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- <title>Bootstrapping the LLVM C/C++ Front-End</title>
+ <title>Building the LLVM C/C++ Front-End</title>
</head>
<body>
<div class="doc_title">
- Bootstrapping the LLVM C/C++ Front-End
+ Building the LLVM GCC Front-End
</div>
<ol>
- <li><a href="#cautionarynote">A Cautionary Note</a>
- <ul>
- <li><a href="#cygwin">Building under Cygwin</a></li>
- <li><a href="#aix">Building under AIX</a></li>
- </ul>
- </li>
- <li><a href="#instructions">Instructions</a></li>
+ <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 Brian R. Gaeke and
- <a href="http://nondot.org/sabre">Chris Lattner</a></p>
+ <p>Written by the LLVM Team</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
- <a name="cautionarynote">A Cautionary Note</a>
+ <a name="instructions">Building llvm-gcc from Source</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
-<p>This document is intended to explain the process of building the
-LLVM C/C++ front-end, based on GCC 3.4, from its source code. You
-would have to do this, for example, if you are porting LLVM to a new
-architecture or operating system.</p>
-<p><b>NOTE:</b> This is currently a somewhat fragile, error-prone
-process, and you should <b>only</b> try to do it if:</p>
+<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>you really, really, really can't use the binaries we distribute</li>
- <li>you are an elite GCC hacker.</li>
-</ol>
+ <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>We welcome patches to help make this process simpler.</p>
-</div>
+ <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_subsection">
- <a name="cygwin">Building under Cygwin</a>
+<div class="doc_code">
+<pre>
+svn co http://llvm.org/svn/llvm-project/llvm-gcc-4.0/trunk <i>dst-directory</i>
+</pre>
</div>
-<!--=========================================================================-->
-<div class="doc_text">
-<p>If you are building LLVM and the GCC front-end under Cygwin, please note that
-the LLVM and GCC makefiles do not correctly handle spaces in paths. To deal
-with this issue, make sure that your LLVM and GCC source and build trees are
-located in a top-level directory (like <tt>/cygdrive/c/llvm</tt> and
-<tt>/cygdrive/c/llvm-cfrontend</tt>), not in a directory that contains a space
-(which includes your "home directory", because it lives under the "Documents
-and Settings" directory). We welcome patches to fix this issue.
-</p>
-<p>It has been found that the GCC 3.3.3 compiler provided with recent Cygwin
-versions is incapable of compiling the LLVM CFE correctly. If your Cygwin
-installation includes GCC 3.3.3 we <i>strongly</i> recommend that you download
-GCC 3.4.3, build it separately, and use it for compiling LLVM CFE. This has been
-shown to work correctly.</p>
+<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>
-<!--=========================================================================-->
-<div class="doc_subsection">
- <a name="aix">Building under AIX</a>
+ <p>After that, the code can be be updated in the destination directory
+ using:</p>
+
+<div class="doc_code">
+<pre>svn update</pre>
</div>
-<!--=========================================================================-->
-<div class="doc_text">
-<p>If you are building LLVM and the GCC front-end under AIX, do NOT use GNU
-Binutils. They are not stable under AIX and may produce incorrect and/or
-invalid code. Instead, use the system assembler and linker.
-</p>
+ <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="instructions">Instructions</a>
+ <a name="license">Building the Ada front-end</a>
</div>
-<!-- *********************************************************************** -->
<div class="doc_text">
-<p>
+<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>Configure and build the LLVM libraries and tools using:</p>
-<pre>
- % cd llvm
- % ./configure --prefix=/some/path/you/can/install/to [options...]
- % gmake tools-only
-</pre>
- <p>This will build all of the LLVM tools and libraries. The <tt>--prefix</tt>
- option defaults to /usr/local (per configure standards) but unless you are a
- system administrator, you probably won't be able to install LLVM there because
- of permissions. Specify a path into which LLVM can be installed (e.g.
- <tt>--prefix=/home/user/llvm</tt>).</p>
-</li>
-
-<li><p>Add the directory containing the tools to your PATH.</p>
-<pre>
- % set path = ( `cd llvm/Debug/bin && pwd` $path )
-</pre></li>
+ <li>The only platform for which the Ada front-end is known to build is
+ 32 bit intel x86 running linux. It is unlikely to build for other
+ systems without some work.</li>
+ <li>The build requires having a compiler that supports Ada, C and C++.
+ The Ada front-end is written in Ada so an Ada compiler is needed to
+ build it. The LLVM parts of llvm-gcc are written in C++ so a C++
+ compiler is needed to build them. The rest of gcc is written in C.
+ Some linux distributions provide a version of gcc that supports all
+ three languages (the Ada part often comes as an add-on package to
+ the rest of gcc). Otherwise it is possible to combine two versions
+ of gcc, one that supports Ada and C (such as
+ <a href="http://libre.adacore.com/">GNAT GPL Edition</a>) and another
+ which supports C++, see below.</li>
+</ol>
-<li><p>Unpack the C/C++ front-end source into cfrontend/src.</p></li>
+<p>Supposing appropriate compilers are available, llvm-gcc with Ada support can
+ be built using the following recipe:</p>
-<li><p>Make "build" and "install" directories as siblings of the "src" tree.</p>
-<pre>
- % pwd
- /usr/local/example/cfrontend/src
- % cd ..
