Short live Q_CONSTINIT!

It expands to the first available of

- constinit (C++20)
- [[clang::require_constant_initialization]] (Clang)
- __constinit (GCC >= 10)

Use it around the code (on and near static QBasicAtomic; this patch
makes no attempt to find all statics in qtbase).

[ChangeLog][QtCore][QtGlobal] Added macro Q_CONSTINIT.

Fixes: QTBUG-100484
Change-Id: I11e0363a7acb3464476859d12ec7f94319d82be7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/corelib/animation/qpropertyanimation.cpp

@@ -289,7 +289,7 @@ void QPropertyAnimation::updateState(QAbstractAnimation::State newState,
 
     QPropertyAnimation *animToStop = nullptr;
     {
-        static QBasicMutex mutex;
+        Q_CONSTINIT static QBasicMutex mutex;
         auto locker = qt_unique_lock(mutex);
         typedef QPair<QObject *, QByteArray> QPropertyAnimationPair;
         typedef QHash<QPropertyAnimationPair, QPropertyAnimation*> QPropertyAnimationHash;

src/corelib/animation/qvariantanimation.cpp

@@ -404,7 +404,7 @@ QBindable<QEasingCurve> QVariantAnimation::bindableEasingCurve()
 
 typedef QList<QVariantAnimation::Interpolator> QInterpolatorVector;
 Q_GLOBAL_STATIC(QInterpolatorVector, registeredInterpolators)
-static QBasicMutex registeredInterpolatorsMutex;
+Q_CONSTINIT static QBasicMutex registeredInterpolatorsMutex;
 
 /*!
     \fn template <typename T> void qRegisterAnimationInterpolator(QVariant (*func)(const T &from, const T &to, qreal progress))

src/corelib/global/qglobal.cpp

@@ -3344,7 +3344,7 @@ Q_CORE_EXPORT Q_DECL_CONST_FUNCTION unsigned int qt_int_sqrt(unsigned int n)
 
 // In the C runtime on all platforms access to the environment is not thread-safe. We
 // add thread-safety for the Qt wrappers.
-static QBasicMutex environmentMutex;
+Q_CONSTINIT static QBasicMutex environmentMutex;
 
 /*
   Wraps tzset(), which accesses the environment, so should only be called while
@@ -4114,6 +4114,33 @@ bool qunsetenv(const char *varName)
     \sa Q_LIKELY()
 */
 
+/*!
+    \macro Q_CONSTINIT
+    \relates <QtGlobal>
+    \since 6.4
+
+    \brief Enforces constant initialization when supported by the compiler.
+
+    If the compiler supports the C++20 \c{constinit} keyword, Clang's
+    \c{[[clang::require_constant_initialization]]} or GCC's \c{__constinit},
+    then this macro expands to the first one of these that is available,
+    otherwise it expands to nothing.
+
+    Variables marked as \c{constinit} cause a compile-error if their
+    initialization would have to be performed at runtime.
+
+    For constants, you can use \c{constexpr} since C++11, but \c{constexpr}
+    makes variables \c{const}, too, whereas \c{constinit} ensures constant
+    initialization, but doesn't make the variable \c{const}:
+
+    \table
+    \header \li Keyword       \li Added \li immutable \li constant-initialized
+    \row    \li \c{const}     \li C++98 \li yes       \li not required
+    \row    \li \c{constexpr} \li C++11 \li yes       \li required
+    \row    \li \c{constinit} \li C++20 \li no        \li required
+    \endtable
+*/
+
 /*!
     \macro QT_POINTER_SIZE
     \relates <QtGlobal>

src/corelib/global/qglobal.h

@@ -1165,6 +1165,16 @@ constexpr std::underlying_type_t<Enum> qToUnderlying(Enum e) noexcept
 #define Q_IMPLICIT
 #endif
 
