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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 +000020 <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 +000023 </ol></li>
24
25 <li><a href="#starting">Getting Started with LLVM</a>
26 <ol>
Chris Lattner05300e42007-11-01 04:20:16 +000027 <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 +000037 </ol></li>
38
39 <li><a href="#layout">Program layout</a>
40 <ol>
Chris Lattner05300e42007-11-01 04:20:16 +000041 <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 +000051 </ol></li>
52
53 <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
54 <ol>
55 <li><a href="#tutorial4">Example with llvm-gcc4</a></li>
56 </ol>
57 <li><a href="#problems">Common Problems</a>
58 <li><a href="#links">Links</a>
59</ul>
60
61<div class="doc_author">
62 <p>Written by:
63 <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
64 <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
65 <a href="http://misha.brukman.net">Misha Brukman</a>,
66 <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and
67 <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>.
68 </p>
69</div>
70
71
72<!-- *********************************************************************** -->
73<div class="doc_section">
74 <a name="overview"><b>Overview</b></a>
75</div>
76<!-- *********************************************************************** -->
77
78<div class="doc_text">
79
80<p>Welcome to LLVM! In order to get started, you first need to know some
81basic information.</p>
82
83<p>First, LLVM comes in two pieces. The first piece is the LLVM suite. This
84contains all of the tools, libraries, and header files needed to use the low
85level virtual machine. It contains an assembler, disassembler, bitcode
86analyzer and bitcode optimizer. It also contains a test suite that can be
87used to test the LLVM tools and the GCC front end.</p>
88
89<p>The second piece is the GCC front end. This component provides a version of
90GCC that compiles C and C++ code into LLVM bitcode. Currently, the GCC front
91end uses the GCC parser to convert code to LLVM. Once
92compiled into LLVM bitcode, a program can be manipulated with the LLVM tools
93from the LLVM suite.</p>
94
95<p>
96There is a third, optional piece called llvm-test. It is a suite of programs
97with a testing harness that can be used to further test LLVM's functionality
98and performance.
99</p>
100
101</div>
102
103<!-- *********************************************************************** -->
104<div class="doc_section">
105 <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
106</div>
107<!-- *********************************************************************** -->
108
109<div class="doc_text">
110
111<p>Here's the short story for getting up and running quickly with LLVM:</p>
112
113<ol>
114 <li>Read the documentation.</li>
115 <li>Read the documentation.</li>
116 <li>Remember that you were warned twice about reading the documentation.</li>
Misha Brukman313db032008-12-29 19:38:58 +0000117 <li>Install the llvm-gcc-4.2 front end if you intend to compile C or C++:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000118 <ol>
119 <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li>
Misha Brukman313db032008-12-29 19:38:58 +0000120 <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf -</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000121 </li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000122 <li>Note: If the binary extension is ".bz" use bunzip2 instead of gunzip.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000123 <li>Add llvm-gcc's "bin" directory to your PATH variable.</li>
124 </ol></li>
125
126 <li>Get the LLVM Source Code
127 <ul>
128 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
129 <ol>
130 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
131 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
132 </ol></li>
133
134 </ul></li>
135
136 <li><b>[Optional]</b> Get the Test Suite Source Code
137 <ul>
138 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
139 <ol>
140 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
141 <li><tt>cd llvm/projects</tt>
142 <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
143 </ol></li>
144
145 </ul></li>
146
147
148 <li>Configure the LLVM Build Environment
149 <ol>
150 <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
151 <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br>
152 Some common options:
153
154 <ul>
155 <li><tt>--prefix=<i>directory</i></tt>
156 <p>Specify for <i>directory</i> the full pathname of where you
157 want the LLVM tools and libraries to be installed (default
158 <tt>/usr/local</tt>).</p></li>
159 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
160 <p>Optionally, specify for <i>directory</i> the full pathname of the
161 C/C++ front end installation to use with this LLVM configuration. If
Duncan Sandscff3d042009-04-18 12:40:19 +0000162 not specified, the PATH will be searched. This is only needed if you
163 want to run the testsuite or do some special kinds of LLVM builds.</p></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000164 <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>
Chris Lattner6abf6762009-07-22 04:21:40 +0000219 <td>AuroraUX</td>
220 <td>x86<sup><a href="#pf_1">1</a></sup></td>
221 <td>GCC</td>
Chris Lattnera8f23072009-07-21 22:47:03 +0000222</tr>
223<tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000224 <td>Linux</td>
225 <td>x86<sup><a href="#pf_1">1</a></sup></td>
226 <td>GCC</td>
227</tr>
228<tr>
Edward O'Callaghan82a57db2009-08-04 05:24:28 +0000229 <td>Linux</td>
230 <td>amd64</td>
231 <td>GCC</td>
232</tr>
233<tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000234 <td>Solaris</td>
235 <td>V9 (Ultrasparc)</td>
236 <td>GCC</td>
237</tr>
238<tr>
239 <td>FreeBSD</td>
240 <td>x86<sup><a href="#pf_1">1</a></sup></td>
241 <td>GCC</td>
242</tr>
243<tr>
244 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
245 <td>PowerPC</td>
246 <td>GCC</td>
247</tr>
248<tr>
Scott Michel6de83ff2008-03-18 23:13:26 +0000249 <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 +0000250 <td>x86</td>
251 <td>GCC</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000252</tr>
253<tr>
254 <td>Cygwin/Win32</td>
255 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a></sup></td>
256 <td>GCC 3.4.X, binutils 2.15</td>
257</tr>
258<tr>
259 <td>MinGW/Win32</td>
Anton Korobeynikovbad20c32009-08-06 12:54:58 +0000260 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,
261 <a href="#pf_8">8</a>, <a href="#pf_10">10</a></sup></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000262 <td>GCC 3.4.X, binutils 2.15</td>
263</tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000264</table>
265
266<p>LLVM has partial support for the following platforms:</p>
267
268<table summary="LLVM partial platform support">
269<tr>
270 <th>OS</th>
271 <th>Arch</th>
272 <th>Compilers</th>
273</tr>
274<tr>
275 <td>Windows</td>
276 <td>x86<sup><a href="#pf_1">1</a></sup></td>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000277 <td>Visual Studio 2005 SP1 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000278<tr>
279 <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
280 <td>PowerPC</td>
281 <td>GCC</td>
282</tr>
283<tr>
284 <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
285 <td>PowerPC</td>
286 <td>GCC</td>
287</tr>
288
289<tr>
290 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
291 <td>Alpha</td>
292 <td>GCC</td>
293</tr>
294<tr>
295 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
296 <td>Itanium (IA-64)</td>
297 <td>GCC</td>
298</tr>
299<tr>
300 <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
301 <td>Itanium (IA-64)</td>
302 <td>HP aCC</td>
303</tr>
304</table>
305
306<p><b>Notes:</b></p>
307
308<div class="doc_notes">
309<ol>
310<li><a name="pf_1">Code generation supported for Pentium processors and
311up</a></li>
312<li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
313<li><a name="pf_3">No native code generation</a></li>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000314<li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000315<li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
Chris Lattner789ce3a2009-01-02 07:10:51 +0000316<li><a name="pf_6">The port is done using the MSYS shell.</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000317<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
318<li><a name="pf_8">Binutils</a> up to post-2.17 has bug in bfd/cofflink.c
319 preventing LLVM from building correctly. Several workarounds have been
320 introduced into LLVM build system, but the bug can occur anytime in the
321 future. We highly recommend that you rebuild your current binutils with the
322 patch from <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=2659">
323 Binutils bugzilla</a>, if it wasn't already applied.</li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000324<li><a name="pf_9">XCode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip
Scott Michel6de83ff2008-03-18 23:13:26 +0000325 internal LLVM assert messages when compiled for Release at optimization
Chris Lattnerfdae8682008-11-09 17:19:14 +0000326 levels greater than 0 (i.e., <i>"-O1"</i> and higher).
327 Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
Scott Michel6de83ff2008-03-18 23:13:26 +0000328 if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
Anton Korobeynikovbad20c32009-08-06 12:54:58 +0000329<li><a name="pf_10">For MSYS/MinGW on Windows, be sure to install the MSYS
330 version of the perl package, and be sure it appears in your path
331 before any Windows-based versions such as Strawberry Perl and
332 ActivePerl, as these have Windows-specifics that will cause the
333 build to fail.</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000334</ol>
335</div>
336
337<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
338mode, depending on the system (it is so large because of all the debugging
339information and the fact that the libraries are statically linked into multiple
Chris Lattner15aeb9a2009-04-25 22:08:52 +0000340tools). If you do not need many of the tools and you are space-conscious, you
341can pass <tt>ONLY_TOOLS="tools you need"</tt> to make. The Release build
342requires considerably less space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000343
344<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
345guaranteed to do so. If compilation is successful, the LLVM utilities should be
346able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
347generation should work as well, although the generated native code may not work
348on your platform.</p>
349
350<p>The GCC front end is not very portable at the moment. If you want to get it
351to work on another platform, you can download a copy of the source and <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000352href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000353
354</div>
355
356<!-- ======================================================================= -->
357<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
358<div class="doc_text">
359 <p>Compiling LLVM requires that you have several software packages
360 installed. The table below lists those required packages. The Package column
361 is the usual name for the software package that LLVM depends on. The Version
362 column provides "known to work" versions of the package. The Notes column
363 describes how LLVM uses the package and provides other details.</p>
364 <table summary="Packages required to compile LLVM">
365 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
366
367 <tr>
368 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
369 <td>3.79, 3.79.1</td>
370 <td>Makefile/build processor</td>
371 </tr>
372
373 <tr>
374 <td><a href="http://gcc.gnu.org">GCC</a></td>
375 <td>3.4.2</td>
376 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
377 </tr>
378
379 <tr>
380 <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
381 <td>4.5</td>
382 <td>For building the CFE</td>
383 </tr>
384
385 <tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000386 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
387 <td>&ge;1.3</td>
388 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
389 </tr>
390
391 <tr>
392 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
393 <td>1.4.2</td>
394 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
395 </tr>
396
397 <tr>
398 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
399 <td>8.3, 8.4</td>
400 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
401 </tr>
402
403 <tr>
404 <td><a href="http://expect.nist.gov/">expect</a></td>
405 <td>5.38.0</td>
406 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
407 </tr>
408
409 <tr>
410 <td><a href="http://www.perl.com/download.csp">perl</a></td>
411 <td>&ge;5.6.0</td>
412 <td>Nightly tester, utilities</td>
413 </tr>
414
415 <tr>
416 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
417 <td>1.4</td>
418 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
419 </tr>
420
421 <tr>
422 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
423 <td>2.59</td>
424 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
425 </tr>
426
427 <tr>
428 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
429 <td>1.9.2</td>
430 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
431 </tr>
432
433 <tr>
434 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
435 <td>1.5.10</td>
436 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
437 </tr>
438
439 </table>
440
441 <p><b>Notes:</b></p>
442 <div class="doc_notes">
443 <ol>
444 <li><a name="sf1">Only the C and C++ languages are needed so there's no
445 need to build the other languages for LLVM's purposes.</a> See
446 <a href="#brokengcc">below</a> for specific version info.</li>
447 <li><a name="sf2">You only need Subversion if you intend to build from the
448 latest LLVM sources. If you're working from a release distribution, you
449 don't need Subversion.</a></li>
450 <li><a name="sf3">Only needed if you want to run the automated test
451 suite in the <tt>llvm/test</tt> directory.</a></li>
452 <li><a name="sf4">If you want to make changes to the configure scripts,
453 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
454 or higher). You will also need automake (1.9.2). We only use aclocal
455 from that package.</a></li>
456 </ol>
457 </div>
458
459 <p>Additionally, your compilation host is expected to have the usual
460 plethora of Unix utilities. Specifically:</p>
461 <ul>
462 <li><b>ar</b> - archive library builder</li>
463 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
464 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
465 <li><b>chmod</b> - change permissions on a file</li>
466 <li><b>cat</b> - output concatenation utility</li>
467 <li><b>cp</b> - copy files</li>
468 <li><b>date</b> - print the current date/time </li>
469 <li><b>echo</b> - print to standard output</li>
470 <li><b>egrep</b> - extended regular expression search utility</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000471 <li><b>find</b> - find files/dirs in a file system</li>
472 <li><b>grep</b> - regular expression search utility</li>
473 <li><b>gzip*</b> - gzip command for distribution generation</li>
474 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
475 <li><b>install</b> - install directories/files </li>
476 <li><b>mkdir</b> - create a directory</li>
477 <li><b>mv</b> - move (rename) files</li>
478 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
479 <li><b>rm</b> - remove (delete) files and directories</li>
480 <li><b>sed</b> - stream editor for transforming output</li>
481 <li><b>sh</b> - Bourne shell for make build scripts</li>
482 <li><b>tar</b> - tape archive for distribution generation</li>
483 <li><b>test</b> - test things in file system</li>
484 <li><b>unzip*</b> - unzip command for distribution checking</li>
485 <li><b>zip*</b> - zip command for distribution generation</li>
486 </ul>
487</div>
488
489<!-- ======================================================================= -->
490<div class="doc_subsection">
491 <a name="brokengcc">Broken versions of GCC and other tools</a>
492</div>
493
494<div class="doc_text">
495
496<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
497bugs in the compiler. In particular, several versions of GCC crash when trying
498to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
499successfully with them (however, see important notes below). Other versions
500of GCC will probably work as well. GCC versions listed
501here are known to not work. If you are using one of these versions, please try
502to upgrade your GCC to something more recent. If you run into a problem with a
503version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
504us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
505of GCC you are using.
506</p>
507
508<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
509problems in the STL that effectively prevent it from compiling LLVM.
510</p>
511
Chris Lattner76bb5302008-02-13 17:50:24 +0000512<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
513a bogus template error. This was fixed in later GCCs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000514
515<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
516href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
517the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
518
519<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 +0000520 Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000521 to a newer version</a> if possible.</p>
522<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
523 possibly others) does not compile LLVM correctly (it appears that exception
524 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
525 to a newer version of GCC.</p>
526<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
527 code generator, causing an infinite loop in the llvm-gcc build when built
528 with optimizations enabled (i.e. a release build).</p>
529<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
530 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
531 correctly compiles LLVM at -O2. A work around is to build release LLVM
532 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
533<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
534 miscompiles portions of LLVM</a>.</p>
Chris Lattner05300e42007-11-01 04:20:16 +0000535<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
536 when building with optimizations enabled. It appears to work with
537 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
538 build.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000539<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
540 miscompile LLVM.</p>
541<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
542 default with ENABLE_OPTIMIZED=1. To work around this, build with
543 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
544<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
545 compiling some files. At the time of this writing, GCC mainline (4.2)
546 did not share the problem.</p>
547<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
548 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
549 code. LLVM will appear to mostly work but will be buggy, e.g. failing
550 portions of its testsuite.</p>
551<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
552platforms compiling md5.c gets a mangled constant.</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000553<p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
554to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
555about symbols remaining in the table on destruction.</p>
Nuno Lopesfc375a62008-12-10 16:11:10 +0000556<p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms
Nuno Lopesc36ac042008-12-10 16:01:22 +0000557as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
Anton Korobeynikov30403a02009-05-04 10:24:46 +0000558<p><b>Cygwin GCC 4.3.2 20080827 (beta) 2</b>:
559 Users <a href="http://llvm.org/PR4145">reported</a> various problems related
560 with link errors when using this GCC version.</p>
Chris Lattner5d834332009-09-10 16:25:02 +0000561<p><b>Debian GCC 4.3.2 on X86</b>: Crashes building some files in LLVM 2.6.</p>
Nick Lewyckyadb7b152009-07-17 06:32:10 +0000562<p><b>GCC 4.3.3 (Debian 4.3.3-10) on ARM</b>: Miscompiles parts of LLVM 2.6
563when optimizations are turned on. The symptom is an infinite loop in
Chris Lattner5d834332009-09-10 16:25:02 +0000564FoldingSetImpl::RemoveNode while running the code generator.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000565<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
566long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
567defined in a discarded section. You can safely ignore these messages as they are
568erroneous and the linkage is correct. These messages disappear using ld
5692.17.</p>
570
571<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
572href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
573causes huge link times (minutes instead of seconds) when building LLVM. We
574recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
575
Nick Lewycky87da07c2009-03-03 05:41:16 +0000576<p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained
Nick Lewycky829108e2009-02-25 06:29:47 +0000577<a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a>
578which causes intermittent failures when building LLVM with position independent
Nick Lewycky87da07c2009-03-03 05:41:16 +0000579code. The symptom is an error about cyclic dependencies. We recommend
580upgrading to a newer version of Gold.</p>
Nick Lewycky829108e2009-02-25 06:29:47 +0000581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000582</div>
583
584
585
586<!-- *********************************************************************** -->
587<div class="doc_section">
588 <a name="starting"><b>Getting Started with LLVM</b></a>
589</div>
590<!-- *********************************************************************** -->
591
592<div class="doc_text">
593
594<p>The remainder of this guide is meant to get you up and running with
595LLVM and to give you some basic information about the LLVM environment.</p>
596
597<p>The later sections of this guide describe the <a
598href="#layout">general layout</a> of the the LLVM source tree, a <a
599href="#tutorial">simple example</a> using the LLVM tool chain, and <a
600href="#links">links</a> to find more information about LLVM or to get
601help via e-mail.</p>
602</div>
603
604<!-- ======================================================================= -->
605<div class="doc_subsection">
606 <a name="terminology">Terminology and Notation</a>
607</div>
608
609<div class="doc_text">
610
611<p>Throughout this manual, the following names are used to denote paths
612specific to the local system and working environment. <i>These are not
613environment variables you need to set but just strings used in the rest
614of this document below</i>. In any of the examples below, simply replace
615each of these names with the appropriate pathname on your local system.
616All these paths are absolute:</p>
617
618<dl>
619 <dt>SRC_ROOT
620 <dd>
621 This is the top level directory of the LLVM source tree.
622 <br><br>
623
624 <dt>OBJ_ROOT
625 <dd>
626 This is the top level directory of the LLVM object tree (i.e. the
627 tree where object files and compiled programs will be placed. It
628 can be the same as SRC_ROOT).
629 <br><br>
630
631 <dt>LLVMGCCDIR
632 <dd>
633 This is where the LLVM GCC Front End is installed.
634 <p>
635 For the pre-built GCC front end binaries, the LLVMGCCDIR is
636 <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
637</dl>
638
639</div>
640
641<!-- ======================================================================= -->
642<div class="doc_subsection">
643 <a name="environment">Setting Up Your Environment</a>
644</div>
645
646<div class="doc_text">
647
648<p>
649In order to compile and use LLVM, you may need to set some environment
650variables.
