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/ADT/Triple.h" 15 #include "llvm/BinaryFormat/ELF.h" 16 #include "llvm/MC/MCInstrAnalysis.h" 17 #include "llvm/MC/SubtargetFeature.h" 18 #include "llvm/MC/TargetRegistry.h" 19 #include "llvm/Object/ELF.h" 20 #include "llvm/Object/ELFTypes.h" 21 #include "llvm/Object/Error.h" 22 #include "llvm/Support/ARMAttributeParser.h" 23 #include "llvm/Support/ARMBuildAttributes.h" 24 #include "llvm/Support/ErrorHandling.h" 25 #include "llvm/Support/MathExtras.h" 26 #include "llvm/Support/RISCVAttributeParser.h" 27 #include "llvm/Support/RISCVAttributes.h" 28 #include <algorithm> 29 #include <cstddef> 30 #include <cstdint> 31 #include <memory> 32 #include <optional> 33 #include <string> 34 #include <utility> 35 36 using namespace llvm; 37 using namespace object; 38 39 const EnumEntry<unsigned> llvm::object::ElfSymbolTypes[NumElfSymbolTypes] = { 40 {"None", "NOTYPE", ELF::STT_NOTYPE}, 41 {"Object", "OBJECT", ELF::STT_OBJECT}, 42 {"Function", "FUNC", ELF::STT_FUNC}, 43 {"Section", "SECTION", ELF::STT_SECTION}, 44 {"File", "FILE", ELF::STT_FILE}, 45 {"Common", "COMMON", ELF::STT_COMMON}, 46 {"TLS", "TLS", ELF::STT_TLS}, 47 {"Unknown", "<unknown>: 7", 7}, 48 {"Unknown", "<unknown>: 8", 8}, 49 {"Unknown", "<unknown>: 9", 9}, 50 {"GNU_IFunc", "IFUNC", ELF::STT_GNU_IFUNC}, 51 {"OS Specific", "<OS specific>: 11", 11}, 52 {"OS Specific", "<OS specific>: 12", 12}, 53 {"Proc Specific", "<processor specific>: 13", 13}, 54 {"Proc Specific", "<processor specific>: 14", 14}, 55 {"Proc Specific", "<processor specific>: 15", 15} 56 }; 57 58 ELFObjectFileBase::ELFObjectFileBase(unsigned int Type, MemoryBufferRef Source) 59 : ObjectFile(Type, Source) {} 60 61 template <class ELFT> 62 static Expected<std::unique_ptr<ELFObjectFile<ELFT>>> 63 createPtr(MemoryBufferRef Object, bool InitContent) { 64 auto Ret = ELFObjectFile<ELFT>::create(Object, InitContent); 65 if (Error E = Ret.takeError()) 66 return std::move(E); 67 return std::make_unique<ELFObjectFile<ELFT>>(std::move(*Ret)); 68 } 69 70 Expected<std::unique_ptr<ObjectFile>> 71 ObjectFile::createELFObjectFile(MemoryBufferRef Obj, bool InitContent) { 72 std::pair<unsigned char, unsigned char> Ident = 73 getElfArchType(Obj.getBuffer()); 74 std::size_t MaxAlignment = 75 1ULL << countTrailingZeros( 76 reinterpret_cast<uintptr_t>(Obj.getBufferStart())); 77 78 if (MaxAlignment < 2) 79 return createError("Insufficient alignment"); 80 81 if (Ident.first == ELF::ELFCLASS32) { 82 if (Ident.second == ELF::ELFDATA2LSB) 83 return createPtr<ELF32LE>(Obj, InitContent); 84 else if (Ident.second == ELF::ELFDATA2MSB) 85 return createPtr<ELF32BE>(Obj, InitContent); 86 else 87 return createError("Invalid ELF data"); 88 } else if (Ident.first == ELF::ELFCLASS64) { 89 if (Ident.second == ELF::ELFDATA2LSB) 90 return createPtr<ELF64LE>(Obj, InitContent); 91 else if (Ident.second == ELF::ELFDATA2MSB) 92 return createPtr<ELF64BE>(Obj, InitContent); 93 else 94 return createError("Invalid ELF data"); 95 } 96 return createError("Invalid ELF class"); 97 } 98 99 SubtargetFeatures ELFObjectFileBase::getMIPSFeatures() const { 100 SubtargetFeatures Features; 101 unsigned PlatformFlags = getPlatformFlags(); 102 103 switch (PlatformFlags & ELF::EF_MIPS_ARCH) { 104 case ELF::EF_MIPS_ARCH_1: 105 break; 106 case ELF::EF_MIPS_ARCH_2: 107 Features.AddFeature("mips2"); 108 break; 109 case ELF::EF_MIPS_ARCH_3: 110 Features.AddFeature("mips3"); 111 break; 112 case ELF::EF_MIPS_ARCH_4: 