Remove double indirection between QJSEngine and QV4::ExecutionEngine

As QJSEngine's handle() method is internal, we can redefine it to return
a pointer to an ExecutionEngine. That makes many things easier.

Change-Id: Ie3df99e0bad5f00ad4fe73182896cd135fa82994
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

24 files changed, 129 insertions, 137 deletions

diff --git a/src/qml/compiler/qqmltypecompiler.cpp b/src/qml/compiler/qqmltypecompiler.cpp
index 836aa8c416..62bddd2509 100644
--- a/src/qml/compiler/qqmltypecompiler.cpp
+++ b/src/qml/compiler/qqmltypecompiler.cpp
@@ -295,7 +295,7 @@ SignalHandlerConverter::SignalHandlerConverter(QQmlTypeCompiler *typeCompiler)
     , imports(typeCompiler->imports())
     , customParsers(typeCompiler->customParserCache())
     , resolvedTypes(typeCompiler->resolvedTypes)
-    , illegalNames(QV8Engine::get(QQmlEnginePrivate::get(typeCompiler->enginePrivate()))->illegalNames())
+    , illegalNames(typeCompiler->enginePrivate()->v8engine()->illegalNames())
     , propertyCaches(typeCompiler->propertyCaches())
 {
 }
diff --git a/src/qml/jsapi/qjsengine.cpp b/src/qml/jsapi/qjsengine.cpp
index fffb190513..020a83f837 100644
--- a/src/qml/jsapi/qjsengine.cpp
+++ b/src/qml/jsapi/qjsengine.cpp
@@ -290,8 +290,9 @@ QJSEngine::QJSEngine()
 
 QJSEngine::QJSEngine(QObject *parent)
     : QObject(*new QJSEnginePrivate, parent)
-    , d(new QV8Engine(this))
+    , m_v4Engine(new QV4::ExecutionEngine)
 {
+    m_v4Engine->v8Engine = new QV8Engine(this, m_v4Engine);
     checkForApplicationInstance();
 
     QJSEnginePrivate::addToDebugServer(this);
@@ -302,8 +303,9 @@ QJSEngine::QJSEngine(QObject *parent)
 */
 QJSEngine::QJSEngine(QJSEnginePrivate &dd, QObject *parent)
     : QObject(dd, parent)
-    , d(new QV8Engine(this))
+    , m_v4Engine(new QV4::ExecutionEngine)
 {
+    m_v4Engine->v8Engine = new QV8Engine(this, m_v4Engine);
     checkForApplicationInstance();
 }
 
@@ -317,11 +319,12 @@ QJSEngine::QJSEngine(QJSEnginePrivate &dd, QObject *parent)
 QJSEngine::~QJSEngine()
 {
     QJSEnginePrivate::removeFromDebugServer(this);
-    delete d;
+    delete m_v4Engine->v8Engine;
+    delete m_v4Engine;
 }
 
 /*!
-    \fn QV8Engine *QJSEngine::handle() const
+    \fn QV4::ExecutionEngine *QJSEngine::handle() const
     \internal
 */
 
@@ -338,7 +341,7 @@ QJSEngine::~QJSEngine()
 */
 void QJSEngine::collectGarbage()
 {
-    d->m_v4Engine->memoryManager->runGC();
+    m_v4Engine->memoryManager->runGC();
 }
 
 #if QT_DEPRECATED_SINCE(5, 6)
@@ -395,12 +398,12 @@ void QJSEngine::installTranslatorFunctions(const QJSValue &object)
 void QJSEngine::installExtensions(QJSEngine::Extensions extensions, const QJSValue &object)
 {
     QV4::ExecutionEngine *otherEngine = QJSValuePrivate::engine(&object);
-    if (otherEngine && otherEngine != d->m_v4Engine) {
+    if (otherEngine && otherEngine != m_v4Engine) {
         qWarning("QJSEngine: Trying to install extensions from a different engine");
         return;
     }
 
-    QV4::Scope scope(d->m_v4Engine);
+    QV4::Scope scope(m_v4Engine);
     QV4::ScopedObject obj(scope);
     QV4::Value *val = QJSValuePrivate::getValue(&object);
     if (val)
@@ -441,7 +444,7 @@ void QJSEngine::installExtensions(QJSEngine::Extensions extensions, const QJSVal
 */
 QJSValue QJSEngine::evaluate(const QString& program, const QString& fileName, int lineNumber)
 {
-    QV4::ExecutionEngine *v4 = d->m_v4Engine;
+    QV4::ExecutionEngine *v4 = m_v4Engine;
     QV4::Scope scope(v4);
     QV4::ScopedValue result(scope);
 
@@ -473,9 +476,9 @@ QJSValue QJSEngine::evaluate(const QString& program, const QString& fileName, in
 */
 QJSValue QJSEngine::newObject()
 {
-    QV4::Scope scope(d->m_v4Engine);
-    QV4::ScopedValue v(scope, d->m_v4Engine->newObject());
-    return QJSValue(d->m_v4Engine, v->asReturnedValue());
+    QV4::Scope scope(m_v4Engine);
+    QV4::ScopedValue v(scope, m_v4Engine->newObject());
+    return QJSValue(m_v4Engine, v->asReturnedValue());
 }
 
 /*!
@@ -485,12 +488,12 @@ QJSValue QJSEngine::newObject()
 */
 QJSValue QJSEngine::newArray(uint length)
 {
-    QV4::Scope scope(d->m_v4Engine);
-    QV4::ScopedArrayObject array(scope, d->m_v4Engine->newArrayObject());
+    QV4::Scope scope(m_v4Engine);
+    QV4::ScopedArrayObject array(scope, m_v4Engine->newArrayObject());
     if (length < 0x1000)
         array->arrayReserve(length);
     array->setArrayLengthUnchecked(length);
-    return QJSValue(d->m_v4Engine, array.asReturnedValue());
+    return QJSValue(m_v4Engine, array.asReturnedValue());
 }
 
 /*!
@@ -516,7 +519,7 @@ QJSValue QJSEngine::newArray(uint length)
 QJSValue QJSEngine::newQObject(QObject *object)
 {
     Q_D(QJSEngine);
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(d);
+    QV4::ExecutionEngine *v4 = m_v4Engine;
     QV4::Scope scope(v4);
     if (object) {
         QQmlData *ddata = QQmlData::get(object, true);
@@ -543,7 +546,7 @@ QJSValue QJSEngine::newQObject(QObject *object)
 
