1 files changed, 190 insertions, 244 deletions

diff --git a/passes/techmap/abc9.cc b/passes/techmap/abc9.cc
index d03e5da8e..19a1d2ccb 100644
--- a/passes/techmap/abc9.cc
+++ b/passes/techmap/abc9.cc
@@ -65,20 +65,15 @@ PRIVATE_NAMESPACE_BEGIN
 
 bool markgroups;
 int map_autoidx;
-SigMap assign_map;
-RTLIL::Module *module;
-
-bool clk_polarity, en_polarity;
-RTLIL::SigSpec clk_sig, en_sig;
 
 inline std::string remap_name(RTLIL::IdString abc9_name)
 {
 	return stringf("$abc$%d$%s", map_autoidx, abc9_name.c_str()+1);
 }
 
-void handle_loops(RTLIL::Design *design)
+void handle_loops(RTLIL::Design *design, RTLIL::Module *module)
 {
-	Pass::call(design, "scc -set_attr abc9_scc_id {}");
+	Pass::call(design, "scc -set_attr abc9_scc_id {} % w:*");
 
 	// For every unique SCC found, (arbitrarily) find the first
 	// cell in the component, and select (and mark) all its output
@@ -253,49 +248,14 @@ struct abc9_output_filter
 	}
 };
 
-void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::string script_file, std::string exe_file,
-		bool cleanup, vector<int> lut_costs, bool dff_mode, std::string clk_str,
-		bool /*keepff*/, std::string delay_target, std::string /*lutin_shared*/, bool fast_mode,
-		bool show_tempdir, std::string box_file, std::string lut_file,
+void abc9_module(RTLIL::Design *design, RTLIL::Module *module, std::string script_file, std::string exe_file,
+		bool cleanup, vector<int> lut_costs, std::string delay_target, std::string /*lutin_shared*/, bool fast_mode,
+		const std::vector<RTLIL::Cell*> &/*cells*/, bool show_tempdir, std::string box_file, std::string lut_file,
 		std::string wire_delay, const dict<int,IdString> &box_lookup, bool nomfs
 )
 {
-	module = current_module;
 	map_autoidx = autoidx++;
 
-	if (clk_str != "$")
-	{
-		clk_polarity = true;
-		clk_sig = RTLIL::SigSpec();
-
-		en_polarity = true;
-		en_sig = RTLIL::SigSpec();
-	}
-
-	if (!clk_str.empty() && clk_str != "$")
-	{
-		if (clk_str.find(',') != std::string::npos) {
-			int pos = clk_str.find(',');
-			std::string en_str = clk_str.substr(pos+1);
-			clk_str = clk_str.substr(0, pos);
-			if (en_str[0] == '!') {
-				en_polarity = false;
-				en_str = en_str.substr(1);
-			}
-			if (module->wires_.count(RTLIL::escape_id(en_str)) != 0)
-				en_sig = assign_map(RTLIL::SigSpec(module->wires_.at(RTLIL::escape_id(en_str)), 0));
-		}
-		if (clk_str[0] == '!') {
-			clk_polarity = false;
-			clk_str = clk_str.substr(1);
-		}
-		if (module->wires_.count(RTLIL::escape_id(clk_str)) != 0)
-			clk_sig = assign_map(RTLIL::SigSpec(module->wires_.at(RTLIL::escape_id(clk_str)), 0));
-	}
-
-	if (dff_mode && clk_sig.empty())
-		log_cmd_error("Clock domain %s not found.\n", clk_str.c_str());
-
 	std::string tempdir_name = "/tmp/yosys-abc-XXXXXX";
 	if (!cleanup)
 		tempdir_name[0] = tempdir_name[4] = '_';
@@ -333,20 +293,10 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		} else
 			abc9_script += stringf("source %s", script_file.c_str());
 	} else if (!lut_costs.empty() || !lut_file.empty()) {
-		//bool all_luts_cost_same = true;
-		//for (int this_cost : lut_costs)
-		//	if (this_cost != lut_costs.front())
-		//		all_luts_cost_same = false;
 		abc9_script += fast_mode ? ABC_FAST_COMMAND_LUT : ABC_COMMAND_LUT;
-		//if (all_luts_cost_same && !fast_mode)
-		//	abc9_script += "; lutpack {S}";
 	} else
 		log_abort();
 
