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="_static/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>SUSE 11 GCC 4.3.4</b>: Miscompiles LLVM, causing crashes in ValueHandle logic.</p> 594 <p><b>GCC 4.3.5 and GCC 4.4.5 on ARM</b>: These can miscompile <tt>value >> 595 1</tt> even at -O0. A test failure in <tt>test/Assembler/alignstack.ll</tt> is 596 one symptom of the problem. 597 <p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very 598 long warning messages complaining that some ".gnu.linkonce.t.*" symbol was 599 defined in a discarded section. You can safely ignore these messages as they are 600 erroneous and the linkage is correct. These messages disappear using ld 601 2.17.</p> 602 603 <p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a 604 href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which 605 causes huge link times (minutes instead of seconds) when building LLVM. We 606 recommend upgrading to a newer version (2.17.50.0.4 or later).</p> 607 608 <p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained 609 <a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a> 610 which causes intermittent failures when building LLVM with position independent 611 code. The symptom is an error about cyclic dependencies. We recommend 612 upgrading to a newer version of Gold.</p> 613 614 </div> 615 616 </div> 617 618 <!-- *********************************************************************** --> 619 <h2> 620 <a name="starting">Getting Started with LLVM</a> 621 </h2> 622 <!-- *********************************************************************** --> 623 624 <div> 625 626 <p>The remainder of this guide is meant to get you up and running with 627 LLVM and to give you some basic information about the LLVM environment.</p> 628 629 <p>The later sections of this guide describe the <a 630 href="#layout">general layout</a> of the LLVM source tree, a <a 631 href="#tutorial">simple example</a> using the LLVM tool chain, and <a 632 href="#links">links</a> to find more information about LLVM or to get 633 help via e-mail.</p> 634 635 <!-- ======================================================================= --> 636 <h3> 637 <a name="terminology">Terminology and Notation</a> 638 </h3> 639 640 <div> 641 642 <p>Throughout this manual, the following names are used to denote paths 643 specific to the local system and working environment. <i>These are not 644 environment variables you need to set but just strings used in the rest 645 of this document below</i>. In any of the examples below, simply replace 646 each of these names with the appropriate pathname on your local system. 647 All these paths are absolute:</p> 648 649 <dl> 650 <dt>SRC_ROOT 651 <dd> 652 This is the top level directory of the LLVM source tree. 653 <br><br> 654 655 <dt>OBJ_ROOT 656 <dd> 657 This is the top level directory of the LLVM object tree (i.e. the 658 tree where object files and compiled programs will be placed. It 659 can be the same as SRC_ROOT). 660 <br><br> 661 662 </dl> 663 664 </div> 665 666 <!-- ======================================================================= --> 667 <h3> 668 <a name="environment">Setting Up Your Environment</a> 669 </h3> 670 671 <div> 672 673 <p> 674 In order to compile and use LLVM, you may need to set some environment 675 variables. 676 677 <dl> 678 <dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt> 679 <dd>[Optional] This environment variable helps LLVM linking tools find the 680 locations of your bitcode libraries. It is provided only as a 681 convenience since you can specify the paths using the -L options of the 682 tools and the C/C++ front-end will automatically use the bitcode files 683 installed in its 684 <tt>lib</tt> directory.</dd> 685 </dl> 686 687 </div> 688 689 <!-- ======================================================================= --> 690 <h3> 691 <a name="unpack">Unpacking the LLVM Archives</a> 692 </h3> 693 694 <div> 695 696 <p> 697 If you have the LLVM distribution, you will need to unpack it before you 698 can begin to compile it. LLVM is distributed as a set of two files: the LLVM 699 suite and the LLVM GCC front end compiled for your platform. There is an 700 additional test suite that is optional. Each file is a TAR archive that is 701 compressed with the gzip program. 702 </p> 703 704 <p>The files are as follows, with <em>x.y</em> marking the version number: 705 <dl> 706 <dt><tt>llvm-x.y.tar.gz</tt></dt> 707 <dd>Source release for the LLVM libraries and tools.<br></dd> 708 709 <dt><tt>llvm-test-x.y.tar.gz</tt></dt> 710 <dd>Source release for the LLVM test-suite.</dd> 711 712 <dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt> 713 <dd>Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root 714 directory for build instructions.<br></dd> 715 716 <dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt> 717 <dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd> 718 719 </dl> 720 721 </div> 722 723 <!-- ======================================================================= --> 724 <h3> 725 <a name="checkout">Checkout LLVM from Subversion</a> 726 </h3> 727 728 <div> 729 730 <p>If you have access to our Subversion repository, you can get a fresh copy of 731 the entire source code. All you need to do is check it out from Subversion as 732 follows:</p> 733 734 <ul> 735 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li> 736 <li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li> 737 <li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk 738 llvm</tt></li> 739 </ul> 740 741 742 <p>This will create an '<tt>llvm</tt>' directory in the current 743 directory and fully populate it with the LLVM source code, Makefiles, 744 test directories, and local copies of documentation files.