tools/dsymutil/DwarfStreamer.cpp

   1 //===- tools/dsymutil/DwarfStreamer.cpp - Dwarf Streamer ------------------===//
   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 "DwarfStreamer.h"
  10 #include "CompileUnit.h"
  11 #include "LinkUtils.h"
  12 #include "MachOUtils.h"
  13 #include "llvm/ADT/Triple.h"
  14 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
  15 #include "llvm/MC/MCTargetOptions.h"
  16 #include "llvm/MC/MCTargetOptionsCommandFlags.inc"
  17 #include "llvm/Support/LEB128.h"
  18 #include "llvm/Support/TargetRegistry.h"
  19 #include "llvm/Target/TargetMachine.h"
  20 #include "llvm/Target/TargetOptions.h"
  21
  22 namespace llvm {
  23 namespace dsymutil {
  24
  25 /// Retrieve the section named \a SecName in \a Obj.
  26 ///
  27 /// To accommodate for platform discrepancies, the name passed should be
  28 /// (for example) 'debug_info' to match either '__debug_info' or '.debug_info'.
  29 /// This function will strip the initial platform-specific characters.
  30 static Optional<object::SectionRef>
  31 getSectionByName(const object::ObjectFile &Obj, StringRef SecName) {
  32   for (const object::SectionRef &Section : Obj.sections()) {
  33     StringRef SectionName;
  34     Section.getName(SectionName);
  35     SectionName = SectionName.substr(SectionName.find_first_not_of("._"));
  36     if (SectionName != SecName)
  37       continue;
  38     return Section;
  39   }
  40   return None;
  41 }
  42
  43 bool DwarfStreamer::init(Triple TheTriple) {
  44   std::string ErrorStr;
  45   std::string TripleName;
  46   StringRef Context = "dwarf streamer init";
  47
  48   // Get the target.
  49   const Target *TheTarget =
  50       TargetRegistry::lookupTarget(TripleName, TheTriple, ErrorStr);
  51   if (!TheTarget)
  52     return error(ErrorStr, Context);
  53   TripleName = TheTriple.getTriple();
  54
  55   // Create all the MC Objects.
  56   MRI.reset(TheTarget->createMCRegInfo(TripleName));
  57   if (!MRI)
  58     return error(Twine("no register info for target ") + TripleName, Context);
  59
  60   MAI.reset(TheTarget->createMCAsmInfo(*MRI, TripleName));
  61   if (!MAI)
  62     return error("no asm info for target " + TripleName, Context);
  63
  64   MOFI.reset(new MCObjectFileInfo);
  65   MC.reset(new MCContext(MAI.get(), MRI.get(), MOFI.get()));
  66   MOFI->InitMCObjectFileInfo(TheTriple, /*PIC*/ false, *MC);
  67
  68   MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
  69   if (!MSTI)
  70     return error("no subtarget info for target " + TripleName, Context);
  71
  72   MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
  73   MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, MCOptions);
  74   if (!MAB)
  75     return error("no asm backend for target " + TripleName, Context);
  76
  77   MII.reset(TheTarget->createMCInstrInfo());
  78   if (!MII)
  79     return error("no instr info info for target " + TripleName, Context);
  80
  81   MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, *MC);
  82   if (!MCE)
  83     return error("no code emitter for target " + TripleName, Context);
  84
  85   switch (Options.FileType) {
  86   case OutputFileType::Assembly: {
  87     MIP = TheTarget->createMCInstPrinter(TheTriple, MAI->getAssemblerDialect(),
  88                                          *MAI, *MII, *MRI);
  89     MS = TheTarget->createAsmStreamer(
  90         *MC, llvm::make_unique<formatted_raw_ostream>(OutFile), true, true, MIP,
  91         std::unique_ptr<MCCodeEmitter>(MCE), std::unique_ptr<MCAsmBackend>(MAB),
  92         true);
  93     break;
  94   }
  95   case OutputFileType::Object: {
  96     MS = TheTarget->createMCObjectStreamer(
  97         TheTriple, *MC, std::unique_ptr<MCAsmBackend>(MAB),
  98         MAB->createObjectWriter(OutFile), std::unique_ptr<MCCodeEmitter>(MCE),
  99         *MSTI, MCOptions.MCRelaxAll, MCOptions.MCIncrementalLinkerCompatible,
 100         /*DWARFMustBeAtTheEnd*/ false);
 101     break;
 102   }
 103   }
 104
 105   if (!MS)
 106     return error("no object streamer for target " + TripleName, Context);
 107
 108   // Finally create the AsmPrinter we'll use to emit the DIEs.
 109   TM.reset(TheTarget->createTargetMachine(TripleName, "", "", TargetOptions(),
 110                                           None));
 111   if (!TM)
 112     return error("no target machine for target " + TripleName, Context);
 113
 114   Asm.reset(TheTarget->createAsmPrinter(*TM, std::unique_ptr<MCStreamer>(MS)));
 115   if (!Asm)
 116     return error("no asm printer for target " + TripleName, Context);
 117
 118   RangesSectionSize = 0;
 119   LocSectionSize = 0;
 120   LineSectionSize = 0;
 121   FrameSectionSize = 0;
 122
 123   return true;
 124 }
 125
 126 bool DwarfStreamer::finish(const DebugMap &DM, SymbolMapTranslator &T) {
 127   bool Result = true;
 128   if (DM.getTriple().isOSDarwin() && !DM.getBinaryPath().empty() &&
 129       Options.FileType == OutputFileType::Object)
 130     Result = MachOUtils::generateDsymCompanion(DM, T, *MS, OutFile);
 131   else
 132     MS->Finish();
 133   return Result;
 134 }
 135
 136 void DwarfStreamer::switchToDebugInfoSection(unsigned DwarfVersion) {
 137   MS->SwitchSection(MOFI->getDwarfInfoSection());
 138   MC->setDwarfVersion(DwarfVersion);
 139 }
 140
 141 /// Emit the compilation unit header for \p Unit in the debug_info section.
 142 ///
 143 /// A Dwarf section header is encoded as:
 144 ///  uint32_t   Unit length (omitting this field)
 145 ///  uint16_t   Version
 146 ///  uint32_t   Abbreviation table offset
 147 ///  uint8_t    Address size
 148 ///
 149 /// Leading to a total of 11 bytes.
 150 void DwarfStreamer::emitCompileUnitHeader(CompileUnit &Unit) {
 151   unsigned Version = Unit.getOrigUnit().getVersion();
 152   switchToDebugInfoSection(Version);
 153
 154   /// The start of the unit within its section.
 155   Unit.setLabelBegin(Asm->createTempSymbol("cu_begin"));
 156   Asm->OutStreamer->EmitLabel(Unit.getLabelBegin());
 157
 158   // Emit size of content not including length itself. The size has already
 159   // been computed in CompileUnit::computeOffsets(). Subtract 4 to that size to
 160   // account for the length field.
 161   Asm->emitInt32(Unit.getNextUnitOffset() - Unit.getStartOffset() - 4);
 162   Asm->emitInt16(Version);
 163
 164   // We share one abbreviations table across all units so it's always at the
 165   // start of the section.
 166   Asm->emitInt32(0);
 167   Asm->emitInt8(Unit.getOrigUnit().getAddressByteSize());
 168
 169   // Remember this CU.
 170   EmittedUnits.push_back({Unit.getUniqueID(), Unit.getLabelBegin()});
 171 }
 172
 173 /// Emit the \p Abbrevs array as the shared abbreviation table
 174 /// for the linked Dwarf file.
 175 void DwarfStreamer::emitAbbrevs(
 176     const std::vector<std::unique_ptr<DIEAbbrev>> &Abbrevs,
 177     unsigned DwarfVersion) {
 178   MS->SwitchSection(MOFI->getDwarfAbbrevSection());
 179   MC->setDwarfVersion(DwarfVersion);
 180   Asm->emitDwarfAbbrevs(Abbrevs);
 181 }
 182
 183 /// Recursively emit the DIE tree rooted at \p Die.
 184 void DwarfStreamer::emitDIE(DIE &Die) {
 185   MS->SwitchSection(MOFI->getDwarfInfoSection());
 186   Asm->emitDwarfDIE(Die);
 187 }
 188
 189 /// Emit the debug_str section stored in \p Pool.
 190 void DwarfStreamer::emitStrings(const NonRelocatableStringpool &Pool) {
 191   Asm->OutStreamer->SwitchSection(MOFI->getDwarfStrSection());
 192   std::vector<DwarfStringPoolEntryRef> Entries = Pool.getEntriesForEmission();
 193   for (auto Entry : Entries) {
 194     // Emit the string itself.
 195     Asm->OutStreamer->EmitBytes(Entry.getString());
 196     // Emit a null terminator.
