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10
11<div class="doc_title">
12 Getting Started with the LLVM System
13</div>
14
15<ul>
16 <li><a href="#overview">Overview</a>
17 <li><a href="#quickstart">Getting Started Quickly (A Summary)</a>
18 <li><a href="#requirements">Requirements</a>
19 <ol>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]20 <li><a href="#hardware">Hardware</a></li>
21 <li><a href="#software">Software</a></li>
22 <li><a href="#brokengcc">Broken versions of GCC and other tools</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]23 </ol></li>
24
25 <li><a href="#starting">Getting Started with LLVM</a>
26 <ol>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]27 <li><a href="#terminology">Terminology and Notation</a></li>
28 <li><a href="#environment">Setting Up Your Environment</a></li>
29 <li><a href="#unpack">Unpacking the LLVM Archives</a></li>
30 <li><a href="#checkout">Checkout LLVM from Subversion</a></li>
31 <li><a href="#installcf">Install the GCC Front End</a></li>
32 <li><a href="#config">Local LLVM Configuration</a></li>
33 <li><a href="#compile">Compiling the LLVM Suite Source Code</a></li>
34 <li><a href="#cross-compile">Cross-Compiling LLVM</a></li>
35 <li><a href="#objfiles">The Location of LLVM Object Files</a></li>
36 <li><a href="#optionalconfig">Optional Configuration Items</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]37 </ol></li>
38
39 <li><a href="#layout">Program layout</a>
40 <ol>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]41 <li><a href="#examples"><tt>llvm/examples</tt></a></li>
42 <li><a href="#include"><tt>llvm/include</tt></a></li>
43 <li><a href="#lib"><tt>llvm/lib</tt></a></li>
44 <li><a href="#projects"><tt>llvm/projects</tt></a></li>
45 <li><a href="#runtime"><tt>llvm/runtime</tt></a></li>
46 <li><a href="#test"><tt>llvm/test</tt></a></li>
47 <li><a href="#llvmtest"><tt>llvm-test</tt></a></li>
48 <li><a href="#tools"><tt>llvm/tools</tt></a></li>
49 <li><a href="#utils"><tt>llvm/utils</tt></a></li>
50 <li><a href="#win32"><tt>llvm/win32</tt></a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]51 </ol></li>
52
53 <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
54 <ol>
55 <li><a href="#tutorial4">Example with llvm-gcc4</a></li>
56 </ol>
57 <li><a href="#problems">Common Problems</a>
58 <li><a href="#links">Links</a>
59</ul>
60
61<div class="doc_author">
62 <p>Written by:
63 <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
64 <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
65 <a href="http://misha.brukman.net">Misha Brukman</a>,
66 <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and
67 <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>.
68 </p>
69</div>
70
71
72<!-- *********************************************************************** -->
73<div class="doc_section">
74 <a name="overview"><b>Overview</b></a>
75</div>
76<!-- *********************************************************************** -->
77
78<div class="doc_text">
79
80<p>Welcome to LLVM! In order to get started, you first need to know some
81basic information.</p>
82
83<p>First, LLVM comes in two pieces. The first piece is the LLVM suite. This
84contains all of the tools, libraries, and header files needed to use the low
85level virtual machine. It contains an assembler, disassembler, bitcode
86analyzer and bitcode optimizer. It also contains a test suite that can be
87used to test the LLVM tools and the GCC front end.</p>
88
89<p>The second piece is the GCC front end. This component provides a version of
90GCC that compiles C and C++ code into LLVM bitcode. Currently, the GCC front
91end uses the GCC parser to convert code to LLVM. Once
92compiled into LLVM bitcode, a program can be manipulated with the LLVM tools
93from the LLVM suite.</p>
94
95<p>
96There is a third, optional piece called llvm-test. It is a suite of programs
97with a testing harness that can be used to further test LLVM's functionality
98and performance.
99</p>
100
101</div>
102
103<!-- *********************************************************************** -->
104<div class="doc_section">
105 <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
106</div>
107<!-- *********************************************************************** -->
108
109<div class="doc_text">
110
111<p>Here's the short story for getting up and running quickly with LLVM:</p>
112
113<ol>
114 <li>Read the documentation.</li>
115 <li>Read the documentation.</li>
116 <li>Remember that you were warned twice about reading the documentation.</li>
Jim Grosbach73e74f72009-12-17 17:18:11 +0000[diff] [blame]117 <li>Install the llvm-gcc-4.2 front end if you intend to compile C or C++
118 (see <a href="#installcf">Install the GCC Front End</a> for details):</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]119 <ol>
120 <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li>
Jim Grosbach73e74f72009-12-17 17:18:11 +0000[diff] [blame]121 <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf -</tt></li>
122 <li><tt><i>install-binutils-binary-from-MinGW</i></tt> (Windows only)</li>
123 <li>Note: If the binary extension is "<tt>.bz</tt>" use <tt>bunzip2</tt> instead of <tt>gunzip</tt>.</li>
124 <li>Note: On Windows, use <a href="http://www.7-zip.org">7-Zip</a> or a similar archiving tool.</li>
125 <li>Add <tt>llvm-gcc</tt>'s "<tt>bin</tt>" directory to your <tt>PATH</tt> environment variable.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]126 </ol></li>
127
128 <li>Get the LLVM Source Code
129 <ul>
130 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
131 <ol>
132 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
133 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
134 </ol></li>
135
136 </ul></li>
137
138 <li><b>[Optional]</b> Get the Test Suite Source Code
139 <ul>
140 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
141 <ol>
142 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
143 <li><tt>cd llvm/projects</tt>
144 <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
145 </ol></li>
146
147 </ul></li>
148
149
150 <li>Configure the LLVM Build Environment
151 <ol>
152 <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
153 <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br>
154 Some common options:
155
156 <ul>
157 <li><tt>--prefix=<i>directory</i></tt>
158 <p>Specify for <i>directory</i> the full pathname of where you
159 want the LLVM tools and libraries to be installed (default
160 <tt>/usr/local</tt>).</p></li>
161 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
162 <p>Optionally, specify for <i>directory</i> the full pathname of the
163 C/C++ front end installation to use with this LLVM configuration. If
Duncan Sandscff3d042009-04-18 12:40:19 +0000[diff] [blame]164 not specified, the PATH will be searched. This is only needed if you
165 want to run the testsuite or do some special kinds of LLVM builds.</p></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]166 <li><tt>--enable-spec2000=<i>directory</i></tt>
167 <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
168 benchmarks should be available in
169 <tt><i>directory</i></tt>.</p></li>
170 </ul>
171 </ol></li>
172
173 <li>Build the LLVM Suite:
174 <ol>
175 <li><tt>gmake -k |&amp; tee gnumake.out
176 &nbsp;&nbsp;&nbsp;# this is csh or tcsh syntax</tt></li>
177 <li>If you get an "internal compiler error (ICE)" or test failures, see
178 <a href="#brokengcc">below</a>.</li>
179 </ol>
180
181</ol>
182
183<p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
184detailed information on configuring and compiling LLVM. See <a
185href="#environment">Setting Up Your Environment</a> for tips that simplify
186working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
187Layout</a> to learn about the layout of the source code tree.</p>
188
189</div>
190
191<!-- *********************************************************************** -->
192<div class="doc_section">
193 <a name="requirements"><b>Requirements</b></a>
194</div>
195<!-- *********************************************************************** -->
196
197<div class="doc_text">
198
199<p>Before you begin to use the LLVM system, review the requirements given below.
