Store and emit original name in combined index

[mehdi_amini]

Summary

As discussed in D18298, some local globals can't
be renamed/promoted (because they have a section, or because
they are referenced from inline assembly).
To be able to detect naming collision, we need to keep around
the "GUID" using their original name without taking the linkage
into account.

[mehdi_amini]

rebase

[tejohnson]

lib/Bitcode/Reader/BitcodeReader.cpp

5644

Maybe a comment here and in the below case that for the combined index the original name comes from a separate bitcode record (which is why both are set to the same GUID)?

5896

Don't FS_ALIAS and FS_PERMODULE_GLOBALVAR_INIT_REFS need to setOriginalName as well?

[mehdi_amini]

Address comments, add an alias to the test

[mehdi_amini]

Add a global variable in the test

[tejohnson]

LGTM, except I have one concern about the test, noted below.

test/Bitcode/thinlto-function-summary-originalnames.ll

16

These GUIDs (not the original ones above) might be dangerous to put here as they include the path to the module (which I believe could vary on some bots).

[mehdi_amini]

r267304

test/Bitcode/thinlto-function-summary-originalnames.ll

16

Good point.

[mehdi_amini]

test/Bitcode/thinlto-function-summary-originalnames.ll

16

I added them back, after defining the "source_filename" in the IR.
It turns out that the order of the entries in the GLOBALVAL_SUMMARY_BLOCK are dependent on the path as well, so the test with the -NEXT lines was broken.

include/llvm/Bitcode/LLVMBitCodes.h

enum GlobalValueSummarySymtabCodes {
   //                    n x (valueid, callsitecount, profilecount)]
   FS_COMBINED_PROFILE = 5,
   // COMBINED_GLOBALVAR_INIT_REFS: [modid, linkage, n x valueid]
   FS_COMBINED_GLOBALVAR_INIT_REFS = 6,
   // ALIAS: [valueid, linkage, valueid]
   FS_ALIAS = 7,
   // COMBINED_ALIAS: [modid, linkage, offset]
   FS_COMBINED_ALIAS = 8,
+  // COMBINED_ORIGINAL_NAME: [original_name_hash]
+  FS_COMBINED_ORIGINAL_NAME = 9,
 };
 
 enum MetadataCodes {
   METADATA_STRING_OLD = 1,       // MDSTRING:      [values]
   METADATA_VALUE = 2,            // VALUE:         [type num, value num]
   METADATA_NODE = 3,             // NODE:          [n x md num]
   METADATA_NAME = 4,             // STRING:        [values]
   METADATA_DISTINCT_NODE = 5,    // DISTINCT_NODE: [n x md num]

include/llvm/IR/ModuleSummaryIndex.h

 public:
   /// \brief Sububclass discriminator (for dyn_cast<> et al.)
   enum SummaryKind { AliasKind, FunctionKind, GlobalVarKind };
 
 private:
   /// Kind of summary for use in dyn_cast<> et al.
   SummaryKind Kind;
 
+  /// This is the hash of the name of the symbol in the original file. It is
+  /// identical to the GUID for global symbols, but differs for local since the
+  /// GUID includes the module level id in the hash.
+  GlobalValue::GUID OriginalName;
+
   /// \brief Path of module IR containing value's definition, used to locate
   /// module during importing.
   ///
   /// This is only used during parsing of the combined index, or when
   /// parsing the per-module index for creation of the combined summary index,
   /// not during writing of the per-module index which doesn't contain a
   /// module path string table.
   StringRef ModulePath;

 protected:
   /// GlobalValueSummary constructor.
   GlobalValueSummary(SummaryKind K, GlobalValue::LinkageTypes Linkage)
       : Kind(K), Linkage(Linkage) {}
 
 public:
   virtual ~GlobalValueSummary() = default;
 
+  /// Returns the hash of the original name, it is identical to the GUID for
+  /// externally visible symbols, but not for local ones.
+  GlobalValue::GUID getOriginalName() { return OriginalName; }
+
+  /// Initialize the original name hash in this summary.
+  void setOriginalName(GlobalValue::GUID Name) { OriginalName = Name; }
+
   /// Which kind of summary subclass this is.
   SummaryKind getSummaryKind() const { return Kind; }
 