+#ifdef __cpp_constinit
+# define Q_CONSTINIT constinit
+#elif defined(__has_cpp_attribute) && __has_cpp_attribute(clang::require_constant_initialization)
+# define Q_CONSTINIT [[clang::require_constant_initialization]]
+#elif defined(Q_CC_GNU) && Q_CC_GNU >= 1000
+# define Q_CONSTINIT __constinit
+#else
+# define Q_CONSTINIT
+#endif
+
 template <typename T> inline T *qGetPtrHelper(T *ptr) noexcept { return ptr; }
 template <typename Ptr> inline auto qGetPtrHelper(Ptr &ptr) noexcept -> decltype(ptr.get())
 { static_assert(noexcept(ptr.get()), "Smart d pointers for Q_DECLARE_PRIVATE must have noexcept get()"); return ptr.get(); }

src/corelib/global/qglobalstatic.h

@@ -63,7 +63,7 @@ template <typename QGS> union Holder
     using PlainType = std::remove_cv_t<Type>;
 
     static constexpr bool ConstructionIsNoexcept = noexcept(QGS::innerFunction(nullptr));
-    static inline QBasicAtomicInteger<qint8> guard = { QtGlobalStatic::Uninitialized };
+    Q_CONSTINIT static inline QBasicAtomicInteger<qint8> guard = { QtGlobalStatic::Uninitialized };
 
     // union's sole member
     PlainType storage;
@@ -144,7 +144,7 @@ protected:
             new (pointer) QGS_Type ARGS;                                    \
         }                                                                   \
     }; }                                                                    \
-    static QGlobalStatic<QtGlobalStatic::Holder<Q_QGS_ ## NAME>> NAME;      \
+    Q_CONSTINIT static QGlobalStatic<QtGlobalStatic::Holder<Q_QGS_ ## NAME>> NAME; \
     QT_WARNING_POP
     /**/
 

src/corelib/global/qlogging.cpp

@@ -1096,7 +1096,7 @@ struct QMessagePattern
 Q_DECLARE_TYPEINFO(QMessagePattern::BacktraceParams, Q_RELOCATABLE_TYPE);
 #endif
 
-QBasicMutex QMessagePattern::mutex;
+Q_CONSTINIT QBasicMutex QMessagePattern::mutex;
 
 QMessagePattern::QMessagePattern()
 {
@@ -1750,7 +1750,7 @@ static bool android_default_message_handler(QtMsgType type,
 static void win_outputDebugString_helper(const QString &message)
 {
     const qsizetype maxOutputStringLength = 32766;
-    static QBasicMutex m;
+    Q_CONSTINIT static QBasicMutex m;
     auto locker = qt_unique_lock(m);
     // fast path: Avoid string copies if one output is enough
     if (message.length() <= maxOutputStringLength) {
@@ -1827,7 +1827,7 @@ static void stderr_message_handler(QtMsgType type, const QMessageLogContext &con
 #ifdef Q_OS_WASM
     // Prevent thread cross-talk, which causes Emscripten to log
     // non-valid UTF-8. FIXME: remove once we upgrade to emsdk > 2.0.30
-    static QBasicMutex m;
+    Q_CONSTINIT static QBasicMutex m;
     auto locker = qt_unique_lock(m);
 #endif
 

src/corelib/io/qfileselector.cpp

@@ -58,7 +58,7 @@ using namespace Qt::StringLiterals;
 static const char env_override[] = "QT_NO_BUILTIN_SELECTORS";
 
 Q_GLOBAL_STATIC(QFileSelectorSharedData, sharedData);
-static QBasicMutex sharedDataMutex;
+Q_CONSTINIT static QBasicMutex sharedDataMutex;
 
