The invention provides an improved method and method for locating the origin of runtime defect in software programs. A differential debugging technique may be implemented to locate the diversion point where two programs start to behave differently. In one approach, the method generally involves running the two programs and generating respective control flow diagrams via a static code analyzer or the like. Tracer and supervisor modules may be used to replace addresses in registers with symbols and/or position-independent offsets, and to locate where differences in the register states occur.