1 //===- ELF.cpp - ELF object file implementation ---------------------------===// 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 "llvm/Object/ELF.h" 11 #include "llvm/BinaryFormat/ELF.h" 12 #include "llvm/Support/LEB128.h" 13 14 using namespace llvm; 15 using namespace object; 16 17 #define STRINGIFY_ENUM_CASE(ns, name) \ 18 case ns::name: \ 19 return #name; 20 21 #define ELF_RELOC(name, value) STRINGIFY_ENUM_CASE(ELF, name) 22 23 StringRef llvm::object::getELFRelocationTypeName(uint32_t Machine, 24 uint32_t Type) { 25 switch (Machine) { 26 case ELF::EM_X86_64: 27 switch (Type) { 28 #include "llvm/BinaryFormat/ELFRelocs/x86_64.def" 29 default: 30 break; 31 } 32 break; 33 case ELF::EM_386: 34 case ELF::EM_IAMCU: 35 switch (Type) { 36 #include "llvm/BinaryFormat/ELFRelocs/i386.def" 37 default: 38 break; 39 } 40 break; 41 case ELF::EM_MIPS: 42 switch (Type) { 43 #include "llvm/BinaryFormat/ELFRelocs/Mips.def" 44 default: 45 break; 46 } 47 break; 48 case ELF::EM_AARCH64: 49 switch (Type) { 50 #include "llvm/BinaryFormat/ELFRelocs/AArch64.def" 51 default: 52 break; 53 } 54 break; 55 case ELF::EM_ARM: 56 switch (Type) { 57 #include "llvm/BinaryFormat/ELFRelocs/ARM.def" 58 default: 59 break; 60 } 61 break; 62 case ELF::EM_ARC_COMPACT: 63 case ELF::EM_ARC_COMPACT2: 64 switch (Type) { 65 #include "llvm/BinaryFormat/ELFRelocs/ARC.def" 66 default: 67 break; 68 } 69 break; 70 case ELF::EM_AVR: 71 switch (Type) { 72 #include "llvm/BinaryFormat/ELFRelocs/AVR.def" 73 default: 74 break; 75 } 76 break; 77 case ELF::EM_HEXAGON: 78 switch (Type) { 79 #include "llvm/BinaryFormat/ELFRelocs/Hexagon.def" 80 default: 81 break; 82 } 83 break; 84 case ELF::EM_LANAI: 85 switch (Type) { 86 #include "llvm/BinaryFormat/ELFRelocs/Lanai.def" 87 default: 88 break; 89 } 90 break; 91 case ELF::EM_PPC: 92 switch (Type) { 93 #include "llvm/BinaryFormat/ELFRelocs/PowerPC.def" 94 default: 95 break; 96 } 97 break; 98 case ELF::EM_PPC64: 99 switch (Type) { 100 #include "llvm/BinaryFormat/ELFRelocs/PowerPC64.def" 101 default: 102 break; 103 } 104 break; 105 case ELF::EM_RISCV: 106 switch (Type) { 107 #include "llvm/BinaryFormat/ELFRelocs/RISCV.def" 108 default: 109 break; 110 } 111 break; 112 case ELF::EM_S390: 113 switch (Type) { 114 #include "llvm/BinaryFormat/ELFRelocs/SystemZ.def" 115 default: 116 break; 117 } 118 break; 119 case ELF::EM_SPARC: 120 case ELF::EM_SPARC32PLUS: 121 case ELF::EM_SPARCV9: 122 switch (Type) { 123 #include "llvm/BinaryFormat/ELFRelocs/Sparc.def" 124 default: 125 break; 126 } 127 break; 128 case ELF::EM_WEBASSEMBLY: 129 switch (Type) { 130 #include "llvm/BinaryFormat/ELFRelocs/WebAssembly.def" 131 default: 132 break; 133 } 134 break; 135 case ELF::EM_AMDGPU: 136 switch (Type) { 137 #include "llvm/BinaryFormat/ELFRelocs/AMDGPU.def" 138 default: 139 break; 140 } 141 case ELF::EM_BPF: 142 switch (Type) { 143 #include "llvm/BinaryFormat/ELFRelocs/BPF.def" 144 default: 145 break; 146 } 147 break; 148 default: 149 break; 150 } 151 return "Unknown"; 152 } 153 154 #undef ELF_RELOC 155 156 StringRef llvm::object::getELFSectionTypeName(uint32_t Machine, unsigned Type) { 157 switch (Machine) { 158 case ELF::EM_ARM: 159 switch (Type) { 160 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_EXIDX); 161 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_PREEMPTMAP); 162 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_ATTRIBUTES); 163 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_DEBUGOVERLAY); 164 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_OVERLAYSECTION); 165 } 166 break; 167 case ELF::EM_HEXAGON: 168 switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_HEX_ORDERED); } 169 break; 170 case ELF::EM_X86_64: 171 switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_X86_64_UNWIND); } 172 break; 173 case ELF::EM_MIPS: 174 case ELF::EM_MIPS_RS3_LE: 175 switch (Type) { 176 STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_REGINFO); 177 STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_OPTIONS); 178 STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_ABIFLAGS); 