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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>
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>
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]239 <td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]240 <td>x86</td>
241 <td>GCC</td>
242
243</tr>
244<tr>
245 <td>Cygwin/Win32</td>
246 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a></sup></td>
247 <td>GCC 3.4.X, binutils 2.15</td>
248</tr>
249<tr>
250 <td>MinGW/Win32</td>
251 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,<a href="#pf_8">8</a></sup></td>
252 <td>GCC 3.4.X, binutils 2.15</td>
253</tr>
254<tr>
255 <td>Linux</td>
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>
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]323<li><a name="pf_9">XCode 2.5 and gcc 4.0.1 (Apple Build 5370) will trip
324 internal LLVM assert messages when compiled for Release at optimization
325 levels greater than 0 (i.e., <i>&ldquo;-O1&rdquo;</i> and higher).
326 Add <i>OPTIMIZE_OPTION=&quot;-O0&quot;</i> to the build command line
327 if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]328</ol>
329</div>
330
331<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
332mode, depending on the system (it is so large because of all the debugging
333information and the fact that the libraries are statically linked into multiple
334tools). If you do not need many of the tools and you are space-conscious,
335you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
336build requires considerably less space.</p>
337
338<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
339guaranteed to do so. If compilation is successful, the LLVM utilities should be
340able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
341generation should work as well, although the generated native code may not work
342on your platform.</p>
343
344<p>The GCC front end is not very portable at the moment. If you want to get it
345to work on another platform, you can download a copy of the source and <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]346href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
348</div>
349
350<!-- ======================================================================= -->
351<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
352<div class="doc_text">
353 <p>Compiling LLVM requires that you have several software packages
354 installed. The table below lists those required packages. The Package column
355 is the usual name for the software package that LLVM depends on. The Version
356 column provides "known to work" versions of the package. The Notes column
357 describes how LLVM uses the package and provides other details.</p>
358 <table summary="Packages required to compile LLVM">
359 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
360
361 <tr>
362 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
363 <td>3.79, 3.79.1</td>
364 <td>Makefile/build processor</td>
365 </tr>
366
367 <tr>
368 <td><a href="http://gcc.gnu.org">GCC</a></td>
369 <td>3.4.2</td>
370 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
371 </tr>
372
373 <tr>
374 <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
375 <td>4.5</td>
376 <td>For building the CFE</td>
377 </tr>
378
379 <tr>
380 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
381 <td>2.5.4</td>
382 <td>LEX compiler</td>
383 </tr>
384
385 <tr>
386 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
387 <td>1.28, 1.35, 1.75, 1.875d, 2.0, or 2.1<br>(not 1.85 or 1.875)</td>
388 <td>YACC compiler</td>
389 </tr>
390
391 <tr>
392 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
393 <td>&ge;1.3</td>
394 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
395 </tr>
396
397 <tr>
398 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
399 <td>1.4.2</td>
400 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
401 </tr>
402
403 <tr>
404 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
405 <td>8.3, 8.4</td>
406 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
407 </tr>
408
409 <tr>
410 <td><a href="http://expect.nist.gov/">expect</a></td>
411 <td>5.38.0</td>
412 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
413 </tr>
414
415 <tr>
416 <td><a href="http://www.perl.com/download.csp">perl</a></td>
417 <td>&ge;5.6.0</td>
418 <td>Nightly tester, utilities</td>
419 </tr>
420
421 <tr>
422 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
423 <td>1.4</td>
424 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
425 </tr>
426
427 <tr>
428 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
429 <td>2.59</td>
430 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
431 </tr>
432
433 <tr>
434 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
435 <td>1.9.2</td>
436 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
437 </tr>
438
439 <tr>
440 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
441 <td>1.5.10</td>
442 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
443 </tr>
444
445 </table>
446
447 <p><b>Notes:</b></p>
448 <div class="doc_notes">
449 <ol>
450 <li><a name="sf1">Only the C and C++ languages are needed so there's no
451 need to build the other languages for LLVM's purposes.</a> See
452 <a href="#brokengcc">below</a> for specific version info.</li>
453 <li><a name="sf2">You only need Subversion if you intend to build from the
454 latest LLVM sources. If you're working from a release distribution, you
455 don't need Subversion.</a></li>
456 <li><a name="sf3">Only needed if you want to run the automated test
457 suite in the <tt>llvm/test</tt> directory.</a></li>
458 <li><a name="sf4">If you want to make changes to the configure scripts,
459 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
460 or higher). You will also need automake (1.9.2). We only use aclocal
461 from that package.</a></li>
462 </ol>
463 </div>
464
465 <p>Additionally, your compilation host is expected to have the usual
466 plethora of Unix utilities. Specifically:</p>
467 <ul>
468 <li><b>ar</b> - archive library builder</li>
469 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
470 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
471 <li><b>chmod</b> - change permissions on a file</li>
472 <li><b>cat</b> - output concatenation utility</li>
473 <li><b>cp</b> - copy files</li>
474 <li><b>date</b> - print the current date/time </li>
475 <li><b>echo</b> - print to standard output</li>
476 <li><b>egrep</b> - extended regular expression search utility</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]477 <li><b>find</b> - find files/dirs in a file system</li>
478 <li><b>grep</b> - regular expression search utility</li>
479 <li><b>gzip*</b> - gzip command for distribution generation</li>
480 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
481 <li><b>install</b> - install directories/files </li>
482 <li><b>mkdir</b> - create a directory</li>
483 <li><b>mv</b> - move (rename) files</li>
484 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
485 <li><b>rm</b> - remove (delete) files and directories</li>
486 <li><b>sed</b> - stream editor for transforming output</li>
487 <li><b>sh</b> - Bourne shell for make build scripts</li>
488 <li><b>tar</b> - tape archive for distribution generation</li>
489 <li><b>test</b> - test things in file system</li>
490 <li><b>unzip*</b> - unzip command for distribution checking</li>
491 <li><b>zip*</b> - zip command for distribution generation</li>
492 </ul>
493</div>
494
495<!-- ======================================================================= -->
496<div class="doc_subsection">
497 <a name="brokengcc">Broken versions of GCC and other tools</a>
498</div>
499
500<div class="doc_text">
501
502<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
503bugs in the compiler. In particular, several versions of GCC crash when trying
504to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
505successfully with them (however, see important notes below). Other versions
506of GCC will probably work as well. GCC versions listed
507here are known to not work. If you are using one of these versions, please try
508to upgrade your GCC to something more recent. If you run into a problem with a
509version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
510us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
511of GCC you are using.
