On 17/10/2023 08:09, Jan Beulich wrote:
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) \
You're probably right. I was wondering the same thing when replacing the
code with
BUILD_BUG_ON.
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)