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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>
94 <!-- *********************************************************************** -->
95 <div class="doc_section">
96 <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
98 <!-- *********************************************************************** -->
100 <div class="doc_text">
102 <p>Here's the short story for getting up and running quickly with LLVM:</p>
105 <li>Read the documentation.</li>
106 <li>Read the documentation.</li>
107 <li>Remember that you were warned twice about reading the documentation.</li>
108 <li>Install the GCC front end:
110 <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt>
111 <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf -</tt>
112 <li><b>Sparc and MacOS X Only:</b><br>
113 <tt>cd cfrontend/<i>platform</i><br>
117 <li>Get the Source Code
119 <li>With the distributed files:
121 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
122 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
126 <li>With anonymous CVS access (or use a <a href="#mirror">mirror</a>):
128 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
130 :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt></li>
131 <li>Hit the return key when prompted for the password.
132 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm
134 <li><tt>cd llvm</tt></li>
135 <li><tt>cvs up -P -d</tt></li>
139 <li>Configure the LLVM Build Environment
141 <li>Change directory to where you want to store the LLVM object
142 files and run <tt>configure</tt> to configure the Makefiles and
143 header files for the default platform. Useful options include:
145 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
146 <p>Specify the full pathname of where the LLVM GCC frontend is
148 <li><tt>--enable-spec2000=<i>directory</i></tt>
149 <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
150 benchmarks should be available in
151 <tt><i>directory</i></tt>.</p></li>
155 <li>Build the LLVM Suite:
157 <li>Set your LLVM_LIB_SEARCH_PATH environment variable.</li>
158 <li><tt>gmake -k |& tee gnumake.out
159 # this is csh or tcsh syntax</tt></li>
160 <li>If you get an "internal compiler error (ICE)" see <a href="#brokengcc">below</a>.</li>
165 <p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
166 detailed information on configuring and compiling LLVM. See <a
167 href="#environment">Setting Up Your Environment</a> for tips that simplify
168 working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
169 Layout</a> to learn about the layout of the source code tree.</p>
173 <!-- *********************************************************************** -->
174 <div class="doc_section">
175 <a name="requirements"><b>Requirements</b></a>
177 <!-- *********************************************************************** -->
179 <div class="doc_text">
181 <p>Before you begin to use the LLVM system, review the requirements given below.
182 This may save you some trouble by knowing ahead of time what hardware and
183 software you will need.</p>
187 <!-- ======================================================================= -->
188 <div class="doc_subsection">
189 <a name="hardware"><b>Hardware</b></a>
192 <div class="doc_text">
194 <p>LLVM is known to work on the following platforms:</p>
196 <table cellpadding="3">
204 <td>x86<sup>1</sup></td>
209 <td>V9 (Ultrasparc)</td>
214 <td>x86<sup>1</sup></td>
218 <td>MacOS X<sup>2</sup></td>
223 <td>Cygwin/Win32</td>
224 <td>x86<sup>1</sup></td>
229 <p>LLVM has partial support for the following platforms:</p>
239 <td>x86<sup>1</sup></td>
240 <td>Visual Studio .NET<sup>4,5</sup>, MinGW</td>
242 <td>AIX<sup>3,4</sup></td>
247 <td>Linux<sup>3,5</sup></td>
255 <sup>1</sup> Code generation supported for Pentium processors and up<br>
256 <sup>2</sup> Code generation supported for 32-bit ABI only<br>
257 <sup>3</sup> No native code generation<br>
258 <sup>4</sup> Build is not complete: one or more tools don't link<br>
259 <sup>5</sup> The GCC-based C/C++ frontend does not build<br>
262 <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
263 mode, depending on the system (because of all the debug info), and the libraries
264 appear in more than one of the tools that get linked, so there is some
265 duplication. If you do not need many of the tools and you are space-conscious,
266 you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
267 build requires considerably less space.</p>
269 <p>The LLVM suite <i>may</i> compile on other platforms, but it is not
270 guaranteed to do so. If compilation is successful, the LLVM utilities should be
271 able to assemble, disassemble, analyze, and optimize LLVM bytecode. Code
272 generation should work as well, although the generated native code may not work
273 on your platform.</p>
275 <p>The GCC front end is not very portable at the moment. If you want to get it
276 to work on another platform, you can download a copy of the source and <a
277 href="CFEBuildInstrs.html">try to compile it</a> on your platform.</p>
281 <!-- ======================================================================= -->
282 <div class="doc_subsection"><a name="software"><b>Software</b></a></div>
283 <div class="doc_text">
284 <p>Compiling LLVM requires that you have several software packages
285 installed. The table below lists those required packages. The Package column
286 is the usual name for the software package that LLVM depends on. The Version
287 column provides "known to work" versions of the package. The Notes column
288 describes how LLVM uses the package and provides other details.</p>
290 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
293 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
294 <td>3.79, 3.79.1</td>
295 <td>Makefile/build processor</td>
299 <td><a href="http://gcc.gnu.org">GCC</a></td>
301 <td>C/C++ compiler (<a href="#Note3">Note 3</a>)</td>
305 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