651
652<dl>
653 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
654 <dd>[Optional] This environment variable helps LLVM linking tools find the
655 locations of your bitcode libraries. It is provided only as a
656 convenience since you can specify the paths using the -L options of the
657 tools and the C/C++ front-end will automatically use the bitcode files
658 installed in its
659 <tt>lib</tt> directory.</dd>
660</dl>
661
662</div>
663
664<!-- ======================================================================= -->
665<div class="doc_subsection">
666 <a name="unpack">Unpacking the LLVM Archives</a>
667</div>
668
669<div class="doc_text">
670
671<p>
672If you have the LLVM distribution, you will need to unpack it before you
673can begin to compile it. LLVM is distributed as a set of two files: the LLVM
674suite and the LLVM GCC front end compiled for your platform. There is an
675additional test suite that is optional. Each file is a TAR archive that is
676compressed with the gzip program.
677</p>
678
679<p>The files are as follows, with <em>x.y</em> marking the version number:
680<dl>
681 <dt><tt>llvm-x.y.tar.gz</tt></dt>
Misha Brukman5c1cc642008-12-11 18:23:24 +0000682 <dd>Source release for the LLVM libraries and tools.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000683
684 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
685 <dd>Source release for the LLVM test suite.</dd>
686
Misha Brukman313db032008-12-29 19:38:58 +0000687 <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt>
688 <dd>Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root
Misha Brukman5c1cc642008-12-11 18:23:24 +0000689 directory for build instructions.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000690
Misha Brukman313db032008-12-29 19:38:58 +0000691 <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt>
692 <dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000693
694</dl>
695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000696</div>
697
698<!-- ======================================================================= -->
699<div class="doc_subsection">
700 <a name="checkout">Checkout LLVM from Subversion</a>
701</div>
702
703<div class="doc_text">
704
705<p>If you have access to our Subversion repository, you can get a fresh copy of
Chris Lattner3d55fb92009-04-25 22:24:49 +0000706the entire source code. All you need to do is check it out from Subversion as
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000707follows:</p>
708
709<ul>
710 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
711 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
712 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
713 llvm</tt></li>
714</ul>
715
716
717<p>This will create an '<tt>llvm</tt>' directory in the current
718directory and fully populate it with the LLVM source code, Makefiles,
719test directories, and local copies of documentation files.</p>
720
721<p>If you want to get a specific release (as opposed to the most recent
722revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
723'<tt>trunk</tt>'). The following releases are located in the following
Misha Brukman8e73a472008-12-17 16:27:23 +0000724subdirectories of the '<tt>tags</tt>' directory:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000725
726<ul>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000727<li>Release 2.5: <b>RELEASE_25</b></li>
Misha Brukman8e73a472008-12-17 16:27:23 +0000728<li>Release 2.4: <b>RELEASE_24</b></li>
Tanya Lattner9eb3be52008-06-09 06:02:09 +0000729<li>Release 2.3: <b>RELEASE_23</b></li>
Tanya Lattner60030782008-02-12 02:42:55 +0000730<li>Release 2.2: <b>RELEASE_22</b></li>
Tanya Lattner2fad5b02007-09-28 22:50:54 +0000731<li>Release 2.1: <b>RELEASE_21</b></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000732<li>Release 2.0: <b>RELEASE_20</b></li>
733<li>Release 1.9: <b>RELEASE_19</b></li>
734<li>Release 1.8: <b>RELEASE_18</b></li>
735<li>Release 1.7: <b>RELEASE_17</b></li>
736<li>Release 1.6: <b>RELEASE_16</b></li>
737<li>Release 1.5: <b>RELEASE_15</b></li>
738<li>Release 1.4: <b>RELEASE_14</b></li>
739<li>Release 1.3: <b>RELEASE_13</b></li>
740<li>Release 1.2: <b>RELEASE_12</b></li>
741<li>Release 1.1: <b>RELEASE_11</b></li>
742<li>Release 1.0: <b>RELEASE_1</b></li>
743</ul>
744
745<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
746you get it from the Subversion repository:</p>
747
748<div class="doc_code">
749<pre>
750% cd llvm/projects
751% svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
752</pre>
753</div>
754
755<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
756configured by the LLVM configure script as well as automatically updated when
757you run <tt>svn update</tt>.</p>
758
759<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 +0000760and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000761instructions</a> to successfully get and build the LLVM GCC front-end.</p>
762
763</div>
764
765<!-- ======================================================================= -->
766<div class="doc_subsection">
767 <a name="installcf">Install the GCC Front End</a>
768</div>
769
770<div class="doc_text">
771
772<p>Before configuring and compiling the LLVM suite, you can optionally extract the
773LLVM GCC front end from the binary distribution. It is used for running the
774llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000775<a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000776main LLVM repository.</p>
777
778<p>To install the GCC front end, do the following:</p>
779
780<ol>
781 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
Misha Brukman313db032008-12-29 19:38:58 +0000782 <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000783 -</tt></li>
784</ol>
785
786<p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
787llvm-g++ to some directory in your path. When you configure LLVM, it will
788automatically detect llvm-gcc's presence (if it is in your path) enabling its
789use in llvm-test. Note that you can always build or install llvm-gcc at any
790pointer after building the main LLVM repository: just reconfigure llvm and
791llvm-test will pick it up.