   /// Set the path to the module containing this function, for use in
   /// the combined index.
   void setModulePath(StringRef ModPath) { ModulePath = ModPath; }
 
   /// Get the path to the module containing this function.

lib/Bitcode/Reader/BitcodeReader.cpp

class ModuleSummaryIndexBitcodeReader {
   /// Used to enable on-demand parsing of the VST.
   uint64_t VSTOffset = 0;
 
   // Map to save ValueId to GUID association that was recorded in the
   // ValueSymbolTable. It is used after the VST is parsed to convert
   // call graph edges read from the function summary from referencing
   // callees by their ValueId to using the GUID instead, which is how
   // they are recorded in the summary index being built.
-  DenseMap<unsigned, GlobalValue::GUID> ValueIdToCallGraphGUIDMap;
+  // We save a second GUID which is the same as the first one, but ignoring the
+  // linkage, i.e. for value other than local linkage they are identical.
+  DenseMap<unsigned, std::pair<GlobalValue::GUID, GlobalValue::GUID>>
+      ValueIdToCallGraphGUIDMap;
 
   /// Map to save the association between summary offset in the VST to the
   /// GlobalValueInfo object created when parsing it. Used to access the
   /// info object when parsing the summary section.
   DenseMap<uint64_t, GlobalValueInfo *> SummaryOffsetToInfoMap;
 
   /// Map populated during module path string table parsing, from the
   /// module ID to a string reference owned by the index's module
private:
   std::error_code parseValueSymbolTable(
       uint64_t Offset,
       DenseMap<unsigned, GlobalValue::LinkageTypes> &ValueIdToLinkageMap);
   std::error_code parseEntireSummary();
   std::error_code parseModuleStringTable();
   std::error_code initStream(std::unique_ptr<DataStreamer> Streamer);
   std::error_code initStreamFromBuffer();
   std::error_code initLazyStream(std::unique_ptr<DataStreamer> Streamer);
-  GlobalValue::GUID getGUIDFromValueId(unsigned ValueId);
+  std::pair<GlobalValue::GUID, GlobalValue::GUID>
+  getGUIDFromValueId(unsigned ValueId);
   GlobalValueInfo *getInfoFromSummaryOffset(uint64_t Offset);
 };
 } // end anonymous namespace
 
 BitcodeDiagnosticInfo::BitcodeDiagnosticInfo(std::error_code EC,
                                              DiagnosticSeverity Severity,
                                              const Twine &Msg)
     : DiagnosticInfo(DK_Bitcode, Severity), Msg(Msg), EC(EC) {}
ModuleSummaryIndexBitcodeReader::ModuleSummaryIndexBitcodeReader(
     bool CheckGlobalValSummaryPresenceOnly)
     : DiagnosticHandler(DiagnosticHandler), Buffer(nullptr),
       CheckGlobalValSummaryPresenceOnly(CheckGlobalValSummaryPresenceOnly) {}
 
 void ModuleSummaryIndexBitcodeReader::freeState() { Buffer = nullptr; }
 
 void ModuleSummaryIndexBitcodeReader::releaseBuffer() { Buffer.release(); }
 
-GlobalValue::GUID
+std::pair<GlobalValue::GUID, GlobalValue::GUID>
 ModuleSummaryIndexBitcodeReader::getGUIDFromValueId(unsigned ValueId) {
   auto VGI = ValueIdToCallGraphGUIDMap.find(ValueId);
   assert(VGI != ValueIdToCallGraphGUIDMap.end());
   return VGI->second;
 }
 
