def block(self,
diag: Diagram,
j: int,
p: Phase,
trace: Optional[RelaxedTrace] = None,
safety_goal: bool = True) -> Union[Blocked, CexFound]:
if trace is None:
trace = []
if j == 0 or (j == 1 and self.valid_in_initial_frame(
self.solver, p, diag) is not None):
if safety_goal:
utils.logger.always_print('\n'.join(
((t.pp() + ' ') if t is not None else '') + str(diag)
for t, diag in trace))
print(
'abstract counterexample: the system has no universal inductive invariant proving safety'
)
# TODO: placeholder for analyzing relaxed trace
# import relaxed_traces
# print(relaxed_traces.diagram_trace_to_explicitly_relaxed_trace(trace, phases.phase_safety(p)))
if utils.args.checkpoint_out:
self.store_frames(utils.args.checkpoint_out)
raise AbstractCounterexample()
else:
if utils.logger.isEnabledFor(logging.DEBUG):
utils.logger.debug('failed to block diagram')
return CexFound()
while True:
with utils.LogTag(utils.logger, 'block-attempt'):
if utils.logger.isEnabledFor(logging.DEBUG):
utils.logger.debug('blocking diagram in frame %s' % j)
utils.logger.debug(str(diag))
self.print_frame(j - 1, lvl=logging.DEBUG)
res, x = self.find_predecessor(self[j - 1], p, diag)
if res == z3.unsat:
utils.logger.debug('no predecessor: blocked!')
assert x is None or isinstance(x, MySet)
core: Optional[MySet[int]] = x
self.augment_core_for_init(p, diag, core)
break
assert isinstance(x, tuple), (res, x)
trans, (pre_phase, pre_diag) = x
trace.append((trans, pre_diag))
ans = self.block(pre_diag, j - 1, pre_phase, trace,
safety_goal)
if not isinstance(ans, Blocked):
return ans
trace.pop()
if utils.logger.isEnabledFor(logging.DEBUG) and core is not None:
utils.logger.debug('core %s' % core)
utils.logger.debug('unminimized diag\n%s' % diag)
diag.minimize_from_core(core)
diag.generalize(self.solver, self[j - 1],
self.automaton.transitions_to_grouped_by_src(p),
p == self.automaton.init_phase(), j)
e = syntax.Not(diag.to_ast())
if utils.logger.isEnabledFor(logging.DEBUG):
utils.logger.debug(
'adding new clause to frames 0 through %d phase %s' %
(j, p.name()))
if utils.logger.isEnabledFor(logging.INFO):
utils.logger.info("[%d] %s" % (j, str(e)))
self.add(p, e, j)
utils.logger.debug("Done blocking")
return Blocked()
def block(self,
diag: Diagram,
j: int,
p: Phase,
trace: Optional[List[Tuple[Optional[PhaseTransition],
Union[Diagram, Expr]]]] = None,
safety_goal: bool = True) -> Union[Blocked, CexFound]:
if trace is None:
trace = []
if j == 0 or (j == 1 and self.valid_in_initial_frame(
self.solver, p, diag) is not None):
if safety_goal:
utils.logger.always_print('\n'.join(
((t.pp() + ' ') if t is not None else '') + str(diag)
for t, diag in trace))
print('abstract counterexample')
raise Exception('abstract counterexample')
else:
if utils.logger.isEnabledFor(logging.DEBUG):
utils.logger.debug('failed to block diagram')
# utils.logger.debug(str(diag))
return CexFound()
# print fs
while True:
with utils.LogTag(utils.logger, 'block-attempt'):
if utils.logger.isEnabledFor(logging.DEBUG):
utils.logger.debug('blocking diagram in frame %s' % j)
utils.logger.debug(str(diag))
self.print_frame(j - 1, lvl=logging.DEBUG)
res, x = self.find_predecessor(self[j - 1], p, diag)
if res == z3.unsat:
utils.logger.debug('no predecessor: blocked!')
assert x is None or isinstance(x, MySet)
core: Optional[MySet[int]] = x
self.augment_core_for_init(p, diag, core)
break
assert isinstance(x, tuple), (res, x)
trans, (pre_phase, pre_diag) = x
trace.append((trans, pre_diag))
ans = self.block(pre_diag, j - 1, pre_phase, trace,
safety_goal)
if not isinstance(ans, Blocked):
return ans
trace.pop()
if utils.logger.isEnabledFor(logging.DEBUG) and core is not None:
utils.logger.debug('core %s' % core)
utils.logger.debug('unminimized diag\n%s' % diag)
diag.minimize_from_core(core)
diag.generalize(self.solver, self[j - 1],
self.automaton.transitions_to_grouped_by_src(p),
p == self.automaton.init_phase(), j)
e = syntax.Not(diag.to_ast())
if utils.logger.isEnabledFor(logging.DEBUG):
utils.logger.debug(
'adding new clause to frames 0 through %d phase %s' %
(j, p.name()))
if utils.logger.isEnabledFor(logging.INFO):
utils.logger.info("[%d] %s" % (j, str(e)))
self.add(p, e, j)
utils.logger.debug("Done blocking")
return Blocked()