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 //===- llvm/Support/CommandLine.h - Command line handler --------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This class implements a command line argument processor that is useful when
 // creating a tool.  It provides a simple, minimalistic interface that is easily
 // extensible and supports nonlocal (library) command line options.
 //
 // Note that rather than trying to figure out what this code does, you should
 // read the library documentation located in docs/CommandLine.html or looks at
 // the many example usages in tools/*/*.cpp
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_SUPPORT_COMMANDLINE_H
 #define LLVM_SUPPORT_COMMANDLINE_H
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/StringSaver.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cassert>
 #include <climits>
 #include <cstddef>
 #include <functional>
 #include <initializer_list>
 #include <string>
 #include <type_traits>
 #include <vector>
 
 namespace llvm {
 
 namespace vfs {
 class FileSystem;
 }
 
 class StringSaver;
 
 /// This namespace contains all of the command line option processing machinery.
 /// It is intentionally a short name to make qualified usage concise.
 namespace cl {
 
 //===----------------------------------------------------------------------===//
 // Command line option processing entry point.
 //
 // Returns true on success. Otherwise, this will print the error message to
 // stderr and exit if \p Errs is not set (nullptr by default), or print the
 // error message to \p Errs and return false if \p Errs is provided.
 //
 // If EnvVar is not nullptr, command-line options are also parsed from the
 // environment variable named by EnvVar.  Precedence is given to occurrences
 // from argv.  This precedence is currently implemented by parsing argv after
 // the environment variable, so it is only implemented correctly for options
 // that give precedence to later occurrences.  If your program supports options
 // that give precedence to earlier occurrences, you will need to extend this
 // function to support it correctly.
 bool ParseCommandLineOptions(int argc, const char *const *argv,
                              StringRef Overview = "",
                              raw_ostream *Errs = nullptr,
                              const char *EnvVar = nullptr,
                              bool LongOptionsUseDoubleDash = false);
 
 // Function pointer type for printing version information.
 using VersionPrinterTy = std::function<void(raw_ostream &)>;
 
 ///===---------------------------------------------------------------------===//
 /// Override the default (LLVM specific) version printer used to print out the
 /// version when --version is given on the command line. This allows other
 /// systems using the CommandLine utilities to print their own version string.
 void SetVersionPrinter(VersionPrinterTy func);
 
 ///===---------------------------------------------------------------------===//
 /// Add an extra printer to use in addition to the default one. This can be
 /// called multiple times, and each time it adds a new function to the list
 /// which will be called after the basic LLVM version printing is complete.
 /// Each can then add additional information specific to the tool.
 void AddExtraVersionPrinter(VersionPrinterTy func);
 
 // Print option values.
 // With -print-options print the difference between option values and defaults.
 // With -print-all-options print all option values.
 // (Currently not perfect, but best-effort.)
 void PrintOptionValues();
 
 // Forward declaration - AddLiteralOption needs to be up here to make gcc happy.
 class Option;
 
 /// Adds a new option for parsing and provides the option it refers to.
 ///
 /// \param O pointer to the option
 /// \param Name the string name for the option to handle during parsing
 ///
 /// 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, StringRef Name);
 
 //===----------------------------------------------------------------------===//
 // Flags permitted to be passed to command line arguments
 //
 
 enum NumOccurrencesFlag { // Flags for the number of occurrences allowed
   Optional = 0x00,        // Zero or One occurrence
   ZeroOrMore = 0x01,      // Zero or more occurrences allowed
   Required = 0x02,        // One occurrence required
   OneOrMore = 0x03,       // One or more occurrences required
 
   // Indicates that this option is fed anything that follows the last positional
   // argument required by the application (it is an error if there are zero
   // positional arguments, and a ConsumeAfter option is used).
   // Thus, for example, all arguments to LLI are processed until a filename is
   // found.  Once a filename is found, all of the succeeding arguments are
   // passed, unprocessed, to the ConsumeAfter option.
   //
   ConsumeAfter = 0x04
 };
 
 enum ValueExpected { // Is a value required for the option?
   // zero reserved for the unspecified value
   ValueOptional = 0x01,  // The value can appear... or not
   ValueRequired = 0x02,  // The value is required to appear!
   ValueDisallowed = 0x03 // A value may not be specified (for flags)
 };
 
 enum OptionHidden {   // Control whether -help shows this option
   NotHidden = 0x00,   // Option included in -help & -help-hidden
   Hidden = 0x01,      // -help doesn't, but -help-hidden does
   ReallyHidden = 0x02 // Neither -help nor -help-hidden show this arg
 };
 
 // This controls special features that the option might have that cause it to be
 // parsed differently...
 //
 // Prefix - This option allows arguments that are otherwise unrecognized to be
 // matched by options that are a prefix of the actual value.  This is useful for
 // cases like a linker, where options are typically of the form '-lfoo' or
 // '-L../../include' where -l or -L are the actual flags.  When prefix is
 // enabled, and used, the value for the flag comes from the suffix of the
 // argument.
 //
 // AlwaysPrefix - Only allow the behavior enabled by the Prefix flag and reject
 // the Option=Value form.
 //
 
 enum FormattingFlags {
   NormalFormatting = 0x00, // Nothing special
   Positional = 0x01,       // Is a positional argument, no '-' required
   Prefix = 0x02,           // Can this option directly prefix its value?
   AlwaysPrefix = 0x03      // Can this option only directly prefix its value?
 };
 
 enum MiscFlags {             // Miscellaneous flags to adjust argument
   CommaSeparated = 0x01,     // Should this cl::list split between commas?
   PositionalEatsArgs = 0x02, // Should this positional cl::list eat -args?
   Sink = 0x04,               // Should this cl::list eat all unknown options?
 
   // Can this option group with other options?
   // If this is enabled, multiple letter options are allowed to bunch together
   // with only a single hyphen for the whole group.  This allows emulation
   // of the behavior that ls uses for example: ls -la === ls -l -a
   Grouping = 0x08,
 
   // Default option
   DefaultOption = 0x10
 };
 
 //===----------------------------------------------------------------------===//
 //
 class OptionCategory {
 private:
   StringRef const Name;
   StringRef const Description;
 
   void registerCategory();
 
 public:
   OptionCategory(StringRef const Name,
                  StringRef const Description = "")
       : Name(Name), Description(Description) {
     registerCategory();
   }
 
   StringRef getName() const { return Name; }
   StringRef getDescription() const { return Description; }
 };
 
 // The general Option Category (used as default category).
 OptionCategory &getGeneralCategory();
 
 //===----------------------------------------------------------------------===//
 //
 class SubCommand {
 private:
   StringRef Name;
   StringRef Description;
 
 protected:
   void registerSubCommand();
   void unregisterSubCommand();
 
 public:
   SubCommand(StringRef Name, StringRef Description = "")
       : Name(Name), Description(Description) {
         registerSubCommand();
   }
   SubCommand() = default;
 
   // Get the special subcommand representing no subcommand.
   static SubCommand &getTopLevel();
 
   // Get the special subcommand that can be used to put an option into all
   // subcommands.
   static SubCommand &getAll();
 
   void reset();
 
   explicit operator bool() const;
 
   StringRef getName() const { return Name; }
   StringRef getDescription() const { return Description; }
 
   SmallVector<Option *, 4> PositionalOpts;
   SmallVector<Option *, 4> SinkOpts;
   StringMap<Option *> OptionsMap;
 
   Option *ConsumeAfterOpt = nullptr; // The ConsumeAfter option if it exists.
 };
 
 class SubCommandGroup {
   SmallVector<SubCommand *, 4> Subs;
 
 public:
   SubCommandGroup(std::initializer_list<SubCommand *> IL) : Subs(IL) {}
 
   ArrayRef<SubCommand *> getSubCommands() const { return Subs; }
 };
 
 //===----------------------------------------------------------------------===//
 //
 class Option {
   friend class alias;
 
   // Overriden by subclasses to handle the value passed into an argument. Should
   // return true if there was an error processing the argument and the program
   // should exit.
   //
   virtual bool handleOccurrence(unsigned pos, StringRef ArgName,
                                 StringRef Arg) = 0;
 
   virtual enum ValueExpected getValueExpectedFlagDefault() const {
     return ValueOptional;
   }
 
   // Out of line virtual function to provide home for the class.
   virtual void anchor();
 
   uint16_t NumOccurrences; // The number of times specified
   // Occurrences, HiddenFlag, and Formatting are all enum types but to avoid
   // problems with signed enums in bitfields.
   uint16_t Occurrences : 3; // enum NumOccurrencesFlag
   // not using the enum type for 'Value' because zero is an implementation
   // detail representing the non-value
   uint16_t Value : 2;
   uint16_t HiddenFlag : 2; // enum OptionHidden
   uint16_t Formatting : 2; // enum FormattingFlags
   uint16_t Misc : 5;
   uint16_t FullyInitialized : 1; // Has addArgument been called?
   uint16_t Position;             // Position of last occurrence of the option
   uint16_t AdditionalVals;       // Greater than 0 for multi-valued option.
 
 public:
   StringRef ArgStr;   // The argument string itself (ex: "help", "o")
   StringRef HelpStr;  // The descriptive text message for -help
   StringRef ValueStr; // String describing what the value of this option is
   SmallVector<OptionCategory *, 1>
       Categories;                    // The Categories this option belongs to
   SmallPtrSet<SubCommand *, 1> Subs; // The subcommands this option belongs to.
 
   inline enum NumOccurrencesFlag getNumOccurrencesFlag() const {
     return (enum NumOccurrencesFlag)Occurrences;
   }
 
   inline enum ValueExpected getValueExpectedFlag() const {
     return Value ? ((enum ValueExpected)Value) : getValueExpectedFlagDefault();
   }
 
   inline enum OptionHidden getOptionHiddenFlag() const {
     return (enum OptionHidden)HiddenFlag;
   }
 
   inline enum FormattingFlags getFormattingFlag() const {
     return (enum FormattingFlags)Formatting;
   }
 
   inline unsigned getMiscFlags() const { return Misc; }
   inline unsigned getPosition() const { return Position; }
   inline unsigned getNumAdditionalVals() const { return AdditionalVals; }
 
   // Return true if the argstr != ""
   bool hasArgStr() const { return !ArgStr.empty(); }
   bool isPositional() const { return getFormattingFlag() == cl::Positional; }
   bool isSink() const { return getMiscFlags() & cl::Sink; }
   bool isDefaultOption() const { return getMiscFlags() & cl::DefaultOption; }
 
   bool isConsumeAfter() const {
     return getNumOccurrencesFlag() == cl::ConsumeAfter;
   }
 
   //-------------------------------------------------------------------------===
   // Accessor functions set by OptionModifiers
   //
   void setArgStr(StringRef S);
   void setDescription(StringRef S) { HelpStr = S; }
   void setValueStr(StringRef S) { ValueStr = S; }
   void setNumOccurrencesFlag(enum NumOccurrencesFlag Val) { Occurrences = Val; }
   void setValueExpectedFlag(enum ValueExpected Val) { Value = Val; }
   void setHiddenFlag(enum OptionHidden Val) { HiddenFlag = Val; }
   void setFormattingFlag(enum FormattingFlags V) { Formatting = V; }
   void setMiscFlag(enum MiscFlags M) { Misc |= M; }
   void setPosition(unsigned pos) { Position = pos; }
   void addCategory(OptionCategory &C);
   void addSubCommand(SubCommand &S) { Subs.insert(&S); }
 
 protected:
   explicit Option(enum NumOccurrencesFlag OccurrencesFlag,
                   enum OptionHidden Hidden)
       : NumOccurrences(0), Occurrences(OccurrencesFlag), Value(0),
         HiddenFlag(Hidden), Formatting(NormalFormatting), Misc(0),
         FullyInitialized(false), Position(0), AdditionalVals(0) {
     Categories.push_back(&getGeneralCategory());
   }
 
   inline void setNumAdditionalVals(unsigned n) { AdditionalVals = n; }
 
 public:
   virtual ~Option() = default;
 
   // Register this argument with the commandline system.
   //
   void addArgument();
 
   /// Unregisters this option from the CommandLine system.
   ///
   /// This option must have been the last option registered.
   /// For testing purposes only.
   void removeArgument();
 
   // Return the width of the option tag for printing...
   virtual size_t getOptionWidth() const = 0;
 
   // Print out information about this option. The to-be-maintained width is
   // specified.
   //
   virtual void printOptionInfo(size_t GlobalWidth) const = 0;
 
   virtual void printOptionValue(size_t GlobalWidth, bool Force) const = 0;
 
   virtual void setDefault() = 0;
 
   // Prints the help string for an option.
   //
   // This maintains the Indent for multi-line descriptions.
   // FirstLineIndentedBy is the count of chars of the first line
   //      i.e. the one containing the --<option name>.
   static void printHelpStr(StringRef HelpStr, size_t Indent,
                            size_t FirstLineIndentedBy);
 
   // Prints the help string for an enum value.
   //
   // This maintains the Indent for multi-line descriptions.
   // FirstLineIndentedBy is the count of chars of the first line
   //      i.e. the one containing the =<value>.
   static void printEnumValHelpStr(StringRef HelpStr, size_t Indent,
                                   size_t FirstLineIndentedBy);
 
   virtual void getExtraOptionNames(SmallVectorImpl<StringRef> &) {}
 
   // Wrapper around handleOccurrence that enforces Flags.
   //
   virtual bool addOccurrence(unsigned pos, StringRef ArgName, StringRef Value,
                              bool MultiArg = false);
 
   // Prints option name followed by message.  Always returns true.
   bool error(const Twine &Message, StringRef ArgName = StringRef(), raw_ostream &Errs = llvm::errs());
   bool error(const Twine &Message, raw_ostream &Errs) {
     return error(Message, StringRef(), Errs);
   }
 
   inline int getNumOccurrences() const { return NumOccurrences; }
   void reset();
 };
 
 //===----------------------------------------------------------------------===//
 // Command line option modifiers that can be used to modify the behavior of
 // command line option parsers...
 //
 
 // Modifier to set the description shown in the -help output...
 struct desc {
   StringRef Desc;
 
   desc(StringRef Str) : Desc(Str) {}
 
   void apply(Option &O) const { O.setDescription(Desc); }
 };
 
 // Modifier to set the value description shown in the -help output...
 struct value_desc {
   StringRef Desc;
 
   value_desc(StringRef Str) : Desc(Str) {}
 
   void apply(Option &O) const { O.setValueStr(Desc); }
 };
 
 // Specify a default (initial) value for the command line argument, if the
 // default constructor for the argument type does not give you what you want.
 // This is only valid on "opt" arguments, not on "list" arguments.
 template <class Ty> struct initializer {
   const Ty &Init;
   initializer(const Ty &Val) : Init(Val) {}
 
   template <class Opt> void apply(Opt &O) const { O.setInitialValue(Init); }
 };
 
 template <class Ty> struct list_initializer {
   ArrayRef<Ty> Inits;
   list_initializer(ArrayRef<Ty> Vals) : Inits(Vals) {}
 
   template <class Opt> void apply(Opt &O) const { O.setInitialValues(Inits); }
 };
 
 template <class Ty> initializer<Ty> init(const Ty &Val) {
   return initializer<Ty>(Val);
 }
 
 template <class Ty>
 list_initializer<Ty> list_init(ArrayRef<Ty> Vals) {
   return list_initializer<Ty>(Vals);
 }
 
 // Allow the user to specify which external variable they want to store the
 // results of the command line argument processing into, if they don't want to
 // store it in the option itself.
 template <class Ty> struct LocationClass {
   Ty &Loc;
 
   LocationClass(Ty &L) : Loc(L) {}
 
   template <class Opt> void apply(Opt &O) const { O.setLocation(O, Loc); }
 };
 
 template <class Ty> LocationClass<Ty> location(Ty &L) {
   return LocationClass<Ty>(L);
 }
 
 // Specify the Option category for the command line argument to belong to.
 struct cat {
   OptionCategory &Category;
 
   cat(OptionCategory &c) : Category(c) {}
 
   template <class Opt> void apply(Opt &O) const { O.addCategory(Category); }
 };
 
 // Specify the subcommand that this option belongs to.
 struct sub {
   SubCommand *Sub = nullptr;
   SubCommandGroup *Group = nullptr;
 
   sub(SubCommand &S) : Sub(&S) {}
   sub(SubCommandGroup &G) : Group(&G) {}
 
   template <class Opt> void apply(Opt &O) const {
     if (Sub)
       O.addSubCommand(*Sub);
     else if (Group)
       for (SubCommand *SC : Group->getSubCommands())
         O.addSubCommand(*SC);
   }
 };
 
 // Specify a callback function to be called when an option is seen.
 // Can be used to set other options automatically.
 template <typename R, typename Ty> struct cb {
   std::function<R(Ty)> CB;
 
   cb(std::function<R(Ty)> CB) : CB(CB) {}
 
   template <typename Opt> void apply(Opt &O) const { O.setCallback(CB); }
 };
 
 namespace detail {
 template <typename F>
 struct callback_traits : public callback_traits<decltype(&F::operator())> {};
 
 template <typename R, typename C, typename... Args>
 struct callback_traits<R (C::*)(Args...) const> {
   using result_type = R;
   using arg_type = std::tuple_element_t<0, std::tuple<Args...>>;
   static_assert(sizeof...(Args) == 1, "callback function must have one and only one parameter");
   static_assert(std::is_same_v<result_type, void>,
                 "callback return type must be void");
   static_assert(std::is_lvalue_reference_v<arg_type> &&
                     std::is_const_v<std::remove_reference_t<arg_type>>,
                 "callback arg_type must be a const lvalue reference");
 };
 } // namespace detail
 
 template <typename F>
 cb<typename detail::callback_traits<F>::result_type,
    typename detail::callback_traits<F>::arg_type>
 callback(F CB) {
   using result_type = typename detail::callback_traits<F>::result_type;
   using arg_type = typename detail::callback_traits<F>::arg_type;
   return cb<result_type, arg_type>(CB);
 }
 
