Unspeculation
Department of Computer Science
University of Arizona
Tucson, AZ 85721, U.S.A.
Modern architectures, such as the Intel Itanium, support speculation, a hardware mechanism that allows the early execution of expensive operations---possibly even before it is known whether the results of the operation are needed. While such speculative execution can improve execution performance considerably, it requires a significant amount of complex support code to deal with and recover from speculation failures. This greatly complicates the tasks of understanding and re-engineering speculative code. This paper describes a technique for removing speculative instructions from optimized binary programs in a way that is guaranteed to preserve program semantics, thereby making the resulting "unspeculated" programs easier to understand and more amenable to re-engineering using traditional reverse engineering techniques.