1 //===- ELFObjectFile.cpp - ELF object file implementation -----------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Part of the ELFObjectFile class implementation. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/Object/ELFObjectFile.h" 14 #include "llvm/BinaryFormat/ELF.h" 15 #include "llvm/MC/MCInstrAnalysis.h" 16 #include "llvm/MC/SubtargetFeature.h" 17 #include "llvm/MC/TargetRegistry.h" 18 #include "llvm/Object/ELF.h" 19 #include "llvm/Object/ELFTypes.h" 20 #include "llvm/Object/Error.h" 21 #include "llvm/Support/ARMAttributeParser.h" 22 #include "llvm/Support/ARMBuildAttributes.h" 23 #include "llvm/Support/ErrorHandling.h" 24 #include "llvm/Support/MathExtras.h" 25 #include "llvm/Support/RISCVAttributeParser.h" 26 #include "llvm/Support/RISCVAttributes.h" 27 #include "llvm/Support/RISCVISAInfo.h" 28 #include "llvm/TargetParser/Triple.h" 29 #include <algorithm> 30 #include <cstddef> 31 #include <cstdint> 32 #include <memory> 33 #include <optional> 34 #include <string> 35 #include <utility> 36 37 using namespace llvm; 38 using namespace object; 39 40 const EnumEntry<unsigned> llvm::object::ElfSymbolTypes[NumElfSymbolTypes] = { 41 {"None", "NOTYPE", ELF::STT_NOTYPE}, 42 {"Object", "OBJECT", ELF::STT_OBJECT}, 43 {"Function", "FUNC", ELF::STT_FUNC}, 44 {"Section", "SECTION", ELF::STT_SECTION}, 45 {"File", "FILE", ELF::STT_FILE}, 46 {"Common", "COMMON", ELF::STT_COMMON}, 47 {"TLS", "TLS", ELF::STT_TLS}, 48 {"Unknown", "<unknown>: 7", 7}, 49 {"Unknown", "<unknown>: 8", 8}, 50 {"Unknown", "<unknown>: 9", 9}, 51 {"GNU_IFunc", "IFUNC", ELF::STT_GNU_IFUNC}, 52 {"OS Specific", "<OS specific>: 11", 11}, 53 {"OS Specific", "<OS specific>: 12", 12}, 54 {"Proc Specific", "<processor specific>: 13", 13}, 55 {"Proc Specific", "<processor specific>: 14", 14}, 56 {"Proc Specific", "<processor specific>: 15", 15} 57 }; 58 59 ELFObjectFileBase::ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source) 60 : ObjectFile(Type, Source) {} 61 62 template <class ELFT> 63 static Expected<std::unique_ptr<ELFObjectFile<ELFT>>> 64 createPtr(MemoryBufferRef Object, bool InitContent) { 65 auto Ret = ELFObjectFile<ELFT>::create(Object, InitContent); 66 if (Error E = Ret.takeError()) 67 return std::move(E); 68 return std::make_unique<ELFObjectFile<ELFT>>(std::move(*Ret)); 69 } 70 71 Expected<std::unique_ptr<ObjectFile>> 72 ObjectFile::createELFObjectFile(MemoryBufferRef Obj, bool InitContent) { 73 std::pair<unsigned char, unsigned char> Ident = 74 getElfArchType(Obj.getBuffer()); 75 std::size_t MaxAlignment = 76 1ULL << llvm::countr_zero( 77 reinterpret_cast<uintptr_t>(Obj.getBufferStart())); 78 79 if (MaxAlignment < 2) 80 return createError("Insufficient alignment"); 81 82 if (Ident.first == ELF::ELFCLASS32) { 83 if (Ident.second == ELF::ELFDATA2LSB) 84 return createPtr<ELF32LE>(Obj, InitContent); 85 else if (Ident.second == ELF::ELFDATA2MSB) 86 return createPtr<ELF32BE>(Obj, InitContent); 87 else 88 return createError("Invalid ELF data"); 89 } else if (Ident.first == ELF::ELFCLASS64) { 90 if (Ident.second == ELF::ELFDATA2LSB) 91 return createPtr<ELF64LE>(Obj, InitContent); 92 else if (Ident.second == ELF::ELFDATA2MSB) 