Added support for _Noreturn function specifier (ISO C11).

  * acinclude.m4: define MPFR_HAVE_NORETURN if _Noreturn is supported.
  * src/mpfr-impl.h: use _Noreturn when MPFR_HAVE_NORETURN is defined.
Tested with GCC 4.6 (no _Noreturn) and 4.7 (supports _Noreturn).

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@8156 280ebfd0-de03-0410-8827-d642c229c3f4

2 files changed, 20 insertions, 6 deletions

diff --git a/acinclude.m4 b/acinclude.m4
index cfe5e283a..6109d3750 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -137,6 +137,15 @@ AC_CHECK_TYPE( [union fpc_csr],
 #endif
 ])
 
+dnl Check for _Noreturn function specifier (ISO C11)
+AC_CACHE_CHECK([for _Noreturn], mpfr_cv_have_noreturn, [
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[_Noreturn void foo(int);]])],
+    mpfr_cv_have_noreturn=yes, mpfr_cv_have_noreturn=no)
+])
+if test "$mpfr_cv_have_noreturn" = "yes"; then
+  AC_DEFINE(MPFR_HAVE_NORETURN,1,[Define if the _Noreturn function specifier is supported.])
+fi
+
 dnl Check for fesetround
 AC_CACHE_CHECK([for fesetround], mpfr_cv_have_fesetround, [
 saved_LIBS="$LIBS"
diff --git a/src/mpfr-impl.h b/src/mpfr-impl.h
index f8434fb16..61211cfa7 100644
--- a/src/mpfr-impl.h
+++ b/src/mpfr-impl.h
@@ -224,13 +224,19 @@ typedef __gmp_const mp_limb_t *mpfr_limb_srcptr;
 # error "Can't compute log2(GMP_NUMB_BITS)"
 #endif
 
+#if defined(MPFR_HAVE_NORETURN)
+/* _Noreturn is specified by ISO C11 (Section 6.7.4);
+   in GCC, it is supported as of version 4.7. */
+# define MPFR_NORETURN _Noreturn
+#elif __MPFR_GNUC(3,0) || __MPFR_ICC(8,1,0)
+# define MPFR_NORETURN __attribute__ ((noreturn))
+#else
+# define MPFR_NORETURN
+#endif
+
 #if __MPFR_GNUC(3,0) || __MPFR_ICC(8,1,0)
-/* For the future: N1478: Supporting the 'noreturn' property in C1x
-   http://www.open-std.org/JTC1/SC22/WG14/www/docs/n1478.htm */
-# define MPFR_NORETURN_ATTR __attribute__ ((noreturn))
 # define MPFR_CONST_ATTR    __attribute__ ((const))
 #else
-# define MPFR_NORETURN_ATTR
 # define MPFR_CONST_ATTR
 #endif
 
@@ -1928,8 +1934,7 @@ __MPFR_DECLSPEC void mpfr_dump_mant _MPFR_PROTO ((const mp_limb_t *,
 __MPFR_DECLSPEC int mpfr_round_near_x _MPFR_PROTO ((mpfr_ptr, mpfr_srcptr,
                                                     mpfr_uexp_t, int,
                                                     mpfr_rnd_t));
-__MPFR_DECLSPEC void mpfr_abort_prec_max _MPFR_PROTO ((void))
-       MPFR_NORETURN_ATTR;
+__MPFR_DECLSPEC MPFR_NORETURN void mpfr_abort_prec_max _MPFR_PROTO ((void));
 
 __MPFR_DECLSPEC void mpfr_rand_raw _MPFR_PROTO((mpfr_limb_ptr, gmp_randstate_t,
                                                 mpfr_prec_t));