512</p>
513
514<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
515problems in the STL that effectively prevent it from compiling LLVM.
516</p>
517
Chris Lattner76bb5302008-02-13 17:50:24 +0000[diff] [blame]518<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
519a bogus template error. This was fixed in later GCCs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]520
521<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
522href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
523the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
524
525<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]526 Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]527 to a newer version</a> if possible.</p>
528<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
529 possibly others) does not compile LLVM correctly (it appears that exception
530 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
531 to a newer version of GCC.</p>
532<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
533 code generator, causing an infinite loop in the llvm-gcc build when built
534 with optimizations enabled (i.e. a release build).</p>
535<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
536 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
537 correctly compiles LLVM at -O2. A work around is to build release LLVM
538 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
539<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
540 miscompiles portions of LLVM</a>.</p>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]541<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
542 when building with optimizations enabled. It appears to work with
543 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
544 build.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]545<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
546 miscompile LLVM.</p>
547<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
548 default with ENABLE_OPTIMIZED=1. To work around this, build with
549 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
550<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
551 compiling some files. At the time of this writing, GCC mainline (4.2)
552 did not share the problem.</p>
553<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
554 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
555 code. LLVM will appear to mostly work but will be buggy, e.g. failing
556 portions of its testsuite.</p>
557<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
558platforms compiling md5.c gets a mangled constant.</p>
559<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
560long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
561defined in a discarded section. You can safely ignore these messages as they are
562erroneous and the linkage is correct. These messages disappear using ld
5632.17.</p>
564
565<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
566href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
567causes huge link times (minutes instead of seconds) when building LLVM. We
568recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
569
570</div>
571
572
573
574<!-- *********************************************************************** -->
575<div class="doc_section">
576 <a name="starting"><b>Getting Started with LLVM</b></a>
577</div>
578<!-- *********************************************************************** -->
579
580<div class="doc_text">
581
582<p>The remainder of this guide is meant to get you up and running with
583LLVM and to give you some basic information about the LLVM environment.</p>
584
585<p>The later sections of this guide describe the <a
586href="#layout">general layout</a> of the the LLVM source tree, a <a
587href="#tutorial">simple example</a> using the LLVM tool chain, and <a
588href="#links">links</a> to find more information about LLVM or to get
589help via e-mail.</p>
590</div>
591
592<!-- ======================================================================= -->
593<div class="doc_subsection">
594 <a name="terminology">Terminology and Notation</a>
595</div>
596
597<div class="doc_text">
598
599<p>Throughout this manual, the following names are used to denote paths
600specific to the local system and working environment. <i>These are not
601environment variables you need to set but just strings used in the rest
602of this document below</i>. In any of the examples below, simply replace
603each of these names with the appropriate pathname on your local system.
604All these paths are absolute:</p>
605
606<dl>
607 <dt>SRC_ROOT
608 <dd>
609 This is the top level directory of the LLVM source tree.
610 <br><br>
611
612 <dt>OBJ_ROOT
613 <dd>
614 This is the top level directory of the LLVM object tree (i.e. the
615 tree where object files and compiled programs will be placed. It
616 can be the same as SRC_ROOT).
617 <br><br>
618
619 <dt>LLVMGCCDIR
620 <dd>
621 This is where the LLVM GCC Front End is installed.
622 <p>
623 For the pre-built GCC front end binaries, the LLVMGCCDIR is
624 <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
625</dl>
626
627</div>
628
629<!-- ======================================================================= -->
630<div class="doc_subsection">
631 <a name="environment">Setting Up Your Environment</a>
632</div>
633
634<div class="doc_text">
635
636<p>
637In order to compile and use LLVM, you may need to set some environment
638variables.
639
640<dl>
641 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
642 <dd>[Optional] This environment variable helps LLVM linking tools find the
643 locations of your bitcode libraries. It is provided only as a
644 convenience since you can specify the paths using the -L options of the
645 tools and the C/C++ front-end will automatically use the bitcode files
646 installed in its
647 <tt>lib</tt> directory.</dd>
648</dl>
649
650</div>
651
652<!-- ======================================================================= -->
653<div class="doc_subsection">
654 <a name="unpack">Unpacking the LLVM Archives</a>
655</div>
656
657<div class="doc_text">
658
659<p>
660If you have the LLVM distribution, you will need to unpack it before you
661can begin to compile it. LLVM is distributed as a set of two files: the LLVM
662suite and the LLVM GCC front end compiled for your platform. There is an
663additional test suite that is optional. Each file is a TAR archive that is
664compressed with the gzip program.
665</p>
666
667<p>The files are as follows, with <em>x.y</em> marking the version number:
668<dl>
669 <dt><tt>llvm-x.y.tar.gz</tt></dt>
670 <dd>Source release for the LLVM libraries and tools.<br/></dd>
671
672 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
673 <dd>Source release for the LLVM test suite.</dd>
674
675 <dt><tt>llvm-gcc4-x.y.source.tar.gz</tt></dt>
676 <dd>Source release of the llvm-gcc4 front end. See README.LLVM in the root
677 directory for build instructions.<br/></dd>
678
679 <dt><tt>llvm-gcc4-x.y-platform.tar.gz</tt></dt>
680 <dd>Binary release of the llvm-gcc4 front end for a specific platform.<br/></dd>
681
682</dl>
683
684<p>It is also possible to download the sources of the llvm-gcc4 front end from a
685read-only subversion mirror at
686svn://anonsvn.opensource.apple.com/svn/llvm/trunk. </p>
687
688</div>
689
690<!-- ======================================================================= -->
691<div class="doc_subsection">
692 <a name="checkout">Checkout LLVM from Subversion</a>
693</div>
694
695<div class="doc_text">
696
697<p>If you have access to our Subversion repository, you can get a fresh copy of
698the entire source code. All you need to do is check it out from Subvresion as
699follows:</p>
700
701<ul>
702 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
703 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
704 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
705 llvm</tt></li>
706</ul>
707
708
709<p>This will create an '<tt>llvm</tt>' directory in the current
710directory and fully populate it with the LLVM source code, Makefiles,
711test directories, and local copies of documentation files.</p>
712
713<p>If you want to get a specific release (as opposed to the most recent
714revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
715'<tt>trunk</tt>'). The following releases are located in the following
716 subdirectories of the '<tt>tags</tt>' directory:</p>
717
718<ul>
Tanya Lattner60030782008-02-12 02:42:55 +0000[diff] [blame]719<li>Release 2.2: <b>RELEASE_22</b></li>
Tanya Lattner2fad5b02007-09-28 22:50:54 +0000[diff] [blame]720<li>Release 2.1: <b>RELEASE_21</b></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]721<li>Release 2.0: <b>RELEASE_20</b></li>
722<li>Release 1.9: <b>RELEASE_19</b></li>
723<li>Release 1.8: <b>RELEASE_18</b></li>
724<li>Release 1.7: <b>RELEASE_17</b></li>
725<li>Release 1.6: <b>RELEASE_16</b></li>
726<li>Release 1.5: <b>RELEASE_15</b></li>
727<li>Release 1.4: <b>RELEASE_14</b></li>
728<li>Release 1.3: <b>RELEASE_13</b></li>
729<li>Release 1.2: <b>RELEASE_12</b></li>
730<li>Release 1.1: <b>RELEASE_11</b></li>
731<li>Release 1.0: <b>RELEASE_1</b></li>
732</ul>
733
734<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
735you get it from the Subversion repository:</p>
736
737<div class="doc_code">
738<pre>
739% cd llvm/projects
740% svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
741</pre>
742</div>
743
744<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
745configured by the LLVM configure script as well as automatically updated when
746you run <tt>svn update</tt>.</p>
747
748<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]749and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]750instructions</a> to successfully get and build the LLVM GCC front-end.</p>
751
752</div>
753
754<!-- ======================================================================= -->
755<div class="doc_subsection">
756 <a name="installcf">Install the GCC Front End</a>
757</div>
758
759<div class="doc_text">
760
761<p>Before configuring and compiling the LLVM suite, you can optionally extract the
762LLVM GCC front end from the binary distribution. It is used for running the
763llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]764<a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]765main LLVM repository.</p>
766
767<p>To install the GCC front end, do the following:</p>
768
769<ol>
770 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
771 <li><tt>gunzip --stdout llvmgcc-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
772 -</tt></li>
773</ol>
774
775<p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
776llvm-g++ to some directory in your path. When you configure LLVM, it will
777automatically detect llvm-gcc's presence (if it is in your path) enabling its
778use in llvm-test. Note that you can always build or install llvm-gcc at any
779pointer after building the main LLVM repository: just reconfigure llvm and
780llvm-test will pick it up.
