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4<head>
5 <title>LLVM Developer Policy</title>
6 <link rel="stylesheet" href="llvm.css" type="text/css">
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>
27 <li><a href="#patches">Patch Policies</a>
28 <ol>
29 <li><a href="#p_form">Patch Form</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]30 <li><a href="#p_submission">Patch Submission</a></li>
Reid Spencer0e598722007-02-14 17:20:59 +0000[diff] [blame]31 <li><a href="#p_aftersub">After Submission</a></li>
32 <li><a href="#p_aftercommit">After Commit</a></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]33 </ol></li>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]34 <li><a href="#candl">Copyright and License</a>
35 <ol>
36 <li><a href="#copyright">Copyright</a></li>
37 <li><a href="#license">License</a></li>
38 <li><a href="#devagree">Developer Agreements</a></li>
39 </ol></li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]40</ol>
41<div class="doc_author">Written by LLVM Oversight Team</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]42
43<!--=========================================================================-->
Reid Spencere7bd7d62007-02-14 17:24:04 +0000[diff] [blame]44<div class="doc_section"><a name="introduction">Introduction</a></div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]45<!--=========================================================================-->
46<div class="doc_text">
47 <p>This document contains the LLVM Developer Policy which defines the
Reid Spencerbed92532007-02-13 17:04:09 +0000[diff] [blame]48 project's policy towards developers and their contributions. The intent of
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]49 this policy is to eliminate mis-communication, rework, and confusion that
50 might arise from the distributed nature of LLVM's development. By stating
51 the policy in clear terms, we hope each developer can know ahead of time
52 what to expect when making LLVM contributions.</p>
Reid Spencer5b9a6092007-02-14 22:55:40 +0000[diff] [blame]53 <p>This policy is also designed to accomplish the following objectives:</p>
54 <ol>
55 <li>Attract both users and developers to the LLVM project.</li>
56 <li>Make life as simple and easy for contributors as possible.</li>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]57 <li>Keep the top of tree CVS/SVN trees as stable as possible.</li>
Reid Spencer5b9a6092007-02-14 22:55:40 +0000[diff] [blame]58 </ol>
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]59
60 <p>This policy is aimed at regular contributors to LLVM. People interested in
61 contributing one-off patches can do so in an informal way by sending them to
62 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">
63 llvm-commits mailing list</a> and engaging another developer to see it through
64 the process.</p>
65
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]66</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]67
68<!--=========================================================================-->
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]69<div class="doc_section"><a name="general">General Policies</a></div>
70<!--=========================================================================-->
71<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]72 <p>This section contains policies that pertain generally to regular LLVM
73 developers. We always welcome <a href="#patches">random patches</a> from
74 people who do not routinely contribute to LLVM, but expect more from regular
75 contributors to keep the system as efficient as possible for everyone.
76 Regular LLVM developers are expected to meet the following obligations in
77 order for LLVM to maintain a high standard of quality.<p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]78</div>
79
80<!-- _______________________________________________________________________ -->
81<div class="doc_subsection"> <a name="informed">Stay Informed</a> </div>
82<div class="doc_text">
83 <p>Developers should stay informed by reading at least the
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]84 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvmdev</a>
85 email list. If you are doing anything more than just casual work on LLVM,
86 it is suggested that you also subscribe to the
87 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>
88 list and pay attention to changes being made by others.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]89 <p>We recommend that active developers register an email account with
90 <a href="http://llvm.org/bugs/">LLVM Bugzilla</a> and preferably subscribe to
91 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs">llvm-bugs</a>
92 email list to keep track of bugs and enhancements occurring in LLVM.</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]93</div>
94
95<!-- _______________________________________________________________________ -->
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame^]96<div class="doc_subsection"> <a name="patches">Making a Patch</a></div>
97
98<div class="doc_text">
99
100<p>When making a patch for review, the goal is to make it as easy for the
101 reviewer to read it as possible. As such, we recommend that you:</p>
102 <ol>
103 <li>Make your patch against the CVS HEAD (main development trunk),
104 not a branch, and not an old version of LLVM. This makes it easy to
105 apply the patch.</li>
106
107 <li>Similarly, patches should be submitted soon after they are generated.
