Mark qt_assert and qFatal as non-returning functions (excpt. MSVC)

This allows the compiler to optimise the code a bit better: since they
don't return, it can assume in the code after the Q_ASSERT that the
condition was true.

MSVC is the exception: with MSVC, we have the CrtDbgReport dialog,
which allows the developer to continue execution, inside the
debugger. Therefore, we can't mark any of those functions as
non-returning because they can, after all, return.

Unfortunately, the Q_ASSERT usually expands to no code in release
mode, so the improvement in code generation happens in debug mode
only...

Change-Id: I4d542d6853cd51c71ffab1d563ed64ef7c419115
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/corelib/global/qlogging.cpp b/src/corelib/global/qlogging.cpp
index f30df92a54..81fe82a973 100644
--- a/src/corelib/global/qlogging.cpp
+++ b/src/corelib/global/qlogging.cpp
@@ -201,6 +201,9 @@ void QMessageLogger::fatal(const char *msg, ...)
     va_list ap;
     va_start(ap, msg); // use variable arg list
     qt_message(QtFatalMsg, context, msg, ap);
+#ifndef Q_CC_MSVC
+    Q_UNREACHABLE();
+#endif
     va_end(ap);
 }