Optimize QML "parent" property access

For properties that are as important as "parent", QML cannot afford the
overhead of a signal/slot connection.

4 files changed, 91 insertions, 16 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativeitem.cpp b/src/declarative/graphicsitems/qdeclarativeitem.cpp
index e6ade00..ee0682a 100644
--- a/src/declarative/graphicsitems/qdeclarativeitem.cpp
+++ b/src/declarative/graphicsitems/qdeclarativeitem.cpp
@@ -1554,6 +1554,14 @@ void QDeclarativeItemPrivate::transform_clear(QDeclarativeListProperty<QGraphics
     }
 }
 
+void QDeclarativeItemPrivate::parentProperty(QObject *o, void *rv, QDeclarativeNotifierEndpoint *e) 
+{
+    QDeclarativeItem *item = static_cast<QDeclarativeItem*>(o);
+    if (e) 
+        e->connect(&item->d_func()->parentNotifier);
+    *((QDeclarativeItem **)rv) = item->parentItem();
+}
+
 /*!
     \qmlproperty list<Object> Item::data
     \default
@@ -2539,10 +2547,11 @@ bool QDeclarativeItem::sceneEvent(QEvent *event)
 QVariant QDeclarativeItem::itemChange(GraphicsItemChange change,
                                        const QVariant &value)
 {
-    Q_D(const QDeclarativeItem);
+    Q_D(QDeclarativeItem);
     switch (change) {
     case ItemParentHasChanged:
         emit parentChanged(parentItem());
+        d->parentNotifier.notify();
         break;
     case ItemChildAddedChange:
     case ItemChildRemovedChange:
diff --git a/src/declarative/graphicsitems/qdeclarativeitem_p.h b/src/declarative/graphicsitems/qdeclarativeitem_p.h
index 56b0d77..4828f4e 100644
--- a/src/declarative/graphicsitems/qdeclarativeitem_p.h
+++ b/src/declarative/graphicsitems/qdeclarativeitem_p.h
@@ -62,6 +62,8 @@
 
 #include <private/qdeclarativestate_p.h>
 #include <private/qdeclarativenullablevalue_p_p.h>
+#include <private/qdeclarativenotifier_p.h>
+
 #include <qdeclarative.h>
 #include <qdeclarativecontext.h>
 
@@ -160,6 +162,10 @@ public:
     static QGraphicsTransform *transform_at(QDeclarativeListProperty<QGraphicsTransform> *list, int);
     static void transform_clear(QDeclarativeListProperty<QGraphicsTransform> *list);
 
+    // Accelerated property accessors
+    QDeclarativeNotifier parentNotifier;
+    static void parentProperty(QObject *o, void *rv, QDeclarativeNotifierEndpoint *e);
+
     QDeclarativeAnchors *anchors() {
         if (!_anchors) {
             Q_Q(QDeclarativeItem);
diff --git a/src/declarative/qml/qdeclarativecompiledbindings.cpp b/src/declarative/qml/qdeclarativecompiledbindings.cpp
index 1acca2f..67750a4 100644
--- a/src/declarative/qml/qdeclarativecompiledbindings.cpp
+++ b/src/declarative/qml/qdeclarativecompiledbindings.cpp
@@ -53,11 +53,15 @@
 #include <QtCore/qnumeric.h>
 #include <private/qdeclarativeanchors_p_p.h>
 #include <private/qdeclarativeglobal_p.h>
+#include <private/qdeclarativefastproperties_p.h>
 
 QT_BEGIN_NAMESPACE
 
 DEFINE_BOOL_CONFIG_OPTION(qmlExperimental, QML_EXPERIMENTAL);
 DEFINE_BOOL_CONFIG_OPTION(qmlDisableOptimizer, QML_DISABLE_OPTIMIZER);
+DEFINE_BOOL_CONFIG_OPTION(qmlDisableFastProperties, QML_DISABLE_FAST_PROPERTIES);
+
+Q_GLOBAL_STATIC(QDeclarativeFastProperties, fastProperties);
 
 using namespace QDeclarativeJS;
 
@@ -334,6 +338,8 @@ struct Instr {
         Subscribe,               // subscribe
         SubscribeId,             // subscribe
 
+        FetchAndSubscribe,       // fetchAndSubscribe
+
         LoadId,                  // load
         LoadScope,               // load
         LoadRoot,                // load
@@ -433,6 +439,14 @@ struct Instr {
             qint8 output;
             qint8 objectReg;
             quint8 exceptionId;
+            quint16 subscription;
+            quint16 function;
+        } fetchAndSubscribe;
+        struct {
+            quint8 type;
+            qint8 output;
+            qint8 objectReg;
+            quint8 exceptionId;
             quint32 index;
         } fetch;
         struct {
@@ -937,6 +951,9 @@ static void dumpInstruction(const Instr *instr)
     case Instr::SubscribeId:
         qWarning().nospace() << "SubscribeId" << "\t\t" << instr->subscribe.offset << "\t" << instr->subscribe.reg << "\t" << instr->subscribe.index;
         break;
+    case Instr::FetchAndSubscribe:
+        qWarning().nospace() << "FetchAndSubscribe" << "\t" << instr->fetchAndSubscribe.output << "\t" << instr->fetchAndSubscribe.objectReg << "\t" << instr->fetchAndSubscribe.subscription;
+        break;
     case Instr::LoadId:
         qWarning().nospace() << "LoadId" << "\t\t\t" << instr->load.index << "\t" << instr->load.reg;
         break;
@@ -1070,6 +1087,8 @@ void QDeclarativeCompiledBindingsPrivate::run(int instrIndex,
                                               QDeclarativeContextData *context, QDeclarativeDelayedError *error,
                                               QObject *scope, QObject *output)
 {
+    Q_Q(QDeclarativeCompiledBindings);
+
     error->removeError();
 
     Register registers[32];
@@ -1081,6 +1100,7 @@ void QDeclarativeCompiledBindingsPrivate::run(int instrIndex,
     instr += instrIndex;
     const char *data = program->data();
 
+    // return;
 #ifdef COMPILEDBINDINGS_DEBUG
     qWarning().nospace() << "Begin binding run";
 #endif
@@ -1107,6 +1127,32 @@ void QDeclarativeCompiledBindingsPrivate::run(int instrIndex,
     }
         break;
 
+    case Instr::FetchAndSubscribe:
+    {
+        const Register &input = registers[instr->fetchAndSubscribe.objectReg];
+        Register &output = registers[instr->fetchAndSubscribe.output];
+
+        if (input.isUndefined()) {
+            throwException(instr->fetchAndSubscribe.exceptionId, error, program, context);
+            return;
+        }
+
+        QObject *object = input.getQObject();
+        if (!object) {
+            output.setUndefined();
+        } else {
+            int subIdx = instr->fetchAndSubscribe.subscription;
+            QDeclarativeCompiledBindingsPrivate::Subscription *sub = 0;
+            if (subIdx != -1) {
+                sub = (subscriptions + subIdx);
+                sub->target = q;
+                sub->targetMethod = methodCount + subIdx; 
+            }
+            fastProperties()->accessor(instr->fetchAndSubscribe.function)(object, output.typeDataPtr(), sub);
+        }
+    }
+        break;
+
     case Instr::LoadId:
         registers[instr->load.reg].setQObject(context->idValues[instr->load.index].data());
         break;
@@ -2376,29 +2422,41 @@ bool QDeclarativeBindingCompilerPrivate::buildName(QStringList &name,
     return true;
 }
 
-
 bool QDeclarativeBindingCompilerPrivate::fetch(Result &rv, const QMetaObject *mo, int reg, 
-                                      int idx, const QStringList &subName, QDeclarativeJS::AST::ExpressionNode *node)
+                                               int idx, const QStringList &subName, 
+                                               QDeclarativeJS::AST::ExpressionNode *node)
 {
     QMetaProperty prop = mo->property(idx);
     rv.metaObject = 0;
     rv.type = 0;
 
-    if (subscription(subName, &rv) && prop.hasNotifySignal() && prop.notifySignalIndex() != -1) {
-        Instr sub;
-        sub.common.type = Instr::Subscribe;
-        sub.subscribe.offset = subscriptionIndex(subName);
-        sub.subscribe.reg = reg;
-        sub.subscribe.index = prop.notifySignalIndex();
-        bytecode << sub;
-    }
+    int fastFetchIndex = fastProperties()->accessorIndexForProperty(mo, idx);
 
     Instr fetch;
-    fetch.common.type = Instr::Fetch;
-    fetch.fetch.objectReg = reg;
-    fetch.fetch.index = idx;
-    fetch.fetch.output = reg;
-    fetch.fetch.exceptionId = exceptionId(node);
+
+    if (!qmlDisableFastProperties() && fastFetchIndex != -1) {
+        fetch.common.type = Instr::FetchAndSubscribe;
+        fetch.fetchAndSubscribe.objectReg = reg;
+        fetch.fetchAndSubscribe.output = reg;
+        fetch.fetchAndSubscribe.function = fastFetchIndex;
+        fetch.fetchAndSubscribe.subscription = subscriptionIndex(subName);
+        fetch.fetchAndSubscribe.exceptionId = exceptionId(node);
+    } else {
+        if (subscription(subName, &rv) && prop.hasNotifySignal() && prop.notifySignalIndex() != -1) {
+            Instr sub;
+            sub.common.type = Instr::Subscribe;
+            sub.subscribe.offset = subscriptionIndex(subName);
+            sub.subscribe.reg = reg;
+            sub.subscribe.index = prop.notifySignalIndex();
+            bytecode << sub;
+        }
+
+        fetch.common.type = Instr::Fetch;
+        fetch.fetch.objectReg = reg;
+        fetch.fetch.index = idx;
+        fetch.fetch.output = reg;
+        fetch.fetch.exceptionId = exceptionId(node);
+    }
 
     rv.type = prop.userType();
     rv.metaObject = engine->metaObjectForType(rv.type);
diff --git a/src/declarative/qml/qml.pri b/src/declarative/qml/qml.pri
index 49888c3..fc8ba50 100644
--- a/src/declarative/qml/qml.pri
+++ b/src/declarative/qml/qml.pri
@@ -31,6 +31,7 @@ SOURCES += \
     $$PWD/qdeclarativerewrite.cpp \
     $$PWD/qdeclarativevaluetype.cpp \
     $$PWD/qdeclarativecompiledbindings.cpp \
+    $$PWD/qdeclarativefastproperties.cpp \
     $$PWD/qdeclarativexmlhttprequest.cpp \
     $$PWD/qdeclarativesqldatabase.cpp \
     $$PWD/qmetaobjectbuilder.cpp \
@@ -103,6 +104,7 @@ HEADERS += \
     $$PWD/qbitfield_p.h \
     $$PWD/qdeclarativevaluetype_p.h \
     $$PWD/qdeclarativecompiledbindings_p.h \
+    $$PWD/qdeclarativefastproperties_p.h \
     $$PWD/qdeclarativexmlhttprequest_p.h \
     $$PWD/qdeclarativesqldatabase_p.h \
     $$PWD/qmetaobjectbuilder_p.h \