C++ DWARFDie::getOffset方法代码示例

DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End) :
    Die(D), AttrValue(0), Index(0) {
  auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
  assert(AbbrDecl && "Must have abbreviation declaration");
  if (End) {
    // This is the end iterator so we set the index to the attribute count.
    Index = AbbrDecl->getNumAttributes();
  } else {
    // This is the begin iterator so we extract the value for this->Index.
    AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
    updateForIndex(*AbbrDecl, 0);
  }
}

std::shared_ptr<TypeInfo> DwarfVariableFinder::getType(const DWARFDie &die) {

  if (!die.isValid()) {
    assert(0);
    return std::make_shared<TypeInfo>("", ~0u);
  }

  auto die_offset = die.getOffset();  
  if(typeDict.count(die_offset)) {
    return typeDict[die_offset];
  }

  auto result = makeType(die);
  typeDict[die_offset] = result;
  return result;
}

unsigned DWARFVerifier::verifyDebugInfoForm(const DWARFDie &Die,
                                            DWARFAttribute &AttrValue) {
  const DWARFObject &DObj = DCtx.getDWARFObj();
  unsigned NumErrors = 0;
  const auto Form = AttrValue.Value.getForm();
  switch (Form) {
  case DW_FORM_ref1:
  case DW_FORM_ref2:
  case DW_FORM_ref4:
  case DW_FORM_ref8:
  case DW_FORM_ref_udata: {
    // Verify all CU relative references are valid CU offsets.
    Optional<uint64_t> RefVal = AttrValue.Value.getAsReference();
    assert(RefVal);
    if (RefVal) {
      auto DieCU = Die.getDwarfUnit();
      auto CUSize = DieCU->getNextUnitOffset() - DieCU->getOffset();
      auto CUOffset = AttrValue.Value.getRawUValue();
      if (CUOffset >= CUSize) {
        ++NumErrors;
        error() << FormEncodingString(Form) << " CU offset "
                << format("0x%08" PRIx64, CUOffset)
                << " is invalid (must be less than CU size of "
                << format("0x%08" PRIx32, CUSize) << "):\n";
        Die.dump(OS, 0, DumpOpts);
        OS << "\n";
      } else {
        // Valid reference, but we will verify it points to an actual
        // DIE later.
        ReferenceToDIEOffsets[*RefVal].insert(Die.getOffset());
      }
    }
    break;
  }
  case DW_FORM_ref_addr: {
    // Verify all absolute DIE references have valid offsets in the
    // .debug_info section.
    Optional<uint64_t> RefVal = AttrValue.Value.getAsReference();
    assert(RefVal);
    if (RefVal) {
      if (*RefVal >= DObj.getInfoSection().Data.size()) {
        ++NumErrors;
        error() << "DW_FORM_ref_addr offset beyond .debug_info "
                   "bounds:\n";
        Die.dump(OS, 0, DumpOpts);
        OS << "\n";
      } else {
        // Valid reference, but we will verify it points to an actual
        // DIE later.
        ReferenceToDIEOffsets[*RefVal].insert(Die.getOffset());
      }
    }
    break;
  }
  case DW_FORM_strp: {
    auto SecOffset = AttrValue.Value.getAsSectionOffset();
    assert(SecOffset); // DW_FORM_strp is a section offset.
    if (SecOffset && *SecOffset >= DObj.getStringSection().size()) {
      ++NumErrors;
      error() << "DW_FORM_strp offset beyond .debug_str bounds:\n";
      Die.dump(OS, 0, DumpOpts);
      OS << "\n";
    }
    break;
  }
  default:
    break;
  }
  return NumErrors;
}

unsigned DWARFVerifier::verifyNameIndexCompleteness(
    const DWARFDie &Die, const DWARFDebugNames::NameIndex &NI) {

  // First check, if the Die should be indexed. The code follows the DWARF v5
  // wording as closely as possible.

  // "All non-defining declarations (that is, debugging information entries
  // with a DW_AT_declaration attribute) are excluded."
  if (Die.find(DW_AT_declaration))
    return 0;

  // "DW_TAG_namespace debugging information entries without a DW_AT_name
  // attribute are included with the name “(anonymous namespace)”.
  // All other debugging information entries without a DW_AT_name attribute
  // are excluded."
  // "If a subprogram or inlined subroutine is included, and has a
  // DW_AT_linkage_name attribute, there will be an additional index entry for
  // the linkage name."
  auto IncludeLinkageName = Die.getTag() == DW_TAG_subprogram ||
                            Die.getTag() == DW_TAG_inlined_subroutine;
  auto EntryNames = getNames(Die, IncludeLinkageName);
  if (EntryNames.empty())
    return 0;

  // We deviate from the specification here, which says:
  // "The name index must contain an entry for each debugging information entry
  // that defines a named subprogram, label, variable, type, or namespace,
  // subject to ..."
  // Instead whitelisting all TAGs representing a "type" or a "subprogram", to
  // make sure we catch any missing items, we instead blacklist all TAGs that we
  // know shouldn't be indexed.
  switch (Die.getTag()) {
  // Compile units and modules have names but shouldn't be indexed.
  case DW_TAG_compile_unit:
  case DW_TAG_module:
    return 0;

  // Function and template parameters are not globally visible, so we shouldn't
  // index them.
  case DW_TAG_formal_parameter:
  case DW_TAG_template_value_parameter:
  case DW_TAG_template_type_parameter:
  case DW_TAG_GNU_template_parameter_pack:
  case DW_TAG_GNU_template_template_param:
    return 0;

  // Object members aren't globally visible.
  case DW_TAG_member:
    return 0;

  // According to a strict reading of the specification, enumerators should not
  // be indexed (and LLVM currently does not do that). However, this causes
  // problems for the debuggers, so we may need to reconsider this.
  case DW_TAG_enumerator:
    return 0;

  // Imported declarations should not be indexed according to the specification
  // and LLVM currently does not do that.
  case DW_TAG_imported_declaration:
    return 0;

  // "DW_TAG_subprogram, DW_TAG_inlined_subroutine, and DW_TAG_label debugging
  // information entries without an address attribute (DW_AT_low_pc,
  // DW_AT_high_pc, DW_AT_ranges, or DW_AT_entry_pc) are excluded."
  case DW_TAG_subprogram:
  case DW_TAG_inlined_subroutine:
  case DW_TAG_label:
    if (Die.findRecursively(
            {DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_entry_pc}))
      break;
    return 0;

  // "DW_TAG_variable debugging information entries with a DW_AT_location
  // attribute that includes a DW_OP_addr or DW_OP_form_tls_address operator are
  // included; otherwise, they are excluded."
  //
  // LLVM extension: We also add DW_OP_GNU_push_tls_address to this list.
  case DW_TAG_variable:
    if (isVariableIndexable(Die, DCtx))
      break;
    return 0;

  default:
    break;
  }

  // Now we know that our Die should be present in the Index. Let's check if
  // that's the case.
  unsigned NumErrors = 0;
  uint64_t DieUnitOffset = Die.getOffset() - Die.getDwarfUnit()->getOffset();
  for (StringRef Name : EntryNames) {
    if (none_of(NI.equal_range(Name), [&](const DWARFDebugNames::Entry &E) {
          return E.getDIEUnitOffset() == DieUnitOffset;
        })) {
      error() << formatv("Name Index @ {0:x}: Entry for DIE @ {1:x} ({2}) with "
                         "name {3} missing.\n",
                         NI.getUnitOffset(), Die.getOffset(), Die.getTag(),
                         Name);
      ++NumErrors;
    }
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