llvm.org GIT mirror llvm / release_24 docs / GCCFEBuildInstrs.html
release_24

Tree @release_24 (Download .tar.gz)

GCCFEBuildInstrs.html @release_24raw · history · blame

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
                      "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <link rel="stylesheet" href="llvm.css" type="text/css" media="screen">
  <title>Building the LLVM GCC Front-End</title>
</head>
<body>

<div class="doc_title">
  Building the LLVM GCC Front-End
</div>

<ol>
  <li><a href="#instructions">Building llvm-gcc from Source</a></li>
  <li><a href="#license">License Information</a></li>
</ol>

<div class="doc_author">    
  <p>Written by the LLVM Team</p>
</div>

<!-- *********************************************************************** -->
<div class="doc_section">
  <a name="instructions">Building llvm-gcc from Source</a>
</div>
<!-- *********************************************************************** -->

<div class="doc_text">

<p>This section describes how to acquire and build llvm-gcc 4.2, which is based
on the GCC 4.2.1 front-end.  Supported languages are Ada, C, C++, Fortran,
Objective-C and Objective-C++.  Note that the instructions for building these
front-ends are completely different (and much easier!) than those for building
llvm-gcc3 in the past.</p>

<ol>
  <li><p>Retrieve the appropriate llvm-gcc-4.2-x.y.source.tar.gz archive from the
         <a href="http://llvm.org/releases/">llvm web site</a>.</p>

      <p>It is also possible to download the sources of the llvm-gcc front end
         from a read-only mirror using subversion.  To check out the 4.2 code
         for first time use:</p>

<div class="doc_code">
<pre>
svn co http://llvm.org/svn/llvm-project/llvm-gcc-4.2/trunk <i>dst-directory</i>
</pre>
</div>

      <p>After that, the code can be be updated in the destination directory
         using:</p>

<div class="doc_code">
<pre>svn update</pre>
</div>

      <p>The mirror is brought up to date every evening.</p></li>

  <li>Follow the directions in the top-level <tt>README.LLVM</tt> file for
      up-to-date instructions on how to build llvm-gcc.  See below for building
      with support for Ada or Fortran.
</ol>

</div>

<!-- *********************************************************************** -->
<div class="doc_section">
  <a name="license">Building the Ada front-end</a>
</div>

<div class="doc_text">
<p>Building with support for Ada amounts to following the directions in the
top-level <tt>README.LLVM</tt> file, adding ",ada" to EXTRALANGS, for example:
<tt>EXTRALANGS=,ada</tt></p>

<p>There are some complications however:</p>

<ol>
  <li><p>The only platform for which the Ada front-end is known to build is
      32 bit intel x86 running linux.  It is unlikely to build for other
      systems without some work.</p></li>
  <li><p>The build requires having a compiler that supports Ada, C and C++.
      The Ada front-end is written in Ada so an Ada compiler is needed to
      build it.  Compilers known to work with the
      <a href="http://llvm.org/releases/download.html">LLVM 2.3 release</a>
      are <a href="http://gcc.gnu.org/releases.html">gcc-4.2</a> and the
      2005, 2006 and 2007 versions of the
      <a href="http://libre.adacore.com/">GNAT GPL Edition</a>.
      The LLVM parts of llvm-gcc are written in C++ so a C++ compiler is
      needed to build them.  The rest of gcc is written in C.
      Some linux distributions provide a version of gcc that supports all
      three languages (the Ada part often comes as an add-on package to
      the rest of gcc).  Otherwise it is possible to combine two versions
      of gcc, one that supports Ada and C (such as the
      <a href="http://libre.adacore.com/">2007 GNAT GPL Edition</a>)
      and another which supports C++, see below.</p></li>
  <li><p>Because the Ada front-end is experimental, it is wise to build the
      compiler with checking enabled.  This causes it to run much slower, but
      helps catch mistakes in the compiler (please report any problems using
      <a href="http://llvm.org/bugs">LLVM bugzilla</a>).</p></li>
</ol>

<p>Supposing appropriate compilers are available, llvm-gcc with Ada support can
   be built on an x86-32 linux box using the following recipe:</p>

<ol>
  <li><p>Download the <a href="http://llvm.org/releases/download.html">LLVM source</a>
      and unpack it:</p>

<div class="doc_code">
<pre>wget http://llvm.org/releases/2.3/llvm-2.3.tar.gz
tar xzf llvm-2.3.tar.gz
mv llvm-2.3 llvm</pre>
</div>

