dart2js cps_ir: Use interceptors for is-checks (version 2)

pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart

Index: pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart
diff --git a/pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart b/pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart
index 19b0543c179877ab2a4d7ba2c7061d8822b6f116..0c28fa4cc9a53283df59ac6913a62231fc5a9492 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart
@@ -589,24 +589,30 @@ class TypeTest extends Primitive {
   Reference<Primitive> value;
   final DartType dartType;
 
-  /// If [type] is an [InterfaceType], this holds the internal representation of
-  /// the type arguments to [type]. Since these may reference type variables
-  /// from the enclosing class, they are not constant.
+  /// If [dartType] is an [InterfaceType], this holds the internal
+  /// representation of the type arguments to [dartType]. Since these may
+  /// reference type variables from the enclosing class, they are not constant.
   ///
-  /// If [type] is a [TypeVariableType], this is a singleton list with
-  /// the internal representation of the type held in that type variable.
+  /// If [dartType] is a [TypeVariableType], this is a singleton list with the
+  /// internal representation of the type held in that type variable.
   ///
-  /// If [type] is a [FunctionType], this is a singleton list with the
+  /// If [dartType] is a [FunctionType], this is a singleton list with the
   /// internal representation of that type,
   ///
   /// Otherwise the list is empty.
   final List<Reference<Primitive>> typeArguments;
 
+  /// The Interceptor for [value].  May be `null` if the test can be done
+  /// without an interceptor.  May be the same as [value] after self-interceptor
+  /// optimization.
+  // TODO(24523): Remove this field.
+  Reference<Primitive> interceptor;
+
   TypeTest(Primitive value,
            this.dartType,
            List<Primitive> typeArguments)
-  : this.value = new Reference<Primitive>(value),
-    this.typeArguments = _referenceList(typeArguments);
+      : this.value = new Reference<Primitive>(value),
+        this.typeArguments = _referenceList(typeArguments);
 
   accept(Visitor visitor) => visitor.visitTypeTest(this);
 
@@ -614,6 +620,22 @@ class TypeTest extends Primitive {
   bool get isSafeForReordering => true;
 }
 
+/// An "is" type test for a raw type, performed by testing a flag property.
+///
+/// Returns `true` if [interceptor] is for [dartType].
+class TypeTestViaFlag extends Primitive {
+  Reference<Primitive> interceptor;
+  final DartType dartType;
+
+  TypeTestViaFlag(Primitive interceptor, this.dartType)
+      : this.interceptor = new Reference<Primitive>(interceptor);
+
+  accept(Visitor visitor) => visitor.visitTypeTestViaFlag(this);
+
+  bool get isSafeForElimination => true;
+  bool get isSafeForReordering => true;
+}
+
 /// An "as" type cast.
 ///
 /// If [value] is `null` or is an instance of [type], [continuation] is invoked
@@ -1371,6 +1393,7 @@ abstract class Visitor<T> {
   T visitTypeExpression(TypeExpression node);
   T visitCreateInvocationMirror(CreateInvocationMirror node);
   T visitTypeTest(TypeTest node);
+  T visitTypeTestViaFlag(TypeTestViaFlag node);
   T visitApplyBuiltinOperator(ApplyBuiltinOperator node);
   T visitApplyBuiltinMethod(ApplyBuiltinMethod node);
   T visitGetLength(GetLength node);
@@ -1496,9 +1519,16 @@ class LeafVisitor implements Visitor {
   visitTypeTest(TypeTest node) {
     processTypeTest(node);
     processReference(node.value);
+    if (node.interceptor != null) processReference(node.interceptor);
     node.typeArguments.forEach(processReference);
   }
 
+  processTypeTestViaFlag(TypeTestViaFlag node) {}
+  visitTypeTestViaFlag(TypeTestViaFlag node) {
+    processTypeTestViaFlag(node);
+    processReference(node.interceptor);
+  }
+
   processSetMutable(SetMutable node) {}
   visitSetMutable(SetMutable node) {
     processSetMutable(node);