Lifetime analysis for procedure parameters

Abstract

Procedural abstraction is an important concept for functional and imperative programming as well. Compilers should implement procedures and calls as efficient as possible. This paper addresses techniques for both memory and runtime improvements of procedure calls. Usual implementations allocate storage for local objects of procedures (i.e. parameters, result and local variables) either in activation records on a runtime stack in the case of recursive procedures or in a global storage area otherwise. We show that objects of recursive procedures can also be allocated globally, if certain conditions on their lifetime are met. We present a method for systematic lifetime analysis based on a context-free grammar which describes the calling structure of the program. It is introduced for a simple functional language and then extended to cover further commom language properties. Furthermore it is shown that the method can nicely be combined with context dependent improvements of the compilation of calling sequences, e.g. for tail recursive calls.