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5 <title>LLVM Developer Policy</title>
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7</head>
8<body>
9
10<div class="doc_title">LLVM Developer Policy</div>
11<ol>
12 <li><a href="#introduction">Introduction</a></li>
13 <li><a href="#policies">Developer Policies</a>
14 <ol>
15 <li><a href="#informed">Stay Informed</a></li>
16 <li><a href="#patches">Making a Patch</a></li>
17 <li><a href="#reviews">Code Reviews</a></li>
Chris Lattner85d1d0b2007-12-03 19:00:47 +0000[diff] [blame]18 <li><a href="#owners">Code Owners</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]19 <li><a href="#testcases">Test Cases</a></li>
20 <li><a href="#quality">Quality</a></li>
21 <li><a href="#commitaccess">Obtaining Commit Access</a></li>
22 <li><a href="#newwork">Making a Major Change</a></li>
23 <li><a href="#incremental">Incremental Development</a></li>
24 <li><a href="#attribution">Attribution of Changes</a></li>
25 </ol></li>
26 <li><a href="#clp">Copyright, License, and Patents</a>
27 <ol>
28 <li><a href="#copyright">Copyright</a></li>
29 <li><a href="#license">License</a></li>
30 <li><a href="#patents">Patents</a></li>
31 <li><a href="#devagree">Developer Agreements</a></li>
32 </ol></li>
33</ol>
34<div class="doc_author">Written by the LLVM Oversight Team</div>
35
36<!--=========================================================================-->
37<div class="doc_section"><a name="introduction">Introduction</a></div>
38<!--=========================================================================-->
39<div class="doc_text">
40 <p>This document contains the LLVM Developer Policy which defines the
41 project's policy towards developers and their contributions. The intent of
42 this policy is to eliminate mis-communication, rework, and confusion that
43 might arise from the distributed nature of LLVM's development. By stating
44 the policy in clear terms, we hope each developer can know ahead of time
45 what to expect when making LLVM contributions.</p>
46 <p>This policy is also designed to accomplish the following objectives:</p>
47 <ol>
48 <li>Attract both users and developers to the LLVM project.</li>
49 <li>Make life as simple and easy for contributors as possible.</li>
50 <li>Keep the top of Subversion trees as stable as possible.</li>
51 </ol>
52
53 <p>This policy is aimed at frequent contributors to LLVM. People interested in
54 contributing one-off patches can do so in an informal way by sending them to
55 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">
56 llvm-commits mailing list</a> and engaging another developer to see it through
57 the process.</p>
58
59</div>
60
61<!--=========================================================================-->
62<div class="doc_section"><a name="policies">Developer Policies</a></div>
63<!--=========================================================================-->
64<div class="doc_text">
65 <p>This section contains policies that pertain to frequent LLVM
66 developers. We always welcome <a href="#patches">one-off patches</a> from
67 people who do not routinely contribute to LLVM, but we expect more from
68 frequent contributors to keep the system as efficient as possible for
69 everyone.
70 Frequent LLVM contributors are expected to meet the following requirements in
71 order for LLVM to maintain a high standard of quality.<p>
72</div>
73
74<!-- _______________________________________________________________________ -->
75<div class="doc_subsection"> <a name="informed">Stay Informed</a> </div>
76<div class="doc_text">
77 <p>Developers should stay informed by reading at least the
78 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvmdev</a>
79 email list. If you are doing anything more than just casual work on LLVM,
80 it is suggested that you also subscribe to the
81 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>
82 list and pay attention to changes being made by others.</p>
83 <p>We recommend that active developers register an email account with
84 <a href="http://llvm.org/bugs/">LLVM Bugzilla</a> and preferably subscribe to
85 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs">llvm-bugs</a>
86 email list to keep track of bugs and enhancements occurring in LLVM.</p>
87</div>
88
89<!-- _______________________________________________________________________ -->
90<div class="doc_subsection"> <a name="patches">Making a Patch</a></div>
91
92<div class="doc_text">
93
94<p>When making a patch for review, the goal is to make it as easy for the
95 reviewer to read it as possible. As such, we recommend that you:</p>
96 <ol>
97 <li>Make your patch against the Subversion trunk, not a branch, and not an
98 old version of LLVM. This makes it easy to apply the patch.</li>
99
100 <li>Similarly, patches should be submitted soon after they are generated.
