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  11 <div class="doc_title">
  12   Getting Started with the LLVM System
  13 </div>
  14
  15 <ul>
  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>
  19     <ol>
  20       <li><a href="#hardware">Hardware</a></li>
  21       <li><a href="#software">Software</a></li>
  22       <li><a href="#brokengcc">Broken versions of GCC and other tools</a></li>
  23     </ol></li>
  24
  25   <li><a href="#starting">Getting Started with LLVM</a>
  26     <ol>
  27       <li><a href="#terminology">Terminology and Notation</a></li>
  28       <li><a href="#environment">Setting Up Your Environment</a></li>
  29       <li><a href="#unpack">Unpacking the LLVM Archives</a></li>
  30       <li><a href="#checkout">Checkout LLVM from Subversion</a></li>
  31       <li><a href="#installcf">Install the GCC Front End</a></li>
  32       <li><a href="#config">Local LLVM Configuration</a></li>
  33       <li><a href="#compile">Compiling the LLVM Suite Source Code</a></li>
  34       <li><a href="#cross-compile">Cross-Compiling LLVM</a></li>
  35       <li><a href="#objfiles">The Location of LLVM Object Files</a></li>
  36       <li><a href="#optionalconfig">Optional Configuration Items</a></li>
  37     </ol></li>
  38
  39   <li><a href="#layout">Program layout</a>
  40     <ol>
  41       <li><a href="#examples"><tt>llvm/examples</tt></a></li>
  42       <li><a href="#include"><tt>llvm/include</tt></a></li>
  43       <li><a href="#lib"><tt>llvm/lib</tt></a></li>
  44       <li><a href="#projects"><tt>llvm/projects</tt></a></li>
  45       <li><a href="#runtime"><tt>llvm/runtime</tt></a></li>
  46       <li><a href="#test"><tt>llvm/test</tt></a></li>
  47       <li><a href="#llvmtest"><tt>llvm-test</tt></a></li>
  48       <li><a href="#tools"><tt>llvm/tools</tt></a></li>
  49       <li><a href="#utils"><tt>llvm/utils</tt></a></li>
  50       <li><a href="#win32"><tt>llvm/win32</tt></a></li>
  51     </ol></li>
  52
  53   <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
  54       <ol>
  55          <li><a href="#tutorial4">Example with llvm-gcc4</a></li>
  56       </ol>
  57   <li><a href="#problems">Common Problems</a>
  58   <li><a href="#links">Links</a>
  59 </ul>
  60
  61 <div class="doc_author">
  62   <p>Written by:
  63     <a href="mailto:criswell@uiuc.edu">John Criswell</a>,
  64     <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
  65     <a href="http://misha.brukman.net">Misha Brukman</a>,
  66     <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and
  67     <a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>.
  68   </p>
  69 </div>
  70
  71
  72 <!-- *********************************************************************** -->
  73 <div class="doc_section">
  74   <a name="overview"><b>Overview</b></a>
  75 </div>
  76 <!-- *********************************************************************** -->
  77
  78 <div class="doc_text">
  79
  80 <p>Welcome to LLVM! In order to get started, you first need to know some
  81 basic information.</p>
  82
  83 <p>First, LLVM comes in two pieces. The first piece is the LLVM suite. This
  84 contains all of the tools, libraries, and header files needed to use the low
  85 level virtual machine.  It contains an assembler, disassembler, bitcode
  86 analyzer and bitcode optimizer.  It also contains a test suite that can be
  87 used to test the LLVM tools and the GCC front end.</p>
  88
  89 <p>The second piece is the GCC front end.  This component provides a version of
  90 GCC that compiles C and C++ code into LLVM bitcode.  Currently, the GCC front
  91 end uses the GCC parser to convert code to LLVM.  Once
  92 compiled into LLVM bitcode, a program can be manipulated with the LLVM tools
  93 from the LLVM suite.</p>
  94
  95 <p>
  96 There is a third, optional piece called llvm-test.  It is a suite of programs
  97 with a testing harness that can be used to further test LLVM's functionality
  98 and performance.
  99 </p>
 100
 101 </div>
 102
 103 <!-- *********************************************************************** -->
 104 <div class="doc_section">
 105   <a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a>
 106 </div>
 107 <!-- *********************************************************************** -->
 108
 109 <div class="doc_text">
 110
 111 <p>Here's the short story for getting up and running quickly with LLVM:</p>
 112
 113 <ol>
 114   <li>Read the documentation.</li>
 115   <li>Read the documentation.</li>
 116   <li>Remember that you were warned twice about reading the documentation.</li>
 117   <li>Install the llvm-gcc-4.2 front end if you intend to compile C or C++:
 118     <ol>
 119       <li><tt>cd <i>where-you-want-the-C-front-end-to-live</i></tt></li>
 120       <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf -</tt>
 121       </li>
 122       <li>Note: If the binary extension is ".bz" use bunzip2 instead of gunzip.</li>
 123       <li>Add llvm-gcc's "bin" directory to your PATH variable.</li>
 124     </ol></li>
 125
 126   <li>Get the LLVM Source Code
 127   <ul>
 128     <li>With the distributed files (or use <a href="#checkout">SVN</a>):
 129     <ol>
 130       <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
 131       <li><tt>gunzip --stdout llvm-<i>version</i>.tar.gz | tar -xvf -</tt>
 132     </ol></li>
 133
 134   </ul></li>
 135
 136   <li><b>[Optional]</b> Get the Test Suite Source Code
 137   <ul>
 138     <li>With the distributed files (or use <a href="#checkout">SVN</a>):
 139     <ol>
 140       <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
 141       <li><tt>cd llvm/projects</tt>
 142       <li><tt>gunzip --stdout llvm-test-<i>version</i>.tar.gz | tar -xvf -</tt>
 143     </ol></li>
 144
 145   </ul></li>
 146
 147
 148   <li>Configure the LLVM Build Environment
 149   <ol>
 150     <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
 151     <li><tt><i>/path/to/llvm/</i>configure [options]</tt><br>
 152     Some common options:
 153
 154       <ul>
 155         <li><tt>--prefix=<i>directory</i></tt>
 156         <p>Specify for <i>directory</i> the full pathname of where you
 157         want the LLVM tools and libraries to be installed (default
 158         <tt>/usr/local</tt>).</p></li>
 159         <li><tt>--with-llvmgccdir=<i>directory</i></tt>
 160         <p>Optionally, specify for <i>directory</i> the full pathname of the
 161         C/C++ front end installation to use with this LLVM configuration. If
 162         not specified, the PATH will be searched.  This is only needed if you
 163         want to run the testsuite or do some special kinds of LLVM builds.</p></li>
 164         <li><tt>--enable-spec2000=<i>directory</i></tt>
 165             <p>Enable the SPEC2000 benchmarks for testing.  The SPEC2000
 166             benchmarks should be available in
 167             <tt><i>directory</i></tt>.</p></li>
 168       </ul>
 169   </ol></li>
 170
 171   <li>Build the LLVM Suite:
 172   <ol>
 173       <li><tt>gmake -k |&amp; tee gnumake.out
 174       &nbsp;&nbsp;&nbsp;# this is csh or tcsh syntax</tt></li>
 175       <li>If you get an "internal compiler error (ICE)" or test failures, see
 176           <a href="#brokengcc">below</a>.</li>
 177   </ol>
 178
 179 </ol>
 180
 181 <p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
 182 detailed information on configuring and compiling LLVM.  See <a
 183 href="#environment">Setting Up Your Environment</a> for tips that simplify
 184 working with the GCC front end and LLVM tools.  Go to <a href="#layout">Program
 185 Layout</a> to learn about the layout of the source code tree.</p>
 186
 187 </div>
 188
 189 <!-- *********************************************************************** -->
 190 <div class="doc_section">
 191   <a name="requirements"><b>Requirements</b></a>
 192 </div>
 193 <!-- *********************************************************************** -->
 194
 195 <div class="doc_text">
 196
 197 <p>Before you begin to use the LLVM system, review the requirements given below.
