fix bugs related to handling of interface libraries

CMake/cotire.cmake

@@ -389,6 +389,24 @@ function (cotire_filter_compile_flags _language _flagFilter _matchedOptionsVar _
 	set (${_unmatchedOptionsVar} ${_unmatchedOptions} PARENT_SCOPE)
 endfunction()
 
+function (cotire_is_target_supported _target _isSupportedVar)
+	if (NOT TARGET "${_target}")
+		set (${_isSupportedVar} FALSE PARENT_SCOPE)
+		return()
+	endif()
+	get_target_property(_imported ${_target} IMPORTED)
+	if (_imported)
+		set (${_isSupportedVar} FALSE PARENT_SCOPE)
+		return()
+	endif()
+	get_target_property(_targetType ${_target} TYPE)
+	if (NOT _targetType MATCHES "EXECUTABLE|(STATIC|SHARED|MODULE|OBJECT)_LIBRARY")
+		set (${_isSupportedVar} FALSE PARENT_SCOPE)
+		return()
+	endif()
+	set (${_isSupportedVar} TRUE PARENT_SCOPE)
+endfunction()
+
 function (cotire_get_target_compile_flags _config _language _target _flagsVar)
 	string (TOUPPER "${_config}" _upperConfig)
 	# collect options from CMake language variables
@@ -3029,10 +3047,16 @@ function (cotire_target _target)
 	if (NOT _option_CONFIGURATIONS)
 		cotire_get_configuration_types(_option_CONFIGURATIONS)
 	endif()
-	# trivial checks
-	get_target_property(_imported ${_target} IMPORTED)
-	if (_imported)
-		message (WARNING "cotire: imported target ${_target} cannot be cotired.")
+	# check if cotire can be applied to target at all
+	cotire_is_target_supported(${_target} _isSupported)
+	if (NOT _isSupported)
+		get_target_property(_imported ${_target} IMPORTED)
+		get_target_property(_targetType ${_target} TYPE)
+		if (_imported)
+			message (WARNING "cotire: imported ${_targetType} target ${_target} cannot be cotired.")
+		else()
+			message (STATUS "cotire: ${_targetType} target ${_target} cannot be cotired.")
+		endif()
 		return()
 	endif()
 	# resolve alias
@@ -3097,11 +3121,16 @@ endfunction(cotire_target)
 function (cotire_map_libraries _strategy _mappedLibrariesVar)
 	set (_mappedLibraries "")
 	foreach (_library ${ARGN})
-		if (TARGET "${_library}" AND "${_strategy}" MATCHES "COPY_UNITY")
-			# use target's corresponding unity target, if available
-			get_target_property(_libraryUnityTargetName ${_library} COTIRE_UNITY_TARGET_NAME)
-			if (TARGET "${_libraryUnityTargetName}")
-				list (APPEND _mappedLibraries "${_libraryUnityTargetName}")
+		if ("${_strategy}" MATCHES "COPY_UNITY")
+			cotire_is_target_supported(${_library} _isSupported)
+			if (_isSupported)
+				# use target's corresponding unity target, if available
+				get_target_property(_libraryUnityTargetName ${_library} COTIRE_UNITY_TARGET_NAME)
+				if (TARGET "${_libraryUnityTargetName}")
+					list (APPEND _mappedLibraries "${_libraryUnityTargetName}")
+				else()
+					list (APPEND _mappedLibraries "${_library}")
+				endif()
 			else()
 				list (APPEND _mappedLibraries "${_library}")
 			endif()
@@ -3114,6 +3143,10 @@ function (cotire_map_libraries _strategy _mappedLibrariesVar)
 endfunction()
 
 function (cotire_target_link_libraries _target)
+	cotire_is_target_supported(${_target} _isSupported)
+	if (NOT _isSupported)
+		return()
+	endif()
 	get_target_property(_unityTargetName ${_target} COTIRE_UNITY_TARGET_NAME)
 	if (TARGET "${_unityTargetName}")
 		get_target_property(_linkLibrariesStrategy ${_target} COTIRE_UNITY_LINK_LIBRARIES_INIT)