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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 Lattner99c4a2c2007-09-27 18:14:33 +0000[diff] [blame]117 <li>Install the llvm-gcc4.0 (or 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>
Tanya Lattner99c4a2c2007-09-27 18:14:33 +0000[diff] [blame]122 <ul><li>If the binary extension is ".bz" use bunzip2 instead of gunzip.</li>
123 </ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li>Add llvm-gcc's "bin" directory to your PATH variable.</li>
125 </ol></li>
126
127 <li>Get the LLVM Source Code
128 <ul>
129 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
130 <ol>
131 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
132 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
133 </ol></li>
134
135 </ul></li>
136
137 <li><b>[Optional]</b> Get the Test Suite Source Code
138 <ul>
139 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
140 <ol>
141 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
142 <li><tt>cd llvm/projects</tt>
143 <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
144 </ol></li>
145
146 </ul></li>
147
148
149 <li>Configure the LLVM Build Environment
150 <ol>
151 <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
152 <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br>
153 Some common options:
154
155 <ul>
156 <li><tt>--prefix=<i>directory</i></tt>
157 <p>Specify for <i>directory</i> the full pathname of where you
158 want the LLVM tools and libraries to be installed (default
159 <tt>/usr/local</tt>).</p></li>
160 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
161 <p>Optionally, specify for <i>directory</i> the full pathname of the
162 C/C++ front end installation to use with this LLVM configuration. If
163 not specified, the PATH will be searched.</p></li>
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>
239 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
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>
256 <td>amd64<sup><a href="#pf_3">3</a></sup></td>
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>
272 <td>Visual Studio .NET<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
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>
309<li><a name="pf_4">Build is not complete: one or more tools don't link</a></li>
310<li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
311<li><a name="pf_6">The port is done using the MSYS shell.</a>
312<a href="http://www.mingw.org/MinGWiki/">Download</a> and install
313bison (excl. M4.exe) and flex in that order. Build binutils-2.15 from source,
314if necessary. Bison &amp; flex can be also grabbed from GNUWin32 sf.net
315project.</li>
316<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
317<li><a name="pf_8">Binutils</a> up to post-2.17 has bug in bfd/cofflink.c
318 preventing LLVM from building correctly. Several workarounds have been
319 introduced into LLVM build system, but the bug can occur anytime in the
320 future. We highly recommend that you rebuild your current binutils with the
321 patch from <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=2659">
322 Binutils bugzilla</a>, if it wasn't already applied.</li>
323</ol>
324</div>
325
326<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
327mode, depending on the system (it is so large because of all the debugging
328information and the fact that the libraries are statically linked into multiple
329tools). If you do not need many of the tools and you are space-conscious,
330you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
331build requires considerably less space.</p>
332
333<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
334guaranteed to do so. If compilation is successful, the LLVM utilities should be
335able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
336generation should work as well, although the generated native code may not work
337on your platform.</p>
338
339<p>The GCC front end is not very portable at the moment. If you want to get it
340to work on another platform, you can download a copy of the source and <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame^]341href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]342
343</div>
344
345<!-- ======================================================================= -->
346<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
347<div class="doc_text">
348 <p>Compiling LLVM requires that you have several software packages
349 installed. The table below lists those required packages. The Package column
350 is the usual name for the software package that LLVM depends on. The Version
351 column provides "known to work" versions of the package. The Notes column
352 describes how LLVM uses the package and provides other details.</p>
353 <table summary="Packages required to compile LLVM">
354 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
355
356 <tr>
357 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
358 <td>3.79, 3.79.1</td>
359 <td>Makefile/build processor</td>
360 </tr>
361
362 <tr>
363 <td><a href="http://gcc.gnu.org">GCC</a></td>
364 <td>3.4.2</td>
365 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
366 </tr>
367
368 <tr>
369 <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
370 <td>4.5</td>
371 <td>For building the CFE</td>
372 </tr>
373
374 <tr>
375 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
376 <td>2.5.4</td>
377 <td>LEX compiler</td>
378 </tr>
379
380 <tr>
381 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
382 <td>1.28, 1.35, 1.75, 1.875d, 2.0, or 2.1<br>(not 1.85 or 1.875)</td>
383 <td>YACC compiler</td>
384 </tr>
385
386 <tr>
387 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
388 <td>&ge;1.3</td>
389 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
390 </tr>
391
392 <tr>
393 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
394 <td>1.4.2</td>
395 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
396 </tr>
397
398 <tr>
399 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
400 <td>8.3, 8.4</td>
401 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
402 </tr>
403
404 <tr>
405 <td><a href="http://expect.nist.gov/">expect</a></td>
406 <td>5.38.0</td>
407 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
408 </tr>
409
410 <tr>
411 <td><a href="http://www.perl.com/download.csp">perl</a></td>
412 <td>&ge;5.6.0</td>
413 <td>Nightly tester, utilities</td>
414 </tr>
415
416 <tr>
417 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
418 <td>1.4</td>
419 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
420 </tr>
421
422 <tr>
423 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
424 <td>2.59</td>
425 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
426 </tr>
427
428 <tr>
429 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
430 <td>1.9.2</td>
431 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
432 </tr>
433
434 <tr>
435 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
436 <td>1.5.10</td>
437 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
438 </tr>
439
440 </table>
441
442 <p><b>Notes:</b></p>
443 <div class="doc_notes">
444 <ol>
445 <li><a name="sf1">Only the C and C++ languages are needed so there's no
446 need to build the other languages for LLVM's purposes.</a> See
447 <a href="#brokengcc">below</a> for specific version info.</li>
448 <li><a name="sf2">You only need Subversion if you intend to build from the
449 latest LLVM sources. If you're working from a release distribution, you
