Index: llvm/trunk/test/tools/yaml2obj/empty.yaml
===================================================================
--- llvm/trunk/test/tools/yaml2obj/empty.yaml
+++ llvm/trunk/test/tools/yaml2obj/empty.yaml
@@ -0,0 +1,5 @@
+# RUN: echo "" | not yaml2obj 2>&1 | FileCheck %s
+# RUN: echo -n "" | not yaml2obj 2>&1 | FileCheck %s
+# RUN: echo " " | not yaml2obj 2>&1 | FileCheck %s
+# RUN: echo "  " | not yaml2obj 2>&1 | FileCheck %s
+# CHECK: yaml2obj: Error opening '-': Empty File.
Index: llvm/trunk/tools/yaml2obj/yaml2obj.cpp
===================================================================
--- llvm/trunk/tools/yaml2obj/yaml2obj.cpp
+++ llvm/trunk/tools/yaml2obj/yaml2obj.cpp
@@ -86,7 +86,10 @@
   if (!Buf)
     return 1;
 
-  yaml::Input YIn(Buf.get()->getBuffer());
+  StringRef Buffer = Buf.get()->getBuffer();
+  if (Buffer.trim().size() == 0)
+    error("yaml2obj: Error opening '" + Input + "': Empty File.");
+  yaml::Input YIn(Buffer);
 
   int Res = convertYAML(YIn, Out->os());
   if (Res == 0)