C++ DataExtractor类代码示例

static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data,
        uint32_t Offset, int Length) {
    errs() << "DUMP: ";
    for (int i = 0; i < Length; ++i) {
        uint8_t c = Data.getU8(&Offset);
        errs().write_hex(c);
        errs() << " ";
    }
    errs() << "\n";
}

bool
Type::ReadFromMemory (ExecutionContext *exe_ctx, lldb::addr_t addr, AddressType address_type, DataExtractor &data)
{
    if (address_type == eAddressTypeFile)
    {
        // Can't convert a file address to anything valid without more
        // context (which Module it came from)
        return false;
    }

    const uint64_t byte_size = GetByteSize();
    if (data.GetByteSize() < byte_size)
    {
        lldb::DataBufferSP data_sp(new DataBufferHeap (byte_size, '\0'));
        data.SetData(data_sp);
    }

    uint8_t* dst = (uint8_t*)data.PeekData(0, byte_size);
    if (dst != nullptr)
    {
        if (address_type == eAddressTypeHost)
        {
            // The address is an address in this process, so just copy it
            if (addr == 0)
                return false;
            memcpy (dst, (uint8_t*)nullptr + addr, byte_size);
            return true;
        }
        else
        {
            if (exe_ctx)
            {
                Process *process = exe_ctx->GetProcessPtr();
                if (process)
                {
                    Error error;
                    return exe_ctx->GetProcessPtr()->ReadMemory(addr, dst, byte_size, error) == byte_size;
                }
            }
        }
    }
    return false;
}

bool DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
  Length = debug_info.getU32(offset_ptr);
  Version = debug_info.getU16(offset_ptr);
  uint64_t AbbrOffset = debug_info.getU32(offset_ptr);
  AddrSize = debug_info.getU8(offset_ptr);

  bool LengthOK = debug_info.isValidOffset(getNextUnitOffset() - 1);
  bool VersionOK = DWARFContext::isSupportedVersion(Version);
  bool AddrSizeOK = AddrSize == 4 || AddrSize == 8;

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

  Abbrevs = Abbrev->getAbbreviationDeclarationSet(AbbrOffset);
  if (Abbrevs == nullptr)
    return false;

  return true;
}

static size_t
ReadCStringFromMemory (ExecutionContextScope *exe_scope, const Address &address, Stream *strm)
{
    if (exe_scope == NULL)
        return 0;
    const size_t k_buf_len = 256;
    char buf[k_buf_len+1];
    buf[k_buf_len] = '\0'; // NULL terminate

    // Byte order and address size don't matter for C string dumping..
    DataExtractor data (buf, sizeof(buf), lldb::endian::InlHostByteOrder(), 4);
    size_t total_len = 0;
    size_t bytes_read;
    Address curr_address(address);
    strm->PutChar ('"');
    while ((bytes_read = ReadBytes (exe_scope, curr_address, buf, k_buf_len)) > 0)
    {
        size_t len = strlen(buf);
        if (len == 0)
            break;
        if (len > bytes_read)
            len = bytes_read;

        data.Dump (strm,
                   0,                 // Start offset in "data"
                   eFormatChar,       // Print as characters
                   1,                 // Size of item (1 byte for a char!)
                   len,               // How many bytes to print?
                   UINT32_MAX,        // num per line
                   LLDB_INVALID_ADDRESS,// base address
                   0,                 // bitfield bit size

                   0);                // bitfield bit offset

        total_len += bytes_read;

        if (len < k_buf_len)
            break;
        curr_address.SetOffset (curr_address.GetOffset() + bytes_read);
    }
    strm->PutChar ('"');
    return total_len;
}

bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, uint32_t *OffsetPtr,
                                      const DataExtractor &DebugInfoData,
                                      uint32_t UEndOffset, uint32_t D) {
  Offset = *OffsetPtr;
  Depth = D;
  if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset))
    return false;
  uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
  if (0 == AbbrCode) {
    // NULL debug tag entry.
    AbbrevDecl = nullptr;
    return true;
  }
  AbbrevDecl = U.getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
  if (nullptr == AbbrevDecl) {
    // Restore the original offset.
    *OffsetPtr = Offset;
    return false;
  }
  // See if all attributes in this DIE have fixed byte sizes. If so, we can
  // just add this size to the offset to skip to the next DIE.
  if (Optional<size_t> FixedSize = AbbrevDecl->getFixedAttributesByteSize(U)) {
    *OffsetPtr += *FixedSize;
    return true;
  }

