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10 <h1>LLVM Makefile Guide</h1>
13 <li><a href="#introduction">Introduction</a></li>
14 <li><a href="#general">General Concepts</a>
16 <li><a href="#projects">Projects</a></li>
17 <li><a href="#varvals">Variable Values</a></li>
18 <li><a href="#including">Including Makefiles</a>
20 <li><a href="#Makefile">Makefile</a></li>
21 <li><a href="#Makefile.common">Makefile.common</a></li>
22 <li><a href="#Makefile.config">Makefile.config</a></li>
23 <li><a href="#Makefile.rules">Makefile.rules</a></li>
26 <li><a href="#Comments">Comments</a></li>
29 <li><a href="#tutorial">Tutorial</a>
31 <li><a href="#libraries">Libraries</a>
33 <li><a href="#BCModules">Bitcode Modules</a></li>
34 <li><a href="#LoadableModules">Loadable Modules</a></li>
37 <li><a href="#tools">Tools</a>
39 <li><a href="#JIT">JIT Tools</a></li>
42 <li><a href="#projects">Projects</a></li>
45 <li><a href="#targets">Targets Supported</a>
47 <li><a href="#all">all</a></li>
48 <li><a href="#all-local">all-local</a></li>
49 <li><a href="#check">check</a></li>
50 <li><a href="#check-local">check-local</a></li>
51 <li><a href="#clean">clean</a></li>
52 <li><a href="#clean-local">clean-local</a></li>
53 <li><a href="#dist">dist</a></li>
54 <li><a href="#dist-check">dist-check</a></li>
55 <li><a href="#dist-clean">dist-clean</a></li>
56 <li><a href="#install">install</a></li>
57 <li><a href="#preconditions">preconditions</a></li>
58 <li><a href="#printvars">printvars</a></li>
59 <li><a href="#reconfigure">reconfigure</a></li>
60 <li><a href="#spotless">spotless</a></li>
61 <li><a href="#tags">tags</a></li>
62 <li><a href="#uninstall">uninstall</a></li>
65 <li><a href="#variables">Using Variables</a>
67 <li><a href="#setvars">Control Variables</a></li>
68 <li><a href="#overvars">Override Variables</a></li>
69 <li><a href="#getvars">Readable Variables</a></li>
70 <li><a href="#intvars">Internal Variables</a></li>
75 <div class="doc_author">
76 <p>Written by <a href="mailto:reid@x10sys.com">Reid Spencer</a></p>
79 <!-- *********************************************************************** -->
80 <h2><a name="introduction">Introduction</a></h2>
81 <!-- *********************************************************************** -->
83 <div class="doc_text">
84 <p>This document provides <em>usage</em> information about the LLVM makefile
85 system. While loosely patterned after the BSD makefile system, LLVM has taken
86 a departure from BSD in order to implement additional features needed by LLVM.
87 Although makefile systems such as automake were attempted at one point, it
88 has become clear that the features needed by LLVM and the Makefile norm are
89 too great to use a more limited tool. Consequently, LLVM requires simply GNU
90 Make 3.79, a widely portable makefile processor. LLVM unabashedly makes heavy
91 use of the features of GNU Make so the dependency on GNU Make is firm. If
92 you're not familiar with <tt>make</tt>, it is recommended that you read the
93 <a href="http://www.gnu.org/software/make/manual/make.html">GNU Makefile
95 <p>While this document is rightly part of the
96 <a href="ProgrammersManual.html">LLVM Programmer's Manual</a>, it is treated
97 separately here because of the volume of content and because it is often an
98 early source of bewilderment for new developers.</p>
101 <!-- *********************************************************************** -->
102 <h2><a name="general">General Concepts</a></h2>
103 <!-- *********************************************************************** -->
105 <div class="doc_text">
106 <p>The LLVM Makefile System is the component of LLVM that is responsible for
107 building the software, testing it, generating distributions, checking those
108 distributions, installing and uninstalling, etc. It consists of a several
109 files throughout the source tree. These files and other general concepts are
110 described in this section.</p>
113 <!-- ======================================================================= -->
114 <h3><a name="projects">Projects</a></h3>
115 <div class="doc_text">
116 <p>The LLVM Makefile System is quite generous. It not only builds its own
117 software, but it can build yours too. Built into the system is knowledge of
118 the <tt>llvm/projects</tt> directory. Any directory under <tt>projects</tt>
119 that has both a <tt>configure</tt> script and a <tt>Makefile</tt> is assumed
120 to be a project that uses the LLVM Makefile system. Building software that
121 uses LLVM does not require the LLVM Makefile System nor even placement in the
122 <tt>llvm/projects</tt> directory. However, doing so will allow your project
123 to get up and running quickly by utilizing the built-in features that are used
124 to compile LLVM. LLVM compiles itself using the same features of the makefile
125 system as used for projects.</p>
126 <p>For complete details on setting up your projects configuration, simply
127 mimic the <tt>llvm/projects/sample</tt> project or for further details,
128 consult the <a href="Projects.html">Projects.html</a> page.</p>
131 <!-- ======================================================================= -->
132 <h3><a name="varvalues">Variable Values</a></h3>
133 <div class="doc_text">
134 <p>To use the makefile system, you simply create a file named
135 <tt>Makefile</tt> in your directory and declare values for certain variables.
136 The variables and values that you select determine what the makefile system
137 will do. These variables enable rules and processing in the makefile system
138 that automatically Do The Right Thing™.
141 <!-- ======================================================================= -->
142 <h3><a name="including">Including Makefiles</a></h3>
143 <div class="doc_text">
144 <p>Setting variables alone is not enough. You must include into your Makefile
145 additional files that provide the rules of the LLVM Makefile system. The
146 various files involved are described in the sections that follow.</p>
149 <!-- ======================================================================= -->
150 <h4><a name="Makefile">Makefile</a></h4>
151 <div class="doc_text">
152 <p>Each directory to participate in the build needs to have a file named
153 <tt>Makefile</tt>. This is the file first read by <tt>make</tt>. It has three
156 <li><a href="#setvars">Settable Variables</a> - Required that must be set
158 <li><a href="#Makefile.common">include <tt>$(LEVEL)/Makefile.common</tt></a>
159 - include the LLVM Makefile system.
