clang/lib/Basic/IdentifierTable.cpp

   1 //===- IdentifierTable.cpp - Hash table for identifier lookup -------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the IdentifierInfo, IdentifierVisitor, and
  10 // IdentifierTable interfaces.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/Basic/IdentifierTable.h"
  15 #include "clang/Basic/CharInfo.h"
  16 #include "clang/Basic/DiagnosticLex.h"
  17 #include "clang/Basic/LangOptions.h"
  18 #include "clang/Basic/OperatorKinds.h"
  19 #include "clang/Basic/Specifiers.h"
  20 #include "clang/Basic/TargetBuiltins.h"
  21 #include "clang/Basic/TokenKinds.h"
  22 #include "llvm/ADT/DenseMapInfo.h"
  23 #include "llvm/ADT/FoldingSet.h"
  24 #include "llvm/ADT/SmallString.h"
  25 #include "llvm/ADT/StringMap.h"
  26 #include "llvm/ADT/StringRef.h"
  27 #include "llvm/Support/Allocator.h"
  28 #include "llvm/Support/raw_ostream.h"
  29 #include <cassert>
  30 #include <cstdio>
  31 #include <cstring>
  32 #include <string>
  33
  34 using namespace clang;
  35
  36 // A check to make sure the ObjCOrBuiltinID has sufficient room to store the
  37 // largest possible target/aux-target combination. If we exceed this, we likely
  38 // need to just change the ObjCOrBuiltinIDBits value in IdentifierTable.h.
  39 static_assert(2 * LargestBuiltinID < (2 << (ObjCOrBuiltinIDBits - 1)),
  40               "Insufficient ObjCOrBuiltinID Bits");
  41
  42 //===----------------------------------------------------------------------===//
  43 // IdentifierTable Implementation
  44 //===----------------------------------------------------------------------===//
  45
  46 IdentifierIterator::~IdentifierIterator() = default;
  47
  48 IdentifierInfoLookup::~IdentifierInfoLookup() = default;
  49
  50 namespace {
  51
  52 /// A simple identifier lookup iterator that represents an
  53 /// empty sequence of identifiers.
  54 class EmptyLookupIterator : public IdentifierIterator {
  55 public:
  56   StringRef Next() override { return StringRef(); }
  57 };
  58
  59 } // namespace
  60
  61 IdentifierIterator *IdentifierInfoLookup::getIdentifiers() {
  62   return new EmptyLookupIterator();
  63 }
  64
  65 IdentifierTable::IdentifierTable(IdentifierInfoLookup *ExternalLookup)
  66     : HashTable(8192), // Start with space for 8K identifiers.
  67       ExternalLookup(ExternalLookup) {}
  68
  69 IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
  70                                  IdentifierInfoLookup *ExternalLookup)
  71     : IdentifierTable(ExternalLookup) {
  72   // Populate the identifier table with info about keywords for the current
  73   // language.
  74   AddKeywords(LangOpts);
  75 }
  76
  77 //===----------------------------------------------------------------------===//
  78 // Language Keyword Implementation
  79 //===----------------------------------------------------------------------===//
  80
  81 // Constants for TokenKinds.def
  82 namespace {
  83
  84   enum TokenKey : unsigned {
  85     KEYC99        = 0x1,
  86     KEYCXX        = 0x2,
  87     KEYCXX11      = 0x4,
  88     KEYGNU        = 0x8,
  89     KEYMS         = 0x10,
  90     BOOLSUPPORT   = 0x20,
  91     KEYALTIVEC    = 0x40,
  92     KEYNOCXX      = 0x80,
  93     KEYBORLAND    = 0x100,
  94     KEYOPENCLC    = 0x200,
  95     KEYC23        = 0x400,
  96     KEYNOMS18     = 0x800,
  97     KEYNOOPENCL   = 0x1000,
  98     WCHARSUPPORT  = 0x2000,
  99     HALFSUPPORT   = 0x4000,
 100     CHAR8SUPPORT  = 0x8000,
 101     KEYOBJC       = 0x10000,
 102     KEYZVECTOR    = 0x20000,
 103     KEYCOROUTINES = 0x40000,
 104     KEYMODULES    = 0x80000,
 105     KEYCXX20      = 0x100000,
 106     KEYOPENCLCXX  = 0x200000,
 107     KEYMSCOMPAT   = 0x400000,
 108     KEYSYCL       = 0x800000,
 109     KEYCUDA       = 0x1000000,
 110     KEYHLSL       = 0x2000000,
 111     KEYMAX        = KEYHLSL, // The maximum key
 112     KEYALLCXX = KEYCXX | KEYCXX11 | KEYCXX20,
 113     KEYALL = (KEYMAX | (KEYMAX-1)) & ~KEYNOMS18 &
 114              ~KEYNOOPENCL // KEYNOMS18 and KEYNOOPENCL are used to exclude.
