Surprisingly backtrace apparently uses self-modifying code in production for feature flags: https://engineering.backtrace.io/2021-12-19-bounded-dynamicism-with

Surprisingly backtrace apparently uses self-modifying code in production for feature flags: https://engineering.backtrace.io/2021-12-19-bounded-dynamicism-with-cross-modifying-code/ https://engineering.backtrace.io/2021-12-19-bounded-dynamici... This is basically to make it zero cost (as far as I remember) Google uses a similar system of feature flags, but as far as I know there's no self-modifying code. I guess Backtrace wants to put the flags in tight inner loops. dtrace and I believe systemtap patch the executable at runtime, for similar performance reasons. But those are kernel features and not user applications.