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2<html>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]3 <head>
4 <title>Getting Started with LLVM System</title>
5 </head>
6
7 <body bgcolor=white>
8 <center><h1>Getting Started with the LLVM System<br><font size=3>By: <a
9 href="mailto:gshi1@uiuc.edu">Guochun Shi</a>,
John Criswellcb27f1e2003-07-01 21:55:57 +0000[diff] [blame]10 <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
11 <a href="mailto:criswell@uiuc.edu">John Criswell</a>, and
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]12 <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>
13 </font></h1></center>
14
15 <!--=====================================================================-->
16 <h2><a name="Contents">Contents</a></h2>
17 <!--=====================================================================-->
18
19 <ul>
20 <li><a href="#overview">Overview</a>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]21 <ol>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]22 <li><a href="#requirements">Requirements</a>
23 <ol>
24 <li><a href="#hardware">Hardware</a>
25 <li><a href="#software">Software</a>
26 </ol>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]27 </ol>
28 <li><a href="#starting">Getting started with LLVM</a>
29 <ol>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]30 <li><a href="#quickstart">Getting Started Quickly (A Summary)</a>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]31 <li><a href="#terminology">Terminology and Notation</tt></a>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]32 <li><a href="#environment">Setting Up Your Environment</a>
John Criswell312a68c2003-07-07 19:27:35 +0000[diff] [blame]33 <li><a href="#unpack">Unpacking the LLVM Archives</a>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]34 <li><a href="#checkout">Checkout LLVM from CVS</a>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]35 <li><a href="#installcf">Install the C Front End</a>
36 <li><a href="#config">Local LLVM Configuration</tt></a>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]37 <li><a href="#compile">Compiling the LLVM Suite Source Code</a>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]38 <li><a href="#objfiles">The Location of LLVM Object Files</tt></a>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]39 </ol>
40 <li><a href="#layout">Program layout</a>
41 <ol>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]42 <li><a href="#cvsdir"><tt>CVS</tt> directories</a>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]43 <li><a href="#include"><tt>llvm/include</tt></a>
44 <li><a href="#lib"><tt>llvm/lib</tt></a>
45 <li><a href="#test"><tt>llvm/test</tt></a>
46 <li><a href="#tools"><tt>llvm/tools</tt></a>
47 </ol>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]48 <li><a href="#cfront">Compiling the LLVM C Front End</a>
49 <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
50 <li><a href="#problems">Common Problems</a>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]51 <li><a href="#links">Links</a>
52 </ul>
53
54
55 <!--=====================================================================-->
56 <center>
57 <h2><a name="overview"><b>Overview</b></a></h2>
58 </center>
59 <!--=====================================================================-->
60
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]61 Welcome to LLVM! In order to get started, you first need to know some
62 basic information.
63
64 <p>
65 First, LLVM comes in two pieces. The first piece is the LLVM suite. This
66 contains all of the tools, libraries, and header files needed to use the
67 low level virtual machine. It also contains a test suite that can be used
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]68 to test the LLVM tools and the C front end.
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]69 <p>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]70 The second piece is the C front end. This component provides a version
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]71 of GCC that compiles C code into LLVM bytecode. Currently, the C front end
72 is a modified version of GCC 3.4 (we track the GCC 3.4 development).
73 Once compiled into LLVM bytecode, a program can be manipulated with the
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]74 LLVM tools from the LLVM suite.
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]75
76 <!--=====================================================================-->
77 <h3><a name="requirements"><b>Requirements</b></a></h3>
78 <!--=====================================================================-->
79
80 Before you begin to use the LLVM system, review the requirements given
81 below. This may save you some trouble by knowing ahead of time what
82 hardware and software you will need.
83
84 <!--=====================================================================-->
85 <h4><a name="hardware"><b>Hardware</b></a></h4>
86 <!--=====================================================================-->
87 LLVM is known to work on the following platforms:
88 <ul>
89 <li> Linux on x86
90 <ul>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]91 <li> Approximately 760 MB of Free Disk Space
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]92 <ul>
93 <li>Source code: 30 MB
94 <li>Object code: 670 MB
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]95 <li>C front end: 60 MB
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]96 </ul>
97 </ul>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]98
99 <p>
100
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]101 <li> Solaris on SparcV9 (Ultrasparc)
102 <ul>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]103 <li> Approximately 1.24 GB of Free Disk Space
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]104 <ul>
105 <li>Source code: 30 MB
106 <li>Object code: 1000 MB
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]107 <li>C front end: 210 MB
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]108 </ul>
109 </ul>
110 </ul>
111
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]112 <p>
113 If you want to compile your own version of the C front end, you will need
114 additional disk space:
115 </p>
116
117 <ul>
118 <li>Linux on x86
119 <ul>
120 <li> Approximately 249 MB of Free Disk Space
121 <ul>
122 <li>Source code: 146 MB
123 <li>Object code: 82 MB
124 <li>Installed binaries: 21 MB
125 </ul>
126 </ul>
127
128 <p>
129
130 <li>Solaris on Sparc
131 <ul>
132 <li> Approximately 264 MB of Free Disk Space
133 <ul>
134 <li>Source code: 146 MB
135 <li>Object code: 93 MB
136 <li>Installed binaries: 25 MB
137 </ul>
138 </ul>
139 </ul>
140
141 <p>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]142 LLVM <i>may</i> compile on other platforms. The LLVM utilities should work
143 on other platforms, so it should be possible to generate and produce LLVM
144 bytecode on unsupported platforms (although bytecode generated on one
145 platform may not work on another platform). However, the code generators
Misha Brukmanc56e5822003-07-03 16:29:36 +0000[diff] [blame]146 and Just-In-Time (JIT) compilers only generate SparcV9 or x86 machine code.
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]147 </p>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]148
149 <!--=====================================================================-->
150 <h4><a name="software"><b>Software</b></a></h4>
151 <!--=====================================================================-->
152 <p>
John Criswell6dd90d22003-07-03 16:43:01 +0000[diff] [blame]153
154 Unpacking the distribution requires the following tools:
155 <dl compact>
156 <dt>GNU Zip (gzip)
157 <dt>GNU Tar
158 <dd>
159 These tools are needed to uncompress and unarchive the software.
160 Regular Solaris <tt>tar</tt> may work for unpacking the TAR archive but
161 is untested.
162 </dl>
163
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]164 Compiling LLVM requires that you have several different software packages
165 installed:
166
167 <dl compact>
168 <dt> GCC
169 <dd>
170 The GNU Compiler Collection must be installed with C and C++ language
171 support. GCC 3.2.x works, and GCC 3.x is generally supported.
172
173 <p>
174 Note that we currently do not support any other C++ compiler.
175 </p>
176
177 <dt> GNU Make
178 <dd>
179 The LLVM build system relies upon GNU Make extensions. Therefore, you
180 will need GNU Make (sometimes known as gmake) to build LLVM.
181 <p>
182
183 <dt> Flex and Bison
184 <dd>
185 The LLVM source code is built using flex and bison. You will not be
186 able to configure and compile LLVM without them.
187 <p>
188
189 <dt> GNU M4
190 <dd>
191 If you are installing Bison on your machine for the first time, you
192 will need GNU M4 (version 1.4 or higher).
193 </dl>
194
195 <p>
196 There are some additional tools that you may want to have when working with
197 LLVM:
198 </p>
199
200 <ul>
201 <li>GNU Autoconf
202 <li>GNU M4
203 <p>
204 If you want to make changes to the configure scripts, you will need
205 GNU autoconf (2.53 or higher), and consequently, GNU M4 (version 1.4
206 or higher).
207 </p>
208 </ul>
209
210
211 <p>The <a href="starting">next section</a> of this guide is meant to get
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]212 you up and running with LLVM and to give you some basic information about
213 the LLVM environment. The <a href"#quickstart">first subsection</a> gives
214 a short summary for those who are already familiar with the system and
215 want to get started as quickly as possible.
216
217 <p>The later sections of this guide describe the <a
John Criswellcb27f1e2003-07-01 21:55:57 +0000[diff] [blame]218 href="#layout">general layout</a> of the the LLVM source-tree, a <a
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]219 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
220 href="#links">links</a> to find more information about LLVM or to get
221 help via e-mail.
222
223 <!--=====================================================================-->
224 <center>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]225 <h2><a name="starting"><b>Getting Started with LLVM</b></a></h2>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]226 </center>
227 <!--=====================================================================-->
228
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]229 <!--=====================================================================-->
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]230 <h3><a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a></h3>
231 <!--=====================================================================-->
232
233 Here's the short story for getting up and running quickly with LLVM:
Chris Lattner96768ea2003-02-14 04:22:13 +0000[diff] [blame]234 <ol>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]235 <li>Install the C front end:
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]236 <ol>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]237 <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt>
238 <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf
239 -</tt>
240 </ol>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]241
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]242 <p>
243
244 <li>Get the Source Code
245 <ul>
246 <li>With the distributed files:
247 <ol>
248 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
249 <li><tt>gunzip --stdout llvm.tar.gz | tar -xvf -</tt>
250 <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf -</tt>
251 <li><tt>cd llvm</tt>
252 </ol>
253
254 <p>
255
256 <li>With anonymous CVS access:
257 <ol>
258 <li>Find the path to the CVS repository containing LLVM (we'll call this <i>CVSROOTDIR</i>).
259 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
260 <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt>
261 <li><tt>cd llvm</tt>
262 </ol>
263 </ul>
264 </ul>
265
266 <p>
267
268 <li>Configure the LLVM Build Environment
269 <ol>
270 <li>Run <tt>configure</tt> to configure the Makefiles and header
271 files for the default platform.
272 Useful options include:
273 <ul>
274 <li><tt>--with-objroot=<i>directory</i></tt>
275 <br>
276 Specify where object files should be placed during the build.
277
278 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
279 <br>
280 Specify where the LLVM C frontend is going to be installed.
281 </ul>
282 </ol>
283
284 <p>
285
286 <li>Build the LLVM Suite
287 <ol>
288 <li>Set your LLVM_LIB_SEARCH_PATH environment variable.
