The transform is somewhat involved, but the basic idea is simple: find
derived pointers that have been offset from the base pointer using gep
and replace the relocate of the derived pointer with a gep to the
relocated base pointer (with the same offset).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226060 91177308-0d34-0410-b5e6-96231b3b80d8