1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" 2 "http://www.w3.org/TR/html4/strict.dtd"> 3<html> 4<head> 5 <title>Creating an LLVM Project</title> 6 <link rel="stylesheet" href="llvm.css" type="text/css"> 7</head> 8<body> 9 10<h1>Creating an LLVM Project</h1> 11 12<ol> 13<li><a href="#overview">Overview</a></li> 14<li><a href="#create">Create a project from the Sample Project</a></li> 15<li><a href="#source">Source tree layout</a></li> 16<li><a href="#makefiles">Writing LLVM-style Makefiles</a> 17 <ol> 18 <li><a href="#reqVars">Required Variables</a></li> 19 <li><a href="#varsBuildDir">Variables for Building Subdirectories</a></li> 20 <li><a href="#varsBuildLib">Variables for Building Libraries</a></li> 21 <li><a href="#varsBuildProg">Variables for Building Programs</a></li> 22 <li><a href="#miscVars">Miscellaneous Variables</a></li> 23 </ol></li> 24<li><a href="#objcode">Placement of object code</a></li> 25<li><a href="#help">Further help</a></li> 26</ol> 27 28<div class="doc_author"> 29 <p>Written by John Criswell</p> 30</div> 31 32<!-- *********************************************************************** --> 33<h2><a name="overview">Overview</a></h2> 34<!-- *********************************************************************** --> 35 36<div> 37 38<p>The LLVM build system is designed to facilitate the building of third party 39projects that use LLVM header files, libraries, and tools. In order to use 40these facilities, a Makefile from a project must do the following things:</p> 41 42<ol> 43 <li>Set <tt>make</tt> variables. There are several variables that a Makefile 44 needs to set to use the LLVM build system: 45 <ul> 46 <li><tt>PROJECT_NAME</tt> - The name by which your project is known.</li> 47 <li><tt>LLVM_SRC_ROOT</tt> - The root of the LLVM source tree.</li> 48 <li><tt>LLVM_OBJ_ROOT</tt> - The root of the LLVM object tree.</li> 49 <li><tt>PROJ_SRC_ROOT</tt> - The root of the project's source tree.</li> 50 <li><tt>PROJ_OBJ_ROOT</tt> - The root of the project's object tree.</li> 51 <li><tt>PROJ_INSTALL_ROOT</tt> - The root installation directory.</li> 52 <li><tt>LEVEL</tt> - The relative path from the current directory to the 53 project's root ($PROJ_OBJ_ROOT).</li> 54 </ul></li> 55 <li>Include <tt>Makefile.config</tt> from <tt>$(LLVM_OBJ_ROOT)</tt>.</li> 56 <li>Include <tt>Makefile.rules</tt> from <tt>$(LLVM_SRC_ROOT)</tt>.</li> 57</ol> 58 59<p>There are two ways that you can set all of these variables:</p> 60<ol> 61 <li>You can write your own Makefiles which hard-code these values.</li> 62 <li>You can use the pre-made LLVM sample project. This sample project 63 includes Makefiles, a configure script that can be used to configure the 64 location of LLVM, and the ability to support multiple object directories 65 from a single source directory.</li> 66</ol> 67 68<p>This document assumes that you will base your project on the LLVM sample 69project found in <tt>llvm/projects/sample</tt>. If you want to devise your own 70build system, studying the sample project and LLVM Makefiles will probably 71provide enough information on how to write your own Makefiles.</p> 72 73</div> 74 75<!-- *********************************************************************** --> 76<h2> 77 <a name="create">Create a Project from the Sample Project</a> 78</h2> 79<!-- *********************************************************************** --> 80 81<div> 82 83<p>Follow these simple steps to start your project:</p> 84 85<ol> 86<li>Copy the <tt>llvm/projects/sample</tt> directory to any place of your 87choosing. You can place it anywhere you like. Rename the directory to match 88the name of your project.</li> 89 90<li> 91If you downloaded LLVM using Subversion, remove all the directories named .svn 92(and all the files therein) from your project's new source tree. This will 93keep Subversion from thinking that your project is inside 94<tt>llvm/trunk/projects/sample</tt>.</li> 95 96<li>Add your source code and Makefiles to your source tree.</li> 97 98<li>If you want your project to be configured with the <tt>configure</tt> script 99then you need to edit <tt>autoconf/configure.ac</tt> as follows: 100 <ul> 101 <li><b>AC_INIT</b>. Place the name of your project, its version number and 102 a contact email address for your project as the arguments to this macro</li> 103 <li><b>AC_CONFIG_AUX_DIR</b>. If your project isn't in the 104 <tt>llvm/projects</tt> directory then you might need to adjust this so that 105 it specifies a relative path to the <tt>llvm/autoconf</tt> directory.