C++ DWARFDie::find方法代码示例

bool DWARFUnit::parseDWO() {
  if (isDWO)
    return false;
  if (DWO.get())
    return false;
  DWARFDie UnitDie = getUnitDIE();
  if (!UnitDie)
    return false;
  auto DWOFileName = dwarf::toString(UnitDie.find(DW_AT_GNU_dwo_name));
  if (!DWOFileName)
    return false;
  auto CompilationDir = dwarf::toString(UnitDie.find(DW_AT_comp_dir));
  SmallString<16> AbsolutePath;
  if (sys::path::is_relative(*DWOFileName) && CompilationDir &&
      *CompilationDir) {
    sys::path::append(AbsolutePath, *CompilationDir);
  }
  sys::path::append(AbsolutePath, *DWOFileName);
  auto DWOId = getDWOId();
  if (!DWOId)
    return false;
  auto DWOContext = Context.getDWOContext(AbsolutePath);
  if (!DWOContext)
    return false;

  DWARFCompileUnit *DWOCU = DWOContext->getDWOCompileUnitForHash(*DWOId);
  if (!DWOCU)
    return false;
  DWO = std::shared_ptr<DWARFCompileUnit>(std::move(DWOContext), DWOCU);
  // Share .debug_addr and .debug_ranges section with compile unit in .dwo
  DWO->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
  auto DWORangesBase = UnitDie.getRangesBaseAttribute();
  DWO->setRangesSection(RangeSection, DWORangesBase ? *DWORangesBase : 0);
  return true;
}

bool DWARFUnit::parseDWO() {
  if (isDWO)
    return false;
  if (DWO.get())
    return false;
  DWARFDie UnitDie = getUnitDIE();
  if (!UnitDie)
    return false;
  auto DWOFileName = dwarf::toString(UnitDie.find(DW_AT_GNU_dwo_name));
  if (!DWOFileName)
    return false;
  auto CompilationDir = dwarf::toString(UnitDie.find(DW_AT_comp_dir));
  SmallString<16> AbsolutePath;
  if (sys::path::is_relative(*DWOFileName) && CompilationDir &&
      *CompilationDir) {
    sys::path::append(AbsolutePath, *CompilationDir);
  }
  sys::path::append(AbsolutePath, *DWOFileName);
  auto DWOId = getDWOId();
  if (!DWOId)
    return false;
  auto DWOContext = Context.getDWOContext(AbsolutePath);
  if (!DWOContext)
    return false;

  DWARFCompileUnit *DWOCU = DWOContext->getDWOCompileUnitForHash(*DWOId);
  if (!DWOCU)
    return false;
  DWO = std::shared_ptr<DWARFCompileUnit>(std::move(DWOContext), DWOCU);
  // Share .debug_addr and .debug_ranges section with compile unit in .dwo
  DWO->setAddrOffsetSection(AddrOffsetSection, AddrOffsetSectionBase);
  if (getVersion() >= 5) {
    DWO->setRangesSection(&Context.getDWARFObj().getRnglistsDWOSection(), 0);
    DWARFDataExtractor RangesDA(Context.getDWARFObj(), *RangeSection,
                                isLittleEndian, 0);
    if (auto TableOrError = parseRngListTableHeader(RangesDA, RangeSectionBase))
      DWO->RngListTable = TableOrError.get();
    else
      WithColor::error() << "parsing a range list table: "
                         << toString(TableOrError.takeError())
                         << '\n';
    if (DWO->RngListTable)
      DWO->RangeSectionBase = DWO->RngListTable->getHeaderSize();
  } else {
    auto DWORangesBase = UnitDie.getRangesBaseAttribute();
    DWO->setRangesSection(RangeSection, DWORangesBase ? *DWORangesBase : 0);
  }

  return true;
}

Optional<DWARFFormValue>
DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
  std::vector<DWARFDie> Worklist;
  Worklist.push_back(*this);