 QJSValue QJSEngine::newQMetaObject(const QMetaObject* metaObject) {
     Q_D(QJSEngine);
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(d);
+    QV4::ExecutionEngine *v4 = m_v4Engine;
     QV4::Scope scope(v4);
     QV4::ScopedValue v(scope, QV4::QMetaObjectWrapper::create(v4, metaObject));
     return QJSValue(v4, v->asReturnedValue());
@@ -571,10 +574,9 @@ QJSValue QJSEngine::newQMetaObject(const QMetaObject* metaObject) {
 */
 QJSValue QJSEngine::globalObject() const
 {
-    Q_D(const QJSEngine);
-    QV4::Scope scope(d->m_v4Engine);
-    QV4::ScopedValue v(scope, d->m_v4Engine->globalObject);
-    return QJSValue(d->m_v4Engine, v->asReturnedValue());
+    QV4::Scope scope(m_v4Engine);
+    QV4::ScopedValue v(scope, m_v4Engine->globalObject);
+    return QJSValue(m_v4Engine, v->asReturnedValue());
 }
 
 /*!
@@ -583,10 +585,9 @@ QJSValue QJSEngine::globalObject() const
  */
 QJSValue QJSEngine::create(int type, const void *ptr)
 {
-    Q_D(QJSEngine);
-    QV4::Scope scope(d->m_v4Engine);
+    QV4::Scope scope(m_v4Engine);
     QV4::ScopedValue v(scope, scope.engine->metaTypeToJS(type, ptr));
-    return QJSValue(d->m_v4Engine, v->asReturnedValue());
+    return QJSValue(m_v4Engine, v->asReturnedValue());
 }
 
 /*!
@@ -726,7 +727,7 @@ bool QJSEngine::convertV2(const QJSValue &value, int type, void *ptr)
 
 QJSEnginePrivate *QJSEnginePrivate::get(QV4::ExecutionEngine *e)
 {
-    return e->v8Engine->publicEngine()->d_func();
+    return e->jsEngine()->d_func();
 }
 
 QJSEnginePrivate::~QJSEnginePrivate()
diff --git a/src/qml/jsapi/qjsengine.h b/src/qml/jsapi/qjsengine.h
index 913757107f..89642b6f20 100644
--- a/src/qml/jsapi/qjsengine.h
+++ b/src/qml/jsapi/qjsengine.h
@@ -52,8 +52,6 @@
 QT_BEGIN_NAMESPACE
 
 
-class QV8Engine;
-
 template <typename T>
 inline T qjsvalue_cast(const QJSValue &);
 
@@ -111,7 +109,7 @@ public:
 
     void installExtensions(Extensions extensions, const QJSValue &object = QJSValue());
 
-    QV8Engine *handle() const { return d; }
+    QV4::ExecutionEngine *handle() const { return m_v4Engine; }
 
 private:
     QJSValue create(int type, const void *ptr);
@@ -124,10 +122,9 @@ protected:
     QJSEngine(QJSEnginePrivate &dd, QObject *parent = nullptr);
 
 private:
-    QV8Engine *d;
+    QV4::ExecutionEngine *m_v4Engine;
     Q_DISABLE_COPY(QJSEngine)
     Q_DECLARE_PRIVATE(QJSEngine)
-    friend class QV8Engine;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QJSEngine::Extensions)
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 167a40bc51..85a93ce2e3 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -1552,6 +1552,11 @@ QV4::ReturnedValue ExecutionEngine::metaTypeToJS(int type, const void *data)
     return 0;
 }
 
+ReturnedValue ExecutionEngine::global()
+{
+    return globalObject->asReturnedValue();
+}
+
 // Converts a JS value to a meta-type.
 // data must point to a place that can store a value of the given type.
 // Returns true if conversion succeeded, false otherwise.
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index 44f57299bb..c048f5f68d 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -494,6 +494,8 @@ public:
 #endif
     }
 
+    QV4::ReturnedValue global();
+
 private:
 #if QT_CONFIG(qml_debug)
     QScopedPointer<QV4::Debugging::Debugger> m_debugger;
diff --git a/src/qml/qml/qqmlbinding.cpp b/src/qml/qml/qqmlbinding.cpp
index 11a1e6edee..a968aa908d 100644
--- a/src/qml/qml/qqmlbinding.cpp
+++ b/src/qml/qml/qqmlbinding.cpp
@@ -84,7 +84,7 @@ QQmlBinding *QQmlBinding::create(const QQmlPropertyData *property, const QQmlScr
     b->QQmlJavaScriptExpression::setContext(QQmlContextData::get(ctxt ? ctxt : scriptPrivate->context));
     b->setScopeObject(obj ? obj : scriptPrivate->scope);
 
-    QV4::ExecutionEngine *v4 = QQmlEnginePrivate::get(b->context()->engine)->v4engine();
+    QV4::ExecutionEngine *v4 = b->context()->engine->handle();
     if (runtimeFunction) {
         QV4::Scope scope(v4);
         QV4::Scoped<QV4::QmlContext> qmlContext(scope, QV4::QmlContext::create(v4->rootContext(), ctxtdata, b->scopeObject()));
@@ -158,13 +158,13 @@ void QQmlBinding::update(QQmlPropertyData::WriteFlags flags)
 
     DeleteWatcher watcher(this);
 
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(context()->engine);
-    QV4::Scope scope(ep->v4engine());
+    QQmlEngine *engine = context()->engine;
+    QV4::Scope scope(engine->handle());
 
     if (canUseAccessor())
         flags.setFlag(QQmlPropertyData::BypassInterceptor);
 
-    QQmlBindingProfiler prof(ep->profiler, function());
+    QQmlBindingProfiler prof(QQmlEnginePrivate::get(engine)->profiler, function());
     doUpdate(watcher, flags, scope);
 
     if (!watcher.wasDeleted())
@@ -351,7 +351,7 @@ Q_NEVER_INLINE bool QQmlBinding::slowWrite(const QQmlPropertyData &core,
                                            bool isUndefined, QQmlPropertyData::WriteFlags flags)
 {
     QQmlEngine *engine = context()->engine;
-    QV8Engine *v8engine = QQmlEnginePrivate::getV8Engine(engine);
+    QV4::ExecutionEngine *v4engine = engine->handle();
 
     int type = valueTypeData.isValid() ? valueTypeData.propType() : core.propType();
 
@@ -362,13 +362,13 @@ Q_NEVER_INLINE bool QQmlBinding::slowWrite(const QQmlPropertyData &core,
 
     if (isUndefined) {
     } else if (core.isQList()) {
-        value = QV8Engine::getV4(v8engine)->toVariant(result, qMetaTypeId<QList<QObject *> >());
+        value = v4engine->toVariant(result, qMetaTypeId<QList<QObject *> >());
     } else if (result.isNull() && core.isQObject()) {
         value = QVariant::fromValue((QObject *)0);
     } else if (core.propType() == qMetaTypeId<QList<QUrl> >()) {
-        value = QQmlPropertyPrivate::resolvedUrlSequence(QV8Engine::getV4(v8engine)->toVariant(result, qMetaTypeId<QList<QUrl> >()), context());
+        value = QQmlPropertyPrivate::resolvedUrlSequence(v4engine->toVariant(result, qMetaTypeId<QList<QUrl> >()), context());
     } else if (!isVarProperty && type != qMetaTypeId<QJSValue>()) {
-        value = QV8Engine::getV4(v8engine)->toVariant(result, type);
+        value = v4engine->toVariant(result, type);
     }
 
     if (hasError()) {
@@ -397,7 +397,7 @@ Q_NEVER_INLINE bool QQmlBinding::slowWrite(const QQmlPropertyData &core,
             return false;
         }
         QQmlPropertyPrivate::writeValueProperty(m_target.data(), core, valueTypeData, QVariant::fromValue(
-                               QJSValue(QV8Engine::getV4(v8engine), result.asReturnedValue())),
+                               QJSValue(v4engine, result.asReturnedValue())),
                            context(), flags);
     } else if (isUndefined) {
         const QLatin1String typeName(QMetaType::typeName(type)
@@ -455,12 +455,13 @@ Q_NEVER_INLINE bool QQmlBinding::slowWrite(const QQmlPropertyData &core,
 
 QVariant QQmlBinding::evaluate()
 {
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(context()->engine);
+    QQmlEngine *engine = context()->engine;
+    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
     ep->referenceScarceResources();
 
     bool isUndefined = false;
 
-    QV4::Scope scope(ep->v4engine());
+    QV4::Scope scope(engine->handle());
     QV4::ScopedValue result(scope, QQmlJavaScriptExpression::evaluate(&isUndefined));
 
     ep->dereferenceScarceResources();
diff --git a/src/qml/qml/qqmlboundsignal.cpp b/src/qml/qml/qqmlboundsignal.cpp
index 1d7a37fc99..501184b630 100644
--- a/src/qml/qml/qqmlboundsignal.cpp
+++ b/src/qml/qml/qqmlboundsignal.cpp
@@ -74,8 +74,7 @@ QQmlBoundSignalExpression::QQmlBoundSignalExpression(QObject *target, int index,
 {
     init(ctxt, scope);
 
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine());
-    QV4::ExecutionEngine *v4 = ep->v4engine();
+    QV4::ExecutionEngine *v4 = engine()->handle();
 
     QString function;
 
@@ -123,7 +122,7 @@ QQmlBoundSignalExpression::QQmlBoundSignalExpression(QObject *target, int index,
     // It's important to call init first, because m_index gets remapped in case of cloned signals.
     init(ctxt, scope);
 
-    QV4::ExecutionEngine *engine = QQmlEnginePrivate::getV4Engine(ctxt->engine);
+    QV4::ExecutionEngine *engine = ctxt->engine->handle();
 
     QList<QByteArray> signalParameters = QMetaObjectPrivate::signal(m_target->metaObject(), m_index).parameterNames();
     if (!signalParameters.isEmpty()) {
@@ -182,8 +181,10 @@ void QQmlBoundSignalExpression::evaluate(void **a)
     if (!expressionFunctionValid())
         return;
 
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine());
-    QV4::Scope scope(ep->v4engine());
+    QQmlEngine *qmlengine = engine();
+    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(qmlengine);
+    QV4::ExecutionEngine *v4 = qmlengine->handle();
+    QV4::Scope scope(v4);
 
     ep->referenceScarceResources(); // "hold" scarce resources in memory during evaluation.
 
@@ -215,7 +216,7 @@ void QQmlBoundSignalExpression::evaluate(void **a)
             if (!*reinterpret_cast<void* const *>(a[ii + 1]))
                 jsCall->args[ii] = QV4::Primitive::nullValue();
             else
-                jsCall->args[ii] = QV4::QObjectWrapper::wrap(ep->v4engine(), *reinterpret_cast<QObject* const *>(a[ii + 1]));
+                jsCall->args[ii] = QV4::QObjectWrapper::wrap(v4, *reinterpret_cast<QObject* const *>(a[ii + 1]));
         } else {
             jsCall->args[ii] = scope.engine->fromVariant(QVariant(type, a[ii + 1]));
         }
@@ -233,8 +234,9 @@ void QQmlBoundSignalExpression::evaluate(const QList<QVariant> &args)
     if (!expressionFunctionValid())
         return;
 
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine());
-    QV4::Scope scope(ep->v4engine());
+    QQmlEngine *qmlengine = engine();
+    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(qmlengine);
+    QV4::Scope scope(qmlengine->handle());
 
     ep->referenceScarceResources(); // "hold" scarce resources in memory during evaluation.
 
diff --git a/src/qml/qml/qqmlcomponent.cpp b/src/qml/qml/qqmlcomponent.cpp
index e3dc3be81e..b175223e13 100644
--- a/src/qml/qml/qqmlcomponent.cpp
+++ b/src/qml/qml/qqmlcomponent.cpp
@@ -1436,8 +1436,7 @@ void QQmlComponent::incubateObject(QQmlV4Function *args)
 // XXX used by QSGLoader
 void QQmlComponentPrivate::initializeObjectWithInitialProperties(QV4::QmlContext *qmlContext, const QV4::Value &valuemap, QObject *toCreate)
 {
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
-    QV4::ExecutionEngine *v4engine = QV8Engine::getV4(ep->v8engine());
+    QV4::ExecutionEngine *v4engine = engine->handle();
     QV4::Scope scope(v4engine);
 
     QV4::ScopedValue object(scope, QV4::QObjectWrapper::wrap(v4engine, toCreate));
diff --git a/src/qml/qml/qqmlcontext.cpp b/src/qml/qml/qqmlcontext.cpp
index 9d2e37a2ab..aa1c83d74c 100644
--- a/src/qml/qml/qqmlcontext.cpp
+++ b/src/qml/qml/qqmlcontext.cpp
@@ -837,7 +837,7 @@ const QV4::IdentifierHash &QQmlContextData::propertyNames() const
         if (typeCompilationUnit)
             propertyNameCache = typeCompilationUnit->namedObjectsPerComponent(componentObjectIndex);
         else
-            propertyNameCache = QV4::IdentifierHash(QV8Engine::getV4(engine));
+            propertyNameCache = QV4::IdentifierHash(engine->handle());
     }
     return propertyNameCache;
 }
diff --git a/src/qml/qml/qqmldelayedcallqueue_p.h b/src/qml/qml/qqmldelayedcallqueue_p.h
index b3d361581d..47e211829c 100644
--- a/src/qml/qml/qqmldelayedcallqueue_p.h
+++ b/src/qml/qml/qqmldelayedcallqueue_p.h
@@ -60,7 +60,6 @@
 
 QT_BEGIN_NAMESPACE
 
-class QV8Engine;
 class QQmlDelayedCallQueue : public QObject
 {
     Q_OBJECT
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index a66bcaa9bd..d93aa6b9b6 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -2080,7 +2080,7 @@ void QQmlEnginePrivate::cleanupScarceResources()
     // note that the actual SRD is owned by the JS engine,
     // so we cannot delete the SRD; but we can free the
     // memory used by the variant in the SRD.
-    QV4::ExecutionEngine *engine = QV8Engine::getV4(v8engine());
+    QV4::ExecutionEngine *engine = v4engine();
     while (QV4::ExecutionEngine::ScarceResourceData *sr = engine->scarceResources.first()) {
         sr->data = QVariant();
         engine->scarceResources.remove(sr);
diff --git a/src/qml/qml/qqmlengine_p.h b/src/qml/qml/qqmlengine_p.h
index 74e232fd84..f12409ed9a 100644
--- a/src/qml/qml/qqmlengine_p.h
+++ b/src/qml/qml/qqmlengine_p.h
@@ -150,8 +150,8 @@ public:
     QQmlDelayedError *erroredBindings;
     int inProgressCreations;
 
-    QV8Engine *v8engine() const { return q_func()->handle(); }
-    QV4::ExecutionEngine *v4engine() const { return QV8Engine::getV4(q_func()->handle()); }
+    QV8Engine *v8engine() const { return q_func()->handle()->v8Engine; }
+    QV4::ExecutionEngine *v4engine() const { return q_func()->handle(); }
 
     QQuickWorkerScriptEngine *getWorkerScriptEngine();
     QQuickWorkerScriptEngine *workerScriptEngine;
@@ -295,7 +295,7 @@ inline void QQmlEnginePrivate::dereferenceScarceResources()
     // expression must have completed.  We can safely release the
     // scarce resources.
     if (Q_LIKELY(scarceResourcesRefCount == 0)) {
-        QV4::ExecutionEngine *engine = QV8Engine::getV4(v8engine());
+        QV4::ExecutionEngine *engine = v4engine();
         if (Q_UNLIKELY(!engine->scarceResources.isEmpty())) {
             cleanupScarceResources();
         }
@@ -385,14 +385,14 @@ QV8Engine *QQmlEnginePrivate::getV8Engine(QQmlEngine *e)
 {
     Q_ASSERT(e);
 
-    return e->d_func()->v8engine();
+    return e->handle()->v8Engine;
 }
 
 QV4::ExecutionEngine *QQmlEnginePrivate::getV4Engine(QQmlEngine *e)
 {
     Q_ASSERT(e);
 
-    return e->d_func()->v4engine();
+    return e->handle();
 }
 
 QQmlEnginePrivate *QQmlEnginePrivate::get(QQmlEngine *e)
@@ -428,9 +428,7 @@ QQmlEngine *QQmlEnginePrivate::get(QQmlEnginePrivate *p)
 
 QQmlEnginePrivate *QQmlEnginePrivate::get(QV4::ExecutionEngine *e)
 {
-    if (!e->v8Engine)
-        return 0;
-    QQmlEngine *qmlEngine = e->v8Engine->engine();
+    QQmlEngine *qmlEngine = e->qmlEngine();
     if (!qmlEngine)
         return 0;
     return get(qmlEngine);
diff --git a/src/qml/qml/qqmlexpression.cpp b/src/qml/qml/qqmlexpression.cpp
index 35dbaccbbe..3ba0afc7bd 100644
--- a/src/qml/qml/qqmlexpression.cpp
+++ b/src/qml/qml/qqmlexpression.cpp
@@ -74,7 +74,7 @@ void QQmlExpressionPrivate::init(QQmlContextData *ctxt, const QString &expr, QOb
 void QQmlExpressionPrivate::init(QQmlContextData *ctxt, QV4::Function *runtimeFunction, QObject *me)
 {
     expressionFunctionValid = true;
-    QV4::ExecutionEngine *engine = QQmlEnginePrivate::getV4Engine(ctxt->engine);
+    QV4::ExecutionEngine *engine = ctxt->engine->handle();
     QV4::Scope scope(engine);
     QV4::Scoped<QV4::QmlContext> qmlContext(scope, QV4::QmlContext::create(engine->rootContext(), ctxt, me));
     setupFunction(qmlContext, runtimeFunction);
@@ -266,13 +266,14 @@ QVariant QQmlExpressionPrivate::value(bool *isUndefined)
         return QVariant();
     }
 
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(q->engine());
+    QQmlEngine *engine = q->engine();
+    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
     QVariant rv;
 
     ep->referenceScarceResources(); // "hold" scarce resources in memory during evaluation.
 
     {
-        QV4::Scope scope(QV8Engine::getV4(ep->v8engine()));
+        QV4::Scope scope(engine->handle());
         QV4::ScopedValue result(scope, v4value(isUndefined));
         if (!hasError())
             rv = scope.engine->toVariant(result, -1);
diff --git a/src/qml/qml/qqmljavascriptexpression.cpp b/src/qml/qml/qqmljavascriptexpression.cpp
index 006611e089..cd35ab93c6 100644
--- a/src/qml/qml/qqmljavascriptexpression.cpp
+++ b/src/qml/qml/qqmljavascriptexpression.cpp
@@ -183,7 +183,7 @@ void QQmlJavaScriptExpression::refresh()
 
 QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(bool *isUndefined)
 {
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(m_context->engine);
+    QV4::ExecutionEngine *v4 = m_context->engine->handle();
     QV4::Scope scope(v4);
     QV4::JSCallData jsCall(scope);
 
@@ -217,7 +217,7 @@ QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(QV4::CallData *callData, b
     if (notifyOnValueChanged())
         capture.guards.copyAndClearPrepend(activeGuards);
 
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(ep->v8engine());
+    QV4::ExecutionEngine *v4 = m_context->engine->handle();
     callData->thisObject = v4->globalObject;
     if (scopeObject()) {
          QV4::ReturnedValue scope = QV4::QObjectWrapper::wrap(v4, scopeObject());
@@ -414,7 +414,7 @@ QQmlJavaScriptExpression::evalFunction(QQmlContextData *ctxt, QObject *scopeObje
     QQmlEngine *engine = ctxt->engine;
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
 
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(ep->v8engine());
+    QV4::ExecutionEngine *v4 = engine->handle();
     QV4::Scope scope(v4);
 
     QV4::Scoped<QV4::QmlContext> qmlContext(scope, QV4::QmlContext::create(v4->rootContext(), ctxt, scopeObject));
@@ -444,7 +444,7 @@ void QQmlJavaScriptExpression::createQmlBinding(QQmlContextData *ctxt, QObject *
     QQmlEngine *engine = ctxt->engine;
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
 
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(ep->v8engine());
+    QV4::ExecutionEngine *v4 = engine->handle();
     QV4::Scope scope(v4);
 