113 Features.AddFeature("mips4"); 114 break; 115 case ELF::EF_MIPS_ARCH_5: 116 Features.AddFeature("mips5"); 117 break; 118 case ELF::EF_MIPS_ARCH_32: 119 Features.AddFeature("mips32"); 120 break; 121 case ELF::EF_MIPS_ARCH_64: 122 Features.AddFeature("mips64"); 123 break; 124 case ELF::EF_MIPS_ARCH_32R2: 125 Features.AddFeature("mips32r2"); 126 break; 127 case ELF::EF_MIPS_ARCH_64R2: 128 Features.AddFeature("mips64r2"); 129 break; 130 case ELF::EF_MIPS_ARCH_32R6: 131 Features.AddFeature("mips32r6"); 132 break; 133 case ELF::EF_MIPS_ARCH_64R6: 134 Features.AddFeature("mips64r6"); 135 break; 136 default: 137 llvm_unreachable("Unknown EF_MIPS_ARCH value"); 138 } 139 140 switch (PlatformFlags & ELF::EF_MIPS_MACH) { 141 case ELF::EF_MIPS_MACH_NONE: 142 // No feature associated with this value. 143 break; 144 case ELF::EF_MIPS_MACH_OCTEON: 145 Features.AddFeature("cnmips"); 146 break; 147 default: 148 llvm_unreachable("Unknown EF_MIPS_ARCH value"); 149 } 150 151 if (PlatformFlags & ELF::EF_MIPS_ARCH_ASE_M16) 152 Features.AddFeature("mips16"); 153 if (PlatformFlags & ELF::EF_MIPS_MICROMIPS) 154 Features.AddFeature("micromips"); 155 156 return Features; 157 } 158 159 SubtargetFeatures ELFObjectFileBase::getARMFeatures() const { 160 SubtargetFeatures Features; 161 ARMAttributeParser Attributes; 162 if (Error E = getBuildAttributes(Attributes)) { 163 consumeError(std::move(E)); 164 return SubtargetFeatures(); 165 } 166 167 // both ARMv7-M and R have to support thumb hardware div 168 bool isV7 = false; 169 Optional<unsigned> Attr = 170 Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch); 171 if (Attr) 172 isV7 = Attr.value() == ARMBuildAttrs::v7; 173 174 Attr = Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile); 175 if (Attr) { 176 switch (Attr.value()) { 177 case ARMBuildAttrs::ApplicationProfile: 178 Features.AddFeature("aclass"); 179 break; 180 case ARMBuildAttrs::RealTimeProfile: 181 Features.AddFeature("rclass"); 182 if (isV7) 183 Features.AddFeature("hwdiv"); 184 break; 185 case ARMBuildAttrs::MicroControllerProfile: 186 Features.AddFeature("mclass"); 187 if (isV7) 188 Features.AddFeature("hwdiv"); 189 break; 190 } 191 } 192 193 Attr = Attributes.getAttributeValue(ARMBuildAttrs::THUMB_ISA_use); 194 if (Attr) { 195 switch (Attr.value()) { 196 default: 197 break; 198 case ARMBuildAttrs::Not_Allowed: 199 Features.AddFeature("thumb", false); 200 Features.AddFeature("thumb2", false); 201 break; 202 case ARMBuildAttrs::AllowThumb32: 203 Features.AddFeature("thumb2"); 204 break; 205 } 206 } 207 208 Attr = Attributes.getAttributeValue(ARMBuildAttrs::FP_arch); 209 if (Attr) { 210 switch (Attr.value()) { 211 default: 212 break; 213 case ARMBuildAttrs::Not_Allowed: 214 Features.AddFeature("vfp2sp", false); 215 Features.AddFeature("vfp3d16sp", false); 216 Features.AddFeature("vfp4d16sp", false); 217 break; 218 case ARMBuildAttrs::AllowFPv2: 219 Features.AddFeature("vfp2"); 220 break; 221 case ARMBuildAttrs::AllowFPv3A: 222 case ARMBuildAttrs::AllowFPv3B: 223 Features.AddFeature("vfp3"); 224 break; 225 case ARMBuildAttrs::AllowFPv4A: 226 case ARMBuildAttrs::AllowFPv4B: 227 Features.AddFeature("vfp4"); 228 break; 229 } 230 } 231 232 Attr = Attributes.getAttributeValue(ARMBuildAttrs::Advanced_SIMD_arch); 233 if (Attr) { 234 switch (Attr.value()) { 235 default: 236 break; 237 case ARMBuildAttrs::Not_Allowed: 238 Features.AddFeature("neon", false); 239 Features.AddFeature("fp16", false); 240 break; 241 case ARMBuildAttrs::AllowNeon: 242 Features.AddFeature("neon"); 243 break; 244 case ARMBuildAttrs::AllowNeon2: 245 Features.AddFeature("neon"); 246 Features.AddFeature("fp16"); 247 break; 248 } 249 } 250 251 Attr = Attributes.getAttributeValue(ARMBuildAttrs::MVE_arch); 252 if (Attr) { 253 switch (Attr.value()) { 254 default: 255 break; 256 case ARMBuildAttrs::Not_Allowed: 257 Features.AddFeature("mve", false); 258 Features.AddFeature("mve.fp", false); 259 break; 260 case ARMBuildAttrs::AllowMVEInteger: 261 Features.AddFeature("mve.fp", false); 262 Features.AddFeature("mve"); 263 break; 264 case ARMBuildAttrs::AllowMVEIntegerAndFloat: 265 Features.AddFeature("mve.fp"); 266 break; 267 } 268 } 269 270 Attr = Attributes.getAttributeValue(ARMBuildAttrs::DIV_use); 271 if (Attr) { 272 switch (Attr.value()) { 273 default: 274 break; 275 case ARMBuildAttrs::DisallowDIV: 276 Features.AddFeature("hwdiv", false); 277 Features.AddFeature("hwdiv-arm", false); 278 break; 279 case ARMBuildAttrs::AllowDIVExt: 280 Features.AddFeature("hwdiv"); 281 Features.AddFeature("hwdiv-arm"); 282 break; 283 } 284 } 285 286 return Features; 287 } 288 289 SubtargetFeatures ELFObjectFileBase::getRISCVFeatures() const { 290 SubtargetFeatures Features; 291 unsigned PlatformFlags = getPlatformFlags(); 292 293 if (PlatformFlags & ELF::EF_RISCV_RVC) { 294 Features.AddFeature("c"); 295 } 296 297 // Add features according to the ELF attribute section. 298 // If there are any unrecognized features, ignore them. 299 RISCVAttributeParser Attributes; 300 if (Error E = getBuildAttributes(Attributes)) { 301 // TODO Propagate Error. 302 consumeError(std::move(E)); 303 return Features; // Keep "c" feature if there is one in PlatformFlags. 304 } 305 306 Optional<StringRef> Attr = Attributes.getAttributeString(RISCVAttrs::ARCH); 307 if (Attr) { 308 // The Arch pattern is [rv32|rv64][i|e]version(_[m|a|f|d|c]version)* 309 // Version string pattern is (major)p(minor). Major and minor are optional. 310 // For example, a version number could be 2p0, 2, or p92. 311 StringRef Arch = *Attr; 312 if (Arch.consume_front("rv32")) 313 Features.AddFeature("64bit", false); 314 else if (Arch.consume_front("rv64")) 315 Features.AddFeature("64bit"); 316 317 while (!Arch.empty()) { 318 switch (Arch[0]) { 319 default: 320 break; // Ignore unexpected features. 321 case 'i': 322 Features.AddFeature("e", false); 323 break; 324 case 'd': 325 Features.AddFeature("f"); // D-ext will imply F-ext. 326 [[fallthrough]]; 327 case 'e': 328 case 'm': 329 case 'a': 330 case 'f': 331 case 'c': 332 Features.AddFeature(Arch.take_front()); 333 break; 334 } 335 336 // FIXME: Handle version numbers. 337 Arch = Arch.drop_until([](char c) { return c == '_' || c == '\0'; }); 338 Arch = Arch.drop_while([](char c) { return c == '_'; }); 339 } 340 } 341 342 return Features; 343 } 344 345 SubtargetFeatures ELFObjectFileBase::getFeatures() const { 346 switch (getEMachine()) { 347 case ELF::EM_MIPS: 348 return getMIPSFeatures(); 349 case ELF::EM_ARM: 350 return getARMFeatures(); 351 case ELF::EM_RISCV: 352 return getRISCVFeatures(); 353 default: 354 return SubtargetFeatures(); 355 } 356 } 357 358 Optional<StringRef> ELFObjectFileBase::tryGetCPUName() const { 359 switch (getEMachine()) { 360 case ELF::EM_AMDGPU: 361 return getAMDGPUCPUName(); 362 case ELF::EM_PPC64: 363 return StringRef("future"); 364 default: 365 return None; 366 } 367 } 368 369 StringRef ELFObjectFileBase::getAMDGPUCPUName() const { 370 assert(getEMachine() == ELF::EM_AMDGPU); 371 unsigned CPU = getPlatformFlags() & ELF::EF_AMDGPU_MACH; 372 373 switch (CPU) { 374 // Radeon HD 2000/3000 Series (R600). 