rustc_codegen_cranelift VS arewefastyet

Windows is supported. See https://github.com/rust-lang/rustc_codegen_cranelift/issues/....

> When this happens, it seems like it'll be possible to get the LLVM bits out of the bootstrap process and lead to a fully self-hosted Rust.

What do you mean by "when this happens"? GP's point is that this has already happened: the Cranelift backend is feature-complete from the perspective of the language [0], except for inline assembly and unwinding on panic. It was merged into the upstream compiler in 2020 [1], and a compiler built with only the Cranelift backend is perfectly capable of building another compiler. LLVM hasn't been a necessary component of the Rust compiler for quite some time.

[0] https://github.com/bjorn3/rustc_codegen_cranelift

[1] https://github.com/rust-lang/rust/pull/77975

Note that the Cranelift codegen will eventually become standard for debug builds to speed them up.

Maybe one day we'll have rustc b3 backend like what they did with Cranelift

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.

For the instant reloading, that's in Sycamore, so you should speak to its devs, but as for the alternative compiler backend, it's not my project, but it uses Cranelift and works pretty well! See https://github.com/bjorn3/rustc_codegen_cranelift for details.

The more immediate goal of "distribute the cranelift backend as a rustup component" has been making good progress and seems like it might happen relatively soon https://github.com/bjorn3/rustc_codegen_cranelift/milestone/...

That page averages all the builds across different code bases. It doesn’t specify which version/tag of which code base, nor does it talk about the hardware.

https://arewefastyet.pages.dev/ - This page tracks compile times across some common crates over all supported compiler versions, with different hardware (2, 4, 8, 16 cores). This used to be https://arewefastyet.rs but the domain expired.

https://arewefastyet.rs/ see benchmark

You can check incremental compile times on http://arewefastyet.rs. Choose one compile mode (Debug OR Release, preferably Debug), one hardware config (4 cores let's say) and both profile modes (Clean, Incremental).

Compile times in rustc have been steadily improving with time, as shown here - https://arewefastyet.rs.

Every release doesn't make every workload faster, but over a long time horizon, the effect is clear. Rust 1.34 was released in April 2019 and since then many crates have become 33-50% faster to compile, depending on the hardware and the compiler mode (clean/incremental, check/debug/release).

Interestingly, the speedup mentioned in OP won't show up in these charts because that's a change on macOS and these benchmarks were recorded on Linux.

What is expected to be a gamechanger is the release of cranelift in 2021 or 2022. It's an alternate debug backend that promises much faster debug builds.

Yes plenty of effort goes into making Rust compilation faster, see https://arewefastyet.rs/, its FAQ, and some easy internet searches.

Thanks for your work on arewefastyet.rs, I was about to post a link to it haha

I implemented something similar. Deserialising a comma separated strings into a struct - example. Hope that helps!