C++ DWARFUnit类代码示例

bool DWARFUnit::parseDWO() {
  if (DWO.get() != 0)
    return false;
  extractDIEsIfNeeded(true);
  if (DieArray.empty())
    return false;
  const char *DWOFileName =
      DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, 0);
  if (DWOFileName == 0)
    return false;
  const char *CompilationDir =
      DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, 0);
  SmallString<16> AbsolutePath;
  if (sys::path::is_relative(DWOFileName) && CompilationDir != 0) {
    sys::path::append(AbsolutePath, CompilationDir);
  }
  sys::path::append(AbsolutePath, DWOFileName);
  ErrorOr<object::ObjectFile *> DWOFile =
      object::ObjectFile::createObjectFile(AbsolutePath);
  if (!DWOFile)
    return false;
  // Reset DWOHolder.
  DWO.reset(new DWOHolder(DWOFile.get()));
  DWARFUnit *DWOCU = DWO->getUnit();
  // Verify that compile unit in .dwo file is valid.
  if (DWOCU == 0 || DWOCU->getDWOId() != getDWOId()) {
    DWO.reset();
    return false;
  }
  // Share .debug_addr and .debug_ranges section with compile unit in .dwo
  DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
  DWOCU->setRangesSection(RangeSection, RangeSectionBase);
  return true;
}

Optional<DWARFFormValue> DWARFAbbreviationDeclaration::getAttributeValue(
    const uint32_t DIEOffset, const dwarf::Attribute Attr,
    const DWARFUnit &U) const {
  Optional<uint32_t> MatchAttrIndex = findAttributeIndex(Attr);
  if (!MatchAttrIndex)
    return None;

  auto DebugInfoData = U.getDebugInfoExtractor();

  // Add the byte size of ULEB that for the abbrev Code so we can start
  // skipping the attribute data.
  uint32_t Offset = DIEOffset + CodeByteSize;
  uint32_t AttrIndex = 0;
  for (const auto &Spec : AttributeSpecs) {
    if (*MatchAttrIndex == AttrIndex) {
      // We have arrived at the attribute to extract, extract if from Offset.
      DWARFFormValue FormValue(Spec.Form);
      if (Spec.isImplicitConst()) {
        FormValue.setSValue(*Spec.ByteSizeOrValue);
        return FormValue;
      }
      if (FormValue.extractValue(DebugInfoData, &Offset, &U))
        return FormValue;
    }
    // March Offset along until we get to the attribute we want.
    if (auto FixedSize = Spec.getByteSize(U))
      Offset += *FixedSize;
    else
      DWARFFormValue::skipValue(Spec.Form, DebugInfoData, &Offset,
                                U.getFormParams());
    ++AttrIndex;
  }
  return None;
}

static bool isVariableIndexable(const DWARFDie &Die, DWARFContext &DCtx) {
  Optional<DWARFFormValue> Location = Die.findRecursively(DW_AT_location);
  if (!Location)
    return false;

  auto ContainsInterestingOperators = [&](StringRef D) {
    DWARFUnit *U = Die.getDwarfUnit();
    DataExtractor Data(D, DCtx.isLittleEndian(), U->getAddressByteSize());
    DWARFExpression Expression(Data, U->getVersion(), U->getAddressByteSize());
    return any_of(Expression, [](DWARFExpression::Operation &Op) {
      return !Op.isError() && (Op.getCode() == DW_OP_addr ||
                               Op.getCode() == DW_OP_form_tls_address ||
                               Op.getCode() == DW_OP_GNU_push_tls_address);
    });
  };

  if (Optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
    // Inlined location.
    if (ContainsInterestingOperators(toStringRef(*Expr)))
      return true;
  } else if (Optional<uint64_t> Offset = Location->getAsSectionOffset()) {
    // Location list.
    if (const DWARFDebugLoc *DebugLoc = DCtx.getDebugLoc()) {
      if (const DWARFDebugLoc::LocationList *LocList =
              DebugLoc->getLocationListAtOffset(*Offset)) {
        if (any_of(LocList->Entries, [&](const DWARFDebugLoc::Entry &E) {
              return ContainsInterestingOperators({E.Loc.data(), E.Loc.size()});
            }))
          return true;
      }
    }
  }
  return false;
}

