llvm/lib/Object/ELF.cpp

   1 //===- ELF.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 #include "llvm/Object/ELF.h"
  10 #include "llvm/BinaryFormat/ELF.h"
  11 #include "llvm/Support/DataExtractor.h"
  12
  13 using namespace llvm;
  14 using namespace object;
  15
  16 #define STRINGIFY_ENUM_CASE(ns, name)                                          \
  17   case ns::name:                                                               \
  18     return #name;
  19
  20 #define ELF_RELOC(name, value) STRINGIFY_ENUM_CASE(ELF, name)
  21
  22 StringRef llvm::object::getELFRelocationTypeName(uint32_t Machine,
  23                                                  uint32_t Type) {
  24   switch (Machine) {
  25   case ELF::EM_68K:
  26     switch (Type) {
  27 #include "llvm/BinaryFormat/ELFRelocs/M68k.def"
  28     default:
  29       break;
  30     }
  31     break;
  32   case ELF::EM_X86_64:
  33     switch (Type) {
  34 #include "llvm/BinaryFormat/ELFRelocs/x86_64.def"
  35     default:
  36       break;
  37     }
  38     break;
  39   case ELF::EM_386:
  40   case ELF::EM_IAMCU:
  41     switch (Type) {
  42 #include "llvm/BinaryFormat/ELFRelocs/i386.def"
  43     default:
  44       break;
  45     }
  46     break;
  47   case ELF::EM_MIPS:
  48     switch (Type) {
  49 #include "llvm/BinaryFormat/ELFRelocs/Mips.def"
  50     default:
  51       break;
  52     }
  53     break;
  54   case ELF::EM_AARCH64:
  55     switch (Type) {
  56 #include "llvm/BinaryFormat/ELFRelocs/AArch64.def"
  57     default:
  58       break;
  59     }
  60     break;
  61   case ELF::EM_ARM:
  62     switch (Type) {
  63 #include "llvm/BinaryFormat/ELFRelocs/ARM.def"
  64     default:
  65       break;
  66     }
  67     break;
  68   case ELF::EM_ARC_COMPACT:
  69   case ELF::EM_ARC_COMPACT2:
  70     switch (Type) {
  71 #include "llvm/BinaryFormat/ELFRelocs/ARC.def"
  72     default:
  73       break;
  74     }
  75     break;
  76   case ELF::EM_AVR:
  77     switch (Type) {
  78 #include "llvm/BinaryFormat/ELFRelocs/AVR.def"
  79     default:
  80       break;
  81     }
  82     break;
  83   case ELF::EM_HEXAGON:
  84     switch (Type) {
  85 #include "llvm/BinaryFormat/ELFRelocs/Hexagon.def"
  86     default:
  87       break;
  88     }
  89     break;
  90   case ELF::EM_LANAI:
  91     switch (Type) {
  92 #include "llvm/BinaryFormat/ELFRelocs/Lanai.def"
  93     default:
  94       break;
  95     }
  96     break;
  97   case ELF::EM_PPC:
  98     switch (Type) {
  99 #include "llvm/BinaryFormat/ELFRelocs/PowerPC.def"
 100     default:
 101       break;
 102     }
 103     break;
 104   case ELF::EM_PPC64:
 105     switch (Type) {
 106 #include "llvm/BinaryFormat/ELFRelocs/PowerPC64.def"
 107     default:
 108       break;
 109     }
 110     break;
 111   case ELF::EM_RISCV:
 112     switch (Type) {
 113 #include "llvm/BinaryFormat/ELFRelocs/RISCV.def"
 114     default:
 115       break;
 116     }
 117     break;
 118   case ELF::EM_S390:
 119     switch (Type) {
 120 #include "llvm/BinaryFormat/ELFRelocs/SystemZ.def"
 121     default:
 122       break;
 123     }
 124     break;
 125   case ELF::EM_SPARC:
 126   case ELF::EM_SPARC32PLUS:
 127   case ELF::EM_SPARCV9:
 128     switch (Type) {
 129 #include "llvm/BinaryFormat/ELFRelocs/Sparc.def"
 130     default:
 131       break;
 132     }
 133     break;
 134   case ELF::EM_AMDGPU:
 135     switch (Type) {
 136 #include "llvm/BinaryFormat/ELFRelocs/AMDGPU.def"
 137     default:
 138       break;
 139     }
 140     break;
 141   case ELF::EM_BPF:
 142     switch (Type) {
 143 #include "llvm/BinaryFormat/ELFRelocs/BPF.def"
 144     default:
 145       break;
 146     }
 147     break;
 148   case ELF::EM_MSP430:
 149     switch (Type) {
 150 #include "llvm/BinaryFormat/ELFRelocs/MSP430.def"
 151     default:
 152       break;
 153     }
 154     break;
 155   case ELF::EM_VE:
 156     switch (Type) {
 157 #include "llvm/BinaryFormat/ELFRelocs/VE.def"
 158     default:
 159       break;
 160     }
 161     break;
 162   case ELF::EM_CSKY:
 163     switch (Type) {
 164 #include "llvm/BinaryFormat/ELFRelocs/CSKY.def"
 165     default:
 166       break;
 167     }
 168     break;
 169   default:
 170     break;
 171   }
 172   return "Unknown";
 173 }
 174
 175 #undef ELF_RELOC
 176
 177 uint32_t llvm::object::getELFRelativeRelocationType(uint32_t Machine) {
 178   switch (Machine) {
 179   case ELF::EM_X86_64:
 180     return ELF::R_X86_64_RELATIVE;
 181   case ELF::EM_386:
 182   case ELF::EM_IAMCU:
 183     return ELF::R_386_RELATIVE;
 184   case ELF::EM_MIPS:
 185     break;
 186   case ELF::EM_AARCH64:
 187     return ELF::R_AARCH64_RELATIVE;
 188   case ELF::EM_ARM:
 189     return ELF::R_ARM_RELATIVE;
 190   case ELF::EM_ARC_COMPACT:
 191   case ELF::EM_ARC_COMPACT2:
 192     return ELF::R_ARC_RELATIVE;
 193   case ELF::EM_AVR:
 194     break;
 195   case ELF::EM_HEXAGON:
 196     return ELF::R_HEX_RELATIVE;
 197   case ELF::EM_LANAI:
 198     break;
 199   case ELF::EM_PPC:
 200     break;
 201   case ELF::EM_PPC64:
 202     return ELF::R_PPC64_RELATIVE;
 203   case ELF::EM_RISCV:
 204     return ELF::R_RISCV_RELATIVE;
 205   case ELF::EM_S390:
 206     return ELF::R_390_RELATIVE;
 207   case ELF::EM_SPARC:
 208   case ELF::EM_SPARC32PLUS:
 209   case ELF::EM_SPARCV9:
 210     return ELF::R_SPARC_RELATIVE;
 211   case ELF::EM_CSKY:
 212     return ELF::R_CKCORE_RELATIVE;
 213   case ELF::EM_AMDGPU:
 214     break;
 215   case ELF::EM_BPF:
 216     break;
 217   default:
 218     break;
 219   }
 220   return 0;
 221 }
 222
 223 StringRef llvm::object::getELFSectionTypeName(uint32_t Machine, unsigned Type) {
 224   switch (Machine) {
 225   case ELF::EM_ARM:
 226     switch (Type) {
 227       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_EXIDX);
 228       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_PREEMPTMAP);
 229       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_ATTRIBUTES);
 230       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_DEBUGOVERLAY);
 231       STRINGIFY_ENUM_CASE(ELF, SHT_ARM_OVERLAYSECTION);
 232     }
 233     break;
 234   case ELF::EM_HEXAGON:
 235     switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_HEX_ORDERED); }
 236     break;
 237   case ELF::EM_X86_64:
 238     switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_X86_64_UNWIND); }
 239     break;
 240   case ELF::EM_MIPS:
 241   case ELF::EM_MIPS_RS3_LE:
 242     switch (Type) {
 243       STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_REGINFO);
 244       STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_OPTIONS);
 245       STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_DWARF);
 246       STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_ABIFLAGS);
 247     }
 248     break;
 249   case ELF::EM_RISCV:
 250     switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_RISCV_ATTRIBUTES); }
 251     break;
 252   default:
 253     break;
 254   }
 255
 256   switch (Type) {
 257     STRINGIFY_ENUM_CASE(ELF, SHT_NULL);
 258     STRINGIFY_ENUM_CASE(ELF, SHT_PROGBITS);
 259     STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB);
 260     STRINGIFY_ENUM_CASE(ELF, SHT_STRTAB);
 261     STRINGIFY_ENUM_CASE(ELF, SHT_RELA);
 262     STRINGIFY_ENUM_CASE(ELF, SHT_HASH);
 263     STRINGIFY_ENUM_CASE(ELF, SHT_DYNAMIC);
 264     STRINGIFY_ENUM_CASE(ELF, SHT_NOTE);
 265     STRINGIFY_ENUM_CASE(ELF, SHT_NOBITS);
 266     STRINGIFY_ENUM_CASE(ELF, SHT_REL);
 267     STRINGIFY_ENUM_CASE(ELF, SHT_SHLIB);
 268     STRINGIFY_ENUM_CASE(ELF, SHT_DYNSYM);
 269     STRINGIFY_ENUM_CASE(ELF, SHT_INIT_ARRAY);
 270     STRINGIFY_ENUM_CASE(ELF, SHT_FINI_ARRAY);
 271     STRINGIFY_ENUM_CASE(ELF, SHT_PREINIT_ARRAY);
 272     STRINGIFY_ENUM_CASE(ELF, SHT_GROUP);
 273     STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB_SHNDX);
 274     STRINGIFY_ENUM_CASE(ELF, SHT_RELR);
 275     STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_REL);
 276     STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_RELA);
 277     STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_RELR);
 278     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ODRTAB);
 279     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_LINKER_OPTIONS);
 280     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CALL_GRAPH_PROFILE);
 281     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ADDRSIG);
 282     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_DEPENDENT_LIBRARIES);
 283     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_SYMPART);
 284     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_PART_EHDR);
 285     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_PART_PHDR);
 286     STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_BB_ADDR_MAP);
 287     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_ATTRIBUTES);
 288     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_HASH);
 289     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verdef);
 290     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verneed);
 291     STRINGIFY_ENUM_CASE(ELF, SHT_GNU_versym);
 292   default:
 293     return "Unknown";
 294   }
 295 }
 296
 297 template <class ELFT>
 298 std::vector<typename ELFT::Rel>
 299 ELFFile<ELFT>::decode_relrs(Elf_Relr_Range relrs) const {
 300   // This function decodes the contents of an SHT_RELR packed relocation
 301   // section.
 302   //
 303   // Proposal for adding SHT_RELR sections to generic-abi is here:
 304   //   https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg
 305   //
 306   // The encoded sequence of Elf64_Relr entries in a SHT_RELR section looks
 307   // like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
 308   //
 309   // i.e. start with an address, followed by any number of bitmaps. The address
 310   // entry encodes 1 relocation. The subsequent bitmap entries encode up to 63
 311   // relocations each, at subsequent offsets following the last address entry.
 312   //
 313   // The bitmap entries must have 1 in the least significant bit. The assumption
 314   // here is that an address cannot have 1 in lsb. Odd addresses are not
 315   // supported.
 316   //
 317   // Excluding the least significant bit in the bitmap, each non-zero bit in
 318   // the bitmap represents a relocation to be applied to a corresponding machine
 319   // word that follows the base address word. The second least significant bit
 320   // represents the machine word immediately following the initial address, and
 321   // each bit that follows represents the next word, in linear order. As such,
 322   // a single bitmap can encode up to 31 relocations in a 32-bit object, and
 323   // 63 relocations in a 64-bit object.
 324   //
 325   // This encoding has a couple of interesting properties:
 326   // 1. Looking at any entry, it is clear whether it's an address or a bitmap:
 327   //    even means address, odd means bitmap.
 328   // 2. Just a simple list of addresses is a valid encoding.
 329
 330   Elf_Rel Rel;
 331   Rel.r_info = 0;
 332   Rel.setType(getRelativeRelocationType(), false);
 333   std::vector<Elf_Rel> Relocs;
 334
 335   // Word type: uint32_t for Elf32, and uint64_t for Elf64.
 336   typedef typename ELFT::uint Word;
 337
 338   // Word size in number of bytes.
 339   const size_t WordSize = sizeof(Word);
 340
 341   // Number of bits used for the relocation offsets bitmap.
 342   // These many relative relocations can be encoded in a single entry.
 343   const size_t NBits = 8*WordSize - 1;
 344
 345   Word Base = 0;
 346   for (const Elf_Relr &R : relrs) {
 347     Word Entry = R;
 348     if ((Entry&1) == 0) {
 349       // Even entry: encodes the offset for next relocation.
 350       Rel.r_offset = Entry;
 351       Relocs.push_back(Rel);
 352       // Set base offset for subsequent bitmap entries.
 353       Base = Entry + WordSize;
 354       continue;
 355     }
 356
 357     // Odd entry: encodes bitmap for relocations starting at base.
 358     Word Offset = Base;
 359     while (Entry != 0) {
 360       Entry >>= 1;
 361       if ((Entry&1) != 0) {
 362         Rel.r_offset = Offset;
 363         Relocs.push_back(Rel);
 364       }
 365       Offset += WordSize;
 366     }
 367
 368     // Advance base offset by NBits words.
 369     Base += NBits * WordSize;
 370   }
 371
 372   return Relocs;
 373 }
 374
 375 template <class ELFT>
 376 Expected<std::vector<typename ELFT::Rela>>
 377 ELFFile<ELFT>::android_relas(const Elf_Shdr &Sec) const {
 378   // This function reads relocations in Android's packed relocation format,
 379   // which is based on SLEB128 and delta encoding.
 380   Expected<ArrayRef<uint8_t>> ContentsOrErr = getSectionContents(Sec);
 381   if (!ContentsOrErr)
 382     return ContentsOrErr.takeError();
 383   ArrayRef<uint8_t> Content = *ContentsOrErr;
 384   if (Content.size() < 4 || Content[0] != 'A' || Content[1] != 'P' ||
 385       Content[2] != 'S' || Content[3] != '2')
 386     return createError("invalid packed relocation header");
 387   DataExtractor Data(Content, isLE(), ELFT::Is64Bits ? 8 : 4);
 388   DataExtractor::Cursor Cur(/*Offset=*/4);
 389
 390   uint64_t NumRelocs = Data.getSLEB128(Cur);
 391   uint64_t Offset = Data.getSLEB128(Cur);
 392   uint64_t Addend = 0;
 393
 394   if (!Cur)
 395     return std::move(Cur.takeError());
 396
 397   std::vector<Elf_Rela> Relocs;
 398   Relocs.reserve(NumRelocs);
 399   while (NumRelocs) {
 400     uint64_t NumRelocsInGroup = Data.getSLEB128(Cur);
 401     if (!Cur)
 402       return std::move(Cur.takeError());
 403     if (NumRelocsInGroup > NumRelocs)
 404       return createError("relocation group unexpectedly large");
 405     NumRelocs -= NumRelocsInGroup;
 406
 407     uint64_t GroupFlags = Data.getSLEB128(Cur);
 408     bool GroupedByInfo = GroupFlags & ELF::RELOCATION_GROUPED_BY_INFO_FLAG;
 409     bool GroupedByOffsetDelta = GroupFlags & ELF::RELOCATION_GROUPED_BY_OFFSET_DELTA_FLAG;
 410     bool GroupedByAddend = GroupFlags & ELF::RELOCATION_GROUPED_BY_ADDEND_FLAG;
