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Diffstat (limited to 'contrib/libcxxrt/guard.cc')
-rw-r--r-- | contrib/libcxxrt/guard.cc | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/contrib/libcxxrt/guard.cc b/contrib/libcxxrt/guard.cc index f236053..b14a13b 100644 --- a/contrib/libcxxrt/guard.cc +++ b/contrib/libcxxrt/guard.cc @@ -1,3 +1,29 @@ +/* + * Copyright 2010-2012 PathScale, Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS + * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; + * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR + * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF + * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + /** * guard.cc: Functions for thread-safe static initialisation. * @@ -103,6 +129,10 @@ extern "C" int __cxa_guard_acquire(volatile int64_t *guard_object) // the lock at the same time. while (!__sync_bool_compare_and_swap_4(lock, 0, 1)) { + if (1 == ((*guard_object) >> 56)) + { + break; + } sched_yield(); } // We have to test the guard again, in case another thread has performed |