Merging r369199:

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r369199 | yhs | 2019-08-18 00:12:00 +0200 (Sun, 18 Aug 2019) | 26 lines

[BPF] Fix bpf llvm-objdump issues.

Commit https://reviews.llvm.org/D57939 ("[DWARF] Refactor
RelocVisitor and fix computation of SHT_RELA-typed relocation entries)
made a change for relocation resolution when operating
on an object file.

The change unfortunately broke BPF as given SymbolValue (S) and
Addent (A), previously relocation is resolved to
    S + A
and after the change, it is resolved to
    S

This patch fixed the issue by resolving relocation correctly.

It looks not all relocation resolution reaches here and I did not
trace down exactly when. But I do find if the object file includes
codes in two different ELF sections than default ".text",
the above bug will be triggered.

This patch included a trivial two function source code to
demonstrate this issue. The relocation for .debug_loc is resolved
incorrectly due to this and llvm-objdump cannot display source
annotated assembly.

Differential Revision: https://reviews.llvm.org/D66372
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llvm-svn: 369359