Abstract expression and binding APIs

By splitting the interface through which the system interacts with bindings
away from a specific implementation, we can introduce highly specialized
implementations for specific optimizations.

This commit also includes a sample optimization for object properties being
assigned directly from a local id.

28 files changed, 505 insertions, 142 deletions

diff --git a/src/declarative/qml/qml.pri b/src/declarative/qml/qml.pri
index 75e5692..575876f 100644
--- a/src/declarative/qml/qml.pri
+++ b/src/declarative/qml/qml.pri
@@ -29,7 +29,8 @@ SOURCES += qml/qmlparser.cpp \
     qml/qmlenginedebug.cpp \
     qml/qmlrewrite.cpp \
     qml/qmlbasicscript.cpp \
-    qml/qmlvaluetype.cpp
+    qml/qmlvaluetype.cpp \
+    qml/qmlbindingoptimizations.cpp
 
 HEADERS += qml/qmlparser_p.h \
     qml/qmlinstruction_p.h \
@@ -75,7 +76,8 @@ HEADERS += qml/qmlparser_p.h \
     qml/qmlenginedebug_p.h \
     qml/qmlrewrite_p.h \
     qml/qpodvector_p.h \
-    qml/qmlvaluetype_p.h
+    qml/qmlvaluetype_p.h \
+    qml/qmlbindingoptimizations_p.h
 
 # for qtscript debugger
 contains(QT_CONFIG, scripttools):QT += scripttools
diff --git a/src/declarative/qml/qmlbasicscript.cpp b/src/declarative/qml/qmlbasicscript.cpp
index 21860a5..8993845 100644
--- a/src/declarative/qml/qmlbasicscript.cpp
+++ b/src/declarative/qml/qmlbasicscript.cpp
@@ -697,6 +697,23 @@ QVariant QmlBasicScript::run(QmlContext *context, QObject *me)
         return stack.top();
 }
 
+bool QmlBasicScript::isSingleIdFetch() const
+{
+    if (!isValid())
+        return false;
+
+    return d->instructionCount == 1 && 
+           d->instructions()[0].type == ScriptInstruction::LoadIdObject;
+}
+
+int QmlBasicScript::singleIdFetchIndex() const
+{
+    if (!isSingleIdFetch())
+        return -1;
+
+    return d->instructions()[0].fetch.idx;
+}
+
 /*!
     Return a pointer to the script's compile data, or null if there is no data.
  */
diff --git a/src/declarative/qml/qmlbasicscript_p.h b/src/declarative/qml/qmlbasicscript_p.h
index 92d58f9..d096746 100644
--- a/src/declarative/qml/qmlbasicscript_p.h
+++ b/src/declarative/qml/qmlbasicscript_p.h
@@ -98,6 +98,9 @@ public:
 
     QVariant run(QmlContext *, QObject *);
 
+    bool isSingleIdFetch() const;
+    int singleIdFetchIndex() const;
+
 private:
     int flags;
     QmlBasicScriptPrivate *d;
diff --git a/src/declarative/qml/qmlbinding.cpp b/src/declarative/qml/qmlbinding.cpp
index 41cef49..7c5b366 100644
--- a/src/declarative/qml/qmlbinding.cpp
+++ b/src/declarative/qml/qmlbinding.cpp
@@ -47,6 +47,8 @@
 #include <QVariant>
 #include <private/qfxperf_p.h>
 #include <QtCore/qdebug.h>
+#include <private/qmlcontext_p.h>
+#include <private/qmldeclarativedata_p.h>
 
 Q_DECLARE_METATYPE(QList<QObject *>);
 
@@ -55,7 +57,7 @@ QT_BEGIN_NAMESPACE
 QML_DEFINE_NOCREATE_TYPE(QmlBinding);
 
 QmlBindingPrivate::QmlBindingPrivate()
-: inited(false), updating(false), enabled(true), mePtr(0)
+: updating(false), enabled(false), mePtr(0)
 {
 }
 
@@ -92,25 +94,6 @@ QmlMetaProperty QmlBinding::property() const
    return d->property; 
 }
 
-void QmlBinding::init()
-{
-    Q_D(QmlBinding);
-
-    if (d->inited)
-        return;
-    d->inited = true;
-    update();
-}
-
-void QmlBinding::forceUpdate()
-{
-    Q_D(QmlBinding);
-    if (!d->inited)
-        init();
-    else
-        update();
-}
-
 void QmlBinding::update()
 {
     Q_D(QmlBinding);
@@ -118,7 +101,7 @@ void QmlBinding::update()
 #ifdef Q_ENABLE_PERFORMANCE_LOG
     QFxPerfTimer<QFxPerf::BindableValueUpdate> bu;
 #endif
-    if (!d->inited || !d->enabled)
+    if (!d->enabled)
         return;
 
     if (!d->updating) {
@@ -168,6 +151,20 @@ void QmlBinding::setEnabled(bool e)
     Q_D(QmlBinding);
     d->enabled = e;
     setTrackChange(e);
+
+    if (e) {
+        d->mePtr = 0;
+        addToObject(d->property.object());
+        update();
+    } else {
+        removeFromObject();
+    }
+}
+
+int QmlBinding::propertyIndex()
+{
+    Q_D(QmlBinding);
+    return d->property.coreIndex();
 }
 
 bool QmlBinding::enabled() const
@@ -177,4 +174,47 @@ bool QmlBinding::enabled() const
     return d->enabled;
 }
 
+QString QmlBinding::expression() const
+{
+    return QmlExpression::expression();
+}
+
+QmlAbstractBinding::QmlAbstractBinding()
+: m_prevBinding(0), m_nextBinding(0)
+{
+}
+
+QmlAbstractBinding::~QmlAbstractBinding()
+{
+    removeFromObject();
+}
+
+void QmlAbstractBinding::addToObject(QObject *object)
+{
+    removeFromObject();
+
+    if (object) {
+        QmlDeclarativeData *data = QmlDeclarativeData::get(object, true);
+        m_nextBinding = data->bindings;
+        if (m_nextBinding) m_nextBinding->m_prevBinding = &m_nextBinding;
+        m_prevBinding = &data->bindings;
+        data->bindings = this;
+    }
+}
+
+void QmlAbstractBinding::removeFromObject()
+{
+    if (m_prevBinding) {
+        *m_prevBinding = m_nextBinding;
+        if (m_nextBinding) m_nextBinding->m_prevBinding = m_prevBinding;
+        m_prevBinding = 0;
+        m_nextBinding = 0;
+    }
+}
+
+QString QmlAbstractBinding::expression() const
+{
+    return QLatin1String("<Unknown>");
+}
+
 QT_END_NAMESPACE
diff --git a/src/declarative/qml/qmlbinding.h b/src/declarative/qml/qmlbinding.h
index c2182d5..ad25c16 100644
--- a/src/declarative/qml/qmlbinding.h
+++ b/src/declarative/qml/qmlbinding.h
@@ -54,9 +54,34 @@ QT_BEGIN_NAMESPACE
 
 QT_MODULE(Declarative)
 
+class QmlAbstractBinding 
+{
+public:
+    QmlAbstractBinding();
+    virtual ~QmlAbstractBinding();
+
+    virtual QString expression() const;
+
+    virtual void setEnabled(bool) = 0;
+    virtual int propertyIndex() = 0;
+
+    virtual void update() = 0;
+
+    void addToObject(QObject *);
+    void removeFromObject();
+
+private:
+    friend class QmlDeclarativeData;
+    friend class QmlMetaProperty;
+
+    QmlAbstractBinding **m_prevBinding;
+    QmlAbstractBinding  *m_nextBinding;
+};
+
 class QmlContext;
 class QmlBindingPrivate;
-class Q_DECLARATIVE_EXPORT QmlBinding : public QmlExpression
+class Q_DECLARATIVE_EXPORT QmlBinding : public QmlExpression, 
+                                        public QmlAbstractBinding
 {
 Q_OBJECT
 public:
@@ -67,12 +92,13 @@ public:
     void setTarget(const QmlMetaProperty &);
     QmlMetaProperty property() const;
 
-    void init();
-    void forceUpdate();
-
-    void setEnabled(bool);
     bool enabled() const;
 
+    // Inherited from  QmlAbstractBinding
+    virtual void setEnabled(bool);
+    virtual int propertyIndex();
+    virtual QString expression() const;
+
 public Q_SLOTS:
     void update();
 
diff --git a/src/declarative/qml/qmlbinding_p.h b/src/declarative/qml/qmlbinding_p.h
index ec1a04a..767e6af 100644
--- a/src/declarative/qml/qmlbinding_p.h
+++ b/src/declarative/qml/qmlbinding_p.h
@@ -65,13 +65,12 @@ class QmlBindingPrivate : public QmlExpressionPrivate
 public:
     QmlBindingPrivate();
 
-    bool inited:1;
     bool updating:1;
     bool enabled:1;
 
     QmlMetaProperty property;
 
-    QmlBinding **mePtr;
+    QmlAbstractBinding **mePtr;
 };
 
 QT_END_NAMESPACE
diff --git a/src/declarative/qml/qmlbindingoptimizations.cpp b/src/declarative/qml/qmlbindingoptimizations.cpp
new file mode 100644
index 0000000..235c034
--- /dev/null
+++ b/src/declarative/qml/qmlbindingoptimizations.cpp
@@ -0,0 +1,109 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qmlbindingoptimizations_p.h"
+#include <private/qmlcontext_p.h>
+
+QT_BEGIN_NAMESPACE
+
+
+QmlBindingIdOptimization::QmlBindingIdOptimization(QObject *object, 
+                                                   int propertyIdx,
+                                                   QmlContext *context, 
+                                                   int id)
+: m_prev(0), m_next(0), m_object(object), m_propertyIdx(propertyIdx), m_id(id)
+{
+    QmlAbstractExpression::setContext(context);
+}
+
+void QmlBindingIdOptimization::setEnabled(bool e)
+{
+    if (e) {
+        addToObject(m_object);
+        update();
+    } else {
+        removeFromObject();
+    }
+}
+
+int QmlBindingIdOptimization::propertyIndex()
+{
+    return m_propertyIdx;
+}
+
+void QmlBindingIdOptimization::update()
+{
+    QmlContextPrivate *ctxtPriv = 
+        static_cast<QmlContextPrivate *>(QObjectPrivate::get(context()));
+
+    if (ctxtPriv) {
+
+        if (!m_prev) {
+            m_next = ctxtPriv->idValues[m_id].bindings;
+            if (m_next) m_next->m_prev = &m_next;
+
+            m_prev = &ctxtPriv->idValues[m_id].bindings;
+            ctxtPriv->idValues[m_id].bindings = this;
+        }
+
+        QObject *o = ctxtPriv->idValues[m_id].data();
+        void *a[] = { &o, 0 };
+        QMetaObject::metacall(m_object, QMetaObject::WriteProperty, 
+                              m_propertyIdx, a);
+    } 
+}
+
+void QmlBindingIdOptimization::reset()
+{
+    if (m_prev) {
+        *m_prev = m_next;
+        if (m_next) m_next->m_prev = m_prev;
+        m_next = 0;
+        m_prev = 0;
+    }
+
+    QObject *o = 0;
+    void *a[] = { &o, 0 };
+    QMetaObject::metacall(m_object, QMetaObject::WriteProperty, 
+                          m_propertyIdx, a);
+}
+
+QT_END_NAMESPACE
diff --git a/src/declarative/qml/qmlbindingoptimizations_p.h b/src/declarative/qml/qmlbindingoptimizations_p.h
new file mode 100644
index 0000000..f50972d
--- /dev/null
+++ b/src/declarative/qml/qmlbindingoptimizations_p.h
@@ -0,0 +1,91 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QMLBINDINGOPTIMIZATIONS_P_H
+#define QMLBINDINGOPTIMIZATIONS_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <private/qmlexpression_p.h>
+#include <QtDeclarative/qmlbinding.h>
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+class QmlBindingIdOptimization : public QmlAbstractExpression, 
+                                 public QmlAbstractBinding
+{
+public:
+    QmlBindingIdOptimization(QObject *object, int propertyIdx,
+                             QmlContext *context, int id);
+
+    // Inherited from QmlAbstractBinding
+    virtual void setEnabled(bool);
+    virtual int propertyIndex();
+    virtual void update();
+
+    void reset();
+
+private:
+    QmlBindingIdOptimization **m_prev;
+    QmlBindingIdOptimization  *m_next;
+
+    QObject *m_object;
+    int m_propertyIdx;
+    int m_id;
+};
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif // QMLBINDINGOPTIMIZATIONS_P_H
+
diff --git a/src/declarative/qml/qmlcompiler.cpp b/src/declarative/qml/qmlcompiler.cpp
index 1c535d4..7c0964b 100644
--- a/src/declarative/qml/qmlcompiler.cpp
+++ b/src/declarative/qml/qmlcompiler.cpp
@@ -1394,6 +1394,7 @@ void QmlCompiler::addId(const QString &id, QmlParser::Object *obj)
     Q_ASSERT(obj->id == id);
     obj->idIndex = compileState.ids.count();
     compileState.ids.insert(id, obj);
+    compileState.idIndexes.insert(obj->idIndex, obj);
 }
 
 void QmlCompiler::addBindingReference(const BindingReference &ref)
@@ -2064,6 +2065,22 @@ void QmlCompiler::genBindingAssignment(QmlParser::Value *binding,
     const BindingReference &ref = compileState.bindings.value(binding);
 
     QmlInstruction store;
+
+    QmlBasicScript bs;
+    if (ref.isBasicScript) 
+        bs.load(ref.compiledData.constData() + sizeof(quint32));
+    if (bs.isSingleIdFetch()) {
+        int idIndex = bs.singleIdFetchIndex();
+        QmlParser::Object *idObj = compileState.idIndexes.value(idIndex);
+        if (canCoerce(prop->type, idObj)) {
+            store.type = QmlInstruction::StoreIdOptBinding;
+            store.assignIdOptBinding.id = idIndex;
+            store.assignIdOptBinding.property = prop->index;
+            output->bytecode << store;
+            return;
+        }
+    }
+        
     store.type = QmlInstruction::StoreCompiledBinding;
     store.assignBinding.value = output->indexForByteArray(ref.compiledData);
     store.assignBinding.context = ref.bindingContext.stack;
@@ -2109,6 +2126,7 @@ bool QmlCompiler::completeComponentBuild()
             binding.compiledData =
                 QByteArray(bs.compileData(), bs.compileDataSize());
             type = QmlExpressionPrivate::BasicScriptEngineData;
+            binding.isBasicScript = true;
         } else {
             type = QmlExpressionPrivate::PreTransformedQtScriptData;
 
@@ -2122,6 +2140,7 @@ bool QmlCompiler::completeComponentBuild()
                 QByteArray((const char *)&length, sizeof(quint32)) +
                 QByteArray((const char *)expression.constData(), 
                            expression.length() * sizeof(QChar));
+            binding.isBasicScript = false;
         }
         binding.compiledData.prepend(QByteArray((const char *)&type, 
                                                 sizeof(quint32)));
diff --git a/src/declarative/qml/qmlcompiler_p.h b/src/declarative/qml/qmlcompiler_p.h
index 094c05a..3d79e32 100644
--- a/src/declarative/qml/qmlcompiler_p.h
+++ b/src/declarative/qml/qmlcompiler_p.h
@@ -236,6 +236,7 @@ private:
         QmlParser::Variant expression;
         QmlParser::Property *property;
         QmlParser::Value *value;
+        bool isBasicScript;
         QByteArray compiledData;
         BindingContext bindingContext;
     };
@@ -247,6 +248,7 @@ private:
             : parserStatusCount(0), savedObjects(0), 
               pushedProperties(0), root(0) {}
         QHash<QString, QmlParser::Object *> ids;
+        QHash<int, QmlParser::Object *> idIndexes;
         int parserStatusCount;
         int savedObjects;
         int pushedProperties;
diff --git a/src/declarative/qml/qmlcomponent.cpp b/src/declarative/qml/qmlcomponent.cpp
index d4e383d..c30efca 100644
--- a/src/declarative/qml/qmlcomponent.cpp
+++ b/src/declarative/qml/qmlcomponent.cpp
@@ -533,11 +533,11 @@ void QmlComponent::completeCreate()
             QFxPerfTimer<QFxPerf::BindInit> bi;
 #endif
             for (int ii = 0; ii < d->bindValues.count(); ++ii) {
-                QmlEnginePrivate::SimpleList<QmlBinding> bv = 
+                QmlEnginePrivate::SimpleList<QmlAbstractBinding> bv = 
                     d->bindValues.at(ii);
                 for (int jj = 0; jj < bv.count; ++jj) {
                     if(bv.at(jj)) 
-                        bv.at(jj)->init();
+                        bv.at(jj)->setEnabled(true);
                 }
                 QmlEnginePrivate::clear(bv);
             }
diff --git a/src/declarative/qml/qmlcomponent_p.h b/src/declarative/qml/qmlcomponent_p.h
index a7a3230..4b459c2 100644
--- a/src/declarative/qml/qmlcomponent_p.h
+++ b/src/declarative/qml/qmlcomponent_p.h
@@ -88,7 +88,7 @@ public:
     int count;
     QmlCompiledData *cc;
 
-    QList<QmlEnginePrivate::SimpleList<QmlBinding> > bindValues;
+    QList<QmlEnginePrivate::SimpleList<QmlAbstractBinding> > bindValues;
     QList<QmlEnginePrivate::SimpleList<QmlParserStatus> > parserStatus;
 
     bool completePending;
diff --git a/src/declarative/qml/qmlcontext.cpp b/src/declarative/qml/qmlcontext.cpp
index 18ba906..451dbcc 100644
--- a/src/declarative/qml/qmlcontext.cpp
+++ b/src/declarative/qml/qmlcontext.cpp
@@ -47,6 +47,7 @@
 #include <qscriptengine.h>
 #include <QtCore/qvarlengtharray.h>
 #include <QtCore/qdebug.h>
+#include <private/qmlbindingoptimizations_p.h>
 
 // 6-bits
 #define MAXIMUM_DEFAULT_OBJECTS 63
@@ -82,6 +83,9 @@ void QmlContextPrivate::destroyed(ContextGuard *guard)
     if (parent && QObjectPrivate::get(parent)->wasDeleted) 
         return;
 
+    while(guard->bindings) 
+        guard->bindings->reset();
+
     for (int ii = 0; ii < idValueCount; ++ii) {
         if (&idValues[ii] == guard) {
             QMetaObject::activate(q, ii + notifyIndex, 0);
@@ -276,13 +280,13 @@ QmlContext::~QmlContext()
         (*iter)->d_func()->parent = 0;
     }
 
-    QmlExpressionPrivate *expression = d->expressions;
+    QmlAbstractExpression *expression = d->expressions;
     while (expression) {
-        QmlExpressionPrivate *nextExpression = expression->nextExpression;
+        QmlAbstractExpression *nextExpression = expression->m_nextExpression;
 
-        expression->ctxt = 0;
-        expression->prevExpression = 0;
-        expression->nextExpression = 0;
+        expression->m_context = 0;
+        expression->m_prevExpression = 0;
+        expression->m_nextExpression = 0;
 
         expression = nextExpression;
     }
diff --git a/src/declarative/qml/qmlcontext_p.h b/src/declarative/qml/qmlcontext_p.h
index 0424a85..b5479d9 100644
--- a/src/declarative/qml/qmlcontext_p.h
+++ b/src/declarative/qml/qmlcontext_p.h
@@ -68,6 +68,8 @@ class QmlExpression;
 class QmlEngine;
 class QmlExpression;
 class QmlExpressionPrivate;
+class QmlAbstractExpression;
+class QmlBindingIdOptimization;
 
 class QmlContextPrivate : public QObjectPrivate
 {
@@ -104,13 +106,15 @@ public:
     void invalidateEngines();
     QSet<QmlContext *> childContexts;
 
-    QmlExpressionPrivate *expressions;
+    QmlAbstractExpression *expressions;
 
     QObjectList contextObjects;
 
     struct ContextGuard : public QGuard<QObject>
     {
+        ContextGuard() : priv(0), bindings(0) {}
         QmlContextPrivate *priv;
+        QmlBindingIdOptimization *bindings;
         ContextGuard &operator=(QObject *obj) {
             (QGuard<QObject>&)*this = obj; return *this;
         }
diff --git a/src/declarative/qml/qmldeclarativedata_p.h b/src/declarative/qml/qmldeclarativedata_p.h
index 8d30bcc..5a51eb7 100644
--- a/src/declarative/qml/qmldeclarativedata_p.h
+++ b/src/declarative/qml/qmldeclarativedata_p.h
@@ -58,7 +58,7 @@
 QT_BEGIN_NAMESPACE
 
 class QmlCompiledData;
-class QmlBinding;
+class QmlAbstractBinding;
 class QmlDeclarativeData : public QDeclarativeData
 {
 public:
@@ -67,7 +67,7 @@ public:
     virtual void destroyed(QObject *);
 
     QmlContext *context;
-    QmlBinding *bindings;
+    QmlAbstractBinding *bindings;
 
     QmlCompiledData *deferredComponent; // Can't this be found from the context?
     unsigned int deferredIdx;
diff --git a/src/declarative/qml/qmlengine.cpp b/src/declarative/qml/qmlengine.cpp
index 09539bc..bdbf2e7 100644
--- a/src/declarative/qml/qmlengine.cpp
+++ b/src/declarative/qml/qmlengine.cpp
@@ -121,16 +121,8 @@ QmlEnginePrivate::~QmlEnginePrivate()
         clear(parserStatus[ii]);
 }
 
