[llvm] [llvm-objdump] Handle .callgraph section (PR #151009)

[Prabhu Rajasekaran via llvm-commits]

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@@ -3131,6 +3225,207 @@ void Dumper::printSymbol(const SymbolRef &Symbol,
   outs() << ' ' << SymName << '\n';
 }
 
+static void printCallGraphInfo(ObjectFile *Obj) {
+  // Get function info through disassembly.
+  disassembleObject(Obj, /*InlineRelocs=*/false, outs());
+
+  // Get the .callgraph section.
+  StringRef CallGraphSectionName(".callgraph");
+  std::optional<object::SectionRef> CallGraphSection;
+  for (auto Sec : ToolSectionFilter(*Obj)) {
+    StringRef Name;
+    if (Expected<StringRef> NameOrErr = Sec.getName())
+      Name = *NameOrErr;
+    else
+      consumeError(NameOrErr.takeError());
+
+    if (Name == CallGraphSectionName) {
+      CallGraphSection = Sec;
+      break;
+    }
+  }
+  if (!CallGraphSection)
+    reportWarning("there is no .callgraph section", Obj->getFileName());
+
+  // Map type id to indirect call sites.
+  MapVector<uint64_t, SmallVector<uint64_t>> TypeIdToIndirCallSites;
+  // Map type id to indirect targets.
+  MapVector<uint64_t, SmallVector<uint64_t>> TypeIdToIndirTargets;
+  // Instructions that are not indirect calls but have a type id are ignored.
+  uint64_t IgnoredICallIdCount = 0;
+  // Number of valid indirect calls with type ids.
+  uint64_t ICallWithTypeIdCount = 0;
+  if (CallGraphSection) {
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Prabhuk wrote:

Should we handle direct callsites and print them out even if the CallgraphSection is empty?

https://github.com/llvm/llvm-project/pull/151009