def convert_to_pop(ir, node):
"""
Convert pop operators
Return a list of 6 operations
"""
ret = []
arr = ir.destination
length = ReferenceVariable(node)
length.set_type(ElementaryType('uint256'))
ir_length = Length(arr, length)
ir_length.set_expression(ir.expression)
ir_length.set_node(ir.node)
ir_length.lvalue.points_to = arr
ret.append(ir_length)
val = TemporaryVariable(node)
ir_sub_1 = Binary(val, length, Constant("1", ElementaryType('uint256')),
BinaryType.SUBTRACTION)
ir_sub_1.set_expression(ir.expression)
ir_sub_1.set_node(ir.node)
ret.append(ir_sub_1)
element_to_delete = ReferenceVariable(node)
ir_assign_element_to_delete = Index(element_to_delete, arr, val,
ElementaryType('uint256'))
ir_length.lvalue.points_to = arr
element_to_delete.set_type(ElementaryType('uint256'))
ir_assign_element_to_delete.set_expression(ir.expression)
ir_assign_element_to_delete.set_node(ir.node)
ret.append(ir_assign_element_to_delete)
ir_delete = Delete(element_to_delete, element_to_delete)
ir_delete.set_expression(ir.expression)
ir_delete.set_node(ir.node)
ret.append(ir_delete)
length_to_assign = ReferenceVariable(node)
length_to_assign.set_type(ElementaryType('uint256'))
ir_length = Length(arr, length_to_assign)
ir_length.set_expression(ir.expression)
ir_length.lvalue.points_to = arr
ir_length.set_node(ir.node)
ret.append(ir_length)
ir_assign_length = Assignment(length_to_assign, val,
ElementaryType('uint256'))
ir_assign_length.set_expression(ir.expression)
ir_assign_length.set_node(ir.node)
ret.append(ir_assign_length)
return ret
def propagate_types(ir, node):
# propagate the type
using_for = node.function.contract.using_for
if isinstance(ir, OperationWithLValue):
# Force assignment in case of missing previous correct type
if not ir.lvalue.type:
if isinstance(ir, Assignment):
ir.lvalue.set_type(ir.rvalue.type)
elif isinstance(ir, Binary):
if BinaryType.return_bool(ir.type):
ir.lvalue.set_type(ElementaryType('bool'))
else:
ir.lvalue.set_type(ir.variable_left.type)
elif isinstance(ir, Delete):
# nothing to propagate
pass
elif isinstance(ir, LibraryCall):
return convert_type_library_call(ir, ir.destination)
elif isinstance(ir, HighLevelCall):
t = ir.destination.type
# Temporary operation (they are removed later)
if t is None:
return
if isinstance(t, ElementaryType) and t.name == 'address':
if can_be_solidity_func(ir):
return convert_to_solidity_func(ir)
# convert library
if t in using_for or '*' in using_for:
new_ir = convert_to_library(ir, node, using_for)
if new_ir:
return new_ir
if isinstance(t, UserDefinedType):
# UserdefinedType
t_type = t.type
if isinstance(t_type, Contract):
contract = node.slither.get_contract_from_name(t_type.name)
return convert_type_of_high_and_internal_level_call(ir, contract)
# Convert HighLevelCall to LowLevelCall
if isinstance(t, ElementaryType) and t.name == 'address':
if ir.destination.name == 'this':
return convert_type_of_high_and_internal_level_call(ir, node.function.contract)
if can_be_low_level(ir):
return convert_to_low_level(ir)
# Convert push operations
# May need to insert a new operation
# Which leads to return a list of operation
if isinstance(t, ArrayType) or (isinstance(t, ElementaryType) and t.type == 'bytes'):
if ir.function_name == 'push' and len(ir.arguments) == 1:
return convert_to_push(ir, node)
if ir.function_name == 'pop' and len(ir.arguments) == 0:
return convert_to_pop(ir, node)
elif isinstance(ir, Index):
if isinstance(ir.variable_left.type, MappingType):
ir.lvalue.set_type(ir.variable_left.type.type_to)
elif isinstance(ir.variable_left.type, ArrayType):
ir.lvalue.set_type(ir.variable_left.type.type)
elif isinstance(ir, InitArray):
length = len(ir.init_values)
t = ir.init_values[0].type
ir.lvalue.set_type(ArrayType(t, length))
elif isinstance(ir, InternalCall):
# if its not a tuple, return a singleton
if ir.function is None:
convert_type_of_high_and_internal_level_call(ir, node.function.contract)
return_type = ir.function.return_type
if return_type:
if len(return_type) == 1:
ir.lvalue.set_type(return_type[0])