93 return createPtr<ELF64BE>(Obj, InitContent); 94 else 95 return createError("Invalid ELF data"); 96 } 97 return createError("Invalid ELF class"); 98 } 99 100 SubtargetFeatures ELFObjectFileBase::getMIPSFeatures() const { 101 SubtargetFeatures Features; 102 unsigned PlatformFlags = getPlatformFlags(); 103 104 switch (PlatformFlags & ELF::EF_MIPS_ARCH) { 105 case ELF::EF_MIPS_ARCH_1: 106 break; 107 case ELF::EF_MIPS_ARCH_2: 108 Features.AddFeature("mips2"); 109 break; 110 case ELF::EF_MIPS_ARCH_3: 111 Features.AddFeature("mips3"); 112 break; 113 case ELF::EF_MIPS_ARCH_4: 114 Features.AddFeature("mips4"); 115 break; 116 case ELF::EF_MIPS_ARCH_5: 117 Features.AddFeature("mips5"); 118 break; 119 case ELF::EF_MIPS_ARCH_32: 120 Features.AddFeature("mips32"); 121 break; 122 case ELF::EF_MIPS_ARCH_64: 123 Features.AddFeature("mips64"); 124 break; 125 case ELF::EF_MIPS_ARCH_32R2: 126 Features.AddFeature("mips32r2"); 127 break; 128 case ELF::EF_MIPS_ARCH_64R2: 129 Features.AddFeature("mips64r2"); 130 break; 131 case ELF::EF_MIPS_ARCH_32R6: 132 Features.AddFeature("mips32r6"); 133 break; 134 case ELF::EF_MIPS_ARCH_64R6: 135 Features.AddFeature("mips64r6"); 136 break; 137 default: 138 llvm_unreachable("Unknown EF_MIPS_ARCH value"); 139 } 140 141 switch (PlatformFlags & ELF::EF_MIPS_MACH) { 142 case ELF::EF_MIPS_MACH_NONE: 143 // No feature associated with this value. 144 break; 145 case ELF::EF_MIPS_MACH_OCTEON: 146 Features.AddFeature("cnmips"); 147 break; 148 default: 149 llvm_unreachable("Unknown EF_MIPS_ARCH value"); 150 } 151 152 if (PlatformFlags & ELF::EF_MIPS_ARCH_ASE_M16) 153 Features.AddFeature("mips16"); 154 if (PlatformFlags & ELF::EF_MIPS_MICROMIPS) 155 Features.AddFeature("micromips"); 156 157 return Features; 158 } 159 160 SubtargetFeatures ELFObjectFileBase::getARMFeatures() const { 161 SubtargetFeatures Features; 162 ARMAttributeParser Attributes; 163 if (Error E = getBuildAttributes(Attributes)) { 164 consumeError(std::move(E)); 165 return SubtargetFeatures(); 166 } 167 168 // both ARMv7-M and R have to support thumb hardware div 169 bool isV7 = false; 170 std::optional<unsigned> Attr = 171 Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch); 172 if (Attr) 173 isV7 = *Attr == ARMBuildAttrs::v7; 174 175 Attr = Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile); 176 if (Attr) { 177 switch (*Attr) { 178 case ARMBuildAttrs::ApplicationProfile: 179 Features.AddFeature("aclass"); 180 break; 181 case ARMBuildAttrs::RealTimeProfile: 182 Features.AddFeature("rclass"); 183 if (isV7) 184 Features.AddFeature("hwdiv"); 185 break; 186 case ARMBuildAttrs::MicroControllerProfile: 187 Features.AddFeature("mclass"); 188 if (isV7) 189 Features.AddFeature("hwdiv"); 190 break; 191 } 192 } 193 194 Attr = Attributes.getAttributeValue(ARMBuildAttrs::THUMB_ISA_use); 195 if (Attr) { 196 switch (*Attr) { 197 default: 198 break; 199 case ARMBuildAttrs::Not_Allowed: 200 Features.AddFeature("thumb", false); 201 Features.AddFeature("thumb2", false); 202 break; 203 case ARMBuildAttrs::AllowThumb32: 204 Features.AddFeature("thumb2"); 205 break; 206 } 207 } 208 209 Attr = Attributes.getAttributeValue(ARMBuildAttrs::FP_arch); 210 if (Attr) { 211 switch (*Attr) { 212 default: 213 break; 214 case ARMBuildAttrs::Not_Allowed: 215 Features.AddFeature("vfp2sp", false); 216 Features.AddFeature("vfp3d16sp", false); 217 Features.AddFeature("vfp4d16sp", false); 218 break; 219 case ARMBuildAttrs::AllowFPv2: 220 Features.AddFeature("vfp2"); 221 break; 222 case ARMBuildAttrs::AllowFPv3A: 223 case ARMBuildAttrs::AllowFPv3B: 224 Features.AddFeature("vfp3"); 225 break; 226 case ARMBuildAttrs::AllowFPv4A: 227 case ARMBuildAttrs::AllowFPv4B: 228 Features.AddFeature("vfp4"); 229 break; 230 } 231 } 232 233 Attr = Attributes.getAttributeValue(ARMBuildAttrs::Advanced_SIMD_arch); 234 if (Attr) { 235 switch (*Attr) { 236 default: 237 break; 238 case ARMBuildAttrs::Not_Allowed: 239 Features.AddFeature("neon", false); 240 Features.AddFeature("fp16", false); 241 break; 242 case ARMBuildAttrs::AllowNeon: 243 Features.AddFeature("neon"); 244 break; 245 case ARMBuildAttrs::AllowNeon2: 246 Features.AddFeature("neon"); 247 Features.AddFeature("fp16"); 248 break; 249 } 250 } 251 252 Attr = Attributes.getAttributeValue(ARMBuildAttrs::MVE_arch); 253 if (Attr) { 254 switch (*Attr) { 255 default: 256 break; 257 case ARMBuildAttrs::Not_Allowed: 258 Features.AddFeature("mve", false); 259 Features.AddFeature("mve.fp", false); 260 break; 261 case ARMBuildAttrs::AllowMVEInteger: 262 Features.AddFeature("mve.fp", false); 263 Features.AddFeature("mve"); 264 break; 265 case ARMBuildAttrs::AllowMVEIntegerAndFloat: 266 Features.AddFeature("mve.fp"); 267 break; 268 } 269 } 270 271 Attr = Attributes.getAttributeValue(ARMBuildAttrs::DIV_use); 272 if (Attr) { 273 switch (*Attr) { 274 default: 275 break; 276 case ARMBuildAttrs::DisallowDIV: 277 Features.AddFeature("hwdiv", false); 278 Features.AddFeature("hwdiv-arm", false); 279 break; 280 case ARMBuildAttrs::AllowDIVExt: 281 Features.AddFeature("hwdiv"); 282 Features.AddFeature("hwdiv-arm"); 283 break; 284 } 285 } 286 287 return Features; 288 } 289 290 Expected<SubtargetFeatures> ELFObjectFileBase::getRISCVFeatures() const { 291 SubtargetFeatures Features; 292 unsigned PlatformFlags = getPlatformFlags(); 293 294 if (PlatformFlags & ELF::EF_RISCV_RVC) { 295 Features.AddFeature("c"); 296 } 297 298 RISCVAttributeParser Attributes; 299 if (Error E = getBuildAttributes(Attributes)) { 300 return std::move(E); 301 } 302 303 std::optional<StringRef> Attr = 304 Attributes.getAttributeString(RISCVAttrs::ARCH); 305 if (Attr) { 306 auto ParseResult = RISCVISAInfo::parseNormalizedArchString(*Attr); 307 if (!ParseResult) 308 return ParseResult.takeError(); 309 auto &ISAInfo = *ParseResult; 310 311 if (ISAInfo->getXLen() == 32) 312 Features.AddFeature("64bit", false); 313 else if (ISAInfo->getXLen() == 64) 314 Features.AddFeature("64bit"); 315 else 316 llvm_unreachable("XLEN should be 32 or 64."); 317 318 Features.addFeaturesVector(ISAInfo->toFeatureVector()); 319 } 320 321 return Features; 322 } 323 324 SubtargetFeatures ELFObjectFileBase::getLoongArchFeatures() const { 325 SubtargetFeatures Features; 326 327 switch (getPlatformFlags() & ELF::EF_LOONGARCH_ABI_MODIFIER_MASK) { 328 case ELF::EF_LOONGARCH_ABI_SOFT_FLOAT: 