Merge remote-tracking branch 'origin/5.7' into dev

Change-Id: I57b06e2e98beb010a56dd0593d93e078ecf76eea

115 files changed, 1855 insertions, 1433 deletions

diff --git a/src/3rdparty/masm/stubs/ExecutableAllocator.h b/src/3rdparty/masm/stubs/ExecutableAllocator.h
index fe8fc66b03..5a3939b7b2 100644
--- a/src/3rdparty/masm/stubs/ExecutableAllocator.h
+++ b/src/3rdparty/masm/stubs/ExecutableAllocator.h
@@ -57,6 +57,10 @@
 #include <unistd.h>
 #endif
 
+#ifdef __QNXNTO__
+using std::perror;
+#endif
+
 namespace JSC {
 
 class JSGlobalData;
diff --git a/src/3rdparty/masm/stubs/wtf/PassOwnPtr.h b/src/3rdparty/masm/stubs/wtf/PassOwnPtr.h
index 21436b0bec..0e18132f77 100644
--- a/src/3rdparty/masm/stubs/wtf/PassOwnPtr.h
+++ b/src/3rdparty/masm/stubs/wtf/PassOwnPtr.h
@@ -101,8 +101,8 @@ public:
 private:
     template <typename PtrType> friend PassOwnPtr<PtrType> adoptPtr(PtrType*);
 
-    PassOwnPtr<T>& operator=(const PassOwnPtr<T>&)
-    {}
+    PassOwnPtr<T>& operator=(const PassOwnPtr<T>& t);
+
     mutable QScopedPointer<T> m_ptr;
 };
 
diff --git a/src/3rdparty/masm/stubs/wtf/PassRefPtr.h b/src/3rdparty/masm/stubs/wtf/PassRefPtr.h
index 1a837464fa..f072e70dd7 100644
--- a/src/3rdparty/masm/stubs/wtf/PassRefPtr.h
+++ b/src/3rdparty/masm/stubs/wtf/PassRefPtr.h
@@ -81,8 +81,7 @@ public:
     }
 
 private:
-    PassRefPtr<T>& operator=(const PassRefPtr<T>&)
-    {}
+    PassRefPtr<T>& operator=(const PassRefPtr<T>& t);
 
     template <typename PtrType> friend PassRefPtr<PtrType> adoptRef(PtrType*);
     mutable T* m_ptr;
diff --git a/src/imports/testlib/SignalSpy.qml b/src/imports/testlib/SignalSpy.qml
index 7288c57ea0..200fc725f7 100644
--- a/src/imports/testlib/SignalSpy.qml
+++ b/src/imports/testlib/SignalSpy.qml
@@ -222,14 +222,16 @@ Item {
     /*! \internal */
     function qtest_update() {
         if (qtest_prevTarget != null) {
-            var prevFunc = qtest_prevTarget[qtest_prevSignalName]
+            var prevHandlerName = qtest_signalHandlerName(qtest_prevSignalName)
+            var prevFunc = qtest_prevTarget[prevHandlerName]
             if (prevFunc)
                 prevFunc.disconnect(spy.qtest_activated)
             qtest_prevTarget = null
             qtest_prevSignalName = ""
         }
         if (target != null && signalName != "") {
-            var func = target[signalName]
+            var handlerName = qtest_signalHandlerName(signalName)
+            var func = target[handlerName]
             if (func === undefined) {
                 spy.qtest_valid = false
                 console.log("Signal '" + signalName + "' not found")
@@ -250,4 +252,11 @@ Item {
         ++qtest_count
         spy.qtest_signalArguments[spy.qtest_signalArguments.length] = arguments
     }
+
+    /*! \internal */
+    function qtest_signalHandlerName(sn) {
+        if (sn.substr(0, 2) === "on" && sn[2] === sn[2].toUpperCase())
+            return sn
+        return "on" + sn.substr(0, 1).toUpperCase() + sn.substr(1)
+    }
 }
diff --git a/src/particles/qquickage.cpp b/src/particles/qquickage.cpp
index 9867e7e0ed..578207531d 100644
--- a/src/particles/qquickage.cpp
+++ b/src/particles/qquickage.cpp
@@ -88,23 +88,23 @@ QQuickAgeAffector::QQuickAgeAffector(QQuickItem *parent) :
 bool QQuickAgeAffector::affectParticle(QQuickParticleData *d, qreal dt)
 {
     Q_UNUSED(dt);
-    if (d->stillAlive()){
-        qreal curT = (qreal)m_system->timeInt/1000.0;
-        qreal ttl = (qreal)m_lifeLeft/1000.0;
+    if (d->stillAlive(m_system)){
+        float curT = m_system->timeInt / 1000.0f;
+        float ttl = m_lifeLeft / 1000.0f;
         if (!m_advancePosition && ttl > 0){
-            qreal x = d->curX();
-            qreal vx = d->curVX();
-            qreal ax = d->curAX();
-            qreal y = d->curY();
-            qreal vy = d->curVY();
-            qreal ay = d->curAY();
+            float x = d->curX(m_system);
+            float vx = d->curVX(m_system);
+            float ax = d->curAX();
+            float y = d->curY(m_system);
+            float vy = d->curVY(m_system);
+            float ay = d->curAY();
             d->t = curT - (d->lifeSpan - ttl);
-            d->setInstantaneousX(x);
-            d->setInstantaneousVX(vx);
-            d->setInstantaneousAX(ax);
-            d->setInstantaneousY(y);
-            d->setInstantaneousVY(vy);
-            d->setInstantaneousAY(ay);
+            d->setInstantaneousX(x, m_system);
+            d->setInstantaneousVX(vx, m_system);
+            d->setInstantaneousAX(ax, m_system);
+            d->setInstantaneousY(y, m_system);
+            d->setInstantaneousVY(vy, m_system);
+            d->setInstantaneousAY(ay, m_system);
         } else {
             d->t = curT - (d->lifeSpan - ttl);
         }
diff --git a/src/particles/qquickcustomaffector.cpp b/src/particles/qquickcustomaffector.cpp
index 55310f92d5..b95810bb62 100644
--- a/src/particles/qquickcustomaffector.cpp
+++ b/src/particles/qquickcustomaffector.cpp
@@ -122,11 +122,15 @@ void QQuickCustomAffector::affectSystem(qreal dt)
     updateOffsets();
 
     QList<QQuickParticleData*> toAffect;
-    foreach (QQuickParticleGroupData* gd, m_system->groupData)
-        if (activeGroup(m_system->groupData.key(gd)))
-            foreach (QQuickParticleData* d, gd->data)
-                if (shouldAffect(d))
+    foreach (QQuickParticleGroupData* gd, m_system->groupData) {
+        if (activeGroup(gd->index)) {
+            foreach (QQuickParticleData* d, gd->data) {
+                if (shouldAffect(d)) {
                     toAffect << d;
+                }
+            }
+        }
+    }
 
     if (toAffect.isEmpty())
         return;
@@ -134,8 +138,8 @@ void QQuickCustomAffector::affectSystem(qreal dt)
     if (justAffected) {
         foreach (QQuickParticleData* d, toAffect) {//Not postAffect to avoid saying the particle changed
             if (m_onceOff)
-                m_onceOffed << qMakePair(d->group, d->index);
-            emit affected(d->curX(), d->curY());
+                m_onceOffed << qMakePair(d->groupId, d->index);
+            emit affected(d->curX(m_system), d->curY(m_system));
         }
         return;
     }
@@ -150,7 +154,7 @@ void QQuickCustomAffector::affectSystem(qreal dt)
     QV4::ScopedArrayObject array(scope, v4->newArrayObject(toAffect.size()));
     QV4::ScopedValue v(scope);
     for (int i=0; i<toAffect.size(); i++)
-        array->putIndexed(i, (v = toAffect[i]->v4Value()));
+        array->putIndexed(i, (v = toAffect[i]->v4Value(m_system)));
 
     if (dt >= simulationCutoff || dt <= simulationDelta) {
         affectProperties(toAffect, dt);
@@ -180,7 +184,7 @@ bool QQuickCustomAffector::affectParticle(QQuickParticleData *d, qreal dt)
 {
     //This does the property based affecting, called by superclass if signal isn't hooked up.
     bool changed = false;
-    QPointF curPos(d->curX(), d->curY());
+    QPointF curPos(d->curX(m_system), d->curY(m_system));
 
     if (m_acceleration != &m_nullVector){
         QPointF pos = m_acceleration->sample(curPos);
@@ -190,22 +194,22 @@ bool QQuickCustomAffector::affectParticle(QQuickParticleData *d, qreal dt)
             pos += curAcc;
         }
         if (pos != curAcc) {
-            d->setInstantaneousAX(pos.x());
-            d->setInstantaneousAY(pos.y());
+            d->setInstantaneousAX(pos.x(), m_system);
+            d->setInstantaneousAY(pos.y(), m_system);
             changed = true;
         }
     }
 
     if (m_velocity != &m_nullVector){
         QPointF pos = m_velocity->sample(curPos);
-        QPointF curVel = QPointF(d->curVX(), d->curVY());
+        QPointF curVel = QPointF(d->curVX(m_system), d->curVY(m_system));
         if (m_relative) {
             pos *= dt;
             pos += curVel;
         }
         if (pos != curVel) {
-            d->setInstantaneousVX(pos.x());
-            d->setInstantaneousVY(pos.y());
+            d->setInstantaneousVX(pos.x(), m_system);
+            d->setInstantaneousVY(pos.y(), m_system);
             changed = true;
         }
     }
@@ -217,8 +221,8 @@ bool QQuickCustomAffector::affectParticle(QQuickParticleData *d, qreal dt)
             pos += curPos;
         }
         if (pos != curPos) {
-            d->setInstantaneousX(pos.x());
-            d->setInstantaneousY(pos.y());
+            d->setInstantaneousX(pos.x(), m_system);
+            d->setInstantaneousY(pos.y(), m_system);
             changed = true;
         }
     }
diff --git a/src/particles/qquickcustomparticle.cpp b/src/particles/qquickcustomparticle.cpp
index 97cfdc7bf9..32b2fd847e 100644
--- a/src/particles/qquickcustomparticle.cpp
+++ b/src/particles/qquickcustomparticle.cpp
@@ -324,19 +324,18 @@ QQuickShaderEffectNode* QQuickCustomParticle::buildCustomNodes()
         return 0;
     }
 
-    if (m_groups.isEmpty())
+    if (groups().isEmpty())
         return 0;
 
     QQuickShaderEffectNode *rootNode = 0;
     QQuickShaderEffectMaterial *material = new QQuickShaderEffectMaterial;
     m_dirtyProgram = true;
 
-    foreach (const QString &str, m_groups){
-        int gIdx = m_system->groupIds[str];
-        int count = m_system->groupData[gIdx]->size();
+    for (auto groupId : groupIds()) {
+        int count = m_system->groupData[groupId]->size();
 
         QQuickShaderEffectNode* node = new QQuickShaderEffectNode();
-        m_nodes.insert(gIdx, node);
+        m_nodes.insert(groupId, node);
 
         node->setMaterial(material);
 
@@ -349,7 +348,7 @@ QQuickShaderEffectNode* QQuickCustomParticle::buildCustomNodes()
         node->setFlag(QSGNode::OwnsGeometry, true);
         PlainVertex *vertices = (PlainVertex *) g->vertexData();
         for (int p=0; p < count; ++p) {
-            commit(gIdx, p);
+            commit(groupId, p);
             vertices[0].tx = 0;
             vertices[0].ty = 0;
 
diff --git a/src/particles/qquickfriction.cpp b/src/particles/qquickfriction.cpp
index f234bc27ad..401f4cd8c9 100644
--- a/src/particles/qquickfriction.cpp
+++ b/src/particles/qquickfriction.cpp
@@ -80,8 +80,8 @@ bool QQuickFrictionAffector::affectParticle(QQuickParticleData *d, qreal dt)
 {
     if (!m_factor)
         return false;
-    qreal curVX = d->curVX();
-    qreal curVY = d->curVY();
+    qreal curVX = d->curVX(m_system);
+    qreal curVY = d->curVY(m_system);
     if (!curVX && !curVY)
         return false;
     qreal newVX = curVX + (curVX * m_factor * -1 * dt);
@@ -106,8 +106,8 @@ bool QQuickFrictionAffector::affectParticle(QQuickParticleData *d, qreal dt)
         }
     }
 
-    d->setInstantaneousVX(newVX);
-    d->setInstantaneousVY(newVY);
+    d->setInstantaneousVX(newVX, m_system);
+    d->setInstantaneousVY(newVY, m_system);
     return true;
 }
 QT_END_NAMESPACE
diff --git a/src/particles/qquickgravity.cpp b/src/particles/qquickgravity.cpp
index 54a03ac4bd..90f305f336 100644
--- a/src/particles/qquickgravity.cpp
+++ b/src/particles/qquickgravity.cpp
@@ -90,8 +90,8 @@ bool QQuickGravityAffector::affectParticle(QQuickParticleData *d, qreal dt)
         m_dy = m_magnitude * std::sin(m_angle * CONV);
     }
 
-    d->setInstantaneousVX(d->curVX() + m_dx*dt);
-    d->setInstantaneousVY(d->curVY() + m_dy*dt);
+    d->setInstantaneousVX(d->curVX(m_system) + m_dx*dt, m_system);
+    d->setInstantaneousVY(d->curVY(m_system) + m_dy*dt, m_system);
     return true;
 }
 QT_END_NAMESPACE
diff --git a/src/particles/qquickimageparticle.cpp b/src/particles/qquickimageparticle.cpp
index c88a0b002b..07cbee1383 100644
--- a/src/particles/qquickimageparticle.cpp
+++ b/src/particles/qquickimageparticle.cpp
@@ -1020,10 +1020,13 @@ void QQuickImageParticle::setEntryEffect(EntryEffect arg)
 void QQuickImageParticle::resetColor()
 {
     m_explicitColor = false;
-    foreach (const QString &str, m_groups)
-        foreach (QQuickParticleData* d, m_system->groupData[m_system->groupIds[str]]->data)
-            if (d->colorOwner == this)
+    for (auto groupId : groupIds()) {
+        for (QQuickParticleData* d : qAsConst(m_system->groupData[groupId]->data)) {
+            if (d->colorOwner == this) {
                 d->colorOwner = 0;
+            }
+        }
+    }
     m_color = QColor();
     m_color_variation = 0.0f;
     m_redVariation = 0.0f;
@@ -1036,10 +1039,13 @@ void QQuickImageParticle::resetColor()
 void QQuickImageParticle::resetRotation()
 {
     m_explicitRotation = false;
-    foreach (const QString &str, m_groups)
-        foreach (QQuickParticleData* d, m_system->groupData[m_system->groupIds[str]]->data)
-            if (d->rotationOwner == this)
+    for (auto groupId : groupIds()) {
+        for (QQuickParticleData* d : qAsConst(m_system->groupData[groupId]->data)) {
+            if (d->rotationOwner == this) {
                 d->rotationOwner = 0;
+            }
+        }
+    }
     m_rotation = 0;
     m_rotationVariation = 0;
     m_rotationVelocity = 0;
@@ -1050,10 +1056,13 @@ void QQuickImageParticle::resetRotation()
 void QQuickImageParticle::resetDeformation()
 {
     m_explicitDeformation = false;
-    foreach (const QString &str, m_groups)
-        foreach (QQuickParticleData* d, m_system->groupData[m_system->groupIds[str]]->data)
-            if (d->deformationOwner == this)
+    for (auto groupId : groupIds()) {
+        for (QQuickParticleData* d : qAsConst(m_system->groupData[groupId]->data)) {
+            if (d->deformationOwner == this) {
                 d->deformationOwner = 0;
+            }
+        }
+    }
     if (m_xVector)
         delete m_xVector;
     if (m_yVector)
@@ -1159,21 +1168,21 @@ QQuickParticleData* QQuickImageParticle::getShadowDatum(QQuickParticleData* datu
     //Will return datum if the datum is a sentinel or uninitialized, to centralize that one check
     if (datum->systemIndex == -1)
         return datum;
-    QQuickParticleGroupData* gd = m_system->groupData[datum->group];
-    if (!m_shadowData.contains(datum->group)) {
+    QQuickParticleGroupData* gd = m_system->groupData[datum->groupId];
+    if (!m_shadowData.contains(datum->groupId)) {
         QVector<QQuickParticleData*> data;
         const int gdSize = gd->size();
         data.reserve(gdSize);
         for (int i = 0; i < gdSize; i++) {
-            QQuickParticleData* datum = new QQuickParticleData(m_system);
+            QQuickParticleData* datum = new QQuickParticleData;
             *datum = *(gd->data[i]);
             data << datum;
         }
-        m_shadowData.insert(datum->group, data);
+        m_shadowData.insert(datum->groupId, data);
     }
     //### If dynamic resize is added, remember to potentially resize the shadow data on out-of-bounds access request
 
-    return m_shadowData[datum->group][datum->index];
+    return m_shadowData[datum->groupId][datum->index];
 }
 
 bool QQuickImageParticle::loadingSomething()
@@ -1255,9 +1264,9 @@ void QQuickImageParticle::finishBuildParticleNodes(QSGNode** node)
         perfLevel = Simple;
     }
 
-    foreach (const QString &str, m_groups){//For sharing higher levels, need to have highest used so it renders
-        int gIdx = m_system->groupIds[str];
-        foreach (QQuickParticlePainter* p, m_system->groupData[gIdx]->painters){
+    for (auto groupId : groupIds()) {
+        //For sharing higher levels, need to have highest used so it renders
+        for (QQuickParticlePainter* p : qAsConst(m_system->groupData[groupId]->painters)) {
             QQuickImageParticle* other = qobject_cast<QQuickImageParticle*>(p);
             if (other){
                 if (other->perfLevel > perfLevel) {
@@ -1382,16 +1391,15 @@ void QQuickImageParticle::finishBuildParticleNodes(QSGNode** node)
     }
 
     m_nodes.clear();
-    foreach (const QString &str, m_groups){
-        int gIdx = m_system->groupIds[str];
-        int count = m_system->groupData[gIdx]->size();
+    for (auto groupId : groupIds()) {
+        int count = m_system->groupData[groupId]->size();
         QSGGeometryNode* node = new QSGGeometryNode();
         node->setMaterial(m_material);
         node->markDirty(QSGNode::DirtyMaterial);
 
-        m_nodes.insert(gIdx, node);
-        m_idxStarts.insert(gIdx, m_lastIdxStart);
-        m_startsIdx.append(qMakePair<int,int>(m_lastIdxStart, gIdx));
+        m_nodes.insert(groupId, node);
+        m_idxStarts.insert(groupId, m_lastIdxStart);
+        m_startsIdx.append(qMakePair<int,int>(m_lastIdxStart, groupId));
         m_lastIdxStart += count;
 
         //Create Particle Geometry
@@ -1423,7 +1431,7 @@ void QQuickImageParticle::finishBuildParticleNodes(QSGNode** node)
             g->setDrawingMode(GL_TRIANGLES);
 
         for (int p=0; p < count; ++p)
-            commit(gIdx, p);//commit sets geometry for the node, has its own perfLevel switch
+            commit(groupId, p);//commit sets geometry for the node, has its own perfLevel switch
 
         if (perfLevel == Sprites)
             initTexCoords<SpriteVertex>((SpriteVertex*)g->vertexData(), vCount);
@@ -1538,10 +1546,9 @@ void QQuickImageParticle::prepareNextFrame(QSGNode **node)
 void QQuickImageParticle::spritesUpdate(qreal time)
 {
     // Sprite progression handled CPU side, so as to have per-frame control.
-    foreach (const QString &str, m_groups) {
-        int gIdx = m_system->groupIds[str];
-        foreach (QQuickParticleData* mainDatum, m_system->groupData[gIdx]->data) {
-            QSGGeometryNode *node = m_nodes[gIdx];
+    for (auto groupId : groupIds()) {
+        for (QQuickParticleData* mainDatum : qAsConst(m_system->groupData[groupId]->data)) {
+            QSGGeometryNode *node = m_nodes[groupId];
             if (!node)
                 continue;
             //TODO: Interpolate between two different animations if it's going to transition next frame
@@ -1549,7 +1556,7 @@ void QQuickImageParticle::spritesUpdate(qreal time)
             QQuickParticleData* datum = (mainDatum->animationOwner == this ? mainDatum : getShadowDatum(mainDatum));
             int spriteIdx = 0;
             for (int i = 0; i<m_startsIdx.count(); i++) {
-                if (m_startsIdx[i].second == gIdx){
+                if (m_startsIdx[i].second == groupId){
                     spriteIdx = m_startsIdx[i].first + datum->index;
                     break;
                 }
diff --git a/src/particles/qquickitemparticle.cpp b/src/particles/qquickitemparticle.cpp
index 86dc04ea5a..15cf19181e 100644
--- a/src/particles/qquickitemparticle.cpp
+++ b/src/particles/qquickitemparticle.cpp
@@ -206,8 +206,8 @@ void QQuickItemParticle::tick(int time)
                 m_managed << d->delegate;
         }
         if (d && d->delegate){//###Data can be zero if creating an item leads to a reset - this screws things up.
-            d->delegate->setX(d->curX() - d->delegate->width()/2);//TODO: adjust for system?
-            d->delegate->setY(d->curY() - d->delegate->height()/2);
+            d->delegate->setX(d->curX(m_system) - d->delegate->width() / 2); //TODO: adjust for system?
+            d->delegate->setY(d->curY(m_system) - d->delegate->height() / 2);
             QQuickItemParticleAttached* mpa = qobject_cast<QQuickItemParticleAttached*>(qmlAttachedPropertiesObject<QQuickItemParticle>(d->delegate));
             if (mpa){
                 mpa->m_mp = this;
@@ -231,10 +231,10 @@ void QQuickItemParticle::reset()
     // delete all managed items which had their logical particles cleared
     // but leave it alone if the logical particle is maintained
     QSet<QQuickItem*> lost = QSet<QQuickItem*>::fromList(m_managed);
-    foreach (const QString group, m_groups){
-        int gIdx = m_system->groupIds[group];
-        foreach (QQuickParticleData* d, m_system->groupData[gIdx]->data)
-                lost.remove(d->delegate);
+    for (auto groupId : groupIds()) {
+        for (QQuickParticleData* d : qAsConst(m_system->groupData[groupId]->data)) {
+            lost.remove(d->delegate);
+        }
     }
     m_deletables.append(lost.toList());
     //TODO: This doesn't yet handle calling detach on taken particles in the system reset case
@@ -249,11 +249,12 @@ QSGNode* QQuickItemParticle::updatePaintNode(QSGNode* n, UpdatePaintNodeData* d)
         m_pleaseReset = false;
         //Refill loadables, delayed here so as to only happen once per frame max
         //### Constant resetting might lead to m_loadables never being populated when tick() occurs
-        foreach (const QString group, m_groups){
-            int gIdx = m_system->groupIds[group];
-            foreach (QQuickParticleData* d, m_system->groupData[gIdx]->data)
-                if (!d->delegate && d->t != -1  && d->stillAlive())
+        for (auto groupId : groupIds()) {
+            for (QQuickParticleData* d : qAsConst(m_system->groupData[groupId]->data)) {
+                if (!d->delegate && d->t != -1  && d->stillAlive(m_system)) {
                     m_loadables << d;
+                }
+            }
         }
     }
     prepareNextFrame();
@@ -276,37 +277,32 @@ void QQuickItemParticle::prepareNextFrame()
         return;
 
     //TODO: Size, better fade?
-    foreach (const QString &str, m_groups){
-        const int gIdx = m_system->groupIds[str];
-        const QVector<QQuickParticleData*> dataVector = m_system->groupData.value(gIdx)->data;
-        const int count = dataVector.size();
-
-        for (int i=0; i<count; i++){
-            QQuickParticleData* data = dataVector.at(i);
+    for (auto groupId : groupIds()) {
+        for (QQuickParticleData* data : qAsConst(m_system->groupData[groupId]->data)) {
             QQuickItem* item = data->delegate;
             if (!item)
                 continue;
-            qreal t = ((timeStamp/1000.0) - data->t) / data->lifeSpan;
+            float t = ((timeStamp / 1000.0f) - data->t) / data->lifeSpan;
             if (m_stasis.contains(item)) {
                 data->t += dt;//Stasis effect
                 continue;
             }
-            if (t >= 1.0){//Usually happens from load
+            if (t >= 1.0f){//Usually happens from load
                 m_deletables << item;
                 data->delegate = 0;
             }else{//Fade
                 data->delegate->setVisible(true);
                 if (m_fade){
-                    qreal o = 1.;
-                    if (t<0.2)
-                        o = t*5;
-                    if (t>0.8)
+                    float o = 1.f;
+                    if (t <0.2f)
+                        o = t * 5;
+                    if (t > 0.8f)
                         o = (1-t)*5;
                     item->setOpacity(o);
                 }
             }
-            item->setX(data->curX() - item->width()/2 - m_systemOffset.x());
-            item->setY(data->curY() - item->height()/2 - m_systemOffset.y());
+            item->setX(data->curX(m_system) - item->width() / 2 - m_systemOffset.x());
+            item->setY(data->curY(m_system) - item->height() / 2 - m_systemOffset.y());
         }
     }
 }
diff --git a/src/particles/qquickparticleaffector.cpp b/src/particles/qquickparticleaffector.cpp
index 139b0d9bbe..6ed0d9e14a 100644
--- a/src/particles/qquickparticleaffector.cpp
+++ b/src/particles/qquickparticleaffector.cpp
@@ -162,13 +162,13 @@ bool QQuickParticleAffector::shouldAffect(QQuickParticleData* d)
 {
     if (!d)
         return false;
-    if (activeGroup(d->group)){
-        if ((m_onceOff && m_onceOffed.contains(qMakePair(d->group, d->index)))
-                || !d->stillAlive())
+    if (activeGroup(d->groupId)){
+        if ((m_onceOff && m_onceOffed.contains(qMakePair(d->groupId, d->index)))
+                || !d->stillAlive(m_system))
             return false;
         //Need to have previous location for affected anyways
         if (width() == 0 || height() == 0
-                || m_shape->contains(QRectF(m_offset.x(), m_offset.y(), width(), height()), QPointF(d->curX(), d->curY()))){
+                || m_shape->contains(QRectF(m_offset.x(), m_offset.y(), width(), height()), QPointF(d->curX(m_system), d->curY(m_system)))){
             if (m_whenCollidingWith.isEmpty() || isColliding(d)){
                 return true;
             }
@@ -182,9 +182,9 @@ void QQuickParticleAffector::postAffect(QQuickParticleData* d)
 {
     m_system->needsReset << d;
     if (m_onceOff)
-        m_onceOffed << qMakePair(d->group, d->index);
+        m_onceOffed << qMakePair(d->groupId, d->index);
     if (isAffectedConnected())
-        emit affected(d->curX(), d->curY());
+        emit affected(d->curX(m_system), d->curY(m_system));
 }
 
 const qreal QQuickParticleAffector::simulationDelta = 0.020;
@@ -200,7 +200,7 @@ void QQuickParticleAffector::affectSystem(qreal dt)
     if (m_onceOff)
         dt = 1.0;
     foreach (QQuickParticleGroupData* gd, m_system->groupData) {
-        if (activeGroup(m_system->groupData.key(gd))) {
+        if (activeGroup(gd->index)) {
             foreach (QQuickParticleData* d, gd->data) {
                 if (shouldAffect(d)) {
                     bool affected = false;
@@ -210,7 +210,7 @@ void QQuickParticleAffector::affectSystem(qreal dt)
                         m_system->timeInt -= myDt * 1000.0;
                         while (myDt > simulationDelta) {
                             m_system->timeInt += simulationDelta * 1000.0;
-                            if (d->alive())//Only affect during the parts it was alive for
+                            if (d->alive(m_system))//Only affect during the parts it was alive for
                                 affected = affectParticle(d, simulationDelta) || affected;
                             myDt -= simulationDelta;
                         }
@@ -234,8 +234,8 @@ bool QQuickParticleAffector::affectParticle(QQuickParticleData *, qreal )
 void QQuickParticleAffector::reset(QQuickParticleData* pd)
 {//TODO: This, among other ones, should be restructured so they don't all need to remember to call the superclass
     if (m_onceOff)
-        if (activeGroup(pd->group))
-            m_onceOffed.remove(qMakePair(pd->group, pd->index));
+        if (activeGroup(pd->groupId))
+            m_onceOffed.remove(qMakePair(pd->groupId, pd->index));
 }
 
 void QQuickParticleAffector::updateOffsets()
@@ -246,16 +246,16 @@ void QQuickParticleAffector::updateOffsets()
 
 bool QQuickParticleAffector::isColliding(QQuickParticleData *d)
 {
-    qreal myCurX = d->curX();
-    qreal myCurY = d->curY();
-    qreal myCurSize = d->curSize()/2;
+    qreal myCurX = d->curX(m_system);
+    qreal myCurY = d->curY(m_system);
+    qreal myCurSize = d->curSize(m_system) / 2;
     foreach (const QString &group, m_whenCollidingWith){
         foreach (QQuickParticleData* other, m_system->groupData[m_system->groupIds[group]]->data){
-            if (!other->stillAlive())
+            if (!other->stillAlive(m_system))
                 continue;
-            qreal otherCurX = other->curX();
-            qreal otherCurY = other->curY();
-            qreal otherCurSize = other->curSize()/2;
+            qreal otherCurX = other->curX(m_system);
+            qreal otherCurY = other->curY(m_system);
+            qreal otherCurSize = other->curSize(m_system) / 2;
             if ((myCurX + myCurSize > otherCurX - otherCurSize
                  && myCurX - myCurSize < otherCurX + otherCurSize)
                  && (myCurY + myCurSize > otherCurY - otherCurSize
diff --git a/src/particles/qquickparticleemitter.cpp b/src/particles/qquickparticleemitter.cpp
index 4d9f834492..6e116d450c 100644
--- a/src/particles/qquickparticleemitter.cpp
+++ b/src/particles/qquickparticleemitter.cpp
@@ -237,6 +237,8 @@ QQuickParticleEmitter::QQuickParticleEmitter(QQuickItem *parent) :
   , m_reset_last(true)
   , m_last_timestamp(-1)
   , m_last_emission(0)
+  , m_groupIdNeedRecalculation(false)
+  , m_groupId(QQuickParticleGroupData::DefaultGroupID)
 
 {
     //TODO: Reset velocity/acc back to null vector? Or allow null pointer?
@@ -257,10 +259,22 @@ bool QQuickParticleEmitter::isEmitConnected()
     IS_SIGNAL_CONNECTED(this, QQuickParticleEmitter, emitParticles, (QQmlV4Handle));
 }
 
+void QQuickParticleEmitter::reclaculateGroupId() const
+{
+    if (!m_system) {
+        m_groupId = QQuickParticleGroupData::InvalidID;
+        return;
+    }
+    m_groupId = m_system->groupIds.value(group(), QQuickParticleGroupData::InvalidID);
+    m_groupIdNeedRecalculation = m_groupId == QQuickParticleGroupData::InvalidID;
+}
+
 void QQuickParticleEmitter::componentComplete()
 {
     if (!m_system && qobject_cast<QQuickParticleSystem*>(parentItem()))
         setSystem(qobject_cast<QQuickParticleSystem*>(parentItem()));
+    if (m_system)
+        m_system->finishRegisteringParticleEmitter(this);
     QQuickItem::componentComplete();
 }
 
@@ -319,13 +333,6 @@ void QQuickParticleEmitter::setMaxParticleCount(int arg)
     }
 }
 
-int QQuickParticleEmitter::particleCount() const
-{
-    if (m_maxParticleCount >= 0)
-        return m_maxParticleCount;
-    return m_particlesPerSecond*((m_particleDuration+m_particleDurationVariation)/1000.0);
-}
-
 void QQuickParticleEmitter::setVelocityFromMovement(qreal t)
 {
     if (t == m_velocity_from_movement)
@@ -402,7 +409,6 @@ void QQuickParticleEmitter::emitWindow(int timeStamp)
         //int pos = m_last_particle % m_particle_count;
         QQuickParticleData* datum = m_system->newDatum(m_system->groupIds[m_group], !m_overwrite);
         if (datum){//actually emit(otherwise we've been asked to skip this one)
-            datum->e = this;//###useful?
             qreal t = 1 - (pt - opt) / dt;
             qreal vx =
               - 2 * ax * (1 - t)
@@ -475,7 +481,7 @@ void QQuickParticleEmitter::emitWindow(int timeStamp)
     }
 
     foreach (QQuickParticleData* d, toEmit)
-            m_system->emitParticle(d);
+            m_system->emitParticle(d, this);
 
     if (isEmitConnected()) {
         QQmlEngine *qmlEngine = ::qmlEngine(this);
@@ -487,7 +493,7 @@ void QQuickParticleEmitter::emitWindow(int timeStamp)
         QV4::ScopedArrayObject array(scope, v4->newArrayObject(toEmit.size()));
         QV4::ScopedValue v(scope);
         for (int i=0; i<toEmit.size(); i++)
-            array->putIndexed(i, (v = toEmit[i]->v4Value()));
+            array->putIndexed(i, (v = toEmit[i]->v4Value(m_system)));
 
         emitParticles(QQmlV4Handle(array));//A chance for arbitrary JS changes
     }
diff --git a/src/particles/qquickparticleemitter_p.h b/src/particles/qquickparticleemitter_p.h
index e0036c4007..9b114ad46b 100644
--- a/src/particles/qquickparticleemitter_p.h
+++ b/src/particles/qquickparticleemitter_p.h
@@ -119,6 +119,13 @@ public:
         return m_group;
     }
 
+    QQuickParticleGroupData::ID groupId() const
+    {
+        if (m_groupIdNeedRecalculation)
+            reclaculateGroupId();
+        return m_groupId;
+    }
+
     int particleDurationVariation() const
     {
         return m_particleDurationVariation;
@@ -185,6 +192,7 @@ public Q_SLOTS:
     {
         if (m_system != arg) {
             m_system = arg;
+            m_groupIdNeedRecalculation = true;
             if (m_system)
                 m_system->registerParticleEmitter(this);
             Q_EMIT systemChanged(arg);
@@ -195,6 +203,7 @@ public Q_SLOTS:
     {
         if (m_group != arg) {
             m_group = arg;
+            m_groupIdNeedRecalculation = true;
             Q_EMIT groupChanged(arg);
         }
     }
@@ -266,7 +275,12 @@ public Q_SLOTS:
 
        virtual void reset();
 public:
-       int particleCount() const;
+       int particleCount() const
+       {
+           if (m_maxParticleCount >= 0)
+               return m_maxParticleCount;
+           return m_particlesPerSecond*((m_particleDuration+m_particleDurationVariation)/1000.0);
+       }
 
        QQuickParticleExtruder* extruder() const
        {
@@ -314,7 +328,6 @@ protected:
        int m_particleDurationVariation;
        bool m_enabled;
        QQuickParticleSystem* m_system;
-       QString m_group;
        QQuickParticleExtruder* m_extruder;
        QQuickParticleExtruder* m_defaultExtruder;
        QQuickParticleExtruder* effectiveExtruder();
@@ -345,7 +358,14 @@ protected:
        QPointF m_last_last_last_emitter;
 
        bool isEmitConnected();
-private:
+
+private: // methods
+       void reclaculateGroupId() const;
+
+private: // data
+       QString m_group;
+       mutable bool m_groupIdNeedRecalculation;
+       mutable QQuickParticleGroupData::ID m_groupId;
        QQuickDirection m_nullVector;
 
 };
diff --git a/src/particles/qquickparticlepainter.cpp b/src/particles/qquickparticlepainter.cpp
index 134689713d..d6303eb219 100644
--- a/src/particles/qquickparticlepainter.cpp
+++ b/src/particles/qquickparticlepainter.cpp
@@ -64,9 +64,13 @@ QT_BEGIN_NAMESPACE
 
     If empty, it will paint the default particle group ("").
 */
-QQuickParticlePainter::QQuickParticlePainter(QQuickItem *parent) :
-    QQuickItem(parent),
-    m_system(0), m_count(0), m_pleaseReset(true), m_window(0)
+QQuickParticlePainter::QQuickParticlePainter(QQuickItem *parent)
+    : QQuickItem(parent)
+    , m_system(0)
+    , m_count(0)
+    , m_pleaseReset(true)
+    , m_window(0)
+    , m_groupIdsNeedRecalculation(false)
 {
 }
 
@@ -89,11 +93,32 @@ void QQuickParticlePainter::componentComplete()
     QQuickItem::componentComplete();
 }
 
+void QQuickParticlePainter::recalculateGroupIds() const
+{
+    if (!m_system) {
+        m_groupIds.clear();
+        return;
+    }
+
+    m_groupIdsNeedRecalculation = false;
+    m_groupIds.clear();
+
+    for (const QString &str : groups()) {
+        QQuickParticleGroupData::ID groupId = m_system->groupIds.value(str, QQuickParticleGroupData::InvalidID);
+        if (groupId == QQuickParticleGroupData::InvalidID) {
+            // invalid data, not finished setting up, or whatever. Fallback: do not cache.
+            m_groupIdsNeedRecalculation = true;
+        } else {
+            m_groupIds.append(groupId);
+        }
+    }
+}
 
 void QQuickParticlePainter::setSystem(QQuickParticleSystem *arg)
 {
     if (m_system != arg) {
         m_system = arg;
+        m_groupIdsNeedRecalculation = true;
         if (m_system){
             m_system->registerParticlePainter(this);
             reset();
@@ -102,19 +127,29 @@ void QQuickParticlePainter::setSystem(QQuickParticleSystem *arg)
     }
 }
 
+void QQuickParticlePainter::setGroups(const QStringList &arg)
+{
+    if (m_groups != arg) {
+        m_groups = arg;
+        m_groupIdsNeedRecalculation = true;
+        //Note: The system watches this as it has to recalc things when groups change. It will request a reset if necessary
+        Q_EMIT groupsChanged(arg);
+    }
+}
+
 void QQuickParticlePainter::load(QQuickParticleData* d)
 {
-    initialize(d->group, d->index);
+    initialize(d->groupId, d->index);
     if (m_pleaseReset)
         return;
-    m_pendingCommits << qMakePair<int, int>(d->group, d->index);
+    m_pendingCommits << qMakePair<int, int>(d->groupId, d->index);
 }
 
 void QQuickParticlePainter::reload(QQuickParticleData* d)
 {
     if (m_pleaseReset)
         return;
-    m_pendingCommits << qMakePair<int, int>(d->group, d->index);
+    m_pendingCommits << qMakePair<int, int>(d->groupId, d->index);
 }
 
 void QQuickParticlePainter::reset()
@@ -133,11 +168,6 @@ void QQuickParticlePainter::setCount(int c)//### TODO: some resizeing so that pa
     reset();
 }
 
-int QQuickParticlePainter::count()
-{
-    return m_count;
-}
-
 void QQuickParticlePainter::calcSystemOffset(bool resetPending)
 {
     if (!m_system || !parentItem())
diff --git a/src/particles/qquickparticlepainter_p.h b/src/particles/qquickparticlepainter_p.h
index 719dfdb3d8..064ce27fe8 100644
--- a/src/particles/qquickparticlepainter_p.h
+++ b/src/particles/qquickparticlepainter_p.h
@@ -64,25 +64,40 @@ class QQuickParticlePainter : public QQuickItem
     Q_PROPERTY(QQuickParticleSystem* system READ system WRITE setSystem NOTIFY systemChanged)
     Q_PROPERTY(QStringList groups READ groups WRITE setGroups NOTIFY groupsChanged)
 
+public: // data
+    typedef QQuickParticleVarLengthArray<QQuickParticleGroupData::ID, 4> GroupIDs;
+
 public:
     explicit QQuickParticlePainter(QQuickItem *parent = 0);
     //Data Interface to system
     void load(QQuickParticleData*);
     void reload(QQuickParticleData*);
     void setCount(int c);
-    int count();
+
+    int count() const
+    {
+        return m_count;
+    }
+
     void performPendingCommits();//Called from updatePaintNode
     QQuickParticleSystem* system() const
     {
         return m_system;
     }
 
-
     QStringList groups() const
     {
         return m_groups;
     }
 
+    const GroupIDs &groupIds() const
+    {
+        if (m_groupIdsNeedRecalculation) {
+            recalculateGroupIds();
+        }
+        return m_groupIds;
+    }
+
     void itemChange(ItemChange, const ItemChangeData &);
 
 Q_SIGNALS:
@@ -94,14 +109,7 @@ Q_SIGNALS:
 public Q_SLOTS:
     void setSystem(QQuickParticleSystem* arg);
 
-    void setGroups(const QStringList &arg)
-    {
-        if (m_groups != arg) {
-            m_groups = arg;
-            //Note: The system watches this as it has to recalc things when groups change. It will request a reset if necessary
-            Q_EMIT groupsChanged(arg);
-        }
-    }
+    void setGroups(const QStringList &arg);
 
     void calcSystemOffset(bool resetPending = false);
 
@@ -130,13 +138,18 @@ protected:
     friend class QQuickParticleSystem;
     int m_count;
     bool m_pleaseReset;//Used by subclasses, but it's a nice optimization to know when stuff isn't going to matter.
-    QStringList m_groups;
     QPointF m_systemOffset;
 
     QQuickWindow *m_window;
 
-private:
+private: // methods
+    void recalculateGroupIds() const;
+
+private: // data
+    QStringList m_groups;
     QSet<QPair<int,int> > m_pendingCommits;
+    mutable GroupIDs m_groupIds;
+    mutable bool m_groupIdsNeedRecalculation;
 };
 
 QT_END_NAMESPACE
diff --git a/src/particles/qquickparticlesystem.cpp b/src/particles/qquickparticlesystem.cpp
index 603515dc66..17d9e49d63 100644
--- a/src/particles/qquickparticlesystem.cpp
+++ b/src/particles/qquickparticlesystem.cpp
@@ -199,24 +199,8 @@ DEFINE_BOOL_CONFIG_OPTION(qmlParticlesDebug, QML_PARTICLES_DEBUG)
     Discards all currently existing particles.
 
 */
-const qreal EPSILON = 0.001;
-//Utility functions for when within 1ms is close enough
-bool timeEqualOrGreater(qreal a, qreal b)
-{
-    return (a+EPSILON >= b);
-}
-
-bool timeLess(qreal a, qreal b)
-{
-    return (a-EPSILON < b);
-}
 
-bool timeEqual(qreal a, qreal b)
-{
-    return (a+EPSILON > b) && (a-EPSILON < b);
-}
-
-int roundedTime(qreal a)
+static inline int roundedTime(qreal a)
 {// in ms
     return (int)qRound(a*1000.0);
 }
@@ -330,7 +314,10 @@ void QQuickParticleDataHeap::bubbleDown(int idx)//tends to be called log n times
     }
 }
 
-QQuickParticleGroupData::QQuickParticleGroupData(int id, QQuickParticleSystem* sys):index(id),m_size(0),m_system(sys)
+QQuickParticleGroupData::QQuickParticleGroupData(const QString &name, QQuickParticleSystem* sys)
+    : index(sys->registerParticleGroupData(name, this))
+    , m_size(0)
+    , m_system(sys)
 {
     initList();
 }
@@ -341,11 +328,6 @@ QQuickParticleGroupData::~QQuickParticleGroupData()
         delete d;
 }
 
-int QQuickParticleGroupData::size()
-{
-    return m_size;
-}
-
 QString QQuickParticleGroupData::name()//### Worth caching as well?
 {
     return m_system->groupIds.key(index);
@@ -357,11 +339,11 @@ void QQuickParticleGroupData::setSize(int newSize)
         return;
     Q_ASSERT(newSize > m_size);//XXX allow shrinking
     data.resize(newSize);
+    freeList.resize(newSize);
     for (int i=m_size; i<newSize; i++) {
-        data[i] = new QQuickParticleData(m_system);
-        data[i]->group = index;
+        data[i] = new QQuickParticleData;
+        data[i]->groupId = index;
         data[i]->index = i;
-        reusableIndexes << i;
     }
     int delta = newSize - m_size;
     m_size = newSize;
@@ -376,21 +358,20 @@ void QQuickParticleGroupData::initList()
 
 void QQuickParticleGroupData::kill(QQuickParticleData* d)
 {
-    Q_ASSERT(d->group == index);
+    Q_ASSERT(d->groupId == index);
     d->lifeSpan = 0;//Kill off
     foreach (QQuickParticlePainter* p, painters)
         p->reload(d);
-    reusableIndexes << d->index;
+    freeList.free(d->index);
 }
 
 QQuickParticleData* QQuickParticleGroupData::newDatum(bool respectsLimits)
 {
     //recycle();//Extra recycler round to be sure?
 
-    while (!reusableIndexes.empty()) {
-        int idx = *(reusableIndexes.begin());
-        reusableIndexes.remove(idx);
-        if (data[idx]->stillAlive()) {// ### This means resurrection of 'dead' particles. Is that allowed?
+    while (freeList.hasUnusedEntries()) {
+        int idx = freeList.alloc();
+        if (data[idx]->stillAlive(m_system)) {// ### This means resurrection of 'dead' particles. Is that allowed?
             prepareRecycler(data[idx]);
             continue;
         }
@@ -401,16 +382,17 @@ QQuickParticleData* QQuickParticleGroupData::newDatum(bool respectsLimits)
 
     int oldSize = m_size;
     setSize(oldSize + 10);//###+1,10%,+10? Choose something non-arbitrarily
-    reusableIndexes.remove(oldSize);
-    return data[oldSize];
+    int idx = freeList.alloc();
+    Q_ASSERT(idx == oldSize);
+    return data[idx];
 }
 
 bool QQuickParticleGroupData::recycle()
 {
     while (dataHeap.top() <= m_system->timeInt) {
         foreach (QQuickParticleData* datum, dataHeap.pop()) {
-            if (!datum->stillAlive()) {
-                reusableIndexes << datum->index;
+            if (!datum->stillAlive(m_system)) {
+                freeList.free(datum->index);
             } else {
                 prepareRecycler(datum); //ttl has been altered mid-way, put it back
             }
@@ -418,7 +400,7 @@ bool QQuickParticleGroupData::recycle()
     }
 
     //TODO: If the data is clear, gc (consider shrinking stack size)?
-    return reusableIndexes.count() == m_size;
+    return freeList.count() == 0;
 }
 
 void QQuickParticleGroupData::prepareRecycler(QQuickParticleData* d)
@@ -427,17 +409,15 @@ void QQuickParticleGroupData::prepareRecycler(QQuickParticleData* d)
         dataHeap.insert(d);
     } else {
         while ((roundedTime(d->t) + 2*m_system->maxLife/3) <= m_system->timeInt)
-            d->extendLife(m_system->maxLife/3000.0);
+            d->extendLife(m_system->maxLife / 3000.0, m_system);
         dataHeap.insertTimed(d, roundedTime(d->t) + 2*m_system->maxLife/3);
     }
 }
 
-QQuickParticleData::QQuickParticleData(QQuickParticleSystem* sys)
-    : e(0)
-    , system(sys)
-    , index(0)
+QQuickParticleData::QQuickParticleData()
+    : index(0)
     , systemIndex(-1)
-    , group(0)
+    , groupId(0)
     , colorOwner(0)
     , rotationOwner(0)
     , deformationOwner(0)
@@ -493,9 +473,7 @@ QQuickParticleData &QQuickParticleData::operator=(const QQuickParticleData &othe
 {
     clone(other);
 
-    group = other.group;
-    e = other.e;
-    system = other.system;
+    groupId = other.groupId;
     index = other.index;
     systemIndex = other.systemIndex;
     // Lazily initialized
@@ -545,150 +523,34 @@ void QQuickParticleData::clone(const QQuickParticleData& other)
     animationOwner = other.animationOwner;
 }
 
-QQmlV4Handle QQuickParticleData::v4Value()
+QQmlV4Handle QQuickParticleData::v4Value(QQuickParticleSystem* particleSystem)
 {
     if (!v8Datum)
-        v8Datum = new QQuickV4ParticleData(QQmlEnginePrivate::getV8Engine(qmlEngine(system)), this);
+        v8Datum = new QQuickV4ParticleData(QQmlEnginePrivate::getV8Engine(qmlEngine(particleSystem)), this, particleSystem);
     return v8Datum->v4Value();
 }
-//sets the x accleration without affecting the instantaneous x velocity or position
-void QQuickParticleData::setInstantaneousAX(qreal ax)
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    qreal vx = (this->vx + t*this->ax) - t*ax;
-    qreal ex = this->x + this->vx * t + 0.5 * this->ax * t * t;
-    qreal x = ex - t*vx - 0.5 * t*t*ax;
-
-    this->ax = ax;
-    this->vx = vx;
-    this->x = x;
-}
 
-//sets the x velocity without affecting the instantaneous x postion
-void QQuickParticleData::setInstantaneousVX(qreal vx)
+void QQuickParticleData::debugDump(QQuickParticleSystem* particleSystem) const
 {
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    qreal evx = vx - t*this->ax;
-    qreal ex = this->x + this->vx * t + 0.5 * this->ax * t * t;
-    qreal x = ex - t*evx - 0.5 * t*t*this->ax;
-
-    this->vx = evx;
-    this->x = x;
-}
-
-//sets the instantaneous x postion
-void QQuickParticleData::setInstantaneousX(qreal x)
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    this->x = x - t*this->vx - 0.5 * t*t*this->ax;
-}
-
-//sets the y accleration without affecting the instantaneous y velocity or position
-void QQuickParticleData::setInstantaneousAY(qreal ay)
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    qreal vy = (this->vy + t*this->ay) - t*ay;
-    qreal ey = this->y + this->vy * t + 0.5 * this->ay * t * t;
-    qreal y = ey - t*vy - 0.5 * t*t*ay;
-
-    this->ay = ay;
-    this->vy = vy;
-    this->y = y;
-}
-
-//sets the y velocity without affecting the instantaneous y position
-void QQuickParticleData::setInstantaneousVY(qreal vy)
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    qreal evy = vy - t*this->ay;
-    qreal ey = this->y + this->vy * t + 0.5 * this->ay * t * t;
-    qreal y = ey - t*evy - 0.5 * t*t*this->ay;
-
-    this->vy = evy;
-    this->y = y;
-}
-
-//sets the instantaneous Y position
-void QQuickParticleData::setInstantaneousY(qreal y)
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    this->y = y - t*this->vy - 0.5 * t*t*this->ay;
-}
-
-qreal QQuickParticleData::curX() const
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    return this->x + this->vx * t + 0.5 * this->ax * t * t;
-}
-
-qreal QQuickParticleData::curVX() const
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    return this->vx + t*this->ax;
-}
-
-qreal QQuickParticleData::curY() const
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    return y + vy * t + 0.5 * ay * t * t;
-}
-
-qreal QQuickParticleData::curVY() const
-{
-    qreal t = (system->timeInt / 1000.0) - this->t;
-    return vy + t*ay;
-}
-
-void QQuickParticleData::debugDump()
-{
-    qDebug() << "Particle" << systemIndex << group << "/" << index << stillAlive()
+    qDebug() << "Particle" << systemIndex << groupId << "/" << index << stillAlive(particleSystem)
              << "Pos: " << x << "," << y
              << "Vel: " << vx << "," << vy
              << "Acc: " << ax << "," << ay
              << "Size: " << size << "," << endSize
-             << "Time: " << t << "," <<lifeSpan << ";" << (system->timeInt / 1000.0) ;
-}
-
-bool QQuickParticleData::stillAlive()
-{
-    if (!system)
-        return false;
-    return (t + lifeSpan - EPSILON) > ((qreal)system->timeInt/1000.0);
-}
-
-bool QQuickParticleData::alive()
-{
-    if (!system)
-        return false;
-    qreal st = ((qreal)system->timeInt/1000.0);
-    return (t + EPSILON) < st && (t + lifeSpan - EPSILON) > st;
+             << "Time: " << t << "," <<lifeSpan << ";" << (particleSystem->timeInt / 1000.0) ;
 }
 
-float QQuickParticleData::curSize()
+void QQuickParticleData::extendLife(float time, QQuickParticleSystem* particleSystem)
 {
-    if (!system || !lifeSpan)
-        return 0.0f;
-    return size + (endSize - size) * (1 - (lifeLeft() / lifeSpan));
-}
-
-float QQuickParticleData::lifeLeft()
-{
-    if (!system)
-        return 0.0f;
-    return (t + lifeSpan) - (system->timeInt/1000.0);
-}
-
-void QQuickParticleData::extendLife(float time)
-{
-    qreal newX = curX();
-    qreal newY = curY();
-    qreal newVX = curVX();
-    qreal newVY = curVY();
+    qreal newX = curX(particleSystem);
+    qreal newY = curY(particleSystem);
+    qreal newVX = curVX(particleSystem);
+    qreal newVY = curVY(particleSystem);
 
     t += time;
     animT += time;
 
-    qreal elapsed = (system->timeInt / 1000.0) - t;
+    qreal elapsed = (particleSystem->timeInt / 1000.0) - t;
     qreal evy = newVY - elapsed*ay;
     qreal ey = newY - elapsed*evy - 0.5 * elapsed*elapsed*ay;
     qreal evx = newVX - elapsed*ax;
@@ -703,6 +565,7 @@ void QQuickParticleData::extendLife(float time)
 QQuickParticleSystem::QQuickParticleSystem(QQuickItem *parent) :
     QQuickItem(parent),
     stateEngine(0),
+    nextFreeGroupId(0),
     m_animation(0),
     m_running(true),
     initialized(0),
@@ -732,11 +595,11 @@ void QQuickParticleSystem::initGroups()
     qDeleteAll(groupData);
     groupData.clear();
     groupIds.clear();
+    nextFreeGroupId = 0;
 
-    QQuickParticleGroupData* gd = new QQuickParticleGroupData(0, this);//Default group
-    groupData.insert(0,gd);
-    groupIds.insert(QString(), 0);
-    m_nextGroupId = 1;
+    QQuickParticleGroupData *pd = new QQuickParticleGroupData(QString(), this); // Default group
+    Q_ASSERT(pd->index == 0);
+    Q_UNUSED(pd);
 }
 
 void QQuickParticleSystem::registerParticlePainter(QQuickParticlePainter* p)
@@ -755,11 +618,16 @@ void QQuickParticleSystem::registerParticleEmitter(QQuickParticleEmitter* e)
     if (m_debugMode)
         qDebug() << "Registering Emitter" << e << "to" << this;
     m_emitters << QPointer<QQuickParticleEmitter>(e);//###How to get them out?
+}
+
+void QQuickParticleSystem::finishRegisteringParticleEmitter(QQuickParticleEmitter* e)
+{
     connect(e, SIGNAL(particleCountChanged()),
             this, SLOT(emittersChanged()));
     connect(e, SIGNAL(groupChanged(QString)),
             this, SLOT(emittersChanged()));
-    emittersChanged();
+    if (m_componentComplete)
+        emittersChanged();
     e->reset();//Start, so that starttime factors appropriately
 }
 
@@ -848,6 +716,34 @@ void QQuickParticleSystem::stateRedirect(QQuickParticleGroup* group, QQuickParti
     qWarning() << value << " was placed inside a particle system state but cannot be taken into the particle system. It will be lost.";
 }
 
+
+int QQuickParticleSystem::registerParticleGroupData(const QString &name, QQuickParticleGroupData *pgd)
+{
+    Q_ASSERT(!groupIds.contains(name));
+    int id;
+    if (nextFreeGroupId >= groupData.size()) {
+        groupData.push_back(pgd);
+        nextFreeGroupId = groupData.size();
+        id = nextFreeGroupId - 1;
+    } else {
+        id = nextFreeGroupId;
+        groupData[id] = pgd;
+        searchNextFreeGroupId();
+    }
+    groupIds.insert(name, id);
+    return id;
+}
+
+void QQuickParticleSystem::searchNextFreeGroupId()
+{
+    ++nextFreeGroupId;
+    for (int ei = groupData.size(); nextFreeGroupId != ei; ++nextFreeGroupId) {
+        if (groupData[nextFreeGroupId] == nullptr) {
+            return;
+        }
+    }
+}
+
 void QQuickParticleSystem::componentComplete()
 
 {
@@ -906,25 +802,21 @@ void QQuickParticleSystem::loadPainter(QObject *p)
 
     QQuickParticlePainter* painter = qobject_cast<QQuickParticlePainter*>(p);
     Q_ASSERT(painter);//XXX
-    foreach (QQuickParticleGroupData* sg, groupData)
-        sg->painters.remove(painter);
+    for (QQuickParticleGroupData* sg : groupData) {
+        sg->painters.removeOne(painter);
+    }
+
     int particleCount = 0;
     if (painter->groups().isEmpty()) {//Uses default particle
-        QStringList def;
-        def << QString();
+        static QStringList def = QStringList() << QString();
         painter->setGroups(def);
         particleCount += groupData[0]->size();
         groupData[0]->painters << painter;
     } else {
-        foreach (const QString &group, painter->groups()) {
-            if (group != QLatin1String("") && !groupIds[group]) {//new group
-                int id = m_nextGroupId++;
-                QQuickParticleGroupData* gd = new QQuickParticleGroupData(id, this);
-                groupIds.insert(group, id);
-                groupData.insert(id, gd);
-            }
-            particleCount += groupData[groupIds[group]]->size();
-            groupData[groupIds[group]]->painters << painter;
+        for (auto groupId : painter->groupIds()) {
+            QQuickParticleGroupData *gd = groupData[groupId];
+            particleCount += gd->size();
+            gd->painters << painter;
         }
     }
     painter->setCount(particleCount);
@@ -939,44 +831,42 @@ void QQuickParticleSystem::emittersChanged()
 
     QVector<int> previousSizes;
     QVector<int> newSizes;
-    previousSizes.reserve(m_nextGroupId);
-    newSizes.reserve(m_nextGroupId);
-    for (int i=0; i<m_nextGroupId; i++) {
+    previousSizes.reserve(groupData.size());
+    newSizes.reserve(groupData.size());
+    for (int i = 0, ei = groupData.size(); i != ei; ++i) {
         previousSizes << groupData[i]->size();
         newSizes << 0;
     }
 
     // Populate groups and set sizes.
-    for (int i = 0; i < m_emitters.count(); ++i) {
+    for (int i = 0; i < m_emitters.count(); ) {
         QQuickParticleEmitter *e = m_emitters.at(i);
         if (!e) {
             m_emitters.removeAt(i);
-            i--;
             continue;
         }
 
-        if (!e->group().isEmpty() &&
-            !groupIds.contains(e->group())) {
-            int id = m_nextGroupId++;
-            QQuickParticleGroupData* gd = new QQuickParticleGroupData(id, this);
-            groupIds.insert(e->group(), id);
-            groupData.insert(id, gd);
+        int groupId = e->groupId();
+        if (groupId == QQuickParticleGroupData::InvalidID) {
+            groupId = (new QQuickParticleGroupData(e->group(), this))->index;
             previousSizes << 0;
             newSizes << 0;
         }
-        newSizes[groupIds[e->group()]] += e->particleCount();
+        newSizes[groupId] += e->particleCount();
         //###: Cull emptied groups?
+
+        ++i;
     }
 
     //TODO: Garbage collection?
     particleCount = 0;
-    for (int i=0; i<m_nextGroupId; i++) {
+    for (int i = 0, ei = groupData.size(); i != ei; ++i) {
         groupData[i]->setSize(qMax(newSizes[i], previousSizes[i]));
         particleCount += groupData[i]->size();
     }
 
     if (m_debugMode)
-        qDebug() << "Particle system emitters changed. New particle count: " << particleCount;
+        qDebug() << "Particle system emitters changed. New particle count: " << particleCount << "in" << groupData.size() << "groups.";
 
     if (particleCount > bySysIdx.size())//New datum requests haven't updated it
         bySysIdx.resize(particleCount);
@@ -1008,17 +898,15 @@ void QQuickParticleSystem::createEngine()
             }
         }
         if (!exists) {
-            int id = m_nextGroupId++;
-            QQuickParticleGroupData* gd = new QQuickParticleGroupData(id, this);
-            groupIds.insert(group->name(), id);
-            groupData.insert(id, gd);
+            new QQuickParticleGroupData(group->name(), this);
         }
     }
 
     if (m_groups.count()) {
         //Reorder groups List so as to have the same order as groupData
+        // TODO: can't we just merge the two lists?
         QList<QQuickParticleGroup*> newList;
-        for (int i=0; i<m_nextGroupId; i++) {
+        for (int i = 0, ei = groupData.size(); i != ei; ++i) {
             bool exists = false;
             QString name = groupData[i]->name();
             foreach (QQuickParticleGroup* existing, m_groups) {
@@ -1061,7 +949,7 @@ void QQuickParticleSystem::particleStateChange(int idx)
 
 void QQuickParticleSystem::moveGroups(QQuickParticleData *d, int newGIdx)
 {
-    if (!d || newGIdx == d->group)
+    if (!d || newGIdx == d->groupId)
         return;
 
     QQuickParticleData* pd = newDatum(newGIdx, false, d->systemIndex);
@@ -1072,7 +960,7 @@ void QQuickParticleSystem::moveGroups(QQuickParticleData *d, int newGIdx)
     finishNewDatum(pd);
 
     d->systemIndex = -1;
-    groupData[d->group]->kill(d);
+    groupData[d->groupId]->kill(d);
 }
 
 int QQuickParticleSystem::nextSystemIndex()
@@ -1114,17 +1002,17 @@ QQuickParticleData* QQuickParticleSystem::newDatum(int groupId, bool respectLimi
     bySysIdx[ret->systemIndex] = ret;
 
     if (stateEngine)
-        stateEngine->start(ret->systemIndex, ret->group);
+        stateEngine->start(ret->systemIndex, ret->groupId);
 
     m_empty = false;
     return ret;
 }
 
-void QQuickParticleSystem::emitParticle(QQuickParticleData* pd)
+void QQuickParticleSystem::emitParticle(QQuickParticleData* pd, QQuickParticleEmitter* particleEmitter)
 {// called from prepareNextFrame()->emitWindow - enforce?
     //Account for relative emitter position
     bool okay = false;
-    QTransform t = pd->e->itemTransform(this, &okay);
+    QTransform t = particleEmitter->itemTransform(this, &okay);
     if (okay) {
         qreal tx,ty;
         t.map(pd->x, pd->y, &tx, &ty);
@@ -1138,12 +1026,12 @@ void QQuickParticleSystem::emitParticle(QQuickParticleData* pd)
 void QQuickParticleSystem::finishNewDatum(QQuickParticleData *pd)
 {
     Q_ASSERT(pd);
-    groupData[pd->group]->prepareRecycler(pd);
+    groupData[pd->groupId]->prepareRecycler(pd);
 
     foreach (QQuickParticleAffector *a, m_affectors)
         if (a && a->m_needsReset)
             a->reset(pd);
-    foreach (QQuickParticlePainter* p, groupData[pd->group]->painters)
+    foreach (QQuickParticlePainter* p, groupData[pd->groupId]->painters)
         if (p)
             p->load(pd);
 }
@@ -1177,7 +1065,7 @@ void QQuickParticleSystem::updateCurrentTime( int currentTime )
     foreach (QQuickParticleAffector* a, m_affectors)
         a->affectSystem(dt);
     foreach (QQuickParticleData* d, needsReset)
-        foreach (QQuickParticlePainter* p, groupData[d->group]->painters)
+        foreach (QQuickParticlePainter* p, groupData[d->groupId]->painters)
             p->reload(d);
 
     if (oldClear != m_empty)
diff --git a/src/particles/qquickparticlesystem_p.h b/src/particles/qquickparticlesystem_p.h
index 5a1ab5022d..b57d55bd98 100644
--- a/src/particles/qquickparticlesystem_p.h
+++ b/src/particles/qquickparticlesystem_p.h
@@ -61,10 +61,35 @@
 #include <QAbstractAnimation>
 #include <QtQml/qqml.h>
 #include <private/qv8engine_p.h> //For QQmlV4Handle
+#include <private/qv4util_p.h>
 #include "qtquickparticlesglobal_p.h"
 
 QT_BEGIN_NAMESPACE
 
+template<class T, int Prealloc>
+class QQuickParticleVarLengthArray: public QVarLengthArray<T, Prealloc>
+{
+public:
+    void insert(const T &element)
+    {
+        if (!this->contains(element)) {
+            this->append(element);
+        }
+    }
+
+    bool removeOne(const T &element)
+    {
+        for (int i = 0; i < this->size(); ++i) {
+            if (this->at(i) == element) {
+                this->remove(i);
+                return true;
+            }
+        }
+
+        return false;
+    }
+};
+
 class QQuickParticleSystem;
 class QQuickParticleAffector;
 class QQuickParticleEmitter;
@@ -110,22 +135,87 @@ private:
 };
 
 class Q_QUICKPARTICLES_PRIVATE_EXPORT QQuickParticleGroupData {
+    class FreeList
+    {
+    public:
+        FreeList()
+            : firstUnused(UINT_MAX)
+            , allocated(0)
+        {}
+
+        void resize(int newSize)
+        {
+            Q_ASSERT(newSize >= 0);
+            int oldSize = isUnused.size();
+            isUnused.resize(newSize, true);
+            if (newSize > oldSize) {
+                if (firstUnused == UINT_MAX) {
+                    firstUnused = oldSize;
+                } else {
+                    firstUnused = std::min(firstUnused, unsigned(oldSize));
+                }
+            } else if (firstUnused >= unsigned(newSize)) {
+                firstUnused = UINT_MAX;
+            }
+        }
+
+        void free(int index)
+        {
+            isUnused.setBit(index);
+            firstUnused = std::min(firstUnused, unsigned(index));
+            --allocated;
+        }
+
+        int count() const
+        { return allocated; }
+
+        bool hasUnusedEntries() const
+        { return firstUnused != UINT_MAX; }
+
+        int alloc()
+        {
+            if (hasUnusedEntries()) {
+                int nextFree = firstUnused;
+                isUnused.clearBit(firstUnused);
+                firstUnused = isUnused.findNext(firstUnused, true, false);
+                if (firstUnused >= unsigned(isUnused.size())) {
+                    firstUnused = UINT_MAX;
+                }
+                ++allocated;
+                return nextFree;
+            } else {
+                return -1;
+            }
+        }
+
+    private:
+        QV4::BitVector isUnused;
+        unsigned firstUnused;
+        int allocated;
+    };
+
+public: // types
+    typedef int ID;
+    enum { InvalidID = -1, DefaultGroupID = 0 };
+
 public:
-    QQuickParticleGroupData(int id, QQuickParticleSystem* sys);
+    QQuickParticleGroupData(const QString &name, QQuickParticleSystem* sys);
     ~QQuickParticleGroupData();
 
-    int size();
+    int size()
+    { return m_size; }
+
     QString name();
 
     void setSize(int newSize);
 
-    int index;
-    QSet<QQuickParticlePainter*> painters;//TODO: What if they are dynamically removed?
+    const ID index;
+    QQuickParticleVarLengthArray<QQuickParticlePainter*, 4> painters;//TODO: What if they are dynamically removed?
 
     //TODO: Refactor particle data list out into a separate class
     QVector<QQuickParticleData*> data;
+    FreeList freeList;
     QQuickParticleDataHeap dataHeap;
-    QSet<int> reusableIndexes;
     bool recycle(); //Force recycling round, returns true if all indexes are now reusable
 
     void initList();
@@ -152,7 +242,7 @@ struct Color4ub {
 class Q_QUICKPARTICLES_PRIVATE_EXPORT QQuickParticleData {
 public:
     //TODO: QObject like memory management (without the cost, just attached to system)
-    QQuickParticleData(QQuickParticleSystem* sys);
+    QQuickParticleData();
     ~QQuickParticleData();
 
     QQuickParticleData(const QQuickParticleData &other);
@@ -162,28 +252,28 @@ public:
     //If setting multiple parameters at once, doing the conversion yourself will be faster.
 
     //sets the x accleration without affecting the instantaneous x velocity or position
-    void setInstantaneousAX(qreal ax);
+    void setInstantaneousAX(float ax, QQuickParticleSystem *particleSystem);
     //sets the x velocity without affecting the instantaneous x postion
-    void setInstantaneousVX(qreal vx);
+    void setInstantaneousVX(float vx, QQuickParticleSystem *particleSystem);
     //sets the instantaneous x postion
-    void setInstantaneousX(qreal x);
+    void setInstantaneousX(float x, QQuickParticleSystem *particleSystem);
     //sets the y accleration without affecting the instantaneous y velocity or position
-    void setInstantaneousAY(qreal ay);
+    void setInstantaneousAY(float ay, QQuickParticleSystem *particleSystem);
     //sets the y velocity without affecting the instantaneous y postion
-    void setInstantaneousVY(qreal vy);
+    void setInstantaneousVY(float vy, QQuickParticleSystem *particleSystem);
     //sets the instantaneous Y postion
-    void setInstantaneousY(qreal y);
+    void setInstantaneousY(float y, QQuickParticleSystem *particleSystem);
 
     //TODO: Slight caching?
-    qreal curX() const;
-    qreal curVX() const;
-    qreal curAX() const { return ax; }
-    qreal curY() const;
-    qreal curVY() const;
-    qreal curAY() const { return ay; }
-
-    QQuickParticleEmitter* e;//### Needed?
-    QQuickParticleSystem* system;
+    float curX(QQuickParticleSystem *particleSystem) const;
+    float curVX(QQuickParticleSystem *particleSystem) const;
+    float curAX() const { return ax; }
+    float curAX(QQuickParticleSystem *) const { return ax; } // used by the macros in qquickv4particledata.cpp
+    float curY(QQuickParticleSystem *particleSystem) const;
+    float curVY(QQuickParticleSystem *particleSystem) const;
+    float curAY() const { return ay; }
+    float curAY(QQuickParticleSystem *) const { return ay; } // used by the macros in qquickv4particledata.cpp
+
     int index;
     int systemIndex;
 
@@ -221,7 +311,7 @@ public:
     float animWidth;
     float animHeight;
 
-    int group;
+    QQuickParticleGroupData::ID groupId;
 
     //Used by ImageParticle data shadowing
     QQuickImageParticle* colorOwner;
@@ -240,14 +330,18 @@ public:
     // 4 bytes wasted
 
 
-    void debugDump();
-    bool stillAlive();//Only checks end, because usually that's all you need and it's a little faster.
-    bool alive();
-    float lifeLeft();
-    float curSize();
+    void debugDump(QQuickParticleSystem *particleSystem) const;
+    bool stillAlive(QQuickParticleSystem *particleSystem) const; //Only checks end, because usually that's all you need and it's a little faster.
+    bool alive(QQuickParticleSystem *particleSystem) const;
+    float lifeLeft(QQuickParticleSystem *particleSystem) const;
+
+    float curSize(QQuickParticleSystem *particleSystem) const;
     void clone(const QQuickParticleData& other);//Not =, leaves meta-data like index
-    QQmlV4Handle v4Value();
-    void extendLife(float time);
+    QQmlV4Handle v4Value(QQuickParticleSystem *particleSystem);
+    void extendLife(float time, QQuickParticleSystem *particleSystem);
+
+    static inline Q_DECL_CONSTEXPR float EPSILON() Q_DECL_NOTHROW { return 0.001f; }
+
 private:
     QQuickV4ParticleData* v8Datum;
 };
@@ -305,7 +399,7 @@ private Q_SLOTS:
 
 public:
     //These can be called multiple times per frame, performance critical
-    void emitParticle(QQuickParticleData* p);
+    void emitParticle(QQuickParticleData* p, QQuickParticleEmitter *particleEmitter);
     QQuickParticleData* newDatum(int groupId, bool respectLimits = true, int sysIdx = -1);
     void finishNewDatum(QQuickParticleData*);
     void moveGroups(QQuickParticleData *d, int newGIdx);
@@ -317,10 +411,13 @@ public:
     //Data members here for ease of related class and auto-test usage. Not "public" API. TODO: d_ptrize
     QSet<QQuickParticleData*> needsReset;
     QVector<QQuickParticleData*> bySysIdx; //Another reference to the data (data owned by group), but by sysIdx
-    QHash<QString, int> groupIds;
-    QHash<int, QQuickParticleGroupData*> groupData;
     QQuickStochasticEngine* stateEngine;
 
+    QHash<QString, int> groupIds;
+    QVarLengthArray<QQuickParticleGroupData*, 32> groupData;
+    int nextFreeGroupId;
+    int registerParticleGroupData(const QString &name, QQuickParticleGroupData *pgd);
+
     //Also only here for auto-test usage
     void updateCurrentTime( int currentTime );
     QQuickParticleSystemAnimation* m_animation;
@@ -333,6 +430,7 @@ public:
 
     void registerParticlePainter(QQuickParticlePainter* p);
     void registerParticleEmitter(QQuickParticleEmitter* e);
+    void finishRegisteringParticleEmitter(QQuickParticleEmitter *e);
     void registerParticleAffector(QQuickParticleAffector* a);
     void registerParticleGroup(QQuickParticleGroup* g);
 
@@ -349,6 +447,9 @@ public:
     }
 
 private:
+    void searchNextFreeGroupId();
+
+private:
     void initializeSystem();
     void initGroups();
     QList<QPointer<QQuickParticleEmitter> > m_emitters;
@@ -356,7 +457,6 @@ private:
     QList<QPointer<QQuickParticlePainter> > m_painters;
     QList<QPointer<QQuickParticlePainter> > m_syncList;
     QList<QQuickParticleGroup*> m_groups;
-    int m_nextGroupId;
     int m_nextIndex;
     QSet<int> m_reusableIndexes;
     bool m_componentComplete;
@@ -391,6 +491,124 @@ private:
     QQuickParticleSystem* m_system;
 };
 
