[clang] [llvm] Add support in LLVM BitstreamWriter to automatically choose abbrevs. (PR #147191)

[Chuanqi Xu via cfe-commits]

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@@ -2504,7 +2362,7 @@ void ASTWriter::WriteDeclAbbrevs() {
   // Type Source Info
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
   Abv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // TypeLoc
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ChuanqiXu9 wrote:

These specification still seems complex and not easy to extend.

https://github.com/llvm/llvm-project/pull/147191