diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index 551cdef..21d4231 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -92,10 +92,10 @@
   // Globals for name and overview of program.  Program name is not a string to
   // avoid static ctor/dtor issues.
   std::string ProgramName;
-  const char *ProgramOverview;
+  StringRef ProgramOverview;
 
   // This collects additional help to be printed.
-  std::vector<const char *> MoreHelp;
+  std::vector<StringRef> MoreHelp;
 
   // This collects the different option categories that have been registered.
   SmallPtrSet<OptionCategory *, 16> RegisteredOptionCategories;
@@ -103,7 +103,7 @@
   // This collects the different subcommands that have been registered.
   SmallPtrSet<SubCommand *, 4> RegisteredSubCommands;
 
-  CommandLineParser() : ProgramOverview(nullptr), ActiveSubCommand(nullptr) {
+  CommandLineParser() : ActiveSubCommand(nullptr) {
     registerSubCommand(&*TopLevelSubCommand);
     registerSubCommand(&*AllSubCommands);
   }
@@ -111,9 +111,9 @@
   void ResetAllOptionOccurrences();
 
   bool ParseCommandLineOptions(int argc, const char *const *argv,
-                               const char *Overview, bool IgnoreErrors);
+                               StringRef Overview, bool IgnoreErrors);
 
-  void addLiteralOption(Option &Opt, SubCommand *SC, const char *Name) {
+  void addLiteralOption(Option &Opt, SubCommand *SC, StringRef Name) {
     if (Opt.hasArgStr())
       return;
     if (!SC->OptionsMap.insert(std::make_pair(Name, &Opt)).second) {
@@ -133,7 +133,7 @@
     }
   }
 
-  void addLiteralOption(Option &Opt, const char *Name) {
+  void addLiteralOption(Option &Opt, StringRef Name) {
     if (Opt.Subs.empty())
       addLiteralOption(Opt, &*TopLevelSubCommand, Name);
     else {
@@ -285,7 +285,7 @@
   void registerSubCommand(SubCommand *sub) {
     assert(count_if(RegisteredSubCommands,
                     [sub](const SubCommand *Sub) {
-                      return (sub->getName() != nullptr) &&
+                      return (!sub->getName().empty()) &&
                              (Sub->getName() == sub->getName());
                     }) == 0 &&
            "Duplicate subcommands");
@@ -300,7 +300,7 @@
             O->hasArgStr())
           addOption(O, sub);
         else
-          addLiteralOption(*O, sub, E.first().str().c_str());
+          addLiteralOption(*O, sub, E.first());
       }
     }
   }
@@ -312,7 +312,7 @@
   void reset() {
     ActiveSubCommand = nullptr;
     ProgramName.clear();
-    ProgramOverview = nullptr;
+    ProgramOverview = StringRef();
 
     MoreHelp.clear();
     RegisteredOptionCategories.clear();
@@ -330,18 +330,18 @@
   SubCommand *ActiveSubCommand;
 
   Option *LookupOption(SubCommand &Sub, StringRef &Arg, StringRef &Value);
-  SubCommand *LookupSubCommand(const char *Name);
+  SubCommand *LookupSubCommand(StringRef Name);
 };
 
 } // namespace
 
 static ManagedStatic<CommandLineParser> GlobalParser;
 
-void cl::AddLiteralOption(Option &O, const char *Name) {
+void cl::AddLiteralOption(Option &O, StringRef Name) {
   GlobalParser->addLiteralOption(O, Name);
 }
 
-extrahelp::extrahelp(const char *Help) : morehelp(Help) {
+extrahelp::extrahelp(StringRef Help) : morehelp(Help) {
   GlobalParser->MoreHelp.push_back(Help);
 }
 
