1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
6 <link rel="stylesheet" href="llvm.css" type="text/css" media="screen">
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>
17 <li><a href="#instructions">Instructions</a>
18 <li><a href="#license">License Information</a>
21 <div class="doc_author">
22 <p>Written by Brian R. Gaeke</p>
25 <!-- *********************************************************************** -->
26 <div class="doc_section">
27 <a name="cautionarynote">A Cautionary Note</a>
29 <!-- *********************************************************************** -->
31 <div class="doc_text">
32 <p>This document is intended to explain the process of building the
33 LLVM C/C++ front-end, based on GCC 3.4, from its source code. You
34 would have to do this, for example, if you are porting LLVM to a new
35 architecture or operating system.</p>
37 <p><b>NOTE:</b> This is currently a somewhat fragile, error-prone
38 process, and you should <b>only</b> try to do it if:</p>
41 <li>you really, really, really can't use the binaries we distribute</li>
42 <li>you need GCC to fix some of the header files on your system</li>
43 <li>you are an elite GCC hacker.</li>
46 <p>We welcome patches to help make this process simpler.</p>
49 <!-- *********************************************************************** -->
50 <div class="doc_section">
51 <a name="instructions">Instructions</a>
53 <!-- *********************************************************************** -->
55 <div class="doc_text">
58 <li><p>Configure and build the LLVM libraries and tools using:</p>
61 % ./configure [options...]
64 <p>The use of the non-default target "tools-only" means that the
65 LLVM tools and libraries will build, and the binaries will be
66 deposited in llvm/tools/Debug, but the runtime (bytecode)
67 libraries will not build.</p></li>
69 <li><p>Add the directory containing the tools to your PATH.</p>
71 % set path = ( `cd llvm/tools/Debug && pwd` $path )
74 <li><p>Unpack the C/C++ front-end source into cfrontend/src.</p></li>
76 <li><p>Edit src/configure. Change the first line (starting w/ #!) to
77 contain the correct full pathname of sh.</p></li>
79 <li><p>Make "build" and "install" directories as siblings of the "src"
83 /usr/local/example/cfrontend/src
86 % set CFEINSTALL = `pwd`/install
89 <li><p>Configure, build, and install the C front-end:</p>
94 <b>MacOS X/PowerPC:</b>
99 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls --disable-shared \
100 --enable-languages=c,c++
102 % setenv LLVM_LIB_SEARCH_PATH `pwd`/gcc
103 % gmake all; gmake install
107 <b>Solaris/SPARC:</b>
111 For Solaris/SPARC, LLVM only supports the SPARC V9. Therefore, the
112 configure command line should specify sparcv9, as shown below. Also,
113 note that Solaris has trouble with various wide (multibyte) character
114 functions from C as referenced from C++, so we typically configure with
115 --disable-c-mbchar (cf. <a href="http://llvm.cs.uiuc.edu/PR206">Bug 206</a>).
120 % ../src/configure --prefix=$CFEINSTALL --disable-threads --disable-nls \
121 --disable-shared --enable-languages=c,c++ --host=sparcv9-sun-solaris2.8 \
124 % setenv LLVM_LIB_SEARCH_PATH `pwd`/gcc
125 % gmake all; gmake install
128 <p><b>Common Problem:</b> You may get error messages regarding the fact
129 that LLVM does not support inline assembly. Here are two common
133 <li><p><b>Fix 1:</b> If you have system header files that include
134 inline assembly, you may have to modify them to remove the inline
135 assembly, and install the modified versions in
136 <code>$CFEINSTALL/<i>target-triplet</i>/sys-include</code>.</li>
138 <li><b>Fix 2:</b> If you are building the C++ front-end on a CPU we
139 haven't tried yet, you will probably have to edit the appropriate
140 version of atomicity.h under
141 <code>src/libstdc++-v3/config/cpu/<i>name-of-cpu</i>/atomicity.h</code>
142 and apply a patch so that it does not use inline assembly.</li>
145 <p><b>Porting to a new architecture:</b> If you are porting the new front-end
146 to a new architecture, or compiling in a different configuration that we have
147 previously, there are probably several changes you will have to make to the GCC
148 target to get it to work correctly. These include:<p>
151 <li>Often targets include special or assembler linker flags which
152 <tt>gccas</tt>/<tt>gccld</tt> does not understand. In general, these can
153 just be removed.</li>
154 <li>LLVM currently does not support any floating point values other than
155 32-bit and 64-bit IEEE floating point. The primary effect of this is
156 that you may have to map "long double" onto "double".</li>
157 <li>The profiling hooks in GCC do not apply at all to the LLVM front-end.