 GlobalValueInfo *
 ModuleSummaryIndexBitcodeReader::getInfoFromSummaryOffset(uint64_t Offset) {
case bitc::VST_CODE_ENTRY: { // VST_CODE_ENTRY: [valueid, namechar x N]
         return error("Invalid record");
       unsigned ValueID = Record[0];
       std::unique_ptr<GlobalValueInfo> GlobalValInfo =
           llvm::make_unique<GlobalValueInfo>();
       assert(!SourceFileName.empty());
       auto VLI = ValueIdToLinkageMap.find(ValueID);
       assert(VLI != ValueIdToLinkageMap.end() &&
              "No linkage found for VST entry?");
-      std::string GlobalId = GlobalValue::getGlobalIdentifier(
-          ValueName, VLI->second, SourceFileName);
+      auto Linkage = VLI->second;
+      std::string GlobalId =
+          GlobalValue::getGlobalIdentifier(ValueName, Linkage, SourceFileName);
       auto ValueGUID = GlobalValue::getGUID(GlobalId);
+      auto OriginalNameID = ValueGUID;
+      if (GlobalValue::isLocalLinkage(Linkage))
+        OriginalNameID = GlobalValue::getGUID(ValueName);
       if (PrintSummaryGUIDs)
-        dbgs() << "GUID " << ValueGUID << " is " << ValueName << "\n";
+        dbgs() << "GUID " << ValueGUID << "(" << OriginalNameID << ") is "
+               << ValueName << "\n";
       TheIndex->addGlobalValueInfo(ValueGUID, std::move(GlobalValInfo));
-      ValueIdToCallGraphGUIDMap[ValueID] = ValueGUID;
+      ValueIdToCallGraphGUIDMap[ValueID] =
+          std::make_pair(ValueGUID, OriginalNameID);
       ValueName.clear();
       break;
     }
     case bitc::VST_CODE_FNENTRY: {
       // VST_CODE_FNENTRY: [valueid, offset, namechar x N]
       if (convertToString(Record, 2, ValueName))
         return error("Invalid record");
       unsigned ValueID = Record[0];
       uint64_t FuncOffset = Record[1];
       std::unique_ptr<GlobalValueInfo> FuncInfo =
           llvm::make_unique<GlobalValueInfo>(FuncOffset);
       assert(!SourceFileName.empty());
       auto VLI = ValueIdToLinkageMap.find(ValueID);
       assert(VLI != ValueIdToLinkageMap.end() &&
              "No linkage found for VST entry?");
+      auto Linkage = VLI->second;
       std::string FunctionGlobalId = GlobalValue::getGlobalIdentifier(
           ValueName, VLI->second, SourceFileName);
       auto FunctionGUID = GlobalValue::getGUID(FunctionGlobalId);
+      auto OriginalNameID = FunctionGUID;
+      if (GlobalValue::isLocalLinkage(Linkage))
+        OriginalNameID = GlobalValue::getGUID(ValueName);
       if (PrintSummaryGUIDs)
-        dbgs() << "GUID " << FunctionGUID << " is " << ValueName << "\n";
+        dbgs() << "GUID " << FunctionGUID << "(" << OriginalNameID << ") is "
+               << ValueName << "\n";
       TheIndex->addGlobalValueInfo(FunctionGUID, std::move(FuncInfo));
-      ValueIdToCallGraphGUIDMap[ValueID] = FunctionGUID;
+      ValueIdToCallGraphGUIDMap[ValueID] =
+          std::make_pair(FunctionGUID, OriginalNameID);
 
       ValueName.clear();
       break;
     }
     case bitc::VST_CODE_COMBINED_GVDEFENTRY: {
       // VST_CODE_COMBINED_GVDEFENTRY: [valueid, offset, guid]
       unsigned ValueID = Record[0];
       uint64_t GlobalValSummaryOffset = Record[1];
       GlobalValue::GUID GlobalValGUID = Record[2];
       std::unique_ptr<GlobalValueInfo> GlobalValInfo =
           llvm::make_unique<GlobalValueInfo>(GlobalValSummaryOffset);
       SummaryOffsetToInfoMap[GlobalValSummaryOffset] = GlobalValInfo.get();
       TheIndex->addGlobalValueInfo(GlobalValGUID, std::move(GlobalValInfo));
-      ValueIdToCallGraphGUIDMap[ValueID] = GlobalValGUID;
+      ValueIdToCallGraphGUIDMap[ValueID] =
+          std::make_pair(GlobalValGUID, GlobalValGUID);
       break;
     }
     case bitc::VST_CODE_COMBINED_ENTRY: {
       // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
       unsigned ValueID = Record[0];
       GlobalValue::GUID RefGUID = Record[1];
-      ValueIdToCallGraphGUIDMap[ValueID] = RefGUID;
+      ValueIdToCallGraphGUIDMap[ValueID] = std::make_pair(RefGUID, RefGUID);
       break;
     }
     }
   }
 }
 
