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-rw-r--r--passes/sat/example.ys6
-rw-r--r--passes/sat/sat_solve.cc209
2 files changed, 178 insertions, 37 deletions
diff --git a/passes/sat/example.ys b/passes/sat/example.ys
index 19f8f50e..c532c1fb 100644
--- a/passes/sat/example.ys
+++ b/passes/sat/example.ys
@@ -1,11 +1,13 @@
+
read_verilog example.v
proc; opt_clean
+
sat_solve -set y 1'b1 example001
sat_solve -set y 1'b1 example002
sat_solve -set y_sshl 8'hf0 -set y_sshr 8'hf0 -set sh 4'd3 example003
sat_solve -set y 1'b1 example004
sat_solve -show rst,counter -set-at 3 y 1'b1 -seq 4 example004
-sat_solve -prove y 1'b0 example001
-# sat_solve -show rst,counter -prove y 1'b0 -set-at 1 rst 1'b1 -seq 1 example004
+sat_solve -prove y 1'b0 -show rst,counter,y example004
+sat_solve -prove y 1'b0 -show rst,counter,y -set-at 1 rst 1'b1 -seq 1 example004
diff --git a/passes/sat/sat_solve.cc b/passes/sat/sat_solve.cc
index bd8ffb6d..6a548ae5 100644
--- a/passes/sat/sat_solve.cc
+++ b/passes/sat/sat_solve.cc
@@ -17,6 +17,10 @@
*
*/
+// [[CITE]] Temporal Induction by Incremental SAT Solving
+// Niklas Een and Niklas Sörensson (2003)
+// http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.8161
+
#include "kernel/register.h"
#include "kernel/celltypes.h"
#include "kernel/sigtools.h"
@@ -124,7 +128,6 @@ struct SatHelper
std::vector<std::string> shows;
SigPool show_signal_pool;
SigSet<RTLIL::Cell*> show_drivers;
- std::map<RTLIL::Cell*,RTLIL::SigSpec> show_driven;
int max_timestep;
SatHelper(RTLIL::Design *design, RTLIL::Module *module) :
@@ -213,8 +216,6 @@ struct SatHelper
for (auto &p : c.second->connections)
if (ct.cell_output(c.second->type, p.first))
show_drivers.insert(sigmap(p.second), c.second);
- else
- show_driven[c.second].append(sigmap(p.second));
import_cell_counter++;
} else
log("Warning: failed to import cell %s (type %s) to SAT database.\n", RTLIL::id2cstr(c.first), RTLIL::id2cstr(c.second->type));
@@ -222,10 +223,9 @@ struct SatHelper
log("Imported %d cells to SAT database.\n", import_cell_counter);
}
- void setup_proof(int timestep = -1)
+ int setup_proof(int timestep = -1)
{
- if (prove.size() == 0)
- return;
+ assert(prove.size() > 0);
RTLIL::SigSpec big_lhs, big_rhs;
@@ -254,12 +254,24 @@ struct SatHelper
std::vector<int> lhs_vec = satgen.importSigSpec(big_lhs, timestep);
std::vector<int> rhs_vec = satgen.importSigSpec(big_rhs, timestep);
- ez.assume(ez.vec_ne(lhs_vec, rhs_vec));
+ return ez.vec_eq(lhs_vec, rhs_vec);
+ }
+
+ void force_unique_state(int timestep_from, int timestep_to)
+ {
+ RTLIL::SigSpec state_signals = satgen.initial_state.export_all();
+ for (int i = timestep_from; i < timestep_to; i++)
+ ez.assume(ez.vec_ne(satgen.importSigSpec(state_signals, i), satgen.importSigSpec(state_signals, timestep_to)));
+ }
+
+ bool solve(const std::vector<int> &assumptions)
+ {
+ return ez.solve(modelExpressions, modelValues, assumptions);
}
- bool solve()
+ bool solve(int a = 0, int b = 0, int c = 0, int d = 0, int e = 0, int f = 0)
{
- return ez.solve(modelExpressions, modelValues);
+ return ez.solve(modelExpressions, modelValues, a, b, c, d, e, f);
}
struct ModelBlockInfo {
@@ -285,28 +297,41 @@ struct SatHelper
void generate_model()
{
RTLIL::SigSpec modelSig;
+ modelExpressions.clear();
+ modelInfo.clear();
- // Add "normal" show signals for every timestep
+ // Add "show" signals or alternatively the leaves on the input cone on all set and prove signals
- if (shows.size() == 0) {
- SigPool handled_signals, final_signals;
- for (auto &s : show_driven)
- s.second.sort_and_unify();
- while (show_signal_pool.size() > 0) {
- RTLIL::SigSpec sig = show_signal_pool.export_one();
- show_signal_pool.del(sig);
+ if (shows.size() == 0)
+ {
+ SigPool queued_signals, handled_signals, final_signals;
+ queued_signals = show_signal_pool;
+ while (queued_signals.size() > 0) {
+ RTLIL::SigSpec sig = queued_signals.export_one();
+ queued_signals.del(sig);
handled_signals.add(sig);
std::set<RTLIL::Cell*> drivers = show_drivers.find(sig);
if (drivers.size() == 0) {
final_signals.add(sig);
} else {
for (auto &d : drivers)
- for (auto &p : d->connections)
- show_signal_pool.add(handled_signals.remove(p.second));
+ for (auto &p : d->connections) {
+ if (d->type == "$dff" && p.first == "\\CLK")
+ continue;
+ if (d->type.substr(0, 6) == "$_DFF_" && p.first == "\\C")
+ continue;
+ queued_signals.add(handled_signals.remove(p.second));
+ }
}
}
modelSig = final_signals.export_all();
- } else {
+
+ // additionally add all set and prove signals directly
+ // (it improves user confidence if we write the constraints back ;-)
+ modelSig.append(show_signal_pool.export_all());
+ }
+ else
+ {
for (auto &s : shows) {
RTLIL::SigSpec sig;
if (!parse_sigstr(sig, module, s))
@@ -339,7 +364,7 @@ struct SatHelper
// Add zero step signals as collected by satgen
- modelSig = satgen.initial_signals.export_all();
+ modelSig = satgen.initial_state.export_all();
for (auto &c : modelSig.chunks)
if (c.wire != NULL) {
ModelBlockInfo info;
@@ -417,6 +442,33 @@ struct SatHelper
}
};
+static void print_proof_failed()
+{
+ log("\n");
+ log(" ______ ___ ___ _ _ _ _ \n");
+ log(" (_____ \\ / __) / __) (_) | | | |\n");
+ log(" _____) )___ ___ ___ _| |__ _| |__ _____ _| | _____ __| | |\n");
+ log(" | ____/ ___) _ \\ / _ (_ __) (_ __|____ | | || ___ |/ _ |_|\n");
+ log(" | | | | | |_| | |_| || | | | / ___ | | || ____( (_| |_ \n");
+ log(" |_| |_| \\___/ \\___/ |_| |_| \\_____|_|\\_)_____)\\____|_|\n");
+ log("\n");
+}
+
+static void print_qed()
+{
+ log("\n");
+ log(" /$$$$$$ /$$$$$$$$ /$$$$$$$ \n");
+ log(" /$$__ $$ | $$_____/ | $$__ $$ \n");
+ log(" | $$ \\ $$ | $$ | $$ \\ $$ \n");
+ log(" | $$ | $$ | $$$$$ | $$ | $$ \n");
+ log(" | $$ | $$ | $$__/ | $$ | $$ \n");
+ log(" | $$/$$ $$ | $$ | $$ | $$ \n");
+ log(" | $$$$$$/ /$$| $$$$$$$$ /$$| $$$$$$$//$$\n");
+ log(" \\____ $$$|__/|________/|__/|_______/|__/\n");
+ log(" \\__/ \n");
+ log("\n");
+}
+
struct SatSolvePass : public Pass {
SatSolvePass() : Pass("sat_solve", "solve a SAT problem in the circuit") { }
virtual void help()
@@ -461,6 +513,9 @@ struct SatSolvePass : public Pass {
log(" induction proof it is proven that the condition holds forever after\n");
log(" the number of time steps passed using -seq.\n");
log("\n");
+ log(" -maxsteps <N>\n");
+ log(" Set a maximum length for the induction.\n");
+ log("\n");
log(" -verify\n");
log(" Return an error and stop the synthesis script if the proof fails.\n");
log("\n");
@@ -471,7 +526,7 @@ struct SatSolvePass : public Pass {
std::map<int, std::vector<std::pair<std::string, std::string>>> sets_at;
std::map<int, std::vector<std::string>> unsets_at;
std::vector<std::string> shows;
- int loopcount = 0, seq_len = 0;
+ int loopcount = 0, seq_len = 0, maxsteps = 0;
bool verify = false;
log_header("Executing SAT_SOLVE pass (solving SAT problems in the circuit).\n");
@@ -490,6 +545,10 @@ struct SatSolvePass : public Pass {
loopcount = atoi(args[++argidx].c_str());
continue;
}
+ if (args[argidx] == "-maxsteps" && argidx+1 < args.size()) {
+ maxsteps = atoi(args[++argidx].c_str());
+ continue;
+ }
if (args[argidx] == "-set" && argidx+2 < args.size()) {
std::string lhs = args[++argidx].c_str();
std::string rhs = args[++argidx].c_str();
@@ -543,10 +602,94 @@ struct SatSolvePass : public Pass {
if (prove.size() > 0 && seq_len > 0)
{
- log_cmd_error("Temporal induction proofs are not implemented yet!\n");
+ if (loopcount > 0)
+ log_cmd_error("The options -max and -all are not supported for temporal induction proofs!\n");
+
+ SatHelper basecase(design, module);
+ SatHelper inductstep(design, module);
+
+ basecase.sets = sets;
+ basecase.prove = prove;
+ basecase.sets_at = sets_at;
+ basecase.unsets_at = unsets_at;
+ basecase.shows = shows;
+
+ for (int timestep = 1; timestep <= seq_len; timestep++)
+ basecase.setup(timestep);
+
+ inductstep.sets = sets;
+ inductstep.prove = prove;
+ inductstep.shows = shows;
+
+ inductstep.setup(1);
+ inductstep.ez.assume(inductstep.setup_proof(1));
+
+ for (int inductlen = 1; inductlen <= maxsteps || maxsteps == 0; inductlen++)
+ {
+ log("\n** Trying induction with length %d **\n", inductlen);
+
+ // phase 1: proving base case
+
+ basecase.setup(seq_len + inductlen);
+ int property = basecase.setup_proof(seq_len + inductlen);
+ basecase.generate_model();
+
+ if (inductlen > 1)
+ basecase.force_unique_state(seq_len + 1, seq_len + inductlen);
+
+ log("\n[base case] Solving problem with %d variables and %d clauses..\n",
+ basecase.ez.numCnfVariables(), basecase.ez.numCnfClauses());
+
+ if (basecase.solve(basecase.ez.NOT(property))) {
+ log("SAT temporal induction proof finished - model found for base case: FAIL!\n");
+ print_proof_failed();
+ basecase.print_model();
+ goto tip_failed;
+ }
+
+ log("Base case for induction length %d proven.\n", inductlen);
+ basecase.ez.assume(property);
+
+ // phase 2: proving induction step
+
+ inductstep.setup(inductlen + 1);
+ property = inductstep.setup_proof(inductlen + 1);
+ inductstep.generate_model();
+
+ if (inductlen > 1)
+ inductstep.force_unique_state(1, inductlen + 1);
+
+ log("\n[induction step] Solving problem with %d variables and %d clauses..\n",
+ inductstep.ez.numCnfVariables(), inductstep.ez.numCnfClauses());
+
+ if (!inductstep.solve(inductstep.ez.NOT(property))) {
+ log("Induction step proven: SUCCESS!\n");
+ print_qed();
+ goto tip_success;
+ }
+
+ log("Induction step failed. Incrementing induction length.\n");
+ inductstep.ez.assume(property);
+
+ inductstep.print_model();
+ }
+
+ log("\nReached maximum number of time steps -> proof failed.\n");
+ print_proof_failed();
+
+ tip_failed:
+ if (verify) {
+ log("\n");
+ log_error("Called with -verify and proof did fail!\n");
+ }
+
+ tip_success:;
}
else
{
+ if (loopcount > 0)
+ log_cmd_error("The options -maxsteps is only supported for temporal induction proofs!\n");
+
SatHelper sathelper(design, module);
sathelper.sets = sets;
sathelper.prove = prove;
@@ -556,7 +699,8 @@ struct SatSolvePass : public Pass {
if (seq_len == 0) {
sathelper.setup();
- sathelper.setup_proof();
+ if (sathelper.prove.size() > 0)
+ sathelper.ez.assume(sathelper.ez.NOT(sathelper.setup_proof()));
} else {
for (int timestep = 1; timestep <= seq_len; timestep++)
sathelper.setup(timestep);
@@ -568,7 +712,7 @@ struct SatSolvePass : public Pass {
sathelper.ez.printDIMACS(stdout, true);
#endif
-rerun_solver:
+ rerun_solver:
log("\nSolving problem with %d variables and %d clauses..\n",
sathelper.ez.numCnfVariables(), sathelper.ez.numCnfClauses());
@@ -578,14 +722,7 @@ rerun_solver:
log("SAT solving finished - model found:\n");
} else {
log("SAT proof finished - model found: FAIL!\n");
- log("\n");
- log(" ______ ___ ___ _ _ _ _ \n");
- log(" (_____ \\ / __) / __) (_) | | | |\n");
- log(" _____) )___ ___ ___ _| |__ _| |__ _____ _| | _____ __| | |\n");
- log(" | ____/ ___) _ \\ / _ (_ __) (_ __|____ | | || ___ |/ _ |_|\n");
- log(" | | | | | |_| | |_| || | | | / ___ | | || ____( (_| |_ \n");
- log(" |_| |_| \\___/ \\___/ |_| |_| \\_____|_|\\_)_____)\\____|_|\n");
- log("\n");
+ print_proof_failed();
}
sathelper.print_model();
@@ -603,10 +740,12 @@ rerun_solver:
}
else
{
- if (prove.size() == 0)
+ if (prove.size() == 0) {
log("SAT solving finished - no model found.\n");
- else
+ } else {
log("SAT proof finished - no model found: SUCCESS!\n");
+ print_qed();
+ }
}
}
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-25 14:14:52 +0000