IR: Function summary extensions for whole-program devirtualization pass.

[pcc]

Summary

The summary information includes all uses of llvm.type.test and
llvm.type.checked.load intrinsics that can be used to devirtualize calls,
including any constant arguments for virtual constant propagation.

[tejohnson]

llvm/include/llvm/IR/ModuleSummaryIndex.h

256

I wonder if GUID should be moved out of GlobalValue since we are now using it for types?

260

Maybe "all constant integer args" to be clearer?

282

Maybe "do not have all constant integer arguments" to be clearer?

llvm/lib/Analysis/ModuleSummaryAnalysis.cpp

91

Why arg_begin() + 1? Skipping the "this" pointer? Maybe add a comment.

163

This handling is getting long - consider outlining

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

3371

Why no abbrev ids for these record types?

3371

Add comments to new static funcs here and elsewhere

[pcc]

• Address review comments

llvm/include/llvm/IR/ModuleSummaryIndex.h

256

Not sure -- it isn't clear where else it should go though. One possibility is ModuleSummaryIndex, but that will also require moving getGUID to avoid a circular dependency. Moving it should probably be a separate cleanup, I reckon.

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

3371

Why no abbrev ids for these record types?

It isn't clear that it would be worth it with the current abbrev scheme. VBR would be a good choice for offsets and arguments since they are typically relatively small, but GUIDs are evenly distributed so the best choice for those would be Fixed.

So a good abbrev for *_VCALLS would involve an array of (Fixed, VBR) pairs, but I don't think we can express that at the moment. And a good abbrev for *_CONST_VCALL would use an array of VBR. But that is basically just the encoding we use at the moment for unabbreviated records.

[tejohnson]

llvm/include/llvm/Bitcode/LLVMBitCodes.h

221

Add the "all constant" to comments for records too.

llvm/include/llvm/IR/ModuleSummaryIndex.h

256

I'm not sure either, and it doesn't have to be done in this patch, but it stood out to me since we are adding more non-GV uses of this functionality. The summary is not the right place, since getGUID and GUID are also used in the instrumentation based PGO functionality.

[mehdi_amini]

llvm/trunk/include/llvm/IR/ModuleSummaryIndex.h

253 ↗

(On Diff #88056)

address point?

Beyond the typo, I have no idea reading this what is the address pointer referring to? Is it the address of the vtable?

266 ↗

(On Diff #88056)

The plan being to decorate edges in general with constant arguments, there is potential for code-sharing here.

288 ↗

(On Diff #88056)

How much do we grow the size of index entries? It seems that we're adding 5 vectors while in the general case this feature is unused.
Can we get an auxiliary structure of some sort?

355 ↗

(On Diff #88056)

inline is the default here, isn't it?

llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp

4854 ↗

(On Diff #88056)

Document.

[pcc]

llvm/trunk/include/llvm/IR/ModuleSummaryIndex.h

253 ↗

(On Diff #88056)

"address point" is as defined here: https://mentorembedded.github.io/cxx-abi/abi.html#vtable-general

I can include a reference to that document in the comment perhaps?

266 ↗

(On Diff #88056)

Sure, we can share any appropriate code once the constant arguments on edges feature lands.

288 ↗

(On Diff #88056)

Makes sense. I'll do that in a followup.

355 ↗

(On Diff #88056)

Yes, I'll remove these.

llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp

4854 ↗

(On Diff #88056)

Will do.

[mehdi_amini]

llvm/trunk/include/llvm/IR/ModuleSummaryIndex.h

253 ↗

(On Diff #88056)

I'm a big fan of adding reference to external document/standard in comments indeed. That helps readers that aren't as familiar with the standard. Thks.

[pcc]

I addressed the post-commit review comments in r294822.

llvm/include/llvm/Bitcode/LLVMBitCodes.h

enum GlobalValueSummarySymtabCodes {
   // ALIAS: [valueid, flags, valueid]
   FS_ALIAS = 7,
   // COMBINED_ALIAS: [valueid, modid, flags, valueid]
   FS_COMBINED_ALIAS = 8,
   // COMBINED_ORIGINAL_NAME: [original_name_hash]
   FS_COMBINED_ORIGINAL_NAME = 9,
   // VERSION of the summary, bumped when adding flags for instance.
   FS_VERSION = 10,
-  // The list of llvm.type.test type identifiers used by the following function.
+  // The list of llvm.type.test type identifiers used by the following function
+  // that are used other than by an llvm.assume.
+  // [n x typeid]
   FS_TYPE_TESTS = 11,
+  // The list of virtual calls made by this function using
+  // llvm.assume(llvm.type.test) intrinsics that do not have constant integer
+  // arguments.
+  // [n x (typeid, offset)]
+  FS_TYPE_TEST_ASSUME_VCALLS = 12,
+  // The list of virtual calls made by this function using
+  // llvm.type.checked.load intrinsics that do not have constant integer
+  // arguments.
+  // [n x (typeid, offset)]
+  FS_TYPE_CHECKED_LOAD_VCALLS = 13,
+  // Identifies a virtual call made by this function using a
+  // llvm.assume(llvm.type.test) intrinsic with constant integer
+  // arguments.
+  // [typeid, offset, n x arg]
+  FS_TYPE_TEST_ASSUME_CONST_VCALL = 14,
+  // Identifies a virtual call made by this function using a
+  // llvm.type.checked.load intrinsic with constant integer arguments.
+  // [typeid, offset, n x arg]
+  FS_TYPE_CHECKED_LOAD_CONST_VCALL = 15,
 };
 