 //===----------------------------------------------------------------------===//
 
 // Support value comparison outside the template.
 struct GenericOptionValue {
   virtual bool compare(const GenericOptionValue &V) const = 0;
 
 protected:
   GenericOptionValue() = default;
   GenericOptionValue(const GenericOptionValue&) = default;
   GenericOptionValue &operator=(const GenericOptionValue &) = default;
   ~GenericOptionValue() = default;
 
 private:
   virtual void anchor();
 };
 
 template <class DataType> struct OptionValue;
 
 // The default value safely does nothing. Option value printing is only
 // best-effort.
 template <class DataType, bool isClass>
 struct OptionValueBase : public GenericOptionValue {
   // Temporary storage for argument passing.
   using WrapperType = OptionValue<DataType>;
 
   bool hasValue() const { return false; }
 
   const DataType &getValue() const { llvm_unreachable("no default value"); }
 
   // Some options may take their value from a different data type.
   template <class DT> void setValue(const DT & /*V*/) {}
 
   // Returns whether this instance matches the argument.
   bool compare(const DataType & /*V*/) const { return false; }
 
   bool compare(const GenericOptionValue & /*V*/) const override {
     return false;
   }
 
 protected:
   ~OptionValueBase() = default;
 };
 
 // Simple copy of the option value.
 template <class DataType> class OptionValueCopy : public GenericOptionValue {
   DataType Value;
   bool Valid = false;
 
 protected:
   OptionValueCopy(const OptionValueCopy&) = default;
   OptionValueCopy &operator=(const OptionValueCopy &) = default;
   ~OptionValueCopy() = default;
 
 public:
   OptionValueCopy() = default;
 
   bool hasValue() const { return Valid; }
 
   const DataType &getValue() const {
     assert(Valid && "invalid option value");
     return Value;
   }
 
   void setValue(const DataType &V) {
     Valid = true;
     Value = V;
   }
 
   // Returns whether this instance matches V.
   bool compare(const DataType &V) const { return Valid && (Value == V); }
 
   bool compare(const GenericOptionValue &V) const override {
     const OptionValueCopy<DataType> &VC =
         static_cast<const OptionValueCopy<DataType> &>(V);
     if (!VC.hasValue())
       return false;
     return compare(VC.getValue());
   }
 };
 
 // Non-class option values.
 template <class DataType>
 struct OptionValueBase<DataType, false> : OptionValueCopy<DataType> {
   using WrapperType = DataType;
 
 protected:
   OptionValueBase() = default;
   OptionValueBase(const OptionValueBase&) = default;
   OptionValueBase &operator=(const OptionValueBase &) = default;
   ~OptionValueBase() = default;
 };
 
 // Top-level option class.
 template <class DataType>
 struct OptionValue final
     : OptionValueBase<DataType, std::is_class_v<DataType>> {
   OptionValue() = default;
 
   OptionValue(const DataType &V) { this->setValue(V); }
 
   // Some options may take their value from a different data type.
   template <class DT> OptionValue<DataType> &operator=(const DT &V) {
     this->setValue(V);
     return *this;
   }
 };
 
 // Other safe-to-copy-by-value common option types.
 enum boolOrDefault { BOU_UNSET, BOU_TRUE, BOU_FALSE };
 template <>
 struct OptionValue<cl::boolOrDefault> final
     : OptionValueCopy<cl::boolOrDefault> {
   using WrapperType = cl::boolOrDefault;
 
   OptionValue() = default;
 
   OptionValue(const cl::boolOrDefault &V) { this->setValue(V); }
 
   OptionValue<cl::boolOrDefault> &operator=(const cl::boolOrDefault &V) {
     setValue(V);
     return *this;
   }
 
 private:
   void anchor() override;
 };
 
 template <>
 struct OptionValue<std::string> final : OptionValueCopy<std::string> {
   using WrapperType = StringRef;
 
   OptionValue() = default;
 
   OptionValue(const std::string &V) { this->setValue(V); }
 
   OptionValue<std::string> &operator=(const std::string &V) {
     setValue(V);
     return *this;
   }
 
 private:
   void anchor() override;
 };
 
 //===----------------------------------------------------------------------===//
 // Enum valued command line option
 //
 
 // This represents a single enum value, using "int" as the underlying type.
 struct OptionEnumValue {
   StringRef Name;
   int Value;
   StringRef Description;
 };
 
 #define clEnumVal(ENUMVAL, DESC)                                               \
   llvm::cl::OptionEnumValue { #ENUMVAL, int(ENUMVAL), DESC }
 #define clEnumValN(ENUMVAL, FLAGNAME, DESC)                                    \
   llvm::cl::OptionEnumValue { FLAGNAME, int(ENUMVAL), DESC }
 
 // For custom data types, allow specifying a group of values together as the
 // values that go into the mapping that the option handler uses.
 //
 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<OptionEnumValue, 4> Values;
 
 public:
   ValuesClass(std::initializer_list<OptionEnumValue> Options)
       : Values(Options) {}
 
   template <class Opt> void apply(Opt &O) const {
     for (const auto &Value : Values)
       O.getParser().addLiteralOption(Value.Name, Value.Value,
                                      Value.Description);
   }
 };
 
 /// Helper to build a ValuesClass by forwarding a variable number of arguments
 /// as an initializer list to the ValuesClass constructor.
 template <typename... OptsTy> ValuesClass values(OptsTy... Options) {
   return ValuesClass({Options...});
 }
 
 //===----------------------------------------------------------------------===//
 // Parameterizable parser for different data types. By default, known data types
 // (string, int, bool) have specialized parsers, that do what you would expect.
 // The default parser, used for data types that are not built-in, uses a mapping
 // table to map specific options to values, which is used, among other things,
 // to handle enum types.
 
 //--------------------------------------------------
 // This class holds all the non-generic code that we do not need replicated for
 // every instance of the generic parser.  This also allows us to put stuff into
 // CommandLine.cpp
 //
 class generic_parser_base {
 protected:
   class GenericOptionInfo {
   public:
     GenericOptionInfo(StringRef name, StringRef helpStr)
         : Name(name), HelpStr(helpStr) {}
     StringRef Name;
     StringRef HelpStr;
   };
 
 public:
   generic_parser_base(Option &O) : Owner(O) {}
 
   virtual ~generic_parser_base() = default;
   // Base class should have virtual-destructor
 
   // Virtual function implemented by generic subclass to indicate how many
   // entries are in Values.
   //
   virtual unsigned getNumOptions() const = 0;
 
   // Return option name N.
   virtual StringRef getOption(unsigned N) const = 0;
 
   // Return description N
   virtual StringRef getDescription(unsigned N) const = 0;
 
   // Return the width of the option tag for printing...
   virtual size_t getOptionWidth(const Option &O) const;
 
   virtual const GenericOptionValue &getOptionValue(unsigned N) const = 0;
 
   // Print out information about this option. The to-be-maintained width is
   // specified.
   //
   virtual void printOptionInfo(const Option &O, size_t GlobalWidth) const;
 
   void printGenericOptionDiff(const Option &O, const GenericOptionValue &V,
                               const GenericOptionValue &Default,
                               size_t GlobalWidth) const;
 
   // Print the value of an option and it's default.
   //
   // Template definition ensures that the option and default have the same
   // DataType (via the same AnyOptionValue).
   template <class AnyOptionValue>
   void printOptionDiff(const Option &O, const AnyOptionValue &V,
                        const AnyOptionValue &Default,
                        size_t GlobalWidth) const {
     printGenericOptionDiff(O, V, Default, GlobalWidth);
   }
 
   void initialize() {}
 
   void getExtraOptionNames(SmallVectorImpl<StringRef> &OptionNames) {
     // If there has been no argstr specified, that means that we need to add an
     // argument for every possible option.  This ensures that our options are
     // vectored to us.
     if (!Owner.hasArgStr())
       for (unsigned i = 0, e = getNumOptions(); i != e; ++i)
         OptionNames.push_back(getOption(i));
   }
 
   enum ValueExpected getValueExpectedFlagDefault() const {
     // If there is an ArgStr specified, then we are of the form:
     //
     //    -opt=O2   or   -opt O2  or  -optO2
     //
     // In which case, the value is required.  Otherwise if an arg str has not
     // been specified, we are of the form:
     //
     //    -O2 or O2 or -la (where -l and -a are separate options)
     //
     // If this is the case, we cannot allow a value.
     //
     if (Owner.hasArgStr())
       return ValueRequired;
     else
       return ValueDisallowed;
   }
 
