From: Mehdi Amini <mehdi.amini@apple.com>
Date: Sat, 1 Oct 2016 03:43:20 +0000 (+0000)
Subject: Use StringRef in CommandLine Options handling (NFC)
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b7d8ee46b4656ec2da22f90a5d152acb5a306aff;p=llvm

Use StringRef in CommandLine Options handling (NFC)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283007 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/CodeGen/MachinePassRegistry.h b/include/llvm/CodeGen/MachinePassRegistry.h
index 8fb9ebd60f5..db914b1f8bc 100644
--- a/include/llvm/CodeGen/MachinePassRegistry.h
+++ b/include/llvm/CodeGen/MachinePassRegistry.h
@@ -132,9 +132,9 @@ public:
     // Add existing passes to option.
     for (RegistryClass *Node = RegistryClass::getList();
          Node; Node = Node->getNext()) {
-      this->addLiteralOption(Node->getName().data(),
+      this->addLiteralOption(Node->getName(),
                       (typename RegistryClass::FunctionPassCtor)Node->getCtor(),
-                             Node->getDescription().data());
+                             Node->getDescription());
     }
 
     // Make sure we listen for list changes.
@@ -144,12 +144,10 @@ public:
   // Implement the MachinePassRegistryListener callbacks.
   //
   void NotifyAdd(StringRef N, MachinePassCtor C, StringRef D) override {
-    this->addLiteralOption(N.data(),
-                           (typename RegistryClass::FunctionPassCtor)C,
-                           D.data());
+    this->addLiteralOption(N, (typename RegistryClass::FunctionPassCtor)C, D);
   }
   void NotifyRemove(StringRef N) override {
-    this->removeLiteralOption(N.data());
+    this->removeLiteralOption(N);
   }
 };
 
diff --git a/include/llvm/Support/CommandLine.h b/include/llvm/Support/CommandLine.h
index 1c1345516c2..f2e8b281716 100644
--- a/include/llvm/Support/CommandLine.h
+++ b/include/llvm/Support/CommandLine.h
@@ -47,7 +47,7 @@ namespace cl {
 // ParseCommandLineOptions - Command line option processing entry point.
 //
 bool ParseCommandLineOptions(int argc, const char *const *argv,
-                             const char *Overview = nullptr,
+                             StringRef Overview = "",
                              bool IgnoreErrors = false);
 
 //===----------------------------------------------------------------------===//
@@ -55,7 +55,7 @@ bool ParseCommandLineOptions(int argc, const char *const *argv,
 //                           entry point.
 //
 void ParseEnvironmentOptions(const char *progName, const char *envvar,
-                             const char *Overview = nullptr);
+                             const char *Overview = "");
 
 ///===---------------------------------------------------------------------===//
 /// SetVersionPrinter - Override the default (LLVM specific) version printer
@@ -89,7 +89,7 @@ class Option;
 ///
 /// Literal options are used by some parsers to register special option values.
 /// This is how the PassNameParser registers pass names for opt.
-void AddLiteralOption(Option &O, const char *Name);
+void AddLiteralOption(Option &O, StringRef Name);
 
 //===----------------------------------------------------------------------===//
 // Flags permitted to be passed to command line arguments
@@ -157,18 +157,18 @@ enum MiscFlags {             // Miscellaneous flags to adjust argument
 //
 class OptionCategory {
 private:
-  const char *const Name;
-  const char *const Description;
+  StringRef const Name;
+  StringRef const Description;
   void registerCategory();
 
 public:
-  OptionCategory(const char *const Name,
-                 const char *const Description = nullptr)
+  OptionCategory(StringRef const Name,
+                 StringRef const Description = "")
       : Name(Name), Description(Description) {
     registerCategory();
   }
-  const char *getName() const { return Name; }
-  const char *getDescription() const { return Description; }
+  StringRef getName() const { return Name; }
+  StringRef getDescription() const { return Description; }
 };
 
 // The general Option Category (used as default category).
@@ -179,17 +179,17 @@ extern OptionCategory GeneralCategory;
 //
 class SubCommand {
 private:
-  const char *const Name = nullptr;
-  const char *const Description = nullptr;
+  StringRef Name = "";
+  StringRef Description = "";
 
 protected:
   void registerSubCommand();
   void unregisterSubCommand();
 
 public:
-  SubCommand(const char *const Name, const char *const Description = nullptr)
+  SubCommand(StringRef Name, StringRef Description = "")
       : Name(Name), Description(Description) {
-    registerSubCommand();
+        registerSubCommand();
   }
   SubCommand() {}
 
@@ -197,8 +197,8 @@ public:
 
   operator bool() const;
 
-  const char *getName() const { return Name; }
-  const char *getDescription() const { return Description; }
+  StringRef getName() const { return Name; }
+  StringRef getDescription() const { return Description; }
 
   SmallVector<Option *, 4> PositionalOpts;
   SmallVector<Option *, 4> SinkOpts;
@@ -353,16 +353,16 @@ public:
 
 // desc - Modifier to set the description shown in the -help output...
 struct desc {
-  const char *Desc;
-  desc(const char *Str) : Desc(Str) {}
+  StringRef Desc;
+  desc(StringRef Str) : Desc(Str) {}
   void apply(Option &O) const { O.setDescription(Desc); }
 };
 
 // value_desc - Modifier to set the value description shown in the -help
 // output...
 struct value_desc {
-  const char *Desc;
-  value_desc(const char *Str) : Desc(Str) {}
+  StringRef Desc;
+  value_desc(StringRef Str) : Desc(Str) {}
   void apply(Option &O) const { O.setValueStr(Desc); }
 };
 
@@ -569,20 +569,20 @@ template <class DataType> class ValuesClass {
   // Use a vector instead of a map, because the lists should be short,
   // the overhead is less, and most importantly, it keeps them in the order
   // inserted so we can print our option out nicely.
-  SmallVector<std::pair<const char *, std::pair<int, const char *>>, 4> Values;
+  SmallVector<std::pair<StringRef , std::pair<int, StringRef >>, 4> Values;
   void processValues(va_list Vals);
 
 public:
-  ValuesClass(const char *EnumName, DataType Val, const char *Desc,
+  ValuesClass(StringRef EnumName, DataType Val, StringRef Desc,
               va_list ValueArgs) {
     // Insert the first value, which is required.
     Values.push_back(std::make_pair(EnumName, std::make_pair(Val, Desc)));
 
     // Process the varargs portion of the values...
-    while (const char *enumName = va_arg(ValueArgs, const char *)) {
+    while (const char *enumName = va_arg(ValueArgs, const char * )) {
       DataType EnumVal = static_cast<DataType>(va_arg(ValueArgs, int));
-      const char *EnumDesc = va_arg(ValueArgs, const char *);
-      Values.push_back(std::make_pair(enumName, // Add value to value map
+      auto EnumDesc = StringRef(va_arg(ValueArgs, const char * ));
+      Values.push_back(std::make_pair(StringRef(enumName), // Add value to value map
                                       std::make_pair(EnumVal, EnumDesc)));
     }
   }
@@ -596,7 +596,7 @@ public:
 
 template <class DataType>
 ValuesClass<DataType> LLVM_END_WITH_NULL
-values(const char *Arg, DataType Val, const char *Desc, ...) {
+values(StringRef Arg, DataType Val, StringRef Desc, ...) {
   va_list ValueArgs;
   va_start(ValueArgs, Desc);
   ValuesClass<DataType> Vals(Arg, Val, Desc, ValueArgs);
@@ -620,10 +620,10 @@ class generic_parser_base {
 protected:
   class GenericOptionInfo {
   public:
-    GenericOptionInfo(const char *name, const char *helpStr)
+    GenericOptionInfo(StringRef name, StringRef helpStr)
         : Name(name), HelpStr(helpStr) {}
-    const char *Name;
-    const char *HelpStr;
+    StringRef Name;
+    StringRef HelpStr;
   };
 
 public:
@@ -637,10 +637,10 @@ public:
   virtual unsigned getNumOptions() const = 0;
 
   // getOption - Return option name N.
-  virtual const char *getOption(unsigned N) const = 0;
+  virtual StringRef getOption(unsigned N) const = 0;
 
   // getDescription - Return description N
-  virtual const char *getDescription(unsigned N) const = 0;
+  virtual StringRef getDescription(unsigned N) const = 0;
 
   // Return the width of the option tag for printing...
   virtual size_t getOptionWidth(const Option &O) const;
@@ -699,7 +699,7 @@ public:
   // findOption - Return the option number corresponding to the specified
   // argument string.  If the option is not found, getNumOptions() is returned.
   //
-  unsigned findOption(const char *Name);
+  unsigned findOption(StringRef Name);
 
 protected:
   Option &Owner;
@@ -715,7 +715,7 @@ template <class DataType> class parser : public generic_parser_base {
 protected:
   class OptionInfo : public GenericOptionInfo {
   public:
-    OptionInfo(const char *name, DataType v, const char *helpStr)
+    OptionInfo(StringRef name, DataType v, StringRef helpStr)
         : GenericOptionInfo(name, helpStr), V(v) {}
     OptionValue<DataType> V;
   };
@@ -727,8 +727,8 @@ public:
 
   // Implement virtual functions needed by generic_parser_base
   unsigned getNumOptions() const override { return unsigned(Values.size()); }
-  const char *getOption(unsigned N) const override { return Values[N].Name; }
-  const char *getDescription(unsigned N) const override {
+  StringRef getOption(unsigned N) const override { return Values[N].Name; }
+  StringRef getDescription(unsigned N) const override {
     return Values[N].HelpStr;
   }
 
@@ -757,7 +757,7 @@ public:
   /// addLiteralOption - Add an entry to the mapping table.
   ///
   template <class DT>
-  void addLiteralOption(const char *Name, const DT &V, const char *HelpStr) {
+  void addLiteralOption(StringRef Name, const DT &V, StringRef HelpStr) {
     assert(findOption(Name) == Values.size() && "Option already exists!");
     OptionInfo X(Name, static_cast<DataType>(V), HelpStr);
     Values.push_back(X);
@@ -766,7 +766,7 @@ public:
 
   /// removeLiteralOption - Remove the specified option.
   ///
-  void removeLiteralOption(const char *Name) {
+  void removeLiteralOption(StringRef Name) {
     unsigned N = findOption(Name);
     assert(N != Values.size() && "Option not found!");
     Values.erase(Values.begin() + N);
@@ -802,7 +802,7 @@ public:
   void printOptionNoValue(const Option &O, size_t GlobalWidth) const;
 
   // getValueName - Overload in subclass to provide a better default value.
-  virtual const char *getValueName() const { return "value"; }
+  virtual StringRef getValueName() const { return "value"; }
 
   // An out-of-line virtual method to provide a 'home' for this class.
   virtual void anchor();
@@ -844,7 +844,7 @@ public:
   }
 
   // getValueName - Do not print =<value> at all.
-  const char *getValueName() const override { return nullptr; }
+  StringRef getValueName() const override { return StringRef(); }
 
   void printOptionDiff(const Option &O, bool V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -870,7 +870,7 @@ public:
   }
 
   // getValueName - Do not print =<value> at all.
-  const char *getValueName() const override { return nullptr; }
+  StringRef getValueName() const override { return StringRef(); }
 
   void printOptionDiff(const Option &O, boolOrDefault V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -892,7 +892,7 @@ public:
   bool parse(Option &O, StringRef ArgName, StringRef Arg, int &Val);
 
   // getValueName - Overload in subclass to provide a better default value.
-  const char *getValueName() const override { return "int"; }
+  StringRef getValueName() const override { return "int"; }
 
   void printOptionDiff(const Option &O, int V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -914,7 +914,7 @@ public:
   bool parse(Option &O, StringRef ArgName, StringRef Arg, unsigned &Val);
 
   // getValueName - Overload in subclass to provide a better default value.
-  const char *getValueName() const override { return "uint"; }
+  StringRef getValueName() const override { return "uint"; }
 
   void printOptionDiff(const Option &O, unsigned V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -939,7 +939,7 @@ public:
              unsigned long long &Val);
 
