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* [gcc/devel/omp/gcc-10] libgomp: Don't access gomp_sem_t as int using atomics unconditionally
@ 2021-01-22 19:51 Kwok Yeung
0 siblings, 0 replies; only message in thread
From: Kwok Yeung @ 2021-01-22 19:51 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:2b93ffc7219aa53815ece2adb21f56dd265ec6bc
commit 2b93ffc7219aa53815ece2adb21f56dd265ec6bc
Author: Jakub Jelinek <jakub@redhat.com>
Date: Mon Jan 18 07:18:46 2021 +0100
libgomp: Don't access gomp_sem_t as int using atomics unconditionally
This patch introduces gomp_sem_getcount wrapper, which uses sem_getvalue
for POSIX and atomic loads for linux futex and accel. rtems for now
remains broken.
2021-01-18 Jakub Jelinek <jakub@redhat.com>
* config/linux/sem.h (gomp_sem_getcount): New function.
* config/posix/sem.h (gomp_sem_getcount): New function.
* config/posix/sem.c (gomp_sem_getcount): New function.
* config/accel/sem.h (gomp_sem_getcount): New function.
* task.c (task_fulfilled_p): Use gomp_sem_getcount.
(omp_fulfill_event): Likewise.
(cherry picked from commit d3b41bde961713ff4af7e18011126434c497edba)
Diff:
---
libgomp/ChangeLog.omp | 12 ++++++++++++
libgomp/config/accel/sem.h | 9 +++++++++
libgomp/config/linux/sem.h | 9 +++++++++
libgomp/config/posix/sem.c | 20 ++++++++++++++++++++
libgomp/config/posix/sem.h | 10 ++++++++++
libgomp/task.c | 4 ++--
6 files changed, 62 insertions(+), 2 deletions(-)
diff --git a/libgomp/ChangeLog.omp b/libgomp/ChangeLog.omp
index 684e09a378b..632b86989c3 100644
--- a/libgomp/ChangeLog.omp
+++ b/libgomp/ChangeLog.omp
@@ -1,3 +1,15 @@
+2021-01-22 Kwok Cheung Yeung <kcy@codesourcery.com>
+
+ Backport from mainline
+ 2021-01-18 Jakub Jelinek <jakub@redhat.com>
+
+ * config/linux/sem.h (gomp_sem_getcount): New function.
+ * config/posix/sem.h (gomp_sem_getcount): New function.
+ * config/posix/sem.c (gomp_sem_getcount): New function.
+ * config/accel/sem.h (gomp_sem_getcount): New function.
+ * task.c (task_fulfilled_p): Use gomp_sem_getcount.
+ (omp_fulfill_event): Likewise.
+
2021-01-22 Kwok Cheung Yeung <kcy@codesourcery.com>
Backport from mainline
diff --git a/libgomp/config/accel/sem.h b/libgomp/config/accel/sem.h
index af1b20b8483..3703842df54 100644
--- a/libgomp/config/accel/sem.h
+++ b/libgomp/config/accel/sem.h
@@ -62,4 +62,13 @@ gomp_sem_post (gomp_sem_t *sem)
{
(void) __atomic_add_fetch (sem, 1, MEMMODEL_RELEASE);
}
+
+static inline int
+gomp_sem_getcount (gomp_sem_t *sem)
+{
+ int count = __atomic_load_n (sem, MEMMODEL_RELAXED);
+ if (count < 0)
+ return -1;
+ return count;
+}
#endif /* GOMP_SEM_H */
diff --git a/libgomp/config/linux/sem.h b/libgomp/config/linux/sem.h
index 2e26a917a92..91e08f0fac8 100644
--- a/libgomp/config/linux/sem.h
+++ b/libgomp/config/linux/sem.h
@@ -85,4 +85,13 @@ gomp_sem_post (gomp_sem_t *sem)
if (__builtin_expect (count & SEM_WAIT, 0))
gomp_sem_post_slow (sem);
}
+
+static inline int
+gomp_sem_getcount (gomp_sem_t *sem)
+{
+ int count = __atomic_load_n (sem, MEMMODEL_RELAXED);
+ if ((count & SEM_WAIT) != 0)
+ return -1;
+ return count / SEM_INC;
+}
#endif /* GOMP_SEM_H */
diff --git a/libgomp/config/posix/sem.c b/libgomp/config/posix/sem.c
index e43bcf6c9e7..a2529de8332 100644
--- a/libgomp/config/posix/sem.c
+++ b/libgomp/config/posix/sem.c
@@ -112,6 +112,26 @@ void gomp_sem_destroy (gomp_sem_t *sem)
return;
}
+
+int gomp_sem_getcount (gomp_sem_t *sem)
+{
+ int ret, count;
+
+ ret = pthread_mutex_lock (&sem->mutex);
+ if (ret)
+ return -1;
+
+ count = sem->value;
+
+ ret = pthread_mutex_unlock (&sem->mutex);
+ if (ret)
+ return -1;
+
+ if (count < 0)
+ return -1;
+
+ return count;
+}
#else /* HAVE_BROKEN_POSIX_SEMAPHORES */
void
gomp_sem_wait (gomp_sem_t *sem)
diff --git a/libgomp/config/posix/sem.h b/libgomp/config/posix/sem.h
index 64d4f1ec1d6..bd58d4f057b 100644
--- a/libgomp/config/posix/sem.h
+++ b/libgomp/config/posix/sem.h
@@ -64,6 +64,8 @@ extern void gomp_sem_post (gomp_sem_t *sem);
extern void gomp_sem_destroy (gomp_sem_t *sem);
+extern int gomp_sem_getcount (gomp_sem_t *sem);
+
#else /* HAVE_BROKEN_POSIX_SEMAPHORES */
typedef sem_t gomp_sem_t;
@@ -84,5 +86,13 @@ static inline void gomp_sem_destroy (gomp_sem_t *sem)
{
sem_destroy (sem);
}
+
+static inline int gomp_sem_getcount (gomp_sem_t *sem)
+{
+ int val;
+ if (sem_getvalue (sem, &val) < 0)
+ return -1;
+ return val;
+}
#endif /* doesn't HAVE_BROKEN_POSIX_SEMAPHORES */
#endif /* GOMP_SEM_H */
diff --git a/libgomp/task.c b/libgomp/task.c
index 67bff47fa0b..9689a3edef0 100644
--- a/libgomp/task.c
+++ b/libgomp/task.c
@@ -330,7 +330,7 @@ gomp_task_handle_depend (struct gomp_task *task, struct gomp_task *parent,
static bool
task_fulfilled_p (struct gomp_task *task)
{
- return __atomic_load_n (&task->completion_sem, __ATOMIC_RELAXED);
+ return gomp_sem_getcount (&task->completion_sem) > 0;
}
/* Called when encountering an explicit task directive. If IF_CLAUSE is
@@ -2406,7 +2406,7 @@ omp_fulfill_event (omp_event_handle_t event)
struct gomp_thread *thr = gomp_thread ();
struct gomp_team *team = thr ? thr->ts.team : NULL;
- if (__atomic_load_n (sem, __ATOMIC_RELAXED))
+ if (gomp_sem_getcount (sem) > 0)
gomp_fatal ("omp_fulfill_event: %p event already fulfilled!\n", sem);
gomp_debug (0, "omp_fulfill_event: %p\n", sem);
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