An Optimising Delivery System for Object-Oriented Software

An open-ended and flexible object-oriented language ideally requires its compiler to optimise code at the time of building complete application systems. Optimum code can be judged in terms of its size, which should be compact, and speed of execution, which should be fast. In addition, the turn-around time for recompilation should be as short as possible. We have developed four strategies, based on graph analysis, which allow these objectives to be attained in a more consistent manner than with current compilers. Our development system traces inter-class dependencies automatically to minimise the number of passes over source files at compilation. Our optimiser then performs three tasks: firstly it transforms the system of classes ported into the target application by collapsing inheritance relationships; secondly it determines whether methods should be statically or dynamically bound for that application; and thirdly it removes the unnecessary levels of nesting in call graphs which arise from strict encapsulation, by detecting safe cases for inlining which are also guaranteed to reduce code size. Our findings are being incorporated in BRUNEL, a new object-oriented language an