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, 24 insertions, 0 deletions

diff --git a/configure.in b/configure.in
index 1ad79c398fb..e5d228cc017 100644
--- a/configure.in
+++ b/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],