C++ DWARFDataExtractor类代码示例

void
SymbolFileDWARFDwo::LoadSectionData (lldb::SectionType sect_type, DWARFDataExtractor& data)
{
    const SectionList* section_list = m_obj_file->GetSectionList(false /* update_module_section_list */);
    if (section_list)
    {
        SectionSP section_sp (section_list->FindSectionByType(sect_type, true));
        if (section_sp)
        {
            // See if we memory mapped the DWARF segment?
            if (m_dwarf_data.GetByteSize())
            {
                data.SetData(m_dwarf_data, section_sp->GetOffset(), section_sp->GetFileSize());
                return;
            }

            if (m_obj_file->ReadSectionData(section_sp.get(), data) != 0)
                return;

            data.Clear();
        }
    }

    SymbolFileDWARF::LoadSectionData(sect_type, data);
}

bool
DWARFAbbreviationDeclaration::Extract(const DWARFDataExtractor& data, lldb::offset_t *offset_ptr, dw_uleb128_t code)
{
    m_code = code;
    m_attributes.clear();
    if (m_code)
    {
        m_tag = data.GetULEB128(offset_ptr);
        m_has_children = data.GetU8(offset_ptr);

        while (data.ValidOffset(*offset_ptr))
        {
            dw_attr_t attr = data.GetULEB128(offset_ptr);
            dw_form_t form = data.GetULEB128(offset_ptr);

            if (attr && form)
                m_attributes.push_back(DWARFAttribute(attr, form));
            else
                break;
        }

        return m_tag != 0;
    }
    else
    {
        m_tag = 0;
        m_has_children = 0;
    }

    return false;
}

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();
}

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;
}

// Parse v2-v4 directory and file tables.
static void
parseV2DirFileTables(const DWARFDataExtractor &DebugLineData,
                     uint32_t *OffsetPtr, uint64_t EndPrologueOffset,
                     DWARFDebugLine::ContentTypeTracker &ContentTypes,
                     std::vector<DWARFFormValue> &IncludeDirectories,
                     std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
  while (*OffsetPtr < EndPrologueOffset) {
    StringRef S = DebugLineData.getCStrRef(OffsetPtr);
    if (S.empty())
      break;
    DWARFFormValue Dir =
        DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, S.data());
    IncludeDirectories.push_back(Dir);
  }

  while (*OffsetPtr < EndPrologueOffset) {
    StringRef Name = DebugLineData.getCStrRef(OffsetPtr);
    if (Name.empty())
      break;
    DWARFDebugLine::FileNameEntry FileEntry;
    FileEntry.Name =
        DWARFFormValue::createFromPValue(dwarf::DW_FORM_string, Name.data());
    FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr);
    FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr);
    FileEntry.Length = DebugLineData.getULEB128(OffsetPtr);
    FileNames.push_back(FileEntry);
  }

  ContentTypes.HasModTime = true;
  ContentTypes.HasLength = true;
}

bool
DWARFDebugPubnames::Extract(const DWARFDataExtractor& data)
{
    Timer scoped_timer (__PRETTY_FUNCTION__,
                        "DWARFDebugPubnames::Extract (byte_size = %" PRIu64 ")",
                        (uint64_t)data.GetByteSize());
    Log *log (LogChannelDWARF::GetLogIfAll(DWARF_LOG_DEBUG_PUBNAMES));
    if (log)
        log->Printf("DWARFDebugPubnames::Extract (byte_size = %" PRIu64 ")", (uint64_t)data.GetByteSize());

    if (data.ValidOffset(0))
    {
        lldb::offset_t offset = 0;

        DWARFDebugPubnamesSet set;
        while (data.ValidOffset(offset))
        {
            if (set.Extract(data, &offset))
            {
                m_sets.push_back(set);
                offset = set.GetOffsetOfNextEntry();
            }
            else
                break;
        }
        if (log)
            Dump (log);
        return true;
    }
    return false;
}

bool DWARFTypeUnit::extractImpl(const DWARFDataExtractor &debug_info,
                                uint32_t *offset_ptr) {
  if (!DWARFUnit::extractImpl(debug_info, offset_ptr))
    return false;
  TypeHash = debug_info.getU64(offset_ptr);
  TypeOffset = debug_info.getU32(offset_ptr);
  // TypeOffset is relative to the beginning of the header,
  // so we have to account for the leading length field.
  // FIXME: The size of the length field is 12 in DWARF64.
  unsigned SizeOfLength = 4;
  return TypeOffset < getLength() + SizeOfLength;
}

// Look for a DWARF32-formatted contribution to the string offsets table
// starting at a given offset and record it in a descriptor.
static Optional<StrOffsetsContributionDescriptor>
parseDWARF32StringOffsetsTableHeader(DWARFDataExtractor &DA, uint32_t Offset) {
  if (!DA.isValidOffsetForDataOfSize(Offset, 8))
    return None;
  uint32_t ContributionSize = DA.getU32(&Offset);
  if (ContributionSize >= 0xfffffff0)
    return None;
  uint8_t Version = DA.getU16(&Offset);
  (void)DA.getU16(&Offset); // padding
  // The encoded length includes the 2-byte version field and the 2-byte
  // padding, so we need to subtract them out when we populate the descriptor.
  return {{Offset, ContributionSize - 4, Version, DWARF32}};
}

