V4: Pass scope around as parameters inside the runtime.

The implementation of many (or all) runtime functions consist of first
creating a QV4::Scope, which saves and restores the JS stack pointer.
It also prevents tail-calls because of that restoring behavior. In many
cases it suffices to do that at the entry-point of the runtime.

The return value of a JS function call is now also stored in the scope.
Previously, all return values were stored in a ScopedValue, got loaded
on return, and immediately stored in another ScopedValue in the caller.
This resulted in a lot of stores, where now there is only one store
needed, and no extra ScopedValue for every function.

Change-Id: I13d80fc0ce72c5702ef1536d41d12f710c5914fa
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 2 insertions, 3 deletions

diff --git a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
index 482da31779..a0dff482b1 100644
--- a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
+++ b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
@@ -1285,11 +1285,10 @@ void QQmlBindingFunction::initBindingLocation()
     d()->bindingLocation.line = frame.line;
 }
 
-ReturnedValue QQmlBindingFunction::call(const Managed *that, CallData *callData)
+void QQmlBindingFunction::call(const Managed *that, Scope &scope, CallData *callData)
 {
-    Scope scope(static_cast<const QQmlBindingFunction*>(that)->engine());
     ScopedFunctionObject function(scope, static_cast<const QQmlBindingFunction*>(that)->d()->originalFunction);
-    return function->call(callData);
+    function->call(scope, callData);
 }
 
 void QQmlBindingFunction::markObjects(Heap::Base *that, ExecutionEngine *e)