| //===--- CGRecordLayoutBuilder.cpp - CGRecordLayout builder ----*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Builder implementation for CGRecordLayout objects. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CGRecordLayout.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/Attr.h" |
| #include "clang/AST/DeclCXX.h" |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/RecordLayout.h" |
| #include "CodeGenTypes.h" |
| #include "CGCXXABI.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/Type.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetData.h" |
| using namespace clang; |
| using namespace CodeGen; |
| |
| namespace clang { |
| namespace CodeGen { |
| |
| class CGRecordLayoutBuilder { |
| public: |
| /// FieldTypes - Holds the LLVM types that the struct is created from. |
| std::vector<const llvm::Type *> FieldTypes; |
| |
| /// NonVirtualBaseFieldTypes - Holds the LLVM types for the non-virtual part |
| /// of the struct. For example, consider: |
| /// |
| /// struct A { int i; }; |
| /// struct B { void *v; }; |
| /// struct C : virtual A, B { }; |
| /// |
| /// The LLVM type of C will be |
| /// %struct.C = type { i32 (...)**, %struct.A, i32, %struct.B } |
| /// |
| /// And the LLVM type of the non-virtual base struct will be |
| /// %struct.C.base = type { i32 (...)**, %struct.A, i32 } |
| std::vector<const llvm::Type *> NonVirtualBaseFieldTypes; |
| |
| /// NonVirtualBaseTypeIsSameAsCompleteType - Whether the non-virtual part of |
| /// the struct is equivalent to the complete struct. |
| bool NonVirtualBaseTypeIsSameAsCompleteType; |
| |
| /// LLVMFieldInfo - Holds a field and its corresponding LLVM field number. |
| typedef std::pair<const FieldDecl *, unsigned> LLVMFieldInfo; |
| llvm::SmallVector<LLVMFieldInfo, 16> LLVMFields; |
| |
| /// LLVMBitFieldInfo - Holds location and size information about a bit field. |
| typedef std::pair<const FieldDecl *, CGBitFieldInfo> LLVMBitFieldInfo; |
| llvm::SmallVector<LLVMBitFieldInfo, 16> LLVMBitFields; |
| |
| typedef std::pair<const CXXRecordDecl *, unsigned> LLVMBaseInfo; |
| llvm::SmallVector<LLVMBaseInfo, 16> LLVMNonVirtualBases; |
| |
| /// IsZeroInitializable - Whether this struct can be C++ |
| /// zero-initialized with an LLVM zeroinitializer. |
| bool IsZeroInitializable; |
| |
| /// Packed - Whether the resulting LLVM struct will be packed or not. |
| bool Packed; |
| |
| private: |
| CodeGenTypes &Types; |
| |
| /// Alignment - Contains the alignment of the RecordDecl. |
| // |
| // FIXME: This is not needed and should be removed. |
| unsigned Alignment; |
| |
| /// AlignmentAsLLVMStruct - Will contain the maximum alignment of all the |
| /// LLVM types. |
| unsigned AlignmentAsLLVMStruct; |
| |
| /// BitsAvailableInLastField - If a bit field spans only part of a LLVM field, |
| /// this will have the number of bits still available in the field. |
| char BitsAvailableInLastField; |
| |
| /// NextFieldOffsetInBytes - Holds the next field offset in bytes. |
| uint64_t NextFieldOffsetInBytes; |
| |
| /// LayoutUnionField - Will layout a field in an union and return the type |
| /// that the field will have. |
| const llvm::Type *LayoutUnionField(const FieldDecl *Field, |
| const ASTRecordLayout &Layout); |
| |
| /// LayoutUnion - Will layout a union RecordDecl. |
| void LayoutUnion(const RecordDecl *D); |
| |
| /// LayoutField - try to layout all fields in the record decl. |
| /// Returns false if the operation failed because the struct is not packed. |
| bool LayoutFields(const RecordDecl *D); |
| |
| /// LayoutNonVirtualBase - layout a single non-virtual base. |
| void LayoutNonVirtualBase(const CXXRecordDecl *BaseDecl, |
| uint64_t BaseOffset); |
| |
| /// LayoutNonVirtualBases - layout the non-virtual bases of a record decl. |
| void LayoutNonVirtualBases(const CXXRecordDecl *RD, |
