| //===--- 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 "clang/Basic/TargetInfo.h" |
| #include "clang/AST/AST.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/Module.h" |
| #include "llvm/Target/TargetData.h" |
| |
| using namespace clang; |
| using namespace CodeGen; |
| |
| namespace { |
| /// RecordOrganizer - This helper class, used by CGRecordLayout, layouts |
| /// structs and unions. It manages transient information used during layout. |
| /// FIXME : Handle field aligments. Handle packed structs. |
| class RecordOrganizer { |
| public: |
| explicit RecordOrganizer(CodeGenTypes &Types) : |
| CGT(Types), STy(NULL), llvmFieldNo(0), Cursor(0), |
| llvmSize(0) {} |
| |
| /// addField - Add new field. |
| void addField(const FieldDecl *FD); |
| |
| /// addLLVMField - Add llvm struct field that corresponds to llvm type Ty. |
| /// Increment field count. |
| void addLLVMField(const llvm::Type *Ty, bool isPaddingField = false); |
| |
| /// addPaddingFields - Current cursor is not suitable place to add next |
| /// field. Add required padding fields. |
| void addPaddingFields(unsigned WaterMark); |
| |
| /// layoutStructFields - Do the actual work and lay out all fields. Create |
| /// corresponding llvm struct type. This should be invoked only after |
| /// all fields are added. |
| void layoutStructFields(const ASTRecordLayout &RL); |
| |
| /// layoutUnionFields - Do the actual work and lay out all fields. Create |
| /// corresponding llvm struct type. This should be invoked only after |
| /// all fields are added. |
| void layoutUnionFields(); |
| |
| /// getLLVMType - Return associated llvm struct type. This may be NULL |
| /// if fields are not laid out. |
| llvm::Type *getLLVMType() const { |
| return STy; |
| } |
| |
| /// placeBitField - Find a place for FD, which is a bit-field. |
| void placeBitField(const FieldDecl *FD); |
| |
| llvm::SmallSet<unsigned, 8> &getPaddingFields() { |
| return PaddingFields; |
| } |
| |
| private: |
| CodeGenTypes &CGT; |
| llvm::Type *STy; |
| unsigned llvmFieldNo; |
| uint64_t Cursor; |
| uint64_t llvmSize; |
| llvm::SmallVector<const FieldDecl *, 8> FieldDecls; |
| std::vector<const llvm::Type*> LLVMFields; |
| llvm::SmallSet<unsigned, 8> PaddingFields; |
| }; |
| } |
| |
| CodeGenTypes::CodeGenTypes(ASTContext &Ctx, llvm::Module& M, |
| const llvm::TargetData &TD) |
| : Context(Ctx), Target(Ctx.Target), TheModule(M), TheTargetData(TD) { |
| } |
| |
| CodeGenTypes::~CodeGenTypes() { |
| for(llvm::DenseMap<const TagDecl *, CGRecordLayout *>::iterator |
| I = CGRecordLayouts.begin(), E = CGRecordLayouts.end(); |
| I != E; ++I) |
| delete I->second; |
| CGRecordLayouts.clear(); |
| } |
| |
| /// ConvertType - Convert the specified type to its LLVM form. |
| const llvm::Type *CodeGenTypes::ConvertType(QualType T) { |
| llvm::PATypeHolder Result = ConvertTypeRecursive(T); |
| |
| // Any pointers that were converted defered evaluation of their pointee type, |
| // creating an opaque type instead. This is in order to avoid problems with |
| // circular types. Loop through all these defered pointees, if any, and |
| // resolve them now. |
| while (!PointersToResolve.empty()) { |
| std::pair<const PointerLikeType *, llvm::OpaqueType*> P = |
| PointersToResolve.back(); |
| PointersToResolve.pop_back(); |
| // We can handle bare pointers here because we know that the only pointers |
