docs/GettingStarted.html

   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
   2                       "http://www.w3.org/TR/html4/strict.dtd">
   3 <html>
   4 <head>
   5   <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
   6   <title>Getting Started with LLVM System</title>
   7   <link rel="stylesheet" href="llvm.css" type="text/css">
   8 </head>
   9 <body>
  10
  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.</p></li>
 163         <li><tt>--enable-spec2000=<i>directory</i></tt>
 164             <p>Enable the SPEC2000 benchmarks for testing.  The SPEC2000
 165             benchmarks should be available in
 166             <tt><i>directory</i></tt>.</p></li>
 167       </ul>
 168   </ol></li>
 169
 170   <li>Build the LLVM Suite:
 171   <ol>
 172       <li><tt>gmake -k |&amp; tee gnumake.out
 173       &nbsp;&nbsp;&nbsp;# this is csh or tcsh syntax</tt></li>
 174       <li>If you get an "internal compiler error (ICE)" or test failures, see
 175           <a href="#brokengcc">below</a>.</li>
 176   </ol>
 177
 178 </ol>
 179
 180 <p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
 181 detailed information on configuring and compiling LLVM.  See <a
 182 href="#environment">Setting Up Your Environment</a> for tips that simplify
 183 working with the GCC front end and LLVM tools.  Go to <a href="#layout">Program
 184 Layout</a> to learn about the layout of the source code tree.</p>
 185
 186 </div>
 187
 188 <!-- *********************************************************************** -->
 189 <div class="doc_section">
 190   <a name="requirements"><b>Requirements</b></a>
 191 </div>
 192 <!-- *********************************************************************** -->
 193
 194 <div class="doc_text">
 195
 196 <p>Before you begin to use the LLVM system, review the requirements given below.
 197 This may save you some trouble by knowing ahead of time what hardware and
 198 software you will need.</p>
 199
 200 </div>
 201
 202 <!-- ======================================================================= -->
 203 <div class="doc_subsection">
 204   <a name="hardware"><b>Hardware</b></a>
 205 </div>
 206
 207 <div class="doc_text">
 208
 209 <p>LLVM is known to work on the following platforms:</p>
 210
 211 <table cellpadding="3" summary="Known LLVM platforms">
 212 <tr>
 213   <th>OS</th>
 214   <th>Arch</th>
 215   <th>Compilers</th>
 216 </tr>
 217 <tr>
 218   <td>Linux</td>
 219   <td>x86<sup><a href="#pf_1">1</a></sup></td>
 220   <td>GCC</td>
 221 </tr>
 222 <tr>
 223   <td>Solaris</td>
 224   <td>V9 (Ultrasparc)</td>
 225   <td>GCC</td>
 226 </tr>
 227 <tr>
 228   <td>FreeBSD</td>
 229   <td>x86<sup><a href="#pf_1">1</a></sup></td>
 230   <td>GCC</td>
 231 </tr>
 232 <tr>
 233   <td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
 234   <td>PowerPC</td>
 235   <td>GCC</td>
 236 </tr>
 237 <tr>
 238   <td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td>
 239   <td>x86</td>
 240   <td>GCC</td>
 241
 242 </tr>
 243 <tr>
 244   <td>Cygwin/Win32</td>
 245   <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a></sup></td>
 246   <td>GCC 3.4.X, binutils 2.15</td>
 247 </tr>
 248 <tr>
 249   <td>MinGW/Win32</td>
 250   <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,<a href="#pf_8">8</a></sup></td>
 251   <td>GCC 3.4.X, binutils 2.15</td>
 252 </tr>
 253 <tr>
 254   <td>Linux</td>
 255   <td>amd64</td>
 256   <td>GCC</td>
 257 </tr>
 258 </table>
 259
 260 <p>LLVM has partial support for the following platforms:</p>
 261
 262 <table summary="LLVM partial platform support">
 263 <tr>
 264   <th>OS</th>
 265   <th>Arch</th>
 266   <th>Compilers</th>
 267 </tr>
 268 <tr>
 269   <td>Windows</td>
 270   <td>x86<sup><a href="#pf_1">1</a></sup></td>
 271   <td>Visual Studio 2005 SP1 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
 272 <tr>
 273   <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
 274   <td>PowerPC</td>
 275   <td>GCC</td>
 276 </tr>
 277 <tr>
 278   <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
 279   <td>PowerPC</td>
 280   <td>GCC</td>
 281 </tr>
 282
 283 <tr>
 284   <td>Linux<sup><a href="#pf_7">7</a></sup></td>
 285   <td>Alpha</td>
 286   <td>GCC</td>
 287 </tr>
 288 <tr>
 289   <td>Linux<sup><a href="#pf_7">7</a></sup></td>
 290   <td>Itanium (IA-64)</td>
 291   <td>GCC</td>
 292 </tr>
 293 <tr>
 294   <td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
 295   <td>Itanium (IA-64)</td>
 296   <td>HP aCC</td>
 297 </tr>
 298 </table>
 299
 300 <p><b>Notes:</b></p>
 301
 302 <div class="doc_notes">
 303 <ol>
 304 <li><a name="pf_1">Code generation supported for Pentium processors and
 305 up</a></li>
 306 <li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
 307 <li><a name="pf_3">No native code generation</a></li>
 308 <li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li>
 309 <li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
 310 <li><a name="pf_6">The port is done using the MSYS shell.</a></li>
 311 <li><a name="pf_7">Native code generation exists but is not complete.</a></li>
 312 <li><a name="pf_8">Binutils</a> up to post-2.17 has bug in bfd/cofflink.c
 313     preventing LLVM from building correctly. Several workarounds have been
 314     introduced into LLVM build system, but the bug can occur anytime in the
 315     future. We highly recommend that you rebuild your current binutils with the
 316     patch from <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=2659">
 317     Binutils bugzilla</a>, if it wasn't already applied.</li>
 318 <li><a name="pf_9">XCode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip
 319     internal LLVM assert messages when compiled for Release at optimization
 320     levels greater than 0 (i.e., <i>"-O1"</i> and higher).
 321     Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
 322     if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
 323 </ol>
 324 </div>
 325
 326 <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
 327 mode, depending on the system (it is so large because of all the debugging
 328 information and the fact that the libraries are statically linked into multiple
 329 tools).  If you do not need many of the tools and you are space-conscious,
 330 you can disable them individually in <tt>llvm/tools/Makefile</tt>.  The Release
 331 build requires considerably less space.</p>
 332
 333 <p>The LLVM suite <i>may</i> compile on other platforms, but it is not
 334 guaranteed to do so.  If compilation is successful, the LLVM utilities should be
 335 able to assemble, disassemble, analyze, and optimize LLVM bitcode.  Code
 336 generation should work as well, although the generated native code may not work
 337 on your platform.</p>
 338
 339 <p>The GCC front end is not very portable at the moment.  If you want to get it
 340 to work on another platform, you can download a copy of the source and <a
 341 href="GCCFEBuildInstrs.html">try to compile it</a> on your platform.</p>
 342
 343 </div>
 344
 345 <!-- ======================================================================= -->
 346 <div class="doc_subsection"><a name="software"><b>Software</b></a></div>
 347 <div class="doc_text">
 348   <p>Compiling LLVM requires that you have several software packages
 349   installed. The table below lists those required packages. The Package column
 350   is the usual name for the software package that LLVM depends on. The Version
 351   column provides "known to work" versions of the package. The Notes column
 352   describes how LLVM uses the package and provides other details.</p>
 353   <table summary="Packages required to compile LLVM">
 354     <tr><th>Package</th><th>Version</th><th>Notes</th></tr>
 355
 356     <tr>
 357       <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
 358       <td>3.79, 3.79.1</td>
 359       <td>Makefile/build processor</td>
 360     </tr>
 361
 362     <tr>
 363       <td><a href="http://gcc.gnu.org">GCC</a></td>
 364       <td>3.4.2</td>
 365       <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
 366     </tr>
 367
 368     <tr>
 369       <td><a href="http://www.gnu.org/software/texinfo">TeXinfo</a></td>
 370       <td>4.5</td>
 371       <td>For building the CFE</td>
 372     </tr>
 373
 374     <tr>
 375       <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
 376       <td>&ge;1.3</td>
 377       <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
 378     </tr>
 379
 380     <tr>
 381       <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
 382       <td>1.4.2</td>
 383       <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
 384     </tr>
 385
 386     <tr>
 387       <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
 388       <td>8.3, 8.4</td>
 389       <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
 390     </tr>
 391
 392     <tr>
 393       <td><a href="http://expect.nist.gov/">expect</a></td>
 394       <td>5.38.0</td>
 395       <td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
 396     </tr>
 397
 398     <tr>
 399       <td><a href="http://www.perl.com/download.csp">perl</a></td>
 400       <td>&ge;5.6.0</td>
 401       <td>Nightly tester, utilities</td>
 402     </tr>
 403
 404     <tr>
 405       <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
 406       <td>1.4</td>
 407       <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
 408     </tr>
 409
 410     <tr>
 411       <td><a href="http://www.gnu.org/software/autoconf">GNU Autoconf</a></td>
 412       <td>2.59</td>
 413       <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
 414     </tr>
 415
 416     <tr>
 417       <td><a href="http://www.gnu.org/software/automake">GNU Automake</a></td>
 418       <td>1.9.2</td>
 419       <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
 420     </tr>
 421
 422     <tr>
 423       <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
 424       <td>1.5.10</td>
 425       <td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
 426     </tr>
 427
 428   </table>
 429
 430   <p><b>Notes:</b></p>
 431   <div class="doc_notes">
 432   <ol>
 433     <li><a name="sf1">Only the C and C++ languages are needed so there's no
 434       need to build the other languages for LLVM's purposes.</a> See
 435       <a href="#brokengcc">below</a> for specific version info.</li>
 436     <li><a name="sf2">You only need Subversion if you intend to build from the
 437       latest LLVM sources. If you're working from a release distribution, you
 438       don't need Subversion.</a></li>
 439     <li><a name="sf3">Only needed if you want to run the automated test
 440       suite in the <tt>llvm/test</tt> directory.</a></li>
 441     <li><a name="sf4">If you want to make changes to the configure scripts,
 442       you will need GNU autoconf (2.59), and consequently, GNU M4 (version 1.4
 443       or higher). You will also need automake (1.9.2). We only use aclocal
 444       from that package.</a></li>
 445   </ol>
 446   </div>
 447
 448   <p>Additionally, your compilation host is expected to have the usual
 449   plethora of Unix utilities. Specifically:</p>
 450   <ul>
 451     <li><b>ar</b> - archive library builder</li>
 452     <li><b>bzip2*</b> - bzip2 command for distribution generation</li>
 453     <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
 454     <li><b>chmod</b> - change permissions on a file</li>
 455     <li><b>cat</b> - output concatenation utility</li>
 456     <li><b>cp</b> - copy files</li>
 457     <li><b>date</b> - print the current date/time </li>
 458     <li><b>echo</b> - print to standard output</li>
 459     <li><b>egrep</b> - extended regular expression search utility</li>
 460     <li><b>find</b> - find files/dirs in a file system</li>
 461     <li><b>grep</b> - regular expression search utility</li>
 462     <li><b>gzip*</b> - gzip command for distribution generation</li>
 463     <li><b>gunzip*</b> - gunzip command for distribution checking</li>
 464     <li><b>install</b> - install directories/files </li>
 465     <li><b>mkdir</b> - create a directory</li>
 466     <li><b>mv</b> - move (rename) files</li>
 467     <li><b>ranlib</b> - symbol table builder for archive libraries</li>
 468     <li><b>rm</b> - remove (delete) files and directories</li>
 469     <li><b>sed</b> - stream editor for transforming output</li>
 470     <li><b>sh</b> - Bourne shell for make build scripts</li>
 471     <li><b>tar</b> - tape archive for distribution generation</li>
 472     <li><b>test</b> - test things in file system</li>
 473     <li><b>unzip*</b> - unzip command for distribution checking</li>
 474     <li><b>zip*</b> - zip command for distribution generation</li>
 475   </ul>
 476 </div>
 477
 478 <!-- ======================================================================= -->
 479 <div class="doc_subsection">
 480   <a name="brokengcc">Broken versions of GCC and other tools</a>
 481 </div>
 482
 483 <div class="doc_text">
 484
 485 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
 486 bugs in the compiler.  In particular, several versions of GCC crash when trying
 487 to compile LLVM.  We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1
 488 successfully with them (however, see important notes below).  Other versions
 489 of GCC will probably work as well.  GCC versions listed
 490 here are known to not work.  If you are using one of these versions, please try
 491 to upgrade your GCC to something more recent.  If you run into a problem with a
 492 version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
 493 us know</a>.  Please use the "<tt>gcc -v</tt>" command to find out which version
 494 of GCC you are using.
 495 </p>
 496
 497 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
 498 problems in the STL that effectively prevent it from compiling LLVM.
