[Assembler] Emit summary index flags

Differential revision: https://reviews.llvm.org/D74420

llvm/include/llvm/IR/ModuleSummaryIndex.h

@@ -1037,6 +1037,9 @@ public:
 
   bool haveGVs() const { return HaveGVs; }
 
+  uint64_t getFlags() const;
+  void setFlags(uint64_t Flags);
+
   gvsummary_iterator begin() { return GlobalValueMap.begin(); }
   const_gvsummary_iterator begin() const { return GlobalValueMap.begin(); }
   gvsummary_iterator end() { return GlobalValueMap.end(); }

llvm/lib/AsmParser/LLParser.cpp

@@ -835,6 +835,9 @@ bool LLParser::ParseSummaryEntry() {
   case lltok::kw_typeidCompatibleVTable:
     result = ParseTypeIdCompatibleVtableEntry(SummaryID);
     break;
+  case lltok::kw_flags:
+    result = ParseSummaryIndexFlags();
+    break;
   default:
     result = Error(Lex.getLoc(), "unexpected summary kind");
     break;
@@ -7995,6 +7998,21 @@ void LLParser::AddGlobalValueToIndex(
   }
 }
 
+/// ParseSummaryIndexFlags
+///   ::= 'flags' ':' UInt64
+bool LLParser::ParseSummaryIndexFlags() {
+  assert(Lex.getKind() == lltok::kw_flags);
+  Lex.Lex();
+
+  if (ParseToken(lltok::colon, "expected ':' here"))
+    return true;
+  uint64_t Flags;
+  if (ParseUInt64(Flags))
+    return true;
+  Index->setFlags(Flags);
+  return false;
+}
+
 /// ParseGVEntry
 ///   ::= 'gv' ':' '(' ('name' ':' STRINGCONSTANT | 'guid' ':' UInt64)
 ///         [',' 'summaries' ':' Summary[',' Summary]* ]? ')'

llvm/lib/AsmParser/LLParser.h

@@ -347,6 +347,7 @@ namespace llvm {
     bool ParseModuleEntry(unsigned ID);
     bool ParseModuleReference(StringRef &ModulePath);
     bool ParseGVReference(ValueInfo &VI, unsigned &GVId);
+    bool ParseSummaryIndexFlags();
     bool ParseGVEntry(unsigned ID);
     bool ParseFunctionSummary(std::string Name, GlobalValue::GUID, unsigned ID);
     bool ParseVariableSummary(std::string Name, GlobalValue::GUID, unsigned ID);

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -5836,35 +5836,7 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
     default: // Default behavior: ignore.
       break;
     case bitc::FS_FLAGS: {  // [flags]
-      uint64_t Flags = Record[0];
-      // Scan flags.
-      assert(Flags <= 0x3f && "Unexpected bits in flag");
-
-      // 1 bit: WithGlobalValueDeadStripping flag.
-      // Set on combined index only.
-      if (Flags & 0x1)
-        TheIndex.setWithGlobalValueDeadStripping();
-      // 1 bit: SkipModuleByDistributedBackend flag.
-      // Set on combined index only.
-      if (Flags & 0x2)
-        TheIndex.setSkipModuleByDistributedBackend();
-      // 1 bit: HasSyntheticEntryCounts flag.
-      // Set on combined index only.
-      if (Flags & 0x4)
-        TheIndex.setHasSyntheticEntryCounts();
-      // 1 bit: DisableSplitLTOUnit flag.
-      // Set on per module indexes. It is up to the client to validate
-      // the consistency of this flag across modules being linked.
-      if (Flags & 0x8)
-        TheIndex.setEnableSplitLTOUnit();
-      // 1 bit: PartiallySplitLTOUnits flag.
-      // Set on combined index only.
-      if (Flags & 0x10)
-        TheIndex.setPartiallySplitLTOUnits();
-      // 1 bit: WithAttributePropagation flag.
-      // Set on combined index only.
-      if (Flags & 0x20)
-        TheIndex.setWithAttributePropagation();
+      TheIndex.setFlags(Record[0]);
       break;
     }
     case bitc::FS_VALUE_GUID: { // [valueid, refguid]

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -3898,20 +3898,7 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
 
   // Write the index flags.
-  uint64_t Flags = 0;
-  if (Index.withGlobalValueDeadStripping())
-    Flags |= 0x1;
-  if (Index.skipModuleByDistributedBackend())
-    Flags |= 0x2;
-  if (Index.hasSyntheticEntryCounts())
-    Flags |= 0x4;
-  if (Index.enableSplitLTOUnit())
-    Flags |= 0x8;
-  if (Index.partiallySplitLTOUnits())
-    Flags |= 0x10;
-  if (Index.withAttributePropagation())
-    Flags |= 0x20;
-  Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
+  Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
 
   for (const auto &GVI : valueIds()) {
     Stream.EmitRecord(bitc::FS_VALUE_GUID,

llvm/lib/IR/AsmWriter.cpp

@@ -783,7 +783,7 @@ public:
 
   /// These functions do the actual initialization.
   inline void initializeIfNeeded();
-  void initializeIndexIfNeeded();
+  int initializeIndexIfNeeded();
 
   // Implementation Details
 private:
@@ -806,7 +806,8 @@ private:
   /// Add all of the module level global variables (and their initializers)
   /// and function declarations, but not the contents of those functions.
   void processModule();
-  void processIndex();
+  // Returns number of allocated slots
+  int processIndex();
 
   /// Add all of the functions arguments, basic blocks, and instructions.
   void processFunction();
@@ -920,11 +921,12 @@ inline void SlotTracker::initializeIfNeeded() {
     processFunction();
 }
 
