| /* atomic.c -- Support for atomic functions if not present. |
| Copyright (C) 2013-2020 Free Software Foundation, Inc. |
| Written by Ian Lance Taylor, Google. |
| |
| 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. |
| |
| (3) The name of the author may not be used to |
| endorse or promote products derived from this software without |
| specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. */ |
| |
| #include "config.h" |
| |
| #include <sys/types.h> |
| |
| #include "backtrace.h" |
| #include "backtrace-supported.h" |
| #include "internal.h" |
| |
| /* This file holds implementations of the atomic functions that are |
| used if the host compiler has the sync functions but not the atomic |
| functions, as is true of versions of GCC before 4.7. */ |
| |
| #if !defined (HAVE_ATOMIC_FUNCTIONS) && defined (HAVE_SYNC_FUNCTIONS) |
| |
| /* Do an atomic load of a pointer. */ |
| |
| void * |
| backtrace_atomic_load_pointer (void *arg) |
| { |
| void **pp; |
| void *p; |
| |
| pp = (void **) arg; |
| p = *pp; |
| while (!__sync_bool_compare_and_swap (pp, p, p)) |
| p = *pp; |
| return p; |
| } |
| |
| /* Do an atomic load of an int. */ |
| |
| int |
| backtrace_atomic_load_int (int *p) |
| { |
| int i; |
| |
| i = *p; |
| while (!__sync_bool_compare_and_swap (p, i, i)) |
| i = *p; |
| return i; |
| } |
| |
| /* Do an atomic store of a pointer. */ |
| |
| void |
| backtrace_atomic_store_pointer (void *arg, void *p) |
| { |
| void **pp; |
| void *old; |
| |
| pp = (void **) arg; |
| old = *pp; |
| while (!__sync_bool_compare_and_swap (pp, old, p)) |
| old = *pp; |
| } |
| |
| /* Do an atomic store of a size_t value. */ |
| |
| void |
| backtrace_atomic_store_size_t (size_t *p, size_t v) |
| { |
| size_t old; |
| |
| old = *p; |
| while (!__sync_bool_compare_and_swap (p, old, v)) |
| old = *p; |
| } |
| |
| /* Do an atomic store of a int value. */ |
| |
| void |
| backtrace_atomic_store_int (int *p, int v) |
| { |
| size_t old; |
| |
| old = *p; |
| while (!__sync_bool_compare_and_swap (p, old, v)) |
| old = *p; |
| } |
| |
| #endif |