781</p>
782
783<p>The binary versions of the GCC front end may not suit all of your needs. For
784example, the binary distribution may include an old version of a system header
785file, not "fix" a header file that needs to be fixed for GCC, or it may be
786linked with libraries not available on your system.</p>
787
788<p>In cases like these, you may want to try <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]789href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]790much easier now than it was in the past.</p>
791
792</div>
793
794<!-- ======================================================================= -->
795<div class="doc_subsection">
796 <a name="config">Local LLVM Configuration</a>
797</div>
798
799<div class="doc_text">
800
801 <p>Once checked out from the Subversion repository, the LLVM suite source
802 code must be
803configured via the <tt>configure</tt> script. This script sets variables in the
804various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
805<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
806the Makefiles needed to begin building LLVM.</p>
807
808<p>The following environment variables are used by the <tt>configure</tt>
809script to configure the build system:</p>
810
811<table summary="LLVM configure script environment variables">
812 <tr><th>Variable</th><th>Purpose</th></tr>
813 <tr>
814 <td>CC</td>
815 <td>Tells <tt>configure</tt> which C compiler to use. By default,
816 <tt>configure</tt> will look for the first GCC C compiler in
817 <tt>PATH</tt>. Use this variable to override
818 <tt>configure</tt>'s default behavior.</td>
819 </tr>
820 <tr>
821 <td>CXX</td>
822 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
823 <tt>configure</tt> will look for the first GCC C++ compiler in
824 <tt>PATH</tt>. Use this variable to override
825 <tt>configure</tt>'s default behavior.</td>
826 </tr>
827</table>
828
829<p>The following options can be used to set or enable LLVM specific options:</p>
830
831<dl>
832 <dt><i>--with-llvmgccdir</i></dt>
833 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
834 The value of this option should specify the full pathname of the C/C++ Front
835 End to be used. If this option is not provided, the PATH will be searched for
836 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
837 be inferred from the path found. If the option is not given, and no llvm-gcc
838 can be found in the path then a warning will be produced by
839 <tt>configure</tt> indicating this situation. LLVM may still be built with
840 the <tt>tools-only</tt> target but attempting to build the runtime libraries
841 will fail as these libraries require llvm-gcc and llvm-g++. See
842 <a href="#installcf">Install the GCC Front End</a> for details on installing
843 the C/C++ Front End. See
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]844 <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]845 for details on building the C/C++ Front End.</dd>
846 <dt><i>--with-tclinclude</i></dt>
847 <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
848 found. Use this if you have multiple tcl installations on your machine and you
849 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
850 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
851 option, the LLVM configure script will search for the tcl 8.4 and 8.3
852 releases.
853 <br><br>
854 </dd>
855 <dt><i>--enable-optimized</i></dt>
856 <dd>
857 Enables optimized compilation by default (debugging symbols are removed
858 and GCC optimization flags are enabled). The default is to use an
859 unoptimized build (also known as a debug build).
860 <br><br>
861 </dd>
862 <dt><i>--enable-debug-runtime</i></dt>
863 <dd>
864 Enables debug symbols in the runtime libraries. The default is to strip
865 debug symbols from the runtime libraries.
866 </dd>
867 <dt><i>--enable-jit</i></dt>
868 <dd>
869 Compile the Just In Time (JIT) compiler functionality. This is not
870 available
871 on all platforms. The default is dependent on platform, so it is best
872 to explicitly enable it if you want it.
873 <br><br>
874 </dd>
875 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
876 <dd>Controls which targets will be built and linked into llc. The default
877 value for <tt>target_options</tt> is "all" which builds and links all
878 available targets. The value "host-only" can be specified to build only a
879 native compiler (no cross-compiler targets available). The "native" target is
880 selected as the target of the build host. You can also specify a comma
881 separated list of target names that you want available in llc. The target
882 names use all lower case. The current set of targets is: <br/>
883 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
884 <br><br></dd>
885 <dt><i>--enable-doxygen</i></dt>
886 <dd>Look for the doxygen program and enable construction of doxygen based
887 documentation from the source code. This is disabled by default because
888 generating the documentation can take a long time and producess 100s of
889 megabytes of output.</dd>
890 <dt><i>--with-udis86</i></dt>
891 <dd>LLVM can use external disassembler library for various purposes (now it's
892 used only for examining code produced by JIT). This option will enable usage
893 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
894 bits) disassembler library.</dd>
895</dl>
896
897<p>To configure LLVM, follow these steps:</p>
898
899<ol>
900 <li><p>Change directory into the object root directory:</p>
901
902 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
903
904 <li><p>Run the <tt>configure</tt> script located in the LLVM source
905 tree:</p>
906
907 <div class="doc_code">
908 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
909 </div></li>
910</ol>
911
912</div>
913
914<!-- ======================================================================= -->
915<div class="doc_subsection">
916 <a name="compile">Compiling the LLVM Suite Source Code</a>
917</div>
918
919<div class="doc_text">
920
921<p>Once you have configured LLVM, you can build it. There are three types of
922builds:</p>
923
924<dl>
925 <dt>Debug Builds
926 <dd>
927 These builds are the default when one types <tt>gmake</tt> (unless the
928 <tt>--enable-optimized</tt> option was used during configuration). The
929 build system will compile the tools and libraries with debugging
930 information.
931 <br><br>
932
933 <dt>Release (Optimized) Builds
934 <dd>
935 These builds are enabled with the <tt>--enable-optimized</tt> option to
936 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
937 <tt>gmake</tt> command line. For these builds, the build system will
938 compile the tools and libraries with GCC optimizations enabled and strip
939 debugging information from the libraries and executables it generates.
940 <br><br>
941
942 <dt>Profile Builds
943 <dd>
944 These builds are for use with profiling. They compile profiling
945 information into the code for use with programs like <tt>gprof</tt>.