101 Old patches may not apply correctly if the underlying code changes between
102 the time the patch was created and the time it is applied.</li>
103
104 <li>Patches should be made with this command:
105 <pre>svn diff -x -u</pre>
106 or with the utility <tt>utils/mkpatch</tt>, which makes it easy to read the
107 diff.</li>
108
109 <li>Patches should not include differences in generated code such as the
110 code generated by <tt>flex</tt>, <tt>bison</tt> or <tt>tblgen</tt>. The
111 <tt>utils/mkpatch</tt> utility takes care of this for you.</li>
112
113 </ol>
114
115 <p>When sending a patch to a mailing list, it is a good idea to send it as an
116 <em>attachment</em> to the message, not embedded into the text of the
117 message. This ensures that your mailer will not mangle the patch when it
118 sends it (e.g. by making whitespace changes or by wrapping lines).</p>
Gordon Henriksen83cae732008-06-26 22:58:37 +0000[diff] [blame]119
120 <p><em>For Thunderbird users:</em> Before submitting a patch, please open
121 <em>Preferences &#8594; Advanced &#8594; General &#8594; Config Editor</em>,
122 find the key <tt>mail.content_disposition_type</tt>, and set its value to
123 <tt>1</tt>. Without this setting, Thunderbird sends your attachment using
124 <tt>Content-Disposition: inline</tt> rather than <tt>Content-Disposition:
125 attachment</tt>. Apple Mail gamely displays such a file inline, making it
126 difficult to work with for reviewers using that program.</p>
127</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]128</div>
129
130<!-- _______________________________________________________________________ -->
131<div class="doc_subsection"> <a name="reviews">Code Reviews</a></div>
132<div class="doc_text">
133 <p>LLVM has a code review policy. Code review is one way to increase the
134 quality of software. We generally follow these policies:</p>
135 <ol>
136 <li>All developers are required to have significant changes reviewed
137 before they are committed to the repository.</li>
138 <li>Code reviews are conducted by email, usually on the llvm-commits
139 list.</li>
140 <li>Code can be reviewed either before it is committed or after. We expect
141 major changes to be reviewed before being committed, but smaller
142 changes (or changes where the developer owns the component) can be
143 reviewed after commit.</li>
144 <li>The developer responsible for a code change is also responsible for
145 making all necessary review-related changes.</li>
146 <li>Code review can be an iterative process, which continues until the patch
147 is ready to be committed.</li>
148 </ol>
149
150 <p>Developers should participate in code reviews as both reviewers and
151 reviewees. If someone is kind enough to review your code, you should
152 return the favor for someone else. Note that anyone is welcome to review
153 and give feedback on a patch, but only people with Subversion write access
154 can approve it.</p>
155
156</div>
157
158<!-- _______________________________________________________________________ -->
Chris Lattner85d1d0b2007-12-03 19:00:47 +0000[diff] [blame]159<div class="doc_subsection"> <a name="owners">Code Owners</a></div>
160<div class="doc_text">
161
162 <p>The LLVM Project relies on two features of its process to maintain rapid
163 development in addition to the high quality of its source base: the
164 combination of code review plus post-commit review for trusted maintainers.
165 Having both is a great way for the project to take advantage of the fact
166 that most people do the right thing most of the time, and only commit
167 patches without pre-commit review when they are confident they are
168 right.</p>
169
170 <p>The trick to this is that the project has to guarantee that all patches
171 that are committed are reviewed after they go in: you don't want everyone
172 to assume someone else will review it, allowing the patch to go unreviewed.
173 To solve this problem, we have a notion of an 'owner' for a piece of the
174 code. The sole responsibility of a code owner is to ensure that a commit
175 to their area of the code is appropriately reviewed, either by themself or
176 by someone else. The current code owners are:</p>
177
178 <ol>
179 <li><b>Anton Korobeynikov</b>: Exception handling, debug information, and
180 Windows codegen.</li>
181 <li><b>Duncan Sands</b>: llvm-gcc 4.2.</li>
182 <li><b>Evan Cheng</b>: Code generator and all targets.</li>
183 <li><b>Chris Lattner</b>: Everything else.</li>
184 </ol>
185
186 <p>Note that code ownership is completely different than reviewers: anyone can
187 review a piece of code, and we welcome code review from anyone who is
188 interested. Code owners are the "last line of defense" to guarantee that
189 all patches that are committed are actually reviewed.</p>
190
191 <p>Being a code owner is a somewhat unglamorous position, but it is incredibly
192 important for the ongoing success of the project. Because people get busy,
193 interests change, and unexpected things happen, code ownership is purely
194 opt-in, and anyone can choose to resign their "title" at any time. For now,
195 we do not have an official policy on how one gets elected to be a code
196 owner.
