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 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX942: 469 return "gfx942"; 470 471 // AMDGCN GFX10. 472 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1010: 473 return "gfx1010"; 474 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1011: 475 return "gfx1011"; 476 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1012: 477 return "gfx1012"; 478 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1013: 479 return "gfx1013"; 480 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1030: 481 return "gfx1030"; 482 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1031: 483 return "gfx1031"; 484 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1032: 485 return "gfx1032"; 486 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1033: 487 return "gfx1033"; 488 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1034: 489 return "gfx1034"; 490 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1035: 491 return "gfx1035"; 492 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1036: 493 return "gfx1036"; 494 495 // AMDGCN GFX11. 496 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1100: 497 return "gfx1100"; 498 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1101: 499 return "gfx1101"; 500 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1102: 501 return "gfx1102"; 502 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1103: 503 return "gfx1103"; 504 default: 505 llvm_unreachable("Unknown EF_AMDGPU_MACH value"); 506 } 507 } 508 509 // FIXME Encode from a tablegen description or target parser. 510 void ELFObjectFileBase::setARMSubArch(Triple &TheTriple) const { 511 if (TheTriple.getSubArch() != Triple::NoSubArch) 512 return; 513 514 ARMAttributeParser Attributes; 515 if (Error E = getBuildAttributes(Attributes)) { 516 // TODO Propagate Error. 517 consumeError(std::move(E)); 518 return; 519 } 520 521 std::string Triple; 522 // Default to ARM, but use the triple if it's been set. 523 if (TheTriple.isThumb()) 524 Triple = "thumb"; 525 else 526 Triple = "arm"; 527 528 std::optional<unsigned> Attr = 529 Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch); 530 if (Attr) { 531 switch (*Attr) { 532 case ARMBuildAttrs::v4: 533 Triple += "v4"; 534 break; 535 case ARMBuildAttrs::v4T: 536 Triple += "v4t"; 537 break; 538 case ARMBuildAttrs::v5T: 539 Triple += "v5t"; 540 break; 541 case ARMBuildAttrs::v5TE: 542 Triple += "v5te"; 543 break; 544 case ARMBuildAttrs::v5TEJ: 545 Triple += "v5tej"; 546 break; 547 case ARMBuildAttrs::v6: 548 Triple += "v6"; 549 break; 550 case ARMBuildAttrs::v6KZ: 551 Triple += "v6kz"; 552 break; 553 case ARMBuildAttrs::v6T2: 554 Triple += "v6t2"; 555 break; 556 case ARMBuildAttrs::v6K: 557 Triple += "v6k"; 558 break; 559 case ARMBuildAttrs::v7: { 560 std::optional<unsigned> ArchProfileAttr = 561 Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile); 562 if (ArchProfileAttr && 563 *ArchProfileAttr == ARMBuildAttrs::MicroControllerProfile) 564 Triple += "v7m"; 565 else 566 Triple += "v7"; 567 break; 568 } 569 case ARMBuildAttrs::v6_M: 570 Triple += "v6m"; 571 break; 572 case ARMBuildAttrs::v6S_M: 573 Triple += "v6sm"; 574 break; 575 case ARMBuildAttrs::v7E_M: 576 Triple += "v7em"; 577 break; 578 case ARMBuildAttrs::v8_A: 579 Triple += "v8a"; 580 break; 581 case ARMBuildAttrs::v8_R: 582 Triple += "v8r"; 583 break; 584 case ARMBuildAttrs::v8_M_Base: 585 Triple += "v8m.base"; 586 break; 587 case ARMBuildAttrs::v8_M_Main: 588 Triple += "v8m.main"; 589 break; 590 case ARMBuildAttrs::v8_1_M_Main: 591 Triple += "v8.1m.main"; 592 break; 593 case ARMBuildAttrs::v9_A: 594 Triple += "v9a"; 595 break; 596 } 597 } 598 if (!isLittleEndian()) 599 Triple += "eb"; 600 601 TheTriple.setArchName(Triple); 602 } 603 604 std::vector<ELFPltEntry> ELFObjectFileBase::getPltEntries() const { 605 std::string Err; 606 const auto Triple = makeTriple(); 607 const auto *T = TargetRegistry::lookupTarget(Triple.str(), Err); 608 if (!T) 609 return {}; 610 uint32_t JumpSlotReloc = 0, GlobDatReloc = 0; 611 switch (Triple.getArch()) { 