C++ DataExtractor::getCStr方法代码示例

bool DWARFDebugLine::Prologue::parse(DataExtractor debug_line_data,
                                     uint32_t *offset_ptr) {
  const uint32_t prologue_offset = *offset_ptr;

  clear();
  TotalLength = debug_line_data.getU32(offset_ptr);
  Version = debug_line_data.getU16(offset_ptr);
  if (Version < 2)
    return false;

  PrologueLength = debug_line_data.getU32(offset_ptr);
  const uint32_t end_prologue_offset = PrologueLength + *offset_ptr;
  MinInstLength = debug_line_data.getU8(offset_ptr);
  if (Version >= 4)
    MaxOpsPerInst = debug_line_data.getU8(offset_ptr);
  DefaultIsStmt = debug_line_data.getU8(offset_ptr);
  LineBase = debug_line_data.getU8(offset_ptr);
  LineRange = debug_line_data.getU8(offset_ptr);
  OpcodeBase = debug_line_data.getU8(offset_ptr);

  StandardOpcodeLengths.reserve(OpcodeBase - 1);
  for (uint32_t i = 1; i < OpcodeBase; ++i) {
    uint8_t op_len = debug_line_data.getU8(offset_ptr);
    StandardOpcodeLengths.push_back(op_len);
  }

  while (*offset_ptr < end_prologue_offset) {
    const char *s = debug_line_data.getCStr(offset_ptr);
    if (s && s[0])
      IncludeDirectories.push_back(s);
    else
      break;
  }

  while (*offset_ptr < end_prologue_offset) {
    const char *name = debug_line_data.getCStr(offset_ptr);
    if (name && name[0]) {
      FileNameEntry fileEntry;
      fileEntry.Name = name;
      fileEntry.DirIdx = debug_line_data.getULEB128(offset_ptr);
      fileEntry.ModTime = debug_line_data.getULEB128(offset_ptr);
      fileEntry.Length = debug_line_data.getULEB128(offset_ptr);
      FileNames.push_back(fileEntry);
    } else {
      break;
    }
  }

  if (*offset_ptr != end_prologue_offset) {
    fprintf(stderr, "warning: parsing line table prologue at 0x%8.8x should"
                    " have ended at 0x%8.8x but it ended at 0x%8.8x\n",
            prologue_offset, end_prologue_offset, *offset_ptr);
    return false;
  }
  return true;
}

void DWARFDebugMacro::parse(DataExtractor data) {
  uint32_t Offset = 0;
  while (data.isValidOffset(Offset)) {
    // A macro list entry consists of:
    Entry E;
    // 1. Macinfo type
    E.Type = data.getULEB128(&Offset);

    if (E.Type == 0) {
      // Reached end of ".debug_macinfo" section.
      return;
    }

    switch (E.Type) {
    default:
      // Got a corrupted ".debug_macinfo" section (invalid macinfo type).
      // Push the corrupted entry to the list and halt parsing.
      E.Type = DW_MACINFO_invalid;
      Macros.push_back(E);
      return;
    case DW_MACINFO_define:
    case DW_MACINFO_undef:
      // 2. Source line
      E.Line = data.getULEB128(&Offset);
      // 3. Macro string
      E.MacroStr = data.getCStr(&Offset);
      break;
    case DW_MACINFO_start_file:
      // 2. Source line
      E.Line = data.getULEB128(&Offset);
      // 3. Source file id
      E.File = data.getULEB128(&Offset);
      break;
    case DW_MACINFO_end_file:
      break;
    case DW_MACINFO_vendor_ext:
      // 2. Vendor extension constant
      E.ExtConstant = data.getULEB128(&Offset);
      // 3. Vendor extension string
      E.ExtStr = data.getCStr(&Offset);
      break;
    }

