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7 <title>Bootstrapping the LLVM C/C++ Front-End</title>
11 <div class="doc_title">
12 Bootstrapping the LLVM C/C++ Front-End
16 <li><a href="#cautionarynote">A Cautionary Note</a>
18 <li><a href="#cygwin">Building under Cygwin</a></li>
19 <li><a href="#aix">Building under AIX</a></li>
22 <li><a href="#instructions">Instructions</a></li>
23 <li><a href="#license">License Information</a></li>
26 <div class="doc_author">
27 <p>Written by Brian R. Gaeke and
28 <a href="http://nondot.org/sabre">Chris Lattner</a></p>
31 <!-- *********************************************************************** -->
32 <div class="doc_section">
33 <a name="cautionarynote">A Cautionary Note</a>
35 <!-- *********************************************************************** -->
37 <div class="doc_text">
38 <p>This document is intended to explain the process of building the
39 LLVM C/C++ front-end, based on GCC 3.4, from its source code. You
40 would have to do this, for example, if you are porting LLVM to a new
41 architecture or operating system.</p>
43 <p><b>NOTE:</b> This is currently a somewhat fragile, error-prone
44 process, and you should <b>only</b> try to do it if:</p>
47 <li>you really, really, really can't use the binaries we distribute</li>
48 <li>you are an elite GCC hacker.</li>
49 <li>you want to use the latest bits from CVS.</li>
52 <p>We welcome patches to help make this process simpler.</p>
55 <!--=========================================================================-->
56 <div class="doc_subsection">
57 <a name="cygwin">Building under Cygwin</a>
59 <!--=========================================================================-->
61 <div class="doc_text">
62 <p>If you are building LLVM and the GCC front-end under Cygwin, please note that
63 the LLVM and GCC makefiles do not correctly handle spaces in paths. To deal
64 with this issue, make sure that your LLVM and GCC source and build trees are
65 located in a top-level directory (like <tt>/cygdrive/c/llvm</tt> and
66 <tt>/cygdrive/c/llvm-cfrontend</tt>), not in a directory that contains a space
67 (which includes your "home directory", because it lives under the "Documents
68 and Settings" directory). We welcome patches to fix this issue.
70 <p>It has been found that the GCC 3.3.3 compiler provided with recent Cygwin
71 versions is incapable of compiling the LLVM CFE correctly. If your Cygwin
72 installation includes GCC 3.3.3 we <i>strongly</i> recommend that you download
73 GCC 3.4.3, build it separately, and use it for compiling LLVM CFE. This has been
74 shown to work correctly.</p>
75 <p>Some versions of Cygwin utilize an experimental version of GNU binutils that
76 will cause the GNU <tt>ld</tt> linker to fail an assertion when linking
77 components of the libstdc++. It is recommended that you replace the entire
78 binutils package with version 2.15 such that "<tt>ld --version</tt>" responds
80 <pre>GNU ld version 2.15</pre>
82 <pre>GNU ld version 2.15.91 20040725</pre>
85 <!--=========================================================================-->
86 <div class="doc_subsection"><a name="aix">Building under AIX</a></div>
87 <div class="doc_text">
88 <p>If you are building LLVM and the GCC front-end under AIX, do NOT use GNU
89 Binutils. They are not stable under AIX and may produce incorrect and/or
90 invalid code. Instead, use the system assembler and linker.
94 <!-- *********************************************************************** -->
95 <div class="doc_section">
96 <a name="instructions">Instructions</a>
98 <!-- *********************************************************************** -->
100 <div class="doc_text">
103 <li><p>Configure and build the LLVM libraries and tools. There are two ways to
104 do this: either with <i>objdir</i> == <i>srcdir</i> or not. It is recommended
105 that <i>srcdir</i> not be the same as <i>objdir</i>:</p>
107 <li>With <i>objdir</i> != <i>srcdir</i>:<pre>
109 % <i>srcdir</i>/configure --prefix=/some/path/you/can/install/to [options...]
112 <li>With <i>objdir</i> == <i>srcdir</i>:<pre>
114 % ./configure --prefix=/some/path/you/can/install/to [options...]
118 <p>This will build all of the LLVM tools and libraries. The <tt>--prefix</tt>
119 option defaults to /usr/local (per configure standards) but unless you are a
120 system administrator, you probably won't be able to install LLVM there because
121 of permissions. Specify a path into which LLVM can be installed (e.g.
122 <tt>--prefix=/home/user/llvm</tt>).</p>
125 <li><p>Add the directory containing the tools to your PATH.</p>
127 % set path = ( `cd llvm/Debug/bin && pwd` $path )
130 <li><p>Unpack the C/C++ front-end source into cfrontend/src, either by
131 untar'ing an llvm-gcc.tar.gz file or checking out CVS into this
134 <li><p>Make "build" and "install" directories as siblings of the "src" tree.</p>
137 /usr/local/example/cfrontend/src
139 % mkdir build install
140 % set CFEINSTALL = `pwd`/install
144 <li><p>Configure, build, and install the GCC front-end:</p>
147 <b>Linux/x86:</b><br>
148 <b>MacOS X/PowerPC</b> (requires dlcompat library):<br>
154 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
155 --disable-shared --enable-languages=c,c++ --program-prefix=llvm-
156 % gmake all; gmake install
159 <p><b>Cygwin/x86:</b></p>
163 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
164 --disable-shared --enable-languages=c,c++ --disable-c-mbchar \
165 --program-prefix=llvm-
166 % gmake all; gmake install
169 <p><b>Solaris/SPARC:</b></p>
172 For Solaris/SPARC, LLVM only supports the SPARC V9 architecture. Therefore,
173 the configure command line should specify sparcv9, as shown below. Also,
174 note that Solaris has trouble with various wide (multibyte) character
175 functions from C as referenced from C++, so we typically configure with
176 --disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>).
181 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
182 --disable-shared --enable-languages=c,c++ --host=sparcv9-sun-solaris2.8 \
183 --disable-c-mbchar --program-prefix=llvm-
184 % gmake all; gmake install
187 <p><b>Common Problem:</b> You may get error messages regarding the fact
188 that LLVM does not support inline assembly. Here are two common
192 <li><p><b>Fix 1:</b> If you have system header files that include
193 inline assembly, you may have to modify them to remove the inline
194 assembly and install the modified versions in
195 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.</li>
197 <li><b>Fix 2:</b> If you are building the C++ front-end on a CPU we
198 haven't tried yet, you will probably have to edit the appropriate
199 version of atomicity.h under
200 <code>src/libstdc++-v3/config/cpu/<i>name-of-cpu</i>/atomicity.h</code>
201 and apply a patch so that it does not use inline assembly.</li>
204 <p><b>Porting to a new architecture:</b> If you are porting the front-end
205 to a new architecture or compiling in a configuration that we have
206 not tried previously, there are probably several changes you will have to make
207 to the GCC target to get it to work correctly. These include:<p>
210 <li>Often targets include special assembler or linker flags which
211 <tt>gccas</tt>/<tt>gccld</tt> does not understand. In general, these can
212 just be removed.</li>
213 <li>LLVM currently does not support any floating point values other than
214 32-bit and 64-bit IEEE floating point. The primary effect of this is
215 that you may have to map "long double" onto "double".</li>
216 <li>The profiling hooks in GCC do not apply at all to the LLVM front-end.
217 These may need to be disabled.</li>
218 <li>No inline assembly for position independent code. At the LLVM level,
219 everything is position independent.</li>
220 <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>
221 <li>You may have to disable multilib support in your target. Using multilib
222 support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"
223 options to the link line, which do not relate to LLVM and confuse
224 <tt>gccld</tt>. To disable multilibs, delete any
225 <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>
226 <li>Did we mention that we don't support inline assembly? You'll probably
227 have to add some fixinclude hacks to disable it in the system
232 <li><p>Put <tt>$CFEINSTALL/bin</tt> into your <tt>PATH</tt> environment
235 <li>sh: <tt>export PATH=$CFEINSTALL/bin:$PATH</tt></li>
236 <li>csh: <tt>setenv PATH $CFEINSTALL/bin:$PATH</tt></li>
240 <li><p>Go back into the LLVM source tree proper. Rerun configure, using
241 the same options as the last time. This will cause the configuration to now find
242 the newly built llvm-gcc and llvm-g++ executables. </p></li>
244 <li><p>Rebuild your CVS tree. This shouldn't cause the whole thing to be
245 rebuilt, but it should build the runtime libraries. After the tree is
246 built, install the runtime libraries into your GCC front-end build tree.
247 These are the commands you need:</p>
250 % gmake -C runtime install-bytecode
253 <li><p>Optionally, build a symbol table for the newly installed runtime
254 libraries. Although this step is optional, you are strongly encouraged to
255 do this as the symbol tables will make a significant difference in your
256 link times. Use the <tt>llvm-ranlib</tt> tool to do this, as follows:</p>
259 % llvm-ranlib libiberty.a
260 % llvm-ranlib libstdc++.a
261 % llvm-ranlib libsupc++.a
262 % cd $CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm
263 % llvm-ranlib libgcc.a
264 % llvm-ranlib libgcov.a
267 <li><p>Test the newly-installed C frontend by one or more of the
270 <li> running the feature & regression tests via <tt>make check</tt></li>
271 <li> compiling and running a "hello, LLVM" program in C and C++.</li>
272 <li> running the tests found in the <tt>llvm-test</tt> CVS module</li>
277 <!-- *********************************************************************** -->
278 <div class="doc_section">
279 <a name="license">License Information</a>
282 <div class="doc_text">
284 The LLVM GCC frontend is licensed to you under the GNU General Public License
285 and the GNU Lesser General Public License. Please see the files COPYING and
286 COPYING.LIB for more details.
290 The software also has the following additional copyrights:
295 Copyright (c) 2003, 2004 University of Illinois at Urbana-Champaign.
302 University of Illinois at Urbana-Champaign
304 http://llvm.cs.uiuc.edu
306 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
307 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
308 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
309 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
310 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
311 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
315 Hewlett-Packard Company
317 Permission to use, copy, modify, distribute and sell this software
318 and its documentation for any purpose is hereby granted without fee,
319 provided that the above copyright notice appear in all copies and
320 that both that copyright notice and this permission notice appear
321 in supporting documentation. Hewlett-Packard Company makes no
322 representations about the suitability of this software for any
323 purpose. It is provided "as is" without express or implied warranty.
325 Copyright (c) 1996, 1997, 1998, 1999
326 Silicon Graphics Computer Systems, Inc.
328 Permission to use, copy, modify, distribute and sell this software
329 and its documentation for any purpose is hereby granted without fee,
330 provided that the above copyright notice appear in all copies and
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332 in supporting documentation. Silicon Graphics makes no
333 representations about the suitability of this software for any
334 purpose. It is provided "as is" without express or implied warranty.
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