C++ DWARFDataExtractor::isValidOffset方法代码示例

void DWARFDebugLoc::parse(const DWARFDataExtractor &data) {
  IsLittleEndian = data.isLittleEndian();
  AddressSize = data.getAddressSize();

  uint32_t Offset = 0;
  while (data.isValidOffset(Offset + data.getAddressSize() - 1)) {
    if (auto LL = parseOneLocationList(data, &Offset))
      Locations.push_back(std::move(*LL));
    else
      break;
  }
  if (data.isValidOffset(Offset))
    errs() << "error: failed to consume entire .debug_loc section\n";
}

llvm::Error DWARFDebugNames::Header::extract(const DWARFDataExtractor &AS,
                                             uint32_t *Offset) {
  // Check that we can read the fixed-size part.
  if (!AS.isValidOffset(*Offset + sizeof(HeaderPOD) - 1))
    return make_error<StringError>("Section too small: cannot read header.",
                                   inconvertibleErrorCode());

  UnitLength = AS.getU32(Offset);
  Version = AS.getU16(Offset);
  Padding = AS.getU16(Offset);
  CompUnitCount = AS.getU32(Offset);
  LocalTypeUnitCount = AS.getU32(Offset);
  ForeignTypeUnitCount = AS.getU32(Offset);
  BucketCount = AS.getU32(Offset);
  NameCount = AS.getU32(Offset);
  AbbrevTableSize = AS.getU32(Offset);
  AugmentationStringSize = AS.getU32(Offset);

  if (!AS.isValidOffsetForDataOfSize(*Offset, AugmentationStringSize))
    return make_error<StringError>(
        "Section too small: cannot read header augmentation.",
        inconvertibleErrorCode());
  AugmentationString.resize(AugmentationStringSize);
  AS.getU8(Offset, reinterpret_cast<uint8_t *>(AugmentationString.data()),
           AugmentationStringSize);
  *Offset = alignTo(*Offset, 4);
  return Error::success();
}

bool DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
                                  uint32_t *offset_ptr) {
  clear();
  if (!data.isValidOffset(*offset_ptr))
    return false;
  AddressSize = data.getAddressSize();
  if (AddressSize != 4 && AddressSize != 8)
    return false;
  Offset = *offset_ptr;
  while (true) {
    RangeListEntry entry;
    uint32_t prev_offset = *offset_ptr;
    entry.StartAddress =
        data.getRelocatedAddress(offset_ptr, &entry.SectionIndex);
    entry.EndAddress = data.getRelocatedAddress(offset_ptr);

    // Check that both values were extracted correctly.
    if (*offset_ptr != prev_offset + 2 * AddressSize) {
      clear();
      return false;
    }
    if (entry.isEndOfListEntry())
      break;
    Entries.push_back(entry);
  }
  return true;
}

Error DWARFDebugRangeList::extract(const DWARFDataExtractor &data,
                                   uint32_t *offset_ptr) {
  clear();
  if (!data.isValidOffset(*offset_ptr))
    return createStringError(errc::invalid_argument,
                       "invalid range list offset 0x%" PRIx32, *offset_ptr);

  AddressSize = data.getAddressSize();
  if (AddressSize != 4 && AddressSize != 8)
    return createStringError(errc::invalid_argument,
                       "invalid address size: %" PRIu8, AddressSize);
  Offset = *offset_ptr;
  while (true) {
    RangeListEntry Entry;
    Entry.SectionIndex = -1ULL;

    uint32_t prev_offset = *offset_ptr;
    Entry.StartAddress = data.getRelocatedAddress(offset_ptr);
    Entry.EndAddress =
        data.getRelocatedAddress(offset_ptr, &Entry.SectionIndex);

    // Check that both values were extracted correctly.
    if (*offset_ptr != prev_offset + 2 * AddressSize) {
      clear();
      return createStringError(errc::invalid_argument,
                         "invalid range list entry at offset 0x%" PRIx32,
                         prev_offset);
    }
    if (Entry.isEndOfListEntry())
      break;
    Entries.push_back(Entry);
  }
  return Error::success();
}

Expected<const DWARFDebugLine::LineTable *> DWARFDebugLine::getOrParseLineTable(
    DWARFDataExtractor &DebugLineData, uint32_t Offset, const DWARFContext &Ctx,
    const DWARFUnit *U, std::function<void(Error)> RecoverableErrorCallback) {
  if (!DebugLineData.isValidOffset(Offset))
    return createStringError(errc::invalid_argument, "offset 0x%8.8" PRIx32
                       " is not a valid debug line section offset",
                       Offset);

  std::pair<LineTableIter, bool> Pos =
      LineTableMap.insert(LineTableMapTy::value_type(Offset, LineTable()));
  LineTable *LT = &Pos.first->second;
  if (Pos.second) {
    if (Error Err =
            LT->parse(DebugLineData, &Offset, Ctx, U, RecoverableErrorCallback))
      return std::move(Err);
    return LT;
  }
  return LT;
}

bool DWARFVerifier::verifyUnitHeader(const DWARFDataExtractor DebugInfoData,
                                     uint32_t *Offset, unsigned UnitIndex,
                                     uint8_t &UnitType, bool &isUnitDWARF64) {
  uint32_t AbbrOffset, Length;
  uint8_t AddrSize = 0;
  uint16_t Version;
  bool Success = true;

  bool ValidLength = false;
  bool ValidVersion = false;
  bool ValidAddrSize = false;
  bool ValidType = true;
  bool ValidAbbrevOffset = true;

  uint32_t OffsetStart = *Offset;
  Length = DebugInfoData.getU32(Offset);
  if (Length == UINT32_MAX) {
    isUnitDWARF64 = true;
    OS << format(
        "Unit[%d] is in 64-bit DWARF format; cannot verify from this point.\n",
        UnitIndex);
    return false;
  }
  Version = DebugInfoData.getU16(Offset);

  if (Version >= 5) {
    UnitType = DebugInfoData.getU8(Offset);
    AddrSize = DebugInfoData.getU8(Offset);
    AbbrOffset = DebugInfoData.getU32(Offset);
    ValidType = dwarf::isUnitType(UnitType);
  } else {
    UnitType = 0;
    AbbrOffset = DebugInfoData.getU32(Offset);
    AddrSize = DebugInfoData.getU8(Offset);
  }

  if (!DCtx.getDebugAbbrev()->getAbbreviationDeclarationSet(AbbrOffset))
    ValidAbbrevOffset = false;

  ValidLength = DebugInfoData.isValidOffset(OffsetStart + Length + 3);
  ValidVersion = DWARFContext::isSupportedVersion(Version);
  ValidAddrSize = AddrSize == 4 || AddrSize == 8;
  if (!ValidLength || !ValidVersion || !ValidAddrSize || !ValidAbbrevOffset ||
      !ValidType) {
    Success = false;
    error() << format("Units[%d] - start offset: 0x%08x \n", UnitIndex,
                      OffsetStart);
    if (!ValidLength)
      note() << "The length for this unit is too "
            "large for the .debug_info provided.\n";
    if (!ValidVersion)
      note() << "The 16 bit unit header version is not valid.\n";
    if (!ValidType)
      note() << "The unit type encoding is not valid.\n";
    if (!ValidAbbrevOffset)
      note() << "The offset into the .debug_abbrev section is "
            "not valid.\n";
    if (!ValidAddrSize)
      note() << "The address size is unsupported.\n";
  }
  *Offset = OffsetStart + Length + 4;
  return Success;
}

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;
}