DwarfDebug.cpp

// Emit visible names into a hashed accelerator table section.
void DwarfDebug::emitAccelNames() {
  DwarfAccelTable AT(DwarfAccelTable::Atom(DwarfAccelTable::eAtomTypeDIEOffset,
                                           dwarf::DW_FORM_data4));
  for (DenseMap<const MDNode *, CompileUnit *>::iterator I = CUMap.begin(),
         E = CUMap.end(); I != E; ++I) {
    CompileUnit *TheCU = I->second;
    const StringMap<std::vector<DIE*> > &Names = TheCU->getAccelNames();
    for (StringMap<std::vector<DIE*> >::const_iterator
           GI = Names.begin(), GE = Names.end(); GI != GE; ++GI) {
      const char *Name = GI->getKeyData();
      const std::vector<DIE *> &Entities = GI->second;
      for (std::vector<DIE *>::const_iterator DI = Entities.begin(),
             DE = Entities.end(); DI != DE; ++DI)
        AT.AddName(Name, (*DI));
    }
  }

  AT.FinalizeTable(Asm, "Names");
  Asm->OutStreamer.SwitchSection(
    Asm->getObjFileLowering().getDwarfAccelNamesSection());
  MCSymbol *SectionBegin = Asm->GetTempSymbol("names_begin");
  Asm->OutStreamer.EmitLabel(SectionBegin);

  // Emit the full data.
  AT.Emit(Asm, SectionBegin, &InfoHolder);
}

// Emit objective C classes and categories into a hashed accelerator table
// section.
void DwarfDebug::emitAccelObjC() {
  DwarfAccelTable AT(DwarfAccelTable::Atom(DwarfAccelTable::eAtomTypeDIEOffset,
                                           dwarf::DW_FORM_data4));
  for (DenseMap<const MDNode *, CompileUnit *>::iterator I = CUMap.begin(),
         E = CUMap.end(); I != E; ++I) {
    CompileUnit *TheCU = I->second;
    const StringMap<std::vector<DIE*> > &Names = TheCU->getAccelObjC();
    for (StringMap<std::vector<DIE*> >::const_iterator
           GI = Names.begin(), GE = Names.end(); GI != GE; ++GI) {
      const char *Name = GI->getKeyData();
      const std::vector<DIE *> &Entities = GI->second;
      for (std::vector<DIE *>::const_iterator DI = Entities.begin(),
             DE = Entities.end(); DI != DE; ++DI)
        AT.AddName(Name, (*DI));
    }
  }

  AT.FinalizeTable(Asm, "ObjC");
  Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering()
                                 .getDwarfAccelObjCSection());
  MCSymbol *SectionBegin = Asm->GetTempSymbol("objc_begin");
  Asm->OutStreamer.EmitLabel(SectionBegin);

  // Emit the full data.
  AT.Emit(Asm, SectionBegin, &InfoHolder);
}

// Emit namespace dies into a hashed accelerator table.
void DwarfDebug::emitAccelNamespaces() {
  DwarfAccelTable AT(DwarfAccelTable::Atom(DwarfAccelTable::eAtomTypeDIEOffset,
                                           dwarf::DW_FORM_data4));
  for (DenseMap<const MDNode *, CompileUnit *>::iterator I = CUMap.begin(),
         E = CUMap.end(); I != E; ++I) {
    CompileUnit *TheCU = I->second;
    const StringMap<std::vector<DIE*> > &Names = TheCU->getAccelNamespace();
    for (StringMap<std::vector<DIE*> >::const_iterator
           GI = Names.begin(), GE = Names.end(); GI != GE; ++GI) {
      const char *Name = GI->getKeyData();
      const std::vector<DIE *> &Entities = GI->second;
      for (std::vector<DIE *>::const_iterator DI = Entities.begin(),
             DE = Entities.end(); DI != DE; ++DI)
        AT.AddName(Name, (*DI));
    }
  }

  AT.FinalizeTable(Asm, "namespac");
  Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering()
                                 .getDwarfAccelNamespaceSection());
  MCSymbol *SectionBegin = Asm->GetTempSymbol("namespac_begin");
  Asm->OutStreamer.EmitLabel(SectionBegin);

