Make some atomic counters zero-based

A variable of static storage duration that is not zero-initialized
takes up space in the DATA segment of the executable. By making the
counters start at zero and adding the initial value afterwards, we
move them over to the BSS segment, which does not take up space in
the executable.

Wrap atomics used across function boundaries into small functions,
to avoid code duplication and to increase readability.

Change-Id: Ida6ed316ecb8fe20da62a9577161349e14de5aed
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/plugin/quuid.cpp

@@ -968,10 +968,10 @@ QUuid QUuid::createUuid()
         if (!uuidseed.hasLocalData())
         {
             int *pseed = new int;
-            static QBasicAtomicInt serial = Q_BASIC_ATOMIC_INITIALIZER(2);
+            static QBasicAtomicInt serial;
             qsrand(*pseed = QDateTime::currentSecsSinceEpoch()
                    + quintptr(&pseed)
-                   + serial.fetchAndAddRelaxed(1));
+                   + 2 + serial.fetchAndAddRelaxed(1));
             uuidseed.setLocalData(pseed);
         }
 #else

src/gui/image/qicon.cpp

@@ -97,7 +97,11 @@ QT_BEGIN_NAMESPACE
   \value On  Display the pixmap when the widget is in an "on" state
 */
 
-static QBasicAtomicInt serialNumCounter = Q_BASIC_ATOMIC_INITIALIZER(1);
+static int nextSerialNumCounter()
+{
+    static QBasicAtomicInt serial;
+    return 1 + serial.fetchAndAddRelaxed(1);
+}
 
 static void qt_cleanup_icon_cache();
 namespace {
@@ -139,7 +143,7 @@ static qreal qt_effective_device_pixel_ratio(QWindow *window = 0)
 
 QIconPrivate::QIconPrivate(QIconEngine *e)
     : engine(e), ref(1),
-    serialNum(serialNumCounter.fetchAndAddRelaxed(1)),
+      serialNum(nextSerialNumCounter()),
     detach_no(0),
     is_mask(false)
 {

src/gui/image/qimage.cpp

@@ -89,12 +89,16 @@ static QImage rotated90(const QImage &src);
 static QImage rotated180(const QImage &src);
 static QImage rotated270(const QImage &src);
 
-QBasicAtomicInt qimage_serial_number = Q_BASIC_ATOMIC_INITIALIZER(1);
+static int next_qimage_serial_number()
+{
+    static QBasicAtomicInt serial;
+    return 1 + serial.fetchAndAddRelaxed(1);
+}
 
 QImageData::QImageData()
     : ref(0), width(0), height(0), depth(0), nbytes(0), devicePixelRatio(1.0), data(0),
       format(QImage::Format_ARGB32), bytes_per_line(0),
-      ser_no(qimage_serial_number.fetchAndAddRelaxed(1)),
+      ser_no(next_qimage_serial_number()),
       detach_no(0),
       dpmx(qt_defaultDpiX() * 100 / qreal(2.54)),
       dpmy(qt_defaultDpiY() * 100 / qreal(2.54)),

src/gui/opengl/qopengltextureglyphcache.cpp

@@ -47,7 +47,11 @@
 QT_BEGIN_NAMESPACE
 
 
-QBasicAtomicInt qopengltextureglyphcache_serial_number = Q_BASIC_ATOMIC_INITIALIZER(1);
+static int next_qopengltextureglyphcache_serial_number()
+{
+    static QBasicAtomicInt serial;
+    return 1 + serial.fetchAndAddRelaxed(1);
+}
 
 QOpenGLTextureGlyphCache::QOpenGLTextureGlyphCache(QFontEngine::GlyphFormat format, const QTransform &matrix)
     : QImageTextureGlyphCache(format, matrix)
@@ -55,7 +59,7 @@ QOpenGLTextureGlyphCache::QOpenGLTextureGlyphCache(QFontEngine::GlyphFormat form
     , pex(0)
     , m_blitProgram(0)
     , m_filterMode(Nearest)
-    , m_serialNumber(qopengltextureglyphcache_serial_number.fetchAndAddRelaxed(1))
+    , m_serialNumber(next_qopengltextureglyphcache_serial_number())
     , m_buffer(QOpenGLBuffer::VertexBuffer)
 {
 #ifdef QT_GL_TEXTURE_GLYPH_CACHE_DEBUG

src/network/access/qftp.cpp

@@ -246,22 +246,25 @@ public:
     } data;
     bool is_ba;
 
-    static QBasicAtomicInt idCounter;
 };
 
-QBasicAtomicInt QFtpCommand::idCounter = Q_BASIC_ATOMIC_INITIALIZER(1);
+static int nextId()
+{
+    static QBasicAtomicInt counter;
+    return 1 + counter.fetchAndAddRelaxed(1);
+}
 
 QFtpCommand::QFtpCommand(QFtp::Command cmd, const QStringList &raw, const QByteArray &ba)
     : command(cmd), rawCmds(raw), is_ba(true)
 {
-    id = idCounter.fetchAndAddRelaxed(1);
+    id = nextId();
     data.ba = new QByteArray(ba);
 }
 
