//===--- CodeGenTypes.cpp - Type translation for LLVM CodeGen -------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This is the code that handles AST -> LLVM type lowering. // //===----------------------------------------------------------------------===// #include "CodeGenTypes.h" #include "CGCXXABI.h" #include "CGCall.h" #include "CGOpenCLRuntime.h" #include "CGRecordLayout.h" #include "TargetInfo.h" #include "clang/AST/ASTContext.h" #include "clang/AST/DeclCXX.h" #include "clang/AST/DeclObjC.h" #include "clang/AST/Expr.h" #include "clang/AST/RecordLayout.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/DerivedTypes.h" #include "llvm/IR/Module.h" using namespace clang; using namespace CodeGen; CodeGenTypes::CodeGenTypes(CodeGenModule &cgm) : CGM(cgm), Context(cgm.getContext()), TheModule(cgm.getModule()), TheDataLayout(cgm.getDataLayout()), Target(cgm.getTarget()), TheCXXABI(cgm.getCXXABI()), CodeGenOpts(cgm.getCodeGenOpts()), TheABIInfo(cgm.getTargetCodeGenInfo().getABIInfo()) { SkippedLayout = false; } CodeGenTypes::~CodeGenTypes() { for (llvm::DenseMap::iterator I = CGRecordLayouts.begin(), E = CGRecordLayouts.end(); I != E; ++I) delete I->second; for (llvm::FoldingSet::iterator I = FunctionInfos.begin(), E = FunctionInfos.end(); I != E; ) delete &*I++; } void CodeGenTypes::addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty, StringRef suffix) { SmallString<256> TypeName; llvm::raw_svector_ostream OS(TypeName); OS << RD->getKindName() << '.'; // Name the codegen type after the typedef name // if there is no tag type name available if (RD->getIdentifier()) { // FIXME: We should not have to check for a null decl context here. // Right now we do it because the implicit Obj-C decls don't have one. if (RD->getDeclContext()) RD->printQualifiedName(OS); else RD->printName(OS); } else if (const TypedefNameDecl *TDD = RD->getTypedefNameForAnonDecl()) { // FIXME: We should not have to check for a null decl context here. // Right now we do it because the implicit Obj-C decls don't have one. if (TDD->getDeclContext()) TDD->printQualifiedName(OS); else TDD->printName(OS); } else OS << "anon"; if (!suffix.empty()) OS << suffix; Ty->setName(OS.str()); } /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from /// ConvertType in that it is used to convert to the memory representation for /// a type. For example, the scalar representation for _Bool is i1, but the /// memory representation is usually i8 or i32, depending on the target. llvm::Type *CodeGenTypes::ConvertTypeForMem(QualType T){ llvm::Type *R = ConvertType(T); // If this is a non-bool type, don't map it. if (!R->isIntegerTy(1)) return R; // Otherwise, return an integer of the target-specified size. return llvm::IntegerType::get(getLLVMContext(), (unsigned)Context.getTypeSize(T)); } /// isRecordLayoutComplete - Return true if the specified type is already /// completely laid out. bool CodeGenTypes::isRecordLayoutComplete(const Type *Ty) const { llvm::DenseMap::const_iterator I = RecordDeclTypes.find(Ty); return I != RecordDeclTypes.end() && !I->second->isOpaque(); } static bool isSafeToConvert(QualType T, CodeGenTypes &CGT, llvm::SmallPtrSet &AlreadyChecked); /// isSafeToConvert - Return true if it is safe to convert the specified record /// decl to IR and lay it out, false if doing so would cause us to get into a /// recursive compilation mess. static bool isSafeToConvert(const RecordDecl *RD, CodeGenTypes &CGT, llvm::SmallPtrSet &AlreadyChecked) { // If we have already checked this type (maybe the same type is used by-value // multiple times in multiple structure fields, don't check again. if (!AlreadyChecked.insert(RD)) return true; const Type *Key = CGT.getContext().getTagDeclType(RD).getTypePtr(); // If this type is already laid out, converting it is a noop. if (CGT.isRecordLayoutComplete(Key)) return