C++: Ensure that 'argumentOf' does not map to multiple argument positions.

Author: MathiasVP

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

@@ -382,7 +382,7 @@ private class SideEffectArgumentNode extends ArgumentNode, SideEffectOperandNode
     exists(int indirectionIndex |
       pos = TIndirectionPosition(argumentIndex, pragma[only_bind_into](indirectionIndex)) and
       this.getCallInstruction() = dfCall.asCallInstruction() and
-      super.hasAddressOperandAndIndirectionIndex(_, pragma[only_bind_into](indirectionIndex))
+      super.hasAddressOperandAndIndirectionIndex(arg, pragma[only_bind_into](indirectionIndex))
     )
   }
 }

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

@@ -757,9 +757,11 @@ class SsaIteratorNode extends Node, TSsaIteratorNode {
 class SideEffectOperandNode extends Node instanceof IndirectOperand {
   CallInstruction call;
   int argumentIndex;
+  ArgumentOperand arg;
 
   SideEffectOperandNode() {
-    IndirectOperand.super.hasOperandAndIndirectionIndex(call.getArgumentOperand(argumentIndex), _)
+    arg = call.getArgumentOperand(argumentIndex) and
+    IndirectOperand.super.hasOperandAndIndirectionIndex(arg, _)
   }
 
   CallInstruction getCallInstruction() { result = call }