Getting Involved — LLVM 20.1.8 documentation

# Getting Involved

LLVM welcomes contributions of all kinds. To get started, please review the following topics:

Contributing to LLVM

  An overview on how to contribute to LLVM.

LLVM Developer Policy

  The LLVM project’s policy towards developers and their contributions.

LLVM Code-Review Policy and Practices

  The LLVM project’s code-review process.

LLVM Community Support Policy

  The LLVM support policy for core and non-core components.

Sphinx Quickstart Template

  A template + tutorial for writing new Sphinx documentation. It is meant to be read in source form.

How to submit an LLVM bug report

  Instructions for properly submitting information about any bugs you run into in the LLVM system.

LLVM Bug Life Cycle

  Describes how bugs are reported, triaged and closed.

LLVM Coding Standards

  Details the LLVM coding standards and provides useful information on writing efficient C++ code.

LLVM GitHub User Guide

  Describes how to use the llvm-project repository and code reviews on GitHub.

Bisecting LLVM code

  Describes how to use `git bisect` on LLVM’s repository.

Policies on git repositories

  Collection of policies around the git repositories.

## Development Process

Information about LLVM’s development process.

Creating an LLVM Project

  How-to guide and templates for new projects that use the LLVM infrastructure. The templates (directory organization, Makefiles, and test tree) allow the project code to be located outside (or inside) the `llvm/` tree, while using LLVM header files and libraries.

How To Release LLVM To The Public

  This is a guide to preparing LLVM releases. Most developers can ignore it.

How To Validate a New Release

  This is a guide to validate a new release, during the release process. Most developers can ignore it.

How To Add Your Build Configuration To LLVM Buildbot Infrastructure

  Instructions for adding new builder to LLVM buildbot master.

Release notes for the current release

  This describes new features, known bugs, and other limitations.

## Forums & Mailing Lists

If you can’t find what you need in these docs, try consulting the Discourse forums. There are also commit mailing lists for all commits to the LLVM Project. The LLVM Community Code of Conduct applies to all these forums and mailing lists.

LLVM Discourse

  The forums for all things LLVM and related sub-projects. There are categories and subcategories for a wide variety of areas within LLVM. You can also view tags or search for a specific topic.

Commits Archive (llvm-commits)

  This list contains all commit messages that are made when LLVM developers commit code changes to the repository. It also serves as a forum for patch review (i.e. send patches here). It is useful for those who want to stay on the bleeding edge of LLVM development. This list is very high volume.

Bugs & Patches Archive (llvm-bugs)

  This list gets emailed every time a bug is opened and closed. It is higher volume than the LLVM-dev list.

LLVM Announcements

  If you just want project wide announcements such as releases, developers meetings, or blog posts, then you should check out the Announcement category on LLVM Discourse.

## Online Sync-Ups

A number of regular calls are organized on specific topics. It should be expected that the range of topics will change over time. At the time of writing, the following sync-ups are organized. The LLVM Community Code of Conduct applies to all online sync-ups.

If you’d like to organize a new sync-up, please add the info in the table below. Please also create a calendar event for it and invite calendar@llvm.org to the event, so that it’ll show up on the LLVM community calendar. Please see Guidance on what to put into LLVM community calendar invites for more guidance on what to add to your calendar invite.

Table 125 LLVM regular sync-up calls
Topic | Frequency | Calendar link | Minutes/docs link
--- | --- | --- | ---
Loop Optimization Working Group | Every first Wednesday of the month | ics | Minutes/docs
RISC-V | Every 2 weeks on Thursday | ics gcal | Minutes/docs
ML Guided Compiler Optimizations | Monthly |  | Minutes/docs
LLVM security group | Monthly, every 3rd Tuesday | ics gcal | Minutes/docs
CIRCT | Weekly, on Wednesday |  | Minutes/docs
flang | Multiple meeting series, documented here |  |
OpenMP | Multiple meeting series, documented here |  |
LLVM Alias Analysis | Every 4 weeks on Tuesdays | ics | Minutes/docs
LLVM Pointer Authentication | Every month on Mondays | ics | Minutes/docs
LLVM Embedded Toolchains | Every 4 weeks on Thursdays | ics gcal | Minutes/docs
Clang C and C++ Language Working Group | 1st and 3rd Wednesday of the month | gcal | Minutes/docs
LLVM SPIR-V Backend Working Group | Every week on Monday |  | Meeting details/agenda
SYCL Upstream Working Group | Every 2 weeks on Mondays | gcal | Meeting details/agenda
Floating Point Working Group | Every 3rd Wednesday of the month | ics gcal | Meeting details/agenda:
Vectorizer Improvement Working Group | Every 3rd Thursday of the month | ics | Meeting details/agenda:

For event owners, our Discord bot also supports sending automated announcements of upcoming sync-ups. Please see the Discord bot event pings section for info.

### Past online sync-ups

Some online sync-ups are no longer happening. We keep pointing to them here to keep track of the meeting notes and in case anyone would want to revive them in the future.

