Changeset 36804 in webkit for trunk/JavaScriptCore/kjs/Arguments.cpp

Timestamp:

Sep 23, 2008, 3:59:42 AM (17 years ago)

Author:

[email protected]

Message:

2008-09-23 Cameron Zwarich <​[email protected]>

Reviewed by Oliver Hunt.

Bug 20989: Aguments constructor should put 'callee' and 'length' properties in a more efficient way
<​https://bugs.webkit.org/show_bug.cgi?id=20989>

Make special cases for the 'callee' and 'length' properties in the
Arguments object.

This is somewhere between a 7.8% speedup and a 10% speedup on the V8
Raytrace benchmark, depending on whether it is run alone or with the
other V8 benchmarks.

• kjs/Arguments.cpp: (JSC::ArgumentsData::ArgumentsData): (JSC::Arguments::Arguments): (JSC::Arguments::mark): (JSC::Arguments::getOwnPropertySlot): (JSC::Arguments::put): (JSC::Arguments::deleteProperty):

File:

• trunk/JavaScriptCore/kjs/Arguments.cpp (modified) (8 diffs)

trunk/JavaScriptCore/kjs/Arguments.cpp

@@ -39 +39 @@
 
 struct ArgumentsData : Noncopyable {
-    ArgumentsData(JSActivation* activation, unsigned numParameters, unsigned firstArgumentIndex, unsigned numArguments)
+    ArgumentsData(JSActivation* activation, unsigned numParameters, unsigned firstArgumentIndex, unsigned numArguments, JSFunction* callee)
         : activation(activation)
         , numParameters(numParameters)
@@ -45 +45 @@
         , numArguments(numArguments)
         , extraArguments(0)
+        , callee(callee)
+        , overrodeLength(false)
+        , overrodeCallee(false)
     {
     }
 
     JSActivation* activation;
+
     unsigned numParameters;
     unsigned firstArgumentIndex;
@@ -55 +59 @@
     OwnArrayPtr<bool> deletedArguments;
     Register extraArgumentsFixedBuffer[4];
+
+    JSFunction* callee;
+    bool overrodeLength : 1;
+    bool overrodeCallee : 1;
 };
 
@@ -60 +68 @@
 Arguments::Arguments(ExecState* exec, JSFunction* function, JSActivation* activation, int firstArgumentIndex, Register* argv, int argc)
     : JSObject(exec->lexicalGlobalObject()->argumentsStructure())
-    , d(new ArgumentsData(activation, function->numParameters(), firstArgumentIndex, argc))
+    , d(new ArgumentsData(activation, function->numParameters(), firstArgumentIndex, argc, function))
 {
     ASSERT(activation);
-
-    putDirect(exec->propertyNames().callee, function, DontEnum);
-    putDirect(exec->propertyNames().length, jsNumber(exec, argc), DontEnum);
   
     if (d->numArguments > d->numParameters) {
@@ -98 +103 @@
     }
 
+    if (!d->callee->marked())
+        d->callee->mark();
+
     if (!d->activation->marked())
         d->activation->mark();
@@ -165 +173 @@
     }
 
+    if (propertyName == exec->propertyNames().length && LIKELY(!d->overrodeLength)) {
+        slot.setValue(jsNumber(exec, d->numArguments));
+        return true;
+    }
+
+    if (propertyName == exec->propertyNames().callee && LIKELY(!d->overrodeCallee)) {
+        slot.setValue(d->callee);
+        return true;
+    }
+
     return JSObject::getOwnPropertySlot(exec, propertyName, slot);
 }
@@ -190 +208 @@
         else
             d->extraArguments[i - d->numParameters] = value;
+        return;
+    }
+
+    if (propertyName == exec->propertyNames().length && !d->overrodeLength) {
+        d->overrodeLength = true;
+        putDirect(propertyName, value, DontEnum);
+        return;
+    }
+
+    if (propertyName == exec->propertyNames().callee && !d->overrodeCallee) {
+        d->overrodeCallee = true;
+        putDirect(propertyName, value, DontEnum);
         return;
     }
@@ -227 +257 @@
     }
 
+    if (propertyName == exec->propertyNames().length && !d->overrodeLength) {
+        d->overrodeLength = true;
+        return true;
+    }
+
+    if (propertyName == exec->propertyNames().callee && !d->overrodeCallee) {
+        d->overrodeCallee = true;
+        return true;
+    }
+
     return JSObject::deleteProperty(exec, propertyName);
 }