Improve slithIR RETURN conversion (close #89)

slither/slithir/convert.py

@@ -2,7 +2,7 @@ import logging
 
 from slither.core.declarations import (Contract, Enum, Event, SolidityFunction,
                                        Structure, SolidityVariableComposed, Function, SolidityVariable)
-from slither.core.expressions import Identifier, Literal
+from slither.core.expressions import Identifier, Literal, TupleExpression
 from slither.core.solidity_types import ElementaryType, UserDefinedType, MappingType, ArrayType, FunctionType
 from slither.core.variables.variable import Variable
 from slither.slithir.operations import (Assignment, Binary, BinaryType, Call,
@@ -667,18 +667,15 @@ def convert_expression(expression, node):
     # handle standlone expression
     # such as return true;
     from slither.core.cfg.node import NodeType
-    if isinstance(expression, Literal) and node.type == NodeType.RETURN:
+
-        result =  [Return(Constant(expression.value))]
-        return result
-    if isinstance(expression, Identifier) and node.type == NodeType.RETURN:
-        result =  [Return(expression.value)]
-        return result
     if isinstance(expression, Literal) and node.type in [NodeType.IF, NodeType.IFLOOP]:
         result =  [Condition(Constant(expression.value))]
         return result
     if isinstance(expression, Identifier) and node.type in [NodeType.IF, NodeType.IFLOOP]:
         result =  [Condition(expression.value)]
         return result
+
+
     visitor = ExpressionToSlithIR(expression, node)
     result = visitor.result()
 

slither/slithir/operations/return_operation.py

@@ -7,21 +7,27 @@ class Return(Operation):
        Return
        Only present as last operation in RETURN node
     """
-    def __init__(self, value):
+    def __init__(self, values):
         # Note: Can return None 
         # ex: return call()
         # where call() dont return
-        assert is_valid_rvalue(value) or isinstance(value, TupleVariable) or value == None
+        if not isinstance(values, list):
+            assert is_valid_rvalue(values) or isinstance(values, TupleVariable) or values == None
+            if not values is None:
+                values = [values]
+        else:
+            for value in values:
+                assert is_valid_rvalue(value) or isinstance(value, TupleVariable)
         super(Return, self).__init__()
-        self._value = value
+        self._values = values
 
     @property
     def read(self):
-        return [self.value]
+        return self.values
 
     @property
-    def value(self):
+    def values(self):
-        return self._value
+        return self._values
 
     def __str__(self):
-        return "RETURN {}".format(self.value)
+        return "RETURN {}".format(','.join(['{}'.format(x) for x in self.values]))

slither/visitors/slithir/expression_to_slithir.py

@@ -7,7 +7,7 @@ from slither.core.solidity_types.array_type import ArrayType
 from slither.slithir.operations import (Assignment, Binary, BinaryType, Delete,
                                         Index, InitArray, InternalCall, Member,
                                         NewArray, NewContract, NewStructure,
-                                        TypeConversion, Unary, Unpack)
+                                        TypeConversion, Unary, Unpack, Return)
 from slither.slithir.tmp_operations.argument import Argument
 from slither.slithir.tmp_operations.tmp_call import TmpCall
 from slither.slithir.tmp_operations.tmp_new_array import TmpNewArray
@@ -62,10 +62,13 @@ def convert_assignment(left, right, t, return_type):
 class ExpressionToSlithIR(ExpressionVisitor):
 
     def __init__(self, expression, node):
+        from slither.core.cfg.node import NodeType
         self._expression = expression
         self._node = node
         self._result = []
         self._visit_expression(self.expression)
+        if node.type == NodeType.RETURN:
+            self._result.append(Return(get(self.expression)))
         for ir in self._result:
             ir.set_node(node)