Index: lib/LTO/LTO.cpp
===================================================================
--- lib/LTO/LTO.cpp
+++ lib/LTO/LTO.cpp
@@ -56,6 +56,11 @@
     DumpThinCGSCCs("dump-thin-cg-sccs", cl::init(false), cl::Hidden,
                    cl::desc("Dump the SCCs in the ThinLTO index's callgraph"));
 
+/// Enable global value internalization in LTO.
+cl::opt<bool> EnableLTOInternalization(
+    "enable-lto-internalization", cl::init(true), cl::Hidden,
+    cl::desc("Enable global value internalization in LTO"));
+
 // Returns a unique hash for the Module considering the current list of
 // export/import and other global analysis results.
 // The hash is produced in \p Key.
@@ -337,7 +342,8 @@
     if (isExported(S->modulePath(), GUID)) {
       if (GlobalValue::isLocalLinkage(S->linkage()))
         S->setLinkage(GlobalValue::ExternalLinkage);
-    } else if (!GlobalValue::isLocalLinkage(S->linkage()))
+    } else if (EnableLTOInternalization &&
+               !GlobalValue::isLocalLinkage(S->linkage()))
       S->setLinkage(GlobalValue::InternalLinkage);
   }
 }
@@ -869,7 +875,7 @@
         continue;
       GV->setUnnamedAddr(R.second.UnnamedAddr ? GlobalValue::UnnamedAddr::Global
                                               : GlobalValue::UnnamedAddr::None);
-      if (R.second.Partition == 0)
+      if (EnableLTOInternalization && R.second.Partition == 0)
         GV->setLinkage(GlobalValue::InternalLinkage);
     }
 
Index: lib/LTO/LTOCodeGenerator.cpp
===================================================================
--- lib/LTO/LTOCodeGenerator.cpp
+++ lib/LTO/LTOCodeGenerator.cpp
@@ -70,6 +70,9 @@
 #endif
 }
 
+/// Enable global value internalization in LTO.
+extern cl::opt<bool> EnableLTOInternalization;
+
 namespace llvm {
 cl::opt<bool> LTODiscardValueNames(
     "lto-discard-value-names",
@@ -419,7 +422,7 @@
   // Preserve linkonce value on linker request
   preserveDiscardableGVs(*MergedModule, mustPreserveGV);
 
-  if (!ShouldInternalize)
+  if (!EnableLTOInternalization || !ShouldInternalize)
     return;
 
   if (ShouldRestoreGlobalsLinkage) {
@@ -450,7 +453,8 @@
 
 /// Restore original linkage for symbols that may have been internalized
 void LTOCodeGenerator::restoreLinkageForExternals() {
-  if (!ShouldInternalize || !ShouldRestoreGlobalsLinkage)
+  if (!EnableLTOInternalization || !ShouldInternalize ||
+      !ShouldRestoreGlobalsLinkage)
     return;
 
   assert(ScopeRestrictionsDone &&