Merge pull request #13031 from hvitved/identity-consistency-check

C#: Remove local identity flow steps

csharp/ql/consistency-queries/DataFlowConsistency.ql

@@ -72,5 +72,5 @@ private class MyConsistencyConfiguration extends ConsistencyConfiguration {
 
   override predicate reverseReadExclude(Node n) { n.asExpr() = any(AwaitExpr ae).getExpr() }
 
-  override predicate identityLocalStepExclude(Node n) { n.getLocation().getFile().fromLibrary() }
+  override predicate identityLocalStepExclude(Node n) { none() }
 }

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

@@ -335,7 +335,8 @@ module LocalFlow {
     exists(ControlFlow::BasicBlock bb, int i |
       SsaImpl::lastRefBeforeRedefExt(def, bb, i, next.getDefinitionExt()) and
       def.definesAt(_, bb, i, _) and
-      def = getSsaDefinitionExt(nodeFrom)
+      def = getSsaDefinitionExt(nodeFrom) and
+      nodeFrom != next
     )
   }
 
@@ -414,7 +415,8 @@ module LocalFlow {
     ) {
       exists(CIL::BasicBlock bb, int i | CilSsaImpl::lastRefBeforeRedefExt(def, bb, i, next) |
         def.definesAt(_, bb, i, _) and
-        def = nodeFrom.(CilSsaDefinitionExtNode).getDefinition()
+        def = nodeFrom.(CilSsaDefinitionExtNode).getDefinition() and
+        def != next
         or
         nodeFrom = TCilExprNode(bb.getNode(i).(CIL::ReadAccess))
       )
@@ -440,7 +442,8 @@ module LocalFlow {
       exists(CIL::ReadAccess readFrom, CIL::ReadAccess readTo |
         CilSsaImpl::hasAdjacentReadsExt(def, readFrom, readTo) and
         nodeTo = TCilExprNode(readTo) and
-        nodeFrom = TCilExprNode(readFrom)
+        nodeFrom = TCilExprNode(readFrom) and
+        nodeFrom != nodeTo
       )
       or
       // Flow into phi (read) node
@@ -483,7 +486,8 @@ module LocalFlow {
     or
     hasNodePath(any(LocalExprStepConfiguration x), nodeFrom, nodeTo)
     or
-    ThisFlow::adjacentThisRefs(nodeFrom, nodeTo)
+    ThisFlow::adjacentThisRefs(nodeFrom, nodeTo) and
+    nodeFrom != nodeTo
     or
     ThisFlow::adjacentThisRefs(nodeFrom.(PostUpdateNode).getPreUpdateNode(), nodeTo)
     or
@@ -541,7 +545,8 @@ predicate simpleLocalFlowStep(Node nodeFrom, Node nodeTo) {
   exists(SsaImpl::DefinitionExt def |
     LocalFlow::localSsaFlowStepUseUse(def, nodeFrom, nodeTo) and
     not FlowSummaryImpl::Private::Steps::prohibitsUseUseFlow(nodeFrom, _) and
-    not LocalFlow::usesInstanceField(def)
+    not LocalFlow::usesInstanceField(def) and
+    nodeFrom != nodeTo
   )
   or
   // Flow into phi (read)/uncertain SSA definition node from read
@@ -880,7 +885,8 @@ private module Cached {
   predicate localFlowStepImpl(Node nodeFrom, Node nodeTo) {
     LocalFlow::localFlowStepCommon(nodeFrom, nodeTo)
     or
-    LocalFlow::localSsaFlowStepUseUse(_, nodeFrom, nodeTo)
+    LocalFlow::localSsaFlowStepUseUse(_, nodeFrom, nodeTo) and
+    nodeFrom != nodeTo
     or
     exists(SsaImpl::DefinitionExt def |
       LocalFlow::localSsaFlowStep(def, nodeFrom, nodeTo) and

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

@@ -1,7 +0,0 @@
-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/test/library-tests/controlflow/graph/CONSISTENCY/DataFlowConsistency.expected

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

csharp/ql/test/library-tests/controlflow/guards/CONSISTENCY/DataFlowConsistency.expected

@@ -1,2 +0,0 @@
-identityLocalStep
-| Splitting.cs:133:21:133:29 | [b (line 123): false] this access | Node steps to itself |

csharp/ql/test/library-tests/controlflow/splits/CONSISTENCY/DataFlowConsistency.expected

@@ -1,7 +0,0 @@
-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/library-tests/dataflow/defuse/CONSISTENCY/DataFlowConsistency.expected

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

csharp/ql/test/library-tests/dataflow/global/CONSISTENCY/DataFlowConsistency.expected

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

csharp/ql/test/library-tests/dataflow/ssa/CONSISTENCY/DataFlowConsistency.expected

@@ -1,3 +0,0 @@
-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 |

csharp/ql/test/query-tests/Nullness/CONSISTENCY/DataFlowConsistency.expected

@@ -1,4 +0,0 @@
-identityLocalStep
-| D.cs:320:17:320:25 | this access | Node steps to itself |
-| E.cs:123:21:123:24 | SSA phi read(x) | Node steps to itself |
-| E.cs:123:21:123:24 | SSA phi(i) | Node steps to itself |

csharp/ql/test/query-tests/Security Features/CWE-022/ZipSlip/CONSISTENCY/DataFlowConsistency.expected

@@ -1,2 +0,0 @@
-identityLocalStep
-| ZipSlip.cs:13:13:45:13 | SSA phi read(destDirectory) | Node steps to itself |