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>Creating an LLVM Project</title> 7 <link rel="stylesheet" href="llvm.css" type="text/css"> 8</head> 9<body> 10 11<h1>Creating an LLVM Project</h1> 12 13<ol> 14<li><a href="#overview">Overview</a></li> 15<li><a href="#create">Create a project from the Sample Project</a></li> 16<li><a href="#source">Source tree layout</a></li> 17<li><a href="#makefiles">Writing LLVM-style Makefiles</a> 18 <ol> 19 <li><a href="#reqVars">Required Variables</a></li> 20 <li><a href="#varsBuildDir">Variables for Building Subdirectories</a></li> 21 <li><a href="#varsBuildLib">Variables for Building Libraries</a></li> 22 <li><a href="#varsBuildProg">Variables for Building Programs</a></li> 23 <li><a href="#miscVars">Miscellaneous Variables</a></li> 24 </ol></li> 25<li><a href="#objcode">Placement of object code</a></li> 26<li><a href="#help">Further help</a></li> 27</ol> 28 29<div class="doc_author"> 30 <p>Written by John Criswell</p> 31</div> 32 33<!-- *********************************************************************** --> 34<h2><a name="overview">Overview</a></h2> 35<!-- *********************************************************************** --> 36 37<div> 38 39<p>The LLVM build system is designed to facilitate the building of third party 40projects that use LLVM header files, libraries, and tools. In order to use 41these facilities, a Makefile from a project must do the following things:</p> 42 43<ol> 44 <li>Set <tt>make</tt> variables. There are several variables that a Makefile 45 needs to set to use the LLVM build system: 46 <ul> 47 <li><tt>PROJECT_NAME</tt> - The name by which your project is known.</li> 48 <li><tt>LLVM_SRC_ROOT</tt> - The root of the LLVM source tree.</li> 49 <li><tt>LLVM_OBJ_ROOT</tt> - The root of the LLVM object tree.</li> 50 <li><tt>PROJ_SRC_ROOT</tt> - The root of the project's source tree.</li> 51 <li><tt>PROJ_OBJ_ROOT</tt> - The root of the project's object tree.</li> 52 <li><tt>PROJ_INSTALL_ROOT</tt> - The root installation directory.</li> 53 <li><tt>LEVEL</tt> - The relative path from the current directory to the 54 project's root ($PROJ_OBJ_ROOT).</li> 55 </ul></li> 56 <li>Include <tt>Makefile.config</tt> from <tt>$(LLVM_OBJ_ROOT)</tt>.</li> 57 <li>Include <tt>Makefile.rules</tt> from <tt>$(LLVM_SRC_ROOT)</tt>.</li> 58</ol> 59 60<p>There are two ways that you can set all of these variables:</p> 61<ol> 62 <li>You can write your own Makefiles which hard-code these values.</li> 63 <li>You can use the pre-made LLVM sample project. This sample project 64 includes Makefiles, a configure script that can be used to configure the 65 location of LLVM, and the ability to support multiple object directories 66 from a single source directory.</li> 67</ol> 68 69<p>This document assumes that you will base your project on the LLVM sample 70project found in <tt>llvm/projects/sample</tt>. If you want to devise your own 71build system, studying the sample project and LLVM Makefiles will probably 72provide enough information on how to write your own Makefiles.</p> 73 74</div> 75 76<!-- *********************************************************************** --> 77<h2> 78 <a name="create">Create a Project from the Sample Project</a> 79</h2> 80<!-- *********************************************************************** --> 81 82<div> 83 84<p>Follow these simple steps to start your project:</p> 85 86<ol> 87<li>Copy the <tt>llvm/projects/sample</tt> directory to any place of your 88choosing. You can place it anywhere you like. Rename the directory to match 89the name of your project.</li> 90 91<li> 92If you downloaded LLVM using Subversion, remove all the directories named .svn 93(and all the files therein) from your project's new source tree. This will 94keep Subversion from thinking that your project is inside 95<tt>llvm/trunk/projects/sample</tt>.</li> 96 97<li>Add your source code and Makefiles to your source tree.</li> 98 99<li>If you want your project to be configured with the <tt>configure</tt> script 100then you need to edit <tt>autoconf/configure.ac</tt> as follows: 101 <ul> 102 <li><b>AC_INIT</b>. Place the name of your project, its version number and 103 a contact email address for your project as the arguments to this macro</li> 104 <li><b>AC_CONFIG_AUX_DIR</b>. If your project isn't in the 105 <tt>llvm/projects</tt> directory then you might need to adjust this so that 106 it specifies a relative path to the <tt>llvm/autoconf</tt> directory.