Commits
Joe Groff committed f817094c607
SILGen: Introduce writeback scopes. Define a new WritebackScope RAII object to mark the beginning and end of the lifetime of a set of writebacks. Add a writeback stack to SILGenFunction to keep track of active writebacks. Replace the ad-hoc writeback tracking in emitAssignToLValue with a WritebackScope. No functionality change just yet; this just sets the stage for handling writebacks in function arguments. Swift SVN r5402