X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=backends%2Faiger%2Fxaiger.cc;h=fd0620cac4ea43752be3e6e7194b48d72dec263b;hb=4be417f6e15ee3f3d8da8cd75d8405b90d5b32ba;hp=66ab3878e9f4c9181571c9eb5a5d9858bdf0896f;hpb=55a3638c71229e2730e1d0f7340f6c9d4087522d;p=yosys.git

diff --git a/backends/aiger/xaiger.cc b/backends/aiger/xaiger.cc
index 66ab3878e..fd0620cac 100644
--- a/backends/aiger/xaiger.cc
+++ b/backends/aiger/xaiger.cc
@@ -2,7 +2,7 @@
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
- *  Copyright (C) 2019  Eddie Hung <eddie@fpgeh.com>
+ *                2019  Eddie Hung <eddie@fpgeh.com>
  *
  *  Permission to use, copy, modify, and/or distribute this software for any
  *  purpose with or without fee is hereby granted, provided that the above
@@ -20,6 +20,8 @@
 
 #include "kernel/yosys.h"
 #include "kernel/sigtools.h"
+#include "kernel/celltypes.h"
+#include "kernel/utils.h"
 
 USING_YOSYS_NAMESPACE
 PRIVATE_NAMESPACE_BEGIN
@@ -46,9 +48,10 @@ struct XAigerWriter
 	pool<SigBit> input_bits, output_bits;
 	dict<SigBit, SigBit> not_map, ff_map, alias_map;
 	dict<SigBit, pair<SigBit, SigBit>> and_map;
-	pool<SigBit> initstate_bits;
-	vector<std::pair<SigBit,int>> ci_bits, co_bits;
-	dict<IdString, unsigned> type_map;
+	//pool<SigBit> initstate_bits;
+	vector<std::tuple<SigBit,RTLIL::Cell*,RTLIL::IdString,int>> ci_bits;
+	vector<std::tuple<SigBit,RTLIL::Cell*,RTLIL::IdString,int,int>> co_bits;
+	vector<std::pair<SigBit,SigBit>> ff_bits;
 
 	vector<pair<int, int>> aig_gates;
 	vector<int> aig_latchin, aig_latchinit, aig_outputs;
@@ -58,11 +61,11 @@ struct XAigerWriter
 	dict<SigBit, int> ordered_outputs;
 	dict<SigBit, int> ordered_latches;
 
-	dict<SigBit, int> init_inputs;
-	int initstate_ff = 0;
-
 	vector<Cell*> box_list;
 
+	//dict<SigBit, int> init_inputs;
+	//int initstate_ff = 0;
+
 	int mkgate(int a0, int a1)
 	{
 		aig_m++, aig_a++;
@@ -76,10 +79,10 @@ struct XAigerWriter
 		{
 			aig_map[bit] = -1;
 
-			if (initstate_bits.count(bit)) {
-				log_assert(initstate_ff > 0);
-				aig_map[bit] = initstate_ff;
-			} else
+			//if (initstate_bits.count(bit)) {
+			//	log_assert(initstate_ff > 0);
+			//	aig_map[bit] = initstate_ff;
+			//} else
 			if (not_map.count(bit)) {
 				int a = bit2aig(not_map.at(bit)) ^ 1;
 				aig_map[bit] = a;
@@ -102,7 +105,7 @@ struct XAigerWriter
 		return aig_map.at(bit);
 	}
 
-	XAigerWriter(Module *module, bool zinit_mode, bool imode, bool omode, bool bmode) : module(module), zinit_mode(zinit_mode), sigmap(module)
+	XAigerWriter(Module *module, bool zinit_mode, bool imode, bool omode, bool holes_mode=false) : module(module), zinit_mode(zinit_mode), sigmap(module)
 	{
 		pool<SigBit> undriven_bits;
 		pool<SigBit> unused_bits;
@@ -132,6 +135,8 @@ struct XAigerWriter
 						init_map[initsig[i]] = initval[i] == State::S1;
 			}
 
+			bool keep = wire->attributes.count("\\keep");
+
 			for (int i = 0; i < GetSize(wire); i++)
 			{
 				SigBit wirebit(wire, i);
@@ -148,10 +153,13 @@ struct XAigerWriter
 				undriven_bits.insert(bit);
 				unused_bits.insert(bit);
 
-				if (wire->port_input)
-					input_bits.insert(bit);
+				if (wire->port_input || keep) {
+					if (bit != wirebit)
+						alias_map[bit] = wirebit;
+					input_bits.insert(wirebit);
+				}
 
-				if (wire->port_output) {
+				if (wire->port_output || keep) {
 					if (bit != wirebit)
 						alias_map[wirebit] = bit;
 					output_bits.insert(wirebit);
@@ -159,19 +167,59 @@ struct XAigerWriter
 			}
 		}
 
-		for (auto bit : input_bits) {
-			if (!bit.wire->port_output)
-				undriven_bits.erase(bit);
-			// Erase POs that are also PIs
-			output_bits.erase(bit);
-		}
+		for (auto bit : input_bits)
+			undriven_bits.erase(sigmap(bit));
 
 		for (auto bit : output_bits)
 			if (!bit.wire->port_input)
 				unused_bits.erase(bit);
 
