i386 packages for Ubuntu 24.04 (not possible to use this package repo for llvm20 if some Ubuntu i386 packages are installed)

[aescolar]

To be able to do or use multiarch builds (32bit x86 builds in x86 64bit hosts, to support 32bit userspace programs) we need the i386 builds of these packages.
These seem present for Debian but not for Ubuntu in this package repository ( apt.llvm.org ).

When one has an Ubuntu installation, and installs i386 packages from the Ubuntu distro, these are likely to depend on some i386 version of some of these libraries (i.e. libllvm20).
APT requires the version of the same package across all architectures installed in a multi-arch environment to be identical.

In particular we see that with an Ubuntu 24.04 installation with the libsdl2-dev:i386 package installed, it is not possible to run https://apt.llvm.org/llvm.sh
As it tries to pull libllvm20:amd64 (1:20.1.8~++20250804090239+87f0227cb601-1~exp1~20250804210352.139)
But only this 64bit version is available from this package repository.
While the only i386 available version, the one from the Ubuntu distro repo, is libllvm20 (1:20.1.2-0ubuntu1~24.04.2).
As these 2 packages versions are different, apt rejects to continue due to a version mismatch.

If this repository would also provide the matching i386 builds of these packages, both the i386 and amd64 variants could be installed in sync from it.

Related to zephyrproject-rtos/docker-image#269

Thanks in advance

Sidenote: I understand the packaging and platform:linux labels are applicable, but I can't add them myself.

[sylvestre]

sorry, i386 has been decommissioned for years on ubuntu

[aescolar]

Thanks for looking into this @sylvestre.

sorry, i386 has been decommissioned for years on ubuntu

When you say this, you mean this repository (apt.llvm.org) has not provided any packages for i386 for years? (if so, that is what I'm requested would be reconsidered as an option to fix this issue).

Ubuntu itself does not provide i386 kernel builds anymore, but it very much supports and provides i386 packages on a x86-64bit kernel to support 32bit userspace programs and development.
See for example: https://launchpad.net/ubuntu/noble/i386/libllvm20

Note that the issue here is not just that this repo does not provide i386 packages, but that the provided amd64 version of the packages conflict with the one provided by Ubuntu if one installs i386 packages from the Ubuntu distro repo, and therefore the corresponding packages from this repo cannot be installed.

[sylvestre]

I was talking about Ubuntu itself. See:
https://documentation.ubuntu.com/project/how-ubuntu-is-made/concepts/supported-architectures/
i386 is a partial-port of Ubuntu, which is supported as a multi-arch supplementary architecture. There is no kernel, no installers, and no bootloaders for i386, therefore it cannot be booted as a pure i386 installation. You have to crossbuild i386 or build in a i386 chroot on a amd64 host.

if you want to discuss more about it: sylvestre@debian.org