private DataType findBaseDataType(String dataTypeName, TaskMonitor monitor)
			throws CancelledException {
		DataType dt = getCachedDataType(dataTypeName);
		if (dt != null) {
			return dt;
		}

		// PDP category does not apply to built-ins which always live at the root

		BuiltInDataTypeManager builtInDTM = BuiltInDataTypeManager.getDataTypeManager();
		dt = builtInDTM.getDataType(new DataTypePath(CategoryPath.ROOT, dataTypeName));
		if (dt == null) {
			dt = findDataTypeInArchives(dataTypeName, monitor);
		}
		return dt;
	}
Ensures that the data type managers are used in a particular order.
The order is as follows:
   1) the program's data type manager
   2) the built-in data type manager
   3) the open data type archives
Ghidra/Features/PDB/src/main/java/ghidra/app/util/bin/format/pdb/PdbDataTypeParser.java