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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>
Tanya Lattnerf3ff76b2008-04-07 18:32:25 +0000[diff] [blame]117 <li>Install the llvm-gcc4.2 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>
120 <li><tt>gunzip --stdout llvm-gcc.<i>platform</i>.tar.gz | tar -xvf -</tt>
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
162 not specified, the PATH will be searched.</p></li>
163 <li><tt>--enable-spec2000=<i>directory</i></tt>
164 <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
165 benchmarks should be available in
166 <tt><i>directory</i></tt>.</p></li>
167 </ul>
168 </ol></li>
169
170 <li>Build the LLVM Suite:
171 <ol>
172 <li><tt>gmake -k |&amp; tee gnumake.out
173 &nbsp;&nbsp;&nbsp;# this is csh or tcsh syntax</tt></li>
174 <li>If you get an "internal compiler error (ICE)" or test failures, see
175 <a href="#brokengcc">below</a>.</li>
176 </ol>
177
178</ol>
179
180<p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
181detailed information on configuring and compiling LLVM. See <a
182href="#environment">Setting Up Your Environment</a> for tips that simplify
183working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
184Layout</a> to learn about the layout of the source code tree.</p>
185
186</div>
187
188<!-- *********************************************************************** -->
189<div class="doc_section">
190 <a name="requirements"><b>Requirements</b></a>
191</div>
192<!-- *********************************************************************** -->
193
194<div class="doc_text">
195
196<p>Before you begin to use the LLVM system, review the requirements given below.
197This may save you some trouble by knowing ahead of time what hardware and
198software you will need.</p>
199
200</div>
201
202<!-- ======================================================================= -->
203<div class="doc_subsection">
204 <a name="hardware"><b>Hardware</b></a>
205</div>
206
207<div class="doc_text">
208
209<p>LLVM is known to work on the following platforms:</p>
210
211<table cellpadding="3" summary="Known LLVM platforms">
212<tr>
213 <th>OS</th>
214 <th>Arch</th>
215 <th>Compilers</th>
216</tr>
217<tr>
218 <td>Linux</td>
219 <td>x86<sup><a href="#pf_1">1</a></sup></td>
220 <td>GCC</td>
221</tr>
222<tr>
223 <td>Solaris</td>
224 <td>V9 (Ultrasparc)</td>
225 <td>GCC</td>
226</tr>
227<tr>
228 <td>FreeBSD</td>
229 <td>x86<sup><a href="#pf_1">1</a></sup></td>
230 <td>GCC</td>
231</tr>
232<tr>
233 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
234 <td>PowerPC</td>
235 <td>GCC</td>
236</tr>
237<tr>
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]238 <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]239 <td>x86</td>
240 <td>GCC</td>
241
242</tr>
243<tr>
244 <td>Cygwin/Win32</td>
245 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a></sup></td>
246 <td>GCC 3.4.X, binutils 2.15</td>
247</tr>
248<tr>
249 <td>MinGW/Win32</td>
250 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,<a href="#pf_8">8</a></sup></td>
251 <td>GCC 3.4.X, binutils 2.15</td>
252</tr>
253<tr>
254 <td>Linux</td>
Dan Gohman99fc2442008-11-13 19:07:07 +0000[diff] [blame]255 <td>amd64</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]256 <td>GCC</td>
257</tr>
258</table>
259
260<p>LLVM has partial support for the following platforms:</p>
261
262<table summary="LLVM partial platform support">
263<tr>
264 <th>OS</th>
265 <th>Arch</th>
266 <th>Compilers</th>
267</tr>
268<tr>
269 <td>Windows</td>
270 <td>x86<sup><a href="#pf_1">1</a></sup></td>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]271 <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]272<tr>
273 <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
274 <td>PowerPC</td>
275 <td>GCC</td>
276</tr>
277<tr>
278 <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
279 <td>PowerPC</td>
280 <td>GCC</td>
281</tr>
282
283<tr>
284 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
285 <td>Alpha</td>
286 <td>GCC</td>
287</tr>
288<tr>
289 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
290 <td>Itanium (IA-64)</td>
291 <td>GCC</td>
292</tr>
293<tr>
294 <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
295 <td>Itanium (IA-64)</td>
296 <td>HP aCC</td>
297</tr>
298</table>
299
300<p><b>Notes:</b></p>
301
302<div class="doc_notes">
303<ol>
304<li><a name="pf_1">Code generation supported for Pentium processors and
305up</a></li>
306<li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
307<li><a name="pf_3">No native code generation</a></li>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]308<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]309<li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
310<li><a name="pf_6">The port is done using the MSYS shell.</a>
311<a href="http://www.mingw.org/MinGWiki/">Download</a> and install
312bison (excl. M4.exe) and flex in that order. Build binutils-2.15 from source,
313if necessary. Bison &amp; flex can be also grabbed from GNUWin32 sf.net
314project.</li>
315<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
316<li><a name="pf_8">Binutils</a> up to post-2.17 has bug in bfd/cofflink.c
317 preventing LLVM from building correctly. Several workarounds have been
318 introduced into LLVM build system, but the bug can occur anytime in the
319 future. We highly recommend that you rebuild your current binutils with the
320 patch from <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=2659">
321 Binutils bugzilla</a>, if it wasn't already applied.</li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]322<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]323 internal LLVM assert messages when compiled for Release at optimization
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]324 levels greater than 0 (i.e., <i>"-O1"</i> and higher).
