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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 +0000[diff] [blame]20 <li><a href="#hardware">Hardware</a></li>
21 <li><a href="#software">Software</a></li>
22 <li><a href="#brokengcc">Broken versions of GCC and other tools</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]23 </ol></li>
24
25 <li><a href="#starting">Getting Started with LLVM</a>
26 <ol>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]27 <li><a href="#terminology">Terminology and Notation</a></li>
28 <li><a href="#environment">Setting Up Your Environment</a></li>
29 <li><a href="#unpack">Unpacking the LLVM Archives</a></li>
30 <li><a href="#checkout">Checkout LLVM from Subversion</a></li>
31 <li><a href="#installcf">Install the GCC Front End</a></li>
32 <li><a href="#config">Local LLVM Configuration</a></li>
33 <li><a href="#compile">Compiling the LLVM Suite Source Code</a></li>
34 <li><a href="#cross-compile">Cross-Compiling LLVM</a></li>
35 <li><a href="#objfiles">The Location of LLVM Object Files</a></li>
36 <li><a href="#optionalconfig">Optional Configuration Items</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]37 </ol></li>
38
39 <li><a href="#layout">Program layout</a>
40 <ol>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]41 <li><a href="#examples"><tt>llvm/examples</tt></a></li>
42 <li><a href="#include"><tt>llvm/include</tt></a></li>
43 <li><a href="#lib"><tt>llvm/lib</tt></a></li>
44 <li><a href="#projects"><tt>llvm/projects</tt></a></li>
45 <li><a href="#runtime"><tt>llvm/runtime</tt></a></li>
46 <li><a href="#test"><tt>llvm/test</tt></a></li>
47 <li><a href="#llvmtest"><tt>llvm-test</tt></a></li>
48 <li><a href="#tools"><tt>llvm/tools</tt></a></li>
49 <li><a href="#utils"><tt>llvm/utils</tt></a></li>
50 <li><a href="#win32"><tt>llvm/win32</tt></a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]51 </ol></li>
52
53 <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
54 <ol>
55 <li><a href="#tutorial4">Example with llvm-gcc4</a></li>
56 </ol>
57 <li><a href="#problems">Common Problems</a>
58 <li><a href="#links">Links</a>
59</ul>
60
61<div class="doc_author">
62 <p>Written by:
63 <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
64 <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
65 <a href="http://misha.brukman.net">Misha Brukman</a>,
66 <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and
67 <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>.
68 </p>
69</div>
70
71
72<!-- *********************************************************************** -->
73<div class="doc_section">
74 <a name="overview"><b>Overview</b></a>
75</div>
76<!-- *********************************************************************** -->
77
78<div class="doc_text">
79
80<p>Welcome to LLVM! In order to get started, you first need to know some
81basic information.</p>
82
83<p>First, LLVM comes in two pieces. The first piece is the LLVM suite. This
84contains all of the tools, libraries, and header files needed to use the low
85level virtual machine. It contains an assembler, disassembler, bitcode
86analyzer and bitcode optimizer. It also contains a test suite that can be
87used to test the LLVM tools and the GCC front end.</p>
88
89<p>The second piece is the GCC front end. This component provides a version of
90GCC that compiles C and C++ code into LLVM bitcode. Currently, the GCC front
91end uses the GCC parser to convert code to LLVM. Once
92compiled into LLVM bitcode, a program can be manipulated with the LLVM tools
93from the LLVM suite.</p>
94
95<p>
96There is a third, optional piece called llvm-test. It is a suite of programs
97with a testing harness that can be used to further test LLVM's functionality
98and performance.
99</p>
100
101</div>
102
103<!-- *********************************************************************** -->
104<div class="doc_section">
105 <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
106</div>
107<!-- *********************************************************************** -->
108
109<div class="doc_text">
110
111<p>Here's the short story for getting up and running quickly with LLVM:</p>
112
113<ol>
114 <li>Read the documentation.</li>
115 <li>Read the documentation.</li>
116 <li>Remember that you were warned twice about reading the documentation.</li>
Tanya Lattnerf3ff76b2008-04-07 18:32:25 +0000[diff] [blame]117 <li>Install the llvm-gcc4.2 front end if you intend to compile C or C++:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]118 <ol>
119 <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li>
120 <li><tt>gunzip --stdout llvm-gcc.<i>platform</i>.tar.gz | tar -xvf -</tt>
121 </li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]122 <li>Note: If the binary extension is ".bz" use bunzip2 instead of gunzip.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li>Add llvm-gcc's "bin" directory to your PATH variable.</li>
124 </ol></li>
125
126 <li>Get the LLVM Source Code
127 <ul>
128 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
129 <ol>
130 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
131 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
132 </ol></li>
133
134 </ul></li>
135
136 <li><b>[Optional]</b> Get the Test Suite Source Code
137 <ul>
138 <li>With the distributed files (or use <a href="#checkout">SVN</a>):
139 <ol>
140 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
141 <li><tt>cd llvm/projects</tt>
142 <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
143 </ol></li>
144
145 </ul></li>
146
147
148 <li>Configure the LLVM Build Environment
149 <ol>
150 <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
151 <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br>
152 Some common options:
153
154 <ul>
155 <li><tt>--prefix=<i>directory</i></tt>
156 <p>Specify for <i>directory</i> the full pathname of where you
157 want the LLVM tools and libraries to be installed (default
158 <tt>/usr/local</tt>).</p></li>
159 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
160 <p>Optionally, specify for <i>directory</i> the full pathname of the
161 C/C++ front end installation to use with this LLVM configuration. If
162 not specified, the PATH will be searched.</p></li>
163 <li><tt>--enable-spec2000=<i>directory</i></tt>
164 <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
165 benchmarks should be available in
166 <tt><i>directory</i></tt>.</p></li>
167 </ul>
168 </ol></li>
169
170 <li>Build the LLVM Suite:
171 <ol>
172 <li><tt>gmake -k |&amp; tee gnumake.out
173 &nbsp;&nbsp;&nbsp;# this is csh or tcsh syntax</tt></li>
174 <li>If you get an "internal compiler error (ICE)" or test failures, see
175 <a href="#brokengcc">below</a>.</li>
176 </ol>
177
178</ol>
179
180<p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
181detailed information on configuring and compiling LLVM. See <a
182href="#environment">Setting Up Your Environment</a> for tips that simplify
183working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
184Layout</a> to learn about the layout of the source code tree.</p>
185
186</div>
187
188<!-- *********************************************************************** -->
189<div class="doc_section">
190 <a name="requirements"><b>Requirements</b></a>
191</div>
192<!-- *********************************************************************** -->
193
194<div class="doc_text">
195
196<p>Before you begin to use the LLVM system, review the requirements given below.
