[ELF] Don't check if symbols in .llvm.call-graph-profile are unorderable

[MaskRay]

Summary

There are too many reasonable cases that would be considered unorderable.

[ruiu]

Could you add a test?

[MaskRay]

In D53669#1274907, @ruiu wrote:

Could you add a test?

ToSym is never covered by a test. Is it fine?

[ruiu]

Maybe we should remove these warnings altogether as we discussed offline.

[Bigcheese]

I'm all in favor of removing the warnings. I was against adding them to begin with.

[ruiu]

Let's remove them, then.

[MaskRay]

Update title. Don't check if symbols are unorderable

[ruiu]

ELF/Driver.cpp

707–708

I don't think you need to leave any comment. In particular, this comment does not actually give any justification on why you are not doing it.

[MaskRay]

Delete comments

[ruiu]

LGTM

ELF/Driver.cpp

for (const Elf_CGProfile_Impl<ELFT> &CGPE : Obj->CGProfile) {
       auto *FromSec = dyn_cast_or_null<InputSectionBase>(FromSym->Section);
       auto *ToSec = dyn_cast_or_null<InputSectionBase>(ToSym->Section);
 
       // The profile from .llvm.call-graph-profile is conceptually affiliated to
       // FromSec. Don't warn unorderable symbol if FromSym is not absolute
       // (FromSec isn't null) and the section is discarded
       // (!FromSec->Repl->Live).
       //
-      // We also don't want to warn when ToSym is undefined or is in a shared
-      // object (as symbols in shared objects are fixed and unorderable).
+      // There are too many cases that ToSym would be considered unorderable:
+      // undefined, in a shared object (as symbols in shared objects are fixed
+      // and unorderable), or in a discarded section. Just don't check ToSym.
       //
       // The check used here is more relaxed (no warning if either FromSym or
       // ToSym is not Defined) for simplicity and there is no compelling reason
       // to warn on more cases.
-      if (!FromSec || FromSec->Repl->Live) {
+      if (!FromSec || FromSec->Repl->Live)
         warnUnorderableSymbol(FromSym);
-        warnUnorderableSymbol(ToSym);
-      }
       if (FromSec && ToSec)
         Config->CallGraphProfile[{FromSec, ToSec}] += CGPE.cgp_weight;
     }
   }
 }
 
 static bool getCompressDebugSections(opt::InputArgList &Args) {
   StringRef S = Args.getLastArgValue(OPT_compress_debug_sections, "none");
   if (S == "none")