</li> 106 <li><b>LLVM_CONFIG_PROJECT</b>. Just leave this alone.</li> 107 <li><b>AC_CONFIG_SRCDIR</b>. Specify a path to a file name that identifies 108 your project; or just leave it at <tt>Makefile.common.in</tt></li> 109 <li><b>AC_CONFIG_FILES</b>. Do not change.</li> 110 <li><b>AC_CONFIG_MAKEFILE</b>. Use one of these macros for each Makefile 111 that your project uses. This macro arranges for your makefiles to be copied 112 from the source directory, unmodified, to the build directory.</li> 113 </ul> 114</li> 115 116<li>After updating <tt>autoconf/configure.ac</tt>, regenerate the 117configure script with these commands: 118 119<div class="doc_code"> 120<p><tt>% cd autoconf<br> 121 % ./AutoRegen.sh</tt></p> 122</div> 123 124<p>You must be using Autoconf version 2.59 or later and your aclocal version 125should be 1.9 or later.</p></li> 126 127<li>Run <tt>configure</tt> in the directory in which you want to place 128object code. Use the following options to tell your project where it 129can find LLVM: 130 131 <dl> 132 <dt><tt>--with-llvmsrc=<directory></tt></dt> 133 <dd>Tell your project where the LLVM source tree is located.</dd> 134 <dt><br><tt>--with-llvmobj=<directory></tt></dt> 135 <dd>Tell your project where the LLVM object tree is located.</dd> 136 <dt><br><tt>--prefix=<directory></tt></dt> 137 <dd>Tell your project where it should get installed.</dd> 138 </dl> 139</ol> 140 141<p>That's it! Now all you have to do is type <tt>gmake</tt> (or <tt>make</tt> 142if your on a GNU/Linux system) in the root of your object directory, and your 143project should build.</p> 144 145</div> 146 147<!-- *********************************************************************** --> 148<h2> 149 <a name="source">Source Tree Layout</a> 150</h2> 151<!-- *********************************************************************** --> 152 153<div> 154 155<p>In order to use the LLVM build system, you will want to organize your 156source code so that it can benefit from the build system's features. 157Mainly, you want your source tree layout to look similar to the LLVM 158source tree layout. The best way to do this is to just copy the 159project tree from <tt>llvm/projects/sample</tt> and modify it to meet 160your needs, but you can certainly add to it if you want.</p> 161 162<p>Underneath your top level directory, you should have the following 163directories:</p> 164 165<dl> 166 <dt><b>lib</b> 167 <dd> 168 This subdirectory should contain all of your library source 169 code. For each library that you build, you will have one 170 directory in <b>lib</b> that will contain that library's source 171 code. 172 173 <p> 174 Libraries can be object files, archives, or dynamic libraries. 175 The <b>lib</b> directory is just a convenient place for libraries 176 as it places them all in a directory from which they can be linked 177 later. 178 179 <dt><b>include</b> 180 <dd> 181 This subdirectory should contain any header files that are 182 global to your project. By global, we mean that they are used 183 by more than one library or executable of your project. 184 <p> 185 By placing your header files in <b>include</b>, they will be 186 found automatically by the LLVM build system. For example, if 187 you have a file <b>include/jazz/note.h</b>, then your source 188 files can include it simply with <b>#include "jazz/note.h"</b>. 189 190 <dt><b>tools</b> 191 <dd> 192 This subdirectory should contain all of your source 193 code for executables. For each program that you build, you 194 will have one directory in <b>tools</b> that will contain that 195 program's source code. 196 <p> 197 198 <dt><b>test</b> 199 <dd> 200 This subdirectory should contain tests that verify that your code 201 works correctly. Automated tests are especially useful. 202 <p> 203 Currently, the LLVM build system provides basic support for tests. 204 The LLVM system provides the following: 205 <ul> 206 <li> 207 LLVM provides a tcl procedure that is used by Dejagnu to run 208 tests. It can be found in <tt>llvm/lib/llvm-dg.exp</tt>. This 209 test procedure uses RUN lines in the actual test case to determine 210 how to run the test. See the <a 211 href="TestingGuide.html">TestingGuide</a> for more details. You 212 can easily write Makefile support similar to the Makefiles in 213 <tt>llvm/test</tt> to use Dejagnu to run your project's tests.