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5 <title>LLVM Developer Policy</title>
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7</head>
8<body>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]9
10<div class="doc_title">LLVM Developer Policy</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]11<ol>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]12 <li><a href="#introduction">Introduction</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]13 <li><a href="#general">General Policies</a>
14 <ol>
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame]15 <li><a href="#informed">Stay Informed</a></li>
16 <li><a href="#patches">Making a Patch</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]17 <li><a href="#reviews">Code Reviews</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]18 <li><a href="#testcases">Test Cases</a></li>
Chris Lattner1acdc952007-02-19 05:49:11 +0000[diff] [blame]19 <li><a href="#quality">Quality</a></li>
20 <li><a href="#commitaccess">Obtaining Commit Access</a></li>
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]21 <li><a href="#newwork">Making a Major Change</a>
22 <ol>
23 <li><a href="#incremental">Incremental Development</a></li>
24 </ol></li>
25 <li><a href="#attribution">Attribution of Changes</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]26 </ol></li>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]27 <li><a href="#candl">Copyright and License</a>
28 <ol>
29 <li><a href="#copyright">Copyright</a></li>
30 <li><a href="#license">License</a></li>
31 <li><a href="#devagree">Developer Agreements</a></li>
32 </ol></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]33</ol>
34<div class="doc_author">Written by LLVM Oversight Team</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]35
36<!--=========================================================================-->
Reid Spencere7bd7d62007-02-14 17:24:04 +0000[diff] [blame]37<div class="doc_section"><a name="introduction">Introduction</a></div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]38<!--=========================================================================-->
39<div class="doc_text">
40 <p>This document contains the LLVM Developer Policy which defines the
Reid Spencerbed92532007-02-13 17:04:09 +0000[diff] [blame]41 project's policy towards developers and their contributions. The intent of
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]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>
Reid Spencer5b9a6092007-02-14 22:55:40 +0000[diff] [blame]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>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]50 <li>Keep the top of tree CVS/SVN trees as stable as possible.</li>
Reid Spencer5b9a6092007-02-14 22:55:40 +0000[diff] [blame]51 </ol>
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]52
53 <p>This policy is aimed at regular 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
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]59</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]60
61<!--=========================================================================-->
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]62<div class="doc_section"><a name="general">General Policies</a></div>
63<!--=========================================================================-->
64<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]65 <p>This section contains policies that pertain generally to regular LLVM
66 developers. We always welcome <a href="#patches">random patches</a> from
67 people who do not routinely contribute to LLVM, but expect more from regular
68 contributors to keep the system as efficient as possible for everyone.
69 Regular LLVM developers are expected to meet the following obligations in
70 order for LLVM to maintain a high standard of quality.<p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]71</div>
72
73<!-- _______________________________________________________________________ -->
74<div class="doc_subsection"> <a name="informed">Stay Informed</a> </div>
75<div class="doc_text">
76 <p>Developers should stay informed by reading at least the
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]77 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvmdev</a>
78 email list. If you are doing anything more than just casual work on LLVM,
79 it is suggested that you also subscribe to the
80 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>
81 list and pay attention to changes being made by others.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]82 <p>We recommend that active developers register an email account with
83 <a href="http://llvm.org/bugs/">LLVM Bugzilla</a> and preferably subscribe to
84 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs">llvm-bugs</a>
85 email list to keep track of bugs and enhancements occurring in LLVM.</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]86</div>
87
88<!-- _______________________________________________________________________ -->
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame]89<div class="doc_subsection"> <a name="patches">Making a Patch</a></div>
90
91<div class="doc_text">
92
93<p>When making a patch for review, the goal is to make it as easy for the
94 reviewer to read it as possible. As such, we recommend that you:</p>
95 <ol>
96 <li>Make your patch against the CVS HEAD (main development trunk),
97 not a branch, and not an old version of LLVM. This makes it easy to
98 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>cvs diff -Ntdup -5</pre>
106 or with the utility <tt>utils/mkpatch</tt>. to make 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 <li>Contributions must not knowingly infringe on any patents. To the best of