200This may save you some trouble by knowing ahead of time what hardware and
201software you will need.</p>
202
203</div>
204
205<!-- ======================================================================= -->
206<div class="doc_subsection">
207 <a name="hardware"><b>Hardware</b></a>
208</div>
209
210<div class="doc_text">
211
212<p>LLVM is known to work on the following platforms:</p>
213
214<table cellpadding="3" summary="Known LLVM platforms">
215<tr>
216 <th>OS</th>
217 <th>Arch</th>
218 <th>Compilers</th>
219</tr>
220<tr>
Chris Lattner6abf6762009-07-22 04:21:40 +0000[diff] [blame]221 <td>AuroraUX</td>
222 <td>x86<sup><a href="#pf_1">1</a></sup></td>
223 <td>GCC</td>
Chris Lattnera8f23072009-07-21 22:47:03 +0000[diff] [blame]224</tr>
225<tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]226 <td>Linux</td>
227 <td>x86<sup><a href="#pf_1">1</a></sup></td>
228 <td>GCC</td>
229</tr>
230<tr>
Edward O'Callaghan82a57db2009-08-04 05:24:28 +0000[diff] [blame]231 <td>Linux</td>
232 <td>amd64</td>
233 <td>GCC</td>
234</tr>
235<tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]236 <td>Solaris</td>
237 <td>V9 (Ultrasparc)</td>
238 <td>GCC</td>
239</tr>
240<tr>
241 <td>FreeBSD</td>
242 <td>x86<sup><a href="#pf_1">1</a></sup></td>
243 <td>GCC</td>
244</tr>
245<tr>
246 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
247 <td>PowerPC</td>
248 <td>GCC</td>
249</tr>
250<tr>
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]251 <td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]252 <td>x86</td>
253 <td>GCC</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]254</tr>
255<tr>
256 <td>Cygwin/Win32</td>
Anton Korobeynikovde76e8d2009-12-09 17:26:02 +0000[diff] [blame]257 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a>,
258 <a href="#pf_11">11</a></sup></td>
Anton Korobeynikovd24f4602010-02-11 21:51:51 +0000[diff] [blame]259 <td>GCC 3.4.X, binutils 2.20</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]260</tr>
261<tr>
262 <td>MinGW/Win32</td>
Anton Korobeynikovbad20c32009-08-06 12:54:58 +0000[diff] [blame]263 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,
264 <a href="#pf_8">8</a>, <a href="#pf_10">10</a></sup></td>
Anton Korobeynikovd24f4602010-02-11 21:51:51 +0000[diff] [blame]265 <td>GCC 3.4.X, binutils 2.20</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]266</tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]267</table>
268
269<p>LLVM has partial support for the following platforms:</p>
270
271<table summary="LLVM partial platform support">
272<tr>
273 <th>OS</th>
274 <th>Arch</th>
275 <th>Compilers</th>
276</tr>
277<tr>
278 <td>Windows</td>
279 <td>x86<sup><a href="#pf_1">1</a></sup></td>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]280 <td>Visual Studio 2005 SP1 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]281<tr>
282 <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
283 <td>PowerPC</td>
284 <td>GCC</td>
285</tr>
286<tr>
287 <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
288 <td>PowerPC</td>
289 <td>GCC</td>
290</tr>
291
292<tr>
293 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
294 <td>Alpha</td>
295 <td>GCC</td>
296</tr>
297<tr>
298 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
299 <td>Itanium (IA-64)</td>
300 <td>GCC</td>
301</tr>
302<tr>
303 <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
304 <td>Itanium (IA-64)</td>
305 <td>HP aCC</td>
306</tr>
307</table>
308
309<p><b>Notes:</b></p>
310
311<div class="doc_notes">
312<ol>
313<li><a name="pf_1">Code generation supported for Pentium processors and
314up</a></li>
315<li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
316<li><a name="pf_3">No native code generation</a></li>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]317<li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]318<li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
Chris Lattner789ce3a2009-01-02 07:10:51 +0000[diff] [blame]319<li><a name="pf_6">The port is done using the MSYS shell.</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]320<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
Anton Korobeynikovd24f4602010-02-11 21:51:51 +0000[diff] [blame]321<li><a name="pf_8">Binutils 2.20 or later is required to build the assembler
322 generated by LLVM properly.</a></li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]323<li><a name="pf_9">XCode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]324 internal LLVM assert messages when compiled for Release at optimization
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]325 levels greater than 0 (i.e., <i>"-O1"</i> and higher).
326 Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]327 if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
Anton Korobeynikovbad20c32009-08-06 12:54:58 +0000[diff] [blame]328<li><a name="pf_10">For MSYS/MinGW on Windows, be sure to install the MSYS
329 version of the perl package, and be sure it appears in your path
330 before any Windows-based versions such as Strawberry Perl and
331 ActivePerl, as these have Windows-specifics that will cause the
332 build to fail.</a></li>
Anton Korobeynikovde76e8d2009-12-09 17:26:02 +0000[diff] [blame]333<li><a name="pf_11">In general, LLVM modules requiring dynamic linking can
334 not be built on Windows. However, you can build LLVM tools using
335 <i>"make tools-only"</i>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]336</ol>
337</div>
338
339<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
340mode, depending on the system (it is so large because of all the debugging
341information and the fact that the libraries are statically linked into multiple
Chris Lattner15aeb9a2009-04-25 22:08:52 +0000[diff] [blame]342tools). If you do not need many of the tools and you are space-conscious, you
343can pass <tt>ONLY_TOOLS="tools you need"</tt> to make. The Release build
344requires considerably less space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]345
346<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
347guaranteed to do so. If compilation is successful, the LLVM utilities should be
348able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
349generation should work as well, although the generated native code may not work
350on your platform.</p>
351
352<p>The GCC front end is not very portable at the moment. If you want to get it
353to work on another platform, you can download a copy of the source and <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]354href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]355
356</div>
357
358<!-- ======================================================================= -->
359<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
360<div class="doc_text">
361 <p>Compiling LLVM requires that you have several software packages
362 installed. The table below lists those required packages. The Package column
363 is the usual name for the software package that LLVM depends on. The Version
364 column provides "known to work" versions of the package. The Notes column
365 describes how LLVM uses the package and provides other details.</p>
366 <table summary="Packages required to compile LLVM">
367 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
368
369 <tr>
370 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
371 <td>3.79, 3.79.1</td>
372 <td>Makefile/build processor</td>
373 </tr>
374
375 <tr>
376 <td><a href="http://gcc.gnu.org">GCC</a></td>
377 <td>3.4.2</td>
378 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
379 </tr>
380
381 <tr>
382 <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
383 <td>4.5</td>
384 <td>For building the CFE</td>
385 </tr>
386
387 <tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]388 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
389 <td>&ge;1.3</td>
390 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
391 </tr>
392
393 <tr>
394 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
395 <td>1.4.2</td>
396 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
397 </tr>
398
399 <tr>
400 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
401 <td>8.3, 8.4</td>
402 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
403 </tr>
404
405 <tr>
406 <td><a href="http://expect.nist.gov/">expect</a></td>
407 <td>5.38.0</td>
408 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
409 </tr>
410
411 <tr>
412 <td><a href="http://www.perl.com/download.csp">perl</a></td>
413 <td>&ge;5.6.0</td>
414 <td>Nightly tester, utilities</td>
415 </tr>
416
417 <tr>
418 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
419 <td>1.4</td>
420 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
421 </tr>
422
423 <tr>
424 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
Nick Lewycky985d6d12009-09-27 04:56:27 +0000[diff] [blame]425 <td>2.60</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]426 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
427 </tr>
428
429 <tr>
430 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
Nick Lewycky985d6d12009-09-27 04:56:27 +0000[diff] [blame]431 <td>1.9.6</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]432 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
433 </tr>
434
435 <tr>
436 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
Nick Lewycky985d6d12009-09-27 04:56:27 +0000[diff] [blame]437 <td>1.5.22</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]438 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
439 </tr>
440
441 </table>
442
443 <p><b>Notes:</b></p>
444 <div class="doc_notes">
445 <ol>
446 <li><a name="sf1">Only the C and C++ languages are needed so there's no