+inline void QQuickParticleData::setInstantaneousAX(float ax, QQuickParticleSystem* particleSystem)
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    float t_sq = t * t;
+    float vx = (this->vx + t * this->ax) - t * ax;
+    float ex = this->x + this->vx * t + 0.5f * this->ax * t_sq;
+    float x = ex - t * vx - 0.5f * t_sq * ax;
+
+    this->ax = ax;
+    this->vx = vx;
+    this->x = x;
+}
+
+inline void QQuickParticleData::setInstantaneousVX(float vx, QQuickParticleSystem* particleSystem)
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    float t_sq = t * t;
+    float evx = vx - t * this->ax;
+    float ex = this->x + this->vx * t + 0.5f * this->ax * t_sq;
+    float x = ex - t * evx - 0.5f * t_sq * this->ax;
+
+    this->vx = evx;
+    this->x = x;
+}
+
+inline void QQuickParticleData::setInstantaneousX(float x, QQuickParticleSystem* particleSystem)
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    float t_sq = t * t;
+    this->x = x - t * this->vx - 0.5f * t_sq * this->ax;
+}
+
+inline void QQuickParticleData::setInstantaneousAY(float ay, QQuickParticleSystem* particleSystem)
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    float t_sq = t * t;
+    float vy = (this->vy + t * this->ay) - t * ay;
+    float ey = this->y + this->vy * t + 0.5f * this->ay * t_sq;
+    float y = ey - t * vy - 0.5f * t_sq * ay;
+
+    this->ay = ay;
+    this->vy = vy;
+    this->y = y;
+}
+
+inline void QQuickParticleData::setInstantaneousVY(float vy, QQuickParticleSystem* particleSystem)
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    float t_sq = t * t;
+    float evy = vy - t * this->ay;
+    float ey = this->y + this->vy * t + 0.5f * this->ay * t_sq;
+    float y = ey - t*evy - 0.5f * t_sq * this->ay;
+
+    this->vy = evy;
+    this->y = y;
+}
+
+inline void QQuickParticleData::setInstantaneousY(float y, QQuickParticleSystem *particleSystem)
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    float t_sq = t * t;
+    this->y = y - t * this->vy - 0.5f * t_sq * this->ay;
+}
+
+inline float QQuickParticleData::curX(QQuickParticleSystem *particleSystem) const
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    float t_sq = t * t;
+    return this->x + this->vx * t + 0.5f * this->ax * t_sq;
+}
+
+inline float QQuickParticleData::curVX(QQuickParticleSystem *particleSystem) const
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    return this->vx + t * this->ax;
+}
+
+inline float QQuickParticleData::curY(QQuickParticleSystem *particleSystem) const
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    float t_sq = t * t;
+    return y + vy * t + 0.5f * ay * t_sq;
+}
+
+inline float QQuickParticleData::curVY(QQuickParticleSystem *particleSystem) const
+{
+    float t = (particleSystem->timeInt / 1000.0f) - this->t;
+    return vy + t*ay;
+}
+
+inline bool QQuickParticleData::stillAlive(QQuickParticleSystem* system) const
+{
+    if (!system)
+        return false;
+    return (t + lifeSpan - EPSILON()) > (system->timeInt / 1000.0f);
+}
+
+inline bool QQuickParticleData::alive(QQuickParticleSystem* system) const
+{
+    if (!system)
+        return false;
+    float st = (system->timeInt / 1000.0f);
+    return (t + EPSILON()) < st && (t + lifeSpan - EPSILON()) > st;
+}
+
+inline float QQuickParticleData::lifeLeft(QQuickParticleSystem *particleSystem) const
+{
+    if (!particleSystem)
+        return 0.0f;
+    return (t + lifeSpan) - (particleSystem->timeInt / 1000.0f);
+}
+
+inline float QQuickParticleData::curSize(QQuickParticleSystem *particleSystem) const
+{
+    if (!particleSystem || lifeSpan == 0.0f)
+        return 0.0f;
+    return size + (endSize - size) * (1 - (lifeLeft(particleSystem) / lifeSpan));
+}
 
 QT_END_NAMESPACE
 
diff --git a/src/particles/qquickpointattractor.cpp b/src/particles/qquickpointattractor.cpp
index 8b3cfbd1ff..779b2915f0 100644
--- a/src/particles/qquickpointattractor.cpp
+++ b/src/particles/qquickpointattractor.cpp
@@ -115,8 +115,8 @@ bool QQuickAttractorAffector::affectParticle(QQuickParticleData *d, qreal dt)
 {
     if (m_strength == 0.0)
         return false;
-    qreal dx = m_x+m_offset.x() - d->curX();
-    qreal dy = m_y+m_offset.y() - d->curY();
+    qreal dx = m_x+m_offset.x() - d->curX(m_system);
+    qreal dy = m_y+m_offset.y() - d->curY(m_system);
     qreal r = std::sqrt((dx*dx) + (dy*dy));
     qreal theta = std::atan2(dy,dx);
     qreal ds = 0;
@@ -146,15 +146,15 @@ bool QQuickAttractorAffector::affectParticle(QQuickParticleData *d, qreal dt)
         d->y = (d->y + dy);
         break;
     case Acceleration:
-        d->setInstantaneousAX(d->ax + dx);
-        d->setInstantaneousAY(d->ay + dy);
+        d->setInstantaneousAX(d->ax + dx, m_system);
+        d->setInstantaneousAY(d->ay + dy, m_system);
         break;
     case Velocity: //also default
     default:
-        vx = d->curVX();
-        vy = d->curVY();
-        d->setInstantaneousVX(vx + dx);
-        d->setInstantaneousVY(vy + dy);
+        vx = d->curVX(m_system);
+        vy = d->curVY(m_system);
+        d->setInstantaneousVX(vx + dx, m_system);
+        d->setInstantaneousVY(vy + dy, m_system);
     }
 
     return true;
diff --git a/src/particles/qquickspritegoal.cpp b/src/particles/qquickspritegoal.cpp
index 7afb787530..5784f1402d 100644
--- a/src/particles/qquickspritegoal.cpp
+++ b/src/particles/qquickspritegoal.cpp
@@ -124,7 +124,7 @@ bool QQuickSpriteGoalAffector::affectParticle(QQuickParticleData *d, qreal dt)
     QQuickStochasticEngine *engine = 0;
     if (!m_systemStates){
         //TODO: Affect all engines
-        foreach (QQuickParticlePainter *p, m_system->groupData[d->group]->painters)
+        foreach (QQuickParticlePainter *p, m_system->groupData[d->groupId]->painters)
             if (qobject_cast<QQuickImageParticle*>(p))
                 engine = qobject_cast<QQuickImageParticle*>(p)->spriteEngine();
     }else{
diff --git a/src/particles/qquicktrailemitter.cpp b/src/particles/qquicktrailemitter.cpp
index 89a68a0356..d4d2adcfb2 100644
--- a/src/particles/qquicktrailemitter.cpp
+++ b/src/particles/qquicktrailemitter.cpp
@@ -179,10 +179,10 @@ void QQuickTrailEmitter::emitWindow(int timeStamp)
     qreal sizeAtEnd = m_particleEndSize >= 0 ? m_particleEndSize : m_particleSize;
 
     int gId = m_system->groupIds[m_follow];
-    int gId2 = m_system->groupIds[m_group];
+    int gId2 = groupId();
     for (int i=0; i<m_system->groupData[gId]->data.count(); i++) {
         QQuickParticleData *d = m_system->groupData[gId]->data[i];
-        if (!d->stillAlive()){
+        if (!d->stillAlive(m_system)){
             m_lastEmission[i] = time; //Should only start emitting when it returns to life
             continue;
         }
@@ -192,7 +192,8 @@ void QQuickTrailEmitter::emitWindow(int timeStamp)
         if (pt + maxLife < time)//We missed so much, that we should skip emiting particles that are dead by now
             pt = time - maxLife;
 
-        if ((width() || height()) && !effectiveExtruder()->contains(QRectF(offset.x(), offset.y(), width(), height()),QPointF(d->curX(), d->curY()))){
+        if ((width() || height()) && !effectiveExtruder()->contains(QRectF(offset.x(), offset.y(), width(), height()),
+                                                                    QPointF(d->curX(m_system), d->curY(m_system)))) {
             m_lastEmission[d->index] = time;//jump over this time period without emitting, because it's outside
             continue;
         }
@@ -202,8 +203,6 @@ void QQuickTrailEmitter::emitWindow(int timeStamp)
         while (pt < time || !m_burstQueue.isEmpty()){
             QQuickParticleData* datum = m_system->newDatum(gId2, !m_overwrite);
             if (datum){//else, skip this emission
-                datum->e = this;//###useful?
-
                 // Particle timestamp
                 datum->t = pt;
                 datum->lifeSpan =
@@ -215,8 +214,8 @@ void QQuickTrailEmitter::emitWindow(int timeStamp)
                 // Note that burst location doesn't get used for follow emitter
                 qreal followT =  pt - d->t;
                 qreal followT2 = followT * followT * 0.5;
-                qreal eW = m_emitterXVariation < 0 ? d->curSize() : m_emitterXVariation;
-                qreal eH = m_emitterYVariation < 0 ? d->curSize() : m_emitterYVariation;
+                qreal eW = m_emitterXVariation < 0 ? d->curSize(m_system) : m_emitterXVariation;
+                qreal eH = m_emitterYVariation < 0 ? d->curSize(m_system) : m_emitterYVariation;
                 //Subtract offset, because PS expects this in emitter coordinates
                 QRectF boundsRect(d->x - offset.x() + d->vx * followT + d->ax * followT2 - eW/2,
                                   d->y - offset.y() + d->vy * followT + d->ay * followT2 - eH/2,
@@ -251,7 +250,7 @@ void QQuickTrailEmitter::emitWindow(int timeStamp)
 
                 toEmit << datum;
 
-                m_system->emitParticle(datum);
+                m_system->emitParticle(datum, this);
             }
             if (!m_burstQueue.isEmpty()){
                 m_burstQueue.first().first--;
@@ -263,7 +262,7 @@ void QQuickTrailEmitter::emitWindow(int timeStamp)
         }
 
         foreach (QQuickParticleData* d, toEmit)
-            m_system->emitParticle(d);
+            m_system->emitParticle(d, this);
 
         if (isEmitConnected() || isEmitFollowConnected()) {
             QQmlEngine *qmlEngine = ::qmlEngine(this);
@@ -273,10 +272,10 @@ void QQuickTrailEmitter::emitWindow(int timeStamp)
             QV4::ScopedArrayObject array(scope, v4->newArrayObject(toEmit.size()));
             QV4::ScopedValue v(scope);
             for (int i=0; i<toEmit.size(); i++)
-                array->putIndexed(i, (v = toEmit[i]->v4Value()));
+                array->putIndexed(i, (v = toEmit[i]->v4Value(m_system)));
 
             if (isEmitFollowConnected())
-                emitFollowParticles(QQmlV4Handle(array), d->v4Value());//A chance for many arbitrary JS changes
+                emitFollowParticles(QQmlV4Handle(array), d->v4Value(m_system));//A chance for many arbitrary JS changes
             else if (isEmitConnected())
                 emitParticles(QQmlV4Handle(array));//A chance for arbitrary JS changes
         }
diff --git a/src/particles/qquickturbulence.cpp b/src/particles/qquickturbulence.cpp
index 154235441b..74558413a6 100644
--- a/src/particles/qquickturbulence.cpp
+++ b/src/particles/qquickturbulence.cpp
@@ -181,12 +181,12 @@ void QQuickTurbulenceAffector::affectSystem(qreal dt)
 
     QRect boundsRect(0,0,m_gridSize,m_gridSize);
     foreach (QQuickParticleGroupData *gd, m_system->groupData){
-        if (!activeGroup(m_system->groupData.key(gd)))
+        if (!activeGroup(gd->index))
             continue;
         foreach (QQuickParticleData *d, gd->data){
             if (!shouldAffect(d))
                 continue;
-            QPoint pos = (QPointF(d->curX(), d->curY()) - m_offset).toPoint();
+            QPoint pos = (QPointF(d->curX(m_system), d->curY(m_system)) - m_offset).toPoint();
             if (!boundsRect.contains(pos,true))//Need to redo bounds checking due to quantization.
                 continue;
             qreal fx = 0.0;
@@ -194,8 +194,8 @@ void QQuickTurbulenceAffector::affectSystem(qreal dt)
             fx += m_vectorField[pos.x()][pos.y()].x() * m_strength;
             fy += m_vectorField[pos.x()][pos.y()].y() * m_strength;
             if (fx || fy){
-                d->setInstantaneousVX(d->curVX()+ fx * dt);
-                d->setInstantaneousVY(d->curVY()+ fy * dt);
+                d->setInstantaneousVX(d->curVX(m_system)+ fx * dt, m_system);
+                d->setInstantaneousVY(d->curVY(m_system)+ fy * dt, m_system);
                 postAffect(d);
             }
         }
diff --git a/src/particles/qquickv4particledata.cpp b/src/particles/qquickv4particledata.cpp
index 86e3c91ba8..3d7f4ce5b8 100644
--- a/src/particles/qquickv4particledata.cpp
+++ b/src/particles/qquickv4particledata.cpp
@@ -272,11 +272,13 @@ QT_BEGIN_NAMESPACE
 struct QV4ParticleData : public QV4::Object
 {
     struct Data : QV4::Object::Data {
-        Data(QQuickParticleData *datum)
+        Data(QQuickParticleData *datum, QQuickParticleSystem* particleSystem)
             : datum(datum)
+            , particleSystem(particleSystem)
         {
         }
         QQuickParticleData* datum;//TODO: Guard needed?
+        QQuickParticleSystem* particleSystem;
     };
     V4_OBJECT(QV4::Object)
 };
@@ -312,7 +314,7 @@ static QV4::ReturnedValue particleData_lifeLeft(QV4::CallContext *ctx)
     if (!r || !r->d()->datum)
         return ctx->engine()->throwError(QStringLiteral("Not a valid ParticleData object"));
 
-    return QV4::Encode(r->d()->datum->lifeLeft());
+    return QV4::Encode(r->d()->datum->lifeLeft(r->d()->particleSystem));
 }
 
 static QV4::ReturnedValue particleData_curSize(QV4::CallContext *ctx)
@@ -323,7 +325,7 @@ static QV4::ReturnedValue particleData_curSize(QV4::CallContext *ctx)
     if (!r || !r->d()->datum)
         return ctx->engine()->throwError(QStringLiteral("Not a valid ParticleData object"));
 
-    return QV4::Encode(r->d()->datum->curSize());
+    return QV4::Encode(r->d()->datum->curSize(r->d()->particleSystem));
 }
 #define COLOR_GETTER_AND_SETTER(VAR, NAME) static QV4::ReturnedValue particleData_get_ ## NAME (QV4::CallContext *ctx) \
 { \
@@ -397,7 +399,7 @@ static QV4::ReturnedValue particleData_set_ ## VARIABLE (QV4::CallContext *ctx)\
     if (!r || !r->d()->datum) \
         ctx->engine()->throwError(QStringLiteral("Not a valid ParticleData object")); \
 \
-    return QV4::Encode(r->d()->datum-> GETTER ());\
+    return QV4::Encode(r->d()->datum-> GETTER (r->d()->particleSystem));\
 }\
 \
 static QV4::ReturnedValue particleData_set_ ## VARIABLE (QV4::CallContext *ctx)\
@@ -407,7 +409,7 @@ static QV4::ReturnedValue particleData_set_ ## VARIABLE (QV4::CallContext *ctx)\
     if (!r || !r->d()->datum)\
         ctx->engine()->throwError(QStringLiteral("Not a valid ParticleData object"));\
 \
-    r->d()->datum-> SETTER (ctx->argc() ? ctx->args()[0].toNumber() : qQNaN());\
+    r->d()->datum-> SETTER (ctx->argc() ? ctx->args()[0].toNumber() : qQNaN(), r->d()->particleSystem);\
     return QV4::Encode::undefined(); \
 }
 
@@ -503,7 +505,7 @@ QV4ParticleDataDeletable::~QV4ParticleDataDeletable()
 V4_DEFINE_EXTENSION(QV4ParticleDataDeletable, particleV4Data);
 
 
-QQuickV4ParticleData::QQuickV4ParticleData(QV8Engine* engine, QQuickParticleData* datum)
+QQuickV4ParticleData::QQuickV4ParticleData(QV8Engine* engine, QQuickParticleData* datum, QQuickParticleSystem *system)
 {
     if (!engine || !datum)
         return;
@@ -511,7 +513,7 @@ QQuickV4ParticleData::QQuickV4ParticleData(QV8Engine* engine, QQuickParticleData
     QV4::ExecutionEngine *v4 = QV8Engine::getV4(engine);
     QV4::Scope scope(v4);
     QV4ParticleDataDeletable *d = particleV4Data(scope.engine);
-    QV4::ScopedObject o(scope, v4->memoryManager->allocObject<QV4ParticleData>(datum));
+    QV4::ScopedObject o(scope, v4->memoryManager->allocObject<QV4ParticleData>(datum, system));
     QV4::ScopedObject p(scope, d->proto.value());
     o->setPrototype(p);
     m_v4Value = o;
diff --git a/src/particles/qquickv4particledata_p.h b/src/particles/qquickv4particledata_p.h
index b93c0333d7..0d88f0f9cc 100644
--- a/src/particles/qquickv4particledata_p.h
+++ b/src/particles/qquickv4particledata_p.h
@@ -58,9 +58,10 @@
 QT_BEGIN_NAMESPACE
 
 class QQuickParticleData;
+class QQuickParticleSystem;
 class QQuickV4ParticleData {
 public:
-    QQuickV4ParticleData(QV8Engine*,QQuickParticleData*);
+    QQuickV4ParticleData(QV8Engine*, QQuickParticleData*, QQuickParticleSystem *system);
     ~QQuickV4ParticleData();
     QQmlV4Handle v4Value();
 private:
diff --git a/src/particles/qquickwander.cpp b/src/particles/qquickwander.cpp
index 862c796dac..09d36ab2e8 100644
--- a/src/particles/qquickwander.cpp
+++ b/src/particles/qquickwander.cpp
@@ -151,29 +151,29 @@ bool QQuickWanderAffector::affectParticle(QQuickParticleData* data, qreal dt)
     qreal newX, newY;
     switch (m_affectedParameter){
     case Position:
-        newX = data->curX() + dx;
+        newX = data->curX(m_system) + dx;
         if (m_xVariance > qAbs(newX) )
             data->x += dx;
-        newY = data->curY() + dy;
+        newY = data->curY(m_system) + dy;
         if (m_yVariance > qAbs(newY) )
             data->y += dy;
         break;
     default:
     case Velocity:
-        newX = data->curVX() + dx;
-        if (m_xVariance > qAbs(newX) )
-            data->setInstantaneousVX(newX);
-        newY = data->curVY() + dy;
-        if (m_yVariance > qAbs(newY) )
-            data->setInstantaneousVY(newY);
+        newX = data->curVX(m_system) + dx;
+        if (m_xVariance > qAbs(newX))
+            data->setInstantaneousVX(newX, m_system);
+        newY = data->curVY(m_system) + dy;
+        if (m_yVariance > qAbs(newY))
+            data->setInstantaneousVY(newY, m_system);
         break;
     case Acceleration:
         newX = data->ax + dx;
-        if (m_xVariance > qAbs(newX) )
-            data->setInstantaneousAX(newX);
+        if (m_xVariance > qAbs(newX))
+            data->setInstantaneousAX(newX, m_system);
         newY = data->ay + dy;
-        if (m_yVariance > qAbs(newY) )
-            data->setInstantaneousAY(newY);
+        if (m_yVariance > qAbs(newY))
+            data->setInstantaneousAY(newY, m_system);
         break;
     }
     return true;
diff --git a/src/plugins/qmltooling/packetprotocol/qpacket.cpp b/src/plugins/qmltooling/packetprotocol/qpacket.cpp
index c42288e920..fab0a5b189 100644
--- a/src/plugins/qmltooling/packetprotocol/qpacket.cpp
+++ b/src/plugins/qmltooling/packetprotocol/qpacket.cpp
@@ -108,11 +108,34 @@ QPacket::QPacket(int version, const QByteArray &data)
 }
 
 /*!
-  Returns raw packet data.
+  Returns a reference to the raw packet data.
   */
-QByteArray QPacket::data() const
+const QByteArray &QPacket::data() const
 {
     return buf.data();
 }
 
+/*!
+  Returns a copy of the raw packet data, with extra reserved space removed.
+  Mind that this triggers a deep copy. Use it if you anticipate the data to be detached soon anyway.
+  */
+QByteArray QPacket::squeezedData() const
+{
+    QByteArray ret = buf.data();
+    ret.squeeze();
+    return ret;
+}
+
+/*!
+  Clears the packet, discarding any data.
+ */
+void QPacket::clear()
+{
+    buf.reset();
+    QByteArray &buffer = buf.buffer();
+    // Keep the old size to prevent unnecessary allocations
+    buffer.reserve(buffer.capacity());
+    buffer.truncate(0);
+}
+
 QT_END_NAMESPACE
diff --git a/src/plugins/qmltooling/packetprotocol/qpacket_p.h b/src/plugins/qmltooling/packetprotocol/qpacket_p.h
index a079b244e8..b6fda2411d 100644
--- a/src/plugins/qmltooling/packetprotocol/qpacket_p.h
+++ b/src/plugins/qmltooling/packetprotocol/qpacket_p.h
@@ -61,7 +61,9 @@ class QPacket : public QDataStream
 public:
     QPacket(int version);
     explicit QPacket(int version, const QByteArray &ba);
-    QByteArray data() const;
+    const QByteArray &data() const;
+    QByteArray squeezedData() const;
+    void clear();
 
 private:
     void init(QIODevice::OpenMode mode);
diff --git a/src/plugins/qmltooling/qmldbg_profiler/qqmlprofileradapter.cpp b/src/plugins/qmltooling/qmldbg_profiler/qqmlprofileradapter.cpp
index e89d87e76b..688ced26ec 100644
--- a/src/plugins/qmltooling/qmldbg_profiler/qqmlprofileradapter.cpp
+++ b/src/plugins/qmltooling/qmldbg_profiler/qqmlprofileradapter.cpp
@@ -67,7 +67,7 @@ QQmlProfilerAdapter::QQmlProfilerAdapter(QQmlProfilerService *service, QQmlEngin
 //     (see tst_qqmldebugtrace::trace() benchmark)
 static void qQmlProfilerDataToByteArrays(const QQmlProfilerData *d, QList<QByteArray> &messages)
 {
-    QByteArray data;
+    QQmlDebugPacket ds;
     Q_ASSERT_X(((d->messageType | d->detailType) & (1 << 31)) == 0, Q_FUNC_INFO,
                "You can use at most 31 message types and 31 detail types.");
     for (uint decodedMessageType = 0; (d->messageType >> decodedMessageType) != 0;
@@ -81,7 +81,6 @@ static void qQmlProfilerDataToByteArrays(const QQmlProfilerData *d, QList<QByteA
                 continue;
 
             //### using QDataStream is relatively expensive
-            QQmlDebugPacket ds;
             ds << d->time << decodedMessageType << decodedDetailType;
 
             switch (decodedMessageType) {
@@ -99,7 +98,8 @@ static void qQmlProfilerDataToByteArrays(const QQmlProfilerData *d, QList<QByteA
                 Q_ASSERT_X(false, Q_FUNC_INFO, "Invalid message type.");
                 break;
             }
-            messages << ds.data();
+            messages.append(ds.squeezedData());
+            ds.clear();
         }
     }
 }
@@ -107,7 +107,7 @@ static void qQmlProfilerDataToByteArrays(const QQmlProfilerData *d, QList<QByteA
 qint64 QQmlProfilerAdapter::sendMessages(qint64 until, QList<QByteArray> &messages)
 {
     while (next != data.length()) {
-        if (data[next].time > until)
+        if (data[next].time > until || messages.length() > s_numMessagesPerBatch)
             return data[next].time;
         qQmlProfilerDataToByteArrays(&(data[next++]), messages);
     }
diff --git a/src/plugins/qmltooling/qmldbg_profiler/qqmlprofilerservice.cpp b/src/plugins/qmltooling/qmldbg_profiler/qqmlprofilerservice.cpp
index fc2ba1e094..9e1c8af3e6 100644
--- a/src/plugins/qmltooling/qmldbg_profiler/qqmlprofilerservice.cpp
+++ b/src/plugins/qmltooling/qmldbg_profiler/qqmlprofilerservice.cpp
@@ -342,12 +342,15 @@ void QQmlProfilerServiceImpl::sendMessages()
     while (!m_startTimes.empty()) {
         QQmlAbstractProfilerAdapter *first = m_startTimes.begin().value();
         m_startTimes.erase(m_startTimes.begin());
-        if (!m_startTimes.empty()) {
-            qint64 next = first->sendMessages(m_startTimes.begin().key(), messages);
-            if (next != -1)
-                m_startTimes.insert(next, first);
-        } else {
-            first->sendMessages(std::numeric_limits<qint64>::max(), messages);
+        qint64 next = first->sendMessages(m_startTimes.isEmpty() ?
+                                              std::numeric_limits<qint64>::max() :
+                                              m_startTimes.begin().key(), messages);
+        if (next != -1)
+            m_startTimes.insert(next, first);
+
+        if (messages.length() >= QQmlAbstractProfilerAdapter::s_numMessagesPerBatch) {
+            emit messagesToClient(name(), messages);
+            messages.clear();
         }
     }
 
diff --git a/src/plugins/qmltooling/qmldbg_profiler/qv4profileradapter.cpp b/src/plugins/qmltooling/qmldbg_profiler/qv4profileradapter.cpp
index ffacc58817..b50eef5545 100644
--- a/src/plugins/qmltooling/qmldbg_profiler/qv4profileradapter.cpp
+++ b/src/plugins/qmltooling/qmldbg_profiler/qv4profileradapter.cpp
@@ -39,7 +39,6 @@
 
 #include "qv4profileradapter.h"
 #include "qqmlprofilerservice.h"
-#include "qqmldebugpacket.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -68,27 +67,28 @@ QV4ProfilerAdapter::QV4ProfilerAdapter(QQmlProfilerService *service, QV4::Execut
                                    QVector<QV4::Profiling::MemoryAllocationProperties>)));
 }
 
-qint64 QV4ProfilerAdapter::appendMemoryEvents(qint64 until, QList<QByteArray> &messages)
+qint64 QV4ProfilerAdapter::appendMemoryEvents(qint64 until, QList<QByteArray> &messages,
+                                              QQmlDebugPacket &d)
 {
     while (m_memoryData.length() > m_memoryPos && m_memoryData[m_memoryPos].timestamp <= until) {
-        QQmlDebugPacket d;
         QV4::Profiling::MemoryAllocationProperties &props = m_memoryData[m_memoryPos];
         d << props.timestamp << MemoryAllocation << props.type << props.size;
         ++m_memoryPos;
-        messages.append(d.data());
+        messages.append(d.squeezedData());
+        d.clear();
     }
     return m_memoryData.length() == m_memoryPos ? -1 : m_memoryData[m_memoryPos].timestamp;
 }
 
 qint64 QV4ProfilerAdapter::finalizeMessages(qint64 until, QList<QByteArray> &messages,
-                                            qint64 callNext)
+                                            qint64 callNext, QQmlDebugPacket &d)
 {
     if (callNext == -1) {
         m_functionCallData.clear();
         m_functionCallPos = 0;
     }
 
-    qint64 memoryNext = appendMemoryEvents(until, messages);
+    qint64 memoryNext = appendMemoryEvents(until, messages, d);
 
     if (memoryNext == -1) {
         m_memoryData.clear();
@@ -101,42 +101,43 @@ qint64 QV4ProfilerAdapter::finalizeMessages(qint64 until, QList<QByteArray> &mes
 
 qint64 QV4ProfilerAdapter::sendMessages(qint64 until, QList<QByteArray> &messages)
 {
+    QQmlDebugPacket d;
     while (true) {
         while (!m_stack.isEmpty() &&
                (m_functionCallPos == m_functionCallData.length() ||
                 m_stack.top() <= m_functionCallData[m_functionCallPos].start)) {
-            if (m_stack.top() > until)
-                return finalizeMessages(until, messages, m_stack.top());
+            if (m_stack.top() > until || messages.length() > s_numMessagesPerBatch)
+                return finalizeMessages(until, messages, m_stack.top(), d);
 
-            appendMemoryEvents(m_stack.top(), messages);
-            QQmlDebugPacket d;
+            appendMemoryEvents(m_stack.top(), messages, d);
             d << m_stack.pop() << RangeEnd << Javascript;
-            messages.append(d.data());
+            messages.append(d.squeezedData());
+            d.clear();
         }
         while (m_functionCallPos != m_functionCallData.length() &&
                (m_stack.empty() || m_functionCallData[m_functionCallPos].start < m_stack.top())) {
             const QV4::Profiling::FunctionCallProperties &props =
                     m_functionCallData[m_functionCallPos];
-            if (props.start > until)
-                return finalizeMessages(until, messages, props.start);
-
-            appendMemoryEvents(props.start, messages);
-
-            QQmlDebugPacket d_start;
-            d_start << props.start << RangeStart << Javascript;
-            messages.push_back(d_start.data());
-            QQmlDebugPacket d_location;
-            d_location << props.start << RangeLocation << Javascript << props.file << props.line
-                       << props.column;
-            messages.push_back(d_location.data());
-            QQmlDebugPacket d_data;
-            d_data << props.start << RangeData << Javascript << props.name;
-            messages.push_back(d_data.data());
+            if (props.start > until || messages.length() > s_numMessagesPerBatch)
+                return finalizeMessages(until, messages, props.start, d);
+
+            appendMemoryEvents(props.start, messages, d);
+
+            d << props.start << RangeStart << Javascript;
+            messages.push_back(d.squeezedData());
+            d.clear();
+            d << props.start << RangeLocation << Javascript << props.file << props.line
+              << props.column;
+            messages.push_back(d.squeezedData());
+            d.clear();
+            d << props.start << RangeData << Javascript << props.name;
+            messages.push_back(d.squeezedData());
+            d.clear();
             m_stack.push(props.end);
             ++m_functionCallPos;
         }
         if (m_stack.empty() && m_functionCallPos == m_functionCallData.length())
-            return finalizeMessages(until, messages, -1);
+            return finalizeMessages(until, messages, -1, d);
     }
 }
 
diff --git a/src/plugins/qmltooling/qmldbg_profiler/qv4profileradapter.h b/src/plugins/qmltooling/qmldbg_profiler/qv4profileradapter.h
index 303ccab72c..f2985af98b 100644
--- a/src/plugins/qmltooling/qmldbg_profiler/qv4profileradapter.h
+++ b/src/plugins/qmltooling/qmldbg_profiler/qv4profileradapter.h
@@ -53,6 +53,7 @@
 
 #include <private/qv4profiling_p.h>
 #include <private/qqmlabstractprofileradapter_p.h>
+#include "qqmldebugpacket.h"
 
 #include <QStack>
 #include <QList>
@@ -86,8 +87,9 @@ private:
     int m_functionCallPos;
     int m_memoryPos;
     QStack<qint64> m_stack;
-    qint64 appendMemoryEvents(qint64 until, QList<QByteArray> &messages);
-    qint64 finalizeMessages(qint64 until, QList<QByteArray> &messages, qint64 callNext);
+    qint64 appendMemoryEvents(qint64 until, QList<QByteArray> &messages, QQmlDebugPacket &d);
+    qint64 finalizeMessages(qint64 until, QList<QByteArray> &messages, qint64 callNext,
+                            QQmlDebugPacket &d);
 
     static quint64 translateFeatures(quint64 qmlFeatures);
 };
diff --git a/src/plugins/qmltooling/qmldbg_quickprofiler/qquickprofileradapter.cpp b/src/plugins/qmltooling/qmldbg_quickprofiler/qquickprofileradapter.cpp
index 5ca64fda15..9a2afd367d 100644
--- a/src/plugins/qmltooling/qmldbg_quickprofiler/qquickprofileradapter.cpp
+++ b/src/plugins/qmltooling/qmldbg_quickprofiler/qquickprofileradapter.cpp
@@ -79,6 +79,7 @@ QQuickProfilerAdapter::~QQuickProfilerAdapter()
 static void qQuickProfilerDataToByteArrays(const QQuickProfilerData &data,
                                            QList<QByteArray> &messages)
 {
+    QQmlDebugPacket ds;
     Q_ASSERT_X(((data.messageType | data.detailType) & (1 << 31)) == 0, Q_FUNC_INFO,
                "You can use at most 31 message types and 31 detail types.");
     for (uint decodedMessageType = 0; (data.messageType >> decodedMessageType) != 0;
@@ -91,8 +92,6 @@ static void qQuickProfilerDataToByteArrays(const QQuickProfilerData &data,
             if ((data.detailType & (1 << decodedDetailType)) == 0)
                 continue;
 
-            //### using QDataStream is relatively expensive
-            QQmlDebugPacket ds;
             ds << data.time << decodedMessageType << decodedDetailType;
 
             switch (decodedMessageType) {
@@ -145,7 +144,8 @@ static void qQuickProfilerDataToByteArrays(const QQuickProfilerData &data,
                 Q_ASSERT_X(false, Q_FUNC_INFO, "Invalid message type.");
                 break;
             }
-            messages << ds.data();
+            messages.append(ds.squeezedData());
+            ds.clear();
         }
     }
 }
@@ -153,7 +153,7 @@ static void qQuickProfilerDataToByteArrays(const QQuickProfilerData &data,
 qint64 QQuickProfilerAdapter::sendMessages(qint64 until, QList<QByteArray> &messages)
 {
     while (next < m_data.size()) {
-        if (m_data[next].time <= until)
+        if (m_data[next].time <= until && messages.length() <= s_numMessagesPerBatch)
             qQuickProfilerDataToByteArrays(m_data[next++], messages);
         else
             return m_data[next].time;
diff --git a/src/plugins/qmltooling/qmldbg_server/qqmldebugserver.cpp b/src/plugins/qmltooling/qmldbg_server/qqmldebugserver.cpp
index a5f9ed9a1a..bc259afaa4 100644
--- a/src/plugins/qmltooling/qmldbg_server/qqmldebugserver.cpp
+++ b/src/plugins/qmltooling/qmldbg_server/qqmldebugserver.cpp
@@ -186,6 +186,7 @@ private:
     QStringList m_clientPlugins;
     bool m_gotHello;
     bool m_blockingMode;
+    bool m_clientSupportsMultiPackets;
 
     QHash<QJSEngine *, EngineCondition> m_engineConditions;
 
@@ -274,7 +275,8 @@ static void cleanupOnShutdown()
 QQmlDebugServerImpl::QQmlDebugServerImpl() :
     m_connection(0),
     m_gotHello(false),
-    m_blockingMode(false)
+    m_blockingMode(false),
+    m_clientSupportsMultiPackets(false)
 {
     static bool postRoutineAdded = false;
     if (!postRoutineAdded) {
@@ -327,7 +329,6 @@ bool QQmlDebugServerImpl::open(const QVariantHash &configuration = QVariantHash(
     return true;
 }
 
-#define qUsage qWarning().noquote().nospace
 void QQmlDebugServerImpl::parseArguments()
 {
     // format: qmljsdebugger=port:<port_from>[,port_to],host:<ip address>][,block]
@@ -376,8 +377,9 @@ void QQmlDebugServerImpl::parseArguments()
         } else if (!services.isEmpty()) {
             services.append(strArgument);
         } else {
-            qUsage() << tr("QML Debugger: Invalid argument \"%1\" detected. Ignoring the same.")
-                        .arg(strArgument);
+            const QString message = tr("QML Debugger: Invalid argument \"%1\" detected."
+                                       " Ignoring the same.").arg(strArgument);
+            qWarning("%s", qPrintable(message));
         }
     }
 
@@ -389,43 +391,47 @@ void QQmlDebugServerImpl::parseArguments()
         else
             m_thread.setPortRange(portFrom, portTo, hostAddress);
     } else {
-        qUsage() << tr("QML Debugger: Ignoring \"-qmljsdebugger=%1\".").arg(args);
-        qUsage() << tr("The format is \"-qmljsdebugger=[file:<file>|port:<port_from>][,<port_to>]"
-                       "[,host:<ip address>][,block][,services:<service>][,<service>]*\"\n");
-        qUsage() << tr("\"file:\" can be used to specify the name of a file the debugger will try "
-                       "to connect to using a QLocalSocket. If \"file:\" is given any \"host:\" and"
-                       "\"port:\" arguments will be ignored.\n");
-        qUsage() << tr("\"host:\" and \"port:\" can be used to specify an address and a single "
-                       "port or a range of ports the debugger will try to bind to with a "
-                       "QTcpServer.\n");
-        qUsage() << tr("\"block\" makes the debugger and some services wait for clients to be "
-                       "connected and ready before the first QML engine starts.\n");
-        qUsage() << tr("\"services:\" can be used to specify which debug services the debugger "
-                       "should load. Some debug services interact badly with others. The V4 "
-                       "debugger should not be loaded when using the QML profiler as it will force "
-                       "any V4 engines to use the JavaScript interpreter rather than the JIT. The "
-                       "following debug services are available by default:");
-        qUsage() << QQmlEngineDebugService::s_key << tr("\t- The QML debugger");
-        qUsage() << QV4DebugService::s_key        << tr("\t- The V4 debugger");
-        qUsage() << QQmlInspectorService::s_key   << tr("\t- The QML inspector");
-        qUsage() << QQmlProfilerService::s_key    << tr("\t- The QML profiler");
-        qUsage() << QQmlEngineControlService::s_key
-                             << tr("\t- Allows the client to delay the starting and stopping of\n"
-                                   "\t\t  QML engines until other services are ready. QtCreator\n"
-                                   "\t\t  uses this service with the QML profiler in order to\n"
-                                   "\t\t  profile multiple QML engines at the same time.");
-        qUsage() << QDebugMessageService::s_key
-                             << tr("\t- Sends qDebug() and similar messages over the QML debug\n"
-                                   "\t\t  connection. QtCreator uses this for showing debug\n"
-                                   "\t\t  messages in the JavaScript console.");
-        qUsage() << tr("Other services offered by qmltooling plugins that implement "
-                       "QQmlDebugServiceFactory and which can be found in the standard plugin "
-                       "paths will also be available and can be specified. If no \"services\" "
-                       "argument is given, all services found this way, including the default "
-                       "ones, are loaded.");
+        QString usage;
+        QTextStream str(&usage);
+        str << tr("QML Debugger: Ignoring \"-qmljsdebugger=%1\".").arg(args) << '\n'
+            << tr("The format is \"-qmljsdebugger=[file:<file>|port:<port_from>][,<port_to>]"
+                  "[,host:<ip address>][,block][,services:<service>][,<service>]*\"") << '\n'
+            << tr("\"file:\" can be used to specify the name of a file the debugger will try "
+                  "to connect to using a QLocalSocket. If \"file:\" is given any \"host:\" and"
+                  "\"port:\" arguments will be ignored.") << '\n'
+            << tr("\"host:\" and \"port:\" can be used to specify an address and a single "
+                  "port or a range of ports the debugger will try to bind to with a "
+                  "QTcpServer.") << '\n'
+            << tr("\"block\" makes the debugger and some services wait for clients to be "
+                  "connected and ready before the first QML engine starts.") << '\n'
+            << tr("\"services:\" can be used to specify which debug services the debugger "
+                  "should load. Some debug services interact badly with others. The V4 "
+                  "debugger should not be loaded when using the QML profiler as it will force "
+                  "any V4 engines to use the JavaScript interpreter rather than the JIT. The "
+                  "following debug services are available by default:") << '\n'
+            << QQmlEngineDebugService::s_key   << "\t- " << tr("The QML debugger") << '\n'
+            << QV4DebugService::s_key          << "\t- " << tr("The V4 debugger") << '\n'
+            << QQmlInspectorService::s_key     << "\t- " << tr("The QML inspector") << '\n'
+            << QQmlProfilerService::s_key      << "\t- " << tr("The QML profiler") << '\n'
+            << QQmlEngineControlService::s_key << "\t- "
+            //: Please preserve the line breaks and formatting
+            << tr("Allows the client to delay the starting and stopping of\n"
+                  "\t\t  QML engines until other services are ready. QtCreator\n"
+                  "\t\t  uses this service with the QML profiler in order to\n"
+                  "\t\t  profile multiple QML engines at the same time.")
+            << '\n' << QDebugMessageService::s_key << "\t- "
+            //: Please preserve the line breaks and formatting
+            << tr("Sends qDebug() and similar messages over the QML debug\n"
+               "\t\t  connection. QtCreator uses this for showing debug\n"
+               "\t\t  messages in the JavaScript console.") << '\n'
+           << tr("Other services offered by qmltooling plugins that implement "
+                 "QQmlDebugServiceFactory and which can be found in the standard plugin "
+                 "paths will also be available and can be specified. If no \"services\" "
+                 "argument is given, all services found this way, including the default "
+                 "ones, are loaded.");
+        qWarning("%s", qPrintable(usage));
     }
 }
-#undef qUsage
 
 void QQmlDebugServerImpl::receiveMessage()
 {
@@ -456,6 +462,11 @@ void QQmlDebugServerImpl::receiveMessage()
                     s_dataStreamVersion = QDataStream::Qt_DefaultCompiledVersion;
             }
 
+            if (!in.atEnd())
+                in >> m_clientSupportsMultiPackets;
+            else
+                m_clientSupportsMultiPackets = false;
+
             // Send the hello answer immediately, since it needs to arrive before
             // the plugins below start sending messages.
 
