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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 <!-- *********************************************************************** -->
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 <!-- *********************************************************************** -->
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>
112 <!-- ======================================================================= -->
113 <h3><a name="projects">Projects</a></h3>
115 <p>The LLVM Makefile System is quite generous. It not only builds its own
116 software, but it can build yours too. Built into the system is knowledge of
117 the <tt>llvm/projects</tt> directory. Any directory under <tt>projects</tt>
118 that has both a <tt>configure</tt> script and a <tt>Makefile</tt> is assumed
119 to be a project that uses the LLVM Makefile system. Building software that
120 uses LLVM does not require the LLVM Makefile System nor even placement in the
121 <tt>llvm/projects</tt> directory. However, doing so will allow your project
122 to get up and running quickly by utilizing the built-in features that are used
123 to compile LLVM. LLVM compiles itself using the same features of the makefile
124 system as used for projects.</p>
125 <p>For complete details on setting up your projects configuration, simply
126 mimic the <tt>llvm/projects/sample</tt> project or for further details,
127 consult the <a href="Projects.html">Projects.html</a> page.</p>
130 <!-- ======================================================================= -->
131 <h3><a name="varvalues">Variable Values</a></h3>
133 <p>To use the makefile system, you simply create a file named
134 <tt>Makefile</tt> in your directory and declare values for certain variables.
135 The variables and values that you select determine what the makefile system
136 will do. These variables enable rules and processing in the makefile system
137 that automatically Do The Right Thing™.
140 <!-- ======================================================================= -->
141 <h3><a name="including">Including Makefiles</a></h3>
143 <p>Setting variables alone is not enough. You must include into your Makefile
144 additional files that provide the rules of the LLVM Makefile system. The
145 various files involved are described in the sections that follow.</p>
147 <!-- ======================================================================= -->
148 <h4><a name="Makefile">Makefile</a></h4>
150 <p>Each directory to participate in the build needs to have a file named
151 <tt>Makefile</tt>. This is the file first read by <tt>make</tt>. It has three
154 <li><a href="#setvars">Settable Variables</a> - Required that must be set
156 <li><a href="#Makefile.common">include <tt>$(LEVEL)/Makefile.common</tt></a>
157 - include the LLVM Makefile system.
158 <li><a href="#overvars">Override Variables</a> - Override variables set by
159 the LLVM Makefile system.
163 <!-- ======================================================================= -->
164 <h4><a name="Makefile.common">Makefile.common</a></h4>
166 <p>Every project must have a <tt>Makefile.common</tt> file at its top source
167 directory. This file serves three purposes:</p>
169 <li>It includes the project's configuration makefile to obtain values
170 determined by the <tt>configure</tt> script. This is done by including the
171 <a href="#Makefile.config"><tt>$(LEVEL)/Makefile.config</tt></a> file.</li>
172 <li>It specifies any other (static) values that are needed throughout the
173 project. Only values that are used in all or a large proportion of the
174 project's directories should be placed here.</li>
175 <li>It includes the standard rules for the LLVM Makefile system,
176 <a href="#Makefile.rules"><tt>$(LLVM_SRC_ROOT)/Makefile.rules</tt></a>.
177 This file is the "guts" of the LLVM Makefile system.</li>
181 <!-- ======================================================================= -->
182 <h4><a name="Makefile.config">Makefile.config</a></h4>
184 <p>Every project must have a <tt>Makefile.config</tt> at the top of its
185 <em>build</em> directory. This file is <b>generated</b> by the
186 <tt>configure</tt> script from the pattern provided by the
187 <tt>Makefile.config.in</tt> file located at the top of the project's
188 <em>source</em> directory. The contents of this file depend largely on what
189 configuration items the project uses, however most projects can get what they
190 need by just relying on LLVM's configuration found in
191 <tt>$(LLVM_OBJ_ROOT)/Makefile.config</tt>.
194 <!-- ======================================================================= -->
195 <h4><a name="Makefile.rules">Makefile.rules</a></h4>
197 <p>This file, located at <tt>$(LLVM_SRC_ROOT)/Makefile.rules</tt> is the heart
198 of the LLVM Makefile System. It provides all the logic, dependencies, and
199 rules for building the targets supported by the system. What it does largely
200 depends on the values of <tt>make</tt> <a href="#variables">variables</a> that
201 have been set <em>before</em> <tt>Makefile.rules</tt> is included.
206 <!-- ======================================================================= -->
207 <h3><a name="Comments">Comments</a></h3>
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>
218 <!-- *********************************************************************** -->
219 <h2><a name="tutorial">Tutorial</a></h2>
220 <!-- *********************************************************************** -->
222 <p>This section provides some examples of the different kinds of modules you
223 can build with the LLVM makefile system. In general, each directory you
224 provide will build a single object although that object may be composed of
225 additionally compiled components.</p>
227 <!-- ======================================================================= -->
228 <h3><a name="libraries">Libraries</a></h3>
230 <p>Only a few variable definitions are needed to build a regular library.
231 Normally, the makefile system will build all the software into a single
232 <tt>libname.o</tt> (pre-linked) object. This means the library is not
233 searchable and that the distinction between compilation units has been
234 dissolved. Optionally, you can ask for a shared library (.so) or archive
235 library (.a) built. Archive libraries are the default. For example:</p>
241 <p>says to build a library named "mylib" with both a shared library
242 (<tt>mylib.so</tt>) and an archive library (<tt>mylib.a</tt>) version. The
244 libraries produced will be the same, they are just constructed differently.
