Re: [PATCH 3/5] tools lib subcmd: Add dependency test to install_headers

[Ian Rogers]

On Mon, Dec 12, 2022 at 12:57 PM Nicolas Schier <nicolas@xxxxxxxxx> wrote:
>
> On Thu, Dec 01, 2022 at 08:57:41PM -0800 Ian Rogers wrote:
> > Compute the headers to be installed from their source headers and make
> > each have its own build target to install it. Using dependencies
> > avoids headers being reinstalled and getting a new timestamp which
> > then causes files that depend on the header to be rebuilt.
> >
> > Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> > ---
> >  tools/lib/subcmd/Makefile | 23 +++++++++++++----------
> >  1 file changed, 13 insertions(+), 10 deletions(-)
> >
> > diff --git a/tools/lib/subcmd/Makefile b/tools/lib/subcmd/Makefile
> > index 9a316d8b89df..b87213263a5e 100644
> > --- a/tools/lib/subcmd/Makefile
> > +++ b/tools/lib/subcmd/Makefile
> > @@ -89,10 +89,10 @@ define do_install_mkdir
> >  endef
> >
> >  define do_install
> > -     if [ ! -d '$(DESTDIR_SQ)$2' ]; then             \
> > -             $(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2'; \
> > +     if [ ! -d '$2' ]; then             \
> > +             $(INSTALL) -d -m 755 '$2'; \
> >       fi;                                             \
> > -     $(INSTALL) $1 $(if $3,-m $3,) '$(DESTDIR_SQ)$2'
> > +     $(INSTALL) $1 $(if $3,-m $3,) '$2'
>
> What about using '$(INSTALL) -D ...' instead of the if-mkdir-block above?
> (E.g. as in tools/debugging/Makefile.)
>
> Kind regards,
> Nicolas

Thanks Nicolas, the reason was to keep the code consistent. That's not
to say this is the best approach. For example, here is the same thing
for tools/lib/api:
https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/tree/tools/lib/api/Makefile?h=perf/core&id=f43368371888694a2eceaaad8f5e9775c092009a#n84

If you'd like to improve this in all the versions and send patches I'd
be happy to take a look.

Thanks,
Ian

> >  endef
> >
> >  install_lib: $(LIBFILE)
> > @@ -100,13 +100,16 @@ install_lib: $(LIBFILE)
> >               $(call do_install_mkdir,$(libdir_SQ)); \
> >               cp -fpR $(LIBFILE) $(DESTDIR)$(libdir_SQ)
> >
> > -install_headers:
> > -     $(call QUIET_INSTALL, libsubcmd_headers) \
> > -             $(call do_install,exec-cmd.h,$(prefix)/include/subcmd,644); \
> > -             $(call do_install,help.h,$(prefix)/include/subcmd,644); \
> > -             $(call do_install,pager.h,$(prefix)/include/subcmd,644); \
> > -             $(call do_install,parse-options.h,$(prefix)/include/subcmd,644); \
> > -             $(call do_install,run-command.h,$(prefix)/include/subcmd,644);
> > +HDRS := exec-cmd.h help.h pager.h parse-options.h run-command.h
> > +INSTALL_HDRS_PFX := $(DESTDIR)$(prefix)/include/subcmd
> > +INSTALL_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(HDRS))
> > +
> > +$(INSTALL_HDRS): $(INSTALL_HDRS_PFX)/%.h: %.h
> > +     $(call QUIET_INSTALL, $@) \
> > +             $(call do_install,$<,$(INSTALL_HDRS_PFX)/,644)
> > +
> > +install_headers: $(INSTALL_HDRS)
> > +     $(call QUIET_INSTALL, libsubcmd_headers)
> >
> >  install: install_lib install_headers
> >
> > --
> > 2.39.0.rc0.267.gcb52ba06e7-goog
>
> --
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