Merge pull request #1619 from YosysHQ/eddie/abc9_refactor

Refactor `abc9` pass

4 files changed, 1480 insertions, 886 deletions

diff --git a/passes/techmap/Makefile.inc b/passes/techmap/Makefile.inc
index cd357d72a..369c9de64 100644
--- a/passes/techmap/Makefile.inc
+++ b/passes/techmap/Makefile.inc
@@ -8,6 +8,8 @@ OBJS += passes/techmap/libparse.o
 ifeq ($(ENABLE_ABC),1)
 OBJS += passes/techmap/abc.o
 OBJS += passes/techmap/abc9.o
+OBJS += passes/techmap/abc9_exe.o
+OBJS += passes/techmap/abc9_ops.o
 ifneq ($(ABCEXTERNAL),)
 passes/techmap/abc.o: CXXFLAGS += -DABCEXTERNAL='"$(ABCEXTERNAL)"'
 passes/techmap/abc9.o: CXXFLAGS += -DABCEXTERNAL='"$(ABCEXTERNAL)"'
diff --git a/passes/techmap/abc9.cc b/passes/techmap/abc9.cc
index 2568a6cd1..2aeda16d6 100644
--- a/passes/techmap/abc9.cc
+++ b/passes/techmap/abc9.cc
@@ -2,7 +2,7 @@
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
- *                2019  Eddie Hung <eddie@fpgeh.com>
+ *            (C) 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
@@ -23,714 +23,19 @@
 // http://www.eecs.berkeley.edu/~alanmi/abc/
 
 #include "kernel/register.h"
-#include "kernel/sigtools.h"
 #include "kernel/celltypes.h"
-#include "kernel/cost.h"
+#include "kernel/rtlil.h"
 #include "kernel/log.h"
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-#include <cerrno>
-#include <sstream>
-#include <climits>
 
-#ifndef _WIN32
-#  include <unistd.h>
-#  include <dirent.h>
-#endif
-
-#include "frontends/aiger/aigerparse.h"
-#include "kernel/utils.h"
-
-#ifdef YOSYS_LINK_ABC
-extern "C" int Abc_RealMain(int argc, char *argv[]);
-#endif
+// abc9_exe.cc
+std::string fold_abc9_cmd(std::string str);
 
 USING_YOSYS_NAMESPACE
 PRIVATE_NAMESPACE_BEGIN
 
-int map_autoidx;
-
-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, RTLIL::Module *module)
-{
-	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
-	// wires
-	pool<RTLIL::Const> ids_seen;
-	for (auto cell : module->cells()) {
-		auto it = cell->attributes.find(ID(abc9_scc_id));
-		if (it != cell->attributes.end()) {
-			auto r = ids_seen.insert(it->second);
-			if (r.second) {
-				for (auto &c : cell->connections_) {
-					if (c.second.is_fully_const()) continue;
-					if (cell->output(c.first)) {
-						SigBit b = c.second.as_bit();
-						Wire *w = b.wire;
-						if (w->port_input) {
-							// In this case, hopefully the loop break has been already created
-							// Get the non-prefixed wire
-							Wire *wo = module->wire(stringf("%s.abco", b.wire->name.c_str()));
-							log_assert(wo != nullptr);
-							log_assert(wo->port_output);
-							log_assert(b.offset < GetSize(wo));
-							c.second = RTLIL::SigBit(wo, b.offset);
-						}
-						else {
-							// Create a new output/input loop break
-							w->port_input = true;
-							w = module->wire(stringf("%s.abco", w->name.c_str()));
-							if (!w) {
-								w = module->addWire(stringf("%s.abco", b.wire->name.c_str()), GetSize(b.wire));
-								w->port_output = true;
-							}
-							else {
-								log_assert(w->port_input);
-								log_assert(b.offset < GetSize(w));
-							}
-							w->set_bool_attribute(ID(abc9_scc_break));
-							c.second = RTLIL::SigBit(w, b.offset);
-						}
-					}
-				}
-			}
-			cell->attributes.erase(it);
-		}
-	}
-
-	module->fixup_ports();
-}
-
-std::string add_echos_to_abc9_cmd(std::string str)
-{
-	std::string new_str, token;
-	for (size_t i = 0; i < str.size(); i++) {
-		token += str[i];
-		if (str[i] == ';') {
-			while (i+1 < str.size() && str[i+1] == ' ')
-				i++;
-			new_str += "echo + " + token + " " + token + " ";
-			token.clear();
-		}
-	}
-
-	if (!token.empty()) {
-		if (!new_str.empty())
-			new_str += "echo + " + token + "; ";
-		new_str += token;
-	}
-
-	return new_str;
-}
-
-std::string fold_abc9_cmd(std::string str)
-{
-	std::string token, new_str = "          ";
-	int char_counter = 10;
-
-	for (size_t i = 0; i <= str.size(); i++) {
-		if (i < str.size())
-			token += str[i];
-		if (i == str.size() || str[i] == ';') {
-			if (char_counter + token.size() > 75)
-				new_str += "\n              ", char_counter = 14;
-			new_str += token, char_counter += token.size();
-			token.clear();
-		}
-	}
-
-	return new_str;
-}
-
-std::string replace_tempdir(std::string text, std::string tempdir_name, bool show_tempdir)
-{
-	if (show_tempdir)
-		return text;
-
-	while (1) {
-		size_t pos = text.find(tempdir_name);
-		if (pos == std::string::npos)
-			break;
-		text = text.substr(0, pos) + "<abc-temp-dir>" + text.substr(pos + GetSize(tempdir_name));
-	}
-
-	std::string  selfdir_name = proc_self_dirname();
-	if (selfdir_name != "/") {
-		while (1) {
-			size_t pos = text.find(selfdir_name);
-			if (pos == std::string::npos)
-				break;
-			text = text.substr(0, pos) + "<yosys-exe-dir>/" + text.substr(pos + GetSize(selfdir_name));
-		}
-	}
-
-	return text;
-}
-
-struct abc9_output_filter
-{
-	bool got_cr;
-	int escape_seq_state;
-	std::string linebuf;
-	std::string tempdir_name;
-	bool show_tempdir;
-
-	abc9_output_filter(std::string tempdir_name, bool show_tempdir) : tempdir_name(tempdir_name), show_tempdir(show_tempdir)
-	{
-		got_cr = false;
-		escape_seq_state = 0;
-	}
-
-	void next_char(char ch)
-	{
-		if (escape_seq_state == 0 && ch == '\033') {
-			escape_seq_state = 1;
-			return;
-		}
-		if (escape_seq_state == 1) {
-			escape_seq_state = ch == '[' ? 2 : 0;
-			return;
-		}
-		if (escape_seq_state == 2) {
-			if ((ch < '0' || '9' < ch) && ch != ';')
-				escape_seq_state = 0;
-			return;
-		}
-		escape_seq_state = 0;
-		if (ch == '\r') {
-			got_cr = true;
-			return;
-		}
-		if (ch == '\n') {
-			log("ABC: %s\n", replace_tempdir(linebuf, tempdir_name, show_tempdir).c_str());
-			got_cr = false, linebuf.clear();
-			return;
-		}
-		if (got_cr)
-			got_cr = false, linebuf.clear();
-		linebuf += ch;
-	}
-
-	void next_line(const std::string &line)
-	{
-		//int pi, po;
-		//if (sscanf(line.c_str(), "Start-point = pi%d.  End-point = po%d.", &pi, &po) == 2) {
-		//	log("ABC: Start-point = pi%d (%s).  End-point = po%d (%s).\n",
-		//			pi, pi_map.count(pi) ? pi_map.at(pi).c_str() : "???",
-		//			po, po_map.count(po) ? po_map.at(po).c_str() : "???");
-		//	return;
-		//}
-
-		for (char ch : line)
-			next_char(ch);
-	}
-};
-
-void abc9_module(RTLIL::Design *design, RTLIL::Module *module, std::string script_file, std::string exe_file,
-		bool cleanup, vector<int> lut_costs, bool dff_mode, std::string delay_target, std::string /*lutin_shared*/, bool fast_mode,
-		bool show_tempdir, std::string box_file, std::string lut_file,
-		std::string wire_delay
-)
+struct Abc9Pass : public ScriptPass
 {
-	map_autoidx = autoidx++;
-
-	std::string tempdir_name = "/tmp/yosys-abc-XXXXXX";
-	if (!cleanup)
-		tempdir_name[0] = tempdir_name[4] = '_';
-	tempdir_name = make_temp_dir(tempdir_name);
-	log_header(design, "Extracting gate netlist of module `%s' to `%s/input.xaig'..\n",
-			module->name.c_str(), replace_tempdir(tempdir_name, tempdir_name, show_tempdir).c_str());
-
-	std::string abc9_script;
-
-	if (!lut_costs.empty()) {
-		abc9_script += stringf("read_lut %s/lutdefs.txt; ", tempdir_name.c_str());
-		if (!box_file.empty())
-			abc9_script += stringf("read_box %s; ", box_file.c_str());
-	}
-	else
-	if (!lut_file.empty()) {
-		abc9_script += stringf("read_lut %s; ", lut_file.c_str());
-		if (!box_file.empty())
-			abc9_script += stringf("read_box %s; ", box_file.c_str());
-	}
-	else
-		log_abort();
-
-	abc9_script += stringf("&read %s/input.xaig; &ps; ", tempdir_name.c_str());
-
-	if (!script_file.empty()) {
-		if (script_file[0] == '+') {
-			for (size_t i = 1; i < script_file.size(); i++)
-				if (script_file[i] == '\'')
-					abc9_script += "'\\''";
-				else if (script_file[i] == ',')
-					abc9_script += " ";
-				else
-					abc9_script += script_file[i];
-		} else
-			abc9_script += stringf("source %s", script_file.c_str());
-	} else if (!lut_costs.empty() || !lut_file.empty()) {
-		abc9_script += fast_mode ? RTLIL::constpad.at("abc9.script.default.fast").substr(1,std::string::npos)
-			: RTLIL::constpad.at("abc9.script.default").substr(1,std::string::npos);
-	} else
-		log_abort();
-
-	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);
-
-	//for (size_t pos = abc9_script.find("{S}"); pos != std::string::npos; pos = abc9_script.find("{S}", pos))
-	//	abc9_script = abc9_script.substr(0, pos) + lutin_shared + abc9_script.substr(pos+3);
-
-	for (size_t pos = abc9_script.find("{W}"); pos != std::string::npos; pos = abc9_script.find("{W}", pos))
-		abc9_script = abc9_script.substr(0, pos) + wire_delay + abc9_script.substr(pos+3);
-
-	std::string C;
-	if (design->scratchpad.count("abc9.if.C"))
-		C = "-C " + design->scratchpad_get_string("abc9.if.C");
-	for (size_t pos = abc9_script.find("{C}"); pos != std::string::npos; pos = abc9_script.find("{C}", pos))
-		abc9_script = abc9_script.substr(0, pos) + C + abc9_script.substr(pos+3);
-
-	std::string R;
-	if (design->scratchpad.count("abc9.if.R"))
-		R = "-R " + design->scratchpad_get_string("abc9.if.R");
-	for (size_t pos = abc9_script.find("{R}"); pos != std::string::npos; pos = abc9_script.find("{R}", pos))
-		abc9_script = abc9_script.substr(0, pos) + R + abc9_script.substr(pos+3);
-
-	abc9_script += stringf("; &ps -l; &write -n %s/output.aig", tempdir_name.c_str());
-	if (design->scratchpad_get_bool("abc9.verify")) {
-		if (dff_mode)
-			abc9_script += "; &verify -s";
-		else
-			abc9_script += "; &verify";
-	}
-	abc9_script += "; time";
-	abc9_script = add_echos_to_abc9_cmd(abc9_script);
-
-	for (size_t i = 0; i+1 < abc9_script.size(); i++)
-		if (abc9_script[i] == ';' && abc9_script[i+1] == ' ')
-			abc9_script[i+1] = '\n';
-
-	FILE *f = fopen(stringf("%s/abc.script", tempdir_name.c_str()).c_str(), "wt");
-	fprintf(f, "%s\n", abc9_script.c_str());
-	fclose(f);
-
-	log_push();
-
-	handle_loops(design, module);
-
-	Pass::call(design, "aigmap -select");
-
-	Pass::call(design, stringf("write_xaiger -map %s/input.sym %s/input.xaig", tempdir_name.c_str(), tempdir_name.c_str()));
-
-	int count_outputs = design->scratchpad_get_int("write_xaiger.num_outputs");
-	log("Extracted %d AND gates and %d wires to a netlist network with %d inputs and %d outputs.\n",
-			design->scratchpad_get_int("write_xaiger.num_ands"),
-			design->scratchpad_get_int("write_xaiger.num_wires"),
-			design->scratchpad_get_int("write_xaiger.num_inputs"),
-			count_outputs);
-
-	if (count_outputs > 0) {
-		std::string buffer;
-		std::ifstream ifs;
-#if 0
-		buffer = stringf("%s/%s", tempdir_name.c_str(), "input.xaig");
-		ifs.open(buffer);
-		if (ifs.fail())
-			log_error("Can't open ABC output file `%s'.\n", buffer.c_str());
-		buffer = stringf("%s/%s", tempdir_name.c_str(), "input.sym");
-		log_assert(!design->module(ID($__abc9__)));
-		{
-			AigerReader reader(design, ifs, ID($__abc9__), "" /* clk_name */, buffer.c_str() /* map_filename */, true /* wideports */);
-			reader.parse_xaiger();
-		}
-		ifs.close();
-		Pass::call_on_module(design, design->module(ID($__abc9__)), stringf("write_verilog -noexpr -norename -selected"));
-		design->remove(design->module(ID($__abc9__)));
-#endif
-
-		log_header(design, "Executing ABC9.\n");
-
-		if (!lut_costs.empty()) {
-			buffer = stringf("%s/lutdefs.txt", tempdir_name.c_str());
-			f = fopen(buffer.c_str(), "wt");
-			if (f == NULL)
-				log_error("Opening %s for writing failed: %s\n", buffer.c_str(), strerror(errno));
-			for (int i = 0; i < GetSize(lut_costs); i++)
-				fprintf(f, "%d %d.00 1.00\n", i+1, lut_costs.at(i));
-			fclose(f);
-		}
-
-		buffer = stringf("%s -s -f %s/abc.script 2>&1", exe_file.c_str(), tempdir_name.c_str());
-		log("Running ABC command: %s\n", replace_tempdir(buffer, tempdir_name, show_tempdir).c_str());
-
-#ifndef YOSYS_LINK_ABC
-		abc9_output_filter filt(tempdir_name, show_tempdir);
-		int ret = run_command(buffer, std::bind(&abc9_output_filter::next_line, filt, std::placeholders::_1));
-#else
-		// These needs to be mutable, supposedly due to getopt
-		char *abc9_argv[5];
-		string tmp_script_name = stringf("%s/abc.script", tempdir_name.c_str());
-		abc9_argv[0] = strdup(exe_file.c_str());
-		abc9_argv[1] = strdup("-s");
-		abc9_argv[2] = strdup("-f");
-		abc9_argv[3] = strdup(tmp_script_name.c_str());
-		abc9_argv[4] = 0;
-		int ret = Abc_RealMain(4, abc9_argv);
-		free(abc9_argv[0]);
-		free(abc9_argv[1]);
-		free(abc9_argv[2]);
-		free(abc9_argv[3]);
-#endif
-		if (ret != 0)
-			log_error("ABC: execution of command \"%s\" failed: return code %d.\n", buffer.c_str(), ret);
-
-		buffer = stringf("%s/%s", tempdir_name.c_str(), "output.aig");
-		ifs.open(buffer, std::ifstream::binary);
-		if (ifs.fail())
-			log_error("Can't open ABC output file `%s'.\n", buffer.c_str());
-
-		buffer = stringf("%s/%s", tempdir_name.c_str(), "input.sym");
-		log_assert(!design->module(ID($__abc9__)));
-
-		AigerReader reader(design, ifs, ID($__abc9__), "" /* clk_name */, buffer.c_str() /* map_filename */, true /* wideports */);
-		reader.parse_xaiger();
-		ifs.close();
-
-#if 0
-		Pass::call_on_module(design, design->module(ID($__abc9__)), stringf("write_verilog -noexpr -norename -selected"));
-#endif
-
-		log_header(design, "Re-integrating ABC9 results.\n");
-		RTLIL::Module *mapped_mod = design->module(ID($__abc9__));
-		if (mapped_mod == NULL)
-			log_error("ABC output file does not contain a module `$__abc9__'.\n");
-
-		for (auto w : mapped_mod->wires())
-			module->addWire(remap_name(w->name), GetSize(w));
-
-		dict<IdString, bool> abc9_box;
-		vector<RTLIL::Cell*> boxes;
-		for (auto cell : module->cells().to_vector()) {
-			if (cell->type.in(ID($_AND_), ID($_NOT_), ID($__ABC9_FF_))) {
-				module->remove(cell);
-				continue;
-			}
-			RTLIL::Module* box_module = design->module(cell->type);
-			auto jt = abc9_box.find(cell->type);
-			if (jt == abc9_box.end())
-				jt = abc9_box.insert(std::make_pair(cell->type, box_module && box_module->attributes.count(ID(abc9_box_id)))).first;
-			if (jt->second) {
-				if (box_module->get_bool_attribute("\\abc9_flop")) {
-					if (dff_mode)
-						boxes.emplace_back(cell);
-					else
-						box_module->set_bool_attribute("\\abc9_keep", false);
-				}
-				else
-					boxes.emplace_back(cell);
-			}
-		}
-
-		dict<SigBit, pool<IdString>> bit_drivers, bit_users;
-		TopoSort<IdString, RTLIL::sort_by_id_str> toposort;
-		dict<RTLIL::Cell*,RTLIL::Cell*> not2drivers;
-		dict<SigBit, std::vector<RTLIL::Cell*>> bit2sinks;
-
-		std::map<IdString, int> cell_stats;
-		for (auto mapped_cell : mapped_mod->cells())
-		{
-			toposort.node(mapped_cell->name);
-
-			RTLIL::Cell *cell = nullptr;
-			if (mapped_cell->type == ID($_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) {
-					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);
-				}
-				else if (!lut_costs.empty() || !lut_file.empty()) {
-					RTLIL::Cell* driver_lut = nullptr;
-					// ABC can return NOT gates that drive POs
-					if (!a_bit.wire->port_input) {
-						// If it's not a NOT gate that that comes from a PI directly,
-						// find the driver LUT and clone that to guarantee that we won't
-						// increase the max logic depth
-						// (TODO: Optimise by not cloning unless will increase depth)
-						RTLIL::IdString driver_name;
-						if (GetSize(a_bit.wire) == 1)
-							driver_name = stringf("$lut%s", a_bit.wire->name.c_str());
-						else
-							driver_name = stringf("$lut%s[%d]", a_bit.wire->name.c_str(), a_bit.offset);
-						driver_lut = mapped_mod->cell(driver_name);
-					}
-
-					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("$lut%s", mapped_cell->name.c_str())),
-								RTLIL::SigBit(module->wires_.at(remap_name(a_bit.wire->name)), a_bit.offset),
-								RTLIL::SigBit(module->wires_.at(remap_name(y_bit.wire->name)), y_bit.offset),
-								RTLIL::Const::from_string("01"));
-						bit2sinks[cell->getPort(ID::A)].push_back(cell);
-						cell_stats[ID($lut)]++;
-					}
-					else
-						not2drivers[mapped_cell] = driver_lut;
-					continue;
-				}
-				else
-					log_abort();
-				continue;
-			}
-			cell_stats[mapped_cell->type]++;
-
-			RTLIL::Cell *existing_cell = nullptr;
-			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);
-					log_abort();
-					continue;
-				}
-				cell = module->addCell(remap_name(mapped_cell->name), mapped_cell->type);
-			}
-			else {
-				existing_cell = module->cell(mapped_cell->name);
-				log_assert(existing_cell);
-				cell = module->addCell(remap_name(mapped_cell->name), mapped_cell->type);
-			}
-
-			if (existing_cell) {
-				cell->parameters = existing_cell->parameters;
-				cell->attributes = existing_cell->attributes;
-			}
-			else {
-				cell->parameters = mapped_cell->parameters;
-				cell->attributes = mapped_cell->attributes;
-			}
-
-			RTLIL::Module* box_module = design->module(mapped_cell->type);
-			auto abc9_flop = box_module && box_module->get_bool_attribute("\\abc9_flop");
-			for (auto &conn : mapped_cell->connections()) {
-				RTLIL::SigSpec newsig;
-				for (auto c : conn.second.chunks()) {
-					if (c.width == 0)
-						continue;
-					//log_assert(c.width == 1);
-					if (c.wire)
-						c.wire = module->wires_.at(remap_name(c.wire->name));
-					newsig.append(c);
-				}
-				cell->setPort(conn.first, newsig);
-
-				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);
-				}
-			}
-		}
-
-		for (auto existing_cell : boxes) {
-			Cell *cell = module->cell(remap_name(existing_cell->name));
-			if (cell) {
-				for (auto &conn : existing_cell->connections()) {
-					if (!conn.second.is_wire())
-						continue;
-					Wire *wire = conn.second.as_wire();
-					if (!wire->get_bool_attribute(ID(abc9_padding)))
-						continue;
-					cell->unsetPort(conn.first);
-					log_debug("Dropping padded port connection for %s (%s) .%s (%s )\n", log_id(cell), cell->type.c_str(), log_id(conn.first), log_signal(conn.second));
-				}
-				module->swap_names(cell, existing_cell);
-			}
-			module->remove(existing_cell);
-		}
-
-		// Copy connections (and rename) from mapped_mod to module
-		for (auto conn : mapped_mod->connections()) {
-			if (!conn.first.is_fully_const()) {
-				auto chunks = conn.first.chunks();
-				for (auto &c : chunks)
-					c.wire = module->wires_.at(remap_name(c.wire->name));
-				conn.first = std::move(chunks);
-			}
-			if (!conn.second.is_fully_const()) {
-				auto chunks = conn.second.chunks();
-				for (auto &c : chunks)
-					if (c.wire)
-						c.wire = module->wires_.at(remap_name(c.wire->name));
-				conn.second = std::move(chunks);
-			}
-			module->connect(conn);
-		}
-
-		for (auto &it : cell_stats)
-			log("ABC RESULTS:   %15s cells: %8d\n", it.first.c_str(), it.second);
-		int in_wires = 0, out_wires = 0;
-
-		// Stitch in mapped_mod's inputs/outputs into module
-		for (auto port : mapped_mod->ports) {
-			RTLIL::Wire *w = mapped_mod->wire(port);
-			RTLIL::Wire *wire = module->wire(port);
-			log_assert(wire);
-			RTLIL::Wire *remap_wire = module->wire(remap_name(port));
-			RTLIL::SigSpec signal = RTLIL::SigSpec(wire, 0, GetSize(remap_wire));
-			log_assert(GetSize(signal) >= GetSize(remap_wire));
-
-			RTLIL::SigSig conn;
-			if (w->port_output) {
-				conn.first = signal;
-				conn.second = remap_wire;
-				out_wires++;
-				module->connect(conn);
-			}
-			else if (w->port_input) {
-				conn.first = remap_wire;
-				conn.second = signal;
-				in_wires++;
-				module->connect(conn);
-			}
-		}
-
-		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);
-		bool no_loops YS_ATTRIBUTE(unused) = toposort.sort();
-		log_assert(no_loops);
-
-		for (auto ii = toposort.sorted.rbegin(); ii != toposort.sorted.rend(); ii++) {
-			RTLIL::Cell *not_cell = mapped_mod->cell(*ii);
-			log_assert(not_cell);
-			if (not_cell->type != ID($_NOT_))
-				continue;
-			auto it = not2drivers.find(not_cell);
-			if (it == not2drivers.end())
-				continue;
-			RTLIL::Cell *driver_lut = it->second;
-			RTLIL::SigBit a_bit = not_cell->getPort(ID::A);
-			RTLIL::SigBit y_bit = not_cell->getPort(ID::Y);
-			RTLIL::Const driver_mask;
-
-			a_bit.wire = module->wires_.at(remap_name(a_bit.wire->name));
-			y_bit.wire = module->wires_.at(remap_name(y_bit.wire->name));
-
-			auto jt = bit2sinks.find(a_bit);
-			if (jt == bit2sinks.end())
-				goto clone_lut;
-
-			for (auto sink_cell : jt->second)
-				if (sink_cell->type != ID($lut))
-					goto clone_lut;
-
-			// Push downstream LUTs past inverter
-			for (auto sink_cell : jt->second) {
-				SigSpec A = sink_cell->getPort(ID::A);
-				RTLIL::Const mask = sink_cell->getParam(ID(LUT));
-				int index = 0;
-				for (; index < GetSize(A); index++)
-					if (A[index] == a_bit)
-						break;
-				log_assert(index < GetSize(A));
-				int i = 0;
-				while (i < GetSize(mask)) {
-					for (int j = 0; j < (1 << index); j++)
-						std::swap(mask[i+j], mask[i+j+(1 << index)]);
-					i += 1 << (index+1);
-				}
-				A[index] = y_bit;
-				sink_cell->setPort(ID::A, A);
-				sink_cell->setParam(ID(LUT), mask);
-			}
-
-			// Since we have rewritten all sinks (which we know
-			// to be only LUTs) to be after the inverter, we can
-			// go ahead and clone the LUT with the expectation
-			// that the original driving LUT will become dangling
-			// and get cleaned away
-clone_lut:
-			driver_mask = driver_lut->getParam(ID(LUT));
-			for (auto &b : driver_mask.bits) {
-				if (b == RTLIL::State::S0) b = RTLIL::State::S1;
-				else if (b == RTLIL::State::S1) b = RTLIL::State::S0;
-			}
-			auto cell = module->addLut(NEW_ID,
-					driver_lut->getPort(ID::A),
-					y_bit,
-					driver_mask);
-			for (auto &bit : cell->connections_.at(ID::A)) {
-				bit.wire = module->wires_.at(remap_name(bit.wire->name));
-				bit2sinks[bit].push_back(cell);
-			}
-		}
-
-		// Now 'unexpose' those wires by undoing
-		// the expose operation -- remove them from PO/PI
-		// and re-connecting them back together
-		for (auto wire : module->wires()) {
-			auto it = wire->attributes.find(ID(abc9_scc_break));
-			if (it != wire->attributes.end()) {
-				wire->attributes.erase(it);
-				log_assert(wire->port_output);
-				wire->port_output = false;
-				std::string name = wire->name.str();
-				RTLIL::Wire *i_wire = module->wire(name.substr(0, GetSize(name) - 5));
-				log_assert(i_wire);
-				log_assert(i_wire->port_input);
-				i_wire->port_input = false;
-				module->connect(i_wire, wire);
-			}
-		}
-		module->fixup_ports();
-
-		//log("ABC RESULTS:        internal signals: %8d\n", int(signal_list.size()) - in_wires - out_wires);
-		log("ABC RESULTS:           input signals: %8d\n", in_wires);
-		log("ABC RESULTS:          output signals: %8d\n", out_wires);
-
-		design->remove(mapped_mod);
-	}
-	else
-	{
-		log("Don't call ABC as there is nothing to map.\n");
-	}
-
-	if (cleanup)
-	{
-		log("Removing temp directory.\n");
-		remove_directory(tempdir_name);
-	}
-
-	log_pop();
-}
-
-struct Abc9Pass : public Pass {
-	Abc9Pass() : Pass("abc9", "use ABC9 for technology mapping") { }
+	Abc9Pass() : ScriptPass("abc9", "use ABC9 for technology mapping") { }
 	void on_register() YS_OVERRIDE
 	{
 		RTLIL::constpad["abc9.script.default"] = "+&scorr; &sweep; &dc2; &dch -f; &ps; &if {C} {W} {D} {R} -v; &mfs";
@@ -782,8 +87,14 @@ struct Abc9Pass : public Pass {
 		log("\n");
 		log("    abc9 [options] [selection]\n");
 		log("\n");
-		log("This pass uses the ABC tool [1] for technology mapping of yosys's internal gate\n");
-		log("library to a target architecture. Only fully-selected modules are supported.\n");
+		log("This script pass performs a sequence of commands to facilitate the use of the ABC\n");
+		log("tool [1] for technology mapping of the current design to a target FPGA\n");
+		log("architecture. Only fully-selected modules are supported.\n");
+		log("\n");
+		log("    -run <from_label>:<to_label>\n");
+		log("        only run the commands between the labels (see below). an empty\n");
+		log("        from label is synonymous to 'begin', and empty to label is\n");
+		log("        synonymous to the end of the command list.\n");
 		log("\n");
 		log("    -exe <command>\n");
 #ifdef ABCEXTERNAL
@@ -802,15 +113,11 @@ struct Abc9Pass : public Pass {
 		log("        replaced with blanks before the string is passed to ABC.\n");
 		log("\n");
 		log("        if no -script parameter is given, the following scripts are used:\n");
-		log("\n");
-		log("        for -lut/-luts:\n");
 		log("%s\n", fold_abc9_cmd(RTLIL::constpad.at("abc9.script.default").substr(1,std::string::npos)).c_str());
 		log("\n");
 		log("    -fast\n");
 		log("        use different default scripts that are slightly faster (at the cost\n");
 		log("        of output quality):\n");
-		log("\n");
-		log("        for -lut/-luts:\n");
 		log("%s\n", fold_abc9_cmd(RTLIL::constpad.at("abc9.script.default.fast").substr(1,std::string::npos)).c_str());
 		log("\n");
 		log("    -D <picoseconds>\n");
@@ -851,7 +158,7 @@ struct Abc9Pass : public Pass {
 		log("        command output is identical across runs.\n");
 		log("\n");
 		log("    -box <file>\n");
-		log("        pass this file with box library to ABC. Use with -lut.\n");
+		log("        pass this file with box library to ABC.\n");
 		log("\n");
 		log("Note that this is a logic optimization pass within Yosys that is calling ABC\n");
 		log("internally. This is not going to \"run ABC on your design\". It will instead run\n");
@@ -862,234 +169,163 @@ struct Abc9Pass : public Pass {
 		log("\n");
 		log("[1] http://www.eecs.berkeley.edu/~alanmi/abc/\n");
 		log("\n");
+		help_script();
+		log("\n");
 	}
-	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
-	{
-		log_header(design, "Executing ABC9 pass (technology mapping using ABC9).\n");
-		log_push();
 
