yosys/passes/opt/opt.cc

/*
 *  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/log.h"
#include <stdlib.h>
#include <stdio.h>

struct OptPass : public Pass {
	OptPass() : Pass("opt", "perform simple optimizations") { }
	virtual void help()
	{
		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
		log("\n");
		log("    opt [options] [selection]\n");
		log("\n");
		log("This pass calls all the other opt_* passes in a useful order. This performs\n");
		log("a series of trivial optimizations and cleanups. This pass executes the other\n");
		log("passes in the following order:\n");
		log("\n");
		log("    opt_const [-mux_undef] [-mux_bool] [-undriven] [-fine] [-keepdc]\n");
		log("    opt_share -nomux\n");
		log("\n");
		log("    do\n");
		log("        opt_muxtree\n");
		log("        opt_reduce [-fine]\n");
		log("        opt_share\n");
		log("        opt_rmdff\n");
		log("        opt_clean [-purge]\n");
		log("        opt_const [-mux_undef] [-mux_bool] [-undriven] [-fine] [-keepdc]\n");
		log("    while <changed design>\n");
		log("\n");
		log("When called with -fast the following script is used instead:\n");
		log("\n");
		log("    do\n");
		log("        opt_const [-mux_undef] [-mux_bool] [-undriven] [-fine] [-keepdc]\n");
		log("        opt_share\n");
		log("        opt_rmdff\n");
		log("        opt_clean [-purge]\n");
		log("    while <changed design in opt_rmdff>\n");
		log("\n");
		log("Note: Options in square brackets (such as [-keepdc]) are passed through to\n");
		log("the opt_* commands when given to 'opt'.\n");
		log("\n");
		log("\n");
	}
	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
	{
		std::string opt_clean_args;
		std::string opt_const_args;
		std::string opt_reduce_args;
		bool fast_mode = false;

		log_header("Executing OPT pass (performing simple optimizations).\n");
		log_push();

		size_t argidx;
		for (argidx = 1; argidx < args.size(); argidx++) {
			if (args[argidx] == "-purge") {
				opt_clean_args += " -purge";
				continue;
			}
			if (args[argidx] == "-mux_undef") {
				opt_const_args += " -mux_undef";
				continue;
			}
			if (args[argidx] == "-mux_bool") {
				opt_const_args += " -mux_bool";
				continue;
			}
			if (args[argidx] == "-undriven") {
				opt_const_args += " -undriven";
				continue;
			}
			if (args[argidx] == "-fine") {
				opt_const_args += " -fine";
				opt_reduce_args += " -fine";
				continue;
			}
			if (args[argidx] == "-keepdc") {
				opt_const_args += " -keepdc";
				continue;
			}
			if (args[argidx] == "-fast") {
				fast_mode = true;
				continue;
			}
			break;
		}
		extra_args(args, argidx, design);

		if (fast_mode)
		{
			while (1) {
				Pass::call(design, "opt_const" + opt_const_args);
				Pass::call(design, "opt_share");
				design->scratchpad_unset("opt.did_something");
				Pass::call(design, "opt_rmdff");
				if (design->scratchpad_get_bool("opt.did_something") == false)
					break;
				Pass::call(design, "opt_clean" + opt_clean_args);
				log_header("Rerunning OPT passes. (Removed registers in this run.)\n");
			}
			Pass::call(design, "opt_clean" + opt_clean_args);
		}
		else
		{
			Pass::call(design, "opt_const" + opt_const_args);
			Pass::call(design, "opt_share -nomux");
			while (1) {
				design->scratchpad_unset("opt.did_something");
				Pass::call(design, "opt_muxtree");
				Pass::call(design, "opt_reduce" + opt_reduce_args);
				Pass::call(design, "opt_share");
				Pass::call(design, "opt_rmdff");
				Pass::call(design, "opt_clean" + opt_clean_args);
				Pass::call(design, "opt_const" + opt_const_args);
				if (design->scratchpad_get_bool("opt.did_something") == false)
					break;
				log_header("Rerunning OPT passes. (Maybe there is more to do..)\n");
			}
		}

		log_header(fast_mode ? "Finished fast OPT passes." : "Finished OPT passes. (There is nothing left to do.)\n");
		log_pop();
	}
} OptPass;