 197     Asm->emitInt8(0);
 198   }
 199 }
 200
 201 void DwarfStreamer::emitDebugNames(
 202     AccelTable<DWARF5AccelTableStaticData> &Table) {
 203   if (EmittedUnits.empty())
 204     return;
 205
 206   // Build up data structures needed to emit this section.
 207   std::vector<MCSymbol *> CompUnits;
 208   DenseMap<unsigned, size_t> UniqueIdToCuMap;
 209   unsigned Id = 0;
 210   for (auto &CU : EmittedUnits) {
 211     CompUnits.push_back(CU.LabelBegin);
 212     // We might be omitting CUs, so we need to remap them.
 213     UniqueIdToCuMap[CU.ID] = Id++;
 214   }
 215
 216   Asm->OutStreamer->SwitchSection(MOFI->getDwarfDebugNamesSection());
 217   emitDWARF5AccelTable(
 218       Asm.get(), Table, CompUnits,
 219       [&UniqueIdToCuMap](const DWARF5AccelTableStaticData &Entry) {
 220         return UniqueIdToCuMap[Entry.getCUIndex()];
 221       });
 222 }
 223
 224 void DwarfStreamer::emitAppleNamespaces(
 225     AccelTable<AppleAccelTableStaticOffsetData> &Table) {
 226   Asm->OutStreamer->SwitchSection(MOFI->getDwarfAccelNamespaceSection());
 227   auto *SectionBegin = Asm->createTempSymbol("namespac_begin");
 228   Asm->OutStreamer->EmitLabel(SectionBegin);
 229   emitAppleAccelTable(Asm.get(), Table, "namespac", SectionBegin);
 230 }
 231
 232 void DwarfStreamer::emitAppleNames(
 233     AccelTable<AppleAccelTableStaticOffsetData> &Table) {
 234   Asm->OutStreamer->SwitchSection(MOFI->getDwarfAccelNamesSection());
 235   auto *SectionBegin = Asm->createTempSymbol("names_begin");
 236   Asm->OutStreamer->EmitLabel(SectionBegin);
 237   emitAppleAccelTable(Asm.get(), Table, "names", SectionBegin);
 238 }
 239
 240 void DwarfStreamer::emitAppleObjc(
 241     AccelTable<AppleAccelTableStaticOffsetData> &Table) {
 242   Asm->OutStreamer->SwitchSection(MOFI->getDwarfAccelObjCSection());
 243   auto *SectionBegin = Asm->createTempSymbol("objc_begin");
 244   Asm->OutStreamer->EmitLabel(SectionBegin);
 245   emitAppleAccelTable(Asm.get(), Table, "objc", SectionBegin);
 246 }
 247
 248 void DwarfStreamer::emitAppleTypes(
 249     AccelTable<AppleAccelTableStaticTypeData> &Table) {
 250   Asm->OutStreamer->SwitchSection(MOFI->getDwarfAccelTypesSection());
 251   auto *SectionBegin = Asm->createTempSymbol("types_begin");
 252   Asm->OutStreamer->EmitLabel(SectionBegin);
 253   emitAppleAccelTable(Asm.get(), Table, "types", SectionBegin);
 254 }
 255
 256 /// Emit the swift_ast section stored in \p Buffers.
 257 void DwarfStreamer::emitSwiftAST(StringRef Buffer) {
 258   MCSection *SwiftASTSection = MOFI->getDwarfSwiftASTSection();
 259   SwiftASTSection->setAlignment(1 << 5);
 260   MS->SwitchSection(SwiftASTSection);
 261   MS->EmitBytes(Buffer);
 262 }
 263
 264 /// Emit the debug_range section contents for \p FuncRange by
 265 /// translating the original \p Entries. The debug_range section
 266 /// format is totally trivial, consisting just of pairs of address
 267 /// sized addresses describing the ranges.
 268 void DwarfStreamer::emitRangesEntries(
 269     int64_t UnitPcOffset, uint64_t OrigLowPc,
 270     const FunctionIntervals::const_iterator &FuncRange,
 271     const std::vector<DWARFDebugRangeList::RangeListEntry> &Entries,
 272     unsigned AddressSize) {
 273   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection());
 274
 275   // Offset each range by the right amount.
 276   int64_t PcOffset = Entries.empty() ? 0 : FuncRange.value() + UnitPcOffset;
 277   for (const auto &Range : Entries) {
 278     if (Range.isBaseAddressSelectionEntry(AddressSize)) {
 279       warn("unsupported base address selection operation",
 280            "emitting debug_ranges");
 281       break;
 282     }
 283     // Do not emit empty ranges.