450 don't need Subversion.</a></li>
451 <li><a name="sf3">Only needed if you want to run the automated test
452 suite in the <tt>llvm/test</tt> directory.</a></li>
453 <li><a name="sf4">If you want to make changes to the configure scripts,
454 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
455 or higher). You will also need automake (1.9.2). We only use aclocal
456 from that package.</a></li>
457 </ol>
458 </div>
459
460 <p>Additionally, your compilation host is expected to have the usual
461 plethora of Unix utilities. Specifically:</p>
462 <ul>
463 <li><b>ar</b> - archive library builder</li>
464 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
465 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
466 <li><b>chmod</b> - change permissions on a file</li>
467 <li><b>cat</b> - output concatenation utility</li>
468 <li><b>cp</b> - copy files</li>
469 <li><b>date</b> - print the current date/time </li>
470 <li><b>echo</b> - print to standard output</li>
471 <li><b>egrep</b> - extended regular expression search utility</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]472 <li><b>find</b> - find files/dirs in a file system</li>
473 <li><b>grep</b> - regular expression search utility</li>
474 <li><b>gzip*</b> - gzip command for distribution generation</li>
475 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
476 <li><b>install</b> - install directories/files </li>
477 <li><b>mkdir</b> - create a directory</li>
478 <li><b>mv</b> - move (rename) files</li>
479 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
480 <li><b>rm</b> - remove (delete) files and directories</li>
481 <li><b>sed</b> - stream editor for transforming output</li>
482 <li><b>sh</b> - Bourne shell for make build scripts</li>
483 <li><b>tar</b> - tape archive for distribution generation</li>
484 <li><b>test</b> - test things in file system</li>
485 <li><b>unzip*</b> - unzip command for distribution checking</li>
486 <li><b>zip*</b> - zip command for distribution generation</li>
487 </ul>
488</div>
489
490<!-- ======================================================================= -->
491<div class="doc_subsection">
492 <a name="brokengcc">Broken versions of GCC and other tools</a>
493</div>
494
495<div class="doc_text">
496
497<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
498bugs in the compiler. In particular, several versions of GCC crash when trying
499to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
500successfully with them (however, see important notes below). Other versions
501of GCC will probably work as well. GCC versions listed
502here are known to not work. If you are using one of these versions, please try
503to upgrade your GCC to something more recent. If you run into a problem with a
504version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
505us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
506of GCC you are using.
507</p>
508
509<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
510problems in the STL that effectively prevent it from compiling LLVM.
511</p>
512
Chris Lattner76bb5302008-02-13 17:50:24 +0000[diff] [blame]513<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
514a bogus template error. This was fixed in later GCCs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]515
516<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
517href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
518the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
519
520<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^]521 Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]522 to a newer version</a> if possible.</p>
523<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
524 possibly others) does not compile LLVM correctly (it appears that exception
525 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
526 to a newer version of GCC.</p>
527<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
528 code generator, causing an infinite loop in the llvm-gcc build when built
529 with optimizations enabled (i.e. a release build).</p>
530<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
531 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
532 correctly compiles LLVM at -O2. A work around is to build release LLVM
533 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
534<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
535 miscompiles portions of LLVM</a>.</p>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]536<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
537 when building with optimizations enabled. It appears to work with
538 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
539 build.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]540<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
541 miscompile LLVM.</p>
542<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
543 default with ENABLE_OPTIMIZED=1. To work around this, build with
544 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
545<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
546 compiling some files. At the time of this writing, GCC mainline (4.2)
547 did not share the problem.</p>
548<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
549 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
550 code. LLVM will appear to mostly work but will be buggy, e.g. failing
551 portions of its testsuite.</p>
552<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
553platforms compiling md5.c gets a mangled constant.</p>
554<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
555long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
556defined in a discarded section. You can safely ignore these messages as they are
557erroneous and the linkage is correct. These messages disappear using ld
5582.17.</p>
559
560<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
561href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
562causes huge link times (minutes instead of seconds) when building LLVM. We
563recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
564
565</div>
566
567
568
569<!-- *********************************************************************** -->
570<div class="doc_section">
571 <a name="starting"><b>Getting Started with LLVM</b></a>
572</div>
573<!-- *********************************************************************** -->
574
575<div class="doc_text">
576
577<p>The remainder of this guide is meant to get you up and running with
578LLVM and to give you some basic information about the LLVM environment.</p>
579
580<p>The later sections of this guide describe the <a
581href="#layout">general layout</a> of the the LLVM source tree, a <a
582href="#tutorial">simple example</a> using the LLVM tool chain, and <a
583href="#links">links</a> to find more information about LLVM or to get
584help via e-mail.</p>
585</div>
586
587<!-- ======================================================================= -->
588<div class="doc_subsection">
589 <a name="terminology">Terminology and Notation</a>
590</div>
591
592<div class="doc_text">
593
594<p>Throughout this manual, the following names are used to denote paths
595specific to the local system and working environment. <i>These are not
596environment variables you need to set but just strings used in the rest
597of this document below</i>. In any of the examples below, simply replace
598each of these names with the appropriate pathname on your local system.
