please help understanding what's the function and diffrence between hotspot compiler c1 and c2 ？

[恶灵骑士]

what's the function and diffrence between hotspot compiler c1 and c2 ？


about c1，
i have found something about ‘voaltile’ and  
methods  LIRGenerator::do_StoreField(StoreField* x)  and  LIRGenerator::do_LoadField(LoadField* x) in   ‘share/vm/c1/c1_LIRGenerator.cpp‘，


when operating a  variable with a volatile qualifier，will it finally invoke do_StoreField or do_LoadField method？
if true， then method do_LoadField or do_StoreField  by  which method？