An automatic object inlining optimization and its evaluation

Abstract

Automatic object inlining [19, 20] transforms heap data structures by fusing parent and child objects together. It can improve runtime by reducing object allocation and pointer dereference costs. We report continuing work studying object inlining optimizations. In particular, we present a new semantic derivation of the correctness conditions for object inlining, and program analysis which extends our previous work. And we present an object inlining transformation, focusing on a new algorithm which optimizes class field layout to minimize code expansion. Finally, we detail a fuller evaluation on eleven programs and libraries (including Xpdf, the 25,000 line Portable Document Format (PDF) le browser) that utilizes hardware measures of impact on the memory system. We show that our analysis scales effectively to large programs, nding many inlinable elds (45 in xpdf) at acceptable cost, and we show that, on some programs, it finds nearly all fields for which object inlining is correct, and a...