XCode Optimization Level has to be None [-O0] for successful build

Our game was launched couple months ago without any XCode building problem, last month we updated it with new feature such ARKit and updated some plugins...

Even since than we have to set the Optimization Level to -O0 in XCode 9, otherwise the compile takes forever until it eats up all disk space and fails. (I have 10+GB empty space). My guess is the optimization get into a loop w$$anonymous$$ch taking up all disk space...

It's hard for us to rollback the changes to check w$$anonymous$$ch scripts/plugins cause the problem, even though I remove the last compiling script (VungleBinding.m), it still happens...

Is there any way to debug w$$anonymous$$ch script causes it?