De-duplicate vtables, part I: exported private classes

By making the destructor (usually the first non-inline, non-pure,
virtual function, and therefore the trigger for most compilers to
emit the vtable and type_info structures for the class in that TU)
out-of-line, vtables and, more importantly, type_info structures for
the class are pinned to a single TU. This prevents false negative
dynamic_cast and catch evaluation.

In this first batch, we de-inline destructors of exported private
classes.

Since they are already exported, users of these classes are unaffected
by the change, and since it's private API, we don't need to avoid
adding code to the out-of-line destructor until Qt 6.

Change-Id: I450707877d2cb6a77f79ae1dd355facb98d6c517
Reported-by: Volker Krause <volker.krause@kdab.com>
Task-number: QTBUG-45582
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/itemmodels/qabstractitemmodel.cpp

@@ -479,6 +479,11 @@ public:
 
 Q_GLOBAL_STATIC(QEmptyItemModel, qEmptyModel)
 
+
+QAbstractItemModelPrivate::~QAbstractItemModelPrivate()
+{
+}
+
 QAbstractItemModel *QAbstractItemModelPrivate::staticEmptyModel()
 {
     return qEmptyModel();

src/corelib/itemmodels/qabstractitemmodel_p.h

@@ -71,6 +71,8 @@ class Q_CORE_EXPORT QAbstractItemModelPrivate : public QObjectPrivate
 
 public:
     QAbstractItemModelPrivate() : QObjectPrivate(), supportedDragActions(-1), roleNames(defaultRoleNames()) {}
+    ~QAbstractItemModelPrivate();
+
     void removePersistentIndexData(QPersistentModelIndexData *data);
     void movePersistentIndexes(const QVector<QPersistentModelIndexData *> &indexes, int change, const QModelIndex &parent, Qt::Orientation orientation);
     void rowsAboutToBeInserted(const QModelIndex &parent, int first, int last);

src/corelib/kernel/qobject.cpp

@@ -65,6 +65,16 @@ QT_BEGIN_NAMESPACE
 
 static int DIRECT_CONNECTION_ONLY = 0;
 
+
+QDynamicMetaObjectData::~QDynamicMetaObjectData()
+{
+}
+
+QAbstractDynamicMetaObject::~QAbstractDynamicMetaObject()
+{
+}
+
+
 struct QSlotObjectBaseDeleter { // for use with QScopedPointer<QSlotObjectBase,...>
     static void cleanup(QtPrivate::QSlotObjectBase *slot) {
         if (slot) slot->destroyIfLastRef();

src/corelib/kernel/qobject_p.h

@@ -406,7 +406,7 @@ void Q_CORE_EXPORT qDeleteInEventHandler(QObject *o);
 struct QAbstractDynamicMetaObject;
 struct Q_CORE_EXPORT QDynamicMetaObjectData
 {
-    virtual ~QDynamicMetaObjectData() {}
+    virtual ~QDynamicMetaObjectData();
     virtual void objectDestroyed(QObject *) { delete this; }
 
     virtual QAbstractDynamicMetaObject *toDynamicMetaObject(QObject *) = 0;
@@ -415,6 +415,8 @@ struct Q_CORE_EXPORT QDynamicMetaObjectData
 
 struct Q_CORE_EXPORT QAbstractDynamicMetaObject : public QDynamicMetaObjectData, public QMetaObject
 {
+    ~QAbstractDynamicMetaObject();
+
     virtual QAbstractDynamicMetaObject *toDynamicMetaObject(QObject *) Q_DECL_OVERRIDE { return this; }
     virtual int createProperty(const char *, const char *) { return -1; }
     virtual int metaCall(QObject *, QMetaObject::Call c, int _id, void **a) Q_DECL_OVERRIDE

src/corelib/statemachine/qeventtransition.cpp

@@ -102,6 +102,10 @@ QEventTransitionPrivate::QEventTransitionPrivate()
     registered = false;
 }
 
+QEventTransitionPrivate::~QEventTransitionPrivate()
+{
+}
+
 QEventTransitionPrivate *QEventTransitionPrivate::get(QEventTransition *q)
 {
     return q->d_func();

src/corelib/statemachine/qeventtransition_p.h

@@ -55,6 +55,7 @@ class Q_CORE_EXPORT QEventTransitionPrivate : public QAbstractTransitionPrivate
     Q_DECLARE_PUBLIC(QEventTransition)
 public:
     QEventTransitionPrivate();
+    ~QEventTransitionPrivate();
 
     static QEventTransitionPrivate *get(QEventTransition *q);
 

src/gui/opengl/qopenglpaintdevice.cpp

@@ -169,6 +169,10 @@ QOpenGLPaintDevicePrivate::QOpenGLPaintDevicePrivate(const QSize &sz)
 {
 }
 