  // Emit the full data.
  AT.Emit(Asm, SectionBegin, &InfoHolder);
}

// Emit type dies into a hashed accelerator table.
void DwarfDebug::emitAccelTypes() {
  std::vector<DwarfAccelTable::Atom> Atoms;
  Atoms.push_back(DwarfAccelTable::Atom(DwarfAccelTable::eAtomTypeDIEOffset,
                                        dwarf::DW_FORM_data4));
  Atoms.push_back(DwarfAccelTable::Atom(DwarfAccelTable::eAtomTypeTag,
                                        dwarf::DW_FORM_data2));
  Atoms.push_back(DwarfAccelTable::Atom(DwarfAccelTable::eAtomTypeTypeFlags,
                                        dwarf::DW_FORM_data1));
  DwarfAccelTable AT(Atoms);
  for (DenseMap<const MDNode *, CompileUnit *>::iterator I = CUMap.begin(),
         E = CUMap.end(); I != E; ++I) {
    CompileUnit *TheCU = I->second;
    const StringMap<std::vector<std::pair<DIE*, unsigned > > > &Names
      = TheCU->getAccelTypes();
    for (StringMap<std::vector<std::pair<DIE*, unsigned> > >::const_iterator
           GI = Names.begin(), GE = Names.end(); GI != GE; ++GI) {
      const char *Name = GI->getKeyData();
      const std::vector<std::pair<DIE *, unsigned> > &Entities = GI->second;
      for (std::vector<std::pair<DIE *, unsigned> >::const_iterator DI
             = Entities.begin(), DE = Entities.end(); DI !=DE; ++DI)
        AT.AddName(Name, (*DI).first, (*DI).second);
    }
  }

  AT.FinalizeTable(Asm, "types");
  Asm->OutStreamer.SwitchSection(Asm->getObjFileLowering()
                                 .getDwarfAccelTypesSection());
  MCSymbol *SectionBegin = Asm->GetTempSymbol("types_begin");
  Asm->OutStreamer.EmitLabel(SectionBegin);

  // Emit the full data.
  AT.Emit(Asm, SectionBegin, &InfoHolder);
}

void DwarfDebug::emitDebugPubTypes() {
  for (DenseMap<const MDNode *, CompileUnit *>::iterator I = CUMap.begin(),
         E = CUMap.end(); I != E; ++I) {
    CompileUnit *TheCU = I->second;
    // Start the dwarf pubtypes section.
    Asm->OutStreamer.SwitchSection(
      Asm->getObjFileLowering().getDwarfPubTypesSection());
    Asm->OutStreamer.AddComment("Length of Public Types Info");
    Asm->EmitLabelDifference(
      Asm->GetTempSymbol("pubtypes_end", TheCU->getUniqueID()),
      Asm->GetTempSymbol("pubtypes_begin", TheCU->getUniqueID()), 4);

    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("pubtypes_begin",
                                                  TheCU->getUniqueID()));

    if (Asm->isVerbose()) Asm->OutStreamer.AddComment("DWARF Version");
    Asm->EmitInt16(dwarf::DWARF_VERSION);

    Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
    const MCSection *ISec = Asm->getObjFileLowering().getDwarfInfoSection();
    Asm->EmitSectionOffset(Asm->GetTempSymbol(ISec->getLabelBeginName(),
                                              TheCU->getUniqueID()),
                           DwarfInfoSectionSym);

    Asm->OutStreamer.AddComment("Compilation Unit Length");
    Asm->EmitLabelDifference(Asm->GetTempSymbol(ISec->getLabelEndName(),
                                                TheCU->getUniqueID()),
                             Asm->GetTempSymbol(ISec->getLabelBeginName(),
                                                TheCU->getUniqueID()),
                             4);

    const StringMap<DIE*> &Globals = TheCU->getGlobalTypes();
    for (StringMap<DIE*>::const_iterator
           GI = Globals.begin(), GE = Globals.end(); GI != GE; ++GI) {
      const char *Name = GI->getKeyData();
      DIE *Entity = GI->second;

      if (Asm->isVerbose()) Asm->OutStreamer.AddComment("DIE offset");
      Asm->EmitInt32(Entity->getOffset());

      if (Asm->isVerbose()) Asm->OutStreamer.AddComment("External Name");
      // Emit the name with a terminating null byte.
      Asm->OutStreamer.EmitBytes(StringRef(Name, GI->getKeyLength()+1));
    }

    Asm->OutStreamer.AddComment("End Mark");
    Asm->EmitInt32(0);
    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("pubtypes_end",
                                                  TheCU->getUniqueID()));
  }
}

// Emit strings into a string section.
void DwarfUnits::emitStrings(const MCSection *StrSection,
                             const MCSection *OffsetSection = NULL,
                             const MCSymbol *StrSecSym = NULL) {

  if (StringPool.empty()) return;

  // Start the dwarf str section.
  Asm->OutStreamer.SwitchSection(StrSection);

  // Get all of the string pool entries and put them in an array by their ID so
  // we can sort them.
  SmallVector<std::pair<unsigned,
                 StringMapEntry<std::pair<MCSymbol*, unsigned> >*>, 64> Entries;

  for (StringMap<std::pair<MCSymbol*, unsigned> >::iterator
         I = StringPool.begin(), E = StringPool.end();
       I != E; ++I)
    Entries.push_back(std::make_pair(I->second.second, &*I));

  array_pod_sort(Entries.begin(), Entries.end());

  for (unsigned i = 0, e = Entries.size(); i != e; ++i) {
    // Emit a label for reference from debug information entries.
    Asm->OutStreamer.EmitLabel(Entries[i].second->getValue().first);

    // Emit the string itself with a terminating null byte.
    Asm->OutStreamer.EmitBytes(StringRef(Entries[i].second->getKeyData(),
                                         Entries[i].second->getKeyLength()+1));
  }

  // If we've got an offset section go ahead and emit that now as well.
  if (OffsetSection) {
    Asm->OutStreamer.SwitchSection(OffsetSection);
    unsigned offset = 0;
    unsigned size = 4; // FIXME: DWARF64 is 8.
    for (unsigned i = 0, e = Entries.size(); i != e; ++i) {
      Asm->OutStreamer.EmitIntValue(offset, size);
      offset += Entries[i].second->getKeyLength() + 1;
    }
  }
}

// Emit strings into a string section.
void DwarfUnits::emitAddresses(const MCSection *AddrSection) {

  if (AddressPool.empty()) return;

  // Start the dwarf addr section.
  Asm->OutStreamer.SwitchSection(AddrSection);

  // Get all of the string pool entries and put them in an array by their ID so
  // we can sort them.
  SmallVector<std::pair<unsigned,
                        std::pair<MCSymbol*, unsigned>* >, 64> Entries;

  for (DenseMap<MCSymbol*, std::pair<MCSymbol*, unsigned> >::iterator
         I = AddressPool.begin(), E = AddressPool.end();
       I != E; ++I)
    Entries.push_back(std::make_pair(I->second.second, &(I->second)));

  array_pod_sort(Entries.begin(), Entries.end());

  for (unsigned i = 0, e = Entries.size(); i != e; ++i) {
    // Emit a label for reference from debug information entries.
    MCSymbol *Sym = Entries[i].second->first;
    if (Sym)
      Asm->EmitLabelReference(Entries[i].second->first,
                              Asm->getDataLayout().getPointerSize());
    else
      Asm->OutStreamer.EmitIntValue(0, Asm->getDataLayout().getPointerSize());
  }

}

// Emit visible names into a debug str section.
void DwarfDebug::emitDebugStr() {
  DwarfUnits &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
  Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
}

// Emit visible names into a debug loc section.
void DwarfDebug::emitDebugLoc() {
  if (DotDebugLocEntries.empty())
    return;

  for (SmallVector<DotDebugLocEntry, 4>::iterator
         I = DotDebugLocEntries.begin(), E = DotDebugLocEntries.end();
       I != E; ++I) {
    DotDebugLocEntry &Entry = *I;
    if (I + 1 != DotDebugLocEntries.end())
      Entry.Merge(I+1);
  }

