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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="#Note4">Note 4</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="http://www.codesourcery.com/qmtest">QMTest</a></td>
367 <td>Automated test suite (<a href="#Note2">Note 2</a>,<a href="#Note3">
372 <td><a href="http://www.python.org">Python</a></td>
374 <td>Automated test suite (<a href="#Note2">Note 2</a>,<a href="#Note3">
379 <td><a href="https://www.cvshome.org/downloads.html">CVS</a></td>
381 <td>CVS access to LLVM (<a href="#Note5">Note 5</a>)</td>
388 <li><a name="Note1">If you want to make changes to the configure scripts,
389 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
390 or higher). You will also need automake. We only use aclocal from that
392 <li><a name="Note2">Only needed if you want to run the automated test
393 suite in the <tt>test</tt> directory.</a></li>
394 <li><a name="Note3">These are needed to use the LLVM test suite.</a>
395 Please note that newer versions of QMTest may not work with the LLVM
396 test suite. QMTest 2.0.3 can be retrieved from the QMTest CVS
397 repository using the following commands:
399 <li><tt>cvs -d :pserver:anoncvs@cvs.codesourcery.com:/home/qm/Repository login</tt></li>
400 <li>When prompted, use <tt>anoncvs</tt> as the password. </li>
401 <li><tt>cvs -d :pserver:anoncvs@cvs.codesourcery.com:/home/qm/Repository co -r release-2-0-3 qm</tt></li>
404 <li><a name="Note4">Only the C and C++ languages are needed so there's no
405 need to build the other languages for LLVM's purposes.</a> See
406 <a href="#brokengcc">below</a> for specific version info.
408 <li><a name="Note5">You only need CVS if you intend to build from the
409 latest LLVM sources. If you're working from a release distribution, you
410 don't need CVS.</a></li>
412 <p>Additionally, your compilation host is expected to have the usual
413 plethora of Unix utilities. Specifically:</p>
415 <li><b>ar</b> - archive library builder</li>
416 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
417 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
418 <li><b>chmod</b> - change permissions on a file</li>
419 <li><b>cat</b> - output concatentation utility</li>
420 <li><b>cp</b> - copy files</li>
421 <li><b>date</b> - print the current date/time </li>
422 <li><b>echo</b> - print to standard output</li>
423 <li><b>egrep</b> - extended regular expression search utility</li>
424 <li><b>etags</b> - C/C++ tag file creator for vim/emacs</li>
425 <li><b>find</b> - find files/dirs in a file system</li>
426 <li><b>grep</b> - regular expression search utility</li>
427 <li><b>gzip*</b> - gzip command for distribution generation</li>
428 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
429 <li><b>install</b> - install directories/files </li>
430 <li><b>mkdir</b> - create a directory</li>
431 <li><b>mv</b> - move (rename) files</li>
432 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
433 <li><b>rm</b> - remove (delete) files and directories</li>
434 <li><b>sed</b> - stream editor for transforming output</li>
435 <li><b>sh</b> - Bourne shell for make build scripts</li>
436 <li><b>tar</b> - tape archive for distribution generation</li>
437 <li><b>test</b> - test things in file system</li>
438 <li><b>unzip*</b> - unzip command for distribution checking</li>
439 <li><b>zip*</b> - zip command for distribution generation</li>
443 <!-- ======================================================================= -->
444 <div class="doc_subsection">
445 <a name="brokengcc">Broken versions of GCC</a>
448 <div class="doc_text">
450 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
451 bugs in the compiler. In particular, several versions of GCC crash when trying
452 to compile LLVM. We routinely use GCC 3.3.3 and GCC 3.4.0 and have had success
453 with them. Other versions of GCC will probably work as well. GCC versions listed
454 here are known to not work. If you are using one of these versions, please try
455 to upgrade your GCC to something more recent. If you run into a problem with a
456 version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
457 us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
458 of GCC you are using.
461 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
462 problems in the STL that effectively prevent it from compiling LLVM.
465 <p><b>GCC 3.2.2</b>: This version of GCC fails to compile LLVM.</p>
467 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
468 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
469 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
474 <!-- *********************************************************************** -->
475 <div class="doc_section">
476 <a name="starting"><b>Getting Started with LLVM</b></a>
478 <!-- *********************************************************************** -->
480 <div class="doc_text">
482 <p>The remainder of this guide is meant to get you up and running with
483 LLVM and to give you some basic information about the LLVM environment.</p>
485 <p>The later sections of this guide describe the <a
486 href="#layout">general layout</a> of the the LLVM source tree, a <a
487 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
488 href="#links">links</a> to find more information about LLVM or to get
492 <!-- ======================================================================= -->
493 <div class="doc_subsection">
494 <a name="terminology">Terminology and Notation</a>
497 <div class="doc_text">
499 <p>Throughout this manual, the following names are used to denote paths
500 specific to the local system and working environment. <i>These are not
501 environment variables you need to set but just strings used in the rest
502 of this document below</i>. In any of the examples below, simply replace
503 each of these names with the appropriate pathname on your local system.
504 All these paths are absolute:</p>
509 This is the top level directory of the LLVM source tree.
514 This is the top level directory of the LLVM object tree (i.e. the
515 tree where object files and compiled programs will be placed. It
516 can be the same as SRC_ROOT).
521 This is the where the LLVM GCC Front End is installed.
523 For the pre-built GCC front end binaries, the LLVMGCCDIR is
524 <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
529 <!-- ======================================================================= -->
530 <div class="doc_subsection">
531 <a name="environment">Setting Up Your Environment</a>
534 <div class="doc_text">
537 In order to compile and use LLVM, you will need to set some environment
538 variables. There are also some shell aliases which you may find useful.
539 You can set these on the command line, or better yet, set them in your
540 <tt>.cshrc</tt> or <tt>.profile</tt>.
543 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt><i>LLVMGCCDIR</i>/bytecode-libs</tt>
545 This environment variable helps the LLVM GCC front end find bytecode
546 libraries that it will need for compilation.
549 <dt>alias llvmgcc <i>LLVMGCCDIR</i><tt>/bin/gcc</tt>
550 <dt>alias llvmg++ <i>LLVMGCCDIR</i><tt>/bin/g++</tt>
552 This alias allows you to use the LLVM C and C++ front ends without putting
553 them in your <tt>PATH</tt> or typing in their complete pathnames.
558 <!-- ======================================================================= -->
559 <div class="doc_subsection">
560 <a name="unpack">Unpacking the LLVM Archives</a>
563 <div class="doc_text">
566 If you have the LLVM distribution, you will need to unpack it before you
567 can begin to compile it. LLVM is distributed as a set of two files: the LLVM
568 suite and the LLVM GCC front end compiled for your platform. Each
569 file is a TAR archive that is compressed with the gzip program.
572 <p> The files are as follows:
575 <dd>This is the source code to the LLVM suite.
578 <dt>cfrontend-1.3.source.tar.gz
579 <dd>This is the source release of the GCC front end.
582 <dt>cfrontend-1.3.sparc-sun-solaris2.8.tar.gz
583 <dd>This is the binary release of the GCC front end for Solaris/Sparc.
586 <dt>cfrontend-1.3.i686-redhat-linux-gnu.tar.gz
587 <dd>This is the binary release of the GCC front end for Linux/x86.
590 <dt>cfrontend-1.3.i386-unknown-freebsd5.1.tar.gz
591 <dd>This is the binary release of the GCC front end for FreeBSD/x86.
594 <dt>cfrontend-1.3.powerpc-apple-darwin7.0.0.tar.gz
595 <dd>This is the binary release of the GCC front end for MacOS X/PPC.
600 <!-- ======================================================================= -->
601 <div class="doc_subsection">
602 <a name="checkout">Checkout LLVM from CVS</a>
605 <div class="doc_text">
607 <p>If you have access to our CVS repository, you can get a fresh copy of
608 the entire source code. All you need to do is check it out from CVS as
612 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
613 <li><tt>cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
614 <li>Hit the return key when prompted for the password.