@@ -428,13 +428,13 @@
   return I->second;
 }
 
-SubCommand *CommandLineParser::LookupSubCommand(const char *Name) {
-  if (Name == nullptr)
+SubCommand *CommandLineParser::LookupSubCommand(StringRef Name) {
+  if (Name.empty())
     return &*TopLevelSubCommand;
   for (auto S : RegisteredSubCommands) {
     if (S == &*AllSubCommands)
       continue;
-    if (S->getName() == nullptr)
+    if (S->getName().empty())
       continue;
 
     if (StringRef(S->getName()) == StringRef(Name))
@@ -534,7 +534,7 @@
         return Handler->error("requires a value!");
       // Steal the next argument, like for '-o filename'
       assert(argv && "null check");
-      Value = argv[++i];
+      Value = StringRef(argv[++i]);
     }
     break;
   case ValueDisallowed:
@@ -568,7 +568,7 @@
     if (i + 1 >= argc)
       return Handler->error("not enough values!");
     assert(argv && "null check");
-    Value = argv[++i];
+    Value = StringRef(argv[++i]);
 
     if (CommaSeparateAndAddOccurrence(Handler, i, ArgName, Value, MultiArg))
       return true;
@@ -726,7 +726,7 @@
     // End the token if this is whitespace.
     if (isWhitespace(Src[I])) {
       if (!Token.empty())
-        NewArgv.push_back(Saver.save(Token.c_str()));
+        NewArgv.push_back(Saver.save(StringRef(Token)));
       Token.clear();
       continue;
     }
@@ -737,7 +737,7 @@
 
   // Append the last token after hitting EOF with no whitespace.
   if (!Token.empty())
-    NewArgv.push_back(Saver.save(Token.c_str()));
+    NewArgv.push_back(Saver.save(StringRef(Token)));
   // Mark the end of response files
   if (MarkEOLs)
     NewArgv.push_back(nullptr);
@@ -818,7 +818,7 @@
     if (State == UNQUOTED) {
       // Whitespace means the end of the token.
       if (isWhitespace(Src[I])) {
-        NewArgv.push_back(Saver.save(Token.c_str()));
+        NewArgv.push_back(Saver.save(StringRef(Token)));
         Token.clear();
         State = INIT;
         // Mark the end of lines in response files
@@ -853,7 +853,7 @@
   }
   // Append the last token after hitting EOF with no whitespace.
   if (!Token.empty())
-    NewArgv.push_back(Saver.save(Token.c_str()));
+    NewArgv.push_back(Saver.save(StringRef(Token)));
   // Mark the end of response files
   if (MarkEOLs)
     NewArgv.push_back(nullptr);
@@ -953,7 +953,7 @@
   assert(envVar && "Environment variable name missing");
 
   // Get the environment variable they want us to parse options out of.
-  llvm::Optional<std::string> envValue = sys::Process::GetEnv(envVar);
+  llvm::Optional<std::string> envValue = sys::Process::GetEnv(StringRef(envVar));
   if (!envValue)
     return;
 
@@ -968,11 +968,11 @@
   // and hand it off to ParseCommandLineOptions().
   TokenizeGNUCommandLine(*envValue, Saver, newArgv);
   int newArgc = static_cast<int>(newArgv.size());
-  ParseCommandLineOptions(newArgc, &newArgv[0], Overview);
+  ParseCommandLineOptions(newArgc, &newArgv[0], StringRef(Overview));
 }
 
 bool cl::ParseCommandLineOptions(int argc, const char *const *argv,
-                                 const char *Overview, bool IgnoreErrors) {
+                                 StringRef Overview, bool IgnoreErrors) {
   return GlobalParser->ParseCommandLineOptions(argc, argv, Overview,
                                                IgnoreErrors);
 }
@@ -988,7 +988,7 @@
 
 bool CommandLineParser::ParseCommandLineOptions(int argc,
                                                 const char *const *argv,
-                                                const char *Overview,
+                                                StringRef Overview,
                                                 bool IgnoreErrors) {
   assert(hasOptions() && "No options specified!");
 
@@ -1001,7 +1001,7 @@
   argc = static_cast<int>(newArgv.size());
 
   // Copy the program name into ProgName, making sure not to overflow it.
-  ProgramName = sys::path::filename(argv[0]);
+  ProgramName = sys::path::filename(StringRef(argv[0]));
 
   ProgramOverview = Overview;
   bool ErrorParsing = false;
@@ -1017,7 +1017,7 @@
   if (argc >= 2 && argv[FirstArg][0] != '-') {
     // If the first argument specifies a valid subcommand, start processing
     // options from the second argument.
-    ChosenSubCommand = LookupSubCommand(argv[FirstArg]);
+    ChosenSubCommand = LookupSubCommand(StringRef(argv[FirstArg]));
     if (ChosenSubCommand != &*TopLevelSubCommand)
       FirstArg = 2;
   }
@@ -1098,19 +1098,19 @@
     if (argv[i][0] != '-' || argv[i][1] == 0 || DashDashFound) {
       // Positional argument!
       if (ActivePositionalArg) {
-        ProvidePositionalOption(ActivePositionalArg, argv[i], i);
+        ProvidePositionalOption(ActivePositionalArg, StringRef(argv[i]), i);
         continue; // We are done!
       }
 
       if (!PositionalOpts.empty()) {
-        PositionalVals.push_back(std::make_pair(argv[i], i));
+        PositionalVals.push_back(std::make_pair(StringRef(argv[i]), i));
 