599All these paths are absolute:</p>
600
601<dl>
602 <dt>SRC_ROOT
603 <dd>
604 This is the top level directory of the LLVM source tree.
605 <br><br>
606
607 <dt>OBJ_ROOT
608 <dd>
609 This is the top level directory of the LLVM object tree (i.e. the
610 tree where object files and compiled programs will be placed. It
611 can be the same as SRC_ROOT).
612 <br><br>
613
614 <dt>LLVMGCCDIR
615 <dd>
616 This is where the LLVM GCC Front End is installed.
617 <p>
618 For the pre-built GCC front end binaries, the LLVMGCCDIR is
619 <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
620</dl>
621
622</div>
623
624<!-- ======================================================================= -->
625<div class="doc_subsection">
626 <a name="environment">Setting Up Your Environment</a>
627</div>
628
629<div class="doc_text">
630
631<p>
632In order to compile and use LLVM, you may need to set some environment
633variables.
634
635<dl>
636 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
637 <dd>[Optional] This environment variable helps LLVM linking tools find the
638 locations of your bitcode libraries. It is provided only as a
639 convenience since you can specify the paths using the -L options of the
640 tools and the C/C++ front-end will automatically use the bitcode files
641 installed in its
642 <tt>lib</tt> directory.</dd>
643</dl>
644
645</div>
646
647<!-- ======================================================================= -->
648<div class="doc_subsection">
649 <a name="unpack">Unpacking the LLVM Archives</a>
650</div>
651
652<div class="doc_text">
653
654<p>
655If you have the LLVM distribution, you will need to unpack it before you
656can begin to compile it. LLVM is distributed as a set of two files: the LLVM
657suite and the LLVM GCC front end compiled for your platform. There is an
658additional test suite that is optional. Each file is a TAR archive that is
659compressed with the gzip program.
660</p>
661
662<p>The files are as follows, with <em>x.y</em> marking the version number:
663<dl>
664 <dt><tt>llvm-x.y.tar.gz</tt></dt>
665 <dd>Source release for the LLVM libraries and tools.<br/></dd>
666
667 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
668 <dd>Source release for the LLVM test suite.</dd>
669
670 <dt><tt>llvm-gcc4-x.y.source.tar.gz</tt></dt>
671 <dd>Source release of the llvm-gcc4 front end. See README.LLVM in the root
672 directory for build instructions.<br/></dd>
673
674 <dt><tt>llvm-gcc4-x.y-platform.tar.gz</tt></dt>
675 <dd>Binary release of the llvm-gcc4 front end for a specific platform.<br/></dd>
676
677</dl>
678
679<p>It is also possible to download the sources of the llvm-gcc4 front end from a
680read-only subversion mirror at
681svn://anonsvn.opensource.apple.com/svn/llvm/trunk. </p>
682
683</div>
684
685<!-- ======================================================================= -->
686<div class="doc_subsection">
687 <a name="checkout">Checkout LLVM from Subversion</a>
688</div>
689
690<div class="doc_text">
691
692<p>If you have access to our Subversion repository, you can get a fresh copy of
693the entire source code. All you need to do is check it out from Subvresion as
694follows:</p>
695
696<ul>
697 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
698 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
699 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
700 llvm</tt></li>
701</ul>
702
703
704<p>This will create an '<tt>llvm</tt>' directory in the current
705directory and fully populate it with the LLVM source code, Makefiles,
706test directories, and local copies of documentation files.</p>
707
708<p>If you want to get a specific release (as opposed to the most recent
709revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
710'<tt>trunk</tt>'). The following releases are located in the following
711 subdirectories of the '<tt>tags</tt>' directory:</p>
712
713<ul>
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>
766 <li><tt>gunzip --stdout llvmgcc-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
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>
852 Enables optimized compilation by default (debugging symbols are removed
853 and GCC optimization flags are enabled). The default is to use an
854 unoptimized build (also known as a debug build).