</li> 107 <li><b>LLVM_CONFIG_PROJECT</b>. Just leave this alone.</li> 108 <li><b>AC_CONFIG_SRCDIR</b>. Specify a path to a file name that identifies 109 your project; or just leave it at <tt>Makefile.common.in</tt></li> 110 <li><b>AC_CONFIG_FILES</b>. Do not change.</li> 111 <li><b>AC_CONFIG_MAKEFILE</b>. Use one of these macros for each Makefile 112 that your project uses. This macro arranges for your makefiles to be copied 113 from the source directory, unmodified, to the build directory.</li> 114 </ul> 115</li> 116 117<li>After updating <tt>autoconf/configure.ac</tt>, regenerate the 118configure script with these commands: 119 120<div class="doc_code"> 121<p><tt>% cd autoconf<br> 122 % ./AutoRegen.sh</tt></p> 123</div> 124 125<p>You must be using Autoconf version 2.59 or later and your aclocal version 126should be 1.9 or later.</p></li> 127 128<li>Run <tt>configure</tt> in the directory in which you want to place 129object code. Use the following options to tell your project where it 130can find LLVM: 131 132 <dl> 133 <dt><tt>--with-llvmsrc=<directory></tt></dt> 134 <dd>Tell your project where the LLVM source tree is located.</dd> 135 <dt><br><tt>--with-llvmobj=<directory></tt></dt> 136 <dd>Tell your project where the LLVM object tree is located.</dd> 137 <dt><br><tt>--prefix=<directory></tt></dt> 138 <dd>Tell your project where it should get installed.</dd> 139 </dl> 140</ol> 141 142<p>That's it! Now all you have to do is type <tt>gmake</tt> (or <tt>make</tt> 143if your on a GNU/Linux system) in the root of your object directory, and your 144project should build.</p> 145 146</div> 147 148<!-- *********************************************************************** --> 149<h2> 150 <a name="source">Source Tree Layout</a> 151</h2> 152<!-- *********************************************************************** --> 153 154<div> 155 156<p>In order to use the LLVM build system, you will want to organize your 157source code so that it can benefit from the build system's features. 158Mainly, you want your source tree layout to look similar to the LLVM 159source tree layout. The best way to do this is to just copy the 160project tree from <tt>llvm/projects/sample</tt> and modify it to meet 161your needs, but you can certainly add to it if you want.</p> 162 163<p>Underneath your top level directory, you should have the following 164directories:</p> 165 166<dl> 167 <dt><b>lib</b> 168 <dd> 169 This subdirectory should contain all of your library source 170 code. For each library that you build, you will have one 171 directory in <b>lib</b> that will contain that library's source 172 code. 173 174 <p> 175 Libraries can be object files, archives, or dynamic libraries. 176 The <b>lib</b> directory is just a convenient place for libraries 177 as it places them all in a directory from which they can be linked 178 later. 179 180 <dt><b>include</b> 181 <dd> 182 This subdirectory should contain any header files that are 183 global to your project. By global, we mean that they are used 184 by more than one library or executable of your project. 185 <p> 186 By placing your header files in <b>include</b>, they will be 187 found automatically by the LLVM build system. For example, if 188 you have a file <b>include/jazz/note.h</b>, then your source 189 files can include it simply with <b>#include "jazz/note.h"</b>. 190 191 <dt><b>tools</b> 192 <dd> 193 This subdirectory should contain all of your source 194 code for executables. For each program that you build, you 195 will have one directory in <b>tools</b> that will contain that 196 program's source code. 197 <p> 198 199 <dt><b>test</b> 200 <dd> 201 This subdirectory should contain tests that verify that your code 202 works correctly. Automated tests are especially useful. 203 <p> 204 Currently, the LLVM build system provides basic support for tests. 205 The LLVM system provides the following: 206 <ul> 207 <li> 208 LLVM provides a tcl procedure that is used by Dejagnu to run 209 tests. It can be found in <tt>llvm/lib/llvm-dg.exp</tt>. This 210 test procedure uses RUN lines in the actual test case to determine 211 how to run the test. See the <a 212 href="TestingGuide.html">TestingGuide</a> for more details. You 213 can easily write Makefile support similar to the Makefiles in 214 <tt>llvm/test</tt> to use Dejagnu to run your project's tests.<br></li> 215 <li> 216 LLVM contains an optional package called <tt>llvm-test</tt> 217 which provides benchmarks and programs that are known to compile with the 218 LLVM GCC front ends. You can use these 219 programs to test your code, gather statistics information, and 220 compare it to the current LLVM performance statistics. 221 <br>Currently, there is no way to hook your tests directly into the 222 <tt>llvm/test</tt> testing harness. You will simply 223 need to find a way to use the source provided within that directory 224 on your own. 225 </ul> 226</dl> 227 228<p>Typically, you will want to build your <b>lib</b> directory first followed by 229your <b>tools</b> directory.</p> 230 231</div> 232 233<!-- *********************************************************************** --> 234<h2> 235 <a name="makefiles">Writing LLVM Style Makefiles</a> 236</h2> 237<!-- *********************************************************************** --> 238 239<div> 240 241<p>The LLVM build system provides a convenient way to build libraries and 242executables. Most of your project Makefiles will only need to define a few 243variables. Below is a list of the variables one can set and what they can 244do:</p> 245 246<!-- ======================================================================= --> 247<h3> 248 <a name="reqVars">Required Variables</a> 249</h3> 250 251<div> 252 253<dl> 254 <dt>LEVEL 255 <dd> 256 This variable is the relative path from this Makefile to the 257 top directory of your project's source code. For example, if 258 your source code is in <tt>/tmp/src</tt>, then the Makefile in 259 <tt>/tmp/src/jump/high</tt> would set <tt>LEVEL</tt> to <tt>"../.."</tt>. 260</dl> 261 262</div> 263 264<!-- ======================================================================= --> 265<h3> 266 <a name="varsBuildDir">Variables for Building Subdirectories</a> 267</h3> 268 269<div> 270 271<dl> 272 <dt>DIRS 273 <dd> 274 This is a space separated list of subdirectories that should be 275 built. They will be built, one at a time, in the order 276 specified. 277 <p> 278 279 <dt>PARALLEL_DIRS 280 <dd> 281 This is a list of directories that can be built in parallel. 282 These will be built after the directories in DIRS have been 283 built. 284 <p> 285 286 <dt>OPTIONAL_DIRS 287 <dd> 288 This is a list of directories that can be built if they exist, 289 but will not cause an error if they do not exist. They are 290 built serially in the order in which they are listed. 291</dl> 292 293</div> 294 295<!-- ======================================================================= --> 296<h3> 297 <a name="varsBuildLib">Variables for Building Libraries</a> 298</h3> 299 300<div> 301 302<dl> 303 <dt>LIBRARYNAME 304 <dd> 305 This variable contains the base name of the library that will 306 be built. For example, to build a library named 307 <tt>libsample.a</tt>, LIBRARYNAME should be set to 308 <tt>sample</tt>. 309 <p> 310 311 <dt>BUILD_ARCHIVE 312 <dd> 313 By default, a library is a <tt>.o</tt> file that is linked 314 directly into a program. To build an archive (also known as 315 a static library), set the BUILD_ARCHIVE variable. 316 <p> 317 318 <dt>SHARED_LIBRARY 319 <dd> 320 If SHARED_LIBRARY is defined in your Makefile, a shared 321 (or dynamic) library will be built. 322</dl> 323 324</div> 325 326<!-- ======================================================================= --> 327<h3> 328 <a name="varsBuildProg">Variables for Building Programs</a> 329</h3> 330 331<div> 332 333<dl> 334 <dt>TOOLNAME 335 <dd> 336 This variable contains the name of the program that will 337 be built. For example, to build an executable named 338 <tt>sample</tt>, TOOLNAME should be set to <tt>sample</tt>. 339 <p> 340 341 <dt>USEDLIBS 342 <dd> 343 This variable holds a space separated list of libraries that should 344 be linked into the program. These libraries must be libraries that 345 come from your <b>lib</b> directory. The libraries must be 346 specified without their "lib" prefix. For example, to link 347 libsample.a, you would set USEDLIBS to 348 <tt>sample.a</tt>. 349 <p> 350 Note that this works only for statically linked libraries. 351 <p> 352 353 <dt>LLVMLIBS 354 <dd> 355 This variable holds a space separated list of libraries that should 356 be linked into the program. These libraries must be LLVM libraries. 