ABCD

Rastislav Bodík, Rajiv Gupta, Vivek Sarkar
2000 SIGPLAN notices  
v s a r k a r @ u s . i b m . c o m Abstract To guarantee execution, Java and other strongly typed languages require bounds checking of array accesses. Because bounds checks may raise exceptions, they block code motion of instructions with side effects, thus preventing many useful code optimizations, such as partial redundancy elimination or instruction scheduling of memory operations. Furthermore, because it is not expressible at level, the elimination of bounds checks can only be performed at
more » ... run time, after the program is loaded. Using existing powerful bounds-check optimizers at run time is not feasible, however, because they are too heavyweight for the dynamic compilation setting. ABCD is a light-weight algorithm for elimination of &ray Checks on Demand. Its design emphasizes simplicity and efficiency. In essence, ABCD works by adding a few edges to the SSA value graph and performing a simple traversal of the graph. Despite its simplicity, ABCD is surprisingly powerful. On our benchmarks, ABCD removes on average 45% of dynamic bound check instructions, sometimes achieving near-ideal optimization. The efficiency of ABCD stems from two factors. First, ABCD works on a representation. As a result, it requires on average fewer than 10 simple analysis steps per bounds check. Second, ABCD is demand-driven. It can be applied to a set of frequently executed (hot) bounds checks, which makes it suitable for the dynamic-compilation setting, in which compile-time cost is constrained but hot statements are known.
doi:10.1145/358438.349342 fatcat:2l7hliy7iffxdkqw5m42ia6ff4