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6 <title>Getting Started with LLVM System</title>
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9<body>
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>
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]117 <li>Install the llvm-gcc-4.2 front end if you intend to compile C or C++:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]118 <ol>
119 <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li>
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]120 <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf -</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]121 </li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]122 <li>Note: If the binary extension is ".bz" use bunzip2 instead of gunzip.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li>Add llvm-gcc's "bin" directory to your PATH variable.</li>
124 </ol></li>
125
126 <li>Get the LLVM Source Code
127 <ul>
128 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
129 <ol>
130 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
131 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
132 </ol></li>
133
134 </ul></li>
135
136 <li><b>[Optional]</b> Get the Test Suite Source Code
137 <ul>
138 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
139 <ol>
140 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
141 <li><tt>cd llvm/projects</tt>
142 <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
143 </ol></li>
144
145 </ul></li>
146
147
148 <li>Configure the LLVM Build Environment
149 <ol>
150 <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
151 <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br>
152 Some common options:
153
154 <ul>
155 <li><tt>--prefix=<i>directory</i></tt>
156 <p>Specify for <i>directory</i> the full pathname of where you
157 want the LLVM tools and libraries to be installed (default
158 <tt>/usr/local</tt>).</p></li>
159 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
160 <p>Optionally, specify for <i>directory</i> the full pathname of the
161 C/C++ front end installation to use with this LLVM configuration. If
Duncan Sandscff3d042009-04-18 12:40:19 +0000[diff] [blame]162 not specified, the PATH will be searched. This is only needed if you
163 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]164 <li><tt>--enable-spec2000=<i>directory</i></tt>
165 <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
166 benchmarks should be available in
167 <tt><i>directory</i></tt>.</p></li>
168 </ul>
169 </ol></li>
170
171 <li>Build the LLVM Suite:
172 <ol>
173 <li><tt>gmake -k |&amp; tee gnumake.out
174 &nbsp;&nbsp;&nbsp;# this is csh or tcsh syntax</tt></li>
175 <li>If you get an "internal compiler error (ICE)" or test failures, see
176 <a href="#brokengcc">below</a>.</li>
177 </ol>
178
179</ol>
180
181<p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
182detailed information on configuring and compiling LLVM. See <a
183href="#environment">Setting Up Your Environment</a> for tips that simplify
184working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
185Layout</a> to learn about the layout of the source code tree.</p>
186
187</div>
188
189<!-- *********************************************************************** -->
190<div class="doc_section">
191 <a name="requirements"><b>Requirements</b></a>
192</div>
193<!-- *********************************************************************** -->
194
195<div class="doc_text">
196
197<p>Before you begin to use the LLVM system, review the requirements given below.
198This may save you some trouble by knowing ahead of time what hardware and
199software you will need.</p>
200
201</div>
202
203<!-- ======================================================================= -->
204<div class="doc_subsection">
205 <a name="hardware"><b>Hardware</b></a>
206</div>
207
208<div class="doc_text">
209
210<p>LLVM is known to work on the following platforms:</p>
211
212<table cellpadding="3" summary="Known LLVM platforms">
213<tr>
214 <th>OS</th>
215 <th>Arch</th>
216 <th>Compilers</th>
217</tr>
218<tr>
Chris Lattner6abf6762009-07-22 04:21:40 +0000[diff] [blame]219 <td>AuroraUX</td>
220 <td>x86<sup><a href="#pf_1">1</a></sup></td>
221 <td>GCC</td>
Chris Lattnera8f23072009-07-21 22:47:03 +0000[diff] [blame]222</tr>
223<tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]224 <td>Linux</td>
225 <td>x86<sup><a href="#pf_1">1</a></sup></td>
226 <td>GCC</td>
227</tr>
228<tr>
Edward O'Callaghan82a57db2009-08-04 05:24:28 +0000[diff] [blame]229 <td>Linux</td>
230 <td>amd64</td>
231 <td>GCC</td>
232</tr>
233<tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]234 <td>Solaris</td>
235 <td>V9 (Ultrasparc)</td>
236 <td>GCC</td>
237</tr>
238<tr>
239 <td>FreeBSD</td>
240 <td>x86<sup><a href="#pf_1">1</a></sup></td>
241 <td>GCC</td>
242</tr>
243<tr>
244 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
245 <td>PowerPC</td>
246 <td>GCC</td>
247</tr>
248<tr>
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]249 <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]250 <td>x86</td>
251 <td>GCC</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]252</tr>
253<tr>
254 <td>Cygwin/Win32</td>
255 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a></sup></td>
256 <td>GCC 3.4.X, binutils 2.15</td>
257</tr>
258<tr>
259 <td>MinGW/Win32</td>
Anton Korobeynikovbad20c32009-08-06 12:54:58 +0000[diff] [blame^]260 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,
261 <a href="#pf_8">8</a>, <a href="#pf_10">10</a></sup></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]262 <td>GCC 3.4.X, binutils 2.15</td>
263</tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]264</table>
265
266<p>LLVM has partial support for the following platforms:</p>
267
268<table summary="LLVM partial platform support">
269<tr>
270 <th>OS</th>
271 <th>Arch</th>
272 <th>Compilers</th>
273</tr>
274<tr>
275 <td>Windows</td>
276 <td>x86<sup><a href="#pf_1">1</a></sup></td>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]277 <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]278<tr>
279 <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
280 <td>PowerPC</td>
281 <td>GCC</td>
282</tr>
283<tr>
284 <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
285 <td>PowerPC</td>
286 <td>GCC</td>
287</tr>
288
289<tr>
290 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
291 <td>Alpha</td>
292 <td>GCC</td>
293</tr>
294<tr>
295 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
296 <td>Itanium (IA-64)</td>
297 <td>GCC</td>
298</tr>
299<tr>
300 <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
301 <td>Itanium (IA-64)</td>
302 <td>HP aCC</td>
303</tr>
304</table>
305
306<p><b>Notes:</b></p>
307
308<div class="doc_notes">
309<ol>
310<li><a name="pf_1">Code generation supported for Pentium processors and
311up</a></li>
312<li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
313<li><a name="pf_3">No native code generation</a></li>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]314<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]315<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]316<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]317<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
318<li><a name="pf_8">Binutils</a> up to post-2.17 has bug in bfd/cofflink.c
319 preventing LLVM from building correctly. Several workarounds have been
320 introduced into LLVM build system, but the bug can occur anytime in the
321 future. We highly recommend that you rebuild your current binutils with the
322 patch from <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=2659">
323 Binutils bugzilla</a>, if it wasn't already applied.</li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]324<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]325 internal LLVM assert messages when compiled for Release at optimization
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]326 levels greater than 0 (i.e., <i>"-O1"</i> and higher).
