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 <h1> 12 Getting Started with the LLVM System 13 </h1> 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="#git_mirror">LLVM GIT mirror</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="#test-suite"><tt>test-suite</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 </ol></li> 51 52 <li><a href="#tutorial">An Example Using the LLVM Tool Chain</a> 53 <ol> 54 <li><a href="#tutorial4">Example with Clang</a></li> 55 </ol> 56 <li><a href="#problems">Common Problems</a> 57 <li><a href="#links">Links</a> 58 </ul> 59 60 <div class="doc_author"> 61 <p>Written by: 62 <a href="mailto:criswell (a] uiuc.edu">John Criswell</a>, 63 <a href="mailto:sabre (a] nondot.org">Chris Lattner</a>, 64 <a href="http://misha.brukman.net/">Misha Brukman</a>, 65 <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and 66 <a href="mailto:gshi1 (a] uiuc.edu">Guochun Shi</a>. 67 </p> 68 </div> 69 70 71 <!-- *********************************************************************** --> 72 <h2> 73 <a name="overview">Overview</a> 74 </h2> 75 <!-- *********************************************************************** --> 76 77 <div> 78 79 <p>Welcome to LLVM! In order to get started, you first need to know some 80 basic information.</p> 81 82 <p>First, LLVM comes in three pieces. The first piece is the LLVM 83 suite. This contains all of the tools, libraries, and header files 84 needed to use LLVM. It contains an assembler, disassembler, bitcode 85 analyzer and bitcode optimizer. It also contains basic regression tests that 86 can be used to test the LLVM tools and the Clang front end.</p> 87 88 <p>The second piece is the <a href="http://clang.llvm.org/">Clang</a> front end. 89 This component compiles C, C++, Objective C, and Objective C++ code into LLVM 90 bitcode. Once compiled into LLVM bitcode, a program can be manipulated with the 91 LLVM tools from the LLVM suite. 92 </p> 93 94 <p> 95 There is a third, optional piece called Test Suite. It is a suite of programs 96 with a testing harness that can be used to further test LLVM's functionality 97 and performance. 98 </p> 99 100 </div> 101 102 <!-- *********************************************************************** --> 103 <h2> 104 <a name="quickstart">Getting Started Quickly (A Summary)</a> 105 </h2> 106 <!-- *********************************************************************** --> 107 108 <div> 109 110 <p>The LLVM Getting Started documentation may be out of date. So, the Clang 111 <a href="http://clang.llvm.org/get_started.html">Getting Started</a> page might 112 also be a good place to start.</p> 113 114 <p>Here's the short story for getting up and running quickly with LLVM:</p> 115 116 <ol> 117 <li>Read the documentation.</li> 118 <li>Read the documentation.</li> 119 <li>Remember that you were warned twice about reading the documentation.</li> 120 121 <li>Checkout LLVM: 122 <ul> 123 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt> 124 <li><tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li> 125 </ul> 126 </li> 127 128 <li>Checkout Clang: 129 <ul> 130 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt> 131 <li><tt>cd llvm/tools</tt> 132 <li><tt>svn co http://llvm.org/svn/llvm-project/cfe/trunk clang</tt></li> 133 </ul> 134 </li> 135 136 <li>Checkout Compiler-RT: 137 <ul> 138 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt> 139 <li><tt>cd llvm/projects</tt> 140 <li><tt>svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk 141 compiler-rt</tt></li> 142 </ul> 143 </li> 144 145 <li>Get the Test Suite Source Code <b>[Optional]</b> 146 <ul> 147 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt> 148 <li><tt>cd llvm/projects</tt> 149 <li><tt>svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite</tt></li> 150 </ul> 151 </li> 152 153 <li>Configure and build LLVM and Clang: 154 <ul> 155 <li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li> 156 <li><tt>mkdir build</tt> (for building without polluting the source dir)</li> 157 <li><tt>cd build</tt></li> 158 <li><tt>../llvm/configure [options]</tt> 159 <br>Some common options: 160 161 <ul> 162 <li><tt>--prefix=<i>directory</i></tt> - 163 Specify for <i>directory</i> the full pathname of where you 164 want the LLVM tools and libraries to be installed (default 165 <tt>/usr/local</tt>).</li> 166 </ul> 167 168 <ul> 169 <li><tt>--enable-optimized</tt> - 170 Compile with optimizations enabled (default is NO).</li> 171 </ul> 172 173 <ul> 174 <li><tt>--enable-assertions</tt> - 175 Compile with assertion checks enabled (default is YES).</li> 176 </ul> 177 </li> 178 <li><tt>make [-j]</tt> - The -j specifies the number of jobs (commands) to 179 run simultaneously. This builds both LLVM and Clang for Debug+Asserts mode. 180 The --enabled-optimized configure option is used to specify a Release build.</li> 181 <li><tt>make check-all</tt> - 182 This run the regression tests to ensure everything is in working order.</li> 183 <li><tt>make update</tt> - 184 This command is used to update all the svn repositories at once, rather then 185 having to <tt>cd</tt> into the individual repositories and running 186 <tt>svn update</tt>.</li> 187 <li>It is also possible to use CMake instead of the makefiles. With CMake 188 it is also possible to generate project files for several IDEs: Eclipse 189 CDT4, CodeBlocks, Qt-Creator (use the CodeBlocks generator), KDevelop3.</li> 190 <li>If you get an "internal compiler error (ICE)" or test failures, see 191 <a href="#brokengcc">below</a>.</li> 192 193 </ul> 194 </li> 195 196 </ol> 197 198 <p>Consult the <a href="#starting">Getting Started with LLVM</a> section for 199 detailed information on configuring and compiling LLVM. See <a 200 href="#environment">Setting Up Your Environment</a> for tips that simplify 201 working with the Clang front end and LLVM tools. Go to <a href="#layout">Program 202 Layout</a> to learn about the layout of the source code tree.</p> 203 204 </div> 205 206 <!-- *********************************************************************** --> 207 <h2> 208 <a name="requirements">Requirements</a> 209 </h2> 210 <!-- *********************************************************************** --> 211 212 <div> 213 214 <p>Before you begin to use the LLVM system, review the requirements given below. 215 This may save you some trouble by knowing ahead of time what hardware and 216 software you will need.</p> 217 218 <!-- ======================================================================= --> 219 <h3> 220 <a name="hardware">Hardware</a> 221 </h3> 222 223 <div> 224 225 <p>LLVM is known to work on the following platforms:</p> 226 227 <table cellpadding="3" summary="Known LLVM platforms"> 228 <tr> 229 <th>OS</th> 230 <th>Arch</th> 231 <th>Compilers</th> 232 </tr> 233 <tr> 234 <td>AuroraUX</td> 235 <td>x86<sup><a href="#pf_1">1</a></sup></td> 236 <td>GCC</td> 237 </tr> 238 <tr> 239 <td>Linux</td> 240 <td>x86<sup><a href="#pf_1">1</a></sup></td> 241 <td>GCC</td> 242 </tr> 243 <tr> 244 <td>Linux</td> 245 <td>amd64</td> 246 <td>GCC</td> 247 </tr> 248 <tr> 249 <td>Solaris</td> 250 <td>V9 (Ultrasparc)</td> 251 <td>GCC</td> 252 </tr> 253 <tr> 254 <td>FreeBSD</td> 255 <td>x86<sup><a href="#pf_1">1</a></sup></td> 256 <td>GCC</td> 257 </tr> 258 <tr> 259 <td>FreeBSD</td> 260 <td>amd64</td> 261 <td>GCC</td> 262 </tr> 263 <tr> 264 <td>MacOS X<sup><a href="#pf_2">2</a></sup></td> 265 <td>PowerPC</td> 266 <td>GCC</td> 267 </tr> 268 <tr> 269 <td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td> 270 <td>x86</td> 271 <td>GCC</td> 272 </tr> 273 <tr> 274 <td>Cygwin/Win32</td> 275 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a>, 276 <a href="#pf_11">11</a></sup></td> 277 <td>GCC 3.4.X, binutils 2.20</td> 278 </tr> 279 <tr> 280 <td>MinGW/Win32</td> 281 <td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>, 282 <a href="#pf_8">8</a>, <a href="#pf_10">10</a>, 283 <a href="#pf_11">11</a></sup></td> 284 <td>GCC 3.4.X, binutils 2.20</td> 285 </tr> 286 </table> 287 288 <p>LLVM has partial support