Use Q_UNLIKELY for every qFatal()/qCritical()

If, after checking a condition, we issue a qFatal()
or a qCritical(), by definition that check is
unlikely to be true.

Tell the compiler so it can move the error handling
code out of the normal code path to increase the
effective icache size.

Moved conditional code around where possible so that
we could always use Q_UNLIKELY, instead of having to
revert to Q_LIKELY here and there.

In some cases, simplified the expressions newly wrapped
in Q_UNLIKELY as a drive-by.

Change-Id: I67537d62b04bc6977d69254690c5ebbdf98bfd6d
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

6 files changed, 27 insertions, 29 deletions

diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsintegration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsintegration.cpp
index d1814fb85d..789f2fa86f 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsintegration.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsintegration.cpp
@@ -77,7 +77,7 @@ void QEglFSKmsIntegration::platformInit()
         qCDebug(qLcEglfsKmsDebug) << "Found the following video devices:" << devices;
         d->deleteLater();
 
-        if (devices.isEmpty())
+        if (Q_UNLIKELY(devices.isEmpty()))
             qFatal("Could not find DRM device!");
 
         m_devicePath = devices.first();
@@ -85,7 +85,7 @@ void QEglFSKmsIntegration::platformInit()
     }
 
     m_device = new QEglFSKmsDevice(this, m_devicePath);
-    if (!m_device->open())
+    if (Q_UNLIKELY(!m_device->open()))
         qFatal("Could not open device %s - aborting!", qPrintable(m_devicePath));
 }
 
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
index 1ddcb3b862..b364056b91 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldeviceintegration.cpp
@@ -52,20 +52,20 @@ QEglFSKmsEglDeviceIntegration::QEglFSKmsEglDeviceIntegration()
 
 void QEglFSKmsEglDeviceIntegration::platformInit()
 {
-    if (!query_egl_device())
+    if (Q_UNLIKELY(!query_egl_device()))
         qFatal("Could not set up EGL device!");
 
     const char *deviceName = m_funcs->query_device_string(m_egl_device, EGL_DRM_DEVICE_FILE_EXT);
-    if (!deviceName)
+    if (Q_UNLIKELY(!deviceName))
         qFatal("Failed to query device name from EGLDevice");
 
     qCDebug(qLcEglfsKmsDebug, "Opening %s", deviceName);
 
     m_dri_fd = drmOpen(deviceName, Q_NULLPTR);
-    if (m_dri_fd < 0)
+    if (Q_UNLIKELY(m_dri_fd < 0))
         qFatal("Could not open DRM device");
 
-    if (!setup_kms())
+    if (Q_UNLIKELY(!setup_kms()))
         qFatal("Could not set up KMS on device %s!", m_device.constData());
 
     qCDebug(qLcEglfsKmsDebug, "DRM/KMS initialized");
@@ -100,14 +100,14 @@ EGLDisplay QEglFSKmsEglDeviceIntegration::createDisplay(EGLNativeDisplayType nat
         display = eglGetDisplay(nativeDisplay);
     }
 
-    if (display == EGL_NO_DISPLAY)
+    if (Q_UNLIKELY(display == EGL_NO_DISPLAY))
         qFatal("Could not get EGL display");
 
     EGLint major, minor;
-    if (!eglInitialize(display, &major, &minor))
+    if (Q_UNLIKELY(!eglInitialize(display, &major, &minor)))
         qFatal("Could not initialize egl display");
 
-    if (!eglBindAPI(EGL_OPENGL_ES_API))
+    if (Q_UNLIKELY(!eglBindAPI(EGL_OPENGL_ES_API)))
         qFatal("Failed to bind EGL_OPENGL_ES_API\n");
 
     return display;
@@ -255,8 +255,8 @@ QEglFSWindow *QEglFSKmsEglDeviceIntegration::createWindow(QWindow *window) const
     QEglJetsonTK1Window *eglWindow = new QEglJetsonTK1Window(window, this);
 
     m_funcs->initialize(eglWindow->screen()->display());
-    if (!(m_funcs->has_egl_output_base && m_funcs->has_egl_output_drm && m_funcs->has_egl_stream
-          && m_funcs->has_egl_stream_producer_eglsurface && m_funcs->has_egl_stream_consumer_egloutput))
+    if (Q_UNLIKELY(!(m_funcs->has_egl_output_base && m_funcs->has_egl_output_drm && m_funcs->has_egl_stream &&
+                     m_funcs->has_egl_stream_producer_eglsurface && m_funcs->has_egl_stream_consumer_egloutput)))
         qFatal("Required extensions missing!");
 
     return eglWindow;
@@ -298,7 +298,7 @@ void QEglFSKmsEglDeviceIntegration::waitForVSync(QPlatformSurface *) const
                                  -1, 0, 0,
                                  &m_drm_connector->connector_id, 1,
                                  const_cast<const drmModeModeInfoPtr>(&m_drm_mode));
-        if (ret)
+        if (Q_UNLIKELY(ret))
             qFatal("drmModeSetCrtc failed");
     }
 }
@@ -367,7 +367,7 @@ bool QEglFSKmsEglDeviceIntegration::setup_kms()
         }
     }
 
