Changeset 39625 in webkit for trunk/JavaScriptCore/interpreter/Interpreter.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/interpreter/Interpreter.cpp (modified) (6 diffs)

trunk/JavaScriptCore/interpreter/Interpreter.cpp

@@ -41 +41 @@
 #include "JSActivation.h"
 #include "JSArray.h"
+#include "JSByteArray.h"
 #include "JSFunction.h"
 #include "JSNotAnObject.h"
@@ -607 +608 @@
     m_jsArrayVptr = jsArray->vptr();
     jsArray->~JSCell();
+
+    JSByteArray* jsByteArray = new (storage) JSByteArray(JSByteArray::VPtrStealingHack);
+    m_jsByteArrayVptr = jsByteArray->vptr();
+    jsByteArray->~JSCell();
 
     JSCell* jsString = new (storage) JSString(JSString::VPtrStealingHack);
@@ -2854 +2859 @@
             } else if (isJSString(baseValue) && asString(baseValue)->canGetIndex(i))
                 result = asString(baseValue)->getIndex(&callFrame->globalData(), i);
+            else if (isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i))
+                result = asByteArray(baseValue)->getIndex(i);
             else
                 result = baseValue->get(callFrame, i);
@@ -2894 +2901 @@
                 else
                     jsArray->JSArray::put(callFrame, i, callFrame[value].jsValue(callFrame));
+            } else if (isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
+                JSByteArray* jsByteArray = asByteArray(baseValue);
+                double dValue = 0;
+                JSValue* jsValue = callFrame[value].jsValue(callFrame);
+                if (JSImmediate::isNumber(jsValue))
+                    jsByteArray->setIndex(i, JSImmediate::getTruncatedInt32(jsValue));
+                else if (fastIsNumber(jsValue, dValue))
+                    jsByteArray->setIndex(i, dValue);
+                else
+                    baseValue->put(callFrame, i, jsValue);
             } else
                 baseValue->put(callFrame, i, callFrame[value].jsValue(callFrame));
@@ -5095 +5112 @@
                 result = jsArray->JSArray::get(callFrame, i);
         } else if (interpreter->isJSString(baseValue) && asString(baseValue)->canGetIndex(i))
-            result = asString(baseValue)->getIndex(ARG_globalData, i);
+            return asString(baseValue)->getIndex(ARG_globalData, i);
+        else if (interpreter->isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i))
+            return asByteArray(baseValue)->getIndex(i);
         else
             result = baseValue->get(callFrame, i);
@@ -5188 +5207 @@
             else
                 jsArray->JSArray::put(callFrame, i, value);
+        } else if (interpreter->isJSByteArray(baseValue) && asByteArray(baseValue)->canAccessIndex(i)) {
+            JSByteArray* jsByteArray = asByteArray(baseValue);
+            double dValue = 0;
+            if (JSImmediate::isNumber(value)) {
+                jsByteArray->setIndex(i, JSImmediate::getTruncatedInt32(value));
+                return;
+            } else if (fastIsNumber(value, dValue)) {
+                jsByteArray->setIndex(i, dValue);
+                return;
+            } else
+                baseValue->put(callFrame, i, value);
         } else
             baseValue->put(callFrame, i, value);