| const ASTRecordLayout &Layout); |
| |
| /// ComputeNonVirtualBaseType - Compute the non-virtual base field types. |
| void ComputeNonVirtualBaseType(const CXXRecordDecl *RD); |
| |
| /// LayoutField - layout a single field. Returns false if the operation failed |
| /// because the current struct is not packed. |
| bool LayoutField(const FieldDecl *D, uint64_t FieldOffset); |
| |
| /// LayoutBitField - layout a single bit field. |
| void LayoutBitField(const FieldDecl *D, uint64_t FieldOffset); |
| |
| /// AppendField - Appends a field with the given offset and type. |
| void AppendField(uint64_t FieldOffsetInBytes, const llvm::Type *FieldTy); |
| |
| /// AppendPadding - Appends enough padding bytes so that the total |
| /// struct size is a multiple of the field alignment. |
| void AppendPadding(uint64_t FieldOffsetInBytes, unsigned FieldAlignment); |
| |
| /// getByteArrayType - Returns a byte array type with the given number of |
| /// elements. |
| const llvm::Type *getByteArrayType(uint64_t NumBytes); |
| |
| /// AppendBytes - Append a given number of bytes to the record. |
| void AppendBytes(uint64_t NumBytes); |
| |
| /// AppendTailPadding - Append enough tail padding so that the type will have |
| /// the passed size. |
| void AppendTailPadding(uint64_t RecordSize); |
| |
| unsigned getTypeAlignment(const llvm::Type *Ty) const; |
| |
| /// getCGRecordLayout - Return the CGRecordLayout for the given record. |
| const CGRecordLayout &getCGRecordLayout(const CXXRecordDecl *RD); |
| |
| /// CheckZeroInitializable - Check if the given type contains a pointer |
| /// to data member. |
| void CheckZeroInitializable(QualType T); |
| void CheckZeroInitializable(const CXXRecordDecl *RD); |
| |
| public: |
| CGRecordLayoutBuilder(CodeGenTypes &Types) |
| : NonVirtualBaseTypeIsSameAsCompleteType(false), IsZeroInitializable(true), |
| Packed(false), Types(Types), Alignment(0), AlignmentAsLLVMStruct(1), |
| BitsAvailableInLastField(0), NextFieldOffsetInBytes(0) { } |
| |
| /// Layout - Will layout a RecordDecl. |
| void Layout(const RecordDecl *D); |
| }; |
| |
| } |
| } |
| |
| void CGRecordLayoutBuilder::Layout(const RecordDecl *D) { |
| Alignment = Types.getContext().getASTRecordLayout(D).getAlignment() / 8; |
| Packed = D->hasAttr<PackedAttr>(); |
| |
| if (D->isUnion()) { |
| LayoutUnion(D); |
| return; |
| } |
| |
| if (LayoutFields(D)) |
| return; |
| |
| // We weren't able to layout the struct. Try again with a packed struct |
| Packed = true; |
| AlignmentAsLLVMStruct = 1; |
| NextFieldOffsetInBytes = 0; |
| FieldTypes.clear(); |
| LLVMFields.clear(); |
| LLVMBitFields.clear(); |
| LLVMNonVirtualBases.clear(); |
| |
| LayoutFields(D); |
| } |
| |
| CGBitFieldInfo CGBitFieldInfo::MakeInfo(CodeGenTypes &Types, |
| const FieldDecl *FD, |
| uint64_t FieldOffset, |
| uint64_t FieldSize, |
| uint64_t ContainingTypeSizeInBits, |
| unsigned ContainingTypeAlign) { |
| const llvm::Type *Ty = Types.ConvertTypeForMemRecursive(FD->getType()); |
| uint64_t TypeSizeInBytes = Types.getTargetData().getTypeAllocSize(Ty); |
| uint64_t TypeSizeInBits = TypeSizeInBytes * 8; |
| |
| bool IsSigned = FD->getType()->isSignedIntegerType(); |
| |
| if (FieldSize > TypeSizeInBits) { |
| // We have a wide bit-field. The extra bits are only used for padding, so |
| // if we have a bitfield of type T, with size N: |
| // |
| // T t : N; |
| // |
| // We can just assume that it's: |
| // |
| // T t : sizeof(T); |
| // |
| FieldSize = TypeSizeInBits; |
| } |
| |
| // Compute the access components. The policy we use is to start by attempting |
| // to access using the width of the bit-field type itself and to always access |
| // at aligned indices of that type. If such an access would fail because it |
| // extends past the bound of the type, then we reduce size to the next smaller |