 115   };
 116
 117   /// How a keyword is treated in the selected standard. This enum is ordered
 118   /// intentionally so that the value that 'wins' is the most 'permissive'.
 119   enum KeywordStatus {
 120     KS_Unknown,     // Not yet calculated. Used when figuring out the status.
 121     KS_Disabled,    // Disabled
 122     KS_Future,      // Is a keyword in future standard
 123     KS_Extension,   // Is an extension
 124     KS_Enabled,     // Enabled
 125   };
 126
 127 } // namespace
 128
 129 // This works on a single TokenKey flag and checks the LangOpts to get the
 130 // KeywordStatus based exclusively on this flag, so that it can be merged in
 131 // getKeywordStatus. Most should be enabled/disabled, but some might imply
 132 // 'future' versions, or extensions. Returns 'unknown' unless this is KNOWN to
 133 // be disabled, and the calling function makes it 'disabled' if no other flag
 134 // changes it. This is necessary for the KEYNOCXX and KEYNOOPENCL flags.
 135 static KeywordStatus getKeywordStatusHelper(const LangOptions &LangOpts,
 136                                             TokenKey Flag) {
 137   // Flag is a single bit version of TokenKey (that is, not
 138   // KEYALL/KEYALLCXX/etc), so we can check with == throughout this function.
 139   assert((Flag & ~(Flag - 1)) == Flag && "Multiple bits set?");
 140
 141   switch (Flag) {
 142   case KEYC99:
 143     if (LangOpts.C99)
 144       return KS_Enabled;
 145     return !LangOpts.CPlusPlus ? KS_Future : KS_Unknown;
 146   case KEYC23:
 147     if (LangOpts.C23)
 148       return KS_Enabled;
 149     return !LangOpts.CPlusPlus ? KS_Future : KS_Unknown;
 150   case KEYCXX:
 151     return LangOpts.CPlusPlus ? KS_Enabled : KS_Unknown;
 152   case KEYCXX11:
 153     if (LangOpts.CPlusPlus11)
 154       return KS_Enabled;
 155     return LangOpts.CPlusPlus ? KS_Future : KS_Unknown;
 156   case KEYCXX20:
 157     if (LangOpts.CPlusPlus20)
 158       return KS_Enabled;
 159     return LangOpts.CPlusPlus ? KS_Future : KS_Unknown;
 160   case KEYGNU:
 161     return LangOpts.GNUKeywords ? KS_Extension : KS_Unknown;
 162   case KEYMS:
 163     return LangOpts.MicrosoftExt ? KS_Extension : KS_Unknown;
 164   case BOOLSUPPORT:
 165     if (LangOpts.Bool)      return KS_Enabled;
 166     return !LangOpts.CPlusPlus ? KS_Future : KS_Unknown;
 167   case KEYALTIVEC:
 168     return LangOpts.AltiVec ? KS_Enabled : KS_Unknown;
 169   case KEYBORLAND:
 170     return LangOpts.Borland ? KS_Extension : KS_Unknown;
 171   case KEYOPENCLC:
 172     return LangOpts.OpenCL && !LangOpts.OpenCLCPlusPlus ? KS_Enabled
 173                                                         : KS_Unknown;
 174   case WCHARSUPPORT:
 175     return LangOpts.WChar ? KS_Enabled : KS_Unknown;
 176   case HALFSUPPORT:
 177     return LangOpts.Half ? KS_Enabled : KS_Unknown;
 178   case CHAR8SUPPORT:
 179     if (LangOpts.Char8) return KS_Enabled;
 180     if (LangOpts.CPlusPlus20) return KS_Unknown;
 181     if (LangOpts.CPlusPlus) return KS_Future;
 182     return KS_Unknown;
 183   case KEYOBJC:
 184     // We treat bridge casts as objective-C keywords so we can warn on them
 185     // in non-arc mode.
