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10 <div class="doc_title">LLVM Makefile Guide</div>
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="#Modules">Bytecode Modules</a></li>
36 <li><a href="#tools">Tools</a>
38 <li><a href="#JIT">JIT Tools</a></li>
43 <li><a href="#targets">Targets Supported</a>
45 <li><a href="#all">all</a></li>
46 <li><a href="#all-local">all-local</a></li>
47 <li><a href="#check">check</a></li>
48 <li><a href="#check-local">check-local</a></li>
49 <li><a href="#clean">clean</a></li>
50 <li><a href="#clean-local">clean-local</a></li>
51 <li><a href="#dist">dist</a></li>
52 <li><a href="#dist-check">dist-check</a></li>
53 <li><a href="#dist-clean">dist-clean</a></li>
54 <li><a href="#install">install</a></li>
55 <li><a href="#preconditions">preconditions</a></li>
56 <li><a href="#printvars">printvars</a></li>
57 <li><a href="#reconfigure">reconfigure</a></li>
58 <li><a href="#spotless">spotless</a></li>
59 <li><a href="#tags">tags</a></li>
60 <li><a href="#uninstall">uninstall</a></li>
63 <li><a href="#variables">Using Variables</a>
65 <li><a href="#setvars">Control Variables</a></li>
66 <li><a href="#overvars">Override Variables</a></li>
67 <li><a href="#getvars">Readable Variables</a></li>
68 <li><a href="#intvars">Internal Variables</a></li>
73 <div class="doc_author">
74 <p>Written by <a href="mailto:reid@x10sys.com">Reid Spencer</a></p>
77 <!-- *********************************************************************** -->
78 <div class="doc_section"><a name="introduction">Introduction </a></div>
79 <!-- *********************************************************************** -->
81 <div class="doc_text">
82 <p>This document provides <em>usage</em> information about the LLVM makefile
83 system. While loosely patterned after the BSD makefile system, LLVM has taken
84 a departure from BSD in order to implement additional features needed by LLVM.
85 Although makefile systems such as automake were attempted at one point, it
86 has become clear that the features needed by LLVM and the Makefile norm are
87 too great to use a more limited tool. Consequently, LLVM requires simply GNU
88 Make 3.79, a widely portable makefile processor. LLVM unabashedly makes heavy
89 use of the features of GNU Make so the dependency on GNU Make is firm. If
90 you're not familiar with <tt>make</tt>, it is recommended that you read the
91 <a href="http://www.gnu.org/software/make/manual/make.html">GNU Makefile Manual
93 <p>While this document is rightly part of the
94 <a href="ProgrammersManual.html">LLVM Programmer's Manual</a>, it is treated
95 separately here because of the volume of content and because it is often an
96 early source of bewilderment for new developers.</p>
99 <!-- *********************************************************************** -->
100 <div class="doc_section"><a name="general">General Concepts</a></div>
101 <!-- *********************************************************************** -->
103 <div class="doc_text">
104 <p>The LLVM Makefile System is the component of LLVM that is responsible for
105 building the software, testing it, generating distributions, checking those
106 distributions, installing and uninstalling, etc. It consists of a several
107 files throughout the source tree. These files and other general concepts are
108 described in this section.</p>
111 <!-- ======================================================================= -->
112 <div class="doc_subsection"><a name="projects">Projects</a></div>
113 <div class="doc_text">
114 <p>The LLVM Makefile System is quite generous. It not only builds its own
115 software, but it can build yours too. Built into the system is knowledge of
116 the <tt>llvm/projects</tt> directory. Any directory under <tt>projects</tt>
117 that has both a <tt>configure</tt> script and a <tt>Makefile</tt> is assumed
118 to be a project that uses the LLVM Makefile system. This allows your project
119 to get up and running quickly by utilizing the built-in features that are used
120 to compile LLVM. LLVM compiles itself using the same features of the makefile
121 system as used for projects.</p>
124 <!-- ======================================================================= -->
125 <div class="doc_subsection"><a name="varvalues">Variable Values</a></div>
126 <div class="doc_text">
127 <p>To use the makefile system, you simply create a file named
128 <tt>Makefile</tt> in your directory and declare values for certain variables.
129 The variables and values that you select determine what the makefile system
130 will do. These variables enable rules and processing in the makefile system
131 that automatically Do The Right Thing™.
134 <!-- ======================================================================= -->
135 <div class="doc_subsection"><a name="including">Including Makefiles</a></div>
136 <div class="doc_text">
137 <p>Setting variables alone is not enough. You must include into your Makefile
138 additional files that provide the rules of the LLVM Makefile system. The
139 various files involved are described in the sections that follow.</p>
142 <!-- ======================================================================= -->
143 <div class="doc_subsubsection"><a name="Makefile">Makefile</a></div>
144 <div class="doc_text">
145 <p>Each directory to participate in the build needs to have a file named
146 <tt>Makefile</tt>. This is the file first read by <tt>make</tt>. It has three
149 <li><a href="#setvars">Settable Variables</a> - Required that must be set
151 <li><a href="#Makefile.common">include <tt>$(LEVEL)/Makefile.common</tt></a>
152 - include the LLVM Makefile system.
153 <li><a href="#overvars">Override Variables</a> - Override variables set by
154 the LLVM Makefile system.
158 <!-- ======================================================================= -->
159 <div class="doc_subsubsection"><a name="Makefile.common">Makefile.common</a>
161 <div class="doc_text">
162 <p>Every project must have a <tt>Makefile.common</tt> file at its top source
163 directory. This file serves three purposes:</p>
165 <li>It includes the project's configuration makefile to obtain values
166 determined by the <tt>configure</tt> script. This is done by including the
167 <a href="#Makefile.config"><tt>$(LEVEL)/Makefile.config</tt></a> file.</li>
168 <li>It specifies any other (static) values that are needed throughout the
169 project. Only values that are used in all or a large proportion of the
170 project's directories should be placed here.</li>
171 <li>It includes the standard rules for the LLVM Makefile system,
172 <a href="#Makefile.rules"><tt>$(LLVM_SRC_ROOT)/Makefile.rules</tt></a>.