-	//if (script_file.empty() && !delay_target.empty())
-	//	for (size_t pos = abc9_script.find("dretime;"); pos != std::string::npos; pos = abc9_script.find("dretime;", pos+1))
-	//		abc9_script = abc9_script.substr(0, pos) + "dretime; retime -o {D};" + abc9_script.substr(pos+8);
-
 	for (size_t pos = abc9_script.find("{D}"); pos != std::string::npos; pos = abc9_script.find("{D}", pos))
 		abc9_script = abc9_script.substr(0, pos) + delay_target + abc9_script.substr(pos+3);
 
@@ -360,7 +310,7 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		for (size_t pos = abc9_script.find("&mfs"); pos != std::string::npos; pos = abc9_script.find("&mfs", pos))
 			abc9_script = abc9_script.erase(pos, strlen("&mfs"));
 
-	abc9_script += stringf("; &write %s/output.aig", tempdir_name.c_str());
+	abc9_script += stringf("; &write -n %s/output.aig", tempdir_name.c_str());
 	abc9_script = add_echos_to_abc9_cmd(abc9_script);
 
 	for (size_t i = 0; i+1 < abc9_script.size(); i++)
@@ -371,39 +321,14 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 	fprintf(f, "%s\n", abc9_script.c_str());
 	fclose(f);
 
-	if (dff_mode || !clk_str.empty())
-	{
-		if (clk_sig.size() == 0)
-			log("No%s clock domain found. Not extracting any FF cells.\n", clk_str.empty() ? "" : " matching");
-		else {
-			log("Found%s %s clock domain: %s", clk_str.empty() ? "" : " matching", clk_polarity ? "posedge" : "negedge", log_signal(clk_sig));
-			if (en_sig.size() != 0)
-				log(", enabled by %s%s", en_polarity ? "" : "!", log_signal(en_sig));
-			log("\n");
-		}
-	}
-
-	bool count_output = false;
-	for (auto port_name : module->ports) {
-		RTLIL::Wire *port_wire = module->wire(port_name);
-		log_assert(port_wire);
-		if (port_wire->port_output) {
-			count_output = true;
-			break;
-		}
-	}
-
+	//bool count_output = false;
 	log_push();
 
-	if (count_output)
+	//if (count_output)
 	{
-		design->selection_stack.emplace_back(false);
-		RTLIL::Selection& sel = design->selection_stack.back();
-		sel.select(module);
+		handle_loops(design, module);
 
-		handle_loops(design);
-
-		Pass::call(design, "aigmap");
+		Pass::call(design, "aigmap -select");
 
 		//log("Extracted %d gates and %d wires to a netlist network with %d inputs and %d outputs.\n",
 		//		count_gates, GetSize(signal_list), count_input, count_output);
@@ -421,15 +346,13 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		log_assert(!design->module(ID($__abc9__)));
 		{
 			AigerReader reader(design, ifs, ID($__abc9__), "" /* clk_name */, buffer.c_str() /* map_filename */, true /* wideports */);
-			reader.parse_xaiger();
+			reader.parse_xaiger(box_lookup);
 		}
 		ifs.close();
-		Pass::call(design, stringf("write_verilog -noexpr -norename"));
+		Pass::call_on_module(design, design->module(ID($__abc9__)), stringf("write_verilog -noexpr -norename -selected"));
 		design->remove(design->module(ID($__abc9__)));
 #endif
 
-		design->selection_stack.pop_back();
-
 		log_header(design, "Executing ABC9.\n");
 
 		if (!lut_costs.empty()) {
@@ -479,7 +402,7 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		ifs.close();
 
 #if 0
-		Pass::call(design, stringf("write_verilog -noexpr -norename"));
+		Pass::call_on_module(design, design->module(ID($__abc9__)), stringf("write_verilog -noexpr -norename -selected"));
 #endif
 
 		log_header(design, "Re-integrating ABC9 results.\n");
@@ -487,33 +410,16 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		if (mapped_mod == NULL)
 			log_error("ABC output file does not contain a module `$__abc9__'.\n");
 
-		pool<RTLIL::SigBit> output_bits;
 		for (auto &it : mapped_mod->wires_) {
 			RTLIL::Wire *w = it.second;
 			RTLIL::Wire *remap_wire = module->addWire(remap_name(w->name), GetSize(w));
 			if (markgroups) remap_wire->attributes[ID(abcgroup)] = map_autoidx;
-			if (w->port_output) {
-				RTLIL::Wire *wire = module->wire(w->name);
-				log_assert(wire);
-				for (int i = 0; i < GetSize(w); i++)
-					output_bits.insert({wire, i});
-			}
-		}
-
-		for (auto &it : module->connections_) {
-			auto &signal = it.first;
-			auto bits = signal.bits();
-			for (auto &b : bits)
-				if (output_bits.count(b))
-					b = module->addWire(NEW_ID);
-			signal = std::move(bits);
 		}
 
 		dict<IdString, bool> abc9_box;
 		vector<RTLIL::Cell*> boxes;
-		for (const auto &it : module->cells_) {
-			auto cell = it.second;
-			if (cell->type.in(ID($_AND_), ID($_NOT_))) {
+		for (auto cell : module->selected_cells()) {
+			if (cell->type.in(ID($_AND_), ID($_NOT_), ID($__ABC9_FF_))) {
 				module->remove(cell);
 				continue;
 			}
@@ -522,8 +428,16 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 				RTLIL::Module* box_module = design->module(cell->type);
 				jt = abc9_box.insert(std::make_pair(cell->type, box_module && box_module->attributes.count(ID(abc9_box_id)))).first;
 			}
-			if (jt->second)
-				boxes.emplace_back(cell);
+			if (jt->second) {
+				auto kt = cell->attributes.find("\\abc9_keep");
+				bool abc9_keep = false;
+				if (kt != cell->attributes.end()) {
+					abc9_keep = kt->second.as_bool();
+					cell->attributes.erase(kt);
+				}
+				if (!abc9_keep)
+					boxes.emplace_back(cell);
+			}
 		}
 
 		dict<SigBit, pool<IdString>> bit_drivers, bit_users;
@@ -532,19 +446,19 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 		dict<SigBit, std::vector<RTLIL::Cell*>> bit2sinks;
 
 		std::map<IdString, int> cell_stats;
-		for (auto c : mapped_mod->cells())
+		for (auto mapped_cell : mapped_mod->cells())
 		{
-			toposort.node(c->name);
+			toposort.node(mapped_cell->name);
 
 			RTLIL::Cell *cell = nullptr;
-			if (c->type == ID($_NOT_)) {
-				RTLIL::SigBit a_bit = c->getPort(ID::A);
-				RTLIL::SigBit y_bit = c->getPort(ID::Y);
-				bit_users[a_bit].insert(c->name);
-				bit_drivers[y_bit].insert(c->name);
+			if (mapped_cell->type == ID($_NOT_)) {
+				RTLIL::SigBit a_bit = mapped_cell->getPort(ID::A);
+				RTLIL::SigBit y_bit = mapped_cell->getPort(ID::Y);
+				bit_users[a_bit].insert(mapped_cell->name);
+				bit_drivers[y_bit].insert(mapped_cell->name);
 
 				if (!a_bit.wire) {
-					c->setPort(ID::Y, module->addWire(NEW_ID));
+					mapped_cell->setPort(ID::Y, module->addWire(NEW_ID));
 					RTLIL::Wire *wire = module->wire(remap_name(y_bit.wire->name));
 					log_assert(wire);
 					module->connect(RTLIL::SigBit(wire, y_bit.offset), State::S1);
@@ -568,7 +482,7 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 					if (!driver_lut) {
 						// If a driver couldn't be found (could be from PI or box CI)
 						// then implement using a LUT
-						cell = module->addLut(remap_name(stringf("%s$lut", c->name.c_str())),
+						cell = module->addLut(remap_name(stringf("%s$lut", mapped_cell->name.c_str())),
 								RTLIL::SigBit(module->wires_.at(remap_name(a_bit.wire->name)), a_bit.offset),
 								RTLIL::SigBit(module->wires_.at(remap_name(y_bit.wire->name)), y_bit.offset),
 								RTLIL::Const::from_string("01"));
@@ -576,7 +490,7 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 						cell_stats[ID($lut)]++;
 					}
 					else
-						not2drivers[c] = driver_lut;
+						not2drivers[mapped_cell] = driver_lut;
 					continue;
 				}
 				else
@@ -584,24 +498,26 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 				if (cell && markgroups) cell->attributes[ID(abcgroup)] = map_autoidx;
 				continue;
 			}
-			cell_stats[c->type]++;
+			cell_stats[mapped_cell->type]++;
 
