<div class="doc_title">LLVM Developer Policy</div>
<ol>
<li><a href="#introduction">Introduction</a></li>
- <li><a href="#general">General Policies</a>
+ <li><a href="#policies">Developer Policies</a>
<ol>
- <li><a href="#informed">Stay Informed</a> </li>
- <li><a href="#newwork">Starting New Work</a></li>
+ <li><a href="#informed">Stay Informed</a></li>
+ <li><a href="#patches">Making a Patch</a></li>
<li><a href="#reviews">Code Reviews</a></li>
- <li><a href="#quality">Quality</a></li>
+ <li><a href="#owners">Code Owners</a></li>
<li><a href="#testcases">Test Cases</a></li>
- <li><a href="#c_new">Obtaining Commit Access</a></li>
+ <li><a href="#quality">Quality</a></li>
+ <li><a href="#commitaccess">Obtaining Commit Access</a></li>
+ <li><a href="#newwork">Making a Major Change</a></li>
<li><a href="#incremental">Incremental Development</a></li>
- <li><a href="#attribution">Attribution</a></li>
+ <li><a href="#attribution">Attribution of Changes</a></li>
</ol></li>
- <li><a href="#patches">Patch Policies</a>
- <ol>
- <li><a href="#p_form">Patch Form</a></li>
- <li><a href="#p_submission">Patch Submission</a></li>
- <li><a href="#p_aftersub">After Submission</a></li>
- <li><a href="#p_aftercommit">After Commit</a></li>
- </ol></li>
- <li><a href="#candl">Copyright and License</a>
+ <li><a href="#clp">Copyright, License, and Patents</a>
<ol>
<li><a href="#copyright">Copyright</a></li>
<li><a href="#license">License</a></li>
+ <li><a href="#patents">Patents</a></li>
<li><a href="#devagree">Developer Agreements</a></li>
</ol></li>
- <li><a href="#terms">Terminology</a></li>
</ol>
-<div class="doc_author">Written by LLVM Oversight Team</div>
+<div class="doc_author">Written by the LLVM Oversight Team</div>
<!--=========================================================================-->
<div class="doc_section"><a name="introduction">Introduction</a></div>
<ol>
<li>Attract both users and developers to the LLVM project.</li>
<li>Make life as simple and easy for contributors as possible.</li>
- <li>Keep the top of tree CVS/SVN trees as stable as possible.</li>
+ <li>Keep the top of Subversion trees as stable as possible.</li>
</ol>
+
+ <p>This policy is aimed at frequent contributors to LLVM. People interested in
+ contributing one-off patches can do so in an informal way by sending them to
+ the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">
+ llvm-commits mailing list</a> and engaging another developer to see it through
+ the process.</p>
+
</div>
<!--=========================================================================-->
-<div class="doc_section"><a name="general">General Policies</a></div>
+<div class="doc_section"><a name="policies">Developer Policies</a></div>
<!--=========================================================================-->
<div class="doc_text">
- <p>This section contains policies that pertain generally to regular LLVM
- developers. We always welcome <a href="#patches">random patches</a> from
- people who do not routinely contribute to LLVM, but expect more from regular
- contributors to keep the system as efficient as possible for everyone.
- Regular LLVM developers are expected to meet the following obligations in
+ <p>This section contains policies that pertain to frequent LLVM
+ developers. We always welcome <a href="#patches">one-off patches</a> from
+ people who do not routinely contribute to LLVM, but we expect more from
+ frequent contributors to keep the system as efficient as possible for
+ everyone.
+ Frequent LLVM contributors are expected to meet the following requirements in
order for LLVM to maintain a high standard of quality.<p>
</div>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"> <a name="newwork">Starting New Work</a></div>
+<div class="doc_subsection"> <a name="patches">Making a Patch</a></div>
+
<div class="doc_text">
- <p>When a developer begins a major new project with the aim of contributing
- it back to LLVM, s/he should inform the community with an email to
- the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvm-dev</a>
- email list, to the extent possible. The reason for this is to:
+
+<p>When making a patch for review, the goal is to make it as easy for the
+ reviewer to read it as possible. As such, we recommend that you:</p>
<ol>
- <li>keep the community informed about future changes to LLVM, </li>
- <li>avoid duplication of effort by having multiple parties working on the
- same thing and not knowing about it, and</li>
- <li>ensure that any technical issues around the proposed work are
- discussed and resolved before any significant work is done.</li>
+ <li>Make your patch against the Subversion trunk, not a branch, and not an
+ old version of LLVM. This makes it easy to apply the patch.</li>
+
+ <li>Similarly, patches should be submitted soon after they are generated.
