Summary:
Previously return type information for a function was derived from
return dag nodes. But this didn't work for dags with != return node. So
instead compute it directly from the LLVM function as is done for imports.
Differential Revision: http://reviews.llvm.org/D14593
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253251 91177308-0d34-0410-b5e6-96231b3b80d8