DataFlow: Cached second level scope.

Author: MathiasVP

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

@@ -1119,9 +1119,10 @@ module MakeImpl<LocationSig Location, InputSig<Location> Lang> {
 
     pragma[nomagic]
     private SndLevelScopeOption getScope(RetNodeEx ret) {
-      result = SndLevelScopeOption::some(getSecondLevelScope(ret.asNode()))
+      result = SndLevelScopeOption::some(getSecondLevelScopeCached(ret.asNode()))
       or
-      result instanceof SndLevelScopeOption::None and not exists(getSecondLevelScope(ret.asNode()))
+      result instanceof SndLevelScopeOption::None and
+      not exists(getSecondLevelScopeCached(ret.asNode()))
     }
 
     pragma[nomagic]

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

@@ -616,6 +616,9 @@ module MakeImplCommon<LocationSig Location, InputSig<Location> Lang> {
     cached
     predicate forceCachingInSameStage() { any() }
 
+    cached
+    DataFlowSecondLevelScope getSecondLevelScopeCached(Node n) { result = getSecondLevelScope(n) }
+
     cached
     predicate nodeEnclosingCallable(Node n, DataFlowCallable c) { c = nodeGetEnclosingCallable(n) }