1 //===-- X86ELFObjectWriter.cpp - X86 ELF Writer ---------------------------===// 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 #include "MCTargetDesc/X86FixupKinds.h" 11 #include "MCTargetDesc/X86MCTargetDesc.h" 12 #include "llvm/MC/MCELFObjectWriter.h" 13 #include "llvm/MC/MCExpr.h" 14 #include "llvm/MC/MCValue.h" 15 #include "llvm/Support/ELF.h" 16 #include "llvm/Support/ErrorHandling.h" 17 18 using namespace llvm; 19 20 namespace { 21 class X86ELFObjectWriter : public MCELFObjectTargetWriter { 22 public: 23 X86ELFObjectWriter(bool IsELF64, uint8_t OSABI, uint16_t EMachine); 24 25 virtual ~X86ELFObjectWriter(); 26 protected: 27 virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, 28 bool IsPCRel, bool IsRelocWithSymbol, 29 int64_t Addend) const; 30 }; 31 } 32 33 X86ELFObjectWriter::X86ELFObjectWriter(bool IsELF64, uint8_t OSABI, 34 uint16_t EMachine) 35 : MCELFObjectTargetWriter(IsELF64, OSABI, EMachine, 36 // Only i386 uses Rel instead of RelA. 37 /*HasRelocationAddend*/ EMachine != ELF::EM_386) {} 38 39 X86ELFObjectWriter::~X86ELFObjectWriter() 40 {} 41 42 unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target, 43 const MCFixup &Fixup, 44 bool IsPCRel, 45 bool IsRelocWithSymbol, 46 int64_t Addend) const { 47 // determine the type of the relocation 48 49 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ? 50 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind(); 51 unsigned Type; 52 if (getEMachine() == ELF::EM_X86_64) { 53 if (IsPCRel) { 54 switch ((unsigned)Fixup.getKind()) { 55 default: llvm_unreachable("invalid fixup kind!"); 56 57 case FK_Data_8: Type = ELF::R_X86_64_PC64; break; 58 case FK_Data_4: Type = ELF::R_X86_64_PC32; break; 59 case FK_Data_2: Type = ELF::R_X86_64_PC16; break; 60 61 case FK_PCRel_8: 62 assert(Modifier == MCSymbolRefExpr::VK_None); 63 Type = ELF::R_X86_64_PC64; 64 break; 65 case X86::reloc_signed_4byte: 66 case X86::reloc_riprel_4byte_movq_load: 67 case X86::reloc_riprel_4byte: 68 case FK_PCRel_4: 69 switch (Modifier) { 70 default: 71 llvm_unreachable("Unimplemented"); 72 case MCSymbolRefExpr::VK_None: 73 Type = ELF::R_X86_64_PC32; 74 break; 75 case MCSymbolRefExpr::VK_PLT: 76 Type = ELF::R_X86_64_PLT32; 77 break; 78 case MCSymbolRefExpr::VK_GOTPCREL: 79 Type = ELF::R_X86_64_GOTPCREL; 80 break; 81 case MCSymbolRefExpr::VK_GOTTPOFF: 82 Type = ELF::R_X86_64_GOTTPOFF; 83 break; 84 case MCSymbolRefExpr::VK_TLSGD: 85 Type = ELF::R_X86_64_TLSGD; 86 break; 87 case MCSymbolRefExpr::VK_TLSLD: 88 Type = ELF::R_X86_64_TLSLD; 89 break; 90 } 91 break; 92 case FK_PCRel_2: 93 assert(Modifier == MCSymbolRefExpr::VK_None); 94 Type = ELF::R_X86_64_PC16; 95 break; 96 case FK_PCRel_1: 97 assert(Modifier == MCSymbolRefExpr::VK_None); 98 Type = ELF::R_X86_64_PC8; 99 break; 100 } 101 } else { 102 switch ((unsigned)Fixup.getKind()) { 103 default: llvm_unreachable("invalid fixup kind!"); 104 case FK_Data_8: Type = ELF::R_X86_64_64; break; 105 case X86::reloc_signed_4byte: 106 switch (Modifier) { 107 default: 108 llvm_unreachable("Unimplemented"); 