615 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co
619 <p>This will create an '<tt>llvm</tt>' directory in the current
620 directory and fully populate it with the LLVM source code, Makefiles,
621 test directories, and local copies of documentation files.</p>
623 <p>If you want to get a specific release (as opposed to the most recent
624 revision), you can specify a label. The following releases have the following
628 <li>Release 1.3: <b>RELEASE_13</b></li>
629 <li>Release 1.2: <b>RELEASE_12</b></li>
630 <li>Release 1.1: <b>RELEASE_11</b></li>
631 <li>Release 1.0: <b>RELEASE_1</b></li>
634 <p>If you would like to get the GCC front end source code, you can also get it
635 from the CVS repository:</p>
638 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-gcc
641 <p>Please note that you must follow <a href="CFEBuildInstrs.html">these
642 instructions</a> to successfully build the LLVM C front-end.</p>
646 <!-- ======================================================================= -->
647 <div class="doc_subsubsection">
648 <a name="mirrors">LLVM CVS Mirrors</a>
651 <div class="doc_text">
653 <p>If the main CVS server is overloaded or inaccessible, you can try one of
654 these user-hosted mirrors:</p>
657 <li><a href="http://llvm.x10sys.com/">Mirror hosted by eXtensible Systems
662 <!-- ======================================================================= -->
663 <div class="doc_subsection">
664 <a name="installcf">Install the GCC Front End</a>
667 <div class="doc_text">
669 <p>Before configuring and compiling the LLVM suite, you need to extract the LLVM
670 GCC front end from the binary distribution. It is used for building the
671 bytecode libraries later used by the GCC front end for linking programs, and its
672 location must be specified when the LLVM suite is configured.</p>
674 <p>To install the GCC front end, do the following:</p>
677 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
678 <li><tt>gunzip --stdout cfrontend-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
682 <p>If you are using Solaris/Sparc or MacOS X/PPC, you will need to fix the
685 <p><tt>cd cfrontend/<i>platform</i><br>
686 ./fixheaders</tt></p>
688 <p>The binary versions of the GCC front end may not suit all of your needs. For
689 example, the binary distribution may include an old version of a system header
690 file, not "fix" a header file that needs to be fixed for GCC, or it may be
691 linked with libraries not available on your system.</p>
693 <p>In cases like these, you may want to try <a
694 href="CFEBuildInstrs.html">building the GCC front end from source.</a> This is
695 not for the faint of heart, so be forewarned.</p>
699 <!-- ======================================================================= -->
700 <div class="doc_subsection">
701 <a name="config">Local LLVM Configuration</a>
704 <div class="doc_text">
706 <p>Once checked out from the CVS repository, the LLVM suite source code must be
707 configured via the <tt>configure</tt> script. This script sets variables in
708 <tt>llvm/Makefile.config</tt> and <tt>llvm/include/Config/config.h</tt>. It
709 also populates <i>OBJ_ROOT</i> with the Makefiles needed to begin building
712 <p>The following environment variables are used by the <tt>configure</tt>
713 script to configure the build system:</p>
716 <tr><th>Variable</th><th>Purpose</th></tr>
719 <td>Tells <tt>configure</tt> which C compiler to use. By default,
720 <tt>configure</tt> will look for the first GCC C compiler in
721 <tt>PATH</tt>. Use this variable to override
722 <tt>configure</tt>'s default behavior.</td>
726 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
727 <tt>configure</tt> will look for the first GCC C++ compiler in
728 <tt>PATH</tt>. Use this variable to override
729 <tt>configure</tt>'s default behavior.</td>
733 <p>The following options can be used to set or enable LLVM specific options:</p>
736 <dt><i>--with-llvmgccdir=LLVMGCCDIR</i>
738 Path to the location where the LLVM GCC front end binaries and
739 associated libraries were installed. This must be specified as an
742 <dt><i>--enable-optimized</i>
744 Enables optimized compilation by default (debugging symbols are removed
745 and GCC optimization flags are enabled). The default is to use an
746 unoptimized build (also known as a debug build).
748 <dt><i>--enable-jit</i>
750 Compile the Just In Time (JIT) compiler functionality. This is not
752 on all platforms. The default is dependent on platform, so it is best
753 to explicitly enable it if you want it.