327 Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]328 if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
Anton Korobeynikovbad20c32009-08-06 12:54:58 +0000[diff] [blame^]329<li><a name="pf_10">For MSYS/MinGW on Windows, be sure to install the MSYS
330 version of the perl package, and be sure it appears in your path
331 before any Windows-based versions such as Strawberry Perl and
332 ActivePerl, as these have Windows-specifics that will cause the
333 build to fail.</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]334</ol>
335</div>
336
337<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
338mode, depending on the system (it is so large because of all the debugging
339information and the fact that the libraries are statically linked into multiple
Chris Lattner15aeb9a2009-04-25 22:08:52 +0000[diff] [blame]340tools). If you do not need many of the tools and you are space-conscious, you
341can pass <tt>ONLY_TOOLS="tools you need"</tt> to make. The Release build
342requires considerably less space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]343
344<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
345guaranteed to do so. If compilation is successful, the LLVM utilities should be
346able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
347generation should work as well, although the generated native code may not work
348on your platform.</p>
349
350<p>The GCC front end is not very portable at the moment. If you want to get it
351to work on another platform, you can download a copy of the source and <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]352href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]353
354</div>
355
356<!-- ======================================================================= -->
357<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
358<div class="doc_text">
359 <p>Compiling LLVM requires that you have several software packages
360 installed. The table below lists those required packages. The Package column
361 is the usual name for the software package that LLVM depends on. The Version
362 column provides "known to work" versions of the package. The Notes column
363 describes how LLVM uses the package and provides other details.</p>
364 <table summary="Packages required to compile LLVM">
365 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
366
367 <tr>
368 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
369 <td>3.79, 3.79.1</td>
370 <td>Makefile/build processor</td>
371 </tr>
372
373 <tr>
374 <td><a href="http://gcc.gnu.org">GCC</a></td>
375 <td>3.4.2</td>
376 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
377 </tr>
378
379 <tr>
380 <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
381 <td>4.5</td>
382 <td>For building the CFE</td>
383 </tr>
384
385 <tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]386 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
387 <td>&ge;1.3</td>
388 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
389 </tr>
390
391 <tr>
392 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
393 <td>1.4.2</td>
394 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
395 </tr>
396
397 <tr>
398 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
399 <td>8.3, 8.4</td>
400 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
401 </tr>
402
403 <tr>
404 <td><a href="http://expect.nist.gov/">expect</a></td>
405 <td>5.38.0</td>
406 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
407 </tr>
408
409 <tr>
410 <td><a href="http://www.perl.com/download.csp">perl</a></td>
411 <td>&ge;5.6.0</td>
412 <td>Nightly tester, utilities</td>
413 </tr>
414
415 <tr>
416 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
417 <td>1.4</td>
418 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
419 </tr>
420
421 <tr>
422 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
423 <td>2.59</td>
424 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
425 </tr>
426
427 <tr>
428 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
429 <td>1.9.2</td>
430 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
431 </tr>
432
433 <tr>
434 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
435 <td>1.5.10</td>
436 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
437 </tr>
438
439 </table>
440
441 <p><b>Notes:</b></p>
442 <div class="doc_notes">
443 <ol>
444 <li><a name="sf1">Only the C and C++ languages are needed so there's no
445 need to build the other languages for LLVM's purposes.</a> See
446 <a href="#brokengcc">below</a> for specific version info.</li>
447 <li><a name="sf2">You only need Subversion if you intend to build from the
448 latest LLVM sources. If you're working from a release distribution, you
449 don't need Subversion.</a></li>
450 <li><a name="sf3">Only needed if you want to run the automated test
451 suite in the <tt>llvm/test</tt> directory.</a></li>
452 <li><a name="sf4">If you want to make changes to the configure scripts,
453 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
454 or higher). You will also need automake (1.9.2). We only use aclocal
455 from that package.</a></li>
456 </ol>
457 </div>
458
459 <p>Additionally, your compilation host is expected to have the usual
460 plethora of Unix utilities. Specifically:</p>
461 <ul>
462 <li><b>ar</b> - archive library builder</li>
463 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
464 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
465 <li><b>chmod</b> - change permissions on a file</li>
466 <li><b>cat</b> - output concatenation utility</li>
467 <li><b>cp</b> - copy files</li>
468 <li><b>date</b> - print the current date/time </li>
469 <li><b>echo</b> - print to standard output</li>
470 <li><b>egrep</b> - extended regular expression search utility</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]471 <li><b>find</b> - find files/dirs in a file system</li>
472 <li><b>grep</b> - regular expression search utility</li>
473 <li><b>gzip*</b> - gzip command for distribution generation</li>
474 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
475 <li><b>install</b> - install directories/files </li>
476 <li><b>mkdir</b> - create a directory</li>
477 <li><b>mv</b> - move (rename) files</li>
478 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
479 <li><b>rm</b> - remove (delete) files and directories</li>
480 <li><b>sed</b> - stream editor for transforming output</li>
481 <li><b>sh</b> - Bourne shell for make build scripts</li>
482 <li><b>tar</b> - tape archive for distribution generation</li>
483 <li><b>test</b> - test things in file system</li>
484 <li><b>unzip*</b> - unzip command for distribution checking</li>
485 <li><b>zip*</b> - zip command for distribution generation</li>
486 </ul>
487</div>
488
489<!-- ======================================================================= -->
490<div class="doc_subsection">
491 <a name="brokengcc">Broken versions of GCC and other tools</a>
492</div>
493
494<div class="doc_text">
495
496<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
497bugs in the compiler. In particular, several versions of GCC crash when trying
498to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
499successfully with them (however, see important notes below). Other versions
500of GCC will probably work as well. GCC versions listed
501here are known to not work. If you are using one of these versions, please try
502to upgrade your GCC to something more recent. If you run into a problem with a
503version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
504us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
505of GCC you are using.
506</p>
507
508<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
509problems in the STL that effectively prevent it from compiling LLVM.
510</p>
511
Chris Lattner76bb5302008-02-13 17:50:24 +0000[diff] [blame]512<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
513a bogus template error. This was fixed in later GCCs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]514
515<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
516href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
517the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
518
519<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]520 Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]521 to a newer version</a> if possible.</p>
522<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
523 possibly others) does not compile LLVM correctly (it appears that exception
524 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
525 to a newer version of GCC.</p>
526<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
527 code generator, causing an infinite loop in the llvm-gcc build when built
528 with optimizations enabled (i.e. a release build).</p>
529<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
530 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
531 correctly compiles LLVM at -O2. A work around is to build release LLVM
532 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
533<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
534 miscompiles portions of LLVM</a>.</p>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]535<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
536 when building with optimizations enabled. It appears to work with
537 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
538 build.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]539<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
540 miscompile LLVM.</p>
541<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
542 default with ENABLE_OPTIMIZED=1. To work around this, build with
543 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
544<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
545 compiling some files. At the time of this writing, GCC mainline (4.2)
546 did not share the problem.</p>
547<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
548 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
549 code. LLVM will appear to mostly work but will be buggy, e.g. failing
550 portions of its testsuite.</p>
551<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
552platforms compiling md5.c gets a mangled constant.</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000[diff] [blame]553<p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
554to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
555about symbols remaining in the table on destruction.</p>
Nuno Lopesfc375a62008-12-10 16:11:10 +0000[diff] [blame]556<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]557as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
Anton Korobeynikov30403a02009-05-04 10:24:46 +0000[diff] [blame]558<p><b>Cygwin GCC 4.3.2 20080827 (beta) 2</b>:
559 Users <a href="http://llvm.org/PR4145">reported</a> various problems related
560 with link errors when using this GCC version.</p>
Nick Lewyckyadb7b152009-07-17 06:32:10 +0000[diff] [blame]561<p><b>GCC 4.3.3 (Debian 4.3.3-10) on ARM</b>: Miscompiles parts of LLVM 2.6
562when optimizations are turned on. The symptom is an infinite loop in
563FoldingSetImpl::RemoveNode while running the code generator.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
565long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
566defined in a discarded section. You can safely ignore these messages as they are
567erroneous and the linkage is correct. These messages disappear using ld
5682.17.</p>
569
570<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
571href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
572causes huge link times (minutes instead of seconds) when building LLVM. We
573recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
574
Nick Lewycky87da07c2009-03-03 05:41:16 +0000[diff] [blame]575<p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained
Nick Lewycky829108e2009-02-25 06:29:47 +0000[diff] [blame]576<a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a>
577which causes intermittent failures when building LLVM with position independent
Nick Lewycky87da07c2009-03-03 05:41:16 +0000[diff] [blame]578code. The symptom is an error about cyclic dependencies. We recommend
579upgrading to a newer version of Gold.</p>
Nick Lewycky829108e2009-02-25 06:29:47 +0000[diff] [blame]580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]581</div>
582
583
584
585<!-- *********************************************************************** -->
586<div class="doc_section">
587 <a name="starting"><b>Getting Started with LLVM</b></a>
588</div>
589<!-- *********************************************************************** -->
590
591<div class="doc_text">
592
593<p>The remainder of this guide is meant to get you up and running with
594LLVM and to give you some basic information about the LLVM environment.</p>
595
596<p>The later sections of this guide describe the <a
597href="#layout">general layout</a> of the the LLVM source tree, a <a
598href="#tutorial">simple example</a> using the LLVM tool chain, and <a
599href="#links">links</a> to find more information about LLVM or to get
600help via e-mail.</p>
601</div>
602
603<!-- ======================================================================= -->
604<div class="doc_subsection">
605 <a name="terminology">Terminology and Notation</a>
606</div>
607
608<div class="doc_text">
609
610<p>Throughout this manual, the following names are used to denote paths
611specific to the local system and working environment. <i>These are not
612environment variables you need to set but just strings used in the rest
613of this document below</i>. In any of the examples below, simply replace
614each of these names with the appropriate pathname on your local system.
615All these paths are absolute:</p>
616
617<dl>
618 <dt>SRC_ROOT
619 <dd>
620 This is the top level directory of the LLVM source tree.
621 <br><br>
622
623 <dt>OBJ_ROOT
624 <dd>
625 This is the top level directory of the LLVM object tree (i.e. the
626 tree where object files and compiled programs will be placed. It
627 can be the same as SRC_ROOT).
628 <br><br>
629
630 <dt>LLVMGCCDIR
631 <dd>
632 This is where the LLVM GCC Front End is installed.
633 <p>
634 For the pre-built GCC front end binaries, the LLVMGCCDIR is
635 <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
636</dl>
637
638</div>
639
640<!-- ======================================================================= -->
641<div class="doc_subsection">
642 <a name="environment">Setting Up Your Environment</a>
643</div>
644
645<div class="doc_text">
646
647<p>
648In order to compile and use LLVM, you may need to set some environment
649variables.
650
651<dl>
652 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
653 <dd>[Optional] This environment variable helps LLVM linking tools find the
654 locations of your bitcode libraries. It is provided only as a
655 convenience since you can specify the paths using the -L options of the
656 tools and the C/C++ front-end will automatically use the bitcode files
657 installed in its
658 <tt>lib</tt> directory.</dd>
659</dl>
660
661</div>
662
663<!-- ======================================================================= -->
664<div class="doc_subsection">
665 <a name="unpack">Unpacking the LLVM Archives</a>
666</div>
667
668<div class="doc_text">
669
670<p>
671If you have the LLVM distribution, you will need to unpack it before you
672can begin to compile it. LLVM is distributed as a set of two files: the LLVM
673suite and the LLVM GCC front end compiled for your platform. There is an
674additional test suite that is optional. Each file is a TAR archive that is
675compressed with the gzip program.
