Combining Global Code and Data Compaction

Abstract

Computers are increasingly being incorporated in devices with a limited amount of available memory. As a result research is increasingly focusing on the automated reduction of program size. Existing literature focuses on either data or code compaction or on highly language dependent techniques. This paper shows how combined code and data compaction can be achieved using a link-time code compaction system that reasons about the use of both code and data addresses. The analyses proposed rely only on fundamental properties of linked code and are therefore generally applicable. The combined code and data compaction is implemented in SQUEEZE, a link-time program compaction system, and evaluated on SPEC2000, MediaBench and C++ programs, resulting in total binary program size reductions of 23.6%-46.6%. This compaction involves no speed trade-off, as the compacted programs are on average about 8% faster.