855 <br><br>
856 </dd>
857 <dt><i>--enable-debug-runtime</i></dt>
858 <dd>
859 Enables debug symbols in the runtime libraries. The default is to strip
860 debug symbols from the runtime libraries.
861 </dd>
862 <dt><i>--enable-jit</i></dt>
863 <dd>
864 Compile the Just In Time (JIT) compiler functionality. This is not
865 available
866 on all platforms. The default is dependent on platform, so it is best
867 to explicitly enable it if you want it.
868 <br><br>
869 </dd>
870 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
871 <dd>Controls which targets will be built and linked into llc. The default
872 value for <tt>target_options</tt> is "all" which builds and links all
873 available targets. The value "host-only" can be specified to build only a
874 native compiler (no cross-compiler targets available). The "native" target is
875 selected as the target of the build host. You can also specify a comma
876 separated list of target names that you want available in llc. The target
877 names use all lower case. The current set of targets is: <br/>
878 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
879 <br><br></dd>
880 <dt><i>--enable-doxygen</i></dt>
881 <dd>Look for the doxygen program and enable construction of doxygen based
882 documentation from the source code. This is disabled by default because
883 generating the documentation can take a long time and producess 100s of
884 megabytes of output.</dd>
885 <dt><i>--with-udis86</i></dt>
886 <dd>LLVM can use external disassembler library for various purposes (now it's
887 used only for examining code produced by JIT). This option will enable usage
888 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
889 bits) disassembler library.</dd>
890</dl>
891
892<p>To configure LLVM, follow these steps:</p>
893
894<ol>
895 <li><p>Change directory into the object root directory:</p>
896
897 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
898
899 <li><p>Run the <tt>configure</tt> script located in the LLVM source
900 tree:</p>
901
902 <div class="doc_code">
903 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
904 </div></li>
905</ol>
906
907</div>
908
909<!-- ======================================================================= -->
910<div class="doc_subsection">
911 <a name="compile">Compiling the LLVM Suite Source Code</a>
912</div>
913
914<div class="doc_text">
915
916<p>Once you have configured LLVM, you can build it. There are three types of
917builds:</p>
918
919<dl>
920 <dt>Debug Builds
921 <dd>
922 These builds are the default when one types <tt>gmake</tt> (unless the
923 <tt>--enable-optimized</tt> option was used during configuration). The
924 build system will compile the tools and libraries with debugging
925 information.
926 <br><br>
927
928 <dt>Release (Optimized) Builds
929 <dd>
930 These builds are enabled with the <tt>--enable-optimized</tt> option to
931 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
932 <tt>gmake</tt> command line. For these builds, the build system will
933 compile the tools and libraries with GCC optimizations enabled and strip
934 debugging information from the libraries and executables it generates.
935 <br><br>
936
937 <dt>Profile Builds
938 <dd>
939 These builds are for use with profiling. They compile profiling
940 information into the code for use with programs like <tt>gprof</tt>.
941 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
942 on the <tt>gmake</tt> command line.
943</dl>
944
945<p>Once you have LLVM configured, you can build it by entering the
946<i>OBJ_ROOT</i> directory and issuing the following command:</p>
947
948<div class="doc_code"><pre>% gmake</pre></div>
949
950<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
951are using a version of GCC that is known not to compile LLVM.</p>
952
953<p>
954If you have multiple processors in your machine, you may wish to use some of
955the parallel build options provided by GNU Make. For example, you could use the
956command:</p>
957
958<div class="doc_code"><pre>% gmake -j2</pre></div>
959
960<p>There are several special targets which are useful when working with the LLVM
961source code:</p>
962
963<dl>
964 <dt><tt>gmake clean</tt>
965 <dd>
966 Removes all files generated by the build. This includes object files,
967 generated C/C++ files, libraries, and executables.
968 <br><br>
969
970 <dt><tt>gmake dist-clean</tt>
971 <dd>
972 Removes everything that <tt>gmake clean</tt> does, but also removes files
973 generated by <tt>configure</tt>. It attempts to return the source tree to the
974 original state in which it was shipped.
975 <br><br>
976
977 <dt><tt>gmake install</tt>
978 <dd>
979 Installs LLVM header files, libraries, tools, and documentation in a
980 hierarchy
981 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
982 defaults to <tt>/usr/local</tt>.
983 <br><br>
984
985 <dt><tt>gmake -C runtime install-bytecode</tt>
986 <dd>
987 Assuming you built LLVM into $OBJDIR, when this command is run, it will
988 install bitcode libraries into the GCC front end's bitcode library
989 directory. If you need to update your bitcode libraries,
990 this is the target to use once you've built them.
991 <br><br>
992</dl>
993
994<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
995details on these <tt>make</tt> targets and descriptions of other targets
996available.</p>
997
998<p>It is also possible to override default values from <tt>configure</tt> by
999declaring variables on the command line. The following are some examples:</p>
1000
1001<dl>
1002 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1003 <dd>
1004 Perform a Release (Optimized) build.
1005 <br><br>
1006
1007 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1008 <dd>
1009 Perform a Release (Optimized) build without assertions enabled.
1010 <br><br>
1011
1012 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1013 <dd>
1014 Perform a Profiling build.
1015 <br><br>
1016
1017 <dt><tt>gmake VERBOSE=1</tt>
1018 <dd>
1019 Print what <tt>gmake</tt> is doing on standard output.
1020 <br><br>
1021
1022 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1023 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1024 the standard output. This also implies <tt>VERBOSE=1</tt>.
1025 <br><br></dd>
1026</dl>
1027
1028<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1029it and any subdirectories that it contains. Entering any directory inside the
1030LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1031that directory that is out of date.</p>
1032
1033</div>
1034
1035<!-- ======================================================================= -->
1036<div class="doc_subsection">
1037 <a name="cross-compile">Cross-Compiling LLVM</a>
1038</div>
1039
1040<div class="doc_text">
1041 <p>It is possible to cross-compile LLVM. That is, you can create LLVM
1042 executables and libraries for a platform different than the one one which you
1043 are compiling. To do this, a few additional steps are
1044 required. <sup><a href="#ccn_1">1</a></sup> To cross-compile LLVM, use
1045 these instructions:</p>
1046 <ol>
1047 <li>Configure and build LLVM as a native compiler. You will need
1048 just <tt>TableGen</tt> from that build.
1049 <ul>
1050 <li>If you have <tt>$LLVM_OBJ_ROOT=$LLVM_SRC_ROOT</tt> just execute
1051 <tt>make -C utils/TableGen</tt> after configuring.</li>
1052 <li>Otherwise you will need to monitor building process and terminate
1053 it just after <tt>TableGen</tt> was built.</li>
1054 </ul>
1055 </li>
1056 <li>Copy the TableGen binary to somewhere safe (out of your build tree).
1057 </li>
1058 <li>Configure LLVM to build with a cross-compiler. To do this, supply the
1059 configure script with <tt>--build</tt> and <tt>--host</tt> options that
1060 are different. The values of these options must be legal target triples
1061 that your GCC compiler supports.</li>
1062 <li>Put the saved <tt>TableGen</tt> executable into the
1063 into <tt>$LLVM_OBJ_ROOT/{BUILD_TYPE}/bin</tt> directory (e.g. into
1064 <tt>.../Release/bin</tt> for a Release build).</li>
1065 <li>Build LLVM as usual.</li>
1066 </ol>
1067 <p>The result of such a build will produce executables that are not executable
1068 on your build host (--build option) but can be executed on your compile host
1069 (--host option).</p>
1070 <p><b>Notes:</b></p>
1071 <div class="doc_notes">
1072 <ol>
1073 <li><a name="ccn_1">Cross-compiling</a> was tested only with Linux as
1074 build platform and Windows as host using mingw32 cross-compiler. Other
1075 combinations have not been tested.</li>
1076 </ol>
1077 </div>
1078</div>
1079
1080<!-- ======================================================================= -->
1081<div class="doc_subsection">
1082 <a name="objfiles">The Location of LLVM Object Files</a>
1083</div>
1084
1085<div class="doc_text">
1086
1087<p>The LLVM build system is capable of sharing a single LLVM source tree among
1088several LLVM builds. Hence, it is possible to build LLVM for several different
1089platforms or configurations using the same source tree.</p>
1090
1091<p>This is accomplished in the typical autoconf manner:</p>
1092
1093<ul>
1094 <li><p>Change directory to where the LLVM object files should live:</p>
1095
1096 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1097
1098 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1099 directory:</p>
1100
1101 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1102</ul>
1103
1104<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1105named after the build type:</p>
1106
1107<dl>
1108 <dt>Debug Builds
1109 <dd>
1110 <dl>
1111 <dt>Tools
1112 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1113 <dt>Libraries
1114 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1115 </dl>
1116 <br><br>
1117
1118 <dt>Release Builds
1119 <dd>
1120 <dl>
1121 <dt>Tools
1122 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1123 <dt>Libraries
1124 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1125 </dl>
1126 <br><br>
1127
1128 <dt>Profile Builds
1129 <dd>
1130 <dl>
1131 <dt>Tools
1132 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1133 <dt>Libraries
1134 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1135 </dl>
1136</dl>
1137
1138</div>
1139
1140<!-- ======================================================================= -->
1141<div class="doc_subsection">
1142 <a name="optionalconfig">Optional Configuration Items</a>
1143</div>
1144
1145<div class="doc_text">
1146
1147<p>
1148If you're running on a Linux system that supports the "<a
1149href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1150module, and you have root access on the system, you can set your system up to
1151execute LLVM bitcode files directly. To do this, use commands like this (the
1152first command may not be required if you are already using the module):</p>
1153
1154<div class="doc_code">
1155<pre>
1156$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1157$ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1158$ chmod u+x hello.bc (if needed)
1159$ ./hello.bc
1160</pre>
1161</div>
1162
1163<p>
1164This allows you to execute LLVM bitcode files directly. Thanks to Jack
1165Cummings for pointing this out!