for the following platforms:</p> 289 290 <table summary="LLVM partial platform support"> 291 <tr> 292 <th>OS</th> 293 <th>Arch</th> 294 <th>Compilers</th> 295 </tr> 296 <tr> 297 <td>Windows</td> 298 <td>x86<sup><a href="#pf_1">1</a></sup></td> 299 <td>Visual Studio 2008 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td> 300 <tr> 301 <td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td> 302 <td>PowerPC</td> 303 <td>GCC</td> 304 </tr> 305 <tr> 306 <td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td> 307 <td>PowerPC</td> 308 <td>GCC</td> 309 </tr> 310 311 <tr> 312 <td>Linux<sup><a href="#pf_7">7</a></sup></td> 313 <td>Alpha</td> 314 <td>GCC</td> 315 </tr> 316 <tr> 317 <td>Linux<sup><a href="#pf_7">7</a></sup></td> 318 <td>Itanium (IA-64)</td> 319 <td>GCC</td> 320 </tr> 321 <tr> 322 <td>HP-UX<sup><a href="#pf_7">7</a></sup></td> 323 <td>Itanium (IA-64)</td> 324 <td>HP aCC</td> 325 </tr> 326 <tr> 327 <td>Windows x64</td> 328 <td>x86-64</td> 329 <td>mingw-w64's GCC-4.5.x<sup><a href="#pf_12">12</a></sup></td> 330 </tr> 331 </table> 332 333 <p><b>Notes:</b></p> 334 335 <div class="doc_notes"> 336 <ol> 337 <li><a name="pf_1">Code generation supported for Pentium processors and 338 up</a></li> 339 <li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li> 340 <li><a name="pf_3">No native code generation</a></li> 341 <li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li> 342 <li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li> 343 <li><a name="pf_6">The port is done using the MSYS shell.</a></li> 344 <li><a name="pf_7">Native code generation exists but is not complete.</a></li> 345 <li><a name="pf_8">Binutils 2.20 or later is required to build the assembler 346 generated by LLVM properly.</a></li> 347 <li><a name="pf_9">XCode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip 348 internal LLVM assert messages when compiled for Release at optimization 349 levels greater than 0 (i.e., <i>"-O1"</i> and higher). 350 Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line 351 if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li> 352 <li><a name="pf_10">For MSYS/MinGW on Windows, be sure to install the MSYS 353 version of the perl package, and be sure it appears in your path 354 before any Windows-based versions such as Strawberry Perl and 355 ActivePerl, as these have Windows-specifics that will cause the 356 build to fail.</a></li> 357 <li><a name="pf_11">To use LLVM modules on Win32-based system, 358 you may configure LLVM with <i>"--enable-shared"</i>.</a></li> 359 <li><a name="pf_12">To compile SPU backend, you need to add 360 <tt>"LDFLAGS=-Wl,--stack,16777216"</tt> to configure.</a></li> 361 </ol> 362 </div> 363 364 <p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug 365 mode, depending on the system (it is so large because of all the debugging 366 information and the fact that the libraries are statically linked into multiple 367 tools). If you do not need many of the tools and you are space-conscious, you 368 can pass <tt>ONLY_TOOLS="tools you need"</tt> to make. The Release build 369 requires considerably less space.</p> 370 371 <p>The LLVM suite <i>may</i> compile on other platforms, but it is not 372 guaranteed to do so. If compilation is successful, the LLVM utilities should be 373 able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code 374 generation should work as well, although the generated native code may not work 375 on your platform.</p> 376 377 </div> 378 379 <!-- ======================================================================= --> 380 <h3> 381 <a name="software">Software</a> 382 </h3> 383 <div> 384 <p>Compiling LLVM requires that you have several software packages 385 installed. The table below lists those required packages. The Package column 386 is the usual name for the software package that LLVM depends on. The Version 387 column provides "known to work" versions of the package. The Notes column 388 describes how LLVM uses the package and provides other details.</p> 389 <table summary="Packages required to compile LLVM"> 390 <tr><th>Package</th><th>Version</th><th>Notes</th></tr> 391 392 <tr> 393 <td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td> 394 <td>3.79, 3.79.1</td> 395 <td>Makefile/build processor</td> 396 </tr> 397 398 <tr> 399 <td><a href="http://gcc.gnu.org/">GCC</a></td> 400 <td>3.4.2</td> 401 <td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td> 402 </tr> 403 404 <tr> 405 <td><a href="http://www.gnu.org/software/texinfo/">TeXinfo</a></td> 406 <td>4.5</td> 407 <td>For building the CFE</td> 408 </tr> 409 410 <tr> 411 <td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td> 412 <td>≥1.3</td> 413 <td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td> 414 </tr> 415 416 <!-- FIXME: 417 Do we support dg? 418 Are DejaGnu and expect obsolete? 419 Shall we mention Python? --> 420 421 <tr> 422 <td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td> 423 <td>1.4.2</td> 424 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td> 425 </tr> 426 427 <tr> 428 <td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td> 429 <td>8.3, 8.4</td> 430 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td> 431 </tr> 432 433 <tr> 434 <td><a href="http://expect.nist.gov/">expect</a></td> 435 <td>5.38.0</td> 436 <td>Automated test suite<sup><a href="#sf3">3</a></sup></td> 437 </tr> 438 439 <tr> 440 <td><a href="http://www.perl.com/download.csp">perl</a></td> 441 <td>≥5.6.0</td> 442 <td>Utilities</td> 443 </tr> 444 445 <tr> 446 <td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a> 447 <td>1.4</td> 448 <td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td> 449 </tr> 450 451 <tr> 452 <td><a href="http://www.gnu.org/software/autoconf/">GNU Autoconf</a></td> 453 <td>2.60</td> 454 <td>Configuration script builder<sup><a href="#sf4">4</a></sup></td> 455 </tr> 456 457 <tr> 458 <td><a href="http://www.gnu.org/software/automake/">GNU Automake</a></td> 459 <td>1.9.6</td> 460 <td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td> 461 </tr> 462 463 <tr> 464 <td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td> 465 <td>1.5.22</td> 466 <td>Shared library manager<sup><a href="#sf4">4</a></sup></td> 467 </tr> 468 469 </table> 470 471 <p><b>Notes:</b></p> 472 <div class="doc_notes"> 473 <ol> 474 <li><a name="sf1">Only the C and C++ languages are needed so there's no 475 need to build the other languages for LLVM's purposes.</a> See 476 <a href="#brokengcc">below</a> for specific version info.</li> 477 <li><a name="sf2">You only need Subversion if you intend to build from the 478 latest LLVM sources. If you're working from a release distribution, you 479 don't need Subversion.</a></li> 480 <li><a name="sf3">Only needed if you want to run the automated test 481 suite in the <tt>llvm/test</tt> directory.</a></li> 482 <li><a name="sf4">If you want to make changes to the configure scripts, 483 you will need GNU autoconf (2.60), and consequently, GNU M4 (version 1.4 484 or higher). You will also need automake (1.9.6). We only use aclocal 485 from that package.</a></li> 486 </ol> 487 </div> 488 489 <p>Additionally, your compilation host is expected to have the usual 490 plethora of Unix utilities. Specifically:</p> 491 <ul> 492 <li><b>ar</b> - archive library builder</li> 493 <li><b>bzip2*</b> - bzip2 command for distribution generation</li> 494 <li><b>bunzip2*</b> - bunzip2 command for distribution checking</li> 495 <li><b>chmod</b> - change permissions on a file</li> 496 <li><b>cat</b> - output concatenation utility</li> 497 <li><b>cp</b> - copy files</li> 498 <li><b>date</b> - print the current date/time </li> 499 <li><b>echo</b> - print to standard output</li> 500 <li><b>egrep</b> - extended regular expression search utility</li> 501 <li><b>find</b> - find files/dirs in a file system</li> 502 <li><b>grep</b> - regular expression search utility</li> 503 <li><b>gzip*</b> - gzip command for distribution generation</li> 504 <li><b>gunzip*</b> - gunzip command for distribution checking</li> 505 <li><b>install</b> - install directories/files </li> 506 <li><b>mkdir</b> - create a directory</li> 507 <li><b>mv</b> - move (rename) files</li> 508 <li><b>ranlib</b> - symbol table builder for archive libraries</li> 509 <li><b>rm</b> - remove (delete) files and directories</li> 510 <li><b>sed</b> - stream editor for transforming output</li> 511 <li><b>sh</b> - Bourne shell for make build scripts</li> 512 <li><b>tar</b> - tape archive for distribution generation</li> 513 <li><b>test</b> - test things in file system</li> 514 <li><b>unzip*</b> - unzip command for distribution checking</li> 515 <li><b>zip*</b> - zip command for distribution generation</li> 516 </ul> 517 </div> 518 519 <!