 284     if (Range.StartAddress == Range.EndAddress)
 285       continue;
 286
 287     // All range entries should lie in the function range.
 288     if (!(Range.StartAddress + OrigLowPc >= FuncRange.start() &&
 289           Range.EndAddress + OrigLowPc <= FuncRange.stop()))
 290       warn("inconsistent range data.", "emitting debug_ranges");
 291     MS->EmitIntValue(Range.StartAddress + PcOffset, AddressSize);
 292     MS->EmitIntValue(Range.EndAddress + PcOffset, AddressSize);
 293     RangesSectionSize += 2 * AddressSize;
 294   }
 295
 296   // Add the terminator entry.
 297   MS->EmitIntValue(0, AddressSize);
 298   MS->EmitIntValue(0, AddressSize);
 299   RangesSectionSize += 2 * AddressSize;
 300 }
 301
 302 /// Emit the debug_aranges contribution of a unit and
 303 /// if \p DoDebugRanges is true the debug_range contents for a
 304 /// compile_unit level DW_AT_ranges attribute (Which are basically the
 305 /// same thing with a different base address).
 306 /// Just aggregate all the ranges gathered inside that unit.
 307 void DwarfStreamer::emitUnitRangesEntries(CompileUnit &Unit,
 308                                           bool DoDebugRanges) {
 309   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
 310   // Gather the ranges in a vector, so that we can simplify them. The
 311   // IntervalMap will have coalesced the non-linked ranges, but here
 312   // we want to coalesce the linked addresses.
 313   std::vector<std::pair<uint64_t, uint64_t>> Ranges;
 314   const auto &FunctionRanges = Unit.getFunctionRanges();
 315   for (auto Range = FunctionRanges.begin(), End = FunctionRanges.end();
 316        Range != End; ++Range)
 317     Ranges.push_back(std::make_pair(Range.start() + Range.value(),
 318                                     Range.stop() + Range.value()));
 319
 320   // The object addresses where sorted, but again, the linked
 321   // addresses might end up in a different order.
 322   llvm::sort(Ranges);
 323
 324   if (!Ranges.empty()) {
 325     MS->SwitchSection(MC->getObjectFileInfo()->getDwarfARangesSection());
 326
 327     MCSymbol *BeginLabel = Asm->createTempSymbol("Barange");
 328     MCSymbol *EndLabel = Asm->createTempSymbol("Earange");
 329
 330     unsigned HeaderSize =
 331         sizeof(int32_t) + // Size of contents (w/o this field
 332         sizeof(int16_t) + // DWARF ARange version number
 333         sizeof(int32_t) + // Offset of CU in the .debug_info section
 334         sizeof(int8_t) +  // Pointer Size (in bytes)
 335         sizeof(int8_t);   // Segment Size (in bytes)
 336
 337     unsigned TupleSize = AddressSize * 2;
 338     unsigned Padding = OffsetToAlignment(HeaderSize, TupleSize);
 339
 340     Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); // Arange length
 341     Asm->OutStreamer->EmitLabel(BeginLabel);
 342     Asm->emitInt16(dwarf::DW_ARANGES_VERSION); // Version number
 343     Asm->emitInt32(Unit.getStartOffset());     // Corresponding unit's offset
 344     Asm->emitInt8(AddressSize);                // Address size
 345     Asm->emitInt8(0);                          // Segment size
 346
 347     Asm->OutStreamer->emitFill(Padding, 0x0);
 348
 349     for (auto Range = Ranges.begin(), End = Ranges.end(); Range != End;
 350          ++Range) {
 351       uint64_t RangeStart = Range->first;
 352       MS->EmitIntValue(RangeStart, AddressSize);
 353       while ((Range + 1) != End && Range->second == (Range + 1)->first)
 354         ++Range;
 355       MS->EmitIntValue(Range->second - RangeStart, AddressSize);
 356     }
 357
 358     // Emit terminator
 359     Asm->OutStreamer->EmitIntValue(0, AddressSize);
 360     Asm->OutStreamer->EmitIntValue(0, AddressSize);
 361     Asm->OutStreamer->EmitLabel(EndLabel);
 362   }
 363
 364   if (!DoDebugRanges)
 365     return;
 366
 367   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection());
 368   // Offset each range by the right amount.
 369   int64_t PcOffset = -Unit.getLowPc();
 370   // Emit coalesced ranges.
