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+/* Copyright (C) 2005, 2008, 2009 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 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 General Public License for
+ more details.
+
+ 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.
+
+ 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 is a Linux specific implementation of the public OpenMP locking
+ primitives. This implementation uses atomic instructions and the futex
+ syscall. */
+
+#include <string.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include "wait.h"
+
+
+/* The internal gomp_mutex_t and the external non-recursive omp_lock_t
+ have the same form. Re-use it. */
+
+void
+gomp_init_lock_30 (omp_lock_t *lock)
+{
+ gomp_mutex_init (lock);
+}
+
+void
+gomp_destroy_lock_30 (omp_lock_t *lock)
+{
+ gomp_mutex_destroy (lock);
+}
+
+void
+gomp_set_lock_30 (omp_lock_t *lock)
+{
+ gomp_mutex_lock (lock);
+}
+
+void
+gomp_unset_lock_30 (omp_lock_t *lock)
+{
+ gomp_mutex_unlock (lock);
+}
+
+int
+gomp_test_lock_30 (omp_lock_t *lock)
+{
+ return __sync_bool_compare_and_swap (lock, 0, 1);
+}
+
+void
+gomp_init_nest_lock_30 (omp_nest_lock_t *lock)
+{
+ memset (lock, '\0', sizeof (*lock));
+}
+
+void
+gomp_destroy_nest_lock_30 (omp_nest_lock_t *lock)
+{
+}
+
+void
+gomp_set_nest_lock_30 (omp_nest_lock_t *lock)
+{
+ void *me = gomp_icv (true);
+
+ if (lock->owner != me)
+ {
+ gomp_mutex_lock (&lock->lock);
+ lock->owner = me;
+ }
+
+ lock->count++;
+}
+
+void
+gomp_unset_nest_lock_30 (omp_nest_lock_t *lock)
+{
+ if (--lock->count == 0)
+ {
+ lock->owner = NULL;
+ gomp_mutex_unlock (&lock->lock);
+ }
+}
+
+int
+gomp_test_nest_lock_30 (omp_nest_lock_t *lock)
+{
+ void *me = gomp_icv (true);
+
+ if (lock->owner == me)
+ return ++lock->count;
+
+ if (__sync_bool_compare_and_swap (&lock->lock, 0, 1))
+ {
+ lock->owner = me;
+ lock->count = 1;
+ return 1;
+ }
+
+ return 0;
+}
+
+#ifdef LIBGOMP_GNU_SYMBOL_VERSIONING
+/* gomp_mutex_* can be safely locked in one thread and
+ unlocked in another thread, so the OpenMP 2.5 and OpenMP 3.0
+ non-nested locks can be the same. */
+strong_alias (gomp_init_lock_30, gomp_init_lock_25)
+strong_alias (gomp_destroy_lock_30, gomp_destroy_lock_25)
+strong_alias (gomp_set_lock_30, gomp_set_lock_25)
+strong_alias (gomp_unset_lock_30, gomp_unset_lock_25)
+strong_alias (gomp_test_lock_30, gomp_test_lock_25)
+
+/* The external recursive omp_nest_lock_25_t form requires additional work. */
+
+/* We need an integer to uniquely identify this thread. Most generally
+ this is the thread's TID, which ideally we'd get this straight from
+ the TLS block where glibc keeps it. Unfortunately, we can't get at
+ that directly.
+
+ If we don't support (or have disabled) TLS, one function call is as
+ good (or bad) as any other. Use the syscall all the time.
+
+ On an ILP32 system (defined here as not LP64), we can make do with
+ any thread-local pointer. Ideally we'd use the TLS base address,
+ since that requires the least amount of arithmetic, but that's not
+ always available directly. Make do with the gomp_thread pointer
+ since it's handy. */
+
+# if !defined (HAVE_TLS)
+static inline int gomp_tid (void)
+{
+ return syscall (SYS_gettid);
+}
+# elif !defined(__LP64__)
+static inline int gomp_tid (void)
+{
+ return (int) gomp_thread ();
+}
+# else
+static __thread int tid_cache;
+static inline int gomp_tid (void)
+{
+ int tid = tid_cache;
+ if (__builtin_expect (tid == 0, 0))
+ tid_cache = tid = syscall (SYS_gettid);
+ return tid;
+}
+# endif
+
+
+void
+gomp_init_nest_lock_25 (omp_nest_lock_25_t *lock)
+{
+ memset (lock, 0, sizeof (lock));
+}
+
+void
+gomp_destroy_nest_lock_25 (omp_nest_lock_25_t *lock)
+{
+}
+
+void
+gomp_set_nest_lock_25 (omp_nest_lock_25_t *lock)
+{
+ int otid, tid = gomp_tid ();
+
+ while (1)
+ {
+ otid = __sync_val_compare_and_swap (&lock->owner, 0, tid);
+ if (otid == 0)
+ {
+ lock->count = 1;
+ return;
+ }
+ if (otid == tid)
+ {
+ lock->count++;
+ return;
+ }
+
+ do_wait (&lock->owner, otid);
+ }
+}
+
+void
+gomp_unset_nest_lock_25 (omp_nest_lock_25_t *lock)
+{
+ /* ??? Validate that we own the lock here. */
+
+ if (--lock->count == 0)
+ {
+ __sync_lock_release (&lock->owner);
+ futex_wake (&lock->owner, 1);
+ }
+}
+
+int
+gomp_test_nest_lock_25 (omp_nest_lock_25_t *lock)
+{
+ int otid, tid = gomp_tid ();
+
+ otid = __sync_val_compare_and_swap (&lock->owner, 0, tid);
+ if (otid == 0)
+ {
+ lock->count = 1;
+ return 1;
+ }
+ if (otid == tid)
+ return ++lock->count;
+
+ return 0;
+}
+
+omp_lock_symver (omp_init_lock)
+omp_lock_symver (omp_destroy_lock)
+omp_lock_symver (omp_set_lock)
+omp_lock_symver (omp_unset_lock)
+omp_lock_symver (omp_test_lock)
+omp_lock_symver (omp_init_nest_lock)
+omp_lock_symver (omp_destroy_nest_lock)
+omp_lock_symver (omp_set_nest_lock)
+omp_lock_symver (omp_unset_nest_lock)
+omp_lock_symver (omp_test_nest_lock)
+
+#else
+
+ialias (omp_init_lock)
+ialias (omp_init_nest_lock)
+ialias (omp_destroy_lock)
+ialias (omp_destroy_nest_lock)
+ialias (omp_set_lock)
+ialias (omp_set_nest_lock)
+ialias (omp_unset_lock)
+ialias (omp_unset_nest_lock)
+ialias (omp_test_lock)
+ialias (omp_test_nest_lock)
+
+#endif