Re: [RFC, patch] Detect lack of 32-bit devel environment on x86_64-linux targets

[Richard Biener <richard dot guenther at gmail dot com>]

On Wed, Feb 12, 2014 at 11:57 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Wed, Feb 12, 2014 at 11:52:47AM +0100, Richard Biener wrote:
>> On Tue, Feb 11, 2014 at 5:17 PM, Jakub Jelinek <jakub@redhat.com> wrote:
>> > On Fri, Jan 31, 2014 at 03:49:40PM +0100, Richard Biener wrote:
>> >> On Fri, Jan 31, 2014 at 3:45 PM, FX <fxcoudert@gmail.com> wrote:
>> >> >> I've just seen that an explicit --enable-multilib is a way to do that.
>> >> >
>> >> > Yes, I was writing that as a reply when I received your email. (Also, it's written in the configure error message.)
>> >>
>> >> Yeah - you know, that message is quite long and somehow I didn't read it
>> >> carefully.  I suspect that will happen to others, too, so we'll get some
>> >> extra complaints from that ;)
>> >>
>> >> >> Btw, doing the configure check exactly after all-stage1-gcc should be
>> >> >> an early enough and a serialization point, no?  There you can do the
>> >> >> check even for when cross-compiling.
>> >> >
>> >> > Well, you've already built a whole stage, so it's not so early, is it?
>> >>
>> >> Well, building the stage1 compiler is probably the fastest thing nowadays
>> >> (it didn't yet build the target libraries for stage1 with the stage1,
>> >> unoptimized
>> >> and checking-enabled compiler - which is where it would fail in the odd
>> >> way which is what you want to improve).
>> >>
>> >> As I said, you can't "properly" check it at the point you are checking.
>> >> Which is why I complain - you're not checking this properly!
>> >>
>> >> Anyway, I've fixed the "bug" on our side with --enable-multilib.
>> >
>> > Just hit the same thing, while I have (in mock) 32-bit devel libc installed,
>> > I don't have 32-bit libgcc_s installed (what for, it will be built by gcc).
>> >
>> > Please revert it, or at least improve it (e.g. by trying to build
>> > with -static-libgcc at least).
>>
>> I wouldn't have static 32bit libgcc installed either.
>
> So perhaps turn that into a check if preprocessing of #include <features.h>
> works with -m32 (and never complain when building --with-sysroot*)?
> I mean, if features.h doesn't preprocess successfully (because of missing
> /usr/include/gnu/stubs-32.h), then as long as the compiler is going to
> include the same headers and not some sysroot, multilib building would fail
> in that case too.

That sounds good to me.  Though it still wouldn't work with a
non-multilib built host compiler (maybe detect that and just warn
but not abort for that case?).

Richard.

>         Jakub