[llvm] [BOLT][DWARF][NFC] Split DIEBuilder::finish (PR #101244)

[Alexander Yermolovich via llvm-commits]

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@@ -127,6 +127,7 @@ class DIEBuilder {
   DWARFContext *DwarfContext{nullptr};
   DWARFUnit *SkeletonCU{nullptr};
   uint64_t UnitSize{0};
+  uint64_t DebugNamesUnitSize{0};
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ayermolo wrote:

add comments with explanation.

https://github.com/llvm/llvm-project/pull/101244