245 Note that you normally do not need to specify the sources involved. The LLVM
246 Makefile system will infer the source files from the contents of the source
248 <p>The <tt>LOADABLE_MODULE=1</tt> directive can be used in conjunction with
249 <tt>SHARED_LIBRARY=1</tt> to indicate that the resulting shared library should
250 be openable with the <tt>dlopen</tt> function and searchable with the
251 <tt>dlsym</tt> function (or your operating system's equivalents). While this
252 isn't strictly necessary on Linux and a few other platforms, it is required
253 on systems like HP-UX and Darwin. You should use <tt>LOADABLE_MODULE</tt> for
254 any shared library that you intend to be loaded into an tool via the
255 <tt>-load</tt> option. See the
256 <a href="WritingAnLLVMPass.html#makefile">WritingAnLLVMPass.html</a> document
257 for an example of why you might want to do this.
259 <!-- ======================================================================= -->
260 <h4><a name="BCModules">Bitcode Modules</a></h4>
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>
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>
314 <!-- ======================================================================= -->
315 <h3><a name="tools">Tools</a></h3>
317 <p>For building executable programs (tools), you must provide the name of the
318 tool and the names of the libraries you wish to link with the tool. For
323 LINK_COMPONENTS = support system
325 <p>says that we are to build a tool name <tt>mytool</tt> and that it requires
326 three libraries: <tt>mylib</tt>, <tt>LLVMSupport.a</tt> and
327 <tt>LLVMSystem.a</tt>.</p>
328 <p>Note that two different variables are use to indicate which libraries are
329 linked: <tt>USEDLIBS</tt> and <tt>LLVMLIBS</tt>. This distinction is necessary
330 to support projects. <tt>LLVMLIBS</tt> refers to the LLVM libraries found in
331 the LLVM object directory. <tt>USEDLIBS</tt> refers to the libraries built by
332 your project. In the case of building LLVM tools, <tt>USEDLIBS</tt> and
333 <tt>LLVMLIBS</tt> can be used interchangeably since the "project" is LLVM
334 itself and <tt>USEDLIBS</tt> refers to the same place as <tt>LLVMLIBS</tt>.
336 <p>Also note that there are two different ways of specifying a library: with a
337 <tt>.a</tt> suffix and without. Without the suffix, the entry refers to the
338 re-linked (.o) file which will include <em>all</em> symbols of the library.
339 This is useful, for example, to include all passes from a library of passes.
340 If the <tt>.a</tt> suffix is used then the library is linked as a searchable
341 library (with the <tt>-l</tt> option). In this case, only the symbols that are
342 unresolved <em>at that point</em> will be resolved from the library, if they
343 exist. Other (unreferenced) symbols will not be included when the <tt>.a</tt>
344 syntax is used. Note that in order to use the <tt>.a</tt> suffix, the library
345 in question must have been built with the <tt>ARCHIVE_LIBRARY</tt> option set.
348 <!-- ======================================================================= -->
349 <h4><a name="JIT">JIT Tools</a></h4>
351 <p>Many tools will want to use the JIT features of LLVM. To do this, you
352 simply specify that you want an execution 'engine', and the makefiles will
353 automatically link in the appropriate JIT for the host or an interpreter
354 if none is available:</p>
356 TOOLNAME = my_jit_tool
358 LINK_COMPONENTS = engine
360 <p>Of course, any additional libraries may be listed as other components. To
361 get a full understanding of how this changes the linker command, it is
362 recommended that you:</p>
364 cd examples/Fibonacci
373 <!-- *********************************************************************** -->
374 <h2><a name="targets">Targets Supported</a></h2>
375 <!-- *********************************************************************** -->
378 <p>This section describes each of the targets that can be built using the LLVM
379 Makefile system. Any target can be invoked from any directory but not all are
380 applicable to a given directory (e.g. "check", "dist" and "install" will
381 always operate as if invoked from the top level directory).</p>
383 <table style="text-align:left">
385 <th>Target Name</th><th>Implied Targets</th><th>Target Description</th>
387 <tr><td><a href="#all"><tt>all</tt></a></td><td></td>
388 <td>Compile the software recursively. Default target.
390 <tr><td><a href="#all-local"><tt>all-local</tt></a></td><td></td>
391 <td>Compile the software in the local directory only.
393 <tr><td><a href="#check"><tt>check</tt></a></td><td></td>
394 <td>Change to the <tt>test</tt> directory in a project and run the
397 <tr><td><a href="#check-local"><tt>check-local</tt></a></td><td></td>
398 <td>Run a local test suite. Generally this is only defined in the
399 <tt>Makefile</tt> of the project's <tt>test</tt> directory.
401 <tr><td><a href="#clean"><tt>clean</tt></a></td><td></td>
402 <td>Remove built objects recursively.
404 <tr><td><a href="#clean-local"><tt>clean-local</tt></a></td><td></td>
405 <td>Remove built objects from the local directory only.
407 <tr><td><a href="#dist"><tt>dist</tt></a></td><td>all</td>
408 <td>Prepare a source distribution tarball.