108 Old patches may not apply correctly if the underlying code changes between
109 the time the patch was created and the time it is applied.</li>
110
111 <li>Patches should be made with this command:
112 <pre>cvs diff -Ntdup -5</pre>
113 or with the utility <tt>utils/mkpatch</tt>. to make it easy to read the
114 diff.</li>
115
116 <li>Patches should not include differences in generated code such as the
117 code generated by <tt>flex</tt>, <tt>bison</tt> or <tt>tblgen</tt>. The
118 <tt>utils/mkpatch</tt> utility takes care of this for you.</li>
119
120 <li>Contributions must not knowingly infringe on any patents. To the best of
121 our knowledge, LLVM is free of any existing patent violations and it is our
122 intent to keep it that way.</li>
123 </ol>
124</div>
125
126<!-- _______________________________________________________________________ -->
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]127<div class="doc_subsection"> <a name="reviews">Code Reviews</a></div>
128<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]129 <p>LLVM has a code review policy. Code review is one way to increase the
130 quality of software. We generally follow these policies:</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]131 <ol>
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]132 <li>All developers are required to have significant changes reviewed
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]133 before they are committed to the repository.</li>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]134 <li>Code reviews are conducted by email, usually on the llvm-commits
135 list.</li>
136 <li>Code can be reviewed either before it is committed or after. We expect
137 major changes to be reviewed before being committed, but smaller
138 changes (or changes where the developer owns the component) can be
139 reviewed after commit.</li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]140 <li>The developer responsible for a code change is also responsible for
Chris Lattner1653fec2007-02-19 05:57:29 +0000[diff] [blame^]141 making all necessary review-related changes.</li>
142 <li>Code review can be an iterative process, which goes until all the patch
143 is ready to be committed.</li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]144 <li>Developers should participate in code reviews as both a reviewer and
145 a reviewee. We don't have a dedicated team of reviewers. If someone is
146 kind enough to review your code, you should return the favor for someone
147 else.</li>
148 </ol>
149</div>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]150
151<!-- _______________________________________________________________________ -->
152<div class="doc_subsection"> <a name="testcases">Test Cases</a></div>
153<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]154 <p>Developers are required to create test cases for any bugs fixed and any new
155 features added. The following policies apply:</p>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]156 <ol>
157 <li>All feature and regression test cases must be added to the
Reid Spencer80483bb2007-02-13 09:20:14 +0000[diff] [blame]158 <tt>llvm/test</tt> directory. The appropriate sub-directory should be
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]159 selected (see the <a href="TestingGuide.html">Testing Guide</a> for
Reid Spencer40602962007-02-13 20:57:57 +0000[diff] [blame]160 details).</li>
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]161 <li>Test cases should be written in
162 <a href="LangRef.html">LLVM assembly language</a> unless the
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]163 feature or regression being tested requires another language (e.g. the
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]164 bug being fixed or feature being implemented is in the llvm-gcc C++
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]165 front-end).</li>
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]166 <li>Test cases, especially for regressions, should be reduced as much as
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]167 possible, by <a href="CommandGuide/html/bugpoint.html">bugpoint</a> or
168 manually. It is unacceptable
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]169 to place an entire failing program into <tt>llvm/test</tt> as this creates
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]170 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]171 <li>More extensive test cases (applications, benchmarks, etc.) should be
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]172 added to the <tt>llvm-test</tt> test suite. This test suite is for
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]173 coverage: not features or regressions.</li>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]174 </ol>
175</div>
176
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]177<!-- _______________________________________________________________________ -->
Chris Lattner39582bd2007-02-19 05:47:13 +0000[diff] [blame]178<div class="doc_subsection"> <a name="quality">Quality</a></div>
179<div class="doc_text">
180 <p>The minimum quality standards that any change must satisfy before being
181 committed to the main development branch are:</p>
182 <ol>
183 <li>Code must adhere to the
184 <a href="CodingStandards.html">LLVM Coding Standards</a>.</li>
185 <li>Code must compile cleanly (no errors, no warnings) on at least one
186 platform.</li>
187 <li>Bug fixes and new features should <a href="#testcases">include a
188 testcase</a> so we know if the fix/feature ever regresses in the
189 future.</li>
190 <li>Code must pass the dejagnu (llvm/test) test suite.</li>
191 <li>The code must not cause regressions on a reasonable subset of llvm-test,
192 where "reasonable" depends on the contributor's judgement and the scope
193 of the change (more invasive changes require more testing). A reasonable
194 subset is "<tt>llvm-test/MultiSource/Benchmarks</tt>".</li>
195 </ol>
196 <p>Additionally, the committer is responsible for addressing any problems
197 found in the future that the change is responsible for. For example:</p>
198 <ul>
199 <li>The code should compile cleanly on all platforms.</li>
200 <li>The changes should not cause regressions in the <tt>llvm-test</tt>
201 suite including SPEC CINT2000, SPEC CFP2000, SPEC CINT2006, and
202 SPEC CFP2006.</li>
203 <li>The change set should not cause performance or correctness regressions
204 for the LLVM tools.</li>
205 <li>The changes should not cause performance or correctness regressions in
206 code compiled by LLVM on all applicable targets.</li>
207 <li>You are expected to address any <a href="http://llvm.org/bugs/">bugzilla
208 bugs</a> that result from your change.</li>
209 </ul>
210
211 <p>We prefer for this to be handled before submission but understand that it's
212 not possible to test all of this for every submission. Our nightly testing
213 infrastructure normally finds these problems. A good rule of thumb is to
214 check the nightly testers for regressions the day after your change.</p>
215
216 <p>Commits that violate these quality standards (e.g. are very broken) may
217 be reverted. This is necessary when the change blocks other developers from
218 making progress. The developer is welcome to re-commit the change after
219 the problem has been fixed.</p>
220</div>
221
222<!-- _______________________________________________________________________ -->
Chris Lattner1acdc952007-02-19 05:49:11 +0000[diff] [blame]223<div class="doc_subsection">
224 <a name="commitaccess">Obtaining Commit Access</a></div>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]225<div class="doc_text">
226
227<p>
228We grant commit access to contributors with a track record of submitting high
229quality patches. If you would like commit access, please send an email to the
230<a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM oversight group</a>.</p>
231
232<p>If you have recently been granted commit access, these policies apply:</p>
233<ol>
234 <li>You are granted <i>commit-after-approval</i> to all parts of LLVM.
235 To get approval, submit a <a href="#patches">patch</a> to
236 <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">
237 llvm-commits</a>. When approved you may commit it yourself.</li>
238 <li>You are allowed to commit patches without approval which you think are
239 obvious. This is clearly a subjective decision. We simply expect you to
240 use good judgement. Examples include: fixing build breakage, reverting
241 obviously broken patches, documentation/comment changes, any other minor
242 changes.</li>
243 <li>You are allowed to commit patches without approval to those portions
244 of LLVM that you have contributed or maintain (have been assigned
245 responsibility for), with the proviso that such commits must not break the
246 build. This is a "trust but verify" policy and commits of this nature are
247 reviewed after they are committed.</li>
248 <li>Multiple violations of these policies or a single egregious violation
249 may cause commit access to be revoked.</li>
250</ol>
251
252</div>
253
254<!-- _______________________________________________________________________ -->
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]255<div class="doc_subsection"> <a name="newwork">Making a Major Change</a></div>
256<div class="doc_text">
257 <p>When a developer begins a major new project with the aim of contributing
258 it back to LLVM, s/he should inform the community with an email to
259 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvm-dev</a>
260 email list, to the extent possible. The reason for this is to:
261 <ol>
262 <li>keep the community informed about future changes to LLVM, </li>
263 <li>avoid duplication of effort by having multiple parties working on the
264 same thing and not knowing about it, and</li>
265 <li>ensure that any technical issues around the proposed work are
266 discussed and resolved before any significant work is done.</li>
267 </ol>
268
269 <p>The design of LLVM is carefully controlled to ensure that all the pieces
270 fit together well and are as consistent as possible. If you plan to make a
271 major change to the way LLVM works or
272 a major new extension, it is a good idea to get consensus with the development
273 community before you start working on it.</p>
274
275</div>
276
277<!-- _______________________________________________________________________ -->
278<div class="doc_subsubsection"> <a name="incremental">Incremental Development</a>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]279</div>
280<div class="doc_text">
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]281 <p>Once the design of the new feature is finalized, the work itself should be
282 done as a series of incremental changes, not as a long-term development
283 branch. Long-term development branches have a number of drawbacks:</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]284
285 <ol>
286 <li>Branches must have mainline merged into them periodically. If the branch
287 development and mainline development occur in the same pieces of code,
288 resolving merge conflicts can take a lot of time.</li>
289 <li>Other people in the community tend to ignore work on branches.</li>
290 <li>Huge changes (produced when a branch is merged back onto mainline) are
291 extremely difficult to <a href="#reviews">code review</a>.</li>
292 <li>Branches are not routinely tested by our nightly tester
293 infrastructure.</li>
294 <li>Changes developed as monolithic large changes often don't work until the
295 entire set of changes is done. Breaking it down into a set of smaller
296 changes increases the odds that any of the work will be committed to the
297 main repository.</li>
298 </ol>
299
300 <p>
301 To address these problems, LLVM uses an incremental development style and we
302 require contributors to follow this practice when making a large/invasive
303 change. Some tips:</p>
304
305 <ul>
306 <li>Large/invasive changes usually have a number of secondary changes that
307 are required before the big change can be made (e.g. API cleanup, etc).
