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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
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]690the 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]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>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]711<li>Release 2.5: <b>RELEASE_25</b></li>
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]712<li>Release 2.4: <b>RELEASE_24</b></li>
Tanya Lattner9eb3be52008-06-09 06:02:09 +0000[diff] [blame]713<li>Release 2.3: <b>RELEASE_23</b></li>
Tanya Lattner60030782008-02-12 02:42:55 +0000[diff] [blame]714<li>Release 2.2: <b>RELEASE_22</b></li>
Tanya Lattner2fad5b02007-09-28 22:50:54 +0000[diff] [blame]715<li>Release 2.1: <b>RELEASE_21</b></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]716<li>Release 2.0: <b>RELEASE_20</b></li>
717<li>Release 1.9: <b>RELEASE_19</b></li>
718<li>Release 1.8: <b>RELEASE_18</b></li>
719<li>Release 1.7: <b>RELEASE_17</b></li>
720<li>Release 1.6: <b>RELEASE_16</b></li>
721<li>Release 1.5: <b>RELEASE_15</b></li>
722<li>Release 1.4: <b>RELEASE_14</b></li>
723<li>Release 1.3: <b>RELEASE_13</b></li>
724<li>Release 1.2: <b>RELEASE_12</b></li>
725<li>Release 1.1: <b>RELEASE_11</b></li>
726<li>Release 1.0: <b>RELEASE_1</b></li>
727</ul>
728
729<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
730you get it from the Subversion repository:</p>
731
732<div class="doc_code">
733<pre>
734% cd llvm/projects
735% svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
736</pre>
737</div>
738
739<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
740configured by the LLVM configure script as well as automatically updated when
741you run <tt>svn update</tt>.</p>
742
743<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]744and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]745instructions</a> to successfully get and build the LLVM GCC front-end.</p>
746
747</div>
748
749<!-- ======================================================================= -->
750<div class="doc_subsection">
751 <a name="installcf">Install the GCC Front End</a>
752</div>
753
754<div class="doc_text">
755
756<p>Before configuring and compiling the LLVM suite, you can optionally extract the
757LLVM GCC front end from the binary distribution. It is used for running the
758llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]759<a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]760main LLVM repository.</p>
761
762<p>To install the GCC front end, do the following:</p>
763
764<ol>
765 <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]766 <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]767 -</tt></li>
768</ol>
769
770<p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
771llvm-g++ to some directory in your path. When you configure LLVM, it will
772automatically detect llvm-gcc's presence (if it is in your path) enabling its
773use in llvm-test. Note that you can always build or install llvm-gcc at any
774pointer after building the main LLVM repository: just reconfigure llvm and
775llvm-test will pick it up.
776</p>
777
778<p>The binary versions of the GCC front end may not suit all of your needs. For
779example, the binary distribution may include an old version of a system header
780file, not "fix" a header file that needs to be fixed for GCC, or it may be
781linked with libraries not available on your system.</p>
782
783<p>In cases like these, you may want to try <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]784href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]785much easier now than it was in the past.</p>
786
787</div>
788
789<!-- ======================================================================= -->
790<div class="doc_subsection">
791 <a name="config">Local LLVM Configuration</a>
792</div>
793
794<div class="doc_text">
795
796 <p>Once checked out from the Subversion repository, the LLVM suite source
797 code must be
798configured via the <tt>configure</tt> script. This script sets variables in the
799various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
800<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
801the Makefiles needed to begin building LLVM.</p>
802
803<p>The following environment variables are used by the <tt>configure</tt>
804script to configure the build system:</p>
805
806<table summary="LLVM configure script environment variables">
807 <tr><th>Variable</th><th>Purpose</th></tr>
808 <tr>
809 <td>CC</td>
810 <td>Tells <tt>configure</tt> which C compiler to use. By default,
811 <tt>configure</tt> will look for the first GCC C compiler in
812 <tt>PATH</tt>. Use this variable to override
813 <tt>configure</tt>'s default behavior.</td>
814 </tr>
815 <tr>
816 <td>CXX</td>
817 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
818 <tt>configure</tt> will look for the first GCC C++ compiler in
819 <tt>PATH</tt>. Use this variable to override
820 <tt>configure</tt>'s default behavior.</td>
821 </tr>
822</table>
823
824<p>The following options can be used to set or enable LLVM specific options:</p>
825
826<dl>
827 <dt><i>--with-llvmgccdir</i></dt>
828 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
829 The value of this option should specify the full pathname of the C/C++ Front
830 End to be used. If this option is not provided, the PATH will be searched for
831 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
832 be inferred from the path found. If the option is not given, and no llvm-gcc
833 can be found in the path then a warning will be produced by
834 <tt>configure</tt> indicating this situation. LLVM may still be built with
835 the <tt>tools-only</tt> target but attempting to build the runtime libraries
836 will fail as these libraries require llvm-gcc and llvm-g++. See
837 <a href="#installcf">Install the GCC Front End</a> for details on installing
838 the C/C++ Front End. See
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]839 <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]840 for details on building the C/C++ Front End.</dd>
841 <dt><i>--with-tclinclude</i></dt>
842 <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
843 found. Use this if you have multiple tcl installations on your machine and you
844 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
845 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
846 option, the LLVM configure script will search for the tcl 8.4 and 8.3
847 releases.
848 <br><br>
849 </dd>
850 <dt><i>--enable-optimized</i></dt>
851 <dd>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]852 Enables optimized compilation (debugging symbols are removed
853 and GCC optimization flags are enabled). Note that this is the default
854 setting if you are using the LLVM distribution. The default behavior
855 of an Subversion checkout is to use an unoptimized build (also known as a
856 debug build).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]857 <br><br>
858 </dd>
859 <dt><i>--enable-debug-runtime</i></dt>
860 <dd>
861 Enables debug symbols in the runtime libraries. The default is to strip
862 debug symbols from the runtime libraries.
863 </dd>
864 <dt><i>--enable-jit</i></dt>
865 <dd>
866 Compile the Just In Time (JIT) compiler functionality. This is not
867 available
868 on all platforms. The default is dependent on platform, so it is best
869 to explicitly enable it if you want it.
870 <br><br>
871 </dd>
872 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
873 <dd>Controls which targets will be built and linked into llc. The default
874 value for <tt>target_options</tt> is "all" which builds and links all
875 available targets. The value "host-only" can be specified to build only a
876 native compiler (no cross-compiler targets available). The "native" target is
877 selected as the target of the build host. You can also specify a comma
878 separated list of target names that you want available in llc. The target
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]879 names use all lower case. The current set of targets is: <br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]880 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
881 <br><br></dd>
882 <dt><i>--enable-doxygen</i></dt>
883 <dd>Look for the doxygen program and enable construction of doxygen based
884 documentation from the source code. This is disabled by default because
885 generating the documentation can take a long time and producess 100s of
886 megabytes of output.</dd>
887 <dt><i>--with-udis86</i></dt>
888 <dd>LLVM can use external disassembler library for various purposes (now it's
889 used only for examining code produced by JIT). This option will enable usage
890 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
891 bits) disassembler library.</dd>
892</dl>
893
894<p>To configure LLVM, follow these steps:</p>
895
896<ol>
897 <li><p>Change directory into the object root directory:</p>
898
899 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
900
901 <li><p>Run the <tt>configure</tt> script located in the LLVM source
902 tree:</p>
903
904 <div class="doc_code">
905 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
906 </div></li>
907</ol>
908
909</div>
910
911<!-- ======================================================================= -->
912<div class="doc_subsection">
913 <a name="compile">Compiling the LLVM Suite Source Code</a>
914</div>
915
916<div class="doc_text">
917
918<p>Once you have configured LLVM, you can build it. There are three types of
919builds:</p>
920
921<dl>
922 <dt>Debug Builds
923 <dd>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]924 These builds are the default when one is using an Subversion checkout and
925 types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was
926 used during configuration). The build system will compile the tools and
927 libraries with debugging information. To get a Debug Build using the
928 LLVM distribution the <tt>--disable-optimized</tt> option must be passed
929 to <tt>configure</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]930 <br><br>
931
932 <dt>Release (Optimized) Builds
933 <dd>
934 These builds are enabled with the <tt>--enable-optimized</tt> option to
935 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
936 <tt>gmake</tt> command line. For these builds, the build system will
937 compile the tools and libraries with GCC optimizations enabled and strip
938 debugging information from the libraries and executables it generates.