  // Skip all data in the .debug_info for the attributes
  for (const auto &AttrSpec : AbbrevDecl->attributes()) {
    // Check if this attribute has a fixed byte size.
    if (auto FixedSize = AttrSpec.getByteSize(U)) {
      // Attribute byte size if fixed, just add the size to the offset.
      *OffsetPtr += *FixedSize;
    } else if (!DWARFFormValue::skipValue(AttrSpec.Form, DebugInfoData,
                                          OffsetPtr, &U)) {
      // We failed to skip this attribute's value, restore the original offset
      // and return the failure status.
      *OffsetPtr = Offset;
      return false;
    }
  }
  return true;
}

static bool GetAPInt(const DataExtractor &data, lldb::offset_t *offset_ptr,
                     lldb::offset_t byte_size, llvm::APInt &result) {
  llvm::SmallVector<uint64_t, 2> uint64_array;
  lldb::offset_t bytes_left = byte_size;
  uint64_t u64;
  const lldb::ByteOrder byte_order = data.GetByteOrder();
  if (byte_order == lldb::eByteOrderLittle) {
    while (bytes_left > 0) {
      if (bytes_left >= 8) {
        u64 = data.GetU64(offset_ptr);
        bytes_left -= 8;
      } else {
        u64 = data.GetMaxU64(offset_ptr, (uint32_t)bytes_left);
        bytes_left = 0;
      }
      uint64_array.push_back(u64);
    }
    result = llvm::APInt(byte_size * 8, llvm::ArrayRef<uint64_t>(uint64_array));
    return true;
  } else if (byte_order == lldb::eByteOrderBig) {
    lldb::offset_t be_offset = *offset_ptr + byte_size;
    lldb::offset_t temp_offset;
    while (bytes_left > 0) {
      if (bytes_left >= 8) {
        be_offset -= 8;
        temp_offset = be_offset;
        u64 = data.GetU64(&temp_offset);
        bytes_left -= 8;
      } else {
        be_offset -= bytes_left;
        temp_offset = be_offset;
        u64 = data.GetMaxU64(&temp_offset, (uint32_t)bytes_left);
        bytes_left = 0;
      }
      uint64_array.push_back(u64);
    }
    *offset_ptr += byte_size;
    result = llvm::APInt(byte_size * 8, llvm::ArrayRef<uint64_t>(uint64_array));
    return true;
  }
  return false;
}

bool
ObjectContainerBSDArchive::MagicBytesMatch (const DataExtractor &data)
{
    uint32_t offset = 0;
    const char* armag = (const char* )data.PeekData (offset, sizeof(ar_hdr));
    if (armag && ::strncmp(armag, ARMAG, SARMAG) == 0)
    {
        armag += offsetof(struct ar_hdr, ar_fmag) + SARMAG;
        if (strncmp(armag, ARFMAG, 2) == 0)
            return true;
    }

ObjectContainer *ObjectContainerUniversalMachO::CreateInstance(
    const lldb::ModuleSP &module_sp, DataBufferSP &data_sp,
    lldb::offset_t data_offset, const FileSpec *file,
    lldb::offset_t file_offset, lldb::offset_t length) {
  // We get data when we aren't trying to look for cached container information,
  // so only try and look for an architecture slice if we get data
  if (data_sp) {
    DataExtractor data;
    data.SetData(data_sp, data_offset, length);
    if (ObjectContainerUniversalMachO::MagicBytesMatch(data)) {
      std::unique_ptr<ObjectContainerUniversalMachO> container_ap(
          new ObjectContainerUniversalMachO(module_sp, data_sp, data_offset,
                                            file, file_offset, length));
      if (container_ap->ParseHeader()) {
        return container_ap.release();
      }
    }
  }
  return NULL;
}