   // getValueName - Overload in subclass to provide a better default value.
-  const char *getValueName() const override { return "uint"; }
+  StringRef getValueName() const override { return "uint"; }
 
   void printOptionDiff(const Option &O, unsigned long long V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -961,7 +961,7 @@ public:
   bool parse(Option &O, StringRef ArgName, StringRef Arg, double &Val);
 
   // getValueName - Overload in subclass to provide a better default value.
-  const char *getValueName() const override { return "number"; }
+  StringRef getValueName() const override { return "number"; }
 
   void printOptionDiff(const Option &O, double V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -983,7 +983,7 @@ public:
   bool parse(Option &O, StringRef ArgName, StringRef Arg, float &Val);
 
   // getValueName - Overload in subclass to provide a better default value.
-  const char *getValueName() const override { return "number"; }
+  StringRef getValueName() const override { return "number"; }
 
   void printOptionDiff(const Option &O, float V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -1008,7 +1008,7 @@ public:
   }
 
   // getValueName - Overload in subclass to provide a better default value.
-  const char *getValueName() const override { return "string"; }
+  StringRef getValueName() const override { return "string"; }
 
   void printOptionDiff(const Option &O, StringRef V, const OptVal &Default,
                        size_t GlobalWidth) const;
@@ -1033,7 +1033,7 @@ public:
   }
 
   // getValueName - Overload in subclass to provide a better default value.
-  const char *getValueName() const override { return "char"; }
+  StringRef getValueName() const override { return "char"; }
 
   void printOptionDiff(const Option &O, char V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -1101,17 +1101,17 @@ template <class Mod> struct applicator {
 
 // Handle const char* as a special case...
 template <unsigned n> struct applicator<char[n]> {
-  template <class Opt> static void opt(const char *Str, Opt &O) {
+  template <class Opt> static void opt(StringRef Str, Opt &O) {
     O.setArgStr(Str);
   }
 };
 template <unsigned n> struct applicator<const char[n]> {
-  template <class Opt> static void opt(const char *Str, Opt &O) {
+  template <class Opt> static void opt(StringRef Str, Opt &O) {
     O.setArgStr(Str);
   }
 };
-template <> struct applicator<const char *> {
-  template <class Opt> static void opt(const char *Str, Opt &O) {
+template <> struct applicator<StringRef > {
+  template <class Opt> static void opt(StringRef Str, Opt &O) {
     O.setArgStr(Str);
   }
 };
@@ -1688,8 +1688,8 @@ struct aliasopt {
 // printed to stderr at the end of the regular help, just before
 // exit is called.
 struct extrahelp {
-  const char *morehelp;
-  explicit extrahelp(const char *help);
+  StringRef morehelp;
+  explicit extrahelp(StringRef help);
 };
 
 void PrintVersionMessage();
diff --git a/include/llvm/Support/Options.h b/include/llvm/Support/Options.h
index 7b61b2308f5..9019804d24e 100644
--- a/include/llvm/Support/Options.h
+++ b/include/llvm/Support/Options.h
@@ -93,7 +93,7 @@ public:
   /// option stores (\p ValT), the class that will read the option (\p Base),
   /// and the member that the class will store the data into (\p Mem).
   template <typename ValT, typename Base, ValT(Base::*Mem)>
-  static void registerOption(const char *ArgStr, const char *Desc,
+  static void registerOption(StringRef ArgStr, StringRef Desc,
                              const ValT &InitValue) {
     cl::opt<ValT> *Option = new cl::opt<ValT>(ArgStr, cl::desc(Desc),
                                               cl::Hidden, cl::init(InitValue));
diff --git a/lib/Support/CommandLine.cpp b/lib/Support/CommandLine.cpp
index 551cdefcbe4..21d4231215a 100644
--- a/lib/Support/CommandLine.cpp
+++ b/lib/Support/CommandLine.cpp
@@ -92,10 +92,10 @@ public:
   // 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 @@ public:
   // 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 @@ public:
   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 @@ public:
     }
   }
 