 186     return LangOpts.ObjC ? KS_Enabled : KS_Unknown;
 187   case KEYZVECTOR:
 188     return LangOpts.ZVector ? KS_Enabled : KS_Unknown;
 189   case KEYCOROUTINES:
 190     return LangOpts.Coroutines ? KS_Enabled : KS_Unknown;
 191   case KEYMODULES:
 192     return KS_Unknown;
 193   case KEYOPENCLCXX:
 194     return LangOpts.OpenCLCPlusPlus ? KS_Enabled : KS_Unknown;
 195   case KEYMSCOMPAT:
 196     return LangOpts.MSVCCompat ? KS_Enabled : KS_Unknown;
 197   case KEYSYCL:
 198     return LangOpts.isSYCL() ? KS_Enabled : KS_Unknown;
 199   case KEYCUDA:
 200     return LangOpts.CUDA ? KS_Enabled : KS_Unknown;
 201   case KEYHLSL:
 202     return LangOpts.HLSL ? KS_Enabled : KS_Unknown;
 203   case KEYNOCXX:
 204     // This is enabled in all non-C++ modes, but might be enabled for other
 205     // reasons as well.
 206     return LangOpts.CPlusPlus ? KS_Unknown : KS_Enabled;
 207   case KEYNOOPENCL:
 208     // The disable behavior for this is handled in getKeywordStatus.
 209     return KS_Unknown;
 210   case KEYNOMS18:
 211     // The disable behavior for this is handled in getKeywordStatus.
 212     return KS_Unknown;
 213   default:
 214     llvm_unreachable("Unknown KeywordStatus flag");
 215   }
 216 }
 217
 218 /// Translates flags as specified in TokenKinds.def into keyword status
 219 /// in the given language standard.
 220 static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
 221                                       unsigned Flags) {
 222   // KEYALL means always enabled, so special case this one.
 223   if (Flags == KEYALL) return KS_Enabled;
 224   // These are tests that need to 'always win', as they are special in that they
 225   // disable based on certain conditions.
 226   if (LangOpts.OpenCL && (Flags & KEYNOOPENCL)) return KS_Disabled;
 227   if (LangOpts.MSVCCompat && (Flags & KEYNOMS18) &&
 228       !LangOpts.isCompatibleWithMSVC(LangOptions::MSVC2015))
 229     return KS_Disabled;
 230
 231   KeywordStatus CurStatus = KS_Unknown;
 232
 233   while (Flags != 0) {
 234     unsigned CurFlag = Flags & ~(Flags - 1);
 235     Flags = Flags & ~CurFlag;
 236     CurStatus = std::max(
 237         CurStatus,
 238         getKeywordStatusHelper(LangOpts, static_cast<TokenKey>(CurFlag)));
 239   }
 240
 241   if (CurStatus == KS_Unknown)
 242     return KS_Disabled;
 243   return CurStatus;
 244 }
 245
 246 /// AddKeyword - This method is used to associate a token ID with specific
 247 /// identifiers because they are language keywords.  This causes the lexer to
 248 /// automatically map matching identifiers to specialized token codes.
 249 static void AddKeyword(StringRef Keyword,
 250                        tok::TokenKind TokenCode, unsigned Flags,
 251                        const LangOptions &LangOpts, IdentifierTable &Table) {
 252   KeywordStatus AddResult = getKeywordStatus(LangOpts, Flags);
 253
 254   // Don't add this keyword if disabled in this language.
 255   if (AddResult == KS_Disabled) return;
 256
 257   IdentifierInfo &Info =
 258       Table.get(Keyword, AddResult == KS_Future ? tok::identifier : TokenCode);
 259   Info.setIsExtensionToken(AddResult == KS_Extension);
 260   Info.setIsFutureCompatKeyword(AddResult == KS_Future);
 261 }
 262
 263 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
 264 /// representations.
 265 static void AddCXXOperatorKeyword(StringRef Keyword,
 266                                   tok::TokenKind TokenCode,
 267                                   IdentifierTable &Table) {
 268   IdentifierInfo &Info = Table.get(Keyword, TokenCode);
 269   Info.setIsCPlusPlusOperatorKeyword();
 270 }
 271
 272 /// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
 273 /// or "property".
