在design中含有模拟模块的时候，特别是自研的模拟IP可能是没有lef的
这种时候就没有办法通过lef转NDM
此时可以通过GDS转NDM
TCL COMMON：
set tf xxx.tf
set mapfile XXX.map
set all_gds "[XXX.gds]"
foreach gds $all_gds {
set gds_file [file tail $gds]
regexp {(.*).gds} $gds_file matchvar cell_name
create_workspace $cell_name -technology $tf -flow normal
read_gds -verbose -trace_option auto -latyer_map $mapfile $gds
current_block *:$cell_name
set_att [get_lib_cells */$cell_name] boundary {{X X} {X X}}
set_att [get_lib_cells */$cell_name] design_type pad
check_workspace
commit_workspace
}