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