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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>
219 <td>Linux</td>
220 <td>x86<sup><a href="#pf_1">1</a></sup></td>
221 <td>GCC</td>
222</tr>
223<tr>
224 <td>Solaris</td>
225 <td>V9 (Ultrasparc)</td>
226 <td>GCC</td>
227</tr>
228<tr>
229 <td>FreeBSD</td>
230 <td>x86<sup><a href="#pf_1">1</a></sup></td>
231 <td>GCC</td>
232</tr>
233<tr>
234 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
235 <td>PowerPC</td>
236 <td>GCC</td>
237</tr>
238<tr>
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]239 <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]240 <td>x86</td>
241 <td>GCC</td>
242
243</tr>
244<tr>
245 <td>Cygwin/Win32</td>
246 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a></sup></td>
247 <td>GCC 3.4.X, binutils 2.15</td>
248</tr>
249<tr>
250 <td>MinGW/Win32</td>
251 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,<a href="#pf_8">8</a></sup></td>
252 <td>GCC 3.4.X, binutils 2.15</td>
253</tr>
254<tr>
255 <td>Linux</td>
Dan Gohman99fc2442008-11-13 19:07:07 +0000[diff] [blame]256 <td>amd64</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]257 <td>GCC</td>
258</tr>
259</table>
260
261<p>LLVM has partial support for the following platforms:</p>
262
263<table summary="LLVM partial platform support">
264<tr>
265 <th>OS</th>
266 <th>Arch</th>
267 <th>Compilers</th>
268</tr>
269<tr>
270 <td>Windows</td>
271 <td>x86<sup><a href="#pf_1">1</a></sup></td>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]272 <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]273<tr>
274 <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
275 <td>PowerPC</td>
276 <td>GCC</td>
277</tr>
278<tr>
279 <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
280 <td>PowerPC</td>
281 <td>GCC</td>
282</tr>
283
284<tr>
285 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
286 <td>Alpha</td>
287 <td>GCC</td>
288</tr>
289<tr>
290 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
291 <td>Itanium (IA-64)</td>
292 <td>GCC</td>
293</tr>
294<tr>
295 <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
296 <td>Itanium (IA-64)</td>
297 <td>HP aCC</td>
298</tr>
299</table>
300
301<p><b>Notes:</b></p>
302
303<div class="doc_notes">
304<ol>
305<li><a name="pf_1">Code generation supported for Pentium processors and
306up</a></li>
307<li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
308<li><a name="pf_3">No native code generation</a></li>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]309<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]310<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]311<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]312<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
313<li><a name="pf_8">Binutils</a> up to post-2.17 has bug in bfd/cofflink.c
314 preventing LLVM from building correctly. Several workarounds have been
315 introduced into LLVM build system, but the bug can occur anytime in the
316 future. We highly recommend that you rebuild your current binutils with the
317 patch from <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=2659">
318 Binutils bugzilla</a>, if it wasn't already applied.</li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]319<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]320 internal LLVM assert messages when compiled for Release at optimization
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]321 levels greater than 0 (i.e., <i>"-O1"</i> and higher).
322 Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]323 if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]324</ol>
325</div>
326
327<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
328mode, depending on the system (it is so large because of all the debugging
329information and the fact that the libraries are statically linked into multiple
Chris Lattner15aeb9a2009-04-25 22:08:52 +0000[diff] [blame^]330tools). If you do not need many of the tools and you are space-conscious, you
331can pass <tt>ONLY_TOOLS="tools you need"</tt> to make. The Release build
332requires considerably less space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]333
334<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
335guaranteed to do so. If compilation is successful, the LLVM utilities should be
336able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
337generation should work as well, although the generated native code may not work
338on your platform.</p>
339
340<p>The GCC front end is not very portable at the moment. If you want to get it
341to work on another platform, you can download a copy of the source and <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]342href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]343
344</div>
345
346<!-- ======================================================================= -->
347<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
348<div class="doc_text">
349 <p>Compiling LLVM requires that you have several software packages
350 installed. The table below lists those required packages. The Package column
351 is the usual name for the software package that LLVM depends on. The Version
352 column provides "known to work" versions of the package. The Notes column
353 describes how LLVM uses the package and provides other details.</p>
354 <table summary="Packages required to compile LLVM">
355 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
356
357 <tr>
358 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
359 <td>3.79, 3.79.1</td>
360 <td>Makefile/build processor</td>
361 </tr>
362
363 <tr>
364 <td><a href="http://gcc.gnu.org">GCC</a></td>
365 <td>3.4.2</td>
366 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
367 </tr>
368
369 <tr>
370 <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
371 <td>4.5</td>
372 <td>For building the CFE</td>
373 </tr>
374
375 <tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]376 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
377 <td>&ge;1.3</td>
378 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
379 </tr>
380
381 <tr>
382 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
383 <td>1.4.2</td>
384 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
385 </tr>
386
387 <tr>
388 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
389 <td>8.3, 8.4</td>
390 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
391 </tr>
392
393 <tr>
394 <td><a href="http://expect.nist.gov/">expect</a></td>
395 <td>5.38.0</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.perl.com/download.csp">perl</a></td>
401 <td>&ge;5.6.0</td>
402 <td>Nightly tester, utilities</td>
403 </tr>
404
405 <tr>
406 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
407 <td>1.4</td>
408 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
409 </tr>
410
411 <tr>
412 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
413 <td>2.59</td>
414 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
415 </tr>
416
417 <tr>
418 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
419 <td>1.9.2</td>
420 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
421 </tr>
422
423 <tr>
424 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
425 <td>1.5.10</td>
426 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
427 </tr>
428
429 </table>
430
431 <p><b>Notes:</b></p>
432 <div class="doc_notes">
433 <ol>
434 <li><a name="sf1">Only the C and C++ languages are needed so there's no
435 need to build the other languages for LLVM's purposes.</a> See
436 <a href="#brokengcc">below</a> for specific version info.</li>
437 <li><a name="sf2">You only need Subversion if you intend to build from the
438 latest LLVM sources. If you're working from a release distribution, you
439 don't need Subversion.</a></li>
440 <li><a name="sf3">Only needed if you want to run the automated test
441 suite in the <tt>llvm/test</tt> directory.</a></li>
442 <li><a name="sf4">If you want to make changes to the configure scripts,
443 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
444 or higher). You will also need automake (1.9.2). We only use aclocal
445 from that package.</a></li>
446 </ol>
447 </div>
448
449 <p>Additionally, your compilation host is expected to have the usual
450 plethora of Unix utilities. Specifically:</p>
451 <ul>
452 <li><b>ar</b> - archive library builder</li>
453 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
454 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
455 <li><b>chmod</b> - change permissions on a file</li>
456 <li><b>cat</b> - output concatenation utility</li>
457 <li><b>cp</b> - copy files</li>
458 <li><b>date</b> - print the current date/time </li>
459 <li><b>echo</b> - print to standard output</li>
460 <li><b>egrep</b> - extended regular expression search utility</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]461 <li><b>find</b> - find files/dirs in a file system</li>
462 <li><b>grep</b> - regular expression search utility</li>
463 <li><b>gzip*</b> - gzip command for distribution generation</li>
464 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
465 <li><b>install</b> - install directories/files </li>
466 <li><b>mkdir</b> - create a directory</li>
467 <li><b>mv</b> - move (rename) files</li>
468 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
469 <li><b>rm</b> - remove (delete) files and directories</li>
470 <li><b>sed</b> - stream editor for transforming output</li>
471 <li><b>sh</b> - Bourne shell for make build scripts</li>
472 <li><b>tar</b> - tape archive for distribution generation</li>
473 <li><b>test</b> - test things in file system</li>
474 <li><b>unzip*</b> - unzip command for distribution checking</li>
475 <li><b>zip*</b> - zip command for distribution generation</li>
476 </ul>
477</div>
478
479<!-- ======================================================================= -->
480<div class="doc_subsection">
481 <a name="brokengcc">Broken versions of GCC and other tools</a>
482</div>
483
484<div class="doc_text">
485
486<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
487bugs in the compiler. In particular, several versions of GCC crash when trying
488to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
489successfully with them (however, see important notes below). Other versions
490of GCC will probably work as well. GCC versions listed
491here are known to not work. If you are using one of these versions, please try
492to upgrade your GCC to something more recent. If you run into a problem with a
493version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
494us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
495of GCC you are using.
496</p>
497
498<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
499problems in the STL that effectively prevent it from compiling LLVM.
500</p>
501
Chris Lattner76bb5302008-02-13 17:50:24 +0000[diff] [blame]502<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
503a bogus template error. This was fixed in later GCCs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]504
505<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
506href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
507the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
508
509<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]510 Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]511 to a newer version</a> if possible.</p>
512<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
513 possibly others) does not compile LLVM correctly (it appears that exception
514 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
515 to a newer version of GCC.</p>
516<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
517 code generator, causing an infinite loop in the llvm-gcc build when built
518 with optimizations enabled (i.e. a release build).</p>
519<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
520 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
521 correctly compiles LLVM at -O2. A work around is to build release LLVM
522 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
523<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
524 miscompiles portions of LLVM</a>.</p>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]525<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
526 when building with optimizations enabled. It appears to work with
527 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
528 build.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]529<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
530 miscompile LLVM.</p>
531<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
532 default with ENABLE_OPTIMIZED=1. To work around this, build with
533 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
534<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
535 compiling some files. At the time of this writing, GCC mainline (4.2)
536 did not share the problem.</p>
537<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
538 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
539 code. LLVM will appear to mostly work but will be buggy, e.g. failing
540 portions of its testsuite.</p>
541<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
542platforms compiling md5.c gets a mangled constant.</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000[diff] [blame]543<p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
544to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
545about symbols remaining in the table on destruction.</p>
Nuno Lopesfc375a62008-12-10 16:11:10 +0000[diff] [blame]546<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]547as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000[diff] [blame]548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]549<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
550long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
551defined in a discarded section. You can safely ignore these messages as they are
552erroneous and the linkage is correct. These messages disappear using ld
5532.17.</p>
554
555<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
556href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
557causes huge link times (minutes instead of seconds) when building LLVM. We
558recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
559
Nick Lewycky87da07c2009-03-03 05:41:16 +0000[diff] [blame]560<p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained
Nick Lewycky829108e2009-02-25 06:29:47 +0000[diff] [blame]561<a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a>
562which causes intermittent failures when building LLVM with position independent
Nick Lewycky87da07c2009-03-03 05:41:16 +0000[diff] [blame]563code. The symptom is an error about cyclic dependencies. We recommend
564upgrading to a newer version of Gold.</p>
Nick Lewycky829108e2009-02-25 06:29:47 +0000[diff] [blame]565
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]566</div>
567
568
569
570<!-- *********************************************************************** -->
571<div class="doc_section">
572 <a name="starting"><b>Getting Started with LLVM</b></a>
573</div>
574<!-- *********************************************************************** -->
575
576<div class="doc_text">
577
578<p>The remainder of this guide is meant to get you up and running with
579LLVM and to give you some basic information about the LLVM environment.</p>
580
581<p>The later sections of this guide describe the <a
582href="#layout">general layout</a> of the the LLVM source tree, a <a
583href="#tutorial">simple example</a> using the LLVM tool chain, and <a
584href="#links">links</a> to find more information about LLVM or to get
585help via e-mail.</p>
586</div>
587
588<!-- ======================================================================= -->
589<div class="doc_subsection">
590 <a name="terminology">Terminology and Notation</a>
591</div>
592
593<div class="doc_text">
594
595<p>Throughout this manual, the following names are used to denote paths
596specific to the local system and working environment. <i>These are not
597environment variables you need to set but just strings used in the rest
598of this document below</i>. In any of the examples below, simply replace
599each of these names with the appropriate pathname on your local system.
600All these paths are absolute:</p>
601
602<dl>
603 <dt>SRC_ROOT
604 <dd>
605 This is the top level directory of the LLVM source tree.
606 <br><br>
607
608 <dt>OBJ_ROOT
609 <dd>
610 This is the top level directory of the LLVM object tree (i.e. the
611 tree where object files and compiled programs will be placed. It
612 can be the same as SRC_ROOT).
613 <br><br>
614
615 <dt>LLVMGCCDIR
616 <dd>
617 This is where the LLVM GCC Front End is installed.
618 <p>
619 For the pre-built GCC front end binaries, the LLVMGCCDIR is
620 <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
621</dl>
622
623</div>
624
625<!-- ======================================================================= -->
626<div class="doc_subsection">
627 <a name="environment">Setting Up Your Environment</a>
628</div>
629
630<div class="doc_text">
631
632<p>
633In order to compile and use LLVM, you may need to set some environment
634variables.
635
636<dl>
637 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
638 <dd>[Optional] This environment variable helps LLVM linking tools find the
639 locations of your bitcode libraries. It is provided only as a
640 convenience since you can specify the paths using the -L options of the
641 tools and the C/C++ front-end will automatically use the bitcode files
642 installed in its
643 <tt>lib</tt> directory.</dd>
644</dl>
645
646</div>
647
648<!-- ======================================================================= -->
649<div class="doc_subsection">
650 <a name="unpack">Unpacking the LLVM Archives</a>
651</div>
652
653<div class="doc_text">
654
655<p>
656If you have the LLVM distribution, you will need to unpack it before you
657can begin to compile it. LLVM is distributed as a set of two files: the LLVM
658suite and the LLVM GCC front end compiled for your platform. There is an
659additional test suite that is optional. Each file is a TAR archive that is
660compressed with the gzip program.
661</p>
662
663<p>The files are as follows, with <em>x.y</em> marking the version number:
664<dl>
665 <dt><tt>llvm-x.y.tar.gz</tt></dt>
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]666 <dd>Source release for the LLVM libraries and tools.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]667
668 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
669 <dd>Source release for the LLVM test suite.</dd>
670
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]671 <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt>
672 <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]673 directory for build instructions.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]674
Misha Brukman313db032008-12-29 19:38:58 +0000[diff] [blame]675 <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt>
676 <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]677
678</dl>
679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]680</div>
681
682<!-- ======================================================================= -->
683<div class="doc_subsection">
684 <a name="checkout">Checkout LLVM from Subversion</a>
685</div>
686
687<div class="doc_text">
688
689<p>If you have access to our Subversion repository, you can get a fresh copy of
690the entire source code. All you need to do is check it out from Subvresion as
691follows:</p>
692
693<ul>
694 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
695 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
696 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
697 llvm</tt></li>
698</ul>
699
700
701<p>This will create an '<tt>llvm</tt>' directory in the current
702directory and fully populate it with the LLVM source code, Makefiles,
703test directories, and local copies of documentation files.</p>
704
705<p>If you want to get a specific release (as opposed to the most recent
706revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
707'<tt>trunk</tt>'). The following releases are located in the following
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]708subdirectories of the '<tt>tags</tt>' directory:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]709
710<ul>
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]711<li>Release 2.4: <b>RELEASE_24</b></li>
Tanya Lattner9eb3be52008-06-09 06:02:09 +0000[diff] [blame]712<li>Release 2.3: <b>RELEASE_23</b></li>
Tanya Lattner60030782008-02-12 02:42:55 +0000[diff] [blame]713<li>Release 2.2: <b>RELEASE_22</b></li>
Tanya Lattner2fad5b02007-09-28 22:50:54 +0000[diff] [blame]714<li>Release 2.1: <b>RELEASE_21</b></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]715<li>Release 2.0: <b>RELEASE_20</b></li>
716<li>Release 1.9: <b>RELEASE_19</b></li>
717<li>Release 1.8: <b>RELEASE_18</b></li>
718<li>Release 1.7: <b>RELEASE_17</b></li>
719<li>Release 1.6: <b>RELEASE_16</b></li>
720<li>Release 1.5: <b>RELEASE_15</b></li>
721<li>Release 1.4: <b>RELEASE_14</b></li>
722<li>Release 1.3: <b>RELEASE_13</b></li>
723<li>Release 1.2: <b>RELEASE_12</b></li>
724<li>Release 1.1: <b>RELEASE_11</b></li>
725<li>Release 1.0: <b>RELEASE_1</b></li>
726</ul>
727
728<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
729you get it from the Subversion repository:</p>
730
731<div class="doc_code">
732<pre>
733% cd llvm/projects
734% svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
735</pre>
736</div>
737
738<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
739configured by the LLVM configure script as well as automatically updated when
740you run <tt>svn update</tt>.</p>
741
742<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]743and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]744instructions</a> to successfully get and build the LLVM GCC front-end.</p>
745
746</div>
747
748<!-- ======================================================================= -->
749<div class="doc_subsection">
750 <a name="installcf">Install the GCC Front End</a>
751</div>
752
753<div class="doc_text">
754
755<p>Before configuring and compiling the LLVM suite, you can optionally extract the
756LLVM GCC front end from the binary distribution. It is used for running the
757llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]758<a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]759main LLVM repository.</p>
760
761<p>To install the GCC front end, do the following:</p>
762
763<ol>
764 <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]765 <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]766 -</tt></li>
767</ol>
768
769<p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
770llvm-g++ to some directory in your path. When you configure LLVM, it will
771automatically detect llvm-gcc's presence (if it is in your path) enabling its
772use in llvm-test. Note that you can always build or install llvm-gcc at any
773pointer after building the main LLVM repository: just reconfigure llvm and
774llvm-test will pick it up.
