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114 lines
2.9 KiB
C
114 lines
2.9 KiB
C
/* atomic.c -- Support for atomic functions if not present.
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Copyright (C) 2013-2020 Free Software Foundation, Inc.
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Written by Ian Lance Taylor, Google.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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(1) Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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(2) Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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(3) The name of the author may not be used to
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endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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#include "config.h"
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#include <sys/types.h>
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#include "backtrace.h"
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#include "backtrace-supported.h"
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#include "internal.h"
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/* This file holds implementations of the atomic functions that are
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used if the host compiler has the sync functions but not the atomic
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functions, as is true of versions of GCC before 4.7. */
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#if !defined (HAVE_ATOMIC_FUNCTIONS) && defined (HAVE_SYNC_FUNCTIONS)
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/* Do an atomic load of a pointer. */
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void *
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backtrace_atomic_load_pointer (void *arg)
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{
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void **pp;
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void *p;
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pp = (void **) arg;
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p = *pp;
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while (!__sync_bool_compare_and_swap (pp, p, p))
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p = *pp;
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return p;
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}
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/* Do an atomic load of an int. */
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int
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backtrace_atomic_load_int (int *p)
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{
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int i;
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i = *p;
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while (!__sync_bool_compare_and_swap (p, i, i))
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i = *p;
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return i;
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}
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/* Do an atomic store of a pointer. */
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void
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backtrace_atomic_store_pointer (void *arg, void *p)
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{
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void **pp;
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void *old;
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pp = (void **) arg;
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old = *pp;
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while (!__sync_bool_compare_and_swap (pp, old, p))
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old = *pp;
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}
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/* Do an atomic store of a size_t value. */
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void
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backtrace_atomic_store_size_t (size_t *p, size_t v)
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{
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size_t old;
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old = *p;
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while (!__sync_bool_compare_and_swap (p, old, v))
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old = *p;
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}
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/* Do an atomic store of a int value. */
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void
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backtrace_atomic_store_int (int *p, int v)
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{
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size_t old;
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old = *p;
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while (!__sync_bool_compare_and_swap (p, old, v))
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old = *p;
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}
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#endif
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