307 <td>LEX compiler</td>
311 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
313 <td>YACC compiler</td>
317 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
319 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
323 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
325 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
329 <td><a href="http://expect.nist.gov/">expect</a></td>
331 <td>Automated test suite (<a href="#Note2">Note 2</a>)</td>
335 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
337 <td>Macro processor for configuration (<a href="#Note1">Note 1</a>)</td>
341 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
343 <td>Configuration script builder (<a href="#Note1">Note 1</a>)</td>
347 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
349 <td>aclocal macro generator (<a href="#Note1">Note 1</a>)</td>
353 <td><a href="http://www.perl.com/download.csp">perl</a></td>
355 <td>Nightly tester, utilities</td>
359 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
361 <td>Shared library manager (<a href="#Note1">Note 1</a>)</td>
365 <td><a href="https://www.cvshome.org/downloads.html">CVS</a></td>
367 <td>CVS access to LLVM (<a href="#Note4">Note 4</a>)</td>
374 <li><a name="Note1">If you want to make changes to the configure scripts,
375 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
376 or higher). You will also need automake. We only use aclocal from that
378 <li><a name="Note2">Only needed if you want to run the automated test
379 suite in the <tt>test</tt> directory.</a></li>
381 <li><a name="Note3">Only the C and C++ languages are needed so there's no
382 need to build the other languages for LLVM's purposes.</a> See
383 <a href="#brokengcc">below</a> for specific version info.
385 <li><a name="Note4">You only need CVS if you intend to build from the
386 latest LLVM sources. If you're working from a release distribution, you
387 don't need CVS.</a></li>
389 <p>Additionally, your compilation host is expected to have the usual
390 plethora of Unix utilities. Specifically:</p>
392 <li><b>ar</b> - archive library builder</li>
393 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
394 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
395 <li><b>chmod</b> - change permissions on a file</li>
396 <li><b>cat</b> - output concatenation utility</li>
397 <li><b>cp</b> - copy files</li>
398 <li><b>date</b> - print the current date/time </li>
399 <li><b>echo</b> - print to standard output</li>
400 <li><b>egrep</b> - extended regular expression search utility</li>
401 <li><b>etags</b> - C/C++ tag file creator for vim/emacs</li>
402 <li><b>find</b> - find files/dirs in a file system</li>
403 <li><b>grep</b> - regular expression search utility</li>
404 <li><b>gzip*</b> - gzip command for distribution generation</li>
405 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
406 <li><b>install</b> - install directories/files </li>
407 <li><b>mkdir</b> - create a directory</li>
408 <li><b>mv</b> - move (rename) files</li>
409 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
410 <li><b>rm</b> - remove (delete) files and directories</li>
411 <li><b>sed</b> - stream editor for transforming output</li>
412 <li><b>sh</b> - Bourne shell for make build scripts</li>
413 <li><b>tar</b> - tape archive for distribution generation</li>
414 <li><b>test</b> - test things in file system</li>
415 <li><b>unzip*</b> - unzip command for distribution checking</li>
416 <li><b>zip*</b> - zip command for distribution generation</li>
420 <!-- ======================================================================= -->
421 <div class="doc_subsection">
422 <a name="brokengcc">Broken versions of GCC</a>
425 <div class="doc_text">
427 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
428 bugs in the compiler. In particular, several versions of GCC crash when trying
429 to compile LLVM. We routinely use GCC 3.3.3 and GCC 3.4.0 and have had success
430 with them. Other versions of GCC will probably work as well. GCC versions listed
431 here are known to not work. If you are using one of these versions, please try
432 to upgrade your GCC to something more recent. If you run into a problem with a
433 version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
434 us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
435 of GCC you are using.
438 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
439 problems in the STL that effectively prevent it from compiling LLVM.
442 <p><b>GCC 3.2.2</b>: This version of GCC fails to compile LLVM.</p>
444 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
445 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
446 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
451 <!-- *********************************************************************** -->
452 <div class="doc_section">
453 <a name="starting"><b>Getting Started with LLVM</b></a>
455 <!-- *********************************************************************** -->
457 <div class="doc_text">
459 <p>The remainder of this guide is meant to get you up and running with
460 LLVM and to give you some basic information about the LLVM environment.</p>
462 <p>The later sections of this guide describe the <a
463 href="#layout">general layout</a> of the the LLVM source tree, a <a
464 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
465 href="#links">links</a> to find more information about LLVM or to get
469 <!-- ======================================================================= -->
470 <div class="doc_subsection">
471 <a name="terminology">Terminology and Notation</a>
474 <div class="doc_text">
476 <p>Throughout this manual, the following names are used to denote paths
477 specific to the local system and working environment. <i>These are not
478 environment variables you need to set but just strings used in the rest
479 of this document below</i>. In any of the examples below, simply replace
480 each of these names with the appropriate pathname on your local system.