true; // If this type is currently being laid out, we can't recursively compile it. if (CGT.isRecordBeingLaidOut(Key)) return false; // If this type would require laying out bases that are currently being laid // out, don't do it. This includes virtual base classes which get laid out // when a class is translated, even though they aren't embedded by-value into // the class. if (const CXXRecordDecl *CRD = dyn_cast(RD)) { for (CXXRecordDecl::base_class_const_iterator I = CRD->bases_begin(), E = CRD->bases_end(); I != E; ++I) if (!isSafeToConvert(I->getType()->getAs()->getDecl(), CGT, AlreadyChecked)) return false; } // If this type would require laying out members that are currently being laid // out, don't do it. for (RecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end(); I != E; ++I) if (!isSafeToConvert(I->getType(), CGT, AlreadyChecked)) return false; // If there are no problems, lets do it. return true; } /// isSafeToConvert - Return true if it is safe to convert this field type, /// which requires the structure elements contained by-value to all be /// recursively safe to convert. static bool isSafeToConvert(QualType T, CodeGenTypes &CGT, llvm::SmallPtrSet &AlreadyChecked) { T = T.getCanonicalType(); // If this is a record, check it. if (const RecordType *RT = dyn_cast(T)) return isSafeToConvert(RT->getDecl(), CGT, AlreadyChecked); // If this is an array, check the elements, which are embedded inline. if (const ArrayType *AT = dyn_cast(T)) return isSafeToConvert(AT->getElementType(), CGT, AlreadyChecked); // Otherwise, there is no concern about transforming this. We only care about // things that are contained by-value in a structure that can have another // structure as a member. return true; } /// isSafeToConvert - Return true if it is safe to convert the specified record /// decl to IR and lay it out, false if doing so would cause us to get into a /// recursive compilation mess. static bool isSafeToConvert(const RecordDecl *RD, CodeGenTypes &CGT) { // If no structs are being laid out, we can certainly do this one. if (CGT.noRecordsBeingLaidOut()) return true; llvm::SmallPtrSet AlreadyChecked; return isSafeToConvert(RD, CGT, AlreadyChecked); } /// isFuncTypeArgumentConvertible - Return true if the specified type in a /// function argument or result position can be converted to an IR type at this /// point. This boils down to being whether it is complete, as well as whether /// we've temporarily deferred expanding the type because we're in a recursive /// context. bool CodeGenTypes::isFuncTypeArgumentConvertible(QualType Ty) { // If this isn't a tagged type, we can convert it! const TagType *TT = Ty->getAs(); if (TT == 0) return true; // Incomplete types cannot be converted. if (TT->isIncompleteType()) return false; // If this is an enum, then it is always safe to convert. const RecordType *RT = dyn_cast(TT); if (RT == 0) return true; // Otherwise, we have to be careful. If it is a struct that we're in the // process of expanding, then we can't convert the function type. That's ok // though because we must be in a pointer context under the struct, so we can // just convert it to a dummy type. // // We decide this by checking whether ConvertRecordDeclType returns us an // opaque type for a struct that we know is defined. return isSafeToConvert(RT->getDecl(), *this); } /// Code to verify a given function type is complete, i.e. the return type /// and all of the argument types are complete. Also check to see if we are in /// a RS_StructPointer context, and if so whether any struct types have been /// pended. If so, we don't want to ask the ABI lowering code to handle a type /// that cannot be converted to an IR type. bool CodeGenTypes::isFuncTypeConvertible(const FunctionType *FT) { if (!isFuncTypeArgumentConvertible(FT->getResultType())) return false; if (const FunctionProtoType *FPT = dyn_cast(FT)) for (unsigned i = 0, e = FPT->getNumArgs(); i != e; i++) if (!isFuncTypeArgumentConvertible(FPT->getArgType(i))) return false; return true; } /// UpdateCompletedType - When we find the full definition for a TagDecl, /// replace the 'opaque' type we previously made for it if applicable. void CodeGenTypes::UpdateCompletedType(const TagDecl *TD) { // If this is an enum being completed, then we flush all non-struct types from // the cache. This allows function types and other things that may be derived // from the enum to be recomputed. if (const EnumDecl *ED = dyn_cast(TD)) { // Only flush the cache if we've actually already converted this type. if (TypeCache.count(ED->getTypeForDecl())) { // Okay, we formed some types based on this. We speculated that the enum // would be lowered to i32, so we only need to flush the cache if this // didn't happen. if (!ConvertType(ED->getIntegerType())->isIntegerTy(32)) TypeCache.clear(); } return; } // If we completed a RecordDecl that we previously used and converted to an // anonymous type, then go ahead and complete it now. const RecordDecl *RD = cast(TD); if (RD->isDependentType()) return; // Only complete it if we converted it already. If we haven't converted it // yet, we'll just do it lazily. if (RecordDeclTypes.count(Context.getTagDeclType(RD).getTypePtr())) ConvertRecordDeclType(RD); } static llvm::Type *getTypeForFormat(llvm::LLVMContext &VMContext, const llvm::fltSemantics &format, bool UseNativeHalf = false) { if (&format == &llvm::APFloat::IEEEhalf) { if (UseNativeHalf) return llvm::Type::getHalfTy(VMContext); else return llvm::Type::getInt16Ty(VMContext); } if (&format == &llvm::APFloat::IEEEsingle) return llvm::Type::getFloatTy(VMContext); if (&format == &llvm::APFloat::IEEEdouble) return llvm::Type::getDoubleTy(VMContext); if (&format == &llvm::APFloat::IEEEquad) return llvm::Type::getFP128Ty(VMContext); if (&format == &llvm::APFloat::PPCDoubleDouble) return llvm::Type::getPPC_FP128Ty(VMContext); if (&format == &llvm::APFloat::x87DoubleExtended) return llvm::Type::getX86_FP80Ty(VMContext); llvm_unreachable("Unknown float format!"); } /// ConvertType - Convert the specified type to its LLVM form. llvm::Type *CodeGenTypes::ConvertType(QualType T) { T = Context.getCanonicalType(T); const Type *Ty = T.getTypePtr(); // RecordTypes are cached and processed specially. if (const RecordType *RT = dyn_cast(Ty)) return ConvertRecordDeclType(RT->getDecl()); // See if type is already cached. llvm::DenseMap::iterator TCI = TypeCache.find(Ty); // If type is found in map then use it. Otherwise, convert type T. if (TCI != TypeCache.end()) return TCI->second; // If we don't have it in the cache, convert it now. llvm::Type *ResultType = 0; switch (Ty->getTypeClass()) { case Type::Record: // Handled above. #define TYPE(Class, Base) #define ABSTRACT_TYPE(Class, Base) #define NON_CANONICAL_TYPE(Class, Base) case Type::Class: #define DEPENDENT_TYPE(Class, Base) case Type::Class: #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class: #include "clang/AST/TypeNodes.def" llvm_unreachable("Non-canonical or dependent types aren't possible."); case Type::Builtin: { switch (cast(Ty)->getKind()) { case BuiltinType::Void: case BuiltinType::ObjCId: case BuiltinType::ObjCClass: case BuiltinType::ObjCSel: // LLVM void type can only be used as the result of a function call. Just // map to the same as char. ResultType = llvm::Type::getInt8Ty(getLLVMContext()); break; case BuiltinType::Bool: // Note that we always return bool as i1 for use as a scalar type. ResultType = llvm::Type::getInt1Ty(getLLVMContext()); break; case BuiltinType::Char_S: case BuiltinType::Char_U: case BuiltinType::SChar: case BuiltinType::UChar: case BuiltinType::Short: case BuiltinType::UShort: case BuiltinType::Int: case BuiltinType::UInt: case BuiltinType::Long: case BuiltinType::ULong: case BuiltinType::LongLong: case BuiltinType::ULongLong: case BuiltinType::WChar_S: case BuiltinType::WChar_U: case BuiltinType::Char16: case BuiltinType::Char32: ResultType = llvm::IntegerType::get(getLLVMContext(), static_cast(Context.getTypeSize(T))); break; case BuiltinType::Half: // Half FP can either be storage-only (lowered to i16) or native. ResultType = getTypeForFormat(getLLVMContext(), Context.getFloatTypeSemantics(T), Context.getLangOpts().NativeHalfType); break; case BuiltinType::Float: case BuiltinType::Double: case BuiltinType::LongDouble: ResultType = getTypeForFormat(getLLVMContext(), Context.getFloatTypeSemantics(T), /* UseNativeHalf = */ false); break; case BuiltinType::NullPtr: // Model std::nullptr_t as i8* ResultType = llvm::Type::getInt8PtrTy(getLLVMContext()); break; case BuiltinType::UInt128: case BuiltinType::Int128: ResultType = llvm::IntegerType::get(getLLVMContext(), 128); break; case BuiltinType::OCLImage1d: case BuiltinType::OCLImage1dArray: case BuiltinType::OCLImage1dBuffer: case BuiltinType::OCLImage2d: case BuiltinType::OCLImage2dArray: case BuiltinType::OCLImage3d: case BuiltinType::OCLSampler: case BuiltinType::OCLEvent: ResultType = CGM.getOpenCLRuntime().convertOpenCLSpecificType(Ty); break; case BuiltinType::Dependent: #define BUILTIN_TYPE(Id, SingletonId) #define PLACEHOLDER_TYPE(Id, SingletonId) \ case BuiltinType::Id: #include "clang/AST/BuiltinTypes.def" llvm_unreachable("Unexpected placeholder builtin type!"); } break; } case Type::Auto: llvm_unreachable("Unexpected undeduced auto type!"); case Type::Complex: { llvm::Type *EltTy = ConvertType(cast(Ty)->getElementType()); ResultType = llvm::StructType::get(EltTy, EltTy, NULL); break; } case Type::LValueReference: case Type::RValueReference: { const ReferenceType *RTy = cast(Ty); QualType ETy = RTy->getPointeeType(); llvm::Type *PointeeType = ConvertTypeForMem(ETy); unsigned AS = Context.getTargetAddressSpace(ETy); ResultType = llvm::PointerType::get(PointeeType, AS); break; } case Type::Pointer: { const PointerType *PTy = cast(Ty); QualType ETy = PTy->getPointeeType(); llvm::Type *PointeeType = ConvertTypeForMem(ETy); if (PointeeType->isVoidTy()) PointeeType = llvm::Type::getInt8Ty(getLLVMContext()); unsigned AS = Context.getTargetAddressSpace(ETy); ResultType = llvm::PointerType::get(PointeeType, AS); break; } case Type::VariableArray: { const VariableArrayType *A = cast(Ty); assert(A->getIndexTypeCVRQualifiers() == 0 && "FIXME: We only handle trivial array types so far!"); // VLAs resolve to the innermost element type; this matches // the return of alloca, and there isn't any obviously better choice. ResultType = ConvertTypeForMem(A->getElementType()); break; } case Type::IncompleteArray: { const IncompleteArrayType *A = cast(Ty); assert(A->getIndexTypeCVRQualifiers() == 0 && "FIXME: We only handle trivial array types so far!"); // int X[] -> [0 x int], unless the element type is not sized. If it is // unsized (e.g. an incomplete struct) just use [0 x i8]. ResultType = ConvertTypeForMem(A->getElementType()); if (!ResultType->isSized()) { SkippedLayout = true; ResultType = llvm::Type::getInt8Ty(getLLVMContext()); } ResultType = llvm::ArrayType::get(ResultType, 0); break; } case Type::ConstantArray: { const ConstantArrayType *A = cast(Ty); llvm::Type *EltTy = ConvertTypeForMem(A->getElementType()); // Lower arrays of undefined struct type to arrays of i8 just to have a // concrete type. if (!EltTy->isSized()) { SkippedLayout = true; EltTy = llvm::Type::getInt8Ty(getLLVMContext()); } ResultType = llvm::ArrayType::get(EltTy, A->getSize().getZExtValue()); break; } case Type::ExtVector: case Type::Vector: { const VectorType *VT = cast(Ty); ResultType = llvm::VectorType::get(ConvertType(VT->getElementType()), VT->getNumElements()); break; } case