/*
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
 *  
 *  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/log.h"
#include "kernel/celltypes.h"
#include "libs/sha1/sha1.h"
#include <stdlib.h>
#include <stdio.h>
#include <set>

#define USE_CELL_HASH_CACHE

USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN

struct OptShareWorker
{
	RTLIL::Design *design;
	RTLIL::Module *module;
	SigMap assign_map;
	SigMap dff_init_map;

	CellTypes ct;
	int total_count;
#ifdef USE_CELL_HASH_CACHE
	std::map<const RTLIL::Cell*, std::string> cell_hash_cache;
#endif

#ifdef USE_CELL_HASH_CACHE
	std::string int_to_hash_string(unsigned int v)
	{
		if (v == 0)
			return "0";
		std::string str = "";
		while (v > 0) {
			str += 'a' + (v & 15);
			v = v >> 4;
		}
		return str;
	}

	std::string hash_cell_parameters_and_connections(const RTLIL::Cell *cell)
	{
		if (cell_hash_cache.count(cell) > 0)
			return cell_hash_cache[cell];

		std::string hash_string = cell->type.str() + "\n";

		for (auto &it : cell->parameters)
			hash_string += "P " + it.first.str() + "=" + it.second.as_string() + "\n";

		const std::map<RTLIL::IdString, RTLIL::SigSpec> *conn = &cell->connections();
		std::map<RTLIL::IdString, RTLIL::SigSpec> alt_conn;

		if (cell->type == "$and" || cell->type == "$or" || cell->type == "$xor" || cell->type == "$xnor" || cell->type == "$add" || cell->type == "$mul" ||
				cell->type == "$logic_and" || cell->type == "$logic_or" || cell->type == "$_AND_" || cell->type == "$_OR_" || cell->type == "$_XOR_") {
			alt_conn = *conn;
			if (assign_map(alt_conn.at("\\A")) < assign_map(alt_conn.at("\\B"))) {
				alt_conn["\\A"] = conn->at("\\B");
				alt_conn["\\B"] = conn->at("\\A");
			}
			conn = &alt_conn;
		} else
		if (cell->type == "$reduce_xor" || cell->type == "$reduce_xnor") {
			alt_conn = *conn;
			assign_map.apply(alt_conn.at("\\A"));
			alt_conn.at("\\A").sort();
			conn = &alt_conn;
		} else
		if (cell->type == "$reduce_and" || cell->type == "$reduce_or" || cell->type == "$reduce_bool") {
			alt_conn = *conn;
			assign_map.apply(alt_conn.at("\\A"));
			alt_conn.at("\\A").sort_and_unify();
			conn = &alt_conn;
		}

		for (auto &it : *conn) {
			if (ct.cell_output(cell->type, it.first))
				continue;
			RTLIL::SigSpec sig = it.second;
			assign_map.apply(sig);
			hash_string += "C " + it.first.str() + "=";
			for (auto &chunk : sig.chunks()) {
				if (chunk.wire)
					hash_string += "{" + chunk.wire->name.str() + " " +
							int_to_hash_string(chunk.offset) + " " +
							int_to_hash_string(chunk.width) + "}";
				else
					hash_string += RTLIL::Const(chunk.data).as_string();
			}
			hash_string += "\n";
		}

		cell_hash_cache[cell] = sha1(hash_string);
		return cell_hash_cache[cell];
	}
#endif

	bool compare_cell_parameters_and_connections(const RTLIL::Cell *cell1, const RTLIL::Cell *cell2, bool &lt)
	{
#ifdef USE_CELL_HASH_CACHE
		std::string hash1 = hash_cell_parameters_and_connections(cell1);
		std::string hash2 = hash_cell_parameters_and_connections(cell2);

		if (hash1 != hash2) {
			lt = hash1 < hash2;
			return true;
		}
#endif

		if (cell1->parameters != cell2->parameters) {
			lt = cell1->parameters < cell2->parameters;
			return true;
		}

		std::map<RTLIL::IdString, RTLIL::SigSpec> conn1 = cell1->connections();
		std::map<RTLIL::IdString, RTLIL::SigSpec> conn2 = cell2->connections();

		for (auto &it : conn1) {
			if (ct.cell_output(cell1->type, it.first))
				it.second = RTLIL::SigSpec();
			else
				assign_map.apply(it.second);
		}

		for (auto &it : conn2) {
			if (ct.cell_output(cell2->type, it.first))
				it.second = RTLIL::SigSpec();
			else
				assign_map.apply(it.second);
		}

		if (cell1->type == "$and" || cell1->type == "$or" || cell1->type == "$xor" || cell1->type == "$xnor" || cell1->type == "$add" || cell1->type == "$mul" ||
				cell1->type == "$logic_and" || cell1->type == "$logic_or" || cell1->type == "$_AND_" || cell1->type == "$_OR_" || cell1->type == "$_XOR_") {
			if (conn1.at("\\A") < conn1.at("\\B")) {
				RTLIL::SigSpec tmp = conn1["\\A"];
				conn1["\\A"] = conn1["\\B"];
				conn1["\\B"] = tmp;
			}
			if (conn2.at("\\A") < conn2.at("\\B")) {
				RTLIL::SigSpec tmp = conn2["\\A"];
				conn2["\\A"] = conn2["\\B"];
				conn2["\\B"] = tmp;
			}
		} else
		if (cell1->type == "$reduce_xor" || cell1->type == "$reduce_xnor") {
			conn1["\\A"].sort();
			conn2["\\A"].sort();
		} else
		if (cell1->type == "$reduce_and" || cell1->type == "$reduce_or" || cell1->type == "$reduce_bool") {
			conn1["\\A"].sort_and_unify();
			conn2["\\A"].sort_and_unify();
		}

		if (conn1 != conn2) {
			lt = conn1 < conn2;
			return true;
		}

		if (cell1->type.substr(0, 1) == "$" && conn1.count("\\Q") != 0) {
			std::vector<RTLIL::SigBit> q1 = dff_init_map(cell1->getPort("\\Q")).to_sigbit_vector();
			std::vector<RTLIL::SigBit> q2 = dff_init_map(cell2->getPort("\\Q")).to_sigbit_vector();
			for (size_t i = 0; i < q1.size(); i++)
				if ((q1.at(i).wire == NULL || q2.at(i).wire == NULL) && q1.at(i) != q2.at(i)) {
					lt = q1.at(i) < q2.at(i);
					return true;
				}
		}

		return false;
	}

	bool compare_cells(const RTLIL::Cell *cell1, const RTLIL::Cell *cell2)
	{
		if (cell1->type != cell2->type)
			return cell1->type < cell2->type;

		if (!ct.cell_known(cell1->type))
			return cell1 < cell2;

		if (cell1->get_bool_attribute("\\keep") || cell2->get_bool_attribute("\\keep"))
			return cell1 < cell2;

		bool lt;
		if (compare_cell_parameters_and_connections(cell1, cell2, lt))
			return lt;

		return false;
	}

	struct CompareCells {
		OptShareWorker *that;
		CompareCells(OptShareWorker *that) : that(that) {}
		bool operator()(const RTLIL::Cell *cell1, const RTLIL::Cell *cell2) const {
			return that->compare_cells(cell1, cell2);
		}
	};

	OptShareWorker(RTLIL::Design *design, RTLIL::Module *module, bool mode_nomux) :
		design(design), module(module), assign_map(module)
	{
		total_count = 0;
		ct.setup_internals();
		ct.setup_internals_mem();
		ct.setup_stdcells();
		ct.setup_stdcells_mem();

		if (mode_nomux) {
			ct.cell_types.erase("$mux");
			ct.cell_types.erase("$pmux");
		}

		log("Finding identical cells in module `%s'.\n", module->name.c_str());
		assign_map.set(module);

		dff_init_map.set(module);
		for (auto &it : module->wires_)
			if (it.second->attributes.count("\\init") != 0)
				dff_init_map.add(it.second, it.second->attributes.at("\\init"));

		bool did_something = true;
		while (did_something)
		{
#ifdef USE_CELL_HASH_CACHE
			cell_hash_cache.clear();
#endif
			std::vector<RTLIL::Cell*> cells;
			cells.reserve(module->cells_.size());
			for (auto &it : module->cells_) {
				if (ct.cell_known(it.second->type) && design->selected(module, it.second))
					cells.push_back(it.second);
			}

			did_something = false;
			std::map<RTLIL::Cell*, RTLIL::Cell*, CompareCells> sharemap(CompareCells(this));
			for (auto cell : cells)
			{
				if (sharemap.count(cell) > 0) {
					did_something = true;
					log("  Cell `%s' is identical to cell `%s'.\n", cell->name.c_str(), sharemap[cell]->name.c_str());
					for (auto &it : cell->connections()) {
						if (ct.cell_output(cell->type, it.first)) {
							RTLIL::SigSpec other_sig = sharemap[cell]->getPort(it.first);
							log("    Redirecting output %s: %s = %s\n", it.first.c_str(),
									log_signal(it.second), log_signal(other_sig));
							module->connect(RTLIL::SigSig(it.second, other_sig));
							assign_map.add(it.second, other_sig);
						}
					}
					log("    Removing %s cell `%s' from module `%s'.\n", cell->type.c_str(), cell->name.c_str(), module->name.c_str());
					module->remove(cell);
					total_count++;
				} else {
					sharemap[cell] = cell;
				}
			}
		}
	}
};

struct OptSharePass : public Pass {
	OptSharePass() : Pass("opt_share", "consolidate identical cells") { }
	virtual void help()
	{
		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
		log("\n");
		log("    opt_share [-nomux] [selection]\n");
		log("\n");
		log("This pass identifies cells with identical type and input signals. Such cells\n");
		log("are then merged to one cell.\n");
		log("\n");
		log("    -nomux\n");
		log("        Do not merge MUX cells.\n");
		log("\n");
	}
	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
	{
		log_header("Executing OPT_SHARE pass (detect identical cells).\n");

		bool mode_nomux = false;

		size_t argidx;
		for (argidx = 1; argidx < args.size(); argidx++) {
			std::string arg = args[argidx];
			if (arg == "-nomux") {
				mode_nomux = true;
				continue;
			}
			break;
		}
		extra_args(args, argidx, design);

		int total_count = 0;
		for (auto &mod_it : design->modules_) {
			if (!design->selected(mod_it.second))
				continue;
			OptShareWorker worker(design, mod_it.second, mode_nomux);
			total_count += worker.total_count;
		}

		if (total_count)
			design->scratchpad_set_bool("opt.did_something", true);
		log("Removed a total of %d cells.\n", total_count);
	}
} OptSharePass;
 
PRIVATE_NAMESPACE_END