329 break; 330 case ELF::EF_LOONGARCH_ABI_DOUBLE_FLOAT: 331 Features.AddFeature("d"); 332 // D implies F according to LoongArch ISA spec. 333 [[fallthrough]]; 334 case ELF::EF_LOONGARCH_ABI_SINGLE_FLOAT: 335 Features.AddFeature("f"); 336 break; 337 } 338 339 return Features; 340 } 341 342 Expected<SubtargetFeatures> ELFObjectFileBase::getFeatures() const { 343 switch (getEMachine()) { 344 case ELF::EM_MIPS: 345 return getMIPSFeatures(); 346 case ELF::EM_ARM: 347 return getARMFeatures(); 348 case ELF::EM_RISCV: 349 return getRISCVFeatures(); 350 case ELF::EM_LOONGARCH: 351 return getLoongArchFeatures(); 352 default: 353 return SubtargetFeatures(); 354 } 355 } 356 357 std::optional<StringRef> ELFObjectFileBase::tryGetCPUName() const { 358 switch (getEMachine()) { 359 case ELF::EM_AMDGPU: 360 return getAMDGPUCPUName(); 361 case ELF::EM_PPC64: 362 return StringRef("future"); 363 default: 364 return std::nullopt; 365 } 366 } 367 368 StringRef ELFObjectFileBase::getAMDGPUCPUName() const { 369 assert(getEMachine() == ELF::EM_AMDGPU); 370 unsigned CPU = getPlatformFlags() & ELF::EF_AMDGPU_MACH; 371 372 switch (CPU) { 373 // Radeon HD 2000/3000 Series (R600). 374 case ELF::EF_AMDGPU_MACH_R600_R600: 375 return "r600"; 376 case ELF::EF_AMDGPU_MACH_R600_R630: 377 return "r630"; 378 case ELF::EF_AMDGPU_MACH_R600_RS880: 379 return "rs880"; 380 case ELF::EF_AMDGPU_MACH_R600_RV670: 381 return "rv670"; 382 383 // Radeon HD 4000 Series (R700). 384 case ELF::EF_AMDGPU_MACH_R600_RV710: 385 return "rv710"; 386 case ELF::EF_AMDGPU_MACH_R600_RV730: 387 return "rv730"; 388 case ELF::EF_AMDGPU_MACH_R600_RV770: 389 return "rv770"; 390 391 // Radeon HD 5000 Series (Evergreen). 392 case ELF::EF_AMDGPU_MACH_R600_CEDAR: 393 return "cedar"; 394 case ELF::EF_AMDGPU_MACH_R600_CYPRESS: 395 return "cypress"; 396 case ELF::EF_AMDGPU_MACH_R600_JUNIPER: 397 return "juniper"; 398 case ELF::EF_AMDGPU_MACH_R600_REDWOOD: 399 return "redwood"; 400 case ELF::EF_AMDGPU_MACH_R600_SUMO: 401 return "sumo"; 402 403 // Radeon HD 6000 Series (Northern Islands). 404 case ELF::EF_AMDGPU_MACH_R600_BARTS: 405 return "barts"; 406 case ELF::EF_AMDGPU_MACH_R600_CAICOS: 407 return "caicos"; 408 case ELF::EF_AMDGPU_MACH_R600_CAYMAN: 409 return "cayman"; 410 case ELF::EF_AMDGPU_MACH_R600_TURKS: 411 return "turks"; 412 413 // AMDGCN GFX6. 414 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX600: 415 return "gfx600"; 416 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX601: 417 return "gfx601"; 418 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX602: 419 return "gfx602"; 420 421 // AMDGCN GFX7. 422 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX700: 423 return "gfx700"; 424 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX701: 425 return "gfx701"; 426 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX702: 427 return "gfx702"; 428 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX703: 429 return "gfx703"; 430 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX704: 431 return "gfx704"; 432 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX705: 433 return "gfx705"; 434 435 // AMDGCN GFX8. 