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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></li>
117 <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf -</tt>
119 <li><tt>cd cfrontend/<i>platform</i><br>
120 ./fixheaders</tt></li>
121 <li>Add the cfrontend's "bin" directory to your PATH variable</li>
124 <li>Get the Source Code
126 <li>With the distributed files:
128 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
129 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
130 <li><tt>cd llvm</tt></li>
133 <li>With anonymous CVS access (or use a <a href="#mirror">mirror</a>):
135 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
137 :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt></li>
138 <li>Hit the return key when prompted for the password.
139 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm
141 <li><tt>cd llvm</tt></li>
142 <li><tt>cvs up -P -d</tt></li>
146 <li>Get the Test Suite Source Code (<em>optional</em>)
148 <li>With the distributed files:
150 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
151 <li><tt>cd llvm/projects</tt>
152 <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
153 <li><tt>cd ..</tt></li>
156 <li>With anonymous CVS access (or use a <a href="#mirror">mirror</a>):
158 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
159 <li><tt>cd llvm/projects</tt>
161 :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt></li>
162 <li>Hit the return key when prompted for the password.
163 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm
164 co llvm-test</tt></li>
165 <li><tt>cd llvm-test</tt></li>
166 <li><tt>cvs up -P -d</tt></li>
167 <li><tt>cd ..</tt></li>
172 <li>Configure the LLVM Build Environment
174 <li>Change directory to where you want to store the LLVM object
175 files and run <tt>configure</tt> to configure the Makefiles and
176 header files for the default platform. Useful options include:
178 <li><tt>--prefix=<i>directory</i></tt>
179 <p>Specify for <i>directory</i> the full pathname of where you
180 want the LLVM tools and libraries to be installed.</p></li>
181 <li><tt>--enable-spec2000=<i>directory</i></tt>
182 <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
183 benchmarks should be available in
184 <tt><i>directory</i></tt>.</p></li>
188 <li>Build the LLVM Suite:
190 <li><tt>gmake -k |& tee gnumake.out
191 # this is csh or tcsh syntax</tt></li>
192 <li>If you get an "internal compiler error (ICE)" see <a href="#brokengcc">below</a>.</li>
197 <p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
198 detailed information on configuring and compiling LLVM. See <a
199 href="#environment">Setting Up Your Environment</a> for tips that simplify
200 working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
201 Layout</a> to learn about the layout of the source code tree.</p>
205 <!-- *********************************************************************** -->
206 <div class="doc_section">
207 <a name="requirements"><b>Requirements</b></a>
209 <!-- *********************************************************************** -->
211 <div class="doc_text">
213 <p>Before you begin to use the LLVM system, review the requirements given below.
214 This may save you some trouble by knowing ahead of time what hardware and
215 software you will need.</p>
219 <!-- ======================================================================= -->
220 <div class="doc_subsection">
221 <a name="hardware"><b>Hardware</b></a>
224 <div class="doc_text">
226 <p>LLVM is known to work on the following platforms:</p>
228 <table cellpadding="3">
236 <td>x86<sup>1</sup></td>
241 <td>V9 (Ultrasparc)</td>
246 <td>x86<sup>1</sup></td>
250 <td>MacOS X<sup>2</sup></td>
255 <td>Cygwin/Win32</td>
256 <td>x86<sup>1</sup></td>
257 <td>GCC 3.4.X, binutils 2.15</td>
261 <td>amd64<sup>3</sup></td>
266 <p>LLVM has partial support for the following platforms:</p>
276 <td>x86<sup>1</sup></td>
277 <td>Visual Studio .NET<sup>4,5</sup>, MinGW</td>
279 <td>AIX<sup>3,4</sup></td>
284 <td>Linux<sup>3,5</sup></td>
292 <sup>1</sup> Code generation supported for Pentium processors and up<br>
293 <sup>2</sup> Code generation supported for 32-bit ABI only<br>
294 <sup>3</sup> No native code generation<br>
295 <sup>4</sup> Build is not complete: one or more tools don't link<br>
296 <sup>5</sup> The GCC-based C/C++ frontend does not build<br>
299 <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
300 mode, depending on the system (because of all the debug info), and the libraries
301 appear in more than one of the tools that get linked, so there is some
302 duplication. If you do not need many of the tools and you are space-conscious,
303 you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
304 build requires considerably less space.</p>
306 <p>The LLVM suite <i>may</i> compile on other platforms, but it is not
307 guaranteed to do so. If compilation is successful, the LLVM utilities should be
308 able to assemble, disassemble, analyze, and optimize LLVM bytecode. Code
309 generation should work as well, although the generated native code may not work
310 on your platform.</p>
312 <p>The GCC front end is not very portable at the moment. If you want to get it
313 to work on another platform, you can download a copy of the source and <a
314 href="CFEBuildInstrs.html">try to compile it</a> on your platform.</p>
318 <!-- ======================================================================= -->
319 <div class="doc_subsection"><a name="software"><b>Software</b></a></div>
320 <div class="doc_text">
321 <p>Compiling LLVM requires that you have several software packages
322 installed. The table below lists those required packages. The Package column
323 is the usual name for the software package that LLVM depends on. The Version
324 column provides "known to work" versions of the package. The Notes column
325 describes how LLVM uses the package and provides other details.</p>
327 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
330 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
331 <td>3.79, 3.79.1</td>
332 <td>Makefile/build processor</td>
336 <td><a href="http://gcc.gnu.org">GCC</a></td>
