[docs] Improvements to CMake.rst

- Fix some grammatical and typographical errors.
- Try to improve upon some awkward/nonstandard phrasings.
- Expand slightly the treatment of how you specify arguments to cmake.
- Update the list of possible LLVM_BUILD_TESTS and state where to find the
  definitive list.
- Correct the name of llvm-tblgen.
- Expand slightly the treatment of several build options, including
  LLVM_LIT_TOOLS_DIR, LLVM_ENABLE_FFI, and LLVM_EXTERNAL_project_SOURCE_DIR.

Patch by Brian R. Gaeke!

Differential Revision: http://reviews.llvm.org/D11862

llvm-svn: 245911

llvm/docs/CMake.rst

@@ -10,11 +10,11 @@ Introduction
 
 `CMake <http://www.cmake.org/>`_ is a cross-platform build-generator tool. CMake
 does not build the project, it generates the files needed by your build tool
-(GNU make, Visual Studio, etc) for building LLVM.
+(GNU make, Visual Studio, etc.) for building LLVM.
 
 If you are really anxious about getting a functional LLVM build, go to the
-`Quick start`_ section. If you are a CMake novice, start on `Basic CMake usage`_
+`Quick start`_ section. If you are a CMake novice, start with `Basic CMake usage`_
-and then go back to the `Quick start`_ once you know what you are doing. The
+and then go back to the `Quick start`_ section once you know what you are doing. The
 `Options and variables`_ section is a reference for customizing your build. If
 you already have experience with CMake, this is the recommended starting point.
 
@@ -31,35 +31,35 @@ We use here the command-line, non-interactive CMake interface.
 #. Open a shell. Your development tools must be reachable from this shell
    through the PATH environment variable.
 
-#. Create a directory for containing the build. It is not supported to build
+#. Create a build directory. Building LLVM in the source
-   LLVM on the source directory. cd to this directory:
+   directory is not supported. cd to this directory:
 
    .. code-block:: console
 
      $ mkdir mybuilddir
      $ cd mybuilddir
 
-#. Execute this command on the shell replacing `path/to/llvm/source/root` with
+#. Execute this command in the shell replacing `path/to/llvm/source/root` with
    the path to the root of your LLVM source tree:
 
    .. code-block:: console
 
      $ cmake path/to/llvm/source/root
 
-   CMake will detect your development environment, perform a series of test and
+   CMake will detect your development environment, perform a series of tests, and
    generate the files required for building LLVM. CMake will use default values
    for all build parameters. See the `Options and variables`_ section for
-   fine-tuning your build
+   a list of build parameters that you can modify.
 
    This can fail if CMake can't detect your toolset, or if it thinks that the
-   environment is not sane enough. On this case make sure that the toolset that
+   environment is not sane enough. In this case, make sure that the toolset that
-   you intend to use is the only one reachable from the shell and that the shell
+   you intend to use is the only one reachable from the shell, and that the shell
-   itself is the correct one for you development environment. CMake will refuse
+   itself is the correct one for your development environment. CMake will refuse
    to build MinGW makefiles if you have a POSIX shell reachable through the PATH
    environment variable, for instance. You can force CMake to use a given build
-   tool, see the `Usage`_ section.
+   tool; for instructions, see the `Usage`_ section, below.
 
-#. After CMake has finished running, proceed to use IDE project files or start
+#. After CMake has finished running, proceed to use IDE project files, or start
    the build from the build directory:
 
    .. code-block:: console
@@ -67,9 +67,9 @@ We use here the command-line, non-interactive CMake interface.
      $ cmake --build .
 
    The ``--build`` option tells ``cmake`` to invoke the underlying build
-   tool (``make``, ``ninja``, ``xcodebuild``, ``msbuild``, etc).
+   tool (``make``, ``ninja``, ``xcodebuild``, ``msbuild``, etc.)
 
