Changeset 37321 in webkit for trunk/JavaScriptCore/kjs

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):

Location:

trunk/JavaScriptCore/kjs

Files:

• PropertyMap.cpp (modified) (3 diffs)
• PropertyMap.h (modified) (1 diff)
• StructureID.cpp (modified) (3 diffs)
• StructureID.h (modified) (2 diffs)

trunk/JavaScriptCore/kjs/PropertyMap.cpp

@@ -115 +115 @@
 }
 
-void PropertyMap::put(const Identifier& propertyName, JSValue* value, unsigned attributes, bool checkReadOnly, JSObject* slotBase, PutPropertySlot& slot, PropertyStorage& propertyStorage)
+size_t PropertyMap::put(const Identifier& propertyName, JSValue* value, unsigned attributes, bool checkReadOnly, JSObject* slotBase, PutPropertySlot& slot, PropertyStorage& propertyStorage)
 {
     ASSERT(!propertyName.isNull());
@@ -145 +145 @@
         if (m_table->entries()[entryIndex - 1].key == rep) {
             if (checkReadOnly && (m_table->entries()[entryIndex - 1].attributes & ReadOnly))
-                return;
+                return WTF::notFound;
             // Put a new value in an existing hash table entry.
             propertyStorage[entryIndex - 2] = value;
             // Attributes are intentionally not updated.
             slot.setExistingProperty(slotBase, entryIndex - 2);
-            return;
+            return entryIndex - 2;
         } else if (entryIndex == deletedSentinelIndex) {
             // If we find a deleted-element sentinel, remember it for use later.
@@ -203 +203 @@
     checkConsistency(propertyStorage);
     slot.setNewProperty(slotBase, entryIndex - 2);
+    return entryIndex - 2;
 }
 

trunk/JavaScriptCore/kjs/PropertyMap.h

@@ -95 +95 @@
         bool isEmpty() { return !m_table; }
 
-        void put(const Identifier& propertyName, JSValue*, unsigned attributes, bool checkReadOnly, JSObject* slotBase, PutPropertySlot&, PropertyStorage&);
+        size_t put(const Identifier& propertyName, JSValue*, unsigned attributes, bool checkReadOnly, JSObject* slotBase, PutPropertySlot&, PropertyStorage&);
         void remove(const Identifier& propertyName, PropertyStorage&);
 

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());

trunk/JavaScriptCore/kjs/StructureID.h

@@ -116 +116 @@
         PropertyMap& propertyMap() { return m_propertyMap; }
 
+        void setCachedTransistionOffset(size_t offset) { m_cachedTransistionOffset = offset; }
+        size_t cachedTransistionOffset() const { return m_cachedTransistionOffset; }
+
         void getEnumerablePropertyNames(ExecState*, PropertyNameArray&, JSObject*);
         void clearEnumerationCache();
@@ -146 +149 @@
 
         PropertyMap m_propertyMap;
+
+        size_t m_cachedTransistionOffset;
     };