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79 <!-- *********************************************************************** -->
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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
95 <p>While this document is rightly part of the
97 separately here because of the volume of content and because it is often an
98 early source of bewilderment for new developers.</p>
99 </div>
101 <!-- *********************************************************************** -->
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>
111 </div>
113 <!-- ======================================================================= -->
116 <p>The LLVM Makefile System is quite generous. It not only builds its own
117 software, but it can build yours too. Built into the system is knowledge of
120 to be a project that uses the LLVM Makefile system. Building software that
121 uses LLVM does not require the LLVM Makefile System nor even placement in the
123 to get up and running quickly by utilizing the built-in features that are used
124 to compile LLVM. LLVM compiles itself using the same features of the makefile
125 system as used for projects.</p>
126 <p>For complete details on setting up your projects configuration, simply
129 </div>
131 <!-- ======================================================================= -->
134 <p>To use the makefile system, you simply create a file named
136 The variables and values that you select determine what the makefile system
137 will do. These variables enable rules and processing in the makefile system
138 that automatically Do The Right Thing™.
139 </div>
141 <!-- ======================================================================= -->
144 <p>Setting variables alone is not enough. You must include into your Makefile
145 additional files that provide the rules of the LLVM Makefile system. The
146 various files involved are described in the sections that follow.</p>
147 </div>
149 <!-- ======================================================================= -->
152 <p>Each directory to participate in the build needs to have a file named
154 sections:</p>
155 <ol>
157 first.</li>
159 - include the LLVM Makefile system.
161 the LLVM Makefile system.
162 </ol>
163 </div>
165 <!-- ======================================================================= -->
167 </div>
170 directory. This file serves three purposes:</p>
171 <ol>
172 <li>It includes the project's configuration makefile to obtain values
175 <li>It specifies any other (static) values that are needed throughout the
176 project. Only values that are used in all or a large proportion of the
177 project's directories should be placed here.</li>
178 <li>It includes the standard rules for the LLVM Makefile system,
181 </ol>
182 </div>
184 <!-- ======================================================================= -->
186 </div>
193 configuration items the project uses, however most projects can get what they
194 need by just relying on LLVM's configuration found in
196 </div>
198 <!-- ======================================================================= -->
202 of the LLVM Makefile System. It provides all the logic, dependencies, and
203 rules for building the targets supported by the system. What it does largely
206 </div>
208 <!-- ======================================================================= -->
211 <p>User Makefiles need not have comments in them unless the construction is
212 unusual or it does not strictly follow the rules and patterns of the LLVM
213 makefile system. Makefile comments are invoked with the pound (#) character.
214 The # character and any text following it, to the end of the line, are ignored
216 </div>
218 <!-- *********************************************************************** -->
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>
226 </div>
228 <!-- ======================================================================= -->
231 <p>Only a few variable definitions are needed to build a regular library.
232 Normally, the makefile system will build all the software into a single
234 searchable and that the distinction between compilation units has been
235 dissolved. Optionally, you can ask for a shared library (.so), archive library
236 (.a) or to not have the default (relinked) library built. For example:</p>
237 <pre><tt>
238 LIBRARYNAME = mylib
239 SHARED_LIBRARY = 1
240 ARCHIVE_LIBRARY = 1
241 DONT_BUILD_RELINKED = 1
242 </tt></pre>
246 libraries produced will be the same, they are just constructed differently.
247 Note that you normally do not need to specify the sources involved. The LLVM
248 Makefile system will infer the source files from the contents of the source
249 directory.</p>
254 isn't strictly necessary on Linux and a few other platforms, it is required
256 any shared library that you intend to be loaded into an tool via the
259 for an example of why you might want to do this.
260 </div>
262 <!-- ======================================================================= -->
265 <p>In some situations, it is desireable to build a single bitcode module from
266 a variety of sources, instead of an archive, shared library, or bitcode
267 library. Bitcode modules can be specified in addition to any of the other
269 variable. For example:</p>
270 <pre><tt>
271 LIBRARYNAME = mylib
272 BYTECODE_LIBRARY = 1
273 MODULE_NAME = mymod
274 </tt></pre>
276 directory. This module will be an aggregation of all the bitcode modules
277 derived from the sources. The example will also build a bitcode archive
278 containing a bitcode module for each compiled source file. The difference is
279 subtle, but important depending on how the module or library is to be linked.