+ Old patches may not apply correctly if the underlying code changes between
+ the time the patch was created and the time it is applied.</li>
+
+ <li>Patches should be made with this command:
+ <pre>svn diff -x -u</pre>
+ or with the utility <tt>utils/mkpatch</tt>, which makes it easy to read the
+ diff.</li>
+
+ <li>Patches should not include differences in generated code such as the
+ code generated by <tt>flex</tt>, <tt>bison</tt> or <tt>tblgen</tt>. The
+ <tt>utils/mkpatch</tt> utility takes care of this for you.</li>
+
</ol>
- <p>The design of LLVM is carefully controlled to ensure that all the pieces
- fit together well and are as consistent as possible. If you plan to make a
- major change to the way LLVM works or
- a major new extension, it is a good idea to get consensus with the development
- community before you start working on it.</p>
+
+ <p>When sending a patch to a mailing list, it is a good idea to send it as an
+ <em>attachment</em> to the message, not embedded into the text of the
+ message. This ensures that your mailer will not mangle the patch when it
+ sends it (e.g. by making whitespace changes or by wrapping lines).</p>
</div>
<!-- _______________________________________________________________________ -->
changes (or changes where the developer owns the component) can be
reviewed after commit.</li>
<li>The developer responsible for a code change is also responsible for
- making all necessary review-related changes.</li>
- <li>Developers should participate in code reviews as both a reviewer and
- a reviewee. We don't have a dedicated team of reviewers. If someone is
- kind enough to review your code, you should return the favor for someone
- else.</li>
+ making all necessary review-related changes.</li>
+ <li>Code review can be an iterative process, which continues until the patch
+ is ready to be committed.</li>
+ </ol>
+
+ <p>Developers should participate in code reviews as both reviewers and
+ reviewees. If someone is kind enough to review your code, you should
+ return the favor for someone else. Note that anyone is welcome to review
+ and give feedback on a patch, but only people with Subversion write access
+ can approve it.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsection"> <a name="owners">Code Owners</a></div>
+<div class="doc_text">
+
+ <p>The LLVM Project relies on two features of its process to maintain rapid
+ development in addition to the high quality of its source base: the
+ combination of code review plus post-commit review for trusted maintainers.
+ Having both is a great way for the project to take advantage of the fact
+ that most people do the right thing most of the time, and only commit
+ patches without pre-commit review when they are confident they are
+ right.</p>
+
+ <p>The trick to this is that the project has to guarantee that all patches
+ that are committed are reviewed after they go in: you don't want everyone
+ to assume someone else will review it, allowing the patch to go unreviewed.
+ To solve this problem, we have a notion of an 'owner' for a piece of the
+ code. The sole responsibility of a code owner is to ensure that a commit
+ to their area of the code is appropriately reviewed, either by themself or
+ by someone else. The current code owners are:</p>
+
+ <ol>
+ <li><b>Anton Korobeynikov</b>: Exception handling, debug information, and
+ Windows codegen.</li>
+ <li><b>Duncan Sands</b>: llvm-gcc 4.2.</li>
+ <li><b>Evan Cheng</b>: Code generator and all targets.</li>
+ <li><b>Chris Lattner</b>: Everything else.</li>
+ </ol>
+
+ <p>Note that code ownership is completely different than reviewers: anyone can
+ review a piece of code, and we welcome code review from anyone who is
+ interested. Code owners are the "last line of defense" to guarantee that
+ all patches that are committed are actually reviewed.</p>
+
+ <p>Being a code owner is a somewhat unglamorous position, but it is incredibly
+ important for the ongoing success of the project. Because people get busy,
+ interests change, and unexpected things happen, code ownership is purely
+ opt-in, and anyone can choose to resign their "title" at any time. For now,
+ we do not have an official policy on how one gets elected to be a code
+ owner.
+ </p>
+
+</div>
+
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsection"> <a name="testcases">Test Cases</a></div>
+<div class="doc_text">
+ <p>Developers are required to create test cases for any bugs fixed and any new
+ features added. Some tips for getting your testcase approved:</p>
+ <ol>
+ <li>All feature and regression test cases are added to the
+ <tt>llvm/test</tt> directory. The appropriate sub-directory should be
+ selected (see the <a href="TestingGuide.html">Testing Guide</a> for
+ details).</li>
+ <li>Test cases should be written in
+ <a href="LangRef.html">LLVM assembly language</a> unless the
+ feature or regression being tested requires another language (e.g. the
+ bug being fixed or feature being implemented is in the llvm-gcc C++
+ front-end, in which case it must be written in C++).</li>
+ <li>Test cases, especially for regressions, should be reduced as much as
+ possible, by <a href="Bugpoint.html">bugpoint</a> or
+ manually. It is unacceptable
+ to place an entire failing program into <tt>llvm/test</tt> as this creates
+ a <i>time-to-test</i> burden on all developers. Please keep them short.</li>
</ol>
+
+ <p>Note that llvm/test is designed for regression and small feature tests
+ only. More extensive test cases (e.g., entire applications, benchmarks,
+ etc) should be added to the <tt>llvm-test</tt> test suite. The llvm-test
+ suite is for coverage (correctness, performance, etc) testing, not feature
+ or regression testing.</p>
</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsection"> <a name="quality">Quality</a></div>
<div class="doc_text">
<a href="CodingStandards.html">LLVM Coding Standards</a>.</li>
<li>Code must compile cleanly (no errors, no warnings) on at least one
platform.</li>
- <li>Code must pass the deja gnu (llvm/test) test suite.</li>
+ <li>Bug fixes and new features should <a href="#testcases">include a
+ testcase</a> so we know if the fix/feature ever regresses in the
+ future.</li>
+ <li>Code must pass the dejagnu (<tt>llvm/test</tt>) test suite.</li>
<li>The code must not cause regressions on a reasonable subset of llvm-test,
where "reasonable" depends on the contributor's judgement and the scope
of the change (more invasive changes require more testing). A reasonable
subset is "<tt>llvm-test/MultiSource/Benchmarks</tt>".</li>
</ol>
<p>Additionally, the committer is responsible for addressing any problems
- found that the change is responsible for. For example:</p>
+ found in the future that the change is responsible for. For example:</p>
<ul>
- <li>The code should compile cleanly on all platforms.</li>
- <li>The changes should not cause regressions in the <tt>llvm-test</tt>
- suite including SPEC CINT2000, SPEC CFP2000, SPEC CINT2006, and
- SPEC CFP2006.</li>
+ <li>The code should compile cleanly on all supported platforms.</li>
+ <li>The changes should not cause any correctness regressions in the
+ <tt>llvm-test</tt> suite and must not cause any major performance
+ regressions.</li>
<li>The change set should not cause performance or correctness regressions
for the LLVM tools.</li>
<li>The changes should not cause performance or correctness regressions in
bugs</a> that result from your change.</li>
</ul>
- <p>We prefer for this to be handled before submission but understand that it's
- not possible to test all of this for every submission. Our nightly testing
+ <p>We prefer for this to be handled before submission but understand that it
+ isn't possible to test all of this for every submission. Our nightly
+ testing
infrastructure normally finds these problems. A good rule of thumb is to
check the nightly testers for regressions the day after your change.</p>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"> <a name="testcases">Test Cases</a></div>
-<div class="doc_text">
- <p>Developers are required to create test cases for any bugs fixed and any new
- features added. The following policies apply:</p>
- <ol>
- <li>All feature and regression test cases must be added to the
- <tt>llvm/test</tt> directory. The appropriate sub-directory should be
- selected (see the <a href="TestingGuide.html">Testing Guide</a> for
- details).</li>
- <li>Test cases should be written in
- <a href="LangRef.html">LLVM assembly language</a> unless the
- feature or regression being tested requires another language (e.g. the
- bug being fixed or feature being implemented is in the llvm-gcc C++
- front-end).</li>
- <li>Test cases, especially for regressions, should be reduced as much as
