llvm-project

5223ddd8 - [ctxprof] Prepare profile format for flat profiles (#129626)

[ctxprof] Prepare profile format for flat profiles (#129626) The profile format has now a separate section called "Contexts" - there will be a corresponding one for flat profiles. The root has a separate tag because, in addition to not having a callsite ID as all the other context nodes have under it, it will have additional fields in subsequent patches. The rest of this patch amounts to a bit of refactorings in the reader/writer (for better reuse later) and tests fixups.