bug#46495: 28.0.50; [native-comp] Build fails for 32bit --with-wide-int

[Eli Zaretskii <eliz@gnu.org>]

> From: Andrea Corallo <akrl@sdf.org>
> Cc: dmalcolm@redhat.com, andrewjmoreton@gmail.com, 46495@debbugs.gnu.org
> Date: Wed, 31 Mar 2021 08:47:37 +0000
> 
> > AFAIU, this means the libgccjit log file is only output with
> > comp-debug 3 and higher?
> 
> Correct, the docstring wasn't correct :/ aa159bf696 should update it to
> reflect the current situation.

Thanks.

> > Also, does comp-debug = 3 indeed cause the
> > reproducer to be written, or is that controlled independently by
> > comp-libgccjit-reproducer?
> 
> The reproducer is controlled independently by
> `comp-libgccjit-reproducer', the idea behind this is that we want to be
> able to produce reproducers independently from the debug settings (we
> might have a ligccjit bug that is related to one debug option).

Right, so comp-debug = 3 alone doesn't trigger the reproducer, right?

> My proposal would be like:
> 
> 0 none
> 1 debug symbols
> 2 debug symbols + pseudo C file
> 3 debug symbols + pseudo C file + GCC passes + libgccjit log file
> 
> I think the backtrace issue you are facing is clearly a gdb unwinder
> limitation on Windows that should be fixed in gdb.

It's more like a missing feature in GDB on platforms that don't use
ELF binary format.  I don't hold my breath to have the situation
improved, since this is so far a rare situation when debugging
programs: no one expects debugging code without debug symbols to be
easy.

> OTOH I understand we can't update gdb for all users that might want
> to help debugging an issue, but I don't like very much the idea to
> have comp-debug 1 as default on every system.  What about having 1
> as default only on Windows?  WDYT?

In general, I'd prefer these settings to be the same on all platforms,
although it isn't a strong feeling in this case.  But I'm curious why
you are so against doing that by default on other systems.  Can you
explain?

Anyway, I've compiled the relevant files with comp-debug = 1, and the
problems with backtraces are now completely gone.  So I think we can
more or less close this issue (modulo changing the meanings of
comp-debug and the decision regarding the default value).