169 lines · html
1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"2 "http://www.w3.org/TR/html4/strict.dtd">3<html>4<head>5 <META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">6 <title>Clang - Get Involved</title>7 <link type="text/css" rel="stylesheet" href="menu.css">8 <link type="text/css" rel="stylesheet" href="content.css">9</head>10<body>11 12<!--#include virtual="menu.html.incl"-->13 14<div id="content">15 16<h1>Getting Involved with the Clang Project</h1>17 18<p>Once you have <a href="get_started.html">checked out and built</a> clang and19played around with it, you might be wondering what you can do to make it better20and contribute to its development. Alternatively, maybe you just want to follow21the development of the project to see it progress.22</p>23 24<h2>Contribute</h2>25 26See the <a href="hacking.html">hacking</a> document for information on how27to author patches.28 29<h2>Follow what's going on</h2>30 31<p>Clang is a subproject of the <a href="https://llvm.org">LLVM Project</a>32and has a Discourse forum and mailing list:</p>33 34<ul>35<li><a href="https://discourse.llvm.org/c/clang/6">Clang Frontend Discourse forum</a> -36This forum is for discussions related to Clang (questions and answers, design37discussions, RFCs, etc).</li>38 39<li><a href="https://discord.gg/xS7Z362">Discord chat</a> - Real-time chat for40discussions related to Clang (primarily for questions and answers).</li>41 42<li>Regular meetings are held on the43<a href="https://drive.google.com/file/d/1S7V0MHP4xMs1yUQ9Gv9LHn5bwDfFVapn/view?usp=sharing">44first and third Wednesday</a> of each month to discuss C and C++45standards-related activities happening within the Clang community. These46meetings are a way to coordinate efforts between implementers and provide47updates on how standards activities are going. Meeting agendas and minutes are48available49<a href="https://docs.google.com/document/d/1x5-RbOC6-jnI_NcJ9Dp4pSmGhhNe7lUevuWUIB46TeM/edit?usp=sharing">50here<a>.51</li>52 53<li><a href="https://llvm.org/docs/GettingInvolved.html#office-hours">Clang office hours</a> -54People within the community hold dedicated office hours at different points55during the month, which is a great way opportunity for getting questions56answered, having more in-depth design discussions, or learning about what's57going on in the community in general.</li>58 59<li><a href="https://lists.llvm.org/mailman/listinfo/cfe-commits">cfe-commits60</a> - Historical record of commits to Clang and contains early community patch61review commentary.</li>62 63</ul>64 65<p>The most common way to talk with other developers on the project is through66the <a href="https://discourse.llvm.org/c/clang/6">Clang Frontend Discourse forum67</a>. The clang forum is a very friendly place and we welcome newcomers. The68forum is archived so you can browse through previous discussions or follow69development on the web if you prefer.</p>70 71<p>If you're looking for something to work on, check out our <a72href="OpenProjects.html">Open Projects</a> page or look through the <a73href="https://github.com/llvm/llvm-project/issues/">LLVM bug tracker</a>.</p>74 75<h2 id="criteria">Contributing Extensions to Clang</h2>76 77<p>Clang is designed to support experimentation,78allowing programmers to easily extend the compiler to support great79new language features and tools. At some point, the authors of these80extensions may propose that the extensions become a part of Clang81itself, to benefit the whole Clang community. However, extensions82(particularly language extensions) have long-term maintenance costs83for Clang. The benefits of the extension need to be evaluated against84these costs. The Clang project uses the following criteria for this85evaluation:</p>86<p>87<ol>88 <li>Evidence of a significant user community: This is based on a number of89 factors, including an existing user community, the perceived likelihood that90 users would adopt such a feature if it were available, and any secondary91 effects that come from, e.g., a library adopting the feature and providing92 benefits to its users.</li>93 94 <li>A specific need to reside within the Clang tree: There are some extensions95 that would be better expressed as a separate tool, and should remain as96 separate tools even if they end up being hosted as part of the LLVM umbrella97 project.</li>98 99 <li>A specification: The specification must be sufficient to understand the100 design of the feature as well as interpret the meaning of specific examples.101 The specification should be detailed enough that another compiler vendor102 could implement the feature.</li>103 104 <li>Representation within the appropriate governing organization: For105 extensions to a language governed by a standards committee (C, C++, OpenCL),106 the extension itself must have an active proposal and proponent within that107 committee and have a reasonable chance of acceptance. Clang should drive the108 standard, not diverge from it. This criterion does not apply to all109 extensions, since some extensions fall outside of the realm of the standards110 bodies.</li>111 112 <li>A long-term support plan: increasingly large or complex extensions to113 Clang need matching commitments to supporting them over time, including114 improving their implementation and specification as Clang evolves. The115 capacity of the contributor to make that commitment is as important as the116 commitment itself.</li>117 118 <li>A high-quality implementation: The implementation must fit well into119 Clang's architecture, follow LLVM's coding conventions, and meet Clang's120 quality standards, including diagnostics and complete AST121 representations. This is particularly important for language extensions,122 because users will learn how those extensions work through the behavior of the123 compiler.</li>124 125 <li>A test suite: Extensive testing is crucial to ensure that the language126 extension is not broken by ongoing maintenance in Clang. The test suite127 should be complete enough that another compiler vendor could conceivably128 validate their implementation of the feature against it.</li>129 130 <li>A support story for other impacted projects within the monorepo: If the131 extension can impact other parts of the project (libc++, lldb, compiler-rt,132 etc), the proposal needs to document the impact for these projects to fully133 support the extension and what level of support is expected. The impacted134 project communities need to agree with that plan.</li>135</ol>136</p>137<p>138The Clang community uses an RFC process to evaluate potential extensions for139inclusion in the tool. First, write a post in the <code>Clang Frontend</code>140category of <a href="https://discourse.llvm.org/c/clang/6">Discourse</a>. The141title should include <code>[RFC]</code> so it is clear that it is a proposed142change. The post should have detailed information about the change itself, the143motivation for needing the change, how it addresses the criteria listed above,144and any other relevant details the community should be aware of.145</p>146<p>147The community will discuss the proposal in Discourse, asking questions about148the proposal to improve their understanding and giving support or dissent for149the idea. Eventually, consensus will be determined as to whether the proposal150should proceed or be rejected. If a proposal receives little or no feedback,151that typically means that the proposal is rejected due to lack of interest.152</p>153<p>154Sometimes, a consensus position is unclear and the proposal author will need155additional guidance on what next steps to take. In such a case, the Clang Area156Team may get involved. The Clang Area Team secretary will proactively look for157RFCs that appear to not have a clear path forward to add them to the team's158agenda. If anyone would like to put an RFC onto the team's agenda explicitly,159they can tag any one of the <a href="https://github.com/llvm/llvm-project/blob/main/clang/AreaTeamMembers.txt">160Clang Area Team</a> members in a comment on the RFC to get their attention. The161area team will host a meeting to discuss the RFC and determine next steps for162the proposal. In the event no clear community consensus position seems likely163to ever form, the Clang Area Team will make a final judgement call on whether164the RFC will proceed or not. <!-- TODO: link to area team processes -->165</p>166</div>167</body>168</html>169