[cmake] Remove LLVM_{BUILD,LINK}_LLVM_DYLIB options on Windows

[tstellar]

Summary

The options aren't supported so they can be removed.

llvm/CMakeLists.txt

 
 # You can configure which libraries from LLVM you want to include in the
 # shared library by setting LLVM_DYLIB_COMPONENTS to a semi-colon delimited
 # list of LLVM components. All component names handled by llvm-config are valid.
 if(NOT DEFINED LLVM_DYLIB_COMPONENTS)
   set(LLVM_DYLIB_COMPONENTS "all" CACHE STRING
     "Semicolon-separated list of components to include in libLLVM, or \"all\".")
 endif()
-option(LLVM_LINK_LLVM_DYLIB "Link tools against the libllvm dynamic library" OFF)
+
 if(MSVC)
   option(LLVM_BUILD_LLVM_C_DYLIB "Build LLVM-C.dll (Windows only)" ON)
+  # Set this variable to OFF here so it can't be set with a command-line
+  # argument.
+  set (LLVM_LINK_LLVM_DYLIB OFF)
 else()
+  option(LLVM_LINK_LLVM_DYLIB "Link tools against the libllvm dynamic library" OFF)
   option(LLVM_BUILD_LLVM_C_DYLIB "Build libllvm-c re-export library (Darwin only)" OFF)
-endif()
   set(LLVM_BUILD_LLVM_DYLIB_default OFF)
-if(LLVM_LINK_LLVM_DYLIB OR (LLVM_BUILD_LLVM_C_DYLIB AND NOT MSVC))
+  if(LLVM_LINK_LLVM_DYLIB OR LLVM_BUILD_LLVM_C_DYLIB)
     set(LLVM_BUILD_LLVM_DYLIB_default ON)
   endif()
   option(LLVM_BUILD_LLVM_DYLIB "Build libllvm dynamic library" ${LLVM_BUILD_LLVM_DYLIB_default})
+endif()
 
 option(LLVM_OPTIMIZED_TABLEGEN "Force TableGen to be built with optimization" OFF)
 if(CMAKE_CROSSCOMPILING OR (LLVM_OPTIMIZED_TABLEGEN AND (LLVM_ENABLE_ASSERTIONS OR CMAKE_CONFIGURATION_TYPES)))
   set(LLVM_USE_HOST_TOOLS ON)
 endif()
 
 if (MSVC_IDE)
   option(LLVM_ADD_NATIVE_VISUALIZERS_TO_SOLUTION "Configure project to use Visual Studio native visualizers" TRUE)

llvm/docs/BuildingADistribution.rst

 --------------------------------------------
 
 One of the most powerful features of LLVM is its library-first design mentality
 and the way you can compose a wide variety of tools using different portions of
 LLVM. Even in this situation using *BUILD_SHARED_LIBS* is not supported. If you
 want to distribute LLVM as a shared library for use in a tool, the recommended
 method is using *LLVM_BUILD_LLVM_DYLIB*, and you can use *LLVM_DYLIB_COMPONENTS*
 to configure which LLVM components are part of libLLVM.
+Note: *LLVM_BUILD_LLVM_DYLIB* is not available on Windows.
 
 Options for Optimizing LLVM
 ===========================
 
 There are four main build optimizations that our CMake build system supports.
 When performing a bootstrap build it is not beneficial to do anything other than
 setting *CMAKE_BUILD_TYPE* to ``Release`` for the stage-1 compiler. This is
 because the more intensive optimizations are expensive to perform and the

llvm/docs/CMake.rst

 **LLVM_BUILD_LLVM_DYLIB**:BOOL
   If enabled, the target for building the libLLVM shared library is added.
   This library contains all of LLVM's components in a single shared library.
   Defaults to OFF. This cannot be used in conjunction with BUILD_SHARED_LIBS.
   Tools will only be linked to the libLLVM shared library if LLVM_LINK_LLVM_DYLIB
   is also ON.
   The components in the library can be customised by setting LLVM_DYLIB_COMPONENTS
   to a list of the desired components.
+  This option is not available on Windows.
 
 **LLVM_LINK_LLVM_DYLIB**:BOOL
   If enabled, tools will be linked with the libLLVM shared library. Defaults
   to OFF. Setting LLVM_LINK_LLVM_DYLIB to ON also sets LLVM_BUILD_LLVM_DYLIB
   to ON.
+  This option is not available on Windows.
 
 **BUILD_SHARED_LIBS**:BOOL
   Flag indicating if each LLVM component (e.g. Support) is built as a shared
   library (ON) or as a static library (OFF). Its default value is OFF. On
   Windows, shared libraries may be used when building with MinGW, including
   mingw-w64, but not when building with the Microsoft toolchain.
 
   .. note:: BUILD_SHARED_LIBS is only recommended for use by LLVM developers.

llvm/docs/GettingStarted.rst

 |                         | code. This is disabled by default because it is    |
 |                         | slow and generates a lot of output. Sphinx version |
 |                         | 1.5 or later recommended.                          |
 +-------------------------+----------------------------------------------------+
 | LLVM_BUILD_LLVM_DYLIB   | Generate libLLVM.so. This library contains a       |
 |                         | default set of LLVM components that can be         |
 |                         | overridden with ``LLVM_DYLIB_COMPONENTS``. The     |
 |                         | default contains most of LLVM and is defined in    |
-|                         | ``tools/llvm-shlib/CMakelists.txt``.               |
+|                         | ``tools/llvm-shlib/CMakelists.txt``. This option is|
+|                         | not avialable on Windows.                          |
 +-------------------------+----------------------------------------------------+
 | LLVM_OPTIMIZED_TABLEGEN | Builds a release tablegen that gets used during    |
 |                         | the LLVM build. This can dramatically speed up     |
 |                         | debug builds.                                      |
 +-------------------------+----------------------------------------------------+
 
 To configure LLVM, follow these steps:
 

llvm/docs/ReleaseNotes.rst

* Enabled MemorySSA as a loop dependency. Since
   with a small number of overall memory instructions. This choice was motivated
   by experimental results showing compile and run time benefits or replacing the
   AliasSetTracker usage with MemorySSA without any performance penalties.
   The fact that MemorySSA is now preserved by and available in a series of loop
   passes, also opens up opportunities for its use in those respective passes.
 * The BasicBlockPass, BBPassManager and all their uses were deleted in
   `this revision <https://reviews.llvm.org/rG9f0ff0b2634bab6a5be8dace005c9eb24d386dd1>`_.
 
+* The LLVM_BUILD_LLVM_DYLIB and LLVM_LINK_LLVM_DYLIB CMake options are no longer
+  available on Windows.
+
 .. NOTE
    If you would like to document a larger change, then you can add a
    subsection about it right here. You can copy the following boilerplate
    and un-indent it (the indentation causes it to be inside this comment).
 
    Special New Feature
    -------------------