| // to the Opaque type are P.second and from other types. Refining the |
| // opqaue type away will invalidate P.second, but we don't mind :). |
| const llvm::Type *NT = ConvertTypeRecursive(P.first->getPointeeType()); |
| P.second->refineAbstractTypeTo(NT); |
| } |
| |
| return Result; |
| } |
| |
| const llvm::Type *CodeGenTypes::ConvertTypeRecursive(QualType T) { |
| // See if type is already cached. |
| llvm::DenseMap<Type *, llvm::PATypeHolder>::iterator |
| I = TypeCache.find(T.getCanonicalType().getTypePtr()); |
| // If type is found in map and this is not a definition for a opaque |
| // place holder type then use it. Otherwise, convert type T. |
| if (I != TypeCache.end()) |
| return I->second.get(); |
| |
| const llvm::Type *ResultType = ConvertNewType(T); |
| TypeCache.insert(std::make_pair(T.getCanonicalType().getTypePtr(), |
| llvm::PATypeHolder(ResultType))); |
| return ResultType; |
| } |
| |
| /// 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. |
| const llvm::Type *CodeGenTypes::ConvertTypeForMem(QualType T) { |
| const llvm::Type *R = ConvertType(T); |
| |
| // If this is a non-bool type, don't map it. |
| if (R != llvm::Type::Int1Ty) |
| return R; |
| |
| // Otherwise, return an integer of the target-specified size. |
| return llvm::IntegerType::get((unsigned)Context.getTypeSize(T)); |
| |
| } |
| |
| /// 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) { |
| llvm::DenseMap<const TagDecl*, llvm::PATypeHolder>::iterator TDTI = |
| TagDeclTypes.find(TD); |
| if (TDTI == TagDeclTypes.end()) return; |
| |
| // Remember the opaque LLVM type for this tagdecl. |
| llvm::PATypeHolder OpaqueHolder = TDTI->second; |
| assert(isa<llvm::OpaqueType>(OpaqueHolder.get()) && |
| "Updating compilation of an already non-opaque type?"); |
| |
| // Remove it from TagDeclTypes so that it will be regenerated. |
| TagDeclTypes.erase(TDTI); |
| |
| // Generate the new type. |
| const llvm::Type *NT = ConvertTagDeclType(TD); |
| |
| // Refine the old opaque type to its new definition. |
| cast<llvm::OpaqueType>(OpaqueHolder.get())->refineAbstractTypeTo(NT); |
| } |
| |
| /// Produces a vector containing the all of the instance variables in an |
| /// Objective-C object, in the order that they appear. Used to create LLVM |
| /// structures corresponding to Objective-C objects. |
| void CodeGenTypes::CollectObjCIvarTypes(ObjCInterfaceDecl *ObjCClass, |
| std::vector<const llvm::Type*> &IvarTypes) { |
| ObjCInterfaceDecl *SuperClass = ObjCClass->getSuperClass(); |
| if (SuperClass) |
| CollectObjCIvarTypes(SuperClass, IvarTypes); |
| for (ObjCInterfaceDecl::ivar_iterator I = ObjCClass->ivar_begin(), |
| E = ObjCClass->ivar_end(); I != E; ++I) { |
| IvarTypes.push_back(ConvertType((*I)->getType())); |
| ObjCIvarInfo[*I] = IvarTypes.size() - 1; |
| } |
| } |
| |
| const llvm::Type *CodeGenTypes::ConvertNewType(QualType T) { |
| const clang::Type &Ty = *T.getCanonicalType(); |
| |
| switch (Ty.getTypeClass()) { |
| case Type::TypeName: // typedef isn't canonical. |
| case Type::TypeOfExp: // typeof isn't canonical. |
| case Type::TypeOfTyp: // typeof isn't canonical. |
| assert(0 && "Non-canonical type, shouldn't happen"); |
| case Type::Builtin: { |
| switch (cast<BuiltinType>(Ty).getKind()) { |
| case BuiltinType::Void: |
| // LLVM void type can only be used as the result of a function call. Just |
