On Wed, 2020-03-11 at 14:17 +0000, Jonathan Wakely wrote:
> On Mon, 9 Mar 2020 at 21:56, Paul Smith wrote:
> > The tricky bit is that although both the host and target are always
> > x86_64/i686 GNU/Linux systems, I need the generated compiler to run on
> > much older systems than the one I build it on.
>
> I suggest using containers for this. Once you've got a working
> Dockerfile it makes life much easier in my experience.
>
> The podman and buildah utilities are great alternatives to docker itself.
>
> By building in a container using something like "FROM centos:6" you
> know you're using those packages, not trying to convince GCC to use a
> cobbled-together sysroot based on old RPMs.
That's a good idea, certainly for building the compiler: it would save me
having to build the initial compiler ("step 1" in Joseph's email): I can
skip that step and just build the target compiler in a container.
Unfortunately currently I target RHEL/CentOS 6.5 and there's no official
docker image for that, but that's not a major problem.
However I don't think, at least for now, I can switch to having developers
build in a docker container. Getting that integrated with all the
tooling/IDE environments everyone uses, etc. will be a lot of change.
Since I want to use a much newer version of GCC than was provided in these
older releases, a docker image won't save me having to build the compiler
anyway; it would only change the way the compiler is distributed and used
(inside a docker image/container vs. stand-alone with a sysroot).
Luckily for me our product only relies on a handful of system libraries and
I have a simple script that will extract them from RPMs via cpio. It's
actually quite easy and robust to create the sysroot and the entire thing
is only 16M.