114 our knowledge, LLVM is free of any existing patent violations and it is our
115 intent to keep it that way.</li>
116 </ol>
117</div>
118
119<!-- _______________________________________________________________________ -->
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]120<div class="doc_subsection"> <a name="reviews">Code Reviews</a></div>
121<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]122 <p>LLVM has a code review policy. Code review is one way to increase the
123 quality of software. We generally follow these policies:</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]124 <ol>
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]125 <li>All developers are required to have significant changes reviewed
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]126 before they are committed to the repository.</li>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]127 <li>Code reviews are conducted by email, usually on the llvm-commits
128 list.</li>
129 <li>Code can be reviewed either before it is committed or after. We expect
130 major changes to be reviewed before being committed, but smaller
131 changes (or changes where the developer owns the component) can be
132 reviewed after commit.</li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]133 <li>The developer responsible for a code change is also responsible for
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame]134 making all necessary review-related changes.</li>
135 <li>Code review can be an iterative process, which goes until all the patch
136 is ready to be committed.</li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]137 <li>Developers should participate in code reviews as both a reviewer and
138 a reviewee. We don't have a dedicated team of reviewers. If someone is
139 kind enough to review your code, you should return the favor for someone
140 else.</li>
141 </ol>
142</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]143
144<!-- _______________________________________________________________________ -->
145<div class="doc_subsection"> <a name="testcases">Test Cases</a></div>
146<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]147 <p>Developers are required to create test cases for any bugs fixed and any new
148 features added. The following policies apply:</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]149 <ol>
150 <li>All feature and regression test cases must be added to the
Reid Spencer80483bb2007-02-13 09:20:14 +0000[diff] [blame]151 <tt>llvm/test</tt> directory. The appropriate sub-directory should be
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]152 selected (see the <a href="TestingGuide.html">Testing Guide</a> for
Reid Spencer40602962007-02-13 20:57:57 +0000[diff] [blame]153 details).</li>
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]154 <li>Test cases should be written in
155 <a href="LangRef.html">LLVM assembly language</a> unless the
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]156 feature or regression being tested requires another language (e.g. the
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]157 bug being fixed or feature being implemented is in the llvm-gcc C++
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]158 front-end).</li>
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]159 <li>Test cases, especially for regressions, should be reduced as much as
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]160 possible, by <a href="CommandGuide/html/bugpoint.html">bugpoint</a> or
161 manually. It is unacceptable
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]162 to place an entire failing program into <tt>llvm/test</tt> as this creates
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]163 a <i>time-to-test</i> burden on all developers. Please keep them short.</li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]164 <li>More extensive test cases (applications, benchmarks, etc.) should be
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]165 added to the <tt>llvm-test</tt> test suite. This test suite is for
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]166 coverage: not features or regressions.</li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]167 </ol>
168</div>
169
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]170<!-- _______________________________________________________________________ -->
Chris Lattner39582bd2007-02-19 05:47:13 +0000[diff] [blame]171<div class="doc_subsection"> <a name="quality">Quality</a></div>
172<div class="doc_text">
173 <p>The minimum quality standards that any change must satisfy before being
174 committed to the main development branch are:</p>
175 <ol>
176 <li>Code must adhere to the
177 <a href="CodingStandards.html">LLVM Coding Standards</a>.</li>
178 <li>Code must compile cleanly (no errors, no warnings) on at least one
179 platform.</li>
180 <li>Bug fixes and new features should <a href="#testcases">include a
181 testcase</a> so we know if the fix/feature ever regresses in the
182 future.</li>
183 <li>Code must pass the dejagnu (llvm/test) test suite.</li>
184 <li>The code must not cause regressions on a reasonable subset of llvm-test,
185 where "reasonable" depends on the contributor's judgement and the scope
186 of the change (more invasive changes require more testing). A reasonable
187 subset is "<tt>llvm-test/MultiSource/Benchmarks</tt>".</li>
188 </ol>
189 <p>Additionally, the committer is responsible for addressing any problems
190 found in the future that the change is responsible for. For example:</p>
191 <ul>
192 <li>The code should compile cleanly on all platforms.</li>
193 <li>The changes should not cause regressions in the <tt>llvm-test</tt>
194 suite including SPEC CINT2000, SPEC CFP2000, SPEC CINT2006, and
195 SPEC CFP2006.</li>
196 <li>The change set should not cause performance or correctness regressions
197 for the LLVM tools.</li>
198 <li>The changes should not cause performance or correctness regressions in
199 code compiled by LLVM on all applicable targets.</li>
200 <li>You are expected to address any <a href="http://llvm.org/bugs/">bugzilla
201 bugs</a> that result from your change.</li>
202 </ul>
203
204 <p>We prefer for this to be handled before submission but understand that it's
205 not possible to test all of this for every submission. Our nightly testing
206 infrastructure normally finds these problems. A good rule of thumb is to
207 check the nightly testers for regressions the day after your change.</p>
208
209 <p>Commits that violate these quality standards (e.g. are very broken) may
210 be reverted. This is necessary when the change blocks other developers from
211 making progress. The developer is welcome to re-commit the change after
212 the problem has been fixed.</p>
213</div>
214
215<!-- _______________________________________________________________________ -->
Chris Lattner1acdc952007-02-19 05:49:11 +0000[diff] [blame]216<div class="doc_subsection">
217 <a name="commitaccess">Obtaining Commit Access</a></div>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]218<div class="doc_text">
219
220<p>
221We grant commit access to contributors with a track record of submitting high
222quality patches. If you would like commit access, please send an email to the
223<a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM oversight group</a>.</p>
224
225<p>If you have recently been granted commit access, these policies apply:</p>
226<ol>
227 <li>You are granted <i>commit-after-approval</i> to all parts of LLVM.
228 To get approval, submit a <a href="#patches">patch</a> to
229 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">
230 llvm-commits</a>. When approved you may commit it yourself.</li>
231 <li>You are allowed to commit patches without approval which you think are
232 obvious. This is clearly a subjective decision. We simply expect you to
233 use good judgement. Examples include: fixing build breakage, reverting
234 obviously broken patches, documentation/comment changes, any other minor
235 changes.</li>
236 <li>You are allowed to commit patches without approval to those portions
237 of LLVM that you have contributed or maintain (have been assigned
238 responsibility for), with the proviso that such commits must not break the
239 build. This is a "trust but verify" policy and commits of this nature are
240 reviewed after they are committed.</li>
241 <li>Multiple violations of these policies or a single egregious violation
242 may cause commit access to be revoked.</li>
243</ol>
244
245</div>
246
247<!-- _______________________________________________________________________ -->
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]248<div class="doc_subsection"> <a name="newwork">Making a Major Change</a></div>
249<div class="doc_text">
250 <p>When a developer begins a major new project with the aim of contributing
251 it back to LLVM, s/he should inform the community with an email to
252 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvm-dev</a>
253 email list, to the extent possible. The reason for this is to:
254 <ol>
255 <li>keep the community informed about future changes to LLVM, </li>
256 <li>avoid duplication of effort by having multiple parties working on the
257 same thing and not knowing about it, and</li>
258 <li>ensure that any technical issues around the proposed work are
259 discussed and resolved before any significant work is done.</li>
260 </ol>
261
262 <p>The design of LLVM is carefully controlled to ensure that all the pieces
263 fit together well and are as consistent as possible. If you plan to make a
264 major change to the way LLVM works or
265 a major new extension, it is a good idea to get consensus with the development
266 community before you start working on it.</p>
267
268</div>
269
270<!-- _______________________________________________________________________ -->
271<div class="doc_subsubsection"> <a name="incremental">Incremental Development</a>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]272</div>
273<div class="doc_text">
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]274 <p>Once the design of the new feature is finalized, the work itself should be
275 done as a series of incremental changes, not as a long-term development
276 branch. Long-term development branches have a number of drawbacks:</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]277
278 <ol>
279 <li>Branches must have mainline merged into them periodically. If the branch
280 development and mainline development occur in the same pieces of code,
281 resolving merge conflicts can take a lot of time.</li>
282 <li>Other people in the community tend to ignore work on branches.</li>
283 <li>Huge changes (produced when a branch is merged back onto mainline) are
284 extremely difficult to <a href="#reviews">code review</a>.</li>
285 <li>Branches are not routinely tested by our nightly tester
286 infrastructure.</li>
287 <li>Changes developed as monolithic large changes often don't work until the
288 entire set of changes is done. Breaking it down into a set of smaller
289 changes increases the odds that any of the work will be committed to the
290 main repository.</li>
291 </ol>
292
293 <p>
294 To address these problems, LLVM uses an incremental development style and we
295 require contributors to follow this practice when making a large/invasive
296 change. Some tips:</p>
297
298 <ul>
299 <li>Large/invasive changes usually have a number of secondary changes that
300 are required before the big change can be made (e.g. API cleanup, etc).