-- ======================================================================= --> 520 <h3> 521 <a name="brokengcc">Broken versions of GCC and other tools</a> 522 </h3> 523 524 <div> 525 526 <p>LLVM is very demanding of the host C++ compiler, and as such tends to expose 527 bugs in the compiler. In particular, several versions of GCC crash when trying 528 to compile LLVM. We routinely use GCC 4.2 (and higher) or Clang. 529 Other versions of GCC will probably work as well. GCC versions listed 530 here are known to not work. If you are using one of these versions, please try 531 to upgrade your GCC to something more recent. If you run into a problem with a 532 version of GCC not listed here, please <a href="mailto:llvmdev (a] cs.uiuc.edu">let 533 us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version 534 of GCC you are using. 535 </p> 536 537 <p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several 538 problems in the STL that effectively prevent it from compiling LLVM. 539 </p> 540 541 <p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with 542 a bogus template error. This was fixed in later GCCs.</p> 543 544 <p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a 545 href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in 546 the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p> 547 548 <p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with 549 Cygwin does not work.</p> 550 <p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and 551 possibly others) does not compile LLVM correctly (it appears that exception 552 handling is broken in some cases). Please download the FSF 3.3.3 or upgrade 553 to a newer version of GCC.</p> 554 <p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the 555 code generator, causing an infinite loop in the llvm-gcc build when built 556 with optimizations enabled (i.e. a release build).</p> 557 <p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the 558 code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0) 559 correctly compiles LLVM at -O2. A work around is to build release LLVM 560 builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p> 561 <p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056"> 562 miscompiles portions of LLVM</a>.</p> 563 <p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM 564 when building with optimizations enabled. It appears to work with 565 "<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug 566 build.</p> 567 <p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to 568 miscompile LLVM.</p> 569 <p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the 570 default with ENABLE_OPTIMIZED=1. To work around this, build with 571 "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p> 572 <p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors 573 compiling some files. At the time of this writing, GCC mainline (4.2) 574 did not share the problem.</p> 575 <p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063"> 576 miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit 577 code. LLVM will appear to mostly work but will be buggy, e.g. failing 578 portions of its testsuite.</p> 579 <p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64 580 platforms compiling md5.c gets a mangled constant.</p> 581 <p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears 582 to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining 583 about symbols remaining in the table on destruction.</p> 584 <p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms 585 as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p> 586 <p><b>Cygwin GCC 4.3.2 20080827 (beta) 2</b>: 587 Users <a href="http://llvm.org/PR4145">reported</a> various problems related 588 with link errors when using this GCC version.</p> 589 <p><b>Debian GCC 4.3.2 on X86</b>: Crashes building some files in LLVM 2.6.</p> 590 <p><b>GCC 4.3.3 (Debian 4.3.3-10) on ARM</b>: Miscompiles parts of LLVM 2.6 591 when optimizations are turned on. The symptom is an infinite loop in 592 FoldingSetImpl::RemoveNode while running the code generator.</p> 593 <p><b>GCC 4.3.5 and GCC 4.4.5 on ARM</b>: These can miscompile <tt>value >> 594 1</tt> even at -O0. A test failure in <tt>test/Assembler/alignstack.ll</tt> is 595 one symptom of the problem. 596 <p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very 597 long warning messages complaining that some ".gnu.linkonce.t.*" symbol was 598 defined in a discarded section. You can safely ignore these messages as they are 599 erroneous and the linkage is correct. These messages disappear using ld 600 2.17.</p> 601 602 <p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a 603 href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which 604 causes huge link times (minutes instead of seconds) when building LLVM. We 605 recommend upgrading to a newer version (2.17.50.0.4 or later).</p> 606 607 <p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained 608 <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a> 609 which causes intermittent failures when building LLVM with position independent 610 code. The symptom is an error about cyclic dependencies. We recommend 611 upgrading to a newer version of Gold.</p> 612 613 </div> 614 615 </div> 616 617 <!-- *********************************************************************** --> 618 <h2> 619 <a name="starting">Getting Started with LLVM</a> 620 </h2> 621 <!-- *********************************************************************** --> 622 623 <div> 624 625 <p>The remainder of this guide is meant to get you up and running with 626 LLVM and to give you some basic information about the LLVM environment.</p> 627 628 <p>The later sections of this guide describe the <a 629 href="#layout">general layout</a> of the the LLVM source tree, a <a 630 href="#tutorial">simple example</a> using the LLVM tool chain, and <a 631 href="#links">links</a> to find more information about LLVM or to get 632 help via e-mail.</p> 633 634 <!-- ======================================================================= --> 635 <h3> 636 <a name="terminology">Terminology and Notation</a> 637 </h3> 638 639 <div> 640 641 <p>Throughout this manual, the following names are used to denote paths 642 specific to the local system and working environment. <i>These are not 643 environment variables you need to set but just strings used in the rest 644 of this document below</i>. In any of the examples below, simply replace 645 each of these names with the appropriate pathname on your local system. 646 All these paths are absolute:</p> 647 648 <dl> 649 <dt>SRC_ROOT 650 <dd> 651 This is the top level directory of the LLVM source tree. 652 <br><br> 653 654 <dt>OBJ_ROOT 655 <dd> 656 This is the top level directory of the LLVM object tree (i.e. the 657 tree where object files and compiled programs will be placed. It 658 can be the same as SRC_ROOT). 659 <br><br> 660 661 </dl> 662 663 </div> 664 665 <!-- ======================================================================= --> 666 <h3> 667 <a name="environment">Setting Up Your Environment</a> 668 </h3> 669 670 <div> 671 672 <p> 673 In order to compile and use LLVM, you may need to set some environment 674 variables. 675 676 <dl> 677 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt> 678 <dd>[Optional] This environment variable helps LLVM linking tools find the 679 locations of your bitcode libraries. It is provided only as a 680 convenience since you can specify the paths using the -L options of the 681 tools and the C/C++ front-end will automatically use the bitcode files 682 installed in its 683 <tt>lib</tt> directory.</dd> 684 </dl> 685 686 </div> 687 688 <!-- ======================================================================= --> 689 <h3> 690 <a name="unpack">Unpacking the LLVM Archives</a> 691 </h3> 692 693 <div> 694 695 <p> 696 If you have the LLVM distribution, you will need to unpack it before you 697 can begin to compile it. LLVM is distributed as a set of two files: the LLVM 698 suite and the LLVM GCC front end compiled for your platform. There is an 699 additional test suite that is optional. Each file is a TAR archive that is 700 compressed with the gzip program. 701 </p> 702 703 <p>The files are as follows, with <em>x.y</em> marking the version number: 704 <dl> 705 <dt><tt>llvm-x.y.tar.gz</tt></dt> 706 <dd>Source release for the LLVM libraries and tools.<br></dd> 707 708 <dt><tt>llvm-test-x.y.tar.gz</tt></dt> 709 <dd>Source release for the LLVM test-suite.</dd> 710 711 <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt> 712 <dd>Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root 713 directory for build instructions.<br></dd> 714 715 <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt> 716 <dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd> 717 718 </dl> 719 720 </div> 721 722 <!-- ======================================================================= --> 723 <h3> 724 <a name="checkout">Checkout LLVM from Subversion</a> 725 </h3> 726 727 <div> 728 729 <p>If you have access to our Subversion repository, you can get a fresh copy of 730 the entire source code. All you need to do is check it out from Subversion as 731 follows:</p> 732 733 <ul> 734 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li> 735 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li> 736 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk 737 llvm</tt></li> 738 </ul> 739 740 741 <p>This will create an '<tt>llvm</tt>' directory in the current 742 directory and fully populate it with the LLVM source code, Makefiles, 743 test directories, and local copies of documentation files.</p> 744 745 <p>If you want to get a specific release (as opposed to the most recent 746 revision), you can checkout it from the '<tt>tags</tt>' directory (instead of 747 '<tt>trunk</tt>'). The following releases are located in the following 748 subdirectories of the '<tt>tags</tt>' directory:</p> 749 750 <ul> 751 <li>Release 2.9: <b>RELEASE_29/final</b></li> 752 <li>Release 2.8: <b>RELEASE_28</b></li> 753 <li>Release 2.7: <b>RELEASE_27</b></li> 754 <li>Release 2.6: <b>RELEASE_26</b></li> 755 <li>Release 2.5: <b>RELEASE_25</b></li> 756 <li>Release 2.4: <b>RELEASE_24</b></li> 757 <li>Release 2.3: <b>RELEASE_23</b></li> 758 <li>Release 2.2: <b>RELEASE_22</b></li> 759 <li>Release 2.1: <b>RELEASE_21</b></li> 760 <li>Release 2.0: <b>RELEASE_20</b></li> 761 <li>Release 1.9: <b>RELEASE_19</b></li> 762 <li>Release 1.8: <b>RELEASE_18</b></li> 763 <li>Release 1.7: <b>RELEASE_17</b></li> 764 <li>Release 1.6: <b>RELEASE_16</b></li> 765 <li>Release 1.5: <b>RELEASE_15</b></li> 766 <li>Release 1.4: <b>RELEASE_14</b></li> 767 <li>Release 1.3: <b>RELEASE_13</b></li> 768 <li>Release 1.2: <b>RELEASE_12</b></li> 769 <li>Release 1.1: <b>RELEASE_11</b></li> 770 <li>Release 1.0: <b>RELEASE_1</b></li> 771 </ul> 772 773 <p>If you would like to get the LLVM test suite (a separate package as of 1.4), 774 you get it from the Subversion repository:</p> 775 776 <div class="doc_code"> 777 <pre> 778 % cd llvm/projects 779 % svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite 780 </pre> 781 </div> 782 783 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically 784 configured by the LLVM configure script as well as automatically updated when 785 you run <tt>svn update</tt>.</p> 786 787 </div> 788 789 <!-- ======================================================================= --> 790 <h3> 791 <a name="git_mirror">GIT mirror</a> 792 </h3> 793 794 <div> 795 796 <p>GIT mirrors are available for a number of LLVM subprojects. These mirrors 797 sync automatically with each Subversion commit and contain all necessary 798 git-svn marks (so, you can recreate git-svn metadata locally). Note that right 799 now mirrors reflect only <tt>trunk</tt> for each project. You can do the 800 read-only GIT clone of LLVM via:</p> 801 802 <pre class="doc_code"> 803 git clone http://llvm.org/git/llvm.git 804 </pre> 805 806 <p>If you want to check out clang too, run:</p> 807 808 <pre class="doc_code"> 809 git clone http://llvm.org/git/llvm.git 810 cd llvm/tools 811 git clone http://llvm.org/git/clang.git 812 </pre> 813 814 <p> 815 Since the upstream repository is in Subversion, you should use 816 <tt>"git pull --rebase"</tt> 817 instead of <tt>"git pull"</tt> to avoid generating a non-linear 818 history in your clone. 819 To configure <tt>"git pull"</tt> to pass <tt>--rebase</tt> by default 820 on the master branch, run the following command: 821 </p> 822 823 <pre class="doc_code"> 824 git config branch.master.rebase true 825 </pre> 826 827 <h4>Sending patches with Git</h4> 828 <div> 829 <p> 830 Please read <a href="DeveloperPolicy.html#patches">Developer Policy</a>, too. 831 </p> 832 833 <p> 834 Assume <tt>master</tt> points the upstream and <tt>mybranch</tt> points your 835 working branch, and <tt>mybranch</tt> is rebased onto <tt>master</tt>. 836 At first you may check sanity of whitespaces: 837 </p> 838 839 <pre class="doc_code"> 840 git diff --check master..mybranch 841 </pre> 842 843 <p> 844 The easiest way to generate a patch is as below: 845 </p> 846 847 <pre class="doc_code"> 848 git diff master..mybranch > /path/to/mybranch.diff 849 </pre> 850 851 <p> 852 It is a little different from svn-generated diff. git-diff-generated diff has 853 prefixes like <tt>a/</tt> and <tt>b/</tt>. Don't worry, most developers might 854 know it could be accepted with <tt>patch -p1 -N</tt>. 855 </p> 856 857 <p> 858 But you may generate patchset with git-format-patch. It generates 859 by-each-commit patchset. To generate patch files to attach to your article: 860 </p> 861 862 <pre class="doc_code"> 863 git format-patch --no-attach master..mybranch -o /path/to/your/patchset 864 </pre> 865 866 <p> 867 If you would like to send patches directly, you may use git-send-email or 868 git-imap-send. Here is an example to generate the patchset in Gmail's [Drafts]. 869 </p> 870 871 <pre class="doc_code"> 872 git format-patch --attach master..mybranch --stdout | git imap-send 873 </pre> 874 875 <p> 876 Then, your .git/config should have [imap] sections. 877 </p> 878 879 <pre class="doc_code"> 880 [imap] 881 host = imaps://imap.gmail.com 882 user = <em>your.gmail.account</em>@gmail.com 883 pass = <em>himitsu!</em> 884 port = 993 885 sslverify = false 886 ; in English 887 folder = "[Gmail]/Drafts" 888 ; example for Japanese, "Modified UTF-7" encoded. 889 folder = "[Gmail]/&Tgtm+DBN-" 890 ; example for Traditional Chinese 891 folder = "[Gmail]/&g0l6Pw-" 892 </pre> 893 894 </div> 895 896 <h4>For developers to work with git-svn</h4> 897 <div> 898 899 <p>To set up clone from which you can submit code using 900 <tt>git-svn</tt>, run:</p> 901 902 <pre class="doc_code"> 903 git clone http://llvm.org/git/llvm.git 904 cd llvm 905 git svn init https://llvm.org/svn/llvm-project/llvm/trunk --username=<username> 906 git config svn-remote.svn.fetch :refs/remotes/origin/master 907 git svn rebase -l # -l avoids fetching ahead of the git mirror. 908 909 # If you have clang too: 910 cd tools 911 git clone http://llvm.org/git/clang.git 912 cd clang 913 git svn init https://llvm.org/svn/llvm-project/cfe/trunk --username=<username> 914 git config svn-remote.svn.fetch :refs/remotes/origin/master 915 git svn rebase -l 916 </pre> 917 918 <p>To update this clone without generating git-svn tags that conflict 919 with the upstream git repo, run:</p> 920 921 <pre class="doc_code"> 922 git fetch && (cd tools/clang && git fetch) # Get matching revisions of both trees. 923 git checkout master 924 git svn rebase -l 925 (cd tools/clang && 926 git checkout master && 927 git svn rebase -l) 928 </pre> 929 930 <p>This leaves your working directories on their master branches, so 931 you'll need to <tt>checkout</tt> each working branch individually and 932 <tt>rebase</tt> it on top of its parent branch. (Note: This script is 933 intended for relative newbies to git. If you have more experience, 934 you can likely improve on it.)</p> 935 936 <p>The git-svn metadata can get out of sync after you mess around with 937 branches and <code>dcommit</code>. When that happens, <code>git svn 938 dcommit</code> stops working, complaining about files with uncommitted 939 changes. The fix is to rebuild the metadata:</p> 940 941 <pre class="doc_code"> 942 rm -rf .git/svn 943 git svn rebase -l 944 </pre> 945 946 </div> 947 948 </div> 949 950 <!-- ======================================================================= --> 951 <h3> 952 <a name="config">Local LLVM Configuration</a> 953 </h3> 954 955 <div> 956 957 <p>Once checked out from the Subversion repository, the LLVM suite source 958 code must be 959 configured via the <tt>configure</tt> script. This script sets variables in the 960 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and 961 <tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with 962 the Makefiles needed to begin building LLVM.</p> 963 964 <p>The following environment variables are used by the <tt>configure</tt> 965 script to configure the build system:</p> 966 967 <table summary="LLVM configure script environment variables"> 968 <tr><th>Variable</th><th>Purpose</th></tr> 969 <tr> 970 <td>CC</td> 971 <td>Tells <tt>configure</tt> which C compiler to use. By default, 972 <tt>configure</tt> will look for the first GCC C compiler in 973 <tt>PATH</tt>. Use this variable to override 974 <tt>configure</tt>'s default behavior.</td> 975 </tr> 976 <tr> 977 <td>CXX</td> 978 <td>Tells <tt>configure</tt> which C++ compiler to use. By default, 979 <tt>configure</tt> will look for the first GCC C++ compiler in 980 <tt>PATH</tt>. Use this variable to override 981 <tt>configure</tt>'s default behavior.</td> 982 </tr> 983 </table> 984 985 <p>The following options can be used to set or enable LLVM specific options:</p> 986 987 <dl> 988 <dt><i>--enable-optimized</i></dt> 989 <dd> 990 Enables optimized compilation (debugging symbols are removed 991 and GCC optimization flags are enabled). Note that this is the default 992 setting if you are using the LLVM distribution. The default behavior 993 of an Subversion checkout is to use an unoptimized build (also known as a 994 debug build). 995 <br><br> 996 </dd> 997 <dt><i>--enable-debug-runtime</i></dt> 998 <dd> 999 Enables debug symbols in the runtime libraries. The default is to strip 1000 debug symbols from the runtime libraries. 1001 </dd> 1002 <dt><i>--enable-jit</i></dt> 1003 <dd> 1004 Compile the Just In Time (JIT) compiler functionality. This is not 1005 available 1006 on all platforms. The default is dependent on platform, so it is best 1007 to explicitly enable it if you want it. 1008 <br><br> 1009 </dd> 1010 <dt><i>--enable-targets=</i><tt>target-option</tt></dt> 1011 <dd>Controls which targets will be built and linked into llc. The default 1012 value for <tt>target_options</tt> is "all" which builds and links all 1013 available targets. The value "host-only" can be specified to build only a 1014 native compiler (no cross-compiler targets available). The "native" target is 1015 selected as the target of the build host. You can also specify a comma 1016 separated list of target names that you want available in llc. The target 1017 names use all lower case. The current set of targets is: <br> 1018 <tt>arm, cbe, cpp, hexagon, mblaze, mips, mipsel, msp430, powerpc, ptx, sparc, spu, x86, x86_64, xcore</tt>. 1019 <br><br></dd> 1020 <dt><i>--enable-doxygen</i></dt> 1021 <dd>Look for the doxygen program and enable construction of doxygen based 1022 documentation from the source code. This is disabled by default because 1023 generating the documentation can take a long time and producess 100s of 1024 megabytes of output.</dd> 1025 <dt><i>--with-udis86</i></dt> 1026 <dd>LLVM can use external disassembler library for various purposes (now it's 1027 used only for examining code produced by JIT). This option will enable usage 1028 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64 1029 bits) disassembler library.</dd> 1030 </dl> 1031 1032 <p>To configure LLVM, follow these steps:</p> 1033 1034 <ol> 1035 <li><p>Change directory into the object root directory:</p> 1036 1037 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li> 1038 1039 <li><p>Run the <tt>configure</tt> script located in the LLVM source 1040 tree:</p> 1041 1042 <div class="doc_code"> 1043 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre> 1044 </div></li> 1045 </ol> 1046 1047 </div> 1048 1049 <!-- ======================================================================= --> 1050 <h3> 1051 <a name="compile">Compiling the LLVM Suite Source Code</a> 1052 </h3> 1053 1054 <div> 1055 1056 <p>Once you have configured LLVM, you can build it. There are three types of 1057 builds:</p> 1058 1059 <dl> 1060 <dt>Debug Builds 1061 <dd> 1062 These builds are the default when one is using an Subversion checkout and 1063 types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was 1064 used during configuration). The build system will compile the tools and 1065 libraries with debugging information. To get a Debug Build using the 1066 LLVM distribution the <tt>--disable-optimized</tt> option must be passed 1067 to <tt>configure</tt>. 1068 <br><br> 1069 1070 <dt>Release (Optimized) Builds 1071 <dd> 1072 These builds are enabled with the <tt>--enable-optimized</tt> option to 1073 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the 1074 <tt>gmake</tt> command line. For these builds, the build system will 1075 compile the tools and libraries with GCC optimizations enabled and strip 1076 debugging information from the libraries and executables it generates. 1077 Note that Release Builds are default when using an LLVM distribution. 1078 <br><br> 1079 1080 <dt>Profile Builds 1081 <dd> 1082 These builds are for use with profiling. They compile profiling 1083 information into the code for use with programs like <tt>gprof</tt>. 1084 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt> 1085 on the <tt>gmake</tt> command line. 1086 </dl> 1087 1088 <p>Once you have LLVM configured, you can build it by entering the 1089 <i>OBJ_ROOT</i> directory and issuing the following command:</p> 1090 1091 <div class="doc_code"><pre>% gmake</pre></div> 1092 1093 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you 1094 are using a version of GCC that is known not to compile LLVM.</p> 1095 1096 <p> 1097 If you have multiple processors in your machine, you may wish to use some of 1098 the parallel build options provided by GNU Make. For example, you could use the 1099 command:</p> 1100 1101 <div class="doc_code"><pre>% gmake -j2</pre></div> 1102 1103 <p>There are several special targets which are useful when working with the LLVM 1104 source code:</p> 1105 1106 <dl> 1107 <dt><tt>gmake clean</tt> 1108 <dd> 1109 Removes all files generated by the build. This includes object files, 1110 generated C/C++ files, libraries, and executables. 1111 <br><br> 1112 1113 <dt><tt>gmake dist-clean</tt> 1114 <dd> 1115 Removes everything that <tt>gmake clean</tt> does, but also removes files 1116 generated by <tt>configure</tt>. It attempts to return the source tree to the 1117 original state in which it was shipped. 1118 <br><br> 1119 1120 <dt><tt>gmake install</tt> 1121 <dd> 1122 Installs LLVM header files, libraries, tools, and documentation in a 1123 hierarchy 1124 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which 1125 defaults to <tt>/usr/local</tt>. 