[BOLT][DWARF] Fix TU Index handling for DWARF4/5

[ayermolo]

Summary

When we generate split dwarf with -fdebug-types-section we will have
.debug_types.dwo sections. These go into TU Index when we run llvm-dwp. BOLT was
not handling DWP input correctly with this section.

Added support for handling DWP with TU Index as an input and output for DWARF4.
Added support for handling DWP with TU Index as an input for DWARF5

[ayermolo]

missed llvm-dwp

[maksfb]

Added support for handling it when DWP output or DWP is output for DWARF4. For DWARF5 it just handles it as an input for now.

Could you please rephrase?

bolt/include/bolt/Rewrite/DWARFRewriter.h

31

Or DebugTypesSignaturesPerCUMap.

bolt/lib/Rewrite/DWARFRewriter.cpp

738

If you are validating the input here, then it's better to issue an error as llvm_unreachable() has no effect in no-assert builds.

1261

1263

Could you add detailed comments? E.g., it's unclear which parameters are input and which are output.

1291

Is reinterpret_cast<> necessary here? Does StringRef(DWOTUSection) not work? Do you actually need to return StringRef from the function, as it's always a reference to DWOTUSection which is a parameter to the function?

1405

Should this be an error instead?

1511

1622

Likewise, should this be an error?

[ayermolo]

bolt/include/bolt/Rewrite/DWARFRewriter.h

31

oh yeah, that's better. thx

bolt/lib/Rewrite/DWARFRewriter.cpp

738

Ah right forgot about that. K, will change to llvm::errs() << "BOLT-ERROR: " ?

1291

This avoids a bug where a null byte is interpreted as the end of string.
I thought returning StringRef would be cleaner then putting this logic on the callee side.

1405

llvm::errs() << "BOLT-ERROR: "
exit(1);
?

1622

Because we are validating input? Way I thought about it, is that it's not a common path, and more of a sanity check so assert would be more appropriate.

[maksfb]

bolt/lib/Rewrite/DWARFRewriter.cpp

738

What's the desired action? Do you want to terminate the processing? Alternatively, you can return an error and handle it from a caller.

1291

Sorry, I don't follow. Where is null-byte bug manifesting itself? Both, std::string and StringRef allow null characters, right?

1622

If you are validating an internal assumption, then it's fine to leave the assert() as is.

[ayermolo]

bolt/lib/Rewrite/DWARFRewriter.cpp

738

yes, I think we should terminate process.

1291

I ran into this issue in updateDebugData. Don't quite remember all the details, but when doing conversion from std::string to StringRef using StringRef(std::string) semantics if there were null bytes in std::string it will think that's the end of the string, so StringRef will get the length wrong. Thus StringRef will only capture part of the string.

1622

Yep, exactly.

[ayermolo]

Addressing comments.

[ayermolo]

formating

[ayermolo]

refactored extractDWOTUFromDWP

[maksfb]

bolt/lib/Rewrite/DWARFRewriter.cpp

738

1266

Should this be const?

1316

1334–1336

1405

[ayermolo]

bolt/lib/Rewrite/DWARFRewriter.cpp

1316

If this is const compiler errors out on
for (uint64_t Val : TypeSignaturesPerCU[DWOId])

[ayermolo]

addressing comments

[ayermolo]

changed type unordered map to const.

[ayermolo]

rebase

[ayermolo]

rebase

[ayermolo]

update with arc diff git merge-base HEAD origin --update D126087

[ayermolo]

rebase ontop of Fix LIT tests on Windows VS2019

[maksfb]

LGTM. Thanks!

bolt/include/bolt/Rewrite/DWARFRewriter.h

 
 #include "bolt/Core/DebugData.h"
 #include "llvm/MC/MCAsmLayout.h"
 #include <cstdint>
 #include <memory>
 #include <mutex>
 #include <set>
 #include <unordered_map>
+#include <unordered_set>
 #include <vector>
 
 namespace llvm {
 
 namespace bolt {
 
 class BinaryContext;
 
 class DWARFRewriter {
+public:
   DWARFRewriter() = delete;
+  using DebugTypesSignaturesPerCUMap =
+      std::unordered_map<uint64_t, std::unordered_set<uint64_t>>;
 
+private:
   BinaryContext &BC;
 
   std::mutex DebugInfoPatcherMutex;
 
   /// Stores and serializes information that will be put into the
   /// .debug_ranges DWARF section.
   std::unique_ptr<DebugRangesSectionWriter> RangesSectionWriter;
 
private:
   /// Abbrev section writers for DWOs.
   DebugAbbrevDWOWriters BinaryDWOAbbrevWriters;
 
   using DebugInfoDWOPatchers =
       std::unordered_map<uint64_t, std::unique_ptr<SimpleBinaryPatcher>>;
   /// Binary patchers for DWO debug_info sections.
   DebugInfoDWOPatchers BinaryDWODebugInfoPatchers;
 
+  /// Stores all the Type Signatures for DWO CU.
+  DebugTypesSignaturesPerCUMap TypeSignaturesPerCU;
+
   std::mutex LocListDebugInfoPatchesMutex;
 
   /// DWARFLegacy is all DWARF versions before DWARF 5.
   enum class DWARFVersion { DWARFLegacy, DWARF5 };
 
   /// Update debug info for all DIEs in \p Unit.
   void updateUnitDebugInfo(DWARFUnit &Unit,
                            DebugInfoBinaryPatcher &DebugInfoPatcher,

bolt/lib/Rewrite/DWARFRewriter.cpp

 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/ThreadPool.h"
 #include "llvm/Support/ToolOutputFile.h"
 #include <algorithm>
 #include <cstdint>
 #include <string>
 #include <unordered_map>
+#include <utility>
+#include <vector>
 
 #undef  DEBUG_TYPE
 #define DEBUG_TYPE "bolt"
 
 LLVM_ATTRIBUTE_UNUSED
 static void printDie(const DWARFDie &DIE) {
   DIDumpOptions DumpOpts;
   DumpOpts.ShowForm = true;
void DWARFRewriter::updateUnitDebugInfo(
   std::map<DebugAddressRangesVector, uint64_t> CachedRanges;
 
   uint64_t DIEOffset = Unit.getOffset() + Unit.getHeaderSize();
   uint64_t NextCUOffset = Unit.getNextUnitOffset();
   DWARFDebugInfoEntry Die;
   DWARFDataExtractor DebugInfoData = Unit.getDebugInfoExtractor();
   uint32_t Depth = 0;
 
+  bool IsDWP = false;
+  if (DWARFContext *DWOCtx = BC.getDWOContext())
+    IsDWP = !DWOCtx->getCUIndex().getRows().empty();
+
   while (
       DIEOffset < NextCUOffset &&
       Die.extractFast(Unit, &DIEOffset, DebugInfoData, NextCUOffset, Depth)) {
     if (const DWARFAbbreviationDeclaration *AbbrDecl =
             Die.getAbbreviationDeclarationPtr()) {
       if (AbbrDecl->hasChildren())
         ++Depth;
     } else {
default: {
             DebugInfoPatcher.addUDataPatch(AttrOffset, Index, AttrVal->Size);
           } else {
             DebugInfoPatcher.addLE64Patch(AttrOffset, NewAddress);
           }
         } else if (opts::Verbosity >= 1) {
           errs() << "BOLT-WARNING: unexpected form value for attribute at 0x"
                  << Twine::utohexstr(AttrOffset);
         }
+      } else if (IsDWP && Unit.isDWOUnit()) {
+        // Not a common path so don't want to search all DIEs all the time.
+        Optional<AttrInfo> SignatureAttrVal =
+            findAttributeInfo(DIE, dwarf::DW_AT_signature);
+        if (!SignatureAttrVal)
+          continue;
+        // If input is DWP file we need to keep track of which TU came from each
+        // CU, so we can write it out correctly.
+        if (Optional<uint64_t> Val = SignatureAttrVal->V.getAsReferenceUVal())
+          TypeSignaturesPerCU[*DIE.getDwarfUnit()->getDWOId()].insert(*Val);
+        else {
+          llvm::errs() << "BOT-ERROR: DW_AT_signature form is not supported.\n";
+          exit(1);
+        }
       }
     }
     }
 
     // Handling references.
     assert(DIE.isValid() && "Invalid DIE.");
     const DWARFAbbreviationDeclaration *AbbrevDecl =
         DIE.getAbbreviationDeclarationPtr();

 
 // Exctracts an appropriate slice if input is DWP.
 // Applies patches or overwrites the section.
 Optional<StringRef>
 updateDebugData(DWARFContext &DWCtx, std::string &Storage,
                 StringRef SectionName, StringRef SectionContents,
                 const StringMap<KnownSectionsEntry> &KnownSections,
                 MCStreamer &Streamer, DWARFRewriter &Writer,
-                const DWARFUnitIndex::Entry *DWOEntry, uint64_t DWOId,
+                const DWARFUnitIndex::Entry *CUDWOEntry, uint64_t DWOId,
                 std::unique_ptr<DebugBufferVector> &OutputBuffer,
                 DebugRangeListsSectionWriter *RangeListsWriter) {
   auto applyPatch = [&](DebugInfoBinaryPatcher *Patcher,
                         StringRef Data) -> StringRef {
     Patcher->computeNewOffsets(DWCtx, true);
     Storage = Patcher->patchBinary(Data);
     return StringRef(Storage.c_str(), Storage.size());
   };
if (DWOEntry) {
       OutData = OutData.substr(DWPOffset, DWOContrubution->Length);
     }
     return OutData;
   };
 
   auto SectionIter = KnownSections.find(SectionName);
   if (SectionIter == KnownSections.end())
     return None;
+
   Streamer.SwitchSection(SectionIter->second.first);
   StringRef OutData = SectionContents;
   uint32_t DWPOffset = 0;
 
