Use hash map to look for objects in the root array when serializing.

src/isolate.cc

 // 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.
 
 #include <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 
 #include "src/v8.h"
 
@@ skipping 2192 matching lines @@
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);
 ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
 ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
 #undef ISOLATE_FIELD_OFFSET
 #endif
 
 
 Handle<JSObject> Isolate::GetSymbolRegistry() {
-  if (heap()->symbol_registry()->IsUndefined()) {
+  if (heap()->symbol_registry()->IsSmi()) {
     Handle<Map> map = factory()->NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
     Handle<JSObject> registry = factory()->NewJSObjectFromMap(map);
     heap()->set_symbol_registry(*registry);
 
     static const char* nested[] = {
       "for", "for_api", "for_intern", "keyFor", "private_api", "private_intern"
     };
     for (unsigned i = 0; i < arraysize(nested); ++i) {
       Handle<String> name = factory()->InternalizeUtf8String(nested[i]);
       Handle<JSObject> obj = factory()->NewJSObjectFromMap(map);
@@ skipping 179 matching lines @@
   if (prev_ && prev_->Intercept(flag)) return true;
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 } }  // namespace v8::internal