-void SlotTracker::initializeIndexIfNeeded() {
+int SlotTracker::initializeIndexIfNeeded() {
   if (!TheIndex)
-    return;
-  processIndex();
+    return 0;
+  int NumSlots = processIndex();
   TheIndex = nullptr; ///< Prevent re-processing next time we're called.
+  return NumSlots;
 }
 
 // Iterate through all the global variables, functions, and global
@@ -1019,7 +1021,7 @@ void SlotTracker::processFunction() {
 }
 
 // Iterate through all the GUID in the index and create slots for them.
-void SlotTracker::processIndex() {
+int SlotTracker::processIndex() {
   ST_DEBUG("begin processIndex!\n");
   assert(TheIndex);
 
@@ -1038,17 +1040,17 @@ void SlotTracker::processIndex() {
   for (auto &GlobalList : *TheIndex)
     CreateGUIDSlot(GlobalList.first);
 
+  for (auto &TId : TheIndex->typeIdCompatibleVtableMap())
+    CreateGUIDSlot(GlobalValue::getGUID(TId.first));
+
   // Start numbering the TypeIds after the GUIDs.
   TypeIdNext = GUIDNext;
-
   for (auto TidIter = TheIndex->typeIds().begin();
        TidIter != TheIndex->typeIds().end(); TidIter++)
     CreateTypeIdSlot(TidIter->second.first);
 
-  for (auto &TId : TheIndex->typeIdCompatibleVtableMap())
-    CreateGUIDSlot(GlobalValue::getGUID(TId.first));
-
   ST_DEBUG("end processIndex!\n");
+  return TypeIdNext;
 }
 
 void SlotTracker::processGlobalObjectMetadata(const GlobalObject &GO) {
@@ -2678,7 +2680,7 @@ void AssemblyWriter::printModule(const Module *M) {
 
 void AssemblyWriter::printModuleSummaryIndex() {
   assert(TheIndex);
-  Machine.initializeIndexIfNeeded();
+  int NumSlots = Machine.initializeIndexIfNeeded();
 
   Out << "\n";
 
@@ -2740,6 +2742,10 @@ void AssemblyWriter::printModuleSummaryIndex() {
     printTypeIdCompatibleVtableSummary(TId.second);
     Out << ") ; guid = " << GUID << "\n";
   }
+
+  // Don't emit flags when it's not really needed (value is zero by default).
+  if (TheIndex->getFlags())
+    Out << "^" << NumSlots << " = flags: " << TheIndex->getFlags() << "\n";
 }
 
 static const char *

llvm/lib/IR/ModuleSummaryIndex.cpp

@@ -72,6 +72,52 @@ std::pair<unsigned, unsigned> FunctionSummary::specialRefCounts() const {
 
 constexpr uint64_t ModuleSummaryIndex::BitcodeSummaryVersion;
 
+uint64_t ModuleSummaryIndex::getFlags() const {
+  uint64_t Flags = 0;
+  if (withGlobalValueDeadStripping())
+    Flags |= 0x1;
+  if (skipModuleByDistributedBackend())
+    Flags |= 0x2;
+  if (hasSyntheticEntryCounts())
+    Flags |= 0x4;
+  if (enableSplitLTOUnit())
+    Flags |= 0x8;
+  if (partiallySplitLTOUnits())
+    Flags |= 0x10;
+  if (withAttributePropagation())
+    Flags |= 0x20;
+  return Flags;
+}
+
+void ModuleSummaryIndex::setFlags(uint64_t Flags) {
+  assert(Flags <= 0x3f && "Unexpected bits in flag");
+  // 1 bit: WithGlobalValueDeadStripping flag.
+  // Set on combined index only.
+  if (Flags & 0x1)
+    setWithGlobalValueDeadStripping();
+  // 1 bit: SkipModuleByDistributedBackend flag.
+  // Set on combined index only.
+  if (Flags & 0x2)
+    setSkipModuleByDistributedBackend();
+  // 1 bit: HasSyntheticEntryCounts flag.
+  // Set on combined index only.
+  if (Flags & 0x4)
+    setHasSyntheticEntryCounts();
+  // 1 bit: DisableSplitLTOUnit flag.
+  // Set on per module indexes. It is up to the client to validate
+  // the consistency of this flag across modules being linked.
+  if (Flags & 0x8)
+    setEnableSplitLTOUnit();
+  // 1 bit: PartiallySplitLTOUnits flag.
+  // Set on combined index only.
+  if (Flags & 0x10)
+    setPartiallySplitLTOUnits();
+  // 1 bit: WithAttributePropagation flag.
+  // Set on combined index only.
+  if (Flags & 0x20)
+    setWithAttributePropagation();
+}
+
 // Collect for the given module the list of function it defines
 // (GUID -> Summary).
 void ModuleSummaryIndex::collectDefinedFunctionsForModule(

llvm/test/Assembler/summary-flags.ll

@@ -0,0 +1,12 @@
+; ModuleID = 'tmp.bc'
+source_filename = "tmp.bc"
+
+; Test parsing of summary flas. Expect that flags value is the same after round-trip through
+; RUN: llvm-as %s -o - | llvm-dis -o - | FileCheck %s
+; CHECK:       ^0 = module
+; CHECK-NEXT:  ^1 = gv
+; CHECK-NEXT:  ^2 = flags: 33
+
+^0 = module: (path: "main.bc", hash: (3499594384, 1671013073, 3271036935, 1830411232, 59290952))
+^1 = gv: (guid: 15822663052811949562, summaries: (function: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 1, dsoLocal: 1, canAutoHide: 0), insts: 2)))
+^2 = flags: 33