676</p>
677
678<p>The files are as follows, with <em>x.y</em> marking the version number:
679<dl>
680 <dt><tt>llvm-x.y.tar.gz</tt></dt>
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]681 <dd>Source release for the LLVM libraries and tools.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]682
683 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
684 <dd>Source release for the LLVM test suite.</dd>
685
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]686 <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt>
687 <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]688 directory for build instructions.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]690 <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt>
691 <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]692
693</dl>
694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]695</div>
696
697<!-- ======================================================================= -->
698<div class="doc_subsection">
699 <a name="checkout">Checkout LLVM from Subversion</a>
700</div>
701
702<div class="doc_text">
703
704<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]705the 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]706follows:</p>
707
708<ul>
709 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
710 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
711 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
712 llvm</tt></li>
713</ul>
714
715
716<p>This will create an '<tt>llvm</tt>' directory in the current
717directory and fully populate it with the LLVM source code, Makefiles,
718test directories, and local copies of documentation files.</p>
719
720<p>If you want to get a specific release (as opposed to the most recent
721revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
722'<tt>trunk</tt>'). The following releases are located in the following
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]723subdirectories of the '<tt>tags</tt>' directory:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]724
725<ul>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]726<li>Release 2.5: <b>RELEASE_25</b></li>
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]727<li>Release 2.4: <b>RELEASE_24</b></li>
Tanya Lattner9eb3be52008-06-09 06:02:09 +0000[diff] [blame]728<li>Release 2.3: <b>RELEASE_23</b></li>
Tanya Lattner60030782008-02-12 02:42:55 +0000[diff] [blame]729<li>Release 2.2: <b>RELEASE_22</b></li>
Tanya Lattner2fad5b02007-09-28 22:50:54 +0000[diff] [blame]730<li>Release 2.1: <b>RELEASE_21</b></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]731<li>Release 2.0: <b>RELEASE_20</b></li>
732<li>Release 1.9: <b>RELEASE_19</b></li>
733<li>Release 1.8: <b>RELEASE_18</b></li>
734<li>Release 1.7: <b>RELEASE_17</b></li>
735<li>Release 1.6: <b>RELEASE_16</b></li>
736<li>Release 1.5: <b>RELEASE_15</b></li>
737<li>Release 1.4: <b>RELEASE_14</b></li>
738<li>Release 1.3: <b>RELEASE_13</b></li>
739<li>Release 1.2: <b>RELEASE_12</b></li>
740<li>Release 1.1: <b>RELEASE_11</b></li>
741<li>Release 1.0: <b>RELEASE_1</b></li>
742</ul>
743
744<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
745you get it from the Subversion repository:</p>
746
747<div class="doc_code">
748<pre>
749% cd llvm/projects
750% svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
751</pre>
752</div>
753
754<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
755configured by the LLVM configure script as well as automatically updated when
756you run <tt>svn update</tt>.</p>
757
758<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]759and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]760instructions</a> to successfully get and build the LLVM GCC front-end.</p>
761
762</div>
763
764<!-- ======================================================================= -->
765<div class="doc_subsection">
766 <a name="installcf">Install the GCC Front End</a>
767</div>
768
769<div class="doc_text">
770
771<p>Before configuring and compiling the LLVM suite, you can optionally extract the
772LLVM GCC front end from the binary distribution. It is used for running the
773llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]774<a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]775main LLVM repository.</p>
776
777<p>To install the GCC front end, do the following:</p>
778
779<ol>
780 <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]781 <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]782 -</tt></li>
783</ol>
784
785<p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
786llvm-g++ to some directory in your path. When you configure LLVM, it will
787automatically detect llvm-gcc's presence (if it is in your path) enabling its
788use in llvm-test. Note that you can always build or install llvm-gcc at any
789pointer after building the main LLVM repository: just reconfigure llvm and
790llvm-test will pick it up.
791</p>
792
793<p>The binary versions of the GCC front end may not suit all of your needs. For
794example, the binary distribution may include an old version of a system header
795file, not "fix" a header file that needs to be fixed for GCC, or it may be
796linked with libraries not available on your system.</p>
797
798<p>In cases like these, you may want to try <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]799href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]800much easier now than it was in the past.</p>
801
802</div>
803
804<!-- ======================================================================= -->
805<div class="doc_subsection">
806 <a name="config">Local LLVM Configuration</a>
807</div>
808
809<div class="doc_text">
810
811 <p>Once checked out from the Subversion repository, the LLVM suite source
812 code must be
813configured via the <tt>configure</tt> script. This script sets variables in the
814various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
815<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
816the Makefiles needed to begin building LLVM.</p>
817
818<p>The following environment variables are used by the <tt>configure</tt>
819script to configure the build system:</p>
820
821<table summary="LLVM configure script environment variables">
822 <tr><th>Variable</th><th>Purpose</th></tr>
823 <tr>
824 <td>CC</td>
825 <td>Tells <tt>configure</tt> which C compiler to use. By default,
826 <tt>configure</tt> will look for the first GCC C compiler in
827 <tt>PATH</tt>. Use this variable to override
828 <tt>configure</tt>'s default behavior.</td>
829 </tr>
830 <tr>
831 <td>CXX</td>
832 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
833 <tt>configure</tt> will look for the first GCC C++ compiler in
834 <tt>PATH</tt>. Use this variable to override
835 <tt>configure</tt>'s default behavior.</td>
836 </tr>
837</table>
838
839<p>The following options can be used to set or enable LLVM specific options:</p>
840
841<dl>
842 <dt><i>--with-llvmgccdir</i></dt>
843 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
844 The value of this option should specify the full pathname of the C/C++ Front
845 End to be used. If this option is not provided, the PATH will be searched for
846 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
847 be inferred from the path found. If the option is not given, and no llvm-gcc
848 can be found in the path then a warning will be produced by
849 <tt>configure</tt> indicating this situation. LLVM may still be built with
850 the <tt>tools-only</tt> target but attempting to build the runtime libraries
851 will fail as these libraries require llvm-gcc and llvm-g++. See
852 <a href="#installcf">Install the GCC Front End</a> for details on installing
853 the C/C++ Front End. See
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]854 <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]855 for details on building the C/C++ Front End.</dd>
856 <dt><i>--with-tclinclude</i></dt>
857 <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
858 found. Use this if you have multiple tcl installations on your machine and you
859 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
860 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
861 option, the LLVM configure script will search for the tcl 8.4 and 8.3
862 releases.
