Re: Building gcc 4.9.2 on AIX 7.1

[Jonathan Wakely <jwakely.gcc@gmail.com>]

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On Tue, 13 Jun 2023, 13:36 Randy Galbraith via Gcc-help, <
gcc-help@gcc.gnu.org> wrote:

> On Mon, Jun 12, 2023 at 6:50 PM David Edelsohn <dje.gcc@gmail.com> wrote:
>
> > >>> Randy Galbraith wrote:
> >
> > > We have a need to match gcc version on Red Hat GNU/Linux 7. I am
> looking
> > > forward to newer GCC once Red Hat is upgraded. However, that will
> likely
> > > break our build. We elevate every warning in gcc to error status that
> > stops
> > > the building. Thus we need to plan for that. At the moment I just need
> to
> > > support the AIX 7.2 upgrade. Ironically had our port to GNU/Linux been
> > > completed this would not be an issue. Cheers, -Randy
> >
> > Red Hat provides newer releases of GCC through the GCC Toolset
> > package, but that may be limited to RHEL 8.  RHEL 7 is quite old.
> >
> > Does your AIX 7.2 system have all of the latest Technology Levels
> > (TLs) and Service Packs (SPs) installed? There have been many
> > assembler and linker fixes.
> >
> > If you still have GCC 4.9.2 from the AIX 7.1 system, you should be
> > able to continue to use it.  You can rebuild the "fixed" headers
> > without rebuilding the entire compiler.  I don't believe that anyone
> > has tried bootstrapping GCC with XLC in a very long time.
> >
> > GCC builds and works with AIX Assembler and AIX Linker.  Until
> > recently, GNU Assembler and GNU Linker were out of date on AIX 7.x and
> > produced corrupted object files. The latest GNU Binutils functions.
> > It might be better to ensure that the AIX tools are used (AIX as, ld,
> > ar).
> >
> > GCC 4.9 is very old. I don't have any intuition about why GCC (without
> > any optimization) would generate unusual code for ferror().  Again, I
> > would ensure that you are not using the GNU Assembler for your
> > bootstrap.
> >
> > Thanks, David
> >
>
> I am trying to land a new GCC compiler to address the break related to
> fixed headers. If these could be rebuilt without having to land a new
> compiler I would be most interested in the steps to do that! Any advice on
> where to start with that? Cheers, -Randy
>


See https://gcc.gnu.org/onlinedocs/gcc/Fixed-Headers.html which describes
the mkheaders script. That is installed as part of the GCC installation,
and running it will update the fixed headers.