cargo-gccrs VS mrustc

We have `cargo-gccrs` for this, so a cargo subcommand which intercepts arguments given to `rustc` and converts them into `gccrs` arguments :)

https://github.com/rust-GCC/cargo-gccrs/

it's still in a relatively early stage as we are focusing on the compiler. But the idea is for it to be a drop-in replacement for compilation and execution operations, so you'd have `cargo gccrs build`, `cargo gccrs run`, `cargo gccrs test`, etc

gccrs is the compiler (like rustc). You can use cargo with gccrs : https://github.com/Rust-GCC/cargo-gccrs

See https://github.com/Rust-GCC/cargo-gccrs. There will definetly some sort of cargo support in the end. Either by having a behave-like-rustc wrapper around gccrs or by adding support directly to cargo or a cargo fork.

Cargo support for gccrs is part of this project:

https://github.com/Rust-GCC/cargo-gccrs

Moreover, modules are less interesting to me in embedded development as is access to Rust's borrow checker for gaining certainty of small portions of larger projects, which are written in other languages.

- With the [cargo-gccrs](https://github.com/Rust-GCC/cargo-gccrs/) we want to integrate gccrs as seamless as possible into the Rust ecosystem. So yes.

No, you don't. Existential proof: mrustc ignores lifetimes. Just flat out simply ignores. It changes some corner-cases related to HRBT, yet rustc compiled by mrustc works (that's BTW mrustc exist: to bootsrap the rustc compiler).

Incidentally C++ is the only way to bootstrap rust without rust today.

https://github.com/thepowersgang/mrustc

Well, there is mrustc[0], a Rust compiler that doesn't include a borrow-checker, so it's possible to compile (at least some versions of) Rust without a borrow checker, though it might not result in the most optimized code.

AFAIK there are some optimization like the infamous `noalias` optimization (which took several tries to get turned on[1]) that uses information established during borrow checking.

I'm also not sure what the relation with NLL (non-lexical lifetimes) is, where I would assume you would need at least a primitive borrow-checker to establish some information that the backend might be interested in. Then again, mrustc compiles Rust versions that have NLL features without a borrow-checker, so it's again probably more on the optimization side than being essential.

[0]: https://github.com/thepowersgang/mrustc

[1]: https://stackoverflow.com/a/57259339

> Maybe another memory safe language, but Rust has severe bootstrapping issues which is a hard sell for distros that care about source to binary transparency.

It is possible to bootstrap rustc from just GCC relatively easily, although it's a little bit time consuming.

You can use mrustc to bootstrap Rust 1.54: https://github.com/thepowersgang/mrustc

And from then you can go through each version all the way to the current 1.72. (Each new Rust version officially needs the previous one to compile.)

Have you tried this route : https://github.com/thepowersgang/mrustc ?

Mrustc supports Rust 1.54.0 today

There are three. The official one, mrustc (no borrow checker, but can essentially compile the official rustc) and GCC (can't really compile anything substantial yet). Only rustc is production-ready though.

That probably depends on what you mean by problematic. Having an ever increasing chain of dependencies isn’t the most desirable situation so there has been some work to trim the bootstrap chain. In 2018, when the blogpost I linked above was written, mrustc was used to bootstrap rust 1.19.0; now mrustc can bootstrap rust 1.54.0 so the chain to recent versions is much shorter than if all those intervening versions back through 1.19.0 needed to be built. https://github.com/thepowersgang/mrustc