Implement __sync_fetch_and_add_4 if necessary.

From-SVN: r169820

libgo/config.h.in

@@ -43,6 +43,10 @@
    function for uint32 */
 #undef HAVE_SYNC_BOOL_COMPARE_AND_SWAP_4
 
+/* Define to 1 if the compiler provides the __sync_fetch_and_add function for
+   uint32 */
+#undef HAVE_SYNC_FETCH_AND_ADD_4
+
 /* Define to 1 if you have the <syscall.h> header file. */
 #undef HAVE_SYSCALL_H
 

libgo/configure

@@ -14206,6 +14206,35 @@ $as_echo "#define HAVE_SYNC_BOOL_COMPARE_AND_SWAP_4 1" >>confdefs.h
 
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for __sync_fetch_and_add_4" >&5
+$as_echo_n "checking for __sync_fetch_and_add_4... " >&6; }
+if test "${libgo_cv_func___sync_fetch_and_add_4+set}" = set; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+typedef unsigned int uint32  __attribute__ ((mode (SI)));
+uint32 i;
+int main() { return __sync_fetch_and_add (&i, 1); }
+
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  libgo_cv_func___sync_fetch_and_add_4=yes
+else
+  libgo_cv_func___sync_fetch_and_add_4=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libgo_cv_func___sync_fetch_and_add_4" >&5
+$as_echo "$libgo_cv_func___sync_fetch_and_add_4" >&6; }
+if test "$libgo_cv_func___sync_fetch_and_add_4" = "yes"; then
+
+$as_echo "#define HAVE_SYNC_FETCH_AND_ADD_4 1" >>confdefs.h
+
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether compiler supports -minline-all-stringops" >&5
 $as_echo_n "checking whether compiler supports -minline-all-stringops... " >&6; }
 if test "${libgo_cv_c_stringops+set}" = set; then :

libgo/configure.ac

@@ -396,6 +396,20 @@ if test "$libgo_cv_func___sync_bool_compare_and_swap_4" = "yes"; then
     [Define to 1 if the compiler provides the __sync_bool_compare_and_swap function for uint32])
 fi
 
+AC_CACHE_CHECK([for __sync_fetch_and_add_4],
+[libgo_cv_func___sync_fetch_and_add_4],
+[AC_LINK_IFELSE([
+typedef unsigned int uint32  __attribute__ ((mode (SI)));
+uint32 i;
+int main() { return __sync_fetch_and_add (&i, 1); }
+],
+[libgo_cv_func___sync_fetch_and_add_4=yes],
+[libgo_cv_func___sync_fetch_and_add_4=no])])
+if test "$libgo_cv_func___sync_fetch_and_add_4" = "yes"; then
+  AC_DEFINE(HAVE_SYNC_FETCH_AND_ADD_4, 1,
+    [Define to 1 if the compiler provides the __sync_fetch_and_add function for uint32])
+fi
+
 dnl For x86 we want to use the -minline-all-stringops option to avoid
 dnl forcing a stack split when calling memcpy and friends.
 AC_CACHE_CHECK([whether compiler supports -minline-all-stringops],

libgo/runtime/go-semacquire.c

@@ -117,3 +117,35 @@ semrelease (uint32 *addr)
       __go_assert (i == 0);
     }
 }
+
+
+#ifndef HAVE_SYNC_FETCH_AND_ADD_4
+
+/* For targets which don't have the required sync support.  Really
+   this should be provided by gcc itself.  FIXME.  */
+
+static pthread_mutex_t sync_lock = PTHREAD_MUTEX_INITIALIZER;
+
+uint32
+__sync_fetch_and_add_4(uint32*, uint32)
+  __attribute__((visibility("hidden")));
+
+uint32
+__sync_fetch_and_add_4(uint32* ptr, uint32 add)
+{
+  int i;
+  uint32 ret;
+
+  i = pthread_mutex_lock(&sync_lock);
+  __go_assert(i == 0);
+
+  ret = *ptr;
+  *ptr += add;
+
+  i = pthread_mutex_unlock(&sync_lock);
+  __go_assert(i == 0);
+
+  return ret;
+}
+
+#endif