 QFileSelectorPrivate::QFileSelectorPrivate()
     : QObjectPrivate()

src/corelib/io/qprocess_unix.cpp

@@ -424,7 +424,7 @@ static QString resolveExecutable(const QString &program)
         {
             // CFBundle is not reentrant, since CFBundleCreate might return a reference
             // to a cached bundle object. Protect the bundle calls with a mutex lock.
-            static QBasicMutex cfbundleMutex;
+            Q_CONSTINIT static QBasicMutex cfbundleMutex;
             const auto locker = qt_scoped_lock(cfbundleMutex);
             QCFType<CFBundleRef> bundle = CFBundleCreate(0, url);
             // 'executableURL' can be either relative or absolute ...

src/corelib/io/qsettings.cpp

@@ -132,7 +132,7 @@ Q_GLOBAL_STATIC(ConfFileCache, unusedCacheFunc)
 Q_GLOBAL_STATIC(PathHash, pathHashFunc)
 Q_GLOBAL_STATIC(CustomFormatVector, customFormatVectorFunc)
 
-static QBasicMutex settingsGlobalMutex;
+Q_CONSTINIT static QBasicMutex settingsGlobalMutex;
 
 static QSettings::Format globalDefaultFormat = QSettings::NativeFormat;
 

src/corelib/kernel/qcoreapplication.cpp

@@ -265,8 +265,8 @@ typedef QList<QtStartUpFunction> QStartUpFuncList;
 Q_GLOBAL_STATIC(QStartUpFuncList, preRList)
 typedef QList<QtCleanUpFunction> QVFuncList;
 Q_GLOBAL_STATIC(QVFuncList, postRList)
-static QBasicMutex globalRoutinesMutex;
-static bool preRoutinesCalled = false;
+Q_CONSTINIT static QBasicMutex globalRoutinesMutex;
+Q_CONSTINIT static bool preRoutinesCalled = false;
 
 /*!
     \internal

src/corelib/kernel/qeventdispatcher_glib.cpp

@@ -296,7 +296,7 @@ QEventDispatcherGlibPrivate::QEventDispatcherGlibPrivate(GMainContext *context)
 {
 #if GLIB_MAJOR_VERSION == 2 && GLIB_MINOR_VERSION < 32
     if (qEnvironmentVariableIsEmpty("QT_NO_THREADED_GLIB")) {
-        static QBasicMutex mutex;
+        Q_CONSTINIT static QBasicMutex mutex;
         QMutexLocker locker(&mutex);
         if (!g_thread_supported())
             g_thread_init(NULL);

src/corelib/kernel/qobject.cpp

@@ -149,7 +149,7 @@ static int *queuedConnectionTypes(const QArgumentType *argumentTypes, int argc)
     return types.release();
 }
 
-static QBasicMutex _q_ObjectMutexPool[131];
+Q_CONSTINIT static QBasicMutex _q_ObjectMutexPool[131];
 
 /**
  * \internal

src/corelib/plugin/qlibrary.cpp

@@ -354,9 +354,9 @@ private:
     LibraryMap libraryMap;
 };
 
-static QBasicMutex qt_library_mutex;
-static QLibraryStore *qt_library_data = nullptr;
-static bool qt_library_data_once;
+Q_CONSTINIT static QBasicMutex qt_library_mutex;
+Q_CONSTINIT static QLibraryStore *qt_library_data = nullptr;
+Q_CONSTINIT static bool qt_library_data_once;
 
 QLibraryStore::~QLibraryStore()
 {

src/corelib/text/qlocale.cpp

@@ -792,7 +792,7 @@ static const QLocaleData *systemData()
       one thread.
     */
     {
-        static QBasicMutex systemDataMutex;
+        Q_CONSTINIT static QBasicMutex systemDataMutex;
         systemDataMutex.lock();
         if (systemLocaleData.m_language_id == 0)
             updateSystemPrivate();

src/corelib/thread/qthreadpool.cpp

@@ -501,8 +501,8 @@ QThreadPool::~QThreadPool()
 */
 QThreadPool *QThreadPool::globalInstance()
 {
-    static QPointer<QThreadPool> theInstance;
-    static QBasicMutex theMutex;
+    Q_CONSTINIT static QPointer<QThreadPool> theInstance;
+    Q_CONSTINIT static QBasicMutex theMutex;
 
     const QMutexLocker locker(&theMutex);
     if (theInstance.isNull() && !QCoreApplication::closingDown())

src/corelib/thread/qthreadstorage.cpp

@@ -68,7 +68,7 @@ void qtsDebug(const char *fmt, ...)
 #  define DEBUG_MSG if (false)qDebug
 #endif
 