 274 static void AddObjCKeyword(StringRef Name,
 275                            tok::ObjCKeywordKind ObjCID,
 276                            IdentifierTable &Table) {
 277   Table.get(Name).setObjCKeywordID(ObjCID);
 278 }
 279
 280 static void AddInterestingIdentifier(StringRef Name,
 281                                      tok::InterestingIdentifierKind BTID,
 282                                      IdentifierTable &Table) {
 283   // Don't add 'not_interesting' identifier.
 284   if (BTID != tok::not_interesting) {
 285     IdentifierInfo &Info = Table.get(Name, tok::identifier);
 286     Info.setInterestingIdentifierID(BTID);
 287   }
 288 }
 289
 290 /// AddKeywords - Add all keywords to the symbol table.
 291 ///
 292 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
 293   // Add keywords and tokens for the current language.
 294 #define KEYWORD(NAME, FLAGS) \
 295   AddKeyword(StringRef(#NAME), tok::kw_ ## NAME,  \
 296              FLAGS, LangOpts, *this);
 297 #define ALIAS(NAME, TOK, FLAGS) \
 298   AddKeyword(StringRef(NAME), tok::kw_ ## TOK,  \
 299              FLAGS, LangOpts, *this);
 300 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
 301   if (LangOpts.CXXOperatorNames)          \
 302     AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
 303 #define OBJC_AT_KEYWORD(NAME)  \
 304   if (LangOpts.ObjC)           \
 305     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
 306 #define INTERESTING_IDENTIFIER(NAME)                                           \
 307   AddInterestingIdentifier(StringRef(#NAME), tok::NAME, *this);
 308
 309 #define TESTING_KEYWORD(NAME, FLAGS)
 310 #include "clang/Basic/TokenKinds.def"
 311
 312   if (LangOpts.ParseUnknownAnytype)
 313     AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
 314                LangOpts, *this);
 315
 316   if (LangOpts.DeclSpecKeyword)
 317     AddKeyword("__declspec", tok::kw___declspec, KEYALL, LangOpts, *this);
 318
 319   if (LangOpts.IEEE128)
 320     AddKeyword("__ieee128", tok::kw___float128, KEYALL, LangOpts, *this);
 321
 322   // Add the 'import' contextual keyword.
 323   get("import").setModulesImport(true);
 324 }
 325
 326 /// Checks if the specified token kind represents a keyword in the
 327 /// specified language.
 328 /// \returns Status of the keyword in the language.
 329 static KeywordStatus getTokenKwStatus(const LangOptions &LangOpts,
 330                                       tok::TokenKind K) {
 331   switch (K) {
 332 #define KEYWORD(NAME, FLAGS) \
 333   case tok::kw_##NAME: return getKeywordStatus(LangOpts, FLAGS);
 334 #include "clang/Basic/TokenKinds.def"
 335   default: return KS_Disabled;
 336   }
 337 }
 338
 339 /// Returns true if the identifier represents a keyword in the
 340 /// specified language.
 341 bool IdentifierInfo::isKeyword(const LangOptions &LangOpts) const {
 342   switch (getTokenKwStatus(LangOpts, getTokenID())) {
 343   case KS_Enabled:
 344   case KS_Extension:
 345     return true;
 346   default:
 347     return false;
 348   }
 349 }
 350
 351 /// Returns true if the identifier represents a C++ keyword in the
 352 /// specified language.
 353 bool IdentifierInfo::isCPlusPlusKeyword(const LangOptions &LangOpts) const {
 354   if (!LangOpts.CPlusPlus || !isKeyword(LangOpts))
 355     return false;
 356   // This is a C++ keyword if this identifier is not a keyword when checked
 357   // using LangOptions without C++ support.
 358   LangOptions LangOptsNoCPP = LangOpts;
 359   LangOptsNoCPP.CPlusPlus = false;
 360   LangOptsNoCPP.CPlusPlus11 = false;
 361   LangOptsNoCPP.CPlusPlus20 = false;
 362   return !isKeyword(LangOptsNoCPP);
 363 }
 364
 365 ReservedIdentifierStatus
 366 IdentifierInfo::isReserved(const LangOptions &LangOpts) const {
 367   StringRef Name = getName();
 368
 369   // '_' is a reserved identifier, but its use is so common (e.g. to store
 370   // ignored values) that we don't warn on it.