410 <tr><td><a href="#dist-check"><tt>dist-check</tt></a></td><td>all</td>
411 <td>Prepare a source distribution tarball and check that it builds.
413 <tr><td><a href="#dist-clean"><tt>dist-clean</tt></a></td><td>clean</td>
414 <td>Clean source distribution tarball temporary files.
416 <tr><td><a href="#install"><tt>install</tt></a></td><td>all</td>
417 <td>Copy built objects to installation directory.
419 <tr><td><a href="#preconditions"><tt>preconditions</tt></a></td><td>all</td>
420 <td>Check to make sure configuration and makefiles are up to date.
422 <tr><td><a href="#printvars"><tt>printvars</tt></a></td><td>all</td>
423 <td>Prints variables defined by the makefile system (for debugging).
425 <tr><td><a href="#tags"><tt>tags</tt></a></td><td></td>
426 <td>Make C and C++ tags files for emacs and vi.
428 <tr><td><a href="#uninstall"><tt>uninstall</tt></a></td><td></td>
429 <td>Remove built objects from installation directory.
433 <!-- ======================================================================= -->
434 <h3><a name="all">all (default)</a></h3>
436 <p>When you invoke <tt>make</tt> with no arguments, you are implicitly
437 instructing it to seek the "all" target (goal). This target is used for
438 building the software recursively and will do different things in different
439 directories. For example, in a <tt>lib</tt> directory, the "all" target will
440 compile source files and generate libraries. But, in a <tt>tools</tt>
441 directory, it will link libraries and generate executables.</p>
444 <!-- ======================================================================= -->
445 <h3><a name="all-local">all-local</a></h3>
447 <p>This target is the same as <a href="#all">all</a> but it operates only on
448 the current directory instead of recursively.</p>
451 <!-- ======================================================================= -->
452 <h3><a name="check">check</a></h3>
454 <p>This target can be invoked from anywhere within a project's directories
455 but always invokes the <a href="#check-local"><tt>check-local</tt></a> target
456 in the project's <tt>test</tt> directory, if it exists and has a
457 <tt>Makefile</tt>. A warning is produced otherwise. If
458 <a href="#TESTSUITE"><tt>TESTSUITE</tt></a> is defined on the <tt>make</tt>
459 command line, it will be passed down to the invocation of
460 <tt>make check-local</tt> in the <tt>test</tt> directory. The intended usage
461 for this is to assist in running specific suites of tests. If
462 <tt>TESTSUITE</tt> is not set, the implementation of <tt>check-local</tt>
463 should run all normal tests. It is up to the project to define what
464 different values for <tt>TESTSUTE</tt> will do. See the
465 <a href="TestingGuide.html">TestingGuide</a> for further details.</p>
468 <!-- ======================================================================= -->
469 <h3><a name="check-local">check-local</a></h3>
471 <p>This target should be implemented by the <tt>Makefile</tt> in the project's
472 <tt>test</tt> directory. It is invoked by the <tt>check</tt> target elsewhere.
473 Each project is free to define the actions of <tt>check-local</tt> as
474 appropriate for that project. The LLVM project itself uses dejagnu to run a
475 suite of feature and regresson tests. Other projects may choose to use
476 dejagnu or any other testing mechanism.</p>
479 <!-- ======================================================================= -->
480 <h3><a name="clean">clean</a></h3>
482 <p>This target cleans the build directory, recursively removing all things
483 that the Makefile builds. The cleaning rules have been made guarded so they
484 shouldn't go awry (via <tt>rm -f $(UNSET_VARIABLE)/*</tt> which will attempt
485 to erase the entire directory structure.</p>
488 <!-- ======================================================================= -->
489 <h3><a name="clean-local">clean-local</a></h3>
491 <p>This target does the same thing as <tt>clean</tt> but only for the current
492 (local) directory.</p>
495 <!-- ======================================================================= -->
496 <h3><a name="dist">dist</a></h3>
498 <p>This target builds a distribution tarball. It first builds the entire
499 project using the <tt>all</tt> target and then tars up the necessary files and
500 compresses it. The generated tarball is sufficient for a casual source
501 distribution, but probably not for a release (see <tt>dist-check</tt>).</p>
504 <!-- ======================================================================= -->
505 <h3><a name="dist-check">dist-check</a></h3>
507 <p>This target does the same thing as the <tt>dist</tt> target but also checks
508 the distribution tarball. The check is made by unpacking the tarball to a new
509 directory, configuring it, building it, installing it, and then verifying that
510 the installation results are correct (by comparing to the original build).