160 <li><a href="#overvars">Override Variables</a> - Override variables set by
161 the LLVM Makefile system.
165 <!-- ======================================================================= -->
166 <h4><a name="Makefile.common">Makefile.common</a></h4>
167 <div class="doc_text">
168 <p>Every project must have a <tt>Makefile.common</tt> file at its top source
169 directory. This file serves three purposes:</p>
171 <li>It includes the project's configuration makefile to obtain values
172 determined by the <tt>configure</tt> script. This is done by including the
173 <a href="#Makefile.config"><tt>$(LEVEL)/Makefile.config</tt></a> file.</li>
174 <li>It specifies any other (static) values that are needed throughout the
175 project. Only values that are used in all or a large proportion of the
176 project's directories should be placed here.</li>
177 <li>It includes the standard rules for the LLVM Makefile system,
178 <a href="#Makefile.rules"><tt>$(LLVM_SRC_ROOT)/Makefile.rules</tt></a>.
179 This file is the "guts" of the LLVM Makefile system.</li>
183 <!-- ======================================================================= -->
184 <h4><a name="Makefile.config">Makefile.config</a></h4>
185 <div class="doc_text">
186 <p>Every project must have a <tt>Makefile.config</tt> at the top of its
187 <em>build</em> directory. This file is <b>generated</b> by the
188 <tt>configure</tt> script from the pattern provided by the
189 <tt>Makefile.config.in</tt> file located at the top of the project's
190 <em>source</em> directory. The contents of this file depend largely on what
191 configuration items the project uses, however most projects can get what they
192 need by just relying on LLVM's configuration found in
193 <tt>$(LLVM_OBJ_ROOT)/Makefile.config</tt>.
196 <!-- ======================================================================= -->
197 <h4><a name="Makefile.rules">Makefile.rules</a></h4>
198 <div class="doc_text">
199 <p>This file, located at <tt>$(LLVM_SRC_ROOT)/Makefile.rules</tt> is the heart
200 of the LLVM Makefile System. It provides all the logic, dependencies, and
201 rules for building the targets supported by the system. What it does largely
202 depends on the values of <tt>make</tt> <a href="#variables">variables</a> that
203 have been set <em>before</em> <tt>Makefile.rules</tt> is included.
206 <!-- ======================================================================= -->
207 <h3><a name="Comments">Comments</a></h3>
208 <div class="doc_text">
209 <p>User Makefiles need not have comments in them unless the construction is
210 unusual or it does not strictly follow the rules and patterns of the LLVM
211 makefile system. Makefile comments are invoked with the pound (#) character.
212 The # character and any text following it, to the end of the line, are ignored
213 by <tt>make</tt>.</p>
216 <!-- *********************************************************************** -->
217 <h2><a name="tutorial">Tutorial</a></h2>
218 <!-- *********************************************************************** -->
219 <div class="doc_text">
220 <p>This section provides some examples of the different kinds of modules you
221 can build with the LLVM makefile system. In general, each directory you
222 provide will build a single object although that object may be composed of
223 additionally compiled components.</p>
226 <!-- ======================================================================= -->
227 <h3><a name="libraries">Libraries</a></h3>
228 <div class="doc_text">
229 <p>Only a few variable definitions are needed to build a regular library.
230 Normally, the makefile system will build all the software into a single
231 <tt>libname.o</tt> (pre-linked) object. This means the library is not
232 searchable and that the distinction between compilation units has been
233 dissolved. Optionally, you can ask for a shared library (.so) or archive
234 library (.a) built. Archive libraries are the default. For example:</p>
240 <p>says to build a library named "mylib" with both a shared library
241 (<tt>mylib.so</tt>) and an archive library (<tt>mylib.a</tt>) version. The
243 libraries produced will be the same, they are just constructed differently.
244 Note that you normally do not need to specify the sources involved. The LLVM
245 Makefile system will infer the source files from the contents of the source
247 <p>The <tt>LOADABLE_MODULE=1</tt> directive can be used in conjunction with
248 <tt>SHARED_LIBRARY=1</tt> to indicate that the resulting shared library should
249 be openable with the <tt>dlopen</tt> function and searchable with the
250 <tt>dlsym</tt> function (or your operating system's equivalents). While this
251 isn't strictly necessary on Linux and a few other platforms, it is required
252 on systems like HP-UX and Darwin. You should use <tt>LOADABLE_MODULE</tt> for
253 any shared library that you intend to be loaded into an tool via the
254 <tt>-load</tt> option. See the
255 <a href="WritingAnLLVMPass.html#makefile">WritingAnLLVMPass.html</a> document
256 for an example of why you might want to do this.
259 <!-- ======================================================================= -->
260 <h4><a name="BCModules">Bitcode Modules</a></h4>
261 <div class="doc_text">
262 <p>In some situations, it is desirable to build a single bitcode module from
263 a variety of sources, instead of an archive, shared library, or bitcode
264 library. Bitcode modules can be specified in addition to any of the other
265 types of libraries by defining the <a href="#MODULE_NAME">MODULE_NAME</a>
266 variable. For example:</p>
272 <p>will build a module named <tt>mymod.bc</tt> from the sources in the
273 directory. This module will be an aggregation of all the bitcode modules
274 derived from the sources. The example will also build a bitcode archive
275 containing a bitcode module for each compiled source file. The difference is
276 subtle, but important depending on how the module or library is to be linked.
