Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 1963 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Support/CommandLine.h b/clang-r353983/include/llvm/Support/CommandLine.h
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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/ManagedStatic.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 {
+
+class StringSaver;
+class raw_ostream;
+
+/// cl Namespace - This namespace contains all of the command line option
+/// processing machinery.  It is intentionally a short name to make qualified
+/// usage concise.
+namespace cl {
+
+//===----------------------------------------------------------------------===//
+// ParseCommandLineOptions - 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);
+
+//===----------------------------------------------------------------------===//
+// ParseEnvironmentOptions - Environment variable option processing alternate
+//                           entry point.
+//
+void ParseEnvironmentOptions(const char *progName, const char *envvar,
+                             const char *Overview = "");
+
+// Function pointer type for printing version information.
+using VersionPrinterTy = std::function<void(raw_ostream &)>;
+
+///===---------------------------------------------------------------------===//
+/// SetVersionPrinter - 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);
+
+///===---------------------------------------------------------------------===//
+/// AddExtraVersionPrinter - 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);
+
+// PrintOptionValues - 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
+
+  // ConsumeAfter - 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
+};
+
+// Formatting flags - 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.
+//
+// Grouping - With this option 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
+//
+
+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?
+  Grouping = 0x04          // Can this option group with other options?
+};
+
+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?
+};
+
+//===----------------------------------------------------------------------===//
+// Option Category class
+//
+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).
+extern OptionCategory GeneralCategory;
+
+//===----------------------------------------------------------------------===//
+// SubCommand class
+//
+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;
+
+  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.
+};
+
+// A special subcommand representing no subcommand
+extern ManagedStatic<SubCommand> TopLevelSubCommand;
+
+// A special subcommand that can be used to put an option into all subcommands.
+extern ManagedStatic<SubCommand> AllSubCommands;
+
+//===----------------------------------------------------------------------===//
+// Option Base class
+//
+class Option {
+  friend class alias;
+
+  // handleOccurrences - 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();
+
+  int NumOccurrences = 0; // The number of times specified
+  // Occurrences, HiddenFlag, and Formatting are all enum types but to avoid
+  // problems with signed enums in bitfields.
+  unsigned Occurrences : 3; // enum NumOccurrencesFlag
+  // not using the enum type for 'Value' because zero is an implementation
+  // detail representing the non-value
+  unsigned Value : 2;
+  unsigned HiddenFlag : 2; // enum OptionHidden
+  unsigned Formatting : 3; // enum FormattingFlags
+  unsigned Misc : 3;
+  unsigned Position = 0;       // Position of last occurrence of the option
+  unsigned AdditionalVals = 0; // 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
+  OptionCategory *Category; // The Category this option belongs to
+  SmallPtrSet<SubCommand *, 4> Subs; // The subcommands this option belongs to.
+  bool FullyInitialized = false; // Has addArgument been called?
+
+  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; }
+
+  // hasArgStr - 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 isConsumeAfter() const {
+    return getNumOccurrencesFlag() == cl::ConsumeAfter;
+  }
+
+  bool isInAllSubCommands() const {
+    return any_of(Subs, [](const SubCommand *SC) {
+      return SC == &*AllSubCommands;
+    });
+  }
+
+  //-------------------------------------------------------------------------===
+  // 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 setCategory(OptionCategory &C) { Category = &C; }
+  void addSubCommand(SubCommand &S) { Subs.insert(&S); }
+
+protected:
+  explicit Option(enum NumOccurrencesFlag OccurrencesFlag,
+                  enum OptionHidden Hidden)
+      : Occurrences(OccurrencesFlag), Value(0), HiddenFlag(Hidden),
+        Formatting(NormalFormatting), Misc(0), Category(&GeneralCategory) {}
+
+  inline void setNumAdditionalVals(unsigned n) { AdditionalVals = n; }
+
+public:
+  virtual ~Option() = default;
+
+  // addArgument - 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;
+
+  // printOptionInfo - 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;
+
+  static void printHelpStr(StringRef HelpStr, size_t Indent,
+                           size_t FirstLineIndentedBy);
+
+  virtual void getExtraOptionNames(SmallVectorImpl<StringRef> &) {}
+
+  // addOccurrence - 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; }
+  inline void reset() { NumOccurrences = 0; }
+};
+
+//===----------------------------------------------------------------------===//
+// Command line option modifiers that can be used to modify the behavior of
+// command line option parsers...
+//
+
+// desc - 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); }
+};
+
+// value_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); }
+};
+
+// init - 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> initializer<Ty> init(const Ty &Val) {
+  return initializer<Ty>(Val);
+}
+
+// location - 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);
+}
+
+// cat - Specifiy 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.setCategory(Category); }
+};
+
+// sub - Specify the subcommand that this option belongs to.
+struct sub {
+  SubCommand &Sub;
+
+  sub(SubCommand &S) : Sub(S) {}
+
+  template <class Opt> void apply(Opt &O) const { O.addSubCommand(Sub); }
+};
+
+//===----------------------------------------------------------------------===//
+// OptionValue class
+
+// 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*/) {}
+
+  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;
+  }
+
+  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<DataType>::value> {
+  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 }
+
+// values - 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 (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...});
+}
+
+//===----------------------------------------------------------------------===//
+// parser class - 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.
+
+//--------------------------------------------------
+// generic_parser_base - 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
+
+  // getNumOptions - Virtual function implemented by generic subclass to
+  // indicate how many entries are in Values.
+  //
+  virtual unsigned getNumOptions() const = 0;
+
+  // getOption - Return option name N.
+  virtual StringRef getOption(unsigned N) const = 0;
+
+  // getDescription - 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;
+
+  // printOptionInfo - 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;
+
+  // printOptionDiff - 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;
+  }
+
+  // findOption - 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;
+  }
+
+  // getOptionValue - Return the value of option name N.
+  const GenericOptionValue &getOptionValue(unsigned N) const override {
+    return Values[N].V;
+  }
+
+  // parse - 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 + "'!");
+  }
+
+  /// addLiteralOption - Add an entry to the mapping table.
+  ///
+  template <class DT>
+  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);
+    AddLiteralOption(Owner, Name);
+  }
+
+  /// removeLiteralOption - Remove the specified option.
+  ///
+  void removeLiteralOption(StringRef Name) {
+    unsigned N = findOption(Name);
+    assert(N != Values.size() && "Option not found!");
+    Values.erase(Values.begin() + N);
+  }
+};
+
+//--------------------------------------------------
+// basic_parser - Super class of parsers to provide boilerplate code
+//
+class basic_parser_impl { // non-template implementation of basic_parser<t>
+public:
+  basic_parser_impl(Option &) {}
+
+  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;
+
+  // printOptionInfo - Print out information about this option.  The
+  // to-be-maintained width is specified.
+  //
+  void printOptionInfo(const Option &O, size_t GlobalWidth) const;
+
+  // printOptionNoValue - Print a placeholder for options that don't yet support
+  // printOptionDiff().
+  void printOptionNoValue(const Option &O, size_t GlobalWidth) const;
+
+  // getValueName - 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:
+  ~basic_parser_impl() = default;
+
+  // A helper for basic_parser::printOptionDiff.