</p> 745 746 <p>If you want to get a specific release (as opposed to the most recent 747 revision), you can checkout it from the '<tt>tags</tt>' directory (instead of 748 '<tt>trunk</tt>'). The following releases are located in the following 749 subdirectories of the '<tt>tags</tt>' directory:</p> 750 751 <ul> 752 <li>Release 3.1: <b>RELEASE_31/final</b></li> 753 <li>Release 3.0: <b>RELEASE_30/final</b></li> 754 <li>Release 2.9: <b>RELEASE_29/final</b></li> 755 <li>Release 2.8: <b>RELEASE_28</b></li> 756 <li>Release 2.7: <b>RELEASE_27</b></li> 757 <li>Release 2.6: <b>RELEASE_26</b></li> 758 <li>Release 2.5: <b>RELEASE_25</b></li> 759 <li>Release 2.4: <b>RELEASE_24</b></li> 760 <li>Release 2.3: <b>RELEASE_23</b></li> 761 <li>Release 2.2: <b>RELEASE_22</b></li> 762 <li>Release 2.1: <b>RELEASE_21</b></li> 763 <li>Release 2.0: <b>RELEASE_20</b></li> 764 <li>Release 1.9: <b>RELEASE_19</b></li> 765 <li>Release 1.8: <b>RELEASE_18</b></li> 766 <li>Release 1.7: <b>RELEASE_17</b></li> 767 <li>Release 1.6: <b>RELEASE_16</b></li> 768 <li>Release 1.5: <b>RELEASE_15</b></li> 769 <li>Release 1.4: <b>RELEASE_14</b></li> 770 <li>Release 1.3: <b>RELEASE_13</b></li> 771 <li>Release 1.2: <b>RELEASE_12</b></li> 772 <li>Release 1.1: <b>RELEASE_11</b></li> 773 <li>Release 1.0: <b>RELEASE_1</b></li> 774 </ul> 775 776 <p>If you would like to get the LLVM test suite (a separate package as of 1.4), 777 you get it from the Subversion repository:</p> 778 779 <div class="doc_code"> 780 <pre> 781 % cd llvm/projects 782 % svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite 783 </pre> 784 </div> 785 786 <p>By placing it in the <tt>llvm/projects</tt>, it will be automatically 787 configured by the LLVM configure script as well as automatically updated when 788 you run <tt>svn update</tt>.</p> 789 790 </div> 791 792 <!-- ======================================================================= --> 793 <h3> 794 <a name="git_mirror">GIT mirror</a> 795 </h3> 796 797 <div> 798 799 <p>GIT mirrors are available for a number of LLVM subprojects. These mirrors 800 sync automatically with each Subversion commit and contain all necessary 801 git-svn marks (so, you can recreate git-svn metadata locally). Note that right 802 now mirrors reflect only <tt>trunk</tt> for each project. You can do the 803 read-only GIT clone of LLVM via:</p> 804 805 <pre class="doc_code"> 806 git clone http://llvm.org/git/llvm.git 807 </pre> 808 809 <p>If you want to check out clang too, run:</p> 810 811 <pre class="doc_code"> 812 git clone http://llvm.org/git/llvm.git 813 cd llvm/tools 814 git clone http://llvm.org/git/clang.git 815 </pre> 816 817 <p> 818 Since the upstream repository is in Subversion, you should use 819 <tt>"git pull --rebase"</tt> 820 instead of <tt>"git pull"</tt> to avoid generating a non-linear 821 history in your clone. 822 To configure <tt>"git pull"</tt> to pass <tt>--rebase</tt> by default 823 on the master branch, run the following command: 824 </p> 825 826 <pre class="doc_code"> 827 git config branch.master.rebase true 828 </pre> 829 830 <h4>Sending patches with Git</h4> 831 <div> 832 <p> 833 Please read <a href="DeveloperPolicy.html#patches">Developer Policy</a>, too. 834 </p> 835 836 <p> 837 Assume <tt>master</tt> points the upstream and <tt>mybranch</tt> points your 838 working branch, and <tt>mybranch</tt> is rebased onto <tt>master</tt>. 839 At first you may check sanity of whitespaces: 840 </p> 841 842 <pre class="doc_code"> 843 git diff --check master..mybranch 844 </pre> 845 846 <p> 847 The easiest way to generate a patch is as below: 848 </p> 849 850 <pre class="doc_code"> 851 git diff master..mybranch > /path/to/mybranch.diff 852 </pre> 853 854 <p> 855 It is a little different from svn-generated diff. git-diff-generated diff has 856 prefixes like <tt>a/</tt> and <tt>b/</tt>. Don't worry, most developers might 857 know it could be accepted with <tt>patch -p1 -N</tt>. 858 </p> 859 860 <p> 861 But you may generate patchset with git-format-patch. It generates 862 by-each-commit patchset. To generate patch files to attach to your article: 863 </p> 864 865 <pre class="doc_code"> 866 git format-patch --no-attach master..mybranch -o /path/to/your/patchset 867 </pre> 868 869 <p> 870 If you would like to send patches directly, you may use git-send-email or 871 git-imap-send. Here is an example to generate the patchset in Gmail's [Drafts]. 872 </p> 873 874 <pre class="doc_code"> 875 git format-patch --attach master..mybranch --stdout | git imap-send 876 </pre> 877 878 <p> 879 Then, your .git/config should have [imap] sections. 880 </p> 881 882 <pre class="doc_code"> 883 [imap] 884 host = imaps://imap.gmail.com 885 user = <em>your.gmail.account</em>@gmail.com 886 pass = <em>himitsu!</em> 887 port = 993 888 sslverify = false 889 ; in English 890 folder = "[Gmail]/Drafts" 891 ; example for Japanese, "Modified UTF-7" encoded. 