noflatten option does not work for instance count mismatches

[d-m-bailey]

Specifying cells with the -noflatten option should prevent those cells from being flattened.

However, if there is a difference in the cell counts, netgen will flatten cells regardless of whether or not they're tagged noflatten.

Netgen 1.5.227

From the stdout:

Will not flatten these subcells: sky130_fd_sc_hd__decap_12 sky130_fd_sc_hd__decap_3 sky130_fd_sc_hd__decap_4 sky130_fd_sc_hd__decap_6 sky130_fd_sc_hd__decap_8 sky130_fd_sc_hd__diode_2

From the lvs report:

Flattening instances of sky130_fd_sc_hd__diode_2 in cell uP16_efabless (0) makes a better match
Flattening instances of sky130_fd_sc_hd__diode_2 in cell uP16_efabless (1) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_12 in cell uP16_efabless (0) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_12 in cell uP16_efabless (1) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_3 in cell uP16_efabless (0) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_3 in cell uP16_efabless (1) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_4 in cell uP16_efabless (0) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_4 in cell uP16_efabless (1) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_6 in cell uP16_efabless (0) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_6 in cell uP16_efabless (1) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_8 in cell uP16_efabless (0) makes a better match
Flattening instances of sky130_fd_sc_hd__decap_8 in cell uP16_efabless (1) makes a better match

[RTimothyEdwards]

Should be simple enough to fix. . .

[RTimothyEdwards]

Okay, straightforward but not simple. The -noflatten option only works on the script level and has not correspondence in the netgen code. I will need to implement some command line option like flatten <cell> prohibit and build up a list of cells that can be checked against during prematch or after a failed match to prohibit flattening.

[RTimothyEdwards]

Okay, I am implementing what I mentioned above (almost): flatten prohibit <cell> or flatten deny <cell> will mark a cell as a placeholder, which will prevent it from being flattened. The command option will be called for each cell specified by the -noflatten option, although the command can also be put in the setup file (which would render the -noflatten option unnecessary).

I have coded this up but I need to test it because I have questions around the use of the placeholder flag vs. setting the cell class to type "module"; these two are related but I forget the circumstances under which each is used. I'll post an update tomorrow (ping me if I don't).

[RTimothyEdwards]

Fixed in version 1.5.228. -noflatten will now call a new command line option flatten prohibit <cell_name> which then prohibits cells from being flattened at any time during a comparison.

I also discovered another bug in which the -noflatten=<cell_name> syntax does not work (only works with a file name) and fixed that as well.