197 </p>
198
199</div>
200
201
202<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]203<div class="doc_subsection"> <a name="testcases">Test Cases</a></div>
204<div class="doc_text">
205 <p>Developers are required to create test cases for any bugs fixed and any new
206 features added. Some tips for getting your testcase approved:</p>
207 <ol>
208 <li>All feature and regression test cases are added to the
209 <tt>llvm/test</tt> directory. The appropriate sub-directory should be
210 selected (see the <a href="TestingGuide.html">Testing Guide</a> for
211 details).</li>
212 <li>Test cases should be written in
213 <a href="LangRef.html">LLVM assembly language</a> unless the
214 feature or regression being tested requires another language (e.g. the
215 bug being fixed or feature being implemented is in the llvm-gcc C++
216 front-end, in which case it must be written in C++).</li>
217 <li>Test cases, especially for regressions, should be reduced as much as
218 possible, by <a href="Bugpoint.html">bugpoint</a> or
219 manually. It is unacceptable
220 to place an entire failing program into <tt>llvm/test</tt> as this creates
221 a <i>time-to-test</i> burden on all developers. Please keep them short.</li>
222 </ol>
223
224 <p>Note that llvm/test is designed for regression and small feature tests
225 only. More extensive test cases (e.g., entire applications, benchmarks,
226 etc) should be added to the <tt>llvm-test</tt> test suite. The llvm-test
227 suite is for coverage (correctness, performance, etc) testing, not feature
228 or regression testing.</p>
229</div>
230
231<!-- _______________________________________________________________________ -->
232<div class="doc_subsection"> <a name="quality">Quality</a></div>
233<div class="doc_text">
234 <p>The minimum quality standards that any change must satisfy before being
235 committed to the main development branch are:</p>
236 <ol>
237 <li>Code must adhere to the
238 <a href="CodingStandards.html">LLVM Coding Standards</a>.</li>
239 <li>Code must compile cleanly (no errors, no warnings) on at least one
240 platform.</li>
241 <li>Bug fixes and new features should <a href="#testcases">include a
242 testcase</a> so we know if the fix/feature ever regresses in the
243 future.</li>
244 <li>Code must pass the dejagnu (<tt>llvm/test</tt>) test suite.</li>
245 <li>The code must not cause regressions on a reasonable subset of llvm-test,
246 where "reasonable" depends on the contributor's judgement and the scope
247 of the change (more invasive changes require more testing). A reasonable
248 subset is "<tt>llvm-test/MultiSource/Benchmarks</tt>".</li>
249 </ol>
250 <p>Additionally, the committer is responsible for addressing any problems
251 found in the future that the change is responsible for. For example:</p>
252 <ul>
253 <li>The code should compile cleanly on all supported platforms.</li>
254 <li>The changes should not cause any correctness regressions in the
255 <tt>llvm-test</tt> suite and must not cause any major performance
256 regressions.</li>
257 <li>The change set should not cause performance or correctness regressions
258 for the LLVM tools.</li>
259 <li>The changes should not cause performance or correctness regressions in
260 code compiled by LLVM on all applicable targets.</li>
261 <li>You are expected to address any <a href="http://llvm.org/bugs/">bugzilla
262 bugs</a> that result from your change.</li>
263 </ul>
264
265 <p>We prefer for this to be handled before submission but understand that it
266 isn't possible to test all of this for every submission. Our nightly
267 testing
268 infrastructure normally finds these problems. A good rule of thumb is to
269 check the nightly testers for regressions the day after your change.</p>
270
271 <p>Commits that violate these quality standards (e.g. are very broken) may
272 be reverted. This is necessary when the change blocks other developers from
273 making progress. The developer is welcome to re-commit the change after
274 the problem has been fixed.</p>
275</div>
276
277<!-- _______________________________________________________________________ -->
278<div class="doc_subsection">
279 <a name="commitaccess">Obtaining Commit Access</a></div>
280<div class="doc_text">
281
282<p>
283We grant commit access to contributors with a track record of submitting high
Chris Lattner8e823442007-12-03 00:36:20 +0000[diff] [blame]284quality patches. If you would like commit access, please send an email to
285<a href="mailto:sabre@nondot.org">Chris</a> with the following information:</p>
286
287<ol>
288 <li>The user name you want to commit with, e.g. "sabre".</li>
289 <li>The full name and email address you want message to llvm-commits to come
290 from, e.g. "Chris Lattner &lt;sabre@nondot.org&gt;".</li>
291 <li>A "password hash" of the password you want to use, e.g. "2ACR96qjUqsyM".
