metadata into a module flag in the auto-upgrader and make the ARC
contract pass read the marker as a module flag.
This is needed to fix a bug where ARC contract wasn't inserting the
retainRV marker when LTO was enabled, which caused objects returned
from a function to be auto-released.
rdar://problem/49464214
Differential Revision: https://reviews.llvm.org/D60303
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358047 91177308-0d34-0410-b5e6-96231b3b80d8