def parse_expression(expression, caller_context):
"""
Returns:
str: expression
"""
# Expression
# = Expression ('++' | '--')
# | NewExpression
# | IndexAccess
# | MemberAccess
# | FunctionCall
# | '(' Expression ')'
# | ('!' | '~' | 'delete' | '++' | '--' | '+' | '-') Expression
# | Expression '**' Expression
# | Expression ('*' | '/' | '%') Expression
# | Expression ('+' | '-') Expression
# | Expression ('<<' | '>>') Expression
# | Expression '&' Expression
# | Expression '^' Expression
# | Expression '|' Expression
# | Expression ('<' | '>' | '<=' | '>=') Expression
# | Expression ('==' | '!=') Expression
# | Expression '&&' Expression
# | Expression '||' Expression
# | Expression '?' Expression ':' Expression
# | Expression ('=' | '|=' | '^=' | '&=' | '<<=' | '>>=' | '+=' | '-=' | '*=' | '/=' | '%=') Expression
# | PrimaryExpression
# The AST naming does not follow the spec
name = expression[caller_context.get_key()]
is_compact_ast = caller_context.is_compact_ast
if name == 'UnaryOperation':
if is_compact_ast:
attributes = expression
else:
attributes = expression['attributes']
assert 'prefix' in attributes
operation_type = UnaryOperationType.get_type(attributes['operator'],
attributes['prefix'])
if is_compact_ast:
expression = parse_expression(expression['subExpression'],
caller_context)
else:
assert len(expression['children']) == 1
expression = parse_expression(expression['children'][0],
caller_context)
unary_op = UnaryOperation(expression, operation_type)
return unary_op
elif name == 'BinaryOperation':
if is_compact_ast:
attributes = expression
else:
attributes = expression['attributes']
operation_type = BinaryOperationType.get_type(attributes['operator'])
if is_compact_ast:
left_expression = parse_expression(expression['leftExpression'],
caller_context)
right_expression = parse_expression(expression['rightExpression'],
caller_context)
else:
assert len(expression['children']) == 2
left_expression = parse_expression(expression['children'][0],
caller_context)
right_expression = parse_expression(expression['children'][1],
caller_context)
binary_op = BinaryOperation(left_expression, right_expression,
operation_type)
return binary_op
elif name == 'FunctionCall':
return parse_call(expression, caller_context)
elif name == 'TupleExpression':
"""
For expression like
(a,,c) = (1,2,3)
the AST provides only two children in the left side
We check the type provided (tuple(uint256,,uint256))
To determine that there is an empty variable
Otherwhise we would not be able to determine that
a = 1, c = 3, and 2 is lost
Note: this is only possible with Solidity >= 0.4.12
"""
if is_compact_ast:
expressions = [
parse_expression(e, caller_context) if e else None
for e in expression['components']
]
else:
if 'children' not in expression:
attributes = expression['attributes']
components = attributes['components']
expressions = [
parse_expression(c, caller_context) if c else None
for c in components
]
else:
expressions = [
parse_expression(e, caller_context)
for e in expression['children']
]
# Add none for empty tuple items
if "attributes" in expression:
if "type" in expression['attributes']:
t = expression['attributes']['type']
if ',,' in t or '(,' in t or ',)' in t:
t = t[len('tuple('):-1]
elems = t.split(',')
for idx in range(len(elems)):
if elems[idx] == '':
expressions.insert(idx, None)
t = TupleExpression(expressions)
return t
elif name == 'Conditional':
if is_compact_ast:
if_expression = parse_expression(expression['condition'],
caller_context)
then_expression = parse_expression(expression['trueExpression'],
caller_context)
else_expression = parse_expression(expression['falseExpression'],
caller_context)
else:
children = expression['children']
assert len(children) == 3
if_expression = parse_expression(children[0], caller_context)
then_expression = parse_expression(children[1], caller_context)
else_expression = parse_expression(children[2], caller_context)
conditional = ConditionalExpression(if_expression, then_expression,
else_expression)
return conditional
elif name == 'Assignment':
if is_compact_ast:
left_expression = parse_expression(expression['leftHandSide'],
caller_context)
right_expression = parse_expression(expression['rightHandSide'],
caller_context)
operation_type = AssignmentOperationType.get_type(