   // Return the option number corresponding to the specified
   // argument string.  If the option is not found, getNumOptions() is returned.
   //
   unsigned findOption(StringRef Name);
 
 protected:
   Option &Owner;
 };
 
 // Default parser implementation - This implementation depends on having a
 // mapping of recognized options to values of some sort.  In addition to this,
 // each entry in the mapping also tracks a help message that is printed with the
 // command line option for -help.  Because this is a simple mapping parser, the
 // data type can be any unsupported type.
 //
 template <class DataType> class parser : public generic_parser_base {
 protected:
   class OptionInfo : public GenericOptionInfo {
   public:
     OptionInfo(StringRef name, DataType v, StringRef helpStr)
         : GenericOptionInfo(name, helpStr), V(v) {}
 
     OptionValue<DataType> V;
   };
   SmallVector<OptionInfo, 8> Values;
 
 public:
   parser(Option &O) : generic_parser_base(O) {}
 
   using parser_data_type = DataType;
 
   // Implement virtual functions needed by generic_parser_base
   unsigned getNumOptions() const override { return unsigned(Values.size()); }
   StringRef getOption(unsigned N) const override { return Values[N].Name; }
   StringRef getDescription(unsigned N) const override {
     return Values[N].HelpStr;
   }
 
   // Return the value of option name N.
   const GenericOptionValue &getOptionValue(unsigned N) const override {
     return Values[N].V;
   }
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, DataType &V) {
     StringRef ArgVal;
     if (Owner.hasArgStr())
       ArgVal = Arg;
     else
       ArgVal = ArgName;
 
     for (size_t i = 0, e = Values.size(); i != e; ++i)
       if (Values[i].Name == ArgVal) {
         V = Values[i].V.getValue();
         return false;
       }
 
     return O.error("Cannot find option named '" + ArgVal + "'!");
   }
 
   /// Add an entry to the mapping table.
   ///
   template <class DT>
   void addLiteralOption(StringRef Name, const DT &V, StringRef HelpStr) {
 #ifndef NDEBUG
     if (findOption(Name) != Values.size())
       report_fatal_error("Option '" + Name + "' already exists!");
 #endif
     OptionInfo X(Name, static_cast<DataType>(V), HelpStr);
     Values.push_back(X);
     AddLiteralOption(Owner, Name);
   }
 
   /// Remove the specified option.
   ///
   void removeLiteralOption(StringRef Name) {
     unsigned N = findOption(Name);
     assert(N != Values.size() && "Option not found!");
     Values.erase(Values.begin() + N);
   }
 };
 
 //--------------------------------------------------
 // Super class of parsers to provide boilerplate code
 //
 class basic_parser_impl { // non-template implementation of basic_parser<t>
 public:
   basic_parser_impl(Option &) {}
 
   virtual ~basic_parser_impl() = default;
 
   enum ValueExpected getValueExpectedFlagDefault() const {
     return ValueRequired;
   }
 
   void getExtraOptionNames(SmallVectorImpl<StringRef> &) {}
 
   void initialize() {}
 
   // Return the width of the option tag for printing...
   size_t getOptionWidth(const Option &O) const;
 
   // Print out information about this option. The to-be-maintained width is
   // specified.
   //
   void printOptionInfo(const Option &O, size_t GlobalWidth) const;
 
   // Print a placeholder for options that don't yet support printOptionDiff().
   void printOptionNoValue(const Option &O, size_t GlobalWidth) const;
 
   // Overload in subclass to provide a better default value.
   virtual StringRef getValueName() const { return "value"; }
 
   // An out-of-line virtual method to provide a 'home' for this class.
   virtual void anchor();
 
 protected:
   // A helper for basic_parser::printOptionDiff.
   void printOptionName(const Option &O, size_t GlobalWidth) const;
 };
 
 // The real basic parser is just a template wrapper that provides a typedef for
 // the provided data type.
 //
 template <class DataType> class basic_parser : public basic_parser_impl {
 public:
   using parser_data_type = DataType;
   using OptVal = OptionValue<DataType>;
 
   basic_parser(Option &O) : basic_parser_impl(O) {}
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<bool>;
 
 template <> class parser<bool> : public basic_parser<bool> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, bool &Val);
 
   void initialize() {}
 
   enum ValueExpected getValueExpectedFlagDefault() const {
     return ValueOptional;
   }
 
   // Do not print =<value> at all.
   StringRef getValueName() const override { return StringRef(); }
 
   void printOptionDiff(const Option &O, bool V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<boolOrDefault>;
 
 template <> class parser<boolOrDefault> : public basic_parser<boolOrDefault> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, boolOrDefault &Val);
 
   enum ValueExpected getValueExpectedFlagDefault() const {
     return ValueOptional;
   }
 
   // Do not print =<value> at all.
   StringRef getValueName() const override { return StringRef(); }
 
   void printOptionDiff(const Option &O, boolOrDefault V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<int>;
 
 template <> class parser<int> : public basic_parser<int> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, int &Val);
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "int"; }
 
   void printOptionDiff(const Option &O, int V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<long>;
 
 template <> class parser<long> final : public basic_parser<long> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, long &Val);
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "long"; }
 
   void printOptionDiff(const Option &O, long V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<long long>;
 
 template <> class parser<long long> : public basic_parser<long long> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, long long &Val);
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "long"; }
 
   void printOptionDiff(const Option &O, long long V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<unsigned>;
 
 template <> class parser<unsigned> : public basic_parser<unsigned> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, unsigned &Val);
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "uint"; }
 
   void printOptionDiff(const Option &O, unsigned V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<unsigned long>;
 
 template <>
 class parser<unsigned long> final : public basic_parser<unsigned long> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, unsigned long &Val);
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "ulong"; }
 
   void printOptionDiff(const Option &O, unsigned long V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<unsigned long long>;
 
 template <>
 class parser<unsigned long long> : public basic_parser<unsigned long long> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg,
              unsigned long long &Val);
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "ulong"; }
 
   void printOptionDiff(const Option &O, unsigned long long V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<double>;
 
 template <> class parser<double> : public basic_parser<double> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, double &Val);
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "number"; }
 
   void printOptionDiff(const Option &O, double V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<float>;
 
 template <> class parser<float> : public basic_parser<float> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &O, StringRef ArgName, StringRef Arg, float &Val);
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "number"; }
 
   void printOptionDiff(const Option &O, float V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<std::string>;
 
 template <> class parser<std::string> : public basic_parser<std::string> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &, StringRef, StringRef Arg, std::string &Value) {
     Value = Arg.str();
     return false;
   }
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "string"; }
 
   void printOptionDiff(const Option &O, StringRef V, const OptVal &Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 
 extern template class basic_parser<char>;
 
 template <> class parser<char> : public basic_parser<char> {
 public:
   parser(Option &O) : basic_parser(O) {}
 
   // Return true on error.
   bool parse(Option &, StringRef, StringRef Arg, char &Value) {
     Value = Arg[0];
     return false;
   }
 
   // Overload in subclass to provide a better default value.
   StringRef getValueName() const override { return "char"; }
 
   void printOptionDiff(const Option &O, char V, OptVal Default,
                        size_t GlobalWidth) const;
 
   // An out-of-line virtual method to provide a 'home' for this class.
   void anchor() override;
 };
 
 //--------------------------------------------------
 // This collection of wrappers is the intermediary between class opt and class
 // parser to handle all the template nastiness.
 
 // This overloaded function is selected by the generic parser.
 template <class ParserClass, class DT>
 void printOptionDiff(const Option &O, const generic_parser_base &P, const DT &V,
                      const OptionValue<DT> &Default, size_t GlobalWidth) {
   OptionValue<DT> OV = V;
   P.printOptionDiff(O, OV, Default, GlobalWidth);
 }
 
 // This is instantiated for basic parsers when the parsed value has a different
 // type than the option value. e.g. HelpPrinter.
 template <class ParserDT, class ValDT> struct OptionDiffPrinter {
   void print(const Option &O, const parser<ParserDT> &P, const ValDT & /*V*/,
              const OptionValue<ValDT> & /*Default*/, size_t GlobalWidth) {
     P.printOptionNoValue(O, GlobalWidth);
   }
 };
 
 // This is instantiated for basic parsers when the parsed value has the same
 // type as the option value.
 template <class DT> struct OptionDiffPrinter<DT, DT> {
   void print(const Option &O, const parser<DT> &P, const DT &V,
              const OptionValue<DT> &Default, size_t GlobalWidth) {
     P.printOptionDiff(O, V, Default, GlobalWidth);
   }
 };
 
 // This overloaded function is selected by the basic parser, which may parse a
 // different type than the option type.
 template <class ParserClass, class ValDT>
 void printOptionDiff(
     const Option &O,
     const basic_parser<typename ParserClass::parser_data_type> &P,
     const ValDT &V, const OptionValue<ValDT> &Default, size_t GlobalWidth) {
 
