You would also need to comprehensively annotate the Linux C headers in order to provide the information that Rust expects (e.g. for each ptr instance whether it's a "raw" pointer, a shared/exclusive reference or a piece of "owned" data, whether it can be NULL etc. etc.). This might actually get accepted upstream though. Having the kernel-build itself depend on Rust could be far more problematic, given e.g. the variety of hardware that Linux must support.

I would think such a thing would be more like "compiling" rust to C. As in the C code would have no means to maintain most of the safety guarantees, rather they would be verified at compile time, and the produced C would be meant to be used unchanged. So as long as nobody ever edits the C manually, it would still presumably be safe.

That's what I really meant. Write it in Rust but then output C instead of ASM. The parent is right though. A component/driver would need to use the C headers from the Rust side.

Not only that, but Rust depends on LLVM.

Last time I looked at this comment it was flagged [dead]; I'm glad someone was able to remedy that as I was unable to upvote.

I think this is a good criticism, but might not be true forever and is certainly something to keep in mind.

As I said in the GP, Rust will not be upstreamed into the kernel- this is one of the reasons why.

If a comment is dead that you think is worthwhile, you can follow the permalink to it and vouch for it. I imagine that feature is gated behind some point threshold, but my guess is whatever that threshold is you're past it.

Oh, nice, thanks for that. :)

It doesn't have to, but yes, it currently pretty much requires LLVM.

The output of the translator would be right, but messy, and someone would have to go back and clean it up. Doing that work would almost certainly introduce bugs. How many, and whether it outweighs is the question.

There is a lot of work being done on a translator now [0]. However, the goal is to translate C to equivalent Rust and then allow developers to intervene to migrate to safe Rust.

[0]: https://c2rust.com

EDIT: Oops, read the parent comment backwards.

That's C to Rust, not Rust to C. (mrustc provides something like the latter, but it doesn't actually support full Rust.)