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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++ front end 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>
275 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
280 <td>Linux<sup><a href="#pf_7">7</a></sup></td>
281 <td>Itanium (IA-64)</td>
285 <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
286 <td>Itanium (IA-64)</td>
293 <div class="doc_notes">
295 <li><a name="pf_1">Code generation supported for Pentium processors and
297 <li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
298 <li><a name="pf_3">No native code generation</a></li>
299 <li><a name="pf_4">Build is not complete: one or more tools don't link</a></li>
300 <li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
301 <li><a name="pf_6">The port is done using the MSYS shell.
302 <a href="http://www.mingw.org/MinGWiki/">Download</a> and install
303 bison (excl. M4.exe) and flex in that order. Build binutils-2.15 from source,
305 <li><a name="pf_7">Native code generation exists but is not complete.</a></li>
309 <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
310 mode, depending on the system (because of all the debug info), and the libraries
311 appear in more than one of the tools that get linked, so there is some
312 duplication. If you do not need many of the tools and you are space-conscious,
313 you can disable them individually in <tt>llvm/tools/Makefile</tt>. The Release
314 build requires considerably less space.</p>
316 <p>The LLVM suite <i>may</i> compile on other platforms, but it is not
317 guaranteed to do so. If compilation is successful, the LLVM utilities should be
318 able to assemble, disassemble, analyze, and optimize LLVM bytecode. Code
319 generation should work as well, although the generated native code may not work
320 on your platform.</p>
322 <p>The GCC front end is not very portable at the moment. If you want to get it
323 to work on another platform, you can download a copy of the source and <a
324 href="CFEBuildInstrs.html">try to compile it</a> on your platform.</p>
328 <!-- ======================================================================= -->
329 <div class="doc_subsection"><a name="software"><b>Software</b></a></div>
330 <div class="doc_text">
331 <p>Compiling LLVM requires that you have several software packages
332 installed. The table below lists those required packages. The Package column
333 is the usual name for the software package that LLVM depends on. The Version
334 column provides "known to work" versions of the package. The Notes column
335 describes how LLVM uses the package and provides other details.</p>
337 <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
340 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
341 <td>3.79, 3.79.1</td>
342 <td>Makefile/build processor</td>
346 <td><a href="http://gcc.gnu.org">GCC</a></td>
348 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
352 <td><a href="http://www.gnu.org/software/flex">Flex</a></td>
354 <td>LEX compiler</td>
358 <td><a href="http://www.gnu.org/software/bison/bison.html">Bison</a></td>
360 <td>YACC compiler</td>
364 <td><a href="https://www.cvshome.org/downloads.html">CVS</a></td>
366 <td>CVS access to LLVM<sup><a href="#sf2">2</a></sup></td>
370 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
372 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
376 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
378 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
382 <td><a href="http://expect.nist.gov/">expect</a></td>
384 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
388 <td><a href="http://www.perl.com/download.csp">perl</a></td>
390 <td>Nightly tester, utilities</td>
394 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
396 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
400 <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
402 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
406 <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
408 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
412 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
414 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
420 <div class="doc_notes">
422 <li><a name="sf3">Only the C and C++ languages are needed so there's no
423 need to build the other languages for LLVM's purposes.</a> See
424 <a href="#brokengcc">below</a> for specific version info.</li>
425 <li><a name="sf2">You only need CVS if you intend to build from the
426 latest LLVM sources. If you're working from a release distribution, you
427 don't need CVS.</a></li>
428 <li><a name="sf3">Only needed if you want to run the automated test
429 suite in the <tt>llvm/test</tt> directory.</a></li>
430 <li><a name="sf4">If you want to make changes to the configure scripts,
431 you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
432 or higher). You will also need automake (1.9.2). We only use aclocal
433 from that package.</a></li>
437 <p>Additionally, your compilation host is expected to have the usual
438 plethora of Unix utilities. Specifically:</p>
440 <li><b>ar</b> - archive library builder</li>
441 <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
442 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
443 <li><b>chmod</b> - change permissions on a file</li>
444 <li><b>cat</b> - output concatenation utility</li>
445 <li><b>cp</b> - copy files</li>
446 <li><b>date</b> - print the current date/time </li>
447 <li><b>echo</b> - print to standard output</li>
448 <li><b>egrep</b> - extended regular expression search utility</li>
449 <li><b>etags</b> - C/C++ tag file creator for vim/emacs</li>
450 <li><b>find</b> - find files/dirs in a file system</li>
451 <li><b>grep</b> - regular expression search utility</li>
452 <li><b>gzip*</b> - gzip command for distribution generation</li>
453 <li><b>gunzip*</b> - gunzip command for distribution checking</li>
454 <li><b>install</b> - install directories/files </li>
455 <li><b>mkdir</b> - create a directory</li>
456 <li><b>mv</b> - move (rename) files</li>
457 <li><b>ranlib</b> - symbol table builder for archive libraries</li>
458 <li><b>rm</b> - remove (delete) files and directories</li>
459 <li><b>sed</b> - stream editor for transforming output</li>
460 <li><b>sh</b> - Bourne shell for make build scripts</li>
461 <li><b>tar</b> - tape archive for distribution generation</li>
462 <li><b>test</b> - test things in file system</li>
463 <li><b>unzip*</b> - unzip command for distribution checking</li>
464 <li><b>zip*</b> - zip command for distribution generation</li>
468 <!-- ======================================================================= -->
469 <div class="doc_subsection">
470 <a name="brokengcc">Broken versions of GCC</a>
473 <div class="doc_text">
475 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
476 bugs in the compiler. In particular, several versions of GCC crash when trying
477 to compile LLVM. We routinely use GCC 3.3.3 and GCC 3.4.0 and have had success
478 with them (however, see below). Other versions of GCC will probably
479 work as well. GCC versions listed
480 here are known to not work. If you are using one of these versions, please try
481 to upgrade your GCC to something more recent. If you run into a problem with a
482 version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
483 us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
484 of GCC you are using.
