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, 9 insertions, 9 deletions

diff --git a/src/qml/jsapi/qjsvalue.cpp b/src/qml/jsapi/qjsvalue.cpp
index 44746b8c2b..e5c1dcdb80 100644
--- a/src/qml/jsapi/qjsvalue.cpp
+++ b/src/qml/jsapi/qjsvalue.cpp
@@ -663,11 +663,11 @@ QJSValue QJSValue::call(const QJSValueList &args)
         callData->args[i] = QJSValuePrivate::convertedToValue(engine, args.at(i));
     }
 
-    ScopedValue result(scope, f->call(callData));
+    f->call(scope, callData);
     if (engine->hasException)
-        result = engine->catchException();
+        scope.result = engine->catchException();
 
-    return QJSValue(engine, result->asReturnedValue());
+    return QJSValue(engine, scope.result.asReturnedValue());
 }
 
 /*!
@@ -719,11 +719,11 @@ QJSValue QJSValue::callWithInstance(const QJSValue &instance, const QJSValueList
         callData->args[i] = QJSValuePrivate::convertedToValue(engine, args.at(i));
     }
 
-    ScopedValue result(scope, f->call(callData));
+    f->call(scope, callData);
     if (engine->hasException)
-        result = engine->catchException();
+        scope.result = engine->catchException();
 
-    return QJSValue(engine, result->asReturnedValue());
+    return QJSValue(engine, scope.result.asReturnedValue());
 }
 
 /*!
@@ -767,11 +767,11 @@ QJSValue QJSValue::callAsConstructor(const QJSValueList &args)
         callData->args[i] = QJSValuePrivate::convertedToValue(engine, args.at(i));
     }
 
-    ScopedValue result(scope, f->construct(callData));
+    f->construct(scope, callData);
     if (engine->hasException)
-        result = engine->catchException();
+        scope.result = engine->catchException();
 
-    return QJSValue(engine, result->asReturnedValue());
+    return QJSValue(engine, scope.result.asReturnedValue());
 }
 
 #ifdef QT_DEPRECATED