179 STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_DWARF); 180 } 181 break; 182 default: 183 break; 184 } 185 186 switch (Type) { 187 STRINGIFY_ENUM_CASE(ELF, SHT_NULL); 188 STRINGIFY_ENUM_CASE(ELF, SHT_PROGBITS); 189 STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB); 190 STRINGIFY_ENUM_CASE(ELF, SHT_STRTAB); 191 STRINGIFY_ENUM_CASE(ELF, SHT_RELA); 192 STRINGIFY_ENUM_CASE(ELF, SHT_HASH); 193 STRINGIFY_ENUM_CASE(ELF, SHT_DYNAMIC); 194 STRINGIFY_ENUM_CASE(ELF, SHT_NOTE); 195 STRINGIFY_ENUM_CASE(ELF, SHT_NOBITS); 196 STRINGIFY_ENUM_CASE(ELF, SHT_REL); 197 STRINGIFY_ENUM_CASE(ELF, SHT_SHLIB); 198 STRINGIFY_ENUM_CASE(ELF, SHT_DYNSYM); 199 STRINGIFY_ENUM_CASE(ELF, SHT_INIT_ARRAY); 200 STRINGIFY_ENUM_CASE(ELF, SHT_FINI_ARRAY); 201 STRINGIFY_ENUM_CASE(ELF, SHT_PREINIT_ARRAY); 202 STRINGIFY_ENUM_CASE(ELF, SHT_GROUP); 203 STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB_SHNDX); 204 STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ODRTAB); 205 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_ATTRIBUTES); 206 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_HASH); 207 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verdef); 208 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verneed); 209 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_versym); 210 default: 211 return "Unknown"; 212 } 213 } 214 215 template <class ELFT> 216 Expected<std::vector<typename ELFT::Rela>> 217 ELFFile<ELFT>::android_relas(const Elf_Shdr *Sec) const { 218 // This function reads relocations in Android's packed relocation format, 219 // which is based on SLEB128 and delta encoding. 220 Expected<ArrayRef<uint8_t>> ContentsOrErr = getSectionContents(Sec); 221 if (!ContentsOrErr) 222 return ContentsOrErr.takeError(); 223 const uint8_t *Cur = ContentsOrErr->begin(); 224 const uint8_t *End = ContentsOrErr->end(); 225 if (ContentsOrErr->size() < 4 || Cur[0] != 'A' || Cur[1] != 'P' || 226 Cur[2] != 'S' || Cur[3] != '2') 227 return createError("invalid packed relocation header"); 228 Cur += 4; 229 230 const char *ErrStr = nullptr; 231 auto ReadSLEB = [&]() -> int64_t { 232 if (ErrStr) 233 return 0; 234 unsigned Len; 235 int64_t Result = decodeSLEB128(Cur, &Len, End, &ErrStr); 236 Cur += Len; 237 return Result; 238 }; 239 240 uint64_t NumRelocs = ReadSLEB(); 241 uint64_t Offset = ReadSLEB(); 242 uint64_t Addend = 0; 243 244 if (ErrStr) 245 return createError(ErrStr); 246 247 std::vector<Elf_Rela> Relocs; 248 Relocs.reserve(NumRelocs); 249 while (NumRelocs) { 250 uint64_t NumRelocsInGroup = ReadSLEB(); 251 if (NumRelocsInGroup > NumRelocs) 252 return createError("relocation group unexpectedly large"); 253 NumRelocs -= NumRelocsInGroup; 254 255 uint64_t GroupFlags = ReadSLEB(); 256 bool GroupedByInfo = GroupFlags & ELF::RELOCATION_GROUPED_BY_INFO_FLAG; 257 bool GroupedByOffsetDelta = GroupFlags & ELF::RELOCATION_GROUPED_BY_OFFSET_DELTA_FLAG; 258 bool GroupedByAddend = GroupFlags & ELF::RELOCATION_GROUPED_BY_ADDEND_FLAG; 259 bool GroupHasAddend = GroupFlags & ELF::RELOCATION_GROUP_HAS_ADDEND_FLAG; 260 261 uint64_t GroupOffsetDelta; 262 if (GroupedByOffsetDelta) 263 GroupOffsetDelta = ReadSLEB(); 264 265 uint64_t GroupRInfo; 266 if (GroupedByInfo) 267 GroupRInfo = ReadSLEB(); 268 269 if (GroupedByAddend && GroupHasAddend) 270 Addend += ReadSLEB(); 271 272 for (uint64_t I = 0; I != NumRelocsInGroup; ++I) { 273 Elf_Rela R; 274 Offset += GroupedByOffsetDelta ? GroupOffsetDelta : ReadSLEB(); 275 R.r_offset = Offset; 276 R.r_info = GroupedByInfo ? GroupRInfo : ReadSLEB(); 277 278 if (GroupHasAddend) { 279 if (!GroupedByAddend) 280 Addend += ReadSLEB(); 281 R.r_addend = Addend; 282 } else { 283 R.r_addend = 0; 284 } 285 286 Relocs.push_back(R); 287 288 if (ErrStr) 289 return createError(ErrStr); 290 } 291 292 if (ErrStr) 293 return createError(ErrStr); 294 } 295 296 return Relocs; 297 } 298 299 template class llvm::object::ELFFile<ELF32LE>; 300 template class llvm::object::ELFFile<ELF32BE>; 301 template class llvm::object::ELFFile<ELF64LE>; 302 template class llvm::object::ELFFile<ELF64BE>; 303