- possible, by <a href="CommandGuide/html/bugpoint.html">bugpoint</a> or
- manually. It is unacceptable
- to place an entire failing program into <tt>llvm/test</tt> as this creates
- a <i>time-to-test</i> burden on all developers. Please keep them short.</li>
- <li>More extensive test cases (applications, benchmarks, etc.) should be
- added to the <tt>llvm-test</tt> test suite. This test suite is for
- coverage: not features or regressions.</li>
- </ol>
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"> <a name="c_new">Obtaining Commit Access</a></div>
+<div class="doc_subsection">
+ <a name="commitaccess">Obtaining Commit Access</a></div>
<div class="doc_text">
<p>
We grant commit access to contributors with a track record of submitting high
-quality patches. If you would like commit access, please send an email to the
-<a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM oversight group</a>.</p>
+quality patches. If you would like commit access, please send an email to
+<a href="mailto:sabre@nondot.org">Chris</a> with the following information:</p>
+
+<ol>
+ <li>The user name you want to commit with, e.g. "sabre".</li>
+ <li>The full name and email address you want message to llvm-commits to come
+ from, e.g. "Chris Lattner <sabre@nondot.org>".</li>
+ <li>A "password hash" of the password you want to use, e.g. "2ACR96qjUqsyM".
+ Note that you don't ever tell us what your password is, you just give it
+ to us in an encrypted form. To get this, run "htpasswd" (a utility that
+ comes with apache) in crypt mode (often enabled with "-d"), or find a web
+ page that will do it for you.</li>
+</ol>
+
+<p>Once you've been granted commit access, you should be able to check out an
+ LLVM tree with an SVN URL of "https://username@llvm.org/..." instead of the
+ normal anonymous URL of "http://llvm.org/...". The first time you commit
+ you'll have to type in your password. Note that you may get a warning from
+ SVN about an untrusted key, you can ignore this. To verify that your commit
+ access works, please do a test commit (e.g. change a comment or add a blank
+ line). Your first commit to a repository may require the autogenerated email
+ to be approved by a mailing list. This is normal, and will be done when
+ the mailing list owner has time.</p>
<p>If you have recently been granted commit access, these policies apply:</p>
+
<ol>
<li>You are granted <i>commit-after-approval</i> to all parts of LLVM.
To get approval, submit a <a href="#patches">patch</a> to
<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">
llvm-commits</a>. When approved you may commit it yourself.</li>
<li>You are allowed to commit patches without approval which you think are
- obvious. This is clearly a subjective decision. We simply expect you to
- use good judgement. Examples include: fixing build breakage, reverting
+ obvious. This is clearly a subjective decision — we simply expect you
+ to use good judgement. Examples include: fixing build breakage, reverting
obviously broken patches, documentation/comment changes, any other minor
changes.</li>
<li>You are allowed to commit patches without approval to those portions
- of LLVM that you have contributed or maintain (have been assigned
+ of LLVM that you have contributed or maintain (i.e., have been assigned
responsibility for), with the proviso that such commits must not break the
build. This is a "trust but verify" policy and commits of this nature are
reviewed after they are committed.</li>
<li>Multiple violations of these policies or a single egregious violation
may cause commit access to be revoked.</li>
</ol>
+
+<p>In any case, your changes are still subject to <a href="#reviews">code
+review</a> (either before or after they are committed, depending on the nature
+of the change). You are encouraged to review other peoples' patches as well,
+but you aren't required to.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsection"> <a name="newwork">Making a Major Change</a></div>
+<div class="doc_text">
+ <p>When a developer begins a major new project with the aim of contributing
+ it back to LLVM, s/he should inform the community with an email to
+ the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvmdev</a>
+ email list, to the extent possible. The reason for this is to:
+ <ol>
+ <li>keep the community informed about future changes to LLVM, </li>
+ <li>avoid duplication of effort by preventing multiple parties working on
+ the same thing and not knowing about it, and</li>
+ <li>ensure that any technical issues around the proposed work are
