def __init__(self, cfg):
super(AbstractTypesAnalysis, self).__init__()
self._cfg = cfg
self._numeric_rel = NumericRelation(self._cfg)
self._string_rel = StringRelation(self._cfg)
self._bool_rel = BoolRelation(self._cfg)
self._possible_type_relations = [self._numeric_rel,
self._string_rel,
self._bool_rel]
class AbstractTypesAnalysis(object):
def __init__(self, cfg):
super(AbstractTypesAnalysis, self).__init__()
self._cfg = cfg
self._numeric_rel = NumericRelation(self._cfg)
self._string_rel = StringRelation(self._cfg)
self._bool_rel = BoolRelation(self._cfg)
self._possible_type_relations = [self._numeric_rel,
self._string_rel,
self._bool_rel]
def lattice_bottom(self):
return AbstractType(formula=False)
def _operation_type_implies(self, concrete_transformation, ret_var, ret_type, operands_with_types):
return z3.Implies(z3.And(*(type_relation.has_type_of_formula(operand_expr, concrete_transformation.current_location())
for (operand_expr, type_relation) in operands_with_types)),
ret_type.has_type_of_formula(ret_var, concrete_transformation.next_location()))
def _type_propagated_formula(self, expression_propagated_from, current_var_name, concrete_transformation):
return z3.And(*[self._operation_type_implies(concrete_transformation, current_var_name, type_rel,
[(expression_propagated_from, type_rel)])
for type_rel in self._possible_type_relations])
def _type_preserved_for_variables(self, concrete_transformation, variables_names_unchanged):
all_types_preserved_formula = True
for var_name in variables_names_unchanged:
all_types_preserved_formula = z3.And(all_types_preserved_formula,
self._type_propagated_formula(var_name, var_name, concrete_transformation))
return all_types_preserved_formula
def _no_change(self, concrete_transformation, abstract_type):
return AbstractType(self._type_preserved_for_variables(concrete_transformation,
self._cfg.program_vars()))
def _assign(self, concrete_transformation, abstract_type):
assigned_to_var_name = concrete_transformation.current_location().instruction().gens[0]
expression_assigned = concrete_transformation.current_location().instruction().uses[0]
change_to_assigned = self._type_propagated_formula(expression_assigned, assigned_to_var_name, concrete_transformation)
all_vars_except_changed = self._cfg.program_vars()
all_vars_except_changed.remove(assigned_to_var_name)
formula = z3.And(self._type_preserved_for_variables(concrete_transformation, all_vars_except_changed),
change_to_assigned)
return AbstractType(formula)
def _function_call_typing(self, concrete_transformation, ret_var, function_name, operands):
all_string_implies_string = self._operation_type_implies(concrete_transformation,
ret_var, self._string_rel,
[(operand, self._string_rel) for operand in operands])
all_numeric_implies_numeric = self._operation_type_implies(concrete_transformation,
ret_var, self._numeric_rel,
[(operand, self._numeric_rel) for operand in operands])
all_boolean_implies_boolean = self._operation_type_implies(concrete_transformation,
ret_var, self._bool_rel,
[(operand, self._bool_rel) for operand in operands])
if function_name in ['**', '*', '//', '/', '%', '-', '<<', '>>']:
return all_numeric_implies_numeric
if function_name == '+':
return z3.Or(all_numeric_implies_numeric, all_string_implies_string)
if function_name in ['&', '|', '^']:
# TODO: not support implicit conversion to boolean
return all_boolean_implies_boolean
if function_name == 'not':
return all_boolean_implies_boolean
else:
assert False, "Unknown function call"
def _binary(self, concrete_transformation, abstract_type):
instruction = concrete_transformation.current_location().instruction()
op = instruction.op
(assigned_to_var,) = instruction.gens
(operand1, operand2) = instruction.uses
return AbstractType(self._function_call_typing(concrete_transformation, assigned_to_var, op, [operand1, operand2]))
def _call(self, concrete_transformation, abstract_type):
instruction = concrete_transformation.current_location().instruction()
args = instruction.uses[1:] # TODO: add kargs (see TAC)
ret_var = instruction.gens[0]
function_name = instruction.func
return AbstractType(self._function_call_typing(concrete_transformation, ret_var, function_name, args))
def transform(self, concrete_transformation, abstract_type):