892 folder = "[Gmail]/&Tgtm+DBN-" 893 ; example for Traditional Chinese 894 folder = "[Gmail]/&g0l6Pw-" 895 </pre> 896 897 </div> 898 899 <h4>For developers to work with git-svn</h4> 900 <div> 901 902 <p>To set up clone from which you can submit code using 903 <tt>git-svn</tt>, run:</p> 904 905 <pre class="doc_code"> 906 git clone http://llvm.org/git/llvm.git 907 cd llvm 908 git svn init https://llvm.org/svn/llvm-project/llvm/trunk --username=<username> 909 git config svn-remote.svn.fetch :refs/remotes/origin/master 910 git svn rebase -l # -l avoids fetching ahead of the git mirror. 911 912 # If you have clang too: 913 cd tools 914 git clone http://llvm.org/git/clang.git 915 cd clang 916 git svn init https://llvm.org/svn/llvm-project/cfe/trunk --username=<username> 917 git config svn-remote.svn.fetch :refs/remotes/origin/master 918 git svn rebase -l 919 </pre> 920 921 <p>To update this clone without generating git-svn tags that conflict 922 with the upstream git repo, run:</p> 923 924 <pre class="doc_code"> 925 git fetch && (cd tools/clang && git fetch) # Get matching revisions of both trees. 926 git checkout master 927 git svn rebase -l 928 (cd tools/clang && 929 git checkout master && 930 git svn rebase -l) 931 </pre> 932 933 <p>This leaves your working directories on their master branches, so 934 you'll need to <tt>checkout</tt> each working branch individually and 935 <tt>rebase</tt> it on top of its parent branch. (Note: This script is 936 intended for relative newbies to git. If you have more experience, 937 you can likely improve on it.)</p> 938 939 <p>The git-svn metadata can get out of sync after you mess around with 940 branches and <code>dcommit</code>. When that happens, <code>git svn 941 dcommit</code> stops working, complaining about files with uncommitted 942 changes. The fix is to rebuild the metadata:</p> 943 944 <pre class="doc_code"> 945 rm -rf .git/svn 946 git svn rebase -l 947 </pre> 948 949 </div> 950 951 </div> 952 953 <!-- ======================================================================= --> 954 <h3> 955 <a name="config">Local LLVM Configuration</a> 956 </h3> 957 958 <div> 959 960 <p>Once checked out from the Subversion repository, the LLVM suite source 961 code must be 962 configured via the <tt>configure</tt> script. This script sets variables in the 963 various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and 964 <tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with 965 the Makefiles needed to begin building LLVM.</p> 966 967 <p>The following environment variables are used by the <tt>configure</tt> 968 script to configure the build system:</p> 969 970 <table summary="LLVM configure script environment variables"> 971 <tr><th>Variable</th><th>Purpose</th></tr> 972 <tr> 973 <td>CC</td> 974 <td>Tells <tt>configure</tt> which C compiler to use. By default, 975 <tt>configure</tt> will look for the first GCC C compiler in 976 <tt>PATH</tt>. Use this variable to override 977 <tt>configure</tt>'s default behavior.</td> 978 </tr> 979 <tr> 980 <td>CXX</td> 981 <td>Tells <tt>configure</tt> which C++ compiler to use. By default, 982 <tt>configure</tt> will look for the first GCC C++ compiler in 983 <tt>PATH</tt>. Use this variable to override 984 <tt>configure</tt>'s default behavior.</td> 985 </tr> 986 </table> 987 988 <p>The following options can be used to set or enable LLVM specific options:</p> 989 990 <dl> 991 <dt><i>--enable-optimized</i></dt> 992 <dd> 993 Enables optimized compilation (debugging symbols are removed 994 and GCC optimization flags are enabled). Note that this is the default 995 setting if you are using the LLVM distribution. The default behavior 996 of an Subversion checkout is to use an unoptimized build (also known as a 997 debug build). 998 <br><br> 999 </dd> 1000 <dt><i>--enable-debug-runtime</i></dt> 1001 <dd> 1002 Enables debug symbols in the runtime libraries. The default is to strip 1003 debug symbols from the runtime libraries. 1004 </dd> 1005 <dt><i>--enable-jit</i></dt> 1006 <dd> 1007 Compile the Just In Time (JIT) compiler functionality. This is not 1008 available 1009 on all platforms. The default is dependent on platform, so it is best 1010 to explicitly enable it if you want it. 1011 <br><br> 1012 </dd> 1013 <dt><i>--enable-targets=</i><tt>target-option</tt></dt> 1014 <dd>Controls which targets will be built and linked into llc. The default 1015 value for <tt>target_options</tt> is "all" which builds and links all 1016 available targets. The value "host-only" can be specified to build only a 1017 native compiler (no cross-compiler targets available). The "native" target is 1018 selected as the target of the build host. You can also specify a comma 1019 separated list of target names that you want available in llc. The target 1020 names use all lower case. The current set of targets is: <br> 1021 <tt>arm, cpp, hexagon, mblaze, mips, mipsel, msp430, powerpc, ptx, sparc, spu, x86, x86_64, xcore</tt>. 1022 <br><br></dd> 1023 <dt><i>--enable-doxygen</i></dt> 1024 <dd>Look for the doxygen program and enable construction of doxygen based 1025 documentation from the source code. This is disabled by default because 1026 generating the documentation can take a long time and producess 100s of 1027 megabytes of output.</dd> 1028 <dt><i>--with-udis86</i></dt> 1029 <dd>LLVM can use external disassembler library for various purposes (now it's 1030 used only for examining code produced by JIT). This option will enable usage 1031 of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64 1032 bits) disassembler library.