Minimizing row displacement dispatch tables

  • Authors:
  • Karel Driesen;Urs Hölzle

  • Affiliations:
  • Department of Computer Science, University of California, Santa Barbara, CA;Department of Computer Science, University of California, Santa Barbara, CA

  • Venue:
  • Proceedings of the tenth annual conference on Object-oriented programming systems, languages, and applications
  • Year:
  • 1995

Quantified Score

Hi-index 0.00

Visualization

Abstract

Row displacement dispatch tables implement message dispatching for dynamically-typed languages with a run time overhead of one memory indirection plus an equality test. The technique is similar to virtual function table lookup, which is, however, restricted to statically typed languages like C++. We show how to reduce the space requirements of dispatch tables to approximately the same size as virtual function tables. The scheme is then generalized for multiple inheritance. Experiments on a number of class libraries from five different languages demonstrate that the technique is effective for a broad range of programs. Finally, we discuss optimizations of the row displacement algorithm that allow dispatch table construction of these large samples to take place in a few seconds.