 371   for (auto Range = Ranges.begin(), End = Ranges.end(); Range != End; ++Range) {
 372     MS->EmitIntValue(Range->first + PcOffset, AddressSize);
 373     while (Range + 1 != End && Range->second == (Range + 1)->first)
 374       ++Range;
 375     MS->EmitIntValue(Range->second + PcOffset, AddressSize);
 376     RangesSectionSize += 2 * AddressSize;
 377   }
 378
 379   // Add the terminator entry.
 380   MS->EmitIntValue(0, AddressSize);
 381   MS->EmitIntValue(0, AddressSize);
 382   RangesSectionSize += 2 * AddressSize;
 383 }
 384
 385 /// Emit location lists for \p Unit and update attributes to point to the new
 386 /// entries.
 387 void DwarfStreamer::emitLocationsForUnit(const CompileUnit &Unit,
 388                                          DWARFContext &Dwarf) {
 389   const auto &Attributes = Unit.getLocationAttributes();
 390
 391   if (Attributes.empty())
 392     return;
 393
 394   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLocSection());
 395
 396   unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
 397   const DWARFSection &InputSec = Dwarf.getDWARFObj().getLocSection();
 398   DataExtractor Data(InputSec.Data, Dwarf.isLittleEndian(), AddressSize);
 399   DWARFUnit &OrigUnit = Unit.getOrigUnit();
 400   auto OrigUnitDie = OrigUnit.getUnitDIE(false);
 401   int64_t UnitPcOffset = 0;
 402   if (auto OrigLowPc = dwarf::toAddress(OrigUnitDie.find(dwarf::DW_AT_low_pc)))
 403     UnitPcOffset = int64_t(*OrigLowPc) - Unit.getLowPc();
 404
 405   for (const auto &Attr : Attributes) {
 406     uint32_t Offset = Attr.first.get();
 407     Attr.first.set(LocSectionSize);
 408     // This is the quantity to add to the old location address to get
 409     // the correct address for the new one.
 410     int64_t LocPcOffset = Attr.second + UnitPcOffset;
 411     while (Data.isValidOffset(Offset)) {
 412       uint64_t Low = Data.getUnsigned(&Offset, AddressSize);
 413       uint64_t High = Data.getUnsigned(&Offset, AddressSize);
 414       LocSectionSize += 2 * AddressSize;
 415       if (Low == 0 && High == 0) {
 416         Asm->OutStreamer->EmitIntValue(0, AddressSize);
 417         Asm->OutStreamer->EmitIntValue(0, AddressSize);
 418         break;
 419       }
 420       Asm->OutStreamer->EmitIntValue(Low + LocPcOffset, AddressSize);
 421       Asm->OutStreamer->EmitIntValue(High + LocPcOffset, AddressSize);
 422       uint64_t Length = Data.getU16(&Offset);
 423       Asm->OutStreamer->EmitIntValue(Length, 2);
 424       // Just copy the bytes over.
 425       Asm->OutStreamer->EmitBytes(
 426           StringRef(InputSec.Data.substr(Offset, Length)));
 427       Offset += Length;
 428       LocSectionSize += Length + 2;
 429     }
 430   }
 431 }
 432
 433 void DwarfStreamer::emitLineTableForUnit(MCDwarfLineTableParams Params,
 434                                          StringRef PrologueBytes,
 435                                          unsigned MinInstLength,
 436                                          std::vector<DWARFDebugLine::Row> &Rows,
 437                                          unsigned PointerSize) {
 438   // Switch to the section where the table will be emitted into.
 439   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLineSection());
 440   MCSymbol *LineStartSym = MC->createTempSymbol();
 441   MCSymbol *LineEndSym = MC->createTempSymbol();
 442
 443   // The first 4 bytes is the total length of the information for this
 444   // compilation unit (not including these 4 bytes for the length).
 445   Asm->EmitLabelDifference(LineEndSym, LineStartSym, 4);
 446   Asm->OutStreamer->EmitLabel(LineStartSym);
 447   // Copy Prologue.
 448   MS->EmitBytes(PrologueBytes);
 449   LineSectionSize += PrologueBytes.size() + 4;
 450
 451   SmallString<128> EncodingBuffer;
 452   raw_svector_ostream EncodingOS(EncodingBuffer);
 453
 454   if (Rows.empty()) {
 455     // We only have the dummy entry, dsymutil emits an entry with a 0
 456     // address in that case.
