tools/llvm-dwp/llvm-dwp.cpp

   1 //===-- llvm-dwp.cpp - Split DWARF merging tool for llvm ------------------===//
   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 // A utility for merging DWARF 5 Split DWARF .dwo files into .dwp (DWARF
  10 // package files).
  11 //
  12 //===----------------------------------------------------------------------===//
  13 #include "DWPError.h"
  14 #include "DWPStringPool.h"
  15 #include "llvm/ADT/MapVector.h"
  16 #include "llvm/ADT/Optional.h"
  17 #include "llvm/ADT/STLExtras.h"
  18 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
  19 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
  20 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
  21 #include "llvm/MC/MCAsmBackend.h"
  22 #include "llvm/MC/MCAsmInfo.h"
  23 #include "llvm/MC/MCCodeEmitter.h"
  24 #include "llvm/MC/MCContext.h"
  25 #include "llvm/MC/MCInstrInfo.h"
  26 #include "llvm/MC/MCObjectFileInfo.h"
  27 #include "llvm/MC/MCObjectWriter.h"
  28 #include "llvm/MC/MCRegisterInfo.h"
  29 #include "llvm/MC/MCStreamer.h"
  30 #include "llvm/MC/MCTargetOptionsCommandFlags.inc"
  31 #include "llvm/Object/Decompressor.h"
  32 #include "llvm/Object/ObjectFile.h"
  33 #include "llvm/Support/DataExtractor.h"
  34 #include "llvm/Support/Error.h"
  35 #include "llvm/Support/FileSystem.h"
  36 #include "llvm/Support/InitLLVM.h"
  37 #include "llvm/Support/MathExtras.h"
  38 #include "llvm/Support/MemoryBuffer.h"
  39 #include "llvm/Support/Path.h"
  40 #include "llvm/Support/TargetRegistry.h"
  41 #include "llvm/Support/TargetSelect.h"
  42 #include "llvm/Support/ToolOutputFile.h"
  43 #include "llvm/Support/WithColor.h"
  44 #include "llvm/Support/raw_ostream.h"
  45
  46 using namespace llvm;
  47 using namespace llvm::object;
  48
  49 cl::OptionCategory DwpCategory("Specific Options");
  50 static cl::list<std::string> InputFiles(cl::Positional, cl::ZeroOrMore,
  51                                         cl::desc("<input files>"),
  52                                         cl::cat(DwpCategory));
  53
  54 static cl::list<std::string> ExecFilenames(
  55     "e", cl::ZeroOrMore,
  56     cl::desc("Specify the executable/library files to get the list of *.dwo from"),
  57     cl::value_desc("filename"), cl::cat(DwpCategory));
  58
  59 static cl::opt<std::string> OutputFilename(cl::Required, "o",
  60                                            cl::desc("Specify the output file."),
  61                                            cl::value_desc("filename"),
  62                                            cl::cat(DwpCategory));
  63
  64 static void writeStringsAndOffsets(MCStreamer &Out, DWPStringPool &Strings,
  65                                    MCSection *StrOffsetSection,
  66                                    StringRef CurStrSection,
  67                                    StringRef CurStrOffsetSection) {
  68   // Could possibly produce an error or warning if one of these was non-null but
  69   // the other was null.
