Index: llvm/trunk/include/llvm/MC/MCContext.h
===================================================================
--- llvm/trunk/include/llvm/MC/MCContext.h
+++ llvm/trunk/include/llvm/MC/MCContext.h
@@ -511,7 +511,7 @@
     /// Creates an entry in the dwarf file and directory tables.
     Expected<unsigned> getDwarfFile(StringRef Directory, StringRef FileName,
                                     unsigned FileNumber,
-                                    MD5::MD5Result *Checksum,
+                                    Optional<MD5::MD5Result> Checksum,
                                     Optional<StringRef> Source, unsigned CUID);
 
     bool isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID = 0);
@@ -554,7 +554,8 @@
     /// Specifies the "root" file and directory of the compilation unit.
     /// These are "file 0" and "directory 0" in DWARF v5.
     void setMCLineTableRootFile(unsigned CUID, StringRef CompilationDir,
-                                StringRef Filename, MD5::MD5Result *Checksum,
+                                StringRef Filename,
+                                Optional<MD5::MD5Result> Checksum,
                                 Optional<StringRef> Source) {
       getMCDwarfLineTable(CUID).setRootFile(CompilationDir, Filename, Checksum,
                                             Source);
Index: llvm/trunk/include/llvm/MC/MCDwarf.h
===================================================================
--- llvm/trunk/include/llvm/MC/MCDwarf.h
+++ llvm/trunk/include/llvm/MC/MCDwarf.h
@@ -55,7 +55,7 @@
 
   /// The MD5 checksum, if there is one. Non-owning pointer to data allocated
   /// in MCContext.
-  MD5::MD5Result *Checksum = nullptr;
+  Optional<MD5::MD5Result> Checksum;
 
   /// The source code of the file. Non-owning reference to data allocated in
   /// MCContext.
@@ -223,7 +223,7 @@
   MCDwarfLineTableHeader() = default;
 
   Expected<unsigned> tryGetFile(StringRef &Directory, StringRef &FileName,
-                                MD5::MD5Result *Checksum,
+                                Optional<MD5::MD5Result> Checksum,
                                 Optional<StringRef> &Source,
                                 unsigned FileNumber = 0);
   std::pair<MCSymbol *, MCSymbol *>
@@ -256,7 +256,7 @@
 
 public:
   void maybeSetRootFile(StringRef Directory, StringRef FileName,
-                        MD5::MD5Result *Checksum, Optional<StringRef> Source) {
+                        Optional<MD5::MD5Result> Checksum, Optional<StringRef> Source) {
     if (!Header.RootFile.Name.empty())
       return;
     Header.CompilationDir = Directory;
@@ -264,12 +264,12 @@
     Header.RootFile.DirIndex = 0;
     Header.RootFile.Checksum = Checksum;
     Header.RootFile.Source = Source;
-    Header.trackMD5Usage(Checksum);
+    Header.trackMD5Usage(Checksum.hasValue());
     Header.HasSource = Source.hasValue();
   }
 
   unsigned getFile(StringRef Directory, StringRef FileName,
-                   MD5::MD5Result *Checksum, Optional<StringRef> Source) {
+                   Optional<MD5::MD5Result> Checksum, Optional<StringRef> Source) {
     return cantFail(Header.tryGetFile(Directory, FileName, Checksum, Source));
   }
 
@@ -290,24 +290,24 @@
               Optional<MCDwarfLineStr> &LineStr) const;
 