280 <!-- ======================================================================= -->
282 <a name="LoadableModules">Loadable Modules</a>
284 <div class="doc_text">
285 <p>In some situations, you need to create a loadable module. Loadable modules
286 can be loaded into programs like <tt>opt</tt> or <tt>llc</tt> to specify
287 additional passes to run or targets to support. Loadable modules are also
288 useful for debugging a pass or providing a pass with another package if that
289 pass can't be included in LLVM.</p>
290 <p>LLVM provides complete support for building such a module. All you need to
291 do is use the LOADABLE_MODULE variable in your Makefile. For example, to
292 build a loadable module named <tt>MyMod</tt> that uses the LLVM libraries
293 <tt>LLVMSupport.a</tt> and <tt>LLVMSystem.a</tt>, you would specify:</p>
297 LINK_COMPONENTS := support system
299 <p>Use of the <tt>LOADABLE_MODULE</tt> facility implies several things:</p>
301 <li>There will be no "lib" prefix on the module. This differentiates it from
302 a standard shared library of the same name.</li>
303 <li>The <a href="#SHARED_LIBRARY">SHARED_LIBRARY</a> variable is turned
305 <li>The <a href="#LINK_LIBS_IN_SHARED">LINK_LIBS_IN_SHARED</a> variable
308 <p>A loadable module is loaded by LLVM via the facilities of libtool's libltdl
309 library which is part of <tt>lib/System</tt> implementation.</p>
312 <!-- ======================================================================= -->
313 <h3><a name="tools">Tools</a></h3>
314 <div class="doc_text">
315 <p>For building executable programs (tools), you must provide the name of the
316 tool and the names of the libraries you wish to link with the tool. For
321 LINK_COMPONENTS = support system
323 <p>says that we are to build a tool name <tt>mytool</tt> and that it requires
324 three libraries: <tt>mylib</tt>, <tt>LLVMSupport.a</tt> and
325 <tt>LLVMSystem.a</tt>.</p>
326 <p>Note that two different variables are use to indicate which libraries are
327 linked: <tt>USEDLIBS</tt> and <tt>LLVMLIBS</tt>. This distinction is necessary
328 to support projects. <tt>LLVMLIBS</tt> refers to the LLVM libraries found in
329 the LLVM object directory. <tt>USEDLIBS</tt> refers to the libraries built by
330 your project. In the case of building LLVM tools, <tt>USEDLIBS</tt> and
331 <tt>LLVMLIBS</tt> can be used interchangeably since the "project" is LLVM
332 itself and <tt>USEDLIBS</tt> refers to the same place as <tt>LLVMLIBS</tt>.
334 <p>Also note that there are two different ways of specifying a library: with a
335 <tt>.a</tt> suffix and without. Without the suffix, the entry refers to the
336 re-linked (.o) file which will include <em>all</em> symbols of the library.
337 This is useful, for example, to include all passes from a library of passes.
338 If the <tt>.a</tt> suffix is used then the library is linked as a searchable
339 library (with the <tt>-l</tt> option). In this case, only the symbols that are
340 unresolved <em>at that point</em> will be resolved from the library, if they
341 exist. Other (unreferenced) symbols will not be included when the <tt>.a</tt>
342 syntax is used. Note that in order to use the <tt>.a</tt> suffix, the library
343 in question must have been built with the <tt>ARCHIVE_LIBRARY</tt> option set.
347 <!-- ======================================================================= -->
348 <h4><a name="JIT">JIT Tools</a></h4>
349 <div class="doc_text">
350 <p>Many tools will want to use the JIT features of LLVM. To do this, you
351 simply specify that you want an execution 'engine', and the makefiles will
352 automatically link in the appropriate JIT for the host or an interpreter
353 if none is available:</p>
355 TOOLNAME = my_jit_tool
357 LINK_COMPONENTS = engine
359 <p>Of course, any additional libraries may be listed as other components. To
360 get a full understanding of how this changes the linker command, it is
361 recommended that you:</p>
363 cd examples/Fibonacci
368 <!-- *********************************************************************** -->
369 <h2><a name="targets">Targets Supported</a></h2>
370 <!-- *********************************************************************** -->
372 <div class="doc_text">
373 <p>This section describes each of the targets that can be built using the LLVM
374 Makefile system. Any target can be invoked from any directory but not all are
375 applicable to a given directory (e.g. "check", "dist" and "install" will
376 always operate as if invoked from the top level directory).</p>
378 <table style="text-align:left">
380 <th>Target Name</th><th>Implied Targets</th><th>Target Description</th>
382 <tr><td><a href="#all"><tt>all</tt></a></td><td></td>
383 <td>Compile the software recursively. Default target.
385 <tr><td><a href="#all-local"><tt>all-local</tt></a></td><td></td>
386 <td>Compile the software in the local directory only.
388 <tr><td><a href="#check"><tt>check</tt></a></td><td></td>
389 <td>Change to the <tt>test</tt> directory in a project and run the
392 <tr><td><a href="#check-local"><tt>check-local</tt></a></td><td></td>
393 <td>Run a local test suite. Generally this is only defined in the
394 <tt>Makefile</tt> of the project's <tt>test</tt> directory.
396 <tr><td><a href="#clean"><tt>clean</tt></a></td><td></td>
397 <td>Remove built objects recursively.
399 <tr><td><a href="#clean-local"><tt>clean-local</tt></a></td><td></td>
400 <td>Remove built objects from the local directory only.
402 <tr><td><a href="#dist"><tt>dist</tt></a></td><td>all</td>
403 <td>Prepare a source distribution tarball.
405 <tr><td><a href="#dist-check"><tt>dist-check</tt></a></td><td>all</td>
406 <td>Prepare a source distribution tarball and check that it builds.
408 <tr><td><a href="#dist-clean"><tt>dist-clean</tt></a></td><td>clean</td>
409 <td>Clean source distribution tarball temporary files.
411 <tr><td><a href="#install"><tt>install</tt></a></td><td>all</td>
412 <td>Copy built objects to installation directory.
414 <tr><td><a href="#preconditions"><tt>preconditions</tt></a></td><td>all</td>
415 <td>Check to make sure configuration and makefiles are up to date.
417 <tr><td><a href="#printvars"><tt>printvars</tt></a></td><td>all</td>
418 <td>Prints variables defined by the makefile system (for debugging).
420 <tr><td><a href="#tags"><tt>tags</tt></a></td><td></td>
421 <td>Make C and C++ tags files for emacs and vi.
423 <tr><td><a href="#uninstall"><tt>uninstall</tt></a></td><td></td>
424 <td>Remove built objects from installation directory.
