/* SPDX-License-Identifier: GPL-2.0 */#ifndef _LINUX_BUILD_BUG_H#define _LINUX_BUILD_BUG_H #include <linux/compiler.h> /* * Force a compilation error if condition is true, but also produce a * 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, ...) \	__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)	\	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)) /* * 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. * @cond: the condition which the compiler should know is false. * @msg: build-time error message * * 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. */#define BUILD_BUG_ON(condition) \	BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) /** * 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 * @expr: expression to be checked * * 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. */#ifndef static_assert#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)#define __static_assert(expr, msg, ...) _Static_assert(expr, msg)#endif // static_assert  /* * 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 */