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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Vinson reported build breakage with gcc 4.4 due to strict-aliasing.
CC util/annotate.o
cc1: warnings being treated as errors
util/annotate.c: In function ‘disasm__purge’:
linux-next/tools/include/linux/compiler.h:66: error: dereferencing
pointer ‘res.41’ does break strict-aliasing rules
The reason is READ_ONCE/WRITE_ONCE code we took from kernel sources. They
intentionaly break aliasing rules. While this is ok for kernel because it's
built with -fno-strict-aliasing, it breaks perf which is build with
-Wstrict-aliasing=3.
Using extra __may_alias__ type to allow aliasing in this case.
Reported-and-tested-by: Vinson Lee <vlee@twopensource.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Martin Liska <mliska@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rabin Vincent <rabin@rab.in>
Cc: linux-next@vger.kernel.org
Link: http://lkml.kernel.org/r/20151013085214.GB2705@krava.brq.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