   OptionDiffPrinter<typename ParserClass::parser_data_type, ValDT> printer;
   printer.print(O, static_cast<const ParserClass &>(P), V, Default,
                 GlobalWidth);
 }
 
 //===----------------------------------------------------------------------===//
 // This class is used because we must use partial specialization to handle
 // literal string arguments specially (const char* does not correctly respond to
 // the apply method). Because the syntax to use this is a pain, we have the
 // 'apply' method below to handle the nastiness...
 //
 template <class Mod> struct applicator {
   template <class Opt> static void opt(const Mod &M, Opt &O) { M.apply(O); }
 };
 
 // Handle const char* as a special case...
 template <unsigned n> struct applicator<char[n]> {
   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(StringRef Str, Opt &O) {
     O.setArgStr(Str);
   }
 };
 template <> struct applicator<StringRef > {
   template <class Opt> static void opt(StringRef Str, Opt &O) {
     O.setArgStr(Str);
   }
 };
 
 template <> struct applicator<NumOccurrencesFlag> {
   static void opt(NumOccurrencesFlag N, Option &O) {
     O.setNumOccurrencesFlag(N);
   }
 };
 
 template <> struct applicator<ValueExpected> {
   static void opt(ValueExpected VE, Option &O) { O.setValueExpectedFlag(VE); }
 };
 
 template <> struct applicator<OptionHidden> {
   static void opt(OptionHidden OH, Option &O) { O.setHiddenFlag(OH); }
 };
 
 template <> struct applicator<FormattingFlags> {
   static void opt(FormattingFlags FF, Option &O) { O.setFormattingFlag(FF); }
 };
 
 template <> struct applicator<MiscFlags> {
   static void opt(MiscFlags MF, Option &O) {
     assert((MF != Grouping || O.ArgStr.size() == 1) &&
            "cl::Grouping can only apply to single character Options.");
     O.setMiscFlag(MF);
   }
 };
 
 // Apply modifiers to an option in a type safe way.
 template <class Opt, class Mod, class... Mods>
 void apply(Opt *O, const Mod &M, const Mods &... Ms) {
   applicator<Mod>::opt(M, *O);
   apply(O, Ms...);
 }
 
 template <class Opt, class Mod> void apply(Opt *O, const Mod &M) {
   applicator<Mod>::opt(M, *O);
 }
 
 //===----------------------------------------------------------------------===//
 // Default storage class definition: external storage.  This implementation
 // assumes the user will specify a variable to store the data into with the
 // cl::location(x) modifier.
 //
 template <class DataType, bool ExternalStorage, bool isClass>
 class opt_storage {
   DataType *Location = nullptr; // Where to store the object...
   OptionValue<DataType> Default;
 
   void check_location() const {
     assert(Location && "cl::location(...) not specified for a command "
                        "line option with external storage, "
                        "or cl::init specified before cl::location()!!");
   }
 
 public:
   opt_storage() = default;
 
   bool setLocation(Option &O, DataType &L) {
     if (Location)
       return O.error("cl::location(x) specified more than once!");
     Location = &L;
     Default = L;
     return false;
   }
 
   template <class T> void setValue(const T &V, bool initial = false) {
     check_location();
     *Location = V;
     if (initial)
       Default = V;
   }
 
   DataType &getValue() {
     check_location();
     return *Location;
   }
   const DataType &getValue() const {
     check_location();
     return *Location;
   }
 
   operator DataType() const { return this->getValue(); }
 
   const OptionValue<DataType> &getDefault() const { return Default; }
 };
 
 // Define how to hold a class type object, such as a string.  Since we can
 // inherit from a class, we do so.  This makes us exactly compatible with the
 // object in all cases that it is used.
 //
 template <class DataType>
 class opt_storage<DataType, false, true> : public DataType {
 public:
   OptionValue<DataType> Default;
 
   template <class T> void setValue(const T &V, bool initial = false) {
     DataType::operator=(V);
     if (initial)
       Default = V;
   }
 
   DataType &getValue() { return *this; }
   const DataType &getValue() const { return *this; }
 
   const OptionValue<DataType> &getDefault() const { return Default; }
 };
 
 // Define a partial specialization to handle things we cannot inherit from.  In
 // this case, we store an instance through containment, and overload operators
 // to get at the value.
 //
 template <class DataType> class opt_storage<DataType, false, false> {
 public:
   DataType Value;
   OptionValue<DataType> Default;
 
   // Make sure we initialize the value with the default constructor for the
   // type.
   opt_storage() : Value(DataType()), Default() {}
 
   template <class T> void setValue(const T &V, bool initial = false) {
     Value = V;
     if (initial)
       Default = V;
   }
   DataType &getValue() { return Value; }
   DataType getValue() const { return Value; }
 
   const OptionValue<DataType> &getDefault() const { return Default; }
 
   operator DataType() const { return getValue(); }
 
   // If the datatype is a pointer, support -> on it.
   DataType operator->() const { return Value; }
 };
 
 //===----------------------------------------------------------------------===//
 // A scalar command line option.
 //
 template <class DataType, bool ExternalStorage = false,
           class ParserClass = parser<DataType>>
 class opt
     : public Option,
       public opt_storage<DataType, ExternalStorage, std::is_class_v<DataType>> {
   ParserClass Parser;
 
   bool handleOccurrence(unsigned pos, StringRef ArgName,
                         StringRef Arg) override {
     typename ParserClass::parser_data_type Val =
         typename ParserClass::parser_data_type();
     if (Parser.parse(*this, ArgName, Arg, Val))
       return true; // Parse error!
     this->setValue(Val);
     this->setPosition(pos);
     Callback(Val);
     return false;
   }
 
   enum ValueExpected getValueExpectedFlagDefault() const override {
     return Parser.getValueExpectedFlagDefault();
   }
 
   void getExtraOptionNames(SmallVectorImpl<StringRef> &OptionNames) override {
     return Parser.getExtraOptionNames(OptionNames);
   }
 
   // Forward printing stuff to the parser...
   size_t getOptionWidth() const override {
     return Parser.getOptionWidth(*this);
   }
 
   void printOptionInfo(size_t GlobalWidth) const override {
     Parser.printOptionInfo(*this, GlobalWidth);
   }
 
   void printOptionValue(size_t GlobalWidth, bool Force) const override {
     if (Force || !this->getDefault().compare(this->getValue())) {
       cl::printOptionDiff<ParserClass>(*this, Parser, this->getValue(),
                                        this->getDefault(), GlobalWidth);
     }
   }
 
   template <class T, class = std::enable_if_t<std::is_assignable_v<T &, T>>>
   void setDefaultImpl() {
     const OptionValue<DataType> &V = this->getDefault();
     if (V.hasValue())
       this->setValue(V.getValue());
     else
       this->setValue(T());
   }
 
   template <class T, class = std::enable_if_t<!std::is_assignable_v<T &, T>>>
   void setDefaultImpl(...) {}
 
   void setDefault() override { setDefaultImpl<DataType>(); }
 
   void done() {
     addArgument();
     Parser.initialize();
   }
 
 public:
   // Command line options should not be copyable
   opt(const opt &) = delete;
   opt &operator=(const opt &) = delete;
 
   // setInitialValue - Used by the cl::init modifier...
   void setInitialValue(const DataType &V) { this->setValue(V, true); }
 
   ParserClass &getParser() { return Parser; }
 
   template <class T> DataType &operator=(const T &Val) {
     this->setValue(Val);
     Callback(Val);
     return this->getValue();
   }
 
   template <class... Mods>
   explicit opt(const Mods &... Ms)
       : Option(llvm::cl::Optional, NotHidden), Parser(*this) {
     apply(this, Ms...);
     done();
   }
 
   void setCallback(
       std::function<void(const typename ParserClass::parser_data_type &)> CB) {
     Callback = CB;
   }
 
   std::function<void(const typename ParserClass::parser_data_type &)> Callback =
       [](const typename ParserClass::parser_data_type &) {};
 };
 
 extern template class opt<unsigned>;
 extern template class opt<int>;
 extern template class opt<std::string>;
 extern template class opt<char>;
 extern template class opt<bool>;
 
 //===----------------------------------------------------------------------===//
 // Default storage class definition: external storage.  This implementation
 // assumes the user will specify a variable to store the data into with the
 // cl::location(x) modifier.
 //
 template <class DataType, class StorageClass> class list_storage {
   StorageClass *Location = nullptr; // Where to store the object...
   std::vector<OptionValue<DataType>> Default =
       std::vector<OptionValue<DataType>>();
   bool DefaultAssigned = false;
 
 public:
   list_storage() = default;
 
   void clear() {}
 
   bool setLocation(Option &O, StorageClass &L) {
     if (Location)
       return O.error("cl::location(x) specified more than once!");
     Location = &L;
     return false;
   }
 
   template <class T> void addValue(const T &V, bool initial = false) {
     assert(Location != nullptr &&
            "cl::location(...) not specified for a command "
            "line option with external storage!");
     Location->push_back(V);
     if (initial)
       Default.push_back(V);
   }
 
   const std::vector<OptionValue<DataType>> &getDefault() const {
     return Default;
   }
 
   void assignDefault() { DefaultAssigned = true; }
   void overwriteDefault() { DefaultAssigned = false; }
   bool isDefaultAssigned() { return DefaultAssigned; }
 };
 