 371   if (Name.size() <= 1)
 372     return ReservedIdentifierStatus::NotReserved;
 373
 374   // [lex.name] p3
 375   if (Name[0] == '_') {
 376
 377     // Each name that begins with an underscore followed by an uppercase letter
 378     // or another underscore is reserved.
 379     if (Name[1] == '_')
 380       return ReservedIdentifierStatus::StartsWithDoubleUnderscore;
 381
 382     if ('A' <= Name[1] && Name[1] <= 'Z')
 383       return ReservedIdentifierStatus::
 384           StartsWithUnderscoreFollowedByCapitalLetter;
 385
 386     // This is a bit misleading: it actually means it's only reserved if we're
 387     // at global scope because it starts with an underscore.
 388     return ReservedIdentifierStatus::StartsWithUnderscoreAtGlobalScope;
 389   }
 390
 391   // Each name that contains a double underscore (__) is reserved.
 392   if (LangOpts.CPlusPlus && Name.contains("__"))
 393     return ReservedIdentifierStatus::ContainsDoubleUnderscore;
 394
 395   return ReservedIdentifierStatus::NotReserved;
 396 }
 397
 398 ReservedLiteralSuffixIdStatus
 399 IdentifierInfo::isReservedLiteralSuffixId() const {
 400   StringRef Name = getName();
 401
 402   if (Name[0] != '_')
 403     return ReservedLiteralSuffixIdStatus::NotStartsWithUnderscore;
 404
 405   if (Name.contains("__"))
 406     return ReservedLiteralSuffixIdStatus::ContainsDoubleUnderscore;
 407
 408   return ReservedLiteralSuffixIdStatus::NotReserved;
 409 }
 410
 411 StringRef IdentifierInfo::deuglifiedName() const {
 412   StringRef Name = getName();
 413   if (Name.size() >= 2 && Name.front() == '_' &&
 414       (Name[1] == '_' || (Name[1] >= 'A' && Name[1] <= 'Z')))
 415     return Name.ltrim('_');
 416   return Name;
 417 }
 418
 419 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
 420   // We use a perfect hash function here involving the length of the keyword,
 421   // the first and third character.  For preprocessor ID's there are no
 422   // collisions (if there were, the switch below would complain about duplicate
 423   // case values).  Note that this depends on 'if' being null terminated.
 424
 425 #define HASH(LEN, FIRST, THIRD) \
 426   (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
 427 #define CASE(LEN, FIRST, THIRD, NAME) \
 428   case HASH(LEN, FIRST, THIRD): \
 429     return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
 430
 431   unsigned Len = getLength();
 432   if (Len < 2) return tok::pp_not_keyword;
 433   const char *Name = getNameStart();
 434   switch (HASH(Len, Name[0], Name[2])) {
 435   default: return tok::pp_not_keyword;
 436   CASE( 2, 'i', '\0', if);
 437   CASE( 4, 'e', 'i', elif);
 438   CASE( 4, 'e', 's', else);
 439   CASE( 4, 'l', 'n', line);
 440   CASE( 4, 's', 'c', sccs);
 441   CASE( 5, 'e', 'd', endif);
 442   CASE( 5, 'e', 'r', error);
 443   CASE( 5, 'i', 'e', ident);
 444   CASE( 5, 'i', 'd', ifdef);
 445   CASE( 5, 'u', 'd', undef);
 446
 447   CASE( 6, 'a', 's', assert);
 448   CASE( 6, 'd', 'f', define);
 449   CASE( 6, 'i', 'n', ifndef);
 450   CASE( 6, 'i', 'p', import);
 451   CASE( 6, 'p', 'a', pragma);
 452
 453   CASE( 7, 'd', 'f', defined);
 454   CASE( 7, 'e', 'i', elifdef);
 455   CASE( 7, 'i', 'c', include);
 456   CASE( 7, 'w', 'r', warning);
 457
 458   CASE( 8, 'e', 'i', elifndef);
 459   CASE( 8, 'u', 'a', unassert);
 460   CASE(12, 'i', 'c', include_next);
 461
 462   CASE(14, '_', 'p', __public_macro);
 463
 464   CASE(15, '_', 'p', __private_macro);
 465
 466   CASE(16, '_', 'i', __include_macros);
 467 #undef CASE
 468 #undef HASH
 469   }
 470 }
 471
 472 //===----------------------------------------------------------------------===//
 473 // Stats Implementation
 474 //===----------------------------------------------------------------------===//
 475
 476 /// PrintStats - Print statistics about how well the identifier table is doing
 477 /// at hashing identifiers.
 478 void IdentifierTable::PrintStats() const {
 479   unsigned NumBuckets = HashTable.getNumBuckets();
 480   unsigned NumIdentifiers = HashTable.getNumItems();
 481   unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
 482   unsigned AverageIdentifierSize = 0;
 483   unsigned MaxIdentifierLength = 0;
 484
 485   // TODO: Figure out maximum times an identifier had to probe for -stats.
 486   for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
 487        I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
 488     unsigned IdLen = I->getKeyLength();
 489     AverageIdentifierSize += IdLen;
 490     if (MaxIdentifierLength < IdLen)
 491       MaxIdentifierLength = IdLen;
 492   }
 493
 494   fprintf(stderr, "\n*** Identifier Table Stats:\n");
 495   fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
 496   fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
 497   fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
 498           NumIdentifiers/(double)NumBuckets);
 499   fprintf(stderr, "Ave identifier length: %f\n",
 500           (AverageIdentifierSize/(double)NumIdentifiers));
 501   fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
 502
 503   // Compute statistics about the memory allocated for identifiers.
 504   HashTable.getAllocator().PrintStats();
 505 }
 506
 507 //===----------------------------------------------------------------------===//
 508 // SelectorTable Implementation
 509 //===----------------------------------------------------------------------===//
 510
 511 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
 512   return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
 513 }
 514
 515 bool Selector::isKeywordSelector(ArrayRef<StringRef> Names) const {
 516   assert(!Names.empty() && "must have >= 1 selector slots");
 517   if (getNumArgs() != Names.size())
 518     return false;
 519   for (unsigned I = 0, E = Names.size(); I != E; ++I) {
 520     if (getNameForSlot(I) != Names[I])
 521       return false;
 522   }
 523   return true;
 524 }
 525
 526 bool Selector::isUnarySelector(StringRef Name) const {
 527   return isUnarySelector() && getNameForSlot(0) == Name;
 528 }
 529
 530 unsigned Selector::getNumArgs() const {
 531   unsigned IIF = getIdentifierInfoFlag();
 532   if (IIF <= ZeroArg)
 533     return 0;
 534   if (IIF == OneArg)
 535     return 1;
 536   // We point to a MultiKeywordSelector.
 537   MultiKeywordSelector *SI = getMultiKeywordSelector();
 538   return SI->getNumArgs();
 539 }
 540
 541 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
 542   if (getIdentifierInfoFlag() < MultiArg) {
 543     assert(argIndex == 0 && "illegal keyword index");
 544     return getAsIdentifierInfo();
 545   }
 546
 547   // We point to a MultiKeywordSelector.
 548   MultiKeywordSelector *SI = getMultiKeywordSelector();
 549   return SI->getIdentifierInfoForSlot(argIndex);
 550 }
 551
 552 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
 553   IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
 554   return II ? II->getName() : StringRef();
 555 }
 556
 557 std::string MultiKeywordSelector::getName() const {
 558   SmallString<256> Str;
 559   llvm::raw_svector_ostream OS(Str);
 560   for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
 561     if (*I)
 562       OS << (*I)->getName();
 563     OS << ':';
 564   }
 565
 566   return std::string(OS.str());
 567 }
 568
 569 std::string Selector::getAsString() const {
 570   if (isNull())
 571     return "<null selector>";
 572
 573   if (getIdentifierInfoFlag() < MultiArg) {
 574     IdentifierInfo *II = getAsIdentifierInfo();
 575
 576     if (getNumArgs() == 0) {
 577       assert(II && "If the number of arguments is 0 then II is guaranteed to "
 578                    "not be null.");
 579       return std::string(II->getName());
 580     }
 581
 582     if (!II)
 583       return ":";
 584
 585     return II->getName().str() + ":";
 586   }
 587
 588   // We have a multiple keyword selector.
