Recent compilers support __has_attribute() to check if a certain compiler attribute is supported. Unfortunately we have to first check if __has_attribute is supported in the first place and then if a specific attribute is present. These two checks can't be folded into a single condition as that would lead to errors.
Nesting the two conditions like below works, but becomes ugly as soon as #else blocks are used as those need to be duplicated for both levels of #if.
#if defined __has_attribute # if __has_attribute (nonnull) # define ATTR_NONNULL __attribute__ ((nonnull)) # endif #endif
Introduce a new helper which makes the usage of __has_attribute() nicer and migrate the current user to it.
Signed-off-by: Thomas Weißschuh linux@weissschuh.net --- tools/include/nolibc/compiler.h | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/tools/include/nolibc/compiler.h b/tools/include/nolibc/compiler.h index beddc3665d69..1730d0454a55 100644 --- a/tools/include/nolibc/compiler.h +++ b/tools/include/nolibc/compiler.h @@ -6,20 +6,22 @@ #ifndef _NOLIBC_COMPILER_H #define _NOLIBC_COMPILER_H
+#if defined(__has_attribute) +# define __nolibc_has_attribute(attr) __has_attribute(attr) +#else +# define __nolibc_has_attribute(attr) 0 +#endif + #if defined(__SSP__) || defined(__SSP_STRONG__) || defined(__SSP_ALL__) || defined(__SSP_EXPLICIT__)
#define _NOLIBC_STACKPROTECTOR
#endif /* defined(__SSP__) ... */
-#if defined(__has_attribute) -# if __has_attribute(no_stack_protector) -# define __no_stack_protector __attribute__((no_stack_protector)) -# else -# define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector"))) -# endif +#if __nolibc_has_attribute(no_stack_protector) +# define __no_stack_protector __attribute__((no_stack_protector)) #else # define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector"))) -#endif /* defined(__has_attribute) */ +#endif /* __nolibc_has_attribute(no_stack_protector) */
#endif /* _NOLIBC_COMPILER_H */