     QV4::Scoped<QV4::QmlContext> qmlContext(scope, QV4::QmlContext::create(v4->rootContext(), ctxt, qmlScope));
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index 8d17ae3233..1c3e24fe02 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -114,7 +114,7 @@ void QQmlObjectCreator::init(QQmlContextData *providedParentContext)
 {
     parentContext = providedParentContext;
     engine = parentContext->engine;
-    v4 = QV8Engine::getV4(engine);
+    v4 = engine->handle();
 
     if (compilationUnit && !compilationUnit->engine)
         compilationUnit->linkToEngine(v4);
@@ -1024,7 +1024,7 @@ bool QQmlObjectCreator::setPropertyBinding(const QQmlPropertyData *property, con
         } else if (property->propType() == QMetaType::QVariant) {
             if (property->isVarProperty()) {
                 QV4::Scope scope(v4);
-                QV4::ScopedValue wrappedObject(scope, QV4::QObjectWrapper::wrap(QV8Engine::getV4(engine), createdSubObject));
+                QV4::ScopedValue wrappedObject(scope, QV4::QObjectWrapper::wrap(engine->handle(), createdSubObject));
                 _vmeMetaObject->setVMEProperty(property->coreIndex(), wrappedObject);
             } else {
                 QVariant value = QVariant::fromValue(createdSubObject);
diff --git a/src/qml/qml/qqmltypeloader.cpp b/src/qml/qml/qqmltypeloader.cpp
index fab5cf6c1f..2afcf1da3e 100644
--- a/src/qml/qml/qqmltypeloader.cpp
+++ b/src/qml/qml/qqmltypeloader.cpp
@@ -1524,7 +1524,7 @@ void QQmlTypeLoader::Blob::dependencyComplete(QQmlDataBlob *blob)
 
 bool QQmlTypeLoader::Blob::isDebugging() const
 {
-    return QV8Engine::getV4(typeLoader()->engine())->debugger() != 0;
+    return typeLoader()->engine()->handle()->debugger() != 0;
 }
 
 bool QQmlTypeLoader::Blob::qmldirDataAvailable(QQmlQmldirData *data, QList<QQmlError> *errors)
@@ -2097,7 +2097,7 @@ bool QQmlTypeData::tryLoadFromDiskCache()
     if (isDebugging())
         return false;
 
-    QV4::ExecutionEngine *v4 = QQmlEnginePrivate::getV4Engine(typeLoader()->engine());
+    QV4::ExecutionEngine *v4 = typeLoader()->engine()->handle();
     if (!v4)
         return false;
 
@@ -2440,7 +2440,7 @@ bool QQmlTypeData::loadFromSource()
     m_document.reset(new QmlIR::Document(isDebugging()));
     m_document->jsModule.sourceTimeStamp = m_backupSourceCode.sourceTimeStamp();
     QQmlEngine *qmlEngine = typeLoader()->engine();
-    QmlIR::IRBuilder compiler(QV8Engine::get(qmlEngine)->illegalNames());
+    QmlIR::IRBuilder compiler(qmlEngine->handle()->v8Engine->illegalNames());
 
     QString sourceError;
     const QString source = m_backupSourceCode.readAll(&sourceError);
@@ -2828,9 +2828,7 @@ void QQmlScriptData::initialize(QQmlEngine *engine)
     Q_ASSERT(engine);
     Q_ASSERT(!hasEngine());
 
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
-    QV8Engine *v8engine = ep->v8engine();
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(v8engine);
+    QV4::ExecutionEngine *v4 = engine->handle();
 
     m_program = new QV4::Script(v4, 0, m_precompiledScript);
 
@@ -2846,7 +2844,7 @@ QV4::ReturnedValue QQmlScriptData::scriptValueForContext(QQmlContextData *parent
 
     Q_ASSERT(parentCtxt && parentCtxt->engine);
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(parentCtxt->engine);
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(parentCtxt->engine);
+    QV4::ExecutionEngine *v4 = parentCtxt->engine->handle();
     QV4::Scope scope(v4);
 
     bool shared = m_precompiledScript->data->flags & QV4::CompiledData::Unit::IsSharedLibrary;
diff --git a/src/qml/qml/qqmlvmemetaobject.cpp b/src/qml/qml/qqmlvmemetaobject.cpp
index 281d64ac79..73cb20dc7f 100644
--- a/src/qml/qml/qqmlvmemetaobject.cpp
+++ b/src/qml/qml/qqmlvmemetaobject.cpp
@@ -926,12 +926,14 @@ int QQmlVMEMetaObject::metaCall(QObject *o, QMetaObject::Call c, int _id, void *
             id -= plainSignals;
 
             if (id < methodCount) {
-                if (!ctxt->engine)
+                QQmlEngine *engine = ctxt->engine;
+                if (!engine)
                     return -1; // We can't run the method
 
-                QQmlEnginePrivate *ep = QQmlEnginePrivate::get(ctxt->engine);
+                QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine);
+                QV4::ExecutionEngine *v4 = engine->handle();
                 ep->referenceScarceResources(); // "hold" scarce resources in memory during evaluation.
-                QV4::Scope scope(ep->v4engine());
+                QV4::Scope scope(v4);
 
 
                 QV4::ScopedFunctionObject function(scope, method(id));
@@ -951,7 +953,7 @@ int QQmlVMEMetaObject::metaCall(QObject *o, QMetaObject::Call c, int _id, void *
 
                 const unsigned int parameterCount = function->formalParameterCount();
                 QV4::JSCallData jsCallData(scope, parameterCount);
-                *jsCallData->thisObject = ep->v8engine()->global();
+                *jsCallData->thisObject = v4->global();
 
                 for (uint ii = 0; ii < parameterCount; ++ii)
                     jsCallData->args[ii] = scope.engine->fromVariant(*(QVariant *)a[ii + 1]);
diff --git a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
index f2b396ad00..44ad174f37 100644
--- a/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
+++ b/src/qml/qml/v8/qqmlbuiltinfunctions.cpp
@@ -1116,8 +1116,7 @@ ReturnedValue QtObject::method_createQmlObject(const FunctionObject *b, const Va
         }
     };
 
-    QV8Engine *v8engine = scope.engine->v8Engine;
-    QQmlEngine *engine = v8engine->engine();
+    QQmlEngine *engine = scope.engine->qmlEngine();
 
     QQmlContextData *context = scope.engine->callingQmlContext();
     Q_ASSERT(context);
@@ -1244,8 +1243,7 @@ ReturnedValue QtObject::method_createComponent(const FunctionObject *b, const Va
     if (argc < 1 || argc > 3)
         THROW_GENERIC_ERROR("Qt.createComponent(): Invalid arguments");
 
-    QV8Engine *v8engine = scope.engine->v8Engine;
-    QQmlEngine *engine = v8engine->engine();
+    QQmlEngine *engine = scope.engine->qmlEngine();
 
