C++: Cleanup now that we're back to an abstract class.

Author: MathiasVP

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

@@ -1,14 +1,14 @@
 /**
- * This file contains a module that implements the _debug_ version of
+ * This file contains the class that implements the _debug_ version of
  * `toString` for `Instruction` and `Operand` dataflow nodes.
  */
 
 private import semmle.code.cpp.ir.IR
 private import codeql.util.Unit
-private import Node0ToStringSig
+private import Node0ToString
 private import DataFlowUtil
 
-class DebugNode0ToString extends Node0ToString {
+private class DebugNode0ToString extends Node0ToString {
   override string instructionToString(Instruction i) { result = i.getDumpString() }
 
   override string operandToString(Operand op) {

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/Node0ToString.qll

@@ -1,9 +1,53 @@
 /**
- * This file imports the module that is used to construct the strings used by `Node.ToString`.
+ * This file imports the class that is used to construct the strings used by
+ * `Node.ToString`.
  *
- * Normally, this file should just import `NormalNode0ToString` to compute the efficient `toString`, but for debugging purposes
- * one can import `DebugPrinting.qll` to better correlate the dataflow nodes with their underlying instructions and operands.
+ * Normally, this file should just import `NormalNode0ToString` to compute the
+ * efficient `toString`, but for debugging purposes one can import
+ * `DebugPrinting.qll` to better correlate the dataflow nodes with their
+ * underlying instructions and operands.
  */
 
-import Node0ToStringSig
-import NormalNode0ToString
+private import semmle.code.cpp.ir.IR
+private import codeql.util.Unit
+private import DataFlowUtil
+import NormalNode0ToString // Change this import to control which version should be used.
+
+/** An abstract class to control the behavior of `Node.toString`. */
+abstract class Node0ToString extends Unit {
+  /**
+   * Gets the string that should be used by `OperandNode.toString` to print the
+   * dataflow node whose underlying operand is `op.`
+   */
+  abstract string operandToString(Operand op);
+
+  /**
+   * Gets the string that should be used by `InstructionNode.toString` to print
+   * the dataflow node whose underlying instruction is `instr`.
+   */
+  abstract string instructionToString(Instruction i);
+
+  /**
+   * Gets the string representation of the `Expr` associated with `n`, if any.
+   */
+  abstract string toExprString(Node n);
+}
+
+/**
+ * Gets the string that should be used by `OperandNode.toString` to print the
+ * dataflow node whose underlying operand is `op.`
+ */
+string operandToString(Operand op) { result = any(Node0ToString s).operandToString(op) }
+
+/**
+ * Gets the string that should be used by `InstructionNode.toString` to print
+ * the dataflow node whose underlying instruction is `instr`.
+ */
+string instructionToString(Instruction instr) {
+  result = any(Node0ToString s).instructionToString(instr)
+}
+
+/**
+ * Gets the string representation of the `Expr` associated with `n`, if any.
+ */
+string toExprString(Node n) { result = any(Node0ToString s).toExprString(n) }

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/Node0ToStringSig.qll

@@ -1,15 +1,15 @@
 /**
- * This file contains module that implements the non-debug version of
+ * This file contains the class that implements the non-debug version of
  * `toString` for `Instruction` and `Operand` dataflow nodes.
  */
 
 private import semmle.code.cpp.ir.IR
 private import codeql.util.Unit
-private import Node0ToStringSig
+private import Node0ToString
 private import DataFlowUtil
 private import DataFlowPrivate
 
-class NormalNode0ToStringImpl extends Node0ToString {
+private class NormalNode0ToString extends Node0ToString {
   override string instructionToString(Instruction i) {
     if i.(InitializeParameterInstruction).getIRVariable() instanceof IRThisVariable
     then result = "this"