1 =================== 2 LLVM Makefile Guide 3 =================== 4 5 .. contents:: 6 :local: 7 8 Introduction 9 ============ 10 11 This document provides *usage* information about the LLVM makefile system. While 12 loosely patterned after the BSD makefile system, LLVM has taken a departure from 13 BSD in order to implement additional features needed by LLVM. Although makefile 14 systems, such as ``automake``, were attempted at one point, it has become clear 15 that the features needed by LLVM and the ``Makefile`` norm are too great to use 16 a more limited tool. Consequently, LLVM requires simply GNU Make 3.79, a widely 17 portable makefile processor. LLVM unabashedly makes heavy use of the features of 18 GNU Make so the dependency on GNU Make is firm. If you're not familiar with 19 ``make``, it is recommended that you read the `GNU Makefile Manual 20 <http://www.gnu.org/software/make/manual/make.html>`_. 21 22 While this document is rightly part of the `LLVM Programmer's 23 Manual <ProgrammersManual.html>`_, it is treated separately here because of the 24 volume of content and because it is often an early source of bewilderment for 25 new developers. 26 27 General Concepts 28 ================ 29 30 The LLVM Makefile System is the component of LLVM that is responsible for 31 building the software, testing it, generating distributions, checking those 32 distributions, installing and uninstalling, etc. It consists of a several files 33 throughout the source tree. These files and other general concepts are described 34 in this section. 35 36 Projects 37 -------- 38 39 The LLVM Makefile System is quite generous. It not only builds its own software, 40 but it can build yours too. Built into the system is knowledge of the 41 ``llvm/projects`` directory. Any directory under ``projects`` that has both a 42 ``configure`` script and a ``Makefile`` is assumed to be a project that uses the 43 LLVM Makefile system. Building software that uses LLVM does not require the 44 LLVM Makefile System nor even placement in the ``llvm/projects`` 45 directory. However, doing so will allow your project to get up and running 46 quickly by utilizing the built-in features that are used to compile LLVM. LLVM 47 compiles itself using the same features of the makefile system as used for 48 projects. 49 50 For complete details on setting up your projects configuration, simply mimic the 51 ``llvm/projects/sample`` project. Or for further details, consult the 52 `Projects <Projects.html>`_ page. 53 54 Variable Values 55 --------------- 56 57 To use the makefile system, you simply create a file named ``Makefile`` in your 58 directory and declare values for certain variables. The variables and values 59 that you select determine what the makefile system will do. These variables 60 enable rules and processing in the makefile system that automatically Do The 61 Right Thing (C). 62 63 Including Makefiles 64 ------------------- 65 66 Setting variables alone is not enough. You must include into your Makefile 67 additional files that provide the rules of the LLVM Makefile system. The various 68 files involved are described in the sections that follow. 69 70 ``Makefile`` 71 ^^^^^^^^^^^^ 72 73 Each directory to participate in the build needs to have a file named 74 ``Makefile``. This is the file first read by ``make``. It has three 75 sections: 76 77 #. Settable Variables --- Required that must be set first. 78 #. ``include $(LEVEL)/Makefile.common`` --- include the LLVM Makefile system. 79 #. Override Variables --- Override variables set by the LLVM Makefile system. 80 81 .. _$(LEVEL)/Makefile.common: 82 83 ``Makefile.common`` 84 ^^^^^^^^^^^^^^^^^^^ 85 86 Every project must have a ``Makefile.common`` file at its top source 87 directory. This file serves three purposes: 88 89 #. It includes the project's configuration makefile to obtain values determined 90 by the ``configure`` script. This is done by including the 91 `$(LEVEL)/Makefile.config`_ file. 92 93 #. It specifies any other (static) values that are needed throughout the 94 project. Only values that are used in all or a large proportion of the 95 project's directories should be placed here. 96 97 #. It includes the standard rules for the LLVM Makefile system, 98 `$(LLVM_SRC_ROOT)/Makefile.rules`_. This file is the *guts* of the LLVM 99 ``Makefile`` system. 