[meta-freescale] [linux-fslc-imx][4.1-2.0.x-imx][PATCH] tools include: Add a __fallthrough statement

[Stefan Agner]

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

[ Upstream commit b5bf1733d6a391c4e90ea8f8468d83023be74a2a ]

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 at intel.com>
Cc: David Ahern <dsahern at gmail.com>
Cc: Jiri Olsa <jolsa at kernel.org>
Cc: Namhyung Kim <namhyung at kernel.org>
Cc: Wang Nan <wangnan0 at huawei.com>
Cc: William Cohen <wcohen at redhat.com>
Link: http://lkml.kernel.org/n/tip-qnpig0xfop4hwv6k4mv1wts5@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme at redhat.com>
---
This fixes build errors when building perf such as:
util/string.c: In function ‘perf_atoll’:                                                                                                    
util/string.c:25:4: error: ‘__fallthrough’ undeclared (first use in this
function)                                                          
    __fallthrough;                                                                                                                          
    ^~~~~~~~~~~~~   


 tools/include/linux/compiler.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h
index 88461f09cc86..8717c80f759c 100644
--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -37,4 +37,12 @@
 
 #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 */
-- 
2.14.1