1126 <br><br> 1127 1128 <dt><tt>gmake -C runtime install-bytecode</tt> 1129 <dd> 1130 Assuming you built LLVM into $OBJDIR, when this command is run, it will 1131 install bitcode libraries into the GCC front end's bitcode library 1132 directory. If you need to update your bitcode libraries, 1133 this is the target to use once you've built them. 1134 <br><br> 1135 </dl> 1136 1137 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further 1138 details on these <tt>make</tt> targets and descriptions of other targets 1139 available.</p> 1140 1141 <p>It is also possible to override default values from <tt>configure</tt> by 1142 declaring variables on the command line. The following are some examples:</p> 1143 1144 <dl> 1145 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt> 1146 <dd> 1147 Perform a Release (Optimized) build. 1148 <br><br> 1149 1150 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt> 1151 <dd> 1152 Perform a Release (Optimized) build without assertions enabled. 1153 <br><br> 1154 1155 <dt><tt>gmake ENABLE_OPTIMIZED=0</tt> 1156 <dd> 1157 Perform a Debug build. 1158 <br><br> 1159 1160 <dt><tt>gmake ENABLE_PROFILING=1</tt> 1161 <dd> 1162 Perform a Profiling build. 1163 <br><br> 1164 1165 <dt><tt>gmake VERBOSE=1</tt> 1166 <dd> 1167 Print what <tt>gmake</tt> is doing on standard output. 1168 <br><br> 1169 1170 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt> 1171 <dd>Ask each tool invoked by the makefiles to print out what it is doing on 1172 the standard output. This also implies <tt>VERBOSE=1</tt>. 1173 <br><br></dd> 1174 </dl> 1175 1176 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build 1177 it and any subdirectories that it contains. Entering any directory inside the 1178 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below 1179 that directory that is out of date.</p> 1180 1181 </div> 1182 1183 <!-- ======================================================================= --> 1184 <h3> 1185 <a name="cross-compile">Cross-Compiling LLVM</a> 1186 </h3> 1187 1188 <div> 1189 <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM 1190 executables and libraries to be hosted on a platform different from the 1191 platform where they are build (a Canadian Cross build). To configure a 1192 cross-compile, supply the configure script with <tt>--build</tt> and 1193 <tt>--host</tt> options that are different. The values of these options must 1194 be legal target triples that your GCC compiler supports.</p> 1195 1196 <p>The result of such a build is executables that are not runnable on 1197 on the build host (--build option) but can be executed on the compile host 1198 (--host option).</p> 1199 </div> 1200 1201 <!-- ======================================================================= --> 1202 <h3> 1203 <a name="objfiles">The Location of LLVM Object Files</a> 1204 </h3> 1205 1206 <div> 1207 1208 <p>The LLVM build system is capable of sharing a single LLVM source tree among 1209 several LLVM builds. Hence, it is possible to build LLVM for several different 1210 platforms or configurations using the same source tree.</p> 1211 1212 <p>This is accomplished in the typical autoconf manner:</p> 1213 1214 <ul> 1215 <li><p>Change directory to where the LLVM object files should live:</p> 1216 1217 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li> 1218 1219 <li><p>Run the <tt>configure</tt> script found in the LLVM source 1220 directory:</p> 1221 1222 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li> 1223 </ul> 1224 1225 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories 1226 named after the build type:</p> 1227 1228 <dl> 1229 <dt>Debug Builds with assertions enabled (the default) 1230 <dd> 1231 <dl> 1232 <dt>Tools 1233 <dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/bin</tt> 1234 <dt>Libraries 1235 <dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/lib</tt> 1236 </dl> 1237 <br><br> 1238 1239 <dt>Release Builds 1240 <dd> 1241 <dl> 1242 <dt>Tools 1243 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt> 1244 <dt>Libraries 1245 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt> 1246 </dl> 1247 <br><br> 1248 1249 <dt>Profile Builds 1250 <dd> 1251 <dl> 1252 <dt>Tools 1253 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt> 1254 <dt>Libraries 1255 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt> 1256 </dl> 1257 </dl> 1258 1259 </div> 1260 1261 <!-- ======================================================================= --> 1262 <h3> 1263 <a name="optionalconfig">Optional Configuration Items</a> 1264 </h3> 1265 1266 <div> 1267 1268 <p> 1269 If you're running on a Linux system that supports the "<a 1270 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>" 1271 module, and you have root access on the system, you can set your system up to 1272 execute LLVM bitcode files directly. To do this, use commands like this (the 1273 first command may not be required if you are already using the module):</p> 1274 1275 <div class="doc_code"> 1276 <pre> 1277 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc 1278 $ echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register 1279 $ chmod u+x hello.bc (if needed) 1280 $ ./hello.bc 1281 </pre> 1282 </div> 1283 1284 <p> 1285 This allows you to execute LLVM bitcode files directly. On Debian, you 1286 can also use this command instead of the 'echo' command above: 1287 </p> 1288 1289 <div class="doc_code"> 1290 <pre> 1291 $ sudo update-binfmts --install llvm /path/to/lli --magic 'BC' 1292 </pre> 1293 </div> 1294 1295 </div> 1296 1297 </div> 1298 1299 <!-- *********************************************************************** --> 1300 <h2> 1301 <a name="layout">Program Layout</a> 1302 </h2> 1303 <!-- *********************************************************************** --> 1304 1305 <div> 1306 1307 <p>One useful source of information about the LLVM source base is the LLVM <a 1308 href="http://www.doxygen.org/">doxygen</a> documentation available at <tt><a 1309 href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>. 1310 The following is a brief introduction to code layout:</p> 1311 1312 <!-- ======================================================================= --> 1313 <h3> 1314 <a name="examples"><tt>llvm/examples</tt></a> 1315 </h3> 1316 1317 <div> 1318 <p>This directory contains some simple examples of how to use the LLVM IR and 1319 JIT.</p> 1320 </div> 1321 1322 <!-- ======================================================================= --> 1323 <h3> 1324 <a name="include"><tt>llvm/include</tt></a> 1325 </h3> 1326 1327 <div> 1328 1329 <p>This directory contains public header files exported from the LLVM 1330 library. The three main subdirectories of this directory are:</p> 1331 1332 <dl> 1333 <dt><tt><b>llvm/include/llvm</b></tt></dt> 1334 <dd>This directory contains all of the LLVM specific header files. This 1335 directory also has subdirectories for different portions of LLVM: 1336 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>, 1337 etc...</dd> 1338 1339 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt> 1340 <dd>This directory contains generic support libraries that are provided with 1341 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities 1342 and a Command Line option processing library store their header files here. 1343 </dd> 1344 1345 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt> 1346 <dd>This directory contains header files configured by the <tt>configure</tt> 1347 script. They wrap "standard" UNIX and C header files. Source code can 1348 include these header files which automatically take care of the conditional 1349 #includes that the <tt>configure</tt> script generates.</dd> 1350 </dl> 1351 </div> 1352 1353 <!-- ======================================================================= --> 1354 <h3> 1355 <a name="lib"><tt>llvm/lib</tt></a> 1356 </h3> 1357 1358 <div> 1359 1360 <p>This directory contains most of the source files of the LLVM system. In LLVM, 1361 almost all code exists in libraries, making it very easy to share code among the 1362 different <a href="#tools">tools</a>.