338 <td>C/C++ compiler (<a href="#Note3">Note 3</a>)</td>
342 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
344 <td>LEX compiler</td>
348 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
350 <td>YACC compiler</td>
354 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
356 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
360 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
362 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
366 <td><a href="http://expect.nist.gov/">expect</a></td>
368 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
372 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
374 <td>Macro processor for configuration (<a href="#Note1">Note 1</a>)</td>
378 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
380 <td>Configuration script builder (<a href="#Note1">Note 1</a>)</td>
384 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
386 <td>aclocal macro generator (<a href="#Note1">Note 1</a>)</td>
390 <td><a href="http://www.perl.com/download.csp">perl</a></td>
392 <td>Nightly tester, utilities</td>
396 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
398 <td>Shared library manager (<a href="#Note1">Note 1</a>)</td>
402 <td><a href="https://www.cvshome.org/downloads.html">CVS</a></td>
404 <td>CVS access to LLVM (<a href="#Note4">Note 4</a>)</td>
411 <li><a name="Note1">If you want to make changes to the configure scripts,
412 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
413 or higher). You will also need automake (1.9.2). We only use aclocal
414 from that package.</a></li>
415 <li><a name="Note2">Only needed if you want to run the automated test
416 suite in the <tt>test</tt> directory.</a></li>
418 <li><a name="Note3">Only the C and C++ languages are needed so there's no
419 need to build the other languages for LLVM's purposes.</a> See
420 <a href="#brokengcc">below</a> for specific version info.
422 <li><a name="Note4">You only need CVS if you intend to build from the
423 latest LLVM sources. If you're working from a release distribution, you
424 don't need CVS.</a></li>
426 <p>Additionally, your compilation host is expected to have the usual
427 plethora of Unix utilities. Specifically:</p>
429 <li><b>ar</b> - archive library builder</li>
430 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
431 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
432 <li><b>chmod</b> - change permissions on a file</li>
433 <li><b>cat</b> - output concatenation utility</li>
434 <li><b>cp</b> - copy files</li>
435 <li><b>date</b> - print the current date/time </li>
436 <li><b>echo</b> - print to standard output</li>
437 <li><b>egrep</b> - extended regular expression search utility</li>
438 <li><b>etags</b> - C/C++ tag file creator for vim/emacs</li>
439 <li><b>find</b> - find files/dirs in a file system</li>
440 <li><b>grep</b> - regular expression search utility</li>
441 <li><b>gzip*</b> - gzip command for distribution generation</li>
442 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
443 <li><b>install</b> - install directories/files </li>
444 <li><b>mkdir</b> - create a directory</li>
445 <li><b>mv</b> - move (rename) files</li>
446 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
447 <li><b>rm</b> - remove (delete) files and directories</li>
448 <li><b>sed</b> - stream editor for transforming output</li>
449 <li><b>sh</b> - Bourne shell for make build scripts</li>
450 <li><b>tar</b> - tape archive for distribution generation</li>
451 <li><b>test</b> - test things in file system</li>
452 <li><b>unzip*</b> - unzip command for distribution checking</li>
453 <li><b>zip*</b> - zip command for distribution generation</li>
457 <!-- ======================================================================= -->
458 <div class="doc_subsection">
459 <a name="brokengcc">Broken versions of GCC</a>
462 <div class="doc_text">
464 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
465 bugs in the compiler. In particular, several versions of GCC crash when trying
466 to compile LLVM. We routinely use GCC 3.3.3 and GCC 3.4.0 and have had success
467 with them. Other versions of GCC will probably work as well. GCC versions listed
468 here are known to not work. If you are using one of these versions, please try
469 to upgrade your GCC to something more recent. If you run into a problem with a
470 version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
471 us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
472 of GCC you are using.
475 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
476 problems in the STL that effectively prevent it from compiling LLVM.
479 <p><b>GCC 3.2.2</b>: This version of GCC fails to compile LLVM.</p>
481 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
482 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
483 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
488 <!-- *********************************************************************** -->
489 <div class="doc_section">
490 <a name="starting"><b>Getting Started with LLVM</b></a>
492 <!-- *********************************************************************** -->
494 <div class="doc_text">
496 <p>The remainder of this guide is meant to get you up and running with
497 LLVM and to give you some basic information about the LLVM environment.</p>
499 <p>The later sections of this guide describe the <a
500 href="#layout">general layout</a> of the the LLVM source tree, a <a
501 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
502 href="#links">links</a> to find more information about LLVM or to get
506 <!-- ======================================================================= -->
507 <div class="doc_subsection">
508 <a name="terminology">Terminology and Notation</a>
511 <div class="doc_text">
513 <p>Throughout this manual, the following names are used to denote paths
514 specific to the local system and working environment. <i>These are not
515 environment variables you need to set but just strings used in the rest
516 of this document below</i>. In any of the examples below, simply replace
517 each of these names with the appropriate pathname on your local system.
518 All these paths are absolute:</p>
523 This is the top level directory of the LLVM source tree.
528 This is the top level directory of the LLVM object tree (i.e. the
529 tree where object files and compiled programs will be placed. It
530 can be the same as SRC_ROOT).
535 This is the where the LLVM GCC Front End is installed.
537 For the pre-built GCC front end binaries, the LLVMGCCDIR is
538 <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
543 <!-- ======================================================================= -->
544 <div class="doc_subsection">
545 <a name="environment">Setting Up Your Environment</a>
548 <div class="doc_text">
551 In order to compile and use LLVM, you will need to set some environment
552 variables. There are also some shell aliases which you may find useful.
553 You can set these on the command line, or better yet, set them in your
554 <tt>.cshrc</tt> or <tt>.profile</tt>.
557 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bytecode/libs</tt></dt>
558 <dd>This environment variable helps LLVM linking tools find the locations
559 of your bytecode libraries. It is optional and provided only a convenience
560 since you can specify the paths using the -L options of the tools.</dd>
562 <dt><tt>alias llvmgcc='llvm-gcc'</tt></dt>
563 <dt><tt>alias llvmg++='llvm-g++'</tt></dt>
564 <dd></dt>These aliases allow you to use the LLVM C and C++ front ends
565 under alternative names. It is assumed that llvm-gcc and llvm-g++ are
566 in your path. The LLVM makefiles will use llvm-gcc and llvm-g++ directly.</dd>
571 <!-- ======================================================================= -->
572 <div class="doc_subsection">
573 <a name="unpack">Unpacking the LLVM Archives</a>
576 <div class="doc_text">
579 If you have the LLVM distribution, you will need to unpack it before you
580 can begin to compile it. LLVM is distributed as a set of two files: the LLVM
581 suite and the LLVM GCC front end compiled for your platform. There is an
582 additional test suite that is optional. Each file is a TAR archive that is
583 compressed with the gzip program.
586 <p> The files are as follows:
588 <dt><tt>llvm-1.4.tar.gz</tt></dt>
589 <dd>This is the source code for the LLVM libraries and tools.<br/></dd>
591 <dt><tt>llvm-test-1.4.tar.gz</tt></dt>
592 <dd>This is the source code for the LLVM test suite.</tt></dd>
594 <dt><tt>cfrontend-1.4.source.tar.gz</tt></dt>
595 <dd>This is the source release of the GCC front end.<br/></dd>
597 <dt><tt>cfrontend-1.4.sparc-sun-solaris2.8.tar.gz</tt></dt>
598 <dd>This is the binary release of the GCC front end for Solaris/Sparc.
601 <dt><tt>cfrontend-1.4.i686-redhat-linux-gnu.tar.gz</tt></dt>
602 <dd>This is the binary release of the GCC front end for Linux/x86.<br/></dd>
604 <dt><tt>cfrontend-1.4.i386-unknown-freebsd5.1.tar.gz</tt></dt>
605 <dd>This is the binary release of the GCC front end for FreeBSD/x86.<br/></dd>
607 <dt><tt>cfrontend-1.4.powerpc-apple-darwin7.6.0.tar.gz</tt></dt>
608 <dd>This is the binary release of the GCC front end for MacOS X/PPC.<br/></dd>
613 <!-- ======================================================================= -->
614 <div class="doc_subsection">
615 <a name="checkout">Checkout LLVM from CVS</a>
618 <div class="doc_text">
620 <p>If you have access to our CVS repository, you can get a fresh copy of
621 the entire source code. All you need to do is check it out from CVS as
625 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
626 <li><tt>cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
627 <li>Hit the return key when prompted for the password.
628 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co
632 <p>This will create an '<tt>llvm</tt>' directory in the current
633 directory and fully populate it with the LLVM source code, Makefiles,
634 test directories, and local copies of documentation files.</p>
636 <p>If you want to get a specific release (as opposed to the most recent
637 revision), you can specify a label. The following releases have the following
641 <li>Release 1.4: <b>RELEASE_14</b></li>
642 <li>Release 1.3: <b>RELEASE_13</b></li>
643 <li>Release 1.2: <b>RELEASE_12</b></li>
644 <li>Release 1.1: <b>RELEASE_11</b></li>
645 <li>Release 1.0: <b>RELEASE_1</b></li>
648 <p>If you would like to get the LLVM test suite (a separate package as of 1.4),
649 you get it from the CVS repository:</p>
652 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-test
654 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
655 configured by the LLVM configure script as well as automatically updated when
656 you run <tt>cvs update</tt>.</p>
658 <p>If you would like to get the GCC front end source code, you can also get it
659 from the CVS repository:</p>
662 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-gcc
665 <p>Please note that you must follow <a href="CFEBuildInstrs.html">these
666 instructions</a> to successfully build the LLVM GCC front-end.</p>
670 <!-- ======================================================================= -->
671 <div class="doc_subsubsection">
672 <a name="mirrors">LLVM CVS Mirrors</a>
675 <div class="doc_text">
677 <p>If the main CVS server is overloaded or inaccessible, you can try one of
678 these user-hosted mirrors:</p>
681 <li><a href="http://llvm.x10sys.com/">Mirror hosted by eXtensible Systems
686 <!-- ======================================================================= -->
687 <div class="doc_subsection">
688 <a name="installcf">Install the GCC Front End</a>
691 <div class="doc_text">
693 <p>Before configuring and compiling the LLVM suite, you need to extract the LLVM
694 GCC front end from the binary distribution. It is used for building the
695 bytecode libraries later used by the GCC front end for linking programs, and its
696 location must be specified when the LLVM suite is configured.</p>
698 <p>To install the GCC front end, do the following:</p>
701 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
702 <li><tt>gunzip --stdout cfrontend-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
706 <p>Next, you will need to fix your system header files:</p>
708 <p><tt>cd cfrontend/<i>platform</i><br>
709 ./fixheaders</tt></p>
711 <p>The binary versions of the GCC front end may not suit all of your needs. For
712 example, the binary distribution may include an old version of a system header
713 file, not "fix" a header file that needs to be fixed for GCC, or it may be
714 linked with libraries not available on your system.</p>
716 <p>In cases like these, you may want to try <a
717 href="CFEBuildInstrs.html">building the GCC front end from source.</a> This is
718 not for the faint of heart, so be forewarned.</p>
722 <!-- ======================================================================= -->
723 <div class="doc_subsection">
724 <a name="config">Local LLVM Configuration</a>
727 <div class="doc_text">
729 <p>Once checked out from the CVS repository, the LLVM suite source code must be
730 configured via the <tt>configure</tt> script. This script sets variables in the
731 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
732 <tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
733 the Makefiles needed to begin building LLVM.</p>
735 <p>The following environment variables are used by the <tt>configure</tt>
736 script to configure the build system:</p>
739 <tr><th>Variable</th><th>Purpose</th></tr>
742 <td>Tells <tt>configure</tt> which C compiler to use. By default,
743 <tt>configure</tt> will look for the first GCC C compiler in
744 <tt>PATH</tt>. Use this variable to override
745 <tt>configure</tt>'s default behavior.</td>
749 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
750 <tt>configure</tt> will look for the first GCC C++ compiler in
751 <tt>PATH</tt>. Use this variable to override
752 <tt>configure</tt>'s default behavior.</td>
756 <p>The following options can be used to set or enable LLVM specific options:</p>
759 <dt><i>--with-tclinclude</i></dt>
760 <dd>Path to the tcl include directory under which the <tt>tclsh</tt> can be
761 found. Use this if you have multiple tcl installations on your machine and you
762 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
763 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
764 option, the LLVM configure script will search for tcl 8.4 and 8.3 releases.
767 <dt><i>--enable-optimized</i></dt>
769 Enables optimized compilation by default (debugging symbols are removed
770 and GCC optimization flags are enabled). The default is to use an
771 unoptimized build (also known as a debug build).
774 <dt><i>--enable-jit</i></dt>
776 Compile the Just In Time (JIT) compiler functionality. This is not
778 on all platforms. The default is dependent on platform, so it is best
779 to explicitly enable it if you want it.
782 <dt><i>--enable-doxygen</i></dt>
783 <dd>Look for the doxygen program and enable construction of doxygen based
784 documentation from the source code. This is disabled by default because
785 generating the documentation can take a long time and producess 100s of
786 megabytes of output.</dd>
789 <p>To configure LLVM, follow these steps:</p>
792 <li>Change directory into the object root directory:
794 <tt>cd <i>OBJ_ROOT</i></tt>
797 <li>Run the <tt>configure</tt> script located in the LLVM source tree:
799 <tt><i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</tt>
805 <!-- ======================================================================= -->
806 <div class="doc_subsection">
807 <a name="compile">Compiling the LLVM Suite Source Code</a>
810 <div class="doc_text">
812 <p>Once you have configured LLVM, you can build it. There are three types of
818 These builds are the default when one types <tt>gmake</tt> (unless the
819 <tt>--enable-optimized</tt> option was used during configuration). The
820 build system will compile the tools and libraries with debugging
824 <dt>Release (Optimized) Builds
826 These builds are enabled with the <tt>--enable-optimized</tt> option to
827 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
828 <tt>gmake</tt> command line. For these builds, the build system will
829 compile the tools and libraries with GCC optimizations enabled and strip
830 debugging information from the libraries and executables it generates.
835 These builds are for use with profiling. They compile profiling
836 information into the code for use with programs like <tt>gprof</tt>.
837 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
838 on the <tt>gmake</tt> command line.
841 <p>Once you have LLVM configured, you can build it by entering the
842 <i>OBJ_ROOT</i> directory and issuing the following command:</p>
844 <p><tt>gmake</tt></p>
846 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
847 are using a version of GCC that is known not to compile LLVM.</p>
850 If you have multiple processors in your machine, you may wish to use some of
851 the parallel build options provided by GNU Make. For example, you could use the
854 <p><tt>gmake -j2</tt></p>
856 <p>There are several special targets which are useful when working with the LLVM
860 <dt><tt>gmake clean</tt>
862 Removes all files generated by the build. This includes object files,
863 generated C/C++ files, libraries, and executables.
866 <dt><tt>gmake dist-clean</tt>
868 Removes everything that <tt>gmake clean</tt> does, but also removes files
869 generated by <tt>configure</tt>. It attempts to return the source tree to the
870 original state in which it was shipped.
873 <dt><tt>gmake install</tt>
875 Installs LLVM header files, libraries, tools, and documentation in a
877 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
878 defaults to <tt>/usr/local</tt>.
881 <dt><tt>gmake -C runtime install-bytecode</tt>
883 Assuming you built LLVM into $OBJDIR, when this command is run, it will
884 install bytecode libraries into the GCC front end's bytecode library
885 directory. If you need to update your bytecode libraries,
886 this is the target to use once you've built them.
890 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
891 details on these <tt>make</tt> targets and descriptions of other targets
894 <p>It is also possible to override default values from <tt>configure</tt> by
895 declaring variables on the command line. The following are some examples:</p>
898 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
900 Perform a Release (Optimized) build.
903 <dt><tt>gmake ENABLE_PROFILING=1</tt>
905 Perform a Profiling build.
908 <dt><tt>gmake VERBOSE=1</tt>
910 Print what <tt>gmake</tt> is doing on standard output.
913 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
914 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
915 the standard output. This also implies <tt>VERBOSE=1</tt>.
919 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
920 it and any subdirectories that it contains. Entering any directory inside the
921 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
922 that directory that is out of date.</p>
926 <!-- ======================================================================= -->
927 <div class="doc_subsection">
928 <a name="objfiles">The Location of LLVM Object Files</a>
931 <div class="doc_text">
933 <p>The LLVM build system is capable of sharing a single LLVM source tree among
934 several LLVM builds. Hence, it is possible to build LLVM for several different
935 platforms or configurations using the same source tree.</p>
937 <p>This is accomplished in the typical autoconf manner:</p>
940 <li><p>Change directory to where the LLVM object files should live:</p>
942 <p><tt>cd <i>OBJ_ROOT</i></tt></p></li>
944 <li><p>Run the <tt>configure</tt> script found in the LLVM source
947 <p><tt><i>SRC_ROOT</i>/configure</tt></p></li>
950 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
951 named after the build type:</p>
958 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
960 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
968 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
970 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
978 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
980 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
986 <!-- ======================================================================= -->
987 <div class="doc_subsection">
988 <a name="optionalconfig">Optional Configuration Items</a>
991 <div class="doc_text">
994 If you're running on a linux system that supports the "<a
995 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">
997 module, and you have root access on the system, you can set your system up to
998 execute LLVM bytecode files directly. To do this, use commands like this (the
999 first command may not be required if you are already using the module):</p>
1002 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1003 $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
1004 $ chmod u+x hello.bc (if needed)
1009 This allows you to execute LLVM bytecode files directly. Thanks to Jack
1010 Cummings for pointing this out!
1016 <!-- *********************************************************************** -->
1017 <div class="doc_section">
1018 <a name="layout"><b>Program Layout</b></a>
1020 <!-- *********************************************************************** -->
1022 <div class="doc_text">
1024 <p>One useful source of information about the LLVM source base is the LLVM <a
1025 href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1026 href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>.
1027 The following is a brief introduction to code layout:</p>
1031 <!-- ======================================================================= -->
1032 <div class="doc_subsection"><a name="cvsdir"><tt>CVS</tt> directories</a></div>
1033 <div class="doc_text">
1034 <p>Every directory checked out of CVS will contain a <tt>CVS</tt> directory; for
1035 the most part these can just be ignored.</p>
1038 <!-- ======================================================================= -->
1039 <div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1040 <div class="doc_text">
1041 <p>This directory contains some simple examples of how to use the LLVM IR and
1045 <!-- ======================================================================= -->
1046 <div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1047 <div class="doc_text">
1049 <p>This directory contains public header files exported from the LLVM
1050 library. The three main subdirectories of this directory are:</p>
1053 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1054 <dd>This directory contains all of the LLVM specific header files. This
1055 directory also has subdirectories for different portions of LLVM:
1056 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1059 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1060 <dd>This directory contains generic support libraries that are provided with
1061 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1062 and a Command Line option processing library store their header files here.
1065 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1066 <dd>This directory contains header files configured by the <tt>configure</tt>
1067 script. They wrap "standard" UNIX and C header files. Source code can
1068 include these header files which automatically take care of the conditional
1069 #includes that the <tt>configure</tt> script generates.</dd>
1073 <!-- ======================================================================= -->
1074 <div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1075 <div class="doc_text">
1077 <p>This directory contains most of the source files of the LLVM system. In LLVM,
1078 almost all code exists in libraries, making it very easy to share code among the
1079 different <a href="#tools">tools</a>.</p>
1082 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1083 <dd> This directory holds the core LLVM source files that implement core
1084 classes like Instruction and BasicBlock.</dd>
1086 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1087 <dd>This directory holds the source code for the LLVM assembly language parser
1090 <dt><tt><b>llvm/lib/ByteCode/</b></tt></dt>
1091 <dd>This directory holds code for reading and write LLVM bytecode.</dd>
1093 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1094 different program analyses, such as Dominator Information, Call Graphs,
1095 Induction Variables, Interval Identification, Natural Loop Identification,
1098 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1099 <dd> This directory contains the source code for the LLVM to LLVM program
1100 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1101 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1102 Elimination, and many others.</dd>
1104 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1105 <dd> This directory contains files that describe various target architectures
1106 for code generation. For example, the <tt>llvm/lib/Target/SparcV9</tt>
1107 directory holds the Sparc machine description while
1108 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter</dd>
1110 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1111 <dd> This directory contains the major parts of the code generator: Instruction
1112 Selector, Instruction Scheduling, and Register Allocation.</dd>
1114 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1115 <dd> This directory contains the source level debugger library that makes
1116 it possible to instrument LLVM programs so that a debugger could identify
1117 source code locations at which the program is executing.</dd>
1119 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1120 <dd> This directory contains libraries for executing LLVM bytecode directly
1121 at runtime in both interpreted and JIT compiled fashions.</dd>
1123 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1124 <dd> This directory contains the source code that corresponds to the header
1125 files located in <tt>llvm/include/Support/</tt>.</dd>
1127 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1128 <dd>This directory contains the operating system abstraction layer that
1129 shields LLVM from platform-specific coding.</dd>
1134 <!-- ======================================================================= -->
1135 <div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1136 <div class="doc_text">
1137 <p>This directory contains projects that are not strictly part of LLVM but are
1138 shipped with LLVM. This is also the directory where you should create your own
1139 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1140 to set up your own project. See <tt>llvm/projects/Stacker</tt> for a fully
1141 functional example of a compiler front end.</p>
1144 <!-- ======================================================================= -->
1145 <div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1146 <div class="doc_text">
1148 <p>This directory contains libraries which are compiled into LLVM bytecode and
1149 used when linking programs with the GCC front end. Most of these libraries are
1150 skeleton versions of real libraries; for example, libc is a stripped down
1151 version of glibc.</p>
1153 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1158 <!-- ======================================================================= -->
1159 <div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1160 <div class="doc_text">
1161 <p>This directory contains feature and regression tests and other basic sanity
1162 checks on the LLVM infrastructure. These are intended to run quickly and cover
1163 a lot of territory without being exhaustive.</p>
1166 <!-- ======================================================================= -->
1167 <div class="doc_subsection"><a name="llvmtest"><tt>llvm-test</tt></a></div>
1168 <div class="doc_text">
1169 <p>This is not a directory in the normal llvm module; it is a separate CVS
1170 module that must be checked out (usually to <tt>projects/llvm-test</tt>). This
1171 module contains a comprehensive correctness, performance, and benchmarking
1173 suite for LLVM. It is a separate CVS module because not every LLVM user is
1174 interested in downloading or building such a comprehensive test. For further
1175 details on this test suite, please see the
1176 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1179 <!-- ======================================================================= -->
1180 <div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1181 <div class="doc_text">
1183 <p>The <b>tools</b> directory contains the executables built out of the
1184 libraries above, which form the main part of the user interface. You can
1185 always get help for a tool by typing <tt>tool_name --help</tt>. The
1186 following is a brief introduction to the most important tools. More detailed
1187 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1190 <dt><tt><b>analyze</b></tt></dt>
1191 <dd><tt>analyze</tt> is used to run a specific
1192 analysis on an input LLVM bytecode file and print out the results. It is
1193 primarily useful for debugging analyses, or familiarizing yourself with
1194 what an analysis does.</dd>
1196 <dt><tt><b>bugpoint</b></tt></dt>
1197 <dd><tt>bugpoint</tt> is used to debug
1198 optimization passes or code generation backends by narrowing down the
1199 given test case to the minimum number of passes and/or instructions that
1200 still cause a problem, whether it is a crash or miscompilation. See <a
1201 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1202 on using <tt>bugpoint</tt>.</dd>
1204 <dt><tt><b>llvmc</b></tt></dt>
1205 <dd>The LLVM Compiler Driver. This program can
1206 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1207 pre-processing, translation, optimization, assembly, and linking of programs
1208 all from one command line. <tt>llvmc</tt> also takes care of processing the
1209 dependent libraries found in bytecode. This reduces the need to get the
1210 traditional <tt>-l<name></tt> options right on the command line. Please
1211 note that this tool is new in 1.4 and considered experimental. It will be
1212 fully supported in 1.5.</dd>
1214 <dt><tt><b>llvm-ar</b></tt></dt>
1215 <dd>The archiver produces an archive containing
1216 the given LLVM bytecode files, optionally with an index for faster
1219 <dt><tt><b>llvm-as</b></tt></dt>
1220 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1223 <dt><tt><b>llvm-dis</b></tt></dt>
1224 <dd>The disassembler transforms the LLVM bytecode to human readable
1227 <dt><tt><b>llvm-ld</b></tt></dt>
1228 <dd><tt>llvm-ld</tt> is very similar to gccld and provides a general purpose
1229 and extensible linker for LLVM. This is the linker invoked by <tt>llvmc</tt>.