  // Keep track if DIEs already seen to prevent infinite recursion.
  // Empirically we rarely see a depth of more than 3 when dealing with valid
  // DWARF. This corresponds to following the DW_AT_abstract_origin and
  // DW_AT_specification just once.
  SmallSet<DWARFDie, 3> Seen;
  Seen.insert(*this);

  while (!Worklist.empty()) {
    DWARFDie Die = Worklist.back();
    Worklist.pop_back();

    if (!Die.isValid())
      continue;

    if (auto Value = Die.find(Attrs))
      return Value;

    if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
      if (Seen.insert(D).second)
        Worklist.push_back(D);

    if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_specification))
      if (Seen.insert(D).second)
        Worklist.push_back(D);
  }

  return None;
}

uint16_t CompileUnit::getLanguage() {
  if (!Language) {
    DWARFDie CU = getOrigUnit().getUnitDIE();
    Language = dwarf::toUnsigned(CU.find(dwarf::DW_AT_language), 0);
  }
  return Language;
}

void DwarfVariableFinder::getInfo(const DWARFDie &die) {
  auto tagString = TagString(die.getTag());
  if (tagString.empty()) {
    outs() << format("DW_TAG_Unknown_%x", die.getTag());
  }
  auto formVal = die.find(dwarf::DW_AT_name);
  formVal->dump(outs());
}

llvm::Optional<SectionedAddress> DWARFUnit::getBaseAddress() {
  if (BaseAddr)
    return BaseAddr;

  DWARFDie UnitDie = getUnitDIE();
  Optional<DWARFFormValue> PC = UnitDie.find({DW_AT_low_pc, DW_AT_entry_pc});
  BaseAddr = toSectionedAddress(PC);
  return BaseAddr;
}

size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
  if ((CUDieOnly && !DieArray.empty()) ||
      DieArray.size() > 1)
    return 0; // Already parsed.

  bool HasCUDie = !DieArray.empty();
  extractDIEsToVector(!HasCUDie, !CUDieOnly, DieArray);

  if (DieArray.empty())
    return 0;

  // If CU DIE was just parsed, copy several attribute values from it.
  if (!HasCUDie) {
    DWARFDie UnitDie = getUnitDIE();
    Optional<DWARFFormValue> PC = UnitDie.find({DW_AT_low_pc, DW_AT_entry_pc});
    if (Optional<uint64_t> Addr = toAddress(PC))
        setBaseAddress({*Addr, PC->getSectionIndex()});

    if (!isDWO) {
      assert(AddrOffsetSectionBase == 0);
      assert(RangeSectionBase == 0);
      AddrOffsetSectionBase =
          toSectionOffset(UnitDie.find(DW_AT_GNU_addr_base), 0);
      RangeSectionBase = toSectionOffset(UnitDie.find(DW_AT_rnglists_base), 0);
    }

    // In general, we derive the offset of the unit's contibution to the
    // debug_str_offsets{.dwo} section from the unit DIE's
    // DW_AT_str_offsets_base attribute. In dwp files we add to it the offset
    // we get from the index table.
    StringOffsetSectionBase =
        toSectionOffset(UnitDie.find(DW_AT_str_offsets_base), 0);
    if (IndexEntry)
      if (const auto *C = IndexEntry->getOffset(DW_SECT_STR_OFFSETS))
        StringOffsetSectionBase += C->Offset;

    // Don't fall back to DW_AT_GNU_ranges_base: it should be ignored for
    // skeleton CU DIE, so that DWARF users not aware of it are not broken.
  }

  return DieArray.size();
}

llvm::Optional<BaseAddress> DWARFUnit::getBaseAddress() {
  if (BaseAddr)
    return BaseAddr;

  DWARFDie UnitDie = getUnitDIE();
  Optional<DWARFFormValue> PC = UnitDie.find({DW_AT_low_pc, DW_AT_entry_pc});
  if (Optional<uint64_t> Addr = toAddress(PC))
    BaseAddr = {*Addr, PC->getSectionIndex()};

  return BaseAddr;
}

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

  if (!die.isValid()) {
    return std::make_shared<TypeInfo>("", ~0u);
  }
  auto opSize = die.find(dwarf::DW_AT_byte_size);
  unsigned size = 1;
  if(opSize.hasValue()) {
    size = opSize.getValue().getAsUnsignedConstant().getValue();  
  }

  std::string type_encoding = "";
  raw_string_ostream SS(type_encoding);