 198 This may save you some trouble by knowing ahead of time what hardware and
 199 software you will need.</p>
 200
 201 </div>
 202
 203 <!-- ======================================================================= -->
 204 <div class="doc_subsection">
 205   <a name="hardware"><b>Hardware</b></a>
 206 </div>
 207
 208 <div class="doc_text">
 209
 210 <p>LLVM is known to work on the following platforms:</p>
 211
 212 <table cellpadding="3" summary="Known LLVM platforms">
 213 <tr>
 214   <th>OS</th>
 215   <th>Arch</th>
 216   <th>Compilers</th>
 217 </tr>
 218 <tr>
 219   <td>AuroraUX</td>
 220   <td>x86<sup><a href="#pf_1">1</a></sup></td>
 221   <td>GCC</td>
 222 </tr>
 223 <tr>
 224   <td>Linux</td>
 225   <td>x86<sup><a href="#pf_1">1</a></sup></td>
 226   <td>GCC</td>
 227 </tr>
 228 <tr>
 229   <td>Linux</td>
 230   <td>amd64</td>
 231   <td>GCC</td>
 232 </tr>
 233 <tr>
 234   <td>Solaris</td>
 235   <td>V9 (Ultrasparc)</td>
 236   <td>GCC</td>
 237 </tr>
 238 <tr>
 239   <td>FreeBSD</td>
 240   <td>x86<sup><a href="#pf_1">1</a></sup></td>
 241   <td>GCC</td>
 242 </tr>
 243 <tr>
 244   <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
 245   <td>PowerPC</td>
 246   <td>GCC</td>
 247 </tr>
 248 <tr>
 249   <td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td>
 250   <td>x86</td>
 251   <td>GCC</td>
 252 </tr>
 253 <tr>
 254   <td>Cygwin/Win32</td>
 255   <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a></sup></td>
 256   <td>GCC 3.4.X, binutils 2.15</td>
 257 </tr>
 258 <tr>
 259   <td>MinGW/Win32</td>
 260   <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,
 261      <a href="#pf_8">8</a>, <a href="#pf_10">10</a></sup></td>
 262   <td>GCC 3.4.X, binutils 2.15</td>
 263 </tr>
 264 </table>
 265
 266 <p>LLVM has partial support for the following platforms:</p>
 267
 268 <table summary="LLVM partial platform support">
 269 <tr>
 270   <th>OS</th>
 271   <th>Arch</th>
 272   <th>Compilers</th>
 273 </tr>
 274 <tr>
 275   <td>Windows</td>
 276   <td>x86<sup><a href="#pf_1">1</a></sup></td>
 277   <td>Visual Studio 2005 SP1 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
 278 <tr>
 279   <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
 280   <td>PowerPC</td>
 281   <td>GCC</td>
 282 </tr>
 283 <tr>
 284   <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
 285   <td>PowerPC</td>
 286   <td>GCC</td>
 287 </tr>
 288
 289 <tr>
 290   <td>Linux<sup><a href="#pf_7">7</a></sup></td>
 291   <td>Alpha</td>
 292   <td>GCC</td>
 293 </tr>
 294 <tr>
 295   <td>Linux<sup><a href="#pf_7">7</a></sup></td>
 296   <td>Itanium (IA-64)</td>
 297   <td>GCC</td>
 298 </tr>
 299 <tr>
 300   <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
 301   <td>Itanium (IA-64)</td>
 302   <td>HP aCC</td>
 303 </tr>
 304 </table>
 305
 306 <p><b>Notes:</b></p>
 307
 308 <div class="doc_notes">
 309 <ol>
 310 <li><a name="pf_1">Code generation supported for Pentium processors and
 311 up</a></li>
 312 <li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
 313 <li><a name="pf_3">No native code generation</a></li>
 314 <li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li>
 315 <li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
 316 <li><a name="pf_6">The port is done using the MSYS shell.</a></li>
 317 <li><a name="pf_7">Native code generation exists but is not complete.</a></li>
 318 <li><a name="pf_8">Binutils</a> up to post-2.17 has bug in bfd/cofflink.c
 319     preventing LLVM from building correctly. Several workarounds have been
 320     introduced into LLVM build system, but the bug can occur anytime in the
 321     future. We highly recommend that you rebuild your current binutils with the
 322     patch from <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=2659">
 323     Binutils bugzilla</a>, if it wasn't already applied.</li>
 324 <li><a name="pf_9">XCode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip
 325     internal LLVM assert messages when compiled for Release at optimization
 326     levels greater than 0 (i.e., <i>"-O1"</i> and higher).