expression['operator'])
operation_return_type = expression['typeDescriptions'][
'typeString']
else:
attributes = expression['attributes']
children = expression['children']
assert len(expression['children']) == 2
left_expression = parse_expression(children[0], caller_context)
right_expression = parse_expression(children[1], caller_context)
operation_type = AssignmentOperationType.get_type(
attributes['operator'])
operation_return_type = attributes['type']
assignement = AssignmentOperation(left_expression, right_expression,
operation_type,
operation_return_type)
return assignement
elif name == 'Literal':
assert 'children' not in expression
if is_compact_ast:
value = expression['value']
if value:
if 'subdenomination' in expression and expression[
'subdenomination']:
value = str(
convert_subdenomination(value,
expression['subdenomination']))
elif not value and value != "":
value = '0x' + expression['hexValue']
type = expression['typeDescriptions']['typeString']
# Length declaration for array was None until solc 0.5.5
if type is None:
if expression['kind'] == 'number':
type = 'int_const'
else:
value = expression['attributes']['value']
if value:
if 'subdenomination' in expression['attributes'] and expression[
'attributes']['subdenomination']:
value = str(
convert_subdenomination(
value,
expression['attributes']['subdenomination']))
elif value is None:
# for literal declared as hex
# see https://solidity.readthedocs.io/en/v0.4.25/types.html?highlight=hex#hexadecimal-literals
assert 'hexvalue' in expression['attributes']
value = '0x' + expression['attributes']['hexvalue']
type = expression['attributes']['type']
if type is None:
if value.isdecimal():
type = ElementaryType('uint256')
else:
type = ElementaryType('string')
elif type.startswith('int_const '):
type = ElementaryType('uint256')
elif type.startswith('bool'):
type = ElementaryType('bool')
elif type.startswith('address'):
type = ElementaryType('address')
else:
type = ElementaryType('string')
literal = Literal(value, type)
return literal
elif name == 'Identifier':
assert 'children' not in expression
t = None
if caller_context.is_compact_ast:
value = expression['name']
t = expression['typeDescriptions']['typeString']
else:
value = expression['attributes']['value']
if 'type' in expression['attributes']:
t = expression['attributes']['type']
if t:
found = re.findall(
'[struct|enum|function|modifier] \(([\[\] ()a-zA-Z0-9\.,_]*)\)',
t)
assert len(found) <= 1
if found:
value = value + '(' + found[0] + ')'
value = filter_name(value)
if 'referencedDeclaration' in expression:
referenced_declaration = expression['referencedDeclaration']
else:
referenced_declaration = None
var = find_variable(value, caller_context, referenced_declaration)
identifier = Identifier(var)
return identifier
elif name == 'IndexAccess':
if is_compact_ast:
index_type = expression['typeDescriptions']['typeString']
left = expression['baseExpression']
right = expression['indexExpression']
else:
index_type = expression['attributes']['type']
children = expression['children']
assert len(children) == 2
left = children[0]
right = children[1]
# IndexAccess is used to describe ElementaryTypeNameExpression
# if abi.decode is used
# For example, abi.decode(data, ...(uint[]) )
if right is None:
return _parse_elementary_type_name_expression(
left, is_compact_ast, caller_context)
left_expression = parse_expression(left, caller_context)
right_expression = parse_expression(right, caller_context)
index = IndexAccess(left_expression, right_expression, index_type)
return index
elif name == 'MemberAccess':
if caller_context.is_compact_ast:
member_name = expression['memberName']
member_type = expression['typeDescriptions']['typeString']
member_expression = parse_expression(expression['expression'],
caller_context)
else:
member_name = expression['attributes']['member_name']
member_type = expression['attributes']['type']
children = expression['children']
assert len(children) == 1
member_expression = parse_expression(children[0], caller_context)
if str(member_expression) == 'super':
super_name = parse_super_name(expression, is_compact_ast)
if isinstance(caller_context, Contract):
inheritance = caller_context.inheritance
else:
assert isinstance(caller_context, Function)
inheritance = caller_context.contract.inheritance
var = None
for father in inheritance:
try:
var = find_variable(super_name, father)
break
except VariableNotFound:
continue
if var is None:
raise VariableNotFound(
'Variable not found: {}'.format(super_name))
return SuperIdentifier(var)
member_access = MemberAccess(member_name, member_type,
member_expression)
if str(member_access) in SOLIDITY_VARIABLES_COMPOSED:
return Identifier(SolidityVariableComposed(str(member_access)))
return member_access
elif name == 'ElementaryTypeNameExpression':
return _parse_elementary_type_name_expression(expression,
is_compact_ast,
caller_context)
# NewExpression is not a root expression, it's always the child of another expression
elif name == 'NewExpression':
if is_compact_ast:
type_name = expression['typeName']
else:
children = expression['children']
assert len(children) == 1
type_name = children[0]
if type_name[caller_context.get_key()] == 'ArrayTypeName':
depth = 0
while type_name[caller_context.get_key()] == 'ArrayTypeName':
# Note: dont conserve the size of the array if provided
# We compute it directly
if is_compact_ast:
type_name = type_name['baseType']
else:
type_name = type_name['children'][0]
depth += 1
if type_name[caller_context.get_key()] == 'ElementaryTypeName':
if is_compact_ast:
array_type = ElementaryType(type_name['name'])
else:
array_type = ElementaryType(
type_name['attributes']['name'])
elif type_name[caller_context.get_key()] == 'UserDefinedTypeName':
if is_compact_ast:
array_type = parse_type(UnknownType(type_name['name']),
caller_context)
else:
array_type = parse_type(
UnknownType(type_name['attributes']['name']),
caller_context)
elif type_name[caller_context.get_key()] == 'FunctionTypeName':
array_type = parse_type(type_name, caller_context)
else:
raise ParsingError('Incorrect type array {}'.format(type_name))
array = NewArray(depth, array_type)
return array
if type_name[caller_context.get_key()] == 'ElementaryTypeName':
if is_compact_ast:
elem_type = ElementaryType(type_name['name'])
else:
elem_type = ElementaryType(type_name['attributes']['name'])
new_elem = NewElementaryType(elem_type)
return new_elem
assert type_name[caller_context.get_key()] == 'UserDefinedTypeName'
if is_compact_ast:
contract_name = type_name['name']
else:
contract_name = type_name['attributes']['name']
new = NewContract(contract_name)
return new
elif name == 'ModifierInvocation':
if is_compact_ast:
called = parse_expression(expression['modifierName'],
caller_context)
arguments = []
if expression['arguments']:
arguments = [
parse_expression(a, caller_context)
for a in expression['arguments']
]
else:
children = expression['children']
called = parse_expression(children[0], caller_context)
arguments = [
parse_expression(a, caller_context) for a in children[1::]
]
call = CallExpression(called, arguments, 'Modifier')
return call
raise ParsingError('Expression not parsed %s' % name)
def parse_expression(expression: Dict, caller_context: CallerContext) -> "Expression":
# pylint: disable=too-many-nested-blocks,too-many-statements
"""
Returns:
str: expression
"""
# Expression
# = Expression ('++' | '--')
# | NewExpression
# | IndexAccess
# | MemberAccess
# | FunctionCall
# | '(' Expression ')'
# | ('!' | '~' | 'delete' | '++' | '--' | '+' | '-') Expression
# | Expression '**' Expression
# | Expression ('*' | '/' | '%') Expression
# | Expression ('+' | '-') Expression
# | Expression ('<<' | '>>') Expression
# | Expression '&' Expression
# | Expression '^' Expression
# | Expression '|' Expression
# | Expression ('<' | '>' | '<=' | '>=') Expression
# | Expression ('==' | '!=') Expression
# | Expression '&&' Expression
# | Expression '||' Expression
# | Expression '?' Expression ':' Expression
# | Expression ('=' | '|=' | '^=' | '&=' | '<<=' | '>>=' | '+=' | '-=' | '*=' | '/=' | '%=') Expression
# | PrimaryExpression
# The AST naming does not follow the spec
name = expression[caller_context.get_key()]
is_compact_ast = caller_context.is_compact_ast
src = expression["src"]
if name == "UnaryOperation":
if is_compact_ast:
attributes = expression
else:
attributes = expression["attributes"]
assert "prefix" in attributes
operation_type = UnaryOperationType.get_type(attributes["operator"], attributes["prefix"])