 499 </p>
 500
 501 <p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
 502 a bogus template error.  This was fixed in later GCCs.</p>
 503
 504 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
 505 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
 506 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
 507
 508 <p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with
 509    Cygwin does not work.  Please <a href="GCCFEBuildInstrs.html#cygwin">upgrade
 510    to a newer version</a> if possible.</p>
 511 <p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
 512    possibly others) does not compile LLVM correctly (it appears that exception
 513    handling is broken in some cases).  Please download the FSF 3.3.3 or upgrade
 514    to a newer version of GCC.</p>
 515 <p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
 516    code generator, causing an infinite loop in the llvm-gcc build when built
 517    with optimizations enabled (i.e. a release build).</p>
 518 <p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
 519    code generator at -O3, as with 3.4.0.  However gcc 3.4.2 (unlike 3.4.0)
 520    correctly compiles LLVM at -O2.  A work around is to build release LLVM
 521    builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
 522 <p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
 523    miscompiles portions of LLVM</a>.</p>
 524 <p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
 525    when building with optimizations enabled.  It appears to work with
 526    "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
 527    build.</p>
 528 <p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
 529    miscompile LLVM.</p>
 530 <p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
 531    default with ENABLE_OPTIMIZED=1.  To work around this, build with
 532    "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
 533 <p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
 534       compiling some files.  At the time of this writing, GCC mainline (4.2)
 535       did not share the problem.</p>
 536 <p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
 537    miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
 538    code.  LLVM will appear to mostly work but will be buggy, e.g. failing
 539    portions of its testsuite.</p>
 540 <p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
 541 platforms compiling md5.c gets a mangled constant.</p>
 542 <p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
 543 to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
 544 about symbols remaining in the table on destruction.</p>
 545 <p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms
 546 as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
 547
 548 <p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
 549 long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
 550 defined in a discarded section. You can safely ignore these messages as they are
 551 erroneous and the linkage is correct.  These messages disappear using ld
 552 2.17.</p>
 553
 554 <p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
 555 href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
 556 causes huge link times (minutes instead of seconds) when building LLVM.  We
 557 recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
 558
 559 <p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained
 560 <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a>
 561 which causes intermittent failures when building LLVM with position independent
 562 code.  The symptom is an error about cyclic dependencies.  We recommend
 563 upgrading to a newer version of Gold.</p>
 564
 565 </div>
 566
 567
 568
 569 <!-- *********************************************************************** -->
 570 <div class="doc_section">
 571   <a name="starting"><b>Getting Started with LLVM</b></a>
 572 </div>
 573 <!-- *********************************************************************** -->
 574
 575 <div class="doc_text">
 576
 577 <p>The remainder of this guide is meant to get you up and running with
 578 LLVM and to give you some basic information about the LLVM environment.</p>
 579
 580 <p>The later sections of this guide describe the <a
 581 href="#layout">general layout</a> of the the LLVM source tree, a <a
 582 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
 583 href="#links">links</a> to find more information about LLVM or to get
 584 help via e-mail.</p>
 585 </div>
 586
 587 <!-- ======================================================================= -->
 588 <div class="doc_subsection">
 589   <a name="terminology">Terminology and Notation</a>
 590 </div>
 591
 592 <div class="doc_text">
 593
 594 <p>Throughout this manual, the following names are used to denote paths
 595 specific to the local system and working environment.  <i>These are not
 596 environment variables you need to set but just strings used in the rest
 597 of this document below</i>.  In any of the examples below, simply replace
 598 each of these names with the appropriate pathname on your local system.
 599 All these paths are absolute:</p>
 600
 601 <dl>
 602     <dt>SRC_ROOT
 603     <dd>
 604     This is the top level directory of the LLVM source tree.
 605     <br><br>
 606
 607     <dt>OBJ_ROOT
 608     <dd>
 609     This is the top level directory of the LLVM object tree (i.e. the
 610     tree where object files and compiled programs will be placed.  It
 611     can be the same as SRC_ROOT).
 612     <br><br>
 613
 614     <dt>LLVMGCCDIR
 615     <dd>
 616     This is where the LLVM GCC Front End is installed.
 617     <p>
 618     For the pre-built GCC front end binaries, the LLVMGCCDIR is
 619     <tt>llvm-gcc/<i>platform</i>/llvm-gcc</tt>.
 620 </dl>
 621
 622 </div>
 623
 624 <!-- ======================================================================= -->
 625 <div class="doc_subsection">
 626   <a name="environment">Setting Up Your Environment</a>
 627 </div>
 628
 629 <div class="doc_text">
 630
 631 <p>
 632 In order to compile and use LLVM, you may need to set some environment
 633 variables.
 634
 635 <dl>
 636   <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
 637   <dd>[Optional] This environment variable helps LLVM linking tools find the
 638   locations of your bitcode libraries. It is provided only as a
 639   convenience since you can specify the paths using the -L options of the
 640   tools and the C/C++ front-end will automatically use the bitcode files
 641   installed in its
 642   <tt>lib</tt> directory.</dd>
 643 </dl>
 644
 645 </div>
 646
 647 <!-- ======================================================================= -->
 648 <div class="doc_subsection">
 649   <a name="unpack">Unpacking the LLVM Archives</a>
 650 </div>
 651
 652 <div class="doc_text">
 653
 654 <p>
 655 If you have the LLVM distribution, you will need to unpack it before you
 656 can begin to compile it.  LLVM is distributed as a set of two files: the LLVM
 657 suite and the LLVM GCC front end compiled for your platform.  There is an
 658 additional test suite that is optional.  Each file is a TAR archive that is
 659 compressed with the gzip program.
 660 </p>
 661
 662 <p>The files are as follows, with <em>x.y</em> marking the version number:
 663 <dl>
 664   <dt><tt>llvm-x.y.tar.gz</tt></dt>
 665   <dd>Source release for the LLVM libraries and tools.<br></dd>
 666
 667   <dt><tt>llvm-test-x.y.tar.gz</tt></dt>
 668   <dd>Source release for the LLVM test suite.</dd>
 669
 670   <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt>
 671   <dd>Source release of the llvm-gcc-4.2 front end.  See README.LLVM in the root
 672       directory for build instructions.<br></dd>
 673
 674   <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt>
 675   <dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd>
 676
 677 </dl>
 678
 679 </div>
 680
 681 <!-- ======================================================================= -->
 682 <div class="doc_subsection">
 683   <a name="checkout">Checkout LLVM from Subversion</a>
 684 </div>
 685
 686 <div class="doc_text">
 687
 688 <p>If you have access to our Subversion repository, you can get a fresh copy of
 689 the entire source code.  All you need to do is check it out from Subvresion as
 690 follows:</p>
 691
 692 <ul>
 693   <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
 694   <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