280 </p>
281 </div>
283 <!-- ======================================================================= -->
286 </div>
288 <p>In some situations, you need to create a loadable module. Loadable modules
290 additional passes to run or targets to support. Loadable modules are also
291 useful for debugging a pass or providing a pass with another package if that
292 pass can't be included in LLVM.</p>
293 <p>LLVM provides complete support for building such a module. All you need to
294 do is use the LOADABLE_MODULE variable in your Makefile. For example, to
297 <pre><tt>
298 LIBRARYNAME := MyMod
299 LOADABLE_MODULE := 1
300 LINK_COMPONENTS := support system
301 </tt></pre>
303 <ol>
305 a standard shared library of the same name.</li>
307 on.</li>
309 is turned on.</li>
311 is turned on.</li>
312 </ol>
313 <p>A loadable module is loaded by LLVM via the facilities of libtool's libltdl
315 </div>
317 <!-- ======================================================================= -->
320 <p>For building executable programs (tools), you must provide the name of the
321 tool and the names of the libraries you wish to link with the tool. For
322 example:</p>
323 <pre><tt>
324 TOOLNAME = mytool
325 USEDLIBS = mylib
326 LINK_COMPONENTS = support system
327 </tt></pre>
331 <p>Note that two different variables are use to indicate which libraries are
338 </p>
339 <p>Also note that there are two different ways of specifying a library: with a
342 This is useful, for example, to include all passes from a library of passes.
349 </p>
350 </div>
352 <!-- ======================================================================= -->
355 <p>Many tools will want to use the JIT features of LLVM. To do this, you
356 simply specify that you want an execution 'engine', and the makefiles will
357 automatically link in the appropriate JIT for the host or an interpreter
358 if none is available:</p>
359 <pre><tt>
360 TOOLNAME = my_jit_tool
361 USEDLIBS = mylib
362 LINK_COMPONENTS = engine
363 </tt></pre>
364 <p>Of course, any additional libraries may be listed as other components. To
365 get a full understanding of how this changes the linker command, it is
366 recommended that you:</p>
367 <pre><tt>
368 cd examples/Fibonacci
369 make VERBOSE=1
370 </tt></pre>
371 </div>
373 <!-- *********************************************************************** -->
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
381 always operate as if invoked from the top level directory).</p>
384 <tr>
386 </tr>
388 <td>Compile the software recursively. Default target.
389 </td></tr>
391 <td>Compile the software in the local directory only.
392 </td></tr>
395 test suite there.
396 </td></tr>
398 <td>Run a local test suite. Generally this is only defined in the
400 </td></tr>
402 <td>Remove built objects recursively.
403 </td></tr>
405 <td>Remove built objects from the local directory only.
406 </td></tr>
408 <td>Prepare a source distribution tarball.
409 </td></tr>
411 <td>Prepare a source distribution tarball and check that it builds.
412 </td></tr>
414 <td>Clean source distribution tarball temporary files.
415 </td></tr>
417 <td>Copy built objects to installation directory.
418 </td></tr>
420 <td>Check to make sure configuration and makefiles are up to date.
421 </td></tr>
423 <td>Prints variables defined by the makefile system (for debugging).
424 </td></tr>
426 <td>Make C and C++ tags files for emacs and vi.
427 </td></tr>
429 <td>Remove built objects from installation directory.
430 </td></tr>
431 </table>
432 </div>
434 <!-- ======================================================================= -->
438 instructing it to seek the "all" target (goal). This target is used for
439 building the software recursively and will do different things in different
442 directory, it will link libraries and generate executables.</p>
443 </div>
445 <!-- ======================================================================= -->
449 the current directory instead of recursively.</p>
450 </div>
452 <!-- ======================================================================= -->
455 <p>This target can be invoked from anywhere within a project's directories
460 command line, it will be passed down to the invocation of
462 for this is to assist in running specific suites of tests. If
464 should run all normal tests. It is up to the project to define what
467 </div>
469 <!-- ======================================================================= -->
475 appropriate for that project. The LLVM project itself uses dejagnu to run a
476 suite of feature and regresson tests. Other projects may choose to use
477 dejagnu or any other testing mechanism.</p>
478 </div>
480 <!-- ======================================================================= -->
483 <p>This target cleans the build directory, recursively removing all things
484 that the Makefile builds. The cleaning rules have been made guarded so they
486 to erase the entire directory structure.</p>
487 </div>
489 <!-- ======================================================================= -->
493 (local) directory.</p>
494 </div>
496 <!-- ======================================================================= -->
499 <p>This target builds a distribution tarball. It first builds the entire
501 compresses it. The generated tarball is sufficient for a casual source
503 </div>
505 <!-- ======================================================================= -->
509 the distribution tarball. The check is made by unpacking the tarball to a new
510 directory, configuring it, building it, installing it, and then verifying that
511 the installation results are correct (by comparing to the original build).
