Changeset 37370 in webkit for trunk/JavaScriptCore/kjs/JSObject.h

Timestamp:

Oct 6, 2008, 10:43:06 PM (17 years ago)

Author:

[email protected]

Message:

2008-10-06 Sam Weinig <​[email protected]>

Reviewed by Cameron Zwarich.

Fix for ​https://bugs.webkit.org/show_bug.cgi?id=21415
Improve the division between PropertyStorageArray and PropertyMap

• Rework ProperyMap to store offsets in the value so that they don't change when rehashing. This allows us not to have to keep the PropertyStorageArray in sync and thus not have to pass it in.
• Rename PropertyMap::getOffset -> PropertyMap::get since put/remove now also return offsets.
• A Vector of deleted offsets is now needed since the storage is out of band.

1% win on SunSpider. Wash on V8 suite.

• JavaScriptCore.exp:
• VM/CTI.cpp: (JSC::transitionWillNeedStorageRealloc):
• VM/Machine.cpp: (JSC::Machine::privateExecute): Transition logic can be greatly simplified by the fact that the storage capacity is always known, and is correct for the inline case.
• kjs/JSObject.cpp: (JSC::JSObject::put): Rename getOffset -> get. (JSC::JSObject::deleteProperty): Ditto. (JSC::JSObject::getPropertyAttributes): Ditto. (JSC::JSObject::removeDirect): Use returned offset to clear the value in the PropertyNameArray. (JSC::JSObject::allocatePropertyStorage): Add assert.
• kjs/JSObject.h: (JSC::JSObject::getDirect): Rename getOffset -> get (JSC::JSObject::getDirectLocation): Rename getOffset -> get (JSC::JSObject::putDirect): Use propertyStorageCapacity to determine whether or not to resize. Also, since put now returns an offset (and thus addPropertyTransition does also) setting of the PropertyStorageArray is now done here. (JSC::JSObject::transitionTo):
• kjs/PropertyMap.cpp: (JSC::PropertyMap::checkConsistency): PropertyStorageArray is no longer passed in. (JSC::PropertyMap::operator=): Copy the delete offsets vector. (JSC::PropertyMap::put): Instead of setting the PropertyNameArray explicitly, return the offset where the value should go. (JSC::PropertyMap::remove): Instead of removing from the PropertyNameArray explicitly, return the offset where the value should be removed. (JSC::PropertyMap::get): Switch to using the stored offset, instead of the implicit one. (JSC::PropertyMap::insert): (JSC::PropertyMap::expand): This is never called when m_table is null, so remove that branch and add it as an assertion. (JSC::PropertyMap::createTable): Consistency checks no longer take a PropertyNameArray. (JSC::PropertyMap::rehash): No need to rehash the PropertyNameArray now that it is completely out of band.
• kjs/PropertyMap.h: (JSC::PropertyMapEntry::PropertyMapEntry): Store offset into PropertyNameArray. (JSC::PropertyMap::get): Switch to using the stored offset, instead of the implicit one.
• kjs/StructureID.cpp: (JSC::StructureID::StructureID): Initialize the propertyStorageCapacity to JSObject::inlineStorageCapacity. (JSC::StructureID::growPropertyStorageCapacity): Grow the storage capacity as described below. (JSC::StructureID::addPropertyTransition): Copy the storage capacity. (JSC::StructureID::toDictionaryTransition): Ditto. (JSC::StructureID::changePrototypeTransition): Ditto. (JSC::StructureID::getterSetterTransition): Ditto.
• kjs/StructureID.h: (JSC::StructureID::propertyStorageCapacity): Add propertyStorageCapacity which is the current capacity for the JSObjects PropertyStorageArray. It starts at the JSObject::inlineStorageCapacity (currently 2), then when it first needs to be resized moves to the JSObject::nonInlineBaseStorageCapacity (currently 16), and after that doubles each time.

File:

• trunk/JavaScriptCore/kjs/JSObject.h (modified) (6 diffs)

trunk/JavaScriptCore/kjs/JSObject.h

@@ -123 +123 @@
         JSValue* getDirect(const Identifier& propertyName) const
         {
-            size_t offset = m_structureID->propertyMap().getOffset(propertyName);
+            size_t offset = m_structureID->propertyMap().get(propertyName);
             return offset != WTF::notFound ? m_propertyStorage[offset] : 0;
         }
@@ -129 +129 @@
         JSValue** getDirectLocation(const Identifier& propertyName)
         {
-            size_t offset = m_structureID->propertyMap().getOffset(propertyName);
+            size_t offset = m_structureID->propertyMap().get(propertyName);
             return offset != WTF::notFound ? locationForOffset(offset) : 0;
         }
@@ -135 +135 @@
         JSValue** getDirectLocation(const Identifier& propertyName, unsigned& attributes)
         {
-            size_t offset = m_structureID->propertyMap().getOffset(propertyName, attributes);
+            size_t offset = m_structureID->propertyMap().get(propertyName, attributes);
             return offset != WTF::notFound ? locationForOffset(offset) : 0;
         }
@@ -179 +179 @@
 
