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 ELFRelocationEntryELFRelocationEntry38 ELFRelocationEntry() 39 : r_offset(0), Index(0), Type(0), Symbol(0), r_addend(0), Fixup(0) {} 40 ELFRelocationEntryELFRelocationEntry41 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 47 class MCELFObjectTargetWriter { 48 const uint8_t OSABI; 49 const uint16_t EMachine; 50 const unsigned HasRelocationAddend : 1; 51 const unsigned Is64Bit : 1; 52 const unsigned IsN64 : 1; 53 54 protected: 55 56 MCELFObjectTargetWriter(bool Is64Bit_, uint8_t OSABI_, 57 uint16_t EMachine_, bool HasRelocationAddend, 58 bool IsN64=false); 59 60 public: getOSABI(Triple::OSType OSType)61 static uint8_t getOSABI(Triple::OSType OSType) { 62 switch (OSType) { 63 case Triple::FreeBSD: 64 return ELF::ELFOSABI_FREEBSD; 65 case Triple::Linux: 66 return ELF::ELFOSABI_LINUX; 67 default: 68 return ELF::ELFOSABI_NONE; 69 } 70 } 71 ~MCELFObjectTargetWriter()72 virtual ~MCELFObjectTargetWriter() {} 73 74 virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, 75 bool IsPCRel, bool IsRelocWithSymbol, 76 int64_t Addend) const = 0; 77 virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm, 78 const MCValue &Target, 79 const MCFragment &F, 80 const MCFixup &Fixup, 81 bool IsPCRel) const; 82 virtual const MCSymbol *undefinedExplicitRelSym(const MCValue &Target, 83 const MCFixup &Fixup, 84 bool IsPCRel) const; 85 86 virtual void sortRelocs(const MCAssembler &Asm, 87 std::vector<ELFRelocationEntry> &Relocs); 88 89 /// @name Accessors 90 /// @{ getOSABI()91 uint8_t getOSABI() const { return OSABI; } getEMachine()92 uint16_t getEMachine() const { return EMachine; } hasRelocationAddend()93 bool hasRelocationAddend() const { return HasRelocationAddend; } is64Bit()94 bool is64Bit() const { return Is64Bit; } isN64()95 bool isN64() const { return IsN64; } 96 /// @} 97 98 // Instead of changing everyone's API we pack the N64 Type fields 99 // into the existing 32 bit data unsigned. 100 #define R_TYPE_SHIFT 0 101 #define R_TYPE_MASK 0xffffff00 102 #define R_TYPE2_SHIFT 8 103 #define R_TYPE2_MASK 0xffff00ff 104 #define R_TYPE3_SHIFT 16 105 #define R_TYPE3_MASK 0xff00ffff 106 #define R_SSYM_SHIFT 24 107 #define R_SSYM_MASK 0x00ffffff 108 109 // N64 relocation type accessors getRType(uint32_t Type)110 unsigned getRType(uint32_t Type) const { 111 return (unsigned)((Type >> R_TYPE_SHIFT) & 0xff); 112 } getRType2(uint32_t Type)113 unsigned getRType2(uint32_t Type) const { 114 return (unsigned)((Type >> R_TYPE2_SHIFT) & 0xff); 115 } getRType3(uint32_t Type)116 unsigned getRType3(uint32_t Type) const { 117 return (unsigned)((Type >> R_TYPE3_SHIFT) & 0xff); 118 } getRSsym(uint32_t Type)119 unsigned getRSsym(uint32_t Type) const { 120 return (unsigned)((Type >> R_SSYM_SHIFT) & 0xff); 121 } 122 123 // N64 relocation type setting setRType(unsigned Value,unsigned Type)124 unsigned setRType(unsigned Value, unsigned Type) const { 125 return ((Type & R_TYPE_MASK) | ((Value & 0xff) << R_TYPE_SHIFT)); 126 } setRType2(unsigned Value,unsigned Type)127 unsigned setRType2(unsigned Value, unsigned Type) const { 128 return (Type & R_TYPE2_MASK) | ((Value & 0xff) << R_TYPE2_SHIFT); 129 } setRType3(unsigned Value,unsigned Type)130 unsigned setRType3(unsigned Value, unsigned Type) const { 131 return (Type & R_TYPE3_MASK) | ((Value & 0xff) << R_TYPE3_SHIFT); 132 } setRSsym(unsigned Value,unsigned Type)133 unsigned setRSsym(unsigned Value, unsigned Type) const { 134 return (Type & R_SSYM_MASK) | ((Value & 0xff) << R_SSYM_SHIFT); 135 } 136 }; 137 138 /// \brief Construct a new ELF writer instance. 139 /// 140 /// \param MOTW - The target specific ELF writer subclass. 141 /// \param OS - The stream to write to. 142 /// \returns The constructed object writer. 143 MCObjectWriter *createELFObjectWriter(MCELFObjectTargetWriter *MOTW, 144 raw_ostream &OS, bool IsLittleEndian); 145 } // End llvm namespace 146 147 #endif 148