cellmatch: New pass

This commit is contained in:
Martin Povišer 2024-03-27 23:54:51 +01:00 committed by Emil J. Tywoniak
parent 2631c7e918
commit 86e1080f05
2 changed files with 341 additions and 0 deletions

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@ -48,6 +48,7 @@ OBJS += passes/techmap/dfflegalize.o
OBJS += passes/techmap/dffunmap.o
OBJS += passes/techmap/flowmap.o
OBJS += passes/techmap/extractinv.o
OBJS += passes/techmap/cellmatch.o
endif
ifeq ($(DISABLE_SPAWN),0)

340
passes/techmap/cellmatch.cc Normal file
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@ -0,0 +1,340 @@
#include "kernel/celltypes.h"
#include "kernel/register.h"
#include "kernel/rtlil.h"
#include "kernel/sigtools.h"
#include "kernel/utils.h"
#include <algorithm>
USING_YOSYS_NAMESPACE
YOSYS_NAMESPACE_BEGIN
// return module's inputs in canonical order
SigSpec module_inputs(Module *m)
{
SigSpec ret;
for (auto port : m->ports) {
Wire *w = m->wire(port);
if (!w->port_input)
continue;
if (w->width != 1)
log_error("Unsupported wide port (%s) of non-unit width found in module %s.\n",
log_id(w), log_id(m));
ret.append(w);
}
return ret;
}
// return module's outputs in canonical order
SigSpec module_outputs(Module *m)
{
SigSpec ret;
for (auto port : m->ports) {
Wire *w = m->wire(port);
if (!w->port_output)
continue;
if (w->width != 1)
log_error("Unsupported wide port (%s) of non-unit width found in module %s.\n",
log_id(w), log_id(m));
ret.append(w);
}
return ret;
}
uint64_t permute_lut(uint64_t lut, const std::vector<int> &varmap)
{
int k = varmap.size();
uint64_t ret = 0;
for (int j = 0; j < 1 << k; j++) {
int m = 0;
for (int l = 0; l < k; l++)
if (j & 1 << l)
m |= 1 << varmap[l];
if (lut & 1 << m)
ret |= 1 << j;
}
return ret;
}
uint64_t p_class(int k, uint64_t lut)
{
std::vector<int> map;
for (int j = 0; j < k; j++)
map.push_back(j);
uint64_t repr = ~(uint64_t) 0;
std::vector<int> repr_vars;
while (true) {
uint64_t perm = permute_lut(lut, map);
if (perm <= repr) {
repr = perm;
repr_vars = map;
}
if (!std::next_permutation(map.begin(), map.end()))
break;
}
return repr;
}
bool derive_module_luts(Module *m, std::vector<uint64_t> &luts)
{
SigMap sigmap(m);
CellTypes ff_types;
ff_types.setup_stdcells_mem();
dict<SigBit, Cell*> driver;
for (auto cell : m->selected_cells()) {
if (cell->type.in(ID($specify2), ID($specify3), ID($specrule)))
continue;
if (ff_types.cell_known(cell->type)) {
log("Ignoring module '%s' which isn't purely combinational.\n", log_id(m));
return false;
}
if (!cell->type.in(ID($_NOT_), ID($_AND_)))
log_error("Unsupported cell in module '%s': %s of type %s\n",
log_id(m), log_id(cell), log_id(cell->type));
driver[sigmap(cell->getPort(ID::Y))] = cell;
}
TopoSort<Cell*> sort;
for (auto cell : m->cells())
if (cell->type.in(ID($_NOT_), ID($_AND_))) {
sort.node(cell);
SigSpec inputs = cell->type == ID($_AND_)
? SigSpec({cell->getPort(ID::B), cell->getPort(ID::A)})
: cell->getPort(ID::A);
for (auto bit : sigmap(inputs))
if (driver.count(bit))
sort.edge(driver.at(bit), cell);
}
if (!sort.sort())
log_error("Module %s contains combinational loops.\n", log_id(m));
dict<SigBit, uint64_t> states;
states[State::S0] = 0;
states[State::S1] = ~(uint64_t) 1;
{
uint64_t sieves[6] = {
0xaaaaaaaaaaaaaaaa,
0xcccccccccccccccc,
0xf0f0f0f0f0f0f0f0,
0xff00ff00ff00ff00,
0xffff0000ffff0000,
0xffffffff00000000,
};
SigSpec inputs = sigmap(module_inputs(m));
if (inputs.size() > 6) {
log_warning("Skipping module %s with more than 6 inputs bits.\n", log_id(m));
return false;
}
for (int i = 0; i < inputs.size(); i++)
states[inputs[i]] = sieves[i] & ((((uint64_t) 1) << (1 << inputs.size())) - 1);
}
for (auto cell : sort.sorted) {
if (cell->type.in(ID($specify2), ID($specify3), ID($specrule)))
continue;
if (cell->type == ID($_AND_)) {
SigSpec a = sigmap(cell->getPort(ID::A));
SigSpec b = sigmap(cell->getPort(ID::B));
if (!states.count(a) || !states.count(b))
log_error("Cell %s in module %s sources an undriven wire!",
log_id(cell), log_id(m));
states[sigmap(cell->getPort(ID::Y))] = \
states.at(a) & states.at(b);
} else if (cell->type == ID($_NOT_)) {
SigSpec a = sigmap(cell->getPort(ID::A));
if (!states.count(a))
log_error("Cell %s in module %s sources an undriven wire!",
log_id(cell), log_id(m));
states[sigmap(cell->getPort(ID::Y))] = ~states.at(a);
} else {
log_abort();
}
}
for (auto bit : module_outputs(m)) {
if (!states.count(sigmap(bit)))
log_error("Output port %s in module %s is undriven!",
log_signal(bit), log_id(m));
luts.push_back(states.at(sigmap(bit)));
}
return true;
}
struct CellmatchPass : Pass {
CellmatchPass() : Pass("cellmatch", "match cells to their targets in cell library") {}
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" cellmatch -lib <design> [module selection]\n");
log("\n");
log("This pass identifies functionally equivalent counterparts between each of the\n");
log("selected modules and a module from the secondary design <design>. For every such\n");
log("correspondence found, a techmap rule is generated for mapping instances of the\n");
log("former to instances of the latter. This techmap rule is saved in yet another\n");
log("design called '$cellmatch_map', which is created if non-existent.\n");
log("\n");
log("This pass restricts itself to combinational modules which must be modeled with an\n");
log("and-inverter graph. Run 'aigmap' first if necessary. Modules are functionally\n");
log("equivalent as long as their truth tables are identical upto a permutation of\n");
log("inputs and outputs. The number of inputs is limited to 6.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *d) override
{
log_header(d, "Executing CELLMATCH pass. (match cells)\n");
size_t argidx;
bool lut_attrs = false;
Design *lib = NULL;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-lut_attrs") {
// an undocumented debugging option
lut_attrs = true;
} else if (args[argidx] == "-lib" && argidx + 1 < args.size()) {
if (!saved_designs.count(args[++argidx]))
log_cmd_error("No design '%s' found!\n", args[argidx].c_str());
lib = saved_designs.at(args[argidx]);
} else {
break;
}
}
extra_args(args, argidx, d);
if (!lib && !lut_attrs)
log_cmd_error("Missing required -lib option.\n");
struct Target {
Module *module;
std::vector<uint64_t> luts;
};
dict<pool<uint64_t>, std::vector<Target>> targets;
if (lib)
for (auto m : lib->modules()) {
pool<uint64_t> p_classes;
// produce a fingerprint in p_classes
int ninputs = module_inputs(m).size();
std::vector<uint64_t> luts;
if (!derive_module_luts(m, luts))
continue;
for (auto lut : luts)
p_classes.insert(p_class(ninputs, lut));
// save as a viable target
targets[p_classes].push_back(Target{m, luts});
}
auto r = saved_designs.emplace("$cellmatch_map", nullptr);
if (r.second)
r.first->second = new Design;
Design *map_design = r.first->second;
for (auto m : d->selected_whole_modules_warn()) {
std::vector<uint64_t> luts;
if (!derive_module_luts(m, luts))
continue;
SigSpec inputs = module_inputs(m);
SigSpec outputs = module_outputs(m);
if (lut_attrs) {
int no = 0;
for (auto bit : outputs) {
log_assert(bit.is_wire());
bit.wire->attributes[ID(p_class)] = p_class(inputs.size(), luts[no]);
bit.wire->attributes[ID(lut)] = luts[no++];
}
}
// fingerprint
pool<uint64_t> p_classes;
for (auto lut : luts)
p_classes.insert(p_class(inputs.size(), lut));
for (auto target : targets[p_classes]) {
log_debug("Candidate %s for matching to %s\n", log_id(target.module), log_id(m));
SigSpec target_inputs = module_inputs(target.module);
SigSpec target_outputs = module_outputs(target.module);
if (target_inputs.size() != inputs.size())
continue;
if (target_outputs.size() != outputs.size())
continue;
std::vector<int> input_map;
for (int i = 0; i < inputs.size(); i++)
input_map.push_back(i);
bool found_match = false;
while (!found_match) {
std::vector<int> output_map;
for (int i = 0; i < outputs.size(); i++)
output_map.push_back(i);
while (!found_match) {
int out_no = 0;
bool match = true;
for (auto lut : luts) {
if (permute_lut(target.luts[output_map[out_no++]], input_map) != lut) {
match = false;
break;
}
}
if (match) {
log("Module %s matches %s\n", log_id(m), log_id(target.module));
Module *map = map_design->addModule(stringf("\\_60_%s_%s", log_id(m), log_id(target.module)));
Cell *cell = map->addCell(ID::_TECHMAP_REPLACE_, target.module->name);
map->attributes[ID(techmap_celltype)] = m->name.str();
for (int i = 0; i < outputs.size(); i++) {
log_assert(outputs[i].is_wire());
Wire *w = map->addWire(outputs[i].wire->name, 1);
w->port_id = outputs[i].wire->port_id;
w->port_output = true;
log_assert(target_outputs[output_map[i]].is_wire());
cell->setPort(target_outputs[output_map[i]].wire->name, w);
}
for (int i = 0; i < inputs.size(); i++) {
log_assert(inputs[i].is_wire());
Wire *w = map->addWire(inputs[i].wire->name, 1);
w->port_id = inputs[i].wire->port_id;
w->port_input = true;
log_assert(target_inputs[input_map[i]].is_wire());
cell->setPort(target_inputs[input_map[i]].wire->name, w);
}
map->fixup_ports();
found_match = true;
}
if (!std::next_permutation(output_map.begin(), output_map.end()))
break;
}
if (!std::next_permutation(input_map.begin(), input_map.end()))
break;
}
}
}
}
} CellmatchPass;
YOSYS_NAMESPACE_END