Rustc_codegen_GCC can now bootstrap rustc

#1

Post by bestouff » Fri, Apr 01, 2022, 7:50 AM UTC

Rustc_codegen_GCC can now bootstrap rustc
blog.antoyo.xyz

Re: Rustc_codegen_GCC can now bootstrap rustc

#2

Post by VWWHFSfQ » Fri, Apr 01, 2022, 1:09 PM UTC

This is all very exciting. I'm guessing we'll see some pretty major performance improvements for rust code in addition to all the new supported architectures

Re: Rustc_codegen_GCC can now bootstrap rustc

#3

Post by goombacloud » Fri, Apr 01, 2022, 1:36 PM UTC

It's really great to be able to skip compiling LLVM when bootstrapping a whole OS/toolchain from source and only Rust happens to pull LLVM in.

Besides the gcc work I'm actually also hoping for the rustc_codegen_cranelift work to land one day!

Re: Rustc_codegen_GCC can now bootstrap rustc

#4

Post by roblabla » Fri, Apr 01, 2022, 1:47 PM UTC

VWWHFSfQ wrote: post #2

This is all very exciting. I'm guessing we'll see some pretty major performance improvements for rust code in addition to all the new supported architectures

I don't see why the GCC codegen would end up with major performance improvements - my understanding is that GCC and LLVM are basically on par with performance, with some workloads being a tiny bit better in one or the other. Is that wrong?

Re: Rustc_codegen_GCC can now bootstrap rustc

#5

Post by Vogtinator » Fri, Apr 01, 2022, 1:53 PM UTC

goombacloud wrote: post #3

It's really great to be able to skip compiling LLVM when bootstrapping a whole OS/toolchain from source and only Rust happens to pull LLVM in. Besides the gcc work I'm actually also hoping for the rustc_codegen_cranelift work to land one day!

For proper bootstrapping I'm looking forward to gccrs (https://github.com/Rust-GCC/gccrs) alongside mrustc.

Re: Rustc_codegen_GCC can now bootstrap rustc

#6

Post by hardware2win » Fri, Apr 01, 2022, 1:54 PM UTC

goombacloud wrote: post #3

It's really great to be able to skip compiling LLVM when bootstrapping a whole OS/toolchain from source and only Rust happens to pull LLVM in. Besides the gcc work I'm actually also hoping for the rustc_codegen_cranelift work to land one day!

Compiling llvm is a nightmare

Re: Rustc_codegen_GCC can now bootstrap rustc

#7

Post by bumblebritches5 » Fri, Apr 01, 2022, 2:02 PM UTC

roblabla wrote: post #4

VWWHFSfQ wrote: post #2

This is all very exciting. I'm guessing we'll see some pretty major performance improvements for rust code in addition to all the new supported architectures

I don't see why the GCC codegen would end up with major performance improvements - my understanding is that GCC and LLVM are basically on par with performance, with some workloads being a tiny bit better in one or the other. Is that wrong?

No post body was provided.

Re: Rustc_codegen_GCC can now bootstrap rustc

#8

Post by wyldfire » Fri, Apr 01, 2022, 2:12 PM UTC

hardware2win wrote: post #6

goombacloud wrote: post #3

It's really great to be able to skip compiling LLVM when bootstrapping a whole OS/toolchain from source and only Rust happens to pull LLVM in. Besides the gcc work I'm actually also hoping for the rustc_codegen_cranelift work to land one day!

Compiling llvm is a nightmare

In terms of satisfying the dependencies, or the build time, or something else?

Re: Rustc_codegen_GCC can now bootstrap rustc

#9

Post by JonChesterfield » Fri, Apr 01, 2022, 2:20 PM UTC

wyldfire wrote: post #8

hardware2win wrote: post #6

Earlier quoted context omitted.

Compiling llvm is a nightmare

In terms of satisfying the dependencies, or the build time, or something else?

Dependencies are few and largely optional but build time is tedious

Re: Rustc_codegen_GCC can now bootstrap rustc

#10

Post by aseipp » Fri, Apr 01, 2022, 2:22 PM UTC

wyldfire wrote: post #8

hardware2win wrote: post #6

Earlier quoted context omitted.

Compiling llvm is a nightmare

In terms of satisfying the dependencies, or the build time, or something else?

Build time. If you only need one or two components (clang, clang-tools-extra) and trim down the number of target architectures, it's not so bad. But if you want most of the components and architectures enabled, and tested with a Release-with-asserts build...

The build parallelism scales pretty well though so if you want some white noise in the background, by all means. It's kind of nice for keeping your feet warm sometimes.