         static const size_t inlineStorageCapacity = 2;
+        static const size_t nonInlineBaseStorageCapacity = 16;
 
         static PassRefPtr<StructureID> createStructureID(JSValue* proto) { return StructureID::create(proto, TypeInfo(ObjectType)); }
@@ -365 +366 @@
     ASSERT(!Heap::heap(value) || Heap::heap(value) == Heap::heap(this));
 
-     if (m_structureID->isDictionary()) {
-         unsigned currentAttributes;
-         size_t offset = m_structureID->propertyMap().getOffset(propertyName, currentAttributes);
-         if (offset != WTF::notFound) {
-             if (checkReadOnly && currentAttributes & ReadOnly)
-                 return;
-             m_propertyStorage[offset] = value;
-             slot.setExistingProperty(this, offset);
-             return;
-         }
-
-         if (m_structureID->propertyMap().storageSize() == inlineStorageCapacity)
-             allocatePropertyStorage(m_structureID->propertyMap().storageSize(), m_structureID->propertyMap().size());
-         m_structureID->propertyMap().put(propertyName, value, attributes, checkReadOnly, this, slot, m_propertyStorage);
-         m_structureID->clearEnumerationCache();
-         return;
-     }
+    if (m_structureID->isDictionary()) {
+        unsigned currentAttributes;
+        size_t offset = m_structureID->propertyMap().get(propertyName, currentAttributes);
+        if (offset != WTF::notFound) {
+            if (checkReadOnly && currentAttributes & ReadOnly)
+                return;
+            m_propertyStorage[offset] = value;
+            slot.setExistingProperty(this, offset);
+            return;
+        }
+
+        size_t currentCapacity = m_structureID->propertyStorageCapacity();
+        offset = m_structureID->propertyMap().put(propertyName, attributes);
+        if (m_structureID->propertyMap().storageSize() > m_structureID->propertyStorageCapacity()) {
+            m_structureID->growPropertyStorageCapacity();
+            allocatePropertyStorage(currentCapacity, m_structureID->propertyStorageCapacity());
+        }
+
+        m_propertyStorage[offset] = value;
+        slot.setNewProperty(this, offset);
+        m_structureID->clearEnumerationCache();
+        return;
+    }
 
     unsigned currentAttributes;
-    size_t offset = m_structureID->propertyMap().getOffset(propertyName, currentAttributes);
+    size_t offset = m_structureID->propertyMap().get(propertyName, currentAttributes);
     if (offset != WTF::notFound) {
         if (checkReadOnly && currentAttributes & ReadOnly)
@@ -393 +400 @@
     }
 
-     if (m_structureID->propertyMap().storageSize() == inlineStorageCapacity)
-         allocatePropertyStorage(m_structureID->propertyMap().storageSize(), m_structureID->propertyMap().size());
-
-     RefPtr<StructureID> structureID = StructureID::addPropertyTransition(m_structureID, propertyName, value, attributes, this, slot, m_propertyStorage);
-     slot.setWasTransition(true);
-     setStructureID(structureID.release());
+    size_t currentCapacity = m_structureID->propertyStorageCapacity();
+    RefPtr<StructureID> structureID = StructureID::addPropertyTransition(m_structureID, propertyName, attributes, offset);
+    if (currentCapacity != structureID->propertyStorageCapacity())
+        allocatePropertyStorage(currentCapacity, structureID->propertyStorageCapacity());
+
+    ASSERT(offset < structureID->propertyStorageCapacity());
+    m_propertyStorage[offset] = value;
+    slot.setNewProperty(this, offset);
+    slot.setWasTransition(true);
+    setStructureID(structureID.release());
 }
 
 inline void JSObject::transitionTo(StructureID* newStructureID)
 {
-    StructureID::transitionTo(m_structureID, newStructureID, this);
+    if (m_structureID->propertyStorageCapacity() != newStructureID->propertyStorageCapacity())
+        allocatePropertyStorage(m_structureID->propertyStorageCapacity(), newStructureID->propertyStorageCapacity());
     setStructureID(newStructureID);
 }