-static QBasicMutex destructorsMutex;
+Q_CONSTINIT static QBasicMutex destructorsMutex;
 typedef QList<void (*)(void *)> DestructorMap;
 Q_GLOBAL_STATIC(DestructorMap, destructors)
 

src/corelib/time/qtimezoneprivate_tz.cpp

@@ -67,7 +67,7 @@ QT_BEGIN_NAMESPACE
 using namespace Qt::StringLiterals;
 
 #if QT_CONFIG(icu)
-static QBasicMutex s_icu_mutex;
+Q_CONSTINIT static QBasicMutex s_icu_mutex;
 #endif
 
 /*

src/dbus/qdbus_symbols.cpp

@@ -79,8 +79,8 @@ bool qdbus_loadLibDBus()
         return false;
 #endif
 
-    static bool triedToLoadLibrary = false;
-    static QBasicMutex mutex;
+    Q_CONSTINIT static bool triedToLoadLibrary = false;
+    Q_CONSTINIT static QBasicMutex mutex;
     const auto locker = qt_scoped_lock(mutex);
 
     QLibrary *&lib = qdbus_libdbus;

src/dbus/qdbusintegrator.cpp

@@ -1991,14 +1991,14 @@ public:
 #if defined(QT_NO_DEBUG)
         // when in a release build, we default these to off.
         // this means that we only affect code that explicitly enables the warning.
-        static int mainThreadWarningAmount = -1;
-        static int otherThreadWarningAmount = -1;
+        Q_CONSTINIT static int mainThreadWarningAmount = -1;
+        Q_CONSTINIT static int otherThreadWarningAmount = -1;
 #else
-        static int mainThreadWarningAmount = 200;
-        static int otherThreadWarningAmount = 500;
+        Q_CONSTINIT static int mainThreadWarningAmount = 200;
+        Q_CONSTINIT static int otherThreadWarningAmount = 500;
 #endif
-        static bool initializedAmounts = false;
-        static QBasicMutex initializeMutex;
+        Q_CONSTINIT static bool initializedAmounts = false;
+        Q_CONSTINIT static QBasicMutex initializeMutex;
         auto locker = qt_unique_lock(initializeMutex);
 
         if (!initializedAmounts) {

src/dbus/qdbusmetaobject.cpp

@@ -144,8 +144,8 @@ static int registerComplexDBusType(const QByteArray &typeName)
         {}
     };
 
-    static QBasicMutex mutex;
-    static struct Hash : QHash<QByteArray, QMetaType>
+    Q_CONSTINIT static QBasicMutex mutex;
+    Q_CONSTINIT static struct Hash : QHash<QByteArray, QMetaType>
     {
         ~Hash()
         {

src/gui/image/qimagereader.cpp

@@ -186,7 +186,7 @@ static QImageIOHandler *createReadHandlerHelper(QIODevice *device,
     QByteArray suffix;
 
 #ifndef QT_NO_IMAGEFORMATPLUGIN
-    static QBasicMutex mutex;
+    Q_CONSTINIT static QBasicMutex mutex;
     const auto locker = qt_scoped_lock(mutex);
 
     typedef QMultiMap<int, QString> PluginKeyMap;

src/gui/kernel/qguiapplication.cpp

@@ -145,79 +145,79 @@ QT_BEGIN_NAMESPACE
 Q_CORE_EXPORT void qt_call_post_routines();
 Q_GUI_EXPORT bool qt_is_tty_app = false;
 