755 <dt><i>--enable-spec2000</i>
756 <dt><i>--enable-spec2000=<<tt>directory</tt>></i>
758 Enable the use of SPEC2000 when testing LLVM. This is disabled by default
759 (unless <tt>configure</tt> finds SPEC2000 installed). By specifying
760 <tt>directory</tt>, you can tell configure where to find the SPEC2000
761 benchmarks. If <tt>directory</tt> is left unspecified, <tt>configure</tt>
762 uses the default value
763 <tt>/home/vadve/shared/benchmarks/speccpu2000/benchspec</tt>.
765 <dt><i>--enable-spec95</i>
766 <dt><i>--enable-spec95=<<tt>directory</tt>></i>
768 Enable the use of SPEC95 when testing LLVM. It is similar to the
769 <i>--enable-spec2000</i> option.
771 <dt><i>--enable-povray</i>
772 <dt><i>--enable-povray=<<tt>directory</tt>></i>
774 Enable the use of Povray as an external test. Versions of Povray written
775 in C should work. This option is similar to the <i>--enable-spec2000</i>
779 <p>To configure LLVM, follow these steps:</p>
782 <li>Change directory into the object root directory:
784 <tt>cd <i>OBJ_ROOT</i></tt>
787 <li>Run the <tt>configure</tt> script located in the LLVM source tree:
789 <tt><i>SRC_ROOT</i>/configure</tt>
793 <p>In addition to running <tt>configure</tt>, you must set the
794 <tt>LLVM_LIB_SEARCH_PATH</tt> environment variable in your startup scripts.
795 This environment variable is used to locate "system" libraries like
796 "<tt>-lc</tt>" and "<tt>-lm</tt>" when linking. This variable should be set to
797 the absolute path of the <tt>bytecode-libs</tt> subdirectory of the GCC front
798 end, or <i>LLVMGCCDIR</i>/<tt>bytecode-libs</tt>. For example, one might set
799 <tt>LLVM_LIB_SEARCH_PATH</tt> to
800 <tt>/home/vadve/lattner/local/x86/llvm-gcc/bytecode-libs</tt> for the x86
801 version of the GCC front end on our research machines.</p>
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 known broken version of GCC to compile LLVM with.</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 distclean</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 libraries and tools in a heirarchy under $PREFIX, specified with
876 <tt>./configure --prefix=[dir]</tt>, defaults to <tt>/usr/local</tt>.
879 <dt><tt>gmake -C runtime install</tt>
881 Assuming you built LLVM into $OBJDIR, when this command is run, it will
882 install bytecode libraries into the GCC front end's bytecode library
883 directory. If you need to update your bytecode libraries,
884 this is the target to use once you've built them.
888 <p>It is also possible to override default values from <tt>configure</tt> by
889 declaring variables on the command line. The following are some examples:</p>
892 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
894 Perform a Release (Optimized) build.
897 <dt><tt>gmake ENABLE_PROFILING=1</tt>
899 Perform a Profiling build.
902 <dt><tt>gmake VERBOSE=1</tt>
904 Print what <tt>gmake</tt> is doing on standard output.
908 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
909 it and any subdirectories that it contains. Entering any directory inside the
910 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
911 that directory that is out of date.</p>
915 <!-- ======================================================================= -->
916 <div class="doc_subsection">
917 <a name="objfiles">The Location of LLVM Object Files</a>
920 <div class="doc_text">
922 <p>The LLVM build system is capable of sharing a single LLVM source tree among
923 several LLVM builds. Hence, it is possible to build LLVM for several different
924 platforms or configurations using the same source tree.</p>
926 <p>This is accomplished in the typical autoconf manner:</p>
929 <li><p>Change directory to where the LLVM object files should live:</p>
931 <p><tt>cd <i>OBJ_ROOT</i></tt></p></li>
933 <li><p>Run the <tt>configure</tt> script found in the LLVM source
936 <p><tt><i>SRC_ROOT</i>/configure</tt></p></li>
939 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
940 named after the build type:</p>
947 <dd><tt><i>OBJ_ROOT</i>/tools/Debug</tt>
949 <dd><tt><i>OBJ_ROOT</i>/lib/Debug</tt>
957 <dd><tt><i>OBJ_ROOT</i>/tools/Release</tt>
959 <dd><tt><i>OBJ_ROOT</i>/lib/Release</tt>
967 <dd><tt><i>OBJ_ROOT</i>/tools/Profile</tt>
969 <dd><tt><i>OBJ_ROOT</i>/lib/Profile</tt>
975 <!-- ======================================================================= -->
976 <div class="doc_subsection">
977 <a name="optionalconfig">Optional Configuration Items</a>
980 <div class="doc_text">
983 If you're running on a linux system that supports the "<a
984 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
985 module, and you have root access on the system, you can set your system up to
986 execute LLVM bytecode files directly. To do this, use commands like this (the
987 first command may not be required if you are already using the module):</p>
990 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
991 $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
992 $ chmod u+x hello.bc (if needed)