173 This file is the "guts" of the LLVM Makefile system.</li>
177 <!-- ======================================================================= -->
178 <div class="doc_subsubsection"><a name="Makefile.config">Makefile.config</a>
180 <div class="doc_text">
181 <p>Every project must have a <tt>Makefile.config</tt> at the top of its
182 <em>build</em> directory. This file is <b>generated</b> by the
183 <tt>configure</tt> script from the pattern provided by the
184 <tt>Makefile.config.in</tt> file located at the top of the project's
185 <em>source</em> directory. The contents of this file depend largely on what
186 configuration items the project uses, however most projects can get what they
187 need by just relying on LLVM's configuration found in
188 <tt>$(LLVM_OBJ_ROOT)/Makefile.config</tt>.
191 <!-- ======================================================================= -->
192 <div class="doc_subsubsection"><a name="Makefile.rules">Makefile.rules</a></div>
193 <div class="doc_text">
194 <p>This file, located at <tt>$(LLVM_SRC_ROOT)/Makefile.rules</tt> is the heart
195 of the LLVM Makefile System. It provides all the logic, dependencies, and
196 rules for building the targets supported by the system. What it does largely
197 depends on the values of <tt>make</tt> <a href="#variables">variables</a> that
198 have been set <em>before</em> <tt>Makefile.rules</tt> is included.
201 <!-- ======================================================================= -->
202 <div class="doc_subsection"><a name="Comments">Comments</a></div>
203 <div class="doc_text">
204 <p>User Makefiles need not have comments in them unless the construction is
205 unusual or it does not strictly follow the rules and patterns of the LLVM
206 makefile system. Makefile comments are invoked with the pound (#) character.
207 The # character and any text following it, to the end of the line, are ignored
208 by <tt>make</tt>.</p>
211 <!-- *********************************************************************** -->
212 <div class="doc_section"><a name="tutorial">Tutorial</a></div>
213 <!-- *********************************************************************** -->
214 <div class="doc_text">
215 <p>This section provides some examples of the different kinds of modules you
216 can build with the LLVM makefile system. In general, each directory you
217 provide will build a single object although that object may be composed of
218 additionally compiled components.</p>
221 <!-- ======================================================================= -->
222 <div class="doc_subsection"><a name="libraries">Libraries</a></div>
223 <div class="doc_text">
224 <p>Only a few variable definitions are needed to build a regular library.
225 Normally, the makefile system will build all the software into a single
226 <tt>libname.o</tt> (pre-linked) object. This means the library is not
227 searchable and that the distinction between compilation units has been
228 dissolved. Optionally, you can ask for a shared library (.so), archive library
229 (.a) or to not have the default (relinked) library built. For example:</p>
234 DONT_BUILT_RELINKED = 1
236 <p>says to build a library named "mylib" with both a shared library
237 (<tt>mylib.so</tt>) and an archive library (<tt>mylib.a</tt>) version but
238 not to build the relinked object (<tt>mylib.o</tt>). The contents of all the
239 libraries produced will be the same, they are just constructed differently.
240 Note that you normally do not need to specify the sources involved. The LLVM
241 Makefile system will infer the source files from the contents of the source
243 <p>The <tt>LOADABLE_MODULE=1</tt> directive can be used in conjunction with
244 <tt>SHARED_LIBRARY=1</tt> to indicate that the resulting shared library should
245 be openable with the <tt>dlopen</tt> function and searchable with the
246 <tt>dlsym</tt> function (or your operating system's equivalents). While this
247 isn't strictly necessary on Linux and a few other platforms, it is required
248 on systems like HP-UX and Darwin. You should use <tt>LOADABLE_MODULE</tt> for
249 any shared library that you intend to be loaded into an tool via the
250 <tt>-load</tt> option. See the
251 <a href="WritingAnLLVMPass.html#makefile">WritingAnLLVMPass.html</a> document
252 for an example of why you might want to do this.
255 <!-- ======================================================================= -->
256 <div class="doc_subsubsection"><a name="Modules">Bytecode Modules</a></div>
257 <div class="doc_text">
258 <p>In some situations, it is desireable to build a single bytecode module from
259 a variety of sources, instead of an archive, shared library, or bytecode
260 library. Bytecode modules can be specified in addition to any of the other
261 types of libraries by defining the <a href="#MODULE_NAME">MODULE_NAME</a>
262 variable. For example:</p>
268 <p>will build a module named <tt>mymod.bc</tt> from the sources in the
269 directory. This module will be an aggregation of all the bytecode modules
270 derived from the sources. The example will also build a bytecode archive
271 containing a bytecode module for each compiled source file. The difference is
272 subtle, but important depending on how the module or library is to be linked.
276 <!-- ======================================================================= -->
277 <div class="doc_subsection"><a name="tools">Tools</a></div>
278 <div class="doc_text">
279 <p>For building executable programs (tools), you must provide the name of the
280 tool and the names of the libraries you wish to link with the tool. For
285 LLVMLIBS = LLVMSupport.a LLVMSystem.a
287 <p>says that we are to build a tool name <tt>mytool</tt> and that it requires
288 three libraries: <tt>mylib</tt>, <tt>LLVMSupport.a</tt> and
289 <tt>LLVMSystem.a</tt>.</p>
290 <p>Note that two different variables are use to indicate which libraries are
291 linked: <tt>USEDLIBS</tt> and <tt>LLVMLIBS</tt>. This distinction is necessary
292 to support projects. <tt>LLVMLIBS</tt> refers to the LLVM libraries found in
293 the LLVM object directory. <tt>USEDLIBS</tt> refers to the libraries built by
294 your project. In the case of building LLVM tools, <tt>USEDLIBS</tt> and
295 <tt>LLVMLIBS</tt> can be used interchangeably since the "project" is LLVM
296 itself and <tt>USEDLIBS</tt> refers to the same place as <tt>LLVMLIBS</tt>.
