QtBase (remainder): use printf-style qWarning/qDebug where possible (I)

The printf-style version of QDebug expands to a lot less code than the
std::ostream-style version. Of course, you pay in type safety (but
compilers warn about it these days), you cannot stream complex Qt
types and streaming QStrings is awkward, but in many cases you
actually improve on readability.

But the main reason is that something that's not supposed to be
executed under normal operation has no business bloating executable
code size.

This is not an attempt at converting all qWarnings() to printf-style,
only the low-hanging fruit.

In this first part, replace
   qWarning() << ""
with
   qWarning("...").

Had to fix broken qImDebug() definition. Instead of defining it as
a nullary macro in the QT_NO_DEBUG case and as a variadic macro in
the other, define it in both cases, as is customary, as a non-function
macro so that overload selection works without requiring variadic
macro support of the compiler.

Saves e.g. ~250b in text size in QtPrintSupport on optimized GCC 5.3
AMD64 builds.

Change-Id: Ie30fe2f7942115d5dbf99fff1750ae0d477c379f
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

7 files changed, 12 insertions, 12 deletions

diff --git a/src/plugins/platforms/xcb/qxcbbackingstore.cpp b/src/plugins/platforms/xcb/qxcbbackingstore.cpp
index 2e04799998..896eb61970 100644
--- a/src/plugins/platforms/xcb/qxcbbackingstore.cpp
+++ b/src/plugins/platforms/xcb/qxcbbackingstore.cpp
@@ -187,7 +187,7 @@ QXcbShmImage::QXcbShmImage(QXcbScreen *screen, const QSize &size, uint depth, QI
         m_xcb_image->data = (uint8_t *)malloc(segmentSize);
     } else {
         if (shmctl(m_shm_info.shmid, IPC_RMID, 0) == -1)
-            qWarning() << "QXcbBackingStore: Error while marking the shared memory segment to be destroyed";
+            qWarning("QXcbBackingStore: Error while marking the shared memory segment to be destroyed");
     }
 
     m_hasAlpha = QImage::toPixelFormat(format).alphaUsage() == QPixelFormat::UsesAlpha;
diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp
index 998f4884aa..73af6ead13 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection.cpp
@@ -2173,7 +2173,7 @@ void QXcbConnection::initializeXKB()
 #ifndef QT_NO_XKB
     const xcb_query_extension_reply_t *reply = xcb_get_extension_data(m_connection, &xcb_xkb_id);
     if (!reply || !reply->present) {
-        qWarning() << "Qt: XKEYBOARD extension not present on the X server.";
+        qWarning("Qt: XKEYBOARD extension not present on the X server.");
         xkb_first_event = 0;
         return;
     }
@@ -2227,7 +2227,7 @@ void QXcbConnection::initializeXKB()
     xcb_generic_error_t *error = xcb_request_check(c, select);
     if (error) {
         free(error);
-        qWarning() << "Qt: failed to select notify events from xcb-xkb";
+        qWarning("Qt: failed to select notify events from xcb-xkb");
         return;
     }
 #endif
diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index a141882fc4..b5e03e68fe 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/src/plugins/platforms/xcb/qxcbintegration.cpp
@@ -164,7 +164,7 @@ QXcbIntegration::QXcbIntegration(const QStringList &parameters, int &argc, char
 
     bool underDebugger = runningUnderDebugger();
     if (noGrabArg && doGrabArg && underDebugger) {
-        qWarning() << "Both -nograb and -dograb command line arguments specified. Please pick one. -nograb takes prcedence";
+        qWarning("Both -nograb and -dograb command line arguments specified. Please pick one. -nograb takes prcedence");
         doGrabArg = false;
     }
 
diff --git a/src/plugins/platforms/xcb/qxcbkeyboard.cpp b/src/plugins/platforms/xcb/qxcbkeyboard.cpp
index 4de7716703..a16e24061c 100644
--- a/src/plugins/platforms/xcb/qxcbkeyboard.cpp
+++ b/src/plugins/platforms/xcb/qxcbkeyboard.cpp
@@ -676,13 +676,13 @@ void QXcbKeyboard::printKeymapError(const char *error) const
 {
     qWarning() << error;
     if (xkb_context) {
-        qWarning() << "Current XKB configuration data search paths are: ";
+        qWarning("Current XKB configuration data search paths are: ");
         for (unsigned int i = 0; i < xkb_context_num_include_paths(xkb_context); ++i)
             qWarning() << xkb_context_include_path_get(xkb_context, i);
     }
-    qWarning() << "Use QT_XKB_CONFIG_ROOT environmental variable to provide an additional search path, "
-                  "add ':' as separator to provide several search paths and/or make sure that XKB configuration data "
-                  "directory contains recent enough contents, to update please see http://cgit.freedesktop.org/xkeyboard-config/ .";
+    qWarning("Use QT_XKB_CONFIG_ROOT environmental variable to provide an additional search path, "
+             "add ':' as separator to provide several search paths and/or make sure that XKB configuration data "
+             "directory contains recent enough contents, to update please see http://cgit.freedesktop.org/xkeyboard-config/ .");
 }
 
 void QXcbKeyboard::updateKeymap()
diff --git a/src/plugins/platforms/xcb/qxcbnativeinterface.cpp b/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
index eb7c5d2b02..f3066424ae 100644
--- a/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
+++ b/src/plugins/platforms/xcb/qxcbnativeinterface.cpp
@@ -203,7 +203,7 @@ void *QXcbNativeInterface::nativeResourceForContext(const QByteArray &resourceSt
 void *QXcbNativeInterface::nativeResourceForScreen(const QByteArray &resourceString, QScreen *screen)
 {
     if (!screen) {
-        qWarning() << "nativeResourceForScreen: null screen";
+        qWarning("nativeResourceForScreen: null screen");
         return Q_NULLPTR;
     }
 
diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 6ac28684a8..f3276e8976 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -372,7 +372,7 @@ void QXcbWindow::create()
             if (visual)
                 m_visualId = connection()->defaultVisualId();
             if (!visual)
-                qWarning() << "Could not use default visual id. Falling back to root_visual for screen.";
+                qWarning("Could not use default visual id. Falling back to root_visual for screen.");
         }
         if (!visual)
             visual = platformScreen->visualForId(m_visualId);
diff --git a/src/plugins/platforms/xcb/qxcbwmsupport.cpp b/src/plugins/platforms/xcb/qxcbwmsupport.cpp
index 38116ac239..470f021314 100644
--- a/src/plugins/platforms/xcb/qxcbwmsupport.cpp
+++ b/src/plugins/platforms/xcb/qxcbwmsupport.cpp
@@ -122,10 +122,10 @@ void QXcbWMSupport::updateVirtualRoots()
     } while (remaining > 0);
 
 #ifdef Q_XCB_DEBUG
-    qDebug() << "======== updateVirtualRoots";
+    qDebug("======== updateVirtualRoots");
     for (int i = 0; i < net_virtual_roots.size(); ++i)
         qDebug() << connection()->atomName(net_virtual_roots.at(i));
-    qDebug() << "======== updateVirtualRoots";
+    qDebug("======== updateVirtualRoots");
 #endif
 }