+  void printOptionName(const Option &O, size_t GlobalWidth) const;
+};
+
+// basic_parser - 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) {}
+
+protected:
+  ~basic_parser() = default;
+};
+
+//--------------------------------------------------
+// parser<bool>
+//
+template <> class parser<bool> final : public basic_parser<bool> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &O, StringRef ArgName, StringRef Arg, bool &Val);
+
+  void initialize() {}
+
+  enum ValueExpected getValueExpectedFlagDefault() const {
+    return ValueOptional;
+  }
+
+  // getValueName - 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<bool>;
+
+//--------------------------------------------------
+// parser<boolOrDefault>
+template <>
+class parser<boolOrDefault> final : public basic_parser<boolOrDefault> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &O, StringRef ArgName, StringRef Arg, boolOrDefault &Val);
+
+  enum ValueExpected getValueExpectedFlagDefault() const {
+    return ValueOptional;
+  }
+
+  // getValueName - 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<boolOrDefault>;
+
+//--------------------------------------------------
+// parser<int>
+//
+template <> class parser<int> final : public basic_parser<int> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &O, StringRef ArgName, StringRef Arg, int &Val);
+
+  // getValueName - 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<int>;
+
+//--------------------------------------------------
+// parser<unsigned>
+//
+template <> class parser<unsigned> final : public basic_parser<unsigned> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &O, StringRef ArgName, StringRef Arg, unsigned &Val);
+
+  // getValueName - 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>;
+
+//--------------------------------------------------
+// parser<unsigned long long>
+//
+template <>
+class parser<unsigned long long> final
+    : public basic_parser<unsigned long long> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &O, StringRef ArgName, StringRef Arg,
+             unsigned long long &Val);
+
+  // getValueName - Overload in subclass to provide a better default value.
+  StringRef getValueName() const override { return "uint"; }
+
+  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<unsigned long long>;
+
+//--------------------------------------------------
+// parser<double>
+//
+template <> class parser<double> final : public basic_parser<double> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &O, StringRef ArgName, StringRef Arg, double &Val);
+
+  // getValueName - 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<double>;
+
+//--------------------------------------------------
+// parser<float>
+//
+template <> class parser<float> final : public basic_parser<float> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &O, StringRef ArgName, StringRef Arg, float &Val);
+
+  // getValueName - 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<float>;
+
+//--------------------------------------------------
+// parser<std::string>
+//
+template <> class parser<std::string> final : public basic_parser<std::string> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &, StringRef, StringRef Arg, std::string &Value) {
+    Value = Arg.str();
+    return false;
+  }
+
+  // getValueName - 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<std::string>;
+
+//--------------------------------------------------
+// parser<char>
+//
+template <> class parser<char> final : public basic_parser<char> {
+public:
+  parser(Option &O) : basic_parser(O) {}
+
+  // parse - Return true on error.
+  bool parse(Option &, StringRef, StringRef Arg, char &Value) {
+    Value = Arg[0];
+    return false;
+  }
+
+  // getValueName - 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;
+};
+
+extern template class basic_parser<char>;
+
+//--------------------------------------------------
+// PrintOptionDiff
+//
+// 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);
+}
+
+//===----------------------------------------------------------------------===//
+// applicator class - 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) { O.setMiscFlag(MF); }
+};
+
+// apply method - 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);
+}
+
+//===----------------------------------------------------------------------===//
+// opt_storage class
+
+// 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(DataType()) {}
+
+  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; }
+};
+
+//===----------------------------------------------------------------------===//
+// opt - 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<DataType>::value> {
+  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);
+    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 = typename std::enable_if<
+            std::is_assignable<T&, T>::value>::type>
+  void setDefaultImpl() {
+    const OptionValue<DataType> &V = this->getDefault();
+    if (V.hasValue())
+      this->setValue(V.getValue());
+  }
+
+  template <class T, class = typename std::enable_if<
+            !std::is_assignable<T&, T>::value>::type>
+  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);
+    return this->getValue();
+  }
+
+  template <class... Mods>
+  explicit opt(const Mods &... Ms)
+      : Option(Optional, NotHidden), Parser(*this) {
+    apply(this, Ms...);
+    done();
+  }
+};
+
+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>;
+
+//===----------------------------------------------------------------------===//
+// list_storage class
+
+// 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...
+
+public:
+  list_storage() = default;
+
+  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) {
+    assert(Location != 0 && "cl::location(...) not specified for a command "
+                            "line option with external storage!");
+    Location->push_back(V);
+  }
+};
+
+// 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;
+
+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]; }
+
+  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>() { return Storage; }
+  std::vector<DataType> *operator&() { return &Storage; }
+  const std::vector<DataType> *operator&() const { return &Storage; }
+
+  template <class T> void addValue(const T &V) { Storage.push_back(V); }
+};
+
+//===----------------------------------------------------------------------===//
+// list - 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 (Parser.parse(*this, ArgName, Arg, Val))
+      return true; // Parse Error!
+    list_storage<DataType, StorageClass>::addValue(Val);
+    setPosition(pos);
+    Positions.push_back(pos);
+    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 {}
+
+  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 setNumAdditionalVals(unsigned n) { Option::setNumAdditionalVals(n); }
+
+  template <class... Mods>
+  explicit list(const Mods &... Ms)
+      : Option(ZeroOrMore, NotHidden), Parser(*this) {
+    apply(this, Ms...);
+    done();
+  }
+};
+
+// multi_val - 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);
+  }
+};
+
+//===----------------------------------------------------------------------===//
+// bits_storage class
+
+// 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 = reinterpret_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 != 0 && "cl::location(...) not specified for a command "
+                            "line option with external storage!");
+    *Location |= Bit(V);
+  }
+
+  unsigned getBits() { return *Location; }
+
+  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; // Where to store the bits...
+
+  template <class T> static unsigned Bit(const T &V) {
+    unsigned BitPos = (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; }
+
+  template <class T> bool isSet(const T &V) { return (Bits & Bit(V)) != 0; }
+};
+
+//===----------------------------------------------------------------------===//
+// bits - 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);
+    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 {}
+
+  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();
+  }
+};
+
+//===----------------------------------------------------------------------===//
+// 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!");
+    Subs = AliasFor->Subs;
+    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();
+  }
+};
+
+// aliasfor - 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); }
+};
+
+// extrahelp - 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);
+
+//===----------------------------------------------------------------------===//
+// Public interface for accessing registered options.
+//
+
+/// Use this to get a StringMap to all registered named options
+/// (e.g. -help). Note \p Map Should be an empty StringMap.
+///
+/// \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 = *TopLevelSubCommand);
+
+/// 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 Windows command line 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
+///
+/// \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);
+
+/// 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);
+
+/// Reads command line options from the given configuration file.
+///
+/// \param [in] CfgFileName Path to configuration file.
+/// \param [in] Saver  Objects that saves allocated strings.
+/// \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.
+///
+bool readConfigFile(StringRef CfgFileName, StringSaver &Saver,
+                    SmallVectorImpl<const char *> &Argv);
+
+/// Expand response files on a command line recursively using the given
+/// StringSaver and tokenization strategy.  Argv should contain the command line
+/// before expansion and will be modified in place. If requested, Argv will
+/// also be populated with nullptrs indicating where each response file line
+/// ends, which is useful for the "/link" argument that needs to consume all
+/// remaining arguments only until the next end of line, when in a response
+/// file.
+///
+/// \param [in] Saver Delegates back to the caller for saving parsed strings.
+/// \param [in] Tokenizer Tokenization strategy. Typically Unix or Windows.
+/// \param [in,out] Argv Command line into which to expand response files.
+/// \param [in] MarkEOLs Mark end of lines and the end of the response file
+/// with nullptrs in the Argv vector.
+/// \param [in] RelativeNames true if names of nested response files must be
+/// resolved relative to including file.
+/// \return true if all @files were expanded successfully or there were none.
+bool ExpandResponseFiles(StringSaver &Saver, TokenizerCallback Tokenizer,
+                         SmallVectorImpl<const char *> &Argv,
+                         bool MarkEOLs = false, bool RelativeNames = false);
+
+/// 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 = *TopLevelSubCommand);
+
+/// 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 = *TopLevelSubCommand);
+
+/// 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();
+
+} // end namespace cl
+
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_COMMANDLINE_H