429 <!-- ======================================================================= -->
430 <h3><a name="all">all (default)</a></h3>
431 <div class="doc_text">
432 <p>When you invoke <tt>make</tt> with no arguments, you are implicitly
433 instructing it to seek the "all" target (goal). This target is used for
434 building the software recursively and will do different things in different
435 directories. For example, in a <tt>lib</tt> directory, the "all" target will
436 compile source files and generate libraries. But, in a <tt>tools</tt>
437 directory, it will link libraries and generate executables.</p>
440 <!-- ======================================================================= -->
441 <h3><a name="all-local">all-local</a></h3>
442 <div class="doc_text">
443 <p>This target is the same as <a href="#all">all</a> but it operates only on
444 the current directory instead of recursively.</p>
447 <!-- ======================================================================= -->
448 <h3><a name="check">check</a></h3>
449 <div class="doc_text">
450 <p>This target can be invoked from anywhere within a project's directories
451 but always invokes the <a href="#check-local"><tt>check-local</tt></a> target
452 in the project's <tt>test</tt> directory, if it exists and has a
453 <tt>Makefile</tt>. A warning is produced otherwise. If
454 <a href="#TESTSUITE"><tt>TESTSUITE</tt></a> is defined on the <tt>make</tt>
455 command line, it will be passed down to the invocation of
456 <tt>make check-local</tt> in the <tt>test</tt> directory. The intended usage
457 for this is to assist in running specific suites of tests. If
458 <tt>TESTSUITE</tt> is not set, the implementation of <tt>check-local</tt>
459 should run all normal tests. It is up to the project to define what
460 different values for <tt>TESTSUTE</tt> will do. See the
461 <a href="TestingGuide.html">TestingGuide</a> for further details.</p>
464 <!-- ======================================================================= -->
465 <h3><a name="check-local">check-local</a></h3>
466 <div class="doc_text">
467 <p>This target should be implemented by the <tt>Makefile</tt> in the project's
468 <tt>test</tt> directory. It is invoked by the <tt>check</tt> target elsewhere.
469 Each project is free to define the actions of <tt>check-local</tt> as
470 appropriate for that project. The LLVM project itself uses dejagnu to run a
471 suite of feature and regresson tests. Other projects may choose to use
472 dejagnu or any other testing mechanism.</p>
475 <!-- ======================================================================= -->
476 <h3><a name="clean">clean</a></h3>
477 <div class="doc_text">
478 <p>This target cleans the build directory, recursively removing all things
479 that the Makefile builds. The cleaning rules have been made guarded so they
480 shouldn't go awry (via <tt>rm -f $(UNSET_VARIABLE)/*</tt> which will attempt
481 to erase the entire directory structure.</p>
484 <!-- ======================================================================= -->
485 <h3><a name="clean-local">clean-local</a></h3>
486 <div class="doc_text">
487 <p>This target does the same thing as <tt>clean</tt> but only for the current
488 (local) directory.</p>
491 <!-- ======================================================================= -->
492 <h3><a name="dist">dist</a></h3>
493 <div class="doc_text">
494 <p>This target builds a distribution tarball. It first builds the entire
495 project using the <tt>all</tt> target and then tars up the necessary files and
496 compresses it. The generated tarball is sufficient for a casual source
497 distribution, but probably not for a release (see <tt>dist-check</tt>).</p>
500 <!-- ======================================================================= -->
501 <h3><a name="dist-check">dist-check</a></h3>
502 <div class="doc_text">
503 <p>This target does the same thing as the <tt>dist</tt> target but also checks
504 the distribution tarball. The check is made by unpacking the tarball to a new
505 directory, configuring it, building it, installing it, and then verifying that
506 the installation results are correct (by comparing to the original build).
507 This target can take a long time to run but should be done before a release
508 goes out to make sure that the distributed tarball can actually be built into
509 a working release.</p>
512 <!-- ======================================================================= -->
513 <h3><a name="dist-clean">dist-clean</a></h3>
514 <div class="doc_text">
515 <p>This is a special form of the <tt>clean</tt> clean target. It performs a
516 normal <tt>clean</tt> but also removes things pertaining to building the
520 <!-- ======================================================================= -->
521 <h3><a name="install">install</a></h3>
522 <div class="doc_text">
523 <p>This target finalizes shared objects and executables and copies all
524 libraries, headers, executables and documentation to the directory given
525 with the <tt>--prefix</tt> option to <tt>configure</tt>. When completed,
526 the prefix directory will have everything needed to <b>use</b> LLVM. </p>
527 <p>The LLVM makefiles can generate complete <b>internal</b> documentation
528 for all the classes by using <tt>doxygen</tt>. By default, this feature is
529 <b>not</b> enabled because it takes a long time and generates a massive
530 amount of data (>100MB). If you want this feature, you must configure LLVM
531 with the --enable-doxygen switch and ensure that a modern version of doxygen
532 (1.3.7 or later) is available in your <tt>PATH</tt>. You can download
534 <a href="http://www.stack.nl/~dimitri/doxygen/download.html#latestsrc">
538 <!-- ======================================================================= -->
539 <h3><a name="preconditions">preconditions</a></h3>
540 <div class="doc_text">
541 <p>This utility target checks to see if the <tt>Makefile</tt> in the object
542 directory is older than the <tt>Makefile</tt> in the source directory and
543 copies it if so. It also reruns the <tt>configure</tt> script if that needs to
544 be done and rebuilds the <tt>Makefile.config</tt> file similarly. Users may
545 overload this target to ensure that sanity checks are run <em>before</em> any
546 building of targets as all the targets depend on <tt>preconditions</tt>.</p>
549 <!-- ======================================================================= -->
550 <h3><a name="printvars">printvars</a></h3>
551 <div class="doc_text">
552 <p>This utility target just causes the LLVM makefiles to print out some of
553 the makefile variables so that you can double check how things are set. </p>
556 <!-- ======================================================================= -->
557 <h3><a name="reconfigure">reconfigure</a></h3>
558 <div class="doc_text">
559 <p>This utility target will force a reconfigure of LLVM or your project. It
560 simply runs <tt>$(PROJ_OBJ_ROOT)/config.status --recheck</tt> to rerun the
561 configuration tests and rebuild the configured files. This isn't generally
562 useful as the makefiles will reconfigure themselves whenever its necessary.