 			RTLIL::Cell *existing_cell = nullptr;
-			if (c->type == ID($lut)) {
-				if (GetSize(c->getPort(ID::A)) == 1 && c->getParam(ID(LUT)) == RTLIL::Const::from_string("01")) {
-					SigSpec my_a = module->wires_.at(remap_name(c->getPort(ID::A).as_wire()->name));
-					SigSpec my_y = module->wires_.at(remap_name(c->getPort(ID::Y).as_wire()->name));
+			if (mapped_cell->type.in(ID($lut), ID($__ABC9_FF_))) {
+				if (mapped_cell->type == ID($lut) &&
+						GetSize(mapped_cell->getPort(ID::A)) == 1 &&
+						mapped_cell->getParam(ID(LUT)) == RTLIL::Const::from_string("01")) {
+					SigSpec my_a = module->wires_.at(remap_name(mapped_cell->getPort(ID::A).as_wire()->name));
+					SigSpec my_y = module->wires_.at(remap_name(mapped_cell->getPort(ID::Y).as_wire()->name));
 					module->connect(my_y, my_a);
-					if (markgroups) c->attributes[ID(abcgroup)] = map_autoidx;
+					if (markgroups) mapped_cell->attributes[ID(abcgroup)] = map_autoidx;
 					log_abort();
 					continue;
 				}
-				cell = module->addCell(remap_name(c->name), c->type);
+				cell = module->addCell(remap_name(mapped_cell->name), mapped_cell->type);
 			}
 			else {
-				existing_cell = module->cell(c->name);
+				existing_cell = module->cell(mapped_cell->name);
 				log_assert(existing_cell);
-				cell = module->addCell(remap_name(c->name), c->type);
+				cell = module->addCell(remap_name(mapped_cell->name), mapped_cell->type);
 			}
 
 			if (markgroups) cell->attributes[ID(abcgroup)] = map_autoidx;
@@ -610,10 +526,13 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 				cell->attributes = existing_cell->attributes;
 			}
 			else {
-				cell->parameters = c->parameters;
-				cell->attributes = c->attributes;
+				cell->parameters = mapped_cell->parameters;
+				cell->attributes = mapped_cell->attributes;
 			}
-			for (auto &conn : c->connections()) {
+
+			RTLIL::Module* box_module = design->module(mapped_cell->type);
+			auto abc9_flop = box_module && box_module->attributes.count("\\abc9_flop");
+			for (auto &conn : mapped_cell->connections()) {
 				RTLIL::SigSpec newsig;
 				for (auto c : conn.second.chunks()) {
 					if (c.width == 0)
@@ -625,15 +544,17 @@ void abc9_module(RTLIL::Design *design, RTLIL::Module *current_module, std::stri
 				}
 				cell->setPort(conn.first, newsig);
 
-				if (cell->input(conn.first)) {
-					for (auto i : newsig)
-						bit2sinks[i].push_back(cell);
-					for (auto i : conn.second)
-						bit_users[i].insert(c->name);
+				if (!abc9_flop) {
+					if (cell->input(conn.first)) {
+						for (auto i : newsig)
+							bit2sinks[i].push_back(cell);
+						for (auto i : conn.second)
+							bit_users[i].insert(mapped_cell->name);
+					}
+					if (cell->output(conn.first))
+						for (auto i : conn.second)
+							bit_drivers[i].insert(mapped_cell->name);
 				}
-				if (cell->output(conn.first))
-					for (auto i : conn.second)
-						bit_drivers[i].insert(c->name);
 			}
 		}
 
@@ -798,10 +719,10 @@ clone_lut:
 
 		design->remove(mapped_mod);
 	}
-	else
-	{
-		log("Don't call ABC as there is nothing to map.\n");
-	}
+	//else
+	//{
+	//	log("Don't call ABC as there is nothing to map.\n");
+	//}
 