512 This target can take a long time to run but should be done before a release
513 goes out to make sure that the distributed tarball can actually be built into
514 a working release.</p>
515 </div>
517 <!-- ======================================================================= -->
522 distribution.</p>
523 </div>
525 <!-- ======================================================================= -->
528 <p>This target finalizes shared objects and executables and copies all
529 libraries, headers, executables and documentation to the directory given
536 with the --enable-doxygen switch and ensure that a modern version of doxygen
538 doxygen from
540 here</a>.
541 </div>
543 <!-- ======================================================================= -->
552 </div>
554 <!-- ======================================================================= -->
557 <p>This utility target just causes the LLVM makefiles to print out some of
558 the makefile variables so that you can double check how things are set. </p>
559 </div>
561 <!-- ======================================================================= -->
564 <p>This utility target will force a reconfigure of LLVM or your project. It
566 configuration tests and rebuild the configured files. This isn't generally
567 useful as the makefiles will reconfigure themselves whenever its necessary.
568 </p>
569 </div>
571 <!-- ======================================================================= -->
578 directory to a completely fresh state. All content in the directory except
579 configured files and top-level makefiles will be lost.</p>
581 </div>
583 <!-- ======================================================================= -->
587 directory. It is meant for use with emacs, XEmacs, or ViM. The TAGS file
588 provides an index of symbol definitions so that the editor can jump you to the
589 definition quickly. </p>
590 </div>
592 <!-- ======================================================================= -->
596 header, library and executable files from the installation directories. Note
597 that the directories themselves are not removed because it is not guaranteed
598 that LLVM is the only thing installing there (e.g. --prefix=/usr).</p>
599 </div>
601 <!-- *********************************************************************** -->
603 <!-- *********************************************************************** -->
605 <p>Variables are used to tell the LLVM Makefile System what to do and to
606 obtain information from it. Variables are also used internally by the LLVM
607 Makefile System. Variable names that contain only the upper case alphabetic
608 letters and underscore are intended for use by the end user. All other
609 variables are internal to the LLVM Makefile System and should not be relied
610 upon nor modified. The sections below describe how to use the LLVM Makefile
611 variables.</p>
612 </div>
614 <!-- ======================================================================= -->
619 These variables provide input to the LLVM make system that tell it what to do
620 for the current directory.</p>
621 <dl>
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>
633 <dd>Specifies a set of directories, usually children of the current
634 directory, that should also be made using the same goal. These directories
635 will be built serially.</dd>
638 generate dependencies when running the compiler. Use of this feature is
639 discouraged and it may be removed at a later date.</dd>
641 <dd>If set to any value, causes a relinked library (.o) not to be built. By
642 default, libraries are built as re-linked since most LLVM libraries are
643 needed in their entirety and re-linked libraries will be linked more quickly
644 than equivalent archive libraries.</dd>
646 <dd>If set to any value, 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
649 build.</dd>
651 <dd>If set to any value, 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
657 <dd>If set to any value, causes the build to disable assertions, even if
658 building a release 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>
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>
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>
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>
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>
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
682 makefiles.</dd>
684 <dd>Specify the name of the library to be built. (Required For
685 Libraries)</dd>
687 <dd>When specified for building a tool, the value of this variable will be
693 that additional project-specific libraries can be linked with the LLVM
696 <dd>By default, shared library linking will ignore any libraries specified
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
701 that feature.</dd>
703 <dd>Specifies the set of libraries from the LLVM $(ObjDir) that will be
704 linked into the tool or library.</dd>
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
710 no effect.</dd>
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
715 file.</dd>
717 <dd>Specifies that the build products of the directory should not be
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.
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>
726 <dd>Specify a set of directories to build recursively and in parallel if
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
733 shared library.</dd>
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>
740 <dd>Specifies a set of filename suffixes that occur in suffix match rules.
742 match rules.</dd>
744 <dd>Specifies the name of the LLVM code generation target that the
745 current directory builds. Setting this variable enables additional rules to
750 <dd>Specifies the name of the tool that the current directory should
751 build.</dd>
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
756 compilers which causes it to print out the command lines it uses to invoke
757 sub-tools (compiler, assembler, linker).</dd>
759 <dd>Specifies the list of project libraries that will be linked into the
760 tool or library.</dd>
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>
764 </dl>
765 </div>
767 <!-- ======================================================================= -->
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
772 several ways:</p>
773 <ul>
779 </ul>
781 <dl>
787 <dd>The directory into which the products of build rules will be placed.
