Object: Implement casting for concrete classes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142314 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Object/ELFObjectFile.cpp b/lib/Object/ELFObjectFile.cpp
index e13c312..7a992e2 100644
--- a/lib/Object/ELFObjectFile.cpp
+++ b/lib/Object/ELFObjectFile.cpp
@@ -377,6 +377,11 @@
   uint64_t getStringTableIndex() const;
   ELF::Elf64_Word getSymbolTableIndex(const Elf_Sym *symb) const;
   const Elf_Shdr *getSection(const Elf_Sym *symb) const;
+
+  static inline bool classof(const Binary *v) {
+    return v->getType() == isELF;
+  }
+  static inline bool classof(const ELFObjectFile *v) { return true; }
 };
 } // end namespace