C++: Support the spaceship operator in the IR

cpp/ql/lib/semmle/code/cpp/ir/implementation/Opcode.qll

@@ -42,6 +42,7 @@ private newtype TOpcode =
   TCompareGT() or
   TCompareLE() or
   TCompareGE() or
+  TSpaceship() or
   TPointerAdd() or
   TPointerSub() or
   TPointerDiff() or
@@ -765,6 +766,15 @@ module Opcode {
     final override string toString() { result = "CompareGE" }
   }
 
+  /**
+   * The `Opcode` for a `SpaceshipInstruction`.
+   *
+   * See the `SpaceshipInstruction` documentation for more details.
+   */
+  class Spaceship extends BinaryOpcode, TSpaceship {
+    final override string toString() { result = "Spaceship" }
+  }
+
   /**
    * The `Opcode` for a `PointerAddInstruction`.
    *

cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll

@@ -1604,6 +1604,13 @@ class CompareGEInstruction extends RelationalInstruction {
   override predicate isStrict() { none() }
 }
 
+/**
+ * An instruction that represents a three-way comparison operator.
+ */
+class CompareThreeWayInstruction extends BinaryInstruction {
+  CompareThreeWayInstruction() { this.getOpcode() instanceof Opcode::Spaceship }
+}
+
 /**
  * An instruction that branches to one of multiple successor instructions based on the value of an
  * integer operand.

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/Instruction.qll

@@ -1604,6 +1604,13 @@ class CompareGEInstruction extends RelationalInstruction {
   override predicate isStrict() { none() }
 }
 
+/**
+ * An instruction that represents a three-way comparison operator.
+ */
+class CompareThreeWayInstruction extends BinaryInstruction {
+  CompareThreeWayInstruction() { this.getOpcode() instanceof Opcode::Spaceship }
+}
+
 /**
  * An instruction that branches to one of multiple successor instructions based on the value of an
  * integer operand.

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/internal/TranslatedExpr.qll

@@ -1808,6 +1808,11 @@ private Opcode comparisonOpcode(ComparisonOperation expr) {
   expr instanceof GEExpr and result instanceof Opcode::CompareGE
 }
 
+private Opcode spaceShipOpcode(SpaceshipExpr expr) {
+  exists(expr) and
+  result instanceof Opcode::Spaceship
+}
+
 /**
  * IR translation of a simple binary operation.
  */
@@ -1867,7 +1872,8 @@ class TranslatedBinaryOperation extends TranslatedSingleInstructionExpr {
   override Opcode getOpcode() {
     result = binaryArithmeticOpcode(expr) or
     result = binaryBitwiseOpcode(expr) or
-    result = comparisonOpcode(expr)
+    result = comparisonOpcode(expr) or
+    result = spaceShipOpcode(expr)
   }
 
   override Type getExprType() {

cpp/ql/lib/semmle/code/cpp/ir/implementation/unaliased_ssa/Instruction.qll

@@ -1604,6 +1604,13 @@ class CompareGEInstruction extends RelationalInstruction {
   override predicate isStrict() { none() }
 }
 
+/**
+ * An instruction that represents a three-way comparison operator.
+ */
+class CompareThreeWayInstruction extends BinaryInstruction {
+  CompareThreeWayInstruction() { this.getOpcode() instanceof Opcode::Spaceship }
+}
+
 /**
  * An instruction that branches to one of multiple successor instructions based on the value of an
  * integer operand.