197This may save you some trouble by knowing ahead of time what hardware and
198software you will need.</p>
199
200</div>
201
202<!-- ======================================================================= -->
203<div class="doc_subsection">
204 <a name="hardware"><b>Hardware</b></a>
205</div>
206
207<div class="doc_text">
208
209<p>LLVM is known to work on the following platforms:</p>
210
211<table cellpadding="3" summary="Known LLVM platforms">
212<tr>
213 <th>OS</th>
214 <th>Arch</th>
215 <th>Compilers</th>
216</tr>
217<tr>
218 <td>Linux</td>
219 <td>x86<sup><a href="#pf_1">1</a></sup></td>
220 <td>GCC</td>
221</tr>
222<tr>
223 <td>Solaris</td>
224 <td>V9 (Ultrasparc)</td>
225 <td>GCC</td>
226</tr>
227<tr>
228 <td>FreeBSD</td>
229 <td>x86<sup><a href="#pf_1">1</a></sup></td>
230 <td>GCC</td>
231</tr>
232<tr>
233 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
234 <td>PowerPC</td>
235 <td>GCC</td>
236</tr>
237<tr>
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]238 <td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]239 <td>x86</td>
240 <td>GCC</td>
241
242</tr>
243<tr>
244 <td>Cygwin/Win32</td>
245 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a></sup></td>
246 <td>GCC 3.4.X, binutils 2.15</td>
247</tr>
248<tr>
249 <td>MinGW/Win32</td>
250 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,<a href="#pf_8">8</a></sup></td>
251 <td>GCC 3.4.X, binutils 2.15</td>
252</tr>
253<tr>
254 <td>Linux</td>
Dan Gohman99fc2442008-11-13 19:07:07 +0000[diff] [blame]255 <td>amd64</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]256 <td>GCC</td>
257</tr>
258</table>
259
260<p>LLVM has partial support for the following platforms:</p>
261
262<table summary="LLVM partial platform support">
263<tr>
264 <th>OS</th>
265 <th>Arch</th>
266 <th>Compilers</th>
267</tr>
268<tr>
269 <td>Windows</td>
270 <td>x86<sup><a href="#pf_1">1</a></sup></td>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]271 <td>Visual Studio 2005 SP1 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]272<tr>
273 <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
274 <td>PowerPC</td>
275 <td>GCC</td>
276</tr>
277<tr>
278 <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
279 <td>PowerPC</td>
280 <td>GCC</td>
281</tr>
282
283<tr>
284 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
285 <td>Alpha</td>
286 <td>GCC</td>
287</tr>
288<tr>
289 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
290 <td>Itanium (IA-64)</td>
291 <td>GCC</td>
292</tr>
293<tr>
294 <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
295 <td>Itanium (IA-64)</td>
296 <td>HP aCC</td>
297</tr>
298</table>
299
300<p><b>Notes:</b></p>
301
302<div class="doc_notes">
303<ol>
304<li><a name="pf_1">Code generation supported for Pentium processors and
305up</a></li>
306<li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
307<li><a name="pf_3">No native code generation</a></li>
Nick Lewycky18b90af2008-12-08 00:45:02 +0000[diff] [blame]308<li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]309<li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
310<li><a name="pf_6">The port is done using the MSYS shell.</a>
311<a href="http://www.mingw.org/MinGWiki/">Download</a> and install
312bison (excl. M4.exe) and flex in that order. Build binutils-2.15 from source,
313if necessary. Bison &amp; flex can be also grabbed from GNUWin32 sf.net
314project.</li>
315<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
316<li><a name="pf_8">Binutils</a> up to post-2.17 has bug in bfd/cofflink.c
317 preventing LLVM from building correctly. Several workarounds have been
318 introduced into LLVM build system, but the bug can occur anytime in the
319 future. We highly recommend that you rebuild your current binutils with the
320 patch from <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=2659">
321 Binutils bugzilla</a>, if it wasn't already applied.</li>
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]322<li><a name="pf_9">XCode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]323 internal LLVM assert messages when compiled for Release at optimization
Chris Lattnerfdae8682008-11-09 17:19:14 +0000[diff] [blame]324 levels greater than 0 (i.e., <i>"-O1"</i> and higher).
325 Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
Scott Michel6de83ff2008-03-18 23:13:26 +0000[diff] [blame]326 if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]327</ol>
328</div>
329
330<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
331mode, depending on the system (it is so large because of all the debugging
332information and the fact that the libraries are statically linked into multiple
333tools). If you do not need many of the tools and you are space-conscious,
334you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
335build requires considerably less space.</p>
336
337<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
338guaranteed to do so. If compilation is successful, the LLVM utilities should be
339able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
340generation should work as well, although the generated native code may not work
341on your platform.</p>
342
343<p>The GCC front end is not very portable at the moment. If you want to get it
344to work on another platform, you can download a copy of the source and <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]345href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346
347</div>
348
349<!-- ======================================================================= -->
350<div class="doc_subsection"><a name="software"><b>Software</b></a></div>
351<div class="doc_text">
352 <p>Compiling LLVM requires that you have several software packages
353 installed. The table below lists those required packages. The Package column
354 is the usual name for the software package that LLVM depends on. The Version
355 column provides "known to work" versions of the package. The Notes column
356 describes how LLVM uses the package and provides other details.</p>
357 <table summary="Packages required to compile LLVM">
358 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
359
360 <tr>
361 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
362 <td>3.79, 3.79.1</td>
363 <td>Makefile/build processor</td>
364 </tr>
365
366 <tr>
367 <td><a href="http://gcc.gnu.org">GCC</a></td>
368 <td>3.4.2</td>
369 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
370 </tr>
371
372 <tr>
373 <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
374 <td>4.5</td>
375 <td>For building the CFE</td>
376 </tr>
377
378 <tr>
379 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
380 <td>2.5.4</td>
381 <td>LEX compiler</td>
382 </tr>
383
384 <tr>
385 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
386 <td>1.28, 1.35, 1.75, 1.875d, 2.0, or 2.1<br>(not 1.85 or 1.875)</td>
387 <td>YACC compiler</td>
388 </tr>
389
390 <tr>
391 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
392 <td>&ge;1.3</td>
393 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
394 </tr>
395
396 <tr>
397 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
398 <td>1.4.2</td>
399 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
400 </tr>
401
402 <tr>
403 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
404 <td>8.3, 8.4</td>
405 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
406 </tr>
407
408 <tr>
409 <td><a href="http://expect.nist.gov/">expect</a></td>
410 <td>5.38.0</td>
411 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
412 </tr>
413
414 <tr>
415 <td><a href="http://www.perl.com/download.csp">perl</a></td>
416 <td>&ge;5.6.0</td>
417 <td>Nightly tester, utilities</td>
418 </tr>
419
420 <tr>
421 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
422 <td>1.4</td>
423 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
424 </tr>
425
426 <tr>
427 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
428 <td>2.59</td>
429 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
430 </tr>
431
432 <tr>
433 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
434 <td>1.9.2</td>
435 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
436 </tr>
437
438 <tr>
439 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
440 <td>1.5.10</td>
441 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
442 </tr>
443
444 </table>
445
446 <p><b>Notes:</b></p>
447 <div class="doc_notes">
448 <ol>
449 <li><a name="sf1">Only the C and C++ languages are needed so there's no
450 need to build the other languages for LLVM's purposes.</a> See