325 Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]326 if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]327</ol>
328</div>
329
330<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
331mode, depending on the system (it is so large because of all the debugging
332information and the fact that the libraries are statically linked into multiple
333tools). If you do not need many of the tools and you are space-conscious,
334you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
335build requires considerably less space.</p>
336
337<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
338guaranteed to do so. If compilation is successful, the LLVM utilities should be
339able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
340generation should work as well, although the generated native code may not work
341on your platform.</p>
342
343<p>The GCC front end is not very portable at the moment. If you want to get it
344to work on another platform, you can download a copy of the source and <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]345href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346
347</div>
348
349<!-- ======================================================================= -->
350<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
351<div class="doc_text">
352 <p>Compiling LLVM requires that you have several software packages
353 installed. The table below lists those required packages. The Package column
354 is the usual name for the software package that LLVM depends on. The Version
355 column provides "known to work" versions of the package. The Notes column
356 describes how LLVM uses the package and provides other details.</p>
357 <table summary="Packages required to compile LLVM">
358 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
359
360 <tr>
361 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
362 <td>3.79, 3.79.1</td>
363 <td>Makefile/build processor</td>
364 </tr>
365
366 <tr>
367 <td><a href="http://gcc.gnu.org">GCC</a></td>
368 <td>3.4.2</td>
369 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
370 </tr>
371
372 <tr>
373 <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
374 <td>4.5</td>
375 <td>For building the CFE</td>
376 </tr>
377
378 <tr>
379 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
380 <td>2.5.4</td>
381 <td>LEX compiler</td>
382 </tr>
383
384 <tr>
385 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
386 <td>1.28, 1.35, 1.75, 1.875d, 2.0, or 2.1<br>(not 1.85 or 1.875)</td>
387 <td>YACC compiler</td>
388 </tr>
389
390 <tr>
391 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
392 <td>&ge;1.3</td>
393 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
394 </tr>
395
396 <tr>
397 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
398 <td>1.4.2</td>
399 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
400 </tr>
401
402 <tr>
403 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
404 <td>8.3, 8.4</td>
405 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
406 </tr>
407
408 <tr>
409 <td><a href="http://expect.nist.gov/">expect</a></td>
410 <td>5.38.0</td>
411 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
412 </tr>
413
414 <tr>
415 <td><a href="http://www.perl.com/download.csp">perl</a></td>
416 <td>&ge;5.6.0</td>
417 <td>Nightly tester, utilities</td>
418 </tr>
419
420 <tr>
421 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
422 <td>1.4</td>
423 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
424 </tr>
425
426 <tr>
427 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
428 <td>2.59</td>
429 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
430 </tr>
431
432 <tr>
433 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
434 <td>1.9.2</td>
435 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
436 </tr>
437
438 <tr>
439 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
440 <td>1.5.10</td>
441 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
442 </tr>
443
444 </table>
445
446 <p><b>Notes:</b></p>
447 <div class="doc_notes">
448 <ol>
449 <li><a name="sf1">Only the C and C++ languages are needed so there's no
450 need to build the other languages for LLVM's purposes.</a> See
451 <a href="#brokengcc">below</a> for specific version info.</li>
452 <li><a name="sf2">You only need Subversion if you intend to build from the
453 latest LLVM sources. If you're working from a release distribution, you
454 don't need Subversion.</a></li>
455 <li><a name="sf3">Only needed if you want to run the automated test
456 suite in the <tt>llvm/test</tt> directory.</a></li>
457 <li><a name="sf4">If you want to make changes to the configure scripts,
458 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
459 or higher). You will also need automake (1.9.2). We only use aclocal
460 from that package.</a></li>
461 </ol>
462 </div>
463
464 <p>Additionally, your compilation host is expected to have the usual
465 plethora of Unix utilities. Specifically:</p>
466 <ul>
467 <li><b>ar</b> - archive library builder</li>
468 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
469 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
470 <li><b>chmod</b> - change permissions on a file</li>
471 <li><b>cat</b> - output concatenation utility</li>
472 <li><b>cp</b> - copy files</li>
473 <li><b>date</b> - print the current date/time </li>
474 <li><b>echo</b> - print to standard output</li>
475 <li><b>egrep</b> - extended regular expression search utility</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]476 <li><b>find</b> - find files/dirs in a file system</li>
477 <li><b>grep</b> - regular expression search utility</li>
478 <li><b>gzip*</b> - gzip command for distribution generation</li>
479 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
480 <li><b>install</b> - install directories/files </li>
481 <li><b>mkdir</b> - create a directory</li>
482 <li><b>mv</b> - move (rename) files</li>
483 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
484 <li><b>rm</b> - remove (delete) files and directories</li>
485 <li><b>sed</b> - stream editor for transforming output</li>
486 <li><b>sh</b> - Bourne shell for make build scripts</li>
487 <li><b>tar</b> - tape archive for distribution generation</li>
488 <li><b>test</b> - test things in file system</li>
489 <li><b>unzip*</b> - unzip command for distribution checking</li>
490 <li><b>zip*</b> - zip command for distribution generation</li>
491 </ul>
492</div>
493
494<!-- ======================================================================= -->
495<div class="doc_subsection">
496 <a name="brokengcc">Broken versions of GCC and other tools</a>
497</div>
498
499<div class="doc_text">
500
501<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
502bugs in the compiler. In particular, several versions of GCC crash when trying
503to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
504successfully with them (however, see important notes below). Other versions
505of GCC will probably work as well. GCC versions listed
506here are known to not work. If you are using one of these versions, please try
507to upgrade your GCC to something more recent. If you run into a problem with a
508version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
509us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
510of GCC you are using.
511</p>
512
513<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
514problems in the STL that effectively prevent it from compiling LLVM.