436 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX801: 437 return "gfx801"; 438 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX802: 439 return "gfx802"; 440 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX803: 441 return "gfx803"; 442 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX805: 443 return "gfx805"; 444 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX810: 445 return "gfx810"; 446 447 // AMDGCN GFX9. 448 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX900: 449 return "gfx900"; 450 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX902: 451 return "gfx902"; 452 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX904: 453 return "gfx904"; 454 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX906: 455 return "gfx906"; 456 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX908: 457 return "gfx908"; 458 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX909: 459 return "gfx909"; 460 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX90A: 461 return "gfx90a"; 462 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX90C: 463 return "gfx90c"; 464 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX940: 465 return "gfx940"; 466 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX941: 467 return "gfx941"; 468 469 // AMDGCN GFX10. 470 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1010: 471 return "gfx1010"; 472 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1011: 473 return "gfx1011"; 474 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1012: 475 return "gfx1012"; 476 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1013: 477 return "gfx1013"; 478 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1030: 479 return "gfx1030"; 480 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1031: 481 return "gfx1031"; 482 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1032: 483 return "gfx1032"; 484 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1033: 485 return "gfx1033"; 486 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1034: 487 return "gfx1034"; 488 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1035: 489 return "gfx1035"; 490 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1036: 491 return "gfx1036"; 492 493 // AMDGCN GFX11. 494 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1100: 495 return "gfx1100"; 496 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1101: 497 return "gfx1101"; 498 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1102: 499 return "gfx1102"; 500 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1103: 501 return "gfx1103"; 502 default: 503 llvm_unreachable("Unknown EF_AMDGPU_MACH value"); 504 } 505 } 506 507 // FIXME Encode from a tablegen description or target parser. 508 void ELFObjectFileBase::setARMSubArch(Triple &TheTriple) const { 509 if (TheTriple.getSubArch() != Triple::NoSubArch) 510 return; 511 512 ARMAttributeParser Attributes; 513 if (Error E = getBuildAttributes(Attributes)) { 514 // TODO Propagate Error. 