[PATCH v2] ubsan: don't mark __ubsan_handle_builtin_unreachable as noreturn

[Andrey Ryabinin]

From: Arnd Bergmann <arnd@xxxxxxxx>

gcc-8 complains about the prototype for this function:

lib/ubsan.c:432:1: error: ignoring attribute 'noreturn' in declaration of a built-in function '__ubsan_handle_builtin_unreachable' because it conflicts with attribute 'const' [-Werror=attributes]

This is actually a GCC's bug. In GCC internals
__ubsan_handle_builtin_unreachable() declared with both 'noreturn' and
'const' attributes instead of only 'noreturn':
   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84210

Workaround this by removing the noreturn attribute.

[aryabinin: Add information about GCC bug in changelog]
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
---
 lib/ubsan.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/ubsan.c b/lib/ubsan.c
index 59fee96c29a0..e4162f59a81c 100644
--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -427,8 +427,7 @@ void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
 EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
 
 
-void __noreturn
-__ubsan_handle_builtin_unreachable(struct unreachable_data *data)
+void __ubsan_handle_builtin_unreachable(struct unreachable_data *data)
 {
 	unsigned long flags;
 
-- 
2.18.1