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]939 Note that Release Builds are default when using an LLVM distribution.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]940 <br><br>
941
942 <dt>Profile Builds
943 <dd>
944 These builds are for use with profiling. They compile profiling
945 information into the code for use with programs like <tt>gprof</tt>.
946 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
947 on the <tt>gmake</tt> command line.
948</dl>
949
950<p>Once you have LLVM configured, you can build it by entering the
951<i>OBJ_ROOT</i> directory and issuing the following command:</p>
952
953<div class="doc_code"><pre>% gmake</pre></div>
954
955<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
956are using a version of GCC that is known not to compile LLVM.</p>
957
958<p>
959If you have multiple processors in your machine, you may wish to use some of
960the parallel build options provided by GNU Make. For example, you could use the
961command:</p>
962
963<div class="doc_code"><pre>% gmake -j2</pre></div>
964
965<p>There are several special targets which are useful when working with the LLVM
966source code:</p>
967
968<dl>
969 <dt><tt>gmake clean</tt>
970 <dd>
971 Removes all files generated by the build. This includes object files,
972 generated C/C++ files, libraries, and executables.
973 <br><br>
974
975 <dt><tt>gmake dist-clean</tt>
976 <dd>
977 Removes everything that <tt>gmake clean</tt> does, but also removes files
978 generated by <tt>configure</tt>. It attempts to return the source tree to the
979 original state in which it was shipped.
980 <br><br>
981
982 <dt><tt>gmake install</tt>
983 <dd>
984 Installs LLVM header files, libraries, tools, and documentation in a
985 hierarchy
986 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
987 defaults to <tt>/usr/local</tt>.
988 <br><br>
989
990 <dt><tt>gmake -C runtime install-bytecode</tt>
991 <dd>
992 Assuming you built LLVM into $OBJDIR, when this command is run, it will
993 install bitcode libraries into the GCC front end's bitcode library
994 directory. If you need to update your bitcode libraries,
995 this is the target to use once you've built them.
996 <br><br>
997</dl>
998
999<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
1000details on these <tt>make</tt> targets and descriptions of other targets
1001available.</p>
1002
1003<p>It is also possible to override default values from <tt>configure</tt> by
1004declaring variables on the command line. The following are some examples:</p>
1005
1006<dl>
1007 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1008 <dd>
1009 Perform a Release (Optimized) build.
1010 <br><br>
1011
1012 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1013 <dd>
1014 Perform a Release (Optimized) build without assertions enabled.
1015 <br><br>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000[diff] [blame]1016
1017 <dt><tt>gmake ENABLE_OPTIMIZED=0</tt>
1018 <dd>
1019 Perform a Debug build.
1020 <br><br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1021
1022 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1023 <dd>
1024 Perform a Profiling build.
1025 <br><br>
1026
1027 <dt><tt>gmake VERBOSE=1</tt>
1028 <dd>
1029 Print what <tt>gmake</tt> is doing on standard output.
1030 <br><br>
1031
1032 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1033 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1034 the standard output. This also implies <tt>VERBOSE=1</tt>.
