How to obtain the compiler frontend result?

I’d like to process some classes that reside within a certain package.

My idea was to use the compiler frontend to obtain the symbols, classes and types from the package… but I am lost on which arguments to do so or finding a guide that would point me how to run the compiler frontend (no JVM bytecode / Native code/ JS code generation) and let me know the fully qualified types, classes, functions and properties from the package…

WITHOUT compiling a .jar file and then using a class loader to inspect my way through the jar to perform such analysis… Is that even possible?

Where can I find the documentation of the compiler that would point me to the right direction?

Thanks, Miquel