[llvm] [AsmPrinter][DebugNames] Implement DW_IDX_parent entries (PR #77457)

[Alexander Yermolovich via llvm-commits]

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@@ -395,36 +401,83 @@ void Dwarf5AccelTableWriter::Header::emit(Dwarf5AccelTableWriter &Ctx) {
   Asm->OutStreamer->emitBytes({AugmentationString, AugmentationStringSize});
 }
 
-static uint32_t constexpr LowerBitSize = dwarf::DW_IDX_type_hash;
+enum IdxParentEncoding : uint8_t {
+  NoIndexedParent = 0, // Parent information present but parent isn't indexed.
+  Ref4 = 1,            // Parent information present and parent is indexed.
+  NoParent = 2,        // Parent information missing.
+};
+
+static uint32_t constexpr NumBitsIdxParent = 2;
+
+uint8_t encodeIdxParent(std::optional<dwarf::Form> MaybeParentForm) {
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ayermolo wrote:

const?

https://github.com/llvm/llvm-project/pull/77457