 695   <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
 696     llvm</tt></li>
 697 </ul>
 698
 699
 700 <p>This will create an '<tt>llvm</tt>' directory in the current
 701 directory and fully populate it with the LLVM source code, Makefiles,
 702 test directories, and local copies of documentation files.</p>
 703
 704 <p>If you want to get a specific release (as opposed to the most recent
 705 revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
 706 '<tt>trunk</tt>'). The following releases are located in the following
 707 subdirectories of the '<tt>tags</tt>' directory:</p>
 708
 709 <ul>
 710 <li>Release 2.4: <b>RELEASE_24</b></li>
 711 <li>Release 2.3: <b>RELEASE_23</b></li>
 712 <li>Release 2.2: <b>RELEASE_22</b></li>
 713 <li>Release 2.1: <b>RELEASE_21</b></li>
 714 <li>Release 2.0: <b>RELEASE_20</b></li>
 715 <li>Release 1.9: <b>RELEASE_19</b></li>
 716 <li>Release 1.8: <b>RELEASE_18</b></li>
 717 <li>Release 1.7: <b>RELEASE_17</b></li>
 718 <li>Release 1.6: <b>RELEASE_16</b></li>
 719 <li>Release 1.5: <b>RELEASE_15</b></li>
 720 <li>Release 1.4: <b>RELEASE_14</b></li>
 721 <li>Release 1.3: <b>RELEASE_13</b></li>
 722 <li>Release 1.2: <b>RELEASE_12</b></li>
 723 <li>Release 1.1: <b>RELEASE_11</b></li>
 724 <li>Release 1.0: <b>RELEASE_1</b></li>
 725 </ul>
 726
 727 <p>If you would like to get the LLVM test suite (a separate package as of 1.4),
 728 you get it from the Subversion repository:</p>
 729
 730 <div class="doc_code">
 731 <pre>
 732 % cd llvm/projects
 733 % svn co http://llvm.org/svn/llvm-project/test-suite/trunk llvm-test
 734 </pre>
 735 </div>
 736
 737 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
 738 configured by the LLVM configure script as well as automatically updated when
 739 you run <tt>svn update</tt>.</p>
 740
 741 <p>If you would like to get the GCC front end source code, you can also get it
 742 and build it yourself.  Please follow <a href="GCCFEBuildInstrs.html">these
 743 instructions</a> to successfully get and build the LLVM GCC front-end.</p>
 744
 745 </div>
 746
 747 <!-- ======================================================================= -->
 748 <div class="doc_subsection">
 749   <a name="installcf">Install the GCC Front End</a>
 750 </div>
 751
 752 <div class="doc_text">
 753
 754 <p>Before configuring and compiling the LLVM suite, you can optionally extract the
 755 LLVM GCC front end from the binary distribution.  It is used for running the
 756 llvm-test testsuite and for compiling C/C++ programs.  Note that you can optionally
 757 <a href="GCCFEBuildInstrs.html">build llvm-gcc yourself</a> after building the
 758 main LLVM repository.</p>
 759
 760 <p>To install the GCC front end, do the following:</p>
 761
 762 <ol>
 763   <li><tt>cd <i>where-you-want-the-front-end-to-live</i></tt></li>
 764   <li><tt>gunzip --stdout llvm-gcc-4.2-<i>version</i>-<i>platform</i>.tar.gz | tar -xvf
 765       -</tt></li>
 766 </ol>
 767
 768 <p>Once the binary is uncompressed, you should add a symlink for llvm-gcc and
 769 llvm-g++ to some directory in your path.  When you configure LLVM, it will
 770 automatically detect llvm-gcc's presence (if it is in your path) enabling its
 771 use in llvm-test.  Note that you can always build or install llvm-gcc at any
 772 pointer after building the main LLVM repository: just reconfigure llvm and
 773 llvm-test will pick it up.
 774 </p>
 775
 776 <p>The binary versions of the GCC front end may not suit all of your needs.  For
 777 example, the binary distribution may include an old version of a system header
 778 file, not "fix" a header file that needs to be fixed for GCC, or it may be
 779 linked with libraries not available on your system.</p>
 780
 781 <p>In cases like these, you may want to try <a
 782 href="GCCFEBuildInstrs.html">building the GCC front end from source.</a> This is
 783 much easier now than it was in the past.</p>
 784
 785 </div>
 786
 787 <!-- ======================================================================= -->
 788 <div class="doc_subsection">
 789   <a name="config">Local LLVM Configuration</a>
 790 </div>
 791
 792 <div class="doc_text">
 793
 794   <p>Once checked out from the Subversion repository, the LLVM suite source
 795   code must be
 796 configured via the <tt>configure</tt> script.  This script sets variables in the
 797 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
 798 <tt>llvm/include/Config/config.h</tt>.  It also populates <i>OBJ_ROOT</i> with
 799 the Makefiles needed to begin building LLVM.</p>
 800
 801 <p>The following environment variables are used by the <tt>configure</tt>
 802 script to configure the build system:</p>
 803
 804 <table summary="LLVM configure script environment variables">
 805   <tr><th>Variable</th><th>Purpose</th></tr>
 806   <tr>
 807     <td>CC</td>
 808     <td>Tells <tt>configure</tt> which C compiler to use.  By default,
 809         <tt>configure</tt> will look for the first GCC C compiler in
 810         <tt>PATH</tt>.  Use this variable to override
 811         <tt>configure</tt>'s default behavior.</td>
 812   </tr>
 813   <tr>
 814     <td>CXX</td>
 815     <td>Tells <tt>configure</tt> which C++ compiler to use.  By default,
 816        <tt>configure</tt> will look for the first GCC C++ compiler in
 817        <tt>PATH</tt>.  Use this variable to override
 818        <tt>configure</tt>'s default behavior.</td>
 819   </tr>
 820 </table>
 821
 822 <p>The following options can be used to set or enable LLVM specific options:</p>
 823
 824 <dl>
 825   <dt><i>--with-llvmgccdir</i></dt>
 826   <dd>Path to the LLVM C/C++ FrontEnd to be used with this LLVM configuration.
 827   The value of this option should specify the full pathname of the C/C++ Front
 828   End to be used. If this option is not provided, the PATH will be searched for
 829   a program named <i>llvm-gcc</i> and the C/C++ FrontEnd install directory will
 830   be inferred from the path found. If the option is not given, and no llvm-gcc
 831   can be found in the path then a warning will be produced by
 832   <tt>configure</tt> indicating this situation. LLVM may still be built with
 833   the <tt>tools-only</tt> target but attempting to build the runtime libraries
 834   will fail as these libraries require llvm-gcc and llvm-g++. See
 835   <a href="#installcf">Install the GCC Front End</a> for details on installing
 836   the C/C++ Front End. See
 837   <a href="GCCFEBuildInstrs.html">Bootstrapping the LLVM C/C++ Front-End</a>
 838   for details on building the C/C++ Front End.</dd>
 839   <dt><i>--with-tclinclude</i></dt>
 840   <dd>Path to the tcl include directory under which <tt>tclsh</tt> can be
 841   found. Use this if you have multiple tcl installations on your machine and you
 842   want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the
 843   dejagnu based test suite in <tt>llvm/test</tt>. If you don't specify this
 844   option, the LLVM configure script will search for the tcl 8.4 and 8.3
 845   releases.
 846   <br><br>
 847   </dd>
 848   <dt><i>--enable-optimized</i></dt>
 849   <dd>
 850     Enables optimized compilation by default (debugging symbols are removed
 851     and GCC optimization flags are enabled).  The default is to use an
 852     unoptimized build (also known as a debug build).
 853     <br><br>
 854   </dd>
 855   <dt><i>--enable-debug-runtime</i></dt>
 856   <dd>
 857     Enables debug symbols in the runtime libraries. The default is to strip
 858     debug symbols from the runtime libraries.
 859   </dd>
 860   <dt><i>--enable-jit</i></dt>
 861   <dd>
 862     Compile the Just In Time (JIT) compiler functionality.  This is not
 863     available
 864     on all platforms.  The default is dependent on platform, so it is best
 865     to explicitly enable it if you want it.
 866     <br><br>
 867   </dd>
 868   <dt><i>--enable-targets=</i><tt>target-option</tt></dt>
 869   <dd>Controls which targets will be built and linked into llc. The default
 870   value for <tt>target_options</tt> is "all" which builds and links all
 871   available targets.  The value "host-only" can be specified to build only a
 872   native compiler (no cross-compiler targets available). The "native" target is
 873   selected as the target of the build host. You can also specify a comma
 874   separated list of target names that you want available in llc. The target
 875   names use all lower case. The current set of targets is: <br>
 876   <tt>alpha, ia64, powerpc, skeleton, sparc, x86</tt>.