289 <li><tt>gmake -k |& tee gnumake.out
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]290 &nbsp;&nbsp;&nbsp;# this is csh or tcsh syntax</tt>
291 </ol>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]292
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]293 <p>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]294
Chris Lattner96768ea2003-02-14 04:22:13 +0000[diff] [blame]295 </ol>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]296
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]297 <p>See <a href="#environment">Setting Up Your Environment</a> on tips to
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]298 simplify working with the LLVM front-end and compiled tools. See the
299 other sub-sections below for other useful details in working with LLVM,
300 or go straight to <a href="#layout">Program Layout</a> to learn about the
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]301 layout of the source code tree. For information on building the C front
302 end yourself, see <a href="#cfront">Compiling the LLVM C Front End</a> for
303 information.
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]304
305 <!------------------------------------------------------------------------->
306 <h3><a name="terminology">Terminology and Notation</a></h3>
307 <!------------------------------------------------------------------------->
308
309 <p>Throughout this manual, the following names are used to denote paths
310 specific to the local system and working environment. <i>These are not
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]311 environment variables you need to set but just strings used in the rest
312 of this document below</i>. In any of the examples below, simply replace
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]313 each of these names with the appropriate pathname on your local system.
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame]314 All these paths are absolute:</p>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]315 <dl compact>
316 <dt>CVSROOTDIR
317 <dd>
318 This is the path for the CVS repository containing the LLVM source
319 code. Ask the person responsible for your local LLVM installation to
320 give you this path.
321 <p>
322
323 <dt>OBJ_ROOT
324 <dd>
325 This is the top level directory for where the LLVM suite object files
326 will be placed during the build.
327 <p>
328
329 <dt>LLVMGCCDIR
330 <dd>
331 This is the pathname to the location where the LLVM C Front End will
John Criswell6dd90d22003-07-03 16:43:01 +0000[diff] [blame]332 be installed. Note that the C front end does not need to be installed
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]333 during the LLVM suite build; you will just need to know where it will
334 go for configuring the build system and running the test suite later.
335 <p>
John Criswella27028b2003-07-03 16:49:40 +0000[diff] [blame]336 For the pre-built C front end binaries, the LLVMGCCDIR is
337 <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]338
339 <dt>GCCSRC
340 <dd>
341 This is the pathname of the directory where the LLVM C front end source
342 code can be found.
343 <p>
344
345 <dt>GCCOBJ
346 <dd>
347 This is the pathname of the directory where the LLVM C front end object
348 code will be placed during the build. It can be safely removed once
349 the build is complete.
350 </dl>
351
352 <!------------------------------------------------------------------------->
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]353 <h3><a name="environment">Setting Up Your Environment</a></h3>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]354 <!------------------------------------------------------------------------->
355
356 <p>
357 In order to compile and use LLVM, you will need to set some environment
358 variables. There are also some shell aliases which you may find useful.
359 You can set these on the command line, or better yet, set them in your
360 <tt>.cshrc</tt> or <tt>.profile</tt>.
361
362 <dl compact>
363 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt><i>LLVMGCCDIR</i>/llvm-gcc/bytecode-libs</tt>
364 <dd>
365 This environment variable helps the LLVM C front end find bytecode
366 libraries that it will need for compilation.
367 <p>
368
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]369 <dt>alias llvmgcc <i>LLVMGCCDIR</i><tt>/bin/llvm-gcc</tt>
370 <dd>
371 This alias allows you to use the LLVM C front end without putting it in
372 your <tt>PATH</tt> or typing in its complete pathname.
373 </dl>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]374
375 <!------------------------------------------------------------------------->
John Criswell312a68c2003-07-07 19:27:35 +0000[diff] [blame]376 <h3><a name="unpack">Unpacking the LLVM Archives</a></h3>
377 <!------------------------------------------------------------------------->
378
379 <p>
380 If you have the LLVM distribution, you will need to unpack it before you
381 can begin to compile it. LLVM is distributed as a set of four files. Each
382 file is a TAR archive that is compressed with the gzip program.
383 </p>
384
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]385 <p> The four files are as follows:
John Criswell312a68c2003-07-07 19:27:35 +0000[diff] [blame]386 <dl compact>
387 <dt>llvm.tar.gz
388 <dd>This is the source code to the LLVM suite.
389 <p>
390
391 <dt>cfrontend.sparc.tar.gz
392 <dd>This is the binary release of the C front end for Solaris/Sparc.
393 <p>
394
395 <dt>cfrontend.x86.tar.gz
396 <dd>This is the binary release of the C front end for Linux/x86.
397 <p>
398
399 <dt>cfrontend-src.tar.gz
400 <dd>This is the source code release of the C front end.
401 <p>
402 </dl>
403
John Criswell312a68c2003-07-07 19:27:35 +0000[diff] [blame]404 <!------------------------------------------------------------------------->
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]405 <h3><a name="checkout">Checkout LLVM from CVS</a></h3>
406 <!------------------------------------------------------------------------->
407
John Criswell312a68c2003-07-07 19:27:35 +0000[diff] [blame]408 <p>If you have access to our CVS repository, you can get a fresh copy of
409 the entire source code. All you need to do is check it out from CVS as
410 follows:
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]411 <ul>
412 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
413 <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt></p>
414 </ul>
415
416 <p>This will create an '<tt>llvm</tt>' directory in the current
417 directory and fully populate it with the LLVM source code, Makefiles,
418 test directories, and local copies of documentation files.</p>
419
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]420 <p>
421 Note that the C front end is not included in the CVS repository. You
422 should have either downloaded the source, or better yet, downloaded the
423 binary distribution for your platform.
424 </p>
425
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]426 <!------------------------------------------------------------------------->
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]427 <h3><a name="installcf">Install the C Front End</a></h3>
428 <!------------------------------------------------------------------------->
429
430 <p>
431 Before configuring and compiling the LLVM suite, it is best to extract the
432 LLVM C front end. While not used in building, the C front end is used by
433 the LLVM test suite, and its location must be given to the
434 <tt>configure</tt> script before the LLVM suite can be built.
435 </p>
436
437 <p>
438 To install the C front end, do the following:
439 <ol>
440 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt>
441 <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf
442 -</tt>
443 </ol>
444
445 <!------------------------------------------------------------------------->
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]446 <h3><a name="config">Local LLVM Configuration</a></h3>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]447 <!------------------------------------------------------------------------->
448
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]449 <p>Once checked out from the CVS repository, the LLVM suite source code
450 must be configured via the <tt>configure</tt> script. This script sets
451 variables in <tt>llvm/Makefile.config</tt> and
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]452 <tt>llvm/include/Config/config.h</tt>.
453
454 <p>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]455 The following environment variables are used by the <tt>configure</tt>
456 script to configure the build system:
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]457 </p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]458
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]459 <table border=1>
460 <tr>
461 <th>Variable</th>
462 <th>
463 Purpose
464 </th>
465 </tr>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]466
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]467 <tr>
468 <td>CC</td>
469 <td>
470 Tells <tt>configure</tt> which C compiler to use. By default,
471 <tt>configure</tt> will look for the first GCC compiler in
472 <tt>PATH</tt>. Use this variable to override
473 <tt>configure</tt>'s default behavior.
474 </td>
475 </tr>
476
477 <tr>
478 <td>CXX</td>
479 <td>
480 Tells <tt>configure</tt> which C++ compiler to use. By default,
481 <tt>configure</tt> will look for the first GCC compiler in
482 <tt>PATH</tt>. Use this variable to override
483 <tt>configure</tt>'s default behavior.
484 </td>
485 </tr>
486 </table>
487
488 <p>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]489 The following options can be used to set or enable LLVM specific options:
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]490 </p>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]491
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]492 <dl compact>
493 <dt><i>--with-objroot=OBJ_ROOT</i>
494 <dd>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]495 Path to the directory where
496 object files, libraries, and executables should be placed.
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]497 If this is set to <tt>.</tt>, then the object files will be placed
498 within the source code tree. If left unspecified, the default value is
499 <tt>.</tt>.
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]500 (See the Section on <a href=#objfiles>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]501 The Location of LLVM Object Files</a>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]502 for more information.)
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]503 <p>
504 <dt><i>--with-llvmgccdir=LLVMGCCDIR</i>
505 <dd>
506 Path to the location where the LLVM C front end binaries and
507 associated libraries will be installed.
508 <p>
509 <dt><i>--enable-optimized</i>
510 <dd>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]511 Enables optimized compilation (debugging symbols are removed and GCC
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]512 optimization flags are enabled). The default is to use an unoptimized
513 build (also known as a debug build).
514 <p>
515 <dt><i>--enable-jit</i>
516 <dd>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]517 Compile the Just In Time (JIT) functionality. This is not available
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]518 on all platforms. The default is dependent on platform, so it is best
519 to explicitly enable it if you want it.
520 </dl>
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]521
522 In addition to running <tt>configure</tt>, you must set the
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]523 <tt>LLVM_LIB_SEARCH_PATH</tt> environment variable in your startup scripts.
524 This environment variable is used to locate "system" libraries like
525 "<tt>-lc</tt>" and "<tt>-lm</tt>" when linking. This variable should be set
526 to the absolute path for the bytecode-libs subdirectory of the C front-end
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]527 install, or LLVMGCCDIR/llvm-gcc/bytecode-libs. For example, one might
528 set <tt>LLVM_LIB_SEARCH_PATH</tt> to
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]529 <tt>/home/vadve/lattner/local/x86/llvm-gcc/bytecode-libs</tt> for the X86
530 version of the C front-end on our research machines.<p>
531
532 <!------------------------------------------------------------------------->
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]533 <h3><a name="compile">Compiling the LLVM Suite Source Code</a></h3>
534 <!------------------------------------------------------------------------->
535
536 Once you have configured LLVM, you can build it. There are three types of
537 builds:
538
539 <dl compact>
540 <dt>Debug Builds
541 <dd>
542 These builds are the default. They compile the tools and libraries
543 with debugging information.
544 <p>
545
546 <dt>Release (Optimized) Builds
547 <dd>
548 These builds are enabled with the <tt>--enable-optimized</tt> option to
549 <tt>configure</tt>. They compile the tools and libraries with GCC
550 optimizer flags on and strip debugging information from the libraries
551 and executables it generates.
552 <p>
553
554 <dt>Profile Builds
555 <dd>
556 These builds are for use with profiling. They compile profiling
557 information into the code for use with programs like <tt>gprof</tt>.
558 Profile builds must be started by setting variables on the
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]559 <tt>gmake</tt> command line.
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]560 </dl>
561
562 Once you have LLVM configured, you can build it by entering the top level
563 <tt>llvm</tt> directory and issuing the following command:
564 <p>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]565 <tt>gmake</tt>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]566
567 <p>
568 If you have multiple processors in your machine, you may wish to use some
569 of the parallel build options provided by GNU Make. For example, you could
570 use the command:
571 </p>
572
573 <p>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]574 <tt>gmake -j2</tt>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]575
576 <p>
577 There are several other targets which are useful when working with the LLVM
578 source code:
579
580 <dl compact>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]581 <dt><tt>gmake clean</tt>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]582 <dd>
583 Removes all files generated by the build. This includes object files,
584 generated C/C++ files, libraries, and executables.
585 <p>
586
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]587 <dt><tt>gmake distclean</tt>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]588 <dd>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]589 Removes everything that <tt>gmake clean</tt> does, but also removes
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]590 files generated by <tt>configure</tt>. It attempts to return the
591 source tree to the original state in which it was shipped.
592 <p>
593 </dl>
594
595 It is also possible to override default values from <tt>configure</tt> by
596 declaring variables on the command line. The following are some examples:
597
598 <dl compact>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]599 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]600 <dd>
601 Perform a Release (Optimized) build.
602 <p>
603
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]604 <dt><tt>gmake ENABLE_PROFILING=1</tt>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]605 <dd>
606 Perform a Profiling build.
607 <p>
608
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]609 <dt><tt>gmake VERBOSE=1</tt>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]610 <dd>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]611 Print what <tt>gmake</tt> is doing on standard output.
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]612 <p>
613 </dl>
614
615 Every directory in the LLVM source tree includes a <tt>Makefile</tt> to
616 build it and any subdirectories that it contains. Entering any directory
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]617 inside the LLVM source tree and typing <tt>gmake</tt> should rebuild
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]618 anything in or below that directory that is out of date.
619
620 <!------------------------------------------------------------------------->
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]621 <h3><a name="objfiles">The Location of LLVM Object Files</a></h3>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]622 <!------------------------------------------------------------------------->
623
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]624 <p>The LLVM build system sends most output files generated during the build
625 into the directory defined by the variable <i>OBJ_ROOT</i> in
626 <tt>llvm/Makefile.config</tt>, which is set by the <i>--with-objroot</i>
627 option in <tt>configure</tt>. This can be either just your normal LLVM
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]628 source tree or some other directory writable by you. You may wish to put
629 object files on a different filesystem either to keep them from being backed
630 up or to speed up local builds.
631
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]632 <p>
633 If <i>OBJ_ROOT</i> is specified, then the build system will create a
634 directory tree underneath it that resembles the source code's pathname
635 relative to your home directory.
636 </p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]637
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]638 <p>
639 For example, suppose that <i>OBJ_ROOT</i> is set to <tt>/tmp</tt> and the
640 LLVM suite source code is located in <tt>/usr/home/joe/src/llvm</tt>, where
641 <tt>/usr/home/joe</tt> is the home directory of a user named Joe. Then,
642 the object files will be placed in <tt>/tmp/src/llvm</tt>.
643 </p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]644
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]645 <p>
646 The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
647 named after the build type:
648 </p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]649
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]650 <dl compact>
651 <dt>Debug Builds
652 <dd>
653 <dl compact>
654 <dt>Tools
655 <dd><tt><i>OBJ_ROOT</i>/llvm/tools/Debug</tt>
656 <dt>Libraries
657 <dd><tt><i>OBJ_ROOT</i>/llvm/lib/Debug</tt>
658 </dl>
659 <p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]660
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]661 <dt>Release Builds
662 <dd>
663 <dl compact>
664 <dt>Tools
665 <dd><tt><i>OBJ_ROOT</i>/llvm/tools/Release</tt>
666 <dt>Libraries
667 <dd><tt><i>OBJ_ROOT</i>/llvm/lib/Release</tt>
668 </dl>
669 <p>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]670
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]671 <dt>Profile Builds
672 <dd>
673 <dl compact>
674 <dt>Tools
675 <dd><tt><i>OBJ_ROOT</i>/llvm/tools/Profile</tt>
676 <dt>Libraries
677 <dd><tt><i>OBJ_ROOT</i>/llvm/lib/Profile</tt>
678 </dl>
679 </dl>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]680
681 <!--=====================================================================-->
682 <center>
683 <h2><a name="layout"><b>Program Layout</b></a></h2>
684 </center>
685 <!--=====================================================================-->
686
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]687 <p>One useful source of information about the LLVM source base is the LLVM <a
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]688 href="http://www.doxygen.org">doxygen</a> documentation, available at <tt><a
689 href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>. The
690 following is a brief introduction to code layout:</p>
691
692
693 <!------------------------------------------------------------------------->
694 <h3><a name="cvsdir"><tt>CVS</tt> directories</a></h3>
695 <!------------------------------------------------------------------------->
696
697 Every directory checked out of CVS will contain a <tt>CVS</tt> directory;
698 for the most part these can just be ignored.