1166</p>
1167
1168</div>
1169
1170
1171<!-- *********************************************************************** -->
1172<div class="doc_section">
1173 <a name="layout"><b>Program Layout</b></a>
1174</div>
1175<!-- *********************************************************************** -->
1176
1177<div class="doc_text">
1178
1179<p>One useful source of information about the LLVM source base is the LLVM <a
1180href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1181href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1182The following is a brief introduction to code layout:</p>
1183
1184</div>
1185
1186<!-- ======================================================================= -->
1187<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1188<div class="doc_text">
1189 <p>This directory contains some simple examples of how to use the LLVM IR and
1190 JIT.</p>
1191</div>
1192
1193<!-- ======================================================================= -->
1194<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1195<div class="doc_text">
1196
1197<p>This directory contains public header files exported from the LLVM
1198library. The three main subdirectories of this directory are:</p>
1199
1200<dl>
1201 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1202 <dd>This directory contains all of the LLVM specific header files. This
1203 directory also has subdirectories for different portions of LLVM:
1204 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1205 etc...</dd>
1206
1207 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1208 <dd>This directory contains generic support libraries that are provided with
1209 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1210 and a Command Line option processing library store their header files here.
1211 </dd>
1212
1213 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1214 <dd>This directory contains header files configured by the <tt>configure</tt>
1215 script. They wrap "standard" UNIX and C header files. Source code can
1216 include these header files which automatically take care of the conditional
1217 #includes that the <tt>configure</tt> script generates.</dd>
1218</dl>
1219</div>
1220
1221<!-- ======================================================================= -->
1222<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1223<div class="doc_text">
1224
1225<p>This directory contains most of the source files of the LLVM system. In LLVM,
1226almost all code exists in libraries, making it very easy to share code among the
1227different <a href="#tools">tools</a>.</p>
1228
1229<dl>
1230 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1231 <dd> This directory holds the core LLVM source files that implement core
1232 classes like Instruction and BasicBlock.</dd>
1233
1234 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1235 <dd>This directory holds the source code for the LLVM assembly language parser
1236 library.</dd>
1237
1238 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1239 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1240
1241 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1242 different program analyses, such as Dominator Information, Call Graphs,
1243 Induction Variables, Interval Identification, Natural Loop Identification,
1244 etc.</dd>
1245
1246 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1247 <dd> This directory contains the source code for the LLVM to LLVM program
1248 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1249 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1250 Elimination, and many others.</dd>
1251
1252 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1253 <dd> This directory contains files that describe various target architectures
1254 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1255 directory holds the X86 machine description while
1256 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1257
1258 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1259 <dd> This directory contains the major parts of the code generator: Instruction
1260 Selector, Instruction Scheduling, and Register Allocation.</dd>
1261
1262 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1263 <dd> This directory contains the source level debugger library that makes
1264 it possible to instrument LLVM programs so that a debugger could identify
1265 source code locations at which the program is executing.</dd>
1266
1267 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1268 <dd> This directory contains libraries for executing LLVM bitcode directly
1269 at runtime in both interpreted and JIT compiled fashions.</dd>
1270
1271 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1272 <dd> This directory contains the source code that corresponds to the header
1273 files located in <tt>llvm/include/Support/</tt>.</dd>
1274
1275 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1276 <dd>This directory contains the operating system abstraction layer that
1277 shields LLVM from platform-specific coding.</dd>
1278</dl>
1279
1280</div>
1281
1282<!-- ======================================================================= -->
1283<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1284<div class="doc_text">
1285 <p>This directory contains projects that are not strictly part of LLVM but are
1286 shipped with LLVM. This is also the directory where you should create your own
1287 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1288 to set up your own project. See <tt>llvm/projects/Stacker</tt> for a fully
1289 functional example of a compiler front end.</p>
1290</div>
1291
1292<!-- ======================================================================= -->
1293<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1294<div class="doc_text">
1295
1296<p>This directory contains libraries which are compiled into LLVM bitcode and
1297used when linking programs with the GCC front end. Most of these libraries are
1298skeleton versions of real libraries; for example, libc is a stripped down
1299version of glibc.</p>
1300
1301<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1302end to compile.</p>
1303
1304</div>
1305
1306<!-- ======================================================================= -->
1307<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1308<div class="doc_text">
1309 <p>This directory contains feature and regression tests and other basic sanity
1310 checks on the LLVM infrastructure. These are intended to run quickly and cover
1311 a lot of territory without being exhaustive.</p>
1312</div>
1313