RegisterContextCorePOSIX_x86_64::RegisterContextCorePOSIX_x86_64(
    Thread &thread, RegisterInfoInterface *register_info,
    const DataExtractor &gpregset, const DataExtractor &fpregset)
    : RegisterContextPOSIX_x86(thread, 0, register_info) {
  size_t size, len;

  size = GetGPRSize();
  m_gpregset.reset(new uint8_t[size]);
  len =
      gpregset.ExtractBytes(0, size, lldb::eByteOrderLittle, m_gpregset.get());
  if (len != size)
    m_gpregset.reset();

  size = sizeof(FXSAVE);
  m_fpregset.reset(new uint8_t[size]);
  len =
      fpregset.ExtractBytes(0, size, lldb::eByteOrderLittle, m_fpregset.get());
  if (len != size)
    m_fpregset.reset();
}

lldb::offset_t
ObjectContainerBSDArchive::Object::Extract (const DataExtractor& data, lldb::offset_t offset)
{
    size_t ar_name_len = 0;
    std::string str;
    char *err;
    str.assign ((const char *)data.GetData(&offset, 16),    16);
    if (str.find("#1/") == 0)
    {
        // If the name is longer than 16 bytes, or contains an embedded space
        // then it will use this format where the length of the name is
        // here and the name characters are after this header.
        ar_name_len = strtoul(str.c_str() + 3, &err, 10);
    }
    else
    {
        // Strip off any spaces (if the object file name contains spaces it
        // will use the extended format above).
        str.erase (str.find(' '));
        ar_name.SetCString(str.c_str());
    }

    str.assign ((const char *)data.GetData(&offset, 12),    12);
    ar_date = strtoul(str.c_str(), &err, 10);

    str.assign ((const char *)data.GetData(&offset, 6), 6);
    ar_uid  = strtoul(str.c_str(), &err, 10);

    str.assign ((const char *)data.GetData(&offset, 6), 6);
    ar_gid  = strtoul(str.c_str(), &err, 10);

    str.assign ((const char *)data.GetData(&offset, 8), 8);
    ar_mode = strtoul(str.c_str(), &err, 8);

    str.assign ((const char *)data.GetData(&offset, 10),    10);
    ar_size = strtoul(str.c_str(), &err, 10);

    str.assign ((const char *)data.GetData(&offset, 2), 2);
    if (str == ARFMAG)
    {
        if (ar_name_len > 0)
        {
            str.assign ((const char *)data.GetData(&offset, ar_name_len), ar_name_len);
            ar_name.SetCString (str.c_str());
        }
        ar_file_offset = offset;
        ar_file_size = ar_size - ar_name_len;
        return offset;
    }
    return LLDB_INVALID_OFFSET;
}

size_t
Disassembler::ParseInstructions
(
    const ExecutionContext *exe_ctx,
    const AddressRange &range,
    DataExtractor& data
)
{
    Target *target = exe_ctx->target;

    const addr_t byte_size = range.GetByteSize();
    if (target == NULL || byte_size == 0 || !range.GetBaseAddress().IsValid())
        return 0;

    DataBufferHeap *heap_buffer = new DataBufferHeap (byte_size, '\0');
    DataBufferSP data_sp(heap_buffer);

    Error error;
    const size_t bytes_read = target->ReadMemory (range.GetBaseAddress(), heap_buffer->GetBytes(), heap_buffer->GetByteSize(), error);
    
    if (bytes_read > 0)
    {
        if (bytes_read != heap_buffer->GetByteSize())
            heap_buffer->SetByteSize (bytes_read);

        data.SetData(data_sp);
        if (exe_ctx->process)
        {
            data.SetByteOrder(exe_ctx->process->GetByteOrder());
            data.SetAddressByteSize(exe_ctx->process->GetAddressByteSize());
        }
        else
        {
            data.SetByteOrder(target->GetArchitecture().GetDefaultEndian());
            data.SetAddressByteSize(target->GetArchitecture().GetAddressByteSize());
        }
        return DecodeInstructions (data, 0, UINT32_MAX);
    }

    return 0;
}

size_t ObjectFilePECOFF::GetModuleSpecifications(
    const lldb_private::FileSpec &file, lldb::DataBufferSP &data_sp,
    lldb::offset_t data_offset, lldb::offset_t file_offset,
    lldb::offset_t length, lldb_private::ModuleSpecList &specs) {
  const size_t initial_count = specs.GetSize();