 // Parse just the blocks needed for building the index out of the module.
 // At the end of this routine the module Index is populated with a map

 
 // Eagerly parse the entire summary block. This populates the GlobalValueSummary
 // objects in the index.
 std::error_code ModuleSummaryIndexBitcodeReader::parseEntireSummary() {
   if (Stream.EnterSubBlock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID))
     return error("Invalid record");
 
   SmallVector<uint64_t, 64> Record;
-
+  // Keep around the last seen summary to be used when we see an optional
+  // "OriginalName" attachement.
+  GlobalValueSummary *LastSeenSummary = nullptr;
   bool Combined = false;
   while (1) {
     BitstreamEntry Entry = Stream.advanceSkippingSubblocks();
 
     switch (Entry.Kind) {
     case BitstreamEntry::SubBlock: // Handled for us already.
     case BitstreamEntry::Error:
       return error("Malformed block");
case bitc::FS_PERMODULE_PROFILE: {
       FS->setModulePath(
           TheIndex->addModulePath(Buffer->getBufferIdentifier(), 0)->first());
       static int RefListStartIndex = 4;
       int CallGraphEdgeStartIndex = RefListStartIndex + NumRefs;
       assert(Record.size() >= RefListStartIndex + NumRefs &&
              "Record size inconsistent with number of references");
       for (unsigned I = 4, E = CallGraphEdgeStartIndex; I != E; ++I) {
         unsigned RefValueId = Record[I];
-        GlobalValue::GUID RefGUID = getGUIDFromValueId(RefValueId);
+        GlobalValue::GUID RefGUID = getGUIDFromValueId(RefValueId).first;
         FS->addRefEdge(RefGUID);
       }
       bool HasProfile = (BitCode == bitc::FS_PERMODULE_PROFILE);
       for (unsigned I = CallGraphEdgeStartIndex, E = Record.size(); I != E;
            ++I) {
         unsigned CalleeValueId = Record[I];
         unsigned CallsiteCount = Record[++I];
         uint64_t ProfileCount = HasProfile ? Record[++I] : 0;
-        GlobalValue::GUID CalleeGUID = getGUIDFromValueId(CalleeValueId);
+        GlobalValue::GUID CalleeGUID = getGUIDFromValueId(CalleeValueId).first;
         FS->addCallGraphEdge(CalleeGUID,
                              CalleeInfo(CallsiteCount, ProfileCount));
       }
-      GlobalValue::GUID GUID = getGUIDFromValueId(ValueID);
-      auto *Info = TheIndex->getGlobalValueInfo(GUID);
+      auto GUID = getGUIDFromValueId(ValueID);
+      FS->setOriginalName(GUID.second);
+      auto *Info = TheIndex->getGlobalValueInfo(GUID.first);
       assert(!Info->summary() && "Expected a single summary per VST entry");
       Info->setSummary(std::move(FS));
       break;
     }
     // FS_ALIAS: [valueid, linkage, valueid]
     // Aliases must be emitted (and parsed) after all FS_PERMODULE entries, as
     // they expect all aliasee summaries to be available.
     case bitc::FS_ALIAS: {
       unsigned ValueID = Record[0];
       uint64_t RawLinkage = Record[1];
       unsigned AliaseeID = Record[2];
       std::unique_ptr<AliasSummary> AS =
           llvm::make_unique<AliasSummary>(getDecodedLinkage(RawLinkage));
       // The module path string ref set in the summary must be owned by the
       // index's module string table. Since we don't have a module path
       // string table section in the per-module index, we create a single
       // module path string table entry with an empty (0) ID to take
       // ownership.
       AS->setModulePath(
           TheIndex->addModulePath(Buffer->getBufferIdentifier(), 0)->first());
 
