--- a/lib/LTO/ThinLTOCodeGenerator.cpp	Fri Feb 16 19:10:49 2018 +0900
+++ b/lib/LTO/ThinLTOCodeGenerator.cpp	Sat Feb 17 09:57:20 2018 +0900
@@ -76,13 +76,13 @@
   if (TempDir.empty())
     return;
   // User asked to save temps, let dump the bitcode file after import.
-  std::string SaveTempPath = (TempDir + llvm::utostr(count) + Suffix).str();
+  std::string SaveTempPath = (TempDir + llvm::Twine(count) + Suffix).str();
   std::error_code EC;
   raw_fd_ostream OS(SaveTempPath, EC, sys::fs::F_None);
   if (EC)
     report_fatal_error(Twine("Failed to open ") + SaveTempPath +
                        " to save optimized bitcode\n");
-  WriteBitcodeToFile(&TheModule, OS, /* ShouldPreserveUseListOrder */ true);
+  WriteBitcodeToFile(TheModule, OS, /* ShouldPreserveUseListOrder */ true);
 }
 
 static const GlobalValueSummary *
@@ -476,7 +476,7 @@
       raw_svector_ostream OS(OutputBuffer);
       ProfileSummaryInfo PSI(TheModule);
       auto Index = buildModuleSummaryIndex(TheModule, nullptr, &PSI);
-      WriteBitcodeToFile(&TheModule, OS, true, &Index);
+      WriteBitcodeToFile(TheModule, OS, true, &Index);
     }
     return make_unique<ObjectMemoryBuffer>(std::move(OutputBuffer));
   }
@@ -592,7 +592,7 @@
  */
 std::unique_ptr<ModuleSummaryIndex> ThinLTOCodeGenerator::linkCombinedIndex() {
   std::unique_ptr<ModuleSummaryIndex> CombinedIndex =
-      llvm::make_unique<ModuleSummaryIndex>();
+      llvm::make_unique<ModuleSummaryIndex>(/*IsPeformingAnalysis=*/false);
   uint64_t NextModuleId = 0;
   for (auto &ModuleBuffer : Modules) {
     if (Error Err = readModuleSummaryIndex(ModuleBuffer.getMemBuffer(),
@@ -607,6 +607,32 @@
   return CombinedIndex;
 }
 
+static void internalizeAndPromoteInIndex(
+    const StringMap<FunctionImporter::ExportSetTy> &ExportLists,
+    const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols,
+    ModuleSummaryIndex &Index) {
+  auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
+    const auto &ExportList = ExportLists.find(ModuleIdentifier);
+    return (ExportList != ExportLists.end() &&
+            ExportList->second.count(GUID)) ||
+           GUIDPreservedSymbols.count(GUID);
+  };
+
+  thinLTOInternalizeAndPromoteInIndex(Index, isExported);
+}
+
+static void computeDeadSymbolsInIndex(
+    ModuleSummaryIndex &Index,
+    const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols) {
+  // We have no symbols resolution available. And can't do any better now in the
+  // case where the prevailing symbol is in a native object. It can be refined
+  // with linker information in the future.
+  auto isPrevailing = [&](GlobalValue::GUID G) {
+    return PrevailingType::Unknown;
+  };
+  computeDeadSymbols(Index, GUIDPreservedSymbols, isPrevailing);
+}
+
 /**
  * Perform promotion and renaming of exported internal functions.
  * Index is updated to reflect linkage changes from weak resolution.
@@ -625,7 +651,7 @@
       PreservedSymbols, Triple(TheModule.getTargetTriple()));
 
   // Compute "dead" symbols, we don't want to import/export these!
-  computeDeadSymbols(Index, GUIDPreservedSymbols);
+  computeDeadSymbolsInIndex(Index, GUIDPreservedSymbols);
 
   // Generate import/export list
   StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
@@ -642,13 +668,7 @@
 
   // Promote the exported values in the index, so that they are promoted
   // in the module.
-  auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
-    const auto &ExportList = ExportLists.find(ModuleIdentifier);
-    return (ExportList != ExportLists.end() &&
-            ExportList->second.count(GUID)) ||
-           GUIDPreservedSymbols.count(GUID);
-  };
-  thinLTOInternalizeAndPromoteInIndex(Index, isExported);
+  internalizeAndPromoteInIndex(ExportLists, GUIDPreservedSymbols, Index);
 
   promoteModule(TheModule, Index);
 }
@@ -670,7 +690,7 @@
       PreservedSymbols, Triple(TheModule.getTargetTriple()));
 
   // Compute "dead" symbols, we don't want to import/export these!
-  computeDeadSymbols(Index, GUIDPreservedSymbols);
+  computeDeadSymbolsInIndex(Index, GUIDPreservedSymbols);
 
   // Generate import/export list
   StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
@@ -747,7 +767,7 @@
   Index.collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
 
   // Compute "dead" symbols, we don't want to import/export these!
-  computeDeadSymbols(Index, GUIDPreservedSymbols);
+  computeDeadSymbolsInIndex(Index, GUIDPreservedSymbols);
 
   // Generate import/export list
   StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
@@ -762,13 +782,7 @@
     return;
 
   // Internalization
-  auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
-    const auto &ExportList = ExportLists.find(ModuleIdentifier);
-    return (ExportList != ExportLists.end() &&
-            ExportList->second.count(GUID)) ||
-           GUIDPreservedSymbols.count(GUID);
-  };
-  thinLTOInternalizeAndPromoteInIndex(Index, isExported);
+  internalizeAndPromoteInIndex(ExportLists, GUIDPreservedSymbols, Index);
   thinLTOInternalizeModule(TheModule,
                            ModuleToDefinedGVSummaries[ModuleIdentifier]);
 }
@@ -899,7 +913,7 @@
       computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple);
 
   // Compute "dead" symbols, we don't want to import/export these!
-  computeDeadSymbols(*Index, GUIDPreservedSymbols);
+  computeDeadSymbolsInIndex(*Index, GUIDPreservedSymbols);
 
   // Collect the import/export lists for all modules from the call-graph in the
   // combined index.
@@ -918,17 +932,10 @@
   // impacts the caching.
   resolveWeakForLinkerInIndex(*Index, ResolvedODR);
 
-  auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
-    const auto &ExportList = ExportLists.find(ModuleIdentifier);
-    return (ExportList != ExportLists.end() &&
-            ExportList->second.count(GUID)) ||
-           GUIDPreservedSymbols.count(GUID);
-  };
-
   // Use global summary-based analysis to identify symbols that can be
   // internalized (because they aren't exported or preserved as per callback).
   // Changes are made in the index, consumed in the ThinLTO backends.
-  thinLTOInternalizeAndPromoteInIndex(*Index, isExported);
+  internalizeAndPromoteInIndex(ExportLists, GUIDPreservedSymbols, *Index);
 
   // Make sure that every module has an entry in the ExportLists and
   // ResolvedODR maps to enable threaded access to these maps below.