 327     Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
 328     if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
 329 <li><a name="pf_10">For MSYS/MinGW on Windows, be sure to install the MSYS
 330     version of the perl package, and be sure it appears in your path
 331     before any Windows-based versions such as Strawberry Perl and
 332     ActivePerl, as these have Windows-specifics that will cause the
 333     build to fail.</a></li>
 334 </ol>
 335 </div>
 336
 337 <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
 338 mode, depending on the system (it is so large because of all the debugging
 339 information and the fact that the libraries are statically linked into multiple
 340 tools).  If you do not need many of the tools and you are space-conscious, you
 341 can pass <tt>ONLY_TOOLS="tools you need"</tt> to make.  The Release build
 342 requires considerably less space.</p>
 343
 344 <p>The LLVM suite <i>may</i> compile on other platforms, but it is not
 345 guaranteed to do so.  If compilation is successful, the LLVM utilities should be
 346 able to assemble, disassemble, analyze, and optimize LLVM bitcode.  Code
 347 generation should work as well, although the generated native code may not work
 348 on your platform.</p>
 349
 350 <p>The GCC front end is not very portable at the moment.  If you want to get it
 351 to work on another platform, you can download a copy of the source and <a
 352 href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
 353
 354 </div>
 355
 356 <!-- ======================================================================= -->
 357 <div class="doc_subsection"><a name="software"><b>Software</b></a></div>
 358 <div class="doc_text">
 359   <p>Compiling LLVM requires that you have several software packages
 360   installed. The table below lists those required packages. The Package column
 361   is the usual name for the software package that LLVM depends on. The Version
 362   column provides "known to work" versions of the package. The Notes column
 363   describes how LLVM uses the package and provides other details.</p>
 364   <table summary="Packages required to compile LLVM">
 365     <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
 366
 367     <tr>
 368       <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
 369       <td>3.79, 3.79.1</td>
 370       <td>Makefile/build processor</td>
 371     </tr>
 372
 373     <tr>
 374       <td><a href="http://gcc.gnu.org">GCC</a></td>
 375       <td>3.4.2</td>
 376       <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
 377     </tr>
 378
 379     <tr>
 380       <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
 381       <td>4.5</td>
 382       <td>For building the CFE</td>
 383     </tr>
 384
 385     <tr>
 386       <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
 387       <td>&ge;1.3</td>
 388       <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
 389     </tr>
 390
 391     <tr>
 392       <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
 393       <td>1.4.2</td>
 394       <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
 395     </tr>
 396
 397     <tr>
 398       <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
 399       <td>8.3, 8.4</td>
 400       <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
 401     </tr>
 402
 403     <tr>
 404       <td><a href="http://expect.nist.gov/">expect</a></td>
 405       <td>5.38.0</td>
 406       <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
 407     </tr>
 408
 409     <tr>
 410       <td><a href="http://www.perl.com/download.csp">perl</a></td>
 411       <td>&ge;5.6.0</td>
 412       <td>Nightly tester, utilities</td>
 413     </tr>
 414
 415     <tr>
 416       <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
 417       <td>1.4</td>
 418       <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
 419     </tr>
 420
 421     <tr>
 422       <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
 423       <td>2.59</td>
 424       <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
 425     </tr>
 426
 427     <tr>
 428       <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
 429       <td>1.9.2</td>
 430       <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
 431     </tr>
 432
 433     <tr>
 434       <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
 435       <td>1.5.10</td>
 436       <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
 437     </tr>
 438
 439   </table>
 440
 441   <p><b>Notes:</b></p>
 442   <div class="doc_notes">
 443   <ol>
 444     <li><a name="sf1">Only the C and C++ languages are needed so there's no
 445       need to build the other languages for LLVM's purposes.</a> See
 446       <a href="#brokengcc">below</a> for specific version info.</li>
 447     <li><a name="sf2">You only need Subversion if you intend to build from the
 448       latest LLVM sources. If you're working from a release distribution, you
 449       don't need Subversion.</a></li>
 450     <li><a name="sf3">Only needed if you want to run the automated test
 451       suite in the <tt>llvm/test</tt> directory.</a></li>
 452     <li><a name="sf4">If you want to make changes to the configure scripts,
 453       you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
 454       or higher). You will also need automake (1.9.2). We only use aclocal
 455       from that package.</a></li>
 456   </ol>
 457   </div>
 458
 459   <p>Additionally, your compilation host is expected to have the usual
 460   plethora of Unix utilities. Specifically:</p>
 461   <ul>
 462     <li><b>ar</b> - archive library builder</li>
 463     <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
 464     <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
 465     <li><b>chmod</b> - change permissions on a file</li>
 466     <li><b>cat</b> - output concatenation utility</li>
 467     <li><b>cp</b> - copy files</li>
 468     <li><b>date</b> - print the current date/time </li>
 469     <li><b>echo</b> - print to standard output</li>
 470     <li><b>egrep</b> - extended regular expression search utility</li>
 471     <li><b>find</b> - find files/dirs in a file system</li>
 472     <li><b>grep</b> - regular expression search utility</li>
 473     <li><b>gzip*</b> - gzip command for distribution generation</li>
 474     <li><b>gunzip*</b> - gunzip command for distribution checking</li>
 475     <li><b>install</b> - install directories/files </li>
 476     <li><b>mkdir</b> - create a directory</li>
 477     <li><b>mv</b> - move (rename) files</li>
 478     <li><b>ranlib</b> - symbol table builder for archive libraries</li>
 479     <li><b>rm</b> - remove (delete) files and directories</li>
 480     <li><b>sed</b> - stream editor for transforming output</li>
 481     <li><b>sh</b> - Bourne shell for make build scripts</li>
 482     <li><b>tar</b> - tape archive for distribution generation</li>
 483     <li><b>test</b> - test things in file system</li>
 484     <li><b>unzip*</b> - unzip command for distribution checking</li>
 485     <li><b>zip*</b> - zip command for distribution generation</li>
 486   </ul>
 487 </div>
 488
 489 <!-- ======================================================================= -->
 490 <div class="doc_subsection">
 491   <a name="brokengcc">Broken versions of GCC and other tools</a>
 492 </div>
 493
 494 <div class="doc_text">
 495
 496 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
 497 bugs in the compiler.  In particular, several versions of GCC crash when trying
 498 to compile LLVM.  We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
 499 successfully with them (however, see important notes below).  Other versions
 500 of GCC will probably work as well.  GCC versions listed
 501 here are known to not work.  If you are using one of these versions, please try
 502 to upgrade your GCC to something more recent.  If you run into a problem with a
 503 version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
 504 us know</a>.  Please use the "<tt>gcc -v</tt>" command to find out which version
 505 of GCC you are using.
 506 </p>
 507
 508 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
 509 problems in the STL that effectively prevent it from compiling LLVM.
 510 </p>
 511
 512 <p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
 513 a bogus template error.  This was fixed in later GCCs.</p>
 514
 515 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
 516 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
 517 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
 518
 519 <p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with
 520    Cygwin does not work.  Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
 521    to a newer version</a> if possible.</p>
 522 <p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
 523    possibly others) does not compile LLVM correctly (it appears that exception
 524    handling is broken in some cases).  Please download the FSF 3.3.3 or upgrade
 525    to a newer version of GCC.</p>
 526 <p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
 527    code generator, causing an infinite loop in the llvm-gcc build when built
 528    with optimizations enabled (i.e. a release build).</p>
 529 <p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
 530    code generator at -O3, as with 3.4.0.  However gcc 3.4.2 (unlike 3.4.0)
 531    correctly compiles LLVM at -O2.  A work around is to build release LLVM
 532    builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
 533 <p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
 534    miscompiles portions of LLVM</a>.</p>
 535 <p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
 536    when building with optimizations enabled.  It appears to work with
 537    "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
 538    build.</p>
 539 <p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
 540    miscompile LLVM.</p>
 541 <p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
 542    default with ENABLE_OPTIMIZED=1.  To work around this, build with
 543    "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
 544 <p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
 545       compiling some files.  At the time of this writing, GCC mainline (4.2)
 546       did not share the problem.</p>
 547 <p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
 548    miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
 549    code.  LLVM will appear to mostly work but will be buggy, e.g. failing
 550    portions of its testsuite.</p>
 551 <p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
 552 platforms compiling md5.c gets a mangled constant.</p>
 553 <p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
 554 to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
 555 about symbols remaining in the table on destruction.</p>
 556 <p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms
 557 as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
 558 <p><b>Cygwin GCC 4.3.2 20080827 (beta) 2</b>:
 559   Users <a href="http://llvm.org/PR4145">reported</a> various problems related
 560   with link errors when using this GCC version.</p>
 561 <p><b>Debian GCC 4.3.2 on X86</b>: Crashes building some files in LLVM 2.6.</p>
 562 <p><b>GCC 4.3.3 (Debian 4.3.3-10) on ARM</b>: Miscompiles parts of LLVM 2.6
 563 when optimizations are turned on. The symptom is an infinite loop in
 564 FoldingSetImpl::RemoveNode while running the code generator.</p>
 565 <p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
 566 long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
 567 defined in a discarded section. You can safely ignore these messages as they are
 568 erroneous and the linkage is correct.  These messages disappear using ld
 569 2.17.</p>
 570
 571 <p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
 572 href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
 573 causes huge link times (minutes instead of seconds) when building LLVM.  We
 574 recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
 575
 576 <p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained
 577 <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a>
 578 which causes intermittent failures when building LLVM with position independent
 579 code.  The symptom is an error about cyclic dependencies.  We recommend
 580 upgrading to a newer version of Gold.</p>
 581
 582 </div>
 583
 584
 585
 586 <!-- *********************************************************************** -->
 587 <div class="doc_section">
 588   <a name="starting"><b>Getting Started with LLVM</b></a>
 589 </div>
 590 <!-- *********************************************************************** -->
 591
 592 <div class="doc_text">
 593
 594 <p>The remainder of this guide is meant to get you up and running with
 595 LLVM and to give you some basic information about the LLVM environment.</p>
 596
 597 <p>The later sections of this guide describe the <a
 598 href="#layout">general layout</a> of the the LLVM source tree, a <a
 599 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
 600 href="#links">links</a> to find more information about LLVM or to get
 601 help via e-mail.</p>
 602 </div>
 603
 604 <!-- ======================================================================= -->
 605 <div class="doc_subsection">
 606   <a name="terminology">Terminology and Notation</a>
 607 </div>
 608
 609 <div class="doc_text">
 610
 611 <p>Throughout this manual, the following names are used to denote paths
 612 specific to the local system and working environment.  <i>These are not
 613 environment variables you need to set but just strings used in the rest
 614 of this document below</i>.  In any of the examples below, simply replace
 615 each of these names with the appropriate pathname on your local system.