515</p>
516
Chris Lattner76bb5302008-02-13 17:50:24 +0000[diff] [blame]517<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
518a bogus template error. This was fixed in later GCCs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]519
520<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
521href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
522the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
523
524<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]525 Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]526 to a newer version</a> if possible.</p>
527<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
528 possibly others) does not compile LLVM correctly (it appears that exception
529 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
530 to a newer version of GCC.</p>
531<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
532 code generator, causing an infinite loop in the llvm-gcc build when built
533 with optimizations enabled (i.e. a release build).</p>
534<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
535 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
536 correctly compiles LLVM at -O2. A work around is to build release LLVM
537 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
538<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
539 miscompiles portions of LLVM</a>.</p>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]540<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
541 when building with optimizations enabled. It appears to work with
542 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
543 build.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]544<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
545 miscompile LLVM.</p>
546<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
547 default with ENABLE_OPTIMIZED=1. To work around this, build with
548 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
549<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
550 compiling some files. At the time of this writing, GCC mainline (4.2)
551 did not share the problem.</p>
552<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
553 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
554 code. LLVM will appear to mostly work but will be buggy, e.g. failing
555 portions of its testsuite.</p>
556<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
557platforms compiling md5.c gets a mangled constant.</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000[diff] [blame]558<p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
559to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
560about symbols remaining in the table on destruction.</p>
Nuno Lopesc36ac042008-12-10 16:01:22 +0000[diff] [blame^]561<p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptons
562as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000[diff] [blame]563
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
565long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
566defined in a discarded section. You can safely ignore these messages as they are
567erroneous and the linkage is correct. These messages disappear using ld
5682.17.</p>
569
570<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
571href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
572causes huge link times (minutes instead of seconds) when building LLVM. We
573recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
574
575</div>
576
577
578
579<!-- *********************************************************************** -->
580<div class="doc_section">
581 <a name="starting"><b>Getting Started with LLVM</b></a>
582</div>
583<!-- *********************************************************************** -->
584
585<div class="doc_text">
586
587<p>The remainder of this guide is meant to get you up and running with
588LLVM and to give you some basic information about the LLVM environment.</p>
589
590<p>The later sections of this guide describe the <a
591href="#layout">general layout</a> of the the LLVM source tree, a <a
592href="#tutorial">simple example</a> using the LLVM tool chain, and <a
593href="#links">links</a> to find more information about LLVM or to get
594help via e-mail.</p>
595</div>
596
597<!-- ======================================================================= -->
598<div class="doc_subsection">
599 <a name="terminology">Terminology and Notation</a>
600</div>
601
602<div class="doc_text">
603
604<p>Throughout this manual, the following names are used to denote paths
605specific to the local system and working environment. <i>These are not
606environment variables you need to set but just strings used in the rest
607of this document below</i>. In any of the examples below, simply replace
608each of these names with the appropriate pathname on your local system.
609All these paths are absolute:</p>
610
611<dl>
612 <dt>SRC_ROOT
613 <dd>
614 This is the top level directory of the LLVM source tree.
615 <br><br>
616
617 <dt>OBJ_ROOT
618 <dd>
619 This is the top level directory of the LLVM object tree (i.e. the
620 tree where object files and compiled programs will be placed. It
621 can be the same as SRC_ROOT).
622 <br><br>
623
624 <dt>LLVMGCCDIR
625 <dd>
626 This is where the LLVM GCC Front End is installed.
627 <p>
628 For the pre-built GCC front end binaries, the LLVMGCCDIR is
629 <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
630</dl>
631
632</div>
633
634<!-- ======================================================================= -->
635<div class="doc_subsection">
636 <a name="environment">Setting Up Your Environment</a>
637</div>
638
639<div class="doc_text">
640
641<p>
642In order to compile and use LLVM, you may need to set some environment
643variables.
644
645<dl>
646 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
647 <dd>[Optional] This environment variable helps LLVM linking tools find the
648 locations of your bitcode libraries. It is provided only as a
649 convenience since you can specify the paths using the -L options of the
650 tools and the C/C++ front-end will automatically use the bitcode files
651 installed in its
652 <tt>lib</tt> directory.</dd>
653</dl>
654
655</div>
656
657<!-- ======================================================================= -->
658<div class="doc_subsection">
659 <a name="unpack">Unpacking the LLVM Archives</a>
660</div>
661
662<div class="doc_text">
663
664<p>
665If you have the LLVM distribution, you will need to unpack it before you
666can begin to compile it. LLVM is distributed as a set of two files: the LLVM
667suite and the LLVM GCC front end compiled for your platform. There is an
668additional test suite that is optional. Each file is a TAR archive that is
669compressed with the gzip program.