775</p>
776
777<p>The binary versions of the GCC front end may not suit all of your needs. For
778example, the binary distribution may include an old version of a system header
779file, not "fix" a header file that needs to be fixed for GCC, or it may be
780linked with libraries not available on your system.</p>
781
782<p>In cases like these, you may want to try <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]783href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]784much easier now than it was in the past.</p>
785
786</div>
787
788<!-- ======================================================================= -->
789<div class="doc_subsection">
790 <a name="config">Local LLVM Configuration</a>
791</div>
792
793<div class="doc_text">
794
795 <p>Once checked out from the Subversion repository, the LLVM suite source
796 code must be
797configured via the <tt>configure</tt> script. This script sets variables in the
798various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
799<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
800the Makefiles needed to begin building LLVM.</p>
801
802<p>The following environment variables are used by the <tt>configure</tt>
803script to configure the build system:</p>
804
805<table summary="LLVM configure script environment variables">
806 <tr><th>Variable</th><th>Purpose</th></tr>
807 <tr>
808 <td>CC</td>
809 <td>Tells <tt>configure</tt> which C compiler to use. By default,
810 <tt>configure</tt> will look for the first GCC C compiler in
811 <tt>PATH</tt>. Use this variable to override
812 <tt>configure</tt>'s default behavior.</td>
813 </tr>
814 <tr>
815 <td>CXX</td>
816 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
817 <tt>configure</tt> will look for the first GCC C++ compiler in
818 <tt>PATH</tt>. Use this variable to override
819 <tt>configure</tt>'s default behavior.</td>
820 </tr>
821</table>
822
823<p>The following options can be used to set or enable LLVM specific options:</p>
824
825<dl>
826 <dt><i>--with-llvmgccdir</i></dt>
827 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
828 The value of this option should specify the full pathname of the C/C++ Front
829 End to be used. If this option is not provided, the PATH will be searched for
830 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
831 be inferred from the path found. If the option is not given, and no llvm-gcc
832 can be found in the path then a warning will be produced by
833 <tt>configure</tt> indicating this situation. LLVM may still be built with
834 the <tt>tools-only</tt> target but attempting to build the runtime libraries
835 will fail as these libraries require llvm-gcc and llvm-g++. See
836 <a href="#installcf">Install the GCC Front End</a> for details on installing
837 the C/C++ Front End. See
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]838 <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]839 for details on building the C/C++ Front End.</dd>
840 <dt><i>--with-tclinclude</i></dt>
841 <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
842 found. Use this if you have multiple tcl installations on your machine and you
843 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
844 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
845 option, the LLVM configure script will search for the tcl 8.4 and 8.3
846 releases.
847 <br><br>
848 </dd>
849 <dt><i>--enable-optimized</i></dt>
850 <dd>
851 Enables optimized compilation by default (debugging symbols are removed
852 and GCC optimization flags are enabled). The default is to use an
853 unoptimized build (also known as a debug build).
854 <br><br>
855 </dd>
856 <dt><i>--enable-debug-runtime</i></dt>
857 <dd>
858 Enables debug symbols in the runtime libraries. The default is to strip
859 debug symbols from the runtime libraries.
860 </dd>
861 <dt><i>--enable-jit</i></dt>
862 <dd>
863 Compile the Just In Time (JIT) compiler functionality. This is not
864 available
865 on all platforms. The default is dependent on platform, so it is best
866 to explicitly enable it if you want it.