 616 All these paths are absolute:</p>
 617
 618 <dl>
 619     <dt>SRC_ROOT
 620     <dd>
 621     This is the top level directory of the LLVM source tree.
 622     <br><br>
 623
 624     <dt>OBJ_ROOT
 625     <dd>
 626     This is the top level directory of the LLVM object tree (i.e. the
 627     tree where object files and compiled programs will be placed.  It
 628     can be the same as SRC_ROOT).
 629     <br><br>
 630
 631     <dt>LLVMGCCDIR
 632     <dd>
 633     This is where the LLVM GCC Front End is installed.
 634     <p>
 635     For the pre-built GCC front end binaries, the LLVMGCCDIR is
 636     <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
 637 </dl>
 638
 639 </div>
 640
 641 <!-- ======================================================================= -->
 642 <div class="doc_subsection">
 643   <a name="environment">Setting Up Your Environment</a>
 644 </div>
 645
 646 <div class="doc_text">
 647
 648 <p>
 649 In order to compile and use LLVM, you may need to set some environment
 650 variables.
 651
 652 <dl>
 653   <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
 654   <dd>[Optional] This environment variable helps LLVM linking tools find the
 655   locations of your bitcode libraries. It is provided only as a
 656   convenience since you can specify the paths using the -L options of the
 657   tools and the C/C++ front-end will automatically use the bitcode files
 658   installed in its
 659   <tt>lib</tt> directory.</dd>
 660 </dl>
 661
 662 </div>
 663
 664 <!-- ======================================================================= -->
 665 <div class="doc_subsection">
 666   <a name="unpack">Unpacking the LLVM Archives</a>
 667 </div>
 668
 669 <div class="doc_text">
 670
 671 <p>
 672 If you have the LLVM distribution, you will need to unpack it before you
 673 can begin to compile it.  LLVM is distributed as a set of two files: the LLVM
 674 suite and the LLVM GCC front end compiled for your platform.  There is an
 675 additional test suite that is optional.  Each file is a TAR archive that is
 676 compressed with the gzip program.
 677 </p>
 678
 679 <p>The files are as follows, with <em>x.y</em> marking the version number:
 680 <dl>
 681   <dt><tt>llvm-x.y.tar.gz</tt></dt>
 682   <dd>Source release for the LLVM libraries and tools.<br></dd>
 683
 684   <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
 685   <dd>Source release for the LLVM test suite.</dd>
 686
 687   <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt>
 688   <dd>Source release of the llvm-gcc-4.2 front end.  See README.LLVM in the root
 689       directory for build instructions.<br></dd>
 690
 691   <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt>
 692   <dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd>
 693
 694 </dl>
 695
 696 </div>
 697
 698 <!-- ======================================================================= -->
 699 <div class="doc_subsection">
 700   <a name="checkout">Checkout LLVM from Subversion</a>
 701 </div>
 702
 703 <div class="doc_text">
 704
 705 <p>If you have access to our Subversion repository, you can get a fresh copy of
 706 the entire source code.  All you need to do is check it out from Subversion as
 707 follows:</p>
 708
 709 <ul>
 710   <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
 711   <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
 712   <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
 713     llvm</tt></li>
 714 </ul>
 715
 716
 717 <p>This will create an '<tt>llvm</tt>' directory in the current
 718 directory and fully populate it with the LLVM source code, Makefiles,
 719 test directories, and local copies of documentation files.</p>
 720
 721 <p>If you want to get a specific release (as opposed to the most recent
 722 revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
 723 '<tt>trunk</tt>'). The following releases are located in the following
 724 subdirectories of the '<tt>tags</tt>' directory:</p>
 725
 726 <ul>
 727 <li>Release 2.5: <b>RELEASE_25</b></li>
 728 <li>Release 2.4: <b>RELEASE_24</b></li>
 729 <li>Release 2.3: <b>RELEASE_23</b></li>
 730 <li>Release 2.2: <b>RELEASE_22</b></li>
 731 <li>Release 2.1: <b>RELEASE_21</b></li>
 732 <li>Release 2.0: <b>RELEASE_20</b></li>
 733 <li>Release 1.9: <b>RELEASE_19</b></li>
 734 <li>Release 1.8: <b>RELEASE_18</b></li>
 735 <li>Release 1.7: <b>RELEASE_17</b></li>
 736 <li>Release 1.6: <b>RELEASE_16</b></li>
 737 <li>Release 1.5: <b>RELEASE_15</b></li>
 738 <li>Release 1.4: <b>RELEASE_14</b></li>
 739 <li>Release 1.3: <b>RELEASE_13</b></li>
 740 <li>Release 1.2: <b>RELEASE_12</b></li>
 741 <li>Release 1.1: <b>RELEASE_11</b></li>
 742 <li>Release 1.0: <b>RELEASE_1</b></li>
 743 </ul>
 744
 745 <p>If you would like to get the LLVM test suite (a separate package as of 1.4),
 746 you get it from the Subversion repository:</p>
 747
 748 <div class="doc_code">
 749 <pre>
 750 % cd llvm/projects
 751 % svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
 752 </pre>
 753 </div>
 754
 755 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
 756 configured by the LLVM configure script as well as automatically updated when
 757 you run <tt>svn update</tt>.</p>
 758
 759 <p>If you would like to get the GCC front end source code, you can also get it
 760 and build it yourself.  Please follow <a href="GCCFEBuildInstrs.html">these
 761 instructions</a> to successfully get and build the LLVM GCC front-end.</p>
 762
 763 </div>
 764
 765 <!-- ======================================================================= -->
 766 <div class="doc_subsection">
 767   <a name="installcf">Install the GCC Front End</a>
 768 </div>
 769
 770 <div class="doc_text">
 771
 772 <p>Before configuring and compiling the LLVM suite, you can optionally extract the
 773 LLVM GCC front end from the binary distribution.  It is used for running the
 774 llvm-test testsuite and for compiling C/C++ programs.  Note that you can optionally
 775 <a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
 776 main LLVM repository.</p>
 777
 778 <p>To install the GCC front end, do the following:</p>
 779
 780 <ol>
 781   <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
 782   <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf
 783       -</tt></li>
 784 </ol>
 785
 786 <p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
 787 llvm-g++ to some directory in your path.  When you configure LLVM, it will
 788 automatically detect llvm-gcc's presence (if it is in your path) enabling its
 789 use in llvm-test.  Note that you can always build or install llvm-gcc at any
 790 pointer after building the main LLVM repository: just reconfigure llvm and
 791 llvm-test will pick it up.