481 All these paths are absolute:</p>
486 This is the top level directory of the LLVM source tree.
491 This is the top level directory of the LLVM object tree (i.e. the
492 tree where object files and compiled programs will be placed. It
493 can be the same as SRC_ROOT).
498 This is the where the LLVM GCC Front End is installed.
500 For the pre-built GCC front end binaries, the LLVMGCCDIR is
501 <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
506 <!-- ======================================================================= -->
507 <div class="doc_subsection">
508 <a name="environment">Setting Up Your Environment</a>
511 <div class="doc_text">
514 In order to compile and use LLVM, you will need to set some environment
515 variables. There are also some shell aliases which you may find useful.
516 You can set these on the command line, or better yet, set them in your
517 <tt>.cshrc</tt> or <tt>.profile</tt>.
520 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt><i>LLVMGCCDIR</i>/bytecode-libs</tt>
522 This environment variable helps the LLVM GCC front end find bytecode
523 libraries that it will need for compilation.
526 <dt>alias llvmgcc <i>LLVMGCCDIR</i><tt>/bin/gcc</tt>
527 <dt>alias llvmg++ <i>LLVMGCCDIR</i><tt>/bin/g++</tt>
529 This alias allows you to use the LLVM C and C++ front ends without putting
530 them in your <tt>PATH</tt> or typing in their complete pathnames.
535 <!-- ======================================================================= -->
536 <div class="doc_subsection">
537 <a name="unpack">Unpacking the LLVM Archives</a>
540 <div class="doc_text">
543 If you have the LLVM distribution, you will need to unpack it before you
544 can begin to compile it. LLVM is distributed as a set of two files: the LLVM
545 suite and the LLVM GCC front end compiled for your platform. Each
546 file is a TAR archive that is compressed with the gzip program.
549 <p> The files are as follows:
551 <dt><tt>llvm-1.4.tar.gz</tt></dt>
552 <dd>This is the source code for the LLVM libraries and tools.<br/></dd>
554 <dt><tt>llvm-test-1.4.tar.gz</tt></dt>
555 <dd>This is the source code for the LLVM test suite</tt></dd>
557 <dt><tt>cfrontend-1.4.source.tar.gz</tt></dt>
558 <dd>This is the source release of the GCC front end.<br/></dd>
560 <dt><tt>cfrontend-1.4.sparc-sun-solaris2.8.tar.gz</tt></dt>
561 <dd>This is the binary release of the GCC front end for Solaris/Sparc.
564 <dt><tt>cfrontend-1.4.i686-redhat-linux-gnu.tar.gz</tt></dt>
565 <dd>This is the binary release of the GCC front end for Linux/x86.<br/></dd>
567 <dt><tt>cfrontend-1.4.i386-unknown-freebsd5.1.tar.gz</tt></dt>
568 <dd>This is the binary release of the GCC front end for FreeBSD/x86.<br/></dd>
570 <dt><tt>cfrontend-1.4.powerpc-apple-darwin7.0.0.tar.gz</tt></dt>
571 <dd>This is the binary release of the GCC front end for MacOS X/PPC.<br/></dd>
576 <!-- ======================================================================= -->
577 <div class="doc_subsection">
578 <a name="checkout">Checkout LLVM from CVS</a>
581 <div class="doc_text">
583 <p>If you have access to our CVS repository, you can get a fresh copy of
584 the entire source code. All you need to do is check it out from CVS as
588 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
589 <li><tt>cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
590 <li>Hit the return key when prompted for the password.
591 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co
595 <p>This will create an '<tt>llvm</tt>' directory in the current
596 directory and fully populate it with the LLVM source code, Makefiles,
597 test directories, and local copies of documentation files.</p>
599 <p>If you want to get a specific release (as opposed to the most recent
600 revision), you can specify a label. The following releases have the following
604 <li>Release 1.4: <b>RELEASE_14</b></li>
605 <li>Release 1.3: <b>RELEASE_13</b></li>
606 <li>Release 1.2: <b>RELEASE_12</b></li>
607 <li>Release 1.1: <b>RELEASE_11</b></li>
608 <li>Release 1.0: <b>RELEASE_1</b></li>
611 <p>If you would like to get the LLVM test suite (a separate package as of 1.4),
612 you get it from the CVS repository:</p>
615 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-test
617 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
618 configured by the LLVM configure script as well as automatically updated when
619 you run <tt>cvs update</tt>.</p>
621 <p>If you would like to get the GCC front end source code, you can also get it
622 from the CVS repository:</p>
625 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-gcc
628 <p>Please note that you must follow <a href="CFEBuildInstrs.html">these
629 instructions</a> to successfully build the LLVM C front-end.</p>
633 <!-- ======================================================================= -->
634 <div class="doc_subsubsection">
635 <a name="mirrors">LLVM CVS Mirrors</a>
638 <div class="doc_text">
640 <p>If the main CVS server is overloaded or inaccessible, you can try one of
641 these user-hosted mirrors:</p>
644 <li><a href="http://llvm.x10sys.com/">Mirror hosted by eXtensible Systems
649 <!-- ======================================================================= -->
650 <div class="doc_subsection">
651 <a name="installcf">Install the GCC Front End</a>
654 <div class="doc_text">
656 <p>Before configuring and compiling the LLVM suite, you need to extract the LLVM
657 GCC front end from the binary distribution. It is used for building the
658 bytecode libraries later used by the GCC front end for linking programs, and its
659 location must be specified when the LLVM suite is configured.</p>
661 <p>To install the GCC front end, do the following:</p>
664 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
665 <li><tt>gunzip --stdout cfrontend-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
669 <p>If you are using Solaris/Sparc or MacOS X/PPC, you will need to fix the
672 <p><tt>cd cfrontend/<i>platform</i><br>
673 ./fixheaders</tt></p>
675 <p>The binary versions of the GCC front end may not suit all of your needs. For
676 example, the binary distribution may include an old version of a system header
677 file, not "fix" a header file that needs to be fixed for GCC, or it may be
678 linked with libraries not available on your system.</p>
680 <p>In cases like these, you may want to try <a
681 href="CFEBuildInstrs.html">building the GCC front end from source.</a> This is
682 not for the faint of heart, so be forewarned.</p>
686 <!-- ======================================================================= -->
687 <div class="doc_subsection">
688 <a name="config">Local LLVM Configuration</a>
691 <div class="doc_text">
693 <p>Once checked out from the CVS repository, the LLVM suite source code must be
694 configured via the <tt>configure</tt> script. This script sets variables in the
695 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
696 <tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
697 the Makefiles needed to begin building LLVM.</p>
699 <p>The following environment variables are used by the <tt>configure</tt>
700 script to configure the build system:</p>
703 <tr><th>Variable</th><th>Purpose</th></tr>
706 <td>Tells <tt>configure</tt> which C compiler to use. By default,
707 <tt>configure</tt> will look for the first GCC C compiler in
708 <tt>PATH</tt>. Use this variable to override
709 <tt>configure</tt>'s default behavior.</td>
713 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
714 <tt>configure</tt> will look for the first GCC C++ compiler in
715 <tt>PATH</tt>. Use this variable to override
716 <tt>configure</tt>'s default behavior.</td>
720 <p>The following options can be used to set or enable LLVM specific options:</p>
723 <dt><i>--with-llvmgccdir=LLVMGCCDIR</i></dt>
725 Path to the location where the LLVM GCC front end binaries and
726 associated libraries were installed. This must be specified as an
730 <dt><i>--with-tclinclude</i></dt>
731 <dd>Path to the tcl include directory under which the <tt>tclsh</tt> can be
732 found. Use this if you have multiple tcl installations on your machine and you
733 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
734 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
735 option, the LLVM configure script will search for tcl 8.4 and 8.3 releases.
737 <dt><i>--enable-optimized</i></dt>
739 Enables optimized compilation by default (debugging symbols are removed
740 and GCC optimization flags are enabled). The default is to use an
741 unoptimized build (also known as a debug build).
744 <dt><i>--enable-jit</i></dt>
746 Compile the Just In Time (JIT) compiler functionality. This is not
748 on all platforms. The default is dependent on platform, so it is best
749 to explicitly enable it if you want it.
752 <dt><i>--enable-doxygen</i></dt>
753 <dd>Look for the doxygen program and enable construction of doxygen based
754 documentation from the source code. This is disabled by default because
755 generating the documentation can take a long time and producess 100s of
756 megabytes of output.</dd>
759 <p>To configure LLVM, follow these steps:</p>
762 <li>Change directory into the object root directory:
764 <tt>cd <i>OBJ_ROOT</i></tt>
767 <li>Run the <tt>configure</tt> script located in the LLVM source tree:
769 <tt><i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</tt>
773 <p>In addition to running <tt>configure</tt>, you must set the
774 <tt>LLVM_LIB_SEARCH_PATH</tt> environment variable in your startup shell
775 scripts. This environment variable is used to locate "system" libraries like
776 "<tt>-lc</tt>" and "<tt>-lm</tt>" when linking. This variable should be set to
777 the absolute path of the <tt>bytecode-libs</tt> subdirectory of the GCC front
778 end, or <i>LLVMGCCDIR</i>/<tt>bytecode-libs</tt>. For example, one might set
779 <tt>LLVM_LIB_SEARCH_PATH</tt> to
780 <tt>/home/vadve/lattner/local/x86/llvm-gcc/bytecode-libs</tt> for the x86
781 version of the GCC front end on our research machines.</p>
785 <!-- ======================================================================= -->
786 <div class="doc_subsection">
787 <a name="compile">Compiling the LLVM Suite Source Code</a>
790 <div class="doc_text">
792 <p>Once you have configured LLVM, you can build it. There are three types of
798 These builds are the default when one types <tt>gmake</tt> (unless the
799 <tt>--enable-optimized</tt> option was used during configuration). The
800 build system will compile the tools and libraries with debugging
804 <dt>Release (Optimized) Builds
806 These builds are enabled with the <tt>--enable-optimized</tt> option to
807 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
808 <tt>gmake</tt> command line. For these builds, the build system will
809 compile the tools and libraries with GCC optimizations enabled and strip
810 debugging information from the libraries and executables it generates.