elif len(return_type) > 1:
ir.lvalue.set_type(return_type)
else:
ir.lvalue = None
elif isinstance(ir, InternalDynamicCall):
# if its not a tuple, return a singleton
return_type = ir.function_type.return_type
if return_type:
if len(return_type) == 1:
ir.lvalue.set_type(return_type[0])
else:
ir.lvalue.set_type(return_type)
else:
ir.lvalue = None
elif isinstance(ir, LowLevelCall):
# Call are not yet converted
# This should not happen
assert False
elif isinstance(ir, Member):
# TODO we should convert the reference to a temporary if the member is a length or a balance
if ir.variable_right == 'length' and not isinstance(ir.variable_left, Contract) and isinstance(
ir.variable_left.type, (ElementaryType, ArrayType)):
length = Length(ir.variable_left, ir.lvalue)
length.set_expression(ir.expression)
length.lvalue.points_to = ir.variable_left
length.set_node(ir.node)
return length
if ir.variable_right == 'balance' and not isinstance(ir.variable_left, Contract) and isinstance(
ir.variable_left.type, ElementaryType):
b = Balance(ir.variable_left, ir.lvalue)
b.set_expression(ir.expression)
b.set_node(ir.node)
return b
if ir.variable_right == 'selector' and isinstance(ir.variable_left.type, Function):
assignment = Assignment(ir.lvalue,
Constant(str(get_function_id(ir.variable_left.type.full_name))),
ElementaryType('bytes4'))
assignment.set_expression(ir.expression)
assignment.set_node(ir.node)
assignment.lvalue.set_type(ElementaryType('bytes4'))
return assignment
if isinstance(ir.variable_left, TemporaryVariable) and isinstance(ir.variable_left.type,
TypeInformation):
return _convert_type_contract(ir, node.function.slither)
left = ir.variable_left
t = None
if isinstance(left, (Variable, SolidityVariable)):
t = ir.variable_left.type
elif isinstance(left, (Contract, Enum, Structure)):
t = UserDefinedType(left)
# can be None due to temporary operation
if t:
if isinstance(t, UserDefinedType):
# UserdefinedType
type_t = t.type
if isinstance(type_t, Enum):
ir.lvalue.set_type(t)
elif isinstance(type_t, Structure):
elems = type_t.elems
for elem in elems:
if elem == ir.variable_right:
ir.lvalue.set_type(elems[elem].type)
else:
assert isinstance(type_t, Contract)
# Allow type propagtion as a Function
# Only for reference variables
# This allows to track the selector keyword
# We dont need to check for function collision, as solc prevents the use of selector
# if there are multiple functions with the same name
f = next((f for f in type_t.functions if f.name == ir.variable_right), None)
if f:
ir.lvalue.set_type(f)
else:
# Allow propgation for variable access through contract's nale
# like Base_contract.my_variable
v = next((v for v in type_t.state_variables if v.name == ir.variable_right), None)
if v:
ir.lvalue.set_type(v.type)
elif isinstance(ir, NewArray):
ir.lvalue.set_type(ir.array_type)
elif isinstance(ir, NewContract):
contract = node.slither.get_contract_from_name(ir.contract_name)
ir.lvalue.set_type(UserDefinedType(contract))
elif isinstance(ir, NewElementaryType):
ir.lvalue.set_type(ir.type)
elif isinstance(ir, NewStructure):
ir.lvalue.set_type(UserDefinedType(ir.structure))
elif isinstance(ir, Push):
# No change required
pass
elif isinstance(ir, Send):
ir.lvalue.set_type(ElementaryType('bool'))
elif isinstance(ir, SolidityCall):
if ir.function.name == 'type(address)':
ir.function.return_type = [TypeInformation(ir.arguments[0])]
return_type = ir.function.return_type
if len(return_type) == 1:
ir.lvalue.set_type(return_type[0])
elif len(return_type) > 1:
ir.lvalue.set_type(return_type)
elif isinstance(ir, TypeConversion):
ir.lvalue.set_type(ir.type)
elif isinstance(ir, Unary):
ir.lvalue.set_type(ir.rvalue.type)
elif isinstance(ir, Unpack):
types = ir.tuple.type.type
idx = ir.index
t = types[idx]
ir.lvalue.set_type(t)
elif isinstance(ir,
(Argument, TmpCall, TmpNewArray, TmpNewContract, TmpNewStructure, TmpNewElementaryType)):
# temporary operation; they will be removed
pass
else:
raise SlithIRError('Not handling {} during type propgation'.format(type(ir)))