 877   <br><br></dd>
 878   <dt><i>--enable-doxygen</i></dt>
 879   <dd>Look for the doxygen program and enable construction of doxygen based
 880   documentation from the source code. This is disabled by default because
 881   generating the documentation can take a long time and producess 100s of
 882   megabytes of output.</dd>
 883   <dt><i>--with-udis86</i></dt>
 884   <dd>LLVM can use external disassembler library for various purposes (now it's
 885   used only for examining code produced by JIT). This option will enable usage
 886   of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
 887   bits) disassembler library.</dd>
 888 </dl>
 889
 890 <p>To configure LLVM, follow these steps:</p>
 891
 892 <ol>
 893     <li><p>Change directory into the object root directory:</p>
 894
 895     <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
 896
 897     <li><p>Run the <tt>configure</tt> script located in the LLVM source
 898     tree:</p>
 899
 900     <div class="doc_code">
 901     <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
 902     </div></li>
 903 </ol>
 904
 905 </div>
 906
 907 <!-- ======================================================================= -->
 908 <div class="doc_subsection">
 909   <a name="compile">Compiling the LLVM Suite Source Code</a>
 910 </div>
 911
 912 <div class="doc_text">
 913
 914 <p>Once you have configured LLVM, you can build it.  There are three types of
 915 builds:</p>
 916
 917 <dl>
 918     <dt>Debug Builds
 919     <dd>
 920     These builds are the default when one types <tt>gmake</tt> (unless the
 921     <tt>--enable-optimized</tt> option was used during configuration).  The
 922     build system will compile the tools and libraries with debugging
 923     information.
 924     <br><br>
 925
 926     <dt>Release (Optimized) Builds
 927     <dd>
 928     These builds are enabled with the <tt>--enable-optimized</tt> option to
 929     <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
 930     <tt>gmake</tt> command line.  For these builds, the build system will
 931     compile the tools and libraries with GCC optimizations enabled and strip
 932     debugging information from the libraries and executables it generates.
 933     <br><br>
 934
 935     <dt>Profile Builds
 936     <dd>
 937     These builds are for use with profiling.  They compile profiling
 938     information into the code for use with programs like <tt>gprof</tt>.
 939     Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
 940     on the <tt>gmake</tt> command line.
 941 </dl>
 942
 943 <p>Once you have LLVM configured, you can build it by entering the
 944 <i>OBJ_ROOT</i> directory and issuing the following command:</p>
 945
 946 <div class="doc_code"><pre>% gmake</pre></div>
 947
 948 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
 949 are using a version of GCC that is known not to compile LLVM.</p>
 950
 951 <p>
 952 If you have multiple processors in your machine, you may wish to use some of
 953 the parallel build options provided by GNU Make.  For example, you could use the
 954 command:</p>
 955
 956 <div class="doc_code"><pre>% gmake -j2</pre></div>
 957
 958 <p>There are several special targets which are useful when working with the LLVM
 959 source code:</p>
 960
 961 <dl>
 962   <dt><tt>gmake clean</tt>
 963   <dd>
 964   Removes all files generated by the build.  This includes object files,
 965   generated C/C++ files, libraries, and executables.
 966   <br><br>
 967
 968   <dt><tt>gmake dist-clean</tt>
 969   <dd>
 970   Removes everything that <tt>gmake clean</tt> does, but also removes files
 971   generated by <tt>configure</tt>.  It attempts to return the source tree to the
 972   original state in which it was shipped.
 973   <br><br>
 974
 975   <dt><tt>gmake install</tt>
 976   <dd>
 977   Installs LLVM header files, libraries, tools, and documentation in a
 978   hierarchy
 979   under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
 980   defaults to <tt>/usr/local</tt>.
 981   <br><br>
 982
 983   <dt><tt>gmake -C runtime install-bytecode</tt>
 984   <dd>
 985   Assuming you built LLVM into $OBJDIR, when this command is run, it will
 986   install bitcode libraries into the GCC front end's bitcode library
 987   directory.  If you need to update your bitcode libraries,
 988   this is the target to use once you've built them.
 989   <br><br>
 990 </dl>
 991
 992 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
 993 details on these <tt>make</tt> targets and descriptions of other targets
 994 available.</p>
 995
 996 <p>It is also possible to override default values from <tt>configure</tt> by
 997 declaring variables on the command line.  The following are some examples:</p>
 998
 999 <dl>
1000   <dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
1001   <dd>
1002   Perform a Release (Optimized) build.
1003   <br><br>
1004
1005   <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
1006   <dd>
1007   Perform a Release (Optimized) build without assertions enabled.
1008   <br><br>
1009
1010   <dt><tt>gmake ENABLE_PROFILING=1</tt>
1011   <dd>
1012   Perform a Profiling build.
1013   <br><br>
1014
1015   <dt><tt>gmake VERBOSE=1</tt>
1016   <dd>
1017   Print what <tt>gmake</tt> is doing on standard output.
1018   <br><br>
1019
1020   <dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
1021   <dd>Ask each tool invoked by the makefiles to print out what it is doing on
1022   the standard output. This also implies <tt>VERBOSE=1</tt>.
1023   <br><br></dd>
1024 </dl>
1025
1026 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
1027 it and any subdirectories that it contains.  Entering any directory inside the
1028 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
1029 that directory that is out of date.</p>
1030
1031 </div>
1032
1033 <!-- ======================================================================= -->
1034 <div class="doc_subsection">
1035   <a name="cross-compile">Cross-Compiling LLVM</a>
1036 </div>
1037
1038 <div class="doc_text">
1039   <p>It is possible to cross-compile LLVM. That is, you can create LLVM
1040   executables and libraries for a platform different than the one one which you
1041   are compiling.  To do this, a few additional steps are
1042   required. <sup><a href="#ccn_1">1</a></sup> To cross-compile LLVM, use
1043   these instructions:</p>
1044   <ol>
1045     <li>Configure and build LLVM as a native compiler. You will need
1046     just <tt>TableGen</tt> from that build.
1047       <ul>
1048         <li>If you have <tt>$LLVM_OBJ_ROOT=$LLVM_SRC_ROOT</tt> just execute
1049           <tt>make -C utils/TableGen</tt> after configuring.</li>
1050         <li>Otherwise you will need to monitor building process and terminate
1051           it just after <tt>TableGen</tt> was built.</li>
1052       </ul>
1053     </li>
1054     <li>Copy the TableGen binary to somewhere safe (out of your build tree).
