There are theoretical concerns that some compilers might not trigger build failures on attempts to define an array of size (x ? -1 : 1) where x is a variable and make it a variable sized array instead. Let rewrite using a struct with a negative bit field size instead as there are no dynamic bit field sizes. This is similar to what Linux does.
Signed-off-by: Michael S. Tsirkin <m...@redhat.com> Reviewed-by: Eric Blake <ebl...@redhat.com> Reviewed-by: Markus Armbruster <arm...@redhat.com> --- include/qemu/compiler.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 7512082..1da500e 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -85,9 +85,12 @@ #define typeof_field(type, field) typeof(((type *)0)->field) #define type_check(t1,t2) ((t1*)0 - (t2*)0) -#define QEMU_BUILD_BUG_ON(x) \ - typedef char glue(qemu_build_bug_on__, __LINE__)[(x) ? -1 : 1] \ - __attribute__((unused)) +#define QEMU_BUILD_BUG_ON_STRUCT(x) \ + struct { \ + int:(x) ? -1 : 1; \ + } +#define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \ + glue(qemu_build_bug_on__, __LINE__) __attribute__((unused)) #if defined __GNUC__ # if !QEMU_GNUC_PREREQ(4, 4) -- MST