+ discussed and resolved before any significant work is done.</li>
+ </ol>
+
+ <p>The design of LLVM is carefully controlled to ensure that all the pieces
+ fit together well and are as consistent as possible. If you plan to make a
+ major change to the way LLVM works or want to add a major new extension, it
+ is a good idea to get consensus with the development
+ community before you start working on it.</p>
+ <p>Once the design of the new feature is finalized, the work itself should be
+ done as a series of <a href="#incremental">incremental changes</a>, not as
+ a long-term development branch.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsection"> <a name="incremental">Incremental Development</a>
</div>
<div class="doc_text">
- <p>When making a large change to LLVM, we use a incremental style of
- development instead of having long-term development branches. Long-term
- development branches have a number of drawbacks:</p>
+ <p>In the LLVM project, we do all significant changes as a series of
+ incremental patches. We have a strong dislike for huge changes or
+ long-term development branches. Long-term development branches have a
+ number of drawbacks:</p>
<ol>
<li>Branches must have mainline merged into them periodically. If the branch
<li>The remaining inter-related work should be decomposed into unrelated
sets of changes if possible. Once this is done, define the first increment
and get consensus on what the end goal of the change is.</li>
- <li>Increments can be stand alone (e.g. to fix a bug), or part of a planned
- series of increments towards some development goal.</li>
- <li>Increments should be kept as small as possible. This simplifies your
+
+ <li>Each change in the set can be stand alone (e.g. to fix a bug), or part
+ of a planned series of changes that works towards the development goal.</li>
+
+ <li>Each change should be kept as small as possible. This simplifies your
work (into a logical progression), simplifies code review and reduces the
chance that you will get negative feedback on the change. Small increments
also facilitate the maintenance of a high quality code base.</li>
+
<li>Often, an independent precursor to a big change is to add a new API and
slowly migrate clients to use the new API. Each change to use the new
API is often "obvious" and can be committed without review. Once the
- new API is in place and used, it is often easy to replace the underlying
- implementation of the API.</li>
+ new API is in place and used, it is much easier to replace the
+ underlying implementation of the API. This implementation change is
+ logically separate from the API change.</li>
</ul>
<p>If you are interested in making a large change, and this scares you, please
make sure to first <a href="#newwork">discuss the change/gather
- consensus</a> then feel free to ask about the best way to go about making
+ consensus</a> then ask about the best way to go about making
the change.</p>
</div>
<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="attribution">Attribution</a></div>
+<div class="doc_subsection"><a name="attribution">Attribution of
+Changes</a></div>
<div class="doc_text">
<p>We believe in correct attribution of contributions to
their contributors. However, we do not want the source code to be littered
- with random attributions (this is noisy/distracting and revision control
- keeps a perfect history of this anyway). As such, we follow these rules:</p>
- <ol>
- <li>Developers who originate new files in LLVM should place their name at
- the top of the file per the
- <a href="CodingStandards.html#scf_commenting">Coding Standards</a>.</li>
- <li>There should be only one name at the top of the file and it should be
- the person who created the file.</li>
- <li>Placing your name in the file does not imply <a
- href="#candl">copyright</a>: it is only used to attribute the file to
- its original author.</li>
- <li>Developers should be aware that after some time has passed, the name at
- the top of a file may become meaningless as maintenance/ownership of files
- changes. Revision control keeps an accurate history of contributions.</li>
- <li>Developers should maintain their entry in the
- <a href="http://llvm.org/cvsweb/cvsweb.cgi/llvm/CREDITS.TXT?rev=HEAD&content-type=text/x-cvsweb-markup">CREDITS.txt</a>
- file to summarize their contributions.</li>
- <li>Commit comments should contain correct attribution of the person who
- submitted the patch if that person is not the committer (i.e. when a