-#ifdef ABCEXTERNAL
-		std::string exe_file = ABCEXTERNAL;
-#else
-		std::string exe_file = proc_self_dirname() + "yosys-abc";
-#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, cleanup = true;
-		bool show_tempdir = false;
-		vector<int> lut_costs;
+	std::stringstream exe_cmd;
+	bool dff_mode, cleanup;
 
-#if 0
-		cleanup = false;
-		show_tempdir = true;
-#endif
+	void clear_flags() YS_OVERRIDE
+	{
+		exe_cmd.str("");
+		exe_cmd << "abc9_exe";
+		dff_mode = false;
+		cleanup = true;
+	}
 
-#ifdef _WIN32
-#ifndef ABCEXTERNAL
-		if (!check_file_exists(exe_file + ".exe") && check_file_exists(proc_self_dirname() + "..\\yosys-abc.exe"))
-			exe_file = proc_self_dirname() + "..\\yosys-abc";
-#endif
-#endif
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		std::string run_from, run_to;
+		clear_flags();
 
 		// get arguments from scratchpad first, then override by command arguments
-		std::string lut_arg, luts_arg;
-		exe_file = design->scratchpad_get_string("abc9.exe", exe_file /* inherit default value if not set */);
-		script_file = design->scratchpad_get_string("abc9.script", script_file);
-		if (design->scratchpad.count("abc9.D")) {
-			delay_target = "-D " + design->scratchpad_get_string("abc9.D");
-		}
-		lut_arg = design->scratchpad_get_string("abc9.lut", lut_arg);
-		luts_arg = design->scratchpad_get_string("abc9.luts", luts_arg);
-		fast_mode = design->scratchpad_get_bool("abc9.fast", fast_mode);
 		dff_mode = design->scratchpad_get_bool("abc9.dff", dff_mode);
 		cleanup = !design->scratchpad_get_bool("abc9.nocleanup", !cleanup);
-		show_tempdir = design->scratchpad_get_bool("abc9.showtmp", show_tempdir);
-		box_file = design->scratchpad_get_string("abc9.box", box_file);
-		if (design->scratchpad.count("abc9.W")) {
-			wire_delay = "-W " + design->scratchpad_get_string("abc9.W");
-		}
 
 		if (design->scratchpad_get_bool("abc9.debug")) {
 			cleanup = false;
-			show_tempdir = true;
+			exe_cmd << " -showtmp";
 		}
 
 		size_t argidx;
-		char pwd [PATH_MAX];
-		if (!getcwd(pwd, sizeof(pwd))) {
-			log_cmd_error("getcwd failed: %s\n", strerror(errno));
-			log_abort();
-		}
 		for (argidx = 1; argidx < args.size(); argidx++) {
 			std::string arg = args[argidx];
-			if (arg == "-exe" && argidx+1 < args.size()) {
-				exe_file = args[++argidx];
-				continue;
-			}
-			if (arg == "-script" && argidx+1 < args.size()) {
-				script_file = args[++argidx];
-				continue;
-			}
-			if (arg == "-D" && argidx+1 < args.size()) {
-				delay_target = "-D " + args[++argidx];
-				continue;
-			}
-			//if (arg == "-S" && argidx+1 < args.size()) {
-			//	lutin_shared = "-S " + args[++argidx];
-			//	continue;
-			//}
-			if (arg == "-lut" && argidx+1 < args.size()) {
-				lut_arg = args[++argidx];
+			if ((arg == "-exe" || arg == "-script" || arg == "-D" ||
+						/* arg == "-S" || */ arg == "-lut" || arg == "-luts" ||
+						arg == "-box" || arg == "-W") &&
+					argidx+1 < args.size()) {
+				exe_cmd << " " << arg << " " << args[++argidx];
 				continue;
 			}
-			if (arg == "-luts" && argidx+1 < args.size()) {
-				luts_arg = args[++argidx];
-				continue;
-			}
-			if (arg == "-fast") {
-				fast_mode = true;
+			if (arg == "-fast" || /* arg == "-dff" || */
+					/* arg == "-nocleanup" || */ arg == "-showtmp") {
+				exe_cmd << " " << arg;
 				continue;
 			}
 			if (arg == "-dff") {
 				dff_mode = true;
+				exe_cmd << " " << arg;
 				continue;
 			}
 			if (arg == "-nocleanup") {
 				cleanup = false;
 				continue;
 			}
-			if (arg == "-showtmp") {
-				show_tempdir = true;
-				continue;
-			}
-			if (arg == "-box" && argidx+1 < args.size()) {
-				box_file = args[++argidx];
-				continue;
-			}
-			if (arg == "-W" && argidx+1 < args.size()) {
-				wire_delay = "-W " + args[++argidx];
+			if (arg == "-run" && argidx+1 < args.size()) {
+				size_t pos = args[argidx+1].find(':');
+				if (pos == std::string::npos)
+					break;
+				run_from = args[++argidx].substr(0, pos);
+				run_to = args[argidx].substr(pos+1);
 				continue;
 			}
 			break;
 		}
 		extra_args(args, argidx, design);
 
-		rewrite_filename(script_file);
-		if (!script_file.empty() && !is_absolute_path(script_file) && script_file[0] != '+')
-			script_file = std::string(pwd) + "/" + script_file;
-
-		// handle -lut / -luts args
-		if (!lut_arg.empty()) {
-			string arg = lut_arg;
-			if (arg.find_first_not_of("0123456789:") == std::string::npos) {
-				size_t pos = arg.find_first_of(':');
-				int lut_mode = 0, lut_mode2 = 0;
-				if (pos != string::npos) {
-					lut_mode = atoi(arg.substr(0, pos).c_str());
-					lut_mode2 = atoi(arg.substr(pos+1).c_str());
-				} else {
-					lut_mode = atoi(arg.c_str());
-					lut_mode2 = lut_mode;
-				}
-				lut_costs.clear();
-				for (int i = 0; i < lut_mode; i++)
-					lut_costs.push_back(1);
-				for (int i = lut_mode; i < lut_mode2; i++)
-					lut_costs.push_back(2 << (i - lut_mode));
-			}
-			else {
-				lut_file = arg;
-				rewrite_filename(lut_file);
-				if (!lut_file.empty() && !is_absolute_path(lut_file) && lut_file[0] != '+')
-					lut_file = std::string(pwd) + "/" + lut_file;
-			}
-		}
-		if (!luts_arg.empty()) {
-			lut_costs.clear();
-			for (auto &tok : split_tokens(luts_arg, ",")) {
-				auto parts = split_tokens(tok, ":");
-				if (GetSize(parts) == 0 && !lut_costs.empty())
-					lut_costs.push_back(lut_costs.back());
-				else if (GetSize(parts) == 1)
-					lut_costs.push_back(atoi(parts.at(0).c_str()));
-				else if (GetSize(parts) == 2)
-					while (GetSize(lut_costs) < atoi(parts.at(0).c_str()))
-						lut_costs.push_back(atoi(parts.at(1).c_str()));
-				else
-					log_cmd_error("Invalid -luts syntax.\n");
-			}
+		log_assert(design);
+		if (design->selected_modules().empty()) {
+			log_warning("No modules selected for ABC9 techmapping.\n");
+			return;
 		}
 
-		// ABC expects a box file for XAIG
-		if (box_file.empty())
-		    box_file = "+/dummy.box";
+		log_header(design, "Executing ABC9 pass.\n");
+		log_push();
 
-		rewrite_filename(box_file);
-		if (!box_file.empty() && !is_absolute_path(box_file) && box_file[0] != '+')
-		    box_file = std::string(pwd) + "/" + box_file;
+		run_script(design, run_from, run_to);
 
-		SigMap assign_map;
-		CellTypes ct(design);
-		for (auto module : design->selected_modules())
-		{
-			if (module->processes.size() > 0) {
-				log("Skipping module %s as it contains processes.\n", log_id(module));
-				continue;
+		log_pop();
+	}
+
+	void script() YS_OVERRIDE
+	{
+		if (check_label("pre")) {
+			run("scc -set_attr abc9_scc_id {}");
+			if (help_mode)
+				run("abc9_ops -mark_scc -prep_xaiger [-dff]", "(option for -dff)");
+			else
+				run("abc9_ops -mark_scc -prep_xaiger" + std::string(dff_mode ? " -dff" : ""), "(option for -dff)");
+			run("select -set abc9_holes A:abc9_holes");
+			run("flatten -wb @abc9_holes");
+			run("techmap @abc9_holes");
+			if (dff_mode || help_mode)
+				run("abc9_ops -prep_dff", "(only if -dff)");
+			run("opt -purge @abc9_holes");
+			run("aigmap");
+			run("wbflip @abc9_holes");
+		}
+
+		if (check_label("map")) {
+			if (help_mode) {
+				run("foreach module in selection");
+				run("    write_xaiger -map <abc-temp-dir>/input.sym <abc-temp-dir>/input.xaig");
+				run("    abc9_exe -cwd <abc-temp-dir> [options]");
+				run("    read_aiger -xaiger -wideports -module_name <module-name>$abc9 -map <abc-temp-dir>/input.sym <abc-temp-dir>/output.aig");
+				run("    abc9_ops -reintegrate");
 			}
-			log_assert(!module->attributes.count(ID(abc9_box_id)));
+			else {
+				auto selected_modules = active_design->selected_modules();
+				active_design->selection_stack.emplace_back(false);
 
-			if (!design->selected_whole_module(module))
-				log_error("Can't handle partially selected module %s!\n", log_id(module));
+				for (auto mod : selected_modules) {
+					if (mod->processes.size() > 0) {
+						log("Skipping module %s as it contains processes.\n", log_id(mod));
+						continue;
+					}
+					log_assert(!mod->attributes.count(ID(abc9_box_id)));
 
-			assign_map.set(module);
+					log_push();
+					active_design->selection().select(mod);
 
-			typedef SigSpec clkdomain_t;
-			dict<clkdomain_t, int> clk_to_mergeability;
+					if (!active_design->selected_whole_module(mod))
+						log_error("Can't handle partially selected module %s!\n", log_id(mod));
 
-			if (dff_mode)
-				for (auto cell : module->cells()) {
-					if (cell->type != "$__ABC9_FF_")
-						continue;
+					std::string tempdir_name = "/tmp/yosys-abc-XXXXXX";
+					if (!cleanup)
+						tempdir_name[0] = tempdir_name[4] = '_';
+					tempdir_name = make_temp_dir(tempdir_name);
 
-					Wire *abc9_clock_wire = module->wire(stringf("%s.clock", cell->name.c_str()));
-					if (abc9_clock_wire == NULL)
-						log_error("'%s.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);
+					run(stringf("write_xaiger -map %s/input.sym %s/input.xaig", tempdir_name.c_str(), tempdir_name.c_str()));
 
-					clkdomain_t key(abc9_clock);
+					int num_outputs = active_design->scratchpad_get_int("write_xaiger.num_outputs");
 
-					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);
+					log("Extracted %d AND gates and %d wires from module `%s' to a netlist network with %d inputs and %d outputs.\n",
+							active_design->scratchpad_get_int("write_xaiger.num_ands"),
+							active_design->scratchpad_get_int("write_xaiger.num_wires"),
+							log_id(mod),
+							active_design->scratchpad_get_int("write_xaiger.num_inputs"),
+							num_outputs);
+					if (num_outputs) {
+						run(stringf("%s -cwd %s", exe_cmd.str().c_str(), tempdir_name.c_str()));
+						run(stringf("read_aiger -xaiger -wideports -module_name %s$abc9 -map %s/input.sym %s/output.aig", log_id(mod), tempdir_name.c_str(), tempdir_name.c_str()));
+						run("abc9_ops -reintegrate");
+					}
+					else
+						log("Don't call ABC as there is nothing to map.\n");
 
-					Wire *abc9_init_wire = module->wire(stringf("%s.init", cell->name.c_str()));
-					if (abc9_init_wire == NULL)
-						log_error("'%s.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.init' is not a constant wire present in module '%s'.\n", cell->name.c_str(), log_id(module));
-					if (abc9_init == State::S1)
-						log_error("'%s.init' in module '%s' has value 1'b1 which is not supported by 'abc9 -dff'.\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);
-				}
-			else
-				for (auto cell : module->cells()) {
-					auto inst_module = design->module(cell->type);
-					if (!inst_module || !inst_module->get_bool_attribute("\\abc9_flop"))
-						continue;
-					cell->set_bool_attribute("\\abc9_keep");
+					if (cleanup) {
+						log("Removing temp directory.\n");
+						remove_directory(tempdir_name);
+					}
+
+					active_design->selection().selected_modules.clear();
+					log_pop();
 				}
 
-			design->selected_active_module = module->name.str();
-			abc9_module(design, module, script_file, exe_file, cleanup, lut_costs, dff_mode,
-					delay_target, lutin_shared, fast_mode, show_tempdir,
-					box_file, lut_file, wire_delay);
-			design->selected_active_module.clear();
+				active_design->selection_stack.pop_back();
+			}
 		}
-
-		log_pop();
 	}
 } Abc9Pass;
 
diff --git a/passes/techmap/abc9_exe.cc b/passes/techmap/abc9_exe.cc
new file mode 100644
index 000000000..01bf46539
--- /dev/null
+++ b/passes/techmap/abc9_exe.cc
@@ -0,0 +1,531 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *                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
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+// [[CITE]] ABC
+// Berkeley Logic Synthesis and Verification Group, ABC: A System for Sequential Synthesis and Verification
+// http://www.eecs.berkeley.edu/~alanmi/abc/
+
+#include "kernel/register.h"
+#include "kernel/log.h"
+
+#ifndef _WIN32
+#  include <unistd.h>
+#  include <dirent.h>
+#endif
+
+#ifdef YOSYS_LINK_ABC
+extern "C" int Abc_RealMain(int argc, char *argv[]);
+#endif
+
+std::string fold_abc9_cmd(std::string str)
+{
+	std::string token, new_str = "          ";
+	int char_counter = 10;
+
+	for (size_t i = 0; i <= str.size(); i++) {
+		if (i < str.size())
+			token += str[i];
+		if (i == str.size() || str[i] == ';') {
+			if (char_counter + token.size() > 75)
+				new_str += "\n              ", char_counter = 14;
+			new_str += token, char_counter += token.size();
+			token.clear();
+		}
+	}
+
+	return new_str;
+}
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+std::string add_echos_to_abc9_cmd(std::string str)
+{
+	std::string new_str, token;
+	for (size_t i = 0; i < str.size(); i++) {
+		token += str[i];
+		if (str[i] == ';') {
+			while (i+1 < str.size() && str[i+1] == ' ')
+				i++;
+			new_str += "echo + " + token + " " + token + " ";
+			token.clear();
+		}
+	}
+
+	if (!token.empty()) {
+		if (!new_str.empty())
+			new_str += "echo + " + token + "; ";
+		new_str += token;
+	}
+
+	return new_str;
+}
+
+std::string replace_tempdir(std::string text, std::string tempdir_name, bool show_tempdir)
+{
+	if (show_tempdir)
+		return text;
+
+	while (1) {
+		size_t pos = text.find(tempdir_name);
+		if (pos == std::string::npos)
+			break;
+		text = text.substr(0, pos) + "<abc-temp-dir>" + text.substr(pos + GetSize(tempdir_name));
+	}
+
+	std::string  selfdir_name = proc_self_dirname();
+	if (selfdir_name != "/") {
+		while (1) {
+			size_t pos = text.find(selfdir_name);
+			if (pos == std::string::npos)
+				break;
+			text = text.substr(0, pos) + "<yosys-exe-dir>/" + text.substr(pos + GetSize(selfdir_name));
+		}
+	}
+
+	return text;
+}
+
+struct abc9_output_filter
+{
+	bool got_cr;
+	int escape_seq_state;
+	std::string linebuf;
+	std::string tempdir_name;
+	bool show_tempdir;
+
+	abc9_output_filter(std::string tempdir_name, bool show_tempdir) : tempdir_name(tempdir_name), show_tempdir(show_tempdir)
+	{
+		got_cr = false;
+		escape_seq_state = 0;
+	}
+
+	void next_char(char ch)
+	{
+		if (escape_seq_state == 0 && ch == '\033') {
+			escape_seq_state = 1;
+			return;
+		}
+		if (escape_seq_state == 1) {
+			escape_seq_state = ch == '[' ? 2 : 0;
+			return;
+		}
+		if (escape_seq_state == 2) {
+			if ((ch < '0' || '9' < ch) && ch != ';')
+				escape_seq_state = 0;
+			return;
+		}
+		escape_seq_state = 0;
+		if (ch == '\r') {
+			got_cr = true;
+			return;
+		}
+		if (ch == '\n') {
+			log("ABC: %s\n", replace_tempdir(linebuf, tempdir_name, show_tempdir).c_str());
+			got_cr = false, linebuf.clear();
+			return;
+		}
+		if (got_cr)
+			got_cr = false, linebuf.clear();
+		linebuf += ch;
+	}
+
+	void next_line(const std::string &line)
+	{
+		//int pi, po;
+		//if (sscanf(line.c_str(), "Start-point = pi%d.  End-point = po%d.", &pi, &po) == 2) {
+		//	log("ABC: Start-point = pi%d (%s).  End-point = po%d (%s).\n",
+		//			pi, pi_map.count(pi) ? pi_map.at(pi).c_str() : "???",
+		//			po, po_map.count(po) ? po_map.at(po).c_str() : "???");
+		//	return;
+		//}
+
+		for (char ch : line)
+			next_char(ch);
+	}
+};
+
+void abc9_module(RTLIL::Design *design, std::string script_file, std::string exe_file,
+		vector<int> lut_costs, bool dff_mode, std::string delay_target, std::string /*lutin_shared*/, bool fast_mode,
+		bool show_tempdir, std::string box_file, std::string lut_file,
+		std::string wire_delay, std::string tempdir_name
+)
+{
+	std::string abc9_script;
+
+	if (!lut_costs.empty())
+		abc9_script += stringf("read_lut %s/lutdefs.txt; ", tempdir_name.c_str());
+	else if (!lut_file.empty())
+		abc9_script += stringf("read_lut %s; ", lut_file.c_str());
+	else
+		log_abort();
+
+	log_assert(!box_file.empty());
+	abc9_script += stringf("read_box %s; ", box_file.c_str());
+	abc9_script += stringf("&read %s/input.xaig; &ps; ", tempdir_name.c_str());
+
+	if (!script_file.empty()) {
+		if (script_file[0] == '+') {
+			for (size_t i = 1; i < script_file.size(); i++)
+				if (script_file[i] == '\'')
+					abc9_script += "'\\''";
+				else if (script_file[i] == ',')
+					abc9_script += " ";
+				else
+					abc9_script += script_file[i];
+		} else
+			abc9_script += stringf("source %s", script_file.c_str());
+	} else if (!lut_costs.empty() || !lut_file.empty()) {
+		abc9_script += fast_mode ? RTLIL::constpad.at("abc9.script.default.fast").substr(1,std::string::npos)
+			: RTLIL::constpad.at("abc9.script.default").substr(1,std::string::npos);
+	} else
+		log_abort();
+
+	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);
+
+	//for (size_t pos = abc9_script.find("{S}"); pos != std::string::npos; pos = abc9_script.find("{S}", pos))
+	//	abc9_script = abc9_script.substr(0, pos) + lutin_shared + abc9_script.substr(pos+3);
+
+	for (size_t pos = abc9_script.find("{W}"); pos != std::string::npos; pos = abc9_script.find("{W}", pos))
+		abc9_script = abc9_script.substr(0, pos) + wire_delay + abc9_script.substr(pos+3);
+
+	std::string C;
+	if (design->scratchpad.count("abc9.if.C"))
+		C = "-C " + design->scratchpad_get_string("abc9.if.C");
+	for (size_t pos = abc9_script.find("{C}"); pos != std::string::npos; pos = abc9_script.find("{C}", pos))
+		abc9_script = abc9_script.substr(0, pos) + C + abc9_script.substr(pos+3);
+
+	std::string R;
+	if (design->scratchpad.count("abc9.if.R"))
+		R = "-R " + design->scratchpad_get_string("abc9.if.R");
+	for (size_t pos = abc9_script.find("{R}"); pos != std::string::npos; pos = abc9_script.find("{R}", pos))
+		abc9_script = abc9_script.substr(0, pos) + R + abc9_script.substr(pos+3);
+
+	abc9_script += stringf("; &ps -l; &write -n %s/output.aig", tempdir_name.c_str());
+	if (design->scratchpad_get_bool("abc9.verify")) {
+		if (dff_mode)
+			abc9_script += "; verify -s";
+		else
+			abc9_script += "; verify";
+	}
+	abc9_script += "; time";
+	abc9_script = add_echos_to_abc9_cmd(abc9_script);
+
+	for (size_t i = 0; i+1 < abc9_script.size(); i++)
+		if (abc9_script[i] == ';' && abc9_script[i+1] == ' ')
+			abc9_script[i+1] = '\n';
+
+	FILE *f = fopen(stringf("%s/abc.script", tempdir_name.c_str()).c_str(), "wt");
+	fprintf(f, "%s\n", abc9_script.c_str());
+	fclose(f);
+
+	std::string buffer;
+
+	log_header(design, "Executing ABC9.\n");
+
+	if (!lut_costs.empty()) {
+		buffer = stringf("%s/lutdefs.txt", tempdir_name.c_str());
+		f = fopen(buffer.c_str(), "wt");
+		if (f == NULL)
+			log_error("Opening %s for writing failed: %s\n", buffer.c_str(), strerror(errno));
+		for (int i = 0; i < GetSize(lut_costs); i++)
+			fprintf(f, "%d %d.00 1.00\n", i+1, lut_costs.at(i));
+		fclose(f);
+	}
+
+	buffer = stringf("%s -s -f %s/abc.script 2>&1", exe_file.c_str(), tempdir_name.c_str());
+	log("Running ABC command: %s\n", replace_tempdir(buffer, tempdir_name, show_tempdir).c_str());
+
+#ifndef YOSYS_LINK_ABC
+	abc9_output_filter filt(tempdir_name, show_tempdir);
+	int ret = run_command(buffer, std::bind(&abc9_output_filter::next_line, filt, std::placeholders::_1));
+#else
+	// These needs to be mutable, supposedly due to getopt
+	char *abc9_argv[5];
+	string tmp_script_name = stringf("%s/abc.script", tempdir_name.c_str());
+	abc9_argv[0] = strdup(exe_file.c_str());
+	abc9_argv[1] = strdup("-s");
+	abc9_argv[2] = strdup("-f");
+	abc9_argv[3] = strdup(tmp_script_name.c_str());
+	abc9_argv[4] = 0;
+	int ret = Abc_RealMain(4, abc9_argv);
+	free(abc9_argv[0]);
+	free(abc9_argv[1]);
+	free(abc9_argv[2]);
+	free(abc9_argv[3]);
+#endif
+	if (ret != 0)
+		log_error("ABC: execution of command \"%s\" failed: return code %d.\n", buffer.c_str(), ret);
+}
+
+struct Abc9ExePass : public Pass {
+	Abc9ExePass() : Pass("abc9_exe", "use ABC9 for technology mapping") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    abc9_exe [options]\n");
+		log("\n");
+		log(" \n");
+		log("This pass uses the ABC tool [1] for technology mapping of the top module\n");
+		log("(according to the (* top *) attribute or if only one module is currently selected)\n");
+		log("to a target FPGA architecture.\n");
+		log("\n");
+		log("    -exe <command>\n");
+#ifdef ABCEXTERNAL
+		log("        use the specified command instead of \"" ABCEXTERNAL "\" to execute ABC.\n");
+#else
+		log("        use the specified command instead of \"<yosys-bindir>/yosys-abc\" to execute ABC.\n");
+#endif
+		log("        This can e.g. be used to call a specific version of ABC or a wrapper.\n");
+		log("\n");
+		log("    -script <file>\n");
+		log("        use the specified ABC script file instead of the default script.\n");
+		log("\n");
+		log("        if <file> starts with a plus sign (+), then the rest of the filename\n");
+		log("        string is interpreted as the command string to be passed to ABC. The\n");
+		log("        leading plus sign is removed and all commas (,) in the string are\n");
+		log("        replaced with blanks before the string is passed to ABC.\n");
+		log("\n");
+		log("        if no -script parameter is given, the following scripts are used:\n");
+		log("%s\n", fold_abc9_cmd(RTLIL::constpad.at("abc9.script.default").substr(1,std::string::npos)).c_str());
+		log("\n");
+		log("    -fast\n");
+		log("        use different default scripts that are slightly faster (at the cost\n");
+		log("        of output quality):\n");
+		log("%s\n", fold_abc9_cmd(RTLIL::constpad.at("abc9.script.default.fast").substr(1,std::string::npos)).c_str());
+		log("\n");
+		log("    -D <picoseconds>\n");
+		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("\n");
+//		log("    -S <num>\n");
+//		log("        maximum number of LUT inputs shared.\n");
+//		log("        (replaces {S} in the default scripts above, default: -S 1)\n");
+//		log("\n");
+		log("    -lut <width>\n");
+		log("        generate netlist using luts of (max) the specified width.\n");
+		log("\n");
+		log("    -lut <w1>:<w2>\n");
+		log("        generate netlist using luts of (max) the specified width <w2>. All\n");
+		log("        luts with width <= <w1> have constant cost. for luts larger than <w1>\n");
+		log("        the area cost doubles with each additional input bit. the delay cost\n");
+		log("        is still constant for all lut widths.\n");
+		log("\n");
+		log("    -lut <file>\n");
+		log("        pass this file with lut library to ABC.\n");
+		log("\n");
+		log("    -luts <cost1>,<cost2>,<cost3>,<sizeN>:<cost4-N>,..\n");
+		log("        generate netlist using luts. Use the specified costs for luts with 1,\n");
+		log("        2, 3, .. inputs.\n");
+		log("\n");
+		log("    -showtmp\n");
+		log("        print the temp dir name in log. usually this is suppressed so that the\n");
+		log("        command output is identical across runs.\n");
+		log("\n");
+		log("    -box <file>\n");
+		log("        pass this file with box library to ABC.\n");
+		log("\n");
+		log("    -cwd <dir>\n");
+		log("        use this as the current working directory, inside which the 'input.xaig'\n");
+		log("        file is expected. temporary files will be created in this directory, and\n");
+		log("        the mapped result will be written to 'output.aig'.\n");
+		log("\n");
+		log("Note that this is a logic optimization pass within Yosys that is calling ABC\n");
+		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("\n");
+		log("[1] http://www.eecs.berkeley.edu/~alanmi/abc/\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing ABC9_MAP pass (technology mapping using ABC9).\n");
+
+#ifdef ABCEXTERNAL
+		std::string exe_file = ABCEXTERNAL;
+#else
+		std::string exe_file = proc_self_dirname() + "yosys-abc";
+#endif
+		std::string script_file, clk_str, box_file, lut_file;
+		std::string delay_target, lutin_shared = "-S 1", wire_delay;
+		std::string tempdir_name;
+		bool fast_mode = false, dff_mode = false;
+		bool show_tempdir = false;
+		vector<int> lut_costs;
+
+#if 0
+		cleanup = false;
+		show_tempdir = true;
+#endif
+
+#ifdef _WIN32
+#ifndef ABCEXTERNAL
+		if (!check_file_exists(exe_file + ".exe") && check_file_exists(proc_self_dirname() + "..\\yosys-abc.exe"))
+			exe_file = proc_self_dirname() + "..\\yosys-abc";
+#endif
+#endif
+
+		std::string lut_arg, luts_arg;
+		exe_file = design->scratchpad_get_string("abc9.exe", exe_file /* inherit default value if not set */);
+		script_file = design->scratchpad_get_string("abc9.script", script_file);
+		if (design->scratchpad.count("abc9.D")) {
+			delay_target = "-D " + design->scratchpad_get_string("abc9.D");
+		}
+		lut_arg = design->scratchpad_get_string("abc9.lut", lut_arg);
+		luts_arg = design->scratchpad_get_string("abc9.luts", luts_arg);
+		fast_mode = design->scratchpad_get_bool("abc9.fast", fast_mode);
+		dff_mode = design->scratchpad_get_bool("abc9.dff", dff_mode);
+		show_tempdir = design->scratchpad_get_bool("abc9.showtmp", show_tempdir);
+		box_file = design->scratchpad_get_string("abc9.box", box_file);
+		if (design->scratchpad.count("abc9.W")) {
+			wire_delay = "-W " + design->scratchpad_get_string("abc9.W");
+		}
+
+		size_t argidx;
+		char pwd [PATH_MAX];
+		if (!getcwd(pwd, sizeof(pwd))) {
+			log_cmd_error("getcwd failed: %s\n", strerror(errno));
+			log_abort();
+		}
+		for (argidx = 1; argidx < args.size(); argidx++) {
+			std::string arg = args[argidx];
+			if (arg == "-exe" && argidx+1 < args.size()) {
+				exe_file = args[++argidx];
+				continue;
+			}
+			if (arg == "-script" && argidx+1 < args.size()) {
+				script_file = args[++argidx];
+				continue;
+			}
+			if (arg == "-D" && argidx+1 < args.size()) {
+				delay_target = "-D " + args[++argidx];
+				continue;
+			}
+			//if (arg == "-S" && argidx+1 < args.size()) {
+			//	lutin_shared = "-S " + args[++argidx];
+			//	continue;
+			//}
+			if (arg == "-lut" && argidx+1 < args.size()) {
+				lut_arg = args[++argidx];
+				continue;
+			}
+			if (arg == "-luts" && argidx+1 < args.size()) {
+				lut_arg = args[++argidx];
+				continue;
+			}
+			if (arg == "-fast") {
+				fast_mode = true;
+				continue;
+			}
+			if (arg == "-dff") {
+				dff_mode = true;
+				continue;
+			}
+			if (arg == "-showtmp") {
+				show_tempdir = true;
+				continue;
+			}
+			if (arg == "-box" && argidx+1 < args.size()) {
+				box_file = args[++argidx];
+				continue;
+			}
+			if (arg == "-W" && argidx+1 < args.size()) {
+				wire_delay = "-W " + args[++argidx];
