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11 <div class="doc_title">
12 Getting Started with the LLVM System
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>
20 <li><a href="#hardware">Hardware</a>
21 <li><a href="#software">Software</a>
22 <li><a href="#brokengcc">Broken versions of GCC</a>
25 <li><a href="#starting">Getting Started with LLVM</a>
27 <li><a href="#terminology">Terminology and Notation</a>
28 <li><a href="#environment">Setting Up Your Environment</a>
29 <li><a href="#unpack">Unpacking the LLVM Archives</a>
30 <li><a href="#checkout">Checkout LLVM from CVS</a>
31 <li><a href="#installcf">Install the GCC Front End</a>
32 <li><a href="#config">Local LLVM Configuration</a>
33 <li><a href="#compile">Compiling the LLVM Suite Source Code</a>
34 <li><a href="#objfiles">The Location of LLVM Object Files</a>
35 <li><a href="#optionalconfig">Optional Configuration Items</a>
38 <li><a href="#layout">Program layout</a>
40 <li><a href="#cvsdir"><tt>CVS</tt> directories</a>
41 <li><a href="#examples"><tt>llvm/examples</tt></a>
42 <li><a href="#include"><tt>llvm/include</tt></a>
43 <li><a href="#lib"><tt>llvm/lib</tt></a>
44 <li><a href="#projects"><tt>llvm/projects</tt></a>
45 <li><a href="#runtime"><tt>llvm/runtime</tt></a>
46 <li><a href="#test"><tt>llvm/test</tt></a>
47 <li><a href="#llvmtest"><tt>llvm-test</tt></a>
48 <li><a href="#tools"><tt>llvm/tools</tt></a>
49 <li><a href="#utils"><tt>llvm/utils</tt></a>
50 <li><a href="#win32"><tt>llvm/win32</tt></a>
53 <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
54 <li><a href="#problems">Common Problems</a>
55 <li><a href="#links">Links</a>
58 <div class="doc_author">
60 <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
61 <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
62 <a href="http://misha.brukman.net">Misha Brukman</a>,
63 <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and
64 <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>.
69 <!-- *********************************************************************** -->
70 <div class="doc_section">
71 <a name="overview"><b>Overview</b></a>
73 <!-- *********************************************************************** -->
75 <div class="doc_text">
77 <p>Welcome to LLVM! In order to get started, you first need to know some
78 basic information.</p>
80 <p>First, LLVM comes in two pieces. The first piece is the LLVM suite. This
81 contains all of the tools, libraries, and header files needed to use the low
82 level virtual machine. It contains an assembler, disassembler, bytecode
83 analyzer, and bytecode optimizer. It also contains a test suite that can be
84 used to test the LLVM tools and the GCC front end.</p>
86 <p>The second piece is the GCC front end. This component provides a version of
87 GCC that compiles C and C++ code into LLVM bytecode. Currently, the GCC front
88 end is a modified version of GCC 3.4 (we track the GCC 3.4 development). Once
89 compiled into LLVM bytecode, a program can be manipulated with the LLVM tools
90 from the LLVM suite.</p>
93 There is a third, optional piece called llvm-test. It is a suite of programs
94 with a testing harness that can be used to further test LLVM's functionality
100 <!-- *********************************************************************** -->
101 <div class="doc_section">
102 <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
104 <!-- *********************************************************************** -->
106 <div class="doc_text">
108 <p>Here's the short story for getting up and running quickly with LLVM:</p>
111 <li>Read the documentation.</li>
112 <li>Read the documentation.</li>
113 <li>Remember that you were warned twice about reading the documentation.</li>
114 <li>Install the GCC front end:
116 <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt>
117 <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf -</tt>
118 <li><tt>cd cfrontend/<i>platform</i><br>
122 <li>Get the Source Code
124 <li>With the distributed files:
126 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
127 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
128 <li><tt>cd llvm</tt></li>
131 <li>With anonymous CVS access (or use a <a href="#mirror">mirror</a>):
133 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
135 :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt></li>
136 <li>Hit the return key when prompted for the password.
137 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm
139 <li><tt>cd llvm</tt></li>
140 <li><tt>cvs up -P -d</tt></li>
144 <li>Get the Test Suite Source Code (<em>optional</em>)
146 <li>With the distributed files:
148 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
149 <li><tt>cd llvm/projects</tt>
150 <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
151 <li><tt>cd ..</tt></li>
154 <li>With anonymous CVS access (or use a <a href="#mirror">mirror</a>):
156 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
157 <li><tt>cd llvm/projects</tt>
159 :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt></li>
160 <li>Hit the return key when prompted for the password.
161 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm
162 co llvm-test</tt></li>
163 <li><tt>cd llvm-test</tt></li>
164 <li><tt>cvs up -P -d</tt></li>
165 <li><tt>cd ..</tt></li>
170 <li>Configure the LLVM Build Environment
172 <li>Change directory to where you want to store the LLVM object
173 files and run <tt>configure</tt> to configure the Makefiles and
174 header files for the default platform. Useful options include:
176 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
177 <p>Specify the full pathname of where the LLVM GCC frontend is
179 <li><tt>--enable-spec2000=<i>directory</i></tt>
180 <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
181 benchmarks should be available in
182 <tt><i>directory</i></tt>.</p></li>
186 <li>Build the LLVM Suite:
188 <li>Set your LLVM_LIB_SEARCH_PATH environment variable.</li>
189 <li><tt>gmake -k |& tee gnumake.out
190 # this is csh or tcsh syntax</tt></li>
191 <li>If you get an "internal compiler error (ICE)" see <a href="#brokengcc">below</a>.</li>
196 <p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
197 detailed information on configuring and compiling LLVM. See <a
198 href="#environment">Setting Up Your Environment</a> for tips that simplify
199 working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
200 Layout</a> to learn about the layout of the source code tree.</p>
204 <!-- *********************************************************************** -->
205 <div class="doc_section">
206 <a name="requirements"><b>Requirements</b></a>
208 <!-- *********************************************************************** -->
210 <div class="doc_text">
212 <p>Before you begin to use the LLVM system, review the requirements given below.
213 This may save you some trouble by knowing ahead of time what hardware and
214 software you will need.</p>
218 <!-- ======================================================================= -->
219 <div class="doc_subsection">
220 <a name="hardware"><b>Hardware</b></a>
223 <div class="doc_text">
225 <p>LLVM is known to work on the following platforms:</p>
227 <table cellpadding="3">
235 <td>x86<sup>1</sup></td>
240 <td>V9 (Ultrasparc)</td>
245 <td>x86<sup>1</sup></td>
249 <td>MacOS X<sup>2</sup></td>
254 <td>Cygwin/Win32</td>
255 <td>x86<sup>1</sup></td>
260 <p>LLVM has partial support for the following platforms:</p>
270 <td>x86<sup>1</sup></td>
271 <td>Visual Studio .NET<sup>4,5</sup>, MinGW</td>
273 <td>AIX<sup>3,4</sup></td>
278 <td>Linux<sup>3,5</sup></td>
286 <sup>1</sup> Code generation supported for Pentium processors and up<br>
287 <sup>2</sup> Code generation supported for 32-bit ABI only<br>
288 <sup>3</sup> No native code generation<br>
289 <sup>4</sup> Build is not complete: one or more tools don't link<br>
290 <sup>5</sup> The GCC-based C/C++ frontend does not build<br>
293 <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
294 mode, depending on the system (because of all the debug info), and the libraries
295 appear in more than one of the tools that get linked, so there is some
296 duplication. If you do not need many of the tools and you are space-conscious,
297 you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
298 build requires considerably less space.</p>
300 <p>The LLVM suite <i>may</i> compile on other platforms, but it is not
301 guaranteed to do so. If compilation is successful, the LLVM utilities should be
302 able to assemble, disassemble, analyze, and optimize LLVM bytecode. Code
303 generation should work as well, although the generated native code may not work
304 on your platform.</p>
306 <p>The GCC front end is not very portable at the moment. If you want to get it
307 to work on another platform, you can download a copy of the source and <a
308 href="CFEBuildInstrs.html">try to compile it</a> on your platform.</p>
312 <!-- ======================================================================= -->
313 <div class="doc_subsection"><a name="software"><b>Software</b></a></div>
314 <div class="doc_text">
315 <p>Compiling LLVM requires that you have several software packages
316 installed. The table below lists those required packages. The Package column
317 is the usual name for the software package that LLVM depends on. The Version
318 column provides "known to work" versions of the package. The Notes column
319 describes how LLVM uses the package and provides other details.</p>
321 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
324 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
325 <td>3.79, 3.79.1</td>
326 <td>Makefile/build processor</td>
330 <td><a href="http://gcc.gnu.org">GCC</a></td>
332 <td>C/C++ compiler (<a href="#Note3">Note 3</a>)</td>
336 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
338 <td>LEX compiler</td>
342 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
344 <td>YACC compiler</td>
348 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
350 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
354 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
356 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
360 <td><a href="http://expect.nist.gov/">expect</a></td>
362 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
366 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
368 <td>Macro processor for configuration (<a href="#Note1">Note 1</a>)</td>
372 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
374 <td>Configuration script builder (<a href="#Note1">Note 1</a>)</td>
378 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
380 <td>aclocal macro generator (<a href="#Note1">Note 1</a>)</td>
384 <td><a href="http://www.perl.com/download.csp">perl</a></td>
386 <td>Nightly tester, utilities</td>
390 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
392 <td>Shared library manager (<a href="#Note1">Note 1</a>)</td>
396 <td><a href="https://www.cvshome.org/downloads.html">CVS</a></td>
398 <td>CVS access to LLVM (<a href="#Note4">Note 4</a>)</td>
405 <li><a name="Note1">If you want to make changes to the configure scripts,
406 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
407 or higher). You will also need automake (1.9.2). We only use aclocal
408 from that package.</a></li>
409 <li><a name="Note2">Only needed if you want to run the automated test
410 suite in the <tt>test</tt> directory.</a></li>
412 <li><a name="Note3">Only the C and C++ languages are needed so there's no
413 need to build the other languages for LLVM's purposes.</a> See
414 <a href="#brokengcc">below</a> for specific version info.
