C++ DWARFContext类代码示例

static bool isVariableIndexable(const DWARFDie &Die, DWARFContext &DCtx) {
  Optional<DWARFFormValue> Location = Die.findRecursively(DW_AT_location);
  if (!Location)
    return false;

  auto ContainsInterestingOperators = [&](StringRef D) {
    DWARFUnit *U = Die.getDwarfUnit();
    DataExtractor Data(D, DCtx.isLittleEndian(), U->getAddressByteSize());
    DWARFExpression Expression(Data, U->getVersion(), U->getAddressByteSize());
    return any_of(Expression, [](DWARFExpression::Operation &Op) {
      return !Op.isError() && (Op.getCode() == DW_OP_addr ||
                               Op.getCode() == DW_OP_form_tls_address ||
                               Op.getCode() == DW_OP_GNU_push_tls_address);
    });
  };

  if (Optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
    // Inlined location.
    if (ContainsInterestingOperators(toStringRef(*Expr)))
      return true;
  } else if (Optional<uint64_t> Offset = Location->getAsSectionOffset()) {
    // Location list.
    if (const DWARFDebugLoc *DebugLoc = DCtx.getDebugLoc()) {
      if (const DWARFDebugLoc::LocationList *LocList =
              DebugLoc->getLocationListAtOffset(*Offset)) {
        if (any_of(LocList->Entries, [&](const DWARFDebugLoc::Entry &E) {
              return ContainsInterestingOperators({E.Loc.data(), E.Loc.size()});
            }))
          return true;
      }
    }
  }
  return false;
}

void DWARFUnitSectionBase::parse(DWARFContext &C, const DWARFSection &Section) {
  const DWARFObject &D = C.getDWARFObj();
  parseImpl(C, Section, C.getDebugAbbrev(), &D.getRangeSection(),
            D.getStringSection(), D.getStringOffsetSection(),
            &D.getAddrSection(), D.getLineSection(), D.isLittleEndian(), false,
            false);
}

static bool dumpObjectFile(ObjectFile &Obj, DWARFContext &DICtx, Twine Filename,
                           raw_ostream &OS) {
  logAllUnhandledErrors(DICtx.loadRegisterInfo(Obj), errs(),
                        Filename.str() + ": ");
  // The UUID dump already contains all the same information.
  if (!(DumpType & DIDT_UUID) || DumpType == DIDT_All)
    OS << Filename << ":\tfile format " << Obj.getFileFormatName() << '\n';

  // Handle the --lookup option.
  if (Lookup)
    return lookup(DICtx, Lookup, OS);

  // Handle the --name option.
  if (!Name.empty()) {
    StringSet<> Names;
    for (auto name : Name)
      Names.insert((IgnoreCase && !UseRegex) ? StringRef(name).lower() : name);

    filterByName(Names, DICtx.compile_units(), OS);
    filterByName(Names, DICtx.dwo_compile_units(), OS);
    return true;
  }

  // Handle the --find option and lower it to --debug-info=<offset>.
  if (!Find.empty()) {
    filterByAccelName(Find, DICtx, OS);
    return true;
  }

  // Dump the complete DWARF structure.
  DICtx.dump(OS, getDumpOpts(), DumpOffsets);
  return true;
}

void DWARFUnitSectionBase::parseDWO(DWARFContext &C,
                                    const DWARFSection &DWOSection, bool Lazy) {
  const DWARFObject &D = C.getDWARFObj();
  parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), &D.getRangeDWOSection(),
            D.getStringDWOSection(), D.getStringOffsetDWOSection(),
            &D.getAddrSection(), D.getLineDWOSection(), C.isLittleEndian(),
            true, Lazy);
}

