1 //===- LDSection.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 10 #ifndef MCLD_LD_LDSECTION_H 11 #define MCLD_LD_LDSECTION_H 12 13 #include <llvm/Support/DataTypes.h> 14 #include <mcld/Support/Allocators.h> 15 #include <mcld/Config/Config.h> 16 #include <mcld/LD/LDFileFormat.h> 17 #include <string> 18 19 namespace mcld { 20 21 class SectionData; 22 class RelocData; 23 class EhFrame; 24 25 /** \class LDSection 26 * \brief LDSection represents a section header entry. It is a unified 27 * abstraction of a section header entry for various file formats. 28 */ 29 class LDSection 30 { 31 private: 32 friend class Chunk<LDSection, MCLD_SECTIONS_PER_INPUT>; 33 34 LDSection(); 35 36 LDSection(const std::string& pName, 37 LDFileFormat::Kind pKind, 38 uint32_t pType, 39 uint32_t pFlag, 40 uint64_t pSize = 0, 41 uint64_t pAddr = 0); 42 43 public: 44 ~LDSection(); 45 46 static LDSection* Create(const std::string& pName, 47 LDFileFormat::Kind pKind, 48 uint32_t pType, 49 uint32_t pFlag, 50 uint64_t pSize = 0, 51 uint64_t pAddr = 0); 52 53 static void Destroy(LDSection*& pSection); 54 55 static void Clear(); 56 57 bool hasOffset() const; 58 59 /// name - the name of this section. 60 const std::string& name() const 61 { return m_Name; } 62 63 /// kind - the kind of this section, such as Text, BSS, GOT, and so on. 64 /// from LDFileFormat::Kind 65 LDFileFormat::Kind kind() const 66 { return m_Kind; } 67 68 /// type - The categorizes the section's contents and semantics. It's 69 /// different from llvm::SectionKind. Type is format-dependent, but 70 /// llvm::SectionKind is format independent and is used for bit-code. 71 /// In ELF, it is sh_type 72 /// In MachO, it's type field of struct section::flags 73 uint32_t type() const 74 { return m_Type; } 75 76 /// flag - An integer describes miscellaneous attributes. 77 /// In ELF, it is sh_flags. 78 /// In MachO, it's attribute field of struct section::flags 79 uint32_t flag() const 80 { return m_Flag; } 81 82 /// size - An integer specifying the size in bytes of the virtual memory 83 /// occupied by this section. 84 /// In ELF, if the type() is SHT_NOBITS, this function return zero. 85 /// Before layouting, output's LDSection::size() should return zero. 86 uint64_t size() const 87 { return m_Size; } 88 89 /// offset - An integer specifying the offset of this section in the file. 90 /// Before layouting, output's LDSection::offset() should return zero. 91 uint64_t offset() const 92 { return m_Offset; } 93 94 /// addr - An integer specifying the virtual address of this section in the 95 /// virtual image. 96 /// Before layouting, output's LDSection::offset() should return zero. 97 /// ELF uses sh_addralign to set alignment constraints. In LLVM, alignment 98 /// constraint is set in SectionData::setAlignment. addr() contains the 99 /// original ELF::sh_addr. Modulo sh_addr by sh_addralign is not necessary. 100 /// MachO uses the same scenario. 101 /// 102 /// Because addr() in output is changing during linking, MCLinker does not 103 /// store the address of the output here. The address is in Layout 104 uint64_t addr() const 105 { return m_Addr; } 106 107 /// align - An integer specifying the align of this section in the file. 108 /// Before layouting, output's LDSection::align() should return zero. 109 uint32_t align() const 110 { return m_Align; } 111 112 size_t index() const 113 { return m_Index; } 114 115 /// getLink - return the Link. When a section A needs the other section B 116 /// during linking or loading, we say B is A's Link section. 117 /// In ELF, InfoLink section control the ElfNN_Shdr::sh_link and sh_info. 118 /// 119 /// @return if the section needs no other sections, return NULL 120 LDSection* getLink() 121 { return m_pLink; } 122 123 const LDSection* getLink() const 124 { return m_pLink; } 125 126 size_t getInfo() const 127 { return m_Info; } 128 129 void setKind(LDFileFormat::Kind pKind) 130 { m_Kind = pKind; } 131 132 void setSize(uint64_t size) 133 { m_Size = size; } 134 135 void setOffset(uint64_t Offset) 136 { m_Offset = Offset; } 137 138 void setAddr(uint64_t addr) 139 { m_Addr = addr; } 140 141 void setAlign(uint32_t align) 142 { m_Align = align; } 143 144 void setFlag(uint32_t flag) 145 { m_Flag = flag; } 146 147 void setType(uint32_t type) 148 { m_Type = type; } 149 150 // ----- SectionData ----- // 151 const SectionData* getSectionData() const { return m_Data.sect_data; } 152 SectionData* getSectionData() { return m_Data.sect_data; } 153 154 void setSectionData(SectionData* pSD) { m_Data.sect_data = pSD; } 155 156 bool hasSectionData() const; 157 158 // ------ RelocData ------ // 159 const RelocData* getRelocData() const { return m_Data.reloc_data; } 160 RelocData* getRelocData() { return m_Data.reloc_data; } 161 162 void setRelocData(RelocData* pRD) { m_Data.reloc_data = pRD; } 163 164 bool hasRelocData() const; 165 166 // ------ EhFrame ------ // 167 const EhFrame* getEhFrame() const { return m_Data.eh_frame; } 168 EhFrame* getEhFrame() { return m_Data.eh_frame; } 169 170 void setEhFrame(EhFrame* pEhFrame) { m_Data.eh_frame = pEhFrame; } 171 172 bool hasEhFrame() const; 173 174 /// setLink - set the sections should link with. 175 /// if pLink is NULL, no Link section is set. 176 void setLink(LDSection* pLink) 177 { m_pLink = pLink; } 178 179 void setInfo(size_t pInfo) 180 { m_Info = pInfo; } 181 182 void setIndex(size_t pIndex) 183 { m_Index = pIndex; } 184 185 private: 186 union SectOrRelocData 187 { 188 SectionData* sect_data; 189 RelocData* reloc_data; 190 EhFrame* eh_frame; 191 }; 192 193 private: 194 std::string m_Name; 195 196 LDFileFormat::Kind m_Kind; 197 uint32_t m_Type; 198 uint32_t m_Flag; 199 200 uint64_t m_Size; 201 uint64_t m_Offset; 202 uint64_t m_Addr; 203 uint32_t m_Align; 204 205 size_t m_Info; 206 LDSection* m_pLink; 207 208 /// m_Data - the SectionData or RelocData of this section 209 SectOrRelocData m_Data; 210 211 /// m_Index - the index of the file 212 size_t m_Index; 213 214 }; // end of LDSection 215 216 } // end namespace mcld 217 218 #endif 219 220
