C++ DWARFUnit::getFormParams方法代码示例

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;
}

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;
}

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;
}

static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
                          uint32_t *OffsetPtr, dwarf::Attribute Attr,
                          dwarf::Form Form, unsigned Indent,
                          DIDumpOptions DumpOpts) {
  if (!Die.isValid())
    return;
  const char BaseIndent[] = "            ";
  OS << BaseIndent;
  OS.indent(Indent + 2);
  auto attrString = AttributeString(Attr);
  if (!attrString.empty())
    WithColor(OS, HighlightColor::Attribute) << attrString;
  else
    WithColor(OS, HighlightColor::Attribute).get()
        << format("DW_AT_Unknown_%x", Attr);

  if (DumpOpts.Verbose || DumpOpts.ShowForm) {
    auto formString = FormEncodingString(Form);
    if (!formString.empty())
      OS << " [" << formString << ']';
    else
      OS << format(" [DW_FORM_Unknown_%x]", Form);
  }

  DWARFUnit *U = Die.getDwarfUnit();
  DWARFFormValue formValue(Form);

  if (!formValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr,
                              U->getFormParams(), U))
    return;

  OS << "\t(";

  StringRef Name;
  std::string File;
  auto Color = HighlightColor::Enumerator;
  if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
    Color = HighlightColor::String;
    if (const auto *LT = U->getContext().getLineTableForUnit(U))
      if (LT->getFileNameByIndex(
              formValue.getAsUnsignedConstant().getValue(),
              U->getCompilationDir(),
              DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
        File = '"' + File + '"';
        Name = File;
      }
  } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
    Name = AttributeValueString(Attr, *Val);

  if (!Name.empty())
    WithColor(OS, Color) << Name;
  else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
    OS << *formValue.getAsUnsignedConstant();
  else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
           formValue.getAsUnsignedConstant()) {
    if (DumpOpts.ShowAddresses) {
      // Print the actual address rather than the offset.
      uint64_t LowPC, HighPC, Index;
      if (Die.getLowAndHighPC(LowPC, HighPC, Index))
        OS << format("0x%016" PRIx64, HighPC);
      else
        formValue.dump(OS, DumpOpts);
    }
  } else if (Attr == DW_AT_location || Attr == DW_AT_frame_base ||
             Attr == DW_AT_data_member_location ||
             Attr == DW_AT_GNU_call_site_value)
    dumpLocation(OS, formValue, U, sizeof(BaseIndent) + Indent + 4, DumpOpts);
  else
    formValue.dump(OS, DumpOpts);

  // We have dumped the attribute raw value. For some attributes
  // having both the raw value and the pretty-printed value is
  // interesting. These attributes are handled below.
  if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
    if (const char *Name = Die.getAttributeValueAsReferencedDie(Attr).getName(
            DINameKind::LinkageName))
      OS << " \"" << Name << '\"';
  } else if (Attr == DW_AT_type) {
    OS << " \"";
    dumpTypeName(OS, Die);
    OS << '"';
  } else if (Attr == DW_AT_APPLE_property_attribute) {
    if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
      dumpApplePropertyAttribute(OS, *OptVal);
  } else if (Attr == DW_AT_ranges) {
    const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
    dumpRanges(Obj, OS, Die.getAddressRanges(), U->getAddressByteSize(),
               sizeof(BaseIndent) + Indent + 4, DumpOpts);
  }

  OS << ")\n";
}