375 case ELF::EF_AMDGPU_MACH_R600_R600: 376 return "r600"; 377 case ELF::EF_AMDGPU_MACH_R600_R630: 378 return "r630"; 379 case ELF::EF_AMDGPU_MACH_R600_RS880: 380 return "rs880"; 381 case ELF::EF_AMDGPU_MACH_R600_RV670: 382 return "rv670"; 383 384 // Radeon HD 4000 Series (R700). 385 case ELF::EF_AMDGPU_MACH_R600_RV710: 386 return "rv710"; 387 case ELF::EF_AMDGPU_MACH_R600_RV730: 388 return "rv730"; 389 case ELF::EF_AMDGPU_MACH_R600_RV770: 390 return "rv770"; 391 392 // Radeon HD 5000 Series (Evergreen). 393 case ELF::EF_AMDGPU_MACH_R600_CEDAR: 394 return "cedar"; 395 case ELF::EF_AMDGPU_MACH_R600_CYPRESS: 396 return "cypress"; 397 case ELF::EF_AMDGPU_MACH_R600_JUNIPER: 398 return "juniper"; 399 case ELF::EF_AMDGPU_MACH_R600_REDWOOD: 400 return "redwood"; 401 case ELF::EF_AMDGPU_MACH_R600_SUMO: 402 return "sumo"; 403 404 // Radeon HD 6000 Series (Northern Islands). 405 case ELF::EF_AMDGPU_MACH_R600_BARTS: 406 return "barts"; 407 case ELF::EF_AMDGPU_MACH_R600_CAICOS: 408 return "caicos"; 409 case ELF::EF_AMDGPU_MACH_R600_CAYMAN: 410 return "cayman"; 411 case ELF::EF_AMDGPU_MACH_R600_TURKS: 412 return "turks"; 413 414 // AMDGCN GFX6. 415 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX600: 416 return "gfx600"; 417 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX601: 418 return "gfx601"; 419 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX602: 420 return "gfx602"; 421 422 // AMDGCN GFX7. 423 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX700: 424 return "gfx700"; 425 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX701: 426 return "gfx701"; 427 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX702: 428 return "gfx702"; 429 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX703: 430 return "gfx703"; 431 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX704: 432 return "gfx704"; 433 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX705: 434 return "gfx705"; 435 436 // AMDGCN GFX8. 437 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX801: 438 return "gfx801"; 439 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX802: 440 return "gfx802"; 441 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX803: 442 return "gfx803"; 443 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX805: 444 return "gfx805"; 445 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX810: 446 return "gfx810"; 447 448 // AMDGCN GFX9. 449 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX900: 450 return "gfx900"; 451 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX902: 452 return "gfx902"; 453 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX904: 454 return "gfx904"; 455 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX906: 456 return "gfx906"; 457 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX908: 458 return "gfx908"; 459 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX909: 460 return "gfx909"; 461 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX90A: 462 return "gfx90a"; 463 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX90C: 464 return "gfx90c"; 465 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX940: 466 return "gfx940"; 467 468 // AMDGCN GFX10. 