Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- IdentifierTable.h - Hash table for identifier lookup -----*- 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

//

//===----------------------------------------------------------------------===//

//

/// \file

/// Defines the clang::IdentifierInfo, clang::IdentifierTable, and

/// clang::Selector interfaces.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_BASIC_IDENTIFIERTABLE_H

#define LLVM_CLANG_BASIC_IDENTIFIERTABLE_H

#include "clang/Basic/DiagnosticIDs.h"

#include "clang/Basic/LLVM.h"

#include "clang/Basic/TokenKinds.h"

#include "llvm/ADT/DenseMapInfo.h"

#include "llvm/ADT/SmallString.h"

#include "llvm/ADT/StringMap.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/Support/Allocator.h"

#include "llvm/Support/PointerLikeTypeTraits.h"

#include "llvm/Support/type_traits.h"

#include <cassert>

#include <cstddef>

#include <cstdint>

#include <cstring>

#include <string>

#include <utility>

namespace clang {

class DeclarationName;

class DeclarationNameTable;

class IdentifierInfo;

class LangOptions;

class MultiKeywordSelector;

class SourceLocation;

enum class ReservedIdentifierStatus {

  NotReserved = 0,

  StartsWithUnderscoreAtGlobalScope,

  StartsWithUnderscoreAndIsExternC,

  StartsWithDoubleUnderscore,

  StartsWithUnderscoreFollowedByCapitalLetter,

  ContainsDoubleUnderscore,

};

/// Determine whether an identifier is reserved for use as a name at global

/// scope. Such identifiers might be implementation-specific global functions

/// or variables.

inline bool isReservedAtGlobalScope(ReservedIdentifierStatus Status) {

  return Status != ReservedIdentifierStatus::NotReserved;

}

/// Determine whether an identifier is reserved in all contexts. Such

/// identifiers might be implementation-specific keywords or macros, for

/// example.

inline bool isReservedInAllContexts(ReservedIdentifierStatus Status) {

  return Status != ReservedIdentifierStatus::NotReserved &&

         Status != ReservedIdentifierStatus::StartsWithUnderscoreAtGlobalScope &&

         Status != ReservedIdentifierStatus::StartsWithUnderscoreAndIsExternC;

}

/// A simple pair of identifier info and location.

using IdentifierLocPair = std::pair<IdentifierInfo *, SourceLocation>;

/// IdentifierInfo and other related classes are aligned to

/// 8 bytes so that DeclarationName can use the lower 3 bits

/// of a pointer to one of these classes.

enum { IdentifierInfoAlignment = 8 };

static constexpr int ObjCOrBuiltinIDBits = 16;

/// One of these records is kept for each identifier that

/// is lexed.  This contains information about whether the token was \#define'd,

/// is a language keyword, or if it is a front-end token of some sort (e.g. a

/// variable or function name).  The preprocessor keeps this information in a

/// set, and all tok::identifier tokens have a pointer to one of these.

/// It is aligned to 8 bytes because DeclarationName needs the lower 3 bits.

class alignas(IdentifierInfoAlignment) IdentifierInfo {

  friend class IdentifierTable;

  // Front-end token ID or tok::identifier.

  unsigned TokenID : 9;

  // ObjC keyword ('protocol' in '@protocol') or builtin (__builtin_inf).

  // First NUM_OBJC_KEYWORDS values are for Objective-C,

  // the remaining values are for builtins.

  unsigned ObjCOrBuiltinID : ObjCOrBuiltinIDBits;

  // True if there is a #define for this.

  unsigned HasMacro : 1;

  // True if there was a #define for this.

  unsigned HadMacro : 1;

  // True if the identifier is a language extension.

  unsigned IsExtension : 1;

  // True if the identifier is a keyword in a newer or proposed Standard.

  unsigned IsFutureCompatKeyword : 1;

  // True if the identifier is poisoned.

  unsigned IsPoisoned : 1;

  // True if the identifier is a C++ operator keyword.

  unsigned IsCPPOperatorKeyword : 1;

  // Internal bit set by the member function RecomputeNeedsHandleIdentifier.

  // See comment about RecomputeNeedsHandleIdentifier for more info.

  unsigned NeedsHandleIdentifier : 1;

  // True if the identifier was loaded (at least partially) from an AST file.

  unsigned IsFromAST : 1;

  // True if the identifier has changed from the definition

  // loaded from an AST file.

  unsigned ChangedAfterLoad : 1;

  // True if the identifier's frontend information has changed from the

  // definition loaded from an AST file.

  unsigned FEChangedAfterLoad : 1;

  // True if revertTokenIDToIdentifier was called.

  unsigned RevertedTokenID : 1;

  // True if there may be additional information about

  // this identifier stored externally.

  unsigned OutOfDate : 1;

  // True if this is the 'import' contextual keyword.

  unsigned IsModulesImport : 1;

  // True if this is a mangled OpenMP variant name.

  unsigned IsMangledOpenMPVariantName : 1;

  // True if this is a deprecated macro.

  unsigned IsDeprecatedMacro : 1;

  // True if this macro is unsafe in headers.

  unsigned IsRestrictExpansion : 1;

  // True if this macro is final.

  unsigned IsFinal : 1;

  // 22 bits left in a 64-bit word.

  // Managed by the language front-end.

  void *FETokenInfo = nullptr;

  llvm::StringMapEntry<IdentifierInfo *> *Entry = nullptr;

  IdentifierInfo()

      : TokenID(tok::identifier), ObjCOrBuiltinID(0), HasMacro(false),

        HadMacro(false), IsExtension(false), IsFutureCompatKeyword(false),

        IsPoisoned(false), IsCPPOperatorKeyword(false),

        NeedsHandleIdentifier(false), IsFromAST(false), ChangedAfterLoad(false),

        FEChangedAfterLoad(false), RevertedTokenID(false), OutOfDate(false),

        IsModulesImport(false), IsMangledOpenMPVariantName(false),

        IsDeprecatedMacro(false), IsRestrictExpansion(false), IsFinal(false) {}

public:

  IdentifierInfo(const IdentifierInfo &) = delete;

  IdentifierInfo &operator=(const IdentifierInfo &) = delete;

  IdentifierInfo(IdentifierInfo &&) = delete;

  IdentifierInfo &operator=(IdentifierInfo &&) = delete;

  /// Return true if this is the identifier for the specified string.

  ///

  /// This is intended to be used for string literals only: II->isStr("foo").

  template <std::size_t StrLen>

  bool isStr(const char (&Str)[StrLen]) const {

    return getLength() == StrLen-1 &&

           memcmp(getNameStart(), Str, StrLen-1) == 0;

  }

  /// Return true if this is the identifier for the specified StringRef.

  bool isStr(llvm::StringRef Str) const {

    llvm::StringRef ThisStr(getNameStart(), getLength());

    return ThisStr == Str;

  }

  /// Return the beginning of the actual null-terminated string for this

  /// identifier.

  const char *getNameStart() const { return Entry->getKeyData(); }

  /// Efficiently return the length of this identifier info.

  unsigned getLength() const { return Entry->getKeyLength(); }

  /// Return the actual identifier string.

  StringRef getName() const {

    return StringRef(getNameStart(), getLength());

  }

  /// Return true if this identifier is \#defined to some other value.

  /// \note The current definition may be in a module and not currently visible.

  bool hasMacroDefinition() const {

    return HasMacro;

  }

  void setHasMacroDefinition(bool Val) {

    if (HasMacro == Val) return;

    HasMacro = Val;

    if (Val) {

      NeedsHandleIdentifier = true;

      HadMacro = true;

    } else {

      // If this is a final macro, make the deprecation and header unsafe bits

      // stick around after the undefinition so they apply to any redefinitions.

      if (!IsFinal) {

        // Because calling the setters of these calls recomputes, just set them

        // manually to avoid recomputing a bunch of times.

        IsDeprecatedMacro = false;

        IsRestrictExpansion = false;

      }

      RecomputeNeedsHandleIdentifier();

    }

  }

  /// Returns true if this identifier was \#defined to some value at any

  /// moment. In this case there should be an entry for the identifier in the

  /// macro history table in Preprocessor.

  bool hadMacroDefinition() const {

    return HadMacro;

  }

  bool isDeprecatedMacro() const { return IsDeprecatedMacro; }

  void setIsDeprecatedMacro(bool Val) {

    if (IsDeprecatedMacro == Val)

      return;

    IsDeprecatedMacro = Val;

    if (Val)

      NeedsHandleIdentifier = true;

    else

      RecomputeNeedsHandleIdentifier();

  }

  bool isRestrictExpansion() const { return IsRestrictExpansion; }

  void setIsRestrictExpansion(bool Val) {

    if (IsRestrictExpansion == Val)

      return;

