| Message ID | 20180224154033.29559-2-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3,1/7] compiler: Add QEMU_BUILD_BUG_MSG() macro | expand |
On 02/24/2018 09:40 AM, Max Reitz wrote: > _Static_assert() allows us to specify messages, and that may come in > handy. Even without _Static_assert(), encouraging developers to put a > helpful message next to the QEMU_BUILD_BUG_* may make debugging easier > whenever it breaks. > > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > include/qemu/compiler.h | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > Reviewed-by: Eric Blake <eblake@redhat.com>
On Sat 24 Feb 2018 04:40:27 PM CET, Max Reitz wrote: > _Static_assert() allows us to specify messages, and that may come in > handy. Even without _Static_assert(), encouraging developers to put a > helpful message next to the QEMU_BUILD_BUG_* may make debugging easier > whenever it breaks. > > Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Berto
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 2cbe6a4f16..9f762695d1 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -82,15 +82,21 @@ int:(x) ? -1 : 1; \ } +/* QEMU_BUILD_BUG_MSG() emits the message given if _Static_assert is + * supported; otherwise, it will be omitted from the compiler error + * message (but as it remains present in the source code, it can still + * be useful when debugging). */ #if defined(CONFIG_STATIC_ASSERT) -#define QEMU_BUILD_BUG_ON(x) _Static_assert(!(x), "not expecting: " #x) +#define QEMU_BUILD_BUG_MSG(x, msg) _Static_assert(!(x), msg) #elif defined(__COUNTER__) -#define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \ +#define QEMU_BUILD_BUG_MSG(x, msg) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \ glue(qemu_build_bug_on__, __COUNTER__) __attribute__((unused)) #else -#define QEMU_BUILD_BUG_ON(x) +#define QEMU_BUILD_BUG_MSG(x, msg) #endif +#define QEMU_BUILD_BUG_ON(x) QEMU_BUILD_BUG_MSG(x, "not expecting: " #x) + #define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \ sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)))
_Static_assert() allows us to specify messages, and that may come in handy. Even without _Static_assert(), encouraging developers to put a helpful message next to the QEMU_BUILD_BUG_* may make debugging easier whenever it breaks. Signed-off-by: Max Reitz <mreitz@redhat.com> --- include/qemu/compiler.h | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)