Improve handle allocation in JSON.parse.

src/json-parser.h

 // Copyright 2011 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 158 matching lines @@
   uc32 c0_;
   int position_;
   Zone* zone_;
 };
 
 template <bool seq_ascii>
 Handle<Object> JsonParser<seq_ascii>::ParseJson(Handle<String> source,
                                                 Zone* zone) {
   isolate_ = source->map()->GetHeap()->isolate();
   factory_ = isolate_->factory();
-  object_constructor_ =
-      Handle<JSFunction>(isolate()->native_context()->object_function());
+  object_constructor_ = Handle<JSFunction>(
+      isolate()->native_context()->object_function(), isolate());
   zone_ = zone;
   FlattenString(source);
   source_ = source;
   source_length_ = source_->length();
   pretenure_ = (source_length_ >= kPretenureTreshold) ? TENURED : NOT_TENURED;
 
   // Optimized fast case where we only have ASCII characters.
   if (seq_ascii) {
     seq_source_ = Handle<SeqAsciiString>::cast(source_);
   }
@@ skipping 413 matching lines @@
 }
 
 
 template <bool seq_ascii>
 template <bool is_symbol>
 Handle<String> JsonParser<seq_ascii>::ScanJsonString() {
   ASSERT_EQ('"', c0_);
   Advance();
   if (c0_ == '"') {
     AdvanceSkipWhitespace();
-    return Handle<String>(isolate()->heap()->empty_string());
+    return isolate()->factory()->empty_string();

[Toon Verwaest, 2012/11/05 10:14:47]

You can directly use factory() without isolate()->

   }
 
   if (seq_ascii && is_symbol) {
     // Fast path for existing symbols.  If the the string being parsed is not
     // a known symbol, contains backslashes or unexpectedly reaches the end of
     // string, return with an empty handle.
     uint32_t running_hash = isolate()->heap()->HashSeed();
     int position = position_;
     uc32 c0 = c0_;
     do {
@@ skipping 25 matching lines @@
       if (element == isolate()->heap()->undefined_value()) {
         // Lookup failure.
         break;
       }
       if (element != isolate()->heap()->the_hole_value() &&
           String::cast(element)->IsAsciiEqualTo(string_vector)) {
         // Lookup success, update the current position.
         position_ = position;
         // Advance past the last '"'.
         AdvanceSkipWhitespace();
-        return Handle<String>(String::cast(element));
+        return Handle<String>(String::cast(element), isolate());
       }
       entry = SymbolTable::NextProbe(entry, count++, capacity);
     }
   }
 
   int beg_pos = position_;
   // Fast case for ASCII only without escape characters.
   do {
     // Check for control character (0x00-0x1f) or unterminated string (<0).
     if (c0_ < 0x20) return Handle<String>::null();
@@ skipping 24 matching lines @@
   }
   ASSERT_EQ('"', c0_);
   // Advance past the last '"'.
   AdvanceSkipWhitespace();
   return result;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_JSON_PARSER_H_