[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

694–695

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 (auto File : ObjectFiles) {
     for (const Elf_CGProfile_Impl<ELFT> &CGPE : Obj->CGProfile) {
       auto *FromSym = dyn_cast<Defined>(&Obj->getSymbol(CGPE.cgp_from));
       auto *ToSym = dyn_cast<Defined>(&Obj->getSymbol(CGPE.cgp_to));
       if (!FromSym || !ToSym)
         continue;
       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).
-      //
-      // 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) {
-        warnUnorderableSymbol(FromSym);
-        warnUnorderableSymbol(ToSym);
-      }
+      // Don't check if FromSym or ToSym is unorderable. There are too many
+      // reasonable cases that they would be considered unorderable.
       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");

test/ELF/cgprofile-obj-warn.s

-# REQUIRES: x86
-
-# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
-
-# RUN: ld.lld -e A %t -o /dev/null \
-# RUN:   -noinhibit-exec -icf=all 2>&1 | FileCheck %s
-
-    .section    .text.C,"ax",@progbits
-    .globl  C
-C:
-    mov poppy, %rax
-    retq
-
-B = 0x1234
-
-    .section    .text.A,"ax",@progbits
-    .globl  A
-A:
-    mov poppy, %rax
-    retq
-
-    .cg_profile A, B, 100
-    .cg_profile A, C, 40
-    .cg_profile B, C, 30
-    .cg_profile adena1, A, 30
-    .cg_profile A, adena2, 30
-    .cg_profile poppy, A, 30
-
-# CHECK: unable to order absolute symbol: B
-
-# RUN: ld.lld %t -o /dev/null \
-# RUN:   -noinhibit-exec -icf=all --no-warn-symbol-ordering 2>&1 \
-# RUN:   | FileCheck %s --check-prefix=NOWARN
-# NOWARN-NOT: unable to order