Index: include/llvm/LTO/LTO.h
===================================================================
--- include/llvm/LTO/LTO.h
+++ include/llvm/LTO/LTO.h
@@ -60,7 +60,6 @@
     ModuleSummaryIndex &Index,
     function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
         isPrevailing,
-    function_ref<bool(StringRef, GlobalValue::GUID)> isExported,
     function_ref<void(StringRef, GlobalValue::GUID, GlobalValue::LinkageTypes)>
         recordNewLinkage);
 
Index: lib/LTO/LTO.cpp
===================================================================
--- lib/LTO/LTO.cpp
+++ lib/LTO/LTO.cpp
@@ -45,26 +45,17 @@
     DenseSet<GlobalValueSummary *> &GlobalInvolvedWithAlias,
     function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
         isPrevailing,
-    function_ref<bool(StringRef, GlobalValue::GUID)> isExported,
     function_ref<void(StringRef, GlobalValue::GUID, GlobalValue::LinkageTypes)>
         recordNewLinkage) {
-  auto HasMultipleCopies = GVSummaryList.size() > 1;
-
   for (auto &S : GVSummaryList) {
     if (GlobalInvolvedWithAlias.count(S.get()))
       continue;
     GlobalValue::LinkageTypes OriginalLinkage = S->linkage();
     if (!GlobalValue::isWeakForLinker(OriginalLinkage))
       continue;
-    // We need to emit only one of these, the first module will keep it,
+    // We need to emit only one of these. The prevailing module will keep it,
     // but turned into a weak, while the others will drop it when possible.
-    if (!HasMultipleCopies) {
-      // Exported Linkonce needs to be promoted to not be discarded.
-      if (GlobalValue::isLinkOnceLinkage(OriginalLinkage) &&
-          isExported(S->modulePath(), GUID))
-        S->setLinkage(GlobalValue::getWeakLinkage(
-            GlobalValue::isLinkOnceODRLinkage(OriginalLinkage)));
-    } else if (isPrevailing(GUID, S.get())) {
+    if (isPrevailing(GUID, S.get())) {
       if (GlobalValue::isLinkOnceLinkage(OriginalLinkage))
         S->setLinkage(GlobalValue::getWeakLinkage(
             GlobalValue::isLinkOnceODRLinkage(OriginalLinkage)));
@@ -89,7 +80,6 @@
     ModuleSummaryIndex &Index,
     function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
         isPrevailing,
-    function_ref<bool(StringRef, GlobalValue::GUID)> isExported,
     function_ref<void(StringRef, GlobalValue::GUID, GlobalValue::LinkageTypes)>
         recordNewLinkage) {
   if (Index.modulePaths().size() == 1)
@@ -107,7 +97,7 @@
 
   for (auto &I : Index)
     thinLTOResolveWeakForLinkerGUID(I.second, I.first, GlobalInvolvedWithAlias,
-                                    isPrevailing, isExported, recordNewLinkage);
+                                    isPrevailing, recordNewLinkage);
 }
 
 static void thinLTOInternalizeAndPromoteGUID(
Index: lib/LTO/ThinLTOCodeGenerator.cpp
===================================================================
--- lib/LTO/ThinLTOCodeGenerator.cpp
+++ lib/LTO/ThinLTOCodeGenerator.cpp
@@ -393,8 +393,6 @@
 /// copies when possible).
 static void resolveWeakForLinkerInIndex(
     ModuleSummaryIndex &Index,
-    const StringMap<FunctionImporter::ExportSetTy> &ExportLists,
-    const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols,
     StringMap<std::map<GlobalValue::GUID, GlobalValue::LinkageTypes>>
         &ResolvedODR) {
 
@@ -409,21 +407,13 @@
     return Prevailing->second == S;
   };
 
-  auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
-    const auto &ExportList = ExportLists.find(ModuleIdentifier);
-    return (ExportList != ExportLists.end() &&
-            ExportList->second.count(GUID)) ||
-           GUIDPreservedSymbols.count(GUID);
-  };
-
   auto recordNewLinkage = [&](StringRef ModuleIdentifier,
                               GlobalValue::GUID GUID,
                               GlobalValue::LinkageTypes NewLinkage) {
     ResolvedODR[ModuleIdentifier][GUID] = NewLinkage;
   };
 