1230 It allows optimization modules to be loaded so that language specific
1231 optimizations can be applied at link time. Please note that this tool is new
1232 in LLVM 1.4 and still considered experimental. It will be fully supported in
1235 <dt><tt><b>llvm-link</b></tt></dt>
1236 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1237 a single program.</dd>
1239 <dt><tt><b>lli</b></tt></dt>
1240 <dd><tt>lli</tt> is the LLVM interpreter, which
1241 can directly execute LLVM bytecode (although very slowly...). In addition
1242 to a simple interpreter, <tt>lli</tt> also has a tracing mode (entered by
1243 specifying <tt>-trace</tt> on the command line). Finally, for
1244 architectures that support it (currently x86, Sparc, and PowerPC), by default,
1245 <tt>lli</tt> will function as a Just-In-Time compiler (if the
1246 functionality was compiled in), and will execute the code <i>much</i>
1247 faster than the interpreter.</dd>
1249 <dt><tt><b>llc</b></tt></dt>
1250 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1251 translates LLVM bytecode to a SPARC or x86 assembly file, or to C code (with
1252 the -march=c option).</dd>
1254 <dt><tt><b>llvm-gcc</b></tt></dt>
1255 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend
1256 that has been retargeted to emit LLVM code as the machine code output. It
1257 works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
1258 -o</tt> options that are typically used. The source code for the
1259 <tt>llvm-gcc</tt> tool is currently not included in the LLVM CVS tree
1260 because it is quite large and not very interesting.
1263 <dt><tt><b>gccas</b></tt></dt>
1264 <dd>This tool is invoked by the <tt>llvm-gcc</tt> frontend as the
1265 "assembler" part of the compiler. This tool actually assembles LLVM
1266 assembly to LLVM bytecode, performs a variety of optimizations, and
1267 outputs LLVM bytecode. Thus when you invoke
1268 <tt>llvm-gcc -c x.c -o x.o</tt>, you are causing <tt>gccas</tt> to be
1269 run, which writes the <tt>x.o</tt> file (which is an LLVM bytecode file
1270 that can be disassembled or manipulated just like any other bytecode
1271 file). The command line interface to <tt>gccas</tt> is designed to be
1272 as close as possible to the <b>system</b> `<tt>as</tt>' utility so that
1273 the gcc frontend itself did not have to be modified to interface to
1274 a "weird" assembler.</dd>
1276 <dt><tt><b>gccld</b></tt></dt>
1277 <dd><tt>gccld</tt> links together several LLVM bytecode files into one
1278 bytecode file and does some optimization. It is the linker invoked by
1279 the GCC frontend when multiple .o files need to be linked together.