    Macros.push_back(E);
  }
}

static Expected<const char *>
getIndexedString(uint32_t Form, DataExtractor InfoData, uint32_t &InfoOffset,
                 StringRef StrOffsets, StringRef Str) {
  if (Form == dwarf::DW_FORM_string)
    return InfoData.getCStr(&InfoOffset);
  if (Form != dwarf::DW_FORM_GNU_str_index)
    return make_error<DWPError>(
        "string field encoded without DW_FORM_string or DW_FORM_GNU_str_index");
  auto StrIndex = InfoData.getULEB128(&InfoOffset);
  DataExtractor StrOffsetsData(StrOffsets, true, 0);
  uint32_t StrOffsetsOffset = 4 * StrIndex;
  uint32_t StrOffset = StrOffsetsData.getU32(&StrOffsetsOffset);
  DataExtractor StrData(Str, true, 0);
  return StrData.getCStr(&StrOffset);
}

void DWARFDebugFrame::parse(DataExtractor Data) {
  uint32_t Offset = 0;
  DenseMap<uint32_t, CIE *> CIEs;

  while (Data.isValidOffset(Offset)) {
    uint32_t StartOffset = Offset;

    bool IsDWARF64 = false;
    uint64_t Length = Data.getU32(&Offset);
    uint64_t Id;

    if (Length == UINT32_MAX) {
      // DWARF-64 is distinguished by the first 32 bits of the initial length
      // field being 0xffffffff. Then, the next 64 bits are the actual entry
      // length.
      IsDWARF64 = true;
      Length = Data.getU64(&Offset);
    }

    // At this point, Offset points to the next field after Length.
    // Length is the structure size excluding itself. Compute an offset one
    // past the end of the structure (needed to know how many instructions to
    // read).
    // TODO: For honest DWARF64 support, DataExtractor will have to treat
    //       offset_ptr as uint64_t*
    uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length);

    // The Id field's size depends on the DWARF format
    Id = Data.getUnsigned(&Offset, IsDWARF64 ? 8 : 4);
    bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID);

    if (IsCIE) {
      uint8_t Version = Data.getU8(&Offset);
      const char *Augmentation = Data.getCStr(&Offset);
      uint8_t AddressSize = Version < 4 ? Data.getAddressSize() : Data.getU8(&Offset);
      Data.setAddressSize(AddressSize);
      uint8_t SegmentDescriptorSize = Version < 4 ? 0 : Data.getU8(&Offset);
      uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset);
      int64_t DataAlignmentFactor = Data.getSLEB128(&Offset);
      uint64_t ReturnAddressRegister = Data.getULEB128(&Offset);

      auto Cie = make_unique<CIE>(StartOffset, Length, Version,
                                  StringRef(Augmentation), AddressSize,
                                  SegmentDescriptorSize, CodeAlignmentFactor,
                                  DataAlignmentFactor, ReturnAddressRegister);
      CIEs[StartOffset] = Cie.get();
      Entries.emplace_back(std::move(Cie));
    } else {
      // FDE
      uint64_t CIEPointer = Id;
      uint64_t InitialLocation = Data.getAddress(&Offset);
      uint64_t AddressRange = Data.getAddress(&Offset);

      Entries.emplace_back(new FDE(StartOffset, Length, CIEPointer,
                                   InitialLocation, AddressRange,
                                   CIEs[CIEPointer]));
    }

    Entries.back()->parseInstructions(Data, &Offset, EndStructureOffset);

    if (Offset != EndStructureOffset) {
      std::string Str;
      raw_string_ostream OS(Str);
      OS << format("Parsing entry instructions at %lx failed", StartOffset);
      report_fatal_error(Str);
    }
  }
}

bool
DWARFFormValue::skipValue(uint16_t form, DataExtractor debug_info_data,
                          uint32_t *offset_ptr, const DWARFUnit *cu) {
  bool indirect = false;
  do {
    switch (form) {
    // Blocks if inlined data that have a length field and the data bytes
    // inlined in the .debug_info
    case DW_FORM_exprloc:
    case DW_FORM_block: {
      uint64_t size = debug_info_data.getULEB128(offset_ptr);
      *offset_ptr += size;
      return true;
    }
    case DW_FORM_block1: {
      uint8_t size = debug_info_data.getU8(offset_ptr);
      *offset_ptr += size;
      return true;
    }
    case DW_FORM_block2: {
      uint16_t size = debug_info_data.getU16(offset_ptr);
      *offset_ptr += size;
      return true;
    }
    case DW_FORM_block4: {
      uint32_t size = debug_info_data.getU32(offset_ptr);
      *offset_ptr += size;
      return true;
    }

    // Inlined NULL terminated C-strings
    case DW_FORM_string:
      debug_info_data.getCStr(offset_ptr);
      return true;

