C++ DataExtractor::getU8方法代码示例

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

  prologue->clear();
  prologue->TotalLength = debug_line_data.getU32(offset_ptr);
  prologue->Version = debug_line_data.getU16(offset_ptr);
  if (prologue->Version != 2)
    return false;

  prologue->PrologueLength = debug_line_data.getU32(offset_ptr);
  const uint32_t end_prologue_offset = prologue->PrologueLength + *offset_ptr;
  prologue->MinInstLength = debug_line_data.getU8(offset_ptr);
  prologue->DefaultIsStmt = debug_line_data.getU8(offset_ptr);
  prologue->LineBase = debug_line_data.getU8(offset_ptr);
  prologue->LineRange = debug_line_data.getU8(offset_ptr);
  prologue->OpcodeBase = debug_line_data.getU8(offset_ptr);

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

  while (*offset_ptr < end_prologue_offset) {
    const char *s = debug_line_data.getCStr(offset_ptr);
    if (s && s[0])
      prologue->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);
      prologue->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;
}

bool
DWARFAbbreviationDeclaration::extract(DataExtractor data, uint32_t* offset_ptr,
                                      uint32_t code) {
  Code = code;
  Attribute.clear();
  if (Code) {
    Tag = data.getULEB128(offset_ptr);
    HasChildren = data.getU8(offset_ptr);

    while (data.isValidOffset(*offset_ptr)) {
      uint16_t attr = data.getULEB128(offset_ptr);
      uint16_t form = data.getULEB128(offset_ptr);

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

    return Tag != 0;
  } else {
    Tag = 0;
    HasChildren = false;
  }

  return false;
}

void DWARFDebugLocDWO::parse(DataExtractor data) {
  uint32_t Offset = 0;
  while (data.isValidOffset(Offset)) {
    Locations.resize(Locations.size() + 1);
    LocationList &Loc = Locations.back();
    Loc.Offset = Offset;
    dwarf::LocationListEntry Kind;
    while ((Kind = static_cast<dwarf::LocationListEntry>(
                data.getU8(&Offset))) != dwarf::DW_LLE_end_of_list) {

      if (Kind != dwarf::DW_LLE_startx_length) {
        llvm::errs() << "error: dumping support for LLE of kind " << (int)Kind
                     << " not implemented\n";
        return;
      }

      Entry E;

      E.Start = data.getULEB128(&Offset);
      E.Length = data.getU32(&Offset);

      unsigned Bytes = data.getU16(&Offset);
      // A single location description describing the location of the object...
      StringRef str = data.getData().substr(Offset, Bytes);
      Offset += Bytes;
      E.Loc.resize(str.size());
      std::copy(str.begin(), str.end(), E.Loc.begin());

      Loc.Entries.push_back(std::move(E));
    }
  }
}

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);
  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;
  }
  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);
  return Abbrevs != nullptr;
}

Optional<DWARFDebugLocDWO::LocationList>
DWARFDebugLocDWO::parseOneLocationList(DataExtractor Data, unsigned *Offset) {
  LocationList LL;
  LL.Offset = *Offset;

  // dwarf::DW_LLE_end_of_list_entry is 0 and indicates the end of the list.
  while (auto Kind =
             static_cast<dwarf::LocationListEntry>(Data.getU8(Offset))) {
    if (Kind != dwarf::DW_LLE_startx_length) {
      llvm::errs() << "error: dumping support for LLE of kind " << (int)Kind
                   << " not implemented\n";
      return None;
    }

    Entry E;
    E.Start = Data.getULEB128(Offset);
    E.Length = Data.getU32(Offset);

    unsigned Bytes = Data.getU16(Offset);
    // A single location description describing the location of the object...
    StringRef str = Data.getData().substr(*Offset, Bytes);
    *Offset += Bytes;
    E.Loc.resize(str.size());
    std::copy(str.begin(), str.end(), E.Loc.begin());

    LL.Entries.push_back(std::move(E));
  }
  return LL;
}

bool DWARFCompileUnit::extract(DataExtractor debug_info, uint32_t *offset_ptr) {
  clear();

  Offset = *offset_ptr;

  if (debug_info.isValidOffset(*offset_ptr)) {
    uint64_t abbrOffset;
    Length = debug_info.getU32(offset_ptr);
    Version = debug_info.getU16(offset_ptr);
    abbrOffset = debug_info.getU32(offset_ptr);
    AddrSize = debug_info.getU8(offset_ptr);

    bool lengthOK = debug_info.isValidOffset(getNextCompileUnitOffset()-1);
    bool versionOK = DWARFContext::isSupportedVersion(Version);
    bool abbrOffsetOK = AbbrevSection.size() > abbrOffset;
    bool addrSizeOK = AddrSize == 4 || AddrSize == 8;

    if (lengthOK && versionOK && addrSizeOK && abbrOffsetOK && Abbrev != NULL) {
      Abbrevs = Abbrev->getAbbreviationDeclarationSet(abbrOffset);
      return true;
    }

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

  return false;
}

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 DWARFUnit::extractImpl(DataExtractor debug_info, uint32_t *offset_ptr) {
  Length = debug_info.getU32(offset_ptr);
  // FIXME: Support DWARF64.
  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.getU32(offset_ptr);
    FormParams.AddrSize = debug_info.getU8(offset_ptr);
  }
  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;
  }

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

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

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

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 abbrOffsetOK = AbbrevSection.size() > abbrOffset;
  bool addrSizeOK = AddrSize == 4 || AddrSize == 8;

  if (!lengthOK || !versionOK || !addrSizeOK || !abbrOffsetOK)
    return false;

  Abbrevs = Abbrev->getAbbreviationDeclarationSet(abbrOffset);
  return true;
}

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;
}

uint32_t
DWARFCompileUnit::extract(uint32_t offset, DataExtractor debug_info_data,
                          const DWARFAbbreviationDeclarationSet *abbrevs) {
  clear();

  Offset = offset;

  if (debug_info_data.isValidOffset(offset)) {
    Length = debug_info_data.getU32(&offset);
    Version = debug_info_data.getU16(&offset);
    bool abbrevsOK = debug_info_data.getU32(&offset) == abbrevs->getOffset();
    Abbrevs = abbrevs;
    AddrSize = debug_info_data.getU8(&offset);

    bool versionOK = DWARFContext::isSupportedVersion(Version);
    bool addrSizeOK = AddrSize == 4 || AddrSize == 8;

    if (versionOK && addrSizeOK && abbrevsOK &&
        debug_info_data.isValidOffset(offset))
      return offset;
  }
  return 0;
}

bool DWARFDebugLine::Prologue::parse(DataExtractor debug_line_data,
                                     uint32_t *offset_ptr) {
  const uint64_t prologue_offset = *offset_ptr;

  clear();
  TotalLength = debug_line_data.getU32(offset_ptr);
  if (TotalLength == UINT32_MAX) {
    IsDWARF64 = true;
    TotalLength = debug_line_data.getU64(offset_ptr);
  } else if (TotalLength > 0xffffff00) {
    return false;
  }
  Version = debug_line_data.getU16(offset_ptr);
  if (Version < 2)
    return false;

  PrologueLength =
      debug_line_data.getUnsigned(offset_ptr, sizeofPrologueLength());
  const uint64_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%8.8" PRIx64
                    " should have ended at 0x%8.8" PRIx64
                    " but it ended at 0x%8.8" PRIx64 "\n",
            prologue_offset, end_prologue_offset, (uint64_t)*offset_ptr);
    return false;
  }
  return true;
}

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
DWARFAbbreviationDeclaration::extract(DataExtractor Data, 
                                      uint32_t* OffsetPtr) {
  clear();
  const uint32_t Offset = *OffsetPtr;
  Code = Data.getULEB128(OffsetPtr);
  if (Code == 0) {
    return false;
  }
  CodeByteSize = *OffsetPtr - Offset;
  Tag = static_cast<llvm::dwarf::Tag>(Data.getULEB128(OffsetPtr));
  if (Tag == DW_TAG_null) {
    clear();
    return false;
  }
  uint8_t ChildrenByte = Data.getU8(OffsetPtr);
  HasChildren = (ChildrenByte == DW_CHILDREN_yes);
  // Assign a value to our optional FixedAttributeSize member variable. If
  // this member variable still has a value after the while loop below, then
  // all attribute data in this abbreviation declaration has a fixed byte size.
  FixedAttributeSize = FixedSizeInfo();

  // Read all of the abbreviation attributes and forms.
  while (true) {
    auto A = static_cast<Attribute>(Data.getULEB128(OffsetPtr));
    auto F = static_cast<Form>(Data.getULEB128(OffsetPtr));
    if (A && F) {
      auto FixedFormByteSize = DWARFFormValue::getFixedByteSize(F);
      AttributeSpecs.push_back(AttributeSpec(A, F, FixedFormByteSize));
      // If this abbrevation still has a fixed byte size, then update the
      // FixedAttributeSize as needed.
      if (FixedAttributeSize) {
        if (FixedFormByteSize)
          FixedAttributeSize->NumBytes += *FixedFormByteSize;
        else {
          switch (F) {
          case DW_FORM_addr:
            ++FixedAttributeSize->NumAddrs;
            break;

          case DW_FORM_ref_addr:
            ++FixedAttributeSize->NumRefAddrs;
            break;

          case DW_FORM_strp:
          case DW_FORM_GNU_ref_alt:
          case DW_FORM_GNU_strp_alt:
          case DW_FORM_line_strp:
          case DW_FORM_sec_offset:
          case DW_FORM_strp_sup:
          case DW_FORM_ref_sup:
            ++FixedAttributeSize->NumDwarfOffsets;
            break;

          default:
            // Indicate we no longer have a fixed byte size for this
            // abbreviation by clearing the FixedAttributeSize optional value
            // so it doesn't have a value.
            FixedAttributeSize.reset();
            break;
          }
        }
      }
    } else if (A == 0 && F == 0) {
      // We successfully reached the end of this abbreviation declaration
      // since both attribute and form are zero.
      break;
    } else {
      // Attribute and form pairs must either both be non-zero, in which case
      // they are added to the abbreviation declaration, or both be zero to
      // terminate the abbrevation declaration. In this case only one was
      // zero which is an error.
      clear();
      return false;
    }
  }
  return true;
}

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;
}