   Expected<unsigned> tryGetFile(StringRef &Directory, StringRef &FileName,
-                                MD5::MD5Result *Checksum,
+                                Optional<MD5::MD5Result> Checksum,
                                 Optional<StringRef> Source,
                                 unsigned FileNumber = 0);
   unsigned getFile(StringRef &Directory, StringRef &FileName,
-                   MD5::MD5Result *Checksum, Optional<StringRef> &Source,
+                   Optional<MD5::MD5Result> Checksum, Optional<StringRef> &Source,
                    unsigned FileNumber = 0) {
     return cantFail(tryGetFile(Directory, FileName, Checksum, Source,
                                FileNumber));
   }
 
   void setRootFile(StringRef Directory, StringRef FileName,
-                   MD5::MD5Result *Checksum, Optional<StringRef> Source) {
+                   Optional<MD5::MD5Result> Checksum, Optional<StringRef> Source) {
     Header.CompilationDir = Directory;
     Header.RootFile.Name = FileName;
     Header.RootFile.DirIndex = 0;
     Header.RootFile.Checksum = Checksum;
     Header.RootFile.Source = Source;
-    Header.trackMD5Usage(Checksum);
+    Header.trackMD5Usage(Checksum.hasValue());
     Header.HasSource = Source.hasValue();
   }
 
Index: llvm/trunk/include/llvm/MC/MCStreamer.h
===================================================================
--- llvm/trunk/include/llvm/MC/MCStreamer.h
+++ llvm/trunk/include/llvm/MC/MCStreamer.h
@@ -781,7 +781,7 @@
   /// implements the DWARF2 '.file 4 "foo.c"' assembler directive.
   unsigned EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
                                   StringRef Filename,
-                                  MD5::MD5Result *Checksum = nullptr,
+                                  Optional<MD5::MD5Result> Checksum = None,
                                   Optional<StringRef> Source = None,
                                   unsigned CUID = 0) {
     return cantFail(
@@ -796,12 +796,12 @@
   /// '.file 4 "dir/foo.c" md5 "..." source "..."' assembler directive.
   virtual Expected<unsigned> tryEmitDwarfFileDirective(
       unsigned FileNo, StringRef Directory, StringRef Filename,
-      MD5::MD5Result *Checksum = nullptr, Optional<StringRef> Source = None,
+      Optional<MD5::MD5Result> Checksum = None, Optional<StringRef> Source = None,
       unsigned CUID = 0);
 
   /// Specify the "root" file of the compilation, using the ".file 0" extension.
   virtual void emitDwarfFile0Directive(StringRef Directory, StringRef Filename,
-                                       MD5::MD5Result *Checksum,
+                                       Optional<MD5::MD5Result> Checksum,
                                        Optional<StringRef> Source,
                                        unsigned CUID = 0);
 
Index: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -104,7 +104,7 @@
   // extend .file to support this.
   unsigned CUID = Asm->OutStreamer->hasRawTextSupport() ? 0 : getUniqueID();
   if (!File)
-    return Asm->OutStreamer->EmitDwarfFileDirective(0, "", "", nullptr, None, CUID);
+    return Asm->OutStreamer->EmitDwarfFileDirective(0, "", "", None, None, CUID);
   return Asm->OutStreamer->EmitDwarfFileDirective(
       0, File->getDirectory(), File->getFilename(), getMD5AsBytes(File),
       File->getSource(), CUID);
Index: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h
===================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -296,7 +296,7 @@
 
   /// If the \p File has an MD5 checksum, return it as an MD5Result
   /// allocated in the MCContext.
-  MD5::MD5Result *getMD5AsBytes(const DIFile *File) const;
+  Optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const;
 
 protected:
   ~DwarfUnit();
Index: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -289,21 +289,21 @@
     addUInt(Die, Attribute, dwarf::DW_FORM_data4, Integer);
 }
 
-MD5::MD5Result *DwarfUnit::getMD5AsBytes(const DIFile *File) const {
+Optional<MD5::MD5Result> DwarfUnit::getMD5AsBytes(const DIFile *File) const {
   assert(File);
   if (DD->getDwarfVersion() < 5)
-    return nullptr;
+    return None;
   Optional<DIFile::ChecksumInfo<StringRef>> Checksum = File->getChecksum();
   if (!Checksum || Checksum->Kind != DIFile::CSK_MD5)
-    return nullptr;
+    return None;
 