| // power of two and retry. The current algorithm assumes pow2 sized types, |
| // although this is easy to fix. |
| // |
| // FIXME: This algorithm is wrong on big-endian systems, I think. |
| assert(llvm::isPowerOf2_32(TypeSizeInBits) && "Unexpected type size!"); |
| CGBitFieldInfo::AccessInfo Components[3]; |
| unsigned NumComponents = 0; |
| unsigned AccessedTargetBits = 0; // The tumber of target bits accessed. |
| unsigned AccessWidth = TypeSizeInBits; // The current access width to attempt. |
| |
| // Round down from the field offset to find the first access position that is |
| // at an aligned offset of the initial access type. |
| uint64_t AccessStart = FieldOffset - (FieldOffset % AccessWidth); |
| |
| // Adjust initial access size to fit within record. |
| while (AccessWidth > 8 && |
| AccessStart + AccessWidth > ContainingTypeSizeInBits) { |
| AccessWidth >>= 1; |
| AccessStart = FieldOffset - (FieldOffset % AccessWidth); |
| } |
| |
| while (AccessedTargetBits < FieldSize) { |
| // Check that we can access using a type of this size, without reading off |
| // the end of the structure. This can occur with packed structures and |
| // -fno-bitfield-type-align, for example. |
| if (AccessStart + AccessWidth > ContainingTypeSizeInBits) { |
| // If so, reduce access size to the next smaller power-of-two and retry. |
| AccessWidth >>= 1; |
| assert(AccessWidth >= 8 && "Cannot access under byte size!"); |
| continue; |
| } |
| |
| // Otherwise, add an access component. |
| |
| // First, compute the bits inside this access which are part of the |
| // target. We are reading bits [AccessStart, AccessStart + AccessWidth); the |
| // intersection with [FieldOffset, FieldOffset + FieldSize) gives the bits |
| // in the target that we are reading. |
| assert(FieldOffset < AccessStart + AccessWidth && "Invalid access start!"); |
| assert(AccessStart < FieldOffset + FieldSize && "Invalid access start!"); |
| uint64_t AccessBitsInFieldStart = std::max(AccessStart, FieldOffset); |
| uint64_t AccessBitsInFieldSize = |
| std::min(AccessWidth + AccessStart, |
| FieldOffset + FieldSize) - AccessBitsInFieldStart; |
| |
| assert(NumComponents < 3 && "Unexpected number of components!"); |
| CGBitFieldInfo::AccessInfo &AI = Components[NumComponents++]; |
| AI.FieldIndex = 0; |
| // FIXME: We still follow the old access pattern of only using the field |
| // byte offset. We should switch this once we fix the struct layout to be |
| // pretty. |
| AI.FieldByteOffset = AccessStart / 8; |
| AI.FieldBitStart = AccessBitsInFieldStart - AccessStart; |
| AI.AccessWidth = AccessWidth; |
| AI.AccessAlignment = llvm::MinAlign(ContainingTypeAlign, AccessStart) / 8; |
| AI.TargetBitOffset = AccessedTargetBits; |
| AI.TargetBitWidth = AccessBitsInFieldSize; |
| |
| AccessStart += AccessWidth; |
| AccessedTargetBits += AI.TargetBitWidth; |
| } |
| |
| assert(AccessedTargetBits == FieldSize && "Invalid bit-field access!"); |
| return CGBitFieldInfo(FieldSize, NumComponents, Components, IsSigned); |
| } |
| |
| CGBitFieldInfo CGBitFieldInfo::MakeInfo(CodeGenTypes &Types, |
| const FieldDecl *FD, |
| uint64_t FieldOffset, |
| uint64_t FieldSize) { |
| const RecordDecl *RD = FD->getParent(); |
| const ASTRecordLayout &RL = Types.getContext().getASTRecordLayout(RD); |
| uint64_t ContainingTypeSizeInBits = RL.getSize(); |
| unsigned ContainingTypeAlign = RL.getAlignment(); |
| |
| return MakeInfo(Types, FD, FieldOffset, FieldSize, ContainingTypeSizeInBits, |
| ContainingTypeAlign); |
| } |
| |
| void CGRecordLayoutBuilder::LayoutBitField(const FieldDecl *D, |
| uint64_t FieldOffset) { |
| uint64_t FieldSize = |
| D->getBitWidth()->EvaluateAsInt(Types.getContext()).getZExtValue(); |
| |
| if (FieldSize == 0) |
| return; |
| |
| uint64_t NextFieldOffset = NextFieldOffsetInBytes * 8; |
