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11 <div class="doc_title">
12 Getting Started with the LLVM System
16 <li><a href="#overview">Overview</a>
17 <li><a href="#quickstart">Getting Started Quickly (A Summary)</a>
18 <li><a href="#requirements">Requirements</a>
20 <li><a href="#hardware">Hardware</a>
21 <li><a href="#software">Software</a>
22 <li><a href="#brokengcc">Broken versions of GCC</a>
25 <li><a href="#starting">Getting Started with LLVM</a>
27 <li><a href="#terminology">Terminology and Notation</a>
28 <li><a href="#environment">Setting Up Your Environment</a>
29 <li><a href="#unpack">Unpacking the LLVM Archives</a>
30 <li><a href="#checkout">Checkout LLVM from CVS</a>
31 <li><a href="#installcf">Install the GCC Front End</a>
32 <li><a href="#config">Local LLVM Configuration</a>
33 <li><a href="#compile">Compiling the LLVM Suite Source Code</a>
34 <li><a href="#objfiles">The Location of LLVM Object Files</a>
35 <li><a href="#optionalconfig">Optional Configuration Items</a>
38 <li><a href="#layout">Program layout</a>
40 <li><a href="#cvsdir"><tt>CVS</tt> directories</a>
41 <li><a href="#examples"><tt>llvm/examples</tt></a>
42 <li><a href="#include"><tt>llvm/include</tt></a>
43 <li><a href="#lib"><tt>llvm/lib</tt></a>
44 <li><a href="#projects"><tt>llvm/projects</tt></a>
45 <li><a href="#runtime"><tt>llvm/runtime</tt></a>
46 <li><a href="#test"><tt>llvm/test</tt></a>
47 <li><a href="#llvmtest"><tt>llvm-test</tt></a>
48 <li><a href="#tools"><tt>llvm/tools</tt></a>
49 <li><a href="#utils"><tt>llvm/utils</tt></a>
50 <li><a href="#win32"><tt>llvm/win32</tt></a>
53 <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
54 <li><a href="#problems">Common Problems</a>
55 <li><a href="#links">Links</a>
58 <div class="doc_author">
60 <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
61 <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
62 <a href="http://misha.brukman.net">Misha Brukman</a>,
63 <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and
64 <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>.
69 <!-- *********************************************************************** -->
70 <div class="doc_section">
71 <a name="overview"><b>Overview</b></a>
73 <!-- *********************************************************************** -->
75 <div class="doc_text">
77 <p>Welcome to LLVM! In order to get started, you first need to know some
78 basic information.</p>
80 <p>First, LLVM comes in two pieces. The first piece is the LLVM suite. This
81 contains all of the tools, libraries, and header files needed to use the low
82 level virtual machine. It contains an assembler, disassembler, bytecode
83 analyzer, and bytecode optimizer. It also contains a test suite that can be
84 used to test the LLVM tools and the GCC front end.</p>
86 <p>The second piece is the GCC front end. This component provides a version of
87 GCC that compiles C and C++ code into LLVM bytecode. Currently, the GCC front
88 end is a modified version of GCC 3.4 (we track the GCC 3.4 development). Once
89 compiled into LLVM bytecode, a program can be manipulated with the LLVM tools
90 from the LLVM suite.</p>
93 There is a third, optional piece called llvm-test. It is a suite of programs
94 with a testing harness that can be used to further test LLVM's functionality
100 <!-- *********************************************************************** -->
101 <div class="doc_section">
102 <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
104 <!-- *********************************************************************** -->
106 <div class="doc_text">
108 <p>Here's the short story for getting up and running quickly with LLVM:</p>
111 <li>Read the documentation.</li>
112 <li>Read the documentation.</li>
113 <li>Remember that you were warned twice about reading the documentation.</li>
114 <li>Install the GCC front end if you intend to compile C or C++:
116 <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li>
117 <li><tt>gunzip --stdout cfrontend.<i>platform</i>.tar.gz | tar -xvf -</tt>
119 <li><tt>cd cfrontend/<i>platform</i><br>
120 ./fixheaders</tt></li>
121 <li>Add the cfrontend's "bin" directory to your PATH variable</li>
124 <li>Get the LLVM Source Code
126 <li>With the distributed files (or use <a href="#checkout">CVS</a>):
128 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
129 <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
134 <li><b>[Optional]</b> Get the Test Suite Source Code
136 <li>With the distributed files (or use <a href="#checkout">CVS</a>):
138 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
139 <li><tt>cd llvm/projects</tt>
140 <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
146 <li>Configure the LLVM Build Environment
148 <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
149 <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br>
153 <li><tt>--prefix=<i>directory</i></tt>
154 <p>Specify for <i>directory</i> the full pathname of where you
155 want the LLVM tools and libraries to be installed (default
156 <tt>/usr/local</tt>).</p></li>
157 <li><tt>--with-llvmgccdir=<i>directory</i></tt>
158 <p>Optionally, specify for <i>directory</i> the full pathname of the
159 C/C++ FrontEnd installation to use with this LLVM configuration. If
160 not specified, the PATH will be searched.</p></li>
161 <li><tt>--enable-spec2000=<i>directory</i></tt>
162 <p>Enable the SPEC2000 benchmarks for testing. The SPEC2000
163 benchmarks should be available in
164 <tt><i>directory</i></tt>.</p></li>
168 <li>Build the LLVM Suite:
170 <li><tt>gmake -k |& tee gnumake.out
171 # this is csh or tcsh syntax</tt></li>
172 <li>If you get an "internal compiler error (ICE)" see <a href="#brokengcc">below</a>.</li>
177 <p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
178 detailed information on configuring and compiling LLVM. See <a
179 href="#environment">Setting Up Your Environment</a> for tips that simplify
180 working with the GCC front end and LLVM tools. Go to <a href="#layout">Program
181 Layout</a> to learn about the layout of the source code tree.</p>
185 <!-- *********************************************************************** -->
186 <div class="doc_section">
187 <a name="requirements"><b>Requirements</b></a>
189 <!-- *********************************************************************** -->
191 <div class="doc_text">
193 <p>Before you begin to use the LLVM system, review the requirements given below.