| // map to the same as char. |
| return llvm::IntegerType::get(8); |
| |
| case BuiltinType::Bool: |
| // Note that we always return bool as i1 for use as a scalar type. |
| return llvm::Type::Int1Ty; |
| |
| 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: |
| return llvm::IntegerType::get( |
| static_cast<unsigned>(Context.getTypeSize(T))); |
| |
| case BuiltinType::Float: return llvm::Type::FloatTy; |
| case BuiltinType::Double: |
| return (Context.Target.getDoubleFormat() == &llvm::APFloat::IEEEdouble) ? |
| llvm::Type::DoubleTy : llvm::Type::FloatTy; |
| case BuiltinType::LongDouble: |
| // FIXME: mapping long double onto double. |
| return llvm::Type::DoubleTy; |
| } |
| break; |
| } |
| case Type::Complex: { |
| const llvm::Type *EltTy = |
| ConvertTypeRecursive(cast<ComplexType>(Ty).getElementType()); |
| return llvm::StructType::get(EltTy, EltTy, NULL); |
| } |
| case Type::Reference: |
| case Type::Pointer: { |
| const PointerLikeType &PTy = cast<PointerLikeType>(Ty); |
| QualType ETy = PTy.getPointeeType(); |
| llvm::OpaqueType *PointeeType = llvm::OpaqueType::get(); |
| PointersToResolve.push_back(std::make_pair(&PTy, PointeeType)); |
| return llvm::PointerType::get(PointeeType, ETy.getAddressSpace()); |
| } |
| |
| case Type::VariableArray: { |
| const VariableArrayType &A = cast<VariableArrayType>(Ty); |
| assert(A.getIndexTypeQualifier() == 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. |
| return ConvertTypeRecursive(A.getElementType()); |
| } |
| case Type::IncompleteArray: { |
| const IncompleteArrayType &A = cast<IncompleteArrayType>(Ty); |
| assert(A.getIndexTypeQualifier() == 0 && |
| "FIXME: We only handle trivial array types so far!"); |
| // int X[] -> [0 x int] |
| return llvm::ArrayType::get(ConvertTypeRecursive(A.getElementType()), 0); |
| } |
| case Type::ConstantArray: { |
| const ConstantArrayType &A = cast<ConstantArrayType>(Ty); |
| const llvm::Type *EltTy = ConvertTypeRecursive(A.getElementType()); |
| return llvm::ArrayType::get(EltTy, A.getSize().getZExtValue()); |
| } |
| case Type::ExtVector: |
| case Type::Vector: { |
| const VectorType &VT = cast<VectorType>(Ty); |
| return llvm::VectorType::get(ConvertTypeRecursive(VT.getElementType()), |
| VT.getNumElements()); |
| } |
| case Type::FunctionNoProto: |
| case Type::FunctionProto: { |
| const FunctionType &FP = cast<FunctionType>(Ty); |
| const llvm::Type *ResultType; |
| |
| if (FP.getResultType()->isVoidType()) |
| ResultType = llvm::Type::VoidTy; // Result of function uses llvm void. |
| else |
| ResultType = ConvertTypeRecursive(FP.getResultType()); |
| |
| // FIXME: Convert argument types. |
| bool isVarArg; |
| std::vector<const llvm::Type*> ArgTys; |
| |
| // Struct return passes the struct byref. |
| if (!ResultType->isFirstClassType() && ResultType != llvm::Type::VoidTy) { |
| ArgTys.push_back(llvm::PointerType::get(ResultType, |
| FP.getResultType().getAddressSpace())); |
| ResultType = llvm::Type::VoidTy; |
| } |
| |
| if (const FunctionTypeProto *FTP = dyn_cast<FunctionTypeProto>(&FP)) { |
| DecodeArgumentTypes(*FTP, ArgTys); |
| isVarArg = FTP->isVariadic(); |
| } else { |
| isVarArg = true; |
| } |
| |
| return llvm::FunctionType::get(ResultType, ArgTys, isVarArg); |
| } |
| |
| case Type::ASQual: |
| return |
| ConvertTypeRecursive(QualType(cast<ASQualType>(Ty).getBaseType(), 0)); |
| |
| case Type::ObjCInterface: { |