792</p>
793
794<p>The binary versions of the GCC front end may not suit all of your needs. For
795example, the binary distribution may include an old version of a system header
796file, not "fix" a header file that needs to be fixed for GCC, or it may be
797linked with libraries not available on your system.</p>
798
799<p>In cases like these, you may want to try <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000800href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000801much easier now than it was in the past.</p>
802
803</div>
804
805<!-- ======================================================================= -->
806<div class="doc_subsection">
807 <a name="config">Local LLVM Configuration</a>
808</div>
809
810<div class="doc_text">
811
812 <p>Once checked out from the Subversion repository, the LLVM suite source
813 code must be
814configured via the <tt>configure</tt> script. This script sets variables in the
815various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
816<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
817the Makefiles needed to begin building LLVM.</p>
818
819<p>The following environment variables are used by the <tt>configure</tt>
820script to configure the build system:</p>
821
822<table summary="LLVM configure script environment variables">
823 <tr><th>Variable</th><th>Purpose</th></tr>
824 <tr>
825 <td>CC</td>
826 <td>Tells <tt>configure</tt> which C compiler to use. By default,
827 <tt>configure</tt> will look for the first GCC C compiler in
828 <tt>PATH</tt>. Use this variable to override
829 <tt>configure</tt>'s default behavior.</td>
830 </tr>
831 <tr>
832 <td>CXX</td>
833 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
834 <tt>configure</tt> will look for the first GCC C++ compiler in
835 <tt>PATH</tt>. Use this variable to override
836 <tt>configure</tt>'s default behavior.</td>
837 </tr>
838</table>
839
840<p>The following options can be used to set or enable LLVM specific options:</p>
841
842<dl>
843 <dt><i>--with-llvmgccdir</i></dt>
844 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
845 The value of this option should specify the full pathname of the C/C++ Front
846 End to be used. If this option is not provided, the PATH will be searched for
847 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
848 be inferred from the path found. If the option is not given, and no llvm-gcc
849 can be found in the path then a warning will be produced by
850 <tt>configure</tt> indicating this situation. LLVM may still be built with
851 the <tt>tools-only</tt> target but attempting to build the runtime libraries
852 will fail as these libraries require llvm-gcc and llvm-g++. See
853 <a href="#installcf">Install the GCC Front End</a> for details on installing
854 the C/C++ Front End. See
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000855 <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000856 for details on building the C/C++ Front End.</dd>
857 <dt><i>--with-tclinclude</i></dt>
858 <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
859 found. Use this if you have multiple tcl installations on your machine and you
860 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
861 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
862 option, the LLVM configure script will search for the tcl 8.4 and 8.3
863 releases.
864 <br><br>
865 </dd>
866 <dt><i>--enable-optimized</i></dt>
867 <dd>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000868 Enables optimized compilation (debugging symbols are removed
869 and GCC optimization flags are enabled). Note that this is the default
870 setting if you are using the LLVM distribution. The default behavior
871 of an Subversion checkout is to use an unoptimized build (also known as a
872 debug build).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000873 <br><br>
874 </dd>
875 <dt><i>--enable-debug-runtime</i></dt>
876 <dd>
877 Enables debug symbols in the runtime libraries. The default is to strip
878 debug symbols from the runtime libraries.
879 </dd>
880 <dt><i>--enable-jit</i></dt>
881 <dd>
882 Compile the Just In Time (JIT) compiler functionality. This is not
883 available
884 on all platforms. The default is dependent on platform, so it is best
885 to explicitly enable it if you want it.
886 <br><br>
887 </dd>
888 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
889 <dd>Controls which targets will be built and linked into llc. The default
890 value for <tt>target_options</tt> is "all" which builds and links all
891 available targets. The value "host-only" can be specified to build only a
892 native compiler (no cross-compiler targets available). The "native" target is
893 selected as the target of the build host. You can also specify a comma
894 separated list of target names that you want available in llc. The target
Misha Brukman5c1cc642008-12-11 18:23:24 +0000895 names use all lower case. The current set of targets is: <br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000896 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
897 <br><br></dd>
898 <dt><i>--enable-doxygen</i></dt>
899 <dd>Look for the doxygen program and enable construction of doxygen based
900 documentation from the source code. This is disabled by default because
901 generating the documentation can take a long time and producess 100s of
902 megabytes of output.</dd>
903 <dt><i>--with-udis86</i></dt>
904 <dd>LLVM can use external disassembler library for various purposes (now it's
905 used only for examining code produced by JIT). This option will enable usage
906 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
907 bits) disassembler library.</dd>
908</dl>
909
910<p>To configure LLVM, follow these steps:</p>
911
912<ol>
913 <li><p>Change directory into the object root directory:</p>
914
915 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
916
917 <li><p>Run the <tt>configure</tt> script located in the LLVM source
918 tree:</p>
919
920 <div class="doc_code">
921 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
922 </div></li>
923</ol>
924
925</div>
926
927<!-- ======================================================================= -->
928<div class="doc_subsection">
929 <a name="compile">Compiling the LLVM Suite Source Code</a>
930</div>
931
932<div class="doc_text">
933
934<p>Once you have configured LLVM, you can build it. There are three types of
935builds:</p>
936
937<dl>
938 <dt>Debug Builds
939 <dd>
Chris Lattner3d55fb92009-04-25 22:24:49 +0000940 These builds are the default when one is using an Subversion checkout and
941 types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was
942 used during configuration). The build system will compile the tools and
943 libraries with debugging information. To get a Debug Build using the
944 LLVM distribution the <tt>--disable-optimized</tt> option must be passed
945 to <tt>configure</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000946 <br><br>
947
948 <dt>Release (Optimized) Builds
949 <dd>
950 These builds are enabled with the <tt>--enable-optimized</tt> option to
951 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
952 <tt>gmake</tt> command line. For these builds, the build system will
953 compile the tools and libraries with GCC optimizations enabled and strip
954 debugging information from the libraries and executables it generates.
Chris Lattner3d55fb92009-04-25 22:24:49 +0000955 Note that Release Builds are default when using an LLVM distribution.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000956 <br><br>
957
958 <dt>Profile Builds
959 <dd>
960 These builds are for use with profiling. They compile profiling
961 information into the code for use with programs like <tt>gprof</tt>.
962 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
963 on the <tt>gmake</tt> command line.
964</dl>
965
966<p>Once you have LLVM configured, you can build it by entering the
967<i>OBJ_ROOT</i> directory and issuing the following command:</p>
968
969<div class="doc_code"><pre>% gmake</pre></div>
970
971<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
972are using a version of GCC that is known not to compile LLVM.</p>
973
974<p>
975If you have multiple processors in your machine, you may wish to use some of
976the parallel build options provided by GNU Make. For example, you could use the
977command:</p>
978
979<div class="doc_code"><pre>% gmake -j2</pre></div>
980
981<p>There are several special targets which are useful when working with the LLVM
982source code:</p>
983
984<dl>
985 <dt><tt>gmake clean</tt>
986 <dd>
987 Removes all files generated by the build. This includes object files,
988 generated C/C++ files, libraries, and executables.
