On Wed, Jan 18, 2012 at 3:21 PM, Richard Guenther <rguent...@suse.de> wrote:
>
> This fixes PR49484 by protecting __gcov_flush against concurrent
> execution. To be able to use the gthread facility I have to
> introduce the requirement that __GTHREAD_MUTEX_INIT_FUNCTION
> is always available, even if __GTHREAD_MUTEX_INIT is available as
> otherwise no dynamic initialization of a mutex is possible.
> I have adjusted gthr-posix.h and gthr-single.h only - target
> maintainers, please update your ports accordingly in advance.
>
> Boostrap and regtest on x86_64-unknown-linux-gnu is ongoing,
> but this looks like something for stage1 anyway.
Bootstrap and regtest finished ok. I am going to commit this without "fixing"
eventually broken targets that I know nothing of. See above.
Unless I hear objections until tomorrow.
Thanks,
Richard.
> Richard.
>
> 2012-01-18 Richard Guenther <rguent...@suse.de>
>
> * gthr.h (__GTHREAD_MUTEX_INIT_FUNCTION): Adjust specification.
> * gthr-posix.h (__GTHREAD_MUTEX_INIT_FUNCTION): Define.
> (__gthread_mutex_init_function): New function.
> * gthr-single.h (__GTHREAD_MUTEX_INIT_FUNCTION): Define.
>
> PR gcov/49484
> * libgcov.c: Include gthr.h.
> (__gcov_flush_mx): New global variable.
> (init_mx, init_mx_once): New functions.
> (__gcov_flush): Protect self with a mutex.
> (__gcov_fork): Re-initialize mutex after forking.
> * unwind-dw2-fde.c: Change condition under which to use
> __GTHREAD_MUTEX_INIT_FUNCTION.
>
> Index: libgcc/libgcov.c
> ===================================================================
> *** libgcc/libgcov.c (revision 183270)
> --- libgcc/libgcov.c (working copy)
> *************** see the files COPYING3 and COPYING.RUNTI
> *** 30,35 ****
> --- 30,36 ----
> #include "coretypes.h"
> #include "tm.h"
> #include "libgcc_tm.h"
> + #include "gthr.h"
>
> #if defined(inhibit_libc)
> #define IN_LIBGCOV (-1)
> *************** __gcov_init (struct gcov_info *info)
> *** 705,710 ****
> --- 706,730 ----
> info->version = 0;
> }
>
> + #ifdef __GTHREAD_MUTEX_INIT
> + ATTRIBUTE_HIDDEN __gthread_mutex_t __gcov_flush_mx = __GTHREAD_MUTEX_INIT;
> + #define init_mx_once()
> + #else
> + __gthread_mutex_t __gcov_flush_mx ATTRIBUTE_HIDDEN;
> +
> + static void
> + init_mx (void)
> + {
> + __GTHREAD_MUTEX_INIT_FUNCTION (&mx);
> + }
> + static void
> + init_mx_once (void)
> + {
> + static __gthread_once_t once = __GTHREAD_ONCE_INIT;
> + __gthread_once (&once, init_mx);
> + }
> + #endif
> +
> /* Called before fork or exec - write out profile information gathered so
> far and reset it to zero. This avoids duplication or loss of the
> profile information gathered so far. */
> *************** __gcov_flush (void)
> *** 714,719 ****
> --- 734,742 ----
> {
> const struct gcov_info *gi_ptr;
>
> + init_mx_once ();
> + __gthread_mutex_lock (&__gcov_flush_mx);
> +
> gcov_exit ();
> for (gi_ptr = gcov_list; gi_ptr; gi_ptr = gi_ptr->next)
> {
> *************** __gcov_flush (void)
> *** 737,742 ****
> --- 760,767 ----
> }
> }
> }
> +
> + __gthread_mutex_unlock (&__gcov_flush_mx);
> }
>
> #endif /* L_gcov */
> *************** __gcov_ior_profiler (gcov_type *counters
> *** 975,982 ****
> pid_t
> __gcov_fork (void)
> {
> __gcov_flush ();
> ! return fork ();
> }
> #endif
>
> --- 1000,1012 ----
> pid_t
> __gcov_fork (void)
> {
> + pid_t pid;
> + extern __gthread_mutex_t __gcov_flush_mx;
> __gcov_flush ();
> ! pid = fork ();
> ! if (pid == 0)
> ! __GTHREAD_MUTEX_INIT_FUNCTION (&__gcov_flush_mx);
> ! return pid;
> }
> #endif
>
> Index: libgcc/unwind-dw2-fde.c
> ===================================================================
> *** libgcc/unwind-dw2-fde.c (revision 183270)
> --- libgcc/unwind-dw2-fde.c (working copy)
> *************** static struct object *seen_objects;
> *** 47,57 ****
>
> #ifdef __GTHREAD_MUTEX_INIT
> static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
> #else
> static __gthread_mutex_t object_mutex;
> - #endif
>
> - #ifdef __GTHREAD_MUTEX_INIT_FUNCTION
> static void
> init_object_mutex (void)
> {
> --- 47,56 ----
>
> #ifdef __GTHREAD_MUTEX_INIT
> static __gthread_mutex_t object_mutex = __GTHREAD_MUTEX_INIT;
> + #define init_object_mutex_once()
> #else
> static __gthread_mutex_t object_mutex;
>
> static void
> init_object_mutex (void)
> {
> *************** init_object_mutex_once (void)
> *** 64,71 ****
> static __gthread_once_t once = __GTHREAD_ONCE_INIT;
> __gthread_once (&once, init_object_mutex);
> }
> - #else
> - #define init_object_mutex_once()
> #endif
>
> /* Called from crtbegin.o to register the unwind info for an object. */
> --- 63,68 ----
> Index: libgcc/gthr-posix.h
> ===================================================================
> *** libgcc/gthr-posix.h (revision 183270)
> --- libgcc/gthr-posix.h (working copy)
> *************** typedef struct timespec __gthread_time_t
> *** 63,68 ****
> --- 63,69 ----
> #define __GTHREAD_HAS_COND 1
>
> #define __GTHREAD_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
> + #define __GTHREAD_MUTEX_INIT_FUNCTION __gthread_mutex_init_function
> #define __GTHREAD_ONCE_INIT PTHREAD_ONCE_INIT
> #if defined(PTHREAD_RECURSIVE_MUTEX_INITIALIZER)
> #define __GTHREAD_RECURSIVE_MUTEX_INIT PTHREAD_RECURSIVE_MUTEX_INITIALIZER
> *************** __gthread_setspecific (__gthread_key_t _
> *** 731,736 ****
> --- 732,745 ----
> }
>
> static inline int
> + __gthread_mutex_init_function (__gthread_mutex_t *__mutex)
> + {
> + if (__gthread_active_p ())
> + return __gthrw_(pthread_mutex_init) (__mutex, NULL);
> + return 0;
> + }
> +
> + static inline int
> __gthread_mutex_destroy (__gthread_mutex_t *__mutex)
> {
> if (__gthread_active_p ())
> Index: libgcc/gthr-single.h
> ===================================================================
> *** libgcc/gthr-single.h (revision 183270)
> --- libgcc/gthr-single.h (working copy)
> *************** typedef int __gthread_recursive_mutex_t;
> *** 36,41 ****
> --- 36,42 ----
>
> #define __GTHREAD_ONCE_INIT 0
> #define __GTHREAD_MUTEX_INIT 0
> + #define __GTHREAD_MUTEX_INIT_FUNCTION (mx)
> #define __GTHREAD_RECURSIVE_MUTEX_INIT 0
>
> #define UNUSED __attribute__((unused))
> Index: libgcc/gthr.h
> ===================================================================
> --- libgcc/gthr.h (revision 183270)
> +++ libgcc/gthr.h (working copy)
> @@ -52,11 +52,12 @@ see the files COPYING3 and COPYING.RUNTI
> to initialize __gthread_mutex_t to get a fast
> non-recursive mutex.
> __GTHREAD_MUTEX_INIT_FUNCTION
> - some systems can't initialize a mutex without a
> - function call. On such systems, define this to a
> - function which looks like this:
> + to initialize __gthread_mutex_t to get a fast
> + non-recursive mutex.
> + Define this to a function which looks like this:
> void __GTHREAD_MUTEX_INIT_FUNCTION (__gthread_mutex_t *)
> - Don't define __GTHREAD_MUTEX_INIT in this case
> + Some systems can't initialize a mutex without a
> + function call. Don't define __GTHREAD_MUTEX_INIT in this
> case.
> __GTHREAD_RECURSIVE_MUTEX_INIT
> __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION
> as above, but for a recursive mutex.
