On Thu, Sep 26, 2024 at 5:56 PM Conor Dooley conor@kernel.org wrote:
Mixed builds are allowed on the c side, since we can figure out what the
I am not sure what you mean by allowed on the C side. For out-of-tree modules you mean?
versions of each tool are. If there's a way to detect the version of libclang in use by the rust side, then I would be okay with mixed gcc + rustc builds.
If you mean the libclang used by bindgen, yes, we have such a check (warning) in scripts/rust_is_available.sh. We can also have it as a Kconfig symbol if needed.
Regarding rustc's LLVM version, I wanted to have a similar check in scripts/rust_is_available.sh (also a warning), but it would have been quite noisy, and if LTO is not enabled it should generally be OK. So we are adding instead a Kconfig symbol for that, which will be used for a couple things. Gary has a WIP patch for this one.
Yes, I would rather this was not applied at all. My plan was to send a patch making HAVE_RUST depend on CC_IS_CLANG, but just ain't got around to it yet, partly cos I was kinda hoping to mention this to you guys at LPC last week, but I never got the chance to talk to any rust people (or go to any rust talks either!).
To be clear, that `depends on` would need to be only for RISC-V, i.e. other architectures are "OK" with those. It is really, really experimental, as we have always warned, but some people is using it successfully, apparently.
Sure, I can add a comment there.
Thanks!
In sorta related news, is there a plan for config "options" that will allow us to detect gcc-rs or the gcc rust backend?
gccrs is way too early to even think about that. rustc_codegen_gcc, yeah, if needed, we can add a symbol for that when we start supporting the backend.
Cheers, Miguel