1055     </li>
1056     <li>Configure LLVM to build with a cross-compiler. To do this, supply the
1057     configure script with <tt>--build</tt> and <tt>--host</tt> options that
1058     are different. The values of these options must be legal target triples
1059     that your GCC compiler supports.</li>
1060     <li>Put the saved <tt>TableGen</tt> executable into the
1061     into <tt>$LLVM_OBJ_ROOT/{BUILD_TYPE}/bin</tt> directory (e.g. into
1062     <tt>.../Release/bin</tt> for a Release build).</li>
1063     <li>Build LLVM  as usual.</li>
1064   </ol>
1065   <p>The result of such a build will produce executables that are not executable
1066   on your build host (--build option) but can be executed on your compile host
1067   (--host option).</p>
1068   <p><b>Notes:</b></p>
1069   <div class="doc_notes">
1070     <ol>
1071       <li><a name="ccn_1">Cross-compiling</a> was tested only with Linux as
1072       build platform and Windows as host using mingw32 cross-compiler. Other
1073       combinations have not been tested.</li>
1074     </ol>
1075   </div>
1076 </div>
1077
1078 <!-- ======================================================================= -->
1079 <div class="doc_subsection">
1080   <a name="objfiles">The Location of LLVM Object Files</a>
1081 </div>
1082
1083 <div class="doc_text">
1084
1085 <p>The LLVM build system is capable of sharing a single LLVM source tree among
1086 several LLVM builds.  Hence, it is possible to build LLVM for several different
1087 platforms or configurations using the same source tree.</p>
1088
1089 <p>This is accomplished in the typical autoconf manner:</p>
1090
1091 <ul>
1092   <li><p>Change directory to where the LLVM object files should live:</p>
1093
1094       <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
1095
1096   <li><p>Run the <tt>configure</tt> script found in the LLVM source
1097       directory:</p>
1098
1099       <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
1100 </ul>
1101
1102 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
1103 named after the build type:</p>
1104
1105 <dl>
1106   <dt>Debug Builds
1107   <dd>
1108   <dl>
1109     <dt>Tools
1110     <dd><tt><i>OBJ_ROOT</i>/Debug/bin</tt>
1111     <dt>Libraries
1112     <dd><tt><i>OBJ_ROOT</i>/Debug/lib</tt>
1113   </dl>
1114   <br><br>
1115
1116   <dt>Release Builds
1117   <dd>
1118   <dl>
1119     <dt>Tools
1120     <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
1121     <dt>Libraries
1122     <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
1123   </dl>
1124   <br><br>
1125
1126   <dt>Profile Builds
1127   <dd>
1128   <dl>
1129     <dt>Tools
1130     <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
1131     <dt>Libraries
1132     <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
1133   </dl>
1134 </dl>
1135
1136 </div>
1137
1138 <!-- ======================================================================= -->
1139 <div class="doc_subsection">
1140   <a name="optionalconfig">Optional Configuration Items</a>
1141 </div>
1142
1143 <div class="doc_text">
1144
1145 <p>
1146 If you're running on a Linux system that supports the "<a
1147 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
1148 module, and you have root access on the system, you can set your system up to
1149 execute LLVM bitcode files directly. To do this, use commands like this (the
1150 first command may not be required if you are already using the module):</p>
1151
1152 <div class="doc_code">
1153 <pre>
1154 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
1155 $ echo ':llvm:M::llvm::/path/to/lli:' &gt; /proc/sys/fs/binfmt_misc/register
1156 $ chmod u+x hello.bc   (if needed)
1157 $ ./hello.bc
1158 </pre>
1159 </div>
1160
1161 <p>
1162 This allows you to execute LLVM bitcode files directly.  Thanks to Jack
1163 Cummings for pointing this out!
1164 </p>
1165
1166 </div>
1167
1168
1169 <!-- *********************************************************************** -->
1170 <div class="doc_section">
1171   <a name="layout"><b>Program Layout</b></a>
1172 </div>
1173 <!-- *********************************************************************** -->
1174
1175 <div class="doc_text">
1176
1177 <p>One useful source of information about the LLVM source base is the LLVM <a
1178 href="http://www.doxygen.org">doxygen</a> documentation available at <tt><a
1179 href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
1180 The following is a brief introduction to code layout:</p>
1181
1182 </div>
1183
1184 <!-- ======================================================================= -->
1185 <div class="doc_subsection"><a name="examples"><tt>llvm/examples</tt></a></div>
1186 <div class="doc_text">
1187   <p>This directory contains some simple examples of how to use the LLVM IR and
1188   JIT.</p>
1189 </div>
1190
1191 <!-- ======================================================================= -->
1192 <div class="doc_subsection"><a name="include"><tt>llvm/include</tt></a></div>
1193 <div class="doc_text">
1194
1195 <p>This directory contains public header files exported from the LLVM
1196 library. The three main subdirectories of this directory are:</p>
1197
1198 <dl>
1199   <dt><tt><b>llvm/include/llvm</b></tt></dt>
1200   <dd>This directory contains all of the LLVM specific header files.  This
1201   directory also has subdirectories for different portions of LLVM:
1202   <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
1203   etc...</dd>
1204
1205   <dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
1206   <dd>This directory contains generic support libraries that are provided with
1207   LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
1208   and a Command Line option processing library store their header files here.
1209   </dd>
1210
1211   <dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
1212   <dd>This directory contains header files configured by the <tt>configure</tt>
1213   script.  They wrap "standard" UNIX and C header files.  Source code can
1214   include these header files which automatically take care of the conditional
1215   #includes that the <tt>configure</tt> script generates.</dd>
1216 </dl>
1217 </div>
1218
1219 <!-- ======================================================================= -->
1220 <div class="doc_subsection"><a name="lib"><tt>llvm/lib</tt></a></div>
1221 <div class="doc_text">
1222
1223 <p>This directory contains most of the source files of the LLVM system. In LLVM,
1224 almost all code exists in libraries, making it very easy to share code among the
1225 different <a href="#tools">tools</a>.</p>
1226
1227 <dl>
1228   <dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
1229   <dd> This directory holds the core LLVM source files that implement core
1230   classes like Instruction and BasicBlock.</dd>
1231
1232   <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
1233   <dd>This directory holds the source code for the LLVM assembly language parser
1234   library.</dd>
1235
1236   <dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
1237   <dd>This directory holds code for reading and write LLVM bitcode.</dd>
1238
1239   <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
1240   different program analyses, such as Dominator Information, Call Graphs,
1241   Induction Variables, Interval Identification, Natural Loop Identification,
1242   etc.</dd>
1243
1244   <dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
1245   <dd> This directory contains the source code for the LLVM to LLVM program
1246   transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
1247   Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
1248   Elimination, and many others.</dd>
1249
1250   <dt><tt><b>llvm/lib/Target/</b></tt></dt>
1251   <dd> This directory contains files that describe various target architectures
1252   for code generation.  For example, the <tt>llvm/lib/Target/X86</tt>
1253   directory holds the X86 machine description while
1254   <tt>llvm/lib/Target/CBackend</tt> implements the LLVM-to-C converter.</dd>
1255
1256   <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
1257   <dd> This directory contains the major parts of the code generator: Instruction
1258   Selector, Instruction Scheduling, and Register Allocation.</dd>
1259
1260   <dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
1261   <dd> This directory contains the source level debugger library that makes
1262   it possible to instrument LLVM programs so that a debugger could identify
1263   source code locations at which the program is executing.</dd>
1264
1265   <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
1266   <dd> This directory contains libraries for executing LLVM bitcode directly
1267   at runtime in both interpreted and JIT compiled fashions.</dd>
1268
1269   <dt><tt><b>llvm/lib/Support/</b></tt></dt>
1270   <dd> This directory contains the source code that corresponds to the header
1271   files located in <tt>llvm/include/Support/</tt>.</dd>
1272
1273   <dt><tt><b>llvm/lib/System/</b></tt></dt>
1274   <dd>This directory contains the operating system abstraction layer that
1275   shields LLVM from platform-specific coding.</dd>
1276 </dl>
1277
1278 </div>
1279
1280 <!-- ======================================================================= -->
1281 <div class="doc_subsection"><a name="projects"><tt>llvm/projects</tt></a></div>
1282 <div class="doc_text">
1283   <p>This directory contains projects that are not strictly part of LLVM but are
1284   shipped with LLVM. This is also the directory where you should create your own
1285   LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
1286   to set up your own project.</p>
1287 </div>
1288
1289 <!-- ======================================================================= -->
1290 <div class="doc_subsection"><a name="runtime"><tt>llvm/runtime</tt></a></div>
1291 <div class="doc_text">
1292
1293 <p>This directory contains libraries which are compiled into LLVM bitcode and
1294 used when linking programs with the GCC front end.  Most of these libraries are
1295 skeleton versions of real libraries; for example, libc is a stripped down
1296 version of glibc.</p>
1297
1298 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
1299 end to compile.</p>
1300
1301 </div>
1302
1303 <!-- ======================================================================= -->
1304 <div class="doc_subsection"><a name="test"><tt>llvm/test</tt></a></div>
1305 <div class="doc_text">
1306   <p>This directory contains feature and regression tests and other basic sanity
1307   checks on the LLVM infrastructure. These are intended to run quickly and cover
1308   a lot of territory without being exhaustive.</p>
1309 </div>
1310
1311 <!-- ======================================================================= -->
1312 <div class="doc_subsection"><a name="llvmtest"><tt>test-suite</tt></a></div>
1313 <div class="doc_text">
1314   <p>This is not a directory in the normal llvm module; it is a separate
1315   Subversion
1316   module that must be checked out (usually to <tt>projects/test-suite</tt>).