     QQmlContextData *context = scope.engine->callingQmlContext();
     Q_ASSERT(context);
diff --git a/src/qml/qml/v8/qv8engine.cpp b/src/qml/qml/v8/qv8engine.cpp
index 2947f7870a..2bf623f144 100644
--- a/src/qml/qml/v8/qv8engine.cpp
+++ b/src/qml/qml/v8/qv8engine.cpp
@@ -123,9 +123,10 @@ static void restoreJSValue(QDataStream &stream, void *data)
     }
 }
 
-QV8Engine::QV8Engine(QJSEngine* qq)
+QV8Engine::QV8Engine(QJSEngine *qq, QV4::ExecutionEngine *v4)
     : q(qq)
     , m_engine(0)
+    , m_v4Engine(v4)
     , m_xmlHttpRequestData(0)
 {
 #ifdef Q_PROCESSOR_X86_32
@@ -146,8 +147,6 @@ QV8Engine::QV8Engine(QJSEngine* qq)
         QMetaType::registerConverter<QJSValue, QStringList>(convertJSValueToVariantType<QStringList>);
     QMetaType::registerStreamOperators(qMetaTypeId<QJSValue>(), saveJSValue, restoreJSValue);
 
-    m_v4Engine = new QV4::ExecutionEngine;
-    m_v4Engine->v8Engine = this;
     m_delayedCallQueue.init(m_v4Engine);
 
     QV4::QObjectWrapper::initializeBindings(m_v4Engine);
@@ -162,8 +161,6 @@ QV8Engine::~QV8Engine()
     qt_rem_qmlxmlhttprequest(m_v4Engine, m_xmlHttpRequestData);
     m_xmlHttpRequestData = 0;
 #endif
-
-    delete m_v4Engine;
 }
 
 #if QT_CONFIG(qml_network)
@@ -288,11 +285,6 @@ void QV8Engine::setEngine(QQmlEngine *engine)
     initQmlGlobalObject();
 }
 
-QV4::ReturnedValue QV8Engine::global()
-{
-    return m_v4Engine->globalObject->asReturnedValue();
-}
-
 void QV8Engine::startTimer(const QString &timerName)
 {
     if (!m_time.isValid())
diff --git a/src/qml/qml/v8/qv8engine_p.h b/src/qml/qml/v8/qv8engine_p.h
index 98b182147c..eb2b8b474c 100644
--- a/src/qml/qml/v8/qv8engine_p.h
+++ b/src/qml/qml/v8/qv8engine_p.h
@@ -153,12 +153,11 @@ class Q_QML_PRIVATE_EXPORT QV8Engine
 {
     friend class QJSEngine;
 public:
-    static QV8Engine* get(QJSEngine* q) { Q_ASSERT(q); return q->handle(); }
 //    static QJSEngine* get(QV8Engine* d) { Q_ASSERT(d); return d->q; }
-    static QV4::ExecutionEngine *getV4(QJSEngine *q) { return q->handle()->m_v4Engine; }
+    static QV4::ExecutionEngine *getV4(QJSEngine *q) { return q->handle(); }
     static QV4::ExecutionEngine *getV4(QV8Engine *d) { return d->m_v4Engine; }
 
-    QV8Engine(QJSEngine* qq);
+    QV8Engine(QJSEngine* qq, QV4::ExecutionEngine *v4);
     virtual ~QV8Engine();
 
     // This enum should be in sync with QQmlEngine::ObjectOwnership
@@ -172,7 +171,6 @@ public:
     void setEngine(QQmlEngine *engine);
     QQmlEngine *engine() { return m_engine; }
     QJSEngine *publicEngine() { return q; }
-    QV4::ReturnedValue global();
     QQmlDelayedCallQueue *delayedCallQueue() { return &m_delayedCallQueue; }
 
     void *xmlHttpRequestData() const { return m_xmlHttpRequestData; }
diff --git a/src/qml/types/qqmldelegatemodel.cpp b/src/qml/types/qqmldelegatemodel.cpp
index fa1be563b5..0e2de0da7a 100644
--- a/src/qml/types/qqmldelegatemodel.cpp
+++ b/src/qml/types/qqmldelegatemodel.cpp
@@ -128,7 +128,8 @@ public:
     QQmlDelegateModelEngineData(QV4::ExecutionEngine *v4);
     ~QQmlDelegateModelEngineData();
 
-    QV4::ReturnedValue array(QV8Engine *engine, const QVector<QQmlChangeSet::Change> &changes);
+    QV4::ReturnedValue array(QV4::ExecutionEngine *engine,
+                             const QVector<QQmlChangeSet::Change> &changes);
 
     QV4::PersistentValue changeProto;
 };
@@ -325,7 +326,7 @@ void QQmlDelegateModel::componentComplete()
     }
 
     d->m_cacheMetaType = new QQmlDelegateModelItemMetaType(
-            QQmlEnginePrivate::getV8Engine(d->m_context->engine()), this, groupNames);
+                d->m_context->engine()->handle(), this, groupNames);
 
     d->m_compositor.setGroupCount(d->m_groupCount);
     d->m_compositor.setDefaultGroups(defaultGroups);
@@ -1481,7 +1482,7 @@ void QQmlDelegateModelPrivate::emitChanges()
         return;
 
     m_transaction = true;
-    QV8Engine *engine = QQmlEnginePrivate::getV8Engine(m_context->engine());
+    QV4::ExecutionEngine *engine = m_context->engine()->handle();
     for (int i = 1; i < m_groupCount; ++i)
         QQmlDelegateModelGroupPrivate::get(m_groups[i])->emitChanges(engine);
     m_transaction = false;
@@ -1676,10 +1677,10 @@ bool QQmlDelegateModelPrivate::insert(Compositor::insert_iterator &before, const
 //============================================================================
 
 QQmlDelegateModelItemMetaType::QQmlDelegateModelItemMetaType(
-        QV8Engine *engine, QQmlDelegateModel *model, const QStringList &groupNames)
+        QV4::ExecutionEngine *engine, QQmlDelegateModel *model, const QStringList &groupNames)
     : model(model)
     , groupCount(groupNames.count() + 1)
-    , v8Engine(engine)
+    , v4Engine(engine)
     , metaObject(0)
     , groupNames(groupNames)
 {
@@ -1720,37 +1721,36 @@ void QQmlDelegateModelItemMetaType::initializeMetaObject()
 
 void QQmlDelegateModelItemMetaType::initializePrototype()
 {
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(v8Engine);
-    QV4::Scope scope(v4);
+    QV4::Scope scope(v4Engine);
 