566 <!-- ======================================================================= -->
567 <h3><a name="spotless">spotless</a></h3>
568 <div class="doc_text">
569 <p>This utility target, only available when <tt>$(PROJ_OBJ_ROOT)</tt> is not
570 the same as <tt>$(PROJ_SRC_ROOT)</tt>, will completely clean the
571 <tt>$(PROJ_OBJ_ROOT)</tt> directory by removing its content entirely and
572 reconfiguring the directory. This returns the <tt>$(PROJ_OBJ_ROOT)</tt>
573 directory to a completely fresh state. All content in the directory except
574 configured files and top-level makefiles will be lost.</p>
575 <div class="doc_warning"><p>Use with caution.</p></div>
578 <!-- ======================================================================= -->
579 <h3><a name="tags">tags</a></h3>
580 <div class="doc_text">
581 <p>This target will generate a <tt>TAGS</tt> file in the top-level source
582 directory. It is meant for use with emacs, XEmacs, or ViM. The TAGS file
583 provides an index of symbol definitions so that the editor can jump you to the
584 definition quickly. </p>
587 <!-- ======================================================================= -->
588 <h3><a name="uninstall">uninstall</a></h3>
589 <div class="doc_text">
590 <p>This target is the opposite of the <tt>install</tt> target. It removes the
591 header, library and executable files from the installation directories. Note
592 that the directories themselves are not removed because it is not guaranteed
593 that LLVM is the only thing installing there (e.g. --prefix=/usr).</p>
596 <!-- *********************************************************************** -->
597 <h2><a name="variables">Variables</a></h2>
598 <!-- *********************************************************************** -->
599 <div class="doc_text">
600 <p>Variables are used to tell the LLVM Makefile System what to do and to
601 obtain information from it. Variables are also used internally by the LLVM
602 Makefile System. Variable names that contain only the upper case alphabetic
603 letters and underscore are intended for use by the end user. All other
604 variables are internal to the LLVM Makefile System and should not be relied
605 upon nor modified. The sections below describe how to use the LLVM Makefile
609 <!-- ======================================================================= -->
610 <h3><a name="setvars">Control Variables</a></h3>
611 <div class="doc_text">
612 <p>Variables listed in the table below should be set <em>before</em> the
613 inclusion of <a href="#Makefile.common"><tt>$(LEVEL)/Makefile.common</tt></a>.
614 These variables provide input to the LLVM make system that tell it what to do
615 for the current directory.</p>
617 <dt><a name="BUILD_ARCHIVE"><tt>BUILD_ARCHIVE</tt></a></dt>
618 <dd>If set to any value, causes an archive (.a) library to be built.</dd>
619 <dt><a name="BUILT_SOURCES"><tt>BUILT_SOURCES</tt></a></dt>
620 <dd>Specifies a set of source files that are generated from other source
621 files. These sources will be built before any other target processing to
622 ensure they are present.</dd>
623 <dt><a name="BYTECODE_LIBRARY"><tt>BYTECODE_LIBRARY</tt></a></dt>
624 <dd>If set to any value, causes a bitcode library (.bc) to be built.</dd>
625 <dt><a name="CONFIG_FILES"><tt>CONFIG_FILES</tt></a></dt>
626 <dd>Specifies a set of configuration files to be installed.</dd>
627 <dt><a name="DEBUG_SYMBOLS"><tt>DEBUG_SYMBOLS</tt></a></dt>
628 <dd>If set to any value, causes the build to include debugging
629 symbols even in optimized objects, libraries and executables. This
630 alters the flags specified to the compilers and linkers. Debugging
631 isn't fun in an optimized build, but it is possible.</dd>
632 <dt><a name="DIRS"><tt>DIRS</tt></a></dt>
633 <dd>Specifies a set of directories, usually children of the current
634 directory, that should also be made using the same goal. These directories
635 will be built serially.</dd>
636 <dt><a name="DISABLE_AUTO_DEPENDENCIES"><tt>DISABLE_AUTO_DEPENDENCIES</tt></a></dt>
637 <dd>If set to any value, causes the makefiles to <b>not</b> automatically
638 generate dependencies when running the compiler. Use of this feature is
639 discouraged and it may be removed at a later date.</dd>
640 <dt><a name="ENABLE_OPTIMIZED"><tt>ENABLE_OPTIMIZED</tt></a></dt>
641 <dd>If set to 1, causes the build to generate optimized objects,
642 libraries and executables. This alters the flags specified to the compilers
643 and linkers. Generally debugging won't be a fun experience with an optimized
645 <dt><a name="ENABLE_PROFILING"><tt>ENABLE_PROFILING</tt></a></dt>
646 <dd>If set to 1, causes the build to generate both optimized and
647 profiled objects, libraries and executables. This alters the flags specified
648 to the compilers and linkers to ensure that profile data can be collected
649 from the tools built. Use the <tt>gprof</tt> tool to analyze the output from
650 the profiled tools (<tt>gmon.out</tt>).</dd>
651 <dt><a name="DISABLE_ASSERTIONS"><tt>DISABLE_ASSERTIONS</tt></a></dt>
652 <dd>If set to 1, causes the build to disable assertions, even if
653 building a debug or profile build. This will exclude all assertion check
654 code from the build. LLVM will execute faster, but with little help when
655 things go wrong.</dd>
656 <dt><a name="EXPERIMENTAL_DIRS"><tt>EXPERIMENTAL_DIRS</tt></a></dt>
657 <dd>Specify a set of directories that should be built, but if they fail, it
658 should not cause the build to fail. Note that this should only be used
659 temporarily while code is being written.</dd>
660 <dt><a name="EXPORTED_SYMBOL_FILE"><tt>EXPORTED_SYMBOL_FILE</tt></a></dt>
661 <dd>Specifies the name of a single file that contains a list of the
662 symbols to be exported by the linker. One symbol per line.</dd>
663 <dt><a name="EXPORTED_SYMBOL_LIST"><tt>EXPORTED_SYMBOL_LIST</tt></a></dt>
664 <dd>Specifies a set of symbols to be exported by the linker.</dd>
665 <dt><a name="EXTRA_DIST"><tt>EXTRA_DIST</tt></a></dt>
666 <dd>Specifies additional files that should be distributed with LLVM. All
667 source files, all built sources, all Makefiles, and most documentation files
668 will be automatically distributed. Use this variable to distribute any
669 files that are not automatically distributed.</dd>
670 <dt><a name="KEEP_SYMBOLS"><tt>KEEP_SYMBOLS</tt></a></dt>
671 <dd>If set to any value, specifies that when linking executables the
