Await it!

runtime/vm/ast.h

Index: runtime/vm/ast.h
diff --git a/runtime/vm/ast.h b/runtime/vm/ast.h
index 7c1279b4fa58df4e01c3b4a5025664d3e6afa18f..62eb4bbf55c0f842dabe7a052bc8428a9a9a2fd3 100644
--- a/runtime/vm/ast.h
+++ b/runtime/vm/ast.h
@@ -17,6 +17,7 @@ namespace dart {
 
 #define FOR_EACH_NODE(V)                                                       \
   V(Await)                                                                     \
+  V(AwaitMarker)                                                               \
   V(Return)                                                                    \
   V(Literal)                                                                   \
   V(Type)                                                                      \
@@ -168,6 +169,33 @@ class AwaitNode : public AstNode {
 };
 
 
+class AwaitMarkerNode : public AstNode {
+ public:
+  enum Type {
+    kNewContinuationState,
+    kTargetForContinuation,
+  };
+
+  explicit AwaitMarkerNode(Type type)
+    : AstNode(Scanner::kNoSourcePos), type_(type) { }
+
+  void VisitChildren(AstNodeVisitor* visitor) const { }
+
+  Type type() const { return type_; }
+
+  LocalScope* scope() const { return scope_; }
+  void set_scope(LocalScope* scope) { scope_ = scope; }
+
+  DECLARE_COMMON_NODE_FUNCTIONS(AwaitMarkerNode);
+
+ private:
+  Type type_;
+  LocalScope* scope_;
+
+  DISALLOW_COPY_AND_ASSIGN(AwaitMarkerNode);
+};
+
+
 class SequenceNode : public AstNode {
  public:
   SequenceNode(intptr_t token_pos, LocalScope* scope)
@@ -537,8 +565,6 @@ class PrimaryNode : public AstNode {
 };
 
 
-// TODO(mlippautz): Implement return nodes that are used to return from a
-// continuation.
 class ReturnNode : public AstNode {
  public:
   // Return from a void function returns the null object.
@@ -580,6 +606,9 @@ class ReturnNode : public AstNode {
 
   // Returns false if the return node is used to return from a continuation.
   bool is_regular_return() const { return is_regular_return_; }
+  void set_is_regular_return(bool is_regular_return) {
+    is_regular_return_ = is_regular_return;
+  }
 
   DECLARE_COMMON_NODE_FUNCTIONS(ReturnNode);