109 case MCSymbolRefExpr::VK_None: 110 Type = ELF::R_X86_64_32S; 111 break; 112 case MCSymbolRefExpr::VK_GOT: 113 Type = ELF::R_X86_64_GOT32; 114 break; 115 case MCSymbolRefExpr::VK_GOTPCREL: 116 Type = ELF::R_X86_64_GOTPCREL; 117 break; 118 case MCSymbolRefExpr::VK_TPOFF: 119 Type = ELF::R_X86_64_TPOFF32; 120 break; 121 case MCSymbolRefExpr::VK_DTPOFF: 122 Type = ELF::R_X86_64_DTPOFF32; 123 break; 124 } 125 break; 126 case FK_Data_4: 127 Type = ELF::R_X86_64_32; 128 break; 129 case FK_Data_2: Type = ELF::R_X86_64_16; break; 130 case FK_PCRel_1: 131 case FK_Data_1: Type = ELF::R_X86_64_8; break; 132 } 133 } 134 } else if (getEMachine() == ELF::EM_386) { 135 if (IsPCRel) { 136 switch ((unsigned)Fixup.getKind()) { 137 default: llvm_unreachable("invalid fixup kind!"); 138 139 case X86::reloc_global_offset_table: 140 Type = ELF::R_386_GOTPC; 141 break; 142 143 case X86::reloc_signed_4byte: 144 case FK_PCRel_4: 145 case FK_Data_4: 146 switch (Modifier) { 147 default: 148 llvm_unreachable("Unimplemented"); 149 case MCSymbolRefExpr::VK_None: 150 Type = ELF::R_386_PC32; 151 break; 152 case MCSymbolRefExpr::VK_PLT: 153 Type = ELF::R_386_PLT32; 154 break; 155 } 156 break; 157 } 158 } else { 159 switch ((unsigned)Fixup.getKind()) { 160 default: llvm_unreachable("invalid fixup kind!"); 161 162 case X86::reloc_global_offset_table: 163 Type = ELF::R_386_GOTPC; 164 break; 165 166 // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode 167 // instead? 168 case X86::reloc_signed_4byte: 169 case FK_PCRel_4: 170 case FK_Data_4: 171 switch (Modifier) { 172 default: 173 llvm_unreachable("Unimplemented"); 174 case MCSymbolRefExpr::VK_None: 175 Type = ELF::R_386_32; 176 break; 177 case MCSymbolRefExpr::VK_GOT: 178 Type = ELF::R_386_GOT32; 179 break; 180 case MCSymbolRefExpr::VK_GOTOFF: 181 Type = ELF::R_386_GOTOFF; 182 break; 183 case MCSymbolRefExpr::VK_TLSGD: 184 Type = ELF::R_386_TLS_GD; 185 break; 186 case MCSymbolRefExpr::VK_TPOFF: 187 Type = ELF::R_386_TLS_LE_32; 188 break; 189 case MCSymbolRefExpr::VK_INDNTPOFF: 190 Type = ELF::R_386_TLS_IE; 191 break; 192 case MCSymbolRefExpr::VK_NTPOFF: 193 Type = ELF::R_386_TLS_LE; 194 break; 195 case MCSymbolRefExpr::VK_GOTNTPOFF: 196 Type = ELF::R_386_TLS_GOTIE; 197 break; 198 case MCSymbolRefExpr::VK_TLSLDM: 199 Type = ELF::R_386_TLS_LDM; 200 break; 201 case MCSymbolRefExpr::VK_DTPOFF: 202 Type = ELF::R_386_TLS_LDO_32; 203 break; 204 case MCSymbolRefExpr::VK_GOTTPOFF: 205 Type = ELF::R_386_TLS_IE_32; 206 break; 207 } 208 break; 209 case FK_Data_2: Type = ELF::R_386_16; break; 210 case FK_PCRel_1: 211 case FK_Data_1: Type = ELF::R_386_8; break; 212 } 213 } 214 } else 215 llvm_unreachable("Unsupported ELF machine type."); 216 217 return Type; 218 } 219 220 MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS, 221 bool IsELF64, 222 uint8_t OSABI, 223 uint16_t EMachine) { 224 MCELFObjectTargetWriter *MOTW = 225 new X86ELFObjectWriter(IsELF64, OSABI, EMachine); 226 return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/true); 227 } 228