612 case Triple::x86: 613 JumpSlotReloc = ELF::R_386_JUMP_SLOT; 614 GlobDatReloc = ELF::R_386_GLOB_DAT; 615 break; 616 case Triple::x86_64: 617 JumpSlotReloc = ELF::R_X86_64_JUMP_SLOT; 618 GlobDatReloc = ELF::R_X86_64_GLOB_DAT; 619 break; 620 case Triple::aarch64: 621 case Triple::aarch64_be: 622 JumpSlotReloc = ELF::R_AARCH64_JUMP_SLOT; 623 break; 624 default: 625 return {}; 626 } 627 std::unique_ptr<const MCInstrInfo> MII(T->createMCInstrInfo()); 628 std::unique_ptr<const MCInstrAnalysis> MIA( 629 T->createMCInstrAnalysis(MII.get())); 630 if (!MIA) 631 return {}; 632 std::vector<std::pair<uint64_t, uint64_t>> PltEntries; 633 std::optional<SectionRef> RelaPlt, RelaDyn; 634 uint64_t GotBaseVA = 0; 635 for (const SectionRef &Section : sections()) { 636 Expected<StringRef> NameOrErr = Section.getName(); 637 if (!NameOrErr) { 638 consumeError(NameOrErr.takeError()); 639 continue; 640 } 641 StringRef Name = *NameOrErr; 642 643 if (Name == ".rela.plt" || Name == ".rel.plt") { 644 RelaPlt = Section; 645 } else if (Name == ".rela.dyn" || Name == ".rel.dyn") { 646 RelaDyn = Section; 647 } else if (Name == ".got.plt") { 648 GotBaseVA = Section.getAddress(); 649 } else if (Name == ".plt" || Name == ".plt.got") { 650 Expected<StringRef> PltContents = Section.getContents(); 651 if (!PltContents) { 652 consumeError(PltContents.takeError()); 653 return {}; 654 } 655 llvm::append_range( 656 PltEntries, 657 MIA->findPltEntries(Section.getAddress(), 658 arrayRefFromStringRef(*PltContents), Triple)); 659 } 660 } 661 662 // Build a map from GOT entry virtual address to PLT entry virtual address. 663 DenseMap<uint64_t, uint64_t> GotToPlt; 664 for (auto [Plt, GotPlt] : PltEntries) { 665 uint64_t GotPltEntry = GotPlt; 666 // An x86-32 PIC PLT uses jmp DWORD PTR [ebx-offset]. Add 667 // _GLOBAL_OFFSET_TABLE_ (EBX) to get the .got.plt (or .got) entry address. 668 // See X86MCTargetDesc.cpp:findPltEntries for the 1 << 32 bit. 669 if (GotPltEntry & (uint64_t(1) << 32) && getEMachine() == ELF::EM_386) 670 GotPltEntry = static_cast<int32_t>(GotPltEntry) + GotBaseVA; 671 GotToPlt.insert(std::make_pair(GotPltEntry, Plt)); 672 } 673 674 // Find the relocations in the dynamic relocation table that point to 675 // locations in the GOT for which we know the corresponding PLT entry. 676 std::vector<ELFPltEntry> Result; 677 auto handleRels = [&](iterator_range<relocation_iterator> Rels, 678 uint32_t RelType, StringRef PltSec) { 679 for (const auto &R : Rels) { 680 if (R.getType() != RelType) 681 continue; 682 auto PltEntryIter = GotToPlt.find(R.getOffset()); 683 if (PltEntryIter != GotToPlt.end()) { 684 symbol_iterator Sym = R.getSymbol(); 685 if (Sym == symbol_end()) 686 Result.push_back( 687 ELFPltEntry{PltSec, std::nullopt, PltEntryIter->second}); 688 else 689 Result.push_back(ELFPltEntry{PltSec, Sym->getRawDataRefImpl(), 690 PltEntryIter->second}); 691 } 692 } 693 }; 694 695 if (RelaPlt) 696 handleRels(RelaPlt->relocations(), JumpSlotReloc, ".plt"); 697 698 // If a symbol needing a PLT entry also needs a GLOB_DAT relocation, GNU ld's 699 // x86 port places the PLT entry in the .plt.got section. 700 if (RelaDyn) 701 handleRels(RelaDyn->relocations(), GlobDatReloc, ".plt.got"); 702 703 return Result; 704 } 705 706 template <class ELFT> 707 Expected<std::vector<BBAddrMap>> static readBBAddrMapImpl( 708 const ELFFile<ELFT> &EF, std::optional<unsigned> TextSectionIndex) { 709 using Elf_Shdr = typename ELFT::Shdr; 710 bool IsRelocatable = EF.getHeader().e_type == ELF::ET_REL; 711 std::vector<BBAddrMap> BBAddrMaps; 712 713 const auto &Sections = cantFail(EF.sections()); 714 auto IsMatch = [&](const Elf_Shdr &Sec) -> Expected<bool> { 715 if (Sec.sh_type != ELF::SHT_LLVM_BB_ADDR_MAP && 716 Sec.sh_type != ELF::SHT_LLVM_BB_ADDR_MAP_V0) 717 return false; 718 if (!TextSectionIndex) 719 return true; 720 Expected<const Elf_Shdr *> TextSecOrErr = EF.getSection(Sec.sh_link); 721 if (!TextSecOrErr) 722 return createError("unable to get the linked-to section for " + 723 describe(EF, Sec) + ": " + 724 toString(TextSecOrErr.takeError())); 725 