Re: [PATCH 02/21] perf pmu: Add const to pmu_events_map.

[Andrew Kilroy]

On 08/10/2021 12:01, John Garry wrote:
> On 07/10/2021 17:56, Ian Rogers wrote:
> > The pmu_events_map is generated at compile time and used for lookup. For
> > testing purposes we need to swap the map being used. Having the
> > pmu_events_map be non-const is misleading as it may be an out argument.
> > Make it const and update uses so they work on const too.
> >
> > Signed-off-by: Ian Rogers<irogers@xxxxxxxxxx>
>
> Reviewed-by: John Garry <john.garry@xxxxxxxxxx>

Got a compile error for this on arm64 when basing these patches on 
acme/perf/core (be8ecc57f180415e8a7c1cc5620c5236be2a7e56):

$ make DEBUG=1 O=output
...<snipped>...
arch/arm64/util/pmu.c:6:24: error: conflicting types for 
‘pmu_events_map__find’
 struct pmu_events_map *pmu_events_map__find(void)
                        ^~~~~~~~~~~~~~~~~~~~
In file included from arch/arm64/util/pmu.c:4:0:
arch/arm64/util/../../../util/pmu.h:126:30: note: previous declaration 
of ‘pmu_events_map__find’ was here
 const struct pmu_events_map *pmu_events_map__find(void);
                              ^~~~~~~~~~~~~~~~~~~~
arch/arm64/util/pmu.c: In function ‘pmu_events_map__find’:
arch/arm64/util/pmu.c:21:10: error: return discards ‘const’ qualifier 
from pointer target type [-Werror=discarded-qualifiers]
   return perf_pmu__find_map(pmu);
          ^~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
/home/andkil01/linux/tools/build/Makefile.build:96: recipe for target 
'/home/andkil01/linux/tools/perf/output/arch/arm64/util/pmu.o' failed
make[6]: *** 
[/home/andkil01/linux/tools/perf/output/arch/arm64/util/pmu.o] Error 1
/home/andkil01/linux/tools/build/Makefile.build:139: recipe for target 
'util' failed
make[5]: *** [util] Error 2
/home/andkil01/linux/tools/build/Makefile.build:139: recipe for target 
'arm64' failed
make[4]: *** [arm64] Error 2
/home/andkil01/linux/tools/build/Makefile.build:139: recipe for target 
'arch' failed
make[3]: *** [arch] Error 2
make[3]: *** Waiting for unfinished jobs....


Andrew