    IsRestrictExpansion = Val;

    if (Val)

      NeedsHandleIdentifier = true;

    else

      RecomputeNeedsHandleIdentifier();

  }

  bool isFinal() const { return IsFinal; }

  void setIsFinal(bool Val) { IsFinal = Val; }

  /// If this is a source-language token (e.g. 'for'), this API

  /// can be used to cause the lexer to map identifiers to source-language

  /// tokens.

  tok::TokenKind getTokenID() const { return (tok::TokenKind)TokenID; }

  /// True if revertTokenIDToIdentifier() was called.

  bool hasRevertedTokenIDToIdentifier() const { return RevertedTokenID; }

  /// Revert TokenID to tok::identifier; used for GNU libstdc++ 4.2

  /// compatibility.

  ///

  /// TokenID is normally read-only but there are 2 instances where we revert it

  /// to tok::identifier for libstdc++ 4.2. Keep track of when this happens

  /// using this method so we can inform serialization about it.

  void revertTokenIDToIdentifier() {

    assert(TokenID != tok::identifier && "Already at tok::identifier");

    TokenID = tok::identifier;

    RevertedTokenID = true;

  }

  void revertIdentifierToTokenID(tok::TokenKind TK) {

    assert(TokenID == tok::identifier && "Should be at tok::identifier");

    TokenID = TK;

    RevertedTokenID = false;

  }

  /// Return the preprocessor keyword ID for this identifier.

  ///

  /// For example, "define" will return tok::pp_define.

  tok::PPKeywordKind getPPKeywordID() const;

  /// Return the Objective-C keyword ID for the this identifier.

  ///

  /// For example, 'class' will return tok::objc_class if ObjC is enabled.

  tok::ObjCKeywordKind getObjCKeywordID() const {

    if (ObjCOrBuiltinID < tok::NUM_OBJC_KEYWORDS)

      return tok::ObjCKeywordKind(ObjCOrBuiltinID);

    else

      return tok::objc_not_keyword;

  }

  void setObjCKeywordID(tok::ObjCKeywordKind ID) { ObjCOrBuiltinID = ID; }

  /// Return a value indicating whether this is a builtin function.

  ///

  /// 0 is not-built-in. 1+ are specific builtin functions.

  unsigned getBuiltinID() const {

    if (ObjCOrBuiltinID >= tok::NUM_OBJC_KEYWORDS)

      return ObjCOrBuiltinID - tok::NUM_OBJC_KEYWORDS;

    else

      return 0;

  }

  void setBuiltinID(unsigned ID) {

    ObjCOrBuiltinID = ID + tok::NUM_OBJC_KEYWORDS;

    assert(ObjCOrBuiltinID - unsigned(tok::NUM_OBJC_KEYWORDS) == ID

           && "ID too large for field!");

  }

  unsigned getObjCOrBuiltinID() const { return ObjCOrBuiltinID; }

  void setObjCOrBuiltinID(unsigned ID) { ObjCOrBuiltinID = ID; }

  /// get/setExtension - Initialize information about whether or not this

  /// language token is an extension.  This controls extension warnings, and is

  /// only valid if a custom token ID is set.

  bool isExtensionToken() const { return IsExtension; }

  void setIsExtensionToken(bool Val) {

    IsExtension = Val;

    if (Val)

      NeedsHandleIdentifier = true;

    else

      RecomputeNeedsHandleIdentifier();

  }

  /// is/setIsFutureCompatKeyword - Initialize information about whether or not

  /// this language token is a keyword in a newer or proposed Standard. This

  /// controls compatibility warnings, and is only true when not parsing the

  /// corresponding Standard. Once a compatibility problem has been diagnosed

  /// with this keyword, the flag will be cleared.

  bool isFutureCompatKeyword() const { return IsFutureCompatKeyword; }

  void setIsFutureCompatKeyword(bool Val) {

    IsFutureCompatKeyword = Val;

    if (Val)

      NeedsHandleIdentifier = true;

    else

      RecomputeNeedsHandleIdentifier();

  }

  /// setIsPoisoned - Mark this identifier as poisoned.  After poisoning, the

  /// Preprocessor will emit an error every time this token is used.

  void setIsPoisoned(bool Value = true) {

    IsPoisoned = Value;

    if (Value)

      NeedsHandleIdentifier = true;

    else

      RecomputeNeedsHandleIdentifier();

