[clang] [lld] [llvm] [Windows] Add support for emitting PGO/LTO magic strings in the Windows PE debug directory (PR #114260)

[Mikołaj Piróg via cfe-commits]

mikolaj-pirog wrote:

Thanks to the review above mentioning LTO, I realized that this solution has a problem with LTO, namely using LTO + PGO/PGU, will only emit the LTCG string in the binary. This is because right now the magic sections are only written in the COFF object file emission. I will also add the emission of this sections in the AsmPrinter, so they should appear in the bitcode files, and using LTO + PGO/PGU will emit both the "LTCG" and "PGO/PGU" strings

https://github.com/llvm/llvm-project/pull/114260