      <p>or <a href="GettingStarted.html#checkout">check out the
      latest version from subversion</a>:</p>

<div class="doc_code">
<pre>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</pre>
</div>
      </li>

  <li><p>Download the
      <a href="http://llvm.org/releases/download.html">llvm-gcc-4.2 source</a>
      and unpack it:</p>

<div class="doc_code">
<pre>wget http://llvm.org/releases/2.3/llvm-gcc-4.2-2.3.source.tar.gz
tar xzf llvm-gcc-4.2-2.3.source.tar.gz
mv llvm-gcc4.2-2.3.source llvm-gcc-4.2</pre>
</div>

      <p>or <a href="GettingStarted.html#checkout">check out the
      latest version from subversion</a>:</p>

<div class="doc_code">
<pre>svn co http://llvm.org/svn/llvm-project/llvm-gcc-4.2/trunk llvm-gcc-4.2</pre>
</div>
      </li>

  <li><p>Make a build directory <tt>llvm-objects</tt> for llvm and make it the
      current directory:</p>

<div class="doc_code">
<pre>mkdir llvm-objects
cd llvm-objects</pre>
</div>
      </li>

  <li><p>Configure LLVM (here it is configured to install into <tt>/usr/local</tt>):</p>

<div class="doc_code">
<pre>../llvm/configure --prefix=<b>/usr/local</b></pre>
</div>

      <p>If you have a multi-compiler setup and the C++ compiler is not the
      default, then you can configure like this:</p>

<div class="doc_code">
<pre>CXX=<b>PATH_TO_C++_COMPILER</b> ../llvm/configure --prefix=<b>/usr/local</b></pre>
</div>
      </li>

  <li><p>Build LLVM with checking enabled (use <tt>ENABLE_OPTIMIZED=1</tt> to
         build without checking):</p>

<div class="doc_code">
<pre>make ENABLE_OPTIMIZED=0</pre>
</div>
      </li>

  <li><p>Install LLVM (optional):</p>

<div class="doc_code">
<pre>make ENABLE_OPTIMIZED=0 install</pre>
</div>
      </li>

  <li><p>Make a build directory <tt>llvm-gcc-4.2-objects</tt> for llvm-gcc and make it the
      current directory:</p>

<div class="doc_code">
<pre>
cd ..
mkdir llvm-gcc-4.2-objects
cd llvm-gcc-4.2-objects</pre>
</div>
      </li>

  <li><p>Configure llvm-gcc (here it is configured to install into <tt>/usr/local</tt>).
      The <tt>--enable-checking</tt> flag turns on sanity checks inside the compiler.
      If you omit it then LLVM should be built with <tt>make ENABLE_OPTIMIZED=1</tt>.
      Additional languages can be appended to the --enable-languages switch,
      for example <tt>--enable-languages=ada,c,c++</tt>.</p>

<div class="doc_code">
<pre>../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-bootstrap --disable-multilib</pre>
</div>

      <p>If you have a multi-compiler setup, then you can configure like this:</p>
<div class="doc_code">

<pre>
export CC=<b>PATH_TO_C_AND_ADA_COMPILER</b>
export CXX=<b>PATH_TO_C++_COMPILER</b>
../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-bootstrap --disable-multilib</pre>
</div>
      </li>

  <li><p>Build and install the compiler:</p>

<div class="doc_code">
<pre>make
make install</pre>
</div>
      </li>
</ol>

</div>

<!-- *********************************************************************** -->
<div class="doc_section">
  <a name="license">Building the Fortran front-end</a>
</div>

<div class="doc_text">
<p>
To build with support for Fortran, follow the directions in the top-level
<tt>README.LLVM</tt> file, adding ",fortran" to EXTRALANGS, for example:</p>

<div class="doc_code">
<pre>
EXTRALANGS=,fortran
</pre>
</div>

</div>

<!-- *********************************************************************** -->
<div class="doc_section">
  <a name="license">License Information</a>
</div>

<div class="doc_text">
<p>
The LLVM GCC frontend is licensed to you under the GNU General Public License
and the GNU Lesser General Public License.  Please see the files COPYING and
COPYING.LIB for more details.
</p>

<p>
More information is <a href="FAQ.html#license">available in the FAQ</a>.
</p>
</div>

<!-- *********************************************************************** -->

<hr>
<address>
  <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
  src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
  <a href="http://validator.w3.org/check/referer"><img
  src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>

  <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
  Last modified: $Date$
</address>

</body>
</html>