    // Compile unit address sized values
    case DW_FORM_addr:
      *offset_ptr += cu->getAddressByteSize();
      return true;
    case DW_FORM_ref_addr:
      *offset_ptr += getRefAddrSize(cu->getAddressByteSize(), cu->getVersion());
      return true;

    // 0 byte values - implied from the form.
    case DW_FORM_flag_present:
      return true;

    // 1 byte values
    case DW_FORM_data1:
    case DW_FORM_flag:
    case DW_FORM_ref1:
      *offset_ptr += 1;
      return true;

    // 2 byte values
    case DW_FORM_data2:
    case DW_FORM_ref2:
      *offset_ptr += 2;
      return true;

    // 4 byte values
    case DW_FORM_strp:
    case DW_FORM_data4:
    case DW_FORM_ref4:
      *offset_ptr += 4;
      return true;

    // 8 byte values
    case DW_FORM_data8:
    case DW_FORM_ref8:
    case DW_FORM_ref_sig8:
      *offset_ptr += 8;
      return true;

    // signed or unsigned LEB 128 values
    //  case DW_FORM_APPLE_db_str:
    case DW_FORM_sdata:
    case DW_FORM_udata:
    case DW_FORM_ref_udata:
    case DW_FORM_GNU_str_index:
    case DW_FORM_GNU_addr_index:
      debug_info_data.getULEB128(offset_ptr);
      return true;

    case DW_FORM_indirect:
      indirect = true;
      form = debug_info_data.getULEB128(offset_ptr);
      break;

    // FIXME: 4 for DWARF32, 8 for DWARF64.
    case DW_FORM_sec_offset:
      *offset_ptr += 4;
      return true;

    default:
      return false;
    }
  } while (indirect);
  return true;
}

bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
                                  const DWARFUnit *cu) {
  bool indirect = false;
  bool is_block = false;
  Value.data = nullptr;
  // Read the value for the form into value and follow and DW_FORM_indirect
  // instances we run into
  do {
    indirect = false;
    switch (Form) {
    case DW_FORM_addr:
    case DW_FORM_ref_addr: {
      uint16_t AddrSize =
          (Form == DW_FORM_addr)
              ? cu->getAddressByteSize()
              : getRefAddrSize(cu->getAddressByteSize(), cu->getVersion());
      RelocAddrMap::const_iterator AI = cu->getRelocMap()->find(*offset_ptr);
      if (AI != cu->getRelocMap()->end()) {
        const std::pair<uint8_t, int64_t> &R = AI->second;
        Value.uval = data.getUnsigned(offset_ptr, AddrSize) + R.second;
      } else
        Value.uval = data.getUnsigned(offset_ptr, AddrSize);
      break;
    }
    case DW_FORM_exprloc:
    case DW_FORM_block:
      Value.uval = data.getULEB128(offset_ptr);
      is_block = true;
      break;
    case DW_FORM_block1:
      Value.uval = data.getU8(offset_ptr);
      is_block = true;
      break;
    case DW_FORM_block2:
      Value.uval = data.getU16(offset_ptr);
      is_block = true;
      break;
    case DW_FORM_block4:
      Value.uval = data.getU32(offset_ptr);
      is_block = true;
      break;
    case DW_FORM_data1:
    case DW_FORM_ref1:
    case DW_FORM_flag:
      Value.uval = data.getU8(offset_ptr);
      break;
    case DW_FORM_data2:
    case DW_FORM_ref2:
      Value.uval = data.getU16(offset_ptr);
      break;
    case DW_FORM_data4:
    case DW_FORM_ref4: {
      RelocAddrMap::const_iterator AI = cu->getRelocMap()->find(*offset_ptr);
      Value.uval = data.getU32(offset_ptr);
      if (AI != cu->getRelocMap()->end())
        Value.uval += AI->second.second;
      break;
    }
    case DW_FORM_data8:
    case DW_FORM_ref8:
      Value.uval = data.getU64(offset_ptr);
      break;
    case DW_FORM_sdata:
      Value.sval = data.getSLEB128(offset_ptr);
      break;
    case DW_FORM_strp: {
      RelocAddrMap::const_iterator AI
        = cu->getRelocMap()->find(*offset_ptr);
      if (AI != cu->getRelocMap()->end()) {
        const std::pair<uint8_t, int64_t> &R = AI->second;
        Value.uval = data.getU32(offset_ptr) + R.second;
      } else
        Value.uval = data.getU32(offset_ptr);
      break;
    }
    case DW_FORM_udata:
    case DW_FORM_ref_udata:
      Value.uval = data.getULEB128(offset_ptr);
      break;
    case DW_FORM_string:
      Value.cstr = data.getCStr(offset_ptr);
      break;
    case DW_FORM_indirect:
      Form = data.getULEB128(offset_ptr);
      indirect = true;
      break;
    case DW_FORM_sec_offset: {
      // FIXME: This is 64-bit for DWARF64.
      RelocAddrMap::const_iterator AI
        = cu->getRelocMap()->find(*offset_ptr);
      if (AI != cu->getRelocMap()->end()) {
        const std::pair<uint8_t, int64_t> &R = AI->second;
        Value.uval = data.getU32(offset_ptr) + R.second;
      } else
        Value.uval = data.getU32(offset_ptr);
      break;
    }
    case DW_FORM_flag_present:
      Value.uval = 1;
      break;
//.........这里部分代码省略.........

