April 2024 Monthly report

Overview

Thanks again to Open Source Security, inc and Embecosm for their ongoing support for this project.

Project update

This month was dedicated to making final preparations for the GCC 14.1 release, to ensure that our frontend would be distributed as part of it and that the user experience would be as good as possible. This meant working on adding build system detection for our newly-required Rust dependency, as well as make sure you can compile and link with the Rust standard library if your system uses an older libc version.

Unfortunately, we did not manage to get a build system patch merged in time before the 14.1 branch was frozen. This patch was purely for the quality of life of GCC developers, as it errored out your Rust build early in case you did not have certain Rust dependencies, and we chose to hold off of upstreaming our patches until it was merged to cause the least friction possible. This means that the version of the Rust frontend that will be released in GCC 14.1 will not contain our latest development, namely around the parsing of format strings and the ability to use them.

If this is of interest, we will be working towards making official binary releases of gccrs available in major Linux distributions. We are focusing on Arch Linux, Debian/Ubuntu and Fedora at the moment.

The results of the GSoC selection were also announced - We will be mentoring three students this year, and we are thrilled to welcome them. In no particular order, they are: Kushal Pal, Jasmine Tang and Muhammad Mahad!

• Jasmine Tang (https://github.com/badumbatish/) will be working on adding support for inline assembly in gccrs. There are many differences between Rust’s inline assembly and GCC’s, so this project will be extremely involved and will affect the entire compiler pipeline. Give her website a read: https://badumbatish.github.io

• Muhammad Mahad (https://github.com/MahadMuhammad/) will continue his work on adding support for Rust’s error codes to gccrs. This summer, he will focus on adapting the rustc testsuite for us to run it with our compiler frontend, bridging the gap between the two implementations.

• Kushal Pal (https://github.com/braw-lee/) will be contributing to our borrow checker interface, namely with the goal of adding proper user-facing errors. This interface consists of a new IR, entirely dedicated to interacting with the polonius-engine borrow-check crate.

It was extremely difficult to restrict ourselves to three people, as the quality of proposals was really high this year. If we had more mentors, we would have chosen more students. In total, 7 students were accepted into the GCC organization for this year’s GSoC, meaning that gccrs managed to get 43% of all the selected candidates. We are now entering the community bonding period, where the mentors will get in touch with the mentees and start setting up weekly video calls. We will also start working on project design together, and will put together milestones with specific deadlines for each of the subjects.

Finally, our CI setup got bogged down for a couple of days due to an upgrade in github’s MacOS container image. A lot of PRs were stuck in review as a result, and will be merged in the coming days.

Community call

We will have our next monthly community call on the 13th of May at 9am UTC. You can subscribe to our calendar to see when the next one will be held. The call is open to everyone, even if you would just like to sit-in and listen. You can also subscribe to our mailing-list or join our Zulip chat to be notified of upcoming events.

• Jitsi link
• Calendar ID: 7060a0923ffebd3cb52b1afef35a28ff7b64f05962c9af84c23b1847f1f5f894@group.calendar.google.com
• Google calendar link
• iCal link

Call for contribution

• Issue 2030: Improve error message in operator expression

The goal of this issue is to improve the compiler’s output when reporting that an arithmetic operator was used on a type where it is not supported. In the example code, it is specifically about the “add-assign” operator being used on values of type &str, but the error reporting mechanism should be reported to all operators for all types.

You will have to look for the error message in the compiler sources and look at improving it. Take inspiration from rustc, as their output is very good :)

• Issue 2062: Missing feature gate negative_impls

In order to support this feature gate, you will need to to work on our feature gating visitor and add this specific gate. You will then need to check trait implementations, and report an error if one is used while the feature is not active. This will give you a good insight into our compiler’s AST pipeline and will make you work with our visitor framework.

Completed Activities

• Remove unnecessary SIDE_EFFECTS/READONLY macros PR2977
• Pin macos CI to version 13 PR2976
• Removed obsolete objects PR2968
• Resolve impl block type with name resolution 2.0 PR2952
• chore: Fix Remark CI PR2950
• Move ‘libformat_parser’ build into the GCC build directory, and into libgrust PR2947
• Merge upstream, 2024-03-09 PR2944
• libgrust: Vendor Rust dependencies PR2943
• Add an alternative solution on MacOS PR2941
• Remove redundant macro definition PR2925
• Borrowck tests and build PR2889

Contributors this month

• Mael Cravero (new contributor!)
• Kushal Pal
• Jasmine Tang
• Thomas Schwinge
• zhanghe
• Jakub Dupak

Overall Task Status

Test Cases

Bugs

Milestones Progress

Testing project

Planned Activities

• Create milestones for 15.1 release
• Create distribution packages for Linux distributions

Risks

Detailed changelog