</dd> 1033 </dl> 1034 1035 <p>To configure LLVM, follow these steps:</p> 1036 1037 <ol> 1038 <li><p>Change directory into the object root directory:</p> 1039 1040 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li> 1041 1042 <li><p>Run the <tt>configure</tt> script located in the LLVM source 1043 tree:</p> 1044 1045 <div class="doc_code"> 1046 <pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre> 1047 </div></li> 1048 </ol> 1049 1050 </div> 1051 1052 <!-- ======================================================================= --> 1053 <h3> 1054 <a name="compile">Compiling the LLVM Suite Source Code</a> 1055 </h3> 1056 1057 <div> 1058 1059 <p>Once you have configured LLVM, you can build it. There are three types of 1060 builds:</p> 1061 1062 <dl> 1063 <dt>Debug Builds 1064 <dd> 1065 These builds are the default when one is using an Subversion checkout and 1066 types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was 1067 used during configuration). The build system will compile the tools and 1068 libraries with debugging information. To get a Debug Build using the 1069 LLVM distribution the <tt>--disable-optimized</tt> option must be passed 1070 to <tt>configure</tt>. 1071 <br><br> 1072 1073 <dt>Release (Optimized) Builds 1074 <dd> 1075 These builds are enabled with the <tt>--enable-optimized</tt> option to 1076 <tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the 1077 <tt>gmake</tt> command line. For these builds, the build system will 1078 compile the tools and libraries with GCC optimizations enabled and strip 1079 debugging information from the libraries and executables it generates. 1080 Note that Release Builds are default when using an LLVM distribution. 1081 <br><br> 1082 1083 <dt>Profile Builds 1084 <dd> 1085 These builds are for use with profiling. They compile profiling 1086 information into the code for use with programs like <tt>gprof</tt>. 1087 Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt> 1088 on the <tt>gmake</tt> command line. 1089 </dl> 1090 1091 <p>Once you have LLVM configured, you can build it by entering the 1092 <i>OBJ_ROOT</i> directory and issuing the following command:</p> 1093 1094 <div class="doc_code"><pre>% gmake</pre></div> 1095 1096 <p>If the build fails, please <a href="#brokengcc">check here</a> to see if you 1097 are using a version of GCC that is known not to compile LLVM.</p> 1098 1099 <p> 1100 If you have multiple processors in your machine, you may wish to use some of 1101 the parallel build options provided by GNU Make. For example, you could use the 1102 command:</p> 1103 1104 <div class="doc_code"><pre>% gmake -j2</pre></div> 1105 1106 <p>There are several special targets which are useful when working with the LLVM 1107 source code:</p> 1108 1109 <dl> 1110 <dt><tt>gmake clean</tt> 1111 <dd> 1112 Removes all files generated by the build. This includes object files, 1113 generated C/C++ files, libraries, and executables. 1114 <br><br> 1115 1116 <dt><tt>gmake dist-clean</tt> 1117 <dd> 1118 Removes everything that <tt>gmake clean</tt> does, but also removes files 1119 generated by <tt>configure</tt>. It attempts to return the source tree to the 1120 original state in which it was shipped. 1121 <br><br> 1122 1123 <dt><tt>gmake install</tt> 1124 <dd> 1125 Installs LLVM header files, libraries, tools, and documentation in a 1126 hierarchy 1127 under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which 1128 defaults to <tt>/usr/local</tt>. 1129 <br><br> 1130 1131 <dt><tt>gmake -C runtime install-bytecode</tt> 1132 <dd> 1133 Assuming you built LLVM into $OBJDIR, when this command is run, it will 1134 install bitcode libraries into the GCC front end's bitcode library 1135 directory. If you need to update your bitcode libraries, 1136 this is the target to use once you've built them. 1137 <br><br> 1138 </dl> 1139 1140 <p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further 1141 details on these <tt>make</tt> targets and descriptions of other targets 1142 available.</p> 1143 1144 <p>It is also possible to override default values from <tt>configure</tt> by 1145 declaring variables on the command line. The following are some examples:</p> 1146 1147 <dl> 1148 <dt><tt>gmake ENABLE_OPTIMIZED=1</tt> 1149 <dd> 1150 Perform a Release (Optimized) build. 1151 <br><br> 1152 1153 <dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt> 1154 <dd> 1155 Perform a Release (Optimized) build without assertions enabled. 1156 <br><br> 1157 1158 <dt><tt>gmake ENABLE_OPTIMIZED=0</tt> 1159 <dd> 1160 Perform a Debug build. 1161 <br><br> 1162 1163 <dt><tt>gmake ENABLE_PROFILING=1</tt> 1164 <dd> 1165 Perform a Profiling build. 1166 <br><br> 1167 1168 <dt><tt>gmake VERBOSE=1</tt> 1169 <dd> 1170 Print what <tt>gmake</tt> is doing on standard output. 1171 <br><br> 1172 1173 <dt><tt>gmake TOOL_VERBOSE=1</tt></dt> 1174 <dd>Ask each tool invoked by the makefiles to print out what it is doing on 1175 the standard output. This also implies <tt>VERBOSE=1</tt>. 1176 <br><br></dd> 1177 </dl> 1178 1179 <p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build 1180 it and any subdirectories that it contains. Entering any directory inside the 1181 LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below 1182 that directory that is out of date.</p> 1183 1184 </div> 1185 1186 <!