515 consumeError(std::move(E)); 516 return; 517 } 518 519 std::string Triple; 520 // Default to ARM, but use the triple if it's been set. 521 if (TheTriple.isThumb()) 522 Triple = "thumb"; 523 else 524 Triple = "arm"; 525 526 std::optional<unsigned> Attr = 527 Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch); 528 if (Attr) { 529 switch (*Attr) { 530 case ARMBuildAttrs::v4: 531 Triple += "v4"; 532 break; 533 case ARMBuildAttrs::v4T: 534 Triple += "v4t"; 535 break; 536 case ARMBuildAttrs::v5T: 537 Triple += "v5t"; 538 break; 539 case ARMBuildAttrs::v5TE: 540 Triple += "v5te"; 541 break; 542 case ARMBuildAttrs::v5TEJ: 543 Triple += "v5tej"; 544 break; 545 case ARMBuildAttrs::v6: 546 Triple += "v6"; 547 break; 548 case ARMBuildAttrs::v6KZ: 549 Triple += "v6kz"; 550 break; 551 case ARMBuildAttrs::v6T2: 552 Triple += "v6t2"; 553 break; 554 case ARMBuildAttrs::v6K: 555 Triple += "v6k"; 556 break; 557 case ARMBuildAttrs::v7: { 558 std::optional<unsigned> ArchProfileAttr = 559 Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile); 560 if (ArchProfileAttr && 561 *ArchProfileAttr == ARMBuildAttrs::MicroControllerProfile) 562 Triple += "v7m"; 563 else 564 Triple += "v7"; 565 break; 566 } 567 case ARMBuildAttrs::v6_M: 568 Triple += "v6m"; 569 break; 570 case ARMBuildAttrs::v6S_M: 571 Triple += "v6sm"; 572 break; 573 case ARMBuildAttrs::v7E_M: 574 Triple += "v7em"; 575 break; 576 case ARMBuildAttrs::v8_A: 577 Triple += "v8a"; 578 break; 579 case ARMBuildAttrs::v8_R: 580 Triple += "v8r"; 581 break; 582 case ARMBuildAttrs::v8_M_Base: 583 Triple += "v8m.base"; 584 break; 585 case ARMBuildAttrs::v8_M_Main: 586 Triple += "v8m.main"; 587 break; 588 case ARMBuildAttrs::v8_1_M_Main: 589 Triple += "v8.1m.main"; 590 break; 591 case ARMBuildAttrs::v9_A: 592 Triple += "v9a"; 593 break; 594 } 595 } 596 if (!isLittleEndian()) 597 Triple += "eb"; 598 599 TheTriple.setArchName(Triple); 600 } 601 602 std::vector<std::pair<std::optional<DataRefImpl>, uint64_t>> 603 ELFObjectFileBase::getPltAddresses() const { 604 std::string Err; 605 const auto Triple = makeTriple(); 606 const auto *T = TargetRegistry::lookupTarget(Triple.str(), Err); 607 if (!T) 608 return {}; 609 uint64_t JumpSlotReloc = 0; 610 switch (Triple.getArch()) { 611 case Triple::x86: 612 JumpSlotReloc = ELF::R_386_JUMP_SLOT; 613 break; 614 case Triple::x86_64: 615 JumpSlotReloc = ELF::R_X86_64_JUMP_SLOT; 616 break; 617 case Triple::aarch64: 618 case Triple::aarch64_be: 619 JumpSlotReloc = ELF::R_AARCH64_JUMP_SLOT; 620 break; 621 default: 622 return {}; 623 } 624 std::unique_ptr<const MCInstrInfo> MII(T->createMCInstrInfo()); 625 std::unique_ptr<const MCInstrAnalysis> MIA( 626 T->createMCInstrAnalysis(MII.get())); 627 if (!MIA) 628 return {}; 629 std::optional<SectionRef> Plt, RelaPlt; 630 uint64_t GotBaseVA = 0; 631 for (const SectionRef &Section : sections()) { 632 Expected<StringRef> NameOrErr = Section.getName(); 633 if (!NameOrErr) { 634 consumeError(NameOrErr.takeError()); 635 continue; 636 } 637 StringRef Name = *NameOrErr; 638 639 if (Name == ".plt") 640 Plt = Section; 641 else if (Name == ".rela.plt" || Name == ".rel.plt") 642 RelaPlt = Section; 643 else if (Name == ".got.plt") 644 GotBaseVA = Section.getAddress(); 645 } 646 if (!Plt || !RelaPlt) 647 return {}; 648 Expected<StringRef> PltContents = Plt->getContents(); 649 if (!PltContents) { 650 consumeError(PltContents.takeError()); 651 return {}; 652 } 653 auto PltEntries = MIA->findPltEntries( 654 Plt->getAddress(), arrayRefFromStringRef(*PltContents), Triple); 655 656 // Build a map from GOT entry virtual address to PLT entry virtual address. 