if is_compact_ast:
expression = parse_expression(expression["subExpression"], caller_context)
else:
assert len(expression["children"]) == 1
expression = parse_expression(expression["children"][0], caller_context)
unary_op = UnaryOperation(expression, operation_type)
unary_op.set_offset(src, caller_context.slither)
return unary_op
if name == "BinaryOperation":
if is_compact_ast:
attributes = expression
else:
attributes = expression["attributes"]
operation_type = BinaryOperationType.get_type(attributes["operator"])
if is_compact_ast:
left_expression = parse_expression(expression["leftExpression"], caller_context)
right_expression = parse_expression(expression["rightExpression"], caller_context)
else:
assert len(expression["children"]) == 2
left_expression = parse_expression(expression["children"][0], caller_context)
right_expression = parse_expression(expression["children"][1], caller_context)
binary_op = BinaryOperation(left_expression, right_expression, operation_type)
binary_op.set_offset(src, caller_context.slither)
return binary_op
if name in "FunctionCall":
return parse_call(expression, caller_context)
if name == "FunctionCallOptions":
# call/gas info are handled in parse_call
if is_compact_ast:
called = parse_expression(expression["expression"], caller_context)
else:
called = parse_expression(expression["children"][0], caller_context)
assert isinstance(called, (MemberAccess, NewContract, Identifier, TupleExpression))
return called
if name == "TupleExpression":
# For expression like
# (a,,c) = (1,2,3)
# the AST provides only two children in the left side
# We check the type provided (tuple(uint256,,uint256))
# To determine that there is an empty variable
# Otherwhise we would not be able to determine that
# a = 1, c = 3, and 2 is lost
#
# Note: this is only possible with Solidity >= 0.4.12
if is_compact_ast:
expressions = [
parse_expression(e, caller_context) if e else None for e in expression["components"]
]
else:
if "children" not in expression:
attributes = expression["attributes"]
components = attributes["components"]
expressions = [
parse_expression(c, caller_context) if c else None for c in components
]
else:
expressions = [parse_expression(e, caller_context) for e in expression["children"]]
# Add none for empty tuple items
if "attributes" in expression:
if "type" in expression["attributes"]:
t = expression["attributes"]["type"]
if ",," in t or "(," in t or ",)" in t:
t = t[len("tuple(") : -1]
elems = t.split(",")
for idx, _ in enumerate(elems):
if elems[idx] == "":
expressions.insert(idx, None)
t = TupleExpression(expressions)
t.set_offset(src, caller_context.slither)
return t
if name == "Conditional":
if is_compact_ast:
if_expression = parse_expression(expression["condition"], caller_context)
then_expression = parse_expression(expression["trueExpression"], caller_context)
else_expression = parse_expression(expression["falseExpression"], caller_context)
else:
children = expression["children"]
assert len(children) == 3
if_expression = parse_expression(children[0], caller_context)
then_expression = parse_expression(children[1], caller_context)
else_expression = parse_expression(children[2], caller_context)
conditional = ConditionalExpression(if_expression, then_expression, else_expression)
conditional.set_offset(src, caller_context.slither)
return conditional
if name == "Assignment":
if is_compact_ast:
left_expression = parse_expression(expression["leftHandSide"], caller_context)
right_expression = parse_expression(expression["rightHandSide"], caller_context)
operation_type = AssignmentOperationType.get_type(expression["operator"])
operation_return_type = expression["typeDescriptions"]["typeString"]
else:
attributes = expression["attributes"]
children = expression["children"]
assert len(expression["children"]) == 2
left_expression = parse_expression(children[0], caller_context)
right_expression = parse_expression(children[1], caller_context)
operation_type = AssignmentOperationType.get_type(attributes["operator"])
operation_return_type = attributes["type"]
assignement = AssignmentOperation(
left_expression, right_expression, operation_type, operation_return_type
)
assignement.set_offset(src, caller_context.slither)
return assignement
if name == "Literal":
