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: 105 switch (Modifier) { 106 default: 107 llvm_unreachable("Unimplemented"); 108 case MCSymbolRefExpr::VK_None: 109 Type = ELF::R_X86_64_64; 110 break; 111 case MCSymbolRefExpr::VK_DTPOFF: 112 Type = ELF::R_X86_64_DTPOFF64; 113 break; 114 } 115 break; 116 case X86::reloc_signed_4byte: 117 switch (Modifier) { 118 default: 119 llvm_unreachable("Unimplemented"); 120 case MCSymbolRefExpr::VK_None: 121 Type = ELF::R_X86_64_32S; 122 break; 123 case MCSymbolRefExpr::VK_GOT: 124 Type = ELF::R_X86_64_GOT32; 125 break; 126 case MCSymbolRefExpr::VK_GOTPCREL: 127 Type = ELF::R_X86_64_GOTPCREL; 128 break; 129 case MCSymbolRefExpr::VK_TPOFF: 130 Type = ELF::R_X86_64_TPOFF32; 131 break; 132 case MCSymbolRefExpr::VK_DTPOFF: 133 Type = ELF::R_X86_64_DTPOFF32; 134 break; 135 } 136 break; 137 case FK_Data_4: 138 Type = ELF::R_X86_64_32; 139 break; 140 case FK_Data_2: Type = ELF::R_X86_64_16; break; 141 case FK_PCRel_1: 142 case FK_Data_1: Type = ELF::R_X86_64_8; break; 143 } 144 } 145 } else if (getEMachine() == ELF::EM_386) { 146 if (IsPCRel) { 147 switch ((unsigned)Fixup.getKind()) { 148 default: llvm_unreachable("invalid fixup kind!"); 149 150 case X86::reloc_global_offset_table: 151 Type = ELF::R_386_GOTPC; 152 break; 153 154 case X86::reloc_signed_4byte: 155 case FK_PCRel_4: 156 case FK_Data_4: 157 switch (Modifier) { 158 default: 159 llvm_unreachable("Unimplemented"); 160 case MCSymbolRefExpr::VK_None: 161 Type = ELF::R_386_PC32; 162 break; 163 case MCSymbolRefExpr::VK_PLT: 164 Type = ELF::R_386_PLT32; 165 break; 166 } 167 break; 168 } 169 } else { 170 switch ((unsigned)Fixup.getKind()) { 171 default: llvm_unreachable("invalid fixup kind!"); 172 173 case X86::reloc_global_offset_table: 174 Type = ELF::R_386_GOTPC; 175 break; 176 177 // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode 178 // instead? 179 case X86::reloc_signed_4byte: 180 case FK_PCRel_4: 181 case FK_Data_4: 182 switch (Modifier) { 183 default: 184 llvm_unreachable("Unimplemented"); 185 case MCSymbolRefExpr::VK_None: 186 Type = ELF::R_386_32; 187 break; 188 case MCSymbolRefExpr::VK_GOT: 189 Type = ELF::R_386_GOT32; 190 break; 191 case MCSymbolRefExpr::VK_GOTOFF: 192 Type = ELF::R_386_GOTOFF; 193 break; 194 case MCSymbolRefExpr::VK_TLSGD: 195 Type = ELF::R_386_TLS_GD; 196 break; 197 case MCSymbolRefExpr::VK_TPOFF: 198 Type = ELF::R_386_TLS_LE_32; 199 break; 200 case MCSymbolRefExpr::VK_INDNTPOFF: 201 Type = ELF::R_386_TLS_IE; 202 break; 203 case MCSymbolRefExpr::VK_NTPOFF: 204 Type = ELF::R_386_TLS_LE; 205 break; 206 case MCSymbolRefExpr::VK_GOTNTPOFF: 207 Type = ELF::R_386_TLS_GOTIE; 208 break; 209 case MCSymbolRefExpr::VK_TLSLDM: 210 Type = ELF::R_386_TLS_LDM; 211 break; 212 case MCSymbolRefExpr::VK_DTPOFF: 213 Type = ELF::R_386_TLS_LDO_32; 214 break; 215 case MCSymbolRefExpr::VK_GOTTPOFF: 216 Type = ELF::R_386_TLS_IE_32; 217 break; 218 } 219 break; 220 case FK_Data_2: Type = ELF::R_386_16; break; 221 case FK_PCRel_1: 222 case FK_Data_1: Type = ELF::R_386_8; break; 223 } 224 } 225 } else 226 llvm_unreachable("Unsupported ELF machine type."); 227 228 return Type; 229 } 230 231 MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS, 232 bool IsELF64, 233 uint8_t OSABI, 234 uint16_t EMachine) { 235 MCELFObjectTargetWriter *MOTW = 236 new X86ELFObjectWriter(IsELF64, OSABI, EMachine); 237 return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/true); 238 } 239