- % mkdir build install
- % set CFEINSTALL = `pwd`/install
-</pre></li>
+<ol>
+ <li>Download the <a href="http://llvm.org/releases/download.html">LLVM source</a>
+ and unpack it:
+<div class="doc_code">
+<pre>wget http://llvm.org/releases/2.2/llvm-2.2.tar.gz
+tar xzf llvm-2.2.tar.gz
+mv llvm-2.2 llvm</pre>
+</div>
-<li><p>Configure, build, and install the GCC front-end:</p>
+ or <a href="http://llvm.org/docs/GettingStarted.html#checkout">check out the
+ latest version from subversion</a>:
-<p>
-<b>Linux/x86:</b><br>
-<b>MacOS X/PowerPC</b> (requires dlcompat library):<br>
-<b>AIX/PowerPC:</b>
-</p>
+<div class="doc_code">
+<pre>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</pre>
+</div>
+ </li>
-<pre>
- % cd build
- % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
- --disable-shared --enable-languages=c,c++ --program-prefix=llvm-
- % gmake all; gmake install
-</pre>
+ <li>Download the
+ <a href="http://llvm.org/releases/download.html">llvm-gcc-4.2 source</a>
+ and unpack it:
-<p><b>Cygwin/x86:</b></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>
-<pre>
- % cd build
- % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
- --disable-shared --enable-languages=c,c++ --disable-c-mbchar \
- --program-prefix=llvm-
- % gmake all; gmake install
-</pre>
+ or <a href="http://llvm.org/docs/GettingStarted.html#checkout">check out the
+ latest version from subversion</a>:
-<p><b>Solaris/SPARC:</b></p>
+<div class="doc_code">
+<pre>svn co http://llvm.org/svn/llvm-project/llvm-gcc-4.2/trunk llvm-gcc-4.2</pre>
+</div>
+ </li>
-<p>
-For Solaris/SPARC, LLVM only supports the SPARC V9 architecture. Therefore,
-the configure command line should specify sparcv9, as shown below. Also,
-note that Solaris has trouble with various wide (multibyte) character
-functions from C as referenced from C++, so we typically configure with
---disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>).
-</p>
+ <li>Make a build directory <tt>llvm-objects</tt> for llvm and make it the
+ current directory:
+
+<div class="doc_code">
+<pre>mkdir llvm-objects
+cd llvm-objects</pre>
+</div>
+ </li>
+
+ <li>Configure LLVM (here it is configured to install into <tt>/usr/local</tt>):
+
+<div class="doc_code">
+<pre>../llvm/configure --prefix=/usr/local</pre>
+</div>
+
+ If you have a multi-compiler setup and the C++ compiler is not the
+ default, then you can configure like this:
+
+<div class="doc_code">
+<pre>CXX=<b>PATH_TO_C++_COMPILER</b> ../llvm/configure --prefix=/usr/local</pre>
+</div>
+ </li>
+
+ <li>Build LLVM:
+
+<div class="doc_code">
+<pre>make</pre>
+</div>
+ </li>
+
+ <li>Install LLVM (optional):
+<div class="doc_code">
+<pre>make install</pre>
+</div>
+ </li>
+
+ <li>Make a build directory <tt>llvm-gcc-4.2-objects</tt> for llvm-gcc and make it the
+ current directory:
+
+<div class="doc_code">
<pre>
- % cd build
- % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
- --disable-shared --enable-languages=c,c++ --host=sparcv9-sun-solaris2.8 \
- --disable-c-mbchar --program-prefix=llvm-
- % gmake all; gmake install
-</pre>
+cd ..
+mkdir llvm-gcc-4.2-objects
+cd llvm-gcc-4.2-objects</pre>
+</div>
+ </li>
+
+ <li>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>.