487 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
488 problems in the STL that effectively prevent it from compiling LLVM.
491 <p><b>GCC 3.2.2</b>: This version of GCC fails to compile LLVM.</p>
493 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
494 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
495 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
497 <p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with
498 Cygwin does not work. Please <a href="CFEBuildInstrs.html#cygwin">upgrade
499 to a newer version</a> if possible.</p>
500 <p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
501 possibly others) does not compile LLVM correctly (it appears that exception
502 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
503 to a newer version of GCC.</p>
508 <!-- *********************************************************************** -->
509 <div class="doc_section">
510 <a name="starting"><b>Getting Started with LLVM</b></a>
512 <!-- *********************************************************************** -->
514 <div class="doc_text">
516 <p>The remainder of this guide is meant to get you up and running with
517 LLVM and to give you some basic information about the LLVM environment.</p>
519 <p>The later sections of this guide describe the <a
520 href="#layout">general layout</a> of the the LLVM source tree, a <a
521 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
522 href="#links">links</a> to find more information about LLVM or to get
526 <!-- ======================================================================= -->
527 <div class="doc_subsection">
528 <a name="terminology">Terminology and Notation</a>
531 <div class="doc_text">
533 <p>Throughout this manual, the following names are used to denote paths
534 specific to the local system and working environment. <i>These are not
535 environment variables you need to set but just strings used in the rest
536 of this document below</i>. In any of the examples below, simply replace
537 each of these names with the appropriate pathname on your local system.
538 All these paths are absolute:</p>
543 This is the top level directory of the LLVM source tree.
548 This is the top level directory of the LLVM object tree (i.e. the
549 tree where object files and compiled programs will be placed. It
550 can be the same as SRC_ROOT).
555 This is where the LLVM GCC Front End is installed.
557 For the pre-built GCC front end binaries, the LLVMGCCDIR is
558 <tt>cfrontend/<i>platform</i>/llvm-gcc</tt>.
563 <!-- ======================================================================= -->
564 <div class="doc_subsection">
565 <a name="environment">Setting Up Your Environment</a>
568 <div class="doc_text">
571 In order to compile and use LLVM, you may need to set some environment
575 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bytecode/libs</tt></dt>
576 <dd>[Optional] This environment variable helps LLVM linking tools find the
577 locations of your bytecode libraries. It is provided only a
578 convenience since you can specify the paths using the -L options of the
579 tools and the C/C++ front-end will use the bytecode files installed in its
580 <tt>lib</tt> directory.</dd>
585 <!-- ======================================================================= -->
586 <div class="doc_subsection">
587 <a name="unpack">Unpacking the LLVM Archives</a>
590 <div class="doc_text">
593 If you have the LLVM distribution, you will need to unpack it before you
594 can begin to compile it. LLVM is distributed as a set of two files: the LLVM
595 suite and the LLVM GCC front end compiled for your platform. There is an
596 additional test suite that is optional. Each file is a TAR archive that is
597 compressed with the gzip program.
600 <p>The files are as follows, with <em>x.y</em> marking the version number:
602 <dt><tt>llvm-x.y.tar.gz</tt></dt>
603 <dd>Source release for the LLVM libraries and tools.<br/></dd>
605 <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
606 <dd>Source release for the LLVM test suite.</dd>
608 <dt><tt>cfrontend-x.y.source.tar.gz</tt></dt>
609 <dd>Source release of the GCC front end.<br/></dd>
611 <dt><tt>cfrontend-x.y.sparc-sun-solaris2.8.tar.gz</tt></dt>
612 <dd>Binary release of the GCC front end for Solaris/Sparc.
