//===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // These classes wrap the information about a call or function // definition used to handle ABI compliancy. // //===----------------------------------------------------------------------===// #include "CGCall.h" #include "ABIInfo.h" #include "CodeGenFunction.h" #include "CodeGenModule.h" #include "clang/Basic/TargetInfo.h" #include "clang/AST/Decl.h" #include "clang/AST/DeclCXX.h" #include "clang/AST/DeclObjC.h" #include "clang/Frontend/CodeGenOptions.h" #include "llvm/Attributes.h" #include "llvm/Support/CallSite.h" #include "llvm/Target/TargetData.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; } } /// Derives the 'this' type for codegen purposes, i.e. ignoring method /// qualification. /// FIXME: address space qualification? static CanQualType GetThisType(ASTContext &Context, const CXXRecordDecl *RD) { QualType RecTy = Context.getTagDeclType(RD)->getCanonicalTypeInternal(); return Context.getPointerType(CanQualType::CreateUnsafe(RecTy)); } /// Returns the canonical formal type of the given C++ method. static CanQual GetFormalType(const CXXMethodDecl *MD) { return MD->getType()->getCanonicalTypeUnqualified() .getAs(); } /// Returns the "extra-canonicalized" return type, which discards /// qualifiers on the return type. Codegen doesn't care about them, /// and it makes ABI code a little easier to be able to assume that /// all parameter and return types are top-level unqualified. static CanQualType GetReturnType(QualType RetTy) { return RetTy->getCanonicalTypeUnqualified().getUnqualifiedType(); } const CGFunctionInfo & CodeGenTypes::getFunctionInfo(CanQual FTNP, bool IsRecursive) { return getFunctionInfo(FTNP->getResultType().getUnqualifiedType(), llvm::SmallVector(), FTNP->getExtInfo(), IsRecursive); } /// \param Args - contains any initial parameters besides those /// in the formal type static const CGFunctionInfo &getFunctionInfo(CodeGenTypes &CGT, llvm::SmallVectorImpl &ArgTys, CanQual FTP, bool IsRecursive = false) { // FIXME: Kill copy. for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i) ArgTys.push_back(FTP->getArgType(i)); CanQualType ResTy = FTP->getResultType().getUnqualifiedType(); return CGT.getFunctionInfo(ResTy, ArgTys, FTP->getExtInfo(), IsRecursive); } const CGFunctionInfo & CodeGenTypes::getFunctionInfo(CanQual FTP, bool IsRecursive) { llvm::SmallVector ArgTys; return ::getFunctionInfo(*this, ArgTys, FTP, IsRecursive); } static CallingConv getCallingConventionForDecl(const Decl *D) { // Set the appropriate calling convention for the Function. if (D->hasAttr()) return CC_X86StdCall; if (D->hasAttr()) return CC_X86FastCall; if (D->hasAttr()) return CC_X86ThisCall; return CC_C; } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXRecordDecl *RD, const FunctionProtoType *FTP) { llvm::SmallVector ArgTys; // Add the 'this' pointer. ArgTys.push_back(GetThisType(Context, RD)); return ::getFunctionInfo(*this, ArgTys, FTP->getCanonicalTypeUnqualified().getAs()); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXMethodDecl *MD) { llvm::SmallVector ArgTys; // Add the 'this' pointer unless this is a static method. if (MD->isInstance()) ArgTys.push_back(GetThisType(Context, MD->getParent())); return ::getFunctionInfo(*this, ArgTys, GetFormalType(MD)); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXConstructorDecl *D, CXXCtorType Type) { llvm::SmallVector ArgTys; // Add the 'this' pointer. ArgTys.push_back(GetThisType(Context, D->getParent())); // Check if we need to add a VTT parameter (which has type void **). if (Type == Ctor_Base && D->getParent()->getNumVBases() != 0) ArgTys.push_back(Context.getPointerType(Context.VoidPtrTy)); return ::getFunctionInfo(*this, ArgTys, GetFormalType(D)); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const CXXDestructorDecl *D, CXXDtorType Type) { llvm::SmallVector ArgTys; // Add the 'this' pointer. ArgTys.push_back(GetThisType(Context, D->getParent())); // Check if we need to add a VTT parameter (which has type void **). if (Type == Dtor_Base && D->getParent()->getNumVBases() != 0) ArgTys.push_back(Context.getPointerType(Context.VoidPtrTy)); return ::getFunctionInfo(*this, ArgTys, GetFormalType(D)); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const FunctionDecl *FD) { if (const CXXMethodDecl *MD = dyn_cast(FD)) if (MD->isInstance()) return getFunctionInfo(MD); CanQualType FTy = FD->getType()->getCanonicalTypeUnqualified(); assert(isa(FTy)); if (isa(FTy)) return getFunctionInfo(FTy.getAs()); assert(isa(FTy)); return getFunctionInfo(FTy.getAs()); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const ObjCMethodDecl *MD) { llvm::SmallVector ArgTys; ArgTys.push_back(Context.getCanonicalParamType(MD->getSelfDecl()->getType())); ArgTys.push_back(Context.getCanonicalParamType(Context.getObjCSelType())); // FIXME: Kill copy? for (ObjCMethodDecl::param_iterator i = MD->param_begin(), e = MD->param_end(); i != e; ++i) { ArgTys.push_back(Context.getCanonicalParamType((*i)->getType())); } return getFunctionInfo(GetReturnType(MD->getResultType()), ArgTys, FunctionType::ExtInfo( /*NoReturn*/ false, /*RegParm*/ 0, getCallingConventionForDecl(MD))); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(GlobalDecl GD) { // FIXME: Do we need to handle ObjCMethodDecl? const FunctionDecl *FD = cast(GD.getDecl()); if (const CXXConstructorDecl *CD = dyn_cast(FD)) return getFunctionInfo(CD, GD.getCtorType()); if (const CXXDestructorDecl *DD = dyn_cast(FD)) return getFunctionInfo(DD, GD.getDtorType()); return getFunctionInfo(FD); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy, const CallArgList &Args, const FunctionType::ExtInfo &Info) { // FIXME: Kill copy. llvm::SmallVector ArgTys; for (CallArgList::const_iterator i = Args.begin(), e = Args.end(); i != e; ++i) ArgTys.push_back(Context.getCanonicalParamType(i->second)); return getFunctionInfo(GetReturnType(ResTy), ArgTys, Info); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy, const FunctionArgList &Args, const FunctionType::ExtInfo &Info) { // FIXME: Kill copy. llvm::SmallVector ArgTys; for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); i != e; ++i) ArgTys.push_back(Context.getCanonicalParamType(i->second)); return getFunctionInfo(GetReturnType(ResTy), ArgTys, Info); } const CGFunctionInfo &CodeGenTypes::getFunctionInfo(CanQualType ResTy, const llvm::SmallVectorImpl &ArgTys, const FunctionType::ExtInfo &Info, bool IsRecursive) { #ifndef NDEBUG for (llvm::SmallVectorImpl::const_iterator I = ArgTys.begin(), E = ArgTys.end(); I != E; ++I) assert(I->isCanonicalAsParam()); #endif unsigned CC = ClangCallConvToLLVMCallConv(Info.getCC()); // Lookup or create unique function info. llvm::FoldingSetNodeID ID; CGFunctionInfo::Profile(ID, Info, ResTy, ArgTys.begin(), ArgTys.end()); void *InsertPos = 0; CGFunctionInfo *FI = FunctionInfos.FindNodeOrInsertPos(ID, InsertPos); if (FI) return *FI; // Construct the function info. FI = new CGFunctionInfo(CC, Info.getNoReturn(), Info.getRegParm(), ResTy, ArgTys.data(), ArgTys.size()); FunctionInfos.InsertNode(FI, InsertPos); // ABI lowering wants to know what our preferred type for the argument is in // various situations, pass it in. llvm::SmallVector PreferredArgTypes; for (llvm::SmallVectorImpl::const_iterator I = ArgTys.begin(), E = ArgTys.end(); I != E; ++I) { // If this is being called from the guts of the ConvertType loop, make sure // to call ConvertTypeRecursive so we don't get into issues with cyclic // pointer type structures. PreferredArgTypes.push_back(ConvertTypeRecursive(*I)); } // Compute ABI information. getABIInfo().computeInfo(*FI, getContext(), TheModule.getContext(), PreferredArgTypes.data(), PreferredArgTypes.size()); // If this is a top-level call and ConvertTypeRecursive hit unresolved pointer // types, resolve them now. These pointers may point to this function, which // we *just* filled in the FunctionInfo for. if (!IsRecursive && !PointersToResolve.empty()) { // Use PATypeHolder's so that our preferred types don't dangle under // refinement. llvm::SmallVector Handles(PreferredArgTypes.begin(), PreferredArgTypes.end()); HandleLateResolvedPointers(); PreferredArgTypes.clear(); PreferredArgTypes.append(Handles.begin(), Handles.end()); } return *FI; } CGFunctionInfo::CGFunctionInfo(unsigned _CallingConvention, bool _NoReturn, unsigned _RegParm, CanQualType ResTy, const CanQualType *ArgTys, unsigned NumArgTys) : CallingConvention(_CallingConvention), EffectiveCallingConvention(_CallingConvention), NoReturn(_NoReturn), RegParm(_RegParm) { NumArgs = NumArgTys; // FIXME: Coallocate with the CGFunctionInfo object. Args = new ArgInfo[1 + NumArgTys]; Args[0].type = ResTy; for (unsigned i = 0; i != NumArgTys; ++i) Args[1 + i].type = ArgTys[i]; } /***/ void CodeGenTypes::GetExpandedTypes(QualType Ty, std::vector &ArgTys, bool IsRecursive) { const RecordType *RT = Ty->getAsStructureType(); assert(RT && "Can only expand structure types."); const RecordDecl *RD = RT->getDecl(); assert(!RD->hasFlexibleArrayMember() && "Cannot expand structure with flexible array."); for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { const FieldDecl *FD = *i; assert(!FD->isBitField() && "Cannot expand structure with bit-field members."); QualType FT = FD->getType(); if (CodeGenFunction::hasAggregateLLVMType(FT)) { GetExpandedTypes(FT, ArgTys, IsRecursive); } else { ArgTys.push_back(ConvertType(FT, IsRecursive)); } } } llvm::Function::arg_iterator CodeGenFunction::ExpandTypeFromArgs(QualType Ty, LValue LV, llvm::Function::arg_iterator AI) { const RecordType *RT = Ty->getAsStructureType(); assert(RT && "Can only expand structure types."); RecordDecl *RD = RT->getDecl(); assert(LV.isSimple() && "Unexpected non-simple lvalue during struct expansion."); llvm::Value *Addr = LV.getAddress(); for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { FieldDecl *FD = *i; QualType FT = FD->getType(); // FIXME: What are the right qualifiers here? LValue LV = EmitLValueForField(Addr, FD, 0); if (CodeGenFunction::hasAggregateLLVMType(FT)) { AI = ExpandTypeFromArgs(FT, LV, AI); } else { EmitStoreThroughLValue(RValue::get(AI), LV, FT); ++AI; } } return AI; } void CodeGenFunction::ExpandTypeToArgs(QualType Ty, RValue RV, llvm::SmallVector &Args) { const RecordType *RT = Ty->getAsStructureType(); assert(RT && "Can only expand structure types."); RecordDecl *RD = RT->getDecl(); assert(RV.isAggregate() && "Unexpected rvalue during struct expansion"); llvm::Value *Addr = RV.getAggregateAddr(); for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end(); i != e; ++i) { FieldDecl *FD = *i; QualType FT = FD->getType(); // FIXME: What are the right qualifiers here? LValue LV = EmitLValueForField(Addr, FD, 0); if (CodeGenFunction::hasAggregateLLVMType(FT)) { ExpandTypeToArgs(FT, RValue::getAggregate(LV.getAddress()), Args); } else { RValue RV = EmitLoadOfLValue(LV, FT); assert(RV.isScalar() && "Unexpected non-scalar rvalue during struct expansion."); Args.push_back(RV.getScalarVal()); } } } /// EnterStructPointerForCoercedAccess - Given a struct pointer that we are /// accessing some number of bytes out of it, try to gep into the struct to get /// at its inner goodness. Dive as deep as possible without entering an element /// with an in-memory size smaller than DstSize. static llvm::Value * EnterStructPointerForCoercedAccess(llvm::Value *SrcPtr, const llvm::StructType *SrcSTy, uint64_t DstSize, CodeGenFunction &CGF) { // We can't dive into a zero-element struct. if (SrcSTy->getNumElements() == 0) return SrcPtr; const llvm::Type *FirstElt = SrcSTy->getElementType(0); // If the first elt is at least as large as what we're looking for, or if the // first element is the same size as the whole struct, we can enter it. uint64_t FirstEltSize = CGF.CGM.getTargetData().getTypeAllocSize(FirstElt); if (FirstEltSize < DstSize && FirstEltSize < CGF.CGM.getTargetData().getTypeAllocSize(SrcSTy)) return SrcPtr; // GEP into the first element. SrcPtr = CGF.Builder.CreateConstGEP2_32(SrcPtr, 0, 0, "coerce.dive"); // If the first element is a struct, recurse. const llvm::Type *SrcTy = cast(SrcPtr->getType())->getElementType(); if (const llvm::StructType *SrcSTy = dyn_cast(SrcTy)) return EnterStructPointerForCoercedAccess(SrcPtr, SrcSTy, DstSize, CGF); return SrcPtr; } /// CoerceIntOrPtrToIntOrPtr - Convert a value Val to the specific Ty where both /// are either integers or pointers. This does a truncation of the value if it /// is too large or a zero extension if it is too small. static llvm::Value *CoerceIntOrPtrToIntOrPtr(llvm::Value *Val, const llvm::Type *Ty, CodeGenFunction &CGF) { if (Val->getType() == Ty) return Val; if (isa(Val->getType())) { // If this is Pointer->Pointer avoid conversion to and from int. if (isa(Ty)) return CGF.Builder.CreateBitCast(Val, Ty, "coerce.val"); // Convert the pointer to an integer so we can play with its width. Val = CGF.Builder.CreatePtrToInt(Val, CGF.IntPtrTy, "coerce.val.pi"); } const llvm::Type *DestIntTy = Ty; if (isa(DestIntTy)) DestIntTy = CGF.IntPtrTy; if (Val->getType() != DestIntTy) Val = CGF.Builder.CreateIntCast(Val, DestIntTy, false, "coerce.val.ii"); if (isa(Ty)) Val = CGF.Builder.CreateIntToPtr(Val, Ty, "coerce.val.ip"); return Val; } /// CreateCoercedLoad - Create a load from \arg SrcPtr interpreted as /// a pointer to an object of type \arg Ty. /// /// This safely handles the case when the src type is smaller than the /// destination type; in this situation the values of bits which not /// present in the src are undefined. static llvm::Value *CreateCoercedLoad(llvm::Value *SrcPtr, const llvm::Type *Ty, CodeGenFunction &CGF) { const llvm::Type *SrcTy = cast(SrcPtr->getType())->getElementType(); // If SrcTy and Ty are the same, just do a load. if (SrcTy == Ty) return CGF.Builder.CreateLoad(SrcPtr); uint64_t DstSize = CGF.CGM.getTargetData().getTypeAllocSize(Ty); if (const llvm::StructType *SrcSTy = dyn_cast(SrcTy)) { SrcPtr = EnterStructPointerForCoercedAccess(SrcPtr, SrcSTy, DstSize, CGF); SrcTy = cast(SrcPtr->getType())->getElementType(); } uint64_t SrcSize = CGF.CGM.getTargetData().getTypeAllocSize(SrcTy); // If the source and destination are integer or pointer types, just do an // extension or truncation to the desired type. if ((isa(Ty) || isa(Ty)) && (isa(SrcTy) || isa(SrcTy))) { llvm::LoadInst *Load = CGF.Builder.CreateLoad(SrcPtr); return CoerceIntOrPtrToIntOrPtr(Load, Ty, CGF); } // If load is legal, just bitcast the src pointer. if (SrcSize >= DstSize) { // Generally SrcSize is never greater than DstSize, since this means we are // losing bits. However, this can happen in cases where the structure has // additional padding, for example due to a user specified alignment. // // FIXME: Assert that we aren't truncating non-padding bits when have access // to that information. llvm::Value *Casted = CGF.Builder.CreateBitCast(SrcPtr, llvm::PointerType::getUnqual(Ty)); llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted); // FIXME: Use better alignment / avoid requiring aligned load. Load->setAlignment(1); return Load; } // Otherwise do coercion through memory. This is stupid, but // simple. llvm::Value *Tmp = CGF.CreateTempAlloca(Ty); llvm::Value *Casted = CGF.Builder.CreateBitCast(Tmp, llvm::PointerType::getUnqual(SrcTy)); llvm::StoreInst *Store = CGF.Builder.CreateStore(CGF.Builder.CreateLoad(SrcPtr), Casted); // FIXME: Use better alignment / avoid requiring aligned store. Store->setAlignment(1); return CGF.Builder.CreateLoad(Tmp); } /// CreateCoercedStore - Create a store to \arg DstPtr from \arg Src, /// where the source and destination may have different types. /// /// This safely handles the case when the src type is larger than the /// destination type; the upper bits of the src will be lost. static void CreateCoercedStore(llvm::Value *Src, llvm::Value *DstPtr, bool DstIsVolatile, CodeGenFunction &CGF) { const llvm::Type *SrcTy = Src->getType(); const llvm::Type *DstTy = cast(DstPtr->getType())->getElementType(); if (SrcTy == DstTy) { CGF.Builder.CreateStore(Src, DstPtr, DstIsVolatile); return; } uint64_t SrcSize = CGF.CGM.getTargetData().getTypeAllocSize(SrcTy); if (const llvm::StructType *DstSTy = dyn_cast(DstTy)) { DstPtr = EnterStructPointerForCoercedAccess(DstPtr, DstSTy, SrcSize, CGF); DstTy = cast(DstPtr->getType())->getElementType(); } // If the source and destination are integer or pointer types, just do an // extension or truncation to the desired type. if ((isa(SrcTy) || isa(SrcTy)) && (isa(DstTy) || isa(DstTy))) { Src = CoerceIntOrPtrToIntOrPtr(Src, DstTy, CGF); CGF.Builder.CreateStore(Src, DstPtr, DstIsVolatile); return; } uint64_t DstSize = CGF.CGM.getTargetData().getTypeAllocSize(DstTy); // If store is legal, just bitcast the src pointer. if (SrcSize <= DstSize) { llvm::Value *Casted = CGF.Builder.CreateBitCast(DstPtr, llvm::PointerType::getUnqual(SrcTy)); // FIXME: Use better alignment / avoid requiring aligned store. CGF.Builder.CreateStore(Src, Casted, DstIsVolatile)->setAlignment(1); } else { // Otherwise do coercion through memory. This is stupid, but // simple. // Generally SrcSize is never greater than DstSize, since this means we are // losing bits. However, this can happen in cases where the structure has // additional padding, for example due to a user specified alignment. // // FIXME: Assert that we aren't truncating non-padding bits when have access // to that information. llvm::Value *Tmp = CGF.CreateTempAlloca(SrcTy); CGF.Builder.CreateStore(Src, Tmp); llvm::Value *Casted = CGF.Builder.CreateBitCast(Tmp, llvm::PointerType::getUnqual(DstTy)); llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted); // FIXME: Use better alignment / avoid requiring aligned load. Load->setAlignment(1); CGF.Builder.CreateStore(Load, DstPtr, DstIsVolatile); } } /***/ bool CodeGenModule::ReturnTypeUsesSRet(const CGFunctionInfo &FI) { return FI.getReturnInfo().isIndirect(); } bool CodeGenModule::ReturnTypeUsesFPRet(QualType ResultType) { if (const BuiltinType *BT = ResultType->getAs()) { switch (BT->getKind()) { default: return false; case BuiltinType::Float: return getContext().Target.useObjCFPRetForRealType(TargetInfo::Float); case BuiltinType::Double: return getContext().Target.useObjCFPRetForRealType(TargetInfo::Double); case BuiltinType::LongDouble: return getContext().Target.useObjCFPRetForRealType( TargetInfo::LongDouble); } } return false; } const llvm::FunctionType *CodeGenTypes::GetFunctionType(GlobalDecl GD) { const CGFunctionInfo &FI = getFunctionInfo(GD); // For definition purposes, don't consider a K&R function variadic. bool Variadic = false; if (const FunctionProtoType *FPT = cast(GD.getDecl())->getType()->getAs()) Variadic = FPT->isVariadic(); return GetFunctionType(FI, Variadic, false); } const llvm::FunctionType * CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI, bool IsVariadic, bool IsRecursive) { std::vector ArgTys; const llvm::Type *ResultType = 0; QualType RetTy = FI.getReturnType(); const ABIArgInfo &RetAI = FI.getReturnInfo(); switch (RetAI.getKind()) { case ABIArgInfo::Expand: assert(0 && "Invalid ABI kind for return argument"); case ABIArgInfo::Extend: case ABIArgInfo::Direct: ResultType = ConvertType(RetTy, IsRecursive); break; case ABIArgInfo::Indirect: { assert(!RetAI.getIndirectAlign() && "Align unused on indirect return."); ResultType = llvm::Type::getVoidTy(getLLVMContext()); const llvm::Type *STy = ConvertType(RetTy, IsRecursive); ArgTys.push_back(llvm::PointerType::get(STy, RetTy.getAddressSpace())); break; } case ABIArgInfo::Ignore: ResultType = llvm::Type::getVoidTy(getLLVMContext()); break; case ABIArgInfo::Coerce: ResultType = RetAI.getCoerceToType(); break; } for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(), ie = FI.arg_end(); it != ie; ++it) { const ABIArgInfo &AI = it->info; switch (AI.getKind()) { case ABIArgInfo::Ignore: break; case ABIArgInfo::Coerce: { // If the coerce-to type is a first class aggregate, flatten it. Either // way is semantically identical, but fast-isel and the optimizer // generally likes scalar values better than FCAs. const llvm::Type *ArgTy = AI.getCoerceToType(); if (const llvm::StructType *STy = dyn_cast(ArgTy)) { for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) ArgTys.push_back(STy->getElementType(i)); } else { ArgTys.push_back(ArgTy); } break; } case ABIArgInfo::Indirect: { // indirect arguments are always on the stack, which is addr space #0. const llvm::Type *LTy = ConvertTypeForMem(it->type, IsRecursive); ArgTys.push_back(llvm::PointerType::getUnqual(LTy)); break; } case ABIArgInfo::Extend: case ABIArgInfo::Direct: ArgTys.push_back(ConvertType(it->type, IsRecursive)); break; case ABIArgInfo::Expand: GetExpandedTypes(it->type, ArgTys, IsRecursive); break; } } return llvm::FunctionType::get(ResultType, ArgTys, IsVariadic); } const llvm::Type * CodeGenTypes::GetFunctionTypeForVTable(const CXXMethodDecl *MD) { const FunctionProtoType *FPT = MD->getType()->getAs(); if (!VerifyFuncTypeComplete(FPT)) return GetFunctionType(getFunctionInfo(MD), FPT->isVariadic(), false); return llvm::OpaqueType::get(getLLVMContext()); } void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI, const Decl *TargetDecl, AttributeListType &PAL, unsigned &CallingConv) { unsigned FuncAttrs = 0; unsigned RetAttrs = 0; CallingConv = FI.getEffectiveCallingConvention(); if (FI.isNoReturn()) FuncAttrs |= llvm::Attribute::NoReturn; // FIXME: handle sseregparm someday... if (TargetDecl) { if (TargetDecl->hasAttr()) FuncAttrs |= llvm::Attribute::NoUnwind; else if (const FunctionDecl *Fn = dyn_cast(TargetDecl)) { const FunctionProtoType *FPT = Fn->getType()->getAs(); if (FPT && FPT->hasEmptyExceptionSpec()) FuncAttrs |= llvm::Attribute::NoUnwind; } if (TargetDecl->hasAttr()) FuncAttrs |= llvm::Attribute::NoReturn; if (TargetDecl->hasAttr()) FuncAttrs |= llvm::Attribute::ReadNone; else if (TargetDecl->hasAttr()) FuncAttrs |= llvm::Attribute::ReadOnly; if (TargetDecl->hasAttr()) RetAttrs |= llvm::Attribute::NoAlias; } if (CodeGenOpts.OptimizeSize) FuncAttrs |= llvm::Attribute::OptimizeForSize; if (CodeGenOpts.DisableRedZone) FuncAttrs |= llvm::Attribute::NoRedZone; if (CodeGenOpts.NoImplicitFloat) FuncAttrs |= llvm::Attribute::NoImplicitFloat; QualType RetTy = FI.getReturnType(); unsigned Index = 1; const ABIArgInfo &RetAI = FI.getReturnInfo(); switch (RetAI.getKind()) { case ABIArgInfo::Extend: if (RetTy->isSignedIntegerType()) { RetAttrs |= llvm::Attribute::SExt; } else if (RetTy->isUnsignedIntegerType()) { RetAttrs |= llvm::Attribute::ZExt; } // FALLTHROUGH case ABIArgInfo::Direct: break; case ABIArgInfo::Indirect: PAL.push_back(llvm::AttributeWithIndex::get(Index, llvm::Attribute::StructRet)); ++Index; // sret disables readnone and readonly FuncAttrs &= ~(llvm::Attribute::ReadOnly | llvm::Attribute::ReadNone); break; case ABIArgInfo::Ignore: case ABIArgInfo::Coerce: break; case ABIArgInfo::Expand: assert(0 && "Invalid ABI kind for return argument"); } if (RetAttrs) PAL.push_back(llvm::AttributeWithIndex::get(0, RetAttrs)); // FIXME: we need to honour command line settings also... // FIXME: RegParm should be reduced in case of nested functions and/or global // register variable. signed RegParm = FI.getRegParm(); unsigned PointerWidth = getContext().Target.getPointerWidth(0); for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(), ie = FI.arg_end(); it != ie; ++it) { QualType ParamType = it->type; const ABIArgInfo &AI = it->info; unsigned Attributes = 0; // '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 fucked up. switch (AI.getKind()) { case ABIArgInfo::Coerce: if (const llvm::StructType *STy = dyn_cast(AI.getCoerceToType())) Index += STy->getNumElements(); else ++Index; continue; // Skip index increment. case ABIArgInfo::Indirect: if (AI.getIndirectByVal()) Attributes |= llvm::Attribute::ByVal; Attributes |= llvm::Attribute::constructAlignmentFromInt(AI.getIndirectAlign()); // byval disables readnone and readonly. FuncAttrs &= ~(llvm::Attribute::ReadOnly | llvm::Attribute::ReadNone); break; case ABIArgInfo::Extend: if (ParamType->isSignedIntegerType()) { Attributes |= llvm::Attribute::SExt; } else if (ParamType->isUnsignedIntegerType()) { Attributes |= llvm::Attribute::ZExt; } // FALLS THROUGH case ABIArgInfo::Direct: if (RegParm > 0 && (ParamType->isIntegerType() || ParamType->isPointerType())) { RegParm -= (Context.getTypeSize(ParamType) + PointerWidth - 1) / PointerWidth; if (RegParm >= 0) Attributes |= llvm::Attribute::InReg; } // FIXME: handle sseregparm someday... break; case ABIArgInfo::Ignore: // Skip increment, no matching LLVM parameter. continue; case ABIArgInfo::Expand: { std::vector Tys; // FIXME: This is rather inefficient. Do we ever actually need to do // anything here? The result should be just reconstructed on the other // side, so extension should be a non-issue. getTypes().GetExpandedTypes(ParamType, Tys, false); Index += Tys.size(); continue; } } if (Attributes) PAL.push_back(llvm::AttributeWithIndex::get(Index, Attributes)); ++Index; } if (FuncAttrs) PAL.push_back(llvm::AttributeWithIndex::get(~0, FuncAttrs)); } void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI, llvm::Function *Fn, const FunctionArgList &Args) { // If this is an implicit-return-zero function, go ahead and // initialize the return value. TODO: it might be nice to have // a more general mechanism for this that didn't require synthesized // return statements. if (const FunctionDecl *FD = dyn_cast_or_null(CurFuncDecl)) { if (FD->hasImplicitReturnZero()) { QualType RetTy = FD->getResultType().getUnqualifiedType(); const llvm::Type* LLVMTy = CGM.getTypes().ConvertType(RetTy); llvm::Constant* Zero = llvm::Constant::getNullValue(LLVMTy); Builder.CreateStore(Zero, ReturnValue); } } // FIXME: We no longer need the types from FunctionArgList; lift up and // simplify. // Emit allocs for param decls. Give the LLVM Argument nodes names. llvm::Function::arg_iterator AI = Fn->arg_begin(); // Name the struct return argument. if (CGM.ReturnTypeUsesSRet(FI)) { AI->setName("agg.result"); ++AI; } assert(FI.arg_size() == Args.size() && "Mismatch between function signature & arguments."); CGFunctionInfo::const_arg_iterator info_it = FI.arg_begin(); for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end(); i != e; ++i, ++info_it) { const VarDecl *Arg = i->first; QualType Ty = info_it->type; const ABIArgInfo &ArgI = info_it->info; switch (ArgI.getKind()) { case ABIArgInfo::Indirect: { llvm::Value *V = AI; if (hasAggregateLLVMType(Ty)) { // Do nothing, aggregates and complex variables are accessed by // reference. } else { // Load scalar value from indirect argument. V = EmitLoadOfScalar(V, false, Ty); if (!getContext().typesAreCompatible(Ty, Arg->getType())) { // This must be a promotion, for something like // "void a(x) short x; {..." V = EmitScalarConversion(V, Ty, Arg->getType()); } } EmitParmDecl(*Arg, V); break; } case ABIArgInfo::Extend: case ABIArgInfo::Direct: { assert(AI != Fn->arg_end() && "Argument mismatch!"); llvm::Value *V = AI; if (hasAggregateLLVMType(Ty)) { // Create a temporary alloca to hold the argument; the rest of // codegen expects to access aggregates & complex values by // reference. V = CreateMemTemp(Ty); Builder.CreateStore(AI, V); } else { if (Arg->getType().isRestrictQualified()) AI->addAttr(llvm::Attribute::NoAlias); if (!getContext().typesAreCompatible(Ty, Arg->getType())) { // This must be a promotion, for something like // "void a(x) short x; {..." V = EmitScalarConversion(V, Ty, Arg->getType()); } } EmitParmDecl(*Arg, V); 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. llvm::Value *Temp = CreateMemTemp(Ty, Arg->getName() + ".addr"); // FIXME: What are the right qualifiers here? llvm::Function::arg_iterator End = ExpandTypeFromArgs(Ty, LValue::MakeAddr(Temp, Qualifiers()), AI); EmitParmDecl(*Arg, Temp); // Name the arguments used in expansion and increment AI. unsigned Index = 0; for (; AI != End; ++AI, ++Index) AI->setName(Arg->getName() + "." + llvm::Twine(Index)); continue; } case ABIArgInfo::Ignore: // Initialize the local variable appropriately. if (hasAggregateLLVMType(Ty)) { EmitParmDecl(*Arg, CreateMemTemp(Ty)); } else { EmitParmDecl(*Arg, llvm::UndefValue::get(ConvertType(Arg->getType()))); } // Skip increment, no matching LLVM parameter. continue; case ABIArgInfo::Coerce: { // FIXME: This is very wasteful; EmitParmDecl is just going to drop the // result in a new alloca anyway, so we could just store into that // directly if we broke the abstraction down more. llvm::AllocaInst *Alloca = CreateMemTemp(Ty, "coerce"); Alloca->setAlignment(getContext().getDeclAlign(Arg).getQuantity()); llvm::Value *V = Alloca; // If the coerce-to type is a first class aggregate, we flatten it and // pass the elements. Either way is semantically identical, but fast-isel // and the optimizer generally likes scalar values better than FCAs. if (const llvm::StructType *STy = dyn_cast(ArgI.getCoerceToType())) { llvm::Value *Ptr = V; Ptr = Builder.CreateBitCast(Ptr, llvm::PointerType::getUnqual(STy)); for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { assert(AI != Fn->arg_end() && "Argument mismatch!"); AI->setName(Arg->getName() + ".coerce" + llvm::Twine(i)); llvm::Value *EltPtr = Builder.CreateConstGEP2_32(Ptr, 0, i); Builder.CreateStore(AI++, EltPtr); } } else { // Simple case, just do a coerced store of the argument into the alloca. assert(AI != Fn->arg_end() && "Argument mismatch!"); AI->setName(Arg->getName() + ".coerce"); CreateCoercedStore(AI++, V, /*DestIsVolatile=*/false, *this); } // Match to what EmitParmDecl is expecting for this type. if (!CodeGenFunction::hasAggregateLLVMType(Ty)) { V = EmitLoadOfScalar(V, false, Ty); if (!getContext().typesAreCompatible(Ty, Arg->getType())) { // This must be a promotion, for something like // "void a(x) short x; {..." V = EmitScalarConversion(V, Ty, Arg->getType()); } } EmitParmDecl(*Arg, V); continue; // Skip ++AI increment, already done. } } ++AI; } assert(AI == Fn->arg_end() && "Argument mismatch!"); } void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI) { // Functions with no result always return void. if (ReturnValue == 0) { Builder.CreateRetVoid(); return; } llvm::MDNode *RetDbgInfo = 0; llvm::Value *RV = 0; QualType RetTy = FI.getReturnType(); const ABIArgInfo &RetAI = FI.getReturnInfo(); switch (RetAI.getKind()) { case ABIArgInfo::Indirect: if (RetTy->isAnyComplexType()) { ComplexPairTy RT = LoadComplexFromAddr(ReturnValue, false); StoreComplexToAddr(RT, CurFn->arg_begin(), false); } else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) { // Do nothing; aggregrates get evaluated directly into the destination. } else { EmitStoreOfScalar(Builder.CreateLoad(ReturnValue), CurFn->arg_begin(), false, RetTy); } break; case ABIArgInfo::Extend: case ABIArgInfo::Direct: { // The internal return value temp always will have pointer-to-return-type // type, just do a load. // If the instruction right before the insertion point is a store to the // return value, we can elide the load, zap the store, and usually zap the // alloca. llvm::BasicBlock *InsertBB = Builder.GetInsertBlock(); llvm::StoreInst *SI = 0; if (InsertBB->empty() || !