863 <br><br>
864 </dd>
865 <dt><i>--enable-optimized</i></dt>
866 <dd>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]867 Enables optimized compilation (debugging symbols are removed
868 and GCC optimization flags are enabled). Note that this is the default
869 setting if you are using the LLVM distribution. The default behavior
870 of an Subversion checkout is to use an unoptimized build (also known as a
871 debug build).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]872 <br><br>
873 </dd>
874 <dt><i>--enable-debug-runtime</i></dt>
875 <dd>
876 Enables debug symbols in the runtime libraries. The default is to strip
877 debug symbols from the runtime libraries.
878 </dd>
879 <dt><i>--enable-jit</i></dt>
880 <dd>
881 Compile the Just In Time (JIT) compiler functionality. This is not
882 available
883 on all platforms. The default is dependent on platform, so it is best
884 to explicitly enable it if you want it.
885 <br><br>
886 </dd>
887 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
888 <dd>Controls which targets will be built and linked into llc. The default
889 value for <tt>target_options</tt> is "all" which builds and links all
890 available targets. The value "host-only" can be specified to build only a
891 native compiler (no cross-compiler targets available). The "native" target is
892 selected as the target of the build host. You can also specify a comma
893 separated list of target names that you want available in llc. The target
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]894 names use all lower case. The current set of targets is: <br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
896 <br><br></dd>
897 <dt><i>--enable-doxygen</i></dt>
898 <dd>Look for the doxygen program and enable construction of doxygen based
899 documentation from the source code. This is disabled by default because
900 generating the documentation can take a long time and producess 100s of
901 megabytes of output.</dd>
902 <dt><i>--with-udis86</i></dt>
903 <dd>LLVM can use external disassembler library for various purposes (now it's
904 used only for examining code produced by JIT). This option will enable usage
905 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
906 bits) disassembler library.</dd>
907</dl>
908
909<p>To configure LLVM, follow these steps:</p>
910
911<ol>
912 <li><p>Change directory into the object root directory:</p>
913
914 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
915
916 <li><p>Run the <tt>configure</tt> script located in the LLVM source
917 tree:</p>
918
919 <div class="doc_code">
920 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
921 </div></li>
922</ol>
923
924</div>
925
926<!-- ======================================================================= -->
927<div class="doc_subsection">
928 <a name="compile">Compiling the LLVM Suite Source Code</a>
929</div>
930
931<div class="doc_text">
932
933<p>Once you have configured LLVM, you can build it. There are three types of
934builds:</p>
935
936<dl>
937 <dt>Debug Builds
938 <dd>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]939 These builds are the default when one is using an Subversion checkout and
940 types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was
941 used during configuration). The build system will compile the tools and
942 libraries with debugging information. To get a Debug Build using the
943 LLVM distribution the <tt>--disable-optimized</tt> option must be passed
944 to <tt>configure</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]945 <br><br>
946
947 <dt>Release (Optimized) Builds
948 <dd>
949 These builds are enabled with the <tt>--enable-optimized</tt> option to
950 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
951 <tt>gmake</tt> command line. For these builds, the build system will
952 compile the tools and libraries with GCC optimizations enabled and strip
953 debugging information from the libraries and executables it generates.
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]954 Note that Release Builds are default when using an LLVM distribution.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]955 <br><br>
956
957 <dt>Profile Builds
958 <dd>
959 These builds are for use with profiling. They compile profiling
960 information into the code for use with programs like <tt>gprof</tt>.
961 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
962 on the <tt>gmake</tt> command line.
963</dl>
964
965<p>Once you have LLVM configured, you can build it by entering the
966<i>OBJ_ROOT</i> directory and issuing the following command:</p>
967
968<div class="doc_code"><pre>% gmake</pre></div>
969
970<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
971are using a version of GCC that is known not to compile LLVM.</p>
972
973<p>
974If you have multiple processors in your machine, you may wish to use some of
975the parallel build options provided by GNU Make. For example, you could use the
976command:</p>
977
978<div class="doc_code"><pre>% gmake -j2</pre></div>
979
980<p>There are several special targets which are useful when working with the LLVM
981source code:</p>
982
983<dl>
984 <dt><tt>gmake clean</tt>
985 <dd>
986 Removes all files generated by the build. This includes object files,
987 generated C/C++ files, libraries, and executables.
988 <br><br>
989
990 <dt><tt>gmake dist-clean</tt>
991 <dd>
992 Removes everything that <tt>gmake clean</tt> does, but also removes files
993 generated by <tt>configure</tt>. It attempts to return the source tree to the
994 original state in which it was shipped.
995 <br><br>
996
997 <dt><tt>gmake install</tt>
998 <dd>
999 Installs LLVM header files, libraries, tools, and documentation in a
1000 hierarchy
1001 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
1002 defaults to <tt>/usr/local</tt>.
1003 <br><br>
1004
1005 <dt><tt>gmake -C runtime install-bytecode</tt>
1006 <dd>
1007 Assuming you built LLVM into $OBJDIR, when this command is run, it will
1008 install bitcode libraries into the GCC front end's bitcode library
1009 directory. If you need to update your bitcode libraries,
1010 this is the target to use once you've built them.