1035 <br><br></dd>
1036</dl>
1037
1038<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1039it and any subdirectories that it contains. Entering any directory inside the
1040LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1041that directory that is out of date.</p>
1042
1043</div>
1044
1045<!-- ======================================================================= -->
1046<div class="doc_subsection">
1047 <a name="cross-compile">Cross-Compiling LLVM</a>
1048</div>
1049
1050<div class="doc_text">
Jim Grosbachc8c74362009-04-17 17:25:16 +0000[diff] [blame]1051 <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
1052 executables and libraries to be hosted on a platform different from the
1053 platform where they are build (a Canadian Cross build). To configure a
1054 cross-compile, supply the configure script with <tt>--build</tt> and
1055 <tt>--host</tt> options that are different. The values of these options must
1056 be legal target triples that your GCC compiler supports.</p>
1057
1058 <p>The result of such a build is executables that are not runnable on
1059 on the build host (--build option) but can be executed on the compile host
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1060 (--host option).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1061</div>
1062
1063<!-- ======================================================================= -->
1064<div class="doc_subsection">
1065 <a name="objfiles">The Location of LLVM Object Files</a>
1066</div>
1067
1068<div class="doc_text">
1069
1070<p>The LLVM build system is capable of sharing a single LLVM source tree among
1071several LLVM builds. Hence, it is possible to build LLVM for several different
1072platforms or configurations using the same source tree.</p>
1073
1074<p>This is accomplished in the typical autoconf manner:</p>
1075
1076<ul>
1077 <li><p>Change directory to where the LLVM object files should live:</p>
1078
1079 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1080
1081 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1082 directory:</p>
1083
1084 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1085</ul>
1086
1087<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1088named after the build type:</p>
1089
1090<dl>
1091 <dt>Debug Builds
1092 <dd>
1093 <dl>
1094 <dt>Tools
1095 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1096 <dt>Libraries
1097 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1098 </dl>
1099 <br><br>
1100
1101 <dt>Release Builds
1102 <dd>
1103 <dl>
1104 <dt>Tools
1105 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1106 <dt>Libraries
1107 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1108 </dl>
1109 <br><br>
1110
1111 <dt>Profile Builds
1112 <dd>
1113 <dl>
1114 <dt>Tools
1115 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1116 <dt>Libraries
1117 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1118 </dl>
1119</dl>
1120
1121</div>
1122
1123<!-- ======================================================================= -->
1124<div class="doc_subsection">
1125 <a name="optionalconfig">Optional Configuration Items</a>
1126</div>
1127
1128<div class="doc_text">
1129
1130<p>
1131If you're running on a Linux system that supports the "<a
1132href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1133module, and you have root access on the system, you can set your system up to
1134execute LLVM bitcode files directly. To do this, use commands like this (the
1135first command may not be required if you are already using the module):</p>
1136
1137<div class="doc_code">
1138<pre>
1139$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1140$ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1141$ chmod u+x hello.bc (if needed)
1142$ ./hello.bc
1143</pre>
1144</div>
1145
1146<p>
1147This allows you to execute LLVM bitcode files directly. Thanks to Jack
1148Cummings for pointing this out!
1149</p>
1150
1151</div>
1152
1153
1154<!-- *********************************************************************** -->
1155<div class="doc_section">
1156 <a name="layout"><b>Program Layout</b></a>
1157</div>
1158<!-- *********************************************************************** -->
1159
1160<div class="doc_text">
1161
1162<p>One useful source of information about the LLVM source base is the LLVM <a
1163href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1164href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1165The following is a brief introduction to code layout:</p>
1166
1167</div>
1168
1169<!-- ======================================================================= -->
1170<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1171<div class="doc_text">
1172 <p>This directory contains some simple examples of how to use the LLVM IR and
1173 JIT.</p>
1174</div>
1175
1176<!-- ======================================================================= -->
1177<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1178<div class="doc_text">
1179
1180<p>This directory contains public header files exported from the LLVM
1181library. The three main subdirectories of this directory are:</p>
1182
1183<dl>
1184 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1185 <dd>This directory contains all of the LLVM specific header files. This
1186 directory also has subdirectories for different portions of LLVM:
1187 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1188 etc...</dd>
1189
1190 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1191 <dd>This directory contains generic support libraries that are provided with
1192 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1193 and a Command Line option processing library store their header files here.