292 Note that you don't ever tell us what your password is, you just give it
293 to us in an encrypted form. To get this, run "htpasswd" (a utility that
294 comes with apache) in crypt mode (often enabled with "-d"), or find a web
295 page that will do it for you.</li>
296</ol>
297
298<p>Once you've been granted commit access, you should be able to check out an
299 LLVM tree with an SVN URL of "https://username@llvm.org/..." instead of the
300 normal anonymous URL of "http://llvm.org/...". The first time you commit
301 you'll have to type in your password. Note that you may get a warning from
302 SVN about an untrusted key, you can ignore this. To verify that your commit
303 access works, please do a test commit (e.g. change a comment or add a blank
304 line). Your first commit to a repository may require the autogenerated email
305 to be approved by a mailing list. This is normal, and will be done when
306 the mailing list owner has time.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]307
308<p>If you have recently been granted commit access, these policies apply:</p>
Chris Lattner8e823442007-12-03 00:36:20 +0000[diff] [blame]309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]310<ol>
311 <li>You are granted <i>commit-after-approval</i> to all parts of LLVM.
312 To get approval, submit a <a href="#patches">patch</a> to
313 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">
314 llvm-commits</a>. When approved you may commit it yourself.</li>
315 <li>You are allowed to commit patches without approval which you think are
316 obvious. This is clearly a subjective decision &mdash; we simply expect you
317 to use good judgement. Examples include: fixing build breakage, reverting
318 obviously broken patches, documentation/comment changes, any other minor
319 changes.</li>
320 <li>You are allowed to commit patches without approval to those portions
321 of LLVM that you have contributed or maintain (i.e., have been assigned
322 responsibility for), with the proviso that such commits must not break the
323 build. This is a "trust but verify" policy and commits of this nature are
324 reviewed after they are committed.</li>
325 <li>Multiple violations of these policies or a single egregious violation
326 may cause commit access to be revoked.</li>
327</ol>
328
329<p>In any case, your changes are still subject to <a href="#reviews">code
330review</a> (either before or after they are committed, depending on the nature
331of the change). You are encouraged to review other peoples' patches as well,
332but you aren't required to.</p>
333
334</div>
335
336<!-- _______________________________________________________________________ -->
337<div class="doc_subsection"> <a name="newwork">Making a Major Change</a></div>
338<div class="doc_text">
339 <p>When a developer begins a major new project with the aim of contributing
340 it back to LLVM, s/he should inform the community with an email to
341 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvmdev</a>
342 email list, to the extent possible. The reason for this is to:
343 <ol>
344 <li>keep the community informed about future changes to LLVM, </li>
345 <li>avoid duplication of effort by preventing multiple parties working on
346 the same thing and not knowing about it, and</li>
347 <li>ensure that any technical issues around the proposed work are
348 discussed and resolved before any significant work is done.</li>
349 </ol>
350
351 <p>The design of LLVM is carefully controlled to ensure that all the pieces
352 fit together well and are as consistent as possible. If you plan to make a
353 major change to the way LLVM works or want to add a major new extension, it
354 is a good idea to get consensus with the development
355 community before you start working on it.</p>
356
357 <p>Once the design of the new feature is finalized, the work itself should be
358 done as a series of <a href="#incremental">incremental changes</a>, not as
359 a long-term development branch.</p>
360
361</div>
362
363<!-- _______________________________________________________________________ -->
364<div class="doc_subsection"> <a name="incremental">Incremental Development</a>
365</div>
366<div class="doc_text">
367 <p>In the LLVM project, we do all significant changes as a series of
368 incremental patches. We have a strong dislike for huge changes or
369 long-term development branches. Long-term development branches have a
370 number of drawbacks:</p>
371
372 <ol>
373 <li>Branches must have mainline merged into them periodically. If the branch
374 development and mainline development occur in the same pieces of code,
375 resolving merge conflicts can take a lot of time.</li>
376 <li>Other people in the community tend to ignore work on branches.</li>
377 <li>Huge changes (produced when a branch is merged back onto mainline) are
378 extremely difficult to <a href="#reviews">code review</a>.</li>
379 <li>Branches are not routinely tested by our nightly tester
380 infrastructure.</li>
381 <li>Changes developed as monolithic large changes often don't work until the
382 entire set of changes is done. Breaking it down into a set of smaller
383 changes increases the odds that any of the work will be committed to the
384 main repository.</li>
385 </ol>
386
387 <p>
388 To address these problems, LLVM uses an incremental development style and we
389 require contributors to follow this practice when making a large/invasive
390 change. Some tips:</p>
391
392 <ul>
393 <li>Large/invasive changes usually have a number of secondary changes that
394 are required before the big change can be made (e.g. API cleanup, etc).