 589   return getMultiKeywordSelector()->getName();
 590 }
 591
 592 void Selector::print(llvm::raw_ostream &OS) const {
 593   OS << getAsString();
 594 }
 595
 596 LLVM_DUMP_METHOD void Selector::dump() const { print(llvm::errs()); }
 597
 598 /// Interpreting the given string using the normal CamelCase
 599 /// conventions, determine whether the given string starts with the
 600 /// given "word", which is assumed to end in a lowercase letter.
 601 static bool startsWithWord(StringRef name, StringRef word) {
 602   if (name.size() < word.size()) return false;
 603   return ((name.size() == word.size() || !isLowercase(name[word.size()])) &&
 604           name.startswith(word));
 605 }
 606
 607 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
 608   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
 609   if (!first) return OMF_None;
 610
 611   StringRef name = first->getName();
 612   if (sel.isUnarySelector()) {
 613     if (name == "autorelease") return OMF_autorelease;
 614     if (name == "dealloc") return OMF_dealloc;
 615     if (name == "finalize") return OMF_finalize;
 616     if (name == "release") return OMF_release;
 617     if (name == "retain") return OMF_retain;
 618     if (name == "retainCount") return OMF_retainCount;
 619     if (name == "self") return OMF_self;
 620     if (name == "initialize") return OMF_initialize;
 621   }
 622
 623   if (name == "performSelector" || name == "performSelectorInBackground" ||
 624       name == "performSelectorOnMainThread")
 625     return OMF_performSelector;
 626
 627   // The other method families may begin with a prefix of underscores.
 628   while (!name.empty() && name.front() == '_')
 629     name = name.substr(1);
 630
 631   if (name.empty()) return OMF_None;
 632   switch (name.front()) {
 633   case 'a':
 634     if (startsWithWord(name, "alloc")) return OMF_alloc;
 635     break;
 636   case 'c':
 637     if (startsWithWord(name, "copy")) return OMF_copy;
 638     break;
 639   case 'i':
 640     if (startsWithWord(name, "init")) return OMF_init;
 641     break;
 642   case 'm':
 643     if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
 644     break;
 645   case 'n':
 646     if (startsWithWord(name, "new")) return OMF_new;
 647     break;
 648   default:
 649     break;
 650   }
 651
 652   return OMF_None;
 653 }
 654
 655 ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
 656   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
 657   if (!first) return OIT_None;
 658
 659   StringRef name = first->getName();
 660
 661   if (name.empty()) return OIT_None;
 662   switch (name.front()) {
 663     case 'a':
 664       if (startsWithWord(name, "array")) return OIT_Array;
 665       break;
 666     case 'd':
 667       if (startsWithWord(name, "default")) return OIT_ReturnsSelf;
 668       if (startsWithWord(name, "dictionary")) return OIT_Dictionary;
 669       break;
 670     case 's':
 671       if (startsWithWord(name, "shared")) return OIT_ReturnsSelf;
 672       if (startsWithWord(name, "standard")) return OIT_Singleton;
 673       break;
 674     case 'i':
 675       if (startsWithWord(name, "init")) return OIT_Init;
 676       break;
 677     default:
 678       break;
 679   }
 680   return OIT_None;
 681 }
 682
 683 ObjCStringFormatFamily Selector::getStringFormatFamilyImpl(Selector sel) {
 684   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
 685   if (!first) return SFF_None;
 686
 687   StringRef name = first->getName();
 688
 689   switch (name.front()) {
 690     case 'a':
 691       if (name == "appendFormat") return SFF_NSString;
 692       break;
 693
 694     case 'i':
 695       if (name == "initWithFormat") return SFF_NSString;
 696       break;
 697
 698     case 'l':
 699       if (name == "localizedStringWithFormat") return SFF_NSString;
 700       break;
 701
 702     case 's':
 703       if (name == "stringByAppendingFormat" ||
 704           name == "stringWithFormat") return SFF_NSString;
 705       break;
 706   }
 707   return SFF_None;
 708 }
 709
 710 namespace {
 711
 712 struct SelectorTableImpl {
 713   llvm::FoldingSet<MultiKeywordSelector> Table;
 714   llvm::BumpPtrAllocator Allocator;
 715 };
 716
 717 } // namespace
