C++: Add a new dataflow consistency test.

MathiasVP · MathiasVP · commit 478f2dca3b4a · 2023-04-27T18:39:41.000+01:00
diff --git a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImplConsistency.qll b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImplConsistency.qll
@@ -58,6 +58,9 @@ module Consistency {
     predicate uniqueParameterNodePositionExclude(DataFlowCallable c, ParameterPosition pos, Node p) {
       none()
     }
+
+    /** Holds if `n` should be excluded from the consistency test `identityLocalStep`. */
+    predicate identityLocalStepExclude(Node n) { none() }
   }
 
   private class RelevantNode extends Node {
@@ -287,4 +290,10 @@ module Consistency {
     not exists(unique(ContentApprox approx | approx = getContentApprox(c))) and
     msg = "Non-unique content approximation."
   }
+
+  query predicate identityLocalStep(Node n, string msg) {
+    simpleLocalFlowStep(n, n) and
+    not any(ConsistencyConfiguration c).identityLocalStepExclude(n) and
+    msg = "Node steps to itself"
+  }
 }

Original file line number	Diff line number	Diff line change
`@@ -58,6 +58,9 @@ module Consistency {`
`58`	`58`	`predicate uniqueParameterNodePositionExclude(DataFlowCallable c, ParameterPosition pos, Node p) {`
`59`	`59`	`none()`
`60`	`60`	`}`
	`61`	`+`
	`62`	+ /** Holds if `n` should be excluded from the consistency test `identityLocalStep`. */
	`63`	`+ predicate identityLocalStepExclude(Node n) { none() }`
`61`	`64`	`}`
`62`	`65`
`63`	`66`	`private class RelevantNode extends Node {`
`@@ -287,4 +290,10 @@ module Consistency {`
`287`	`290`	`not exists(unique(ContentApprox approx \| approx = getContentApprox(c))) and`
`288`	`291`	`msg = "Non-unique content approximation."`
`289`	`292`	`}`
	`293`	`+`
	`294`	`+ query predicate identityLocalStep(Node n, string msg) {`
	`295`	`+ simpleLocalFlowStep(n, n) and`
	`296`	`+ not any(ConsistencyConfiguration c).identityLocalStepExclude(n) and`
	`297`	`+ msg = "Node steps to itself"`
	`298`	`+ }`
`290`	`299`	`}`