395 These sorts of changes can often be done before the major change is done,
396 independently of that work.</li>
397 <li>The remaining inter-related work should be decomposed into unrelated
398 sets of changes if possible. Once this is done, define the first increment
399 and get consensus on what the end goal of the change is.</li>
400
401 <li>Each change in the set can be stand alone (e.g. to fix a bug), or part
402 of a planned series of changes that works towards the development goal.</li>
403
404 <li>Each change should be kept as small as possible. This simplifies your
405 work (into a logical progression), simplifies code review and reduces the
406 chance that you will get negative feedback on the change. Small increments
407 also facilitate the maintenance of a high quality code base.</li>
408
409 <li>Often, an independent precursor to a big change is to add a new API and
410 slowly migrate clients to use the new API. Each change to use the new
411 API is often "obvious" and can be committed without review. Once the
412 new API is in place and used, it is much easier to replace the
413 underlying implementation of the API. This implementation change is
414 logically separate from the API change.</li>
415 </ul>
416
417 <p>If you are interested in making a large change, and this scares you, please
418 make sure to first <a href="#newwork">discuss the change/gather
419 consensus</a> then ask about the best way to go about making
420 the change.</p>
421</div>
422
423<!-- _______________________________________________________________________ -->
424<div class="doc_subsection"><a name="attribution">Attribution of
425Changes</a></div>
426<div class="doc_text">
427 <p>We believe in correct attribution of contributions to
428 their contributors. However, we do not want the source code to be littered
Chris Lattnerfb5959f2007-12-29 19:56:08 +0000[diff] [blame]429 with random attributions "this code written by J Random Guy" (this is noisy
430 and distracting. In practice, the revision control system keeps a perfect
431 history of who change what, and the CREDITS.txt file describes higher-level
432 contributions.</p>
433
434 <p>Overall, please do not add contributor names to the source base.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]435</div>
436
437
438
439<!--=========================================================================-->
440<div class="doc_section">
441 <a name="clp">Copyright, License, and Patents</a>
442</div>
443<!--=========================================================================-->
444
445<div class="doc_text">
446 <p>This section addresses the issues of copyright, license and patents for
447 the LLVM project.
448 Currently, the University of Illinois is the LLVM copyright holder and the
449 terms of its license to LLVM users and developers is the
450 <a href="http://www.opensource.org/licenses/UoI-NCSA.php">University of
451 Illinois/NCSA Open Source License</a>.</p>
452
453<div class="doc_notes">
454 <p><b>NOTE: This section deals with legal matters but does not provide
455 legal advice. We are not lawyers, please seek legal counsel from an
456 attorney.</b></p>
457</div>
458</div>
459
460<!-- _______________________________________________________________________ -->
461<div class="doc_subsection"><a name="copyright">Copyright</a></div>
462<div class="doc_text">
463 <p>
464 <p>For consistency and ease of management, the project requires the
465 copyright for all LLVM software to be held by a single copyright holder:
466 the University of Illinois (UIUC).</p>
467
468 <p>
469 Although UIUC may eventually reassign the copyright of the software to another
Chris Lattner500d3942008-05-20 20:06:53 +0000[diff] [blame]470 entity (e.g. a dedicated non-profit "LLVM Organization")
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]471 the intent for the project is to always have a single entity hold the
472 copyrights to LLVM at any given time.</p>
473
474 <p>We believe that having a single copyright
475 holder is in the best interests of all developers and users as it greatly
476 reduces the managerial burden for any kind of administrative or technical
477 decisions about LLVM. The goal of the LLVM project is to always keep the code
478 open and <a href="#license">licensed under a very liberal license</a>.</p>
Chris Lattner500d3942008-05-20 20:06:53 +0000[diff] [blame]479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]480</div>
481
482<!-- _______________________________________________________________________ -->
483<div class="doc_subsection"><a name="license">License</a></div>
484<div class="doc_text">
485 <p>We intend to keep LLVM perpetually open source
486 and to use a liberal open source license. The current license is the
487 <a href="http://www.opensource.org/licenses/UoI-NCSA.php">
488 University of Illinois/NCSA Open Source License</a>, which boils
489 down to this:</p>
490 <ul>
491 <li>You can freely distribute LLVM.</li>
492 <li>You must retain the copyright notice if you redistribute LLVM.</li>
Chris Lattner500d3942008-05-20 20:06:53 +0000[diff] [blame]493 <li>Binaries derived from LLVM must reproduce the copyright notice (e.g.
