MC: Don't emit the .llvm.call-graph-profile section into dwo files.

[pcc]

Summary

Noticed by inspection.

llvm/lib/MC/ELFObjectWriter.cpp

for (MCSection &Sec : Asm) {
 
     SectionIndexMap[&Section] = addToSectionTable(&Section);
     if (RelSection) {
       SectionIndexMap[RelSection] = addToSectionTable(RelSection);
       Relocations.push_back(RelSection);
     }
   }
 
-  MCSectionELF *CGProfileSection = nullptr;
-  if (!Asm.CGProfile.empty()) {
-    CGProfileSection = Ctx.getELFSection(".llvm.call-graph-profile",
-                                         ELF::SHT_LLVM_CALL_GRAPH_PROFILE,
-                                         ELF::SHF_EXCLUDE, 16, "");
-    SectionIndexMap[CGProfileSection] = addToSectionTable(CGProfileSection);
-  }
-
   for (MCSectionELF *Group : Groups) {
     align(Group->getAlignment());
 
     // Remember the offset into the file for this section.
     uint64_t SecStart = W.OS.tell();
 
     const MCSymbol *SignatureSymbol = Group->getGroup();
     assert(SignatureSymbol);
     write(uint32_t(ELF::GRP_COMDAT));
     for (const MCSectionELF *Member : GroupMembers[SignatureSymbol]) {
       uint32_t SecIndex = SectionIndexMap.lookup(Member);
       write(SecIndex);
     }
 
     uint64_t SecEnd = W.OS.tell();
     SectionOffsets[Group] = std::make_pair(SecStart, SecEnd);
   }
 
   if (Mode == DwoOnly) {
     // dwo files don't have symbol tables or relocations, but they do have
     // string tables.
     StrTabBuilder.finalize();
   } else {
+    MCSectionELF *CGProfileSection = nullptr;
+    if (!Asm.CGProfile.empty()) {
+      CGProfileSection = Ctx.getELFSection(".llvm.call-graph-profile",
+                                           ELF::SHT_LLVM_CALL_GRAPH_PROFILE,
+                                           ELF::SHF_EXCLUDE, 16, "");
+      SectionIndexMap[CGProfileSection] = addToSectionTable(CGProfileSection);
+    }
+
     // Compute symbol table information.
     computeSymbolTable(Asm, Layout, SectionIndexMap, RevGroupMap,
                        SectionOffsets);
 
     for (MCSectionELF *RelSection : Relocations) {
       align(RelSection->getAlignment());
 
       // Remember the offset into the file for this section.
       uint64_t SecStart = W.OS.tell();
 
       writeRelocations(Asm,
                        cast<MCSectionELF>(*RelSection->getAssociatedSection()));
 
       uint64_t SecEnd = W.OS.tell();
       SectionOffsets[RelSection] = std::make_pair(SecStart, SecEnd);
     }
-  }
 
     if (CGProfileSection) {
       uint64_t SecStart = W.OS.tell();
       for (const MCAssembler::CGProfileEntry &CGPE : Asm.CGProfile) {
         W.write<uint32_t>(CGPE.From->getSymbol().getIndex());
         W.write<uint32_t>(CGPE.To->getSymbol().getIndex());
         W.write<uint64_t>(CGPE.Count);
       }
       uint64_t SecEnd = W.OS.tell();
       SectionOffsets[CGProfileSection] = std::make_pair(SecStart, SecEnd);
     }
+  }
 
   {
     uint64_t SecStart = W.OS.tell();
     const MCSectionELF *Sec = createStringTable(Ctx);
     uint64_t SecEnd = W.OS.tell();
     SectionOffsets[Sec] = std::make_pair(SecStart, SecEnd);
   }
 

llvm/test/MC/ELF/cgprofile.s

 # RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -s -t -sd -elf-cg-profile | FileCheck %s
+# RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -split-dwarf-file %t.dwo -o - | llvm-readobj -s -t -sd -elf-cg-profile | FileCheck %s
+# RUN: llvm-readobj -s %t.dwo | FileCheck --check-prefix=DWO %s
 
   .section .test,"aw",@progbits
 a: .word b
 
   .cg_profile a, b, 32
   .cg_profile freq, a, 11
   .cg_profile late, late2, 20
   .cg_profile .L.local, b, 42

 # CHECK-NEXT:     To: late2
 # CHECK-NEXT:     Weight: 20
 # CHECK-NEXT:   }
 # CHECK-NEXT:   CGProfileEntry {
 # CHECK-NEXT:     From:
 # CHECK-NEXT:     To: b
 # CHECK-NEXT:     Weight: 42
 # CHECK-NEXT:   }
-# CHECK-NEXT: ]
+# CHECK-NEXT: ]
+
+# DWO-NOT: .llvm.call-graph-profile