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 <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.
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 <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.
+
2012-04-20 Thomas Schwinge <tho...@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 <asha...@google.com>
+ 2012-03-12 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.
+
2012-04-17 Teresa Johnson <tejohn...@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.
