-/* Copyright (C) 2007, 2008 Free Software Foundation, Inc.
+/* Copyright (C) 2007, 2008, 2009, 2011 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU OpenMP Library (libgomp).
Libgomp is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
+ FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.
- You should have received a copy of the GNU Lesser General Public License
- along with libgomp; see the file COPYING.LIB. If not, write to the
- Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
- MA 02110-1301, USA. */
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
-/* As a special exception, if you link this library with other files, some
- of which are compiled with GCC, to produce an executable, this library
- does not by itself cause the resulting executable to be covered by the
- GNU General Public License. This exception does not however invalidate
- any other reasons why the executable file might be covered by the GNU
- General Public License. */
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
/* This file handles the maintainence of tasks in response to task
creation and termination. */
task->kind = GOMP_TASK_IMPLICIT;
task->in_taskwait = false;
task->in_tied_task = false;
+ task->final_task = false;
task->children = NULL;
gomp_sem_init (&task->taskwait_sem, 0);
}
void
GOMP_task (void (*fn) (void *), void *data, void (*cpyfn) (void *, void *),
- long arg_size, long arg_align, bool if_clause,
- unsigned flags __attribute__((unused)))
+ long arg_size, long arg_align, bool if_clause, unsigned flags)
{
struct gomp_thread *thr = gomp_thread ();
struct gomp_team *team = thr->ts.team;
#endif
if (!if_clause || team == NULL
+ || (thr->task && thr->task->final_task)
|| team->task_count > 64 * team->nthreads)
{
struct gomp_task task;
gomp_init_task (&task, thr->task, gomp_icv (false));
task.kind = GOMP_TASK_IFFALSE;
+ task.final_task = (thr->task && thr->task->final_task) || (flags & 2);
if (thr->task)
task.in_tied_task = thr->task->in_tied_task;
thr->task = &task;
}
else
fn (data);
- if (task.children)
+ /* Access to "children" is normally done inside a task_lock
+ mutex region, but the only way this particular task.children
+ can be set is if this thread's task work function (fn)
+ creates children. So since the setter is *this* thread, we
+ need no barriers here when testing for non-NULL. We can have
+ task.children set by the current thread then changed by a
+ child thread, but seeing a stale non-NULL value is not a
+ problem. Once past the task_lock acquisition, this thread
+ will see the real value of task.children. */
+ if (task.children != NULL)
{
gomp_mutex_lock (&team->task_lock);
gomp_clear_parent (task.children);
task->fn = fn;
task->fn_data = arg;
task->in_tied_task = true;
+ task->final_task = (flags & 2) >> 1;
gomp_mutex_lock (&team->task_lock);
if (parent->children)
{
parent->children = child_task->next_child;
else
{
- parent->children = NULL;
+ /* We access task->children in GOMP_taskwait
+ outside of the task lock mutex region, so
+ need a release barrier here to ensure memory
+ written by child_task->fn above is flushed
+ before the NULL is written. */
+ __atomic_store_n (&parent->children, NULL,
+ MEMMODEL_RELEASE);
if (parent->in_taskwait)
gomp_sem_post (&parent->taskwait_sem);
}
gomp_team_barrier_done (&team->barrier, state);
gomp_mutex_unlock (&team->task_lock);
gomp_team_barrier_wake (&team->barrier, 0);
+ gomp_mutex_lock (&team->task_lock);
}
}
}
struct gomp_task *child_task = NULL;
struct gomp_task *to_free = NULL;
- if (task == NULL || task->children == NULL)
+ /* The acquire barrier on load of task->children here synchronizes
+ with the write of a NULL in gomp_barrier_handle_tasks. It is
+ not necessary that we synchronize with other non-NULL writes at
+ this point, but we must ensure that all writes to memory by a
+ child thread task work function are seen before we exit from
+ GOMP_taskwait. */
+ if (task == NULL
+ || __atomic_load_n (&task->children, MEMMODEL_ACQUIRE) == NULL)
return;
+
gomp_mutex_lock (&team->task_lock);
while (1)
{
}
}
}
+
+/* Called when encountering a taskyield directive. */
+
+void
+GOMP_taskyield (void)
+{
+ /* Nothing at the moment. */
+}
+
+int
+omp_in_final (void)
+{
+ struct gomp_thread *thr = gomp_thread ();
+ return thr->task && thr->task->final_task;
+}
+
+ialias (omp_in_final)
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