Bug#33728 Atomic builtins

Use compiler provided atomic builtins as a 'backend' for
MySQL's atomic primitives. The builtins are available on
a handful of platforms and compilers.


configure.in:
  Check if the compiler provides atomic builtins and
  that __sync_lock_test_and_set stores the correct value.
include/atomic/nolock.h:
  Use the atomic builtins if available.
include/atomic/gcc_builtins.h:
  Implement the atomic ADD, SWAP, CAS, STORE (or operation
  optimized away) and LOAD primitives using atomic builtins
  provided by the compiler.

1 files changed, 33 insertions, 0 deletions

diff --git a/include/atomic/gcc_builtins.h b/include/atomic/gcc_builtins.h
new file mode 100644
index 00000000000..509701b30a5
--- /dev/null
+++ b/include/atomic/gcc_builtins.h
@@ -0,0 +1,33 @@
+/* Copyright (C) 2008 MySQL AB
+
+   This program 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; version 2 of the License.
+
+   This program 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.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#define make_atomic_add_body(S)                     \
+  v= __sync_fetch_and_add(a, v);
+#define make_atomic_swap_body(S)                    \
+  v= __sync_lock_test_and_set(a, v);
+#define make_atomic_cas_body(S)                     \
+  int ## S sav;                                     \
+  sav= __sync_val_compare_and_swap(a, *cmp, set);   \
+  if (!(ret= (sav == *cmp))) *cmp= sav;
+
+#ifdef MY_ATOMIC_MODE_DUMMY
+#define make_atomic_load_body(S)   ret= *a
+#define make_atomic_store_body(S)  *a= v
+#else
+#define make_atomic_load_body(S)                    \
+  ret= __sync_fetch_and_or(a, 0);
+#define make_atomic_store_body(S)                   \
+  (void) __sync_lock_test_and_set(a, v);
+#endif