[PATCH] D17006: Refactor PGO function naming and MD5 hashing support out of ProfileData

[Teresa Johnson via llvm-commits]

On Mon, Feb 8, 2016 at 9:04 PM, Xinliang David Li <davidxl at google.com>
wrote:

> On Mon, Feb 8, 2016 at 9:01 PM, Teresa Johnson <tejohnson at google.com>
> wrote:
> > tejohnson added a comment.
> >
> > In http://reviews.llvm.org/D17006#347035, @davidxl wrote:
> >
> >> This one LGTM. I am also expecting another interface like
> 'getFunctionGuid' to wrap around the MD5Hash method..
> >
> >
> > Do you mean to basically do MD5Hash(getGlobalIdentifier(...))?
>
> I think two interfaces are needed -- one takes Function*, while the
> other takes StringRef. The later is for cases where Global string id
> already known.
>

I'm still not clear on whether you want a new wrapper that does both the
MD5Hash and the getGlobalIdentifier? I.e. for the former do you mean
something like:
uint64_t Function::getGlobalUID(Function *F) {
   return MD5Hash(Function::getGlobalIdentifier(F->getName(),
F->getLinkage(), F->getParent()->getName());
}

and for the latter do you mean something like:
uint64_t Function::getGlobalUID(StringRef FuncName, LinkageType Linkage,
StringRef FileName) {
   return MD5Hash(Function::getGlobalIdentifier(FuncName, Linkage,
FileName));
}

or just

uint64_t Function::getGlobalUID(StringRef GlobalFuncName) {
   return MD5Hash(GlobalFuncName);
}




> >I could add that with the follow-on patch to use this in the ThinLTO
> function map.
>
> Ok -- It can be done a in separate patch. After that I will update PGO
> to use them.
>

Initially at least I would only be able to use a StringRef interface, as I
am pulling the linkage type out of the summary.

>
> >Although for now in the draft patch I am testing they are invoked in
> slightly different places (the MD5Hash is hidden within the
> FunctionInfoIndex methods which take a string, and getGlobalIdentifier is
> invoked as needed above that. And for PGO, it didn't look like MD5Hash and
> getPGOFuncName were invoked simultaneously.
>
> In most cases for PGO, the stringRef based interface will be used.
>
> thanks,
>
> David
>
> >
> >
> > http://reviews.llvm.org/D17006
> >
> >
> >
>



-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |  408-460-2413
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