Merge pull request #12959 from MathiasVP/identity-consistency-check

DataFlow: Add an "identity-step" consistency check

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/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"
+  }
 }

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"
+  }
 }

cpp/ql/test/library-tests/dataflow/dataflow-tests/dataflow-consistency.expected

@@ -129,3 +129,4 @@ viableImplInCallContextTooLarge
 uniqueParameterNodeAtPosition
 uniqueParameterNodePosition
 uniqueContentApprox
+identityLocalStep

cpp/ql/test/library-tests/dataflow/dataflow-tests/dataflow-ir-consistency.expected

@@ -162,3 +162,4 @@ viableImplInCallContextTooLarge
 uniqueParameterNodeAtPosition
 uniqueParameterNodePosition
 uniqueContentApprox
+identityLocalStep

cpp/ql/test/library-tests/dataflow/fields/dataflow-consistency.expected

@@ -97,3 +97,4 @@ viableImplInCallContextTooLarge
 uniqueParameterNodeAtPosition
 uniqueParameterNodePosition
 uniqueContentApprox
+identityLocalStep

cpp/ql/test/library-tests/dataflow/fields/dataflow-ir-consistency.expected

@@ -71,4 +71,6 @@ private class MyConsistencyConfiguration extends ConsistencyConfiguration {
   }
 
   override predicate reverseReadExclude(Node n) { n.asExpr() = any(AwaitExpr ae).getExpr() }
+
+  override predicate identityLocalStepExclude(Node n) { this.missingLocationExclude(n) }
 }

cpp/ql/test/library-tests/syntax-zoo/dataflow-consistency.expected

@@ -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"
+  }
 }

cpp/ql/test/library-tests/syntax-zoo/dataflow-ir-consistency.expected

@@ -0,0 +1,7 @@
+identityLocalStep
+| test.cs:17:41:17:44 | this access | Node steps to itself |
+| test.cs:34:41:34:44 | this access | Node steps to itself |
+| test.cs:52:41:52:44 | this access | Node steps to itself |
+| test.cs:67:41:67:44 | this access | Node steps to itself |
+| test.cs:77:22:77:24 | this access | Node steps to itself |
+| test.cs:90:41:90:44 | this access | Node steps to itself |

csharp/ql/consistency-queries/DataFlowConsistency.ql

@@ -0,0 +1,2 @@
+identityLocalStep
+| Conditions.cs:133:17:133:22 | [Field1 (line 129): false] this access | Node steps to itself |

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

@@ -0,0 +1,7 @@
+identityLocalStep
+| SplittingStressTest.cs:172:16:172:16 | SSA phi read(b29) | Node steps to itself |
+| SplittingStressTest.cs:179:13:183:13 | [b1 (line 170): false] SSA phi read(b1) | Node steps to itself |
+| SplittingStressTest.cs:184:13:188:13 | [b2 (line 170): false] SSA phi read(b2) | Node steps to itself |
+| SplittingStressTest.cs:189:13:193:13 | [b3 (line 170): false] SSA phi read(b3) | Node steps to itself |
+| SplittingStressTest.cs:194:13:198:13 | [b4 (line 170): false] SSA phi read(b4) | Node steps to itself |
+| SplittingStressTest.cs:199:13:203:13 | [b5 (line 170): false] SSA phi read(b5) | Node steps to itself |

csharp/ql/test/experimental/ir/offbyone/CONSISTENCY/DataFlowConsistency.expected

@@ -0,0 +1,2 @@
+identityLocalStep
+| Test.cs:80:37:80:42 | this access | Node steps to itself |

csharp/ql/test/library-tests/cil/attributes/CONSISTENCY/DataFlowConsistency.expected

@@ -0,0 +1,2 @@
+identityLocalStep
+| GlobalDataFlow.cs:573:9:576:9 | SSA phi read(f) | Node steps to itself |

csharp/ql/test/library-tests/cil/consistency/CONSISTENCY/DataFlowConsistency.expected

@@ -0,0 +1,3 @@
+identityLocalStep
+| DefUse.cs:80:37:80:42 | this access | Node steps to itself |
+| Properties.cs:65:24:65:31 | this access | Node steps to itself |