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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
105 <i>objdir</i> != <i>srcdir</i>. It is recommended
106 that <i>srcdir</i> not be the same as <i>objdir</i>:</p>
108 <li>With <i>objdir</i> != <i>srcdir</i>:<pre>
110 % <i>srcdir</i>/configure --prefix=/some/path/you/can/install/to [options...]
113 <li>With <i>objdir</i> == <i>srcdir</i>:<pre>
115 % ./configure --prefix=/some/path/you/can/install/to [options...]
119 <p>This will build all of the LLVM tools and libraries. The <tt>--prefix</tt>
120 option defaults to /usr/local (per configure standards) but unless you are a
121 system administrator, you probably won't be able to install LLVM there because
122 of permissions. Specify a path into which LLVM can be installed (e.g.
123 <tt>--prefix=/home/user/llvm</tt>).</p>
126 <li><p>Add the directory containing the tools to your PATH.</p>
128 % set path = ( `cd llvm/Debug/bin && pwd` $path )
131 <li><p>Unpack the C/C++ front-end source into cfrontend/src, either by
132 untar'ing an llvm-gcc.tar.gz file or checking out CVS into this
135 <li><p>Make "build" and "install" directories as siblings of the "src" tree:</p>
138 /usr/local/example/cfrontend/src
140 % mkdir build install
141 % set CFEINSTALL = `pwd`/install
145 <li><p>Configure, build, and install the GCC front-end:</p>
148 <b>Linux/x86:</b><br>
149 <b>MacOS X/PowerPC</b> (requires dlcompat library):<br>
155 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
156 --disable-shared --enable-languages=c,c++ --program-prefix=llvm-
157 % gmake all; gmake install
160 <p><b>Cygwin/x86:</b></p>
164 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
165 --disable-shared --enable-languages=c,c++ --disable-c-mbchar \
166 --program-prefix=llvm-
167 % gmake all; gmake install
170 <p><b>Solaris/SPARC:</b></p>
173 For Solaris/SPARC, LLVM only supports the SPARC V9 architecture. Therefore,
174 the configure command line should specify sparcv9, as shown below. Also,
175 note that Solaris has trouble with various wide (multibyte) character
176 functions from C as referenced from C++, so we typically configure with
177 --disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>).
182 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
183 --disable-shared --enable-languages=c,c++ --host=sparcv9-sun-solaris2.8 \
184 --disable-c-mbchar --program-prefix=llvm-
185 % gmake all; gmake install
188 <p><b>Common Problem:</b> You may get error messages regarding the fact
189 that LLVM does not support inline assembly. Here are two common
193 <li><p><b>Fix 1:</b> If you have system header files that include
194 inline assembly, you may have to modify them to remove the inline
195 assembly and install the modified versions in
196 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.</li>
198 <li><b>Fix 2:</b> If you are building the C++ front-end on a CPU we
199 haven't tried yet, you will probably have to edit the appropriate
200 version of atomicity.h under
201 <code>src/libstdc++-v3/config/cpu/<i>name-of-cpu</i>/atomicity.h</code>
202 and apply a patch so that it does not use inline assembly.</li>
205 <p><b>Porting to a new architecture:</b> If you are porting the front-end
206 to a new architecture or compiling in a configuration that we have
207 not tried previously, there are probably several changes you will have to make
208 to the GCC target to get it to work correctly. These include:<p>
211 <li>Often targets include special assembler or linker flags which
212 <tt>gccas</tt>/<tt>gccld</tt> does not understand. In general, these can
213 just be removed.</li>
214 <li>LLVM currently does not support any floating point values other than
215 32-bit and 64-bit IEEE floating point. The primary effect of this is
216 that you may have to map "long double" onto "double".</li>
217 <li>The profiling hooks in GCC do not apply at all to the LLVM front-end.
218 These may need to be disabled.</li>
219 <li>No inline assembly for position independent code. At the LLVM level,
220 everything is position independent.</li>
221 <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>
222 <li>You may have to disable multilib support in your target. Using multilib
223 support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"
224 options to the link line, which do not relate to LLVM and confuse
225 <tt>gccld</tt>. To disable multilibs, delete any
226 <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>
227 <li>Did we mention that we don't support inline assembly? You'll probably
228 have to add some fixinclude hacks to disable it in the system
233 <li><p>Put <tt>$CFEINSTALL/bin</tt> into your <tt>PATH</tt> environment
236 <li>sh: <tt>export PATH=$CFEINSTALL/bin:$PATH</tt></li>
237 <li>csh: <tt>setenv PATH $CFEINSTALL/bin:$PATH</tt></li>
241 <li><p>Go back into the LLVM source tree proper. Rerun configure, using
242 the same options as the last time. This will cause the configuration to now find
243 the newly built llvm-gcc and llvm-g++ executables. </p></li>
245 <li><p>Rebuild your CVS tree. This shouldn't cause the whole thing to be
246 rebuilt, but it should build the runtime libraries. After the tree is
247 built, install the runtime libraries into your GCC front-end build tree.
248 These are the commands you need:</p>
251 % gmake -C runtime install-bytecode
254 <li><p>Optionally, build a symbol table for the newly installed runtime
255 libraries. Although this step is optional, you are strongly encouraged to
256 do this as the symbol tables will make a significant difference in your
257 link times. Use the <tt>llvm-ranlib</tt> tool to do this, as follows:</p>
260 % llvm-ranlib libiberty.a
261 % llvm-ranlib libstdc++.a
262 % llvm-ranlib libsupc++.a
263 % cd $CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm
264 % llvm-ranlib libgcc.a
265 % llvm-ranlib libgcov.a
268 <li><p>Test the newly-installed C frontend by one or more of the
271 <li> running the feature & regression tests via <tt>make check</tt></li>
272 <li> compiling and running a "hello, LLVM" program in C and C++.</li>
273 <li> running the tests found in the <tt>llvm-test</tt> CVS module</li>
278 <!-- *********************************************************************** -->
279 <div class="doc_section">
280 <a name="license">License Information</a>
283 <div class="doc_text">
285 The LLVM GCC frontend is licensed to you under the GNU General Public License
286 and the GNU Lesser General Public License. Please see the files COPYING and
287 COPYING.LIB for more details.
291 The software also has the following additional copyrights:
296 Copyright (c) 2003, 2004, 2005 University of Illinois at Urbana-Champaign.
303 University of Illinois at Urbana-Champaign
305 http://llvm.cs.uiuc.edu
307 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
308 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
309 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
310 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
311 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
312 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
316 Hewlett-Packard Company
318 Permission to use, copy, modify, distribute and sell this software
319 and its documentation for any purpose is hereby granted without fee,
320 provided that the above copyright notice appear in all copies and
321 that both that copyright notice and this permission notice appear
322 in supporting documentation. Hewlett-Packard Company makes no
323 representations about the suitability of this software for any
324 purpose. It is provided "as is" without express or implied warranty.
326 Copyright (c) 1996, 1997, 1998, 1999
327 Silicon Graphics Computer Systems, Inc.
329 Permission to use, copy, modify, distribute and sell this software
330 and its documentation for any purpose is hereby granted without fee,
331 provided that the above copyright notice appear in all copies and
332 that both that copyright notice and this permission notice appear
333 in supporting documentation. Silicon Graphics makes no
334 representations about the suitability of this software for any
335 purpose. It is provided "as is" without express or implied warranty.
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