Support OSR in for-in loops.

src/hydrogen.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 381 matching lines @@
   int push_count() const { return push_count_; }
 
   int ast_id() const { return ast_id_; }
   void set_ast_id(int id) { ast_id_ = id; }
 
   int length() const { return values_.length(); }
   bool is_special_index(int i) const {
     return i >= parameter_count() && i < parameter_count() + specials_count();
   }
 
+  int first_expression_index() const {
+    return parameter_count() + specials_count() + local_count();
+  }
+
   void Bind(Variable* variable, HValue* value) {
     Bind(IndexFor(variable), value);
   }
 
   void Bind(int index, HValue* value);
 
   void BindContext(HValue* value) {
     Bind(parameter_count(), value);
   }
 
@@ skipping 897 matching lines @@
   const char* filename_;
   HeapStringAllocator string_allocator_;
   StringStream trace_;
   int indent_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_H_