-Qt::MouseButtons QGuiApplicationPrivate::mouse_buttons = Qt::NoButton;
-Qt::KeyboardModifiers QGuiApplicationPrivate::modifier_buttons = Qt::NoModifier;
+Q_CONSTINIT Qt::MouseButtons QGuiApplicationPrivate::mouse_buttons = Qt::NoButton;
+Q_CONSTINIT Qt::KeyboardModifiers QGuiApplicationPrivate::modifier_buttons = Qt::NoModifier;
 
-QGuiApplicationPrivate::QLastCursorPosition QGuiApplicationPrivate::lastCursorPosition;
+Q_CONSTINIT QGuiApplicationPrivate::QLastCursorPosition QGuiApplicationPrivate::lastCursorPosition;
 
-QWindow *QGuiApplicationPrivate::currentMouseWindow = nullptr;
+Q_CONSTINIT QWindow *QGuiApplicationPrivate::currentMouseWindow = nullptr;
 
-QString QGuiApplicationPrivate::styleOverride;
+Q_CONSTINIT QString QGuiApplicationPrivate::styleOverride;
 
-Qt::ApplicationState QGuiApplicationPrivate::applicationState = Qt::ApplicationInactive;
+Q_CONSTINIT Qt::ApplicationState QGuiApplicationPrivate::applicationState = Qt::ApplicationInactive;
 
-Qt::HighDpiScaleFactorRoundingPolicy QGuiApplicationPrivate::highDpiScaleFactorRoundingPolicy =
+Q_CONSTINIT Qt::HighDpiScaleFactorRoundingPolicy QGuiApplicationPrivate::highDpiScaleFactorRoundingPolicy =
     Qt::HighDpiScaleFactorRoundingPolicy::PassThrough;
 
-QPointer<QWindow> QGuiApplicationPrivate::currentDragWindow;
+Q_CONSTINIT QPointer<QWindow> QGuiApplicationPrivate::currentDragWindow;
 
-QList<QGuiApplicationPrivate::TabletPointData> QGuiApplicationPrivate::tabletDevicePoints; // TODO remove
+Q_CONSTINIT QList<QGuiApplicationPrivate::TabletPointData> QGuiApplicationPrivate::tabletDevicePoints; // TODO remove
 
-QPlatformIntegration *QGuiApplicationPrivate::platform_integration = nullptr;
-QPlatformTheme *QGuiApplicationPrivate::platform_theme = nullptr;
+Q_CONSTINIT QPlatformIntegration *QGuiApplicationPrivate::platform_integration = nullptr;
+Q_CONSTINIT QPlatformTheme *QGuiApplicationPrivate::platform_theme = nullptr;
 
-QList<QObject *> QGuiApplicationPrivate::generic_plugin_list;
+Q_CONSTINIT QList<QObject *> QGuiApplicationPrivate::generic_plugin_list;
 
 enum ApplicationResourceFlags
 {
     ApplicationFontExplicitlySet = 0x2
 };
 
-static unsigned applicationResourceFlags = 0;
+Q_CONSTINIT static unsigned applicationResourceFlags = 0;
 
-QIcon *QGuiApplicationPrivate::app_icon = nullptr;
+Q_CONSTINIT QIcon *QGuiApplicationPrivate::app_icon = nullptr;
 
-QString *QGuiApplicationPrivate::platform_name = nullptr;
-QString *QGuiApplicationPrivate::displayName = nullptr;
-QString *QGuiApplicationPrivate::desktopFileName = nullptr;
+Q_CONSTINIT QString *QGuiApplicationPrivate::platform_name = nullptr;
+Q_CONSTINIT QString *QGuiApplicationPrivate::displayName = nullptr;
+Q_CONSTINIT QString *QGuiApplicationPrivate::desktopFileName = nullptr;
 