| // Warning: Use of this is strongly discouraged. Late binding of instance |
| // variables is supported on some runtimes and so using static binding can |
| // break code when libraries are updated. Only use this if you have |
| // previously checked that the ObjCRuntime subclass in use does not support |
| // late-bound ivars. |
| ObjCInterfaceType OIT = cast<ObjCInterfaceType>(Ty); |
| std::vector<const llvm::Type*> IvarTypes; |
| // Pointer to the class. This is just a placeholder. Operations that |
| // actually use the isa pointer should cast it to the Class type provided |
| // by the runtime. |
| IvarTypes.push_back(llvm::PointerType::getUnqual(llvm::Type::Int8Ty)); |
| CollectObjCIvarTypes(OIT.getDecl(), IvarTypes); |
| return llvm::StructType::get(IvarTypes); |
| } |
| |
| case Type::ObjCQualifiedInterface: |
| assert(0 && "FIXME: add missing functionality here"); |
| break; |
| |
| case Type::ObjCQualifiedId: |
| assert(0 && "FIXME: add missing functionality here"); |
| break; |
| |
| case Type::Tagged: { |
| const TagDecl *TD = cast<TagType>(Ty).getDecl(); |
| const llvm::Type *Res = ConvertTagDeclType(TD); |
| |
| std::string TypeName(TD->getKindName()); |
| TypeName += '.'; |
| |
| // Name the codegen type after the typedef name |
| // if there is no tag type name available |
| if (TD->getIdentifier()) |
| TypeName += TD->getName(); |
| else if (const TypedefType *TdT = dyn_cast<TypedefType>(T)) |
| TypeName += TdT->getDecl()->getName(); |
| else |
| TypeName += "anon"; |
| |
| TheModule.addTypeName(TypeName, Res); |
| return Res; |
| } |
| } |
| |
| // FIXME: implement. |
| return llvm::OpaqueType::get(); |
| } |
| |
| void CodeGenTypes::DecodeArgumentTypes(const FunctionTypeProto &FTP, |
| std::vector<const llvm::Type*> &ArgTys) { |
| for (unsigned i = 0, e = FTP.getNumArgs(); i != e; ++i) { |
| const llvm::Type *Ty = ConvertTypeRecursive(FTP.getArgType(i)); |
| if (Ty->isFirstClassType()) |
| ArgTys.push_back(Ty); |
| else |
| // byval arguments are always on the stack, which is addr space #0. |
| ArgTys.push_back(llvm::PointerType::getUnqual(Ty)); |
| } |
| } |
| |
| /// ConvertTagDeclType - Lay out a tagged decl type like struct or union or |
| /// enum. |
| const llvm::Type *CodeGenTypes::ConvertTagDeclType(const TagDecl *TD) { |
| llvm::DenseMap<const TagDecl*, llvm::PATypeHolder>::iterator TDTI = |
| TagDeclTypes.find(TD); |
| |
| // If we've already compiled this tag type, use the previous definition. |
| if (TDTI != TagDeclTypes.end()) |
| return TDTI->second; |
| |
| // If this is still a forward definition, just define an opaque type to use |
| // for this tagged decl. |
| if (!TD->isDefinition()) { |
| llvm::Type *ResultType = llvm::OpaqueType::get(); |
| TagDeclTypes.insert(std::make_pair(TD, ResultType)); |
| return ResultType; |
| } |
| |
| // Okay, this is a definition of a type. Compile the implementation now. |
| |
| if (TD->getKind() == Decl::Enum) { |
| // Don't bother storing enums in TagDeclTypes. |
| return ConvertTypeRecursive(cast<EnumDecl>(TD)->getIntegerType()); |
| } |
| |
| // This decl could well be recursive. In this case, insert an opaque |
| // definition of this type, which the recursive uses will get. We will then |
| // refine this opaque version later. |
| |
| // Create new OpaqueType now for later use in case this is a recursive |
