This makes the interface simpler and more consistent with the interface for
.dSYM files and fixes a bug where llvm-symbolizer would not read the dwp if
it was asked to symbolize data before symbolizing code.
Differential Revision: https://reviews.llvm.org/D63114
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363025 91177308-0d34-0410-b5e6-96231b3b80d8