- developer with commit privileges commits a patch for someone else).</li>
- </ol>
-</div>
+ with random attributions "this code written by J Random Guy" (this is noisy
+ and distracting. In practice, the revision control system keeps a perfect
+ history of who change what, and the CREDITS.txt file describes higher-level
+ contributions.</p>
-
-<!--=========================================================================-->
-<div class="doc_section"><a name="patches">Patch Policies</a></div>
-<!--=========================================================================-->
-
-<div class="doc_text">
- <p>This section describes policies that apply to developers who regularly
- contribute code to LLVM. As usual, we often accept small patches and
- contributions that do not follow this policy. In this case, one of the
- regular contributors has to get the code in shape.</p>
+ <p>Overall, please do not add contributor names to the source base.</p>
</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"> <a name="p_form">Patch Form</a></div>
-<div class="doc_text">
- <p>When submitting a patch, developers must follow these rules:</p>
- <ol>
- <li>Patches must be made against the CVS HEAD (main development trunk),
- not a branch.</li>
- <li>Patches should be made with this command:
- <pre>cvs diff -Ntdup -5</pre>
- or with the utility <tt>utils/mkpatch</tt>.</li>
- <li>Patches should not include differences in generated code such as the
- code generated by <tt>flex</tt>, <tt>bison</tt> or <tt>tblgen</tt>. The
- <tt>utils/mkpatch</tt> utility takes care of this for you.</li>
- <li>Contributions must not knowingly infringe on any patents. To the best of
- our knowledge, LLVM is free of any existing patent violations and it is our
- intent to keep it that way.</li>
- </ol>
-</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"> <a name="p_submission">Patch Submission</a></div>
-<div class="doc_text">
- <p>When a patch is ready to be submitted, these policies apply:</p>
- <ol>
- <li>Patches should be submitted immediately after they are generated. Stale
- patches may not apply correctly if the underlying code changes between the
- time the patch was created and the time it is applied.</li>
- <li>Patches should be submitted by e-mail to the
- <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">
- llvm-commits</a> list.</li>
- </ol>
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"> <a name="p_aftersub">After Submission</a></div>
-<div class="doc_text">
- <p>After a patch has been submitted, these policies apply:</p>
- <ol>
- <li>The patch is subject to review by anyone on the
- <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>
- email list.</li>
- <li>Changes recommended by a reviewer should be incorporated into your
- patch or you should explain why the reviewer is incorrect.
- <li>Changes to the patch must be re-submitted to the
- <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>
- email list.</li>
- <li>This process iterates until all review issues have been addressed.</li>
- </ol>
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"> <a name="p_aftercommit">After Commit</a></div>
-<div class="doc_text">
- <p>After a patch has been committed, these policies apply:</p>
- <ol>
- <li>The patch is subject to further review by anyone on the llvm-commits
- email list.</li>
- <li>The patch submitter is responsible for all aspects of the patch per
- the <a href="quality">quality policy</a> above.</li>
- <li>If the patch is discovered to not meet the
- <a href="quality">quality policy</a> standards within a reasonable time
- frame (24 hours), it may be subject to reversal.</li>
- </ol>
-</div>
<!--=========================================================================-->
-<div class="doc_section"><a name="candl">Copyright and License</a></div>
+<div class="doc_section">
+ <a name="clp">Copyright, License, and Patents</a>
+</div>
<!--=========================================================================-->
<div class="doc_text">
- <p>We address here the issues of copyright and license for the LLVM project.
- The object of the copyright and license is the LLVM source code and
- documentation.
+ <p>This section addresses the issues of copyright, license and patents for
+ the LLVM project.
Currently, the University of Illinois is the LLVM copyright holder and the
terms of its license to LLVM users and developers is the
<a href="http://www.opensource.org/licenses/UoI-NCSA.php">University of
- Illinois/NCSA Open Source License</a>.
