Changeset 34867 in webkit for trunk/JavaScriptCore/kjs/JSArray.h

Timestamp:

Jun 28, 2008, 8:56:04 PM (17 years ago)

Author:

Darin Adler

Message:

2008-06-28 Darin Adler <Darin Adler>

Reviewed by Cameron.

• ​https://bugs.webkit.org/show_bug.cgi?id=19804 optimize access to arrays without "holes"

SunSpider says 1.8% faster.

• kjs/JSArray.cpp: (KJS::JSArray::JSArray): Initialize m_fastAccessCutoff when creating arrays. Also updated for new location of m_vectorLength. (KJS::JSArray::getItem): Updated for new location of m_vectorLength. (KJS::JSArray::getSlowCase): Added. Broke out the non-hot parts of getOwnPropertySlot to make the hot part faster. (KJS::JSArray::getOwnPropertySlot): Added a new faster case for indices lower than m_fastAccessCutoff. We can do theese with no additional checks or branches. (KJS::JSArray::put): Added a new faster case for indices lower than m_fastAccessCutoff. We can do theese with no additional checks or branches. Moved the maxArrayIndex handling out of this function. Added code to set m_fastAccessCutoff when the very last hole in an array is filled; this is how the cutoff gets set for most arrays. (KJS::JSArray::putSlowCase): Moved the rest of the put function logic in here, to make the hot part of the put function faster. (KJS::JSArray::deleteProperty): Added code to lower m_fastAccessCutoff when a delete makes a new hole in the array. (KJS::JSArray::getPropertyNames): Updated for new location of m_vectorLength. (KJS::JSArray::increaseVectorLength): Ditto. (KJS::JSArray::setLength): Added code to lower m_fastAccessCutoff when setLength makes the array smaller. (KJS::JSArray::mark): Updated for new location of m_vectorLength. (KJS::JSArray::sort): Ditto. Set m_fastAccessCutoff after moving all the holes to the end of the array. (KJS::JSArray::compactForSorting): Ditto. (KJS::JSArray::checkConsistency): Added consistency checks fro m_fastAccessCutoff and updated for the new location of m_vectorLength.

• kjs/JSArray.h: Added declarations for slow case functions. Replaced m_vectorLength with m_fastAccessCutoff.

File:

• trunk/JavaScriptCore/kjs/JSArray.h (modified) (2 diffs)

trunk/JavaScriptCore/kjs/JSArray.h

@@ -64 +64 @@
 
     static JSValue* lengthGetter(ExecState*, const Identifier&, const PropertySlot&);
-    bool inlineGetOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
+
+    bool getOwnPropertySlotSlowCase(ExecState*, unsigned propertyName, PropertySlot&);
+    void putSlowCase(ExecState*, unsigned propertyName, JSValue*);
 
     bool increaseVectorLength(unsigned newLength);
@@ -74 +76 @@
 
     unsigned m_length;
-    unsigned m_vectorLength;
+    unsigned m_fastAccessCutoff;
     ArrayStorage* m_storage;
   };