Get rid of ZoneScope completely.

src/json-parser.h

Index: src/json-parser.h
diff --git a/src/json-parser.h b/src/json-parser.h
index 1e7ebd8c9eb5f5656349d95de41483b9b2fec661..b7794dfe6c0f67a89c7c5b5c263c52c747871041 100644
--- a/src/json-parser.h
+++ b/src/json-parser.h
@@ -43,15 +43,33 @@ namespace internal {
 template <bool seq_ascii>
 class JsonParser BASE_EMBEDDED {
  public:
-  static Handle<Object> Parse(Handle<String> source, Zone* zone) {
-    return JsonParser().ParseJson(source, zone);
+  static Handle<Object> Parse(Handle<String> source) {
+    return JsonParser(source).ParseJson();
   }
 
   static const int kEndOfString = -1;
 
  private:
+  explicit JsonParser(Handle<String> source)
+      : source_(source),
+        source_length_(source->length()),
+        isolate_(source->map()->GetHeap()->isolate()),
+        factory_(isolate_->factory()),
+        zone_(isolate_),
+        object_constructor_(isolate_->native_context()->object_function(),
+                            isolate_),
+        position_(-1) {
+    FlattenString(source_);
+    pretenure_ = (source_length_ >= kPretenureTreshold) ? TENURED : NOT_TENURED;
+
+    // Optimized fast case where we only have ASCII characters.
+    if (seq_ascii) {
+      seq_source_ = Handle<SeqOneByteString>::cast(source_);
+    }
+  }
+
   // Parse a string containing a single JSON value.
-  Handle<Object> ParseJson(Handle<String> source, Zone* zone);
+  Handle<Object> ParseJson();
 
   inline void Advance() {
     position_++;
@@ -179,7 +197,6 @@ class JsonParser BASE_EMBEDDED {
   inline Isolate* isolate() { return isolate_; }
   inline Factory* factory() { return factory_; }
   inline Handle<JSFunction> object_constructor() { return object_constructor_; }
-  inline Zone* zone() const { return zone_; }
 
   static const int kInitialSpecialStringLength = 1024;
   static const int kPretenureTreshold = 100 * 1024;
@@ -193,32 +210,14 @@ class JsonParser BASE_EMBEDDED {
   PretenureFlag pretenure_;
   Isolate* isolate_;
   Factory* factory_;
+  Zone zone_;
   Handle<JSFunction> object_constructor_;
   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(), 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<SeqOneByteString>::cast(source_);
-  }
-
-  // Set initial position right before the string.
-  position_ = -1;
+Handle<Object> JsonParser<seq_ascii>::ParseJson() {
   // Advance to the first character (possibly EOS)
   AdvanceSkipWhitespace();
   Handle<Object> result = ParseJsonValue();
@@ -264,7 +263,7 @@ Handle<Object> JsonParser<seq_ascii>::ParseJson(Handle<String> source,
         break;
     }
 
-    MessageLocation location(factory->NewScript(source),
+    MessageLocation location(factory->NewScript(source_),
                              position_,
                              position_ + 1);
     Handle<Object> result = factory->NewSyntaxError(message, array);
@@ -323,8 +322,7 @@ Handle<Object> JsonParser<seq_ascii>::ParseJsonObject() {
   Handle<JSObject> json_object =
       factory()->NewJSObject(object_constructor(), pretenure_);
   Handle<Map> map(json_object->map());
-  ZoneScope zone_scope(zone());
-  ZoneList<Handle<Object> > properties(8, zone());
+  ZoneList<Handle<Object> > properties(8, &zone_);

[danno, 2013/06/26 13:06:58]

here an else where, does it make sense to wrap zone_ in a simple accessor
function zone()?

[Benedikt Meurer, 2013/06/26 13:34:39]

Done.

   ASSERT_EQ(c0_, '{');
 
   bool transitioning = true;
@@ -420,7 +418,7 @@ Handle<Object> JsonParser<seq_ascii>::ParseJsonObject() {
               value = factory()->NewHeapNumber(
                   Handle<Smi>::cast(value)->value());
             }
-            properties.Add(value, zone());
+            properties.Add(value, &zone_);
             map = target;
             continue;
           } else {
@@ -469,8 +467,7 @@ Handle<Object> JsonParser<seq_ascii>::ParseJsonObject() {
 template <bool seq_ascii>
 Handle<Object> JsonParser<seq_ascii>::ParseJsonArray() {
   HandleScope scope(isolate());
-  ZoneScope zone_scope(zone());
-  ZoneList<Handle<Object> > elements(4, zone());
+  ZoneList<Handle<Object> > elements(4, &zone_);
   ASSERT_EQ(c0_, '[');
 
   AdvanceSkipWhitespace();
@@ -478,7 +475,7 @@ Handle<Object> JsonParser<seq_ascii>::ParseJsonArray() {
     do {
       Handle<Object> element = ParseJsonValue();
       if (element.is_null()) return ReportUnexpectedCharacter();
-      elements.Add(element, zone());
+      elements.Add(element, &zone_);
     } while (MatchSkipWhiteSpace(','));
     if (c0_ != ']') {
       return ReportUnexpectedCharacter();