  70   if (CurStrSection.empty() || CurStrOffsetSection.empty())
  71     return;
  72
  73   DenseMap<uint64_t, uint32_t> OffsetRemapping;
  74
  75   DataExtractor Data(CurStrSection, true, 0);
  76   uint64_t LocalOffset = 0;
  77   uint64_t PrevOffset = 0;
  78   while (const char *s = Data.getCStr(&LocalOffset)) {
  79     OffsetRemapping[PrevOffset] =
  80         Strings.getOffset(s, LocalOffset - PrevOffset);
  81     PrevOffset = LocalOffset;
  82   }
  83
  84   Data = DataExtractor(CurStrOffsetSection, true, 0);
  85
  86   Out.SwitchSection(StrOffsetSection);
  87
  88   uint64_t Offset = 0;
  89   uint64_t Size = CurStrOffsetSection.size();
  90   while (Offset < Size) {
  91     auto OldOffset = Data.getU32(&Offset);
  92     auto NewOffset = OffsetRemapping[OldOffset];
  93     Out.EmitIntValue(NewOffset, 4);
  94   }
  95 }
  96
  97 static uint64_t getCUAbbrev(StringRef Abbrev, uint64_t AbbrCode) {
  98   uint64_t CurCode;
  99   uint64_t Offset = 0;
 100   DataExtractor AbbrevData(Abbrev, true, 0);
 101   while ((CurCode = AbbrevData.getULEB128(&Offset)) != AbbrCode) {
 102     // Tag
 103     AbbrevData.getULEB128(&Offset);
 104     // DW_CHILDREN
 105     AbbrevData.getU8(&Offset);
 106     // Attributes
 107     while (AbbrevData.getULEB128(&Offset) | AbbrevData.getULEB128(&Offset))
 108       ;
 109   }
 110   return Offset;
 111 }
 112
 113 struct CompileUnitIdentifiers {
 114   uint64_t Signature = 0;
 115   const char *Name = "";
 116   const char *DWOName = "";
 117 };
 118
 119 static Expected<const char *>
 120 getIndexedString(dwarf::Form Form, DataExtractor InfoData,
 121                  uint64_t &InfoOffset, StringRef StrOffsets, StringRef Str) {
 122   if (Form == dwarf::DW_FORM_string)
 123     return InfoData.getCStr(&InfoOffset);
 124   if (Form != dwarf::DW_FORM_GNU_str_index)
 125     return make_error<DWPError>(
 126         "string field encoded without DW_FORM_string or DW_FORM_GNU_str_index");
 127   auto StrIndex = InfoData.getULEB128(&InfoOffset);
 128   DataExtractor StrOffsetsData(StrOffsets, true, 0);
 129   uint64_t StrOffsetsOffset = 4 * StrIndex;
 130   uint64_t StrOffset = StrOffsetsData.getU32(&StrOffsetsOffset);
 131   DataExtractor StrData(Str, true, 0);
 132   return StrData.getCStr(&StrOffset);
 133 }
 134
 135 static Expected<CompileUnitIdentifiers> getCUIdentifiers(StringRef Abbrev,
 136                                                          StringRef Info,
 137                                                          StringRef StrOffsets,
 138                                                          StringRef Str) {
 139   uint64_t Offset = 0;
 140   DataExtractor InfoData(Info, true, 0);
 141   dwarf::DwarfFormat Format = dwarf::DwarfFormat::DWARF32;
 142   uint64_t Length = InfoData.getU32(&Offset);
 143   // If the length is 0xffffffff, then this indictes that this is a DWARF 64
 144   // stream and the length is actually encoded into a 64 bit value that follows.
 145   if (Length == 0xffffffffU) {
 146     Format = dwarf::DwarfFormat::DWARF64;
 147     Length = InfoData.getU64(&Offset);
 148   }
 149   uint16_t Version = InfoData.getU16(&Offset);
 150   InfoData.getU32(&Offset); // Abbrev offset (should be zero)
 151   uint8_t AddrSize = InfoData.getU8(&Offset);
 152
 153   uint32_t AbbrCode = InfoData.getULEB128(&Offset);
 154
 155   DataExtractor AbbrevData(Abbrev, true, 0);
 156   uint64_t AbbrevOffset = getCUAbbrev(Abbrev, AbbrCode);
 157   auto Tag = static_cast<dwarf::Tag>(AbbrevData.getULEB128(&AbbrevOffset));
 158   if (Tag != dwarf::DW_TAG_compile_unit)
 159     return make_error<DWPError>("top level DIE is not a compile unit");
 160   // DW_CHILDREN
 161   AbbrevData.getU8(&AbbrevOffset);
 162   uint32_t Name;
 163   dwarf::Form Form;
 164   CompileUnitIdentifiers ID;
 165   Optional<uint64_t> Signature = None;
 166   while ((Name = AbbrevData.getULEB128(&AbbrevOffset)) |
 167          (Form = static_cast<dwarf::Form>(AbbrevData.getULEB128(&AbbrevOffset))) &&
 168          (Name != 0 || Form != 0)) {
 169     switch (Name) {
 170     case dwarf::DW_AT_name: {
 171       Expected<const char *> EName =
 172           getIndexedString(Form, InfoData, Offset, StrOffsets, Str);
 173       if (!EName)
 174         return EName.takeError();
 175       ID.Name = *EName;
 176       break;
 177     }
 178     case dwarf::DW_AT_GNU_dwo_name: {
 179       Expected<const char *> EName =
 180           getIndexedString(Form, InfoData, Offset, StrOffsets, Str);
 181       if (!EName)
 182         return EName.takeError();
 183       ID.DWOName = *EName;
 184       break;
 185     }
 186     case dwarf::DW_AT_GNU_dwo_id:
 187       Signature = InfoData.getU64(&Offset);
 188       break;
 189     default:
 190       DWARFFormValue::skipValue(Form, InfoData, &Offset,
 191                                 dwarf::FormParams({Version, AddrSize, Format}));
 192     }
 193   }
 194   if (!Signature)
 195     return make_error<DWPError>("compile unit missing dwo_id");
 196   ID.Signature = *Signature;
 197   return ID;
 198 }
 199
 200 struct UnitIndexEntry {
 201   DWARFUnitIndex::Entry::SectionContribution Contributions[8];
 202   std::string Name;
 203   std::string DWOName;
 204   StringRef DWPName;
 205 };
 206
 207 static StringRef getSubsection(StringRef Section,
 208                                const DWARFUnitIndex::Entry &Entry,
 209                                DWARFSectionKind Kind) {
 210   const auto *Off = Entry.getOffset(Kind);
 211   if (!Off)
 212     return StringRef();
 213   return Section.substr(Off->Offset, Off->Length);
 214 }
 215
 216 static void addAllTypesFromDWP(
 217     MCStreamer &Out, MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
 218     const DWARFUnitIndex &TUIndex, MCSection *OutputTypes, StringRef Types,
 219     const UnitIndexEntry &TUEntry, uint32_t &TypesOffset) {
 220   Out.SwitchSection(OutputTypes);
 221   for (const DWARFUnitIndex::Entry &E : TUIndex.getRows()) {
 222     auto *I = E.getOffsets();
 223     if (!I)
 224       continue;
 225     auto P = TypeIndexEntries.insert(std::make_pair(E.getSignature(), TUEntry));
 226     if (!P.second)
 227       continue;
 228     auto &Entry = P.first->second;
 229     // Zero out the debug_info contribution
 230     Entry.Contributions[0] = {};
 231     for (auto Kind : TUIndex.getColumnKinds()) {
 232       auto &C = Entry.Contributions[Kind - DW_SECT_INFO];
 233       C.Offset += I->Offset;
 234       C.Length = I->Length;
 235       ++I;
 236     }
 237     auto &C = Entry.Contributions[DW_SECT_TYPES - DW_SECT_INFO];
 238     Out.EmitBytes(Types.substr(
 239         C.Offset - TUEntry.Contributions[DW_SECT_TYPES - DW_SECT_INFO].Offset,
 240         C.Length));
 241     C.Offset = TypesOffset;
 242     TypesOffset += C.Length;
 243   }
 244 }
 245
 246 static void addAllTypes(MCStreamer &Out,
 247                         MapVector<uint64_t, UnitIndexEntry> &TypeIndexEntries,
 248                         MCSection *OutputTypes,
 249                         const std::vector<StringRef> &TypesSections,
 250                         const UnitIndexEntry &CUEntry, uint32_t &TypesOffset) {
 251   for (StringRef Types : TypesSections) {
 252     Out.SwitchSection(OutputTypes);
 253     uint64_t Offset = 0;
 254     DataExtractor Data(Types, true, 0);
 255     while (Data.isValidOffset(Offset)) {
 256       UnitIndexEntry Entry = CUEntry;
 257       // Zero out the debug_info contribution
 258       Entry.Contributions[0] = {};
 259       auto &C = Entry.Contributions[DW_SECT_TYPES - DW_SECT_INFO];
 260       C.Offset = TypesOffset;
 261       auto PrevOffset = Offset;
 262       // Length of the unit, including the 4 byte length field.