bool DWARFFormValue::skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
                               uint32_t *OffsetPtr,
                               const DWARFFormParams Params) {
  bool Indirect = false;
  do {
    switch (Form) {
    // Blocks of inlined data that have a length field and the data bytes
    // inlined in the .debug_info.
    case DW_FORM_exprloc:
    case DW_FORM_block: {
      uint64_t size = DebugInfoData.getULEB128(OffsetPtr);
      *OffsetPtr += size;
      return true;
    }
    case DW_FORM_block1: {
      uint8_t size = DebugInfoData.getU8(OffsetPtr);
      *OffsetPtr += size;
      return true;
    }
    case DW_FORM_block2: {
      uint16_t size = DebugInfoData.getU16(OffsetPtr);
      *OffsetPtr += size;
      return true;
    }
    case DW_FORM_block4: {
      uint32_t size = DebugInfoData.getU32(OffsetPtr);
      *OffsetPtr += size;
      return true;
    }

    // Inlined NULL terminated C-strings.
    case DW_FORM_string:
      DebugInfoData.getCStr(OffsetPtr);
      return true;

    case DW_FORM_addr:
    case DW_FORM_ref_addr:
    case DW_FORM_flag_present:
    case DW_FORM_data1:
    case DW_FORM_data2:
    case DW_FORM_data4:
    case DW_FORM_data8:
    case DW_FORM_data16:
    case DW_FORM_flag:
    case DW_FORM_ref1:
    case DW_FORM_ref2:
    case DW_FORM_ref4:
    case DW_FORM_ref8:
    case DW_FORM_ref_sig8:
    case DW_FORM_ref_sup4:
    case DW_FORM_ref_sup8:
    case DW_FORM_strx1:
    case DW_FORM_strx2:
    case DW_FORM_strx4:
    case DW_FORM_addrx1:
    case DW_FORM_addrx2:
    case DW_FORM_addrx4:
    case DW_FORM_sec_offset:
    case DW_FORM_strp:
    case DW_FORM_strp_sup:
    case DW_FORM_line_strp:
    case DW_FORM_GNU_ref_alt:
    case DW_FORM_GNU_strp_alt:
      if (Optional<uint8_t> FixedSize =
              DWARFFormValue::getFixedByteSize(Form, Params)) {
        *OffsetPtr += *FixedSize;
        return true;
      }
      return false;

    // signed or unsigned LEB 128 values.
    case DW_FORM_sdata:
      DebugInfoData.getSLEB128(OffsetPtr);
      return true;

    case DW_FORM_udata:
    case DW_FORM_ref_udata:
    case DW_FORM_strx:
    case DW_FORM_addrx:
    case DW_FORM_loclistx:
    case DW_FORM_rnglistx:
    case DW_FORM_GNU_addr_index:
    case DW_FORM_GNU_str_index:
      DebugInfoData.getULEB128(OffsetPtr);
      return true;

    case DW_FORM_indirect:
      Indirect = true;
      Form = static_cast<dwarf::Form>(DebugInfoData.getULEB128(OffsetPtr));
      break;

    default:
      return false;
    }
  } while (Indirect);
  return true;
}

void DWARFDebugFrame::parse(DataExtractor Data) {
  uint32_t Offset = 0;

  while (Data.isValidOffset(Offset)) {
    uint32_t StartOffset = Offset;

    bool IsDWARF64 = false;
    uint64_t Length = Data.getU32(&Offset);
    uint64_t Id;

    if (Length == UINT32_MAX) {
      // DWARF-64 is distinguished by the first 32 bits of the initial length
      // field being 0xffffffff. Then, the next 64 bits are the actual entry
      // length.
      IsDWARF64 = true;
      Length = Data.getU64(&Offset);
    }