| unsigned NumBytesToAppend; |
| |
| if (FieldOffset < NextFieldOffset) { |
| assert(BitsAvailableInLastField && "Bitfield size mismatch!"); |
| assert(NextFieldOffsetInBytes && "Must have laid out at least one byte!"); |
| |
| // The bitfield begins in the previous bit-field. |
| NumBytesToAppend = |
| llvm::RoundUpToAlignment(FieldSize - BitsAvailableInLastField, 8) / 8; |
| } else { |
| assert(FieldOffset % 8 == 0 && "Field offset not aligned correctly"); |
| |
| // Append padding if necessary. |
| AppendBytes((FieldOffset - NextFieldOffset) / 8); |
| |
| NumBytesToAppend = |
| llvm::RoundUpToAlignment(FieldSize, 8) / 8; |
| |
| assert(NumBytesToAppend && "No bytes to append!"); |
| } |
| |
| // Add the bit field info. |
| LLVMBitFields.push_back( |
| LLVMBitFieldInfo(D, CGBitFieldInfo::MakeInfo(Types, D, FieldOffset, |
| FieldSize))); |
| |
| AppendBytes(NumBytesToAppend); |
| |
| BitsAvailableInLastField = |
| NextFieldOffsetInBytes * 8 - (FieldOffset + FieldSize); |
| } |
| |
| bool CGRecordLayoutBuilder::LayoutField(const FieldDecl *D, |
| uint64_t FieldOffset) { |
| // If the field is packed, then we need a packed struct. |
| if (!Packed && D->hasAttr<PackedAttr>()) |
| return false; |
| |
| if (D->isBitField()) { |
| // We must use packed structs for unnamed bit fields since they |
| // don't affect the struct alignment. |
| if (!Packed && !D->getDeclName()) |
| return false; |
| |
| LayoutBitField(D, FieldOffset); |
| return true; |
| } |
| |
| CheckZeroInitializable(D->getType()); |
| |
| assert(FieldOffset % 8 == 0 && "FieldOffset is not on a byte boundary!"); |
| uint64_t FieldOffsetInBytes = FieldOffset / 8; |
| |
| const llvm::Type *Ty = Types.ConvertTypeForMemRecursive(D->getType()); |
| unsigned TypeAlignment = getTypeAlignment(Ty); |
| |
| // If the type alignment is larger then the struct alignment, we must use |
| // a packed struct. |
| if (TypeAlignment > Alignment) { |
| assert(!Packed && "Alignment is wrong even with packed struct!"); |
| return false; |
| } |
| |
| if (const RecordType *RT = D->getType()->getAs<RecordType>()) { |
| const RecordDecl *RD = cast<RecordDecl>(RT->getDecl()); |
| if (const MaxFieldAlignmentAttr *MFAA = |
| RD->getAttr<MaxFieldAlignmentAttr>()) { |
| if (MFAA->getAlignment() != TypeAlignment * 8 && !Packed) |
| return false; |
| } |
| } |
| |
| // Round up the field offset to the alignment of the field type. |
| uint64_t AlignedNextFieldOffsetInBytes = |
| llvm::RoundUpToAlignment(NextFieldOffsetInBytes, TypeAlignment); |
| |
| if (FieldOffsetInBytes < AlignedNextFieldOffsetInBytes) { |
| assert(!Packed && "Could not place field even with packed struct!"); |
| return false; |
| } |
| |
| if (AlignedNextFieldOffsetInBytes < FieldOffsetInBytes) { |
| // Even with alignment, the field offset is not at the right place, |
| // insert padding. |
| uint64_t PaddingInBytes = FieldOffsetInBytes - NextFieldOffsetInBytes; |
| |
| AppendBytes(PaddingInBytes); |
| } |
| |
| // Now append the field. |
| LLVMFields.push_back(LLVMFieldInfo(D, FieldTypes.size())); |
| AppendField(FieldOffsetInBytes, Ty); |
| |
| return true; |
| } |
| |
| const llvm::Type * |
| CGRecordLayoutBuilder::LayoutUnionField(const FieldDecl *Field, |
| const ASTRecordLayout &Layout) { |
| if (Field->isBitField()) { |
| uint64_t FieldSize = |
| Field->getBitWidth()->EvaluateAsInt(Types.getContext()).getZExtValue(); |
| |
| // Ignore zero sized bit fields. |
| if (FieldSize == 0) |
| return 0; |
| |
| const llvm::Type *FieldTy = llvm::Type::getInt8Ty(Types.getLLVMContext()); |
| unsigned NumBytesToAppend = |
| llvm::RoundUpToAlignment(FieldSize, 8) / 8; |
| |
| if (NumBytesToAppend > 1) |
| FieldTy = llvm::ArrayType::get(FieldTy, NumBytesToAppend); |
| |
| // Add the bit field info. |
| LLVMBitFields.push_back( |
| LLVMBitFieldInfo(Field, CGBitFieldInfo::MakeInfo(Types, Field, |
