1 //===-- llvm/MC/MCELFObjectWriter.h - ELF Object Writer ---------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 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 LLVM_MC_MCELFOBJECTWRITER_H 11 #define LLVM_MC_MCELFOBJECTWRITER_H 12 13 #include "llvm/ADT/Triple.h" 14 #include "llvm/Support/DataTypes.h" 15 #include "llvm/Support/ELF.h" 16 #include <vector> 17 18 namespace llvm { 19 class MCAssembler; 20 class MCFixup; 21 class MCFragment; 22 class MCObjectWriter; 23 class MCSymbol; 24 class MCValue; 25 26 /// @name Relocation Data 27 /// @{ 28 29 struct ELFRelocationEntry { 30 // Make these big enough for both 32-bit and 64-bit 31 uint64_t r_offset; 32 int Index; 33 unsigned Type; 34 const MCSymbol *Symbol; 35 uint64_t r_addend; 36 const MCFixup *Fixup; 37 38 ELFRelocationEntry() 39 : r_offset(0), Index(0), Type(0), Symbol(0), r_addend(0), Fixup(0) {} 40 41 ELFRelocationEntry(uint64_t RelocOffset, int Idx, unsigned RelType, 42 const MCSymbol *Sym, uint64_t Addend, const MCFixup &Fixup) 43 : r_offset(RelocOffset), Index(Idx), Type(RelType), Symbol(Sym), 44 r_addend(Addend), Fixup(&Fixup) {} 45 46 // Support lexicographic sorting. 47 bool operator<(const ELFRelocationEntry &RE) const { 48 return RE.r_offset < r_offset; 49 } 50 }; 51 52 class MCELFObjectTargetWriter { 53 const uint8_t OSABI; 54 const uint16_t EMachine; 55 const unsigned HasRelocationAddend : 1; 56 const unsigned Is64Bit : 1; 57 const unsigned IsN64 : 1; 58 59 protected: 60 61 MCELFObjectTargetWriter(bool Is64Bit_, uint8_t OSABI_, 62 uint16_t EMachine_, bool HasRelocationAddend, 63 bool IsN64=false); 64 65 public: 66 static uint8_t getOSABI(Triple::OSType OSType) { 67 switch (OSType) { 68 case Triple::FreeBSD: 69 return ELF::ELFOSABI_FREEBSD; 70 case Triple::Linux: 71 return ELF::ELFOSABI_LINUX; 72 default: 73 return ELF::ELFOSABI_NONE; 74 } 75 } 76 77 virtual ~MCELFObjectTargetWriter() {} 78 79 virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, 80 bool IsPCRel, bool IsRelocWithSymbol, 81 int64_t Addend) const = 0; 82 virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm, 83 const MCValue &Target, 84 const MCFragment &F, 85 const MCFixup &Fixup, 86 bool IsPCRel) const; 87 virtual const MCSymbol *undefinedExplicitRelSym(const MCValue &Target, 88 const MCFixup &Fixup, 89 bool IsPCRel) const; 90 virtual void adjustFixupOffset(const MCFixup &Fixup, 91 uint64_t &RelocOffset); 92 93 virtual void sortRelocs(const MCAssembler &Asm, 94 std::vector<ELFRelocationEntry> &Relocs); 95 96 /// @name Accessors 97 /// @{ 98 uint8_t getOSABI() const { return OSABI; } 99 uint16_t getEMachine() const { return EMachine; } 100 bool hasRelocationAddend() const { return HasRelocationAddend; } 101 bool is64Bit() const { return Is64Bit; } 102 bool isN64() const { return IsN64; } 103 /// @} 104 105 // Instead of changing everyone's API we pack the N64 Type fields 106 // into the existing 32 bit data unsigned. 107 #define R_TYPE_SHIFT 0 108 #define R_TYPE_MASK 0xffffff00 109 #define R_TYPE2_SHIFT 8 110 #define R_TYPE2_MASK 0xffff00ff 111 #define R_TYPE3_SHIFT 16 112 #define R_TYPE3_MASK 0xff00ffff 113 #define R_SSYM_SHIFT 24 114 #define R_SSYM_MASK 0x00ffffff 115 116 // N64 relocation type accessors 117 unsigned getRType(uint32_t Type) const { 118 return (unsigned)((Type >> R_TYPE_SHIFT) & 0xff); 119 } 120 unsigned getRType2(uint32_t Type) const { 121 return (unsigned)((Type >> R_TYPE2_SHIFT) & 0xff); 122 } 123 unsigned getRType3(uint32_t Type) const { 124 return (unsigned)((Type >> R_TYPE3_SHIFT) & 0xff); 125 } 126 unsigned getRSsym(uint32_t Type) const { 127 return (unsigned)((Type >> R_SSYM_SHIFT) & 0xff); 128 } 129 130 // N64 relocation type setting 131 unsigned setRType(unsigned Value, unsigned Type) const { 132 return ((Type & R_TYPE_MASK) | ((Value & 0xff) << R_TYPE_SHIFT)); 133 } 134 unsigned setRType2(unsigned Value, unsigned Type) const { 135 return (Type & R_TYPE2_MASK) | ((Value & 0xff) << R_TYPE2_SHIFT); 136 } 137 unsigned setRType3(unsigned Value, unsigned Type) const { 138 return (Type & R_TYPE3_MASK) | ((Value & 0xff) << R_TYPE3_SHIFT); 139 } 140 unsigned setRSsym(unsigned Value, unsigned Type) const { 141 return (Type & R_SSYM_MASK) | ((Value & 0xff) << R_SSYM_SHIFT); 142 } 143 }; 144 145 /// \brief Construct a new ELF writer instance. 146 /// 147 /// \param MOTW - The target specific ELF writer subclass. 148 /// \param OS - The stream to write to. 149 /// \returns The constructed object writer. 150 MCObjectWriter *createELFObjectWriter(MCELFObjectTargetWriter *MOTW, 151 raw_ostream &OS, bool IsLittleEndian); 152 } // End llvm namespace 153 154 #endif 155