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++
+ build it. What is more, the Ada compiler must not be more recent
+ than what it is trying to compile, otherwise the build will fail.
+ This rules out gcc-4.3 (but not gcc-4.2) and also the
+ <a href="http://libre.adacore.com/">2007 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
- <a href="http://libre.adacore.com/">GNAT GPL Edition</a>) and another
- which supports C++, see below.</p></li>
+ of gcc, one that supports Ada and C (such as the
+ <a href="http://libre.adacore.com/">2006 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 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
<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>
+<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=/usr/local</pre>
+<pre>CXX=<b>PATH_TO_C++_COMPILER</b> ../llvm/configure --prefix=<b>/usr/local</b></pre>
</div>
</li>
- <li><p>Build LLVM:</p>
+ <li><p>Build LLVM with checking enabled (use <tt>ENABLE_OPTIMIZED=1</tt> to
+ build without checking):</p>
<div class="doc_code">
-<pre>make</pre>
+<pre>make ENABLE_OPTIMIZED=0</pre>
</div>
</li>
</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 must 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=/usr/local --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-shared --disable-bootstrap --disable-multilib</pre>
+<pre>../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c --enable-checking --enable-llvm=$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>
<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=$PWD/../llvm-objects --disable-shared --disable-bootstrap --disable-multilib</pre>
+../llvm-gcc-4.2/configure --prefix=<b>/usr/local</b> --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-shared --disable-bootstrap --disable-multilib</pre>
</div>
</li>