194 This may save you some trouble by knowing ahead of time what hardware and
195 software you will need.</p>
199 <!-- ======================================================================= -->
200 <div class="doc_subsection">
201 <a name="hardware"><b>Hardware</b></a>
204 <div class="doc_text">
206 <p>LLVM is known to work on the following platforms:</p>
208 <table cellpadding="3">
216 <td>x86<sup><a href="#pf_1">1</a></sup></td>
221 <td>V9 (Ultrasparc)</td>
226 <td>x86<sup><a href="#pf_1">1</a></sup></td>
230 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
235 <td>Cygwin/Win32</td>
236 <td>x86<sup><a href="#pf_1">1</a></sup></td>
237 <td>GCC 3.4.X, binutils 2.15</td>
241 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a></sup></td>
242 <td>GCC 3.4.X, binutils 2.15</td>
246 <td>amd64<sup><a href="#pf_3">3</a></sup></td>
251 <p>LLVM has partial support for the following platforms:</p>
261 <td>x86<sup><a href="#pf_1">1</a></sup></td>
262 <td>Visual Studio .NET<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
264 <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
269 <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
277 <div class="doc_notes">
279 <li><a name="pf_1">Code generation supported for Pentium processors and
281 <li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
282 <li><a name="pf_3">No native code generation</a></li>
283 <li><a name="pf_4">Build is not complete: one or more tools don't link</a></li>
284 <li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
285 <li><a name="pf_6">The port is done using the MSYS shell.
286 <a href="http://www.mingw.org/MinGWiki/">Download</a> and install
287 bison (excl. M4.exe) and flex in that order. Build binutils-2.15 from source,
288 if necessary. If you need to create a library for an MS DLL, do the following:
290 <li><tt>pexports /C/WINNT/SYSTEM32/file.dll | sed "s/^_//" >
291 /C/MinGW/lib/file.def</tt></li>
292 <li>Edit file and append @<ordinal> to the missing function name</li>
293 <li><tt>dlltool.exe -k -d /C/MinGW/lib/file.def -l
294 /C/MinGW/lib/libfile.a.</tt></li>
299 <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
300 mode, depending on the system (because of all the debug info), and the libraries
301 appear in more than one of the tools that get linked, so there is some
302 duplication. If you do not need many of the tools and you are space-conscious,
303 you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
304 build requires considerably less space.</p>
306 <p>The LLVM suite <i>may</i> compile on other platforms, but it is not
307 guaranteed to do so. If compilation is successful, the LLVM utilities should be
308 able to assemble, disassemble, analyze, and optimize LLVM bytecode. Code
309 generation should work as well, although the generated native code may not work
310 on your platform.</p>
312 <p>The GCC front end is not very portable at the moment. If you want to get it
313 to work on another platform, you can download a copy of the source and <a
314 href="CFEBuildInstrs.html">try to compile it</a> on your platform.</p>
318 <!-- ======================================================================= -->
319 <div class="doc_subsection"><a name="software"><b>Software</b></a></div>
320 <div class="doc_text">
321 <p>Compiling LLVM requires that you have several software packages
322 installed. The table below lists those required packages. The Package column
323 is the usual name for the software package that LLVM depends on. The Version
324 column provides "known to work" versions of the package. The Notes column
325 describes how LLVM uses the package and provides other details.</p>
327 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
330 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
331 <td>3.79, 3.79.1</td>
332 <td>Makefile/build processor</td>
336 <td><a href="http://gcc.gnu.org">GCC</a></td>
338 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
342 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
344 <td>LEX compiler</td>
348 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
350 <td>YACC compiler</td>
354 <td><a href="https://www.cvshome.org/downloads.html">CVS</a></td>
356 <td>CVS access to LLVM<sup><a href="#sf2">2</a></sup></td>
360 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
362 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
366 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
368 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
372 <td><a href="http://expect.nist.gov/">expect</a></td>
374 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
378 <td><a href="http://www.perl.com/download.csp">perl</a></td>
380 <td>Nightly tester, utilities</td>
384 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
386 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
390 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
392 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
396 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
398 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
402 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
404 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
410 <div class="doc_notes">
412 <li><a name="sf3">Only the C and C++ languages are needed so there's no
413 need to build the other languages for LLVM's purposes.</a> See
414 <a href="#brokengcc">below</a> for specific version info.</li>
415 <li><a name="sf2">You only need CVS if you intend to build from the
416 latest LLVM sources. If you're working from a release distribution, you
417 don't need CVS.</a></li>
418 <li><a name="sf3">Only needed if you want to run the automated test
419 suite in the <tt>llvm/test</tt> directory.</a></li>
420 <li><a name="sf4">If you want to make changes to the configure scripts,
421 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
422 or higher). You will also need automake (1.9.2). We only use aclocal
423 from that package.</a></li>
427 <p>Additionally, your compilation host is expected to have the usual
428 plethora of Unix utilities. Specifically:</p>
430 <li><b>ar</b> - archive library builder</li>