308 These sorts of changes can often be done before the major change is done,
309 independently of that work.</li>
310 <li>The remaining inter-related work should be decomposed into unrelated
311 sets of changes if possible. Once this is done, define the first increment
312 and get consensus on what the end goal of the change is.</li>
313 <li>Increments can be stand alone (e.g. to fix a bug), or part of a planned
314 series of increments towards some development goal.</li>
315 <li>Increments should be kept as small as possible. This simplifies your
316 work (into a logical progression), simplifies code review and reduces the
317 chance that you will get negative feedback on the change. Small increments
318 also facilitate the maintenance of a high quality code base.</li>
319 <li>Often, an independent precursor to a big change is to add a new API and
320 slowly migrate clients to use the new API. Each change to use the new
321 API is often "obvious" and can be committed without review. Once the
322 new API is in place and used, it is often easy to replace the underlying
323 implementation of the API.</li>
324 </ul>
325
326 <p>If you are interested in making a large change, and this scares you, please
327 make sure to first <a href="#newwork">discuss the change/gather
328 consensus</a> then feel free to ask about the best way to go about making
329 the change.</p>
330</div>
331
332<!-- _______________________________________________________________________ -->
Chris Lattnerc7d954e2007-02-19 05:43:04 +0000[diff] [blame]333<div class="doc_subsection"><a name="attribution">Attribution of
334Changes</a></div>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]335<div class="doc_text">
336 <p>We believe in correct attribution of contributions to
337 their contributors. However, we do not want the source code to be littered
338 with random attributions (this is noisy/distracting and revision control
339 keeps a perfect history of this anyway). As such, we follow these rules:</p>
340 <ol>
341 <li>Developers who originate new files in LLVM should place their name at
342 the top of the file per the
343 <a href="CodingStandards.html#scf_commenting">Coding Standards</a>.</li>
344 <li>There should be only one name at the top of the file and it should be
345 the person who created the file.</li>
346 <li>Placing your name in the file does not imply <a
347 href="#candl">copyright</a>: it is only used to attribute the file to
348 its original author.</li>
349 <li>Developers should be aware that after some time has passed, the name at
350 the top of a file may become meaningless as maintenance/ownership of files
351 changes. Revision control keeps an accurate history of contributions.</li>
352 <li>Developers should maintain their entry in the
353 <a href="http://llvm.org/cvsweb/cvsweb.cgi/llvm/CREDITS.TXT?rev=HEAD&amp;content-type=text/x-cvsweb-markup">CREDITS.txt</a>
354 file to summarize their contributions.</li>
355 <li>Commit comments should contain correct attribution of the person who
356 submitted the patch if that person is not the committer (i.e. when a
357 developer with commit privileges commits a patch for someone else).</li>
358 </ol>
359</div>
360
361
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]362
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]363<!--=========================================================================-->
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]364<div class="doc_section"><a name="candl">Copyright and License</a></div>
365<!--=========================================================================-->
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]366
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]367<div class="doc_text">
368 <p>We address here the issues of copyright and license for the LLVM project.
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]369 The object of the copyright and license is the LLVM source code and
370 documentation.