 263       C.Length = Data.getU32(&Offset) + 4;
 264
 265       Data.getU16(&Offset); // Version
 266       Data.getU32(&Offset); // Abbrev offset
 267       Data.getU8(&Offset);  // Address size
 268       auto Signature = Data.getU64(&Offset);
 269       Offset = PrevOffset + C.Length;
 270
 271       auto P = TypeIndexEntries.insert(std::make_pair(Signature, Entry));
 272       if (!P.second)
 273         continue;
 274
 275       Out.EmitBytes(Types.substr(PrevOffset, C.Length));
 276       TypesOffset += C.Length;
 277     }
 278   }
 279 }
 280
 281 static void
 282 writeIndexTable(MCStreamer &Out, ArrayRef<unsigned> ContributionOffsets,
 283                 const MapVector<uint64_t, UnitIndexEntry> &IndexEntries,
 284                 uint32_t DWARFUnitIndex::Entry::SectionContribution::*Field) {
 285   for (const auto &E : IndexEntries)
 286     for (size_t i = 0; i != array_lengthof(E.second.Contributions); ++i)
 287       if (ContributionOffsets[i])
 288         Out.EmitIntValue(E.second.Contributions[i].*Field, 4);
 289 }
 290
 291 static void
 292 writeIndex(MCStreamer &Out, MCSection *Section,
 293            ArrayRef<unsigned> ContributionOffsets,
 294            const MapVector<uint64_t, UnitIndexEntry> &IndexEntries) {
 295   if (IndexEntries.empty())
 296     return;
 297
 298   unsigned Columns = 0;
 299   for (auto &C : ContributionOffsets)
 300     if (C)
 301       ++Columns;
 302
 303   std::vector<unsigned> Buckets(NextPowerOf2(3 * IndexEntries.size() / 2));
 304   uint64_t Mask = Buckets.size() - 1;
 305   size_t i = 0;
 306   for (const auto &P : IndexEntries) {
 307     auto S = P.first;
 308     auto H = S & Mask;
 309     auto HP = ((S >> 32) & Mask) | 1;
 310     while (Buckets[H]) {
 311       assert(S != IndexEntries.begin()[Buckets[H] - 1].first &&
 312              "Duplicate unit");
 313       H = (H + HP) & Mask;
 314     }
 315     Buckets[H] = i + 1;
 316     ++i;
 317   }
 318
 319   Out.SwitchSection(Section);
 320   Out.EmitIntValue(2, 4);                   // Version
 321   Out.EmitIntValue(Columns, 4);             // Columns
 322   Out.EmitIntValue(IndexEntries.size(), 4); // Num Units
 323   Out.EmitIntValue(Buckets.size(), 4);      // Num Buckets
 324
 325   // Write the signatures.
 326   for (const auto &I : Buckets)
 327     Out.EmitIntValue(I ? IndexEntries.begin()[I - 1].first : 0, 8);
 328
 329   // Write the indexes.
 330   for (const auto &I : Buckets)
 331     Out.EmitIntValue(I, 4);
 332
 333   // Write the column headers (which sections will appear in the table)
 334   for (size_t i = 0; i != ContributionOffsets.size(); ++i)
 335     if (ContributionOffsets[i])
 336       Out.EmitIntValue(i + DW_SECT_INFO, 4);
 337
 338   // Write the offsets.
 339   writeIndexTable(Out, ContributionOffsets, IndexEntries,
 340                   &DWARFUnitIndex::Entry::SectionContribution::Offset);
 341
 342   // Write the lengths.
 343   writeIndexTable(Out, ContributionOffsets, IndexEntries,
 344                   &DWARFUnitIndex::Entry::SectionContribution::Length);
 345 }
 346
 347 std::string buildDWODescription(StringRef Name, StringRef DWPName, StringRef DWOName) {
 348   std::string Text = "\'";
 349   Text += Name;
 350   Text += '\'';
 351   if (!DWPName.empty()) {
 352     Text += " (from ";
 353     if (!DWOName.empty()) {
 354       Text += '\'';
 355       Text += DWOName;
 356       Text += "' in ";
 357     }
 358     Text += '\'';
 359     Text += DWPName;
 360     Text += "')";
 361   }
 362   return Text;
 363 }
 364
 365 static Error createError(StringRef Name, Error E) {
 366   return make_error<DWPError>(
 367       ("failure while decompressing compressed section: '" + Name + "', " +
 368        llvm::toString(std::move(E)))
 369           .str());
 370 }
 371
 372 static Error
 373 handleCompressedSection(std::deque<SmallString<32>> &UncompressedSections,
 374                         StringRef &Name, StringRef &Contents) {
 375   if (!Decompressor::isGnuStyle(Name))
 376     return Error::success();