   switch (SectionIter->second.second) {
   default: {
     if (!SectionName.equals("debug_str.dwo"))
       errs() << "BOLT-WARNING: unsupported debug section: " << SectionName
              << "\n";
     return OutData;
   }
   case DWARFSectionKind::DW_SECT_INFO: {
-    OutData = getSliceData(DWOEntry, OutData, DWARFSectionKind::DW_SECT_INFO,
+    OutData = getSliceData(CUDWOEntry, OutData, DWARFSectionKind::DW_SECT_INFO,
                            DWPOffset);
     DebugInfoBinaryPatcher *Patcher = llvm::cast<DebugInfoBinaryPatcher>(
         Writer.getBinaryDWODebugInfoPatcher(DWOId));
     return applyPatch(Patcher, OutData);
   }
   case DWARFSectionKind::DW_SECT_EXT_TYPES: {
-    return getSliceData(DWOEntry, OutData, DWARFSectionKind::DW_SECT_EXT_TYPES,
+    return getSliceData(nullptr, OutData, DWARFSectionKind::DW_SECT_EXT_TYPES,
                         DWPOffset);
   }
   case DWARFSectionKind::DW_SECT_STR_OFFSETS: {
-    return getSliceData(DWOEntry, OutData,
+    return getSliceData(CUDWOEntry, OutData,
                         DWARFSectionKind::DW_SECT_STR_OFFSETS, DWPOffset);
   }
   case DWARFSectionKind::DW_SECT_ABBREV: {
     DebugAbbrevWriter *AbbrevWriter = Writer.getBinaryDWOAbbrevWriter(DWOId);
     OutputBuffer = AbbrevWriter->finalize();
     // Creating explicit StringRef here, otherwise
     // with impicit conversion it will take null byte as end of
     // string.
     return StringRef(reinterpret_cast<const char *>(OutputBuffer->data()),
                      OutputBuffer->size());
   }
   case DWARFSectionKind::DW_SECT_EXT_LOC:
   case DWARFSectionKind::DW_SECT_LOCLISTS: {
     DebugLocWriter *LocWriter = Writer.getDebugLocWriter(DWOId);
     OutputBuffer = LocWriter->getBuffer();
     // Creating explicit StringRef here, otherwise
     // with impicit conversion it will take null byte as end of
     // string.
     return StringRef(reinterpret_cast<const char *>(OutputBuffer->data()),
                      OutputBuffer->size());
   }
   case DWARFSectionKind::DW_SECT_LINE: {
-    return getSliceData(DWOEntry, OutData, DWARFSectionKind::DW_SECT_LINE,
+    return getSliceData(CUDWOEntry, OutData, DWARFSectionKind::DW_SECT_LINE,
                         DWPOffset);
   }
   case DWARFSectionKind::DW_SECT_RNGLISTS: {
     OutputBuffer = RangeListsWriter->releaseBuffer();
     return StringRef(reinterpret_cast<const char *>(OutputBuffer->data()),
                      OutputBuffer->size());
   }
   }
 }
 
 } // namespace
 
+struct TUContribution {
+  uint64_t Signature{0};
+  uint32_t Length{0};
+};
+using TUContributionVector = std::vector<TUContribution>;
+/// Iterates over all the signatures used in this CU, and
+/// uses TU Index to extract their contributions from the DWP file.
+/// It stores them in DWOTUSection.
+static std::string extractDWOTUFromDWP(
+    DWARFRewriter::DebugTypesSignaturesPerCUMap &TypeSignaturesPerCU,
+    const DWARFUnitIndex &TUIndex, StringRef Contents,
+    TUContributionVector &TUContributionsToCU, uint64_t DWOId) {
+  std::string DWOTUSection;
+  using TUEntry =
+      std::pair<uint64_t, const DWARFUnitIndex::Entry::SectionContribution *>;
+  std::vector<TUEntry> TUContributions;
+  for (uint64_t TUSignature : TypeSignaturesPerCU[DWOId]) {
+    const DWARFUnitIndex::Entry *TUDWOEntry = TUIndex.getFromHash(TUSignature);
+    const DWARFUnitIndex::Entry::SectionContribution *C =
+        TUDWOEntry->getContribution(DW_SECT_EXT_TYPES);
+    TUContributions.emplace_back(TUSignature, C);
+  }
+
+  // Sorting so it's easy to compare output.
+  // They should be sharing the same Abbrev.
+  std::sort(TUContributions.begin(), TUContributions.end(),
+            [](const TUEntry &V1, const TUEntry &V2) -> bool {
+              return V1.second->Offset < V2.second->Offset;
+            });
+
+  for (auto &PairEntry : TUContributions) {
+    const DWARFUnitIndex::Entry::SectionContribution *C = PairEntry.second;
+    const uint64_t TUSignature = PairEntry.first;
+    DWOTUSection.append(Contents.slice(C->Offset, C->Offset + C->Length).str());
+    TUContributionsToCU.push_back({TUSignature, C->Length});
+  }
+  return DWOTUSection;
+}
+
+static void extractDWOTUFromDWO(StringRef Contents,
+                                TUContributionVector &TUContributionsToCU) {
+  uint64_t Offset = 0;
+  DataExtractor Data(Contents, true, 0);
+  while (Data.isValidOffset(Offset)) {
+    auto PrevOffset = Offset;
+    // Length of the unit, including the 4 byte length field.
+    const uint32_t Length = Data.getU32(&Offset) + 4;
+
+    Data.getU16(&Offset); // Version
+    Data.getU32(&Offset); // Abbrev offset
+    Data.getU8(&Offset);  // Address size
+    const auto TUSignature = Data.getU64(&Offset);
+    Offset = PrevOffset + Length;
+    TUContributionsToCU.push_back({TUSignature, Length});
+  }
+}
+
+static void extractTypesFromDWPDWARF5(
+    const MCObjectFileInfo &MCOFI, const DWARFUnitIndex &TUIndex,
+    DWARFRewriter::DebugTypesSignaturesPerCUMap &TypeSignaturesPerCU,
+    MCStreamer &Streamer, StringRef Contents, uint64_t DWOId) {
+  std::vector<const DWARFUnitIndex::Entry::SectionContribution *>
+      TUContributions;
+  for (uint64_t Val : TypeSignaturesPerCU[DWOId]) {
+    const DWARFUnitIndex::Entry *TUE = TUIndex.getFromHash(Val);
+    const DWARFUnitIndex::Entry::SectionContribution *C =
+        TUE->getContribution(DWARFSectionKind::DW_SECT_INFO);
+    TUContributions.push_back(C);
+  }
+  // Sorting so it's easy to compare output.
+  // They should be sharing the same Abbrev.
+  std::sort(TUContributions.begin(), TUContributions.end(),
+            [](const DWARFUnitIndex::Entry::SectionContribution *V1,
+               const DWARFUnitIndex::Entry::SectionContribution *V2) -> bool {
+              return V1->Offset < V2->Offset;
+            });
+  Streamer.SwitchSection(MCOFI.getDwarfInfoDWOSection());
+  for (const auto *C : TUContributions) {
+    Streamer.emitBytes(Contents.slice(C->Offset, C->Offset + C->Length));
+  }
+}
+
 void DWARFRewriter::writeDWP(
     std::unordered_map<uint64_t, std::string> &DWOIdToName) {
   SmallString<0> OutputNameStr;
   StringRef OutputName;
   if (opts::DwarfOutputPath.empty()) {
     OutputName =
         Twine(opts::OutputFilename).concat(".dwp").toStringRef(OutputNameStr);
   } else {
void DWARFRewriter::writeDWP(
 
   // Data Structures for DWP book keeping
   // Size of array corresponds to the number of sections supported by DWO format
   // in DWARF4/5.
   uint32_t ContributionOffsets[8] = {};
   std::deque<SmallString<32>> UncompressedSections;
   DWPStringPool Strings(*Streamer, StrSection);
   MapVector<uint64_t, UnitIndexEntry> IndexEntries;
-  constexpr uint32_t IndexVersion = 2;
+  MapVector<uint64_t, UnitIndexEntry> TypeIndexEntries;
+  uint16_t Version = 0;
+  uint32_t IndexVersion = 2;
 
   // Setup DWP code once.
   DWARFContext *DWOCtx = BC.getDWOContext();
   const DWARFUnitIndex *CUIndex = nullptr;
+  const DWARFUnitIndex *TUIndex = nullptr;
   bool IsDWP = false;
   if (DWOCtx) {
     CUIndex = &DWOCtx->getCUIndex();
+    TUIndex = &DWOCtx->getTUIndex();
     IsDWP = !CUIndex->getRows().empty();
   }
 
   for (const std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units()) {
     Optional<uint64_t> DWOId = CU->getDWOId();
     if (!DWOId)
       continue;
 
     // Skipping CUs that we failed to load.
     Optional<DWARFUnit *> DWOCU = BC.getDWOCU(*DWOId);
     if (!DWOCU)
       continue;
 
-    assert(CU->getVersion() <= 4 && "For DWP output only DWARF4 is supported");
+    if (Version == 0) {
+      Version = CU->getVersion();
+      IndexVersion = Version < 5 ? 2 : 5;
+    } else if (Version != CU->getVersion()) {
+      llvm::errs() << "BOLT-ERROR: Incompatible DWARF compile unit versions.\n";
+      exit(1);
+    }
+
     UnitIndexEntry CurEntry = {};
     CurEntry.DWOName =
         dwarf::toString(CU->getUnitDIE().find(
                             {dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}),
                         "");
     const char *Name = CU->getUnitDIE().getShortName();
     if (Name)
       CurEntry.Name = Name;
     StringRef CurStrSection;
     StringRef CurStrOffsetSection;
 
     // This maps each section contained in this file to its length.
     // This information is later on used to calculate the contributions,
     // i.e. offset and length, of each compile/type unit to a section.
     std::vector<std::pair<DWARFSectionKind, uint32_t>> SectionLength;
 
-    const DWARFUnitIndex::Entry *DWOEntry = nullptr;
+    const DWARFUnitIndex::Entry *CUDWOEntry = nullptr;
     if (IsDWP)
-      DWOEntry = CUIndex->getFromHash(*DWOId);
+      CUDWOEntry = CUIndex->getFromHash(*DWOId);
 
     bool StrSectionWrittenOut = false;
     const object::ObjectFile *DWOFile =
         (*DWOCU)->getContext().getDWARFObj().getFile();
 