511 This target can take a long time to run but should be done before a release
512 goes out to make sure that the distributed tarball can actually be built into
513 a working release.</p>
516 <!-- ======================================================================= -->
517 <h3><a name="dist-clean">dist-clean</a></h3>
519 <p>This is a special form of the <tt>clean</tt> clean target. It performs a
520 normal <tt>clean</tt> but also removes things pertaining to building the
524 <!-- ======================================================================= -->
525 <h3><a name="install">install</a></h3>
527 <p>This target finalizes shared objects and executables and copies all
528 libraries, headers, executables and documentation to the directory given
529 with the <tt>--prefix</tt> option to <tt>configure</tt>. When completed,
530 the prefix directory will have everything needed to <b>use</b> LLVM. </p>
531 <p>The LLVM makefiles can generate complete <b>internal</b> documentation
532 for all the classes by using <tt>doxygen</tt>. By default, this feature is
533 <b>not</b> enabled because it takes a long time and generates a massive
534 amount of data (>100MB). If you want this feature, you must configure LLVM
535 with the --enable-doxygen switch and ensure that a modern version of doxygen
536 (1.3.7 or later) is available in your <tt>PATH</tt>. You can download
538 <a href="http://www.stack.nl/~dimitri/doxygen/download.html#latestsrc">
542 <!-- ======================================================================= -->
543 <h3><a name="preconditions">preconditions</a></h3>
545 <p>This utility target checks to see if the <tt>Makefile</tt> in the object
546 directory is older than the <tt>Makefile</tt> in the source directory and
547 copies it if so. It also reruns the <tt>configure</tt> script if that needs to
548 be done and rebuilds the <tt>Makefile.config</tt> file similarly. Users may
549 overload this target to ensure that sanity checks are run <em>before</em> any
550 building of targets as all the targets depend on <tt>preconditions</tt>.</p>
553 <!-- ======================================================================= -->
554 <h3><a name="printvars">printvars</a></h3>
556 <p>This utility target just causes the LLVM makefiles to print out some of
557 the makefile variables so that you can double check how things are set. </p>
560 <!-- ======================================================================= -->
561 <h3><a name="reconfigure">reconfigure</a></h3>
563 <p>This utility target will force a reconfigure of LLVM or your project. It
564 simply runs <tt>$(PROJ_OBJ_ROOT)/config.status --recheck</tt> to rerun the
565 configuration tests and rebuild the configured files. This isn't generally
566 useful as the makefiles will reconfigure themselves whenever its necessary.
570 <!-- ======================================================================= -->
571 <h3><a name="spotless">spotless</a></h3>
573 <p>This utility target, only available when <tt>$(PROJ_OBJ_ROOT)</tt> is not
574 the same as <tt>$(PROJ_SRC_ROOT)</tt>, will completely clean the
575 <tt>$(PROJ_OBJ_ROOT)</tt> directory by removing its content entirely and
576 reconfiguring the directory. This returns the <tt>$(PROJ_OBJ_ROOT)</tt>
577 directory to a completely fresh state. All content in the directory except
578 configured files and top-level makefiles will be lost.</p>
579 <div class="doc_warning"><p>Use with caution.</p></div>
582 <!-- ======================================================================= -->
583 <h3><a name="tags">tags</a></h3>
585 <p>This target will generate a <tt>TAGS</tt> file in the top-level source
586 directory. It is meant for use with emacs, XEmacs, or ViM. The TAGS file
587 provides an index of symbol definitions so that the editor can jump you to the
588 definition quickly. </p>
591 <!-- ======================================================================= -->
592 <h3><a name="uninstall">uninstall</a></h3>
594 <p>This target is the opposite of the <tt>install</tt> target. It removes the
595 header, library and executable files from the installation directories. Note
596 that the directories themselves are not removed because it is not guaranteed
597 that LLVM is the only thing installing there (e.g. --prefix=/usr).</p>
602 <!-- *********************************************************************** -->
603 <h2><a name="variables">Variables</a></h2>
604 <!-- *********************************************************************** -->
606 <p>Variables are used to tell the LLVM Makefile System what to do and to
607 obtain information from it. Variables are also used internally by the LLVM
608 Makefile System. Variable names that contain only the upper case alphabetic
609 letters and underscore are intended for use by the end user. All other
610 variables are internal to the LLVM Makefile System and should not be relied
611 upon nor modified. The sections below describe how to use the LLVM Makefile
614 <!-- ======================================================================= -->
615 <h3><a name="setvars">Control Variables</a></h3>
617 <p>Variables listed in the table below should be set <em>before</em> the
618 inclusion of <a href="#Makefile.common"><tt>$(LEVEL)/Makefile.common</tt></a>.