 792 </p>
 793
 794 <p>The binary versions of the GCC front end may not suit all of your needs.  For
 795 example, the binary distribution may include an old version of a system header
 796 file, not "fix" a header file that needs to be fixed for GCC, or it may be
 797 linked with libraries not available on your system.</p>
 798
 799 <p>In cases like these, you may want to try <a
 800 href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
 801 much easier now than it was in the past.</p>
 802
 803 </div>
 804
 805 <!-- ======================================================================= -->
 806 <div class="doc_subsection">
 807   <a name="config">Local LLVM Configuration</a>
 808 </div>
 809
 810 <div class="doc_text">
 811
 812   <p>Once checked out from the Subversion repository, the LLVM suite source
 813   code must be
 814 configured via the <tt>configure</tt> script.  This script sets variables in the
 815 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
 816 <tt>llvm/include/Config/config.h</tt>.  It also populates <i>OBJ_ROOT</i> with
 817 the Makefiles needed to begin building LLVM.</p>
 818
 819 <p>The following environment variables are used by the <tt>configure</tt>
 820 script to configure the build system:</p>
 821
 822 <table summary="LLVM configure script environment variables">
 823   <tr><th>Variable</th><th>Purpose</th></tr>
 824   <tr>
 825     <td>CC</td>
 826     <td>Tells <tt>configure</tt> which C compiler to use.  By default,
 827         <tt>configure</tt> will look for the first GCC C compiler in
 828         <tt>PATH</tt>.  Use this variable to override
 829         <tt>configure</tt>'s default behavior.</td>
 830   </tr>
 831   <tr>
 832     <td>CXX</td>
 833     <td>Tells <tt>configure</tt> which C++ compiler to use.  By default,
 834        <tt>configure</tt> will look for the first GCC C++ compiler in
 835        <tt>PATH</tt>.  Use this variable to override
 836        <tt>configure</tt>'s default behavior.</td>
 837   </tr>
 838 </table>
 839
 840 <p>The following options can be used to set or enable LLVM specific options:</p>
 841
 842 <dl>
 843   <dt><i>--with-llvmgccdir</i></dt>
 844   <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
 845   The value of this option should specify the full pathname of the C/C++ Front
 846   End to be used. If this option is not provided, the PATH will be searched for
 847   a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
 848   be inferred from the path found. If the option is not given, and no llvm-gcc
 849   can be found in the path then a warning will be produced by
 850   <tt>configure</tt> indicating this situation. LLVM may still be built with
 851   the <tt>tools-only</tt> target but attempting to build the runtime libraries
 852   will fail as these libraries require llvm-gcc and llvm-g++. See
 853   <a href="#installcf">Install the GCC Front End</a> for details on installing
 854   the C/C++ Front End. See
 855   <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
 856   for details on building the C/C++ Front End.</dd>
 857   <dt><i>--with-tclinclude</i></dt>
 858   <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
 859   found. Use this if you have multiple tcl installations on your machine and you
 860   want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
 861   dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
 862   option, the LLVM configure script will search for the tcl 8.4 and 8.3
 863   releases.
 864   <br><br>
 865   </dd>
 866   <dt><i>--enable-optimized</i></dt>
 867   <dd>
 868     Enables optimized compilation (debugging symbols are removed
 869     and GCC optimization flags are enabled). Note that this is the default
 870     setting     if you are using the LLVM distribution. The default behavior
 871     of an Subversion checkout is to use an unoptimized build (also known as a
 872     debug build).
 873     <br><br>
 874   </dd>
 875   <dt><i>--enable-debug-runtime</i></dt>
 876   <dd>
 877     Enables debug symbols in the runtime libraries. The default is to strip
 878     debug symbols from the runtime libraries.
 879   </dd>
 880   <dt><i>--enable-jit</i></dt>
 881   <dd>
 882     Compile the Just In Time (JIT) compiler functionality.  This is not
 883     available
 884     on all platforms.  The default is dependent on platform, so it is best
 885     to explicitly enable it if you want it.
 886     <br><br>
 887   </dd>
 888   <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
 889   <dd>Controls which targets will be built and linked into llc. The default
 890   value for <tt>target_options</tt> is "all" which builds and links all
 891   available targets.  The value "host-only" can be specified to build only a
 892   native compiler (no cross-compiler targets available). The "native" target is
 893   selected as the target of the build host. You can also specify a comma
 894   separated list of target names that you want available in llc. The target
 895   names use all lower case. The current set of targets is: <br>
 896   <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
 897   <br><br></dd>
 898   <dt><i>--enable-doxygen</i></dt>
 899   <dd>Look for the doxygen program and enable construction of doxygen based
 900   documentation from the source code. This is disabled by default because
 901   generating the documentation can take a long time and producess 100s of
 902   megabytes of output.</dd>
 903   <dt><i>--with-udis86</i></dt>
 904   <dd>LLVM can use external disassembler library for various purposes (now it's
 905   used only for examining code produced by JIT). This option will enable usage
 906   of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
 907   bits) disassembler library.</dd>
 908 </dl>
 909
 910 <p>To configure LLVM, follow these steps:</p>
 911
 912 <ol>
 913     <li><p>Change directory into the object root directory:</p>
 914
 915     <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
 916
 917     <li><p>Run the <tt>configure</tt> script located in the LLVM source
 918     tree:</p>
 919
 920     <div class="doc_code">
 921     <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
 922     </div></li>
 923 </ol>
 924
 925 </div>
 926
 927 <!-- ======================================================================= -->
 928 <div class="doc_subsection">
 929   <a name="compile">Compiling the LLVM Suite Source Code</a>
 930 </div>
 931
 932 <div class="doc_text">
 933
 934 <p>Once you have configured LLVM, you can build it.  There are three types of
 935 builds:</p>
 936
 937 <dl>
 938     <dt>Debug Builds
 939     <dd>
 940     These builds are the default when one is using an Subversion checkout and
 941     types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was
 942     used during configuration).  The build system will compile the tools and
 943     libraries with debugging information.  To get a Debug Build using the
 944     LLVM distribution the <tt>--disable-optimized</tt> option must be passed
 945     to <tt>configure</tt>.
 946     <br><br>
 947
 948     <dt>Release (Optimized) Builds
 949     <dd>
 950     These builds are enabled with the <tt>--enable-optimized</tt> option to
 951     <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
 952     <tt>gmake</tt> command line.  For these builds, the build system will
 953     compile the tools and libraries with GCC optimizations enabled and strip
 954     debugging information from the libraries and executables it generates.
