.CreateCall(Callee, IRCallArgs, BundleList); } else { llvm::BasicBlock *Cont = createBasicBlock("invoke.cont"); CS = Builder.CreateInvoke(Callee, Cont, InvokeDest, IRCallArgs, BundleList); EmitBlock(Cont); } if (callOrInvoke) *callOrInvoke = CS.getInstruction(); if (CurCodeDecl && CurCodeDecl->hasAttr<FlattenAttr>() && !CS.hasFnAttr(llvm::Attribute::NoInline)) Attrs = Attrs.addAttribute(getLLVMContext(), llvm::AttributeSet::FunctionIndex, llvm::Attribute::AlwaysInline); // Disable inlining inside SEH __try blocks. if (isSEHTryScope()) Attrs = Attrs.addAttribute(getLLVMContext(), llvm::AttributeSet::FunctionIndex, llvm::Attribute::NoInline); CS.setAttributes(Attrs); CS.setCallingConv(static_cast<llvm::CallingConv::ID>(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()) { if (UnusedReturnSize) EmitLifetimeEnd(llvm::ConstantInt::get(Int64Ty, UnusedReturnSize), SRetPtr.getPointer()); 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); // The stack cleanup for inalloca arguments has to run out of the normal // lexical order, so deactivate it and run it manually here. CallArgs.freeArgumentMemory(*this); if (llvm::CallInst *Call = dyn_cast<llvm::CallInst>(CI)) { const Decl *TargetDecl = CalleeInfo.getCalleeDecl(); if (TargetDecl && TargetDecl->hasAttr<NotTailCalledAttr>()) Call->setTailCallKind(llvm::CallInst::TCK_NoTail); } RValue Ret = [&] { switch (RetAI.getKind()) { case ABIArgInfo::InAlloca: case ABIArgInfo::Indirect: { RValue ret = convertTempToRValue(SRetPtr, RetTy, SourceLocation()); if (UnusedReturnSize) EmitLifetimeEnd(llvm::ConstantInt::get(Int64Ty, UnusedReturnSize), SRetPtr.getPointer()); return ret; } 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: { Address DestPtr = ReturnValue.getValue(); bool DestIsVolatile = ReturnValue.isVolatile(); if (!DestPtr.isValid()) { DestPtr = CreateMemTemp(RetTy, "agg.tmp"); DestIsVolatile = false; } BuildAggStore(*this, CI, DestPtr, DestIsVolatile); 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"); } Address DestPtr = ReturnValue.getValue(); bool DestIsVolatile = ReturnValue.isVolatile(); if (!DestPtr.isValid()) { DestPtr = CreateMemTemp(RetTy, "coerce"); DestIsVolatile = false; } // If the value is offset in memory, apply the offset now. Address StorePtr = emitAddressAtOffset(*this, DestPtr, RetAI); CreateCoercedStore(CI, StorePtr, DestIsVolatile, *this); return convertTempToRValue(DestPtr, RetTy, SourceLocation()); } case ABIArgInfo::Expand: llvm_unreachable("Invalid ABI kind for return argument"); } llvm_unreachable("Unhandled ABIArgInfo::Kind"); } (); const Decl *TargetDecl = CalleeInfo.getCalleeDecl(); if (Ret.isScalar() && TargetDecl) { if (const auto *AA = TargetDecl->getAttr<AssumeAlignedAttr>()) { llvm::Value *OffsetValue = nullptr; if (const auto *Offset = AA->getOffset()) OffsetValue = EmitScalarExpr(Offset); llvm::Value *Alignment = EmitScalarExpr(AA->getAlignment()); llvm::ConstantInt *AlignmentCI = cast<llvm::ConstantInt>(Alignment); EmitAlignmentAssumption(Ret.getScalarVal(), AlignmentCI->getZExtValue(), OffsetValue); } } return Ret; } /* VarArg handling */ Address CodeGenFunction::EmitVAArg(VAArgExpr *VE, Address &VAListAddr) { VAListAddr = VE->isMicrosoftABI() ? EmitMSVAListRef(VE->getSubExpr()) : EmitVAListRef(VE->getSubExpr()); QualType Ty = VE->getType(); if (VE->isMicrosoftABI()) return CGM.getTypes().getABIInfo().EmitMSVAArg(*this, VAListAddr, Ty); return CGM.getTypes().getABIInfo().EmitVAArg(*this, VAListAddr, Ty); }