619 These variables provide input to the LLVM make system that tell it what to do
620 for the current directory.</p>
622 <dt><a name="BUILD_ARCHIVE"><tt>BUILD_ARCHIVE</tt></a></dt>
623 <dd>If set to any value, causes an archive (.a) library to be built.</dd>
624 <dt><a name="BUILT_SOURCES"><tt>BUILT_SOURCES</tt></a></dt>
625 <dd>Specifies a set of source files that are generated from other source
626 files. These sources will be built before any other target processing to
627 ensure they are present.</dd>
628 <dt><a name="BYTECODE_LIBRARY"><tt>BYTECODE_LIBRARY</tt></a></dt>
629 <dd>If set to any value, causes a bitcode library (.bc) to be built.</dd>
630 <dt><a name="CONFIG_FILES"><tt>CONFIG_FILES</tt></a></dt>
631 <dd>Specifies a set of configuration files to be installed.</dd>
632 <dt><a name="DEBUG_SYMBOLS"><tt>DEBUG_SYMBOLS</tt></a></dt>
633 <dd>If set to any value, causes the build to include debugging
634 symbols even in optimized objects, libraries and executables. This
635 alters the flags specified to the compilers and linkers. Debugging
636 isn't fun in an optimized build, but it is possible.</dd>
637 <dt><a name="DIRS"><tt>DIRS</tt></a></dt>
638 <dd>Specifies a set of directories, usually children of the current
639 directory, that should also be made using the same goal. These directories
640 will be built serially.</dd>
641 <dt><a name="DISABLE_AUTO_DEPENDENCIES"><tt>DISABLE_AUTO_DEPENDENCIES</tt></a></dt>
642 <dd>If set to any value, causes the makefiles to <b>not</b> automatically
643 generate dependencies when running the compiler. Use of this feature is
644 discouraged and it may be removed at a later date.</dd>
645 <dt><a name="ENABLE_OPTIMIZED"><tt>ENABLE_OPTIMIZED</tt></a></dt>
646 <dd>If set to 1, causes the build to generate optimized objects,
647 libraries and executables. This alters the flags specified to the compilers
648 and linkers. Generally debugging won't be a fun experience with an optimized
650 <dt><a name="ENABLE_PROFILING"><tt>ENABLE_PROFILING</tt></a></dt>
651 <dd>If set to 1, causes the build to generate both optimized and
652 profiled objects, libraries and executables. This alters the flags specified
653 to the compilers and linkers to ensure that profile data can be collected
654 from the tools built. Use the <tt>gprof</tt> tool to analyze the output from
655 the profiled tools (<tt>gmon.out</tt>).</dd>
656 <dt><a name="DISABLE_ASSERTIONS"><tt>DISABLE_ASSERTIONS</tt></a></dt>
657 <dd>If set to 1, causes the build to disable assertions, even if
658 building a debug or profile build. This will exclude all assertion check
659 code from the build. LLVM will execute faster, but with little help when
660 things go wrong.</dd>
661 <dt><a name="EXPERIMENTAL_DIRS"><tt>EXPERIMENTAL_DIRS</tt></a></dt>
662 <dd>Specify a set of directories that should be built, but if they fail, it
663 should not cause the build to fail. Note that this should only be used
664 temporarily while code is being written.</dd>
665 <dt><a name="EXPORTED_SYMBOL_FILE"><tt>EXPORTED_SYMBOL_FILE</tt></a></dt>
666 <dd>Specifies the name of a single file that contains a list of the
667 symbols to be exported by the linker. One symbol per line.</dd>
668 <dt><a name="EXPORTED_SYMBOL_LIST"><tt>EXPORTED_SYMBOL_LIST</tt></a></dt>
669 <dd>Specifies a set of symbols to be exported by the linker.</dd>
670 <dt><a name="EXTRA_DIST"><tt>EXTRA_DIST</tt></a></dt>
671 <dd>Specifies additional files that should be distributed with LLVM. All
672 source files, all built sources, all Makefiles, and most documentation files
673 will be automatically distributed. Use this variable to distribute any
674 files that are not automatically distributed.</dd>
675 <dt><a name="KEEP_SYMBOLS"><tt>KEEP_SYMBOLS</tt></a></dt>
676 <dd>If set to any value, specifies that when linking executables the
677 makefiles should retain debug symbols in the executable. Normally, symbols
678 are stripped from the executable.</dd>
679 <dt><a name="LEVEL"><tt>LEVEL</tt></a><small>(required)</small></dt>
680 <dd>Specify the level of nesting from the top level. This variable must be
681 set in each makefile as it is used to find the top level and thus the other
683 <dt><a name="LIBRARYNAME"><tt>LIBRARYNAME</tt></a></dt>
684 <dd>Specify the name of the library to be built. (Required For
686 <dt><a name="LINK_COMPONENTS"><tt>LINK_COMPONENTS</tt></a></dt>
687 <dd>When specified for building a tool, the value of this variable will be
688 passed to the <tt>llvm-config</tt> tool to generate a link line for the
689 tool. Unlike <tt>USEDLIBS</tt> and <tt>LLVMLIBS</tt>, not all libraries need
690 to be specified. The <tt>llvm-config</tt> tool will figure out the library
691 dependencies and add any libraries that are needed. The <tt>USEDLIBS</tt>
692 variable can still be used in conjunction with <tt>LINK_COMPONENTS</tt> so
693 that additional project-specific libraries can be linked with the LLVM
694 libraries specified by <tt>LINK_COMPONENTS</tt></dd>
695 <dt><a name="LINK_LIBS_IN_SHARED"><tt>LINK_LIBS_IN_SHARED</tt></a></dt>
696 <dd>By default, shared library linking will ignore any libraries specified
697 with the <a href="LLVMLIBS">LLVMLIBS</a> or <a href="USEDLIBS">USEDLIBS</a>.
698 This prevents shared libs from including things that will be in the LLVM
699 tool the shared library will be loaded into. However, sometimes it is useful
700 to link certain libraries into your shared library and this option enables
702 <dt><a name="LLVMLIBS"><tt>LLVMLIBS</tt></a></dt>
703 <dd>Specifies the set of libraries from the LLVM $(ObjDir) that will be
704 linked into the tool or library.</dd>
705 <dt><a name="LOADABLE_MODULE"><tt>LOADABLE_MODULE</tt></a></dt>
706 <dd>If set to any value, causes the shared library being built to also be
707 a loadable module. Loadable modules can be opened with the dlopen() function
708 and searched with dlsym (or the operating system's equivalent). Note that
709 setting this variable without also setting <tt>SHARED_LIBRARY</tt> will have
711 <dt><a name="MODULE_NAME"><tt>MODULE_NAME</tt></a></dt>
712 <dd>Specifies the name of a bitcode module to be created. A bitcode
713 module can be specified in conjunction with other kinds of library builds
714 or by itself. It constructs from the sources a single linked bitcode
716 <dt><a name="NO_INSTALL"><tt>NO_INSTALL</tt></a></dt>
717 <dd>Specifies that the build products of the directory should not be
718 installed but should be built even if the <tt>install</tt> target is given.