1011 <br><br>
1012</dl>
1013
1014<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
1015details on these <tt>make</tt> targets and descriptions of other targets
1016available.</p>
1017
1018<p>It is also possible to override default values from <tt>configure</tt> by
1019declaring variables on the command line. The following are some examples:</p>
1020
1021<dl>
1022 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1023 <dd>
1024 Perform a Release (Optimized) build.
1025 <br><br>
1026
1027 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1028 <dd>
1029 Perform a Release (Optimized) build without assertions enabled.
1030 <br><br>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]1031
1032 <dt><tt>gmake ENABLE_OPTIMIZED=0</tt>
1033 <dd>
1034 Perform a Debug build.
1035 <br><br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1036
1037 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1038 <dd>
1039 Perform a Profiling build.
1040 <br><br>
1041
1042 <dt><tt>gmake VERBOSE=1</tt>
1043 <dd>
1044 Print what <tt>gmake</tt> is doing on standard output.
1045 <br><br>
1046
1047 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1048 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1049 the standard output. This also implies <tt>VERBOSE=1</tt>.
1050 <br><br></dd>
1051</dl>
1052
1053<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1054it and any subdirectories that it contains. Entering any directory inside the
1055LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1056that directory that is out of date.</p>
1057
1058</div>
1059
1060<!-- ======================================================================= -->
1061<div class="doc_subsection">
1062 <a name="cross-compile">Cross-Compiling LLVM</a>
1063</div>
1064
1065<div class="doc_text">
Jim Grosbachc8c74362009-04-17 17:25:16 +0000[diff] [blame]1066 <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
1067 executables and libraries to be hosted on a platform different from the
1068 platform where they are build (a Canadian Cross build). To configure a
1069 cross-compile, supply the configure script with <tt>--build</tt> and
1070 <tt>--host</tt> options that are different. The values of these options must
1071 be legal target triples that your GCC compiler supports.</p>
1072
1073 <p>The result of such a build is executables that are not runnable on
1074 on the build host (--build option) but can be executed on the compile host
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1075 (--host option).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1076</div>
1077
1078<!-- ======================================================================= -->
1079<div class="doc_subsection">
1080 <a name="objfiles">The Location of LLVM Object Files</a>
1081</div>
1082
1083<div class="doc_text">
1084
1085<p>The LLVM build system is capable of sharing a single LLVM source tree among
1086several LLVM builds. Hence, it is possible to build LLVM for several different
1087platforms or configurations using the same source tree.</p>
1088
1089<p>This is accomplished in the typical autoconf manner:</p>
1090
1091<ul>
1092 <li><p>Change directory to where the LLVM object files should live:</p>
1093
1094 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1095
1096 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1097 directory:</p>
1098
1099 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1100</ul>
1101
1102<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1103named after the build type:</p>
1104
1105<dl>
1106 <dt>Debug Builds
1107 <dd>
1108 <dl>
1109 <dt>Tools
1110 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1111 <dt>Libraries
1112 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1113 </dl>
1114 <br><br>
1115
1116 <dt>Release Builds
1117 <dd>
1118 <dl>
1119 <dt>Tools
1120 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1121 <dt>Libraries
1122 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1123 </dl>
1124 <br><br>
1125
1126 <dt>Profile Builds
1127 <dd>
1128 <dl>
1129 <dt>Tools
1130 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1131 <dt>Libraries
1132 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1133 </dl>
1134</dl>
1135
1136</div>
1137
1138<!-- ======================================================================= -->
1139<div class="doc_subsection">
1140 <a name="optionalconfig">Optional Configuration Items</a>
1141</div>
1142
1143<div class="doc_text">
1144
1145<p>
1146If you're running on a Linux system that supports the "<a
1147href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1148module, and you have root access on the system, you can set your system up to
1149execute LLVM bitcode files directly. To do this, use commands like this (the
1150first command may not be required if you are already using the module):</p>
1151
1152<div class="doc_code">
1153<pre>
1154$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1155$ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1156$ chmod u+x hello.bc (if needed)
1157$ ./hello.bc
1158</pre>
1159</div>
1160
1161<p>
1162This allows you to execute LLVM bitcode files directly. Thanks to Jack
1163Cummings for pointing this out!
1164</p>
1165
1166</div>
1167
1168
1169<!-- *********************************************************************** -->
1170<div class="doc_section">
1171 <a name="layout"><b>Program Layout</b></a>
1172</div>
1173<!-- *********************************************************************** -->
1174
1175<div class="doc_text">
1176
1177<p>One useful source of information about the LLVM source base is the LLVM <a
1178href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1179href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1180The following is a brief introduction to code layout:</p>
1181
1182</div>
1183
1184<!-- ======================================================================= -->
1185<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1186<div class="doc_text">
1187 <p>This directory contains some simple examples of how to use the LLVM IR and
1188 JIT.</p>
1189</div>
1190
1191<!-- ======================================================================= -->
1192<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1193<div class="doc_text">
1194
1195<p>This directory contains public header files exported from the LLVM
1196library. The three main subdirectories of this directory are:</p>
1197
1198<dl>
1199 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1200 <dd>This directory contains all of the LLVM specific header files. This
1201 directory also has subdirectories for different portions of LLVM:
1202 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1203 etc...</dd>
1204
1205 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1206 <dd>This directory contains generic support libraries that are provided with
1207 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1208 and a Command Line option processing library store their header files here.