@@ -516,14 +527,16 @@ void QQmlDebugServerImpl::receiveMessage()
 
     } else {
         if (m_gotHello) {
-            QByteArray message;
-            in >> message;
-
             QHash<QString, QQmlDebugService *>::Iterator iter = m_plugins.find(name);
             if (iter == m_plugins.end()) {
                 qWarning() << "QML Debugger: Message received for missing plugin" << name << '.';
             } else {
-                (*iter)->messageReceived(message);
+                QQmlDebugService *service = *iter;
+                QByteArray message;
+                while (!in.atEnd()) {
+                    in >> message;
+                    service->messageReceived(message);
+                }
             }
         } else {
             qWarning("QML Debugger: Invalid hello message.");
@@ -686,8 +699,16 @@ void QQmlDebugServerImpl::sendMessage(const QString &name, const QByteArray &mes
 void QQmlDebugServerImpl::sendMessages(const QString &name, const QList<QByteArray> &messages)
 {
     if (canSendMessage(name)) {
-        foreach (const QByteArray &message, messages)
-            doSendMessage(name, message);
+        if (m_clientSupportsMultiPackets) {
+            QQmlDebugPacket out;
+            out << name;
+            foreach (const QByteArray &message, messages)
+                out << message;
+            m_protocol->send(out.data());
+        } else {
+            foreach (const QByteArray &message, messages)
+                doSendMessage(name, message);
+        }
         m_connection->flush();
     }
 }
diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index a34c1cbf0e..1960f1d65b 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -1589,7 +1589,9 @@ enum MetaObjectResolverFlags {
 
 static void initMetaObjectResolver(QV4::IR::MemberExpressionResolver *resolver, QQmlPropertyCache *metaObject);
 
-static QV4::IR::Type resolveQmlType(QQmlEnginePrivate *qmlEngine, QV4::IR::MemberExpressionResolver *resolver, QV4::IR::Member *member)
+static QV4::IR::DiscoveredType resolveQmlType(QQmlEnginePrivate *qmlEngine,
+                                              const QV4::IR::MemberExpressionResolver *resolver,
+                                              QV4::IR::Member *member)
 {
     QV4::IR::Type result = QV4::IR::VarType;
 
@@ -1600,7 +1602,6 @@ static QV4::IR::Type resolveQmlType(QQmlEnginePrivate *qmlEngine, QV4::IR::Membe
         int value = type->enumValue(qmlEngine, *member->name, &ok);
         if (ok) {
             member->setEnumValue(value);
-            resolver->clear();
             return QV4::IR::SInt32Type;
         }
     }
@@ -1611,25 +1612,30 @@ static QV4::IR::Type resolveQmlType(QQmlEnginePrivate *qmlEngine, QV4::IR::Membe
         tdata->release(); // Decrease the reference count added from QQmlTypeLoader::getType()
         // When a singleton tries to reference itself, it may not be complete yet.
         if (tdata->isComplete()) {
-            initMetaObjectResolver(resolver, qmlEngine->propertyCacheForType(tdata->compiledData()->metaTypeId));
-            resolver->flags |= AllPropertiesAreFinal;
-            return resolver->resolveMember(qmlEngine, resolver, member);
+            auto newResolver = resolver->owner->New<QV4::IR::MemberExpressionResolver>();
+            newResolver->owner = resolver->owner;
+            initMetaObjectResolver(newResolver, qmlEngine->propertyCacheForType(tdata->compiledData()->metaTypeId));
+            newResolver->flags |= AllPropertiesAreFinal;
+            return newResolver->resolveMember(qmlEngine, newResolver, member);
         }
     }  else if (type->isSingleton()) {
         const QMetaObject *singletonMeta = type->singletonInstanceInfo()->instanceMetaObject;
         if (singletonMeta) { // QJSValue-based singletons cannot be accelerated
-            initMetaObjectResolver(resolver, qmlEngine->cache(singletonMeta));
+            auto newResolver = resolver->owner->New<QV4::IR::MemberExpressionResolver>();
+            newResolver->owner = resolver->owner;
+            initMetaObjectResolver(newResolver, qmlEngine->cache(singletonMeta));
             member->kind = QV4::IR::Member::MemberOfSingletonObject;
-            return resolver->resolveMember(qmlEngine, resolver, member);
+            return newResolver->resolveMember(qmlEngine, newResolver, member);
         }
     } else if (const QMetaObject *attachedMeta = type->attachedPropertiesType(qmlEngine)) {
         QQmlPropertyCache *cache = qmlEngine->cache(attachedMeta);
-        initMetaObjectResolver(resolver, cache);
+        auto newResolver = resolver->owner->New<QV4::IR::MemberExpressionResolver>();
+        newResolver->owner = resolver->owner;
+        initMetaObjectResolver(newResolver, cache);
         member->setAttachedPropertiesId(type->attachedPropertiesId(qmlEngine));
-        return resolver->resolveMember(qmlEngine, resolver, member);
+        return newResolver->resolveMember(qmlEngine, newResolver, member);
     }
 
-    resolver->clear();
     return result;
 }
 
@@ -1643,7 +1649,9 @@ static void initQmlTypeResolver(QV4::IR::MemberExpressionResolver *resolver, QQm
     resolver->flags = 0;
 }
 
-static QV4::IR::Type resolveImportNamespace(QQmlEnginePrivate *, QV4::IR::MemberExpressionResolver *resolver, QV4::IR::Member *member)
+static QV4::IR::DiscoveredType resolveImportNamespace(
+        QQmlEnginePrivate *, const QV4::IR::MemberExpressionResolver *resolver,
+        QV4::IR::Member *member)
 {
     QV4::IR::Type result = QV4::IR::VarType;
     QQmlTypeNameCache *typeNamespace = static_cast<QQmlTypeNameCache*>(resolver->extraData);
@@ -1660,19 +1668,21 @@ static QV4::IR::Type resolveImportNamespace(QQmlEnginePrivate *, QV4::IR::Member
             // through the singleton getter in the run-time. Until then we
             // can't accelerate access :(
             if (!r.type->isSingleton()) {
-                initQmlTypeResolver(resolver, r.type);
-                return QV4::IR::QObjectType;
+                auto newResolver = resolver->owner->New<QV4::IR::MemberExpressionResolver>();
+                newResolver->owner = resolver->owner;
+                initQmlTypeResolver(newResolver, r.type);
+                return QV4::IR::DiscoveredType(newResolver);
             }
         } else {
             Q_ASSERT(false); // How can this happen?
         }
     }
 
-    resolver->clear();
     return result;
 }
 
-static void initImportNamespaceResolver(QV4::IR::MemberExpressionResolver *resolver, QQmlTypeNameCache *imports, const void *importNamespace)
+static void initImportNamespaceResolver(QV4::IR::MemberExpressionResolver *resolver,
+                                        QQmlTypeNameCache *imports, const void *importNamespace)
 {
     resolver->resolveMember = &resolveImportNamespace;
     resolver->data = const_cast<void*>(importNamespace);
@@ -1680,7 +1690,9 @@ static void initImportNamespaceResolver(QV4::IR::MemberExpressionResolver *resol
     resolver->flags = 0;
 }
 
-static QV4::IR::Type resolveMetaObjectProperty(QQmlEnginePrivate *qmlEngine, QV4::IR::MemberExpressionResolver *resolver, QV4::IR::Member *member)
+static QV4::IR::DiscoveredType resolveMetaObjectProperty(
+        QQmlEnginePrivate *qmlEngine, const QV4::IR::MemberExpressionResolver *resolver,
+        QV4::IR::Member *member)
 {
     QV4::IR::Type result = QV4::IR::VarType;
     QQmlPropertyCache *metaObject = static_cast<QQmlPropertyCache*>(resolver->data);
@@ -1694,7 +1706,6 @@ static QV4::IR::Type resolveMetaObjectProperty(QQmlEnginePrivate *qmlEngine, QV4
             int value = metaEnum.keyToValue(enumName.constData(), &ok);
             if (ok) {
                 member->setEnumValue(value);
-                resolver->clear();
                 return QV4::IR::SInt32Type;
             }
         }
@@ -1739,21 +1750,25 @@ static QV4::IR::Type resolveMetaObjectProperty(QQmlEnginePrivate *qmlEngine, QV4
             default:
                 if (property->isQObject()) {
                     if (QQmlPropertyCache *cache = qmlEngine->propertyCacheForType(property->propType)) {
-                        initMetaObjectResolver(resolver, cache);
-                        return QV4::IR::QObjectType;
+                        auto newResolver = resolver->owner->New<QV4::IR::MemberExpressionResolver>();
+                        newResolver->owner = resolver->owner;
+                        initMetaObjectResolver(newResolver, cache);
+                        return QV4::IR::DiscoveredType(newResolver);
                     }
                 } else if (const QMetaObject *valueTypeMetaObject = QQmlValueTypeFactory::metaObjectForMetaType(property->propType)) {
                     if (QQmlPropertyCache *cache = qmlEngine->cache(valueTypeMetaObject)) {
-                        initMetaObjectResolver(resolver, cache);
-                        resolver->flags |= ResolveTypeInformationOnly;
-                        return QV4::IR::QObjectType;
+                        auto newResolver = resolver->owner->New<QV4::IR::MemberExpressionResolver>();
+                        newResolver->owner = resolver->owner;
+                        initMetaObjectResolver(newResolver, cache);
+                        newResolver->flags |= ResolveTypeInformationOnly;
+                        return QV4::IR::DiscoveredType(newResolver);
                     }
                 }
                 break;
             }
         }
     }
-    resolver->clear();
+
     return result;
 }
 
@@ -1809,6 +1824,7 @@ QV4::IR::Expr *JSCodeGen::fallbackNameLookup(const QString &name, int line, int
             result = _block->TEMP(result->index);
             if (mapping.type) {
                 result->memberResolver = _function->New<QV4::IR::MemberExpressionResolver>();
+                result->memberResolver->owner = _function;
                 initMetaObjectResolver(result->memberResolver, mapping.type);
                 result->memberResolver->flags |= AllPropertiesAreFinal;
             }
@@ -1831,6 +1847,7 @@ QV4::IR::Expr *JSCodeGen::fallbackNameLookup(const QString &name, int line, int
 
                 result = _block->TEMP(result->index);
                 result->memberResolver = _function->New<QV4::IR::MemberExpressionResolver>();
+                result->memberResolver->owner = _function;
                 initQmlTypeResolver(result->memberResolver, r.type);
                 return result;
             } else {
@@ -1839,6 +1856,7 @@ QV4::IR::Expr *JSCodeGen::fallbackNameLookup(const QString &name, int line, int
                 namespaceName->freeOfSideEffects = true;
                 QV4::IR::Temp *result = _block->TEMP(_block->newTemp());
                 result->memberResolver = _function->New<QV4::IR::MemberExpressionResolver>();
+                result->memberResolver->owner = _function;
                 initImportNamespaceResolver(result->memberResolver, imports, r.importNamespace);
 
                 _block->MOVE(result, namespaceName);
@@ -1855,6 +1873,7 @@ QV4::IR::Expr *JSCodeGen::fallbackNameLookup(const QString &name, int line, int
         if (pd) {
             QV4::IR::Temp *base = _block->TEMP(_qmlContextTemp);
             base->memberResolver = _function->New<QV4::IR::MemberExpressionResolver>();
+            base->memberResolver->owner = _function;
             initMetaObjectResolver(base->memberResolver, _scopeObject);
             return _block->MEMBER(base, _function->newString(name), pd, QV4::IR::Member::MemberOfQmlScopeObject);
         }
@@ -1868,6 +1887,7 @@ QV4::IR::Expr *JSCodeGen::fallbackNameLookup(const QString &name, int line, int
         if (pd) {
             QV4::IR::Temp *base = _block->TEMP(_qmlContextTemp);
             base->memberResolver = _function->New<QV4::IR::MemberExpressionResolver>();
+            base->memberResolver->owner = _function;
             initMetaObjectResolver(base->memberResolver, _contextObject);
             return _block->MEMBER(base, _function->newString(name), pd, QV4::IR::Member::MemberOfQmlContextObject);
         }
diff --git a/src/qml/compiler/qqmltypecompiler.cpp b/src/qml/compiler/qqmltypecompiler.cpp
index 33716d57b8..a71793f2b6 100644
--- a/src/qml/compiler/qqmltypecompiler.cpp
+++ b/src/qml/compiler/qqmltypecompiler.cpp
@@ -2731,8 +2731,8 @@ bool QQmlJavaScriptBindingExpressionSimplificationPass::simplifyBinding(QV4::IR:
     if (function->basicBlockCount() > 10)
         return false;
 
-    foreach (QV4::IR::BasicBlock *bb, function->basicBlocks()) {
-        foreach (QV4::IR::Stmt *s, bb->statements()) {
+    for (QV4::IR::BasicBlock *bb : function->basicBlocks()) {
+        for (QV4::IR::Stmt *s : bb->statements()) {
             s->accept(this);
             if (!_canSimplify)
                 return false;
@@ -2901,8 +2901,8 @@ void QQmlIRFunctionCleanser::clean()
     module->functions = newFunctions;
 
     foreach (QV4::IR::Function *function, module->functions) {
-        foreach (QV4::IR::BasicBlock *block, function->basicBlocks()) {
-            foreach (QV4::IR::Stmt *s, block->statements()) {
+        for (QV4::IR::BasicBlock *block : function->basicBlocks()) {
+            for (QV4::IR::Stmt *s : block->statements()) {
                 s->accept(this);
             }
         }
diff --git a/src/qml/compiler/qv4isel_moth.cpp b/src/qml/compiler/qv4isel_moth.cpp
index b3468848ca..be10d50e9b 100644
--- a/src/qml/compiler/qv4isel_moth.cpp
+++ b/src/qml/compiler/qv4isel_moth.cpp
@@ -255,16 +255,16 @@ protected:
 
         if (IR::Jump *jump = s->asJump()) {
             IR::MoveMapping moves;
-            foreach (IR::Stmt *succStmt, jump->target->statements()) {
+            for (IR::Stmt *succStmt : jump->target->statements()) {
                 if (IR::Phi *phi = succStmt->asPhi()) {
                     forceActivation(*phi->targetTemp);
-                    for (int i = 0, ei = phi->d->incoming.size(); i != ei; ++i) {
-                        IR::Expr *e = phi->d->incoming[i];
+                    for (int i = 0, ei = phi->incoming.size(); i != ei; ++i) {
+                        IR::Expr *e = phi->incoming[i];
                         if (IR::Temp *t = e->asTemp()) {
                             forceActivation(*t);
                         }
                         if (jump->target->in[i] == _currentBasicBlock)
-                            moves.add(phi->d->incoming[i], phi->targetTemp);
+                            moves.add(phi->incoming[i], phi->targetTemp);
                     }
                 } else {
                     break;
@@ -303,7 +303,7 @@ protected:
 #if !defined(QT_NO_DEBUG)
         Q_ASSERT(_stackSlotForTemp.contains(phi->targetTemp->index));
         Q_ASSERT(_slotIsInUse[_stackSlotForTemp[phi->targetTemp->index]]);
-        foreach (IR::Expr *e, phi->d->incoming) {
+        foreach (IR::Expr *e, phi->incoming) {
             if (IR::Temp *t = e->asTemp())
                 Q_ASSERT(_stackSlotForTemp.contains(t->index));
         }
@@ -385,7 +385,7 @@ void InstructionSelection::run(int functionIndex)
     addInstruction(push);
 
     currentLine = 0;
-    QVector<IR::BasicBlock *> basicBlocks = _function->basicBlocks();
+    const QVector<IR::BasicBlock *> &basicBlocks = _function->basicBlocks();
     for (int i = 0, ei = basicBlocks.size(); i != ei; ++i) {
         blockNeedsDebugInstruction = irModule->debugMode;
         _block = basicBlocks[i];
@@ -404,7 +404,7 @@ void InstructionSelection::run(int functionIndex)
             exceptionHandler = _block->catchBlock;
         }
 
-        foreach (IR::Stmt *s, _block->statements()) {
+        for (IR::Stmt *s : _block->statements()) {
             _currentStatement = s;
 
             if (s->location.isValid()) {
diff --git a/src/qml/compiler/qv4isel_util_p.h b/src/qml/compiler/qv4isel_util_p.h
index 9ef3ef6721..674fc01623 100644
--- a/src/qml/compiler/qv4isel_util_p.h
+++ b/src/qml/compiler/qv4isel_util_p.h
@@ -145,11 +145,11 @@ public:
     {
         _stackSlotForTemp.reserve(function->tempCount);
 
-        foreach (IR::BasicBlock *bb, function->basicBlocks()) {
+        for (IR::BasicBlock *bb : function->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
             _currentBasicBlock = bb;
-            foreach (IR::Stmt *s, bb->statements())
+            for (IR::Stmt *s : bb->statements())
                 process(s);
         }
 
diff --git a/src/qml/compiler/qv4jsir.cpp b/src/qml/compiler/qv4jsir.cpp
index 4c87b7557e..b28db59190 100644
--- a/src/qml/compiler/qv4jsir.cpp
+++ b/src/qml/compiler/qv4jsir.cpp
@@ -511,344 +511,23 @@ void Function::setStatementCount(int cnt)
     _statementCount = cnt;
 }
 
-BasicBlock::~BasicBlock()
-{
-    for (Stmt *s : qAsConst(_statements)) {
-        Phi *p = s->asPhi();
-        if (p)
-            p->destroyData();
-    }
-}
-
-unsigned BasicBlock::newTemp()
-{
-    Q_ASSERT(!isRemoved());
-    return function->tempCount++;
-}
-
-Temp *BasicBlock::TEMP(unsigned index)
-{
-    Q_ASSERT(!isRemoved());
-    Temp *e = function->New<Temp>();
-    e->init(Temp::VirtualRegister, index);
-    return e;
-}
-
-ArgLocal *BasicBlock::ARG(unsigned index, unsigned scope)
-{
-    Q_ASSERT(!isRemoved());
-    ArgLocal *e = function->New<ArgLocal>();
-    e->init(scope ? ArgLocal::ScopedFormal : ArgLocal::Formal, index, scope);
-    return e;
-}
-
-ArgLocal *BasicBlock::LOCAL(unsigned index, unsigned scope)
-{
-    Q_ASSERT(!isRemoved());
-    ArgLocal *e = function->New<ArgLocal>();
-    e->init(scope ? ArgLocal::ScopedLocal : ArgLocal::Local, index, scope);
-    return e;
-}
-
-Expr *BasicBlock::CONST(Type type, double value)
-{
-    Q_ASSERT(!isRemoved());
-    Const *e = function->New<Const>();
-    if (type == NumberType) {
-        int ival = (int)value;
-        // +0 != -0, so we need to convert to double when negating 0
-        if (ival == value && !(value == 0 && isNegative(value)))
-            type = SInt32Type;
-        else
-            type = DoubleType;
-    } else if (type == NullType) {
-        value = 0;
-    } else if (type == UndefinedType) {
-        value = qQNaN();
-    }
-
-    e->init(type, value);
-    return e;
-}
-
-Expr *BasicBlock::STRING(const QString *value)
-{
-    Q_ASSERT(!isRemoved());
-    String *e = function->New<String>();
-    e->init(value);
-    return e;
-}
-
-Expr *BasicBlock::REGEXP(const QString *value, int flags)
-{
-    Q_ASSERT(!isRemoved());
-    RegExp *e = function->New<RegExp>();
-    e->init(value, flags);
-    return e;
-}
-
-Name *BasicBlock::NAME(const QString &id, quint32 line, quint32 column)
-{
-    Q_ASSERT(!isRemoved());
-    Name *e = function->New<Name>();
-    e->init(function->newString(id), line, column);
-    return e;
-}
-
-Name *BasicBlock::GLOBALNAME(const QString &id, quint32 line, quint32 column)
-{
-    Q_ASSERT(!isRemoved());
-    Name *e = function->New<Name>();
-    e->initGlobal(function->newString(id), line, column);
-    return e;
-}
-
-
-Name *BasicBlock::NAME(Name::Builtin builtin, quint32 line, quint32 column)
-{
-    Q_ASSERT(!isRemoved());
-    Name *e = function->New<Name>();
-    e->init(builtin, line, column);
-    return e;
-}
-
-Closure *BasicBlock::CLOSURE(int functionInModule)
-{
-    Q_ASSERT(!isRemoved());
-    Closure *clos = function->New<Closure>();
-    clos->init(functionInModule, function->module->functions.at(functionInModule)->name);
-    return clos;
-}
-
-Expr *BasicBlock::CONVERT(Expr *expr, Type type)
-{
-    Q_ASSERT(!isRemoved());
-    Convert *e = function->New<Convert>();
-    e->init(expr, type);
-    return e;
-}
-
-Expr *BasicBlock::UNOP(AluOp op, Expr *expr)
-{
-    Q_ASSERT(!isRemoved());
-    Unop *e = function->New<Unop>();
-    e->init(op, expr);
-    return e;
-}
-
-Expr *BasicBlock::BINOP(AluOp op, Expr *left, Expr *right)
-{
-    Q_ASSERT(!isRemoved());
-    Binop *e = function->New<Binop>();
-    e->init(op, left, right);
-    return e;
-}
-
-Expr *BasicBlock::CALL(Expr *base, ExprList *args)
-{
-    Q_ASSERT(!isRemoved());
-    Call *e = function->New<Call>();
-    e->init(base, args);
-    int argc = 0;
-    for (ExprList *it = args; it; it = it->next)
-        ++argc;
-    function->maxNumberOfArguments = qMax(function->maxNumberOfArguments, argc);
-    return e;
-}
-
-Expr *BasicBlock::NEW(Expr *base, ExprList *args)
-{
-    Q_ASSERT(!isRemoved());
-    New *e = function->New<New>();
-    e->init(base, args);
-    return e;
-}
-
-Expr *BasicBlock::SUBSCRIPT(Expr *base, Expr *index)
-{
-    Q_ASSERT(!isRemoved());
-    Subscript *e = function->New<Subscript>();
-    e->init(base, index);
-    return e;
-}
-
-Expr *BasicBlock::MEMBER(Expr *base, const QString *name, QQmlPropertyData *property, uchar kind, int attachedPropertiesIdOrEnumValue)
-{
-    Q_ASSERT(!isRemoved());
-    Member*e = function->New<Member>();
-    e->init(base, name, property, kind, attachedPropertiesIdOrEnumValue);
-    return e;
-}
-
-Stmt *BasicBlock::EXP(Expr *expr)
-{
-    Q_ASSERT(!isRemoved());
-    if (isTerminated())
-        return 0;
-
-    Exp *s = function->NewStmt<Exp>();
-    s->init(expr);
-    appendStatement(s);
-    return s;
-}
-
-Stmt *BasicBlock::MOVE(Expr *target, Expr *source)
-{
-    Q_ASSERT(!isRemoved());
-    if (isTerminated())
-        return 0;
-
-    Move *s = function->NewStmt<Move>();
-    s->init(target, source);
-    appendStatement(s);
-    return s;
-}
-
-Stmt *BasicBlock::JUMP(BasicBlock *target)
-{
-    Q_ASSERT(!isRemoved());
-    if (isTerminated())
-        return 0;
-
-    Jump *s = function->NewStmt<Jump>();
-    s->init(target);
-    appendStatement(s);
-
-    Q_ASSERT(! out.contains(target));
-    out.append(target);
-
-    Q_ASSERT(! target->in.contains(this));
-    target->in.append(this);
-
-    return s;
-}
-
-Stmt *BasicBlock::CJUMP(Expr *cond, BasicBlock *iftrue, BasicBlock *iffalse)
-{
-    Q_ASSERT(!isRemoved());
-    if (isTerminated())
-        return 0;
-
-    if (iftrue == iffalse) {
-        MOVE(TEMP(newTemp()), cond);
-        return JUMP(iftrue);
-    }
-
-    CJump *s = function->NewStmt<CJump>();
-    s->init(cond, iftrue, iffalse, this);
-    appendStatement(s);
-
-    Q_ASSERT(! out.contains(iftrue));
-    out.append(iftrue);
-
-    Q_ASSERT(! iftrue->in.contains(this));
-    iftrue->in.append(this);
-
-    Q_ASSERT(! out.contains(iffalse));
-    out.append(iffalse);
-
-    Q_ASSERT(! iffalse->in.contains(this));
-    iffalse->in.append(this);
-
-    return s;
-}
-
-Stmt *BasicBlock::RET(Expr *expr)
-{
-    Q_ASSERT(!isRemoved());
-    if (isTerminated())
-        return 0;
-
-    Ret *s = function->NewStmt<Ret>();
-    s->init(expr);
-    appendStatement(s);
-    return s;
-}
-
 void BasicBlock::setStatements(const QVector<Stmt *> &newStatements)
 {
     Q_ASSERT(!isRemoved());
     Q_ASSERT(newStatements.size() >= _statements.size());
-    // FIXME: this gets quite inefficient for large basic-blocks, so this function/case should be re-worked.
     for (Stmt *s : qAsConst(_statements)) {
-        Phi *p = s->asPhi();
-        if (!p)
-            continue;
-
-        if (!newStatements.contains(p))
-            p->destroyData();
+        if (Phi *p = s->asPhi()) {
+            if (!newStatements.contains(p)) {
+                // phi-node was not copied over, so:
+                p->destroyData();
+            }
+        } else {
+            break;
+        }
     }
     _statements = newStatements;
 }
 
-void BasicBlock::appendStatement(Stmt *statement)
-{
-    Q_ASSERT(!isRemoved());
-    if (nextLocation.startLine)
-        statement->location = nextLocation;
-    _statements.append(statement);
-}
-
-void BasicBlock::prependStatement(Stmt *stmt)
-{
-    Q_ASSERT(!isRemoved());
-    _statements.prepend(stmt);
-}
-
-void BasicBlock::prependStatements(const QVector<Stmt *> &stmts)
-{
-    Q_ASSERT(!isRemoved());
-    QVector<Stmt *> newStmts = stmts;
-    newStmts += _statements;
-    _statements = newStmts;
-}
-
-void BasicBlock::insertStatementBefore(Stmt *before, Stmt *newStmt)
-{
-    int idx = _statements.indexOf(before);
-    Q_ASSERT(idx >= 0);
-    _statements.insert(idx, newStmt);
-}
-
-void BasicBlock::insertStatementBefore(int index, Stmt *newStmt)
-{
-    Q_ASSERT(index >= 0);
-    _statements.insert(index, newStmt);
-}
-
-void BasicBlock::insertStatementBeforeTerminator(Stmt *stmt)
-{
-    Q_ASSERT(!isRemoved());
-    _statements.insert(_statements.size() - 1, stmt);
-}
-
-void BasicBlock::replaceStatement(int index, Stmt *newStmt)
-{
-    Q_ASSERT(!isRemoved());
-    Phi *p = _statements[index]->asPhi();
-    if (p)
-        p->destroyData();
-    _statements[index] = newStmt;
-}
-
-void BasicBlock::removeStatement(Stmt *stmt)
-{
-    Q_ASSERT(!isRemoved());
-    Phi *p = stmt->asPhi();
-    if (p)
-        p->destroyData();
-    _statements.remove(_statements.indexOf(stmt));
-}
-
-void BasicBlock::removeStatement(int idx)
-{
-    Q_ASSERT(!isRemoved());
-    Phi *p = _statements[idx]->asPhi();
-    if (p)
-        p->destroyData();
-    _statements.remove(idx);
-}
-
 CloneExpr::CloneExpr(BasicBlock *block)
     : block(block), cloned(0)
 {
@@ -1084,13 +763,13 @@ void IRPrinter::visitPhi(Phi *s)
 
     s->targetTemp->accept(this);
     *out << " = phi ";
-    for (int i = 0, ei = s->d->incoming.size(); i < ei; ++i) {
+    for (int i = 0, ei = s->incoming.size(); i < ei; ++i) {
         if (i > 0)
             *out << ", ";
         if (currentBB)
             *out << 'L' << currentBB->in.at(i)->index() << ": ";
-        if (s->d->incoming[i])
-            s->d->incoming[i]->accept(this);
+        if (s->incoming[i])
+            s->incoming[i]->accept(this);
     }
 }
 
diff --git a/src/qml/compiler/qv4jsir_p.h b/src/qml/compiler/qv4jsir_p.h
index 974e8dfe0d..eafecae494 100644
--- a/src/qml/compiler/qv4jsir_p.h
+++ b/src/qml/compiler/qv4jsir_p.h
@@ -244,13 +244,37 @@ struct StmtVisitor {
     virtual void visitPhi(Phi *) = 0;
 };
 
+struct MemberExpressionResolver;
+
+struct DiscoveredType {
+    int type;
+    MemberExpressionResolver *memberResolver;
+
+    DiscoveredType() : type(UnknownType), memberResolver(0) {}
+    DiscoveredType(Type t) : type(t), memberResolver(0) { Q_ASSERT(type != QObjectType); }
+    explicit DiscoveredType(int t) : type(t), memberResolver(0) { Q_ASSERT(type != QObjectType); }
+    explicit DiscoveredType(MemberExpressionResolver *memberResolver)
+        : type(QObjectType)
+        , memberResolver(memberResolver)
+    { Q_ASSERT(memberResolver); }
+
+    bool test(Type t) const { return type & t; }
+    bool isNumber() const { return (type & NumberType) && !(type & ~NumberType); }
+
+    bool operator!=(Type other) const { return type != other; }
+    bool operator==(Type other) const { return type == other; }
+    bool operator==(const DiscoveredType &other) const { return type == other.type; }
+    bool operator!=(const DiscoveredType &other) const { return type != other.type; }
+};
 
 struct MemberExpressionResolver
 {
-    typedef Type (*ResolveFunction)(QQmlEnginePrivate *engine, MemberExpressionResolver *resolver, Member *member);
+    typedef DiscoveredType (*ResolveFunction)(QQmlEnginePrivate *engine,
+                                              const MemberExpressionResolver *resolver,
+                                              Member *member);
 
     MemberExpressionResolver()
-        : resolveMember(0), data(0), extraData(0), flags(0) {}
+        : resolveMember(0), data(0), extraData(0), owner(nullptr), flags(0) {}
 
     bool isValid() const { return !!resolveMember; }
     void clear() { *this = MemberExpressionResolver(); }
@@ -258,6 +282,7 @@ struct MemberExpressionResolver
     ResolveFunction resolveMember;
     void *data; // Could be pointer to meta object, importNameSpace, etc. - depends on resolveMember implementation
     void *extraData; // Could be QQmlTypeNameCache
+    Function *owner;
     unsigned int flags;
 };
 
@@ -751,23 +776,21 @@ struct Ret: Stmt {
     virtual Ret *asRet() { return this; }
 };
 
+// Phi nodes can only occur at the start of a basic block. If there are any, they need to be
+// subsequent to eachother, and the first phi node should be the first statement in the basic-block.
+// A number of loops rely on this behavior, so they don't need to walk through the whole list
+// of instructions in a basic-block (e.g. the calls to destroyData in BasicBlock::~BasicBlock).
 struct Phi: Stmt {
     Temp *targetTemp;
-    struct Data {
-        QVector<Expr *> incoming; // used by Phi nodes
-    };
+    VarLengthArray<Expr *, 4> incoming;
 
-    Data *d;
-
-    Phi(int id): Stmt(id), d(0) {}
+    Phi(int id): Stmt(id) {}
 
     virtual void accept(StmtVisitor *v) { v->visitPhi(this); }
     virtual Phi *asPhi() { return this; }
 