1194 </dd>
1195
1196 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1197 <dd>This directory contains header files configured by the <tt>configure</tt>
1198 script. They wrap "standard" UNIX and C header files. Source code can
1199 include these header files which automatically take care of the conditional
1200 #includes that the <tt>configure</tt> script generates.</dd>
1201</dl>
1202</div>
1203
1204<!-- ======================================================================= -->
1205<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1206<div class="doc_text">
1207
1208<p>This directory contains most of the source files of the LLVM system. In LLVM,
1209almost all code exists in libraries, making it very easy to share code among the
1210different <a href="#tools">tools</a>.</p>
1211
1212<dl>
1213 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1214 <dd> This directory holds the core LLVM source files that implement core
1215 classes like Instruction and BasicBlock.</dd>
1216
1217 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1218 <dd>This directory holds the source code for the LLVM assembly language parser
1219 library.</dd>
1220
1221 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1222 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1223
1224 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1225 different program analyses, such as Dominator Information, Call Graphs,
1226 Induction Variables, Interval Identification, Natural Loop Identification,
1227 etc.</dd>
1228
1229 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1230 <dd> This directory contains the source code for the LLVM to LLVM program
1231 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1232 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1233 Elimination, and many others.</dd>
1234
1235 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1236 <dd> This directory contains files that describe various target architectures
1237 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1238 directory holds the X86 machine description while
1239 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1240
1241 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1242 <dd> This directory contains the major parts of the code generator: Instruction
1243 Selector, Instruction Scheduling, and Register Allocation.</dd>
1244
1245 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1246 <dd> This directory contains the source level debugger library that makes
1247 it possible to instrument LLVM programs so that a debugger could identify
1248 source code locations at which the program is executing.</dd>
1249
1250 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1251 <dd> This directory contains libraries for executing LLVM bitcode directly
1252 at runtime in both interpreted and JIT compiled fashions.</dd>
1253
1254 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1255 <dd> This directory contains the source code that corresponds to the header
1256 files located in <tt>llvm/include/Support/</tt>.</dd>
1257
1258 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1259 <dd>This directory contains the operating system abstraction layer that
1260 shields LLVM from platform-specific coding.</dd>
1261</dl>
1262
1263</div>
1264
1265<!-- ======================================================================= -->
1266<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1267<div class="doc_text">
1268 <p>This directory contains projects that are not strictly part of LLVM but are
1269 shipped with LLVM. This is also the directory where you should create your own
1270 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
Chris Lattneraf1df782008-08-11 06:13:31 +0000[diff] [blame]1271 to set up your own project.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1272</div>
1273
1274<!-- ======================================================================= -->
1275<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1276<div class="doc_text">
1277
1278<p>This directory contains libraries which are compiled into LLVM bitcode and
1279used when linking programs with the GCC front end. Most of these libraries are
1280skeleton versions of real libraries; for example, libc is a stripped down
1281version of glibc.</p>
1282
1283<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1284end to compile.</p>
1285
1286</div>
1287
1288<!-- ======================================================================= -->
1289<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1290<div class="doc_text">
1291 <p>This directory contains feature and regression tests and other basic sanity
1292 checks on the LLVM infrastructure. These are intended to run quickly and cover
1293 a lot of territory without being exhaustive.</p>
1294</div>
1295
1296<!-- ======================================================================= -->
1297<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1298<div class="doc_text">
1299 <p>This is not a directory in the normal llvm module; it is a separate
1300 Subversion
1301 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1302 This
1303 module contains a comprehensive correctness, performance, and benchmarking
1304 test
1305 suite for LLVM. It is a separate Subversion module because not every LLVM
1306 user is
1307 interested in downloading or building such a comprehensive test suite. For
1308 further details on this test suite, please see the
1309 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1310</div>
1311
1312<!-- ======================================================================= -->
1313<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1314<div class="doc_text">
1315
1316<p>The <b>tools</b> directory contains the executables built out of the
1317libraries above, which form the main part of the user interface. You can
1318always get help for a tool by typing <tt>tool_name --help</tt>. The
1319following is a brief introduction to the most important tools. More detailed
1320information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1321
1322<dl>
1323
1324 <dt><tt><b>bugpoint</b></tt></dt>
1325 <dd><tt>bugpoint</tt> is used to debug
1326 optimization passes or code generation backends by narrowing down the
1327 given test case to the minimum number of passes and/or instructions that
1328 still cause a problem, whether it is a crash or miscompilation. See <a
1329 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1330 on using <tt>bugpoint</tt>.</dd>
1331
1332 <dt><tt><b>llvmc</b></tt></dt>
1333 <dd>The LLVM Compiler Driver. This program can