 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]

llvm/include/llvm/IR/ModuleSummaryIndex.h

 
 /// \brief Function summary information to aid decisions and implementation of
 /// importing.
 class FunctionSummary : public GlobalValueSummary {
 public:
   /// <CalleeValueInfo, CalleeInfo> call edge pair.
   typedef std::pair<ValueInfo, CalleeInfo> EdgeTy;
 
+  /// An "identifier" for a virtual function. This contains the type identifier
+  /// represented as a GUID and the offset from the address point to the virtual
+  /// function pointer.
+  struct VFuncId {
+    GlobalValue::GUID GUID;
+    uint64_t Offset;
+  };
+
+  /// A specification for a virtual function call with constant integer
+  /// arguments. This is used to perform virtual constant propagation on the
+  /// summary.
+  struct ConstVCall {
+    VFuncId VFunc;
+    std::vector<uint64_t> Args;
+  };
+
 private:
   /// Number of instructions (ignoring debug instructions, e.g.) computed
   /// during the initial compile step when the summary index is first built.
   unsigned InstCount;
 
   /// List of <CalleeValueInfo, CalleeInfo> call edge pairs from this function.
   std::vector<EdgeTy> CallGraphEdgeList;
 
-  /// List of type identifiers used by this function, represented as GUIDs.
-  std::vector<GlobalValue::GUID> TypeIdList;
+  /// List of type identifiers used by this function in llvm.type.test
+  /// intrinsics other than by an llvm.assume intrinsic, represented as GUIDs.
+  std::vector<GlobalValue::GUID> TypeTests;
+
+  /// List of virtual calls made by this function using (respectively)
+  /// llvm.assume(llvm.type.test) or llvm.type.checked.load intrinsics that do
+  /// not have constant integer arguments.
+  std::vector<VFuncId> TypeTestAssumeVCalls, TypeCheckedLoadVCalls;
+
+  /// List of virtual calls made by this function using (respectively)
+  /// llvm.assume(llvm.type.test) or llvm.type.checked.load intrinsics with
+  /// constant integer arguments.
+  std::vector<ConstVCall> TypeTestAssumeConstVCalls, TypeCheckedLoadConstVCalls;
 
 public:
   /// Summary constructors.
   FunctionSummary(GVFlags Flags, unsigned NumInsts, std::vector<ValueInfo> Refs,
                   std::vector<EdgeTy> CGEdges,
-                  std::vector<GlobalValue::GUID> TypeIds)
+                  std::vector<GlobalValue::GUID> TypeTests,
+                  std::vector<VFuncId> TypeTestAssumeVCalls,
+                  std::vector<VFuncId> TypeCheckedLoadVCalls,
+                  std::vector<ConstVCall> TypeTestAssumeConstVCalls,
+                  std::vector<ConstVCall> TypeCheckedLoadConstVCalls)
       : GlobalValueSummary(FunctionKind, Flags, std::move(Refs)),
         InstCount(NumInsts), CallGraphEdgeList(std::move(CGEdges)),
-        TypeIdList(std::move(TypeIds)) {}
+        TypeTests(std::move(TypeTests)),
+        TypeTestAssumeVCalls(std::move(TypeTestAssumeVCalls)),
+        TypeCheckedLoadVCalls(std::move(TypeCheckedLoadVCalls)),
+        TypeTestAssumeConstVCalls(std::move(TypeTestAssumeConstVCalls)),
+        TypeCheckedLoadConstVCalls(std::move(TypeCheckedLoadConstVCalls)) {}
 
   /// Check if this is a function summary.
   static bool classof(const GlobalValueSummary *GVS) {
     return GVS->getSummaryKind() == FunctionKind;
   }
 
   /// Get the instruction count recorded for this function.
   unsigned instCount() const { return InstCount; }
 
   /// Return the list of <CalleeValueInfo, CalleeInfo> pairs.
   ArrayRef<EdgeTy> calls() const { return CallGraphEdgeList; }
 
-  /// Returns the list of type identifiers used by this function.
-  ArrayRef<GlobalValue::GUID> type_tests() const { return TypeIdList; }
+  /// Returns the list of type identifiers used by this function in llvm.type.test
+  /// intrinsics other than by an llvm.assume intrinsic, represented as GUIDs.
+  ArrayRef<GlobalValue::GUID> type_tests() const { return TypeTests; }
+
+  /// Returns the list of virtual calls made by this function using
+  /// llvm.assume(llvm.type.test) intrinsics that do not have constant integer
+  /// arguments.
+  ArrayRef<VFuncId> type_test_assume_vcalls() const { return TypeTestAssumeVCalls; }
+
+  /// Returns the list of virtual calls made by this function using
+  /// llvm.type.checked.load intrinsics that do not have constant integer
+  /// arguments.
+  ArrayRef<VFuncId> type_checked_load_vcalls() const { return TypeCheckedLoadVCalls; }
+
+  /// Returns the list of virtual calls made by this function using
+  /// llvm.assume(llvm.type.test) intrinsics with constant integer arguments.
+  ArrayRef<ConstVCall> type_test_assume_const_vcalls() const {
+    return TypeTestAssumeConstVCalls;
+  }
+
+  /// Returns the list of virtual calls made by this function using
+  /// llvm.type.checked.load intrinsics with constant integer arguments.
+  ArrayRef<ConstVCall> type_checked_load_const_vcalls() const {
+    return TypeCheckedLoadConstVCalls;
+  }
+};
+
+template <> struct DenseMapInfo<FunctionSummary::VFuncId> {
+  static inline FunctionSummary::VFuncId getEmptyKey() { return {0, uint64_t(-1)}; }
+  static inline FunctionSummary::VFuncId getTombstoneKey() { return {0, uint64_t(-2)}; }
+  static bool isEqual(FunctionSummary::VFuncId L, FunctionSummary::VFuncId R) {
+    return L.GUID == R.GUID && L.Offset == R.Offset;
+  }
+  static unsigned getHashValue(FunctionSummary::VFuncId I) { return I.GUID; }
+};
+
+template <> struct DenseMapInfo<FunctionSummary::ConstVCall> {
+  static inline FunctionSummary::ConstVCall getEmptyKey() {
+    return {{0, uint64_t(-1)}, {}};
+  }
+  static inline FunctionSummary::ConstVCall getTombstoneKey() {
+    return {{0, uint64_t(-2)}, {}};
+  }
+  static bool isEqual(FunctionSummary::ConstVCall L,
+                      FunctionSummary::ConstVCall R) {
+    return DenseMapInfo<FunctionSummary::VFuncId>::isEqual(L.VFunc, R.VFunc) &&
+           L.Args == R.Args;
+  }
+  static unsigned getHashValue(FunctionSummary::ConstVCall I) {
+    return I.VFunc.GUID;
+  }
 };
 
 /// \brief Global variable summary information to aid decisions and
 /// implementation of importing.
 ///
 /// Currently this doesn't add anything to the base \p GlobalValueSummary,
 /// but is a placeholder as additional info may be added to the summary
 /// for variables.

llvm/include/llvm/IR/ModuleSummaryIndexYAML.h

if (Key.getAsInteger(0, KeyInt)) {
       return;
     }
     auto &Elem = V[KeyInt];
     for (auto &FSum : FSums) {
       GlobalValueSummary::GVFlags GVFlags(GlobalValue::ExternalLinkage, false,
                                           false);
       Elem.push_back(llvm::make_unique<FunctionSummary>(
           GVFlags, 0, ArrayRef<ValueInfo>{},
-          ArrayRef<FunctionSummary::EdgeTy>{}, std::move(FSum.TypeTests)));
+          ArrayRef<FunctionSummary::EdgeTy>{}, std::move(FSum.TypeTests),
+          ArrayRef<FunctionSummary::VFuncId>{},
+          ArrayRef<FunctionSummary::VFuncId>{},
+          ArrayRef<FunctionSummary::ConstVCall>{},
+          ArrayRef<FunctionSummary::ConstVCall>{}));
     }
   }
   static void output(IO &io, GlobalValueSummaryMapTy &V) {
     for (auto &P : V) {
       std::vector<FunctionSummaryYaml> FSums;
       for (auto &Sum : P.second) {
         if (auto *FSum = dyn_cast<FunctionSummary>(Sum.get()))
           FSums.push_back(FunctionSummaryYaml{FSum->type_tests()});

llvm/lib/Analysis/ModuleSummaryAnalysis.cpp

if (PSI->isColdCount(ProfileCount))
     return CalleeInfo::HotnessType::Cold;
   return CalleeInfo::HotnessType::None;
 }
 
 static bool isNonRenamableLocal(const GlobalValue &GV) {
   return GV.hasSection() && GV.hasLocalLinkage();
 }
 