298 <p>Also note that there are two different ways of specifying a library: with a
299 <tt>.a</tt> suffix and without. Without the suffix, the entry refers to the
300 re-linked (.o) file which will include <em>all</em> symbols of the library.
301 This is useful, for example, to include all passes from a library of passes.
302 If the <tt>.a</tt> suffix is used then the library is linked as a searchable
303 library (with the <tt>-l</tt> option). In this case, only the symbols that are
304 unresolved <em>at that point</em> will be resolved from the library, if they
305 exist. Other (unreferenced) symbols will not be included when the <tt>.a</tt>
306 syntax is used. Note that in order to use the <tt>.a</tt> suffix, the library
307 in question must have been built with the <tt>ARCHIVE_LIBRARY</tt> option set.
311 <!-- ======================================================================= -->
312 <div class="doc_subsubsection"><a name="JIT">JIT Tools</a></div>
313 <div class="doc_text">
314 <p>Many tools will want to use the JIT features of LLVM. However, getting the
315 right set of libraries to link with is tedious, platform specific, and error
316 prone. Additionally, the JIT has special linker switch options that it needs.
317 Consequently, to make it easier to build tools that use the JIT, you can
318 use a special value for the <tt>LLVMLIBS</tt> variable:</p>
320 TOOLNAME = my_jit_tool
324 <p>Using a value of <tt>JIT</tt> for <tt>LLVMLIBS</tt> tells the makefile
325 system to construct a special value for LLVMLIBS that gives the program all
326 the LLVM libraries needed to run the JIT. Any additional libraries needed can
327 still be specified with <tt>USEDLIBS</tt>. To get a full understanding of how
328 this changes the linker command, it is recommended that you:</p>
330 cd examples/Fibonacci
333 <p>By default, using <tt>LLVMLIBS=JIT</tt> will link in enough to support JIT
334 code generation for the architecture on which the tool is linked. If you need
335 additional target architectures linked in, you may specify them on the command
336 line or in your <tt>Makefile</tt>. For example:</p>
342 <p>will cause the tool to be able to generate code for all three platforms.
346 <!-- *********************************************************************** -->
347 <div class="doc_section"><a name="targets">Targets Supported</a></div>
348 <!-- *********************************************************************** -->
350 <div class="doc_text">
351 <p>This section describes each of the targets that can be built using the LLVM
352 Makefile system. Any target can be invoked from any directory but not all are
353 applicable to a given directory (e.g. "check", "dist" and "install" will
354 always operate as if invoked from the top level directory).</p>
356 <table style="text-align:left">
358 <th>Target Name</th><th>Implied Targets</th><th>Target Description</th>
360 <tr><td><a href="#all"><tt>all</tt></a></td><td></td>
361 <td>Compile the software recursively. Default target.
363 <tr><td><a href="#all-local"><tt>all-local</tt></a></td><td></td>
364 <td>Compile the software in the local directory only.
366 <tr><td><a href="#check"><tt>check</tt></a></td><td></td>
367 <td>Change to the <tt>test</tt> directory in a project and run the
370 <tr><td><a href="#check-local"><tt>check-local</tt></a></td><td></td>
371 <td>Run a local test suite. Generally this is only defined in the
372 <tt>Makefile</tt> of the project's <tt>test</tt> directory.
374 <tr><td><a href="#clean"><tt>clean</tt></a></td><td></td>
375 <td>Remove built objects recursively.
377 <tr><td><a href="#clean-local"><tt>clean-local</tt></a></td><td></td>
378 <td>Remove built objects from the local directory only.
380 <tr><td><a href="#dist"><tt>dist</tt></a></td><td>all</td>
381 <td>Prepare a source distribution tarball.
383 <tr><td><a href="#dist-check"><tt>dist-check</tt></a></td><td>all check</td>
384 <td>Prepare a source distribution tarball and check that it builds.
386 <tr><td><a href="#dist-clean"><tt>dist-clean</tt></a></td><td>clean</td>
387 <td>Clean source distribution tarball temporary files.
389 <tr><td><a href="#install"><tt>install</tt></a></td><td>all</td>
390 <td>Copy built objects to installation directory.
392 <tr><td><a href="#preconditions"><tt>preconditions</tt></a></td><td>all</td>
393 <td>Check to make sure configuration and makefiles are up to date.
395 <tr><td><a href="#printvars"><tt>printvars</tt></a></td><td>all</td>
396 <td>Prints variables defined by the makefile system (for debugging).
398 <tr><td><a href="#tags"><tt>tags</tt></a></td><td></td>
399 <td>Make C and C++ tags files for emacs and vi.
401 <tr><td><a href="#uninstall"><tt>uninstall</tt></a></td><td></td>
402 <td>Remove built objects from installation directory.