1314<!-- ======================================================================= -->
1315<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1316<div class="doc_text">
1317 <p>This is not a directory in the normal llvm module; it is a separate
1318 Subversion
1319 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1320 This
1321 module contains a comprehensive correctness, performance, and benchmarking
1322 test
1323 suite for LLVM. It is a separate Subversion module because not every LLVM
1324 user is
1325 interested in downloading or building such a comprehensive test suite. For
1326 further details on this test suite, please see the
1327 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1328</div>
1329
1330<!-- ======================================================================= -->
1331<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1332<div class="doc_text">
1333
1334<p>The <b>tools</b> directory contains the executables built out of the
1335libraries above, which form the main part of the user interface. You can
1336always get help for a tool by typing <tt>tool_name --help</tt>. The
1337following is a brief introduction to the most important tools. More detailed
1338information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1339
1340<dl>
1341
1342 <dt><tt><b>bugpoint</b></tt></dt>
1343 <dd><tt>bugpoint</tt> is used to debug
1344 optimization passes or code generation backends by narrowing down the
1345 given test case to the minimum number of passes and/or instructions that
1346 still cause a problem, whether it is a crash or miscompilation. See <a
1347 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1348 on using <tt>bugpoint</tt>.</dd>
1349
1350 <dt><tt><b>llvmc</b></tt></dt>
1351 <dd>The LLVM Compiler Driver. This program can
1352 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1353 pre-processing, translation, optimization, assembly, and linking of programs
1354 all from one command line. <tt>llvmc</tt> also takes care of processing the
1355 dependent libraries found in bitcode. This reduces the need to get the
1356 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1357 note that this tool, while functional, is still experimental and not feature
1358 complete.</dd>
1359
1360 <dt><tt><b>llvm-ar</b></tt></dt>
1361 <dd>The archiver produces an archive containing
1362 the given LLVM bitcode files, optionally with an index for faster
1363 lookup.</dd>
1364
1365 <dt><tt><b>llvm-as</b></tt></dt>
1366 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1367 bitcode.</dd>
1368
1369 <dt><tt><b>llvm-dis</b></tt></dt>
1370 <dd>The disassembler transforms the LLVM bitcode to human readable
1371 LLVM assembly.</dd>
1372
1373 <dt><tt><b>llvm-ld</b></tt></dt>
1374 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1375 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1376 optimizations and allows optimization modules to be loaded and run so that
1377 language specific optimizations can be applied at link time.</dd>
1378
1379 <dt><tt><b>llvm-link</b></tt></dt>
1380 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1381 a single program.</dd>
1382
1383 <dt><tt><b>lli</b></tt></dt>
1384 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +0000[diff] [blame]1385 can directly execute LLVM bitcode (although very slowly...). For architectures
1386 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1387 will function as a Just-In-Time compiler (if the functionality was compiled
1388 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1389
1390 <dt><tt><b>llc</b></tt></dt>
1391 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1392 translates LLVM bitcode to a native code assembly file or to C code (with
1393 the -march=c option).</dd>
1394
1395 <dt><tt><b>llvm-gcc</b></tt></dt>
1396 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1397 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1398 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1399 usual machine code output. It works just like any other GCC compiler,
1400 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1401 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1402 separate Subversion module.</dd>
1403
1404 <dt><tt><b>opt</b></tt></dt>
1405 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1406 transformations (which are specified on the command line), and then outputs
1407 the resultant bitcode. The '<tt>opt --help</tt>' command is a good way to
1408 get a list of the program transformations available in LLVM.<br/>
1409 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1410 LLVM bitcode file and print out the results. It is primarily useful for
1411 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1412</dl>
1413</div>
1414
1415<!-- ======================================================================= -->
1416<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1417<div class="doc_text">
1418
1419<p>This directory contains utilities for working with LLVM source code, and some
1420of the utilities are actually required as part of the build process because they
1421are code generators for parts of LLVM infrastructure.</p>
1422
1423<dl>
1424 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1425 that finds differences between code that LLC generates and code that LLI
1426 generates. This is a useful tool if you are debugging one of them,
1427 assuming that the other generates correct output. For the full user
1428 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1429
1430 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1431 syntax-highlighting files which will work with Emacs and XEmacs editors,
1432 providing syntax highlighting support for LLVM assembly files and TableGen
1433 description files. For information on how to use the syntax files, consult
1434 the <tt>README</tt> file in that directory.<br><br>
1435
1436 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1437 and outputs all non-generated source files, which is useful if one wishes
1438 to do a lot of development across directories and does not want to
1439 individually find each file. One way to use it is to run, for example:
1440 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1441 tree.<br><br>
1442
1443 <dt><tt><b>llvmgrep</b></tt></dt>
1444 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1445 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1446 line. This is a very efficient way of searching the source base for a
1447 particular regular expression.</dd>
1448
1449 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1450 files in the current directory and then compiles and links the tool that
