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-rw-r--r--backends/smt2/Makefile.inc3
-rw-r--r--backends/smt2/smt2.cc350
2 files changed, 353 insertions, 0 deletions
diff --git a/backends/smt2/Makefile.inc b/backends/smt2/Makefile.inc
new file mode 100644
index 00000000..4e0a393a
--- /dev/null
+++ b/backends/smt2/Makefile.inc
@@ -0,0 +1,3 @@
+
+OBJS += backends/smt2/smt2.o
+
diff --git a/backends/smt2/smt2.cc b/backends/smt2/smt2.cc
new file mode 100644
index 00000000..d5cf856b
--- /dev/null
+++ b/backends/smt2/smt2.cc
@@ -0,0 +1,350 @@
+/*
+ * 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/rtlil.h"
+#include "kernel/register.h"
+#include "kernel/sigtools.h"
+#include "kernel/celltypes.h"
+#include "kernel/log.h"
+#include <string>
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+struct Smt2Worker
+{
+ CellTypes ct;
+ SigMap sigmap;
+ RTLIL::Module *module;
+
+ std::vector<std::string> decls, clauses, trans;
+ std::map<RTLIL::SigBit, std::string> bool_cache;
+ std::map<RTLIL::IdString, std::vector<RTLIL::Cell*>> cells_by_type;
+
+ Smt2Worker(RTLIL::Module *module) : ct(module->design), sigmap(module), module(module)
+ {
+ decls.push_back(stringf("(declare-sort |%s_s| 0)\n", log_id(module)));
+ }
+
+ std::string get_bool(RTLIL::SigBit bit, const char *state_name = "state")
+ {
+ sigmap.apply(bit);
+
+ if (bit.wire == nullptr)
+ return bit.data == RTLIL::State::S1 ? "true" : "false";
+
+ if (!bool_cache.count(bit)) {
+ std::string name = stringf("|%s_n %s %d|", log_id(module), log_id(bit.wire), bit.offset);
+ for (auto &c : name)
+ if (c == '\\') c = '/';
+ decls.push_back(stringf("(declare-fun %s (|%s_s|) Bool)\n", name.c_str(), log_id(module)));
+ bool_cache[bit] = name;
+ }
+
+ return stringf("(%s %s)", bool_cache.at(bit).c_str(), state_name);
+ }
+
+ void make_wire(RTLIL::Wire *wire)
+ {
+ for (int i = 0; i < GetSize(wire); i++)
+ get_bool(RTLIL::SigBit(wire, i));
+ }
+
+ void run_gates()
+ {
+ // basic gate-level logic cell types
+
+ for (auto cell : cells_by_type["$_BUF_"])
+ clauses.push_back(stringf(" (= %s %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_BUF_");
+
+ for (auto cell : cells_by_type["$_NOT_"])
+ clauses.push_back(stringf(" (distinct %s %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_NOT_");
+
+ for (auto cell : cells_by_type["$_AND_"])
+ clauses.push_back(stringf(" (= (and %s %s) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_AND_");
+
+ for (auto cell : cells_by_type["$_OR_"])
+ clauses.push_back(stringf(" (= (or %s %s) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_OR_");
+
+ for (auto cell : cells_by_type["$_XOR_"])
+ clauses.push_back(stringf(" (= (xor %s %s) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_XOR_");
+
+ for (auto cell : cells_by_type["$_MUX_"])
+ clauses.push_back(stringf(" (= (ite %s %s %s) %s)\n",
+ get_bool(cell->getPort("\\S").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_MUX_");
+
+
+ // inverted gate-level logic cell types
+
+ for (auto cell : cells_by_type["$_NAND_"])
+ clauses.push_back(stringf(" (distinct (and %s %s) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_NAND_");
+
+ for (auto cell : cells_by_type["$_NOR_"])
+ clauses.push_back(stringf(" (distinct (or %s %s) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_NOR_");
+
+ for (auto cell : cells_by_type["$_XNOR_"])
+ clauses.push_back(stringf(" (distinct (xor %s %s) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_XNOR_");
+
+
+ // advanced cmos-style logic cell types
+
+ for (auto cell : cells_by_type["$_AOI3_"])
+ clauses.push_back(stringf(" (distinct (or (and %s %s) %s) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\C").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_AOI3_");
+
+ for (auto cell : cells_by_type["$_AOI4_"])
+ clauses.push_back(stringf(" (distinct (or (and %s %s) (and %s %s)) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\C").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\D").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_AOI4_");
+
+ for (auto cell : cells_by_type["$_OAI3_"])
+ clauses.push_back(stringf(" (distinct (or (and %s %s) %s) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\C").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_OAI3_");
+
+ for (auto cell : cells_by_type["$_OAI4_"])
+ clauses.push_back(stringf(" (distinct (or (and %s %s) (and %s %s)) %s)\n",
+ get_bool(cell->getPort("\\A").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\B").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\C").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\D").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Y").to_single_sigbit()).c_str()));
+ cells_by_type.erase("$_OAI4_");
+
+
+ // simple DFF cells (ignoring clock domains)
+
+ for (auto cell : cells_by_type["$_DFF_P_"])
+ trans.push_back(stringf(" (= %s %s)\n",
+ get_bool(cell->getPort("\\D").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Q").to_single_sigbit(), "next_state").c_str()));
+ cells_by_type.erase("$_DFF_P_");
+
+ for (auto cell : cells_by_type["$_DFF_N_"])
+ trans.push_back(stringf(" (= %s %s)\n",
+ get_bool(cell->getPort("\\D").to_single_sigbit()).c_str(),
+ get_bool(cell->getPort("\\Q").to_single_sigbit(), "next_state").c_str()));
+ cells_by_type.erase("$_DFF_N_");
+ }
+
+ void run()
+ {
+ for (auto port : module->ports)
+ make_wire(module->wire(port));
+
+ for (auto cell : module->cells())
+ cells_by_type[cell->type].push_back(cell);
+
+ run_gates();
+
+ for (auto &it : cells_by_type)
+ log_error("Found %d cells of unsupported type %s in module %s.\n", GetSize(it.second), log_id(it.first), log_id(module));
+ }
+
+ void write(std::ostream &f)
+ {
+ for (auto it : decls)
+ f << it;
+ f << stringf("(define-fun |%s_c| ((state |%s_s|)) Bool (and\n", log_id(module), log_id(module));
+ for (auto it : clauses)
+ f << it;
+ f << "true true))\n";
+ f << stringf("(define-fun |%s_t| ((state |%s_s|)(next_state |%s_s|)) Bool (and\n", log_id(module), log_id(module), log_id(module));
+ for (auto it : trans)
+ f << it;
+ f << "true true))\n";
+ }
+};
+
+struct Smt2Backend : public Backend {
+ Smt2Backend() : Backend("smt2", "write design to SMT-LIBv2 file") { }
+ virtual void help()
+ {
+ // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+ log("\n");
+ log(" write_smt2 [options] [filename]\n");
+ log("\n");
+ log("Write a SMT-LIBv2 description of the current design. For a module with name\n");
+ log("'<mod>' this will declare the sort '<mod>_s' and the two functions '<mod>_c'\n");
+ log("(of arity 1) and '<mod>_t' (of arity 2).\n");
+ log("\n");
+ log("The sort represents the state of the module. Additional '<mod>_n' functions are\n");
+ log("declared that can be used to access the values of all signals in the module.\n");
+ log("\n");
+ log("The '<mod>_c' function evaluates to 'true' when the given state is consistent\n");
+ log("with the description of the models.\n");
+ log("\n");
+ log("The '<mod>_t' function evaluates to 'true' when the given pair of states is\n");
+ log("describes a valid state transition, provided that '<mod>_c' is true for both\n");
+ log("states.\n");
+ log("\n");