407 <!-- ======================================================================= -->
408 <div class="doc_subsection"><a name="all">all (default)</a></div>
409 <div class="doc_text">
410 <p>When you invoke <tt>make</tt> with no arguments, you are implicitly
411 instructing it to seek the "all" target (goal). This target is used for
412 building the software recursively and will do different things in different
413 directories. For example, in a <tt>lib</tt> directory, the "all" target will
414 compile source files and generate libraries. But, in a <tt>tools</tt>
415 directory, it will link libraries and generate executables.</p>
418 <!-- ======================================================================= -->
419 <div class="doc_subsection"><a name="all-local">all-local</a></div>
420 <div class="doc_text">
421 <p>This target is the same as <a href="#all">all</a> but it operates only on
422 the current directory instead of recursively.</p>
425 <!-- ======================================================================= -->
426 <div class="doc_subsection"><a name="check">check</a></div>
427 <div class="doc_text">
428 <p>This target can be invoked from anywhere within a project's directories
429 but always invokes the <a href="#check-local"><tt>check-local</tt></a> target
430 in the project's <tt>test</tt> directory, if it exists and has a
431 <tt>Makefile</tt>. A warning is produced otherwise. If
432 <a href="#TESTSUITE"><tt>TESTSUITE</tt></a> is defined on the <tt>make</tt>
433 command line, it will be passed down to the invocation of
434 <tt>make check-local</tt> in the <tt>test</tt> directory. The intended usage
435 for this is to assist in running specific suites of tests. If
436 <tt>TESTSUITE</tt> is not set, the implementation of <tt>check-local</tt>
437 should run all normal tests. It is up to the project to define what
438 different values for <tt>TESTSUTE</tt> will do. See the
439 <a href="TestingGuide.html">TestingGuide</a> for further details.</p>
442 <!-- ======================================================================= -->
443 <div class="doc_subsection"><a name="check-local">check-local</a></div>
444 <div class="doc_text">
445 <p>This target should be implemented by the <tt>Makefile</tt> in the project's
446 <tt>test</tt> directory. It is invoked by the <tt>check</tt> target elsewhere.
447 Each project is free to define the actions of <tt>check-local</tt> as
448 appropriate for that project. The LLVM project itself uses dejagnu to run a
449 suite of feature and regresson tests. Other projects may choose to use
450 dejagnu or any other testing mechanism.</p>
453 <!-- ======================================================================= -->
454 <div class="doc_subsection"><a name="clean">clean</a></div>
455 <div class="doc_text">
456 <p>This target cleans the build directory, recursively removing all things
457 that the Makefile builds. The cleaning rules have been made guarded so they
458 shouldn't go awry (via <tt>rm -f $(UNSET_VARIABLE)/*</tt> which will attempt
459 to erase the entire directory structure.</p>
462 <!-- ======================================================================= -->
463 <div class="doc_subsection"><a name="clean-local">clean-local</a></div>
464 <div class="doc_text">
465 <p>This target does the same thing as <tt>clean</tt> but only for the current
466 (local) directory.</p>
469 <!-- ======================================================================= -->
470 <div class="doc_subsection"><a name="dist">dist</a></div>
471 <div class="doc_text">
472 <p>This target builds a distribution tarball. It first builds the entire
473 project using the <tt>all</tt> target and then tars up the necessary files and
474 compresses it. The generated tarball is sufficient for a casual source
475 distribution, but probably not for a release (see <tt>dist-check</tt>).</p>
478 <!-- ======================================================================= -->
479 <div class="doc_subsection"><a name="dist-check">dist-check</a></div>
480 <div class="doc_text">
481 <p>This target does the same thing as the <tt>dist</tt> target but also checks
482 the distribution tarball. The check is made by unpacking the tarball to a new
483 directory, configuring it, building it, installing it, and then verifying that
484 the installation results are correct (by comparing to the original build).
485 This target can take a long time to run but should be done before a release
486 goes out to make sure that the distributed tarball can actually be built into
487 a working release.</p>
490 <!-- ======================================================================= -->
491 <div class="doc_subsection"><a name="dist-clean">dist-clean</a></div>
492 <div class="doc_text">
493 <p>This is a special form of the <tt>clean</tt> clean target. It performs a
494 normal <tt>clean</tt> but also removes things pertaining to building the
498 <!-- ======================================================================= -->
499 <div class="doc_subsection"><a name="install">install</a></div>
500 <div class="doc_text">
501 <p>This target finalizes shared objects and executables and copies all
502 libraries, headers, executables and documentation to the directory given
503 with the <tt>--prefix</tt> option to <tt>configure</tt>. When completed,
504 the prefix directory will have everything needed to <b>use</b> LLVM. </p>
505 <p>The LLVM makefiles can generate complete <b>internal</b> documentation
506 for all the classes by using <tt>doxygen</tt>. By default, this feature is
507 <b>not</b> enabled because it takes a long time and generates a massive
508 amount of data (>100MB). If you want this feature, you must configure LLVM
509 with the --enable-doxygen switch and ensure that a modern version of doxygen
510 (1.3.7 or later) is available in your <tt>PATH</tt>. You can download
512 <a href="http://www.stack.nl/~dimitri/doxygen/download.html#latestsrc">
516 <!-- ======================================================================= -->
517 <div class="doc_subsection"><a name="preconditions">preconditions</a></div>
518 <div class="doc_text">
519 <p>This utility target checks to see if the <tt>Makefile</tt> in the object
520 directory is older than the <tt>Makefile</tt> in the source directory and
521 copies it if so. It also reruns the <tt>configure</tt> script if that needs to
522 be done and rebuilds the <tt>Makefile.config</tt> file similarly. Users may
523 overload this target to ensure that sanity checks are run <em>before</em> any
524 building of targets as all the targets depend on <tt>preconditions</tt>.</p>
527 <!-- ======================================================================= -->
528 <div class="doc_subsection"><a name="printvars">printvars</a></div>
529 <div class="doc_text">
530 <p>This utility target just causes the LLVM makefiles to print out some of
531 the makefile variables so that you can double check how things are set. </p>
534 <!-- ======================================================================= -->
535 <div class="doc_subsection"><a name="reconfigure">reconfigure</a></div>
536 <div class="doc_text">
537 <p>This utility target will force a reconfigure of LLVM or your project. It
538 simply runs <tt>$(BUILD_OBJ_ROOT)/config.status --recheck</tt> to rerun the
539 configuration tests and rebuild the configured files. This isn't generally
540 useful as the makefiles will reconfigure themselves whenever its necessary.
