rustc_codegen_gcc: Progress Report #7

What is rustc_codegen_gcc?

rustc_codegen_gcc is a GCC codegen for rustc, meaning that it can be loaded by the existing rustc frontend, but benefits from GCC by having more architectures supported and having access to GCC’s optimizations.

GCC patches status

Again this month, a lot of progress happened here! My third, my fourth and my fifth patches were merged.

My patch for global initializer was dropped in favor of this patch.

State of rustc_codegen_gcc

This month, I continued working on supporting integer types not supported on some platforms. The PR is still not merged yet because some new UI tests now fail. This indeed surfaced an issue with bitcasts in my libgccjit patch that I’ll have to fix. I also need to make the tests of libcore pass when 128-bit integers are not supported.

To make sure this continue working in the future, I added CI with a version of libgccjit with 128-bit integers disabled. As you can see here, most of them pass:

test result: FAILED. 1359 passed; 22 failed; 0 ignored; 0 measured; 0 filtered out; finished in 13.35s

(To be noted: the tests of libcore still pass for the normal case of using native integers. They only fail (for now) when using non-native integers.)

Also, a few other things were done last month:

Here are the results of running the UI tests in the CI:

test result: FAILED. 4446 passed; 77 failed; 55 ignored; 0 measured; 0 filtered out; finished in 603.56s

For the next month, I’ll continue working on non-native integers and hopefully merge this PR. I also want to do some cleanup of the code in this PR and also of the code it generates.

How to contribute


If you want to help on the project itself, please do the following:

  1. Run the tests locally.

  2. Choose a test that fails.

  3. Investigate why it fails.

  4. Fix the problem.

Even if you can’t fix the problem, your investigation could help, so if you enjoy staring at assembly code, have fun!

Crates and rustc

If you would like to contribute on adding support for Rust on currently unsupported platforms, you can help by adding the support for those platforms in some crates like libc and object and also in the rust compiler itself.

Test this project

Otherwise, you can test this project on new platforms and also compare the assembly with LLVM to see if some optimization is missing.

Good first issue

Finally, another good way to help is to look at good first issues. Those are issues that should be easier to start with.

Thanks for your support!

I wanted to personally thank all the people that sponsor this project: your support is very much appreciated.

A special thanks to the following sponsors:

  • igrr

  • saethlin

  • embark-studios

  • Traverse-Research

  • Shnatsel

A big thank you to bjorn3 for his help and reviews. And a big thank you to lqd and GuillaumeGomez for answering my questions about rustc’s internals. Another big thank you to Commeownist for his contributions.

Also, a big thank you to the rest of my sponsors:

  • kpp

  • repi

  • nevi-me

  • Alovchin91

  • oleid

  • acshi

  • joshtriplett

  • djc

  • TimNN

  • sdroege

  • pcn

  • steven-joruk

  • davidlattimore

  • Nehliin

  • colelawrence

  • zmanian

  • alexkirsz

  • regiontog

  • berkus

  • wezm

  • belzael

  • vincentdephily

  • mexus

  • jam1garner

  • Shoeboxam

  • evanrichter

  • stuhood

  • yerke

  • bes

  • raymanfx

  • seanpianka

  • srijs

  • 0xdeafbeef

  • kkysen

  • messense

  • riking

  • rafaelcaricio

  • Lemmih

  • memoryruins

  • pthariensflame

  • senden9

  • Hofer-Julian

  • robjtede

  • Jonas Platte

  • spike grobstein

  • Oliver Marshall

  • Sam Harrington

  • Cass

  • Jonas

  • Jeff Muizelaar

  • Robin Moussu

  • Chris Butler

  • Dakota Brink

  • sierrafiveseven

  • Joseph Garvin

  • Paul Ellenbogen

  • icewind

  • Sebastian Zivota

  • Oskar Nehlin

  • Nicolas Barbier

  • Daniel

  • Justin Ossevoort

  • sstadick

  • luizirber

  • kiyoshigawa

  • robinmoussu

and a few others who preferred to stay anonymous.