451 <a href="#brokengcc">below</a> for specific version info.</li>
452 <li><a name="sf2">You only need Subversion if you intend to build from the
453 latest LLVM sources. If you're working from a release distribution, you
454 don't need Subversion.</a></li>
455 <li><a name="sf3">Only needed if you want to run the automated test
456 suite in the <tt>llvm/test</tt> directory.</a></li>
457 <li><a name="sf4">If you want to make changes to the configure scripts,
458 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
459 or higher). You will also need automake (1.9.2). We only use aclocal
460 from that package.</a></li>
461 </ol>
462 </div>
463
464 <p>Additionally, your compilation host is expected to have the usual
465 plethora of Unix utilities. Specifically:</p>
466 <ul>
467 <li><b>ar</b> - archive library builder</li>
468 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
469 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
470 <li><b>chmod</b> - change permissions on a file</li>
471 <li><b>cat</b> - output concatenation utility</li>
472 <li><b>cp</b> - copy files</li>
473 <li><b>date</b> - print the current date/time </li>
474 <li><b>echo</b> - print to standard output</li>
475 <li><b>egrep</b> - extended regular expression search utility</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]476 <li><b>find</b> - find files/dirs in a file system</li>
477 <li><b>grep</b> - regular expression search utility</li>
478 <li><b>gzip*</b> - gzip command for distribution generation</li>
479 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
480 <li><b>install</b> - install directories/files </li>
481 <li><b>mkdir</b> - create a directory</li>
482 <li><b>mv</b> - move (rename) files</li>
483 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
484 <li><b>rm</b> - remove (delete) files and directories</li>
485 <li><b>sed</b> - stream editor for transforming output</li>
486 <li><b>sh</b> - Bourne shell for make build scripts</li>
487 <li><b>tar</b> - tape archive for distribution generation</li>
488 <li><b>test</b> - test things in file system</li>
489 <li><b>unzip*</b> - unzip command for distribution checking</li>
490 <li><b>zip*</b> - zip command for distribution generation</li>
491 </ul>
492</div>
493
494<!-- ======================================================================= -->
495<div class="doc_subsection">
496 <a name="brokengcc">Broken versions of GCC and other tools</a>
497</div>
498
499<div class="doc_text">
500
501<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
502bugs in the compiler. In particular, several versions of GCC crash when trying
503to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
504successfully with them (however, see important notes below). Other versions
505of GCC will probably work as well. GCC versions listed
506here are known to not work. If you are using one of these versions, please try
507to upgrade your GCC to something more recent. If you run into a problem with a
508version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
509us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
510of GCC you are using.
511</p>
512
513<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
514problems in the STL that effectively prevent it from compiling LLVM.
515</p>
516
Chris Lattner76bb5302008-02-13 17:50:24 +0000[diff] [blame]517<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
518a bogus template error. This was fixed in later GCCs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]519
520<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
521href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
522the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
523
524<p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]525 Cygwin does not work. Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]526 to a newer version</a> if possible.</p>
527<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
528 possibly others) does not compile LLVM correctly (it appears that exception
529 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
530 to a newer version of GCC.</p>
531<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
532 code generator, causing an infinite loop in the llvm-gcc build when built
533 with optimizations enabled (i.e. a release build).</p>
534<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
535 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
536 correctly compiles LLVM at -O2. A work around is to build release LLVM
537 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
538<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
539 miscompiles portions of LLVM</a>.</p>
Chris Lattner05300e42007-11-01 04:20:16 +0000[diff] [blame]540<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
541 when building with optimizations enabled. It appears to work with
542 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
543 build.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]544<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
545 miscompile LLVM.</p>
546<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
547 default with ENABLE_OPTIMIZED=1. To work around this, build with
548 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
549<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
550 compiling some files. At the time of this writing, GCC mainline (4.2)
551 did not share the problem.</p>
552<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
553 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
554 code. LLVM will appear to mostly work but will be buggy, e.g. failing
555 portions of its testsuite.</p>
556<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
557platforms compiling md5.c gets a mangled constant.</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000[diff] [blame]558<p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
559to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
560about symbols remaining in the table on destruction.</p>
Nuno Lopesfc375a62008-12-10 16:11:10 +0000[diff] [blame]561<p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms
Nuno Lopesc36ac042008-12-10 16:01:22 +0000[diff] [blame]562as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
Daniel Dunbar597fdcd2008-10-11 18:40:33 +0000[diff] [blame]563
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
565long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
566defined in a discarded section. You can safely ignore these messages as they are
567erroneous and the linkage is correct. These messages disappear using ld
5682.17.</p>
569
570<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
571href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
572causes huge link times (minutes instead of seconds) when building LLVM. We
573recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
574
575</div>
576
577
578
579<!-- *********************************************************************** -->
580<div class="doc_section">
581 <a name="starting"><b>Getting Started with LLVM</b></a>
582</div>
583<!-- *********************************************************************** -->
584
585<div class="doc_text">
586
587<p>The remainder of this guide is meant to get you up and running with
588LLVM and to give you some basic information about the LLVM environment.</p>
589
590<p>The later sections of this guide describe the <a
591href="#layout">general layout</a> of the the LLVM source tree, a <a
592href="#tutorial">simple example</a> using the LLVM tool chain, and <a
593href="#links">links</a> to find more information about LLVM or to get
594help via e-mail.</p>
595</div>
596
597<!-- ======================================================================= -->
598<div class="doc_subsection">
599 <a name="terminology">Terminology and Notation</a>
600</div>
601
602<div class="doc_text">
603
604<p>Throughout this manual, the following names are used to denote paths
605specific to the local system and working environment. <i>These are not
606environment variables you need to set but just strings used in the rest
607of this document below</i>. In any of the examples below, simply replace
608each of these names with the appropriate pathname on your local system.
609All these paths are absolute:</p>
610
611<dl>
612 <dt>SRC_ROOT
613 <dd>
614 This is the top level directory of the LLVM source tree.
615 <br><br>
616
617 <dt>OBJ_ROOT
618 <dd>
619 This is the top level directory of the LLVM object tree (i.e. the
620 tree where object files and compiled programs will be placed. It
621 can be the same as SRC_ROOT).
622 <br><br>
623
624 <dt>LLVMGCCDIR
625 <dd>
626 This is where the LLVM GCC Front End is installed.
627 <p>
628 For the pre-built GCC front end binaries, the LLVMGCCDIR is
629 <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
630</dl>
631
632</div>
633
634<!-- ======================================================================= -->
635<div class="doc_subsection">
636 <a name="environment">Setting Up Your Environment</a>
637</div>
638
639<div class="doc_text">
640
641<p>
642In order to compile and use LLVM, you may need to set some environment
643variables.
644
645<dl>
646 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
647 <dd>[Optional] This environment variable helps LLVM linking tools find the
648 locations of your bitcode libraries. It is provided only as a
649 convenience since you can specify the paths using the -L options of the
650 tools and the C/C++ front-end will automatically use the bitcode files
651 installed in its
652 <tt>lib</tt> directory.</dd>
653</dl>
654
655</div>
656
657<!-- ======================================================================= -->
658<div class="doc_subsection">
659 <a name="unpack">Unpacking the LLVM Archives</a>
660</div>
661
662<div class="doc_text">
663
664<p>
665If you have the LLVM distribution, you will need to unpack it before you
666can begin to compile it. LLVM is distributed as a set of two files: the LLVM
667suite and the LLVM GCC front end compiled for your platform. There is an
668additional test suite that is optional. Each file is a TAR archive that is
669compressed with the gzip program.
670</p>
671
672<p>The files are as follows, with <em>x.y</em> marking the version number:
673<dl>
674 <dt><tt>llvm-x.y.tar.gz</tt></dt>
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]675 <dd>Source release for the LLVM libraries and tools.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]676
677 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
678 <dd>Source release for the LLVM test suite.</dd>
679
680 <dt><tt>llvm-gcc4-x.y.source.tar.gz</tt></dt>
681 <dd>Source release of the llvm-gcc4 front end. See README.LLVM in the root
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]682 directory for build instructions.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]683
684 <dt><tt>llvm-gcc4-x.y-platform.tar.gz</tt></dt>
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]685 <dd>Binary release of the llvm-gcc4 front end for a specific platform.<br></dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]686
687</dl>
688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689</div>
690
691<!-- ======================================================================= -->
692<div class="doc_subsection">
693 <a name="checkout">Checkout LLVM from Subversion</a>
694</div>
695
696<div class="doc_text">
697
698<p>If you have access to our Subversion repository, you can get a fresh copy of
699the entire source code. All you need to do is check it out from Subvresion as
700follows:</p>
701
702<ul>
703 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
704 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
705 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
706 llvm</tt></li>
707</ul>
708
709
710<p>This will create an '<tt>llvm</tt>' directory in the current
711directory and fully populate it with the LLVM source code, Makefiles,
712test directories, and local copies of documentation files.</p>
713
714<p>If you want to get a specific release (as opposed to the most recent
715revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
716'<tt>trunk</tt>'). The following releases are located in the following
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]717subdirectories of the '<tt>tags</tt>' directory:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]718
719<ul>
Misha Brukman8e73a472008-12-17 16:27:23 +0000[diff] [blame]720<li>Release 2.4: <b>RELEASE_24</b></li>
Tanya Lattner9eb3be52008-06-09 06:02:09 +0000[diff] [blame]721<li>Release 2.3: <b>RELEASE_23</b></li>
Tanya Lattner60030782008-02-12 02:42:55 +0000[diff] [blame]722<li>Release 2.2: <b>RELEASE_22</b></li>
Tanya Lattner2fad5b02007-09-28 22:50:54 +0000[diff] [blame]723<li>Release 2.1: <b>RELEASE_21</b></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]724<li>Release 2.0: <b>RELEASE_20</b></li>
725<li>Release 1.9: <b>RELEASE_19</b></li>
726<li>Release 1.8: <b>RELEASE_18</b></li>
727<li>Release 1.7: <b>RELEASE_17</b></li>
728<li>Release 1.6: <b>RELEASE_16</b></li>
729<li>Release 1.5: <b>RELEASE_15</b></li>
730<li>Release 1.4: <b>RELEASE_14</b></li>
731<li>Release 1.3: <b>RELEASE_13</b></li>
732<li>Release 1.2: <b>RELEASE_12</b></li>
733<li>Release 1.1: <b>RELEASE_11</b></li>
734<li>Release 1.0: <b>RELEASE_1</b></li>
735</ul>
736
737<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
738you get it from the Subversion repository:</p>
739
740<div class="doc_code">
741<pre>
742% cd llvm/projects
743% svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
744</pre>
745</div>
746
747<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
748configured by the LLVM configure script as well as automatically updated when
749you run <tt>svn update</tt>.</p>
750
751<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]752and build it yourself. Please follow <a href="GCCFEBuildInstrs.html">these
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]753instructions</a> to successfully get and build the LLVM GCC front-end.</p>
754
755</div>
756
757<!-- ======================================================================= -->
758<div class="doc_subsection">
759 <a name="installcf">Install the GCC Front End</a>
760</div>
761
762<div class="doc_text">
763
764<p>Before configuring and compiling the LLVM suite, you can optionally extract the
765LLVM GCC front end from the binary distribution. It is used for running the
766llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]767<a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]768main LLVM repository.</p>
769
770<p>To install the GCC front end, do the following:</p>
771
772<ol>
773 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
774 <li><tt>gunzip --stdout llvmgcc-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
775 -</tt></li>
776</ol>
777
778<p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
779llvm-g++ to some directory in your path. When you configure LLVM, it will
780automatically detect llvm-gcc's presence (if it is in your path) enabling its
781use in llvm-test. Note that you can always build or install llvm-gcc at any
782pointer after building the main LLVM repository: just reconfigure llvm and
783llvm-test will pick it up.
784</p>
785
786<p>The binary versions of the GCC front end may not suit all of your needs. For
787example, the binary distribution may include an old version of a system header
788file, not "fix" a header file that needs to be fixed for GCC, or it may be
789linked with libraries not available on your system.</p>
790
791<p>In cases like these, you may want to try <a
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]792href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]793much easier now than it was in the past.</p>
794
795</div>
796
797<!-- ======================================================================= -->
798<div class="doc_subsection">
799 <a name="config">Local LLVM Configuration</a>
800</div>
801
802<div class="doc_text">
803
804 <p>Once checked out from the Subversion repository, the LLVM suite source
805 code must be
806configured via the <tt>configure</tt> script. This script sets variables in the
807various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
808<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
809the Makefiles needed to begin building LLVM.</p>
810
811<p>The following environment variables are used by the <tt>configure</tt>
812script to configure the build system:</p>
813
814<table summary="LLVM configure script environment variables">
815 <tr><th>Variable</th><th>Purpose</th></tr>
816 <tr>
817 <td>CC</td>
818 <td>Tells <tt>configure</tt> which C compiler to use. By default,
819 <tt>configure</tt> will look for the first GCC C compiler in
820 <tt>PATH</tt>. Use this variable to override
821 <tt>configure</tt>'s default behavior.</td>
822 </tr>
823 <tr>
824 <td>CXX</td>
825 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
826 <tt>configure</tt> will look for the first GCC C++ compiler in
827 <tt>PATH</tt>. Use this variable to override
828 <tt>configure</tt>'s default behavior.</td>
829 </tr>
830</table>
831
832<p>The following options can be used to set or enable LLVM specific options:</p>
833
834<dl>
835 <dt><i>--with-llvmgccdir</i></dt>
836 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
837 The value of this option should specify the full pathname of the C/C++ Front
838 End to be used. If this option is not provided, the PATH will be searched for
839 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
840 be inferred from the path found. If the option is not given, and no llvm-gcc
841 can be found in the path then a warning will be produced by
842 <tt>configure</tt> indicating this situation. LLVM may still be built with
843 the <tt>tools-only</tt> target but attempting to build the runtime libraries
844 will fail as these libraries require llvm-gcc and llvm-g++. See
845 <a href="#installcf">Install the GCC Front End</a> for details on installing
846 the C/C++ Front End. See
Duncan Sandse38f3dc2008-02-14 17:53:22 +0000[diff] [blame]847 <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]848 for details on building the C/C++ Front End.</dd>
849 <dt><i>--with-tclinclude</i></dt>
850 <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
851 found. Use this if you have multiple tcl installations on your machine and you
852 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
853 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
854 option, the LLVM configure script will search for the tcl 8.4 and 8.3
855 releases.
856 <br><br>
857 </dd>
858 <dt><i>--enable-optimized</i></dt>
859 <dd>
860 Enables optimized compilation by default (debugging symbols are removed
861 and GCC optimization flags are enabled). The default is to use an
862 unoptimized build (also known as a debug build).
863 <br><br>
864 </dd>
865 <dt><i>--enable-debug-runtime</i></dt>
866 <dd>
867 Enables debug symbols in the runtime libraries. The default is to strip
868 debug symbols from the runtime libraries.
869 </dd>
870 <dt><i>--enable-jit</i></dt>
871 <dd>
872 Compile the Just In Time (JIT) compiler functionality. This is not
873 available
874 on all platforms. The default is dependent on platform, so it is best
875 to explicitly enable it if you want it.
876 <br><br>
877 </dd>
878 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
879 <dd>Controls which targets will be built and linked into llc. The default
880 value for <tt>target_options</tt> is "all" which builds and links all
881 available targets. The value "host-only" can be specified to build only a
882 native compiler (no cross-compiler targets available). The "native" target is
883 selected as the target of the build host. You can also specify a comma
884 separated list of target names that you want available in llc. The target
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]885 names use all lower case. The current set of targets is: <br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]886 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
887 <br><br></dd>
888 <dt><i>--enable-doxygen</i></dt>
889 <dd>Look for the doxygen program and enable construction of doxygen based
890 documentation from the source code. This is disabled by default because
891 generating the documentation can take a long time and producess 100s of
892 megabytes of output.</dd>
893 <dt><i>--with-udis86</i></dt>
894 <dd>LLVM can use external disassembler library for various purposes (now it's
895 used only for examining code produced by JIT). This option will enable usage
896 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
897 bits) disassembler library.</dd>
898</dl>
899
900<p>To configure LLVM, follow these steps:</p>
901
902<ol>
903 <li><p>Change directory into the object root directory:</p>
904
905 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
906
907 <li><p>Run the <tt>configure</tt> script located in the LLVM source
908 tree:</p>
909
910 <div class="doc_code">
911 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
912 </div></li>
913</ol>
914
915</div>
916
917<!-- ======================================================================= -->
918<div class="doc_subsection">
919 <a name="compile">Compiling the LLVM Suite Source Code</a>
920</div>
921
922<div class="doc_text">
923
924<p>Once you have configured LLVM, you can build it. There are three types of
925builds:</p>
926
927<dl>
928 <dt>Debug Builds
929 <dd>
930 These builds are the default when one types <tt>gmake</tt> (unless the
931 <tt>--enable-optimized</tt> option was used during configuration). The
932 build system will compile the tools and libraries with debugging
933 information.
934 <br><br>
935
936 <dt>Release (Optimized) Builds
937 <dd>
938 These builds are enabled with the <tt>--enable-optimized</tt> option to
939 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
940 <tt>gmake</tt> command line. For these builds, the build system will
941 compile the tools and libraries with GCC optimizations enabled and strip
942 debugging information from the libraries and executables it generates.
943 <br><br>
944
945 <dt>Profile Builds
946 <dd>
947 These builds are for use with profiling. They compile profiling
948 information into the code for use with programs like <tt>gprof</tt>.
949 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
950 on the <tt>gmake</tt> command line.
951</dl>
952
953<p>Once you have LLVM configured, you can build it by entering the
954<i>OBJ_ROOT</i> directory and issuing the following command:</p>
955
956<div class="doc_code"><pre>% gmake</pre></div>
957
958<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
959are using a version of GCC that is known not to compile LLVM.</p>
960
961<p>
962If you have multiple processors in your machine, you may wish to use some of
963the parallel build options provided by GNU Make. For example, you could use the
964command:</p>
965
966<div class="doc_code"><pre>% gmake -j2</pre></div>
967
968<p>There are several special targets which are useful when working with the LLVM
969source code:</p>
970
971<dl>
972 <dt><tt>gmake clean</tt>
973 <dd>
974 Removes all files generated by the build. This includes object files,
975 generated C/C++ files, libraries, and executables.
976 <br><br>
977
978 <dt><tt>gmake dist-clean</tt>
979 <dd>
980 Removes everything that <tt>gmake clean</tt> does, but also removes files
981 generated by <tt>configure</tt>. It attempts to return the source tree to the
982 original state in which it was shipped.
983 <br><br>
984
985 <dt><tt>gmake install</tt>
986 <dd>
987 Installs LLVM header files, libraries, tools, and documentation in a
988 hierarchy
989 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
990 defaults to <tt>/usr/local</tt>.
991 <br><br>
992
993 <dt><tt>gmake -C runtime install-bytecode</tt>
994 <dd>
995 Assuming you built LLVM into $OBJDIR, when this command is run, it will
996 install bitcode libraries into the GCC front end's bitcode library
997 directory. If you need to update your bitcode libraries,
998 this is the target to use once you've built them.
