OPTVIEW - A NEW APPROACH FOR EXAMINING OPTIMIZED CODE

The task of mapping between source programs and machine code, once the code has been optimized and transformed by a compiler is often diffic ult. Yet there are many instances! such as debugging optimized code or attributing performance analysis data to source lines, when it is use ful or necessary to understand at the source level what is occurring i n the binary. The standard approach has been for tools to attempt to m ap directly from the optimized binary to the original source. Such map pings are often fragile, and sometimes inaccurate or misleading. We su ggest an alternative approach. Rather than mapping directly between th e original source and the binary, we create a modified version of the source program, still recognizable, but updated to reflect some of the effects of optimizations, thus facilitating mapping from the binary. We have implemented a tool, Optview, to demonstrate and test these ide as.