1451 is the first argument. For example, assuming you are in the directory
1452 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1453 simply running <tt>makellvm llc</tt> will make a build of the current
1454 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1455 causing a re-linking of LLC.<br><br>
1456
1457 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1458 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1459 cron script to generate nightly status reports of the functionality of
1460 tools, and the results can be seen by following the appropriate link on
1461 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1462
1463 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1464 the tool used to generate register descriptions, instruction set
1465 descriptions, and even assemblers from common TableGen description
1466 files.<br><br>
1467
1468 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1469 syntax-highlighting files which will work with the VIM editor, providing
1470 syntax highlighting support for LLVM assembly files and TableGen
1471 description files. For information on how to use the syntax files, consult
1472 the <tt>README</tt> file in that directory.<br><br>
1473
1474</dl>
1475
1476</div>
1477
1478<!-- ======================================================================= -->
1479<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1480<div class="doc_text">
1481 <p>This directory contains build scripts and project files for use with
1482 Visual C++. This allows developers on Windows to build LLVM without the need
1483 for Cygwin. The contents of this directory should be considered experimental
1484 at this time.
1485 </p>
1486</div>
1487<!-- *********************************************************************** -->
1488<div class="doc_section">
1489 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1490</div>
1491<!-- *********************************************************************** -->
1492
1493<div class="doc_text">
1494<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
1495so we only include instructiosn for llvm-gcc4.
1496</p>
1497
1498<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1499from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1500create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1501the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1502<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1503output.</p>
1504</div>
1505
1506<!-- ======================================================================= -->
1507<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1508
1509<div class="doc_text">
1510
1511<ol>
1512 <li><p>First, create a simple C file, name it 'hello.c':</p>
1513
1514<div class="doc_code">
1515<pre>
1516#include &lt;stdio.h&gt;
1517
1518int main() {
1519 printf("hello world\n");
1520 return 0;
1521}
1522</pre></div></li>
1523
1524 <li><p>Next, compile the C file into a native executable:</p>
1525
1526 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1527
1528 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1529 -c arguments work as usual (producing a native .s or .o file,
1530 respectively).</p></li>
1531
1532 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1533
1534 <div class="doc_code">
1535 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1536
1537 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1538 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1539 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1540 the bitcode file.</p>
1541
1542 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1543 </p></li>
1544
1545 <li><p>Run the program in both forms. To run the program, use:</p>
1546
1547 <div class="doc_code"><pre>% ./hello</pre></div>
1548
1549 <p>and</p>
1550
1551 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1552
1553 <p>The second examples shows how to invoke the LLVM JIT, <a
1554 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1555
1556 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1557 code:</p>
1558
1559<div class="doc_code">
1560<pre>llvm-dis &lt; hello.bc | less</pre>
1561</div></li>
1562
1563 <li><p>Compile the program to native assembly using the LLC code
1564 generator:</p>
1565
1566 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1567
1568 <li><p>Assemble the native assembly language file into a program:</p>
1569
1570<div class="doc_code">
1571<pre>
1572<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1573
1574<b>Others:</b> % gcc hello.s -o hello.native
1575</pre>
1576</div></li>
1577
1578 <li><p>Execute the native code program:</p>
1579
1580 <div class="doc_code"><pre>% ./hello.native</pre></div>
1581
1582 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1583 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1584 </li>
1585
1586</ol>
1587
1588</div>
1589
1590
1591<!-- *********************************************************************** -->
1592<div class="doc_section">
1593 <a name="problems">Common Problems</a>
1594</div>
1595<!-- *********************************************************************** -->
1596
1597<div class="doc_text">
1598
1599<p>If you are having problems building or using LLVM, or if you have any other
1600general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1601Asked Questions</a> page.</p>
1602
1603</div>
1604
1605<!-- *********************************************************************** -->
1606<div class="doc_section">
1607 <a name="links">Links</a>
1608</div>
1609<!-- *********************************************************************** -->
1610
1611<div class="doc_text">
1612
1613<p>This document is just an <b>introduction</b> to how to use LLVM to do
1614some simple things... there are many more interesting and complicated things
1615that you can do that aren't documented here (but we'll gladly accept a patch
1616if you want to write something up!). For more information about LLVM, check
1617out:</p>
1618
1619<ul>
1620 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1621 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1622 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1623 that Uses LLVM</a></li>
1624</ul>
1625
1626</div>
1627
1628<!-- *********************************************************************** -->
1629
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1631<address>
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1636
1637 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1638 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1639 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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