  // Start the dwarf loc section.
  Asm->OutStreamer.SwitchSection(
    Asm->getObjFileLowering().getDwarfLocSection());
  unsigned char Size = Asm->getDataLayout().getPointerSize();
  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("debug_loc", 0));
  unsigned index = 1;
  for (SmallVector<DotDebugLocEntry, 4>::iterator
         I = DotDebugLocEntries.begin(), E = DotDebugLocEntries.end();
       I != E; ++I, ++index) {
    DotDebugLocEntry &Entry = *I;
    if (Entry.isMerged()) continue;
    if (Entry.isEmpty()) {
      Asm->OutStreamer.EmitIntValue(0, Size);
      Asm->OutStreamer.EmitIntValue(0, Size);
      Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("debug_loc", index));
    } else {
      Asm->OutStreamer.EmitSymbolValue(Entry.Begin, Size);
      Asm->OutStreamer.EmitSymbolValue(Entry.End, Size);
      DIVariable DV(Entry.Variable);
      Asm->OutStreamer.AddComment("Loc expr size");
      MCSymbol *begin = Asm->OutStreamer.getContext().CreateTempSymbol();
      MCSymbol *end = Asm->OutStreamer.getContext().CreateTempSymbol();
      Asm->EmitLabelDifference(end, begin, 2);
      Asm->OutStreamer.EmitLabel(begin);
      if (Entry.isInt()) {
        DIBasicType BTy(DV.getType());
        if (BTy.Verify() &&
            (BTy.getEncoding()  == dwarf::DW_ATE_signed
             || BTy.getEncoding() == dwarf::DW_ATE_signed_char)) {
          Asm->OutStreamer.AddComment("DW_OP_consts");
          Asm->EmitInt8(dwarf::DW_OP_consts);
          Asm->EmitSLEB128(Entry.getInt());
        } else {
          Asm->OutStreamer.AddComment("DW_OP_constu");
          Asm->EmitInt8(dwarf::DW_OP_constu);
          Asm->EmitULEB128(Entry.getInt());
        }
      } else if (Entry.isLocation()) {
        if (!DV.hasComplexAddress())
          // Regular entry.
          Asm->EmitDwarfRegOp(Entry.Loc);
        else {
          // Complex address entry.
          unsigned N = DV.getNumAddrElements();
          unsigned i = 0;
          if (N >= 2 && DV.getAddrElement(0) == DIBuilder::OpPlus) {
            if (Entry.Loc.getOffset()) {
              i = 2;
              Asm->EmitDwarfRegOp(Entry.Loc);
              Asm->OutStreamer.AddComment("DW_OP_deref");
              Asm->EmitInt8(dwarf::DW_OP_deref);
              Asm->OutStreamer.AddComment("DW_OP_plus_uconst");
              Asm->EmitInt8(dwarf::DW_OP_plus_uconst);
              Asm->EmitSLEB128(DV.getAddrElement(1));
            } else {
              // If first address element is OpPlus then emit
              // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
              MachineLocation Loc(Entry.Loc.getReg(), DV.getAddrElement(1));
              Asm->EmitDwarfRegOp(Loc);
              i = 2;
            }
          } else {
            Asm->EmitDwarfRegOp(Entry.Loc);
          }

          // Emit remaining complex address elements.
          for (; i < N; ++i) {
            uint64_t Element = DV.getAddrElement(i);
            if (Element == DIBuilder::OpPlus) {
              Asm->EmitInt8(dwarf::DW_OP_plus_uconst);
              Asm->EmitULEB128(DV.getAddrElement(++i));
            } else if (Element == DIBuilder::OpDeref) {
              if (!Entry.Loc.isReg())
                Asm->EmitInt8(dwarf::DW_OP_deref);
            } else
              llvm_unreachable("unknown Opcode found in complex address");
          }
        }
      }
      // else ... ignore constant fp. There is not any good way to
      // to represent them here in dwarf.
      Asm->OutStreamer.EmitLabel(end);
    }
  }
}

// Emit visible names into a debug aranges section.
void DwarfDebug::emitDebugARanges() {
  // Start the dwarf aranges section.
  Asm->OutStreamer.SwitchSection(
                          Asm->getObjFileLowering().getDwarfARangesSection());
}

// Emit visible names into a debug ranges section.
void DwarfDebug::emitDebugRanges() {
  // Start the dwarf ranges section.
  Asm->OutStreamer.SwitchSection(
    Asm->getObjFileLowering().getDwarfRangesSection());
  unsigned char Size = Asm->getDataLayout().getPointerSize();
  for (SmallVector<const MCSymbol *, 8>::iterator
         I = DebugRangeSymbols.begin(), E = DebugRangeSymbols.end();
       I != E; ++I) {
    if (*I)
      Asm->OutStreamer.EmitSymbolValue(const_cast<MCSymbol*>(*I), Size);
    else
      Asm->OutStreamer.EmitIntValue(0, Size);
  }
}

// Emit visible names into a debug macinfo section.
void DwarfDebug::emitDebugMacInfo() {
  if (const MCSection *LineInfo =
      Asm->getObjFileLowering().getDwarfMacroInfoSection()) {
    // Start the dwarf macinfo section.
    Asm->OutStreamer.SwitchSection(LineInfo);
  }
}

// Emit inline info using following format.
// Section Header:
// 1. length of section
// 2. Dwarf version number
// 3. address size.
//
// Entries (one "entry" for each function that was inlined):
//
// 1. offset into __debug_str section for MIPS linkage name, if exists;
//   otherwise offset into __debug_str for regular function name.
// 2. offset into __debug_str section for regular function name.
// 3. an unsigned LEB128 number indicating the number of distinct inlining
// instances for the function.
//
// The rest of the entry consists of a {die_offset, low_pc} pair for each
// inlined instance; the die_offset points to the inlined_subroutine die in the
// __debug_info section, and the low_pc is the starting address for the
// inlining instance.
void DwarfDebug::emitDebugInlineInfo() {
  if (!Asm->MAI->doesDwarfUseInlineInfoSection())
    return;

  if (!FirstCU)
    return;

  Asm->OutStreamer.SwitchSection(
                        Asm->getObjFileLowering().getDwarfDebugInlineSection());

  Asm->OutStreamer.AddComment("Length of Debug Inlined Information Entry");
  Asm->EmitLabelDifference(Asm->GetTempSymbol("debug_inlined_end", 1),
                           Asm->GetTempSymbol("debug_inlined_begin", 1), 4);

  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("debug_inlined_begin", 1));

  Asm->OutStreamer.AddComment("Dwarf Version");
  Asm->EmitInt16(dwarf::DWARF_VERSION);
  Asm->OutStreamer.AddComment("Address Size (in bytes)");
  Asm->EmitInt8(Asm->getDataLayout().getPointerSize());

  for (SmallVector<const MDNode *, 4>::iterator I = InlinedSPNodes.begin(),
         E = InlinedSPNodes.end(); I != E; ++I) {

    const MDNode *Node = *I;
    DenseMap<const MDNode *, SmallVector<InlineInfoLabels, 4> >::iterator II
      = InlineInfo.find(Node);
    SmallVector<InlineInfoLabels, 4> &Labels = II->second;
    DISubprogram SP(Node);
    StringRef LName = SP.getLinkageName();
    StringRef Name = SP.getName();

    Asm->OutStreamer.AddComment("MIPS linkage name");
    if (LName.empty())
      Asm->EmitSectionOffset(InfoHolder.getStringPoolEntry(Name),
                             DwarfStrSectionSym);
    else
      Asm->EmitSectionOffset(InfoHolder
                             .getStringPoolEntry(getRealLinkageName(LName)),
                             DwarfStrSectionSym);