-    void destroyData() {
-        delete d;
-        d = 0;
-    }
+    void destroyData()
+    { incoming.~VarLengthArray(); }
 };
 
 struct Q_QML_PRIVATE_EXPORT Module {
@@ -813,7 +836,17 @@ public:
         , _groupStart(false)
         , _isRemoved(false)
     {}
-    ~BasicBlock();
+
+    ~BasicBlock()
+    {
+        for (Stmt *s : qAsConst(_statements)) {
+            if (Phi *p = s->asPhi()) {
+                p->destroyData();
+            } else {
+                break;
+            }
+        }
+    }
 
     const QVector<Stmt *> &statements() const
     {
@@ -836,15 +869,73 @@ public:
         return i;
     }
 
-    void appendStatement(Stmt *statement);
-    void prependStatement(Stmt *stmt);
-    void prependStatements(const QVector<Stmt *> &stmts);
-    void insertStatementBefore(Stmt *before, Stmt *newStmt);
-    void insertStatementBefore(int index, Stmt *newStmt);
-    void insertStatementBeforeTerminator(Stmt *stmt);
-    void replaceStatement(int index, Stmt *newStmt);
-    void removeStatement(Stmt *stmt);
-    void removeStatement(int idx);
+    void appendStatement(Stmt *statement)
+    {
+        Q_ASSERT(!isRemoved());
+        if (nextLocation.startLine)
+            statement->location = nextLocation;
+        _statements.append(statement);
+    }
+
+    void prependStatement(Stmt *stmt)
+    {
+        Q_ASSERT(!isRemoved());
+        _statements.prepend(stmt);
+    }
+
+    void prependStatements(const QVector<Stmt *> &stmts)
+    {
+        Q_ASSERT(!isRemoved());
+        QVector<Stmt *> newStmts = stmts;
+        newStmts += _statements;
+        _statements = newStmts;
+    }
+
+    void insertStatementBefore(Stmt *before, Stmt *newStmt)
+    {
+        int idx = _statements.indexOf(before);
+        Q_ASSERT(idx >= 0);
+        _statements.insert(idx, newStmt);
+    }
+
+    void insertStatementBefore(int index, Stmt *newStmt)
+    {
+        Q_ASSERT(index >= 0);
+        _statements.insert(index, newStmt);
+    }
+
+    void insertStatementBeforeTerminator(Stmt *stmt)
+    {
+        Q_ASSERT(!isRemoved());
+        _statements.insert(_statements.size() - 1, stmt);
+    }
+
+    void replaceStatement(int index, Stmt *newStmt)
+    {
+        Q_ASSERT(!isRemoved());
+        if (Phi *p = _statements[index]->asPhi()) {
+            p->destroyData();
+        }
+        _statements[index] = newStmt;
+    }
+
+    void removeStatement(Stmt *stmt)
+    {
+        Q_ASSERT(!isRemoved());
+        if (Phi *p = stmt->asPhi()) {
+            p->destroyData();
+        }
+        _statements.remove(_statements.indexOf(stmt));
+    }
+
+    void removeStatement(int idx)
+    {
+        Q_ASSERT(!isRemoved());
+        if (Phi *p = _statements[idx]->asPhi()) {
+            p->destroyData();
+        }
+        _statements.remove(idx);
+    }
 
     inline bool isEmpty() const {
         Q_ASSERT(!isRemoved());
@@ -1209,6 +1300,251 @@ protected:
     BasicBlock *currentBB;
 };
 
+inline unsigned BasicBlock::newTemp()
+{
+    Q_ASSERT(!isRemoved());
+    return function->tempCount++;
+}
+
+inline Temp *BasicBlock::TEMP(unsigned index)
+{
+    Q_ASSERT(!isRemoved());
+    Temp *e = function->New<Temp>();
+    e->init(Temp::VirtualRegister, index);
+    return e;
+}
+
+inline ArgLocal *BasicBlock::ARG(unsigned index, unsigned scope)
+{
+    Q_ASSERT(!isRemoved());
+    ArgLocal *e = function->New<ArgLocal>();
+    e->init(scope ? ArgLocal::ScopedFormal : ArgLocal::Formal, index, scope);
+    return e;
+}
+
+inline ArgLocal *BasicBlock::LOCAL(unsigned index, unsigned scope)
+{
+    Q_ASSERT(!isRemoved());
+    ArgLocal *e = function->New<ArgLocal>();
+    e->init(scope ? ArgLocal::ScopedLocal : ArgLocal::Local, index, scope);
+    return e;
+}
+
+inline Expr *BasicBlock::CONST(Type type, double value)
+{
+    Q_ASSERT(!isRemoved());
+    Const *e = function->New<Const>();
+    if (type == NumberType) {
+        int ival = (int)value;
+        // +0 != -0, so we need to convert to double when negating 0
+        if (ival == value && !(value == 0 && isNegative(value)))
+            type = SInt32Type;
+        else
+            type = DoubleType;
+    } else if (type == NullType) {
+        value = 0;
+    } else if (type == UndefinedType) {
+        value = qQNaN();
+    }
+
+    e->init(type, value);
+    return e;
+}
+
+inline Expr *BasicBlock::STRING(const QString *value)
+{
+    Q_ASSERT(!isRemoved());
+    String *e = function->New<String>();
+    e->init(value);
+    return e;
+}
+
+inline Expr *BasicBlock::REGEXP(const QString *value, int flags)
+{
+    Q_ASSERT(!isRemoved());
+    RegExp *e = function->New<RegExp>();
+    e->init(value, flags);
+    return e;
+}
+
+inline Name *BasicBlock::NAME(const QString &id, quint32 line, quint32 column)
+{
+    Q_ASSERT(!isRemoved());
+    Name *e = function->New<Name>();
+    e->init(function->newString(id), line, column);
+    return e;
+}
+
+inline Name *BasicBlock::GLOBALNAME(const QString &id, quint32 line, quint32 column)
+{
+    Q_ASSERT(!isRemoved());
+    Name *e = function->New<Name>();
+    e->initGlobal(function->newString(id), line, column);
+    return e;
+}
+
+
+inline Name *BasicBlock::NAME(Name::Builtin builtin, quint32 line, quint32 column)
+{
+    Q_ASSERT(!isRemoved());
+    Name *e = function->New<Name>();
+    e->init(builtin, line, column);
+    return e;
+}
+
+inline Closure *BasicBlock::CLOSURE(int functionInModule)
+{
+    Q_ASSERT(!isRemoved());
+    Closure *clos = function->New<Closure>();
+    clos->init(functionInModule, function->module->functions.at(functionInModule)->name);
+    return clos;
+}
+
+inline Expr *BasicBlock::CONVERT(Expr *expr, Type type)
+{
+    Q_ASSERT(!isRemoved());
+    Convert *e = function->New<Convert>();
+    e->init(expr, type);
+    return e;
+}
+
+inline Expr *BasicBlock::UNOP(AluOp op, Expr *expr)
+{
+    Q_ASSERT(!isRemoved());
+    Unop *e = function->New<Unop>();
+    e->init(op, expr);
+    return e;
+}
+
+inline Expr *BasicBlock::BINOP(AluOp op, Expr *left, Expr *right)
+{
+    Q_ASSERT(!isRemoved());
+    Binop *e = function->New<Binop>();
+    e->init(op, left, right);
+    return e;
+}
+
+inline Expr *BasicBlock::CALL(Expr *base, ExprList *args)
+{
+    Q_ASSERT(!isRemoved());
+    Call *e = function->New<Call>();
+    e->init(base, args);
+    int argc = 0;
+    for (ExprList *it = args; it; it = it->next)
+        ++argc;
+    function->maxNumberOfArguments = qMax(function->maxNumberOfArguments, argc);
+    return e;
+}
+
+inline Expr *BasicBlock::NEW(Expr *base, ExprList *args)
+{
+    Q_ASSERT(!isRemoved());
+    New *e = function->New<New>();
+    e->init(base, args);
+    return e;
+}
+
+inline Expr *BasicBlock::SUBSCRIPT(Expr *base, Expr *index)
+{
+    Q_ASSERT(!isRemoved());
+    Subscript *e = function->New<Subscript>();
+    e->init(base, index);
+    return e;
+}
+
+inline Expr *BasicBlock::MEMBER(Expr *base, const QString *name, QQmlPropertyData *property, uchar kind, int attachedPropertiesIdOrEnumValue)
+{
+    Q_ASSERT(!isRemoved());
+    Member*e = function->New<Member>();
+    e->init(base, name, property, kind, attachedPropertiesIdOrEnumValue);
+    return e;
+}
+
+inline Stmt *BasicBlock::EXP(Expr *expr)
+{
+    Q_ASSERT(!isRemoved());
+    if (isTerminated())
+        return 0;
+
+    Exp *s = function->NewStmt<Exp>();
+    s->init(expr);
+    appendStatement(s);
+    return s;
+}
+
+inline Stmt *BasicBlock::MOVE(Expr *target, Expr *source)
+{
+    Q_ASSERT(!isRemoved());
+    if (isTerminated())
+        return 0;
+
+    Move *s = function->NewStmt<Move>();
+    s->init(target, source);
+    appendStatement(s);
+    return s;
+}
+
+inline Stmt *BasicBlock::JUMP(BasicBlock *target)
+{
+    Q_ASSERT(!isRemoved());
+    if (isTerminated())
+        return 0;
+
+    Jump *s = function->NewStmt<Jump>();
+    s->init(target);
+    appendStatement(s);
+
+    Q_ASSERT(! out.contains(target));
+    out.append(target);
+
+    Q_ASSERT(! target->in.contains(this));
+    target->in.append(this);
+
+    return s;
+}
+
+inline Stmt *BasicBlock::CJUMP(Expr *cond, BasicBlock *iftrue, BasicBlock *iffalse)
+{
+    Q_ASSERT(!isRemoved());
+    if (isTerminated())
+        return 0;
+
+    if (iftrue == iffalse) {
+        MOVE(TEMP(newTemp()), cond);
+        return JUMP(iftrue);
+    }
+
+    CJump *s = function->NewStmt<CJump>();
+    s->init(cond, iftrue, iffalse, this);
+    appendStatement(s);
+
+    Q_ASSERT(! out.contains(iftrue));
+    out.append(iftrue);
+
+    Q_ASSERT(! iftrue->in.contains(this));
+    iftrue->in.append(this);
+
+    Q_ASSERT(! out.contains(iffalse));
+    out.append(iffalse);
+
+    Q_ASSERT(! iffalse->in.contains(this));
+    iffalse->in.append(this);
+
+    return s;
+}
+
+inline Stmt *BasicBlock::RET(Expr *expr)
+{
+    Q_ASSERT(!isRemoved());
+    if (isTerminated())
+        return 0;
+
+    Ret *s = function->NewStmt<Ret>();
+    s->init(expr);
+    appendStatement(s);
+    return s;
+}
+
 } // end of namespace IR
 
 } // end of namespace QV4
diff --git a/src/qml/compiler/qv4ssa.cpp b/src/qml/compiler/qv4ssa.cpp
index 7881ab951a..6a4c1c54d6 100644
--- a/src/qml/compiler/qv4ssa.cpp
+++ b/src/qml/compiler/qv4ssa.cpp
@@ -56,7 +56,6 @@
 #include <cmath>
 #include <iostream>
 #include <cassert>
-#include <algorithm>
 
 QT_USE_NAMESPACE
 
@@ -87,120 +86,6 @@ static void showMeTheCode(IR::Function *function, const char *marker)
     }
 }
 
-#if !defined(BROKEN_STD_VECTOR_BOOL_OR_BROKEN_STD_FIND)
-// Sanity:
-class BitVector
-{
-    std::vector<bool> bits;
-
-public:
-    BitVector(int size = 0, bool value = false)
-        : bits(size, value)
-    {}
-
-    void reserve(int size)
-    { bits.reserve(size); }
-
-    int size() const
-    {
-        Q_ASSERT(bits.size() < INT_MAX);
-        return static_cast<int>(bits.size());
-    }
-
-    void resize(int newSize)
-    { bits.resize(newSize); }
-
-    void assign(int newSize, bool value)
-    { bits.assign(newSize, value); }
-
-    int findNext(int start, bool value, bool wrapAround) const
-    {
-        // The ++operator of std::vector<bool>::iterator in libc++ has a bug when using it on an
-        // iterator pointing to the last element. It will not be set to ::end(), but beyond
-        // that. (It will be set to the first multiple of the native word size that is bigger
-        // than size().)
-        //
-        // See http://llvm.org/bugs/show_bug.cgi?id=19663
-        //
-        // The work-around is to calculate the distance, and compare it to the size() to see if it's
-        // beyond the end, or take the minimum of the distance and the size.
-
-        size_t pos = std::distance(bits.begin(),
-                                   std::find(bits.begin() + start, bits.end(), value));
-        if (wrapAround && pos >= static_cast<size_t>(size()))
-            pos = std::distance(bits.begin(),
-                                std::find(bits.begin(), bits.begin() + start, value));
-
-        pos = qMin(pos, static_cast<size_t>(size()));
-
-        Q_ASSERT(pos <= static_cast<size_t>(size()));
-        Q_ASSERT(pos < INT_MAX);
-
-        return static_cast<int>(pos);
-    }
-
-    bool at(int idx) const
-    { return bits.at(idx); }
-
-    void setBit(int idx)
-    { bits[idx] = true; }
-
-    void clearBit(int idx)
-    { bits[idx] = false; }
-};
-#else // Insanity:
-class BitVector
-{
-    QBitArray bits;
-
-public:
-    BitVector(int size = 0, bool value = false)
-        : bits(size, value)
-    {}
-
-    void reserve(int size)
-    { Q_UNUSED(size); }
-
-    int size() const
-    { return bits.size(); }
-
-    void resize(int newSize)
-    { bits.resize(newSize); }
-
-    void assign(int newSize, bool value)
-    {
-        bits.resize(newSize);
-        bits.fill(value);
-    }
-
-    int findNext(int start, bool value, bool wrapAround) const
-    {
-        for (int i = start, ei = size(); i < ei; ++i) {
-            if (at(i) == value)
-                return i;
-        }
-
-        if (wrapAround) {
-            for (int i = 0, ei = start; i < ei; ++i) {
-                if (at(i) == value)
-                    return i;
-            }
-        }
-
-        return size();
-    }
-
-    bool at(int idx) const
-    { return bits.at(idx); }
-
-    void setBit(int idx)
-    { bits[idx] = true; }
-
-    void clearBit(int idx)
-    { bits[idx] = false; }
-};
-#endif
-
 class ProcessedBlocks
 {
     BitVector processed;
@@ -557,7 +442,7 @@ class DominatorTree
             BasicBlockIndex p = d->parent[n];
             BasicBlockIndex s = p;
 
-            foreach (BasicBlock *v, function->basicBlock(n)->in) {
+            for (BasicBlock *v : function->basicBlock(n)->in) {
                 BasicBlockIndex ss = InvalidBasicBlockIndex;
                 if (d->dfnum[v->index()] <= d->dfnum[n])
                     ss = v->index();
@@ -617,7 +502,7 @@ public:
         // compute children of each node in the dominator tree
         std::vector<std::vector<BasicBlockIndex> > children; // BasicBlock index -> children
         children.resize(function->basicBlockCount());
-        foreach (BasicBlock *n, function->basicBlocks()) {
+        for (BasicBlock *n : function->basicBlocks()) {
             if (n->isRemoved())
                 continue;
             const BasicBlockIndex nodeIndex = n->index();
@@ -633,7 +518,7 @@ public:
         nodeStatus.resize(function->basicBlockCount());
         std::vector<BasicBlockIndex> worklist;
         worklist.reserve(function->basicBlockCount());
-        foreach (BasicBlock *bb, function->basicBlocks()) {
+        for (BasicBlock *bb : function->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
             BasicBlockIndex nodeIndex = bb->index();
@@ -667,7 +552,7 @@ public:
             if (np.todo.empty()) {
                 BasicBlockSet &S = DF[node];
                 S.init(function);
-                foreach (BasicBlock *y, function->basicBlock(node)->out)
+                for (BasicBlock *y : function->basicBlock(node)->out)
                     if (idom[y->index()] != node)
                         S.insert(y);
                 for (BasicBlockIndex child : np.children) {
@@ -689,7 +574,7 @@ public:
             buf.open(QIODevice::WriteOnly);
             QTextStream qout(&buf);
             qout << "Dominator Frontiers:" << endl;
-            foreach (BasicBlock *n, function->basicBlocks()) {
+            for (BasicBlock *n : function->basicBlocks()) {
                 if (n->isRemoved())
                     continue;
 
@@ -706,7 +591,7 @@ public:
         }
 
         if (DebugDominatorFrontiers && DebugCodeCanUseLotsOfCpu) {
-            foreach (BasicBlock *n, function->basicBlocks()) {
+            for (BasicBlock *n : function->basicBlocks()) {
                 if (n->isRemoved())
                     continue;
                 const BasicBlockSet &fBlocks = DF[n->index()];
@@ -714,7 +599,7 @@ public:
                     BasicBlock *fBlock = *it;
                     Q_ASSERT(!dominates(n, fBlock) || fBlock == n);
                     bool hasDominatedSucc = false;
-                    foreach (BasicBlock *succ, fBlock->in) {
+                    for (BasicBlock *succ : fBlock->in) {
                         if (dominates(n, succ)) {
                             hasDominatedSucc = true;
                             break;
@@ -747,7 +632,7 @@ public:
             buf.open(QIODevice::WriteOnly);
             QTextStream qout(&buf);
             qout << "Immediate dominators:" << endl;
-            foreach (BasicBlock *to, function->basicBlocks()) {
+            for (BasicBlock *to : function->basicBlocks()) {
                 if (to->isRemoved())
                     continue;
 
@@ -881,7 +766,7 @@ private:
     {
         std::vector<int> nodeDepths(size_t(function->basicBlockCount()), -1);
         nodeDepths[0] = 0;
-        foreach (BasicBlock *bb, function->basicBlocks()) {
+        for (BasicBlock *bb : function->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
 
@@ -945,8 +830,7 @@ private:
         std::vector<BasicBlockIndex> prefix;
         prefix.reserve(32);
 
-        for (int i = 0, ei = node->in.size(); i != ei; ++i) {
-            BasicBlock *in = node->in.at(i);
+        for (BasicBlock *in : node->in) {
             if (node == in) // back-edge to self
                 continue;
             if (dominates(node->index(), in->index())) // a known back-edge
@@ -1055,13 +939,13 @@ public:
         for (size_t i = 0; i != ei; ++i)
             A_orig[i].reserve(8);
 
-        foreach (BasicBlock *bb, function->basicBlocks()) {
+        for (BasicBlock *bb : function->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
 
             currentBB = bb;
             killed.assign(function->tempCount, false);
-            foreach (Stmt *s, bb->statements())
+            for (Stmt *s : bb->statements())
                 s->accept(this);
         }
     }
@@ -1381,16 +1265,15 @@ public:
 
 void insertPhiNode(const Temp &a, BasicBlock *y, IR::Function *f) {
     Phi *phiNode = f->NewStmt<Phi>();
-    phiNode->d = new Phi::Data;
     phiNode->targetTemp = f->New<Temp>();
     phiNode->targetTemp->init(a.kind, a.index);
     y->prependStatement(phiNode);
 
-    phiNode->d->incoming.resize(y->in.size());
+    phiNode->incoming.resize(y->in.size());
     for (int i = 0, ei = y->in.size(); i < ei; ++i) {
         Temp *t = f->New<Temp>();
         t->init(a.kind, a.index);
-        phiNode->d->incoming[i] = t;
+        phiNode->incoming[i] = t;
     }
 }
 
@@ -1565,7 +1448,7 @@ private:
             processed.markAsProcessed(bb);
 
             BasicBlock *next = 0;
-            foreach (BasicBlock *out, bb->out) {
+            for (BasicBlock *out : bb->out) {
                 if (processed.alreadyProcessed(out))
                     continue;
                 if (!next)
@@ -1581,17 +1464,17 @@ private:
     {
         currentBB = bb;
 
-        foreach (Stmt *s, bb->statements()) {
+        for (Stmt *s : bb->statements()) {
             currentStmt = s;
             s->accept(this);
         }
 
-        foreach (BasicBlock *Y, bb->out) {
+        for (BasicBlock *Y : bb->out) {
             const int j = Y->in.indexOf(bb);
             Q_ASSERT(j >= 0 && j < Y->in.size());
-            foreach (Stmt *s, Y->statements()) {
+            for (Stmt *s : Y->statements()) {
                 if (Phi *phi = s->asPhi()) {
-                    Temp *t = phi->d->incoming[j]->asTemp();
+                    Temp *t = phi->incoming[j]->asTemp();
                     unsigned newTmp = currentNumber(*t);
 //                    qDebug()<<"I: replacing phi use"<<a<<"with"<<newTmp<<"in L"<<Y->index;
                     t->index = newTmp;
@@ -1845,11 +1728,11 @@ public:
     {
         grow();
 
-        foreach (BasicBlock *bb, function->basicBlocks()) {
+        for (BasicBlock *bb : function->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
 
-            foreach (Stmt *s, bb->statements()) {
+            for (Stmt *s : bb->statements()) {
                 if (!s)
                     continue;
 
@@ -1905,7 +1788,7 @@ public:
 
     void applyToFunction()
     {
-        foreach (BasicBlock *bb, theFunction->basicBlocks()) {
+        for (BasicBlock *bb : theFunction->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
 
@@ -1979,6 +1862,11 @@ public:
         return worklistSize == 0;
     }
 
+    unsigned size() const
+    {
+        return worklistSize;
+    }
+
     Stmt *takeNext(Stmt *last)
     {
         if (isEmpty())
@@ -2185,27 +2073,6 @@ protected:
     }
 };
 
-struct DiscoveredType {
-    int type;
-    MemberExpressionResolver *memberResolver;
-
-    DiscoveredType() : type(UnknownType), memberResolver(0) {}
-    DiscoveredType(Type t) : type(t), memberResolver(0) { Q_ASSERT(type != QObjectType); }
-    explicit DiscoveredType(int t) : type(t), memberResolver(0) { Q_ASSERT(type != QObjectType); }
-    explicit DiscoveredType(MemberExpressionResolver *memberResolver)
-        : type(QObjectType)
-        , memberResolver(memberResolver)
-    { Q_ASSERT(memberResolver); }
-
-    bool test(Type t) const { return type & t; }
-    bool isNumber() const { return (type & NumberType) && !(type & ~NumberType); }
-
-    bool operator!=(Type other) const { return type != other; }
-    bool operator==(Type other) const { return type == other; }
-    bool operator==(const DiscoveredType &other) const { return type == other.type; }
-    bool operator!=(const DiscoveredType &other) const { return type != other.type; }
-};
-
 class PropagateTempTypes: public StmtVisitor, ExprVisitor
 {
     const DefUses &defUses;
@@ -2274,7 +2141,7 @@ protected:
     virtual void visitRet(Ret *s) { s->expr->accept(this); }
     virtual void visitPhi(Phi *s) {
         s->targetTemp->accept(this);
-        foreach (Expr *e, s->d->incoming)
+        foreach (Expr *e, s->incoming)
             e->accept(this);
     }
 };
@@ -2306,6 +2173,7 @@ class TypeInference: public StmtVisitor, public ExprVisitor
         {}
     };
     TypingResult _ty;
+    Stmt *_currentStmt;
 
 public:
     TypeInference(QQmlEnginePrivate *qmlEngine, const DefUses &defUses)
@@ -2314,6 +2182,7 @@ public:
         , _tempTypes(_defUses.tempCount())
         , _worklist(0)
         , _ty(UnknownType)
+        , _currentStmt(nullptr)
     {}
 
     void run(StatementWorklist &w) {
@@ -2330,7 +2199,10 @@ public:
                 QTextStream qout(&buf);
                 qout<<"Typing stmt ";
                 IRPrinter(&qout).print(s);
+                qout.flush();
                 qDebug("%s", buf.data().constData());
+
+                qDebug("%u left in the worklist", _worklist->size());
             }
 
             if (!run(s)) {
@@ -2341,6 +2213,7 @@ public:
                     QTextStream qout(&buf);
                     qout<<"Pushing back stmt: ";
                     IRPrinter(&qout).print(s);
+                    qout.flush();
                     qDebug("%s", buf.data().constData());
                 }
             } else {
@@ -2350,6 +2223,7 @@ public:
                     QTextStream qout(&buf);
                     qout<<"Finished: ";
                     IRPrinter(&qout).print(s);
+                    qout.flush();
                     qDebug("%s", buf.data().constData());
                 }
             }
@@ -2373,7 +2247,9 @@ private:
     bool run(Stmt *s) {
         TypingResult ty;
         std::swap(_ty, ty);
-        s->accept(this);
+        std::swap(_currentStmt, s);
+        _currentStmt->accept(this);
+        std::swap(_currentStmt, s);
         std::swap(_ty, ty);
         return ty.fullyTyped;
     }
@@ -2407,11 +2283,16 @@ private:
                         QTextStream qout(&buf);
                         qout << "Pushing back dependent stmt: ";
                         IRPrinter(&qout).print(s);
+                        qout.flush();
                         qDebug("%s", buf.data().constData());
                     }
                 }
 
-                *_worklist += _defUses.uses(*t);
+                for (Stmt *s : qAsConst(_defUses.uses(*t))) {
+                    if (s != _currentStmt) {
+                        *_worklist += s;
+                    }
+                }
             }
         } else {
             e->type = (Type) ty.type;
@@ -2547,7 +2428,7 @@ protected:
 
         if (_ty.fullyTyped && _ty.type.memberResolver && _ty.type.memberResolver->isValid()) {
             MemberExpressionResolver *resolver = _ty.type.memberResolver;
-            _ty.type.type = resolver->resolveMember(qmlEngine, resolver, e);
+            _ty.type = resolver->resolveMember(qmlEngine, resolver, e);
         } else
             _ty.type = VarType;
     }
@@ -2569,9 +2450,9 @@ protected:
     virtual void visitCJump(CJump *s) { _ty = run(s->cond); }
     virtual void visitRet(Ret *s) { _ty = run(s->expr); }
     virtual void visitPhi(Phi *s) {
-        _ty = run(s->d->incoming[0]);
-        for (int i = 1, ei = s->d->incoming.size(); i != ei; ++i) {
-            TypingResult ty = run(s->d->incoming[i]);
+        _ty = run(s->incoming[0]);
+        for (int i = 1, ei = s->incoming.size(); i != ei; ++i) {
+            TypingResult ty = run(s->incoming[i]);
             if (!ty.fullyTyped && _ty.fullyTyped) {
                 // When one of the temps not fully typed, we already know that we cannot completely type this node.
                 // So, pick the type we calculated upto this point, and wait until the unknown one will be typed.
@@ -2834,12 +2715,12 @@ public:
 
     void run(IR::Function *f, StatementWorklist &worklist) {
         _f = f;
-        foreach (BasicBlock *bb, f->basicBlocks()) {
+        for (BasicBlock *bb : f->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
             _conversions.clear();
 
-            foreach (Stmt *s, bb->statements()) {
+            for (Stmt *s : bb->statements()) {
                 _currStmt = s;
                 s->accept(this);
             }
@@ -2890,7 +2771,7 @@ public:
                     _defUses.addUse(*source, conversion.stmt);
 
                     if (Phi *phi = conversion.stmt->asPhi()) {
-                        int idx = phi->d->incoming.indexOf(t);
+                        int idx = phi->incoming.indexOf(t);
                         Q_ASSERT(idx != -1);
                         bb->in[idx]->insertStatementBeforeTerminator(convCall);
                     } else {
@@ -3042,14 +2923,15 @@ protected:
     virtual void visitRet(Ret *s) { run(s->expr); }
     virtual void visitPhi(Phi *s) {
         Type ty = s->targetTemp->type;
-        for (int i = 0, ei = s->d->incoming.size(); i != ei; ++i)
-            run(s->d->incoming[i], ty);
+        for (int i = 0, ei = s->incoming.size(); i != ei; ++i)
+            run(s->incoming[i], ty);
     }
 };
 
 void splitCriticalEdges(IR::Function *f, DominatorTree &df, StatementWorklist &worklist, DefUses &defUses)
 {
-    foreach (BasicBlock *toBB, f->basicBlocks()) {
+    const QVector<BasicBlock *> copy = f->basicBlocks();
+    for (BasicBlock *toBB : copy) {
         if (toBB->isRemoved())
             continue;
         if (toBB->in.size() < 2)
@@ -3117,7 +2999,7 @@ void splitCriticalEdges(IR::Function *f, DominatorTree &df, StatementWorklist &w
             df.setImmediateDominator(newBB, fromBB);
 
             bool toNeedsNewIdom = true;
-            foreach (BasicBlock *bb, toBB->in) {
+            for (BasicBlock *bb : toBB->in) {
                 if (bb != newBB && !df.dominates(toBB, bb)) {
                     toNeedsNewIdom = false;
                     break;
@@ -3227,7 +3109,7 @@ public:
 
             backedges.clear();
 
-            foreach (BasicBlock *in, bb->in)
+            for (BasicBlock *in : bb->in)
                 if (dt.dominates(bb, in))
                     backedges.push_back(in);
 
@@ -3304,7 +3186,7 @@ private:
                 // those predecessors are not in the current subloop. It might be the case
                 // that they are in other loops, which we will then add as a subloop to the
                 // current loop.
-                foreach (BasicBlock *predIn, predIt->in)
+                for (BasicBlock *predIn : predIt->in)
                     if (predIn->containingGroup() != subloop)
                         worklist.push_back(predIn);
             } else {
@@ -3315,7 +3197,7 @@ private:
                 predIt->setContainingGroup(loopHead);
 
                 // Add all incoming edges to the worklist.
-                foreach (BasicBlock *bb, predIt->in)
+                for (BasicBlock *bb : predIt->in)
                     worklist.push_back(bb);
             }
         }
@@ -3327,7 +3209,7 @@ private:
 
     void createLoopInfos(IR::Function *function)
     {
-        foreach (BasicBlock *bb, function->basicBlocks()) {
+        for (BasicBlock *bb : function->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
             if (BasicBlock *loopHeader = bb->containingGroup())
@@ -3400,7 +3282,7 @@ class BlockScheduler
     {
         Q_ASSERT(candidate->containingGroup() == currentGroup.group);
 
-        foreach (BasicBlock *in, candidate->in) {
+        for (BasicBlock *in : candidate->in) {
             if (emitted.alreadyProcessed(in))
                 continue;
 
@@ -3510,7 +3392,7 @@ public:
 void checkCriticalEdges(QVector<BasicBlock *> basicBlocks) {
     foreach (BasicBlock *bb, basicBlocks) {
         if (bb && bb->out.size() > 1) {
-            foreach (BasicBlock *bb2, bb->out) {
+            for (BasicBlock *bb2 : bb->out) {
                 if (bb2 && bb2->in.size() > 1) {
                     qDebug() << "found critical edge between block"
                              << bb->index() << "and block" << bb2->index();
@@ -3545,28 +3427,28 @@ static void cleanupBasicBlocks(IR::Function *function)
 
         reachableBlocks.setBit(bb->index());
 
-        foreach (BasicBlock *outBB, bb->out) {
+        for (BasicBlock *outBB : bb->out) {
             if (!reachableBlocks.at(outBB->index()))
                 postponed.append(outBB);
         }
     }
 
-    foreach (BasicBlock *bb, function->basicBlocks()) {
+    for (BasicBlock *bb : function->basicBlocks()) {
         if (bb->isRemoved()) // the block has already been removed, so ignore it
             continue;
         if (reachableBlocks.at(bb->index())) // the block is reachable, so ignore it
             continue;
 
-        foreach (BasicBlock *outBB, bb->out) {
+        for (BasicBlock *outBB : bb->out) {
             if (outBB->isRemoved() || !reachableBlocks.at(outBB->index()))
                 continue; // We do not need to unlink from blocks that are scheduled to be removed.
 
             int idx = outBB->in.indexOf(bb);
             if (idx != -1) {
                 outBB->in.remove(idx);
-                foreach (Stmt *s, outBB->statements()) {
+                for (Stmt *s : outBB->statements()) {
                     if (Phi *phi = s->asPhi())
-                        phi->d->incoming.remove(idx);
+                        phi->incoming.remove(idx);
                     else
                         break;
                 }
@@ -3581,9 +3463,9 @@ static void cleanupBasicBlocks(IR::Function *function)
 
 inline Const *isConstPhi(Phi *phi)
 {
-    if (Const *c = phi->d->incoming[0]->asConst()) {
-        for (int i = 1, ei = phi->d->incoming.size(); i != ei; ++i) {
-            if (Const *cc = phi->d->incoming[i]->asConst()) {
+    if (Const *c = phi->incoming[0]->asConst()) {
+        for (int i = 1, ei = phi->incoming.size(); i != ei; ++i) {
+            if (Const *cc = phi->incoming[i]->asConst()) {
                 if (c->value != cc->value)
                     return 0;
                 if (!(c->type == cc->type || (c->type & NumberType && cc->type & NumberType)))
@@ -3684,8 +3566,8 @@ protected:
     virtual void visitCJump(CJump *s) { check(s->cond); }
     virtual void visitRet(Ret *s) { check(s->expr); }
     virtual void visitPhi(Phi *s) {
-        for (int i = 0, ei = s->d->incoming.size(); i != ei; ++i)
-            check(s->d->incoming[i]);
+        for (int i = 0, ei = s->incoming.size(); i != ei; ++i)
+            check(s->incoming[i]);
     }
 
 private:
@@ -3746,11 +3628,11 @@ void unlink(BasicBlock *from, BasicBlock *to, IR::Function *func, DefUses &defUs
                 if (!outStmt)
                     continue;
                 if (Phi *phi = outStmt->asPhi()) {
-                    if (Temp *t = phi->d->incoming[idx]->asTemp()) {
+                    if (Temp *t = phi->incoming[idx]->asTemp()) {
                         defUses.removeUse(phi, *t);
                         W += defUses.defStmt(*t);
                     }
-                    phi->d->incoming.remove(idx);
+                    phi->incoming.remove(idx);
                     W += phi;
                 } else {
                     break;
@@ -3800,14 +3682,14 @@ void unlink(BasicBlock *from, BasicBlock *to, IR::Function *func, DefUses &defUs
                 continue;
 
             // unlink all incoming edges
-            foreach (BasicBlock *in, bb->in) {
+            for (BasicBlock *in : bb->in) {
                 int idx = in->out.indexOf(bb);
                 if (idx != -1)
                     in->out.remove(idx);
             }
 
             // unlink all outgoing edges, including "arguments" to phi statements
-            foreach (BasicBlock *out, bb->out) {
+            for (BasicBlock *out : bb->out) {
                 if (out->isRemoved())
                     continue;
 
@@ -3823,7 +3705,7 @@ void unlink(BasicBlock *from, BasicBlock *to, IR::Function *func, DefUses &defUs
             }
 
             // unlink all defs/uses from the statements in the basic block
-            foreach (Stmt *s, bb->statements()) {
+            for (Stmt *s : bb->statements()) {
                 if (!s)
                     continue;
 
@@ -3938,7 +3820,7 @@ void cfg2dot(IR::Function *f, const QVector<LoopDetection::LoopInfo *> &loops =
             Util(qout).genLoop(l);
     }
 
-    foreach (BasicBlock *bb, f->basicBlocks()) {
+    for (BasicBlock *bb : f->basicBlocks()) {
         if (bb->isRemoved())
             continue;
 
@@ -3949,7 +3831,7 @@ void cfg2dot(IR::Function *f, const QVector<LoopDetection::LoopInfo *> &loops =
         else
             qout << ", shape=circle";
         qout << "];\n";
-        foreach (BasicBlock *out, bb->out)
+        for (BasicBlock *out : bb->out)
             qout << "  L" << idx << " -> L" << out->index() << "\n";
     }
 
@@ -3987,9 +3869,9 @@ void optimizeSSA(StatementWorklist &W, DefUses &defUses, DominatorTree &df)
             }
 
             // copy propagation:
-            if (phi->d->incoming.size() == 1) {
+            if (phi->incoming.size() == 1) {
                 Temp *t = phi->targetTemp;
-                Expr *e = phi->d->incoming.first();
+                Expr *e = phi->incoming.first();
 
                 QVector<Stmt *> newT2Uses;
                 replaceUses(t, e, W, &newT2Uses);
@@ -4420,14 +4302,14 @@ private:
     void buildIntervals(BasicBlock *bb, BasicBlock *loopEnd)
     {
         LiveRegs live;
-        foreach (BasicBlock *successor, bb->out) {
+        for (BasicBlock *successor : bb->out) {
             live.unite(_liveIn[successor->index()]);
             const int bbIndex = successor->in.indexOf(bb);
             Q_ASSERT(bbIndex >= 0);
 
-            foreach (Stmt *s, successor->statements()) {
+            for (Stmt *s : successor->statements()) {
                 if (Phi *phi = s->asPhi()) {
-                    if (Temp *t = phi->d->incoming.at(bbIndex)->asTemp())
+                    if (Temp *t = phi->incoming.at(bbIndex)->asTemp())
                         live.insert(*t);
                 } else {
                     break;
@@ -4435,7 +4317,7 @@ private:
             }
         }
 
-        QVector<Stmt *> statements = bb->statements();
+        const QVector<Stmt *> &statements = bb->statements();
 
         foreach (const Temp &opd, live)
             interval(&opd).addRange(start(bb), end(bb));
@@ -4483,7 +4365,7 @@ void removeUnreachleBlocks(IR::Function *function)
 {
     QVector<BasicBlock *> newSchedule;
     newSchedule.reserve(function->basicBlockCount());
-    foreach (BasicBlock *bb, function->basicBlocks())
+    for (BasicBlock *bb : function->basicBlocks())
         if (!bb->isRemoved())
             newSchedule.append(bb);
     function->setScheduledBlocks(newSchedule);
@@ -4528,9 +4410,9 @@ public:
             }
         }
 
-        foreach (BasicBlock *bb, function->basicBlocks())
+        for (BasicBlock *bb : function->basicBlocks())
             if (!bb->isRemoved())
-                foreach (Stmt *s, bb->statements())
+                for (Stmt *s : bb->statements())
                     s->accept(this);
 
         if (convertArgs && function->formals.size() > 0)
@@ -4614,7 +4496,7 @@ public:
     {
         block = new BasicBlock(originalBlock->function, 0);
 
-        foreach (Stmt *s, originalBlock->statements()) {
+        for (Stmt *s : originalBlock->statements()) {
             s->accept(this);
             clonedStmt->location = s->location;
         }
@@ -4644,9 +4526,8 @@ protected:
         clonedStmt = phi;
 
         phi->targetTemp = clone(stmt->targetTemp);
-        phi->d = new Phi::Data;
-        foreach (Expr *in, stmt->d->incoming)
-            phi->d->incoming.append(clone(in));
+        foreach (Expr *in, stmt->incoming)
+            phi->incoming.append(clone(in));
         block->appendStatement(phi);
     }
 
@@ -4731,7 +4612,8 @@ private:
         // the terminators will automatically insert that edge). The blocks where the originals
         // pointed to will have an extra incoming edge from the copied blocks.
 