544 <!-- ======================================================================= -->
545 <div class="doc_subsection"><a name="spotless">spotless</a></div>
546 <div class="doc_text">
547 <p>This utility target, only available when <tt>$(BUILD_OBJ_ROOT)</tt> is not
548 the same as <tt>$(BUILD_SRC_ROOT)</tt>, will completely clean the
549 <tt>$(BUILD_OBJ_ROOT)</tt> directoy by removing its content entirely and
550 reconfiguring the directory. This returns the <tt>$(BUILD_OBJ_ROOT)</tt>
551 directory to a completely fresh state. All content in the directory except
552 configured files and top-level makefiles will be lost.</p>
553 <div class="doc_warning"><p>Use with caution.</p></div>
556 <!-- ======================================================================= -->
557 <div class="doc_subsection"><a name="tags">tags</a></div>
558 <div class="doc_text">
559 <p>This target will generate a <tt>TAGS</tt> file in the top-level source
560 directory. It is meant for use with emacs, XEmacs, or ViM. The TAGS file
561 provides an index of symbol definitions so that the editor can jump you to the
562 definition quickly. </p>
565 <!-- ======================================================================= -->
566 <div class="doc_subsection"><a name="uninstall">uninstall</a></div>
567 <div class="doc_text">
568 <p>This target is the opposite of the <tt>install</tt> target. It removes the
569 header, library and executable files from the installation directories. Note
570 that the directories themselves are not removed because it is not guaranteed
571 that LLVM is the only thing installing there (e.g. --prefix=/usr).</p>
574 <!-- *********************************************************************** -->
575 <div class="doc_section"><a name="variables">Variables</a></div>
576 <!-- *********************************************************************** -->
577 <div class="doc_text">
578 <p>Variables are used to tell the LLVM Makefile System what to do and to
579 obtain information from it. Variables are also used internally by the LLVM
580 Makefile System. Variable names that contain only the upper case alphabetic
581 letters and underscore are intended for use by the end user. All other
582 variables are internal to the LLVM Makefile System and should not be relied
583 upon nor modified. The sections below describe how to use the LLVM Makefile
587 <!-- ======================================================================= -->
588 <div class="doc_subsection"><a name="setvars">Control Variables</a></div>
589 <div class="doc_text">
590 <p>Variables listed in the table below should be set <em>before</em> the
591 inclusion of <a href="#Makefile.common"><tt>$(LEVEL)/Makefile.common</tt></a>.
592 These variables provide input to the LLVM make system that tell it what to do
593 for the current directory.</p>
595 <dt><a name="BUILD_ARCHIVE"><tt>BUILD_ARCHIVE</tt></a></dt>
596 <dd>If set to any value, causes an archive (.a) library to be built.</dd>
597 <dt><a name="BUILT_SOURCES"><tt>BUILT_SOURCES</tt></a></dt>
598 <dd>Specifies a set of source files that are generated from other source
599 files. These sources will be built before any other target processing to
600 ensure they are present.</dd>
601 <dt><a name="BYTECODE_LIBRARY"><tt>BYTECODE_LIBRARY</tt></a></dt>
602 <dd>If set to any value, causes a bytecode library (.bc) to be built.</dd>
603 <dt><a name="CONFIG_FILES"><tt>CONFIG_FILES</tt></a></dt>
604 <dd>Specifies a set of configuration files to be installed.</dd>
605 <dt><a name="DIRS"><tt>DIRS</tt></a></dt>
606 <dd>Specifies a set of directories, usually children of the current
607 directory, that should also be made using the same goal. These directories
608 will be built serially.</dd>
609 <dt><a name="DISABLE_AUTO_DEPENDENCIES"><tt>DISABLE_AUTO_DEPENDENCIES</tt></a></dt>
610 <dd>If set to any value, causes the makefiles to <b>not</b> automatically
611 generate dependencies when running the compiler. Use of this feature is
612 discouraged and it may be removed at a later date.</dd>
613 <dt><a name="DONT_BUILD_RELINKED"><tt>DONT_BUILD_RELINKED</tt></a></dt>
614 <dd>If set to any value, causes a relinked library (.o) not to be built. By
615 default, libraries are built as re-linked since most LLVM libraries are
616 needed in their entirety and re-linked libraries will be linked more quickly
617 than equivalent archive libraries.</dd>
618 <dt><a name="ENABLE_OPTIMIZED"><tt>ENABLE_OPTIMIZED</tt></a></dt>
619 <dd>If set to any value, causes the build to generate optimized objects,
620 libraries and executables. This alters the flags specified to the compilers
621 and linkers. Generally debugging won't be a fun experience with an optimized
623 <dt><a name="ENABLE_PROFILING"><tt>ENABLE_PROFILING</tt></a></dt>
624 <dd>If set to any value, causes the build to generate both optimized and
625 profiled objects, libraries and executables. This alters the flags specified
626 to the compilers and linkers to ensure that profile data can be collected
627 from the tools built. Use the <tt>gprof</tt> tool to analyze the output from
628 the profiled tools (<tt>gmon.out</tt>).</dd>
629 <dt><a name="EXPERIMENTAL_DIRS"><tt>EXPERIMENTAL_DIRS</tt></a></dt>
630 <dd>Specify a set of directories that should be built, but if they fail, it
631 should not cause the build to fail. Note that this should only be used
632 temporarily while code is being written.</dd>
633 <dt><a name="EXPORTED_SYMBOL_FILE"><tt>EXPORTED_SYMBOL_FILE</tt></a></dt>
634 <dd>Specifies the name of a single file that contains a list of the
635 symbols to be exported by the linker. One symbol per line.</dd>
636 <dt><a name="EXPORTED_SYMBOL_LIST"><tt>EXPORTED_SYMBOL_LIST</tt></a></dt>
637 <dd>Specifies a set of symbols to be exported by the linker.</dd>
638 <dt><a name="EXTRA_DIST"><tt>EXTRA_DIST</tt></a></dt>
639 <dd>Specifies additional files that should be distributed with LLVM. All