Table 126 LLVM no-longer-happening sync-up calls
Topic | Frequency | Calendar link | Minutes/docs link
--- | --- | --- | ---
Scalable Vectors and Arm SVE | Monthly, every 3rd Tuesday | ics gcal | Minutes/docs
MemorySSA in LLVM | Every 8 weeks on Mondays | ics gcal | Minutes/docs
GlobalISel | Every 2nd Tuesday of the month | gcal | Meeting details/agenda
Vector Predication | Every 2 weeks on Tuesdays, 3pm UTC |  | Minutes/docs
MLIR design meetings | Weekly, on Thursdays |  | Minutes/docs

## Office hours

A number of experienced LLVM contributors make themselves available for a chat on a regular schedule, to anyone who is looking for some guidance. Please find the list of who is available when, through which medium, and what their area of expertise is. Don’t be too shy to dial in!

Office hours are also listed on the LLVM community calendar. Of course, people take time off from time to time, so if you dial in and you don’t find anyone present, chances are they happen to be off that day.

The LLVM Community Code of Conduct applies to all office hours.

Table 127 LLVM office hours
Name | In-scope topics | When? | Where? | Languages
--- | --- | --- | --- | ---
Kristof Beyls | General questions on how to contribute to LLVM; organizing meetups; submitting talks; and other general LLVM-related topics. Arm/AArch64 codegen. LLVM security group. LLVM Office Hours. | Every 2nd and 4th Wednesday of the month at 9.30am CET, for 30 minutes. ics | Jitsi | English, Flemish, Dutch
Alina Sbirlea | General questions on how to contribute to LLVM; women in compilers; MemorySSA, BatchAA, various loop passes, new pass manager. | Monthly, 2nd Tuesdays, 10.00am PT/7:00pm CET, for 30 minutes. ics gcal | GoogleMeet | English, Romanian
Aaron Ballman (he/him) | Clang internals; frontend attributes; clang-tidy; clang-query; AST matchers | Monthly, 2nd Monday and 3rd Friday of the month at 10:00am Eastern and again at 2:00pm Eastern, for 60 minutes. ics gcal | GoogleMeet | English, Norwegian (not fluently)
Johannes Doerfert (he/him) | OpenMP, LLVM-IR, interprocedural optimizations, Attributor, workshops, research, … | Every week, Wednesdays 9:30am (Pacific Time), for 1 hour. ics | MS Teams | English, German
Tobias Grosser | General questions on how to contribute to LLVM/MLIR, Polly, Loop Optimization, FPL, Research in LLVM, PhD in CS, Summer of Code. | Monthly, last Monday of the month at 18:00 London time (typically 9am PT), for 30 minutes. | Video Call | English, German, Spanish, French
Alexey Bader | SYCL compiler, offload tools, OpenCL and SPIR-V, how to contribute. | Monthly, 2nd Monday of the month at 9:30am PT, for 30 minutes. | GoogleMeet | English, Russian
Maksim Panchenko | BOLT internals, IR, new passes, proposals, etc. | Monthly, 2nd Wednesday of the month at 11:00am PT, for 30 minutes. | Zoom | English, Russian
Quentin Colombet (he/him) | LLVM/MLIR; Codegen (Instruction selection (GlobalISel/SDISel), Machine IR, Register allocation, etc.); Optimizations; MCA | Monthly, 1st Wednesday of the month at 8.00am PT, for 30 minutes. ics gcal | Google meet | English, French
Phoebe Wang (she/her) | X86 backend, General questions to X86, women in compilers. | Monthly, 3rd Wednesday of the month at 8:30am Beijing time, for 30 minutes. | MS Teams | English, Chinese
Amara Emerson | GlobalISel questions. | Monthly, 4th Wednesday of the month at 9:30am PT, for 30 minutes. | Google meet | English
Maksim Levental and Jeremy Kun | MLIR newcomers and general discussion (livestreamed) | Every two weeks, Wednesdays at 2:00pm US Pacific, for 90 minutes. | Livestream chat or Google meet | English
Renato Golin | General LLVM, MLIR & Linalg, distributed computing, research, socials. | Every first Friday of the month, 14:00 UK time, for 60 minutes. | Google meet | English, Portuguese
Rotating hosts | Getting Started, beginner questions, new contributors. | Every Tuesday at 2 PM ET (11 AM PT), for 30 minutes. | Google meet | English

For event owners, our Discord bot also supports sending automated announcements of upcoming office hours. Please see the Discord bot event pings section for info.

### Guidance for office hours hosts

- If you’re interested in becoming an office hours host, please add your information to the list above. Please create a calendar event for it and invite calendar@llvm.org to the event so that it’ll show up on the LLVM community calendar. Please see Guidance on what to put into LLVM community calendar invites for more guidance on what to add to your calendar invite.

- When starting an office hours session, if you haven’t set up the Discord bot integration, consider typing something like “Hi, I’m available for chats in the next half hour at video chat URL. I’m looking forward to having conversations on the video chat or here.” on the #office-hours Discord channel.

  Doing this can help:

    - overcome potential anxiety to call in for a first time,

    - people who prefer to first exchange a few messages through text chat before dialing in, and

    - remind the wider community that office hours do exist.

