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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"><a name="aix">Building under AIX</a></div>
86 <div class="doc_text">
87 <p>If you are building LLVM and the GCC front-end under AIX, do NOT use GNU
88 Binutils. They are not stable under AIX and may produce incorrect and/or
89 invalid code. Instead, use the system assembler and linker.
93 <!-- *********************************************************************** -->
94 <div class="doc_section">
95 <a name="instructions">Instructions</a>
97 <!-- *********************************************************************** -->
99 <div class="doc_text">
102 <li><p>Configure and build the LLVM libraries and tools. There are two ways to
103 do this: either with <i>objdir</i> == <i>srcdir</i> or not. It is recommended
104 that <i>srcdir</i> not be the same as <i>objdir</i>:</p>
106 <li>With <i>objdir</i> != <i>srcdir</i>:<pre>
108 % <i>srcdir</i>/configure --prefix=/some/path/you/can/install/to [options...]
111 <li>With <i>objdir</i> == <i>srcdir</i>:<pre>
113 % ./configure --prefix=/some/path/you/can/install/to [options...]
117 <p>This will build all of the LLVM tools and libraries. The <tt>--prefix</tt>
118 option defaults to /usr/local (per configure standards) but unless you are a
119 system administrator, you probably won't be able to install LLVM there because
120 of permissions. Specify a path into which LLVM can be installed (e.g.
121 <tt>--prefix=/home/user/llvm</tt>).</p>
124 <li><p>Add the directory containing the tools to your PATH.</p>
126 % set path = ( `cd llvm/Debug/bin && pwd` $path )
129 <li><p>Unpack the C/C++ front-end source into cfrontend/src, either by
130 untar'ing an llvm-gcc.tar.gz file or checking out CVS into this
133 <li><p>Make "build" and "install" directories as siblings of the "src" tree.</p>
136 /usr/local/example/cfrontend/src
138 % mkdir build install
139 % set CFEINSTALL = `pwd`/install
143 <li><p>Configure, build, and install the GCC front-end:</p>
146 <b>Linux/x86:</b><br>
147 <b>MacOS X/PowerPC</b> (requires dlcompat library):<br>
153 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
154 --disable-shared --enable-languages=c,c++ --program-prefix=llvm-
155 % gmake all; gmake install
158 <p><b>Cygwin/x86:</b></p>
162 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
163 --disable-shared --enable-languages=c,c++ --disable-c-mbchar \
164 --program-prefix=llvm-
165 % gmake all; gmake install
168 <p><b>Solaris/SPARC:</b></p>
171 For Solaris/SPARC, LLVM only supports the SPARC V9 architecture. Therefore,
172 the configure command line should specify sparcv9, as shown below. Also,
173 note that Solaris has trouble with various wide (multibyte) character
174 functions from C as referenced from C++, so we typically configure with
175 --disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>).
180 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
181 --disable-shared --enable-languages=c,c++ --host=sparcv9-sun-solaris2.8 \
182 --disable-c-mbchar --program-prefix=llvm-
183 % gmake all; gmake install
186 <p><b>Common Problem:</b> You may get error messages regarding the fact
187 that LLVM does not support inline assembly. Here are two common
191 <li><p><b>Fix 1:</b> If you have system header files that include
192 inline assembly, you may have to modify them to remove the inline
193 assembly and install the modified versions in
194 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.</li>
196 <li><b>Fix 2:</b> If you are building the C++ front-end on a CPU we
197 haven't tried yet, you will probably have to edit the appropriate
198 version of atomicity.h under
199 <code>src/libstdc++-v3/config/cpu/<i>name-of-cpu</i>/atomicity.h</code>
200 and apply a patch so that it does not use inline assembly.</li>
203 <p><b>Porting to a new architecture:</b> If you are porting the front-end
204 to a new architecture or compiling in a configuration that we have
205 not tried previously, there are probably several changes you will have to make
206 to the GCC target to get it to work correctly. These include:<p>
209 <li>Often targets include special assembler or linker flags which
210 <tt>gccas</tt>/<tt>gccld</tt> does not understand. In general, these can
211 just be removed.</li>
212 <li>LLVM currently does not support any floating point values other than
213 32-bit and 64-bit IEEE floating point. The primary effect of this is
214 that you may have to map "long double" onto "double".</li>
215 <li>The profiling hooks in GCC do not apply at all to the LLVM front-end.
216 These may need to be disabled.</li>
217 <li>No inline assembly for position independent code. At the LLVM level,
218 everything is position independent.</li>
219 <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>
220 <li>You may have to disable multilib support in your target. Using multilib
221 support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"
222 options to the link line, which do not relate to LLVM and confuse
223 <tt>gccld</tt>. To disable multilibs, delete any
224 <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>
225 <li>Did we mention that we don't support inline assembly? You'll probably
226 have to add some fixinclude hacks to disable it in the system
231 <li><p>Put <tt>$CFEINSTALL/bin</tt> into your <tt>PATH</tt> environment
234 <li>sh: <tt>export PATH=$CFEINSTALL/bin:$PATH</tt></li>
235 <li>csh: <tt>setenv PATH $CFEINSTALL/bin:$PATH</tt></li>
239 <li><p>Go back into the LLVM source tree proper. Rerun configure, using
240 the same options as the last time. This will cause the configuration to now find
241 the newly built llvm-gcc and llvm-g++ executables. </p></li>
243 <li><p>Rebuild your CVS tree. This shouldn't cause the whole thing to be
244 rebuilt, but it should build the runtime libraries. After the tree is
245 built, install the runtime libraries into your GCC front-end build tree.
246 These are the commands you need.</p>
249 % gmake -C runtime install-bytecode
252 <li><p>Optionally, build a symbol table for the newly installed runtime
253 libraries. Although this step is optional, you are strongly encouraged to
254 do this as the symbol tables will make a significant difference in your
255 link times. Use the <tt>llvm-ranlib</tt> tool to do this, as follows:</p>
258 % llvm-ranlib libiberty.a
259 % llvm-ranlib libstdc++.a
260 % llvm-ranlib libsupc++.a
261 % cd $CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm
262 % llvm-ranlib libgcc.a
263 % llvm-ranlib libgcov.a
266 <li><p>Test the newly-installed C frontend by one or more of the
269 <li> running the feature & regression tests via <tt>make check</tt></li>
270 <li> compiling and running a "hello, LLVM" program in C and C++.</li>
271 <li> running the tests found in the <tt>llvm-test</tt> CVS module</li>
276 <!-- *********************************************************************** -->
277 <div class="doc_section">
278 <a name="license">License Information</a>
281 <div class="doc_text">
283 The LLVM GCC frontend is licensed to you under the GNU General Public License
284 and the GNU Lesser General Public License. Please see the files COPYING and
285 COPYING.LIB for more details.
289 The software also has the following additional copyrights:
294 Copyright (c) 2003, 2004 University of Illinois at Urbana-Champaign.
301 University of Illinois at Urbana-Champaign
303 http://llvm.cs.uiuc.edu
305 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
306 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
307 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
308 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
309 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
310 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
314 Hewlett-Packard Company
316 Permission to use, copy, modify, distribute and sell this software
317 and its documentation for any purpose is hereby granted without fee,
318 provided that the above copyright notice appear in all copies and
319 that both that copyright notice and this permission notice appear
320 in supporting documentation. Hewlett-Packard Company makes no
321 representations about the suitability of this software for any
322 purpose. It is provided "as is" without express or implied warranty.
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325 Silicon Graphics Computer Systems, Inc.
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328 and its documentation for any purpose is hereby granted without fee,
329 provided that the above copyright notice appear in all copies and
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332 representations about the suitability of this software for any
333 purpose. It is provided "as is" without express or implied warranty.
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