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      1 //===--- IdentifierTable.cpp - Hash table for identifier lookup -----------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file implements the IdentifierInfo, IdentifierVisitor, and
     11 // IdentifierTable interfaces.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "clang/Basic/CharInfo.h"
     16 #include "clang/Basic/IdentifierTable.h"
     17 #include "clang/Basic/LangOptions.h"
     18 #include "clang/Basic/OperatorKinds.h"
     19 #include "clang/Basic/Specifiers.h"
     20 #include "llvm/ADT/DenseMap.h"
     21 #include "llvm/ADT/FoldingSet.h"
     22 #include "llvm/ADT/SmallString.h"
     23 #include "llvm/Support/ErrorHandling.h"
     24 #include "llvm/Support/raw_ostream.h"
     25 #include <cstdio>
     26 
     27 using namespace clang;
     28 
     29 //===----------------------------------------------------------------------===//
     30 // IdentifierInfo Implementation
     31 //===----------------------------------------------------------------------===//
     32 
     33 IdentifierInfo::IdentifierInfo() {
     34   TokenID = tok::identifier;
     35   ObjCOrBuiltinID = 0;
     36   HasMacro = false;
     37   HadMacro = false;
     38   IsExtension = false;
     39   IsFutureCompatKeyword = false;
     40   IsPoisoned = false;
     41   IsCPPOperatorKeyword = false;
     42   NeedsHandleIdentifier = false;
     43   IsFromAST = false;
     44   ChangedAfterLoad = false;
     45   FEChangedAfterLoad = false;
     46   RevertedTokenID = false;
     47   OutOfDate = false;
     48   IsModulesImport = false;
     49   FETokenInfo = nullptr;
     50   Entry = nullptr;
     51 }
     52 
     53 //===----------------------------------------------------------------------===//
     54 // IdentifierTable Implementation
     55 //===----------------------------------------------------------------------===//
     56 
     57 IdentifierIterator::~IdentifierIterator() { }
     58 
     59 IdentifierInfoLookup::~IdentifierInfoLookup() {}
     60 
     61 namespace {
     62   /// \brief A simple identifier lookup iterator that represents an
     63   /// empty sequence of identifiers.
     64   class EmptyLookupIterator : public IdentifierIterator
     65   {
     66   public:
     67     StringRef Next() override { return StringRef(); }
     68   };
     69 }
     70 
     71 IdentifierIterator *IdentifierInfoLookup::getIdentifiers() {
     72   return new EmptyLookupIterator();
     73 }
     74 
     75 IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
     76                                  IdentifierInfoLookup* externalLookup)
     77   : HashTable(8192), // Start with space for 8K identifiers.
     78     ExternalLookup(externalLookup) {
     79 
     80   // Populate the identifier table with info about keywords for the current
     81   // language.
     82   AddKeywords(LangOpts);
     83 
     84 
     85   // Add the '_experimental_modules_import' contextual keyword.
     86   get("import").setModulesImport(true);
     87 }
     88 
     89 //===----------------------------------------------------------------------===//
     90 // Language Keyword Implementation
     91 //===----------------------------------------------------------------------===//
     92 
     93 // Constants for TokenKinds.def
     94 namespace {
     95   enum {
     96     KEYC99 = 0x1,
     97     KEYCXX = 0x2,
     98     KEYCXX11 = 0x4,
     99     KEYGNU = 0x8,
    100     KEYMS = 0x10,
    101     BOOLSUPPORT = 0x20,
    102     KEYALTIVEC = 0x40,
    103     KEYNOCXX = 0x80,
    104     KEYBORLAND = 0x100,
    105     KEYOPENCL = 0x200,
    106     KEYC11 = 0x400,
    107     KEYARC = 0x800,
    108     KEYNOMS18 = 0x01000,
    109     KEYNOOPENCL = 0x02000,
    110     WCHARSUPPORT = 0x04000,
    111     HALFSUPPORT = 0x08000,
    112     KEYCONCEPTS = 0x10000,
    113     KEYOBJC2    = 0x20000,
    114     KEYZVECTOR  = 0x40000,
    115     KEYCOROUTINES = 0x80000,
    116     KEYALL = (0xfffff & ~KEYNOMS18 &
    117               ~KEYNOOPENCL) // KEYNOMS18 and KEYNOOPENCL are used to exclude.