subdenomination = None
assert "children" not in expression
if is_compact_ast:
value = expression["value"]
if value:
if "subdenomination" in expression and expression["subdenomination"]:
subdenomination = expression["subdenomination"]
elif not value and value != "":
value = "0x" + expression["hexValue"]
type_candidate = expression["typeDescriptions"]["typeString"]
# Length declaration for array was None until solc 0.5.5
if type_candidate is None:
if expression["kind"] == "number":
type_candidate = "int_const"
else:
value = expression["attributes"]["value"]
if value:
if (
"subdenomination" in expression["attributes"]
and expression["attributes"]["subdenomination"]
):
subdenomination = expression["attributes"]["subdenomination"]
elif value is None:
# for literal declared as hex
# see https://solidity.readthedocs.io/en/v0.4.25/types.html?highlight=hex#hexadecimal-literals
assert "hexvalue" in expression["attributes"]
value = "0x" + expression["attributes"]["hexvalue"]
type_candidate = expression["attributes"]["type"]
if type_candidate is None:
if value.isdecimal():
type_candidate = ElementaryType("uint256")
else:
type_candidate = ElementaryType("string")
elif type_candidate.startswith("int_const "):
type_candidate = ElementaryType("uint256")
elif type_candidate.startswith("bool"):
type_candidate = ElementaryType("bool")
elif type_candidate.startswith("address"):
type_candidate = ElementaryType("address")
else:
type_candidate = ElementaryType("string")
literal = Literal(value, type_candidate, subdenomination)
literal.set_offset(src, caller_context.slither)
return literal
if name == "Identifier":
assert "children" not in expression
t = None
if caller_context.is_compact_ast:
value = expression["name"]
t = expression["typeDescriptions"]["typeString"]
else:
value = expression["attributes"]["value"]
if "type" in expression["attributes"]:
t = expression["attributes"]["type"]
if t:
found = re.findall("[struct|enum|function|modifier] \(([\[\] ()a-zA-Z0-9\.,_]*)\)", t)
assert len(found) <= 1
if found:
value = value + "(" + found[0] + ")"
value = filter_name(value)
if "referencedDeclaration" in expression:
referenced_declaration = expression["referencedDeclaration"]
else:
referenced_declaration = None
var = find_variable(value, caller_context, referenced_declaration)
identifier = Identifier(var)
identifier.set_offset(src, caller_context.slither)
return identifier
if name == "IndexAccess":
if is_compact_ast:
index_type = expression["typeDescriptions"]["typeString"]
left = expression["baseExpression"]
right = expression.get("indexExpression", None)
else:
index_type = expression["attributes"]["type"]
children = expression["children"]
left = children[0]
right = children[1] if len(children) > 1 else None
# IndexAccess is used to describe ElementaryTypeNameExpression
# if abi.decode is used
# For example, abi.decode(data, ...(uint[]) )
if right is None:
ret = parse_expression(left, caller_context)
# Nested array are not yet available in abi.decode
if isinstance(ret, ElementaryTypeNameExpression):
old_type = ret.type
ret.type = ArrayType(old_type, None)
return ret
left_expression = parse_expression(left, caller_context)
right_expression = parse_expression(right, caller_context)
index = IndexAccess(left_expression, right_expression, index_type)
index.set_offset(src, caller_context.slither)
return index
if name == "MemberAccess":
if caller_context.is_compact_ast:
member_name = expression["memberName"]
member_type = expression["typeDescriptions"]["typeString"]
# member_type = parse_type(
# UnknownType(expression["typeDescriptions"]["typeString"]), caller_context
# )
member_expression = parse_expression(expression["expression"], caller_context)
else:
member_name = expression["attributes"]["member_name"]
member_type = expression["attributes"]["type"]
# member_type = parse_type(UnknownType(expression["attributes"]["type"]), caller_context)
children = expression["children"]
assert len(children) == 1
member_expression = parse_expression(children[0], caller_context)
if str(member_expression) == "super":
super_name = parse_super_name(expression, is_compact_ast)
var = find_variable(super_name, caller_context, is_super=True)
if var is None:
raise VariableNotFound("Variable not found: {}".format(super_name))
