Esempio n. 1
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    def generate_STS(self, var_str, init_str, invar_str, trans_str):
        ts = TS("Additional system")
        init = []
        trans = []
        invar = []

        sparser = StringParser()

        for var in var_str:
            ts.add_state_var(self._define_var(var))

        for init_s in init_str:
            init.append(sparser.parse_formula(init_s))

        for invar_s in invar_str:
            invar.append(sparser.parse_formula(invar_s))

        for trans_s in trans_str:
            trans.append(sparser.parse_formula(trans_s))

        ts.init = And(init)
        ts.invar = And(invar)
        ts.trans = And(trans)

        return ts
Esempio n. 2
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    def parse_string(self, contents:str)->HTS:
        '''
        Parses a string representation of an initial state file
        '''
        hts = HTS("INIT")
        ts = TS("TS INIT")

        init = []

        for line in contents.split('\n'):
            line = line.strip()
            if not line:
                continue
            else:
                res = self.parse_line(line)
                if res is not None:
                    init.append(res)

        Logger.msg("Initial state file set concrete values for {} state variables".format(len(init)), 1)

        ts.init = And(init)
        ts.invar = TRUE()
        ts.trans = TRUE()
        hts.add_ts(ts)

        return hts
Esempio n. 3
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    def parse_string(self, lines):

        [none, var, state, input, output, init, invar, trans,
         ftrans] = range(9)
        section = none

        inits = TRUE()
        invars = TRUE()
        transs = TRUE()
        ftranss = {}

        sparser = StringParser()

        count = 0
        vars = set([])
        states = set([])
        inputs = set([])
        outputs = set([])
        invar_props = []
        ltl_props = []

        for line in lines:
            count += 1

            if (line.strip() in ["", "\n"]) or line[0] == T_COM:
                continue

            if T_VAR == line[:len(T_VAR)]:
                section = var
                continue

            if T_STATE == line[:len(T_STATE)]:
                section = state
                continue

            if T_INPUT == line[:len(T_INPUT)]:
                section = input
                continue

            if T_OUTPUT == line[:len(T_OUTPUT)]:
                section = output
                continue

            if T_INIT == line[:len(T_INIT)]:
                section = init
                continue

            if T_INVAR == line[:len(T_INVAR)]:
                section = invar
                continue

            if T_TRANS == line[:len(T_TRANS)]:
                section = trans
                continue

            if T_FTRANS == line[:len(T_FTRANS)]:
                section = ftrans
                continue

            if section in [var, state, input, output]:
                varname, vartype = line[:-2].replace(" ", "").split(":")
                if varname[0] == "'":
                    varname = varname[1:-1]
                vartype = parse_typestr(vartype)
                vardef = self._define_var(varname, vartype)

                vars.add(vardef)
                if section == state:
                    states.add(vardef)
                if section == input:
                    inputs.add(vardef)
                if section == output:
                    outputs.add(vardef)

            if section in [init, invar, trans]:
                line = line.replace(T_SC, "").strip()
                qline = quote_names(line, replace_ops=False)

            if section == init:
                inits = And(inits, sparser.parse_formula(qline))

            if section == invar:
                invars = And(invars, sparser.parse_formula(qline))

            if section == trans:
                transs = And(transs, sparser.parse_formula(qline))

            if section == ftrans:
                strvar = line[:line.find(":=")]
                var = sparser.parse_formula(
                    quote_names(strvar, replace_ops=False))
                cond_ass = line[line.find(":=") + 2:].strip()
                ftranss[var] = []

                for cond_as in cond_ass.split("{"):
                    if cond_as == "":
                        continue
                    cond = cond_as[:cond_as.find(",")]
                    ass = cond_as[cond_as.find(",") + 1:cond_as.find("}")]
                    ftranss[var].append((sparser.parse_formula(
                        quote_names(cond, replace_ops=False)),
                                         sparser.parse_formula(
                                             quote_names(ass,
                                                         replace_ops=False))))

        hts = HTS("STS")
        ts = TS()

        ts.vars = vars
        ts.state_vars = states
        ts.input_vars = inputs
        ts.output_vars = outputs
        ts.init = inits
        ts.invar = invars
        ts.trans = transs
        ts.ftrans = ftranss

        hts.add_ts(ts)

        return (hts, invar_props, ltl_props)
Esempio n. 4
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    def generate_HTS(self, module, modulesdic):
        hts = HTS(module.name)
        ts = TS("TS %s" % module.name)

        init = []
        trans = []
        invar = []
        params = []

        sparser = StringParser()

        (vars, states, inputs,
         outputs) = self._collect_sub_variables(module,
                                                modulesdic,
                                                path=[],
                                                varlist=[],
                                                statelist=[],
                                                inputlist=[],
                                                outputlist=[])

        for var in vars:
            ts.add_var(self._define_var(var, module.name))

        for var in states:
            ts.add_state_var(self._define_var(var, module.name))

        for var in inputs:
            ts.add_input_var(self._define_var(var, module.name))

        for var in outputs:
            ts.add_output_var(self._define_var(var, module.name))

        self._check_parameters(module, modulesdic, ts.vars)

        for par in module.pars:
            assert len(par) == 2, "Expecting a variable"
            hts.add_param(self._define_var((par[0], par[1]), module.name))

        for init_s in module.init:
            formula = sparser.parse_formula(quote_names(init_s, module.name),
                                            False)
            init.append(formula)

        for invar_s in module.invar:
            formula = sparser.parse_formula(quote_names(invar_s, module.name),
                                            False)
            invar.append(formula)

        for trans_s in module.trans:
            formula = sparser.parse_formula(quote_names(trans_s, module.name),
                                            False)
            trans.append(formula)

        for sub in module.subs:
            hts.add_sub(sub[0],
                        self.generate_HTS(modulesdic[sub[1]], modulesdic),
                        tuple([v[0] for v in sub[2]]))

        ts.init = And(init)
        ts.invar = And(invar)
        ts.trans = And(trans)

        hts.add_ts(ts)

        return hts
Esempio n. 5
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    def solve_problems(self, problems, config):
        encoder_config = self.problems2encoder_config(config, problems)

        self.sparser = StringParser(encoder_config)
        self.lparser = LTLParser()

        self.coi = ConeOfInfluence()

        invar_props = []
        ltl_props = []
        si = False

        if len(problems.symbolic_inits) == 0:
            problems.symbolic_inits.add(si)

        HTSM = 0
        HTS2 = 1
        HTSD = (HTSM, si)

        model_extension = config.model_extension if problems.model_extension is None else problems.model_extension
        assume_if_true = config.assume_if_true or problems.assume_if_true
        cache_files = config.cache_files or problems.cache_files
        clean_cache = config.clean_cache

        modifier = None
        if model_extension is not None:
            modifier = lambda hts: ModelExtension.extend(
                hts, ModelModifiersFactory.modifier_by_name(model_extension))

        # generate systems for each problem configuration
        systems = {}
        for si in problems.symbolic_inits:
            encoder_config.symbolic_init = si
            (systems[(HTSM, si)], invar_props, ltl_props) = self.parse_model(problems.relative_path, \
                                                                             problems.model_file, \
                                                                             encoder_config, \
                                                                             "System 1", \
                                                                             modifier, \
                                                                             cache_files=cache_files, \
                                                                             clean_cache=clean_cache)

        if problems.equivalence is not None:
            (systems[(HTS2, si)], _, _) = self.parse_model(problems.relative_path, \
                                                           problems.equivalence, \
                                                           encoder_config, \
                                                           "System 2", \
                                                           cache_files=cache_files, \
                                                           clean_cache=clean_cache)
        else:
            systems[(HTS2, si)] = None

        if config.safety or config.problems:
            for invar_prop in invar_props:
                inv_prob = problems.new_problem()
                inv_prob.verification = VerificationType.SAFETY
                inv_prob.name = invar_prop[0]
                inv_prob.description = invar_prop[1]
                inv_prob.formula = invar_prop[2]
                problems.add_problem(inv_prob)

        if config.ltl or config.problems:
            for ltl_prop in ltl_props:
                ltl_prob = problems.new_problem()
                ltl_prob.verification = VerificationType.LTL
                ltl_prob.name = ltl_prop[0]
                ltl_prob.description = ltl_prop[1]
                ltl_prob.formula = ltl_prop[2]
                problems.add_problem(ltl_prob)

        if HTSD in systems:
            problems._hts = systems[HTSD]

        for problem in problems.problems:
            problem.hts = systems[(HTSM, problem.symbolic_init)]

            if problems._hts is None:
                problems._hts = problem.hts
            problem.hts2 = systems[(HTS2, problem.symbolic_init)]
            if problems._hts2 is None:
                problems._hts2 = problem.hts2
            problem.vcd = problems.vcd or config.vcd or problem.vcd
            problem.abstract_clock = problems.abstract_clock or config.abstract_clock
            problem.add_clock = problems.add_clock or config.add_clock
            problem.coi = problems.coi or config.coi
            problem.run_coreir_passes = problems.run_coreir_passes
            problem.relative_path = problems.relative_path
            problem.cardinality = max(problems.cardinality, config.cardinality)

            if not problem.full_trace:
                problem.full_trace = problems.full_trace
            if not problem.trace_vars_change:
                problem.trace_vars_change = problems.trace_vars_change
            if not problem.trace_all_vars:
                problem.trace_all_vars = problems.trace_all_vars
            if not problem.clock_behaviors:
                clk_bhvs = [
                    p for p in
                    [problems.clock_behaviors, config.clock_behaviors]
                    if p is not None
                ]
                if len(clk_bhvs) > 0:
                    problem.clock_behaviors = ";".join(clk_bhvs)
            if not problem.generators:
                problem.generators = config.generators

            Logger.log(
                "Solving with abstract_clock=%s, add_clock=%s" %
                (problem.abstract_clock, problem.add_clock), 2)

            if problem.trace_prefix is not None:
                problem.trace_prefix = "".join(
                    [problem.relative_path, problem.trace_prefix])

            if config.time or problems.time:
                timer_solve = Logger.start_timer("Problem %s" % problem.name,
                                                 False)
            try:
                self.__solve_problem(problem, config)

                if problem.verification is None:
                    Logger.log("Unset verification", 2)
                    continue

                Logger.msg(" %s\n" % problem.status, 0, not (Logger.level(1)))

                if (assume_if_true) and \
                   (problem.status == VerificationStatus.TRUE) and \
                   (problem.assumptions == None) and \
                   (problem.verification == VerificationType.SAFETY):

                    ass_ts = TS("Previous assumption from property")
                    if TS.has_next(problem.formula):
                        ass_ts.trans = problem.formula
                    else:
                        ass_ts.invar = problem.formula
                    problem.hts.reset_formulae()

                    problem.hts.add_ts(ass_ts)

                if config.time or problems.time:
                    problem.time = Logger.get_timer(timer_solve, False)

            except KeyboardInterrupt as e:
                Logger.msg("\b\b Skipped!\n", 0)
Esempio n. 6
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    def combine_systems(hts,
                        hts2,
                        k,
                        symbolic_init,
                        eqprop=None,
                        inc=True,
                        non_deterministic=False):
        htseq = HTS("eq")

        hts1_varnames = [v.symbol_name() for v in hts.vars]
        hts2_varnames = [v.symbol_name() for v in hts2.vars]

        map1 = dict([(v, TS.get_prefix_name(v, S1)) for v in hts1_varnames]+\
                    [(TS.get_prime_name(v), TS.get_prefix_name(TS.get_prime_name(v), S1)) for v in hts1_varnames])
        map2 = dict([(v, TS.get_prefix_name(v, S2)) for v in hts2_varnames]+\
                    [(TS.get_prime_name(v), TS.get_prefix_name(TS.get_prime_name(v), S2)) for v in hts2_varnames])

        ts1_init = TRUE()
        ts2_init = TRUE()

        if not symbolic_init:
            ts1_init = substitute(hts.single_init(), map1)
            ts2_init = substitute(hts2.single_init(), map2)

        ts1 = TS()
        ts1.vars = set([TS.get_prefix(v, S1) for v in hts.vars])
        ts1.set_behavior(ts1_init,\
                         substitute(hts.single_trans(), map1),\
                         substitute(hts.single_invar(), map1))
        ts1.state_vars = set([TS.get_prefix(v, S1) for v in hts.state_vars])

        ts2 = TS()
        ts2.vars = set([TS.get_prefix(v, S2) for v in hts2.vars])
        ts2.set_behavior(ts2_init,\
                         substitute(hts2.single_trans(), map2),\
                         substitute(hts2.single_invar(), map2))
        ts2.state_vars = set([TS.get_prefix(v, S2) for v in hts2.state_vars])

        htseq.add_ts(ts1)
        htseq.add_ts(ts2)

        assumptions = []
        lemmas = []

        def sets_intersect(set1, set2):
            for el in set1:
                if not el in set2:
                    return False
            return True

        if hts.assumptions is not None:
            for assumption in hts.assumptions:
                assumptions.append(assumption)

        if hts.lemmas is not None:
            for lemma in hts.lemmas:
                lemmas.append(lemma)

        if hts2.assumptions is not None:
            for assumption in hts2.assumptions:
                assumptions.append(assumption)

        if hts2.lemmas is not None:
            for lemma in hts2.lemmas:
                lemmas.append(lemma)

        for assumption in assumptions:
            fv_assumption = get_free_variables(assumption)
            c_assumption = TRUE()

            if sets_intersect(fv_assumption, hts.vars):
                c_assumption = And(c_assumption, substitute(assumption, map1))
            if sets_intersect(fv_assumption, hts2.vars):
                c_assumption = And(c_assumption, substitute(assumption, map2))

            if c_assumption != TRUE():
                htseq.add_assumption(c_assumption)

        for lemma in lemmas:
            fv_lemma = get_free_variables(lemma)
            c_lemma = TRUE()

            if sets_intersect(fv_lemma, hts.vars):
                c_lemma = And(c_lemma, substitute(lemma, map1))
            if sets_intersect(fv_lemma, hts2.vars):
                c_lemma = And(c_lemma, substitute(lemma, map2))

            if c_lemma != TRUE():
                htseq.add_lemma(c_lemma)

        miter_out = Symbol(EQS, BOOL)

        inputs = hts.input_vars.intersection(hts2.input_vars)
        outputs = hts.output_vars.intersection(hts2.output_vars)

        htseq.input_vars = set([
            TS.get_prefix(v, S1) for v in hts.input_vars
        ]).union(set([TS.get_prefix(v, S2) for v in hts2.input_vars]))
        htseq.output_vars = set([
            TS.get_prefix(v, S1) for v in hts.output_vars
        ]).union(set([TS.get_prefix(v, S2) for v in hts2.output_vars]))

        if symbolic_init or (not non_deterministic):
            states = hts.state_vars.intersection(hts2.state_vars)
        else:
            states = []

        eqinputs = TRUE()
        eqoutputs = TRUE()
        eqstates = TRUE()

        for inp in inputs:
            eqinputs = And(
                eqinputs,
                EqualsOrIff(TS.get_prefix(inp, S1), TS.get_prefix(inp, S2)))

        for out in outputs:
            eqoutputs = And(
                eqoutputs,
                EqualsOrIff(TS.get_prefix(out, S1), TS.get_prefix(out, S2)))

        for svar in states:
            eqstates = And(
                eqstates,
                EqualsOrIff(TS.get_prefix(svar, S1), TS.get_prefix(svar, S2)))

        if eqprop is None:
            if symbolic_init or (not non_deterministic):
                invar = And(eqinputs,
                            Iff(miter_out, Implies(eqstates, eqoutputs)))
            else:
                invar = And(eqinputs, Iff(miter_out, eqoutputs))

            Logger.log('Inferring equivalence property: {}'.format(invar), 2)
        else:
            sparser = StringParser()
            eqprop = sparser.parse_formulae(eqprop)
            if len(eqprop) > 1:
                Logger.error("Expecting a single equivalence property")
            eqprop = eqprop[0][1]
            invar = Iff(miter_out, eqprop)
            Logger.log('Using provided equivalence property: {}'.format(invar),
                       2)

        tsmo = TS()
        tsmo.vars = set([miter_out])
        tsmo.invar = invar
        htseq.add_ts(tsmo)

        return (htseq, miter_out)
Esempio n. 7
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    def solve_problems(self, problems_config: ProblemsManager) -> None:

        general_config = problems_config.general_config
        model_extension = general_config.model_extension
        assume_if_true = general_config.assume_if_true

        self.sparser = StringParser(general_config)
        self.lparser = LTLParser()

        self.coi = ConeOfInfluence()

        modifier = None
        if general_config.model_extension is not None:
            modifier = lambda hts: ModelExtension.extend(
                hts,
                ModelModifiersFactory.modifier_by_name(general_config.
                                                       model_extension))

        # generate main system system
        hts, invar_props, ltl_props = self.parse_model(
            general_config.model_files, problems_config.relative_path,
            general_config, "System 1", modifier)

        # Generate second models if any are necessary
        for problem in problems_config.problems:
            if problem.verification == VerificationType.EQUIVALENCE:
                if problem.equal_to is None:
                    raise RuntimeError(
                        "No second model for equivalence "
                        "checking provided for problem {}".format(
                            problem.name))

                hts2, _, _ = self.parse_model(problem.equal_to,
                                              problems_config.relative_path,
                                              general_config, "System 2",
                                              modifier)
                problems_config.add_second_model(problem, hts2)

        # TODO : contain these types of passes in functions
        #        they should be registered as passes

        if general_config.init is not None:
            iparser = InitParser()
            init_hts, inv_a, ltl_a = iparser.parse_file(
                general_config.init, general_config)
            assert inv_a is None and ltl_a is None, "Not expecting assertions from init state file"

            # remove old inits
            for ts in hts.tss:
                ts.init = TRUE()

            hts.combine(init_hts)
            hts.single_init(rebuild=True)

        # set default bit-wise initial values (0 or 1)
        if general_config.default_initial_value is not None:
            def_init_val = int(general_config.default_initial_value)
            try:
                if int(def_init_val) not in {0, 1}:
                    raise RuntimeError
            except:
                raise RuntimeError(
                    "Expecting 0 or 1 for default_initial_value,"
                    "but received {}".format(def_init_val))
            def_init_ts = TS("Default initial values")
            new_init = []
            initialized_vars = get_free_variables(hts.single_init())
            state_vars = hts.state_vars
            num_def_init_vars = 0
            num_state_vars = len(state_vars)

            const_arr_supported = True

            if hts.logic == L_ABV:
                for p in problems_config.problems:
                    if p.solver_name not in CONST_ARRAYS_SUPPORT:
                        const_arr_supported = False
                        Logger.warning(
                            "Using default_initial_value with arrays, "
                            "but one of the selected solvers, "
                            "{} does not support constant arrays. "
                            "Any assumptions on initial array values will "
                            "have to be done manually".format(
                                problem.solver_name))
                        break

            for sv in state_vars - initialized_vars:
                if sv.get_type().is_bv_type():
                    width = sv.get_type().width
                    if int(def_init_val) == 1:
                        val = BV((2**width) - 1, width)
                    else:
                        val = BV(0, width)

                    num_def_init_vars += 1
                elif sv.get_type().is_array_type() and \
                     sv.get_type().elem_type.is_bv_type() and \
                     const_arr_supported:
                    svtype = sv.get_type()
                    width = svtype.elem_type.width
                    if int(def_init_val) == 1:
                        val = BV((2**width) - 1, width)
                    else:
                        val = BV(0, width)
                    # create a constant array with a default value
                    val = Array(svtype.index_type, val)
                else:
                    continue

                def_init_ts.add_state_var(sv)
                new_init.append(EqualsOrIff(sv, val))
            def_init_ts.set_behavior(simplify(And(new_init)), TRUE(), TRUE())
            hts.add_ts(def_init_ts)
            Logger.msg(
                "Set {}/{} state elements to zero "
                "in initial state\n".format(num_def_init_vars, num_state_vars),
                1)

        problems_config.hts = hts

        # TODO: Update this so that we can control whether embedded assertions are solved automatically
        if not general_config.skip_embedded:
            for invar_prop in invar_props:
                problems_config.add_problem(
                    verification=VerificationType.SAFETY,
                    name=invar_prop[0],
                    description=invar_prop[1],
                    properties=invar_prop[2])
                self.properties.append(invar_prop[2])
            for ltl_prop in ltl_props:
                problems_config.add_problem(verification=VerificationType.LTL,
                                            name=invar_prop[0],
                                            description=invar_prop[1],
                                            properties=invar_prop[2])
                self.properties.append(ltl_prop[2])

        Logger.log(
            "Solving with abstract_clock=%s, add_clock=%s" %
            (general_config.abstract_clock, general_config.add_clock), 2)

        # ensure the miter_out variable exists
        miter_out = None

        for problem in problems_config.problems:
            if problem.name is not None:
                Logger.log(
                    "\n*** Analyzing problem \"%s\" ***" % (problem.name), 1)
                Logger.msg("Solving \"%s\" " % problem.name, 0,
                           not (Logger.level(1)))

            # apply parametric behaviors (such as toggling the clock)
            # Note: This is supposed to be *before* creating the combined system for equivalence checking
            #       we want this assumption to be applied to both copies of the clock
            problem_hts = ParametricBehavior.apply_to_problem(
                problems_config.hts, problem, general_config, self.model_info)

            if problem.verification == VerificationType.EQUIVALENCE:
                hts2 = problems_config.get_second_model(problem)
                problem_hts, miter_out = Miter.combine_systems(
                    hts, hts2, problem.bmc_length,
                    general_config.symbolic_init, problem.properties, True)

            try:
                # convert the formulas to PySMT FNodes
                # lemmas, assumptions and precondition always use the regular parser
                lemmas, assumptions, precondition = self.convert_formulae(
                    [
                        problem.lemmas, problem.assumptions,
                        problem.precondition
                    ],
                    parser=self.sparser,
                    relative_path=problems_config.relative_path)

                if problem.verification != VerificationType.LTL:
                    parser = self.sparser
                else:
                    parser = self.lparser

                prop = None
                if problem.properties is not None:
                    prop = self.convert_formula(
                        problem.properties,
                        relative_path=problems_config.relative_path,
                        parser=parser)
                    assert len(prop) == 1, "Properties should already have been split into " \
                        "multiple problems but found {} properties here".format(len(prop))
                    prop = prop[0]
                    self.properties.append(prop)
                else:
                    if problem.verification == VerificationType.SIMULATION:
                        prop = TRUE()
                    elif (problem.verification
                          is not None) and (problem.verification !=
                                            VerificationType.EQUIVALENCE):
                        Logger.error(
                            "Property not provided for problem {}".format(
                                problem.name))

                if problem.verification == VerificationType.EQUIVALENCE:
                    assert miter_out is not None
                    # set property to be the miter output
                    # if user provided a different equivalence property, this has already
                    # been incorporated in the miter_out
                    prop = miter_out
                    # reset the miter output
                    miter_out = None

                if precondition:
                    assert len(precondition
                               ) == 1, "There should only be one precondition"
                    prop = Implies(precondition[0], prop)

                # TODO: keep assumptions separate from the hts
                # IMPORTANT: CLEAR ANY PREVIOUS ASSUMPTIONS AND LEMMAS
                #   This was previously done in __solve_problem and has been moved here
                #   during the frontend refactor in April 2019
                # this is necessary because the problem hts is just a reference to the
                #   overall (shared) HTS
                problem_hts.assumptions = None
                problem_hts.lemmas = None

                # Compute the Cone Of Influence
                # Returns a *new* hts (not pointing to the original one anymore)
                if problem.coi:
                    if Logger.level(2):
                        timer = Logger.start_timer("COI")
                    hts = self.coi.compute(hts, prop)
                    if Logger.level(2):
                        Logger.get_timer(timer)

                if general_config.time:
                    timer_solve = Logger.start_timer(
                        "Problem %s" % problem.name, False)

                status, trace, traces, region = self.__solve_problem(
                    problem_hts, prop, lemmas, assumptions, problem)

                # set status for this problem
                problems_config.set_problem_status(problem, status)

                # TODO: Determine whether we need both trace and traces
                assert trace is None or traces is None, "Expecting either a trace or a list of traces"
                if trace is not None:
                    problem_traces = self.__process_trace(
                        hts, trace, general_config, problem)
                    problems_config.set_problem_traces(problem, problem_traces)

                if traces is not None:
                    traces_to_add = []
                    for trace in traces:
                        problem_trace = self.__process_trace(
                            hts, trace, general_config, problem)
                        for pt in problem_trace:
                            traces_to_add.append(pt)
                    problems_config.set_problem_traces(problem, traces_to_add)

                if problem.verification == VerificationType.PARAMETRIC:
                    assert region is not None
                    problems_config.set_problem_region(problem, region)

                if status is not None:
                    Logger.msg(" %s\n" % status, 0, not (Logger.level(1)))

                if (assume_if_true) and \
                   (status == VerificationStatus.TRUE) and \
                   (problem.assumptions == None) and \
                   (problem.verification == VerificationType.SAFETY):

                    # TODO: relax the assumption on problem.assumptions
                    #       can still add it, just need to make it an implication

                    ass_ts = TS("Previous assumption from property")
                    if TS.has_next(prop):
                        ass_ts.trans = prop
                    else:
                        ass_ts.invar = prop
                    # add assumptions to main system
                    problem_hts.reset_formulae()
                    problem_hts.add_ts(ass_ts)

                if general_config.time:
                    problems_config.set_problem_time(
                        problem, Logger.get_timer(timer_solve, False))

            except KeyboardInterrupt as e:
                Logger.msg("\b\b Skipped!\n", 0)
Esempio n. 8
0
    def parse_file(self, strfile, config, flags=None):
        self.config = config
        self.__reset_structures()