657 DenseMap<uint64_t, uint64_t> GotToPlt; 658 for (auto [Plt, GotPltEntry] : PltEntries) { 659 // An x86-32 PIC PLT uses jmp DWORD PTR [ebx-offset]. Add 660 // _GLOBAL_OFFSET_TABLE_ (EBX) to get the .got.plt (or .got) entry address. 661 if (static_cast<int64_t>(GotPltEntry) < 0 && getEMachine() == ELF::EM_386) 662 GotPltEntry = ~GotPltEntry + GotBaseVA; 663 GotToPlt.insert(std::make_pair(GotPltEntry, Plt)); 664 } 665 // Find the relocations in the dynamic relocation table that point to 666 // locations in the GOT for which we know the corresponding PLT entry. 667 std::vector<std::pair<std::optional<DataRefImpl>, uint64_t>> Result; 668 for (const auto &Relocation : RelaPlt->relocations()) { 669 if (Relocation.getType() != JumpSlotReloc) 670 continue; 671 auto PltEntryIter = GotToPlt.find(Relocation.getOffset()); 672 if (PltEntryIter != GotToPlt.end()) { 673 symbol_iterator Sym = Relocation.getSymbol(); 674 if (Sym == symbol_end()) 675 Result.emplace_back(std::nullopt, PltEntryIter->second); 676 else 677 Result.emplace_back(Sym->getRawDataRefImpl(), PltEntryIter->second); 678 } 679 } 680 return Result; 681 } 682 683 template <class ELFT> 684 Expected<std::vector<BBAddrMap>> static readBBAddrMapImpl( 685 const ELFFile<ELFT> &EF, std::optional<unsigned> TextSectionIndex) { 686 using Elf_Shdr = typename ELFT::Shdr; 687 bool IsRelocatable = EF.getHeader().e_type == ELF::ET_REL; 688 std::vector<BBAddrMap> BBAddrMaps; 689 690 const auto &Sections = cantFail(EF.sections()); 691 auto IsMatch = [&](const Elf_Shdr &Sec) -> Expected<bool> { 692 if (Sec.sh_type != ELF::SHT_LLVM_BB_ADDR_MAP && 693 Sec.sh_type != ELF::SHT_LLVM_BB_ADDR_MAP_V0) 694 return false; 695 if (!TextSectionIndex) 696 return true; 697 Expected<const Elf_Shdr *> TextSecOrErr = EF.getSection(Sec.sh_link); 698 if (!TextSecOrErr) 699 return createError("unable to get the linked-to section for " + 700 describe(EF, Sec) + ": " + 701 toString(TextSecOrErr.takeError())); 702 if (*TextSectionIndex != std::distance(Sections.begin(), *TextSecOrErr)) 703 return false; 704 return true; 705 }; 706 707 Expected<MapVector<const Elf_Shdr *, const Elf_Shdr *>> SectionRelocMapOrErr = 708 EF.getSectionAndRelocations(IsMatch); 709 if (!SectionRelocMapOrErr) 710 return SectionRelocMapOrErr.takeError(); 711 712 for (auto const &[Sec, RelocSec] : *SectionRelocMapOrErr) { 713 if (IsRelocatable && !RelocSec) 714 return createError("unable to get relocation section for " + 715 describe(EF, *Sec)); 716 Expected<std::vector<BBAddrMap>> BBAddrMapOrErr = 717 EF.decodeBBAddrMap(*Sec, RelocSec); 718 if (!BBAddrMapOrErr) 719 return createError("unable to read " + describe(EF, *Sec) + ": " + 720 toString(BBAddrMapOrErr.takeError())); 721 std::move(BBAddrMapOrErr->begin(), BBAddrMapOrErr->end(), 722 std::back_inserter(BBAddrMaps)); 723 } 724 return BBAddrMaps; 725 } 726 727 template <class ELFT> 728 