672 makefiles should retain debug symbols in the executable. Normally, symbols
673 are stripped from the executable.</dd>
674 <dt><a name="LEVEL"><tt>LEVEL</tt></a><small>(required)</small></dt>
675 <dd>Specify the level of nesting from the top level. This variable must be
676 set in each makefile as it is used to find the top level and thus the other
678 <dt><a name="LIBRARYNAME"><tt>LIBRARYNAME</tt></a></dt>
679 <dd>Specify the name of the library to be built. (Required For
681 <dt><a name="LINK_COMPONENTS"><tt>LINK_COMPONENTS</tt></a></dt>
682 <dd>When specified for building a tool, the value of this variable will be
683 passed to the <tt>llvm-config</tt> tool to generate a link line for the
684 tool. Unlike <tt>USEDLIBS</tt> and <tt>LLVMLIBS</tt>, not all libraries need
685 to be specified. The <tt>llvm-config</tt> tool will figure out the library
686 dependencies and add any libraries that are needed. The <tt>USEDLIBS</tt>
687 variable can still be used in conjunction with <tt>LINK_COMPONENTS</tt> so
688 that additional project-specific libraries can be linked with the LLVM
689 libraries specified by <tt>LINK_COMPONENTS</tt></dd>
690 <dt><a name="LINK_LIBS_IN_SHARED"><tt>LINK_LIBS_IN_SHARED</tt></a></dt>
691 <dd>By default, shared library linking will ignore any libraries specified
692 with the <a href="LLVMLIBS">LLVMLIBS</a> or <a href="USEDLIBS">USEDLIBS</a>.
693 This prevents shared libs from including things that will be in the LLVM
694 tool the shared library will be loaded into. However, sometimes it is useful
695 to link certain libraries into your shared library and this option enables
697 <dt><a name="LLVMLIBS"><tt>LLVMLIBS</tt></a></dt>
698 <dd>Specifies the set of libraries from the LLVM $(ObjDir) that will be
699 linked into the tool or library.</dd>
700 <dt><a name="LOADABLE_MODULE"><tt>LOADABLE_MODULE</tt></a></dt>
701 <dd>If set to any value, causes the shared library being built to also be
702 a loadable module. Loadable modules can be opened with the dlopen() function
703 and searched with dlsym (or the operating system's equivalent). Note that
704 setting this variable without also setting <tt>SHARED_LIBRARY</tt> will have
706 <dt><a name="MODULE_NAME"><tt>MODULE_NAME</tt></a></dt>
707 <dd>Specifies the name of a bitcode module to be created. A bitcode
708 module can be specified in conjunction with other kinds of library builds
709 or by itself. It constructs from the sources a single linked bitcode
711 <dt><a name="NO_INSTALL"><tt>NO_INSTALL</tt></a></dt>
712 <dd>Specifies that the build products of the directory should not be
713 installed but should be built even if the <tt>install</tt> target is given.
714 This is handy for directories that build libraries or tools that are only
715 used as part of the build process, such as code generators (e.g.
716 <tt>tblgen</tt>).</dd>
717 <dt><a name="OPTIONAL_DIRS"><tt>OPTIONAL_DIRS</tt></a></dt>
718 <dd>Specify a set of directories that may be built, if they exist, but its
719 not an error for them not to exist.</dd>
720 <dt><a name="PARALLEL_DIRS"><tt>PARALLEL_DIRS</tt></a></dt>
721 <dd>Specify a set of directories to build recursively and in parallel if
722 the -j option was used with <tt>make</tt>.</dd>
723 <dt><a name="SHARED_LIBRARY"><tt>SHARED_LIBRARY</tt></a></dt>
724 <dd>If set to any value, causes a shared library (.so) to be built in
725 addition to any other kinds of libraries. Note that this option will cause
726 all source files to be built twice: once with options for position
727 independent code and once without. Use it only where you really need a
729 <dt><a name="SOURCES"><tt>SOURCES</tt><small>(optional)</small></a></dt>
730 <dd>Specifies the list of source files in the current directory to be
731 built. Source files of any type may be specified (programs, documentation,
732 config files, etc.). If not specified, the makefile system will infer the
733 set of source files from the files present in the current directory.</dd>
734 <dt><a name="SUFFIXES"><tt>SUFFIXES</tt></a></dt>
735 <dd>Specifies a set of filename suffixes that occur in suffix match rules.
736 Only set this if your local <tt>Makefile</tt> specifies additional suffix
738 <dt><a name="TARGET"><tt>TARGET</tt></a></dt>
739 <dd>Specifies the name of the LLVM code generation target that the
740 current directory builds. Setting this variable enables additional rules to
741 build <tt>.inc</tt> files from <tt>.td</tt> files. </dd>
742 <dt><a name="TESTSUITE"><tt>TESTSUITE</tt></a></dt>
743 <dd>Specifies the directory of tests to run in <tt>llvm/test</tt>.</dd>
744 <dt><a name="TOOLNAME"><tt>TOOLNAME</tt></a></dt>
745 <dd>Specifies the name of the tool that the current directory should
747 <dt><a name="TOOL_VERBOSE"><tt>TOOL_VERBOSE</tt></a></dt>
748 <dd>Implies VERBOSE and also tells each tool invoked to be verbose. This is
749 handy when you're trying to see the sub-tools invoked by each tool invoked
750 by the makefile. For example, this will pass <tt>-v</tt> to the GCC
751 compilers which causes it to print out the command lines it uses to invoke
752 sub-tools (compiler, assembler, linker).</dd>
753 <dt><a name="USEDLIBS"><tt>USEDLIBS</tt></a></dt>
754 <dd>Specifies the list of project libraries that will be linked into the
755 tool or library.</dd>
756 <dt><a name="VERBOSE"><tt>VERBOSE</tt></a></dt>
757 <dd>Tells the Makefile system to produce detailed output of what it is doing
758 instead of just summary comments. This will generate a LOT of output.</dd>
762 <!-- ======================================================================= -->
763 <h3><a name="overvars">Override Variables</a></h3>
764 <div class="doc_text">
765 <p>Override variables can be used to override the default
766 values provided by the LLVM makefile system. These variables can be set in
769 <li>In the environment (e.g. setenv, export) -- not recommended.</li>
770 <li>On the <tt>make</tt> command line -- recommended.</li>
771 <li>On the <tt>configure</tt> command line</li>
772 <li>In the Makefile (only <em>after</em> the inclusion of <a
773 href="#Makefile.common"><tt>$(LEVEL)/Makefile.common</tt></a>).</li>
775 <p>The override variables are given below:</p>
777 <dt><a name="AR"><tt>AR</tt></a> <small>(defaulted)</small></dt>
778 <dd>Specifies the path to the <tt>ar</tt> tool.</dd>
779 <dt><a name="PROJ_OBJ_DIR"><tt>PROJ_OBJ_DIR</tt></a></dt>
780 <dd>The directory into which the products of build rules will be placed.
781 This might be the same as
782 <a href="#PROJ_SRC_DIR"><tt>PROJ_SRC_DIR</tt></a> but typically is
784 <dt><a name="PROJ_SRC_DIR"><tt>PROJ_SRC_DIR</tt></a></dt>
785 <dd>The directory which contains the source files to be built.</dd>
786 <dt><a name="BUILD_EXAMPLES"><tt>BUILD_EXAMPLES</tt></a></dt>
787 <dd>If set to 1, build examples in <tt>examples</tt> and (if building
788 Clang) <tt>tools/clang/examples</tt> directories.</dd>
789 <dt><a name="BZIP2"><tt>BZIP2</tt></a><small>(configured)</small></dt>
790 <dd>The path to the <tt>bzip2</tt> tool.</dd>
791 <dt><a name="CC"><tt>CC</tt></a><small>(configured)</small></dt>
792 <dd>The path to the 'C' compiler.</dd>
793 <dt><a name="CFLAGS"><tt>CFLAGS</tt></a></dt>
794 <dd>Additional flags to be passed to the 'C' compiler.</dd>
795 <dt><a name="CXX"><tt>CXX</tt></a></dt>
796 <dd>Specifies the path to the C++ compiler.</dd>
797 <dt><a name="CXXFLAGS"><tt>CXXFLAGS</tt></a></dt>
798 <dd>Additional flags to be passed to the C++ compiler.</dd>
799 <dt><a name="DATE"><tt>DATE<small>(configured)</small></tt></a></dt>
800 <dd>Specifies the path to the <tt>date</tt> program or any program that can
801 generate the current date and time on its standard output</dd>
802 <dt><a name="DOT"><tt>DOT</tt></a><small>(configured)</small></dt>
803 <dd>Specifies the path to the <tt>dot</tt> tool or <tt>false</tt> if there
805 <dt><a name="ECHO"><tt>ECHO</tt></a><small>(configured)</small></dt>
806 <dd>Specifies the path to the <tt>echo</tt> tool for printing output.</dd>
807 <dt><a name="EXEEXT"><tt>EXEEXT</tt></a><small>(configured)</small></dt>
808 <dd>Provides the extension to be used on executables built by the makefiles.
809 The value may be empty on platforms that do not use file extensions for
810 executables (e.g. Unix).</dd>
811 <dt><a name="INSTALL"><tt>INSTALL</tt></a><small>(configured)</small></dt>
812 <dd>Specifies the path to the <tt>install</tt> tool.</dd>
813 <dt><a name="LDFLAGS"><tt>LDFLAGS</tt></a><small>(configured)</small></dt>
814 <dd>Allows users to specify additional flags to pass to the linker.</dd>
815 <dt><a name="LIBS"><tt>LIBS</tt></a><small>(configured)</small></dt>
816 <dd>The list of libraries that should be linked with each tool.</dd>
817 <dt><a name="LIBTOOL"><tt>LIBTOOL</tt></a><small>(configured)</small></dt>
818 <dd>Specifies the path to the <tt>libtool</tt> tool. This tool is renamed
819 <tt>mklib</tt> by the <tt>configure</tt> script and always located in the
820 <dt><a name="LLVMAS"><tt>LLVMAS</tt></a><small>(defaulted)</small></dt>
821 <dd>Specifies the path to the <tt>llvm-as</tt> tool.</dd>
822 <dt><a name="LLVMCC"><tt>LLVMCC</tt></a></dt>
823 <dd>Specifies the path to the LLVM capable compiler.</dd>
824 <dt><a name="LLVMCXX"><tt>LLVMCXX</tt></a></dt>
825 <dd>Specifies the path to the LLVM C++ capable compiler.</dd>
826 <dt><a name="LLVMGCC"><tt>LLVMGCC</tt></a><small>(defaulted)</small></dt>
827 <dd>Specifies the path to the LLVM version of the GCC 'C' Compiler</dd>
828 <dt><a name="LLVMGXX"><tt>LLVMGXX</tt></a><small>(defaulted)</small></dt>
829 <dd>Specifies the path to the LLVM version of the GCC C++ Compiler</dd>
830 <dt><a name="LLVMLD"><tt>LLVMLD</tt></a><small>(defaulted)</small></dt>
831 <dd>Specifies the path to the LLVM bitcode linker tool</dd>
832 <dt><a name="LLVM_OBJ_ROOT"><tt>LLVM_OBJ_ROOT</tt></a><small>(configured)
834 <dd>Specifies the top directory into which the output of the build is
836 <dt><a name="LLVM_SRC_ROOT"><tt>LLVM_SRC_ROOT</tt></a><small>(configured)
838 <dd>Specifies the top directory in which the sources are found.</dd>
839 <dt><a name="LLVM_TARBALL_NAME"><tt>LLVM_TARBALL_NAME</tt></a>
840 <small>(configured)</small></dt>
841 <dd>Specifies the name of the distribution tarball to create. This is
842 configured from the name of the project and its version number.</dd>
843 <dt><a name="MKDIR"><tt>MKDIR</tt></a><small>(defaulted)</small></dt>
844 <dd>Specifies the path to the <tt>mkdir</tt> tool that creates
846 <dt><a name="ONLY_TOOLS"><tt>ONLY_TOOLS</tt></a></dt>
847 <dd>If set, specifies the list of tools to build.</dd>
848 <dt><a name="PLATFORMSTRIPOPTS"><tt>PLATFORMSTRIPOPTS</tt></a></dt>
849 <dd>The options to provide to the linker to specify that a stripped (no
850 symbols) executable should be built.</dd>
851 <dt><a name="RANLIB"><tt>RANLIB</tt></a><small>(defaulted)</small></dt>
852 <dd>Specifies the path to the <tt>ranlib</tt> tool.</dd>
853 <dt><a name="RM"><tt>RM</tt></a><small>(defaulted)</small></dt>
854 <dd>Specifies the path to the <tt>rm</tt> tool.</dd>
855 <dt><a name="SED"><tt>SED</tt></a><small>(defaulted)</small></dt>