 377
 378   Expected<Decompressor> Dec =
 379       Decompressor::create(Name, Contents, false /*IsLE*/, false /*Is64Bit*/);
 380   if (!Dec)
 381     return createError(Name, Dec.takeError());
 382
 383   UncompressedSections.emplace_back();
 384   if (Error E = Dec->resizeAndDecompress(UncompressedSections.back()))
 385     return createError(Name, std::move(E));
 386
 387   Name = Name.substr(2); // Drop ".z"
 388   Contents = UncompressedSections.back();
 389   return Error::success();
 390 }
 391
 392 static Error handleSection(
 393     const StringMap<std::pair<MCSection *, DWARFSectionKind>> &KnownSections,
 394     const MCSection *StrSection, const MCSection *StrOffsetSection,
 395     const MCSection *TypesSection, const MCSection *CUIndexSection,
 396     const MCSection *TUIndexSection, const SectionRef &Section, MCStreamer &Out,
 397     std::deque<SmallString<32>> &UncompressedSections,
 398     uint32_t (&ContributionOffsets)[8], UnitIndexEntry &CurEntry,
 399     StringRef &CurStrSection, StringRef &CurStrOffsetSection,
 400     std::vector<StringRef> &CurTypesSection, StringRef &InfoSection,
 401     StringRef &AbbrevSection, StringRef &CurCUIndexSection,
 402     StringRef &CurTUIndexSection) {
 403   if (Section.isBSS())
 404     return Error::success();
 405
 406   if (Section.isVirtual())
 407     return Error::success();
 408
 409   Expected<StringRef> NameOrErr = Section.getName();
 410   if (!NameOrErr)
 411     return NameOrErr.takeError();
 412   StringRef Name = *NameOrErr;
 413
 414   Expected<StringRef> ContentsOrErr = Section.getContents();
 415   if (!ContentsOrErr)
 416     return ContentsOrErr.takeError();
 417   StringRef Contents = *ContentsOrErr;
 418
 419   if (auto Err = handleCompressedSection(UncompressedSections, Name, Contents))
 420     return Err;
 421
 422   Name = Name.substr(Name.find_first_not_of("._"));
 423
 424   auto SectionPair = KnownSections.find(Name);
 425   if (SectionPair == KnownSections.end())
 426     return Error::success();
 427
 428   if (DWARFSectionKind Kind = SectionPair->second.second) {
 429     auto Index = Kind - DW_SECT_INFO;
 430     if (Kind != DW_SECT_TYPES) {
 431       CurEntry.Contributions[Index].Offset = ContributionOffsets[Index];
 432       ContributionOffsets[Index] +=
 433           (CurEntry.Contributions[Index].Length = Contents.size());
 434     }
 435
 436     switch (Kind) {
 437     case DW_SECT_INFO:
 438       InfoSection = Contents;
 439       break;
 440     case DW_SECT_ABBREV:
 441       AbbrevSection = Contents;
 442       break;
 443     default:
 444       break;
 445     }
 446   }
 447
 448   MCSection *OutSection = SectionPair->second.first;
 449   if (OutSection == StrOffsetSection)
 450     CurStrOffsetSection = Contents;
 451   else if (OutSection == StrSection)
 452     CurStrSection = Contents;
 453   else if (OutSection == TypesSection)
 454     CurTypesSection.push_back(Contents);
 455   else if (OutSection == CUIndexSection)
 456     CurCUIndexSection = Contents;
 457   else if (OutSection == TUIndexSection)
 458     CurTUIndexSection = Contents;
 459   else {
 460     Out.SwitchSection(OutSection);
 461     Out.EmitBytes(Contents);
 462   }
 463   return Error::success();
 464 }
 465
 466 static Error
 467 buildDuplicateError(const std::pair<uint64_t, UnitIndexEntry> &PrevE,
 468                     const CompileUnitIdentifiers &ID, StringRef DWPName) {
 469   return make_error<DWPError>(
 470       std::string("Duplicate DWO ID (") + utohexstr(PrevE.first) + ") in " +
 471       buildDWODescription(PrevE.second.Name, PrevE.second.DWPName,
 472                           PrevE.second.DWOName) +
 473       " and " + buildDWODescription(ID.Name, DWPName, ID.DWOName));
 474 }
 475
 476 static Expected<SmallVector<std::string, 16>>
 477 getDWOFilenames(StringRef ExecFilename) {
 478   auto ErrOrObj = object::ObjectFile::createObjectFile(ExecFilename);
 479   if (!ErrOrObj)
 480     return ErrOrObj.takeError();
 481