 411     bool GroupHasAddend = GroupFlags & ELF::RELOCATION_GROUP_HAS_ADDEND_FLAG;
 412
 413     uint64_t GroupOffsetDelta;
 414     if (GroupedByOffsetDelta)
 415       GroupOffsetDelta = Data.getSLEB128(Cur);
 416
 417     uint64_t GroupRInfo;
 418     if (GroupedByInfo)
 419       GroupRInfo = Data.getSLEB128(Cur);
 420
 421     if (GroupedByAddend && GroupHasAddend)
 422       Addend += Data.getSLEB128(Cur);
 423
 424     if (!GroupHasAddend)
 425       Addend = 0;
 426
 427     for (uint64_t I = 0; Cur && I != NumRelocsInGroup; ++I) {
 428       Elf_Rela R;
 429       Offset += GroupedByOffsetDelta ? GroupOffsetDelta : Data.getSLEB128(Cur);
 430       R.r_offset = Offset;
 431       R.r_info = GroupedByInfo ? GroupRInfo : Data.getSLEB128(Cur);
 432       if (GroupHasAddend && !GroupedByAddend)
 433         Addend += Data.getSLEB128(Cur);
 434       R.r_addend = Addend;
 435       Relocs.push_back(R);
 436     }
 437     if (!Cur)
 438       return std::move(Cur.takeError());
 439   }
 440
 441   return Relocs;
 442 }
 443
 444 template <class ELFT>
 445 std::string ELFFile<ELFT>::getDynamicTagAsString(unsigned Arch,
 446                                                  uint64_t Type) const {
 447 #define DYNAMIC_STRINGIFY_ENUM(tag, value)                                     \
 448   case value:                                                                  \
 449     return #tag;
 450
 451 #define DYNAMIC_TAG(n, v)
 452   switch (Arch) {
 453   case ELF::EM_AARCH64:
 454     switch (Type) {
 455 #define AARCH64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
 456 #include "llvm/BinaryFormat/DynamicTags.def"
 457 #undef AARCH64_DYNAMIC_TAG
 458     }
 459     break;
 460
 461   case ELF::EM_HEXAGON:
 462     switch (Type) {
 463 #define HEXAGON_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
 464 #include "llvm/BinaryFormat/DynamicTags.def"
 465 #undef HEXAGON_DYNAMIC_TAG
 466     }
 467     break;
 468
 469   case ELF::EM_MIPS:
 470     switch (Type) {
 471 #define MIPS_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
 472 #include "llvm/BinaryFormat/DynamicTags.def"
 473 #undef MIPS_DYNAMIC_TAG
 474     }
 475     break;
 476
 477   case ELF::EM_PPC:
 478     switch (Type) {
 479 #define PPC_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
 480 #include "llvm/BinaryFormat/DynamicTags.def"
 481 #undef PPC_DYNAMIC_TAG
 482     }
 483     break;
 484
 485   case ELF::EM_PPC64:
 486     switch (Type) {
 487 #define PPC64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
 488 #include "llvm/BinaryFormat/DynamicTags.def"
 489 #undef PPC64_DYNAMIC_TAG
 490     }
 491     break;
 492   }
 493 #undef DYNAMIC_TAG
 494   switch (Type) {
 495 // Now handle all dynamic tags except the architecture specific ones
 496 #define AARCH64_DYNAMIC_TAG(name, value)
 497 #define MIPS_DYNAMIC_TAG(name, value)
 498 #define HEXAGON_DYNAMIC_TAG(name, value)
 499 #define PPC_DYNAMIC_TAG(name, value)
 500 #define PPC64_DYNAMIC_TAG(name, value)
 501 // Also ignore marker tags such as DT_HIOS (maps to DT_VERNEEDNUM), etc.
 502 #define DYNAMIC_TAG_MARKER(name, value)
 503 #define DYNAMIC_TAG(name, value) case value: return #name;
 504 #include "llvm/BinaryFormat/DynamicTags.def"
 505 #undef DYNAMIC_TAG
 506 #undef AARCH64_DYNAMIC_TAG
 507 #undef MIPS_DYNAMIC_TAG
 508 #undef HEXAGON_DYNAMIC_TAG
 509 #undef PPC_DYNAMIC_TAG
 510 #undef PPC64_DYNAMIC_TAG
 511 #undef DYNAMIC_TAG_MARKER
 512 #undef DYNAMIC_STRINGIFY_ENUM
 513   default:
 514     return "<unknown:>0x" + utohexstr(Type, true);
 515   }
 516 }
 517
 518 template <class ELFT>
 519 std::string ELFFile<ELFT>::getDynamicTagAsString(uint64_t Type) const {
 520   return getDynamicTagAsString(getHeader().e_machine, Type);
 521 }
 522
 523 template <class ELFT>
 524 Expected<typename ELFT::DynRange> ELFFile<ELFT>::dynamicEntries() const {
 525   ArrayRef<Elf_Dyn> Dyn;
 526
 527   auto ProgramHeadersOrError = program_headers();
 528   if (!ProgramHeadersOrError)
 529     return ProgramHeadersOrError.takeError();
 530
 531   for (const Elf_Phdr &Phdr : *ProgramHeadersOrError) {
 532     if (Phdr.p_type == ELF::PT_DYNAMIC) {
 533       Dyn = makeArrayRef(
 534           reinterpret_cast<const Elf_Dyn *>(base() + Phdr.p_offset),
 535           Phdr.p_filesz / sizeof(Elf_Dyn));
 536       break;
 537     }
 538   }
 539
 540   // If we can't find the dynamic section in the program headers, we just fall
 541   // back on the sections.
 542   if (Dyn.empty()) {
 543     auto SectionsOrError = sections();
 544     if (!SectionsOrError)
 545       return SectionsOrError.takeError();
 546
 547     for (const Elf_Shdr &Sec : *SectionsOrError) {
 548       if (Sec.sh_type == ELF::SHT_DYNAMIC) {
 549         Expected<ArrayRef<Elf_Dyn>> DynOrError =
 550             getSectionContentsAsArray<Elf_Dyn>(Sec);
 551         if (!DynOrError)
 552           return DynOrError.takeError();
 553         Dyn = *DynOrError;
 554         break;
 555       }
 556     }
 557
 558     if (!Dyn.data())
 559       return ArrayRef<Elf_Dyn>();
 560   }
 561
 562   if (Dyn.empty())
 563     // TODO: this error is untested.
 564     return createError("invalid empty dynamic section");
 565
 566   if (Dyn.back().d_tag != ELF::DT_NULL)
 567     // TODO: this error is untested.
 568     return createError("dynamic sections must be DT_NULL terminated");
 569
 570   return Dyn;
 571 }
 572
 573 template <class ELFT>
 574 Expected<const uint8_t *>
 575 ELFFile<ELFT>::toMappedAddr(uint64_t VAddr, WarningHandler WarnHandler) const {
 576   auto ProgramHeadersOrError = program_headers();
 577   if (!ProgramHeadersOrError)
 578     return ProgramHeadersOrError.takeError();
 579
 580   llvm::SmallVector<Elf_Phdr *, 4> LoadSegments;
 581
 582   for (const Elf_Phdr &Phdr : *ProgramHeadersOrError)
 583     if (Phdr.p_type == ELF::PT_LOAD)
 584       LoadSegments.push_back(const_cast<Elf_Phdr *>(&Phdr));
 585
 586   auto SortPred = [](const Elf_Phdr_Impl<ELFT> *A,
 587                      const Elf_Phdr_Impl<ELFT> *B) {
 588     return A->p_vaddr < B->p_vaddr;
 589   };
 590   if (!llvm::is_sorted(LoadSegments, SortPred)) {
 591     if (Error E =
 592             WarnHandler("loadable segments are unsorted by virtual address"))
 593       return std::move(E);
 594     llvm::stable_sort(LoadSegments, SortPred);
 595   }
 596
 597   const Elf_Phdr *const *I = llvm::upper_bound(
 598       LoadSegments, VAddr, [](uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
 599         return VAddr < Phdr->p_vaddr;
 600       });
 601
 602   if (I == LoadSegments.begin())
 603     return createError("virtual address is not in any segment: 0x" +
 604                        Twine::utohexstr(VAddr));
 605   --I;
 606   const Elf_Phdr &Phdr = **I;
 607   uint64_t Delta = VAddr - Phdr.p_vaddr;
 608   if (Delta >= Phdr.p_filesz)
 609     return createError("virtual address is not in any segment: 0x" +
 610                        Twine::utohexstr(VAddr));
 611
 612   uint64_t Offset = Phdr.p_offset + Delta;
 613   if (Offset >= getBufSize())
 614     return createError("can't map virtual address 0x" +
 615                        Twine::utohexstr(VAddr) + " to the segment with index " +
 616                        Twine(&Phdr - (*ProgramHeadersOrError).data() + 1) +
 617                        ": the segment ends at 0x" +
 618                        Twine::utohexstr(Phdr.p_offset + Phdr.p_filesz) +
 619                        ", which is greater than the file size (0x" +
 620                        Twine::utohexstr(getBufSize()) + ")");
 621
 622   return base() + Offset;
 623 }
 624
 625 template <class ELFT>
 626 Expected<std::vector<typename ELFT::BBAddrMap>>
 627 ELFFile<ELFT>::decodeBBAddrMap(const Elf_Shdr &Sec) const {
 628   Expected<ArrayRef<uint8_t>> ContentsOrErr = getSectionContents(Sec);
 629   if (!ContentsOrErr)
 630     return ContentsOrErr.takeError();
 631   ArrayRef<uint8_t> Content = *ContentsOrErr;
 632   DataExtractor Data(Content, isLE(), ELFT::Is64Bits ? 8 : 4);
 633   std::vector<Elf_BBAddrMap> FunctionEntries;
 634
 635   DataExtractor::Cursor Cur(0);
 636   Error ULEBSizeErr = Error::success();
 637
 638   // Helper to extract and decode the next ULEB128 value as uint32_t.
 639   // Returns zero and sets ULEBSizeErr if the ULEB128 value exceeds the uint32_t
 640   // limit.
 641   // Also returns zero if ULEBSizeErr is already in an error state.
 642   auto ReadULEB128AsUInt32 = [&Data, &Cur, &ULEBSizeErr]() -> uint32_t {
 643     // Bail out and do not extract data if ULEBSizeErr is already set.
 644     if (ULEBSizeErr)
 645       return 0;
 646     uint64_t Offset = Cur.tell();
 647     uint64_t Value = Data.getULEB128(Cur);
 648     if (Value > UINT32_MAX) {
 649       ULEBSizeErr = createError(
 650           "ULEB128 value at offset 0x" + Twine::utohexstr(Offset) +
 651           " exceeds UINT32_MAX (0x" + Twine::utohexstr(Value) + ")");
 652       return 0;
 653     }
 654     return static_cast<uint32_t>(Value);
 655   };
 656
 657   while (!ULEBSizeErr && Cur && Cur.tell() < Content.size()) {
 658     uintX_t Address = static_cast<uintX_t>(Data.getAddress(Cur));
 659     uint32_t NumBlocks = ReadULEB128AsUInt32();
 660     std::vector<typename Elf_BBAddrMap::BBEntry> BBEntries;
 661     for (uint32_t BlockID = 0; !ULEBSizeErr && Cur && (BlockID < NumBlocks);
 662          ++BlockID) {
 663       uint32_t Offset = ReadULEB128AsUInt32();
 664       uint32_t Size = ReadULEB128AsUInt32();
 665       uint32_t Metadata = ReadULEB128AsUInt32();
 666       BBEntries.push_back({Offset, Size, Metadata});
 667     }
 668     FunctionEntries.push_back({Address, BBEntries});
 669   }
 670   // Either Cur is in the error state, or ULEBSizeError is set (not both), but
 671   // we join the two errors here to be safe.
 672   if (!Cur || ULEBSizeErr)
 673     return joinErrors(Cur.takeError(), std::move(ULEBSizeErr));
 674   return FunctionEntries;
 675 }
 676
 677 template class llvm::object::ELFFile<ELF32LE>;
 678 template class llvm::object::ELFFile<ELF32BE>;
 679 template class llvm::object::ELFFile<ELF64LE>;
 680 template class llvm::object::ELFFile<ELF64BE>;