Changeset 175462 in webkit

Timestamp:

Nov 2, 2014 8:37:59 AM (9 years ago)

Author:

Chris Dumez

Message:

Reduce the cost of argumentCount checks in the JS bindings
​https://bugs.webkit.org/show_bug.cgi?id=138289

Reviewed by Sam Weinig.

Slightly reduce the cost of argumentCount checks in the JS bindings by
hinting to the compiler that it is UNLIKELY that those methods are
called with too few arguments.

I see a 3% progression on PerformanceTests/DOM/DOMDivWalk.html
performance test.

No new tests, no behavior change.

• bindings/scripts/CodeGeneratorJS.pm:

(GenerateArgumentsCountCheck):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• bindings/scripts/CodeGeneratorJS.pm (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2014-11-02  Chris Dumez  <cdumez@apple.com>
+
+        Reduce the cost of argumentCount checks in the JS bindings
+        https://bugs.webkit.org/show_bug.cgi?id=138289
+
+        Reviewed by Sam Weinig.
+
+        Slightly reduce the cost of argumentCount checks in the JS bindings by
+        hinting to the compiler that it is UNLIKELY that those methods are
+        called with too few arguments.
+
+        I see a 3% progression on PerformanceTests/DOM/DOMDivWalk.html
+        performance test.
+
+        No new tests, no behavior change.
+
+        * bindings/scripts/CodeGeneratorJS.pm:
+        (GenerateArgumentsCountCheck):
+
 2014-11-01  Alexey Proskuryakov  <ap@apple.com>
 

trunk/Source/WebCore/bindings/scripts/CodeGeneratorJS.pm

@@ -3167 +3167 @@
     if ($numMandatoryParams >= 1)
     {
-        push(@$outputArray, "    if (exec->argumentCount() < $numMandatoryParams)\n");
+        push(@$outputArray, "    if (UNLIKELY(exec->argumentCount() < $numMandatoryParams))\n");
         push(@$outputArray, "        return throwVMError(exec, createNotEnoughArgumentsError(exec));\n");
     }