 482   const ObjectFile &Obj = *ErrOrObj.get().getBinary();
 483   std::unique_ptr<DWARFContext> DWARFCtx = DWARFContext::create(Obj);
 484
 485   SmallVector<std::string, 16> DWOPaths;
 486   for (const auto &CU : DWARFCtx->compile_units()) {
 487     const DWARFDie &Die = CU->getUnitDIE();
 488     std::string DWOName = dwarf::toString(
 489         Die.find({dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}), "");
 490     if (DWOName.empty())
 491       continue;
 492     std::string DWOCompDir =
 493         dwarf::toString(Die.find(dwarf::DW_AT_comp_dir), "");
 494     if (!DWOCompDir.empty()) {
 495       SmallString<16> DWOPath;
 496       sys::path::append(DWOPath, DWOCompDir, DWOName);
 497       DWOPaths.emplace_back(DWOPath.data(), DWOPath.size());
 498     } else {
 499       DWOPaths.push_back(std::move(DWOName));
 500     }
 501   }
 502   return std::move(DWOPaths);
 503 }
 504
 505 static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
 506   const auto &MCOFI = *Out.getContext().getObjectFileInfo();
 507   MCSection *const StrSection = MCOFI.getDwarfStrDWOSection();
 508   MCSection *const StrOffsetSection = MCOFI.getDwarfStrOffDWOSection();
 509   MCSection *const TypesSection = MCOFI.getDwarfTypesDWOSection();
 510   MCSection *const CUIndexSection = MCOFI.getDwarfCUIndexSection();
 511   MCSection *const TUIndexSection = MCOFI.getDwarfTUIndexSection();
 512   const StringMap<std::pair<MCSection *, DWARFSectionKind>> KnownSections = {
 513       {"debug_info.dwo", {MCOFI.getDwarfInfoDWOSection(), DW_SECT_INFO}},
 514       {"debug_types.dwo", {MCOFI.getDwarfTypesDWOSection(), DW_SECT_TYPES}},
 515       {"debug_str_offsets.dwo", {StrOffsetSection, DW_SECT_STR_OFFSETS}},
 516       {"debug_str.dwo", {StrSection, static_cast<DWARFSectionKind>(0)}},
 517       {"debug_loc.dwo", {MCOFI.getDwarfLocDWOSection(), DW_SECT_LOC}},
 518       {"debug_line.dwo", {MCOFI.getDwarfLineDWOSection(), DW_SECT_LINE}},
 519       {"debug_abbrev.dwo", {MCOFI.getDwarfAbbrevDWOSection(), DW_SECT_ABBREV}},
 520       {"debug_cu_index", {CUIndexSection, static_cast<DWARFSectionKind>(0)}},
 521       {"debug_tu_index", {TUIndexSection, static_cast<DWARFSectionKind>(0)}}};
 522
 523   MapVector<uint64_t, UnitIndexEntry> IndexEntries;
 524   MapVector<uint64_t, UnitIndexEntry> TypeIndexEntries;
 525
 526   uint32_t ContributionOffsets[8] = {};
 527
 528   DWPStringPool Strings(Out, StrSection);
 529
 530   SmallVector<OwningBinary<object::ObjectFile>, 128> Objects;
 531   Objects.reserve(Inputs.size());
 532
 533   std::deque<SmallString<32>> UncompressedSections;
 534
 535   for (const auto &Input : Inputs) {
 536     auto ErrOrObj = object::ObjectFile::createObjectFile(Input);
 537     if (!ErrOrObj)
 538       return ErrOrObj.takeError();
 539
 540     auto &Obj = *ErrOrObj->getBinary();
 541     Objects.push_back(std::move(*ErrOrObj));
 542
 543     UnitIndexEntry CurEntry = {};
 544
 545     StringRef CurStrSection;
 546     StringRef CurStrOffsetSection;
 547     std::vector<StringRef> CurTypesSection;
 548     StringRef InfoSection;
 549     StringRef AbbrevSection;
 550     StringRef CurCUIndexSection;
 551     StringRef CurTUIndexSection;
 552
 553     for (const auto &Section : Obj.sections())
 554       if (auto Err = handleSection(
 555               KnownSections, StrSection, StrOffsetSection, TypesSection,
 556               CUIndexSection, TUIndexSection, Section, Out,
 557               UncompressedSections, ContributionOffsets, CurEntry,
 558               CurStrSection, CurStrOffsetSection, CurTypesSection, InfoSection,
 559               AbbrevSection, CurCUIndexSection, CurTUIndexSection))
 560         return Err;
 561
 562     if (InfoSection.empty())
 563       continue;
 564
 565     writeStringsAndOffsets(Out, Strings, StrOffsetSection, CurStrSection,
 566                            CurStrOffsetSection);
 567
 568     if (CurCUIndexSection.empty()) {
 569       Expected<CompileUnitIdentifiers> EID = getCUIdentifiers(