    // At this point, Offset points to the next field after Length.
    // Length is the structure size excluding itself. Compute an offset one
    // past the end of the structure (needed to know how many instructions to
    // read).
    // TODO: For honest DWARF64 support, DataExtractor will have to treat
    //       offset_ptr as uint64_t*
    uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length);

    // The Id field's size depends on the DWARF format
    Id = Data.getUnsigned(&Offset, IsDWARF64 ? 8 : 4);
    bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID);

    if (IsCIE) {
      // Note: this is specifically DWARFv3 CIE header structure. It was
      // changed in DWARFv4. We currently don't support reading DWARFv4
      // here because LLVM itself does not emit it (and LLDB doesn't
      // support it either).
      uint8_t Version = Data.getU8(&Offset);
      const char *Augmentation = Data.getCStr(&Offset);
      uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset);
      int64_t DataAlignmentFactor = Data.getSLEB128(&Offset);
      uint64_t ReturnAddressRegister = Data.getULEB128(&Offset);

      Entries.emplace_back(new CIE(StartOffset, Length, Version,
                                   StringRef(Augmentation), CodeAlignmentFactor,
                                   DataAlignmentFactor, ReturnAddressRegister));
    } else {
      // FDE
      uint64_t CIEPointer = Id;
      uint64_t InitialLocation = Data.getAddress(&Offset);
      uint64_t AddressRange = Data.getAddress(&Offset);

      Entries.emplace_back(new FDE(StartOffset, Length, CIEPointer,
                                   InitialLocation, AddressRange));
    }

    Entries.back()->parseInstructions(Data, &Offset, EndStructureOffset);

    if (Offset != EndStructureOffset) {
      string_ostream Str;
      Str << format("Parsing entry instructions at %lx failed", StartOffset);
      report_fatal_error(Str.str());
    }
  }
}

bool
DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
                             const DWARFCompileUnit *cu) {
  bool indirect = false;
  bool is_block = false;
  Value.data = NULL;
  // Read the value for the form into value and follow and DW_FORM_indirect
  // instances we run into
  do {
    indirect = false;
    switch (Form) {
    case DW_FORM_addr:
    case DW_FORM_ref_addr:
      Value.uval = data.getUnsigned(offset_ptr, cu->getAddressByteSize());
      break;
    case DW_FORM_block:
      Value.uval = data.getULEB128(offset_ptr);
      is_block = true;
      break;
    case DW_FORM_block1:
      Value.uval = data.getU8(offset_ptr);
      is_block = true;
      break;
    case DW_FORM_block2:
      Value.uval = data.getU16(offset_ptr);
      is_block = true;
      break;
    case DW_FORM_block4:
      Value.uval = data.getU32(offset_ptr);
      is_block = true;
      break;
    case DW_FORM_data1:
    case DW_FORM_ref1:
    case DW_FORM_flag:
      Value.uval = data.getU8(offset_ptr);
      break;
    case DW_FORM_data2:
    case DW_FORM_ref2:
      Value.uval = data.getU16(offset_ptr);
      break;
    case DW_FORM_data4:
    case DW_FORM_ref4:
      Value.uval = data.getU32(offset_ptr);
      break;
    case DW_FORM_data8:
    case DW_FORM_ref8:
      Value.uval = data.getU64(offset_ptr);
      break;
    case DW_FORM_sdata:
      Value.sval = data.getSLEB128(offset_ptr);
      break;
    case DW_FORM_strp:
      Value.uval = data.getU32(offset_ptr);
      break;
    case DW_FORM_udata:
    case DW_FORM_ref_udata:
      Value.uval = data.getULEB128(offset_ptr);
      break;
    case DW_FORM_string:
      Value.cstr = data.getCStr(offset_ptr);
      // Set the string value to also be the data for inlined cstr form
      // values only so we can tell the differnence between DW_FORM_string
      // and DW_FORM_strp form values
      Value.data = (uint8_t*)Value.cstr;
      break;
    case DW_FORM_indirect:
      Form = data.getULEB128(offset_ptr);
      indirect = true;
      break;
    default:
      return false;
    }
  } while (indirect);