699
700
701 <!------------------------------------------------------------------------->
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]702 <h3><a name="include"><tt>llvm/include</tt></a></h3>
703 <!------------------------------------------------------------------------->
704
705 This directory contains public header files exported from the LLVM
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]706 library. The three main subdirectories of this directory are:<p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]707
John Criswell8df90e02003-06-11 20:46:40 +0000[diff] [blame]708 <ol>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]709 <li><tt>llvm/include/llvm</tt> - This directory contains all of the LLVM
710 specific header files. This directory also has subdirectories for
711 different portions of LLVM: <tt>Analysis</tt>, <tt>CodeGen</tt>,
712 <tt>Reoptimizer</tt>, <tt>Target</tt>, <tt>Transforms</tt>, etc...
713
714 <li><tt>llvm/include/Support</tt> - This directory contains generic
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]715 support libraries that are independent of LLVM, but are used by LLVM.
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]716 For example, some C++ STL utilities and a Command Line option processing
717 library.
718
719 <li><tt>llvm/include/Config</tt> - This directory contains header files
720 configured by the <tt>configure</tt> script. They wrap "standard" UNIX
721 and C header files. Source code can include these header files which
722 automatically take care of the conditional #includes that the configure
723 script generates.
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]724 </ol>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]725
726 <!------------------------------------------------------------------------->
727 <h3><a name="lib"><tt>llvm/lib</tt></a></h3>
728 <!------------------------------------------------------------------------->
729
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]730 This directory contains most of the source files of the LLVM system. In
731 LLVM almost all
732 code exists in libraries, making it very easy to share code among the
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]733 different <a href="#tools">tools</a>.<p>
734
735 <dl compact>
736 <dt><tt>llvm/lib/VMCore/</tt><dd> This directory holds the core LLVM
737 source files that implement core classes like Instruction and BasicBlock.
738
739 <dt><tt>llvm/lib/AsmParser/</tt><dd> This directory holds the source code
740 for the LLVM assembly language parser library.
741
742 <dt><tt>llvm/lib/ByteCode/</tt><dd> This directory holds code for reading
743 and write LLVM bytecode.
744
745 <dt><tt>llvm/lib/CWriter/</tt><dd> This directory implements the LLVM to C
746 converter.
747
748 <dt><tt>llvm/lib/Analysis/</tt><dd> This directory contains a variety of
749 different program analyses, such as Dominator Information, Call Graphs,
750 Induction Variables, Interval Identification, Natural Loop Identification,
751 etc...
752
753 <dt><tt>llvm/lib/Transforms/</tt><dd> This directory contains the source
754 code for the LLVM to LLVM program transformations, such as Aggressive Dead
755 Code Elimination, Sparse Conditional Constant Propagation, Inlining, Loop
756 Invarient Code Motion, Dead Global Elimination, Pool Allocation, and many
757 others...
758
759 <dt><tt>llvm/lib/Target/</tt><dd> This directory contains files that
760 describe various target architectures for code generation. For example,
761 the llvm/lib/Target/Sparc directory holds the Sparc machine
762 description.<br>
763
764 <dt><tt>llvm/lib/CodeGen/</tt><dd> This directory contains the major parts
765 of the code generator: Instruction Selector, Instruction Scheduling, and
766 Register Allocation.
767
768 <dt><tt>llvm/lib/Reoptimizer/</tt><dd> This directory holds code related
769 to the runtime reoptimizer framework that is currently under development.
770
771 <dt><tt>llvm/lib/Support/</tt><dd> This directory contains the source code
772 that corresponds to the header files located in
773 <tt>llvm/include/Support/</tt>.
774 </dl>
775
776 <!------------------------------------------------------------------------->
777 <h3><a name="test"><tt>llvm/test</tt></a></h3>
778 <!------------------------------------------------------------------------->
779
780 <p>This directory contains regression tests and source code that is used to
781 test the LLVM infrastructure...</p>
782
783 <!------------------------------------------------------------------------->
784 <h3><a name="tools"><tt>llvm/tools</tt></a></h3>
785 <!------------------------------------------------------------------------->
786
787 <p>The <b>tools</b> directory contains the executables built out of the
788 libraries above, which form the main part of the user interface. You can
789 always get help for a tool by typing <tt>tool_name --help</tt>. The
790 following is a brief introduction to the most important tools.</p>
791
792 <dl compact>
793 <dt><tt><b>as</b></tt><dd>The assembler transforms the human readable
794 LLVM assembly to LLVM bytecode.<p>
795
796 <dt><tt><b>dis</b></tt><dd>The disassembler transforms the LLVM bytecode
797 to human readable LLVM assembly. Additionally it can convert LLVM
798 bytecode to C, which is enabled with the <tt>-c</tt> option.<p>
799
800 <dt><tt><b>lli</b></tt><dd> <tt>lli</tt> is the LLVM interpreter, which
