cps-ir: Support foreign code.

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 164663372e22cb8250b1c25be82a45353fa5b459..f81d4c1220fbdfae8629f2fdf4ae16840816d401 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart
@@ -10,6 +10,13 @@ import '../elements/elements.dart';
 import '../io/source_information.dart' show SourceInformation;
 import '../universe/universe.dart' show Selector, SelectorKind;
 
+// These imports are only used for the JavaScript specific nodes.  If we want to
+// support more than one native backend, we should probably create better
+// abstractions for native code and its type and effect system.
+import '../js/js.dart' as js show Template;
+import '../native/native.dart' as native show NativeBehavior;
+import '../types/types.dart' as types show TypeMask;
+
 abstract class Node {
   /// A pointer to the parent node. Is null until set by optimization passes.
   Node parent;
@@ -722,6 +729,23 @@ class CreateInvocationMirror extends Primitive {
   accept(Visitor visitor) => visitor.visitCreateInvocationMirror(this);
 }
 
+class ForeignCode extends Expression {
+  final js.Template codeTemplate;
+
+  final types.TypeMask type;
+  final List<Reference<Primitive>> arguments;
+  final Reference<Continuation> continuation;
+  final native.NativeBehavior nativeBehavior;
+  final FunctionElement dependency;
+
+  ForeignCode(this.codeTemplate, this.type, List<Primitive> arguments,
+      Continuation continuation, this.nativeBehavior, {this.dependency})
+      : arguments = _referenceList(arguments),
+        continuation = new Reference<Continuation>(continuation);
+
+  accept(Visitor visitor) => visitor.visitForeignCode(this);
+}
+
 class Constant extends Primitive {
   final ConstantExpression expression;
   final values.ConstantValue value;
@@ -955,6 +979,9 @@ abstract class Visitor<T> {
 
   // Conditions.
   T visitIsTrue(IsTrue node);
+
+  // Support for literal foreign code.
+  T visitForeignCode(ForeignCode node);
 }
 
 /// Recursively visits the entire CPS term, and calls abstract `process*`
@@ -1234,6 +1261,13 @@ class RecursiveVisitor implements Visitor {
     node.arguments.forEach(processReference);
   }
 
+  processForeignCode(ForeignCode node) {}
+  visitForeignCode(ForeignCode node) {
+    processForeignCode(node);
+    processReference(node.continuation);
+    node.arguments.forEach(processReference);
+  }
+
   processUnreachable(Unreachable node) {}
   visitUnreachable(Unreachable node) {
     processUnreachable(node);