-   The underlying build tool can be invoked directly either of course, but
+   The underlying build tool can be invoked directly, of course, but
    the ``--build`` option is portable.
 
 #. After LLVM has finished building, install it from the build directory:
@@ -95,33 +95,39 @@ We use here the command-line, non-interactive CMake interface.
 Basic CMake usage
 =================
 
-This section explains basic aspects of CMake, mostly for explaining those
+This section explains basic aspects of CMake
-options which you may need on your day-to-day usage.
+which you may need in your day-to-day usage.
 
-CMake comes with extensive documentation in the form of html files and on the
+CMake comes with extensive documentation, in the form of html files, and as
-cmake executable itself. Execute ``cmake --help`` for further help options.
+online help accessible via the ``cmake`` executable itself. Execute ``cmake
+--help`` for further help options.
 
-CMake requires to know for which build tool it shall generate files (GNU make,
+CMake allows you to specify a build tool (e.g., GNU make, Visual Studio,
-Visual Studio, Xcode, etc). If not specified on the command line, it tries to
+or Xcode). If not specified on the command line, CMake tries to guess which
-guess it based on you environment. Once identified the build tool, CMake uses
+build tool to use, based on your environment. Once it has identified your
-the corresponding *Generator* for creating files for your build tool. You can
+build tool, CMake uses the corresponding *Generator* to create files for your
+build tool (e.g., Makefiles or Visual Studio or Xcode project files). You can
 explicitly specify the generator with the command line option ``-G "Name of the
-generator"``. For knowing the available generators on your platform, execute
+generator"``. To see a list of the available generators on your system, execute
 
 .. code-block:: console
 
   $ cmake --help
 
-This will list the generator's names at the end of the help text. Generator's
+This will list the generator names at the end of the help text.
-names are case-sensitive. Example:
+
+Generators' names are case-sensitive, and may contain spaces. For this reason,
+you should enter them exactly as they are listed in the ``cmake --help``
+output, in quotes. For example, to generate project files specifically for
+Visual Studio 12, you can execute:
 
 .. code-block:: console
 
-  $ cmake -G "Visual Studio 11" path/to/llvm/source/root
+  $ cmake -G "Visual Studio 12" path/to/llvm/source/root
 
 For a given development platform there can be more than one adequate
-generator. If you use Visual Studio "NMake Makefiles" is a generator you can use
+generator. If you use Visual Studio, "NMake Makefiles" is a generator you can use
-for building with NMake. By default, CMake chooses the more specific generator
+for building with NMake. By default, CMake chooses the most specific generator
 supported by your development environment. If you want an alternative generator,
 you must tell this to CMake with the ``-G`` option.
 
@@ -142,18 +148,20 @@ CMake command line like this:
 
   $ cmake -DVARIABLE=value path/to/llvm/source
 
-You can set a variable after the initial CMake invocation for changing its
+You can set a variable after the initial CMake invocation to change its
 value. You can also undefine a variable:
 
 .. code-block:: console
 
   $ cmake -UVARIABLE path/to/llvm/source
 
-Variables are stored on the CMake cache. This is a file named ``CMakeCache.txt``
+Variables are stored in the CMake cache. This is a file named ``CMakeCache.txt``
-on the root of the build directory. Do not hand-edit it.
+stored at the root of your build directory that is generated by ``cmake``.
+Editing it yourself is not recommended.
 
-Variables are listed here appending its type after a colon. It is correct to
+Variables are listed in the CMake cache and later in this document with
-write the variable and the type on the CMake command line:
+the variable name and type separated by a colon. You can also specify the
+variable and type on the CMake command line:
 
 .. code-block:: console
 
@@ -163,17 +171,17 @@ Frequently-used CMake variables
 -------------------------------
 
 Here are some of the CMake variables that are used often, along with a
-brief explanation and LLVM-specific notes. For full documentation, check the
+brief explanation and LLVM-specific notes. For full documentation, consult the
-CMake docs or execute ``cmake --help-variable VARIABLE_NAME``.
+CMake manual, or execute ``cmake --help-variable VARIABLE_NAME``.
 