867 <br><br>
868 </dd>
869 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
870 <dd>Controls which targets will be built and linked into llc. The default
871 value for <tt>target_options</tt> is "all" which builds and links all
872 available targets. The value "host-only" can be specified to build only a
873 native compiler (no cross-compiler targets available). The "native" target is
874 selected as the target of the build host. You can also specify a comma
875 separated list of target names that you want available in llc. The target
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]876 names use all lower case. The current set of targets is: <br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]877 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
878 <br><br></dd>
879 <dt><i>--enable-doxygen</i></dt>
880 <dd>Look for the doxygen program and enable construction of doxygen based
881 documentation from the source code. This is disabled by default because
882 generating the documentation can take a long time and producess 100s of
883 megabytes of output.</dd>
884 <dt><i>--with-udis86</i></dt>
885 <dd>LLVM can use external disassembler library for various purposes (now it's
886 used only for examining code produced by JIT). This option will enable usage
887 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
888 bits) disassembler library.</dd>
889</dl>
890
891<p>To configure LLVM, follow these steps:</p>
892
893<ol>
894 <li><p>Change directory into the object root directory:</p>
895
896 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
897
898 <li><p>Run the <tt>configure</tt> script located in the LLVM source
899 tree:</p>
900
901 <div class="doc_code">
902 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
903 </div></li>
904</ol>
905
906</div>
907
908<!-- ======================================================================= -->
909<div class="doc_subsection">
910 <a name="compile">Compiling the LLVM Suite Source Code</a>
911</div>
912
913<div class="doc_text">
914
915<p>Once you have configured LLVM, you can build it. There are three types of
916builds:</p>
917
918<dl>
919 <dt>Debug Builds
920 <dd>
921 These builds are the default when one types <tt>gmake</tt> (unless the
922 <tt>--enable-optimized</tt> option was used during configuration). The
923 build system will compile the tools and libraries with debugging
924 information.
925 <br><br>
926
927 <dt>Release (Optimized) Builds
928 <dd>
929 These builds are enabled with the <tt>--enable-optimized</tt> option to
930 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
931 <tt>gmake</tt> command line. For these builds, the build system will
932 compile the tools and libraries with GCC optimizations enabled and strip
933 debugging information from the libraries and executables it generates.
934 <br><br>
935
936 <dt>Profile Builds
937 <dd>
938 These builds are for use with profiling. They compile profiling
939 information into the code for use with programs like <tt>gprof</tt>.
940 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
941 on the <tt>gmake</tt> command line.
942</dl>
943
944<p>Once you have LLVM configured, you can build it by entering the
945<i>OBJ_ROOT</i> directory and issuing the following command:</p>
946
947<div class="doc_code"><pre>% gmake</pre></div>
948
949<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
950are using a version of GCC that is known not to compile LLVM.</p>
951
952<p>
953If you have multiple processors in your machine, you may wish to use some of
954the parallel build options provided by GNU Make. For example, you could use the
955command:</p>
956
957<div class="doc_code"><pre>% gmake -j2</pre></div>
958
959<p>There are several special targets which are useful when working with the LLVM
960source code:</p>
961
962<dl>
963 <dt><tt>gmake clean</tt>
964 <dd>
965 Removes all files generated by the build. This includes object files,
966 generated C/C++ files, libraries, and executables.
967 <br><br>
968
969 <dt><tt>gmake dist-clean</tt>
970 <dd>
971 Removes everything that <tt>gmake clean</tt> does, but also removes files
972 generated by <tt>configure</tt>. It attempts to return the source tree to the
973 original state in which it was shipped.
974 <br><br>
975
976 <dt><tt>gmake install</tt>
977 <dd>
978 Installs LLVM header files, libraries, tools, and documentation in a
979 hierarchy
980 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
981 defaults to <tt>/usr/local</tt>.
982 <br><br>
983
984 <dt><tt>gmake -C runtime install-bytecode</tt>
985 <dd>
986 Assuming you built LLVM into $OBJDIR, when this command is run, it will
987 install bitcode libraries into the GCC front end's bitcode library
988 directory. If you need to update your bitcode libraries,
989 this is the target to use once you've built them.
990 <br><br>
991</dl>
992
993<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
994details on these <tt>make</tt> targets and descriptions of other targets
995available.</p>
996
997<p>It is also possible to override default values from <tt>configure</tt> by
998declaring variables on the command line. The following are some examples:</p>
999
1000<dl>
1001 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1002 <dd>
1003 Perform a Release (Optimized) build.
1004 <br><br>
1005
1006 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1007 <dd>
1008 Perform a Release (Optimized) build without assertions enabled.
1009 <br><br>
1010
1011 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1012 <dd>
1013 Perform a Profiling build.
1014 <br><br>
1015
1016 <dt><tt>gmake VERBOSE=1</tt>
1017 <dd>
1018 Print what <tt>gmake</tt> is doing on standard output.
1019 <br><br>
1020
1021 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1022 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1023 the standard output. This also implies <tt>VERBOSE=1</tt>.
