Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 74699fda1598c3c30c1a237fe7e75b11d1a53596 / . / docs / DeveloperPolicy.html
blob: f92d76d5dfb8cce8a7f0c330f3466aa8967e94e6 [file] [log] [blame]
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
Bill Wendling19a8dca2009-04-05 12:38:44 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]6 <title>LLVM Developer Policy</title>
7 <link rel="stylesheet" href="llvm.css" type="text/css">
8</head>
9<body>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]10
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]11<h1>LLVM Developer Policy</h1>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]12<ol>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]13 <li><a href="#introduction">Introduction</a></li>
Chris Lattner1ff20cd2007-02-19 06:05:58 +0000[diff] [blame]14 <li><a href="#policies">Developer Policies</a>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]15 <ol>
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame]16 <li><a href="#informed">Stay Informed</a></li>
17 <li><a href="#patches">Making a Patch</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]18 <li><a href="#reviews">Code Reviews</a></li>
Chris Lattnere268a402007-12-03 19:00:47 +0000[diff] [blame]19 <li><a href="#owners">Code Owners</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]20 <li><a href="#testcases">Test Cases</a></li>
Chris Lattner1acdc952007-02-19 05:49:11 +0000[diff] [blame]21 <li><a href="#quality">Quality</a></li>
22 <li><a href="#commitaccess">Obtaining Commit Access</a></li>
Chris Lattner1ff20cd2007-02-19 06:05:58 +0000[diff] [blame]23 <li><a href="#newwork">Making a Major Change</a></li>
24 <li><a href="#incremental">Incremental Development</a></li>
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]25 <li><a href="#attribution">Attribution of Changes</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]26 </ol></li>
Chris Lattner793aa382007-02-19 06:19:16 +0000[diff] [blame]27 <li><a href="#clp">Copyright, License, and Patents</a>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]28 <ol>
29 <li><a href="#copyright">Copyright</a></li>
30 <li><a href="#license">License</a></li>
Chris Lattner1ff20cd2007-02-19 06:05:58 +0000[diff] [blame]31 <li><a href="#patents">Patents</a></li>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]32 </ol></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]33</ol>
Chris Lattner2ae49dd2007-02-19 06:24:23 +0000[diff] [blame]34<div class="doc_author">Written by the LLVM Oversight Team</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]35
36<!--=========================================================================-->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]37<h2><a name="introduction">Introduction</a></h2>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]38<!--=========================================================================-->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]39<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]40<p>This document contains the LLVM Developer Policy which defines the project's
41 policy towards developers and their contributions. The intent of this policy
42 is to eliminate miscommunication, rework, and confusion that might arise from
43 the distributed nature of LLVM's development. By stating the policy in clear
44 terms, we hope each developer can know ahead of time what to expect when
Chris Lattnerb742ff02010-09-02 00:09:17 +0000[diff] [blame]45 making LLVM contributions. This policy covers all llvm.org subprojects,
46 including Clang, LLDB, etc.</p>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]47<p>This policy is also designed to accomplish the following objectives:</p>
48
49<ol>
50 <li>Attract both users and developers to the LLVM project.</li>
51
52 <li>Make life as simple and easy for contributors as possible.</li>
53
54 <li>Keep the top of Subversion trees as stable as possible.</li>
55</ol>
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]56
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]57<p>This policy is aimed at frequent contributors to LLVM. People interested in
58 contributing one-off patches can do so in an informal way by sending them to
59 the
60 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits
61 mailing list</a> and engaging another developer to see it through the
62 process.</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]63</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]64
65<!--=========================================================================-->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]66<h2><a name="policies">Developer Policies</a></h2>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]67<!--=========================================================================-->
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]68<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]69<p>This section contains policies that pertain to frequent LLVM developers. We
70 always welcome <a href="#patches">one-off patches</a> from people who do not
71 routinely contribute to LLVM, but we expect more from frequent contributors
72 to keep the system as efficient as possible for everyone. Frequent LLVM
73 contributors are expected to meet the following requirements in order for
74 LLVM to maintain a high standard of quality.<p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]75
76<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]77<h3><a name="informed">Stay Informed</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]78<div>
Chris Lattnerb742ff02010-09-02 00:09:17 +0000[diff] [blame]79<p>Developers should stay informed by reading at least the "dev" mailing list
80 for the projects you are interested in, such as
81 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvmdev</a> for
82 LLVM, <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">cfe-dev</a>
83 for Clang, or <a
84 href="http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev">lldb-dev</a>
85 for LLDB. If you are doing anything more than just casual work on LLVM, it
86 is suggested that you also subscribe to the "commits" mailing list for the
87 subproject you're interested in, such as
88 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>,
89 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits">cfe-commits</a>,
90 or <a href="http://lists.cs.uiuc.edu/mailman/listinfo/lldb-commits">lldb-commits</a>.