801 can directly execute LLVM bytecode (although very slowly...). In addition
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]802 to a simple interpreter, <tt>lli</tt> is also has debugger and tracing
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]803 modes (entered by specifying <tt>-debug</tt> or <tt>-trace</tt> on the
Misha Brukmanc56e5822003-07-03 16:29:36 +0000[diff] [blame]804 command line, respectively). Finally, for architectures that support it
805 (currently only x86 and Sparc), by default, <tt>lli</tt> will function as
806 a Just-In-Time compiler (if the functionality was compiled in), and will
807 execute the code <i>much</i> faster than the interpreter.<p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]808
809 <dt><tt><b>llc</b></tt><dd> <tt>llc</tt> is the LLVM backend compiler,
Misha Brukmanc56e5822003-07-03 16:29:36 +0000[diff] [blame]810 which translates LLVM bytecode to a SPARC or x86 assembly file.<p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]811
812 <dt><tt><b>llvmgcc</b></tt><dd> <tt>llvmgcc</tt> is a GCC based C frontend
813 that has been retargeted to emit LLVM code as the machine code output. It
814 works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
815 -o</tt> options that are typically used. The source code for the
816 <tt>llvmgcc</tt> tool is currently not included in the LLVM cvs tree
817 because it is quite large and not very interesting.<p>
818
819 <ol>
820 <dt><tt><b>gccas</b></tt><dd> This tool is invoked by the
821 <tt>llvmgcc</tt> frontend as the "assembler" part of the compiler. This
822 tool actually assembles LLVM assembly to LLVM bytecode,
John Criswell7a73b802003-06-30 21:59:07 +0000[diff] [blame]823 performs a variety of optimizations,
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]824 and outputs LLVM bytecode. Thus when you invoke <tt>llvmgcc -c x.c -o
825 x.o</tt>, you are causing <tt>gccas</tt> to be run, which writes the
826 <tt>x.o</tt> file (which is an LLVM bytecode file that can be
827 disassembled or manipulated just like any other bytecode file). The
828 command line interface to <tt>gccas</tt> is designed to be as close as
829 possible to the <b>system</b> '<tt>as</tt>' utility so that the gcc
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]830 frontend itself did not have to be modified to interface to a "weird"
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]831 assembler.<p>
832
833 <dt><tt><b>gccld</b></tt><dd> <tt>gccld</tt> links together several LLVM
834 bytecode files into one bytecode file and does some optimization. It is
835 the linker invoked by the gcc frontend when multiple .o files need to be
836 linked together. Like <tt>gccas</tt> the command line interface of
837 <tt>gccld</tt> is designed to match the system linker, to aid
838 interfacing with the GCC frontend.<p>
839 </ol>
840
841 <dt><tt><b>opt</b></tt><dd> <tt>opt</tt> reads LLVM bytecode, applies a
842 series of LLVM to LLVM transformations (which are specified on the command
843 line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
844 command is a good way to get a list of the program transformations
845 available in LLVM.<p>
846
847
848 <dt><tt><b>analyze</b></tt><dd> <tt>analyze</tt> is used to run a specific
849 analysis on an input LLVM bytecode file and print out the results. It is
850 primarily useful for debugging analyses, or familiarizing yourself with
851 what an analysis does.<p>
852
853 </dl>
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]854
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]855 <!--=====================================================================-->
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]856 <h2><center><a name="cfront">Compiling the LLVM C Front End</center></h2>
857 <!--=====================================================================-->
858
859 <p>
860 <b>
861 This step is optional if you have the C front end binary distrubtion for
862 your platform.
863 </b>
864 </p>
865
866 Now that you have the LLVM suite built, you can build the C front end. For
867 those of you that have built GCC before, the process is very similar.
868 <p>
869 Be forewarned, though: the build system for the C front end is not as
870 polished as the rest of the LLVM code, so there will be many warnings and
871 errors that you will need to ignore for now:
872
873 <ol>
874 <li>Ensure that <tt><i>OBJ_ROOT</i>/llvm/tools/Debug</tt> is at the
875 <i>end</i> of your <tt>PATH</tt> environment variable. The front end
876 build needs to know where to find the LLVM tools, but you want to
877 ensure that these tools are not found before the system assembler and
878 linker that you normally use for compilation.
879
880 <li><tt>cd <i>GCCOBJ</i></tt>
881
882 <li>Configure the source code:
883 <ul>
884 <li>On Linux/x86, use
885 <ul>
886 <li><tt><i>GCCSRC</i>/configure --prefix=<i>LLVMGCCDIR</i>
887 --enable-languages=c</tt>
888 </ul>
889
890 <li>On Solaris/Sparc, use
891 <ul>
892 <li><tt><i>GCCSRC</i>/configure --prefix=<i>LLVMGCCDIR</i>
893 --enable-languages=c --target=sparcv9-sun-solaris2</tt>
894 </ul>
895 </ul>
896
897 <li><tt>gmake</tt>
898
899 <li>The build will eventually fail. Don't worry; chances are good that
900 everything that needed to build is built.
901
902 <li><tt>gmake -k install</tt>
903 </ol>
904
905 <p>
906 Once this is done, you should have a built front end compiler in
907 <tt><i>LLVMGCCDIR</i></tt>.
