1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_BUILD_BUG_H 3 #define _LINUX_BUILD_BUG_H 4 5 #include <linux/compiler.h> 6 7 #ifdef __CHECKER__ 8 #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) (0) 9 #define BUILD_BUG_ON_NOT_POWER_OF_2(n) (0) 10 #define BUILD_BUG_ON_ZERO(e) (0) 11 #define BUILD_BUG_ON_INVALID(e) (0) 12 #define BUILD_BUG_ON_MSG(cond, msg) (0) 13 #define BUILD_BUG_ON(condition) (0) 14 #define BUILD_BUG() (0) 15 #else /* __CHECKER__ */ 16 17 /* Force a compilation error if a constant expression is not a power of 2 */ 18 #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \ 19 BUILD_BUG_ON(((n) & ((n) - 1)) != 0) 20 #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \ 21 BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0)) 22 23 /* 24 * Force a compilation error if condition is true, but also produce a 25 * result (of value 0 and type size_t), so the expression can be used 26 * e.g. in a structure initializer (or where-ever else comma expressions 27 * aren't permitted). 28 */ 29 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:(-!!(e)); })) 30 31 /* 32 * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the 33 * expression but avoids the generation of any code, even if that expression 34 * has side-effects. 35 */ 36 #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e)))) 37 38 /** 39 * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied 40 * error message. 41 * @condition: the condition which the compiler should know is false. 42 * 43 * See BUILD_BUG_ON for description. 44 */ 45 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) 46 47 /** 48 * BUILD_BUG_ON - break compile if a condition is true. 49 * @condition: the condition which the compiler should know is false. 50 * 51 * If you have some code which relies on certain constants being equal, or 52 * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to 53 * detect if someone changes it. 54 */ 55 #define BUILD_BUG_ON(condition) \ 56 BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) 57 58 /** 59 * BUILD_BUG - break compile if used. 60 * 61 * If you have some code that you expect the compiler to eliminate at 62 * build time, you should use BUILD_BUG to detect if it is 63 * unexpectedly used. 64 */ 65 #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") 66 67 #endif /* __CHECKER__ */ 68 69 #endif /* _LINUX_BUILD_BUG_H */ 70