999 <br><br>
1000</dl>
1001
1002<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
1003details on these <tt>make</tt> targets and descriptions of other targets
1004available.</p>
1005
1006<p>It is also possible to override default values from <tt>configure</tt> by
1007declaring variables on the command line. The following are some examples:</p>
1008
1009<dl>
1010 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1011 <dd>
1012 Perform a Release (Optimized) build.
1013 <br><br>
1014
1015 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1016 <dd>
1017 Perform a Release (Optimized) build without assertions enabled.
1018 <br><br>
1019
1020 <dt><tt>gmake ENABLE_PROFILING=1</tt>
1021 <dd>
1022 Perform a Profiling build.
1023 <br><br>
1024
1025 <dt><tt>gmake VERBOSE=1</tt>
1026 <dd>
1027 Print what <tt>gmake</tt> is doing on standard output.
1028 <br><br>
1029
1030 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1031 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1032 the standard output. This also implies <tt>VERBOSE=1</tt>.
1033 <br><br></dd>
1034</dl>
1035
1036<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1037it and any subdirectories that it contains. Entering any directory inside the
1038LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1039that directory that is out of date.</p>
1040
1041</div>
1042
1043<!-- ======================================================================= -->
1044<div class="doc_subsection">
1045 <a name="cross-compile">Cross-Compiling LLVM</a>
1046</div>
1047
1048<div class="doc_text">
1049 <p>It is possible to cross-compile LLVM. That is, you can create LLVM
1050 executables and libraries for a platform different than the one one which you
1051 are compiling. To do this, a few additional steps are
1052 required. <sup><a href="#ccn_1">1</a></sup> To cross-compile LLVM, use
1053 these instructions:</p>
1054 <ol>
1055 <li>Configure and build LLVM as a native compiler. You will need
1056 just <tt>TableGen</tt> from that build.
1057 <ul>
1058 <li>If you have <tt>$LLVM_OBJ_ROOT=$LLVM_SRC_ROOT</tt> just execute
1059 <tt>make -C utils/TableGen</tt> after configuring.</li>
1060 <li>Otherwise you will need to monitor building process and terminate
1061 it just after <tt>TableGen</tt> was built.</li>
1062 </ul>
1063 </li>
1064 <li>Copy the TableGen binary to somewhere safe (out of your build tree).
1065 </li>
1066 <li>Configure LLVM to build with a cross-compiler. To do this, supply the
1067 configure script with <tt>--build</tt> and <tt>--host</tt> options that
1068 are different. The values of these options must be legal target triples
1069 that your GCC compiler supports.</li>
1070 <li>Put the saved <tt>TableGen</tt> executable into the
1071 into <tt>$LLVM_OBJ_ROOT/{BUILD_TYPE}/bin</tt> directory (e.g. into
1072 <tt>.../Release/bin</tt> for a Release build).</li>
1073 <li>Build LLVM as usual.</li>
1074 </ol>
1075 <p>The result of such a build will produce executables that are not executable
1076 on your build host (--build option) but can be executed on your compile host
1077 (--host option).</p>
1078 <p><b>Notes:</b></p>
1079 <div class="doc_notes">
1080 <ol>
1081 <li><a name="ccn_1">Cross-compiling</a> was tested only with Linux as
1082 build platform and Windows as host using mingw32 cross-compiler. Other
1083 combinations have not been tested.</li>
1084 </ol>
1085 </div>
1086</div>
1087
1088<!-- ======================================================================= -->
1089<div class="doc_subsection">
1090 <a name="objfiles">The Location of LLVM Object Files</a>
1091</div>
1092
1093<div class="doc_text">
1094
1095<p>The LLVM build system is capable of sharing a single LLVM source tree among
1096several LLVM builds. Hence, it is possible to build LLVM for several different
1097platforms or configurations using the same source tree.</p>
1098
1099<p>This is accomplished in the typical autoconf manner:</p>
1100
1101<ul>
1102 <li><p>Change directory to where the LLVM object files should live:</p>
1103
1104 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1105
1106 <li><p>Run the <tt>configure</tt> script found in the LLVM source
1107 directory:</p>
1108
1109 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1110</ul>
1111
1112<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1113named after the build type:</p>
1114
1115<dl>
1116 <dt>Debug Builds
1117 <dd>
1118 <dl>
1119 <dt>Tools
1120 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1121 <dt>Libraries
1122 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1123 </dl>
1124 <br><br>
1125
1126 <dt>Release Builds
1127 <dd>
1128 <dl>
1129 <dt>Tools
1130 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1131 <dt>Libraries
1132 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1133 </dl>
1134 <br><br>
1135
1136 <dt>Profile Builds
1137 <dd>
1138 <dl>
1139 <dt>Tools
1140 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1141 <dt>Libraries
1142 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1143 </dl>
1144</dl>
1145
1146</div>
1147
1148<!-- ======================================================================= -->
1149<div class="doc_subsection">
1150 <a name="optionalconfig">Optional Configuration Items</a>
1151</div>
1152
1153<div class="doc_text">
1154
1155<p>
1156If you're running on a Linux system that supports the "<a
1157href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1158module, and you have root access on the system, you can set your system up to
1159execute LLVM bitcode files directly. To do this, use commands like this (the
1160first command may not be required if you are already using the module):</p>
1161
1162<div class="doc_code">
1163<pre>
1164$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1165$ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1166$ chmod u+x hello.bc (if needed)
1167$ ./hello.bc
1168</pre>
1169</div>
1170
1171<p>
1172This allows you to execute LLVM bitcode files directly. Thanks to Jack
1173Cummings for pointing this out!
1174</p>
1175
1176</div>
1177
1178
1179<!-- *********************************************************************** -->
1180<div class="doc_section">
1181 <a name="layout"><b>Program Layout</b></a>
1182</div>
1183<!-- *********************************************************************** -->
1184
1185<div class="doc_text">
1186
1187<p>One useful source of information about the LLVM source base is the LLVM <a
1188href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1189href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1190The following is a brief introduction to code layout:</p>
1191
1192</div>
1193
1194<!-- ======================================================================= -->
1195<div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1196<div class="doc_text">
1197 <p>This directory contains some simple examples of how to use the LLVM IR and
1198 JIT.</p>
1199</div>
1200
1201<!-- ======================================================================= -->
1202<div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1203<div class="doc_text">
1204
1205<p>This directory contains public header files exported from the LLVM
1206library. The three main subdirectories of this directory are:</p>
1207
1208<dl>
1209 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1210 <dd>This directory contains all of the LLVM specific header files. This
1211 directory also has subdirectories for different portions of LLVM:
1212 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1213 etc...</dd>
1214
1215 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1216 <dd>This directory contains generic support libraries that are provided with
1217 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1218 and a Command Line option processing library store their header files here.
1219 </dd>
1220
1221 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1222 <dd>This directory contains header files configured by the <tt>configure</tt>
1223 script. They wrap "standard" UNIX and C header files. Source code can
1224 include these header files which automatically take care of the conditional
1225 #includes that the <tt>configure</tt> script generates.</dd>
1226</dl>
1227</div>
1228
1229<!-- ======================================================================= -->
1230<div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1231<div class="doc_text">
1232
1233<p>This directory contains most of the source files of the LLVM system. In LLVM,
1234almost all code exists in libraries, making it very easy to share code among the
1235different <a href="#tools">tools</a>.</p>
1236
1237<dl>
1238 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1239 <dd> This directory holds the core LLVM source files that implement core
1240 classes like Instruction and BasicBlock.</dd>
1241
1242 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1243 <dd>This directory holds the source code for the LLVM assembly language parser
1244 library.</dd>
1245
1246 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1247 <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1248
1249 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1250 different program analyses, such as Dominator Information, Call Graphs,
1251 Induction Variables, Interval Identification, Natural Loop Identification,
1252 etc.</dd>
1253
1254 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1255 <dd> This directory contains the source code for the LLVM to LLVM program
1256 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1257 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1258 Elimination, and many others.</dd>
1259
1260 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1261 <dd> This directory contains files that describe various target architectures
1262 for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
1263 directory holds the X86 machine description while
1264 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1265
1266 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1267 <dd> This directory contains the major parts of the code generator: Instruction
1268 Selector, Instruction Scheduling, and Register Allocation.</dd>
1269
1270 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1271 <dd> This directory contains the source level debugger library that makes
1272 it possible to instrument LLVM programs so that a debugger could identify
1273 source code locations at which the program is executing.</dd>
1274
1275 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1276 <dd> This directory contains libraries for executing LLVM bitcode directly
1277 at runtime in both interpreted and JIT compiled fashions.</dd>
1278
1279 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1280 <dd> This directory contains the source code that corresponds to the header
1281 files located in <tt>llvm/include/Support/</tt>.</dd>
1282
1283 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1284 <dd>This directory contains the operating system abstraction layer that
1285 shields LLVM from platform-specific coding.</dd>
1286</dl>
1287
1288</div>
1289
1290<!-- ======================================================================= -->
1291<div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1292<div class="doc_text">
1293 <p>This directory contains projects that are not strictly part of LLVM but are
1294 shipped with LLVM. This is also the directory where you should create your own
1295 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
Chris Lattneraf1df782008-08-11 06:13:31 +0000[diff] [blame]1296 to set up your own project.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1297</div>
1298
1299<!-- ======================================================================= -->
1300<div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1301<div class="doc_text">
1302
1303<p>This directory contains libraries which are compiled into LLVM bitcode and
1304used when linking programs with the GCC front end. Most of these libraries are
1305skeleton versions of real libraries; for example, libc is a stripped down
1306version of glibc.</p>
1307
1308<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1309end to compile.</p>
1310
1311</div>
1312
1313<!-- ======================================================================= -->
1314<div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1315<div class="doc_text">
1316 <p>This directory contains feature and regression tests and other basic sanity
1317 checks on the LLVM infrastructure. These are intended to run quickly and cover
1318 a lot of territory without being exhaustive.</p>
1319</div>
1320
1321<!-- ======================================================================= -->
1322<div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1323<div class="doc_text">
1324 <p>This is not a directory in the normal llvm module; it is a separate
1325 Subversion
1326 module that must be checked out (usually to <tt>projects/test-suite</tt>).
1327 This
1328 module contains a comprehensive correctness, performance, and benchmarking
1329 test
1330 suite for LLVM. It is a separate Subversion module because not every LLVM
1331 user is
1332 interested in downloading or building such a comprehensive test suite. For
1333 further details on this test suite, please see the
1334 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1335</div>
1336
1337<!-- ======================================================================= -->
1338<div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1339<div class="doc_text">
1340
1341<p>The <b>tools</b> directory contains the executables built out of the
1342libraries above, which form the main part of the user interface. You can
1343always get help for a tool by typing <tt>tool_name --help</tt>. The
1344following is a brief introduction to the most important tools. More detailed
1345information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1346
1347<dl>
1348
1349 <dt><tt><b>bugpoint</b></tt></dt>
1350 <dd><tt>bugpoint</tt> is used to debug
1351 optimization passes or code generation backends by narrowing down the
1352 given test case to the minimum number of passes and/or instructions that
1353 still cause a problem, whether it is a crash or miscompilation. See <a
1354 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1355 on using <tt>bugpoint</tt>.</dd>
1356
1357 <dt><tt><b>llvmc</b></tt></dt>
1358 <dd>The LLVM Compiler Driver. This program can
1359 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1360 pre-processing, translation, optimization, assembly, and linking of programs
1361 all from one command line. <tt>llvmc</tt> also takes care of processing the
1362 dependent libraries found in bitcode. This reduces the need to get the
1363 traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1364 note that this tool, while functional, is still experimental and not feature
1365 complete.</dd>
1366
1367 <dt><tt><b>llvm-ar</b></tt></dt>
1368 <dd>The archiver produces an archive containing
1369 the given LLVM bitcode files, optionally with an index for faster
1370 lookup.</dd>
1371
1372 <dt><tt><b>llvm-as</b></tt></dt>
1373 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1374 bitcode.</dd>
1375
1376 <dt><tt><b>llvm-dis</b></tt></dt>
1377 <dd>The disassembler transforms the LLVM bitcode to human readable
1378 LLVM assembly.</dd>
1379
1380 <dt><tt><b>llvm-ld</b></tt></dt>
1381 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1382 This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1383 optimizations and allows optimization modules to be loaded and run so that
1384 language specific optimizations can be applied at link time.</dd>
1385
1386 <dt><tt><b>llvm-link</b></tt></dt>
1387 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1388 a single program.</dd>
1389
1390 <dt><tt><b>lli</b></tt></dt>
1391 <dd><tt>lli</tt> is the LLVM interpreter, which
Nick Lewycky32dc2a12007-12-03 01:58:01 +0000[diff] [blame]1392 can directly execute LLVM bitcode (although very slowly...). For architectures
1393 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1394 will function as a Just-In-Time compiler (if the functionality was compiled
1395 in), and will execute the code <i>much</i> faster than the interpreter.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1396
1397 <dt><tt><b>llc</b></tt></dt>
1398 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1399 translates LLVM bitcode to a native code assembly file or to C code (with
1400 the -march=c option).</dd>
1401
1402 <dt><tt><b>llvm-gcc</b></tt></dt>
1403 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1404 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1405 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1406 usual machine code output. It works just like any other GCC compiler,
1407 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1408 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1409 separate Subversion module.</dd>
1410
1411 <dt><tt><b>opt</b></tt></dt>
1412 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1413 transformations (which are specified on the command line), and then outputs