431 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
432 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
433 <li><b>chmod</b> - change permissions on a file</li>
434 <li><b>cat</b> - output concatenation utility</li>
435 <li><b>cp</b> - copy files</li>
436 <li><b>date</b> - print the current date/time </li>
437 <li><b>echo</b> - print to standard output</li>
438 <li><b>egrep</b> - extended regular expression search utility</li>
439 <li><b>etags</b> - C/C++ tag file creator for vim/emacs</li>
440 <li><b>find</b> - find files/dirs in a file system</li>
441 <li><b>grep</b> - regular expression search utility</li>
442 <li><b>gzip*</b> - gzip command for distribution generation</li>
443 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
444 <li><b>install</b> - install directories/files </li>
445 <li><b>mkdir</b> - create a directory</li>
446 <li><b>mv</b> - move (rename) files</li>
447 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
448 <li><b>rm</b> - remove (delete) files and directories</li>
449 <li><b>sed</b> - stream editor for transforming output</li>
450 <li><b>sh</b> - Bourne shell for make build scripts</li>
451 <li><b>tar</b> - tape archive for distribution generation</li>
452 <li><b>test</b> - test things in file system</li>
453 <li><b>unzip*</b> - unzip command for distribution checking</li>
454 <li><b>zip*</b> - zip command for distribution generation</li>
458 <!-- ======================================================================= -->
459 <div class="doc_subsection">
460 <a name="brokengcc">Broken versions of GCC</a>
463 <div class="doc_text">
465 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
466 bugs in the compiler. In particular, several versions of GCC crash when trying
467 to compile LLVM. We routinely use GCC 3.3.3 and GCC 3.4.0 and have had success
468 with them. Other versions of GCC will probably work as well. GCC versions listed
469 here are known to not work. If you are using one of these versions, please try
470 to upgrade your GCC to something more recent. If you run into a problem with a
471 version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
472 us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
473 of GCC you are using.
476 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
477 problems in the STL that effectively prevent it from compiling LLVM.
480 <p><b>GCC 3.2.2</b>: This version of GCC fails to compile LLVM.</p>
482 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
483 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
484 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
489 <!-- *********************************************************************** -->
490 <div class="doc_section">
491 <a name="starting"><b>Getting Started with LLVM</b></a>
493 <!-- *********************************************************************** -->
495 <div class="doc_text">
497 <p>The remainder of this guide is meant to get you up and running with
498 LLVM and to give you some basic information about the LLVM environment.</p>
500 <p>The later sections of this guide describe the <a
501 href="#layout">general layout</a> of the the LLVM source tree, a <a
502 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
503 href="#links">links</a> to find more information about LLVM or to get
507 <!-- ======================================================================= -->
508 <div class="doc_subsection">
509 <a name="terminology">Terminology and Notation</a>
512 <div class="doc_text">
514 <p>Throughout this manual, the following names are used to denote paths
515 specific to the local system and working environment. <i>These are not
516 environment variables you need to set but just strings used in the rest
517 of this document below</i>. In any of the examples below, simply replace
518 each of these names with the appropriate pathname on your local system.
519 All these paths are absolute:</p>
524 This is the top level directory of the LLVM source tree.
529 This is the top level directory of the LLVM object tree (i.e. the
530 tree where object files and compiled programs will be placed. It
531 can be the same as SRC_ROOT).
536 This is where the LLVM GCC Front End is installed.
538 For the pre-built GCC front end binaries, the LLVMGCCDIR is
539 <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
544 <!-- ======================================================================= -->
545 <div class="doc_subsection">
546 <a name="environment">Setting Up Your Environment</a>
549 <div class="doc_text">
552 In order to compile and use LLVM, you may need to set some environment
556 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bytecode/libs</tt></dt>
557 <dd>[Optional] This environment variable helps LLVM linking tools find the
558 locations of your bytecode libraries. It is provided only a
559 convenience since you can specify the paths using the -L options of the
560 tools and the C/C++ front-end will use the bytecode files installed in its
561 <tt>lib</tt> directory.</dd>
566 <!-- ======================================================================= -->
567 <div class="doc_subsection">
568 <a name="unpack">Unpacking the LLVM Archives</a>
571 <div class="doc_text">
574 If you have the LLVM distribution, you will need to unpack it before you
575 can begin to compile it. LLVM is distributed as a set of two files: the LLVM
576 suite and the LLVM GCC front end compiled for your platform. There is an
577 additional test suite that is optional. Each file is a TAR archive that is
578 compressed with the gzip program.
581 <p>The files are as follows, with <em>x.y</em> marking the version number:
583 <dt><tt>llvm-x.y.tar.gz</tt></dt>
584 <dd>Source release for the LLVM libraries and tools.<br/></dd>
586 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
587 <dd>Source release for the LLVM test suite.</dd>
589 <dt><tt>cfrontend-x.y.source.tar.gz</tt></dt>
590 <dd>Source release of the GCC front end.<br/></dd>
592 <dt><tt>cfrontend-x.y.sparc-sun-solaris2.8.tar.gz</tt></dt>
593 <dd>Binary release of the GCC front end for Solaris/Sparc.