91 Reading the "commits" list and paying attention to changes being made by
92 others is a good way to see what other people are interested in and watching
93 the flow of the project as a whole.</p>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]94
95<p>We recommend that active developers register an email account with
96 <a href="http://llvm.org/bugs/">LLVM Bugzilla</a> and preferably subscribe to
97 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs">llvm-bugs</a>
Chris Lattnerb742ff02010-09-02 00:09:17 +0000[diff] [blame]98 email list to keep track of bugs and enhancements occurring in LLVM. We
99 really appreciate people who are proactive at catching incoming bugs in their
100 components and dealing with them promptly.</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]101</div>
102
103<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]104<h3><a name="patches">Making a Patch</a></h3>
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame]105
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]106<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]107<p>When making a patch for review, the goal is to make it as easy for the
108 reviewer to read it as possible. As such, we recommend that you:</p>
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame]109
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]110<ol>
111 <li>Make your patch against the Subversion trunk, not a branch, and not an old
Chris Lattner9b96e802009-10-10 21:37:16 +0000[diff] [blame]112 version of LLVM. This makes it easy to apply the patch. For information
113 on how to check out SVN trunk, please see the <a
114 href="GettingStarted.html#checkout">Getting Started Guide</a>.</li>
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame]115
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]116 <li>Similarly, patches should be submitted soon after they are generated. Old
117 patches may not apply correctly if the underlying code changes between the
118 time the patch was created and the time it is applied.</li>
119
Dan Gohmanc1076ea2010-08-04 16:07:22 +0000[diff] [blame]120 <li>Patches should be made with <tt>svn diff</tt>, or similar. If you use
121 a different tool, make sure it uses the <tt>diff -u</tt> format and
122 that it doesn't contain clutter which makes it hard to read.</li>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]123
Dan Gohmanc1076ea2010-08-04 16:07:22 +0000[diff] [blame]124 <li>If you are modifying generated files, such as the top-level
125 <tt>configure</tt> script, please separate out those changes into
126 a separate patch from the rest of your changes.</li>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]127</ol>
Chris Lattner0cca50c2007-02-19 06:57:16 +0000[diff] [blame]128
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]129<p>When sending a patch to a mailing list, it is a good idea to send it as an
130 <em>attachment</em> to the message, not embedded into the text of the
131 message. This ensures that your mailer will not mangle the patch when it
132 sends it (e.g. by making whitespace changes or by wrapping lines).</p>
133
134<p><em>For Thunderbird users:</em> Before submitting a patch, please open
135 <em>Preferences &#8594; Advanced &#8594; General &#8594; Config Editor</em>,
136 find the key <tt>mail.content_disposition_type</tt>, and set its value to
137 <tt>1</tt>. Without this setting, Thunderbird sends your attachment using
138 <tt>Content-Disposition: inline</tt> rather than <tt>Content-Disposition:
139 attachment</tt>. Apple Mail gamely displays such a file inline, making it
140 difficult to work with for reviewers using that program.</p>
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame]141</div>
142
143<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]144<h3><a name="reviews">Code Reviews</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]145<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]146<p>LLVM has a code review policy. Code review is one way to increase the quality
147 of software. We generally follow these policies:</p>
Chris Lattner0cca50c2007-02-19 06:57:16 +0000[diff] [blame]148
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]149<ol>