-  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 @@ public:
   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 @@ public:
             O->hasArgStr())
           addOption(O, sub);
         else
-          addLiteralOption(*O, sub, E.first().str().c_str());
+          addLiteralOption(*O, sub, E.first());
       }
     }
   }
@@ -312,7 +312,7 @@ public:
   void reset() {
     ActiveSubCommand = nullptr;
     ProgramName.clear();
-    ProgramOverview = nullptr;
+    ProgramOverview = StringRef();
 
     MoreHelp.clear();
     RegisteredOptionCategories.clear();
@@ -330,18 +330,18 @@ private:
   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 @@ Option *CommandLineParser::LookupOption(SubCommand &Sub, StringRef &Arg,
   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 @@ static inline bool ProvideOption(Option *Handler, StringRef ArgName,
         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 @@ static inline bool ProvideOption(Option *Handler, StringRef ArgName,
     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 @@ void cl::TokenizeGNUCommandLine(StringRef Src, StringSaver &Saver,
     // 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 @@ void cl::TokenizeGNUCommandLine(StringRef Src, StringSaver &Saver,
 
   // 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 @@ void cl::TokenizeWindowsCommandLine(StringRef Src, StringSaver &Saver,
     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 @@ void cl::TokenizeWindowsCommandLine(StringRef Src, StringSaver &Saver,
   }
   // 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 @@ void cl::ParseEnvironmentOptions(const char *progName, const char *envVar,
   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 @@ void cl::ParseEnvironmentOptions(const char *progName, const char *envVar,
   // 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 @@ void CommandLineParser::ResetAllOptionOccurrences() {
 
 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 @@ bool CommandLineParser::ParseCommandLineOptions(int argc,
   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 @@ bool CommandLineParser::ParseCommandLineOptions(int argc,
   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 @@ bool CommandLineParser::ParseCommandLineOptions(int argc,
     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 @@ bool CommandLineParser::ParseCommandLineOptions(int argc,
       // 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 @@ bool CommandLineParser::ParseCommandLineOptions(int argc,
         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 @@ void alias::printOptionInfo(size_t GlobalWidth) const {
 // 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 @@ void basic_parser_impl::printOptionInfo(const Option &O,
                                         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 @@ bool parser<float>::parse(Option &O, StringRef ArgName, StringRef Arg,
 // 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 @@ size_t generic_parser_base::getOptionWidth(const Option &O) const {
   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 @@ void generic_parser_base::printOptionInfo(const Option &O,
     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 @@ void generic_parser_base::printOptionInfo(const Option &O,
     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 @@ void generic_parser_base::printGenericOptionDiff(
       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 @@ static void
 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 @@ protected:
   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 @@ public:
     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 @@ public:
   // 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 @@ protected:
       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 cl::ResetAllOptionOccurrences() {
 
 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);
 }
diff --git a/tools/llvm-stress/llvm-stress.cpp b/tools/llvm-stress/llvm-stress.cpp
index 0b887ea9b4c..731a24d0ac2 100644
--- a/tools/llvm-stress/llvm-stress.cpp
+++ b/tools/llvm-stress/llvm-stress.cpp
@@ -67,7 +67,7 @@ public:
     return false;
   }
 
-  const char *getValueName() const override { return "IR scalar type"; }
+  StringRef getValueName() const override { return "IR scalar type"; }
 };
 }
 
diff --git a/unittests/Support/CommandLineTest.cpp b/unittests/Support/CommandLineTest.cpp
index 9b24c1e40bc..e227586ba3e 100644
--- a/unittests/Support/CommandLineTest.cpp
+++ b/unittests/Support/CommandLineTest.cpp
@@ -76,8 +76,8 @@ public:
 
 class StackSubCommand : public cl::SubCommand {
 public:
-  StackSubCommand(const char *const Name,
-                  const char *const Description = nullptr)
+  StackSubCommand(StringRef Name,
+                  StringRef Description = StringRef())
       : SubCommand(Name, Description) {}
 