| 0, FieldSize))); |
| return FieldTy; |
| } |
| |
| // This is a regular union field. |
| LLVMFields.push_back(LLVMFieldInfo(Field, 0)); |
| return Types.ConvertTypeForMemRecursive(Field->getType()); |
| } |
| |
| void CGRecordLayoutBuilder::LayoutUnion(const RecordDecl *D) { |
| assert(D->isUnion() && "Can't call LayoutUnion on a non-union record!"); |
| |
| const ASTRecordLayout &Layout = Types.getContext().getASTRecordLayout(D); |
| |
| const llvm::Type *Ty = 0; |
| uint64_t Size = 0; |
| unsigned Align = 0; |
| |
| bool HasOnlyZeroSizedBitFields = true; |
| |
| unsigned FieldNo = 0; |
| for (RecordDecl::field_iterator Field = D->field_begin(), |
| FieldEnd = D->field_end(); Field != FieldEnd; ++Field, ++FieldNo) { |
| assert(Layout.getFieldOffset(FieldNo) == 0 && |
| "Union field offset did not start at the beginning of record!"); |
| const llvm::Type *FieldTy = LayoutUnionField(*Field, Layout); |
| |
| if (!FieldTy) |
| continue; |
| |
| HasOnlyZeroSizedBitFields = false; |
| |
| unsigned FieldAlign = Types.getTargetData().getABITypeAlignment(FieldTy); |
| uint64_t FieldSize = Types.getTargetData().getTypeAllocSize(FieldTy); |
| |
| if (FieldAlign < Align) |
| continue; |
| |
| if (FieldAlign > Align || FieldSize > Size) { |
| Ty = FieldTy; |
| Align = FieldAlign; |
| Size = FieldSize; |
| } |
| } |
| |
| // Now add our field. |
| if (Ty) { |
| AppendField(0, Ty); |
| |
| if (getTypeAlignment(Ty) > Layout.getAlignment() / 8) { |
| // We need a packed struct. |
| Packed = true; |
| Align = 1; |
| } |
| } |
| if (!Align) { |
| assert(HasOnlyZeroSizedBitFields && |
| "0-align record did not have all zero-sized bit-fields!"); |
| Align = 1; |
| } |
| |
| // Append tail padding. |
| if (Layout.getSize() / 8 > Size) |
| AppendPadding(Layout.getSize() / 8, Align); |
| } |
| |
| void CGRecordLayoutBuilder::LayoutNonVirtualBase(const CXXRecordDecl *BaseDecl, |
| uint64_t BaseOffset) { |
| // Ignore empty bases. |
| if (BaseDecl->isEmpty()) |
| return; |
| |
| CheckZeroInitializable(BaseDecl); |
| |
| const ASTRecordLayout &Layout = |
| Types.getContext().getASTRecordLayout(BaseDecl); |
| |
| uint64_t NonVirtualSize = Layout.getNonVirtualSize(); |
| |
| // FIXME: Actually use a better type than [sizeof(BaseDecl) x i8] when we can. |
| AppendPadding(BaseOffset / 8, 1); |
| |
| // Append the base field. |
| LLVMNonVirtualBases.push_back(LLVMBaseInfo(BaseDecl, FieldTypes.size())); |
| |
| AppendBytes(NonVirtualSize / 8); |
| } |
| |
| void |
| CGRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD, |
| const ASTRecordLayout &Layout) { |
| const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase(); |
| |
| // Check if we need to add a vtable pointer. |
| if (RD->isDynamicClass()) { |
| if (!PrimaryBase) { |
| const llvm::Type *FunctionType = |
| llvm::FunctionType::get(llvm::Type::getInt32Ty(Types.getLLVMContext()), |
| /*isVarArg=*/true); |
| const llvm::Type *VTableTy = FunctionType->getPointerTo(); |
| |
| assert(NextFieldOffsetInBytes == 0 && |
| "VTable pointer must come first!"); |
| AppendField(NextFieldOffsetInBytes, VTableTy->getPointerTo()); |
| } else { |
| // FIXME: Handle a virtual primary base. |
| if (!Layout.getPrimaryBaseWasVirtual()) |
| LayoutNonVirtualBase(PrimaryBase, 0); |
| } |
| } |
| |
| // Layout the non-virtual bases. |
| for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), |
| E = RD->bases_end(); I != E; ++I) { |
| if (I->isVirtual()) |
| continue; |
| |
| const CXXRecordDecl *BaseDecl = |
| cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl()); |
| |
| // We've already laid out the primary base. |
| if (BaseDecl == PrimaryBase && !Layout.getPrimaryBaseWasVirtual()) |
| continue; |
| |
| LayoutNonVirtualBase(BaseDecl, Layout.getBaseClassOffsetInBits(BaseDecl)); |
| } |
| } |
| |
| void |