596 <dt><tt>cfrontend-x.y.i686-redhat-linux-gnu.tar.gz</tt></dt>
597 <dd>Binary release of the GCC front end for Linux/x86.<br/></dd>
599 <dt><tt>cfrontend-x.y.i386-unknown-freebsd5.1.tar.gz</tt></dt>
600 <dd>Binary release of the GCC front end for FreeBSD/x86.<br/></dd>
602 <dt><tt>cfrontend-x.y.powerpc-apple-darwin7.6.0.tar.gz</tt></dt>
603 <dd>Binary release of the GCC front end for MacOS X/PPC.<br/></dd>
608 <!-- ======================================================================= -->
609 <div class="doc_subsection">
610 <a name="checkout">Checkout LLVM from CVS</a>
613 <div class="doc_text">
615 <p>If you have access to our CVS repository, you can get a fresh copy of
616 the entire source code. All you need to do is check it out from CVS as
620 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
621 <li><tt>cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
622 <li>Hit the return key when prompted for the password.
623 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co
627 <p>This will create an '<tt>llvm</tt>' directory in the current
628 directory and fully populate it with the LLVM source code, Makefiles,
629 test directories, and local copies of documentation files.</p>
631 <p>If you want to get a specific release (as opposed to the most recent
632 revision), you can specify a label. The following releases have the following
636 <li>Release 1.4: <b>RELEASE_14</b></li>
637 <li>Release 1.3: <b>RELEASE_13</b></li>
638 <li>Release 1.2: <b>RELEASE_12</b></li>
639 <li>Release 1.1: <b>RELEASE_11</b></li>
640 <li>Release 1.0: <b>RELEASE_1</b></li>
643 <p>If you would like to get the LLVM test suite (a separate package as of 1.4),
644 you get it from the CVS repository:</p>
647 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-test
649 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
650 configured by the LLVM configure script as well as automatically updated when
651 you run <tt>cvs update</tt>.</p>
653 <p>If you would like to get the GCC front end source code, you can also get it
654 from the CVS repository:</p>
657 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-gcc
660 <p>Please note that you must follow <a href="CFEBuildInstrs.html">these
661 instructions</a> to successfully build the LLVM GCC front-end.</p>
665 <!-- ======================================================================= -->
666 <div class="doc_subsubsection">
667 <a name="mirrors">LLVM CVS Mirrors</a>
670 <div class="doc_text">
672 <p>If the main CVS server is overloaded or inaccessible, you can try one of
673 these user-hosted mirrors:</p>
676 <li><a href="http://llvm.x10sys.com/">Mirror hosted by eXtensible Systems
681 <!-- ======================================================================= -->
682 <div class="doc_subsection">
683 <a name="installcf">Install the GCC Front End</a>
686 <div class="doc_text">
688 <p>Before configuring and compiling the LLVM suite, you need to extract the LLVM
689 GCC front end from the binary distribution. It is used for building the
690 bytecode libraries later used by the GCC front end for linking programs, and its
691 location must be specified when the LLVM suite is configured.</p>
693 <p>To install the GCC front end, do the following:</p>
696 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
697 <li><tt>gunzip --stdout cfrontend-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
701 <p>Next, you will need to fix your system header files:</p>
703 <p><tt>cd cfrontend/<i>platform</i><br>
704 ./fixheaders</tt></p>
706 <p>The binary versions of the GCC front end may not suit all of your needs. For
707 example, the binary distribution may include an old version of a system header
708 file, not "fix" a header file that needs to be fixed for GCC, or it may be
709 linked with libraries not available on your system.</p>
711 <p>In cases like these, you may want to try <a
712 href="CFEBuildInstrs.html">building the GCC front end from source.</a> This is
713 not for the faint of heart, so be forewarned.</p>
717 <!-- ======================================================================= -->
718 <div class="doc_subsection">
719 <a name="config">Local LLVM Configuration</a>
722 <div class="doc_text">
724 <p>Once checked out from the CVS repository, the LLVM suite source code must be
725 configured via the <tt>configure</tt> script. This script sets variables in the
726 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
727 <tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
728 the Makefiles needed to begin building LLVM.</p>
730 <p>The following environment variables are used by the <tt>configure</tt>
731 script to configure the build system:</p>
734 <tr><th>Variable</th><th>Purpose</th></tr>
737 <td>Tells <tt>configure</tt> which C compiler to use. By default,
738 <tt>configure</tt> will look for the first GCC C compiler in
739 <tt>PATH</tt>. Use this variable to override
740 <tt>configure</tt>'s default behavior.</td>
744 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
745 <tt>configure</tt> will look for the first GCC C++ compiler in
746 <tt>PATH</tt>. Use this variable to override
747 <tt>configure</tt>'s default behavior.</td>
751 <p>The following options can be used to set or enable LLVM specific options:</p>
754 <dt><i>--with-llvmgccdir</i></dt>
755 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
756 The value of this option should specify the full pathname of the C/C++ Front
757 End to be used. If this option is not provided, the PATH will be searched for
758 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
759 be inferred from the path found. If the option is not given, and no llvm-gcc
760 can be found in the path then a warning will be produced by
761 <tt>configure</tt> indicating this situation. LLVM may still be built with
762 the <tt>tools-only</tt> target but attempting to build the runtime libraries
763 will fail as these libraries require llvm-gcc and llvm-g++. See
764 <a href="#installcf">Install the GCC Front End</a> for details on installing
765 the C/C++ Front End. See
766 <a href="CFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
767 for details on building the C/C++ Front End.</dd>
768 <dt><i>--with-tclinclude</i></dt>
769 <dd>Path to the tcl include directory under which the <tt>tclsh</tt> can be
770 found. Use this if you have multiple tcl installations on your machine and you
771 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
772 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
773 option, the LLVM configure script will search for tcl 8.4 and 8.3 releases.
