We can use the __sync builtin atomics also on other architectures than
IA64. GCC 4.7 documentation notes that these builtins are ``legacy'' --
adding support for the newer GCC __atomic atomics should be fairly easy.
---
configure.ac | 13 +++++++++++++
include/libunwind_i.h | 8 ++++----
2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/configure.ac b/configure.ac
index afd63c1..0176c24 100644
--- a/configure.ac
+++ b/configure.ac
@@ -283,6 +283,19 @@ if test x$have__builtin___clear_cache = xyes; then
fi
AC_MSG_RESULT([$have__builtin___clear_cache])
+AC_MSG_CHECKING([for __sync atomics])
+AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM([[]], [[
+ __sync_fetch_and_add((int *)0, 1);
+ ]])],
+ [have_sync_atomics=yes],
+ [have_sync_atomics=no])
+if test x$have_sync_atomics = xyes; then
+ AC_DEFINE([HAVE_SYNC_ATOMICS], [1],
+ [Defined if __sync atomics are available])
+fi
+AC_MSG_RESULT([$have_sync_atomics])
+
CCASFLAGS="${CCASFLAGS} ${CPPFLAGS}"
arch="$target_arch"
diff --git a/include/libunwind_i.h b/include/libunwind_i.h
index f015365..f7e3204 100644
--- a/include/libunwind_i.h
+++ b/include/libunwind_i.h
@@ -99,13 +99,13 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE. */
# define fetch_and_add1(_ptr) AO_fetch_and_add1(_ptr)
# define fetch_and_add(_ptr, value) AO_fetch_and_add(_ptr, value)
# define HAVE_FETCH_AND_ADD
-#else
+#elif defined(HAVE_SYNC_ATOMICS) || defined(HAVE_IA64INTRIN_H)
# ifdef HAVE_IA64INTRIN_H
# include <ia64intrin.h>
-# define fetch_and_add1(_ptr) __sync_fetch_and_add(_ptr, 1)
-# define fetch_and_add(_ptr, value) __sync_fetch_and_add(_ptr, value)
-# define HAVE_FETCH_AND_ADD
# endif
+# define fetch_and_add1(_ptr) __sync_fetch_and_add(_ptr, 1)
+# define fetch_and_add(_ptr, value) __sync_fetch_and_add(_ptr, value)
+# define HAVE_FETCH_AND_ADD
#endif
#define atomic_read(ptr) (*(ptr))
--
1.7.9.5
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