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<title>LLVM Developer Policy</title>
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<div class="doc_title">LLVM Developer Policy</div>
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<ol>
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<li><a href="#introduction">Introduction</a></li>
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<li><a href="#policies">Developer Policies</a>
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<ol>
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<li><a href="#informed">Stay Informed</a></li>
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<li><a href="#patches">Making a Patch</a></li>
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<li><a href="#reviews">Code Reviews</a></li>
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<li><a href="#owners">Code Owners</a></li>
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<li><a href="#testcases">Test Cases</a></li>
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<li><a href="#quality">Quality</a></li>
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<li><a href="#commitaccess">Obtaining Commit Access</a></li>
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<li><a href="#newwork">Making a Major Change</a></li>
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<li><a href="#incremental">Incremental Development</a></li>
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<li><a href="#attribution">Attribution of Changes</a></li>
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</ol></li>
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<li><a href="#clp">Copyright, License, and Patents</a>
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<ol>
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<li><a href="#copyright">Copyright</a></li>
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<li><a href="#license">License</a></li>
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<li><a href="#patents">Patents</a></li>
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<li><a href="#devagree">Developer Agreements</a></li>
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</ol></li>
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</ol>
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<div class="doc_author">Written by the LLVM Oversight Team</div>
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<!--=========================================================================-->
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<div class="doc_section"><a name="introduction">Introduction</a></div>
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<!--=========================================================================-->
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<div class="doc_text">
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<p>This document contains the LLVM Developer Policy which defines the project's
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policy towards developers and their contributions. The intent of this policy
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is to eliminate miscommunication, rework, and confusion that might arise from
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the distributed nature of LLVM's development. By stating the policy in clear
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terms, we hope each developer can know ahead of time what to expect when
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making LLVM contributions.</p>
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<p>This policy is also designed to accomplish the following objectives:</p>
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<ol>
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<li>Attract both users and developers to the LLVM project.</li>
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<li>Make life as simple and easy for contributors as possible.</li>
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<li>Keep the top of Subversion trees as stable as possible.</li>
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</ol>
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<p>This policy is aimed at frequent contributors to LLVM. People interested in
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contributing one-off patches can do so in an informal way by sending them to
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the
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<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits
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mailing list</a> and engaging another developer to see it through the
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process.</p>
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</div>
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<!--=========================================================================-->
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<div class="doc_section"><a name="policies">Developer Policies</a></div>
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<!--=========================================================================-->
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<div class="doc_text">
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<p>This section contains policies that pertain to frequent LLVM developers. We
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always welcome <a href="#patches">one-off patches</a> from people who do not
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routinely contribute to LLVM, but we expect more from frequent contributors
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to keep the system as efficient as possible for everyone. Frequent LLVM
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contributors are expected to meet the following requirements in order for
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LLVM to maintain a high standard of quality.<p>
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</div>
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<!-- _______________________________________________________________________ -->
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<div class="doc_subsection"> <a name="informed">Stay Informed</a> </div>
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<div class="doc_text">
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<p>Developers should stay informed by reading at least the
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<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">llvmdev</a> email
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list. If you are doing anything more than just casual work on LLVM, it is
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suggested that you also subscribe to the
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<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>
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list and pay attention to changes being made by others.</p>
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<p>We recommend that active developers register an email account with
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<a href="http://llvm.org/bugs/">LLVM Bugzilla</a> and preferably subscribe to
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the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs">llvm-bugs</a>
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email list to keep track of bugs and enhancements occurring in LLVM.</p>
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</div>
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2007-02-19 05:57:29 +00:00
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<!-- _______________________________________________________________________ -->
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<div class="doc_subsection"> <a name="patches">Making a Patch</a></div>
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<div class="doc_text">
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<p>When making a patch for review, the goal is to make it as easy for the