301 These sorts of changes can often be done before the major change is done,
302 independently of that work.</li>
303 <li>The remaining inter-related work should be decomposed into unrelated
304 sets of changes if possible. Once this is done, define the first increment
305 and get consensus on what the end goal of the change is.</li>
Chris Lattner8bb16ff2007-02-19 05:59:30 +0000[diff] [blame^]306
307 <li>Each change in the set can be stand alone (e.g. to fix a bug), or part
308 of a planned series of changes that works towards the development goal.</li>
309
310 <li>Each change should be kept as small as possible. This simplifies your
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]311 work (into a logical progression), simplifies code review and reduces the
312 chance that you will get negative feedback on the change. Small increments
313 also facilitate the maintenance of a high quality code base.</li>
Chris Lattner8bb16ff2007-02-19 05:59:30 +0000[diff] [blame^]314
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]315 <li>Often, an independent precursor to a big change is to add a new API and
316 slowly migrate clients to use the new API. Each change to use the new
317 API is often "obvious" and can be committed without review. Once the
318 new API is in place and used, it is often easy to replace the underlying
319 implementation of the API.</li>
320 </ul>
321
322 <p>If you are interested in making a large change, and this scares you, please
323 make sure to first <a href="#newwork">discuss the change/gather
324 consensus</a> then feel free to ask about the best way to go about making
325 the change.</p>
326</div>
327
328<!-- _______________________________________________________________________ -->
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]329<div class="doc_subsection"><a name="attribution">Attribution of
330Changes</a></div>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]331<div class="doc_text">
332 <p>We believe in correct attribution of contributions to
333 their contributors. However, we do not want the source code to be littered
334 with random attributions (this is noisy/distracting and revision control
335 keeps a perfect history of this anyway). As such, we follow these rules:</p>
336 <ol>
337 <li>Developers who originate new files in LLVM should place their name at
338 the top of the file per the
339 <a href="CodingStandards.html#scf_commenting">Coding Standards</a>.</li>
340 <li>There should be only one name at the top of the file and it should be
341 the person who created the file.</li>
342 <li>Placing your name in the file does not imply <a
343 href="#candl">copyright</a>: it is only used to attribute the file to
344 its original author.</li>
345 <li>Developers should be aware that after some time has passed, the name at
346 the top of a file may become meaningless as maintenance/ownership of files
347 changes. Revision control keeps an accurate history of contributions.</li>
348 <li>Developers should maintain their entry in the
349 <a href="http://llvm.org/cvsweb/cvsweb.cgi/llvm/CREDITS.TXT?rev=HEAD&amp;content-type=text/x-cvsweb-markup">CREDITS.txt</a>
350 file to summarize their contributions.</li>
351 <li>Commit comments should contain correct attribution of the person who
352 submitted the patch if that person is not the committer (i.e. when a
353 developer with commit privileges commits a patch for someone else).</li>
354 </ol>
355</div>
356
357
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]358
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]359<!--=========================================================================-->
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]360<div class="doc_section"><a name="candl">Copyright and License</a></div>
361<!--=========================================================================-->
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]362
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]363<div class="doc_text">
364 <p>We address here the issues of copyright and license for the LLVM project.
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]365 The object of the copyright and license is the LLVM source code and
366 documentation.