bool DWARFUnit::parseDWO() {
  if (DWO.get())
    return false;
  extractDIEsIfNeeded(true);
  if (DieArray.empty())
    return false;
  const char *DWOFileName =
      DieArray[0].getAttributeValueAsString(this, DW_AT_GNU_dwo_name, nullptr);
  if (!DWOFileName)
    return false;
  const char *CompilationDir =
      DieArray[0].getAttributeValueAsString(this, DW_AT_comp_dir, nullptr);
  SmallString<16> AbsolutePath;
  if (sys::path::is_relative(DWOFileName) && CompilationDir != nullptr) {
    sys::path::append(AbsolutePath, CompilationDir);
  }
  sys::path::append(AbsolutePath, DWOFileName);
  DWO = llvm::make_unique<DWOHolder>(AbsolutePath);
  DWARFUnit *DWOCU = DWO->getUnit();
  // Verify that compile unit in .dwo file is valid.
  if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {
    DWO.reset();
    return false;
  }
  // Share .debug_addr and .debug_ranges section with compile unit in .dwo
  DWOCU->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
  uint32_t DWORangesBase = DieArray[0].getRangesBaseAttribute(this, 0);
  DWOCU->setRangesSection(RangeSection, DWORangesBase);
  return true;
}

DWARFUnit *DWARFDebugLine::SectionParser::prepareToParse(uint32_t Offset) {
  DWARFUnit *U = nullptr;
  auto It = LineToUnit.find(Offset);
  if (It != LineToUnit.end())
    U = It->second;
  DebugLineData.setAddressSize(U ? U->getAddressByteSize() : 0);
  return U;
}

unsigned DWARFVerifier::verifyDebugInfoAttribute(const DWARFDie &Die,
                                                 DWARFAttribute &AttrValue) {
  unsigned NumErrors = 0;
  auto ReportError = [&](const Twine &TitleMsg) {
    ++NumErrors;
    error() << TitleMsg << '\n';
    Die.dump(OS, 0, DumpOpts);
    OS << "\n";
  };

  const DWARFObject &DObj = DCtx.getDWARFObj();
  const auto Attr = AttrValue.Attr;
  switch (Attr) {
  case DW_AT_ranges:
    // Make sure the offset in the DW_AT_ranges attribute is valid.
    if (auto SectionOffset = AttrValue.Value.getAsSectionOffset()) {
      if (*SectionOffset >= DObj.getRangeSection().Data.size())
        ReportError("DW_AT_ranges offset is beyond .debug_ranges bounds:");
      break;
    }
    ReportError("DIE has invalid DW_AT_ranges encoding:");
    break;
  case DW_AT_stmt_list:
    // Make sure the offset in the DW_AT_stmt_list attribute is valid.
    if (auto SectionOffset = AttrValue.Value.getAsSectionOffset()) {
      if (*SectionOffset >= DObj.getLineSection().Data.size())
        ReportError("DW_AT_stmt_list offset is beyond .debug_line bounds: " +
                    llvm::formatv("{0:x8}", *SectionOffset));
      break;
    }
    ReportError("DIE has invalid DW_AT_stmt_list encoding:");
    break;
  case DW_AT_location: {
    Optional<ArrayRef<uint8_t>> Expr = AttrValue.Value.getAsBlock();
    if (!Expr) {
      ReportError("DIE has invalid DW_AT_location encoding:");
      break;
    }