| CGRecordLayoutBuilder::ComputeNonVirtualBaseType(const CXXRecordDecl *RD) { |
| const ASTRecordLayout &Layout = Types.getContext().getASTRecordLayout(RD); |
| |
| uint64_t AlignedNonVirtualTypeSize = |
| llvm::RoundUpToAlignment(Layout.getNonVirtualSize(), |
| Layout.getNonVirtualAlign()) / 8; |
| |
| |
| // First check if we can use the same fields as for the complete class. |
| if (AlignedNonVirtualTypeSize == Layout.getSize() / 8) { |
| NonVirtualBaseTypeIsSameAsCompleteType = true; |
| return; |
| } |
| |
| NonVirtualBaseFieldTypes = FieldTypes; |
| |
| // Check if we need padding. |
| uint64_t AlignedNextFieldOffset = |
| llvm::RoundUpToAlignment(NextFieldOffsetInBytes, AlignmentAsLLVMStruct); |
| |
| assert(AlignedNextFieldOffset <= AlignedNonVirtualTypeSize && |
| "Size mismatch!"); |
| |
| if (AlignedNonVirtualTypeSize == AlignedNextFieldOffset) { |
| // We don't need any padding. |
| return; |
| } |
| |
| uint64_t NumBytes = AlignedNonVirtualTypeSize - AlignedNextFieldOffset; |
| NonVirtualBaseFieldTypes.push_back(getByteArrayType(NumBytes)); |
| } |
| |
| bool CGRecordLayoutBuilder::LayoutFields(const RecordDecl *D) { |
| assert(!D->isUnion() && "Can't call LayoutFields on a union!"); |
| assert(Alignment && "Did not set alignment!"); |
| |
| const ASTRecordLayout &Layout = Types.getContext().getASTRecordLayout(D); |
| |
| const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D); |
| if (RD) |
| LayoutNonVirtualBases(RD, Layout); |
| |
| unsigned FieldNo = 0; |
| |
| for (RecordDecl::field_iterator Field = D->field_begin(), |
| FieldEnd = D->field_end(); Field != FieldEnd; ++Field, ++FieldNo) { |
| if (!LayoutField(*Field, Layout.getFieldOffset(FieldNo))) { |
| assert(!Packed && |
| "Could not layout fields even with a packed LLVM struct!"); |
| return false; |
| } |
| } |
| |
| // We've laid out the non-virtual bases and the fields, now compute the |
| // non-virtual base field types. |
| if (RD) |
| ComputeNonVirtualBaseType(RD); |
| |
| // FIXME: Lay out the virtual bases instead of just treating them as tail |
| // padding. |
| |
| // Append tail padding if necessary. |
| AppendTailPadding(Layout.getSize()); |
| |
| return true; |
| } |
| |
| void CGRecordLayoutBuilder::AppendTailPadding(uint64_t RecordSize) { |
| assert(RecordSize % 8 == 0 && "Invalid record size!"); |
| |
| uint64_t RecordSizeInBytes = RecordSize / 8; |
| assert(NextFieldOffsetInBytes <= RecordSizeInBytes && "Size mismatch!"); |
| |
| uint64_t AlignedNextFieldOffset = |
| llvm::RoundUpToAlignment(NextFieldOffsetInBytes, AlignmentAsLLVMStruct); |
| |
| if (AlignedNextFieldOffset == RecordSizeInBytes) { |
| // We don't need any padding. |
| return; |
| } |
| |
| unsigned NumPadBytes = RecordSizeInBytes - NextFieldOffsetInBytes; |
| AppendBytes(NumPadBytes); |
| } |
| |
| void CGRecordLayoutBuilder::AppendField(uint64_t FieldOffsetInBytes, |
| const llvm::Type *FieldTy) { |
| AlignmentAsLLVMStruct = std::max(AlignmentAsLLVMStruct, |
| getTypeAlignment(FieldTy)); |
| |
| uint64_t FieldSizeInBytes = Types.getTargetData().getTypeAllocSize(FieldTy); |
| |
| FieldTypes.push_back(FieldTy); |
| |
| NextFieldOffsetInBytes = FieldOffsetInBytes + FieldSizeInBytes; |
| BitsAvailableInLastField = 0; |
| } |
| |
| void CGRecordLayoutBuilder::AppendPadding(uint64_t FieldOffsetInBytes, |
| unsigned FieldAlignment) { |
| assert(NextFieldOffsetInBytes <= FieldOffsetInBytes && |
| "Incorrect field layout!"); |
| |
| // Round up the field offset to the alignment of the field type. |
| uint64_t AlignedNextFieldOffsetInBytes = |
| llvm::RoundUpToAlignment(NextFieldOffsetInBytes, FieldAlignment); |
| |
| if (AlignedNextFieldOffsetInBytes < FieldOffsetInBytes) { |
| // Even with alignment, the field offset is not at the right place, |
| // insert padding. |
| uint64_t PaddingInBytes = FieldOffsetInBytes - NextFieldOffsetInBytes; |