-    if (crtc == 0)
+    if (Q_UNLIKELY(crtc == 0))
         qFatal("No suitable CRTC available");
 
     m_drm_connector = connector;
@@ -387,7 +387,7 @@ bool QEglFSKmsEglDeviceIntegration::setup_kms()
 bool QEglFSKmsEglDeviceIntegration::query_egl_device()
 {
     m_funcs = new QEGLStreamConvenience;
-    if (!m_funcs->has_egl_device_base)
+    if (Q_UNLIKELY(!m_funcs->has_egl_device_base))
         qFatal("EGL_EXT_device_base missing");
 
     EGLint num_devices = 0;
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp
index 4d29b96608..ef586622e2 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp
@@ -172,7 +172,7 @@ void QEglFSX11Integration::sendConnectionEvent(xcb_atom_t a)
 void QEglFSX11Integration::platformInit()
 {
     m_display = XOpenDisplay(0);
-    if (!m_display)
+    if (Q_UNLIKELY(!m_display))
         qFatal("Could not open display");
 
     XSetEventQueueOwner(DISPLAY, XCBOwnsEventQueue);
diff --git a/src/plugins/platforms/eglfs/qeglfsdeviceintegration.cpp b/src/plugins/platforms/eglfs/qeglfsdeviceintegration.cpp
index 064b9f6306..e55a17585e 100644
--- a/src/plugins/platforms/eglfs/qeglfsdeviceintegration.cpp
+++ b/src/plugins/platforms/eglfs/qeglfsdeviceintegration.cpp
@@ -155,7 +155,7 @@ void QEGLDeviceIntegration::platformInit()
 
     framebuffer = qt_safe_open(fbDev, O_RDONLY);
 
-    if (framebuffer == -1) {
+    if (Q_UNLIKELY(framebuffer == -1)) {
         qWarning("EGLFS: Failed to open %s", fbDev.constData());
         qFatal("EGLFS: Can't continue without a display");
     }
diff --git a/src/plugins/platforms/eglfs/qeglfsintegration.cpp b/src/plugins/platforms/eglfs/qeglfsintegration.cpp
index 2086ce56e2..001dd76803 100644
--- a/src/plugins/platforms/eglfs/qeglfsintegration.cpp
+++ b/src/plugins/platforms/eglfs/qeglfsintegration.cpp
@@ -118,11 +118,11 @@ void QEglFSIntegration::initialize()
     qt_egl_device_integration()->platformInit();
 
     m_display = qt_egl_device_integration()->createDisplay(nativeDisplay());
-    if (m_display == EGL_NO_DISPLAY)
+    if (Q_UNLIKELY(m_display == EGL_NO_DISPLAY))
         qFatal("Could not open egl display");
 
     EGLint major, minor;
-    if (!eglInitialize(m_display, &major, &minor))
+    if (Q_UNLIKELY(!eglInitialize(m_display, &major, &minor)))
         qFatal("Could not initialize egl display");
 
     m_inputContext = QPlatformInputContextFactory::create();
diff --git a/src/plugins/platforms/eglfs/qeglfswindow.cpp b/src/plugins/platforms/eglfs/qeglfswindow.cpp
index 8301be8c17..b29981bc98 100644
--- a/src/plugins/platforms/eglfs/qeglfswindow.cpp
+++ b/src/plugins/platforms/eglfs/qeglfswindow.cpp
@@ -102,17 +102,15 @@ void QEglFSWindow::create()
     QEglFSScreen *screen = this->screen();
     QOpenGLCompositor *compositor = QOpenGLCompositor::instance();
     if (screen->primarySurface() != EGL_NO_SURFACE) {
-        if (isRaster() && compositor->targetWindow()) {
-            m_format = compositor->targetWindow()->format();
-            return;
-        }
-
+        if (Q_UNLIKELY(!isRaster() || !compositor->targetWindow())) {
 #if !defined(Q_OS_ANDROID) || defined(Q_OS_ANDROID_NO_SDK)
-        // We can have either a single OpenGL window or multiple raster windows.
-        // Other combinations cannot work.
-        qFatal("EGLFS: OpenGL windows cannot be mixed with others.");
+            // We can have either a single OpenGL window or multiple raster windows.
+            // Other combinations cannot work.
+            qFatal("EGLFS: OpenGL windows cannot be mixed with others.");
 #endif
-
+            return;
+        }
+        m_format = compositor->targetWindow()->format();
         return;
     }
 
@@ -122,7 +120,7 @@ void QEglFSWindow::create()
 
     resetSurface();
 
-    if (m_surface == EGL_NO_SURFACE) {
+    if (Q_UNLIKELY(m_surface == EGL_NO_SURFACE)) {
         EGLint error = eglGetError();
         eglTerminate(screen->display());
         qFatal("EGL Error : Could not create the egl surface: error = 0x%x\n", error);
@@ -135,7 +133,7 @@ void QEglFSWindow::create()
         context->setShareContext(qt_gl_global_share_context());
         context->setFormat(m_format);
         context->setScreen(window()->screen());
-        if (!context->create())
+        if (Q_UNLIKELY(!context->create()))
             qFatal("EGLFS: Failed to create compositing context");
         compositor->setTarget(context, window());
     }