946 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
947 on the <tt>gmake</tt> command line.
948</dl>
949
950<p>Once you have LLVM configured, you can build it by entering the
951<i>OBJ_ROOT</i> directory and issuing the following command:</p>
952
953<div class="doc_code"><pre>% gmake</pre></div>
954
955<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
956are using a version of GCC that is known not to compile LLVM.</p>
957
958<p>
959If you have multiple processors in your machine, you may wish to use some of
960the parallel build options provided by GNU Make. For example, you could use the
961command:</p>
962
963<div class="doc_code"><pre>% gmake -j2</pre></div>
964
965<p>There are several special targets which are useful when working with the LLVM
966source code:</p>
967
968<dl>
969 <dt><tt>gmake clean</tt>
970 <dd>
971 Removes all files generated by the build. This includes object files,
972 generated C/C++ files, libraries, and executables.
973 <br><br>
974
975 <dt><tt>gmake dist-clean</tt>
976 <dd>
977 Removes everything that <tt>gmake clean</tt> does, but also removes files
978 generated by <tt>configure</tt>. It attempts to return the source tree to the
979 original state in which it was shipped.
980 <br><br>
981
982 <dt><tt>gmake install</tt>
983 <dd>
984 Installs LLVM header files, libraries, tools, and documentation in a
985 hierarchy
986 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
987 defaults to <tt>/usr/local</tt>.
988 <br><br>
989
990 <dt><tt>gmake -C runtime install-bytecode</tt>
991 <dd>
992 Assuming you built LLVM into $OBJDIR, when this command is run, it will
993 install bitcode libraries into the GCC front end's bitcode library
994 directory. If you need to update your bitcode libraries,
995 this is the target to use once you've built them.
996 <br><br>
997</dl>
998
999<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
1000details on these <tt>make</tt> targets and descriptions of other targets
1001available.</p>
1002
1003<p>It is also possible to override default values from <tt>configure</tt> by
1004declaring variables on the command line. The following are some examples:</p>
1005
1006<dl>
1007 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1008 <dd>
1009 Perform a Release (Optimized) build.
1010 <br><br>
1011
1012 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1013 <dd>
1014 Perform a Release (Optimized) build without assertions enabled.
1015 <br><br>
1016
1017 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1018 <dd>
1019 Perform a Profiling build.
1020 <br><br>
1021
1022 <dt><tt>gmake VERBOSE=1</tt>
1023 <dd>
1024 Print what <tt>gmake</tt> is doing on standard output.
1025 <br><br>
1026
1027 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1028 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1029 the standard output. This also implies <tt>VERBOSE=1</tt>.
1030 <br><br></dd>
1031</dl>
1032
1033<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1034it and any subdirectories that it contains. Entering any directory inside the
1035LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1036that directory that is out of date.</p>
1037
1038</div>
1039
1040<!-- ======================================================================= -->
1041<div class="doc_subsection">
1042 <a name="cross-compile">Cross-Compiling LLVM</a>
1043</div>
1044
1045<div class="doc_text">
1046 <p>It is possible to cross-compile LLVM. That is, you can create LLVM
1047 executables and libraries for a platform different than the one one which you
1048 are compiling. To do this, a few additional steps are
1049 required. <sup><a href="#ccn_1">1</a></sup> To cross-compile LLVM, use
1050 these instructions:</p>
1051 <ol>
1052 <li>Configure and build LLVM as a native compiler. You will need
1053 just <tt>TableGen</tt> from that build.
1054 <ul>
1055 <li>If you have <tt>$LLVM_OBJ_ROOT=$LLVM_SRC_ROOT</tt> just execute
1056 <tt>make -C utils/TableGen</tt> after configuring.</li>
1057 <li>Otherwise you will need to monitor building process and terminate
1058 it just after <tt>TableGen</tt> was built.</li>
1059 </ul>
1060 </li>
1061 <li>Copy the TableGen binary to somewhere safe (out of your build tree).
1062 </li>
1063 <li>Configure LLVM to build with a cross-compiler. To do this, supply the
1064 configure script with <tt>--build</tt> and <tt>--host</tt> options that
1065 are different. The values of these options must be legal target triples
1066 that your GCC compiler supports.</li>
1067 <li>Put the saved <tt>TableGen</tt> executable into the
1068 into <tt>$LLVM_OBJ_ROOT/{BUILD_TYPE}/bin</tt> directory (e.g. into
1069 <tt>.../Release/bin</tt> for a Release build).</li>
1070 <li>Build LLVM as usual.</li>
1071 </ol>
1072 <p>The result of such a build will produce executables that are not executable
1073 on your build host (--build option) but can be executed on your compile host
1074 (--host option).</p>
1075 <p><b>Notes:</b></p>
1076 <div class="doc_notes">
1077 <ol>
1078 <li><a name="ccn_1">Cross-compiling</a> was tested only with Linux as
1079 build platform and Windows as host using mingw32 cross-compiler. Other
1080 combinations have not been tested.</li>
1081 </ol>
1082 </div>
1083</div>
1084
1085<!-- ======================================================================= -->
1086<div class="doc_subsection">
1087 <a name="objfiles">The Location of LLVM Object Files</a>
1088</div>
1089
1090<div class="doc_text">
1091
1092<p>The LLVM build system is capable of sharing a single LLVM source tree among
1093several LLVM builds. Hence, it is possible to build LLVM for several different
1094platforms or configurations using the same source tree.</p>
1095
1096<p>This is accomplished in the typical autoconf manner:</p>
1097
1098<ul>
1099 <li><p>Change directory to where the LLVM object files should live:</p>
1100
1101 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1102
1103 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1104 directory:</p>
1105
1106 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1107</ul>
1108
1109<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1110named after the build type:</p>
1111
1112<dl>
1113 <dt>Debug Builds
1114 <dd>
1115 <dl>
1116 <dt>Tools
1117 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1118 <dt>Libraries
1119 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1120 </dl>
1121 <br><br>
1122
1123 <dt>Release Builds
1124 <dd>
1125 <dl>
1126 <dt>Tools
1127 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1128 <dt>Libraries
1129 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1130 </dl>
1131 <br><br>
1132
1133 <dt>Profile Builds
1134 <dd>
1135 <dl>
1136 <dt>Tools
1137 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1138 <dt>Libraries
1139 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1140 </dl>
1141</dl>
1142
1143</div>
1144
1145<!-- ======================================================================= -->
1146<div class="doc_subsection">
1147 <a name="optionalconfig">Optional Configuration Items</a>
1148</div>
1149
1150<div class="doc_text">
1151
1152<p>
1153If you're running on a Linux system that supports the "<a
1154href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1155module, and you have root access on the system, you can set your system up to
1156execute LLVM bitcode files directly. To do this, use commands like this (the
1157first command may not be required if you are already using the module):</p>
1158
1159<div class="doc_code">
1160<pre>
1161$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1162$ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1163$ chmod u+x hello.bc (if needed)
1164$ ./hello.bc
1165</pre>
1166</div>
1167
1168<p>
1169This allows you to execute LLVM bitcode files directly. Thanks to Jack
1170Cummings for pointing this out!
1171</p>
1172
1173</div>
1174
1175
1176<!-- *********************************************************************** -->
1177<div class="doc_section">
1178 <a name="layout"><b>Program Layout</b></a>
1179</div>
1180<!-- *********************************************************************** -->
1181
1182<div class="doc_text">
1183
1184<p>One useful source of information about the LLVM source base is the LLVM <a
1185href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1186href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1187The following is a brief introduction to code layout:</p>
1188
1189</div>
1190
1191<!-- ======================================================================= -->
1192<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1193<div class="doc_text">
1194 <p>This directory contains some simple examples of how to use the LLVM IR and
1195 JIT.</p>
1196</div>
1197
1198<!-- ======================================================================= -->
1199<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1200<div class="doc_text">
1201
1202<p>This directory contains public header files exported from the LLVM
1203library. The three main subdirectories of this directory are:</p>
1204
1205<dl>
1206 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1207 <dd>This directory contains all of the LLVM specific header files. This
1208 directory also has subdirectories for different portions of LLVM:
1209 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1210 etc...</dd>
1211
1212 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1213 <dd>This directory contains generic support libraries that are provided with
1214 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1215 and a Command Line option processing library store their header files here.
1216 </dd>
1217
1218 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1219 <dd>This directory contains header files configured by the <tt>configure</tt>
1220 script. They wrap "standard" UNIX and C header files. Source code can
1221 include these header files which automatically take care of the conditional
1222 #includes that the <tt>configure</tt> script generates.</dd>
1223</dl>
1224</div>
1225
1226<!-- ======================================================================= -->
1227<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1228<div class="doc_text">
1229
1230<p>This directory contains most of the source files of the LLVM system. In LLVM,
1231almost all code exists in libraries, making it very easy to share code among the
1232different <a href="#tools">tools</a>.</p>
1233
1234<dl>
1235 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1236 <dd> This directory holds the core LLVM source files that implement core
1237 classes like Instruction and BasicBlock.</dd>
1238
1239 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1240 <dd>This directory holds the source code for the LLVM assembly language parser
1241 library.</dd>
1242
1243 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1244 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1245
1246 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1247 different program analyses, such as Dominator Information, Call Graphs,
1248 Induction Variables, Interval Identification, Natural Loop Identification,
1249 etc.</dd>
1250
1251 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1252 <dd> This directory contains the source code for the LLVM to LLVM program
1253 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1254 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1255 Elimination, and many others.</dd>
1256
1257 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1258 <dd> This directory contains files that describe various target architectures
1259 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1260 directory holds the X86 machine description while
1261 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1262
1263 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1264 <dd> This directory contains the major parts of the code generator: Instruction
1265 Selector, Instruction Scheduling, and Register Allocation.</dd>
1266
1267 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1268 <dd> This directory contains the source level debugger library that makes
