Reland "Allocation site support for monomorphic StringAdds in BinaryOps".

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1331 matching lines @@
       IsMoreGeneralElementsKindTransition(from, to)) {
     return TRACK_ALLOCATION_SITE;
   }
 
   return DONT_TRACK_ALLOCATION_SITE;
 }
 
 
 inline bool AllocationSite::CanTrack(InstanceType type) {
   if (FLAG_allocation_site_pretenuring) {
-    return type == JS_ARRAY_TYPE || type == JS_OBJECT_TYPE;
+    return type == JS_ARRAY_TYPE ||
+        type == JS_OBJECT_TYPE ||
+        type < FIRST_NONSTRING_TYPE;
   }
   return type == JS_ARRAY_TYPE;
 }
 
 
 inline DependentCode::DependencyGroup AllocationSite::ToDependencyGroup(
     Reason reason) {
   switch (reason) {
     case TENURING:
       return DependentCode::kAllocationSiteTenuringChangedGroup;
@@ skipping 5115 matching lines @@
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_