1280 Like <tt>gccas</tt>, the command line interface of <tt>gccld</tt> is
1281 designed to match the system linker, to aid interfacing with the GCC
1287 <dt><tt><b>opt</b></tt></dt>
1288 <dd><tt>opt</tt> reads LLVM bytecode, applies a
1289 series of LLVM to LLVM transformations (which are specified on the command
1290 line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
1291 command is a good way to get a list of the program transformations
1292 available in LLVM.</dd>
1296 <!-- ======================================================================= -->
1297 <div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1298 <div class="doc_text">
1300 <p>This directory contains utilities for working with LLVM source code, and some
1301 of the utilities are actually required as part of the build process because they
1302 are code generators for parts of LLVM infrastructure.</p>
1305 <dt><tt><b>Burg/</b></tt> <dd><tt>Burg</tt> is an instruction selector
1306 generator -- it builds trees on which it then performs pattern-matching to
1307 select instructions according to the patterns the user has specified. Burg
1308 is currently used in the Sparc V9 backend.<p>
1310 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1311 that finds differences between code that LLC generates and code that LLI
1312 generates. This is a useful tool if you are debugging one of them,
1313 assuming that the other generates correct output. For the full user
1314 manual, run <tt>`perldoc codegen-diff'</tt>.<p>
1316 <dt><tt><b>cvsupdate</b></tt> <dd><tt>cvsupdate</tt> is a script that will
1317 update your CVS tree, but produce a much cleaner and more organized output
1318 than simply running <tt>`cvs -z3 up -dP'</tt> will. For example, it will group
1319 together all the new and updated files and modified files in separate
1320 sections, so you can see at a glance what has changed. If you are at the
1321 top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
1322 preferred way of updating the tree.<p>
1324 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1325 syntax-highlighting files which will work with Emacs and XEmacs editors,
1326 providing syntax highlighting support for LLVM assembly files and TableGen
1327 description files. For information on how to use the syntax files, consult
1328 the <tt>README</tt> file in that directory.<p>
1330 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1331 and outputs all non-generated source files, which is useful if one wishes
1332 to do a lot of development across directories and does not want to
1333 individually find each file. One way to use it is to run, for example:
1334 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1337 <dt><tt><b>llvmgrep</b></tt></dt>
1338 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1339 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1340 line. This is a very efficient way of searching the source base for a
1341 particular regular expression.</dd>
1343 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1344 files in the current directory and then compiles and links the tool that
1345 is the first argument. For example, assuming you are in the directory
1346 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1347 simply running <tt>makellvm llc</tt> will make a build of the current
1348 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1349 causing a re-linking of LLC.<p>
1351 <dt><tt><b>NightlyTest.pl</b></tt> and
1352 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1353 cron script to generate nightly status reports of the functionality of
1354 tools, and the results can be seen by following the appropriate link on
1355 the <a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a>.<p>
1357 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1358 the tool used to generate register descriptions, instruction set
1359 descriptions, and even assemblers from common TableGen description
1362 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1363 syntax-highlighting files which will work with the VIM editor, providing
1364 syntax highlighting support for LLVM assembly files and TableGen
1365 description files. For information on how to use the syntax files, consult
1366 the <tt>README</tt> file in that directory.<p>
1372 <!-- ======================================================================= -->
1373 <div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1374 <div class="doc_text">
1375 <p>This directory contains build scripts and project files for use with
1376 Visual C++. This allows developers on Windows to build LLVM without the need
1377 for Cygwin. The contents of this directory should be considered experimental
1381 <!-- *********************************************************************** -->
1382 <div class="doc_section">
1383 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1385 <!-- *********************************************************************** -->
1387 <div class="doc_text">
1390 <li>First, create a simple C file, name it 'hello.c':
1392 #include <stdio.h>
1394 printf("hello world\n");
1399 <li><p>Next, compile the C file into a LLVM bytecode file:</p>
1400 <p><tt>% llvm-gcc hello.c -o hello</tt></p>
1402 <p>Note that you should have already built the tools and they have to be
1403 in your path, at least <tt>gccas</tt> and <tt>gccld</tt>.</p>
1405 <p>This will create two result files: <tt>hello</tt> and
1406 <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
1407 corresponds the the compiled program and the library facilities that it
1408 required. <tt>hello</tt> is a simple shell script that runs the bytecode
1409 file with <tt>lli</tt>, making the result directly executable. Note that
1410 all LLVM optimizations are enabled by default, so there is no need for a
1411 "-O3" switch.</p></li>
1413 <li><p>Run the program. To make sure the program ran, execute one of the
1414 following commands:</p>
1416 <p><tt>% ./hello</tt></p>
1420 <p><tt>% lli hello.bc</tt></p></li>
1422 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1425 <p><tt>% llvm-dis < hello.bc | less</tt><p></li>
1427 <li><p>Compile the program to native assembly using the LLC code
1430 <p><tt>% llc hello.bc -o hello.s</tt></p>
1432 <li><p>Assemble the native assembly language file into a program:</p>
1434 <p><b>Solaris:</b><tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native</tt></p>
1435 <p><b>Others:</b><tt>% gcc hello.s -o hello.native</tt></p>
1437 <li><p>Execute the native code program:</p>
1439 <p><tt>% ./hello.native</tt></p></li>
1445 <!-- *********************************************************************** -->
1446 <div class="doc_section">
1447 <a name="problems">Common Problems</a>
1449 <!-- *********************************************************************** -->
1451 <div class="doc_text">
1453 <p>If you are having problems building or using LLVM, or if you have any other
1454 general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1455 Asked Questions</a> page.</p>
1459 <!-- *********************************************************************** -->
1460 <div class="doc_section">
1461 <a name="links">Links</a>
1463 <!-- *********************************************************************** -->
1465 <div class="doc_text">
1467 <p>This document is just an <b>introduction</b> to how to use LLVM to do
1468 some simple things... there are many more interesting and complicated things
1469 that you can do that aren't documented here (but we'll gladly accept a patch
1470 if you want to write something up!). For more information about LLVM, check
1474 <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
1475 <li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
1476 <li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project
1477 that Uses LLVM</a></li>
1482 <!-- *********************************************************************** -->
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1491 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1492 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1493 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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