Some question about stoke search a result

[Angerla]

Hi, I have been learning stoke recently, but I have meed some problem:
1）I wonder how Stoke works on searching a result? I output some code in search.cc to make it print each structure state.current' s CFG. I find that there only has one block (without entry and exit block), is there have any problem in my process?
2) I wonder how to set parameters in file synthesize.conf when synthesizing a function, especially the parameters "--def_in" and "--live_out" or any other important parameters' setting rule.
3)I wonder to know whether stoke only optimized for instructions related to the "def_in" register in target.s?
Hope your help!Thanks!