997 This allows you to execute LLVM bytecode files directly. Thanks to Jack
998 Cummings for pointing this out!
1004 <!-- *********************************************************************** -->
1005 <div class="doc_section">
1006 <a name="layout"><b>Program Layout</b></a>
1008 <!-- *********************************************************************** -->
1010 <div class="doc_text">
1012 <p>One useful source of information about the LLVM source base is the LLVM <a
1013 href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1014 href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>.
1015 The following is a brief introduction to code layout:</p>
1019 <!-- ======================================================================= -->
1020 <div class="doc_subsection"><a name="cvsdir"><tt>CVS</tt> directories</a></div>
1021 <div class="doc_text">
1022 <p>Every directory checked out of CVS will contain a <tt>CVS</tt> directory; for
1023 the most part these can just be ignored.</p>
1026 <!-- ======================================================================= -->
1027 <div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1028 <div class="doc_text">
1029 <p>This directory contains some simple examples of how to use the LLVM IR and
1033 <!-- ======================================================================= -->
1034 <div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1035 <div class="doc_text">
1037 <p>This directory contains public header files exported from the LLVM
1038 library. The three main subdirectories of this directory are:</p>
1041 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1042 <dd>This directory contains all of the LLVM specific header files. This
1043 directory also has subdirectories for different portions of LLVM:
1044 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1047 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1048 <dd>This directory contains generic support libraries that are provided with
1049 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1050 and a Command Line option processing library store their header files here.
1053 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1054 <dd>This directory contains header files configured by the <tt>configure</tt>
1055 script. They wrap "standard" UNIX and C header files. Source code can
1056 include these header files which automatically take care of the conditional
1057 #includes that the <tt>configure</tt> script generates.</dd>
1061 <!-- ======================================================================= -->
1062 <div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1063 <div class="doc_text">
1065 <p>This directory contains most of the source files of the LLVM system. In LLVM,
1066 almost all code exists in libraries, making it very easy to share code among the
1067 different <a href="#tools">tools</a>.</p>
1070 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1071 <dd> This directory holds the core LLVM source files that implement core
1072 classes like Instruction and BasicBlock.</dd>
1074 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1075 <dd>This directory holds the source code for the LLVM assembly language parser
1078 <dt><tt><b>llvm/lib/ByteCode/</b></tt></dt>
1079 <dd>This directory holds code for reading and write LLVM bytecode.</dd>
1081 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1082 different program analyses, such as Dominator Information, Call Graphs,
1083 Induction Variables, Interval Identification, Natural Loop Identification,
1086 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1087 <dd> This directory contains the source code for the LLVM to LLVM program
1088 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1089 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1090 Elimination, and many others.</dd>
1092 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1093 <dd> This directory contains files that describe various target architectures
1094 for code generation. For example, the <tt>llvm/lib/Target/SparcV9</tt>
1095 directory holds the Sparc machine description while
1096 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter</dd>
1098 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1099 <dd> This directory contains the major parts of the code generator: Instruction
1100 Selector, Instruction Scheduling, and Register Allocation.</dd>
1102 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1103 <dd> This directory contains the source level debugger library that makes
1104 it possible to instrument LLVM programs so that a debugger could identify
1105 source code locations at which the program is executing.</dd>
1107 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1108 <dd> This directory contains libraries for executing LLVM bytecode directly
1109 at runtime in both interpreted and JIT compiled fashions.</dd>
1111 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1112 <dd> This directory contains the source code that corresponds to the header
1113 files located in <tt>llvm/include/Support/</tt>.</dd>
1115 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1116 <dd>This directory contains the operating system abstraction layer that
1117 shields LLVM from platform-specific coding.</dd>
1122 <!-- ======================================================================= -->
1123 <div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1124 <div class="doc_text">