+static void addVCallToSet(DevirtCallSite Call, GlobalValue::GUID Guid,
+                          SetVector<FunctionSummary::VFuncId> &VCalls,
+                          SetVector<FunctionSummary::ConstVCall> &ConstVCalls) {
+  std::vector<uint64_t> Args;
+  for (auto &Arg : make_range(Call.CS.arg_begin() + 1, Call.CS.arg_end())) {
+    auto *CI = dyn_cast<ConstantInt>(Arg);
+    if (!CI || CI->getBitWidth() > 64) {
+      VCalls.insert({Guid, Call.Offset});
+      return;
+    }
+    Args.push_back(CI->getZExtValue());
+  }
+  ConstVCalls.insert({{Guid, Call.Offset}, std::move(Args)});
+}
+
+static void addVCallsToSet(ArrayRef<DevirtCallSite> Calls,
+                           GlobalValue::GUID Guid,
+                           SetVector<FunctionSummary::VFuncId> &VCalls,
+                           SetVector<FunctionSummary::ConstVCall> &ConstVCalls) {
+  for (auto &Call : Calls)
+    addVCallToSet(Call, Guid, VCalls, ConstVCalls);
+}
+
 static void
 computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
                        const Function &F, BlockFrequencyInfo *BFI,
                        ProfileSummaryInfo *PSI, bool HasLocalsInUsed,
                        DenseSet<GlobalValue::GUID> &CantBePromoted) {
   // Summary not currently supported for anonymous functions, they should
   // have been named.
   assert(F.hasName());
 
   unsigned NumInsts = 0;
   // Map from callee ValueId to profile count. Used to accumulate profile
   // counts for all static calls to a given callee.
   MapVector<ValueInfo, CalleeInfo> CallGraphEdges;
   SetVector<ValueInfo> RefEdges;
   SetVector<GlobalValue::GUID> TypeTests;
+  SetVector<FunctionSummary::VFuncId> TypeTestAssumeVCalls, TypeCheckedLoadVCalls;
+  SetVector<FunctionSummary::ConstVCall> TypeTestAssumeConstVCalls,
+      TypeCheckedLoadConstVCalls;
   ICallPromotionAnalysis ICallAnalysis;
 
   bool HasInlineAsmMaybeReferencingInternal = false;
   SmallPtrSet<const User *, 8> Visited;
   for (const BasicBlock &BB : F)
     for (const Instruction &I : BB) {
       if (isa<DbgInfoIntrinsic>(I))
         continue;
for (const Instruction &I : BB) {
       if (auto *GA = dyn_cast<GlobalAlias>(CalledValue)) {
         assert(!CalledFunction && "Expected null called function in callsite for alias");
         CalledFunction = dyn_cast<Function>(GA->getBaseObject());
       }
       // Check if this is a direct call to a known function or a known
       // intrinsic, or an indirect call with profile data.
       if (CalledFunction) {
         if (CalledFunction->isIntrinsic()) {
-          if (CalledFunction->getIntrinsicID() != Intrinsic::type_test)
+          switch (CalledFunction->getIntrinsicID()) {
+          case Intrinsic::type_test: {
+            auto *TypeMDVal = cast<MetadataAsValue>(CI->getArgOperand(1));
+            auto *TypeId = dyn_cast<MDString>(TypeMDVal->getMetadata());
+            if (!TypeId)
               continue;
+            GlobalValue::GUID Guid = GlobalValue::getGUID(TypeId->getString());
+
             // Produce a summary from type.test intrinsics. We only summarize
             // type.test intrinsics that are used other than by an llvm.assume
             // intrinsic. Intrinsics that are assumed are relevant only to the
             // devirtualization pass, not the type test lowering pass.
-          bool HasNonAssumeUses = llvm::any_of(CI->uses(), [](const Use &CIU) {
+            bool HasNonAssumeUses =
+                llvm::any_of(CI->uses(), [](const Use &CIU) {
                   auto *AssumeCI = dyn_cast<CallInst>(CIU.getUser());
                   if (!AssumeCI)
                     return true;
                   Function *F = AssumeCI->getCalledFunction();
                   return !F || F->getIntrinsicID() != Intrinsic::assume;
                 });
-          if (HasNonAssumeUses) {
-            auto *TypeMDVal = cast<MetadataAsValue>(CI->getArgOperand(1));
-            if (auto *TypeId = dyn_cast<MDString>(TypeMDVal->getMetadata()))
-              TypeTests.insert(GlobalValue::getGUID(TypeId->getString()));
+            if (HasNonAssumeUses)
+              TypeTests.insert(Guid);
+
+            SmallVector<DevirtCallSite, 4> DevirtCalls;
+            SmallVector<CallInst *, 4> Assumes;
+            findDevirtualizableCallsForTypeTest(DevirtCalls, Assumes, CI);
+            addVCallsToSet(DevirtCalls, Guid, TypeTestAssumeVCalls,
+                           TypeTestAssumeConstVCalls);
+
+            break;
+          }
+
+          case Intrinsic::type_checked_load: {
+            auto *TypeMDVal = cast<MetadataAsValue>(CI->getArgOperand(2));
+            auto *TypeId = dyn_cast<MDString>(TypeMDVal->getMetadata());
+            if (!TypeId)
+              continue;
+            GlobalValue::GUID Guid = GlobalValue::getGUID(TypeId->getString());
+
+            SmallVector<DevirtCallSite, 4> DevirtCalls;
+            SmallVector<Instruction *, 4> LoadedPtrs;
+            SmallVector<Instruction *, 4> Preds;
+            bool HasNonCallUses = false;
+            findDevirtualizableCallsForTypeCheckedLoad(
+                DevirtCalls, LoadedPtrs, Preds, HasNonCallUses, CI);
+            // Any non-call uses of the result of llvm.type.checked.load will
+            // prevent us from optimizing away the llvm.type.test.
+            if (HasNonCallUses)
+              TypeTests.insert(Guid);
+            addVCallsToSet(DevirtCalls, Guid, TypeCheckedLoadVCalls,
+                           TypeCheckedLoadConstVCalls);
+
+            break;
+          }
+          default:
+            break;
           }
+          continue;
         }
         // We should have named any anonymous globals
         assert(CalledFunction->hasName());
         auto ScaledCount = BFI ? BFI->getBlockProfileCount(&BB) : None;
         auto Hotness = ScaledCount ? getHotness(ScaledCount.getValue(), PSI)
                                    : CalleeInfo::HotnessType::Unknown;
 