150 <li>All developers are required to have significant changes reviewed before
151 they are committed to the repository.</li>
152
153 <li>Code reviews are conducted by email, usually on the llvm-commits
154 list.</li>
155
156 <li>Code can be reviewed either before it is committed or after. We expect
157 major changes to be reviewed before being committed, but smaller changes
158 (or changes where the developer owns the component) can be reviewed after
159 commit.</li>
160
161 <li>The developer responsible for a code change is also responsible for making
162 all necessary review-related changes.</li>
163
164 <li>Code review can be an iterative process, which continues until the patch
165 is ready to be committed.</li>
166</ol>
167
168<p>Developers should participate in code reviews as both reviewers and
169 reviewees. If someone is kind enough to review your code, you should return
170 the favor for someone else. Note that anyone is welcome to review and give
171 feedback on a patch, but only people with Subversion write access can approve
172 it.</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]173</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]174
175<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]176<h3><a name="owners">Code Owners</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]177<div>
Chris Lattnere268a402007-12-03 19:00:47 +0000[diff] [blame]178
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]179<p>The LLVM Project relies on two features of its process to maintain rapid
180 development in addition to the high quality of its source base: the
181 combination of code review plus post-commit review for trusted maintainers.
182 Having both is a great way for the project to take advantage of the fact that
183 most people do the right thing most of the time, and only commit patches
184 without pre-commit review when they are confident they are right.</p>
Chris Lattnere268a402007-12-03 19:00:47 +0000[diff] [blame]185
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]186<p>The trick to this is that the project has to guarantee that all patches that
187 are committed are reviewed after they go in: you don't want everyone to
188 assume someone else will review it, allowing the patch to go unreviewed. To
189 solve this problem, we have a notion of an 'owner' for a piece of the code.
190 The sole responsibility of a code owner is to ensure that a commit to their
191 area of the code is appropriately reviewed, either by themself or by someone
192 else. The current code owners are:</p>
Chris Lattnere268a402007-12-03 19:00:47 +0000[diff] [blame]193
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]194<ol>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]195 <li><b>Evan Cheng</b>: Code generator and all targets.</li>
196
Chris Lattner5ce89812010-09-23 17:27:54 +0000[diff] [blame]197 <li><b>Greg Clayton</b>: LLDB.</li>
198
199 <li><b>Doug Gregor</b>: Clang Frontend Libraries.</li>
200
201 <li><b>Howard Hinnant</b>: libc++.</li>
Chris Lattneraf5bd672009-09-16 05:36:07 +0000[diff] [blame]202
Chris Lattnerb2030432009-09-16 05:37:13 +0000[diff] [blame]203 <li><b>Anton Korobeynikov</b>: Exception handling, debug information, and
204 Windows codegen.</li>
205
Chris Lattnerf86a7782009-09-16 05:42:12 +0000[diff] [blame]206 <li><b>Ted Kremenek</b>: Clang Static Analyzer.</li>
207
Chris Lattner941f4cd2009-09-16 05:36:54 +0000[diff] [blame]208 <li><b>Chris Lattner</b>: Everything not covered by someone else.</li>
Chris Lattneraf5bd672009-09-16 05:36:07 +0000[diff] [blame]209
John McCall74699fd2011-08-02 01:38:19 +0000[diff] [blame^]210 <li><b>John McCall</b>: Clang LLVM IR generation.</li>
211
Chris Lattneraf5bd672009-09-16 05:36:07 +0000[diff] [blame]212 <li><b>Duncan Sands</b>: llvm-gcc 4.2.</li>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]213</ol>
Chris Lattnere268a402007-12-03 19:00:47 +0000[diff] [blame]214
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]215<p>Note that code ownership is completely different than reviewers: anyone can
216 review a piece of code, and we welcome code review from anyone who is
217 interested. Code owners are the "last line of defense" to guarantee that all
