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Re: Backported r185231 from trunk to google/gcc-4_7. (issue 6151043)


ok.

David

On Tue, May 1, 2012 at 3:47 PM,  <asharif@chromium.org> wrote:
> Reviewers: xur, davidxl,
>
> Message:
> Please take a look at this.
>
> Description:
> This fixes an issue with profile collection when multiple threads call
> fork() around the same time.
>
> 2012-03-12 ?Richard Guenther ?<rguenther@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.
>
>
> Please review this at http://codereview.appspot.com/6151043/
>
> Affected files:
> ? M ? ?.
> ?M ? ? libgcc/ChangeLog
> ?M ? ? libgcc/ChangeLog.google-4_7
> ?M ? ? libgcc/gthr-posix.h
> ?M ? ? libgcc/gthr-single.h
> ?M ? ? libgcc/gthr.h
> ?M ? ? libgcc/libgcov.c
> ?M ? ? libgcc/unwind-dw2-fde.c
>
>
> Index: .
> ===================================================================
> --- . ? (revision 187027)
> +++ . ? (working copy)
>
> Property changes on: .
> ___________________________________________________________________
> Modified: svn:mergeinfo
> ? Merged /trunk:r185231
> Index: libgcc/ChangeLog
> ===================================================================
> --- libgcc/ChangeLog ? ?(revision 187027)
> +++ libgcc/ChangeLog ? ?(working copy)
> @@ -1,3 +1,19 @@
> +2012-03-12 ?Richard Guenther ?<rguenther@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.
> +
> ?2012-04-20 ?Thomas Schwinge ?<thomas@codesourcery.com>
>
> ? ? ? ?struct siginfo vs. siginfo_t
> Index: libgcc/ChangeLog.google-4_7
> ===================================================================
> --- libgcc/ChangeLog.google-4_7 (revision 187027)
> +++ libgcc/ChangeLog.google-4_7 (working copy)
> @@ -1,3 +1,20 @@
> +2012-05-01 ?Ahmad Sharif ?<asharif@google.com>
> + ? ? ? 2012-03-12 ?Richard Guenther ?<rguenther@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.
> +
> ?2012-04-17 ?Teresa Johnson ?<tejohnson@google.com>
>
> ? ? ? ?Backport from google/main rev r186550
> Index: libgcc/gthr-single.h
> ===================================================================
> --- libgcc/gthr-single.h ? ? ? ?(revision 187027)
> +++ libgcc/gthr-single.h ? ? ? ?(working copy)
> @@ -36,6 +36,7 @@
>
> ?#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/libgcov.c
> ===================================================================
> --- libgcc/libgcov.c ? ?(revision 187027)
> +++ libgcc/libgcov.c ? ?(working copy)
> @@ -48,6 +48,7 @@
> ?#include "tm.h"
> ?#endif /* __KERNEL__ */
> ?#include "libgcc_tm.h"
> +#include "gthr.h"
>
> ?#if 1
> ?#define THREAD_PREFIX __thread
> @@ -668,6 +669,25 @@
> ? 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. ?*/
> @@ -677,6 +697,9 @@
> ?{
> ? const struct gcov_info *gi_ptr;
>
> + ?init_mx_once ();
> + ?__gthread_mutex_lock (&__gcov_flush_mx);
> +
> ? __gcov_stop_pmu_profiler ();
> ? gcov_exit ();
> ? for (gi_ptr = __gcov_list; gi_ptr; gi_ptr = gi_ptr->next)
> @@ -700,6 +723,7 @@
> ? ? ? ? }
> ? ? }
> ? __gcov_start_pmu_profiler ();
> + ?__gthread_mutex_unlock (&__gcov_flush_mx);
> ?}
>
> ?#else /* __GCOV_KERNEL__ */
> @@ -1721,8 +1745,13 @@
> ?pid_t
> ?__gcov_fork (void)
> ?{
> + ?pid_t pid;
> + ?extern __gthread_mutex_t __gcov_flush_mx;
> ? __gcov_flush ();
> - ?return fork ();
> + ?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 187027)
> +++ libgcc/unwind-dw2-fde.c ? ? (working copy)
> @@ -47,11 +47,10 @@
>
> ?#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;
> -#endif
>
> -#ifdef __GTHREAD_MUTEX_INIT_FUNCTION
> ?static void
> ?init_object_mutex (void)
> ?{
> @@ -64,8 +63,6 @@
> ? 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. ?*/
> Index: libgcc/gthr-posix.h
> ===================================================================
> --- libgcc/gthr-posix.h (revision 187027)
> +++ libgcc/gthr-posix.h (working copy)
> @@ -63,6 +63,7 @@
> ?#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
> @@ -754,6 +755,14 @@
> ?#endif
>
> ?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.h
> ===================================================================
> --- libgcc/gthr.h ? ? ? (revision 187027)
> +++ libgcc/gthr.h ? ? ? (working copy)
> @@ -52,11 +52,12 @@
> ? ? ? ? ? ? ? ?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.
>
>


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