mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 18:09:57 +00:00
3a176b9460
This reverts commit14dc3983b5. Macro Elver had sent a fix proper fix earlier, and also pointed out corner cases: "I guess what you propose is simpler, but might still have corner cases where we still get warnings. In particular, if some file (for whatever reason) does not include build_bug.h and uses a raw _Static_assert(), then we still get warnings. E.g. I see 1 user of raw _Static_assert() (drivers/gpu/drm/amd/amdgpu/amdgv_sriovmsg.h )." I believe the raw use of _Static_assert() should be allowed, so this should be fixed in genksyms. Even after commit14dc3983b5("kbuild: avoid static_assert for genksyms"), I confirmed the following test code emits the warning. ---------------->8---------------- #include <linux/export.h> _Static_assert((1 ?: 0), ""); void foo(void) { } EXPORT_SYMBOL(foo); ---------------->8---------------- WARNING: modpost: EXPORT symbol "foo" [vmlinux] version generation failed, symbol will not be versioned. Now that commit 869b91992bce ("genksyms: Ignore module scoped _Static_assert()") fixed this issue properly, the workaround should be reverted. Link: https://lkml.org/lkml/2020/12/10/845 Link: https://lkml.kernel.org/r/20201219183911.181442-1-masahiroy@kernel.org Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Cc: Marco Elver <elver@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
80 lines
2.8 KiB
C
80 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_BUILD_BUG_H
|
|
#define _LINUX_BUILD_BUG_H
|
|
|
|
#include <linux/compiler.h>
|
|
|
|
#ifdef __CHECKER__
|
|
#define BUILD_BUG_ON_ZERO(e) (0)
|
|
#else /* __CHECKER__ */
|
|
/*
|
|
* 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).
|
|
*/
|
|
#define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
|
|
#endif /* __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))
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
#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
|
|
*
|
|
* 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 /* _LINUX_BUILD_BUG_H */
|