| |
| AppendBytes(PaddingInBytes); |
| } |
| } |
| |
| const llvm::Type *CGRecordLayoutBuilder::getByteArrayType(uint64_t NumBytes) { |
| assert(NumBytes != 0 && "Empty byte array's aren't allowed."); |
| |
| const llvm::Type *Ty = llvm::Type::getInt8Ty(Types.getLLVMContext()); |
| if (NumBytes > 1) |
| Ty = llvm::ArrayType::get(Ty, NumBytes); |
| |
| return Ty; |
| } |
| |
| void CGRecordLayoutBuilder::AppendBytes(uint64_t NumBytes) { |
| if (NumBytes == 0) |
| return; |
| |
| // Append the padding field |
| AppendField(NextFieldOffsetInBytes, getByteArrayType(NumBytes)); |
| } |
| |
| unsigned CGRecordLayoutBuilder::getTypeAlignment(const llvm::Type *Ty) const { |
| if (Packed) |
| return 1; |
| |
| return Types.getTargetData().getABITypeAlignment(Ty); |
| } |
| |
| const CGRecordLayout & |
| CGRecordLayoutBuilder::getCGRecordLayout(const CXXRecordDecl *RD) { |
| // FIXME: It would be better if there was a way to explicitly compute the |
| // record layout instead of converting to a type. |
| Types.ConvertTagDeclType(RD); |
| |
| return Types.getCGRecordLayout(RD); |
| } |
| |
| void CGRecordLayoutBuilder::CheckZeroInitializable(QualType T) { |
| // This record already contains a member pointer. |
| if (!IsZeroInitializable) |
| return; |
| |
| // Can only have member pointers if we're compiling C++. |
| if (!Types.getContext().getLangOptions().CPlusPlus) |
| return; |
| |
| T = Types.getContext().getBaseElementType(T); |
| |
| if (const MemberPointerType *MPT = T->getAs<MemberPointerType>()) { |
| if (!Types.getCXXABI().isZeroInitializable(MPT)) |
| IsZeroInitializable = false; |
| } else if (const RecordType *RT = T->getAs<RecordType>()) { |
| const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); |
| CheckZeroInitializable(RD); |
| } |
| } |
| |
| void CGRecordLayoutBuilder::CheckZeroInitializable(const CXXRecordDecl *RD) { |
| // This record already contains a member pointer. |
| if (!IsZeroInitializable) |
| return; |
| |
| const CGRecordLayout &Layout = getCGRecordLayout(RD); |
| if (!Layout.isZeroInitializable()) |
| IsZeroInitializable = false; |
| } |
| |
| CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D) { |
| CGRecordLayoutBuilder Builder(*this); |
| |
| Builder.Layout(D); |
| |
| const llvm::StructType *Ty = llvm::StructType::get(getLLVMContext(), |
| Builder.FieldTypes, |
| Builder.Packed); |
| |
| const llvm::StructType *BaseTy = 0; |
| if (isa<CXXRecordDecl>(D)) { |
| if (Builder.NonVirtualBaseTypeIsSameAsCompleteType) |
| BaseTy = Ty; |
| else if (!Builder.NonVirtualBaseFieldTypes.empty()) |
| BaseTy = llvm::StructType::get(getLLVMContext(), |
| Builder.NonVirtualBaseFieldTypes, |
| Builder.Packed); |
| } |
| |
| CGRecordLayout *RL = |
| new CGRecordLayout(Ty, BaseTy, Builder.IsZeroInitializable); |
| |
| // Add all the non-virtual base field numbers. |
| RL->NonVirtualBaseFields.insert(Builder.LLVMNonVirtualBases.begin(), |
| Builder.LLVMNonVirtualBases.end()); |
| |
| // Add all the field numbers. |
| RL->FieldInfo.insert(Builder.LLVMFields.begin(), |
| Builder.LLVMFields.end()); |
| |
| // Add bitfield info. |
| RL->BitFields.insert(Builder.LLVMBitFields.begin(), |
| Builder.LLVMBitFields.end()); |
| |
| // Dump the layout, if requested. |
| if (getContext().getLangOptions().DumpRecordLayouts) { |
| llvm::errs() << "\n*** Dumping IRgen Record Layout\n"; |
| llvm::errs() << "Record: "; |
| D->dump(); |
| llvm::errs() << "\nLayout: "; |
| RL->dump(); |
| } |
| |
| #ifndef NDEBUG |
| // Verify that the computed LLVM struct size matches the AST layout size. |
| const ASTRecordLayout &Layout = getContext().getASTRecordLayout(D); |
| |
| uint64_t TypeSizeInBits = Layout.getSize(); |
| assert(TypeSizeInBits == getTargetData().getTypeAllocSizeInBits(Ty) && |
| "Type size mismatch!"); |
| |
