def walk_bv_to_bv(self, formula, args, **kwargs):
#pylint: disable=unused-argument
# We check that all children are BV and the same size
target_bv_type = BVType(formula.bv_width())
for a in args:
if not a == target_bv_type:
return None
return target_bv_type
def walk_bv_rotate(self, formula, args, **kwargs):
#pylint: disable=unused-argument
target_width = formula.bv_width()
#if target_width < formula.bv_rotation_step() or target_width < 0:
if target_width < 0:
return None
if target_width != args[0].width:
return None
return BVType(target_width)
def is_bv_constant(self, value=None, width=None):
"""Test whether the formula is a BitVector constant.
Optionally, check that the constant has the given value.
"""
if value is None and width is None:
return self.node_type() == BV_CONSTANT
if width is None:
return self.is_constant(value=value)
else:
return self.is_constant(_type=BVType(width=width), value=value)
def walk_bv_concat(self, formula, args, **kwargs):
# Width of BV operators are computed at construction time.
# The type-checker only verifies that they are indeed
# correct.
try:
l_width = args[0].width
r_width = args[1].width
target_width = formula.bv_width()
except AttributeError:
return None
if not l_width + r_width == target_width:
return None
return BVType(target_width)
def constant_type(self):
"""Return the type of the Constant."""
if self.node_type() == INT_CONSTANT:
return INT
elif self.node_type() == REAL_CONSTANT:
return REAL
elif self.node_type() == BOOL_CONSTANT:
return BOOL
elif self.node_type() == STR_CONSTANT:
return STRING
else:
assert self.node_type() == BV_CONSTANT,\
"Unsupported method constant_type '%s'" % self
return BVType(width=self.bv_width())
def walk_bv_extract(self, formula, args, **kwargs):
arg = args[0]
if not arg.is_bv_type():
return None
base_width = arg.width
target_width = formula.bv_width()
start = formula.bv_extract_start()
end = formula.bv_extract_end()
if start >= base_width or end >= base_width:
return None
if base_width < target_width:
return None
if target_width != (end - start + 1):
return None
return BVType(target_width)
def walk_identity_bv(self, formula, args, **kwargs):
#pylint: disable=unused-argument
assert formula is not None
assert len(args) == 0
return BVType(formula.bv_width())
def walk_bv_extend(self, formula, args, **kwargs):
#pylint: disable=unused-argument
target_width = formula.bv_width()
if target_width < args[0].width or target_width < 0:
return None
return BVType(target_width)
def walk_bv_comp(self, formula, args, **kwargs):
# We check that all children are BV and the same size
a, b = args
if a != b or (not a.is_bv_type()):
return None
return BVType(1)