Dataflow: Add language-specific predicate forceHighPrecision().

Author: aschackmull

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowPrivate.qll

@@ -240,6 +240,12 @@ predicate isUnreachableInCall(Node n, DataFlowCall call) { none() } // stub impl
 
 int accessPathLimit() { result = 5 }
 
+/**
+ * Holds if accesspaths with `c` at their head always should be tracked at high
+ * precision. This disables adaptive accesspath precision for such accesspaths.
+ */
+predicate forceHighPrecision(Content c) { none() }
+
 /** The unit type. */
 private newtype TUnit = TMkUnit()
 

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowPrivate.qll

@@ -466,6 +466,12 @@ predicate isUnreachableInCall(Node n, DataFlowCall call) { none() } // stub impl
 
 int accessPathLimit() { result = 5 }
 
+/**
+ * Holds if accesspaths with `c` at their head always should be tracked at high
+ * precision. This disables adaptive accesspath precision for such accesspaths.
+ */
+predicate forceHighPrecision(Content c) { none() }
+
 /** The unit type. */
 private newtype TUnit = TMkUnit()
 

csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll

@@ -1918,6 +1918,12 @@ private predicate viableConstantBooleanParamArg(
 
 int accessPathLimit() { result = 5 }
 
+/**
+ * Holds if accesspaths with `c` at their head always should be tracked at high
+ * precision. This disables adaptive accesspath precision for such accesspaths.
+ */
+predicate forceHighPrecision(Content c) { c instanceof ElementContent }
+
 /** The unit type. */
 private newtype TUnit = TMkUnit()
 

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPrivate.qll

@@ -1620,6 +1620,12 @@ predicate isImmutableOrUnobservable(Node n) { none() }
 
 int accessPathLimit() { result = 5 }
 
+/**
+ * Holds if accesspaths with `c` at their head always should be tracked at high
+ * precision. This disables adaptive accesspath precision for such accesspaths.
+ */
+predicate forceHighPrecision(Content c) { none() }
+
 /** Holds if `n` should be hidden from path explanations. */
 predicate nodeIsHidden(Node n) { none() }