Re: fix libcc1 dependencies in toplevel Makefile

[Olivier Hainque <hainque@adacore.com>]

Hi Alex,

(Back from a few days away)

> On 27 Jun 2017, at 21:50, Alexandre Oliva <aoliva@redhat.com> wrote:
> 
>> I don't quite understand this: we're using the same prerequisite as target
>> libraries, e.g. all-target-libstdc++-v3 or all-target-libbacktrace
> 
> Not quite.  Target libraries have deps on e.g. target-libgcc, look below
> the following comments in Makefile.in:
> 
> # Dependencies for target modules on other target modules are
> # described by lang_env_dependencies; the defaults apply to anything
> # not mentioned there.
> 
> plus, maybe-configure*-target-libgcc depend on maybe-all*-gcc (see above
> those comments).  The precise deps vary per bootstrap level, or
> non-bootstrap.
> 
> But after the proposed patch there are no such deps for libcc1 in the
> bootstrap case, so we might very well attempt to build libcc1 in
> parallel with gcc.  We shouldn't do that.
> 
> But then, it all works out because we only build all-host after
> bootstrap is complete; all-stage* doesn't depend on libcc1 at all.

I think I see.

[...]

> So, would you like to give the automatic figuring out of
> non-bootstrap-on-bootstrap deps in dependencies, and guard them between
> @if gcc-no-bootstrap and @endif (then both configure- and all- libcc1
> deps would be adjusted this way)?  (I'm not saying it should be trivial
> to do or anything like that; I'm not all that familiar with it and I'd
> have to figure it out myself if I were to do it, but I think that would
> be better than adding yet another means of introducing dependencies,
> while leaving another risky dep in place)


I'm willing to study this more and see what can be done
to improve things further. There are still a few details I don't
quite grasp so it'll just take a bit of time.

Thanks a lot for the additional set of extensive comments!

With Kind Regards,

Olivier