         // Use the original CalledValue, in case it was an alias. We want
bool NotEligibleForImport =
       NonRenamableLocal || HasInlineAsmMaybeReferencingInternal ||
       // Inliner doesn't handle variadic functions.
       // FIXME: refactor this to use the same code that inliner is using.
       F.isVarArg();
   GlobalValueSummary::GVFlags Flags(F.getLinkage(), NotEligibleForImport,
                                     /* LiveRoot = */ false);
   auto FuncSummary = llvm::make_unique<FunctionSummary>(
       Flags, NumInsts, RefEdges.takeVector(), CallGraphEdges.takeVector(),
-      TypeTests.takeVector());
+      TypeTests.takeVector(), TypeTestAssumeVCalls.takeVector(),
+      TypeCheckedLoadVCalls.takeVector(),
+      TypeTestAssumeConstVCalls.takeVector(),
+      TypeCheckedLoadConstVCalls.takeVector());
   if (NonRenamableLocal)
     CantBePromoted.insert(F.getGUID());
   Index.addGlobalValueSummary(F.getName(), std::move(FuncSummary));
 }
 
 static void
 computeVariableSummary(ModuleSummaryIndex &Index, const GlobalVariable &V,
                        DenseSet<GlobalValue::GUID> &CantBePromoted) {
ModuleSymbolTable::CollectAsmSymbols(
                                               /* LiveRoot */ true);
           CantBePromoted.insert(GlobalValue::getGUID(Name));
           // Create the appropriate summary type.
           if (isa<Function>(GV)) {
             std::unique_ptr<FunctionSummary> Summary =
                 llvm::make_unique<FunctionSummary>(
                     GVFlags, 0, ArrayRef<ValueInfo>{},
                     ArrayRef<FunctionSummary::EdgeTy>{},
-                    ArrayRef<GlobalValue::GUID>{});
+                    ArrayRef<GlobalValue::GUID>{},
+                    ArrayRef<FunctionSummary::VFuncId>{},
+                    ArrayRef<FunctionSummary::VFuncId>{},
+                    ArrayRef<FunctionSummary::ConstVCall>{},
+                    ArrayRef<FunctionSummary::ConstVCall>{});
             Index.addGlobalValueSummary(Name, std::move(Summary));
           } else {
             std::unique_ptr<GlobalVarSummary> Summary =
                 llvm::make_unique<GlobalVarSummary>(GVFlags,
                                                     ArrayRef<ValueInfo>{});
             Index.addGlobalValueSummary(Name, std::move(Summary));
           }
         });

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

return error("Invalid summary version " + Twine(Version) +
                  ", 1, 2 or 3 expected");
   Record.clear();
 
   // Keep around the last seen summary to be used when we see an optional
   // "OriginalName" attachement.
   GlobalValueSummary *LastSeenSummary = nullptr;
   bool Combined = false;
   std::vector<GlobalValue::GUID> PendingTypeTests;
+  std::vector<FunctionSummary::VFuncId> PendingTypeTestAssumeVCalls,
+      PendingTypeCheckedLoadVCalls;
+  std::vector<FunctionSummary::ConstVCall> PendingTypeTestAssumeConstVCalls,
+      PendingTypeCheckedLoadConstVCalls;
 
   while (true) {
     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: {
       std::vector<ValueInfo> Refs = makeRefList(
           ArrayRef<uint64_t>(Record).slice(RefListStartIndex, NumRefs));
       bool HasProfile = (BitCode == bitc::FS_PERMODULE_PROFILE);
       std::vector<FunctionSummary::EdgeTy> Calls = makeCallList(
           ArrayRef<uint64_t>(Record).slice(CallGraphEdgeStartIndex),
           IsOldProfileFormat, HasProfile);
       auto FS = llvm::make_unique<FunctionSummary>(
           Flags, InstCount, std::move(Refs), std::move(Calls),
-          std::move(PendingTypeTests));
+          std::move(PendingTypeTests), std::move(PendingTypeTestAssumeVCalls),
+          std::move(PendingTypeCheckedLoadVCalls),
+          std::move(PendingTypeTestAssumeConstVCalls),
+          std::move(PendingTypeCheckedLoadConstVCalls));
       PendingTypeTests.clear();
+      PendingTypeTestAssumeVCalls.clear();
+      PendingTypeCheckedLoadVCalls.clear();
+      PendingTypeTestAssumeConstVCalls.clear();
+      PendingTypeCheckedLoadConstVCalls.clear();
       auto GUID = getGUIDFromValueId(ValueID);
       FS->setModulePath(TheIndex.addModulePath(ModulePath, 0)->first());
       FS->setOriginalName(GUID.second);
       TheIndex.addGlobalValueSummary(GUID.first, std::move(FS));
       break;
     }
     // FS_ALIAS: [valueid, flags, valueid]
     // Aliases must be emitted (and parsed) after all FS_PERMODULE entries, as
case bitc::FS_COMBINED_PROFILE: {
           ArrayRef<uint64_t>(Record).slice(RefListStartIndex, NumRefs));
       bool HasProfile = (BitCode == bitc::FS_COMBINED_PROFILE);
       std::vector<FunctionSummary::EdgeTy> Edges = makeCallList(
           ArrayRef<uint64_t>(Record).slice(CallGraphEdgeStartIndex),
           IsOldProfileFormat, HasProfile);
       GlobalValue::GUID GUID = getGUIDFromValueId(ValueID).first;
       auto FS = llvm::make_unique<FunctionSummary>(
           Flags, InstCount, std::move(Refs), std::move(Edges),
-          std::move(PendingTypeTests));
+          std::move(PendingTypeTests), std::move(PendingTypeTestAssumeVCalls),
+          std::move(PendingTypeCheckedLoadVCalls),
+          std::move(PendingTypeTestAssumeConstVCalls),
+          std::move(PendingTypeCheckedLoadConstVCalls));
       PendingTypeTests.clear();
+      PendingTypeTestAssumeVCalls.clear();
+      PendingTypeCheckedLoadVCalls.clear();
+      PendingTypeTestAssumeConstVCalls.clear();
+      PendingTypeCheckedLoadConstVCalls.clear();
       LastSeenSummary = FS.get();
       FS->setModulePath(ModuleIdMap[ModuleId]);
       TheIndex.addGlobalValueSummary(GUID, std::move(FS));
       Combined = true;
       break;
     }
     // FS_COMBINED_ALIAS: [valueid, modid, flags, valueid]
     // Aliases must be emitted (and parsed) after all FS_COMBINED entries, as
case bitc::FS_COMBINED_ORIGINAL_NAME: {
       break;
     }
     case bitc::FS_TYPE_TESTS: {
       assert(PendingTypeTests.empty());
       PendingTypeTests.insert(PendingTypeTests.end(), Record.begin(),
                               Record.end());
       break;
     }
+    case bitc::FS_TYPE_TEST_ASSUME_VCALLS: {
+      assert(PendingTypeTestAssumeVCalls.empty());
+      for (unsigned I = 0; I != Record.size(); I += 2)
+        PendingTypeTestAssumeVCalls.push_back({Record[I], Record[I+1]});
+      break;
+    }
+    case bitc::FS_TYPE_CHECKED_LOAD_VCALLS: {
+      assert(PendingTypeCheckedLoadVCalls.empty());
+      for (unsigned I = 0; I != Record.size(); I += 2)
+        PendingTypeCheckedLoadVCalls.push_back({Record[I], Record[I+1]});
+      break;
+    }
+    case bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL: {
+      PendingTypeTestAssumeConstVCalls.push_back(
+          {{Record[0], Record[1]}, {Record.begin() + 2, Record.end()}});
+      break;
+    }
+    case bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL: {
+      PendingTypeCheckedLoadConstVCalls.push_back(
+          {{Record[0], Record[1]}, {Record.begin() + 2, Record.end()}});
+      break;
+    }
     }
   }
   llvm_unreachable("Exit infinite loop");
 }
 
 // Parse the  module string table block into the Index.
 // This populates the ModulePathStringTable map in the index.
 Error ModuleSummaryIndexBitcodeReader::parseModuleStringTable() {

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

if (!AllZero) {
       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
     }
 
     Vals.clear();
   }
   Stream.ExitBlock();
 }
 
+static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
+                                             FunctionSummary *FS) {
+  if (!FS->type_tests().empty())
+    Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
+
+  SmallVector<uint64_t, 64> Record;
+
+  auto WriteVFuncIdVec = [&](uint64_t Ty,
+                             ArrayRef<FunctionSummary::VFuncId> VFs) {
+    if (VFs.empty())
+      return;
+    Record.clear();
+    for (auto &VF : VFs) {
+      Record.push_back(VF.GUID);
+      Record.push_back(VF.Offset);
+    }
+    Stream.EmitRecord(Ty, Record);
+  };
+
+  WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS, FS->type_test_assume_vcalls());
+  WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS, FS->type_checked_load_vcalls());
+
+  auto WriteConstVCallVec = [&](uint64_t Ty,
+                                ArrayRef<FunctionSummary::ConstVCall> VCs) {
+    for (auto &VC : VCs) {
+      Record.clear();
+      Record.push_back(VC.VFunc.GUID);
+      Record.push_back(VC.VFunc.Offset);
+      Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
+      Stream.EmitRecord(Ty, Record);
+    }
+  };
+
+  WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
+                     FS->type_test_assume_const_vcalls());
+  WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
+                     FS->type_checked_load_const_vcalls());
+}
+
 // Helper to emit a single function summary record.
 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
     const Function &F) {
   NameVals.push_back(ValueID);
 
   FunctionSummary *FS = cast<FunctionSummary>(Summary);
-  if (!FS->type_tests().empty())
-    Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
+  writeFunctionTypeMetadataRecords(Stream, FS);
 
   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
   NameVals.push_back(FS->instCount());
   NameVals.push_back(FS->refs().size());
 
   for (auto &RI : FS->refs())
     NameVals.push_back(VE.getValueID(RI.getValue()));
 
if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
                         FSModRefsAbbrev);
       NameVals.clear();
       MaybeEmitOriginalName(*S);
       continue;
     }
 
     auto *FS = cast<FunctionSummary>(S);
-    if (!FS->type_tests().empty())
-      Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
+    writeFunctionTypeMetadataRecords(Stream, FS);
 
     NameVals.push_back(ValueId);
     NameVals.push_back(Index.getModuleId(FS->modulePath()));
     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
     NameVals.push_back(FS->instCount());
     NameVals.push_back(FS->refs().size());
 
