[Object] Define Archive::isEmpty().

llvm-svn: 282884
diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index 2870584..73761fa 100644
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -752,7 +752,7 @@
 
 Archive::child_iterator Archive::child_begin(Error &Err,
                                              bool SkipInternal) const {
-  if (Data.getBufferSize() == 8) // empty archive.
+  if (isEmpty())
     return child_end();
 
   if (SkipInternal)
@@ -968,4 +968,7 @@
   return Optional<Child>();
 }
 
+// Returns true if archive file contains no member file.
+bool Archive::isEmpty() const { return Data.getBufferSize() == 8; }
+
 bool Archive::hasSymbolTable() const { return !SymbolTable.empty(); }