Introduce await

runtime/vm/ast_transformer.h

Index: runtime/vm/ast_transformer.h
diff --git a/runtime/vm/ast_transformer.h b/runtime/vm/ast_transformer.h
new file mode 100644
index 0000000000000000000000000000000000000000..f4e8ce55a74d7d63a4238e72af9c2404e96efe85
--- /dev/null
+++ b/runtime/vm/ast_transformer.h
@@ -0,0 +1,54 @@
+// 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"
+
+namespace dart {
+
+class ParsedFunction;
+
+class AwaitTransformer : public AstNodeVisitor {
+ public:
+  explicit AwaitTransformer(SequenceNode* preamble,
+                            const Library& library,
+                            ParsedFunction* const parsed_function)
+    : preamble_(preamble),
+      temp_cnt_(0),
+      library_(library),
+      parsed_function_(parsed_function) {}
+
+#define DECLARE_VISIT(BaseName)                                                \
+  virtual void Visit##BaseName##Node(BaseName##Node* node);
+
+  FOR_EACH_NODE(DECLARE_VISIT)
+#undef DECLARE_VISIT
+
+  void Transform(AstNode* expr);
+  AstNode* Result() const { return result_; }
+
+ private:
+  LocalVariable* EnsureCurrentTempVar();
+  void NextTempVar() { temp_cnt_++; }
+  LocalVariable* AddToPreambleNewTempVar(AstNode* node);
+  ArgumentListNode* TransformArguments(ArgumentListNode* node);
+  AstNode* LazyTransform(const Token::Kind kind,
+                         AstNode* new_left,
+                         AstNode* right);
+
+  SequenceNode* preamble_;
+  intptr_t temp_cnt_;
+  AstNode* result_;
+  const Library& library_;
+  ParsedFunction* const parsed_function_;
+
+  DISALLOW_COPY_AND_ASSIGN(AwaitTransformer);
+};
+
+}  // namespace dart
+
+#endif  // VM_AST_TRANSFORMER_H_