158 These may need to be disabled.</li>
159 <li>No inline assembly for position independent code. At the LLVM level,
160 everything is position independent.</li>
161 <li>We handle <tt>.init</tt> and <tt>.fini</tt> differently.</li>
162 <li>You may have to disable multilib support in your target. Using multilib
163 support causes the GCC compiler driver to add a lot of "<tt>-L</tt>"
164 options to the link line, which do not relate to LLVM and confuse
165 <tt>gccld</tt>. To disable multilibs, delete any
166 <tt>MULTILIB_OPTIONS</tt> lines from your target files.</li>
167 <li>Did we mention that we don't support inline assembly? You'll probably
168 have to add some fixinclude hacks to disable it in the system
173 <li><p>Go back into the LLVM source tree proper. Edit Makefile.config
174 to redefine <code>LLVMGCCDIR</code> to the full pathname of the
175 <code>$CFEINSTALL</code> directory, which is the directory you just
176 installed the C front-end into. (The ./configure script is likely to
177 have set this to a directory which does not exist on your system.)</p></li>
179 <li><p>If you edited header files during the C/C++ front-end build as
180 described in "Fix 1" above, you must now copy those header files from
181 <code>$CFEINSTALL/<i>target-triplet</i>/sys-include</code> to
182 <code>$CFEINSTALL/lib/gcc/<i>target-triplet</i>/3.4-llvm/include</code>.
183 (This should be the "include" directory in the same directory as the
184 libgcc.a library, which you can find by running
185 <code>$CFEINSTALL/bin/gcc --print-libgcc-file-name</code>.)</p></li>
187 <li><p>Build and install the runtime (bytecode) libraries by running:</p>
190 % mkdir $CFEINSTALL/bytecode-libs
191 % gmake -C runtime install-bytecode
192 % setenv LLVM_LIB_SEARCH_PATH $CFEINSTALL/bytecode-libs
195 <li><p>Test the newly-installed C frontend by one or more of the
198 <li> compiling and running a "hello, LLVM" program in C and C++.</li>
199 <li> running the tests under <tt>test/Programs</tt> using <code>gmake -C
200 test/Programs</code></li>
205 <!-- *********************************************************************** -->
206 <div class="doc_section">
207 <a name="license">License Information</a>
210 <div class="doc_text">
212 The LLVM GCC frontend is licensed to you under the GNU General Public License
213 and the GNU Lesser General Public License. Please see the files COPYING and
214 COPYING.LIB for more details.
218 The software also has the following additional copyrights:
223 Copyright (c) 2003, 2004 University of Illinois at Urbana-Champaign.
230 University of Illinois at Urbana-Champaign
232 http://llvm.cs.uiuc.edu
234 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
235 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
236 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
237 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
238 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
239 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
243 Hewlett-Packard Company
245 Permission to use, copy, modify, distribute and sell this software
246 and its documentation for any purpose is hereby granted without fee,
247 provided that the above copyright notice appear in all copies and
248 that both that copyright notice and this permission notice appear
249 in supporting documentation. Hewlett-Packard Company makes no
250 representations about the suitability of this software for any
251 purpose. It is provided "as is" without express or implied warranty.
253 Copyright (c) 1996, 1997, 1998, 1999
254 Silicon Graphics Computer Systems, Inc.
256 Permission to use, copy, modify, distribute and sell this software
257 and its documentation for any purpose is hereby granted without fee,
258 provided that the above copyright notice appear in all copies and
259 that both that copyright notice and this permission notice appear
260 in supporting documentation. Silicon Graphics makes no
261 representations about the suitability of this software for any
262 purpose. It is provided "as is" without express or implied warranty.
266 <!-- *********************************************************************** -->
270 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
271 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
272 <a href="http://validator.w3.org/check/referer"><img
273 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
276 <a href="http://llvm.cs.uiuc.edu">LLVM Compiler Infrastructure</a><br>
277 Last modified: $Date$