-QPalette *QGuiApplicationPrivate::app_pal = nullptr;        // default application palette
+Q_CONSTINIT QPalette *QGuiApplicationPrivate::app_pal = nullptr;        // default application palette
 
-Qt::MouseButton QGuiApplicationPrivate::mousePressButton = Qt::NoButton;
+Q_CONSTINIT Qt::MouseButton QGuiApplicationPrivate::mousePressButton = Qt::NoButton;
 
-static int mouseDoubleClickDistance = 0;
-static int touchDoubleTapDistance = 0;
+Q_CONSTINIT static int mouseDoubleClickDistance = 0;
+Q_CONSTINIT static int touchDoubleTapDistance = 0;
 
-QWindow *QGuiApplicationPrivate::currentMousePressWindow = nullptr;
+Q_CONSTINIT QWindow *QGuiApplicationPrivate::currentMousePressWindow = nullptr;
 
-static Qt::LayoutDirection layout_direction = Qt::LayoutDirectionAuto;
-static Qt::LayoutDirection effective_layout_direction = Qt::LeftToRight;
-static bool force_reverse = false;
+Q_CONSTINIT static Qt::LayoutDirection layout_direction = Qt::LayoutDirectionAuto;
+Q_CONSTINIT static Qt::LayoutDirection effective_layout_direction = Qt::LeftToRight;
+Q_CONSTINIT static bool force_reverse = false;
 
-QGuiApplicationPrivate *QGuiApplicationPrivate::self = nullptr;
-int QGuiApplicationPrivate::m_fakeMouseSourcePointId = -1;
+Q_CONSTINIT QGuiApplicationPrivate *QGuiApplicationPrivate::self = nullptr;
+Q_CONSTINIT int QGuiApplicationPrivate::m_fakeMouseSourcePointId = -1;
 
 #ifndef QT_NO_CLIPBOARD
-QClipboard *QGuiApplicationPrivate::qt_clipboard = nullptr;
+Q_CONSTINIT QClipboard *QGuiApplicationPrivate::qt_clipboard = nullptr;
 #endif
 
-QList<QScreen *> QGuiApplicationPrivate::screen_list;
+Q_CONSTINIT QList<QScreen *> QGuiApplicationPrivate::screen_list;
 
-QWindowList QGuiApplicationPrivate::window_list;
-QWindow *QGuiApplicationPrivate::focus_window = nullptr;
+Q_CONSTINIT QWindowList QGuiApplicationPrivate::window_list;
+Q_CONSTINIT QWindow *QGuiApplicationPrivate::focus_window = nullptr;
 
-static QBasicMutex applicationFontMutex;
-QFont *QGuiApplicationPrivate::app_font = nullptr;
-QStyleHints *QGuiApplicationPrivate::styleHints = nullptr;
-bool QGuiApplicationPrivate::obey_desktop_settings = true;
+Q_CONSTINIT static QBasicMutex applicationFontMutex;
+Q_CONSTINIT QFont *QGuiApplicationPrivate::app_font = nullptr;
+Q_CONSTINIT QStyleHints *QGuiApplicationPrivate::styleHints = nullptr;
+Q_CONSTINIT bool QGuiApplicationPrivate::obey_desktop_settings = true;
 
-QInputDeviceManager *QGuiApplicationPrivate::m_inputDeviceManager = nullptr;
+Q_CONSTINIT QInputDeviceManager *QGuiApplicationPrivate::m_inputDeviceManager = nullptr;
 
-qreal QGuiApplicationPrivate::m_maxDevicePixelRatio = 0.0;
+Q_CONSTINIT qreal QGuiApplicationPrivate::m_maxDevicePixelRatio = 0.0;
 
-static qreal fontSmoothingGamma = 1.7;
+Q_CONSTINIT static qreal fontSmoothingGamma = 1.7;
 