1269 it possible to instrument LLVM programs so that a debugger could identify
1270 source code locations at which the program is executing.</dd>
1271
1272 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1273 <dd> This directory contains libraries for executing LLVM bitcode directly
1274 at runtime in both interpreted and JIT compiled fashions.</dd>
1275
1276 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1277 <dd> This directory contains the source code that corresponds to the header
1278 files located in <tt>llvm/include/Support/</tt>.</dd>
1279
1280 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1281 <dd>This directory contains the operating system abstraction layer that
1282 shields LLVM from platform-specific coding.</dd>
1283</dl>
1284
1285</div>
1286
1287<!-- ======================================================================= -->
1288<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1289<div class="doc_text">
1290 <p>This directory contains projects that are not strictly part of LLVM but are
1291 shipped with LLVM. This is also the directory where you should create your own
1292 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1293 to set up your own project. See <tt>llvm/projects/Stacker</tt> for a fully
1294 functional example of a compiler front end.</p>
1295</div>
1296
1297<!-- ======================================================================= -->
1298<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1299<div class="doc_text">
1300
1301<p>This directory contains libraries which are compiled into LLVM bitcode and
1302used when linking programs with the GCC front end. Most of these libraries are
1303skeleton versions of real libraries; for example, libc is a stripped down
1304version of glibc.</p>
1305
1306<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1307end to compile.</p>
1308
1309</div>
1310
1311<!-- ======================================================================= -->
1312<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1313<div class="doc_text">
1314 <p>This directory contains feature and regression tests and other basic sanity
1315 checks on the LLVM infrastructure. These are intended to run quickly and cover
1316 a lot of territory without being exhaustive.</p>
1317</div>
1318
1319<!-- ======================================================================= -->
1320<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1321<div class="doc_text">
1322 <p>This is not a directory in the normal llvm module; it is a separate
1323 Subversion
1324 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1325 This
1326 module contains a comprehensive correctness, performance, and benchmarking
1327 test
1328 suite for LLVM. It is a separate Subversion module because not every LLVM
1329 user is
1330 interested in downloading or building such a comprehensive test suite. For
1331 further details on this test suite, please see the
1332 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1333</div>
1334
1335<!-- ======================================================================= -->
1336<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1337<div class="doc_text">
1338
1339<p>The <b>tools</b> directory contains the executables built out of the
1340libraries above, which form the main part of the user interface. You can
1341always get help for a tool by typing <tt>tool_name --help</tt>. The
1342following is a brief introduction to the most important tools. More detailed
1343information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1344
1345<dl>
1346
1347 <dt><tt><b>bugpoint</b></tt></dt>
1348 <dd><tt>bugpoint</tt> is used to debug
1349 optimization passes or code generation backends by narrowing down the
1350 given test case to the minimum number of passes and/or instructions that
1351 still cause a problem, whether it is a crash or miscompilation. See <a
1352 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1353 on using <tt>bugpoint</tt>.</dd>
1354
1355 <dt><tt><b>llvmc</b></tt></dt>
1356 <dd>The LLVM Compiler Driver. This program can
1357 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1358 pre-processing, translation, optimization, assembly, and linking of programs
1359 all from one command line. <tt>llvmc</tt> also takes care of processing the
1360 dependent libraries found in bitcode. This reduces the need to get the
1361 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1362 note that this tool, while functional, is still experimental and not feature
1363 complete.</dd>
1364
1365 <dt><tt><b>llvm-ar</b></tt></dt>
1366 <dd>The archiver produces an archive containing
1367 the given LLVM bitcode files, optionally with an index for faster
1368 lookup.</dd>
1369
1370 <dt><tt><b>llvm-as</b></tt></dt>
1371 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1372 bitcode.</dd>
1373
1374 <dt><tt><b>llvm-dis</b></tt></dt>
1375 <dd>The disassembler transforms the LLVM bitcode to human readable
1376 LLVM assembly.</dd>
1377
1378 <dt><tt><b>llvm-ld</b></tt></dt>
1379 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1380 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1381 optimizations and allows optimization modules to be loaded and run so that
1382 language specific optimizations can be applied at link time.</dd>
1383
1384 <dt><tt><b>llvm-link</b></tt></dt>
1385 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1386 a single program.</dd>
1387
1388 <dt><tt><b>lli</b></tt></dt>
1389 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +0000[diff] [blame]1390 can directly execute LLVM bitcode (although very slowly...). For architectures
1391 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1392 will function as a Just-In-Time compiler (if the functionality was compiled
1393 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1394
1395 <dt><tt><b>llc</b></tt></dt>
1396 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1397 translates LLVM bitcode to a native code assembly file or to C code (with
1398 the -march=c option).</dd>
1399
1400 <dt><tt><b>llvm-gcc</b></tt></dt>
1401 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1402 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1403 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1404 usual machine code output. It works just like any other GCC compiler,
1405 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1406 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1407 separate Subversion module.</dd>
1408
1409 <dt><tt><b>opt</b></tt></dt>
1410 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1411 transformations (which are specified on the command line), and then outputs
1412 the resultant bitcode. The '<tt>opt --help</tt>' command is a good way to
1413 get a list of the program transformations available in LLVM.<br/>
1414 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1415 LLVM bitcode file and print out the results. It is primarily useful for
1416 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1417</dl>
1418</div>
1419
1420<!-- ======================================================================= -->
1421<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1422<div class="doc_text">
1423
1424<p>This directory contains utilities for working with LLVM source code, and some
1425of the utilities are actually required as part of the build process because they
1426are code generators for parts of LLVM infrastructure.</p>
1427
1428<dl>
1429 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1430 that finds differences between code that LLC generates and code that LLI
1431 generates. This is a useful tool if you are debugging one of them,
1432 assuming that the other generates correct output. For the full user
1433 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1434
