A data structure of a run-time object having a hash value field. The data structure allows an object allocation site to be traced from the run-time object, the object allocation site being a site in a program allocating the run-time object. A method for allowing an object allocation site to be traced from a run-time object includes embedding a value corresponding to the object allocation site in the program. A hash-value field includes the embedded value and the object identifier, and the tracing is performed by identifying the object allocation site that corresponds to the embedded value. A computer system for tracing an object allocation site includes a memory that stores the run-time object; an acquirer that acquires the value from a hash value field; and an identification unit that identifies the object allocation site that corresponds to the acquired value.