         // All of the positional arguments have been fulfulled, give the rest to
         // the consume after option... if it's specified...
         //
         if (PositionalVals.size() >= NumPositionalRequired && ConsumeAfterOpt) {
           for (++i; i < argc; ++i)
-            PositionalVals.push_back(std::make_pair(argv[i], i));
+            PositionalVals.push_back(std::make_pair(StringRef(argv[i]), i));
           break; // Handle outside of the argument processing loop...
         }
 
@@ -1126,19 +1126,19 @@
       // If there is a positional argument eating options, check to see if this
       // option is another positional argument.  If so, treat it as an argument,
       // otherwise feed it to the eating positional.
-      ArgName = argv[i] + 1;
+      ArgName = StringRef(argv[i] + 1);
       // Eat leading dashes.
       while (!ArgName.empty() && ArgName[0] == '-')
         ArgName = ArgName.substr(1);
 
       Handler = LookupOption(*ChosenSubCommand, ArgName, Value);
       if (!Handler || Handler->getFormattingFlag() != cl::Positional) {
-        ProvidePositionalOption(ActivePositionalArg, argv[i], i);
+        ProvidePositionalOption(ActivePositionalArg, StringRef(argv[i]), i);
         continue; // We are done!
       }
 
     } else { // We start with a '-', must be an argument.
-      ArgName = argv[i] + 1;
+      ArgName = StringRef(argv[i] + 1);
       // Eat leading dashes.
       while (!ArgName.empty() && ArgName[0] == '-')
         ArgName = ArgName.substr(1);
@@ -1175,7 +1175,7 @@
         for (SmallVectorImpl<Option *>::iterator I = SinkOpts.begin(),
                                                  E = SinkOpts.end();
              I != E; ++I)
-          (*I)->addOccurrence(i, "", argv[i]);
+          (*I)->addOccurrence(i, "", StringRef(argv[i]));
       }
       continue;
     }
@@ -1389,7 +1389,8 @@
 // Return the width of the option tag for printing...
 size_t basic_parser_impl::getOptionWidth(const Option &O) const {
   size_t Len = O.ArgStr.size();
-  if (const char *ValName = getValueName())
+  auto ValName = getValueName();
+  if (!ValName.empty())
     Len += getValueStr(O, ValName).size() + 3;
 
   return Len + 6;
@@ -1402,7 +1403,8 @@
                                         size_t GlobalWidth) const {
   outs() << "  -" << O.ArgStr;
 
-  if (const char *ValName = getValueName())
+  auto ValName = getValueName();
+  if (!ValName.empty())
     outs() << "=<" << getValueStr(O, ValName) << '>';
 
   printHelpStr(O.HelpStr, GlobalWidth, getOptionWidth(O));
@@ -1512,11 +1514,11 @@
 // findOption - Return the option number corresponding to the specified
 // argument string.  If the option is not found, getNumOptions() is returned.
 //
-unsigned generic_parser_base::findOption(const char *Name) {
+unsigned generic_parser_base::findOption(StringRef Name) {
   unsigned e = getNumOptions();
 
   for (unsigned i = 0; i != e; ++i) {
-    if (strcmp(getOption(i), Name) == 0)
+    if (getOption(i) == Name)
       return i;
   }
   return e;
@@ -1527,12 +1529,12 @@
   if (O.hasArgStr()) {
     size_t Size = O.ArgStr.size() + 6;
     for (unsigned i = 0, e = getNumOptions(); i != e; ++i)
-      Size = std::max(Size, std::strlen(getOption(i)) + 8);
+      Size = std::max(Size, getOption(i).size() + 8);
     return Size;
   } else {
     size_t BaseSize = 0;
     for (unsigned i = 0, e = getNumOptions(); i != e; ++i)
-      BaseSize = std::max(BaseSize, std::strlen(getOption(i)) + 8);
+      BaseSize = std::max(BaseSize, getOption(i).size() + 8);
     return BaseSize;
   }
 }
@@ -1547,7 +1549,7 @@
     printHelpStr(O.HelpStr, GlobalWidth, O.ArgStr.size() + 6);
 
     for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
-      size_t NumSpaces = GlobalWidth - strlen(getOption(i)) - 8;
+      size_t NumSpaces = GlobalWidth - getOption(i).size() - 8;
       outs() << "    =" << getOption(i);
       outs().indent(NumSpaces) << " -   " << getDescription(i) << '\n';
     }
@@ -1555,9 +1557,9 @@
     if (!O.HelpStr.empty())
       outs() << "  " << O.HelpStr << '\n';
     for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
-      const char *Option = getOption(i);
+      auto Option = getOption(i);
       outs() << "    -" << Option;
-      printHelpStr(getDescription(i), GlobalWidth, std::strlen(Option) + 8);
+      printHelpStr(getDescription(i), GlobalWidth, Option.size() + 8);
     }
   }
 }
@@ -1579,7 +1581,7 @@
       continue;
 
     outs() << "= " << getOption(i);
-    size_t L = std::strlen(getOption(i));
+    size_t L = getOption(i).size();
     size_t NumSpaces = MaxOptWidth > L ? MaxOptWidth - L : 0;
     outs().indent(NumSpaces) << " (default: ";
     for (unsigned j = 0; j != NumOpts; ++j) {
@@ -1692,9 +1694,9 @@
 sortSubCommands(const SmallPtrSetImpl<SubCommand *> &SubMap,
                 SmallVectorImpl<std::pair<const char *, SubCommand *>> &Subs) {
   for (const auto &S : SubMap) {
-    if (S->getName() == nullptr)
+    if (S->getName().empty())
       continue;
-    Subs.push_back(std::make_pair(S->getName(), S));
+    Subs.push_back(std::make_pair(S->getName().data(), S));
   }
   array_pod_sort(Subs.begin(), Subs.end(), SubNameCompare);
 }
@@ -1717,7 +1719,7 @@
   void printSubCommands(StrSubCommandPairVector &Subs, size_t MaxSubLen) {
     for (const auto &S : Subs) {
       outs() << "  " << S.first;
-      if (S.second->getDescription()) {
+      if (!S.second->getDescription().empty()) {
         outs().indent(MaxSubLen - strlen(S.first));
         outs() << " - " << S.second->getDescription();
       }
@@ -1745,14 +1747,14 @@
     StrSubCommandPairVector Subs;
     sortSubCommands(GlobalParser->RegisteredSubCommands, Subs);
 
-    if (GlobalParser->ProgramOverview)
+    if (!GlobalParser->ProgramOverview.empty())
       outs() << "OVERVIEW: " << GlobalParser->ProgramOverview << "\n";
 
     if (Sub == &*TopLevelSubCommand)
       outs() << "USAGE: " << GlobalParser->ProgramName
              << " [subcommand] [options]";
     else {
-      if (Sub->getDescription() != nullptr) {
+      if (!Sub->getDescription().empty()) {
         outs() << "SUBCOMMAND '" << Sub->getName()
                << "': " << Sub->getDescription() << "\n\n";
       }
@@ -1814,7 +1816,7 @@
   // ordered before B's name. It returns a value greater equal zero otherwise.
   static int OptionCategoryCompare(OptionCategory *const *A,
                                    OptionCategory *const *B) {
-    return strcmp((*A)->getName(), (*B)->getName());
+    return (*A)->getName() == (*B)->getName();
   }
 
   // Make sure we inherit our base class's operator=()
@@ -1871,7 +1873,7 @@
       outs() << (*Category)->getName() << ":\n";
 
       // Check if description is set.
-      if ((*Category)->getDescription() != nullptr)
+      if (!(*Category)->getDescription().empty())
         outs() << (*Category)->getDescription() << "\n\n";
       else
         outs() << "\n";
@@ -2132,5 +2134,5 @@
 
 void LLVMParseCommandLineOptions(int argc, const char *const *argv,
                                  const char *Overview) {
-  llvm::cl::ParseCommandLineOptions(argc, argv, Overview, true);
+  llvm::cl::ParseCommandLineOptions(argc, argv, StringRef(Overview), true);
 }