/*
 *  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

void break_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->selected_cells()) {
		auto it = cell->attributes.find(ID(abc9_scc_id));
		if (it == cell->attributes.end())
			continue;
		auto r = ids_seen.insert(it->second);
		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;
				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);
				}
			}
		}
	}

	module->fixup_ports();
}

void unbreak_scc(RTLIL::Module *module)
{
	// 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();
}

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->selected_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));
		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$holes", module->name.c_str()));
	if (holes_module) {
		dict<SigSig, SigSig> replace;
		for (auto it = holes_module->cells_.begin(); it != holes_module->cells_.end(); ) {
			auto cell = it->second;
			if (cell->type.in("$_DFF_N_", "$_DFF_NN0_", "$_DFF_NN1_", "$_DFF_NP0_", "$_DFF_NP1_",
						"$_DFF_P_", "$_DFF_PN0_", "$_DFF_PN1", "$_DFF_PP0_", "$_DFF_PP1_")) {
				SigBit D = cell->getPort("\\D");
				SigBit Q = cell->getPort("\\Q");
				// Remove the DFF cell from what needs to be a combinatorial box
				it = holes_module->cells_.erase(it);
				Wire *port;
				if (GetSize(Q.wire) == 1)
					port = holes_module->wire(stringf("$abc%s", Q.wire->name.c_str()));
				else
					port = holes_module->wire(stringf("$abc%s[%d]", Q.wire->name.c_str(), Q.offset));
				log_assert(port);
				// Prepare to replace "assign <port> = DFF.Q;" with "assign <port> = DFF.D;"
				//   in order to extract the combinatorial control logic that feeds the box
				//   (i.e. clock enable, synchronous reset, etc.)
				replace.insert(std::make_pair(SigSig(port,Q), SigSig(port,D)));
				// Since `flatten` above would have created wires named "<cell>.Q",
				//   extract the pre-techmap cell name
				auto pos = Q.wire->name.str().rfind(".");
				log_assert(pos != std::string::npos);
				IdString driver = Q.wire->name.substr(0, pos);
				// And drive the signal that was previously driven by "DFF.Q" (typically
				//   used to implement clock-enable functionality) with the "<cell>.$abc9_currQ"
				//   wire (which itself is driven an 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);
			}
			else
				++it;
		}

		for (auto &conn : holes_module->connections_) {
			auto it = replace.find(conn);
			if (it != replace.end())
				conn = it->second;
		}
	}
}

void prep_holes(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;
	bool abc9_box_seen = false;

	for (auto cell : module->selected_cells()) {
		if (cell->type == "$__ABC9_FF_")
			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;
			abc9_box_seen = abc9_box;
		}
		else if (!yosys_celltypes.cell_known(cell->type))
			continue;

		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 (!abc9_box_seen)
		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 0
	toposort.analyze_loops = true;
#endif
	bool no_loops YS_ATTRIBUTE(unused) = toposort.sort();
#if 0
	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());
		}
	}
#endif
	log_assert(no_loops);

	vector<Cell*> box_list;
	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_list.size();
		box_list.emplace_back(cell);
	}
	log_assert(!box_list.empty());

	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;
	dict<IdString, std::vector<IdString>> box_ports;

	int port_id = 1;
	for (auto cell : box_list) {
		RTLIL::Module* orig_box_module = design->module(cell->type);
		log_assert(orig_box_module);
		IdString derived_name = orig_box_module->derive(design, cell->parameters);
		RTLIL::Module* box_module = design->module(derived_name);
		if (box_module->has_processes())
			Pass::call_on_module(design, box_module, "proc");

		int box_inputs = 0;
		auto r = cell_cache.insert(std::make_pair(derived_name, nullptr));
		Cell *holes_cell = r.first->second;
		if (r.second && box_module->get_bool_attribute("\\whitebox")) {
			holes_cell = holes_module->addCell(cell->name, cell->type);
			holes_cell->parameters = cell->parameters;
			r.first->second = holes_cell;
		}

		auto r2 = box_ports.insert(cell->type);
		if (r2.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 : box_module->ports) {
				auto w = box_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(box_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(box_module));
						carry_out = port_name;
					}
				}
				else
					r2.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(box_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(box_module));
			if (carry_in != IdString()) {
				r2.first->second.push_back(carry_in);
				r2.first->second.push_back(carry_out);
			}
		}

		for (const auto &port_name : box_ports.at(cell->type)) {
			RTLIL::Wire *w = box_module->wire(port_name);
			log_assert(w);
			RTLIL::Wire *holes_wire;
			RTLIL::SigSpec port_sig;
			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", box_inputs));
						holes_wire->port_input = true;
						holes_wire->port_id = port_id++;
						holes_module->ports.push_back(holes_wire->name);
					}
					if (holes_cell)
						port_sig.append(holes_wire);
				}
			if (w->port_output)
				for (int i = 0; i < GetSize(w); i++) {
					if (GetSize(w) == 1)
						holes_wire = holes_module->addWire(stringf("$abc%s.%s", cell->name.c_str(), log_id(w->name)));
					else
						holes_wire = holes_module->addWire(stringf("$abc%s.%s[%d]", cell->name.c_str(), log_id(w->name), i));
					holes_wire->port_output = true;
					holes_wire->port_id = port_id++;
					holes_module->ports.push_back(holes_wire->name);
					if (holes_cell)
						port_sig.append(holes_wire);
					else
						holes_module->connect(holes_wire, State::S0);
				}
			if (!port_sig.empty()) {
				if (r.second)
					holes_cell->setPort(w->name, port_sig);
				else
					holes_module->connect(holes_cell->getPort(w->name), port_sig);
			}
		}

		// For flops only, create an extra 1-bit input that drives a new wire
		//   called "<cell>.$abc9_currQ" that is used below
		if (box_module->get_bool_attribute("\\abc9_flop")) {
			log_assert(holes_cell);

			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 *w = holes_module->addWire(stringf("%s.abc9_ff.Q", cell->name.c_str()));
			holes_module->connect(w, holes_wire);
		}
	}
}

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");
	}
	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 break_scc_mode = false;
		bool unbreak_scc_mode = false;
		bool prep_dff_mode = false;
		bool prep_holes_mode = false;
		bool dff_mode = false;

		size_t argidx;
		for (argidx = 1; argidx < args.size(); argidx++) {
			std::string arg = args[argidx];
			if (arg == "-break_scc") {
				break_scc_mode = true;
				continue;
			}
			if (arg == "-unbreak_scc") {
				unbreak_scc_mode = true;
				continue;
			}
			if (arg == "-prep_dff") {
				prep_dff_mode = true;
				continue;
			}
			if (arg == "-prep_holes") {
				prep_holes_mode = true;
				continue;
			}
			if (arg == "-dff") {
				dff_mode = true;
				continue;
			}
			break;
		}
		extra_args(args, argidx, design);

		for (auto mod : design->selected_modules()) {
			if (mod->get_blackbox_attribute())
				continue;
			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 (break_scc_mode)
				break_scc(mod);
			if (unbreak_scc_mode)
				unbreak_scc(mod);
			if (prep_dff_mode)
				prep_dff(mod);
			if (prep_holes_mode)
				prep_holes(mod, dff_mode);
		}
	}
} Abc9OpsPass;

PRIVATE_NAMESPACE_END