218 patches that are committed are actually reviewed.</p>
Chris Lattnere268a402007-12-03 19:00:47 +0000[diff] [blame]219
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]220<p>Being a code owner is a somewhat unglamorous position, but it is incredibly
221 important for the ongoing success of the project. Because people get busy,
222 interests change, and unexpected things happen, code ownership is purely
223 opt-in, and anyone can choose to resign their "title" at any time. For now,
224 we do not have an official policy on how one gets elected to be a code
225 owner.</p>
Chris Lattnere268a402007-12-03 19:00:47 +0000[diff] [blame]226</div>
227
Chris Lattnere268a402007-12-03 19:00:47 +0000[diff] [blame]228<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]229<h3><a name="testcases">Test Cases</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]230<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]231<p>Developers are required to create test cases for any bugs fixed and any new
232 features added. Some tips for getting your testcase approved:</p>
233
234<ol>
235 <li>All feature and regression test cases are added to the
236 <tt>llvm/test</tt> directory. The appropriate sub-directory should be
237 selected (see the <a href="TestingGuide.html">Testing Guide</a> for
238 details).</li>
239
240 <li>Test cases should be written in <a href="LangRef.html">LLVM assembly
241 language</a> unless the feature or regression being tested requires
242 another language (e.g. the bug being fixed or feature being implemented is
243 in the llvm-gcc C++ front-end, in which case it must be written in
244 C++).</li>
245
246 <li>Test cases, especially for regressions, should be reduced as much as
247 possible, by <a href="Bugpoint.html">bugpoint</a> or manually. It is
248 unacceptable to place an entire failing program into <tt>llvm/test</tt> as
249 this creates a <i>time-to-test</i> burden on all developers. Please keep
250 them short.</li>
251</ol>
Chris Lattner0cca50c2007-02-19 06:57:16 +0000[diff] [blame]252
Chris Lattnerb742ff02010-09-02 00:09:17 +0000[diff] [blame]253<p>Note that llvm/test and clang/test are designed for regression and small
254 feature tests only. More extensive test cases (e.g., entire applications,
255 benchmarks, etc)
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]256 should be added to the <tt>llvm-test</tt> test suite. The llvm-test suite is
257 for coverage (correctness, performance, etc) testing, not feature or
258 regression testing.</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]259</div>
260
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]261<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]262<h3><a name="quality">Quality</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]263<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]264<p>The minimum quality standards that any change must satisfy before being
265 committed to the main development branch are:</p>
266
267<ol>
268 <li>Code must adhere to the <a href="CodingStandards.html">LLVM Coding
269 Standards</a>.</li>
270
271 <li>Code must compile cleanly (no errors, no warnings) on at least one
272 platform.</li>
273
274 <li>Bug fixes and new features should <a href="#testcases">include a
275 testcase</a> so we know if the fix/feature ever regresses in the
276 future.</li>
277
Chris Lattnerb742ff02010-09-02 00:09:17 +0000[diff] [blame]278 <li>Code must pass the <tt>llvm/test</tt> test suite.</li>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]279
280 <li>The code must not cause regressions on a reasonable subset of llvm-test,
281 where "reasonable" depends on the contributor's judgement and the scope of
282 the change (more invasive changes require more testing). A reasonable
283 subset might be something like
284 "<tt>llvm-test/MultiSource/Benchmarks</tt>".</li>
285</ol>
286
287<p>Additionally, the committer is responsible for addressing any problems found
288 in the future that the change is responsible for. For example:</p>
289
290<ul>
291 <li>The code should compile cleanly on all supported platforms.</li>
292
293 <li>The changes should not cause any correctness regressions in the