447 need to build the other languages for LLVM's purposes.</a> See
448 <a href="#brokengcc">below</a> for specific version info.</li>
449 <li><a name="sf2">You only need Subversion if you intend to build from the
450 latest LLVM sources. If you're working from a release distribution, you
451 don't need Subversion.</a></li>
452 <li><a name="sf3">Only needed if you want to run the automated test
453 suite in the <tt>llvm/test</tt> directory.</a></li>
454 <li><a name="sf4">If you want to make changes to the configure scripts,
455 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
456 or higher). You will also need automake (1.9.2). We only use aclocal
457 from that package.</a></li>
458 </ol>
459 </div>
460
461 <p>Additionally, your compilation host is expected to have the usual
462 plethora of Unix utilities. Specifically:</p>
463 <ul>
464 <li><b>ar</b> - archive library builder</li>
465 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
466 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
467 <li><b>chmod</b> - change permissions on a file</li>
468 <li><b>cat</b> - output concatenation utility</li>
469 <li><b>cp</b> - copy files</li>
470 <li><b>date</b> - print the current date/time </li>
471 <li><b>echo</b> - print to standard output</li>
472 <li><b>egrep</b> - extended regular expression search utility</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]473 <li><b>find</b> - find files/dirs in a file system</li>
474 <li><b>grep</b> - regular expression search utility</li>
475 <li><b>gzip*</b> - gzip command for distribution generation</li>
476 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
477 <li><b>install</b> - install directories/files </li>
478 <li><b>mkdir</b> - create a directory</li>
479 <li><b>mv</b> - move (rename) files</li>
480 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
481 <li><b>rm</b> - remove (delete) files and directories</li>
482 <li><b>sed</b> - stream editor for transforming output</li>
483 <li><b>sh</b> - Bourne shell for make build scripts</li>
484 <li><b>tar</b> - tape archive for distribution generation</li>
485 <li><b>test</b> - test things in file system</li>
486 <li><b>unzip*</b> - unzip command for distribution checking</li>
487 <li><b>zip*</b> - zip command for distribution generation</li>
488 </ul>
489</div>
490
491<!-- ======================================================================= -->
492<div class="doc_subsection">
493 <a name="brokengcc">Broken versions of GCC and other tools</a>
494</div>
495
496<div class="doc_text">
497
498<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
499bugs in the compiler. In particular, several versions of GCC crash when trying
500to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
501successfully with them (however, see important notes below). Other versions
502of GCC will probably work as well. GCC versions listed
503here are known to not work. If you are using one of these versions, please try
504to upgrade your GCC to something more recent. If you run into a problem with a
505version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
506us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
507of GCC you are using.
508</p>
509
510<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
511problems in the STL that effectively prevent it from compiling LLVM.
512</p>
513
Chris Lattner76bb5302008-02-13 17:50:24 +0000[diff] [blame]514<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
515a bogus template error. This was fixed in later GCCs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]516
517<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
518href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
519the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
520
521<p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]522 Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]523 to a newer version</a> if possible.</p>
524<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
525 possibly others) does not compile LLVM correctly (it appears that exception
526 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
527 to a newer version of GCC.</p>
528<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
529 code generator, causing an infinite loop in the llvm-gcc build when built
530 with optimizations enabled (i.e. a release build).</p>
531<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
532 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
533 correctly compiles LLVM at -O2. A work around is to build release LLVM
534 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
535<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
536 miscompiles portions of LLVM</a>.</p>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]537<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
538 when building with optimizations enabled. It appears to work with
539 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
540 build.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]541<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
542 miscompile LLVM.</p>
543<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
544 default with ENABLE_OPTIMIZED=1. To work around this, build with
545 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
546<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
547 compiling some files. At the time of this writing, GCC mainline (4.2)
548 did not share the problem.</p>
549<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
550 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
551 code. LLVM will appear to mostly work but will be buggy, e.g. failing
552 portions of its testsuite.</p>
553<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
554platforms compiling md5.c gets a mangled constant.</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000[diff] [blame]555<p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
556to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
557about symbols remaining in the table on destruction.</p>
Nuno Lopesfc375a62008-12-10 16:11:10 +0000[diff] [blame]558<p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms
Nuno Lopesc36ac042008-12-10 16:01:22 +0000[diff] [blame]559as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
Anton Korobeynikov30403a02009-05-04 10:24:46 +0000[diff] [blame]560<p><b>Cygwin GCC 4.3.2 20080827 (beta) 2</b>:
561 Users <a href="http://llvm.org/PR4145">reported</a> various problems related
562 with link errors when using this GCC version.</p>
Chris Lattner5d834332009-09-10 16:25:02 +0000[diff] [blame]563<p><b>Debian GCC 4.3.2 on X86</b>: Crashes building some files in LLVM 2.6.</p>
Nick Lewyckyadb7b152009-07-17 06:32:10 +0000[diff] [blame]564<p><b>GCC 4.3.3 (Debian 4.3.3-10) on ARM</b>: Miscompiles parts of LLVM 2.6
565when optimizations are turned on. The symptom is an infinite loop in
Chris Lattner5d834332009-09-10 16:25:02 +0000[diff] [blame]566FoldingSetImpl::RemoveNode while running the code generator.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]567<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
568long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
569defined in a discarded section. You can safely ignore these messages as they are
570erroneous and the linkage is correct. These messages disappear using ld
5712.17.</p>
572
573<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
574href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
575causes huge link times (minutes instead of seconds) when building LLVM. We
576recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
577
Nick Lewycky87da07c2009-03-03 05:41:16 +0000[diff] [blame]578<p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained
Nick Lewycky829108e2009-02-25 06:29:47 +0000[diff] [blame]579<a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a>
580which causes intermittent failures when building LLVM with position independent
Nick Lewycky87da07c2009-03-03 05:41:16 +0000[diff] [blame]581code. The symptom is an error about cyclic dependencies. We recommend
582upgrading to a newer version of Gold.</p>
Nick Lewycky829108e2009-02-25 06:29:47 +0000[diff] [blame]583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]584</div>
585
586
587
588<!-- *********************************************************************** -->
589<div class="doc_section">
590 <a name="starting"><b>Getting Started with LLVM</b></a>
591</div>
592<!-- *********************************************************************** -->
593
594<div class="doc_text">
595
596<p>The remainder of this guide is meant to get you up and running with
597LLVM and to give you some basic information about the LLVM environment.</p>
598
599<p>The later sections of this guide describe the <a
600href="#layout">general layout</a> of the the LLVM source tree, a <a
601href="#tutorial">simple example</a> using the LLVM tool chain, and <a
602href="#links">links</a> to find more information about LLVM or to get
603help via e-mail.</p>
604</div>
605
606<!-- ======================================================================= -->
607<div class="doc_subsection">
608 <a name="terminology">Terminology and Notation</a>
609</div>
610
611<div class="doc_text">
612
613<p>Throughout this manual, the following names are used to denote paths
614specific to the local system and working environment. <i>These are not
615environment variables you need to set but just strings used in the rest
616of this document below</i>. In any of the examples below, simply replace
617each of these names with the appropriate pathname on your local system.
618All these paths are absolute:</p>
619
620<dl>
621 <dt>SRC_ROOT
622 <dd>
623 This is the top level directory of the LLVM source tree.
624 <br><br>
625
626 <dt>OBJ_ROOT
627 <dd>
628 This is the top level directory of the LLVM object tree (i.e. the
629 tree where object files and compiled programs will be placed. It
630 can be the same as SRC_ROOT).
631 <br><br>
632
633 <dt>LLVMGCCDIR
634 <dd>
635 This is where the LLVM GCC Front End is installed.
636 <p>
637 For the pre-built GCC front end binaries, the LLVMGCCDIR is
638 <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
639</dl>
640
641</div>
642
643<!-- ======================================================================= -->
644<div class="doc_subsection">
645 <a name="environment">Setting Up Your Environment</a>
646</div>
647
648<div class="doc_text">
649
650<p>
651In order to compile and use LLVM, you may need to set some environment
652variables.
653
654<dl>
655 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
656 <dd>[Optional] This environment variable helps LLVM linking tools find the
657 locations of your bitcode libraries. It is provided only as a
658 convenience since you can specify the paths using the -L options of the
659 tools and the C/C++ front-end will automatically use the bitcode files
660 installed in its
661 <tt>lib</tt> directory.</dd>
662</dl>
663
664</div>
665
666<!-- ======================================================================= -->
667<div class="doc_subsection">
668 <a name="unpack">Unpacking the LLVM Archives</a>
669</div>
670
671<div class="doc_text">
672
673<p>
674If you have the LLVM distribution, you will need to unpack it before you
675can begin to compile it. LLVM is distributed as a set of two files: the LLVM
676suite and the LLVM GCC front end compiled for your platform. There is an
677additional test suite that is optional. Each file is a TAR archive that is
678compressed with the gzip program.
679</p>
680
681<p>The files are as follows, with <em>x.y</em> marking the version number:
682<dl>
683 <dt><tt>llvm-x.y.tar.gz</tt></dt>
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]684 <dd>Source release for the LLVM libraries and tools.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]685
686 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
687 <dd>Source release for the LLVM test suite.</dd>
688
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]689 <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt>
690 <dd>Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]691 directory for build instructions.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]692
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]693 <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt>
694 <dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]695
696</dl>
697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]698</div>
699
700<!-- ======================================================================= -->
701<div class="doc_subsection">
702 <a name="checkout">Checkout LLVM from Subversion</a>
703</div>
704
705<div class="doc_text">
706
707<p>If you have access to our Subversion repository, you can get a fresh copy of
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]708the entire source code. All you need to do is check it out from Subversion as
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]709follows:</p>
710
711<ul>
712 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
713 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
714 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
715 llvm</tt></li>
716</ul>
717
718
719<p>This will create an '<tt>llvm</tt>' directory in the current
720directory and fully populate it with the LLVM source code, Makefiles,
721test directories, and local copies of documentation files.</p>
722
723<p>If you want to get a specific release (as opposed to the most recent
724revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
725'<tt>trunk</tt>'). The following releases are located in the following
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]726subdirectories of the '<tt>tags</tt>' directory:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]727
728<ul>
Tanya Lattner221f9d42009-10-23 06:20:06 +0000[diff] [blame]729<li>Release 2.6: <b>RELEASE_26</b></li>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]730<li>Release 2.5: <b>RELEASE_25</b></li>
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]731<li>Release 2.4: <b>RELEASE_24</b></li>
Tanya Lattner9eb3be52008-06-09 06:02:09 +0000[diff] [blame]732<li>Release 2.3: <b>RELEASE_23</b></li>
Tanya Lattner60030782008-02-12 02:42:55 +0000[diff] [blame]733<li>Release 2.2: <b>RELEASE_22</b></li>
Tanya Lattner2fad5b02007-09-28 22:50:54 +0000[diff] [blame]734<li>Release 2.1: <b>RELEASE_21</b></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]735<li>Release 2.0: <b>RELEASE_20</b></li>
736<li>Release 1.9: <b>RELEASE_19</b></li>
737<li>Release 1.8: <b>RELEASE_18</b></li>
738<li>Release 1.7: <b>RELEASE_17</b></li>
739<li>Release 1.6: <b>RELEASE_16</b></li>
740<li>Release 1.5: <b>RELEASE_15</b></li>
741<li>Release 1.4: <b>RELEASE_14</b></li>
742<li>Release 1.3: <b>RELEASE_13</b></li>
743<li>Release 1.2: <b>RELEASE_12</b></li>
744<li>Release 1.1: <b>RELEASE_11</b></li>
745<li>Release 1.0: <b>RELEASE_1</b></li>
746</ul>
747
748<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
749you get it from the Subversion repository:</p>
750
751<div class="doc_code">
752<pre>
753% cd llvm/projects
754% svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
755</pre>
756</div>
757
758<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
759configured by the LLVM configure script as well as automatically updated when
760you run <tt>svn update</tt>.</p>
761
762<p>If you would like to get the GCC front end source code, you can also get it
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]763and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]764instructions</a> to successfully get and build the LLVM GCC front-end.</p>
765
766</div>
767
768<!-- ======================================================================= -->
769<div class="doc_subsection">
770 <a name="installcf">Install the GCC Front End</a>
771</div>
772
773<div class="doc_text">
774
Jim Grosbach73e74f72009-12-17 17:18:11 +0000[diff] [blame]775<p>Before configuring and compiling the LLVM suite (or if you want to use just the LLVM
776GCC front end) you can optionally extract the front end from the binary distribution.
777It is used for running the llvm-test testsuite and for compiling C/C++ programs. Note that
778you can optionally <a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]779main LLVM repository.</p>
780
Jim Grosbach73e74f72009-12-17 17:18:11 +0000[diff] [blame]781<p>To install the GCC front end, do the following (on Windows, use an archival tool
782like <a href="http://www.7-zip.org">7-zip</a> that understands gzipped tars):</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]783
784<ol>
785 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]786 <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]787 -</tt></li>
788</ol>
789
Jim Grosbach73e74f72009-12-17 17:18:11 +0000[diff] [blame]790<p>Once the binary is uncompressed, if you're using a *nix-based system, add a symlink for
791<tt>llvm-gcc</tt> and <tt>llvm-g++</tt> to some directory in your path. If you're using a
792Windows-based system, add the <tt>bin</tt> subdirectory of your front end installation directory
793to your <tt>PATH</tt> environment variable. For example, if you uncompressed the binary to
794<tt>c:\llvm-gcc</tt>, add <tt>c:\llvm-gcc\bin</tt> to your <tt>PATH</tt>.</p>
795
796<p>If you now want to build LLVM from source, when you configure LLVM, it will
797automatically detect <tt>llvm-gcc</tt>'s presence (if it is in your path) enabling its
798use in llvm-test. Note that you can always build or install <tt>llvm-gcc</tt> at any
799point after building the main LLVM repository: just reconfigure llvm and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]800llvm-test will pick it up.