 457     MCDwarfLineAddr::Encode(*MC, Params, std::numeric_limits<int64_t>::max(), 0,
 458                             EncodingOS);
 459     MS->EmitBytes(EncodingOS.str());
 460     LineSectionSize += EncodingBuffer.size();
 461     MS->EmitLabel(LineEndSym);
 462     return;
 463   }
 464
 465   // Line table state machine fields
 466   unsigned FileNum = 1;
 467   unsigned LastLine = 1;
 468   unsigned Column = 0;
 469   unsigned IsStatement = 1;
 470   unsigned Isa = 0;
 471   uint64_t Address = -1ULL;
 472
 473   unsigned RowsSinceLastSequence = 0;
 474
 475   for (unsigned Idx = 0; Idx < Rows.size(); ++Idx) {
 476     auto &Row = Rows[Idx];
 477
 478     int64_t AddressDelta;
 479     if (Address == -1ULL) {
 480       MS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
 481       MS->EmitULEB128IntValue(PointerSize + 1);
 482       MS->EmitIntValue(dwarf::DW_LNE_set_address, 1);
 483       MS->EmitIntValue(Row.Address, PointerSize);
 484       LineSectionSize += 2 + PointerSize + getULEB128Size(PointerSize + 1);
 485       AddressDelta = 0;
 486     } else {
 487       AddressDelta = (Row.Address - Address) / MinInstLength;
 488     }
 489
 490     // FIXME: code copied and transformed from MCDwarf.cpp::EmitDwarfLineTable.
 491     // We should find a way to share this code, but the current compatibility
 492     // requirement with classic dsymutil makes it hard. Revisit that once this
 493     // requirement is dropped.
 494
 495     if (FileNum != Row.File) {
 496       FileNum = Row.File;
 497       MS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
 498       MS->EmitULEB128IntValue(FileNum);
 499       LineSectionSize += 1 + getULEB128Size(FileNum);
 500     }
 501     if (Column != Row.Column) {
 502       Column = Row.Column;
 503       MS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
 504       MS->EmitULEB128IntValue(Column);
 505       LineSectionSize += 1 + getULEB128Size(Column);
 506     }
 507
 508     // FIXME: We should handle the discriminator here, but dsymutil doesn't
 509     // consider it, thus ignore it for now.
 510
 511     if (Isa != Row.Isa) {
 512       Isa = Row.Isa;
 513       MS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
 514       MS->EmitULEB128IntValue(Isa);
 515       LineSectionSize += 1 + getULEB128Size(Isa);
 516     }
 517     if (IsStatement != Row.IsStmt) {
 518       IsStatement = Row.IsStmt;
 519       MS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
 520       LineSectionSize += 1;
 521     }
 522     if (Row.BasicBlock) {
 523       MS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
 524       LineSectionSize += 1;
 525     }
 526
 527     if (Row.PrologueEnd) {
 528       MS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
 529       LineSectionSize += 1;
 530     }
 531
 532     if (Row.EpilogueBegin) {
 533       MS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
 534       LineSectionSize += 1;
 535     }
 536
 537     int64_t LineDelta = int64_t(Row.Line) - LastLine;
 538     if (!Row.EndSequence) {
 539       MCDwarfLineAddr::Encode(*MC, Params, LineDelta, AddressDelta, EncodingOS);
 540       MS->EmitBytes(EncodingOS.str());
 541       LineSectionSize += EncodingBuffer.size();
 542       EncodingBuffer.resize(0);
 543       Address = Row.Address;
 544       LastLine = Row.Line;
 545       RowsSinceLastSequence++;
 546     } else {
 547       if (LineDelta) {
 548         MS->EmitIntValue(dwarf::DW_LNS_advance_line, 1);
 549         MS->EmitSLEB128IntValue(LineDelta);
 550         LineSectionSize += 1 + getSLEB128Size(LineDelta);
 551       }
 552       if (AddressDelta) {
 553         MS->EmitIntValue(dwarf::DW_LNS_advance_pc, 1);
 554         MS->EmitULEB128IntValue(AddressDelta);
 555         LineSectionSize += 1 + getULEB128Size(AddressDelta);
 556       }
 557       MCDwarfLineAddr::Encode(*MC, Params, std::numeric_limits<int64_t>::max(),
 558                               0, EncodingOS);
 559       MS->EmitBytes(EncodingOS.str());
 560       LineSectionSize += EncodingBuffer.size();
 561       EncodingBuffer.resize(0);
 562       Address = -1ULL;
 563       LastLine = FileNum = IsStatement = 1;
 564       RowsSinceLastSequence = Column = Isa = 0;
 565     }
 566   }
 567
 568   if (RowsSinceLastSequence) {
 569     MCDwarfLineAddr::Encode(*MC, Params, std::numeric_limits<int64_t>::max(), 0,
 570                             EncodingOS);
 571     MS->EmitBytes(EncodingOS.str());
 572     LineSectionSize += EncodingBuffer.size();
 573     EncodingBuffer.resize(0);
 574   }
 575
 576   MS->EmitLabel(LineEndSym);
 577 }
 578
 579 /// Copy the debug_line over to the updated binary while unobfuscating the file
 580 /// names and directories.
