Some reverse-execution and omniscient debuggers are in commercial use, but market penetration remains limited and many developers and educators remain unaware of the capabilities available. This technical briefing will introduce participants to state-of-the-art debugging techniques, with hands-on usage of rr and Pernosco to analyze some realistic bugs in real applications. We will discuss the strengths and weaknesses of the tools.

In 2001 Robert graduated with a PhD in computer science from Carnegie Mellon University, supervised by Daniel Jackson and Jeannette Wing, on polymorphic type inference for context-sensitive alias analysis for Java code.

From 2001 to 2004 he worked at IBM Research on dynamic program analysis tools.

From 2000 he moonlighted as a volunteer working on the Mozilla open source project, which became Firefox. In 2005 he moved back to New Zealand to work full-time on Firefox’s browser engine; Mozilla awarded him the title of Distinguished Engineer. In his last few years at Mozilla he led the development of “rr”, a practical record-and-replay debugger supporting reverse execution, used by many developers inside and outside Mozilla to the present day. He continues as an rr maintainer to this day.

In 2016 he left Mozilla to co-found Pernosco, a startup working on cloud-based, omniscient debugging leveraging rr.

In 2022 he joined Google Research to work on various projects mostly unrelated to debugging.

He lives in New Zealand and enjoys hiking, board games and lay preaching.