 // Define how to hold a class type object, such as a string.
 // Originally this code inherited from std::vector. In transitioning to a new
 // API for command line options we should change this. The new implementation
 // of this list_storage specialization implements the minimum subset of the
 // std::vector API required for all the current clients.
 //
 // FIXME: Reduce this API to a more narrow subset of std::vector
 //
 template <class DataType> class list_storage<DataType, bool> {
   std::vector<DataType> Storage;
   std::vector<OptionValue<DataType>> Default;
   bool DefaultAssigned = false;
 
 public:
   using iterator = typename std::vector<DataType>::iterator;
 
   iterator begin() { return Storage.begin(); }
   iterator end() { return Storage.end(); }
 
   using const_iterator = typename std::vector<DataType>::const_iterator;
 
   const_iterator begin() const { return Storage.begin(); }
   const_iterator end() const { return Storage.end(); }
 
   using size_type = typename std::vector<DataType>::size_type;
 
   size_type size() const { return Storage.size(); }
 
   bool empty() const { return Storage.empty(); }
 
   void push_back(const DataType &value) { Storage.push_back(value); }
   void push_back(DataType &&value) { Storage.push_back(value); }
 
   using reference = typename std::vector<DataType>::reference;
   using const_reference = typename std::vector<DataType>::const_reference;
 
   reference operator[](size_type pos) { return Storage[pos]; }
   const_reference operator[](size_type pos) const { return Storage[pos]; }
 
   void clear() {
     Storage.clear();
   }
 
   iterator erase(const_iterator pos) { return Storage.erase(pos); }
   iterator erase(const_iterator first, const_iterator last) {
     return Storage.erase(first, last);
   }
 
   iterator erase(iterator pos) { return Storage.erase(pos); }
   iterator erase(iterator first, iterator last) {
     return Storage.erase(first, last);
   }
 
   iterator insert(const_iterator pos, const DataType &value) {
     return Storage.insert(pos, value);
   }
   iterator insert(const_iterator pos, DataType &&value) {
     return Storage.insert(pos, value);
   }
 
   iterator insert(iterator pos, const DataType &value) {
     return Storage.insert(pos, value);
   }
   iterator insert(iterator pos, DataType &&value) {
     return Storage.insert(pos, value);
   }
 
   reference front() { return Storage.front(); }
   const_reference front() const { return Storage.front(); }
 
   operator std::vector<DataType> &() { return Storage; }
   operator ArrayRef<DataType>() const { return Storage; }
   std::vector<DataType> *operator&() { return &Storage; }
   const std::vector<DataType> *operator&() const { return &Storage; }
 
   template <class T> void addValue(const T &V, bool initial = false) {
     Storage.push_back(V);
     if (initial)
       Default.push_back(OptionValue<DataType>(V));
   }
 
   const std::vector<OptionValue<DataType>> &getDefault() const {
     return Default;
   }
 
   void assignDefault() { DefaultAssigned = true; }
   void overwriteDefault() { DefaultAssigned = false; }
   bool isDefaultAssigned() { return DefaultAssigned; }
 };
 
 //===----------------------------------------------------------------------===//
 // A list of command line options.
 //
 template <class DataType, class StorageClass = bool,
           class ParserClass = parser<DataType>>
 class list : public Option, public list_storage<DataType, StorageClass> {
   std::vector<unsigned> Positions;
   ParserClass Parser;
 
   enum ValueExpected getValueExpectedFlagDefault() const override {
     return Parser.getValueExpectedFlagDefault();
   }
 
   void getExtraOptionNames(SmallVectorImpl<StringRef> &OptionNames) override {
     return Parser.getExtraOptionNames(OptionNames);
   }
 
   bool handleOccurrence(unsigned pos, StringRef ArgName,
                         StringRef Arg) override {
     typename ParserClass::parser_data_type Val =
         typename ParserClass::parser_data_type();
     if (list_storage<DataType, StorageClass>::isDefaultAssigned()) {
       clear();
       list_storage<DataType, StorageClass>::overwriteDefault();
     }
     if (Parser.parse(*this, ArgName, Arg, Val))
       return true; // Parse Error!
     list_storage<DataType, StorageClass>::addValue(Val);
     setPosition(pos);
     Positions.push_back(pos);
     Callback(Val);
     return false;
   }
 
   // Forward printing stuff to the parser...
   size_t getOptionWidth() const override {
     return Parser.getOptionWidth(*this);
   }
 
   void printOptionInfo(size_t GlobalWidth) const override {
     Parser.printOptionInfo(*this, GlobalWidth);
   }
 
   // Unimplemented: list options don't currently store their default value.
   void printOptionValue(size_t /*GlobalWidth*/, bool /*Force*/) const override {
   }
 
   void setDefault() override {
     Positions.clear();
     list_storage<DataType, StorageClass>::clear();
     for (auto &Val : list_storage<DataType, StorageClass>::getDefault())
       list_storage<DataType, StorageClass>::addValue(Val.getValue());
   }
 
   void done() {
     addArgument();
     Parser.initialize();
   }
 
 public:
   // Command line options should not be copyable
   list(const list &) = delete;
   list &operator=(const list &) = delete;
 
   ParserClass &getParser() { return Parser; }
 
   unsigned getPosition(unsigned optnum) const {
     assert(optnum < this->size() && "Invalid option index");
     return Positions[optnum];
   }
 
   void clear() {
     Positions.clear();
     list_storage<DataType, StorageClass>::clear();
   }
 
   // setInitialValues - Used by the cl::list_init modifier...
   void setInitialValues(ArrayRef<DataType> Vs) {
     assert(!(list_storage<DataType, StorageClass>::isDefaultAssigned()) &&
            "Cannot have two default values");
     list_storage<DataType, StorageClass>::assignDefault();
     for (auto &Val : Vs)
       list_storage<DataType, StorageClass>::addValue(Val, true);
   }
 
   void setNumAdditionalVals(unsigned n) { Option::setNumAdditionalVals(n); }
 
   template <class... Mods>
   explicit list(const Mods &... Ms)
       : Option(ZeroOrMore, NotHidden), Parser(*this) {
     apply(this, Ms...);
     done();
   }
 
   void setCallback(
       std::function<void(const typename ParserClass::parser_data_type &)> CB) {
     Callback = CB;
   }
 
   std::function<void(const typename ParserClass::parser_data_type &)> Callback =
       [](const typename ParserClass::parser_data_type &) {};
 };
 
 // Modifier to set the number of additional values.
 struct multi_val {
   unsigned AdditionalVals;
   explicit multi_val(unsigned N) : AdditionalVals(N) {}
 
   template <typename D, typename S, typename P>
   void apply(list<D, S, P> &L) const {
     L.setNumAdditionalVals(AdditionalVals);
   }
 };
 
 //===----------------------------------------------------------------------===//
 // Default storage class definition: external storage.  This implementation
 // assumes the user will specify a variable to store the data into with the
 // cl::location(x) modifier.
 //
 template <class DataType, class StorageClass> class bits_storage {
   unsigned *Location = nullptr; // Where to store the bits...
 
   template <class T> static unsigned Bit(const T &V) {
     unsigned BitPos = static_cast<unsigned>(V);
     assert(BitPos < sizeof(unsigned) * CHAR_BIT &&
            "enum exceeds width of bit vector!");
     return 1 << BitPos;
   }
 
 public:
   bits_storage() = default;
 
   bool setLocation(Option &O, unsigned &L) {
     if (Location)
       return O.error("cl::location(x) specified more than once!");
     Location = &L;
     return false;
   }
 
   template <class T> void addValue(const T &V) {
     assert(Location != nullptr &&
            "cl::location(...) not specified for a command "
            "line option with external storage!");
     *Location |= Bit(V);
   }
 
   unsigned getBits() { return *Location; }
 
   void clear() {
     if (Location)
       *Location = 0;
   }
 
   template <class T> bool isSet(const T &V) {
     return (*Location & Bit(V)) != 0;
   }
 };
 
 // Define how to hold bits.  Since we can inherit from a class, we do so.
 // This makes us exactly compatible with the bits in all cases that it is used.
 //
 template <class DataType> class bits_storage<DataType, bool> {
   unsigned Bits{0}; // Where to store the bits...
 
