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.

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 129 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
Vectorizer Improvement Working Group	3rd Tuesday 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 130 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 131 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!

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

Documentation