diff -ru protobuf/src/google/protobuf/compiler/cpp/cpp_message.cc protobuf2/src/google/protobuf/compiler/cpp/cpp_message.cc
--- protobuf/src/google/protobuf/compiler/cpp/cpp_message.cc    2018-05-25 08:49:22.423803658 -0700
+++ protobuf2/src/google/protobuf/compiler/cpp/cpp_message.cc   2018-05-25 08:51:00.622866069 -0700
@@ -994,7 +994,7 @@
   vars["new_final"] = " PROTOBUF_FINAL";
 
   printer->Print(vars,
-    "void Swap($classname$* other);\n"
+    "GOOGLE_ATTRIBUTE_NOINLINE void Swap($classname$* other);\n"
     "friend void swap($classname$& a, $classname$& b) {\n"
     "  a.Swap(&b);\n"
     "}\n"
@@ -2973,7 +2973,7 @@
     // ownership situation: swapping across arenas or between an arena and a
     // heap requires copying.
     printer->Print(
-        "void $classname$::Swap($classname$* other) {\n"
+        "GOOGLE_ATTRIBUTE_NOINLINE void $classname$::Swap($classname$* other) {\n"
         "  if (other == this) return;\n"
         "  if (GetArenaNoVirtual() == other->GetArenaNoVirtual()) {\n"
         "    InternalSwap(other);\n"