2 files changed, 23 insertions, 38 deletions

diff --git a/src/corelib/kernel/qcoreevent.cpp b/src/corelib/kernel/qcoreevent.cpp
index 847f3227ea..86d43d2d96 100644
--- a/src/corelib/kernel/qcoreevent.cpp
+++ b/src/corelib/kernel/qcoreevent.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Copyright (C) 2016 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
@@ -295,9 +295,8 @@ QT_BEGIN_NAMESPACE
     Contructs an event object of type \a type.
 */
 QEvent::QEvent(Type type)
-    : d(nullptr), t(type), m_posted(false), m_spont(false), m_accept(true),
-      m_inputEvent(false), m_pointerEvent(false), m_singlePointEvent(false),
-      m_reserved(0)
+    : t(type), m_reserved(0),
+      m_inputEvent(false), m_pointerEvent(false), m_singlePointEvent(false)
 {
     Q_TRACE(QEvent_ctor, this, t);
 }
@@ -306,17 +305,7 @@ QEvent::QEvent(Type type)
     \internal
     Copies the \a other event.
 */
-QEvent::QEvent(const QEvent &other)
-    : d(other.d), t(other.t), m_posted(other.m_posted), m_spont(other.m_spont),
-      m_accept(other.m_accept), m_inputEvent(other.m_inputEvent),
-      m_pointerEvent(other.m_pointerEvent), m_singlePointEvent(other.m_singlePointEvent),
-      m_reserved(other.m_reserved)
-{
-    Q_TRACE(QEvent_ctor, this, t);
-    // if QEventPrivate becomes available, make sure to implement a
-    // virtual QEventPrivate *clone() const; function so we can copy here
-    Q_ASSERT_X(!d, "QEvent", "Impossible, this can't happen: QEventPrivate isn't defined anywhere");
-}
+QEvent::QEvent(const QEvent &other) = default;
 
 /*!
     \internal
@@ -351,18 +340,7 @@ QEvent::QEvent(const QEvent &other)
     Copying events is a bad idea, yet some Qt 4 code does it (notably,
     QApplication and the state machine).
  */
-QEvent &QEvent::operator=(const QEvent &other)
-{
-    // if QEventPrivate becomes available, make sure to implement a
-    // virtual QEventPrivate *clone() const; function so we can copy here
-    Q_ASSERT_X(!other.d, "QEvent", "Impossible, this can't happen: QEventPrivate isn't defined anywhere");
-
-    t = other.t;
-    m_posted = other.m_posted;
-    m_spont = other.m_spont;
-    m_accept = other.m_accept;
-    return *this;
-}
+QEvent &QEvent::operator=(const QEvent &other) = default;
 
 /*!
     Destroys the event. If it was \l{QCoreApplication::postEvent()}{posted},
diff --git a/src/corelib/kernel/qcoreevent.h b/src/corelib/kernel/qcoreevent.h
index dbca4adaab..cfaa959dec 100644
--- a/src/corelib/kernel/qcoreevent.h
+++ b/src/corelib/kernel/qcoreevent.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -320,27 +320,34 @@ protected:
     QEvent(Type type, PointerEventTag) : QEvent(type, InputEventTag{}) { m_pointerEvent = true; }
     struct SinglePointEventTag { explicit SinglePointEventTag() = default; };
     QEvent(Type type, SinglePointEventTag) : QEvent(type, PointerEventTag{}) { m_singlePointEvent = true; }
-    QEventPrivate *d;
+    QEventPrivate *d = nullptr;
     quint16 t;
 
 private:
-    quint16 m_posted : 1;
-    quint16 m_spont : 1;
-    quint16 m_accept : 1;
+    /*
+        We can assume that C++ types are 8-byte aligned, and we can't assume that compilers
+        coalesce data members from subclasses. Use bitfields to fill up to next 8-byte
+        aligned size, which is 24 bytes. That way we don't waste memory, and have plenty of room
+        for future flags.
+        Don't use bitfields for the most important flags, as that would generate more code, and
+        access is always inline. Bytes used are:
+        8 vptr + 8 d-pointer + 2 type + 3 bool flags => 3 bytes left, so 24 bits. However,
+        compiler will add padding after the booleans, so add another unused bool, which leaves
+        us with 16 bits.
+    */
+    bool m_posted = false;
+    bool m_spont = false;
+    bool m_accept = true;
+    bool m_unused = false;
+    quint16 m_reserved : 13;
     quint16 m_inputEvent : 1;
     quint16 m_pointerEvent : 1;
     quint16 m_singlePointEvent : 1;
-    quint16 m_reserved : 10;
 
     friend class QCoreApplication;
     friend class QCoreApplicationPrivate;
     friend class QThreadData;
     friend class QApplication;
-#if QT_CONFIG(shortcut)
-    friend class QShortcutMap;
-#endif
-    friend class QGraphicsView;
-    friend class QGraphicsScene;
     friend class QGraphicsScenePrivate;
     // from QtTest:
     friend class QSpontaneKeyEvent;