989 <br><br>
990
991 <dt><tt>gmake dist-clean</tt>
992 <dd>
993 Removes everything that <tt>gmake clean</tt> does, but also removes files
994 generated by <tt>configure</tt>. It attempts to return the source tree to the
995 original state in which it was shipped.
996 <br><br>
997
998 <dt><tt>gmake install</tt>
999 <dd>
1000 Installs LLVM header files, libraries, tools, and documentation in a
1001 hierarchy
1002 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
1003 defaults to <tt>/usr/local</tt>.
1004 <br><br>
1005
1006 <dt><tt>gmake -C runtime install-bytecode</tt>
1007 <dd>
1008 Assuming you built LLVM into $OBJDIR, when this command is run, it will
1009 install bitcode libraries into the GCC front end's bitcode library
1010 directory. If you need to update your bitcode libraries,
1011 this is the target to use once you've built them.
1012 <br><br>
1013</dl>
1014
1015<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
1016details on these <tt>make</tt> targets and descriptions of other targets
1017available.</p>
1018
1019<p>It is also possible to override default values from <tt>configure</tt> by
1020declaring variables on the command line. The following are some examples:</p>
1021
1022<dl>
1023 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1024 <dd>
1025 Perform a Release (Optimized) build.
1026 <br><br>
1027
1028 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1029 <dd>
1030 Perform a Release (Optimized) build without assertions enabled.
1031 <br><br>
Chris Lattner3d55fb92009-04-25 22:24:49 +00001032
1033 <dt><tt>gmake ENABLE_OPTIMIZED=0</tt>
1034 <dd>
1035 Perform a Debug build.
1036 <br><br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001037
1038 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1039 <dd>
1040 Perform a Profiling build.
1041 <br><br>
1042
1043 <dt><tt>gmake VERBOSE=1</tt>
1044 <dd>
1045 Print what <tt>gmake</tt> is doing on standard output.
1046 <br><br>
1047
1048 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1049 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1050 the standard output. This also implies <tt>VERBOSE=1</tt>.
1051 <br><br></dd>
1052</dl>
1053
1054<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1055it and any subdirectories that it contains. Entering any directory inside the
1056LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1057that directory that is out of date.</p>
1058
1059</div>
1060
1061<!-- ======================================================================= -->
1062<div class="doc_subsection">
1063 <a name="cross-compile">Cross-Compiling LLVM</a>
1064</div>
1065
1066<div class="doc_text">
Jim Grosbachc8c74362009-04-17 17:25:16 +00001067 <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
1068 executables and libraries to be hosted on a platform different from the
1069 platform where they are build (a Canadian Cross build). To configure a
1070 cross-compile, supply the configure script with <tt>--build</tt> and
1071 <tt>--host</tt> options that are different. The values of these options must
1072 be legal target triples that your GCC compiler supports.</p>
1073
1074 <p>The result of such a build is executables that are not runnable on
1075 on the build host (--build option) but can be executed on the compile host
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001076 (--host option).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001077</div>
1078
1079<!-- ======================================================================= -->
1080<div class="doc_subsection">
1081 <a name="objfiles">The Location of LLVM Object Files</a>
1082</div>
1083
1084<div class="doc_text">
1085
1086<p>The LLVM build system is capable of sharing a single LLVM source tree among
1087several LLVM builds. Hence, it is possible to build LLVM for several different
1088platforms or configurations using the same source tree.</p>
1089
1090<p>This is accomplished in the typical autoconf manner:</p>
1091
1092<ul>
1093 <li><p>Change directory to where the LLVM object files should live:</p>
1094
1095 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1096
1097 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1098 directory:</p>
1099
1100 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1101</ul>
1102
1103<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1104named after the build type:</p>
1105
1106<dl>
1107 <dt>Debug Builds
1108 <dd>
1109 <dl>
1110 <dt>Tools
1111 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1112 <dt>Libraries
1113 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1114 </dl>
1115 <br><br>
1116
1117 <dt>Release Builds
1118 <dd>
1119 <dl>
1120 <dt>Tools
1121 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1122 <dt>Libraries
1123 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1124 </dl>
1125 <br><br>
1126
1127 <dt>Profile Builds
1128 <dd>
1129 <dl>
1130 <dt>Tools
1131 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1132 <dt>Libraries
1133 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1134 </dl>
1135</dl>
1136
1137</div>
1138
1139<!-- ======================================================================= -->
1140<div class="doc_subsection">
1141 <a name="optionalconfig">Optional Configuration Items</a>
1142</div>
1143
1144<div class="doc_text">
1145
1146<p>
1147If you're running on a Linux system that supports the "<a
1148href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1149module, and you have root access on the system, you can set your system up to
1150execute LLVM bitcode files directly. To do this, use commands like this (the
1151first command may not be required if you are already using the module):</p>
1152
1153<div class="doc_code">
1154<pre>
1155$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1156$ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1157$ chmod u+x hello.bc (if needed)
1158$ ./hello.bc
1159</pre>
1160</div>
1161
1162<p>
1163This allows you to execute LLVM bitcode files directly. Thanks to Jack
1164Cummings for pointing this out!
1165</p>
1166
1167</div>
1168
1169
1170<!-- *********************************************************************** -->
1171<div class="doc_section">
1172 <a name="layout"><b>Program Layout</b></a>
1173</div>
1174<!-- *********************************************************************** -->
1175
1176<div class="doc_text">
1177
1178<p>One useful source of information about the LLVM source base is the LLVM <a
1179href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1180href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1181The following is a brief introduction to code layout:</p>
1182
1183</div>
1184
1185<!-- ======================================================================= -->
1186<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1187<div class="doc_text">
1188 <p>This directory contains some simple examples of how to use the LLVM IR and
1189 JIT.</p>
1190</div>
1191
1192<!-- ======================================================================= -->
1193<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1194<div class="doc_text">
1195
1196<p>This directory contains public header files exported from the LLVM
1197library. The three main subdirectories of this directory are:</p>
1198
1199<dl>
1200 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1201 <dd>This directory contains all of the LLVM specific header files. This
1202 directory also has subdirectories for different portions of LLVM:
1203 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1204 etc...</dd>
1205
1206 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1207 <dd>This directory contains generic support libraries that are provided with
1208 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1209 and a Command Line option processing library store their header files here.