670</p>
671
672<p>The files are as follows, with <em>x.y</em> marking the version number:
673<dl>
674 <dt><tt>llvm-x.y.tar.gz</tt></dt>
675 <dd>Source release for the LLVM libraries and tools.<br/></dd>
676
677 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
678 <dd>Source release for the LLVM test suite.</dd>
679
680 <dt><tt>llvm-gcc4-x.y.source.tar.gz</tt></dt>
681 <dd>Source release of the llvm-gcc4 front end. See README.LLVM in the root
682 directory for build instructions.<br/></dd>
683
684 <dt><tt>llvm-gcc4-x.y-platform.tar.gz</tt></dt>
685 <dd>Binary release of the llvm-gcc4 front end for a specific platform.<br/></dd>
686
687</dl>
688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689</div>
690
691<!-- ======================================================================= -->
692<div class="doc_subsection">
693 <a name="checkout">Checkout LLVM from Subversion</a>
694</div>
695
696<div class="doc_text">
697
698<p>If you have access to our Subversion repository, you can get a fresh copy of
699the entire source code. All you need to do is check it out from Subvresion as
700follows:</p>
701
702<ul>
703 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
704 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
705 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
706 llvm</tt></li>
707</ul>
708
709
710<p>This will create an '<tt>llvm</tt>' directory in the current
711directory and fully populate it with the LLVM source code, Makefiles,
712test directories, and local copies of documentation files.</p>
713
714<p>If you want to get a specific release (as opposed to the most recent
715revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
716'<tt>trunk</tt>'). The following releases are located in the following
717 subdirectories of the '<tt>tags</tt>' directory:</p>
718
719<ul>
Tanya Lattner9eb3be52008-06-09 06:02:09 +0000[diff] [blame]720<li>Release 2.3: <b>RELEASE_23</b></li>
Tanya Lattner60030782008-02-12 02:42:55 +0000[diff] [blame]721<li>Release 2.2: <b>RELEASE_22</b></li>
Tanya Lattner2fad5b02007-09-28 22:50:54 +0000[diff] [blame]722<li>Release 2.1: <b>RELEASE_21</b></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]723<li>Release 2.0: <b>RELEASE_20</b></li>
724<li>Release 1.9: <b>RELEASE_19</b></li>
725<li>Release 1.8: <b>RELEASE_18</b></li>
726<li>Release 1.7: <b>RELEASE_17</b></li>
727<li>Release 1.6: <b>RELEASE_16</b></li>
728<li>Release 1.5: <b>RELEASE_15</b></li>
729<li>Release 1.4: <b>RELEASE_14</b></li>
730<li>Release 1.3: <b>RELEASE_13</b></li>
731<li>Release 1.2: <b>RELEASE_12</b></li>
732<li>Release 1.1: <b>RELEASE_11</b></li>
733<li>Release 1.0: <b>RELEASE_1</b></li>
734</ul>
735
736<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
737you get it from the Subversion repository:</p>
738
739<div class="doc_code">
740<pre>
741% cd llvm/projects
742% svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
743</pre>
744</div>
745
746<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
747configured by the LLVM configure script as well as automatically updated when
748you run <tt>svn update</tt>.</p>
749
750<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]751and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]752instructions</a> to successfully get and build the LLVM GCC front-end.</p>
753
754</div>
755
756<!-- ======================================================================= -->
757<div class="doc_subsection">
758 <a name="installcf">Install the GCC Front End</a>
759</div>
760
761<div class="doc_text">
762
763<p>Before configuring and compiling the LLVM suite, you can optionally extract the
764LLVM GCC front end from the binary distribution. It is used for running the
765llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]766<a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]767main LLVM repository.</p>
768
769<p>To install the GCC front end, do the following:</p>
770
771<ol>
772 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
773 <li><tt>gunzip --stdout llvmgcc-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
774 -</tt></li>
775</ol>
776
777<p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
778llvm-g++ to some directory in your path. When you configure LLVM, it will
779automatically detect llvm-gcc's presence (if it is in your path) enabling its
780use in llvm-test. Note that you can always build or install llvm-gcc at any
781pointer after building the main LLVM repository: just reconfigure llvm and
782llvm-test will pick it up.
783</p>
784
785<p>The binary versions of the GCC front end may not suit all of your needs. For
786example, the binary distribution may include an old version of a system header
787file, not "fix" a header file that needs to be fixed for GCC, or it may be
788linked with libraries not available on your system.</p>
789
790<p>In cases like these, you may want to try <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]791href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]792much easier now than it was in the past.</p>
793
794</div>
795
796<!-- ======================================================================= -->
797<div class="doc_subsection">
798 <a name="config">Local LLVM Configuration</a>
799</div>
800
801<div class="doc_text">
802
803 <p>Once checked out from the Subversion repository, the LLVM suite source
804 code must be
805configured via the <tt>configure</tt> script. This script sets variables in the
806various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
807<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
808the Makefiles needed to begin building LLVM.</p>
809
810<p>The following environment variables are used by the <tt>configure</tt>
811script to configure the build system:</p>
812
813<table summary="LLVM configure script environment variables">
814 <tr><th>Variable</th><th>Purpose</th></tr>
815 <tr>
816 <td>CC</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 <tr>
823 <td>CXX</td>
824 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
825 <tt>configure</tt> will look for the first GCC C++ compiler in
826 <tt>PATH</tt>. Use this variable to override
827 <tt>configure</tt>'s default behavior.</td>
828 </tr>
829</table>
830
831<p>The following options can be used to set or enable LLVM specific options:</p>
832
833<dl>
834 <dt><i>--with-llvmgccdir</i></dt>
835 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
836 The value of this option should specify the full pathname of the C/C++ Front
837 End to be used. If this option is not provided, the PATH will be searched for
838 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
839 be inferred from the path found. If the option is not given, and no llvm-gcc
840 can be found in the path then a warning will be produced by
841 <tt>configure</tt> indicating this situation. LLVM may still be built with
842 the <tt>tools-only</tt> target but attempting to build the runtime libraries
843 will fail as these libraries require llvm-gcc and llvm-g++. See
844 <a href="#installcf">Install the GCC Front End</a> for details on installing
845 the C/C++ Front End. See
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]846 <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]847 for details on building the C/C++ Front End.</dd>
848 <dt><i>--with-tclinclude</i></dt>
849 <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
850 found. Use this if you have multiple tcl installations on your machine and you
851 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
852 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
853 option, the LLVM configure script will search for the tcl 8.4 and 8.3
854 releases.
855 <br><br>
856 </dd>
857 <dt><i>--enable-optimized</i></dt>
858 <dd>
859 Enables optimized compilation by default (debugging symbols are removed
860 and GCC optimization flags are enabled). The default is to use an
861 unoptimized build (also known as a debug build).
862 <br><br>
863 </dd>
864 <dt><i>--enable-debug-runtime</i></dt>
865 <dd>
866 Enables debug symbols in the runtime libraries. The default is to strip
867 debug symbols from the runtime libraries.
868 </dd>
869 <dt><i>--enable-jit</i></dt>
870 <dd>
871 Compile the Just In Time (JIT) compiler functionality. This is not
872 available
873 on all platforms. The default is dependent on platform, so it is best
874 to explicitly enable it if you want it.