-      GlobalValue::GUID AliaseeGUID = getGUIDFromValueId(AliaseeID);
+      GlobalValue::GUID AliaseeGUID = getGUIDFromValueId(AliaseeID).first;
       auto *AliaseeInfo = TheIndex->getGlobalValueInfo(AliaseeGUID);
       if (!AliaseeInfo->summary())
         return error("Alias expects aliasee summary to be parsed");
       AS->setAliasee(AliaseeInfo->summary());
 
-      GlobalValue::GUID GUID = getGUIDFromValueId(ValueID);
+      GlobalValue::GUID GUID = getGUIDFromValueId(ValueID).first;
       auto *Info = TheIndex->getGlobalValueInfo(GUID);
       assert(!Info->summary() && "Expected a single summary per VST entry");
       Info->setSummary(std::move(AS));
       break;
     }
     // FS_PERMODULE_GLOBALVAR_INIT_REFS: [valueid, linkage, n x valueid]
     case bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS: {
       unsigned ValueID = Record[0];
       uint64_t RawLinkage = Record[1];
       std::unique_ptr<GlobalVarSummary> FS =
           llvm::make_unique<GlobalVarSummary>(getDecodedLinkage(RawLinkage));
       FS->setModulePath(
           TheIndex->addModulePath(Buffer->getBufferIdentifier(), 0)->first());
       for (unsigned I = 2, E = Record.size(); I != E; ++I) {
         unsigned RefValueId = Record[I];
-        GlobalValue::GUID RefGUID = getGUIDFromValueId(RefValueId);
+        GlobalValue::GUID RefGUID = getGUIDFromValueId(RefValueId).first;
         FS->addRefEdge(RefGUID);
       }
-      GlobalValue::GUID GUID = getGUIDFromValueId(ValueID);
+      GlobalValue::GUID GUID = getGUIDFromValueId(ValueID).first;
       auto *Info = TheIndex->getGlobalValueInfo(GUID);
       assert(!Info->summary() && "Expected a single summary per VST entry");
       Info->setSummary(std::move(FS));
       break;
     }
     // FS_COMBINED: [modid, linkage, instcount, numrefs, numrefs x valueid,
     //               n x (valueid, callsitecount)]
     // FS_COMBINED_PROFILE: [modid, linkage, instcount, numrefs,
     //                       numrefs x valueid,
     //                       n x (valueid, callsitecount, profilecount)]
     case bitc::FS_COMBINED:
     case bitc::FS_COMBINED_PROFILE: {
       uint64_t ModuleId = Record[0];
       uint64_t RawLinkage = Record[1];
       unsigned InstCount = Record[2];
       unsigned NumRefs = Record[3];
       std::unique_ptr<FunctionSummary> FS = llvm::make_unique<FunctionSummary>(
           getDecodedLinkage(RawLinkage), InstCount);
+      LastSeenSummary = FS.get();
       FS->setModulePath(ModuleIdMap[ModuleId]);
       static int RefListStartIndex = 4;
       int CallGraphEdgeStartIndex = RefListStartIndex + NumRefs;
       assert(Record.size() >= RefListStartIndex + NumRefs &&
              "Record size inconsistent with number of references");
       for (unsigned I = 4, E = CallGraphEdgeStartIndex; I != E; ++I) {
         unsigned RefValueId = Record[I];
-        GlobalValue::GUID RefGUID = getGUIDFromValueId(RefValueId);
+        GlobalValue::GUID RefGUID = getGUIDFromValueId(RefValueId).first;
         FS->addRefEdge(RefGUID);
       }
       bool HasProfile = (BitCode == bitc::FS_COMBINED_PROFILE);
       for (unsigned I = CallGraphEdgeStartIndex, E = Record.size(); I != E;
            ++I) {
         unsigned CalleeValueId = Record[I];
         unsigned CallsiteCount = Record[++I];
         uint64_t ProfileCount = HasProfile ? Record[++I] : 0;
-        GlobalValue::GUID CalleeGUID = getGUIDFromValueId(CalleeValueId);
+        GlobalValue::GUID CalleeGUID = getGUIDFromValueId(CalleeValueId).first;
         FS->addCallGraphEdge(CalleeGUID,
                              CalleeInfo(CallsiteCount, ProfileCount));
       }
       auto *Info = getInfoFromSummaryOffset(CurRecordBit);
       assert(!Info->summary() && "Expected a single summary per VST entry");
       Info->setSummary(std::move(FS));
       Combined = true;
       break;
     }
     // FS_COMBINED_ALIAS: [modid, linkage, offset]
     // Aliases must be emitted (and parsed) after all FS_COMBINED entries, as
     // they expect all aliasee summaries to be available.
     case bitc::FS_COMBINED_ALIAS: {
       uint64_t ModuleId = Record[0];
       uint64_t RawLinkage = Record[1];
       uint64_t AliaseeSummaryOffset = Record[2];
       std::unique_ptr<AliasSummary> AS =
           llvm::make_unique<AliasSummary>(getDecodedLinkage(RawLinkage));
+      LastSeenSummary = AS.get();
       AS->setModulePath(ModuleIdMap[ModuleId]);
 
