Add a SymbolRef::getValue.

This returns either the symbol offset or address. Since it is not defined which
one, it never has to lookup the section and so never fails.

I will add users in the next commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240569 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed