Optimize QObjectPrivate::isSignalConnected

It can be seen in the GraphicsView benchmark.
This function has to be as fast as possible.
Make the function inline.

We do not need 64bit for the connectedSignals bit array because
it is very unlikely that an object will have more than 32 signals.
(In Qt 4.5 it could have hapenned as the slot were counting in
the index)

Reviewed-by: bnilsen
Reviewed-by: Brad

2 files changed, 26 insertions, 42 deletions

diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index 95602d9..4321c59 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -145,8 +145,7 @@ QObjectPrivate::QObjectPrivate(int version)
     receiveChildEvents = true;
     postedEvents = 0;
     extraData = 0;
-    for (uint i = 0; i < (sizeof connectedSignals / sizeof connectedSignals[0]); ++i)
-        connectedSignals[i] = 0;
+    connectedSignals = 0;
     inEventHandler = false;
     inThreadChangeEvent = false;
     deleteWatch = 0;
@@ -2937,13 +2936,9 @@ bool QMetaObjectPrivate::connect(const QObject *sender, int signal_index,
 
     QObjectPrivate *const sender_d = QObjectPrivate::get(s);
     if (signal_index < 0) {
-        for (uint i = 0; i < (sizeof sender_d->connectedSignals
-                              / sizeof sender_d->connectedSignals[0] ); ++i)
-            sender_d->connectedSignals[i] = ~0u;
-    } else if (signal_index < (int)sizeof sender_d->connectedSignals * 8) {
-        uint n = (signal_index / (8 * sizeof sender_d->connectedSignals[0]));
-        sender_d->connectedSignals[n] |= (1 << (signal_index - n * 8
-                                    * sizeof sender_d->connectedSignals[0]));
+        sender_d->connectedSignals = ~ulong(0);
+    } else if (signal_index < (int)sizeof(sender_d->connectedSignals) * 8) {
+        sender_d->connectedSignals |= ulong(1) << signal_index;
     }
 
     return true;
@@ -3201,15 +3196,9 @@ void QMetaObject::activate(QObject *sender, const QMetaObject *m, int local_sign
     computeOffsets(m, &signalOffset, &methodOffset);
 
     int signal_index = signalOffset + local_signal_index;
-    if (signal_index < (int)sizeof(sender->d_func()->connectedSignals) * 8
-        && !qt_signal_spy_callback_set.signal_begin_callback
-        && !qt_signal_spy_callback_set.signal_end_callback) {
-        uint n = (signal_index / (8 * sizeof sender->d_func()->connectedSignals[0]));
-        uint m = 1 << (signal_index - n * 8 * sizeof sender->d_func()->connectedSignals[0]);
-        if ((sender->d_func()->connectedSignals[n] & m) == 0)
-            // nothing connected to these signals, and no spy
-            return;
-    }
+
+    if (!sender->d_func()->isSignalConnected(signal_index))
+        return; // nothing connected to these signals, and no spy
 
     if (sender->d_func()->blockSig)
         return;
@@ -3370,28 +3359,6 @@ int QObjectPrivate::signalIndex(const char *signalName) const
     return relative_index + signalOffset;
 }
 
-/*! \internal
-
-  Returns true if the signal with index \a signal_index from object \a sender is connected.
-  Signals with indices above a certain range are always considered connected (see connectedSignals
-  in QObjectPrivate). If a signal spy is installed, all signals are considered connected.
-
-  \a signal_index must be the index returned by QObjectPrivate::signalIndex;
-*/
-bool QObjectPrivate::isSignalConnected(int signal_index) const
-{
-    if (signal_index < (int)sizeof(connectedSignals) * 8
-        && !qt_signal_spy_callback_set.signal_begin_callback
-        && !qt_signal_spy_callback_set.signal_end_callback) {
-        uint n = (signal_index / (8 * sizeof connectedSignals[0]));
-        uint m = 1 << (signal_index - n * 8 * sizeof connectedSignals[0]);
-        if ((connectedSignals[n] & m) == 0)
-            // nothing connected to these signals, and no spy
-            return false;
-    }
-    return true;
-}
-
 /*****************************************************************************
   Properties
  *****************************************************************************/
diff --git a/src/corelib/kernel/qobject_p.h b/src/corelib/kernel/qobject_p.h
index f087407..f899c78 100644
--- a/src/corelib/kernel/qobject_p.h
+++ b/src/corelib/kernel/qobject_p.h
@@ -172,7 +172,7 @@ public:
     }
 
     int signalIndex(const char *signalName) const;
-    bool isSignalConnected(int signalIdx) const;
+    inline bool isSignalConnected(int signalIdx) const;
 
 public:
     QString objectName;
@@ -183,7 +183,7 @@ public:
 
     Connection *senders;     // linked list of connections connected to this object
     Sender *currentSender;   // object currently activating the object
-    mutable quint32 connectedSignals[2];   // 64-bit, so doesn't cause padding on 64-bit platforms
+    mutable ulong connectedSignals;
 
 #ifdef QT3_SUPPORT
     QList<QObject *> pendingChildInsertedEvents;
@@ -205,6 +205,23 @@ public:
     int *deleteWatch;
 };
 
+/*! \internal
+
+  Returns true if the signal with index \a signal_index from object \a sender is connected.
+  Signals with indices above a certain range are always considered connected (see connectedSignals
+  in QObjectPrivate). If a signal spy is installed, all signals are considered connected.
+
+  \a signal_index must be the index returned by QObjectPrivate::signalIndex;
+*/
+inline bool QObjectPrivate::isSignalConnected(int signal_index) const
+{
+    return signal_index >= (int)sizeof(connectedSignals) * 8
+        || qt_signal_spy_callback_set.signal_begin_callback
+        || qt_signal_spy_callback_set.signal_end_callback
+        || (connectedSignals & (ulong(1) << signal_index));
+}
+
+
 inline void q_guard_addGuard(QGuard<QObject> *g)
 {
     QObjectPrivate *p = QObjectPrivate::get(g->o);