+ Illinois/NCSA Open Source License</a>.</p>
<div class="doc_notes">
<p><b>NOTE: This section deals with legal matters but does not provide
- official legal advice. We are not lawyers, please seek legal counsel from an
+ legal advice. We are not lawyers, please seek legal counsel from an
attorney.</b></p>
</div>
-
</div>
<!-- _______________________________________________________________________ -->
read the <a href="http://www.opensource.org/licenses/UoI-NCSA.php">License</a>
if further clarification is needed.</p>
- <p>Note that the LLVM Project does distribute some code that includes GPL
- software (notably, llvm-gcc which is based on the GCC GPL source base).
- This means that anything "linked" into to llvm-gcc must itself be compatible
+ <p>Note that the LLVM Project does distribute llvm-gcc, <b>which is GPL.</b>
+ This means that anything "linked" into llvm-gcc must itself be compatible
with the GPL, and must be releasable under the terms of the GPL. This implies
- that you <b>any code linked into llvm-gcc and distributed may be subject to
- the viral aspects of the GPL</b>. This is not a problem for the main LLVM
- distribution (which is already licensed under a more liberal license), but may
- be a problem if you intend to do commercial development without redistributing
- your source code.</p>
+ that <b>any code linked into llvm-gcc and distributed to others may be subject
+ to the viral aspects of the GPL</b> (for example, a proprietary code generator
+ linked into llvm-gcc must be made available under the GPL). This is not a
+ problem for code already distributed under a more liberal license (like the
+ UIUC license), and does not affect code generated by llvm-gcc. It may be a
+ problem if you intend to base commercial development on llvm-gcc without
+ redistributing your source code.</p>
<p>We have no plans to change the license of LLVM. If you have questions
or comments about the license, please contact the <a
href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a>.</p>
</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsection"><a name="patents">Patents</a></div>
+<div class="doc_text">
+
+<p>To the best of our knowledge, LLVM does not infringe on any patents (we have
+ actually removed code from LLVM in the past that was found to infringe).
+ Having code in LLVM that infringes on patents would violate an important
+ goal of the project by making it hard or impossible to reuse the code for
+ arbitrary purposes (including commercial use).</p>
+
+<p>When contributing code, we expect contributors to notify us of any potential
+ for patent-related trouble with their changes. If you own the rights to a
+ patent and would like to contribute code to LLVM that relies on it, we
+ require that you sign an agreement that allows any other user of LLVM to
+ freely use your patent. Please contact the <a
+ href="mailto:llvm-oversight@cs.uiuc.edu">oversight group</a> for more
+ details.</p>
+</div>
+
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsection"><a name="devagree">Developer Agreements</a></div>
<div class="doc_text">
assign their copyrights to UIUC for any contribution made so that
the entire software base can be managed by a single copyright holder. This
implies that any contributions can be licensed under the license that the
- project uses.</li>
- </ul>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_section"><a name="terms">Terminology</a></div>
-<!--=========================================================================-->
-<div class="doc_text">
- <p>So that the policies defined in this document are clear, we define some
- terms here.</p>
- <dl>
- <dt><a name="t_change">Change</a></dt>
- <dd>Any modification to LLVM including documentation, tests, build system,
- etc. either in <a href="#t_patch">patch</a> or
- <a href="#t_commit">commit</a> form.</dd>
- <dt><a name="t_commit">Commit</a><dt>
- <dd>A <a href="t_change">change</a> submitted directly to LLVM software
- repository via the <tt>cvs commit</tt> command.</dd>
- <dt><a name="t_developer">Developer</a></dt>
- <dd>Anyone who submits a <a href="#t_change">change</a> to LLVM.</dd>
- <dt><a name="t_inrement">Increment</a></dt>
- <dd>A <a href="#t_change">change</a> or set of changes, whether by
- <a href="#t_patch">patch</a> or <a href="#t_commit">commit</a>, that are
- related by a single common purpose. Increments are atomic as they
- leave LLVM in a stable state (both compiling and working properly).</dd>
- <dt><a name="t_patch">Patch</a></dt>
- <dd>A <a href="#t_change">change</a> submitted by email in patch (diff)
- format generated by the <tt>cvs diff</tt> command.</dd>
- </dl>
+ project uses.</p>
</div>
<!-- *********************************************************************** -->
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- Written by: the
+ Written by the
<a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a><br>
<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
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