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