1435 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1436 syntax-highlighting files which will work with Emacs and XEmacs editors,
1437 providing syntax highlighting support for LLVM assembly files and TableGen
1438 description files. For information on how to use the syntax files, consult
1439 the <tt>README</tt> file in that directory.<br><br>
1440
1441 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1442 and outputs all non-generated source files, which is useful if one wishes
1443 to do a lot of development across directories and does not want to
1444 individually find each file. One way to use it is to run, for example:
1445 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1446 tree.<br><br>
1447
1448 <dt><tt><b>llvmgrep</b></tt></dt>
1449 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1450 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1451 line. This is a very efficient way of searching the source base for a
1452 particular regular expression.</dd>
1453
1454 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1455 files in the current directory and then compiles and links the tool that
1456 is the first argument. For example, assuming you are in the directory
1457 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1458 simply running <tt>makellvm llc</tt> will make a build of the current
1459 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1460 causing a re-linking of LLC.<br><br>
1461
1462 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1463 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1464 cron script to generate nightly status reports of the functionality of
1465 tools, and the results can be seen by following the appropriate link on
1466 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1467
1468 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1469 the tool used to generate register descriptions, instruction set
1470 descriptions, and even assemblers from common TableGen description
1471 files.<br><br>
1472
1473 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1474 syntax-highlighting files which will work with the VIM editor, providing
1475 syntax highlighting support for LLVM assembly files and TableGen
1476 description files. For information on how to use the syntax files, consult
1477 the <tt>README</tt> file in that directory.<br><br>
1478
1479</dl>
1480
1481</div>
1482
1483<!-- ======================================================================= -->
1484<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1485<div class="doc_text">
1486 <p>This directory contains build scripts and project files for use with
1487 Visual C++. This allows developers on Windows to build LLVM without the need
1488 for Cygwin. The contents of this directory should be considered experimental
1489 at this time.
1490 </p>
1491</div>
1492<!-- *********************************************************************** -->
1493<div class="doc_section">
1494 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1495</div>
1496<!-- *********************************************************************** -->
1497
1498<div class="doc_text">
1499<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
1500so we only include instructiosn for llvm-gcc4.
1501</p>
1502
1503<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1504from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1505create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1506the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1507<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1508output.</p>
1509</div>
1510
1511<!-- ======================================================================= -->
1512<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1513
1514<div class="doc_text">
1515
1516<ol>
1517 <li><p>First, create a simple C file, name it 'hello.c':</p>
1518
1519<div class="doc_code">
1520<pre>
1521#include &lt;stdio.h&gt;
1522
1523int main() {
1524 printf("hello world\n");
1525 return 0;
1526}
1527</pre></div></li>
1528
1529 <li><p>Next, compile the C file into a native executable:</p>
1530
1531 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1532
1533 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1534 -c arguments work as usual (producing a native .s or .o file,
1535 respectively).</p></li>
1536
1537 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1538
1539 <div class="doc_code">
1540 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1541
1542 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1543 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1544 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1545 the bitcode file.</p>
1546
1547 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1548 </p></li>
1549
1550 <li><p>Run the program in both forms. To run the program, use:</p>
1551
1552 <div class="doc_code"><pre>% ./hello</pre></div>
1553
1554 <p>and</p>
1555
1556 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1557
1558 <p>The second examples shows how to invoke the LLVM JIT, <a
1559 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1560
1561 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1562 code:</p>
1563
1564<div class="doc_code">
1565<pre>llvm-dis &lt; hello.bc | less</pre>
1566</div></li>
1567
1568 <li><p>Compile the program to native assembly using the LLC code
1569 generator:</p>
1570
1571 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1572
1573 <li><p>Assemble the native assembly language file into a program:</p>
1574
1575<div class="doc_code">
1576<pre>
1577<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1578
1579<b>Others:</b> % gcc hello.s -o hello.native
1580</pre>
1581</div></li>
1582
1583 <li><p>Execute the native code program:</p>
1584
1585 <div class="doc_code"><pre>% ./hello.native</pre></div>
1586
1587 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1588 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1589 </li>
1590
1591</ol>
1592
1593</div>
1594
1595
1596<!-- *********************************************************************** -->
1597<div class="doc_section">
1598 <a name="problems">Common Problems</a>
1599</div>
1600<!-- *********************************************************************** -->
1601
1602<div class="doc_text">
1603
1604<p>If you are having problems building or using LLVM, or if you have any other
1605general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1606Asked Questions</a> page.</p>
1607
1608</div>
1609
1610<!-- *********************************************************************** -->
1611<div class="doc_section">
1612 <a name="links">Links</a>
1613</div>
1614<!-- *********************************************************************** -->
1615
1616<div class="doc_text">
1617
1618<p>This document is just an <b>introduction</b> to how to use LLVM to do
1619some simple things... there are many more interesting and complicated things
1620that you can do that aren't documented here (but we'll gladly accept a patch
1621if you want to write something up!). For more information about LLVM, check
1622out:</p>
1623
1624<ul>
1625 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1626 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1627 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1628 that Uses LLVM</a></li>
1629</ul>
1630
1631</div>
1632
1633<!-- *********************************************************************** -->
1634
1635<hr>
1636<address>
1637 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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1641
1642 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1643 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1644 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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1646</address>
1647</body>
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