GC-safe interprocedural unboxing

Abstract

Modern approaches to garbage collection (GC) require information about which variables and fields contain GC-managed pointers. Interprocedural flow analysis can be used to eliminate otherwise unnecessary heap allocated objects (unboxing), but must maintain the necessary GC information. We define a core language which models compiler correctness with respect to the GC, and develop a correctness specification for interprocedural unboxing optimizations. We prove that any optimization which satisfies our specification will preserve GC safety properties and program semantics, and give a practical unboxing algorithm satisfying this specification. © 2012 Springer-Verlag.