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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.
71 <!--=========================================================================-->
72 <div class="doc_subsection">
73 <a name="aix">Building under AIX</a>
75 <!--=========================================================================-->
77 <div class="doc_text">
78 <p>If you are building LLVM and the GCC front-end under AIX, do NOT use GNU
79 Binutils. They are not stable under AIX and may produce incorrect and/or
80 invalid code. Instead, use the system assembler and linker.
84 <!-- *********************************************************************** -->
85 <div class="doc_section">
86 <a name="instructions">Instructions</a>
88 <!-- *********************************************************************** -->
90 <div class="doc_text">
93 <li><p>Configure and build the LLVM libraries and tools using:</p>
96 % ./configure --prefix=/some/path/you/can/install/to [options...]
99 <p>This will build all of the LLVM tools and libraries. The <tt>--prefix</tt>
100 option defaults to /usr/local (per configure standards) but unless you are a
101 system administrator, you probably won't be able to install LLVM there because
102 of permissions. Specify a path into which LLVM can be installed (e.g.
103 <tt>--prefix=/home/user/llvm</tt>).</p>
106 <li><p>Add the directory containing the tools to your PATH.</p>
108 % set path = ( `cd llvm/Debug/bin && pwd` $path )
111 <li><p>Unpack the C/C++ front-end source into cfrontend/src.</p></li>
113 <li><p>Make "build" and "install" directories as siblings of the "src" tree.</p>
116 /usr/local/example/cfrontend/src
118 % mkdir build install
119 % set CFEINSTALL = `pwd`/install
123 <li><p>Configure, build, and install the GCC front-end:</p>
126 <b>Linux/x86:</b><br>
127 <b>MacOS X/PowerPC</b> (requires dlcompat library):<br>
133 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
134 --disable-shared --enable-languages=c,c++ --program-prefix=llvm-
135 % gmake all; gmake install
138 <p><b>Cygwin/x86:</b></p>
142 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
143 --disable-shared --enable-languages=c,c++ --disable-c-mbchar \
144 --program-prefix=llvm-
145 % gmake all; gmake install
148 <p><b>Solaris/SPARC:</b></p>
151 For Solaris/SPARC, LLVM only supports the SPARC V9 architecture. Therefore,
152 the configure command line should specify sparcv9, as shown below. Also,
153 note that Solaris has trouble with various wide (multibyte) character
154 functions from C as referenced from C++, so we typically configure with
155 --disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>).
160 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
161 --disable-shared --enable-languages=c,c++ --host=sparcv9-sun-solaris2.8 \
162 --disable-c-mbchar --program-prefix=llvm-
163 % gmake all; gmake install
166 <p><b>Common Problem:</b> You may get error messages regarding the fact
167 that LLVM does not support inline assembly. Here are two common
171 <li><p><b>Fix 1:</b> If you have system header files that include
172 inline assembly, you may have to modify them to remove the inline
173 assembly and install the modified versions in
174 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.</li>
176 <li><b>Fix 2:</b> If you are building the C++ front-end on a CPU we
177 haven't tried yet, you will probably have to edit the appropriate
178 version of atomicity.h under
179 <code>src/libstdc++-v3/config/cpu/<i>name-of-cpu</i>/atomicity.h</code>
180 and apply a patch so that it does not use inline assembly.</li>
183 <p><b>Porting to a new architecture:</b> If you are porting the front-end
184 to a new architecture or compiling in a configuration that we have
185 not tried previously, there are probably several changes you will have to make
186 to the GCC target to get it to work correctly. These include:<p>
189 <li>Often targets include special assembler or linker flags which
190 <tt>gccas</tt>/<tt>gccld</tt> does not understand. In general, these can
191 just be removed.</li>
192 <li>LLVM currently does not support any floating point values other than
193 32-bit and 64-bit IEEE floating point. The primary effect of this is
194 that you may have to map "long double" onto "double".</li>
195 <li>The profiling hooks in GCC do not apply at all to the LLVM front-end.
