[llvm] [cmake] Store a list of all possible LLVM_DISTRIBUTION_COMPONENTS

[mgorny]

Summary

Collect all possible LLVM_DISTRIBUTION_COMPONENTS for a given
configuration, and store them in LLVM_ALL_DISTRIBUTION_COMPONENTS cache
variable. This will make it easier for distribution maintainers to
establish the possible options, and to update them on upgrades.

[mgorny]

Actually, this still misses a lot of useful components (such as headers). Help improving it would be welcome.

[beanz]

This isn't really possible to do because CMake doesn't have a mechanism for listing all targets. A more correct approach for this would require generating a ninja build, then you could use ninja -t list to dump all the targets, then you can post-process that list to find a full list of components.

[mgorny]

I suppose I'm looking for all the install-* targets. FWICS I can further filter irrelevant 'metatargets' via looking for install-*-stripped.

[mgorny]

Hmm, that still misses Sphinx docs (HTML + manpages) and opt-viewer.

llvm/CMakeLists.txt

if( ${CMAKE_SYSTEM_NAME} MATCHES SunOS )
    # special hack for Solaris to handle crazy system sys/regset.h
    include_directories("${LLVM_MAIN_INCLUDE_DIR}/llvm/Support/Solaris")
 endif( ${CMAKE_SYSTEM_NAME} MATCHES SunOS )
 
 # Make sure we don't get -rdynamic in every binary. For those that need it,
 # use export_executable_symbols(target).
 set(CMAKE_SHARED_LIBRARY_LINK_CXX_FLAGS "")
 
+set(LLVM_ALL_DISTRIBUTION_COMPONENTS ""
+    CACHE INTERNAL "List of all possible values for LLVM_DISTRIBUTION_COMPONENTS")
+
 include(AddLLVM)
 include(TableGen)
 
 if( MINGW AND NOT "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" )
   # People report that -O3 is unreliable on MinGW. The traditional
   # build also uses -O2 for that reason:
   llvm_replace_compiler_option(CMAKE_CXX_FLAGS_RELEASE "-O3" "-O2")
 endif()

llvm/cmake/modules/AddLLVM.cmake

if (ARG_MODULE AND NOT TARGET ${name})
     # Add empty "phony" target
     add_custom_target(${name})
   elseif( EXCLUDE_FROM_ALL )
     set_target_properties( ${name} PROPERTIES EXCLUDE_FROM_ALL ON)
   elseif(ARG_BUILDTREE_ONLY)
     set_property(GLOBAL APPEND PROPERTY LLVM_EXPORTS_BUILDTREE_ONLY ${name})
   else()
     if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY OR ARG_INSTALL_WITH_TOOLCHAIN)
+      set(LLVM_ALL_DISTRIBUTION_COMPONENTS "${LLVM_ALL_DISTRIBUTION_COMPONENTS};${name}"
+          CACHE INTERNAL "List of all possible values for LLVM_DISTRIBUTION_COMPONENTS")
 
       set(export_to_llvmexports)
       if(${name} IN_LIST LLVM_DISTRIBUTION_COMPONENTS OR
           (in_llvm_libs AND "llvm-libraries" IN_LIST LLVM_DISTRIBUTION_COMPONENTS) OR
           NOT LLVM_DISTRIBUTION_COMPONENTS)
         set(export_to_llvmexports EXPORT LLVMExports)
         set_property(GLOBAL PROPERTY LLVM_HAS_EXPORTS True)
       endif()

 macro(add_llvm_tool name)
   if( NOT LLVM_BUILD_TOOLS )
     set(EXCLUDE_FROM_ALL ON)
   endif()
   add_llvm_executable(${name} ${ARGN})
 