-- ======================================================================= --> 1187 <h3> 1188 <a name="cross-compile">Cross-Compiling LLVM</a> 1189 </h3> 1190 1191 <div> 1192 <p>It is possible to cross-compile LLVM itself. That is, you can create LLVM 1193 executables and libraries to be hosted on a platform different from the 1194 platform where they are build (a Canadian Cross build). To configure a 1195 cross-compile, supply the configure script with <tt>--build</tt> and 1196 <tt>--host</tt> options that are different. The values of these options must 1197 be legal target triples that your GCC compiler supports.</p> 1198 1199 <p>The result of such a build is executables that are not runnable on 1200 on the build host (--build option) but can be executed on the compile host 1201 (--host option).</p> 1202 </div> 1203 1204 <!-- ======================================================================= --> 1205 <h3> 1206 <a name="objfiles">The Location of LLVM Object Files</a> 1207 </h3> 1208 1209 <div> 1210 1211 <p>The LLVM build system is capable of sharing a single LLVM source tree among 1212 several LLVM builds. Hence, it is possible to build LLVM for several different 1213 platforms or configurations using the same source tree.</p> 1214 1215 <p>This is accomplished in the typical autoconf manner:</p> 1216 1217 <ul> 1218 <li><p>Change directory to where the LLVM object files should live:</p> 1219 1220 <div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li> 1221 1222 <li><p>Run the <tt>configure</tt> script found in the LLVM source 1223 directory:</p> 1224 1225 <div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li> 1226 </ul> 1227 1228 <p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories 1229 named after the build type:</p> 1230 1231 <dl> 1232 <dt>Debug Builds with assertions enabled (the default) 1233 <dd> 1234 <dl> 1235 <dt>Tools 1236 <dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/bin</tt> 1237 <dt>Libraries 1238 <dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/lib</tt> 1239 </dl> 1240 <br><br> 1241 1242 <dt>Release Builds 1243 <dd> 1244 <dl> 1245 <dt>Tools 1246 <dd><tt><i>OBJ_ROOT</i>/Release/bin</tt> 1247 <dt>Libraries 1248 <dd><tt><i>OBJ_ROOT</i>/Release/lib</tt> 1249 </dl> 1250 <br><br> 1251 1252 <dt>Profile Builds 1253 <dd> 1254 <dl> 1255 <dt>Tools 1256 <dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt> 1257 <dt>Libraries 1258 <dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt> 1259 </dl> 1260 </dl> 1261 1262 </div> 1263 1264 <!-- ======================================================================= --> 1265 <h3> 1266 <a name="optionalconfig">Optional Configuration Items</a> 1267 </h3> 1268 1269 <div> 1270 1271 <p> 1272 If you're running on a Linux system that supports the "<a 1273 href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>" 1274 module, and you have root access on the system, you can set your system up to 1275 execute LLVM bitcode files directly. To do this, use commands like this (the 1276 first command may not be required if you are already using the module):</p> 1277 1278 <div class="doc_code"> 1279 <pre> 1280 $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc 1281 $ echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register 1282 $ chmod u+x hello.bc (if needed) 1283 $ ./hello.bc 1284 </pre> 1285 </div> 1286 1287 <p> 1288 This allows you to execute LLVM bitcode files directly. On Debian, you 1289 can also use this command instead of the 'echo' command above: 1290 </p> 1291 1292 <div class="doc_code"> 1293 <pre> 1294 $ sudo update-binfmts --install llvm /path/to/lli --magic 'BC' 1295 </pre> 1296 </div> 1297 1298 </div> 1299 1300 </div> 1301 1302 <!-- *********************************************************************** --> 1303 <h2> 1304 <a name="layout">Program Layout</a> 1305 </h2> 1306 <!-- *********************************************************************** --> 1307 1308 <div> 1309 1310 <p>One useful source of information about the LLVM source base is the LLVM <a 1311 href="http://www.doxygen.org/">doxygen</a> documentation available at <tt><a 1312 href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>. 1313 The following is a brief introduction to code layout:</p> 1314 1315 <!-- ======================================================================= --> 1316 <h3> 1317 <a name="examples"><tt>llvm/examples</tt></a> 1318 </h3> 1319 1320 <div> 1321 <p>This directory contains some simple examples of how to use the LLVM IR and 1322 JIT.</p> 1323 </div> 1324 1325 <!-- ======================================================================= --> 1326 <h3> 1327 <a name="include"><tt>llvm/include</tt></a> 1328 </h3> 1329 1330 <div> 1331 1332 <p>This directory contains public header files exported from the LLVM 1333 library. The three main subdirectories of this directory are:</p> 1334 1335 <dl> 1336 <dt><tt><b>llvm/include/llvm</b></tt></dt> 1337 <dd>This directory contains all of the LLVM specific header files. This 1338 directory also has subdirectories for different portions of LLVM: 1339 <tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>, 1340 etc...</dd> 1341 1342 <dt><tt><b>llvm/include/llvm/Support</b></tt></dt> 1343 <dd>This directory contains generic support libraries that are provided with 1344 LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities 1345 and a Command Line option processing library store their header files here. 1346 </dd> 1347 1348 <dt><tt><b>llvm/include/llvm/Config</b></tt></dt> 1349 <dd>This directory contains header files configured by the <tt>configure</tt> 1350 script. They wrap "standard" UNIX and C header files. Source code can 1351 include these header files which automatically take care of the conditional 1352 #includes that the <tt>configure</tt> script generates.</dd> 1353 </dl> 1354 </div> 1355 1356 <!-- ======================================================================= --> 1357 <h3> 1358 <a name="lib"><tt>llvm/lib</tt></a> 1359 </h3> 1360 1361 <div> 1362 1363 <p>This directory contains most of the source files of the LLVM system. In LLVM, 1364 almost all code exists in libraries, making it very easy to share code among the 1365 different <a href="#tools">tools</a>.</p> 1366 1367 <dl> 1368 <dt><tt><b>llvm/lib/VMCore/</b></tt></dt> 1369 <dd> This directory holds the core LLVM source files that implement core 1370 classes like Instruction and BasicBlock.</dd> 1371 1372 <dt><tt><b>llvm/lib/AsmParser/</b></tt></dt> 1373 <dd>This directory holds the source code for the LLVM assembly language parser 1374 library.</dd> 1375 1376 <dt><tt><b>llvm/lib/BitCode/</b></tt></dt> 1377 <dd>This directory holds code for reading and write LLVM bitcode.</dd> 1378 1379 <dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of 1380 different program analyses, such as Dominator Information, Call Graphs, 1381 Induction Variables, Interval Identification, Natural Loop Identification, 1382 etc.</dd> 1383 1384 <dt><tt><b>llvm/lib/Transforms/</b></tt></dt> 1385 <dd> This directory contains the source code for the LLVM to LLVM program 1386 transformations, such as Aggressive Dead Code Elimination, Sparse Conditional 1387 Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global 1388 Elimination, and many others.</dd> 1389 1390 <dt><tt><b>llvm/lib/Target/</b></tt></dt> 1391 <dd> This directory contains files that describe various target architectures 1392 for code generation. For example, the <tt>llvm/lib/Target/X86</tt> 1393 directory holds the X86 machine description while 1394 <tt>llvm/lib/Target/ARM</tt> implements the ARM backend.</dd> 1395 1396 <dt><tt><b>llvm/lib/CodeGen/</b></tt></dt> 1397 <dd> This directory contains the major parts of the code generator: Instruction 1398 Selector, Instruction Scheduling, and Register Allocation.</dd> 1399 1400 <dt><tt><b>llvm/lib/MC/</b></tt></dt> 1401 <dd>(FIXME: T.B.D.)</dd> 1402 1403 <!--FIXME: obsoleted --> 1404 <dt><tt><b>llvm/lib/Debugger/</b></tt></dt> 1405 <dd> This directory contains the source level debugger library that makes 1406 it possible to instrument LLVM programs so that a debugger could identify 1407 source code locations at which the program is executing.</dd> 1408 1409 <dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt> 1410 <dd> This directory contains libraries for executing LLVM bitcode directly 1411 at runtime in both interpreted and JIT compiled fashions.</dd> 1412 1413 <dt><tt><b>llvm/lib/Support/</b></tt></dt> 1414 <dd> This directory contains the source code that corresponds to the header 1415 files located in <tt>llvm/include/ADT/</tt> 1416 and <tt>llvm/include/Support/</tt>.</dd> 1417 </dl> 1418 1419 </div> 1420 1421 <!-- ======================================================================= --> 1422 <h3> 1423 <a name="projects"><tt>llvm/projects</tt></a> 1424 </h3> 1425 1426 <div> 1427 <p>This directory contains projects that are not strictly part of LLVM but are 1428 shipped with LLVM. This is also the directory where you should create your own 1429 LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how 1430 to set up your own project.</p> 1431 </div> 1432 1433 <!-- ======================================================================= --> 1434 <h3> 1435 <a name="runtime"><tt>llvm/runtime</tt></a> 1436 </h3> 1437 1438 <div> 1439 1440 <p>This directory contains libraries which are compiled into LLVM bitcode and 1441 used when linking programs with the Clang front end. Most of these libraries are 1442 skeleton versions of real libraries; for example, libc is a stripped down 1443 version of glibc.</p> 1444 1445 <p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front 1446 end to compile.</p> 1447 1448 </div> 1449 1450 <!-- ======================================================================= --> 1451 <h3> 1452 <a name="test"><tt>llvm/test</tt></a> 1453 </h3> 1454 1455 <div> 1456 <p>This directory contains feature and regression tests and other basic sanity 1457 checks on the LLVM infrastructure. These are intended to run quickly and cover 1458 a lot of territory without being exhaustive.</p> 1459 </div> 1460 1461 <!-- ======================================================================= --> 1462 <h3> 1463 <a name="test-suite"><tt>test-suite</tt></a> 1464 </h3> 1465 1466 <div> 1467 <p>This is not a directory in the normal llvm module; it is a separate 1468 Subversion 1469 module that must be checked out (usually to <tt>projects/test-suite</tt>). 1470 This 1471 module contains a comprehensive correctness, performance, and benchmarking 1472 test 1473 suite for LLVM. It is a separate Subversion module because not every LLVM 1474 user is 1475 interested in downloading or building such a comprehensive test suite. For 1476 further details on this test suite, please see the 1477 <a href="TestingGuide.html">Testing Guide</a> document.</p> 1478 </div> 1479 1480 <!