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reviewer to read it as possible. As such, we recommend that you:</p>
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<ol>
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<li>Make your patch against the Subversion trunk, not a branch, and not an old
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version of LLVM. This makes it easy to apply the patch. For information
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on how to check out SVN trunk, please see the <a
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href="GettingStarted.html#checkout">Getting Started Guide</a>.</li>
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<li>Similarly, patches should be submitted soon after they are generated. Old
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patches may not apply correctly if the underlying code changes between the
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time the patch was created and the time it is applied.</li>
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2010-08-04 16:07:22 +00:00
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<li>Patches should be made with <tt>svn diff</tt>, or similar. If you use
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a different tool, make sure it uses the <tt>diff -u</tt> format and
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that it doesn't contain clutter which makes it hard to read.</li>
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2010-08-04 16:07:22 +00:00
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<li>If you are modifying generated files, such as the top-level
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<tt>configure</tt> script, please separate out those changes into
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a separate patch from the rest of your changes.</li>
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</ol>
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2008-06-26 22:58:37 +00:00
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2009-04-05 12:37:44 +00:00
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<p>When sending a patch to a mailing list, it is a good idea to send it as an
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<em>attachment</em> to the message, not embedded into the text of the
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message. This ensures that your mailer will not mangle the patch when it
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sends it (e.g. by making whitespace changes or by wrapping lines).</p>
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<p><em>For Thunderbird users:</em> Before submitting a patch, please open
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<em>Preferences → Advanced → General → Config Editor</em>,
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find the key <tt>mail.content_disposition_type</tt>, and set its value to
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<tt>1</tt>. Without this setting, Thunderbird sends your attachment using
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<tt>Content-Disposition: inline</tt> rather than <tt>Content-Disposition:
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attachment</tt>. Apple Mail gamely displays such a file inline, making it
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difficult to work with for reviewers using that program.</p>
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</div>
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2007-02-13 09:06:01 +00:00
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<!-- _______________________________________________________________________ -->
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<div class="doc_subsection"> <a name="reviews">Code Reviews</a></div>
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<div class="doc_text">
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<p>LLVM has a code review policy. Code review is one way to increase the quality
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of software. We generally follow these policies:</p>
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<ol>
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<li>All developers are required to have significant changes reviewed before
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they are committed to the repository.</li>
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<li>Code reviews are conducted by email, usually on the llvm-commits
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list.</li>
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<li>Code can be reviewed either before it is committed or after. We expect
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major changes to be reviewed before being committed, but smaller changes
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(or changes where the developer owns the component) can be reviewed after
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commit.</li>
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<li>The developer responsible for a code change is also responsible for making
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all necessary review-related changes.</li>
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<li>Code review can be an iterative process, which continues until the patch
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is ready to be committed.</li>
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</ol>
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<p>Developers should participate in code reviews as both reviewers and
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reviewees. If someone is kind enough to review your code, you should return
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the favor for someone else. Note that anyone is welcome to review and give
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feedback on a patch, but only people with Subversion write access can approve
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it.</p>
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</div>
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2007-02-19 05:47:13 +00:00
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2007-12-03 19:00:47 +00:00
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<!-- _______________________________________________________________________ -->
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<div class="doc_subsection"> <a name="owners">Code Owners</a></div>
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<div class="doc_text">
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2009-04-05 12:37:44 +00:00
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<p>The LLVM Project relies on two features of its process to maintain rapid
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development in addition to the high quality of its source base: the
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combination of code review plus post-commit review for trusted maintainers.
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Having both is a great way for the project to take advantage of the fact that
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most people do the right thing most of the time, and only commit patches
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without pre-commit review when they are confident they are right.</p>
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2009-04-05 12:37:44 +00:00
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<p>The trick to this is that the project has to guarantee that all patches that
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are committed are reviewed after they go in: you don't want everyone to
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assume someone else will review it, allowing the patch to go unreviewed. To
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solve this problem, we have a notion of an 'owner' for a piece of the code.