-void QmlEnginePrivate::clear(SimpleList<QmlBinding> &bvs)
+void QmlEnginePrivate::clear(SimpleList<QmlAbstractBinding> &bvs)
 {
-    for (int ii = 0; ii < bvs.count; ++ii) {
-        QmlBinding *bv = bvs.at(ii);
-        if(bv) {
-            QmlBindingPrivate *p =
-                static_cast<QmlBindingPrivate *>(QObjectPrivate::get(bv));
-            p->mePtr = 0;
-        }
-    }
     bvs.clear();
 }
 
@@ -522,6 +514,15 @@ void QmlDeclarativeData::destroyed(QObject *object)
     if (context)
         static_cast<QmlContextPrivate *>(QObjectPrivate::get(context))->contextObjects.removeAll(object);
 
+    QmlAbstractBinding *binding = bindings;
+    while (binding) {
+        QmlAbstractBinding *next = binding->m_nextBinding;
+        binding->m_prevBinding = 0;
+        binding->m_nextBinding = 0;
+        delete binding;
+        binding = next;
+    }
+
     delete this;
 }
 
diff --git a/src/declarative/qml/qmlengine_p.h b/src/declarative/qml/qmlengine_p.h
index 602321d..d2e3ef4 100644
--- a/src/declarative/qml/qmlengine_p.h
+++ b/src/declarative/qml/qmlengine_p.h
@@ -86,6 +86,7 @@ class QmlValueTypeScriptClass;
 class QScriptEngineDebugger;
 class QNetworkReply;
 class QNetworkAccessManager;
+class QmlAbstractBinding;
 
 class QmlEnginePrivate : public QObjectPrivate
 {
@@ -160,10 +161,10 @@ public:
         }
     };
 
-    static void clear(SimpleList<QmlBinding> &);
+    static void clear(SimpleList<QmlAbstractBinding> &);
     static void clear(SimpleList<QmlParserStatus> &);
 
-    QList<SimpleList<QmlBinding> > bindValues;
+    QList<SimpleList<QmlAbstractBinding> > bindValues;
     QList<SimpleList<QmlParserStatus> > parserStatus;
 
     QmlComponent *rootComponent;
diff --git a/src/declarative/qml/qmlenginedebug.cpp b/src/declarative/qml/qmlenginedebug.cpp
index c26f3b7..0e78cad 100644
--- a/src/declarative/qml/qmlenginedebug.cpp
+++ b/src/declarative/qml/qmlenginedebug.cpp
@@ -97,7 +97,7 @@ QmlEngineDebugServer::propertyData(QObject *obj, int propIdx)
 
     rv.type = QmlObjectProperty::Unknown;
     rv.name = prop.name();
-    QmlBinding *binding = QmlMetaProperty(obj, rv.name).binding();
+    QmlAbstractBinding *binding = QmlMetaProperty(obj, rv.name).binding();
     if (binding)
         rv.binding = binding->expression();
 
diff --git a/src/declarative/qml/qmlexpression.cpp b/src/declarative/qml/qmlexpression.cpp
index 6e9a7a1..f8e78d7 100644
--- a/src/declarative/qml/qmlexpression.cpp
+++ b/src/declarative/qml/qmlexpression.cpp
@@ -51,33 +51,23 @@ Q_DECLARE_METATYPE(QList<QObject *>);
 QT_BEGIN_NAMESPACE
 
 QmlExpressionPrivate::QmlExpressionPrivate()
-: nextExpression(0), prevExpression(0), ctxt(0), expressionFunctionValid(false), expressionRewritten(false), me(0), trackChange(true), line(-1), guardList(0), guardListLength(0)
+: expressionFunctionValid(false), expressionRewritten(false), me(0), 
+  trackChange(true), line(-1), guardList(0), guardListLength(0)
 {
 }
 
 void QmlExpressionPrivate::init(QmlContext *ctxt, const QString &expr, 
                                 QObject *me)
 {
-    Q_Q(QmlExpression);
-
     expression = expr;
 
-    this->ctxt = ctxt;
-    if (ctxt) {
-        QmlContextPrivate *cp = ctxt->d_func();
-        nextExpression = cp->expressions;
-        if (nextExpression) nextExpression->prevExpression = &nextExpression;
-        prevExpression = &cp->expressions;
-        cp->expressions = this;
-    }
+    QmlAbstractExpression::setContext(ctxt);
     this->me = me;
 }
 
 void QmlExpressionPrivate::init(QmlContext *ctxt, void *expr, QmlRefCount *rc, 
                                 QObject *me)
 {
-    Q_Q(QmlExpression);
-
     quint32 *data = (quint32 *)expr;
     Q_ASSERT(*data == BasicScriptEngineData || 
              *data == PreTransformedQtScriptData);
@@ -88,14 +78,7 @@ void QmlExpressionPrivate::init(QmlContext *ctxt, void *expr, QmlRefCount *rc,
         expressionRewritten = true;
     }
 
-    this->ctxt = ctxt;
-    if (ctxt) {
-        QmlContextPrivate *cp = ctxt->d_func();
-        nextExpression = cp->expressions;
-        if (nextExpression) nextExpression->prevExpression = &nextExpression;
-        prevExpression = &cp->expressions;
-        cp->expressions = this;
-    }
+    QmlAbstractExpression::setContext(ctxt);
     this->me = me;
 }
 
@@ -159,12 +142,6 @@ QmlExpression::QmlExpression(QmlContext *ctxt, const QString &expression,
 */
 QmlExpression::~QmlExpression()
 {
-    Q_D(QmlExpression);
-    if (d->prevExpression) {
-        *(d->prevExpression) = d->nextExpression;
-        if (d->nextExpression) 
-            d->nextExpression->prevExpression = d->prevExpression;
-    }
 }
 
 /*!
@@ -174,7 +151,7 @@ QmlExpression::~QmlExpression()
 QmlEngine *QmlExpression::engine() const
 {
     Q_D(const QmlExpression);
-    return d->ctxt?d->ctxt->engine():0;
+    return d->context()?d->context()->engine():0;
 }
 
 /*!
@@ -184,7 +161,7 @@ QmlEngine *QmlExpression::engine() const
 QmlContext *QmlExpression::context() const
 {
     Q_D(const QmlExpression);
-    return d->ctxt;
+    return d->context();
 }
 
 /*!
@@ -230,9 +207,7 @@ QVariant QmlExpressionPrivate::evalSSE()
     QFxPerfTimer<QFxPerf::BindValueSSE> perfsse;
 #endif
 
-    QmlContextPrivate *ctxtPriv = ctxt->d_func();
-
-    QVariant rv = sse.run(ctxt, me);
+    QVariant rv = sse.run(context(), me);
 
     return rv;
 }
@@ -243,8 +218,8 @@ QVariant QmlExpressionPrivate::evalQtScript()
     QFxPerfTimer<QFxPerf::BindValueQt> perfqt;
 #endif
 
-    QmlContextPrivate *ctxtPriv = ctxt->d_func();
-    QmlEngine *engine = ctxt->engine();
+    QmlContextPrivate *ctxtPriv = context()->d_func();
+    QmlEngine *engine = context()->engine();
 
     if (me)
        ctxtPriv->defaultObjects.insert(ctxtPriv->highPriorityCount, me);
@@ -347,7 +322,7 @@ QVariant QmlExpression::value()
     Q_D(QmlExpression);
 
     QVariant rv;
-    if (!d->ctxt || !engine() || (!d->sse.isValid() && d->expression.isEmpty()))
+    if (!d->context() || (!d->sse.isValid() && d->expression.isEmpty()))
         return rv;
 
 #ifdef Q_ENABLE_PERFORMANCE_LOG
@@ -574,5 +549,52 @@ void QmlExpressionPrivate::updateGuards(const QPODVector<QmlEnginePrivate::Captu
     calling QmlExpression::value()) before this signal will be emitted.
 */
 
+QmlAbstractExpression::QmlAbstractExpression()
+: m_context(0), m_prevExpression(0), m_nextExpression(0)
+{
+}
+
+QmlAbstractExpression::~QmlAbstractExpression()
+{
+    if (m_prevExpression) {
+        *m_prevExpression = m_nextExpression;
+        if (m_nextExpression) 
+            m_nextExpression->m_prevExpression = m_prevExpression;
+    }
+}
+
+QmlContext *QmlAbstractExpression::context() const
+{
+    return m_context;
+}
+
+void QmlAbstractExpression::setContext(QmlContext *context)
+{
+    if (m_prevExpression) {
+        *m_prevExpression = m_nextExpression;
+        if (m_nextExpression) 
+            m_nextExpression->m_prevExpression = m_prevExpression;
+        m_prevExpression = 0;
+        m_nextExpression = 0;
+    }
+
+    m_context = context;
+
+    if (m_context) {
+        QmlContextPrivate *cp = 
+            static_cast<QmlContextPrivate *>(QObjectPrivate::get(m_context));
+        m_nextExpression = cp->expressions;
+        if (m_nextExpression) 
+            m_nextExpression->m_prevExpression = &m_nextExpression;
+        m_prevExpression = &cp->expressions;
+        cp->expressions = this;
+    }
+}
+
+bool QmlAbstractExpression::isValid() const
+{
+    return m_context != 0;
+}
+
 QT_END_NAMESPACE
 
diff --git a/src/declarative/qml/qmlexpression_p.h b/src/declarative/qml/qmlexpression_p.h
index bf95c0e0..997bf8d 100644
--- a/src/declarative/qml/qmlexpression_p.h
+++ b/src/declarative/qml/qmlexpression_p.h
@@ -61,19 +61,33 @@
 
 QT_BEGIN_NAMESPACE
 
+class QmlAbstractExpression
+{
+public:
+    QmlAbstractExpression();
+    virtual ~QmlAbstractExpression();
+
+    bool isValid() const;
+
+    QmlContext *context() const;
+    void setContext(QmlContext *);
+
+private:
+    friend class QmlContext;
+    QmlContext *m_context;
+    QmlAbstractExpression **m_prevExpression;
+    QmlAbstractExpression  *m_nextExpression;
+};
+
 class QmlExpression;
 class QString;
-class QmlExpressionPrivate : public QObjectPrivate
+class QmlExpressionPrivate : public QObjectPrivate, public QmlAbstractExpression
 {
     Q_DECLARE_PUBLIC(QmlExpression)
 public:
     QmlExpressionPrivate();
     ~QmlExpressionPrivate();
 
-    // Forms the QmlContext "expressions" linked list
-    QmlExpressionPrivate *nextExpression;
-    QmlExpressionPrivate **prevExpression;
-
     enum CompiledDataType {
         BasicScriptEngineData = 1,
         PreTransformedQtScriptData = 2
@@ -82,7 +96,6 @@ public:
     void init(QmlContext *, const QString &, QObject *);
     void init(QmlContext *, void *, QmlRefCount *, QObject *);
 
-    QmlContext *ctxt;
     QString expression;
     bool expressionFunctionValid:1;
     bool expressionRewritten:1;
diff --git a/src/declarative/qml/qmlinstruction_p.h b/src/declarative/qml/qmlinstruction_p.h
index e6b8de6..16bc8cf 100644
--- a/src/declarative/qml/qmlinstruction_p.h
+++ b/src/declarative/qml/qmlinstruction_p.h
@@ -125,6 +125,7 @@ public:
         AssignCustomType,          /* assignCustomType */
 
         StoreCompiledBinding,     /* assignBinding */
+        StoreIdOptBinding,        /* assignIdOptBinding */
         StoreValueSource,         /* assignValueSource */
 
         BeginObject,              /* begin */
@@ -189,6 +190,10 @@ public:
         } assignBinding;
         struct {
             int property;
+            int id;
+        } assignIdOptBinding;
+        struct {
+            int property;
         } fetch;
         struct {
             int property;
diff --git a/src/declarative/qml/qmlmetaproperty.cpp b/src/declarative/qml/qmlmetaproperty.cpp
index 64dd9cd..d986077 100644
--- a/src/declarative/qml/qmlmetaproperty.cpp
+++ b/src/declarative/qml/qmlmetaproperty.cpp
@@ -51,6 +51,7 @@
 #include <QtCore/qdebug.h>
 #include <QtDeclarative/qmlengine.h>
 #include <private/qmlengine_p.h>
+#include <private/qmldeclarativedata_p.h>
 
 Q_DECLARE_METATYPE(QList<QObject *>);
 
@@ -509,20 +510,21 @@ QMetaProperty QmlMetaProperty::property() const
     Returns the binding associated with this property, or 0 if no binding 
     exists.
 */
-QmlBinding *QmlMetaProperty::binding() const
+QmlAbstractBinding *QmlMetaProperty::binding() const
 {
     if (!isProperty() || (type() & Attached) || !d->object)
         return 0;
 
-    const QObjectList &children = object()->children();
-    for (QObjectList::ConstIterator iter = children.begin();
-            iter != children.end(); ++iter) {
-        QObject *child = *iter;
-        if (child->metaObject() == &QmlBinding::staticMetaObject) {
-            QmlBinding *v = static_cast<QmlBinding *>(child);
-            if (v->property() == *this && v->enabled())
-                return v;
-        }
+    QmlDeclarativeData *data = QmlDeclarativeData::get(d->object);
+    if (!data) 
+        return 0;
+
+    QmlAbstractBinding *binding = data->bindings;
+    while (binding) {
+        // ### This wont work for value types
+        if (binding->propertyIndex() == d->coreIdx)
+            return binding; 
+        binding = binding->m_nextBinding;
     }
     return 0;
 }
@@ -534,41 +536,32 @@ QmlBinding *QmlMetaProperty::binding() const
     \a binding will be enabled, and the returned binding (if any) will be
     disabled.
 */
-QmlBinding *QmlMetaProperty::setBinding(QmlBinding *binding) const
+QmlAbstractBinding *
+QmlMetaProperty::setBinding(QmlAbstractBinding *newBinding) const
 {
     if (!isProperty() || (type() & Attached) || !d->object)
         return 0;
 
-    const QObjectList &children = object()->children();
-    for (QObjectList::ConstIterator iter = children.begin();
-            iter != children.end(); ++iter) {
-        QObject *child = *iter;
-        if (child->metaObject() == &QmlBinding::staticMetaObject) {
-            QmlBinding *v = static_cast<QmlBinding *>(child);
-            if (v->property() == *this && v->enabled()) {
-
-                v->setEnabled(false);
-
-                if (binding) {
-                    binding->setParent(object());
-                    binding->setTarget(*this);
-                    binding->setEnabled(true);
-                    binding->forceUpdate();
-                }
+    QmlDeclarativeData *data = QmlDeclarativeData::get(d->object, true);
 
-                return v;
+    QmlAbstractBinding *binding = data->bindings;
+    while (binding) {
+        // ### This wont work for value types
+        if (binding->propertyIndex() == d->coreIdx) {
+            binding->setEnabled(false);
 
-            }
+            if (newBinding) 
+                newBinding->setEnabled(true);
+
+            return binding; // ### QmlAbstractBinding;
         }
-    }
 
-    if (binding) {
-        binding->setParent(object());
-        binding->setTarget(*this);
-        binding->setEnabled(true);
-        binding->forceUpdate();
+        binding = binding->m_nextBinding;
     }
 
+    if (newBinding)
+        newBinding->setEnabled(true);
+
     return 0;
 }
 
diff --git a/src/declarative/qml/qmlmetaproperty.h b/src/declarative/qml/qmlmetaproperty.h
index 434ff55..7b9ff47 100644
--- a/src/declarative/qml/qmlmetaproperty.h
+++ b/src/declarative/qml/qmlmetaproperty.h
@@ -52,7 +52,7 @@ QT_BEGIN_NAMESPACE
 QT_MODULE(Declarative)
 
 class QObject;
-class QmlBinding;
+class QmlAbstractBinding;
 class QStringList;
 class QVariant;
 struct QMetaObject;
@@ -122,8 +122,8 @@ public:
 
     QMetaProperty property() const;
 
-    QmlBinding *binding() const;
-    QmlBinding *setBinding(QmlBinding *) const;
+    QmlAbstractBinding *binding() const;
+    QmlAbstractBinding *setBinding(QmlAbstractBinding *) const;
 
     static QmlMetaProperty createProperty(QObject *, const QString &);
 
diff --git a/src/declarative/qml/qmlvme.cpp b/src/declarative/qml/qmlvme.cpp
index ffe8591..dccf5c4 100644
--- a/src/declarative/qml/qmlvme.cpp
+++ b/src/declarative/qml/qmlvme.cpp
@@ -65,6 +65,7 @@
 #include <QtCore/qvarlengtharray.h>
 #include <private/qmlbinding_p.h>
 #include <private/qmlcontext_p.h>
+#include <private/qmlbindingoptimizations_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -138,7 +139,7 @@ QObject *QmlVME::run(QStack<QObject *> &stack, QmlContext *ctxt, QmlCompiledData
     const QList<float> &floatData = comp->floatData;
 
 
-    QmlEnginePrivate::SimpleList<QmlBinding> bindValues;
+    QmlEnginePrivate::SimpleList<QmlAbstractBinding> bindValues;
     QmlEnginePrivate::SimpleList<QmlParserStatus> parserStatus;
 
     QStack<ListInstance> qliststack;
@@ -154,7 +155,7 @@ QObject *QmlVME::run(QStack<QObject *> &stack, QmlContext *ctxt, QmlCompiledData
         case QmlInstruction::Init:
             {
                 if (instr.init.bindingsSize) 
-                    bindValues = QmlEnginePrivate::SimpleList<QmlBinding>(instr.init.bindingsSize);
+                    bindValues = QmlEnginePrivate::SimpleList<QmlAbstractBinding>(instr.init.bindingsSize);
                 if (instr.init.parserStatusSize)
                     parserStatus = QmlEnginePrivate::SimpleList<QmlParserStatus>(instr.init.parserStatusSize);
 
@@ -543,12 +544,24 @@ QObject *QmlVME::run(QStack<QObject *> &stack, QmlContext *ctxt, QmlCompiledData
                 QmlBindingPrivate *p = 
                     static_cast<QmlBindingPrivate *>(QObjectPrivate::get(bind));
                 p->mePtr = &bindValues.values[bindValues.count - 1];
-                QFx_setParent_noEvent(bind, target);
+                bind->addToObject(target);
 
                 bind->setTarget(mp);
             }
             break;
 
+        case QmlInstruction::StoreIdOptBinding:
+            {
+                QObject *target = stack.top();
+
+                QmlBindingIdOptimization *bind = 
+                    new QmlBindingIdOptimization(target, instr.assignIdOptBinding.property, ctxt, instr.assignIdOptBinding.id);
+                bindValues.append(bind);
+                // ### Need a mePtr
+                bind->addToObject(target);
+            } 
+            break;
+
         case QmlInstruction::StoreValueSource:
             {
                 QmlPropertyValueSource *vs = 
diff --git a/src/declarative/util/qmlsetproperties.cpp b/src/declarative/util/qmlsetproperties.cpp
index 1cd4a79..482405c 100644
--- a/src/declarative/util/qmlsetproperties.cpp
+++ b/src/declarative/util/qmlsetproperties.cpp
@@ -334,9 +334,10 @@ QmlSetProperties::ActionList QmlSetProperties::actions()
             if (d->isExplicit) {
                 a.toValue = d->expressions.at(ii).second->value();
             } else {
-                a.toBinding = new QmlBinding(d->expressions.at(ii).second->expression(), object(), qmlContext(this));
+                QmlBinding *newBinding = new QmlBinding(d->expressions.at(ii).second->expression(), object(), qmlContext(this));
+                newBinding->setTarget(prop);
+                a.toBinding = newBinding;
                 a.deletableToBinding = true;
-                a.toBinding->setTarget(prop);
             }
 
             list << a;
diff --git a/src/declarative/util/qmlstate.h b/src/declarative/util/qmlstate.h
index 9eb7aee..46659c6 100644
--- a/src/declarative/util/qmlstate.h
+++ b/src/declarative/util/qmlstate.h
@@ -70,8 +70,8 @@ public:
     QVariant fromValue;
     QVariant toValue;
 
-    QmlBinding *fromBinding;
-    QmlBinding *toBinding;
+    QmlAbstractBinding *fromBinding;
+    QmlAbstractBinding *toBinding;
     ActionEvent *event;
 
     //strictly for matching
diff --git a/src/declarative/util/qmlstate_p.h b/src/declarative/util/qmlstate_p.h
index b601b57..63fc6da 100644
--- a/src/declarative/util/qmlstate_p.h
+++ b/src/declarative/util/qmlstate_p.h
@@ -83,7 +83,7 @@ public:
 
     QmlMetaProperty property;
     QVariant value;
-    QmlBinding *binding;
+    QmlAbstractBinding *binding;
     QObject *specifiedObject;
     QString specifiedProperty;
     ActionEvent *event;
diff --git a/src/declarative/util/qmltransitionmanager.cpp b/src/declarative/util/qmltransitionmanager.cpp
index f04a821..3e2e05f 100644
--- a/src/declarative/util/qmltransitionmanager.cpp
+++ b/src/declarative/util/qmltransitionmanager.cpp
@@ -94,7 +94,6 @@ void QmlTransitionManagerPrivate::applyBindings()
     foreach(const Action &action, bindingsList) {
         if (action.toBinding) {
             action.property.setBinding(action.toBinding);
-            action.toBinding->forceUpdate();
         } else if (action.event) {
             if (action.reverseEvent)
                 action.event->reverse();
@@ -146,7 +145,6 @@ void QmlTransitionManager::transition(const QList<Action> &list,
             const Action &action = applyList.at(ii);
             if (action.toBinding) {
                 action.property.setBinding(action.toBinding);
-                action.toBinding->forceUpdate();
             } else if (!action.event) {
                 action.property.write(action.toValue);
             } else if (action.event->isReversable()) {