  switch (die.getTag()) {
    case dwarf::DW_TAG_base_type: {  
                                    auto opForm = die.find(dwarf::DW_AT_encoding);
                                    auto opEnc = opForm->getAsUnsignedConstant();
                                    assert(opEnc < HANDLE_DW_ATE_SIZE);
                                    SS << HANDLE_DW_ATE[*opEnc];
                                    opForm = die.find(dwarf::DW_AT_name);
                                    opForm->dump(SS);
                                    return std::make_shared<TypeInfo>(SS.str(), size);
                                  }
    case dwarf::DW_TAG_reference_type:
    case dwarf::DW_TAG_rvalue_reference_type:
    case dwarf::DW_TAG_pointer_type: {
                                       auto baseType = getType(die.getAttributeValueAsReferencedDie(dwarf::DW_AT_type));
                                       SS <<  "*" << baseType->getName();
                                       return std::make_shared<TypeInfo>(SS.str(), size);
                                     }
    case dwarf::DW_TAG_array_type: {
                                     auto baseType = getType(die.getAttributeValueAsReferencedDie(dwarf::DW_AT_type));
                                     SS << baseType->getName();
                                     size *= baseType->getSize();

                                     for (auto childDie = die.getFirstChild(); childDie && childDie.getTag(); 
                                         childDie = childDie.getSibling()) {
                                       std::shared_ptr<TypeInfo> rangeInfo = makeType(childDie);
                                       SS << "[";
                                       SS <<  rangeInfo->getName();
                                       SS << "]";
                                       size *= rangeInfo->getSize();
                                     }
                                     return std::make_shared<TypeInfo>(SS.str(), size);
                                   }
    case dwarf::DW_TAG_subrange_type: {
                                        uint64_t count = 0;
                                        auto opCount = die.find(dwarf::DW_AT_count);
                                        if(opCount.hasValue()) {
                                          count = opCount.getValue().getAsUnsignedConstant().getValue();
                                        } else {
                                          opCount = die.find(dwarf::DW_AT_upper_bound);
                                          assert(opCount.hasValue());
                                          count = opCount.getValue().getAsUnsignedConstant().getValue()  +1;
                                        }
                                        return std::make_shared<TypeInfo>(std::to_string(count), count);
                                      }
    case dwarf::DW_TAG_typedef: {
                                  return getType(die.getAttributeValueAsReferencedDie(dwarf::DW_AT_type));
                                }

    case dwarf::DW_TAG_structure_type:
    case dwarf::DW_TAG_class_type:
    case dwarf::DW_TAG_union_type: {
                                     SS << "struct" << dwarf::toString(die.find(dwarf::DW_AT_name), "None");
                                     auto structType = std::make_shared<TypeInfo>(SS.str(), size);

                                     // Add subentries for various pieces of the struct.
                                     for (auto childDie = die.getFirstChild(); childDie && childDie.getTag(); childDie = childDie.getSibling()) {
                                       if (childDie.getTag() != dwarf::DW_TAG_inheritance &&
                                           childDie.getTag() != dwarf::DW_TAG_member) {
                                         continue;
                                       }
                                       uint64_t dataMemOffset = dwarf::toUnsigned(childDie.find(dwarf::DW_AT_data_member_location), ~0U);
                                       structType->getFields().emplace_back(makeType(childDie), dataMemOffset);
                                     }
                                     return structType;
                                   }

    case dwarf::DW_TAG_inheritance:
    case dwarf::DW_TAG_member: {
                                 return getType(die.getAttributeValueAsReferencedDie(dwarf::DW_AT_type));
                               }        

    default: {
               auto tagString = TagString(die.getTag());
               if (tagString.empty()) {
                 llvm::errs() << format("DW_TAG_Unknown_%x", die.getTag());
               }
               die.dump(llvm::errs(), 10);
               return std::make_shared<TypeInfo>("", ~0u);
             }
  }
}

size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
  if ((CUDieOnly && !DieArray.empty()) ||
      DieArray.size() > 1)
    return 0; // Already parsed.

  bool HasCUDie = !DieArray.empty();
  extractDIEsToVector(!HasCUDie, !CUDieOnly, DieArray);

  if (DieArray.empty())
    return 0;