615 <dt><tt>cfrontend-x.y.i686-redhat-linux-gnu.tar.gz</tt></dt>
616 <dd>Binary release of the GCC front end for Linux/x86.<br/></dd>
618 <dt><tt>cfrontend-x.y.i386-unknown-freebsd5.1.tar.gz</tt></dt>
619 <dd>Binary release of the GCC front end for FreeBSD/x86.<br/></dd>
621 <dt><tt>cfrontend-x.y.powerpc-apple-darwin7.6.0.tar.gz</tt></dt>
622 <dd>Binary release of the GCC front end for MacOS X/PPC.<br/></dd>
627 <!-- ======================================================================= -->
628 <div class="doc_subsection">
629 <a name="checkout">Checkout LLVM from CVS</a>
632 <div class="doc_text">
634 <p>If you have access to our CVS repository, you can get a fresh copy of
635 the entire source code. All you need to do is check it out from CVS as
639 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
640 <li><tt>cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login</tt>
641 <li>Hit the return key when prompted for the password.
642 <li><tt>cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co
646 <p>This will create an '<tt>llvm</tt>' directory in the current
647 directory and fully populate it with the LLVM source code, Makefiles,
648 test directories, and local copies of documentation files.</p>
650 <p>If you want to get a specific release (as opposed to the most recent
651 revision), you can specify a label. The following releases have the following
655 <li>Release 1.5: <b>RELEASE_15</b></li>
656 <li>Release 1.4: <b>RELEASE_14</b></li>
657 <li>Release 1.3: <b>RELEASE_13</b></li>
658 <li>Release 1.2: <b>RELEASE_12</b></li>
659 <li>Release 1.1: <b>RELEASE_11</b></li>
660 <li>Release 1.0: <b>RELEASE_1</b></li>
663 <p>If you would like to get the LLVM test suite (a separate package as of 1.4),
664 you get it from the CVS repository:</p>
667 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-test
669 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
670 configured by the LLVM configure script as well as automatically updated when
671 you run <tt>cvs update</tt>.</p>
673 <p>If you would like to get the GCC front end source code, you can also get it
674 from the CVS repository:</p>
677 cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-gcc
680 <p>Please note that you must follow <a href="CFEBuildInstrs.html">these
681 instructions</a> to successfully build the LLVM GCC front-end.</p>
685 <!-- ======================================================================= -->
686 <div class="doc_subsubsection">
687 <a name="mirrors">LLVM CVS Mirrors</a>
690 <div class="doc_text">
692 <p>If the main CVS server is overloaded or inaccessible, you can try one of
693 these user-hosted mirrors:</p>
696 <li><a href="http://llvm.x10sys.com/">Mirror hosted by eXtensible Systems
701 <!-- ======================================================================= -->
702 <div class="doc_subsection">
703 <a name="installcf">Install the GCC Front End</a>
706 <div class="doc_text">
708 <p>Before configuring and compiling the LLVM suite, you need to extract the LLVM
709 GCC front end from the binary distribution. It is used for building the
710 bytecode libraries later used by the GCC front end for linking programs, and its
711 location must be specified when the LLVM suite is configured.</p>
713 <p>To install the GCC front end, do the following:</p>
716 <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
717 <li><tt>gunzip --stdout cfrontend-<i>version</i>.<i>platform</i>.tar.gz | tar -xvf
721 <p>Next, you will need to fix your system header files:</p>
723 <p><tt>cd cfrontend/<i>platform</i><br>
724 ./fixheaders</tt></p>
726 <p>The binary versions of the GCC front end may not suit all of your needs. For
727 example, the binary distribution may include an old version of a system header
728 file, not "fix" a header file that needs to be fixed for GCC, or it may be
729 linked with libraries not available on your system.</p>
731 <p>In cases like these, you may want to try <a
732 href="CFEBuildInstrs.html">building the GCC front end from source.</a> This is
733 not for the faint of heart, so be forewarned.</p>
737 <!-- ======================================================================= -->
738 <div class="doc_subsection">
739 <a name="config">Local LLVM Configuration</a>
742 <div class="doc_text">
744 <p>Once checked out from the CVS repository, the LLVM suite source code must be
745 configured via the <tt>configure</tt> script. This script sets variables in the
746 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
747 <tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
748 the Makefiles needed to begin building LLVM.</p>
750 <p>The following environment variables are used by the <tt>configure</tt>
751 script to configure the build system:</p>
754 <tr><th>Variable</th><th>Purpose</th></tr>
757 <td>Tells <tt>configure</tt> which C compiler to use. By default,
758 <tt>configure</tt> will look for the first GCC C compiler in
759 <tt>PATH</tt>. Use this variable to override
760 <tt>configure</tt>'s default behavior.</td>
764 <td>Tells <tt>configure</tt> which C++ compiler to use. By default,
765 <tt>configure</tt> will look for the first GCC C++ compiler in
766 <tt>PATH</tt>. Use this variable to override
767 <tt>configure</tt>'s default behavior.</td>
771 <p>The following options can be used to set or enable LLVM specific options:</p>
774 <dt><i>--with-llvmgccdir</i></dt>
775 <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
776 The value of this option should specify the full pathname of the C/C++ Front
777 End to be used. If this option is not provided, the PATH will be searched for
778 a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
779 be inferred from the path found. If the option is not given, and no llvm-gcc
780 can be found in the path then a warning will be produced by
781 <tt>configure</tt> indicating this situation. LLVM may still be built with
782 the <tt>tools-only</tt> target but attempting to build the runtime libraries
783 will fail as these libraries require llvm-gcc and llvm-g++. See
784 <a href="#installcf">Install the GCC Front End</a> for details on installing
785 the C/C++ Front End. See
786 <a href="CFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
787 for details on building the C/C++ Front End.</dd>
788 <dt><i>--with-tclinclude</i></dt>
789 <dd>Path to the tcl include directory under which the <tt>tclsh</tt> can be
790 found. Use this if you have multiple tcl installations on your machine and you
791 want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
792 dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
793 option, the LLVM configure script will search for tcl 8.4 and 8.3 releases.
796 <dt><i>--enable-optimized</i></dt>
798 Enables optimized compilation by default (debugging symbols are removed
799 and GCC optimization flags are enabled). The default is to use an
800 unoptimized build (also known as a debug build).
803 <dt><i>--enable-jit</i></dt>
805 Compile the Just In Time (JIT) compiler functionality. This is not
807 on all platforms. The default is dependent on platform, so it is best
808 to explicitly enable it if you want it.
811 <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
812 <dd>Controls which targets will be built and linked into llc. The default
813 value for <tt>target_options</tt> is "all" which builds and links all
814 available targets. The value "host-only" can be specified to build only a
815 native compiler (no cross-compiler targets available). The "native" target is
816 selected as the target of the build host. You can also specify a comma
817 separated list of target names that you want available in llc. The target
818 names use all lower case. The current set is of targets is: <br/>
819 <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
821 <dt><i>--enable-doxygen</i></dt>
822 <dd>Look for the doxygen program and enable construction of doxygen based
823 documentation from the source code. This is disabled by default because
824 generating the documentation can take a long time and producess 100s of
825 megabytes of output.</dd>
828 <p>To configure LLVM, follow these steps:</p>
831 <li>Change directory into the object root directory:
833 <tt>cd <i>OBJ_ROOT</i></tt>
836 <li>Run the <tt>configure</tt> script located in the LLVM source tree:
838 <tt><i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</tt>
844 <!-- ======================================================================= -->
845 <div class="doc_subsection">
846 <a name="compile">Compiling the LLVM Suite Source Code</a>
849 <div class="doc_text">
851 <p>Once you have configured LLVM, you can build it. There are three types of
857 These builds are the default when one types <tt>gmake</tt> (unless the
858 <tt>--enable-optimized</tt> option was used during configuration). The
859 build system will compile the tools and libraries with debugging
863 <dt>Release (Optimized) Builds
865 These builds are enabled with the <tt>--enable-optimized</tt> option to
866 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
867 <tt>gmake</tt> command line. For these builds, the build system will
868 compile the tools and libraries with GCC optimizations enabled and strip
869 debugging information from the libraries and executables it generates.
874 These builds are for use with profiling. They compile profiling
875 information into the code for use with programs like <tt>gprof</tt>.
876 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
877 on the <tt>gmake</tt> command line.
880 <p>Once you have LLVM configured, you can build it by entering the
881 <i>OBJ_ROOT</i> directory and issuing the following command:</p>
883 <p><tt>gmake</tt></p>
885 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
886 are using a version of GCC that is known not to compile LLVM.</p>
889 If you have multiple processors in your machine, you may wish to use some of
890 the parallel build options provided by GNU Make. For example, you could use the
893 <p><tt>gmake -j2</tt></p>
895 <p>There are several special targets which are useful when working with the LLVM
899 <dt><tt>gmake clean</tt>
901 Removes all files generated by the build. This includes object files,
902 generated C/C++ files, libraries, and executables.
905 <dt><tt>gmake dist-clean</tt>
907 Removes everything that <tt>gmake clean</tt> does, but also removes files
908 generated by <tt>configure</tt>. It attempts to return the source tree to the
909 original state in which it was shipped.
912 <dt><tt>gmake install</tt>
914 Installs LLVM header files, libraries, tools, and documentation in a
916 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
917 defaults to <tt>/usr/local</tt>.
920 <dt><tt>gmake -C runtime install-bytecode</tt>
922 Assuming you built LLVM into $OBJDIR, when this command is run, it will
923 install bytecode libraries into the GCC front end's bytecode library
924 directory. If you need to update your bytecode libraries,
925 this is the target to use once you've built them.
