yosys/passes/silimate/sat_clockgate.cc

/*
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2024  Silimate Inc.
 *
 *  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/yosys.h"
#include "kernel/sigtools.h"
#include "kernel/ff.h"
#include <fstream>

USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN

void dump_flipflops_to_file(RTLIL::Design *design, const std::string &filename)
{
	std::ofstream outfile(filename);
	if (!outfile.is_open()) {
		log_error("Cannot open file %s for writing\n", filename.c_str());
		return;
	}

	for (auto module : design->selected_modules()) {
		outfile << "Module: " << log_id(module) << "\n";
		log("Module: %s\n", log_id(module));

		for (auto cell : module->cells()) {
			if (cell->is_builtin_ff()) {
				outfile << "  FF: " << log_id(cell) << " (type: " << log_id(cell->type) << ")\n";
				log("  FF: %s (type: %s)\n", log_id(cell), log_id(cell->type));
			}
		}
		outfile << "\n";
	}

	outfile.close();
	log("Wrote flip-flop list to %s\n", filename.c_str());
}

struct SatClockgatePass : public Pass {
	SatClockgatePass() : Pass("sat_clockgate", "SAT-based inferred clock gating") { }

	void help() override
	{
		log("\n");
		log("    sat_clockgate [options] [selection]\n");
		log("\n");
		log("This command performs SAT-based inferred clock gating insertion.\n");
		log("\n");
		log("    -threshold <n>\n");
		log("        minimum number of clock cycles that must match for clock gating\n");
		log("        to be inserted (default: 1)\n");
		log("\n");
	}

	void execute(std::vector<std::string> args, RTLIL::Design *design) override
	{
		log_header(design, "Executing SAT_CLOCKGATE pass.\n");

		int threshold = 1;

		size_t argidx;
		for (argidx = 1; argidx < args.size(); argidx++) {
			if (args[argidx] == "-threshold" && argidx+1 < args.size()) {
				threshold = std::stoi(args[++argidx]);
				continue;
			}
			break;
		}
		extra_args(args, argidx, design);

		log("Using threshold: %d\n", threshold);

		// Dump all flip-flops to file
		dump_flipflops_to_file(design, "flip_flops.txt");

		for (auto module : design->selected_modules()) {
			log("Processing module %s...\n", log_id(module));
			// TODO: Implement SAT-based clock gating logic

			// Example: calling SAT pass
			// Pass::call(design, stringf("sat -verify -prove <signal> 1 %s", log_id(module)));
		}
	}
} SatClockgatePass;

PRIVATE_NAMESPACE_END