    118   };
    119 
    120   /// \brief How a keyword is treated in the selected standard.
    121   enum KeywordStatus {
    122     KS_Disabled,    // Disabled
    123     KS_Extension,   // Is an extension
    124     KS_Enabled,     // Enabled
    125     KS_Future       // Is a keyword in future standard
    126   };
    127 }
    128 
    129 /// \brief Translates flags as specified in TokenKinds.def into keyword status
    130 /// in the given language standard.
    131 static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
    132                                       unsigned Flags) {
    133   if (Flags == KEYALL) return KS_Enabled;
    134   if (LangOpts.CPlusPlus && (Flags & KEYCXX)) return KS_Enabled;
    135   if (LangOpts.CPlusPlus11 && (Flags & KEYCXX11)) return KS_Enabled;
    136   if (LangOpts.C99 && (Flags & KEYC99)) return KS_Enabled;
    137   if (LangOpts.GNUKeywords && (Flags & KEYGNU)) return KS_Extension;
    138   if (LangOpts.MicrosoftExt && (Flags & KEYMS)) return KS_Extension;
    139   if (LangOpts.Borland && (Flags & KEYBORLAND)) return KS_Extension;
    140   if (LangOpts.Bool && (Flags & BOOLSUPPORT)) return KS_Enabled;
    141   if (LangOpts.Half && (Flags & HALFSUPPORT)) return KS_Enabled;
    142   if (LangOpts.WChar && (Flags & WCHARSUPPORT)) return KS_Enabled;
    143   if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) return KS_Enabled;
    144   if (LangOpts.OpenCL && (Flags & KEYOPENCL)) return KS_Enabled;
    145   if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) return KS_Enabled;
    146   if (LangOpts.C11 && (Flags & KEYC11)) return KS_Enabled;
    147   // We treat bridge casts as objective-C keywords so we can warn on them
    148   // in non-arc mode.
    149   if (LangOpts.ObjC2 && (Flags & KEYARC)) return KS_Enabled;
    150   if (LangOpts.ConceptsTS && (Flags & KEYCONCEPTS)) return KS_Enabled;
    151   if (LangOpts.ObjC2 && (Flags & KEYOBJC2)) return KS_Enabled;
    152   if (LangOpts.Coroutines && (Flags & KEYCOROUTINES)) return KS_Enabled;
    153   if (LangOpts.CPlusPlus && (Flags & KEYCXX11)) return KS_Future;
    154   return KS_Disabled;
    155 }
    156 
    157 /// AddKeyword - This method is used to associate a token ID with specific
    158 /// identifiers because they are language keywords.  This causes the lexer to
    159 /// automatically map matching identifiers to specialized token codes.
    160 static void AddKeyword(StringRef Keyword,
    161                        tok::TokenKind TokenCode, unsigned Flags,
    162                        const LangOptions &LangOpts, IdentifierTable &Table) {
    163   KeywordStatus AddResult = getKeywordStatus(LangOpts, Flags);
    164 
    165   // Don't add this keyword under MSVCCompat.
    166   if (LangOpts.MSVCCompat && (Flags & KEYNOMS18) &&
    167       !LangOpts.isCompatibleWithMSVC(LangOptions::MSVC2015))
    168     return;
    169 
    170   // Don't add this keyword under OpenCL.
    171   if (LangOpts.OpenCL && (Flags & KEYNOOPENCL))
    172     return;
    173 
    174   // Don't add this keyword if disabled in this language.
    175   if (AddResult == KS_Disabled) return;
    176 
    177   IdentifierInfo &Info =
    178       Table.get(Keyword, AddResult == KS_Future ? tok::identifier : TokenCode);
    179   Info.setIsExtensionToken(AddResult == KS_Extension);
    180   Info.setIsFutureCompatKeyword(AddResult == KS_Future);
    181 }
    182 
    183 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
    184 /// representations.
    185 static void AddCXXOperatorKeyword(StringRef Keyword,
    186                                   tok::TokenKind TokenCode,
    187                                   IdentifierTable &Table) {
    188   IdentifierInfo &Info = Table.get(Keyword, TokenCode);
    189   Info.setIsCPlusPlusOperatorKeyword();
    190 }
    191 
    192 /// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
    193 /// or "property".
    194 static void AddObjCKeyword(StringRef Name,
    195                            tok::ObjCKeywordKind ObjCID,
    196                            IdentifierTable &Table) {
    197   Table.get(Name).setObjCKeywordID(ObjCID);
    198 }
    199 
    200 /// AddKeywords - Add all keywords to the symbol table.
    201 ///
    202 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
    203   // Add keywords and tokens for the current language.
    204 #define KEYWORD(NAME, FLAGS) \
    205   AddKeyword(StringRef(#NAME), tok::kw_ ## NAME,  \
    206              FLAGS, LangOpts, *this);
    207 #define ALIAS(NAME, TOK, FLAGS) \
    208   AddKeyword(StringRef(NAME), tok::kw_ ## TOK,  \
    209              FLAGS, LangOpts, *this);
    210 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
    211   if (LangOpts.CXXOperatorNames)          \
    212     AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
    213 #define OBJC1_AT_KEYWORD(NAME) \
    214   if (LangOpts.ObjC1)          \
    215     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
    216 #define OBJC2_AT_KEYWORD(NAME) \
    217   if (LangOpts.ObjC2)          \
    218     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
    219 #define TESTING_KEYWORD(NAME, FLAGS)
    220 #include "clang/Basic/TokenKinds.def"
    221 
    222   if (LangOpts.ParseUnknownAnytype)
    223     AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
    224                LangOpts, *this);
    225 
    226   if (LangOpts.DeclSpecKeyword)
    227     AddKeyword("__declspec", tok::kw___declspec, KEYALL, LangOpts, *this);
    228 }
    229 
    230 /// \brief Checks if the specified token kind represents a keyword in the
    231 /// specified language.
    232 /// \returns Status of the keyword in the language.
    233 static KeywordStatus getTokenKwStatus(const LangOptions &LangOpts,
    234                                       tok::TokenKind K) {
    235   switch (K) {
    236 #define KEYWORD(NAME, FLAGS) \
    237   case tok::kw_##NAME: return getKeywordStatus(LangOpts, FLAGS);
    238 #include "clang/Basic/TokenKinds.def"
    239   default: return KS_Disabled;
    240   }
    241 }
    242 
    243 /// \brief Returns true if the identifier represents a keyword in the
    244 /// specified language.
    245 bool IdentifierInfo::isKeyword(const LangOptions &LangOpts) {
    246   switch (getTokenKwStatus(LangOpts, getTokenID())) {
    247   case KS_Enabled:
    248   case KS_Extension:
    249     return true;
    250   default:
    251     return false;
    252   }
    253 }
    254 
    255 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
    256   // We use a perfect hash function here involving the length of the keyword,
    257   // the first and third character.  For preprocessor ID's there are no
    258   // collisions (if there were, the switch below would complain about duplicate
    259   // case values).  Note that this depends on 'if' being null terminated.
    260 
    261 #define HASH(LEN, FIRST, THIRD) \
    262   (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
    263 #define CASE(LEN, FIRST, THIRD, NAME) \
    264   case HASH(LEN, FIRST, THIRD): \
    265     return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
    266 
    267   unsigned Len = getLength();
    268   if (Len < 2) return tok::pp_not_keyword;
    269   const char *Name = getNameStart();
    270   switch (HASH(Len, Name[0], Name[2])) {
    271   default: return tok::pp_not_keyword;
    272   CASE( 2, 'i', '\0', if);
    273   CASE( 4, 'e', 'i', elif);
    274   CASE( 4, 'e', 's', else);
    275   CASE( 4, 'l', 'n', line);
    276   CASE( 4, 's', 'c', sccs);
    277   CASE( 5, 'e', 'd', endif);
    278   CASE( 5, 'e', 'r', error);
    279   CASE( 5, 'i', 'e', ident);
    280   CASE( 5, 'i', 'd', ifdef);
    281   CASE( 5, 'u', 'd', undef);
    282 
    283   CASE( 6, 'a', 's', assert);
    284   CASE( 6, 'd', 'f', define);
    285   CASE( 6, 'i', 'n', ifndef);
    286   CASE( 6, 'i', 'p', import);
    287   CASE( 6, 'p', 'a', pragma);
    288 
    289   CASE( 7, 'd', 'f', defined);
    290   CASE( 7, 'i', 'c', include);
    291   CASE( 7, 'w', 'r', warning);
    292 
    293   CASE( 8, 'u', 'a', unassert);
    294   CASE(12, 'i', 'c', include_next);
    295 
    296   CASE(14, '_', 'p', __public_macro);
    297 
    298   CASE(15, '_', 'p', __private_macro);
    299 
    300   CASE(16, '_', 'i', __include_macros);
    301 #undef CASE
    302 #undef HASH
    303   }
    304 }
    305 
    306 //===----------------------------------------------------------------------===//
    307 // Stats Implementation
    308 //===----------------------------------------------------------------------===//
    309 
    310 /// PrintStats - Print statistics about how well the identifier table is doing
    311 /// at hashing identifiers.
