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Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]6 <title>Clang - Getting Started</title>
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10<body>
11
12<!--#include virtual="menu.html.incl"-->
13
14<div id="content">
15
16<h1>Getting Started: Building and Running Clang</h1>
17
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]18<p>This page gives you the shortest path to checking out Clang and demos a few
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]19options. This should get you up and running with the minimum of muss and fuss.
20If you like what you see, please consider <a href="get_involved.html">getting
Chris Lattnerd2c1c602009-11-09 03:18:18 +0000[diff] [blame]21involved</a> with the Clang community. If you run into problems, please file
Douglas Gregor9ff3e662010-10-07 20:20:57 +0000[diff] [blame]22bugs in <a href="http://llvm.org/bugs/">LLVM Bugzilla</a>.</p>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]23
Daniel Dunbarfa8e11b2010-11-02 22:34:04 +0000[diff] [blame]24<h2 id="download">Release Clang Versions</h2>
25
26<p>Clang has been released as part of regular LLVM releases since LLVM 2.6. You
27can download the release versions
28from <a href="http://llvm.org/releases/">http://llvm.org/releases/</a>.</p>
29
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]30<h2 id="build">Building Clang and Working with the Code</h2>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]31
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]32<h3 id="buildNix">On Unix-like Systems</h3>
33
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]34<p>If you would like to check out and build Clang, the current procedure is as
35follows:</p>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]36
37<ol>
Anton Korobeynikov1816e482009-08-06 13:00:08 +0000[diff] [blame]38 <li>Get the required tools.
39 <ul>
40 <li>See
41 <a href="http://llvm.org/docs/GettingStarted.html#requirements">
42 Getting Started with the LLVM System - Requirements</a>.</li>
43 <li>Note also that Python is needed for running the test suite.
44 Get it at: <a href="http://www.python.org/download">
45 http://www.python.org/download</a></li>
46 </ul>
47
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]48 <li>Checkout LLVM:
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]49 <ul>
Chris Lattner357f7ce2009-08-20 06:17:11 +0000[diff] [blame]50 <li>Change directory to where you want the llvm directory placed.</li>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]51 <li><tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]52 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]53 </li>
54 <li>Checkout Clang:
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]55 <ul>
Chandler Carruth4bc2d1e2012-08-14 00:41:30 +0000[diff] [blame]56 <li><tt>cd llvm/tools</tt></li>
Chris Lattner357f7ce2009-08-20 06:17:11 +0000[diff] [blame]57 <li><tt>svn co http://llvm.org/svn/llvm-project/cfe/trunk clang</tt></li>
Chandler Carruth4bc2d1e2012-08-14 00:41:30 +0000[diff] [blame]58 <li><tt>cd ../..</tt></li>
Chris Lattner357f7ce2009-08-20 06:17:11 +0000[diff] [blame]59 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]60 </li>
Chandler Carruthe56f3a62012-08-14 07:19:09 +0000[diff] [blame]61 <li>Checkout extra Clang Tools: (optional)
62 <ul>
63 <li><tt>cd llvm/tools/clang/tools</tt></li>
64 <li><tt>svn co http://llvm.org/svn/llvm-project/clang-tools-extra/trunk
65 extra</tt></li>
66 <li><tt>cd ../../../..</tt></li>
67 </ul>
68 </li>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]69 <li>Checkout Compiler-RT:
Daniel Dunbar078f8592011-12-07 03:04:42 +0000[diff] [blame]70 <ul>
Chandler Carruth4bc2d1e2012-08-14 00:41:30 +0000[diff] [blame]71 <li><tt>cd llvm/projects</tt></li>
Daniel Dunbar078f8592011-12-07 03:04:42 +0000[diff] [blame]72 <li><tt>svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk
73 compiler-rt</tt></li>
Chandler Carruth4bc2d1e2012-08-14 00:41:30 +0000[diff] [blame]74 <li><tt>cd ../..</tt></li>
Daniel Dunbar078f8592011-12-07 03:04:42 +0000[diff] [blame]75 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]76 </li>
77 <li>Build LLVM and Clang:
Chris Lattner357f7ce2009-08-20 06:17:11 +0000[diff] [blame]78 <ul>
Rafael Espindolafa5fa972010-10-29 22:05:17 +0000[diff] [blame]79 <li><tt>mkdir build</tt> (for building without polluting the source dir)
80 </li>
81 <li><tt>cd build</tt></li>
82 <li><tt>../llvm/configure</tt></li>
Chris Lattner357f7ce2009-08-20 06:17:11 +0000[diff] [blame]83 <li><tt>make</tt></li>
84 <li>This builds both LLVM and Clang for debug mode.</li>
85 <li>Note: For subsequent Clang development, you can just do make at the
