dart2js cps: Support sync* and yield.

pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library tree_ir_builder;
 
 import '../diagnostics/invariant.dart' show
     InternalErrorFunction;
 import '../diagnostics/spannable.dart' show
     CURRENT_ELEMENT_SPANNABLE;
@@ skipping 418 matching lines @@
     }
   }
 
   NodeCallback visitGetLazyStatic(cps_ir.GetLazyStatic node) {
     // In the tree IR, GetStatic handles lazy fields because we do not need
     // as fine-grained control over side effects.
     GetStatic value = new GetStatic(node.element, node.sourceInformation);
     return makeCallExpression(node, value);
   }
 
+  @override
+  NodeCallback visitYield(cps_ir.Yield node) {
+    return (Statement next) {
+      return new Yield(getVariableUse(node.input), node.hasStar, next);
+    };
+  }
+
+  @override
+  NodeCallback visitAwait(cps_ir.Await node) {
+    Expression value = new Await(getVariableUse(node.input));
+    return makeCallExpression(node, value);
+  }
+
 
   /************************** TAIL EXPRESSIONS  **************************/
   //
   // Visit methods for tail expressions must return a statement directly
   // (not a function like interior and call expressions).
 
   Statement visitThrow(cps_ir.Throw node) {
     Expression value = getVariableUse(node.value);
     return new Throw(value);
   }
@@ skipping 214 matching lines @@
                         getVariableUse(node.index));
   }
 
   Expression visitSetIndex(cps_ir.SetIndex node) {
     return new SetIndex(getVariableUse(node.object),
                         getVariableUse(node.index),
                         getVariableUse(node.value));
   }
 
   @override
-  NodeCallback visitAwait(cps_ir.Await node) {
-    Expression value = new Await(getVariableUse(node.input));
-    return makeCallExpression(node, value);
-  }
-
-  @override
   Expression visitRefinement(cps_ir.Refinement node) {
     throw 'Unexpected Refinement node in tree builder';
   }
 
   /********** UNUSED VISIT METHODS *************/
 
   unexpectedNode(cps_ir.Node node) {
     internalError(CURRENT_ELEMENT_SPANNABLE, 'Unexpected IR node: $node');
   }
 
   visitFunctionDefinition(cps_ir.FunctionDefinition node) {
     unexpectedNode(node);
   }
   visitParameter(cps_ir.Parameter node) => unexpectedNode(node);
   visitContinuation(cps_ir.Continuation node) => unexpectedNode(node);
   visitMutableVariable(cps_ir.MutableVariable node) => unexpectedNode(node);
 }