1125 <p>This directory contains projects that are not strictly part of LLVM but are
1126 shipped with LLVM. This is also the directory where you should create your own
1127 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1128 to set up your own project. See <tt>llvm/projects/Stacker</tt> for a fully
1129 functional example of a compiler front end.</p>
1132 <!-- ======================================================================= -->
1133 <div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1134 <div class="doc_text">
1136 <p>This directory contains libraries which are compiled into LLVM bytecode and
1137 used when linking programs with the GCC front end. Most of these libraries are
1138 skeleton versions of real libraries; for example, libc is a stripped down
1139 version of glibc.</p>
1141 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1146 <!-- ======================================================================= -->
1147 <div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1148 <div class="doc_text">
1149 <p>This directory contains feature and regression tests and other basic sanity
1150 checks on the LLVM infrastructure. These are intended to run quickly and cover
1151 a lot of territory without being exhaustive.</p>
1154 <!-- ======================================================================= -->
1155 <div class="doc_subsection"><a name="llvmtest"><tt>llvm-test</tt></a></div>
1156 <div class="doc_text">
1157 <p>This is not a directory in the normal llvm module, it is a separate CVS
1158 module that must be checked out (usually to <tt>projects/llvm-test</tt>). This
1159 module contains a comprehensive correctness, performance and benchmarking test
1160 suite for LLVM. It is a separate CVS module because not every LLVM user is
1161 interested in downloading or building such a comprehensive test. For further
1162 details on this test suite, please see the
1163 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1166 <!-- ======================================================================= -->
1167 <div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1168 <div class="doc_text">
1170 <p>The <b>tools</b> directory contains the executables built out of the
1171 libraries above, which form the main part of the user interface. You can
1172 always get help for a tool by typing <tt>tool_name --help</tt>. The
1173 following is a brief introduction to the most important tools. More detailed
1174 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1177 <dt><tt><b>analyze</b></tt></dt>
1178 <dd><tt>analyze</tt> is used to run a specific
1179 analysis on an input LLVM bytecode file and print out the results. It is
1180 primarily useful for debugging analyses, or familiarizing yourself with
1181 what an analysis does.</dd>
1183 <dt><tt><b>bugpoint</b></tt></dt>
1184 <dd><tt>bugpoint</tt> is used to debug
1185 optimization passes or code generation backends by narrowing down the
1186 given test case to the minimum number of passes and/or instructions that
1187 still cause a problem, whether it is a crash or miscompilation. See <a
1188 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1189 on using <tt>bugpoint</tt>.</dd>
1191 <dt><tt><b>llvmc</b></tt></dt>
1192 <dd>The LLVM Compiler Driver. This program can
1193 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1194 pre-processing, translation, optimization, assembly, and linking of programs
1195 all from one command line. <tt>llvmc</tt> also takes care of processing the
1196 dependent libraries found in bytecode. This reduces the need to get the
1197 traditional <tt>-l<name></tt> options right on the command line.</dd>
1199 <dt><tt><b>llvm-ar</b></tt></dt>
1200 <dd>The archiver produces an archive containing
1201 the given LLVM bytecode files, optionally with an index for faster
1204 <dt><tt><b>llvm-as</b></tt></dt>
1205 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1208 <dt><tt><b>llvm-dis</b></tt></dt>
1209 <dd>The disassembler transforms the LLVM bytecode to human readable
1212 <dt><tt><b>llvm-link</b></tt></dt>
1213 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1214 a single program.</dd>
1216 <dt><tt><b>lli</b></tt></dt>
1217 <dd><tt>lli</tt> is the LLVM interpreter, which
1218 can directly execute LLVM bytecode (although very slowly...). In addition
1219 to a simple interpreter, <tt>lli</tt> also has a tracing mode (entered by
1220 specifying <tt>-trace</tt> on the command line). Finally, for
1221 architectures that support it (currently only x86 and Sparc), by default,
1222 <tt>lli</tt> will function as a Just-In-Time compiler (if the
1223 functionality was compiled in), and will execute the code <i>much</i>
1224 faster than the interpreter.</dd>
1226 <dt><tt><b>llc</b></tt></dt>
1227 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1228 translates LLVM bytecode to a SPARC or x86 assembly file, or to C code (with
1229 the -march=c option).</dd>
1231 <dt><tt><b>llvmgcc</b></tt></dt>
1232 <dd><tt>llvmgcc</tt> is a GCC-based C frontend
1233 that has been retargeted to emit LLVM code as the machine code output. It
1234 works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
1235 -o</tt> options that are typically used. The source code for the
1236 <tt>llvmgcc</tt> tool is currently not included in the LLVM CVS tree
1237 because it is quite large and not very interesting.
