Re: [PATCH v2] x86: Remove libopcodes dependency

["H.J. Lu" <hjl.tools@gmail.com>]

On Tue, Nov 29, 2022 at 10:58 PM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 30.11.2022 01:06, H.J. Lu wrote:
> > On Tue, Nov 29, 2022 at 11:38 AM H.J. Lu <hjl.tools@gmail.com> wrote:
> >>
> >> On Tue, Nov 29, 2022 at 1:22 AM Jan Beulich <jbeulich@suse.com> wrote:
> >>>
> >>> On 29.11.2022 00:49, H.J. Lu wrote:
> >>>> On Thu, Nov 24, 2022 at 2:19 AM Jan Beulich <jbeulich@suse.com> wrote:
> >>>>> On 22.11.2022 19:19, H.J. Lu wrote:
> >>>>>> --- a/gas/Makefile.am
> >>>>>> +++ b/gas/Makefile.am
> >>>>>> @@ -446,6 +446,12 @@ development.exp: $(BFDDIR)/development.sh
> >>>>>>       $(EGREP) "(development|experimental)=" $(BFDDIR)/development.sh  \
> >>>>>>         | $(AWK) -F= '{ print "set " $$1 " " $$2 }' > $@
> >>>>>>
> >>>>>> +$(srcdir)/../opcodes/i386-init.h $(srcdir)/../opcodes/i386-tbl.h: \
> >>>>>> +     @MAINT@ $(srcdir)/../opcodes/i386-opc.tbl \
> >>>>>> +     $(srcdir)/../opcodes/i386-reg.tbl \
> >>>>>> +     $(srcdir)/../opcodes/i386-opc.h
> >>>>>> +     cd ../opcodes; make gen-i386-tbl
> >>>>>
> >>>>> I've made a patch to gas/Makefile.am as you have requested in reply to
> >>>>> my series. I will want to put that through some more testing, so I will
> >>>>> submit a v3 of that only a little later (and of course only unless you
> >>>>> submit a v2 of your patch earlier that I would also end up being okay
> >>>>> with). In the course of doing so I noticed a few more issues with your
> >>>>> change:
> >>>>>
> >>>>> For one I don't think you can put @MAINT@ on a continued line, as the
> >>>>> line continuation might then be hidden when @MAINT@ expands to #. The
> >>>>> list of dependencies wants expressing via a variable, which would then
> >>>>> be used immediately after @MAINT@ without any line continuation
> >>>>> following.
> >>>>
> >>>> Fixed.
> >>>
> >>> No, the same problem is still there. You either need to use a very long
> >>> line, or you need to introduce a variable holding the list of prereqs,
> >>> like I've done in my series.
> >>
> >> I got
> >>
> >> $(srcdir)/../opcodes/i386-init.h $(srcdir)/../opcodes/i386-tbl.h:
> >> $(srcdir)/../opcodes/i386-opc.tbl \
> >>         $(srcdir)/../opcodes/i386-reg.tbl \
> >>         $(srcdir)/../opcodes/i386-opc.h \
> >>         $(srcdir)/../opcodes/i386-gen.c
> >>         $(MAKE) -C ../opcodes gen-i386-tbl
> >>
> >> and
> >>
> >> $(srcdir)/../opcodes/i386-init.h $(srcdir)/../opcodes/i386-tbl.h: #
> >> $(srcdir)/../opcodes/i386-opc.tbl \
> >>         $(srcdir)/../opcodes/i386-reg.tbl \
> >>         $(srcdir)/../opcodes/i386-opc.h \
> >>         $(srcdir)/../opcodes/i386-gen.c
> >>         $(MAKE) -C ../opcodes gen-i386-tbl
> >>
> >> I didn't run into any problems.
> >>
> >>>>> And then your rule / dependency won't be enough on a "maintainer-clean"
> >>>>> tree, i.e. when the generated headers aren't there at all, and when
> >>>>> config/.deps/tc-i386.Po is still empty. In that case nothing would
> >>>>> trigger their generation; an explicit dependency of config/tc-i386.o on
> >>>>> these headers needs adding here.
> >>>>
> >>>> Fixed.
> >>>>
> >>>>> Finally you're missing a dependency of the generated headers on
> >>>>> i386-gen.c.
> >>>>
> >>>> They have a dependency on i386-gen which depends on i386-gen.c.
> >>>
> >>> In opcodes/, yes, but talk was about the rule in gas/. Yet despite
> >>> your comment above I see that you've added the missing dependency.
> >>>
> >>>> Here is the v2 patch.
> >>>
> >>> As said in reply to v1 - my objection to this particular use of make
> >>> recursion remains.
> >>
> >> The gen-i386-tbl rule doesn't touch any files used by libopcodes.
> >
> > There are
> >
> > bfd/Makefile.in:   ($(am__cd) $$subdir && $(MAKE) $(AM_MAKEFLAGS)
> > $$local_target) \
> > binutils/Makefile.in:   ($(am__cd) $$subdir && $(MAKE) $(AM_MAKEFLAGS)
> > $$local_target) \
> > gas/Makefile.in:   ($(am__cd) $$subdir && $(MAKE) $(AM_MAKEFLAGS)
> > $$local_target) \
>
> I'm glad you spotted this yourself - I was just about to point out
> that my concern isn't only a theoretical one, because of the
> generated makefiles we use. You don't draw any conclusion though:
> Are you willing to accept my approach, specifically reworked to
> account for an extra request of yours? Or are you meaning to make
> another attempt yourself, avoiding the undue make recursion?
>

Calling $(MAKE) in Makefile is very normal in binutils-gdb.
I don't see anything wrong with my approach.  I prefer my
approach.

-- 
H.J.