diff --git a/clang/test/CodeGenCXX/vcall-visibility-metadata.cpp b/clang/test/CodeGenCXX/vcall-visibility-metadata.cpp
--- a/clang/test/CodeGenCXX/vcall-visibility-metadata.cpp
+++ b/clang/test/CodeGenCXX/vcall-visibility-metadata.cpp
@@ -1,6 +1,9 @@
 // RUN: %clang_cc1 -flto -flto-unit -triple x86_64-unknown-linux -emit-llvm -fvirtual-function-elimination -fwhole-program-vtables -o - %s | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-VFE
 // RUN: %clang_cc1 -flto -flto-unit -triple x86_64-unknown-linux -emit-llvm -fwhole-program-vtables -o - %s | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOVFE
 
+// Check that in ThinLTO we also get vcall_visibility summary entries in the bitcode
+// RUN: %clang_cc1 -flto=thin -flto-unit -triple x86_64-unknown-linux -emit-llvm-bc -fwhole-program-vtables -o - %s | llvm-dis -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOVFE --check-prefix=CHECK-SUMMARY
+
 
 // Anonymous namespace.
 namespace {
@@ -88,3 +91,11 @@
 // CHECK-DAG: [[VIS_TU]] = !{i64 2}
 // CHECK-VFE-DAG: !{i32 1, !"Virtual Function Elim", i32 1}
 // CHECK-NOVFE-DAG: !{i32 1, !"Virtual Function Elim", i32 0}
+
+// CHECK-SUMMARY-DAG: gv: (name: "_ZTV1B", {{.*}} vcall_visibility: 1
+// CHECK-SUMMARY-DAG: gv: (name: "_ZTVN12_GLOBAL__N_11FE", {{.*}} vcall_visibility: 0
+// CHECK-SUMMARY-DAG: gv: (name: "_ZTV1D", {{.*}} vcall_visibility: 0
+// CHECK-SUMMARY-DAG: gv: (name: "_ZTV1C", {{.*}} vcall_visibility: 0
+// CHECK-SUMMARY-DAG: gv: (name: "_ZTV1E", {{.*}} vcall_visibility: 0
+// CHECK-SUMMARY-DAG: gv: (name: "_ZTVN12_GLOBAL__N_11AE", {{.*}} vcall_visibility: 2
+// CHECK-SUMMARY-DAG: gv: (name: "_ZTVN12_GLOBAL__N_11GE", {{.*}} vcall_visibility: 1
diff --git a/llvm/include/llvm/IR/ModuleSummaryIndex.h b/llvm/include/llvm/IR/ModuleSummaryIndex.h
--- a/llvm/include/llvm/IR/ModuleSummaryIndex.h
+++ b/llvm/include/llvm/IR/ModuleSummaryIndex.h
@@ -757,14 +757,20 @@
 
 public:
   struct GVarFlags {
-    GVarFlags(bool ReadOnly, bool WriteOnly)
-        : MaybeReadOnly(ReadOnly), MaybeWriteOnly(WriteOnly) {}
+    GVarFlags(
+        bool ReadOnly, bool WriteOnly,
+        GlobalObject::VCallVisibility Vis = GlobalObject::VCallVisibilityPublic)
+        : MaybeReadOnly(ReadOnly), MaybeWriteOnly(WriteOnly),
+          VCallVisibility(Vis) {}
 
     // In permodule summaries both MaybeReadOnly and MaybeWriteOnly
     // bits are set, because attribute propagation occurs later on
     // thin link phase.
     unsigned MaybeReadOnly : 1;
     unsigned MaybeWriteOnly : 1;
+    // Set from metadata on vtable definitions during the module summary
+    // analysis.
+    unsigned VCallVisibility : 2;
   } VarFlags;
 
   GlobalVarSummary(GVFlags Flags, GVarFlags VarFlags,
@@ -782,6 +788,12 @@
   void setWriteOnly(bool WO) { VarFlags.MaybeWriteOnly = WO; }
   bool maybeReadOnly() const { return VarFlags.MaybeReadOnly; }
   bool maybeWriteOnly() const { return VarFlags.MaybeWriteOnly; }
+  void setVCallVisibility(GlobalObject::VCallVisibility Vis) {
+    VarFlags.VCallVisibility = Vis;
+  }
+  GlobalObject::VCallVisibility vCallVisibility() const {
+    return (GlobalObject::VCallVisibility)VarFlags.VCallVisibility;
+  }
 
