On 12.10.2023 17:28, Nicola Vetrini wrote:
> BUILD_BUG_ON is the preferred way to induce a build error
> upon statically determined incorrect conditions.
>
> This also fixes a MISRA C:2012 Rule 10.1 violation in the
> previous formulation.
>
> Signed-off-by: Nicola Vetrini <nicola.vetr...@bugseng.com>
Hmm, looking back it's indeed not clear why I didn't use BUILD_BUG_ON() right
away. Perhaps just to avoid inline functions when things can be done without.
And/or because originally the macros were intended to be usable in function
bodies, not (just) at file scope. However, ...
> --- a/xen/include/xen/compat.h
> +++ b/xen/include/xen/compat.h
> @@ -151,12 +151,20 @@ CHECK_NAME_(k, n, T)(k xen_ ## n *x, \
> return x == c; \
> }
>
> -#define CHECK_SIZE(name) \
> - typedef int CHECK_NAME(name, S)[1 - (sizeof(xen_ ## name ## _t) != \
> - sizeof(compat_ ## name ## _t)) * 2]
> +#define CHECK_SIZE(name) \
> +static inline void __maybe_unused CHECK_SIZE_##name(void) \
> +{ \
> + typedef int CHECK_NAME(name, S)[1]; \
... what's this and ...
> + BUILD_BUG_ON(sizeof(xen_ ## name ## _t) != \
> + sizeof(compat_ ## name ## _t)); \
> +}
> #define CHECK_SIZE_(k, n) \
> - typedef int CHECK_NAME_(k, n, S)[1 - (sizeof(k xen_ ## n) != \
> - sizeof(k compat_ ## n)) * 2]
> +static inline void __maybe_unused CHECK_SIZE_##k_##n(void) \
> +{ \
> + typedef int CHECK_NAME_(k, n, S)[1]; \
... this needed for? The types aren't used anywhere afaict.
Jan
> + BUILD_BUG_ON(sizeof(k xen_ ## n) != \
> + sizeof(k compat_ ## n)); \
> +}
>
> #define CHECK_FIELD_COMMON(name, t, f) \
> static inline int __maybe_unused name(xen_ ## t ## _t *x, compat_ ## t ## _t
> *c) \