294 <tt>llvm-test</tt> suite and must not cause any major performance
295 regressions.</li>
296
297 <li>The change set should not cause performance or correctness regressions for
298 the LLVM tools.</li>
299
300 <li>The changes should not cause performance or correctness regressions in
301 code compiled by LLVM on all applicable targets.</li>
302
303 <li>You are expected to address any <a href="http://llvm.org/bugs/">bugzilla
304 bugs</a> that result from your change.</li>
305</ul>
Chris Lattner39582bd2007-02-19 05:47:13 +0000[diff] [blame]306
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]307<p>We prefer for this to be handled before submission but understand that it
Chris Lattnerd7f10d32009-08-01 19:25:25 +0000[diff] [blame]308 isn't possible to test all of this for every submission. Our build bots and
309 nightly testing infrastructure normally finds these problems. A good rule of
310 thumb is to check the nightly testers for regressions the day after your
311 change. Build bots will directly email you if a group of commits that
312 included yours caused a failure. You are expected to check the build bot
313 messages to see if they are your fault and, if so, fix the breakage.</p>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]314
315<p>Commits that violate these quality standards (e.g. are very broken) may be
316 reverted. This is necessary when the change blocks other developers from
317 making progress. The developer is welcome to re-commit the change after the
318 problem has been fixed.</p>
Chris Lattner39582bd2007-02-19 05:47:13 +0000[diff] [blame]319</div>
320
321<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]322<h3><a name="commitaccess">Obtaining Commit Access</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]323<div>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]324
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]325<p>We grant commit access to contributors with a track record of submitting high
326 quality patches. If you would like commit access, please send an email to
327 <a href="mailto:sabre@nondot.org">Chris</a> with the following
328 information:</p>
Chris Lattnerbebcdabd82007-12-03 00:36:20 +0000[diff] [blame]329
330<ol>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]331 <li>The user name you want to commit with, e.g. "hacker".</li>
332
Chris Lattnerbebcdabd82007-12-03 00:36:20 +0000[diff] [blame]333 <li>The full name and email address you want message to llvm-commits to come
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]334 from, e.g. "J. Random Hacker &lt;hacker@yoyodyne.com&gt;".</li>
335
Chris Lattnerbebcdabd82007-12-03 00:36:20 +0000[diff] [blame]336 <li>A "password hash" of the password you want to use, e.g. "2ACR96qjUqsyM".
337 Note that you don't ever tell us what your password is, you just give it
338 to us in an encrypted form. To get this, run "htpasswd" (a utility that
339 comes with apache) in crypt mode (often enabled with "-d"), or find a web
340 page that will do it for you.</li>
341</ol>
342
343<p>Once you've been granted commit access, you should be able to check out an
344 LLVM tree with an SVN URL of "https://username@llvm.org/..." instead of the
345 normal anonymous URL of "http://llvm.org/...". The first time you commit
346 you'll have to type in your password. Note that you may get a warning from
347 SVN about an untrusted key, you can ignore this. To verify that your commit
348 access works, please do a test commit (e.g. change a comment or add a blank
349 line). Your first commit to a repository may require the autogenerated email
350 to be approved by a mailing list. This is normal, and will be done when
351 the mailing list owner has time.</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]352
353<p>If you have recently been granted commit access, these policies apply:</p>
Chris Lattnerbebcdabd82007-12-03 00:36:20 +0000[diff] [blame]354
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]355<ol>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]356 <li>You are granted <i>commit-after-approval</i> to all parts of LLVM. To get
357 approval, submit a <a href="#patches">patch</a> to
358 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>.
359 When approved you may commit it yourself.</li>
360
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]361 <li>You are allowed to commit patches without approval which you think are
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]362 obvious. This is clearly a subjective decision &mdash; we simply expect
363 you to use good judgement. Examples include: fixing build breakage,
364 reverting obviously broken patches, documentation/comment changes, any
365 other minor changes.</li>
366
367 <li>You are allowed to commit patches without approval to those portions of
368 LLVM that you have contributed or maintain (i.e., have been assigned
369 responsibility for), with the proviso that such commits must not break the
370 build. This is a "trust but verify" policy and commits of this nature are
371 reviewed after they are committed.</li>
372
373 <li>Multiple violations of these policies or a single egregious violation may
374 cause commit access to be revoked.</li>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]375</ol>
Chris Lattner0cca50c2007-02-19 06:57:16 +0000[diff] [blame]376
377<p>In any case, your changes are still subject to <a href="#reviews">code
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]378 review</a> (either before or after they are committed, depending on the
379 nature of the change). You are encouraged to review other peoples' patches
380 as well, but you aren't required to.</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]381</div>
382
383<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]384<h3><a name="newwork">Making a Major Change</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]385<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]386<p>When a developer begins a major new project with the aim of contributing it
387 back to LLVM, s/he should inform the community with an email to
388 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvmdev</a>
389 email list, to the extent possible. The reason for this is to:
390
391<ol>
392 <li>keep the community informed about future changes to LLVM, </li>
393
394 <li>avoid duplication of effort by preventing multiple parties working on the
395 same thing and not knowing about it, and</li>
396
397 <li>ensure that any technical issues around the proposed work are discussed
398 and resolved before any significant work is done.</li>
399</ol>
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]400
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]401<p>The design of LLVM is carefully controlled to ensure that all the pieces fit
402 together well and are as consistent as possible. If you plan to make a major
403 change to the way LLVM works or want to add a major new extension, it is a
404 good idea to get consensus with the development community before you start
405 working on it.</p>
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]406
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]407<p>Once the design of the new feature is finalized, the work itself should be
408 done as a series of <a href="#incremental">incremental changes</a>, not as a
409 long-term development branch.</p>
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]410</div>
411
412<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]413<h3><a name="incremental">Incremental Development</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]414<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]415<p>In the LLVM project, we do all significant changes as a series of incremental
416 patches. We have a strong dislike for huge changes or long-term development
417 branches. Long-term development branches have a number of drawbacks:</p>
418
419<ol>
420 <li>Branches must have mainline merged into them periodically. If the branch
421 development and mainline development occur in the same pieces of code,
422 resolving merge conflicts can take a lot of time.</li>
423
424 <li>Other people in the community tend to ignore work on branches.</li>
425
426 <li>Huge changes (produced when a branch is merged back onto mainline) are
427 extremely difficult to <a href="#reviews">code review</a>.</li>
428
429 <li>Branches are not routinely tested by our nightly tester
430 infrastructure.</li>
431
432 <li>Changes developed as monolithic large changes often don't work until the
433 entire set of changes is done. Breaking it down into a set of smaller
434 changes increases the odds that any of the work will be committed to the
435 main repository.</li>
436</ol>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]437
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]438<p>To address these problems, LLVM uses an incremental development style and we
439 require contributors to follow this practice when making a large/invasive
440 change. Some tips:</p>
441
442<ul>
443 <li>Large/invasive changes usually have a number of secondary changes that are
444 required before the big change can be made (e.g. API cleanup, etc). These
445 sorts of changes can often be done before the major change is done,
446 independently of that work.</li>
447
448 <li>The remaining inter-related work should be decomposed into unrelated sets
449 of changes if possible. Once this is done, define the first increment and
450 get consensus on what the end goal of the change is.</li>
451
452 <li>Each change in the set can be stand alone (e.g. to fix a bug), or part of
453 a planned series of changes that works towards the development goal.</li>
454
455 <li>Each change should be kept as small as possible. This simplifies your work
456 (into a logical progression), simplifies code review and reduces the
457 chance that you will get negative feedback on the change. Small increments
458 also facilitate the maintenance of a high quality code base.</li>
459
460 <li>Often, an independent precursor to a big change is to add a new API and
461 slowly migrate clients to use the new API. Each change to use the new API
462 is often "obvious" and can be committed without review. Once the new API
463 is in place and used, it is much easier to replace the underlying
464 implementation of the API. This implementation change is logically
465 separate from the API change.</li>
466</ul>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]467
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]468<p>If you are interested in making a large change, and this scares you, please
469 make sure to first <a href="#newwork">discuss the change/gather consensus</a>
470 then ask about the best way to go about making the change.</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]471</div>
472
473<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]474<h3><a name="attribution">Attribution of Changes</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]475<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]476<p>We believe in correct attribution of contributions to their contributors.
