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Subject[PATCH] utilize _Static_assert() for BUILD_BUG_ON() when the compiler supports it
This makes the resulting diagnostics quite a bit more useful.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

---
include/linux/bug.h | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

--- 3.7-rc3/include/linux/bug.h
+++ 3.7-rc3-static-assert/include/linux/bug.h
@@ -27,8 +27,15 @@ struct pt_regs;
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). */
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+#define BUILD_BUG_ON_ZERO(e) \
+ sizeof(struct { _Static_assert(!(e), "!(" #e ")"); })
+#define BUILD_BUG_ON_NULL(e) \
+ ((void *)sizeof(struct { _Static_assert(!(e), "!(" #e ")"); }))
+#else
#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
+#endif

/*
* BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
@@ -54,6 +61,15 @@ struct pt_regs;
*/
#ifndef __OPTIMIZE__
#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
+#elif __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
+#define __build_bug_on_failed(n) __build_bug_on_##n##_failed
+#define _BUILD_BUG_ON(n, condition) \
+ do { \
+ extern void __compiletime_error(#condition) \
+ __build_bug_on_failed(n)(void); \
+ if (condition) __build_bug_on_failed(n)(); \
+ } while(0)
+#define BUILD_BUG_ON(condition...) _BUILD_BUG_ON(__COUNTER__, ##condition)
#else
extern int __build_bug_on_failed;
#define BUILD_BUG_ON(condition) \




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