Changeset 37321 in webkit for trunk/JavaScriptCore/kjs/StructureID.cpp

Timestamp:

Oct 5, 2008, 5:58:42 PM (17 years ago)

Author:

[email protected]

Message:

2008-10-05 Sam Weinig <​[email protected]>

Reviewed by Maciej Stachowiak.

Avoid an extra lookup when transitioning to an existing StructureID
by caching the offset of property that caused the transition.

1% win on V8 suite. Wash on SunSpider.

• kjs/PropertyMap.cpp: (JSC::PropertyMap::put):
• kjs/PropertyMap.h:
• kjs/StructureID.cpp: (JSC::StructureID::StructureID): (JSC::StructureID::addPropertyTransition):
• kjs/StructureID.h: (JSC::StructureID::setCachedTransistionOffset): (JSC::StructureID::cachedTransistionOffset):

File:

• trunk/JavaScriptCore/kjs/StructureID.cpp (modified) (3 diffs)

trunk/JavaScriptCore/kjs/StructureID.cpp

@@ -45 +45 @@
     , m_nameInPrevious(0)
     , m_transitionCount(0)
+    , m_cachedTransistionOffset(WTF::notFound)
 {
     ASSERT(m_prototype);
@@ -117 +118 @@
             slotBase->allocatePropertyStorage(structureID->m_propertyMap.size(), existingTransition->m_propertyMap.size());
 
-        size_t offset = existingTransition->propertyMap().getOffset(propertyName);
+        size_t offset = existingTransition->cachedTransistionOffset();
         ASSERT(offset != WTF::notFound);
         propertyStorage[offset] = value;
@@ -139 +140 @@
     transition->m_propertyMap = structureID->m_propertyMap;
 
-    transition->m_propertyMap.put(propertyName, value, attributes, false, slotBase, slot, propertyStorage);
+    size_t offset = transition->m_propertyMap.put(propertyName, value, attributes, false, slotBase, slot, propertyStorage);
+    transition->setCachedTransistionOffset(offset);
 
     structureID->m_transitionTable.add(make_pair(propertyName.ustring().rep(), attributes), transition.get());