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author | Jan Beulich <jbeulich@suse.com> | 2012-07-27 09:59:25 +0200 |
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committer | Jan Beulich <jbeulich@suse.com> | 2012-07-27 09:59:25 +0200 |
commit | 2621048598e9c71a44811add31d8d7530d1ed056 (patch) | |
tree | 2f3f705a24b37ecc63697a7e491d8fa43fd6ff69 | |
parent | 7e45ec6a46a9c2026e6148c0020a92ce29b5d12e (diff) | |
download | xen-2621048598e9c71a44811add31d8d7530d1ed056.tar.gz xen-2621048598e9c71a44811add31d8d7530d1ed056.tar.bz2 xen-2621048598e9c71a44811add31d8d7530d1ed056.zip |
use C11's _Static_assert() for BUILD_BUG_ON etc when available
This produces a more meaningful compiler diagnostic in case it happens
to trigger.
As a minor piece of cleanup, at once also use BUILD_BUG_ON_ZERO() to
actually define BUILD_BUG_ON() in the legacy case, slightly reducing
redundancy.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
-rw-r--r-- | xen/include/xen/lib.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h index 36b4c7f12d..1919ed7d93 100644 --- a/xen/include/xen/lib.h +++ b/xen/include/xen/lib.h @@ -14,14 +14,20 @@ void __warn(char *file, int line); #define BUG_ON(p) do { if (unlikely(p)) BUG(); } while (0) #define WARN_ON(p) do { if (unlikely(p)) WARN(); } while (0) +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6) /* Force a compilation error if condition is true */ -#define BUILD_BUG_ON(condition) ((void)sizeof(struct { int:-!!(condition); })) +#define BUILD_BUG_ON(cond) ({ _Static_assert(!(cond), "!(" #cond ")"); }) /* Force a compilation error if condition is true, but also produce a result (of value 0 and type size_t), so the expression can be used e.g. in a structure initializer (or where-ever else comma expressions aren't permitted). */ -#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); })) +#define BUILD_BUG_ON_ZERO(cond) \ + sizeof(struct { _Static_assert(!(cond), "!(" #cond ")"); }) +#else +#define BUILD_BUG_ON_ZERO(cond) sizeof(struct { int:-!!(cond); }) +#define BUILD_BUG_ON(cond) ((void)BUILD_BUG_ON_ZERO(cond)) +#endif #ifndef assert_failed #define assert_failed(p) \ |