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The sole responsibility of a code owner is to ensure that a commit to their
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area of the code is appropriately reviewed, either by themself or by someone
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else. The current code owners are:</p>
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<ol>
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<li><b>Evan Cheng</b>: Code generator and all targets.</li>
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2009-09-16 05:36:07 +00:00
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<li><b>Doug Gregor</b>: Clang Basic, Lex, Parse, and Sema Libraries.</li>
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2009-09-16 05:37:13 +00:00
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<li><b>Anton Korobeynikov</b>: Exception handling, debug information, and
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Windows codegen.</li>
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2009-09-16 05:42:12 +00:00
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<li><b>Ted Kremenek</b>: Clang Static Analyzer.</li>
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2009-09-16 05:36:54 +00:00
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<li><b>Chris Lattner</b>: Everything not covered by someone else.</li>
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<li><b>Duncan Sands</b>: llvm-gcc 4.2.</li>
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</ol>
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<p>Note that code ownership is completely different than reviewers: anyone can
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review a piece of code, and we welcome code review from anyone who is
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interested. Code owners are the "last line of defense" to guarantee that all
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patches that are committed are actually reviewed.</p>
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<p>Being a code owner is a somewhat unglamorous position, but it is incredibly
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important for the ongoing success of the project. Because people get busy,
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interests change, and unexpected things happen, code ownership is purely
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opt-in, and anyone can choose to resign their "title" at any time. For now,
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we do not have an official policy on how one gets elected to be a code
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owner.</p>
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</div>
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<!-- _______________________________________________________________________ -->
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<div class="doc_subsection"> <a name="testcases">Test Cases</a></div>
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<div class="doc_text">
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<p>Developers are required to create test cases for any bugs fixed and any new
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features added. Some tips for getting your testcase approved:</p>
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<ol>
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<li>All feature and regression test cases are added to the
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<tt>llvm/test</tt> directory. The appropriate sub-directory should be
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selected (see the <a href="TestingGuide.html">Testing Guide</a> for
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details).</li>
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<li>Test cases should be written in <a href="LangRef.html">LLVM assembly
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language</a> unless the feature or regression being tested requires
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another language (e.g. the bug being fixed or feature being implemented is
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in the llvm-gcc C++ front-end, in which case it must be written in
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C++).</li>
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<li>Test cases, especially for regressions, should be reduced as much as
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possible, by <a href="Bugpoint.html">bugpoint</a> or manually. It is
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unacceptable to place an entire failing program into <tt>llvm/test</tt> as
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this creates a <i>time-to-test</i> burden on all developers. Please keep
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them short.</li>
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</ol>
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2007-02-19 06:57:16 +00:00
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2009-04-05 12:37:44 +00:00
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<p>Note that llvm/test is designed for regression and small feature tests
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only. More extensive test cases (e.g., entire applications, benchmarks, etc)
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should be added to the <tt>llvm-test</tt> test suite. The llvm-test suite is
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for coverage (correctness, performance, etc) testing, not feature or
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regression testing.</p>
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2007-02-19 05:47:13 +00:00
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</div>
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2007-02-13 09:06:01 +00:00
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<!-- _______________________________________________________________________ -->
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<div class="doc_subsection"> <a name="quality">Quality</a></div>
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<div class="doc_text">
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2009-04-05 12:37:44 +00:00
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<p>The minimum quality standards that any change must satisfy before being
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committed to the main development branch are:</p>
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<ol>
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<li>Code must adhere to the <a href="CodingStandards.html">LLVM Coding
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Standards</a>.</li>
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<li>Code must compile cleanly (no errors, no warnings) on at least one
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platform.</li>
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<li>Bug fixes and new features should <a href="#testcases">include a
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testcase</a> so we know if the fix/feature ever regresses in the
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|
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future.</li>
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|
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<li>Code must pass the dejagnu (<tt>llvm/test</tt>) test suite.</li>
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<li>The code must not cause regressions on a reasonable subset of llvm-test,
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where "reasonable" depends on the contributor's judgement and the scope of
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the change (more invasive changes require more testing). A reasonable