1209 </dd>
1210
1211 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1212 <dd>This directory contains header files configured by the <tt>configure</tt>
1213 script. They wrap "standard" UNIX and C header files. Source code can
1214 include these header files which automatically take care of the conditional
1215 #includes that the <tt>configure</tt> script generates.</dd>
1216</dl>
1217</div>
1218
1219<!-- ======================================================================= -->
1220<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1221<div class="doc_text">
1222
1223<p>This directory contains most of the source files of the LLVM system. In LLVM,
1224almost all code exists in libraries, making it very easy to share code among the
1225different <a href="#tools">tools</a>.</p>
1226
1227<dl>
1228 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1229 <dd> This directory holds the core LLVM source files that implement core
1230 classes like Instruction and BasicBlock.</dd>
1231
1232 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1233 <dd>This directory holds the source code for the LLVM assembly language parser
1234 library.</dd>
1235
1236 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1237 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1238
1239 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1240 different program analyses, such as Dominator Information, Call Graphs,
1241 Induction Variables, Interval Identification, Natural Loop Identification,
1242 etc.</dd>
1243
1244 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1245 <dd> This directory contains the source code for the LLVM to LLVM program
1246 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1247 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1248 Elimination, and many others.</dd>
1249
1250 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1251 <dd> This directory contains files that describe various target architectures
1252 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1253 directory holds the X86 machine description while
1254 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1255
1256 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1257 <dd> This directory contains the major parts of the code generator: Instruction
1258 Selector, Instruction Scheduling, and Register Allocation.</dd>
1259
1260 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1261 <dd> This directory contains the source level debugger library that makes
1262 it possible to instrument LLVM programs so that a debugger could identify
1263 source code locations at which the program is executing.</dd>
1264
1265 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1266 <dd> This directory contains libraries for executing LLVM bitcode directly
1267 at runtime in both interpreted and JIT compiled fashions.</dd>
1268
1269 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1270 <dd> This directory contains the source code that corresponds to the header
1271 files located in <tt>llvm/include/Support/</tt>.</dd>
1272
1273 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1274 <dd>This directory contains the operating system abstraction layer that
1275 shields LLVM from platform-specific coding.</dd>
1276</dl>
1277
1278</div>
1279
1280<!-- ======================================================================= -->
1281<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1282<div class="doc_text">
1283 <p>This directory contains projects that are not strictly part of LLVM but are
1284 shipped with LLVM. This is also the directory where you should create your own
1285 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
Chris Lattneraf1df782008-08-11 06:13:31 +0000[diff] [blame]1286 to set up your own project.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1287</div>
1288
1289<!-- ======================================================================= -->
1290<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1291<div class="doc_text">
1292
1293<p>This directory contains libraries which are compiled into LLVM bitcode and
1294used when linking programs with the GCC front end. Most of these libraries are
1295skeleton versions of real libraries; for example, libc is a stripped down
1296version of glibc.</p>
1297
1298<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1299end to compile.</p>
1300
1301</div>
1302
1303<!-- ======================================================================= -->
1304<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1305<div class="doc_text">
1306 <p>This directory contains feature and regression tests and other basic sanity
1307 checks on the LLVM infrastructure. These are intended to run quickly and cover
1308 a lot of territory without being exhaustive.</p>
1309</div>
1310
1311<!-- ======================================================================= -->
1312<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1313<div class="doc_text">
1314 <p>This is not a directory in the normal llvm module; it is a separate
1315 Subversion
1316 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1317 This
1318 module contains a comprehensive correctness, performance, and benchmarking
1319 test
1320 suite for LLVM. It is a separate Subversion module because not every LLVM
1321 user is
1322 interested in downloading or building such a comprehensive test suite. For
1323 further details on this test suite, please see the
1324 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1325</div>
1326
1327<!-- ======================================================================= -->
1328<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1329<div class="doc_text">
1330
1331<p>The <b>tools</b> directory contains the executables built out of the
1332libraries above, which form the main part of the user interface. You can
1333always get help for a tool by typing <tt>tool_name --help</tt>. The
1334following is a brief introduction to the most important tools. More detailed
1335information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1336
1337<dl>
1338
1339 <dt><tt><b>bugpoint</b></tt></dt>
1340 <dd><tt>bugpoint</tt> is used to debug
1341 optimization passes or code generation backends by narrowing down the
1342 given test case to the minimum number of passes and/or instructions that
1343 still cause a problem, whether it is a crash or miscompilation. See <a
1344 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1345 on using <tt>bugpoint</tt>.</dd>
1346
1347 <dt><tt><b>llvmc</b></tt></dt>
1348 <dd>The LLVM Compiler Driver. This program can
1349 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1350 pre-processing, translation, optimization, assembly, and linking of programs
1351 all from one command line. <tt>llvmc</tt> also takes care of processing the
1352 dependent libraries found in bitcode. This reduces the need to get the
1353 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1354 note that this tool, while functional, is still experimental and not feature
1355 complete.</dd>
1356
1357 <dt><tt><b>llvm-ar</b></tt></dt>
1358 <dd>The archiver produces an archive containing
1359 the given LLVM bitcode files, optionally with an index for faster
1360 lookup.</dd>
1361
1362 <dt><tt><b>llvm-as</b></tt></dt>
1363 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1364 bitcode.</dd>
1365
1366 <dt><tt><b>llvm-dis</b></tt></dt>
1367 <dd>The disassembler transforms the LLVM bitcode to human readable
1368 LLVM assembly.</dd>
1369
1370 <dt><tt><b>llvm-ld</b></tt></dt>
1371 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1372 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1373 optimizations and allows optimization modules to be loaded and run so that
1374 language specific optimizations can be applied at link time.</dd>
1375
1376 <dt><tt><b>llvm-link</b></tt></dt>
1377 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1378 a single program.</dd>
1379
1380 <dt><tt><b>lli</b></tt></dt>
1381 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +0000[diff] [blame]1382 can directly execute LLVM bitcode (although very slowly...). For architectures
1383 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1384 will function as a Just-In-Time compiler (if the functionality was compiled
1385 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1386
1387 <dt><tt><b>llc</b></tt></dt>
1388 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1389 translates LLVM bitcode to a native code assembly file or to C code (with
1390 the -march=c option).</dd>
1391
1392 <dt><tt><b>llvm-gcc</b></tt></dt>
1393 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1394 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1395 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1396 usual machine code output. It works just like any other GCC compiler,
1397 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1398 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1399 separate Subversion module.</dd>
1400
1401 <dt><tt><b>opt</b></tt></dt>
1402 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1403 transformations (which are specified on the command line), and then outputs
1404 the resultant bitcode. The '<tt>opt --help</tt>' command is a good way to