</p> 1363 1364 <dl> 1365 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt> 1366 <dd> This directory holds the core LLVM source files that implement core 1367 classes like Instruction and BasicBlock.</dd> 1368 1369 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt> 1370 <dd>This directory holds the source code for the LLVM assembly language parser 1371 library.</dd> 1372 1373 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt> 1374 <dd>This directory holds code for reading and write LLVM bitcode.</dd> 1375 1376 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of 1377 different program analyses, such as Dominator Information, Call Graphs, 1378 Induction Variables, Interval Identification, Natural Loop Identification, 1379 etc.</dd> 1380 1381 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt> 1382 <dd> This directory contains the source code for the LLVM to LLVM program 1383 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional 1384 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global 1385 Elimination, and many others.</dd> 1386 1387 <dt><tt><b>llvm/lib/Target/</b></tt></dt> 1388 <dd> This directory contains files that describe various target architectures 1389 for code generation. For example, the <tt>llvm/lib/Target/X86</tt> 1390 directory holds the X86 machine description while 1391 <tt>llvm/lib/Target/ARM</tt> implements the ARM backend.</dd> 1392 1393 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt> 1394 <dd> This directory contains the major parts of the code generator: Instruction 1395 Selector, Instruction Scheduling, and Register Allocation.</dd> 1396 1397 <dt><tt><b>llvm/lib/MC/</b></tt></dt> 1398 <dd>(FIXME: T.B.D.)</dd> 1399 1400 <!--FIXME: obsoleted --> 1401 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt> 1402 <dd> This directory contains the source level debugger library that makes 1403 it possible to instrument LLVM programs so that a debugger could identify 1404 source code locations at which the program is executing.</dd> 1405 1406 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt> 1407 <dd> This directory contains libraries for executing LLVM bitcode directly 1408 at runtime in both interpreted and JIT compiled fashions.</dd> 1409 1410 <dt><tt><b>llvm/lib/Support/</b></tt></dt> 1411 <dd> This directory contains the source code that corresponds to the header 1412 files located in <tt>llvm/include/ADT/</tt> 1413 and <tt>llvm/include/Support/</tt>.</dd> 1414 </dl> 1415 1416 </div> 1417 1418 <!-- ======================================================================= --> 1419 <h3> 1420 <a name="projects"><tt>llvm/projects</tt></a> 1421 </h3> 1422 1423 <div> 1424 <p>This directory contains projects that are not strictly part of LLVM but are 1425 shipped with LLVM. This is also the directory where you should create your own 1426 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how 1427 to set up your own project.</p> 1428 </div> 1429 1430 <!-- ======================================================================= --> 1431 <h3> 1432 <a name="runtime"><tt>llvm/runtime</tt></a> 1433 </h3> 1434 1435 <div> 1436 1437 <p>This directory contains libraries which are compiled into LLVM bitcode and 1438 used when linking programs with the Clang front end. Most of these libraries are 1439 skeleton versions of real libraries; for example, libc is a stripped down 1440 version of glibc.</p> 1441 1442 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front 1443 end to compile.</p> 1444 1445 </div> 1446 1447 <!-- ======================================================================= --> 1448 <h3> 1449 <a name="test"><tt>llvm/test</tt></a> 1450 </h3> 1451 1452 <div> 1453 <p>This directory contains feature and regression tests and other basic sanity 1454 checks on the LLVM infrastructure. These are intended to run quickly and cover 1455 a lot of territory without being exhaustive.</p> 1456 </div> 1457 1458 <!-- ======================================================================= --> 1459 <h3> 1460 <a name="test-suite"><tt>test-suite</tt></a> 1461 </h3> 1462 1463 <div> 1464 <p>This is not a directory in the normal llvm module; it is a separate 1465 Subversion 1466 module that must be checked out (usually to <tt>projects/test-suite</tt>). 1467 This 1468 module contains a comprehensive correctness, performance, and benchmarking 1469 test 1470 suite for LLVM. It is a separate Subversion module because not every LLVM 1471 user is 1472 interested in downloading or building such a comprehensive test suite. For 1473 further details on this test suite, please see the 1474 <a href="TestingGuide.html">Testing Guide</a> document.</p> 1475 </div> 1476 1477 <!-- ======================================================================= --> 1478 <h3> 1479 <a name="tools"><tt>llvm/tools</tt></a> 1480 </h3> 1481 1482 <div> 1483 1484 <p>The <b>tools</b> directory contains the executables built out of the 1485 libraries above, which form the main part of the user interface. You can 1486 always get help for a tool by typing <tt>tool_name -help</tt>. The 1487 following is a brief introduction to the most important tools. More detailed 1488 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p> 1489 1490 <dl> 1491 1492 <dt><tt><b>bugpoint</b></tt></dt> 1493 <dd><tt>bugpoint</tt> is used to debug 1494 optimization passes or code generation backends by narrowing down the 1495 given test case to the minimum number of passes and/or instructions that 1496 still cause a problem, whether it is a crash or miscompilation. See <a 1497 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information 1498 on using <tt>bugpoint</tt>.</dd> 1499 1500 <dt><tt><b>llvm-ar</b></tt></dt> 1501 <dd>The archiver produces an archive containing 1502 the given LLVM bitcode files, optionally with an index for faster 1503 lookup.</dd> 1504 1505 <dt><tt><b>llvm-as</b></tt></dt> 1506 <dd>The assembler transforms the human readable LLVM assembly to LLVM 1507 bitcode.</dd> 1508 1509 <dt><tt><b>llvm-dis</b></tt></dt> 1510 <dd>The disassembler transforms the LLVM bitcode to human readable 1511 LLVM assembly.</dd> 1512 1513 <dt><tt><b>llvm-ld</b></tt></dt> 1514 <dd><tt>llvm-ld</tt> is a general purpose and extensible linker for LLVM. 1515 It performs standard link time optimizations and allows optimization 1516 modules to be loaded and run so that language specific optimizations can 1517 be applied at link time.</dd> 1518 1519 <dt><tt><b>llvm-link</b></tt></dt> 1520 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into 1521 a single program.</dd> 1522 1523 <dt><tt><b>lli</b></tt></dt> 1524 <dd><tt>lli</tt> is the LLVM interpreter, which 1525 can directly execute LLVM bitcode (although very slowly...). For architectures 1526 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt> 1527 will function as a Just-In-Time compiler (if the functionality was compiled 1528 in), and will execute the code <i>much</i> faster than the interpreter.</dd> 1529 1530 <dt><tt><b>llc</b></tt></dt> 1531 <dd> <tt>llc</tt> is the LLVM backend compiler, which 1532 translates LLVM bitcode to a native code assembly file or to C code (with 1533 the -march=c option).</dd> 1534 1535 <dt><tt><b>llvm-gcc</b></tt></dt> 1536 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to 1537 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM 1538 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the 1539 usual machine code output. It works just like any other GCC compiler, 1540 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used. 1541 Additionally, the the source code for <tt>llvm-gcc</tt> is available as a 1542 separate Subversion module.</dd> 1543 1544 <dt><tt><b>opt</b></tt></dt> 1545 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM 1546 transformations (which are specified on the command line), and then outputs 1547 the resultant bitcode. The '<tt>opt -help</tt>' command is a good way to 1548 get a list of the program transformations available in LLVM.