719 This is handy for directories that build libraries or tools that are only
720 used as part of the build process, such as code generators (e.g.
721 <tt>tblgen</tt>).</dd>
722 <dt><a name="OPTIONAL_DIRS"><tt>OPTIONAL_DIRS</tt></a></dt>
723 <dd>Specify a set of directories that may be built, if they exist, but its
724 not an error for them not to exist.</dd>
725 <dt><a name="PARALLEL_DIRS"><tt>PARALLEL_DIRS</tt></a></dt>
726 <dd>Specify a set of directories to build recursively and in parallel if
727 the -j option was used with <tt>make</tt>.</dd>
728 <dt><a name="SHARED_LIBRARY"><tt>SHARED_LIBRARY</tt></a></dt>
729 <dd>If set to any value, causes a shared library (.so) to be built in
730 addition to any other kinds of libraries. Note that this option will cause
731 all source files to be built twice: once with options for position
732 independent code and once without. Use it only where you really need a
734 <dt><a name="SOURCES"><tt>SOURCES</tt><small>(optional)</small></a></dt>
735 <dd>Specifies the list of source files in the current directory to be
736 built. Source files of any type may be specified (programs, documentation,
737 config files, etc.). If not specified, the makefile system will infer the
738 set of source files from the files present in the current directory.</dd>
739 <dt><a name="SUFFIXES"><tt>SUFFIXES</tt></a></dt>
740 <dd>Specifies a set of filename suffixes that occur in suffix match rules.
741 Only set this if your local <tt>Makefile</tt> specifies additional suffix
743 <dt><a name="TARGET"><tt>TARGET</tt></a></dt>
744 <dd>Specifies the name of the LLVM code generation target that the
745 current directory builds. Setting this variable enables additional rules to
746 build <tt>.inc</tt> files from <tt>.td</tt> files. </dd>
747 <dt><a name="TESTSUITE"><tt>TESTSUITE</tt></a></dt>
748 <dd>Specifies the directory of tests to run in <tt>llvm/test</tt>.</dd>
749 <dt><a name="TOOLNAME"><tt>TOOLNAME</tt></a></dt>
750 <dd>Specifies the name of the tool that the current directory should
752 <dt><a name="TOOL_VERBOSE"><tt>TOOL_VERBOSE</tt></a></dt>
753 <dd>Implies VERBOSE and also tells each tool invoked to be verbose. This is
754 handy when you're trying to see the sub-tools invoked by each tool invoked
755 by the makefile. For example, this will pass <tt>-v</tt> to the GCC
756 compilers which causes it to print out the command lines it uses to invoke
757 sub-tools (compiler, assembler, linker).</dd>
758 <dt><a name="USEDLIBS"><tt>USEDLIBS</tt></a></dt>
759 <dd>Specifies the list of project libraries that will be linked into the
760 tool or library.</dd>
761 <dt><a name="VERBOSE"><tt>VERBOSE</tt></a></dt>
762 <dd>Tells the Makefile system to produce detailed output of what it is doing
763 instead of just summary comments. This will generate a LOT of output.</dd>
767 <!-- ======================================================================= -->
768 <h3><a name="overvars">Override Variables</a></h3>
770 <p>Override variables can be used to override the default
771 values provided by the LLVM makefile system. These variables can be set in
774 <li>In the environment (e.g. setenv, export) -- not recommended.</li>
775 <li>On the <tt>make</tt> command line -- recommended.</li>
776 <li>On the <tt>configure</tt> command line</li>
777 <li>In the Makefile (only <em>after</em> the inclusion of <a
778 href="#Makefile.common"><tt>$(LEVEL)/Makefile.common</tt></a>).</li>
780 <p>The override variables are given below:</p>
782 <dt><a name="AR"><tt>AR</tt></a> <small>(defaulted)</small></dt>
783 <dd>Specifies the path to the <tt>ar</tt> tool.</dd>
784 <dt><a name="PROJ_OBJ_DIR"><tt>PROJ_OBJ_DIR</tt></a></dt>
785 <dd>The directory into which the products of build rules will be placed.