929 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
930 details on these <tt>make</tt> targets and descriptions of other targets
933 <p>It is also possible to override default values from <tt>configure</tt> by
934 declaring variables on the command line. The following are some examples:</p>
937 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
939 Perform a Release (Optimized) build.
942 <dt><tt>gmake ENABLE_PROFILING=1</tt>
944 Perform a Profiling build.
947 <dt><tt>gmake VERBOSE=1</tt>
949 Print what <tt>gmake</tt> is doing on standard output.
952 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
953 <dd>Ask each tool invoked by the makefiles to print out what it is doing on
954 the standard output. This also implies <tt>VERBOSE=1</tt>.
958 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
959 it and any subdirectories that it contains. Entering any directory inside the
960 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
961 that directory that is out of date.</p>
965 <!-- ======================================================================= -->
966 <div class="doc_subsection">
967 <a name="objfiles">The Location of LLVM Object Files</a>
970 <div class="doc_text">
972 <p>The LLVM build system is capable of sharing a single LLVM source tree among
973 several LLVM builds. Hence, it is possible to build LLVM for several different
974 platforms or configurations using the same source tree.</p>
976 <p>This is accomplished in the typical autoconf manner:</p>
979 <li><p>Change directory to where the LLVM object files should live:</p>
981 <p><tt>cd <i>OBJ_ROOT</i></tt></p></li>
983 <li><p>Run the <tt>configure</tt> script found in the LLVM source
986 <p><tt><i>SRC_ROOT</i>/configure</tt></p></li>
989 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
990 named after the build type:</p>
997 <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
999 <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1007 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1009 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1017 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1019 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1025 <!-- ======================================================================= -->
1026 <div class="doc_subsection">
1027 <a name="optionalconfig">Optional Configuration Items</a>
1030 <div class="doc_text">
1033 If you're running on a Linux system that supports the "<a
1034 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">
1036 module, and you have root access on the system, you can set your system up to
1037 execute LLVM bytecode files directly. To do this, use commands like this (the
1038 first command may not be required if you are already using the module):</p>
1040 <div class="doc_code">
1042 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1043 $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
1044 $ chmod u+x hello.bc (if needed)
1050 This allows you to execute LLVM bytecode files directly. Thanks to Jack
1051 Cummings for pointing this out!
1057 <!-- *********************************************************************** -->
1058 <div class="doc_section">
1059 <a name="layout"><b>Program Layout</b></a>
1061 <!-- *********************************************************************** -->
1063 <div class="doc_text">
1065 <p>One useful source of information about the LLVM source base is the LLVM <a
1066 href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1067 href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>.
1068 The following is a brief introduction to code layout:</p>
1072 <!-- ======================================================================= -->
1073 <div class="doc_subsection"><a name="cvsdir"><tt>CVS</tt> directories</a></div>
1074 <div class="doc_text">
1075 <p>Every directory checked out of CVS will contain a <tt>CVS</tt> directory; for
1076 the most part these can just be ignored.</p>
1079 <!-- ======================================================================= -->
1080 <div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1081 <div class="doc_text">
1082 <p>This directory contains some simple examples of how to use the LLVM IR and
1086 <!-- ======================================================================= -->
1087 <div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1088 <div class="doc_text">
1090 <p>This directory contains public header files exported from the LLVM
1091 library. The three main subdirectories of this directory are:</p>
1094 <dt><tt><b>llvm/include/llvm</b></tt></dt>
1095 <dd>This directory contains all of the LLVM specific header files. This
1096 directory also has subdirectories for different portions of LLVM:
1097 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1100 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1101 <dd>This directory contains generic support libraries that are provided with
1102 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1103 and a Command Line option processing library store their header files here.
