Data flow: Cache known{Source,Sink}Model

Author: hvitved

shared/dataflow/codeql/dataflow/internal/DataFlowImpl.qll

@@ -1014,20 +1014,12 @@ module MakeImpl<LocationSig Location, InputSig<Location> Lang> {
 
     private predicate sourceModel(NodeEx node, string model) {
       sourceNode(node, _) and
-      exists(Node n | n = node.asNode() |
-        knownSourceModel(n, model)
-        or
-        not knownSourceModel(n, _) and model = ""
-      )
+      model = getSourceModel(node)
     }
 
     private predicate sinkModel(NodeEx node, string model) {
       sinkNode(node, _) and
-      exists(Node n | n = node.asNodeOrImplicitRead() |
-        knownSinkModel(n, model)
-        or
-        not knownSinkModel(n, _) and model = ""
-      )
+      model = getSinkModel(node)
     }
 
     bindingset[label1, label2]

shared/dataflow/codeql/dataflow/internal/DataFlowImplCommon.qll

@@ -1063,6 +1063,24 @@ module MakeImplCommon<LocationSig Location, InputSig<Location> Lang> {
       exists(n.asParamReturnNode())
     }
 
+    cached
+    string getSourceModel(NodeEx node) {
+      exists(Node n | n = node.asNode() |
+        knownSourceModel(n, result)
+        or
+        not knownSourceModel(n, _) and result = ""
+      )
+    }
+
+    cached
+    string getSinkModel(NodeEx node) {
+      exists(Node n | n = node.asNode() |
+        knownSinkModel(n, result)
+        or
+        not knownSinkModel(n, _) and result = ""
+      )
+    }
+
     cached
     predicate parameterNode(Node p, DataFlowCallable c, ParameterPosition pos) {
       isParameterNode(p, c, pos)