357 The libraries must be specified without their "lib" prefix. For 358 example, to link with a driver that performs an IR transformation 359 you might set LLVMLIBS to this minimal set of libraries 360 <tt>LLVMSupport.a LLVMCore.a LLVMBitReader.a LLVMAsmParser.a LLVMAnalysis.a LLVMTransformUtils.a LLVMScalarOpts.a LLVMTarget.a</tt>. 361 <p> 362 Note that this works only for statically linked libraries. LLVM is 363 split into a large number of static libraries, and the list of libraries you 364 require may be much longer than the list above. To see a full list 365 of libraries use: 366 <tt>llvm-config --libs all</tt>. 367 Using LINK_COMPONENTS as described below, obviates the need to set LLVMLIBS. 368 <p> 369 370 <dt>LINK_COMPONENTS 371 <dd>This variable holds a space separated list of components that 372 the LLVM Makefiles pass to the <tt>llvm-config</tt> tool to generate 373 a link line for the program. For example, to link with all LLVM 374 libraries use 375 <tt>LINK_COMPONENTS = all</tt>. 376 <p> 377 378 <dt>LIBS 379 <dd> 380 To link dynamic libraries, add <tt>-l<library base name></tt> to 381 the LIBS variable. The LLVM build system will look in the same places 382 for dynamic libraries as it does for static libraries. 383 <p> 384 For example, to link <tt>libsample.so</tt>, you would have the 385 following line in your <tt>Makefile</tt>: 386 <p> 387 <tt> 388 LIBS += -lsample 389 </tt> 390 <p> 391 Note that LIBS must occur in the Makefile after the inclusion of Makefile.common. 392 <p> 393</dl> 394 395</div> 396 397<!-- ======================================================================= --> 398<h3> 399 <a name="miscVars">Miscellaneous Variables</a> 400</h3> 401 402<div> 403 404<dl> 405 <dt>ExtraSource 406 <dd> 407 This variable contains a space separated list of extra source 408 files that need to be built. It is useful for including the 409 output of Lex and Yacc programs. 410 <p> 411 412 <dt>CFLAGS 413 <dt>CPPFLAGS 414 <dd> 415 This variable can be used to add options to the C and C++ 416 compiler, respectively. It is typically used to add options 417 that tell the compiler the location of additional directories 418 to search for header files. 419 <p> 420 It is highly suggested that you append to CFLAGS and CPPFLAGS as 421 opposed to overwriting them. The master Makefiles may already 422 have useful options in them that you may not want to overwrite. 423 <p> 424</dl> 425 426</div> 427 428</div> 429 430<!-- *********************************************************************** --> 431<h2> 432 <a name="objcode">Placement of Object Code</a> 433</h2> 434<!-- *********************************************************************** --> 435 436<div> 437 438<p>The final location of built libraries and executables will depend upon 439whether you do a Debug, Release, or Profile build.</p> 440 441<dl> 442 <dt>Libraries 443 <dd> 444 All libraries (static and dynamic) will be stored in 445 <tt>PROJ_OBJ_ROOT/<type>/lib</tt>, where type is <tt>Debug</tt>, 446 <tt>Release</tt>, or <tt>Profile</tt> for a debug, optimized, or 447 profiled build, respectively.<p> 448 449 <dt>Executables 450 <dd>All executables will be stored in 451 <tt>PROJ_OBJ_ROOT/<type>/bin</tt>, where type is <tt>Debug</tt>, 452 <tt>Release</tt>, or <tt>Profile</tt> for a debug, optimized, or profiled 453 build, respectively. 454</dl> 455 456</div> 457 458<!-- *********************************************************************** --> 459<h2> 460 <a name="help">Further Help</a> 461</h2> 462<!-- *********************************************************************** --> 463 464<div> 465 466<p>If you have any questions or need any help creating an LLVM project, 467the LLVM team would be more than happy to help. You can always post your 468questions to the <a 469href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developers 470Mailing List</a>.</p> 471 472</div> 473 474<!-- *********************************************************************** --> 475<hr> 476<address> 477 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img 478 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a> 479 <a href="http://validator.w3.org/check/referer"><img 480 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a> 481 482 <a href="mailto:criswell@uiuc.edu">John Criswell</a><br> 483 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a> 484 <br> 485 Last modified: $Date$ 486</address> 487 488</body> 489</html> 490