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, 6 insertions, 6 deletions

diff --git a/src/qml/jsruntime/qv4dateobject.cpp b/src/qml/jsruntime/qv4dateobject.cpp
index 0cd72d6811..6acc76cdd8 100644
--- a/src/qml/jsruntime/qv4dateobject.cpp
+++ b/src/qml/jsruntime/qv4dateobject.cpp
@@ -651,9 +651,8 @@ Heap::DateCtor::DateCtor(QV4::ExecutionContext *scope)
 {
 }
 
-ReturnedValue DateCtor::construct(const Managed *m, CallData *callData)
+void DateCtor::construct(const Managed *, Scope &scope, CallData *callData)
 {
-    Scope scope(static_cast<const DateCtor *>(m)->engine());
     double t = 0;
 
     if (callData->argc == 0)
@@ -687,13 +686,13 @@ ReturnedValue DateCtor::construct(const Managed *m, CallData *callData)
         t = TimeClip(UTC(t));
     }
 
-    return Encode(scope.engine->newDateObject(Primitive::fromDouble(t)));
+    scope.result = Encode(scope.engine->newDateObject(Primitive::fromDouble(t)));
 }
 
-ReturnedValue DateCtor::call(const Managed *m, CallData *)
+void DateCtor::call(const Managed *m, Scope &scope, CallData *)
 {
     double t = currentTime();
-    return static_cast<const DateCtor *>(m)->engine()->newString(ToString(t))->asReturnedValue();
+    scope.result = static_cast<const DateCtor *>(m)->engine()->newString(ToString(t));
 }
 
 void DatePrototype::init(ExecutionEngine *engine, Object *ctor)
@@ -1311,7 +1310,8 @@ ReturnedValue DatePrototype::method_toJSON(CallContext *ctx)
 
     ScopedCallData callData(scope);
     callData->thisObject = ctx->thisObject();
-    return toIso->call(callData);
+    toIso->call(scope, callData);
+    return scope.result.asReturnedValue();
 }
 
 void DatePrototype::timezoneUpdated()