-  thinLTOResolveWeakForLinkerInIndex(Index, isPrevailing, isExported,
-                                     recordNewLinkage);
+  thinLTOResolveWeakForLinkerInIndex(Index, isPrevailing, recordNewLinkage);
 }
 
 // Initialize the TargetMachine builder for a given Triple
@@ -537,14 +527,9 @@
   ComputeCrossModuleImport(Index, ModuleToDefinedGVSummaries, ImportLists,
                            ExportLists);
 
-  // Convert the preserved symbols set from string to GUID
-  auto GUIDPreservedSymbols =
-  computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple);
-
   // Resolve LinkOnce/Weak symbols.
   StringMap<std::map<GlobalValue::GUID, GlobalValue::LinkageTypes>> ResolvedODR;
-  resolveWeakForLinkerInIndex(Index, ExportLists, GUIDPreservedSymbols,
-                              ResolvedODR);
+  resolveWeakForLinkerInIndex(Index, ResolvedODR);
 
   thinLTOResolveWeakForLinkerModule(
       TheModule, ModuleToDefinedGVSummaries[ModuleIdentifier]);
@@ -750,8 +735,7 @@
 
   // Resolve LinkOnce/Weak symbols, this has to be computed early because it
   // impacts the caching.
-  resolveWeakForLinkerInIndex(*Index, ExportLists, GUIDPreservedSymbols,
-                              ResolvedODR);
+  resolveWeakForLinkerInIndex(*Index, ResolvedODR);
 
   auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
     const auto &ExportList = ExportLists.find(ModuleIdentifier);
Index: test/ThinLTO/X86/alias_import.ll
===================================================================
--- test/ThinLTO/X86/alias_import.ll
+++ test/ThinLTO/X86/alias_import.ll
@@ -10,36 +10,36 @@
 ; available_externally, i.e linkOnceODR. (FIXME this limitation could be lifted)
 ; PROMOTE-DAG: @globalfuncAlias = alias void (...), bitcast (void ()* @globalfunc to void (...)*)
 ; PROMOTE-DAG: @globalfuncWeakAlias = weak alias void (...), bitcast (void ()* @globalfunc to void (...)*)
-; PROMOTE-DAG: @globalfuncLinkonceAlias = linkonce alias void (...), bitcast (void ()* @globalfunc to void (...)*)
+; PROMOTE-DAG: @globalfuncLinkonceAlias = weak alias void (...), bitcast (void ()* @globalfunc to void (...)*)
 ; PROMOTE-DAG: @globalfuncWeakODRAlias = weak_odr alias void (...), bitcast (void ()* @globalfunc to void (...)*)
-; PROMOTE-DAG: @globalfuncLinkonceODRAlias = linkonce_odr alias void (...), bitcast (void ()* @globalfunc to void (...)*)
+; PROMOTE-DAG: @globalfuncLinkonceODRAlias = weak_odr alias void (...), bitcast (void ()* @globalfunc to void (...)*)
 ; PROMOTE-DAG: @internalfuncAlias = alias void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
 ; PROMOTE-DAG: @internalfuncWeakAlias = weak alias void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
-; PROMOTE-DAG: @internalfuncLinkonceAlias = linkonce alias void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
+; PROMOTE-DAG: @internalfuncLinkonceAlias = weak alias void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
 ; PROMOTE-DAG: @internalfuncWeakODRAlias = weak_odr alias void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
-; PROMOTE-DAG: @internalfuncLinkonceODRAlias = linkonce_odr alias void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
+; PROMOTE-DAG: @internalfuncLinkonceODRAlias = weak_odr alias void (...), bitcast (void ()* @internalfunc.llvm.0 to void (...)*)
 ; PROMOTE-DAG: @linkoncefuncAlias = alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
 ; PROMOTE-DAG: @linkoncefuncWeakAlias = weak alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
-; PROMOTE-DAG: @linkoncefuncLinkonceAlias = linkonce alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
+; PROMOTE-DAG: @linkoncefuncLinkonceAlias = weak alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
 ; PROMOTE-DAG: @linkoncefuncWeakODRAlias = weak_odr alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
-; PROMOTE-DAG: @linkoncefuncLinkonceODRAlias = linkonce_odr alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
+; PROMOTE-DAG: @linkoncefuncLinkonceODRAlias = weak_odr alias void (...), bitcast (void ()* @linkoncefunc to void (...)*)
 ; PROMOTE-DAG: @weakfuncAlias = alias void (...), bitcast (void ()* @weakfunc to void (...)*)
 ; PROMOTE-DAG: @weakfuncWeakAlias = weak alias void (...), bitcast (void ()* @weakfunc to void (...)*)
-; PROMOTE-DAG: @weakfuncLinkonceAlias = linkonce alias void (...), bitcast (void ()* @weakfunc to void (...)*)
+; PROMOTE-DAG: @weakfuncLinkonceAlias = weak alias void (...), bitcast (void ()* @weakfunc to void (...)*)
 ; PROMOTE-DAG: @weakfuncWeakODRAlias = weak_odr alias void (...), bitcast (void ()* @weakfunc to void (...)*)
-; PROMOTE-DAG: @weakfuncLinkonceODRAlias = linkonce_odr alias void (...), bitcast (void ()* @weakfunc to void (...)*)
+; PROMOTE-DAG: @weakfuncLinkonceODRAlias = weak_odr alias void (...), bitcast (void ()* @weakfunc to void (...)*)
 ; PROMOTE-DAG: @weakODRfuncAlias = alias void (...), bitcast (void ()* @weakODRfunc to void (...)*)
 ; PROMOTE-DAG: @weakODRfuncWeakAlias = weak alias void (...), bitcast (void ()* @weakODRfunc to void (...)*)
-; PROMOTE-DAG: @weakODRfuncLinkonceAlias = linkonce alias void (...), bitcast (void ()* @weakODRfunc to void (...)*)
+; PROMOTE-DAG: @weakODRfuncLinkonceAlias = weak alias void (...), bitcast (void ()* @weakODRfunc to void (...)*)
 ; PROMOTE-DAG: @weakODRfuncWeakODRAlias = weak_odr alias void (...), bitcast (void ()* @weakODRfunc to void (...)*)
-; PROMOTE-DAG: @weakODRfuncLinkonceODRAlias = linkonce_odr alias void (...), bitcast (void ()* @weakODRfunc to void (...)*)
+; PROMOTE-DAG: @weakODRfuncLinkonceODRAlias = weak_odr alias void (...), bitcast (void ()* @weakODRfunc to void (...)*)
 
 ; Only alias to LinkonceODR aliasee can be imported
 ; PROMOTE-DAG: @linkonceODRfuncAlias = alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
 ; PROMOTE-DAG: @linkonceODRfuncWeakAlias = weak alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
 ; PROMOTE-DAG: @linkonceODRfuncWeakODRAlias = weak_odr alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
 ; Amongst these that are imported, check that we promote only linkonce->weak
-; PROMOTE-DAG: @linkonceODRfuncLinkonceAlias = linkonce alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
+; PROMOTE-DAG: @linkonceODRfuncLinkonceAlias = weak alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
 ; PROMOTE-DAG: @linkonceODRfuncLinkonceODRAlias = weak_odr alias void (...), bitcast (void ()* @linkonceODRfunc to void (...)*)
 
 ; These will be imported, check the linkage/renaming after promotion
Index: test/ThinLTO/X86/weak_resolution.ll
===================================================================
--- test/ThinLTO/X86/weak_resolution.ll
+++ test/ThinLTO/X86/weak_resolution.ll
@@ -65,7 +65,7 @@
   ret void
 }
 
-; MOD1: define linkonce_odr void @linkonceodrfuncInSingleModule()
+; MOD1: define weak_odr void @linkonceodrfuncInSingleModule()
 ; EXPORTED: define weak_odr void @linkonceodrfuncInSingleModule()
 define linkonce_odr void @linkonceodrfuncInSingleModule() #0 {
 entry: