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/*
* 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/sigtools.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct EquivStructWorker
{
Module *module;
SigMap sigmap;
SigMap equiv_bits;
bool mode_icells;
int merge_count;
dict<IdString, pool<IdString>> cells_by_type;
void handle_cell_pair(Cell *cell_a, Cell *cell_b)
{
if (cell_a->parameters != cell_b->parameters)
return;
bool merge_this_cells = false;
bool found_diff_inputs = false;
vector<SigSpec> inputs_a, inputs_b;
for (auto &port_a : cell_a->connections())
{
SigSpec bits_a = equiv_bits(port_a.second);
SigSpec bits_b = equiv_bits(cell_b->getPort(port_a.first));
if (GetSize(bits_a) != GetSize(bits_b))
return;
if (cell_a->output(port_a.first)) {
for (int i = 0; i < GetSize(bits_a); i++)
if (bits_a[i] == bits_b[i])
merge_this_cells = true;
} else {
SigSpec diff_bits_a, diff_bits_b;
for (int i = 0; i < GetSize(bits_a); i++)
if (bits_a[i] != bits_b[i]) {
diff_bits_a.append(bits_a[i]);
diff_bits_b.append(bits_b[i]);
}
if (!diff_bits_a.empty()) {
inputs_a.push_back(diff_bits_a);
inputs_b.push_back(diff_bits_b);
found_diff_inputs = true;
}
}
}
if (!found_diff_inputs)
merge_this_cells = true;
if (merge_this_cells)
{
SigMap merged_map;
log(" Merging cells %s and %s.\n", log_id(cell_a), log_id(cell_b));
merge_count++;
for (int i = 0; i < GetSize(inputs_a); i++) {
SigSpec &sig_a = inputs_a[i], &sig_b = inputs_b[i];
SigSpec sig_y = module->addWire(NEW_ID, GetSize(sig_a));
log(" A: %s, B: %s, Y: %s\n", log_signal(sig_a), log_signal(sig_b), log_signal(sig_y));
module->addEquiv(NEW_ID, sig_a, sig_b, sig_y);
merged_map.add(sig_a, sig_y);
merged_map.add(sig_b, sig_y);
}
std::vector<IdString> outport_names, inport_names;
for (auto &port_a : cell_a->connections())
if (cell_a->output(port_a.first))
outport_names.push_back(port_a.first);
else
inport_names.push_back(port_a.first);
for (auto &pn : inport_names)
cell_a->setPort(pn, merged_map(equiv_bits(cell_a->getPort(pn))));
for (auto &pn : outport_names) {
SigSpec sig_a = cell_a->getPort(pn);
SigSpec sig_b = cell_b->getPort(pn);
module->connect(sig_b, sig_a);
sigmap.add(sig_b, sig_a);
equiv_bits.add(sig_b, sig_a);
}
module->remove(cell_b);
}
}
EquivStructWorker(Module *module, bool mode_icells) :
module(module), sigmap(module), equiv_bits(module), mode_icells(mode_icells), merge_count(0)
{
log(" Starting new iteration.\n");
for (auto cell : module->selected_cells())
if (cell->type == "$equiv") {
equiv_bits.add(sigmap(cell->getPort("\\A")), sigmap(cell->getPort("\\B")));
cells_by_type[cell->type].insert(cell->name);
} else
if (module->design->selected(module, cell)) {
if (mode_icells || module->design->module(cell->type))
cells_by_type[cell->type].insert(cell->name);
}
for (auto &it : cells_by_type)
{
if (it.second.size() <= 1)
continue;
log(" Merging %s cells..\n", log_id(it.first));
// FIXME: O(n^2)
for (auto cell_name_a : it.second)
for (auto cell_name_b : it.second)
if (cell_name_a < cell_name_b) {
Cell *cell_a = module->cell(cell_name_a);
Cell *cell_b = module->cell(cell_name_b);
if (cell_a && cell_b)
handle_cell_pair(cell_a, cell_b);
}
}
}
};
struct EquivStructPass : public Pass {
EquivStructPass() : Pass("equiv_struct", "structural equivalence checking") { }
virtual void help()
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" equiv_struct [options] [selection]\n");
log("\n");
log("This command adds additional $equiv cells based on the assumption that the\n");
log("gold and gate circuit are structurally equivalent. Note that this can introduce\n");
log("bad $equiv cells in cases where the netlists are not structurally equivalent,\n");
log("for example when analyzing circuits with cells with commutative inputs. This\n");
log("command will also de-duplicate gates.\n");
log("\n");
log(" -icells\n");
log(" by default, the internal RTL and gate cell types are ignored. add\n");
log(" this option to also process those cell types with this command.\n");
log("\n");
}
virtual void execute(std::vector<std::string> args, Design *design)
{
bool mode_icells = false;
log_header("Executing EQUIV_STRUCT pass.\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-icells") {
mode_icells = true;
continue;
}
break;
}
extra_args(args, argidx, design);
for (auto module : design->selected_modules()) {
log("Running equiv_struct on module %s:", log_id(module));
while (1) {
EquivStructWorker worker(module, mode_icells);
if (worker.merge_count == 0)
break;
}
}
}
} EquivStructPass;
PRIVATE_NAMESPACE_END
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