<br></li> 214 <li> 215 LLVM contains an optional package called <tt>llvm-test</tt> 216 which provides benchmarks and programs that are known to compile with the 217 LLVM GCC front ends. You can use these 218 programs to test your code, gather statistics information, and 219 compare it to the current LLVM performance statistics. 220 <br>Currently, there is no way to hook your tests directly into the 221 <tt>llvm/test</tt> testing harness. You will simply 222 need to find a way to use the source provided within that directory 223 on your own. 224 </ul> 225</dl> 226 227<p>Typically, you will want to build your <b>lib</b> directory first followed by 228your <b>tools</b> directory.</p> 229 230</div> 231 232<!-- *********************************************************************** --> 233<h2> 234 <a name="makefiles">Writing LLVM Style Makefiles</a> 235</h2> 236<!-- *********************************************************************** --> 237 238<div> 239 240<p>The LLVM build system provides a convenient way to build libraries and 241executables. Most of your project Makefiles will only need to define a few 242variables. Below is a list of the variables one can set and what they can 243do:</p> 244 245<!-- ======================================================================= --> 246<h3> 247 <a name="reqVars">Required Variables</a> 248</h3> 249 250<div> 251 252<dl> 253 <dt>LEVEL 254 <dd> 255 This variable is the relative path from this Makefile to the 256 top directory of your project's source code. For example, if 257 your source code is in <tt>/tmp/src</tt>, then the Makefile in 258 <tt>/tmp/src/jump/high</tt> would set <tt>LEVEL</tt> to <tt>"../.."</tt>. 259</dl> 260 261</div> 262 263<!-- ======================================================================= --> 264<h3> 265 <a name="varsBuildDir">Variables for Building Subdirectories</a> 266</h3> 267 268<div> 269 270<dl> 271 <dt>DIRS 272 <dd> 273 This is a space separated list of subdirectories that should be 274 built. They will be built, one at a time, in the order 275 specified. 276 <p> 277 278 <dt>PARALLEL_DIRS 279 <dd> 280 This is a list of directories that can be built in parallel. 281 These will be built after the directories in DIRS have been 282 built. 283 <p> 284 285 <dt>OPTIONAL_DIRS 286 <dd> 287 This is a list of directories that can be built if they exist, 288 but will not cause an error if they do not exist. They are 289 built serially in the order in which they are listed. 290</dl> 291 292</div> 293 294<!-- ======================================================================= --> 295<h3> 296 <a name="varsBuildLib">Variables for Building Libraries</a> 297</h3> 298 299<div> 300 301<dl> 302 <dt>LIBRARYNAME 303 <dd> 304 This variable contains the base name of the library that will 305 be built. For example, to build a library named 306 <tt>libsample.a</tt>, LIBRARYNAME should be set to 307 <tt>sample</tt>. 308 <p> 309 310 <dt>BUILD_ARCHIVE 311 <dd> 312 By default, a library is a <tt>.o</tt> file that is linked 313 directly into a program. To build an archive (also known as 314 a static library), set the BUILD_ARCHIVE variable. 315 <p> 316 317 <dt>SHARED_LIBRARY 318 <dd> 319 If SHARED_LIBRARY is defined in your Makefile, a shared 320 (or dynamic) library will be built. 321</dl> 322 323</div> 324 325<!-- ======================================================================= --> 326<h3> 327 <a name="varsBuildProg">Variables for Building Programs</a> 328</h3> 329 330<div> 331 332<dl> 333 <dt>TOOLNAME 334 <dd> 335 This variable contains the name of the program that will 336 be built. For example, to build an executable named 337 <tt>sample</tt>, TOOLNAME should be set to <tt>sample</tt>. 338 <p> 339 340 <dt>USEDLIBS 341 <dd> 342 This variable holds a space separated list of libraries that should 343 be linked into the program. These libraries must be libraries that 344 come from your <b>lib</b> directory. The libraries must be 345 specified without their "lib" prefix. For example, to link 346 libsample.a, you would set USEDLIBS to 347 <tt>sample.a</tt>. 348 <p> 349 Note that this works only for statically linked libraries. 350 <p> 351 352 <dt>LLVMLIBS 353 <dd> 354 This variable holds a space separated list of libraries that should 355 be linked into the program. These libraries must be LLVM libraries. 356 The libraries must be specified without their "lib" prefix. For 357 example, to link with a driver that performs an IR transformation 358 you might set LLVMLIBS to this minimal set of libraries 359 <tt>LLVMSupport.a LLVMCore.a LLVMBitReader.a LLVMAsmParser.a LLVMAnalysis.a LLVMTransformUtils.a LLVMScalarOpts.a LLVMTarget.a</tt>. 360 <p> 361 Note that this works only for statically linked libraries. LLVM is 362 split into a large number of static libraries, and the list of libraries you 363 require may be much longer than the list above. To see a full list 364 of libraries use: 365 <tt>llvm-config --libs all</tt>. 366 Using LINK_COMPONENTS as described below, obviates the need to set LLVMLIBS. 367 <p> 368 369 <dt>LINK_COMPONENTS 370 <dd>This variable holds a space separated list of components that 371 the LLVM Makefiles pass to the <tt>llvm-config</tt> tool to generate 372 a link line for the program. For example, to link with all LLVM 373 libraries use 374 <tt>LINK_COMPONENTS = all</tt>. 375 <p> 376 377 <dt>LIBS 378 <dd> 379 To link dynamic libraries, add <tt>-l<library base name></tt> to 380 the LIBS variable. The LLVM build system will look in the same places 381 for dynamic libraries as it does for static libraries. 382 <p> 383 For example, to link <tt>libsample.so</tt>, you would have the 384 following line in your <tt>Makefile</tt>: 385 <p> 386 <tt> 387 LIBS += -lsample 388 </tt> 389 <p> 390 Note that LIBS must occur in the Makefile after the inclusion of Makefile.common. 391 <p> 392</dl> 393 394</div> 395 396<!-- ======================================================================= --> 397<h3> 398 <a name="miscVars">Miscellaneous Variables</a> 399</h3> 400 401<div> 402 403<dl> 404 <dt>ExtraSource 405 <dd> 406 This variable contains a space separated list of extra source 407 files that need to be built. It is useful for including the 408 output of Lex and Yacc programs. 409 <p> 410 411 <dt>CFLAGS 412 <dt>CPPFLAGS 413 <dd> 414 This variable can be used to add options to the C and C++ 415 compiler, respectively. It is typically used to add options 416 that tell the compiler the location of additional directories 417 to search for header files. 418 <p> 419 It is highly suggested that you append to CFLAGS and CPPFLAGS as 420 opposed to overwriting them. The master Makefiles may already 421 have useful options in them that you may not want to overwrite. 422 <p> 423</dl> 424 425</div> 426 427</div> 428 429<!-- *********************************************************************** --> 430<h2> 431 <a name="objcode">Placement of Object Code</a> 432</h2> 433<!-- *********************************************************************** --> 434 435<div> 436 437<p>The final location of built libraries and executables will depend upon 438whether you do a Debug, Release, or Profile build.</p> 439 440<dl> 441 <dt>Libraries 442 <dd> 443 All libraries (static and dynamic) will be stored in 444 <tt>PROJ_OBJ_ROOT/<type>/lib</tt>, where type is <tt>Debug</tt>, 445 <tt>Release</tt>, or <tt>Profile</tt> for a debug, optimized, or 446 profiled build, respectively.<p> 447 448 <dt>Executables 449 <dd>All executables will be stored in 450 <tt>PROJ_OBJ_ROOT/<type>/bin</tt>, where type is <tt>Debug</tt>, 451 <tt>Release</tt>, or <tt>Profile</tt> for a debug, optimized, or profiled 452 build, respectively. 453</dl> 454 455</div> 456 457<!-- *********************************************************************** --> 458<h2> 459 <a name="help">Further Help</a> 460</h2> 461<!-- *********************************************************************** --> 462 463<div> 464 465<p>If you have any questions or need any help creating an LLVM project, 466the LLVM team would be more than happy to help. You can always post your 467questions to the <a 468href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developers 469Mailing List</a>.</p> 470 471</div> 472 473<!-- *********************************************************************** --> 474<hr> 475<address> 476 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img 477 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a> 478 <a href="http://validator.w3.org/check/referer"><img 479 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a> 480 481 <a href="mailto:criswell@uiuc.edu">John Criswell</a><br> 482 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a> 483 <br> 484 Last modified: $Date: 2011-06-02 22:20:48 -0400 (Thu, 02 Jun 2011) $ 485</address> 486 487</body> 488</html> 489