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subset might be something like
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"<tt>llvm-test/MultiSource/Benchmarks</tt>".</li>
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</ol>
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|
|
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|
|
|
|
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<p>Additionally, the committer is responsible for addressing any problems found
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|
in the future that the change is responsible for. For example:</p>
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|
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<ul>
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<li>The code should compile cleanly on all supported platforms.</li>
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<li>The changes should not cause any correctness regressions in the
|
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|
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<tt>llvm-test</tt> suite and must not cause any major performance
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|
regressions.</li>
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<li>The change set should not cause performance or correctness regressions for
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the LLVM tools.</li>
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<li>The changes should not cause performance or correctness regressions in
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code compiled by LLVM on all applicable targets.</li>
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|
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<li>You are expected to address any <a href="http://llvm.org/bugs/">bugzilla
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|
bugs</a> that result from your change.</li>
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</ul>
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2007-02-19 03:50:31 +00:00
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2009-04-05 12:37:44 +00:00
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<p>We prefer for this to be handled before submission but understand that it
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2009-08-01 19:25:25 +00:00
|
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isn't possible to test all of this for every submission. Our build bots and
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|
nightly testing infrastructure normally finds these problems. A good rule of
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|
thumb is to check the nightly testers for regressions the day after your
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|
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|
change. Build bots will directly email you if a group of commits that
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|
included yours caused a failure. You are expected to check the build bot
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|
messages to see if they are your fault and, if so, fix the breakage.</p>
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2009-04-05 12:37:44 +00:00
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<p>Commits that violate these quality standards (e.g. are very broken) may be
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|
reverted. This is necessary when the change blocks other developers from
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|
making progress. The developer is welcome to re-commit the change after the
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problem has been fixed.</p>
|
2007-02-13 09:06:01 +00:00
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</div>
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|
2007-02-19 03:50:31 +00:00
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|
<!-- _______________________________________________________________________ -->
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2007-02-19 05:49:11 +00:00
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<div class="doc_subsection">
|
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|
|
|
<a name="commitaccess">Obtaining Commit Access</a></div>
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2007-02-19 03:50:31 +00:00
|
|
|
<div class="doc_text">
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|
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|
|
2009-04-05 12:37:44 +00:00
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<p>We grant commit access to contributors with a track record of submitting high
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|
quality patches. If you would like commit access, please send an email to
|
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|
<a href="mailto:sabre@nondot.org">Chris</a> with the following
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|
information:</p>
|
2007-12-03 00:36:20 +00:00
|
|
|
|
|
|
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|
<ol>
|
2009-04-05 12:37:44 +00:00
|
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<li>The user name you want to commit with, e.g. "hacker".</li>
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|
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|
2007-12-03 00:36:20 +00:00
|
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<li>The full name and email address you want message to llvm-commits to come
|
2009-04-05 12:37:44 +00:00
|
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|
from, e.g. "J. Random Hacker <hacker@yoyodyne.com>".</li>
|
|
|
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|
2007-12-03 00:36:20 +00:00
|
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|
<li>A "password hash" of the password you want to use, e.g. "2ACR96qjUqsyM".
|
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|
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|
Note that you don't ever tell us what your password is, you just give it
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|
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
|
|
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|
LLVM tree with an SVN URL of "https://username@llvm.org/..." instead of the
|
|
|
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|
normal anonymous URL of "http://llvm.org/...". The first time you commit
|
|
|
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|
you'll have to type in your password. Note that you may get a warning from
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|
|
SVN about an untrusted key, you can ignore this. To verify that your commit
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|
|
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|
access works, please do a test commit (e.g. change a comment or add a blank
|
|
|
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|
line). Your first commit to a repository may require the autogenerated email
|
|
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|
to be approved by a mailing list. This is normal, and will be done when
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|
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|
the mailing list owner has time.</p>
|
2007-02-19 03:50:31 +00:00
|
|
|
|
|
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|
<p>If you have recently been granted commit access, these policies apply:</p>
|
2007-12-03 00:36:20 +00:00
|
|
|
|
2007-02-19 03:50:31 +00:00
|
|
|
<ol>
|
2009-04-05 12:37:44 +00:00
|
|
|
<li>You are granted <i>commit-after-approval</i> to all parts of LLVM. To get
|
|
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|
|
approval, submit a <a href="#patches">patch</a> to
|
|
|
|
|
<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits">llvm-commits</a>.
