SigSpec refactoring: change RTLIL::SigSpec::chunks() to be read-only, created interim...

[yosys.git] / passes / sat / eval.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.
 *
 */

// [[CITE]] VlogHammer Verilog Regression Test Suite
// http://www.clifford.at/yosys/vloghammer.html

#include "kernel/register.h"
#include "kernel/celltypes.h"
#include "kernel/consteval.h"
#include "kernel/sigtools.h"
#include "kernel/satgen.h"
#include "kernel/log.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <algorithm>

namespace {

/* this should only be used for regression testing of ConstEval -- see vloghammer */
struct BruteForceEquivChecker
{
        RTLIL::Module *mod1, *mod2;
        RTLIL::SigSpec mod1_inputs, mod1_outputs;
        RTLIL::SigSpec mod2_inputs, mod2_outputs;
        int counter, errors;
        bool ignore_x_mod1;

        void run_checker(RTLIL::SigSpec &inputs)
        {
                if (inputs.size() < mod1_inputs.size()) {
                        RTLIL::SigSpec inputs0 = inputs, inputs1 = inputs;
                        inputs0.append(RTLIL::Const(0, 1));
                        inputs1.append(RTLIL::Const(1, 1));
                        run_checker(inputs0);
                        run_checker(inputs1);
                        return;
                }

                inputs.optimize();

                ConstEval ce1(mod1), ce2(mod2);
                ce1.set(mod1_inputs, inputs.as_const());
                ce2.set(mod2_inputs, inputs.as_const());

                RTLIL::SigSpec sig1 = mod1_outputs, undef1;
                RTLIL::SigSpec sig2 = mod2_outputs, undef2;

                if (!ce1.eval(sig1, undef1))
                        log("Failed ConstEval of module 1 outputs at signal %s (input: %s = %s).\n",
                                        log_signal(undef1), log_signal(mod1_inputs), log_signal(inputs));
                if (!ce2.eval(sig2, undef2))
                        log("Failed ConstEval of module 2 outputs at signal %s (input: %s = %s).\n",
                                        log_signal(undef2), log_signal(mod1_inputs), log_signal(inputs));

                if (ignore_x_mod1) {
                        sig1.expand(), sig2.expand();
                        for (size_t i = 0; i < sig1.chunks().size(); i++)
                                if (sig1.chunks().at(i) == RTLIL::SigChunk(RTLIL::State::Sx))
                                        sig2.chunks_rw().at(i) = RTLIL::SigChunk(RTLIL::State::Sx);
                        sig1.optimize(), sig2.optimize();
                }

                if (sig1 != sig2) {
                        log("Found counter-example (ignore_x_mod1 = %s):\n", ignore_x_mod1 ? "active" : "inactive");
                        log("  Module 1:  %s = %s  =>  %s = %s\n", log_signal(mod1_inputs), log_signal(inputs), log_signal(mod1_outputs), log_signal(sig1));
                        log("  Module 2:  %s = %s  =>  %s = %s\n", log_signal(mod2_inputs), log_signal(inputs), log_signal(mod2_outputs), log_signal(sig2));
                        errors++;
                }

                counter++;
        }

        BruteForceEquivChecker(RTLIL::Module *mod1, RTLIL::Module *mod2, bool ignore_x_mod1) :
                        mod1(mod1), mod2(mod2), counter(0), errors(0), ignore_x_mod1(ignore_x_mod1)
        {
                log("Checking for equivialence (brute-force): %s vs %s\n", mod1->name.c_str(), mod2->name.c_str());
                for (auto &w : mod1->wires)
                {
                        RTLIL::Wire *wire1 = w.second;
                        if (wire1->port_id == 0)
                                continue;

                        if (mod2->wires.count(wire1->name) == 0)
                                log_cmd_error("Port %s in module 1 has no counterpart in module 2!\n", wire1->name.c_str());

                        RTLIL::Wire *wire2 = mod2->wires.at(wire1->name);
                        if (wire1->width != wire2->width || wire1->port_input != wire2->port_input || wire1->port_output != wire2->port_output)
                                log_cmd_error("Port %s in module 1 does not match its counterpart in module 2!\n", wire1->name.c_str());

                        if (wire1->port_input) {
                                mod1_inputs.append(wire1);
                                mod2_inputs.append(wire2);
                        } else {
                                mod1_outputs.append(wire1);
                                mod2_outputs.append(wire2);
                        }
                }

                RTLIL::SigSpec inputs;
                run_checker(inputs);
        }
};

/* this should only be used for regression testing of ConstEval -- see vloghammer */
struct VlogHammerReporter
{
        RTLIL::Design *design;
        std::vector<RTLIL::Module*> modules;
        std::vector<std::string> module_names;
        std::vector<RTLIL::IdString> inputs;
        std::vector<int> input_widths;
        std::vector<RTLIL::Const> patterns;
        int total_input_width;

        std::vector<std::string> split(std::string text, const char *delim)
        {
                std::vector<std::string> list;
                char *p = strdup(text.c_str());
                char *t = strtok(p, delim);
                while (t != NULL) {
                        list.push_back(t);
                        t = strtok(NULL, delim);
                }
                free(p);
                return list;
        }

        void sat_check(RTLIL::Module *module, RTLIL::SigSpec recorded_set_vars, RTLIL::Const recorded_set_vals, RTLIL::SigSpec expected_y, bool model_undef)
        {
                log("Verifying SAT model (%s)..\n", model_undef ? "with undef" : "without undef");

                ezDefaultSAT ez;
                SigMap sigmap(module);
                SatGen satgen(&ez, &sigmap);
                satgen.model_undef = model_undef;

                for (auto &c : module->cells)
                        if (!satgen.importCell(c.second))
                                log_error("Failed to import cell %s (type %s) to SAT database.\n", RTLIL::id2cstr(c.first), RTLIL::id2cstr(c.second->type));

                ez.assume(satgen.signals_eq(recorded_set_vars, recorded_set_vals));

                std::vector<int> y_vec = satgen.importDefSigSpec(module->wires.at("\\y"));
                std::vector<bool> y_values;

                if (model_undef) {
                        std::vector<int> y_undef_vec = satgen.importUndefSigSpec(module->wires.at("\\y"));
                        y_vec.insert(y_vec.end(), y_undef_vec.begin(), y_undef_vec.end());
                }

                log("  Created SAT problem with %d variables and %d clauses.\n",
                                ez.numCnfVariables(), ez.numCnfClauses());

                if (!ez.solve(y_vec, y_values))
                        log_error("Failed to find solution to SAT problem.\n");

                expected_y.expand();
                for (int i = 0; i < expected_y.size(); i++) {
                        RTLIL::State solution_bit = y_values.at(i) ? RTLIL::State::S1 : RTLIL::State::S0;
                        RTLIL::State expected_bit = expected_y.chunks().at(i).data.bits.at(0);
                        if (model_undef) {
                                if (y_values.at(expected_y.size()+i))
                                        solution_bit = RTLIL::State::Sx;
                        } else {
                                if (expected_bit == RTLIL::State::Sx)
                                        continue;
                        }
                        if (solution_bit != expected_bit) {
                                std::string sat_bits, rtl_bits;
                                for (int k = expected_y.size()-1; k >= 0; k--) {
                                        if (model_undef && y_values.at(expected_y.size()+k))
                                                sat_bits += "x";
                                        else
                                                sat_bits += y_values.at(k) ? "1" : "0";
                                        rtl_bits += expected_y.chunks().at(k).data.bits.at(0) == RTLIL::State::Sx ? "x" :
                                                        expected_y.chunks().at(k).data.bits.at(0) == RTLIL::State::S1 ? "1" : "0";
                                }
                                log_error("Found error in SAT model: y[%d] = %s, should be %s:\n   SAT: %s\n   RTL: %s\n        %*s^\n",
                                                int(i), log_signal(solution_bit), log_signal(expected_bit),
                                                sat_bits.c_str(), rtl_bits.c_str(), expected_y.size()-i-1, "");
                        }
                }

                if (model_undef)
                {
                        std::vector<int> cmp_vars;
                        std::vector<bool> cmp_vals;

                        std::vector<bool> y_undef(y_values.begin() + expected_y.size(), y_values.end());

                        for (int i = 0; i < expected_y.size(); i++)
                                if (y_undef.at(i))
                                {
                                        log("    Toggling undef bit %d to test undef gating.\n", i);
                                        if (!ez.solve(y_vec, y_values, ez.IFF(y_vec.at(i), y_values.at(i) ? ez.FALSE : ez.TRUE)))
                                                log_error("Failed to find solution with toggled bit!\n");

                                        cmp_vars.push_back(y_vec.at(expected_y.size() + i));
                                        cmp_vals.push_back(true);
                                }
                                else
                                {
                                        cmp_vars.push_back(y_vec.at(i));
                                        cmp_vals.push_back(y_values.at(i));

                                        cmp_vars.push_back(y_vec.at(expected_y.size() + i));
                                        cmp_vals.push_back(false);
                                }

                        log("    Testing if SAT solution is unique.\n");
                        ez.assume(ez.vec_ne(cmp_vars, ez.vec_const(cmp_vals)));
                        if (ez.solve(y_vec, y_values))
                                log_error("Found two distinct solutions to SAT problem.\n");
                }
                else
                {
                        log("    Testing if SAT solution is unique.\n");
                        ez.assume(ez.vec_ne(y_vec, ez.vec_const(y_values)));
                        if (ez.solve(y_vec, y_values))
                                log_error("Found two distinct solutions to SAT problem.\n");
                }

                log("  SAT model verified.\n");
        }

        void run()
        {
                for (int idx = 0; idx < int(patterns.size()); idx++)
                {
                        log("Creating report for pattern %d: %s\n", idx, log_signal(patterns[idx]));
                        std::string input_pattern_list;
                        RTLIL::SigSpec rtl_sig;

                        for (int mod = 0; mod < int(modules.size()); mod++)
                        {
                                RTLIL::SigSpec recorded_set_vars;
                                RTLIL::Const recorded_set_vals;
                                RTLIL::Module *module = modules[mod];
                                std::string module_name = module_names[mod].c_str();
                                ConstEval ce(module);

                                std::vector<RTLIL::State> bits(patterns[idx].bits.begin(), patterns[idx].bits.begin() + total_input_width);
                                for (int i = 0; i < int(inputs.size()); i++) {
                                        RTLIL::Wire *wire = module->wires.at(inputs[i]);
                                        for (int j = input_widths[i]-1; j >= 0; j--) {
                                                ce.set(RTLIL::SigSpec(wire, 1, j), bits.back());
                                                recorded_set_vars.append(RTLIL::SigSpec(wire, 1, j));
                                                recorded_set_vals.bits.push_back(bits.back());
                                                bits.pop_back();
                                        }
                                        if (module == modules.front()) {
                                                RTLIL::SigSpec sig(wire);
                                                if (!ce.eval(sig))
                                                        log_error("Can't read back value for port %s!\n", RTLIL::id2cstr(inputs[i]));
                                                input_pattern_list += stringf(" %s", sig.as_const().as_string().c_str());
                                                log("++PAT++ %d %s %s #\n", idx, RTLIL::id2cstr(inputs[i]), sig.as_const().as_string().c_str());
                                        }
                                }

                                if (module->wires.count("\\y") == 0)
                                        log_error("No output wire (y) found in module %s!\n", RTLIL::id2cstr(module->name));

                                RTLIL::SigSpec sig(module->wires.at("\\y"));
                                RTLIL::SigSpec undef;

                                while (!ce.eval(sig, undef)) {
                                        // log_error("Evaluation of y in module %s failed: sig=%s, undef=%s\n", RTLIL::id2cstr(module->name), log_signal(sig), log_signal(undef));
                                        log("Warning: Setting signal %s in module %s to undef.\n", log_signal(undef), RTLIL::id2cstr(module->name));
                                        ce.set(undef, RTLIL::Const(RTLIL::State::Sx, undef.size()));
                                }

                                log("++VAL++ %d %s %s #\n", idx, module_name.c_str(), sig.as_const().as_string().c_str());

                                if (module_name == "rtl") {
                                        rtl_sig = sig;
                                        rtl_sig.expand();
                                        sat_check(module, recorded_set_vars, recorded_set_vals, sig, false);
                                        sat_check(module, recorded_set_vars, recorded_set_vals, sig, true);
                                } else if (rtl_sig.size() > 0) {
                                        sig.expand();
                                        if (rtl_sig.size() != sig.size())
                                                log_error("Output (y) has a different width in module %s compared to rtl!\n", RTLIL::id2cstr(module->name));
                                        for (int i = 0; i < sig.size(); i++)
                                                if (rtl_sig.chunks().at(i).data.bits.at(0) == RTLIL::State::Sx)
                                                        sig.chunks_rw().at(i).data.bits.at(0) = RTLIL::State::Sx;
                                }