  }

  /// Return true if this token has been poisoned.

  bool isPoisoned() const { return IsPoisoned; }

  /// isCPlusPlusOperatorKeyword/setIsCPlusPlusOperatorKeyword controls whether

  /// this identifier is a C++ alternate representation of an operator.

  void setIsCPlusPlusOperatorKeyword(bool Val = true) {

    IsCPPOperatorKeyword = Val;

  }

  bool isCPlusPlusOperatorKeyword() const { return IsCPPOperatorKeyword; }

  /// Return true if this token is a keyword in the specified language.

  bool isKeyword(const LangOptions &LangOpts) const;

  /// Return true if this token is a C++ keyword in the specified

  /// language.

  bool isCPlusPlusKeyword(const LangOptions &LangOpts) const;

  /// Get and set FETokenInfo. The language front-end is allowed to associate

  /// arbitrary metadata with this token.

  void *getFETokenInfo() const { return FETokenInfo; }

  void setFETokenInfo(void *T) { FETokenInfo = T; }

  /// Return true if the Preprocessor::HandleIdentifier must be called

  /// on a token of this identifier.

  ///

  /// If this returns false, we know that HandleIdentifier will not affect

  /// the token.

  bool isHandleIdentifierCase() const { return NeedsHandleIdentifier; }

  /// Return true if the identifier in its current state was loaded

  /// from an AST file.

  bool isFromAST() const { return IsFromAST; }

  void setIsFromAST() { IsFromAST = true; }

  /// Determine whether this identifier has changed since it was loaded

  /// from an AST file.

  bool hasChangedSinceDeserialization() const {

    return ChangedAfterLoad;

  }

  /// Note that this identifier has changed since it was loaded from

  /// an AST file.

  void setChangedSinceDeserialization() {

    ChangedAfterLoad = true;

  }

  /// Determine whether the frontend token information for this

  /// identifier has changed since it was loaded from an AST file.

  bool hasFETokenInfoChangedSinceDeserialization() const {

    return FEChangedAfterLoad;

  }

  /// Note that the frontend token information for this identifier has

  /// changed since it was loaded from an AST file.

  void setFETokenInfoChangedSinceDeserialization() {

    FEChangedAfterLoad = true;

  }

  /// Determine whether the information for this identifier is out of

  /// date with respect to the external source.

  bool isOutOfDate() const { return OutOfDate; }

  /// Set whether the information for this identifier is out of

  /// date with respect to the external source.

  void setOutOfDate(bool OOD) {

    OutOfDate = OOD;

    if (OOD)

      NeedsHandleIdentifier = true;

    else

      RecomputeNeedsHandleIdentifier();

  }

  /// Determine whether this is the contextual keyword \c import.

  bool isModulesImport() const { return IsModulesImport; }

  /// Set whether this identifier is the contextual keyword \c import.

  void setModulesImport(bool I) {

    IsModulesImport = I;

    if (I)

      NeedsHandleIdentifier = true;

    else

      RecomputeNeedsHandleIdentifier();

  }

  /// Determine whether this is the mangled name of an OpenMP variant.

  bool isMangledOpenMPVariantName() const { return IsMangledOpenMPVariantName; }

  /// Set whether this is the mangled name of an OpenMP variant.

  void setMangledOpenMPVariantName(bool I) { IsMangledOpenMPVariantName = I; }

  /// Return true if this identifier is an editor placeholder.

  ///

  /// Editor placeholders are produced by the code-completion engine and are

  /// represented as characters between '<#' and '#>' in the source code. An

  /// example of auto-completed call with a placeholder parameter is shown

  /// below:

  /// \code

  ///   function(<#int x#>);

  /// \endcode

  bool isEditorPlaceholder() const {

    return getName().startswith("<#") && getName().endswith("#>");

  }

  /// Determine whether \p this is a name reserved for the implementation (C99

  /// 7.1.3, C++ [lib.global.names]).

  ReservedIdentifierStatus isReserved(const LangOptions &LangOpts) const;

  /// If the identifier is an "uglified" reserved name, return a cleaned form.

  /// e.g. _Foo => Foo. Otherwise, just returns the name.

  StringRef deuglifiedName() const;

  /// Provide less than operator for lexicographical sorting.

  bool operator<(const IdentifierInfo &RHS) const {

    return getName() < RHS.getName();

  }

private:

  /// The Preprocessor::HandleIdentifier does several special (but rare)

  /// things to identifiers of various sorts.  For example, it changes the

  /// \c for keyword token from tok::identifier to tok::for.