 	if (cleanup)
 	{
@@ -842,7 +763,7 @@ struct Abc9Pass : public Pass {
 		log("        if no -script parameter is given, the following scripts are used:\n");
 		log("\n");
 		log("        for -lut/-luts (only one LUT size):\n");
-		log("%s\n", fold_abc9_cmd(ABC_COMMAND_LUT /*"; lutpack {S}"*/).c_str());
+		log("%s\n", fold_abc9_cmd(ABC_COMMAND_LUT).c_str());
 		log("\n");
 		log("        for -lut/-luts (different LUT sizes):\n");
 		log("%s\n", fold_abc9_cmd(ABC_COMMAND_LUT).c_str());
@@ -858,8 +779,6 @@ struct Abc9Pass : public Pass {
 		log("        set delay target. the string {D} in the default scripts above is\n");
 		log("        replaced by this option when used, and an empty string otherwise\n");
 		log("        (indicating best possible delay).\n");
-//		log("        This also replaces 'dretime' with 'dretime; retime -o {D}' in the\n");
-//		log("        default scripts above.\n");
 		log("\n");
 //		log("    -S <num>\n");
 //		log("        maximum number of LUT inputs shared.\n");
@@ -881,19 +800,6 @@ struct Abc9Pass : public Pass {
 		log("        generate netlist using luts. Use the specified costs for luts with 1,\n");
 		log("        2, 3, .. inputs.\n");
 		log("\n");
-//		log("    -dff\n");
-//		log("        also pass $_DFF_?_ and $_DFFE_??_ cells through ABC. modules with many\n");
-//		log("        clock domains are automatically partitioned in clock domains and each\n");
-//		log("        domain is passed through ABC independently.\n");
-//		log("\n");
-//		log("    -clk [!]<clock-signal-name>[,[!]<enable-signal-name>]\n");
-//		log("        use only the specified clock domain. this is like -dff, but only FF\n");
-//		log("        cells that belong to the specified clock domain are used.\n");
-//		log("\n");
-//		log("    -keepff\n");
-//		log("        set the \"keep\" attribute on flip-flop output wires. (and thus preserve\n");
-//		log("        them, for example for equivalence checking.)\n");
-//		log("\n");
 		log("    -nocleanup\n");
 		log("        when this option is used, the temporary files created by this pass\n");
 		log("        are not removed. this is useful for debugging.\n");
@@ -914,8 +820,17 @@ struct Abc9Pass : public Pass {
 		log("internally. This is not going to \"run ABC on your design\". It will instead run\n");
 		log("ABC on logic snippets extracted from your design. You will not get any useful\n");
 		log("output when passing an ABC script that writes a file. Instead write your full\n");
-		log("design as BLIF file with write_blif and then load that into ABC externally if\n");
-		log("you want to use ABC to convert your design into another format.\n");
+		log("design as an XAIGER file with write_xaiger and then load that into ABC externally\n");
+		log("if you want to use ABC to convert your design into another format.\n");
+		log("\n");
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("Delay targets can also be specified on a per clock basis by attaching a\n");
+		log("'(* abc9_period = <int> *)' attribute onto clock wires (specifically, onto wires\n");
+		log("that appear inside any special '$abc9_clock' wires inserted by abc9_map.v). This\n");
+		log("can be achieved by modifying the source directly, or through a `setattr`\n");
+		log("invocation. Since such attributes cannot yet be propagated through a\n");
+		log("hierarchical design (whether or not it has been uniquified) it is recommended\n");
+		log("that the design be flattened when using this feature.\n");
 		log("\n");
 		log("[1] http://www.eecs.berkeley.edu/~alanmi/abc/\n");
 		log("\n");
@@ -925,8 +840,6 @@ struct Abc9Pass : public Pass {
 		log_header(design, "Executing ABC9 pass (technology mapping using ABC9).\n");
 		log_push();
 
-		assign_map.clear();
-
 #ifdef ABCEXTERNAL
 		std::string exe_file = ABCEXTERNAL;
 #else
@@ -934,7 +847,7 @@ struct Abc9Pass : public Pass {
 #endif
 		std::string script_file, clk_str, box_file, lut_file;
 		std::string delay_target, lutin_shared = "-S 1", wire_delay;
-		bool fast_mode = false, dff_mode = false, keepff = false, cleanup = true;
+		bool fast_mode = false, cleanup = true;
 		bool show_tempdir = false;
 		bool nomfs = false;
 		vector<int> lut_costs;
@@ -1025,19 +938,6 @@ struct Abc9Pass : public Pass {
 				fast_mode = true;
 				continue;
 			}
-			//if (arg == "-dff") {
-			//	dff_mode = true;
-			//	continue;
-			//}
-			//if (arg == "-clk" && argidx+1 < args.size()) {
-			//	clk_str = args[++argidx];
-			//	dff_mode = true;
-			//	continue;
-			//}
-			//if (arg == "-keepff") {
-			//	keepff = true;
-			//	continue;
-			//}
 			if (arg == "-nocleanup") {
 				cleanup = false;
 				continue;
@@ -1135,48 +1035,40 @@ struct Abc9Pass : public Pass {
 			}
 		}
 
-		for (auto mod : design->selected_modules())
+		SigMap assign_map;
+		CellTypes ct(design);
+		for (auto module : design->selected_modules())
 		{
-			if (mod->attributes.count(ID(abc9_box_id)))
+			if (module->attributes.count(ID(abc9_box_id)))
 				continue;
 
-			if (mod->processes.size() > 0) {
-				log("Skipping module %s as it contains processes.\n", log_id(mod));
+			if (module->processes.size() > 0) {
+				log("Skipping module %s as it contains processes.\n", log_id(module));
 				continue;
 			}
 
-			assign_map.set(mod);
-
-			if (!dff_mode || !clk_str.empty()) {
-				abc9_module(design, mod, script_file, exe_file, cleanup, lut_costs, dff_mode, clk_str, keepff,
-						delay_target, lutin_shared, fast_mode, show_tempdir,
-						box_file, lut_file, wire_delay, box_lookup, nomfs);
-				continue;
-			}
+			assign_map.set(module);
 
-			CellTypes ct(design);
+			typedef SigSpec clkdomain_t;
+			dict<clkdomain_t, int> clk_to_mergeability;
 
-			std::vector<RTLIL::Cell*> all_cells = mod->selected_cells();
-			std::set<RTLIL::Cell*> unassigned_cells(all_cells.begin(), all_cells.end());
+			const std::vector<RTLIL::Cell*> all_cells = module->selected_cells();
+#if 0
+			pool<RTLIL::Cell*> unassigned_cells(all_cells.begin(), all_cells.end());
 
-			std::set<RTLIL::Cell*> expand_queue, next_expand_queue;
-			std::set<RTLIL::Cell*> expand_queue_up, next_expand_queue_up;
-			std::set<RTLIL::Cell*> expand_queue_down, next_expand_queue_down;
+			pool<RTLIL::Cell*> expand_queue, next_expand_queue;
+			pool<RTLIL::Cell*> expand_queue_up, next_expand_queue_up;
+			pool<RTLIL::Cell*> expand_queue_down, next_expand_queue_down;
 
-			typedef tuple<bool, RTLIL::SigSpec, bool, RTLIL::SigSpec> clkdomain_t;
-			std::map<clkdomain_t, std::vector<RTLIL::Cell*>> assigned_cells;
+			std::map<clkdomain_t, pool<RTLIL::IdString>> assigned_cells;
 			std::map<RTLIL::Cell*, clkdomain_t> assigned_cells_reverse;
 
-			std::map<RTLIL::Cell*, std::set<RTLIL::SigBit>> cell_to_bit, cell_to_bit_up, cell_to_bit_down;
-			std::map<RTLIL::SigBit, std::set<RTLIL::Cell*>> bit_to_cell, bit_to_cell_up, bit_to_cell_down;
+			std::map<RTLIL::Cell*, pool<RTLIL::SigBit>> cell_to_bit, cell_to_bit_up, cell_to_bit_down;
+			std::map<RTLIL::SigBit, pool<RTLIL::Cell*>> bit_to_cell, bit_to_cell_up, bit_to_cell_down;
 
 			for (auto cell : all_cells)
-			{
-				clkdomain_t key;
-
 				for (auto &conn : cell->connections())
-				for (auto bit : conn.second) {
-					bit = assign_map(bit);
+				for (auto bit : assign_map(conn.second))
 					if (bit.wire != nullptr) {
 						cell_to_bit[cell].insert(bit);
 						bit_to_cell[bit].insert(cell);
@@ -1189,37 +1081,75 @@ struct Abc9Pass : public Pass {
 							bit_to_cell_up[bit].insert(cell);
 						}
 					}
-				}
+#endif
 
