Re: [PATCH 1/1 next] tools build: Remove the libunwind feature tests from the ones detected when test-all.o builds

[Ian Rogers]

On Mon, Mar 17, 2025 at 10:06 AM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> Hello,
>
> On Mon, Mar 17, 2025 at 09:10:29AM -0700, Ian Rogers wrote:
> > On Wed, Dec 11, 2024 at 7:45 AM Arnaldo Carvalho de Melo
> > <acme@xxxxxxxxxx> wrote:
> > >
> > > We have a tools/build/feature/test-all.c that has the most common set of
> > > features that perf uses and are expected to have its development files
> > > available when building perf.
> > >
> > > When we made libwunwind opt-in we forgot to remove them from the list of
> > > features that are assumed to be available when test-all.c builds, remove
> > > them.
> > >
> > > Before this patch:
> > >
> > >   $ rm -rf /tmp/b ; mkdir /tmp/b ; make -C tools/perf O=/tmp/b feature-dump ; grep feature-libunwind-aarch64= /tmp/b/FEATURE-DUMP
> > >   feature-libunwind-aarch64=1
> > >   $
> > >
> > > Even tho this not being test built and those header files being
> > > available:
> > >
> > >   $ head -5 tools/build/feature/test-libunwind-aarch64.c
> > >   // SPDX-License-Identifier: GPL-2.0
> > >   #include <libunwind-aarch64.h>
> > >   #include <stdlib.h>
> > >
> > >   extern int UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
> > >   $
> > >
> > > After this patch:
> > >
> > >   $ grep feature-libunwind- /tmp/b/FEATURE-DUMP
> > >   $
> > >
> > > Now an audit on what is being enabled when test-all.c builds will be
> > > performed.
> > >
> > > Fixes: 176c9d1e6a06f2fa ("tools features: Don't check for libunwind devel files by default")
> > > Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> > > Cc: Ian Rogers <irogers@xxxxxxxxxx>
> > > Cc: James Clark <james.clark@xxxxxxxxxx>
> > > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > > Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> > > Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> > > Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> >
> > Sorry for the delay on this.
> >
> > Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
>
> Thanks for the review, but I think this part is used by other tools like
> BPF and tracing.  It'd be nice to get reviews from them.

Sgtm. The patch hasn't had attention for 3 months. A quick grep for
"unwind" and "UNW_" shows only use in perf and the feature tests.

Thanks,
Ian