100 101 .. _$(LEVEL)/Makefile.config: 102 103 ``Makefile.config`` 104 ^^^^^^^^^^^^^^^^^^^ 105 106 Every project must have a ``Makefile.config`` at the top of its *build* 107 directory. This file is **generated** by the ``configure`` script from the 108 pattern provided by the ``Makefile.config.in`` file located at the top of the 109 project's *source* directory. The contents of this file depend largely on what 110 configuration items the project uses, however most projects can get what they 111 need by just relying on LLVM's configuration found in 112 ``$(LLVM_OBJ_ROOT)/Makefile.config``. 113 114 .. _$(LLVM_SRC_ROOT)/Makefile.rules: 115 116 ``Makefile.rules`` 117 ^^^^^^^^^^^^^^^^^^ 118 119 This file, located at ``$(LLVM_SRC_ROOT)/Makefile.rules`` is the heart of the 120 LLVM Makefile System. It provides all the logic, dependencies, and rules for 121 building the targets supported by the system. What it does largely depends on 122 the values of ``make`` `variables`_ that have been set *before* 123 ``Makefile.rules`` is included. 124 125 Comments 126 ^^^^^^^^ 127 128 User ``Makefile``\s need not have comments in them unless the construction is 129 unusual or it does not strictly follow the rules and patterns of the LLVM 130 makefile system. Makefile comments are invoked with the pound (``#``) character. 131 The ``#`` character and any text following it, to the end of the line, are 132 ignored by ``make``. 133 134 Tutorial 135 ======== 136 137 This section provides some examples of the different kinds of modules you can 138 build with the LLVM makefile system. In general, each directory you provide will 139 build a single object although that object may be composed of additionally 140 compiled components. 141 142 Libraries 143 --------- 144 145 Only a few variable definitions are needed to build a regular library. 146 Normally, the makefile system will build all the software into a single 147 ``libname.o`` (pre-linked) object. This means the library is not searchable and 148 that the distinction between compilation units has been dissolved. Optionally, 149 you can ask for a shared library (.so) or archive library (.a) built. Archive 150 libraries are the default. For example: 151 152 .. code-block:: makefile 153 154 LIBRARYNAME = mylib 155 SHARED_LIBRARY = 1 156 ARCHIVE_LIBRARY = 1 157 158 says to build a library named ``mylib`` with both a shared library 159 (``mylib.so``) and an archive library (``mylib.a``) version. The contents of all 160 the libraries produced will be the same, they are just constructed differently. 161 Note that you normally do not need to specify the sources involved. The LLVM 162 Makefile system will infer the source files from the contents of the source 163 directory. 164 165 The ``LOADABLE_MODULE=1`` directive can be used in conjunction with 166 ``SHARED_LIBRARY=1`` to indicate that the resulting shared library should be 167 openable with the ``dlopen`` function and searchable with the ``dlsym`` function 168 (or your operating system's equivalents). While this isn't strictly necessary on 169 Linux and a few other platforms, it is required on systems like HP-UX and 170 Darwin. You should use ``LOADABLE_MODULE`` for any shared library that you 171 intend to be loaded into an tool via the ``-load`` option. `Pass documentation 172 <writing-an-llvm-pass-makefile>`_ has an example of why you might want to do 173 this. 174 175 Loadable Modules 176 ^^^^^^^^^^^^^^^^ 177 178 In some situations, you need to create a loadable module. Loadable modules can 179 be loaded into programs like ``opt`` or ``llc`` to specify additional passes to 180 run or targets to support. Loadable modules are also useful for debugging a 181 pass or providing a pass with another package if that pass can't be included in 182 LLVM. 183 184 LLVM provides complete support for building such a module. All you need to do is 185 use the ``LOADABLE_MODULE`` variable in your ``Makefile``. For example, to build 186 a loadable module named ``MyMod`` that uses the LLVM libraries ``LLVMSupport.a`` 187 and ``LLVMSystem.a``, you would specify: 188 189 .. code-block:: makefile 190 191 LIBRARYNAME := MyMod 192 LOADABLE_MODULE := 1 193 LINK_COMPONENTS := support system 194 195 Use of the ``LOADABLE_MODULE`` facility implies several things: 196 197 #. There will be no "``lib``" prefix on the module. This differentiates it from 198 a standard shared library of the same name. 199 200 #. The `SHARED_LIBRARY`_ variable is turned on. 201 202 #. The `LINK_LIBS_IN_SHARED`_ variable is turned on. 203 204 A loadable module is loaded by LLVM via the facilities of libtool's libltdl 205 library which is part of ``lib/System`` implementation. 