1240 <dt><tt><b>gccas</b></tt></dt>
1241 <dd>This tool is invoked by the <tt>llvmgcc</tt> frontend as the
1242 "assembler" part of the compiler. This tool actually assembles LLVM
1243 assembly to LLVM bytecode, performs a variety of optimizations, and
1244 outputs LLVM bytecode. Thus when you invoke
1245 <tt>llvmgcc -c x.c -o x.o</tt>, you are causing <tt>gccas</tt> to be
1246 run, which writes the <tt>x.o</tt> file (which is an LLVM bytecode file
1247 that can be disassembled or manipulated just like any other bytecode
1248 file). The command line interface to <tt>gccas</tt> is designed to be
1249 as close as possible to the <b>system</b> `<tt>as</tt>' utility so that
1250 the gcc frontend itself did not have to be modified to interface to
1251 a "weird" assembler.</dd>
1253 <dt><tt><b>gccld</b></tt></dt>
1254 <dd><tt>gccld</tt> links together several LLVM bytecode files into one
1255 bytecode file and does some optimization. It is the linker invoked by
1256 the GCC frontend when multiple .o files need to be linked together.
1257 Like <tt>gccas</tt>, the command line interface of <tt>gccld</tt> is
1258 designed to match the system linker, to aid interfacing with the GCC
1264 <dt><tt><b>opt</b></tt></dt>
1265 <dd><tt>opt</tt> reads LLVM bytecode, applies a
1266 series of LLVM to LLVM transformations (which are specified on the command
1267 line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
1268 command is a good way to get a list of the program transformations
1269 available in LLVM.</dd>
1273 <!-- ======================================================================= -->
1274 <div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1275 <div class="doc_text">
1277 <p>This directory contains utilities for working with LLVM source code, and some
1278 of the utilities are actually required as part of the build process because they
1279 are code generators for parts of LLVM infrastructure.</p>
1282 <dt><tt><b>Burg/</b></tt> <dd><tt>Burg</tt> is an instruction selector
1283 generator -- it builds trees on which it then performs pattern-matching to
1284 select instructions according to the patterns the user has specified. Burg
1285 is currently used in the Sparc V9 backend.<p>
1287 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1288 that finds differences between code that LLC generates and code that LLI
1289 generates. This is a useful tool if you are debugging one of them,
1290 assuming that the other generates correct output. For the full user
1291 manual, run <tt>`perldoc codegen-diff'</tt>.<p>
1293 <dt><tt><b>cvsupdate</b></tt> <dd><tt>cvsupdate</tt> is a script that will
1294 update your CVS tree, but produce a much cleaner and more organized output
1295 than simply running <tt>`cvs -z3 up -dP'</tt> will. For example, it will group
1296 together all the new and updated files and modified files in separate
1297 sections, so you can see at a glance what has changed. If you are at the
1298 top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
1299 preferred way of updating the tree.<p>
1301 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1302 syntax-highlighting files which will work with Emacs and XEmacs editors,
1303 providing syntax highlighting support for LLVM assembly files and TableGen
1304 description files. For information on how to use the syntax files, consult
1305 the <tt>README</tt> file in that directory.<p>
1307 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1308 and outputs all non-generated source files, which is useful if one wishes
1309 to do a lot of development across directories and does not want to
1310 individually find each file. One way to use it is to run, for example:
1311 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1314 <dt><tt><b>llvmgrep</b></tt></dt>
1315 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1316 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1317 line. This is a very efficient way of searching the source base for a
1318 particular regular expression.</dd>
1320 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1321 files in the current directory and then compiles and links the tool that
1322 is the first argument. For example, assuming you are in the directory
1323 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1324 simply running <tt>makellvm llc</tt> will make a build of the current
1325 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1326 causing a re-linking of LLC.<p>
1328 <dt><tt><b>NightlyTest.pl</b></tt> and
1329 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1330 cron script to generate nightly status reports of the functionality of
1331 tools, and the results can be seen by following the appropriate link on
