diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2017-01-19 22:56:14 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2017-02-01 03:37:17 +0200 |
| commit | f291887e8eef5d37d31484638f6e62401b4b99a2 (patch) | |
| tree | 5263e8d16a5a9500febaa3de574bb3afd801c808 | |
| parent | 60abf0a5e05134187e274ce5f32524ccf0cae1a6 (diff) | |
compiler: rework BUG_ON using a struct
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 <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
| -rw-r--r-- | include/qemu/compiler.h | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 77b9ce3979..057639af43 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -85,10 +85,14 @@ #define typeof_field(type, field) typeof(((type *)0)->field) #define type_check(t1,t2) ((t1*)0 - (t2*)0) +#define QEMU_BUILD_BUG_ON_STRUCT(x) \ + struct { \ + int:(x) ? -1 : 1; \ + } + #ifdef __COUNTER__ -#define QEMU_BUILD_BUG_ON(x) \ - typedef char glue(qemu_build_bug_on__, __COUNTER__)[(x) ? -1 : 1] \ - __attribute__((unused)) +#define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \ + glue(qemu_build_bug_on__, __COUNTER__) __attribute__((unused)) #else #define QEMU_BUILD_BUG_ON(x) #endif |