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";
}

void DWARFDebugMacroHeader::SkipOperandTable(
    const DWARFDataExtractor &debug_macro_data, lldb::offset_t *offset) {
  uint8_t entry_count = debug_macro_data.GetU8(offset);
  for (uint8_t i = 0; i < entry_count; i++) {
    // Skip over the opcode number.
    debug_macro_data.GetU8(offset);

    uint64_t operand_count = debug_macro_data.GetULEB128(offset);

    for (uint64_t j = 0; j < operand_count; j++) {
      // Skip over the operand form
      debug_macro_data.GetU8(offset);
    }
  }
}

// Look for a DWARF64-formatted contribution to the string offsets table
// starting at a given offset and record it in a descriptor.
static Optional<StrOffsetsContributionDescriptor>
parseDWARF64StringOffsetsTableHeader(DWARFDataExtractor &DA, uint32_t Offset) {
  if (!DA.isValidOffsetForDataOfSize(Offset, 16))
    return Optional<StrOffsetsContributionDescriptor>();

  if (DA.getU32(&Offset) != 0xffffffff)
    return Optional<StrOffsetsContributionDescriptor>();

  uint64_t Size = DA.getU64(&Offset);
  uint8_t Version = DA.getU16(&Offset);
  (void)DA.getU16(&Offset); // padding
  // The encoded length includes the 2-byte version field and the 2-byte
  // padding, so we need to subtract them out when we populate the descriptor.
  return StrOffsetsContributionDescriptor(Offset, Size - 4, Version, DWARF64);
  //return Optional<StrOffsetsContributionDescriptor>(Descriptor);
}

bool
DWARFCompileUnit::Extract(const DWARFDataExtractor &debug_info, lldb::offset_t *offset_ptr)
{
    Clear();

    m_offset = *offset_ptr;

    if (debug_info.ValidOffset(*offset_ptr))
    {
        dw_offset_t abbr_offset;
        const DWARFDebugAbbrev *abbr = m_dwarf2Data->DebugAbbrev();
        m_length        = debug_info.GetDWARFInitialLength(offset_ptr);
        m_is_dwarf64    = debug_info.IsDWARF64();
        m_version       = debug_info.GetU16(offset_ptr);
        abbr_offset     = debug_info.GetDWARFOffset(offset_ptr);
        m_addr_size     = debug_info.GetU8 (offset_ptr);

        bool length_OK = debug_info.ValidOffset(GetNextCompileUnitOffset()-1);
        bool version_OK = SymbolFileDWARF::SupportedVersion(m_version);
        bool abbr_offset_OK = m_dwarf2Data->get_debug_abbrev_data().ValidOffset(abbr_offset);
        bool addr_size_OK = ((m_addr_size == 4) || (m_addr_size == 8));

        if (length_OK && version_OK && addr_size_OK && abbr_offset_OK && abbr != NULL)
        {
            m_abbrevs = abbr->GetAbbreviationDeclarationSet(abbr_offset);
            return true;
        }

        // reset the offset to where we tried to parse from if anything went wrong
        *offset_ptr = m_offset;
    }

    return false;
}

// Parse v5 directory/file entry content descriptions.
// Returns the descriptors, or an empty vector if we did not find a path or
// ran off the end of the prologue.
static ContentDescriptors
parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
                   uint64_t EndPrologueOffset, bool *HasMD5) {
  ContentDescriptors Descriptors;
  int FormatCount = DebugLineData.getU8(OffsetPtr);
  bool HasPath = false;
  for (int I = 0; I != FormatCount; ++I) {
    if (*OffsetPtr >= EndPrologueOffset)
      return ContentDescriptors();
    ContentDescriptor Descriptor;
    Descriptor.Type =
      dwarf::LineNumberEntryFormat(DebugLineData.getULEB128(OffsetPtr));
    Descriptor.Form = dwarf::Form(DebugLineData.getULEB128(OffsetPtr));
    if (Descriptor.Type == dwarf::DW_LNCT_path)
      HasPath = true;
    else if (Descriptor.Type == dwarf::DW_LNCT_MD5 && HasMD5)
      *HasMD5 = true;
    Descriptors.push_back(Descriptor);
  }
  return HasPath ? Descriptors : ContentDescriptors();
}

Optional<StrOffsetsContributionDescriptor>
StrOffsetsContributionDescriptor::validateContributionSize(
    DWARFDataExtractor &DA) {
  uint8_t EntrySize = getDwarfOffsetByteSize();
  // In order to ensure that we don't read a partial record at the end of
  // the section we validate for a multiple of the entry size.
  uint64_t ValidationSize = alignTo(Size, EntrySize);
  // Guard against overflow.
  if (ValidationSize >= Size)
    if (DA.isValidOffsetForDataOfSize((uint32_t)Base, ValidationSize))
      return *this;
  return Optional<StrOffsetsContributionDescriptor>();
}

//----------------------------------------------------------------------
// DWARFDebugAbbrev::Parse()
//----------------------------------------------------------------------
void DWARFDebugAbbrev::Parse(const DWARFDataExtractor &data) {
  lldb::offset_t offset = 0;

  while (data.ValidOffset(offset)) {
    uint32_t initial_cu_offset = offset;
    DWARFAbbreviationDeclarationSet abbrevDeclSet;

    if (abbrevDeclSet.Extract(data, &offset))
      m_abbrevCollMap[initial_cu_offset] = abbrevDeclSet;
    else
      break;
  }
  m_prev_abbr_offset_pos = m_abbrevCollMap.end();
}