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 meantto be read in source form.
- How to submit an LLVM bug report
Instructions for properly submitting information about any bugs you run intoin 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 writingefficient 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
gitbisecton 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 thatuse the LLVMinfrastructure. The templates (directory organization, Makefiles, and testtree) 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 theDiscourse forums. There are also commit mailing lists for all commits to the LLVM Project.TheLLVM 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 developerscommit code changes to the repository. It also serves as a forum forpatch review (i.e. send patches here). It is useful for those who want tostay on the bleeding edge of LLVM development. This list is very highvolume.
- Bugs & Patches Archive (llvm-bugs)
This list gets emailed every time a bug is opened and closed. It ishigher 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 beexpected that the range of topics will change over time. At the time ofwriting, the following sync-ups are organized.TheLLVM 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 tablebelow. Please also create a calendar event for it and invitecalendar@llvm.orgto the event, so that it’ll show up on theLLVM community calendar.Please seeGuidance on what to put into LLVM community calendar invites for more guidance onwhat to add to your calendar invite.
Topic | Frequency | Calendar link | Minutes/docs link |
|---|---|---|---|
Loop Optimization Working Group | Every first Wednesday of the month | ||
RISC-V | Every 2 weeks on Thursday | ||
ML Guided Compiler Optimizations | Monthly | ||
Monthly, every 3rd Tuesday | |||
Weekly, on Wednesday | |||
flang | Multiple meeting series,documented here | ||
OpenMP | Multiple meeting series,documented here | ||
LLVM Alias Analysis | Every 4 weeks on Tuesdays | ||
LLVM Pointer Authentication | Every month on Mondays | ||
LLVM Embedded Toolchains | Every 4 weeks on Thursdays | ||
Clang C and C++ Language Working Group | 1st and 3rd Wednesday of the month | ||
LLVM SPIR-V Backend Working Group | Every week on Monday | ||
SYCL Upstream Working Group | Every 2 weeks on Mondays | ||
Vectorizer Improvement Working Group | 3rd Tuesday of the month |
For event owners, our Discord bot also supports sending automated announcementsof upcoming sync-ups. Please see theDiscord bot event pings section forinfo.
Past online sync-ups¶
Some online sync-ups are no longer happening. We keep pointing to them here tokeep track of the meeting notes and in case anyone would want to revive them inthe future.
Topic | Frequency | Calendar link | Minutes/docs link |
|---|---|---|---|
Scalable Vectors and Arm SVE | Monthly, every 3rd Tuesday | ||
MemorySSA in LLVM | Every 8 weeks on Mondays | ||
GlobalISel | Every 2nd Tuesday of the month | ||
Vector Predication | Every 2 weeks on Tuesdays, 3pm UTC | ||
MLIR design meetings | Weekly, on Thursdays |
Office hours¶
A number of experienced LLVM contributors make themselves available for a chaton a regular schedule, to anyone who is looking for some guidance. Please findthe list of who is available when, through which medium, and what their area ofexpertise is. Don’t be too shy to dial in!
Office hours are also listed on theLLVM community calendar. Of course,people take time off from time to time, so if you dial in and you don’t findanyone present, chances are they happen to be off that day.
TheLLVM Community Code of Conduct applies to all 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/AArch64codegen. LLVM security group. LLVM Office Hours. | Every 2nd and 4th Wednesday of the month at 9.30am CET, for 30 minutes.ics | 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.icsgcal | 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.icsgcal | 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 | 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. | 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. | English, Russian | |
Maksim Panchenko | BOLT internals, IR, new passes, proposals, etc. | Monthly, 2nd Wednesday of the month at 11:00am PT, for 30 minutes. | 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.icsgcal | 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. | English, Chinese | |
Amara Emerson | GlobalISel questions. | Monthly, 4th Wednesday of the month at 9:30am PT, for 30 minutes. | 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 orGoogle 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. | English, Portuguese | |
Rotating hosts | Getting Started, beginner questions, new contributors. | Every Tuesday at 2 PM ET (11 AM PT), for 30 minutes. | English |
For event owners, our Discord bot also supports sending automated announcementsof upcoming office hours. Please see theDiscord bot event pings sectionfor info.
Guidance for office hours hosts¶
If you’re interested in becoming an office hours host, please add yourinformation to the list above. Please create a calendar event for it andinvitecalendar@llvm.org to the event so that it’ll show up on theLLVM community calendar.Please seeGuidance on what to put into LLVM community calendar invites for more guidance onwhat to add to your calendar invite.
When starting an office hours session, if you haven’t set up the Discord botintegration, consider typing something like “Hi, I’m available for chats inthe next half hour at video chat URL.I’m looking forward to havingconversations 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 chatbefore 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 entryfrom the list above.
Discord¶
Users and developers of the LLVM project (including subprojects such as Clang)can be found on the community’sDiscordchat server. The server is actively moderated.
The #buildbot-status channel has a bot forLLVM buildbot status changes. Thebot will update the channel with a link to a build bot when a build goes frompassing 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, DMhelp to the bot.
Discord bot event pings¶
Our Discord bot supports automatically sending messages about upcoming eventsonthe LLVM community calendarto Discord. This behavior is controlled on a per-event basis, by metadata in theevent’s description. Each piece of metadata should be on its own line in theevent description.
The currently supported metadata is:
discord-bot-event-type-Required. Specifies the event type. Validvalues areoffice-hoursandsync-up.discord-bot-channels-to-mention-Sometimes required. Acomma-separated list of Discord channels to post notifications in. If yourdiscord-bot-event-typeisoffice-hours, the#office-hourschannelwill be implicitly appended to this list (ergo, you don’t need to specify thisitem). Otherwise, you must specify a value here.discord-bot-mention-Optional. A comma-separated list of people toping on each event notification. All names mentioned must be Discordusernames, and must have a leading@. e.g.,@foo,@bar.discord-bot-reminder-time-before-start-Optional. The number ofminutes before the beginning of an event to send a ping. This should beformatted 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 withquestions, troubleshooting bugs, etc.discord-bot-channels-to-mention: #beginners, #foodiscord-bot-event-type: office-hoursdiscord-bot-mention: @gburgessiv, @bardiscord-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
@gburgessivand@barin the pingsend the pings to the
#beginners,#foo, and#office-hourschannelsinclude 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 eventhasn’t been cancelled.
If you need help troubleshooting, or have feature requests/questions, pleasefeel free to ping @gburgessiv!
Meetups and social events¶
Besides developermeetings and conferences,there are several user groups calledLLVM Socials. We greatly encourage you tojoin one in your city. Or start a new one if there is none:
Community wide proposals¶
Proposals for massive changes in how the community behaves and how the work flowcan 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 LLVMcommunity such asOnline Sync-Ups andOffice hours. The calendarcan be found athttps://calendar.google.com/calendar/u/0/embed?src=calendar@llvm.org and canalso be seen inline below:
Note that the web view of the LLVM community calendar shows events inCoordinated Universal Time (UTC). If you use Google Calendar, considersubscribing to it with the + button in the bottom-right corner to view allevents 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 invitecalendar@llvm.orgon 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 thingssuch as who the event is for and what sort of topics are discussed.
State explicitly that theLLVM 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 beannounced by the Discord bot, add the relevant metadata (full descriptionsavailable in theDiscord bot event pings section).
An example invite looks as follows
This event is a meetup for all developers of LLDB. Meeting agendas are postedon 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 minutesOrganizer(s): First Surname (name@email.com)discord-bot-channels-to-mention: #lldbdiscord-bot-event-type: sync-updiscord-bot-mention: @host-username, @another-hostdiscord-bot-message: Come join us to chat about LLDB!discord-bot-reminder-time-before-start: 30