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]367 Currently, the University of Illinois is the LLVM copyright holder and the
368 terms of its license to LLVM users and developers is the
369 <a href="http://www.opensource.org/licenses/UoI-NCSA.php">University of
370 Illinois/NCSA Open Source License</a>.
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]371
372<div class="doc_notes">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]373 <p><b>NOTE: This section deals with legal matters but does not provide
374 official legal advice. We are not lawyers, please seek legal counsel from an
375 attorney.</b></p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]376</div>
377
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]378</div>
379
380<!-- _______________________________________________________________________ -->
381<div class="doc_subsection"><a name="copyright">Copyright</a></div>
382<div class="doc_text">
383 <p>
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]384 <p>For consistency and ease of management, the project requires the
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]385 copyright for all LLVM software to be held by a single copyright holder:
386 the University of Illinois (UIUC).</p>
387
388 <p>
389 Although UIUC may eventually reassign the copyright of the software to another
390 entity (e.g. a dedicated non-profit "LLVM Organization", or something)
391 the intent for the project is to always have a single entity hold the
392 copyrights to LLVM at any given time.</p>
393
394 <p>We believe that having a single copyright
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]395 holder is in the best interests of all developers and users as it greatly
396 reduces the managerial burden for any kind of administrative or technical
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]397 decisions about LLVM. The goal of the LLVM project is to always keep the code
398 open and <a href="#license">licensed under a very liberal license</a>.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]399</div>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]400
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]401<!-- _______________________________________________________________________ -->
402<div class="doc_subsection"><a name="license">License</a></div>
403<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]404 <p>We intend to keep LLVM perpetually open source
405 and to use a liberal open source license. The current license is the
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]406 <a href="http://www.opensource.org/licenses/UoI-NCSA.php">
407 University of Illinois/NCSA Open Source License</a>, which boils
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]408 down to this:</p>
409 <ul>
410 <li>You can freely distribute LLVM.</li>
411 <li>You must retain the copyright notice if you redistribute LLVM.</li>
412 <li>Binaries derived from LLVM must reproduce the copyright notice.</li>
413 <li>You can't use our names to promote your LLVM derived products.</li>
414 <li>There's no warranty on LLVM at all.</li>
415 </ul>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]416
417 <p>We believe this fosters the widest adoption of LLVM because it <b>allows
418 commercial products to be derived from LLVM</b> with few restrictions and
Reid Spencer5b9a6092007-02-14 22:55:40 +0000[diff] [blame]419 without a requirement for making any derived works also open source (i.e.
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]420 LLVM's license is not a "copyleft" license like the GPL). We suggest that you
421 read the <a href="http://www.opensource.org/licenses/UoI-NCSA.php">License</a>
Reid Spencer853418d2007-02-14 22:58:39 +0000[diff] [blame]422 if further clarification is needed.</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]423
424 <p>Note that the LLVM Project does distribute some code that includes GPL
425 software (notably, llvm-gcc which is based on the GCC GPL source base).
426 This means that anything "linked" into to llvm-gcc must itself be compatible
427 with the GPL, and must be releasable under the terms of the GPL. This implies
428 that you <b>any code linked into llvm-gcc and distributed may be subject to
429 the viral aspects of the GPL</b>. This is not a problem for the main LLVM
430 distribution (which is already licensed under a more liberal license), but may
431 be a problem if you intend to do commercial development without redistributing
432 your source code.</p>
433
434 <p>We have no plans to change the license of LLVM. If you have questions
435 or comments about the license, please contact the <a
436 href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a>.</p>
437
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]438</div>
439<!-- _______________________________________________________________________ -->
440<div class="doc_subsection"><a name="devagree">Developer Agreements</a></div>
441<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]442 <p>With regards to the LLVM copyright and licensing, developers agree to
443 assign their copyrights to UIUC for any contribution made so that
444 the entire software base can be managed by a single copyright holder. This
445 implies that any contributions can be licensed under the license that the
Chris Lattner1acdc952007-02-19 05:49:11 +0000[diff] [blame]446 project uses.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]447</div>
448
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]449<!-- *********************************************************************** -->
450<hr>
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Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]456 Written by: the
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]457 <a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a><br>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]458 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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