   if ( ${name} IN_LIST LLVM_TOOLCHAIN_TOOLS OR NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
     if( LLVM_BUILD_TOOLS )
+      set(LLVM_ALL_DISTRIBUTION_COMPONENTS "${LLVM_ALL_DISTRIBUTION_COMPONENTS};${name}"
+          CACHE INTERNAL "List of all possible values for LLVM_DISTRIBUTION_COMPONENTS")
+
       set(export_to_llvmexports)
       if(${name} IN_LIST LLVM_DISTRIBUTION_COMPONENTS OR
           NOT LLVM_DISTRIBUTION_COMPONENTS)
         set(export_to_llvmexports EXPORT LLVMExports)
         set_property(GLOBAL PROPERTY LLVM_HAS_EXPORTS True)
       endif()
 
       install(TARGETS ${name}
macro(add_llvm_utility name)
   if ( NOT LLVM_BUILD_UTILS )
     set(EXCLUDE_FROM_ALL ON)
   endif()
 
   add_llvm_executable(${name} DISABLE_LLVM_LINK_LLVM_DYLIB ${ARGN})
   set_target_properties(${name} PROPERTIES FOLDER "Utils")
   if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
     if (LLVM_INSTALL_UTILS AND LLVM_BUILD_UTILS)
+      set(LLVM_ALL_DISTRIBUTION_COMPONENTS "${LLVM_ALL_DISTRIBUTION_COMPONENTS};${name}"
+          CACHE INTERNAL "List of all possible values for LLVM_DISTRIBUTION_COMPONENTS")
+
       set(export_to_llvmexports)
       if (${name} IN_LIST LLVM_DISTRIBUTION_COMPONENTS OR
           NOT LLVM_DISTRIBUTION_COMPONENTS)
         set(export_to_llvmexports EXPORT LLVMExports)
         set_property(GLOBAL PROPERTY LLVM_HAS_EXPORTS True)
       endif()
 
       install(TARGETS ${name}

llvm/cmake/modules/TableGen.cmake

if( ${${project}_TABLEGEN} STREQUAL "${target}" )
       # need to build this tablegen.
       if ( NOT LLVM_BUILD_UTILS )
         set_target_properties(${target} PROPERTIES EXCLUDE_FROM_ALL ON)
       endif()
     endif()
   endif()
 
   if (${project} STREQUAL LLVM AND NOT LLVM_INSTALL_TOOLCHAIN_ONLY AND LLVM_BUILD_UTILS)
+    set(LLVM_ALL_DISTRIBUTION_COMPONENTS "${LLVM_ALL_DISTRIBUTION_COMPONENTS};${target}"
+        CACHE INTERNAL "List of all possible values for LLVM_DISTRIBUTION_COMPONENTS")
+
     set(export_to_llvmexports)
     if(${target} IN_LIST LLVM_DISTRIBUTION_COMPONENTS OR
         NOT LLVM_DISTRIBUTION_COMPONENTS)
       set(export_to_llvmexports EXPORT LLVMExports)
     endif()
 
     install(TARGETS ${target}
             ${export_to_llvmexports}
             RUNTIME DESTINATION ${LLVM_TOOLS_INSTALL_DIR})
   endif()
   set_property(GLOBAL APPEND PROPERTY LLVM_EXPORTS ${target})
 endmacro()

llvm/docs/BuildingADistribution.rst

**LLVM_ENABLE_RUNTIMES**:STRING
   When building a distribution that includes LLVM runtime projects (i.e. libcxx,
   compiler-rt, libcxxabi, libunwind...), it is important to build those projects
   with the just-built compiler.
 
 **LLVM_DISTRIBUTION_COMPONENTS**:STRING
   This variable can be set to a semi-colon separated list of LLVM build system
   components to install. All LLVM-based tools are components, as well as most
   of the libraries and runtimes. Component names match the names of the build
-  system targets.
+  system targets. The list of currently available components (based on enabled
+  options) can be found in *LLVM_ALL_DISTRIBUTION_COMPONENTS* cache variable.
 
 **LLVM_RUNTIME_DISTRIBUTION_COMPONENTS**:STRING
   This variable can be set to a semi-colon separated list of runtime library
   components. This is used in conjunction with *LLVM_ENABLE_RUNTIMES* to specify
   components of runtime libraries that you want to include in your distribution.
   Just like with *LLVM_DISTRIBUTION_COMPONENTS*, component names match the names
   of the build system targets.