  ///

  /// This method is very tied to the definition of HandleIdentifier.  Any

  /// change to it should be reflected here.

  void RecomputeNeedsHandleIdentifier() {

    NeedsHandleIdentifier = isPoisoned() || hasMacroDefinition() ||

                            isExtensionToken() || isFutureCompatKeyword() ||

                            isOutOfDate() || isModulesImport();

  }

};

/// An RAII object for [un]poisoning an identifier within a scope.

///

/// \p II is allowed to be null, in which case objects of this type have

/// no effect.

class PoisonIdentifierRAIIObject {

  IdentifierInfo *const II;

  const bool OldValue;

public:

  PoisonIdentifierRAIIObject(IdentifierInfo *II, bool NewValue)

    : II(II), OldValue(II ? II->isPoisoned() : false) {

    if(II)

      II->setIsPoisoned(NewValue);

  }

  ~PoisonIdentifierRAIIObject() {

    if(II)

      II->setIsPoisoned(OldValue);

  }

};

/// An iterator that walks over all of the known identifiers

/// in the lookup table.

///

/// Since this iterator uses an abstract interface via virtual

/// functions, it uses an object-oriented interface rather than the

/// more standard C++ STL iterator interface. In this OO-style

/// iteration, the single function \c Next() provides dereference,

/// advance, and end-of-sequence checking in a single

/// operation. Subclasses of this iterator type will provide the

/// actual functionality.

class IdentifierIterator {

protected:

  IdentifierIterator() = default;

public:

  IdentifierIterator(const IdentifierIterator &) = delete;

  IdentifierIterator &operator=(const IdentifierIterator &) = delete;

  virtual ~IdentifierIterator();

  /// Retrieve the next string in the identifier table and

  /// advances the iterator for the following string.

  ///

  /// \returns The next string in the identifier table. If there is

  /// no such string, returns an empty \c StringRef.

  virtual StringRef Next() = 0;

};

/// Provides lookups to, and iteration over, IdentiferInfo objects.

class IdentifierInfoLookup {

public:

  virtual ~IdentifierInfoLookup();

  /// Return the IdentifierInfo for the specified named identifier.

  ///

  /// Unlike the version in IdentifierTable, this returns a pointer instead

  /// of a reference.  If the pointer is null then the IdentifierInfo cannot

  /// be found.

  virtual IdentifierInfo* get(StringRef Name) = 0;

  /// Retrieve an iterator into the set of all identifiers

  /// known to this identifier lookup source.

  ///

  /// This routine provides access to all of the identifiers known to

  /// the identifier lookup, allowing access to the contents of the

  /// identifiers without introducing the overhead of constructing

  /// IdentifierInfo objects for each.

  ///

  /// \returns A new iterator into the set of known identifiers. The

  /// caller is responsible for deleting this iterator.

  virtual IdentifierIterator *getIdentifiers();

};

/// Implements an efficient mapping from strings to IdentifierInfo nodes.

///

/// This has no other purpose, but this is an extremely performance-critical

/// piece of the code, as each occurrence of every identifier goes through

/// here when lexed.

class IdentifierTable {

  // Shark shows that using MallocAllocator is *much* slower than using this

  // BumpPtrAllocator!

  using HashTableTy = llvm::StringMap<IdentifierInfo *, llvm::BumpPtrAllocator>;

  HashTableTy HashTable;

  IdentifierInfoLookup* ExternalLookup;

public:

  /// Create the identifier table.

  explicit IdentifierTable(IdentifierInfoLookup *ExternalLookup = nullptr);

  /// Create the identifier table, populating it with info about the

  /// language keywords for the language specified by \p LangOpts.

  explicit IdentifierTable(const LangOptions &LangOpts,

                           IdentifierInfoLookup *ExternalLookup = nullptr);

  /// Set the external identifier lookup mechanism.

  void setExternalIdentifierLookup(IdentifierInfoLookup *IILookup) {

    ExternalLookup = IILookup;

  }

  /// Retrieve the external identifier lookup object, if any.

  IdentifierInfoLookup *getExternalIdentifierLookup() const {

    return ExternalLookup;

  }

  llvm::BumpPtrAllocator& getAllocator() {

    return HashTable.getAllocator();

  }

  /// Return the identifier token info for the specified named

  /// identifier.