 955     Note that Release Builds are default when using an LLVM distribution.
 956     <br><br>
 957
 958     <dt>Profile Builds
 959     <dd>
 960     These builds are for use with profiling.  They compile profiling
 961     information into the code for use with programs like <tt>gprof</tt>.
 962     Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
 963     on the <tt>gmake</tt> command line.
 964 </dl>
 965
 966 <p>Once you have LLVM configured, you can build it by entering the
 967 <i>OBJ_ROOT</i> directory and issuing the following command:</p>
 968
 969 <div class="doc_code"><pre>% gmake</pre></div>
 970
 971 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
 972 are using a version of GCC that is known not to compile LLVM.</p>
 973
 974 <p>
 975 If you have multiple processors in your machine, you may wish to use some of
 976 the parallel build options provided by GNU Make.  For example, you could use the
 977 command:</p>
 978
 979 <div class="doc_code"><pre>% gmake -j2</pre></div>
 980
 981 <p>There are several special targets which are useful when working with the LLVM
 982 source code:</p>
 983
 984 <dl>
 985   <dt><tt>gmake clean</tt>
 986   <dd>
 987   Removes all files generated by the build.  This includes object files,
 988   generated C/C++ files, libraries, and executables.
 989   <br><br>
 990
 991   <dt><tt>gmake dist-clean</tt>
 992   <dd>
 993   Removes everything that <tt>gmake clean</tt> does, but also removes files
 994   generated by <tt>configure</tt>.  It attempts to return the source tree to the
 995   original state in which it was shipped.
 996   <br><br>
 997
 998   <dt><tt>gmake install</tt>
 999   <dd>
1000   Installs LLVM header files, libraries, tools, and documentation in a
1001   hierarchy
1002   under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
1003   defaults to <tt>/usr/local</tt>.
1004   <br><br>
1005
1006   <dt><tt>gmake -C runtime install-bytecode</tt>
1007   <dd>
1008   Assuming you built LLVM into $OBJDIR, when this command is run, it will
1009   install bitcode libraries into the GCC front end's bitcode library
1010   directory.  If you need to update your bitcode libraries,
1011   this is the target to use once you've built them.
1012   <br><br>
1013 </dl>
1014
1015 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
1016 details on these <tt>make</tt> targets and descriptions of other targets
1017 available.</p>
1018
1019 <p>It is also possible to override default values from <tt>configure</tt> by
1020 declaring variables on the command line.  The following are some examples:</p>
1021
1022 <dl>
1023   <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1024   <dd>
1025   Perform a Release (Optimized) build.
1026   <br><br>
1027
1028   <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1029   <dd>
1030   Perform a Release (Optimized) build without assertions enabled.
1031   <br><br>
1032
1033   <dt><tt>gmake ENABLE_OPTIMIZED=0</tt>
1034   <dd>
1035   Perform a Debug build.
1036   <br><br>
1037
1038   <dt><tt>gmake ENABLE_PROFILING=1</tt>
1039   <dd>
1040   Perform a Profiling build.
1041   <br><br>
1042
1043   <dt><tt>gmake VERBOSE=1</tt>
1044   <dd>
1045   Print what <tt>gmake</tt> is doing on standard output.
1046   <br><br>
1047
1048   <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1049   <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1050   the standard output. This also implies <tt>VERBOSE=1</tt>.
1051   <br><br></dd>
1052 </dl>
1053
1054 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1055 it and any subdirectories that it contains.  Entering any directory inside the
1056 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1057 that directory that is out of date.</p>
1058
1059 </div>
1060
1061 <!-- ======================================================================= -->
1062 <div class="doc_subsection">
1063   <a name="cross-compile">Cross-Compiling LLVM</a>
1064 </div>
1065
1066 <div class="doc_text">
1067   <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
1068   executables and libraries to be hosted on a platform different from the
1069   platform where they are build (a Canadian Cross build). To configure a
1070   cross-compile, supply the configure script with <tt>--build</tt> and
1071   <tt>--host</tt> options that are different. The values of these options must
1072   be legal target triples that your GCC compiler supports.</p>
1073
1074   <p>The result of such a build is executables that are not runnable on
1075   on the build host (--build option) but can be executed on the compile host
1076   (--host option).</p>
1077 </div>
1078
1079 <!-- ======================================================================= -->
1080 <div class="doc_subsection">
1081   <a name="objfiles">The Location of LLVM Object Files</a>
1082 </div>
1083
1084 <div class="doc_text">
1085
1086 <p>The LLVM build system is capable of sharing a single LLVM source tree among
1087 several LLVM builds.  Hence, it is possible to build LLVM for several different
1088 platforms or configurations using the same source tree.</p>
1089
1090 <p>This is accomplished in the typical autoconf manner:</p>
1091
1092 <ul>
1093   <li><p>Change directory to where the LLVM object files should live:</p>
1094
1095       <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1096
1097   <li><p>Run the <tt>configure</tt> script found in the LLVM source
1098       directory:</p>
1099
1100       <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1101 </ul>
1102
1103 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1104 named after the build type:</p>
1105
1106 <dl>
1107   <dt>Debug Builds
1108   <dd>
1109   <dl>
1110     <dt>Tools
1111     <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1112     <dt>Libraries
1113     <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1114   </dl>
1115   <br><br>
1116
1117   <dt>Release Builds
1118   <dd>
1119   <dl>
1120     <dt>Tools
1121     <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1122     <dt>Libraries
1123     <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1124   </dl>
1125   <br><br>
1126
1127   <dt>Profile Builds
1128   <dd>
1129   <dl>
1130     <dt>Tools
1131     <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1132     <dt>Libraries
1133     <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1134   </dl>
1135 </dl>
1136
1137 </div>
1138
1139 <!-- ======================================================================= -->
1140 <div class="doc_subsection">
1141   <a name="optionalconfig">Optional Configuration Items</a>
1142 </div>
1143
1144 <div class="doc_text">
1145
1146 <p>
1147 If you're running on a Linux system that supports the "<a
1148 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1149 module, and you have root access on the system, you can set your system up to
1150 execute LLVM bitcode files directly. To do this, use commands like this (the
1151 first command may not be required if you are already using the module):</p>
1152
1153 <div class="doc_code">
1154 <pre>
1155 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1156 $ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1157 $ chmod u+x hello.bc   (if needed)
1158 $ ./hello.bc
1159 </pre>
1160 </div>
1161
1162 <p>
1163 This allows you to execute LLVM bitcode files directly.  Thanks to Jack
1164 Cummings for pointing this out!
1165 </p>
1166
1167 </div>
1168
1169
1170 <!-- *********************************************************************** -->
1171 <div class="doc_section">
1172   <a name="layout"><b>Program Layout</b></a>
1173 </div>
1174 <!-- *********************************************************************** -->
1175
1176 <div class="doc_text">
1177
1178 <p>One useful source of information about the LLVM source base is the LLVM <a
1179 href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1180 href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1181 The following is a brief introduction to code layout:</p>
1182
1183 </div>
1184
1185 <!-- ======================================================================= -->
1186 <div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1187 <div class="doc_text">
1188   <p>This directory contains some simple examples of how to use the LLVM IR and
1189   JIT.</p>
1190 </div>
1191
1192 <!-- ======================================================================= -->
1193 <div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1194 <div class="doc_text">
1195
1196 <p>This directory contains public header files exported from the LLVM
1197 library. The three main subdirectories of this directory are:</p>
1198
1199 <dl>
1200   <dt><tt><b>llvm/include/llvm</b></tt></dt>
1201   <dd>This directory contains all of the LLVM specific header files.  This
1202   directory also has subdirectories for different portions of LLVM:
1203   <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1204   etc...</dd>
1205
1206   <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1207   <dd>This directory contains generic support libraries that are provided with
1208   LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1209   and a Command Line option processing library store their header files here.
1210   </dd>
1211
1212   <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1213   <dd>This directory contains header files configured by the <tt>configure</tt>
1214   script.  They wrap "standard" UNIX and C header files.  Source code can
1215   include these header files which automatically take care of the conditional
1216   #includes that the <tt>configure</tt> script generates.</dd>
1217 </dl>
1218 </div>
1219
1220 <!-- ======================================================================= -->
1221 <div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1222 <div class="doc_text">
1223
1224 <p>This directory contains most of the source files of the LLVM system. In LLVM,
1225 almost all code exists in libraries, making it very easy to share code among the
1226 different <a href="#tools">tools</a>.</p>
1227
1228 <dl>
1229   <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1230   <dd> This directory holds the core LLVM source files that implement core
1231   classes like Instruction and BasicBlock.</dd>
1232
1233   <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1234   <dd>This directory holds the source code for the LLVM assembly language parser
1235   library.</dd>
1236
1237   <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1238   <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1239
1240   <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1241   different program analyses, such as Dominator Information, Call Graphs,
1242   Induction Variables, Interval Identification, Natural Loop Identification,
1243   etc.</dd>
1244
1245   <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1246   <dd> This directory contains the source code for the LLVM to LLVM program
1247   transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1248   Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1249   Elimination, and many others.</dd>
1250
1251   <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1252   <dd> This directory contains files that describe various target architectures
1253   for code generation.  For example, the <tt>llvm/lib/Target/X86</tt>
1254   directory holds the X86 machine description while
1255   <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1256
1257   <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1258   <dd> This directory contains the major parts of the code generator: Instruction
1259   Selector, Instruction Scheduling, and Register Allocation.</dd>
1260
1261   <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1262   <dd> This directory contains the source level debugger library that makes
1263   it possible to instrument LLVM programs so that a debugger could identify
1264   source code locations at which the program is executing.</dd>
1265
1266   <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1267   <dd> This directory contains libraries for executing LLVM bitcode directly
1268   at runtime in both interpreted and JIT compiled fashions.</dd>
1269
1270   <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1271   <dd> This directory contains the source code that corresponds to the header
1272   files located in <tt>llvm/include/Support/</tt>.</dd>
1273
1274   <dt><tt><b>llvm/lib/System/</b></tt></dt>
1275   <dd>This directory contains the operating system abstraction layer that
1276   shields LLVM from platform-specific coding.</dd>
1277 </dl>
1278
1279 </div>
1280
1281 <!-- ======================================================================= -->
1282 <div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1283 <div class="doc_text">
1284   <p>This directory contains projects that are not strictly part of LLVM but are
1285   shipped with LLVM. This is also the directory where you should create your own
1286   LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1287   to set up your own project.</p>
1288 </div>
1289
1290 <!-- ======================================================================= -->
1291 <div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1292 <div class="doc_text">
1293
1294 <p>This directory contains libraries which are compiled into LLVM bitcode and
1295 used when linking programs with the GCC front end.  Most of these libraries are
1296 skeleton versions of real libraries; for example, libc is a stripped down
1297 version of glibc.</p>
1298
1299 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1300 end to compile.</p>
1301
1302 </div>
1303
1304 <!-- ======================================================================= -->
1305 <div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1306 <div class="doc_text">
1307   <p>This directory contains feature and regression tests and other basic sanity
1308   checks on the LLVM infrastructure. These are intended to run quickly and cover
1309   a lot of territory without being exhaustive.</p>
1310 </div>
1311
1312 <!-- ======================================================================= -->
1313 <div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1314 <div class="doc_text">
1315   <p>This is not a directory in the normal llvm module; it is a separate
1316   Subversion
1317   module that must be checked out (usually to <tt>projects/test-suite</tt>).
1318   This
1319   module contains a comprehensive correctness, performance, and benchmarking
1320   test
1321   suite for LLVM. It is a separate Subversion module because not every LLVM
1322   user is
1323   interested in downloading or building such a comprehensive test suite. For
1324   further details on this test suite, please see the
1325   <a href="TestingGuide.html">Testing Guide</a> document.</p>
1326 </div>
1327
1328 <!-- ======================================================================= -->
1329 <div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1330 <div class="doc_text">
1331
1332 <p>The <b>tools</b> directory contains the executables built out of the
1333 libraries above, which form the main part of the user interface.  You can
1334 always get help for a tool by typing <tt>tool_name --help</tt>.  The
1335 following is a brief introduction to the most important tools.  More detailed
1336 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1337
1338 <dl>
1339
1340   <dt><tt><b>bugpoint</b></tt></dt>
1341   <dd><tt>bugpoint</tt> is used to debug
1342   optimization passes or code generation backends by narrowing down the
1343   given test case to the minimum number of passes and/or instructions that
1344   still cause a problem, whether it is a crash or miscompilation. See <a
1345   href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1346   on using <tt>bugpoint</tt>.</dd>
1347
1348   <dt><tt><b>llvmc</b></tt></dt>
1349   <dd>The LLVM Compiler Driver. This program can
1350   be configured to utilize both LLVM and non-LLVM compilation tools to enable
1351   pre-processing, translation, optimization, assembly, and linking of programs
1352   all from one command line. <tt>llvmc</tt> also takes care of processing the
1353   dependent libraries found in bitcode. This reduces the need to get the
1354   traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1355   note that this tool, while functional, is still experimental and not feature
1356   complete.</dd>
1357
1358   <dt><tt><b>llvm-ar</b></tt></dt>
1359   <dd>The archiver produces an archive containing
1360   the given LLVM bitcode files, optionally with an index for faster
1361   lookup.</dd>
1362
1363   <dt><tt><b>llvm-as</b></tt></dt>
1364   <dd>The assembler transforms the human readable LLVM assembly to LLVM
1365   bitcode.</dd>
1366
1367   <dt><tt><b>llvm-dis</b></tt></dt>
1368   <dd>The disassembler transforms the LLVM bitcode to human readable
1369   LLVM assembly.</dd>
1370
1371   <dt><tt><b>llvm-ld</b></tt></dt>
1372   <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1373   This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1374   optimizations and allows optimization modules to be loaded and run so that
1375   language specific optimizations can be applied at link time.</dd>
1376
1377   <dt><tt><b>llvm-link</b></tt></dt>
1378   <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1379   a single program.</dd>
1380
1381   <dt><tt><b>lli</b></tt></dt>
1382   <dd><tt>lli</tt> is the LLVM interpreter, which
1383   can directly execute LLVM bitcode (although very slowly...). For architectures
1384   that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1385   will function as a Just-In-Time compiler (if the functionality was compiled
1386   in), and will execute the code <i>much</i> faster than the interpreter.</dd>
1387
1388   <dt><tt><b>llc</b></tt></dt>
1389   <dd> <tt>llc</tt> is the LLVM backend compiler, which
1390   translates LLVM bitcode to a native code assembly file or to C code (with
1391   the -march=c option).</dd>
1392
1393   <dt><tt><b>llvm-gcc</b></tt></dt>
1394   <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1395   use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1396   bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1397   usual machine code output.  It works just like any other GCC compiler,
1398   taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1399   Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1400   separate Subversion module.</dd>
1401
1402   <dt><tt><b>opt</b></tt></dt>
1403   <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1404   transformations (which are specified on the command line), and then outputs