   template <class T> static unsigned Bit(const T &V) {
     unsigned BitPos = static_cast<unsigned>(V);
     assert(BitPos < sizeof(unsigned) * CHAR_BIT &&
            "enum exceeds width of bit vector!");
     return 1 << BitPos;
   }
 
 public:
   template <class T> void addValue(const T &V) { Bits |= Bit(V); }
 
   unsigned getBits() { return Bits; }
 
   void clear() { Bits = 0; }
 
   template <class T> bool isSet(const T &V) { return (Bits & Bit(V)) != 0; }
 };
 
 //===----------------------------------------------------------------------===//
 // A bit vector of command options.
 //
 template <class DataType, class Storage = bool,
           class ParserClass = parser<DataType>>
 class bits : public Option, public bits_storage<DataType, Storage> {
   std::vector<unsigned> Positions;
   ParserClass Parser;
 
   enum ValueExpected getValueExpectedFlagDefault() const override {
     return Parser.getValueExpectedFlagDefault();
   }
 
   void getExtraOptionNames(SmallVectorImpl<StringRef> &OptionNames) override {
     return Parser.getExtraOptionNames(OptionNames);
   }
 
   bool handleOccurrence(unsigned pos, StringRef ArgName,
                         StringRef Arg) override {
     typename ParserClass::parser_data_type Val =
         typename ParserClass::parser_data_type();
     if (Parser.parse(*this, ArgName, Arg, Val))
       return true; // Parse Error!
     this->addValue(Val);
     setPosition(pos);
     Positions.push_back(pos);
     Callback(Val);
     return false;
   }
 
   // Forward printing stuff to the parser...
   size_t getOptionWidth() const override {
     return Parser.getOptionWidth(*this);
   }
 
   void printOptionInfo(size_t GlobalWidth) const override {
     Parser.printOptionInfo(*this, GlobalWidth);
   }
 
   // Unimplemented: bits options don't currently store their default values.
   void printOptionValue(size_t /*GlobalWidth*/, bool /*Force*/) const override {
   }
 
   void setDefault() override { bits_storage<DataType, Storage>::clear(); }
 
   void done() {
     addArgument();
     Parser.initialize();
   }
 
 public:
   // Command line options should not be copyable
   bits(const bits &) = delete;
   bits &operator=(const bits &) = delete;
 
   ParserClass &getParser() { return Parser; }
 
   unsigned getPosition(unsigned optnum) const {
     assert(optnum < this->size() && "Invalid option index");
     return Positions[optnum];
   }
 
   template <class... Mods>
   explicit bits(const Mods &... Ms)
       : Option(ZeroOrMore, NotHidden), Parser(*this) {
     apply(this, Ms...);
     done();
   }
 
   void setCallback(
       std::function<void(const typename ParserClass::parser_data_type &)> CB) {
     Callback = CB;
   }
 
   std::function<void(const typename ParserClass::parser_data_type &)> Callback =
       [](const typename ParserClass::parser_data_type &) {};
 };
 
 //===----------------------------------------------------------------------===//
 // Aliased command line option (alias this name to a preexisting name)
 //
 
 class alias : public Option {
   Option *AliasFor;
 
   bool handleOccurrence(unsigned pos, StringRef /*ArgName*/,
                         StringRef Arg) override {
     return AliasFor->handleOccurrence(pos, AliasFor->ArgStr, Arg);
   }
 
   bool addOccurrence(unsigned pos, StringRef /*ArgName*/, StringRef Value,
                      bool MultiArg = false) override {
     return AliasFor->addOccurrence(pos, AliasFor->ArgStr, Value, MultiArg);
   }
 
   // Handle printing stuff...
   size_t getOptionWidth() const override;
   void printOptionInfo(size_t GlobalWidth) const override;
 
   // Aliases do not need to print their values.
   void printOptionValue(size_t /*GlobalWidth*/, bool /*Force*/) const override {
   }
 
   void setDefault() override { AliasFor->setDefault(); }
 
   ValueExpected getValueExpectedFlagDefault() const override {
     return AliasFor->getValueExpectedFlag();
   }
 
   void done() {
     if (!hasArgStr())
       error("cl::alias must have argument name specified!");
     if (!AliasFor)
       error("cl::alias must have an cl::aliasopt(option) specified!");
     if (!Subs.empty())
       error("cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!");
     Subs = AliasFor->Subs;
     Categories = AliasFor->Categories;
     addArgument();
   }
 
 public:
   // Command line options should not be copyable
   alias(const alias &) = delete;
   alias &operator=(const alias &) = delete;
 
   void setAliasFor(Option &O) {
     if (AliasFor)
       error("cl::alias must only have one cl::aliasopt(...) specified!");
     AliasFor = &O;
   }
 
   template <class... Mods>
   explicit alias(const Mods &... Ms)
       : Option(Optional, Hidden), AliasFor(nullptr) {
     apply(this, Ms...);
     done();
   }
 };
 
 // Modifier to set the option an alias aliases.
 struct aliasopt {
   Option &Opt;
 
   explicit aliasopt(Option &O) : Opt(O) {}
 
   void apply(alias &A) const { A.setAliasFor(Opt); }
 };
 
 // Provide additional help at the end of the normal help output. All occurrences
 // of cl::extrahelp will be accumulated and printed to stderr at the end of the
 // regular help, just before exit is called.
 struct extrahelp {
   StringRef morehelp;
 
   explicit extrahelp(StringRef help);
 };
 
 void PrintVersionMessage();
 
 /// This function just prints the help message, exactly the same way as if the
 /// -help or -help-hidden option had been given on the command line.
 ///
 /// \param Hidden if true will print hidden options
 /// \param Categorized if true print options in categories
 void PrintHelpMessage(bool Hidden = false, bool Categorized = false);
 
 /// An array of optional enabled settings in the LLVM build configuration,
 /// which may be of interest to compiler developers. For example, includes
 /// "+assertions" if assertions are enabled. Used by printBuildConfig.
 ArrayRef<StringRef> getCompilerBuildConfig();
 
 /// Prints the compiler build configuration.
 /// Designed for compiler developers, not compiler end-users.
 /// Intended to be used in --version output when enabled.
 void printBuildConfig(raw_ostream &OS);
 
 //===----------------------------------------------------------------------===//
 // Public interface for accessing registered options.
 //
 
 /// Use this to get a StringMap to all registered named options
 /// (e.g. -help).
 ///
 /// \return A reference to the StringMap used by the cl APIs to parse options.
 ///
 /// Access to unnamed arguments (i.e. positional) are not provided because
 /// it is expected that the client already has access to these.
 ///
 /// Typical usage:
 /// \code
 /// main(int argc,char* argv[]) {
 /// StringMap<llvm::cl::Option*> &opts = llvm::cl::getRegisteredOptions();
 /// assert(opts.count("help") == 1)
 /// opts["help"]->setDescription("Show alphabetical help information")
 /// // More code
 /// llvm::cl::ParseCommandLineOptions(argc,argv);
 /// //More code
 /// }
 /// \endcode
 ///
 /// This interface is useful for modifying options in libraries that are out of
 /// the control of the client. The options should be modified before calling
 /// llvm::cl::ParseCommandLineOptions().
 ///
 /// Hopefully this API can be deprecated soon. Any situation where options need
 /// to be modified by tools or libraries should be handled by sane APIs rather
 /// than just handing around a global list.
 StringMap<Option *> &
 getRegisteredOptions(SubCommand &Sub = SubCommand::getTopLevel());
 
 /// Use this to get all registered SubCommands from the provided parser.
 ///
 /// \return A range of all SubCommand pointers registered with the parser.
 ///
 /// Typical usage:
 /// \code
 /// main(int argc, char* argv[]) {
 ///   llvm::cl::ParseCommandLineOptions(argc, argv);
 ///   for (auto* S : llvm::cl::getRegisteredSubcommands()) {
 ///     if (*S) {
 ///       std::cout << "Executing subcommand: " << S->getName() << std::endl;
 ///       // Execute some function based on the name...
 ///     }
 ///   }
 /// }
 /// \endcode
 ///
 /// This interface is useful for defining subcommands in libraries and
 /// the dispatch from a single point (like in the main function).
 iterator_range<typename SmallPtrSet<SubCommand *, 4>::iterator>
 getRegisteredSubcommands();
 
 //===----------------------------------------------------------------------===//
 // Standalone command line processing utilities.
 //
 
 /// Tokenizes a command line that can contain escapes and quotes.
 //
 /// The quoting rules match those used by GCC and other tools that use
 /// libiberty's buildargv() or expandargv() utilities, and do not match bash.
 /// They differ from buildargv() on treatment of backslashes that do not escape
 /// a special character to make it possible to accept most Windows file paths.
 ///
 /// \param [in] Source The string to be split on whitespace with quotes.
 /// \param [in] Saver Delegates back to the caller for saving parsed strings.
 /// \param [in] MarkEOLs true if tokenizing a response file and you want end of
 /// lines and end of the response file to be marked with a nullptr string.
 /// \param [out] NewArgv All parsed strings are appended to NewArgv.
 void TokenizeGNUCommandLine(StringRef Source, StringSaver &Saver,
                             SmallVectorImpl<const char *> &NewArgv,
                             bool MarkEOLs = false);
 