-    QV4::ScopedObject proto(scope, v4->newObject());
+    QV4::ScopedObject proto(scope, v4Engine->newObject());
     proto->defineAccessorProperty(QStringLiteral("model"), QQmlDelegateModelItem::get_model, 0);
     proto->defineAccessorProperty(QStringLiteral("groups"), QQmlDelegateModelItem::get_groups, QQmlDelegateModelItem::set_groups);
     QV4::ScopedString s(scope);
     QV4::ScopedProperty p(scope);
 
-    s = v4->newString(QStringLiteral("isUnresolved"));
+    s = v4Engine->newString(QStringLiteral("isUnresolved"));
     QV4::ScopedFunctionObject f(scope);
     QV4::ExecutionContext *global = scope.engine->rootContext();
     p->setGetter((f = QV4::DelegateModelGroupFunction::create(global, 30, QQmlDelegateModelItem::get_member)));
     p->setSetter(0);
     proto->insertMember(s, p, QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
 
-    s = v4->newString(QStringLiteral("inItems"));
+    s = v4Engine->newString(QStringLiteral("inItems"));
     p->setGetter((f = QV4::DelegateModelGroupFunction::create(global, QQmlListCompositor::Default, QQmlDelegateModelItem::get_member)));
     p->setSetter((f = QV4::DelegateModelGroupFunction::create(global, QQmlListCompositor::Default, QQmlDelegateModelItem::set_member)));
     proto->insertMember(s, p, QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
 
-    s = v4->newString(QStringLiteral("inPersistedItems"));
+    s = v4Engine->newString(QStringLiteral("inPersistedItems"));
     p->setGetter((f = QV4::DelegateModelGroupFunction::create(global, QQmlListCompositor::Persisted, QQmlDelegateModelItem::get_member)));
     p->setSetter((f = QV4::DelegateModelGroupFunction::create(global, QQmlListCompositor::Persisted, QQmlDelegateModelItem::set_member)));
     proto->insertMember(s, p, QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
 
-    s = v4->newString(QStringLiteral("itemsIndex"));
+    s = v4Engine->newString(QStringLiteral("itemsIndex"));
     p->setGetter((f = QV4::DelegateModelGroupFunction::create(global, QQmlListCompositor::Default, QQmlDelegateModelItem::get_index)));
     proto->insertMember(s, p, QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
 
-    s = v4->newString(QStringLiteral("persistedItemsIndex"));
+    s = v4Engine->newString(QStringLiteral("persistedItemsIndex"));
     p->setGetter((f = QV4::DelegateModelGroupFunction::create(global, QQmlListCompositor::Persisted, QQmlDelegateModelItem::get_index)));
     p->setSetter(0);
     proto->insertMember(s, p, QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
@@ -1758,19 +1758,19 @@ void QQmlDelegateModelItemMetaType::initializePrototype()
     for (int i = 2; i < groupNames.count(); ++i) {
         QString propertyName = QLatin1String("in") + groupNames.at(i);
         propertyName.replace(2, 1, propertyName.at(2).toUpper());
-        s = v4->newString(propertyName);
+        s = v4Engine->newString(propertyName);
         p->setGetter((f = QV4::DelegateModelGroupFunction::create(global, i + 1, QQmlDelegateModelItem::get_member)));
         p->setSetter((f = QV4::DelegateModelGroupFunction::create(global, i + 1, QQmlDelegateModelItem::set_member)));
         proto->insertMember(s, p, QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
     }
     for (int i = 2; i < groupNames.count(); ++i) {
         const QString propertyName = groupNames.at(i) + QLatin1String("Index");
-        s = v4->newString(propertyName);
+        s = v4Engine->newString(propertyName);
         p->setGetter((f = QV4::DelegateModelGroupFunction::create(global, i + 1, QQmlDelegateModelItem::get_index)));
         p->setSetter(0);
         proto->insertMember(s, p, QV4::Attr_Accessor|QV4::Attr_NotConfigurable|QV4::Attr_NotEnumerable);
     }
-    modelItemProto.set(v4, proto);
+    modelItemProto.set(v4Engine, proto);
 }
 
 int QQmlDelegateModelItemMetaType::parseGroups(const QStringList &groups) const
@@ -1787,7 +1787,7 @@ int QQmlDelegateModelItemMetaType::parseGroups(const QStringList &groups) const
 int QQmlDelegateModelItemMetaType::parseGroups(const QV4::Value &groups) const
 {
     int groupFlags = 0;
-    QV4::Scope scope(QV8Engine::getV4(v8Engine));
+    QV4::Scope scope(v4Engine);
 
     QV4::ScopedString s(scope, groups);
     if (s) {
@@ -1907,7 +1907,7 @@ void QV4::Heap::QQmlDelegateModelItemObject::destroy()
 
 QQmlDelegateModelItem::QQmlDelegateModelItem(
         QQmlDelegateModelItemMetaType *metaType, int modelIndex)
-    : v4(QV8Engine::getV4(metaType->v8Engine))
+    : v4(metaType->v4Engine)
     , metaType(metaType)
     , contextData(0)
     , object(0)
@@ -2245,13 +2245,13 @@ bool QQmlDelegateModelGroupPrivate::isChangedConnected()
     IS_SIGNAL_CONNECTED(q, QQmlDelegateModelGroup, changed, (const QQmlV4Handle &,const QQmlV4Handle &));
 }
 
-void QQmlDelegateModelGroupPrivate::emitChanges(QV8Engine *engine)
+void QQmlDelegateModelGroupPrivate::emitChanges(QV4::ExecutionEngine *v4)
 {
     Q_Q(QQmlDelegateModelGroup);
     if (isChangedConnected() && !changeSet.isEmpty()) {
-        QV4::Scope scope(QV8Engine::getV4(engine));
-        QV4::ScopedValue removed(scope, engineData(scope.engine)->array(engine, changeSet.removes()));
-        QV4::ScopedValue inserted(scope, engineData(scope.engine)->array(engine, changeSet.inserts()));
+        QV4::Scope scope(v4);
+        QV4::ScopedValue removed(scope, engineData(scope.engine)->array(v4, changeSet.removes()));
+        QV4::ScopedValue inserted(scope, engineData(scope.engine)->array(v4, changeSet.inserts()));
         emit q->changed(QQmlV4Handle(removed), QQmlV4Handle(inserted));
     }
     if (changeSet.difference() != 0)
@@ -2480,8 +2480,7 @@ QQmlV4Handle QQmlDelegateModelGroup::get(int index)
 
     if (model->m_cacheMetaType->modelItemProto.isUndefined())
         model->m_cacheMetaType->initializePrototype();
-    QV8Engine *v8 = model->m_cacheMetaType->v8Engine;
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(v8);
+    QV4::ExecutionEngine *v4 = model->m_cacheMetaType->v4Engine;
     QV4::Scope scope(v4);
     QV4::ScopedObject o(scope, v4->memoryManager->allocObject<QQmlDelegateModelItemObject>(cacheItem));
     QV4::ScopedObject p(scope, model->m_cacheMetaType->modelItemProto.value());
@@ -3347,9 +3346,9 @@ QQmlDelegateModelEngineData::~QQmlDelegateModelEngineData()
 {
 }
 