801</p>
802
Jim Grosbach73e74f72009-12-17 17:18:11 +0000[diff] [blame]803<p>As a convenience for Windows users, the front end binaries for MinGW/x86 include
804versions of the required w32api and mingw-runtime binaries. The last remaining step for
805Windows users is to simply uncompress the binary binutils package from
806<a href="http://mingw.org/">MinGW</a> into your front end installation directory. While the
807front end installation steps are not quite the same as a typical manual MinGW installation,
808they should be similar enough to those who have previously installed MinGW on Windows systems.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]809
Jim Grosbach73e74f72009-12-17 17:18:11 +0000[diff] [blame]810<p>To install binutils on Windows:</p>
811
812<ol>
813 <li><tt><i>download GNU Binutils from <a href="http://sourceforge.net/projects/mingw/files/">MinGW Downloads</a></i></tt></li>
814 <li><tt>cd <i>where-you-uncompressed-the-front-end</i></tt></li>
815 <li><tt><i>uncompress archived binutils directories (not the tar file) into the current directory</i></tt></li>
816</ol>
817
818<p>The binary versions of the LLVM GCC front end may not suit all of your needs. For
819example, the binary distribution may include an old version of a system header
820file, not "fix" a header file that needs to be fixed for GCC, or it may be linked with
821libraries not available on your system. In cases like these, you may want to try
822<a href="GCCFEBuildInstrs.html">building the GCC front end from source</a>. Thankfully,
823this is much easier now than it was in the past.</p>
824
825<p>We also do not currently support updating of the GCC front end by manually overlaying
826newer versions of the w32api and mingw-runtime binary packages that may become available
827from MinGW. At this time, it's best to think of the MinGW LLVM GCC front end binary as
828a self-contained convenience package that requires Windows users to simply download and
829uncompress the GNU Binutils binary package from the MinGW project.</p>
830
831<p>Regardless of your platform, if you discover that installing the LLVM GCC front end
832binaries is not as easy as previously described, or you would like to suggest improvements,
833please let us know how you would like to see things improved by dropping us a note on our
834<a href="http://llvm.org/docs/#maillist">mailing list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]835
836</div>
837
838<!-- ======================================================================= -->
839<div class="doc_subsection">
840 <a name="config">Local LLVM Configuration</a>
841</div>
842
843<div class="doc_text">
844
845 <p>Once checked out from the Subversion repository, the LLVM suite source
846 code must be
847configured via the <tt>configure</tt> script. This script sets variables in the
848various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
849<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
850the Makefiles needed to begin building LLVM.</p>
851
852<p>The following environment variables are used by the <tt>configure</tt>
853script to configure the build system:</p>
854
855<table summary="LLVM configure script environment variables">
856 <tr><th>Variable</th><th>Purpose</th></tr>
857 <tr>
858 <td>CC</td>
859 <td>Tells <tt>configure</tt> which C compiler to use. By default,
860 <tt>configure</tt> will look for the first GCC C compiler in
861 <tt>PATH</tt>. Use this variable to override
862 <tt>configure</tt>'s default behavior.</td>
863 </tr>
864 <tr>
865 <td>CXX</td>
866 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
867 <tt>configure</tt> will look for the first GCC C++ compiler in
868 <tt>PATH</tt>. Use this variable to override
869 <tt>configure</tt>'s default behavior.</td>
870 </tr>
871</table>
872
873<p>The following options can be used to set or enable LLVM specific options:</p>
874
875<dl>
876 <dt><i>--with-llvmgccdir</i></dt>
877 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
878 The value of this option should specify the full pathname of the C/C++ Front
879 End to be used. If this option is not provided, the PATH will be searched for
880 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
881 be inferred from the path found. If the option is not given, and no llvm-gcc
882 can be found in the path then a warning will be produced by
883 <tt>configure</tt> indicating this situation. LLVM may still be built with
884 the <tt>tools-only</tt> target but attempting to build the runtime libraries
885 will fail as these libraries require llvm-gcc and llvm-g++. See
886 <a href="#installcf">Install the GCC Front End</a> for details on installing
887 the C/C++ Front End. See
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]888 <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]889 for details on building the C/C++ Front End.</dd>
890 <dt><i>--with-tclinclude</i></dt>
891 <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
892 found. Use this if you have multiple tcl installations on your machine and you
893 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
894 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
895 option, the LLVM configure script will search for the tcl 8.4 and 8.3
896 releases.
897 <br><br>
898 </dd>
899 <dt><i>--enable-optimized</i></dt>
900 <dd>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]901 Enables optimized compilation (debugging symbols are removed
902 and GCC optimization flags are enabled). Note that this is the default
903 setting if you are using the LLVM distribution. The default behavior
904 of an Subversion checkout is to use an unoptimized build (also known as a
905 debug build).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]906 <br><br>
907 </dd>
908 <dt><i>--enable-debug-runtime</i></dt>
909 <dd>
910 Enables debug symbols in the runtime libraries. The default is to strip
911 debug symbols from the runtime libraries.
912 </dd>
913 <dt><i>--enable-jit</i></dt>
914 <dd>
915 Compile the Just In Time (JIT) compiler functionality. This is not
916 available
917 on all platforms. The default is dependent on platform, so it is best
918 to explicitly enable it if you want it.
919 <br><br>
920 </dd>
921 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
922 <dd>Controls which targets will be built and linked into llc. The default
923 value for <tt>target_options</tt> is "all" which builds and links all
924 available targets. The value "host-only" can be specified to build only a
925 native compiler (no cross-compiler targets available). The "native" target is
926 selected as the target of the build host. You can also specify a comma
927 separated list of target names that you want available in llc. The target
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]928 names use all lower case. The current set of targets is: <br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]929 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
930 <br><br></dd>
931 <dt><i>--enable-doxygen</i></dt>
932 <dd>Look for the doxygen program and enable construction of doxygen based
933 documentation from the source code. This is disabled by default because
934 generating the documentation can take a long time and producess 100s of
935 megabytes of output.</dd>
936 <dt><i>--with-udis86</i></dt>
937 <dd>LLVM can use external disassembler library for various purposes (now it's
938 used only for examining code produced by JIT). This option will enable usage
939 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
940 bits) disassembler library.</dd>
941</dl>
942
943<p>To configure LLVM, follow these steps:</p>
944
945<ol>
946 <li><p>Change directory into the object root directory:</p>
947
948 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
949
950 <li><p>Run the <tt>configure</tt> script located in the LLVM source
951 tree:</p>
952
953 <div class="doc_code">
954 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
955 </div></li>
956</ol>
957
958</div>
959
960<!-- ======================================================================= -->
961<div class="doc_subsection">
962 <a name="compile">Compiling the LLVM Suite Source Code</a>
963</div>
964
965<div class="doc_text">
966
967<p>Once you have configured LLVM, you can build it. There are three types of
968builds:</p>
969
970<dl>
971 <dt>Debug Builds
972 <dd>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]973 These builds are the default when one is using an Subversion checkout and
974 types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was
975 used during configuration). The build system will compile the tools and
976 libraries with debugging information. To get a Debug Build using the
977 LLVM distribution the <tt>--disable-optimized</tt> option must be passed
978 to <tt>configure</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]979 <br><br>
980
981 <dt>Release (Optimized) Builds
982 <dd>
983 These builds are enabled with the <tt>--enable-optimized</tt> option to
984 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
985 <tt>gmake</tt> command line. For these builds, the build system will
986 compile the tools and libraries with GCC optimizations enabled and strip
987 debugging information from the libraries and executables it generates.