1317   This
1318   module contains a comprehensive correctness, performance, and benchmarking
1319   test
1320   suite for LLVM. It is a separate Subversion module because not every LLVM
1321   user is
1322   interested in downloading or building such a comprehensive test suite. For
1323   further details on this test suite, please see the
1324   <a href="TestingGuide.html">Testing Guide</a> document.</p>
1325 </div>
1326
1327 <!-- ======================================================================= -->
1328 <div class="doc_subsection"><a name="tools"><tt>llvm/tools</tt></a></div>
1329 <div class="doc_text">
1330
1331 <p>The <b>tools</b> directory contains the executables built out of the
1332 libraries above, which form the main part of the user interface.  You can
1333 always get help for a tool by typing <tt>tool_name --help</tt>.  The
1334 following is a brief introduction to the most important tools.  More detailed
1335 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
1336
1337 <dl>
1338
1339   <dt><tt><b>bugpoint</b></tt></dt>
1340   <dd><tt>bugpoint</tt> is used to debug
1341   optimization passes or code generation backends by narrowing down the
1342   given test case to the minimum number of passes and/or instructions that
1343   still cause a problem, whether it is a crash or miscompilation. See <a
1344   href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
1345   on using <tt>bugpoint</tt>.</dd>
1346
1347   <dt><tt><b>llvmc</b></tt></dt>
1348   <dd>The LLVM Compiler Driver. This program can
1349   be configured to utilize both LLVM and non-LLVM compilation tools to enable
1350   pre-processing, translation, optimization, assembly, and linking of programs
1351   all from one command line. <tt>llvmc</tt> also takes care of processing the
1352   dependent libraries found in bitcode. This reduces the need to get the
1353   traditional <tt>-l&lt;name&gt;</tt> options right on the command line. Please
1354   note that this tool, while functional, is still experimental and not feature
1355   complete.</dd>
1356
1357   <dt><tt><b>llvm-ar</b></tt></dt>
1358   <dd>The archiver produces an archive containing
1359   the given LLVM bitcode files, optionally with an index for faster
1360   lookup.</dd>
1361
1362   <dt><tt><b>llvm-as</b></tt></dt>
1363   <dd>The assembler transforms the human readable LLVM assembly to LLVM
1364   bitcode.</dd>
1365
1366   <dt><tt><b>llvm-dis</b></tt></dt>
1367   <dd>The disassembler transforms the LLVM bitcode to human readable
1368   LLVM assembly.</dd>
1369
1370   <dt><tt><b>llvm-ld</b></tt></dt>
1371   <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM.
1372   This is the linker invoked by <tt>llvmc</tt>. It performsn standard link time
1373   optimizations and allows optimization modules to be loaded and run so that
1374   language specific optimizations can be applied at link time.</dd>
1375
1376   <dt><tt><b>llvm-link</b></tt></dt>
1377   <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
1378   a single program.</dd>
1379
1380   <dt><tt><b>lli</b></tt></dt>
1381   <dd><tt>lli</tt> is the LLVM interpreter, which
1382   can directly execute LLVM bitcode (although very slowly...). For architectures
1383   that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
1384   will function as a Just-In-Time compiler (if the functionality was compiled
1385   in), and will execute the code <i>much</i> faster than the interpreter.</dd>
1386
1387   <dt><tt><b>llc</b></tt></dt>
1388   <dd> <tt>llc</tt> is the LLVM backend compiler, which
1389   translates LLVM bitcode to a native code assembly file or to C code (with
1390   the -march=c option).</dd>
1391
1392   <dt><tt><b>llvm-gcc</b></tt></dt>
1393   <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
1394   use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
1395   bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
1396   usual machine code output.  It works just like any other GCC compiler,
1397   taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
1398   Additionally, the the source code for <tt>llvm-gcc</tt> is available as a
1399   separate Subversion module.</dd>
1400
1401   <dt><tt><b>opt</b></tt></dt>
1402   <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
1403   transformations (which are specified on the command line), and then outputs
1404   the resultant bitcode.  The '<tt>opt --help</tt>' command is a good way to
1405   get a list of the program transformations available in LLVM.<br>
1406   <dd><tt>opt</tt> can also be used to run a specific analysis on an input
1407   LLVM bitcode file and print out the results.  It is primarily useful for
1408   debugging analyses, or familiarizing yourself with what an analysis does.</dd>
1409 </dl>
1410 </div>
1411
1412 <!-- ======================================================================= -->
1413 <div class="doc_subsection"><a name="utils"><tt>llvm/utils</tt></a></div>
1414 <div class="doc_text">
1415
1416 <p>This directory contains utilities for working with LLVM source code, and some
1417 of the utilities are actually required as part of the build process because they
1418 are code generators for parts of LLVM infrastructure.</p>
1419
1420 <dl>
1421   <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
1422   that finds differences between code that LLC generates and code that LLI
1423   generates. This is a useful tool if you are debugging one of them,
1424   assuming that the other generates correct output. For the full user
1425   manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
1426
1427   <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
1428   syntax-highlighting files which will work with Emacs and XEmacs editors,
1429   providing syntax highlighting support for LLVM assembly files and TableGen
1430   description files. For information on how to use the syntax files, consult
1431   the <tt>README</tt> file in that directory.<br><br>
1432
1433   <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
1434   and outputs all non-generated source files, which is useful if one wishes
1435   to do a lot of development across directories and does not want to
1436   individually find each file. One way to use it is to run, for example:
1437   <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
1438   tree.<br><br>
1439
1440   <dt><tt><b>llvmgrep</b></tt></dt>
1441   <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
1442   passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
1443   line. This is a very efficient way of searching the source base for a
1444   particular regular expression.</dd>
1445
1446   <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
1447   files in the current directory and then compiles and links the tool that
1448   is the first argument. For example, assuming you are in the directory
1449   <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
1450   simply running <tt>makellvm llc</tt> will make a build of the current
1451   directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
1452   causing a re-linking of LLC.<br><br>
1453
1454   <dt><tt><b>NewNightlyTest.pl</b></tt> and
1455   <tt><b>NightlyTestTemplate.html</b></tt> <dd>These files are used in a
1456   cron script to generate nightly status reports of the functionality of
1457   tools, and the results can be seen by following the appropriate link on
1458   the <a href="http://llvm.org/">LLVM homepage</a>.<br><br>
1459
1460   <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
1461   the tool used to generate register descriptions, instruction set
1462   descriptions, and even assemblers from common TableGen description
1463   files.<br><br>
1464
1465   <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
1466   syntax-highlighting files which will work with the VIM editor, providing
1467   syntax highlighting support for LLVM assembly files and TableGen
1468   description files. For information on how to use the syntax files, consult
1469   the <tt>README</tt> file in that directory.<br><br>
1470
1471 </dl>
1472
1473 </div>
1474
1475 <!-- ======================================================================= -->
1476 <div class="doc_subsection"><a name="win32"><tt>llvm/win32</tt></a></div>
1477 <div class="doc_text">
1478   <p>This directory contains build scripts and project files for use with
1479   Visual C++. This allows developers on Windows to build LLVM without the need
1480   for Cygwin. The contents of this directory should be considered experimental
1481   at this time.
