Backported r185231 from trunk to google/gcc-4_7. (issue 6151043)
Xinliang David Li
davidxl@google.com
Tue May 1 22:50:00 GMT 2012
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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