Optimize Arguments Object

Avoid creation of the Array in most cases. Fix FunctionObject::method_apply
so that it correctly recognizes this case and does the right thing.
Add a getLength() method to ArgumentsObject to speed up the lookup of that
property.

Improves the RayTrace benchmark by around 15%.

Change-Id: I53eb34a1f9515e59a191ee6f0eb23a3f4c6882d1
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 8 insertions, 2 deletions

diff --git a/src/qml/jsruntime/qv4argumentsobject.cpp b/src/qml/jsruntime/qv4argumentsobject.cpp
index 74fcd30632..5a190d6690 100644
--- a/src/qml/jsruntime/qv4argumentsobject.cpp
+++ b/src/qml/jsruntime/qv4argumentsobject.cpp
@@ -57,8 +57,6 @@ void Heap::ArgumentsObject::init(QV4::CallContext *context)
     Scope scope(v4);
     Scoped<QV4::ArgumentsObject> args(scope, this);
 
-    args->setArrayType(Heap::ArrayData::Complex);
-
     if (context->d()->strictMode) {
         Q_ASSERT(CalleePropertyIndex == args->internalClass()->find(context->d()->engine->id_callee()));
         Q_ASSERT(CallerPropertyIndex == args->internalClass()->find(context->d()->engine->id_caller()));
@@ -246,3 +244,11 @@ void ArgumentsObject::markObjects(Heap::Base *that, ExecutionEngine *e)
 
     Object::markObjects(that, e);
 }
+
+uint ArgumentsObject::getLength(const Managed *m)
+{
+    const ArgumentsObject *a = static_cast<const ArgumentsObject *>(m);
+    if (a->propertyData(Heap::ArgumentsObject::LengthPropertyIndex)->isInteger())
+        return a->propertyData(Heap::ArgumentsObject::LengthPropertyIndex)->integerValue();
+    return Primitive::toUInt32(a->propertyData(Heap::ArgumentsObject::LengthPropertyIndex)->doubleValue());
+}