-- ======================================================================= --> 1481 <h3> 1482 <a name="tools"><tt>llvm/tools</tt></a> 1483 </h3> 1484 1485 <div> 1486 1487 <p>The <b>tools</b> directory contains the executables built out of the 1488 libraries above, which form the main part of the user interface. You can 1489 always get help for a tool by typing <tt>tool_name -help</tt>. The 1490 following is a brief introduction to the most important tools. More detailed 1491 information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p> 1492 1493 <dl> 1494 1495 <dt><tt><b>bugpoint</b></tt></dt> 1496 <dd><tt>bugpoint</tt> is used to debug 1497 optimization passes or code generation backends by narrowing down the 1498 given test case to the minimum number of passes and/or instructions that 1499 still cause a problem, whether it is a crash or miscompilation. See <a 1500 href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information 1501 on using <tt>bugpoint</tt>.</dd> 1502 1503 <dt><tt><b>llvm-ar</b></tt></dt> 1504 <dd>The archiver produces an archive containing 1505 the given LLVM bitcode files, optionally with an index for faster 1506 lookup.</dd> 1507 1508 <dt><tt><b>llvm-as</b></tt></dt> 1509 <dd>The assembler transforms the human readable LLVM assembly to LLVM 1510 bitcode.</dd> 1511 1512 <dt><tt><b>llvm-dis</b></tt></dt> 1513 <dd>The disassembler transforms the LLVM bitcode to human readable 1514 LLVM assembly.</dd> 1515 1516 <dt><tt><b>llvm-link</b></tt></dt> 1517 <dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into 1518 a single program.</dd> 1519 1520 <dt><tt><b>lli</b></tt></dt> 1521 <dd><tt>lli</tt> is the LLVM interpreter, which 1522 can directly execute LLVM bitcode (although very slowly...). For architectures 1523 that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt> 1524 will function as a Just-In-Time compiler (if the functionality was compiled 1525 in), and will execute the code <i>much</i> faster than the interpreter.</dd> 1526 1527 <dt><tt><b>llc</b></tt></dt> 1528 <dd> <tt>llc</tt> is the LLVM backend compiler, which 1529 translates LLVM bitcode to a native code assembly file or to C code (with 1530 the -march=c option).</dd> 1531 1532 <dt><tt><b>llvm-gcc</b></tt></dt> 1533 <dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to 1534 use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM 1535 bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the 1536 usual machine code output. It works just like any other GCC compiler, 1537 taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used. 1538 Additionally, the source code for <tt>llvm-gcc</tt> is available as a 1539 separate Subversion module.</dd> 1540 1541 <dt><tt><b>opt</b></tt></dt> 1542 <dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM 1543 transformations (which are specified on the command line), and then outputs 1544 the resultant bitcode. The '<tt>opt -help</tt>' command is a good way to 1545 get a list of the program transformations available in LLVM.<br> 1546 <dd><tt>opt</tt> can also be used to run a specific analysis on an input 1547 LLVM bitcode file and print out the results. It is primarily useful for 1548 debugging analyses, or familiarizing yourself with what an analysis does.</dd> 1549 </dl> 1550 </div> 1551 1552 <!-- ======================================================================= --> 1553 <h3> 1554 <a name="utils"><tt>llvm/utils</tt></a> 1555 </h3> 1556 1557 <div> 1558 1559 <p>This directory contains utilities for working with LLVM source code, and some 1560 of the utilities are actually required as part of the build process because they 1561 are code generators for parts of LLVM infrastructure.</p> 1562 1563 <dl> 1564 <dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script 1565 that finds differences between code that LLC generates and code that LLI 1566 generates. This is a useful tool if you are debugging one of them, 1567 assuming that the other generates correct output. For the full user 1568 manual, run <tt>`perldoc codegen-diff'</tt>.<br><br> 1569 1570 <dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains 1571 syntax-highlighting files which will work with Emacs and XEmacs editors, 1572 providing syntax highlighting support for LLVM assembly files and TableGen 1573 description files. For information on how to use the syntax files, consult 1574 the <tt>README</tt> file in that directory.<br><br> 1575 1576 <dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds 1577 and outputs all non-generated source files, which is useful if one wishes 1578 to do a lot of development across directories and does not want to 1579 individually find each file. One way to use it is to run, for example: 1580 <tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source 1581 tree.<br><br> 1582 1583 <dt><tt><b>llvmgrep</b></tt></dt> 1584 <dd>This little tool performs an "egrep -H -n" on each source file in LLVM and 1585 passes to it a regular expression provided on <tt>llvmgrep</tt>'s command 1586 line. This is a very efficient way of searching the source base for a 1587 particular regular expression.</dd> 1588 1589 <dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all 1590 files in the current directory and then compiles and links the tool that 1591 is the first argument. For example, assuming you are in the directory 1592 <tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path, 1593 simply running <tt>makellvm llc</tt> will make a build of the current 1594 directory, switch to directory <tt>llvm/tools/llc</tt> and build it, 1595 causing a re-linking of LLC.