[Interpreter] Ensure that implicit return undefined is generated.

src/interpreter/bytecode-array-builder.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_
 #define V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_
 
 #include <vector>
 
 #include "src/ast.h"
@@ skipping 17 matching lines @@
   Handle<BytecodeArray> ToBytecodeArray();
 
   // Set number of parameters expected by function.
   void set_parameter_count(int number_of_params);
   int parameter_count() const;
 
   // Set number of locals required for bytecode array.
   void set_locals_count(int number_of_locals);
   int locals_count() const;
 
+  // Returns true if the bytecode has an explicit return at the end.
+  bool HasExplicitReturn();
+
   Register Parameter(int parameter_index);
 
   // Constant loads to accumulator.
   BytecodeArrayBuilder& LoadLiteral(v8::internal::Smi* value);
   BytecodeArrayBuilder& LoadLiteral(Handle<Object> object);
   BytecodeArrayBuilder& LoadUndefined();
   BytecodeArrayBuilder& LoadNull();
   BytecodeArrayBuilder& LoadTheHole();
   BytecodeArrayBuilder& LoadTrue();
   BytecodeArrayBuilder& LoadFalse();
@@ skipping 66 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(TemporaryRegisterScope);
 };
 
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_