[PATCH 3.16 358/366] tools include: Add a __fallthrough statement

Ben Hutchings
2018-11-11T20:31:27Z

From: Arnaldo Carvalho de Melo <acme@redhat.com>

commit b5bf1733d6a391c4e90ea8f8468d83023be74a2a upstream.

For cases where implicit fall through case labels are intended,
to let us inform that to gcc >= 7:

CC /tmp/build/perf/util/string.o
util/string.c: In function 'perf_atoll':
util/string.c:22:7: error: this statement may fall through [-Werror=implicit-fallthrough=]
if (*p)
^
util/string.c:24:3: note: here
case '\0':
^~~~

So we introduce:

#define __fallthrough __attribute__ ((fallthrough))

And use it in such cases.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: William Cohen <wcohen@redhat.com>
Link: http://lkml.kernel.org/n/tip-qnpig0xfop4hwv6k4mv1wts5@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
tools/include/linux/compiler.h | 9 +++++++++
1 file changed, 9 insertions(+)

--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -37,4 +37,13 @@

#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))

+
+#ifndef __fallthrough
+# if defined(__GNUC__) && __GNUC__ >= 7
+# define __fallthrough __attribute__ ((fallthrough))
+# else
+# define __fallthrough
+# endif
+#endif
+
#endif /* _TOOLS_LINUX_COMPILER_H */