815 These builds are for use with profiling. They compile profiling
816 information into the code for use with programs like <tt>gprof</tt>.
817 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
818 on the <tt>gmake</tt> command line.
821 <p>Once you have LLVM configured, you can build it by entering the
822 <i>OBJ_ROOT</i> directory and issuing the following command:</p>
824 <p><tt>gmake</tt></p>
826 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
827 are using a known broken version of GCC to compile LLVM with.</p>
830 If you have multiple processors in your machine, you may wish to use some of
831 the parallel build options provided by GNU Make. For example, you could use the
834 <p><tt>gmake -j2</tt></p>
836 <p>There are several special targets which are useful when working with the LLVM
840 <dt><tt>gmake clean</tt>
842 Removes all files generated by the build. This includes object files,
843 generated C/C++ files, libraries, and executables.
846 <dt><tt>gmake dist-clean</tt>
848 Removes everything that <tt>gmake clean</tt> does, but also removes files
849 generated by <tt>configure</tt>. It attempts to return the source tree to the
850 original state in which it was shipped.
853 <dt><tt>gmake install</tt>
855 Installs LLVM header files, libraries, tools and documentation in a hierarchy
856 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
857 defaults to <tt>/usr/local</tt>.
860 <dt><tt>gmake -C runtime install-bytecode</tt>
862 Assuming you built LLVM into $OBJDIR, when this command is run, it will
863 install bytecode libraries into the GCC front end's bytecode library
864 directory. If you need to update your bytecode libraries,
865 this is the target to use once you've built them.
869 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
870 details on these <tt>make</tt> targets and descriptions of other targets
873 <p>It is also possible to override default values from <tt>configure</tt> by
874 declaring variables on the command line. The following are some examples:</p>
877 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
879 Perform a Release (Optimized) build.
882 <dt><tt>gmake ENABLE_PROFILING=1</tt>
884 Perform a Profiling build.
887 <dt><tt>gmake VERBOSE=1</tt>
889 Print what <tt>gmake</tt> is doing on standard output.
892 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
893 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
894 the standard output. This also implies <tt>VERBOSE=1</tt> so the makefile
898 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
899 it and any subdirectories that it contains. Entering any directory inside the
900 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
901 that directory that is out of date.</p>
905 <!-- ======================================================================= -->
906 <div class="doc_subsection">
907 <a name="objfiles">The Location of LLVM Object Files</a>
910 <div class="doc_text">
912 <p>The LLVM build system is capable of sharing a single LLVM source tree among
913 several LLVM builds. Hence, it is possible to build LLVM for several different
914 platforms or configurations using the same source tree.</p>
916 <p>This is accomplished in the typical autoconf manner:</p>
919 <li><p>Change directory to where the LLVM object files should live:</p>
921 <p><tt>cd <i>OBJ_ROOT</i></tt></p></li>
923 <li><p>Run the <tt>configure</tt> script found in the LLVM source
926 <p><tt><i>SRC_ROOT</i>/configure</tt></p></li>
929 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
930 named after the build type:</p>
937 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
939 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
947 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
949 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
957 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
959 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
965 <!-- ======================================================================= -->
966 <div class="doc_subsection">
967 <a name="optionalconfig">Optional Configuration Items</a>
970 <div class="doc_text">
973 If you're running on a linux system that supports the "<a
974 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">
976 module, and you have root access on the system, you can set your system up to
977 execute LLVM bytecode files directly. To do this, use commands like this (the
978 first command may not be required if you are already using the module):</p>
981 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
982 $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
983 $ chmod u+x hello.bc (if needed)
988 This allows you to execute LLVM bytecode files directly. Thanks to Jack
989 Cummings for pointing this out!
995 <!-- *********************************************************************** -->
996 <div class="doc_section">
997 <a name="layout"><b>Program Layout</b></a>
999 <!-- *********************************************************************** -->
1001 <div class="doc_text">
1003 <p>One useful source of information about the LLVM source base is the LLVM <a
1004 href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1005 href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>.
1006 The following is a brief introduction to code layout:</p>
1010 <!-- ======================================================================= -->
1011 <div class="doc_subsection"><a name="cvsdir"><tt>CVS</tt> directories</a></div>
1012 <div class="doc_text">
1013 <p>Every directory checked out of CVS will contain a <tt>CVS</tt> directory; for
1014 the most part these can just be ignored.</p>
1017 <!-- ======================================================================= -->
1018 <div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1019 <div class="doc_text">
1020 <p>This directory contains some simple examples of how to use the LLVM IR and
1024 <!-- ======================================================================= -->
1025 <div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1026 <div class="doc_text">
1028 <p>This directory contains public header files exported from the LLVM
1029 library. The three main subdirectories of this directory are:</p>
1032 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1033 <dd>This directory contains all of the LLVM specific header files. This
1034 directory also has subdirectories for different portions of LLVM:
1035 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1038 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1039 <dd>This directory contains generic support libraries that are provided with
1040 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1041 and a Command Line option processing library store their header files here.