     DebugRangeListsSectionWriter *RangeListssWriter = nullptr;
     if (CU->getVersion() == 5) {
       assert(RangeListsWritersByCU.count(*DWOId) != 0 &&
              "No RangeListsWriter for DWO ID.");
       RangeListssWriter = RangeListsWritersByCU[*DWOId].get();
     }
+    std::string DWOTUSection;
+    TUContributionVector TUContributionsToCU;
     for (const SectionRef &Section : DWOFile->sections()) {
+      std::string DWOTUSection;
       std::string Storage = "";
       std::unique_ptr<DebugBufferVector> OutputData;
       StringRef SectionName = getSectionName(Section);
-      Expected<StringRef> Contents = Section.getContents();
-      assert(Contents && "Invalid contents.");
-      Optional<StringRef> TOutData =
-          updateDebugData((*DWOCU)->getContext(), Storage, SectionName,
-                          *Contents, KnownSections, *Streamer, *this, DWOEntry,
-                          *DWOId, OutputData, RangeListssWriter);
+      Expected<StringRef> ContentsExp = Section.getContents();
+      assert(ContentsExp && "Invalid contents.");
+      StringRef Contents = *ContentsExp;
+      const bool IsTypesDWO = SectionName == "debug_types.dwo";
+      if (IsDWP && IsTypesDWO) {
+        assert(TUIndex &&
+               "DWP Input with .debug_types.dwo section with TU Index.");
+        DWOTUSection =
+            extractDWOTUFromDWP(TypeSignaturesPerCU, *TUIndex, Contents,
+                                TUContributionsToCU, *DWOId);
+        Contents = DWOTUSection;
+      } else if (IsTypesDWO) {
+        extractDWOTUFromDWO(Contents, TUContributionsToCU);
+      }
+
+      Optional<StringRef> TOutData = updateDebugData(
+          (*DWOCU)->getContext(), Storage, SectionName, Contents, KnownSections,
+          *Streamer, *this, CUDWOEntry, *DWOId, OutputData, RangeListssWriter);
       if (!TOutData)
         continue;
 
       StringRef OutData = *TOutData;
-      StringRef Name = getSectionName(Section);
-      if (Name.equals("debug_str.dwo")) {
+      if (IsTypesDWO) {
+        Streamer->emitBytes(OutData);
+        continue;
+      }
+
+      if (SectionName.equals("debug_str.dwo")) {
         CurStrSection = OutData;
       } else {
         // Since handleDebugDataPatching returned true, we already know this is
         // a known section.
-        auto SectionIter = KnownSections.find(Name);
+        auto SectionIter = KnownSections.find(SectionName);
         if (SectionIter->second.second == DWARFSectionKind::DW_SECT_STR_OFFSETS)
           CurStrOffsetSection = OutData;
         else
           Streamer->emitBytes(OutData);
         auto Index =
             getContributionIndex(SectionIter->second.second, IndexVersion);
         CurEntry.Contributions[Index].Offset = ContributionOffsets[Index];
         CurEntry.Contributions[Index].Length = OutData.size();
for (const std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units()) {
     CompileUnitIdentifiers CUI{*DWOId, CurEntry.Name.c_str(),
                                CurEntry.DWOName.c_str()};
     auto P = IndexEntries.insert(std::make_pair(CUI.Signature, CurEntry));
     if (!P.second) {
       Error Err = buildDuplicateError(*P.first, CUI, "");
       errs() << "BOLT-ERROR: " << toString(std::move(Err)) << "\n";
       return;
     }
+
+    // Handling TU
+    if (!TUContributionsToCU.empty()) {
+      const unsigned Index =
+          getContributionIndex(DW_SECT_EXT_TYPES, IndexVersion);
+      for (const TUContribution &TUC : TUContributionsToCU) {
+        UnitIndexEntry TUEntry = CurEntry;
+        TUEntry.Contributions[0] = {};
+        TUEntry.Contributions[Index].Offset = ContributionOffsets[Index];
+        TUEntry.Contributions[Index].Length = TUC.Length;
+        ContributionOffsets[Index] += TUEntry.Contributions[Index].Length;
+        TypeIndexEntries.insert(std::make_pair(TUC.Signature, TUEntry));
+      }
+    }
   }
 
+  if (Version < 5) {
+    // Lie about there being no info contributions so the TU index only includes
+    // the type unit contribution for DWARF < 5. In DWARFv5 the TU index has a
+    // contribution to the info section, so we do not want to lie about it.
+    ContributionOffsets[0] = 0;
+  }
+  writeIndex(*Streamer.get(), MCOFI.getDwarfTUIndexSection(),
+             ContributionOffsets, TypeIndexEntries, IndexVersion);
+
+  if (Version < 5) {
     // Lie about the type contribution for DWARF < 5. In DWARFv5 the type
     // section does not exist, so no need to do anything about this.
     ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)] = 0;
+    // Unlie about the info contribution
+    ContributionOffsets[0] = 1;
+  }
   writeIndex(*Streamer.get(), MCOFI.getDwarfCUIndexSection(),
              ContributionOffsets, IndexEntries, IndexVersion);
 
   Streamer->Finish();
   Out->keep();
 }
 
 void DWARFRewriter::writeDWOFiles(
     std::unordered_map<uint64_t, std::string> &DWOIdToName) {
   // Setup DWP code once.
   DWARFContext *DWOCtx = BC.getDWOContext();
   const DWARFUnitIndex *CUIndex = nullptr;
+  const DWARFUnitIndex *TUIndex = nullptr;
   bool IsDWP = false;
   if (DWOCtx) {
     CUIndex = &DWOCtx->getCUIndex();
+    TUIndex = &DWOCtx->getTUIndex();
     IsDWP = !CUIndex->getRows().empty();
   }
 
   for (const std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units()) {
     Optional<uint64_t> DWOId = CU->getDWOId();
     if (!DWOId)
       continue;
 
     // Skipping CUs that we failed to load.
     Optional<DWARFUnit *> DWOCU = BC.getDWOCU(*DWOId);
     if (!DWOCU)
       continue;
 
     std::string CompDir = opts::DwarfOutputPath.empty()
                               ? CU->getCompilationDir()
                               : opts::DwarfOutputPath.c_str();
     std::string ObjectName = getDWOName(*CU.get(), nullptr, DWOIdToName);
     auto FullPath = CompDir.append("/").append(ObjectName);
 
     std::error_code EC;
     std::unique_ptr<ToolOutputFile> TempOut =
         std::make_unique<ToolOutputFile>(FullPath, EC, sys::fs::OF_None);
 
-    const DWARFUnitIndex::Entry *DWOEntry = nullptr;
+    const DWARFUnitIndex::Entry *CUDWOEntry = nullptr;
     if (IsDWP)
-      DWOEntry = CUIndex->getFromHash(*DWOId);
+      CUDWOEntry = CUIndex->getFromHash(*DWOId);
 
     const object::ObjectFile *File =
         (*DWOCU)->getContext().getDWARFObj().getFile();
     std::unique_ptr<BinaryContext> TmpBC = createDwarfOnlyBC(*File);
     std::unique_ptr<MCStreamer> Streamer = TmpBC->createStreamer(TempOut->os());
-    StringMap<KnownSectionsEntry> KnownSections =
-        createKnownSectionsMap(*Streamer->getContext().getObjectFileInfo());
+    const MCObjectFileInfo &MCOFI = *Streamer->getContext().getObjectFileInfo();
+    StringMap<KnownSectionsEntry> KnownSections = createKnownSectionsMap(MCOFI);
 
     DebugRangeListsSectionWriter *RangeListssWriter = nullptr;
     if (CU->getVersion() == 5) {
       assert(RangeListsWritersByCU.count(*DWOId) != 0 &&
              "No RangeListsWriter for DWO ID.");
       RangeListssWriter = RangeListsWritersByCU[*DWOId].get();
 
       // Handling .debug_rnglists.dwo seperatly. The original .o/.dwo might not
       // have .debug_rnglists so won't be part of the loop below.
       if (!RangeListssWriter->empty()) {
         std::string Storage = "";
         std::unique_ptr<DebugBufferVector> OutputData;
         if (Optional<StringRef> OutData = updateDebugData(
                 (*DWOCU)->getContext(), Storage, "debug_rnglists.dwo", "",
-                KnownSections, *Streamer, *this, DWOEntry, *DWOId, OutputData,
+                KnownSections, *Streamer, *this, CUDWOEntry, *DWOId, OutputData,
                 RangeListssWriter))
           Streamer->emitBytes(*OutData);
       }
     }
+
+    TUContributionVector TUContributionsToCU;
     for (const SectionRef &Section : File->sections()) {
       std::string Storage = "";
+      std::string DWOTUSection;
       std::unique_ptr<DebugBufferVector> OutputData;
       StringRef SectionName = getSectionName(Section);
       if (SectionName == "debug_rnglists.dwo")
         continue;
-      Expected<StringRef> Contents = Section.getContents();
-      assert(Contents && "Invalid contents.");
-      if (Optional<StringRef> OutData =
-              updateDebugData((*DWOCU)->getContext(), Storage, SectionName,
-                              *Contents, KnownSections, *Streamer, *this,
-                              DWOEntry, *DWOId, OutputData, RangeListssWriter))
+      Expected<StringRef> ContentsExp = Section.getContents();
+      assert(ContentsExp && "Invalid contents.");
+      StringRef Contents = *ContentsExp;
+      if (IsDWP && SectionName == "debug_types.dwo") {
+        assert(TUIndex &&
+               "DWP Input with .debug_types.dwo section with TU Index.");
+        DWOTUSection =
+            extractDWOTUFromDWP(TypeSignaturesPerCU, *TUIndex, Contents,
+                                TUContributionsToCU, *DWOId);
+        Contents = DWOTUSection;
+      } else if (IsDWP && CU->getVersion() >= 5 &&
+                 SectionName == "debug_info.dwo") {
+        assert(TUIndex &&
+               "DWP Input with .debug_types.dwo section with TU Index.");
+        extractTypesFromDWPDWARF5(MCOFI, *TUIndex, TypeSignaturesPerCU,
+                                  *Streamer, Contents, *DWOId);
+      }
+
+      if (Optional<StringRef> OutData = updateDebugData(
+              (*DWOCU)->getContext(), Storage, SectionName, Contents,
+              KnownSections, *Streamer, *this, CUDWOEntry, *DWOId, OutputData,
+              RangeListssWriter))
         Streamer->emitBytes(*OutData);
     }
     Streamer->Finish();
     TempOut->keep();
   }
 }
 
 void DWARFRewriter::updateGdbIndexSection(CUOffsetMap &CUMap) {

bolt/test/CMakeLists.txt

list(APPEND BOLT_TEST_DEPS
   FileCheck
   llc
   lld
   llvm-config
   llvm-bolt
   llvm-boltdiff
   llvm-bolt-heatmap
   llvm-dwarfdump
+  llvm-dwp
   llvm-mc
   llvm-nm
   llvm-objdump
   llvm-readelf
   llvm-readobj
   llvm-strip
   llvm-objcopy
   merge-fdata

