Improve smt2 encodings of assert/assume/cover, better wire_smt2 help msg
authorClifford Wolf <clifford@clifford.at>
Sat, 4 Mar 2017 22:41:54 +0000 (23:41 +0100)
committerClifford Wolf <clifford@clifford.at>
Sat, 4 Mar 2017 22:41:54 +0000 (23:41 +0100)
backends/smt2/smt2.cc
backends/smt2/smtio.py

index b550a40bd159eab8e38f46a6cfe049b536d7582f..9d07a1216e040dadefc291d903a2589c6e9e44af 100644 (file)
@@ -735,26 +735,41 @@ struct Smt2Worker
 
                if (verbose) log("=> export logic driving asserts\n");
 
+               int assert_id = 0, assume_id = 0, cover_id = 0;
                vector<string> assert_list, assume_list, cover_list;
+
                for (auto cell : module->cells())
-                       if (cell->type.in("$assert", "$assume", "$cover")) {
+               {
+                       if (cell->type.in("$assert", "$assume", "$cover"))
+                       {
+                               int &id = cell->type == "$assert" ? assert_id :
+                                               cell->type == "$assume" ? assume_id :
+                                               cell->type == "$cover" ? cover_id : *(int*)nullptr;
+
+                               char postfix = cell->type == "$assert" ? 'a' :
+                                               cell->type == "$assume" ? 'u' :
+                                               cell->type == "$cover" ? 'c' : 0;
+
                                string name_a = get_bool(cell->getPort("\\A"));
                                string name_en = get_bool(cell->getPort("\\EN"));
-                               decls.push_back(stringf("; yosys-smt2-%s %s#%d %s\n", cell->type.c_str() + 1, get_id(module), idcounter,
+                               decls.push_back(stringf("; yosys-smt2-%s %d %s\n", cell->type.c_str() + 1, id,
                                                cell->attributes.count("\\src") ? cell->attributes.at("\\src").decode_string().c_str() : get_id(cell)));
+
                                if (cell->type == "$cover")
-                                       decls.push_back(stringf("(define-fun |%s#%d| ((state |%s_s|)) Bool (and %s %s)) ; %s\n",
-                                                       get_id(module), idcounter, get_id(module), name_a.c_str(), name_en.c_str(), get_id(cell)));
+                                       decls.push_back(stringf("(define-fun |%s_%c %d| ((state |%s_s|)) Bool (and %s %s)) ; %s\n",
+                                                       get_id(module), postfix, id, get_id(module), name_a.c_str(), name_en.c_str(), get_id(cell)));
                                else
-                                       decls.push_back(stringf("(define-fun |%s#%d| ((state |%s_s|)) Bool (or %s (not %s))) ; %s\n",
-                                                       get_id(module), idcounter, get_id(module), name_a.c_str(), name_en.c_str(), get_id(cell)));
+                                       decls.push_back(stringf("(define-fun |%s_%c %d| ((state |%s_s|)) Bool (or %s (not %s))) ; %s\n",
+                                                       get_id(module), postfix, id, get_id(module), name_a.c_str(), name_en.c_str(), get_id(cell)));
+
                                if (cell->type == "$assert")
-                                       assert_list.push_back(stringf("(|%s#%d| state)", get_id(module), idcounter++));
+                                       assert_list.push_back(stringf("(|%s_a %d| state)", get_id(module), id));
                                else if (cell->type == "$assume")
-                                       assume_list.push_back(stringf("(|%s#%d| state)", get_id(module), idcounter++));
-                               else if (cell->type == "$cover")
-                                       cover_list.push_back(stringf("(|%s#%d| state)", get_id(module), idcounter++));
+                                       assume_list.push_back(stringf("(|%s_u %d| state)", get_id(module), id));
+
+                               id++;
                        }
+               }
 
                for (int iter = 1; !registers.empty(); iter++)
                {
@@ -1036,33 +1051,72 @@ struct Smt2Backend : public Backend {
                log("    write_smt2 [options] [filename]\n");
                log("\n");
                log("Write a SMT-LIBv2 [1] description of the current design. For a module with name\n");
-               log("'<mod>' this will declare the sort '<mod>_s' (state of the module) and the\n");
-               log("functions operating on that state.\n");
+               log("'<mod>' this will declare the sort '<mod>_s' (state of the module) and will\n");
+               log("define and declare functions operating on that state.\n");
+               log("\n");
+               log("The following SMT2 functions are generated for a module with name '<mod>'.\n");
+               log("Some declarations/definitions are printed with a special comment. A prover\n");
+               log("using the SMT2 files can use those comments to collect all relevant metadata\n");
+               log("about the design.\n");
+               log("\n");
+               log("    ; yosys-smt2-module <mod>\n");
+               log("    (declare-sort |<mod>_s| 0)\n");
+               log("        The sort representing a state of module <mod>.\n");
+               log("\n");
+               log("    (define-fun |<mod>_h| ((state |<mod>_s|)) Bool (...))\n");
+               log("        This function must be asserted for each state to establish the\n");
+               log("        design hierarchy.\n");
+               log("\n");
+               log("    ; yosys-smt2-input <wirename> <width>\n");
+               log("    ; yosys-smt2-output <wirename> <width>\n");
+               log("    ; yosys-smt2-register <wirename> <width>\n");
+               log("    ; yosys-smt2-wire <wirename> <width>\n");
+               log("    (define-fun |<mod>_n <wirename>| (|<mod>_s|) (_ BitVec <width>))\n");
+               log("    (define-fun |<mod>_n <wirename>| (|<mod>_s|) Bool)\n");
+               log("        For each port, register, and wire with the 'keep' attribute set an\n");
+               log("        accessor function is generated. Single-bit wires are returned as Bool,\n");
+               log("        multi-bit wires as BitVec.\n");
+               log("\n");
+               log("    ; yosys-smt2-cell <submod> <instancename>\n");
+               log("    (declare-fun |<mod>_h <instancename>| (|<mod>_s|) |<submod>_s|)\n");
+               log("        There is a function like that for each hierarchical instance. It\n");
+               log("        returns the sort that represents the state of the sub-module that\n");
+               log("        implements the instance.\n");
+               log("\n");
+               log("    (declare-fun |<mod>_is| (|<mod>_s|) Bool)\n");
+               log("        This function must be asserted 'true' for initial states, and 'false'\n");
+               log("        otherwise.\n");
+               log("\n");
+               log("    (define-fun |<mod>_i| ((state |<mod>_s|)) Bool (...))\n");
+               log("        This function must be asserted 'true' for initial states. For\n");
+               log("        non-initial states it must be left unconstrained.\n");
+               log("\n");
+               log("    (define-fun |<mod>_t| ((state |<mod>_s|) (next_state |<mod>_s|)) Bool (...))\n");
+               log("        This function evaluates to 'true' if the states 'state' and\n");
+               log("        'next_state' form a valid state transition.\n");
                log("\n");
-               log("The '<mod>_s' sort represents a module state. Additional '<mod>_n' functions\n");
-               log("are provided that can be used to access the values of the signals in the module.\n");
-               log("By default only ports, registers, and wires with the 'keep' attribute set are\n");
-               log("made available via such functions. With the -nobv option, multi-bit wires are\n");
-               log("exported as separate functions of type Bool for the individual bits. Without\n");
-               log("-nobv multi-bit wires are exported as single functions of type BitVec.\n");
+               log("    (define-fun |<mod>_a| ((state |<mod>_s|)) Bool (...))\n");
+               log("        This function evaluates to 'true' if all assertions hold in the state.\n");
                log("\n");
-               log("The '<mod>_t' function evaluates to 'true' when the given pair of states\n");
-               log("describes a valid state transition.\n");
+               log("    (define-fun |<mod>_u| ((state |<mod>_s|)) Bool (...))\n");
+               log("        This function evaluates to 'true' if all assumptions hold in the state.\n");
                log("\n");
-               log("The '<mod>_a' function evaluates to 'true' when the given state satisfies\n");
-               log("the asserts in the module.\n");
+               log("    ; yosys-smt2-assert <id> <filename:linenum>\n");
+               log("    (define-fun |<mod>_a <id>| ((state |<mod>_s|)) Bool (...))\n");
+               log("        Each $assert cell is converted into one of this functions. The function\n");
+               log("        evaluates to 'true' if the assert statement holds in the state.\n");
                log("\n");
-               log("The '<mod>_u' function evaluates to 'true' when the given state satisfies\n");
-               log("the assumptions in the module.\n");
+               log("    ; yosys-smt2-assume <id> <filename:linenum>\n");
+               log("    (define-fun |<mod>_u <id>| ((state |<mod>_s|)) Bool (...))\n");
+               log("        Each $assume cell is converted into one of this functions. The function\n");
+               log("        evaluates to 'true' if the assume statement holds in the state.\n");
                log("\n");
-               log("The '<mod>_i' function evaluates to 'true' when the given state conforms\n");
-               log("to the initial state. Furthermore the '<mod>_is' function should be asserted\n");
-               log("to be true for initial states in addition to '<mod>_i', and should be\n");
-               log("asserted to be false for non-initial states.\n");
+               log("    ; yosys-smt2-cover <id> <filename:linenum>\n");
+               log("    (define-fun |<mod>_c <id>| ((state |<mod>_s|)) Bool (...))\n");
+               log("        Each $cover cell is converted into one of this functions. The function\n");
+               log("        evaluates to 'true' if the cover statement is activated in the state.\n");
                log("\n");
-               log("For hierarchical designs, the '<mod>_h' function must be asserted for each\n");
-               log("state to establish the design hierarchy. The '<mod>_h <cellname>' function\n");
-               log("evaluates to the state corresponding to the given cell within <mod>.\n");
+               log("Options:\n");
                log("\n");
                log("    -verbose\n");
                log("        this will print the recursive walk used to export the modules.\n");
index 1278d00aa7c4182848814fcab3404e83e457a3ad..38e3f31197614e294f2e52fb62af097e116536b4 100644 (file)
@@ -334,10 +334,10 @@ class SmtIo:
             self.modinfo[self.curmod].wsize[fields[2]] = int(fields[3])
 
         if fields[1] == "yosys-smt2-assert":
-            self.modinfo[self.curmod].asserts[fields[2]] = fields[3]
+            self.modinfo[self.curmod].asserts["%s_a %s" % (self.curmod, fields[2])] = fields[3]
 
         if fields[1] == "yosys-smt2-cover":
-            self.modinfo[self.curmod].covers[fields[2]] = fields[3]
+            self.modinfo[self.curmod].covers["%s_c %s" % (self.curmod, fields[2])] = fields[3]
 
         if fields[1] == "yosys-smt2-anyconst":
             self.modinfo[self.curmod].anyconsts[fields[2]] = fields[3]