786 This might be the same as
787 <a href="#PROJ_SRC_DIR"><tt>PROJ_SRC_DIR</tt></a> but typically is
789 <dt><a name="PROJ_SRC_DIR"><tt>PROJ_SRC_DIR</tt></a></dt>
790 <dd>The directory which contains the source files to be built.</dd>
791 <dt><a name="BUILD_EXAMPLES"><tt>BUILD_EXAMPLES</tt></a></dt>
792 <dd>If set to 1, build examples in <tt>examples</tt> and (if building
793 Clang) <tt>tools/clang/examples</tt> directories.</dd>
794 <dt><a name="BZIP2"><tt>BZIP2</tt></a><small>(configured)</small></dt>
795 <dd>The path to the <tt>bzip2</tt> tool.</dd>
796 <dt><a name="CC"><tt>CC</tt></a><small>(configured)</small></dt>
797 <dd>The path to the 'C' compiler.</dd>
798 <dt><a name="CFLAGS"><tt>CFLAGS</tt></a></dt>
799 <dd>Additional flags to be passed to the 'C' compiler.</dd>
800 <dt><a name="CXX"><tt>CXX</tt></a></dt>
801 <dd>Specifies the path to the C++ compiler.</dd>
802 <dt><a name="CXXFLAGS"><tt>CXXFLAGS</tt></a></dt>
803 <dd>Additional flags to be passed to the C++ compiler.</dd>
804 <dt><a name="DATE"><tt>DATE<small>(configured)</small></tt></a></dt>
805 <dd>Specifies the path to the <tt>date</tt> program or any program that can
806 generate the current date and time on its standard output</dd>
807 <dt><a name="DOT"><tt>DOT</tt></a><small>(configured)</small></dt>
808 <dd>Specifies the path to the <tt>dot</tt> tool or <tt>false</tt> if there
810 <dt><a name="ECHO"><tt>ECHO</tt></a><small>(configured)</small></dt>
811 <dd>Specifies the path to the <tt>echo</tt> tool for printing output.</dd>
812 <dt><a name="EXEEXT"><tt>EXEEXT</tt></a><small>(configured)</small></dt>
813 <dd>Provides the extension to be used on executables built by the makefiles.
814 The value may be empty on platforms that do not use file extensions for
815 executables (e.g. Unix).</dd>
816 <dt><a name="INSTALL"><tt>INSTALL</tt></a><small>(configured)</small></dt>
817 <dd>Specifies the path to the <tt>install</tt> tool.</dd>
818 <dt><a name="LDFLAGS"><tt>LDFLAGS</tt></a><small>(configured)</small></dt>
819 <dd>Allows users to specify additional flags to pass to the linker.</dd>
820 <dt><a name="LIBS"><tt>LIBS</tt></a><small>(configured)</small></dt>
821 <dd>The list of libraries that should be linked with each tool.</dd>
822 <dt><a name="LIBTOOL"><tt>LIBTOOL</tt></a><small>(configured)</small></dt>
823 <dd>Specifies the path to the <tt>libtool</tt> tool. This tool is renamed
824 <tt>mklib</tt> by the <tt>configure</tt> script and always located in the
825 <dt><a name="LLVMAS"><tt>LLVMAS</tt></a><small>(defaulted)</small></dt>
826 <dd>Specifies the path to the <tt>llvm-as</tt> tool.</dd>
827 <dt><a name="LLVMCC"><tt>LLVMCC</tt></a></dt>
828 <dd>Specifies the path to the LLVM capable compiler.</dd>
829 <dt><a name="LLVMCXX"><tt>LLVMCXX</tt></a></dt>
830 <dd>Specifies the path to the LLVM C++ capable compiler.</dd>
831 <dt><a name="LLVMGCC"><tt>LLVMGCC</tt></a><small>(defaulted)</small></dt>
832 <dd>Specifies the path to the LLVM version of the GCC 'C' Compiler</dd>
833 <dt><a name="LLVMGXX"><tt>LLVMGXX</tt></a><small>(defaulted)</small></dt>
834 <dd>Specifies the path to the LLVM version of the GCC C++ Compiler</dd>
835 <dt><a name="LLVMLD"><tt>LLVMLD</tt></a><small>(defaulted)</small></dt>
836 <dd>Specifies the path to the LLVM bitcode linker tool</dd>
837 <dt><a name="LLVM_OBJ_ROOT"><tt>LLVM_OBJ_ROOT</tt></a><small>(configured)
839 <dd>Specifies the top directory into which the output of the build is
841 <dt><a name="LLVM_SRC_ROOT"><tt>LLVM_SRC_ROOT</tt></a><small>(configured)
843 <dd>Specifies the top directory in which the sources are found.</dd>
844 <dt><a name="LLVM_TARBALL_NAME"><tt>LLVM_TARBALL_NAME</tt></a>
845 <small>(configured)</small></dt>
846 <dd>Specifies the name of the distribution tarball to create. This is
847 configured from the name of the project and its version number.</dd>
848 <dt><a name="MKDIR"><tt>MKDIR</tt></a><small>(defaulted)</small></dt>
849 <dd>Specifies the path to the <tt>mkdir</tt> tool that creates
851 <dt><a name="ONLY_TOOLS"><tt>ONLY_TOOLS</tt></a></dt>
852 <dd>If set, specifies the list of tools to build.</dd>
853 <dt><a name="PLATFORMSTRIPOPTS"><tt>PLATFORMSTRIPOPTS</tt></a></dt>
854 <dd>The options to provide to the linker to specify that a stripped (no
855 symbols) executable should be built.</dd>
856 <dt><a name="RANLIB"><tt>RANLIB</tt></a><small>(defaulted)</small></dt>
857 <dd>Specifies the path to the <tt>ranlib</tt> tool.</dd>
858 <dt><a name="RM"><tt>RM</tt></a><small>(defaulted)</small></dt>
859 <dd>Specifies the path to the <tt>rm</tt> tool.</dd>
860 <dt><a name="SED"><tt>SED</tt></a><small>(defaulted)</small></dt>
861 <dd>Specifies the path to the <tt>sed</tt> tool.</dd>