477 However, we do not want the source code to be littered with random
478 attributions "this code written by J. Random Hacker" (this is noisy and
479 distracting). In practice, the revision control system keeps a perfect
480 history of who changed what, and the CREDITS.txt file describes higher-level
481 contributions. If you commit a patch for someone else, please say "patch
482 contributed by J. Random Hacker!" in the commit message.</p>
Chris Lattnerab2b10c2007-12-29 19:56:08 +0000[diff] [blame]483
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]484<p>Overall, please do not add contributor names to the source code.</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]485</div>
486
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]487</div>
488
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]489<!--=========================================================================-->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]490<h2>
Chris Lattner793aa382007-02-19 06:19:16 +0000[diff] [blame]491 <a name="clp">Copyright, License, and Patents</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]492</h2>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]493<!--=========================================================================-->
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]494
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]495<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]496<p>This section addresses the issues of copyright, license and patents for the
497 LLVM project. Currently, the University of Illinois is the LLVM copyright
498 holder and the terms of its license to LLVM users and developers is the
499 <a href="http://www.opensource.org/licenses/UoI-NCSA.php">University of
500 Illinois/NCSA Open Source License</a>.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]501
502<div class="doc_notes">
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]503<p style="text-align:center;font-weight:bold">NOTE: This section deals with
504 legal matters but does not provide legal advice. We are not lawyers, please
505 seek legal counsel from an attorney.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]506</div>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]507
508<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]509<h3><a name="copyright">Copyright</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]510<div>
Chris Lattner305915b2008-05-20 20:06:53 +0000[diff] [blame]511
Chris Lattnerc226fc82010-09-27 21:17:15 +0000[diff] [blame]512<p>The LLVM project does not require copyright assignments, which means that the
513 copyright for the code in the project is held by its respective contributors
514 who have each agreed to release their contributed code under the terms of the
515 <a href="#license">LLVM License</a>.</p>
516
517<p>An implication of this is that the LLVM license is unlikely to ever change:
518 changing it would require tracking down all the contributors to LLVM and
519 getting them to agree that a license change is acceptable for their
520 contribution. Since there are no plans to change the license, this is not a
521 cause for concern.</p>
522
523<p>As a contributor to the project, this means that you (or your company) retain
524 ownership of the code you contribute, that it cannot be used in a way that
525 contradicts the license (which is a liberal BSD-style license), and that the
526 license for your contributions won't change without your approval in the
527 future.</p>
528
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]529</div>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]530
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]531<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]532<h3><a name="license">License</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]533<div>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]534<p>We intend to keep LLVM perpetually open source and to use a liberal open
Chris Lattnerac139f12010-11-16 21:32:53 +0000[diff] [blame]535 source license. All of the code in LLVM is available under the
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]536 <a href="http://www.opensource.org/licenses/UoI-NCSA.php">University of
Dan Gohman621a4152010-02-26 20:18:32 +0000[diff] [blame]537 Illinois/NCSA Open Source License</a>, which boils down to this:</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]538
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]539<ul>
540 <li>You can freely distribute LLVM.</li>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]541 <li>You must retain the copyright notice if you redistribute LLVM.</li>
Chris Lattnerac139f12010-11-16 21:32:53 +0000[diff] [blame]542 <li>Binaries derived from LLVM must reproduce the copyright notice (e.g. in an
543 included readme file).</li>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]544 <li>You can't use our names to promote your LLVM derived products.</li>
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]545 <li>There's no warranty on LLVM at all.</li>
546</ul>
547
548<p>We believe this fosters the widest adoption of LLVM because it <b>allows
549 commercial products to be derived from LLVM</b> with few restrictions and
550 without a requirement for making any derived works also open source (i.e.