1414 the resultant bitcode. The '<tt>opt --help</tt>' command is a good way to
Misha Brukman5c1cc642008-12-11 18:23:24 +0000[diff] [blame]1415 get a list of the program transformations available in LLVM.<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1416 <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1417 LLVM bitcode file and print out the results. It is primarily useful for
1418 debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1419</dl>
1420</div>
1421
1422<!-- ======================================================================= -->
1423<div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1424<div class="doc_text">
1425
1426<p>This directory contains utilities for working with LLVM source code, and some
1427of the utilities are actually required as part of the build process because they
1428are code generators for parts of LLVM infrastructure.</p>
1429
1430<dl>
1431 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1432 that finds differences between code that LLC generates and code that LLI
1433 generates. This is a useful tool if you are debugging one of them,
1434 assuming that the other generates correct output. For the full user
1435 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1436
1437 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1438 syntax-highlighting files which will work with Emacs and XEmacs editors,
1439 providing syntax highlighting support for LLVM assembly files and TableGen
1440 description files. For information on how to use the syntax files, consult
1441 the <tt>README</tt> file in that directory.<br><br>
1442
1443 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1444 and outputs all non-generated source files, which is useful if one wishes
1445 to do a lot of development across directories and does not want to
1446 individually find each file. One way to use it is to run, for example:
1447 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1448 tree.<br><br>
1449
1450 <dt><tt><b>llvmgrep</b></tt></dt>
1451 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1452 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1453 line. This is a very efficient way of searching the source base for a
1454 particular regular expression.</dd>
1455
1456 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1457 files in the current directory and then compiles and links the tool that
1458 is the first argument. For example, assuming you are in the directory
1459 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1460 simply running <tt>makellvm llc</tt> will make a build of the current
1461 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1462 causing a re-linking of LLC.<br><br>
1463
1464 <dt><tt><b>NewNightlyTest.pl</b></tt> and
1465 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1466 cron script to generate nightly status reports of the functionality of
1467 tools, and the results can be seen by following the appropriate link on
1468 the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1469
1470 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1471 the tool used to generate register descriptions, instruction set
1472 descriptions, and even assemblers from common TableGen description
1473 files.<br><br>
1474
1475 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1476 syntax-highlighting files which will work with the VIM editor, providing
1477 syntax highlighting support for LLVM assembly files and TableGen
1478 description files. For information on how to use the syntax files, consult
1479 the <tt>README</tt> file in that directory.<br><br>
1480
1481</dl>
1482
1483</div>
1484
1485<!-- ======================================================================= -->
1486<div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1487<div class="doc_text">
1488 <p>This directory contains build scripts and project files for use with
1489 Visual C++. This allows developers on Windows to build LLVM without the need
1490 for Cygwin. The contents of this directory should be considered experimental
1491 at this time.
1492 </p>
1493</div>
1494<!-- *********************************************************************** -->
1495<div class="doc_section">
1496 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1497</div>
1498<!-- *********************************************************************** -->
1499
1500<div class="doc_text">
1501<p>This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
1502so we only include instructiosn for llvm-gcc4.
1503</p>
1504
1505<p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1506from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1507create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1508the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1509<i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1510output.</p>
1511</div>
1512
1513<!-- ======================================================================= -->
1514<div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1515
1516<div class="doc_text">
1517
1518<ol>
1519 <li><p>First, create a simple C file, name it 'hello.c':</p>
1520
1521<div class="doc_code">
1522<pre>
1523#include &lt;stdio.h&gt;
1524
1525int main() {
1526 printf("hello world\n");
1527 return 0;
1528}
1529</pre></div></li>
1530
1531 <li><p>Next, compile the C file into a native executable:</p>
1532
1533 <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1534
1535 <p>Note that llvm-gcc works just like GCC by default. The standard -S and
1536 -c arguments work as usual (producing a native .s or .o file,
1537 respectively).</p></li>
1538
1539 <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1540
1541 <div class="doc_code">
1542 <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1543
1544 <p>The -emit-llvm option can be used with the -S or -c options to emit an
1545 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
1546 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1547 the bitcode file.</p>
1548
1549 <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1550 </p></li>
1551
1552 <li><p>Run the program in both forms. To run the program, use:</p>
1553
1554 <div class="doc_code"><pre>% ./hello</pre></div>
1555
1556 <p>and</p>
1557
1558 <div class="doc_code"><pre>% lli hello.bc</pre></div>
1559
1560 <p>The second examples shows how to invoke the LLVM JIT, <a
1561 href="CommandGuide/html/lli.html">lli</a>.</p></li>
1562
1563 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1564 code:</p>
1565
1566<div class="doc_code">
1567<pre>llvm-dis &lt; hello.bc | less</pre>
1568</div></li>
1569
1570 <li><p>Compile the program to native assembly using the LLC code
1571 generator:</p>
1572
1573 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1574
1575 <li><p>Assemble the native assembly language file into a program:</p>
1576
1577<div class="doc_code">
1578<pre>
1579<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1580
1581<b>Others:</b> % gcc hello.s -o hello.native
1582</pre>
1583</div></li>
1584
1585 <li><p>Execute the native code program:</p>
1586
1587 <div class="doc_code"><pre>% ./hello.native</pre></div>
1588
1589 <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1590 the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1591 </li>
1592
1593</ol>
1594
1595</div>
1596
1597
1598<!-- *********************************************************************** -->
1599<div class="doc_section">
1600 <a name="problems">Common Problems</a>
1601</div>
1602<!-- *********************************************************************** -->
1603
1604<div class="doc_text">
1605
1606<p>If you are having problems building or using LLVM, or if you have any other
1607general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1608Asked Questions</a> page.</p>
1609
1610</div>
1611
1612<!-- *********************************************************************** -->
1613<div class="doc_section">
1614 <a name="links">Links</a>
1615</div>
1616<!-- *********************************************************************** -->
1617
1618<div class="doc_text">
1619
Bill Wendling08f49b92008-07-22 01:10:25 +0000[diff] [blame]1620<p>This document is just an <b>introduction</b> on how to use LLVM to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1621some simple things... there are many more interesting and complicated things
1622that you can do that aren't documented here (but we'll gladly accept a patch
1623if you want to write something up!). For more information about LLVM, check
1624out:</p>
1625
1626<ul>
1627 <li><a href="http://llvm.org/">LLVM homepage</a></li>
1628 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1629 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1630 that Uses LLVM</a></li>
1631</ul>
1632
1633</div>
1634
1635<!-- *********************************************************************** -->
1636
1637<hr>
1638<address>
1639 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]1640 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1641 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1643
1644 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1645 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1646 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
1647 Last modified: $Date$
1648</address>
1649</body>
1650</html>