 581 void DwarfStreamer::translateLineTable(DataExtractor Data, uint32_t Offset,
 582                                        LinkOptions &Options) {
 583   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLineSection());
 584   StringRef Contents = Data.getData();
 585
 586   // We have to deconstruct the line table header, because it contains to
 587   // length fields that will need to be updated when we change the length of
 588   // the files and directories in there.
 589   unsigned UnitLength = Data.getU32(&Offset);
 590   unsigned UnitEnd = Offset + UnitLength;
 591   MCSymbol *BeginLabel = MC->createTempSymbol();
 592   MCSymbol *EndLabel = MC->createTempSymbol();
 593   unsigned Version = Data.getU16(&Offset);
 594
 595   if (Version > 5) {
 596     warn("Unsupported line table version: dropping contents and not "
 597          "unobfsucating line table.");
 598     return;
 599   }
 600
 601   Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
 602   Asm->OutStreamer->EmitLabel(BeginLabel);
 603   Asm->emitInt16(Version);
 604   LineSectionSize += 6;
 605
 606   MCSymbol *HeaderBeginLabel = MC->createTempSymbol();
 607   MCSymbol *HeaderEndLabel = MC->createTempSymbol();
 608   Asm->EmitLabelDifference(HeaderEndLabel, HeaderBeginLabel, 4);
 609   Asm->OutStreamer->EmitLabel(HeaderBeginLabel);
 610   Offset += 4;
 611   LineSectionSize += 4;
 612
 613   uint32_t AfterHeaderLengthOffset = Offset;
 614   // Skip to the directories.
 615   Offset += (Version >= 4) ? 5 : 4;
 616   unsigned OpcodeBase = Data.getU8(&Offset);
 617   Offset += OpcodeBase - 1;
 618   Asm->OutStreamer->EmitBytes(Contents.slice(AfterHeaderLengthOffset, Offset));
 619   LineSectionSize += Offset - AfterHeaderLengthOffset;
 620
 621   // Offset points to the first directory.
 622   while (const char *Dir = Data.getCStr(&Offset)) {
 623     if (Dir[0] == 0)
 624       break;
 625
 626     StringRef Translated = Options.Translator(Dir);
 627     Asm->OutStreamer->EmitBytes(Translated);
 628     Asm->emitInt8(0);
 629     LineSectionSize += Translated.size() + 1;
 630   }
 631   Asm->emitInt8(0);
 632   LineSectionSize += 1;
 633
 634   while (const char *File = Data.getCStr(&Offset)) {
 635     if (File[0] == 0)
 636       break;
 637
 638     StringRef Translated = Options.Translator(File);
 639     Asm->OutStreamer->EmitBytes(Translated);
 640     Asm->emitInt8(0);
 641     LineSectionSize += Translated.size() + 1;
 642
 643     uint32_t OffsetBeforeLEBs = Offset;
 644     Asm->EmitULEB128(Data.getULEB128(&Offset));
 645     Asm->EmitULEB128(Data.getULEB128(&Offset));
 646     Asm->EmitULEB128(Data.getULEB128(&Offset));
 647     LineSectionSize += Offset - OffsetBeforeLEBs;
 648   }
 649   Asm->emitInt8(0);
 650   LineSectionSize += 1;
 651
 652   Asm->OutStreamer->EmitLabel(HeaderEndLabel);
 653
 654   // Copy the actual line table program over.
