/* Threads compatibility routines for libgcc2 and libobjc. */
/* Compile this one with gcc. */
-/* Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+/* Copyright (C) 2004, 2005, 2007 Free Software Foundation, Inc.
This file is part of GCC.
#if SUPPORTS_WEAK && GTHREAD_USE_WEAK
+/* On Solaris 2.6 up to 9, the libc exposes a POSIX threads interface even if
+ -pthreads is not specified. The functions are dummies and most return an
+ error value. However pthread_once returns 0 without invoking the routine
+ it is passed so we cannot pretend that the interface is active if -pthreads
+ is not specified. On Solaris 2.5.1, the interface is not exposed at all so
+ we need to play the usual game with weak symbols. On Solaris 10 and up, a
+ working interface is always exposed. */
+
+#if defined(__sun) && defined(__svr4__)
+
+static volatile int __gthread_active = -1;
+
+static void
+__gthread_trigger (void)
+{
+ __gthread_active = 1;
+}
+
+static inline int
+__gthread_active_p (void)
+{
+ static pthread_mutex_t __gthread_active_mutex = PTHREAD_MUTEX_INITIALIZER;
+ static pthread_once_t __gthread_active_once = PTHREAD_ONCE_INIT;
+
+ /* Avoid reading __gthread_active twice on the main code path. */
+ int __gthread_active_latest_value = __gthread_active;
+
+ /* This test is not protected to avoid taking a lock on the main code
+ path so every update of __gthread_active in a threaded program must
+ be atomic with regard to the result of the test. */
+ if (__builtin_expect (__gthread_active_latest_value < 0, 0))
+ {
+ if (__gthrw_(pthread_once))
+ {
+ /* If this really is a threaded program, then we must ensure that
+ __gthread_active has been set to 1 before exiting this block. */
+ __gthrw_(pthread_mutex_lock) (&__gthread_active_mutex);
+ __gthrw_(pthread_once) (&__gthread_active_once, __gthread_trigger);
+ __gthrw_(pthread_mutex_unlock) (&__gthread_active_mutex);
+ }
+
+ /* Make sure we'll never enter this block again. */
+ if (__gthread_active < 0)
+ __gthread_active = 0;
+
+ __gthread_active_latest_value = __gthread_active;
+ }
+
+ return __gthread_active_latest_value != 0;
+}
+
+#else /* not Solaris */
+
static inline int
__gthread_active_p (void)
{
return __gthread_active_ptr != 0;
}
+#endif /* Solaris */
+
#else /* not SUPPORTS_WEAK */
+/* Similar to Solaris, HP-UX 11 for PA-RISC provides stubs for pthread
+ calls in shared flavors of the HP-UX C library. Most of the stubs
+ have no functionality. The details are described in the "libc cumulative
+ patch" for each subversion of HP-UX 11. There are two special interfaces
+ provided for checking whether an application is linked to a pthread
+ library or not. However, these interfaces aren't available in early
+ libc versions. We also can't use pthread_once as some libc versions
+ call the init function. So, we use pthread_create to check whether it
+ is possible to create a thread or not. The stub implementation returns
+ the error number ENOSYS. */
+
+#if defined(__hppa__) && defined(__hpux__)
+
+#include <errno.h>
+
+static volatile int __gthread_active = -1;
+
+static void *
+__gthread_start (void *arg __attribute__((unused)))
+{
+ return NULL;
+}
+
+static void __gthread_active_init (void) __attribute__((noinline));
+static void
+__gthread_active_init (void)
+{
+ static pthread_mutex_t __gthread_active_mutex = PTHREAD_MUTEX_INITIALIZER;
+ pthread_t t;
+ int result;
+
+ __gthrw_(pthread_mutex_lock) (&__gthread_active_mutex);
+ if (__gthread_active < 0)
+ {
+ result = __gthrw_(pthread_create) (&t, NULL, __gthread_start, NULL);
+ if (result != ENOSYS)
+ {
+ __gthread_active = 1;
+ if (!result)
+ __gthrw_(pthread_join) (t, NULL);
+ }
+ else
+ __gthread_active = 0;
+ }
+ __gthrw_(pthread_mutex_unlock) (&__gthread_active_mutex);
+}
+
+static inline int
+__gthread_active_p (void)
+{
+ /* Avoid reading __gthread_active twice on the main code path. */
+ int __gthread_active_latest_value = __gthread_active;
+
+ /* This test is not protected to avoid taking a lock on the main code
+ path so every update of __gthread_active in a threaded program must
+ be atomic with regard to the result of the test. */
+ if (__builtin_expect (__gthread_active_latest_value < 0, 0))
+ {
+ __gthread_active_init ();
+ __gthread_active_latest_value = __gthread_active;
+ }
+
+ return __gthread_active_latest_value != 0;
+}
+
+#else /* not hppa-hpux */
+
static inline int
__gthread_active_p (void)
{
return 1;
}
+#endif /* hppa-hpux */
+
#endif /* SUPPORTS_WEAK */
#ifdef _LIBOBJC
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