static Expected<std::vector<VersionEntry>> 729 readDynsymVersionsImpl(const ELFFile<ELFT> &EF, 730 ELFObjectFileBase::elf_symbol_iterator_range Symbols) { 731 using Elf_Shdr = typename ELFT::Shdr; 732 const Elf_Shdr *VerSec = nullptr; 733 const Elf_Shdr *VerNeedSec = nullptr; 734 const Elf_Shdr *VerDefSec = nullptr; 735 // The user should ensure sections() can't fail here. 736 for (const Elf_Shdr &Sec : cantFail(EF.sections())) { 737 if (Sec.sh_type == ELF::SHT_GNU_versym) 738 VerSec = &Sec; 739 else if (Sec.sh_type == ELF::SHT_GNU_verdef) 740 VerDefSec = &Sec; 741 else if (Sec.sh_type == ELF::SHT_GNU_verneed) 742 VerNeedSec = &Sec; 743 } 744 if (!VerSec) 745 return std::vector<VersionEntry>(); 746 747 Expected<SmallVector<std::optional<VersionEntry>, 0>> MapOrErr = 748 EF.loadVersionMap(VerNeedSec, VerDefSec); 749 if (!MapOrErr) 750 return MapOrErr.takeError(); 751 752 std::vector<VersionEntry> Ret; 753 size_t I = 0; 754 for (const ELFSymbolRef &Sym : Symbols) { 755 ++I; 756 Expected<const typename ELFT::Versym *> VerEntryOrErr = 757 EF.template getEntry<typename ELFT::Versym>(*VerSec, I); 758 if (!VerEntryOrErr) 759 return createError("unable to read an entry with index " + Twine(I) + 760 " from " + describe(EF, *VerSec) + ": " + 761 toString(VerEntryOrErr.takeError())); 762 763 Expected<uint32_t> FlagsOrErr = Sym.getFlags(); 764 if (!FlagsOrErr) 765 return createError("unable to read flags for symbol with index " + 766 Twine(I) + ": " + toString(FlagsOrErr.takeError())); 767 768 bool IsDefault; 769 Expected<StringRef> VerOrErr = EF.getSymbolVersionByIndex( 770 (*VerEntryOrErr)->vs_index, IsDefault, *MapOrErr, 771 (*FlagsOrErr) & SymbolRef::SF_Undefined); 772 if (!VerOrErr) 773 return createError("unable to get a version for entry " + Twine(I) + 774 " of " + describe(EF, *VerSec) + ": " + 775 toString(VerOrErr.takeError())); 776 777 Ret.push_back({(*VerOrErr).str(), IsDefault}); 778 } 779 780 return Ret; 781 } 782 783 Expected<std::vector<VersionEntry>> 784 ELFObjectFileBase::readDynsymVersions() const { 785 elf_symbol_iterator_range Symbols = getDynamicSymbolIterators(); 786 if (const auto *Obj = dyn_cast<ELF32LEObjectFile>(this)) 787 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 788 if (const auto *Obj = dyn_cast<ELF32BEObjectFile>(this)) 789 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 790 if (const auto *Obj = dyn_cast<ELF64LEObjectFile>(this)) 791 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 792 return readDynsymVersionsImpl(cast<ELF64BEObjectFile>(this)->getELFFile(), 793 Symbols); 794 } 795 796 Expected<std::vector<BBAddrMap>> ELFObjectFileBase::readBBAddrMap( 797 std::optional<unsigned> TextSectionIndex) const { 798 if (const auto *Obj = dyn_cast<ELF32LEObjectFile>(this)) 799 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 800 if (const auto *Obj = dyn_cast<ELF64LEObjectFile>(this)) 801 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 802 if (const auto *Obj = dyn_cast<ELF32BEObjectFile>(this)) 803 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 804 return readBBAddrMapImpl(cast<ELF64BEObjectFile>(this)->getELFFile(), 805 TextSectionIndex); 806 } 807