utils: Enable __atomic* built-ins based on the GCC version
authorTobias Brunner <tobias@strongswan.org>
Fri, 2 May 2014 15:58:26 +0000 (17:58 +0200)
committerAndreas Steffen <andreas.steffen@strongswan.org>
Sun, 4 May 2014 17:16:46 +0000 (19:16 +0200)
This solves a problem with GNAT when compiling charon-tkm as __atomic*
built-ins are only provided in GCC 4.7 and newer.

Currently GNAT 4.6 and GCC 4.7.2 is shipped with Debian wheezy (stable),
as used in the testing environment.  So while the configure script correctly
detected the __atomic* built-ins, and defined HAVE_GCC_ATOMIC_OPERATIONS,
this define turned out to be incorrect when charon-tkm was later built
with GNAT.

configure.ac
src/libstrongswan/utils/utils.h

index 4aae79d..1bd68d6 100644 (file)
@@ -668,25 +668,6 @@ AC_COMPILE_IFELSE(
        [AC_MSG_RESULT([no])]
 )
 
-AC_MSG_CHECKING([for GCC __atomic operations])
-AC_RUN_IFELSE([AC_LANG_SOURCE(
-       [[
-                       int main() {
-                       int ref = 1, val;
-                       __atomic_fetch_add(&ref, 1, __ATOMIC_RELAXED);
-                       val = __atomic_sub_fetch(&ref, 1, __ATOMIC_RELAXED);
-                       __atomic_compare_exchange_n(&ref, &val, 0, 0, __ATOMIC_RELAXED,
-                                                                               __ATOMIC_RELAXED);
-                       return ref;
-               }
-       ]])],
-       [AC_MSG_RESULT([yes]);
-        AC_DEFINE([HAVE_GCC_ATOMIC_OPERATIONS], [],
-                  [have GCC __atomic_* operations])],
-       [AC_MSG_RESULT([no])],
-       [AC_MSG_RESULT([no])]
-)
-
 AC_MSG_CHECKING([for GCC __sync operations])
 AC_RUN_IFELSE([AC_LANG_SOURCE(
        [[
index 8f91e84..75b31ec 100644 (file)
@@ -748,6 +748,13 @@ static inline size_t round_down(size_t size, size_t alignment)
  */
 typedef u_int refcount_t;
 
+/* use __atomic* built-ins with GCC 4.7 and newer */
+#ifdef __GNUC__
+# if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ > 6))
+#  define HAVE_GCC_ATOMIC_OPERATIONS
+# endif
+#endif
+
 #ifdef HAVE_GCC_ATOMIC_OPERATIONS
 
 #define ref_get(ref) __atomic_add_fetch(ref, 1, __ATOMIC_RELAXED)