   // Convert the string checksum to an MD5Result for the streamer.
   // The verifier validates the checksum so we assume it's okay.
   // An MD5 checksum is 16 bytes.
   std::string ChecksumString = fromHex(Checksum->Value);
-  void *CKMem = Asm->OutStreamer->getContext().allocate(16, 1);
-  memcpy(CKMem, ChecksumString.data(), 16);
-  return reinterpret_cast<MD5::MD5Result *>(CKMem);
+  MD5::MD5Result CKMem;
+  std::copy(ChecksumString.begin(), ChecksumString.end(), CKMem.Bytes.data());
+  return CKMem;
 }
 
 unsigned DwarfTypeUnit::getOrCreateSourceID(const DIFile *File) {
Index: llvm/trunk/lib/MC/MCAsmStreamer.cpp
===================================================================
--- llvm/trunk/lib/MC/MCAsmStreamer.cpp
+++ llvm/trunk/lib/MC/MCAsmStreamer.cpp
@@ -223,11 +223,11 @@
   Expected<unsigned> tryEmitDwarfFileDirective(unsigned FileNo,
                                                StringRef Directory,
                                                StringRef Filename,
-                                               MD5::MD5Result *Checksum = 0,
+                                               Optional<MD5::MD5Result> Checksum = None,
                                                Optional<StringRef> Source = None,
                                                unsigned CUID = 0) override;
   void emitDwarfFile0Directive(StringRef Directory, StringRef Filename,
-                               MD5::MD5Result *Checksum,
+                               Optional<MD5::MD5Result> Checksum,
                                Optional<StringRef> Source,
                                unsigned CUID = 0) override;
   void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
@@ -1151,7 +1151,7 @@
 
 static void printDwarfFileDirective(unsigned FileNo, StringRef Directory,
                                     StringRef Filename,
-                                    MD5::MD5Result *Checksum,
+                                    Optional<MD5::MD5Result> Checksum,
                                     Optional<StringRef> Source,
                                     bool UseDwarfDirectory,
                                     raw_svector_ostream &OS) {
@@ -1184,7 +1184,7 @@
 
 Expected<unsigned> MCAsmStreamer::tryEmitDwarfFileDirective(
     unsigned FileNo, StringRef Directory, StringRef Filename,
-    MD5::MD5Result *Checksum, Optional<StringRef> Source, unsigned CUID) {
+    Optional<MD5::MD5Result> Checksum, Optional<StringRef> Source, unsigned CUID) {
   assert(CUID == 0 && "multiple CUs not supported by MCAsmStreamer");
 
   MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
@@ -1212,7 +1212,7 @@
 
 void MCAsmStreamer::emitDwarfFile0Directive(StringRef Directory,
                                             StringRef Filename,
-                                            MD5::MD5Result *Checksum,
+                                            Optional<MD5::MD5Result> Checksum,
                                             Optional<StringRef> Source,
                                             unsigned CUID) {
   assert(CUID == 0);
Index: llvm/trunk/lib/MC/MCContext.cpp
===================================================================
--- llvm/trunk/lib/MC/MCContext.cpp
+++ llvm/trunk/lib/MC/MCContext.cpp
@@ -572,12 +572,13 @@
 void MCContext::setGenDwarfRootFile(StringRef InputFileName, StringRef Buffer) {
   // MCDwarf needs the root file as well as the compilation directory.
   // If we find a '.file 0' directive that will supersede these values.
-  MD5::MD5Result *Cksum = nullptr;
+  Optional<MD5::MD5Result> Cksum;
   if (getDwarfVersion() >= 5) {
     MD5 Hash;
-    Cksum = (MD5::MD5Result *)allocate(sizeof(MD5::MD5Result), 1);
+    MD5::MD5Result Sum;
     Hash.update(Buffer);
-    Hash.final(*Cksum);
+    Hash.final(Sum);
+    Cksum = Sum;
   }
   // Canonicalize the root filename. It cannot be empty, and should not
   // repeat the compilation dir.
@@ -600,7 +601,7 @@
 Expected<unsigned> MCContext::getDwarfFile(StringRef Directory,
                                            StringRef FileName,
                                            unsigned FileNumber,
-                                           MD5::MD5Result *Checksum,
+                                           Optional<MD5::MD5Result> Checksum,
                                            Optional<StringRef> Source,
                                            unsigned CUID) {
   MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
Index: llvm/trunk/lib/MC/MCDwarf.cpp
===================================================================
--- llvm/trunk/lib/MC/MCDwarf.cpp
+++ llvm/trunk/lib/MC/MCDwarf.cpp
@@ -361,10 +361,10 @@
   }
   MCOS->EmitULEB128IntValue(DwarfFile.DirIndex); // Directory number.
   if (EmitMD5) {
-    MD5::MD5Result *Cksum = DwarfFile.Checksum;
+    const MD5::MD5Result &Cksum = *DwarfFile.Checksum;
     MCOS->EmitBinaryData(
-        StringRef(reinterpret_cast<const char *>(Cksum->Bytes.data()),
-                  Cksum->Bytes.size()));
+        StringRef(reinterpret_cast<const char *>(Cksum.Bytes.data()),
+                  Cksum.Bytes.size()));
   }
   if (HasSource) {
     if (LineStr)
@@ -536,7 +536,7 @@
 
