ELFAttribute.h revision f33f6de54db174aa679a4b6d1e040d37e95541c0
1//===- ELFAttribute.h -----------------------------------------------------===// 2// 3// The MCLinker Project 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9#ifndef MCLD_TARGET_ELFATTRIBUTE_H 10#define MCLD_TARGET_ELFATTRIBUTE_H 11#ifdef ENABLE_UNITTEST 12#include <gtest.h> 13#endif 14 15#include <mcld/Support/MemoryRegion.h> 16#include <mcld/Target/ELFAttributeData.h> 17 18#include <llvm/ADT/SmallVector.h> 19#include <llvm/ADT/StringRef.h> 20 21namespace mcld { 22 23class ELFAttributeData; 24class GNULDBackend; 25class Input; 26class LDSection; 27class LinkerConfig; 28 29/** \class ELFAttribute 30 * \brief ELFAttribute is the attribute section in an ELF file. 31 */ 32class ELFAttribute 33{ 34public: 35 // ARM [ABI-addenda], 2.2.3. 36 static const char FormatVersion = 'A'; 37 static const size_t FormatVersionFieldSize = sizeof(FormatVersion); // a byte 38 static const size_t SubsectionLengthFieldSize = 4; // a 4-byte integer 39 40 // MinimalELFAttributeSubsectionSize is the minimal number of bytes a valid 41 // subsection in ELF attribute section should have. 42 static const size_t MinimalELFAttributeSubsectionSize 43 = 1 /* Tag_File, see ARM [ABI-addenda], 2.2.4 */ + 44 4 /* byte-size, see ARM [ABI-addenda], 2.2.4 */; 45 46 // MinimalELFAttributeSectionSize is the minimal number of bytes a valid ELF 47 // attribute section should have. 48 static const size_t MinimalELFAttributeSectionSize 49 = FormatVersionFieldSize + SubsectionLengthFieldSize + 50 2 /* vendor-name, a char plus '\0', see ARM [ABI-addenda], 2.2.3 */ + 51 1 * MinimalELFAttributeSubsectionSize; 52 53public: 54 ELFAttribute(const GNULDBackend &pBackend, const LinkerConfig& pConfig) 55 : m_Backend(pBackend), m_Config(pConfig) { } 56 57 ~ELFAttribute(); 58 59public: 60 /// merge - merge attributes from input (attribute) section 61 bool merge(const Input &pInput, LDSection &pInputAttrSectHdr); 62 63 /// sizeOutput - calculate the number of bytes required to encode this 64 /// attribute data section 65 size_t sizeOutput() const; 66 67 /// emit - encode and write out this attribute section 68 size_t emit(MemoryRegion &pRegion) const; 69 70 inline const GNULDBackend &backend() const { return m_Backend; } 71 72 inline const LinkerConfig &config() const { return m_Config; } 73 74 // Place vendor's attribute data under the management. 75 void registerAttributeData(ELFAttributeData& pAttrData); 76 77private: 78 /** \class Subsection 79 * \brief A helper class to wrap ELFAttributeData and to provide general 80 * interfaces for ELFAttribute to operate on 81 */ 82 class Subsection { 83 public: 84 Subsection(ELFAttribute &pParent, ELFAttributeData &pAttrData) 85 : m_Parent(pParent), m_AttrData(pAttrData) { } 86 87 public: 88 bool isMyAttribute(llvm::StringRef pVendorName) const 89 { 90 return (m_AttrData.getVendorName() == pVendorName); 91 } 92 93 /// merge - Merge the attributes from the section in the input data. 94 bool merge(const Input &pInput, ConstAddress pData, size_t pSize); 95 96 /// sizeOutput - calculate the number of bytes required to encode this 97 /// subsection 98 size_t sizeOutput() const; 99 100 /// emit - write out this attribute subsection to the buffer. 101 size_t emit(char *pBuf) const; 102 103 private: 104 // The attribute section this subsection belongs to 105 ELFAttribute &m_Parent; 106 107 // The attribute data containing in this subsection 108 ELFAttributeData &m_AttrData; 109 }; 110 111 // Obtain the corresponding subsection of the specified vendor 112 Subsection *getSubsection(llvm::StringRef pVendorName) const; 113 114private: 115 const GNULDBackend &m_Backend; 116 117 const LinkerConfig &m_Config; 118 119 // There is at most two subsections ("aeabi" and "gnu") in most cases. 120 llvm::SmallVector<Subsection*, 2> m_Subsections; 121}; 122 123} // namespace of mcld 124 125#endif 126