Move hash code from hidden string to a private symbol

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 3282 matching lines @@
   return Max(capacity, kMinCapacity);
 }
 
 
 template <typename Derived, typename Shape, typename Key>
 int HashTable<Derived, Shape, Key>::FindEntry(Key key) {
   return FindEntry(GetIsolate(), key);
 }
 
 
+template<typename Derived, typename Shape, typename Key>
+int HashTable<Derived, Shape, Key>::FindEntry(Isolate* isolate, Key key) {
+  return FindEntry(isolate, key, HashTable::Hash(key));
+}
+
+
 // Find entry for key otherwise return kNotFound.
-template<typename Derived, typename Shape, typename Key>
-int HashTable<Derived, Shape, Key>::FindEntry(Isolate* isolate, Key key) {
+template <typename Derived, typename Shape, typename Key>
+int HashTable<Derived, Shape, Key>::FindEntry(Isolate* isolate, Key key,
+                                              int32_t hash) {
   uint32_t capacity = Capacity();
-  uint32_t entry = FirstProbe(HashTable::Hash(key), capacity);
+  uint32_t entry = FirstProbe(hash, capacity);
   uint32_t count = 1;
   // EnsureCapacity will guarantee the hash table is never full.
   while (true) {
     Object* element = KeyAt(entry);
     // Empty entry. Uses raw unchecked accessors because it is called by the
     // string table during bootstrapping.
     if (element == isolate->heap()->raw_unchecked_undefined_value()) break;
     if (element != isolate->heap()->raw_unchecked_the_hole_value() &&
         Shape::IsMatch(key, element)) return entry;
     entry = NextProbe(entry, count++, capacity);
@@ skipping 4316 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_