def METHOD_NAME(tile_segbits, tile_name, tile_bits):
    '''
    Return dict
    key: (address, bit index)
    val: sample description of where it came from (there may be multiple, only one)
    '''
    # FIXME: fix mask files https://github.com/SymbiFlow/prjxray/issues/301
    # in the meantime build them on the fly
    # We may want this to build them anyway
    ret = dict()
    for absaddr, bitaddr, tag in gen_tile_bits(tile_segbits, tile_bits):
        name = "%s.%s" % (tile_name, tag)
        ret.setdefault((absaddr, bitaddr), name)
    return ret