Changeset 39625 in webkit for trunk/JavaScriptCore/runtime/ByteArray.cpp

Timestamp:

Jan 5, 2009, 3:57:09 PM (16 years ago)

Author:

[email protected]

Message:

CanvasPixelArray performance is too slow
<​https://bugs.webkit.org/show_bug.cgi?id=23123>

Reviewed by Gavin Barraclough

JavaScriptCore:
The fix to this is to devirtualise get and put in a manner similar to
JSString and JSArray. To do this I've added a ByteArray implementation
and JSByteArray wrapper to JSC. We can then do vptr comparisons to
devirtualise the calls.

This devirtualisation improves performance by 1.5-2x in my somewhat ad
hoc tests.

WebCore:
Remove the WebCore CanvasPixelArray implementation and replace
CPA usage with JSC::ByteArray. Replace the JSCanvasPixelArray
wrapper with an explicitly instantiated JSByteArray put on the
JSImageData object as an ordinary ReadOnly, DontDelete property.

File:

• trunk/JavaScriptCore/runtime/ByteArray.cpp (moved) (moved from trunk/WebCore/bindings/js/JSCanvasPixelArrayCustom.h ) (3 diffs)

trunk/JavaScriptCore/runtime/ByteArray.cpp

@@ -1 +1 @@
 /*
- * Copyright (C) 2008 Apple Inc. All rights reserved.
+ * Copyright (C) 2009 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -11 +11 @@
  *    documentation and/or other materials provided with the distribution.
  *
- * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
@@ -24 +24 @@
  */
 
-#include "JSCanvasPixelArray.h"
+#include "config.h"
+#include "ByteArray.h"
 
-#include "CanvasPixelArray.h"
+namespace JSC {
 
-using namespace JSC;
+PassRefPtr<ByteArray> ByteArray::create(size_t size)
+{
+    unsigned char* buffer = new unsigned char[size + sizeof(ByteArray)];
+    ASSERT((reinterpret_cast<size_t>(buffer) & 3) == 0);
+    return adoptRef(new (buffer) ByteArray(size));
+}
 
-namespace WebCore {
-    
-    inline JSValue* JSCanvasPixelArray::getByIndex(ExecState*, unsigned index)
-    {
-        unsigned char result;
-        if (!impl()->get(index, result))
-            return jsUndefined();
-        return JSImmediate::from(result);
-    }
-    
-    inline void JSCanvasPixelArray::indexSetter(ExecState* exec, unsigned index, JSValue* value)
-    {
-        double pixelValue = value->toNumber(exec);
-        if (exec->hadException())
-            return;
-        m_impl->set(index, pixelValue); 
-    }
-    
-} // namespace WebCore
+}