Re: perf build error with gcc 10 on arm and aarch64

[Mike Leach]

Hi Leo,

This is caused by GCC 10 new default to -fno-common. Temporarily
adding this to perf build reproduces issue with other compilers,
including x86 build of perf with cs-etm.
As such - your fix is good to resolve this issue.

Tested by / Reviewed by Mike Leach <mike.leach@xxxxxxxxxx>

On Tue, 5 May 2020 at 05:11, Leo Yan <leo.yan@xxxxxxxxxx> wrote:
>
> Hi Thomas,
>
> [ + Mathieu/Mike/Suzuki ]
>
> On Mon, May 04, 2020 at 10:22:27PM +0300, Thomas Backlund wrote:
> > This is building perf from kernel-5.6.10 on armv7hl and aarch64:
> >
> > Compiler is gcc 10.1.0-RC
> >
> >
> >   LD       perf-in.o
> > ld: arch/perf-in.o: in function `.LANCHOR0':
> > /home/iurt/rpmbuild/BUILD/kernel-arm/linux-5.6/tools/perf/util/include/../../util/cs-etm.h:118:
> > multiple definition of `traceid_list'; util/perf-in.o:/home/iurt/rpmbuild/BUILD/kernel-arm/linux-5.6/tools/perf/util/cs-etm.h:118:
> > first defined here
> > make[3]: *** [/home/iurt/rpmbuild/BUILD/kernel-arm/linux-5.6/tools/build/Makefile.build:145:
> > perf-in.o] Error 1
> >
> >   LD       perf-in.o
> > ld: arch/perf-in.o:/home/iurt/rpmbuild/BUILD/kernel-aarch64/linux-5.6/tools/perf/util/include/../../util/cs-etm.h:118:
> > multiple definition of `traceid_list'; util/perf-in.o:/home/iurt/rpmbuild/BUILD/kernel-aarch64/linux-5.6/tools/perf/util/cs-etm.h:118:
> > first defined here
> > make[3]: *** [/home/iurt/rpmbuild/BUILD/kernel-aarch64/linux-5.6/tools/build/Makefile.build:145:
> > perf-in.o] Error 1
> > make[2]: *** [Makefile.perf:616: perf-in.o] Error 2
> > make[1]: *** [Makefile.perf:225: sub-make] Error 2
> > make: *** [Makefile:70: all] Error 2
> >
> >
> > The same build succeeds with gcc 9.3.0
>
> Thanks for reporting the issue.
>
> Could you help confirm if below change can resolve this issue?
>
> Thanks,
> Leo
>
> ---8<---
>
> Subject: [PATCH] perf cs-etm: Move defined of traceid_list
>
> The variable 'traceid_list' is defined in the header file cs-etm.h,
> if multiple C files include cs-etm.h the compiler might complaint for
> multiple definition of 'traceid_list'.
>
> To fix multiple definition error, move the definition of 'traceid_list'
> into cs-etm.c.
>
> Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
> ---
>  tools/perf/util/cs-etm.c | 3 +++
>  tools/perf/util/cs-etm.h | 3 ---
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 62d2f9b9ce1b..381d9708e9bd 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -94,6 +94,9 @@ struct cs_etm_queue {
>         struct cs_etm_traceid_queue **traceid_queues;
>  };
>
> +/* RB tree for quick conversion between traceID and metadata pointers */
> +static struct intlist *traceid_list;
> +
>  static int cs_etm__update_queues(struct cs_etm_auxtrace *etm);
>  static int cs_etm__process_queues(struct cs_etm_auxtrace *etm);
>  static int cs_etm__process_timeless_queues(struct cs_etm_auxtrace *etm,
> diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
> index 650ecc2a6349..4ad925d6d799 100644
> --- a/tools/perf/util/cs-etm.h
> +++ b/tools/perf/util/cs-etm.h
> @@ -114,9 +114,6 @@ enum cs_etm_isa {
>         CS_ETM_ISA_T32,
>  };
>
> -/* RB tree for quick conversion between traceID and metadata pointers */
> -struct intlist *traceid_list;
> -
>  struct cs_etm_queue;
>
>  struct cs_etm_packet {
> --
> 2.17.1



-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK