def check_bmc(s: Solver, safety: Expr, depth: int, preconds: Optional[Iterable[Expr]] = None,
minimize: Optional[bool] = None) -> Optional[Trace]:
prog = syntax.the_program
if preconds is None:
preconds = (init.expr for init in prog.inits())
t = s.get_translator(depth + 1)
with s.new_frame():
for precond in preconds:
s.add(t.translate_expr(precond))
s.add(t.translate_expr(syntax.New(syntax.Not(safety), depth)))
for i in range(depth):
s.add(t.translate_expr(New(safety, i)))
assert_any_transition(s, t, i, allow_stutter=False)
res = s.check()
if res == solver.sat:
z3m = s.model(minimize=minimize)
m = Z3Translator.model_to_trace(z3m, depth + 1)
return m
elif res == solver.unknown:
print('unknown!')
return None
def check_solver(s: Solver, num_states: int, minimize: Optional[bool] = None) -> Optional[Trace]:
res = s.check()
m = None
if res != solver.unsat:
if res != solver.sat:
assert res == solver.unknown
utils.logger.always_print('unknown!')
utils.logger.always_print('reason unknown: ' + s.reason_unknown())
assert False, 'unexpected unknown from z3!'
assert res == solver.sat
m = Z3Translator.model_to_trace(s.model(minimize=minimize), num_states)
return m
def check_implication(
s: Solver,
hyps: Iterable[Expr],
concs: Iterable[Expr],
minimize: Optional[bool] = None) -> Optional[z3.ModelRef]:
t = s.get_translator(1)
with s.new_frame():
for e in hyps:
s.add(t.translate_expr(e))
for e in concs:
with s.new_frame():
s.add(t.translate_expr(Not(e)))
if s.check() != solver.unsat:
return s.model(minimize=minimize)
return None
def check_two_state_implication_all_transitions(
s: Solver,
old_hyps: Iterable[Expr],
new_conc: Expr,
minimize: Optional[bool] = None,
) -> Optional[Tuple[z3.ModelRef, DefinitionDecl]]:
t = s.get_translator(2)
prog = syntax.the_program
with s.new_frame():
for h in old_hyps:
s.add(t.translate_expr(h))
s.add(t.translate_expr(New(Not(new_conc))))
for trans in prog.transitions():
with s.new_frame():
s.add(t.translate_expr(trans.as_twostate_formula(prog.scope)))
res = s.check()
assert res in (solver.sat, solver.unsat), res
if res != solver.unsat:
return s.model(minimize=minimize), trans
return None