def ast_to_smt(self, node):
"""
:type node: Node
"""
def convert_children(number=None):
if number is not None and len(node.children) != number:
raise Exception(
"The number of children ({}) differed from {}".format(
len(node.children), number))
return [self.ast_to_smt(child) for child in node.children]
if node.name == "ite":
return smt.Ite(*convert_children(3))
elif node.name == "~":
return smt.Not(*convert_children(1))
elif node.name == "^":
return smt.Pow(*convert_children(2))
elif node.name == "&":
return smt.And(*convert_children())
elif node.name == "|":
return smt.Or(*convert_children())
elif node.name == "*":
return smt.Times(*convert_children())
elif node.name == "+":
return smt.Plus(*convert_children())
elif node.name == "-":
return smt.Minus(*convert_children(2))
elif node.name == "<=":
return smt.LE(*convert_children(2))
elif node.name == ">=":
return smt.GE(*convert_children(2))
elif node.name == "<":
return smt.LT(*convert_children(2))
elif node.name == ">":
return smt.GT(*convert_children(2))
elif node.name == "=":
return smt.Equals(*convert_children(2))
elif node.name == "const":
c_type, c_value = [child.name for child in node.children]
if c_type == "bool":
return smt.Bool(bool(c_value))
elif c_type == "real":
return smt.Real(float(c_value))
else:
raise Exception("Unknown constant type {}".format(c_type))
elif node.name == "var":
v_type, v_name = [child.name for child in node.children]
if v_type == "bool":
v_smt_type = smt.BOOL
elif v_type == "real":
v_smt_type = smt.REAL
else:
raise Exception("Unknown variable type {}".format(v_type))
return smt.Symbol(v_name, v_smt_type)
else:
raise RuntimeError("Unrecognized node type '{}'".format(node.name))
def power(self, a, power):
return smt.Pow(a, smt.Real(power))
def walk_pow(self, base, exponent):
return smt.Pow(self.walk_smt(base), self.walk_smt(exponent))
def __getExpressionTree(symbolicExpression):
# TODO LATER: take into account bitwise shift operations
args = []
castType = None
if len(symbolicExpression.args) > 0:
for symbolicArg in symbolicExpression.args:
arg, type = Solver.__getExpressionTree(symbolicArg)
args.append(arg)
if castType is None:
castType = type
else:
if castType.literal == 'Integer':
if type.literal == 'Real':
castType = type
# TODO LATER: consider other possible castings
if castType.literal == 'Real':
for i in range(len(args)):
args[i] = pysmt.ToReal(args[i])
if isinstance(symbolicExpression, sympy.Not):
if castType.literal == 'Integer':
return pysmt.Equals(args[0], pysmt.Int(0)), Type('Bool')
elif castType.literal == 'Real':
return pysmt.Equals(args[0], pysmt.Real(0)), Type('Bool')
elif castType.literal == 'Bool':
return pysmt.Not(args[0]), Type('Bool')
else: # castType.literal == 'BitVector'
return pysmt.BVNot(args[0]), Type('BitVector')
elif isinstance(symbolicExpression, sympy.Lt):
return pysmt.LT(args[0], args[1]), Type('Bool')
elif isinstance(symbolicExpression, sympy.Gt):
return pysmt.GT(args[0], args[1]), Type('Bool')
elif isinstance(symbolicExpression, sympy.Ge):
return pysmt.GE(args[0], args[1]), Type('Bool')
elif isinstance(symbolicExpression, sympy.Le):
return pysmt.LE(args[0], args[1]), Type('Bool')
elif isinstance(symbolicExpression, sympy.Eq):
return pysmt.Equals(args[0], args[1]), Type('Bool')
elif isinstance(symbolicExpression, sympy.Ne):
return pysmt.NotEquals(args[0], args[1]), Type('Bool')
elif isinstance(symbolicExpression, sympy.And):
if castType.literal == 'Bool':
return pysmt.And(args[0], args[1]), Type('Bool')
else: # type.literal == 'BitVector'
return pysmt.BVAnd(args[0], args[1]), castType
elif isinstance(symbolicExpression, sympy.Or):
if castType.literal == 'Bool':
return pysmt.Or(args[0], args[1]), Type('Bool')
else: # type.literal == 'BitVector'
return pysmt.BVOr(args[0], args[1]), castType
elif isinstance(symbolicExpression, sympy.Xor):
return pysmt.BVXor(args[0], args[1]), castType
elif isinstance(symbolicExpression, sympy.Add):
return pysmt.Plus(args), castType
elif isinstance(symbolicExpression, sympy.Mul):
return pysmt.Times(args), castType
elif isinstance(symbolicExpression, sympy.Pow):
return pysmt.Pow(args[0], args[1]), castType
# TODO LATER: deal with missing modulo operator from pysmt
else:
if isinstance(symbolicExpression, sympy.Symbol):
symbolType = Variable.symbolTypes[symbolicExpression.name]
literal = symbolType.getTypeForSolver()
designator = symbolType.designatorExpr1
type = Type(literal, designator)
return Solver.__encodeTerminal(symbolicExpression, type), type
elif isinstance(symbolicExpression, sympy.Integer):
type = Type('Integer')
return Solver.__encodeTerminal(symbolicExpression, type), type
elif isinstance(symbolicExpression, sympy.Rational):
type = Type('Real')
return Solver.__encodeTerminal(symbolicExpression, type), type
elif isinstance(symbolicExpression, sympy.Float):
type = Type('Real')
return Solver.__encodeTerminal(symbolicExpression, type), type
else:
type = Type('Real')
return Solver.__encodeTerminal(symbolicExpression, type), type