Type::FunctionNoProto: case Type::FunctionProto: { const FunctionType *FT = cast(Ty); // First, check whether we can build the full function type. If the // function type depends on an incomplete type (e.g. a struct or enum), we // cannot lower the function type. if (!isFuncTypeConvertible(FT)) { // This function's type depends on an incomplete tag type. // Force conversion of all the relevant record types, to make sure // we re-convert the FunctionType when appropriate. if (const RecordType *RT = FT->getResultType()->getAs()) ConvertRecordDeclType(RT->getDecl()); if (const FunctionProtoType *FPT = dyn_cast(FT)) for (unsigned i = 0, e = FPT->getNumArgs(); i != e; i++) if (const RecordType *RT = FPT->getArgType(i)->getAs()) ConvertRecordDeclType(RT->getDecl()); // Return a placeholder type. ResultType = llvm::StructType::get(getLLVMContext()); SkippedLayout = true; break; } // While we're converting the argument types for a function, we don't want // to recursively convert any pointed-to structs. Converting directly-used // structs is ok though. if (!RecordsBeingLaidOut.insert(Ty)) { ResultType = llvm::StructType::get(getLLVMContext()); SkippedLayout = true; break; } // The function type can be built; call the appropriate routines to // build it. const CGFunctionInfo *FI; if (const FunctionProtoType *FPT = dyn_cast(FT)) { FI = &arrangeFreeFunctionType( CanQual::CreateUnsafe(QualType(FPT, 0))); } else { const FunctionNoProtoType *FNPT = cast(FT); FI = &arrangeFreeFunctionType( CanQual::CreateUnsafe(QualType(FNPT, 0))); } // If there is something higher level prodding our CGFunctionInfo, then // don't recurse into it again. if (FunctionsBeingProcessed.count(FI)) { ResultType = llvm::StructType::get(getLLVMContext()); SkippedLayout = true; } else { // Otherwise, we're good to go, go ahead and convert it. ResultType = GetFunctionType(*FI); } RecordsBeingLaidOut.erase(Ty); if (SkippedLayout) TypeCache.clear(); if (RecordsBeingLaidOut.empty()) while (!DeferredRecords.empty()) ConvertRecordDeclType(DeferredRecords.pop_back_val()); break; } case Type::ObjCObject: ResultType = ConvertType(cast(Ty)->getBaseType()); break; case Type::ObjCInterface: { // Objective-C interfaces are always opaque (outside of the // runtime, which can do whatever it likes); we never refine // these. llvm::Type *&T = InterfaceTypes[cast(Ty)]; if (!T) T = llvm::StructType::create(getLLVMContext()); ResultType = T; break; } case Type::ObjCObjectPointer: { // Protocol qualifications do not influence the LLVM type, we just return a // pointer to the underlying interface type. We don't need to worry about // recursive conversion. llvm::Type *T = ConvertTypeForMem(cast(Ty)->getPointeeType()); ResultType = T->getPointerTo(); break; } case Type::Enum: { const EnumDecl *ED = cast(Ty)->getDecl(); if (ED->isCompleteDefinition() || ED->isFixed()) return ConvertType(ED->getIntegerType()); // Return a placeholder 'i32' type. This can be changed later when the // type is defined (see UpdateCompletedType), but is likely to be the // "right" answer. ResultType = llvm::Type::getInt32Ty(getLLVMContext()); break; } case Type::BlockPointer: { const QualType FTy = cast(Ty)->getPointeeType(); llvm::Type *PointeeType = ConvertTypeForMem(FTy); unsigned AS = Context.getTargetAddressSpace(FTy); ResultType = llvm::PointerType::get(PointeeType, AS); break; } case Type::MemberPointer: { ResultType = getCXXABI().ConvertMemberPointerType(cast(Ty)); break; } case Type::Atomic: { QualType valueType = cast(Ty)->getValueType(); ResultType = ConvertTypeForMem(valueType); // Pad out to the inflated size if necessary. uint64_t valueSize = Context.getTypeSize(valueType); uint64_t atomicSize = Context.getTypeSize(Ty); if (valueSize != atomicSize) { assert(valueSize < atomicSize); llvm::Type *elts[] = { ResultType, llvm::ArrayType::get(CGM.Int8Ty, (atomicSize - valueSize) / 8) }; ResultType = llvm::StructType::get(getLLVMContext(), llvm::makeArrayRef(elts)); } break; } } assert(ResultType && "Didn't convert a type?"); TypeCache[Ty] = ResultType; return ResultType; } bool CodeGenModule::isPaddedAtomicType(QualType type) { return isPaddedAtomicType(type->castAs()); } bool CodeGenModule::isPaddedAtomicType(const AtomicType *type) { return Context.getTypeSize(type) != Context.getTypeSize(type->getValueType()); } /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union. llvm::StructType *CodeGenTypes::ConvertRecordDeclType(const RecordDecl *RD) { // TagDecl's are not necessarily unique, instead use the (clang) // type connected to the decl. const Type *Key = Context.getTagDeclType(RD).getTypePtr(); llvm::StructType *&Entry = RecordDeclTypes[Key]; // If we don't have a StructType at all yet, create the forward declaration. if (Entry == 0) { Entry = llvm::StructType::create(getLLVMContext()); addRecordTypeName(RD, Entry, ""); } llvm::StructType *Ty = Entry; // If this is still a forward declaration, or the LLVM type is already // complete, there's nothing more to do. RD = RD->getDefinition(); if (RD == 0 || !RD->isCompleteDefinition() || !Ty->isOpaque()) return Ty; // If converting this type would cause us to infinitely loop, don't do it! if (!isSafeToConvert(RD, *this)) { DeferredRecords.push_back(RD); return Ty; } // Okay, this is a definition of a type. Compile the implementation now. bool InsertResult = RecordsBeingLaidOut.insert(Key); (void)InsertResult; assert(InsertResult && "Recursively compiling a struct?"); // Force conversion of non-virtual base classes recursively. if (const CXXRecordDecl *CRD = dyn_cast(RD)) { for (CXXRecordDecl::base_class_const_iterator i = CRD->bases_begin(), e = CRD->bases_end(); i != e; ++i) { if (i->isVirtual()) continue; ConvertRecordDeclType(i->getType()->getAs()->getDecl()); } } // Layout fields. CGRecordLayout *Layout = ComputeRecordLayout(RD, Ty); CGRecordLayouts[Key] = Layout; // We're done laying out this struct. bool EraseResult = RecordsBeingLaidOut.erase(Key); (void)EraseResult; assert(EraseResult && "struct not in RecordsBeingLaidOut set?"); // If this struct blocked a FunctionType conversion, then recompute whatever // was derived from that. // FIXME: This is hugely overconservative. if (SkippedLayout) TypeCache.clear(); // If we're done converting the outer-most record, then convert any deferred // structs as well. if (RecordsBeingLaidOut.empty()) while (!DeferredRecords.empty()) ConvertRecordDeclType(DeferredRecords.pop_back_val()); return Ty; } /// getCGRecordLayout - Return record layout info for the given record decl. const CGRecordLayout & CodeGenTypes::getCGRecordLayout(const RecordDecl *RD) { const Type *Key = Context.getTagDeclType(RD).getTypePtr(); const CGRecordLayout *Layout = CGRecordLayouts.lookup(Key); if (!Layout) { // Compute the type information. ConvertRecordDeclType(RD); // Now try again. Layout = CGRecordLayouts.lookup(Key); } assert(Layout && "Unable to find record layout information for type"); return *Layout; } bool CodeGenTypes::isZeroInitializable(QualType T) { // No need to check for member pointers when not compiling C++. if (!Context.getLangOpts().CPlusPlus) return true; T = Context.getBaseElementType(T); // Records are non-zero-initializable if they contain any // non-zero-initializable subobjects. if (const RecordType *RT = T->getAs()) { const CXXRecordDecl *RD = cast(RT->getDecl()); return isZeroInitializable(RD); } // We have to ask the ABI about member pointers. if (const MemberPointerType *MPT = T->getAs()) return getCXXABI().isZeroInitializable(MPT); // Everything else is okay. return true; } bool CodeGenTypes::isZeroInitializable(const CXXRecordDecl *RD) { return getCGRecordLayout(RD).isZeroInitializable(); }