Changeset 148036 in webkit

Timestamp:

Apr 9, 2013 12:16:18 PM (11 years ago)

Author:

mhahnenberg@apple.com

Message:

JSObject::getOwnNonIndexPropertyNames calculates numCacheableSlots incorrectly
​https://bugs.webkit.org/show_bug.cgi?id=114235

Reviewed by Geoffrey Garen.

Due to the way that numCacheableSlots is currently calculated, checking an object's prototype for enumerable
properties causes us not to cache any properties at all. We should only cache properties on the object itself
since we currently don't take advantage of any sort of name caching for properties in the prototype chain.
This fix undoes a ~2% SunSpider regression caused by ​http://trac.webkit.org/changeset/147570.

• runtime/JSObject.cpp:

(JSC::JSObject::getOwnNonIndexPropertyNames):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• runtime/JSObject.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2013-04-08  Mark Hahnenberg  <mhahnenberg@apple.com>
+
+        JSObject::getOwnNonIndexPropertyNames calculates numCacheableSlots incorrectly
+        https://bugs.webkit.org/show_bug.cgi?id=114235
+
+        Reviewed by Geoffrey Garen.
+
+        Due to the way that numCacheableSlots is currently calculated, checking an object's prototype for enumerable 
+        properties causes us not to cache any properties at all. We should only cache properties on the object itself
+        since we currently don't take advantage of any sort of name caching for properties in the prototype chain.
+        This fix undoes a ~2% SunSpider regression caused by http://trac.webkit.org/changeset/147570.
+
+        * runtime/JSObject.cpp:
+        (JSC::JSObject::getOwnNonIndexPropertyNames):
+
 2013-04-09  Ryosuke Niwa  <rniwa@webkit.org>
 

trunk/Source/JavaScriptCore/runtime/JSObject.cpp

@@ -1533 +1533 @@
 {
     getClassPropertyNames(exec, object->classInfo(), propertyNames, mode, object->staticFunctionsReified());
-    size_t preStructurePropertyNamesCount = propertyNames.size();
+
+    bool canCachePropertiesFromStructure = !propertyNames.size();
     object->structure()->getPropertyNamesFromStructure(exec->globalData(), propertyNames, mode);
-    size_t numCacheableSlots = preStructurePropertyNamesCount ? 0 : propertyNames.size();
-    propertyNames.setNumCacheableSlots(numCacheableSlots);
+
+    if (canCachePropertiesFromStructure)
+        propertyNames.setNumCacheableSlots(propertyNames.size());
 }