[llvm] [BOLT][DWARF] Skip processing DWO files with ID 0 (PR #154749)

[Alexander Yermolovich via llvm-commits]

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@@ -583,6 +583,15 @@ DWARFDie DIEBuilder::resolveDIEReference(
   uint64_t TmpRefOffset = RefOffset;
   if ((RefCU =
            getUnitForOffset(*this, *DwarfContext, TmpRefOffset, AttrSpec))) {
+    std::optional<uint64_t> DWOId = RefCU->getDWOId();
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ayermolo wrote:

Why is this necessary?

https://github.com/llvm/llvm-project/pull/154749