1334 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1335 pre-processing, translation, optimization, assembly, and linking of programs
1336 all from one command line. <tt>llvmc</tt> also takes care of processing the
1337 dependent libraries found in bitcode. This reduces the need to get the
1338 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1339 note that this tool, while functional, is still experimental and not feature
1340 complete.</dd>
1341
1342 <dt><tt><b>llvm-ar</b></tt></dt>
1343 <dd>The archiver produces an archive containing
1344 the given LLVM bitcode files, optionally with an index for faster
1345 lookup.</dd>
1346
1347 <dt><tt><b>llvm-as</b></tt></dt>
1348 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1349 bitcode.</dd>
1350
1351 <dt><tt><b>llvm-dis</b></tt></dt>
1352 <dd>The disassembler transforms the LLVM bitcode to human readable
1353 LLVM assembly.</dd>
1354
1355 <dt><tt><b>llvm-ld</b></tt></dt>
1356 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1357 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1358 optimizations and allows optimization modules to be loaded and run so that
1359 language specific optimizations can be applied at link time.</dd>
1360
1361 <dt><tt><b>llvm-link</b></tt></dt>
1362 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1363 a single program.</dd>
1364
1365 <dt><tt><b>lli</b></tt></dt>
1366 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +0000[diff] [blame]1367 can directly execute LLVM bitcode (although very slowly...). For architectures
1368 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1369 will function as a Just-In-Time compiler (if the functionality was compiled
1370 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1371
1372 <dt><tt><b>llc</b></tt></dt>
1373 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1374 translates LLVM bitcode to a native code assembly file or to C code (with
1375 the -march=c option).</dd>
1376
1377 <dt><tt><b>llvm-gcc</b></tt></dt>
1378 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1379 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1380 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1381 usual machine code output. It works just like any other GCC compiler,
1382 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1383 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1384 separate Subversion module.</dd>
1385
1386 <dt><tt><b>opt</b></tt></dt>
1387 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1388 transformations (which are specified on the command line), and then outputs
1389 the resultant bitcode. The '<tt>opt --help</tt>' command is a good way to
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]1390 get a list of the program transformations available in LLVM.<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1391 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1392 LLVM bitcode file and print out the results. It is primarily useful for
1393 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1394</dl>
1395</div>
1396
1397<!-- ======================================================================= -->
1398<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1399<div class="doc_text">
1400
1401<p>This directory contains utilities for working with LLVM source code, and some
1402of the utilities are actually required as part of the build process because they
1403are code generators for parts of LLVM infrastructure.</p>
1404
1405<dl>
1406 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1407 that finds differences between code that LLC generates and code that LLI
1408 generates. This is a useful tool if you are debugging one of them,
1409 assuming that the other generates correct output. For the full user
1410 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1411
1412 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1413 syntax-highlighting files which will work with Emacs and XEmacs editors,
1414 providing syntax highlighting support for LLVM assembly files and TableGen
1415 description files. For information on how to use the syntax files, consult
1416 the <tt>README</tt> file in that directory.<br><br>
1417
1418 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1419 and outputs all non-generated source files, which is useful if one wishes
1420 to do a lot of development across directories and does not want to
1421 individually find each file. One way to use it is to run, for example:
1422 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1423 tree.<br><br>
1424
1425 <dt><tt><b>llvmgrep</b></tt></dt>
1426 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1427 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1428 line. This is a very efficient way of searching the source base for a
1429 particular regular expression.</dd>
1430
1431 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1432 files in the current directory and then compiles and links the tool that
1433 is the first argument. For example, assuming you are in the directory
1434 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1435 simply running <tt>makellvm llc</tt> will make a build of the current
1436 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1437 causing a re-linking of LLC.<br><br>
1438
1439 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1440 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1441 cron script to generate nightly status reports of the functionality of
1442 tools, and the results can be seen by following the appropriate link on
1443 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1444
1445 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1446 the tool used to generate register descriptions, instruction set
1447 descriptions, and even assemblers from common TableGen description
1448 files.<br><br>
1449
1450 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1451 syntax-highlighting files which will work with the VIM editor, providing
1452 syntax highlighting support for LLVM assembly files and TableGen
1453 description files. For information on how to use the syntax files, consult
1454 the <tt>README</tt> file in that directory.<br><br>
1455
1456</dl>
1457
1458</div>
1459
1460<!-- ======================================================================= -->
1461<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1462<div class="doc_text">
1463 <p>This directory contains build scripts and project files for use with
1464 Visual C++. This allows developers on Windows to build LLVM without the need
1465 for Cygwin. The contents of this directory should be considered experimental
1466 at this time.