1405   the resultant bitcode.  The '<tt>opt --help</tt>' command is a good way to
1406   get a list of the program transformations available in LLVM.<br>
1407   <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1408   LLVM bitcode file and print out the results.  It is primarily useful for
1409   debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1410 </dl>
1411 </div>
1412
1413 <!-- ======================================================================= -->
1414 <div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1415 <div class="doc_text">
1416
1417 <p>This directory contains utilities for working with LLVM source code, and some
1418 of the utilities are actually required as part of the build process because they
1419 are code generators for parts of LLVM infrastructure.</p>
1420
1421 <dl>
1422   <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1423   that finds differences between code that LLC generates and code that LLI
1424   generates. This is a useful tool if you are debugging one of them,
1425   assuming that the other generates correct output. For the full user
1426   manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1427
1428   <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1429   syntax-highlighting files which will work with Emacs and XEmacs editors,
1430   providing syntax highlighting support for LLVM assembly files and TableGen
1431   description files. For information on how to use the syntax files, consult
1432   the <tt>README</tt> file in that directory.<br><br>
1433
1434   <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1435   and outputs all non-generated source files, which is useful if one wishes
1436   to do a lot of development across directories and does not want to
1437   individually find each file. One way to use it is to run, for example:
1438   <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1439   tree.<br><br>
1440
1441   <dt><tt><b>llvmgrep</b></tt></dt>
1442   <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1443   passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1444   line. This is a very efficient way of searching the source base for a
1445   particular regular expression.</dd>
1446
1447   <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1448   files in the current directory and then compiles and links the tool that
1449   is the first argument. For example, assuming you are in the directory
1450   <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1451   simply running <tt>makellvm llc</tt> will make a build of the current
1452   directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1453   causing a re-linking of LLC.<br><br>
1454
1455   <dt><tt><b>NewNightlyTest.pl</b></tt> and
1456   <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1457   cron script to generate nightly status reports of the functionality of
1458   tools, and the results can be seen by following the appropriate link on
1459   the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1460
1461   <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1462   the tool used to generate register descriptions, instruction set
1463   descriptions, and even assemblers from common TableGen description
1464   files.<br><br>
1465
1466   <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1467   syntax-highlighting files which will work with the VIM editor, providing
1468   syntax highlighting support for LLVM assembly files and TableGen
1469   description files. For information on how to use the syntax files, consult
1470   the <tt>README</tt> file in that directory.<br><br>
1471
1472 </dl>
1473
1474 </div>
1475
1476 <!-- ======================================================================= -->
1477 <div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1478 <div class="doc_text">
1479   <p>This directory contains build scripts and project files for use with
1480   Visual C++. This allows developers on Windows to build LLVM without the need
1481   for Cygwin. The contents of this directory should be considered experimental
1482   at this time.
1483   </p>
1484 </div>
1485 <!-- *********************************************************************** -->
1486 <div class="doc_section">
1487   <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1488 </div>
1489 <!-- *********************************************************************** -->
1490
1491 <div class="doc_text">
1492 <p>This section gives an example of using LLVM.  llvm-gcc3 is now obsolete,
1493 so we only include instructions for llvm-gcc4.
1494 </p>
1495
1496 <p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1497 from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1498 create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1499 the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1500 <i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1501 output.</p>
1502 </div>
1503
1504 <!-- ======================================================================= -->
1505 <div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1506
1507 <div class="doc_text">
1508
1509 <ol>
1510   <li><p>First, create a simple C file, name it 'hello.c':</p>
1511
1512 <div class="doc_code">
1513 <pre>
1514 #include &lt;stdio.h&gt;
1515
1516 int main() {
1517   printf("hello world\n");
1518   return 0;
1519 }
1520 </pre></div></li>
1521
1522   <li><p>Next, compile the C file into a native executable:</p>
1523
1524       <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1525
1526       <p>Note that llvm-gcc works just like GCC by default.  The standard -S and
1527         -c arguments work as usual (producing a native .s or .o file,
1528         respectively).</p></li>
1529
1530   <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1531
1532       <div class="doc_code">
1533       <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1534
1535       <p>The -emit-llvm option can be used with the -S or -c options to emit an
1536          LLVM ".ll" or ".bc" file (respectively) for the code.  This allows you
1537          to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1538          the bitcode file.</p>
1539
1540       <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1541          </p></li>
1542
1543   <li><p>Run the program in both forms. To run the program, use:</p>
1544
1545       <div class="doc_code"><pre>% ./hello</pre></div>
1546
1547       <p>and</p>
1548
1549       <div class="doc_code"><pre>% lli hello.bc</pre></div>
1550
1551       <p>The second examples shows how to invoke the LLVM JIT, <a
1552        href="CommandGuide/html/lli.html">lli</a>.</p></li>
1553
1554   <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1555       code:</p>
1556
1557 <div class="doc_code">
1558 <pre>llvm-dis &lt; hello.bc | less</pre>
1559 </div></li>
1560
1561   <li><p>Compile the program to native assembly using the LLC code
1562       generator:</p>
1563
1564       <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1565
1566   <li><p>Assemble the native assembly language file into a program:</p>
1567
1568 <div class="doc_code">
1569 <pre>
1570 <b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1571
1572 <b>Others:</b>  % gcc hello.s -o hello.native
1573 </pre>
1574 </div></li>
1575
1576   <li><p>Execute the native code program:</p>
1577
1578       <div class="doc_code"><pre>% ./hello.native</pre></div>
1579
1580       <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1581          the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1582         </li>
1583
1584 </ol>
1585
1586 </div>
1587
1588
1589 <!-- *********************************************************************** -->
1590 <div class="doc_section">
1591   <a name="problems">Common Problems</a>
1592 </div>
1593 <!-- *********************************************************************** -->
1594
1595 <div class="doc_text">
1596
1597 <p>If you are having problems building or using LLVM, or if you have any other
1598 general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1599 Asked Questions</a> page.</p>
1600
1601 </div>
1602
1603 <!-- *********************************************************************** -->
1604 <div class="doc_section">
1605   <a name="links">Links</a>
1606 </div>
1607 <!-- *********************************************************************** -->
1608
1609 <div class="doc_text">
1610
1611 <p>This document is just an <b>introduction</b> on how to use LLVM to do
1612 some simple things... there are many more interesting and complicated things
1613 that you can do that aren't documented here (but we'll gladly accept a patch
1614 if you want to write something up!).  For more information about LLVM, check
1615 out:</p>
1616
1617 <ul>
1618   <li><a href="http://llvm.org/">LLVM homepage</a></li>
1619   <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1620   <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1621   that Uses LLVM</a></li>
1622 </ul>
1623
1624 </div>
1625
1626 <!-- *********************************************************************** -->
1627
1628 <hr>
1629 <address>
1630   <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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1633   src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
1634
1635   <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1636   <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1637   <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
1638   Last modified: $Date$
1639 </address>
1640 </body>
1641 </html>