MemoryBuffer now return an error_code and returns a OwningPtr<MemoryBuffer> via an out parm.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121958 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-nm/llvm-nm.cpp b/tools/llvm-nm/llvm-nm.cpp
index 1661596..7daf792 100644
--- a/tools/llvm-nm/llvm-nm.cpp
+++ b/tools/llvm-nm/llvm-nm.cpp
@@ -144,10 +144,8 @@
   sys::Path aPath(Filename);
   // Note: Currently we do not support reading an archive from stdin.
   if (Filename == "-" || aPath.isBitcodeFile()) {
-    error_code ec;
-    std::auto_ptr<MemoryBuffer> Buffer(
-                   MemoryBuffer::getFileOrSTDIN(Filename, ec));
-    if (Buffer.get() == 0)
+    OwningPtr<MemoryBuffer> Buffer;
+    if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buffer))
       ErrorMessage = ec.message();
     Module *Result = 0;
     if (Buffer.get())