    DWARFUnit *U = Die.getDwarfUnit();
    DataExtractor Data(
        StringRef(reinterpret_cast<const char *>(Expr->data()), Expr->size()),
        DCtx.isLittleEndian(), 0);
    DWARFExpression Expression(Data, U->getVersion(), U->getAddressByteSize());
    bool Error = llvm::any_of(Expression, [](DWARFExpression::Operation &Op) {
      return Op.isError();
    });
    if (Error)
      ReportError("DIE contains invalid DWARF expression:");
    break;
  }

  default:
    break;
  }
  return NumErrors;
}

size_t DWARFAbbreviationDeclaration::FixedSizeInfo::getByteSize(
    const DWARFUnit &U) const {
  size_t ByteSize = NumBytes;
  if (NumAddrs)
    ByteSize += NumAddrs * U.getAddressByteSize();
  if (NumRefAddrs)
    ByteSize += NumRefAddrs * U.getRefAddrByteSize();
  if (NumDwarfOffsets)
    ByteSize += NumDwarfOffsets * U.getDwarfOffsetByteSize();
  return ByteSize;
}

bool DWARFVerifier::verifyUnitContents(DWARFUnit Unit) {
  uint32_t NumUnitErrors = 0;
  unsigned NumDies = Unit.getNumDIEs();
  for (unsigned I = 0; I < NumDies; ++I) {
    auto Die = Unit.getDIEAtIndex(I);
    if (Die.getTag() == DW_TAG_null)
      continue;
    NumUnitErrors += verifyDieRanges(Die);
    for (auto AttrValue : Die.attributes()) {
      NumUnitErrors += verifyDebugInfoAttribute(Die, AttrValue);
      NumUnitErrors += verifyDebugInfoForm(Die, AttrValue);
    }
  }
  return NumUnitErrors == 0;
}

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.getFormParams())) {
      // We failed to skip this attribute's value, restore the original offset
      // and return the failure status.
      *OffsetPtr = Offset;
      return false;
    }
  }
  return true;
}

bool DWARFVerifier::verifyUnitContents(DWARFUnit Unit, uint8_t UnitType) {
  uint32_t NumUnitErrors = 0;
  unsigned NumDies = Unit.getNumDIEs();
  for (unsigned I = 0; I < NumDies; ++I) {
    auto Die = Unit.getDIEAtIndex(I);
    if (Die.getTag() == DW_TAG_null)
      continue;
    for (auto AttrValue : Die.attributes()) {
      NumUnitErrors += verifyDebugInfoAttribute(Die, AttrValue);
      NumUnitErrors += verifyDebugInfoForm(Die, AttrValue);
    }
  }

  DWARFDie Die = Unit.getUnitDIE(/* ExtractUnitDIEOnly = */ false);
  if (!Die) {
    error() << "Compilation unit without DIE.\n";
    NumUnitErrors++;
    return NumUnitErrors == 0;
  }

  if (!dwarf::isUnitType(Die.getTag())) {
    error() << "Compilation unit root DIE is not a unit DIE: "
            << dwarf::TagString(Die.getTag()) << ".\n";
    NumUnitErrors++;
  }

  if (UnitType != 0 &&
      !DWARFUnit::isMatchingUnitTypeAndTag(UnitType, Die.getTag())) {
    error() << "Compilation unit type (" << dwarf::UnitTypeString(UnitType)
            << ") and root DIE (" << dwarf::TagString(Die.getTag())
            << ") do not match.\n";
    NumUnitErrors++;
  }

  DieRangeInfo RI;
  NumUnitErrors += verifyDieRanges(Die, RI);

  return NumUnitErrors == 0;
}

Optional<int64_t> DWARFAbbreviationDeclaration::AttributeSpec::getByteSize(
    const DWARFUnit &U) const {
  if (isImplicitConst())
    return 0;
  if (ByteSizeOrValue)
    return ByteSizeOrValue;
  Optional<int64_t> S;
  auto FixedByteSize =
      DWARFFormValue::getFixedByteSize(Form, U.getFormParams());
  if (FixedByteSize)
    S = *FixedByteSize;
  return S;
}

void ManualDWARFIndex::IndexUnit(DWARFUnit &unit, IndexSet &set) {
  assert(!unit.GetSymbolFileDWARF()->GetBaseCompileUnit() &&
      "DWARFUnit associated with .dwo or .dwp should not be indexed directly");