776 <dt><i>--enable-optimized</i></dt>
778 Enables optimized compilation by default (debugging symbols are removed
779 and GCC optimization flags are enabled). The default is to use an
780 unoptimized build (also known as a debug build).
783 <dt><i>--enable-jit</i></dt>
785 Compile the Just In Time (JIT) compiler functionality. This is not
787 on all platforms. The default is dependent on platform, so it is best
788 to explicitly enable it if you want it.
791 <dt><i>--enable-doxygen</i></dt>
792 <dd>Look for the doxygen program and enable construction of doxygen based
793 documentation from the source code. This is disabled by default because
794 generating the documentation can take a long time and producess 100s of
795 megabytes of output.</dd>
798 <p>To configure LLVM, follow these steps:</p>
801 <li>Change directory into the object root directory:
803 <tt>cd <i>OBJ_ROOT</i></tt>
806 <li>Run the <tt>configure</tt> script located in the LLVM source tree:
808 <tt><i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</tt>
814 <!-- ======================================================================= -->
815 <div class="doc_subsection">
816 <a name="compile">Compiling the LLVM Suite Source Code</a>
819 <div class="doc_text">
821 <p>Once you have configured LLVM, you can build it. There are three types of
827 These builds are the default when one types <tt>gmake</tt> (unless the
828 <tt>--enable-optimized</tt> option was used during configuration). The
829 build system will compile the tools and libraries with debugging
833 <dt>Release (Optimized) Builds
835 These builds are enabled with the <tt>--enable-optimized</tt> option to
836 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
837 <tt>gmake</tt> command line. For these builds, the build system will
838 compile the tools and libraries with GCC optimizations enabled and strip
839 debugging information from the libraries and executables it generates.
844 These builds are for use with profiling. They compile profiling
845 information into the code for use with programs like <tt>gprof</tt>.
846 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
847 on the <tt>gmake</tt> command line.
850 <p>Once you have LLVM configured, you can build it by entering the
851 <i>OBJ_ROOT</i> directory and issuing the following command:</p>
853 <p><tt>gmake</tt></p>
855 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
856 are using a version of GCC that is known not to compile LLVM.</p>
859 If you have multiple processors in your machine, you may wish to use some of
860 the parallel build options provided by GNU Make. For example, you could use the
863 <p><tt>gmake -j2</tt></p>
865 <p>There are several special targets which are useful when working with the LLVM
869 <dt><tt>gmake clean</tt>
871 Removes all files generated by the build. This includes object files,
872 generated C/C++ files, libraries, and executables.
875 <dt><tt>gmake dist-clean</tt>
877 Removes everything that <tt>gmake clean</tt> does, but also removes files
878 generated by <tt>configure</tt>. It attempts to return the source tree to the
879 original state in which it was shipped.
882 <dt><tt>gmake install</tt>
884 Installs LLVM header files, libraries, tools, and documentation in a
886 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
887 defaults to <tt>/usr/local</tt>.
890 <dt><tt>gmake -C runtime install-bytecode</tt>
892 Assuming you built LLVM into $OBJDIR, when this command is run, it will
893 install bytecode libraries into the GCC front end's bytecode library
894 directory. If you need to update your bytecode libraries,
895 this is the target to use once you've built them.
899 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
900 details on these <tt>make</tt> targets and descriptions of other targets
903 <p>It is also possible to override default values from <tt>configure</tt> by
904 declaring variables on the command line. The following are some examples:</p>
907 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
909 Perform a Release (Optimized) build.
912 <dt><tt>gmake ENABLE_PROFILING=1</tt>
914 Perform a Profiling build.
917 <dt><tt>gmake VERBOSE=1</tt>
919 Print what <tt>gmake</tt> is doing on standard output.
922 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
923 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
924 the standard output. This also implies <tt>VERBOSE=1</tt>.
928 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
929 it and any subdirectories that it contains. Entering any directory inside the
930 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
931 that directory that is out of date.</p>
935 <!-- ======================================================================= -->
936 <div class="doc_subsection">
937 <a name="objfiles">The Location of LLVM Object Files</a>
940 <div class="doc_text">
942 <p>The LLVM build system is capable of sharing a single LLVM source tree among
943 several LLVM builds. Hence, it is possible to build LLVM for several different
944 platforms or configurations using the same source tree.</p>
946 <p>This is accomplished in the typical autoconf manner:</p>
949 <li><p>Change directory to where the LLVM object files should live:</p>
951 <p><tt>cd <i>OBJ_ROOT</i></tt></p></li>
953 <li><p>Run the <tt>configure</tt> script found in the LLVM source
956 <p><tt><i>SRC_ROOT</i>/configure</tt></p></li>
959 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
960 named after the build type:</p>
967 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
969 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
977 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
979 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
987 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
989 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
995 <!-- ======================================================================= -->
996 <div class="doc_subsection">
997 <a name="optionalconfig">Optional Configuration Items</a>
1000 <div class="doc_text">
1003 If you're running on a Linux system that supports the "<a
1004 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">
1006 module, and you have root access on the system, you can set your system up to
1007 execute LLVM bytecode files directly. To do this, use commands like this (the
1008 first command may not be required if you are already using the module):</p>
1010 <div class="doc_code">
1012 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1013 $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
1014 $ chmod u+x hello.bc (if needed)
1020 This allows you to execute LLVM bytecode files directly. Thanks to Jack
1021 Cummings for pointing this out!
1027 <!-- *********************************************************************** -->
1028 <div class="doc_section">
1029 <a name="layout"><b>Program Layout</b></a>
1031 <!-- *********************************************************************** -->
1033 <div class="doc_text">
1035 <p>One useful source of information about the LLVM source base is the LLVM <a
1036 href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1037 href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>.
1038 The following is a brief introduction to code layout:</p>
1042 <!-- ======================================================================= -->
1043 <div class="doc_subsection"><a name="cvsdir"><tt>CVS</tt> directories</a></div>
1044 <div class="doc_text">
1045 <p>Every directory checked out of CVS will contain a <tt>CVS</tt> directory; for
1046 the most part these can just be ignored.</p>
1049 <!-- ======================================================================= -->
1050 <div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1051 <div class="doc_text">
1052 <p>This directory contains some simple examples of how to use the LLVM IR and
1056 <!-- ======================================================================= -->
1057 <div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1058 <div class="doc_text">
1060 <p>This directory contains public header files exported from the LLVM
1061 library. The three main subdirectories of this directory are:</p>
1064 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1065 <dd>This directory contains all of the LLVM specific header files. This
1066 directory also has subdirectories for different portions of LLVM:
1067 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1070 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1071 <dd>This directory contains generic support libraries that are provided with
1072 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1073 and a Command Line option processing library store their header files here.
1076 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1077 <dd>This directory contains header files configured by the <tt>configure</tt>
1078 script. They wrap "standard" UNIX and C header files. Source code can
1079 include these header files which automatically take care of the conditional
1080 #includes that the <tt>configure</tt> script generates.</dd>
1084 <!-- ======================================================================= -->
1085 <div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1086 <div class="doc_text">
1088 <p>This directory contains most of the source files of the LLVM system. In LLVM,
1089 almost all code exists in libraries, making it very easy to share code among the
1090 different <a href="#tools">tools</a>.</p>
1093 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1094 <dd> This directory holds the core LLVM source files that implement core
1095 classes like Instruction and BasicBlock.</dd>
1097 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1098 <dd>This directory holds the source code for the LLVM assembly language parser
1101 <dt><tt><b>llvm/lib/ByteCode/</b></tt></dt>
1102 <dd>This directory holds code for reading and write LLVM bytecode.</dd>
1104 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1105 different program analyses, such as Dominator Information, Call Graphs,
1106 Induction Variables, Interval Identification, Natural Loop Identification,
1109 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1110 <dd> This directory contains the source code for the LLVM to LLVM program
1111 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1112 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1113 Elimination, and many others.</dd>
1115 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1116 <dd> This directory contains files that describe various target architectures
1117 for code generation. For example, the <tt>llvm/lib/Target/SparcV9</tt>
1118 directory holds the Sparc machine description while
1119 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter</dd>
1121 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1122 <dd> This directory contains the major parts of the code generator: Instruction
1123 Selector, Instruction Scheduling, and Register Allocation.</dd>
1125 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1126 <dd> This directory contains the source level debugger library that makes
1127 it possible to instrument LLVM programs so that a debugger could identify
1128 source code locations at which the program is executing.</dd>
1130 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1131 <dd> This directory contains libraries for executing LLVM bytecode directly
1132 at runtime in both interpreted and JIT compiled fashions.</dd>
1134 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1135 <dd> This directory contains the source code that corresponds to the header
1136 files located in <tt>llvm/include/Support/</tt>.</dd>
1138 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1139 <dd>This directory contains the operating system abstraction layer that
1140 shields LLVM from platform-specific coding.</dd>
1145 <!-- ======================================================================= -->
1146 <div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1147 <div class="doc_text">
1148 <p>This directory contains projects that are not strictly part of LLVM but are
1149 shipped with LLVM. This is also the directory where you should create your own
1150 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1151 to set up your own project. See <tt>llvm/projects/Stacker</tt> for a fully
1152 functional example of a compiler front end.</p>
1155 <!-- ======================================================================= -->
1156 <div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1157 <div class="doc_text">
1159 <p>This directory contains libraries which are compiled into LLVM bytecode and
1160 used when linking programs with the GCC front end. Most of these libraries are
1161 skeleton versions of real libraries; for example, libc is a stripped down
1162 version of glibc.</p>
1164 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1169 <!-- ======================================================================= -->
1170 <div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1171 <div class="doc_text">