 570           AbbrevSection, InfoSection, CurStrOffsetSection, CurStrSection);
 571       if (!EID)
 572         return createFileError(Input, EID.takeError());
 573       const auto &ID = *EID;
 574       auto P = IndexEntries.insert(std::make_pair(ID.Signature, CurEntry));
 575       if (!P.second)
 576         return buildDuplicateError(*P.first, ID, "");
 577       P.first->second.Name = ID.Name;
 578       P.first->second.DWOName = ID.DWOName;
 579       addAllTypes(Out, TypeIndexEntries, TypesSection, CurTypesSection,
 580                   CurEntry, ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO]);
 581       continue;
 582     }
 583
 584     DWARFUnitIndex CUIndex(DW_SECT_INFO);
 585     DataExtractor CUIndexData(CurCUIndexSection, Obj.isLittleEndian(), 0);
 586     if (!CUIndex.parse(CUIndexData))
 587       return make_error<DWPError>("Failed to parse cu_index");
 588
 589     for (const DWARFUnitIndex::Entry &E : CUIndex.getRows()) {
 590       auto *I = E.getOffsets();
 591       if (!I)
 592         continue;
 593       auto P = IndexEntries.insert(std::make_pair(E.getSignature(), CurEntry));
 594       Expected<CompileUnitIdentifiers> EID = getCUIdentifiers(
 595           getSubsection(AbbrevSection, E, DW_SECT_ABBREV),
 596           getSubsection(InfoSection, E, DW_SECT_INFO),
 597           getSubsection(CurStrOffsetSection, E, DW_SECT_STR_OFFSETS),
 598           CurStrSection);
 599       if (!EID)
 600         return createFileError(Input, EID.takeError());
 601       const auto &ID = *EID;
 602       if (!P.second)
 603         return buildDuplicateError(*P.first, ID, Input);
 604       auto &NewEntry = P.first->second;
 605       NewEntry.Name = ID.Name;
 606       NewEntry.DWOName = ID.DWOName;
 607       NewEntry.DWPName = Input;
 608       for (auto Kind : CUIndex.getColumnKinds()) {
 609         auto &C = NewEntry.Contributions[Kind - DW_SECT_INFO];
 610         C.Offset += I->Offset;
 611         C.Length = I->Length;
 612         ++I;
 613       }
 614     }
 615
 616     if (!CurTypesSection.empty()) {
 617       if (CurTypesSection.size() != 1)
 618         return make_error<DWPError>("multiple type unit sections in .dwp file");
 619       DWARFUnitIndex TUIndex(DW_SECT_TYPES);
 620       DataExtractor TUIndexData(CurTUIndexSection, Obj.isLittleEndian(), 0);
 621       if (!TUIndex.parse(TUIndexData))
 622         return make_error<DWPError>("Failed to parse tu_index");
 623       addAllTypesFromDWP(Out, TypeIndexEntries, TUIndex, TypesSection,
 624                          CurTypesSection.front(), CurEntry,
 625                          ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO]);
 626     }
 627   }
 628
 629   // Lie about there being no info contributions so the TU index only includes
 630   // the type unit contribution
 631   ContributionOffsets[0] = 0;
 632   writeIndex(Out, MCOFI.getDwarfTUIndexSection(), ContributionOffsets,
 633              TypeIndexEntries);
 634
 635   // Lie about the type contribution
 636   ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO] = 0;
 637   // Unlie about the info contribution
 638   ContributionOffsets[0] = 1;
 639
 640   writeIndex(Out, MCOFI.getDwarfCUIndexSection(), ContributionOffsets,
 641              IndexEntries);
 642
 643   return Error::success();
 644 }
 645
 646 static int error(const Twine &Error, const Twine &Context) {
 647   errs() << Twine("while processing ") + Context + ":\n";
 648   errs() << Twine("error: ") + Error + "\n";
 649   return 1;
 650 }
 651
 652 int main(int argc, char **argv) {
 653   InitLLVM X(argc, argv);
 654
 655   cl::ParseCommandLineOptions(argc, argv, "merge split dwarf (.dwo) files\n");
 656
 657   llvm::InitializeAllTargetInfos();
 658   llvm::InitializeAllTargetMCs();
 659   llvm::InitializeAllTargets();
 660   llvm::InitializeAllAsmPrinters();
 661
 662   std::string ErrorStr;
 663   StringRef Context = "dwarf streamer init";
 664
 665   Triple TheTriple("x86_64-linux-gnu");
 666
 667   // Get the target.
 668   const Target *TheTarget =
 669       TargetRegistry::lookupTarget("", TheTriple, ErrorStr);
 670   if (!TheTarget)
 671     return error(ErrorStr, Context);
 672   std::string TripleName = TheTriple.getTriple();
 673
 674   // Create all the MC Objects.
 675   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
 676   if (!MRI)
 677     return error(Twine("no register info for target ") + TripleName, Context);
 678
 679   std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName));
 680   if (!MAI)
 681     return error("no asm info for target " + TripleName, Context);
 682
 683   MCObjectFileInfo MOFI;
 684   MCContext MC(MAI.get(), MRI.get(), &MOFI);
 685   MOFI.InitMCObjectFileInfo(TheTriple, /*PIC*/ false, MC);
 686
 687   std::unique_ptr<MCSubtargetInfo> MSTI(
 688       TheTarget->createMCSubtargetInfo(TripleName, "", ""));
 689   if (!MSTI)
 690     return error("no subtarget info for target " + TripleName, Context);
 691
 692   MCTargetOptions Options;
 693   auto MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, Options);
 694   if (!MAB)
 695     return error("no asm backend for target " + TripleName, Context);
 696
 697   std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());
 698   if (!MII)
 699     return error("no instr info info for target " + TripleName, Context);
 700
 701   MCCodeEmitter *MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, MC);
 702   if (!MCE)
 703     return error("no code emitter for target " + TripleName, Context);
 704
 705   // Create the output file.
 706   std::error_code EC;
 707   ToolOutputFile OutFile(OutputFilename, EC, sys::fs::OF_None);
 708   Optional<buffer_ostream> BOS;
 709   raw_pwrite_stream *OS;
 710   if (EC)
 711     return error(Twine(OutputFilename) + ": " + EC.message(), Context);
 712   if (OutFile.os().supportsSeeking()) {
 713     OS = &OutFile.os();
 714   } else {
 715     BOS.emplace(OutFile.os());
 716     OS = BOS.getPointer();
 717   }
 718
 719   MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
 720   std::unique_ptr<MCStreamer> MS(TheTarget->createMCObjectStreamer(
 721       TheTriple, MC, std::unique_ptr<MCAsmBackend>(MAB),
 722       MAB->createObjectWriter(*OS), std::unique_ptr<MCCodeEmitter>(MCE), *MSTI,
 723       MCOptions.MCRelaxAll, MCOptions.MCIncrementalLinkerCompatible,
 724       /*DWARFMustBeAtTheEnd*/ false));
 725   if (!MS)
 726     return error("no object streamer for target " + TripleName, Context);
 727
 728   std::vector<std::string> DWOFilenames = InputFiles;
 729   for (const auto &ExecFilename : ExecFilenames) {
 730     auto DWOs = getDWOFilenames(ExecFilename);
 731     if (!DWOs) {
 732       logAllUnhandledErrors(DWOs.takeError(), WithColor::error());
 733       return 1;
 734     }
 735     DWOFilenames.insert(DWOFilenames.end(),
 736                         std::make_move_iterator(DWOs->begin()),
 737                         std::make_move_iterator(DWOs->end()));
 738   }
 739
 740   if (auto Err = write(*MS, DWOFilenames)) {
 741     logAllUnhandledErrors(std::move(Err), WithColor::error());
 742     return 1;
 743   }
 744
 745   MS->Finish();
 746   OutFile.keep();
 747   return 0;
 748 }