+		dict<SigBit, pool<IdString>> bit_drivers, bit_users;
+		TopoSort<IdString, RTLIL::sort_by_id_str> toposort;
+		bool abc_box_seen = false;
+
 		for (auto cell : module->cells())
 		{
+			RTLIL::Module* inst_module = module->design->module(cell->type);
+			bool builtin_type = yosys_celltypes.cell_known(cell->type);
+			bool abc_type = inst_module && inst_module->attributes.count("\\abc_box_id");
+
+			if (!holes_mode) {
+				toposort.node(cell->name);
+				for (const auto &conn : cell->connections()) {
+					if (!builtin_type && !abc_type)
+						continue;
+
+					if (!cell->type.in("$_NOT_", "$_AND_")) {
+						if (builtin_type) {
+							if (conn.first.in("\\Q", "\\CTRL_OUT", "\\RD_DATA"))
+								continue;
+							if (cell->type == "$memrd" && conn.first == "\\DATA")
+								continue;
+						}
+
+						if (inst_module) {
+							RTLIL::Wire* inst_module_port = inst_module->wire(conn.first);
+							log_assert(inst_module_port);
+
+							if (inst_module_port->port_output && inst_module_port->attributes.count("\\abc_flop_q"))
+									continue;
+						}
+					}
+
+					if (cell->input(conn.first)) {
+						// Ignore inout for the sake of topographical ordering
+						if (cell->output(conn.first)) continue;
+						for (auto bit : sigmap(conn.second))
+							bit_users[bit].insert(cell->name);
+					}
+
+					if (cell->output(conn.first))
+						for (auto bit : sigmap(conn.second))
+							bit_drivers[bit].insert(cell->name);
+				}
+			}
+
 			if (cell->type == "$_NOT_")
 			{
 				SigBit A = sigmap(cell->getPort("\\A").as_bit());
@@ -204,68 +252,221 @@ struct XAigerWriter
 				continue;
 			}
 
-			if (cell->type == "$initstate")
-			{
-				SigBit Y = sigmap(cell->getPort("\\Y").as_bit());
-				undriven_bits.erase(Y);
-				initstate_bits.insert(Y);
-				continue;
-			}
-
-			RTLIL::Module* box_module = module->design->module(cell->type);
-			bool abc_box = box_module && box_module->attributes.count("\\abc_box_id");
+			//if (cell->type == "$initstate")
+			//{
+			//	SigBit Y = sigmap(cell->getPort("\\Y").as_bit());
+			//	undriven_bits.erase(Y);
+			//	initstate_bits.insert(Y);
+			//	continue;
+			//}
 
