Best practices when adding a POST <STEP> TCL file which changes the DB

[chrisgelinek-rl]

I have a post_fill_repair.tcl script which calls load_design 6_1_fill.odb 6_1_fill.sdc and then calls detailed_route to fix any DRC violations created by the filler insertion (I allowed it to use filler cap cells as well as "empty" fillers). I think the right way to include it in the flow is to simply export POST_DENSITY_FILL_TCL = post_fill_repair.tcl and it should automatically run after density_fill.

This works great, but since density_fill.tcl runs orfs_write_db $::env(RESULTS_DIR)/6_1_fill.odb before calling source_step_tcl POST DENSITY_FILL, the in-memory database changes will not be saved by density_fill.tcl.

I could save the database under a new name - I thought I'd use something like orfs_write_db $::env(RESULTS_DIR)/6_2_post_fill_repair.odb - but this would then be ignored by the next step (final_report.tcl which loads hard-coded 6_1_fill.odb).

This suggests I should overwrite 6_1_fill.odb and 6_1_fill.sdc, but then I'd lose the state from before the post_fill_repair.tcl script ran.

This could be solved by renaming all 6_1_fill* files at the beginning of post_fill_repair.tcl (to e.g. 6_1_unrepaired_fill*) and then write 6_1_fill.odb and 6_1_fill.sdc at the end, but this seems quite brittle as well (the reports and logs should probably also be renamed to match which starts to get confusing).

What's the best approach when one wants to insert some DB manipulation into the standard flow?

Note that other steps (at least detail_route.tcl) seem to write the DB file after running any POST TCL script, so the approach may need to be different depending on the step...