1482   </p>
1483 </div>
1484 <!-- *********************************************************************** -->
1485 <div class="doc_section">
1486   <a name="tutorial">An Example Using the LLVM Tool Chain</a>
1487 </div>
1488 <!-- *********************************************************************** -->
1489
1490 <div class="doc_text">
1491 <p>This section gives an example of using LLVM.  llvm-gcc3 is now obsolete,
1492 so we only include instructiosn for llvm-gcc4.
1493 </p>
1494
1495 <p><b>Note:</b> The <i>gcc4</i> frontend's invocation is <b><i>considerably different</i></b>
1496 from the previous <i>gcc3</i> frontend. In particular, the <i>gcc4</i> frontend <b><i>does not</i></b>
1497 create bitcode by default: <i>gcc4</i> produces native code. As the example below illustrates,
1498 the '--emit-llvm' flag is needed to produce LLVM bitcode output. For <i>makefiles</i> and
1499 <i>configure</i> scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
1500 output.</p>
1501 </div>
1502
1503 <!-- ======================================================================= -->
1504 <div class="doc_subsection"><a name="tutorial4">Example with llvm-gcc4</a></div>
1505
1506 <div class="doc_text">
1507
1508 <ol>
1509   <li><p>First, create a simple C file, name it 'hello.c':</p>
1510
1511 <div class="doc_code">
1512 <pre>
1513 #include &lt;stdio.h&gt;
1514
1515 int main() {
1516   printf("hello world\n");
1517   return 0;
1518 }
1519 </pre></div></li>
1520
1521   <li><p>Next, compile the C file into a native executable:</p>
1522
1523       <div class="doc_code"><pre>% llvm-gcc hello.c -o hello</pre></div>
1524
1525       <p>Note that llvm-gcc works just like GCC by default.  The standard -S and
1526         -c arguments work as usual (producing a native .s or .o file,
1527         respectively).</p></li>
1528
1529   <li><p>Next, compile the C file into a LLVM bitcode file:</p>
1530
1531       <div class="doc_code">
1532       <pre>% llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
1533
1534       <p>The -emit-llvm option can be used with the -S or -c options to emit an
1535          LLVM ".ll" or ".bc" file (respectively) for the code.  This allows you
1536          to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
1537          the bitcode file.</p>
1538
1539       <p>Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
1540          </p></li>
1541
1542   <li><p>Run the program in both forms. To run the program, use:</p>
1543
1544       <div class="doc_code"><pre>% ./hello</pre></div>
1545
1546       <p>and</p>
1547
1548       <div class="doc_code"><pre>% lli hello.bc</pre></div>
1549
1550       <p>The second examples shows how to invoke the LLVM JIT, <a
1551        href="CommandGuide/html/lli.html">lli</a>.</p></li>
1552
1553   <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
1554       code:</p>
1555
1556 <div class="doc_code">
1557 <pre>llvm-dis &lt; hello.bc | less</pre>
1558 </div></li>
1559
1560   <li><p>Compile the program to native assembly using the LLC code
1561       generator:</p>
1562
1563       <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
1564
1565   <li><p>Assemble the native assembly language file into a program:</p>
1566
1567 <div class="doc_code">
1568 <pre>
1569 <b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
1570
1571 <b>Others:</b>  % gcc hello.s -o hello.native
1572 </pre>
1573 </div></li>
1574
1575   <li><p>Execute the native code program:</p>
1576
1577       <div class="doc_code"><pre>% ./hello.native</pre></div>
1578
1579       <p>Note that using llvm-gcc to compile directly to native code (i.e. when
1580          the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
1581         </li>
1582
1583 </ol>
1584
1585 </div>
1586
1587
1588 <!-- *********************************************************************** -->
1589 <div class="doc_section">
1590   <a name="problems">Common Problems</a>
1591 </div>
1592 <!-- *********************************************************************** -->
1593
1594 <div class="doc_text">
1595
1596 <p>If you are having problems building or using LLVM, or if you have any other
1597 general questions about LLVM, please consult the <a href="FAQ.html">Frequently
1598 Asked Questions</a> page.</p>
1599
1600 </div>
1601
1602 <!-- *********************************************************************** -->
1603 <div class="doc_section">
1604   <a name="links">Links</a>
1605 </div>
1606 <!-- *********************************************************************** -->
1607
1608 <div class="doc_text">
1609
1610 <p>This document is just an <b>introduction</b> on how to use LLVM to do
1611 some simple things... there are many more interesting and complicated things
1612 that you can do that aren't documented here (but we'll gladly accept a patch
1613 if you want to write something up!).  For more information about LLVM, check
1614 out:</p>
1615
1616 <ul>
1617   <li><a href="http://llvm.org/">LLVM homepage</a></li>
1618   <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
1619   <li><a href="http://llvm.org/docs/Projects.html">Starting a Project
1620   that Uses LLVM</a></li>
1621 </ul>
1622
1623 </div>
1624
1625 <!-- *********************************************************************** -->
1626
1627 <hr>
1628 <address>
1629   <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
1630   src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
1631   <a href="http://validator.w3.org/check/referer"><img
1632   src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
1633
1634   <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1635   <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
1636   <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
1637   Last modified: $Date$
1638 </address>
1639 </body>
1640 </html>