-			for (const auto &c : cell->connections()) {
-				/*if (c.second.is_fully_const()) continue;*/
-				for (auto b : c.second.bits()) {
+			bool inst_flop = inst_module ? inst_module->attributes.count("\\abc_flop") : false;
+			if (inst_flop) {
+				SigBit d, q;
+				for (const auto &c : cell->connections()) {
 					auto is_input = cell->input(c.first);
 					auto is_output = cell->output(c.first);
 					log_assert(is_input || is_output);
-					if (is_input) {
-						/*if (!w->port_input)*/ {
+					RTLIL::Wire* port = inst_module->wire(c.first);
+					for (auto b : c.second.bits()) {
+						if (is_input && port->attributes.count("\\abc_flop_d")) {
+							d = b;
+							SigBit I = sigmap(d);
+							if (I != d)
+								alias_map[I] = d;
+							unused_bits.erase(d);
+						}
+						if (is_output && port->attributes.count("\\abc_flop_q")) {
+							q = b;
+							SigBit O = sigmap(q);
+							if (O != q)
+								alias_map[O] = q;
+							undriven_bits.erase(O);
+						}
+					}
+				}
+				if (!abc_box_seen)
+					abc_box_seen = inst_module->attributes.count("\\abc_box_id");
+
+				ff_bits.emplace_back(d, q);
+			}
+			else if (inst_module && inst_module->attributes.count("\\abc_box_id")) {
+				abc_box_seen = true;
+			}
+			else {
+				for (const auto &c : cell->connections()) {
+					if (c.second.is_fully_const()) continue;
+					for (auto b : c.second.bits()) {
+						Wire *w = b.wire;
+						if (!w) continue;
+						auto is_input = cell->input(c.first);
+						auto is_output = cell->output(c.first);
+						log_assert(is_input || is_output);
+						if (is_input) {
+							if (!w->port_input) {
+								SigBit I = sigmap(b);
+								if (I != b)
+									alias_map[b] = I;
+								output_bits.insert(b);
+								unused_bits.erase(b);
+							}
+						}
+						if (is_output) {
+							input_bits.insert(b);
+							SigBit O = sigmap(b);
+							if (O != b)
+								alias_map[O] = b;
+							undriven_bits.erase(O);
+						}
+					}
+				}
+			}
+
+			//log_warning("Unsupported cell type: %s (%s)\n", log_id(cell->type), log_id(cell));
+		}
+
+		if (abc_box_seen) {
+			for (auto &it : bit_users)
+				if (bit_drivers.count(it.first))
+					for (auto driver_cell : bit_drivers.at(it.first))
+					for (auto user_cell : it.second)
+						toposort.edge(driver_cell, user_cell);
+
+			pool<RTLIL::Module*> abc_carry_modules;
+
+#if 0
+			toposort.analyze_loops = true;
+#endif
+			bool no_loops = toposort.sort();
+#if 0
+			unsigned i = 0;
+			for (auto &it : toposort.loops) {
+				log("  loop %d", i++);
+				for (auto cell : it)
+					log(" %s", log_id(cell));
+				log("\n");
+			}
+#endif
+			log_assert(no_loops);
+
+			for (auto cell_name : toposort.sorted) {
+				RTLIL::Cell *cell = module->cell(cell_name);
+				RTLIL::Module* box_module = module->design->module(cell->type);
+				if (!box_module || !box_module->attributes.count("\\abc_box_id"))
+					continue;
+
+				if (box_module->attributes.count("\\abc_carry") && !abc_carry_modules.count(box_module)) {
+					RTLIL::Wire* carry_in = nullptr, *carry_out = nullptr;
+					RTLIL::Wire* last_in = nullptr, *last_out = nullptr;
+					for (const auto &port_name : box_module->ports) {
+						RTLIL::Wire* w = box_module->wire(port_name);
+						log_assert(w);
+						if (w->port_input) {
+							if (w->attributes.count("\\abc_carry_in")) {
+								log_assert(!carry_in);
+								carry_in = w;
+							}
+							log_assert(!last_in || last_in->port_id < w->port_id);
+							last_in = w;
+						}
+						if (w->port_output) {
+							if (w->attributes.count("\\abc_carry_out")) {
+								log_assert(!carry_out);
+								carry_out = w;
+							}
+							log_assert(!last_out || last_out->port_id < w->port_id);
+							last_out = w;
+						}
+					}
+
+					if (carry_in) {
+						log_assert(last_in);
+						std::swap(box_module->ports[carry_in->port_id-1], box_module->ports[last_in->port_id-1]);
+						std::swap(carry_in->port_id, last_in->port_id);
+					}
+					if (carry_out) {
+						log_assert(last_out);
+						std::swap(box_module->ports[carry_out->port_id-1], box_module->ports[last_out->port_id-1]);
+						std::swap(carry_out->port_id, last_out->port_id);
+					}
+				}
+
+				// Fully pad all unused input connections of this box cell with S0
+				// Fully pad all undriven output connections of this box cell with anonymous wires
+				// NB: Assume box_module->ports are sorted alphabetically
+				//     (as RTLIL::Module::fixup_ports() would do)
+				for (const auto &port_name : box_module->ports) {
+					RTLIL::Wire* w = box_module->wire(port_name);
+					log_assert(w);
+					auto it = cell->connections_.find(port_name);
+					if (w->port_input) {
+						RTLIL::SigSpec rhs;
+						if (it != cell->connections_.end()) {
+							if (GetSize(it->second) < GetSize(w))
+								it->second.append(RTLIL::SigSpec(RTLIL::S0, GetSize(w)-GetSize(it->second)));
+							rhs = it->second;
+						}
+						else {
+							rhs = RTLIL::SigSpec(RTLIL::S0, GetSize(w));
+							cell->setPort(port_name, rhs);
+						}
+
+						int offset = 0;
+						for (const auto &b : rhs.bits()) {
 							SigBit I = sigmap(b);
 							if (I != b)
 								alias_map[b] = I;
-							/*if (!output_bits.count(b))*/
-							if (abc_box)
-								co_bits.emplace_back(b, 0);
-							else if (b.wire) {
-								output_bits.insert(b);
-								if (!b.wire->port_input)
-									unused_bits.erase(b);
-							}
+							co_bits.emplace_back(b, cell, port_name, offset++, 0);
+							unused_bits.erase(b);
 						}
 					}
-					if (is_output) {
-						SigBit O = sigmap(b);
-						/*if (!input_bits.count(O))*/
-						if (abc_box)
-							ci_bits.emplace_back(O, 0);
+					if (w->port_output) {
+						RTLIL::SigSpec rhs;
+						auto it = cell->connections_.find(w->name);
+						if (it != cell->connections_.end()) {
+							if (GetSize(it->second) < GetSize(w))
+								it->second.append(module->addWire(NEW_ID, GetSize(w)-GetSize(it->second)));
+							rhs = it->second;
+						}
 						else {
-							input_bits.insert(O);
-							if (!O.wire->port_output)
-								undriven_bits.erase(O);
+							rhs = module->addWire(NEW_ID, GetSize(w));
+							cell->setPort(port_name, rhs);
+						}
+
+						int offset = 0;
+						for (const auto &b : rhs.bits()) {
+							ci_bits.emplace_back(b, cell, port_name, offset++);
+							SigBit O = sigmap(b);
+							if (O != b)
+								alias_map[O] = b;
+							undriven_bits.erase(O);
+
+							auto jt = input_bits.find(b);
+							if (jt != input_bits.end()) {
+								log_assert(b.wire->attributes.count("\\keep"));
+								input_bits.erase(b);
+							}
 						}
 					}
 				}
-				if (!type_map.count(cell->type))
-					type_map[cell->type] = type_map.size()+1;
+				box_list.emplace_back(cell);
 			}
 
-			if (abc_box)
-				box_list.emplace_back(cell);
-			//log_warning("Unsupported cell type: %s (%s)\n", log_id(cell->type), log_id(cell));
+			// TODO: Free memory from toposort, bit_drivers, bit_users
 		}
 
 		for (auto bit : input_bits) {
 			RTLIL::Wire *wire = bit.wire;
-			// If encountering an inout port, then create a new wire with $inout.out
-			// suffix, make it a PO driven by the existing inout, and inherit existing
-			// inout's drivers
-			if (wire->port_input && wire->port_output && !undriven_bits.count(bit)) {
-				RTLIL::Wire *new_wire = module->wire(wire->name.str() + "$inout.out");
+			// If encountering an inout port, or a keep-ed wire, then create a new wire
+			// with $inout.out suffix, make it a PO driven by the existing inout, and
+			// inherit existing inout's drivers
+			if ((wire->port_input && wire->port_output && !undriven_bits.count(bit))
+					|| wire->attributes.count("\\keep")) {
+				log_assert(input_bits.count(bit) && output_bits.count(bit));
+				RTLIL::IdString wire_name = wire->name.str() + "$inout.out";
+				RTLIL::Wire *new_wire = module->wire(wire_name);
 				if (!new_wire)
-					new_wire = module->addWire(wire->name.str() + "$inout.out", GetSize(wire));
+					new_wire = module->addWire(wire_name, GetSize(wire));
 				SigBit new_bit(new_wire, bit.offset);
 				module->connect(new_bit, bit);
 				if (not_map.count(bit))
@@ -274,27 +475,22 @@ struct XAigerWriter
 					and_map[new_bit] = and_map.at(bit);
 				else if (alias_map.count(bit))
 					alias_map[new_bit] = alias_map.at(bit);
+				else
+					//log_abort();
+					alias_map[new_bit] = bit;
+				output_bits.erase(bit);
 				output_bits.insert(new_bit);
 			}
 		}
 
-		// Do some CI/CO post-processing:
-		// Erase all POs and COs that are undriven
-		for (auto bit : undriven_bits) {
-			//co_bits.erase(bit);
-			output_bits.erase(bit);
-		}
-		// Erase all CIs that are also COs
-		//for (auto bit : co_bits)
-		//	ci_bits.erase(bit);
-		// CIs cannot be undriven
-		for (const auto &c : ci_bits)
-			undriven_bits.erase(c.first);
-
+		// Erase all POs that are undriven
+		if (!holes_mode)
+			for (auto bit : undriven_bits)
+				output_bits.erase(bit);
 		for (auto bit : unused_bits)
 			undriven_bits.erase(bit);
 
-		if (!undriven_bits.empty()) {
+		if (!undriven_bits.empty() && !holes_mode) {
 			undriven_bits.sort();
 			for (auto bit : undriven_bits) {
 				log_warning("Treating undriven bit %s.%s like $anyseq.\n", log_id(module), log_signal(bit));
@@ -304,8 +500,20 @@ struct XAigerWriter
 		}
 
 		init_map.sort();
-		input_bits.sort();
-		output_bits.sort();
+		if (holes_mode) {
+			struct sort_by_port_id {
+				bool operator()(const RTLIL::SigBit& a, const RTLIL::SigBit& b) const {
+					return a.wire->port_id < b.wire->port_id;
+				}
+			};
+			input_bits.sort(sort_by_port_id());
+			output_bits.sort(sort_by_port_id());
+		}
+		else {
+			input_bits.sort();
+			output_bits.sort();
+		}
+
 		not_map.sort();
 		ff_map.sort();
 		and_map.sort();
@@ -313,31 +521,42 @@ struct XAigerWriter
 		aig_map[State::S0] = 0;
 		aig_map[State::S1] = 1;
 
-		for (auto &c : ci_bits) {
+		for (auto bit : input_bits) {
 			aig_m++, aig_i++;
-			c.second = 2*aig_m;
-			aig_map[c.first] = c.second;
+			log_assert(!aig_map.count(bit));
+			aig_map[bit] = 2*aig_m;
 		}
 
-		for (auto bit : input_bits) {
+		for (auto &f : ff_bits) {
+			RTLIL::SigBit bit = f.second;
 			aig_m++, aig_i++;
+			log_assert(!aig_map.count(bit));
 			aig_map[bit] = 2*aig_m;
 		}
 
-		if (imode && input_bits.empty()) {
+		dict<SigBit, int> ff_aig_map;
+		for (auto &c : ci_bits) {
+			RTLIL::SigBit bit = std::get<0>(c);
 			aig_m++, aig_i++;
+			auto r = aig_map.insert(std::make_pair(bit, 2*aig_m));
+			if (!r.second)
+				ff_aig_map[bit] = 2*aig_m;
 		}
 
-		if (zinit_mode)
-		{
-			for (auto it : ff_map) {
-				if (init_map.count(it.first))
-					continue;
-				aig_m++, aig_i++;
-				init_inputs[it.first] = 2*aig_m;
-			}
+		if (imode && input_bits.empty()) {
+			aig_m++, aig_i++;
 		}
 