  Log *log = LogChannelDWARF::GetLogIfAll(DWARF_LOG_LOOKUPS);

  if (log) {
    m_module.LogMessage(
        log, "ManualDWARFIndex::IndexUnit for compile unit at .debug_info[0x%8.8x]",
        unit.GetOffset());
  }

  const LanguageType cu_language = unit.GetLanguageType();
  DWARFFormValue::FixedFormSizes fixed_form_sizes = unit.GetFixedFormSizes();

  IndexUnitImpl(unit, cu_language, fixed_form_sizes, unit.GetOffset(), set);

  SymbolFileDWARFDwo *dwo_symbol_file = unit.GetDwoSymbolFile();
  if (dwo_symbol_file && dwo_symbol_file->GetCompileUnit()) {
    IndexUnitImpl(*dwo_symbol_file->GetCompileUnit(), cu_language,
                  fixed_form_sizes, unit.GetOffset(), set);
  }
}

bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U,
                                             uint32_t *OffsetPtr) {
  DataExtractor DebugInfoData = U.getDebugInfoExtractor();
  const uint32_t UEndOffset = U.getNextUnitOffset();
  return extractFast(U, OffsetPtr, DebugInfoData, UEndOffset, 0);
}

unsigned DWARFVerifier::verifyDebugInfoAttribute(const DWARFDie &Die,
                                                 DWARFAttribute &AttrValue) {
  unsigned NumErrors = 0;
  auto ReportError = [&](const Twine &TitleMsg) {
    ++NumErrors;
    error() << TitleMsg << '\n';
    Die.dump(OS, 0, DumpOpts);
    OS << "\n";
  };

  const DWARFObject &DObj = DCtx.getDWARFObj();
  const auto Attr = AttrValue.Attr;
  switch (Attr) {
  case DW_AT_ranges:
    // Make sure the offset in the DW_AT_ranges attribute is valid.
    if (auto SectionOffset = AttrValue.Value.getAsSectionOffset()) {
      if (*SectionOffset >= DObj.getRangeSection().Data.size())
        ReportError("DW_AT_ranges offset is beyond .debug_ranges bounds:");
      break;
    }
    ReportError("DIE has invalid DW_AT_ranges encoding:");
    break;
  case DW_AT_stmt_list:
    // Make sure the offset in the DW_AT_stmt_list attribute is valid.
    if (auto SectionOffset = AttrValue.Value.getAsSectionOffset()) {
      if (*SectionOffset >= DObj.getLineSection().Data.size())
        ReportError("DW_AT_stmt_list offset is beyond .debug_line bounds: " +
                    llvm::formatv("{0:x8}", *SectionOffset));
      break;
    }
    ReportError("DIE has invalid DW_AT_stmt_list encoding:");
    break;
  case DW_AT_location: {
    auto VerifyLocation = [&](StringRef D) {
      DWARFUnit *U = Die.getDwarfUnit();
      DataExtractor Data(D, DCtx.isLittleEndian(), 0);
      DWARFExpression Expression(Data, U->getVersion(),
                                 U->getAddressByteSize());
      bool Error = llvm::any_of(Expression, [](DWARFExpression::Operation &Op) {
        return Op.isError();
      });
      if (Error)
        ReportError("DIE contains invalid DWARF expression:");
    };
    if (Optional<ArrayRef<uint8_t>> Expr = AttrValue.Value.getAsBlock()) {
      // Verify inlined location.
      VerifyLocation(llvm::toStringRef(*Expr));
    } else if (auto LocOffset = AttrValue.Value.getAsUnsignedConstant()) {
      // Verify location list.
      if (auto DebugLoc = DCtx.getDebugLoc())
        if (auto LocList = DebugLoc->getLocationListAtOffset(*LocOffset))
          for (const auto &Entry : LocList->Entries)
            VerifyLocation({Entry.Loc.data(), Entry.Loc.size()});
    }
    break;
  }