640 source files, all built sources, all Makefiles, and most documentation files
641 will be automatically distributed. Use this variable to distribute any
642 files that are not automatically distributed.</dd>
643 <dt><a name="FAKE_SOURCES"><tt>FAKE_SOURCES</tt><small>(optional)</small>
645 <dd>This variable is like <a href="#SOURCES"><tt>SOURCES</tt></a> except that
646 the source files don't need to exist. The makefiles only use
647 <tt>FAKE_SOURCES</tt> to create the names of derived objects that should be
648 included in the directory's result. It is assumed that the project's
649 <tt>Makefile</tt> will define how to build the derived objects
651 <dt><a name="KEEP_SYMBOLS"><tt>KEEP_SYMBOLS</tt></a></dt>
652 <dd>If set to any value, specifies that when linking executables the
653 makefiles should retain debug symbols in the executable. Normally, symbols
654 are stripped from the executable.</dd>
655 <dt><a name="LEVEL"><tt>LEVEL</tt></a><small>(required)</small></dt>
656 <dd>Specify the level of nesting from the top level. This variable must be
657 set in each makefile as it is used to find the top level and thus the other
659 <dt><a name="LIBRARYNAME"><tt>LIBRARYNAME</tt></a></dt>
660 <dd>Specify the name of the library to be built. (Required For
662 <dt><a name="LLVMLIBS"><tt>LLVMLIBS</tt></a></dt>
663 <dd>Specifies the set of libraries from the LLVM $(ObjDir) that will be
664 linked into the tool or library.</dd>
665 <dt><a name="LOADABLE_MODULE"><tt>LOADABLE_MODULE</tt></a></dt>
666 <dd>If set to any value, causes the shared library being built to also be
667 a loadable module. Loadable modules can be opened with the dlopen() function
668 and searched with dlsym (or the operating system's equivalent). Note that
669 setting this variable without also setting <tt>SHARED_LIBRARY</tt> will have
671 <dt><a name="MODULE_NAME"><tt>MODULE_NAME</tt></a></dt>
672 <dd>Specifies the name of a bytecode module to be created. A bytecode
673 module can be specified in conjunction with other kinds of library builds
674 or by itself. It constructs from the sources a single linked bytecode
676 <dt><a name="OPTIONAL_DIRS"><tt>OPTIONAL_DIRS</tt></a></dt>
677 <dd>Specify a set of directories that may be built, if they exist, but its
678 not an error for them not to exist.</dd>
679 <dt><a name="PARALLEL_DIRS"><tt>PARALLEL_DIRS</tt></a></dt>
680 <dd>Specify a set of directories to build recursively and in parallel if
681 the -j option was used with <tt>make</tt>.</dd>
682 <dt><a name="SHARED_LIBRARY"><tt>SHARED_LIBRARY</tt></a></dt>
683 <dd>If set to any value, causes a shared library (.so) to be built in
684 addition to any other kinds of libraries. Note that this option will cause
685 all source files to be built twice: once with options for position
686 independent code and once without. Use it only where you really need a
688 <dt><a name="SOURCES"><tt>SOURCES</tt><small>(optional)</small></a></dt>
689 <dd>Specifies the list of source files in the current directory to be
690 built. Source files of any type may be specified (programs, documentation,
691 config files, etc.). If not specified, the makefile system will infer the
692 set of source files from the files present in the current directory.</dd>
693 <dt><a name="SUFFIXES"><tt>SUFFIXES</tt></a></dt>
694 <dd>Specifies a set of filename suffixes that occur in suffix match rules.
695 Only set this if your local <tt>Makefile</tt> specifies additional suffix
697 <dt><a name="TARGET"><tt>TARGET</tt></a></dt>
698 <dd>Specifies the name of the LLVM code generation target that the
699 current directory builds. Setting this variable enables additional rules to
700 build <tt>.inc</tt> files from <tt>.td</tt> files. </dd>
701 <dt><a name="TESTSUITE"><tt>TESTSUITE</tt></a></dt>
702 <dd>Specifies the directory of tests to run in <tt>llvm/test</tt>.</dd>
703 <dt><a name="TOOLNAME"><tt>TOOLNAME</tt></a></dt>
704 <dd>Specifies the name of the tool that the current directory should
706 <dt><a name="TOOL_VERBOSE"><tt>TOOL_VERBOSE</tt></a></dt>
707 <dd>Implies VERBOSE and also tells each tool invoked to be verbose. This is
708 handy when you're trying to see the sub-tools invoked by each tool invoked
709 by the makefile. For example, this will pass <tt>-v</tt> to the GCC
710 compilers which causes it to print out the command lines it uses to invoke
711 sub-tools (compiler, assembler, linker).</dd>
712 <dt><a name="USEDLIBS"><tt>USEDLIBS</tt></a></dt>
713 <dd>Specifies the list of project libraries that will be linked into the
714 tool or library.</dd>
715 <dt><a name="VERBOSE"><tt>VERBOSE</tt></a></dt>
716 <dd>Tells the Makefile system to produce detailed output of what it is doing
717 instead of just summary comments. This will generate a LOT of output.</dd>
721 <!-- ======================================================================= -->
722 <div class="doc_subsection"><a name="overvars">Override Variables</a></div>
723 <div class="doc_text">
724 <p>Override variables can be used to override the default
725 values provided by the LLVM makefile system. These variables can be set in
728 <li>In the environment (e.g. setenv, export) -- not recommended.</li>
729 <li>On the <tt>make</tt> command line -- recommended.</li>
730 <li>On the <tt>configure</tt> command line</li>
731 <li>In the Makefile (only <em>after</em> the inclusion of <a
732 href="#Makefile.common"><tt>$(LEVEL)/Makefile.common</tt></a>).</li>
734 <p>The override variables are given below:</p>
736 <dt><a name="AR"><tt>AR</tt></a> <small>(defaulted)</small></dt>
737 <dd>Specifies the path to the <tt>ar</tt> tool.</dd>
738 <dt><a name="BISON"><tt>BISON</tt></a><small>(configured)</small></dt>
739 <dd>Specifies the path to the <tt>bison</tt> tool.</dd>
740 <dt><a name="BUILD_OBJ_DIR"><tt>BUILD_OBJ_DIR</tt></a></dt>
741 <dd>The directory into which the products of build rules will be placed.
