On Thu, Sep 26, 2024 at 06:11:17PM +0200, Miguel Ojeda wrote: > On Thu, Sep 26, 2024 at 5:56 PM Conor Dooley <conor@xxxxxxxxxx> 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? No. Things like clang + ld & gas. I don't care about out of tree modules ;) > > 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. Okay. Short term then is deny gcc + rust, longer term is allow it with the same caveats as the aforementioned mixed stuff. > 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. Cool, I'll check that out. > > 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. Yes, just for riscv. The logic in our Kconfig menu is currently something like select HAVE_RUST if RUSTC_SUPPORTS_RISCV so that would just become select HAVE_RUST if RUSTC_SUPPORTS_RISCV && CC_IS_CLANG > > > 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. Cool, sounds good.
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