+		//if (zinit_mode)
+		//{
+		//	for (auto it : ff_map) {
+		//		if (init_map.count(it.first))
+		//			continue;
+		//		aig_m++, aig_i++;
+		//		init_inputs[it.first] = 2*aig_m;
+		//	}
+		//}
+
 		for (auto it : ff_map) {
 			aig_m++, aig_l++;
 			aig_map[it.first] = 2*aig_m;
@@ -348,29 +567,29 @@ struct XAigerWriter
 				aig_latchinit.push_back(init_map.at(it.first) ? 1 : 0);
 		}
 
-		if (!initstate_bits.empty() || !init_inputs.empty()) {
-			aig_m++, aig_l++;
-			initstate_ff = 2*aig_m+1;
-			aig_latchinit.push_back(0);
-		}
-
-		if (zinit_mode)
-		{
-			for (auto it : ff_map)
-			{
-				int l = ordered_latches[it.first];
-
-				if (aig_latchinit.at(l) == 1)
-					aig_map[it.first] ^= 1;
-
-				if (aig_latchinit.at(l) == 2)
-				{
-					int gated_ffout = mkgate(aig_map[it.first], initstate_ff^1);
-					int gated_initin = mkgate(init_inputs[it.first], initstate_ff);
-					aig_map[it.first] = mkgate(gated_ffout^1, gated_initin^1)^1;
-				}
-			}
-		}
+		//if (!initstate_bits.empty() || !init_inputs.empty()) {
+		//	aig_m++, aig_l++;
+		//	initstate_ff = 2*aig_m+1;
+		//	aig_latchinit.push_back(0);
+		//}
+
+		//if (zinit_mode)
+		//{
+		//	for (auto it : ff_map)
+		//	{
+		//		int l = ordered_latches[it.first];
+
+		//		if (aig_latchinit.at(l) == 1)
+		//			aig_map[it.first] ^= 1;
+
+		//		if (aig_latchinit.at(l) == 2)
+		//		{
+		//			int gated_ffout = mkgate(aig_map[it.first], initstate_ff^1);
+		//			int gated_initin = mkgate(init_inputs[it.first], initstate_ff);
+		//			aig_map[it.first] = mkgate(gated_ffout^1, gated_initin^1)^1;
+		//		}
+		//	}
+		//}
 
 		for (auto it : ff_map) {
 			int a = bit2aig(it.second);
@@ -381,13 +600,12 @@ struct XAigerWriter
 				aig_latchin.push_back(a);
 		}
 
-		if (!initstate_bits.empty() || !init_inputs.empty())
-			aig_latchin.push_back(1);
+		//if (!initstate_bits.empty() || !init_inputs.empty())
+		//	aig_latchin.push_back(1);
 
 		for (auto &c : co_bits) {
-			RTLIL::SigBit bit = c.first;
-			c.second = aig_o++;
-			ordered_outputs[bit] = c.second;
+			RTLIL::SigBit bit = std::get<0>(c);
+			std::get<4>(c) = ordered_outputs[bit] = aig_o++;
 			aig_outputs.push_back(bit2aig(bit));
 		}
 
@@ -396,18 +614,19 @@ struct XAigerWriter
 			aig_outputs.push_back(bit2aig(bit));
 		}
 
-		if (omode && output_bits.empty()) {
+		for (auto &f : ff_bits) {
 			aig_o++;
-			aig_outputs.push_back(0);
+			RTLIL::SigBit bit = f.second;
+			aig_outputs.push_back(ff_aig_map.at(bit));
 		}
 
-		if (bmode) {
-			//aig_b++;
+		if (omode && output_bits.empty()) {
+			aig_o++;
 			aig_outputs.push_back(0);
 		}
 	}
 
-	void write_aiger(std::ostream &f, bool ascii_mode, bool miter_mode, bool symbols_mode, bool omode)
+	void write_aiger(std::ostream &f, bool ascii_mode, bool omode)
 	{
 		int aig_obc = aig_o;
 		int aig_obcj = aig_obc;
@@ -484,76 +703,9 @@ struct XAigerWriter
 			}
 		}
 
