Instruction-level reverse execution for debugging

Abstract

The ability to execute a program in reverse is advantageous for shortening debug time. This paper presents a reverse execution methodology at the assembly instruction-level with low memory and time overheads. The core idea of this approach is to generate a reverse program able to undo, in almost all cases, normal forward execution of an assembly instruction in the program being debugged. The methodology has been implemented on a PowerPC processor in a custom made debugger. Compared to previous work -- all of which use a variety of state saving techniques -- the experimental results show 2.5X to 400X memory overhead reduction for the tested benchmarks. Furthermore, the results with the same benchmarks show an average of 4.1X to 5.7X time overhead reduction.