416 <li><a name="Note4">You only need CVS if you intend to build from the
417 latest LLVM sources. If you're working from a release distribution, you
418 don't need CVS.</a></li>
420 <p>Additionally, your compilation host is expected to have the usual
421 plethora of Unix utilities. Specifically:</p>
423 <li><b>ar</b> - archive library builder</li>
424 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
425 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
426 <li><b>chmod</b> - change permissions on a file</li>
427 <li><b>cat</b> - output concatenation utility</li>
428 <li><b>cp</b> - copy files</li>
429 <li><b>date</b> - print the current date/time </li>
430 <li><b>echo</b> - print to standard output</li>
431 <li><b>egrep</b> - extended regular expression search utility</li>
432 <li><b>etags</b> - C/C++ tag file creator for vim/emacs</li>
433 <li><b>find</b> - find files/dirs in a file system</li>
434 <li><b>grep</b> - regular expression search utility</li>
435 <li><b>gzip*</b> - gzip command for distribution generation</li>
436 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
437 <li><b>install</b> - install directories/files </li>
438 <li><b>mkdir</b> - create a directory</li>
439 <li><b>mv</b> - move (rename) files</li>
440 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
441 <li><b>rm</b> - remove (delete) files and directories</li>
442 <li><b>sed</b> - stream editor for transforming output</li>
443 <li><b>sh</b> - Bourne shell for make build scripts</li>
444 <li><b>tar</b> - tape archive for distribution generation</li>
445 <li><b>test</b> - test things in file system</li>
446 <li><b>unzip*</b> - unzip command for distribution checking</li>
447 <li><b>zip*</b> - zip command for distribution generation</li>
451 <!-- ======================================================================= -->
452 <div class="doc_subsection">
453 <a name="brokengcc">Broken versions of GCC</a>
456 <div class="doc_text">
458 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
459 bugs in the compiler. In particular, several versions of GCC crash when trying
460 to compile LLVM. We routinely use GCC 3.3.3 and GCC 3.4.0 and have had success
461 with them. Other versions of GCC will probably work as well. GCC versions listed
462 here are known to not work. If you are using one of these versions, please try
463 to upgrade your GCC to something more recent. If you run into a problem with a
464 version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
465 us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
466 of GCC you are using.
469 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
470 problems in the STL that effectively prevent it from compiling LLVM.
473 <p><b>GCC 3.2.2</b>: This version of GCC fails to compile LLVM.</p>
475 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
476 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
477 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
482 <!-- *********************************************************************** -->
483 <div class="doc_section">
484 <a name="starting"><b>Getting Started with LLVM</b></a>
486 <!-- *********************************************************************** -->
488 <div class="doc_text">
490 <p>The remainder of this guide is meant to get you up and running with
491 LLVM and to give you some basic information about the LLVM environment.</p>
493 <p>The later sections of this guide describe the <a
494 href="#layout">general layout</a> of the the LLVM source tree, a <a
495 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
496 href="#links">links</a> to find more information about LLVM or to get
500 <!-- ======================================================================= -->
501 <div class="doc_subsection">
502 <a name="terminology">Terminology and Notation</a>
505 <div class="doc_text">
507 <p>Throughout this manual, the following names are used to denote paths
508 specific to the local system and working environment. <i>These are not
509 environment variables you need to set but just strings used in the rest
510 of this document below</i>. In any of the examples below, simply replace
511 each of these names with the appropriate pathname on your local system.
512 All these paths are absolute:</p>
517 This is the top level directory of the LLVM source tree.
522 This is the top level directory of the LLVM object tree (i.e. the
523 tree where object files and compiled programs will be placed. It
524 can be the same as SRC_ROOT).
529 This is the where the LLVM GCC Front End is installed.
531 For the pre-built GCC front end binaries, the LLVMGCCDIR is
532 <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
537 <!-- ======================================================================= -->
538 <div class="doc_subsection">
539 <a name="environment">Setting Up Your Environment</a>
542 <div class="doc_text">
545 In order to compile and use LLVM, you will need to set some environment
546 variables. There are also some shell aliases which you may find useful.
547 You can set these on the command line, or better yet, set them in your
548 <tt>.cshrc</tt> or <tt>.profile</tt>.
551 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt><i>LLVMGCCDIR</i>/lib</tt>
553 This environment variable helps the LLVM GCC front end find bytecode
554 libraries that it will need for compilation.
557 <dt>alias llvmgcc <i>LLVMGCCDIR</i><tt>/bin/gcc</tt>
558 <dt>alias llvmg++ <i>LLVMGCCDIR</i><tt>/bin/g++</tt>
560 These aliases allow you to use the LLVM C and C++ front ends without putting
561 them in your <tt>PATH</tt> or typing in their complete pathnames.
566 <!-- ======================================================================= -->
567 <div class="doc_subsection">
568 <a name="unpack">Unpacking the LLVM Archives</a>
571 <div class="doc_text">
574 If you have the LLVM distribution, you will need to unpack it before you
575 can begin to compile it. LLVM is distributed as a set of two files: the LLVM
576 suite and the LLVM GCC front end compiled for your platform. There is an
577 additional test suite that is optional. Each file is a TAR archive that is
578 compressed with the gzip program.
581 <p> The files are as follows:
583 <dt><tt>llvm-1.4.tar.gz</tt></dt>
584 <dd>This is the source code for the LLVM libraries and tools.<br/></dd>
586 <dt><tt>llvm-test-1.4.tar.gz</tt></dt>
587 <dd>This is the source code for the LLVM test suite.</tt></dd>
589 <dt><tt>cfrontend-1.4.source.tar.gz</tt></dt>
590 <dd>This is the source release of the GCC front end.<br/></dd>
592 <dt><tt>cfrontend-1.4.sparc-sun-solaris2.8.tar.gz</tt></dt>
593 <dd>This is the binary release of the GCC front end for Solaris/Sparc.
596 <dt><tt>cfrontend-1.4.i686-redhat-linux-gnu.tar.gz</tt></dt>
597 <dd>This is the binary release of the GCC front end for Linux/x86.<br/></dd>
599 <dt><tt>cfrontend-1.4.i386-unknown-freebsd5.1.tar.gz</tt></dt>
600 <dd>This is the binary release of the GCC front end for FreeBSD/x86.<br/></dd>
602 <dt><tt>cfrontend-1.4.powerpc-apple-darwin7.6.0.tar.gz</tt></dt>
603 <dd>This is the binary release of the GCC front end for MacOS X/PPC.<br/></dd>
608 <!-- ======================================================================= -->
609 <div class="doc_subsection">
610 <a name="checkout">Checkout LLVM from CVS</a>
613 <div class="doc_text">
615 <p>If you have access to our CVS repository, you can get a fresh copy of
616 the entire source code. All you need to do is check it out from CVS as
620 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
621 <li><tt>cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
622 <li>Hit the return key when prompted for the password.
623 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co
627 <p>This will create an '<tt>llvm</tt>' directory in the current
628 directory and fully populate it with the LLVM source code, Makefiles,
629 test directories, and local copies of documentation files.</p>
631 <p>If you want to get a specific release (as opposed to the most recent
632 revision), you can specify a label. The following releases have the following
636 <li>Release 1.4: <b>RELEASE_14</b></li>
637 <li>Release 1.3: <b>RELEASE_13</b></li>
638 <li>Release 1.2: <b>RELEASE_12</b></li>
639 <li>Release 1.1: <b>RELEASE_11</b></li>
640 <li>Release 1.0: <b>RELEASE_1</b></li>
643 <p>If you would like to get the LLVM test suite (a separate package as of 1.4),
644 you get it from the CVS repository:</p>
647 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-test
649 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
650 configured by the LLVM configure script as well as automatically updated when
651 you run <tt>cvs update</tt>.</p>
653 <p>If you would like to get the GCC front end source code, you can also get it
654 from the CVS repository:</p>
657 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-gcc
660 <p>Please note that you must follow <a href="CFEBuildInstrs.html">these
661 instructions</a> to successfully build the LLVM GCC front-end.</p>
665 <!-- ======================================================================= -->
666 <div class="doc_subsubsection">
667 <a name="mirrors">LLVM CVS Mirrors</a>
670 <div class="doc_text">
672 <p>If the main CVS server is overloaded or inaccessible, you can try one of
673 these user-hosted mirrors:</p>
676 <li><a href="http://llvm.x10sys.com/">Mirror hosted by eXtensible Systems
681 <!-- ======================================================================= -->
682 <div class="doc_subsection">
683 <a name="installcf">Install the GCC Front End</a>
686 <div class="doc_text">
688 <p>Before configuring and compiling the LLVM suite, you need to extract the LLVM
689 GCC front end from the binary distribution. It is used for building the
690 bytecode libraries later used by the GCC front end for linking programs, and its
691 location must be specified when the LLVM suite is configured.</p>
693 <p>To install the GCC front end, do the following:</p>
696 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
697 <li><tt>gunzip --stdout cfrontend-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
701 <p>Next, you will need to fix your system header files:</p>
703 <p><tt>cd cfrontend/<i>platform</i><br>
704 ./fixheaders</tt></p>
706 <p>The binary versions of the GCC front end may not suit all of your needs. For
707 example, the binary distribution may include an old version of a system header
708 file, not "fix" a header file that needs to be fixed for GCC, or it may be
709 linked with libraries not available on your system.</p>
711 <p>In cases like these, you may want to try <a
712 href="CFEBuildInstrs.html">building the GCC front end from source.</a> This is
713 not for the faint of heart, so be forewarned.</p>
717 <!-- ======================================================================= -->
718 <div class="doc_subsection">
719 <a name="config">Local LLVM Configuration</a>
722 <div class="doc_text">
724 <p>Once checked out from the CVS repository, the LLVM suite source code must be
725 configured via the <tt>configure</tt> script. This script sets variables in the
726 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
727 <tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
728 the Makefiles needed to begin building LLVM.</p>
730 <p>The following environment variables are used by the <tt>configure</tt>
731 script to configure the build system:</p>
734 <tr><th>Variable</th><th>Purpose</th></tr>
737 <td>Tells <tt>configure</tt> which C compiler to use. By default,
738 <tt>configure</tt> will look for the first GCC C compiler in
739 <tt>PATH</tt>. Use this variable to override
740 <tt>configure</tt>'s default behavior.</td>
744 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
745 <tt>configure</tt> will look for the first GCC C++ compiler in
746 <tt>PATH</tt>. Use this variable to override
747 <tt>configure</tt>'s default behavior.</td>
751 <p>The following options can be used to set or enable LLVM specific options:</p>
754 <dt><i>--with-llvmgccdir=LLVMGCCDIR</i></dt>
756 Path to the location where the LLVM GCC front end binaries and
757 associated libraries were installed. This must be specified as an
761 <dt><i>--with-tclinclude</i></dt>
762 <dd>Path to the tcl include directory under which the <tt>tclsh</tt> can be
763 found. Use this if you have multiple tcl installations on your machine and you
764 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
765 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
766 option, the LLVM configure script will search for tcl 8.4 and 8.3 releases.
769 <dt><i>--enable-optimized</i></dt>
771 Enables optimized compilation by default (debugging symbols are removed
772 and GCC optimization flags are enabled). The default is to use an
773 unoptimized build (also known as a debug build).
776 <dt><i>--enable-jit</i></dt>
778 Compile the Just In Time (JIT) compiler functionality. This is not
780 on all platforms. The default is dependent on platform, so it is best
781 to explicitly enable it if you want it.