  default:
    break;
  }
  return NumErrors;
}

void ManualDWARFIndex::IndexUnitImpl(
    DWARFUnit &unit, const LanguageType cu_language,
    const DWARFFormValue::FixedFormSizes &fixed_form_sizes,
    const dw_offset_t cu_offset, IndexSet &set) {
  for (const DWARFDebugInfoEntry &die : unit.dies()) {
    const dw_tag_t tag = die.Tag();

    switch (tag) {
    case DW_TAG_array_type:
    case DW_TAG_base_type:
    case DW_TAG_class_type:
    case DW_TAG_constant:
    case DW_TAG_enumeration_type:
    case DW_TAG_inlined_subroutine:
    case DW_TAG_namespace:
    case DW_TAG_string_type:
    case DW_TAG_structure_type:
    case DW_TAG_subprogram:
    case DW_TAG_subroutine_type:
    case DW_TAG_typedef:
    case DW_TAG_union_type:
    case DW_TAG_unspecified_type:
    case DW_TAG_variable:
      break;

    default:
      continue;
    }

    DWARFAttributes attributes;
    const char *name = NULL;
    const char *mangled_cstr = NULL;
    bool is_declaration = false;
    // bool is_artificial = false;
    bool has_address = false;
    bool has_location_or_const_value = false;
    bool is_global_or_static_variable = false;

    DWARFFormValue specification_die_form;
    const size_t num_attributes =
        die.GetAttributes(&unit, fixed_form_sizes, attributes);
    if (num_attributes > 0) {
      for (uint32_t i = 0; i < num_attributes; ++i) {
        dw_attr_t attr = attributes.AttributeAtIndex(i);
        DWARFFormValue form_value;
        switch (attr) {
        case DW_AT_name:
          if (attributes.ExtractFormValueAtIndex(i, form_value))
            name = form_value.AsCString();
          break;

        case DW_AT_declaration:
          if (attributes.ExtractFormValueAtIndex(i, form_value))
            is_declaration = form_value.Unsigned() != 0;
          break;

        //                case DW_AT_artificial:
        //                    if (attributes.ExtractFormValueAtIndex(i,
        //                    form_value))
        //                        is_artificial = form_value.Unsigned() != 0;
        //                    break;

        case DW_AT_MIPS_linkage_name:
        case DW_AT_linkage_name:
          if (attributes.ExtractFormValueAtIndex(i, form_value))
            mangled_cstr = form_value.AsCString();
          break;

        case DW_AT_low_pc:
        case DW_AT_high_pc:
        case DW_AT_ranges:
          has_address = true;
          break;

        case DW_AT_entry_pc:
          has_address = true;
          break;

        case DW_AT_location:
        case DW_AT_const_value:
          has_location_or_const_value = true;
          if (tag == DW_TAG_variable) {
            const DWARFDebugInfoEntry *parent_die = die.GetParent();
            while (parent_die != NULL) {
              switch (parent_die->Tag()) {
              case DW_TAG_subprogram:
              case DW_TAG_lexical_block:
              case DW_TAG_inlined_subroutine:
                // Even if this is a function level static, we don't add it. We
                // could theoretically add these if we wanted to by
                // introspecting into the DW_AT_location and seeing if the
                // location describes a hard coded address, but we don't want
                // the performance penalty of that right now.
                is_global_or_static_variable = false;
                // if (attributes.ExtractFormValueAtIndex(dwarf, i,
                //                                        form_value)) {
                //   // If we have valid block data, then we have location
                //   // expression bytesthat are fixed (not a location list).
                //   const uint8_t *block_data = form_value.BlockData();
                //   if (block_data) {
//.........这里部分代码省略.........