1332 the <a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a>.<p>
1334 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1335 the tool used to generate register descriptions, instruction set
1336 descriptions, and even assemblers from common TableGen description
1339 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1340 syntax-highlighting files which will work with the VIM editor, providing
1341 syntax highlighting support for LLVM assembly files and TableGen
1342 description files. For information on how to use the syntax files, consult
1343 the <tt>README</tt> file in that directory.<p>
1349 <!-- ======================================================================= -->
1350 <div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1351 <div class="doc_text">
1352 <p>This directory contains build scripts and project files for use with
1353 Visual C++. This allows developers on Windows to build LLVM without the need
1354 for cygwin. The contents of this directory should be considered experimental
1358 <!-- *********************************************************************** -->
1359 <div class="doc_section">
1360 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1362 <!-- *********************************************************************** -->
1364 <div class="doc_text">
1367 <li>First, create a simple C file, name it 'hello.c':
1369 #include <stdio.h>
1371 printf("hello world\n");
1376 <li><p>Next, compile the C file into a LLVM bytecode file:</p>
1377 <p><tt>% llvmgcc hello.c -o hello</tt></p>
1379 <p>Note that you should have already built the tools and they have to be
1380 in your path, at least <tt>gccas</tt> and <tt>gccld</tt>.</p>
1382 <p>This will create two result files: <tt>hello</tt> and
1383 <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
1384 corresponds the the compiled program and the library facilities that it
1385 required. <tt>hello</tt> is a simple shell script that runs the bytecode
1386 file with <tt>lli</tt>, making the result directly executable. Note that
1387 all LLVM optimizations are enabled by default, so there is no need for a
1388 "-O3" switch.</p></li>
1390 <li><p>Run the program. To make sure the program ran, execute one of the
1391 following commands:</p>
1393 <p><tt>% ./hello</tt></p>
1397 <p><tt>% lli hello.bc</tt></p></li>
1399 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1402 <p><tt>% llvm-dis < hello.bc | less</tt><p></li>
1404 <li><p>Compile the program to native assembly using the LLC code
1407 <p><tt>% llc hello.bc -o hello.s</tt></p>
1409 <li><p>Assemble the native assembly language file into a program:</p>
1411 <p><b>Solaris:</b><tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native</tt></p>
1412 <p><b>Others:</b><tt>% gcc hello.s -o hello.native</tt></p>
1414 <li><p>Execute the native code program:</p>
1416 <p><tt>% ./hello.native</tt></p></li>
1422 <!-- *********************************************************************** -->
1423 <div class="doc_section">
1424 <a name="problems">Common Problems</a>
1426 <!-- *********************************************************************** -->
1428 <div class="doc_text">
1430 <p>If you are having problems building or using LLVM, or if you have any other
1431 general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1432 Asked Questions</a> page.</p>
1436 <!-- *********************************************************************** -->
1437 <div class="doc_section">
1438 <a name="links">Links</a>
1440 <!-- *********************************************************************** -->
1442 <div class="doc_text">
1444 <p>This document is just an <b>introduction</b> to how to use LLVM to do
1445 some simple things... there are many more interesting and complicated things
1446 that you can do that aren't documented here (but we'll gladly accept a patch
1447 if you want to write something up!). For more information about LLVM, check
1451 <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
1452 <li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
1453 <li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project
1454 that Uses LLVM</a></li>
1459 <!-- *********************************************************************** -->
1463 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
1464 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
1465 <a href="http://validator.w3.org/check/referer"><img
1466 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
1468 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1469 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1470 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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