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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>
51 <p>We welcome patches to help make this process simpler.</p>
54 <!--=========================================================================-->
55 <div class="doc_subsection">
56 <a name="cygwin">Building under Cygwin</a>
58 <!--=========================================================================-->
60 <div class="doc_text">
61 <p>If you are building LLVM and the GCC front-end under Cygwin, please note that
62 the LLVM and GCC makefiles do not correctly handle spaces in paths. To deal
63 with this issue, make sure that your LLVM and GCC source and build trees are
64 located in a top-level directory (like <tt>/cygdrive/c/llvm</tt> and
65 <tt>/cygdrive/c/llvm-cfrontend</tt>), not in a directory that contains a space
66 (which includes your "home directory", because it lives under the "Documents
67 and Settings" directory). We welcome patches to fix this issue.
69 <p>It has been found that the GCC 3.3.3 compiler provided with recent Cygwin
70 versions is incapable of compiling the LLVM CFE correctly. If your Cygwin
71 installation includes GCC 3.3.3 we <i>strongly</i> recommend that you download
72 GCC 3.4.3, build it separately, and use it for compiling LLVM CFE. This has been
73 shown to work correctly.</p>
74 <p>Some versions of Cygwin utilize an experimental version of GNU binutils that
75 will cause the GNU <tt>ld</tt> linker to fail an assertion when linking
76 components of the libstdc++. It is recommended that you replace the entire
77 binutils package with version 2.15 such that "<tt>ld --version</tt>" responds
79 <pre>GNU ld version 2.15</pre>
81 <pre>GNU ld version 2.15.91 20040725</pre>
84 <!--=========================================================================-->
85 <div class="doc_subsection">
86 <a name="aix">Building under AIX</a>
88 <!--=========================================================================-->
90 <div class="doc_text">
91 <p>If you are building LLVM and the GCC front-end under AIX, do NOT use GNU
92 Binutils. They are not stable under AIX and may produce incorrect and/or
93 invalid code. Instead, use the system assembler and linker.
97 <!-- *********************************************************************** -->
98 <div class="doc_section">
99 <a name="instructions">Instructions</a>
101 <!-- *********************************************************************** -->
103 <div class="doc_text">
106 <li><p>Configure and build the LLVM libraries and tools using:</p>
109 % ./configure --prefix=/some/path/you/can/install/to [options...]
112 <p>This will build all of the LLVM tools and libraries. The <tt>--prefix</tt>
113 option defaults to /usr/local (per configure standards) but unless you are a
114 system administrator, you probably won't be able to install LLVM there because
115 of permissions. Specify a path into which LLVM can be installed (e.g.
116 <tt>--prefix=/home/user/llvm</tt>).</p>
119 <li><p>Add the directory containing the tools to your PATH.</p>
121 % set path = ( `cd llvm/Debug/bin && pwd` $path )
124 <li><p>Unpack the C/C++ front-end source into cfrontend/src.</p></li>
126 <li><p>Make "build" and "install" directories as siblings of the "src" tree.</p>
129 /usr/local/example/cfrontend/src
131 % mkdir build install
132 % set CFEINSTALL = `pwd`/install
136 <li><p>Configure, build, and install the GCC front-end:</p>
139 <b>Linux/x86:</b><br>
140 <b>MacOS X/PowerPC</b> (requires dlcompat library):<br>
146 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
147 --disable-shared --enable-languages=c,c++ --program-prefix=llvm-
148 % gmake all; gmake install
151 <p><b>Cygwin/x86:</b></p>
155 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
156 --disable-shared --enable-languages=c,c++ --disable-c-mbchar \
157 --program-prefix=llvm-
158 % gmake all; gmake install
161 <p><b>Solaris/SPARC:</b></p>
164 For Solaris/SPARC, LLVM only supports the SPARC V9 architecture. Therefore,
165 the configure command line should specify sparcv9, as shown below. Also,
166 note that Solaris has trouble with various wide (multibyte) character
167 functions from C as referenced from C++, so we typically configure with
168 --disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>).
173 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
174 --disable-shared --enable-languages=c,c++ --host=sparcv9-sun-solaris2.8 \
175 --disable-c-mbchar --program-prefix=llvm-
176 % gmake all; gmake install
179 <p><b>Common Problem:</b> You may get error messages regarding the fact
180 that LLVM does not support inline assembly. Here are two common
184 <li><p><b>Fix 1:</b> If you have system header files that include
185 inline assembly, you may have to modify them to remove the inline
186 assembly and install the modified versions in
187 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.</li>
189 <li><b>Fix 2:</b> If you are building the C++ front-end on a CPU we
190 haven't tried yet, you will probably have to edit the appropriate
191 version of atomicity.h under
192 <code>src/libstdc++-v3/config/cpu/<i>name-of-cpu</i>/atomicity.h</code>
193 and apply a patch so that it does not use inline assembly.</li>
196 <p><b>Porting to a new architecture:</b> If you are porting the front-end
197 to a new architecture or compiling in a configuration that we have
198 not tried previously, there are probably several changes you will have to make
199 to the GCC target to get it to work correctly. These include:<p>
202 <li>Often targets include special assembler or linker flags which
203 <tt>gccas</tt>/<tt>gccld</tt> does not understand. In general, these can
204 just be removed.</li>
205 <li>LLVM currently does not support any floating point values other than
206 32-bit and 64-bit IEEE floating point. The primary effect of this is
207 that you may have to map "long double" onto "double".</li>
208 <li>The profiling hooks in GCC do not apply at all to the LLVM front-end.
209 These may need to be disabled.</li>
210 <li>No inline assembly for position independent code. At the LLVM level,
211 everything is position independent.</li>
212 <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>
213 <li>You may have to disable multilib support in your target. Using multilib
214 support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"
215 options to the link line, which do not relate to LLVM and confuse
216 <tt>gccld</tt>. To disable multilibs, delete any
217 <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>
218 <li>Did we mention that we don't support inline assembly? You'll probably
219 have to add some fixinclude hacks to disable it in the system
224 <li><p>Put <tt>$CFEINSTALL/bin</tt> into your <tt>PATH</tt> environment
227 <li>sh: <tt>export PATH=$CFEINSTALL/bin:$PATH</tt></li>
228 <li>csh: <tt>setenv PATH $CFEINSTALL/bin:$PATH</tt></li>
232 <li><p>Go back into the LLVM source tree proper. Rerun configure, using
233 the same options as the last time. This will cause the configuration to now find
234 the newly built llvm-gcc and llvm-g++ executables. </p></li>
236 <li><p>Rebuild your CVS tree. This shouldn't cause the whole thing to be
237 rebuilt, but it should build the runtime libraries. After the tree is
238 built, install the runtime libraries into your GCC front-end build tree.
239 These are the commands you need.</p>
242 % gmake -C runtime install-bytecode
245 <li><p>Optionally, build a symbol table for the newly installed runtime
246 libraries. Although this step is optional, you are strongly encouraged to
247 do this as the symbol tables will make a significant difference in your
248 link times. Use the <tt>llvm-ranlib</tt> tool to do this, as follows:</p>
251 % llvm-ranlib libiberty.a
252 % llvm-ranlib libstdc++.a
253 % llvm-ranlib libsupc++.a
254 % cd $CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm
255 % llvm-ranlib libgcc.a
256 % llvm-ranlib libgcov.a
259 <li><p>Test the newly-installed C frontend by one or more of the
262 <li> running the feature & regression tests via <tt>make check</tt></li>
263 <li> compiling and running a "hello, LLVM" program in C and C++.</li>
264 <li> running the tests found in the <tt>llvm-test</tt> CVS module</li>
269 <!-- *********************************************************************** -->
270 <div class="doc_section">
271 <a name="license">License Information</a>
274 <div class="doc_text">
276 The LLVM GCC frontend is licensed to you under the GNU General Public License
277 and the GNU Lesser General Public License. Please see the files COPYING and
278 COPYING.LIB for more details.
282 The software also has the following additional copyrights:
287 Copyright (c) 2003, 2004 University of Illinois at Urbana-Champaign.
294 University of Illinois at Urbana-Champaign
296 http://llvm.cs.uiuc.edu
298 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
299 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
300 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
301 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
302 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
303 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
307 Hewlett-Packard Company
309 Permission to use, copy, modify, distribute and sell this software
310 and its documentation for any purpose is hereby granted without fee,
311 provided that the above copyright notice appear in all copies and
312 that both that copyright notice and this permission notice appear
313 in supporting documentation. Hewlett-Packard Company makes no
314 representations about the suitability of this software for any
315 purpose. It is provided "as is" without express or implied warranty.
317 Copyright (c) 1996, 1997, 1998, 1999
318 Silicon Graphics Computer Systems, Inc.
320 Permission to use, copy, modify, distribute and sell this software
321 and its documentation for any purpose is hereby granted without fee,
322 provided that the above copyright notice appear in all copies and
323 that both that copyright notice and this permission notice appear
324 in supporting documentation. Silicon Graphics makes no
325 representations about the suitability of this software for any
326 purpose. It is provided "as is" without express or implied warranty.
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