The patch titled
Subject: kernel.h: hide __is_constexpr() from sparse
has been added to the -mm tree. Its filename is
kernelh-hide-__is_constexpr-from-sparse.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kernelh-hide-__is_constexpr-from-sparse.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kernelh-hide-__is_constexpr-from-sparse.patch
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------------------------------------------------------
From: Johannes Berg <johannes.berg@xxxxxxxxx>
Subject: kernel.h: hide __is_constexpr() from sparse
__is_constexpr() is a work of art, understandable only to the most
respected wizards of C. Even sparse doesn't seem to belong to that group
and warns that there's an "expression using sizeof(void)".
Just hide the definition from sparse and pretend it's always true.
Link: http://lkml.kernel.org/r/20181109093534.15121-2-johannes@xxxxxxxxxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/kernel.h | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/include/linux/kernel.h~kernelh-hide-__is_constexpr-from-sparse
+++ a/include/linux/kernel.h
@@ -844,6 +844,7 @@ static inline void ftrace_dump(enum ftra
#define __typecheck(x, y) \
(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
+#ifndef __CHECKER__
/*
* This returns a constant expression while determining if an argument is
* a constant expression, most importantly without evaluating the argument.
@@ -851,6 +852,13 @@ static inline void ftrace_dump(enum ftra
*/
#define __is_constexpr(x) \
(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
+#else
+/*
+ * We don't really care about the check when running sparse and the
+ * above expression causes a warning due to sizeof(void).
+ */
+#define __is_constexpr(x) 1
+#endif
#define __no_side_effects(x, y) \
(__is_constexpr(x) && __is_constexpr(y))
_
Patches currently in -mm which might be from johannes.berg@xxxxxxxxx are
compiler-gcc-hide-compiler_has_generic_builtin_overflow-from-sparse.patch
kernelh-hide-__is_constexpr-from-sparse.patch
