forked from OSchip/llvm-project
124 lines
4.2 KiB
C++
124 lines
4.2 KiB
C++
//===--- CGRecordLayoutBuilder.h - Record builder helper --------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This is a helper class used to build CGRecordLayout objects and LLVM types.
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//
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//===----------------------------------------------------------------------===//
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#ifndef CLANG_CODEGEN_CGRECORDLAYOUTBUILDER_H
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#define CLANG_CODEGEN_CGRECORDLAYOUTBUILDER_H
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/DataTypes.h"
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#include <vector>
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namespace llvm {
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class Type;
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}
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namespace clang {
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class FieldDecl;
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class RecordDecl;
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namespace CodeGen {
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class CGRecordLayout;
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class CodeGenTypes;
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class CGRecordLayoutBuilder {
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CodeGenTypes &Types;
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/// Packed - Whether the resulting LLVM struct will be packed or not.
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bool Packed;
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/// AlignmentAsLLVMStruct - Will contain the maximum alignment of all the
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/// LLVM types.
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unsigned AlignmentAsLLVMStruct;
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/// BitsAvailableInLastField - If a bit field spans only part of a LLVM field,
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/// this will have the number of bits still available in the field.
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char BitsAvailableInLastField;
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/// NextFieldOffsetInBytes - Holds the next field offset in bytes.
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uint64_t NextFieldOffsetInBytes;
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/// FieldTypes - Holds the LLVM types that the struct is created from.
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std::vector<const llvm::Type *> FieldTypes;
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/// LLVMFieldInfo - Holds a field and its corresponding LLVM field number.
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typedef std::pair<const FieldDecl *, unsigned> LLVMFieldInfo;
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llvm::SmallVector<LLVMFieldInfo, 16> LLVMFields;
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/// LLVMBitFieldInfo - Holds location and size information about a bit field.
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struct LLVMBitFieldInfo {
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LLVMBitFieldInfo(const FieldDecl *FD, unsigned FieldNo, unsigned Start,
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unsigned Size)
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: FD(FD), FieldNo(FieldNo), Start(Start), Size(Size) { }
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const FieldDecl *FD;
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unsigned FieldNo;
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unsigned Start;
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unsigned Size;
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};
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llvm::SmallVector<LLVMBitFieldInfo, 16> LLVMBitFields;
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CGRecordLayoutBuilder(CodeGenTypes &Types)
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: Types(Types), Packed(false), AlignmentAsLLVMStruct(1)
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, BitsAvailableInLastField(0), NextFieldOffsetInBytes(0) { }
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/// Layout - Will layout a RecordDecl.
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void Layout(const RecordDecl *D);
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/// LayoutUnion - Will layout a union RecordDecl.
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void LayoutUnion(const RecordDecl *D);
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/// LayoutField - try to layout all fields in the record decl.
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/// Returns false if the operation failed because the struct is not packed.
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bool LayoutFields(const RecordDecl *D);
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/// LayoutField - layout a single field. Returns false if the operation failed
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/// because the current struct is not packed.
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bool LayoutField(const FieldDecl *D, uint64_t FieldOffset);
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/// LayoutBitField - layout a single bit field.
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void LayoutBitField(const FieldDecl *D, uint64_t FieldOffset);
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/// AppendField - Appends a field with the given offset and type.
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void AppendField(uint64_t FieldOffsetInBytes, const llvm::Type *FieldTy);
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/// AppendPadding - Appends enough padding bytes so that the total struct
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/// size matches the alignment of the passed in type.
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void AppendPadding(uint64_t FieldOffsetInBytes, const llvm::Type *FieldTy);
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/// AppendPadding - Appends enough padding bytes so that the total
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/// struct size is a multiple of the field alignment.
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void AppendPadding(uint64_t FieldOffsetInBytes, unsigned FieldAlignment);
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/// AppendBytes - Append a given number of bytes to the record.
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void AppendBytes(uint64_t NumBytes);
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/// AppendTailPadding - Append enough tail padding so that the type will have
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/// the passed size.
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void AppendTailPadding(uint64_t RecordSize);
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unsigned getTypeAlignment(const llvm::Type *Ty) const;
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uint64_t getTypeSizeInBytes(const llvm::Type *Ty) const;
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public:
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/// ComputeLayout - Return the right record layout for a given record decl.
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static CGRecordLayout *ComputeLayout(CodeGenTypes &Types,
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const RecordDecl *D);
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};
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} // end namespace CodeGen
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} // end namespace clang
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#endif
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