bolt/test/X86/Inputs/dwarf4-ftypes-split-dwarf.s

+# clang++ main.cpp -g2 -gsplit-dwarf=split -gdwarf-4 -fdebug-types-section
+# struct Foo {
+#   char *c1;
+#   char *c2;
+#   char *c3;
+# };
+#
+# struct Foo2 {
+#   char *c1;
+#   char *c2;
+# };
+#
+# int main(int argc, char *argv[]) {
+#   Foo f;
+#   f.c1 = argv[argc];
+#   f.c2 = argv[argc + 1];
+#   f.c3 = argv[argc + 2];
+#   Foo2 f2;
+#   f.c1 = argv[argc + 3];
+#   f.c2 = argv[argc + 4];
+#   return 0;
+# }
+
+  .text
+  .file "main.cpp"
+  .globl  main                            # -- Begin function main
+  .p2align  4, 0x90
+  .type main,@function
+main:                                   # @main
+.Lfunc_begin0:
+  .file 1 "." "main.cpp"
+  .loc  1 12 0                          # main.cpp:12:0
+  .cfi_startproc
+# %bb.0:                                # %entry
+  pushq %rbp
+  .cfi_def_cfa_offset 16
+  .cfi_offset %rbp, -16
+  movq  %rsp, %rbp
+  .cfi_def_cfa_register %rbp
+  movl  $0, -4(%rbp)
+  movl  %edi, -8(%rbp)
+  movq  %rsi, -16(%rbp)
+.Ltmp0:
+  .loc  1 14 10 prologue_end            # main.cpp:14:10
+  movq  -16(%rbp), %rax
+  movslq  -8(%rbp), %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  1 14 8 is_stmt 0                # main.cpp:14:8
+  movq  %rax, -40(%rbp)
+  .loc  1 15 10 is_stmt 1               # main.cpp:15:10
+  movq  -16(%rbp), %rax
+  .loc  1 15 15 is_stmt 0               # main.cpp:15:15
+  movl  -8(%rbp), %ecx
+  .loc  1 15 20                         # main.cpp:15:20
+  addl  $1, %ecx
+  .loc  1 15 10                         # main.cpp:15:10
+  movslq  %ecx, %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  1 15 8                          # main.cpp:15:8
+  movq  %rax, -32(%rbp)
+  .loc  1 16 10 is_stmt 1               # main.cpp:16:10
+  movq  -16(%rbp), %rax
+  .loc  1 16 15 is_stmt 0               # main.cpp:16:15
+  movl  -8(%rbp), %ecx
+  .loc  1 16 20                         # main.cpp:16:20
+  addl  $2, %ecx
+  .loc  1 16 10                         # main.cpp:16:10
+  movslq  %ecx, %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  1 16 8                          # main.cpp:16:8
+  movq  %rax, -24(%rbp)
+  .loc  1 18 10 is_stmt 1               # main.cpp:18:10
+  movq  -16(%rbp), %rax
+  .loc  1 18 15 is_stmt 0               # main.cpp:18:15
+  movl  -8(%rbp), %ecx
+  .loc  1 18 20                         # main.cpp:18:20
+  addl  $3, %ecx
+  .loc  1 18 10                         # main.cpp:18:10
+  movslq  %ecx, %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  1 18 8                          # main.cpp:18:8
+  movq  %rax, -40(%rbp)
+  .loc  1 19 10 is_stmt 1               # main.cpp:19:10
+  movq  -16(%rbp), %rax
+  .loc  1 19 15 is_stmt 0               # main.cpp:19:15
+  movl  -8(%rbp), %ecx
+  .loc  1 19 20                         # main.cpp:19:20
+  addl  $4, %ecx
+  .loc  1 19 10                         # main.cpp:19:10
+  movslq  %ecx, %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  1 19 8                          # main.cpp:19:8
+  movq  %rax, -32(%rbp)
+  .loc  1 20 3 is_stmt 1                # main.cpp:20:3
+  xorl  %eax, %eax
+  popq  %rbp
+  .cfi_def_cfa %rsp, 8
+  retq
+.Ltmp1:
+.Lfunc_end0:
+  .size main, .Lfunc_end0-main
+  .cfi_endproc
+                                        # -- End function
+  .section  .debug_types.dwo,"e",@progbits
+  .long .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
+.Ldebug_info_dwo_start0:
+  .short  4                               # DWARF version number
+  .long 0                               # Offset Into Abbrev. Section
+  .byte 8                               # Address Size (in bytes)
+  .quad 7448148824980338162             # Type Signature
+  .long 30                              # Type DIE Offset
+  .byte 1                               # Abbrev [1] 0x17:0x33 DW_TAG_type_unit
+  .short  33                              # DW_AT_language
+  .long 0                               # DW_AT_stmt_list
+  .byte 2                               # Abbrev [2] 0x1e:0x22 DW_TAG_structure_type
+  .byte 5                               # DW_AT_calling_convention
+  .byte 9                               # DW_AT_name
+  .byte 24                              # DW_AT_byte_size
+  .byte 1                               # DW_AT_decl_file
+  .byte 1                               # DW_AT_decl_line
+  .byte 3                               # Abbrev [3] 0x24:0x9 DW_TAG_member
+  .byte 6                               # DW_AT_name
+  .long 64                              # DW_AT_type
+  .byte 1                               # DW_AT_decl_file
+  .byte 2                               # DW_AT_decl_line
+  .byte 0                               # DW_AT_data_member_location
+  .byte 3                               # Abbrev [3] 0x2d:0x9 DW_TAG_member
+  .byte 7                               # DW_AT_name
+  .long 64                              # DW_AT_type
+  .byte 1                               # DW_AT_decl_file
+  .byte 3                               # DW_AT_decl_line
+  .byte 8                               # DW_AT_data_member_location
+  .byte 3                               # Abbrev [3] 0x36:0x9 DW_TAG_member
+  .byte 8                               # DW_AT_name
+  .long 64                              # DW_AT_type
+  .byte 1                               # DW_AT_decl_file
+  .byte 4                               # DW_AT_decl_line
+  .byte 16                              # DW_AT_data_member_location
+  .byte 0                               # End Of Children Mark
+  .byte 4                               # Abbrev [4] 0x40:0x5 DW_TAG_pointer_type
+  .long 69                              # DW_AT_type
+  .byte 5                               # Abbrev [5] 0x45:0x4 DW_TAG_base_type
+  .byte 4                               # DW_AT_name
+  .byte 6                               # DW_AT_encoding
+  .byte 1                               # DW_AT_byte_size
+  .byte 0                               # End Of Children Mark
+.Ldebug_info_dwo_end0:
+  .long .Ldebug_info_dwo_end1-.Ldebug_info_dwo_start1 # Length of Unit
+.Ldebug_info_dwo_start1:
+  .short  4                               # DWARF version number
+  .long 0                               # Offset Into Abbrev. Section
+  .byte 8                               # Address Size (in bytes)
+  .quad 5322170643381124694             # Type Signature
+  .long 30                              # Type DIE Offset
+  .byte 1                               # Abbrev [1] 0x17:0x2a DW_TAG_type_unit
+  .short  33                              # DW_AT_language
+  .long 0                               # DW_AT_stmt_list
+  .byte 2                               # Abbrev [2] 0x1e:0x19 DW_TAG_structure_type
+  .byte 5                               # DW_AT_calling_convention
+  .byte 11                              # DW_AT_name
+  .byte 16                              # DW_AT_byte_size
+  .byte 1                               # DW_AT_decl_file
+  .byte 7                               # DW_AT_decl_line
+  .byte 3                               # Abbrev [3] 0x24:0x9 DW_TAG_member
+  .byte 6                               # DW_AT_name
+  .long 55                              # DW_AT_type
+  .byte 1                               # DW_AT_decl_file
+  .byte 8                               # DW_AT_decl_line
+  .byte 0                               # DW_AT_data_member_location
+  .byte 3                               # Abbrev [3] 0x2d:0x9 DW_TAG_member
+  .byte 7                               # DW_AT_name
+  .long 55                              # DW_AT_type
+  .byte 1                               # DW_AT_decl_file
+  .byte 9                               # DW_AT_decl_line
+  .byte 8                               # DW_AT_data_member_location
+  .byte 0                               # End Of Children Mark
+  .byte 4                               # Abbrev [4] 0x37:0x5 DW_TAG_pointer_type
+  .long 60                              # DW_AT_type
+  .byte 5                               # Abbrev [5] 0x3c:0x4 DW_TAG_base_type
+  .byte 4                               # DW_AT_name
+  .byte 6                               # DW_AT_encoding
+  .byte 1                               # DW_AT_byte_size
+  .byte 0                               # End Of Children Mark
+.Ldebug_info_dwo_end1:
+  .section  .debug_abbrev,"",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 0                               # DW_CHILDREN_no
+  .byte 16                              # DW_AT_stmt_list
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 27                              # DW_AT_comp_dir
+  .byte 14                              # DW_FORM_strp
+  .ascii  "\264B"                         # DW_AT_GNU_pubnames
+  .byte 25                              # DW_FORM_flag_present
+  .ascii  "\260B"                         # DW_AT_GNU_dwo_name
+  .byte 14                              # DW_FORM_strp
+  .ascii  "\261B"                         # DW_AT_GNU_dwo_id
+  .byte 7                               # DW_FORM_data8
+  .byte 17                              # DW_AT_low_pc
+  .byte 1                               # DW_FORM_addr
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .ascii  "\263B"                         # DW_AT_GNU_addr_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_info,"",@progbits
+.Lcu_begin0:
+  .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+  .short  4                               # DWARF version number
+  .long .debug_abbrev                   # Offset Into Abbrev. Section
+  .byte 8                               # Address Size (in bytes)
+  .byte 1                               # Abbrev [1] 0xb:0x25 DW_TAG_compile_unit
+  .long .Lline_table_start0             # DW_AT_stmt_list
+  .long .Lskel_string0                  # DW_AT_comp_dir
+                                        # DW_AT_GNU_pubnames
+  .long .Lskel_string1                  # DW_AT_GNU_dwo_name
+  .quad 4780348136649610820             # DW_AT_GNU_dwo_id
+  .quad .Lfunc_begin0                   # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .long .Laddr_table_base0              # DW_AT_GNU_addr_base
+.Ldebug_info_end0:
+  .section  .debug_str,"MS",@progbits,1
+.Lskel_string0:
+  .asciz  "." # string offset=0
+.Lskel_string1:
+  .asciz  "main.dwo"                      # string offset=38
+  .section  .debug_str.dwo,"eMS",@progbits,1
+.Linfo_string0:
+  .asciz  "main"                          # string offset=0
+.Linfo_string1:
+  .asciz  "int"                           # string offset=5
+.Linfo_string2:
+  .asciz  "argc"                          # string offset=9
+.Linfo_string3:
+  .asciz  "argv"                          # string offset=14
+.Linfo_string4:
+  .asciz  "char"                          # string offset=19
+.Linfo_string5:
+  .asciz  "f"                             # string offset=24
+.Linfo_string6:
+  .asciz  "c1"                            # string offset=26
+.Linfo_string7:
+  .asciz  "c2"                            # string offset=29
+.Linfo_string8:
+  .asciz  "c3"                            # string offset=32
+.Linfo_string9:
+  .asciz  "Foo"                           # string offset=35
+.Linfo_string10:
+  .asciz  "f2"                            # string offset=39
+.Linfo_string11:
+  .asciz  "Foo2"                          # string offset=42
+.Linfo_string12:
+  .asciz  "clang version 15.0.0"      # string offset=47
+.Linfo_string13:
+  .asciz  "main.cpp"                      # string offset=68
+.Linfo_string14:
+  .asciz  "main.dwo"                      # string offset=77
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 0
+  .long 5
+  .long 9
+  .long 14
+  .long 19
+  .long 24
+  .long 26
+  .long 29
+  .long 32
+  .long 35
+  .long 39
+  .long 42
+  .long 47
+  .long 68
+  .long 77
+  .section  .debug_info.dwo,"e",@progbits
+  .long .Ldebug_info_dwo_end2-.Ldebug_info_dwo_start2 # Length of Unit
+.Ldebug_info_dwo_start2:
+  .short  4                               # DWARF version number
+  .long 0                               # Offset Into Abbrev. Section
+  .byte 8                               # Address Size (in bytes)
+  .byte 6                               # Abbrev [6] 0xb:0x6f DW_TAG_compile_unit
+  .byte 12                              # DW_AT_producer
+  .short  33                              # DW_AT_language
+  .byte 13                              # DW_AT_name
+  .byte 14                              # DW_AT_GNU_dwo_name
+  .quad 4780348136649610820             # DW_AT_GNU_dwo_id
+  .byte 7                               # Abbrev [7] 0x19:0x3c DW_TAG_subprogram
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .byte 1                               # DW_AT_frame_base
+  .byte 86
+  .byte 0                               # DW_AT_name
+  .byte 1                               # DW_AT_decl_file
+  .byte 12                              # DW_AT_decl_line
+  .long 85                              # DW_AT_type
+                                        # DW_AT_external
+  .byte 8                               # Abbrev [8] 0x28:0xb DW_TAG_formal_parameter
+  .byte 2                               # DW_AT_location
+  .byte 145
+  .byte 120
+  .byte 2                               # DW_AT_name
+  .byte 1                               # DW_AT_decl_file
+  .byte 12                              # DW_AT_decl_line
+  .long 85                              # DW_AT_type
+  .byte 8                               # Abbrev [8] 0x33:0xb DW_TAG_formal_parameter
+  .byte 2                               # DW_AT_location
+  .byte 145
+  .byte 112
+  .byte 3                               # DW_AT_name
+  .byte 1                               # DW_AT_decl_file
+  .byte 12                              # DW_AT_decl_line
+  .long 89                              # DW_AT_type
+  .byte 9                               # Abbrev [9] 0x3e:0xb DW_TAG_variable
+  .byte 2                               # DW_AT_location
+  .byte 145
+  .byte 88
+  .byte 5                               # DW_AT_name
+  .byte 1                               # DW_AT_decl_file
+  .byte 13                              # DW_AT_decl_line
+  .long 103                             # DW_AT_type
+  .byte 9                               # Abbrev [9] 0x49:0xb DW_TAG_variable
+  .byte 2                               # DW_AT_location
+  .byte 145
+  .byte 72
+  .byte 10                              # DW_AT_name
+  .byte 1                               # DW_AT_decl_file
+  .byte 17                              # DW_AT_decl_line
+  .long 112                             # DW_AT_type
+  .byte 0                               # End Of Children Mark
+  .byte 5                               # Abbrev [5] 0x55:0x4 DW_TAG_base_type
+  .byte 1                               # DW_AT_name
+  .byte 5                               # DW_AT_encoding
+  .byte 4                               # DW_AT_byte_size
+  .byte 4                               # Abbrev [4] 0x59:0x5 DW_TAG_pointer_type
+  .long 94                              # DW_AT_type
+  .byte 4                               # Abbrev [4] 0x5e:0x5 DW_TAG_pointer_type
+  .long 99                              # DW_AT_type
+  .byte 5                               # Abbrev [5] 0x63:0x4 DW_TAG_base_type
+  .byte 4                               # DW_AT_name
+  .byte 6                               # DW_AT_encoding
+  .byte 1                               # DW_AT_byte_size
+  .byte 10                              # Abbrev [10] 0x67:0x9 DW_TAG_structure_type
+                                        # DW_AT_declaration
+  .quad 7448148824980338162             # DW_AT_signature
+  .byte 10                              # Abbrev [10] 0x70:0x9 DW_TAG_structure_type
+                                        # DW_AT_declaration
+  .quad 5322170643381124694             # DW_AT_signature
+  .byte 0                               # End Of Children Mark
+.Ldebug_info_dwo_end2:
+  .section  .debug_abbrev.dwo,"e",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 65                              # DW_TAG_type_unit
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 19                              # DW_AT_language
+  .byte 5                               # DW_FORM_data2
+  .byte 16                              # DW_AT_stmt_list
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 2                               # Abbreviation Code
+  .byte 19                              # DW_TAG_structure_type
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 54                              # DW_AT_calling_convention
+  .byte 11                              # DW_FORM_data1
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 11                              # DW_AT_byte_size
+  .byte 11                              # DW_FORM_data1
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 3                               # Abbreviation Code
+  .byte 13                              # DW_TAG_member
+  .byte 0                               # DW_CHILDREN_no
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 56                              # DW_AT_data_member_location
+  .byte 11                              # DW_FORM_data1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 4                               # Abbreviation Code
+  .byte 15                              # DW_TAG_pointer_type
+  .byte 0                               # DW_CHILDREN_no
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 5                               # Abbreviation Code
+  .byte 36                              # DW_TAG_base_type
+  .byte 0                               # DW_CHILDREN_no
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 62                              # DW_AT_encoding
+  .byte 11                              # DW_FORM_data1
+  .byte 11                              # DW_AT_byte_size
+  .byte 11                              # DW_FORM_data1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 6                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 37                              # DW_AT_producer
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 19                              # DW_AT_language
+  .byte 5                               # DW_FORM_data2
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .ascii  "\260B"                         # DW_AT_GNU_dwo_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .ascii  "\261B"                         # DW_AT_GNU_dwo_id
+  .byte 7                               # DW_FORM_data8
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 7                               # Abbreviation Code
+  .byte 46                              # DW_TAG_subprogram
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 17                              # DW_AT_low_pc
+  .ascii  "\201>"                         # DW_FORM_GNU_addr_index
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 64                              # DW_AT_frame_base
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 63                              # DW_AT_external
+  .byte 25                              # DW_FORM_flag_present
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 8                               # Abbreviation Code
+  .byte 5                               # DW_TAG_formal_parameter
+  .byte 0                               # DW_CHILDREN_no
+  .byte 2                               # DW_AT_location
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 9                               # Abbreviation Code
+  .byte 52                              # DW_TAG_variable
+  .byte 0                               # DW_CHILDREN_no
+  .byte 2                               # DW_AT_location
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .ascii  "\202>"                         # DW_FORM_GNU_str_index
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 10                              # Abbreviation Code
+  .byte 19                              # DW_TAG_structure_type
+  .byte 0                               # DW_CHILDREN_no
+  .byte 60                              # DW_AT_declaration
+  .byte 25                              # DW_FORM_flag_present
+  .byte 105                             # DW_AT_signature
+  .byte 32                              # DW_FORM_ref_sig8
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_line.dwo,"e",@progbits
+.Ltmp2:
+  .long .Ldebug_line_end0-.Ldebug_line_start0 # unit length
+.Ldebug_line_start0:
+  .short  4
+  .long .Lprologue_end0-.Lprologue_start0
+.Lprologue_start0:
+  .byte 1
+  .byte 1
+  .byte 1
+  .byte -5
+  .byte 14
+  .byte 1
+  .byte 0
+  .ascii  "main.cpp"
+  .byte 0
+  .byte 0
+  .byte 0
+  .byte 0
+  .byte 0
+.Lprologue_end0:
+.Ldebug_line_end0:
+  .section  .debug_addr,"",@progbits
+.Laddr_table_base0:
+  .quad .Lfunc_begin0
+  .section  .debug_gnu_pubnames,"",@progbits
+  .long .LpubNames_end0-.LpubNames_start0 # Length of Public Names Info
+.LpubNames_start0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 48                              # Compilation Unit Length
+  .long 25                              # DIE offset
+  .byte 48                              # Attributes: FUNCTION, EXTERNAL
+  .asciz  "main"                          # External Name
+  .long 0                               # End Mark
+.LpubNames_end0:
+  .section  .debug_gnu_pubtypes,"",@progbits
+  .long .LpubTypes_end0-.LpubTypes_start0 # Length of Public Types Info
+.LpubTypes_start0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 48                              # Compilation Unit Length
+  .long 103                             # DIE offset
+  .byte 16                              # Attributes: TYPE, EXTERNAL
+  .asciz  "Foo"                           # External Name
+  .long 112                             # DIE offset
+  .byte 16                              # Attributes: TYPE, EXTERNAL
+  .asciz  "Foo2"                          # External Name
+  .long 85                              # DIE offset
+  .byte 144                             # Attributes: TYPE, STATIC
+  .asciz  "int"                           # External Name
+  .long 99                              # DIE offset
+  .byte 144                             # Attributes: TYPE, STATIC
+  .asciz  "char"                          # External Name
+  .long 0                               # End Mark
+.LpubTypes_end0:
+  .ident  "clang version 15.0.0"
+  .section  ".note.GNU-stack","",@progbits
+  .addrsig
+  .section  .debug_line,"",@progbits
+.Lline_table_start0:

bolt/test/X86/Inputs/dwarf5-ftypes-split-dwarf.s

+# clang++ main.cpp -g2 -gsplit-dwarf=split -gdwarf-5 -fdebug-types-section -S
+# struct Foo {
+#   char *c1;
+#   char *c2;
+#   char *c3;
+# };
+#
+# struct Foo2 {
+#   char *c1;
+#   char *c2;
+# };
+#
+# int main(int argc, char *argv[]) {
+#   Foo f;
+#   f.c1 = argv[argc];
+#   f.c2 = argv[argc + 1];
+#   f.c3 = argv[argc + 2];
+#   Foo2 f2;
+#   f.c1 = argv[argc + 3];
+#   f.c2 = argv[argc + 4];
+#   return 0;
+# }
+
+  .text
+  .file "main.cpp"
+  .globl  main                            # -- Begin function main
+  .p2align  4, 0x90
+  .type main,@function
+main:                                   # @main
+.Lfunc_begin0:
+  .file 0 "." "main.cpp" md5 0xa832f464c853be0f9c52da29cd913807
+  .loc  0 12 0                          # main.cpp:12:0
+  .cfi_startproc
+# %bb.0:                                # %entry
+  pushq %rbp
+  .cfi_def_cfa_offset 16
+  .cfi_offset %rbp, -16
+  movq  %rsp, %rbp
+  .cfi_def_cfa_register %rbp
+  movl  $0, -4(%rbp)
+  movl  %edi, -8(%rbp)
+  movq  %rsi, -16(%rbp)
+.Ltmp0:
+  .loc  0 14 10 prologue_end            # main.cpp:14:10
+  movq  -16(%rbp), %rax
+  movslq  -8(%rbp), %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  0 14 8 is_stmt 0                # main.cpp:14:8
+  movq  %rax, -40(%rbp)
+  .loc  0 15 10 is_stmt 1               # main.cpp:15:10
+  movq  -16(%rbp), %rax
+  .loc  0 15 15 is_stmt 0               # main.cpp:15:15
+  movl  -8(%rbp), %ecx
+  .loc  0 15 20                         # main.cpp:15:20
+  addl  $1, %ecx
+  .loc  0 15 10                         # main.cpp:15:10
+  movslq  %ecx, %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  0 15 8                          # main.cpp:15:8
+  movq  %rax, -32(%rbp)
+  .loc  0 16 10 is_stmt 1               # main.cpp:16:10
+  movq  -16(%rbp), %rax
+  .loc  0 16 15 is_stmt 0               # main.cpp:16:15
+  movl  -8(%rbp), %ecx
+  .loc  0 16 20                         # main.cpp:16:20
+  addl  $2, %ecx
+  .loc  0 16 10                         # main.cpp:16:10
+  movslq  %ecx, %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  0 16 8                          # main.cpp:16:8
+  movq  %rax, -24(%rbp)
+  .loc  0 18 10 is_stmt 1               # main.cpp:18:10
+  movq  -16(%rbp), %rax
+  .loc  0 18 15 is_stmt 0               # main.cpp:18:15
+  movl  -8(%rbp), %ecx
+  .loc  0 18 20                         # main.cpp:18:20
+  addl  $3, %ecx
+  .loc  0 18 10                         # main.cpp:18:10
+  movslq  %ecx, %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  0 18 8                          # main.cpp:18:8
+  movq  %rax, -40(%rbp)
+  .loc  0 19 10 is_stmt 1               # main.cpp:19:10
+  movq  -16(%rbp), %rax
+  .loc  0 19 15 is_stmt 0               # main.cpp:19:15
+  movl  -8(%rbp), %ecx
+  .loc  0 19 20                         # main.cpp:19:20
+  addl  $4, %ecx
+  .loc  0 19 10                         # main.cpp:19:10
+  movslq  %ecx, %rcx
+  movq  (%rax,%rcx,8), %rax
+  .loc  0 19 8                          # main.cpp:19:8
+  movq  %rax, -32(%rbp)
+  .loc  0 20 3 is_stmt 1                # main.cpp:20:3
+  xorl  %eax, %eax
+  popq  %rbp
+  .cfi_def_cfa %rsp, 8
+  retq
+.Ltmp1:
+.Lfunc_end0:
+  .size main, .Lfunc_end0-main
+  .cfi_endproc
+                                        # -- End function
+  .section  .debug_info.dwo,"e",@progbits
+  .long .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
+.Ldebug_info_dwo_start0:
+  .short  5                               # DWARF version number
+  .byte 6                               # DWARF Unit Type
+  .byte 8                               # Address Size (in bytes)
+  .long 0                               # Offset Into Abbrev. Section
+  .quad 7448148824980338162             # Type Signature
+  .long 31                              # Type DIE Offset
+  .byte 1                               # Abbrev [1] 0x18:0x33 DW_TAG_type_unit
+  .short  33                              # DW_AT_language
+  .long 0                               # DW_AT_stmt_list
+  .byte 2                               # Abbrev [2] 0x1f:0x22 DW_TAG_structure_type
+  .byte 5                               # DW_AT_calling_convention
+  .byte 9                               # DW_AT_name
+  .byte 24                              # DW_AT_byte_size
+  .byte 0                               # DW_AT_decl_file
+  .byte 1                               # DW_AT_decl_line
+  .byte 3                               # Abbrev [3] 0x25:0x9 DW_TAG_member
+  .byte 6                               # DW_AT_name
+  .long 65                              # DW_AT_type
+  .byte 0                               # DW_AT_decl_file
+  .byte 2                               # DW_AT_decl_line
+  .byte 0                               # DW_AT_data_member_location
+  .byte 3                               # Abbrev [3] 0x2e:0x9 DW_TAG_member
+  .byte 7                               # DW_AT_name
+  .long 65                              # DW_AT_type
+  .byte 0                               # DW_AT_decl_file
+  .byte 3                               # DW_AT_decl_line
+  .byte 8                               # DW_AT_data_member_location
+  .byte 3                               # Abbrev [3] 0x37:0x9 DW_TAG_member
+  .byte 8                               # DW_AT_name
+  .long 65                              # DW_AT_type
+  .byte 0                               # DW_AT_decl_file
+  .byte 4                               # DW_AT_decl_line
+  .byte 16                              # DW_AT_data_member_location
+  .byte 0                               # End Of Children Mark
+  .byte 4                               # Abbrev [4] 0x41:0x5 DW_TAG_pointer_type
+  .long 70                              # DW_AT_type
+  .byte 5                               # Abbrev [5] 0x46:0x4 DW_TAG_base_type
+  .byte 4                               # DW_AT_name
+  .byte 6                               # DW_AT_encoding
+  .byte 1                               # DW_AT_byte_size
+  .byte 0                               # End Of Children Mark
+.Ldebug_info_dwo_end0:
+  .long .Ldebug_info_dwo_end1-.Ldebug_info_dwo_start1 # Length of Unit
+.Ldebug_info_dwo_start1:
+  .short  5                               # DWARF version number
+  .byte 6                               # DWARF Unit Type
+  .byte 8                               # Address Size (in bytes)
+  .long 0                               # Offset Into Abbrev. Section
+  .quad 5322170643381124694             # Type Signature
+  .long 31                              # Type DIE Offset
+  .byte 1                               # Abbrev [1] 0x18:0x2a DW_TAG_type_unit
+  .short  33                              # DW_AT_language
+  .long 0                               # DW_AT_stmt_list
+  .byte 2                               # Abbrev [2] 0x1f:0x19 DW_TAG_structure_type
+  .byte 5                               # DW_AT_calling_convention
+  .byte 11                              # DW_AT_name
+  .byte 16                              # DW_AT_byte_size
+  .byte 0                               # DW_AT_decl_file
+  .byte 7                               # DW_AT_decl_line
+  .byte 3                               # Abbrev [3] 0x25:0x9 DW_TAG_member
+  .byte 6                               # DW_AT_name
+  .long 56                              # DW_AT_type
+  .byte 0                               # DW_AT_decl_file
+  .byte 8                               # DW_AT_decl_line
+  .byte 0                               # DW_AT_data_member_location
+  .byte 3                               # Abbrev [3] 0x2e:0x9 DW_TAG_member
+  .byte 7                               # DW_AT_name
+  .long 56                              # DW_AT_type
+  .byte 0                               # DW_AT_decl_file
+  .byte 9                               # DW_AT_decl_line
+  .byte 8                               # DW_AT_data_member_location
+  .byte 0                               # End Of Children Mark
+  .byte 4                               # Abbrev [4] 0x38:0x5 DW_TAG_pointer_type
+  .long 61                              # DW_AT_type
+  .byte 5                               # Abbrev [5] 0x3d:0x4 DW_TAG_base_type
+  .byte 4                               # DW_AT_name
+  .byte 6                               # DW_AT_encoding
+  .byte 1                               # DW_AT_byte_size
+  .byte 0                               # End Of Children Mark
+.Ldebug_info_dwo_end1:
+  .section  .debug_abbrev,"",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 74                              # DW_TAG_skeleton_unit
+  .byte 0                               # DW_CHILDREN_no
+  .byte 16                              # DW_AT_stmt_list
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 114                             # DW_AT_str_offsets_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 27                              # DW_AT_comp_dir
+  .byte 37                              # DW_FORM_strx1
+  .ascii  "\264B"                         # DW_AT_GNU_pubnames
+  .byte 25                              # DW_FORM_flag_present
+  .byte 118                             # DW_AT_dwo_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 17                              # DW_AT_low_pc
+  .byte 27                              # DW_FORM_addrx
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 115                             # DW_AT_addr_base
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_info,"",@progbits
+.Lcu_begin0:
+  .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+  .short  5                               # DWARF version number
+  .byte 4                               # DWARF Unit Type
+  .byte 8                               # Address Size (in bytes)
+  .long .debug_abbrev                   # Offset Into Abbrev. Section
+  .quad 4780348136649610820
+  .byte 1                               # Abbrev [1] 0x14:0x14 DW_TAG_skeleton_unit
+  .long .Lline_table_start0             # DW_AT_stmt_list
+  .long .Lstr_offsets_base0             # DW_AT_str_offsets_base
+  .byte 0                               # DW_AT_comp_dir
+                                        # DW_AT_GNU_pubnames
+  .byte 1                               # DW_AT_dwo_name
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .long .Laddr_table_base0              # DW_AT_addr_base
+.Ldebug_info_end0:
+  .section  .debug_str_offsets,"",@progbits
+  .long 12                              # Length of String Offsets Set
+  .short  5
+  .short  0
+.Lstr_offsets_base0:
+  .section  .debug_str,"MS",@progbits,1
+.Lskel_string0:
+  .asciz  "." # string offset=0
+.Lskel_string1:
+  .asciz  "main.dwo"                      # string offset=38
+  .section  .debug_str_offsets,"",@progbits
+  .long .Lskel_string0
+  .long .Lskel_string1
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 64                              # Length of String Offsets Set
+  .short  5
+  .short  0
+  .section  .debug_str.dwo,"eMS",@progbits,1
+.Linfo_string0:
+  .asciz  "main"                          # string offset=0
+.Linfo_string1:
+  .asciz  "int"                           # string offset=5
+.Linfo_string2:
+  .asciz  "argc"                          # string offset=9
+.Linfo_string3:
+  .asciz  "argv"                          # string offset=14
+.Linfo_string4:
+  .asciz  "char"                          # string offset=19
+.Linfo_string5:
+  .asciz  "f"                             # string offset=24
+.Linfo_string6:
+  .asciz  "c1"                            # string offset=26
+.Linfo_string7:
+  .asciz  "c2"                            # string offset=29
+.Linfo_string8:
+  .asciz  "c3"                            # string offset=32
+.Linfo_string9:
+  .asciz  "Foo"                           # string offset=35
+.Linfo_string10:
+  .asciz  "f2"                            # string offset=39
+.Linfo_string11:
+  .asciz  "Foo2"                          # string offset=42
+.Linfo_string12:
+  .asciz  "clang version 15.0.0"      # string offset=47
+.Linfo_string13:
+  .asciz  "main.cpp"                      # string offset=68
+.Linfo_string14:
+  .asciz  "main.dwo"                      # string offset=77
+  .section  .debug_str_offsets.dwo,"e",@progbits
+  .long 0
+  .long 5
+  .long 9