  // If CU DIE was just parsed, copy several attribute values from it.
  if (!HasCUDie) {
    DWARFDie UnitDie = getUnitDIE();
    if (Optional<uint64_t> DWOId = toUnsigned(UnitDie.find(DW_AT_GNU_dwo_id)))
      Header.setDWOId(*DWOId);
    if (!isDWO) {
      assert(AddrOffsetSectionBase == 0);
      assert(RangeSectionBase == 0);
      AddrOffsetSectionBase =
          toSectionOffset(UnitDie.find(DW_AT_GNU_addr_base), 0);
      RangeSectionBase = toSectionOffset(UnitDie.find(DW_AT_rnglists_base), 0);
    }

    // In general, in DWARF v5 and beyond we derive the start of the unit's
    // contribution to the string offsets table from the unit DIE's
    // DW_AT_str_offsets_base attribute. Split DWARF units do not use this
    // attribute, so we assume that there is a contribution to the string
    // offsets table starting at offset 0 of the debug_str_offsets.dwo section.
    // In both cases we need to determine the format of the contribution,
    // which may differ from the unit's format.
    uint64_t StringOffsetsContributionBase =
        isDWO ? 0 : toSectionOffset(UnitDie.find(DW_AT_str_offsets_base), 0);
    auto IndexEntry = Header.getIndexEntry();
    if (IndexEntry)
      if (const auto *C = IndexEntry->getOffset(DW_SECT_STR_OFFSETS))
        StringOffsetsContributionBase += C->Offset;

    DWARFDataExtractor DA(Context.getDWARFObj(), StringOffsetSection,
                          isLittleEndian, 0);
    if (isDWO)
      StringOffsetsTableContribution =
          determineStringOffsetsTableContributionDWO(
              DA, StringOffsetsContributionBase);
    else if (getVersion() >= 5)
      StringOffsetsTableContribution = determineStringOffsetsTableContribution(
          DA, StringOffsetsContributionBase);

    // DWARF v5 uses the .debug_rnglists and .debug_rnglists.dwo sections to
    // describe address ranges.
    if (getVersion() >= 5) {
      if (isDWO)
        setRangesSection(&Context.getDWARFObj().getRnglistsDWOSection(), 0);
      else
        setRangesSection(&Context.getDWARFObj().getRnglistsSection(),
                         toSectionOffset(UnitDie.find(DW_AT_rnglists_base), 0));
      if (RangeSection->Data.size()) {
        // Parse the range list table header. Individual range lists are
        // extracted lazily.
        DWARFDataExtractor RangesDA(Context.getDWARFObj(), *RangeSection,
                                    isLittleEndian, 0);
        if (auto TableOrError =
                parseRngListTableHeader(RangesDA, RangeSectionBase))
          RngListTable = TableOrError.get();
        else
          WithColor::error() << "parsing a range list table: "
                             << toString(TableOrError.takeError())
                             << '\n';

        // In a split dwarf unit, there is no DW_AT_rnglists_base attribute.
        // Adjust RangeSectionBase to point past the table header.
        if (isDWO && RngListTable)
          RangeSectionBase = RngListTable->getHeaderSize();
      }
    }

    // Don't fall back to DW_AT_GNU_ranges_base: it should be ignored for
    // skeleton CU DIE, so that DWARF users not aware of it are not broken.
  }

  return DieArray.size();
}

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);
  WithColor(OS, HighlightColor::Attribute) << formatv("{0}", Attr);

  if (DumpOpts.Verbose || DumpOpts.ShowForm)
    OS << formatv(" [{0}]", 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();
    // For DW_FORM_rnglistx we need to dump the offset separately, since
    // we have only dumped the index so far.
    Optional<DWARFFormValue> Value = Die.find(DW_AT_ranges);
    if (Value && Value->getForm() == DW_FORM_rnglistx)
      if (auto RangeListOffset =
              U->getRnglistOffset(*Value->getAsSectionOffset())) {
        DWARFFormValue FV(dwarf::DW_FORM_sec_offset);
        FV.setUValue(*RangeListOffset);
        FV.dump(OS, DumpOpts);
      }
    dumpRanges(Obj, OS, Die.getAddressRanges(), U->getAddressByteSize(),
               sizeof(BaseIndent) + Indent + 4, DumpOpts);
  }

  OS << ")\n";
}

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;
    }
//.........这里部分代码省略.........