void DWARFUnitVector::addUnitsForSection(DWARFContext &C,
                                         const DWARFSection &Section,
                                         DWARFSectionKind SectionKind) {
  const DWARFObject &D = C.getDWARFObj();
  addUnitsImpl(C, D, Section, C.getDebugAbbrev(), &D.getRangeSection(),
               D.getStringSection(), D.getStringOffsetSection(),
               &D.getAddrSection(), D.getLineSection(), D.isLittleEndian(),
               false, false, SectionKind);
}

void DWARFUnitVector::addUnitsForDWOSection(DWARFContext &C,
                                            const DWARFSection &DWOSection,
                                            DWARFSectionKind SectionKind,
                                            bool Lazy) {
  const DWARFObject &D = C.getDWARFObj();
  addUnitsImpl(C, D, DWOSection, C.getDebugAbbrevDWO(), &D.getRangeDWOSection(),
               D.getStringDWOSection(), D.getStringOffsetDWOSection(),
               &D.getAddrSection(), D.getLineDWOSection(), C.isLittleEndian(),
               true, Lazy, SectionKind);
}

/// Print only DIEs that have a certain name.
static void filterByAccelName(ArrayRef<std::string> Names, DWARFContext &DICtx,
                              raw_ostream &OS) {
  SmallVector<uint64_t, 4> Offsets;
  for (const auto &Name : Names) {
    getDIEOffset(DICtx.getAppleNames(), Name, Offsets);
    getDIEOffset(DICtx.getAppleTypes(), Name, Offsets);
    getDIEOffset(DICtx.getAppleNamespaces(), Name, Offsets);
    getDIEOffset(DICtx.getDebugNames(), Name, Offsets);
  }
  llvm::sort(Offsets.begin(), Offsets.end());
  Offsets.erase(std::unique(Offsets.begin(), Offsets.end()), Offsets.end());

  for (uint64_t Off: Offsets) {
    DWARFDie Die = DICtx.getDIEForOffset(Off);
    Die.dump(OS, 0, getDumpOpts());
  }
}

void DWARFUnitSectionBase::parseDWO(DWARFContext &C,
                                    const DWARFSection &DWOSection,
                                    DWARFUnitIndex *Index) {
  parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), C.getRangeDWOSection(),
            C.getStringDWOSection(), C.getStringOffsetDWOSection(),
            C.getAddrSection(), C.getLineDWOSection().Data, C.isLittleEndian());
}

/// Emit location lists for \p Unit and update attributes to point to the new
/// entries.
void DwarfStreamer::emitLocationsForUnit(const CompileUnit &Unit,
                                         DWARFContext &Dwarf) {
  const auto &Attributes = Unit.getLocationAttributes();

  if (Attributes.empty())
    return;

  MS->SwitchSection(MC->getObjectFileInfo()->getDwarfLocSection());

  unsigned AddressSize = Unit.getOrigUnit().getAddressByteSize();
  const DWARFSection &InputSec = Dwarf.getDWARFObj().getLocSection();
  DataExtractor Data(InputSec.Data, Dwarf.isLittleEndian(), AddressSize);
  DWARFUnit &OrigUnit = Unit.getOrigUnit();
  auto OrigUnitDie = OrigUnit.getUnitDIE(false);
  int64_t UnitPcOffset = 0;
  if (auto OrigLowPc = dwarf::toAddress(OrigUnitDie.find(dwarf::DW_AT_low_pc)))
    UnitPcOffset = int64_t(*OrigLowPc) - Unit.getLowPc();

  for (const auto &Attr : Attributes) {
    uint32_t Offset = Attr.first.get();
    Attr.first.set(LocSectionSize);
    // This is the quantity to add to the old location address to get
    // the correct address for the new one.
    int64_t LocPcOffset = Attr.second + UnitPcOffset;
    while (Data.isValidOffset(Offset)) {
      uint64_t Low = Data.getUnsigned(&Offset, AddressSize);
      uint64_t High = Data.getUnsigned(&Offset, AddressSize);
      LocSectionSize += 2 * AddressSize;
      if (Low == 0 && High == 0) {
        Asm->OutStreamer->EmitIntValue(0, AddressSize);
        Asm->OutStreamer->EmitIntValue(0, AddressSize);
        break;
      }
      Asm->OutStreamer->EmitIntValue(Low + LocPcOffset, AddressSize);
      Asm->OutStreamer->EmitIntValue(High + LocPcOffset, AddressSize);
      uint64_t Length = Data.getU16(&Offset);
      Asm->OutStreamer->EmitIntValue(Length, 2);
      // Just copy the bytes over.
      Asm->OutStreamer->EmitBytes(
          StringRef(InputSec.Data.substr(Offset, Length)));
      Offset += Length;
      LocSectionSize += Length + 2;
    }
  }
}

/// Handle the --lookup option and dump the DIEs and line info for the given
/// address.
static bool lookup(DWARFContext &DICtx, uint64_t Address, raw_ostream &OS) {
  auto DIEsForAddr = DICtx.getDIEsForAddress(Lookup);

  if (!DIEsForAddr)
    return false;

  DIDumpOptions DumpOpts = getDumpOpts();
  DumpOpts.RecurseDepth = 0;
  DIEsForAddr.CompileUnit->dump(OS, DumpOpts);
  if (DIEsForAddr.FunctionDIE) {
    DIEsForAddr.FunctionDIE.dump(OS, 2, DumpOpts);
    if (DIEsForAddr.BlockDIE)
      DIEsForAddr.BlockDIE.dump(OS, 4, DumpOpts);
  }

  if (DILineInfo LineInfo = DICtx.getLineInfoForAddress(Lookup))
    LineInfo.dump(OS);

  return true;
}

static bool dumpObjectFile(ObjectFile &Obj, DWARFContext &DICtx, Twine Filename,
                           raw_ostream &OS) {
  logAllUnhandledErrors(DICtx.loadRegisterInfo(Obj), errs(),
                        Filename.str() + ": ");
  // The UUID dump already contains all the same information.
  if (!(DumpType & DIDT_UUID) || DumpType == DIDT_All)
    OS << Filename << ":\tfile format " << Obj.getFileFormatName() << '\n';

  // Handle the --lookup option.
  if (Lookup)
    return lookup(DICtx, Lookup, OS);

  // Handle the --name option.
  if (!Name.empty()) {
    StringSet<> Names;
    for (auto name : Name)
      Names.insert((IgnoreCase && !UseRegex) ? StringRef(name).lower() : name);

    filterByName(Names, DICtx.compile_units(), OS);
    filterByName(Names, DICtx.dwo_compile_units(), OS);
    return true;
  }

  // Handle the --find option and lower it to --debug-info=<offset>.
  if (!Find.empty()) {
    DumpOffsets[DIDT_ID_DebugInfo] = [&]() -> llvm::Optional<uint64_t> {
      for (auto Name : Find) {
        auto find = [&](const DWARFAcceleratorTable &Accel)
            -> llvm::Optional<uint64_t> {
          for (auto Entry : Accel.equal_range(Name))
            for (auto Atom : Entry)
              if (auto Offset = Atom.getAsSectionOffset())
                return Offset;
          return None;
        };
        if (auto Offset = find(DICtx.getAppleNames()))
          return DumpOffsets[DIDT_ID_DebugInfo] = *Offset;
        if (auto Offset = find(DICtx.getAppleTypes()))
          return DumpOffsets[DIDT_ID_DebugInfo] = *Offset;
        if (auto Offset = find(DICtx.getAppleNamespaces()))
          return DumpOffsets[DIDT_ID_DebugInfo] = *Offset;
      }
      return None;
    }();
    // Early exit if --find was specified but the current file doesn't have it.
    if (!DumpOffsets[DIDT_ID_DebugInfo])
      return true;
  }

