Program Optimization Based Pointer Analysis and Live Stack-Heap Analysis

In this paper, we present type systems for flow-sensitive pointer analysis, live stack-heap (variables) analysis, and program optimization. The type system for live stack-heap analysis is an enrichment of that for pointer analysis; the enrichment has the form of a second component being added to types of the latter system. Results of pointer analysis are proved useful via their use in the type system for live stack-heap analysis. The type system for program optimization is also an augmentation of that for live stack-heap analysis, but the augmentation takes the form of a transformation component being added to inference rules of the latter system. The form of program optimization being achieved is that of dead-code elimination. A form of program correction may result indirectly from eliminating faulty code (causing the program to abort) that is dead. Therefore program optimization can result in program correction. Our type systems have the advantage of being compositional and relatively-simply structured. The novelty of our work comes from the fact that our type system for program optimization associates the optimized version of a program with a justification (in the form of a type derivation) for the optimization. This justification is pretty much appreciated in many research areas like certified code (proofcarrying code) which is the motivation of this work.