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]371 Currently, the University of Illinois is the LLVM copyright holder and the
372 terms of its license to LLVM users and developers is the
373 <a href="http://www.opensource.org/licenses/UoI-NCSA.php">University of
374 Illinois/NCSA Open Source License</a>.
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]375
376<div class="doc_notes">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]377 <p><b>NOTE: This section deals with legal matters but does not provide
378 official legal advice. We are not lawyers, please seek legal counsel from an
379 attorney.</b></p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]380</div>
381
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]382</div>
383
384<!-- _______________________________________________________________________ -->
385<div class="doc_subsection"><a name="copyright">Copyright</a></div>
386<div class="doc_text">
387 <p>
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]388 <p>For consistency and ease of management, the project requires the
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]389 copyright for all LLVM software to be held by a single copyright holder:
390 the University of Illinois (UIUC).</p>
391
392 <p>
393 Although UIUC may eventually reassign the copyright of the software to another
394 entity (e.g. a dedicated non-profit "LLVM Organization", or something)
395 the intent for the project is to always have a single entity hold the
396 copyrights to LLVM at any given time.</p>
397
398 <p>We believe that having a single copyright
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]399 holder is in the best interests of all developers and users as it greatly
400 reduces the managerial burden for any kind of administrative or technical
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]401 decisions about LLVM. The goal of the LLVM project is to always keep the code
402 open and <a href="#license">licensed under a very liberal license</a>.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]403</div>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]404
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]405<!-- _______________________________________________________________________ -->
406<div class="doc_subsection"><a name="license">License</a></div>
407<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]408 <p>We intend to keep LLVM perpetually open source
409 and to use a liberal open source license. The current license is the
Reid Spencer01f56be2007-02-14 16:21:10 +0000[diff] [blame]410 <a href="http://www.opensource.org/licenses/UoI-NCSA.php">
411 University of Illinois/NCSA Open Source License</a>, which boils
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]412 down to this:</p>
413 <ul>
414 <li>You can freely distribute LLVM.</li>
415 <li>You must retain the copyright notice if you redistribute LLVM.</li>
416 <li>Binaries derived from LLVM must reproduce the copyright notice.</li>
417 <li>You can't use our names to promote your LLVM derived products.</li>
418 <li>There's no warranty on LLVM at all.</li>
419 </ul>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]420
421 <p>We believe this fosters the widest adoption of LLVM because it <b>allows
422 commercial products to be derived from LLVM</b> with few restrictions and
Reid Spencer5b9a6092007-02-14 22:55:40 +0000[diff] [blame]423 without a requirement for making any derived works also open source (i.e.
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]424 LLVM's license is not a "copyleft" license like the GPL). We suggest that you
425 read the <a href="http://www.opensource.org/licenses/UoI-NCSA.php">License</a>
Reid Spencer853418d2007-02-14 22:58:39 +0000[diff] [blame]426 if further clarification is needed.</p>
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]427
428 <p>Note that the LLVM Project does distribute some code that includes GPL
429 software (notably, llvm-gcc which is based on the GCC GPL source base).
430 This means that anything "linked" into to llvm-gcc must itself be compatible
431 with the GPL, and must be releasable under the terms of the GPL. This implies
432 that you <b>any code linked into llvm-gcc and distributed may be subject to
433 the viral aspects of the GPL</b>. This is not a problem for the main LLVM
434 distribution (which is already licensed under a more liberal license), but may
435 be a problem if you intend to do commercial development without redistributing
436 your source code.</p>
437
438 <p>We have no plans to change the license of LLVM. If you have questions
439 or comments about the license, please contact the <a
440 href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a>.</p>
441
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]442</div>
443<!-- _______________________________________________________________________ -->
444<div class="doc_subsection"><a name="devagree">Developer Agreements</a></div>
445<div class="doc_text">
Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]446 <p>With regards to the LLVM copyright and licensing, developers agree to
447 assign their copyrights to UIUC for any contribution made so that
448 the entire software base can be managed by a single copyright holder. This
449 implies that any contributions can be licensed under the license that the
Chris Lattner1acdc952007-02-19 05:49:11 +0000[diff] [blame]450 project uses.</p>
Reid Spencer78bade22007-02-14 07:22:19 +0000[diff] [blame]451</div>
452
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]453<!-- *********************************************************************** -->
454<hr>
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Chris Lattner450f40a2007-02-19 03:50:31 +0000[diff] [blame]460 Written by: the
Reid Spencer3eedbd32007-02-14 07:57:48 +0000[diff] [blame]461 <a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a><br>
Reid Spencer8d0ac692007-02-13 09:06:01 +0000[diff] [blame]462 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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