   StackSubCommand() : SubCommand() {}
@@ -168,7 +168,7 @@ typedef void ParserFunction(StringRef Source, StringSaver &Saver,
                             SmallVectorImpl<const char *> &NewArgv,
                             bool MarkEOLs);
 
-void testCommandLineTokenizer(ParserFunction *parse, const char *Input,
+void testCommandLineTokenizer(ParserFunction *parse, StringRef Input,
                               const char *const Output[], size_t OutputSize) {
   SmallVector<const char *, 0> Actual;
   BumpPtrAllocator A;
@@ -182,7 +182,7 @@ void testCommandLineTokenizer(ParserFunction *parse, const char *Input,
 }
 
 TEST(CommandLineTest, TokenizeGNUCommandLine) {
-  const char *Input =
+  const char Input[] =
       "foo\\ bar \"foo bar\" \'foo bar\' 'foo\\\\bar' -DFOO=bar\\(\\) "
       "foo\"bar\"baz C:\\\\src\\\\foo.cpp \"C:\\src\\foo.cpp\"";
   const char *const Output[] = {
@@ -193,7 +193,7 @@ TEST(CommandLineTest, TokenizeGNUCommandLine) {
 }
 
 TEST(CommandLineTest, TokenizeWindowsCommandLine) {
-  const char *Input = "a\\b c\\\\d e\\\\\"f g\" h\\\"i j\\\\\\\"k \"lmn\" o pqr "
+  const char Input[] = "a\\b c\\\\d e\\\\\"f g\" h\\\"i j\\\\\\\"k \"lmn\" o pqr "
                       "\"st \\\"u\" \\v";
   const char *const Output[] = { "a\\b", "c\\\\d", "e\\f g", "h\"i", "j\\\"k",
                                  "lmn", "o", "pqr", "st \"u", "\\v" };
@@ -299,7 +299,7 @@ TEST(CommandLineTest, SetValueInSubcategories) {
   EXPECT_FALSE(SC1Opt);
   EXPECT_FALSE(SC2Opt);
   const char *args[] = {"prog", "-top-level"};
-  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, StringRef(), true));
   EXPECT_TRUE(TopLevelOpt);
   EXPECT_FALSE(SC1Opt);
   EXPECT_FALSE(SC2Opt);
@@ -311,7 +311,7 @@ TEST(CommandLineTest, SetValueInSubcategories) {
   EXPECT_FALSE(SC1Opt);
   EXPECT_FALSE(SC2Opt);
   const char *args2[] = {"prog", "sc1", "-sc1"};
-  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args2, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args2, StringRef(), true));
   EXPECT_FALSE(TopLevelOpt);
   EXPECT_TRUE(SC1Opt);
   EXPECT_FALSE(SC2Opt);
@@ -323,7 +323,7 @@ TEST(CommandLineTest, SetValueInSubcategories) {
   EXPECT_FALSE(SC1Opt);
   EXPECT_FALSE(SC2Opt);
   const char *args3[] = {"prog", "sc2", "-sc2"};
-  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args3, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args3, StringRef(), true));
   EXPECT_FALSE(TopLevelOpt);
   EXPECT_FALSE(SC1Opt);
   EXPECT_TRUE(SC2Opt);
@@ -339,7 +339,7 @@ TEST(CommandLineTest, LookupFailsInWrongSubCommand) {
   StackOption<bool> SC2Opt("sc2", cl::sub(SC2), cl::init(false));
 
   const char *args[] = {"prog", "sc1", "-sc2"};
-  EXPECT_FALSE(cl::ParseCommandLineOptions(3, args, nullptr, true));
+  EXPECT_FALSE(cl::ParseCommandLineOptions(3, args, StringRef(), true));
 }
 
 TEST(CommandLineTest, AddToAllSubCommands) {
@@ -355,21 +355,21 @@ TEST(CommandLineTest, AddToAllSubCommands) {
   const char *args3[] = {"prog", "sc2", "-everywhere"};
 
   EXPECT_FALSE(AllOpt);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, StringRef(), true));
   EXPECT_TRUE(AllOpt);
 