sup = SuperIdentifier(var)
sup.set_offset(src, caller_context.slither)
return sup
member_access = MemberAccess(member_name, member_type, member_expression)
member_access.set_offset(src, caller_context.slither)
if str(member_access) in SOLIDITY_VARIABLES_COMPOSED:
id_idx = Identifier(SolidityVariableComposed(str(member_access)))
id_idx.set_offset(src, caller_context.slither)
return id_idx
return member_access
if name == "ElementaryTypeNameExpression":
return _parse_elementary_type_name_expression(expression, is_compact_ast, caller_context)
# NewExpression is not a root expression, it's always the child of another expression
if name == "NewExpression":
if is_compact_ast:
type_name = expression["typeName"]
else:
children = expression["children"]
assert len(children) == 1
type_name = children[0]
if type_name[caller_context.get_key()] == "ArrayTypeName":
depth = 0
while type_name[caller_context.get_key()] == "ArrayTypeName":
# Note: dont conserve the size of the array if provided
# We compute it directly
if is_compact_ast:
type_name = type_name["baseType"]
else:
type_name = type_name["children"][0]
depth += 1
if type_name[caller_context.get_key()] == "ElementaryTypeName":
if is_compact_ast:
array_type = ElementaryType(type_name["name"])
else:
array_type = ElementaryType(type_name["attributes"]["name"])
elif type_name[caller_context.get_key()] == "UserDefinedTypeName":
if is_compact_ast:
array_type = parse_type(UnknownType(type_name["name"]), caller_context)
else:
array_type = parse_type(
UnknownType(type_name["attributes"]["name"]), caller_context
)
elif type_name[caller_context.get_key()] == "FunctionTypeName":
array_type = parse_type(type_name, caller_context)
else:
raise ParsingError("Incorrect type array {}".format(type_name))
array = NewArray(depth, array_type)
array.set_offset(src, caller_context.slither)
return array
if type_name[caller_context.get_key()] == "ElementaryTypeName":
if is_compact_ast:
elem_type = ElementaryType(type_name["name"])
else:
elem_type = ElementaryType(type_name["attributes"]["name"])
new_elem = NewElementaryType(elem_type)
new_elem.set_offset(src, caller_context.slither)
return new_elem
assert type_name[caller_context.get_key()] == "UserDefinedTypeName"
if is_compact_ast:
# Changed introduced in Solidity 0.8
# see https://github.com/crytic/slither/issues/794
# TODO explore more the changes introduced in 0.8 and the usage of pathNode/IdentifierPath
if "name" not in type_name:
assert "pathNode" in type_name and "name" in type_name["pathNode"]
contract_name = type_name["pathNode"]["name"]
else:
contract_name = type_name["name"]
else:
contract_name = type_name["attributes"]["name"]
new = NewContract(contract_name)
new.set_offset(src, caller_context.slither)
return new
if name == "ModifierInvocation":
if is_compact_ast:
called = parse_expression(expression["modifierName"], caller_context)
arguments = []
if expression.get("arguments", None):
arguments = [parse_expression(a, caller_context) for a in expression["arguments"]]
else:
children = expression["children"]
called = parse_expression(children[0], caller_context)
arguments = [parse_expression(a, caller_context) for a in children[1::]]
call = CallExpression(called, arguments, "Modifier")
call.set_offset(src, caller_context.slither)
return call
if name == "IndexRangeAccess":
# For now, we convert array slices to a direct array access
# As a result the generated IR will lose the slices information
# As far as I understand, array slice are only used in abi.decode
# https://solidity.readthedocs.io/en/v0.6.12/types.html
# TODO: Investigate array slices usage and implication for the IR
base = parse_expression(expression["baseExpression"], caller_context)
return base
# Introduced with solc 0.8
if name == "IdentifierPath":
if caller_context.is_compact_ast:
value = expression["name"]
if "referencedDeclaration" in expression:
referenced_declaration = expression["referencedDeclaration"]
else:
referenced_declaration = None
var = find_variable(value, caller_context, referenced_declaration)
identifier = Identifier(var)
identifier.set_offset(src, caller_context.slither)
return identifier
raise ParsingError("IdentifierPath not currently supported for the legacy ast")
raise ParsingError("Expression not parsed %s" % name)
