[PATCH] D85628: [HotColdSplitting] Add command line options for supplying cold function names via user input.

[Ruijie Fang via Phabricator via llvm-commits]

rjf added a comment.

In D85628#2214429 <https://reviews.llvm.org/D85628#2214429>, @yfeldblum wrote:

> In D85628#2214314 <https://reviews.llvm.org/D85628#2214314>, @hiraditya wrote:
>
>> If there was a way to provide handwritten profile/coverage file, maybe that would work in absence of profile information?
>
> I am not sure I see a need for profiles here.
>
> I don't think we need profile information. We just need `__cxa_guard_acquire` to be marked cold, and for the compiler to infer coldness of code in the same block as a call to something marked as cold. (Apparently HCS does this?)

I think you missed Aditya's point here: he's saying that certain things like outlining `__cxa*` functions might be unwise to do in general, hence leaving a command line option to supply user-defined cold func names might be a good idea; and alternatively to JF's point, he's saying if the command line option sounds too unprincipled we can also take in a more principled file format like code coverage or something like that.

And also, yes, HCS propagates coldness information through the CFG.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D85628/new/

https://reviews.llvm.org/D85628