  IdentifierInfo &get(StringRef Name) {

    auto &Entry = *HashTable.try_emplace(Name, nullptr).first;

    IdentifierInfo *&II = Entry.second;

    if (II) return *II;

    // No entry; if we have an external lookup, look there first.

    if (ExternalLookup) {

      II = ExternalLookup->get(Name);

      if (II)

        return *II;

    }

    // Lookups failed, make a new IdentifierInfo.

    void *Mem = getAllocator().Allocate<IdentifierInfo>();

    II = new (Mem) IdentifierInfo();

    // Make sure getName() knows how to find the IdentifierInfo

    // contents.

    II->Entry = &Entry;

    return *II;

  }

  IdentifierInfo &get(StringRef Name, tok::TokenKind TokenCode) {

    IdentifierInfo &II = get(Name);

    II.TokenID = TokenCode;

    assert(II.TokenID == (unsigned) TokenCode && "TokenCode too large");

    return II;

  }

  /// Gets an IdentifierInfo for the given name without consulting

  ///        external sources.

  ///

  /// This is a version of get() meant for external sources that want to

  /// introduce or modify an identifier. If they called get(), they would

  /// likely end up in a recursion.

  IdentifierInfo &getOwn(StringRef Name) {

    auto &Entry = *HashTable.insert(std::make_pair(Name, nullptr)).first;

    IdentifierInfo *&II = Entry.second;

    if (II)

      return *II;

    // Lookups failed, make a new IdentifierInfo.

    void *Mem = getAllocator().Allocate<IdentifierInfo>();

    II = new (Mem) IdentifierInfo();

    // Make sure getName() knows how to find the IdentifierInfo

    // contents.

    II->Entry = &Entry;

    // If this is the 'import' contextual keyword, mark it as such.

    if (Name.equals("import"))

      II->setModulesImport(true);

    return *II;

  }

  using iterator = HashTableTy::const_iterator;

  using const_iterator = HashTableTy::const_iterator;

  iterator begin() const { return HashTable.begin(); }

  iterator end() const   { return HashTable.end(); }

  unsigned size() const  { return HashTable.size(); }

  iterator find(StringRef Name) const { return HashTable.find(Name); }

  /// Print some statistics to stderr that indicate how well the

  /// hashing is doing.

  void PrintStats() const;

  /// Populate the identifier table with info about the language keywords

  /// for the language specified by \p LangOpts.

  void AddKeywords(const LangOptions &LangOpts);

  /// Returns the correct diagnostic to issue for a future-compat diagnostic

  /// warning. Note, this function assumes the identifier passed has already

  /// been determined to be a future compatible keyword.

  diag::kind getFutureCompatDiagKind(const IdentifierInfo &II,

                                     const LangOptions &LangOpts);

};

/// A family of Objective-C methods.

///

/// These families have no inherent meaning in the language, but are

/// nonetheless central enough in the existing implementations to

/// merit direct AST support.  While, in theory, arbitrary methods can

/// be considered to form families, we focus here on the methods

/// involving allocation and retain-count management, as these are the

/// most "core" and the most likely to be useful to diverse clients

/// without extra information.

///

/// Both selectors and actual method declarations may be classified

/// into families.  Method families may impose additional restrictions

/// beyond their selector name; for example, a method called '_init'

/// that returns void is not considered to be in the 'init' family

/// (but would be if it returned 'id').  It is also possible to

/// explicitly change or remove a method's family.  Therefore the

/// method's family should be considered the single source of truth.

enum ObjCMethodFamily {

  /// No particular method family.

  OMF_None,

  // Selectors in these families may have arbitrary arity, may be

  // written with arbitrary leading underscores, and may have

  // additional CamelCase "words" in their first selector chunk

  // following the family name.

  OMF_alloc,

  OMF_copy,

  OMF_init,

  OMF_mutableCopy,

  OMF_new,

  // These families are singletons consisting only of the nullary

  // selector with the given name.

  OMF_autorelease,

  OMF_dealloc,

  OMF_finalize,

  OMF_release,

  OMF_retain,

  OMF_retainCount,

  OMF_self,

  OMF_initialize,

  // performSelector families

  OMF_performSelector

};

/// Enough bits to store any enumerator in ObjCMethodFamily or

/// InvalidObjCMethodFamily.

enum { ObjCMethodFamilyBitWidth = 4 };

/// An invalid value of ObjCMethodFamily.

enum { InvalidObjCMethodFamily = (1 << ObjCMethodFamilyBitWidth) - 1 };

/// A family of Objective-C methods.

