From: Johannes Berg <johannes.berg@xxxxxxxxx> Subject: kernel.h: hide __is_constexpr() from sparse __is_constexpr() is a work of art, understandable only to the most respected wizards of C. Even sparse doesn't seem to belong to that group and warns that there's an "expression using sizeof(void)". Just hide the definition from sparse and pretend it's always true. Link: http://lkml.kernel.org/r/20181109093534.15121-2-johannes@xxxxxxxxxxxxxxxx Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/include/linux/kernel.h~kernelh-hide-__is_constexpr-from-sparse +++ a/include/linux/kernel.h @@ -844,6 +844,7 @@ static inline void ftrace_dump(enum ftra #define __typecheck(x, y) \ (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1))) +#ifndef __CHECKER__ /* * This returns a constant expression while determining if an argument is * a constant expression, most importantly without evaluating the argument. @@ -851,6 +852,13 @@ static inline void ftrace_dump(enum ftra */ #define __is_constexpr(x) \ (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) +#else +/* + * We don't really care about the check when running sparse and the + * above expression causes a warning due to sizeof(void). + */ +#define __is_constexpr(x) 1 +#endif #define __no_side_effects(x, y) \ (__is_constexpr(x) && __is_constexpr(y)) _