86 clang directory level.</li>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]87 <li>It is also possible to use CMake instead of the makefiles. With CMake
NAKAMURA Takumi831fb8d2012-11-27 23:34:28 +0000[diff] [blame]88 it is possible to generate project files for several IDEs: Xcode, Eclipse
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]89 CDT4, CodeBlocks, Qt-Creator (use the CodeBlocks generator), KDevelop3.</li>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]90 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]91 </li>
Chris Lattner78781782010-05-06 21:57:57 +0000[diff] [blame]92
Richard Smith896e42d2013-03-12 19:56:09 +0000[diff] [blame]93 <li>If you intend to use Clang's C++ support, you may need to tell it how
Chandler Carruthabccc1f2012-05-16 08:18:58 +0000[diff] [blame]94 to find your C++ standard library headers. In general, Clang will detect
95 the best version of libstdc++ headers available and use them - it will
96 look both for system installations of libstdc++ as well as installations
97 adjacent to Clang itself. If your configuration fits neither of these
98 scenarios, you can use the <tt>--with-gcc-toolchain</tt> configure option
99 to tell Clang where the gcc containing the desired libstdc++ is installed.
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]100 </li>
101 <li>Try it out (assuming you add llvm/Debug+Asserts/bin to your path):
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]102 <ul>
Daniel Dunbardd63b282009-12-11 23:04:35 +0000[diff] [blame]103 <li><tt>clang --help</tt></li>
104 <li><tt>clang file.c -fsyntax-only</tt> (check for correctness)</li>
105 <li><tt>clang file.c -S -emit-llvm -o -</tt> (print out unoptimized llvm code)</li>
106 <li><tt>clang file.c -S -emit-llvm -o - -O3</tt></li>
107 <li><tt>clang file.c -S -O3 -o -</tt> (output native machine code)</li>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]108 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]109 </li>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]110</ol>
111
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]112<p>Note that the C front-end uses LLVM, but does not depend on llvm-gcc. If you
113encounter problems with building Clang, make sure you have the latest SVN
114version of LLVM. LLVM contains support libraries for Clang that will be updated
115as well as development on Clang progresses.</p>
Ted Kremenek675a9ba2008-02-08 07:32:26 +0000[diff] [blame]116
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]117<h3>Simultaneously Building Clang and LLVM:</h3>
Eric Christopher562b4f32008-02-08 07:10:48 +0000[diff] [blame]118
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]119<p>Once you have checked out Clang into the llvm source tree it will build along
120with the rest of <tt>llvm</tt>. To build all of LLVM and Clang together all at
121once simply run <tt>make</tt> from the root LLVM directory.</p>
122
123<p><em>Note:</em> Observe that Clang is technically part of a separate
124Subversion repository. As mentioned above, the latest Clang sources are tied to
125the latest sources in the LLVM tree. You can update your toplevel LLVM project
126and all (possibly unrelated) projects inside it with <tt><b>make
127update</b></tt>. This will run <tt>svn update</tt> on all subdirectories related
128to subversion. </p>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]129
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]130<h3 id="buildWindows">Using Visual Studio</h3>
131
132<p>The following details setting up for and building Clang on Windows using
133Visual Studio:</p>
134
135<ol>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]136 <li>Get the required tools:
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]137 <ul>
138 <li><b>Subversion</b>. Source code control program. Get it from:
139 <a href="http://subversion.tigris.org/getting.html">
140 http://subversion.tigris.org/getting.html</a></li>
NAKAMURA Takumi0dffb7b2012-11-27 23:34:08 +0000[diff] [blame]141 <li><b>CMake</b>. This is used for generating Visual Studio solution and
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]142 project files. Get it from:
143 <a href="http://www.cmake.org/cmake/resources/software.html">
144 http://www.cmake.org/cmake/resources/software.html</a></li>
Chandler Carruth245a5382011-11-16 19:29:07 +0000[diff] [blame]145 <li><b>Visual Studio 2008 or 2010</b></li>
Chris Lattner357f7ce2009-08-20 06:17:11 +0000[diff] [blame]146 <li><b>Python</b>. This is needed only if you will be running the tests
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]147 (which is essential, if you will be developing for clang).