1106 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1107 <dd>This directory contains header files configured by the <tt>configure</tt>
1108 script. They wrap "standard" UNIX and C header files. Source code can
1109 include these header files which automatically take care of the conditional
1110 #includes that the <tt>configure</tt> script generates.</dd>
1114 <!-- ======================================================================= -->
1115 <div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1116 <div class="doc_text">
1118 <p>This directory contains most of the source files of the LLVM system. In LLVM,
1119 almost all code exists in libraries, making it very easy to share code among the
1120 different <a href="#tools">tools</a>.</p>
1123 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1124 <dd> This directory holds the core LLVM source files that implement core
1125 classes like Instruction and BasicBlock.</dd>
1127 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1128 <dd>This directory holds the source code for the LLVM assembly language parser
1131 <dt><tt><b>llvm/lib/ByteCode/</b></tt></dt>
1132 <dd>This directory holds code for reading and write LLVM bytecode.</dd>
1134 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1135 different program analyses, such as Dominator Information, Call Graphs,
1136 Induction Variables, Interval Identification, Natural Loop Identification,
1139 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1140 <dd> This directory contains the source code for the LLVM to LLVM program
1141 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1142 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1143 Elimination, and many others.</dd>
1145 <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1146 <dd> This directory contains files that describe various target architectures
1147 for code generation. For example, the <tt>llvm/lib/Target/SparcV9</tt>
1148 directory holds the Sparc machine description while
1149 <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter</dd>
1151 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1152 <dd> This directory contains the major parts of the code generator: Instruction
1153 Selector, Instruction Scheduling, and Register Allocation.</dd>
1155 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1156 <dd> This directory contains the source level debugger library that makes
1157 it possible to instrument LLVM programs so that a debugger could identify
1158 source code locations at which the program is executing.</dd>
1160 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1161 <dd> This directory contains libraries for executing LLVM bytecode directly
1162 at runtime in both interpreted and JIT compiled fashions.</dd>
1164 <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1165 <dd> This directory contains the source code that corresponds to the header
1166 files located in <tt>llvm/include/Support/</tt>.</dd>
1168 <dt><tt><b>llvm/lib/System/</b></tt></dt>
1169 <dd>This directory contains the operating system abstraction layer that
1170 shields LLVM from platform-specific coding.</dd>
1175 <!-- ======================================================================= -->
1176 <div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1177 <div class="doc_text">
1178 <p>This directory contains projects that are not strictly part of LLVM but are
1179 shipped with LLVM. This is also the directory where you should create your own
1180 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1181 to set up your own project. See <tt>llvm/projects/Stacker</tt> for a fully
1182 functional example of a compiler front end.</p>
1185 <!-- ======================================================================= -->
1186 <div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1187 <div class="doc_text">
1189 <p>This directory contains libraries which are compiled into LLVM bytecode and
1190 used when linking programs with the GCC front end. Most of these libraries are
1191 skeleton versions of real libraries; for example, libc is a stripped down
1192 version of glibc.</p>
1194 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1199 <!-- ======================================================================= -->
1200 <div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1201 <div class="doc_text">
1202 <p>This directory contains feature and regression tests and other basic sanity
1203 checks on the LLVM infrastructure. These are intended to run quickly and cover
1204 a lot of territory without being exhaustive.</p>
1207 <!-- ======================================================================= -->
1208 <div class="doc_subsection"><a name="llvmtest"><tt>llvm-test</tt></a></div>
1209 <div class="doc_text">
1210 <p>This is not a directory in the normal llvm module; it is a separate CVS
1211 module that must be checked out (usually to <tt>projects/llvm-test</tt>). This
1212 module contains a comprehensive correctness, performance, and benchmarking
1214 suite for LLVM. It is a separate CVS module because not every LLVM user is
1215 interested in downloading or building such a comprehensive test suite. For
1216 further details on this test suite, please see the
1217 <a href="TestingGuide.html">Testing Guide</a> document.</p>
1220 <!-- ======================================================================= -->
1221 <div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1222 <div class="doc_text">
1224 <p>The <b>tools</b> directory contains the executables built out of the
1225 libraries above, which form the main part of the user interface. You can
1226 always get help for a tool by typing <tt>tool_name --help</tt>. The
1227 following is a brief introduction to the most important tools. More detailed
1228 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1231 <dt><tt><b>analyze</b></tt></dt>
1232 <dd><tt>analyze</tt> is used to run a specific
1233 analysis on an input LLVM bytecode file and print out the results. It is
1234 primarily useful for debugging analyses, or familiarizing yourself with
1235 what an analysis does.</dd>
1237 <dt><tt><b>bugpoint</b></tt></dt>
1238 <dd><tt>bugpoint</tt> is used to debug
1239 optimization passes or code generation backends by narrowing down the
1240 given test case to the minimum number of passes and/or instructions that
1241 still cause a problem, whether it is a crash or miscompilation. See <a
1242 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1243 on using <tt>bugpoint</tt>.</dd>
1245 <dt><tt><b>llvmc</b></tt></dt>
1246 <dd>The LLVM Compiler Driver. This program can
1247 be configured to utilize both LLVM and non-LLVM compilation tools to enable
1248 pre-processing, translation, optimization, assembly, and linking of programs
1249 all from one command line. <tt>llvmc</tt> also takes care of processing the
1250 dependent libraries found in bytecode. This reduces the need to get the
1251 traditional <tt>-l<name></tt> options right on the command line. Please
1252 note that this tool is new in 1.4 and considered experimental. It will be
1253 fully supported in 1.5.</dd>
1255 <dt><tt><b>llvm-ar</b></tt></dt>
1256 <dd>The archiver produces an archive containing
1257 the given LLVM bytecode files, optionally with an index for faster
1260 <dt><tt><b>llvm-as</b></tt></dt>
1261 <dd>The assembler transforms the human readable LLVM assembly to LLVM
1264 <dt><tt><b>llvm-dis</b></tt></dt>
1265 <dd>The disassembler transforms the LLVM bytecode to human readable
1268 <dt><tt><b>llvm-ld</b></tt></dt>
1269 <dd><tt>llvm-ld</tt> is very similar to gccld and provides a general purpose
1270 and extensible linker for LLVM. This is the linker invoked by <tt>llvmc</tt>.
