NFC: Move API uses of MD5::MD5Result to Optional rather than a pointer.

Differential Revision: https://reviews.llvm.org/D60290

llvm-svn: 357736
diff --git a/llvm/lib/MC/MCStreamer.cpp b/llvm/lib/MC/MCStreamer.cpp
index 2d615f2..20d360f 100644
--- a/llvm/lib/MC/MCStreamer.cpp
+++ b/llvm/lib/MC/MCStreamer.cpp
@@ -204,7 +204,7 @@
 Expected<unsigned>
 MCStreamer::tryEmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
                                       StringRef Filename,
-                                      MD5::MD5Result *Checksum,
+                                      Optional<MD5::MD5Result> Checksum,
                                       Optional<StringRef> Source,
                                       unsigned CUID) {
   return getContext().getDwarfFile(Directory, Filename, FileNo, Checksum,
@@ -213,7 +213,7 @@
 
 void MCStreamer::emitDwarfFile0Directive(StringRef Directory,
                                          StringRef Filename,
-                                         MD5::MD5Result *Checksum,
+                                         Optional<MD5::MD5Result> Checksum,
                                          Optional<StringRef> Source,
                                          unsigned CUID) {
   getContext().setMCLineTableRootFile(CUID, Directory, Filename, Checksum,