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Subject: Re: [PATCH 3/3] tools/build: Display logical OR of a feature flavors
From:   Roberto Sassu <roberto.sassu@huaweicloud.com>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     peterz@infradead.org, mingo@redhat.com, mark.rutland@arm.com,
        alexander.shishkin@linux.intel.com, jolsa@kernel.org,
        namhyung@kernel.org, quentin@isovalent.com,
        linux-perf-users@vger.kernel.org, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Roberto Sassu <roberto.sassu@huawei.com>
Date:   Thu, 18 Aug 2022 15:25:36 +0200
In-Reply-To: <Yv46EW6KbUe9zjur@kernel.org>
References: <20220818120957.319995-1-roberto.sassu@huaweicloud.com>
         <20220818120957.319995-3-roberto.sassu@huaweicloud.com>
         <Yv46EW6KbUe9zjur@kernel.org>
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On Thu, 2022-08-18 at 10:09 -0300, Arnaldo Carvalho de Melo wrote:
> Em Thu, Aug 18, 2022 at 02:09:57PM +0200, 
> roberto.sassu@huaweicloud.com escreveu:
> > From: Roberto Sassu <roberto.sassu@huawei.com>
> > 
> > Sometimes, features are simply different flavors of another
> > feature, to
> > properly detect the exact dependencies needed by different Linux
> > distributions.
> > 
> > For example, libbfd has three flavors: libbfd if the distro does
> > not
> > require any additional dependency; libbfd-liberty if it requires
> > libiberty;
> > libbfd-liberty-z if it requires libiberty and libz.
> > 
> > It might not be clear to the user whether a feature has been
> > successfully
> > detected or not, given that some of its flavors will be set to OFF,
> > others
> > to ON.
> > 
> > Instead, display only the feature main flavor if not in verbose
> > mode
> > (VF != 1), and set it to ON if at least one of its flavors has been
> > successfully detected (logical OR), OFF otherwise. Omit the other
> > flavors.
> > 
> > Accomplish that by declaring a FEATURE_GROUP_MEMBERS-<feature main
> > flavor>
> > variable, with the list of the other flavors as variable value. For
> > now, do
> > it just for libbfd.
> > 
> > In verbose mode, of if no group is defined for a feature, show the
> > feature
> > detection result as before.
> 
> Looks cool, tested and added this to the commit log message here in
> my
> local branch, that will go public after further tests for the other
> csets in it:
> 
> Committer testing:
> 
> Collecting the output from:
> 
>   $ make -C tools/bpf/bpftool/ clean
>   $ make -C tools/bpf/bpftool/ |& grep "Auto-detecting system
> features" -A10
> 
>   $ diff -u before after
>   --- before    2022-08-18 10:06:40.422086966 -0300
>   +++ after     2022-08-18 10:07:59.202138282 -0300
>   @@ -1,6 +1,4 @@
>    Auto-detecting system features:
>    ...                                  libbfd: [ on  ]
>   -...                          libbfd-liberty: [ on  ]
>   -...                        libbfd-liberty-z: [ on  ]
>    ...                                  libcap: [ on  ]
>    ...                         clang-bpf-co-re: [ on  ]
>   $
> 
> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> Thanks for working on this!

Thanks for testing and for adapting/pushing the other patches!

Roberto