       auto *AliaseeInfo = getInfoFromSummaryOffset(AliaseeSummaryOffset);
       if (!AliaseeInfo->summary())
         return error("Alias expects aliasee summary to be parsed");
       AS->setAliasee(AliaseeInfo->summary());
 
       auto *Info = getInfoFromSummaryOffset(CurRecordBit);
       assert(!Info->summary() && "Expected a single summary per VST entry");
       Info->setSummary(std::move(AS));
       Combined = true;
       break;
     }
     // FS_COMBINED_GLOBALVAR_INIT_REFS: [modid, linkage, n x valueid]
     case bitc::FS_COMBINED_GLOBALVAR_INIT_REFS: {
       uint64_t ModuleId = Record[0];
       uint64_t RawLinkage = Record[1];
       std::unique_ptr<GlobalVarSummary> FS =
           llvm::make_unique<GlobalVarSummary>(getDecodedLinkage(RawLinkage));
+      LastSeenSummary = FS.get();
       FS->setModulePath(ModuleIdMap[ModuleId]);
       for (unsigned I = 2, E = Record.size(); I != E; ++I) {
         unsigned RefValueId = Record[I];
-        GlobalValue::GUID RefGUID = getGUIDFromValueId(RefValueId);
+        GlobalValue::GUID RefGUID = getGUIDFromValueId(RefValueId).first;
         FS->addRefEdge(RefGUID);
       }
       auto *Info = getInfoFromSummaryOffset(CurRecordBit);
       assert(!Info->summary() && "Expected a single summary per VST entry");
       Info->setSummary(std::move(FS));
       Combined = true;
       break;
     }
+    // FS_COMBINED_ORIGINAL_NAME: [original_name]
+    case bitc::FS_COMBINED_ORIGINAL_NAME: {
+      uint64_t OriginalName = Record[0];
+      if (!LastSeenSummary)
+        return error("Name attachment that does not follow a combined record");
+      LastSeenSummary->setOriginalName(OriginalName);
+      // Reset the LastSeenSummary
+      LastSeenSummary = nullptr;
+    }
     }
   }
   llvm_unreachable("Exit infinite loop");
 }
 
 // Parse the  module string table block into the Index.
 // This populates the ModulePathStringTable map in the index.
 std::error_code ModuleSummaryIndexBitcodeReader::parseModuleStringTable() {

lib/Bitcode/Writer/BitcodeWriter.cpp

void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
 
   // The aliases are emitted as a post-pass, and will point to the summary
   // offset id of the aliasee. For this purpose we need to be able to get back
   // from the summary to the offset
   SmallVector<GlobalValueInfo *, 64> Aliases;
   DenseMap<const GlobalValueSummary *, uint64_t> SummaryToOffsetMap;
 
   SmallVector<uint64_t, 64> NameVals;
+
+  // For local linkage, we also emit the original name separately
+  // immediately after the record.
+  auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
+    if (GlobalValue::isLocalLinkage(S.linkage())) {
+      NameVals.push_back(S.getOriginalName());
+      stream().EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
+      NameVals.clear();
+    }
+  };
+
   for (const auto &FII : *Index) {
     for (auto &FI : FII.second) {
       GlobalValueSummary *S = FI->summary();
       assert(S);
       if (isa<AliasSummary>(S)) {
         // Will process aliases as a post-pass because the reader wants all
         // global to be loaded first.
         Aliases.push_back(FI.get());
for (auto &FI : FII.second) {
                             stream().GetAbbrevIDWidth());
         // Store temporarily the offset in the map for a possible alias.
         SummaryToOffsetMap[S] = FI->bitcodeIndex();
 
         // Emit the finished record.
         stream().EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
                             FSModRefsAbbrev);
         NameVals.clear();
+        MaybeEmitOriginalName(*S);
         continue;
       }
 
       auto *FS = cast<FunctionSummary>(S);
       NameVals.push_back(Index->getModuleId(FS->modulePath()));
       NameVals.push_back(getEncodedLinkage(FS->linkage()));
       NameVals.push_back(FS->instCount());
       NameVals.push_back(FS->refs().size());
for (auto &FI : FII.second) {
       unsigned FSAbbrev =
           (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
       unsigned Code =
           (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
 
       // Emit the finished record.
       stream().EmitRecord(Code, NameVals, FSAbbrev);
       NameVals.clear();
+      MaybeEmitOriginalName(*S);
     }
   }
 
   for (auto GVI : Aliases) {
     AliasSummary *AS = cast<AliasSummary>(GVI->summary());
     NameVals.push_back(Index->getModuleId(AS->modulePath()));
     NameVals.push_back(getEncodedLinkage(AS->linkage()));
     auto AliaseeOffset = SummaryToOffsetMap[&AS->getAliasee()];
     assert(AliaseeOffset);
     NameVals.push_back(AliaseeOffset);
 
     // Record the starting offset of this summary entry for use
     // in the VST entry. Add the current code size since the
     // reader will invoke readRecord after the abbrev id read.
     GVI->setBitcodeIndex(stream().GetCurrentBitNo() +
                          stream().GetAbbrevIDWidth());
 
     // Emit the finished record.
     stream().EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
     NameVals.clear();
+    MaybeEmitOriginalName(*AS);
   }
 
   stream().ExitBlock();
 }
 
 void ModuleBitcodeWriter::writeIdentificationBlock() {
   stream().EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
 

test/Bitcode/thinlto-function-summary-originalnames.ll

+; Test to check the callgraph in summary
+; RUN: opt -module-summary %s -o %t.o
+; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t.o
+; RUN: llvm-bcanalyzer -dump %t.index.bc | FileCheck %s --check-prefix=COMBINED
+
+; COMBINED:       <GLOBALVAL_SUMMARY_BLOCK
+; COMBINED-NEXT:    <COMBINED
+; COMBINED-NEXT:    <COMBINED_ORIGINAL_NAME op0=6699318081062747564/>
+; COMBINED-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
+; COMBINED-NEXT:  <VALUE_SYMTAB
+; COMBINED-NEXT:    <COMBINED_GVDEFENTRY {{.*}} op2=-8709959634447057722/>
+; COMBINED-NEXT:  </VALUE_SYMTAB>
+
+; ModuleID = 'thinlto-function-summary-callgraph.ll'
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @foo() {
+    ret void
+}
 No newline at end of file

tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp

default:
       STRINGIFY_CODE(FS, PERMODULE)
       STRINGIFY_CODE(FS, PERMODULE_PROFILE)
       STRINGIFY_CODE(FS, PERMODULE_GLOBALVAR_INIT_REFS)
       STRINGIFY_CODE(FS, COMBINED)
       STRINGIFY_CODE(FS, COMBINED_PROFILE)
       STRINGIFY_CODE(FS, COMBINED_GLOBALVAR_INIT_REFS)
       STRINGIFY_CODE(FS, ALIAS)
       STRINGIFY_CODE(FS, COMBINED_ALIAS)
+      STRINGIFY_CODE(FS, COMBINED_ORIGINAL_NAME)
     }
   case bitc::METADATA_ATTACHMENT_ID:
     switch(CodeID) {
     default:return nullptr;
       STRINGIFY_CODE(METADATA, ATTACHMENT)
     }
   case bitc::METADATA_BLOCK_ID:
     switch(CodeID) {