 QFtpCommand::QFtpCommand(QFtp::Command cmd, const QStringList &raw, QIODevice *dev)
     : command(cmd), rawCmds(raw), is_ba(false)
 {
-    id = idCounter.fetchAndAddRelaxed(1);
+    id = nextId();
     data.dev = dev;
 }
 

src/network/kernel/qhostinfo.cpp

@@ -183,7 +183,11 @@ void emit_results_ready(const QHostInfo &hostInfo, const QObject *receiver,
     \sa QAbstractSocket, {http://www.rfc-editor.org/rfc/rfc3492.txt}{RFC 3492}
 */
 
-static QBasicAtomicInt theIdCounter = Q_BASIC_ATOMIC_INITIALIZER(1);
+static int nextId()
+{
+    static QBasicAtomicInt counter;
+    return 1 + counter.fetchAndAddRelaxed(1);
+}
 
 /*!
     Looks up the IP address(es) associated with host name \a name, and
@@ -229,7 +233,7 @@ int QHostInfo::lookupHost(const QString &name, QObject *receiver,
 
     qRegisterMetaType<QHostInfo>();
 
-    int id = theIdCounter.fetchAndAddRelaxed(1); // generate unique ID
+    int id = nextId(); // generate unique ID
 
     if (name.isEmpty()) {
         if (!receiver)
@@ -596,7 +600,7 @@ int QHostInfo::lookupHostImpl(const QString &name,
 
     qRegisterMetaType<QHostInfo>();
 
-    int id = theIdCounter.fetchAndAddRelaxed(1); // generate unique ID
+    int id = nextId(); // generate unique ID
 
     if (Q_UNLIKELY(name.isEmpty())) {
         QHostInfo hostInfo(id);

src/network/socket/qsocks5socketengine.cpp

@@ -1002,13 +1002,17 @@ QSocks5SocketEngine::~QSocks5SocketEngine()
         delete d->bindData;
 }
 
-static QBasicAtomicInt descriptorCounter = Q_BASIC_ATOMIC_INITIALIZER(1);
+static int nextDescriptor()
+{
+    static QBasicAtomicInt counter;
+    return 1 + counter.fetchAndAddRelaxed(1);
+}
 
 bool QSocks5SocketEngine::initialize(QAbstractSocket::SocketType type, QAbstractSocket::NetworkLayerProtocol protocol)
 {
     Q_D(QSocks5SocketEngine);
 
-    d->socketDescriptor = descriptorCounter.fetchAndAddRelaxed(1);
+    d->socketDescriptor = nextDescriptor();
 
     d->socketType = type;
     d->socketProtocol = protocol;

src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp

@@ -45,7 +45,11 @@
 QT_BEGIN_NAMESPACE
 
 
-QBasicAtomicInt qgltextureglyphcache_serial_number = Q_BASIC_ATOMIC_INITIALIZER(1);
+static int next_qgltextureglyphcache_serial_number()
+{
+    static QBasicAtomicInt serial;
+    return 1 + serial.fetchAndAddRelaxed(1);
+}
 
 QGLTextureGlyphCache::QGLTextureGlyphCache(QFontEngine::GlyphFormat format, const QTransform &matrix)
     : QImageTextureGlyphCache(format, matrix)
@@ -53,7 +57,7 @@ QGLTextureGlyphCache::QGLTextureGlyphCache(QFontEngine::GlyphFormat format, cons
     , pex(0)
     , m_blitProgram(0)
     , m_filterMode(Nearest)
-    , m_serialNumber(qgltextureglyphcache_serial_number.fetchAndAddRelaxed(1))
+    , m_serialNumber(next_qgltextureglyphcache_serial_number())
 {
 #ifdef QT_GL_TEXTURE_GLYPH_CACHE_DEBUG
     qDebug(" -> QGLTextureGlyphCache() %p for context %p.", this, QOpenGLContext::currentContext());

src/plugins/platforms/eglfs/deviceintegration/eglfs_emu/qeglfsemulatorintegration.cpp

@@ -122,13 +122,13 @@ EGLNativeWindowType QEglFSEmulatorIntegration::createNativeWindow(QPlatformWindo
 {
     Q_UNUSED(size);
     Q_UNUSED(format);
-    static QAtomicInt uniqueWindowId(1);
     QEglFSEmulatorScreen *screen = static_cast<QEglFSEmulatorScreen *>(platformWindow->screen());
     if (screen && setDisplay) {
         // Let the emulator know which screen the window surface is attached to
         setDisplay(screen->id());
     }
-    return EGLNativeWindowType(qintptr(uniqueWindowId.fetchAndAddRelaxed(1)));
+    static QBasicAtomicInt uniqueWindowId;
+    return EGLNativeWindowType(qintptr(1 + uniqueWindowId.fetchAndAddRelaxed(1)));
 }
 
 QT_END_NAMESPACE