yosys/passes/equiv/equiv_simple.cc

280 lines
8.5 KiB
C++

/*
* 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/yosys.h"
#include "kernel/satgen.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct EquivSimpleWorker
{
Module *module;
Cell *equiv_cell;
SigMap &sigmap;
dict<SigBit, Cell*> &bit2driver;
ezDefaultSAT ez;
SatGen satgen;
int max_seq;
bool verbose;
EquivSimpleWorker(Cell *equiv_cell, SigMap &sigmap, dict<SigBit, Cell*> &bit2driver, int max_seq, bool verbose) :
module(equiv_cell->module), equiv_cell(equiv_cell), sigmap(sigmap),
bit2driver(bit2driver), satgen(&ez, &sigmap), max_seq(max_seq), verbose(verbose)
{
}
void find_input_cone(pool<SigBit> &next_seed, pool<Cell*> &cells_cone, pool<SigBit> &bits_cone, const pool<Cell*> &cells_stop, const pool<SigBit> &bits_stop, Cell *cell)
{
if (cells_cone.count(cell))
return;
cells_cone.insert(cell);
if (cells_stop.count(cell))
return;
for (auto &conn : cell->connections())
if (yosys_celltypes.cell_input(cell->type, conn.first))
for (auto bit : sigmap(conn.second)) {
if (cell->type.in("$dff", "$_DFF_P_", "$_DFF_N_")) {
if (!conn.first.in("\\CLK", "\\C"))
next_seed.insert(bit);
} else
find_input_cone(next_seed, cells_cone, bits_cone, cells_stop, bits_stop, bit);
}
}
void find_input_cone(pool<SigBit> &next_seed, pool<Cell*> &cells_cone, pool<SigBit> &bits_cone, const pool<Cell*> &cells_stop, const pool<SigBit> &bits_stop, SigBit bit)
{
if (bits_cone.count(bit))
return;
bits_cone.insert(bit);
if (bits_stop.count(bit))
return;
if (!bit2driver.count(bit))
return;
find_input_cone(next_seed, cells_cone, bits_cone, cells_stop, bits_stop, bit2driver.at(bit));
}
bool run()
{
SigBit bit_a = sigmap(equiv_cell->getPort("\\A")).to_single_sigbit();
SigBit bit_b = sigmap(equiv_cell->getPort("\\B")).to_single_sigbit();
int ez_a = satgen.importSigBit(bit_a, max_seq+1);
int ez_b = satgen.importSigBit(bit_b, max_seq+1);
ez.assume(ez.XOR(ez_a, ez_b));
pool<SigBit> seed_a = { bit_a };
pool<SigBit> seed_b = { bit_b };
if (verbose) {
log(" Trying to prove $equiv cell %s:\n", log_id(equiv_cell));
log(" A = %s, B = %s, Y = %s\n", log_signal(bit_a), log_signal(bit_b), log_signal(equiv_cell->getPort("\\Y")));
} else {
log(" Trying to prove $equiv for %s:", log_signal(equiv_cell->getPort("\\Y")));
}
int step = max_seq;
while (1)
{
pool<Cell*> no_stop_cells;
pool<SigBit> no_stop_bits;
pool<Cell*> full_cells_cone_a, full_cells_cone_b;
pool<SigBit> full_bits_cone_a, full_bits_cone_b;
pool<SigBit> next_seed_a, next_seed_b;
for (auto bit_a : seed_a)
find_input_cone(next_seed_a, full_cells_cone_a, full_bits_cone_a, no_stop_cells, no_stop_bits, bit_a);
next_seed_a.clear();
for (auto bit_b : seed_b)
find_input_cone(next_seed_b, full_cells_cone_b, full_bits_cone_b, no_stop_cells, no_stop_bits, bit_b);
next_seed_b.clear();
pool<Cell*> short_cells_cone_a, short_cells_cone_b;
pool<SigBit> short_bits_cone_a, short_bits_cone_b;
for (auto bit_a : seed_a)
find_input_cone(next_seed_a, short_cells_cone_a, short_bits_cone_a, full_cells_cone_b, full_bits_cone_b, bit_a);
next_seed_a.swap(seed_a);
for (auto bit_b : seed_b)
find_input_cone(next_seed_b, short_cells_cone_b, short_bits_cone_b, full_cells_cone_a, full_bits_cone_a, bit_b);
next_seed_b.swap(seed_b);
pool<Cell*> problem_cells;
problem_cells.insert(short_cells_cone_a.begin(), short_cells_cone_a.end());
problem_cells.insert(short_cells_cone_b.begin(), short_cells_cone_b.end());
if (verbose)
log(" Adding %d new cells to the problem (%d A, %d B, %d shared).\n",
GetSize(problem_cells), GetSize(short_cells_cone_a), GetSize(short_cells_cone_b),
(GetSize(short_cells_cone_a) + GetSize(short_cells_cone_b)) - GetSize(problem_cells));
for (auto cell : problem_cells)
if (!satgen.importCell(cell, step+1))
log_cmd_error("No SAT model available for cell %s (%s).\n", log_id(cell), log_id(cell->type));
if (verbose)
log(" Problem size at t=%d: %d literals, %d clauses\n", step, ez.numCnfVariables(), ez.numCnfClauses());
if (!ez.solve()) {
log(verbose ? " Proved equivalence! Marking $equiv cell as proven.\n" : " success!\n");
equiv_cell->setPort("\\B", equiv_cell->getPort("\\A"));
return true;
}
if (verbose)
log(" Failed to prove equivalence with sequence length %d.\n", max_seq - step);
if (--step < 0) {
if (verbose)
log(" Reached sequence limit.\n");
break;
}
if (seed_a.empty() && seed_b.empty()) {
if (verbose)
log(" No nets to continue in previous time step.\n");
break;
}
if (seed_a.empty()) {
if (verbose)
log(" No nets on A-side to continue in previous time step.\n");
break;
}
if (seed_b.empty()) {
if (verbose)
log(" No nets on B-side to continue in previous time step.\n");
break;
}
if (verbose) {
#if 0
log(" Continuing analysis in previous time step with the following nets:\n");
for (auto bit : seed_a)
log(" A: %s\n", log_signal(bit));
for (auto bit : seed_b)
log(" B: %s\n", log_signal(bit));
#else
log(" Continuing analysis in previous time step with %d A- and %d B-nets.\n", GetSize(seed_a), GetSize(seed_b));
#endif
}
}
if (!verbose)
log(" failed.\n");
return false;
}
};
struct EquivSimplePass : public Pass {
EquivSimplePass() : Pass("equiv_simple", "try proving simple $equiv instances") { }
virtual void help()
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" equiv_simple [options] [selection]\n");
log("\n");
log("This command tries to prove $equiv cells using a simple direct SAT approach.\n");
log("\n");
log(" -v\n");
log(" verbose output\n");
log("\n");
log(" -seq <N>\n");
log(" the max. number of time steps to be considered (default = 1)\n");
log("\n");
}
virtual void execute(std::vector<std::string> args, Design *design)
{
bool verbose = false;
int success_counter = 0;
int max_seq = 1;
log_header("Executing EQUIV_SIMPLE pass.\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-v") {
verbose = true;
continue;
}
if (args[argidx] == "-seq" && argidx+1 < args.size()) {
max_seq = atoi(args[++argidx].c_str());
continue;
}
break;
}
extra_args(args, argidx, design);
CellTypes ct;
ct.setup_internals();
ct.setup_stdcells();
for (auto module : design->selected_modules())
{
vector<pair<SigBit, Cell*>> unproven_equiv_cells;
for (auto cell : module->selected_cells())
if (cell->type == "$equiv" && cell->getPort("\\A") != cell->getPort("\\B"))
unproven_equiv_cells.push_back(pair<SigBit, Cell*>(cell->getPort("\\Y").to_single_sigbit(), cell));
if (unproven_equiv_cells.empty())
continue;
log("Found %d unproven $equiv cells in %s:\n", GetSize(unproven_equiv_cells), log_id(module));
SigMap sigmap(module);
dict<SigBit, Cell*> bit2driver;
for (auto cell : module->cells()) {
if (!ct.cell_known(cell->type) && !cell->type.in("$dff", "$_DFF_P_", "$_DFF_N_"))
continue;
for (auto &conn : cell->connections())
if (yosys_celltypes.cell_output(cell->type, conn.first))
for (auto bit : sigmap(conn.second))
bit2driver[bit] = cell;
}
std::sort(unproven_equiv_cells.begin(), unproven_equiv_cells.end());
for (auto it : unproven_equiv_cells) {
EquivSimpleWorker worker(it.second, sigmap, bit2driver, max_seq, verbose);
if (worker.run())
success_counter++;
}
}
log("Proved %d previously unproven $equiv cells.\n", success_counter);
}
} EquivSimplePass;
PRIVATE_NAMESPACE_END