C++: Introduce operand dataflow node

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

@@ -13,6 +13,7 @@ private import semmle.code.cpp.models.interfaces.DataFlow
 
 private newtype TIRDataFlowNode =
   TInstructionNode(Instruction i) or
+  TOperandNode(Operand op) or
   TVariableNode(Variable var)
 
 /**
@@ -37,6 +38,9 @@ class Node extends TIRDataFlowNode {
   /** Gets the instruction corresponding to this node, if any. */
   Instruction asInstruction() { result = this.(InstructionNode).getInstruction() }
 
+  /** Gets the operands corresponding to this node, if any. */
+  Operand asOperand() { result = this.(OperandNode).getOperand() }
+
   /**
    * Gets the non-conversion expression corresponding to this node, if any. If
    * this node strictly (in the sense of `asConvertedExpr`) corresponds to a
@@ -132,6 +136,28 @@ class InstructionNode extends Node, TInstructionNode {
   }
 }
 
+/**
+ * An operand, viewed as a node in a data flow graph.
+ */
+class OperandNode extends Node, TOperandNode {
+  Operand op;
+
+  OperandNode() { this = TOperandNode(op) }
+
+  /** Gets the operand corresponding to this node. */
+  Operand getOperand() { result = op }
+
+  override Declaration getEnclosingCallable() { result = this.getFunction() }
+
+  override Function getFunction() { result = op.getUse().getEnclosingFunction() }
+
+  override Type getType() { result = op.getType() }
+
+  override Location getLocation() { result = op.getLocation() }
+
+  override string toString() { result = this.getOperand().toString() }
+}
+
 /**
  * An expression, viewed as a node in a data flow graph.
  */