abc9: uniquify blackboxes like whiteboxes (#2695)

* abc9_ops: uniquify blackboxes too

* abc9_ops: update comment

* abc9_ops: allow bypass for param-less blackboxes

* Add tests

1 files changed, 6 insertions, 10 deletions

diff --git a/passes/techmap/abc9_ops.cc b/passes/techmap/abc9_ops.cc
index d3bb31cd9..6e18cb5f6 100644
--- a/passes/techmap/abc9_ops.cc
+++ b/passes/techmap/abc9_ops.cc
@@ -189,8 +189,6 @@ void prep_hier(RTLIL::Design *design, bool dff_mode)
 				derived_type = inst_module->derive(design, cell->parameters);
 				derived_module = design->module(derived_type);
 			}
-			if (derived_module->get_blackbox_attribute(true /* ignore_wb */))
-				continue;
 
 			if (derived_module->get_bool_attribute(ID::abc9_flop)) {
 				if (!dff_mode)
@@ -799,14 +797,12 @@ void prep_xaiger(RTLIL::Module *module, bool dff)
 		if (!box_module->get_bool_attribute(ID::abc9_box))
 			continue;
 		if (!cell->parameters.empty())
-			// At this stage of the ABC9 flow, all modules must be nonparametric, because ABC itself requires concrete netlists, and the presence of
-			// parameters implies a non-concrete netlist. This error needs some explaining, because there are (at least) two ways to get this:
-			// 1) You have an (* abc9_box *) parametric whitebox but due to a bug somewhere this hasn't been monomorphised into a concrete blackbox.
-			//    This is a bug, and a bug report would be welcomed.
-			// 2) You have an (* abc9_box *) parametric blackbox (e.g. to store associated cell data) but want to provide timing data for ABC9.
-			//    This is not supported due to the presence of parameters. If you want to store associated cell data for a box, one approach could be
-			//    to techmap the parameters to constant module inputs, and then after ABC9 use _TECHMAP_CONSTVAL_XX_ to retrieve the values again.
-			log_error("Black box '%s' is marked (* abc9_box *) and has parameters, which is forbidden in prep_xaiger\n", log_id(cell_name));
+		{
+		    // At this stage of the ABC9 flow, all modules must be nonparametric, because ABC itself requires concrete netlists, and the presence of
+		    // parameters implies a non-concrete netlist. This means an (* abc9_box *) parametric module but due to a bug somewhere this hasn't been
+		    // uniquified into a concrete parameter-free module. This is a bug, and a bug report would be welcomed.
+		    log_error("Not expecting parameters on module '%s'  marked (* abc9_box *)\n", log_id(cell_name));
+		}
 		log_assert(box_module->get_blackbox_attribute());
 
 		cell->attributes[ID::abc9_box_seq] = box_count++;