On Enabling the WAM with Region Support

摘要

Region-based memory management is an attractive alternative to garbage collection. It relies on a compile-time analysis to annotate the program with explicit allocation and deallocation instructions, where lifetimes of memory objects are grouped together in regions. This paper investigates how to adapt the runtime part of region-based memory management to the WAM setting. We present additions to the memory architecture and instruction set of the WAM that are necessary to implement regions. We extend an optimized WAM-based Prolog implementation with a region-based memory manager which supports backtracking with instant reclamation, and cuts. The performance of region-based execution is compared with that of the baseline garbage-collected implementation on several benchmark programs. A region-enabled WAM performs competitively and often results in time and/or space improvements.