        Logger.msg("Reading CoreIR system... ", 1)
        top_module = self.context.load_from_file(strfile)

        if config.run_passes:
            self.run_passes()

        Modules.abstract_clock = self.config.abstract_clock
        Modules.symbolic_init = self.config.symbolic_init

        top_def = top_module.definition
        interface = list(top_module.type.items())
        modules = {}
        sym_map = {}

        not_defined_mods = []

        hts = HTS(top_module.name)
        invar_props = []
        ltl_props = []

        Logger.msg("Starting encoding... ", 1)

        count = 0

        def extract_value(x, modname, inst_intr, inst_conf, inst_mod):
            if x in inst_intr:
                return self.BVVar(modname + x, inst_intr[x].size)

            if x in inst_conf:
                xval = inst_conf[x].value
                if type(xval) == bool:
                    xval = 1 if xval else 0
                else:
                    if type(xval) != int:
                        try:
                            if xval.is_x():
                                xval = None
                            else:
                                xval = xval.as_uint()
                        except:
                            try:
                                xval = xval.val
                            except:
                                xval = xval.unsigned_value
                return xval

            if inst_mod.generated:
                inst_args = inst_mod.generator_args
                if x in inst_args:
                    return inst_args[x].value

            return None

        if Logger.level(1):
            timer = Logger.start_timer("IntConvertion", False)
            en_tprinting = False

        if Logger.level(2):
            ttimer = Logger.start_timer("Convertion", False)

        if self.config.deterministic:
            td_instances = top_def.instances
            top_def_instances = [(inst.selectpath, inst.config, inst.module)
                                 for inst in td_instances]
            top_def_instances.sort()
        else:
            top_def_instances = list(top_def.instances)

        totalinst = len(top_def_instances)

        for inst in top_def_instances:
            if Logger.level(1):
                count += 1
                if count % 300 == 0:
                    dtime = Logger.get_timer(timer, False)
                    if dtime > 2:
                        en_tprinting = True
                    if en_tprinting:
                        Logger.inline(
                            "%s" % status_bar(
                                (float(count) / float(totalinst))), 1)
                        timer = Logger.start_timer("IntConvertion", False)

                    if Logger.level(2):
                        Logger.get_timer(timer, False)

            ts = None

            if self.config.deterministic:
                (inst_name, inst_conf, inst_mod) = inst
            else:
                inst_name = inst.selectpath
                inst_conf = inst.config
                inst_mod = inst.module

            inst_type = inst_mod.name
            inst_intr = dict(inst_mod.type.items())
            modname = (SEP.join(inst_name)) + SEP

            values_dic = {}

            for x in self.attrnames:
                values_dic[x] = extract_value(x, modname, inst_intr, inst_conf,
                                              inst_mod)

            def args(ports_list):
                return [values_dic[x] for x in ports_list]

            sym = self.__mod_to_sym(inst_type, args)
            if sym is not None:
                sym_map[sym[0].symbol_name()] = (sym[0], sym[1])
                continue

            ts = self.__mod_to_impl(inst_type, args)

            if ts is not None:

                if flags is not None:
                    if CoreIRModelFlags.NO_INIT in flags:
                        ts.init = TRUE()

                    if CoreIRModelFlags.FC_LEMMAS in flags:
                        for v in ts.vars:
                            v_name = v.symbol_name()
                            if (CR in v_name) or (RCR in v_name):
                                cons_v_name = v_name[:len(
                                    CR)] if CR in v_name else v_name[:len(RCR)]
                                cons_v = Symbol(cons_v_name, v.symbol_type())
                                lemma = EqualsOrIff(
                                    cons_v,
                                    BV(values_dic[self.VALUE],
                                       cons_v.symbol_type().width))
                                hts.add_lemma(lemma)

                        for v in ts.state_vars:
                            lemma = EqualsOrIff(
                                v,
                                BV(values_dic[self.INIT],
                                   v.symbol_type().width))
                            hts.add_lemma(lemma)

                hts.add_ts(ts)
            else:
                if inst_type not in not_defined_mods:
                    intface = ", ".join([
                        "%s" % (v) for v in values_dic
                        if values_dic[v] is not None
                    ])
                    Logger.error(
                        "Module type \"%s\" with interface \"%s\" is not defined"
                        % (inst_type, intface))
                    not_defined_mods.append(inst_type)

        Logger.clear_inline(1)

        if self.config.deterministic:
            interface.sort()

        for var in interface:
            varname = SELF + SEP + var[0]
            bvvar = self.BVVar(varname, var[1].size)
            if (var[1].is_input()):
                hts.add_input_var(bvvar)
            else:
                hts.add_output_var(bvvar)

            # Adding clock behavior
            if (self.CLK in var[0].lower()) and (var[1].is_input()):
                self.clock_list.add(bvvar)
                if self.config.abstract_clock:
                    self.abstract_clock_list.add(
                        (bvvar, (BV(0, var[1].size), BV(1, var[1].size))))

        varmap = dict([(s.symbol_name(), s) for s in hts.vars])

        def split_paths(path):
            ret = []
            for el in path:
                ret += el.split(CSEP)

            return ret

        def dict_select(dic, el):
            return dic[el] if el in dic else None

        eq_conns = []
        eq_vars = set([])

        if self.config.deterministic:
            td_connections = top_def.connections
            top_def_connections = [
                ((conn.first.selectpath, conn.second.selectpath)
                 if conn.first.selectpath < conn.second.selectpath else
                 (conn.second.selectpath, conn.first.selectpath), conn)
                for conn in td_connections
            ]
            top_def_connections.sort()
        else:
            top_def_connections = list(top_def.connections)

        for conn in top_def_connections:

            if self.config.deterministic:
                first_selectpath = split_paths(conn[0][0])
                second_selectpath = split_paths(conn[0][1])
            else:
                first_selectpath = split_paths(conn.first.selectpath)
                second_selectpath = split_paths(conn.second.selectpath)

            first = SEP.join(first_selectpath)
            second = SEP.join(second_selectpath)

            firstvar = None
            secondvar = None

            if is_number(first_selectpath[-1]):
                firstname = SEP.join(first_selectpath[:-1])
            else:
                firstname = SEP.join(first_selectpath)

            if is_number(second_selectpath[-1]):
                secondname = SEP.join(second_selectpath[:-1])
            else:
                secondname = SEP.join(second_selectpath)

            first = (dict_select(varmap, self.remap_or2an(firstname)), None)
            second = (dict_select(varmap, self.remap_or2an(secondname)), None)

            firstvar = first[0]
            secondvar = second[0]

            if (firstvar is None) and (self.remap_or2an(firstname) in sym_map):
                firstvar = sym_map[self.remap_or2an(firstname)][1]

            if (secondvar is None) and (self.remap_or2an(secondname)
                                        in sym_map):
                secondvar = sym_map[self.remap_or2an(secondname)][1]

            if (firstvar is None) and (secondvar is not None):
                Logger.error("Symbol \"%s\" is not defined" % firstname)
                first = (Symbol(self.remap_or2an(firstname),
                                secondvar.symbol_type()), None)
            else:
                if firstvar.is_constant():
                    sel = int(first_selectpath[-1]) if (is_number(
                        first_selectpath[-1])) else None
                    first = (firstvar, sel)
                else:
                    if (is_number(first_selectpath[-1])) and (
                            firstvar.symbol_type() !=
                            BOOL) and (firstvar.symbol_type().width > 1):
                        sel = int(first_selectpath[-1])
                        first = (firstvar, sel)

            if (firstvar is not None) and (secondvar is None):
                Logger.error("Symbol \"%s\" is not defined" % secondname)
                second = (Symbol(self.remap_or2an(secondname),
                                 firstvar.symbol_type()), None)
            else:
                if secondvar.is_constant():
                    sel = int(second_selectpath[-1]) if (is_number(
                        second_selectpath[-1])) else None
                    second = (secondvar, sel)
                else:
                    if (is_number(second_selectpath[-1])) and (
                            secondvar.symbol_type() !=
                            BOOL) and (secondvar.symbol_type().width > 1):
                        sel = int(second_selectpath[-1])
                        second = (secondvar, sel)

            assert ((firstvar is not None) and (secondvar is not None))

            eq_conns.append((first, second))

            if firstvar.is_symbol():
                eq_vars.add(firstvar)
            if secondvar.is_symbol():
                eq_vars.add(secondvar)

        conns_len = len(eq_conns)

        if self.pack_connections:
            eq_conns = self.__pack_connections(eq_conns)

        if len(eq_conns) < conns_len:
            Logger.log("Packed %d connections" % (conns_len - len(eq_conns)),
                       1)

        eq_formula = TRUE()

        for eq_conn in eq_conns:

            (fst, snd) = eq_conn

            if fst[1] is None:
                first = fst[0]
            else:
                if len(fst) > 2:
                    first = BVExtract(fst[0], fst[1], fst[2])
                else:
                    first = BVExtract(fst[0], fst[1], fst[1])

            if snd[1] is None:
                second = snd[0]
            else:
                if len(snd) > 2:
                    second = BVExtract(snd[0], snd[1], snd[2])
                else:
                    second = BVExtract(snd[0], snd[1], snd[1])

            if (first.get_type() != BOOL) and (second.get_type() == BOOL):
                second = Ite(second, BV(1, 1), BV(0, 1))

            if (first.get_type() == BOOL) and (second.get_type() != BOOL):
                first = Ite(first, BV(1, 1), BV(0, 1))

            eq_formula = And(eq_formula, EqualsOrIff(first, second))

            Logger.log(str(EqualsOrIff(first, second)), 3)

        ts = TS("Connections")
        ts.invar = eq_formula
        ts.vars = eq_vars

        hts.add_ts(ts)

        if self.enc_map is not None:
            del (self.enc_map)

        if Logger.level(2):
            Logger.get_timer(ttimer)

        return (hts, invar_props, ltl_props)
Esempio n. 9
0
    def parse_file(self, file_path, config, flags=None):
        # coreir needs a string representing the path
        strfile = str(file_path)

        self.config = config
        self.__reset_structures()

        Logger.msg("Reading CoreIR system... ", 1)
        top_module = self.context.load_from_file(strfile)

        if config.run_coreir_passes:
            self.run_passes()

        Modules.abstract_clock = self.config.abstract_clock
        Modules.symbolic_init = self.config.symbolic_init

        top_def = top_module.definition
        interface = list(top_module.type.items())
        modules = {}
        sym_map = {}

        not_defined_mods = []

        hts = HTS(top_module.name)
        invar_props = []
        ltl_props = []

        Logger.msg("Starting encoding... ", 1)

        count = 0

        def extract_value(x, modname, inst_intr, inst_conf, inst_mod):
            if x in inst_intr:
                return self.BVVar(modname + x, inst_intr[x].size)

            if x in inst_conf:
                xval = inst_conf[x].value
                if type(xval) == bool:
                    xval = 1 if xval else 0
                else:
                    if type(xval) != int:
                        try:
                            xval = xval.as_uint()
                        except:
                            xval = None
                return xval

            if inst_mod.generated:
                inst_args = inst_mod.generator_args
                if x in inst_args:
                    return inst_args[x].value

            return None

        if Logger.level(1):
            timer = Logger.start_timer("IntConvertion", False)
            en_tprinting = False

        if Logger.level(2):
            ttimer = Logger.start_timer("Convertion", False)

        td_instances = top_def.instances
        top_def_instances = [(inst.selectpath, inst.config, inst.module)
                             for inst in td_instances]
        # sorting keeps the behavior deterministic
        top_def_instances.sort()

        totalinst = len(top_def_instances)

        for inst in top_def_instances:
            if Logger.level(1):
                count += 1
                if count % 300 == 0:
                    dtime = Logger.get_timer(timer, False)
                    if dtime > 2:
                        en_tprinting = True
                    if en_tprinting:
                        Logger.inline(
                            "%s" % status_bar(
                                (float(count) / float(totalinst))), 1)
                        timer = Logger.start_timer("IntConvertion", False)

                    if Logger.level(2):
                        Logger.get_timer(timer, False)

            ts = None

            (inst_name, inst_conf, inst_mod) = inst
            inst_type = inst_mod.name
            inst_intr = dict(inst_mod.type.items())
            modname = (SEP.join(inst_name)) + SEP

            values_dic = {}

            for x in self.attrnames:
                values_dic[x] = extract_value(x, modname, inst_intr, inst_conf,
                                              inst_mod)

            def args(ports_list):
                return [values_dic[x] for x in ports_list]

            sym = self.__mod_to_sym(inst_type, args)
            if sym is not None:
                sym_map[sym[0].symbol_name()] = (sym[0], sym[1])
                continue

            ts = self.__mod_to_impl(inst_type, args)

            if ts is not None:

                if flags is not None:
                    if CoreIRModelFlags.NO_INIT in flags:
                        ts.init = TRUE()

                    if CoreIRModelFlags.FC_LEMMAS in flags:
                        for v in ts.vars:
                            v_name = v.symbol_name()
                            if (CR in v_name) or (RCR in v_name):
                                cons_v_name = v_name[:len(
                                    CR)] if CR in v_name else v_name[:len(RCR)]
                                cons_v = Symbol(cons_v_name, v.symbol_type())
                                lemma = EqualsOrIff(
                                    cons_v,
                                    BV(values_dic[self.VALUE],
                                       cons_v.symbol_type().width))
                                hts.add_lemma(lemma)

                        for v in ts.state_vars:
                            lemma = EqualsOrIff(
                                v,
                                BV(values_dic[self.INIT],
                                   v.symbol_type().width))
                            hts.add_lemma(lemma)

                hts.add_ts(ts)
            else:
                if inst_type not in not_defined_mods:
                    intface = ", ".join([
                        "%s" % (v) for v in values_dic
                        if values_dic[v] is not None
                    ])
                    Logger.error(
                        "Module type \"%s\" with interface \"%s\" is not defined"
                        % (inst_type, intface))
                    not_defined_mods.append(inst_type)

        Logger.clear_inline(1)

        # sorting keeps the behavior deterministic
        interface.sort()

        for var in interface:
            varname = SELF + SEP + var[0]
            bvvar = self.BVVar(varname, var[1].size)
            if (var[1].is_input()):
                hts.add_input_var(bvvar)
            else:
                hts.add_output_var(bvvar)

            if var[1].kind == NAMED and var[1].name == COREIR_CLK:
                self.clock_list.add(bvvar)
                if self.config.abstract_clock:
                    self.abstract_clock_list.add(
                        (bvvar, (BV(0, var[1].size), BV(1, var[1].size))))
                else:
                    # add state variable that stores the previous clock value
                    # This is IMPORTANT for model checking soundness, but
                    #    it isn't obvious that this is necessary
                    #
                    # imagine we have an explicit clock encoding (not abstract_clock), e.g.
                    #   next(state_var) = (!clk & next(clk)) ? <state_update> : <old value>
                    # and if we're trying to prove something using k-induction, there's a "loop free"
                    #   constraint that the state and output variables don't repeat (reach the same
                    #   state twice) in the trace
                    #   but on a negedge clock, there can be scenarios where no state or outputs
                    #   can be updated and we'll get a trivial unsat which will be interpreted as
                    #   a converged proof -- uh oh
                    #
                    # adding this state element just ensures that the loop free constraint won't
                    #   be violated trivially
                    # e.g. on a neg-edge clock, this new state element will have changed

                    # make it hidden (won't be printed)
                    # HIDDEN_VAR is a prefix that printers check for
                    trailing_clock_var = self.BVVar(
                        "{}{}__prev".format(HIDDEN_VAR, varname), var[1].size)

                    ts = TS()
                    ts.add_state_var(trailing_clock_var)
                    # the initial state for this trailing variable is unconstrained
                    ts.set_behavior(
                        TRUE(),
                        EqualsOrIff(TS.get_prime(trailing_clock_var), bvvar),
                        TRUE())

                    hts.add_ts(ts)

        varmap = dict([(s.symbol_name(), s) for s in hts.vars])

        def split_paths(path):
            ret = []
            for el in path:
                ret += el.split(CSEP)

            return ret

        def dict_select(dic, el):
            return dic[el] if el in dic else None

        eq_conns = []
        eq_vars = set([])

        td_connections = top_def.connections
        top_def_connections = [
            ((conn.first.selectpath, conn.second.selectpath)
             if conn.first.selectpath < conn.second.selectpath else
             (conn.second.selectpath, conn.first.selectpath), conn)
            for conn in td_connections
        ]
        # sorting keeps the behavior deterministic
        top_def_connections.sort()

        for conn in top_def_connections:

            first_selectpath = split_paths(conn[0][0])
            second_selectpath = split_paths(conn[0][1])

            first = SEP.join(first_selectpath)
            second = SEP.join(second_selectpath)

            firstvar = None
            secondvar = None

            if is_number(first_selectpath[-1]):
                firstname = SEP.join(first_selectpath[:-1])
            else:
                firstname = SEP.join(first_selectpath)

            if is_number(second_selectpath[-1]):
                secondname = SEP.join(second_selectpath[:-1])
            else:
                secondname = SEP.join(second_selectpath)

            first = (dict_select(varmap, self.remap_or2an(firstname)), None)
            second = (dict_select(varmap, self.remap_or2an(secondname)), None)

            firstvar = first[0]
            secondvar = second[0]

            if (firstvar is None) and (self.remap_or2an(firstname) in sym_map):
                firstvar = sym_map[self.remap_or2an(firstname)][1]

            if (secondvar is None) and (self.remap_or2an(secondname)
                                        in sym_map):
                secondvar = sym_map[self.remap_or2an(secondname)][1]

            if (firstvar is None) and (secondvar is not None):
                Logger.error("Symbol \"%s\" is not defined" % firstname)
                first = (Symbol(self.remap_or2an(firstname),
                                secondvar.symbol_type()), None)
            else:
                if firstvar.is_constant():
                    sel = int(first_selectpath[-1]) if (is_number(
                        first_selectpath[-1])) else None
                    first = (firstvar, sel)
                else:
                    if (is_number(first_selectpath[-1])) and (
                            firstvar.symbol_type() !=
                            BOOL) and (firstvar.symbol_type().width > 1):
                        sel = int(first_selectpath[-1])
                        first = (firstvar, sel)

            if (firstvar is not None) and (secondvar is None):
                Logger.error("Symbol \"%s\" is not defined" % secondname)
                second = (Symbol(self.remap_or2an(secondname),
                                 firstvar.symbol_type()), None)
            else:
                if secondvar.is_constant():
                    sel = int(second_selectpath[-1]) if (is_number(
                        second_selectpath[-1])) else None
                    second = (secondvar, sel)
                else:
                    if (is_number(second_selectpath[-1])) and (
                            secondvar.symbol_type() !=
                            BOOL) and (secondvar.symbol_type().width > 1):
                        sel = int(second_selectpath[-1])
                        second = (secondvar, sel)

            assert ((firstvar is not None) and (secondvar is not None))

            eq_conns.append((first, second))

            if firstvar.is_symbol():
                eq_vars.add(firstvar)
            if secondvar.is_symbol():
                eq_vars.add(secondvar)

        conns_len = len(eq_conns)

        if self.pack_connections:
            eq_conns = self.__pack_connections(eq_conns)

        if len(eq_conns) < conns_len:
            Logger.log("Packed %d connections" % (conns_len - len(eq_conns)),
                       1)

        eq_formula = TRUE()

        for eq_conn in eq_conns:

            (fst, snd) = eq_conn

            if fst[1] is None:
                first = fst[0]
            else:
                if len(fst) > 2:
                    first = BVExtract(fst[0], fst[1], fst[2])
                else:
                    first = BVExtract(fst[0], fst[1], fst[1])

            if snd[1] is None:
                second = snd[0]
            else:
                if len(snd) > 2:
                    second = BVExtract(snd[0], snd[1], snd[2])
                else:
                    second = BVExtract(snd[0], snd[1], snd[1])

            if (first.get_type() != BOOL) and (second.get_type() == BOOL):
                second = Ite(second, BV(1, 1), BV(0, 1))

            if (first.get_type() == BOOL) and (second.get_type() != BOOL):
                first = Ite(first, BV(1, 1), BV(0, 1))

            eq_formula = And(eq_formula, EqualsOrIff(first, second))

            Logger.log(str(EqualsOrIff(first, second)), 3)

        ts = TS("Connections")
        ts.invar = eq_formula
        ts.vars = eq_vars

        hts.add_ts(ts)

        if self.enc_map is not None:
            del (self.enc_map)

        if Logger.level(2):
            Logger.get_timer(ttimer)

        # check that clocks were detected if there's any state
        if hts.state_vars:
            assert self.clock_list, "Expecting clocks if there are state variables"

        return (hts, invar_props, ltl_props)
    def parse_string(self, lines):

        [none, var, state, input, output, init, invar, trans] = range(8)
        section = none

        inits = TRUE()
        invars = TRUE()
        transs = TRUE()

        sparser = StringParser()

        count = 0
        vars = set([])
        states = set([])
        inputs = set([])
        outputs = set([])
        invar_props = []
        ltl_props = []

        for line in lines:
            count += 1

            if line.strip() in ["", "\n"]:
                continue

            if T_VAR == line[:len(T_VAR)]:
                section = var
                continue

            if T_STATE == line[:len(T_STATE)]:
                section = state
                continue

            if T_INPUT == line[:len(T_INPUT)]:
                section = input
                continue

            if T_OUTPUT == line[:len(T_OUTPUT)]:
                section = output
                continue

            if T_INIT == line[:len(T_INIT)]:
                section = init
                continue

            if T_INVAR == line[:len(T_INVAR)]:
                section = invar
                continue

            if T_TRANS == line[:len(T_TRANS)]:
                section = trans
                continue

            if section in [var, state, input, output]:
                line = line[:-2].replace(" ", "").split(":")
                varname, vartype = line[0], (line[1][:-1].split("("))
                if varname[0] == "'":
                    varname = varname[1:-1]
                vardef = self._define_var(varname, vartype)

                vars.add(vardef)
                if section == state:
                    states.add(vardef)
                if section == input:
                    inputs.add(vardef)
                if section == output:
                    outputs.add(vardef)

            if section in [init, invar, trans]:
                qline = quote_names(line[:-2], replace_ops=False)

            if section == init:
                inits = And(inits, sparser.parse_formula(qline))

            if section == invar:
                invars = And(invars, sparser.parse_formula(qline))

            if section == trans:
                transs = And(transs, sparser.parse_formula(qline))

        hts = HTS("STS")
        ts = TS()

        ts.vars = vars
        ts.state_vars = states
        ts.input_vars = inputs
        ts.output_vars = outputs
        ts.init = inits
        ts.invar = invars
        ts.trans = transs

        hts.add_ts(ts)

        return (hts, invar_props, ltl_props)
Esempio n. 11
0
File: coi.py Progetto: yuex1994/CoSA
    def compute(self, hts, prop):
        Logger.log("Building COI", 1)

        self._build_var_deps(hts)

        coi_vars = set(self._free_variables(prop))

        if (len(coi_vars) < 1) or (self.var_deps == {}):
            return hts

        if hts.assumptions is not None:
            for assumption in hts.assumptions:
                for v in self._free_variables(assumption):
                    coi_vars.add(v)

        if hts.lemmas is not None:
            for lemma in hts.lemmas:
                for v in self._free_variables(lemma):
                    coi_vars.add(v)

        coits = TS("COI")

        coi_vars = list(coi_vars)
        i = 0
        visited = set([])
        while i < len(coi_vars):
            var = coi_vars[i]
            if (var in visited) or (var not in self.var_deps):
                i += 1
                continue

            coi_vars = coi_vars[:i + 1] + list(
                self.var_deps[var]) + coi_vars[i + 1:]

            visited.add(var)
            i += 1

        coi_vars = frozenset(coi_vars)

        trans = list(
            conjunctive_partition(hts.single_trans(include_ftrans=True)))
        invar = list(
            conjunctive_partition(hts.single_invar(include_ftrans=True)))
        init = list(conjunctive_partition(hts.single_init()))

        coits.trans = [
            f for f in trans
            if self._intersect(coi_vars, self._free_variables(f))
        ]
        coits.invar = [
            f for f in invar
            if self._intersect(coi_vars, self._free_variables(f))
        ]
        coits.init = [
            f for f in init
            if self._intersect(coi_vars, self._free_variables(f))
        ]

        Logger.log("COI statistics:", 1)
        Logger.log("  Vars:  %s -> %s" % (len(hts.vars), len(coi_vars)), 1)
        Logger.log("  Init:  %s -> %s" % (len(init), len(coits.init)), 1)
        Logger.log("  Invar: %s -> %s" % (len(invar), len(coits.invar)), 1)
        Logger.log("  Trans: %s -> %s" % (len(trans), len(coits.trans)), 1)

        coits.trans = And(coits.trans)
        coits.invar = And(coits.invar)
        coits.init = And(coits.init)

        coits.vars = set([])
        for bf in [init, invar, trans]:
            for f in bf:
                for v in self._free_variables(f):
                    coits.vars.add(v)

        coits.input_vars = set([v for v in coi_vars if v in hts.input_vars])
        coits.output_vars = set([v for v in coi_vars if v in hts.output_vars])
        coits.state_vars = set([v for v in coi_vars if v in hts.state_vars])

        new_hts = HTS("COI")
        new_hts.add_ts(coits)

        if self.save_model:
            printer = HTSPrintersFactory.printer_by_name("STS")
            with open("/tmp/coi_model.ssts", "w") as f:
                f.write(printer.print_hts(new_hts, []))

        return new_hts