+QOpenGLPaintDevicePrivate::~QOpenGLPaintDevicePrivate()
+{
+}
+
 class QOpenGLEngineThreadStorage
 {
 public:

src/gui/opengl/qopenglpaintdevice_p.h

@@ -56,7 +56,7 @@ class Q_GUI_EXPORT QOpenGLPaintDevicePrivate
 {
 public:
     QOpenGLPaintDevicePrivate(const QSize &size);
-    virtual ~QOpenGLPaintDevicePrivate() { }
+    virtual ~QOpenGLPaintDevicePrivate();
 
     static QOpenGLPaintDevicePrivate *get(QOpenGLPaintDevice *dev) { return dev->d_func(); }
 

src/gui/painting/qpagedpaintdevice.cpp

@@ -36,6 +36,10 @@
 
 QT_BEGIN_NAMESPACE
 
+QPagedPaintDevicePrivate::~QPagedPaintDevicePrivate()
+{
+}
+
 /*!
     \class QPagedPaintDevice
     \inmodule QtGui

src/gui/painting/qpagedpaintdevice_p.h

@@ -61,9 +61,7 @@ public:
     {
     }
 
-    virtual ~QPagedPaintDevicePrivate()
-    {
-    }
+    virtual ~QPagedPaintDevicePrivate();
 
     // ### Qt6 Remove these and make public class methods virtual
     virtual bool setPageLayout(const QPageLayout &newPageLayout)

src/gui/painting/qpaintengine.cpp

@@ -968,6 +968,10 @@ QRect QPaintEngine::systemRect() const
     return d_func()->systemRect;
 }
 
+QPaintEnginePrivate::~QPaintEnginePrivate()
+{
+}
+
 void QPaintEnginePrivate::drawBoxTextItem(const QPointF &p, const QTextItemInt &ti)
 {
     if (!ti.glyphs.numGlyphs)

src/gui/painting/qpaintengine_p.h

@@ -60,7 +60,8 @@ class Q_GUI_EXPORT QPaintEnginePrivate
 public:
     QPaintEnginePrivate() : pdev(0), q_ptr(0), currentClipDevice(0), hasSystemTransform(0),
                             hasSystemViewport(0) {}
-    virtual ~QPaintEnginePrivate() { }
+    virtual ~QPaintEnginePrivate();
+
     QPaintDevice *pdev;
     QPaintEngine *q_ptr;
     QRegion systemClip;

src/widgets/effects/qgraphicseffect.cpp

@@ -111,6 +111,10 @@
 #ifndef QT_NO_GRAPHICSEFFECT
 QT_BEGIN_NAMESPACE
 
+QGraphicsEffectPrivate::~QGraphicsEffectPrivate()
+{
+}
+
 /*!
     \internal
     \class QGraphicsEffectSource

src/widgets/effects/qgraphicseffect_p.h

@@ -142,6 +142,7 @@ class Q_WIDGETS_EXPORT QGraphicsEffectPrivate : public QObjectPrivate
     Q_DECLARE_PUBLIC(QGraphicsEffect)
 public:
     QGraphicsEffectPrivate() : source(0), isEnabled(1) {}
+    ~QGraphicsEffectPrivate();
 
     inline void setGraphicsEffectSource(QGraphicsEffectSource *newSource)
     {

src/widgets/graphicsview/qgraphicsview.cpp

@@ -362,6 +362,10 @@ QGraphicsViewPrivate::QGraphicsViewPrivate()
     styleOptions.reserve(QGRAPHICSVIEW_PREALLOC_STYLE_OPTIONS);
 }
 
+QGraphicsViewPrivate::~QGraphicsViewPrivate()
+{
+}
+
 /*!
     \internal
 */

src/widgets/graphicsview/qgraphicsview_p.h

@@ -63,6 +63,7 @@ class Q_WIDGETS_EXPORT QGraphicsViewPrivate : public QAbstractScrollAreaPrivate
     Q_DECLARE_PUBLIC(QGraphicsView)
 public:
     QGraphicsViewPrivate();
+    ~QGraphicsViewPrivate();
 
     void recalculateContentSize();
     void centerView(QGraphicsView::ViewportAnchor anchor);