| #ifndef _LINUX_BUILD_BUG_H |
| #define _LINUX_BUILD_BUG_H |
| |
| #include <linux/compiler.h> |
| |
| #ifdef __CHECKER__ |
| #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) (0) |
| #define BUILD_BUG_ON_NOT_POWER_OF_2(n) (0) |
| #define BUILD_BUG_ON_ZERO(e) (0) |
| #define BUILD_BUG_ON_NULL(e) ((void *)0) |
| #define BUILD_BUG_ON_INVALID(e) (0) |
| #define BUILD_BUG_ON_MSG(cond, msg) (0) |
| #define BUILD_BUG_ON(condition) (0) |
| #define BUILD_BUG() (0) |
| #else /* __CHECKER__ */ |
| |
| /* Force a compilation error if a constant expression is not a power of 2 */ |
| #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \ |
| BUILD_BUG_ON(((n) & ((n) - 1)) != 0) |
| #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \ |
| BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0)) |
| |
| /* |
| * 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_NULL(e) ((void *)sizeof(struct { int:(-!!(e)); })) |
| |
| /* |
| * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the |
| * expression but avoids the generation of any code, even if that expression |
| * has side-effects. |
| */ |
| #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e)))) |
| |
| /** |
| * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied |
| * error message. |
| * @condition: the condition which the compiler should know is false. |
| * |
| * See BUILD_BUG_ON for description. |
| */ |
| #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) |
| |
| /** |
| * BUILD_BUG_ON - break compile if a condition is true. |
| * @condition: the condition which the compiler should know is false. |
| * |
| * If you have some code which relies on certain constants being equal, or |
| * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to |
| * detect if someone changes it. |
| * |
| * The implementation uses gcc's reluctance to create a negative array, but gcc |
| * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to |
| * inline functions). Luckily, in 4.3 they added the "error" function |
| * attribute just for this type of case. Thus, we use a negative sized array |
| * (should always create an error on gcc versions older than 4.4) and then call |
| * an undefined function with the error attribute (should always create an |
| * error on gcc 4.3 and later). If for some reason, neither creates a |
| * compile-time error, we'll still have a link-time error, which is harder to |
| * track down. |
| */ |
| #ifndef __OPTIMIZE__ |
| #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) |
| #else |
| #define BUILD_BUG_ON(condition) \ |
| BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) |
| #endif |
| |
| /** |
| * BUILD_BUG - break compile if used. |
| * |
| * If you have some code that you expect the compiler to eliminate at |
| * build time, you should use BUILD_BUG to detect if it is |
| * unexpectedly used. |
| */ |
| #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) |
| |
| #endif /* __CHECKER__ */ |
| |
| #endif /* _LINUX_BUILD_BUG_H */ |