Hi Sasha,
First, the following commit:
commit b5bf1733d6a391c4e90ea8f8468d83023be74a2a
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Date: Wed Feb 8 17:01:46 2017 -0300
tools include: Add a __fallthrough statement
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@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: William Cohen <wcohen@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-qnpig0xfop4hwv6k4mv1wts5@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
That is required because there already some commits picked to 4.1 that
use __fallthrough without the declaration, namely:
ed83069083743b perf top: Use __fallthrough
9de93e56698fe2 tools string: Use __fallthrough in perf_atoll()
Next, the following commit is required to make perf build in
distributions with new Perl:
commit b581c01fff646b5075d65359c8667de9c667da9e
Author: Namhyung Kim <namhyung@xxxxxxxxxx>
Date: Tue Aug 2 11:43:17 2016 +0900
perf tools: Fix build failure on perl script context
On my Archlinux machine, perf faild to build like below:
CC scripts/perl/Perf-Trace-Util/Context.o
In file included from /usr/lib/perl5/core/perl/CORE/perl.h:3905:0,
from Context.xs:23:
/usr/lib/perl5/core/perl/CORE/inline.h: In function :
/usr/lib/perl5/core/perl/CORE/cop.h:612:13: warning: declaration of 'av'
shadows a previous local [-Werror-shadow]
AV *av =3D GvAV(PL_defgv);
^
/usr/lib/perl5/core/perl/CORE/inline.h:526:5: note: in expansion of
macro 'CX_POP_SAVEARRAY'
CX_POP_SAVEARRAY(cx);
^~~~~~~~~~~~~~~~
In file included from /usr/lib/perl5/core/perl/CORE/perl.h:5853:0,
from Context.xs:23:
/usr/lib/perl5/core/perl/CORE/inline.h:518:9: note:
shadowed declaration is here
AV *av;
^~
What I did to fix is adding '-Wno-shadow' as the error message said it's
the cause of the failure. Since it's from the perl (not perf) code
base, we don't have the control so I just wanted to ignore the warning
when compiling perl scripting code.
Committer note:
This also fixes the build on Fedora Rawhide.
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20160802024317.31725-1-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Thanks.