+  .long 14
+  .long 19
+  .long 24
+  .long 26
+  .long 29
+  .long 32
+  .long 35
+  .long 39
+  .long 42
+  .long 47
+  .long 68
+  .long 77
+  .section  .debug_info.dwo,"e",@progbits
+  .long .Ldebug_info_dwo_end2-.Ldebug_info_dwo_start2 # Length of Unit
+.Ldebug_info_dwo_start2:
+  .short  5                               # DWARF version number
+  .byte 5                               # DWARF Unit Type
+  .byte 8                               # Address Size (in bytes)
+  .long 0                               # Offset Into Abbrev. Section
+  .quad 4780348136649610820
+  .byte 6                               # Abbrev [6] 0x14:0x67 DW_TAG_compile_unit
+  .byte 12                              # DW_AT_producer
+  .short  33                              # DW_AT_language
+  .byte 13                              # DW_AT_name
+  .byte 14                              # DW_AT_dwo_name
+  .byte 7                               # Abbrev [7] 0x1a:0x3c DW_TAG_subprogram
+  .byte 0                               # DW_AT_low_pc
+  .long .Lfunc_end0-.Lfunc_begin0       # DW_AT_high_pc
+  .byte 1                               # DW_AT_frame_base
+  .byte 86
+  .byte 0                               # DW_AT_name
+  .byte 0                               # DW_AT_decl_file
+  .byte 12                              # DW_AT_decl_line
+  .long 86                              # DW_AT_type
+                                        # DW_AT_external
+  .byte 8                               # Abbrev [8] 0x29:0xb DW_TAG_formal_parameter
+  .byte 2                               # DW_AT_location
+  .byte 145
+  .byte 120
+  .byte 2                               # DW_AT_name
+  .byte 0                               # DW_AT_decl_file
+  .byte 12                              # DW_AT_decl_line
+  .long 86                              # DW_AT_type
+  .byte 8                               # Abbrev [8] 0x34:0xb DW_TAG_formal_parameter
+  .byte 2                               # DW_AT_location
+  .byte 145
+  .byte 112
+  .byte 3                               # DW_AT_name
+  .byte 0                               # DW_AT_decl_file
+  .byte 12                              # DW_AT_decl_line
+  .long 90                              # DW_AT_type
+  .byte 9                               # Abbrev [9] 0x3f:0xb DW_TAG_variable
+  .byte 2                               # DW_AT_location
+  .byte 145
+  .byte 88
+  .byte 5                               # DW_AT_name
+  .byte 0                               # DW_AT_decl_file
+  .byte 13                              # DW_AT_decl_line
+  .long 104                             # DW_AT_type
+  .byte 9                               # Abbrev [9] 0x4a:0xb DW_TAG_variable
+  .byte 2                               # DW_AT_location
+  .byte 145
+  .byte 72
+  .byte 10                              # DW_AT_name
+  .byte 0                               # DW_AT_decl_file
+  .byte 17                              # DW_AT_decl_line
+  .long 113                             # DW_AT_type
+  .byte 0                               # End Of Children Mark
+  .byte 5                               # Abbrev [5] 0x56:0x4 DW_TAG_base_type
+  .byte 1                               # DW_AT_name
+  .byte 5                               # DW_AT_encoding
+  .byte 4                               # DW_AT_byte_size
+  .byte 4                               # Abbrev [4] 0x5a:0x5 DW_TAG_pointer_type
+  .long 95                              # DW_AT_type
+  .byte 4                               # Abbrev [4] 0x5f:0x5 DW_TAG_pointer_type
+  .long 100                             # DW_AT_type
+  .byte 5                               # Abbrev [5] 0x64:0x4 DW_TAG_base_type
+  .byte 4                               # DW_AT_name
+  .byte 6                               # DW_AT_encoding
+  .byte 1                               # DW_AT_byte_size
+  .byte 10                              # Abbrev [10] 0x68:0x9 DW_TAG_structure_type
+                                        # DW_AT_declaration
+  .quad 7448148824980338162             # DW_AT_signature
+  .byte 10                              # Abbrev [10] 0x71:0x9 DW_TAG_structure_type
+                                        # DW_AT_declaration
+  .quad 5322170643381124694             # DW_AT_signature
+  .byte 0                               # End Of Children Mark
+.Ldebug_info_dwo_end2:
+  .section  .debug_abbrev.dwo,"e",@progbits
+  .byte 1                               # Abbreviation Code
+  .byte 65                              # DW_TAG_type_unit
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 19                              # DW_AT_language
+  .byte 5                               # DW_FORM_data2
+  .byte 16                              # DW_AT_stmt_list
+  .byte 23                              # DW_FORM_sec_offset
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 2                               # Abbreviation Code
+  .byte 19                              # DW_TAG_structure_type
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 54                              # DW_AT_calling_convention
+  .byte 11                              # DW_FORM_data1
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 11                              # DW_AT_byte_size
+  .byte 11                              # DW_FORM_data1
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 3                               # Abbreviation Code
+  .byte 13                              # DW_TAG_member
+  .byte 0                               # DW_CHILDREN_no
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 56                              # DW_AT_data_member_location
+  .byte 11                              # DW_FORM_data1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 4                               # Abbreviation Code
+  .byte 15                              # DW_TAG_pointer_type
+  .byte 0                               # DW_CHILDREN_no
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 5                               # Abbreviation Code
+  .byte 36                              # DW_TAG_base_type
+  .byte 0                               # DW_CHILDREN_no
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 62                              # DW_AT_encoding
+  .byte 11                              # DW_FORM_data1
+  .byte 11                              # DW_AT_byte_size
+  .byte 11                              # DW_FORM_data1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 6                               # Abbreviation Code
+  .byte 17                              # DW_TAG_compile_unit
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 37                              # DW_AT_producer
+  .byte 37                              # DW_FORM_strx1
+  .byte 19                              # DW_AT_language
+  .byte 5                               # DW_FORM_data2
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 118                             # DW_AT_dwo_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 7                               # Abbreviation Code
+  .byte 46                              # DW_TAG_subprogram
+  .byte 1                               # DW_CHILDREN_yes
+  .byte 17                              # DW_AT_low_pc
+  .byte 27                              # DW_FORM_addrx
+  .byte 18                              # DW_AT_high_pc
+  .byte 6                               # DW_FORM_data4
+  .byte 64                              # DW_AT_frame_base
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 63                              # DW_AT_external
+  .byte 25                              # DW_FORM_flag_present
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 8                               # Abbreviation Code
+  .byte 5                               # DW_TAG_formal_parameter
+  .byte 0                               # DW_CHILDREN_no
+  .byte 2                               # DW_AT_location
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 9                               # Abbreviation Code
+  .byte 52                              # DW_TAG_variable
+  .byte 0                               # DW_CHILDREN_no
+  .byte 2                               # DW_AT_location
+  .byte 24                              # DW_FORM_exprloc
+  .byte 3                               # DW_AT_name
+  .byte 37                              # DW_FORM_strx1
+  .byte 58                              # DW_AT_decl_file
+  .byte 11                              # DW_FORM_data1
+  .byte 59                              # DW_AT_decl_line
+  .byte 11                              # DW_FORM_data1
+  .byte 73                              # DW_AT_type
+  .byte 19                              # DW_FORM_ref4
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 10                              # Abbreviation Code
+  .byte 19                              # DW_TAG_structure_type
+  .byte 0                               # DW_CHILDREN_no
+  .byte 60                              # DW_AT_declaration
+  .byte 25                              # DW_FORM_flag_present
+  .byte 105                             # DW_AT_signature
+  .byte 32                              # DW_FORM_ref_sig8
+  .byte 0                               # EOM(1)
+  .byte 0                               # EOM(2)
+  .byte 0                               # EOM(3)
+  .section  .debug_line.dwo,"e",@progbits
+.Ltmp2:
+  .long .Ldebug_line_end0-.Ldebug_line_start0 # unit length
+.Ldebug_line_start0:
+  .short  5
+  .byte 8
+  .byte 0
+  .long .Lprologue_end0-.Lprologue_start0
+.Lprologue_start0:
+  .byte 1
+  .byte 1
+  .byte 1
+  .byte -5
+  .byte 14
+  .byte 1
+  .byte 1
+  .byte 1
+  .byte 8
+  .byte 1
+  .ascii  "/home/ayermolo/local/tasks/T104766233"
+  .byte 0
+  .byte 3
+  .byte 1
+  .byte 8
+  .byte 2
+  .byte 15
+  .byte 5
+  .byte 30
+  .byte 1
+  .ascii  "main.cpp"
+  .byte 0
+  .byte 0
+  .byte 0xa8, 0x32, 0xf4, 0x64
+  .byte 0xc8, 0x53, 0xbe, 0x0f
+  .byte 0x9c, 0x52, 0xda, 0x29
+  .byte 0xcd, 0x91, 0x38, 0x07
+.Lprologue_end0:
+.Ldebug_line_end0:
+  .section  .debug_addr,"",@progbits
+  .long .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
+.Ldebug_addr_start0:
+  .short  5                               # DWARF version number
+  .byte 8                               # Address size
+  .byte 0                               # Segment selector size
+.Laddr_table_base0:
+  .quad .Lfunc_begin0
+.Ldebug_addr_end0:
+  .section  .debug_gnu_pubnames,"",@progbits
+  .long .LpubNames_end0-.LpubNames_start0 # Length of Public Names Info
+.LpubNames_start0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 40                              # Compilation Unit Length
+  .long 26                              # DIE offset
+  .byte 48                              # Attributes: FUNCTION, EXTERNAL
+  .asciz  "main"                          # External Name
+  .long 0                               # End Mark
+.LpubNames_end0:
+  .section  .debug_gnu_pubtypes,"",@progbits
+  .long .LpubTypes_end0-.LpubTypes_start0 # Length of Public Types Info
+.LpubTypes_start0:
+  .short  2                               # DWARF Version
+  .long .Lcu_begin0                     # Offset of Compilation Unit Info
+  .long 40                              # Compilation Unit Length
+  .long 104                             # DIE offset
+  .byte 16                              # Attributes: TYPE, EXTERNAL
+  .asciz  "Foo"                           # External Name
+  .long 113                             # DIE offset
+  .byte 16                              # Attributes: TYPE, EXTERNAL
+  .asciz  "Foo2"                          # External Name
+  .long 86                              # DIE offset
+  .byte 144                             # Attributes: TYPE, STATIC
+  .asciz  "int"                           # External Name
+  .long 100                             # DIE offset
+  .byte 144                             # Attributes: TYPE, STATIC
+  .asciz  "char"                          # External Name
+  .long 0                               # End Mark
+.LpubTypes_end0:
+  .ident  "clang version 15.0.0"
+  .section  ".note.GNU-stack","",@progbits
+  .addrsig
+  .section  .debug_line,"",@progbits
+.Lline_table_start0:

bolt/test/X86/dwarf4-ftypes-dwo-input-dwp-output.test

+# REQUIRES: system-linux
+; RUN: rm -rf %t
+; RUN: mkdir %t
+; RUN: cd %t
+; RUN: llvm-mc --split-dwarf-file=main.dwo --triple=x86_64-unknown-linux-gnu \
+; RUN: --filetype=obj %p/Inputs/dwarf4-ftypes-split-dwarf.s -o=main.o
+; RUN: %clang %cflags -gdwarf-4 -gsplit-dwarf=split main.o -o main.exe
+; RUN: llvm-dwarfdump --show-form --verbose --debug-types main.dwo | FileCheck -check-prefix=PRE-BOLT %s
+; RUN: llvm-bolt main.exe -o main.exe.bolt --update-debug-sections -write-dwp
+; RUN: llvm-dwarfdump --show-form --verbose --debug-types main.exe.bolt.dwp | FileCheck -check-prefix=BOLT %s
+; RUN: llvm-dwarfdump --show-form --verbose --debug-tu-index main.exe.bolt.dwp | FileCheck -check-prefix=BOLT-DWP-TU-INDEX %s
+
+; Test input into bolt a .dwo file with TU Index.
+; Make sure the output .dwp file has a type information.
+
+; PRE-BOLT: DW_TAG_type_unit
+; PRE-BOLT: DW_TAG_type_unit
+
+; PRE-BOLT-DWP-TU-INDEX: version = 2, units = 2, slots = 4
+; PRE-BOLT-DWP-TU-INDEX: Index Signature
+; PRE-BOLT-DWP-TU-INDEX: 0x675d23e4f33235f2
+; PRE-BOLT-DWP-TU-INDEX-NEXT: 0x49dc260088be7e56
+
+; BOLT: DW_TAG_type_unit
+; BOLT: DW_TAG_type_unit
+
+; BOLT-DWP-TU-INDEX: version = 2, units = 2, slots = 4
+; BOLT-DWP-TU-INDEX: Index Signature
+; BOLT-DWP-TU-INDEX: 0x675d23e4f33235f2
+; BOLT-DWP-TU-INDEX-NEXT: 0x49dc260088be7e56

bolt/test/X86/dwarf4-ftypes-dwp-input-dwo-output.test

+# REQUIRES: system-linux
+; RUN: rm -rf %t
+; RUN: mkdir %t
+; RUN: cd %t
+; RUN: llvm-mc --split-dwarf-file=main.dwo --triple=x86_64-unknown-linux-gnu \
+; RUN: --filetype=obj %p/Inputs/dwarf4-ftypes-split-dwarf.s -o=main.o
+; RUN: %clang %cflags -gdwarf-4 -gsplit-dwarf=split main.o -o main.exe
+; RUN: llvm-dwp -e main.exe -o main.exe.dwp
+; RUN: llvm-dwarfdump --show-form --verbose --debug-types main.exe.dwp | FileCheck -check-prefix=PRE-BOLT %s
+; RUN: llvm-dwarfdump --show-form --verbose --debug-tu-index main.exe.dwp | FileCheck -check-prefix=PRE-BOLT-DWP-TU-INDEX %s
+; RUN: llvm-bolt main.exe -o main.exe.bolt --update-debug-sections
+; RUN: llvm-dwarfdump --show-form --verbose --debug-types main.dwo.dwo | FileCheck -check-prefix=BOLT %s
+
+; Test input into bolt a DWP file with TU Index.
+; Make sure output in the .dwo files has type information.
+
+; PRE-BOLT: DW_TAG_type_unit
+; PRE-BOLT: DW_TAG_type_unit
+
+; PRE-BOLT-DWP-TU-INDEX: version = 2, units = 2, slots = 4
+; PRE-BOLT-DWP-TU-INDEX: Index Signature
+; PRE-BOLT-DWP-TU-INDEX: 0x675d23e4f33235f2
+; PRE-BOLT-DWP-TU-INDEX-NEXT: 0x49dc260088be7e56
+
+; BOLT: DW_TAG_type_unit
+; BOLT: DW_TAG_type_unit

bolt/test/X86/dwarf4-ftypes-dwp-input-dwp-output.test

+# REQUIRES: system-linux
+; RUN: rm -rf %t
+; RUN: mkdir %t
+; RUN: cd %t
+; RUN: llvm-mc --split-dwarf-file=main.dwo --triple=x86_64-unknown-linux-gnu \
+; RUN: --filetype=obj %p/Inputs/dwarf4-ftypes-split-dwarf.s -o=main.o
+; RUN: %clang %cflags -gdwarf-4 -gsplit-dwarf=split main.o -o main.exe
+; RUN: llvm-dwp -e main.exe -o main.exe.dwp
+; RUN: llvm-dwarfdump --show-form --verbose --debug-types main.exe.dwp | FileCheck -check-prefix=PRE-BOLT %s
+; RUN: llvm-dwarfdump --show-form --verbose --debug-tu-index main.exe.dwp | FileCheck -check-prefix=PRE-BOLT-DWP-TU-INDEX %s
+; RUN: llvm-bolt main.exe -o main.exe.bolt --update-debug-sections -write-dwp
+; RUN: llvm-dwarfdump --show-form --verbose --debug-types main.exe.bolt.dwp | FileCheck -check-prefix=BOLT %s
+; RUN: llvm-dwarfdump --show-form --verbose --debug-tu-index main.exe.bolt.dwp | FileCheck -check-prefix=BOLT-DWP-TU-INDEX %s
+
+; Test input into bolt a DWP file with TU Index.
+; Make sure the output .dwp file has a type information.
+
+; PRE-BOLT: DW_TAG_type_unit
+; PRE-BOLT: DW_TAG_type_unit
+
+; PRE-BOLT-DWP-TU-INDEX: version = 2, units = 2, slots = 4
+; PRE-BOLT-DWP-TU-INDEX: Index Signature
+; PRE-BOLT-DWP-TU-INDEX: 0x675d23e4f33235f2
+; PRE-BOLT-DWP-TU-INDEX-NEXT: 0x49dc260088be7e56
+
+; BOLT: DW_TAG_type_unit
+; BOLT: DW_TAG_type_unit
+
+; BOLT-DWP-TU-INDEX: version = 2, units = 2, slots = 4
+; BOLT-DWP-TU-INDEX: Index Signature
+; BOLT-DWP-TU-INDEX: 0x675d23e4f33235f2
+; BOLT-DWP-TU-INDEX-NEXT: 0x49dc260088be7e56

bolt/test/X86/dwarf5-ftypes-dwp-input-dwo-output.test

+# REQUIRES: system-linux
+; RUN: rm -rf %t
+; RUN: mkdir %t
+; RUN: cd %t
+; RUN: llvm-mc --split-dwarf-file=main.dwo --triple=x86_64-unknown-linux-gnu \
+; RUN: --filetype=obj %p/Inputs/dwarf5-ftypes-split-dwarf.s -o=main.o
+; RUN: %clang %cflags -gdwarf-5 -gsplit-dwarf=split main.o -o main.exe
+; RUN: llvm-dwp -e main.exe -o main.exe.dwp
+; RUN: llvm-dwarfdump --show-form --verbose --debug-info main.exe.dwp | FileCheck -check-prefix=PRE-BOLT %s
+; RUN: llvm-dwarfdump --show-form --verbose --debug-tu-index main.exe.dwp | FileCheck -check-prefix=PRE-BOLT-DWP-TU-INDEX %s
+; RUN: llvm-bolt main.exe -o main.exe.bolt --update-debug-sections
+; RUN: llvm-dwarfdump --show-form --verbose --debug-info main.dwo.dwo | FileCheck -check-prefix=BOLT %s
+
+; Test input into bolt a DWP file with TU Index.
+; Make sure output in the .dwo files has type information.
+
+; PRE-BOLT: DW_TAG_type_unit
+; PRE-BOLT: DW_TAG_type_unit
+
+; PRE-BOLT-DWP-TU-INDEX: version = 5, units = 2, slots = 4
+; PRE-BOLT-DWP-TU-INDEX: Index Signature
+; PRE-BOLT-DWP-TU-INDEX: 0x675d23e4f33235f2
+; PRE-BOLT-DWP-TU-INDEX-NEXT: 0x49dc260088be7e56
+
+; BOLT: DW_TAG_type_unit
+; BOLT: DW_TAG_type_unit
+; BOLT: DW_TAG_compile_unit

bolt/test/lit.cfg.py

tools = [
     ToolSubst('llvm-nm', unresolved='fatal'),
     ToolSubst('llvm-objdump', unresolved='fatal'),
     ToolSubst('llvm-objcopy', unresolved='fatal'),
     ToolSubst('llvm-strip', unresolved='fatal'),
     ToolSubst('llvm-readelf', unresolved='fatal'),
     ToolSubst('link_fdata', command=link_fdata_cmd, unresolved='fatal'),
     ToolSubst('merge-fdata', unresolved='fatal'),
     ToolSubst('llvm-readobj', unresolved='fatal'),
+    ToolSubst('llvm-dwp', unresolved='fatal'),
 ]
 llvm_config.add_tool_substitutions(tools, tool_dirs)
 
 def calculate_arch_features(arch_string):
     features = []
     for arch in arch_string.split():
         features.append(arch.lower() + '-registered-target')
     return features