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.

configure.in

@@ -1688,6 +1688,30 @@ case "$with_atomic_ops" in
    *) AC_MSG_ERROR(["$with_atomic_ops" is not a valid value for --with-atomic-ops]) ;;
 esac
 
+AC_CACHE_CHECK([whether the compiler provides atomic builtins],
+               [mysql_cv_gcc_atomic_builtins], [AC_TRY_RUN([
+  int main()
+  {
+    int foo= -10; int bar= 10;
+    if (!__sync_fetch_and_add(&foo, bar) || foo)
+      return -1;
+    bar= __sync_lock_test_and_set(&foo, bar);
+    if (bar || foo != 10)
+      return -1;
+    bar= __sync_val_compare_and_swap(&bar, foo, 15);
+    if (bar)
+      return -1;
+    return 0;
+  }
+], [mysql_cv_gcc_atomic_builtins=yes],
+   [mysql_cv_gcc_atomic_builtins=no],
+   [mysql_cv_gcc_atomic_builtins=no])])
+
+if test "x$mysql_cv_gcc_atomic_builtins" = xyes; then
+  AC_DEFINE(HAVE_GCC_ATOMIC_BUILTINS, 1,
+            [Define to 1 if compiler provides atomic builtins.])
+fi
+
 # Force static compilation to avoid linking problems/get more speed
 AC_ARG_WITH(mysqld-ldflags,
     [  --with-mysqld-ldflags   Extra linking arguments for mysqld],

include/atomic/gcc_builtins.h

+/* 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

include/atomic/nolock.h

@@ -13,7 +13,7 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 
-#if defined(__i386__) || defined(_M_IX86)
+#if defined(__i386__) || defined(_M_IX86) || defined(HAVE_GCC_ATOMIC_BUILTINS)
 
 #ifdef MY_ATOMIC_MODE_DUMMY
 #  define LOCK ""
@@ -21,7 +21,9 @@
 #  define LOCK "lock"
 #endif
 
-#ifdef __GNUC__
+#ifdef HAVE_GCC_ATOMIC_BUILTINS
+#include "gcc_builtins.h"
+#elif __GNUC__
 #include "x86-gcc.h"
 #elif defined(_MSC_VER)
 #include "x86-msvc.h"