                                log("++RPT++ %d%s %s %s\n", idx, input_pattern_list.c_str(), sig.as_const().as_string().c_str(), module_name.c_str());
                        }

                        log("++RPT++ ----\n");
                }
                log("++OK++\n");
        }

        VlogHammerReporter(RTLIL::Design *design, std::string module_prefix, std::string module_list, std::string input_list, std::string pattern_list) : design(design)
        {
                for (auto name : split(module_list, ",")) {
                        RTLIL::IdString esc_name = RTLIL::escape_id(module_prefix + name);
                        if (design->modules.count(esc_name) == 0)
                                log_error("Can't find module %s in current design!\n", name.c_str());
                        log("Using module %s (%s).\n", esc_name.c_str(), name.c_str());
                        modules.push_back(design->modules.at(esc_name));
                        module_names.push_back(name);
                }

                total_input_width = 0;
                for (auto name : split(input_list, ",")) {
                        int width = -1;
                        RTLIL::IdString esc_name = RTLIL::escape_id(name);
                        for (auto mod : modules) {
                                if (mod->wires.count(esc_name) == 0)
                                        log_error("Can't find input %s in module %s!\n", name.c_str(), RTLIL::id2cstr(mod->name));
                                RTLIL::Wire *port = mod->wires.at(esc_name);
                                if (!port->port_input || port->port_output)
                                        log_error("Wire %s in module %s is not an input!\n", name.c_str(), RTLIL::id2cstr(mod->name));
                                if (width >= 0 && width != port->width)
                                        log_error("Port %s has different sizes in the different modules!\n", name.c_str());
                                width = port->width;
                        }
                        log("Using input port %s with width %d.\n", esc_name.c_str(), width);
                        inputs.push_back(esc_name);
                        input_widths.push_back(width);
                        total_input_width += width;
                }

                for (auto pattern : split(pattern_list, ",")) {
                        RTLIL::SigSpec sig;
                        bool invert_pattern = false;
                        if (pattern.size() > 0 && pattern[0] == '~') {
                                invert_pattern = true;
                                pattern = pattern.substr(1);
                        }
                        if (!RTLIL::SigSpec::parse(sig, NULL, pattern) || !sig.is_fully_const())
                                log_error("Failed to parse pattern %s!\n", pattern.c_str());
                        if (sig.size() < total_input_width)
                                log_error("Pattern %s is to short!\n", pattern.c_str());
                        patterns.push_back(sig.as_const());
                        if (invert_pattern) {
                                for (auto &bit : patterns.back().bits)
                                        if (bit == RTLIL::State::S0)
                                                bit = RTLIL::State::S1;
                                        else if (bit == RTLIL::State::S1)
                                                bit = RTLIL::State::S0;
                        }
                        log("Using pattern %s.\n", patterns.back().as_string().c_str());
                }
        }
};

} /* namespace */

struct EvalPass : public Pass {
        EvalPass() : Pass("eval", "evaluate the circuit given an input") { }
        virtual void help()
        {
                //   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
                log("\n");
                log("    eval [options] [selection]\n");
                log("\n");
                log("This command evaluates the value of a signal given the value of all required\n");
                log("inputs.\n");
                log("\n");
                log("    -set <signal> <value>\n");
                log("        set the specified signal to the specified value.\n");
                log("\n");
                log("    -set-undef\n");
                log("        set all unspecified source signals to undef (x)\n");
                log("\n");
                log("    -table <signal>\n");
                log("        create a truth table using the specified input signals\n");
                log("\n");
                log("    -show <signal>\n");
                log("        show the value for the specified signal. if no -show option is passed\n");
                log("        then all output ports of the current module are used.\n");
                log("\n");
        }
        virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
        {
                std::vector<std::pair<std::string, std::string>> sets;
                std::vector<std::string> shows, tables;
                bool set_undef = false;

                log_header("Executing EVAL pass (evaluate the circuit given an input).\n");

                size_t argidx;
                for (argidx = 1; argidx < args.size(); argidx++) {
                        if (args[argidx] == "-set" && argidx+2 < args.size()) {
                                std::string lhs = args[++argidx].c_str();
                                std::string rhs = args[++argidx].c_str();
                                sets.push_back(std::pair<std::string, std::string>(lhs, rhs));
                                continue;
                        }
                        if (args[argidx] == "-set-undef") {
                                set_undef = true;
                                continue;
                        }
                        if (args[argidx] == "-show" && argidx+1 < args.size()) {
                                shows.push_back(args[++argidx]);
                                continue;
                        }
                        if (args[argidx] == "-table" && argidx+1 < args.size()) {
                                tables.push_back(args[++argidx]);
                                continue;
                        }
                        if ((args[argidx] == "-brute_force_equiv_checker" || args[argidx] == "-brute_force_equiv_checker_x") && argidx+3 == args.size()) {
                                /* this should only be used for regression testing of ConstEval -- see vloghammer */
                                std::string mod1_name = RTLIL::escape_id(args[++argidx]);
                                std::string mod2_name = RTLIL::escape_id(args[++argidx]);
                                if (design->modules.count(mod1_name) == 0)
                                        log_error("Can't find module `%s'!\n", mod1_name.c_str());
                                if (design->modules.count(mod2_name) == 0)
                                        log_error("Can't find module `%s'!\n", mod2_name.c_str());
                                BruteForceEquivChecker checker(design->modules.at(mod1_name), design->modules.at(mod2_name), args[argidx-2] == "-brute_force_equiv_checker_x");
                                if (checker.errors > 0)
                                        log_cmd_error("Modules are not equivialent!\n");
                                log("Verified %s = %s (using brute-force check on %d cases).\n",
                                                mod1_name.c_str(), mod2_name.c_str(), checker.counter);
                                return;
                        }
                        if (args[argidx] == "-vloghammer_report" && argidx+5 == args.size()) {
                                /* this should only be used for regression testing of ConstEval -- see vloghammer */
                                std::string module_prefix = args[++argidx];
                                std::string module_list = args[++argidx];
                                std::string input_list = args[++argidx];
                                std::string pattern_list = args[++argidx];
                                VlogHammerReporter reporter(design, module_prefix, module_list, input_list, pattern_list);
                                reporter.run();
                                return;
                        }
                        break;
                }
                extra_args(args, argidx, design);

                RTLIL::Module *module = NULL;
                for (auto &mod_it : design->modules)
                        if (design->selected(mod_it.second)) {
                                if (module)
                                        log_cmd_error("Only one module must be selected for the EVAL pass! (selected: %s and %s)\n",
                                                        RTLIL::id2cstr(module->name), RTLIL::id2cstr(mod_it.first));
                                module = mod_it.second;
                        }
                if (module == NULL) 
                        log_cmd_error("Can't perform EVAL on an empty selection!\n");

                ConstEval ce(module);

                for (auto &it : sets) {
                        RTLIL::SigSpec lhs, rhs;
                        if (!RTLIL::SigSpec::parse_sel(lhs, design, module, it.first))
                                log_cmd_error("Failed to parse lhs set expression `%s'.\n", it.first.c_str());
                        if (!RTLIL::SigSpec::parse_rhs(lhs, rhs, module, it.second))
                                log_cmd_error("Failed to parse rhs set expression `%s'.\n", it.second.c_str());
                        if (!rhs.is_fully_const())
                                log_cmd_error("Right-hand-side set expression `%s' is not constant.\n", it.second.c_str());
                        if (lhs.size() != rhs.size())
                                log_cmd_error("Set expression with different lhs and rhs sizes: %s (%s, %d bits) vs. %s (%s, %d bits)\n",
                                                it.first.c_str(), log_signal(lhs), lhs.size(), it.second.c_str(), log_signal(rhs), rhs.size());
                        ce.set(lhs, rhs.as_const());
                }

                if (shows.size() == 0) {
                        for (auto &it : module->wires)
                                if (it.second->port_output)
                                        shows.push_back(it.second->name);
                }

                if (tables.empty())
                {
                        for (auto &it : shows) {
                                RTLIL::SigSpec signal, value, undef;
                                if (!RTLIL::SigSpec::parse_sel(signal, design, module, it))
                                        log_cmd_error("Failed to parse show expression `%s'.\n", it.c_str());
                                signal.optimize();
                                value = signal;
                                if (set_undef) {
                                        while (!ce.eval(value, undef)) {
                                                log("Failed to evaluate signal %s: Missing value for %s. -> setting to undef\n", log_signal(signal), log_signal(undef));
                                                ce.set(undef, RTLIL::Const(RTLIL::State::Sx, undef.size()));
                                                undef = RTLIL::SigSpec();
                                        }
                                        log("Eval result: %s = %s.\n", log_signal(signal), log_signal(value));
                                } else {
                                        if (!ce.eval(value, undef))
                                                log("Failed to evaluate signal %s: Missing value for %s.\n", log_signal(signal), log_signal(undef));
                                        else
                                                log("Eval result: %s = %s.\n", log_signal(signal), log_signal(value));
                                }
                        }
                }
                else
                {
                        RTLIL::SigSpec tabsigs, signal, value, undef;
                        std::vector<std::vector<std::string>> tab;
                        int tab_sep_colidx = 0;

                        for (auto &it : shows) {
                                RTLIL::SigSpec sig;
                                if (!RTLIL::SigSpec::parse_sel(sig, design, module, it))
                                        log_cmd_error("Failed to parse show expression `%s'.\n", it.c_str());
                                signal.append(sig);
                        }

                        for (auto &it : tables) {
                                RTLIL::SigSpec sig;
                                if (!RTLIL::SigSpec::parse_sel(sig, design, module, it))
                                        log_cmd_error("Failed to parse table expression `%s'.\n", it.c_str());
                                tabsigs.append(sig);
                        }

                        std::vector<std::string> tab_line;
                        for (auto &c : tabsigs.chunks())
                                tab_line.push_back(log_signal(c));
                        tab_sep_colidx = tab_line.size();
                        for (auto &c : signal.chunks())
                                tab_line.push_back(log_signal(c));
                        tab.push_back(tab_line);
                        tab_line.clear();

                        RTLIL::Const tabvals(0, tabsigs.size());
                        do
                        {
                                ce.push();
                                ce.set(tabsigs, tabvals);
                                value = signal;

                                RTLIL::SigSpec this_undef;
                                while (!ce.eval(value, this_undef)) {
                                        if (!set_undef) {
                                                log("Failed to evaluate signal %s at %s = %s: Missing value for %s.\n", log_signal(signal),
                                                                log_signal(tabsigs), log_signal(tabvals), log_signal(this_undef));
                                                return;
                                        }
                                        ce.set(this_undef, RTLIL::Const(RTLIL::State::Sx, this_undef.size()));
                                        undef.append(this_undef);
                                        this_undef = RTLIL::SigSpec();
                                }

                                int pos = 0;
                                for (auto &c : tabsigs.chunks()) {
                                        tab_line.push_back(log_signal(RTLIL::SigSpec(tabvals).extract(pos, c.width)));
                                        pos += c.width;
                                }

                                pos = 0;
                                for (auto &c : signal.chunks()) {
                                        tab_line.push_back(log_signal(value.extract(pos, c.width)));
                                        pos += c.width;
                                }

                                tab.push_back(tab_line);
                                tab_line.clear();
                                ce.pop();

                                tabvals = RTLIL::const_add(tabvals, RTLIL::Const(1), false, false, tabvals.bits.size());
                        }
                        while (tabvals.as_bool());

                        std::vector<int> tab_column_width;
                        for (auto &row : tab) {
                                if (tab_column_width.size() < row.size())
                                        tab_column_width.resize(row.size());
                                for (size_t i = 0; i < row.size(); i++)
                                        tab_column_width[i] = std::max(tab_column_width[i], int(row[i].size()));
                        }

                        log("\n");
                        bool first = true;
                        for (auto &row : tab) {
                                for (size_t i = 0; i < row.size(); i++) {
                                        int k = int(i) < tab_sep_colidx ? tab_sep_colidx - i - 1 : i;
                                        log(" %s%*s", k == tab_sep_colidx ? "| " : "", tab_column_width[k], row[k].c_str());
                                }
                                log("\n");
                                if (first) {
                                        for (size_t i = 0; i < row.size(); i++) {
                                                int k = int(i) < tab_sep_colidx ? tab_sep_colidx - i - 1 : i;
                                                log(" %s", k == tab_sep_colidx ? "| " : "");
                                                for (int j = 0; j < tab_column_width[k]; j++)
                                                        log("-");
                                        }
                                        log("\n");
                                        first = false;
                                }
                        }

                        log("\n");
                        if (undef.size() > 0) {
                                undef.sort_and_unify();
                                log("Assumend undef (x) value for the following singals: %s\n\n", log_signal(undef));
                        }
                }
        }
} EvalPass;