| // type. This will later be refined to the actual type. |
| llvm::PATypeHolder ResultHolder = llvm::OpaqueType::get(); |
| TagDeclTypes.insert(std::make_pair(TD, ResultHolder)); |
| |
| const llvm::Type *ResultType; |
| const RecordDecl *RD = cast<const RecordDecl>(TD); |
| if (TD->getKind() == Decl::Struct || TD->getKind() == Decl::Class) { |
| // Layout fields. |
| RecordOrganizer RO(*this); |
| for (unsigned i = 0, e = RD->getNumMembers(); i != e; ++i) |
| RO.addField(RD->getMember(i)); |
| |
| RO.layoutStructFields(Context.getASTRecordLayout(RD)); |
| |
| // Get llvm::StructType. |
| CGRecordLayouts[TD] = new CGRecordLayout(RO.getLLVMType(), |
| RO.getPaddingFields()); |
| ResultType = RO.getLLVMType(); |
| |
| } else if (TD->getKind() == Decl::Union) { |
| // Just use the largest element of the union, breaking ties with the |
| // highest aligned member. |
| if (RD->getNumMembers() != 0) { |
| RecordOrganizer RO(*this); |
| for (unsigned i = 0, e = RD->getNumMembers(); i != e; ++i) |
| RO.addField(RD->getMember(i)); |
| |
| RO.layoutUnionFields(); |
| |
| // Get llvm::StructType. |
| CGRecordLayouts[TD] = new CGRecordLayout(RO.getLLVMType(), |
| RO.getPaddingFields()); |
| ResultType = RO.getLLVMType(); |
| } else { |
| ResultType = llvm::StructType::get(std::vector<const llvm::Type*>()); |
| } |
| } else { |
| assert(0 && "FIXME: Unknown tag decl kind!"); |
| } |
| |
| // Refine our Opaque type to ResultType. This can invalidate ResultType, so |
| // make sure to read the result out of the holder. |
| cast<llvm::OpaqueType>(ResultHolder.get()) |
| ->refineAbstractTypeTo(ResultType); |
| |
| return ResultHolder.get(); |
| } |
| |
| /// getLLVMFieldNo - Return llvm::StructType element number |
| /// that corresponds to the field FD. |
| unsigned CodeGenTypes::getLLVMFieldNo(const FieldDecl *FD) { |
| llvm::DenseMap<const FieldDecl*, unsigned>::iterator I = FieldInfo.find(FD); |
| assert (I != FieldInfo.end() && "Unable to find field info"); |
| return I->second; |
| } |
| |
| unsigned CodeGenTypes::getLLVMFieldNo(const ObjCIvarDecl *OID) { |
| llvm::DenseMap<const ObjCIvarDecl*, unsigned>::iterator |
| I = ObjCIvarInfo.find(OID); |
| assert(I != ObjCIvarInfo.end() && "Unable to find field info"); |
| return I->second; |
| } |
| |
| /// addFieldInfo - Assign field number to field FD. |
| void CodeGenTypes::addFieldInfo(const FieldDecl *FD, unsigned No) { |
| FieldInfo[FD] = No; |
| } |
| |
| /// getBitFieldInfo - Return the BitFieldInfo that corresponds to the field FD. |
| CodeGenTypes::BitFieldInfo CodeGenTypes::getBitFieldInfo(const FieldDecl *FD) { |
| llvm::DenseMap<const FieldDecl *, BitFieldInfo>::iterator |
| I = BitFields.find(FD); |
| assert (I != BitFields.end() && "Unable to find bitfield info"); |
| return I->second; |
| } |
| |
| /// addBitFieldInfo - Assign a start bit and a size to field FD. |
| void CodeGenTypes::addBitFieldInfo(const FieldDecl *FD, unsigned Begin, |
| unsigned Size) { |
| BitFields.insert(std::make_pair(FD, BitFieldInfo(Begin, Size))); |
| } |
| |
| /// getCGRecordLayout - Return record layout info for the given llvm::Type. |
| const CGRecordLayout * |
| CodeGenTypes::getCGRecordLayout(const TagDecl *TD) const { |
| llvm::DenseMap<const TagDecl*, CGRecordLayout *>::iterator I |
| = CGRecordLayouts.find(TD); |
| assert (I != CGRecordLayouts.end() |
| && "Unable to find record layout information for type"); |