875 <br><br>
876 </dd>
877 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
878 <dd>Controls which targets will be built and linked into llc. The default
879 value for <tt>target_options</tt> is "all" which builds and links all
880 available targets. The value "host-only" can be specified to build only a
881 native compiler (no cross-compiler targets available). The "native" target is
882 selected as the target of the build host. You can also specify a comma
883 separated list of target names that you want available in llc. The target
884 names use all lower case. The current set of targets is: <br/>
885 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
886 <br><br></dd>
887 <dt><i>--enable-doxygen</i></dt>
888 <dd>Look for the doxygen program and enable construction of doxygen based
889 documentation from the source code. This is disabled by default because
890 generating the documentation can take a long time and producess 100s of
891 megabytes of output.</dd>
892 <dt><i>--with-udis86</i></dt>
893 <dd>LLVM can use external disassembler library for various purposes (now it's
894 used only for examining code produced by JIT). This option will enable usage
895 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
896 bits) disassembler library.</dd>
897</dl>
898
899<p>To configure LLVM, follow these steps:</p>
900
901<ol>
902 <li><p>Change directory into the object root directory:</p>
903
904 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
905
906 <li><p>Run the <tt>configure</tt> script located in the LLVM source
907 tree:</p>
908
909 <div class="doc_code">
910 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
911 </div></li>
912</ol>
913
914</div>
915
916<!-- ======================================================================= -->
917<div class="doc_subsection">
918 <a name="compile">Compiling the LLVM Suite Source Code</a>
919</div>
920
921<div class="doc_text">
922
923<p>Once you have configured LLVM, you can build it. There are three types of
924builds:</p>
925
926<dl>
927 <dt>Debug Builds
928 <dd>
929 These builds are the default when one types <tt>gmake</tt> (unless the
930 <tt>--enable-optimized</tt> option was used during configuration). The
931 build system will compile the tools and libraries with debugging
932 information.
933 <br><br>
934
935 <dt>Release (Optimized) Builds
936 <dd>
937 These builds are enabled with the <tt>--enable-optimized</tt> option to
938 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
939 <tt>gmake</tt> command line. For these builds, the build system will
940 compile the tools and libraries with GCC optimizations enabled and strip
941 debugging information from the libraries and executables it generates.
942 <br><br>
943
944 <dt>Profile Builds
945 <dd>
946 These builds are for use with profiling. They compile profiling
947 information into the code for use with programs like <tt>gprof</tt>.
948 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
949 on the <tt>gmake</tt> command line.
950</dl>
951
952<p>Once you have LLVM configured, you can build it by entering the
953<i>OBJ_ROOT</i> directory and issuing the following command:</p>
954
955<div class="doc_code"><pre>% gmake</pre></div>
956
957<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
958are using a version of GCC that is known not to compile LLVM.</p>
959
960<p>
961If you have multiple processors in your machine, you may wish to use some of
962the parallel build options provided by GNU Make. For example, you could use the
963command:</p>
964
965<div class="doc_code"><pre>% gmake -j2</pre></div>
966
967<p>There are several special targets which are useful when working with the LLVM
968source code:</p>
969
970<dl>
971 <dt><tt>gmake clean</tt>
972 <dd>
973 Removes all files generated by the build. This includes object files,
974 generated C/C++ files, libraries, and executables.
975 <br><br>
976
977 <dt><tt>gmake dist-clean</tt>
978 <dd>
979 Removes everything that <tt>gmake clean</tt> does, but also removes files
980 generated by <tt>configure</tt>. It attempts to return the source tree to the
981 original state in which it was shipped.
982 <br><br>
983
984 <dt><tt>gmake install</tt>
985 <dd>
986 Installs LLVM header files, libraries, tools, and documentation in a
987 hierarchy
988 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
989 defaults to <tt>/usr/local</tt>.
990 <br><br>
991
992 <dt><tt>gmake -C runtime install-bytecode</tt>
993 <dd>
994 Assuming you built LLVM into $OBJDIR, when this command is run, it will
995 install bitcode libraries into the GCC front end's bitcode library
996 directory. If you need to update your bitcode libraries,
997 this is the target to use once you've built them.
998 <br><br>
999</dl>
1000
1001<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
1002details on these <tt>make</tt> targets and descriptions of other targets
1003available.</p>
1004
1005<p>It is also possible to override default values from <tt>configure</tt> by
1006declaring variables on the command line. The following are some examples:</p>
1007
1008<dl>
1009 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1010 <dd>
1011 Perform a Release (Optimized) build.
1012 <br><br>
1013
1014 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1015 <dd>
1016 Perform a Release (Optimized) build without assertions enabled.
1017 <br><br>
1018
1019 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1020 <dd>
1021 Perform a Profiling build.
1022 <br><br>
1023
1024 <dt><tt>gmake VERBOSE=1</tt>
1025 <dd>
1026 Print what <tt>gmake</tt> is doing on standard output.
1027 <br><br>
1028
1029 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1030 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1031 the standard output. This also implies <tt>VERBOSE=1</tt>.
1032 <br><br></dd>
1033</dl>
1034
1035<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1036it and any subdirectories that it contains. Entering any directory inside the
1037LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1038that directory that is out of date.</p>
1039
1040</div>
1041
1042<!-- ======================================================================= -->
1043<div class="doc_subsection">
1044 <a name="cross-compile">Cross-Compiling LLVM</a>
1045</div>
1046
1047<div class="doc_text">
1048 <p>It is possible to cross-compile LLVM. That is, you can create LLVM
1049 executables and libraries for a platform different than the one one which you
1050 are compiling. To do this, a few additional steps are
1051 required. <sup><a href="#ccn_1">1</a></sup> To cross-compile LLVM, use
1052 these instructions:</p>
1053 <ol>
1054 <li>Configure and build LLVM as a native compiler. You will need
1055 just <tt>TableGen</tt> from that build.
