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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
bc6245e5 IA |
2 | #ifndef _LINUX_BUILD_BUG_H |
3 | #define _LINUX_BUILD_BUG_H | |
4 | ||
5 | #include <linux/compiler.h> | |
6 | ||
7 | #ifdef __CHECKER__ | |
bc6245e5 | 8 | #define BUILD_BUG_ON_ZERO(e) (0) |
bc6245e5 | 9 | #else /* __CHECKER__ */ |
bc6245e5 IA |
10 | /* |
11 | * Force a compilation error if condition is true, but also produce a | |
87889943 | 12 | * result (of value 0 and type int), so the expression can be used |
bc6245e5 IA |
13 | * e.g. in a structure initializer (or where-ever else comma expressions |
14 | * aren't permitted). | |
15 | */ | |
87889943 | 16 | #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); }))) |
527edbc1 MY |
17 | #endif /* __CHECKER__ */ |
18 | ||
19 | /* Force a compilation error if a constant expression is not a power of 2 */ | |
20 | #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \ | |
21 | BUILD_BUG_ON(((n) & ((n) - 1)) != 0) | |
22 | #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \ | |
23 | BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0)) | |
bc6245e5 IA |
24 | |
25 | /* | |
26 | * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the | |
27 | * expression but avoids the generation of any code, even if that expression | |
28 | * has side-effects. | |
29 | */ | |
30 | #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e)))) | |
31 | ||
32 | /** | |
33 | * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied | |
34 | * error message. | |
35 | * @condition: the condition which the compiler should know is false. | |
36 | * | |
37 | * See BUILD_BUG_ON for description. | |
38 | */ | |
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) | |
40 | ||
41 | /** | |
42 | * BUILD_BUG_ON - break compile if a condition is true. | |
43 | * @condition: the condition which the compiler should know is false. | |
44 | * | |
45 | * If you have some code which relies on certain constants being equal, or | |
46 | * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to | |
47 | * detect if someone changes it. | |
bc6245e5 | 48 | */ |
bc6245e5 IA |
49 | #define BUILD_BUG_ON(condition) \ |
50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) | |
bc6245e5 IA |
51 | |
52 | /** | |
53 | * BUILD_BUG - break compile if used. | |
54 | * | |
55 | * If you have some code that you expect the compiler to eliminate at | |
56 | * build time, you should use BUILD_BUG to detect if it is | |
57 | * unexpectedly used. | |
58 | */ | |
59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") | |
60 | ||
6bab69c6 RV |
61 | /** |
62 | * static_assert - check integer constant expression at build time | |
63 | * | |
64 | * static_assert() is a wrapper for the C11 _Static_assert, with a | |
65 | * little macro magic to make the message optional (defaulting to the | |
66 | * stringification of the tested expression). | |
67 | * | |
68 | * Contrary to BUILD_BUG_ON(), static_assert() can be used at global | |
69 | * scope, but requires the expression to be an integer constant | |
70 | * expression (i.e., it is not enough that __builtin_constant_p() is | |
71 | * true for expr). | |
72 | * | |
73 | * Also note that BUILD_BUG_ON() fails the build if the condition is | |
74 | * true, while static_assert() fails the build if the expression is | |
75 | * false. | |
76 | */ | |
77 | #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr) | |
78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg) | |
79 | ||
07a368b3 ML |
80 | |
81 | /* | |
82 | * Compile time check that field has an expected offset | |
83 | */ | |
84 | #define ASSERT_STRUCT_OFFSET(type, field, expected_offset) \ | |
85 | BUILD_BUG_ON_MSG(offsetof(type, field) != (expected_offset), \ | |
86 | "Offset of " #field " in " #type " has changed.") | |
87 | ||
88 | ||
bc6245e5 | 89 | #endif /* _LINUX_BUILD_BUG_H */ |