  if (is_block) {
    StringRef str = data.getData().substr(*offset_ptr, Value.uval);
    Value.data = NULL;
    if (!str.empty()) {
      Value.data = reinterpret_cast<const uint8_t *>(str.data());
      *offset_ptr += Value.uval;
    }
  }

  return true;
}

bool
DWARFDebugLine::parseStatementTable(DataExtractor debug_line_data,
                                    uint32_t *offset_ptr, State &state) {
  const uint32_t debug_line_offset = *offset_ptr;

  Prologue *prologue = &state.Prologue;

  if (!parsePrologue(debug_line_data, offset_ptr, prologue)) {
    // Restore our offset and return false to indicate failure!
    *offset_ptr = debug_line_offset;
    return false;
  }

  const uint32_t end_offset = debug_line_offset + prologue->TotalLength +
                              sizeof(prologue->TotalLength);

  state.reset();

  while (*offset_ptr < end_offset) {
    uint8_t opcode = debug_line_data.getU8(offset_ptr);

    if (opcode == 0) {
      // Extended Opcodes always start with a zero opcode followed by
      // a uleb128 length so you can skip ones you don't know about
      uint32_t ext_offset = *offset_ptr;
      uint64_t len = debug_line_data.getULEB128(offset_ptr);
      uint32_t arg_size = len - (*offset_ptr - ext_offset);

      uint8_t sub_opcode = debug_line_data.getU8(offset_ptr);
      switch (sub_opcode) {
      case DW_LNE_end_sequence:
        // Set the end_sequence register of the state machine to true and
        // append a row to the matrix using the current values of the
        // state-machine registers. Then reset the registers to the initial
        // values specified above. Every statement program sequence must end
        // with a DW_LNE_end_sequence instruction which creates a row whose
        // address is that of the byte after the last target machine instruction
        // of the sequence.
        state.EndSequence = true;
        state.appendRowToMatrix(*offset_ptr);
        state.reset();
        break;

      case DW_LNE_set_address:
        // Takes a single relocatable address as an operand. The size of the
        // operand is the size appropriate to hold an address on the target
        // machine. Set the address register to the value given by the
        // relocatable address. All of the other statement program opcodes
        // that affect the address register add a delta to it. This instruction
        // stores a relocatable value into it instead.
        state.Address = debug_line_data.getAddress(offset_ptr);
        break;

      case DW_LNE_define_file:
        // Takes 4 arguments. The first is a null terminated string containing
        // a source file name. The second is an unsigned LEB128 number
        // representing the directory index of the directory in which the file
        // was found. The third is an unsigned LEB128 number representing the
        // time of last modification of the file. The fourth is an unsigned
        // LEB128 number representing the length in bytes of the file. The time
        // and length fields may contain LEB128(0) if the information is not
        // available.
        //
        // The directory index represents an entry in the include_directories
        // section of the statement program prologue. The index is LEB128(0)
        // if the file was found in the current directory of the compilation,
        // LEB128(1) if it was found in the first directory in the
        // include_directories section, and so on. The directory index is
        // ignored for file names that represent full path names.
        //
        // The files are numbered, starting at 1, in the order in which they
        // appear; the names in the prologue come before names defined by
        // the DW_LNE_define_file instruction. These numbers are used in the
        // the file register of the state machine.
        {
          FileNameEntry fileEntry;
          fileEntry.Name = debug_line_data.getCStr(offset_ptr);
          fileEntry.DirIdx = debug_line_data.getULEB128(offset_ptr);
          fileEntry.ModTime = debug_line_data.getULEB128(offset_ptr);
          fileEntry.Length = debug_line_data.getULEB128(offset_ptr);
          prologue->FileNames.push_back(fileEntry);
        }
        break;

      default:
        // Length doesn't include the zero opcode byte or the length itself, but
        // it does include the sub_opcode, so we have to adjust for that below
        (*offset_ptr) += arg_size;
        break;
      }
    } else if (opcode < prologue->OpcodeBase) {
      switch (opcode) {
      // Standard Opcodes
      case DW_LNS_copy:
        // Takes no arguments. Append a row to the matrix using the
        // current values of the state-machine registers. Then set
        // the basic_block register to false.
        state.appendRowToMatrix(*offset_ptr);
        break;

//.........这里部分代码省略.........

void DWARFDebugFrame::parse(DataExtractor Data) {
  uint32_t Offset = 0;
  DenseMap<uint32_t, CIE *> CIEs;

  while (Data.isValidOffset(Offset)) {
    uint32_t StartOffset = Offset;

    auto ReportError = [StartOffset](const char *ErrorMsg) {
      std::string Str;
      raw_string_ostream OS(Str);
      OS << format(ErrorMsg, StartOffset);
      OS.flush();
      report_fatal_error(Str);
    };

    bool IsDWARF64 = false;
    uint64_t Length = Data.getU32(&Offset);
    uint64_t Id;

    if (Length == UINT32_MAX) {
      // DWARF-64 is distinguished by the first 32 bits of the initial length
      // field being 0xffffffff. Then, the next 64 bits are the actual entry
      // length.
      IsDWARF64 = true;
      Length = Data.getU64(&Offset);
    }

    // At this point, Offset points to the next field after Length.
    // Length is the structure size excluding itself. Compute an offset one
    // past the end of the structure (needed to know how many instructions to
    // read).
    // TODO: For honest DWARF64 support, DataExtractor will have to treat
    //       offset_ptr as uint64_t*
    uint32_t StartStructureOffset = Offset;
    uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length);

    // The Id field's size depends on the DWARF format
    Id = Data.getUnsigned(&Offset, (IsDWARF64 && !IsEH) ? 8 : 4);
    bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) ||
                  Id == DW_CIE_ID ||
                  (IsEH && !Id));

    if (IsCIE) {
      uint8_t Version = Data.getU8(&Offset);
      const char *Augmentation = Data.getCStr(&Offset);
      StringRef AugmentationString(Augmentation ? Augmentation : "");
      uint8_t AddressSize = Version < 4 ? Data.getAddressSize() :
                                          Data.getU8(&Offset);
      Data.setAddressSize(AddressSize);
      uint8_t SegmentDescriptorSize = Version < 4 ? 0 : Data.getU8(&Offset);
      uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset);
      int64_t DataAlignmentFactor = Data.getSLEB128(&Offset);
      uint64_t ReturnAddressRegister = Data.getULEB128(&Offset);

      // Parse the augmentation data for EH CIEs
      StringRef AugmentationData("");
      uint32_t FDEPointerEncoding = DW_EH_PE_omit;
      uint32_t LSDAPointerEncoding = DW_EH_PE_omit;
      if (IsEH) {
        Optional<uint32_t> PersonalityEncoding;
        Optional<uint64_t> Personality;

        Optional<uint64_t> AugmentationLength;
        uint32_t StartAugmentationOffset;
        uint32_t EndAugmentationOffset;

        // Walk the augmentation string to get all the augmentation data.
        for (unsigned i = 0, e = AugmentationString.size(); i != e; ++i) {
          switch (AugmentationString[i]) {
            default:
              ReportError("Unknown augmentation character in entry at %lx");
            case 'L':
              LSDAPointerEncoding = Data.getU8(&Offset);
              break;
            case 'P': {
              if (Personality)
                ReportError("Duplicate personality in entry at %lx");
              PersonalityEncoding = Data.getU8(&Offset);
              Personality = readPointer(Data, Offset, *PersonalityEncoding);
              break;
            }
            case 'R':
              FDEPointerEncoding = Data.getU8(&Offset);
              break;
            case 'z':
              if (i)
                ReportError("'z' must be the first character at %lx");
              // Parse the augmentation length first.  We only parse it if
              // the string contains a 'z'.
              AugmentationLength = Data.getULEB128(&Offset);
              StartAugmentationOffset = Offset;
              EndAugmentationOffset = Offset +
                static_cast<uint32_t>(*AugmentationLength);
          }
        }

        if (AugmentationLength.hasValue()) {
          if (Offset != EndAugmentationOffset)
            ReportError("Parsing augmentation data at %lx failed");

