Garbage collection and other optimizations

[摘要] Existing techniques for garbage collection and machine code optimizations can interfere with each other. The inability to fully optimize code in a garbage-collected system is a hidden cost of garbage collection. One solution to this problem is proposed; an inexpensive protocol that permits most optimizations and garbage collection to coexist. A second approach to this problem and a separate problem in its own right is to reduce the need for garbage collection. This requires analysis of storage lifetime. Inferring storage lifetime is difficult in a language with nested and recursive data structures, but it is precisely these languages in which garbage collection is most useful. An improved analysis for ;;storage containment;; is described. Containment information can be represented in a directed graph. The derivation of this graph falls into a monotone data-flow analysis framework; in addition, the derivation has the Church-Rosser property. The graphs produced in the analysis of a value-assignment language have the property that they can be replaced with a single graph without losing any information. These properties also assist in the generation of graphs for side-effect languages. A different approach to avoiding obtaining memory from the garbage collector is also proposed. Existing techniques are either not general or run the risk of consuming all of a bounded memory. A general, low overhead technique that does not consume excessive amounts of memory is described.

[发布机构] Rice University