1271 It allows optimization modules to be loaded so that language specific
1272 optimizations can be applied at link time. Please note that this tool is new
1273 in LLVM 1.4 and still considered experimental. It will be fully supported in
1276 <dt><tt><b>llvm-link</b></tt></dt>
1277 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1278 a single program.</dd>
1280 <dt><tt><b>lli</b></tt></dt>
1281 <dd><tt>lli</tt> is the LLVM interpreter, which
1282 can directly execute LLVM bytecode (although very slowly...). In addition
1283 to a simple interpreter, <tt>lli</tt> also has a tracing mode (entered by
1284 specifying <tt>-trace</tt> on the command line). Finally, for
1285 architectures that support it (currently x86, Sparc, and PowerPC), by default,
1286 <tt>lli</tt> will function as a Just-In-Time compiler (if the
1287 functionality was compiled in), and will execute the code <i>much</i>
1288 faster than the interpreter.</dd>
1290 <dt><tt><b>llc</b></tt></dt>
1291 <dd> <tt>llc</tt> is the LLVM backend compiler, which
1292 translates LLVM bytecode to a SPARC or x86 assembly file, or to C code (with
1293 the -march=c option).</dd>
1295 <dt><tt><b>llvm-gcc</b></tt></dt>
1296 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend
1297 that has been retargeted to emit LLVM code as the machine code output. It
1298 works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
1299 -o</tt> options that are typically used. The source code for the
1300 <tt>llvm-gcc</tt> tool is currently not included in the LLVM CVS tree
1301 because it is quite large and not very interesting.
1304 <dt><tt><b>gccas</b></tt></dt>
1305 <dd>This tool is invoked by the <tt>llvm-gcc</tt> frontend as the
1306 "assembler" part of the compiler. This tool actually assembles LLVM
1307 assembly to LLVM bytecode, performs a variety of optimizations, and
1308 outputs LLVM bytecode. Thus when you invoke
1309 <tt>llvm-gcc -c x.c -o x.o</tt>, you are causing <tt>gccas</tt> to be
1310 run, which writes the <tt>x.o</tt> file (which is an LLVM bytecode file
1311 that can be disassembled or manipulated just like any other bytecode
1312 file). The command line interface to <tt>gccas</tt> is designed to be
1313 as close as possible to the <b>system</b> `<tt>as</tt>' utility so that
1314 the gcc frontend itself did not have to be modified to interface to
1315 a "weird" assembler.</dd>
1317 <dt><tt><b>gccld</b></tt></dt>
1318 <dd><tt>gccld</tt> links together several LLVM bytecode files into one
1319 bytecode file and does some optimization. It is the linker invoked by
1320 the GCC frontend when multiple .o files need to be linked together.
1321 Like <tt>gccas</tt>, the command line interface of <tt>gccld</tt> is
1322 designed to match the system linker, to aid interfacing with the GCC
1328 <dt><tt><b>opt</b></tt></dt>
1329 <dd><tt>opt</tt> reads LLVM bytecode, applies a
1330 series of LLVM to LLVM transformations (which are specified on the command
1331 line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
1332 command is a good way to get a list of the program transformations
1333 available in LLVM.</dd>
1337 <!-- ======================================================================= -->
1338 <div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1339 <div class="doc_text">
1341 <p>This directory contains utilities for working with LLVM source code, and some
1342 of the utilities are actually required as part of the build process because they
1343 are code generators for parts of LLVM infrastructure.</p>
1346 <dt><tt><b>Burg/</b></tt> <dd><tt>Burg</tt> is an instruction selector
1347 generator -- it builds trees on which it then performs pattern-matching to
1348 select instructions according to the patterns the user has specified. Burg
1349 is currently used in the Sparc V9 backend.<p>
1351 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1352 that finds differences between code that LLC generates and code that LLI
1353 generates. This is a useful tool if you are debugging one of them,
1354 assuming that the other generates correct output. For the full user
1355 manual, run <tt>`perldoc codegen-diff'</tt>.<p>
1357 <dt><tt><b>cvsupdate</b></tt> <dd><tt>cvsupdate</tt> is a script that will
1358 update your CVS tree, but produce a much cleaner and more organized output
1359 than simply running <tt>`cvs -z3 up -dP'</tt> will. For example, it will group
1360 together all the new and updated files and modified files in separate
1361 sections, so you can see at a glance what has changed. If you are at the
1362 top of your LLVM CVS tree, running <tt>utils/cvsupdate</tt> is the
1363 preferred way of updating the tree.<p>
1365 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1366 syntax-highlighting files which will work with Emacs and XEmacs editors,
1367 providing syntax highlighting support for LLVM assembly files and TableGen
1368 description files. For information on how to use the syntax files, consult
1369 the <tt>README</tt> file in that directory.<p>
1371 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1372 and outputs all non-generated source files, which is useful if one wishes
1373 to do a lot of development across directories and does not want to
1374 individually find each file. One way to use it is to run, for example:
1375 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1378 <dt><tt><b>llvmgrep</b></tt></dt>