469 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1010: 470 return "gfx1010"; 471 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1011: 472 return "gfx1011"; 473 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1012: 474 return "gfx1012"; 475 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1013: 476 return "gfx1013"; 477 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1030: 478 return "gfx1030"; 479 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1031: 480 return "gfx1031"; 481 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1032: 482 return "gfx1032"; 483 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1033: 484 return "gfx1033"; 485 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1034: 486 return "gfx1034"; 487 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1035: 488 return "gfx1035"; 489 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1036: 490 return "gfx1036"; 491 492 // AMDGCN GFX11. 493 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1100: 494 return "gfx1100"; 495 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1101: 496 return "gfx1101"; 497 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1102: 498 return "gfx1102"; 499 case ELF::EF_AMDGPU_MACH_AMDGCN_GFX1103: 500 return "gfx1103"; 501 default: 502 llvm_unreachable("Unknown EF_AMDGPU_MACH value"); 503 } 504 } 505 506 // FIXME Encode from a tablegen description or target parser. 507 void ELFObjectFileBase::setARMSubArch(Triple &TheTriple) const { 508 if (TheTriple.getSubArch() != Triple::NoSubArch) 509 return; 510 511 ARMAttributeParser Attributes; 512 if (Error E = getBuildAttributes(Attributes)) { 513 // TODO Propagate Error. 514 consumeError(std::move(E)); 515 return; 516 } 517 518 std::string Triple; 519 // Default to ARM, but use the triple if it's been set. 520 if (TheTriple.isThumb()) 521 Triple = "thumb"; 522 else 523 Triple = "arm"; 524 525 Optional<unsigned> Attr = 526 Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch); 527 if (Attr) { 528 switch (Attr.value()) { 529 case ARMBuildAttrs::v4: 530 Triple += "v4"; 531 break; 532 case ARMBuildAttrs::v4T: 533 Triple += "v4t"; 534 break; 535 case ARMBuildAttrs::v5T: 536 Triple += "v5t"; 537 break; 538 case ARMBuildAttrs::v5TE: 539 Triple += "v5te"; 540 break; 541 case ARMBuildAttrs::v5TEJ: 542 Triple += "v5tej"; 543 break; 544 case ARMBuildAttrs::v6: 545 Triple += "v6"; 546 break; 547 case ARMBuildAttrs::v6KZ: 548 Triple += "v6kz"; 549 break; 550 case ARMBuildAttrs::v6T2: 551 Triple += "v6t2"; 552 break; 553 case ARMBuildAttrs::v6K: 554 Triple += "v6k"; 555 break; 556 case ARMBuildAttrs::v7: { 557 Optional<unsigned> ArchProfileAttr = 558 Attributes.getAttributeValue(ARMBuildAttrs::CPU_arch_profile); 559 if (ArchProfileAttr && 560 ArchProfileAttr.value() == ARMBuildAttrs::MicroControllerProfile) 561 Triple += "v7m"; 562 else 563 Triple += "v7"; 564 break; 565 } 566 case ARMBuildAttrs::v6_M: 567 Triple += "v6m"; 568 break; 569 case ARMBuildAttrs::v6S_M: 570 Triple += "v6sm"; 571 break; 572 case ARMBuildAttrs::v7E_M: 573 Triple += "v7em"; 574 break; 575 case ARMBuildAttrs::v8_A: 576 Triple += "v8a"; 577 break; 578 case ARMBuildAttrs::v8_R: 579 Triple += "v8r"; 580 break; 581 case ARMBuildAttrs::v8_M_Base: 582 Triple += "v8m.base"; 583 break; 584 case ARMBuildAttrs::v8_M_Main: 585 Triple += "v8m.main"; 586 break; 587 case ARMBuildAttrs::v8_1_M_Main: 588 Triple += "v8.1m.main"; 589 break; 590 case ARMBuildAttrs::v9_A: 591 Triple += "v9a"; 592 break; 593 } 594 } 595 if (!isLittleEndian()) 596 Triple += "eb"; 597 598 TheTriple.setArchName(Triple); 599 } 600 601 