[CMake] Support exporting runtimes using the CMake export

[phosek]

Summary

We collect target names in the global LLVM_RUNTIMES property and
then export them to a per-target export file.

[smeenai]

libcxx/lib/CMakeLists.txt

101 ↗

(On Diff #185694)

Seems like an unrelated change? I can see how it was exposed by adding the exported target support, but it still seems like it could go in separately.

llvm/runtimes/CMakeLists.txt

215

Why do we need to collect targets manually instead of just using the export(EXPORT) signature?

218

Is this assuming the per-triple resource directory layout?

[phosek]

libcxx/lib/CMakeLists.txt

101 ↗

(On Diff #185694)

D57872 is the right way which is the dependency of this change, once it lands I'll rebase this.

llvm/runtimes/CMakeLists.txt

215

I just followed what LLVM already does for LLVMExports but I'm fine using export(EXPORT) if that's preferred.

218

Yes, that's already used for the runtimes build: https://github.com/llvm/llvm-project/blob/master/llvm/runtimes/CMakeLists.txt#L345

[smeenai]

llvm/runtimes/CMakeLists.txt

215

Yeah, the export(EXPORT) form should be equivalent here I think, and it should eliminate redundancies/prevent future divergences, so I'd prefer that.

[phosek]

Ping?

[smeenai]

Sorry, had missed this.

I realized later that LLVM's export setup is to support selectively exporting components using LLVM_DISTRIBUTION_COMPONENTS. Is there an equivalent to that in the runtimes world? If there is, the export installation should respect that; if not, this LGTM.

[ldionne]

Sorry, I did not see previous revisions of this, but this looks unrelated to CMake at all now -- am I mistaken? The only CMake change is re-indenting unless I missed something.

[smeenai]

Seems like you got the wrong diff.

[phosek]

In D49587#1488328, @smeenai wrote:

Seems like you got the wrong diff.

It was the right diff but uploaded to a wrong change ;)

In D49587#1484829, @smeenai wrote:

Sorry, had missed this.

I realized later that LLVM's export setup is to support selectively exporting components using LLVM_DISTRIBUTION_COMPONENTS. Is there an equivalent to that in the runtimes world? If there is, the export installation should respect that; if not, this LGTM.

There's LLVM_RUNTIME_DISTRIBUTION_COMPONENTS which @beanz introduced a while back which is supposed to serve the same purpose. I wired it up but there were some other issues that were revealed while testing this change, hopefully those should be all addressed now.

[smeenai]

libunwind/src/CMakeLists.txt

160

Should be libunwind and not libcxxabi

llvm/runtimes/CMakeLists.txt

216

I think the way LLVM's build is set up, targets are always exported to the export file in the build tree (which requires maintaining the separate list of targets), but only exported to the install tree if they're in LLVM_DISTRIBUTION_COMPONENTS. I don't know how much you care about maintaining that behavior here.

[ldionne]

I think the right way to do this was to use install(export)?

[ldionne]

In D49587#1493585, @ldionne wrote:

I think the right way to do this was to use install(export)?

Oh, and you are doing this, but in llvm/runtimes. Why don't we handle this per project? I don't think we should assume that the rest of LLVM is available in order to export those targets.

[smeenai]

Clearing my queue.

clang/cmake/caches/Fuchsia-stage2.cmake

set(LLVM_DISTRIBUTION_COMPONENTS
   clang-include-fixer
   clang-refactor
   clang-tidy
   clangd
   builtins
   runtimes
   ${LLVM_TOOLCHAIN_TOOLS}
   CACHE STRING "")
+
+set(LLVM_RUNTIME_DISTRIBUTION_COMPONENTS
+  compiler-rt
+  libcxx
+  libcxxabi
+  libunwind
+  CACHE STRING "")

compiler-rt/cmake/Modules/AddCompilerRT.cmake

if(type STREQUAL "OBJECT")
         ${COMPONENT_OPTION})
     else()
       add_library(${libname} ${type} ${sources_${libname}})
       set_target_compile_flags(${libname} ${extra_cflags_${libname}})
       set_target_link_flags(${libname} ${extra_link_flags_${libname}})
       set_property(TARGET ${libname} APPEND PROPERTY
                    COMPILE_DEFINITIONS ${LIB_DEFS})
       set_target_output_directories(${libname} ${output_dir_${libname}})
-      install(TARGETS ${libname}
+      if(${name} IN_LIST LLVM_RUNTIME_DISTRIBUTION_COMPONENTS OR
+         "compiler-rt" IN_LIST LLVM_RUNTIME_DISTRIBUTION_COMPONENTS)
+        set(export_to_llvmruntimes EXPORT LLVMRuntimes)
+        set_property(GLOBAL PROPERTY LLVM_RUNTIME_HAS_EXPORTS TRUE)
+      endif()
+      install(TARGETS ${libname} ${export_to_llvmruntimes}
         ARCHIVE DESTINATION ${install_dir_${libname}}
                 ${COMPONENT_OPTION}
         LIBRARY DESTINATION ${install_dir_${libname}}
                 ${COMPONENT_OPTION}
         RUNTIME DESTINATION ${install_dir_${libname}}
                 ${COMPONENT_OPTION})
     endif()
     set_target_properties(${libname} PROPERTIES

