Re: [PATCH 3/3] perf jevents: Suppress circular dependency warnings

[Namhyung Kim <namhyung@kernel.org>]

On Mon, Oct 20, 2025 at 05:08:28PM +0100, James Clark wrote:
> When doing an in source build, $(OUTPUT) is empty so the rule has the
> same input and output file. Suppress the warning by only adding the rule
> when doing an out of source build. The same condition already exists for
> the clean rule for json files.
> 
> This fixes the following warnings:
> 
>   make[3]: Circular pmu-events/arch/nds32/mapfile.csv <- pmu-events/arch/nds32/mapfile.csv dependency dropped.
>   make[3]: Circular pmu-events/arch/powerpc/mapfile.csv <- pmu-events/arch/powerpc/mapfile.csv dependency dropped.
>   ...

I noticed this too and confirm it's fixed by this change.

Tested-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung

> 
> Signed-off-by: James Clark <james.clark@linaro.org>
> ---
>  tools/perf/pmu-events/Build | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/pmu-events/Build b/tools/perf/pmu-events/Build
> index c5e2d5f13766..a46ab7b612df 100644
> --- a/tools/perf/pmu-events/Build
> +++ b/tools/perf/pmu-events/Build
> @@ -29,10 +29,12 @@ $(PMU_EVENTS_C): $(EMPTY_PMU_EVENTS_C)
>  	$(call rule_mkdir)
>  	$(Q)$(call echo-cmd,gen)cp $< $@
>  else
> -# Copy checked-in json for generation.
> +# Copy checked-in json to OUTPUT for generation if it's an out of source build
> +ifneq ($(OUTPUT),)
>  $(OUTPUT)pmu-events/arch/%: pmu-events/arch/%
>  	$(call rule_mkdir)
>  	$(Q)$(call echo-cmd,gen)cp $< $@
> +endif
>  
>  $(LEGACY_CACHE_JSON): $(LEGACY_CACHE_PY)
>  	$(call rule_mkdir)
> 
> -- 
> 2.34.1
>