1172 <p>This directory contains feature and regression tests and other basic sanity
1173 checks on the LLVM infrastructure. These are intended to run quickly and cover
1174 a lot of territory without being exhaustive.</p>
1177 <!-- ======================================================================= -->
1178 <div class="doc_subsection"><a name="llvmtest"><tt>llvm-test</tt></a></div>
1179 <div class="doc_text">
1180 <p>This is not a directory in the normal llvm module; it is a separate CVS
1181 module that must be checked out (usually to <tt>projects/llvm-test</tt>). This
1182 module contains a comprehensive correctness, performance, and benchmarking
1184 suite for LLVM. It is a separate CVS module because not every LLVM user is
1185 interested in downloading or building such a comprehensive test. For further
1186 details on this test suite, please see the
1187 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1190 <!-- ======================================================================= -->
1191 <div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1192 <div class="doc_text">
1194 <p>The <b>tools</b> directory contains the executables built out of the
1195 libraries above, which form the main part of the user interface. You can
1196 always get help for a tool by typing <tt>tool_name --help</tt>. The
1197 following is a brief introduction to the most important tools. More detailed
1198 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1201 <dt><tt><b>analyze</b></tt></dt>
1202 <dd><tt>analyze</tt> is used to run a specific
1203 analysis on an input LLVM bytecode file and print out the results. It is
1204 primarily useful for debugging analyses, or familiarizing yourself with
1205 what an analysis does.</dd>
1207 <dt><tt><b>bugpoint</b></tt></dt>
1208 <dd><tt>bugpoint</tt> is used to debug
1209 optimization passes or code generation backends by narrowing down the
1210 given test case to the minimum number of passes and/or instructions that
1211 still cause a problem, whether it is a crash or miscompilation. See <a
1212 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1213 on using <tt>bugpoint</tt>.</dd>
1215 <dt><tt><b>llvmc</b></tt></dt>
1216 <dd>The LLVM Compiler Driver. This program can
1217 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1218 pre-processing, translation, optimization, assembly, and linking of programs
1219 all from one command line. <tt>llvmc</tt> also takes care of processing the
1220 dependent libraries found in bytecode. This reduces the need to get the
1221 traditional <tt>-l<name></tt> options right on the command line. Please
1222 note that this tool is new in 1.4 and considered experimental. It will be
1223 fully supported in 1.5.</dd>
1225 <dt><tt><b>llvm-ar</b></tt></dt>
1226 <dd>The archiver produces an archive containing
1227 the given LLVM bytecode files, optionally with an index for faster
1230 <dt><tt><b>llvm-as</b></tt></dt>
1231 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1234 <dt><tt><b>llvm-dis</b></tt></dt>
1235 <dd>The disassembler transforms the LLVM bytecode to human readable
1238 <dt><tt><b>llvm-ld</b></tt></dt>
1239 <dd><tt>llvm-ld</tt> is very similar to gccld and provides a general purpose
1240 and extensible linker for LLVM. This is the linker invoked by <tt>llvmc</tt>.
1241 It allows optimization modules to be loaded so that language specific
1242 optimizations can be applied at link time. Please note that this tool is new
1243 in LLVM 1.4 and still considered experimental. It will be fully supported in
1246 <dt><tt><b>llvm-link</b></tt></dt>
1247 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1248 a single program.</dd>
1250 <dt><tt><b>lli</b></tt></dt>
1251 <dd><tt>lli</tt> is the LLVM interpreter, which
1252 can directly execute LLVM bytecode (although very slowly...). In addition
1253 to a simple interpreter, <tt>lli</tt> also has a tracing mode (entered by
1254 specifying <tt>-trace</tt> on the command line). Finally, for
1255 architectures that support it (currently x86, Sparc, and PowerPC), by default,
1256 <tt>lli</tt> will function as a Just-In-Time compiler (if the
1257 functionality was compiled in), and will execute the code <i>much</i>
1258 faster than the interpreter.</dd>
1260 <dt><tt><b>llc</b></tt></dt>
1261 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1262 translates LLVM bytecode to a SPARC or x86 assembly file, or to C code (with
1263 the -march=c option).</dd>
1265 <dt><tt><b>llvm-gcc</b></tt></dt>
1266 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend
1267 that has been retargeted to emit LLVM code as the machine code output. It
1268 works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
1269 -o</tt> options that are typically used. The source code for the
1270 <tt>llvm-gcc</tt> tool is currently not included in the LLVM CVS tree
1271 because it is quite large and not very interesting.
1274 <dt><tt><b>gccas</b></tt></dt>
1275 <dd>This tool is invoked by the <tt>llvm-gcc</tt> frontend as the
1276 "assembler" part of the compiler. This tool actually assembles LLVM
1277 assembly to LLVM bytecode, performs a variety of optimizations, and
1278 outputs LLVM bytecode. Thus when you invoke
1279 <tt>llvm-gcc -c x.c -o x.o</tt>, you are causing <tt>gccas</tt> to be
1280 run, which writes the <tt>x.o</tt> file (which is an LLVM bytecode file
1281 that can be disassembled or manipulated just like any other bytecode
1282 file). The command line interface to <tt>gccas</tt> is designed to be
1283 as close as possible to the <b>system</b> `<tt>as</tt>' utility so that
1284 the gcc frontend itself did not have to be modified to interface to
1285 a "weird" assembler.</dd>
1287 <dt><tt><b>gccld</b></tt></dt>
1288 <dd><tt>gccld</tt> links together several LLVM bytecode files into one
1289 bytecode file and does some optimization. It is the linker invoked by
1290 the GCC frontend when multiple .o files need to be linked together.