862 <dt><a name="SHLIBEXT"><tt>SHLIBEXT</tt></a><small>(configured)</small></dt>
863 <dd>Provides the filename extension to use for shared libraries.</dd>
864 <dt><a name="TBLGEN"><tt>TBLGEN</tt></a><small>(defaulted)</small></dt>
865 <dd>Specifies the path to the <tt>tblgen</tt> tool.</dd>
866 <dt><a name="TAR"><tt>TAR</tt></a><small>(defaulted)</small></dt>
867 <dd>Specifies the path to the <tt>tar</tt> tool.</dd>
868 <dt><a name="ZIP"><tt>ZIP</tt></a><small>(defaulted)</small></dt>
869 <dd>Specifies the path to the <tt>zip</tt> tool.</dd>
873 <!-- ======================================================================= -->
874 <h3><a name="getvars">Readable Variables</a></h3>
876 <p>Variables listed in the table below can be used by the user's Makefile but
877 should not be changed. Changing the value will generally cause the build to go
878 wrong, so don't do it.</p>
880 <dt><a name="bindir"><tt>bindir</tt></a></dt>
881 <dd>The directory into which executables will ultimately be installed. This
882 value is derived from the <tt>--prefix</tt> option given to
883 <tt>configure</tt>.</dd>
884 <dt><a name="BuildMode"><tt>BuildMode</tt></a></dt>
885 <dd>The name of the type of build being performed: Debug, Release, or
887 <dt><a name="bitcode_libdir"><tt>bytecode_libdir</tt></a></dt>
888 <dd>The directory into which bitcode libraries will ultimately be
889 installed. This value is derived from the <tt>--prefix</tt> option given to
890 <tt>configure</tt>.</dd>
891 <dt><a name="ConfigureScriptFLAGS"><tt>ConfigureScriptFLAGS</tt></a></dt>
892 <dd>Additional flags given to the <tt>configure</tt> script when
894 <dt><a name="DistDir"><tt>DistDir</tt></a></dt>
895 <dd>The <em>current</em> directory for which a distribution copy is being
897 <dt><a name="Echo"><tt>Echo</tt></a></dt>
898 <dd>The LLVM Makefile System output command. This provides the
899 <tt>llvm[n]</tt> prefix and starts with @ so the command itself is not
900 printed by <tt>make</tt>.</dd>
901 <dt><a name="EchoCmd"><tt>EchoCmd</tt></a></dt>
902 <dd> Same as <a href="#Echo"><tt>Echo</tt></a> but without the leading @.
904 <dt><a name="includedir"><tt>includedir</tt></a></dt>
905 <dd>The directory into which include files will ultimately be installed.
906 This value is derived from the <tt>--prefix</tt> option given to
907 <tt>configure</tt>.</dd>
908 <dt><a name="libdir"><tt>libdir</tt></a></dt><dd></dd>
909 <dd>The directory into which native libraries will ultimately be installed.
910 This value is derived from the <tt>--prefix</tt> option given to
911 <tt>configure</tt>.</dd>
912 <dt><a name="LibDir"><tt>LibDir</tt></a></dt>
913 <dd>The configuration specific directory into which libraries are placed
914 before installation.</dd>
915 <dt><a name="MakefileConfig"><tt>MakefileConfig</tt></a></dt>
916 <dd>Full path of the <tt>Makefile.config</tt> file.</dd>
917 <dt><a name="MakefileConfigIn"><tt>MakefileConfigIn</tt></a></dt>
918 <dd>Full path of the <tt>Makefile.config.in</tt> file.</dd>
919 <dt><a name="ObjDir"><tt>ObjDir</tt></a></dt>
920 <dd>The configuration and directory specific directory where build objects
921 (compilation results) are placed.</dd>
922 <dt><a name="SubDirs"><tt>SubDirs</tt></a></dt>
923 <dd>The complete list of sub-directories of the current directory as
924 specified by other variables.</dd>
925 <dt><a name="Sources"><tt>Sources</tt></a></dt>
926 <dd>The complete list of source files.</dd>
927 <dt><a name="sysconfdir"><tt>sysconfdir</tt></a></dt>
928 <dd>The directory into which configuration files will ultimately be
929 installed. This value is derived from the <tt>--prefix</tt> option given to
930 <tt>configure</tt>.</dd>
931 <dt><a name="ToolDir"><tt>ToolDir</tt></a></dt>
932 <dd>The configuration specific directory into which executables are placed
933 before they are installed.</dd>
934 <dt><a name="TopDistDir"><tt>TopDistDir</tt></a></dt>
935 <dd>The top most directory into which the distribution files are copied.
937 <dt><a name="Verb"><tt>Verb</tt></a></dt>
938 <dd>Use this as the first thing on your build script lines to enable or
939 disable verbose mode. It expands to either an @ (quiet mode) or nothing
940 (verbose mode). </dd>
944 <!-- ======================================================================= -->
945 <h3><a name="intvars">Internal Variables</a></h3>
947 <p>Variables listed below are used by the LLVM Makefile System
948 and considered internal. You should not use these variables under any
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1034 <a href="mailto:rspencer@x10sys.com">Reid Spencer</a><br>
1035 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
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