1024 <br><br></dd>
1025</dl>
1026
1027<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1028it and any subdirectories that it contains. Entering any directory inside the
1029LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1030that directory that is out of date.</p>
1031
1032</div>
1033
1034<!-- ======================================================================= -->
1035<div class="doc_subsection">
1036 <a name="cross-compile">Cross-Compiling LLVM</a>
1037</div>
1038
1039<div class="doc_text">
Jim Grosbachc8c74362009-04-17 17:25:16 +0000[diff] [blame]1040 <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
1041 executables and libraries to be hosted on a platform different from the
1042 platform where they are build (a Canadian Cross build). To configure a
1043 cross-compile, supply the configure script with <tt>--build</tt> and
1044 <tt>--host</tt> options that are different. The values of these options must
1045 be legal target triples that your GCC compiler supports.</p>
1046
1047 <p>The result of such a build is executables that are not runnable on
1048 on the build host (--build option) but can be executed on the compile host
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1049 (--host option).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1050</div>
1051
1052<!-- ======================================================================= -->
1053<div class="doc_subsection">
1054 <a name="objfiles">The Location of LLVM Object Files</a>
1055</div>
1056
1057<div class="doc_text">
1058
1059<p>The LLVM build system is capable of sharing a single LLVM source tree among
1060several LLVM builds. Hence, it is possible to build LLVM for several different
1061platforms or configurations using the same source tree.</p>
1062
1063<p>This is accomplished in the typical autoconf manner:</p>
1064
1065<ul>
1066 <li><p>Change directory to where the LLVM object files should live:</p>
1067
1068 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1069
1070 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1071 directory:</p>
1072
1073 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1074</ul>
1075
1076<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1077named after the build type:</p>
1078
1079<dl>
1080 <dt>Debug Builds
1081 <dd>
1082 <dl>
1083 <dt>Tools
1084 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1085 <dt>Libraries
1086 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1087 </dl>
1088 <br><br>
1089
1090 <dt>Release Builds
1091 <dd>
1092 <dl>
1093 <dt>Tools
1094 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1095 <dt>Libraries
1096 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1097 </dl>
1098 <br><br>
1099
1100 <dt>Profile Builds
1101 <dd>
1102 <dl>
1103 <dt>Tools
1104 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1105 <dt>Libraries
1106 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1107 </dl>
1108</dl>
1109
1110</div>
1111
1112<!-- ======================================================================= -->
1113<div class="doc_subsection">
1114 <a name="optionalconfig">Optional Configuration Items</a>
1115</div>
1116
1117<div class="doc_text">
1118
1119<p>
1120If you're running on a Linux system that supports the "<a
1121href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1122module, and you have root access on the system, you can set your system up to
1123execute LLVM bitcode files directly. To do this, use commands like this (the
1124first command may not be required if you are already using the module):</p>
1125
1126<div class="doc_code">
1127<pre>
1128$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1129$ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1130$ chmod u+x hello.bc (if needed)
1131$ ./hello.bc
1132</pre>
1133</div>
1134
1135<p>
1136This allows you to execute LLVM bitcode files directly. Thanks to Jack
1137Cummings for pointing this out!
1138</p>
1139
1140</div>
1141
1142
1143<!-- *********************************************************************** -->
1144<div class="doc_section">
1145 <a name="layout"><b>Program Layout</b></a>
1146</div>
1147<!-- *********************************************************************** -->
1148
1149<div class="doc_text">
1150
1151<p>One useful source of information about the LLVM source base is the LLVM <a
1152href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1153href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1154The following is a brief introduction to code layout:</p>
1155
1156</div>
1157
1158<!-- ======================================================================= -->
1159<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1160<div class="doc_text">
1161 <p>This directory contains some simple examples of how to use the LLVM IR and
1162 JIT.</p>
1163</div>
1164
1165<!-- ======================================================================= -->
1166<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1167<div class="doc_text">
1168
1169<p>This directory contains public header files exported from the LLVM
1170library. The three main subdirectories of this directory are:</p>
1171
1172<dl>
1173 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1174 <dd>This directory contains all of the LLVM specific header files. This
1175 directory also has subdirectories for different portions of LLVM:
1176 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1177 etc...</dd>
1178
1179 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1180 <dd>This directory contains generic support libraries that are provided with
1181 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1182 and a Command Line option processing library store their header files here.
1183 </dd>
1184
1185 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1186 <dd>This directory contains header files configured by the <tt>configure</tt>
1187 script. They wrap "standard" UNIX and C header files. Source code can
1188 include these header files which automatically take care of the conditional
1189 #includes that the <tt>configure</tt> script generates.</dd>
1190</dl>
1191</div>
1192
1193<!-- ======================================================================= -->
1194<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1195<div class="doc_text">
1196
1197<p>This directory contains most of the source files of the LLVM system. In LLVM,
1198almost all code exists in libraries, making it very easy to share code among the
1199different <a href="#tools">tools</a>.</p>
1200
1201<dl>
1202 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1203 <dd> This directory holds the core LLVM source files that implement core
1204 classes like Instruction and BasicBlock.</dd>
1205
1206 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1207 <dd>This directory holds the source code for the LLVM assembly language parser
1208 library.</dd>
1209
1210 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1211 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1212
1213 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1214 different program analyses, such as Dominator Information, Call Graphs,
1215 Induction Variables, Interval Identification, Natural Loop Identification,
1216 etc.</dd>
1217
1218 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1219 <dd> This directory contains the source code for the LLVM to LLVM program
1220 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1221 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1222 Elimination, and many others.</dd>
1223
1224 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1225 <dd> This directory contains files that describe various target architectures
1226 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1227 directory holds the X86 machine description while
1228 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1229
1230 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1231 <dd> This directory contains the major parts of the code generator: Instruction