 655   Asm->OutStreamer->EmitBytes(Contents.slice(Offset, UnitEnd));
 656   LineSectionSize += UnitEnd - Offset;
 657
 658   Asm->OutStreamer->EmitLabel(EndLabel);
 659   Offset = UnitEnd;
 660 }
 661
 662 static void emitSectionContents(const object::ObjectFile &Obj,
 663                                 StringRef SecName, MCStreamer *MS) {
 664   StringRef Contents;
 665   if (auto Sec = getSectionByName(Obj, SecName))
 666     if (!Sec->getContents(Contents))
 667       MS->EmitBytes(Contents);
 668 }
 669
 670 void DwarfStreamer::copyInvariantDebugSection(const object::ObjectFile &Obj) {
 671   if (!Options.Translator) {
 672     MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLineSection());
 673     emitSectionContents(Obj, "debug_line", MS);
 674   }
 675
 676   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLocSection());
 677   emitSectionContents(Obj, "debug_loc", MS);
 678
 679   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfRangesSection());
 680   emitSectionContents(Obj, "debug_ranges", MS);
 681
 682   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfFrameSection());
 683   emitSectionContents(Obj, "debug_frame", MS);
 684
 685   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfARangesSection());
 686   emitSectionContents(Obj, "debug_aranges", MS);
 687 }
 688
 689 /// Emit the pubnames or pubtypes section contribution for \p
 690 /// Unit into \p Sec. The data is provided in \p Names.
 691 void DwarfStreamer::emitPubSectionForUnit(
 692     MCSection *Sec, StringRef SecName, const CompileUnit &Unit,
 693     const std::vector<CompileUnit::AccelInfo> &Names) {
 694   if (Names.empty())
 695     return;
 696
 697   // Start the dwarf pubnames section.
 698   Asm->OutStreamer->SwitchSection(Sec);
 699   MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + SecName + "_begin");
 700   MCSymbol *EndLabel = Asm->createTempSymbol("pub" + SecName + "_end");
 701
 702   bool HeaderEmitted = false;
 703   // Emit the pubnames for this compilation unit.
 704   for (const auto &Name : Names) {
 705     if (Name.SkipPubSection)
 706       continue;
 707
 708     if (!HeaderEmitted) {
 709       // Emit the header.
 710       Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); // Length
 711       Asm->OutStreamer->EmitLabel(BeginLabel);
 712       Asm->emitInt16(dwarf::DW_PUBNAMES_VERSION); // Version
 713       Asm->emitInt32(Unit.getStartOffset());      // Unit offset
 714       Asm->emitInt32(Unit.getNextUnitOffset() - Unit.getStartOffset()); // Size
 715       HeaderEmitted = true;
 716     }
 717     Asm->emitInt32(Name.Die->getOffset());
 718
 719     // Emit the string itself.
 720     Asm->OutStreamer->EmitBytes(Name.Name.getString());
 721     // Emit a null terminator.
 722     Asm->emitInt8(0);
 723   }
 724
 725   if (!HeaderEmitted)
 726     return;
 727   Asm->emitInt32(0); // End marker.
 728   Asm->OutStreamer->EmitLabel(EndLabel);
 729 }
 730
 731 /// Emit .debug_pubnames for \p Unit.
 732 void DwarfStreamer::emitPubNamesForUnit(const CompileUnit &Unit) {
 733   emitPubSectionForUnit(MC->getObjectFileInfo()->getDwarfPubNamesSection(),
 734                         "names", Unit, Unit.getPubnames());
 735 }
 736
 737 /// Emit .debug_pubtypes for \p Unit.
 738 void DwarfStreamer::emitPubTypesForUnit(const CompileUnit &Unit) {
 739   emitPubSectionForUnit(MC->getObjectFileInfo()->getDwarfPubTypesSection(),
 740                         "types", Unit, Unit.getPubtypes());
 741 }
 742
 743 /// Emit a CIE into the debug_frame section.
 744 void DwarfStreamer::emitCIE(StringRef CIEBytes) {
 745   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfFrameSection());
 746
 747   MS->EmitBytes(CIEBytes);
 748   FrameSectionSize += CIEBytes.size();
 749 }
 750
 751 /// Emit a FDE into the debug_frame section. \p FDEBytes
 752 /// contains the FDE data without the length, CIE offset and address
 753 /// which will be replaced with the parameter values.
 754 void DwarfStreamer::emitFDE(uint32_t CIEOffset, uint32_t AddrSize,
 755                             uint32_t Address, StringRef FDEBytes) {
 756   MS->SwitchSection(MC->getObjectFileInfo()->getDwarfFrameSection());
 757
 758   MS->EmitIntValue(FDEBytes.size() + 4 + AddrSize, 4);
 759   MS->EmitIntValue(CIEOffset, 4);
 760   MS->EmitIntValue(Address, AddrSize);
 761   MS->EmitBytes(FDEBytes);
 762   FrameSectionSize += FDEBytes.size() + 8 + AddrSize;
 763 }
 764
 765 } // namespace dsymutil
 766 } // namespace llvm