Abstracting access patterns of dynamic memory using regular expressions

Unless the speed gap between CPU and memory disappears, efficient memory usage remains a decisive factor for performance. To optimize data usage of programs in the presence of the memory hierarchy, we are particularly interested in two compiler techniques: pool allocation and field layout restructuring. Since foreseeing runtime behaviors of programs at compile time is difficult, most of the previous work relied on profiling. On the contrary, our goal is to develop a fully automatic compiler that statically transforms input codes to use memory efficiently. Noticing that regular expressions, which denote repetition explicitly, are sufficient for memory access patterns, we describe how to extract memory access patterns as regular expressions in detail. Based on static patterns presented in regular expressions, we apply pool allocation to repeatedly accessed structures and exploit field layout restructuring according to field affinity relations of chosen structures. To make a scalable framework, we devise and apply new abstraction techniques, which build and interpret access patterns for the whole programs in a bottom-up fashion. We implement our analyses and transformations with the CIL compiler. To verify the effect and scalability of our scheme, we examine 17 benchmarks including 2 SPECINT 2000 benchmarks whose source lines of code are larger than 10,000. Our experiments demonstrate that the static layout transformations for dynamic memory can reduce L1D cache misses by 16% and execution times by 14% on average.