1232 Selector, Instruction Scheduling, and Register Allocation.</dd>
1233
1234 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1235 <dd> This directory contains the source level debugger library that makes
1236 it possible to instrument LLVM programs so that a debugger could identify
1237 source code locations at which the program is executing.</dd>
1238
1239 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1240 <dd> This directory contains libraries for executing LLVM bitcode directly
1241 at runtime in both interpreted and JIT compiled fashions.</dd>
1242
1243 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1244 <dd> This directory contains the source code that corresponds to the header
1245 files located in <tt>llvm/include/Support/</tt>.</dd>
1246
1247 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1248 <dd>This directory contains the operating system abstraction layer that
1249 shields LLVM from platform-specific coding.</dd>
1250</dl>
1251
1252</div>
1253
1254<!-- ======================================================================= -->
1255<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1256<div class="doc_text">
1257 <p>This directory contains projects that are not strictly part of LLVM but are
1258 shipped with LLVM. This is also the directory where you should create your own
1259 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
Chris Lattneraf1df782008-08-11 06:13:31 +0000[diff] [blame]1260 to set up your own project.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1261</div>
1262
1263<!-- ======================================================================= -->
1264<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1265<div class="doc_text">
1266
1267<p>This directory contains libraries which are compiled into LLVM bitcode and
1268used when linking programs with the GCC front end. Most of these libraries are
1269skeleton versions of real libraries; for example, libc is a stripped down
1270version of glibc.</p>
1271
1272<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1273end to compile.</p>
1274
1275</div>
1276
1277<!-- ======================================================================= -->
1278<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1279<div class="doc_text">
1280 <p>This directory contains feature and regression tests and other basic sanity
1281 checks on the LLVM infrastructure. These are intended to run quickly and cover
1282 a lot of territory without being exhaustive.</p>
1283</div>
1284
1285<!-- ======================================================================= -->
1286<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1287<div class="doc_text">
1288 <p>This is not a directory in the normal llvm module; it is a separate
1289 Subversion
1290 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1291 This
1292 module contains a comprehensive correctness, performance, and benchmarking
1293 test
1294 suite for LLVM. It is a separate Subversion module because not every LLVM
1295 user is
1296 interested in downloading or building such a comprehensive test suite. For
1297 further details on this test suite, please see the
1298 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1299</div>
1300
1301<!-- ======================================================================= -->
1302<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1303<div class="doc_text">
1304
1305<p>The <b>tools</b> directory contains the executables built out of the
1306libraries above, which form the main part of the user interface. You can
1307always get help for a tool by typing <tt>tool_name --help</tt>. The
1308following is a brief introduction to the most important tools. More detailed
1309information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1310
1311<dl>
1312
1313 <dt><tt><b>bugpoint</b></tt></dt>
1314 <dd><tt>bugpoint</tt> is used to debug
1315 optimization passes or code generation backends by narrowing down the
1316 given test case to the minimum number of passes and/or instructions that
1317 still cause a problem, whether it is a crash or miscompilation. See <a
1318 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1319 on using <tt>bugpoint</tt>.</dd>
1320
1321 <dt><tt><b>llvmc</b></tt></dt>
1322 <dd>The LLVM Compiler Driver. This program can
1323 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1324 pre-processing, translation, optimization, assembly, and linking of programs
1325 all from one command line. <tt>llvmc</tt> also takes care of processing the
1326 dependent libraries found in bitcode. This reduces the need to get the
1327 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1328 note that this tool, while functional, is still experimental and not feature
1329 complete.</dd>
1330
1331 <dt><tt><b>llvm-ar</b></tt></dt>
1332 <dd>The archiver produces an archive containing
1333 the given LLVM bitcode files, optionally with an index for faster
1334 lookup.</dd>
1335
1336 <dt><tt><b>llvm-as</b></tt></dt>
1337 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1338 bitcode.</dd>
1339
1340 <dt><tt><b>llvm-dis</b></tt></dt>
1341 <dd>The disassembler transforms the LLVM bitcode to human readable
1342 LLVM assembly.</dd>
1343
1344 <dt><tt><b>llvm-ld</b></tt></dt>
1345 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1346 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1347 optimizations and allows optimization modules to be loaded and run so that
1348 language specific optimizations can be applied at link time.</dd>
1349
1350 <dt><tt><b>llvm-link</b></tt></dt>
1351 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1352 a single program.</dd>
1353
1354 <dt><tt><b>lli</b></tt></dt>
1355 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +0000[diff] [blame]1356 can directly execute LLVM bitcode (although very slowly...). For architectures
1357 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1358 will function as a Just-In-Time compiler (if the functionality was compiled
1359 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1360
1361 <dt><tt><b>llc</b></tt></dt>
1362 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1363 translates LLVM bitcode to a native code assembly file or to C code (with
1364 the -march=c option).</dd>
1365
1366 <dt><tt><b>llvm-gcc</b></tt></dt>
1367 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1368 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1369 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1370 usual machine code output. It works just like any other GCC compiler,
1371 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1372 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1373 separate Subversion module.</dd>
1374
1375 <dt><tt><b>opt</b></tt></dt>
1376 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1377 transformations (which are specified on the command line), and then outputs
1378 the resultant bitcode. The '<tt>opt --help</tt>' command is a good way to
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]1379 get a list of the program transformations available in LLVM.<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1380 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1381 LLVM bitcode file and print out the results. It is primarily useful for
1382 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1383</dl>
1384</div>
1385
1386<!-- ======================================================================= -->
1387<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1388<div class="doc_text">
1389
1390<p>This directory contains utilities for working with LLVM source code, and some
1391of the utilities are actually required as part of the build process because they
1392are code generators for parts of LLVM infrastructure.</p>
1393
1394<dl>
1395 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1396 that finds differences between code that LLC generates and code that LLI
1397 generates. This is a useful tool if you are debugging one of them,
1398 assuming that the other generates correct output. For the full user