  if (ObjectFilePECOFF::MagicBytesMatch(data_sp)) {
    DataExtractor data;
    data.SetData(data_sp, data_offset, length);
    data.SetByteOrder(eByteOrderLittle);

    dos_header_t dos_header;
    coff_header_t coff_header;

    if (ParseDOSHeader(data, dos_header)) {
      lldb::offset_t offset = dos_header.e_lfanew;
      uint32_t pe_signature = data.GetU32(&offset);
      if (pe_signature != IMAGE_NT_SIGNATURE)
        return false;
      if (ParseCOFFHeader(data, &offset, coff_header)) {
        ArchSpec spec;
        if (coff_header.machine == MachineAmd64) {
          spec.SetTriple("x86_64-pc-windows");
          specs.Append(ModuleSpec(file, spec));
        } else if (coff_header.machine == MachineX86) {
          spec.SetTriple("i386-pc-windows");
          specs.Append(ModuleSpec(file, spec));
          spec.SetTriple("i686-pc-windows");
          specs.Append(ModuleSpec(file, spec));
        }
        else if (coff_header.machine == MachineArmNt)
        {
          spec.SetTriple("arm-pc-windows");
          specs.Append(ModuleSpec(file, spec));
        }
      }
    }
  }

  return specs.GetSize() - initial_count;
}

//----------------------------------------------------------------------
// Get the section data from a complete contiguous copy of the
// entire executable image.
//----------------------------------------------------------------------
size_t
Section::GetSectionDataFromImage (const DataExtractor& image_data, DataExtractor& section_data) const
{
    size_t file_size = GetByteSize();
    if (file_size > 0)
    {
        off_t file_offset = GetFileOffset();
        if (section_data.SetData (image_data, file_offset, file_size) == file_size)
            return true;
    }
    return false;
}

Scalar &
Value::ResolveValue(ExecutionContext *exe_ctx, clang::ASTContext *ast_context)
{    
    void *opaque_clang_qual_type = GetClangType();
    if (opaque_clang_qual_type)
    {
        switch (m_value_type)
        {
        case eValueTypeScalar:               // raw scalar value
            break;

        default:
        case eValueTypeFileAddress:
            m_value.Clear();
            break;

        case eValueTypeLoadAddress:          // load address value
        case eValueTypeHostAddress:          // host address value (for memory in the process that is using liblldb)
            {
                AddressType address_type = m_value_type == eValueTypeLoadAddress ? eAddressTypeLoad : eAddressTypeHost;
                lldb::addr_t addr = m_value.ULongLong(LLDB_INVALID_ADDRESS);
                DataExtractor data;
                if (ClangASTType::ReadFromMemory (ast_context, opaque_clang_qual_type, exe_ctx, addr, address_type, data))
                {
                    Scalar scalar;
                    if (ClangASTType::GetValueAsScalar (ast_context, opaque_clang_qual_type, data, 0, data.GetByteSize(), scalar))
                    {
                        m_value = scalar;
                        m_value_type = eValueTypeScalar;
                    }
                    else
                    {
                        if ((uintptr_t)addr != (uintptr_t)m_data_buffer.GetBytes())
                        {
                            m_value.Clear();
                            m_value_type = eValueTypeScalar;
                        }
                    }
                }
                else
                {
                    if ((uintptr_t)addr != (uintptr_t)m_data_buffer.GetBytes())
                    {
                        m_value.Clear();
                        m_value_type = eValueTypeScalar;
                    }
                }
            }
            break;
        }
    }
    return m_value;
}

/// State transition when a NewBufferRecord is encountered.
Error processFDRNewBufferRecord(FDRState &State, uint8_t RecordFirstByte,
                                DataExtractor &RecordExtractor) {

  if (State.Expects != FDRState::Token::NEW_BUFFER_RECORD_OR_EOF)
    return make_error<StringError>(
        "Malformed log. Read New Buffer record kind out of sequence",
        std::make_error_code(std::errc::executable_format_error));
  uint32_t OffsetPtr = 1; // 1 byte into record.
  State.ThreadId = RecordExtractor.getU16(&OffsetPtr);
  State.Expects = FDRState::Token::WALLCLOCK_RECORD;
  return Error::success();
}