   AllOpt = false;
 
   cl::ResetAllOptionOccurrences();
   EXPECT_FALSE(AllOpt);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args2, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args2, StringRef(), true));
   EXPECT_TRUE(AllOpt);
 
   AllOpt = false;
 
   cl::ResetAllOptionOccurrences();
   EXPECT_FALSE(AllOpt);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args3, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args3, StringRef(), true));
   EXPECT_TRUE(AllOpt);
 }
 
@@ -382,14 +382,14 @@ TEST(CommandLineTest, ReparseCommandLineOptions) {
   const char *args[] = {"prog", "-top-level"};
 
   EXPECT_FALSE(TopLevelOpt);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, StringRef(), true));
   EXPECT_TRUE(TopLevelOpt);
 
   TopLevelOpt = false;
 
   cl::ResetAllOptionOccurrences();
   EXPECT_FALSE(TopLevelOpt);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, StringRef(), true));
   EXPECT_TRUE(TopLevelOpt);
 }
 
@@ -403,13 +403,13 @@ TEST(CommandLineTest, RemoveFromRegularSubCommand) {
   const char *args[] = {"prog", "sc", "-remove-option"};
 
   EXPECT_FALSE(RemoveOption);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args, StringRef(), true));
   EXPECT_TRUE(RemoveOption);
 
   RemoveOption.removeArgument();
 
   cl::ResetAllOptionOccurrences();
-  EXPECT_FALSE(cl::ParseCommandLineOptions(3, args, nullptr, true));
+  EXPECT_FALSE(cl::ParseCommandLineOptions(3, args, StringRef(), true));
 }
 
 TEST(CommandLineTest, RemoveFromTopLevelSubCommand) {
@@ -423,13 +423,13 @@ TEST(CommandLineTest, RemoveFromTopLevelSubCommand) {
   const char *args[] = {"prog", "-top-level-remove"};
 
   EXPECT_FALSE(TopLevelRemove);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args, StringRef(), true));
   EXPECT_TRUE(TopLevelRemove);
 
   TopLevelRemove.removeArgument();
 
   cl::ResetAllOptionOccurrences();
-  EXPECT_FALSE(cl::ParseCommandLineOptions(2, args, nullptr, true));
+  EXPECT_FALSE(cl::ParseCommandLineOptions(2, args, StringRef(), true));
 }
 
 TEST(CommandLineTest, RemoveFromAllSubCommands) {
@@ -448,32 +448,32 @@ TEST(CommandLineTest, RemoveFromAllSubCommands) {
 
   // It should work for all subcommands including the top-level.
   EXPECT_FALSE(RemoveOption);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args0, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(2, args0, StringRef(), true));
   EXPECT_TRUE(RemoveOption);
 
   RemoveOption = false;
 
   cl::ResetAllOptionOccurrences();
   EXPECT_FALSE(RemoveOption);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args1, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args1, StringRef(), true));
   EXPECT_TRUE(RemoveOption);
 
   RemoveOption = false;
 
   cl::ResetAllOptionOccurrences();
   EXPECT_FALSE(RemoveOption);
-  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args2, nullptr, true));
+  EXPECT_TRUE(cl::ParseCommandLineOptions(3, args2, StringRef(), true));
   EXPECT_TRUE(RemoveOption);
 
   RemoveOption.removeArgument();
 
   // It should not work for any subcommands including the top-level.
   cl::ResetAllOptionOccurrences();
-  EXPECT_FALSE(cl::ParseCommandLineOptions(2, args0, nullptr, true));
+  EXPECT_FALSE(cl::ParseCommandLineOptions(2, args0, StringRef(), true));
   cl::ResetAllOptionOccurrences();
-  EXPECT_FALSE(cl::ParseCommandLineOptions(3, args1, nullptr, true));
+  EXPECT_FALSE(cl::ParseCommandLineOptions(3, args1, StringRef(), true));
   cl::ResetAllOptionOccurrences();
-  EXPECT_FALSE(cl::ParseCommandLineOptions(3, args2, nullptr, true));
+  EXPECT_FALSE(cl::ParseCommandLineOptions(3, args2, StringRef(), true));
 }
 
 }  // anonymous namespace