|
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|
When approved you may commit it yourself.</li>
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|
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|
2007-02-19 03:50:31 +00:00
|
|
|
<li>You are allowed to commit patches without approval which you think are
|
2009-04-05 12:37:44 +00:00
|
|
|
obvious. This is clearly a subjective decision — we simply expect
|
|
|
|
|
you to use good judgement. Examples include: fixing build breakage,
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|
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|
|
reverting obviously broken patches, documentation/comment changes, any
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|
|
|
|
other minor changes.</li>
|
|
|
|
|
|
|
|
|
|
<li>You are allowed to commit patches without approval to those portions 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
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|
|
|
|
cause commit access to be revoked.</li>
|
2007-02-19 03:50:31 +00:00
|
|
|
</ol>
|
2007-02-19 06:57:16 +00:00
|
|
|
|
|
|
|
|
<p>In any case, your changes are still subject to <a href="#reviews">code
|
2009-04-05 12:37:44 +00:00
|
|
|
review</a> (either before or after they are committed, depending on the
|
|
|
|
|
nature of the change). You are encouraged to review other peoples' patches
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|
|
|
|
as well, but you aren't required to.</p>
|
2007-02-19 03:50:31 +00:00
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
<!-- _______________________________________________________________________ -->
|
2007-02-19 05:43:04 +00:00
|
|
|
<div class="doc_subsection"> <a name="newwork">Making a Major Change</a></div>
|
|
|
|
|
<div class="doc_text">
|
2009-04-05 12:37:44 +00:00
|
|
|
<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>
|
2007-02-19 05:43:04 +00:00
|
|
|
|
2009-04-05 12:37:44 +00:00
|
|
|
<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>
|
2007-02-19 05:43:04 +00:00
|
|
|
|
2009-04-05 12:37:44 +00:00
|
|
|
<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>
|
2007-02-19 05:43:04 +00:00
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
<!-- _______________________________________________________________________ -->
|
2007-02-19 06:05:58 +00:00
|
|
|
<div class="doc_subsection"> <a name="incremental">Incremental Development</a>
|
2007-02-19 03:50:31 +00:00
|
|
|
</div>
|
|
|
|
|
<div class="doc_text">
|
2009-04-05 12:37:44 +00:00
|
|
|
<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
|
|
|
|
|
development and mainline development occur in the same pieces of code,
|
|
|
|
|
resolving merge conflicts can take a lot of time.</li>
|
|
|
|
|
|
|
|
|
|
<li>Other people in the community tend to ignore work on branches.</li>
|
|
|
|
|
|
|
|
|
|
<li>Huge changes (produced when a branch is merged back onto mainline) are
|
|
|
|
|
extremely difficult to <a href="#reviews">code review</a>.</li>
|
|
|
|
|
|
|
|
|
|
<li>Branches are not routinely tested by our nightly tester
|
|
|
|
|
infrastructure.</li>
|
|
|
|
|
|
|
|
|
|
<li>Changes developed as monolithic large changes often don't work until the
|
|
|
|
|
entire set of changes is done. Breaking it down into a set of smaller
|
|
|
|
|
changes increases the odds that any of the work will be committed to the
|
|
|
|
|
main repository.</li>
|
|
|
|
|
</ol>
|
2007-02-19 03:50:31 +00:00
|
|
|
|
2009-04-05 12:37:44 +00:00
|
|
|
<p>To address these problems, LLVM uses an incremental development style and we
|
|
|
|
|
require contributors to follow this practice when making a large/invasive
|
|
|
|
|
change. Some tips:</p>
|
|
|
|
|
|
|
|
|
|
<ul>
|
|
|
|
|
<li>Large/invasive changes usually have a number of secondary changes that are
|
|
|
|
|
required before the big change can be made (e.g. API cleanup, etc). These
|
|
|
|
|
sorts of changes can often be done before the major change is done,
|
|
|
|
|
independently of that work.</li>
|
|
|
|
|
|
|
|
|
|
<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>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>
|
2007-02-19 05:59:30 +00:00
|
|
|
|
2009-04-05 12:37:44 +00:00
|
|
|
<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 much easier to replace the underlying
|
|
|
|
|
implementation of the API. This implementation change is logically
|
|
|
|
|
separate from the API change.</li>
|
|
|
|
|
</ul>
|
2007-02-19 03:50:31 +00:00
|
|
|
|
2009-04-05 12:37:44 +00:00
|
|
|
<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 ask about the best way to go about making the change.</p>
|
2007-02-19 03:50:31 +00:00
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
<!-- _______________________________________________________________________ -->
|
2007-02-19 05:43:04 +00:00