784 <dt><i>--enable-doxygen</i></dt>
785 <dd>Look for the doxygen program and enable construction of doxygen based
786 documentation from the source code. This is disabled by default because
787 generating the documentation can take a long time and producess 100s of
788 megabytes of output.</dd>
791 <p>To configure LLVM, follow these steps:</p>
794 <li>Change directory into the object root directory:
796 <tt>cd <i>OBJ_ROOT</i></tt>
799 <li>Run the <tt>configure</tt> script located in the LLVM source tree:
801 <tt><i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</tt>
805 <p>In addition to running <tt>configure</tt>, you must set the
806 <tt>LLVM_LIB_SEARCH_PATH</tt> environment variable in your startup shell
807 scripts. This environment variable is used to locate "system" libraries like
808 "<tt>-lc</tt>" and "<tt>-lm</tt>" when linking. This variable should be set to
809 the absolute path of the <tt>lib</tt> subdirectory of the GCC front
810 end, or <i>LLVMGCCDIR</i>/<tt>lib</tt>. For example, one might set
811 <tt>LLVM_LIB_SEARCH_PATH</tt> to
812 <tt>/home/vadve/lattner/local/x86/llvm-gcc/lib</tt> for the x86
813 version of the GCC front end on our research machines.</p>
817 <!-- ======================================================================= -->
818 <div class="doc_subsection">
819 <a name="compile">Compiling the LLVM Suite Source Code</a>
822 <div class="doc_text">
824 <p>Once you have configured LLVM, you can build it. There are three types of
830 These builds are the default when one types <tt>gmake</tt> (unless the
831 <tt>--enable-optimized</tt> option was used during configuration). The
832 build system will compile the tools and libraries with debugging
836 <dt>Release (Optimized) Builds
838 These builds are enabled with the <tt>--enable-optimized</tt> option to
839 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
840 <tt>gmake</tt> command line. For these builds, the build system will
841 compile the tools and libraries with GCC optimizations enabled and strip
842 debugging information from the libraries and executables it generates.
847 These builds are for use with profiling. They compile profiling
848 information into the code for use with programs like <tt>gprof</tt>.
849 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
850 on the <tt>gmake</tt> command line.
853 <p>Once you have LLVM configured, you can build it by entering the
854 <i>OBJ_ROOT</i> directory and issuing the following command:</p>
856 <p><tt>gmake</tt></p>
858 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
859 are using a version of GCC that is known not to compile LLVM.</p>
862 If you have multiple processors in your machine, you may wish to use some of
863 the parallel build options provided by GNU Make. For example, you could use the
866 <p><tt>gmake -j2</tt></p>
868 <p>There are several special targets which are useful when working with the LLVM
872 <dt><tt>gmake clean</tt>
874 Removes all files generated by the build. This includes object files,
875 generated C/C++ files, libraries, and executables.
878 <dt><tt>gmake dist-clean</tt>
880 Removes everything that <tt>gmake clean</tt> does, but also removes files
881 generated by <tt>configure</tt>. It attempts to return the source tree to the
882 original state in which it was shipped.
885 <dt><tt>gmake install</tt>
887 Installs LLVM header files, libraries, tools, and documentation in a
889 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
890 defaults to <tt>/usr/local</tt>.
893 <dt><tt>gmake -C runtime install-bytecode</tt>
895 Assuming you built LLVM into $OBJDIR, when this command is run, it will
896 install bytecode libraries into the GCC front end's bytecode library
897 directory. If you need to update your bytecode libraries,
898 this is the target to use once you've built them.
902 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
903 details on these <tt>make</tt> targets and descriptions of other targets
906 <p>It is also possible to override default values from <tt>configure</tt> by
907 declaring variables on the command line. The following are some examples:</p>
910 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
912 Perform a Release (Optimized) build.
915 <dt><tt>gmake ENABLE_PROFILING=1</tt>
917 Perform a Profiling build.
920 <dt><tt>gmake VERBOSE=1</tt>
922 Print what <tt>gmake</tt> is doing on standard output.
925 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
926 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
927 the standard output. This also implies <tt>VERBOSE=1</tt>.
931 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
932 it and any subdirectories that it contains. Entering any directory inside the
933 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
934 that directory that is out of date.</p>
938 <!-- ======================================================================= -->
939 <div class="doc_subsection">
940 <a name="objfiles">The Location of LLVM Object Files</a>
943 <div class="doc_text">
945 <p>The LLVM build system is capable of sharing a single LLVM source tree among
946 several LLVM builds. Hence, it is possible to build LLVM for several different
947 platforms or configurations using the same source tree.</p>
949 <p>This is accomplished in the typical autoconf manner:</p>
952 <li><p>Change directory to where the LLVM object files should live:</p>
954 <p><tt>cd <i>OBJ_ROOT</i></tt></p></li>
956 <li><p>Run the <tt>configure</tt> script found in the LLVM source
959 <p><tt><i>SRC_ROOT</i>/configure</tt></p></li>
962 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
963 named after the build type:</p>
970 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
972 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
980 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
982 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
990 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
992 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
998 <!-- ======================================================================= -->
999 <div class="doc_subsection">
1000 <a name="optionalconfig">Optional Configuration Items</a>
1003 <div class="doc_text">
1006 If you're running on a linux system that supports the "<a
1007 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">
1009 module, and you have root access on the system, you can set your system up to
1010 execute LLVM bytecode files directly. To do this, use commands like this (the
1011 first command may not be required if you are already using the module):</p>
1014 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1015 $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
1016 $ chmod u+x hello.bc (if needed)
1021 This allows you to execute LLVM bytecode files directly. Thanks to Jack
1022 Cummings for pointing this out!
1028 <!-- *********************************************************************** -->
1029 <div class="doc_section">
1030 <a name="layout"><b>Program Layout</b></a>
1032 <!-- *********************************************************************** -->
1034 <div class="doc_text">
1036 <p>One useful source of information about the LLVM source base is the LLVM <a
1037 href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1038 href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>.
1039 The following is a brief introduction to code layout:</p>
1043 <!-- ======================================================================= -->
1044 <div class="doc_subsection"><a name="cvsdir"><tt>CVS</tt> directories</a></div>
1045 <div class="doc_text">
1046 <p>Every directory checked out of CVS will contain a <tt>CVS</tt> directory; for
1047 the most part these can just be ignored.</p>
1050 <!-- ======================================================================= -->
1051 <div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1052 <div class="doc_text">
1053 <p>This directory contains some simple examples of how to use the LLVM IR and
1057 <!-- ======================================================================= -->
1058 <div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1059 <div class="doc_text">
1061 <p>This directory contains public header files exported from the LLVM
1062 library. The three main subdirectories of this directory are:</p>
1065 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1066 <dd>This directory contains all of the LLVM specific header files. This
1067 directory also has subdirectories for different portions of LLVM:
1068 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1071 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1072 <dd>This directory contains generic support libraries that are provided with
1073 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1074 and a Command Line option processing library store their header files here.
1077 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1078 <dd>This directory contains header files configured by the <tt>configure</tt>
1079 script. They wrap "standard" UNIX and C header files. Source code can
1080 include these header files which automatically take care of the conditional
1081 #includes that the <tt>configure</tt> script generates.</dd>
1085 <!-- ======================================================================= -->
1086 <div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1087 <div class="doc_text">
1089 <p>This directory contains most of the source files of the LLVM system. In LLVM,
1090 almost all code exists in libraries, making it very easy to share code among the
1091 different <a href="#tools">tools</a>.</p>
1094 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1095 <dd> This directory holds the core LLVM source files that implement core
1096 classes like Instruction and BasicBlock.</dd>
1098 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1099 <dd>This directory holds the source code for the LLVM assembly language parser
1102 <dt><tt><b>llvm/lib/ByteCode/</b></tt></dt>
1103 <dd>This directory holds code for reading and write LLVM bytecode.</dd>
1105 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1106 different program analyses, such as Dominator Information, Call Graphs,
1107 Induction Variables, Interval Identification, Natural Loop Identification,
1110 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1111 <dd> This directory contains the source code for the LLVM to LLVM program
1112 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1113 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1114 Elimination, and many others.</dd>
1116 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1117 <dd> This directory contains files that describe various target architectures
1118 for code generation. For example, the <tt>llvm/lib/Target/SparcV9</tt>
1119 directory holds the Sparc machine description while
1120 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter</dd>
1122 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1123 <dd> This directory contains the major parts of the code generator: Instruction
1124 Selector, Instruction Scheduling, and Register Allocation.</dd>
1126 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1127 <dd> This directory contains the source level debugger library that makes
1128 it possible to instrument LLVM programs so that a debugger could identify
1129 source code locations at which the program is executing.</dd>
1131 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1132 <dd> This directory contains libraries for executing LLVM bytecode directly
1133 at runtime in both interpreted and JIT compiled fashions.</dd>
1135 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1136 <dd> This directory contains the source code that corresponds to the header
1137 files located in <tt>llvm/include/Support/</tt>.</dd>
1139 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1140 <dd>This directory contains the operating system abstraction layer that
1141 shields LLVM from platform-specific coding.</dd>
1146 <!-- ======================================================================= -->
1147 <div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1148 <div class="doc_text">
1149 <p>This directory contains projects that are not strictly part of LLVM but are
1150 shipped with LLVM. This is also the directory where you should create your own
1151 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1152 to set up your own project. See <tt>llvm/projects/Stacker</tt> for a fully
1153 functional example of a compiler front end.</p>
1156 <!-- ======================================================================= -->
1157 <div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1158 <div class="doc_text">
1160 <p>This directory contains libraries which are compiled into LLVM bytecode and
1161 used when linking programs with the GCC front end. Most of these libraries are
1162 skeleton versions of real libraries; for example, libc is a stripped down
1163 version of glibc.</p>
1165 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1170 <!-- ======================================================================= -->
1171 <div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1172 <div class="doc_text">
1173 <p>This directory contains feature and regression tests and other basic sanity
1174 checks on the LLVM infrastructure. These are intended to run quickly and cover
1175 a lot of territory without being exhaustive.</p>
1178 <!-- ======================================================================= -->
1179 <div class="doc_subsection"><a name="llvmtest"><tt>llvm-test</tt></a></div>
1180 <div class="doc_text">
1181 <p>This is not a directory in the normal llvm module; it is a separate CVS
1182 module that must be checked out (usually to <tt>projects/llvm-test</tt>). This
1183 module contains a comprehensive correctness, performance, and benchmarking
1185 suite for LLVM. It is a separate CVS module because not every LLVM user is
1186 interested in downloading or building such a comprehensive test. For further
1187 details on this test suite, please see the
1188 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1191 <!-- ======================================================================= -->
1192 <div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1193 <div class="doc_text">
1195 <p>The <b>tools</b> directory contains the executables built out of the
1196 libraries above, which form the main part of the user interface. You can
1197 always get help for a tool by typing <tt>tool_name --help</tt>. The
1198 following is a brief introduction to the most important tools. More detailed
1199 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1202 <dt><tt><b>analyze</b></tt></dt>
1203 <dd><tt>analyze</tt> is used to run a specific
1204 analysis on an input LLVM bytecode file and print out the results. It is
1205 primarily useful for debugging analyses, or familiarizing yourself with
1206 what an analysis does.</dd>
1208 <dt><tt><b>bugpoint</b></tt></dt>
1209 <dd><tt>bugpoint</tt> is used to debug
1210 optimization passes or code generation backends by narrowing down the
1211 given test case to the minimum number of passes and/or instructions that
1212 still cause a problem, whether it is a crash or miscompilation. See <a
1213 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1214 on using <tt>bugpoint</tt>.</dd>
1216 <dt><tt><b>llvmc</b></tt></dt>
1217 <dd>The LLVM Compiler Driver. This program can
1218 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1219 pre-processing, translation, optimization, assembly, and linking of programs
1220 all from one command line. <tt>llvmc</tt> also takes care of processing the
1221 dependent libraries found in bytecode. This reduces the need to get the
1222 traditional <tt>-l<name></tt> options right on the command line. Please
1223 note that this tool is new in 1.4 and considered experimental. It will be
1224 fully supported in 1.5.</dd>
1226 <dt><tt><b>llvm-ar</b></tt></dt>
1227 <dd>The archiver produces an archive containing
1228 the given LLVM bytecode files, optionally with an index for faster
1231 <dt><tt><b>llvm-as</b></tt></dt>
1232 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1235 <dt><tt><b>llvm-dis</b></tt></dt>
1236 <dd>The disassembler transforms the LLVM bytecode to human readable
1239 <dt><tt><b>llvm-ld</b></tt></dt>
1240 <dd><tt>llvm-ld</tt> is very similar to gccld and provides a general purpose
1241 and extensible linker for LLVM. This is the linker invoked by <tt>llvmc</tt>.
1242 It allows optimization modules to be loaded so that language specific
1243 optimizations can be applied at link time. Please note that this tool is new
1244 in LLVM 1.4 and still considered experimental. It will be fully supported in
1247 <dt><tt><b>llvm-link</b></tt></dt>
1248 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1249 a single program.</dd>
1251 <dt><tt><b>lli</b></tt></dt>
1252 <dd><tt>lli</tt> is the LLVM interpreter, which
1253 can directly execute LLVM bytecode (although very slowly...). In addition
1254 to a simple interpreter, <tt>lli</tt> also has a tracing mode (entered by
1255 specifying <tt>-trace</tt> on the command line). Finally, for
1256 architectures that support it (currently x86, Sparc, and PowerPC), by default,
1257 <tt>lli</tt> will function as a Just-In-Time compiler (if the
1258 functionality was compiled in), and will execute the code <i>much</i>
1259 faster than the interpreter.</dd>
1261 <dt><tt><b>llc</b></tt></dt>
1262 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1263 translates LLVM bytecode to a SPARC or x86 assembly file, or to C code (with
1264 the -march=c option).</dd>
1266 <dt><tt><b>llvmgcc</b></tt></dt>
1267 <dd><tt>llvmgcc</tt> is a GCC-based C frontend
1268 that has been retargeted to emit LLVM code as the machine code output. It
1269 works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
1270 -o</tt> options that are typically used. The source code for the
1271 <tt>llvmgcc</tt> tool is currently not included in the LLVM CVS tree
1272 because it is quite large and not very interesting.
1275 <dt><tt><b>gccas</b></tt></dt>
1276 <dd>This tool is invoked by the <tt>llvmgcc</tt> frontend as the
1277 "assembler" part of the compiler. This tool actually assembles LLVM
1278 assembly to LLVM bytecode, performs a variety of optimizations, and
1279 outputs LLVM bytecode. Thus when you invoke
1280 <tt>llvmgcc -c x.c -o x.o</tt>, you are causing <tt>gccas</tt> to be
1281 run, which writes the <tt>x.o</tt> file (which is an LLVM bytecode file
1282 that can be disassembled or manipulated just like any other bytecode
1283 file). The command line interface to <tt>gccas</tt> is designed to be
1284 as close as possible to the <b>system</b> `<tt>as</tt>' utility so that
1285 the gcc frontend itself did not have to be modified to interface to
1286 a "weird" assembler.</dd>
1288 <dt><tt><b>gccld</b></tt></dt>
1289 <dd><tt>gccld</tt> links together several LLVM bytecode files into one
1290 bytecode file and does some optimization. It is the linker invoked by
1291 the GCC frontend when multiple .o files need to be linked together.
