Remove workaround for compilers not supporting thread_local

With C++11, all compilers support thread_local, which replaces the non-
standardized __thread attribute as a storage class.

The storage class was specifically introduced so that applications do
not have to deal with pthread APIs for TLS key management. We still
need to have some of that logic for adopting foreign threads, but we
can rely on thread_local so that we get a fast implementation of
QThread::currentThread() on all platforms.

Change-Id: Iba2b35d014044c4ab317a0e127c5d1f1fa4ecd4a
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 1 insertions, 22 deletions

diff --git a/src/corelib/thread/qthread_unix.cpp b/src/corelib/thread/qthread_unix.cpp
index 38e9c1c3ec..cb3c0d6bb1 100644
--- a/src/corelib/thread/qthread_unix.cpp
+++ b/src/corelib/thread/qthread_unix.cpp
@@ -108,20 +108,8 @@ Q_STATIC_ASSERT(sizeof(pthread_t) <= sizeof(Qt::HANDLE));
 
 enum { ThreadPriorityResetFlag = 0x80000000 };
 
-#if defined(Q_OS_LINUX) && defined(__GLIBC__) && (defined(Q_CC_GNU) || defined(Q_CC_INTEL)) && !defined(QT_LINUXBASE)
-/* LSB doesn't have __thread, https://lsbbugs.linuxfoundation.org/show_bug.cgi?id=993 */
-#define HAVE_TLS
-#endif
-#if defined(Q_CC_XLC) || defined (Q_CC_SUN)
-#define HAVE_TLS
-#endif
-#if defined(Q_OS_RTEMS)
-#define HAVE_TLS
-#endif
 
-#ifdef HAVE_TLS
-static __thread QThreadData *currentThreadData = 0;
-#endif
+static thread_local QThreadData *currentThreadData = 0;
 
 static pthread_once_t current_thread_data_once = PTHREAD_ONCE_INIT;
 static pthread_key_t current_thread_data_key;
@@ -182,28 +170,19 @@ Q_DESTRUCTOR_FUNCTION(destroy_current_thread_data_key)
 // Utility functions for getting, setting and clearing thread specific data.
 static QThreadData *get_thread_data()
 {
-#ifdef HAVE_TLS
     return currentThreadData;
-#else
-    pthread_once(&current_thread_data_once, create_current_thread_data_key);
-    return reinterpret_cast<QThreadData *>(pthread_getspecific(current_thread_data_key));
-#endif
 }
 
 static void set_thread_data(QThreadData *data)
 {
-#ifdef HAVE_TLS
     currentThreadData = data;
-#endif
     pthread_once(&current_thread_data_once, create_current_thread_data_key);
     pthread_setspecific(current_thread_data_key, data);
 }
 
 static void clear_thread_data()
 {
-#ifdef HAVE_TLS
     currentThreadData = 0;
-#endif
     pthread_setspecific(current_thread_data_key, 0);
 }