   void setVTableFuncs(VTableFuncList Funcs) {
     assert(!VTableFuncs);
diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
--- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -599,7 +599,8 @@
   bool CanBeInternalized =
       !V.hasComdat() && !V.hasAppendingLinkage() && !V.isInterposable() &&
       !V.hasAvailableExternallyLinkage() && !V.hasDLLExportStorageClass();
-  GlobalVarSummary::GVarFlags VarFlags(CanBeInternalized, CanBeInternalized);
+  GlobalVarSummary::GVarFlags VarFlags(CanBeInternalized, CanBeInternalized,
+                                       V.getVCallVisibility());
   auto GVarSummary = std::make_unique<GlobalVarSummary>(Flags, VarFlags,
                                                          RefEdges.takeVector());
   if (NonRenamableLocal)
diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -788,6 +788,7 @@
   KEYWORD(sizeM1);
   KEYWORD(bitMask);
   KEYWORD(inlineBits);
+  KEYWORD(vcall_visibility);
   KEYWORD(wpdResolutions);
   KEYWORD(wpdRes);
   KEYWORD(indir);
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -8856,6 +8856,11 @@
         return true;
       GVarFlags.MaybeWriteOnly = Flag;
       break;
+    case lltok::kw_vcall_visibility:
+      if (ParseRest(Flag))
+        return true;
+      GVarFlags.VCallVisibility = Flag;
+      break;
     default:
       return Error(Lex.getLoc(), "expected gvar flag type");
     }
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -421,6 +421,7 @@
   kw_sizeM1,
   kw_bitMask,
   kw_inlineBits,
+  kw_vcall_visibility,
   kw_wpdResolutions,
   kw_wpdRes,
   kw_indir,
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -985,8 +985,9 @@
 
 // Decode the flags for GlobalVariable in the summary
 static GlobalVarSummary::GVarFlags getDecodedGVarFlags(uint64_t RawFlags) {
-  return GlobalVarSummary::GVarFlags((RawFlags & 0x1) ? true : false,
-                                     (RawFlags & 0x2) ? true : false);
+  return GlobalVarSummary::GVarFlags(
+      (RawFlags & 0x1) ? true : false, (RawFlags & 0x2) ? true : false,
+      (GlobalObject::VCallVisibility)(RawFlags >> 2));
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1028,7 +1028,8 @@
 }
 
 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
-  uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1);
+  uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
+                      Flags.VCallVisibility << 2;
   return RawFlags;
 }
 
diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -2896,10 +2896,14 @@
 }
 
 void AssemblyWriter::printGlobalVarSummary(const GlobalVarSummary *GS) {
+  auto VTableFuncs = GS->vTableFuncs();
   Out << ", varFlags: (readonly: " << GS->VarFlags.MaybeReadOnly << ", "
-      << "writeonly: " << GS->VarFlags.MaybeWriteOnly << ")";
+      << "writeonly: " << GS->VarFlags.MaybeWriteOnly;
+  if (!VTableFuncs.empty())
+    Out << ", "
+        << "vcall_visibility: " << GS->VarFlags.VCallVisibility;
+  Out << ")";
 
-  auto VTableFuncs = GS->vTableFuncs();
   if (!VTableFuncs.empty()) {
     Out << ", vTableFuncs: (";
     FieldSeparator FS;
diff --git a/llvm/test/Assembler/thinlto-vtable-summary.ll b/llvm/test/Assembler/thinlto-vtable-summary.ll
--- a/llvm/test/Assembler/thinlto-vtable-summary.ll
+++ b/llvm/test/Assembler/thinlto-vtable-summary.ll
@@ -29,9 +29,9 @@
 
 ^0 = module: (path: "<stdin>", hash: (0, 0, 0, 0, 0))
 ^1 = gv: (name: "_ZN1A1nEi") ; guid = 1621563287929432257
-^2 = gv: (name: "_ZTV1B", summaries: (variable: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0, canAutoHide: 0), varFlags: (readonly: 0, writeonly: 0), vTableFuncs: ((virtFunc: ^3, offset: 16), (virtFunc: ^1, offset: 24)), refs: (^3, ^1)))) ; guid = 5283576821522790367
+^2 = gv: (name: "_ZTV1B", summaries: (variable: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0, canAutoHide: 0), varFlags: (readonly: 0, writeonly: 0, vcall_visibility: 0), vTableFuncs: ((virtFunc: ^3, offset: 16), (virtFunc: ^1, offset: 24)), refs: (^3, ^1)))) ; guid = 5283576821522790367
 ^3 = gv: (name: "_ZN1B1fEi") ; guid = 7162046368816414394
-^4 = gv: (name: "_ZTV1C", summaries: (variable: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0, canAutoHide: 0), varFlags: (readonly: 0, writeonly: 0), vTableFuncs: ((virtFunc: ^5, offset: 16), (virtFunc: ^1, offset: 24)), refs: (^1, ^5)))) ; guid = 13624023785555846296
+^4 = gv: (name: "_ZTV1C", summaries: (variable: (module: ^0, flags: (linkage: external, notEligibleToImport: 0, live: 0, dsoLocal: 0, canAutoHide: 0), varFlags: (readonly: 0, writeonly: 0, vcall_visibility: 0), vTableFuncs: ((virtFunc: ^5, offset: 16), (virtFunc: ^1, offset: 24)), refs: (^1, ^5)))) ; guid = 13624023785555846296
 ^5 = gv: (name: "_ZN1C1fEi") ; guid = 14876272565662207556
 ^6 = typeidCompatibleVTable: (name: "_ZTS1A", summary: ((offset: 16, ^2), (offset: 16, ^4))) ; guid = 7004155349499253778
 ^7 = typeidCompatibleVTable: (name: "_ZTS1B", summary: ((offset: 16, ^2))) ; guid = 6203814149063363976