We currently run these in swift-version 4 by default. This caused us to miss
some bugs that only occur in swift-version 5 due to initializer changes
happening in swift 5. This at least will allow us to catch such issues in the
future.
NOTE: I am also going to change objc_throwing_initializers.swift in the same
way, but after I fix the bugs that adding -swift-version 5 exposes therein
(which is actually <rdar://problem/59830255>)
This changes code generation a bit, because now the conditional
state bitmap uses a bit to track if the 'self' box was stored,
not if the 'self' value was consumed. In some cases, this
eliminates an extra bit, in other places it introduces an
extra bit, but it really doesn't matter because LLVM will
optimize this bit manipulation easily.
If the had a block where one predecessor had self initialized and
another had self uninitialized, DI would emit incorrect code for
the initialized case -- we would release self, then deallocate it,
causing a double-free.
This is the final part of <rdar://problem/21991742>.
Swift SVN r31149