1210 </dd>
1211
1212 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1213 <dd>This directory contains header files configured by the <tt>configure</tt>
1214 script. They wrap "standard" UNIX and C header files. Source code can
1215 include these header files which automatically take care of the conditional
1216 #includes that the <tt>configure</tt> script generates.</dd>
1217</dl>
1218</div>
1219
1220<!-- ======================================================================= -->
1221<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1222<div class="doc_text">
1223
1224<p>This directory contains most of the source files of the LLVM system. In LLVM,
1225almost all code exists in libraries, making it very easy to share code among the
1226different <a href="#tools">tools</a>.</p>
1227
1228<dl>
1229 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1230 <dd> This directory holds the core LLVM source files that implement core
1231 classes like Instruction and BasicBlock.</dd>
1232
1233 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1234 <dd>This directory holds the source code for the LLVM assembly language parser
1235 library.</dd>
1236
1237 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1238 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1239
1240 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1241 different program analyses, such as Dominator Information, Call Graphs,
1242 Induction Variables, Interval Identification, Natural Loop Identification,
1243 etc.</dd>
1244
1245 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1246 <dd> This directory contains the source code for the LLVM to LLVM program
1247 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1248 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1249 Elimination, and many others.</dd>
1250
1251 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1252 <dd> This directory contains files that describe various target architectures
1253 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1254 directory holds the X86 machine description while
1255 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1256
1257 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1258 <dd> This directory contains the major parts of the code generator: Instruction
1259 Selector, Instruction Scheduling, and Register Allocation.</dd>
1260
1261 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1262 <dd> This directory contains the source level debugger library that makes
1263 it possible to instrument LLVM programs so that a debugger could identify
1264 source code locations at which the program is executing.</dd>
1265
1266 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1267 <dd> This directory contains libraries for executing LLVM bitcode directly
1268 at runtime in both interpreted and JIT compiled fashions.</dd>
1269
1270 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1271 <dd> This directory contains the source code that corresponds to the header
1272 files located in <tt>llvm/include/Support/</tt>.</dd>
1273
1274 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1275 <dd>This directory contains the operating system abstraction layer that
1276 shields LLVM from platform-specific coding.</dd>
1277</dl>
1278
1279</div>
1280
1281<!-- ======================================================================= -->
1282<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1283<div class="doc_text">
1284 <p>This directory contains projects that are not strictly part of LLVM but are
1285 shipped with LLVM. This is also the directory where you should create your own
1286 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
Chris Lattneraf1df782008-08-11 06:13:31 +00001287 to set up your own project.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001288</div>
1289
1290<!-- ======================================================================= -->
1291<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1292<div class="doc_text">
1293
1294<p>This directory contains libraries which are compiled into LLVM bitcode and
1295used when linking programs with the GCC front end. Most of these libraries are
1296skeleton versions of real libraries; for example, libc is a stripped down
1297version of glibc.</p>
1298
1299<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1300end to compile.</p>
1301
1302</div>
1303
1304<!-- ======================================================================= -->
1305<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1306<div class="doc_text">
1307 <p>This directory contains feature and regression tests and other basic sanity
1308 checks on the LLVM infrastructure. These are intended to run quickly and cover
1309 a lot of territory without being exhaustive.</p>
1310</div>
1311
1312<!-- ======================================================================= -->
1313<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1314<div class="doc_text">
1315 <p>This is not a directory in the normal llvm module; it is a separate
1316 Subversion
1317 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1318 This
1319 module contains a comprehensive correctness, performance, and benchmarking
1320 test
1321 suite for LLVM. It is a separate Subversion module because not every LLVM
1322 user is
1323 interested in downloading or building such a comprehensive test suite. For
1324 further details on this test suite, please see the
1325 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1326</div>
1327
1328<!-- ======================================================================= -->
1329<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1330<div class="doc_text">
1331
1332<p>The <b>tools</b> directory contains the executables built out of the
1333libraries above, which form the main part of the user interface. You can
1334always get help for a tool by typing <tt>tool_name --help</tt>. The
1335following is a brief introduction to the most important tools. More detailed
1336information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1337
1338<dl>
1339
1340 <dt><tt><b>bugpoint</b></tt></dt>
1341 <dd><tt>bugpoint</tt> is used to debug
1342 optimization passes or code generation backends by narrowing down the
1343 given test case to the minimum number of passes and/or instructions that
1344 still cause a problem, whether it is a crash or miscompilation. See <a
1345 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1346 on using <tt>bugpoint</tt>.</dd>
1347
1348 <dt><tt><b>llvmc</b></tt></dt>
1349 <dd>The LLVM Compiler Driver. This program can
1350 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1351 pre-processing, translation, optimization, assembly, and linking of programs
1352 all from one command line. <tt>llvmc</tt> also takes care of processing the
1353 dependent libraries found in bitcode. This reduces the need to get the
1354 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1355 note that this tool, while functional, is still experimental and not feature
1356 complete.</dd>
1357
1358 <dt><tt><b>llvm-ar</b></tt></dt>
1359 <dd>The archiver produces an archive containing
1360 the given LLVM bitcode files, optionally with an index for faster
1361 lookup.</dd>
1362
1363 <dt><tt><b>llvm-as</b></tt></dt>
1364 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1365 bitcode.</dd>
1366
1367 <dt><tt><b>llvm-dis</b></tt></dt>
1368 <dd>The disassembler transforms the LLVM bitcode to human readable
1369 LLVM assembly.</dd>
1370
1371 <dt><tt><b>llvm-ld</b></tt></dt>
1372 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1373 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1374 optimizations and allows optimization modules to be loaded and run so that
1375 language specific optimizations can be applied at link time.</dd>
1376
1377 <dt><tt><b>llvm-link</b></tt></dt>
1378 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1379 a single program.</dd>
1380
1381 <dt><tt><b>lli</b></tt></dt>
1382 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +00001383 can directly execute LLVM bitcode (although very slowly...). For architectures
1384 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1385 will function as a Just-In-Time compiler (if the functionality was compiled
1386 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001387
1388 <dt><tt><b>llc</b></tt></dt>
1389 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1390 translates LLVM bitcode to a native code assembly file or to C code (with
1391 the -march=c option).</dd>
1392
1393 <dt><tt><b>llvm-gcc</b></tt></dt>
1394 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1395 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1396 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1397 usual machine code output. It works just like any other GCC compiler,
1398 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1399 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1400 separate Subversion module.</dd>
1401
1402 <dt><tt><b>opt</b></tt></dt>
1403 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1404 transformations (which are specified on the command line), and then outputs
1405 the resultant bitcode. The '<tt>opt --help</tt>' command is a good way to