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]988 Note that Release Builds are default when using an LLVM distribution.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]989 <br><br>
990
991 <dt>Profile Builds
992 <dd>
993 These builds are for use with profiling. They compile profiling
994 information into the code for use with programs like <tt>gprof</tt>.
995 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
996 on the <tt>gmake</tt> command line.
997</dl>
998
999<p>Once you have LLVM configured, you can build it by entering the
1000<i>OBJ_ROOT</i> directory and issuing the following command:</p>
1001
1002<div class="doc_code"><pre>% gmake</pre></div>
1003
1004<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
1005are using a version of GCC that is known not to compile LLVM.</p>
1006
1007<p>
1008If you have multiple processors in your machine, you may wish to use some of
1009the parallel build options provided by GNU Make. For example, you could use the
1010command:</p>
1011
1012<div class="doc_code"><pre>% gmake -j2</pre></div>
1013
1014<p>There are several special targets which are useful when working with the LLVM
1015source code:</p>
1016
1017<dl>
1018 <dt><tt>gmake clean</tt>
1019 <dd>
1020 Removes all files generated by the build. This includes object files,
1021 generated C/C++ files, libraries, and executables.
1022 <br><br>
1023
1024 <dt><tt>gmake dist-clean</tt>
1025 <dd>
1026 Removes everything that <tt>gmake clean</tt> does, but also removes files
1027 generated by <tt>configure</tt>. It attempts to return the source tree to the
1028 original state in which it was shipped.
1029 <br><br>
1030
1031 <dt><tt>gmake install</tt>
1032 <dd>
1033 Installs LLVM header files, libraries, tools, and documentation in a
1034 hierarchy
1035 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
1036 defaults to <tt>/usr/local</tt>.
1037 <br><br>
1038
1039 <dt><tt>gmake -C runtime install-bytecode</tt>
1040 <dd>
1041 Assuming you built LLVM into $OBJDIR, when this command is run, it will
1042 install bitcode libraries into the GCC front end's bitcode library
1043 directory. If you need to update your bitcode libraries,
1044 this is the target to use once you've built them.
1045 <br><br>
1046</dl>
1047
1048<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
1049details on these <tt>make</tt> targets and descriptions of other targets
1050available.</p>
1051
1052<p>It is also possible to override default values from <tt>configure</tt> by
1053declaring variables on the command line. The following are some examples:</p>
1054
1055<dl>
1056 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1057 <dd>
1058 Perform a Release (Optimized) build.
1059 <br><br>
1060
1061 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1062 <dd>
1063 Perform a Release (Optimized) build without assertions enabled.
1064 <br><br>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]1065
1066 <dt><tt>gmake ENABLE_OPTIMIZED=0</tt>
1067 <dd>
1068 Perform a Debug build.
1069 <br><br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1070
1071 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1072 <dd>
1073 Perform a Profiling build.
1074 <br><br>
1075
1076 <dt><tt>gmake VERBOSE=1</tt>
1077 <dd>
1078 Print what <tt>gmake</tt> is doing on standard output.
1079 <br><br>
1080
1081 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1082 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1083 the standard output. This also implies <tt>VERBOSE=1</tt>.
1084 <br><br></dd>
1085</dl>
1086
1087<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1088it and any subdirectories that it contains. Entering any directory inside the
1089LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1090that directory that is out of date.</p>
1091
1092</div>
1093
1094<!-- ======================================================================= -->
1095<div class="doc_subsection">
1096 <a name="cross-compile">Cross-Compiling LLVM</a>
1097</div>
1098
1099<div class="doc_text">
Jim Grosbachc8c74362009-04-17 17:25:16 +0000[diff] [blame]1100 <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
1101 executables and libraries to be hosted on a platform different from the
1102 platform where they are build (a Canadian Cross build). To configure a
1103 cross-compile, supply the configure script with <tt>--build</tt> and
1104 <tt>--host</tt> options that are different. The values of these options must
1105 be legal target triples that your GCC compiler supports.</p>
1106
1107 <p>The result of such a build is executables that are not runnable on
1108 on the build host (--build option) but can be executed on the compile host
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1109 (--host option).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1110</div>
1111
1112<!-- ======================================================================= -->
1113<div class="doc_subsection">
1114 <a name="objfiles">The Location of LLVM Object Files</a>
1115</div>
1116
1117<div class="doc_text">
1118
1119<p>The LLVM build system is capable of sharing a single LLVM source tree among
1120several LLVM builds. Hence, it is possible to build LLVM for several different
1121platforms or configurations using the same source tree.</p>
1122
1123<p>This is accomplished in the typical autoconf manner:</p>
1124
1125<ul>
1126 <li><p>Change directory to where the LLVM object files should live:</p>
1127
1128 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1129
1130 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1131 directory:</p>
1132
1133 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1134</ul>
1135
1136<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1137named after the build type:</p>
1138
1139<dl>
1140 <dt>Debug Builds
1141 <dd>
1142 <dl>
1143 <dt>Tools
1144 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1145 <dt>Libraries
1146 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1147 </dl>
1148 <br><br>
1149
1150 <dt>Release Builds
1151 <dd>
1152 <dl>
1153 <dt>Tools
1154 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1155 <dt>Libraries
1156 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1157 </dl>
1158 <br><br>
1159
1160 <dt>Profile Builds
1161 <dd>
1162 <dl>
1163 <dt>Tools
1164 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1165 <dt>Libraries
1166 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1167 </dl>
1168</dl>
1169
1170</div>
1171
1172<!-- ======================================================================= -->
1173<div class="doc_subsection">
1174 <a name="optionalconfig">Optional Configuration Items</a>
1175</div>
1176
1177<div class="doc_text">
1178
1179<p>
1180If you're running on a Linux system that supports the "<a
1181href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1182module, and you have root access on the system, you can set your system up to
1183execute LLVM bitcode files directly. To do this, use commands like this (the
1184first command may not be required if you are already using the module):</p>
1185
1186<div class="doc_code">
1187<pre>
1188$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
Nick Lewyckyb3673802009-11-04 06:15:28 +0000[diff] [blame]1189$ echo ':llvm:M::BC::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1190$ chmod u+x hello.bc (if needed)
1191$ ./hello.bc
1192</pre>
1193</div>
1194
1195<p>
Chris Lattneref515e42010-02-17 18:33:13 +0000[diff] [blame]1196This allows you to execute LLVM bitcode files directly. On Debian, you
1197can also use this command instead of the 'echo' command above:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1198</p>
1199
Chris Lattneref515e42010-02-17 18:33:13 +0000[diff] [blame]1200<div class="doc_code">
1201<pre>
1202$ sudo update-binfmts --install llvm /path/to/lli --magic 'BC'
1203</pre>
1204</div>
1205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1206</div>
1207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1208<!-- *********************************************************************** -->
1209<div class="doc_section">
1210 <a name="layout"><b>Program Layout</b></a>
1211</div>
1212<!-- *********************************************************************** -->
1213
1214<div class="doc_text">
1215
1216<p>One useful source of information about the LLVM source base is the LLVM <a
1217href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1218href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1219The following is a brief introduction to code layout:</p>
1220
1221</div>
1222
1223<!-- ======================================================================= -->
1224<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1225<div class="doc_text">
1226 <p>This directory contains some simple examples of how to use the LLVM IR and
1227 JIT.</p>
1228</div>
1229
1230<!-- ======================================================================= -->
1231<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1232<div class="doc_text">
1233
1234<p>This directory contains public header files exported from the LLVM
1235library. The three main subdirectories of this directory are:</p>
1236
1237<dl>
1238 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1239 <dd>This directory contains all of the LLVM specific header files. This
1240 directory also has subdirectories for different portions of LLVM:
1241 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1242 etc...</dd>
1243
1244 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1245 <dd>This directory contains generic support libraries that are provided with
1246 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1247 and a Command Line option processing library store their header files here.
1248 </dd>
1249
1250 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1251 <dd>This directory contains header files configured by the <tt>configure</tt>
1252 script. They wrap "standard" UNIX and C header files. Source code can
1253 include these header files which automatically take care of the conditional
1254 #includes that the <tt>configure</tt> script generates.</dd>
1255</dl>
1256</div>
1257
1258<!-- ======================================================================= -->
1259<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1260<div class="doc_text">
1261
1262<p>This directory contains most of the source files of the LLVM system. In LLVM,
1263almost all code exists in libraries, making it very easy to share code among the
1264different <a href="#tools">tools</a>.</p>
1265
1266<dl>
1267 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1268 <dd> This directory holds the core LLVM source files that implement core
1269 classes like Instruction and BasicBlock.</dd>
1270
1271 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1272 <dd>This directory holds the source code for the LLVM assembly language parser
1273 library.</dd>
1274
1275 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1276 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1277
1278 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1279 different program analyses, such as Dominator Information, Call Graphs,
1280 Induction Variables, Interval Identification, Natural Loop Identification,
1281 etc.</dd>
1282
1283 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1284 <dd> This directory contains the source code for the LLVM to LLVM program
1285 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1286 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1287 Elimination, and many others.</dd>
1288
1289 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1290 <dd> This directory contains files that describe various target architectures
1291 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1292 directory holds the X86 machine description while
1293 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1294
1295 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1296 <dd> This directory contains the major parts of the code generator: Instruction
1297 Selector, Instruction Scheduling, and Register Allocation.</dd>
1298
1299 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1300 <dd> This directory contains the source level debugger library that makes
1301 it possible to instrument LLVM programs so that a debugger could identify
1302 source code locations at which the program is executing.</dd>
1303
1304 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1305 <dd> This directory contains libraries for executing LLVM bitcode directly
1306 at runtime in both interpreted and JIT compiled fashions.</dd>
1307
1308 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1309 <dd> This directory contains the source code that corresponds to the header
1310 files located in <tt>llvm/include/Support/</tt>.</dd>
1311
1312 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1313 <dd>This directory contains the operating system abstraction layer that
1314 shields LLVM from platform-specific coding.</dd>
1315</dl>
1316
1317</div>
1318
1319<!-- ======================================================================= -->
1320<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1321<div class="doc_text">
1322 <p>This directory contains projects that are not strictly part of LLVM but are
1323 shipped with LLVM. This is also the directory where you should create your own
1324 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
Chris Lattneraf1df782008-08-11 06:13:31 +0000[diff] [blame]1325 to set up your own project.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1326</div>
1327
1328<!-- ======================================================================= -->
1329<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1330<div class="doc_text">
1331
1332<p>This directory contains libraries which are compiled into LLVM bitcode and
1333used when linking programs with the GCC front end. Most of these libraries are
1334skeleton versions of real libraries; for example, libc is a stripped down
1335version of glibc.</p>
1336
1337<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1338end to compile.</p>
1339
1340</div>
1341
1342<!-- ======================================================================= -->
1343<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1344<div class="doc_text">
1345 <p>This directory contains feature and regression tests and other basic sanity
1346 checks on the LLVM infrastructure. These are intended to run quickly and cover
1347 a lot of territory without being exhaustive.</p>
1348</div>
1349
1350<!-- ======================================================================= -->
1351<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1352<div class="doc_text">
1353 <p>This is not a directory in the normal llvm module; it is a separate
1354 Subversion
1355 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1356 This
1357 module contains a comprehensive correctness, performance, and benchmarking
1358 test
1359 suite for LLVM. It is a separate Subversion module because not every LLVM
1360 user is
1361 interested in downloading or building such a comprehensive test suite. For
1362 further details on this test suite, please see the
1363 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1364</div>
1365
1366<!-- ======================================================================= -->
1367<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1368<div class="doc_text">
1369
1370<p>The <b>tools</b> directory contains the executables built out of the
1371libraries above, which form the main part of the user interface. You can
Duncan Sandsc5c38f02010-02-18 14:08:13 +0000[diff] [blame]1372always get help for a tool by typing <tt>tool_name -help</tt>. The
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1373following is a brief introduction to the most important tools. More detailed
1374information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1375
1376<dl>
1377
1378 <dt><tt><b>bugpoint</b></tt></dt>
1379 <dd><tt>bugpoint</tt> is used to debug
1380 optimization passes or code generation backends by narrowing down the
1381 given test case to the minimum number of passes and/or instructions that
1382 still cause a problem, whether it is a crash or miscompilation. See <a
1383 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1384 on using <tt>bugpoint</tt>.</dd>
1385
1386 <dt><tt><b>llvmc</b></tt></dt>
1387 <dd>The LLVM Compiler Driver. This program can
1388 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1389 pre-processing, translation, optimization, assembly, and linking of programs
1390 all from one command line. <tt>llvmc</tt> also takes care of processing the
1391 dependent libraries found in bitcode. This reduces the need to get the
1392 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1393 note that this tool, while functional, is still experimental and not feature
1394 complete.</dd>
1395
1396 <dt><tt><b>llvm-ar</b></tt></dt>
1397 <dd>The archiver produces an archive containing
1398 the given LLVM bitcode files, optionally with an index for faster
1399 lookup.</dd>
1400
1401 <dt><tt><b>llvm-as</b></tt></dt>
1402 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1403 bitcode.</dd>
1404
1405 <dt><tt><b>llvm-dis</b></tt></dt>
1406 <dd>The disassembler transforms the LLVM bitcode to human readable
1407 LLVM assembly.</dd>
1408
1409 <dt><tt><b>llvm-ld</b></tt></dt>
1410 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1411 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1412 optimizations and allows optimization modules to be loaded and run so that
1413 language specific optimizations can be applied at link time.</dd>
1414
1415 <dt><tt><b>llvm-link</b></tt></dt>
1416 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1417 a single program.</dd>
1418
1419 <dt><tt><b>lli</b></tt></dt>
1420 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +0000[diff] [blame]1421 can directly execute LLVM bitcode (although very slowly...). For architectures
1422 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1423 will function as a Just-In-Time compiler (if the functionality was compiled
1424 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1425
1426 <dt><tt><b>llc</b></tt></dt>
1427 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1428 translates LLVM bitcode to a native code assembly file or to C code (with
1429 the -march=c option).</dd>
1430
1431 <dt><tt><b>llvm-gcc</b></tt></dt>
1432 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1433 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1434 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1435 usual machine code output. It works just like any other GCC compiler,
1436 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1437 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1438 separate Subversion module.</dd>
1439
1440 <dt><tt><b>opt</b></tt></dt>
1441 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1442 transformations (which are specified on the command line), and then outputs
Duncan Sandsc5c38f02010-02-18 14:08:13 +0000[diff] [blame]1443 the resultant bitcode. The '<tt>opt -help</tt>' command is a good way to