1056 <ul>
1057 <li>If you have <tt>$LLVM_OBJ_ROOT=$LLVM_SRC_ROOT</tt> just execute
1058 <tt>make -C utils/TableGen</tt> after configuring.</li>
1059 <li>Otherwise you will need to monitor building process and terminate
1060 it just after <tt>TableGen</tt> was built.</li>
1061 </ul>
1062 </li>
1063 <li>Copy the TableGen binary to somewhere safe (out of your build tree).
1064 </li>
1065 <li>Configure LLVM to build with a cross-compiler. To do this, supply the
1066 configure script with <tt>--build</tt> and <tt>--host</tt> options that
1067 are different. The values of these options must be legal target triples
1068 that your GCC compiler supports.</li>
1069 <li>Put the saved <tt>TableGen</tt> executable into the
1070 into <tt>$LLVM_OBJ_ROOT/{BUILD_TYPE}/bin</tt> directory (e.g. into
1071 <tt>.../Release/bin</tt> for a Release build).</li>
1072 <li>Build LLVM as usual.</li>
1073 </ol>
1074 <p>The result of such a build will produce executables that are not executable
1075 on your build host (--build option) but can be executed on your compile host
1076 (--host option).</p>
1077 <p><b>Notes:</b></p>
1078 <div class="doc_notes">
1079 <ol>
1080 <li><a name="ccn_1">Cross-compiling</a> was tested only with Linux as
1081 build platform and Windows as host using mingw32 cross-compiler. Other
1082 combinations have not been tested.</li>
1083 </ol>
1084 </div>
1085</div>
1086
1087<!-- ======================================================================= -->
1088<div class="doc_subsection">
1089 <a name="objfiles">The Location of LLVM Object Files</a>
1090</div>
1091
1092<div class="doc_text">
1093
1094<p>The LLVM build system is capable of sharing a single LLVM source tree among
1095several LLVM builds. Hence, it is possible to build LLVM for several different
1096platforms or configurations using the same source tree.</p>
1097
1098<p>This is accomplished in the typical autoconf manner:</p>
1099
1100<ul>
1101 <li><p>Change directory to where the LLVM object files should live:</p>
1102
1103 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1104
1105 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1106 directory:</p>
1107
1108 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1109</ul>
1110
1111<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1112named after the build type:</p>
1113
1114<dl>
1115 <dt>Debug Builds
1116 <dd>
1117 <dl>
1118 <dt>Tools
1119 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1120 <dt>Libraries
1121 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1122 </dl>
1123 <br><br>
1124
1125 <dt>Release Builds
1126 <dd>
1127 <dl>
1128 <dt>Tools
1129 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1130 <dt>Libraries
1131 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1132 </dl>
1133 <br><br>
1134
1135 <dt>Profile Builds
1136 <dd>
1137 <dl>
1138 <dt>Tools
1139 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1140 <dt>Libraries
1141 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1142 </dl>
1143</dl>
1144
1145</div>
1146
1147<!-- ======================================================================= -->
1148<div class="doc_subsection">
1149 <a name="optionalconfig">Optional Configuration Items</a>
1150</div>
1151
1152<div class="doc_text">
1153
1154<p>
1155If you're running on a Linux system that supports the "<a
1156href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1157module, and you have root access on the system, you can set your system up to
1158execute LLVM bitcode files directly. To do this, use commands like this (the
1159first command may not be required if you are already using the module):</p>
1160
1161<div class="doc_code">
1162<pre>
1163$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1164$ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1165$ chmod u+x hello.bc (if needed)
1166$ ./hello.bc
1167</pre>
1168</div>
1169
1170<p>
1171This allows you to execute LLVM bitcode files directly. Thanks to Jack
1172Cummings for pointing this out!
1173</p>
1174
1175</div>
1176
1177
1178<!-- *********************************************************************** -->
1179<div class="doc_section">
1180 <a name="layout"><b>Program Layout</b></a>
1181</div>
1182<!-- *********************************************************************** -->
1183
1184<div class="doc_text">
1185
1186<p>One useful source of information about the LLVM source base is the LLVM <a
1187href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1188href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1189The following is a brief introduction to code layout:</p>
1190
1191</div>
1192
1193<!-- ======================================================================= -->
1194<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1195<div class="doc_text">
1196 <p>This directory contains some simple examples of how to use the LLVM IR and
1197 JIT.</p>
1198</div>
1199
1200<!-- ======================================================================= -->
1201<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1202<div class="doc_text">
1203
1204<p>This directory contains public header files exported from the LLVM
1205library. The three main subdirectories of this directory are:</p>
1206
1207<dl>
1208 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1209 <dd>This directory contains all of the LLVM specific header files. This
1210 directory also has subdirectories for different portions of LLVM:
1211 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1212 etc...</dd>
1213
1214 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1215 <dd>This directory contains generic support libraries that are provided with
1216 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1217 and a Command Line option processing library store their header files here.
1218 </dd>
1219
1220 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1221 <dd>This directory contains header files configured by the <tt>configure</tt>
1222 script. They wrap "standard" UNIX and C header files. Source code can
1223 include these header files which automatically take care of the conditional
1224 #includes that the <tt>configure</tt> script generates.</dd>
1225</dl>
1226</div>
1227
1228<!-- ======================================================================= -->
1229<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1230<div class="doc_text">
1231
1232<p>This directory contains most of the source files of the LLVM system. In LLVM,
1233almost all code exists in libraries, making it very easy to share code among the
1234different <a href="#tools">tools</a>.</p>
1235
1236<dl>
1237 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1238 <dd> This directory holds the core LLVM source files that implement core
1239 classes like Instruction and BasicBlock.</dd>
1240
1241 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1242 <dd>This directory holds the source code for the LLVM assembly language parser
1243 library.</dd>
1244
1245 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1246 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1247
1248 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1249 different program analyses, such as Dominator Information, Call Graphs,
1250 Induction Variables, Interval Identification, Natural Loop Identification,
1251 etc.</dd>
1252
1253 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1254 <dd> This directory contains the source code for the LLVM to LLVM program
1255 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1256 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1257 Elimination, and many others.</dd>
1258
1259 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1260 <dd> This directory contains files that describe various target architectures
1261 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1262 directory holds the X86 machine description while
1263 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1264
1265 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1266 <dd> This directory contains the major parts of the code generator: Instruction
1267 Selector, Instruction Scheduling, and Register Allocation.</dd>
1268
1269 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1270 <dd> This directory contains the source level debugger library that makes
1271 it possible to instrument LLVM programs so that a debugger could identify
1272 source code locations at which the program is executing.</dd>
1273
1274 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1275 <dd> This directory contains libraries for executing LLVM bitcode directly
1276 at runtime in both interpreted and JIT compiled fashions.</dd>
1277
1278 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1279 <dd> This directory contains the source code that corresponds to the header
1280 files located in <tt>llvm/include/Support/</tt>.</dd>
1281
1282 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1283 <dd>This directory contains the operating system abstraction layer that
1284 shields LLVM from platform-specific coding.</dd>
1285</dl>
1286
1287</div>
1288
1289<!-- ======================================================================= -->
1290<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1291<div class="doc_text">
1292 <p>This directory contains projects that are not strictly part of LLVM but are
1293 shipped with LLVM. This is also the directory where you should create your own
1294 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
Chris Lattneraf1df782008-08-11 06:13:31 +0000[diff] [blame]1295 to set up your own project.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1296</div>
1297
1298<!-- ======================================================================= -->
1299<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1300<div class="doc_text">
1301
1302<p>This directory contains libraries which are compiled into LLVM bitcode and
1303used when linking programs with the GCC front end. Most of these libraries are
1304skeleton versions of real libraries; for example, libc is a stripped down
1305version of glibc.</p>
1306
1307<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1308end to compile.</p>
1309
1310</div>
1311
1312<!-- ======================================================================= -->
1313<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1314<div class="doc_text">
1315 <p>This directory contains feature and regression tests and other basic sanity
1316 checks on the LLVM infrastructure. These are intended to run quickly and cover
1317 a lot of territory without being exhaustive.</p>
1318</div>
1319
1320<!-- ======================================================================= -->
1321<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1322<div class="doc_text">
1323 <p>This is not a directory in the normal llvm module; it is a separate
1324 Subversion
1325 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1326 This
1327 module contains a comprehensive correctness, performance, and benchmarking
1328 test
1329 suite for LLVM. It is a separate Subversion module because not every LLVM
1330 user is
1331 interested in downloading or building such a comprehensive test suite. For
1332 further details on this test suite, please see the
1333 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1334</div>
1335
1336<!-- ======================================================================= -->
1337<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1338<div class="doc_text">
1339
1340<p>The <b>tools</b> directory contains the executables built out of the
1341libraries above, which form the main part of the user interface. You can
1342always get help for a tool by typing <tt>tool_name --help</tt>. The
1343following is a brief introduction to the most important tools. More detailed
1344information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1345
1346<dl>
1347
1348 <dt><tt><b>bugpoint</b></tt></dt>
1349 <dd><tt>bugpoint</tt> is used to debug
1350 optimization passes or code generation backends by narrowing down the
1351 given test case to the minimum number of passes and/or instructions that
1352 still cause a problem, whether it is a crash or miscompilation. See <a
1353 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1354 on using <tt>bugpoint</tt>.</dd>
1355
1356 <dt><tt><b>llvmc</b></tt></dt>
1357 <dd>The LLVM Compiler Driver. This program can
1358 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1359 pre-processing, translation, optimization, assembly, and linking of programs
1360 all from one command line. <tt>llvmc</tt> also takes care of processing the
1361 dependent libraries found in bitcode. This reduces the need to get the
1362 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1363 note that this tool, while functional, is still experimental and not feature
1364 complete.</dd>
1365
1366 <dt><tt><b>llvm-ar</b></tt></dt>
1367 <dd>The archiver produces an archive containing
1368 the given LLVM bitcode files, optionally with an index for faster
1369 lookup.</dd>
1370
1371 <dt><tt><b>llvm-as</b></tt></dt>
1372 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1373 bitcode.</dd>
1374
1375 <dt><tt><b>llvm-dis</b></tt></dt>
1376 <dd>The disassembler transforms the LLVM bitcode to human readable
1377 LLVM assembly.</dd>
1378
1379 <dt><tt><b>llvm-ld</b></tt></dt>
1380 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1381 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1382 optimizations and allows optimization modules to be loaded and run so that
1383 language specific optimizations can be applied at link time.</dd>
1384
1385 <dt><tt><b>llvm-link</b></tt></dt>
1386 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1387 a single program.</dd>
1388
1389 <dt><tt><b>lli</b></tt></dt>
1390 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +0000[diff] [blame]1391 can directly execute LLVM bitcode (although very slowly...). For architectures
1392 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1393 will function as a Just-In-Time compiler (if the functionality was compiled
1394 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1395
1396 <dt><tt><b>llc</b></tt></dt>
1397 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1398 translates LLVM bitcode to a native code assembly file or to C code (with
1399 the -march=c option).</dd>
1400
1401 <dt><tt><b>llvm-gcc</b></tt></dt>
1402 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1403 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1404 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1405 usual machine code output. It works just like any other GCC compiler,
1406 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1407 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1408 separate Subversion module.</dd>
1409
1410 <dt><tt><b>opt</b></tt></dt>
