lldb: repair the standalone build for Windows

[compnerd]

Summary

The previous code path only happened to work incidentally. The
file(MAKE_DIRECTORY) is executed early, without the generator
expression being evaluated. The result is that the literal value is
being treated as a path. However, on Windows : is not a valid
character for a file name. This would cause the operation to fail. The
subsequent commands are delayed until runtime, and the operations will
expand the value at generation time yielding the correct result.

[JDevlieghere]

LGTM but I'd like @teemperor to have a look too as he authored the original change.

[teemperor]

(I'm very sorry for the delay, that slipped out of my review queue.)

Wouldn't changing this logic to an explicit get_target_property call break the multi-config projects (where there are multiple possible paths)?

I actually think the easiest solution is to just delete the file(MAKE_DIRECTORY ... line. As you described it's not doing what it should and as we create the directory in the custom command below it is redundant. I believe this line is only a remnant from when I tried to get this working in non-multi-config generator setups.

lldb/source/API/CMakeLists.txt

 else()
   # In a standalone build create a symlink from the LLDB library directory that points to the
   # resource directory in the Clang library directory. LLDB searches relative to its install path,
   # and the symlink is created in the same relative path as the resource directory of Clang when
   # building alongside Clang.
   # When building the LLDB framework, this isn't necessary as there we copy everything we need into
   # the framework (including the Clang resourece directory).
   if(NOT LLDB_BUILD_FRAMEWORK)
-    set(LLDB_CLANG_RESOURCE_DIR_PARENT "$<TARGET_FILE_DIR:liblldb>/clang")
-    file(MAKE_DIRECTORY "${LLDB_CLANG_RESOURCE_DIR_PARENT}")
+    get_target_property(liblldb_TARGET_FILE_DIR liblldb TARGET_FILE_DIR)
+    file(MAKE_DIRECTORY "${liblldb_TARGET_FILE_DIR}/clang")
     add_custom_command(TARGET liblldb POST_BUILD
-      COMMENT "Linking Clang resource dir into LLDB build directory: ${LLDB_CLANG_RESOURCE_DIR_PARENT}"
-      COMMAND ${CMAKE_COMMAND} -E make_directory "${LLDB_CLANG_RESOURCE_DIR_PARENT}"
-      COMMAND ${CMAKE_COMMAND} -E create_symlink "${LLDB_EXTERNAL_CLANG_RESOURCE_DIR}"
-              "${LLDB_CLANG_RESOURCE_DIR_PARENT}/${LLDB_CLANG_RESOURCE_DIR_NAME}"
+      COMMENT "Linking Clang resource dir into LLDB build directory: ${liblldb_TARGET_FILE_DIR}/clang"
+      COMMAND ${CMAKE_COMMAND} -E make_directory "${liblldb_TARGET_FILE_DIR}/clang"
+      COMMAND ${CMAKE_COMMAND} -E create_symlink "${LLDB_EXTERNAL_CLANG_RESOURCE_DIR}" "${liblldb_TARGET_FILE_DIR}/clang/${LLDB_CLANG_RESOURCE_DIR_NAME}"
     )
   endif()
 endif()
 
 if(LLDB_BUILD_FRAMEWORK)
   include(LLDBFramework)
 endif()