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<div class="www_sectiontitle">LLVM Overview</div>

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<p>The LLVM Project is a collection of modular and reusable compiler and
   toolchain technologies.  Despite its name, LLVM has little to do with
   traditional virtual machines.  The name
   "LLVM" itself is not an acronym; it is the full name of the project.</p>

<p>LLVM began as a <a href="pubs/2004-01-30-CGO-LLVM.html">research
   project</a> at
   the <a href="http://cs.illinois.edu/">University of Illinois</a>, with
   the goal of providing a modern, SSA-based compilation strategy capable
   of supporting both static and dynamic compilation of arbitrary
   programming languages.  Since then, LLVM has
   grown to be an umbrella project consisting of a number of
   subprojects, many of which are being used in production by a wide variety of
   <a href="Users.html">commercial and open source</a> projects
   as well as being widely used in <a href="pubs/">academic research</a>.  Code
   in the LLVM project is licensed under the
   <a href="docs/DeveloperPolicy.html#new-llvm-project-license-framework">
   "Apache 2.0 License with LLVM exceptions"</a>
   </p>

<p>The primary sub-projects of LLVM are:</p>

<ol>
<li><p>The <b>LLVM Core</b> libraries provide a modern source- and
    target-independent <a href="docs/Passes.html">optimizer</a>, along with
    <a href="docs/CodeGenerator.html">code generation support</a> for many
    popular CPUs (as well as some less common ones!) These libraries are built
    around a <a href="docs/LangRef.html">well specified</a> code representation
    known as the LLVM intermediate representation ("LLVM IR").  The LLVM Core
    libraries are <a href="docs/">well documented</a>, and it is particularly
    easy to invent your own language (or port an existing compiler) to use
    <a href="docs/tutorial/">LLVM as an optimizer and code generator</a>.</p>
</li>

<li><p><b><a href="http://clang.llvm.org">Clang</a></b> is an "LLVM native"
    C/C++/Objective-C compiler, which aims to deliver amazingly fast compiles,
    extremely useful <a href="http://clang.llvm.org/diagnostics.html">error
    and warning messages</a> and to provide a platform for building great
    source level tools.
    The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a> and
    <a href="https://clang.llvm.org/extra/clang-tidy/">clang-tidy</a> are
    tools that automatically find bugs in your code, and are great examples of the
    sort of tools that can be built using the Clang frontend as a library to
    parse C/C++ code.</p></li>

<li><p>The <b><a href="http://lldb.llvm.org">LLDB</a></b> project builds on
    libraries provided by LLVM and Clang to provide a great native debugger.
    It uses the Clang ASTs and expression parser, LLVM JIT, LLVM disassembler,
    etc so that it provides an experience that "just works".  It is also
    blazing fast and much more memory efficient than GDB at loading symbols.
    </p></li>

<li><p>The <b><a href="http://libcxx.llvm.org">libc++</a></b> and
    <b><a href="http://libcxxabi.llvm.org">libc++ ABI</a></b> projects provide
    a standard conformant and high-performance implementation of the C++
    Standard Library, including full support for C++11 and C++14.</p></li>

<li><p>The <b><a href="http://compiler-rt.llvm.org">compiler-rt</a></b> project
    provides highly tuned implementations of the low-level code generator
    support routines like "<tt>__fixunsdfdi</tt>" and other calls generated when
    a target doesn't have a short sequence of native instructions to implement
    a core IR operation. It also provides implementations of run-time libraries
    for dynamic testing tools such as
    <a href="http://clang.llvm.org/docs/AddressSanitizer.html">AddressSanitizer</a>,
    <a href="http://clang.llvm.org/docs/ThreadSanitizer.html">ThreadSanitizer</a>,
    <a href="http://clang.llvm.org/docs/MemorySanitizer.html">MemorySanitizer</a>,
    and
    <a href="http://clang.llvm.org/docs/DataFlowSanitizer.html">DataFlowSanitizer</a>.
    </p></li>

<li><p>The <b><a href="http://mlir.llvm.org">MLIR</a></b> subproject is a novel
    approach to building reusable and extensible compiler infrastructure. MLIR
    aims to address software fragmentation, improve compilation for heterogeneous
    hardware, significantly reduce the cost of building domain specific compilers,
    and aid in connecting existing compilers together.
    </p></li>

<li><p>The <b><a href="http://openmp.llvm.org">OpenMP</a></b> subproject
    provides an <a href="http://openmp.org">OpenMP</a> runtime for use with the
    OpenMP implementation in Clang.</p></li>

<li><p>The <b><a href="http://polly.llvm.org/">polly</a></b> project implements
    a suite of cache-locality optimizations as well as auto-parallelism and
    vectorization using a polyhedral model.</p></li>

<li><p>The <b><a href="http://libclc.llvm.org/">libclc</a></b> project aims to
    implement the OpenCL standard library.</p></li>

<li><p>The <b><a href="http://klee.llvm.org">klee</a></b> project implements a
    "symbolic virtual machine" which uses a theorem prover to try to evaluate
    all dynamic paths through a program in an effort to find bugs and to prove
    properties of functions.  A major feature of klee is that it can produce a
    testcase in the event that it detects a bug.</p></li>

<li><p>The <b><a href="http://lld.llvm.org/">LLD</a></b> project is a new
    linker. That is a drop-in replacement for system linkers
    and runs much faster.</p></li>
</ol>

<p>In addition to official subprojects of LLVM, there are a broad variety of
other projects that <a href="/ProjectsWithLLVM/">use components
of LLVM for various tasks</a>.  Through these external projects you can use
LLVM to compile Ruby, Python, Haskell, Rust, D, PHP, Pure, Lua, and a number of
other languages. A major strength of LLVM is its versatility, flexibility, and
reusability, which is why it is being used for such a wide variety of different
tasks: everything from doing light-weight JIT compiles of embedded languages
like Lua to compiling Fortran code for massive super computers.</p>

<p>As much as everything else, LLVM has a broad and friendly community of people
who are interested in building great low-level tools.  If you are interested in
getting involved, a good first place is to skim the <a
href="http://blog.llvm.org">LLVM Blog</a> and to sign up for the <a
href="http://lists.llvm.org/mailman/listinfo/llvm-dev">LLVM Developer mailing
list</a>.  For information on how to send in a patch, get commit access, and
copyright and license topics, please see <a href="docs/DeveloperPolicy.html">the
LLVM Developer Policy</a>.
</p>

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<div class="www_sectiontitle">Latest LLVM Release!</div>

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  <p><b>25 Februrary 2021</b>: LLVM 11.1.0 is now <a href="releases/"><b>available
  for download</b></a>!  LLVM is publicly available under an open source <a
  href="releases/11.1.0/LICENSE.TXT">License</a>.  Also, you might want to
  check out <a href="docs/ReleaseNotes.html#whatsnew"><b>the new
  features</b></a> in Git that will appear in the next LLVM release.  If
  you want them early, <a href="releases/">download LLVM</a> through
  anonymous Git.</p>
</div>

<div class="www_sectiontitle">ACM Software System Award!</div>

<div class="www_text">
  <p>LLVM has been awarded the <b>2012 ACM Software System Award</b>!
     This award is given by ACM to <i>one</i> software system worldwide
   every year.
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     LLVM is <a href="http://awards.acm.org/software_system/year.cfm">
     in highly distinguished company</a>!
     Click on any of the individual recipients' names on that page for
     the detailed citation describing the award.
  </p>
</div>

<div class="www_sectiontitle">GitHub Migration</div>

<div class="www_text">
  <p>Completed! Many thanks to all the participants</p>
</div>

<div class="www_sectiontitle">Upcoming Releases</div>

<div class="www_text">

<p><b>LLVM Release Schedule:</b></p>
<ul>
<li>12.0.0:
<ul>
  <li>Jan 26: release/12.x branch, 12.0.0-rc1</li>
  <li>Feb 23: 12.0.0-rc2</li>
  <li>Mar  2: 12.0.0-final</li>
</ul>
</ul>

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<div class="www_sectiontitle">Developer&nbsp;Meetings</div>

<div class="www_text">
<p>Upcoming:
<br>
<a href="/devmtg/2020-09/">October 6-8, 2020</a><br>
</p>
<p>Proceedings from past meetings:</p>
<ul>
<li><a href="/devmtg/2019-10/">October 22-23, 2019</a></li>
<li><a href="/devmtg/2019-04/">April 8-9, 2019</a></li>
<li><a href="/devmtg/2018-10/">October 17-18, 2018</a></li>
<li><a href="/devmtg/2018-04/">April 16-17, 2018</a></li>
<li><a href="/devmtg/2017-10/">October 18-19, 2017</a></li>
<li><a href="/devmtg/2017-03/">March 27-28, 2017</a></li>
<li><a href="/devmtg/2016-11/">November 3-4, 2016</a></li>
<li><a href="/devmtg/2016-03/">March 17-18, 2016</a></li>
<li><a href="/devmtg/2015-10/">October 29-30, 2015</a></li>
<li><a href="/devmtg/2015-04/">April 13-14, 2015</a></li>
<li><a href="/devmtg/2014-10/">October 28-29, 2014</a></li>
<li><a href="/devmtg/2014-04/">April 7-8, 2014</a></li>
<li><a href="/devmtg/2013-11/">Nov 6-7, 2013</a></li>
<li><a href="/devmtg/2013-04/">April 29-30, 2013</a></li>
<li><a href="/devmtg/2012-11/">November 7-8, 2012</a></li>
<li><a href="/devmtg/2012-04-12/">April 12, 2012</a></li>
<li><a href="/devmtg/2011-11/">November 18, 2011</a></li>
<li><a href="/devmtg/2011-09-16/">September 2011</a></li>
<li><a href="/devmtg/2010-11/">November 2010</a></li>
<li><a href="/devmtg/2009-10/">October 2009</a></li>
<li><a href="/devmtg/2008-08/">August 2008</a></li>
<li><a href="/devmtg/2007-05/">May 2007</a></li>
</ul>
</div>

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