856 <dd>Specifies the path to the <tt>sed</tt> tool.</dd>
857 <dt><a name="SHLIBEXT"><tt>SHLIBEXT</tt></a><small>(configured)</small></dt>
858 <dd>Provides the filename extension to use for shared libraries.</dd>
859 <dt><a name="TBLGEN"><tt>TBLGEN</tt></a><small>(defaulted)</small></dt>
860 <dd>Specifies the path to the <tt>tblgen</tt> tool.</dd>
861 <dt><a name="TAR"><tt>TAR</tt></a><small>(defaulted)</small></dt>
862 <dd>Specifies the path to the <tt>tar</tt> tool.</dd>
863 <dt><a name="ZIP"><tt>ZIP</tt></a><small>(defaulted)</small></dt>
864 <dd>Specifies the path to the <tt>zip</tt> tool.</dd>
868 <!-- ======================================================================= -->
869 <h3><a name="getvars">Readable Variables</a></h3>
870 <div class="doc_text">
871 <p>Variables listed in the table below can be used by the user's Makefile but
872 should not be changed. Changing the value will generally cause the build to go
873 wrong, so don't do it.</p>
875 <dt><a name="bindir"><tt>bindir</tt></a></dt>
876 <dd>The directory into which executables will ultimately be installed. This
877 value is derived from the <tt>--prefix</tt> option given to
878 <tt>configure</tt>.</dd>
879 <dt><a name="BuildMode"><tt>BuildMode</tt></a></dt>
880 <dd>The name of the type of build being performed: Debug, Release, or
882 <dt><a name="bitcode_libdir"><tt>bytecode_libdir</tt></a></dt>
883 <dd>The directory into which bitcode libraries will ultimately be
884 installed. This value is derived from the <tt>--prefix</tt> option given to
885 <tt>configure</tt>.</dd>
886 <dt><a name="ConfigureScriptFLAGS"><tt>ConfigureScriptFLAGS</tt></a></dt>
887 <dd>Additional flags given to the <tt>configure</tt> script when
889 <dt><a name="DistDir"><tt>DistDir</tt></a></dt>
890 <dd>The <em>current</em> directory for which a distribution copy is being
892 <dt><a name="Echo"><tt>Echo</tt></a></dt>
893 <dd>The LLVM Makefile System output command. This provides the
894 <tt>llvm[n]</tt> prefix and starts with @ so the command itself is not
895 printed by <tt>make</tt>.</dd>
896 <dt><a name="EchoCmd"><tt>EchoCmd</tt></a></dt>
897 <dd> Same as <a href="#Echo"><tt>Echo</tt></a> but without the leading @.
899 <dt><a name="includedir"><tt>includedir</tt></a></dt>
900 <dd>The directory into which include files will ultimately be installed.
901 This value is derived from the <tt>--prefix</tt> option given to
902 <tt>configure</tt>.</dd>
903 <dt><a name="libdir"><tt>libdir</tt></a></dt><dd></dd>
904 <dd>The directory into which native libraries will ultimately be installed.
905 This value is derived from the <tt>--prefix</tt> option given to
906 <tt>configure</tt>.</dd>
907 <dt><a name="LibDir"><tt>LibDir</tt></a></dt>
908 <dd>The configuration specific directory into which libraries are placed
909 before installation.</dd>
910 <dt><a name="MakefileConfig"><tt>MakefileConfig</tt></a></dt>
911 <dd>Full path of the <tt>Makefile.config</tt> file.</dd>
912 <dt><a name="MakefileConfigIn"><tt>MakefileConfigIn</tt></a></dt>
913 <dd>Full path of the <tt>Makefile.config.in</tt> file.</dd>
914 <dt><a name="ObjDir"><tt>ObjDir</tt></a></dt>
915 <dd>The configuration and directory specific directory where build objects
916 (compilation results) are placed.</dd>
917 <dt><a name="SubDirs"><tt>SubDirs</tt></a></dt>
918 <dd>The complete list of sub-directories of the current directory as
919 specified by other variables.</dd>
920 <dt><a name="Sources"><tt>Sources</tt></a></dt>
921 <dd>The complete list of source files.</dd>
922 <dt><a name="sysconfdir"><tt>sysconfdir</tt></a></dt>
923 <dd>The directory into which configuration files will ultimately be
924 installed. This value is derived from the <tt>--prefix</tt> option given to
925 <tt>configure</tt>.</dd>
926 <dt><a name="ToolDir"><tt>ToolDir</tt></a></dt>
927 <dd>The configuration specific directory into which executables are placed
928 before they are installed.</dd>
929 <dt><a name="TopDistDir"><tt>TopDistDir</tt></a></dt>
930 <dd>The top most directory into which the distribution files are copied.
932 <dt><a name="Verb"><tt>Verb</tt></a></dt>
933 <dd>Use this as the first thing on your build script lines to enable or
934 disable verbose mode. It expands to either an @ (quiet mode) or nothing
935 (verbose mode). </dd>
939 <!-- ======================================================================= -->
940 <h3><a name="intvars">Internal Variables</a></h3>
941 <div class="doc_text">
942 <p>Variables listed below are used by the LLVM Makefile System
943 and considered internal. You should not use these variables under any
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