Misha Brukman5c1cc642008-12-11 18:23:24 +00001406 get a list of the program transformations available in LLVM.<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001407 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1408 LLVM bitcode file and print out the results. It is primarily useful for
1409 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1410</dl>
1411</div>
1412
1413<!-- ======================================================================= -->
1414<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1415<div class="doc_text">
1416
1417<p>This directory contains utilities for working with LLVM source code, and some
1418of the utilities are actually required as part of the build process because they
1419are code generators for parts of LLVM infrastructure.</p>
1420
1421<dl>
1422 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1423 that finds differences between code that LLC generates and code that LLI
1424 generates. This is a useful tool if you are debugging one of them,
1425 assuming that the other generates correct output. For the full user
1426 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1427
1428 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1429 syntax-highlighting files which will work with Emacs and XEmacs editors,
1430 providing syntax highlighting support for LLVM assembly files and TableGen
1431 description files. For information on how to use the syntax files, consult
1432 the <tt>README</tt> file in that directory.<br><br>
1433
1434 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1435 and outputs all non-generated source files, which is useful if one wishes
1436 to do a lot of development across directories and does not want to
1437 individually find each file. One way to use it is to run, for example:
1438 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1439 tree.<br><br>
1440
1441 <dt><tt><b>llvmgrep</b></tt></dt>
1442 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1443 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1444 line. This is a very efficient way of searching the source base for a
1445 particular regular expression.</dd>
1446
1447 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1448 files in the current directory and then compiles and links the tool that
1449 is the first argument. For example, assuming you are in the directory
1450 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1451 simply running <tt>makellvm llc</tt> will make a build of the current
1452 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1453 causing a re-linking of LLC.<br><br>
1454
1455 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1456 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1457 cron script to generate nightly status reports of the functionality of
1458 tools, and the results can be seen by following the appropriate link on
1459 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1460
1461 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1462 the tool used to generate register descriptions, instruction set
1463 descriptions, and even assemblers from common TableGen description
1464 files.<br><br>
1465
1466 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1467 syntax-highlighting files which will work with the VIM editor, providing
1468 syntax highlighting support for LLVM assembly files and TableGen
1469 description files. For information on how to use the syntax files, consult
1470 the <tt>README</tt> file in that directory.<br><br>
1471
1472</dl>
1473
1474</div>
1475
1476<!-- ======================================================================= -->
1477<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1478<div class="doc_text">
1479 <p>This directory contains build scripts and project files for use with
1480 Visual C++. This allows developers on Windows to build LLVM without the need
1481 for Cygwin. The contents of this directory should be considered experimental
1482 at this time.
1483 </p>
1484</div>
1485<!-- *********************************************************************** -->
1486<div class="doc_section">
1487 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1488</div>
1489<!-- *********************************************************************** -->
1490
1491<div class="doc_text">
1492<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
Chris Lattnere6099642009-04-10 15:38:51 +00001493so we only include instructions for llvm-gcc4.
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001494</p>
1495
1496<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1497from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1498create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1499the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1500<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1501output.</p>
1502</div>
1503
1504<!-- ======================================================================= -->
1505<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1506
1507<div class="doc_text">
1508
1509<ol>
1510 <li><p>First, create a simple C file, name it 'hello.c':</p>
1511
1512<div class="doc_code">
1513<pre>
1514#include &lt;stdio.h&gt;
1515
1516int main() {
1517 printf("hello world\n");
1518 return 0;
1519}
1520</pre></div></li>
1521
1522 <li><p>Next, compile the C file into a native executable:</p>
1523
1524 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1525
1526 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1527 -c arguments work as usual (producing a native .s or .o file,
1528 respectively).</p></li>
1529
1530 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1531
1532 <div class="doc_code">
1533 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1534
1535 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1536 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1537 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1538 the bitcode file.</p>
1539
1540 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1541 </p></li>
1542
1543 <li><p>Run the program in both forms. To run the program, use:</p>
1544
1545 <div class="doc_code"><pre>% ./hello</pre></div>
1546
1547 <p>and</p>
1548
1549 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1550
1551 <p>The second examples shows how to invoke the LLVM JIT, <a
1552 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1553
1554 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1555 code:</p>
1556
1557<div class="doc_code">
1558<pre>llvm-dis &lt; hello.bc | less</pre>
1559</div></li>
1560
1561 <li><p>Compile the program to native assembly using the LLC code
1562 generator:</p>
1563
1564 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1565
1566 <li><p>Assemble the native assembly language file into a program:</p>
1567
1568<div class="doc_code">
1569<pre>
1570<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1571
1572<b>Others:</b> % gcc hello.s -o hello.native
1573</pre>
1574</div></li>
1575
1576 <li><p>Execute the native code program:</p>
1577
1578 <div class="doc_code"><pre>% ./hello.native</pre></div>
1579
1580 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1581 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1582 </li>
1583
1584</ol>
1585
1586</div>
1587
1588
1589<!-- *********************************************************************** -->
1590<div class="doc_section">
1591 <a name="problems">Common Problems</a>
1592</div>
1593<!-- *********************************************************************** -->
1594
1595<div class="doc_text">
1596
1597<p>If you are having problems building or using LLVM, or if you have any other
1598general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1599Asked Questions</a> page.</p>
1600
1601</div>
1602
1603<!-- *********************************************************************** -->
1604<div class="doc_section">
1605 <a name="links">Links</a>
1606</div>
1607<!-- *********************************************************************** -->
1608
1609<div class="doc_text">
1610
Bill Wendling08f49b92008-07-22 01:10:25 +00001611<p>This document is just an <b>introduction</b> on how to use LLVM to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001612some simple things... there are many more interesting and complicated things
1613that you can do that aren't documented here (but we'll gladly accept a patch
1614if you want to write something up!). For more information about LLVM, check
1615out:</p>
1616
1617<ul>
1618 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1619 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1620 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1621 that Uses LLVM</a></li>
1622</ul>
1623
1624</div>
1625
1626<!-- *********************************************************************** -->
1627
1628<hr>
1629<address>
1630 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +00001634
1635 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1636 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1637 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
1638 Last modified: $Date$
1639</address>
1640</body>
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