1044 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1045 <dd>This directory contains header files configured by the <tt>configure</tt>
1046 script. They wrap "standard" UNIX and C header files. Source code can
1047 include these header files which automatically take care of the conditional
1048 #includes that the <tt>configure</tt> script generates.</dd>
1052 <!-- ======================================================================= -->
1053 <div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1054 <div class="doc_text">
1056 <p>This directory contains most of the source files of the LLVM system. In LLVM,
1057 almost all code exists in libraries, making it very easy to share code among the
1058 different <a href="#tools">tools</a>.</p>
1061 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1062 <dd> This directory holds the core LLVM source files that implement core
1063 classes like Instruction and BasicBlock.</dd>
1065 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1066 <dd>This directory holds the source code for the LLVM assembly language parser
1069 <dt><tt><b>llvm/lib/ByteCode/</b></tt></dt>
1070 <dd>This directory holds code for reading and write LLVM bytecode.</dd>
1072 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1073 different program analyses, such as Dominator Information, Call Graphs,
1074 Induction Variables, Interval Identification, Natural Loop Identification,
1077 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1078 <dd> This directory contains the source code for the LLVM to LLVM program
1079 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1080 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1081 Elimination, and many others.</dd>
1083 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1084 <dd> This directory contains files that describe various target architectures
1085 for code generation. For example, the <tt>llvm/lib/Target/SparcV9</tt>
1086 directory holds the Sparc machine description while
1087 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter</dd>
1089 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1090 <dd> This directory contains the major parts of the code generator: Instruction
1091 Selector, Instruction Scheduling, and Register Allocation.</dd>
1093 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1094 <dd> This directory contains the source level debugger library that makes
1095 it possible to instrument LLVM programs so that a debugger could identify
1096 source code locations at which the program is executing.</dd>
1098 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1099 <dd> This directory contains libraries for executing LLVM bytecode directly
1100 at runtime in both interpreted and JIT compiled fashions.</dd>
1102 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1103 <dd> This directory contains the source code that corresponds to the header
1104 files located in <tt>llvm/include/Support/</tt>.</dd>
1106 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1107 <dd>This directory contains the operating system abstraction layer that
1108 shields LLVM from platform-specific coding.</dd>
1113 <!-- ======================================================================= -->
1114 <div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1115 <div class="doc_text">
1116 <p>This directory contains projects that are not strictly part of LLVM but are
1117 shipped with LLVM. This is also the directory where you should create your own
1118 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1119 to set up your own project. See <tt>llvm/projects/Stacker</tt> for a fully
1120 functional example of a compiler front end.</p>
1123 <!-- ======================================================================= -->
1124 <div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1125 <div class="doc_text">
1127 <p>This directory contains libraries which are compiled into LLVM bytecode and
1128 used when linking programs with the GCC front end. Most of these libraries are
1129 skeleton versions of real libraries; for example, libc is a stripped down
1130 version of glibc.</p>
1132 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1137 <!-- ======================================================================= -->
1138 <div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1139 <div class="doc_text">
1140 <p>This directory contains feature and regression tests and other basic sanity
1141 checks on the LLVM infrastructure. These are intended to run quickly and cover
1142 a lot of territory without being exhaustive.</p>
1145 <!-- ======================================================================= -->
1146 <div class="doc_subsection"><a name="llvmtest"><tt>llvm-test</tt></a></div>
1147 <div class="doc_text">
1148 <p>This is not a directory in the normal llvm module, it is a separate CVS
1149 module that must be checked out (usually to <tt>projects/llvm-test</tt>). This
1150 module contains a comprehensive correctness, performance and benchmarking test
1151 suite for LLVM. It is a separate CVS module because not every LLVM user is
1152 interested in downloading or building such a comprehensive test. For further
1153 details on this test suite, please see the
1154 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1157 <!-- ======================================================================= -->
1158 <div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1159 <div class="doc_text">
1161 <p>The <b>tools</b> directory contains the executables built out of the
1162 libraries above, which form the main part of the user interface. You can
1163 always get help for a tool by typing <tt>tool_name --help</tt>. The
1164 following is a brief introduction to the most important tools. More detailed
1165 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1168 <dt><tt><b>analyze</b></tt></dt>
1169 <dd><tt>analyze</tt> is used to run a specific
1170 analysis on an input LLVM bytecode file and print out the results. It is
1171 primarily useful for debugging analyses, or familiarizing yourself with
1172 what an analysis does.</dd>
1174 <dt><tt><b>bugpoint</b></tt></dt>
1175 <dd><tt>bugpoint</tt> is used to debug
1176 optimization passes or code generation backends by narrowing down the
1177 given test case to the minimum number of passes and/or instructions that
1178 still cause a problem, whether it is a crash or miscompilation. See <a
1179 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1180 on using <tt>bugpoint</tt>.</dd>
1182 <dt><tt><b>llvmc</b></tt></dt>
1183 <dd>The LLVM Compiler Driver. This program can
1184 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1185 pre-processing, translation, optimization, assembly, and linking of programs
1186 all from one command line. <tt>llvmc</tt> also takes care of processing the
1187 dependent libraries found in bytecode. This reduces the need to get the
1188 traditional <tt>-l<name></tt> options right on the command line.</dd>
1190 <dt><tt><b>llvm-ar</b></tt></dt>
1191 <dd>The archiver produces an archive containing
1192 the given LLVM bytecode files, optionally with an index for faster
1195 <dt><tt><b>llvm-as</b></tt></dt>
1196 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1199 <dt><tt><b>llvm-dis</b></tt></dt>
1200 <dd>The disassembler transforms the LLVM bytecode to human readable
1203 <dt><tt><b>llvm-link</b></tt></dt>
1204 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1205 a single program.</dd>
1207 <dt><tt><b>lli</b></tt></dt>
1208 <dd><tt>lli</tt> is the LLVM interpreter, which
1209 can directly execute LLVM bytecode (although very slowly...). In addition
1210 to a simple interpreter, <tt>lli</tt> also has a tracing mode (entered by
1211 specifying <tt>-trace</tt> on the command line). Finally, for
1212 architectures that support it (currently only x86 and Sparc), by default,
1213 <tt>lli</tt> will function as a Just-In-Time compiler (if the
1214 functionality was compiled in), and will execute the code <i>much</i>
1215 faster than the interpreter.</dd>
1217 <dt><tt><b>llc</b></tt></dt>
1218 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1219 translates LLVM bytecode to a SPARC or x86 assembly file, or to C code (with
1220 the -march=c option).</dd>
1222 <dt><tt><b>llvmgcc</b></tt></dt>
1223 <dd><tt>llvmgcc</tt> is a GCC-based C frontend
1224 that has been retargeted to emit LLVM code as the machine code output. It
1225 works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
1226 -o</tt> options that are typically used. The source code for the
1227 <tt>llvmgcc</tt> tool is currently not included in the LLVM CVS tree
1228 because it is quite large and not very interesting.
1231 <dt><tt><b>gccas</b></tt></dt>
1232 <dd>This tool is invoked by the <tt>llvmgcc</tt> frontend as the
1233 "assembler" part of the compiler. This tool actually assembles LLVM
1234 assembly to LLVM bytecode, performs a variety of optimizations, and
1235 outputs LLVM bytecode. Thus when you invoke
1236 <tt>llvmgcc -c x.c -o x.o</tt>, you are causing <tt>gccas</tt> to be
1237 run, which writes the <tt>x.o</tt> file (which is an LLVM bytecode file
1238 that can be disassembled or manipulated just like any other bytecode
1239 file). The command line interface to <tt>gccas</tt> is designed to be
1240 as close as possible to the <b>system</b> `<tt>as</tt>' utility so that
1241 the gcc frontend itself did not have to be modified to interface to
1242 a "weird" assembler.</dd>
1244 <dt><tt><b>gccld</b></tt></dt>
1245 <dd><tt>gccld</tt> links together several LLVM bytecode files into one
1246 bytecode file and does some optimization. It is the linker invoked by
1247 the GCC frontend when multiple .o files need to be linked together.