1379 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1380 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1381 line. This is a very efficient way of searching the source base for a
1382 particular regular expression.</dd>
1384 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1385 files in the current directory and then compiles and links the tool that
1386 is the first argument. For example, assuming you are in the directory
1387 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1388 simply running <tt>makellvm llc</tt> will make a build of the current
1389 directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1390 causing a re-linking of LLC.<p>
1392 <dt><tt><b>NightlyTest.pl</b></tt> and
1393 <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1394 cron script to generate nightly status reports of the functionality of
1395 tools, and the results can be seen by following the appropriate link on
1396 the <a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a>.<p>
1398 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1399 the tool used to generate register descriptions, instruction set
1400 descriptions, and even assemblers from common TableGen description
1403 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1404 syntax-highlighting files which will work with the VIM editor, providing
1405 syntax highlighting support for LLVM assembly files and TableGen
1406 description files. For information on how to use the syntax files, consult
1407 the <tt>README</tt> file in that directory.<p>
1413 <!-- ======================================================================= -->
1414 <div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1415 <div class="doc_text">
1416 <p>This directory contains build scripts and project files for use with
1417 Visual C++. This allows developers on Windows to build LLVM without the need
1418 for Cygwin. The contents of this directory should be considered experimental
1422 <!-- *********************************************************************** -->
1423 <div class="doc_section">
1424 <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1426 <!-- *********************************************************************** -->
1428 <div class="doc_text">
1431 <li>First, create a simple C file, name it 'hello.c':
1433 #include <stdio.h>
1435 printf("hello world\n");
1440 <li><p>Next, compile the C file into a LLVM bytecode file:</p>
1441 <p><tt>% llvm-gcc hello.c -o hello</tt></p>
1443 <p>Note that you should have already built the tools and they have to be
1444 in your path, at least <tt>gccas</tt> and <tt>gccld</tt>.</p>
1446 <p>This will create two result files: <tt>hello</tt> and
1447 <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
1448 corresponds the the compiled program and the library facilities that it
1449 required. <tt>hello</tt> is a simple shell script that runs the bytecode
1450 file with <tt>lli</tt>, making the result directly executable. Note that
1451 all LLVM optimizations are enabled by default, so there is no need for a
1452 "-O3" switch.</p></li>
1454 <li><p>Run the program. To make sure the program ran, execute one of the
1455 following commands:</p>
1457 <p><tt>% ./hello</tt></p>
1461 <p><tt>% lli hello.bc</tt></p></li>
1463 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1466 <p><tt>% llvm-dis < hello.bc | less</tt><p></li>
1468 <li><p>Compile the program to native assembly using the LLC code
1471 <p><tt>% llc hello.bc -o hello.s</tt></p>
1473 <li><p>Assemble the native assembly language file into a program:</p>
1475 <p><b>Solaris:</b><tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native</tt></p>
1476 <p><b>Others:</b><tt>% gcc hello.s -o hello.native</tt></p>
1478 <li><p>Execute the native code program:</p>
1480 <p><tt>% ./hello.native</tt></p></li>
1486 <!-- *********************************************************************** -->
1487 <div class="doc_section">
1488 <a name="problems">Common Problems</a>
1490 <!-- *********************************************************************** -->
1492 <div class="doc_text">
1494 <p>If you are having problems building or using LLVM, or if you have any other
1495 general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1496 Asked Questions</a> page.</p>
1500 <!-- *********************************************************************** -->
1501 <div class="doc_section">
1502 <a name="links">Links</a>
1504 <!-- *********************************************************************** -->
1506 <div class="doc_text">
1508 <p>This document is just an <b>introduction</b> to how to use LLVM to do
1509 some simple things... there are many more interesting and complicated things
1510 that you can do that aren't documented here (but we'll gladly accept a patch
1511 if you want to write something up!). For more information about LLVM, check
1515 <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
1516 <li><a href="http://llvm.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
1517 <li><a href="http://llvm.cs.uiuc.edu/docs/Projects.html">Starting a Project
1518 that Uses LLVM</a></li>
1523 <!-- *********************************************************************** -->
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1532 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1533 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1534 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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