//.........这里部分代码省略.........

bool DWARFDebugLine::LineTable::parse(DataExtractor debug_line_data,
                                      const RelocAddrMap *RMap,
                                      uint32_t *offset_ptr) {
  const uint32_t debug_line_offset = *offset_ptr;

  clear();

  if (!Prologue.parse(debug_line_data, offset_ptr)) {
    // Restore our offset and return false to indicate failure!
    *offset_ptr = debug_line_offset;
    return false;
  }

  const uint32_t end_offset =
      debug_line_offset + Prologue.TotalLength + Prologue.sizeofTotalLength();

  ParsingState State(this);

  while (*offset_ptr < end_offset) {
    uint8_t opcode = debug_line_data.getU8(offset_ptr);

    if (opcode == 0) {
      // Extended Opcodes always start with a zero opcode followed by
      // a uleb128 length so you can skip ones you don't know about
      uint32_t ext_offset = *offset_ptr;
      uint64_t len = debug_line_data.getULEB128(offset_ptr);
      uint32_t arg_size = len - (*offset_ptr - ext_offset);

      uint8_t sub_opcode = debug_line_data.getU8(offset_ptr);
      switch (sub_opcode) {
      case DW_LNE_end_sequence:
        // Set the end_sequence register of the state machine to true and
        // append a row to the matrix using the current values of the
        // state-machine registers. Then reset the registers to the initial
        // values specified above. Every statement program sequence must end
        // with a DW_LNE_end_sequence instruction which creates a row whose
        // address is that of the byte after the last target machine instruction
        // of the sequence.
        State.Row.EndSequence = true;
        State.appendRowToMatrix(*offset_ptr);
        State.resetRowAndSequence();
        break;

      case DW_LNE_set_address:
        // Takes a single relocatable address as an operand. The size of the
        // operand is the size appropriate to hold an address on the target
        // machine. Set the address register to the value given by the
        // relocatable address. All of the other statement program opcodes
        // that affect the address register add a delta to it. This instruction
        // stores a relocatable value into it instead.
        {
          // If this address is in our relocation map, apply the relocation.
          RelocAddrMap::const_iterator AI = RMap->find(*offset_ptr);
          if (AI != RMap->end()) {
            const std::pair<uint8_t, int64_t> &R = AI->second;
            State.Row.Address =
                debug_line_data.getAddress(offset_ptr) + R.second;
          } else
            State.Row.Address = debug_line_data.getAddress(offset_ptr);
        }
        break;

      case DW_LNE_define_file:
        // Takes 4 arguments. The first is a null terminated string containing
        // a source file name. The second is an unsigned LEB128 number
        // representing the directory index of the directory in which the file
        // was found. The third is an unsigned LEB128 number representing the
        // time of last modification of the file. The fourth is an unsigned
        // LEB128 number representing the length in bytes of the file. The time
        // and length fields may contain LEB128(0) if the information is not
        // available.
        //
        // The directory index represents an entry in the include_directories
        // section of the statement program prologue. The index is LEB128(0)
        // if the file was found in the current directory of the compilation,
        // LEB128(1) if it was found in the first directory in the
        // include_directories section, and so on. The directory index is
        // ignored for file names that represent full path names.
        //
        // The files are numbered, starting at 1, in the order in which they
        // appear; the names in the prologue come before names defined by
        // the DW_LNE_define_file instruction. These numbers are used in the
        // the file register of the state machine.
        {
          FileNameEntry fileEntry;
          fileEntry.Name = debug_line_data.getCStr(offset_ptr);
          fileEntry.DirIdx = debug_line_data.getULEB128(offset_ptr);
          fileEntry.ModTime = debug_line_data.getULEB128(offset_ptr);
          fileEntry.Length = debug_line_data.getULEB128(offset_ptr);
          Prologue.FileNames.push_back(fileEntry);
        }
        break;

      case DW_LNE_set_discriminator:
        State.Row.Discriminator = debug_line_data.getULEB128(offset_ptr);
        break;

      default:
        // Length doesn't include the zero opcode byte or the length itself, but
        // it does include the sub_opcode, so we have to adjust for that below
//.........这里部分代码省略.........