Use the PushIfAbsent function for the JSON stringify stack.

Optimize ConvertToString.
Review URL: http://codereview.chromium.org/5614004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5943 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/array.js

@@ -159,25 +159,23 @@ function Join(array, length, separator, convert) {
 }
 
 
-function ConvertToString(e) {
-  if (e == null) return '';
-  else return ToString(e);
+function ConvertToString(x) {
+  if (IS_STRING(x)) return x;
+  if (IS_NUMBER(x)) return %_NumberToString(x);
+  if (IS_BOOLEAN(x)) return x ? 'true' : 'false';
+  return (IS_NULL_OR_UNDEFINED(x)) ? '' : %ToString(%DefaultString(x));
 }
 
 
 function ConvertToLocaleString(e) {
-  if (e == null) {
-    return '';
-  } else {
-    // e_obj's toLocaleString might be overwritten, check if it is a function.
-    // Call ToString if toLocaleString is not a function.
-    // See issue 877615.
-    var e_obj = ToObject(e);
-    if (IS_FUNCTION(e_obj.toLocaleString))
-      return ToString(e_obj.toLocaleString());
-    else
-      return ToString(e);
-  }
+  // e_obj's toLocaleString might be overwritten, check if it is a function.
+  // Call ConvertToString if toLocaleString is not a function.
+  // See issue 877615.
+  var e_obj = ToObject(e);
+  if (IS_FUNCTION(e_obj.toLocaleString))
+    return ToString(e_obj.toLocaleString());
+  else
+    return ConvertToString(e);
 }
 
 
@@ -365,14 +363,13 @@ function ArrayJoin(separator) {
   if (IS_UNDEFINED(separator)) {
     separator = ',';
   } else if (!IS_STRING(separator)) {
-    separator = ToString(separator);
+    separator = NonStringToString(separator);
   }
 
   var result = %_FastAsciiArrayJoin(this, separator);
   if (!IS_UNDEFINED(result)) return result;
 
-  var length = TO_UINT32(this.length);
-  return Join(this, length, separator, ConvertToString);
+  return Join(this, TO_UINT32(this.length), separator, ConvertToString);
 }
 
 

src/json.js

@@ -66,21 +66,10 @@ function JSONParse(text, reviver) {
   }
 }
 
-function StackContains(stack, val) {
-  var length = stack.length;
-  for (var i = 0; i < length; i++) {
-    if (stack[i] === val) {
-      return true;
-    }
-  }
-  return false;
-}
-
 function SerializeArray(value, replacer, stack, indent, gap) {
-  if (StackContains(stack, value)) {
+  if (!%PushIfAbsent(stack, value)) {
     throw MakeTypeError('circular_structure', []);
   }
-  stack.push(value);
   var stepback = indent;
   indent += gap;
   var partial = [];
@@ -108,10 +97,9 @@ function SerializeArray(value, replacer, stack, indent, gap) {
 }
 
 function SerializeObject(value, replacer, stack, indent, gap) {
-  if (StackContains(stack, value)) {
+  if (!%PushIfAbsent(stack, value)) {
     throw MakeTypeError('circular_structure', []);
   }
-  stack.push(value);
   var stepback = indent;
   indent += gap;
   var partial = [];
@@ -197,10 +185,9 @@ function JSONSerialize(key, holder, replacer, stack, indent, gap) {
 
 
 function BasicSerializeArray(value, stack, builder) {
-  if (StackContains(stack, value)) {
+  if (!%PushIfAbsent(stack, value)) {
     throw MakeTypeError('circular_structure', []);
   }
-  stack.push(value);
   builder.push("[");
   var len = value.length;
   for (var i = 0; i < len; i++) {
@@ -220,10 +207,9 @@ function BasicSerializeArray(value, stack, builder) {
 
 
 function BasicSerializeObject(value, stack, builder) {
-  if (StackContains(stack, value)) {
+  if (!%PushIfAbsent(stack, value)) {
     throw MakeTypeError('circular_structure', []);
   }
-  stack.push(value);
   builder.push("{");
   for (var p in value) {
     if (%HasLocalProperty(value, p)) {

src/runtime.cc

@@ -7671,13 +7671,13 @@ static MaybeObject* Runtime_AllocateInNewSpace(Arguments args) {
 }
 
 
-// Push an array unto an array of arrays if it is not already in the
+// Push an object unto an array of objects if it is not already in the
 // array.  Returns true if the element was pushed on the stack and
 // false otherwise.
 static MaybeObject* Runtime_PushIfAbsent(Arguments args) {
   ASSERT(args.length() == 2);
   CONVERT_CHECKED(JSArray, array, args[0]);
-  CONVERT_CHECKED(JSArray, element, args[1]);
+  CONVERT_CHECKED(JSObject, element, args[1]);
   RUNTIME_ASSERT(array->HasFastElements());
   int length = Smi::cast(array->length())->value();
   FixedArray* elements = FixedArray::cast(array->elements());