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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++
135 % gmake all; gmake install
138 <p><b>Cygwin/x86:</b></p>
142 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
143 --disable-shared --enable-languages=c,c++ --disable-c-mbchar
144 % gmake all; gmake install
147 <p><b>Solaris/SPARC:</b></p>
150 For Solaris/SPARC, LLVM only supports the SPARC V9 architecture. Therefore,
151 the configure command line should specify sparcv9, as shown below. Also,
152 note that Solaris has trouble with various wide (multibyte) character
153 functions from C as referenced from C++, so we typically configure with
154 --disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>).
159 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
160 --disable-shared --enable-languages=c,c++ --host=sparcv9-sun-solaris2.8 \
162 % gmake all; gmake install
165 <p><b>Common Problem:</b> You may get error messages regarding the fact
166 that LLVM does not support inline assembly. Here are two common
170 <li><p><b>Fix 1:</b> If you have system header files that include
171 inline assembly, you may have to modify them to remove the inline
172 assembly and install the modified versions in
173 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.</li>
175 <li><b>Fix 2:</b> If you are building the C++ front-end on a CPU we
176 haven't tried yet, you will probably have to edit the appropriate
177 version of atomicity.h under
178 <code>src/libstdc++-v3/config/cpu/<i>name-of-cpu</i>/atomicity.h</code>
179 and apply a patch so that it does not use inline assembly.</li>
182 <p><b>Porting to a new architecture:</b> If you are porting the front-end
183 to a new architecture or compiling in a configuration that we have
184 not tried previously, there are probably several changes you will have to make
185 to the GCC target to get it to work correctly. These include:<p>
188 <li>Often targets include special assembler or linker flags which
189 <tt>gccas</tt>/<tt>gccld</tt> does not understand. In general, these can
190 just be removed.</li>
191 <li>LLVM currently does not support any floating point values other than
192 32-bit and 64-bit IEEE floating point. The primary effect of this is
193 that you may have to map "long double" onto "double".</li>
194 <li>The profiling hooks in GCC do not apply at all to the LLVM front-end.
195 These may need to be disabled.</li>
196 <li>No inline assembly for position independent code. At the LLVM level,
197 everything is position independent.</li>
198 <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>
199 <li>You may have to disable multilib support in your target. Using multilib
200 support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"
201 options to the link line, which do not relate to LLVM and confuse
202 <tt>gccld</tt>. To disable multilibs, delete any
203 <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>
204 <li>Did we mention that we don't support inline assembly? You'll probably
205 have to add some fixinclude hacks to disable it in the system
210 <li><p>Go back into the LLVM source tree proper. Rerun configure, using
211 the <code>--with-llvmgccdir=$CFEINSTALL</code> option to specify the path
212 to the newly built GCC front-end.</p></li>
214 <li><p>If you edited header files during the C/C++ front-end build as
215 described in "Fix 1" above, you must now copy those header files from
216 <code>$CFEINSTALL/<i>target-triplet</i>/sys-include</code> to
217 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.
218 (This should be the "include" directory in the same directory as the
219 libgcc.a library, which you can find by running
220 <code>$CFEINSTALL/bin/gcc --print-libgcc-file-name</code>.)</p></li>
222 <li><p>Rebuild your CVS tree. This shouldn't cause the whole thing to be
223 rebuilt, but it should build the runtime libraries. After the tree is
224 built, install the runtime libraries into your GCC front-end build tree.
225 These are the commands you need.</p>
228 % mkdir $CFEINSTALL/lib
229 % gmake -C runtime install-bytecode
232 <li><p>Optionally, build a symbol table for the newly installed runtime
233 libraries. Although this step is optional, you are encouraged to do this as the
234 symbol tables will make a significant difference in your link times. Use
235 the <tt>llvm-ranlib</tt> tool to do this, as follows:</p>
238 % llvm-ranlib libiberty.a
239 % llvm-ranlib libstdc++.a
240 % llvm-ranlib libsupc++.a
241 % cd $CFEINSTALL/lib/<i>target-triplet</i>/3.4-llvm
242 % llvm-ranlib libgcc.a
243 % llvm-ranlib libgcov.a
246 <li><p>Test the newly-installed C frontend by one or more of the
249 <li> compiling and running a "hello, LLVM" program in C and C++.</li>
250 <li> running the regression tests in <tt>llvm/test</tt>
251 <li> running the tests found in the <tt>llvm-test</tt> CVS module</li>
256 <!-- *********************************************************************** -->
257 <div class="doc_section">
258 <a name="license">License Information</a>
261 <div class="doc_text">
263 The LLVM GCC frontend is licensed to you under the GNU General Public License
264 and the GNU Lesser General Public License. Please see the files COPYING and
265 COPYING.LIB for more details.
269 The software also has the following additional copyrights:
274 Copyright (c) 2003, 2004 University of Illinois at Urbana-Champaign.
281 University of Illinois at Urbana-Champaign
283 http://llvm.cs.uiuc.edu
285 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
286 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
287 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
288 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
289 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
290 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
294 Hewlett-Packard Company
296 Permission to use, copy, modify, distribute and sell this software
297 and its documentation for any purpose is hereby granted without fee,
298 provided that the above copyright notice appear in all copies and
299 that both that copyright notice and this permission notice appear
300 in supporting documentation. Hewlett-Packard Company makes no
301 representations about the suitability of this software for any
302 purpose. It is provided "as is" without express or implied warranty.
304 Copyright (c) 1996, 1997, 1998, 1999
305 Silicon Graphics Computer Systems, Inc.
307 Permission to use, copy, modify, distribute and sell this software
308 and its documentation for any purpose is hereby granted without fee,
309 provided that the above copyright notice appear in all copies and
310 that both that copyright notice and this permission notice appear
311 in supporting documentation. Silicon Graphics makes no
312 representations about the suitability of this software for any
313 purpose. It is provided "as is" without express or implied warranty.
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