    312 void IdentifierTable::PrintStats() const {
    313   unsigned NumBuckets = HashTable.getNumBuckets();
    314   unsigned NumIdentifiers = HashTable.getNumItems();
    315   unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
    316   unsigned AverageIdentifierSize = 0;
    317   unsigned MaxIdentifierLength = 0;
    318 
    319   // TODO: Figure out maximum times an identifier had to probe for -stats.
    320   for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
    321        I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
    322     unsigned IdLen = I->getKeyLength();
    323     AverageIdentifierSize += IdLen;
    324     if (MaxIdentifierLength < IdLen)
    325       MaxIdentifierLength = IdLen;
    326   }
    327 
    328   fprintf(stderr, "\n*** Identifier Table Stats:\n");
    329   fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
    330   fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
    331   fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
    332           NumIdentifiers/(double)NumBuckets);
    333   fprintf(stderr, "Ave identifier length: %f\n",
    334           (AverageIdentifierSize/(double)NumIdentifiers));
    335   fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
    336 
    337   // Compute statistics about the memory allocated for identifiers.
    338   HashTable.getAllocator().PrintStats();
    339 }
    340 
    341 //===----------------------------------------------------------------------===//
    342 // SelectorTable Implementation
    343 //===----------------------------------------------------------------------===//
    344 
    345 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
    346   return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
    347 }
    348 
    349 namespace clang {
    350 /// MultiKeywordSelector - One of these variable length records is kept for each
    351 /// selector containing more than one keyword. We use a folding set
    352 /// to unique aggregate names (keyword selectors in ObjC parlance). Access to
    353 /// this class is provided strictly through Selector.
    354 class MultiKeywordSelector
    355   : public DeclarationNameExtra, public llvm::FoldingSetNode {
    356   MultiKeywordSelector(unsigned nKeys) {
    357     ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
    358   }
    359 public:
    360   // Constructor for keyword selectors.
    361   MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV) {
    362     assert((nKeys > 1) && "not a multi-keyword selector");
    363     ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
    364 
    365     // Fill in the trailing keyword array.
    366     IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1);
    367     for (unsigned i = 0; i != nKeys; ++i)
    368       KeyInfo[i] = IIV[i];
    369   }
    370 
    371   // getName - Derive the full selector name and return it.
    372   std::string getName() const;
    373 
    374   unsigned getNumArgs() const { return ExtraKindOrNumArgs - NUM_EXTRA_KINDS; }
    375 
    376   typedef IdentifierInfo *const *keyword_iterator;
    377   keyword_iterator keyword_begin() const {
    378     return reinterpret_cast<keyword_iterator>(this+1);
    379   }
    380   keyword_iterator keyword_end() const {
    381     return keyword_begin()+getNumArgs();
    382   }
    383   IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
    384     assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
    385     return keyword_begin()[i];
    386   }
    387   static void Profile(llvm::FoldingSetNodeID &ID,
    388                       keyword_iterator ArgTys, unsigned NumArgs) {
    389     ID.AddInteger(NumArgs);
    390     for (unsigned i = 0; i != NumArgs; ++i)
    391       ID.AddPointer(ArgTys[i]);
    392   }
    393   void Profile(llvm::FoldingSetNodeID &ID) {
    394     Profile(ID, keyword_begin(), getNumArgs());
    395   }
    396 };
    397 } // end namespace clang.
    398 
    399 unsigned Selector::getNumArgs() const {
    400   unsigned IIF = getIdentifierInfoFlag();
    401   if (IIF <= ZeroArg)
    402     return 0;
    403   if (IIF == OneArg)
    404     return 1;
    405   // We point to a MultiKeywordSelector.
    406   MultiKeywordSelector *SI = getMultiKeywordSelector();
    407   return SI->getNumArgs();
    408 }
    409 
    410 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
    411   if (getIdentifierInfoFlag() < MultiArg) {
    412     assert(argIndex == 0 && "illegal keyword index");
    413     return getAsIdentifierInfo();
    414   }
    415   // We point to a MultiKeywordSelector.