1411 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1412 transformations (which are specified on the command line), and then outputs
1413 the resultant bitcode. The '<tt>opt --help</tt>' command is a good way to
1414 get a list of the program transformations available in LLVM.<br/>
1415 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1416 LLVM bitcode file and print out the results. It is primarily useful for
1417 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1418</dl>
1419</div>
1420
1421<!-- ======================================================================= -->
1422<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1423<div class="doc_text">
1424
1425<p>This directory contains utilities for working with LLVM source code, and some
1426of the utilities are actually required as part of the build process because they
1427are code generators for parts of LLVM infrastructure.</p>
1428
1429<dl>
1430 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1431 that finds differences between code that LLC generates and code that LLI
1432 generates. This is a useful tool if you are debugging one of them,
1433 assuming that the other generates correct output. For the full user
1434 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1435
1436 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1437 syntax-highlighting files which will work with Emacs and XEmacs editors,
1438 providing syntax highlighting support for LLVM assembly files and TableGen
1439 description files. For information on how to use the syntax files, consult
1440 the <tt>README</tt> file in that directory.<br><br>
1441
1442 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1443 and outputs all non-generated source files, which is useful if one wishes
1444 to do a lot of development across directories and does not want to
1445 individually find each file. One way to use it is to run, for example:
1446 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1447 tree.<br><br>
1448
1449 <dt><tt><b>llvmgrep</b></tt></dt>
1450 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1451 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1452 line. This is a very efficient way of searching the source base for a
1453 particular regular expression.</dd>
1454
1455 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1456 files in the current directory and then compiles and links the tool that
1457 is the first argument. For example, assuming you are in the directory
1458 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1459 simply running <tt>makellvm llc</tt> will make a build of the current
1460 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1461 causing a re-linking of LLC.<br><br>
1462
1463 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1464 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1465 cron script to generate nightly status reports of the functionality of
1466 tools, and the results can be seen by following the appropriate link on
1467 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1468
1469 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1470 the tool used to generate register descriptions, instruction set
1471 descriptions, and even assemblers from common TableGen description
1472 files.<br><br>
1473
1474 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1475 syntax-highlighting files which will work with the VIM editor, providing
1476 syntax highlighting support for LLVM assembly files and TableGen
1477 description files. For information on how to use the syntax files, consult
1478 the <tt>README</tt> file in that directory.<br><br>
1479
1480</dl>
1481
1482</div>
1483
1484<!-- ======================================================================= -->
1485<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1486<div class="doc_text">
1487 <p>This directory contains build scripts and project files for use with
1488 Visual C++. This allows developers on Windows to build LLVM without the need
1489 for Cygwin. The contents of this directory should be considered experimental
1490 at this time.
1491 </p>
1492</div>
1493<!-- *********************************************************************** -->
1494<div class="doc_section">
1495 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1496</div>
1497<!-- *********************************************************************** -->
1498
1499<div class="doc_text">
1500<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
1501so we only include instructiosn for llvm-gcc4.
1502</p>
1503
1504<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1505from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1506create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1507the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1508<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1509output.</p>
1510</div>
1511
1512<!-- ======================================================================= -->
1513<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1514
1515<div class="doc_text">
1516
1517<ol>
1518 <li><p>First, create a simple C file, name it 'hello.c':</p>
1519
1520<div class="doc_code">
1521<pre>
1522#include &lt;stdio.h&gt;
1523
1524int main() {
1525 printf("hello world\n");
1526 return 0;
1527}
1528</pre></div></li>
1529
1530 <li><p>Next, compile the C file into a native executable:</p>
1531
1532 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1533
1534 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1535 -c arguments work as usual (producing a native .s or .o file,
1536 respectively).</p></li>
1537
1538 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1539
1540 <div class="doc_code">
1541 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1542
1543 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1544 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1545 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1546 the bitcode file.</p>
1547
1548 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1549 </p></li>
1550
1551 <li><p>Run the program in both forms. To run the program, use:</p>
1552
1553 <div class="doc_code"><pre>% ./hello</pre></div>
1554
1555 <p>and</p>
1556
1557 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1558
1559 <p>The second examples shows how to invoke the LLVM JIT, <a
1560 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1561
1562 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1563 code:</p>
1564
1565<div class="doc_code">
1566<pre>llvm-dis &lt; hello.bc | less</pre>
1567</div></li>
1568
1569 <li><p>Compile the program to native assembly using the LLC code
1570 generator:</p>
1571
1572 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1573
1574 <li><p>Assemble the native assembly language file into a program:</p>
1575
1576<div class="doc_code">
1577<pre>
1578<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1579
1580<b>Others:</b> % gcc hello.s -o hello.native
1581</pre>
1582</div></li>
1583
1584 <li><p>Execute the native code program:</p>
1585
1586 <div class="doc_code"><pre>% ./hello.native</pre></div>
1587
1588 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1589 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1590 </li>
1591
1592</ol>
1593
1594</div>
1595
1596
1597<!-- *********************************************************************** -->
1598<div class="doc_section">
1599 <a name="problems">Common Problems</a>
1600</div>
1601<!-- *********************************************************************** -->
1602
1603<div class="doc_text">
1604
1605<p>If you are having problems building or using LLVM, or if you have any other
1606general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1607Asked Questions</a> page.</p>
1608
1609</div>
1610
1611<!-- *********************************************************************** -->
1612<div class="doc_section">
1613 <a name="links">Links</a>
1614</div>
1615<!-- *********************************************************************** -->
1616
1617<div class="doc_text">
1618
Bill Wendling08f49b92008-07-22 01:10:25 +0000[diff] [blame]1619<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]1620some simple things... there are many more interesting and complicated things
1621that you can do that aren't documented here (but we'll gladly accept a patch
1622if you want to write something up!). For more information about LLVM, check
1623out:</p>
1624
1625<ul>
1626 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1627 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1628 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1629 that Uses LLVM</a></li>
1630</ul>
1631
1632</div>
1633
1634<!-- *********************************************************************** -->
1635
1636<hr>
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1642
1643 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1644 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1645 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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