494 in an included readme file).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]495 <li>You can't use our names to promote your LLVM derived products.</li>
496 <li>There's no warranty on LLVM at all.</li>
497 </ul>
498
499 <p>We believe this fosters the widest adoption of LLVM because it <b>allows
500 commercial products to be derived from LLVM</b> with few restrictions and
501 without a requirement for making any derived works also open source (i.e.
502 LLVM's license is not a "copyleft" license like the GPL). We suggest that you
503 read the <a href="http://www.opensource.org/licenses/UoI-NCSA.php">License</a>
504 if further clarification is needed.</p>
505
506 <p>Note that the LLVM Project does distribute llvm-gcc, <b>which is GPL.</b>
507 This means that anything "linked" into llvm-gcc must itself be compatible
508 with the GPL, and must be releasable under the terms of the GPL. This implies
509 that <b>any code linked into llvm-gcc and distributed to others may be subject
510 to the viral aspects of the GPL</b> (for example, a proprietary code generator
511 linked into llvm-gcc must be made available under the GPL). This is not a
512 problem for code already distributed under a more liberal license (like the
513 UIUC license), and does not affect code generated by llvm-gcc. It may be a
514 problem if you intend to base commercial development on llvm-gcc without
515 redistributing your source code.</p>
516
517 <p>We have no plans to change the license of LLVM. If you have questions
518 or comments about the license, please contact the <a
519 href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a>.</p>
520
521</div>
522
523<!-- _______________________________________________________________________ -->
524<div class="doc_subsection"><a name="patents">Patents</a></div>
525<div class="doc_text">
526
527<p>To the best of our knowledge, LLVM does not infringe on any patents (we have
528 actually removed code from LLVM in the past that was found to infringe).
529 Having code in LLVM that infringes on patents would violate an important
530 goal of the project by making it hard or impossible to reuse the code for
531 arbitrary purposes (including commercial use).</p>
532
533<p>When contributing code, we expect contributors to notify us of any potential
Chris Lattner31c01b12008-05-22 03:06:14 +0000[diff] [blame]534 for patent-related trouble with their changes. If you or your employer
535 own the rights to a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]536 patent and would like to contribute code to LLVM that relies on it, we
Chris Lattner31c01b12008-05-22 03:06:14 +0000[diff] [blame]537 require that
538 the copyright owner sign an agreement that allows any other user of LLVM to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]539 freely use your patent. Please contact the <a
540 href="mailto:llvm-oversight@cs.uiuc.edu">oversight group</a> for more
541 details.</p>
542</div>
543
544
545<!-- _______________________________________________________________________ -->
546<div class="doc_subsection"><a name="devagree">Developer Agreements</a></div>
547<div class="doc_text">
548 <p>With regards to the LLVM copyright and licensing, developers agree to
549 assign their copyrights to UIUC for any contribution made so that
550 the entire software base can be managed by a single copyright holder. This
551 implies that any contributions can be licensed under the license that the
552 project uses.</p>
Chris Lattner31c01b12008-05-22 03:06:14 +0000[diff] [blame]553
554 <p>When contributing code, you also affirm that you are legally entitled to
555 grant this copyright, personally or on behalf of your employer. If the code
556 belongs to some other entity, please raise this issue with the oversight
557 group before the code is committed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]558</div>
559
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