Merge pull request #7486 from hughbe/precondition-addswift-cleanup

Cleanup CMake _require_empty list

Author: hughbe

cmake/modules/AddSwift.cmake

@@ -27,12 +27,6 @@ function(add_dependencies_multiple_targets)
   endif()
 endfunction()
 
-function(_require_empty_list the_list the_message)
-  if(the_list)
-    message(FATAL_ERROR "${the_message}")
-  endif()
-endfunction()
-
 # Compute the library subdirectory to use for the given sdk and
 # architecture, placing the result in 'result_var_name'.
 function(compute_library_subdir result_var_name sdk arch)
@@ -976,7 +970,7 @@ function(_add_swift_library_single target name)
   if("${libkind}" STREQUAL "SHARED")
     target_link_libraries("${target}" PRIVATE ${SWIFTLIB_SINGLE_LINK_LIBRARIES})
   elseif("${libkind}" STREQUAL "OBJECT")
-    _require_empty_list(
+    precondition_list_empty(
         "${SWIFTLIB_SINGLE_LINK_LIBRARIES}"
         "OBJECT_LIBRARY may not link to anything")
   else()
@@ -1153,15 +1147,15 @@ function(_add_swift_library_single target name)
   endif()
 
   if("${libkind}" STREQUAL "OBJECT")
-    _require_empty_list(
+    precondition_list_empty(
         "${SWIFTLIB_SINGLE_PRIVATE_LINK_LIBRARIES}"
         "OBJECT_LIBRARY may not link to anything")
   else()
     target_link_libraries("${target}" PRIVATE
         ${SWIFTLIB_SINGLE_PRIVATE_LINK_LIBRARIES})
   endif()
   if("${libkind}" STREQUAL "OBJECT")
-    _require_empty_list(
+    precondition_list_empty(
         "${SWIFTLIB_SINGLE_INTERFACE_LINK_LIBRARIES}"
         "OBJECT_LIBRARY may not link to anything")
   else()

cmake/modules/SwiftList.cmake

@@ -91,3 +91,7 @@ function(precondition_list_is_disjoint first)
     list_union(RESULT "${${l}}" "${RESULT}")
   endforeach()
 endfunction()
+
+function(precondition_list_empty l message)
+  precondition(l NEGATE MESSAGE "${message}")
+endfunction()