551 LLVM's license is not a "copyleft" license like the GPL). We suggest that you
552 read the <a href="http://www.opensource.org/licenses/UoI-NCSA.php">License</a>
553 if further clarification is needed.</p>
Chris Lattnerac139f12010-11-16 21:32:53 +0000[diff] [blame]554
555<p>In addition to the UIUC license, the runtime library components of LLVM
556 (<b>compiler_rt and libc++</b>) are also licensed under the <a
557 href="http://www.opensource.org/licenses/mit-license.php">MIT license</a>,
558 which does not contain the binary redistribution clause. As a user of these
559 runtime libraries, it means that you can choose to use the code under either
560 license (and thus don't need the binary redistribution clause), and as a
561 contributor to the code that you agree that any contributions to these
562 libraries be licensed under both licenses. We feel that this is important
563 for runtime libraries, because they are implicitly linked into applications
564 and therefore should not subject those applications to the binary
565 redistribution clause. This also means that it is ok to move code from (e.g.)
566 libc++ to the LLVM core without concern, but that code cannot be moved from
567 the LLVM core to libc++ without the copyright owner's permission.
568</p>
569
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]570<p>Note that the LLVM Project does distribute llvm-gcc, <b>which is GPL.</b>
571 This means that anything "linked" into llvm-gcc must itself be compatible
572 with the GPL, and must be releasable under the terms of the GPL. This
573 implies that <b>any code linked into llvm-gcc and distributed to others may
574 be subject to the viral aspects of the GPL</b> (for example, a proprietary
575 code generator linked into llvm-gcc must be made available under the GPL).
576 This is not a problem for code already distributed under a more liberal
577 license (like the UIUC license), and does not affect code generated by
578 llvm-gcc. It may be a problem if you intend to base commercial development
579 on llvm-gcc without redistributing your source code.</p>
580
581<p>We have no plans to change the license of LLVM. If you have questions or
582 comments about the license, please contact the
Chris Lattnerac139f12010-11-16 21:32:53 +0000[diff] [blame]583 <a href="mailto:llvmdev@cs.uiuc.edu">LLVM Developer's Mailing List</a>.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]584</div>
Chris Lattner1ff20cd2007-02-19 06:05:58 +0000[diff] [blame]585
586<!-- _______________________________________________________________________ -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]587<h3><a name="patents">Patents</a></h3>
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]588<div>
Chris Lattnerb87fb2a2007-02-19 06:13:50 +0000[diff] [blame]589<p>To the best of our knowledge, LLVM does not infringe on any patents (we have
590 actually removed code from LLVM in the past that was found to infringe).
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]591 Having code in LLVM that infringes on patents would violate an important goal
592 of the project by making it hard or impossible to reuse the code for
Chris Lattnerd0742ce2007-02-19 06:15:33 +0000[diff] [blame]593 arbitrary purposes (including commercial use).</p>
Chris Lattnerb87fb2a2007-02-19 06:13:50 +0000[diff] [blame]594
595<p>When contributing code, we expect contributors to notify us of any potential
Bill Wendling78c8fce2009-04-05 12:37:44 +0000[diff] [blame]596 for patent-related trouble with their changes. If you or your employer own
597 the rights to a patent and would like to contribute code to LLVM that relies
598 on it, we require that the copyright owner sign an agreement that allows any
599 other user of LLVM to freely use your patent. Please contact
600 the <a href="mailto:llvm-oversight@cs.uiuc.edu">oversight group</a> for more
Chris Lattnerb87fb2a2007-02-19 06:13:50 +0000[diff] [blame]601 details.</p>
Chris Lattner1ff20cd2007-02-19 06:05:58 +0000[diff] [blame]602</div>
603
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]604</div>
605
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]606<!-- *********************************************************************** -->
607<hr>
608<address>
609 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]610 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]611 <a href="http://validator.w3.org/check/referer"><img
Misha Brukmanf00ddb02008-12-11 18:23:24 +0000[diff] [blame]612 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Chris Lattnerd0742ce2007-02-19 06:15:33 +0000[diff] [blame]613 Written by the
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]614 <a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]615 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]616 Last modified: $Date$
617</address>
618</body>
619</html>