206 207 Tools 208 ----- 209 210 For building executable programs (tools), you must provide the name of the tool 211 and the names of the libraries you wish to link with the tool. For example: 212 213 .. code-block:: makefile 214 215 TOOLNAME = mytool 216 USEDLIBS = mylib 217 LINK_COMPONENTS = support system 218 219 says that we are to build a tool name ``mytool`` and that it requires three 220 libraries: ``mylib``, ``LLVMSupport.a`` and ``LLVMSystem.a``. 221 222 Note that two different variables are used to indicate which libraries are 223 linked: ``USEDLIBS`` and ``LLVMLIBS``. This distinction is necessary to support 224 projects. ``LLVMLIBS`` refers to the LLVM libraries found in the LLVM object 225 directory. ``USEDLIBS`` refers to the libraries built by your project. In the 226 case of building LLVM tools, ``USEDLIBS`` and ``LLVMLIBS`` can be used 227 interchangeably since the "project" is LLVM itself and ``USEDLIBS`` refers to 228 the same place as ``LLVMLIBS``. 229 230 Also note that there are two different ways of specifying a library: with a 231 ``.a`` suffix and without. Without the suffix, the entry refers to the re-linked 232 (.o) file which will include *all* symbols of the library. This is 233 useful, for example, to include all passes from a library of passes. If the 234 ``.a`` suffix is used then the library is linked as a searchable library (with 235 the ``-l`` option). In this case, only the symbols that are unresolved *at 236 that point* will be resolved from the library, if they exist. Other 237 (unreferenced) symbols will not be included when the ``.a`` syntax is used. Note 238 that in order to use the ``.a`` suffix, the library in question must have been 239 built with the ``ARCHIVE_LIBRARY`` option set. 240 241 JIT Tools 242 ^^^^^^^^^ 243 244 Many tools will want to use the JIT features of LLVM. To do this, you simply 245 specify that you want an execution 'engine', and the makefiles will 246 automatically link in the appropriate JIT for the host or an interpreter if none 247 is available: 248 249 .. code-block:: makefile 250 251 TOOLNAME = my_jit_tool 252 USEDLIBS = mylib 253 LINK_COMPONENTS = engine 254 255 Of course, any additional libraries may be listed as other components. To get a 256 full understanding of how this changes the linker command, it is recommended 257 that you: 258 259 .. code-block:: bash 260 261 % cd examples/Fibonacci 262 % make VERBOSE=1 263 264 Targets Supported 265 ================= 266 267 This section describes each of the targets that can be built using the LLVM 268 Makefile system. Any target can be invoked from any directory but not all are 269 applicable to a given directory (e.g. "check", "dist" and "install" will always 270 operate as if invoked from the top level directory). 271 272 ================= =============== ================== 273 Target Name Implied Targets Target Description 274 ================= =============== ================== 275 ``all`` \ Compile the software recursively. Default target. 276 ``all-local`` \ Compile the software in the local directory only. 277 ``check`` \ Change to the ``test`` directory in a project and run the test suite there. 278 ``check-local`` \ Run a local test suite. Generally this is only defined in the ``Makefile`` of the project's ``test`` directory. 279 ``clean`` \ Remove built objects recursively. 280 ``clean-local`` \ Remove built objects from the local directory only. 281 ``dist`` ``all`` Prepare a source distribution tarball. 282 ``dist-check`` ``all`` Prepare a source distribution tarball and check that it builds. 283 ``dist-clean`` ``clean`` Clean source distribution tarball temporary files. 284 ``install`` ``all`` Copy built objects to installation directory. 285 ``preconditions`` ``all`` Check to make sure configuration and makefiles are up to date. 286 ``printvars`` ``all`` Prints variables defined by the makefile system (for debugging). 287 ``tags`` \ Make C and C++ tags files for emacs and vi. 288 ``uninstall`` \ Remove built objects from installation directory. 289 ================= =============== ================== 290 291 .. _all: 292 293 ``all`` (default) 294 ----------------- 295 296 When you invoke ``make`` with no arguments, you are implicitly instructing it to 297 seek the ``all`` target (goal). This target is used for building the software 298 recursively and will do different things in different directories. For example, 299 in a ``lib`` directory, the ``all`` target will compile source files and 300 generate libraries. But, in a ``tools`` directory, it will link libraries and 301 generate executables. 302 303 ``all-local`` 304 ------------- 305 306 This target is the same as `all`_ but it operates only on the current directory 307 instead of recursively. 308 309 ``check`` 310 --------- 311 312 This target can be invoked from anywhere within a project's directories but 313 always invokes the `check-local`_ target in the project's ``test`` directory, if 314 it exists and has a ``Makefile``. A warning is produced otherwise. If 315 `TESTSUITE`_ is defined on the ``make`` command line, it will be passed down to 316 the invocation of ``make check-local`` in the ``test`` directory. The intended 317 usage for this is to assist in running specific suites of tests. If 318 ``TESTSUITE`` is not set, the implementation of ``check-local`` should run all 319 normal tests. It is up to the project to define what different values for 320 ``TESTSUTE`` will do. See the :doc:`Testing Guide <TestingGuide>` for further 321 details. 322 323 ``check-local`` 324 --------------- 325 326 This target should be implemented by the ``Makefile`` in the project's ``test`` 327 directory. It is invoked by the ``check`` target elsewhere. Each project is 328 free to define the actions of ``check-local`` as appropriate for that 329 project. The LLVM project itself uses the :doc:`Lit <CommandGuide/lit>` testing 330 tool to run a suite of feature and regression tests. Other projects may choose 331 to use :program:`lit` or any other testing mechanism. 332 333 ``clean`` 334 --------- 335 336 This target cleans the build directory, recursively removing all things that the 337 Makefile builds. The cleaning rules have been made guarded so they shouldn't go 338 awry (via ``rm -f $(UNSET_VARIABLE)/*`` which will attempt to erase the entire 339 directory structure). 340 341 ``clean-local`` 342 --------------- 343 344 This target does the same thing as ``clean`` but only for the current (local) 345 directory. 346 347 ``dist`` 348 -------- 349 350 This target builds a distribution tarball. It first builds the entire project 351 using the ``all`` target and then tars up the necessary files and compresses 352 it. The generated tarball is sufficient for a casual source distribution, but 353 probably not for a release (see ``dist-check``). 354 355 ``dist-check`` 356 -------------- 357 358 This target does the same thing as the ``dist`` target but also checks the 359 distribution tarball. The check is made by unpacking the tarball to a new 360 directory, configuring it, building it, installing it, and then verifying that 361 the installation results are correct (by comparing to the original build). This 362 target can take a long time to run but should be done before a release goes out 363 to make sure that the distributed tarball can actually be built into a working 364 release. 365 366 ``dist-clean`` 367 -------------- 368 369 This is a special form of the ``clean`` clean target. It performs a normal 370 ``clean`` but also removes things pertaining to building the distribution. 371 372 ``install`` 373 ----------- 374 375 This target finalizes shared objects and executables and copies all libraries, 376 headers, executables and documentation to the directory given with the 377 ``--prefix`` option to ``configure``. When completed, the prefix directory will 378 have everything needed to **use** LLVM. 379 380 The LLVM makefiles can generate complete **internal** documentation for all the 381 classes by using ``doxygen``. By default, this feature is **not** enabled 382 because it takes a long time and generates a massive amount of data (>100MB). If 383 you want this feature, you must configure LLVM with the --enable-doxygen switch 384 and ensure that a modern version of doxygen (1.3.7 or later) is available in 385 your ``PATH``. You can download doxygen from `here 386 <http://www.stack.nl/~dimitri/doxygen/download.html#latestsrc>`_. 387 388 ``preconditions`` 389 ----------------- 390 391 This utility target checks to see if the ``Makefile`` in the object directory is 392 older than the ``Makefile`` in the source directory and copies it if so. It also 393 reruns the ``configure`` script if that needs to be done and rebuilds the 394 ``Makefile.config`` file similarly. Users may overload this target to ensure 395 that sanity checks are run *before* any building of targets as all the targets 396 depend on ``preconditions``. 397 398 ``printvars`` 399 ------------- 400 401 This utility target just causes the LLVM makefiles to print out some of the 402 makefile variables so that you can double check how things are set. 403 404 ``reconfigure`` 405 --------------- 406 407 This utility target will force a reconfigure of LLVM or your project. It simply 408 runs ``$(PROJ_OBJ_ROOT)/config.status --recheck`` to rerun the configuration 409 tests and rebuild the configured files. This isn't generally useful as the 410 makefiles will reconfigure themselves whenever its necessary. 411 412 ``spotless`` 413 ------------ 414 415 .. warning:: 416 417 Use with caution! 418 419 This utility target, only available when ``$(PROJ_OBJ_ROOT)`` is not the same as 420 ``$(PROJ_SRC_ROOT)``, will completely clean the ``$(PROJ_OBJ_ROOT)`` directory 421 by removing its content entirely and reconfiguring the directory. This returns 422 the ``$(PROJ_OBJ_ROOT)`` directory to a completely fresh state. All content in 423 the directory except configured files and top-level makefiles will be lost. 424 425 ``tags`` 426 -------- 427 428 This target will generate a ``TAGS`` file in the top-level source directory. It 429 is meant for use with emacs, XEmacs, or ViM. The TAGS file provides an index of 430 symbol definitions so that the editor can jump you to the definition 431 quickly. 432 433 ``uninstall`` 434 ------------- 435 436 This target is the opposite of the ``install`` target. It removes the header, 437 library and executable files from the installation directories. Note that the 438 directories themselves are not removed because it is not guaranteed that LLVM is 439 the only thing installing there (e.g. ``--prefix=/usr``). 440 441 .. _variables: 442 443 Variables 444 ========= 445 446 Variables are used to tell the LLVM Makefile System what to do and to obtain 447 information from it. Variables are also used internally by the LLVM Makefile 448 System. Variable names that contain only the upper case alphabetic letters and 449 underscore are intended for use by the end user. All other variables are 450 internal to the LLVM Makefile System and should not be relied upon nor 451 modified. The sections below describe how to use the LLVM Makefile 452 variables. 453 454 Control Variables 455 ----------------- 456 457 Variables listed in the table below should be set *before* the inclusion of 458 `$(LEVEL)/Makefile.common`_. These variables provide input to the LLVM make 459 system that tell it what to do for the current directory. 460 461 ``BUILD_ARCHIVE`` 462 If set to any value, causes an archive (.a) library to be built. 463 464 ``BUILT_SOURCES`` 465 Specifies a set of source files that are generated from other source 466 files. These sources will be built before any other target processing to 467 ensure they are present. 468 469 ``CONFIG_FILES`` 470 Specifies a set of configuration files to be installed. 471 472 ``DEBUG_SYMBOLS`` 473 If set to any value, causes the build to include debugging symbols even in 474 optimized objects, libraries and executables. This alters the flags 475 specified to the compilers and linkers. Debugging isn't fun in an optimized 476 build, but it is possible. 477 478 ``DIRS`` 479 Specifies a set of directories, usually children of the current directory, 480 that should also be made using the same goal. These directories will be 481 built serially. 482 483 ``DISABLE_AUTO_DEPENDENCIES`` 484 If set to any value, causes the makefiles to **not** automatically generate 485 dependencies when running the compiler. Use of this feature is discouraged 486 and it may be removed at a later date. 487 488 ``ENABLE_OPTIMIZED`` 489 If set to 1, causes the build to generate optimized objects, libraries and 490 executables. This alters the flags specified to the compilers and 491 linkers. Generally debugging won't be a fun experience with an optimized 492 build. 493 494 ``ENABLE_PROFILING`` 495 If set to 1, causes the build to generate both optimized and profiled 496 objects, libraries and executables. This alters the flags specified to the 497 compilers and linkers to ensure that profile data can be collected from the 498 tools built. Use the ``gprof`` tool to analyze the output from the profiled 499 tools (``gmon.out``). 500 501 ``DISABLE_ASSERTIONS`` 502 If set to 1, causes the build to disable assertions, even if building a 503 debug or profile build. This will exclude all assertion check code from the 504 build. LLVM will execute faster, but with little help when things go 505 wrong. 506 507 ``EXPERIMENTAL_DIRS`` 508 Specify a set of directories that should be built, but if they fail, it 509 should not cause the build to fail. Note that this should only be used 510 temporarily while code is being written. 511 512 ``EXPORTED_SYMBOL_FILE`` 513 Specifies the name of a single file that contains a list of the symbols to 514 be exported by the linker. One symbol per line. 515 516 ``EXPORTED_SYMBOL_LIST`` 517 Specifies a set of symbols to be exported by the linker. 518 519 ``EXTRA_DIST`` 520 Specifies additional files that should be distributed with LLVM. All source 521 files, all built sources, all Makefiles, and most documentation files will 522 be automatically distributed. Use this variable to distribute any files that 523 are not automatically distributed. 524 525 ``KEEP_SYMBOLS`` 526 If set to any value, specifies that when linking executables the makefiles 527 should retain debug symbols in the executable. Normally, symbols are 528 stripped from the executable. 529 530 ``LEVEL`` (required) 531 Specify the level of nesting from the top level. This variable must be set 532 in each makefile as it is used to find the top level and thus the other 533 makefiles. 534 535 ``LIBRARYNAME`` 536 Specify the name of the library to be built. (Required For Libraries) 537 538 ``LINK_COMPONENTS`` 539 When specified for building a tool, the value of this variable will be 540 passed to the ``llvm-config`` tool to generate a link line for the 541 tool. Unlike ``USEDLIBS`` and ``LLVMLIBS``, not all libraries need to be 542 specified. The ``llvm-config`` tool will figure out the library dependencies 543 and add any libraries that are needed. The ``USEDLIBS`` variable can still 544 be used in conjunction with ``LINK_COMPONENTS`` so that additional 545 project-specific libraries can be linked with the LLVM libraries specified 546 by ``LINK_COMPONENTS``. 547 548 .. _LINK_LIBS_IN_SHARED: 549 550 ``LINK_LIBS_IN_SHARED`` 551 By default, shared library linking will ignore any libraries specified with 552 the `LLVMLIBS`_ or `USEDLIBS`_. This prevents shared libs from including 553 things that will be in the LLVM tool the shared library will be loaded 554 into. However, sometimes it is useful to link certain libraries into your 555 shared library and this option enables that feature. 556 557 .. _LLVMLIBS: 558 559 ``LLVMLIBS`` 560 Specifies the set of libraries from the LLVM ``$(ObjDir)`` that will be 561 linked into the tool or library. 562 563 ``LOADABLE_MODULE`` 564 If set to any value, causes the shared library being built to also be a 565 loadable module. Loadable modules can be opened with the dlopen() function 566 and searched with dlsym (or the operating system's equivalent). Note that 567 setting this variable without also setting ``SHARED_LIBRARY`` will have no 568 effect. 569 570 ``NO_INSTALL`` 571 Specifies that the build products of the directory should not be installed 572 but should be built even if the ``install`` target is given. This is handy 573 for directories that build libraries or tools that are only used as part of 574 the build process, such as code generators (e.g. ``tblgen``). 575 576 ``OPTIONAL_DIRS`` 577 Specify a set of directories that may be built, if they exist, but it is 578 not an error for them not to exist. 579 580 ``PARALLEL_DIRS`` 581 Specify a set of directories to build recursively and in parallel if the 582 ``-j`` option was used with ``make``. 583 584 .. _SHARED_LIBRARY: 585 586 ``SHARED_LIBRARY`` 587 If set to any value, causes a shared library (``.so``) to be built in 588 addition to any other kinds of libraries. Note that this option will cause 589 all source files to be built twice: once with options for position 590 independent code and once without. Use it only where you really need a 591 shared library. 592 593 ``SOURCES`` (optional) 594 Specifies the list of source files in the current directory to be 595 built. Source files of any type may be specified (programs, documentation, 596 config files, etc.). If not specified, the makefile system will infer the 597 set of source files from the files present in the current directory. 598 599 ``SUFFIXES`` 600 Specifies a set of filename suffixes that occur in suffix match rules. Only 601 set this if your local ``Makefile`` specifies additional suffix match 602 rules. 603 604 ``TARGET`` 605 Specifies the name of the LLVM code generation target that the current 606 directory builds. Setting this variable enables additional rules to build 607 ``.inc`` files from ``.td`` files. 608 609 .. _TESTSUITE: 610 611 ``TESTSUITE`` 612 Specifies the directory of tests to run in ``llvm/test``. 613 614 ``TOOLNAME`` 615 Specifies the name of the tool that the current directory should build. 616 617 ``TOOL_VERBOSE`` 618 Implies ``VERBOSE`` and also tells each tool invoked to be verbose. This is 619 handy when you're trying to see the sub-tools invoked by each tool invoked 620 by the makefile. For example, this will pass ``-v`` to the GCC compilers 621 which causes it to print out the command lines it uses to invoke sub-tools 622 (compiler, assembler, linker). 623 624 .. _USEDLIBS: 625 626 ``USEDLIBS`` 627 Specifies the list of project libraries that will be linked into the tool or 628 library. 629 630 ``VERBOSE`` 631 Tells the Makefile system to produce detailed output of what it is doing 632 instead of just summary comments. This will generate a LOT of output. 633 634 Override Variables 635 ------------------ 636 637 Override variables can be used to override the default values provided by the 638 LLVM makefile system. These variables can be set in several ways: 639 640 * In the environment (e.g. setenv, export) --- not recommended. 641 * On the ``make`` command line --- recommended. 642 * On the ``configure`` command line. 643 * In the Makefile (only *after* the inclusion of `$(LEVEL)/Makefile.common`_). 644 645 The override variables are given below: 646 647 ``AR`` (defaulted) 648 Specifies the path to the ``ar`` tool. 649 650 ``PROJ_OBJ_DIR`` 651 The directory into which the products of build rules will be placed. This 652 might be the same as `PROJ_SRC_DIR`_ but typically is not. 653 654 .. _PROJ_SRC_DIR: 655 656 ``PROJ_SRC_DIR`` 657 The directory which contains the source files to be built. 658 659 ``BUILD_EXAMPLES`` 660 If set to 1, build examples in ``examples`` and (if building Clang) 661 ``tools/clang/examples`` directories. 662 663 ``BZIP2`` (configured) 664 The path to the ``bzip2`` tool. 665 666 ``CC`` (configured) 667 The path to the 'C' compiler. 668 669 ``CFLAGS`` 670 Additional flags to be passed to the 'C' compiler. 671 672 ``CPPFLAGS`` 673 Additional flags passed to the C/C++ preprocessor. 674 675 ``CXX`` 676 Specifies the path to the C++ compiler. 677 678 ``CXXFLAGS`` 679 Additional flags to be passed to the C++ compiler. 680 681 ``DATE`` (configured) 682 Specifies the path to the ``date`` program or any program that can generate 683 the current date and time on its standard output. 684 685 ``DOT`` (configured) 686 Specifies the path to the ``dot`` tool or ``false`` if there isn't one. 687 688 ``ECHO`` (configured) 689 Specifies the path to the ``echo`` tool for printing output. 690 691 ``EXEEXT`` (configured) 692 Provides the extension to be used on executables built by the makefiles. 693 The value may be empty on platforms that do not use file extensions for 694 executables (e.g. Unix). 695 696 ``INSTALL`` (configured) 697 Specifies the path to the ``install`` tool. 698 699 ``LDFLAGS`` (configured) 700 Allows users to specify additional flags to pass to the linker. 701 702 ``LIBS`` (configured) 703 The list of libraries that should be linked with each tool. 704 705 ``LIBTOOL`` (configured) 706 Specifies the path to the ``libtool`` tool. This tool is renamed ``mklib`` 707 by the ``configure`` script. 708 709 ``LLVMAS`` (defaulted) 710 Specifies the path to the ``llvm-as`` tool. 711 712 ``LLVMGCC`` (defaulted) 713 Specifies the path to the LLVM version of the GCC 'C' Compiler. 714 715 ``LLVMGXX`` (defaulted) 716 Specifies the path to the LLVM version of the GCC C++ Compiler. 717 718 ``LLVMLD`` (defaulted) 719 Specifies the path to the LLVM bitcode linker tool 720 721 ``LLVM_OBJ_ROOT`` (configured) 722 Specifies the top directory into which the output of the build is placed. 723 724 ``LLVM_SRC_ROOT`` (configured) 725 Specifies the top directory in which the sources are found. 726 727 ``LLVM_TARBALL_NAME`` (configured) 728 Specifies the name of the distribution tarball to create. This is configured 729 from the name of the project and its version number. 730 731 ``MKDIR`` (defaulted) 732 Specifies the path to the ``mkdir`` tool that creates directories. 733 734 ``ONLY_TOOLS`` 735 If set, specifies the list of tools to build. 736 737 ``PLATFORMSTRIPOPTS`` 738 The options to provide to the linker to specify that a stripped (no symbols) 739 executable should be built. 