788 This might be the same as
790 not.</dd>
805 generate the current date and time on its standard output</dd>
808 isn't one.</dd>
812 <dd>Provides the extension to be used on executables built by the makefiles.
813 The value may be empty on platforms that do not use file extensions for
814 executables (e.g. Unix).</dd>
835 </small></dt>
836 <dd>Specifies the top directory into which the output of the build is
837 placed.</dd>
839 </small></dt>
843 <dd>Specifies the name of the distribution tarball to create. This is
844 configured from the name of the project and its version number.</dd>
847 directories.</dd>
849 <dd>The options to provide to the linker to specify that a stripped (no
850 symbols) executable should be built.</dd>
865 </dl>
866 </div>
868 <!-- ======================================================================= -->
871 <p>Variables listed in the table below can be used by the user's Makefile but
872 should not be changed. Changing the value will generally cause the build to go
873 wrong, so don't do it.</p>
874 <dl>
876 <dd>The directory into which executables will ultimately be installed. This
880 <dd>The name of the type of build being performed: Debug, Release, or
881 Profile</dd>
883 <dd>The directory into which bitcode libraries will ultimately be
888 reconfiguring.</dd>
891 made.</dd>
893 <dd>The LLVM Makefile System output command. This provides the
898 </dd>
900 <dd>The directory into which include files will ultimately be installed.
904 <dd>The directory into which native libraries will ultimately be installed.
908 <dd>The configuration specific directory into which libraries are placed
909 before installation.</dd>
915 <dd>The configuration and directory specific directory where build objects
916 (compilation results) are placed.</dd>
918 <dd>The complete list of sub-directories of the current directory as
919 specified by other variables.</dd>
923 <dd>The directory into which configuration files will ultimately be
927 <dd>The configuration specific directory into which executables are placed
928 before they are installed.</dd>
930 <dd>The top most directory into which the distribution files are copied.
931 </dd>
933 <dd>Use this as the first thing on your build script lines to enable or
934 disable verbose mode. It expands to either an @ (quiet mode) or nothing
935 (verbose mode). </dd>
936 </dl>
937 </div>
939 <!-- ======================================================================= -->
942 <p>Variables listed below are used by the LLVM Makefile System
943 and considered internal. You should not use these variables under any
944 circumstances.</p>
945 <p><tt>
946 Archive
947 AR.Flags
948 BaseNameSources
949 BCCompile.C
950 BCCompile.CXX
951 BCLinkLib
952 C.Flags
953 Compile.C
954 CompileCommonOpts
955 Compile.CXX
956 ConfigStatusScript
957 ConfigureScript
958 CPP.Flags
959 CPP.Flags
960 CXX.Flags
961 DependFiles
962 DestArchiveLib
963 DestBitcodeLib
964 DestModule
965 DestRelinkedLib
966 DestSharedLib
967 DestTool
968 DistAlways
969 DistCheckDir
970 DistCheckTop
971 DistFiles
972 DistName
973 DistOther
974 DistSources
975 DistSubDirs
976 DistTarBZ2
977 DistTarGZip
978 DistZip
979 ExtraLibs
980 FakeSources
981 INCFiles
982 InternalTargets
983 LD.Flags
984 LexFiles
985 LexOutput
986 LibName.A
987 LibName.BC
988 LibName.LA
989 LibName.O
990 LibTool.Flags
991 Link
992 LinkModule
993 LLVMLibDir
994 LLVMLibsOptions
995 LLVMLibsPaths
996 LLVMToolDir
997 LLVMUsedLibs
998 LocalTargets
999 LTCompile.C
1000 LTCompile.CXX
1001 LTInstall
1002 Module
1003 ObjectsBC
1004 ObjectsLO
1005 ObjectsO
1006 ObjMakefiles
1007 ParallelTargets
1008 PreConditions
1009 ProjLibsOptions
1010 ProjLibsPaths
1011 ProjUsedLibs
1012 Ranlib
1013 RecursiveTargets
1014 Relink
1015 SrcMakefiles
1016 Strip
1017 StripWarnMsg
1018 TableGen
1019 TDFiles
1020 ToolBuildPath
1021 TopLevelTargets
1022 UserTargets
1023 YaccFiles
1024 YaccOutput
1025 </tt></p>
1026 </div>
1028 <!-- *********************************************************************** -->
1029 <hr>
1030 <address>
1038 Last modified: $Date$
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