(SI = dyn_cast(&InsertBB->back())) || SI->getPointerOperand() != ReturnValue || SI->isVolatile()) { RV = Builder.CreateLoad(ReturnValue); } else { // Get the stored value and nuke the now-dead store. RetDbgInfo = SI->getDbgMetadata(); RV = SI->getValueOperand(); SI->eraseFromParent(); // If that was the only use of the return value, nuke it as well now. if (ReturnValue->use_empty() && isa(ReturnValue)) { cast(ReturnValue)->eraseFromParent(); ReturnValue = 0; } } break; } case ABIArgInfo::Ignore: break; case ABIArgInfo::Coerce: RV = CreateCoercedLoad(ReturnValue, RetAI.getCoerceToType(), *this); break; case ABIArgInfo::Expand: assert(0 && "Invalid ABI kind for return argument"); } llvm::Instruction *Ret = RV ? Builder.CreateRet(RV) : Builder.CreateRetVoid(); if (RetDbgInfo) Ret->setDbgMetadata(RetDbgInfo); } RValue CodeGenFunction::EmitDelegateCallArg(const VarDecl *Param) { // StartFunction converted the ABI-lowered parameter(s) into a // local alloca. We need to turn that into an r-value suitable // for EmitCall. llvm::Value *Local = GetAddrOfLocalVar(Param); QualType ArgType = 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 aggregates are pointers directly to the aggregate. // I don't know why references to non-aggregates are different here. if (const ReferenceType *RefType = ArgType->getAs()) { if (hasAggregateLLVMType(RefType->getPointeeType())) return RValue::getAggregate(Local); // Locals which are references to scalars are represented // with allocas holding the pointer. return RValue::get(Builder.CreateLoad(Local)); } if (ArgType->isAnyComplexType()) return RValue::getComplex(LoadComplexFromAddr(Local, /*volatile*/ false)); if (hasAggregateLLVMType(ArgType)) return RValue::getAggregate(Local); return RValue::get(EmitLoadOfScalar(Local, false, ArgType)); } RValue CodeGenFunction::EmitCallArg(const Expr *E, QualType ArgType) { if (ArgType->isReferenceType()) return EmitReferenceBindingToExpr(E, /*InitializedDecl=*/0); return EmitAnyExprToTemp(E); } /// 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, llvm::Value * const *ArgBegin, llvm::Value * const *ArgEnd, const llvm::Twine &Name) { llvm::BasicBlock *InvokeDest = getInvokeDest(); if (!InvokeDest) return Builder.CreateCall(Callee, ArgBegin, ArgEnd, Name); llvm::BasicBlock *ContBB = createBasicBlock("invoke.cont"); llvm::InvokeInst *Invoke = Builder.CreateInvoke(Callee, ContBB, InvokeDest, ArgBegin, ArgEnd, Name); EmitBlock(ContBB); return Invoke; } RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo, llvm::Value *Callee, ReturnValueSlot ReturnValue, const CallArgList &CallArgs, const Decl *TargetDecl, llvm::Instruction **callOrInvoke) { // FIXME: We no longer need the types from CallArgs; lift up and simplify. llvm::SmallVector Args; // Handle struct-return functions by passing a pointer to the // location that we would like to return into. QualType RetTy = CallInfo.getReturnType(); const ABIArgInfo &RetAI = CallInfo.getReturnInfo(); // If the call returns a temporary with struct return, create a temporary // alloca to hold the result, unless one is given to us. if (CGM.ReturnTypeUsesSRet(CallInfo)) { llvm::Value *Value = ReturnValue.getValue(); if (!Value) Value = CreateMemTemp(RetTy); Args.push_back(Value); } assert(CallInfo.arg_size() == CallArgs.size() && "Mismatch between function signature & arguments."); CGFunctionInfo::const_arg_iterator info_it = CallInfo.arg_begin(); for (CallArgList::const_iterator I = CallArgs.begin(), E = CallArgs.end(); I != E; ++I, ++info_it) { const ABIArgInfo &ArgInfo = info_it->info; RValue RV = I->first; switch (ArgInfo.getKind()) { case ABIArgInfo::Indirect: if (RV.isScalar() || RV.isComplex()) { // Make a temporary alloca to pass the argument. Args.push_back(CreateMemTemp(I->second)); if (RV.isScalar()) EmitStoreOfScalar(RV.getScalarVal(), Args.back(), false, I->second); else StoreComplexToAddr(RV.getComplexVal(), Args.back(), false); } else { Args.push_back(RV.getAggregateAddr()); } break; case ABIArgInfo::Extend: case ABIArgInfo::Direct: if (RV.isScalar()) { Args.push_back(RV.getScalarVal()); } else if (RV.isComplex()) { llvm::Value *Tmp = llvm::UndefValue::get(ConvertType(I->second)); Tmp = Builder.CreateInsertValue(Tmp, RV.getComplexVal().first, 0); Tmp = Builder.CreateInsertValue(Tmp, RV.getComplexVal().second, 1); Args.push_back(Tmp); } else { Args.push_back(Builder.CreateLoad(RV.getAggregateAddr())); } break; case ABIArgInfo::Ignore: break; case ABIArgInfo::Coerce: { // FIXME: Avoid the conversion through memory if possible. llvm::Value *SrcPtr; if (RV.isScalar()) { SrcPtr = CreateMemTemp(I->second, "coerce"); EmitStoreOfScalar(RV.getScalarVal(), SrcPtr, false, I->second); } else