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]1444 get a list of the program transformations available in LLVM.<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1445 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1446 LLVM bitcode file and print out the results. It is primarily useful for
1447 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1448</dl>
1449</div>
1450
1451<!-- ======================================================================= -->
1452<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1453<div class="doc_text">
1454
1455<p>This directory contains utilities for working with LLVM source code, and some
1456of the utilities are actually required as part of the build process because they
1457are code generators for parts of LLVM infrastructure.</p>
1458
1459<dl>
1460 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1461 that finds differences between code that LLC generates and code that LLI
1462 generates. This is a useful tool if you are debugging one of them,
1463 assuming that the other generates correct output. For the full user
1464 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1465
1466 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1467 syntax-highlighting files which will work with Emacs and XEmacs editors,
1468 providing syntax highlighting support for LLVM assembly files and TableGen
1469 description files. For information on how to use the syntax files, consult
1470 the <tt>README</tt> file in that directory.<br><br>
1471
1472 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1473 and outputs all non-generated source files, which is useful if one wishes
1474 to do a lot of development across directories and does not want to
1475 individually find each file. One way to use it is to run, for example:
1476 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1477 tree.<br><br>
1478
1479 <dt><tt><b>llvmgrep</b></tt></dt>
1480 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1481 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1482 line. This is a very efficient way of searching the source base for a
1483 particular regular expression.</dd>
1484
1485 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1486 files in the current directory and then compiles and links the tool that
1487 is the first argument. For example, assuming you are in the directory
1488 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1489 simply running <tt>makellvm llc</tt> will make a build of the current
1490 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1491 causing a re-linking of LLC.<br><br>
1492
1493 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1494 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1495 cron script to generate nightly status reports of the functionality of
1496 tools, and the results can be seen by following the appropriate link on
1497 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1498
1499 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1500 the tool used to generate register descriptions, instruction set
1501 descriptions, and even assemblers from common TableGen description
1502 files.<br><br>
1503
1504 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1505 syntax-highlighting files which will work with the VIM editor, providing
1506 syntax highlighting support for LLVM assembly files and TableGen
1507 description files. For information on how to use the syntax files, consult
1508 the <tt>README</tt> file in that directory.<br><br>
1509
1510</dl>
1511
1512</div>
1513
1514<!-- ======================================================================= -->
1515<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1516<div class="doc_text">
1517 <p>This directory contains build scripts and project files for use with
1518 Visual C++. This allows developers on Windows to build LLVM without the need
1519 for Cygwin. The contents of this directory should be considered experimental
1520 at this time.
1521 </p>
1522</div>
1523<!-- *********************************************************************** -->
1524<div class="doc_section">
1525 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1526</div>
1527<!-- *********************************************************************** -->
1528
1529<div class="doc_text">
1530<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
Chris Lattnere6099642009-04-10 15:38:51 +0000[diff] [blame]1531so we only include instructions for llvm-gcc4.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1532</p>
1533
1534<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1535from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1536create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1537the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1538<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1539output.</p>
1540</div>
1541
1542<!-- ======================================================================= -->
1543<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1544
1545<div class="doc_text">
1546
1547<ol>
1548 <li><p>First, create a simple C file, name it 'hello.c':</p>
1549
1550<div class="doc_code">
1551<pre>
1552#include &lt;stdio.h&gt;
1553
1554int main() {
1555 printf("hello world\n");
1556 return 0;
1557}
1558</pre></div></li>
1559
1560 <li><p>Next, compile the C file into a native executable:</p>
1561
1562 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1563
1564 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1565 -c arguments work as usual (producing a native .s or .o file,
1566 respectively).</p></li>
1567
1568 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1569
1570 <div class="doc_code">
1571 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1572
1573 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1574 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1575 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1576 the bitcode file.</p>
1577
1578 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1579 </p></li>
1580
1581 <li><p>Run the program in both forms. To run the program, use:</p>
1582
1583 <div class="doc_code"><pre>% ./hello</pre></div>
1584
1585 <p>and</p>
1586
1587 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1588
1589 <p>The second examples shows how to invoke the LLVM JIT, <a
1590 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1591
1592 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1593 code:</p>
1594
1595<div class="doc_code">
1596<pre>llvm-dis &lt; hello.bc | less</pre>
1597</div></li>
1598
1599 <li><p>Compile the program to native assembly using the LLC code
1600 generator:</p>
1601
1602 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1603
1604 <li><p>Assemble the native assembly language file into a program:</p>
1605
1606<div class="doc_code">
1607<pre>
1608<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1609
1610<b>Others:</b> % gcc hello.s -o hello.native
1611</pre>
1612</div></li>
1613
1614 <li><p>Execute the native code program:</p>
1615
1616 <div class="doc_code"><pre>% ./hello.native</pre></div>
1617
1618 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1619 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1620 </li>
1621
1622</ol>
1623
1624</div>
1625
1626
1627<!-- *********************************************************************** -->
1628<div class="doc_section">
1629 <a name="problems">Common Problems</a>
1630</div>
1631<!-- *********************************************************************** -->
1632
1633<div class="doc_text">
1634
1635<p>If you are having problems building or using LLVM, or if you have any other
1636general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1637Asked Questions</a> page.</p>
1638
1639</div>
1640
1641<!-- *********************************************************************** -->
1642<div class="doc_section">
1643 <a name="links">Links</a>
1644</div>
1645<!-- *********************************************************************** -->
1646
1647<div class="doc_text">
1648
Bill Wendling08f49b92008-07-22 01:10:25 +0000[diff] [blame]1649<p>This document is just an <b>introduction</b> on how to use LLVM to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650some simple things... there are many more interesting and complicated things
1651that you can do that aren't documented here (but we'll gladly accept a patch
1652if you want to write something up!). For more information about LLVM, check
1653out:</p>
1654
1655<ul>
1656 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1657 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1658 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1659 that Uses LLVM</a></li>
1660</ul>
1661
1662</div>
1663
1664<!-- *********************************************************************** -->
1665
1666<hr>
1667<address>
1668 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]1669 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1670 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]1671 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1672
1673 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1674 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1675 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
1676 Last modified: $Date$
1677</address>
1678</body>
1679</html>