| return I->second; |
| } |
| |
| /// addField - Add new field. |
| void RecordOrganizer::addField(const FieldDecl *FD) { |
| assert (!STy && "Record fields are already laid out"); |
| FieldDecls.push_back(FD); |
| } |
| |
| /// layoutStructFields - Do the actual work and lay out all fields. Create |
| /// corresponding llvm struct type. This should be invoked only after |
| /// all fields are added. |
| /// FIXME : At the moment assume |
| /// - one to one mapping between AST FieldDecls and |
| /// llvm::StructType elements. |
| /// - Ignore bit fields |
| /// - Ignore field aligments |
| /// - Ignore packed structs |
| void RecordOrganizer::layoutStructFields(const ASTRecordLayout &RL) { |
| // FIXME : Use SmallVector |
| llvmSize = 0; |
| llvmFieldNo = 0; |
| Cursor = 0; |
| LLVMFields.clear(); |
| |
| for (llvm::SmallVector<const FieldDecl *, 8>::iterator I = FieldDecls.begin(), |
| E = FieldDecls.end(); I != E; ++I) { |
| const FieldDecl *FD = *I; |
| |
| if (FD->isBitField()) |
| placeBitField(FD); |
| else { |
| const llvm::Type *Ty = CGT.ConvertTypeRecursive(FD->getType()); |
| addLLVMField(Ty); |
| CGT.addFieldInfo(FD, llvmFieldNo - 1); |
| Cursor = llvmSize; |
| } |
| } |
| |
| unsigned StructAlign = RL.getAlignment(); |
| if (llvmSize % StructAlign) { |
| unsigned StructPadding = StructAlign - (llvmSize % StructAlign); |
| bool needStructPadding = true; |
| if (!LLVMFields.empty()) { |
| const llvm::Type *LastFieldType = LLVMFields.back(); |
| const llvm::Type *LastFieldDeclType = |
| CGT.ConvertTypeRecursive(FieldDecls.back()->getType()); |
| if (LastFieldType != LastFieldDeclType) { |
| unsigned LastFieldTypeSize = |
| CGT.getTargetData().getABITypeSizeInBits(LastFieldType); |
| unsigned LastFieldDeclTypeSize = |
| CGT.getTargetData().getABITypeSizeInBits(LastFieldDeclType); |
| if (LastFieldDeclTypeSize > LastFieldTypeSize |
| && StructPadding == (LastFieldDeclTypeSize - LastFieldTypeSize)) { |
| // Replace last LLVMField with a LastFieldDeclType field will |
| // to avoid extra padding fields. |
| LLVMFields.pop_back(); |
| LLVMFields.push_back(LastFieldDeclType); |
| needStructPadding = false; |
| } |
| } |
| } |
| if (needStructPadding) |
| addPaddingFields(llvmSize + StructPadding); |
| } |
| |
| STy = llvm::StructType::get(LLVMFields); |
| } |
| |
| /// addPaddingFields - Current cursor is not suitable place to add next field. |
| /// Add required padding fields. |
| void RecordOrganizer::addPaddingFields(unsigned WaterMark) { |
| assert(WaterMark >= llvmSize && "Invalid padding Field"); |
| unsigned RequiredBits = WaterMark - llvmSize; |
| unsigned RequiredBytes = (RequiredBits + 7) / 8; |
| if (RequiredBytes == 1) |
| // This is a bitfield that is using few bits from this byte. |
| // It is not a padding field. |
| addLLVMField(llvm::Type::Int8Ty, false); |
| else |
| for (unsigned i = 0; i != RequiredBytes; ++i) |
| addLLVMField(llvm::Type::Int8Ty, true); |
| } |
| |
| /// addLLVMField - Add llvm struct field that corresponds to llvm type Ty. |
| /// Increment field count. |
| void RecordOrganizer::addLLVMField(const llvm::Type *Ty, bool isPaddingField) { |
| |
| unsigned AlignmentInBits = CGT.getTargetData().getABITypeAlignment(Ty) * 8; |
| if (llvmSize % AlignmentInBits) { |
| // At the moment, insert padding fields even if target specific llvm |