| if (BaseTy) { |
| uint64_t AlignedNonVirtualTypeSizeInBits = |
| llvm::RoundUpToAlignment(Layout.getNonVirtualSize(), |
| Layout.getNonVirtualAlign()); |
| |
| assert(AlignedNonVirtualTypeSizeInBits == |
| getTargetData().getTypeAllocSizeInBits(BaseTy) && |
| "Type size mismatch!"); |
| } |
| |
| // Verify that the LLVM and AST field offsets agree. |
| const llvm::StructType *ST = |
| dyn_cast<llvm::StructType>(RL->getLLVMType()); |
| const llvm::StructLayout *SL = getTargetData().getStructLayout(ST); |
| |
| const ASTRecordLayout &AST_RL = getContext().getASTRecordLayout(D); |
| RecordDecl::field_iterator it = D->field_begin(); |
| for (unsigned i = 0, e = AST_RL.getFieldCount(); i != e; ++i, ++it) { |
| const FieldDecl *FD = *it; |
| |
| // For non-bit-fields, just check that the LLVM struct offset matches the |
| // AST offset. |
| if (!FD->isBitField()) { |
| unsigned FieldNo = RL->getLLVMFieldNo(FD); |
| assert(AST_RL.getFieldOffset(i) == SL->getElementOffsetInBits(FieldNo) && |
| "Invalid field offset!"); |
| continue; |
| } |
| |
| // Ignore unnamed bit-fields. |
| if (!FD->getDeclName()) |
| continue; |
| |
| const CGBitFieldInfo &Info = RL->getBitFieldInfo(FD); |
| for (unsigned i = 0, e = Info.getNumComponents(); i != e; ++i) { |
| const CGBitFieldInfo::AccessInfo &AI = Info.getComponent(i); |
| |
| // Verify that every component access is within the structure. |
| uint64_t FieldOffset = SL->getElementOffsetInBits(AI.FieldIndex); |
| uint64_t AccessBitOffset = FieldOffset + AI.FieldByteOffset * 8; |
| assert(AccessBitOffset + AI.AccessWidth <= TypeSizeInBits && |
| "Invalid bit-field access (out of range)!"); |
| } |
| } |
| #endif |
| |
| return RL; |
| } |
| |
| void CGRecordLayout::print(llvm::raw_ostream &OS) const { |
| OS << "<CGRecordLayout\n"; |
| OS << " LLVMType:" << *LLVMType << "\n"; |
| if (NonVirtualBaseLLVMType) |
| OS << " NonVirtualBaseLLVMType:" << *NonVirtualBaseLLVMType << "\n"; |
| OS << " IsZeroInitializable:" << IsZeroInitializable << "\n"; |
| OS << " BitFields:[\n"; |
| |
| // Print bit-field infos in declaration order. |
| std::vector<std::pair<unsigned, const CGBitFieldInfo*> > BFIs; |
| for (llvm::DenseMap<const FieldDecl*, CGBitFieldInfo>::const_iterator |
| it = BitFields.begin(), ie = BitFields.end(); |
| it != ie; ++it) { |
| const RecordDecl *RD = it->first->getParent(); |
| unsigned Index = 0; |
| for (RecordDecl::field_iterator |
| it2 = RD->field_begin(); *it2 != it->first; ++it2) |
| ++Index; |
| BFIs.push_back(std::make_pair(Index, &it->second)); |
| } |
| llvm::array_pod_sort(BFIs.begin(), BFIs.end()); |
| for (unsigned i = 0, e = BFIs.size(); i != e; ++i) { |
| OS.indent(4); |
| BFIs[i].second->print(OS); |
| OS << "\n"; |
| } |
| |
| OS << "]>\n"; |
| } |
| |
| void CGRecordLayout::dump() const { |
| print(llvm::errs()); |
| } |
| |
| void CGBitFieldInfo::print(llvm::raw_ostream &OS) const { |
| OS << "<CGBitFieldInfo"; |
| OS << " Size:" << Size; |
| OS << " IsSigned:" << IsSigned << "\n"; |
| |
| OS.indent(4 + strlen("<CGBitFieldInfo")); |
| OS << " NumComponents:" << getNumComponents(); |
| OS << " Components: ["; |
| if (getNumComponents()) { |
| OS << "\n"; |
| for (unsigned i = 0, e = getNumComponents(); i != e; ++i) { |
| const AccessInfo &AI = getComponent(i); |
| OS.indent(8); |
| OS << "<AccessInfo" |
| << " FieldIndex:" << AI.FieldIndex |
| << " FieldByteOffset:" << AI.FieldByteOffset |
| << " FieldBitStart:" << AI.FieldBitStart |
| << " AccessWidth:" << AI.AccessWidth << "\n"; |
| OS.indent(8 + strlen("<AccessInfo")); |
| OS << " AccessAlignment:" << AI.AccessAlignment |
| << " TargetBitOffset:" << AI.TargetBitOffset |
| << " TargetBitWidth:" << AI.TargetBitWidth |
| << ">\n"; |
| } |
| OS.indent(4); |
| } |
| OS << "]>"; |
| } |
| |
| void CGBitFieldInfo::dump() const { |
| print(llvm::errs()); |
| } |