///

/// These are family of methods whose result type is initially 'id', but

/// but are candidate for the result type to be changed to 'instancetype'.

enum ObjCInstanceTypeFamily {

  OIT_None,

  OIT_Array,

  OIT_Dictionary,

  OIT_Singleton,

  OIT_Init,

  OIT_ReturnsSelf

};

enum ObjCStringFormatFamily {

  SFF_None,

  SFF_NSString,

  SFF_CFString

};

/// Smart pointer class that efficiently represents Objective-C method

/// names.

///

/// This class will either point to an IdentifierInfo or a

/// MultiKeywordSelector (which is private). This enables us to optimize

/// selectors that take no arguments and selectors that take 1 argument, which

/// accounts for 78% of all selectors in Cocoa.h.

class Selector {

  friend class Diagnostic;

  friend class SelectorTable; // only the SelectorTable can create these

  friend class DeclarationName; // and the AST's DeclarationName.

  enum IdentifierInfoFlag {

    // Empty selector = 0. Note that these enumeration values must

    // correspond to the enumeration values of DeclarationName::StoredNameKind

    ZeroArg  = 0x01,

    OneArg   = 0x02,

    MultiArg = 0x07,

    ArgFlags = 0x07

  };

  /// A pointer to the MultiKeywordSelector or IdentifierInfo. We use the low

  /// three bits of InfoPtr to store an IdentifierInfoFlag. Note that in any

  /// case IdentifierInfo and MultiKeywordSelector are already aligned to

  /// 8 bytes even on 32 bits archs because of DeclarationName.

  uintptr_t InfoPtr = 0;

  Selector(IdentifierInfo *II, unsigned nArgs) {

    InfoPtr = reinterpret_cast<uintptr_t>(II);

    assert((InfoPtr & ArgFlags) == 0 &&"Insufficiently aligned IdentifierInfo");

    assert(nArgs < 2 && "nArgs not equal to 0/1");

    InfoPtr |= nArgs+1;

  }

  Selector(MultiKeywordSelector *SI) {

    InfoPtr = reinterpret_cast<uintptr_t>(SI);

    assert((InfoPtr & ArgFlags) == 0 &&"Insufficiently aligned IdentifierInfo");

    InfoPtr |= MultiArg;

  }

  IdentifierInfo *getAsIdentifierInfo() const {

    if (getIdentifierInfoFlag() < MultiArg)

      return reinterpret_cast<IdentifierInfo *>(InfoPtr & ~ArgFlags);

    return nullptr;

  }

  MultiKeywordSelector *getMultiKeywordSelector() const {

    return reinterpret_cast<MultiKeywordSelector *>(InfoPtr & ~ArgFlags);

  }

  unsigned getIdentifierInfoFlag() const {

    return InfoPtr & ArgFlags;

  }

  static ObjCMethodFamily getMethodFamilyImpl(Selector sel);

  static ObjCStringFormatFamily getStringFormatFamilyImpl(Selector sel);

public:

  /// The default ctor should only be used when creating data structures that

  ///  will contain selectors.

  Selector() = default;

  explicit Selector(uintptr_t V) : InfoPtr(V) {}

  /// operator==/!= - Indicate whether the specified selectors are identical.

  bool operator==(Selector RHS) const {

    return InfoPtr == RHS.InfoPtr;

  }

  bool operator!=(Selector RHS) const {

    return InfoPtr != RHS.InfoPtr;

  }

  void *getAsOpaquePtr() const {

    return reinterpret_cast<void*>(InfoPtr);

  }

  /// Determine whether this is the empty selector.

  bool isNull() const { return InfoPtr == 0; }

  // Predicates to identify the selector type.

  bool isKeywordSelector() const {

    return getIdentifierInfoFlag() != ZeroArg;

  }

  bool isUnarySelector() const {

    return getIdentifierInfoFlag() == ZeroArg;

  }

  /// If this selector is the specific keyword selector described by Names.

  bool isKeywordSelector(ArrayRef<StringRef> Names) const;

  /// If this selector is the specific unary selector described by Name.

  bool isUnarySelector(StringRef Name) const;

  unsigned getNumArgs() const;

  /// Retrieve the identifier at a given position in the selector.