-				if (cell->type.in(ID($_DFF_N_), ID($_DFF_P_)))
-				{
-					key = clkdomain_t(cell->type == ID($_DFF_P_), assign_map(cell->getPort(ID(C))), true, RTLIL::SigSpec());
-				}
-				else
-				if (cell->type.in(ID($_DFFE_NN_), ID($_DFFE_NP_), ID($_DFFE_PN_), ID($_DFFE_PP_)))
-				{
-					bool this_clk_pol = cell->type.in(ID($_DFFE_PN_), ID($_DFFE_PP_));
-					bool this_en_pol = cell->type.in(ID($_DFFE_NP_), ID($_DFFE_PP_));
-					key = clkdomain_t(this_clk_pol, assign_map(cell->getPort(ID(C))), this_en_pol, assign_map(cell->getPort(ID(E))));
-				}
-				else
+			for (auto cell : all_cells) {
+				auto inst_module = design->module(cell->type);
+				if (!inst_module || !inst_module->attributes.count("\\abc9_flop")
+						|| cell->get_bool_attribute("\\abc9_keep"))
 					continue;
 
+				Wire *abc9_clock_wire = module->wire(stringf("%s.$abc9_clock", cell->name.c_str()));
+				if (abc9_clock_wire == NULL)
+					log_error("'%s$abc9_clock' is not a wire present in module '%s'.\n", cell->name.c_str(), log_id(module));
+				SigSpec abc9_clock = assign_map(abc9_clock_wire);
+
+				clkdomain_t key(abc9_clock);
+#if 0
 				unassigned_cells.erase(cell);
-				expand_queue.insert(cell);
 				expand_queue_up.insert(cell);
-				expand_queue_down.insert(cell);
-
-				assigned_cells[key].push_back(cell);
+				assigned_cells[key].insert(cell->name);
 				assigned_cells_reverse[cell] = key;
+#endif
+
+				auto r = clk_to_mergeability.insert(std::make_pair(abc9_clock, clk_to_mergeability.size() + 1));
+				auto r2 YS_ATTRIBUTE(unused) = cell->attributes.insert(std::make_pair(ID(abc9_mergeability), r.first->second));
+				log_assert(r2.second);
+
+				Wire *abc9_init_wire = module->wire(stringf("%s.$abc9_init", cell->name.c_str()));
+				if (abc9_init_wire == NULL)
+				    log_error("'%s.$abc9_init' is not a wire present in module '%s'.\n", cell->name.c_str(), log_id(module));
+				log_assert(GetSize(abc9_init_wire) == 1);
+				SigSpec abc9_init = assign_map(abc9_init_wire);
+				if (!abc9_init.is_fully_const())
+				    log_error("'%s.$abc9_init' is not a constant wire present in module '%s'.\n", cell->name.c_str(), log_id(module));
+				r2 = cell->attributes.insert(std::make_pair(ID(abc9_init), abc9_init.as_const()));
+				log_assert(r2.second);
+
+#if 0
+				// Also assign these special ABC9 cells to the
+				//   same clock domain
+				for (auto b : cell_to_bit_down[cell])
+				for (auto c : bit_to_cell_down[b])
+					if (c->type == "$__ABC9_FF_") {
+						cell = c;
+						unassigned_cells.erase(cell);
+						assigned_cells[key].insert(cell->name);
+						assigned_cells_reverse[cell] = key;
+						break;
+					}
+				for (auto b : cell_to_bit_down[cell])
+				for (auto c : bit_to_cell_down[b])
+					if (c->type == "$__ABC9_ASYNC") {
+						cell = c;
+						unassigned_cells.erase(cell);
+						assigned_cells[key].insert(cell->name);
+						assigned_cells_reverse[cell] = key;
+						break;
+					}
+
+				expand_queue.insert(cell);
+				expand_queue_down.insert(cell);
+#endif
 			}
 
+#if 0
 			while (!expand_queue_up.empty() || !expand_queue_down.empty())
 			{
 				if (!expand_queue_up.empty())
 				{
 					RTLIL::Cell *cell = *expand_queue_up.begin();
-					clkdomain_t key = assigned_cells_reverse.at(cell);
+					auto key = assigned_cells_reverse.at(cell);
 					expand_queue_up.erase(cell);
 
 					for (auto bit : cell_to_bit_up[cell])
@@ -1227,7 +1157,7 @@ struct Abc9Pass : public Pass {
 						if (unassigned_cells.count(c)) {
 							unassigned_cells.erase(c);
 							next_expand_queue_up.insert(c);
-							assigned_cells[key].push_back(c);
+							assigned_cells[key].insert(c->name);
 							assigned_cells_reverse[c] = key;
 							expand_queue.insert(c);
 						}
@@ -1236,7 +1166,7 @@ struct Abc9Pass : public Pass {
 				if (!expand_queue_down.empty())
 				{
 					RTLIL::Cell *cell = *expand_queue_down.begin();
-					clkdomain_t key = assigned_cells_reverse.at(cell);
+					auto key = assigned_cells_reverse.at(cell);
 					expand_queue_down.erase(cell);
 
