Python: Remove points-to to from ControlFlowNode

Moves the existing points-to predicates to the newly added class
`ControlFlowNodeWithPointsTo` which resides in the `LegacyPointsTo`
module.

(Existing code that uses these predicates should import this module, and
references to `ControlFlowNode` should be changed to
`ControlFlowNodeWithPointsTo`.)

Also updates all existing points-to based code to do just this.

python/ql/src/analysis/Consistency.ql

@@ -5,6 +5,7 @@
  */
 
 import python
+private import LegacyPointsTo
 import analysis.DefinitionTracking
 
 predicate uniqueness_error(int number, string what, string problem) {
@@ -208,18 +209,22 @@ predicate function_object_consistency(string clsname, string problem, string wha
 predicate multiple_origins_per_object(Object obj) {
   not obj.isC() and
   not obj instanceof ModuleObject and
-  exists(ControlFlowNode use, Context ctx |
+  exists(ControlFlowNodeWithPointsTo use, Context ctx |
     strictcount(ControlFlowNode orig | use.refersTo(ctx, obj, _, orig)) > 1
   )
 }
 
-predicate intermediate_origins(ControlFlowNode use, ControlFlowNode inter, Object obj) {
+predicate intermediate_origins(
+  ControlFlowNodeWithPointsTo use, ControlFlowNodeWithPointsTo inter, Object obj
+) {
   exists(ControlFlowNode orig, Context ctx | not inter = orig |
     use.refersTo(ctx, obj, _, inter) and
     inter.refersTo(ctx, obj, _, orig) and
     // It can sometimes happen that two different modules (e.g. cPickle and Pickle)
     // have the same attribute, but different origins.
-    not strictcount(Object val | inter.(AttrNode).getObject().refersTo(val)) > 1
+    not strictcount(Object val |
+      inter.(AttrNode).getObject().(ControlFlowNodeWithPointsTo).refersTo(val)
+    ) > 1
   )
 }
 

python/ql/src/analysis/Efficiency.ql

@@ -4,6 +4,7 @@
  */
 
 import python
+private import LegacyPointsTo
 import semmle.python.pointsto.PointsTo
 import semmle.python.pointsto.PointsToContext
 
@@ -18,11 +19,11 @@ predicate trivial(ControlFlowNode f) {
 from int interesting_facts, int interesting_facts_in_source, int total_size, float efficiency
 where
   interesting_facts =
-    strictcount(ControlFlowNode f, Object value, ClassObject cls |
+    strictcount(ControlFlowNodeWithPointsTo f, Object value, ClassObject cls |
       f.refersTo(value, cls, _) and not trivial(f)
     ) and
   interesting_facts_in_source =
-    strictcount(ControlFlowNode f, Object value, ClassObject cls |
+    strictcount(ControlFlowNodeWithPointsTo f, Object value, ClassObject cls |
       f.refersTo(value, cls, _) and
       not trivial(f) and
       exists(f.getScope().getEnclosingModule().getFile().getRelativePath())

python/ql/src/analysis/ImportFailure.ql

@@ -7,6 +7,7 @@
  */
 
 import python
+private import LegacyPointsTo
 
 ImportExpr alternative_import(ImportExpr ie) {
   exists(Alias thisalias, Alias otheralias |
@@ -62,7 +63,10 @@ class VersionTest extends ControlFlowNode {
   VersionTest() {
     exists(string name |
       name.matches("%version%") and
-      this.(CompareNode).getAChild+().pointsTo(Module::named("sys").attr(name))
+      this.(CompareNode)
+          .getAChild+()
+          .(ControlFlowNodeWithPointsTo)
+          .pointsTo(Module::named("sys").attr(name))
     )
   }
 

python/ql/src/analysis/PointsToFailure.ql

@@ -9,7 +9,8 @@
  */
 
 import python
+private import LegacyPointsTo
 
 from Expr e
-where exists(ControlFlowNode f | f = e.getAFlowNode() | not f.refersTo(_))
+where exists(ControlFlowNodeWithPointsTo f | f = e.getAFlowNode() | not f.refersTo(_))
 select e, "Expression does not 'point-to' any object."

python/ql/src/analysis/TypeInferenceFailure.ql

@@ -8,8 +8,9 @@
  */
 
 import python
+private import LegacyPointsTo
 
-from ControlFlowNode f, Object o
+from ControlFlowNodeWithPointsTo f, Object o
 where
   f.refersTo(o) and
   not f.refersTo(o, _, _)