[llvm] [BasicBlockSections] Introduce the path cloning profile format to BasicBlockSectionsProfileReader. (PR #67214)

[Rahman Lavaee via llvm-commits]

rlavaee wrote:

> The one major comment I have is that I am not convinced about the way you represent cloning decisions. I think a block cloning decision can be represented by exactly specifying the edge along which you want to clone. This keeps the specification really simple. I would like your opinion on this one. Further, whatever spec you go with, you must give more clear instructions on what constitutes a valid cloning directive and what isn't. I am inclined to choose a spec that is simple.

Expanded the function comment a bit more. The next patch (applying the cloning decisions) will implement the validation logic for path cloning.

https://github.com/llvm/llvm-project/pull/67214