     for (auto &RI : FS->refs()) {

llvm/test/Bitcode/thinlto-type-vcalls.ll

+; RUN: opt -module-summary %s -o %t.o
+; RUN: llvm-bcanalyzer -dump %t.o | FileCheck %s
+; RUN: llvm-lto -thinlto -o %t2 %t.o
+; RUN: llvm-bcanalyzer -dump %t2.thinlto.bc | FileCheck --check-prefix=COMBINED %s
+
+target datalayout = "e-p:64:64"
+target triple = "x86_64-unknown-linux-gnu"
+
+; COMBINED:      <TYPE_TEST_ASSUME_VCALLS op0=6699318081062747564 op1=16/>
+; COMBINED-NEXT: <COMBINED
+; COMBINED-NEXT: <TYPE_CHECKED_LOAD_VCALLS op0=6699318081062747564 op1=16/>
+; COMBINED-NEXT: <COMBINED
+; COMBINED-NEXT: <TYPE_TEST_ASSUME_VCALLS op0=6699318081062747564 op1=24 op2=-2012135647395072713 op3=32/>
+; COMBINED-NEXT: <COMBINED
+; COMBINED-NEXT: <TYPE_TEST_ASSUME_CONST_VCALL op0=6699318081062747564 op1=16 op2=42/>
+; COMBINED-NEXT: <TYPE_TEST_ASSUME_CONST_VCALL op0=6699318081062747564 op1=24 op2=43/>
+; COMBINED-NEXT: <COMBINED
+; COMBINED-NEXT: <TYPE_CHECKED_LOAD_CONST_VCALL op0=6699318081062747564 op1=16 op2=42/>
+; COMBINED-NEXT: <COMBINED
+; COMBINED-NEXT: <TYPE_TESTS op0=7546896869197086323/>
+; COMBINED-NEXT: <COMBINED
+
+; CHECK: <TYPE_TEST_ASSUME_VCALLS op0=6699318081062747564 op1=16/>
+define void @f1([3 x i8*]* %vtable) {
+  %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
+  %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"foo")
+  call void @llvm.assume(i1 %p)
+  %fptrptr = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 2
+  %fptr = load i8*, i8** %fptrptr
+  %fptr_casted = bitcast i8* %fptr to void (i8*, i32)*
+  call void %fptr_casted(i8* null, i32 undef)
+  ret void
+}
+
+; CHECK: <TYPE_TEST_ASSUME_VCALLS op0=6699318081062747564 op1=24 op2=-2012135647395072713 op3=32/>
+define void @f2([3 x i8*]* %vtable, [3 x i8*]* %vtable2) {
+  %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
+  %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"foo")
+  call void @llvm.assume(i1 %p)
+  %fptrptr = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 3
+  %fptr = load i8*, i8** %fptrptr
+  %fptr_casted = bitcast i8* %fptr to void (i8*, i32)*
+  call void %fptr_casted(i8* null, i32 undef)
+
+  %vtablei82 = bitcast [3 x i8*]* %vtable2 to i8*
+  %p2 = call i1 @llvm.type.test(i8* %vtablei82, metadata !"bar")
+  call void @llvm.assume(i1 %p2)
+  %fptrptr2 = getelementptr [3 x i8*], [3 x i8*]* %vtable2, i32 0, i32 4
+  %fptr2 = load i8*, i8** %fptrptr2
+  %fptr_casted2 = bitcast i8* %fptr2 to void (i8*, i128)*
+  call void %fptr_casted2(i8* null, i128 0)
+
+  ret void
+}
+
+; CHECK: <TYPE_CHECKED_LOAD_VCALLS op0=6699318081062747564 op1=16/>
+define void @f3(i8* %vtable) {
+  %pair = call {i8*, i1} @llvm.type.checked.load(i8* %vtable, i32 16, metadata !"foo")
+  %fptr = extractvalue {i8*, i1} %pair, 0
+  %fptr_casted = bitcast i8* %fptr to void (i8*, i32)*
+  call void %fptr_casted(i8* null, i32 undef)
+  ret void
+}
+
+; CHECK: <TYPE_TEST_ASSUME_CONST_VCALL op0=6699318081062747564 op1=16 op2=42/>
+; CHECK-NEXT: <TYPE_TEST_ASSUME_CONST_VCALL op0=6699318081062747564 op1=24 op2=43/>
+define void @f4([3 x i8*]* %vtable, [3 x i8*]* %vtable2) {
+  %vtablei8 = bitcast [3 x i8*]* %vtable to i8*
+  %p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"foo")
+  call void @llvm.assume(i1 %p)
+  %fptrptr = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 2
+  %fptr = load i8*, i8** %fptrptr
+  %fptr_casted = bitcast i8* %fptr to void (i8*, i32)*
+  call void %fptr_casted(i8* null, i32 42)
+
+  %vtablei82 = bitcast [3 x i8*]* %vtable2 to i8*
+  %p2 = call i1 @llvm.type.test(i8* %vtablei82, metadata !"foo")
+  call void @llvm.assume(i1 %p2)
+  %fptrptr2 = getelementptr [3 x i8*], [3 x i8*]* %vtable2, i32 0, i32 3
+  %fptr2 = load i8*, i8** %fptrptr2
+  %fptr_casted2 = bitcast i8* %fptr2 to void (i8*, i32)*
+  call void %fptr_casted2(i8* null, i32 43)
+  ret void
+}
+
+; CHECK: <TYPE_CHECKED_LOAD_CONST_VCALL op0=6699318081062747564 op1=16 op2=42/>
+define void @f5(i8* %vtable) {
+  %pair = call {i8*, i1} @llvm.type.checked.load(i8* %vtable, i32 16, metadata !"foo")
+  %fptr = extractvalue {i8*, i1} %pair, 0
+  %fptr_casted = bitcast i8* %fptr to void (i8*, i32)*
+  call void %fptr_casted(i8* null, i32 42)
+  ret void
+}
+
+; CHECK-NOT: <TYPE_CHECKED_LOAD_CONST_VCALL op0=7546896869197086323
+; CHECK: <TYPE_TESTS op0=7546896869197086323/>
+; CHECK-NOT: <TYPE_CHECKED_LOAD_CONST_VCALL op0=7546896869197086323
+define {i8*, i1} @f6(i8* %vtable) {
+  %pair = call {i8*, i1} @llvm.type.checked.load(i8* %vtable, i32 16, metadata !"baz")
+  ret {i8*, i1} %pair
+}
+
+declare i1 @llvm.type.test(i8*, metadata) nounwind readnone
+declare void @llvm.assume(i1)
+declare {i8*, i1} @llvm.type.checked.load(i8*, i32, metadata)

llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp

default:
       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)
       STRINGIFY_CODE(FS, VERSION)
       STRINGIFY_CODE(FS, TYPE_TESTS)
+      STRINGIFY_CODE(FS, TYPE_TEST_ASSUME_VCALLS)
+      STRINGIFY_CODE(FS, TYPE_CHECKED_LOAD_VCALLS)
+      STRINGIFY_CODE(FS, TYPE_TEST_ASSUME_CONST_VCALL)
+      STRINGIFY_CODE(FS, TYPE_CHECKED_LOAD_CONST_VCALL)
     }
   case bitc::METADATA_ATTACHMENT_ID:
     switch(CodeID) {
     default:return nullptr;
       STRINGIFY_CODE(METADATA, ATTACHMENT)
     }
   case bitc::METADATA_BLOCK_ID:
     switch(CodeID) {