 Expected<unsigned> MCDwarfLineTable::tryGetFile(StringRef &Directory,
                                                 StringRef &FileName,
-                                                MD5::MD5Result *Checksum,
+                                                Optional<MD5::MD5Result> Checksum,
                                                 Optional<StringRef> Source,
                                                 unsigned FileNumber) {
   return Header.tryGetFile(Directory, FileName, Checksum, Source, FileNumber);
@@ -545,7 +545,7 @@
 Expected<unsigned>
 MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
                                    StringRef &FileName,
-                                   MD5::MD5Result *Checksum,
+                                   Optional<MD5::MD5Result> Checksum,
                                    Optional<StringRef> &Source,
                                    unsigned FileNumber) {
   if (Directory == CompilationDir)
@@ -558,7 +558,7 @@
   // Keep track of whether any or all files have an MD5 checksum.
   // If any files have embedded source, they all must.
   if (MCDwarfFiles.empty()) {
-    trackMD5Usage(Checksum);
+    trackMD5Usage(Checksum.hasValue());
     HasSource = (Source != None);
   }
   if (FileNumber == 0) {
@@ -623,7 +623,7 @@
   File.Name = FileName;
   File.DirIndex = DirIndex;
   File.Checksum = Checksum;
-  trackMD5Usage(Checksum);
+  trackMD5Usage(Checksum.hasValue());
   File.Source = Source;
   if (Source)
     HasSource = true;
Index: llvm/trunk/lib/MC/MCParser/AsmParser.cpp
===================================================================
--- llvm/trunk/lib/MC/MCParser/AsmParser.cpp
+++ llvm/trunk/lib/MC/MCParser/AsmParser.cpp
@@ -3388,13 +3388,14 @@
       Ctx.setGenDwarfForAssembly(false);
     }
 
-    MD5::MD5Result *CKMem = nullptr;
+    Optional<MD5::MD5Result> CKMem;
     if (HasMD5) {
-      CKMem = (MD5::MD5Result *)Ctx.allocate(sizeof(MD5::MD5Result), 1);
+      MD5::MD5Result Sum;
       for (unsigned i = 0; i != 8; ++i) {
-        CKMem->Bytes[i] = uint8_t(MD5Hi >> ((7 - i) * 8));
-        CKMem->Bytes[i + 8] = uint8_t(MD5Lo >> ((7 - i) * 8));
+        Sum.Bytes[i] = uint8_t(MD5Hi >> ((7 - i) * 8));
+        Sum.Bytes[i + 8] = uint8_t(MD5Lo >> ((7 - i) * 8));
       }
+      CKMem = Sum;
     }
     if (HasSource) {
       char *SourceBuf = static_cast<char *>(Ctx.allocate(SourceString.size()));
Index: llvm/trunk/lib/MC/MCStreamer.cpp
===================================================================
--- llvm/trunk/lib/MC/MCStreamer.cpp
+++ llvm/trunk/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,