[llvm] [llvm-objdump] Support --mcpu=help/--mattr=help without -d (PR #165661)

[James Henderson via llvm-commits]

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@@ -3533,6 +3533,51 @@ commaSeparatedValues(const llvm::opt::InputArgList &InputArgs, int ID) {
   return Values;
 }
 
+static void mcpuHelp() {
+  Triple TheTriple;
+
+  if (!TripleName.empty()) {
+    TheTriple.setTriple(TripleName);
+  } else {
+    assert(!InputFilenames.empty());
+    Expected<OwningBinary<Binary>> OBinary = createBinary(InputFilenames[0]);
+    if (Error E = OBinary.takeError()) {
+      reportError(InputFilenames[0], "triple was not specified and could not "
+                                     "be inferred from the input file: " +
+                                         toString(std::move(E)));
+    }
+
+    Binary *Bin = OBinary->getBinary();
+    if (ObjectFile *Obj = dyn_cast<ObjectFile>(Bin)) {
+      TheTriple = Obj->makeTriple();
+    } else if (Archive *A = dyn_cast<Archive>(Bin)) {
+      Error Err = Error::success();
+      for (auto &C : A->children(Err)) {
+        Expected<std::unique_ptr<Binary>> ChildOrErr = C.getAsBinary();
+        if (!ChildOrErr)
+          // We don't report error because we don't disassemble it here.
+          continue;
+        if (ObjectFile *Obj = dyn_cast<ObjectFile>(&*ChildOrErr.get())) {
+          TheTriple = Obj->makeTriple();
+          break;
+        }
+      }
+      if (Err)
+        reportError(std::move(Err), A->getFileName());
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jh7370 wrote:

Test case?

https://github.com/llvm/llvm-project/pull/165661