- If you decide to no longer host office hours, please do remove your entry from the list above.

## Discord

Users and developers of the LLVM project (including subprojects such as Clang) can be found on the community’s Discord chat server. The server is actively moderated.

The #buildbot-status channel has a bot for LLVM buildbot status changes. The bot will update the channel with a link to a build bot when a build goes from passing to failing and again when the build goes from failing back to passing. It is a great way to actively monitor the status of the build.

The bot also supports @mention-ing you when your email appears on a blamelist. For more details, DM `help` to the bot.

### Discord bot event pings

Our Discord bot supports automatically sending messages about upcoming events on the LLVM community calendar to Discord. This behavior is controlled on a per-event basis, by metadata in the event’s description. Each piece of metadata should be on its own line in the event description.

The currently supported metadata is:

- `discord-bot-event-type` - Required. Specifies the event type. Valid values are `office-hours` and `sync-up`.

- `discord-bot-channels-to-mention` - Sometimes required. A comma-separated list of Discord channels to post notifications in. If your `discord-bot-event-type` is `office-hours`, the `#office-hours` channel will be implicitly appended to this list (ergo, you don’t need to specify this item). Otherwise, you must specify a value here.

- `discord-bot-mention` - Optional. A comma-separated list of people to ping on each event notification. All names mentioned must be Discord usernames, and must have a leading `@`. e.g., `@foo, @bar`.

- `discord-bot-reminder-time-before-start` - Optional. The number of minutes before the beginning of an event to send a ping. This should be formatted as an integer. Defaults to 30.

- `discord-bot-message` - Optional. Text to append to all event pings.

An example of an event description with valid metadata is:

    Regular office hours to chat with people about LLVM! We can help with
    questions, troubleshooting bugs, etc.

    discord-bot-channels-to-mention: #beginners, #foo
    discord-bot-event-type: office-hours
    discord-bot-mention: @gburgessiv, @bar
    discord-bot-message: Come join us for office hours!
    discord-bot-reminder-time-before-start: 5

This metadata will prompt the Discord bot to:

- send pings 5 minutes before the given event starts, mentioning `@gburgessiv` and `@bar` in the ping

- send the pings to the `#beginners`, `#foo`, and `#office-hours` channels

- include the text “Come join us for office hours!” in the ping

A few minutes before sending a ping, the bot will double-check that the event hasn’t been cancelled.

If you need help troubleshooting, or have feature requests/questions, please feel free to ping @gburgessiv!

## Meetups and social events

Besides developer meetings and conferences, there are several user groups called LLVM Socials. We greatly encourage you to join one in your city. Or start a new one if there is none:

How to start LLVM Social in your town

## Community wide proposals

Proposals for massive changes in how the community behaves and how the work flow can be better.

Moving LLVM Projects to GitHub

  Proposal to move from SVN/Git to GitHub.

Bugpoint Redesign

  Design doc for a redesign of the Bugpoint tool.

Test-Suite Extensions

  Proposals for additional benchmarks/programs for llvm’s test-suite.

Variable Names Plan

  Proposal to change the variable names coding standard.

Vector Predication Roadmap

  Proposal for predicated vector instructions in LLVM.

## LLVM community calendar

We aim to maintain a public calendar view of all events happening in the LLVM community such as Online Sync-Ups and Office hours. The calendar can be found at https://calendar.google.com/calendar/u/0/embed?src=calendar@llvm.org and can also be seen inline below:

Note that the web view of the LLVM community calendar shows events in Coordinated Universal Time (UTC). If you use Google Calendar, consider subscribing to it with the + button in the bottom-right corner to view all events in your local timezone alongside your other calendars.

### Guidance on what to put into LLVM community calendar invites

To add your event, create a calendar event for it and invite calendar@llvm.org on it. Your event should then show up on the community calendar.

Please put the following pieces of information in your calendar invite:

- Write a single paragraph describing what the event is about. Include things such as who the event is for and what sort of topics are discussed.

- State explicitly that the LLVM Community Code of Conduct applies to this event.

- Make it clear who:

  - the organizer is.

  - the person to contact is in case of any code-of-conduct issues. Typically, this would be the organizer.

- If you have meeting minutes for your event, add a pointer to where those live. A good place for meeting minutes could be as a post on LLVM Discourse.

- If you’re hosting a sync-up or office hours event and would like it to be announced by the Discord bot, add the relevant metadata (full descriptions available in the Discord bot event pings section).

An example invite looks as follows

    This event is a meetup for all developers of LLDB. Meeting agendas are posted
    on discourse before the event.

    Attendees are required to adhere to the LLVM Code of Conduct
    (https://llvm.org/docs/CodeOfConduct.html). For any Code of Conduct reports,
    please contact the organizers, and also email conduct@llvm.org.

    Agenda/Meeting Minutes: Link to minutes

    Organizer(s): First Surname (name@email.com)

    discord-bot-channels-to-mention: #lldb
    discord-bot-event-type: sync-up
    discord-bot-mention: @host-username, @another-host
    discord-bot-message: Come join us to chat about LLDB!
    discord-bot-reminder-time-before-start: 30