[llvm] [BOLT][DWARF] Cleanup buffer initialization for DWO range writer (PR #97843)

[Sayhaan Siddiqui via llvm-commits]

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@@ -652,6 +652,7 @@ void DWARFRewriter::updateDebugInfo() {
         auto LegacyRangesSectionWriterByCU =
             std::make_unique<DebugRangesSectionWriter>();
         LegacyRangesSectionWriterByCU->initSection(CU);
+        LegacyRangesSectionWriterByCU->clearBuffer();
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sayhaan wrote:

Since we have each ranges writer its own instance, they all act the same and we still want the empty buffer at the beginning of debug_ranges which is in the main ranges writer. We could avoid creating empty ranges by passing some sort of flag into the constructor or some similar solution.

https://github.com/llvm/llvm-project/pull/97843