+
+<div class="doc_code">
+<pre>../llvm-gcc-4.2/configure --prefix=/usr/local --enable-languages=ada,c --enable-checking --enable-llvm=$PWD/../llvm-objects --disable-shared --disable-bootstrap --disable-multilib</pre>
+</div>
+
+ If you have a multi-compiler setup, then you can configure like this:
+<div class="doc_code">
- <p><b>Common Problem:</b> You may get error messages regarding the fact
- that LLVM does not support inline assembly. Here are two common
- fixes:</p>
-
- <ul>
- <li><p><b>Fix 1:</b> If you have system header files that include
- inline assembly, you may have to modify them to remove the inline
- assembly and install the modified versions in
- <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.</li>
-
- <li><b>Fix 2:</b> If you are building the C++ front-end on a CPU we
- haven't tried yet, you will probably have to edit the appropriate
- version of atomicity.h under
- <code>src/libstdc++-v3/config/cpu/<i>name-of-cpu</i>/atomicity.h</code>
- and apply a patch so that it does not use inline assembly.</li>
- </ul>
-
- <p><b>Porting to a new architecture:</b> If you are porting the front-end
- to a new architecture or compiling in a configuration that we have
- not tried previously, there are probably several changes you will have to make
- to the GCC target to get it to work correctly. These include:<p>
-
- <ul>
- <li>Often targets include special assembler or linker flags which
- <tt>gccas</tt>/<tt>gccld</tt> does not understand. In general, these can
- just be removed.</li>
- <li>LLVM currently does not support any floating point values other than
- 32-bit and 64-bit IEEE floating point. The primary effect of this is
- that you may have to map "long double" onto "double".</li>
- <li>The profiling hooks in GCC do not apply at all to the LLVM front-end.
- These may need to be disabled.</li>
- <li>No inline assembly for position independent code. At the LLVM level,
- everything is position independent.</li>
- <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>
- <li>You may have to disable multilib support in your target. Using multilib
- support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"
- options to the link line, which do not relate to LLVM and confuse
- <tt>gccld</tt>. To disable multilibs, delete any
- <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>
- <li>Did we mention that we don't support inline assembly? You'll probably
- have to add some fixinclude hacks to disable it in the system
- headers.</li>
- </ul>
-</li>
-
-<li><p>Put <tt>$CFEINSTALL/bin</tt> into your <tt>PATH</tt> environment
-variable.</p>
- <ul>
- <li>sh: <tt>export PATH=$CFEINSTALL/bin:$PATH</tt></li>
- <li>csh: <tt>setenv PATH $CFEINSTALL/bin:$PATH</tt></li>
- </ul>
-</li>
-
-<li><p>Go back into the LLVM source tree proper. Rerun configure, using
-the same options as the last time. This will cause the configuration to now find
-the newly built llvm-gcc and llvm-g++ executables. </p></li>
-
-<li><p>Rebuild your CVS tree. This shouldn't cause the whole thing to be
- rebuilt, but it should build the runtime libraries. After the tree is
- built, install the runtime libraries into your GCC front-end build tree.
- These are the commands you need.</p>
<pre>
- % gmake
- % gmake -C runtime install-bytecode
-</pre></li>
-
-<li><p>Optionally, build a symbol table for the newly installed runtime
-libraries. Although this step is optional, you are strongly encouraged to
-do this as the symbol tables will make a significant difference in your
-link times. Use the <tt>llvm-ranlib</tt> tool to do this, as follows:</p>
+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>Build and install the compiler:
+
+<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>
- % cd $CFEINSTALL/lib
- % llvm-ranlib libiberty.a
- % llvm-ranlib libstdc++.a
- % llvm-ranlib libsupc++.a
- % cd $CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm
- % llvm-ranlib libgcc.a
- % llvm-ranlib libgcov.a
+EXTRALANGS=,fortran
</pre>
+</div>
-<li><p>Test the newly-installed C frontend by one or more of the
-following means:</p>
- <ul>
- <li> running the feature & regression tests via <tt>make check</tt></li>
- <li> compiling and running a "hello, LLVM" program in C and C++.</li>
- <li> running the tests found in the <tt>llvm-test</tt> CVS module</li>
- </ul></li>
-</ol>
</div>
<!-- *********************************************************************** -->
</p>
<p>
-The software also has the following additional copyrights:
+More information is <a href="FAQ.html#license">available in the FAQ</a>.
</p>
-
-<pre>
-
-Copyright (c) 2003, 2004 University of Illinois at Urbana-Champaign.
-All rights reserved.
-
-Developed by:
-
- LLVM Team
-
- University of Illinois at Urbana-Champaign
-
- http://llvm.cs.uiuc.edu
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
-FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
-SOFTWARE.
-
-Copyright (c) 1994
-Hewlett-Packard Company
-
-Permission to use, copy, modify, distribute and sell this software
-and its documentation for any purpose is hereby granted without fee,
-provided that the above copyright notice appear in all copies and
-that both that copyright notice and this permission notice appear
-in supporting documentation. Hewlett-Packard Company makes no
-representations about the suitability of this software for any
-purpose. It is provided "as is" without express or implied warranty.
-
-Copyright (c) 1996, 1997, 1998, 1999
-Silicon Graphics Computer Systems, Inc.
-
-Permission to use, copy, modify, distribute and sell this software
-and its documentation for any purpose is hereby granted without fee,
-provided that the above copyright notice appear in all copies and
-that both that copyright notice and this permission notice appear
-in supporting documentation. Silicon Graphics makes no
-representations about the suitability of this software for any
-purpose. It is provided "as is" without express or implied warranty.
-</pre>
</div>
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- Brian Gaeke<br>
- <a href="http://llvm.cs.uiuc.edu">LLVM Compiler Infrastructure</a><br>
+ <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
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