-		if (symbols_mode)
-		{
-			dict<string, vector<string>> symbols;
-
-			bool output_seen = false;
-			for (auto wire : module->wires())
-			{
-				//if (wire->name[0] == '$')
-				//	continue;
-
-				SigSpec sig = sigmap(wire);
-
-				for (int i = 0; i < GetSize(wire); i++)
-				{
-					RTLIL::SigBit b(wire, i);
-					if (input_bits.count(b)) {
-						int a = aig_map.at(sig[i]);
-						log_assert((a & 1) == 0);
-						if (GetSize(wire) != 1)
-							symbols[stringf("i%d", (a >> 1)-1)].push_back(stringf("%s[%d]", log_id(wire), i));
-						else
-							symbols[stringf("i%d", (a >> 1)-1)].push_back(stringf("%s", log_id(wire)));
-					}
-
-					if (output_bits.count(b)) {
-						int o = ordered_outputs.at(b);
-						output_seen = !miter_mode;
-						if (GetSize(wire) != 1)
-							symbols[stringf("%c%d", miter_mode ? 'b' : 'o', o)].push_back(stringf("%s[%d]", log_id(wire), i));
-						else
-							symbols[stringf("%c%d", miter_mode ? 'b' : 'o', o)].push_back(stringf("%s", log_id(wire)));
-					}
-
-					if (init_inputs.count(sig[i])) {
-						int a = init_inputs.at(sig[i]);
-						log_assert((a & 1) == 0);
-						if (GetSize(wire) != 1)
-							symbols[stringf("i%d", (a >> 1)-1)].push_back(stringf("init:%s[%d]", log_id(wire), i));
-						else
-							symbols[stringf("i%d", (a >> 1)-1)].push_back(stringf("init:%s", log_id(wire)));
-					}
-
-					if (ordered_latches.count(sig[i])) {
-						int l = ordered_latches.at(sig[i]);
-						const char *p = (zinit_mode && (aig_latchinit.at(l) == 1)) ? "!" : "";
-						if (GetSize(wire) != 1)
-							symbols[stringf("l%d", l)].push_back(stringf("%s%s[%d]", p, log_id(wire), i));
-						else
-							symbols[stringf("l%d", l)].push_back(stringf("%s%s", p, log_id(wire)));
-					}
-				}
-			}
-
-			if (omode && !output_seen)
-				symbols["o0"].push_back("__dummy_o__");
-
-			symbols.sort();
-
-			for (auto &sym : symbols) {
-				f << sym.first;
-				std::sort(sym.second.begin(), sym.second.end());
-				for (auto &s : sym.second)
-					f << " " << s;
-				f << std::endl;
-			}
-		}
-
 		f << "c";
 
-		if (!box_list.empty()) {
+		if (!box_list.empty() || !ff_bits.empty()) {
 			std::stringstream h_buffer;
 			auto write_h_buffer = [&h_buffer](int i32) {
 				// TODO: Don't assume we're on little endian
@@ -568,49 +720,79 @@ struct XAigerWriter
 			if (omode && num_outputs == 0)
 				num_outputs = 1;
 			write_h_buffer(1);
-			write_h_buffer(input_bits.size() + ci_bits.size());
-			write_h_buffer(num_outputs + co_bits.size());
-			write_h_buffer(input_bits.size());
-			write_h_buffer(num_outputs);
+			log_debug("ciNum = %zu\n", input_bits.size() + ff_bits.size() + ci_bits.size());
+			write_h_buffer(input_bits.size() + ff_bits.size() + ci_bits.size());
+			log_debug("coNum = %zu\n", num_outputs + ff_bits.size() + co_bits.size());
+			write_h_buffer(num_outputs + ff_bits.size()+ co_bits.size());
+			log_debug("piNum = %zu\n", input_bits.size() + ff_bits.size());
+			write_h_buffer(input_bits.size()+ ff_bits.size());
+			log_debug("poNum = %zu\n", num_outputs + ff_bits.size());
+			write_h_buffer(num_outputs + ff_bits.size());
+			log_debug("boxNum = %zu\n", box_list.size());
 			write_h_buffer(box_list.size());
 
 			RTLIL::Module *holes_module = nullptr;
 			holes_module = module->design->addModule("\\__holes__");
+			log_assert(holes_module);
 
+			int port_id = 1;
+			int box_count = 0;
 			for (auto cell : box_list) {
+				RTLIL::Module* box_module = module->design->module(cell->type);
 				int box_inputs = 0, box_outputs = 0;
-				int box_id = module->design->module(cell->type)->attributes.at("\\abc_box_id").as_int();
 				Cell *holes_cell = nullptr;
-				if (holes_module && !holes_module->cell(stringf("\\u%d", box_id)))
-					holes_cell = holes_module->addCell(stringf("\\u%d", box_id), cell->type);
-				RTLIL::Wire *holes_wire;
-				int num_inputs = 0;
-				for (const auto &c : cell->connections()) {
-					if (cell->input(c.first)) {
-						box_inputs += c.second.size();
-						if (holes_cell) {
-							holes_wire = holes_module->wire(stringf("\\i%d", num_inputs));
+				if (box_module->get_bool_attribute("\\whitebox")) {
+					holes_cell = holes_module->addCell(cell->name, cell->type);
+					holes_cell->parameters = cell->parameters;
+				}
+
+				// NB: Assume box_module->ports are sorted alphabetically
+				//     (as RTLIL::Module::fixup_ports() would do)
+				for (const auto &port_name : box_module->ports) {
+					RTLIL::Wire *w = box_module->wire(port_name);
+					log_assert(w);
+					RTLIL::Wire *holes_wire;
+					RTLIL::SigSpec port_wire;
+					if (w->port_input) {
+						for (int i = 0; i < GetSize(w); i++) {
+							box_inputs++;
+							holes_wire = holes_module->wire(stringf("\\i%d", box_inputs));
 							if (!holes_wire) {
-								holes_wire = holes_module->addWire(stringf("\\i%d", num_inputs));
+								holes_wire = holes_module->addWire(stringf("\\i%d", box_inputs));
 								holes_wire->port_input = true;
+								holes_wire->port_id = port_id++;
+								holes_module->ports.push_back(holes_wire->name);
 							}
-							++num_inputs;
-							holes_cell->setPort(c.first, holes_wire);
+							if (holes_cell)
+								port_wire.append(holes_wire);
 						}
+						if (!port_wire.empty())
+							holes_cell->setPort(w->name, port_wire);
 					}
-					if (cell->output(c.first)) {
-						box_outputs += c.second.size();
-						if (holes_cell) {
-							holes_wire = holes_module->addWire(stringf("\\%s.%s", cell->type.c_str(), c.first.c_str()));
+					if (w->port_output) {
+						box_outputs += GetSize(w);
+						for (int i = 0; i < GetSize(w); i++) {
+							if (GetSize(w) == 1)
+								holes_wire = holes_module->addWire(stringf("%s.%s", cell->name.c_str(), w->name.c_str()));
+							else
+								holes_wire = holes_module->addWire(stringf("%s.%s[%d]", cell->name.c_str(), w->name.c_str(), i));
 							holes_wire->port_output = true;
-							holes_cell->setPort(c.first, holes_wire);
+							holes_wire->port_id = port_id++;
+							holes_module->ports.push_back(holes_wire->name);
+							if (holes_cell)
+								port_wire.append(holes_wire);
+							else
+								holes_module->connect(holes_wire, RTLIL::S0);
 						}
+						if (!port_wire.empty())
+							holes_cell->setPort(w->name, port_wire);
 					}
 				}
+
 				write_h_buffer(box_inputs);
 				write_h_buffer(box_outputs);
-				write_h_buffer(box_id);
-				write_h_buffer(0 /* OldBoxNum */);
+				write_h_buffer(box_module->attributes.at("\\abc_box_id").as_int());
+				write_h_buffer(box_count++);
 			}
 
 			f << "h";
@@ -624,20 +806,61 @@ struct XAigerWriter
 			f.write(reinterpret_cast<const char*>(&buffer_size_be), sizeof(buffer_size_be));
 			f.write(buffer_str.data(), buffer_str.size());
 
+			/*if (!ff_bits.empty())*/ {
+				std::stringstream r_buffer;
+				auto write_r_buffer = [&r_buffer](int i32) {
+					// TODO: Don't assume we're on little endian
+#ifdef _WIN32
+					int i32_be = _byteswap_ulong(i32);
+#else
+					int i32_be = __builtin_bswap32(i32);
+#endif
+					r_buffer.write(reinterpret_cast<const char*>(&i32_be), sizeof(i32_be));
+				};
+				log_debug("flopNum = %zu\n", ff_bits.size());
+				write_r_buffer(ff_bits.size());
+				int mergeability_class = 1;
+				for (auto cell : ff_bits)
+					write_r_buffer(mergeability_class++);
+
+				f << "r";
+				std::string buffer_str = r_buffer.str();
+				// TODO: Don't assume we're on little endian
+#ifdef _WIN32
+				int buffer_size_be = _byteswap_ulong(buffer_str.size());
+#else
+				int buffer_size_be = __builtin_bswap32(buffer_str.size());
+#endif
+				f.write(reinterpret_cast<const char*>(&buffer_size_be), sizeof(buffer_size_be));
+				f.write(buffer_str.data(), buffer_str.size());
+			}
+
 			if (holes_module) {
-				holes_module->fixup_ports();
+				// NB: fixup_ports() will sort ports by name
+				//holes_module->fixup_ports();
+				holes_module->check();
 
 				holes_module->design->selection_stack.emplace_back(false);
 				RTLIL::Selection& sel = holes_module->design->selection_stack.back();
 				sel.select(holes_module);
 
-				Pass::call(holes_module->design, "flatten; aigmap");
+				// TODO: Should not need to opt_merge if we only instantiate
+				//       each box type once...
+				Pass::call(holes_module->design, "opt_merge -share_all");
+
+				Pass::call(holes_module->design, "flatten -wb");
+
+				// TODO: Should techmap all lib_whitebox-es once
+				//Pass::call(holes_module->design, "techmap");
+
+				Pass::call(holes_module->design, "aigmap");
+				Pass::call(holes_module->design, "clean -purge");
 
 				holes_module->design->selection_stack.pop_back();
 
 				std::stringstream a_buffer;
-				XAigerWriter writer(holes_module, false /*zinit_mode*/, false /*imode*/, false /*omode*/, false /*bmode*/);
-				writer.write_aiger(a_buffer, false /*ascii_mode*/, false /*miter_mode*/, false /*symbols_mode*/, false /*omode*/);
+				XAigerWriter writer(holes_module, false /*zinit_mode*/, false /*imode*/, false /*omode*/, true /* holes_mode */);
+				writer.write_aiger(a_buffer, false /*ascii_mode*/, false /* omode */);
 
 				f << "a";
 				std::string buffer_str = a_buffer.str();
@@ -675,23 +898,23 @@ struct XAigerWriter
 			{
 				RTLIL::SigBit b(wire, i);
 				if (input_bits.count(b)) {
-					int a = aig_map.at(sig[i]);
+					int a = aig_map.at(b);
 					log_assert((a & 1) == 0);
 					input_lines[a] += stringf("input %d %d %s\n", (a >> 1)-1, i, log_id(wire));
 				}
 
 				if (output_bits.count(b)) {
 					int o = ordered_outputs.at(b);
-					output_lines[o] += stringf("output %d %d %s\n", o, i, log_id(wire));
+					output_lines[o] += stringf("output %lu %d %s\n", o - co_bits.size(), i, log_id(wire));
 					continue;
 				}
 
