Often when making changes in the compiler it can be useful to have flags that are set for particular compiles as a way to narrow down the cause of performance differences. It's also useful for experimentation since you can special behaviour. This similar to the print command in the CompilerOracle but generalized to arbitrary strings. It can be used to wrap around existing compilation flags or to make up new flags as needed during development.
Added a new syntax in the oracle like so:
option java/lang/String hashCode foo
Then in the VM if you have a methodOop or ciMethod that refers to String.hashCode you can say method->has_option("foo") and it will return true