gistfile1.txt

diff --git a/Source/JavaScriptCore/runtime/ArrayPrototype.cpp b/Source/JavaScriptCore/runtime/ArrayPrototype.cpp
index 818895c..4b1278a 100644
--- a/Source/JavaScriptCore/runtime/ArrayPrototype.cpp
+++ b/Source/JavaScriptCore/runtime/ArrayPrototype.cpp
@@ -383,7 +383,7 @@ EncodedJSValue JSC_HOST_CALL arrayProtoFuncJoin(ExecState* exec)
 
     UString separator;
     if (!exec->argument(0).isUndefined())
-        separator = exec->argument(0).toString(exec)->value(exec);
+        separator = fastJSValuetoUString(exec->argument(0), exec);
     if (separator.isNull())
         separator = UString(",");
 
@@ -399,7 +399,7 @@ EncodedJSValue JSC_HOST_CALL arrayProtoFuncJoin(ExecState* exec)
 
             JSValue element = array->getIndex(k);
             if (!element.isUndefinedOrNull())
-                stringJoiner.append(element.toString(exec)->value(exec));
+                stringJoiner.append(fastJSValuetoUString(element, exec));
             else
                 stringJoiner.append(UString());
         }
@@ -408,7 +408,7 @@ EncodedJSValue JSC_HOST_CALL arrayProtoFuncJoin(ExecState* exec)
     for (; k < length; k++) {
         JSValue element = thisObj->get(exec, k);
         if (!element.isUndefinedOrNull())
-            stringJoiner.append(element.toString(exec)->value(exec));
+            stringJoiner.append(fastJSValuetoUString(element, exec));
         else
             stringJoiner.append(UString());
     }
diff --git a/Source/JavaScriptCore/runtime/JSString.h b/Source/JavaScriptCore/runtime/JSString.h
index 32a3278..7c21397 100644
--- a/Source/JavaScriptCore/runtime/JSString.h
+++ b/Source/JavaScriptCore/runtime/JSString.h
@@ -462,6 +462,35 @@ namespace JSC {
         return toStringSlowCase(exec);
     }
 
+    inline UString JSValue::toUString(ExecState* exec) const
+    {
+        if (isString())
+            return static_cast<JSString*>(asCell())->value(exec);
+        return toUStringSlowCase(exec);
+    }
+
+    ALWAYS_INLINE UString fastJSValueNotStringtoUString(const JSValue& value, ExecState* exec)
+    {
+        JSGlobalData& globalData = exec->globalData();
+        if (value.isInt32())
+            return globalData.numericStrings.add(value.asInt32());
+        if (value.isDouble())
+            return globalData.numericStrings.add(value.asDouble());
+        if (value.isTrue())
+            return globalData.propertyNames->trueKeyword.ustring();
+        if (value.isFalse())
+            return globalData.propertyNames->falseKeyword.ustring();
+        return value.toString(exec)->value(exec);
+    }
+
+    ALWAYS_INLINE UString fastJSValuetoUString(const JSValue& value, ExecState* exec)
+    {
+        if (value.isString())
+            return static_cast<JSString*>(value.asCell())->value(exec);
+
+        return fastJSValueNotStringtoUString(value, exec);
+    }
+
 } // namespace JSC
 
 #endif // JSString_h
diff --git a/Source/JavaScriptCore/runtime/JSValue.cpp b/Source/JavaScriptCore/runtime/JSValue.cpp
index 7bb895a..fa83c6e 100644
--- a/Source/JavaScriptCore/runtime/JSValue.cpp
+++ b/Source/JavaScriptCore/runtime/JSValue.cpp
@@ -283,4 +283,9 @@ JSString* JSValue::toStringSlowCase(ExecState* exec) const
     return value.toString(exec);
 }
 
+UString JSValue::toUStringSlowCase(ExecState* exec) const
+{
+    return fastJSValueNotStringtoUString(*this, exec);
+}
+
 } // namespace JSC
diff --git a/Source/JavaScriptCore/runtime/JSValue.h b/Source/JavaScriptCore/runtime/JSValue.h
index ba0ae23..006e894 100644
--- a/Source/JavaScriptCore/runtime/JSValue.h
+++ b/Source/JavaScriptCore/runtime/JSValue.h
@@ -203,6 +203,7 @@ namespace JSC {
         // been set in the ExecState already.
         double toNumber(ExecState*) const;
         JSString* toString(ExecState*) const;
+        UString toUString(ExecState*) const;
         JSObject* toObject(ExecState*) const;
         JSObject* toObject(ExecState*, JSGlobalObject*) const;
 
@@ -251,6 +252,7 @@ namespace JSC {
         inline const JSValue asValue() const { return *this; }
         JS_EXPORT_PRIVATE double toNumberSlowCase(ExecState*) const;
         JS_EXPORT_PRIVATE JSString* toStringSlowCase(ExecState*) const;
+        JS_EXPORT_PRIVATE UString toUStringSlowCase(ExecState*) const;
         JS_EXPORT_PRIVATE JSObject* toObjectSlowCase(ExecState*, JSGlobalObject*) const;
         JS_EXPORT_PRIVATE JSObject* toThisObjectSlowCase(ExecState*) const;
 
@@ -389,6 +391,9 @@ namespace JSC {
     };
 #endif
 
+    // Inline conversion to UString for use only in tight loop.
+    UString fastJSValuetoUString(const JSValue&, ExecState*);
+
     typedef HashMap<EncodedJSValue, unsigned, EncodedJSValueHash, EncodedJSValueHashTraits> JSValueMap;
 
     // Stand-alone helper functions.