Merge pull request github#4923 from hvitved/csharp/ssa/refactor

C#: SSA refactorings

Author: hvitved

csharp/ql/src/semmle/code/csharp/commons/ConsistencyChecks.qll

@@ -49,7 +49,7 @@ module SsaChecks {
     exists(Definition def, BasicBlock bb, ControlFlow::Node rnode, ControlFlow::Node dnode, int i |
       def.getAReadAtNode(rnode) = read
     |
-      def.definesAt(bb, i) and
+      def.definesAt(_, bb, i) and
       dnode = bb.getNode(max(int j | j = i or j = 0)) and
       not dnode.dominates(rnode)
     ) and

csharp/ql/src/semmle/code/csharp/controlflow/BasicBlocks.qll

@@ -377,7 +377,17 @@ private predicate entryBB(BasicBlock bb) {
  * an annotated exit node.
  */
 class AnnotatedExitBasicBlock extends BasicBlock {
-  AnnotatedExitBasicBlock() { this.getANode() instanceof ControlFlow::Nodes::AnnotatedExitNode }
+  private boolean isNormal;
+
+  AnnotatedExitBasicBlock() {
+    this.getANode() =
+      any(ControlFlow::Nodes::AnnotatedExitNode n |
+        if n.isNormal() then isNormal = true else isNormal = false
+      )
+  }
+
+  /** Holds if this block represents a normal exit. */
+  predicate isNormal() { isNormal = true }
 }
 
 /**

csharp/ql/src/semmle/code/csharp/controlflow/ControlFlowGraph.qll

@@ -270,7 +270,7 @@ module ControlFlow {
       /** Gets the callable that this exit applies to. */
       Callable getCallable() { result = c }
 
-      /** Holds if this node represent a normal exit. */
+      /** Holds if this node represents a normal exit. */
       predicate isNormal() { normal = true }
 
       override BasicBlocks::AnnotatedExitBlock getBasicBlock() {

csharp/ql/src/semmle/code/csharp/controlflow/Guards.qll

@@ -621,8 +621,7 @@ private Ssa::Definition getAnSsaQualifier(Expr e, ControlFlow::Node cfn) {
 }
 
 private AssignableAccess getATrackedAccess(Ssa::Definition def, ControlFlow::Node cfn) {
-  result = def.getAReadAtNode(cfn) and
-  not def instanceof Ssa::ImplicitUntrackedDefinition
+  result = def.getAReadAtNode(cfn)
   or
   result = def.(Ssa::ExplicitDefinition).getADefinition().getTargetAccess() and
   cfn = def.getControlFlowNode()