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obs_clean debug and fencing

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This commit is contained in:
Alain Dargelas 2025-02-27 10:13:16 -08:00
parent ee67e3c901
commit 4089c1b358
1 changed files with 83 additions and 21 deletions
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104
passes/silimate/obs_clean.cc
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@ -106,16 +106,28 @@ void collectTransitiveFanin(RTLIL::SigSpec &sig, SigMap &sigmap, dict<RTLIL::Sig
// Only keep the cells and wires that are visited using the transitive fanin reached from output ports or keep signals
void observabilityClean(RTLIL::Module *module, SigMap &sigmap, dict<RTLIL::SigSpec, std::set<Cell *>> &sig2CellsInFanin,
dict<RTLIL::SigSpec, RTLIL::SigSpec> &lhsSig2RhsSig, bool unused_wires)
dict<RTLIL::SigSpec, RTLIL::SigSpec> &lhsSig2RhsSig, bool unused_wires, bool unused_assigns, bool debug)
{
if (module->get_bool_attribute(ID::keep))
return;
std::set<Cell *> visitedCells;
std::set<RTLIL::SigSpec> visitedSigSpec;
if (debug) {
log("Collecting cell transitive fanin\n");
log_flush();
}
// Collect observable logic (connected to one output)
// By cells
for (auto elt : sig2CellsInFanin) {
RTLIL::SigSpec po = elt.first;
if ((!po.size()) || (!po[0].is_wire())) {
// Can't perform the analysis correctly.
if (debug) {
log("Module contains some logic that prevents obs_clean analysis\n");
log_flush();
}
return;
}
RTLIL::Wire *w = po[0].wire;
if (w && (!w->port_output) && (!w->get_bool_attribute(ID::keep))) {
continue;
@ -129,8 +141,21 @@ void observabilityClean(RTLIL::Module *module, SigMap &sigmap, dict<RTLIL::SigSp
}
}
if (debug) {
log("Collecting assign transitive fanin\n");
log_flush();
}
// By assigns
for (auto elt : lhsSig2RhsSig) {
RTLIL::SigSpec po = elt.first;
if ((!po.size()) || (!po[0].is_wire())) {
// Can't perform the analysis correctly.
if (debug) {
log("Module contains some logic that prevents obs_clean analysis\n");
log_flush();
}
return;
}
RTLIL::Wire *w = po[0].wire;
if (w && (!w->port_output) && (!w->get_bool_attribute(ID::keep))) {
continue;
@ -144,30 +169,40 @@ void observabilityClean(RTLIL::Module *module, SigMap &sigmap, dict<RTLIL::SigSp
}
}
// Remove unused assign stmts
std::vector<RTLIL::SigSig> newConnections;
for (auto it = module->connections().begin(); it != module->connections().end(); ++it) {
RTLIL::SigSpec lhs = it->first;
if (visitedSigSpec.count(sigmap(lhs))) {
newConnections.push_back(*it);
} else {
for (int i = 0; i < lhs.size(); i++) {
SigSpec bit_sig = lhs.extract(i, 1);
if (visitedSigSpec.count(sigmap(bit_sig))) {
newConnections.push_back(*it);
break;
if (unused_assigns) {
// Remove unused assign stmts
if (debug) {
log("Removing unused assign\n");
log_flush();
}
std::vector<RTLIL::SigSig> newConnections;
for (auto it = module->connections().begin(); it != module->connections().end(); ++it) {
RTLIL::SigSpec lhs = it->first;
if (visitedSigSpec.count(sigmap(lhs))) {
newConnections.push_back(*it);
} else {
for (int i = 0; i < lhs.size(); i++) {
SigSpec bit_sig = lhs.extract(i, 1);
if (visitedSigSpec.count(sigmap(bit_sig))) {
newConnections.push_back(*it);
break;
}
}
}
}
}
module->connections_.clear();
for (auto conn : newConnections) {
module->connect(conn);
module->connections_.clear();
for (auto conn : newConnections) {
module->connect(conn);
}
}
if (unused_wires) {
// Remove unused wires
if (debug) {
log("Removing unused wires\n");
log_flush();
}
// TODO: This impacts equiv_opt ability to perform equivalence checking
pool<RTLIL::Wire *> wiresToRemove;
for (auto wire : module->wires()) {
@ -197,6 +232,10 @@ void observabilityClean(RTLIL::Module *module, SigMap &sigmap, dict<RTLIL::SigSp
}
// Remove unused cells
if (debug) {
log("Removing unused cells\n");
log_flush();
}
std::set<Cell *> cellsToRemove;
for (auto cell : module->cells()) {
if (visitedCells.count(cell)) {
@ -229,13 +268,25 @@ struct ObsClean : public ScriptPass {
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
bool unused_wires = false;
bool unused_assigns = false;
bool debug = false;
if (std::getenv("DEBUG_OBS_CLEAN")) {
debug = true;
}
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-wires") {
unused_wires = true;
continue;
}
if (args[argidx] == "-assigns") {
unused_assigns = true;
continue;
}
if (args[argidx] == "-debug") {
debug = true;
continue;
}
break;
}
extra_args(args, argidx, design);
@ -252,18 +303,29 @@ struct ObsClean : public ScriptPass {
continue;
if (module->has_memories_warn())
continue;
if (debug) {
log("Processing module: %s\n", module->name.c_str());
log_flush();
}
SigMap sigmap(module);
// Precompute cell output sigspec to cell map
if (debug) {
log("Collecting cell info\n");
log_flush();
}
dict<RTLIL::SigSpec, std::set<Cell *>> sig2CellsInFanin;
dict<RTLIL::SigSpec, std::set<Cell *>> sig2CellsInFanout;
sigCellDrivers(module, sigmap, sig2CellsInFanout, sig2CellsInFanin);
// Precompute lhs2rhs and rhs2lhs sigspec map
if (debug) {
log("Collecting assign info\n");
log_flush();
}
dict<RTLIL::SigSpec, RTLIL::SigSpec> lhsSig2RhsSig;
dict<RTLIL::SigSpec, std::set<RTLIL::SigSpec>> rhsSig2LhsSig;
lhs2rhs_rhs2lhs(module, sigmap, rhsSig2LhsSig, lhsSig2RhsSig);
// Actual cleanup
observabilityClean(module, sigmap, sig2CellsInFanin, lhsSig2RhsSig, unused_wires);
observabilityClean(module, sigmap, sig2CellsInFanin, lhsSig2RhsSig, unused_wires, unused_assigns, debug);
}
log("End obs_clean pass\n");
log_flush();