  // Dump the complete DWARF structure.
  DICtx.dump(OS, getDumpOpts(), DumpOffsets);
  return true;
}

static bool verifyObjectFile(ObjectFile &Obj, DWARFContext &DICtx,
                             Twine Filename, raw_ostream &OS) {
  // Verify the DWARF and exit with non-zero exit status if verification
  // fails.
  raw_ostream &stream = Quiet ? nulls() : OS;
  stream << "Verifying " << Filename.str() << ":\tfile format "
  << Obj.getFileFormatName() << "\n";
  bool Result = DICtx.verify(stream, getDumpOpts());
  if (Result)
    stream << "No errors.\n";
  else
    stream << "Errors detected.\n";
  return Result;
}

void DWARFUnitSectionBase::parse(DWARFContext &C, const DWARFSection &Section) {
  parseImpl(C, Section, C.getDebugAbbrev(), C.getRangeSection(),
            C.getStringSection(), StringRef(), C.getAddrSection(),
            C.isLittleEndian());
}

bool DWARFUnitHeader::extract(DWARFContext &Context,
                              const DWARFDataExtractor &debug_info,
                              uint32_t *offset_ptr,
                              DWARFSectionKind SectionKind,
                              const DWARFUnitIndex *Index) {
  Offset = *offset_ptr;
  IndexEntry = Index ? Index->getFromOffset(*offset_ptr) : nullptr;
  Length = debug_info.getU32(offset_ptr);
  // FIXME: Support DWARF64.
  unsigned SizeOfLength = 4;
  FormParams.Format = DWARF32;
  FormParams.Version = debug_info.getU16(offset_ptr);
  if (FormParams.Version >= 5) {
    UnitType = debug_info.getU8(offset_ptr);
    FormParams.AddrSize = debug_info.getU8(offset_ptr);
    AbbrOffset = debug_info.getU32(offset_ptr);
  } else {
    AbbrOffset = debug_info.getRelocatedValue(4, offset_ptr);
    FormParams.AddrSize = debug_info.getU8(offset_ptr);
    // Fake a unit type based on the section type.  This isn't perfect,
    // but distinguishing compile and type units is generally enough.
    if (SectionKind == DW_SECT_TYPES)
      UnitType = DW_UT_type;
    else
      UnitType = DW_UT_compile;
  }
  if (IndexEntry) {
    if (AbbrOffset)
      return false;
    auto *UnitContrib = IndexEntry->getOffset();
    if (!UnitContrib || UnitContrib->Length != (Length + 4))
      return false;
    auto *AbbrEntry = IndexEntry->getOffset(DW_SECT_ABBREV);
    if (!AbbrEntry)
      return false;
    AbbrOffset = AbbrEntry->Offset;
  }
  if (isTypeUnit()) {
    TypeHash = debug_info.getU64(offset_ptr);
    TypeOffset = debug_info.getU32(offset_ptr);
  } else if (UnitType == DW_UT_split_compile || UnitType == DW_UT_skeleton)
    DWOId = debug_info.getU64(offset_ptr);

  // Header fields all parsed, capture the size of this unit header.
  assert(*offset_ptr - Offset <= 255 && "unexpected header size");
  Size = uint8_t(*offset_ptr - Offset);

  // Type offset is unit-relative; should be after the header and before
  // the end of the current unit.
  bool TypeOffsetOK =
      !isTypeUnit()
          ? true
          : TypeOffset >= Size && TypeOffset < getLength() + SizeOfLength;
  bool LengthOK = debug_info.isValidOffset(getNextUnitOffset() - 1);
  bool VersionOK = DWARFContext::isSupportedVersion(getVersion());
  bool AddrSizeOK = getAddressByteSize() == 4 || getAddressByteSize() == 8;

  if (!LengthOK || !VersionOK || !AddrSizeOK || !TypeOffsetOK)
    return false;

  // Keep track of the highest DWARF version we encounter across all units.
  Context.setMaxVersionIfGreater(getVersion());
  return true;
}