-				if (init_inputs.count(sig[i])) {
-					int a = init_inputs.at(sig[i]);
-					log_assert((a & 1) == 0);
-					init_lines[a] += stringf("init %d %d %s\n", (a >> 1)-1, i, log_id(wire));
-					continue;
-				}
+				//if (init_inputs.count(sig[i])) {
+				//	int a = init_inputs.at(sig[i]);
+				//	log_assert((a & 1) == 0);
+				//	init_lines[a] += stringf("init %d %d %s\n", (a >> 1)-1, i, log_id(wire));
+				//	continue;
+				//}
 
 				if (ordered_latches.count(sig[i])) {
 					int l = ordered_latches.at(sig[i]);
@@ -712,38 +935,23 @@ struct XAigerWriter
 			}
 		}
 
-		for (const auto &c : ci_bits) {
-			RTLIL::SigBit b = c.first;
-			RTLIL::Wire *wire = b.wire;
-			int i = b.offset;
-			int a = c.second;
-			log_assert((a & 1) == 0);
-			input_lines[a] += stringf("input %d %d %s\n", (a >> 1)-1, i, log_id(wire));
-		}
-
-		for (const auto &c : co_bits) {
-			RTLIL::SigBit b = c.first;
-			RTLIL::Wire *wire = b.wire;
-			int o = c.second;
-			if (wire)
-				output_lines[o] += stringf("output %d %d %s\n", o, b.offset, log_id(wire));
-			else
-				output_lines[o] += stringf("output %d %d __const%d__\n", o, 0, b.data);
-		}
-
 		input_lines.sort();
 		for (auto &it : input_lines)
 			f << it.second;
-		log_assert(input_lines.size() == input_bits.size() + ci_bits.size());
+		log_assert(input_lines.size() == input_bits.size());
 
 		init_lines.sort();
 		for (auto &it : init_lines)
 			f << it.second;
 
+		int box_count = 0;
+		for (auto cell : box_list)
+			f << stringf("box %d %d %s\n", box_count++, 0, log_id(cell->name));
+
 		output_lines.sort();
 		for (auto &it : output_lines)
 			f << it.second;
-		log_assert(output_lines.size() == output_bits.size() + co_bits.size());
+		log_assert(output_lines.size() == output_bits.size());
 		if (omode && output_bits.empty())
 			f << "output " << output_lines.size() << " 0 __dummy_o__\n";
 
@@ -769,15 +977,12 @@ struct XAigerBackend : public Backend {
 		log("all unsupported cells will be converted into psuedo-inputs and pseudo-outputs.\n");
 		log("\n");
 		log("    -ascii\n");
-		log("        write ASCII version of AGIER format\n");
+		log("        write ASCII version of AIGER format\n");
 		log("\n");
 		log("    -zinit\n");
 		log("        convert FFs to zero-initialized FFs, adding additional inputs for\n");
 		log("        uninitialized FFs.\n");
 		log("\n");
-		log("    -symbols\n");
-		log("        include a symbol table in the generated AIGER file\n");
-		log("\n");
 		log("    -map <filename>\n");
 		log("        write an extra file with port and latch symbols\n");
 		log("\n");
@@ -794,12 +999,9 @@ struct XAigerBackend : public Backend {
 	{
 		bool ascii_mode = false;
 		bool zinit_mode = false;
-		bool miter_mode = false;
-		bool symbols_mode = false;
 		bool verbose_map = false;
 		bool imode = false;
 		bool omode = false;
-		bool bmode = false;
 		std::string map_filename;
 
 		log_header(design, "Executing XAIGER backend.\n");
@@ -815,10 +1017,6 @@ struct XAigerBackend : public Backend {
 				zinit_mode = true;
 				continue;
 			}
-			if (args[argidx] == "-symbols") {
-				symbols_mode = true;
-				continue;
-			}
 			if (map_filename.empty() && args[argidx] == "-map" && argidx+1 < args.size()) {
 				map_filename = args[++argidx];
 				continue;
@@ -836,10 +1034,6 @@ struct XAigerBackend : public Backend {
 				omode = true;
 				continue;
 			}
-			if (args[argidx] == "-B") {
-				bmode = true;
-				continue;
-			}
 			break;
 		}
 		extra_args(f, filename, args, argidx);
@@ -849,8 +1043,8 @@ struct XAigerBackend : public Backend {
 		if (top_module == nullptr)
 			log_error("Can't find top module in current design!\n");
 
-		XAigerWriter writer(top_module, zinit_mode, imode, omode, bmode);
-		writer.write_aiger(*f, ascii_mode, miter_mode, symbols_mode, omode);
+		XAigerWriter writer(top_module, zinit_mode, imode, omode);
+		writer.write_aiger(*f, ascii_mode, omode);
 
 		if (!map_filename.empty()) {
 			std::ofstream mapf;