August 2024 Monthly report

Overview

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

Project update

This month saw really good progress in terms of the number of merged PRs, issues completed, and testcases added. All three Google Summer of Code projects got completed, which required extensive reviewing. Our three students passed the final evaluation brillantly, and are all interested in continuing to contribute to the compiler in their free time. We are very happy to have them join the team, and are looking forward to their future work. We have offered to help mentor them in the future, as well as to help with any compiler-related studies they might have. As a reminder, anyone interested in contributing to the project will be able to receive similar help and mentoring.

In fact, we are currently working with another student outside of GSoC to put together a testsuite and testing program which will help us assert that gccrs produces code with correct semantics (as a reminder, correct means “with rustc’s semantics”). It is important for gccrs to only accept the correct subset of code, but it is also necessary that the assembly we produce has the same meaning and the same runtime characteristics as any other Rust program. This ties into our pursuit of producing a “correct” compiler, which we’ll talk about more in a future blogpost in cooperation with the Rust project.

In terms of technical contributions, we have closed the Unhandled attributes milestone, which covered the handling of all attributes required for compiling core 1.49. We have made good progress on the Lang items milestone, with the only remaining step being to switch our existing code generation of lang item paths to these new paths we introduced. This will help all of our early code generation pipeline, namely surrounding built-in macros and the desugaring of certain constructs like for loops. Once this is done, we will fix the issues surrounding iterators and indexing, which currently prevent for loops from being completely implemented. We have gained a few new contributors this summer, and we hope that this trend continues. We hope they continue to contribute to the project, and will spend some time this week to try and help with the codebase when necessary. For a look at the work we plan on doing this year, check out the engineering document we established a few months ago.

Finally, we would like to be more public about gccrs’s progress. In some recent comments surrounding the Rust-for-Linux project, we have noted that some internauts believe that the work on the compiler has slowed down, despite our regular upstreaming and progress reports. We think this might be due to a lack of activity on social media and forums such as Reddit or HackerNews, and will start posting our monthly updates there again. We will also be coming out with a few blogposts in the coming weeks, namely around the progress achieved by our GSoC students and how it will impact users.

Community call

We will have our next monthly community call on the 16th of September 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 3001: Generic arguments are not disambiguated on error propagation expressions

Our error propagation expressions (expressions which use the question mark operator, of the form <expr>?) are currently forgotten in many of our AST visitors. As a result, there are unexpected cases when it comes to various parts of the compiler pipeline handling them. In that particular case, the function call’s generic arguments are not disambiguated - the compiler does not know if it needs to be handling a generic type, or a const generic value. You will need to add handling to our name resolution pass for these error propagation expressions. It would be helpful to look at the current generic disambiguation to start figuring out where it is called from, and where you need to call it.

Completed Activities

• gccrs: emit error code for E0758 PR3145
• Add glibcxx_assertion check PR3138
• Fix feature gate visitor PR3136
• attributes: Start handling prelude_import properly PR3135
• Fix the disorder struct and class in inline asm PR3133
• Attempted to access a nonexistent field [`E0609`] PR3131
• Better move errors PR3130
• Fixed testcase PR3128
• Add check for path patterns. PR3125
• rust: avoid clobbering LIBS PR3121
• Add running cicd 32bit PR3119
• Add error message for E0532 PR3118
• Fix 32-bits builds PR3114
• Better subset errors PR3113
• Improve compressed point bit manipulation PR3112
• Add check for union patterns PR3110
• Inline asm resolve expr PR3109
• Eager expansion for include* #1805 #1865 PR3107
• New test directories for mbe macros and builtins PR3105
• Inline asm hir pipeline PR3103
• Remove dependency on nightly Rust PR3101
• Fixed bitwise operation in `extract<sub>stmt</sub>` PR3100
• Fix the parser’s operand and flags storage PR3098
• Better loan errors PR3088
• Add `lang-item` paths PR3068
• Asm generic il codegen PR3060
• borrowck: Added location support to BIR nodes PR3013
• Fix LIBS override in upstream Issue 3120

Contributors this month

• Liam Naddell
• Raiki Tamura
• Mahad Muhammad
• Kushal Pal
• Jasmine Tang
• Thomas Schwinge
• Marc Poulhiès
• Pierre-Emmanuel Patry
• Arthur Cohen

Overall Task Status

Test Cases

Bugs

Milestones Progress

Planned Activities

• Start adding Detailed Changelogs to the reports again
• Be more public about the compiler’s progress

Risks

There have been no changes to the Risk table this month

Detailed changelog