 					for (auto bit : cell_to_bit_down[cell])
@@ -1244,7 +1174,7 @@ struct Abc9Pass : public Pass {
 						if (unassigned_cells.count(c)) {
 							unassigned_cells.erase(c);
 							next_expand_queue_up.insert(c);
-							assigned_cells[key].push_back(c);
+							assigned_cells[key].insert(c->name);
 							assigned_cells_reverse[c] = key;
 							expand_queue.insert(c);
 						}
@@ -1259,7 +1189,7 @@ struct Abc9Pass : public Pass {
 			while (!expand_queue.empty())
 			{
 				RTLIL::Cell *cell = *expand_queue.begin();
-				clkdomain_t key = assigned_cells_reverse.at(cell);
+				auto key = assigned_cells_reverse.at(cell);
 				expand_queue.erase(cell);
 
 				for (auto bit : cell_to_bit.at(cell)) {
@@ -1267,7 +1197,7 @@ struct Abc9Pass : public Pass {
 						if (unassigned_cells.count(c)) {
 							unassigned_cells.erase(c);
 							next_expand_queue.insert(c);
-							assigned_cells[key].push_back(c);
+							assigned_cells[key].insert(c->name);
 							assigned_cells_reverse[c] = key;
 						}
 					bit_to_cell[bit].clear();
@@ -1277,32 +1207,48 @@ struct Abc9Pass : public Pass {
 					expand_queue.swap(next_expand_queue);
 			}
 
-			clkdomain_t key(true, RTLIL::SigSpec(), true, RTLIL::SigSpec());
+			clkdomain_t key;
 			for (auto cell : unassigned_cells) {
-				assigned_cells[key].push_back(cell);
+				assigned_cells[key].insert(cell->name);
 				assigned_cells_reverse[cell] = key;
 			}
 
 			log_header(design, "Summary of detected clock domains:\n");
-			for (auto &it : assigned_cells)
-				log("  %d cells in clk=%s%s, en=%s%s\n", GetSize(it.second),
-						std::get<0>(it.first) ? "" : "!", log_signal(std::get<1>(it.first)),
-						std::get<2>(it.first) ? "" : "!", log_signal(std::get<3>(it.first)));
+			for (auto &it : assigned_cells) {
+				log("  %d cells in clk=%s\n", GetSize(it.second), log_signal(it.first));
+            }
+#endif
 
+			design->selected_active_module = module->name.str();
+#if 0
+			design->selection_stack.emplace_back(false);
 			for (auto &it : assigned_cells) {
-				clk_polarity = std::get<0>(it.first);
-				clk_sig = assign_map(std::get<1>(it.first));
-				en_polarity = std::get<2>(it.first);
-				en_sig = assign_map(std::get<3>(it.first));
-				abc9_module(design, mod, script_file, exe_file, cleanup, lut_costs, !clk_sig.empty(), "$",
-						keepff, delay_target, lutin_shared, fast_mode, show_tempdir,
+				std::string target = delay_target;
+				if (target.empty()) {
+					for (auto b : assign_map(it.first))
+						if (b.wire) {
+							auto jt = b.wire->attributes.find("\\abc9_period");
+							if (jt != b.wire->attributes.end()) {
+								target = stringf("-D %d", jt->second.as_int());
+								log("Target period = %s ps for clock domain %s\n", target.c_str(), log_signal(it.first));
+								break;
+							}
+						}
+				}
+				RTLIL::Selection& sel = design->selection_stack.back();
+				sel.selected_members[module->name] = std::move(it.second);
+#endif
+				abc9_module(design, module, script_file, exe_file, cleanup, lut_costs,
+						delay_target, lutin_shared, fast_mode, all_cells, show_tempdir,
 						box_file, lut_file, wire_delay, box_lookup, nomfs);
-				assign_map.set(mod);
+#if 0
+				assign_map.set(module);
 			}
+			design->selection_stack.pop_back();
+#endif
+			design->selected_active_module.clear();
 		}
 
-		assign_map.clear();
-
 		log_pop();
 	}
 } Abc9Pass;