Changeset 36792 in webkit for trunk/JavaScriptCore/kjs/Arguments.cpp

Timestamp:

Sep 22, 2008, 9:55:51 PM (17 years ago)

Author:

Darin Adler

Message:

2008-09-22 Darin Adler <Darin Adler>

Reviewed by Cameron Zwarich.

• ​https://bugs.webkit.org/show_bug.cgi?id=20983 ArgumentsData should have some room to allocate some extra arguments inline

Speeds up v8-raytrace by 5%.

• kjs/Arguments.cpp: (JSC::ArgumentsData::ArgumentsData): Use a fixed buffer if there are 4 or fewer extra arguments. (JSC::Arguments::Arguments): Use a fixed buffer if there are 4 or fewer extra arguments. (JSC::Arguments::~Arguments): Delete the buffer if necessary. (JSC::Arguments::mark): Update since extraArguments are now Register. (JSC::Arguments::fillArgList): Added special case for the only case that's actually used in the practice, when there are no parameters. There are some other special cases in there too, but that's the only one that matters. (JSC::Arguments::getOwnPropertySlot): Updated to use setValueSlot since there's no operation to get you at the JSValue* inside a Register as a "slot".

File:

• trunk/JavaScriptCore/kjs/Arguments.cpp (modified) (11 diffs)

trunk/JavaScriptCore/kjs/Arguments.cpp

@@ -38 +38 @@
 const ClassInfo Arguments::info = { "Arguments", 0, 0, 0 };
 
-struct ArgumentsData {
+struct ArgumentsData : Noncopyable {
     ArgumentsData(JSActivation* activation, unsigned numParameters, unsigned firstArgumentIndex, unsigned numArguments)
         : activation(activation)
@@ -44 +44 @@
         , firstArgumentIndex(firstArgumentIndex)
         , numArguments(numArguments)
+        , extraArguments(0)
     {
     }
@@ -51 +52 @@
     unsigned firstArgumentIndex;
     unsigned numArguments;
-    OwnArrayPtr<JSValue*> extraArguments;
+    Register* extraArguments;
     OwnArrayPtr<bool> deletedArguments;
+    Register extraArgumentsFixedBuffer[4];
 };
 
@@ -67 +69 @@
     if (d->numArguments > d->numParameters) {
         unsigned numExtraArguments = d->numArguments - d->numParameters;
-        JSValue** extraArguments = new JSValue*[numExtraArguments];
+        Register* extraArguments;
+        if (numExtraArguments > sizeof(d->extraArgumentsFixedBuffer) / sizeof(Register))
+            extraArguments = new Register[numExtraArguments];
+        else
+            extraArguments = d->extraArgumentsFixedBuffer;
         for (unsigned i = 0; i < numExtraArguments; ++i)
-            extraArguments[i] = argv[d->numParameters + i].getJSValue();
-        d->extraArguments.set(extraArguments);
+            extraArguments[i] = argv[d->numParameters + i];
+        d->extraArguments = extraArguments;
     }
 }
@@ -76 +82 @@
 Arguments::~Arguments()
 {
+    if (d->extraArguments != d->extraArgumentsFixedBuffer)
+        delete [] d->extraArguments;
 }
 
@@ -85 +93 @@
         unsigned numExtraArguments = d->numArguments - d->numParameters;
         for (unsigned i = 0; i < numExtraArguments; ++i) {
-            if (!d->extraArguments[i]->marked())
-                d->extraArguments[i]->mark();
+            if (!d->extraArguments[i].marked())
+                d->extraArguments[i].mark();
         }
     }
@@ -96 +104 @@
 void Arguments::fillArgList(ExecState* exec, ArgList& args)
 {
-    if (!d->deletedArguments) {
+    if (LIKELY(!d->deletedArguments)) {
+        if (LIKELY(!d->numParameters)) {
+            args.initialize(d->extraArguments, d->numArguments);
+            return;
+        }
+
         if (d->numParameters == d->numArguments) {
             args.initialize(&d->activation->registerAt(d->firstArgumentIndex), d->numArguments);
@@ -107 +120 @@
             args.append(d->activation->uncheckedSymbolTableGetValue(d->firstArgumentIndex + i));
         for (; i < d->numArguments; ++i)
-            args.append(d->extraArguments[i - d->numParameters]);
+            args.append(get(exec, i));
         return;
     }
@@ -121 +134 @@
     for (; i < d->numArguments; ++i) {
         if (!d->deletedArguments[i])
-            args.append(d->extraArguments[i - d->numParameters]);
+            args.append(d->extraArguments[i - d->numParameters].getJSValue());
         else
             args.append(get(exec, i));
@@ -133 +146 @@
             d->activation->uncheckedSymbolTableGet(d->firstArgumentIndex + i, slot);
         else
-            slot.setValueSlot(&d->extraArguments[i - d->numParameters]);
+            slot.setValue(d->extraArguments[i - d->numParameters].getJSValue());
         return true;
     }
@@ -148 +161 @@
             d->activation->uncheckedSymbolTableGet(d->firstArgumentIndex + i, slot);
         else
-            slot.setValueSlot(&d->extraArguments[i - d->numParameters]);
+            slot.setValue(d->extraArguments[i - d->numParameters].getJSValue());
         return true;
     }