Add in a caching mechanism so that forward declarations are replaced
with full types if they exist.

rdar://10809898 and rdar://10209967 and rdar://10400981

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150858 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed