[libclang] Install both libclang.a and libclang.so when LIBCLANG_BUILD_STATIC=ON

[zhuhan0]

Summary

When LIBCLANG_BUILD_STATIC=ON and LLVM_ENABLE_PIC=ON, PIC version of libclang.a and libclang.so are built as expected. However libclang.a is not installed. Looking at the macro llvm_add_library(), when both SHARED and STATIC are set, it renames the static library to ${name}_static and then adds it to targets. But when add_clang_library() calls install, it only checks if ${name} is in targets.

To work around this issue, loop through both ${name} and ${name}_static and install both of them if they're in targets. This is still correct if only shared or static library is built. In those cases, only ${name} is added to targets and cmake install will generate the right install script depending on the library's type.

Test plan:
cmake with LIBCLANG_BUILD_STATIC=ON and then ninja install, from master and this diff. Compare the result directory trees. Confirm that only difference is the added libclang.a.

[smeenai]

This makes sense to me, but I'd like @beanz and/or @phosek to take a look as well.

[zhuhan0]

Spacing

[zhuhan0]

Rebase

[zhuhan0]

Hello @beanz @phosek @smeenai any comment on this patch? :)

[phosek]

LGTM

[smeenai]

@zhuhan0, do you need someone to commit this for you?

[zhuhan0]

@smeenai Yes.

[smeenai]

Committed. Please forward any buildbot failure emails to me.

[zhuhan0]

@smeenai Thank you!

[hans]

This broke builds configured with -DLLVM_ENABLE_PIC=OFF, e.g.

$ cmake -GNinja -DCMAKE_BUILD_TYPE=Release '-DLLVM_ENABLE_PROJECTS=clang' '-DLLVM_TARGETS_TO_BUILD=X86' -DLLVM_ENABLE_PIC=OFF ../llvm

                                                                           
CMake Error at                                                             
/b/s/w/ir/cache/builder/src/third_party/llvm/clang/tools/libclang/CMakeLists.txt:123
(target_compile_definitions):                                              
    target_compile_definitions called with non-compilable target type

I've reverted in f03b505ee7f23018493b93e3828fc3672c6f903c

[zhuhan0]

Thanks @hans My bad. Didn't test this when LLVM_ENABLE_PIC=OFF.

Submitted D79059 to better solve this problem.

clang/cmake/modules/AddClang.cmake

else()
     if(NOT XCODE)
       # The Xcode generator doesn't handle object libraries correctly.
       list(APPEND LIBTYPE OBJECT)
     endif()
     set_property(GLOBAL APPEND PROPERTY CLANG_STATIC_LIBS ${name})
   endif()
   llvm_add_library(${name} ${LIBTYPE} ${ARG_UNPARSED_ARGUMENTS} ${srcs})
 
-  if(TARGET ${name})
-    target_link_libraries(${name} INTERFACE ${LLVM_COMMON_LIBS})
+  foreach(lib ${name} ${name}_static)
+    if(TARGET ${lib})
+      target_link_libraries(${lib} INTERFACE ${LLVM_COMMON_LIBS})
 
       if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY OR ARG_INSTALL_WITH_TOOLCHAIN)
         set(export_to_clangtargets)
-      if(${name} IN_LIST LLVM_DISTRIBUTION_COMPONENTS OR
+        if(${lib} IN_LIST LLVM_DISTRIBUTION_COMPONENTS OR
             "clang-libraries" IN_LIST LLVM_DISTRIBUTION_COMPONENTS OR
             NOT LLVM_DISTRIBUTION_COMPONENTS)
           set(export_to_clangtargets EXPORT ClangTargets)
           set_property(GLOBAL PROPERTY CLANG_HAS_EXPORTS True)
         endif()
 
-      install(TARGETS ${name}
-        COMPONENT ${name}
+        install(TARGETS ${lib}
+          COMPONENT ${lib}
           ${export_to_clangtargets}
           LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX}
           ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX}
           RUNTIME DESTINATION bin)
 
         if (NOT LLVM_ENABLE_IDE)
-        add_llvm_install_targets(install-${name}
-                                 DEPENDS ${name}
-                                 COMPONENT ${name})
+          add_llvm_install_targets(install-${lib}
+                                  DEPENDS ${lib}
+                                  COMPONENT ${lib})
         endif()
 
-      set_property(GLOBAL APPEND PROPERTY CLANG_LIBS ${name})
+        set_property(GLOBAL APPEND PROPERTY CLANG_LIBS ${lib})
       endif()
-    set_property(GLOBAL APPEND PROPERTY CLANG_EXPORTS ${name})
+      set_property(GLOBAL APPEND PROPERTY CLANG_EXPORTS ${lib})
     else()
       # Add empty "phony" target
-    add_custom_target(${name})
+      add_custom_target(${lib})
     endif()
+  endforeach()
 
   set_target_properties(${name} PROPERTIES FOLDER "Clang libraries")
   set_clang_windows_version_resource_properties(${name})
 endmacro(add_clang_library)
 
 macro(add_clang_executable name)
   add_llvm_executable( ${name} ${ARGN} )
   set_target_properties(${name} PROPERTIES FOLDER "Clang executables")