-        foreach (BasicBlock *in, loop->loopHeader->in) {
+        BasicBlock::IncomingEdges inCopy = loop->loopHeader->in;
+        for (BasicBlock *in : inCopy) {
             if (unpeeled.loopHeader != in // this can happen for really tight loops (where there are no body blocks). This is a back-edge in that case.
                     && !unpeeled.loopBody.contains(in) // if the edge is not coming from within the copied set, leave it alone
                     && !dt.dominates(loop->loopHeader, in)) // an edge coming from within the loop (so a back-edge): this is handled when rewiring all outgoing edges
@@ -4805,7 +4687,7 @@ static void verifyCFG(IR::Function *function)
     if (!DoVerification)
         return;
 
-    foreach (BasicBlock *bb, function->basicBlocks()) {
+    for (BasicBlock *bb : function->basicBlocks()) {
         if (bb->isRemoved()) {
             Q_ASSERT(bb->in.isEmpty());
             Q_ASSERT(bb->out.isEmpty());
@@ -4837,14 +4719,14 @@ static void verifyCFG(IR::Function *function)
         }
 
         // Check the outgoing edges:
-        foreach (BasicBlock *out, bb->out) {
+        for (BasicBlock *out : bb->out) {
             Q_UNUSED(out);
             Q_ASSERT(!out->isRemoved());
             Q_ASSERT(out->in.contains(bb));
         }
 
         // Check the incoming edges:
-        foreach (BasicBlock *in, bb->in) {
+        for (BasicBlock *in : bb->in) {
             Q_UNUSED(in);
             Q_ASSERT(!in->isRemoved());
             Q_ASSERT(in->out.contains(bb));
@@ -4861,7 +4743,7 @@ static void verifyImmediateDominators(const DominatorTree &dt, IR::Function *fun
     dt.dumpImmediateDominators();
     DominatorTree referenceTree(function);
 
-    foreach (BasicBlock *bb, function->basicBlocks()) {
+    for (BasicBlock *bb : function->basicBlocks()) {
         if (bb->isRemoved())
             continue;
 
@@ -4882,11 +4764,11 @@ static void verifyNoPointerSharing(IR::Function *function)
     public:
         void operator()(IR::Function *f)
         {
-            foreach (BasicBlock *bb, f->basicBlocks()) {
+            for (BasicBlock *bb : f->basicBlocks()) {
                 if (bb->isRemoved())
                     continue;
 
-                foreach (Stmt *s, bb->statements())
+                for (Stmt *s : bb->statements())
                     s->accept(this);
             }
         }
@@ -4901,7 +4783,7 @@ static void verifyNoPointerSharing(IR::Function *function)
         {
             check(s);
             s->targetTemp->accept(this);
-            foreach (Expr *e, s->d->incoming)
+            foreach (Expr *e, s->incoming)
                 e->accept(this);
         }
 
@@ -4950,11 +4832,11 @@ class RemoveLineNumbers: public SideEffectsChecker, public StmtVisitor
 public:
     static void run(IR::Function *function)
     {
-        foreach (BasicBlock *bb, function->basicBlocks()) {
+        for (BasicBlock *bb : function->basicBlocks()) {
             if (bb->isRemoved())
                 continue;
 
-            foreach (Stmt *s, bb->statements()) {
+            for (Stmt *s : bb->statements()) {
                 if (!hasSideEffects(s)) {
                     s->location = QQmlJS::AST::SourceLocation();
                 }
@@ -5166,13 +5048,13 @@ LifeTimeIntervals::LifeTimeIntervals(IR::Function *function)
 // basic-block.
 void LifeTimeIntervals::renumber(IR::Function *function)
 {
-    foreach (BasicBlock *bb, function->basicBlocks()) {
+    for (BasicBlock *bb : function->basicBlocks()) {
         if (bb->isRemoved())
             continue;
 
         _basicBlockPosition[bb->index()].start = _lastPosition + 1;
 
-        foreach (Stmt *s, bb->statements()) {
+        for (Stmt *s : bb->statements()) {
             if (s->asPhi())
                 continue;
 
@@ -5202,7 +5084,7 @@ void Optimizer::run(QQmlEnginePrivate *qmlEngine, bool doTypeInference, bool pee
 
     function->removeSharedExpressions();
     int statementCount = 0;
-    foreach (BasicBlock *bb, function->basicBlocks())
+    for (BasicBlock *bb : function->basicBlocks())
         if (!bb->isRemoved())
             statementCount += bb->statementCount();
 //    showMeTheCode(function);
@@ -5332,15 +5214,15 @@ void Optimizer::convertOutOfSSA() {
 
     // There should be no critical edges at this point.
 
-    foreach (BasicBlock *bb, function->basicBlocks()) {
+    for (BasicBlock *bb : function->basicBlocks()) {
         MoveMapping moves;
 
-        foreach (BasicBlock *successor, bb->out) {
+        for (BasicBlock *successor : bb->out) {
             const int inIdx = successor->in.indexOf(bb);
             Q_ASSERT(inIdx >= 0);
-            foreach (Stmt *s, successor->statements()) {
+            for (Stmt *s : successor->statements()) {
                 if (Phi *phi = s->asPhi()) {
-                    moves.add(clone(phi->d->incoming[inIdx], function),
+                    moves.add(clone(phi->incoming[inIdx], function),
                               clone(phi->targetTemp, function)->asTemp());
                 } else {
                     break;
@@ -5368,7 +5250,7 @@ void Optimizer::convertOutOfSSA() {
         moves.insertMoves(bb, function, true);
     }
 
-    foreach (BasicBlock *bb, function->basicBlocks()) {
+    for (BasicBlock *bb : function->basicBlocks()) {
         while (!bb->isEmpty()) {
             if (bb->statements().first()->asPhi()) {
                 bb->removeStatement(0);
diff --git a/src/qml/debugger/qqmlabstractprofileradapter_p.h b/src/qml/debugger/qqmlabstractprofileradapter_p.h
index bd93da324d..1104608055 100644
--- a/src/qml/debugger/qqmlabstractprofileradapter_p.h
+++ b/src/qml/debugger/qqmlabstractprofileradapter_p.h
@@ -64,6 +64,8 @@ class Q_QML_PRIVATE_EXPORT QQmlAbstractProfilerAdapter : public QObject, public
     Q_OBJECT
 
 public:
+    static const int s_numMessagesPerBatch = 1000;
+
     QQmlAbstractProfilerAdapter(QObject *parent = 0) :
         QObject(parent), service(0), waiting(true), featuresEnabled(0) {}
     virtual ~QQmlAbstractProfilerAdapter() {}
diff --git a/src/qml/debugger/qqmldebug.cpp b/src/qml/debugger/qqmldebug.cpp
index 64a951d53b..9276bd0544 100644
--- a/src/qml/debugger/qqmldebug.cpp
+++ b/src/qml/debugger/qqmldebug.cpp
@@ -134,22 +134,11 @@ void QQmlDebuggingEnabler::setServices(const QStringList &services)
  */
 bool QQmlDebuggingEnabler::startTcpDebugServer(int port, StartMode mode, const QString &hostName)
 {
-#ifndef QQML_NO_DEBUG_PROTOCOL
-    QQmlDebugConnector::setPluginKey(QLatin1String("QQmlDebugServer"));
-    QQmlDebugConnector *connector = QQmlDebugConnector::instance();
-    if (connector) {
-        QVariantHash configuration;
-        configuration[QLatin1String("portFrom")] = configuration[QLatin1String("portTo")] = port;
-        configuration[QLatin1String("block")] = (mode == WaitForClient);
-        configuration[QLatin1String("hostAddress")] = hostName;
-        return connector->open(configuration);
-    }
-#else
-    Q_UNUSED(port);
-    Q_UNUSED(mode);
-    Q_UNUSED(hostName);
-#endif
-    return false;
+    QVariantHash configuration;
+    configuration[QLatin1String("portFrom")] = configuration[QLatin1String("portTo")] = port;
+    configuration[QLatin1String("block")] = (mode == WaitForClient);
+    configuration[QLatin1String("hostAddress")] = hostName;
+    return startDebugConnector(QLatin1String("QQmlDebugServer"), configuration);
 }
 
 /*!
@@ -164,18 +153,33 @@ bool QQmlDebuggingEnabler::startTcpDebugServer(int port, StartMode mode, const Q
  */
 bool QQmlDebuggingEnabler::connectToLocalDebugger(const QString &socketFileName, StartMode mode)
 {
+    QVariantHash configuration;
+    configuration[QLatin1String("fileName")] = socketFileName;
+    configuration[QLatin1String("block")] = (mode == WaitForClient);
+    return startDebugConnector(QLatin1String("QQmlDebugServer"), configuration);
+}
+
+/*!
+ * \since 5.7
+ *
+ * Enables debugging for QML engines created after calling this function. A debug connector plugin
+ * specified by \a pluginName will be loaded and started using the given \a configuration. Supported
+ * configuration entries and their semantics depend on the plugin being loaded. You can only start
+ * one debug connector at a time. A debug connector may have already been started if the
+ * -qmljsdebugger= command line argument was given. This method returns \c true if a new debug
+ * connector was successfully started, or \c false otherwise.
+ */
+bool QQmlDebuggingEnabler::startDebugConnector(const QString &pluginName,
+                                               const QVariantHash &configuration)
+{
 #ifndef QQML_NO_DEBUG_PROTOCOL
-    QQmlDebugConnector::setPluginKey(QLatin1String("QQmlDebugServer"));
+    QQmlDebugConnector::setPluginKey(pluginName);
     QQmlDebugConnector *connector = QQmlDebugConnector::instance();
-    if (connector) {
-        QVariantHash configuration;
-        configuration[QLatin1String("fileName")] = socketFileName;
-        configuration[QLatin1String("block")] = (mode == WaitForClient);
+    if (connector)
         return connector->open(configuration);
-    }
 #else
-    Q_UNUSED(fileName);
-    Q_UNUSED(mode);
+    Q_UNUSED(pluginName);
+    Q_UNUSED(configuration);
 #endif
     return false;
 }
diff --git a/src/qml/debugger/qqmldebug.h b/src/qml/debugger/qqmldebug.h
index eebebefe62..660b9e4d46 100644
--- a/src/qml/debugger/qqmldebug.h
+++ b/src/qml/debugger/qqmldebug.h
@@ -42,6 +42,7 @@
 
 #include <QtQml/qtqmlglobal.h>
 #include <QtCore/qstring.h>
+#include <QtCore/qvariant.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -65,6 +66,8 @@ struct Q_QML_EXPORT QQmlDebuggingEnabler
                                     const QString &hostName = QString());
     static bool connectToLocalDebugger(const QString &socketFileName,
                                        StartMode mode = DoNotWaitForClient);
+    static bool startDebugConnector(const QString &pluginName,
+                                    const QVariantHash &configuration = QVariantHash());
 };
 
 // Execute code in constructor before first QQmlEngine is instantiated
diff --git a/src/qml/debugger/qqmldebugconnector.cpp b/src/qml/debugger/qqmldebugconnector.cpp
index 6edd28ea01..e6d1a218ad 100644
--- a/src/qml/debugger/qqmldebugconnector.cpp
+++ b/src/qml/debugger/qqmldebugconnector.cpp
@@ -127,18 +127,15 @@ QQmlDebugConnector *QQmlDebugConnector::instance()
     }
 
     if (!params->instance) {
-        const QString serverConnector = QStringLiteral("QQmlDebugServer");
-        const QString nativeConnector = QStringLiteral("QQmlNativeDebugConnector");
-        const bool isNative = params->arguments.startsWith(QLatin1String("native"));
         if (!params->pluginKey.isEmpty()) {
-            if (params->pluginKey == serverConnector || params->pluginKey == nativeConnector)
-                params->instance = loadQQmlDebugConnector(params->pluginKey);
-            else
-                return 0; // We cannot load anything else, yet
+            params->instance = loadQQmlDebugConnector(params->pluginKey);
         } else if (params->arguments.isEmpty()) {
             return 0; // no explicit class name given and no command line arguments
         } else {
-            params->instance = loadQQmlDebugConnector(isNative ? nativeConnector : serverConnector);
+            params->instance = loadQQmlDebugConnector(
+                        params->arguments.startsWith(QLatin1String("native")) ?
+                            QStringLiteral("QQmlNativeDebugConnector") :
+                            QStringLiteral("QQmlDebugServer"));
         }
 
         if (params->instance) {
diff --git a/src/qml/doc/src/qmltypereference.qdoc b/src/qml/doc/src/qmltypereference.qdoc
index 31133c862f..f32574fcc1 100644
--- a/src/qml/doc/src/qmltypereference.qdoc
+++ b/src/qml/doc/src/qmltypereference.qdoc
@@ -55,7 +55,7 @@ are also provided by the \c QtQuick namespace which may be imported as
 follows:
 
 \qml
-import QtQuick 2.5
+import QtQuick 2.7
 \endqml
 
 See the \l{Qt Quick} module documentation for more information about the \c
diff --git a/src/qml/jit/qv4regalloc.cpp b/src/qml/jit/qv4regalloc.cpp
index a6e085a913..131e0a5b0a 100644
--- a/src/qml/jit/qv4regalloc.cpp
+++ b/src/qml/jit/qv4regalloc.cpp
@@ -180,9 +180,9 @@ public:
         _calls.reserve(function->statementCount() / 3);
         _hints.resize(function->tempCount);
 
-        foreach (BasicBlock *bb, function->basicBlocks()) {
+        for (BasicBlock *bb : function->basicBlocks()) {
             _currentBB = bb;
-            foreach (Stmt *s, bb->statements()) {
+            for (Stmt *s : bb->statements()) {
                 _currentStmt = s;
                 s->accept(this);
             }
@@ -702,8 +702,8 @@ protected: // IRDecoder
     virtual void visitPhi(IR::Phi *s)
     {
         addDef(s->targetTemp, true);
-        for (int i = 0, ei = s->d->incoming.size(); i < ei; ++i) {
-            Expr *e = s->d->incoming.at(i);
+        for (int i = 0, ei = s->incoming.size(); i < ei; ++i) {
+            Expr *e = s->incoming.at(i);
             if (Temp *t = e->asTemp()) {
                 // The actual use of an incoming value in a phi node is right before the terminator
                 // of the other side of the incoming edge.
@@ -821,8 +821,8 @@ class ResolutionPhase: protected StmtVisitor, protected ExprVisitor {
     const QVector<const RegisterInfo *> &_fpRegs;
 
     Stmt *_currentStmt;
-    QVector<Move *> _loads;
-    QVector<Move *> _stores;
+    std::vector<Move *> _loads;
+    std::vector<Move *> _stores;
 
     QHash<BasicBlock *, QList<const LifeTimeInterval *> > _liveAtStart;
     QHash<BasicBlock *, QList<const LifeTimeInterval *> > _liveAtEnd;
@@ -872,7 +872,7 @@ private:
     {
         QVector<Stmt *> newStatements;
 
-        foreach (BasicBlock *bb, _function->basicBlocks()) {
+        for (BasicBlock *bb : _function->basicBlocks()) {
             _currentStmt = 0;
 
             QVector<Stmt *> statements = bb->statements();
@@ -892,13 +892,13 @@ private:
                 else
                     addNewIntervals(defPosition(_currentStmt));
                 _currentStmt->accept(this);
-                foreach (Move *load, _loads)
+                for (Move *load : _loads)
                     newStatements.append(load);
                 if (_currentStmt->asPhi())
                     newStatements.prepend(_currentStmt);
                 else
                     newStatements.append(_currentStmt);
-                foreach (Move *store, _stores)
+                for (Move *store : _stores)
                     newStatements.append(store);
             }
 
@@ -912,7 +912,7 @@ private:
                 os << "Intervals live at the start of L" << bb->index() << ":" << endl;
                 if (_liveAtStart[bb].isEmpty())
                     os << "\t(none)" << endl;
-                foreach (const LifeTimeInterval *i, _liveAtStart[bb]) {
+                for (const LifeTimeInterval *i : _liveAtStart.value(bb)) {
                     os << "\t";
                     i->dump(os);
                     os << endl;
@@ -920,7 +920,7 @@ private:
                 os << "Intervals live at the end of L" << bb->index() << ":" << endl;
                 if (_liveAtEnd[bb].isEmpty())
                     os << "\t(none)" << endl;
-                foreach (const LifeTimeInterval *i, _liveAtEnd[bb]) {
+                for (const LifeTimeInterval *i : _liveAtEnd.value(bb)) {
                     os << "\t";
                     i->dump(os);
                     os << endl;
@@ -943,7 +943,7 @@ private:
         Q_ASSERT(pReg);
         int spillSlot = _assignedSpillSlots[i->temp().index];
         if (spillSlot != RegisterAllocator::InvalidSpillSlot)
-            _stores.append(generateSpill(spillSlot, i->temp().type, pReg->reg<int>()));
+            _stores.push_back(generateSpill(spillSlot, i->temp().type, pReg->reg<int>()));
     }
 
     void addNewIntervals(int position)
@@ -976,15 +976,15 @@ private:
 
     void resolve()
     {
-        foreach (BasicBlock *bb, _function->basicBlocks()) {
-            foreach (BasicBlock *bbOut, bb->out)
+        for (BasicBlock *bb : _function->basicBlocks()) {
+            for (BasicBlock *bbOut : bb->out)
                 resolveEdge(bb, bbOut);
         }
     }
 
     Phi *findDefPhi(const Temp &t, BasicBlock *bb) const
     {
-        foreach (Stmt *s, bb->statements()) {
+        for (Stmt *s : bb->statements()) {
             Phi *phi = s->asPhi();
             if (!phi)
                 return 0;
@@ -1017,21 +1017,21 @@ private:
         int successorStart = _intervals->startPosition(successor);
         Q_ASSERT(successorStart > 0);
 
-        foreach (const LifeTimeInterval *it, _liveAtStart[successor]) {
+        for (const LifeTimeInterval *it : _liveAtStart.value(successor)) {
             bool isPhiTarget = false;
             Expr *moveFrom = 0;
 
             if (it->start() == successorStart) {
                 if (Phi *phi = findDefPhi(it->temp(), successor)) {
                     isPhiTarget = true;
-                    Expr *opd = phi->d->incoming[successor->in.indexOf(predecessor)];
+                    Expr *opd = phi->incoming[successor->in.indexOf(predecessor)];
                     if (opd->asConst()) {
                         moveFrom = opd;
                     } else {
                         Temp *t = opd->asTemp();
                         Q_ASSERT(t);
 
-                        foreach (const LifeTimeInterval *it2, _liveAtEnd[predecessor]) {
+                        for (const LifeTimeInterval *it2 : _liveAtEnd.value(predecessor)) {
                             if (it2->temp() == *t
                                     && it2->reg() != LifeTimeInterval::InvalidRegister
                                     && it2->covers(predecessorEnd)) {
@@ -1046,7 +1046,7 @@ private:
                     }
                 }
             } else {
-                foreach (const LifeTimeInterval *predIt, _liveAtEnd[predecessor]) {
+                for (const LifeTimeInterval *predIt : _liveAtEnd.value(predecessor)) {
                     if (predIt->temp() == it->temp()) {
                         if (predIt->reg() != LifeTimeInterval::InvalidRegister
                                 && predIt->covers(predecessorEnd)) {
@@ -1191,7 +1191,7 @@ protected:
             Q_ASSERT(i->isSplitFromInterval());
             const RegisterInfo *pReg = platformRegister(*i);
             Q_ASSERT(pReg);
-            _loads.append(generateUnspill(i->temp(), pReg->reg<int>()));
+            _loads.push_back(generateUnspill(i->temp(), pReg->reg<int>()));
         }
 
         if (i->reg() != LifeTimeInterval::InvalidRegister &&
@@ -1303,7 +1303,7 @@ void RegisterAllocator::run(IR::Function *function, const Optimizer &opt)
         qout << "Ranges:" << endl;
         QVector<LifeTimeInterval *> intervals = _unhandled;
         std::reverse(intervals.begin(), intervals.end());
-        foreach (const LifeTimeInterval *r, intervals) {
+        for (const LifeTimeInterval *r : qAsConst(intervals)) {
             r->dump(qout);
             qout << endl;
         }
@@ -1490,11 +1490,11 @@ void RegisterAllocator::linearScan()
         }
     }
 
-    foreach (LifeTimeInterval *r, _active)
+    for (LifeTimeInterval *r : qAsConst(_active))
         if (!r->isFixedInterval())
             _handled.append(r);
     _active.clear();
-    foreach (LifeTimeInterval *r, _inactive)
+    for (LifeTimeInterval *r : qAsConst(_inactive))
         if (!r->isFixedInterval())
             _handled.append(r);
     _inactive.clear();
@@ -1922,7 +1922,7 @@ void RegisterAllocator::dump(IR::Function *function) const
     qout << "Ranges:" << endl;
     QVector<LifeTimeInterval *> handled = _handled;
     std::sort(handled.begin(), handled.end(), LifeTimeInterval::lessThanForTemp);
-    foreach (const LifeTimeInterval *r, handled) {
+    for (const LifeTimeInterval *r : qAsConst(handled)) {
         r->dump(qout);
         qout << endl;
     }
diff --git a/src/qml/jsapi/qjsengine.h b/src/qml/jsapi/qjsengine.h
index 300990873d..6ecd0c7ec0 100644
--- a/src/qml/jsapi/qjsengine.h
+++ b/src/qml/jsapi/qjsengine.h
@@ -111,7 +111,7 @@ private:
     friend inline bool qjsvalue_cast_helper(const QJSValue &, int, void *);
 
 protected:
-    QJSEngine(QJSEnginePrivate &dd, QObject *parent = 0);
+    QJSEngine(QJSEnginePrivate &dd, QObject *parent = Q_NULLPTR);
 
 private:
     QV8Engine *d;
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 317eb7a8a7..55ea1f91c3 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -576,15 +576,6 @@ ExecutionContext *ExecutionEngine::pushGlobalContext()
     return currentContext;
 }
 
-ExecutionContext *ExecutionEngine::parentContext(ExecutionContext *context) const
-{
-    Value *offset = static_cast<Value *>(context) + 1;
-    Q_ASSERT(offset->isInteger());
-    int o = offset->integerValue();
-    return o ? context - o : 0;
-}
-
-
 Heap::Object *ExecutionEngine::newObject()
 {
     return memoryManager->allocObject<Object>();
@@ -770,27 +761,6 @@ Heap::Object *ExecutionEngine::newForEachIteratorObject(Object *o)
     return obj->d();
 }
 
-Heap::QmlContext *ExecutionEngine::qmlContext() const
-{
-    Heap::ExecutionContext *ctx = current;
-
-    // get the correct context when we're within a builtin function
-    if (ctx->type == Heap::ExecutionContext::Type_SimpleCallContext && !ctx->outer)
-        ctx = parentContext(currentContext)->d();
-
-    if (!ctx->outer)
-        return 0;
-
-    while (ctx->outer && ctx->outer->type != Heap::ExecutionContext::Type_GlobalContext)
-        ctx = ctx->outer;
-
-    Q_ASSERT(ctx);
-    if (ctx->type != Heap::ExecutionContext::Type_QmlContext)
-        return 0;
-
-    return static_cast<Heap::QmlContext *>(ctx);
-}
-
 QObject *ExecutionEngine::qmlScopeObject() const
 {
     Heap::QmlContext *ctx = qmlContext();
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index 12ed98e6e7..7da4a1c3c1 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -500,6 +500,35 @@ inline void ExecutionEngine::popContext()
     current = currentContext->d();
 }
 
+inline ExecutionContext *ExecutionEngine::parentContext(ExecutionContext *context) const
+{
+    Value *offset = static_cast<Value *>(context) + 1;
+    Q_ASSERT(offset->isInteger());
+    int o = offset->integerValue();
+    return o ? context - o : 0;
+}
+
+inline Heap::QmlContext *ExecutionEngine::qmlContext() const
+{
+    Heap::ExecutionContext *ctx = current;
+
+    // get the correct context when we're within a builtin function
+    if (ctx->type == Heap::ExecutionContext::Type_SimpleCallContext && !ctx->outer)
+        ctx = parentContext(currentContext)->d();
+
+    if (!ctx->outer)
+        return 0;
+
+    while (ctx->outer && ctx->outer->type != Heap::ExecutionContext::Type_GlobalContext)
+        ctx = ctx->outer;
+
+    Q_ASSERT(ctx);
+    if (ctx->type != Heap::ExecutionContext::Type_QmlContext)
+        return 0;
+
+    return static_cast<Heap::QmlContext *>(ctx);
+}
+
 inline
 void Heap::Base::mark(QV4::ExecutionEngine *engine)
 {
diff --git a/src/qml/jsruntime/qv4qobjectwrapper.cpp b/src/qml/jsruntime/qv4qobjectwrapper.cpp
index dd86c50270..470791fb00 100644
--- a/src/qml/jsruntime/qv4qobjectwrapper.cpp
+++ b/src/qml/jsruntime/qv4qobjectwrapper.cpp
@@ -141,8 +141,8 @@ struct ReadAccessor {
     {
         Q_ASSERT(property.accessors);
 
-        property.accessors->read(object, property.accessorData, output);
-        if (n) property.accessors->notifier(object, property.accessorData, n);
+        property.accessors->read(object, output);
+        if (n) property.accessors->notifier(object, n);
     }
 };
 
diff --git a/src/qml/jsruntime/qv4util_p.h b/src/qml/jsruntime/qv4util_p.h
index 3ffcc8a846..59c12c5e46 100644
--- a/src/qml/jsruntime/qv4util_p.h
+++ b/src/qml/jsruntime/qv4util_p.h
@@ -51,6 +51,9 @@
 //
 
 #include "qv4global_p.h"
+#include <QtCore/QBitArray>
+#include <algorithm>
+#include <vector>
 
 QT_BEGIN_NAMESPACE
 
@@ -76,6 +79,130 @@ private:
     TemporaryAssignment operator=(const TemporaryAssignment<T>&);
 };
 
+#if !defined(BROKEN_STD_VECTOR_BOOL_OR_BROKEN_STD_FIND)
+// Sanity:
+class BitVector
+{
+    std::vector<bool> bits;
+
+public:
+    BitVector(int size = 0, bool value = false)
+        : bits(size, value)
+    {}
+
+    void reserve(int size)
+    { bits.reserve(size); }
+
+    int size() const
+    {
+        Q_ASSERT(bits.size() < INT_MAX);
+        return static_cast<int>(bits.size());
+    }
+
+    void resize(int newSize)
+    { bits.resize(newSize); }
+
+    void resize(int newSize, bool newValue)
+    { bits.resize(newSize, newValue); }
+
+    void assign(int newSize, bool value)
+    { bits.assign(newSize, value); }
+
+    int findNext(int start, bool value, bool wrapAround) const
+    {
+        // The ++operator of std::vector<bool>::iterator in libc++ has a bug when using it on an
+        // iterator pointing to the last element. It will not be set to ::end(), but beyond
+        // that. (It will be set to the first multiple of the native word size that is bigger
+        // than size().)
+        //
+        // See http://llvm.org/bugs/show_bug.cgi?id=19663
+        //
+        // The work-around is to calculate the distance, and compare it to the size() to see if it's
+        // beyond the end, or take the minimum of the distance and the size.
+
+        size_t pos = std::distance(bits.begin(),
+                                   std::find(bits.begin() + start, bits.end(), value));
+        if (wrapAround && pos >= static_cast<size_t>(size()))
+            pos = std::distance(bits.begin(),
+                                std::find(bits.begin(), bits.begin() + start, value));
+
+        pos = qMin(pos, static_cast<size_t>(size()));
+
+        Q_ASSERT(pos <= static_cast<size_t>(size()));
+        Q_ASSERT(pos < INT_MAX);
+
+        return static_cast<int>(pos);
+    }
+
+    bool at(int idx) const
+    { return bits.at(idx); }
+
+    void setBit(int idx)
+    { bits[idx] = true; }
+
+    void clearBit(int idx)
+    { bits[idx] = false; }
+};
+#else // Insanity:
+class BitVector
+{
+    QBitArray bits;
+
+public:
+    BitVector(int size = 0, bool value = false)
+        : bits(size, value)
+    {}
+
+    void reserve(int size)
+    { Q_UNUSED(size); }
+
+    int size() const
+    { return bits.size(); }
+
+    void resize(int newSize)
+    { bits.resize(newSize); }
+
+    void resize(int newSize, bool newValue)
+    {
+        int oldSize = bits.size();
+        bits.resize(newSize);
+        bits.fill(newValue, oldSize, bits.size());
+    }
+
+    void assign(int newSize, bool value)
+    {
+        bits.resize(newSize);
+        bits.fill(value);
+    }
+
+    int findNext(int start, bool value, bool wrapAround) const
+    {
+        for (int i = start, ei = size(); i < ei; ++i) {
+            if (at(i) == value)
+                return i;
+        }
+
+        if (wrapAround) {
+            for (int i = 0, ei = start; i < ei; ++i) {
+                if (at(i) == value)
+                    return i;
+            }
+        }
+
+        return size();
+    }
+
+    bool at(int idx) const
+    { return bits.at(idx); }
+
+    void setBit(int idx)
+    { bits[idx] = true; }
+
+    void clearBit(int idx)
+    { bits[idx] = false; }
+};
+#endif
+
 }
 
 QT_END_NAMESPACE
diff --git a/src/qml/jsruntime/qv4value_p.h b/src/qml/jsruntime/qv4value_p.h
index e8320b33d2..514bdafb48 100644
--- a/src/qml/jsruntime/qv4value_p.h
+++ b/src/qml/jsruntime/qv4value_p.h
@@ -119,11 +119,14 @@ struct Q_QML_PRIVATE_EXPORT Value
     Q_ALWAYS_INLINE quint32 value() const { return _val >> 32; }
 #endif
 
-#ifdef QV4_USE_64_BIT_VALUE_ENCODING
+#if defined(V4_BOOTSTRAP)
+    Q_ALWAYS_INLINE Heap::Base *m() const { Q_UNREACHABLE(); return Q_NULLPTR; }
+    Q_ALWAYS_INLINE void setM(Heap::Base *b) { Q_UNUSED(b); Q_UNREACHABLE(); }
+#elif defined(QV4_USE_64_BIT_VALUE_ENCODING)
     Q_ALWAYS_INLINE Heap::Base *m() const { Heap::Base *b; memcpy(&b, &_val, 8); return b; }
     Q_ALWAYS_INLINE void setM(Heap::Base *b) { memcpy(&_val, &b, 8); }
 #else // !QV4_USE_64_BIT_VALUE_ENCODING
-    Q_ALWAYS_INLINE Heap::Base *m() const { Heap::Base *b; quint32 v = value(); memcpy(&b, &v, 4); return b; }
+    Q_ALWAYS_INLINE Heap::Base *m() const { Q_STATIC_ASSERT(sizeof(Heap::Base*) == sizeof(quint32)); Heap::Base *b; quint32 v = value(); memcpy(&b, &v, 4); return b; }
     Q_ALWAYS_INLINE void setM(Heap::Base *b) { quint32 v; memcpy(&v, &b, 4); setValue(v); }
 #endif
 
diff --git a/src/qml/parser/qqmljsmemorypool_p.h b/src/qml/parser/qqmljsmemorypool_p.h
index 3659271bc6..08609e2961 100644
--- a/src/qml/parser/qqmljsmemorypool_p.h
+++ b/src/qml/parser/qqmljsmemorypool_p.h
@@ -94,7 +94,7 @@ public:
     inline void *allocate(size_t size)
     {
         size = (size + 7) & ~7;
-        if (_ptr && (_ptr + size < _end)) {
+        if (Q_LIKELY(_ptr && (_ptr + size < _end))) {
             void *addr = _ptr;
             _ptr += size;
             return addr;
@@ -111,7 +111,7 @@ public:
     template <typename Tp> Tp *New() { return new (this->allocate(sizeof(Tp))) Tp(); }
 
 private:
-    void *allocate_helper(size_t size)
+    Q_NEVER_INLINE void *allocate_helper(size_t size)
     {
         Q_ASSERT(size < BLOCK_SIZE);
 
diff --git a/src/qml/qml/ftw/qhashedstring_p.h b/src/qml/qml/ftw/qhashedstring_p.h
index 4ddac0c2c6..6ff3e4a11b 100644
--- a/src/qml/qml/ftw/qhashedstring_p.h
+++ b/src/qml/qml/ftw/qhashedstring_p.h
@@ -54,7 +54,6 @@
 #include <QtCore/qglobal.h>
 #include <QtCore/qstring.h>
 #include <private/qv4string_p.h>
-#include <private/qv4scopedvalue_p.h>
 
 #include <private/qflagpointer_p.h>
 
diff --git a/src/qml/qml/qqml.h b/src/qml/qml/qqml.h
index a71d06f7de..8fb710ad9d 100644
--- a/src/qml/qml/qqml.h
+++ b/src/qml/qml/qqml.h
@@ -111,10 +111,11 @@ int qmlRegisterType()
 
         qRegisterNormalizedMetaType<T *>(pointerName.constData()),
         qRegisterNormalizedMetaType<QQmlListProperty<T> >(listName.constData()),
-        0, 0,
+        0,
+        Q_NULLPTR,
         QString(),
 
-        0, 0, 0, 0, &T::staticMetaObject,
+        Q_NULLPTR, 0, 0, Q_NULLPTR, &T::staticMetaObject,
 
         QQmlPrivate::attachedPropertiesFunc<T>(),
         QQmlPrivate::attachedPropertiesMetaObject<T>(),
@@ -123,9 +124,9 @@ int qmlRegisterType()
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueSource>::cast(),
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueInterceptor>::cast(),
 
-        0, 0,
+        Q_NULLPTR, Q_NULLPTR,
 
-        0,
+        Q_NULLPTR,
         0
     };
 
@@ -144,7 +145,8 @@ int qmlRegisterUncreatableType(const char *uri, int versionMajor, int versionMin
 
         qRegisterNormalizedMetaType<T *>(pointerName.constData()),
         qRegisterNormalizedMetaType<QQmlListProperty<T> >(listName.constData()),
-        0, 0,
+        0,
+        Q_NULLPTR,
         reason,
 
         uri, versionMajor, versionMinor, qmlName, &T::staticMetaObject,
@@ -156,9 +158,9 @@ int qmlRegisterUncreatableType(const char *uri, int versionMajor, int versionMin
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueSource>::cast(),
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueInterceptor>::cast(),
 
-        0, 0,
+        Q_NULLPTR, Q_NULLPTR,
 
-        0,
+        Q_NULLPTR,
         0
     };
 