+ log(" -tpl <template_file>\n");
+ log(" use the given template file. the line containing only the token '%%%%'\n");
+ log(" is replaced with the regular output of this command.\n");
+ log("\n");
+ log("---------------------------------------------------------------------------\n");
+ log("\n");
+ log("Example:\n");
+ log("\n");
+ log("Consider the following module (test.v). We want to prove that the output can\n");
+ log("never transition from a non-zero value to a zero value.\n");
+ log("\n");
+ log(" module test(input clk, output reg [3:0] y);\n");
+ log(" always @(posedge clk)\n");
+ log(" y <= (y << 1) | ^y;\n");
+ log(" endmodule\n");
+ log("\n");
+ log("For this proof we create the following template (test.tpl).\n");
+ log("\n");
+ log(" ; we only need QF_UF for this poof\n");
+ log(" (set-logic QF_UF)\n");
+ log("\n");
+ log(" ; insert the auto-generated code here\n");
+ log(" %%%%\n");
+ log("\n");
+ log(" ; declare two state variables s1 and s2\n");
+ log(" (declare-fun s1 () test_s)\n");
+ log(" (declare-fun s2 () test_s)\n");
+ log("\n");
+ log(" ; both states are valid and s2 follows s1\n");
+ log(" (assert (test_c s1))\n");
+ log(" (assert (test_c s2))\n");
+ log(" (assert (test_t s1 s2))\n");
+ log("\n");
+ log(" ; we are looking for a solution with y non-zero in s1\n");
+ log(" (assert (or (|test_n y 0| s1) (|test_n y 1| s1)\n");
+ log(" (|test_n y 2| s1) (|test_n y 3| s1)))\n");
+ log("\n");
+ log(" ; we are looking for a solution with y zero in s2\n");
+ log(" (assert (not (or (|test_n y 0| s2) (|test_n y 1| s2)\n");
+ log(" (|test_n y 2| s2) (|test_n y 3| s2))))\n");
+ log("\n");
+ log(" ; is there such a solution?\n");
+ log(" (check-sat)\n");
+ log("\n");
+ log("The following yosys script will create a 'test.smt2' file for our proof:\n");
+ log("\n");
+ log(" read_verilog test.v\n");
+ log(" hierarchy; proc; techmap; opt -fast\n");
+ log(" write_smt2 -template test.tpl test.smt2\n");
+ log("\n");
+ log("Running 'cvc4 test.smt2' will print 'unsat' because y can never transition\n");
+ log("from non-zero to zero in the test design.\n");
+ log("\n");
+ }
+ virtual void execute(std::ostream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+ {
+ std::ifstream template_f;
+ log_header("Executing SMT2 backend.\n");
+
+ size_t argidx;
+ for (argidx = 1; argidx < args.size(); argidx++)
+ {
+ if (args[argidx] == "-template" && argidx+1 < args.size()) {
+ template_f.open(args[++argidx]);
+ if (template_f.fail())
+ log_error("Can't open template file `%s'.\n", args[argidx].c_str());
+ continue;
+ }
+ break;
+ }
+ extra_args(f, filename, args, argidx);
+
+ if (template_f.is_open()) {
+ std::string line;
+ while (std::getline(template_f, line)) {
+ int indent = 0;
+ while (indent < GetSize(line) && (line[indent] == ' ' || line[indent] == '\t'))
+ indent++;
+ if (line.substr(indent, 2) == "%%")
+ break;
+ *f << line << std::endl;
+ }
+ }
+
+ *f << stringf("; SMT-LIBv2 description generated by %s\n", yosys_version_str);
+
+ for (auto module : design->modules())
+ {
+ if (module->get_bool_attribute("\\blackbox") || module->has_memories_warn() || module->has_processes_warn())
+ continue;
+
+ log("Creating SMT-LIBv2 representation of module %s.\n", log_id(module));
+
+ Smt2Worker worker(module);
+ worker.run();
+ worker.write(*f);
+ }
+
+ *f << stringf("; end of yosys output\n");
+
+ if (template_f.is_open()) {
+ std::string line;
+ while (std::getline(template_f, line))
+ *f << line << std::endl;
+ }
+ }
+} Smt2Backend;
+
+PRIVATE_NAMESPACE_END
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-19 19:58:57 +0000