<body>
<div class="doc_title">
- Building the LLVM C/C++ Front-End
+ Building the LLVM GCC Front-End
</div>
<ol>
- <li><a href="#instructions">Building llvm-gcc 4 from Source</a></li>
+ <li><a href="#instructions">Building llvm-gcc from Source</a></li>
<li><a href="#license">License Information</a></li>
</ol>
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<div class="doc_section">
- <a name="instructions">Building llvm-gcc 4 from Source</a>
+ <a name="instructions">Building llvm-gcc from Source</a>
</div>
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<div class="doc_text">
-<p>This section describes how to aquire and build llvm-gcc4, which is based on
-the GCC 4.0.1 front-end. This front-end supports C, C++, Objective-C, and
-Objective-C++. Note that the instructions for building this front-end are
-completely different (and much easier!) than those for building llvm-gcc3 in
+<p>This section describes how to acquire and build llvm-gcc 4.0 and 4.2, which are
+based on the GCC 4.0.1/4.2.1 front-ends respectively. Both front-ends support C,
+C++, Objective-C and Objective-C++. The 4.2 front-end also supports Ada and
+Fortran to some extent. 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-gcc4-x.y.source.tar.gz archive from the
+ <li><p>Retrieve the appropriate llvm-gcc4.x-y.z.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-gcc4 front end
- from a read-only mirror using subversion. To check out the code the
- first time use:</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 4.0 code
+ for first time use:</p>
<div class="doc_code">
<pre>
-svn co llvm.org/svn/llvm-project/llvm-gcc-4.0/trunk <i>dst-directory</i>
+svn co http://llvm.org/svn/llvm-project/llvm-gcc-4.0/trunk <i>dst-directory</i>
+</pre>
+</div>
+
+<p>To check out the 4.2 code 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>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-gcc4.</li>
+ 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. 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
+ <a href="http://libre.adacore.com/">GNAT GPL Edition</a>) and another
+ which supports C++, see below.</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/2.2/llvm-2.2.tar.gz
+tar xzf llvm-2.2.tar.gz
+mv llvm-2.2 llvm</pre>
+</div>
+
+ <p>or <a href="http://llvm.org/docs/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/2.2/llvm-gcc4.2-2.2.source.tar.gz
+tar xzf llvm-gcc4.2-2.2.source.tar.gz
+mv llvm-gcc4.2-2.2.source llvm-gcc-4.2</pre>
+</div>
+
+ <p>or <a href="http://llvm.org/docs/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=/usr/local</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=/usr/local</pre>
+</div>
+ </li>
+
+ <li><p>Build LLVM:</p>
+
+<div class="doc_code">
+<pre>make</pre>
+</div>
+ </li>
+
+ <li><p>Install LLVM (optional):</p>
+
+<div class="doc_code">
+<pre>make 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>).
+ 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=/usr/local --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-shared --disable-bootstrap --disable-multilib</pre>
+</div>
+
+ <p>If you have a multi-compiler setup, then you can configure like this:</p>
+<div class="doc_code">
+
+<pre>
+export CC=<b>PATH_TO_C_AND_ADA_COMPILER</b>
+export CXX=<b>PATH_TO_C++_COMPILER</b>
+../llvm-gcc-4.2/configure --prefix=/usr/local --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-shared --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>
+
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<div class="doc_section">
<a name="license">License Information</a>