From 84b8bf6d5d2a52fb40124c881de162b094ff5cc1 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 24 Jan 2016 23:27:48 +0900 Subject: bug.h: move BUILD_BUG_* defines to include/linux/bug.h BUILD_BUG_* macros have been defined in several headers. It would be nice to collect them in include/linux/bug.h like Linux. This commit is cherry-picking useful macros from include/linux/bug.h of Linux 4.4. I did not import BUILD_BUG_ON_MSG() because it would not work if it is used with include/common.h in U-Boot. I'd like to postpone it until the root cause (the "error()" macro in include/common.h causes the name conflict with "__attribute__((error()))") is fixed. Signed-off-by: Masahiro Yamada Reviewed-by: Tom Rini --- include/common.h | 3 --- include/linux/bug.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+), 3 deletions(-) create mode 100644 include/linux/bug.h (limited to 'include') diff --git a/include/common.h b/include/common.h index 7bed0cc0d1..1563d649f0 100644 --- a/include/common.h +++ b/include/common.h @@ -146,9 +146,6 @@ void __assert_fail(const char *assertion, const char *file, unsigned line, #define BUG_ON(condition) do { if (unlikely((condition)!=0)) BUG(); } while(0) #endif /* BUG */ -/* Force a compilation error if condition is true */ -#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) - typedef void (interrupt_handler_t)(void *); #include /* boot information for Linux kernel */ diff --git a/include/linux/bug.h b/include/linux/bug.h new file mode 100644 index 0000000000..920e3796c3 --- /dev/null +++ b/include/linux/bug.h @@ -0,0 +1,55 @@ +#ifndef _LINUX_BUG_H +#define _LINUX_BUG_H + +#include + +#ifdef __CHECKER__ +#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(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) == 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 - 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. + */ +#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) + +#endif /* __CHECKER__ */ + +#endif /* _LINUX_BUG_H */ -- cgit