    416   MultiKeywordSelector *SI = getMultiKeywordSelector();
    417   return SI->getIdentifierInfoForSlot(argIndex);
    418 }
    419 
    420 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
    421   IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
    422   return II? II->getName() : StringRef();
    423 }
    424 
    425 std::string MultiKeywordSelector::getName() const {
    426   SmallString<256> Str;
    427   llvm::raw_svector_ostream OS(Str);
    428   for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
    429     if (*I)
    430       OS << (*I)->getName();
    431     OS << ':';
    432   }
    433 
    434   return OS.str();
    435 }
    436 
    437 std::string Selector::getAsString() const {
    438   if (InfoPtr == 0)
    439     return "<null selector>";
    440 
    441   if (getIdentifierInfoFlag() < MultiArg) {
    442     IdentifierInfo *II = getAsIdentifierInfo();
    443 
    444     // If the number of arguments is 0 then II is guaranteed to not be null.
    445     if (getNumArgs() == 0)
    446       return II->getName();
    447 
    448     if (!II)
    449       return ":";
    450 
    451     return II->getName().str() + ":";
    452   }
    453 
    454   // We have a multiple keyword selector.
    455   return getMultiKeywordSelector()->getName();
    456 }
    457 
    458 void Selector::print(llvm::raw_ostream &OS) const {
    459   OS << getAsString();
    460 }
    461 
    462 /// Interpreting the given string using the normal CamelCase
    463 /// conventions, determine whether the given string starts with the
    464 /// given "word", which is assumed to end in a lowercase letter.
    465 static bool startsWithWord(StringRef name, StringRef word) {
    466   if (name.size() < word.size()) return false;
    467   return ((name.size() == word.size() || !isLowercase(name[word.size()])) &&
    468           name.startswith(word));
    469 }
    470 
    471 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
    472   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
    473   if (!first) return OMF_None;
    474 
    475   StringRef name = first->getName();
    476   if (sel.isUnarySelector()) {
    477     if (name == "autorelease") return OMF_autorelease;
    478     if (name == "dealloc") return OMF_dealloc;
    479     if (name == "finalize") return OMF_finalize;
    480     if (name == "release") return OMF_release;
    481     if (name == "retain") return OMF_retain;
    482     if (name == "retainCount") return OMF_retainCount;
    483     if (name == "self") return OMF_self;
    484     if (name == "initialize") return OMF_initialize;
    485   }
    486 
    487   if (name == "performSelector") return OMF_performSelector;
    488 
    489   // The other method families may begin with a prefix of underscores.
    490   while (!name.empty() && name.front() == '_')
    491     name = name.substr(1);
    492 
    493   if (name.empty()) return OMF_None;
    494   switch (name.front()) {
    495   case 'a':
    496     if (startsWithWord(name, "alloc")) return OMF_alloc;
    497     break;
    498   case 'c':
    499     if (startsWithWord(name, "copy")) return OMF_copy;
    500     break;
    501   case 'i':
    502     if (startsWithWord(name, "init")) return OMF_init;
    503     break;
    504   case 'm':
    505     if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
    506     break;
    507   case 'n':
    508     if (startsWithWord(name, "new")) return OMF_new;
    509     break;
    510   default:
    511     break;
    512   }
    513 
    514   return OMF_None;
    515 }
    516 
    517 ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
    518   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
    519   if (!first) return OIT_None;
    520 
    521   StringRef name = first->getName();
    522 
    523   if (name.empty()) return OIT_None;
    524   switch (name.front()) {
    525     case 'a':
    526       if (startsWithWord(name, "array")) return OIT_Array;
    527       break;
    528     case 'd':
    529       if (startsWithWord(name, "default")) return OIT_ReturnsSelf;
    530       if (startsWithWord(name, "dictionary")) return OIT_Dictionary;
    531       break;
    532     case 's':
    533       if (startsWithWord(name, "shared")) return OIT_ReturnsSelf;
    534       if (startsWithWord(name, "standard")) return OIT_Singleton;
    535     case 'i':
    536       if (startsWithWord(name, "init")) return OIT_Init;
    537     default:
    538       break;
    539   }
    540   return OIT_None;
    541 }
    542 
    543 ObjCStringFormatFamily Selector::getStringFormatFamilyImpl(Selector sel) {
    544   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
    545   if (!first) return SFF_None;
    546 
    547   StringRef name = first->getName();
    548 
    549   switch (name.front()) {
    550     case 'a':
    551       if (name == "appendFormat") return SFF_NSString;
    552       break;
    553 
    554     case 'i':
    555       if (name == "initWithFormat") return SFF_NSString;
    556       break;
    557 
    558     case 'l':
    559       if (name == "localizedStringWithFormat") return SFF_NSString;
    560       break;
    561 
    562     case 's':
    563       if (name == "stringByAppendingFormat" ||
    564           name == "stringWithFormat") return SFF_NSString;
    565       break;
    566   }
    567   return SFF_None;
    568 }
    569 
    570 namespace {
    571   struct SelectorTableImpl {
    572     llvm::FoldingSet<MultiKeywordSelector> Table;
    573     llvm::BumpPtrAllocator Allocator;
    574   };
    575 } // end anonymous namespace.