740 741 ``RANLIB`` (defaulted) 742 Specifies the path to the ``ranlib`` tool. 743 744 ``RM`` (defaulted) 745 Specifies the path to the ``rm`` tool. 746 747 ``SED`` (defaulted) 748 Specifies the path to the ``sed`` tool. 749 750 ``SHLIBEXT`` (configured) 751 Provides the filename extension to use for shared libraries. 752 753 ``TBLGEN`` (defaulted) 754 Specifies the path to the ``tblgen`` tool. 755 756 ``TAR`` (defaulted) 757 Specifies the path to the ``tar`` tool. 758 759 ``ZIP`` (defaulted) 760 Specifies the path to the ``zip`` tool. 761 762 Readable Variables 763 ------------------ 764 765 Variables listed in the table below can be used by the user's Makefile but 766 should not be changed. Changing the value will generally cause the build to go 767 wrong, so don't do it. 768 769 ``bindir`` 770 The directory into which executables will ultimately be installed. This 771 value is derived from the ``--prefix`` option given to ``configure``. 772 773 ``BuildMode`` 774 The name of the type of build being performed: Debug, Release, or 775 Profile. 776 777 ``bytecode_libdir`` 778 The directory into which bitcode libraries will ultimately be installed. 779 This value is derived from the ``--prefix`` option given to ``configure``. 780 781 ``ConfigureScriptFLAGS`` 782 Additional flags given to the ``configure`` script when reconfiguring. 783 784 ``DistDir`` 785 The *current* directory for which a distribution copy is being made. 786 787 .. _Echo: 788 789 ``Echo`` 790 The LLVM Makefile System output command. This provides the ``llvm[n]`` 791 prefix and starts with ``@`` so the command itself is not printed by 792 ``make``. 793 794 ``EchoCmd`` 795 Same as `Echo`_ but without the leading ``@``. 796 797 ``includedir`` 798 The directory into which include files will ultimately be installed. This 799 value is derived from the ``--prefix`` option given to ``configure``. 800 801 ``libdir`` 802 The directory into which native libraries will ultimately be installed. 803 This value is derived from the ``--prefix`` option given to 804 ``configure``. 805 806 ``LibDir`` 807 The configuration specific directory into which libraries are placed before 808 installation. 809 810 ``MakefileConfig`` 811 Full path of the ``Makefile.config`` file. 812 813 ``MakefileConfigIn`` 814 Full path of the ``Makefile.config.in`` file. 815 816 ``ObjDir`` 817 The configuration and directory specific directory where build objects 818 (compilation results) are placed. 819 820 ``SubDirs`` 821 The complete list of sub-directories of the current directory as 822 specified by other variables. 823 824 ``Sources`` 825 The complete list of source files. 826 827 ``sysconfdir`` 828 The directory into which configuration files will ultimately be 829 installed. This value is derived from the ``--prefix`` option given to 830 ``configure``. 831 832 ``ToolDir`` 833 The configuration specific directory into which executables are placed 834 before they are installed. 835 836 ``TopDistDir`` 837 The top most directory into which the distribution files are copied. 838 839 ``Verb`` 840 Use this as the first thing on your build script lines to enable or disable 841 verbose mode. It expands to either an ``@`` (quiet mode) or nothing (verbose 842 mode). 843 844 Internal Variables 845 ------------------ 846 847 Variables listed below are used by the LLVM Makefile System and considered 848 internal. You should not use these variables under any circumstances. 849 850 .. code-block:: makefile 851 852 Archive 853 AR.Flags 854 BaseNameSources 855 BCLinkLib 856 C.Flags 857 Compile.C 858 CompileCommonOpts 859 Compile.CXX 860 ConfigStatusScript 861 ConfigureScript 862 CPP.Flags 863 CPP.Flags 864 CXX.Flags 865 DependFiles 866 DestArchiveLib 867 DestBitcodeLib 868 DestModule 869 DestSharedLib 870 DestTool 871 DistAlways 872 DistCheckDir 873 DistCheckTop 874 DistFiles 875 DistName 876 DistOther 877 DistSources 878 DistSubDirs 879 DistTarBZ2 880 DistTarGZip 881 DistZip 882 ExtraLibs 883 FakeSources 884 INCFiles 885 InternalTargets 886 LD.Flags 887 LibName.A 888 LibName.BC 889 LibName.LA 890 LibName.O 891 LibTool.Flags 892 Link 893 LinkModule 894 LLVMLibDir 895 LLVMLibsOptions 896 LLVMLibsPaths 897 LLVMToolDir 898 LLVMUsedLibs 899 LocalTargets 900 Module 901 ObjectsLO 902 ObjectsO 903 ObjMakefiles 904 ParallelTargets 905 PreConditions 906 ProjLibsOptions 907 ProjLibsPaths 908 ProjUsedLibs 909 Ranlib 910 RecursiveTargets 911 SrcMakefiles 912 Strip 913 StripWarnMsg 914 TableGen 915 TDFiles 916 ToolBuildPath 917 TopLevelTargets 918 UserTargets 919