-bool QGuiApplicationPrivate::quitOnLastWindowClosed = true;
+Q_CONSTINIT bool QGuiApplicationPrivate::quitOnLastWindowClosed = true;
 
 extern void qRegisterGuiVariant();
 #if QT_CONFIG(animation)

src/gui/kernel/qinputdevice.cpp

@@ -264,7 +264,7 @@ QString QInputDevice::seatName() const
 
 using InputDevicesList = QList<const QInputDevice *>;
 Q_GLOBAL_STATIC(InputDevicesList, deviceList)
-static QBasicMutex devicesMutex;
+Q_CONSTINIT static QBasicMutex devicesMutex;
 
 /*!
     Returns a list of all registered input devices (keyboards and pointing devices).

src/gui/painting/qcolorspace.cpp

@@ -54,7 +54,7 @@
 
 QT_BEGIN_NAMESPACE
 
-QBasicMutex QColorSpacePrivate::s_lutWriteLock;
+Q_CONSTINIT QBasicMutex QColorSpacePrivate::s_lutWriteLock;
 
 static QAtomicPointer<QColorSpacePrivate> s_predefinedColorspacePrivates[QColorSpace::ProPhotoRgb] = {};
 static void cleanupPredefinedColorspaces()

src/network/access/qnetworkaccessmanager.cpp

@@ -1714,7 +1714,7 @@ QNetworkRequest QNetworkAccessManagerPrivate::prepareMultipart(const QNetworkReq
 */
 void QNetworkAccessManagerPrivate::ensureBackendPluginsLoaded()
 {
-    static QBasicMutex mutex;
+    Q_CONSTINIT static QBasicMutex mutex;
     std::unique_lock locker(mutex);
     if (!loader())
         return;

src/network/kernel/qauthenticator.cpp

@@ -1574,7 +1574,7 @@ static PSecurityFunctionTableW pSecurityFunctionTable = nullptr;
 
 static bool q_SSPI_library_load()
 {
-    static QBasicMutex mutex;
+    Q_CONSTINIT static QBasicMutex mutex;
     QMutexLocker l(&mutex);
 
     if (pSecurityFunctionTable == nullptr)

src/network/kernel/qnetworkinformation.cpp

@@ -124,7 +124,7 @@ bool QNetworkInformationPrivate::initializeList()
         return false;
     if (!dataHolder())
         return false;
-    static QBasicMutex mutex;
+    Q_CONSTINIT static QBasicMutex mutex;
     QMutexLocker initLocker(&mutex);
 
 #if QT_CONFIG(library)

src/network/ssl/qtlsbackend.cpp

@@ -91,7 +91,7 @@ public:
         if (!loader())
             return false;
 
-        static QBasicMutex mutex;
+        Q_CONSTINIT static QBasicMutex mutex;
         const QMutexLocker locker(&mutex);
         if (backends.size())
             return true;

src/plugins/platforms/xcb/qxcbeventqueue.cpp

@@ -47,8 +47,8 @@
 
 QT_BEGIN_NAMESPACE
 
-static QBasicMutex qAppExiting;
-static bool dispatcherOwnerDestructing = false;
+Q_CONSTINIT static QBasicMutex qAppExiting;
+Q_CONSTINIT static bool dispatcherOwnerDestructing = false;
 
 /*!
     \class QXcbEventQueue

src/plugins/tls/openssl/qsslsocket_openssl_symbols.cpp

@@ -868,9 +868,9 @@ static LoadedOpenSsl loadOpenSsl()
 }
 #endif
 
-static QBasicMutex symbolResolveMutex;
-static QBasicAtomicInt symbolsResolved = Q_BASIC_ATOMIC_INITIALIZER(false);
-static bool triedToResolveSymbols = false;
+Q_CONSTINIT static QBasicMutex symbolResolveMutex;
+Q_CONSTINIT static QBasicAtomicInt symbolsResolved = Q_BASIC_ATOMIC_INITIALIZER(false);
+Q_CONSTINIT static bool triedToResolveSymbols = false;
 
 bool q_resolveOpenSslSymbols()
 {