196 These may need to be disabled.</li>
197 <li>No inline assembly for position independent code. At the LLVM level,
198 everything is position independent.</li>
199 <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>
200 <li>You may have to disable multilib support in your target. Using multilib
201 support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"
202 options to the link line, which do not relate to LLVM and confuse
203 <tt>gccld</tt>. To disable multilibs, delete any
204 <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>
205 <li>Did we mention that we don't support inline assembly? You'll probably
206 have to add some fixinclude hacks to disable it in the system
211 <li><p>Put <tt>$CFEINSTALL/bin</tt> into your <tt>PATH</tt> environment
214 <li>sh: <tt>export PATH=$CFEINSTALL/bin:$PATH</tt></li>
215 <li>csh: <tt>setenv PATH $CFEINSTALL/bin:$PATH</tt></li>
216 <li>win: <tt>set PATH=$CFEINSTALL/bin;$PATH</tt></li>
220 <li><p>Go back into the LLVM source tree proper. Rerun configure, using
221 the same options as the last time. This will cause the configuration to now find
222 the newly built llvm-gcc and llvm-g++ executables. </p></li>
224 <li><p>If you edited header files during the C/C++ front-end build as
225 described in "Fix 1" above, you must now copy those header files from
226 <code>$CFEINSTALL/<i>target-triplet</i>/sys-include</code> to
227 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.
228 (This should be the "include" directory in the same directory as the
229 libgcc.a library, which you can find by running
230 <code>$CFEINSTALL/bin/llvm-gcc --print-libgcc-file-name</code>.)</p></li>
232 <li><p>Rebuild your CVS tree. This shouldn't cause the whole thing to be
233 rebuilt, but it should build the runtime libraries. After the tree is
234 built, install the runtime libraries into your GCC front-end build tree.
235 These are the commands you need.</p>
238 % mkdir $CFEINSTALL/lib
239 % gmake -C runtime install-bytecode
242 <li><p>Optionally, build a symbol table for the newly installed runtime
243 libraries. Although this step is optional, you are strongly encouraged to
244 do this as the symbol tables will make a significant difference in your
245 link times. Use the <tt>llvm-ranlib</tt> tool to do this, as follows:</p>
248 % llvm-ranlib libiberty.a
249 % llvm-ranlib libstdc++.a
250 % llvm-ranlib libsupc++.a
251 % cd $CFEINSTALL/lib/<i>target-triplet</i>/3.4-llvm
252 % llvm-ranlib libgcc.a
253 % llvm-ranlib libgcov.a
256 <li><p>Test the newly-installed C frontend by one or more of the
259 <li> running the feature & regression tests via <tt>make check</tt></li>
260 <li> compiling and running a "hello, LLVM" program in C and C++.</li>
261 <li> running the tests found in the <tt>llvm-test</tt> CVS module</li>
266 <!-- *********************************************************************** -->
267 <div class="doc_section">
268 <a name="license">License Information</a>
271 <div class="doc_text">
273 The LLVM GCC frontend is licensed to you under the GNU General Public License
274 and the GNU Lesser General Public License. Please see the files COPYING and
275 COPYING.LIB for more details.
279 The software also has the following additional copyrights:
284 Copyright (c) 2003, 2004 University of Illinois at Urbana-Champaign.
291 University of Illinois at Urbana-Champaign
293 http://llvm.cs.uiuc.edu
295 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
296 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
297 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
298 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
299 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
300 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
304 Hewlett-Packard Company
306 Permission to use, copy, modify, distribute and sell this software
307 and its documentation for any purpose is hereby granted without fee,
308 provided that the above copyright notice appear in all copies and
309 that both that copyright notice and this permission notice appear
310 in supporting documentation. Hewlett-Packard Company makes no
311 representations about the suitability of this software for any
312 purpose. It is provided "as is" without express or implied warranty.
314 Copyright (c) 1996, 1997, 1998, 1999
315 Silicon Graphics Computer Systems, Inc.
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. Silicon Graphics makes no
322 representations about the suitability of this software for any
323 purpose. It is provided "as is" without express or implied warranty.
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