| // type alignment enforces implict padding fields for FD. Later on, |
| // optimize llvm fields by removing implicit padding fields and |
| // combining consequetive padding fields. |
| unsigned Padding = AlignmentInBits - (llvmSize % AlignmentInBits); |
| addPaddingFields(llvmSize + Padding); |
| } |
| |
| unsigned TySize = CGT.getTargetData().getABITypeSizeInBits(Ty); |
| llvmSize += TySize; |
| if (isPaddingField) |
| PaddingFields.insert(llvmFieldNo); |
| LLVMFields.push_back(Ty); |
| ++llvmFieldNo; |
| } |
| |
| /// layoutUnionFields - Do the actual work and lay out all fields. Create |
| /// corresponding llvm struct type. This should be invoked only after |
| /// all fields are added. |
| void RecordOrganizer::layoutUnionFields() { |
| |
| unsigned PrimaryEltNo = 0; |
| std::pair<uint64_t, unsigned> PrimaryElt = |
| CGT.getContext().getTypeInfo(FieldDecls[0]->getType()); |
| if (FieldDecls[0]->isBitField()) |
| placeBitField(FieldDecls[0]); |
| else |
| CGT.addFieldInfo(FieldDecls[0], 0); |
| |
| unsigned Size = FieldDecls.size(); |
| for(unsigned i = 1; i != Size; ++i) { |
| const FieldDecl *FD = FieldDecls[i]; |
| std::pair<uint64_t, unsigned> EltInfo = |
| CGT.getContext().getTypeInfo(FD->getType()); |
| |
| // Use largest element, breaking ties with the hightest aligned member. |
| if (EltInfo.first > PrimaryElt.first || |
| (EltInfo.first == PrimaryElt.first && |
| EltInfo.second > PrimaryElt.second)) { |
| PrimaryElt = EltInfo; |
| PrimaryEltNo = i; |
| } |
| |
| // In union, each field gets first slot. |
| if (FD->isBitField()) |
| placeBitField(FD); |
| else |
| CGT.addFieldInfo(FD, 0); |
| } |
| |
| std::vector<const llvm::Type*> Fields; |
| const llvm::Type *Ty = |
| CGT.ConvertTypeRecursive(FieldDecls[PrimaryEltNo]->getType()); |
| Fields.push_back(Ty); |
| STy = llvm::StructType::get(Fields); |
| } |
| |
| /// placeBitField - Find a place for FD, which is a bit-field. |
| /// This function searches for the last aligned field. If the bit-field fits in |
| /// it, it is reused. Otherwise, the bit-field is placed in a new field. |
| void RecordOrganizer::placeBitField(const FieldDecl *FD) { |
| |
| assert (FD->isBitField() && "FD is not a bit-field"); |
| Expr *BitWidth = FD->getBitWidth(); |
| llvm::APSInt FieldSize(32); |
| bool isBitField = |
| BitWidth->isIntegerConstantExpr(FieldSize, CGT.getContext()); |
| assert (isBitField && "Invalid BitField size expression"); |
| uint64_t BitFieldSize = FieldSize.getZExtValue(); |
| |
| const llvm::Type *Ty = CGT.ConvertTypeRecursive(FD->getType()); |
| uint64_t TySize = CGT.getTargetData().getABITypeSizeInBits(Ty); |
| |
| unsigned Idx = Cursor / TySize; |
| unsigned BitsLeft = TySize - (Cursor % TySize); |
| |
| if (BitsLeft >= BitFieldSize) { |
| // The bitfield fits in the last aligned field. |
| // This is : struct { char a; int CurrentField:10;}; |
| // where 'CurrentField' shares first field with 'a'. |
| CGT.addFieldInfo(FD, Idx); |
| CGT.addBitFieldInfo(FD, TySize - BitsLeft, BitFieldSize); |
| Cursor += BitFieldSize; |
| } else { |
| // Place the bitfield in a new LLVM field. |
| // This is : struct { char a; short CurrentField:10;}; |
| // where 'CurrentField' needs a new llvm field. |
| CGT.addFieldInfo(FD, Idx + 1); |
| CGT.addBitFieldInfo(FD, 0, BitFieldSize); |
| Cursor = (Idx + 1) * TySize + BitFieldSize; |
| } |
| if (Cursor > llvmSize) |
| addPaddingFields(Cursor); |
| } |