On Wed, Jul 14, 2021 at 2:48 PM Tamar Christina via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi,
>
> Ever since this commit
>
> commit c9114f2804b91690e030383de15a24e0b738e856
> Author: Bernd Edlinger <bernd.edlin...@hotmail.de>
> Date: Fri May 28 06:27:27 2021 +0200
>
> Various tools have been having trouble with cross compilation resulting in
>
> make[2]: *** No rule to make target
> '../build-x86_64-build_pc-linux-gnu/libcpp/libcpp.a', needed by
> 'build/genmatch'.
>
> (took a while to track down). I don't understand this part of the build
> system well enough to know how to fix this.
> It looks like `libcpp.a` has special handling for cross compilers which now
> seems to be broken.
>
> I can't reproduce it with our normal cross compiler scripts. Which handles
> the stages on its own, but e.g.
> https://github.com/crosstool-ng/crosstool-ng does reproduce the failure.
>
> Any ideas what's going on?
There should be a dependence of all-gcc to all-build-libcpp, Makefile.def has
dependencies = { module=all-gcc; on=all-build-libcpp; };
so how come build-libcpp is not built when gcc/ starts?
> Kind Regards,
> Tamar
>
> > -----Original Message-----
> > From: Gcc-patches <gcc-patches-boun...@gcc.gnu.org> On Behalf Of
> > Michael Matz
> > Sent: Friday, May 28, 2021 4:33 PM
> > To: Bernd Edlinger <bernd.edlin...@hotmail.de>
> > Cc: gcc-patches@gcc.gnu.org; Richard Biener <rguent...@suse.de>
> > Subject: Re: [PATCH] Generate gimple-match.c and generic-match.c earlier
> >
> > Hello,
> >
> > On Fri, 28 May 2021, Bernd Edlinger wrote:
> >
> > > >> I was wondering, why gimple-match.c and generic-match.c are not
> > > >> built early but always last, which slows down parallel makes
> > > >> significantly.
> > > >>
> > > >> The reason seems to be that generated_files does not mention
> > > >> gimple-match.c and generic-match.c.
> > > >>
> > > >> This comment in Makefile.in says it all:
> > > >>
> > > >> $(ALL_HOST_OBJS) : | $(generated_files)
> > > >>
> > > >> So this patch adds gimple-match.c generic-match.c to generated_files.
> > > >>
> > > >>
> > > >> Tested on x86_64-pc-linux-gnu.
> > > >> Is it OK for trunk?
> > > >
> > > > This should help for what I was complaining about in
> > > > https://gcc.gnu.org/pipermail/gcc/2021-May/235963.html . I build
> > > > with
> > > > -j24 and it was stalling on compiling gimple-match.c for me.
> > > > Looks like insn-attrtab.c is missed too; I saw genattrtab was running
> > > > last
> > too.
> > > >
> > >
> > > Yeah, probably insn-automata.c as well, sometimes it is picked up
> > > early sometimes not. maybe $(simple_generated_c) should be added to
> > > generated_files, but insn-attrtab.c is yet another exception.
> >
> > You can't put files in there that are sometimes slow to generate (which
> > insn-
> > {attrtab,automata}.c are on some targets), as _everything_ then waits for
> > them to be created first.
> >
> > Ideally there would be a way for gnumake to mark some targets as "ugh-
> > slow" and back-propagate this to all dependencies so that those are put in
> > front of the work queue in a parallel make. Alas, something like that never
> > came into existence :-/ (When order-only deps were introduced I got
> > excited, but then came to realize that that wasn't what was really needed
> > for
> > this case, a "weak" version of it would be required at least, or better yet
> > a
> > specific facility to impose a cost with a target)
> >
> >
> > Ciao,
> > Michael.
> >
> > >
> > >
> > > Bernd.
> > >
> > > > Thanks,
> > > > Andrew
> > > >
> > > >>
> > > >>
> > > >> Thanks
> > > >> Bernd.
> > > >>
> > > >>
> > > >> 2021-05-28 Bernd Edlinger <bernd.edlin...@hotmail.de>
> > > >>
> > > >> * Makefile.in (generated_files): Add gimple-match.c and
> > > >> generic-match.c
> > >
