rustc_codegen_gcc VS polonius

Alternatively, there's another initiative called codegen_gcc which is about using GCC as a backend for the rustc compiler. It's (much) more advanced in Rust support, but I am not sure how easy it would be to use a modified libgccjit from there.

In addition to what others have said about platform support, Rust is also on its way to gaining more platform support through rustc_codegen_gcc, the GCC codegen backend for rustc, as an alternative to the LLVM backend. That means many of the platforms GCC supports will suddenly become available with Rust.

Yeah, rustc_codegen_gcc is a GCC backend for rustc, and its making a lot of good regular progress.

gcc-rs is one of two projects for bringing Rust to gcc. gcc-rs is the more ambitious of the two, with an entirely new frontend. There is also rustc_codegen_gcc (https://github.com/rust-lang/rustc_codegen_gcc) that keeps the rustc frontend, and only swaps out LLVM for GCC at the codegen stage.

Fixing unwinding in release mode is still ungoing. I could use some help here, so anyone with some understanding of unwinding, landing pads or GCC, please come on this issue to discuss this.

Additionally, there is gcc codegen for rustc (https://github.com/rust-lang/rustc_codegen_gcc), which is not a compiler per se, but an alternative code generator, with more architectures supported and other nice things. It's also coming along, but there's still a lot of work to do there too. There's also Cranelift codegen (https://github.com/bjorn3/rustc_codegen_cranelift), which is designed to make debug builds faster, but this is not as exciting/useful as the other 2.

Good idea. I added the tag "help wanted" to the issue.

Also, there are indeed ABI issues, e.g. for 128-bit integers and NaN.

I'm excited about both the backend & the frontend.

There is also a project for rustc to use GCC instead of LLVM for codegen.

https://github.com/rust-lang/rustc_codegen_gcc

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.