148 Get it from:
NAKAMURA Takumicc8770a2011-03-27 02:04:21 +0000[diff] [blame]149 <a href="http://www.python.org/download/">
150 http://www.python.org/download/</a></li>
Chris Lattner357f7ce2009-08-20 06:17:11 +0000[diff] [blame]151 <li><b>GnuWin32 tools</b>
152 These are also necessary for running the tests.
153 (Note that the grep from MSYS or Cygwin doesn't work with the tests
154 because of embedded double-quotes in the search strings. The GNU
155 grep does work in this case.)
NAKAMURA Takumicc8770a2011-03-27 02:04:21 +0000[diff] [blame]156 Get them from <a href="http://getgnuwin32.sourceforge.net/">
157 http://getgnuwin32.sourceforge.net/</a>.</li>
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]158 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]159 </li>
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]160
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]161 <li>Checkout LLVM:
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]162 <ul>
163 <li><tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
164 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]165 </li>
166 <li>Checkout Clang:
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]167 <ul>
168 <li><tt>cd llvm\tools</tt>
169 <li><tt>svn co http://llvm.org/svn/llvm-project/cfe/trunk clang</tt></li>
170 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]171 </li>
NAKAMURA Takumi0dffb7b2012-11-27 23:34:08 +0000[diff] [blame]172 <li>Run CMake to generate the Visual Studio solution and project files:
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]173 <ul>
Michael J. Spencer0de57862010-12-16 22:01:14 +0000[diff] [blame]174 <li><tt>cd ..\..</tt> (back to where you started)</li>
175 <li><tt>mkdir build</tt> (for building without polluting the source dir)</li>
176 <li><tt>cd build</tt></li>
Chandler Carruth245a5382011-11-16 19:29:07 +0000[diff] [blame]177 <li>If you are using Visual Studio 2008: <tt>cmake -G "Visual Studio 9 2008" ..\llvm</tt></li>
Michael J. Spencer0de57862010-12-16 22:01:14 +0000[diff] [blame]178 <li>Or if you are using Visual Studio 2010: <tt>cmake -G "Visual Studio 10" ..\llvm</tt></li>
John Thompson13eb5652011-04-06 18:22:12 +0000[diff] [blame]179 <li>See the <a href="http://www.llvm.org/docs/CMake.html">LLVM CMake guide</a> for
NAKAMURA Takumi0dffb7b2012-11-27 23:34:08 +0000[diff] [blame]180 more information on other configuration options for CMake.</li>
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]181 <li>The above, if successful, will have created an LLVM.sln file in the
NAKAMURA Takumi542c7622011-07-25 12:40:26 +0000[diff] [blame]182 <tt>build</tt> directory.
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]183 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]184 </li>
185 <li>Build Clang:
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]186 <ul>
187 <li>Open LLVM.sln in Visual Studio.</li>
Daniel Dunbardd63b282009-12-11 23:04:35 +0000[diff] [blame]188 <li>Build the "clang" project for just the compiler driver and front end, or
189 the "ALL_BUILD" project to build everything, including tools.</li>
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]190 </ul>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]191 </li>
Eli Friedmand1e1ef32009-08-03 19:42:28 +0000[diff] [blame]192 <li>Try it out (assuming you added llvm/debug/bin to your path). (See the
193 running examples from above.)</li>
194 <li>See <a href="hacking.html#testingWindows">
195 Hacking on clang - Testing using Visual Studio on Windows</a> for information
196 on running regression tests on Windows.</li>
197</ol>
198
199<p>Note that once you have checked out both llvm and clang, to synchronize
200to the latest code base, use the <tt>svn update</tt> command in both the
201llvm and llvm\tools\clang directories, as they are separate repositories.</p>
202
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]203<h2 id="driver">Clang Compiler Driver (Drop-in Substitute for GCC)</h2>
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]204
Daniel Dunbardd63b282009-12-11 23:04:35 +0000[diff] [blame]205<p>The <tt>clang</tt> tool is the compiler driver and front-end, which is
206designed to be a drop-in replacement for the <tt>gcc</tt> command. Here are
207some examples of how to use the high-level driver:
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]208</p>