+				continue;
+			}
+			if (arg == "-cwd" && argidx+1 < args.size()) {
+				tempdir_name = args[++argidx];
+				continue;
+			}
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		rewrite_filename(script_file);
+		if (!script_file.empty() && !is_absolute_path(script_file) && script_file[0] != '+')
+			script_file = std::string(pwd) + "/" + script_file;
+
+		// handle -lut / -luts args
+		if (!lut_arg.empty()) {
+			string arg = lut_arg;
+			if (arg.find_first_not_of("0123456789:") == std::string::npos) {
+				size_t pos = arg.find_first_of(':');
+				int lut_mode = 0, lut_mode2 = 0;
+				if (pos != string::npos) {
+					lut_mode = atoi(arg.substr(0, pos).c_str());
+					lut_mode2 = atoi(arg.substr(pos+1).c_str());
+				} else {
+					lut_mode = atoi(arg.c_str());
+					lut_mode2 = lut_mode;
+				}
+				lut_costs.clear();
+				for (int i = 0; i < lut_mode; i++)
+					lut_costs.push_back(1);
+				for (int i = lut_mode; i < lut_mode2; i++)
+					lut_costs.push_back(2 << (i - lut_mode));
+			}
+			else {
+				lut_file = arg;
+				rewrite_filename(lut_file);
+				if (!lut_file.empty() && !is_absolute_path(lut_file) && lut_file[0] != '+')
+					lut_file = std::string(pwd) + "/" + lut_file;
+			}
+		}
+		if (!luts_arg.empty()) {
+			lut_costs.clear();
+			for (auto &tok : split_tokens(luts_arg, ",")) {
+				auto parts = split_tokens(tok, ":");
+				if (GetSize(parts) == 0 && !lut_costs.empty())
+					lut_costs.push_back(lut_costs.back());
+				else if (GetSize(parts) == 1)
+					lut_costs.push_back(atoi(parts.at(0).c_str()));
+				else if (GetSize(parts) == 2)
+					while (GetSize(lut_costs) < atoi(parts.at(0).c_str()))
+						lut_costs.push_back(atoi(parts.at(1).c_str()));
+				else
+					log_cmd_error("Invalid -luts syntax.\n");
+			}
+		}
+
+		// ABC expects a box file for XAIG
+		if (box_file.empty())
+			box_file = "+/dummy.box";
+
+		rewrite_filename(box_file);
+		if (!box_file.empty() && !is_absolute_path(box_file) && box_file[0] != '+')
+			box_file = std::string(pwd) + "/" + box_file;
+
+		if (tempdir_name.empty())
+			log_cmd_error("abc9_exe '-cwd' option is mandatory.\n");
+
+
+		abc9_module(design, script_file, exe_file, lut_costs, dff_mode,
+				delay_target, lutin_shared, fast_mode, show_tempdir,
+				box_file, lut_file, wire_delay, tempdir_name);
+	}
+} Abc9ExePass;
+
+PRIVATE_NAMESPACE_END
diff --git a/passes/techmap/abc9_ops.cc b/passes/techmap/abc9_ops.cc
new file mode 100644
index 000000000..9ad29a8f6
--- /dev/null
+++ b/passes/techmap/abc9_ops.cc
@@ -0,0 +1,825 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *                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
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "kernel/register.h"
+#include "kernel/sigtools.h"
+#include "kernel/utils.h"
+#include "kernel/celltypes.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+int map_autoidx;
+
+inline std::string remap_name(RTLIL::IdString abc9_name)
+{
+	return stringf("$abc$%d$%s", map_autoidx, abc9_name.c_str()+1);
+}
+
+void mark_scc(RTLIL::Module *module)
+{
+	// For every unique SCC found, (arbitrarily) find the first
+	//   cell in the component, and convert all wires driven by
+	//   its output ports into a new PO, and drive its previous
+	//   sinks with a new PI
+	pool<RTLIL::Const> ids_seen;
+	for (auto cell : module->cells()) {
+		auto it = cell->attributes.find(ID(abc9_scc_id));
+		if (it == cell->attributes.end())
+			continue;
+		auto id = it->second;
+		auto r = ids_seen.insert(id);
+		cell->attributes.erase(it);
+		if (!r.second)
+			continue;
+		for (auto &c : cell->connections_) {
+			if (c.second.is_fully_const()) continue;
+			if (cell->output(c.first)) {
+				SigBit b = c.second.as_bit();
+				Wire *w = b.wire;
+				w->set_bool_attribute(ID::keep);
+				w->attributes[ID(abc9_scc_id)] = id.as_int();
+			}
+		}
+	}
+
+	module->fixup_ports();
+}
+
+void prep_dff(RTLIL::Module *module)
+{
+	auto design = module->design;
+	log_assert(design);
+
+	SigMap assign_map(module);
+
+	typedef SigSpec clkdomain_t;
+	dict<clkdomain_t, int> clk_to_mergeability;
+
+	for (auto cell : module->cells()) {
+		if (cell->type != "$__ABC9_FF_")
+			continue;
+
+		Wire *abc9_clock_wire = module->wire(stringf("%s.clock", cell->name.c_str()));
+		if (abc9_clock_wire == NULL)
+			log_error("'%s.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);
+
+		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.init", cell->name.c_str()));
+		if (abc9_init_wire == NULL)
+			log_error("'%s.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.init' is not a constant wire present in module '%s'.\n", cell->name.c_str(), log_id(module));
+		if (abc9_init == State::S1)
+			log_error("'%s.init' in module '%s' has value 1'b1 which is not supported by 'abc9 -dff'.\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);
+	}
+
+	RTLIL::Module *holes_module = design->module(stringf("%s$holes", module->name.c_str()));
+	if (holes_module) {
+		SigMap sigmap(holes_module);
+
+		dict<SigSpec, SigSpec> replace;
+		for (auto cell : holes_module->cells().to_vector()) {
+			if (!cell->type.in("$_DFF_N_", "$_DFF_NN0_", "$_DFF_NN1_", "$_DFF_NP0_", "$_DFF_NP1_",
+						"$_DFF_P_", "$_DFF_PN0_", "$_DFF_PN1", "$_DFF_PP0_", "$_DFF_PP1_"))
+				continue;
+			SigBit D = cell->getPort("\\D");
+			SigBit Q = cell->getPort("\\Q");
+			// Emulate async control embedded inside $_DFF_* cell with mux in front of D
+			if (cell->type.in("$_DFF_NN0_", "$_DFF_PN0_"))
+				D = holes_module->MuxGate(NEW_ID, State::S0, D, cell->getPort("\\R"));
+			else if (cell->type.in("$_DFF_NN1_", "$_DFF_PN1_"))
+				D = holes_module->MuxGate(NEW_ID, State::S1, D, cell->getPort("\\R"));
+			else if (cell->type.in("$_DFF_NP0_", "$_DFF_PP0_"))
+				D = holes_module->MuxGate(NEW_ID, D, State::S0, cell->getPort("\\R"));
+			else if (cell->type.in("$_DFF_NP1_", "$_DFF_PP1_"))
+				D = holes_module->MuxGate(NEW_ID, D, State::S1, cell->getPort("\\R"));
+			// Remove the $_DFF_* cell from what needs to be a combinatorial box
+			holes_module->remove(cell);
+			Wire *port;
+			if (GetSize(Q.wire) == 1)
+				port = holes_module->wire(stringf("$abc%s", Q.wire->name.c_str()));
+			else
+				port = holes_module->wire(stringf("$abc%s[%d]", Q.wire->name.c_str(), Q.offset));
+			log_assert(port);
+			// Prepare to replace "assign <port> = $_DFF_*.Q;" with "assign <port> = $_DFF_*.D;"
+			//   in order to extract just the combinatorial control logic that feeds the box
+			//   (i.e. clock enable, synchronous reset, etc.)
+			replace.insert(std::make_pair(Q,D));
+			// Since `flatten` above would have created wires named "<cell>.Q",
+			//   extract the pre-techmap cell name
+			auto pos = Q.wire->name.str().rfind(".");
+			log_assert(pos != std::string::npos);
+			IdString driver = Q.wire->name.substr(0, pos);
+			// And drive the signal that was previously driven by "DFF.Q" (typically
+			//   used to implement clock-enable functionality) with the "<cell>.$abc9_currQ"
+			//   wire (which itself is driven an by input port) we inserted above
+			Wire *currQ = holes_module->wire(stringf("%s.abc9_ff.Q", driver.c_str()));
+			log_assert(currQ);
+			holes_module->connect(Q, currQ);
+		}
+
+		for (auto &conn : holes_module->connections_)
+			conn.second = replace.at(sigmap(conn.second), conn.second);
+	}
+}
+
+void prep_xaiger(RTLIL::Module *module, bool dff)
+{
+	auto design = module->design;
+	log_assert(design);
+
+	SigMap sigmap(module);
+
+	dict<SigBit, pool<IdString>> bit_drivers, bit_users;
+	TopoSort<IdString, RTLIL::sort_by_id_str> toposort;
+	dict<IdString, std::vector<IdString>> box_ports;
+
+	for (auto cell : module->cells()) {
+		if (cell->type == "$__ABC9_FF_")
+			continue;
+		if (cell->has_keep_attr())
+			continue;
+
+		auto inst_module = module->design->module(cell->type);
+		bool abc9_box = inst_module && inst_module->attributes.count("\\abc9_box_id");
+		bool abc9_flop = false;
+		if (abc9_box) {
+			abc9_flop = inst_module->get_bool_attribute("\\abc9_flop");
+			if (abc9_flop && !dff)
+				continue;
+
+			auto r = box_ports.insert(cell->type);
+			if (r.second) {
+				// Make carry in the last PI, and carry out the last PO
+				//   since ABC requires it this way
+				IdString carry_in, carry_out;
+				for (const auto &port_name : inst_module->ports) {
+					auto w = inst_module->wire(port_name);
+					log_assert(w);
+					if (w->get_bool_attribute("\\abc9_carry")) {
+						if (w->port_input) {
+							if (carry_in != IdString())
+								log_error("Module '%s' contains more than one 'abc9_carry' input port.\n", log_id(inst_module));
+							carry_in = port_name;
+						}
+						if (w->port_output) {
+							if (carry_out != IdString())
+								log_error("Module '%s' contains more than one 'abc9_carry' output port.\n", log_id(inst_module));
+							carry_out = port_name;
+						}
+					}
+					else
+						r.first->second.push_back(port_name);
+				}
+
+				if (carry_in != IdString() && carry_out == IdString())
+					log_error("Module '%s' contains an 'abc9_carry' input port but no output port.\n", log_id(inst_module));
+				if (carry_in == IdString() && carry_out != IdString())
+					log_error("Module '%s' contains an 'abc9_carry' output port but no input port.\n", log_id(inst_module));
+				if (carry_in != IdString()) {
+					r.first->second.push_back(carry_in);
+					r.first->second.push_back(carry_out);
+				}
+			}
+		}
+		else if (!yosys_celltypes.cell_known(cell->type))
+			continue;
+
+		// TODO: Speed up toposort -- we care about box ordering only
+		for (auto conn : cell->connections()) {
+			if (cell->input(conn.first))
+				for (auto bit : sigmap(conn.second))
+					bit_users[bit].insert(cell->name);
+
+			if (cell->output(conn.first) && !abc9_flop)
+				for (auto bit : sigmap(conn.second))
+					bit_drivers[bit].insert(cell->name);
+		}
+		toposort.node(cell->name);
+	}
+
+	if (box_ports.empty())
+		return;
+
+	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);
+
+	if (ys_debug(1))
+		toposort.analyze_loops = true;
+
+	bool no_loops YS_ATTRIBUTE(unused) = toposort.sort();
+
+	if (ys_debug(1)) {
+		unsigned i = 0;
+		for (auto &it : toposort.loops) {
+			log("  loop %d\n", i++);
+			for (auto cell_name : it) {
+				auto cell = module->cell(cell_name);
+				log_assert(cell);
+				log("\t%s (%s @ %s)\n", log_id(cell), log_id(cell->type), cell->get_src_attribute().c_str());
+			}
+		}
+	}
+
+	log_assert(no_loops);
+
+	RTLIL::Module *holes_module = design->addModule(stringf("%s$holes", module->name.c_str()));
+	log_assert(holes_module);
+	holes_module->set_bool_attribute("\\abc9_holes");
+
+	dict<IdString, Cell*> cell_cache;
+
+	int port_id = 1, box_count = 0;
+	for (auto cell_name : toposort.sorted) {
+		RTLIL::Cell *cell = module->cell(cell_name);
+		log_assert(cell);
+
+		RTLIL::Module* box_module = design->module(cell->type);
+		if (!box_module || !box_module->attributes.count("\\abc9_box_id"))
+			continue;
+
+		cell->attributes["\\abc9_box_seq"] = box_count++;
+
+		IdString derived_name = box_module->derive(design, cell->parameters);
+		box_module = design->module(derived_name);
+
+		auto r = cell_cache.insert(derived_name);
+		auto &holes_cell = r.first->second;
+		if (r.second) {
+			if (box_module->has_processes())
+				Pass::call_on_module(design, box_module, "proc");
+
+			if (box_module->get_bool_attribute("\\whitebox")) {
+				holes_cell = holes_module->addCell(cell->name, derived_name);
+
+				int box_inputs = 0;
+				for (auto port_name : box_ports.at(cell->type)) {
+					RTLIL::Wire *w = box_module->wire(port_name);
+					log_assert(w);
+					log_assert(!w->port_input || !w->port_output);
+					auto &conn = holes_cell->connections_[port_name];
+					if (w->port_input) {
+						for (int i = 0; i < GetSize(w); i++) {
+							box_inputs++;
+							RTLIL::Wire *holes_wire = holes_module->wire(stringf("\\i%d", box_inputs));
+							if (!holes_wire) {
+								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);
+							}
+							conn.append(holes_wire);
+						}
+					}
+					else if (w->port_output)
+						conn = holes_module->addWire(stringf("%s.%s", derived_name.c_str(), log_id(port_name)), GetSize(w));
+				}
+
+				// For flops only, create an extra 1-bit input that drives a new wire
+				//   called "<cell>.abc9_ff.Q" that is used below
+				if (box_module->get_bool_attribute("\\abc9_flop")) {
+					box_inputs++;
+					Wire *holes_wire = holes_module->wire(stringf("\\i%d", box_inputs));
+					if (!holes_wire) {
+						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);
+					}
+					Wire *Q = holes_module->addWire(stringf("%s.abc9_ff.Q", cell->name.c_str()));
+					holes_module->connect(Q, holes_wire);
+				}
+			}
+			else // box_module is a blackbox
+				log_assert(holes_cell == nullptr);
+		}
+
+		for (auto port_name : box_ports.at(cell->type)) {
+			RTLIL::Wire *w = box_module->wire(port_name);
+			log_assert(w);
+			if (!w->port_output)
+				continue;
+			Wire *holes_wire = holes_module->addWire(stringf("$abc%s.%s", cell->name.c_str(), log_id(port_name)), GetSize(w));
+			holes_wire->port_output = true;
+			holes_wire->port_id = port_id++;
+			holes_module->ports.push_back(holes_wire->name);
+			if (holes_cell) // whitebox
+				holes_module->connect(holes_wire, holes_cell->getPort(port_name));
+			else // blackbox
+				holes_module->connect(holes_wire, Const(State::S0, GetSize(w)));
+		}
+	}
+}
+
+void reintegrate(RTLIL::Module *module)
+{
+	auto design = module->design;
+	log_assert(design);
+
+	map_autoidx = autoidx++;
+
+	RTLIL::Module *mapped_mod = design->module(stringf("%s$abc9", module->name.c_str()));
+	if (mapped_mod == NULL)
+		log_error("ABC output file does not contain a module `%s$abc'.\n", log_id(module));
+
+	for (auto w : mapped_mod->wires())
+		module->addWire(remap_name(w->name), GetSize(w));
+
+	dict<IdString,std::vector<IdString>> box_ports;
+
+	for (auto m : design->modules()) {
+		if (!m->attributes.count(ID(abc9_box_id)))
+			continue;
+
+		auto r = box_ports.insert(m->name);
+		if (r.second) {
+			// Make carry in the last PI, and carry out the last PO
+			//   since ABC requires it this way
+			IdString carry_in, carry_out;
+			for (const auto &port_name : m->ports) {
+				auto w = m->wire(port_name);
+				log_assert(w);
+				if (w->get_bool_attribute("\\abc9_carry")) {
+					if (w->port_input) {
+						if (carry_in != IdString())
+							log_error("Module '%s' contains more than one 'abc9_carry' input port.\n", log_id(m));
+						carry_in = port_name;
+					}
+					if (w->port_output) {
+						if (carry_out != IdString())
+							log_error("Module '%s' contains more than one 'abc9_carry' output port.\n", log_id(m));
+						carry_out = port_name;
+					}
+				}
+				else
+					r.first->second.push_back(port_name);
+			}
+
+			if (carry_in != IdString() && carry_out == IdString())
+				log_error("Module '%s' contains an 'abc9_carry' input port but no output port.\n", log_id(m));
+			if (carry_in == IdString() && carry_out != IdString())
+				log_error("Module '%s' contains an 'abc9_carry' output port but no input port.\n", log_id(m));
+			if (carry_in != IdString()) {
+				r.first->second.push_back(carry_in);
+				r.first->second.push_back(carry_out);
+			}
+		}
+	}
+
+	std::vector<Cell*> boxes;
+	for (auto cell : module->cells().to_vector()) {
+		if (cell->has_keep_attr())
+			continue;
+		if (cell->type.in(ID($_AND_), ID($_NOT_), ID($__ABC9_FF_)))
+			module->remove(cell);
+		else if (cell->attributes.erase("\\abc9_box_seq"))
+			boxes.emplace_back(cell);
+	}
+
+	dict<SigBit, pool<IdString>> bit_drivers, bit_users;
+	TopoSort<IdString, RTLIL::sort_by_id_str> toposort;
+	dict<RTLIL::Cell*,RTLIL::Cell*> not2drivers;
+	dict<SigBit, std::vector<RTLIL::Cell*>> bit2sinks;
+
+	std::map<IdString, int> cell_stats;
+	for (auto mapped_cell : mapped_mod->cells())
+	{
+		// TODO: Speed up toposort -- we care about NOT ordering only
+		toposort.node(mapped_cell->name);
+
+		if (mapped_cell->type == ID($_NOT_)) {
+			RTLIL::SigBit a_bit = mapped_cell->getPort(ID::A);
+			RTLIL::SigBit y_bit = mapped_cell->getPort(ID::Y);
+			bit_users[a_bit].insert(mapped_cell->name);
+			// Ignore inouts for topo ordering
+			if (y_bit.wire && !(y_bit.wire->port_input && y_bit.wire->port_output))
+				bit_drivers[y_bit].insert(mapped_cell->name);
+
+			if (!a_bit.wire) {
+				mapped_cell->setPort(ID::Y, module->addWire(NEW_ID));
+				RTLIL::Wire *wire = module->wire(remap_name(y_bit.wire->name));
+				log_assert(wire);
+				module->connect(RTLIL::SigBit(wire, y_bit.offset), State::S1);
+			}
+			else {
+				RTLIL::Cell* driver_lut = nullptr;
+				// ABC can return NOT gates that drive POs
+				if (!a_bit.wire->port_input) {
+					// If it's not a NOT gate that that comes from a PI directly,
+					// find the driver LUT and clone that to guarantee that we won't
+					// increase the max logic depth
+					// (TODO: Optimise by not cloning unless will increase depth)
+					RTLIL::IdString driver_name;
+					if (GetSize(a_bit.wire) == 1)
+						driver_name = stringf("$lut%s", a_bit.wire->name.c_str());
+					else
+						driver_name = stringf("$lut%s[%d]", a_bit.wire->name.c_str(), a_bit.offset);
+					driver_lut = mapped_mod->cell(driver_name);
+				}
+
+				if (!driver_lut) {
+					// If a driver couldn't be found (could be from PI or box CI)
+					// then implement using a LUT
+					RTLIL::Cell *cell = module->addLut(remap_name(stringf("$lut%s", 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"));
+					bit2sinks[cell->getPort(ID::A)].push_back(cell);
+					cell_stats[ID($lut)]++;
+				}
+				else
+					not2drivers[mapped_cell] = driver_lut;
+			}
+			continue;
+		}
+
+		if (mapped_cell->type.in(ID($lut), ID($__ABC9_FF_))) {
+			// Convert buffer into direct connection
+			if (mapped_cell->type == ID($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);
+				log_abort();
+				continue;
+			}
+			RTLIL::Cell *cell = module->addCell(remap_name(mapped_cell->name), mapped_cell->type);
+			cell->parameters = mapped_cell->parameters;
+			cell->attributes = mapped_cell->attributes;
+
+			for (auto &mapped_conn : mapped_cell->connections()) {
+				RTLIL::SigSpec newsig;
+				for (auto c : mapped_conn.second.chunks()) {
+					if (c.width == 0)
+						continue;
+					//log_assert(c.width == 1);
+					if (c.wire)
+						c.wire = module->wires_.at(remap_name(c.wire->name));
+					newsig.append(c);
+				}
+				cell->setPort(mapped_conn.first, newsig);
+
+				if (cell->input(mapped_conn.first)) {
+					for (auto i : newsig)
+						bit2sinks[i].push_back(cell);
+					for (auto i : mapped_conn.second)
+						bit_users[i].insert(mapped_cell->name);
+				}
+				if (cell->output(mapped_conn.first))
+					for (auto i : mapped_conn.second)
+						// Ignore inouts for topo ordering
+						if (i.wire && !(i.wire->port_input && i.wire->port_output))
+							bit_drivers[i].insert(mapped_cell->name);
+			}
+		}
+		else {
+			RTLIL::Cell *existing_cell = module->cell(mapped_cell->name);
+			log_assert(existing_cell);
+
+			RTLIL::Module* box_module = design->module(existing_cell->type);
+			auto it = box_module->attributes.find(ID(abc9_box_id));
+			log_assert(it != box_module->attributes.end());
+			log_assert(mapped_cell->type == stringf("$__boxid%d", it->second.as_int()));
+			mapped_cell->type = existing_cell->type;
+
+			RTLIL::Cell *cell = module->addCell(remap_name(mapped_cell->name), mapped_cell->type);
+			cell->parameters = existing_cell->parameters;
+			cell->attributes = existing_cell->attributes;
+			module->swap_names(cell, existing_cell);
+
+			auto jt = mapped_cell->connections_.find("\\i");
+			log_assert(jt != mapped_cell->connections_.end());
+			SigSpec inputs = std::move(jt->second);
+			mapped_cell->connections_.erase(jt);
+			jt = mapped_cell->connections_.find("\\o");
+			log_assert(jt != mapped_cell->connections_.end());
+			SigSpec outputs = std::move(jt->second);
+			mapped_cell->connections_.erase(jt);
+
+			auto abc9_flop = box_module->attributes.count("\\abc9_flop");
+			if (!abc9_flop) {
+				for (const auto &i : inputs)
+					bit_users[i].insert(mapped_cell->name);
+				for (const auto &i : outputs)
+					// Ignore inouts for topo ordering
+					if (i.wire && !(i.wire->port_input && i.wire->port_output))
+						bit_drivers[i].insert(mapped_cell->name);
+			}
+
+			int input_count = 0, output_count = 0;
+			for (const auto &port_name : box_ports.at(cell->type)) {
+				RTLIL::Wire *w = box_module->wire(port_name);
+				log_assert(w);
+
+				SigSpec sig;
+				if (w->port_input) {
+					sig = inputs.extract(input_count, GetSize(w));
+					input_count += GetSize(w);
+				}
+				if (w->port_output) {
+					sig = outputs.extract(output_count, GetSize(w));
+					output_count += GetSize(w);
+				}
+
+				SigSpec newsig;
+				for (auto c : sig.chunks()) {
+					if (c.width == 0)
+						continue;
+					//log_assert(c.width == 1);
+					if (c.wire)
+						c.wire = module->wires_.at(remap_name(c.wire->name));
+					newsig.append(c);
+				}
+				cell->setPort(port_name, newsig);
+
+				if (w->port_input && !abc9_flop)
+					for (const auto &i : newsig)
+						bit2sinks[i].push_back(cell);
+			}
+		}
+
+		cell_stats[mapped_cell->type]++;
+	}
+
+	for (auto cell : boxes)
+		module->remove(cell);
+
+	// Copy connections (and rename) from mapped_mod to module
+	for (auto conn : mapped_mod->connections()) {
+		if (!conn.first.is_fully_const()) {
+			auto chunks = conn.first.chunks();
+			for (auto &c : chunks)
+				c.wire = module->wires_.at(remap_name(c.wire->name));
+			conn.first = std::move(chunks);
+		}
+		if (!conn.second.is_fully_const()) {
+			auto chunks = conn.second.chunks();
+			for (auto &c : chunks)
+				if (c.wire)
+					c.wire = module->wires_.at(remap_name(c.wire->name));
+			conn.second = std::move(chunks);
+		}
+		module->connect(conn);
+	}
+
+	for (auto &it : cell_stats)
+		log("ABC RESULTS:   %15s cells: %8d\n", it.first.c_str(), it.second);
+	int in_wires = 0, out_wires = 0;
+
+	// Stitch in mapped_mod's inputs/outputs into module
+	for (auto port : mapped_mod->ports) {
+		RTLIL::Wire *mapped_wire = mapped_mod->wire(port);
+		RTLIL::Wire *wire = module->wire(port);
+		log_assert(wire);
+		if (wire->attributes.erase(ID(abc9_scc_id))) {
+			auto r YS_ATTRIBUTE(unused) = wire->attributes.erase(ID::keep);
+			log_assert(r);
+		}
+		RTLIL::Wire *remap_wire = module->wire(remap_name(port));
+		RTLIL::SigSpec signal(wire, 0, GetSize(remap_wire));
+		log_assert(GetSize(signal) >= GetSize(remap_wire));
+
+		RTLIL::SigSig conn;
+		if (mapped_wire->port_output) {
+			conn.first = signal;
+			conn.second = remap_wire;
+			out_wires++;
+			module->connect(conn);
+		}
+		else if (mapped_wire->port_input) {
+			conn.first = remap_wire;
+			conn.second = signal;
+			in_wires++;
+			module->connect(conn);
+		}
+	}
+
+	// ABC9 will return $_NOT_ gates in its mapping (since they are
+	//   treated as being "free"), in particular driving primary
+	//   outputs (real primary outputs, or cells treated as blackboxes)
+	//   or driving box inputs.
+	// Instead of just mapping those $_NOT_ gates into 2-input $lut-s
+	//   at an area and delay cost, see if it is possible to push
+	//   this $_NOT_ into the driving LUT, or into all sink LUTs.
+	// When this is not possible, (i.e. this signal drives two primary
+	//   outputs, only one of which is complemented) and when the driver
+	//   is a LUT, then clone the LUT so that it can be inverted without
+	//   increasing depth/delay.
+	for (auto &it : bit_users)
+		if (bit_drivers.count(it.first))
+			for (auto driver_cell : bit_drivers.at(it.first))
+			for (auto user_cell : it.second)
+				toposort.edge(driver_cell, user_cell);
+	bool no_loops YS_ATTRIBUTE(unused) = toposort.sort();
+	log_assert(no_loops);
+
+	for (auto ii = toposort.sorted.rbegin(); ii != toposort.sorted.rend(); ii++) {
+		RTLIL::Cell *not_cell = mapped_mod->cell(*ii);
+		log_assert(not_cell);
+		if (not_cell->type != ID($_NOT_))
+			continue;
+		auto it = not2drivers.find(not_cell);
+		if (it == not2drivers.end())
+			continue;
+		RTLIL::Cell *driver_lut = it->second;
+		RTLIL::SigBit a_bit = not_cell->getPort(ID::A);
+		RTLIL::SigBit y_bit = not_cell->getPort(ID::Y);
+		RTLIL::Const driver_mask;
+
+		a_bit.wire = module->wires_.at(remap_name(a_bit.wire->name));
+		y_bit.wire = module->wires_.at(remap_name(y_bit.wire->name));
+
+		auto jt = bit2sinks.find(a_bit);
+		if (jt == bit2sinks.end())
+			goto clone_lut;
+
+		for (auto sink_cell : jt->second)
+			if (sink_cell->type != ID($lut))
+				goto clone_lut;
+
+		// Push downstream LUTs past inverter
+		for (auto sink_cell : jt->second) {
+			SigSpec A = sink_cell->getPort(ID::A);
+			RTLIL::Const mask = sink_cell->getParam(ID(LUT));
+			int index = 0;
+			for (; index < GetSize(A); index++)
+				if (A[index] == a_bit)
+					break;
+			log_assert(index < GetSize(A));
+			int i = 0;
+			while (i < GetSize(mask)) {
+				for (int j = 0; j < (1 << index); j++)
+					std::swap(mask[i+j], mask[i+j+(1 << index)]);
+				i += 1 << (index+1);
+			}
+			A[index] = y_bit;
+			sink_cell->setPort(ID::A, A);
+			sink_cell->setParam(ID(LUT), mask);
+		}
+
+		// Since we have rewritten all sinks (which we know
+		// to be only LUTs) to be after the inverter, we can
+		// go ahead and clone the LUT with the expectation
+		// that the original driving LUT will become dangling
+		// and get cleaned away
+clone_lut:
+		driver_mask = driver_lut->getParam(ID(LUT));
+		for (auto &b : driver_mask.bits) {
+			if (b == RTLIL::State::S0) b = RTLIL::State::S1;
+			else if (b == RTLIL::State::S1) b = RTLIL::State::S0;
+		}
+		auto cell = module->addLut(NEW_ID,
+				driver_lut->getPort(ID::A),
+				y_bit,
+				driver_mask);
+		for (auto &bit : cell->connections_.at(ID::A)) {
+			bit.wire = module->wires_.at(remap_name(bit.wire->name));
+			bit2sinks[bit].push_back(cell);
+		}
+	}
+
+	//log("ABC RESULTS:        internal signals: %8d\n", int(signal_list.size()) - in_wires - out_wires);
+	log("ABC RESULTS:           input signals: %8d\n", in_wires);
+	log("ABC RESULTS:          output signals: %8d\n", out_wires);
+
+	design->remove(mapped_mod);
+}
+
+struct Abc9OpsPass : public Pass {
+	Abc9OpsPass() : Pass("abc9_ops", "helper functions for ABC9") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    abc9_ops [options] [selection]\n");
+		log("\n");
+		log("This pass contains a set of supporting operations for use during ABC technology\n");
+		log("mapping, and is expected to be called in conjunction with other operations from\n");
+		log("the `abc9' script pass. Only fully-selected modules are supported.\n");
+		log("\n");
+		log("    -mark_scc\n");
+		log("        for an arbitrarily chosen cell in each unique SCC of each selected module\n");
+		log("        (tagged with an (* abc9_scc_id = <int> *) attribute), temporarily mark all\n");
+		log("        wires driven by this cell's outputs with a (* keep *) attribute in order\n");
+		log("        to break the SCC. this temporary attribute will be removed on -reintegrate.\n");
+		log("\n");
+		log("    -prep_xaiger\n");
+		log("        prepare the design for XAIGER output. this includes computing the\n");
+		log("        topological ordering of ABC9 boxes, as well as preparing the\n");
+		log("        '<module-name>$holes' module that contains the logic behaviour of ABC9\n");
+		log("        whiteboxes.\n");
+		log("\n");
+		log("    -dff\n");
+		log("        consider flop cells (those instantiating modules marked with (* abc9_flop *)\n");
+		log("        during -prep_xaiger.\n");
+		log("\n");
+		log("    -prep_dff\n");
+		log("        compute the clock domain and initial value of each flop in the design.\n");
+		log("        process the '$holes' module to support clock-enable functionality.\n");
+		log("\n");
+		log("    -reintegrate\n");
+		log("        for each selected module, re-intergrate the module '<module-name>$abc9'\n");
+		log("        by first recovering ABC9 boxes, and then stitching in the remaining primary\n");
+		log("        inputs and outputs.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing ABC9_OPS pass (helper functions for ABC9).\n");
+
+		bool mark_scc_mode = false;
+		bool prep_dff_mode = false;
+		bool prep_xaiger_mode = false;
+		bool reintegrate_mode = false;
+		bool dff_mode = false;
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++) {
+			std::string arg = args[argidx];
+			if (arg == "-mark_scc") {
+				mark_scc_mode = true;
+				continue;
+			}
+			if (arg == "-prep_dff") {
+				prep_dff_mode = true;
+				continue;
+			}
+			if (arg == "-prep_xaiger") {
+				prep_xaiger_mode = true;
+				continue;
+			}
+			if (arg == "-reintegrate") {
+				reintegrate_mode = true;
+				continue;
+			}
+			if (arg == "-dff") {
+				dff_mode = true;
+				continue;
+			}
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		if (!(mark_scc_mode || prep_dff_mode || reintegrate_mode))
+			log_cmd_error("At least one of -mark_scc, -prep_{xaiger,dff}, -reintegrate must be specified.\n");
+
+		if (dff_mode && !prep_xaiger_mode)
+			log_cmd_error("'-dff' option is only relevant for -prep_xaiger.\n");
+
+		for (auto mod : design->selected_modules()) {
+			if (mod->get_bool_attribute("\\abc9_holes"))
+				continue;
+
+			if (mod->processes.size() > 0) {
+				log("Skipping module %s as it contains processes.\n", log_id(mod));
+				continue;
+			}
+
+			if (!design->selected_whole_module(mod))
+				log_error("Can't handle partially selected module %s!\n", log_id(mod));
+
+			if (mark_scc_mode)
+				mark_scc(mod);
+			if (prep_dff_mode)
+				prep_dff(mod);
+			if (prep_xaiger_mode)
+				prep_xaiger(mod, dff_mode);
+			if (reintegrate_mode)
+				reintegrate(mod);
+		}
+	}
+} Abc9OpsPass;
+
+PRIVATE_NAMESPACE_END