if (RV.isComplex()) { SrcPtr = CreateMemTemp(I->second, "coerce"); StoreComplexToAddr(RV.getComplexVal(), SrcPtr, false); } else SrcPtr = RV.getAggregateAddr(); // If the coerce-to type is a first class aggregate, we flatten it and // pass the elements. Either way is semantically identical, but fast-isel // and the optimizer generally likes scalar values better than FCAs. if (const llvm::StructType *STy = dyn_cast(ArgInfo.getCoerceToType())) { SrcPtr = Builder.CreateBitCast(SrcPtr, llvm::PointerType::getUnqual(STy)); for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { llvm::Value *EltPtr = Builder.CreateConstGEP2_32(SrcPtr, 0, i); Args.push_back(Builder.CreateLoad(EltPtr)); } } else { // In the simple case, just pass the coerced loaded value. Args.push_back(CreateCoercedLoad(SrcPtr, ArgInfo.getCoerceToType(), *this)); } break; } case ABIArgInfo::Expand: ExpandTypeToArgs(I->second, RV, Args); break; } } // If the callee is a bitcast of a function to a varargs pointer to function // type, check to see if we can remove the bitcast. This handles some cases // with unprototyped functions. if (llvm::ConstantExpr *CE = dyn_cast(Callee)) if (llvm::Function *CalleeF = dyn_cast(CE->getOperand(0))) { const llvm::PointerType *CurPT=cast(Callee->getType()); const llvm::FunctionType *CurFT = cast(CurPT->getElementType()); const llvm::FunctionType *ActualFT = CalleeF->getFunctionType(); if (CE->getOpcode() == llvm::Instruction::BitCast && ActualFT->getReturnType() == CurFT->getReturnType() && ActualFT->getNumParams() == CurFT->getNumParams() && ActualFT->getNumParams() == Args.size()) { bool ArgsMatch = true; for (unsigned i = 0, e = ActualFT->getNumParams(); i != e; ++i) if (ActualFT->getParamType(i) != CurFT->getParamType(i)) { ArgsMatch = false; break; } // Strip the cast if we can get away with it. This is a nice cleanup, // but also allows us to inline the function at -O0 if it is marked // always_inline. if (ArgsMatch) Callee = CalleeF; } } unsigned CallingConv; CodeGen::AttributeListType AttributeList; CGM.ConstructAttributeList(CallInfo, TargetDecl, AttributeList, CallingConv); llvm::AttrListPtr Attrs = llvm::AttrListPtr::get(AttributeList.begin(), AttributeList.end()); llvm::BasicBlock *InvokeDest = 0; if (!(Attrs.getFnAttributes() & llvm::Attribute::NoUnwind)) InvokeDest = getInvokeDest(); llvm::CallSite CS; if (!InvokeDest) { CS = Builder.CreateCall(Callee, Args.data(), Args.data()+Args.size()); } else { llvm::BasicBlock *Cont = createBasicBlock("invoke.cont"); CS = Builder.CreateInvoke(Callee, Cont, InvokeDest, Args.data(), Args.data()+Args.size()); EmitBlock(Cont); } if (callOrInvoke) *callOrInvoke = CS.getInstruction(); CS.setAttributes(Attrs); CS.setCallingConv(static_cast(CallingConv)); // If the call doesn't return, finish the basic block and clear the // insertion point; this allows the rest of IRgen to discard // unreachable code. if (CS.doesNotReturn()) { Builder.CreateUnreachable(); Builder.ClearInsertionPoint(); // FIXME: For now, emit a dummy basic block because expr emitters in // generally are not ready to handle emitting expressions at unreachable // points. EnsureInsertPoint(); // Return a reasonable RValue. return GetUndefRValue(RetTy); } llvm::Instruction *CI = CS.getInstruction(); if (Builder.isNamePreserving() && !CI->getType()->isVoidTy()) CI->setName("call"); switch (RetAI.getKind()) { case ABIArgInfo::Indirect: if (RetTy->isAnyComplexType()) return RValue::getComplex(LoadComplexFromAddr(Args[0], false)); if (CodeGenFunction::hasAggregateLLVMType(RetTy)) return RValue::getAggregate(Args[0]); return RValue::get(EmitLoadOfScalar(Args[0], false, RetTy)); case ABIArgInfo::Extend: case ABIArgInfo::Direct: if (RetTy->isAnyComplexType()) { llvm::Value *Real = Builder.CreateExtractValue(CI, 0); llvm::Value *Imag = Builder.CreateExtractValue(CI, 1); return RValue::getComplex(std::make_pair(Real, Imag)); } if (CodeGenFunction::hasAggregateLLVMType(RetTy)) { llvm::Value *DestPtr = ReturnValue.getValue(); bool DestIsVolatile = ReturnValue.isVolatile(); if (!DestPtr) { DestPtr = CreateMemTemp(RetTy, "agg.tmp"); DestIsVolatile = false; } Builder.CreateStore(CI, DestPtr, DestIsVolatile); return RValue::getAggregate(DestPtr); } return RValue::get(CI); 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::Coerce: { llvm::Value *DestPtr = ReturnValue.getValue(); bool DestIsVolatile = ReturnValue.isVolatile(); if (!DestPtr) { DestPtr = CreateMemTemp(RetTy, "coerce"); DestIsVolatile = false; } CreateCoercedStore(CI, DestPtr, DestIsVolatile, *this); if (RetTy->isAnyComplexType()) return RValue::getComplex(LoadComplexFromAddr(DestPtr, false)); if (CodeGenFunction::hasAggregateLLVMType(RetTy)) return RValue::getAggregate(DestPtr); return RValue::get(EmitLoadOfScalar(DestPtr, false, RetTy)); } case ABIArgInfo::Expand: assert(0 && "Invalid ABI kind for return argument"); } assert(0 && "Unhandled ABIArgInfo::Kind"); return RValue::get(0); } /* VarArg handling */ llvm::Value *CodeGenFunction::EmitVAArg(llvm::Value *VAListAddr, QualType Ty) { return CGM.getTypes().getABIInfo().EmitVAArg(VAListAddr, Ty, *this); }