<p>The second piece is the GCC front end. This component provides a version of
GCC that compiles C and C++ code into LLVM bytecode. Currently, the GCC front
-end is a modified version of GCC 3.4 (we track the GCC 3.4 development). Once
+end uses the GCC parser to convert code to LLVM. Once
compiled into LLVM bytecode, a program can be manipulated with the LLVM tools
from the LLVM suite.</p>
<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
bugs in the compiler. In particular, several versions of GCC crash when trying
to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
-successfully with them (however, see below). Other versions of GCC will
-probably work as well. GCC versions listed
+successfully with them (however, see important notes below). Other versions
+of GCC will probably work as well. GCC versions listed
here are known to not work. If you are using one of these versions, please try
to upgrade your GCC to something more recent. If you run into a problem with a
version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
possibly others) does not compile LLVM correctly (it appears that exception
handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
to a newer version of GCC.</p>
+<p><b>GCC 3.4.0</b> on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
+ code generator, causing an infinite loop in the llvm-gcc build when built
+ with optimizations enabled (i.e. a release build).</p>
+<p><b>GCC 3.4.2</b> on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
+ code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
+ correctly compiles LLVM at -O2. A work around is to build release LLVM
+ builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
+<p><b>GCC 3.4.x</b> on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
+ miscompiles portions of LLVM</a>.</p>
<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
miscompile LLVM.</p>
<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
code. LLVM will appear to mostly work but will be buggy, e.g. failing
portions of its testsuite.</p>
+<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
+platforms compiling md5.c gets a mangled constant.</p>
<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
defined in a discarded section. You can safely ignore these messages as they are
labels:</p>
<ul>
+<li>Release 2.0: <b>RELEASE_20</b></li>
<li>Release 1.9: <b>RELEASE_19</b></li>
<li>Release 1.8: <b>RELEASE_18</b></li>
<li>Release 1.7: <b>RELEASE_17</b></li>
configured by the LLVM configure script as well as automatically updated when
you run <tt>cvs update</tt>.</p>
-<p>If you would like to get the GCC 3.4 front end source code, you can also get it from the CVS repository:</p>
-
-<pre>
- cvs -z3 -d :pserver:anon@llvm.org:/var/cvs/llvm co llvm-gcc
-</pre>
-
-<p>Please note that you must follow <a href="CFEBuildInstrs.html">these
-instructions</a> to successfully build the LLVM GCC front-end.</p>
+<p>If you would like to get the GCC front end source code, you can also get it
+and build it yourself. Please follow <a href="CFEBuildInstrs.html">these
+instructions</a> to successfully get and build the LLVM GCC front-end.</p>
</div>
<div class="doc_text">
-<p>Before configuring and compiling the LLVM suite, you need to extract the LLVM
-GCC front end from the binary distribution. It is used for building the
-bytecode libraries later used by the GCC front end for linking programs, and its
-location must be specified when the LLVM suite is configured.</p>
+<p>Before configuring and compiling the LLVM suite, you can optionally extract the
+LLVM GCC front end from the binary distribution. It is used for running the
+llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally
+<a href="CFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
+main LLVM repository.</p>
<p>To install the GCC front end, do the following:</p>
-</tt></li>
</ol>
+<p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
+llvm-g++ to some directory in your path. When you configure LLVM, it will
+automatically detect llvm-gcc's presence (if it is in your path) enabling its
+use in llvm-test. Note that you can always build or install llvm-gcc at any
+pointer after building the main LLVM repository: just reconfigure llvm and
+llvm-test will pick it up.
+</p>
+
<p>The binary versions of the GCC front end may not suit all of your needs. For
example, the binary distribution may include an old version of a system header
file, not "fix" a header file that needs to be fixed for GCC, or it may be
<p>In cases like these, you may want to try <a
href="CFEBuildInstrs.html">building the GCC front end from source.</a> This is
-not for the faint of heart, so be forewarned.</p>
+much easier now than it was in the past.</p>
</div>
directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
causing a re-linking of LLC.<br><br>
- <dt><tt><b>NightlyTest.pl</b></tt> and
+ <dt><tt><b>NewNightlyTest.pl</b></tt> and
<tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
cron script to generate nightly status reports of the functionality of
tools, and the results can be seen by following the appropriate link on
projects / oota-llvm.git / blobdiff