<br><br> 1596 1597 <dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains 1598 the tool used to generate register descriptions, instruction set 1599 descriptions, and even assemblers from common TableGen description 1600 files.<br><br> 1601 1602 <dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains 1603 syntax-highlighting files which will work with the VIM editor, providing 1604 syntax highlighting support for LLVM assembly files and TableGen 1605 description files. For information on how to use the syntax files, consult 1606 the <tt>README</tt> file in that directory.<br><br> 1607 1608 </dl> 1609 1610 </div> 1611 1612 </div> 1613 1614 <!-- *********************************************************************** --> 1615 <h2> 1616 <a name="tutorial">An Example Using the LLVM Tool Chain</a> 1617 </h2> 1618 <!-- *********************************************************************** --> 1619 1620 <div> 1621 <p>This section gives an example of using LLVM with the Clang front end.</p> 1622 1623 <!-- ======================================================================= --> 1624 <h3> 1625 <a name="tutorial4">Example with clang</a> 1626 </h3> 1627 1628 <div> 1629 1630 <ol> 1631 <li><p>First, create a simple C file, name it 'hello.c':</p> 1632 1633 <div class="doc_code"> 1634 <pre> 1635 #include <stdio.h> 1636 1637 int main() { 1638 printf("hello world\n"); 1639 return 0; 1640 } 1641 </pre></div></li> 1642 1643 <li><p>Next, compile the C file into a native executable:</p> 1644 1645 <div class="doc_code"><pre>% clang hello.c -o hello</pre></div> 1646 1647 <p>Note that clang works just like GCC by default. The standard -S and 1648 -c arguments work as usual (producing a native .s or .o file, 1649 respectively).</p></li> 1650 1651 <li><p>Next, compile the C file into a LLVM bitcode file:</p> 1652 1653 <div class="doc_code"> 1654 <pre>% clang -O3 -emit-llvm hello.c -c -o hello.bc</pre></div> 1655 1656 <p>The -emit-llvm option can be used with the -S or -c options to emit an 1657 LLVM ".ll" or ".bc" file (respectively) for the code. This allows you 1658 to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on 1659 the bitcode file.</p></li> 1660 1661 <li><p>Run the program in both forms. To run the program, use:</p> 1662 1663 <div class="doc_code"><pre>% ./hello</pre></div> 1664 1665 <p>and</p> 1666 1667 <div class="doc_code"><pre>% lli hello.bc</pre></div> 1668 1669 <p>The second examples shows how to invoke the LLVM JIT, <a 1670 href="CommandGuide/html/lli.html">lli</a>.</p></li> 1671 1672 <li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly 1673 code:</p> 1674 1675 <div class="doc_code"> 1676 <pre>llvm-dis < hello.bc | less</pre> 1677 </div></li> 1678 1679 <li><p>Compile the program to native assembly using the LLC code 1680 generator:</p> 1681 1682 <div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li> 1683 1684 <li><p>Assemble the native assembly language file into a program:</p> 1685 1686 <div class="doc_code"> 1687 <pre> 1688 <b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native 1689 1690 <b>Others:</b> % gcc hello.s -o hello.native 1691 </pre> 1692 </div></li> 1693 1694 <li><p>Execute the native code program:</p> 1695 1696 <div class="doc_code"><pre>% ./hello.native</pre></div> 1697 1698 <p>Note that using clang to compile directly to native code (i.e. when 1699 the -emit-llvm option is not present) does steps 6/7/8 for you.</p> 1700 </li> 1701 1702 </ol> 1703 1704 </div> 1705 1706 </div> 1707 1708 <!-- *********************************************************************** --> 1709 <h2> 1710 <a name="problems">Common Problems</a> 1711 </h2> 1712 <!-- *********************************************************************** --> 1713 1714 <div> 1715 1716 <p>If you are having problems building or using LLVM, or if you have any other 1717 general questions about LLVM, please consult the <a href="FAQ.html">Frequently 1718 Asked Questions</a> page.</p> 1719 1720 </div> 1721 1722 <!-- *********************************************************************** --> 1723 <h2> 1724 <a name="links">Links</a> 1725 </h2> 1726 <!-- *********************************************************************** --> 1727 1728 <div> 1729 1730 <p>This document is just an <b>introduction</b> on how to use LLVM to do 1731 some simple things... there are many more interesting and complicated things 1732 that you can do that aren't documented here (but we'll gladly accept a patch 1733 if you want to write something up!). For more information about LLVM, check 1734 out:</p> 1735 1736 <ul> 1737 <li><a href="http://llvm.org/">LLVM homepage</a></li> 1738 <li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li> 1739 <li><a href="http://llvm.org/docs/Projects.html">Starting a Project 1740 that Uses LLVM</a></li> 1741 </ul> 1742 1743 </div> 1744 1745 <!-- *********************************************************************** --> 1746 1747 <hr> 1748 <address> 1749 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img 1750 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a> 1751 <a href="http://validator.w3.org/check/referer"><img 1752 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a> 1753 1754 <a href="mailto:sabre (a] nondot.org">Chris Lattner</a><br> 1755 <a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br> 1756 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br> 1757 Last modified: $Date$ 1758 </address> 1759 </body> 1760 </html> 1761