-QV4::ReturnedValue QQmlDelegateModelEngineData::array(QV8Engine *engine, const QVector<QQmlChangeSet::Change> &changes)
+QV4::ReturnedValue QQmlDelegateModelEngineData::array(QV4::ExecutionEngine *v4,
+                                                      const QVector<QQmlChangeSet::Change> &changes)
 {
-    QV4::ExecutionEngine *v4 = QV8Engine::getV4(engine);
     QV4::Scope scope(v4);
     QV4::ScopedObject o(scope, QQmlDelegateModelGroupChangeArray::create(v4, changes));
     return o.asReturnedValue();
diff --git a/src/qml/types/qqmldelegatemodel_p_p.h b/src/qml/types/qqmldelegatemodel_p_p.h
index 537937df57..7b60bcddc0 100644
--- a/src/qml/types/qqmldelegatemodel_p_p.h
+++ b/src/qml/types/qqmldelegatemodel_p_p.h
@@ -69,7 +69,7 @@ class QQmlDelegateModelAttachedMetaObject;
 class QQmlDelegateModelItemMetaType : public QQmlRefCount
 {
 public:
-    QQmlDelegateModelItemMetaType(QV8Engine *engine, QQmlDelegateModel *model, const QStringList &groupNames);
+    QQmlDelegateModelItemMetaType(QV4::ExecutionEngine *engine, QQmlDelegateModel *model, const QStringList &groupNames);
     ~QQmlDelegateModelItemMetaType();
 
     void initializeMetaObject();
@@ -80,7 +80,7 @@ public:
 
     QPointer<QQmlDelegateModel> model;
     const int groupCount;
-    QV8Engine * const v8Engine;
+    QV4::ExecutionEngine * const v4Engine;
     QQmlDelegateModelAttachedMetaObject *metaObject;
     const QStringList groupNames;
     QV4::PersistentValue modelItemProto;
@@ -220,7 +220,7 @@ public:
 
     void setModel(QQmlDelegateModel *model, Compositor::Group group);
     bool isChangedConnected();
-    void emitChanges(QV8Engine *engine);
+    void emitChanges(QV4::ExecutionEngine *engine);
     void emitModelUpdated(bool reset);
 
     void createdPackage(int index, QQuickPackage *package);
diff --git a/src/qml/types/qqmllistmodel.cpp b/src/qml/types/qqmllistmodel.cpp
index 3e477edc07..299de8de70 100644
--- a/src/qml/types/qqmllistmodel.cpp
+++ b/src/qml/types/qqmllistmodel.cpp
@@ -1865,7 +1865,7 @@ QQmlListModel *QQmlListModel::createWithOwner(QQmlListModel *newOwner)
 QV4::ExecutionEngine *QQmlListModel::engine() const
 {
     if (m_engine == 0) {
-        m_engine  = QQmlEnginePrivate::get(qmlEngine(this))->v4engine();
+        m_engine  = qmlEngine(this)->handle();
     }
 
     return m_engine;
@@ -2682,7 +2682,7 @@ void QQmlListModelParser::applyBindings(QObject *obj, QV4::CompiledData::Compila
 {
     QQmlListModel *rv = static_cast<QQmlListModel *>(obj);
 
-    rv->m_engine = QV8Engine::getV4(qmlEngine(rv));
+    rv->m_engine = qmlEngine(rv)->handle();
 
     const QV4::CompiledData::Unit *qmlUnit = compilationUnit->data;
 
diff --git a/src/qml/types/qquickworkerscript.cpp b/src/qml/types/qquickworkerscript.cpp
index 231c0fa810..32c0c86ff6 100644
--- a/src/qml/types/qquickworkerscript.cpp
+++ b/src/qml/types/qquickworkerscript.cpp
@@ -201,7 +201,7 @@ private:
 };
 
 QQuickWorkerScriptEnginePrivate::WorkerEngine::WorkerEngine(QQuickWorkerScriptEnginePrivate *parent)
-: QV8Engine(0), p(parent)
+    : QV8Engine(nullptr, new QV4::ExecutionEngine), p(parent)
 #if QT_CONFIG(qml_network)
 , accessManager(0)
 #endif
@@ -214,6 +214,7 @@ QQuickWorkerScriptEnginePrivate::WorkerEngine::~WorkerEngine()
 #if QT_CONFIG(qml_network)
     delete accessManager;
 #endif
+    delete m_v4Engine;
 }
 
 void QQuickWorkerScriptEnginePrivate::WorkerEngine::init()
@@ -250,7 +251,7 @@ void QQuickWorkerScriptEnginePrivate::WorkerEngine::init()
                                                                                 QQuickWorkerScriptEnginePrivate::method_sendMessage));
     QV4::JSCallData jsCallData(scope, 1);
     jsCallData->args[0] = function;
-    *jsCallData->thisObject = global();
+    *jsCallData->thisObject = m_v4Engine->global();
     createsend.set(scope.engine, createsendconstructor->call(jsCallData));
 }
 
@@ -267,7 +268,7 @@ QV4::ReturnedValue QQuickWorkerScriptEnginePrivate::WorkerEngine::sendFunction(i
     QV4::ScopedValue v(scope);
     QV4::JSCallData jsCallData(scope, 1);
     jsCallData->args[0] = QV4::Primitive::fromInt32(id);
-    *jsCallData->thisObject = global();
+    *jsCallData->thisObject = m_v4Engine->global();
     v = f->call(jsCallData);
     if (scope.hasException())
         v = scope.engine->catchException();
@@ -367,7 +368,7 @@ void QQuickWorkerScriptEnginePrivate::processMessage(int id, const QByteArray &d
     Q_ASSERT(!!qmlContext);
 
     QV4::JSCallData jsCallData(scope, 2);
-    *jsCallData->thisObject = workerEngine->global();
+    *jsCallData->thisObject = v4->global();
     jsCallData->args[0] = qmlContext->d()->qml(); // ###
     jsCallData->args[1] = value;
     f->call(jsCallData);
@@ -730,8 +731,7 @@ bool QQuickWorkerScript::event(QEvent *event)
         QQmlEngine *engine = qmlEngine(this);
         if (engine) {
             WorkerDataEvent *workerEvent = static_cast<WorkerDataEvent *>(event);
-            QV8Engine *v8engine = QQmlEnginePrivate::get(engine)->v8engine();
-            QV4::Scope scope(QV8Engine::getV4(v8engine));
+            QV4::Scope scope(engine->handle());
             QV4::ScopedValue value(scope, QV4::Serialize::deserialize(workerEvent->data(), scope.engine));
             emit message(QQmlV4Handle(value));
         }