The old invalidation lattice was incorrect because changes to control flow could cause changes to the
call graph, so we've decided to change the way passes invalidate analysis. In the new scheme, the lattice
is replaced with a list of traits that passes preserve or invalidate. The current traits are Calls and Branches.
Now, passes report which traits they preserve, which is the opposite of the previous implementation where
passes needed to report what they invalidate.
Node: I tried to limit the changes in this commit to mechanical changes to ease the review. I will cleanup some
of the code in a following commit.
Swift SVN r26449
Note that I did not change any actual memory behavior. That will come via a
later cleanup phase. Since this is a correctness fix I wanted to only make
things more conservative.
rdar://18568601
Swift SVN r23311
We should also remove it from IRGen's Explosion API; IRGen
should always use maximal explosion, and SILGen will tell us
whether or not we need to put that in memory somewhere.
But that can be a later commit.
Swift SVN r14242