std::vector<std::pair<Optional<DataRefImpl>, uint64_t>> 602 ELFObjectFileBase::getPltAddresses() const { 603 std::string Err; 604 const auto Triple = makeTriple(); 605 const auto *T = TargetRegistry::lookupTarget(Triple.str(), Err); 606 if (!T) 607 return {}; 608 uint64_t JumpSlotReloc = 0; 609 switch (Triple.getArch()) { 610 case Triple::x86: 611 JumpSlotReloc = ELF::R_386_JUMP_SLOT; 612 break; 613 case Triple::x86_64: 614 JumpSlotReloc = ELF::R_X86_64_JUMP_SLOT; 615 break; 616 case Triple::aarch64: 617 case Triple::aarch64_be: 618 JumpSlotReloc = ELF::R_AARCH64_JUMP_SLOT; 619 break; 620 default: 621 return {}; 622 } 623 std::unique_ptr<const MCInstrInfo> MII(T->createMCInstrInfo()); 624 std::unique_ptr<const MCInstrAnalysis> MIA( 625 T->createMCInstrAnalysis(MII.get())); 626 if (!MIA) 627 return {}; 628 std::optional<SectionRef> Plt, RelaPlt, GotPlt; 629 for (const SectionRef &Section : sections()) { 630 Expected<StringRef> NameOrErr = Section.getName(); 631 if (!NameOrErr) { 632 consumeError(NameOrErr.takeError()); 633 continue; 634 } 635 StringRef Name = *NameOrErr; 636 637 if (Name == ".plt") 638 Plt = Section; 639 else if (Name == ".rela.plt" || Name == ".rel.plt") 640 RelaPlt = Section; 641 else if (Name == ".got.plt") 642 GotPlt = Section; 643 } 644 if (!Plt || !RelaPlt || !GotPlt) 645 return {}; 646 Expected<StringRef> PltContents = Plt->getContents(); 647 if (!PltContents) { 648 consumeError(PltContents.takeError()); 649 return {}; 650 } 651 auto PltEntries = MIA->findPltEntries(Plt->getAddress(), 652 arrayRefFromStringRef(*PltContents), 653 GotPlt->getAddress(), Triple); 654 // Build a map from GOT entry virtual address to PLT entry virtual address. 655 DenseMap<uint64_t, uint64_t> GotToPlt; 656 for (const auto &Entry : PltEntries) 657 GotToPlt.insert(std::make_pair(Entry.second, Entry.first)); 658 // Find the relocations in the dynamic relocation table that point to 659 // locations in the GOT for which we know the corresponding PLT entry. 660 std::vector<std::pair<Optional<DataRefImpl>, uint64_t>> Result; 661 for (const auto &Relocation : RelaPlt->relocations()) { 662 if (Relocation.getType() != JumpSlotReloc) 663 continue; 664 auto PltEntryIter = GotToPlt.find(Relocation.getOffset()); 665 if (PltEntryIter != GotToPlt.end()) { 666 symbol_iterator Sym = Relocation.getSymbol(); 667 if (Sym == symbol_end()) 668 Result.emplace_back(None, PltEntryIter->second); 669 else 670 Result.emplace_back(Sym->getRawDataRefImpl(), PltEntryIter->second); 671 } 672 } 673 return Result; 674 } 675 676 template <class ELFT> 677 Expected<std::vector<BBAddrMap>> static readBBAddrMapImpl( 678 const ELFFile<ELFT> &EF, Optional<unsigned> TextSectionIndex) { 679 using Elf_Shdr = typename ELFT::Shdr; 680 std::vector<BBAddrMap> BBAddrMaps; 681 const auto &Sections = cantFail(EF.sections()); 682 for (const Elf_Shdr &Sec : Sections) { 683 if (Sec.sh_type != ELF::SHT_LLVM_BB_ADDR_MAP && 684 Sec.sh_type != ELF::SHT_LLVM_BB_ADDR_MAP_V0) 685 continue; 686 if (TextSectionIndex) { 687 Expected<const Elf_Shdr *> TextSecOrErr = EF.getSection(Sec.sh_link); 688 if (!TextSecOrErr) 689 return createError("unable to get the linked-to section for " + 690 describe(EF, Sec) + ": " + 691 toString(TextSecOrErr.takeError())); 692 if (*TextSectionIndex != std::distance(Sections.begin(), *TextSecOrErr)) 693 continue; 694 } 695 Expected<std::vector<BBAddrMap>> BBAddrMapOrErr = EF.decodeBBAddrMap(Sec); 696 if (!BBAddrMapOrErr) 697 return createError("unable to read " + describe(EF, Sec) + ": " + 698 toString(BBAddrMapOrErr.takeError())); 699 std::move(BBAddrMapOrErr->begin(), BBAddrMapOrErr->end(), 700 std::back_inserter(BBAddrMaps)); 701 } 702 return BBAddrMaps; 703 } 704 705 template <class ELFT> 706 static Expected<std::vector<VersionEntry>> 707 readDynsymVersionsImpl(const ELFFile<ELFT> &EF, 708 ELFObjectFileBase::elf_symbol_iterator_range Symbols) { 709 using Elf_Shdr = typename ELFT::Shdr; 710 const Elf_Shdr *VerSec = nullptr; 711 const Elf_Shdr *VerNeedSec = nullptr; 712 const Elf_Shdr *VerDefSec = nullptr; 713 // The user should ensure sections() can't fail here. 714 for (const Elf_Shdr &Sec : cantFail(EF.sections())) { 715 if (Sec.sh_type == ELF::SHT_GNU_versym) 716 VerSec = &Sec; 717 else if (Sec.sh_type == ELF::SHT_GNU_verdef) 718 VerDefSec = &Sec; 719 else if (Sec.sh_type == ELF::SHT_GNU_verneed) 720 VerNeedSec = &Sec; 721 } 722 if (!VerSec) 723 return std::vector<VersionEntry>(); 724 725 Expected<SmallVector<Optional<VersionEntry>, 0>> MapOrErr = 726 EF.loadVersionMap(VerNeedSec, VerDefSec); 727 if (!MapOrErr) 728 return MapOrErr.takeError(); 729 730 std::vector<VersionEntry> Ret; 731 size_t I = 0; 732 for (const ELFSymbolRef &Sym : Symbols) { 733 ++I; 734 Expected<const typename ELFT::Versym *> VerEntryOrErr = 735 EF.template getEntry<typename ELFT::Versym>(*VerSec, I); 736 if (!VerEntryOrErr) 737 return createError("unable to read an entry with index " + Twine(I) + 738 " from " + describe(EF, *VerSec) + ": " + 739 toString(VerEntryOrErr.takeError())); 740 741 Expected<uint32_t> FlagsOrErr = Sym.getFlags(); 742 if (!FlagsOrErr) 743 return createError("unable to read flags for symbol with index " + 744 Twine(I) + ": " + toString(FlagsOrErr.takeError())); 745 746 bool IsDefault; 747 Expected<StringRef> VerOrErr = EF.getSymbolVersionByIndex( 748 (*VerEntryOrErr)->vs_index, IsDefault, *MapOrErr, 749 (*FlagsOrErr) & SymbolRef::SF_Undefined); 750 if (!VerOrErr) 751 return createError("unable to get a version for entry " + Twine(I) + 752 " of " + describe(EF, *VerSec) + ": " + 753 toString(VerOrErr.takeError())); 754 755 Ret.push_back({(*VerOrErr).str(), IsDefault}); 756 } 757 758 return Ret; 759 } 760 761 Expected<std::vector<VersionEntry>> 762 ELFObjectFileBase::readDynsymVersions() const { 763 elf_symbol_iterator_range Symbols = getDynamicSymbolIterators(); 764 if (const auto *Obj = dyn_cast<ELF32LEObjectFile>(this)) 765 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 766 if (const auto *Obj = dyn_cast<ELF32BEObjectFile>(this)) 767 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 768 if (const auto *Obj = dyn_cast<ELF64LEObjectFile>(this)) 769 return readDynsymVersionsImpl(Obj->getELFFile(), Symbols); 770 return readDynsymVersionsImpl(cast<ELF64BEObjectFile>(this)->getELFFile(), 771 Symbols); 772 } 773 774 Expected<std::vector<BBAddrMap>> 775 ELFObjectFileBase::readBBAddrMap(Optional<unsigned> TextSectionIndex) const { 776 if (const auto *Obj = dyn_cast<ELF32LEObjectFile>(this)) 777 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 778 if (const auto *Obj = dyn_cast<ELF64LEObjectFile>(this)) 779 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 780 if (const auto *Obj = dyn_cast<ELF32BEObjectFile>(this)) 781 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 782 if (const auto *Obj = cast<ELF64BEObjectFile>(this)) 783 return readBBAddrMapImpl(Obj->getELFFile(), TextSectionIndex); 784 else 785 llvm_unreachable("Unsupported binary format"); 786 } 787