Index: llvm/include/llvm/Object/XCOFFObjectFile.h
===================================================================
--- llvm/include/llvm/Object/XCOFFObjectFile.h
+++ llvm/include/llvm/Object/XCOFFObjectFile.h
@@ -372,6 +372,8 @@
 
   Expected<ArrayRef<XCOFFRelocation32>>
   relocations(const XCOFFSectionHeader32 &) const;
+
+  static bool classof(const Binary *B) { return B->isXCOFF(); }
 }; // XCOFFObjectFile
 
 class XCOFFSymbolRef {
Index: llvm/unittests/Object/XCOFFObjectFileTest.cpp
===================================================================
--- llvm/unittests/Object/XCOFFObjectFileTest.cpp
+++ llvm/unittests/Object/XCOFFObjectFileTest.cpp
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Object/XCOFFObjectFile.h"
 #include "llvm/Testing/Support/Error.h"
 #include "gtest/gtest.h"
@@ -13,6 +14,24 @@
 using namespace llvm;
 using namespace llvm::object;
 
+TEST(XCOFFObjectFileTest, XCOFFObjectType) {
+  // Create an arbitrary object of a non-XCOFF type and test that
+  // dyn_cast<XCOFFObjectFile> returns null for it.
+  char Buf[sizeof(typename ELF64LE::Ehdr)] = {};
+  memcpy(Buf, "\177ELF", 4);
+
+  auto *EHdr = reinterpret_cast<typename ELF64LE::Ehdr *>(Buf);
+  EHdr->e_ident[llvm::ELF::EI_CLASS] = llvm::ELF::ELFCLASS64;
+  EHdr->e_ident[llvm::ELF::EI_DATA] = llvm::ELF::ELFDATA2LSB;
+
+  MemoryBufferRef Source(StringRef(Buf, sizeof(Buf)), "non-XCOFF");
+  Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
+      ObjectFile::createObjectFile(Source);
+  ASSERT_THAT_EXPECTED(ObjOrErr, Succeeded());
+
+  EXPECT_TRUE(dyn_cast<XCOFFObjectFile>((*ObjOrErr).get()) == nullptr);
+}
+
 TEST(XCOFFObjectFileTest, doesXCOFFTracebackTableBegin) {
   EXPECT_TRUE(doesXCOFFTracebackTableBegin({0, 0, 0, 0}));
   EXPECT_TRUE(doesXCOFFTracebackTableBegin({0, 0, 0, 0, 1}));