1467 </p>
1468</div>
1469<!-- *********************************************************************** -->
1470<div class="doc_section">
1471 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1472</div>
1473<!-- *********************************************************************** -->
1474
1475<div class="doc_text">
1476<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
Chris Lattnere6099642009-04-10 15:38:51 +0000[diff] [blame]1477so we only include instructions for llvm-gcc4.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1478</p>
1479
1480<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1481from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1482create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1483the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1484<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1485output.</p>
1486</div>
1487
1488<!-- ======================================================================= -->
1489<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1490
1491<div class="doc_text">
1492
1493<ol>
1494 <li><p>First, create a simple C file, name it 'hello.c':</p>
1495
1496<div class="doc_code">
1497<pre>
1498#include &lt;stdio.h&gt;
1499
1500int main() {
1501 printf("hello world\n");
1502 return 0;
1503}
1504</pre></div></li>
1505
1506 <li><p>Next, compile the C file into a native executable:</p>
1507
1508 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1509
1510 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1511 -c arguments work as usual (producing a native .s or .o file,
1512 respectively).</p></li>
1513
1514 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1515
1516 <div class="doc_code">
1517 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1518
1519 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1520 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1521 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1522 the bitcode file.</p>
1523
1524 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1525 </p></li>
1526
1527 <li><p>Run the program in both forms. To run the program, use:</p>
1528
1529 <div class="doc_code"><pre>% ./hello</pre></div>
1530
1531 <p>and</p>
1532
1533 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1534
1535 <p>The second examples shows how to invoke the LLVM JIT, <a
1536 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1537
1538 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1539 code:</p>
1540
1541<div class="doc_code">
1542<pre>llvm-dis &lt; hello.bc | less</pre>
1543</div></li>
1544
1545 <li><p>Compile the program to native assembly using the LLC code
1546 generator:</p>
1547
1548 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1549
1550 <li><p>Assemble the native assembly language file into a program:</p>
1551
1552<div class="doc_code">
1553<pre>
1554<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1555
1556<b>Others:</b> % gcc hello.s -o hello.native
1557</pre>
1558</div></li>
1559
1560 <li><p>Execute the native code program:</p>
1561
1562 <div class="doc_code"><pre>% ./hello.native</pre></div>
1563
1564 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1565 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1566 </li>
1567
1568</ol>
1569
1570</div>
1571
1572
1573<!-- *********************************************************************** -->
1574<div class="doc_section">
1575 <a name="problems">Common Problems</a>
1576</div>
1577<!-- *********************************************************************** -->
1578
1579<div class="doc_text">
1580
1581<p>If you are having problems building or using LLVM, or if you have any other
1582general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1583Asked Questions</a> page.</p>
1584
1585</div>
1586
1587<!-- *********************************************************************** -->
1588<div class="doc_section">
1589 <a name="links">Links</a>
1590</div>
1591<!-- *********************************************************************** -->
1592
1593<div class="doc_text">
1594
Bill Wendling08f49b92008-07-22 01:10:25 +0000[diff] [blame]1595<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]1596some simple things... there are many more interesting and complicated things
1597that you can do that aren't documented here (but we'll gladly accept a patch
1598if you want to write something up!). For more information about LLVM, check
1599out:</p>
1600
1601<ul>
1602 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1603 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1604 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1605 that Uses LLVM</a></li>
1606</ul>
1607
1608</div>
1609
1610<!-- *********************************************************************** -->
1611
1612<hr>
1613<address>
1614 <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]1618
1619 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1620 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1621 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
1622 Last modified: $Date$
1623</address>
1624</body>
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