if (*TextSectionIndex != std::distance(Sections.begin(), *TextSecOrErr)) 726 return false; 727 return true; 728 }; 729 730 Expected<MapVector<const Elf_Shdr *, const Elf_Shdr *>> SectionRelocMapOrErr = 731 EF.getSectionAndRelocations(IsMatch); 732 if (!SectionRelocMapOrErr) 733 return SectionRelocMapOrErr.takeError(); 734 735 for (auto const &[Sec, RelocSec] : *SectionRelocMapOrErr) { 736 if (IsRelocatable && !RelocSec) 737 return createError("unable to get relocation section for " + 738 describe(EF, *Sec)); 739 Expected<std::vector<BBAddrMap>> BBAddrMapOrErr = 740 EF.decodeBBAddrMap(*Sec, RelocSec); 741 if (!BBAddrMapOrErr) 742 return createError("unable to read " + describe(EF, *Sec) + ": " + 743 toString(BBAddrMapOrErr.takeError())); 744 std::move(BBAddrMapOrErr->begin(), BBAddrMapOrErr->end(), 745 std::back_inserter(BBAddrMaps)); 746 } 747 return BBAddrMaps; 748 } 749 750 template <class ELFT> 751 static Expected<std::vector<VersionEntry>> 752 readDynsymVersionsImpl(const ELFFile<ELFT> &EF, 753 ELFObjectFileBase::elf_symbol_iterator_range Symbols) { 754 using Elf_Shdr = typename ELFT::Shdr; 755 const Elf_Shdr *VerSec = nullptr; 756 const Elf_Shdr *VerNeedSec = nullptr; 757 const Elf_Shdr *VerDefSec = nullptr; 758 // The user should ensure sections() can't fail here. 759 for (const Elf_Shdr &Sec : cantFail(EF.sections())) { 760 if (Sec.sh_type == ELF::SHT_GNU_versym) 761 VerSec = &Sec; 762 else if (Sec.sh_type == ELF::SHT_GNU_verdef) 763 VerDefSec = &Sec; 764 else if (Sec.sh_type == ELF::SHT_GNU_verneed) 765 VerNeedSec = &Sec; 766 } 767 if (!VerSec) 768 return std::vector<VersionEntry>(); 769 770 Expected<SmallVector<std::optional<VersionEntry>, 0>> MapOrErr = 771 EF.loadVersionMap(VerNeedSec, VerDefSec); 772 if (!MapOrErr) 773 return MapOrErr.takeError(); 774 775 std::vector<VersionEntry> Ret; 776 size_t I = 0; 777 for (const ELFSymbolRef &Sym : Symbols) { 778 ++I; 779 Expected<const typename ELFT::Versym *> VerEntryOrErr = 780 EF.template getEntry<typename ELFT::Versym>(*VerSec, I); 781 if (!VerEntryOrErr) 782 return createError("unable to read an entry with index " + Twine(I) + 783 " from " + describe(EF, *VerSec) + ": " + 784 toString(VerEntryOrErr.takeError())); 785 786 Expected<uint32_t> FlagsOrErr = Sym.getFlags(); 787 if (!FlagsOrErr) 788 return createError("unable to read flags for symbol with index " + 789 Twine(I) + ": " + toString(FlagsOrErr.takeError())); 790 791 bool IsDefault; 792 Expected<StringRef> VerOrErr = EF.getSymbolVersionByIndex( 793 (*VerEntryOrErr)->vs_index, IsDefault, *MapOrErr, 794 (*FlagsOrErr) & SymbolRef::SF_Undefined); 795 if (!VerOrErr) 796 return createError("unable to get a version for entry " + Twine(I) + 797 " of " + describe(EF, *VerSec) + ": " + 798 toString(VerOrErr.takeError())); 799 800 Ret.push_back({(*VerOrErr).str(), IsDefault}); 801 } 802 803 return Ret; 804 } 805 806 Expected<std::vector<VersionEntry>> 807 ELFObjectFileBase::readDynsymVersions() const { 808 elf_symbol_iterator_range Symbols = getDynamicSymbolIterators(); 809 if (const auto *Obj = dyn_cast<ELF32LEObjectFile>(this)) 810 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 811 if (const auto *Obj = dyn_cast<ELF32BEObjectFile>(this)) 812 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 813 if (const auto *Obj = dyn_cast<ELF64LEObjectFile>(this)) 814 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 815 return readDynsymVersionsImpl(cast<ELF64BEObjectFile>(this)->getELFFile(), 816 Symbols); 817 } 818 819 Expected<std::vector<BBAddrMap>> ELFObjectFileBase::readBBAddrMap( 820 std::optional<unsigned> TextSectionIndex) const { 821 if (const auto *Obj = dyn_cast<ELF32LEObjectFile>(this)) 822 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 823 if (const auto *Obj = dyn_cast<ELF64LEObjectFile>(this)) 824 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 825 if (const auto *Obj = dyn_cast<ELF32BEObjectFile>(this)) 826 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 827 return readBBAddrMapImpl(cast<ELF64BEObjectFile>(this)->getELFFile(), 828 TextSectionIndex); 829 } 830