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/MC/MCValue.h" 15 #include "llvm/Support/DataTypes.h" 16 #include "llvm/Support/ELF.h" 17 #include "llvm/Support/raw_ostream.h" 18 #include <vector> 19 20 namespace llvm { 21 class MCAssembler; 22 class MCContext; 23 class MCFixup; 24 class MCFragment; 25 class MCObjectWriter; 26 class MCSymbol; 27 class MCSymbolELF; 28 class MCValue; 29 class raw_pwrite_stream; 30 31 struct ELFRelocationEntry { 32 uint64_t Offset; // Where is the relocation. 33 const MCSymbolELF *Symbol; // The symbol to relocate with. 34 unsigned Type; // The type of the relocation. 35 uint64_t Addend; // The addend to use. 36 const MCSymbolELF *OriginalSymbol; // The original value of Symbol if we changed it. 37 uint64_t OriginalAddend; // The original value of addend. 38 ELFRelocationEntryELFRelocationEntry39 ELFRelocationEntry(uint64_t Offset, const MCSymbolELF *Symbol, unsigned Type, 40 uint64_t Addend, const MCSymbolELF *OriginalSymbol, 41 uint64_t OriginalAddend) 42 : Offset(Offset), Symbol(Symbol), Type(Type), Addend(Addend), 43 OriginalSymbol(OriginalSymbol), OriginalAddend(OriginalAddend) {} 44 printELFRelocationEntry45 void print(raw_ostream &Out) const { 46 Out << "Off=" << Offset << ", Sym=" << Symbol << ", Type=" << Type 47 << ", Addend=" << Addend << ", OriginalSymbol=" << OriginalSymbol 48 << ", OriginalAddend=" << OriginalAddend; 49 } dumpELFRelocationEntry50 void dump() const { print(errs()); } 51 }; 52 53 class MCELFObjectTargetWriter { 54 const uint8_t OSABI; 55 const uint16_t EMachine; 56 const unsigned HasRelocationAddend : 1; 57 const unsigned Is64Bit : 1; 58 const unsigned IsN64 : 1; 59 60 protected: 61 62 MCELFObjectTargetWriter(bool Is64Bit_, uint8_t OSABI_, 63 uint16_t EMachine_, bool HasRelocationAddend, 64 bool IsN64=false); 65 66 public: getOSABI(Triple::OSType OSType)67 static uint8_t getOSABI(Triple::OSType OSType) { 68 switch (OSType) { 69 case Triple::CloudABI: 70 return ELF::ELFOSABI_CLOUDABI; 71 case Triple::PS4: 72 case Triple::FreeBSD: 73 return ELF::ELFOSABI_FREEBSD; 74 default: 75 return ELF::ELFOSABI_NONE; 76 } 77 } 78 ~MCELFObjectTargetWriter()79 virtual ~MCELFObjectTargetWriter() {} 80 81 virtual unsigned getRelocType(MCContext &Ctx, const MCValue &Target, 82 const MCFixup &Fixup, bool IsPCRel) const = 0; 83 84 virtual bool needsRelocateWithSymbol(const MCSymbol &Sym, 85 unsigned Type) const; 86 87 virtual void sortRelocs(const MCAssembler &Asm, 88 std::vector<ELFRelocationEntry> &Relocs); 89 90 /// \name Accessors 91 /// @{ getOSABI()92 uint8_t getOSABI() const { return OSABI; } getEMachine()93 uint16_t getEMachine() const { return EMachine; } hasRelocationAddend()94 bool hasRelocationAddend() const { return HasRelocationAddend; } is64Bit()95 bool is64Bit() const { return Is64Bit; } isN64()96 bool isN64() const { return IsN64; } 97 /// @} 98 99 // Instead of changing everyone's API we pack the N64 Type fields 100 // into the existing 32 bit data unsigned. 101 #define R_TYPE_SHIFT 0 102 #define R_TYPE_MASK 0xffffff00 103 #define R_TYPE2_SHIFT 8 104 #define R_TYPE2_MASK 0xffff00ff 105 #define R_TYPE3_SHIFT 16 106 #define R_TYPE3_MASK 0xff00ffff 107 #define R_SSYM_SHIFT 24 108 #define R_SSYM_MASK 0x00ffffff 109 110 // N64 relocation type accessors getRType(uint32_t Type)111 uint8_t getRType(uint32_t Type) const { 112 return (unsigned)((Type >> R_TYPE_SHIFT) & 0xff); 113 } getRType2(uint32_t Type)114 uint8_t getRType2(uint32_t Type) const { 115 return (unsigned)((Type >> R_TYPE2_SHIFT) & 0xff); 116 } getRType3(uint32_t Type)117 uint8_t getRType3(uint32_t Type) const { 118 return (unsigned)((Type >> R_TYPE3_SHIFT) & 0xff); 119 } getRSsym(uint32_t Type)120 uint8_t getRSsym(uint32_t Type) const { 121 return (unsigned)((Type >> R_SSYM_SHIFT) & 0xff); 122 } 123 124 // N64 relocation type setting setRType(unsigned Value,unsigned Type)125 unsigned setRType(unsigned Value, unsigned Type) const { 126 return ((Type & R_TYPE_MASK) | ((Value & 0xff) << R_TYPE_SHIFT)); 127 } setRType2(unsigned Value,unsigned Type)128 unsigned setRType2(unsigned Value, unsigned Type) const { 129 return (Type & R_TYPE2_MASK) | ((Value & 0xff) << R_TYPE2_SHIFT); 130 } setRType3(unsigned Value,unsigned Type)131 unsigned setRType3(unsigned Value, unsigned Type) const { 132 return (Type & R_TYPE3_MASK) | ((Value & 0xff) << R_TYPE3_SHIFT); 133 } setRSsym(unsigned Value,unsigned Type)134 unsigned setRSsym(unsigned Value, unsigned Type) const { 135 return (Type & R_SSYM_MASK) | ((Value & 0xff) << R_SSYM_SHIFT); 136 } 137 }; 138 139 /// \brief Construct a new ELF writer instance. 140 /// 141 /// \param MOTW - The target specific ELF writer subclass. 142 /// \param OS - The stream to write to. 143 /// \returns The constructed object writer. 144 MCObjectWriter *createELFObjectWriter(MCELFObjectTargetWriter *MOTW, 145 raw_pwrite_stream &OS, 146 bool IsLittleEndian); 147 } // End llvm namespace 148 149 #endif 150