908 </p>
909
910 <!--=====================================================================-->
911 <h2>
912 <center><a name="tutorial">An Example Using the LLVM Tool Chain</center>
913 </h2>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]914 <!--=====================================================================-->
915
916 <ol>
917 <li>First, create a simple C file, name it 'hello.c':
918 <pre>
919 #include &lt;stdio.h&gt;
920 int main() {
921 printf("hello world\n");
922 return 0;
923 }
924 </pre>
925
926 <li>Next, compile the C file into a LLVM bytecode file:<p>
927
928 <tt>% llvmgcc hello.c -o hello</tt><p>
929
930 This will create two result files: <tt>hello</tt> and
931 <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
932 corresponds the the compiled program and the library facilities that it
933 required. <tt>hello</tt> is a simple shell script that runs the bytecode
934 file with <tt>lli</tt>, making the result directly executable.<p>
935
936 <li>Run the program. To make sure the program ran, execute one of the
937 following commands:<p>
John Criswell8df90e02003-06-11 20:46:40 +0000[diff] [blame]938
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]939 <tt>% ./hello</tt><p>
940
941 or<p>
942
943 <tt>% lli hello.bc</tt><p>
944
945 <li>Use the <tt>dis</tt> utility to take a look at the LLVM assembly
946 code:<p>
947
948 <tt>% dis < hello.bc | less</tt><p>
949
950 <li>Compile the program to native Sparc assembly using the code
Misha Brukmanc56e5822003-07-03 16:29:36 +0000[diff] [blame]951 generator (assuming you are currently on a Sparc system):<p>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]952
953 <tt>% llc hello.bc -o hello.s</tt><p>
954
955 <li>Assemble the native sparc assemble file into a program:<p>
956
957 <tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc</tt><p>
958
959 <li>Execute the native sparc program:<p>
960
961 <tt>% ./hello.sparc</tt><p>
962
963 </ol>
964
965
966 <!--=====================================================================-->
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]967 <h2>
968 <center><a name="problems">Common Problems</a></center>
969 </h2>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]970 <!--=====================================================================-->
971
972 Below are common problems and their remedies:
973
974 <dl compact>
975 <dt><b>When I run configure, it finds the wrong C compiler.</b>
976 <dd>
977 The <tt>configure</tt> script attempts to locate first <tt>gcc</tt> and
978 then <tt>cc</tt>, unless it finds compiler paths set in <tt>CC</tt> and
979 <tt>CXX</tt> for the C and C++ compiler, respectively.
980
981 If <tt>configure</tt> finds the wrong compiler, either adjust your
982 <tt>PATH</tt> environment variable or set <tt>CC</tt> and <tt>CXX</tt>
983 explicitly.
984 <p>
985
986 <dt><b>I compile the code, and I get some error about /localhome</b>.
987 <dd>
988 There are several possible causes for this. The first is that you
989 didn't set a pathname properly when using <tt>configure</tt>, and it
990 defaulted to a pathname that we use on our research machines.
991 <p>
992 Another possibility is that we hardcoded a path in our Makefiles. If
993 you see this, please email the LLVM bug mailing list with the name of
994 the offending Makefile and a description of what is wrong with it.
995
996 <dt><b>The <tt>configure</tt> script finds the right C compiler, but it
997 uses the LLVM linker from a previous build. What do I do?</b>
998 <dd>
999 The <tt>configure</tt> script uses the <tt>PATH</tt> to find
1000 executables, so if it's grabbing the wrong linker/assembler/etc, there
1001 are two ways to fix it:
1002 <ol>
1003 <li>Adjust your <tt>PATH</tt> environment variable so that the
1004 correct program appears first in the <tt>PATH</tt>. This may work,
1005 but may not be convenient when you want them <i>first</i> in your
1006 path for other work.
1007 <p>
1008
1009 <li>Run <tt>configure</tt> with an alternative <tt>PATH</tt> that
1010 is correct. In a Borne compatible shell, the syntax would be:
1011 <p>
1012 <tt>PATH=<the path without the bad program> ./configure ...</tt>
1013 <p>
1014 This is still somewhat inconvenient, but it allows
1015 <tt>configure</tt> to do its work without having to adjust your
1016 <tt>PATH</tt> permanently.
1017 </ol>
1018 </dl>
1019
1020 <!--=====================================================================-->
John Criswell0b459202003-07-08 20:35:59 +0000[diff] [blame^]1021 <h2><center><a name="links">Links</a></center></h2>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]1022 <!--=====================================================================-->
1023
1024 <p>This document is just an <b>introduction</b> to how to use LLVM to do
1025 some simple things... there are many more interesting and complicated things
1026 that you can do that aren't documented here (but we'll gladly accept a patch
1027 if you want to write something up!). For more information about LLVM, check
1028 out:</p>
1029
1030 <ul>
1031 <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
1032 <li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
John Criswellce760f62003-07-03 16:01:38 +0000[diff] [blame]1033 <li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project that Uses LLVM</a></li>
John Criswell85ed3612003-06-12 19:34:44 +0000[diff] [blame]1034 </ul>
1035
1036 <hr>
1037
1038 If you have any questions or run into any snags (or you have any
1039 additions...), please send an email to
1040 <a href="mailto:sabre@nondot.org">Chris Lattner</a>.</p>
1041
1042 <!-- Created: Mon Jul 1 02:29:02 CDT 2002 -->
1043 <!-- hhmts start -->
1044Last modified: Tue Jun 3 22:06:43 CDT 2003
1045<!-- hhmts end -->
1046 </body>
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]1047</html>