Await it!

runtime/vm/ast_transformer.h

 // 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.
 
 #ifndef VM_AST_TRANSFORMER_H_
 #define VM_AST_TRANSFORMER_H_
 
 #include "platform/assert.h"
 #include "vm/ast.h"
 
@@ skipping 28 matching lines @@
 //
 class AwaitTransformer : public AstNodeVisitor {
  public:
   AwaitTransformer(SequenceNode* preamble,
                    const Library& library,
                    ParsedFunction* const parsed_function)
     : preamble_(preamble),
       temp_cnt_(0),
       library_(library),
       parsed_function_(parsed_function),
-      isolate_(Isolate::Current()) {}
+      isolate_(Isolate::Current()) {
+    // We later on save the continuation context and modify the jump counter
+    // from within the preamble context (in the FlowGraphBuilder). Look up the
+    // needed variables to get their corresponding aliases.
+    preamble->scope()->LookupVariable(Symbols::AwaitContextVar(), false);
+    preamble->scope()->LookupVariable(Symbols::AwaitJumpVar(), false);
+  }
 
 #define DECLARE_VISIT(BaseName)                                                \
   virtual void Visit##BaseName##Node(BaseName##Node* node);
 
   FOR_EACH_NODE(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
   AstNode* Transform(AstNode* expr);
 
  private:
@@ skipping 15 matching lines @@
   ParsedFunction* const parsed_function_;
 
   Isolate* isolate_;
 
   DISALLOW_COPY_AND_ASSIGN(AwaitTransformer);
 };
 
 }  // namespace dart
 
 #endif  // VM_AST_TRANSFORMER_H_