</head>
<body>
-<div class="doc_title">
+<h1>
Building the LLVM GCC Front-End
-</div>
+</h1>
<ol>
<li><a href="#instructions">Building llvm-gcc from Source</a></li>
+ <li><a href="#ada">Building the Ada front-end</a></li>
+ <li><a href="#fortran">Building the Fortran front-end</a></li>
<li><a href="#license">License Information</a></li>
</ol>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="instructions">Building llvm-gcc from Source</a>
-</div>
+<h2><a name="instructions">Building llvm-gcc from Source</a></h2>
<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<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,
</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="license">Building the Ada front-end</a>
-</div>
+<h2><a name="ada">Building the Ada front-end</a></h2>
+<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<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>
<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 2.4 release</a>
+ <a href="http://llvm.org/releases/download.html">LLVM 2.7 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>.
+ <b>GNAT GPL 2008, gcc-4.3 and later will not work</b>.
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
<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>
+ <a href="http://llvm.org/bugs/">LLVM bugzilla</a>).</p></li>
+ <li><p>The Ada front-end <a href="http://llvm.org/PR2007">fails to
+ bootstrap</a>, due to lack of LLVM support for
+ <tt>setjmp</tt>/<tt>longjmp</tt> style exception handling (used
+ internally by the compiler), so you must specify
+ <tt>--disable-bootstrap</tt>.</p></li>
</ol>
<p>Supposing appropriate compilers are available, llvm-gcc with Ada support can
and unpack it:</p>
<pre class="doc_code">
-wget http://llvm.org/releases/2.4/llvm-2.4.tar.gz
-tar xzf llvm-2.4.tar.gz
-mv llvm-2.4 llvm
+wget http://llvm.org/releases/2.7/llvm-2.7.tgz
+tar xzf llvm-2.7.tgz
+mv llvm-2.7 llvm
</pre>
<p>or <a href="GettingStarted.html#checkout">check out the
and unpack it:</p>
<pre class="doc_code">
-wget http://llvm.org/releases/2.4/llvm-gcc-4.2-2.4.source.tar.gz
-tar xzf llvm-gcc-4.2-2.4.source.tar.gz
-mv llvm-gcc4.2-2.4.source llvm-gcc-4.2
+wget http://llvm.org/releases/2.7/llvm-gcc-4.2-2.7.source.tgz
+tar xzf llvm-gcc-4.2-2.7.source.tgz
+mv llvm-gcc-4.2-2.7.source llvm-gcc-4.2
</pre>
<p>or <a href="GettingStarted.html#checkout">check out the
<li><p>Configure LLVM (here it is configured to install into <tt>/usr/local</tt>):</p>
<pre class="doc_code">
-../llvm/configure --prefix=<b>/usr/local</b>
+../llvm/configure --prefix=<b>/usr/local</b> --enable-optimized --enable-assertions
</pre>
<p>If you have a multi-compiler setup and the C++ compiler is not the
default, then you can configure like this:</p>
<pre class="doc_code">
-CXX=<b>PATH_TO_C++_COMPILER</b> ../llvm/configure --prefix=<b>/usr/local</b>
+CXX=<b>PATH_TO_C++_COMPILER</b> ../llvm/configure --prefix=<b>/usr/local</b> --enable-optimized --enable-assertions
</pre>
+
+ <p>To compile without checking (not recommended), replace
+ <tt>--enable-assertions</tt> with <tt>--disable-assertions</tt>.</p>
+
</li>
- <li><p>Build LLVM with checking enabled (use <tt>ENABLE_OPTIMIZED=1</tt> to
- build without checking):</p>
+ <li><p>Build LLVM:</p>
<pre class="doc_code">
-make ENABLE_OPTIMIZED=0
+make
</pre>
</li>
<li><p>Install LLVM (optional):</p>
<pre class="doc_code">
-make ENABLE_OPTIMIZED=0 install
+make install
</pre>
</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,
+ To turn off these checks (not recommended), replace <tt>--enable-checking</tt>
+ with <tt>--disable-checking</tt>.
+ Additional languages can be appended to the <tt>--enable-languages</tt> switch,
for example <tt>--enable-languages=ada,c,c++</tt>.</p>
<pre class="doc_code">
-../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-bootstrap --disable-multilib
+../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c \
+ --enable-checking --enable-llvm=$PWD/../llvm-objects \
+ --disable-bootstrap --disable-multilib
</pre>
<p>If you have a multi-compiler setup, then you can configure like this:</p>
<pre class="doc_code">
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=$PWD/../llvm-objects --disable-bootstrap --disable-multilib
+../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c \
+ --enable-checking --enable-llvm=$PWD/../llvm-objects \
+ --disable-bootstrap --disable-multilib
</pre>
</li>
</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="license">Building the Fortran front-end</a>
-</div>
+<h2><a name="fortran">Building the Fortran front-end</a></h2>
+<!-- *********************************************************************** -->
-<div class="doc_text">
-<p>
-To build with support for Fortran, follow the directions in the top-level
+<div>
+<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>
<pre class="doc_code">
</div>
<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="license">License Information</a>
-</div>
+<h2><a name="license">License Information</a></h2>
+<!-- *********************************************************************** -->
-<div class="doc_text">
+<div>
<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
<a href="http://validator.w3.org/check/referer"><img
src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
- <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
+ <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
</address>
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