Re: [PATCH] meson: distinguish build and target host binaries

From: Patrick Steinhardt <ps@pks.im>
Date: Mar 4, 2025, 09:07 UTC
Message-ID: <Z8bC5LINEPmoarRy@pks.im>
In-Reply-To: <20250303150956.24a1815e@gmx.net>

On Mon, Mar 03, 2025 at 03:09:56PM +0100, Peter Seiderer wrote:

Show 12 quoted lines

> > this patch addresses the issue reported at [1], where it is impossible
> > to specify the shell, Python and Perl paths during cross-compilation
> > when using Meson.
> 
> I still believe that is is a 'misuse' of the cross-file (as stated already
> here [1]) the given programs in cross-file are to be meant to run while
> cross-compiling (at compile time) and not on the target (e.g. it would be
> impossible to find a program (as the name find_program indicates) at
> compile/configure where the target layout is yet unknown....
> 
> I believe the correct solution is an extra configure option for cross-compile
> and a sane default (or find_program) in case of native build...

I'm mostly going by Eli's assessment [1]:

On Tue, Feb 18, 2025 at 09:41:23AM -0500, Eli Schwartz wrote:

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> Overriding it via the cross file would be fine -- if your goal is to
> only ever find_program(..., native: false) in order to detect a path and
> embed it, then it doesn't matter whether cross files are for running
> cross tools on the build machine or for looking up cross tools to detect
> a path and embed it, since the two goals would never *come into
> conflict*. And that's what actually matters -- if you are concerned that
> cross files will be wrong as they specify the cross-compile environment
> not the install environment, then you shouldn't be using find_program()
> either, you should be exclusively using build options.

So this makes me assume that this usage is okay.

The reason why I prefer using a cross-file is that it makes it possible to specify the complete environment for a cross-compilation in a single file. This would include both the toolchain, but also target-specific options like the shell/Python/Perl path. In theory, this would make it possible to eventually start shipping machine files as part of the Git project that are completely sufficient to set up cross-compilation for e.g. Windows.

That being said, this is only my opinion and it's not set into stone. I just don't quite see the cross-file as abuse and think it has merit to do it that way. If there is another good argument why having a build option is preferable then I'm all ears and happy to revise my opinion.

Patrick

[1]: 24df8aa2-760f-4da3-88b0-ab97796373fd@gentoo.org