[llvm] [llvm-readobj] Dump callgraph section info for ELF (PR #157499)

[James Henderson via llvm-commits]

================
@@ -8094,6 +8307,69 @@ template <class ELFT> void LLVMELFDumper<ELFT>::printCGProfile() {
   }
 }
 
+template <class ELFT> void LLVMELFDumper<ELFT>::printCallGraphInfo() {
+  if (!this->processCallGraphSection() || this->FuncCGInfos.empty())
+    return;
+
+  std::vector<Relocation<ELFT>> Relocations;
+  const Elf_Shdr *RelocSymTab = nullptr;
+  this->getCallGraphRelocations(Relocations, RelocSymTab);
+
+  auto PrintFunc = [](uint64_t FuncEntryPC, ArrayRef<std::string> FuncNames,
+                      ScopedPrinter &W) {
+    if (!FuncNames.empty())
+      W.printList("Names", FuncNames);
+    W.printHex("Address", FuncEntryPC);
+  };
+
+  auto PrintReloc = [&](uint64_t RelocOffset) {
+    auto Reloc = llvm::find_if(Relocations, [&](const Relocation<ELFT> &R) {
+      return R.Offset == RelocOffset;
+    });
+    if (Reloc == Relocations.end()) {
+      W.printHex("Offset", RelocOffset);
+      return;
+    }
+    Expected<RelSymbol<ELFT>> RelSymOrErr =
+        this->getRelocationTarget(*Reloc, RelocSymTab);
+    if (!RelSymOrErr) {
+      this->reportUniqueWarning(RelSymOrErr.takeError());
+      return;
+    }
+    if (!RelSymOrErr->Name.empty())
+      W.printString("Name", RelSymOrErr->Name);
+  };
+
+  auto PrintFunctionInfo = [&](uint64_t FuncEntryPC) {
+    if (this->Obj.getHeader().e_type != ELF::ET_REL) {
+      PrintFunc(FuncEntryPC, this->getFunctionNames(FuncEntryPC), W);
+      return;
+    }
+    PrintReloc(FuncEntryPC);
+  };
+
+  ListScope CGI(W, "CallGraph");
+  for (const auto &CGInfo : this->FuncCGInfos) {
+    DictScope D(W, "Function");
+    PrintFunctionInfo(CGInfo.FunctionAddress);
+    W.printNumber("Version", CGInfo.FormatVersionNumber);
+    W.printBoolean("IsIndirectTarget", CGInfo.IsIndirectTarget);
+    W.printHex("TypeId", CGInfo.FunctionTypeId);
+    W.printNumber("NumDirectCallees", CGInfo.DirectCallees.size());
+    {
+      ListScope DCs(W, "DirectCallees");
+      for (auto CalleePC : CGInfo.DirectCallees) {
+        DictScope D(W);
+        PrintFunctionInfo(CalleePC);
+      }
+    }
+    W.printNumber("NumIndirectTargetTypeIDs", CGInfo.IndirectTypeIDs.size());
+    auto IndirectTypeIdsList = SmallVector<uint64_t, 4>(
----------------
jh7370 wrote:

```suggestion
    SmallVector<uint64_t, 4> IndirectTypeIdsList(
```
This is more standard syntax in LLVM, I feel?

https://github.com/llvm/llvm-project/pull/157499