|
|
|
<div class="doc_subsection"><a name="attribution">Attribution of
|
|
|
|
|
Changes</a></div>
|
2007-02-19 03:50:31 +00:00
|
|
|
<div class="doc_text">
|
2009-04-05 12:37:44 +00:00
|
|
|
<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 code written by J. Random Hacker" (this is noisy and
|
|
|
|
|
distracting). In practice, the revision control system keeps a perfect
|
|
|
|
|
history of who changed what, and the CREDITS.txt file describes higher-level
|
|
|
|
|
contributions. If you commit a patch for someone else, please say "patch
|
|
|
|
|
contributed by J. Random Hacker!" in the commit message.</p>
|
|
|
|
|
|
|
|
|
|
<p>Overall, please do not add contributor names to the source code.</p>
|
2007-02-19 03:50:31 +00:00
|
|
|
</div>
|
|
|
|
|
|
2007-02-14 07:22:19 +00:00
|
|
|
<!--=========================================================================-->
|
2007-02-19 06:19:16 +00:00
|
|
|
<div class="doc_section">
|
|
|
|
|
<a name="clp">Copyright, License, and Patents</a>
|
|
|
|
|
</div>
|
2007-02-14 07:22:19 +00:00
|
|
|
<!--=========================================================================-->
|
2007-02-19 03:50:31 +00:00
|
|
|
|
2007-02-14 07:22:19 +00:00
|
|
|
<div class="doc_text">
|
2009-04-05 12:37:44 +00:00
|
|
|
<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>.</p>
|
2007-02-14 07:22:19 +00:00
|
|
|
|
|
|
|
|
<div class="doc_notes">
|
2009-04-05 12:37:44 +00:00
|
|
|
<p style="text-align:center;font-weight:bold">NOTE: This section deals with
|
|
|
|
|
legal matters but does not provide legal advice. We are not lawyers, please
|
|
|
|
|
seek legal counsel from an attorney.</p>
|
2007-02-14 07:22:19 +00:00
|
|
|
</div>
|
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
<!-- _______________________________________________________________________ -->
|
|
|
|
|
<div class="doc_subsection"><a name="copyright">Copyright</a></div>
|
|
|
|
|
<div class="doc_text">
|
2009-04-05 12:37:44 +00:00
|
|
|
<p>For consistency and ease of management, the project requires the copyright
|
|
|
|
|
for all LLVM software to be held by a single copyright holder: the University
|
|
|
|
|
of Illinois (UIUC).</p>
|
2007-02-19 03:50:31 +00:00
|
|
|
|
2009-04-05 12:37:44 +00:00
|
|
|
<p>Although UIUC may eventually reassign the copyright of the software to
|
|
|
|
|
another entity (e.g. a dedicated non-profit "LLVM Organization") the intent
|
|
|
|
|
for the project is to always have a single entity hold the copyrights to LLVM
|
|
|
|
|
at any given time.</p>
|
|
|
|
|
|
|
|
|
|
<p>We believe that having a single copyright holder is in the best interests of
|
|
|
|
|
all developers and users as it greatly reduces the managerial burden for any
|
|
|
|
|
kind of administrative or technical decisions about LLVM. The goal of the
|
|
|
|
|
LLVM project is to always keep the code open and <a href="#license">licensed
|
|
|
|
|
under a very liberal license</a>.</p>
|
2007-02-14 07:22:19 +00:00
|
|
|
</div>
|
2007-02-19 03:50:31 +00:00
|
|
|
|
2007-02-14 07:22:19 +00:00
|
|
|
<!-- _______________________________________________________________________ -->
|
|
|
|
|
<div class="doc_subsection"><a name="license">License</a></div>
|
|
|
|
|
<div class="doc_text">
|
2009-04-05 12:37:44 +00:00
|
|
|
<p>We intend to keep LLVM perpetually open source and to use a liberal open
|
|
|
|
|
source license. The current license is the
|
|
|
|
|
<a href="http://www.opensource.org/licenses/UoI-NCSA.php">University of
|
2010-02-26 20:18:32 +00:00
|
|
|
Illinois/NCSA Open Source License</a>, which boils down to this:</p>
|
2009-04-05 12:37:44 +00:00
|
|
|
|
|
|
|
|
<ul>
|
|
|
|
|
<li>You can freely distribute LLVM.</li>
|
|
|
|
|
|
|
|
|
|
<li>You must retain the copyright notice if you redistribute LLVM.</li>
|
|
|
|
|
|
|
|
|
|
<li>Binaries derived from LLVM must reproduce the copyright notice (e.g. in
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an included readme file).</li>
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<li>You can't use our names to promote your LLVM derived products.</li>
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<li>There's no warranty on LLVM at all.</li>
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</ul>
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2007-02-19 03:50:31 +00:00
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2009-04-05 12:37:44 +00:00
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<p>We believe this fosters the widest adoption of LLVM because it <b>allows
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commercial products to be derived from LLVM</b> with few restrictions and
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without a requirement for making any derived works also open source (i.e.
