Re: Cross compilation status

[Efraim Flashner <efraim@flashner.co.il>]

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On Sun, Sep 10, 2023 at 11:14:29AM +0200, Mathieu Othacehe wrote:
> 
> Hello,
> 
> In order for Guix to become an alternative to tools such as Yocto and
> Buildroot, having most or all our packages cross-compiling is a
> prerequisite.
> 
> Here is a status of cross-compilation in Guix. For cross-compilation to
> work, the build-system needs to support cross-compilation.
> 
> The following build-systems explicitly refuse cross-compiling packages:
> 
<snip>
> 
> ocaml: 61
> haskell: 812
> maven: 2
> chicken: 12
> node: 57
> emacs: 1370
> dune: 289
> android-ndk: 12
> waf: 21
> julia: 300
> pyproject: 433
> r: 2441
> cargo: 3535
> ruby: 597
> rebar: 22
> scons: 15
> rakudo: 22
> agda: 6
> ant: 559
> python: 2488
> Cross-compilation KO: 13054
> --8<---------------cut here---------------end--------------->8---
> 
> Over the 28076 packages in Guix, 15065 are part of build-systems with
> cross-compilation support and 13054 are part of build-systems without
> cross-compilation support.
> 
> Overall 46.5% of our packages will refuse to cross-compile with errors
> such as:
> 
> --8<---------------cut here---------------start------------->8---
> mathieu@meije ~$ guix build --target=aarch64-linux-gnu librsvg
> guix build: error: gnu/packages/gnome.scm:3500:2: librsvg@2.54.5: build system `cargo' does not support cross builds
> --8<---------------cut here---------------end--------------->8---
> 
> I'd like to help converge towards the situation where all build-systems
> support cross-compilation.
> 
> I have CC'ed members of the python, java, ruby, rust, r, haskell and
> emacs teams. Any plans adding cross-compilation support to your
> build-system, barriers to overcome?

I suspect librsvg is especially a problem since it is almost always
pulled in with any sort of image building. I haven't looked at it
closely yet, but I believe that in order to support cross-compilation
support in rust we'll need to enable more targets, which will increase
the build time for the final rust and the final output size. Considering
that nothing built with rust links to it, I'm not convinced this is a
problem.

We will likely see people confused that we have a rust with
cross-compiling abilities but with windows- and mac-specific
(pre-compiled) libraries removed, so it wouldn't be able to
cross-compile to those (or some other) platforms without changes.


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Efraim Flashner   <efraim@flashner.co.il>   רנשלפ םירפא
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