//===--- 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 &getPaddingFields() { return PaddingFields; } private: CodeGenTypes &CGT; llvm::Type *STy; unsigned llvmFieldNo; uint64_t Cursor; uint64_t llvmSize; llvm::SmallVector FieldDecls; std::vector LLVMFields; llvm::SmallSet 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::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) { // See if type is already cached. llvm::DenseMap::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::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(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(OpaqueHolder.get())->refineAbstractTypeTo(NT); } 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(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(Context.getTypeSize(T))); case BuiltinType::Float: return llvm::Type::FloatTy; case BuiltinType::Double: return llvm::Type::DoubleTy; case BuiltinType::LongDouble: // FIXME: mapping long double onto double. return llvm::Type::DoubleTy; } break; } case Type::Complex: { const llvm::Type *EltTy = ConvertType(cast(Ty).getElementType()); return llvm::StructType::get(EltTy, EltTy, NULL); } case Type::Pointer: { const PointerType &P = cast(Ty); QualType ETy = P.getPointeeType(); return llvm::PointerType::get(ConvertType(ETy), ETy.getAddressSpace()); } case Type::Reference: { const ReferenceType &R = cast(Ty); return llvm::PointerType::getUnqual(ConvertType(R.getReferenceeType())); } case Type::VariableArray: { const VariableArrayType &A = cast(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 ConvertType(A.getElementType()); } case Type::IncompleteArray: { const IncompleteArrayType &A = cast(Ty); assert(A.getIndexTypeQualifier() == 0 && "FIXME: We only handle trivial array types so far!"); // int X[] -> [0 x int] return llvm::ArrayType::get(ConvertType(A.getElementType()), 0); } case Type::ConstantArray: { const ConstantArrayType &A = cast(Ty); const llvm::Type *EltTy = ConvertType(A.getElementType()); return llvm::ArrayType::get(EltTy, A.getSize().getZExtValue()); } case Type::OCUVector: case Type::Vector: { const VectorType &VT = cast(Ty); return llvm::VectorType::get(ConvertType(VT.getElementType()), VT.getNumElements()); } case Type::FunctionNoProto: case Type::FunctionProto: { const FunctionType &FP = cast(Ty); const llvm::Type *ResultType; if (FP.getResultType()->isVoidType()) ResultType = llvm::Type::VoidTy; // Result of function uses llvm void. else ResultType = ConvertType(FP.getResultType()); // FIXME: Convert argument types. bool isVarArg; std::vector 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(&FP)) { DecodeArgumentTypes(*FTP, ArgTys); isVarArg = FTP->isVariadic(); } else { isVarArg = true; } return llvm::FunctionType::get(ResultType, ArgTys, isVarArg); } case Type::ASQual: return ConvertType(QualType(cast(Ty).getBaseType(), 0)); case Type::ObjCInterface: assert(0 && "FIXME: add missing functionality here"); break; 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(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(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 &ArgTys) { for (unsigned i = 0, e = FTP.getNumArgs(); i != e; ++i) { const llvm::Type *Ty = ConvertType(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::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 ConvertType(cast(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(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()); } } 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(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::iterator I = FieldInfo.find(FD); assert (I != FieldInfo.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::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::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::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.ConvertType(FD->getType()); addLLVMField(Ty); CGT.addFieldInfo(FD, llvmFieldNo - 1); Cursor = llvmSize; } } unsigned StructAlign = RL.getAlignment(); if (llvmSize % StructAlign) { unsigned StructPadding = StructAlign - (llvmSize % StructAlign); 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; 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 PrimaryElt = CGT.getContext().getTypeInfo(FieldDecls[0]->getType()); CGT.addFieldInfo(FieldDecls[0], 0); unsigned Size = FieldDecls.size(); for(unsigned i = 1; i != Size; ++i) { const FieldDecl *FD = FieldDecls[i]; assert (!FD->isBitField() && "Bit fields are not yet supported"); std::pair 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. CGT.addFieldInfo(FD, 0); } std::vector Fields; const llvm::Type *Ty = CGT.ConvertType(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.ConvertType(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); }