 **CMAKE_BUILD_TYPE**:STRING
-  Sets the build type for ``make`` based generators. Possible values are
+  Sets the build type for ``make``-based generators. Possible values are
-  Release, Debug, RelWithDebInfo and MinSizeRel. On systems like Visual Studio
+  Release, Debug, RelWithDebInfo and MinSizeRel. If you are using an IDE such as
-  the user sets the build type with the IDE settings.
+  Visual Studio, you should use the IDE settings to set the build type.
 
 **CMAKE_INSTALL_PREFIX**:PATH
   Path where LLVM will be installed if "make install" is invoked or the
-  "INSTALL" target is built.
+  "install" target is built.
 
 **LLVM_LIBDIR_SUFFIX**:STRING
   Extra suffix to append to the directory where libraries are to be
@@ -188,8 +196,9 @@ CMake docs or execute ``cmake --help-variable VARIABLE_NAME``.
 
 **BUILD_SHARED_LIBS**:BOOL
   Flag indicating if shared libraries will be built. Its default value is
-  OFF. Shared libraries are not supported on Windows and not recommended on the
+  OFF. This option is only recommended for use by LLVM developers.
-  other OSes.
+  On Windows, shared libraries may be used when building with MinGW, including
+  mingw-w64, but not when building with the Microsoft toolchain.
 
 .. _LLVM-specific variables:
 
@@ -203,13 +212,13 @@ LLVM-specific variables
 
 **LLVM_BUILD_TOOLS**:BOOL
   Build LLVM tools. Defaults to ON. Targets for building each tool are generated
-  in any case. You can build an tool separately by invoking its target. For
+  in any case. You can build a tool separately by invoking its target. For
-  example, you can build *llvm-as* with a makefile-based system executing *make
+  example, you can build *llvm-as* with a Makefile-based system by executing *make
-  llvm-as* on the root of your build directory.
+  llvm-as* at the root of your build directory.
 
 **LLVM_INCLUDE_TOOLS**:BOOL
-  Generate build targets for the LLVM tools. Defaults to ON. You can use that
+  Generate build targets for the LLVM tools. Defaults to ON. You can use this
-  option for disabling the generation of build targets for the LLVM tools.
+  option to disable the generation of build targets for the LLVM tools.
 
 **LLVM_BUILD_EXAMPLES**:BOOL
   Build LLVM examples. Defaults to OFF. Targets for building each example are
@@ -217,20 +226,20 @@ LLVM-specific variables
   details.
 
 **LLVM_INCLUDE_EXAMPLES**:BOOL
-  Generate build targets for the LLVM examples. Defaults to ON. You can use that
+  Generate build targets for the LLVM examples. Defaults to ON. You can use this
-  option for disabling the generation of build targets for the LLVM examples.
+  option to disable the generation of build targets for the LLVM examples.
 
 **LLVM_BUILD_TESTS**:BOOL
   Build LLVM unit tests. Defaults to OFF. Targets for building each unit test
-  are generated in any case. You can build a specific unit test with the target
+  are generated in any case. You can build a specific unit test using the
-  *UnitTestNameTests* (where at this time *UnitTestName* can be ADT, Analysis,
+  targets defined under *unittests*, such as ADTTests, IRTests, SupportTests,
-  ExecutionEngine, JIT, Support, Transform, VMCore; see the subdirectories of
+  etc. (Search for ``add_llvm_unittest`` in the subdirectories of *unittests*
-  *unittests* for an updated list.) It is possible to build all unit tests with
+  for a complete list of unit tests.) It is possible to build all unit tests
-  the target *UnitTests*.
+  with the target *UnitTests*.
 
 **LLVM_INCLUDE_TESTS**:BOOL
   Generate build targets for the LLVM unit tests. Defaults to ON. You can use
-  that option for disabling the generation of build targets for the LLVM unit
+  this option to disable the generation of build targets for the LLVM unit
   tests.
 
 **LLVM_APPEND_VC_REV**:BOOL
@@ -249,39 +258,39 @@ LLVM-specific variables
   is *Debug*.
 
 **LLVM_ENABLE_EH**:BOOL
-  Build LLVM with exception handling support. This is necessary if you wish to
+  Build LLVM with exception-handling support. This is necessary if you wish to
   link against LLVM libraries and make use of C++ exceptions in your own code
   that need to propagate through LLVM code. Defaults to OFF.
 
 **LLVM_ENABLE_PIC**:BOOL
-  Add the ``-fPIC`` flag for the compiler command-line, if the compiler supports
+  Add the ``-fPIC`` flag to the compiler command-line, if the compiler supports
   this flag. Some systems, like Windows, do not need this flag. Defaults to ON.
 
 **LLVM_ENABLE_RTTI**:BOOL
-  Build LLVM with run time type information. Defaults to OFF.
+  Build LLVM with run-time type information. Defaults to OFF.
 
 **LLVM_ENABLE_WARNINGS**:BOOL
   Enable all compiler warnings. Defaults to ON.
 
 **LLVM_ENABLE_PEDANTIC**:BOOL
-  Enable pedantic mode. This disables compiler specific extensions, if
+  Enable pedantic mode. This disables compiler-specific extensions, if
   possible. Defaults to ON.
 
 **LLVM_ENABLE_WERROR**:BOOL
-  Stop and fail build, if a compiler warning is triggered. Defaults to OFF.
+  Stop and fail the build, if a compiler warning is triggered. Defaults to OFF.
 
 **LLVM_ABI_BREAKING_CHECKS**:STRING
   Used to decide if LLVM should be built with ABI breaking checks or
   not.  Allowed values are `WITH_ASSERTS` (default), `FORCE_ON` and
   `FORCE_OFF`.  `WITH_ASSERTS` turns on ABI breaking checks in an
   assertion enabled build.  `FORCE_ON` (`FORCE_OFF`) turns them on
-  (off) irrespective of whether normal (`NDEBUG` based) assertions are
+  (off) irrespective of whether normal (`NDEBUG`-based) assertions are
   enabled or not.  A version of LLVM built with ABI breaking checks
   is not ABI compatible with a version built without it.
 
 **LLVM_BUILD_32_BITS**:BOOL
-  Build 32-bits executables and libraries on 64-bits systems. This option is
+  Build 32-bit executables and libraries on 64-bit systems. This option is
-  available only on some 64-bits unix systems. Defaults to OFF.
+  available only on some 64-bit Unix systems. Defaults to OFF.
 
 **LLVM_TARGET_ARCH**:STRING
   LLVM target to use for native code generation. This is required for JIT
@@ -290,7 +299,7 @@ LLVM-specific variables
   to the target architecture name.
 
 **LLVM_TABLEGEN**:STRING
-  Full path to a native TableGen executable (usually named ``tblgen``). This is
+  Full path to a native TableGen executable (usually named ``llvm-tblgen``). This is
   intended for cross-compiling: if the user sets this variable, no native
   TableGen will be created.
 
@@ -300,29 +309,36 @@ LLVM-specific variables
   others.
 
 **LLVM_LIT_TOOLS_DIR**:PATH
-  The path to GnuWin32 tools for tests. Valid on Windows host.  Defaults to "",
+  The path to GnuWin32 tools for tests. Valid on Windows host.  Defaults to
-  then Lit seeks tools according to %PATH%.  Lit can find tools(eg. grep, sort,
+  the empty string, in which case lit will look for tools needed for tests
-  &c) on LLVM_LIT_TOOLS_DIR at first, without specifying GnuWin32 to %PATH%.
+  (e.g. ``grep``, ``sort``, etc.) in your %PATH%. If GnuWin32 is not in your
+  %PATH%, then you can set this variable to the GnuWin32 directory so that
+  lit can find tools needed for tests in that directory.
 
 **LLVM_ENABLE_FFI**:BOOL
-  Indicates whether LLVM Interpreter will be linked with Foreign Function
+  Indicates whether the LLVM Interpreter will be linked with the Foreign Function
-  Interface library. If the library or its headers are installed on a custom
+  Interface library (libffi) in order to enable calling external functions.
-  location, you can set the variables FFI_INCLUDE_DIR and
+  If the library or its headers are installed in a custom
-  FFI_LIBRARY_DIR. Defaults to OFF.
+  location, you can also set the variables FFI_INCLUDE_DIR and
+  FFI_LIBRARY_DIR to the directories where ffi.h and libffi.so can be found,
+  respectively. Defaults to OFF.
 
 **LLVM_EXTERNAL_{CLANG,LLD,POLLY}_SOURCE_DIR**:PATH
-  Path to ``{Clang,lld,Polly}``\'s source directory. Defaults to
+  These variables specify the path to the source directory for the external
-  ``tools/{clang,lld,polly}``. ``{Clang,lld,Polly}`` will not be built when it
+  LLVM projects Clang, lld, and Polly, respectively, relative to the top-level
-  is empty or it does not point to a valid path.
+  source directory.  If the in-tree subdirectory for an external project
+  exists (e.g., llvm/tools/clang for Clang), then the corresponding variable
+  will not be used.  If the variable for an external project does not point
+  to a valid path, then that project will not be built.
 
 **LLVM_USE_OPROFILE**:BOOL
-  Enable building OProfile JIT support. Defaults to OFF
+  Enable building OProfile JIT support. Defaults to OFF.
 
 **LLVM_USE_INTEL_JITEVENTS**:BOOL
-  Enable building support for Intel JIT Events API. Defaults to OFF
+  Enable building support for Intel JIT Events API. Defaults to OFF.
 
 **LLVM_ENABLE_ZLIB**:BOOL
-  Build with zlib to support compression/uncompression in LLVM tools.
+  Enable building with zlib to support compression/uncompression in LLVM tools.
   Defaults to ON.
 
 **LLVM_USE_SANITIZER**:STRING
@@ -361,14 +377,14 @@ LLVM-specific variables
   ``org.llvm.qch``.
   This option is only useful in combination with
   ``-DLLVM_ENABLE_DOXYGEN_QT_HELP=ON``;
-  otherwise this has no effect.
+  otherwise it has no effect.
 
 **LLVM_DOXYGEN_QHP_NAMESPACE**:STRING
   Namespace under which the intermediate Qt Help Project file lives. See `Qt
   Help Project`_
   for more information. Defaults to "org.llvm". This option is only useful in
   combination with ``-DLLVM_ENABLE_DOXYGEN_QT_HELP=ON``; otherwise
-  this has no effect.
+  it has no effect.
 
 **LLVM_DOXYGEN_QHP_CUST_FILTER_NAME**:STRING
   See `Qt Help Project`_ for
@@ -377,14 +393,14 @@ LLVM-specific variables
   be used in Qt Creator to select only documentation from LLVM when browsing
   through all the help files that you might have loaded. This option is only
   useful in combination with ``-DLLVM_ENABLE_DOXYGEN_QT_HELP=ON``;
-  otherwise this has no effect.
+  otherwise it has no effect.
 
 .. _Qt Help Project: http://qt-project.org/doc/qt-4.8/qthelpproject.html#custom-filters
 
 **LLVM_DOXYGEN_QHELPGENERATOR_PATH**:STRING
   The path to the ``qhelpgenerator`` executable. Defaults to whatever CMake's
   ``find_program()`` can find. This option is only useful in combination with
-  ``-DLLVM_ENABLE_DOXYGEN_QT_HELP=ON``; otherwise this has no
+  ``-DLLVM_ENABLE_DOXYGEN_QT_HELP=ON``; otherwise it has no
   effect.
 
 **LLVM_DOXYGEN_SVG**:BOOL
@@ -419,15 +435,15 @@ LLVM-specific variables
 Executing the test suite
 ========================
 
-Testing is performed when the *check* target is built. For instance, if you are
+Testing is performed when the *check-all* target is built. For instance, if you are
-using makefiles, execute this command while on the top level of your build
+using Makefiles, execute this command in the root of your build directory:
-directory:
 
 .. code-block:: console
 
-  $ make check
+  $ make check-all
 
-On Visual Studio, you may run tests to build the project "check".
+On Visual Studio, you may run tests by building the project "check-all".
+For more information about testing, see the :doc:`TestingGuide`.
 
 Cross compiling
 ===============
@@ -447,10 +463,10 @@ Embedding LLVM in your project
 
 From LLVM 3.5 onwards both the CMake and autoconf/Makefile build systems export
 LLVM libraries as importable CMake targets. This means that clients of LLVM can
-now reliably use CMake to develop their own LLVM based projects against an
+now reliably use CMake to develop their own LLVM-based projects against an
 installed version of LLVM regardless of how it was built.
 
-Here is a simple example of CMakeLists.txt file that imports the LLVM libraries
+Here is a simple example of a CMakeLists.txt file that imports the LLVM libraries
 and uses them to build a simple application ``simple-tool``.
 
 .. code-block:: cmake
@@ -495,8 +511,8 @@ This file is available in two different locations.
   On Linux typically this is ``/usr/share/llvm/cmake/LLVMConfig.cmake``.
 
 * ``<LLVM_BUILD_ROOT>/share/llvm/cmake/LLVMConfig.cmake`` where
-  ``<LLVM_BUILD_ROOT>`` is the root of the LLVM build tree. **Note this only
+  ``<LLVM_BUILD_ROOT>`` is the root of the LLVM build tree. **Note: this is only
-  available when building LLVM with CMake**
+  available when building LLVM with CMake.**
 
 If LLVM is installed in your operating system's normal installation prefix (e.g.
 on Linux this is usually ``/usr/``) ``find_package(LLVM ...)`` will
@@ -529,7 +545,7 @@ include
   A list of include paths to directories containing LLVM header files.
 
 ``LLVM_PACKAGE_VERSION``
-  The LLVM version. This string can be used with CMake conditionals. E.g. ``if
+  The LLVM version. This string can be used with CMake conditionals, e.g., ``if
   (${LLVM_PACKAGE_VERSION} VERSION_LESS "3.5")``.
 
 ``LLVM_TOOLS_BINARY_DIR``
@@ -582,7 +598,7 @@ Contents of ``<project dir>/<pass name>/CMakeLists.txt``:
 
 Note if you intend for this pass to be merged into the LLVM source tree at some
 point in the future it might make more sense to use LLVM's internal
-add_llvm_loadable_module function instead by...
+``add_llvm_loadable_module`` function instead by...
 
 
 Adding the following to ``<project dir>/CMakeLists.txt`` (after
@@ -602,7 +618,7 @@ And then changing ``<project dir>/<pass name>/CMakeLists.txt`` to
     )
 
 When you are done developing your pass, you may wish to integrate it
-into LLVM source tree. You can achieve it in two easy steps:
+into the LLVM source tree. You can achieve it in two easy steps:
 
 #. Copying ``<pass name>`` folder into ``<LLVM root>/lib/Transform`` directory.
 
@@ -618,6 +634,6 @@ Microsoft Visual C++
 --------------------
 
 **LLVM_COMPILER_JOBS**:STRING
-  Specifies the maximum number of parallell compiler jobs to use per project
+  Specifies the maximum number of parallel compiler jobs to use per project
   when building with msbuild or Visual Studio. Only supported for the Visual
   Studio 2010 CMake generator. 0 means use all processors. Default is 0.