[PATCH] D95929: [CSSPGO][llvm-profgen] Add brackets for context id to support extended binary format

[Hongtao Yu via Phabricator via llvm-commits]

hoy added inline comments.


================
Comment at: llvm/tools/llvm-profgen/ProfileGenerator.h:70
     // Enable context-sensitive functionalities in SampleProf
     FunctionSamples::ProfileIsCS = true;
     for (const auto &BI : BinarySampleCounters) {
----------------
wlei wrote:
> hoy wrote:
> > wlei wrote:
> > > wlei wrote:
> > > > hoy wrote:
> > > > > This should be removed since now every context has brackets.
> > > > It seems it also depends on this variable, see the code below. I saw your previous patch set it in the `SampleProfReader ` but llvm-profgen only use the `SampleProfWriter`.
> > > > 
> > > > ```
> > > >   /// Return function name with context.
> > > >   StringRef getNameWithContext(bool WithBracket = false) const {
> > > >     return FunctionSamples::ProfileIsCS
> > > >                ? Context.getNameWithContext(WithBracket)
> > > >                : Name;
> > > >   }
> > > > ```
> > > > 
> > > > I can understand we should automatically detect this, so how about to change the `Writer` to add some detection, say if the name has the bracket then set the `ProfileIsCS`?
> > > > 
> > > > 
> > > Seems there aren't a central place in `Writer` to detect it, the `write` function is override by different format.
> > > or how about code like this,  we ensure the `Context` is always valid for CS profile, right?
> > > ```
> > >   StringRef getNameWithContext(bool WithBracket = false) const {
> > >     return Context.getNameWithContext().size()?
> > >             Context.getNameWithContext(WithBracket) : Name ;
> > > ```
> > Yeah, we might end up doing the detection per writer. That should only be needed for `ProfileIsPseudoProbe` . For now we don't need to set `ProfileIsCS` because the contexts all have brackets and they can just be treated as regular function profiles by the existing writers. 
> I see, I guess you meant `ProfileIsCS` is false by default, so it will use the default `Name` variable like the regular function and the `Name` variable actually has the brackets.
> 
> Just fixed following this idea by setting the `Name`.
> ```
>  FProfile.setName(FContext.getNameWithContext(true));
> ```
Exactly. Also we can avoid setting `ProfileIsCS` in llvm-profgen now. It's yet ready to do the same for `ProfileIsProbeBased` since work will be needed on the profile writer side.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D95929/new/

https://reviews.llvm.org/D95929