instruction = concrete_transformation.current_location().instruction()
op = instruction.opcode
if op == tac.OP.NOP:
return self._no_change(concrete_transformation, abstract_type)
elif op == tac.OP.ASSIGN:
return self._assign(concrete_transformation, abstract_type)
elif op == tac.OP.IMPORT:
return self._no_change(concrete_transformation, abstract_type)
elif op == tac.OP.BINARY:
return self._binary(concrete_transformation, abstract_type)
elif op == tac.OP.INPLACE:
assert False
elif op == tac.OP.CALL:
return self._call(concrete_transformation, abstract_type)
elif op == tac.OP.JUMP:
return self._no_change(concrete_transformation, abstract_type)
elif op == tac.OP.FOR:
assert False
elif op == tac.OP.RET:
assert False, "Function calls not supported"
elif op == tac.OP.DEL:
return self._no_change(concrete_transformation, abstract_type)
else:
assert False, "Unknown Three Address Code instruction in %s" % str(instruction)
def equiv_type(self, abstract_type1, abstract_type2):
# Note: In the current implementation this has little use,
# since in the chaotic iterations we really need to traverse each edge just once
if z3_utils.sat_formula(z3.And(abstract_type1.formula(), z3.Not(abstract_type2.formula()))):
return False
if z3_utils.sat_formula(z3.And(abstract_type2.formula(), z3.Not(abstract_type1.formula()))):
return False
return True
def join(self, abstract_type1, abstract_type2):
return AbstractType(z3.Or(abstract_type1.formula(), abstract_type2.formula()))
def _binary_op_constraint(self, program_location):
op = program_location.instruction().op
operands = program_location.instruction().uses
all_operands_numeric_formula = z3.And(*(self._numeric_rel.has_type_of_formula(operand, program_location)
for operand in operands))
all_operands_string_formula = z3.And(*(self._string_rel.has_type_of_formula(operand, program_location)
for operand in operands))
all_operands_bool_formula = z3.And(*(self._bool_rel.has_type_of_formula(operand, program_location)
for operand in operands))
if op in ['**', '*', '//', '/', '%', '-', '<<', '>>']:
return all_operands_numeric_formula
elif op == '+':
return z3.Or(all_operands_numeric_formula, all_operands_string_formula)
elif op in ['&', '|', '^']:
return all_operands_bool_formula
else:
assert False, "Unknown type safety: op %s of instruction %s" % (op, program_location)
def _call_constraints(self, program_location):
instruction = program_location.instruction()
function_name = instruction.func
args = instruction.uses[1:] # TODO: add kargs (see TAC)
all_args_bool_formula = z3.And(*(self._bool_rel.has_type_of_formula(operand, program_location)
for operand in args))
if function_name == 'not':
print(all_args_bool_formula)
return all_args_bool_formula
assert False, "Unknown function call for type constraints"
def generate_safety_constraints(self, program_location):
instruction = program_location.instruction()
opcode = instruction.opcode
if opcode == tac.OP.NOP:
return True
elif opcode == tac.OP.ASSIGN:
return True
elif opcode == tac.OP.IMPORT:
return True
elif opcode == tac.OP.BINARY:
return self._binary_op_constraint(program_location)
elif opcode == tac.OP.INPLACE:
assert False
elif opcode == tac.OP.CALL:
return self._call_constraints(program_location)
elif opcode == tac.OP.JUMP:
# TODO: not supporting implicit conversion to bool
return self._bool_rel.has_type_of_formula(program_location.instruction().uses[0], program_location)
elif opcode == tac.OP.FOR:
assert False
elif opcode == tac.OP.RET:
if instruction.uses[0] == 'None':
return True
assert False, "Function calls not supported %s" % str(instruction)
elif opcode == tac.OP.DEL:
return True
else:
assert False, "Unknown Three Address Code instruction in %s" % str(instruction)
def get_types_exclusion_theory(self):
types_exclusion_theory = set()
for program_location in self._cfg.all_locations():
for var_name in self._cfg.program_vars():
# TODO: should be more fine-grained when we support subtyping
for possible_type1, possible_type2 in zip(self._possible_type_relations, self._possible_type_relations):
if possible_type1 != possible_type2:
exclusion_statement = z3.Not(z3.And(possible_type1.has_type_of_formula(var_name, program_location),
possible_type1.has_type_of_formula(var_name, program_location)))
types_exclusion_theory.add(exclusion_statement)
return types_exclusion_theory