1291 Like <tt>gccas</tt>, the command line interface of <tt>gccld</tt> is
1292 designed to match the system linker, to aid interfacing with the GCC
1298 <dt><tt><b>opt</b></tt></dt>
1299 <dd><tt>opt</tt> reads LLVM bytecode, applies a
1300 series of LLVM to LLVM transformations (which are specified on the command
1301 line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
1302 command is a good way to get a list of the program transformations
1303 available in LLVM.</dd>
1307 <!-- ======================================================================= -->
1308 <div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1309 <div class="doc_text">
1311 <p>This directory contains utilities for working with LLVM source code, and some
1312 of the utilities are actually required as part of the build process because they
1313 are code generators for parts of LLVM infrastructure.</p>
1316 <dt><tt><b>Burg/</b></tt> <dd><tt>Burg</tt> is an instruction selector
1317 generator -- it builds trees on which it then performs pattern-matching to
1318 select instructions according to the patterns the user has specified. Burg
1319 is currently used in the Sparc V9 backend.<p>
1321 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1322 that finds differences between code that LLC generates and code that LLI
1323 generates. This is a useful tool if you are debugging one of them,
1324 assuming that the other generates correct output. For the full user
1325 manual, run <tt>`perldoc codegen-diff'</tt>.<p>
1327 <dt><tt><b>cvsupdate</b></tt> <dd><tt>cvsupdate</tt> is a script that will
1328 update your CVS tree, but produce a much cleaner and more organized output
1329 than simply running <tt>`cvs -z3 up -dP'</tt> will. For example, it will group
1330 together all the new and updated files and modified files in separate
1331 sections, so you can see at a glance what has changed. If you are at the
1332 top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
1333 preferred way of updating the tree.<p>
1335 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1336 syntax-highlighting files which will work with Emacs and XEmacs editors,
1337 providing syntax highlighting support for LLVM assembly files and TableGen
1338 description files. For information on how to use the syntax files, consult
1339 the <tt>README</tt> file in that directory.<p>
1341 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1342 and outputs all non-generated source files, which is useful if one wishes
1343 to do a lot of development across directories and does not want to
1344 individually find each file. One way to use it is to run, for example:
1345 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1348 <dt><tt><b>llvmgrep</b></tt></dt>
1349 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1350 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1351 line. This is a very efficient way of searching the source base for a
1352 particular regular expression.</dd>
1354 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1355 files in the current directory and then compiles and links the tool that
1356 is the first argument. For example, assuming you are in the directory
1357 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1358 simply running <tt>makellvm llc</tt> will make a build of the current
1359 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1360 causing a re-linking of LLC.<p>
1362 <dt><tt><b>NightlyTest.pl</b></tt> and
1363 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1364 cron script to generate nightly status reports of the functionality of
1365 tools, and the results can be seen by following the appropriate link on
1366 the <a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a>.<p>
1368 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1369 the tool used to generate register descriptions, instruction set
1370 descriptions, and even assemblers from common TableGen description
1373 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1374 syntax-highlighting files which will work with the VIM editor, providing
1375 syntax highlighting support for LLVM assembly files and TableGen
1376 description files. For information on how to use the syntax files, consult
1377 the <tt>README</tt> file in that directory.<p>
1383 <!-- ======================================================================= -->
1384 <div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1385 <div class="doc_text">
1386 <p>This directory contains build scripts and project files for use with
1387 Visual C++. This allows developers on Windows to build LLVM without the need
1388 for Cygwin. The contents of this directory should be considered experimental
1392 <!-- *********************************************************************** -->
1393 <div class="doc_section">
1394 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1396 <!-- *********************************************************************** -->
1398 <div class="doc_text">
1401 <li>First, create a simple C file, name it 'hello.c':
1403 #include <stdio.h>
1405 printf("hello world\n");
1410 <li><p>Next, compile the C file into a LLVM bytecode file:</p>
1411 <p><tt>% llvm-gcc hello.c -o hello</tt></p>
1413 <p>Note that you should have already built the tools and they have to be
1414 in your path, at least <tt>gccas</tt> and <tt>gccld</tt>.</p>
1416 <p>This will create two result files: <tt>hello</tt> and
1417 <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
1418 corresponds the the compiled program and the library facilities that it
1419 required. <tt>hello</tt> is a simple shell script that runs the bytecode
1420 file with <tt>lli</tt>, making the result directly executable. Note that
1421 all LLVM optimizations are enabled by default, so there is no need for a
1422 "-O3" switch.</p></li>
1424 <li><p>Run the program. To make sure the program ran, execute one of the
1425 following commands:</p>
1427 <p><tt>% ./hello</tt></p>
1431 <p><tt>% lli hello.bc</tt></p></li>
1433 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1436 <p><tt>% llvm-dis < hello.bc | less</tt><p></li>
1438 <li><p>Compile the program to native assembly using the LLC code
1441 <p><tt>% llc hello.bc -o hello.s</tt></p>
1443 <li><p>Assemble the native assembly language file into a program:</p>
1445 <p><b>Solaris:</b><tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native</tt></p>
1446 <p><b>Others:</b><tt>% gcc hello.s -o hello.native</tt></p>
1448 <li><p>Execute the native code program:</p>
1450 <p><tt>% ./hello.native</tt></p></li>
1456 <!-- *********************************************************************** -->
1457 <div class="doc_section">
1458 <a name="problems">Common Problems</a>
1460 <!-- *********************************************************************** -->
1462 <div class="doc_text">
1464 <p>If you are having problems building or using LLVM, or if you have any other
1465 general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1466 Asked Questions</a> page.</p>
1470 <!-- *********************************************************************** -->
1471 <div class="doc_section">
1472 <a name="links">Links</a>
1474 <!-- *********************************************************************** -->
1476 <div class="doc_text">
1478 <p>This document is just an <b>introduction</b> to how to use LLVM to do
1479 some simple things... there are many more interesting and complicated things
1480 that you can do that aren't documented here (but we'll gladly accept a patch
1481 if you want to write something up!). For more information about LLVM, check
1485 <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
1486 <li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
1487 <li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project
1488 that Uses LLVM</a></li>
1493 <!-- *********************************************************************** -->
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1502 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1503 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1504 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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