209
210<pre class="code">
211$ <b>cat t.c</b>
212#include &lt;stdio.h&gt;
213int main(int argc, char **argv) { printf("hello world\n"); }
214$ <b>clang t.c</b>
215$ <b>./a.out</b>
216hello world
217</pre>
218
Chris Lattner63d423d2009-11-09 03:21:02 +0000[diff] [blame]219<p>The 'clang' driver is designed to work as closely to GCC as possible to
220 maximize portability. The only major difference between the two is that
221 Clang defaults to gnu99 mode while GCC defaults to gnu89 mode. If you see
Chris Lattnerd73fef62009-11-09 04:04:07 +0000[diff] [blame]222 weird link-time errors relating to inline functions, try passing -std=gnu89
Chris Lattner63d423d2009-11-09 03:21:02 +0000[diff] [blame]223 to clang.</p>
224
Ted Kremenek9b16da32009-03-27 16:32:57 +0000[diff] [blame]225<h2>Examples of using Clang</h2>
226
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]227<!-- Thanks to
228 http://shiflett.org/blog/2006/oct/formatting-and-highlighting-php-code-listings
229Site suggested using pre in CSS, but doesn't work in IE, so went for the <pre>
230tag. -->
231
232<pre class="code">
233$ <b>cat ~/t.c</b>
234typedef float V __attribute__((vector_size(16)));
235V foo(V a, V b) { return a+b*a; }
236</pre>
237
238
Ted Kremenek35f29c52008-06-17 13:48:36 +0000[diff] [blame]239<h3>Preprocessing:</h3>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]240
241<pre class="code">
242$ <b>clang ~/t.c -E</b>
243# 1 "/Users/sabre/t.c" 1
244
245typedef float V __attribute__((vector_size(16)));
246
247V foo(V a, V b) { return a+b*a; }
248</pre>
249
250
Ted Kremenek35f29c52008-06-17 13:48:36 +0000[diff] [blame]251<h3>Type checking:</h3>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]252
253<pre class="code">
254$ <b>clang -fsyntax-only ~/t.c</b>
255</pre>
256
257
Ted Kremenek35f29c52008-06-17 13:48:36 +0000[diff] [blame]258<h3>GCC options:</h3>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]259
260<pre class="code">
261$ <b>clang -fsyntax-only ~/t.c -pedantic</b>
Benjamin Kramer665a8dc2012-01-15 15:26:07 +0000[diff] [blame]262/Users/sabre/t.c:2:17: <span style="color:magenta">warning:</span> extension used
263<span style="color:darkgreen">typedef float V __attribute__((vector_size(16)));</span>
264<span style="color:blue"> ^</span>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]2651 diagnostic generated.
266</pre>
267
268
Ted Kremenek35f29c52008-06-17 13:48:36 +0000[diff] [blame]269<h3>Pretty printing from the AST:</h3>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]270
Sylvestre Ledrubed28ac2012-07-23 08:59:39 +0000[diff] [blame]271<p>Note, the <tt>-cc1</tt> argument indicates the compiler front-end, and
Daniel Dunbardd63b282009-12-11 23:04:35 +0000[diff] [blame]272not the driver, should be run. The compiler front-end has several additional
273Clang specific features which are not exposed through the GCC compatible driver
274interface.</p>
275
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]276<pre class="code">
Daniel Dunbardd63b282009-12-11 23:04:35 +0000[diff] [blame]277$ <b>clang -cc1 ~/t.c -ast-print</b>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]278typedef float V __attribute__(( vector_size(16) ));
279V foo(V a, V b) {
280 return a + b * a;
281}
282</pre>
283
284
Ted Kremenek35f29c52008-06-17 13:48:36 +0000[diff] [blame]285<h3>Code generation with LLVM:</h3>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]286
287<pre class="code">
Daniel Dunbardd63b282009-12-11 23:04:35 +0000[diff] [blame]288$ <b>clang ~/t.c -S -emit-llvm -o -</b>
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]289define &lt;4 x float&gt; @foo(&lt;4 x float&gt; %a, &lt;4 x float&gt; %b) {
290entry:
291 %mul = mul &lt;4 x float&gt; %b, %a
292 %add = add &lt;4 x float&gt; %mul, %a
293 ret &lt;4 x float&gt; %add
294}
Daniel Dunbardd63b282009-12-11 23:04:35 +0000[diff] [blame]295$ <b>clang -fomit-frame-pointer -O3 -S -o - t.c</b> <i># On x86_64</i>
296...
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]297_foo:
Daniel Dunbardd63b282009-12-11 23:04:35 +0000[diff] [blame]298Leh_func_begin1:
299 mulps %xmm0, %xmm1
300 addps %xmm1, %xmm0
301 ret
302Leh_func_end1:
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]303</pre>
304
Eric Christopher7dc0e572008-02-08 06:45:49 +0000[diff] [blame]305</div>
306</body>
307</html>