[compiler-rt] [llvm] [ctxprof] Prepare profile format for flat profiles (PR #129626)

[Snehasish Kumar via llvm-commits]

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@@ -60,23 +62,30 @@ enum PGOCtxProfileBlockIDs {
 /// like value profiling - which would appear as additional records. For
 /// example, value profiling would produce a new record with a new record ID,
 /// containing the profiled values (much like the counters)
-class PGOCtxProfileWriter final {
+class PGOCtxProfileWriter : public ctx_profile::ProfileWriter {
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snehasish wrote:

Can still keep the final keyword here?

https://github.com/llvm/llvm-project/pull/129626