    Asm->OutStreamer.AddComment("Function name");
    Asm->EmitSectionOffset(InfoHolder.getStringPoolEntry(Name),
                           DwarfStrSectionSym);
    Asm->EmitULEB128(Labels.size(), "Inline count");

    for (SmallVector<InlineInfoLabels, 4>::iterator LI = Labels.begin(),
           LE = Labels.end(); LI != LE; ++LI) {
      if (Asm->isVerbose()) Asm->OutStreamer.AddComment("DIE offset");
      Asm->EmitInt32(LI->second->getOffset());

      if (Asm->isVerbose()) Asm->OutStreamer.AddComment("low_pc");
      Asm->OutStreamer.EmitSymbolValue(LI->first,
                                       Asm->getDataLayout().getPointerSize());
    }
  }

  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("debug_inlined_end", 1));
}

// DWARF5 Experimental Separate Dwarf emitters.

// This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list,
// DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id,
// DW_AT_ranges_base, DW_AT_addr_base. If DW_AT_ranges is present,
// DW_AT_low_pc and DW_AT_high_pc are not used, and vice versa.
CompileUnit *DwarfDebug::constructSkeletonCU(const MDNode *N) {
  DICompileUnit DIUnit(N);
  CompilationDir = DIUnit.getDirectory();

  DIE *Die = new DIE(dwarf::DW_TAG_compile_unit);
  CompileUnit *NewCU = new CompileUnit(GlobalCUIndexCount++,
                                       DIUnit.getLanguage(), Die, Asm,
                                       this, &SkeletonHolder);

  SmallString<16> T(DIUnit.getFilename());
  sys::path::replace_extension(T, ".dwo");
  StringRef FN = sys::path::filename(T);
  NewCU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name, FN);

  // This should be a unique identifier when we want to build .dwp files.
  NewCU->addUInt(Die, dwarf::DW_AT_GNU_dwo_id, dwarf::DW_FORM_data8, 0);

  // FIXME: The addr base should be relative for each compile unit, however,
  // this one is going to be 0 anyhow.
  NewCU->addUInt(Die, dwarf::DW_AT_GNU_addr_base, dwarf::DW_FORM_sec_offset, 0);

  // 2.17.1 requires that we use DW_AT_low_pc for a single entry point
  // into an entity. We're using 0, or a NULL label for this.
  NewCU->addUInt(Die, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);

  // DW_AT_stmt_list is a offset of line number information for this
  // compile unit in debug_line section.
  if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
    NewCU->addLabel(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_sec_offset,
                    DwarfLineSectionSym);
  else
    NewCU->addUInt(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_sec_offset, 0);

  if (!CompilationDir.empty())
    NewCU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);

  SkeletonHolder.addUnit(NewCU);
  SkeletonCUs.push_back(NewCU);

  return NewCU;
}

void DwarfDebug::emitSkeletonAbbrevs(const MCSection *Section) {
  assert(useSplitDwarf() && "No split dwarf debug info?");
  emitAbbrevs(Section, &SkeletonAbbrevs);
}

// Emit the .debug_info.dwo section for separated dwarf. This contains the
// compile units that would normally be in debug_info.
void DwarfDebug::emitDebugInfoDWO() {
  assert(useSplitDwarf() && "No split dwarf debug info?");
  InfoHolder.emitUnits(this, Asm->getObjFileLowering().getDwarfInfoDWOSection(),
                       Asm->getObjFileLowering().getDwarfAbbrevDWOSection(),
                       DwarfAbbrevDWOSectionSym);
}

// Emit the .debug_abbrev.dwo section for separated dwarf. This contains the
// abbreviations for the .debug_info.dwo section.
void DwarfDebug::emitDebugAbbrevDWO() {
  assert(useSplitDwarf() && "No split dwarf?");
  emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection(),
              &Abbreviations);
}

// Emit the .debug_str.dwo section for separated dwarf. This contains the
// string section and is identical in format to traditional .debug_str
// sections.
void DwarfDebug::emitDebugStrDWO() {
  assert(useSplitDwarf() && "No split dwarf?");
  const MCSection *OffSec = Asm->getObjFileLowering()
                            .getDwarfStrOffDWOSection();
  const MCSymbol *StrSym = DwarfStrSectionSym;
  InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(),
                         OffSec, StrSym);
}