@@ -175,7 +177,8 @@ int qmlRegisterUncreatableType(const char *uri, int versionMajor, int versionMin
 
         qRegisterNormalizedMetaType<T *>(pointerName.constData()),
         qRegisterNormalizedMetaType<QQmlListProperty<T> >(listName.constData()),
-        0, 0,
+        0,
+        Q_NULLPTR,
         reason,
 
         uri, versionMajor, versionMinor, qmlName, &T::staticMetaObject,
@@ -187,9 +190,9 @@ int qmlRegisterUncreatableType(const char *uri, int versionMajor, int versionMin
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueSource>::cast(),
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueInterceptor>::cast(),
 
-        0, 0,
+        Q_NULLPTR, Q_NULLPTR,
 
-        0,
+        Q_NULLPTR,
         metaObjectRevision
     };
 
@@ -213,7 +216,8 @@ int qmlRegisterExtendedUncreatableType(const char *uri, int versionMajor, int ve
 
         qRegisterNormalizedMetaType<T *>(pointerName.constData()),
         qRegisterNormalizedMetaType<QQmlListProperty<T> >(listName.constData()),
-        0, 0,
+        0,
+        Q_NULLPTR,
         reason,
 
         uri, versionMajor, versionMinor, qmlName, &T::staticMetaObject,
@@ -227,7 +231,7 @@ int qmlRegisterExtendedUncreatableType(const char *uri, int versionMajor, int ve
 
         QQmlPrivate::createParent<E>, &E::staticMetaObject,
 
-        0,
+        Q_NULLPTR,
         0
     };
 
@@ -256,9 +260,9 @@ int qmlRegisterType(const char *uri, int versionMajor, int versionMinor, const c
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueSource>::cast(),
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueInterceptor>::cast(),
 
-        0, 0,
+        Q_NULLPTR, Q_NULLPTR,
 
-        0,
+        Q_NULLPTR,
         0
     };
 
@@ -287,9 +291,9 @@ int qmlRegisterType(const char *uri, int versionMajor, int versionMinor, const c
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueSource>::cast(),
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueInterceptor>::cast(),
 
-        0, 0,
+        Q_NULLPTR, Q_NULLPTR,
 
-        0,
+        Q_NULLPTR,
         metaObjectRevision
     };
 
@@ -318,9 +322,9 @@ int qmlRegisterRevision(const char *uri, int versionMajor, int versionMinor)
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueSource>::cast(),
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueInterceptor>::cast(),
 
-        0, 0,
+        Q_NULLPTR, Q_NULLPTR,
 
-        0,
+        Q_NULLPTR,
         metaObjectRevision
     };
 
@@ -338,10 +342,11 @@ int qmlRegisterExtendedType()
 
         qRegisterNormalizedMetaType<T *>(pointerName.constData()),
         qRegisterNormalizedMetaType<QQmlListProperty<T> >(listName.constData()),
-        0, 0,
+        0,
+        Q_NULLPTR,
         QString(),
 
-        0, 0, 0, 0, &T::staticMetaObject,
+        Q_NULLPTR, 0, 0, Q_NULLPTR, &T::staticMetaObject,
 
         QQmlPrivate::attachedPropertiesFunc<T>(),
         QQmlPrivate::attachedPropertiesMetaObject<T>(),
@@ -352,7 +357,7 @@ int qmlRegisterExtendedType()
 
         QQmlPrivate::createParent<E>, &E::staticMetaObject,
 
-        0,
+        Q_NULLPTR,
         0
     };
 
@@ -391,7 +396,7 @@ int qmlRegisterExtendedType(const char *uri, int versionMajor, int versionMinor,
 
         QQmlPrivate::createParent<E>, &E::staticMetaObject,
 
-        0,
+        Q_NULLPTR,
         0
     };
 
@@ -441,7 +446,7 @@ int qmlRegisterCustomType(const char *uri, int versionMajor, int versionMinor,
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueSource>::cast(),
         QQmlPrivate::StaticCastSelector<T,QQmlPropertyValueInterceptor>::cast(),
 
-        0, 0,
+        Q_NULLPTR, Q_NULLPTR,
 
         parser,
         0
@@ -536,7 +541,7 @@ inline int qmlRegisterSingletonType(const char *uri, int versionMajor, int versi
 
         uri, versionMajor, versionMinor, typeName,
 
-        callback, 0, 0, 0, 0
+        callback, Q_NULLPTR, Q_NULLPTR, 0, 0
     };
 
     return QQmlPrivate::qmlregister(QQmlPrivate::SingletonRegistration, &api);
@@ -554,7 +559,7 @@ inline int qmlRegisterSingletonType(const char *uri, int versionMajor, int versi
 
         uri, versionMajor, versionMinor, typeName,
 
-        0, callback, &T::staticMetaObject, qRegisterNormalizedMetaType<T *>(pointerName.constData()), 0
+        Q_NULLPTR, callback, &T::staticMetaObject, qRegisterNormalizedMetaType<T *>(pointerName.constData()), 0
     };
 
     return QQmlPrivate::qmlregister(QQmlPrivate::SingletonRegistration, &api);
diff --git a/src/qml/qml/qqmlaccessors_p.h b/src/qml/qml/qqmlaccessors_p.h
index cae4e2c2ff..55562a5307 100644
--- a/src/qml/qml/qqmlaccessors_p.h
+++ b/src/qml/qml/qqmlaccessors_p.h
@@ -103,7 +103,7 @@ class QQmlNotifier;
     } while (false);
 
 #define QML_PRIVATE_ACCESSOR(clazz, cpptype, name, variable) \
-    static void clazz ## _ ## name ## Read(QObject *o, qintptr, void *rv) \
+    static void clazz ## _ ## name ## Read(QObject *o, void *rv) \
     { \
         clazz ## Private *d = clazz ## Private::get(static_cast<clazz *>(o)); \
         *static_cast<cpptype *>(rv) = d->variable; \
@@ -114,8 +114,8 @@ class QQmlNotifier;
 class QQmlAccessors
 {
 public:
-    void (*read)(QObject *object, qintptr property, void *output);
-    void (*notifier)(QObject *object, qintptr property, QQmlNotifier **notifier);
+    void (*read)(QObject *object, void *output);
+    void (*notifier)(QObject *object, QQmlNotifier **notifier);
 };
 
 namespace QQmlAccessorProperties {
diff --git a/src/qml/qml/qqmlapplicationengine.h b/src/qml/qml/qqmlapplicationengine.h
index 59667a1841..ff7dce5f8b 100644
--- a/src/qml/qml/qqmlapplicationengine.h
+++ b/src/qml/qml/qqmlapplicationengine.h
@@ -53,9 +53,9 @@ class Q_QML_EXPORT QQmlApplicationEngine : public QQmlEngine
 {
     Q_OBJECT
 public:
-    QQmlApplicationEngine(QObject *parent=0);
-    QQmlApplicationEngine(const QUrl &url, QObject *parent=0);
-    QQmlApplicationEngine(const QString &filePath, QObject *parent=0);
+    QQmlApplicationEngine(QObject *parent = Q_NULLPTR);
+    QQmlApplicationEngine(const QUrl &url, QObject *parent = Q_NULLPTR);
+    QQmlApplicationEngine(const QString &filePath, QObject *parent = Q_NULLPTR);
     ~QQmlApplicationEngine();
 
     QList<QObject*> rootObjects();
diff --git a/src/qml/qml/qqmlcomponent.h b/src/qml/qml/qqmlcomponent.h
index 0e226320d6..aefbf20aff 100644
--- a/src/qml/qml/qqmlcomponent.h
+++ b/src/qml/qml/qqmlcomponent.h
@@ -72,12 +72,12 @@ public:
     enum CompilationMode { PreferSynchronous, Asynchronous };
     Q_ENUM(CompilationMode)
 
-    QQmlComponent(QObject *parent = 0);
-    QQmlComponent(QQmlEngine *, QObject *parent=0);
-    QQmlComponent(QQmlEngine *, const QString &fileName, QObject *parent = 0);
-    QQmlComponent(QQmlEngine *, const QString &fileName, CompilationMode mode, QObject *parent = 0);
-    QQmlComponent(QQmlEngine *, const QUrl &url, QObject *parent = 0);
-    QQmlComponent(QQmlEngine *, const QUrl &url, CompilationMode mode, QObject *parent = 0);
+    QQmlComponent(QObject *parent = Q_NULLPTR);
+    QQmlComponent(QQmlEngine *, QObject *parent = Q_NULLPTR);
+    QQmlComponent(QQmlEngine *, const QString &fileName, QObject *parent = Q_NULLPTR);
+    QQmlComponent(QQmlEngine *, const QString &fileName, CompilationMode mode, QObject *parent = Q_NULLPTR);
+    QQmlComponent(QQmlEngine *, const QUrl &url, QObject *parent = Q_NULLPTR);
+    QQmlComponent(QQmlEngine *, const QUrl &url, CompilationMode mode, QObject *parent = Q_NULLPTR);
     virtual ~QQmlComponent();
 
     enum Status { Null, Ready, Loading, Error };
@@ -96,12 +96,12 @@ public:
 
     QUrl url() const;
 
-    virtual QObject *create(QQmlContext *context = 0);
+    virtual QObject *create(QQmlContext *context = Q_NULLPTR);
     virtual QObject *beginCreate(QQmlContext *);
     virtual void completeCreate();
 
-    void create(QQmlIncubator &, QQmlContext *context = 0,
-                QQmlContext *forContext = 0);
+    void create(QQmlIncubator &, QQmlContext *context = Q_NULLPTR,
+                QQmlContext *forContext = Q_NULLPTR);
 
     QQmlContext *creationContext() const;
 
diff --git a/src/qml/qml/qqmlcontext.cpp b/src/qml/qml/qqmlcontext.cpp
index f759f46af5..65a337f4e5 100644
--- a/src/qml/qml/qqmlcontext.cpp
+++ b/src/qml/qml/qqmlcontext.cpp
@@ -95,7 +95,7 @@ QQmlContextPrivate::QQmlContextPrivate()
     by name in the context, as though they were all individually added through calls
     to QQmlContext::setContextProperty().  Changes to the property's values are
     detected through the property's notify signal.  Setting a context object is both
-    faster and easier than manually adding and maintaing context property values.
+    faster and easier than manually adding and maintaining context property values.
 
     The following example has the same effect as the previous one, but it uses a context
     object.
diff --git a/src/qml/qml/qqmlcontext.h b/src/qml/qml/qqmlcontext.h
index c6b5d44f5a..781eac44fc 100644
--- a/src/qml/qml/qqmlcontext.h
+++ b/src/qml/qml/qqmlcontext.h
@@ -62,8 +62,8 @@ class Q_QML_EXPORT QQmlContext : public QObject
     Q_DECLARE_PRIVATE(QQmlContext)
 
 public:
-    QQmlContext(QQmlEngine *parent, QObject *objParent=0);
-    QQmlContext(QQmlContext *parent, QObject *objParent=0);
+    QQmlContext(QQmlEngine *parent, QObject *objParent = Q_NULLPTR);
+    QQmlContext(QQmlContext *parent, QObject *objParent = Q_NULLPTR);
     virtual ~QQmlContext();
 
     bool isValid() const;
diff --git a/src/qml/qml/qqmlcontext_p.h b/src/qml/qml/qqmlcontext_p.h
index 057f4b54c0..48d596418d 100644
--- a/src/qml/qml/qqmlcontext_p.h
+++ b/src/qml/qml/qqmlcontext_p.h
@@ -66,6 +66,7 @@
 #include <private/qflagpointer_p.h>
 #include <private/qqmlguard_p.h>
 
+#include <private/qv4compileddata_p.h>
 #include <private/qv4identifier_p.h>
 
 QT_BEGIN_NAMESPACE
diff --git a/src/qml/qml/qqmlengine.h b/src/qml/qml/qqmlengine.h
index 28bd66047e..132af78f80 100644
--- a/src/qml/qml/qqmlengine.h
+++ b/src/qml/qml/qqmlengine.h
@@ -97,7 +97,7 @@ class Q_QML_EXPORT QQmlEngine : public QJSEngine
     Q_PROPERTY(QString offlineStoragePath READ offlineStoragePath WRITE setOfflineStoragePath)
     Q_OBJECT
 public:
-    QQmlEngine(QObject *p = 0);
+    explicit QQmlEngine(QObject *p = Q_NULLPTR);
     virtual ~QQmlEngine();
 
     QQmlContext *rootContext() const;
diff --git a/src/qml/qml/qqmlengine_p.h b/src/qml/qml/qqmlengine_p.h
index 7258ffe6ed..795a505742 100644
--- a/src/qml/qml/qqmlengine_p.h
+++ b/src/qml/qml/qqmlengine_p.h
@@ -375,7 +375,7 @@ const QQmlEnginePrivate *QQmlEnginePrivate::get(const QQmlEngine *e)
 {
     Q_ASSERT(e);
 
-    return e->d_func();
+    return e ? e->d_func() : nullptr;
 }
 
 QQmlEnginePrivate *QQmlEnginePrivate::get(QQmlContext *c)
diff --git a/src/qml/qml/qqmlexpression.h b/src/qml/qml/qqmlexpression.h
index 0aff4884f9..5239d59c8a 100644
--- a/src/qml/qml/qqmlexpression.h
+++ b/src/qml/qml/qqmlexpression.h
@@ -60,8 +60,8 @@ class Q_QML_EXPORT QQmlExpression : public QObject
     Q_OBJECT
 public:
     QQmlExpression();
-    QQmlExpression(QQmlContext *, QObject *, const QString &, QObject * = 0);
-    explicit QQmlExpression(const QQmlScriptString &, QQmlContext * = 0, QObject * = 0, QObject * = 0);
+    QQmlExpression(QQmlContext *, QObject *, const QString &, QObject * = Q_NULLPTR);
+    explicit QQmlExpression(const QQmlScriptString &, QQmlContext * = Q_NULLPTR, QObject * = Q_NULLPTR, QObject * = Q_NULLPTR);
     virtual ~QQmlExpression();
 
     QQmlEngine *engine() const;
@@ -84,7 +84,7 @@ public:
     void clearError();
     QQmlError error() const;
 
-    QVariant evaluate(bool *valueIsUndefined = 0);
+    QVariant evaluate(bool *valueIsUndefined = Q_NULLPTR);
 
 Q_SIGNALS:
     void valueChanged();
diff --git a/src/qml/qml/qqmlextensionplugin.h b/src/qml/qml/qqmlextensionplugin.h
index d0ee16ac50..de482d0352 100644
--- a/src/qml/qml/qqmlextensionplugin.h
+++ b/src/qml/qml/qqmlextensionplugin.h
@@ -58,7 +58,7 @@ class Q_QML_EXPORT QQmlExtensionPlugin
     Q_INTERFACES(QQmlExtensionInterface)
     Q_INTERFACES(QQmlTypesExtensionInterface)
 public:
-    explicit QQmlExtensionPlugin(QObject *parent = 0);
+    explicit QQmlExtensionPlugin(QObject *parent = Q_NULLPTR);
     ~QQmlExtensionPlugin();
 
     QUrl baseUrl() const;
diff --git a/src/qml/qml/qqmlfileselector.h b/src/qml/qml/qqmlfileselector.h
index 34ba4d7a56..03b951420e 100644
--- a/src/qml/qml/qqmlfileselector.h
+++ b/src/qml/qml/qqmlfileselector.h
@@ -54,7 +54,7 @@ class Q_QML_EXPORT QQmlFileSelector : public QObject
     Q_OBJECT
     Q_DECLARE_PRIVATE(QQmlFileSelector)
 public:
-    QQmlFileSelector(QQmlEngine* engine, QObject* parent=0);
+    explicit QQmlFileSelector(QQmlEngine *engine, QObject *parent = Q_NULLPTR);
     ~QQmlFileSelector();
     QFileSelector *selector() const Q_DECL_NOTHROW;
     void setSelector(QFileSelector *selector);
diff --git a/src/qml/qml/qqmlimport.cpp b/src/qml/qml/qqmlimport.cpp
index 0014ccd3ba..d6c81bcc49 100644
--- a/src/qml/qml/qqmlimport.cpp
+++ b/src/qml/qml/qqmlimport.cpp
@@ -888,6 +888,11 @@ bool QQmlImportsPrivate::populatePluginPairVector(QVector<StaticPluginPair> &res
 }
 #endif
 
+static inline QString msgCannotLoadPlugin(const QString &uri, const QString &why)
+{
+    return QQmlImportDatabase::tr("plugin cannot be loaded for module \"%1\": %2").arg(uri, why);
+}
+
 /*!
 Import an extension defined by a qmldir file.
 
@@ -949,7 +954,7 @@ bool QQmlImportsPrivate::importExtension(const QString &qmldirFilePath,
                         // The reason is that the lower level may add url and line/column numbering information.
                         QQmlError poppedError = errors->takeFirst();
                         QQmlError error;
-                        error.setDescription(QQmlImportDatabase::tr("plugin cannot be loaded for module \"%1\": %2").arg(uri).arg(poppedError.description()));
+                        error.setDescription(msgCannotLoadPlugin(uri, poppedError.description()));
                         error.setUrl(QUrl::fromLocalFile(qmldirFilePath));
                         errors->prepend(error);
                     }
@@ -1020,10 +1025,7 @@ bool QQmlImportsPrivate::importExtension(const QString &qmldirFilePath,
 
     if (errors) {
         QQmlError error;
-        error.setDescription(
-                    QQmlImportDatabase::tr(
-                        "plugin cannot be loaded for module \"%1\": library loading is disabled")
-                    .arg(uri));
+        error.setDescription(msgCannotLoadPlugin(uri, QQmlImportDatabase::tr("library loading is disabled")));
         error.setUrl(QUrl::fromLocalFile(qmldirFilePath));
         errors->prepend(error);
     }
diff --git a/src/qml/qml/qqmljavascriptexpression.cpp b/src/qml/qml/qqmljavascriptexpression.cpp
index aef0916239..15d0a571a5 100644
--- a/src/qml/qml/qqmljavascriptexpression.cpp
+++ b/src/qml/qml/qqmljavascriptexpression.cpp
@@ -298,7 +298,7 @@ void QQmlPropertyCapture::registerQmlDependencies(QV4::ExecutionEngine *engine,
     // Let the caller check and avoid the function call :)
     Q_ASSERT(compiledFunction->hasQmlDependencies());
 
-    QQmlEnginePrivate *ep = engine->qmlEngine() ? QQmlEnginePrivate::get(engine->qmlEngine()) : 0;
+    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine->qmlEngine());
     if (!ep)
         return;
     QQmlPropertyCapture *capture = ep->propertyCapture;
diff --git a/src/qml/qml/qqmllist.h b/src/qml/qml/qqmllist.h
index dd548168c3..e3955deee5 100644
--- a/src/qml/qml/qqmllist.h
+++ b/src/qml/qml/qqmllist.h
@@ -61,15 +61,41 @@ public:
     typedef void (*ClearFunction)(QQmlListProperty<T> *);
 
     QQmlListProperty()
-        : object(0), data(0), append(0), count(0), at(0), clear(0), dummy1(0), dummy2(0) {}
+        : object(Q_NULLPTR),
+          data(Q_NULLPTR),
+          append(Q_NULLPTR),
+          count(Q_NULLPTR),
+          at(Q_NULLPTR),
+          clear(Q_NULLPTR),
+          dummy1(Q_NULLPTR),
+          dummy2(Q_NULLPTR)
+    {}
     QQmlListProperty(QObject *o, QList<T *> &list)
         : object(o), data(&list), append(qlist_append), count(qlist_count), at(qlist_at),
-          clear(qlist_clear), dummy1(0), dummy2(0) {}
+          clear(qlist_clear),
+          dummy1(Q_NULLPTR),
+          dummy2(Q_NULLPTR)
+    {}
     QQmlListProperty(QObject *o, void *d, AppendFunction a, CountFunction c, AtFunction t,
                     ClearFunction r )
-        : object(o), data(d), append(a), count(c), at(t), clear(r), dummy1(0), dummy2(0) {}
+        : object(o),
+          data(d),
+          append(a),
+          count(c),
+          at(t),
+          clear(r),
+          dummy1(Q_NULLPTR),
+          dummy2(Q_NULLPTR)
+    {}
     QQmlListProperty(QObject *o, void *d, CountFunction c, AtFunction t)
-        : object(o), data(d), append(0), count(c), at(t), clear(0), dummy1(0), dummy2(0) {}
+        : object(o),
+          data(d),
+          append(Q_NULLPTR),
+          count(c), at(t),
+          clear(Q_NULLPTR),
+          dummy1(Q_NULLPTR),
+          dummy2(Q_NULLPTR)
+    {}
     bool operator==(const QQmlListProperty &o) const {
         return object == o.object &&
                data == o.data &&
@@ -114,7 +140,7 @@ class Q_QML_EXPORT QQmlListReference
 {
 public:
     QQmlListReference();
-    QQmlListReference(QObject *, const char *property, QQmlEngine * = 0);
+    QQmlListReference(QObject *, const char *property, QQmlEngine * = Q_NULLPTR);
     QQmlListReference(const QQmlListReference &);
     QQmlListReference &operator=(const QQmlListReference &);
     ~QQmlListReference();
diff --git a/src/qml/qml/qqmlobjectcreator.cpp b/src/qml/qml/qqmlobjectcreator.cpp
index 1a7896bde8..29fff04325 100644
--- a/src/qml/qml/qqmlobjectcreator.cpp
+++ b/src/qml/qml/qqmlobjectcreator.cpp
@@ -716,6 +716,8 @@ bool QQmlObjectCreator::setPropertyBinding(const QQmlPropertyData *property, con
             QQmlTypeNameCache::Result res = context->imports->query(stringAt(binding->propertyNameIndex));
             if (res.isValid())
                 attachedType = res.type;
+            else
+                return false;
         }
         const int id = attachedType->attachedPropertiesId(QQmlEnginePrivate::get(engine));
         QObject *qmlObject = qmlAttachedPropertiesObjectById(id, _qobject);
diff --git a/src/qml/qml/qqmlpropertycache.cpp b/src/qml/qml/qqmlpropertycache.cpp
index 357b5ae577..3be52cf461 100644
--- a/src/qml/qml/qqmlpropertycache.cpp
+++ b/src/qml/qml/qqmlpropertycache.cpp
@@ -698,7 +698,6 @@ void QQmlPropertyCache::append(const QMetaObject *metaObject,
         if (accessorProperty) {
             data->flags |= QQmlPropertyData::HasAccessors;
             data->accessors = accessorProperty->accessors;
-            data->accessorData = accessorProperty->data;
         } else if (old) {
             data->markAsOverrideOf(old);
         }
diff --git a/src/qml/qml/qqmlpropertycache_p.h b/src/qml/qml/qqmlpropertycache_p.h
index 0b3573c58c..4ff5ee89f9 100644
--- a/src/qml/qml/qqmlpropertycache_p.h
+++ b/src/qml/qml/qqmlpropertycache_p.h
@@ -209,7 +209,6 @@ public:
         };
         struct { // When HasAccessors
             QQmlAccessors *accessors;
-            qintptr accessorData;
         };
     };
     int coreIndex;
diff --git a/src/qml/types/qqmllistmodelworkeragent_p.h b/src/qml/types/qqmllistmodelworkeragent_p.h
index 0c639b140d..f9872a6ad4 100644
--- a/src/qml/types/qqmllistmodelworkeragent_p.h
+++ b/src/qml/types/qqmllistmodelworkeragent_p.h
@@ -97,7 +97,8 @@ public:
 
         VariantRef &operator=(const VariantRef &o) {
             if (o.a) o.a->addref();
-            if (a) a->release(); a = o.a;
+            if (a) a->release();
+            a = o.a;
             return *this;
         }
 
diff --git a/src/qml/util/qqmlpropertymap.h b/src/qml/util/qqmlpropertymap.h
index ea1561bc60..01048f3662 100644
--- a/src/qml/util/qqmlpropertymap.h
+++ b/src/qml/util/qqmlpropertymap.h
@@ -55,7 +55,7 @@ class Q_QML_EXPORT QQmlPropertyMap : public QObject
 {
     Q_OBJECT
 public:
-    explicit QQmlPropertyMap(QObject *parent = 0);
+    explicit QQmlPropertyMap(QObject *parent = Q_NULLPTR);
     virtual ~QQmlPropertyMap();
 
     QVariant value(const QString &key) const;
diff --git a/src/qmldebug/qqmldebugconnection.cpp b/src/qmldebug/qqmldebugconnection.cpp
index 37b66889cd..35a540bff8 100644
--- a/src/qmldebug/qqmldebugconnection.cpp
+++ b/src/qmldebug/qqmldebugconnection.cpp
@@ -106,7 +106,8 @@ void QQmlDebugConnection::socketConnected()
 {
     Q_D(QQmlDebugConnection);
     QPacket pack(d->currentDataStreamVersion);
-    pack << serverId << 0 << protocolVersion << d->plugins.keys() << d->maximumDataStreamVersion;
+    pack << serverId << 0 << protocolVersion << d->plugins.keys() << d->maximumDataStreamVersion
+         << true; // We accept multiple messages per packet
     d->protocol->send(pack.data());
     d->flush();
 }
@@ -221,9 +222,6 @@ void QQmlDebugConnection::protocolReadyRead()
                 qWarning() << "QQmlDebugConnection: Unknown control message id" << op;
             }
         } else {
-            QByteArray message;
-            pack >> message;
-
             QHash<QString, QQmlDebugClient *>::Iterator iter = d->plugins.find(name);
             if (iter == d->plugins.end()) {
                 // We can get more messages for plugins we have removed because it takes time to
@@ -232,7 +230,12 @@ void QQmlDebugConnection::protocolReadyRead()
                     qWarning() << "QQmlDebugConnection: Message received for missing plugin"
                                << name;
             } else {
-                (*iter)->messageReceived(message);
+                QQmlDebugClient *client = *iter;
+                QByteArray message;
+                while (!pack.atEnd()) {
+                    pack >> message;
+                    client->messageReceived(message);
+                }
             }
         }
     }
diff --git a/src/quick/doc/src/qmltypereference.qdoc b/src/quick/doc/src/qmltypereference.qdoc
index 630e0f58bc..6e6e66e026 100644
--- a/src/quick/doc/src/qmltypereference.qdoc
+++ b/src/quick/doc/src/qmltypereference.qdoc
@@ -26,7 +26,7 @@
 ****************************************************************************/
 
 /*!
-\qmlmodule QtQuick 2.5
+\qmlmodule QtQuick 2.7
 \title Qt Quick QML Types
 \ingroup qmlmodules
 \brief Provides graphical QML types.
@@ -34,11 +34,11 @@
 The \l{Qt Quick} module provides graphical primitive types. These types are only
 available in a QML document if that document imports the \c QtQuick namespace.
 
-The current version of the \c QtQuick module is version 2.5, and thus it may be
+The current version of the \c QtQuick module is version 2.7, and thus it may be
 imported via the following statement:
 
 \qml
-import QtQuick 2.5
+import QtQuick 2.7
 \endqml
 
 Visit the \l {Qt Quick} module documentation for more
diff --git a/src/quick/items/qquickanimatedsprite.cpp b/src/quick/items/qquickanimatedsprite.cpp
index f5df5763bb..c32e9546a5 100644
--- a/src/quick/items/qquickanimatedsprite.cpp
+++ b/src/quick/items/qquickanimatedsprite.cpp
@@ -316,8 +316,6 @@ struct AnimatedSpriteVertices {
 //TODO: Implicitly size element to size of sprite
 QQuickAnimatedSprite::QQuickAnimatedSprite(QQuickItem *parent) :
     QQuickItem(parent)
-    , m_node(0)
-    , m_material(0)
     , m_sprite(new QQuickSprite(this))
     , m_spriteEngine(0)
     , m_curFrame(0)
@@ -331,9 +329,9 @@ QQuickAnimatedSprite::QQuickAnimatedSprite(QQuickItem *parent) :
 {
     setFlag(ItemHasContents);
     connect(this, SIGNAL(widthChanged()),
-            this, SLOT(sizeVertices()));
+            this, SLOT(reset()));
     connect(this, SIGNAL(heightChanged()),
-            this, SLOT(sizeVertices()));
+            this, SLOT(reset()));
 }
 
 bool QQuickAnimatedSprite::isCurrentFrameChangedConnected()
@@ -461,12 +459,9 @@ static QSGGeometry::AttributeSet AnimatedSprite_AttributeSet =
     AnimatedSprite_Attributes
 };
 
-void QQuickAnimatedSprite::sizeVertices()
+void QQuickAnimatedSprite::sizeVertices(QSGGeometryNode *node)
 {
-    if (!m_node)
-        return;
-
-    AnimatedSpriteVertices *p = (AnimatedSpriteVertices *) m_node->geometry()->vertexData();
+    AnimatedSpriteVertices *p = (AnimatedSpriteVertices *) node->geometry()->vertexData();
     p->v1.x = 0;
     p->v1.y = 0;
 
@@ -494,21 +489,21 @@ QSGGeometryNode* QQuickAnimatedSprite::buildNode()
         return 0;
     }
 
-    m_material = new QQuickAnimatedSpriteMaterial();
+    QQuickAnimatedSpriteMaterial *material = new QQuickAnimatedSpriteMaterial();
 
     QImage image = m_spriteEngine->assembledImage(); //Engine prints errors if there are any
     if (image.isNull())
         return 0;
     m_sheetSize = QSizeF(image.size());
-    m_material->texture = window()->createTextureFromImage(image);
+    material->texture = window()->createTextureFromImage(image);
     m_spriteEngine->start(0);
-    m_material->animT = 0;
-    m_material->animX1 = m_spriteEngine->spriteX() / m_sheetSize.width();
-    m_material->animY1 = m_spriteEngine->spriteY() / m_sheetSize.height();
-    m_material->animX2 = m_material->animX1;
-    m_material->animY2 = m_material->animY1;
-    m_material->animW = m_spriteEngine->spriteWidth() / m_sheetSize.width();
-    m_material->animH = m_spriteEngine->spriteHeight() / m_sheetSize.height();
+    material->animT = 0;
+    material->animX1 = m_spriteEngine->spriteX() / m_sheetSize.width();
+    material->animY1 = m_spriteEngine->spriteY() / m_sheetSize.height();
+    material->animX2 = material->animX1;
+    material->animY2 = material->animY1;
+    material->animW = m_spriteEngine->spriteWidth() / m_sheetSize.width();
+    material->animH = m_spriteEngine->spriteHeight() / m_sheetSize.height();
 
     int vCount = 4;
     int iCount = 6;
@@ -517,7 +512,7 @@ QSGGeometryNode* QQuickAnimatedSprite::buildNode()
 
     AnimatedSpriteVertices *p = (AnimatedSpriteVertices *) g->vertexData();
 
-    QRectF texRect = m_material->texture->normalizedTextureSubRect();
+    QRectF texRect = material->texture->normalizedTextureSubRect();
 
     p->v1.tx = texRect.topLeft().x();
     p->v1.ty = texRect.topLeft().y();
@@ -540,51 +535,51 @@ QSGGeometryNode* QQuickAnimatedSprite::buildNode()
     indices[5] = 2;
 
 
-    m_node = new QSGGeometryNode();
-    m_node->setGeometry(g);
-    m_node->setMaterial(m_material);
-    m_node->setFlag(QSGGeometryNode::OwnsMaterial);
-    m_node->setFlag(QSGGeometryNode::OwnsGeometry);
-    sizeVertices();
-    return m_node;
+    QSGGeometryNode *node = new QSGGeometryNode();
+    node->setGeometry(g);
+    node->setMaterial(material);
+    node->setFlag(QSGGeometryNode::OwnsMaterial);
+    node->setFlag(QSGGeometryNode::OwnsGeometry);
+    sizeVertices(node);
+    return node;
 }
 
 void QQuickAnimatedSprite::reset()
 {
     m_pleaseReset = true;
+    update();
 }
 
-QSGNode *QQuickAnimatedSprite::updatePaintNode(QSGNode *, UpdatePaintNodeData *)
+QSGNode *QQuickAnimatedSprite::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *)
 {
     if (m_pleaseReset) {
-        delete m_node;
+        delete oldNode;
 
-        m_node = 0;
-        m_material = 0;
+        oldNode = 0;
         m_pleaseReset = false;
     }
 
-    prepareNextFrame();
+    QSGGeometryNode *node = static_cast<QSGGeometryNode *>(oldNode);
+    if (!node)
+        node = buildNode();
+
+    if (node)
+        prepareNextFrame(node);
 
     if (m_running) {
         if (!m_paused)
             update();
 
-        if (m_node) {
-            m_node->markDirty(QSGNode::DirtyMaterial);
+        if (node) {
+            node->markDirty(QSGNode::DirtyMaterial);
         }
     }
 
-    return m_node;
+    return node;
 }
 
-void QQuickAnimatedSprite::prepareNextFrame()
+void QQuickAnimatedSprite::prepareNextFrame(QSGGeometryNode *node)
 {
-    if (m_node == 0)
-        m_node = buildNode();
-    if (m_node == 0) //error creating node
-        return;
-
     int timeInt = m_timestamp.elapsed() + m_pauseOffset;
     qreal time =  timeInt / 1000.;
 
@@ -700,14 +695,15 @@ void QQuickAnimatedSprite::prepareNextFrame()
         }
     }
 
-    m_material->animX1 = x1;
-    m_material->animY1 = y1;
-    m_material->animX2 = x2;
-    m_material->animY2 = y2;
-    m_material->animW = w;
-    m_material->animH = h;
-    m_material->animT = m_interpolate ? progress : 0.0;
-    m_material->texture->setFiltering(smooth() ? QSGTexture::Linear : QSGTexture::Nearest);
+    QQuickAnimatedSpriteMaterial *material = static_cast<QQuickAnimatedSpriteMaterial *>(node->material());
+    material->animX1 = x1;
+    material->animY1 = y1;
+    material->animX2 = x2;
+    material->animY2 = y2;
+    material->animW = w;
+    material->animH = h;
+    material->animT = m_interpolate ? progress : 0.0;
+    material->texture->setFiltering(smooth() ? QSGTexture::Linear : QSGTexture::Nearest);
 }
 
 QT_END_NAMESPACE
diff --git a/src/quick/items/qquickanimatedsprite_p.h b/src/quick/items/qquickanimatedsprite_p.h
index 6b49d903df..1e5981c1a4 100644
--- a/src/quick/items/qquickanimatedsprite_p.h
+++ b/src/quick/items/qquickanimatedsprite_p.h
@@ -357,19 +357,19 @@ public Q_SLOTS:
 
 private Q_SLOTS:
     void createEngine();
-    void sizeVertices();
+    void sizeVertices(QSGGeometryNode *node);
 
-protected:
+protected Q_SLOTS:
     void reset();
+
+protected:
     void componentComplete() Q_DECL_OVERRIDE;
     QSGNode *updatePaintNode(QSGNode *, UpdatePaintNodeData *) Q_DECL_OVERRIDE;
 private:
     bool isCurrentFrameChangedConnected();
-    void prepareNextFrame();
+    void prepareNextFrame(QSGGeometryNode *node);
     void reloadImage();
     QSGGeometryNode* buildNode();
-    QSGGeometryNode *m_node;
-    QQuickAnimatedSpriteMaterial *m_material;
     QQuickSprite* m_sprite;
     QQuickSpriteEngine* m_spriteEngine;
     QElapsedTimer m_timestamp;
diff --git a/src/quick/items/qquickdrag.cpp b/src/quick/items/qquickdrag.cpp
index 5bfbaf74b2..4aa54b71df 100644
--- a/src/quick/items/qquickdrag.cpp
+++ b/src/quick/items/qquickdrag.cpp
@@ -46,6 +46,7 @@
 #include <QtQuick/private/qquickevents_p_p.h>
 #include <private/qquickitemchangelistener_p.h>
 #include <private/qv8engine_p.h>
+#include <private/qv4scopedvalue_p.h>
 #include <QtCore/qmimedata.h>
 #include <QtQml/qqmlinfo.h>
 #include <QtGui/qdrag.h>
diff --git a/src/quick/items/qquickevents.cpp b/src/quick/items/qquickevents.cpp
index 7706412a5f..5061c19f1e 100644
--- a/src/quick/items/qquickevents.cpp
+++ b/src/quick/items/qquickevents.cpp
@@ -263,6 +263,56 @@ Item {
     \endqml
 */
 