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LLVM's license is not a "copyleft" license like the GPL). We suggest that you
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read the <a href="http://www.opensource.org/licenses/UoI-NCSA.php">License</a>
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if further clarification is needed.</p>
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2007-02-19 03:50:31 +00:00
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2009-04-05 12:37:44 +00:00
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<p>Note that the LLVM Project does distribute llvm-gcc, <b>which is GPL.</b>
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This means that anything "linked" into llvm-gcc must itself be compatible
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with the GPL, and must be releasable under the terms of the GPL. This
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implies that <b>any code linked into llvm-gcc and distributed to others may
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be subject to the viral aspects of the GPL</b> (for example, a proprietary
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code generator linked into llvm-gcc must be made available under the GPL).
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This is not a problem for code already distributed under a more liberal
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license (like the UIUC license), and does not affect code generated by
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llvm-gcc. It may be a problem if you intend to base commercial development
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on llvm-gcc without redistributing your source code.</p>
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2007-02-19 03:50:31 +00:00
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2009-04-05 12:37:44 +00:00
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<p>We have no plans to change the license of LLVM. If you have questions or
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comments about the license, please contact the
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<a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a>.</p>
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2007-02-14 07:22:19 +00:00
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</div>
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2007-02-19 06:05:58 +00:00
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<!-- _______________________________________________________________________ -->
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<div class="doc_subsection"><a name="patents">Patents</a></div>
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<div class="doc_text">
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2007-02-19 06:13:50 +00:00
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<p>To the best of our knowledge, LLVM does not infringe on any patents (we have
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actually removed code from LLVM in the past that was found to infringe).
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2009-04-05 12:37:44 +00:00
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Having code in LLVM that infringes on patents would violate an important goal
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of the project by making it hard or impossible to reuse the code for
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2007-02-19 06:15:33 +00:00
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arbitrary purposes (including commercial use).</p>
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2007-02-19 06:13:50 +00:00
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<p>When contributing code, we expect contributors to notify us of any potential
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2009-04-05 12:37:44 +00:00
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for patent-related trouble with their changes. If you or your employer own
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the rights to a patent and would like to contribute code to LLVM that relies
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on it, we require that the copyright owner sign an agreement that allows any
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other user of LLVM to freely use your patent. Please contact
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the <a href="mailto:llvm-oversight@cs.uiuc.edu">oversight group</a> for more
|
2007-02-19 06:13:50 +00:00
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details.</p>
|
2007-02-19 06:05:58 +00:00
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</div>
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2007-02-14 07:22:19 +00:00
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<!-- _______________________________________________________________________ -->
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<div class="doc_subsection"><a name="devagree">Developer Agreements</a></div>
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<div class="doc_text">
|
2009-04-05 12:37:44 +00:00
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<p>With regards to the LLVM copyright and licensing, developers agree to assign
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their copyrights to UIUC for any contribution made so that the entire
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software base can be managed by a single copyright holder. This implies that
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any contributions can be licensed under the license that the project
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uses.</p>
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<p>When contributing code, you also affirm that you are legally entitled to
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grant this copyright, personally or on behalf of your employer. If the code
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belongs to some other entity, please raise this issue with the oversight
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group before the code is committed.</p>
|
2007-02-14 07:22:19 +00:00
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</div>
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2007-02-13 09:06:01 +00:00
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<!-- *********************************************************************** -->
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<hr>
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<address>
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<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
|
2008-12-11 17:34:48 +00:00
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src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
|
2007-02-13 09:06:01 +00:00
|
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|
<a href="http://validator.w3.org/check/referer"><img
|
2008-12-11 18:23:24 +00:00
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src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
|
2007-02-19 06:15:33 +00:00
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Written by the
|
2007-02-14 07:57:48 +00:00
|
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<a href="mailto:llvm-oversight@cs.uiuc.edu">LLVM Oversight Group</a><br>
|
2007-02-13 09:06:01 +00:00
|
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<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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Last modified: $Date$
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</address>
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</body>
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</html>
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