    576 
    577 static SelectorTableImpl &getSelectorTableImpl(void *P) {
    578   return *static_cast<SelectorTableImpl*>(P);
    579 }
    580 
    581 SmallString<64>
    582 SelectorTable::constructSetterName(StringRef Name) {
    583   SmallString<64> SetterName("set");
    584   SetterName += Name;
    585   SetterName[3] = toUppercase(SetterName[3]);
    586   return SetterName;
    587 }
    588 
    589 Selector
    590 SelectorTable::constructSetterSelector(IdentifierTable &Idents,
    591                                        SelectorTable &SelTable,
    592                                        const IdentifierInfo *Name) {
    593   IdentifierInfo *SetterName =
    594     &Idents.get(constructSetterName(Name->getName()));
    595   return SelTable.getUnarySelector(SetterName);
    596 }
    597 
    598 size_t SelectorTable::getTotalMemory() const {
    599   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
    600   return SelTabImpl.Allocator.getTotalMemory();
    601 }
    602 
    603 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
    604   if (nKeys < 2)
    605     return Selector(IIV[0], nKeys);
    606 
    607   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
    608 
    609   // Unique selector, to guarantee there is one per name.
    610   llvm::FoldingSetNodeID ID;
    611   MultiKeywordSelector::Profile(ID, IIV, nKeys);
    612 
    613   void *InsertPos = nullptr;
    614   if (MultiKeywordSelector *SI =
    615         SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
    616     return Selector(SI);
    617 
    618   // MultiKeywordSelector objects are not allocated with new because they have a
    619   // variable size array (for parameter types) at the end of them.
    620   unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
    621   MultiKeywordSelector *SI =
    622     (MultiKeywordSelector*)SelTabImpl.Allocator.Allocate(Size,
    623                                          llvm::alignOf<MultiKeywordSelector>());
    624   new (SI) MultiKeywordSelector(nKeys, IIV);
    625   SelTabImpl.Table.InsertNode(SI, InsertPos);
    626   return Selector(SI);
    627 }
    628 
    629 SelectorTable::SelectorTable() {
    630   Impl = new SelectorTableImpl();
    631 }
    632 
    633 SelectorTable::~SelectorTable() {
    634   delete &getSelectorTableImpl(Impl);
    635 }
    636 
    637 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
    638   switch (Operator) {
    639   case OO_None:
    640   case NUM_OVERLOADED_OPERATORS:
    641     return nullptr;
    642 
    643 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
    644   case OO_##Name: return Spelling;
    645 #include "clang/Basic/OperatorKinds.def"
    646   }
    647 
    648   llvm_unreachable("Invalid OverloadedOperatorKind!");
    649 }
    650 
    651 StringRef clang::getNullabilitySpelling(NullabilityKind kind,
    652                                         bool isContextSensitive) {
    653   switch (kind) {
    654   case NullabilityKind::NonNull:
    655     return isContextSensitive ? "nonnull" : "_Nonnull";
    656 
    657   case NullabilityKind::Nullable:
    658     return isContextSensitive ? "nullable" : "_Nullable";
    659 
    660   case NullabilityKind::Unspecified:
    661     return isContextSensitive ? "null_unspecified" : "_Null_unspecified";
    662   }
    663   llvm_unreachable("Unknown nullability kind.");
    664 }
    665