1248 Like <tt>gccas</tt>, the command line interface of <tt>gccld</tt> is
1249 designed to match the system linker, to aid interfacing with the GCC
1255 <dt><tt><b>opt</b></tt></dt>
1256 <dd><tt>opt</tt> reads LLVM bytecode, applies a
1257 series of LLVM to LLVM transformations (which are specified on the command
1258 line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
1259 command is a good way to get a list of the program transformations
1260 available in LLVM.</dd>
1264 <!-- ======================================================================= -->
1265 <div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1266 <div class="doc_text">
1268 <p>This directory contains utilities for working with LLVM source code, and some
1269 of the utilities are actually required as part of the build process because they
1270 are code generators for parts of LLVM infrastructure.</p>
1273 <dt><tt><b>Burg/</b></tt> <dd><tt>Burg</tt> is an instruction selector
1274 generator -- it builds trees on which it then performs pattern-matching to
1275 select instructions according to the patterns the user has specified. Burg
1276 is currently used in the Sparc V9 backend.<p>
1278 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1279 that finds differences between code that LLC generates and code that LLI
1280 generates. This is a useful tool if you are debugging one of them,
1281 assuming that the other generates correct output. For the full user
1282 manual, run <tt>`perldoc codegen-diff'</tt>.<p>
1284 <dt><tt><b>cvsupdate</b></tt> <dd><tt>cvsupdate</tt> is a script that will
1285 update your CVS tree, but produce a much cleaner and more organized output
1286 than simply running <tt>`cvs -z3 up -dP'</tt> will. For example, it will group
1287 together all the new and updated files and modified files in separate
1288 sections, so you can see at a glance what has changed. If you are at the
1289 top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
1290 preferred way of updating the tree.<p>
1292 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1293 syntax-highlighting files which will work with Emacs and XEmacs editors,
1294 providing syntax highlighting support for LLVM assembly files and TableGen
1295 description files. For information on how to use the syntax files, consult
1296 the <tt>README</tt> file in that directory.<p>
1298 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1299 and outputs all non-generated source files, which is useful if one wishes
1300 to do a lot of development across directories and does not want to
1301 individually find each file. One way to use it is to run, for example:
1302 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1305 <dt><tt><b>llvmgrep</b></tt></dt>
1306 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1307 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1308 line. This is a very efficient way of searching the source base for a
1309 particular regular expression.</dd>
1311 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1312 files in the current directory and then compiles and links the tool that
1313 is the first argument. For example, assuming you are in the directory
1314 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1315 simply running <tt>makellvm llc</tt> will make a build of the current
1316 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1317 causing a re-linking of LLC.<p>
1319 <dt><tt><b>NightlyTest.pl</b></tt> and
1320 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1321 cron script to generate nightly status reports of the functionality of
1322 tools, and the results can be seen by following the appropriate link on
1323 the <a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a>.<p>
1325 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1326 the tool used to generate register descriptions, instruction set
1327 descriptions, and even assemblers from common TableGen description
1330 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1331 syntax-highlighting files which will work with the VIM editor, providing
1332 syntax highlighting support for LLVM assembly files and TableGen
1333 description files. For information on how to use the syntax files, consult
1334 the <tt>README</tt> file in that directory.<p>
1340 <!-- ======================================================================= -->
1341 <div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1342 <div class="doc_text">
1343 <p>This directory contains build scripts and project files for use with
1344 Visual C++. This allows developers on Windows to build LLVM without the need
1345 for cygwin. The contents of this directory should be considered experimental
1349 <!-- *********************************************************************** -->
1350 <div class="doc_section">
1351 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1353 <!-- *********************************************************************** -->
1355 <div class="doc_text">
1358 <li>First, create a simple C file, name it 'hello.c':
1360 #include <stdio.h>
1362 printf("hello world\n");
1367 <li><p>Next, compile the C file into a LLVM bytecode file:</p>
1368 <p><tt>% llvmgcc hello.c -o hello</tt></p>
1370 <p>Note that you should have already built the tools and they have to be
1371 in your path, at least <tt>gccas</tt> and <tt>gccld</tt>.</p>
1373 <p>This will create two result files: <tt>hello</tt> and
1374 <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
1375 corresponds the the compiled program and the library facilities that it
1376 required. <tt>hello</tt> is a simple shell script that runs the bytecode
1377 file with <tt>lli</tt>, making the result directly executable. Note that
1378 all LLVM optimizations are enabled by default, so there is no need for a
1379 "-O3" switch.</p></li>
1381 <li><p>Run the program. To make sure the program ran, execute one of the
1382 following commands:</p>
1384 <p><tt>% ./hello</tt></p>
1388 <p><tt>% lli hello.bc</tt></p></li>
1390 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1393 <p><tt>% llvm-dis < hello.bc | less</tt><p></li>
1395 <li><p>Compile the program to native assembly using the LLC code
1398 <p><tt>% llc hello.bc -o hello.s</tt></p>
1400 <li><p>Assemble the native assembly language file into a program:</p>
1402 <p><b>Solaris:</b><tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native</tt></p>
1403 <p><b>Others:</b><tt>% gcc hello.s -o hello.native</tt></p>
1405 <li><p>Execute the native code program:</p>
1407 <p><tt>% ./hello.native</tt></p></li>
1413 <!-- *********************************************************************** -->
1414 <div class="doc_section">
1415 <a name="problems">Common Problems</a>
1417 <!-- *********************************************************************** -->
1419 <div class="doc_text">
1421 <p>If you are having problems building or using LLVM, or if you have any other
1422 general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1423 Asked Questions</a> page.</p>
1427 <!-- *********************************************************************** -->
1428 <div class="doc_section">
1429 <a name="links">Links</a>
1431 <!-- *********************************************************************** -->
1433 <div class="doc_text">
1435 <p>This document is just an <b>introduction</b> to how to use LLVM to do
1436 some simple things... there are many more interesting and complicated things
1437 that you can do that aren't documented here (but we'll gladly accept a patch
1438 if you want to write something up!). For more information about LLVM, check
1442 <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
1443 <li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
1444 <li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project
1445 that Uses LLVM</a></li>
1450 <!-- *********************************************************************** -->
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1459 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1460 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1461 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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