<br> 1549 <dd><tt>opt</tt> can also be used to run a specific analysis on an input 1550 LLVM bitcode file and print out the results. It is primarily useful for 1551 debugging analyses, or familiarizing yourself with what an analysis does.</dd> 1552 </dl> 1553 </div> 1554 1555 <!-- ======================================================================= --> 1556 <h3> 1557 <a name="utils"><tt>llvm/utils</tt></a> 1558 </h3> 1559 1560 <div> 1561 1562 <p>This directory contains utilities for working with LLVM source code, and some 1563 of the utilities are actually required as part of the build process because they 1564 are code generators for parts of LLVM infrastructure.</p> 1565 1566 <dl> 1567 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script 1568 that finds differences between code that LLC generates and code that LLI 1569 generates. This is a useful tool if you are debugging one of them, 1570 assuming that the other generates correct output. For the full user 1571 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br> 1572 1573 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains 1574 syntax-highlighting files which will work with Emacs and XEmacs editors, 1575 providing syntax highlighting support for LLVM assembly files and TableGen 1576 description files. For information on how to use the syntax files, consult 1577 the <tt>README</tt> file in that directory.<br><br> 1578 1579 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds 1580 and outputs all non-generated source files, which is useful if one wishes 1581 to do a lot of development across directories and does not want to 1582 individually find each file. One way to use it is to run, for example: 1583 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source 1584 tree.<br><br> 1585 1586 <dt><tt><b>llvmgrep</b></tt></dt> 1587 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and 1588 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command 1589 line. This is a very efficient way of searching the source base for a 1590 particular regular expression.</dd> 1591 1592 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all 1593 files in the current directory and then compiles and links the tool that 1594 is the first argument. For example, assuming you are in the directory 1595 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path, 1596 simply running <tt>makellvm llc</tt> will make a build of the current 1597 directory, switch to directory <tt>llvm/tools/llc</tt> and build it, 1598 causing a re-linking of LLC.<br><br> 1599 1600 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains 1601 the tool used to generate register descriptions, instruction set 1602 descriptions, and even assemblers from common TableGen description 1603 files.<br><br> 1604 1605 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains 1606 syntax-highlighting files which will work with the VIM editor, providing 1607 syntax highlighting support for LLVM assembly files and TableGen 1608 description files. For information on how to use the syntax files, consult 1609 the <tt>README</tt> file in that directory.<br><br> 1610 1611 </dl> 1612 1613 </div> 1614 1615 </div> 1616 1617 <!-- *********************************************************************** --> 1618 <h2> 1619 <a name="tutorial">An Example Using the LLVM Tool Chain</a> 1620 </h2> 1621 <!-- *********************************************************************** --> 1622 1623 <div> 1624 <p>This section gives an example of using LLVM with the Clang front end.</p> 1625 1626 <!-- ======================================================================= --> 1627 <h3> 1628 <a name="tutorial4">Example with clang</a> 1629 </h3> 1630 1631 <div> 1632 1633 <ol> 1634 <li><p>First, create a simple C file, name it 'hello.c':</p> 1635 1636 <div class="doc_code"> 1637 <pre> 1638 #include <stdio.h> 1639 1640 int main() { 1641 printf("hello world\n"); 1642 return 0; 1643 } 1644 </pre></div></li> 1645 1646 <li><p>Next, compile the C file into a native executable:</p> 1647 1648 <div class="doc_code"><pre>% clang hello.c -o hello</pre></div> 1649 1650 <p>Note that clang works just like GCC by default. The standard -S and 1651 -c arguments work as usual (producing a native .s or .o file, 1652 respectively).</p></li> 1653 1654 <li><p>Next, compile the C file into a LLVM bitcode file:</p> 1655 1656 <div class="doc_code"> 1657 <pre>% clang -O3 -emit-llvm hello.c -c -o hello.bc</pre></div> 1658 1659 <p>The -emit-llvm option can be used with the -S or -c options to emit an 1660 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you 1661 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on 1662 the bitcode file.</p></li> 1663 1664 <li><p>Run the program in both forms. To run the program, use:</p> 1665 1666 <div class="doc_code"><pre>% ./hello</pre></div> 1667 1668 <p>and</p> 1669 1670 <div class="doc_code"><pre>% lli hello.bc</pre></div> 1671 1672 <p>The second examples shows how to invoke the LLVM JIT, <a 1673 href="CommandGuide/html/lli.html">lli</a>.</p></li> 1674 1675 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly 1676 code:</p> 1677 1678 <div class="doc_code"> 1679 <pre>llvm-dis < hello.bc | less</pre> 1680 </div></li> 1681 1682 <li><p>Compile the program to native assembly using the LLC code 1683 generator:</p> 1684 1685 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li> 1686 1687 <li><p>Assemble the native assembly language file into a program:</p> 1688 1689 <div class="doc_code"> 1690 <pre> 1691 <b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native 1692 1693 <b>Others:</b> % gcc hello.s -o hello.native 1694 </pre> 1695 </div></li> 1696 1697 <li><p>Execute the native code program:</p> 1698 1699 <div class="doc_code"><pre>% ./hello.native</pre></div> 1700 1701 <p>Note that using clang to compile directly to native code (i.e. when 1702 the -emit-llvm option is not present) does steps 6/7/8 for you.</p> 1703 </li> 1704 1705 </ol> 1706 1707 </div> 1708 1709 </div> 1710 1711 <!-- *********************************************************************** --> 1712 <h2> 1713 <a name="problems">Common Problems</a> 1714 </h2> 1715 <!-- *********************************************************************** --> 1716 1717 <div> 1718 1719 <p>If you are having problems building or using LLVM, or if you have any other 1720 general questions about LLVM, please consult the <a href="FAQ.html">Frequently 1721 Asked Questions</a> page.</p> 1722 1723 </div> 1724 1725 <!-- *********************************************************************** --> 1726 <h2> 1727 <a name="links">Links</a> 1728 </h2> 1729 <!-- *********************************************************************** --> 1730 1731 <div> 1732 1733 <p>This document is just an <b>introduction</b> on how to use LLVM to do 1734 some simple things... there are many more interesting and complicated things 1735 that you can do that aren't documented here (but we'll gladly accept a patch 1736 if you want to write something up!). For more information about LLVM, check 1737 out:</p> 1738 1739 <ul> 1740 <li><a href="http://llvm.org/">LLVM homepage</a></li> 1741 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li> 1742 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project 1743 that Uses LLVM</a></li> 1744 </ul> 1745 1746 </div> 1747 1748 <!-- *********************************************************************** --> 1749 1750 <hr> 1751 <address> 1752 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img 1753 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a> 1754 <a href="http://validator.w3.org/check/referer"><img 1755 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a> 1756 1757 <a href="mailto:sabre (a] nondot.org">Chris Lattner</a><br> 1758 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br> 1759 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br> 1760 Last modified: $Date$ 1761 </address> 1762 </body> 1763 </html> 1764
