diff options
Diffstat (limited to 'include/linux/build_bug.h')
| -rw-r--r-- | include/linux/build_bug.h | 40 |
1 files changed, 34 insertions, 6 deletions
diff --git a/include/linux/build_bug.h b/include/linux/build_bug.h index faeec7433aab..2cfbb4c65c78 100644 --- a/include/linux/build_bug.h +++ b/include/linux/build_bug.h @@ -4,17 +4,17 @@ #include <linux/compiler.h> -#ifdef __CHECKER__ -#define BUILD_BUG_ON_ZERO(e) (0) -#else /* __CHECKER__ */ /* * 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 + * result (of value 0 and type int), so the expression can be used * e.g. in a structure initializer (or where-ever else comma expressions * aren't permitted). + * + * Take an error message as an optional second argument. If omitted, + * default to the stringification of the tested expression. */ -#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:(-!!(e)); })) -#endif /* __CHECKER__ */ +#define BUILD_BUG_ON_ZERO(e, ...) \ + __BUILD_BUG_ON_ZERO_MSG(e, ##__VA_ARGS__, #e " is true") /* Force a compilation error if a constant expression is not a power of 2 */ #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \ @@ -58,4 +58,32 @@ */ #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") +/** + * static_assert - check integer constant expression at build time + * + * static_assert() is a wrapper for the C11 _Static_assert, with a + * little macro magic to make the message optional (defaulting to the + * stringification of the tested expression). + * + * Contrary to BUILD_BUG_ON(), static_assert() can be used at global + * scope, but requires the expression to be an integer constant + * expression (i.e., it is not enough that __builtin_constant_p() is + * true for expr). + * + * Also note that BUILD_BUG_ON() fails the build if the condition is + * true, while static_assert() fails the build if the expression is + * false. + */ +#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr) +#define __static_assert(expr, msg, ...) _Static_assert(expr, msg) + + +/* + * Compile time check that field has an expected offset + */ +#define ASSERT_STRUCT_OFFSET(type, field, expected_offset) \ + BUILD_BUG_ON_MSG(offsetof(type, field) != (expected_offset), \ + "Offset of " #field " in " #type " has changed.") + + #endif /* _LINUX_BUILD_BUG_H */ |