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]1405 get a list of the program transformations available in LLVM.<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1406 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1407 LLVM bitcode file and print out the results. It is primarily useful for
1408 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1409</dl>
1410</div>
1411
1412<!-- ======================================================================= -->
1413<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1414<div class="doc_text">
1415
1416<p>This directory contains utilities for working with LLVM source code, and some
1417of the utilities are actually required as part of the build process because they
1418are code generators for parts of LLVM infrastructure.</p>
1419
1420<dl>
1421 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1422 that finds differences between code that LLC generates and code that LLI
1423 generates. This is a useful tool if you are debugging one of them,
1424 assuming that the other generates correct output. For the full user
1425 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1426
1427 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1428 syntax-highlighting files which will work with Emacs and XEmacs editors,
1429 providing syntax highlighting support for LLVM assembly files and TableGen
1430 description files. For information on how to use the syntax files, consult
1431 the <tt>README</tt> file in that directory.<br><br>
1432
1433 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1434 and outputs all non-generated source files, which is useful if one wishes
1435 to do a lot of development across directories and does not want to
1436 individually find each file. One way to use it is to run, for example:
1437 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1438 tree.<br><br>
1439
1440 <dt><tt><b>llvmgrep</b></tt></dt>
1441 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1442 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1443 line. This is a very efficient way of searching the source base for a
1444 particular regular expression.</dd>
1445
1446 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1447 files in the current directory and then compiles and links the tool that
1448 is the first argument. For example, assuming you are in the directory
1449 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1450 simply running <tt>makellvm llc</tt> will make a build of the current
1451 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1452 causing a re-linking of LLC.<br><br>
1453
1454 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1455 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1456 cron script to generate nightly status reports of the functionality of
1457 tools, and the results can be seen by following the appropriate link on
1458 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1459
1460 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1461 the tool used to generate register descriptions, instruction set
1462 descriptions, and even assemblers from common TableGen description
1463 files.<br><br>
1464
1465 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1466 syntax-highlighting files which will work with the VIM editor, providing
1467 syntax highlighting support for LLVM assembly files and TableGen
1468 description files. For information on how to use the syntax files, consult
1469 the <tt>README</tt> file in that directory.<br><br>
1470
1471</dl>
1472
1473</div>
1474
1475<!-- ======================================================================= -->
1476<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1477<div class="doc_text">
1478 <p>This directory contains build scripts and project files for use with
1479 Visual C++. This allows developers on Windows to build LLVM without the need
1480 for Cygwin. The contents of this directory should be considered experimental
1481 at this time.
1482 </p>
1483</div>
1484<!-- *********************************************************************** -->
1485<div class="doc_section">
1486 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1487</div>
1488<!-- *********************************************************************** -->
1489
1490<div class="doc_text">
1491<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
Chris Lattnere6099642009-04-10 15:38:51 +0000[diff] [blame]1492so we only include instructions for llvm-gcc4.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1493</p>
1494
1495<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1496from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1497create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1498the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1499<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1500output.</p>
1501</div>
1502
1503<!-- ======================================================================= -->
1504<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1505
1506<div class="doc_text">
1507
1508<ol>
1509 <li><p>First, create a simple C file, name it 'hello.c':</p>
1510
1511<div class="doc_code">
1512<pre>
1513#include &lt;stdio.h&gt;
1514
1515int main() {
1516 printf("hello world\n");
1517 return 0;
1518}
1519</pre></div></li>
1520
1521 <li><p>Next, compile the C file into a native executable:</p>
1522
1523 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1524
1525 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1526 -c arguments work as usual (producing a native .s or .o file,
1527 respectively).</p></li>
1528
1529 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1530
1531 <div class="doc_code">
1532 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1533
1534 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1535 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1536 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1537 the bitcode file.</p>
1538
1539 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1540 </p></li>
1541
1542 <li><p>Run the program in both forms. To run the program, use:</p>
1543
1544 <div class="doc_code"><pre>% ./hello</pre></div>
1545
1546 <p>and</p>
1547
1548 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1549
1550 <p>The second examples shows how to invoke the LLVM JIT, <a
1551 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1552
1553 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1554 code:</p>
1555
1556<div class="doc_code">
1557<pre>llvm-dis &lt; hello.bc | less</pre>
1558</div></li>
1559
1560 <li><p>Compile the program to native assembly using the LLC code
1561 generator:</p>
1562
1563 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1564
1565 <li><p>Assemble the native assembly language file into a program:</p>
1566
1567<div class="doc_code">
1568<pre>
1569<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1570
1571<b>Others:</b> % gcc hello.s -o hello.native
1572</pre>
1573</div></li>
1574
1575 <li><p>Execute the native code program:</p>
1576
1577 <div class="doc_code"><pre>% ./hello.native</pre></div>
1578
1579 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1580 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1581 </li>
1582
1583</ol>
1584
1585</div>
1586
1587
1588<!-- *********************************************************************** -->
1589<div class="doc_section">
1590 <a name="problems">Common Problems</a>
1591</div>
1592<!-- *********************************************************************** -->
1593
1594<div class="doc_text">
1595
1596<p>If you are having problems building or using LLVM, or if you have any other
1597general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1598Asked Questions</a> page.</p>
1599
1600</div>
1601
1602<!-- *********************************************************************** -->
1603<div class="doc_section">
1604 <a name="links">Links</a>
1605</div>
1606<!-- *********************************************************************** -->
1607
1608<div class="doc_text">
1609
Bill Wendling08f49b92008-07-22 01:10:25 +0000[diff] [blame]1610<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]1611some simple things... there are many more interesting and complicated things
1612that you can do that aren't documented here (but we'll gladly accept a patch
1613if you want to write something up!). For more information about LLVM, check
1614out:</p>
1615
1616<ul>
1617 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1618 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1619 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1620 that Uses LLVM</a></li>
1621</ul>
1622
1623</div>
1624
1625<!-- *********************************************************************** -->
1626
1627<hr>
1628<address>
1629 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]1630 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1631 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]1632 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]1633
1634 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1635 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1636 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
1637 Last modified: $Date$
1638</address>
1639</body>
1640</html>