742 This might be the same as
743 <a href="#BUILD_SRC_DIR"><tt>BUILD_SRC_DIR</tt></a> but typically is
745 <dt><a name="BUILD_SRC_DIR"><tt>BUILD_SRC_DIR</tt></a></dt>
746 <dd>The directory which contains the source files to be built.</dd>
747 <dt><a name="BURG"><tt>BURG</tt></a></dt>
748 <dd>Specifies the path to the <tt>burg</tt> tool.</dd>
749 <dt><a name="BZIP2"><tt>BZIP2</tt></a><small>(configured)</small></dt>
750 <dd>The path to the <tt>bzip2</tt> tool.</dd>
751 <dt><a name="CC"><tt>CC</tt></a><small>(configured)</small></dt>
752 <dd>The path to the 'C' compiler.</dd>
753 <dt><a name="CFLAGS"><tt>CFLAGS</tt></a></dt>
754 <dd>Additional flags to be passed to the 'C' compiler.</dd>
755 <dt><a name="CXX"><tt>CXX</tt></a></dt>
756 <dd>Specifies the path to the C++ compiler.</dd>
757 <dt><a name="CXXFLAGS"><tt>CXXFLAGS</tt></a></dt>
758 <dd>Additional flags to be passed to the C++ compiler.</dd>
759 <dt><a name="DATE"><tt>DATE<small>(configured)</small></tt></a></dt>
760 <dd>Specifies the path to the <tt>date</tt> program or any program that can
761 generate the current date and time on its standard output</dd>
762 <dt><a name="DOT"><tt>DOT</tt></a><small>(configured)</small></dt>
763 <dd>Specifies the path to the <tt>dot</tt> tool or <tt>false</tt> if there
765 <dt><a name="ECHO"><tt>ECHO</tt></a><small>(configured)</small></dt>
766 <dd>Specifies the path to the <tt>echo</tt> tool for printing output.</dd>
767 <dt><a name="ETAGS"><tt>ETAGS</tt></a><small>(configured)</small></dt>
768 <dd>Specifies the path to the <tt>etags</tt> tool.</dd>
769 <dt><a name="ETAGSFLAGS"><tt>ETAGSFLAGS</tt></a><small>(configured)</small></dt>
770 <dd>Provides flags to be passed to the <tt>etags</tt> tool.</dd>
771 <dt><a name="EXEEXT"><tt>EXEEXT</tt></a><small>(configured)</small></dt>
772 <dd>Provides the extension to be used on executables built by the makefiles.
773 The value may be empty on platforms that do not use file extensions for
774 executables (e.g. Unix).</dd>
775 <dt><a name="FLEX"><tt>FLEX</tt></a><small>(configured)</small></dt>
776 <dd>Specifies the path to the <tt>flex</tt> tool.</dd>
777 <dt><a name="GCCLD"><tt>GCCLD</tt></a><small>(defaulted)</small></dt>
778 <dd>Specifies the path to the <tt>gccld</tt> tool.</dd>
779 <dt><a name="INSTALL"><tt>INSTALL</tt></a><small>(configured)</small></dt>
780 <dd>Specifies the path to the <tt>install</tt> tool.</dd>
781 <dt><a name="LDFLAGS"><tt>LDFLAGS</tt></a><small>(configured)</small></dt>
782 <dd>Allows users to specify additional flags to pass to the linker.</dd>
783 <dt><a name="LIBS"><tt>LIBS</tt></a><small>(configured)</small></dt>
784 <dd>The list of libraries that should be linked with each tool.</dd>
785 <dt><a name="LIBTOOL"><tt>LIBTOOL</tt></a><small>(configured)</small></dt>
786 <dd>Specifies the path to the <tt>libtool</tt> tool. This tool is renamed
787 <tt>mklib</tt> by the <tt>configure</tt> script and always located in the
788 <dt><a name="LLVMAS"><tt>LLVMAS</tt></a><small>(defaulted)</small></dt>
789 <dd>Specifies the path to the <tt>llvm-as</tt> tool.</dd>
790 <dt><a name="LLVMGCC"><tt>LLVMGCC</tt></a><small>(defaulted)</small></dt>
791 <dd>Specifies the path to the LLVM version of the GCC 'C' Compiler</dd>
792 <dt><a name="LLVMGXX"><tt>LLVMGXX</tt></a><small>(defaulted)</small></dt>
793 <dd>Specifies the path to the LLVM version of the GCC C++ Compiler</dd>
794 <dt><a name="LLVM_OBJ_ROOT"><tt>LLVM_OBJ_ROOT</tt></a><small>(configured)</small></dt>
795 <dd>Specifies the top directory into which the output of the build is
797 <dt><a name="LLVM_SRC_ROOT"><tt>LLVM_SRC_ROOT</tt></a><small>(configured)</small></dt>
798 <dd>Specifies the top directory in which the sources are found.</dd>
799 <dt><a name="LLVM_TARBALL_NAME"><tt>LLVM_TARBALL_NAME</tt></a><small>(configured)</small></dt>
800 <dd>Specifies the name of the distribution tarball to create. This is
801 configured from the name of the project and its version number.</dd>
802 <dt><a name="MKDIR"><tt>MKDIR</tt></a><small>(defaulted)</small></dt>
803 <dd>Specifies the path to the <tt>mkdir</tt> tool that creates
805 <dt><a name="PLATFORMSTRIPOPTS"><tt>PLATFORMSTRIPOPTS</tt></a></dt>
806 <dd>The options to provide to the linker to specify that a stripped (no
807 symbols) executable should be built.</dd>
808 <dt><a name="RANLIB"><tt>RANLIB</tt></a><small>(defaulted)</small></dt>
809 <dd>Specifies the path to the <tt>ranlib</tt> tool.</dd>
810 <dt><a name="RM"><tt>RM</tt></a><small>(defaulted)</small></dt>
811 <dd>Specifies the path to the <tt>rm</tt> tool.</dd>
812 <dt><a name="SED"><tt>SED</tt></a><small>(defaulted)</small></dt>
813 <dd>Specifies the path to the <tt>sed</tt> tool.</dd>
