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 |  | 
 | <div class="doc_title"> | 
 |   Bootstrapping the LLVM C/C++ 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="#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> | 
 | </div> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 | <div class="doc_section"> | 
 |   <a name="cautionarynote">A Cautionary Note</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> | 
 |  | 
 | <ol> | 
 |   <li>you really, really, really can't use the binaries we distribute</li> | 
 |   <li>you are an elite GCC hacker.</li> | 
 |   <li>you want to use the latest bits from CVS.</li> | 
 | </ol> | 
 |  | 
 | <p>We welcome patches to help make this process simpler.</p> | 
 | </div> | 
 |  | 
 | <!--=========================================================================--> | 
 | <div class="doc_subsection"> | 
 |   <a name="cygwin">Building under Cygwin</a> | 
 | </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 GCC front-end 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 the LLVM GCC front-end. This has been | 
 | shown to work correctly.</p> | 
 | <p>Some versions of Cygwin utilize an experimental version of GNU binutils that | 
 | will cause the GNU <tt>ld</tt> linker to fail an assertion when linking | 
 | components of the libstdc++. It is recommended that you replace the entire | 
 | binutils package with version 2.15 such that "<tt>ld --version</tt>" responds | 
 | with</p> | 
 | <pre>GNU ld version 2.15</pre> | 
 | not with:<br/> | 
 | <pre>GNU ld version 2.15.91 20040725</pre> | 
 | </div> | 
 |  | 
 | <!--=========================================================================--> | 
 | <div class="doc_subsection"><a name="aix">Building under AIX</a></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> | 
 | </div> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 | <div class="doc_section"> | 
 |   <a name="instructions">Instructions</a> | 
 | </div> | 
 | <!-- *********************************************************************** --> | 
 |  | 
 | <div class="doc_text"> | 
 | <p> | 
 | <ol> | 
 | <li><p>Configure and build the LLVM libraries and tools. There are two ways to | 
 | do this: either with <i>objdir</i> == <i>srcdir</i> or | 
 | <i>objdir</i> != <i>srcdir</i>. It is recommended  | 
 | that <i>srcdir</i> be the same as <i>objdir</i> for your LLVM tree (but note | 
 | that you should always use <i>srcdir</i> != <i>objdir</i> for llvm-gcc):</p> | 
 | <ul> | 
 |   <li>With <i>objdir</i> != <i>srcdir</i>:<pre> | 
 |  % cd <i>objdir</i> | 
 |  % <i>srcdir</i>/configure --prefix=/some/path/you/can/install/to [options...] | 
 |  % gmake tools-only | 
 |   </pre></li> | 
 |   <li>With <i>objdir</i> == <i>srcdir</i>:<pre> | 
 |  % cd llvm | 
 |  % ./configure --prefix=/some/path/you/can/install/to [options...] | 
 |  % gmake tools-only | 
 |   </pre></li> | 
 | </ul> | 
 | <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` $path ) | 
 | </pre></li> | 
 |  | 
 | <li><p>Unpack the C/C++ front-end source into cfrontend/src, either by | 
 |        untar'ing a cfrontend.source.tar.gz file or checking out CVS into this | 
 |        directory.</p></li> | 
 |  | 
 | <li><p>Make "build" and "install" directories as siblings of the "src" tree:</p> | 
 | <pre> | 
 |  % pwd | 
 |  /usr/local/example/cfrontend/src | 
 |  % cd .. | 
 |  % mkdir build install | 
 |  % set CFEINSTALL = `pwd`/install | 
 | </pre></li> | 
 |  | 
 |  | 
 | <li><p>Configure, build, and install the GCC front-end:</p> | 
 |  | 
 | <p> | 
 | <b>Linux/x86:</b><br> | 
 | <b>Linux/IA-64:</b><br> | 
 | <b>MacOS X/PowerPC</b> (requires dlcompat library):<br> | 
 | <b>AIX/PowerPC:</b> | 
 | </p> | 
 |  | 
 | <pre> | 
 |  % cd build | 
 |  % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \ | 
 |    --disable-shared --enable-languages=c,c++ --program-prefix=llvm- | 
 |  % gmake all; gmake install | 
 | </pre> | 
 |  | 
 | <p><b>Cygwin/x86:</b></p> | 
 |  | 
 | <pre> | 
 |  % cd build | 
 |  % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \ | 
 |    --disable-shared --enable-languages=c,c++ --disable-c-mbchar \ | 
 |    --program-prefix=llvm- | 
 |  % gmake all; gmake install | 
 | </pre> | 
 |  | 
 | <p><b>Solaris/SPARC:</b></p> | 
 |  | 
 | <p> | 
 | The GCC front-end can be configured for either SPARC V8 (32 bit) or SPARC V9 (64 | 
 | bit).  This changes, among other things, the sizes of integer types and the | 
 | macros defined for conditional compilation. | 
 | </p> | 
 |  | 
 | <p> | 
 | The SPARC V8 backend is still beta quality software.  Unless you are working on | 
 | the SPARC V8 backend, you should specify sparcv9 on the configure command line, | 
 | as shown below. Also, | 
 | note that Solaris has trouble with various wide (multibyte) character | 
 | functions from C as referenced from C++, so we typically configure with | 
 | --disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>). | 
 | </p> | 
 |  | 
 | <pre> | 
 |  % cd build | 
 |  % ../src/configure --prefix=$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> | 
 |  | 
 |  <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> | 
 | <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 | 
 | </pre> | 
 |  | 
 | <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> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 | <div class="doc_section"> | 
 |   <a name="license">License Information</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 | <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 | 
 | COPYING.LIB for more details. | 
 | </p> | 
 |  | 
 | <p> | 
 | The software also has the following additional copyrights: | 
 | </p> | 
 |  | 
 | <pre> | 
 |  | 
 | Copyright (c) 2003, 2004, 2005 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> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 |  | 
 | <hr> | 
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 |   Brian Gaeke<br> | 
 |   <a href="http://llvm.cs.uiuc.edu">LLVM Compiler Infrastructure</a><br> | 
 |   Last modified: $Date$ | 
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