arewefastyet VS rustc_codegen_gcc

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!

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