def guard_enabled(self, state, guard, verbose=0):
if guard.decl().name().startswith('table'):
conditional = self.tables[guard.decl().name()]
expression = z3p.BoolVal(False)
for condition, result in conditional:
expression = z3p.Or(expression, condition if z3p.is_true(result) else z3p.BoolVal(False))
guard = expression
guard_evaluated = util.evaluate_expression(guard, {}, state, self.tables)
if verbose > 0:
print 'Evaluated guard is {}'.format(guard_evaluated)
print 'Simplified guard is {}'.format(z3p.simplify(guard_evaluated))
s = z3p.Solver()
s.add(z3p.Neq(guard_evaluated, True))
if s.check() == z3p.unsat:
return True
else:
return False
def evaluate_expression(expression,
symbolic_memory,
concrete_memory,
tables=None):
if isinstance(expression, int):
return expression
if isinstance(expression, tuple):
return expression
if z3p.is_const(expression):
if z3p.is_bool_or_int_value(expression):
return expression
if expression in symbolic_memory:
return symbolic_memory[expression]
elif expression.decl().name().startswith('table_'):
assert expression.decl().name() in tables
table_expression = tables[expression.decl().name()]
first_value = table_expression[0][1]
if first_value.sort() == z3p.IntSort():
last_else = z3p.IntVal(0)
else:
last_else = z3p.BoolVal(False)
if_expression = None
for conditional, value in table_expression:
guard = evaluate_expression(conditional, symbolic_memory,
concrete_memory)
last_else = z3p.If(guard, value, last_else)
return z3p.simplify(last_else)
else:
return concrete_memory[expression]
elif expression.decl().kind() == z3p.Z3_OP_SELECT:
if expression in symbolic_memory:
return symbolic_memory[expression]
else:
return concrete_memory[expression]
else:
new_args = [
evaluate_expression(expression.arg(i), symbolic_memory,
concrete_memory, tables)
for i in range(expression.num_args())
]
if expression.decl().kind() == z3p.Z3_OP_AND:
return z3p.And(*new_args)
else:
return expression.decl()(*new_args)
def evaluate_expression(expression, symbolic_memory, concrete_memory, tables=None):
if isinstance(expression, int):
return expression
if isinstance(expression, tuple):
return expression
if z3p.is_const(expression):
if z3p.is_bool_or_int_value(expression):
return expression
if expression in symbolic_memory:
return symbolic_memory[expression]
elif expression.decl().name().startswith('table_'):
assert expression.decl().name() in tables
table_expression = tables[expression.decl().name()]
first_value = table_expression[0][1]
if first_value.sort() == z3p.IntSort():
last_else = z3p.IntVal(0)
else:
last_else = z3p.BoolVal(False)
if_expression = None
for conditional, value in table_expression:
guard = evaluate_expression(conditional, symbolic_memory, concrete_memory)
last_else = z3p.If(guard, value, last_else)
return z3p.simplify(last_else)
else:
return concrete_memory[expression]
elif expression.decl().kind() == z3p.Z3_OP_SELECT:
if expression in symbolic_memory:
return symbolic_memory[expression]
else:
return concrete_memory[expression]
else:
new_args = [evaluate_expression(expression.arg(i), symbolic_memory, concrete_memory, tables)
for i in range(expression.num_args())]
if expression.decl().kind() == z3p.Z3_OP_AND:
return z3p.And(*new_args)
else:
return expression.decl()(*new_args)
