rustc_codegen_gcc VS polonius

It's true that if this project succeeds, that would be an outcome, but it's probably worth noting that you'd really only have to add support for the GCC backend to do that, and not reimplement the frontend as well (parsing, type checking, lifetime checking, etc.). There's an unrelated project working to do that: https://github.com/antoyo/rustc_codegen_gcc that would likely yield those same benefits for less effort.

platform support (may improve soon)

Here's the gcc backend for rustc here https://github.com/antoyo/rustc_codegen_gcc Since this just swaps the optimizer/codegen module and reuses all the other stuff from rustc it needs less work and can already compile many valid rust programs.

I'd like to use the rustc_codegen_gcc backend to compile some Rust programs, but I'm confused about how to install and use the patched libgccjit dependency. I've downloaded the fork provided but don't know where to go from there.

I was being a little sloppy and mixing together "actual embedded hardware" with "extensions for applications written in other languages" in my head. I think your point about LLVM is still accurate, though I hear peeps about different projects working on GCC support from time to time.

This doesn't have anything to do with using GCC to compile rust, but instead using rustc to compile Rust using the GCC backend. You can do that today by using the linked project, rustc_codegen_gcc, which is intended to be integrated into rustc at some point in the (hopefully near) future.

Rather than mrustc you should probably look at rustc_codegen_gcc which uses gcc as a backend to rustc (WIP) or GCC Rust which tries to implement a rust frontend for gcc (also WIP). I think rustc_codegen_gcc looks the most promising at the moment

Libgccjit AOT Codegen for Rustc\ (2 comments)

Correctness prover which uses lifetimes (Polonius).

And, well, polonius (Rust borrow checker magic) I believe is built on datalog-ish concepts: https://github.com/rust-lang/polonius

There is also polonius (https://github.com/rust-lang/polonius) which should replace the borrow checker but does not receive a lot of development resources.

This is eventually going to be a feature-complete compiler, targeting a specific rustc version. I believe the plan is to use polonius [1], presumably as an "optional" feature so they can build a stage 1 without it, use that to build polonius, then build the final compiler with it included.

[1] https://github.com/rust-lang/polonius

E.g. there you may just stop using current borrow-checker and switch to Polonius.

The borrow checker is too dumb (https://github.com/rust-lang/polonius) fixes a lot of this.

It looks like an official borrow checker implementation called Polonius uses it as a dependency, so it makes sense: https://github.com/rust-lang/polonius/blob/981785c101b68ff54...

If you click around a little, you end up on a blog post with this tidbit:

> This project got put together rather suddenly, in response to some work the Rust folks are doing[1] on their new and improved borrow checker.

I don't think I could tell you more than "Frank wrote it to help rust folks who were previously doing work with differential-dataflow directly."

1. https://github.com/rust-lang/polonius/pull/36#issuecomment-3...

Good news is that there's also works going on to relax the restrictions, like polonius. But it seems that it still have a long way to go before it can land in stable Rust...

GCC-rs isn't intended for bootstrapping, it is intended to be an actual fully featured Rust compiler in the future, mrustc is a Rust compiler intended for bootstrapping though. GCC-rs is still very early targeting an older version of the reference compiler without things like a borrow checker, but that's not going to be the case forever. The GCC-rs folks have expressed interest in re-using the borrow checker library used by the reference compiler called polonius enabling them to relatively easily add borrow checking.