 /// Tokenizes a string of Windows command line arguments, which may contain
 /// quotes and escaped quotes.
 ///
 /// See MSDN docs for CommandLineToArgvW for information on the quoting rules.
 /// http://msdn.microsoft.com/en-us/library/windows/desktop/17w5ykft(v=vs.85).aspx
 ///
 /// For handling a full Windows command line including the executable name at
 /// the start, see TokenizeWindowsCommandLineFull below.
 ///
 /// \param [in] Source The string to be split on whitespace with quotes.
 /// \param [in] Saver Delegates back to the caller for saving parsed strings.
 /// \param [in] MarkEOLs true if tokenizing a response file and you want end of
 /// lines and end of the response file to be marked with a nullptr string.
 /// \param [out] NewArgv All parsed strings are appended to NewArgv.
 void TokenizeWindowsCommandLine(StringRef Source, StringSaver &Saver,
                                 SmallVectorImpl<const char *> &NewArgv,
                                 bool MarkEOLs = false);
 
 /// Tokenizes a Windows command line while attempting to avoid copies. If no
 /// quoting or escaping was used, this produces substrings of the original
 /// string. If a token requires unquoting, it will be allocated with the
 /// StringSaver.
 void TokenizeWindowsCommandLineNoCopy(StringRef Source, StringSaver &Saver,
                                       SmallVectorImpl<StringRef> &NewArgv);
 
 /// Tokenizes a Windows full command line, including command name at the start.
 ///
 /// This uses the same syntax rules as TokenizeWindowsCommandLine for all but
 /// the first token. But the first token is expected to be parsed as the
 /// executable file name in the way CreateProcess would do it, rather than the
 /// way the C library startup code would do it: CreateProcess does not consider
 /// that \ is ever an escape character (because " is not a valid filename char,
 /// hence there's never a need to escape it to be used literally).
 ///
 /// Parameters are the same as for TokenizeWindowsCommandLine. In particular,
 /// if you set MarkEOLs = true, then the first word of every line will be
 /// parsed using the special rules for command names, making this function
 /// suitable for parsing a file full of commands to execute.
 void TokenizeWindowsCommandLineFull(StringRef Source, StringSaver &Saver,
                                     SmallVectorImpl<const char *> &NewArgv,
                                     bool MarkEOLs = false);
 
 /// String tokenization function type.  Should be compatible with either
 /// Windows or Unix command line tokenizers.
 using TokenizerCallback = void (*)(StringRef Source, StringSaver &Saver,
                                    SmallVectorImpl<const char *> &NewArgv,
                                    bool MarkEOLs);
 
 /// Tokenizes content of configuration file.
 ///
 /// \param [in] Source The string representing content of config file.
 /// \param [in] Saver Delegates back to the caller for saving parsed strings.
 /// \param [out] NewArgv All parsed strings are appended to NewArgv.
 /// \param [in] MarkEOLs Added for compatibility with TokenizerCallback.
 ///
 /// It works like TokenizeGNUCommandLine with ability to skip comment lines.
 ///
 void tokenizeConfigFile(StringRef Source, StringSaver &Saver,
                         SmallVectorImpl<const char *> &NewArgv,
                         bool MarkEOLs = false);
 
 /// Contains options that control response file expansion.
 class ExpansionContext {
   /// Provides persistent storage for parsed strings.
   StringSaver Saver;
 
   /// Tokenization strategy. Typically Unix or Windows.
   TokenizerCallback Tokenizer;
 
   /// File system used for all file access when running the expansion.
   vfs::FileSystem *FS;
 
   /// Path used to resolve relative rsp files. If empty, the file system
   /// current directory is used instead.
   StringRef CurrentDir;
 
   /// Directories used for search of config files.
   ArrayRef<StringRef> SearchDirs;
 
   /// True if names of nested response files must be resolved relative to
   /// including file.
   bool RelativeNames = false;
 
   /// If true, mark end of lines and the end of the response file with nullptrs
   /// in the Argv vector.
   bool MarkEOLs = false;
 
   /// If true, body of config file is expanded.
   bool InConfigFile = false;
 
   llvm::Error expandResponseFile(StringRef FName,
                                  SmallVectorImpl<const char *> &NewArgv);
 
 public:
   ExpansionContext(BumpPtrAllocator &A, TokenizerCallback T);
 
   ExpansionContext &setMarkEOLs(bool X) {
     MarkEOLs = X;
     return *this;
   }
 
   ExpansionContext &setRelativeNames(bool X) {
     RelativeNames = X;
     return *this;
   }
 
   ExpansionContext &setCurrentDir(StringRef X) {
     CurrentDir = X;
     return *this;
   }
 
   ExpansionContext &setSearchDirs(ArrayRef<StringRef> X) {
     SearchDirs = X;
     return *this;
   }
 
   ExpansionContext &setVFS(vfs::FileSystem *X) {
     FS = X;
     return *this;
   }
 
   /// Looks for the specified configuration file.
   ///
   /// \param[in]  FileName Name of the file to search for.
   /// \param[out] FilePath File absolute path, if it was found.
   /// \return True if file was found.
   ///
   /// If the specified file name contains a directory separator, it is searched
   /// for by its absolute path. Otherwise looks for file sequentially in
   /// directories specified by SearchDirs field.
   bool findConfigFile(StringRef FileName, SmallVectorImpl<char> &FilePath);
 
   /// Reads command line options from the given configuration file.
   ///
   /// \param [in] CfgFile Path to configuration file.
   /// \param [out] Argv Array to which the read options are added.
   /// \return true if the file was successfully read.
   ///
   /// It reads content of the specified file, tokenizes it and expands "@file"
   /// commands resolving file names in them relative to the directory where
   /// CfgFilename resides. It also expands "<CFGDIR>" to the base path of the
   /// current config file.
   Error readConfigFile(StringRef CfgFile, SmallVectorImpl<const char *> &Argv);
 
   /// Expands constructs "@file" in the provided array of arguments recursively.
   Error expandResponseFiles(SmallVectorImpl<const char *> &Argv);
 };
 
 /// A convenience helper which concatenates the options specified by the
 /// environment variable EnvVar and command line options, then expands
 /// response files recursively.
 /// \return true if all @files were expanded successfully or there were none.
 bool expandResponseFiles(int Argc, const char *const *Argv, const char *EnvVar,
                          SmallVectorImpl<const char *> &NewArgv);
 
 /// A convenience helper which supports the typical use case of expansion
 /// function call.
 bool ExpandResponseFiles(StringSaver &Saver, TokenizerCallback Tokenizer,
                          SmallVectorImpl<const char *> &Argv);
 
 /// A convenience helper which concatenates the options specified by the
 /// environment variable EnvVar and command line options, then expands response
 /// files recursively. The tokenizer is a predefined GNU or Windows one.
 /// \return true if all @files were expanded successfully or there were none.
 bool expandResponseFiles(int Argc, const char *const *Argv, const char *EnvVar,
                          StringSaver &Saver,
                          SmallVectorImpl<const char *> &NewArgv);
 
 /// Mark all options not part of this category as cl::ReallyHidden.
 ///
 /// \param Category the category of options to keep displaying
 ///
 /// Some tools (like clang-format) like to be able to hide all options that are
 /// not specific to the tool. This function allows a tool to specify a single
 /// option category to display in the -help output.
 void HideUnrelatedOptions(cl::OptionCategory &Category,
                           SubCommand &Sub = SubCommand::getTopLevel());
 
 /// Mark all options not part of the categories as cl::ReallyHidden.
 ///
 /// \param Categories the categories of options to keep displaying.
 ///
 /// Some tools (like clang-format) like to be able to hide all options that are
 /// not specific to the tool. This function allows a tool to specify a single
 /// option category to display in the -help output.
 void HideUnrelatedOptions(ArrayRef<const cl::OptionCategory *> Categories,
                           SubCommand &Sub = SubCommand::getTopLevel());
 
 /// Reset all command line options to a state that looks as if they have
 /// never appeared on the command line.  This is useful for being able to parse
 /// a command line multiple times (especially useful for writing tests).
 void ResetAllOptionOccurrences();
 
 /// Reset the command line parser back to its initial state.  This
 /// removes
 /// all options, categories, and subcommands and returns the parser to a state
 /// where no options are supported.
 void ResetCommandLineParser();
 
 /// Parses `Arg` into the option handler `Handler`.
 bool ProvidePositionalOption(Option *Handler, StringRef Arg, int i);
 
 } // end namespace cl
 
 } // end namespace llvm
 
 #endif // LLVM_SUPPORT_COMMANDLINE_H

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