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, 4 insertions, 5 deletions

diff --git a/src/qml/jsruntime/qv4booleanobject.cpp b/src/qml/jsruntime/qv4booleanobject.cpp
index d9da7d7754..57c54e15c4 100644
--- a/src/qml/jsruntime/qv4booleanobject.cpp
+++ b/src/qml/jsruntime/qv4booleanobject.cpp
@@ -50,17 +50,16 @@ Heap::BooleanCtor::BooleanCtor(QV4::ExecutionContext *scope)
 {
 }
 
-ReturnedValue BooleanCtor::construct(const Managed *m, CallData *callData)
+void BooleanCtor::construct(const Managed *, Scope &scope, CallData *callData)
 {
-    Scope scope(static_cast<const BooleanCtor *>(m)->engine());
     bool n = callData->argc ? callData->args[0].toBoolean() : false;
-    return Encode(scope.engine->newBooleanObject(n));
+    scope.result = Encode(scope.engine->newBooleanObject(n));
 }
 
-ReturnedValue BooleanCtor::call(const Managed *, CallData *callData)
+void BooleanCtor::call(const Managed *, Scope &scope, CallData *callData)
 {
     bool value = callData->argc ? callData->args[0].toBoolean() : 0;
-    return Encode(value);
+    scope.result = Encode(value);
 }
 
 void BooleanPrototype::init(ExecutionEngine *engine, Object *ctor)