1292 Like <tt>gccas</tt>, the command line interface of <tt>gccld</tt> is
1293 designed to match the system linker, to aid interfacing with the GCC
1299 <dt><tt><b>opt</b></tt></dt>
1300 <dd><tt>opt</tt> reads LLVM bytecode, applies a
1301 series of LLVM to LLVM transformations (which are specified on the command
1302 line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
1303 command is a good way to get a list of the program transformations
1304 available in LLVM.</dd>
1308 <!-- ======================================================================= -->
1309 <div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1310 <div class="doc_text">
1312 <p>This directory contains utilities for working with LLVM source code, and some
1313 of the utilities are actually required as part of the build process because they
1314 are code generators for parts of LLVM infrastructure.</p>
1317 <dt><tt><b>Burg/</b></tt> <dd><tt>Burg</tt> is an instruction selector
1318 generator -- it builds trees on which it then performs pattern-matching to
1319 select instructions according to the patterns the user has specified. Burg
1320 is currently used in the Sparc V9 backend.<p>
1322 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1323 that finds differences between code that LLC generates and code that LLI
1324 generates. This is a useful tool if you are debugging one of them,
1325 assuming that the other generates correct output. For the full user
1326 manual, run <tt>`perldoc codegen-diff'</tt>.<p>
1328 <dt><tt><b>cvsupdate</b></tt> <dd><tt>cvsupdate</tt> is a script that will
1329 update your CVS tree, but produce a much cleaner and more organized output
1330 than simply running <tt>`cvs -z3 up -dP'</tt> will. For example, it will group
1331 together all the new and updated files and modified files in separate
1332 sections, so you can see at a glance what has changed. If you are at the
1333 top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
1334 preferred way of updating the tree.<p>
1336 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1337 syntax-highlighting files which will work with Emacs and XEmacs editors,
1338 providing syntax highlighting support for LLVM assembly files and TableGen
1339 description files. For information on how to use the syntax files, consult
1340 the <tt>README</tt> file in that directory.<p>
1342 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1343 and outputs all non-generated source files, which is useful if one wishes
1344 to do a lot of development across directories and does not want to
1345 individually find each file. One way to use it is to run, for example:
1346 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1349 <dt><tt><b>llvmgrep</b></tt></dt>
1350 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1351 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1352 line. This is a very efficient way of searching the source base for a
1353 particular regular expression.</dd>
1355 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1356 files in the current directory and then compiles and links the tool that
1357 is the first argument. For example, assuming you are in the directory
1358 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1359 simply running <tt>makellvm llc</tt> will make a build of the current
1360 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1361 causing a re-linking of LLC.<p>
1363 <dt><tt><b>NightlyTest.pl</b></tt> and
1364 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1365 cron script to generate nightly status reports of the functionality of
1366 tools, and the results can be seen by following the appropriate link on
1367 the <a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a>.<p>
1369 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1370 the tool used to generate register descriptions, instruction set
1371 descriptions, and even assemblers from common TableGen description
1374 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1375 syntax-highlighting files which will work with the VIM editor, providing
1376 syntax highlighting support for LLVM assembly files and TableGen
1377 description files. For information on how to use the syntax files, consult
1378 the <tt>README</tt> file in that directory.<p>
1384 <!-- ======================================================================= -->
1385 <div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1386 <div class="doc_text">
1387 <p>This directory contains build scripts and project files for use with
1388 Visual C++. This allows developers on Windows to build LLVM without the need
1389 for Cygwin. The contents of this directory should be considered experimental
1393 <!-- *********************************************************************** -->
1394 <div class="doc_section">
1395 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1397 <!-- *********************************************************************** -->
1399 <div class="doc_text">
1402 <li>First, create a simple C file, name it 'hello.c':
1404 #include <stdio.h>
1406 printf("hello world\n");
1411 <li><p>Next, compile the C file into a LLVM bytecode file:</p>
1412 <p><tt>% llvmgcc hello.c -o hello</tt></p>
1414 <p>Note that you should have already built the tools and they have to be
1415 in your path, at least <tt>gccas</tt> and <tt>gccld</tt>.</p>
1417 <p>This will create two result files: <tt>hello</tt> and
1418 <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
1419 corresponds the the compiled program and the library facilities that it
1420 required. <tt>hello</tt> is a simple shell script that runs the bytecode
1421 file with <tt>lli</tt>, making the result directly executable. Note that
1422 all LLVM optimizations are enabled by default, so there is no need for a
1423 "-O3" switch.</p></li>
1425 <li><p>Run the program. To make sure the program ran, execute one of the
1426 following commands:</p>
1428 <p><tt>% ./hello</tt></p>
1432 <p><tt>% lli hello.bc</tt></p></li>
1434 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1437 <p><tt>% llvm-dis < hello.bc | less</tt><p></li>
1439 <li><p>Compile the program to native assembly using the LLC code
1442 <p><tt>% llc hello.bc -o hello.s</tt></p>
1444 <li><p>Assemble the native assembly language file into a program:</p>
1446 <p><b>Solaris:</b><tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native</tt></p>
1447 <p><b>Others:</b><tt>% gcc hello.s -o hello.native</tt></p>
1449 <li><p>Execute the native code program:</p>
1451 <p><tt>% ./hello.native</tt></p></li>
1457 <!-- *********************************************************************** -->
1458 <div class="doc_section">
1459 <a name="problems">Common Problems</a>
1461 <!-- *********************************************************************** -->
1463 <div class="doc_text">
1465 <p>If you are having problems building or using LLVM, or if you have any other
1466 general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1467 Asked Questions</a> page.</p>
1471 <!-- *********************************************************************** -->
1472 <div class="doc_section">
1473 <a name="links">Links</a>
1475 <!-- *********************************************************************** -->
1477 <div class="doc_text">
1479 <p>This document is just an <b>introduction</b> to how to use LLVM to do
1480 some simple things... there are many more interesting and complicated things
1481 that you can do that aren't documented here (but we'll gladly accept a patch
1482 if you want to write something up!). For more information about LLVM, check
1486 <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
1487 <li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
1488 <li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project
1489 that Uses LLVM</a></li>
1494 <!-- *********************************************************************** -->
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1503 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1504 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1505 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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