814 <dt><a name="SHLIBEXT"><tt>SHLIBEXT</tt></a><small>(configured)</small></dt>
815 <dd>Provides the filename extension to use for shared libraries.</dd>
816 <dt><a name="TBLGEN"><tt>TBLGEN</tt></a><small>(defaulted)</small></dt>
817 <dd>Specifies the path to the <tt>tblgen</tt> tool.</dd>
818 <dt><a name="TAR"><tt>TAR</tt></a><small>(defaulted)</small></dt>
819 <dd>Specifies the path to the <tt>tar</tt> tool.</dd>
820 <dt><a name="ZIP"><tt>ZIP</tt></a><small>(defaulted)</small></dt>
821 <dd>Specifies the path to the <tt>zip</tt> tool.</dd>
825 <!-- ======================================================================= -->
826 <div class="doc_subsection"><a name="getvars">Readable Variables</a></div>
827 <div class="doc_text">
828 <p>Variables listed in the table below can be used by the user's Makefile but
829 should not be changed. Changing the value will generally cause the build to go
830 wrong, so don't do it.</p>
832 <dt><a name="bindir"><tt>bindir</tt></a></dt>
833 <dd>The directory into which executables will ultimately be installed. This
834 value is derived from the <tt>--prefix</tt> option given to
835 <tt>configure</tt>.</dd>
836 <dt><a name="BuildMode"><tt>BuildMode</tt></a></dt>
837 <dd>The name of the type of build being performed: Debug, Release, or
839 <dt><a name="bytecode_libdir"><tt>bytecode_libdir</tt></a></dt>
840 <dd>The directory into which bytecode libraries will ultimately be installed.
841 This value is derived from the <tt>--prefix</tt> option given to
842 <tt>configure</tt>.</dd>
843 <dt><a name="ConfigureScriptFLAGS"><tt>ConfigureScriptFLAGS</tt></a></dt>
844 <dd>Additional flags given to the <tt>configure</tt> script when
846 <dt><a name="DistDir"><tt>DistDir</tt></a></dt>
847 <dd>The <em>current</em> directory for which a distribution copy is being
849 <dt><a name="Echo"><tt>Echo</tt></a></dt>
850 <dd>The LLVM Makefile System output command. This provides the
851 <tt>llvm[n]</tt> prefix and starts with @ so the command itself is not
852 printed by <tt>make</tt>.</dd>
853 <dt><a name="EchoCmd"><tt>EchoCmd</tt></a></dt>
854 <dd> Same as <a href="#Echo"><tt>Echo</tt></a> but without the leading @.
856 <dt><a name="includedir"><tt>includedir</tt></a></dt>
857 <dd>The directory into which include files will ultimately be installed.
858 This value is derived from the <tt>--prefix</tt> option given to
859 <tt>configure</tt>.</dd>
860 <dt><a name="libdir"><tt>libdir</tt></a></dt><dd></dd>
861 <dd>The directory into which native libraries will ultimately be installed.
862 This value is derived from the <tt>--prefix</tt> option given to
863 <tt>configure</tt>.</dd>
864 <dt><a name="LibDir"><tt>LibDir</tt></a></dt>
865 <dd>The configuration specific directory into which libraries are placed
866 before installation.</dd>
867 <dt><a name="MakefileConfig"><tt>MakefileConfig</tt></a></dt>
868 <dd>Full path of the <tt>Makefile.config</tt> file.</dd>
869 <dt><a name="MakefileConfigIn"><tt>MakefileConfigIn</tt></a></dt>
870 <dd>Full path of the <tt>Makefile.config.in</tt> file.</dd>
871 <dt><a name="ObjDir"><tt>ObjDir</tt></a></dt>
872 <dd>The configuration and directory specific directory where build objects
873 (compilation results) are placed.</dd>
874 <dt><a name="SubDirs"><tt>SubDirs</tt></a></dt>
875 <dd>The complete list of sub-directories of the current directory as
876 specified by other variables.</dd>
877 <dt><a name="Sources"><tt>Sources</tt></a></dt>
878 <dd>The complete list of source files.</dd>
879 <dt><a name="sysconfdir"><tt>sysconfdir</tt></a></dt>
880 <dd>The directory into which configuration files will ultimately be
881 installed. This value is derived from the <tt>--prefix</tt> option given to
882 <tt>configure</tt>.</dd>
883 <dt><a name="ToolDir"><tt>ToolDir</tt></a></dt>
884 <dd>The configuration specific directory into which executables are placed
885 before they are installed.</dd>
886 <dt><a name="TopDistDir"><tt>TopDistDir</tt></a></dt>
887 <dd>The top most directory into which the distribution files are copied.
889 <dt><a name="Verb"><tt>Verb</tt></a></dt>
890 <dd>Use this as the first thing on your build script lines to enable or
891 disable verbose mode. It expands to either an @ (quiet mode) or nothing
892 (verbose mode). </dd>
896 <!-- ======================================================================= -->
897 <div class="doc_subsection"><a name="intvars">Internal Variables</a></div>
898 <div class="doc_text">
899 <p>Variables listed below are used by the LLVM Makefile System
900 and considered internal. You should not use these variables under any
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