libcxx/src/CMakeLists.txt

PROPERTIES
       OUTPUT_NAME   "c++external_threads"
   )
 endif()
 
 if (LIBCXX_INSTALL_LIBRARY)
   if (LIBCXX_INSTALL_EXPERIMENTAL_LIBRARY)
     set(experimental_lib cxx_experimental)
   endif()
-  install(TARGETS ${LIBCXX_INSTALL_TARGETS} ${experimental_lib}
+  if(libcxx IN_LIST LLVM_RUNTIME_DISTRIBUTION_COMPONENTS)
+    set(export_to_llvmruntimes EXPORT LLVMRuntimes)
+    set_property(GLOBAL PROPERTY LLVM_RUNTIME_HAS_EXPORTS TRUE)
+  endif()
+  install(TARGETS ${LIBCXX_INSTALL_TARGETS} ${experimental_lib} ${export_to_llvmruntimes}
     LIBRARY DESTINATION ${LIBCXX_INSTALL_PREFIX}lib${LIBCXX_LIBDIR_SUFFIX} COMPONENT cxx
     ARCHIVE DESTINATION ${LIBCXX_INSTALL_PREFIX}lib${LIBCXX_LIBDIR_SUFFIX} COMPONENT cxx
     )
   # NOTE: This install command must go after the cxx install command otherwise
   # it will not be executed after the library symlinks are installed.
   if (LIBCXX_ENABLE_SHARED AND LIBCXX_ENABLE_ABI_LINKER_SCRIPT)
     # Replace the libc++ filename with $<TARGET_LINKER_FILE:cxx>
     # after we required CMake 3.0.

libcxxabi/src/CMakeLists.txt

if(LIBCXXABI_USE_LLVM_UNWINDER AND LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY)
     )
   endif()
 endif()
 
 # Add a meta-target for both libraries.
 add_custom_target(cxxabi DEPENDS ${LIBCXXABI_BUILD_TARGETS})
 
 if (LIBCXXABI_INSTALL_LIBRARY)
-  install(TARGETS ${LIBCXXABI_INSTALL_TARGETS}
+  if(libcxxabi IN_LIST LLVM_RUNTIME_DISTRIBUTION_COMPONENTS)
+    set(export_to_llvmruntimes EXPORT LLVMRuntimes)
+    set_property(GLOBAL PROPERTY LLVM_RUNTIME_HAS_EXPORTS TRUE)
+  endif()
+  install(TARGETS ${LIBCXXABI_INSTALL_TARGETS} ${export_to_llvmruntimes}
     LIBRARY DESTINATION ${LIBCXXABI_INSTALL_PREFIX}lib${LIBCXXABI_LIBDIR_SUFFIX} COMPONENT cxxabi
     ARCHIVE DESTINATION ${LIBCXXABI_INSTALL_PREFIX}lib${LIBCXXABI_LIBDIR_SUFFIX} COMPONENT cxxabi
     )
 endif()
 
 if (NOT CMAKE_CONFIGURATION_TYPES AND LIBCXXABI_INSTALL_LIBRARY)
   add_custom_target(install-cxxabi
     DEPENDS cxxabi

libunwind/src/CMakeLists.txt

if (LIBUNWIND_INSTALL_STATIC_LIBRARY)
     list(APPEND LIBUNWIND_INSTALL_TARGETS "unwind_static")
   endif()
 endif()
 
 # Add a meta-target for both libraries.
 add_custom_target(unwind DEPENDS ${LIBUNWIND_BUILD_TARGETS})
 
 if (LIBUNWIND_INSTALL_LIBRARY)
-  install(TARGETS ${LIBUNWIND_INSTALL_TARGETS}
+  if(libcxxabi IN_LIST LLVM_RUNTIME_DISTRIBUTION_COMPONENTS)
+    set(export_to_llvmruntimes EXPORT LLVMRuntimes)
+    set_property(GLOBAL PROPERTY LLVM_RUNTIME_HAS_EXPORTS TRUE)
+  endif()
+  install(TARGETS ${LIBUNWIND_INSTALL_TARGETS} ${export_to_llvmruntimes}
     LIBRARY DESTINATION ${LIBUNWIND_INSTALL_PREFIX}lib${LIBUNWIND_LIBDIR_SUFFIX} COMPONENT unwind
     ARCHIVE DESTINATION ${LIBUNWIND_INSTALL_PREFIX}lib${LIBUNWIND_LIBDIR_SUFFIX} COMPONENT unwind)
 endif()
 
 if (NOT CMAKE_CONFIGURATION_TYPES AND LIBUNWIND_INSTALL_LIBRARY)
   add_custom_target(install-unwind
     DEPENDS unwind
     COMMAND "${CMAKE_COMMAND}"

llvm/runtimes/CMakeLists.txt

if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
   # Handle common options used by all runtimes.
   include(AddLLVM)
   include(HandleLLVMOptions)
   include(FindPythonInterp)
 
   # Remove the -nostdlib++ option we've added earlier.
   string(REPLACE "-nostdlib++" "" CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
 
+  string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION
+         ${PACKAGE_VERSION})
+
   # This can be used to detect whether we're in the runtimes build.
   set(RUNTIMES_BUILD ON)
 
   foreach(entry ${runtimes})
     get_filename_component(projName ${entry} NAME)
 
     # TODO: Clean this up as part of an interface standardization
     string(REPLACE "-" "_" canon_name ${projName})
if(LLVM_RUNTIMES_TARGET)
         ${LLVM_BINARY_DIR}/runtimes/${LLVM_RUNTIMES_TARGET}/Components.cmake)
     else()
       configure_file(
         ${CMAKE_CURRENT_SOURCE_DIR}/Components.cmake.in
         ${LLVM_BINARY_DIR}/runtimes/Components.cmake)
     endif()
   endif()
 
+  get_property(llvm_runtime_has_exports GLOBAL PROPERTY LLVM_RUNTIME_HAS_EXPORTS)
+  if(llvm_runtime_has_exports)
+    if(LLVM_RUNTIMES_TARGET)
+      set(LLVM_RUNTIMES_FILE ${LLVM_BINARY_DIR}/runtimes/${LLVM_RUNTIMES_TARGET}/LLVMRuntimes.cmake)
+    else()
+      set(LLVM_RUNTIMES_FILE ${LLVM_BINARY_DIR}/runtimes/LLVMRuntimes.cmake)
+    endif()
+    export(EXPORT LLVMRuntimes FILE ${LLVM_RUNTIMES_FILE})
+    install(EXPORT LLVMRuntimes
+            DESTINATION lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}
+            COMPONENT cmake-exports)
+  endif()
 else() # if this is included from LLVM's CMake
   include(LLVMExternalProjectUtils)
 
   if(NOT LLVM_BUILD_RUNTIMES)
     set(EXTRA_ARGS EXCLUDE_FROM_ALL)
   endif()
 
   function(builtin_default_target compiler_rt_path)
function(runtime_register_target name target)
     foreach(target_name IN LISTS SUB_COMPONENTS SUB_INSTALL_TARGETS)
       set(${target_name}-${name} ${target_name})
       list(APPEND ${name}_extra_targets ${target_name}-${name})
     endforeach()
 
     foreach(component ${LLVM_RUNTIME_DISTRIBUTION_COMPONENTS})
       set(${component}-${name} ${component})
       set(install-${component}-${name} ${component})
-      list(APPEND ${name}_extra_targets ${component}-${name} install-${component}-${name})
+      set(install-${component}-${name}-stripped ${component})
+      if(NOT ${component}-${name} IN_LIST extra_targets)
+        list(APPEND ${extra}_extra_targets ${component}-${name} install-${component}-${name} install-${component}-${name}-stripped)
+      endif()
     endforeach()
 
     if(LLVM_INCLUDE_TESTS)
       set(runtimes-test-depends-${name} runtimes-test-depends)
       set(check-runtimes-${name} check-runtimes)
       list(APPEND ${name}_test_targets runtimes-test-depends-${name} check-runtimes-${name})
       foreach(target_name IN LISTS SUB_CHECK_TARGETS)
         set(${target_name}-${name} ${target_name})
llvm_ExternalProject_Add(runtimes-${name}
                                         -DCMAKE_ASM_COMPILER_TARGET=${target}
                                         -DCMAKE_C_COMPILER_WORKS=ON
                                         -DCMAKE_CXX_COMPILER_WORKS=ON
                                         -DCMAKE_ASM_COMPILER_WORKS=ON
                                         -DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
                                         -DLLVM_RUNTIMES_TARGET=${name}
                                         ${${name}_extra_args}
                              PASSTHROUGH_PREFIXES LLVM_ENABLE_RUNTIMES
+                                                  LLVM_RUNTIME_DISTRIBUTION_COMPONENTS
                              TOOLCHAIN_TOOLS clang lld llvm-ar llvm-ranlib llvm-nm llvm-objcopy llvm-objdump llvm-strip
                              EXTRA_TARGETS ${${name}_extra_targets}
                                            ${${name}_test_targets}
                              USE_TOOLCHAIN
                              ${EXTRA_ARGS})
   endfunction()
 
   if(runtimes)
else()
           add_custom_target(check-runtimes)
           add_custom_target(runtimes-test-depends)
           set(test_targets "")
         endif()
         if(LLVM_RUNTIME_DISTRIBUTION_COMPONENTS)
           foreach(component ${LLVM_RUNTIME_DISTRIBUTION_COMPONENTS})
             add_custom_target(${component})
             add_custom_target(install-${component})
+            add_custom_target(install-${component}-stripped)
           endforeach()
         endif()
       endif()
 
       foreach(name ${LLVM_RUNTIME_TARGETS})
         runtime_register_target(${name} ${name}
           DEPENDS ${deps})