1399 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1400
1401 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1402 syntax-highlighting files which will work with Emacs and XEmacs editors,
1403 providing syntax highlighting support for LLVM assembly files and TableGen
1404 description files. For information on how to use the syntax files, consult
1405 the <tt>README</tt> file in that directory.<br><br>
1406
1407 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1408 and outputs all non-generated source files, which is useful if one wishes
1409 to do a lot of development across directories and does not want to
1410 individually find each file. One way to use it is to run, for example:
1411 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1412 tree.<br><br>
1413
1414 <dt><tt><b>llvmgrep</b></tt></dt>
1415 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1416 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1417 line. This is a very efficient way of searching the source base for a
1418 particular regular expression.</dd>
1419
1420 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1421 files in the current directory and then compiles and links the tool that
1422 is the first argument. For example, assuming you are in the directory
1423 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1424 simply running <tt>makellvm llc</tt> will make a build of the current
1425 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1426 causing a re-linking of LLC.<br><br>
1427
1428 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1429 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1430 cron script to generate nightly status reports of the functionality of
1431 tools, and the results can be seen by following the appropriate link on
1432 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1433
1434 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1435 the tool used to generate register descriptions, instruction set
1436 descriptions, and even assemblers from common TableGen description
1437 files.<br><br>
1438
1439 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1440 syntax-highlighting files which will work with the VIM editor, providing
1441 syntax highlighting support for LLVM assembly files and TableGen
1442 description files. For information on how to use the syntax files, consult
1443 the <tt>README</tt> file in that directory.<br><br>
1444
1445</dl>
1446
1447</div>
1448
1449<!-- ======================================================================= -->
1450<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1451<div class="doc_text">
1452 <p>This directory contains build scripts and project files for use with
1453 Visual C++. This allows developers on Windows to build LLVM without the need
1454 for Cygwin. The contents of this directory should be considered experimental
1455 at this time.
1456 </p>
1457</div>
1458<!-- *********************************************************************** -->
1459<div class="doc_section">
1460 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1461</div>
1462<!-- *********************************************************************** -->
1463
1464<div class="doc_text">
1465<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
Chris Lattnere6099642009-04-10 15:38:51 +0000[diff] [blame]1466so we only include instructions for llvm-gcc4.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1467</p>
1468
1469<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1470from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1471create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1472the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1473<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1474output.</p>
1475</div>
1476
1477<!-- ======================================================================= -->
1478<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1479
1480<div class="doc_text">
1481
1482<ol>
1483 <li><p>First, create a simple C file, name it 'hello.c':</p>
1484
1485<div class="doc_code">
1486<pre>
1487#include &lt;stdio.h&gt;
1488
1489int main() {
1490 printf("hello world\n");
1491 return 0;
1492}
1493</pre></div></li>
1494
1495 <li><p>Next, compile the C file into a native executable:</p>
1496
1497 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1498
1499 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1500 -c arguments work as usual (producing a native .s or .o file,
1501 respectively).</p></li>
1502
1503 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1504
1505 <div class="doc_code">
1506 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1507
1508 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1509 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1510 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1511 the bitcode file.</p>
1512
1513 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1514 </p></li>
1515
1516 <li><p>Run the program in both forms. To run the program, use:</p>
1517
1518 <div class="doc_code"><pre>% ./hello</pre></div>
1519
1520 <p>and</p>
1521
1522 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1523
1524 <p>The second examples shows how to invoke the LLVM JIT, <a
1525 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1526
1527 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1528 code:</p>
1529
1530<div class="doc_code">
1531<pre>llvm-dis &lt; hello.bc | less</pre>
1532</div></li>
1533
1534 <li><p>Compile the program to native assembly using the LLC code
1535 generator:</p>
1536
1537 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1538
1539 <li><p>Assemble the native assembly language file into a program:</p>
1540
1541<div class="doc_code">
1542<pre>
1543<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1544
1545<b>Others:</b> % gcc hello.s -o hello.native
1546</pre>
1547</div></li>
1548
1549 <li><p>Execute the native code program:</p>
1550
1551 <div class="doc_code"><pre>% ./hello.native</pre></div>
1552
1553 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1554 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1555 </li>
1556
1557</ol>
1558
1559</div>
1560
1561
1562<!-- *********************************************************************** -->
1563<div class="doc_section">
1564 <a name="problems">Common Problems</a>
1565</div>
1566<!-- *********************************************************************** -->
1567
1568<div class="doc_text">
1569
1570<p>If you are having problems building or using LLVM, or if you have any other
1571general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1572Asked Questions</a> page.</p>
1573
1574</div>
1575
1576<!-- *********************************************************************** -->
1577<div class="doc_section">
1578 <a name="links">Links</a>
1579</div>
1580<!-- *********************************************************************** -->
1581
1582<div class="doc_text">
1583
Bill Wendling08f49b92008-07-22 01:10:25 +0000[diff] [blame]1584<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]1585some simple things... there are many more interesting and complicated things
1586that you can do that aren't documented here (but we'll gladly accept a patch
1587if you want to write something up!). For more information about LLVM, check
1588out:</p>
1589
1590<ul>
1591 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1592 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1593 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1594 that Uses LLVM</a></li>
1595</ul>
1596
1597</div>
1598
1599<!-- *********************************************************************** -->
1600
1601<hr>
1602<address>
1603 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1607
1608 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1609 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1610 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
1611 Last modified: $Date$
1612</address>
1613</body>
1614</html>