Extracted method for remove id for assignment case

Author: Thalmann

pyt/liveness.py

@@ -35,23 +35,27 @@ def is_condition(self, cfg_node):
             return True
         return False
 
+    def remove_id_assignment(self, JOIN, cfg_node):
+        lvars = list()
+        try:
+            for expr in cfg_node.ast_node.targets:
+                vv = VarsVisitor()
+                vv.visit(expr)
+                lvars.extend(vv.result)
+        except AttributeError:  # If it is AugAssign
+            vv = VarsVisitor()
+            vv.visit(cfg_node.ast_node.target)
+            lvars.extend(vv.result)
+
+        for var in lvars:
+            if var in self.lattice.get_elements(JOIN):  # Check if var in JOIN
+                JOIN = JOIN ^ self.lattice.el2bv[var]
+        return JOIN
     def fixpointmethod(self, cfg_node):
 
         if isinstance(cfg_node, EntryExitNode) and 'Exit' in cfg_node.label:
             constraint_table[cfg_node] = 0
         elif isinstance(cfg_node, AssignmentNode):
-            lvars = list()
-            try:
-                for expr in cfg_node.ast_node.targets:
-                    vv = VarsVisitor()
-                    vv.visit(expr)
-                    lvars.extend(vv.result)
-            except AttributeError:
-                if cfg_node.ast_node:
-                    vv = VarsVisitor()
-                    vv.visit(cfg_node.ast_node.value)
-                    lvars.extend(vv.result)
-
             JOIN = self.join(cfg_node)
 
             for var in lvars:
@@ -61,6 +65,7 @@ def fixpointmethod(self, cfg_node):
             for var in cfg_node.right_hand_side_variables:
                 JOIN = JOIN | self.lattice.el2bv[var]
 
+            JOIN = self.remove_id_assignment(JOIN, cfg_node)
             constraint_table[cfg_node] = JOIN
         elif self.is_condition(cfg_node):