+/*!
+    \qmlproperty int QtQuick::MouseEvent::source
+    \since 5.7
+
+    This property holds the source of the mouse event.
+
+    The mouse event source can be used to distinguish between genuine and
+    artificial mouse events. When using other pointing devices such as
+    touchscreens and graphics tablets, if the application does not make use of
+    the actual touch or tablet events, mouse events may be synthesized by the
+    operating system or by Qt itself.
+
+    The value can be one of:
+
+    \value Qt.MouseEventNotSynthesized The most common value. On platforms where
+    such information is available, this value indicates that the event
+    represents a genuine mouse event from the system.
+
+    \value Qt.MouseEventSynthesizedBySystem Indicates that the mouse event was
+    synthesized from a touch or tablet event by the platform.
+
+    \value Qt.MouseEventSynthesizedByQt Indicates that the mouse event was
+    synthesized from an unhandled touch or tablet event by Qt.
+
+    \value Qt.MouseEventSynthesizedByApplication Indicates that the mouse event
+    was synthesized by the application. This allows distinguishing
+    application-generated mouse events from the ones that are coming from the
+    system or are synthesized by Qt.
+
+    For example, to react only to events which come from an actual mouse:
+    \qml
+    MouseArea {
+        onPressed: if (mouse.source !== Qt.MouseEventNotSynthesized) {
+            mouse.accepted = false
+        }
+
+        onClicked: doSomething()
+    }
+    \endqml
+
+    If the handler for the press event rejects the event, it will be propagated
+    further, and then another Item underneath can handle synthesized events
+    from touchscreens. For example, if a Flickable is used underneath (and the
+    MouseArea is not a child of the Flickable), it can be useful for the
+    MouseArea to handle genuine mouse events in one way, while allowing touch
+    events to fall through to the Flickable underneath, so that the ability to
+    flick on a touchscreen is retained. In that case the ability to drag the
+    Flickable via mouse would be lost, but it does not prevent Flickable from
+    receiving mouse wheel events.
+*/
 
 /*!
     \qmltype WheelEvent
diff --git a/src/quick/items/qquickevents_p_p.h b/src/quick/items/qquickevents_p_p.h
index f0d7769705..b28ab555b0 100644
--- a/src/quick/items/qquickevents_p_p.h
+++ b/src/quick/items/qquickevents_p_p.h
@@ -103,6 +103,7 @@ class Q_QUICK_PRIVATE_EXPORT QQuickMouseEvent : public QObject
     Q_PROPERTY(int button READ button)
     Q_PROPERTY(int buttons READ buttons)
     Q_PROPERTY(int modifiers READ modifiers)
+    Q_PROPERTY(int source READ source REVISION 7)
     Q_PROPERTY(bool wasHeld READ wasHeld)
     Q_PROPERTY(bool isClick READ isClick)
     Q_PROPERTY(bool accepted READ isAccepted WRITE setAccepted)
@@ -111,13 +112,14 @@ public:
     QQuickMouseEvent(qreal x, qreal y, Qt::MouseButton button, Qt::MouseButtons buttons, Qt::KeyboardModifiers modifiers
                   , bool isClick=false, bool wasHeld=false)
         : _x(x), _y(y), _button(button), _buttons(buttons), _modifiers(modifiers)
-          , _wasHeld(wasHeld), _isClick(isClick), _accepted(true) {}
+          , _source(Qt::MouseEventNotSynthesized), _wasHeld(wasHeld), _isClick(isClick), _accepted(true) {}
 
     qreal x() const { return _x; }
     qreal y() const { return _y; }
     int button() const { return _button; }
     int buttons() const { return _buttons; }
     int modifiers() const { return _modifiers; }
+    int source() const { return _source; }
     bool wasHeld() const { return _wasHeld; }
     bool isClick() const { return _isClick; }
 
@@ -125,6 +127,7 @@ public:
     void setX(qreal x) { _x = x; }
     void setY(qreal y) { _y = y; }
     void setPosition(const QPointF &point) { _x = point.x(); _y = point.y(); }
+    void setSource(Qt::MouseEventSource s) { _source = s; }
 
     bool isAccepted() { return _accepted; }
     void setAccepted(bool accepted) { _accepted = accepted; }
@@ -135,6 +138,7 @@ private:
     Qt::MouseButton _button;
     Qt::MouseButtons _buttons;
     Qt::KeyboardModifiers _modifiers;
+    Qt::MouseEventSource _source;
     bool _wasHeld;
     bool _isClick;
     bool _accepted;
diff --git a/src/quick/items/qquickframebufferobject.h b/src/quick/items/qquickframebufferobject.h
index 446cfed22b..13eeb931ad 100644
--- a/src/quick/items/qquickframebufferobject.h
+++ b/src/quick/items/qquickframebufferobject.h
@@ -75,7 +75,7 @@ public:
         void *data;
     };
 
-    QQuickFramebufferObject(QQuickItem *parent = 0);
+    QQuickFramebufferObject(QQuickItem *parent = Q_NULLPTR);
 
     bool textureFollowsItemSize() const;
     void setTextureFollowsItemSize(bool follows);
diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index ca7c5b224c..da89a51f24 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -109,7 +109,7 @@ void debugFocusTree(QQuickItem *item, QQuickItem *scope = 0, int depth = 1)
     }
 }
 
-static void QQuickItem_parentNotifier(QObject *o, qintptr, QQmlNotifier **n)
+static void QQuickItem_parentNotifier(QObject *o, QQmlNotifier **n)
 {
     QQuickItemPrivate *d = QQuickItemPrivate::get(static_cast<QQuickItem *>(o));
     *n = &d->parentNotifier;
diff --git a/src/quick/items/qquickitem.h b/src/quick/items/qquickitem.h
index b33f3d8b6a..c5c17615ee 100644
--- a/src/quick/items/qquickitem.h
+++ b/src/quick/items/qquickitem.h
@@ -59,7 +59,7 @@ class Q_QUICK_EXPORT QQuickTransform : public QObject
 {
     Q_OBJECT
 public:
-    QQuickTransform(QObject *parent = 0);
+    explicit QQuickTransform(QObject *parent = Q_NULLPTR);
     ~QQuickTransform();
 
     void appendToItem(QQuickItem *);
@@ -195,7 +195,7 @@ public:
     };
     Q_ENUM(TransformOrigin)
 
-    QQuickItem(QQuickItem *parent = 0);
+    explicit QQuickItem(QQuickItem *parent = Q_NULLPTR);
     virtual ~QQuickItem();
 
     QQuickWindow *window() const;
@@ -440,7 +440,7 @@ protected:
     virtual void updatePolish();
 
 protected:
-    QQuickItem(QQuickItemPrivate &dd, QQuickItem *parent = 0);
+    QQuickItem(QQuickItemPrivate &dd, QQuickItem *parent = Q_NULLPTR);
 
 private:
     Q_PRIVATE_SLOT(d_func(), void _q_resourceObjectDeleted(QObject *))
diff --git a/src/quick/items/qquickitemgrabresult.h b/src/quick/items/qquickitemgrabresult.h
index 15399010dd..42d71862de 100644
--- a/src/quick/items/qquickitemgrabresult.h
+++ b/src/quick/items/qquickitemgrabresult.h
@@ -79,7 +79,7 @@ private Q_SLOTS:
 private:
     friend class QQuickItem;
 
-    QQuickItemGrabResult(QObject *parent = 0);
+    QQuickItemGrabResult(QObject *parent = Q_NULLPTR);
 };
 
 QT_END_NAMESPACE
diff --git a/src/quick/items/qquickitemsmodule.cpp b/src/quick/items/qquickitemsmodule.cpp
index ce4f81e1dd..23245e4a7b 100644
--- a/src/quick/items/qquickitemsmodule.cpp
+++ b/src/quick/items/qquickitemsmodule.cpp
@@ -285,6 +285,8 @@ static void qt_quickitems_defineModule(const char *uri, int major, int minor)
     qmlRegisterType<QQuickGridView, 7>(uri, 2, 7, "GridView");
     qmlRegisterType<QQuickTextInput, 7>(uri, 2, 7, "TextInput");
     qmlRegisterType<QQuickTextEdit, 7>(uri, 2, 7, "TextEdit");
+
+    qmlRegisterUncreatableType<QQuickMouseEvent, 7>(uri, 2, 7, nullptr, QQuickMouseEvent::tr("MouseEvent is only available within handlers in MouseArea"));
 }
 
 static void initResources()
diff --git a/src/quick/items/qquickitemview.cpp b/src/quick/items/qquickitemview.cpp
index 188b347a20..aff03b7539 100644
--- a/src/quick/items/qquickitemview.cpp
+++ b/src/quick/items/qquickitemview.cpp
@@ -1052,7 +1052,8 @@ QQuickItem *QQuickItemView::itemAt(qreal x, qreal y) const
 void QQuickItemView::forceLayout()
 {
     Q_D(QQuickItemView);
-    d->applyPendingChanges();
+    if (isComponentComplete() && (d->currentChanges.hasPendingChanges() || d->forceLayout))
+        d->layout();
 }
 
 void QQuickItemViewPrivate::applyPendingChanges()
diff --git a/src/quick/items/qquickmousearea.cpp b/src/quick/items/qquickmousearea.cpp
index 42de98eff7..920a86881b 100644
--- a/src/quick/items/qquickmousearea.cpp
+++ b/src/quick/items/qquickmousearea.cpp
@@ -685,7 +685,7 @@ void QQuickMouseArea::mousePressEvent(QMouseEvent *event)
         d->startScene = event->windowPos();
         d->pressAndHoldTimer.start(QGuiApplication::styleHints()->mousePressAndHoldInterval(), this);
         setKeepMouseGrab(d->stealMouse);
-        event->setAccepted(setPressed(event->button(), true));
+        event->setAccepted(setPressed(event->button(), true, event->source()));
     }
 }
 
@@ -762,6 +762,7 @@ void QQuickMouseArea::mouseMoveEvent(QMouseEvent *event)
 #endif
 
     QQuickMouseEvent me(d->lastPos.x(), d->lastPos.y(), d->lastButton, d->lastButtons, d->lastModifiers, false, d->longPress);
+    me.setSource(event->source());
     emit mouseXChanged(&me);
     me.setPosition(d->lastPos);
     emit mouseYChanged(&me);
@@ -777,7 +778,7 @@ void QQuickMouseArea::mouseReleaseEvent(QMouseEvent *event)
         QQuickItem::mouseReleaseEvent(event);
     } else {
         d->saveEvent(event);
-        setPressed(event->button(), false);
+        setPressed(event->button(), false, event->source());
         if (!d->pressed) {
             // no other buttons are pressed
 #ifndef QT_NO_DRAGANDDROP
@@ -802,6 +803,7 @@ void QQuickMouseArea::mouseDoubleClickEvent(QMouseEvent *event)
     if (d->enabled) {
         d->saveEvent(event);
         QQuickMouseEvent me(d->lastPos.x(), d->lastPos.y(), d->lastButton, d->lastButtons, d->lastModifiers, true, false);
+        me.setSource(event->source());
         me.setAccepted(d->isDoubleClickConnected());
         emit this->doubleClicked(&me);
         if (!me.isAccepted())
@@ -996,6 +998,7 @@ void QQuickMouseArea::timerEvent(QTimerEvent *event)
         if (d->pressed && dragged == false && d->hovered == true) {
             d->longPress = true;
             QQuickMouseEvent me(d->lastPos.x(), d->lastPos.y(), d->lastButton, d->lastButtons, d->lastModifiers, false, d->longPress);
+            me.setSource(Qt::MouseEventSynthesizedByQt);
             me.setAccepted(d->isPressAndHoldConnected());
             emit pressAndHold(&me);
             if (!me.isAccepted())
@@ -1158,7 +1161,7 @@ void QQuickMouseArea::setAcceptedButtons(Qt::MouseButtons buttons)
     }
 }
 
-bool QQuickMouseArea::setPressed(Qt::MouseButton button, bool p)
+bool QQuickMouseArea::setPressed(Qt::MouseButton button, bool p, Qt::MouseEventSource source)
 {
     Q_D(QQuickMouseArea);
 
@@ -1173,6 +1176,7 @@ bool QQuickMouseArea::setPressed(Qt::MouseButton button, bool p)
 
     if (wasPressed != p) {
         QQuickMouseEvent me(d->lastPos.x(), d->lastPos.y(), d->lastButton, d->lastButtons, d->lastModifiers, isclick, d->longPress);
+        me.setSource(source);
         if (p) {
             d->pressed |= button;
             if (!d->doubleClick)
diff --git a/src/quick/items/qquickmousearea_p.h b/src/quick/items/qquickmousearea_p.h
index ae3e3b1e5a..5cd86541d4 100644
--- a/src/quick/items/qquickmousearea_p.h
+++ b/src/quick/items/qquickmousearea_p.h
@@ -155,7 +155,7 @@ Q_SIGNALS:
 
 protected:
     void setHovered(bool);
-    bool setPressed(Qt::MouseButton button, bool);
+    bool setPressed(Qt::MouseButton button, bool p, Qt::MouseEventSource source);
     bool sendMouseEvent(QMouseEvent *event);
 
     void mousePressEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
diff --git a/src/quick/items/qquickpainteditem.h b/src/quick/items/qquickpainteditem.h
index 1e384a45e3..f9e3c91a42 100644
--- a/src/quick/items/qquickpainteditem.h
+++ b/src/quick/items/qquickpainteditem.h
@@ -57,7 +57,7 @@ class Q_QUICK_EXPORT QQuickPaintedItem : public QQuickItem
     Q_PROPERTY(QSize textureSize READ textureSize WRITE setTextureSize NOTIFY textureSizeChanged)
 
 public:
-    QQuickPaintedItem(QQuickItem *parent = 0);
+    explicit QQuickPaintedItem(QQuickItem *parent = Q_NULLPTR);
     virtual ~QQuickPaintedItem();
 
     enum RenderTarget {
@@ -118,7 +118,7 @@ Q_SIGNALS:
     void textureSizeChanged();
 
 protected:
-    QQuickPaintedItem(QQuickPaintedItemPrivate &dd, QQuickItem *parent = 0);
+    QQuickPaintedItem(QQuickPaintedItemPrivate &dd, QQuickItem *parent = Q_NULLPTR);
     QSGNode *updatePaintNode(QSGNode *, UpdatePaintNodeData *) Q_DECL_OVERRIDE;
     void releaseResources() Q_DECL_OVERRIDE;
 
diff --git a/src/quick/items/qquickrendercontrol.cpp b/src/quick/items/qquickrendercontrol.cpp
index 285a394cee..e36df53d38 100644
--- a/src/quick/items/qquickrendercontrol.cpp
+++ b/src/quick/items/qquickrendercontrol.cpp
@@ -54,6 +54,8 @@
 #include <QtQuick/private/qquickwindow_p.h>
 #include <QtCore/private/qobject_p.h>
 
+#include <private/qquickshadereffectnode_p.h>
+
 QT_BEGIN_NAMESPACE
 
 extern Q_GUI_EXPORT QImage qt_gl_read_framebuffer(const QSize &size, bool alpha_format, bool include_alpha);
@@ -181,6 +183,8 @@ void QQuickRenderControlPrivate::windowDestroyed()
         delete QQuickWindowPrivate::get(window)->animationController;
         QQuickWindowPrivate::get(window)->animationController = 0;
 
+        QQuickShaderEffectMaterial::cleanupMaterialCache();
+
         window = 0;
     }
 }
diff --git a/src/quick/items/qquickrendercontrol.h b/src/quick/items/qquickrendercontrol.h
index c5691b1329..31ea176cc1 100644
--- a/src/quick/items/qquickrendercontrol.h
+++ b/src/quick/items/qquickrendercontrol.h
@@ -55,7 +55,7 @@ class Q_QUICK_EXPORT QQuickRenderControl : public QObject
     Q_OBJECT
 
 public:
-    QQuickRenderControl(QObject *parent = 0);
+    explicit QQuickRenderControl(QObject *parent = Q_NULLPTR);
     ~QQuickRenderControl();
 
     void prepareThread(QThread *targetThread);
@@ -68,8 +68,8 @@ public:
 
     QImage grab();
 
-    static QWindow *renderWindowFor(QQuickWindow *win, QPoint *offset = 0);
-    virtual QWindow *renderWindow(QPoint *offset) { Q_UNUSED(offset); return 0; }
+    static QWindow *renderWindowFor(QQuickWindow *win, QPoint *offset = Q_NULLPTR);
+    virtual QWindow *renderWindow(QPoint *offset) { Q_UNUSED(offset); return Q_NULLPTR; }
 
 Q_SIGNALS:
     void renderRequested();
diff --git a/src/quick/items/qquickscalegrid_p_p.h b/src/quick/items/qquickscalegrid_p_p.h
index 8064a31377..a424002dfb 100644
--- a/src/quick/items/qquickscalegrid_p_p.h
+++ b/src/quick/items/qquickscalegrid_p_p.h
@@ -61,7 +61,7 @@
 
 QT_BEGIN_NAMESPACE
 
-class QQuickScaleGrid : public QObject
+class Q_AUTOTEST_EXPORT QQuickScaleGrid : public QObject
 {
     Q_OBJECT
 
diff --git a/src/quick/items/qquickshadereffect.cpp b/src/quick/items/qquickshadereffect.cpp
index 05900bc12b..0cfb85db97 100644
--- a/src/quick/items/qquickshadereffect.cpp
+++ b/src/quick/items/qquickshadereffect.cpp
@@ -958,6 +958,12 @@ void QQuickShaderEffect::updateGeometry()
     update();
 }
 
+void QQuickShaderEffect::updateGeometryIfAtlased()
+{
+    if (m_supportsAtlasTextures)
+        updateGeometry();
+}
+
 void QQuickShaderEffect::updateLogAndStatus(const QString &log, int status)
 {
     m_log = parseLog() + log;
@@ -1006,6 +1012,8 @@ QSGNode *QQuickShaderEffect::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeDa
         m_dirtyUniforms = true;
         m_dirtyGeometry = true;
         connect(node, SIGNAL(logAndStatusChanged(QString,int)), this, SLOT(updateLogAndStatus(QString,int)));
+        connect(node, &QQuickShaderEffectNode::dirtyTexture,
+                this, &QQuickShaderEffect::updateGeometryIfAtlased);
     }
 
     QQuickShaderEffectMaterial *material = static_cast<QQuickShaderEffectMaterial *>(node->material());
diff --git a/src/quick/items/qquickshadereffect_p.h b/src/quick/items/qquickshadereffect_p.h
index 23557e52fa..fb266d4c44 100644
--- a/src/quick/items/qquickshadereffect_p.h
+++ b/src/quick/items/qquickshadereffect_p.h
@@ -173,6 +173,7 @@ protected:
 
 private Q_SLOTS:
     void updateGeometry();
+    void updateGeometryIfAtlased();
     void updateLogAndStatus(const QString &log, int status);
     void sourceDestroyed(QObject *object);
     void propertyChanged(int mappedId);
diff --git a/src/quick/items/qquickshadereffectnode.cpp b/src/quick/items/qquickshadereffectnode.cpp
index 8040bbe754..66154fac6d 100644
--- a/src/quick/items/qquickshadereffectnode.cpp
+++ b/src/quick/items/qquickshadereffectnode.cpp
@@ -497,6 +497,7 @@ QQuickShaderEffectNode::~QQuickShaderEffectNode()
 void QQuickShaderEffectNode::markDirtyTexture()
 {
     markDirty(DirtyMaterial);
+    Q_EMIT dirtyTexture();
 }
 
 void QQuickShaderEffectNode::textureProviderDestroyed(QObject *object)
diff --git a/src/quick/items/qquickshadereffectnode_p.h b/src/quick/items/qquickshadereffectnode_p.h
index 570a0c3213..cc016d13a7 100644
--- a/src/quick/items/qquickshadereffectnode_p.h
+++ b/src/quick/items/qquickshadereffectnode_p.h
@@ -148,6 +148,7 @@ public:
 
 Q_SIGNALS:
     void logAndStatusChanged(const QString &, int status);
+    void dirtyTexture();
 
 private Q_SLOTS:
     void markDirtyTexture();
diff --git a/src/quick/items/qquickshadereffectsource.cpp b/src/quick/items/qquickshadereffectsource.cpp
index cd2e2c1cb6..a8cf6155a0 100644
--- a/src/quick/items/qquickshadereffectsource.cpp
+++ b/src/quick/items/qquickshadereffectsource.cpp
@@ -269,6 +269,8 @@ QSGTextureProvider *QQuickShaderEffectSource::textureProvider() const
     Modifying this property makes most sense when the item is used as a
     source texture of a \l ShaderEffect.
 
+    The default value is \c{ShaderEffectSource.ClampToEdge}.
+
     \list
     \li ShaderEffectSource.ClampToEdge - GL_CLAMP_TO_EDGE both horizontally and vertically
     \li ShaderEffectSource.RepeatHorizontally - GL_REPEAT horizontally, GL_CLAMP_TO_EDGE vertically
diff --git a/src/quick/items/qquicksprite.cpp b/src/quick/items/qquicksprite.cpp
index 6429c0d668..63d3180842 100644
--- a/src/quick/items/qquicksprite.cpp
+++ b/src/quick/items/qquicksprite.cpp
@@ -224,6 +224,11 @@ QQuickSprite::QQuickSprite(QObject *parent)
 {
 }
 
+/*! \internal */
+QQuickSprite::~QQuickSprite()
+{
+}
+
 int QQuickSprite::variedDuration() const //Deals with precedence when multiple durations are set
 {
     if (m_frameSync)
diff --git a/src/quick/items/qquicksprite_p.h b/src/quick/items/qquicksprite_p.h
index 3a91b3374a..1b8c8cee84 100644
--- a/src/quick/items/qquicksprite_p.h
+++ b/src/quick/items/qquicksprite_p.h
@@ -61,7 +61,8 @@
 
 QT_BEGIN_NAMESPACE
 
-class QQuickSprite : public QQuickStochasticState
+// exported, since it's used in QtQuickParticles
+class Q_QUICK_EXPORT QQuickSprite : public QQuickStochasticState
 {
     Q_OBJECT
     Q_PROPERTY(QUrl source READ source WRITE setSource NOTIFY sourceChanged)
@@ -84,6 +85,7 @@ class QQuickSprite : public QQuickStochasticState
 
 public:
     explicit QQuickSprite(QObject *parent = 0);
+    ~QQuickSprite();
 
     QUrl source() const
     {
diff --git a/src/quick/items/qquicktextedit.cpp b/src/quick/items/qquicktextedit.cpp
index d2b719e8ef..a44f549b37 100644
--- a/src/quick/items/qquicktextedit.cpp
+++ b/src/quick/items/qquicktextedit.cpp
@@ -1567,8 +1567,7 @@ void QQuickTextEdit::setReadOnly(bool r)
     if (!r)
         flags = flags | Qt::TextEditable;
     d->control->setTextInteractionFlags(flags);
-    if (!r)
-        d->control->moveCursor(QTextCursor::End);
+    d->control->moveCursor(QTextCursor::End);
 
 #ifndef QT_NO_IM
     updateInputMethod(Qt::ImEnabled);
diff --git a/src/quick/items/qquicktextinput.cpp b/src/quick/items/qquicktextinput.cpp
index 3b1901e075..fec9beedf6 100644
--- a/src/quick/items/qquicktextinput.cpp
+++ b/src/quick/items/qquicktextinput.cpp
@@ -43,7 +43,7 @@
 #include "qquicktextutil_p.h"
 
 #include <private/qqmlglobal_p.h>
-
+#include <private/qv4scopedvalue_p.h>
 
 #include <QtCore/qcoreapplication.h>
 #include <QtCore/qmimedata.h>
@@ -711,8 +711,7 @@ void QQuickTextInput::setReadOnly(bool ro)
     setFlag(QQuickItem::ItemAcceptsInputMethod, !ro);
 #endif
     d->m_readOnly = ro;
-    if (!ro)
-        d->setCursorPosition(d->end());
+    d->setCursorPosition(d->end());
 #ifndef QT_NO_IM
     updateInputMethod(Qt::ImEnabled);
 #endif
@@ -1970,11 +1969,15 @@ bool QQuickTextInput::isRightToLeft(int start, int end)
     \qmlmethod QtQuick::TextInput::cut()
 
     Moves the currently selected text to the system clipboard.
+
+    \note If the echo mode is set to a mode other than Normal then cut
+    will not work.  This is to prevent using cut as a method of bypassing
+    password features of the line control.
 */
 void QQuickTextInput::cut()
 {
     Q_D(QQuickTextInput);
-    if (!d->m_readOnly) {
+    if (!d->m_readOnly && d->m_echoMode == QQuickTextInput::Normal) {
         d->copy();
         d->del();
     }
@@ -1984,6 +1987,10 @@ void QQuickTextInput::cut()
     \qmlmethod QtQuick::TextInput::copy()
 
     Copies the currently selected text to the system clipboard.
+
+    \note If the echo mode is set to a mode other than Normal then copy
+    will not work.  This is to prevent using copy as a method of bypassing
+    password features of the line control.
 */
 void QQuickTextInput::copy()
 {
@@ -4363,10 +4370,7 @@ void QQuickTextInputPrivate::processKeyEvent(QKeyEvent* event)
         }
     }
     else if (event == QKeySequence::Cut) {
-        if (!m_readOnly) {
-            copy();
-            del();
-        }
+        q->cut();
     }
     else if (event == QKeySequence::DeleteEndOfLine) {
         if (!m_readOnly)
diff --git a/src/quick/items/qquickview.h b/src/quick/items/qquickview.h
index 29ce5b4935..1fcc34e3a1 100644
--- a/src/quick/items/qquickview.h
+++ b/src/quick/items/qquickview.h
@@ -60,9 +60,9 @@ class Q_QUICK_EXPORT QQuickView : public QQuickWindow
     Q_PROPERTY(Status status READ status NOTIFY statusChanged)
     Q_PROPERTY(QUrl source READ source WRITE setSource DESIGNABLE true)
 public:
-    explicit QQuickView(QWindow *parent = 0);
+    explicit QQuickView(QWindow *parent = Q_NULLPTR);
     QQuickView(QQmlEngine* engine, QWindow *parent);
-    QQuickView(const QUrl &source, QWindow *parent = 0);
+    explicit QQuickView(const QUrl &source, QWindow *parent = Q_NULLPTR);
     virtual ~QQuickView();
 
     QUrl source() const;
diff --git a/src/quick/items/qquickwindow.cpp b/src/quick/items/qquickwindow.cpp
index 70f60b9ae3..cae32dfa49 100644
--- a/src/quick/items/qquickwindow.cpp
+++ b/src/quick/items/qquickwindow.cpp
@@ -1820,7 +1820,7 @@ bool QQuickWindowPrivate::deliverWheelEvent(QQuickItem *item, QWheelEvent *event
 
     if (item->contains(p)) {
         QWheelEvent wheel(p, p, event->pixelDelta(), event->angleDelta(), event->delta(),
-                          event->orientation(), event->buttons(), event->modifiers(), event->phase(), event->source());
+                          event->orientation(), event->buttons(), event->modifiers(), event->phase(), event->source(), event->inverted());
         wheel.accept();
         q->sendEvent(item, &wheel);
         if (wheel.isAccepted()) {
diff --git a/src/quick/items/qquickwindow.h b/src/quick/items/qquickwindow.h
index e04a4a1ce2..1024147bb4 100644
--- a/src/quick/items/qquickwindow.h
+++ b/src/quick/items/qquickwindow.h
@@ -95,7 +95,7 @@ public:
     };
     Q_ENUM(SceneGraphError)
 
-    QQuickWindow(QWindow *parent = 0);
+    explicit QQuickWindow(QWindow *parent = Q_NULLPTR);
     explicit QQuickWindow(QQuickRenderControl *renderControl);
 
     virtual ~QQuickWindow();
@@ -129,7 +129,7 @@ public:
     // Scene graph specific functions
     QSGTexture *createTextureFromImage(const QImage &image) const;
     QSGTexture *createTextureFromImage(const QImage &image, CreateTextureOptions options) const;
-    QSGTexture *createTextureFromId(uint id, const QSize &size, CreateTextureOptions options = CreateTextureOption(0)) const;
+    QSGTexture *createTextureFromId(uint id, const QSize &size, CreateTextureOptions options = CreateTextureOption()) const;
 
     void setClearBeforeRendering(bool enabled);
     bool clearBeforeRendering() const;
@@ -176,7 +176,7 @@ public Q_SLOTS:
     void releaseResources();
 
 protected:
-    QQuickWindow(QQuickWindowPrivate &dd, QWindow *parent = 0);
+    QQuickWindow(QQuickWindowPrivate &dd, QWindow *parent = Q_NULLPTR);
 
     void exposeEvent(QExposeEvent *) Q_DECL_OVERRIDE;
     void resizeEvent(QResizeEvent *) Q_DECL_OVERRIDE;
diff --git a/src/quick/scenegraph/coreapi/qsgabstractrenderer.h b/src/quick/scenegraph/coreapi/qsgabstractrenderer.h
index e02fb819fe..d0a22c8c10 100644
--- a/src/quick/scenegraph/coreapi/qsgabstractrenderer.h
+++ b/src/quick/scenegraph/coreapi/qsgabstractrenderer.h
@@ -86,7 +86,7 @@ Q_SIGNALS:
     void sceneGraphChanged();
 
 protected:
-    QSGAbstractRenderer(QObject *parent = 0);
+    explicit QSGAbstractRenderer(QObject *parent = Q_NULLPTR);
     virtual void nodeChanged(QSGNode *node, QSGNode::DirtyState state) = 0;
 
 private:
diff --git a/src/quick/scenegraph/coreapi/qsgnode.h b/src/quick/scenegraph/coreapi/qsgnode.h
index d294e6f3ca..9d14ae04df 100644
--- a/src/quick/scenegraph/coreapi/qsgnode.h
+++ b/src/quick/scenegraph/coreapi/qsgnode.h
@@ -151,7 +151,7 @@ public:
 
     QT_DEPRECATED void clearDirty() { }
     void markDirty(DirtyState bits);
-    QT_DEPRECATED DirtyState dirtyState() const { return 0; }
+    QT_DEPRECATED DirtyState dirtyState() const { return Q_NULLPTR; }
 
     virtual bool isSubtreeBlocked() const;
 
diff --git a/src/quick/scenegraph/util/qsgatlastexture.cpp b/src/quick/scenegraph/util/qsgatlastexture.cpp
index 57468e5799..68dc813933 100644
--- a/src/quick/scenegraph/util/qsgatlastexture.cpp
+++ b/src/quick/scenegraph/util/qsgatlastexture.cpp
@@ -137,7 +137,7 @@ Atlas::Atlas(const QSize &size)
     if (QOpenGLContext::currentContext()->isOpenGLES()) {
 #endif
 
-#if defined(Q_OS_ANDROID) && !defined(Q_OS_ANDROID_NO_SDK)
+#if defined(Q_OS_ANDROID)
     QString *deviceName =
             static_cast<QString *>(QGuiApplication::platformNativeInterface()->nativeResourceForIntegration("AndroidDeviceName"));
     static bool wrongfullyReportsBgra8888Support = deviceName != 0
diff --git a/src/quick/scenegraph/util/qsgengine.h b/src/quick/scenegraph/util/qsgengine.h
index beeb8a543f..89af71fb47 100644
--- a/src/quick/scenegraph/util/qsgengine.h
+++ b/src/quick/scenegraph/util/qsgengine.h
@@ -63,15 +63,15 @@ public:
     };
     Q_DECLARE_FLAGS(CreateTextureOptions, CreateTextureOption)
 
-    QSGEngine(QObject *parent = 0);
+    explicit QSGEngine(QObject *parent = Q_NULLPTR);
     ~QSGEngine();
 
     void initialize(QOpenGLContext *context);
     void invalidate();
 
     QSGAbstractRenderer *createRenderer() const;
-    QSGTexture *createTextureFromImage(const QImage &image, CreateTextureOptions options = CreateTextureOption(0)) const;
-    QSGTexture *createTextureFromId(uint id, const QSize &size, CreateTextureOptions options = CreateTextureOption(0)) const;
+    QSGTexture *createTextureFromImage(const QImage &image, CreateTextureOptions options = CreateTextureOption()) const;
+    QSGTexture *createTextureFromId(uint id, const QSize &size, CreateTextureOptions options = CreateTextureOption()) const;
 };
 
 QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/util/qsgtexture.cpp b/src/quick/scenegraph/util/qsgtexture.cpp
index 74390334c4..9b9c77dce4 100644
--- a/src/quick/scenegraph/util/qsgtexture.cpp
+++ b/src/quick/scenegraph/util/qsgtexture.cpp
@@ -716,7 +716,7 @@ void QSGPlainTexture::bind()
     GLenum externalFormat = GL_RGBA;
     GLenum internalFormat = GL_RGBA;
 
-#if defined(Q_OS_ANDROID) && !defined(Q_OS_ANDROID_NO_SDK)
+#if defined(Q_OS_ANDROID)
     QString *deviceName =
             static_cast<QString *>(QGuiApplication::platformNativeInterface()->nativeResourceForIntegration("AndroidDeviceName"));
     static bool wrongfullyReportsBgra8888Support = deviceName != 0
diff --git a/src/quick/util/qquickimageprovider.h b/src/quick/util/qquickimageprovider.h
index 0813711e48..d4719a7f5b 100644
--- a/src/quick/util/qquickimageprovider.h
+++ b/src/quick/util/qquickimageprovider.h
@@ -87,7 +87,7 @@ Q_SIGNALS:
 class Q_QUICK_EXPORT QQuickImageProvider : public QQmlImageProviderBase
 {
 public:
-    QQuickImageProvider(ImageType type, Flags flags = 0);
+    QQuickImageProvider(ImageType type, Flags flags = Flags());
     virtual ~QQuickImageProvider();
 
     ImageType imageType() const;
diff --git a/src/quick/util/qquickprofiler.cpp b/src/quick/util/qquickprofiler.cpp
index dc72b5f287..f8d090cc2c 100644
--- a/src/quick/util/qquickprofiler.cpp
+++ b/src/quick/util/qquickprofiler.cpp
@@ -99,22 +99,22 @@ QQuickProfiler::~QQuickProfiler()
 void QQuickProfiler::startProfilingImpl(quint64 features)
 {
     QMutexLocker lock(&m_dataMutex);
-    m_data.clear();
     featuresEnabled = features;
 }
 
 void QQuickProfiler::stopProfilingImpl()
 {
-    {
-        QMutexLocker lock(&m_dataMutex);
-        featuresEnabled = 0;
-    }
+    QMutexLocker lock(&m_dataMutex);
+    featuresEnabled = 0;
     emit dataReady(m_data);
+    m_data.clear();
 }
 
 void QQuickProfiler::reportDataImpl()
 {
+    QMutexLocker lock(&m_dataMutex);
     emit dataReady(m_data);
+    m_data.clear();
 }
 
 void QQuickProfiler::setTimer(const QElapsedTimer &t)
diff --git a/src/quick/util/qquickpropertychanges.cpp b/src/quick/util/qquickpropertychanges.cpp
index 2ee635d71a..0119aecb7e 100644
--- a/src/quick/util/qquickpropertychanges.cpp
+++ b/src/quick/util/qquickpropertychanges.cpp
@@ -61,10 +61,9 @@ QT_BEGIN_NAMESPACE
 
 /*!
     \qmltype PropertyChanges
-    \instantiates QQuickPropertyChanges
     \inqmlmodule QtQuick
     \ingroup qtquick-states
-    \brief Describes new property bindings or values for a state
+    \brief Describes new property bindings or values for a state.
 
     PropertyChanges is used to define the property values or bindings in a
     \l State. This enables an item's property values to be changed when it
diff --git a/src/quickwidgets/qquickwidget.cpp b/src/quickwidgets/qquickwidget.cpp
index b5dd3026a9..3bce7827bc 100644
--- a/src/quickwidgets/qquickwidget.cpp
+++ b/src/quickwidgets/qquickwidget.cpp
@@ -986,7 +986,9 @@ QSize QQuickWidget::initialSize() const
 }
 
 /*!
-  Returns the view's root \l {QQuickItem} {item}.
+  Returns the view's root \l {QQuickItem} {item}. Can be null
+  when setContents/setSource has not been called, if they were called with
+  broken QtQuick code or while the QtQuick contents are being created.
  */
 QQuickItem *QQuickWidget::rootObject() const
 {
diff --git a/src/quickwidgets/qquickwidget.h b/src/quickwidgets/qquickwidget.h
index 688cafd475..0732c506bb 100644
--- a/src/quickwidgets/qquickwidget.h
+++ b/src/quickwidgets/qquickwidget.h
@@ -64,9 +64,9 @@ class Q_QUICKWIDGETS_EXPORT QQuickWidget : public QWidget
     Q_PROPERTY(QUrl source READ source WRITE setSource DESIGNABLE true)
 
 public:
-    explicit QQuickWidget(QWidget *parent = 0);
+    explicit QQuickWidget(QWidget *parent = Q_NULLPTR);
     QQuickWidget(QQmlEngine* engine, QWidget *parent);
-    QQuickWidget(const QUrl &source, QWidget *parent = 0);
+    explicit QQuickWidget(const QUrl &source, QWidget *parent = Q_NULLPTR);
     virtual ~QQuickWidget();
 
     QUrl source() const;