 718
 719 static SelectorTableImpl &getSelectorTableImpl(void *P) {
 720   return *static_cast<SelectorTableImpl*>(P);
 721 }
 722
 723 SmallString<64>
 724 SelectorTable::constructSetterName(StringRef Name) {
 725   SmallString<64> SetterName("set");
 726   SetterName += Name;
 727   SetterName[3] = toUppercase(SetterName[3]);
 728   return SetterName;
 729 }
 730
 731 Selector
 732 SelectorTable::constructSetterSelector(IdentifierTable &Idents,
 733                                        SelectorTable &SelTable,
 734                                        const IdentifierInfo *Name) {
 735   IdentifierInfo *SetterName =
 736     &Idents.get(constructSetterName(Name->getName()));
 737   return SelTable.getUnarySelector(SetterName);
 738 }
 739
 740 std::string SelectorTable::getPropertyNameFromSetterSelector(Selector Sel) {
 741   StringRef Name = Sel.getNameForSlot(0);
 742   assert(Name.startswith("set") && "invalid setter name");
 743   return (Twine(toLowercase(Name[3])) + Name.drop_front(4)).str();
 744 }
 745
 746 size_t SelectorTable::getTotalMemory() const {
 747   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
 748   return SelTabImpl.Allocator.getTotalMemory();
 749 }
 750
 751 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
 752   if (nKeys < 2)
 753     return Selector(IIV[0], nKeys);
 754
 755   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
 756
 757   // Unique selector, to guarantee there is one per name.
 758   llvm::FoldingSetNodeID ID;
 759   MultiKeywordSelector::Profile(ID, IIV, nKeys);
 760
 761   void *InsertPos = nullptr;
 762   if (MultiKeywordSelector *SI =
 763         SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
 764     return Selector(SI);
 765
 766   // MultiKeywordSelector objects are not allocated with new because they have a
 767   // variable size array (for parameter types) at the end of them.
 768   unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
 769   MultiKeywordSelector *SI =
 770       (MultiKeywordSelector *)SelTabImpl.Allocator.Allocate(
 771           Size, alignof(MultiKeywordSelector));
 772   new (SI) MultiKeywordSelector(nKeys, IIV);
 773   SelTabImpl.Table.InsertNode(SI, InsertPos);
 774   return Selector(SI);
 775 }
 776
 777 SelectorTable::SelectorTable() {
 778   Impl = new SelectorTableImpl();
 779 }
 780
 781 SelectorTable::~SelectorTable() {
 782   delete &getSelectorTableImpl(Impl);
 783 }
 784
 785 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
 786   switch (Operator) {
 787   case OO_None:
 788   case NUM_OVERLOADED_OPERATORS:
 789     return nullptr;
 790
 791 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
 792   case OO_##Name: return Spelling;
 793 #include "clang/Basic/OperatorKinds.def"
 794   }
 795
 796   llvm_unreachable("Invalid OverloadedOperatorKind!");
 797 }
 798
 799 StringRef clang::getNullabilitySpelling(NullabilityKind kind,
 800                                         bool isContextSensitive) {
 801   switch (kind) {
 802   case NullabilityKind::NonNull:
 803     return isContextSensitive ? "nonnull" : "_Nonnull";
 804
 805   case NullabilityKind::Nullable:
 806     return isContextSensitive ? "nullable" : "_Nullable";
 807
 808   case NullabilityKind::NullableResult:
 809     assert(!isContextSensitive &&
 810            "_Nullable_result isn't supported as context-sensitive keyword");
 811     return "_Nullable_result";
 812
 813   case NullabilityKind::Unspecified:
 814     return isContextSensitive ? "null_unspecified" : "_Null_unspecified";
 815   }
 816   llvm_unreachable("Unknown nullability kind.");
 817 }
 818
 819 llvm::raw_ostream &clang::operator<<(llvm::raw_ostream &OS,
 820                                      NullabilityKind NK) {
 821   switch (NK) {
 822   case NullabilityKind::NonNull:
 823     return OS << "NonNull";
 824   case NullabilityKind::Nullable:
 825     return OS << "Nullable";
 826   case NullabilityKind::NullableResult:
 827     return OS << "NullableResult";
 828   case NullabilityKind::Unspecified:
 829     return OS << "Unspecified";
 830   }
 831   llvm_unreachable("Unknown nullability kind.");
 832 }
 833
 834 diag::kind
 835 IdentifierTable::getFutureCompatDiagKind(const IdentifierInfo &II,
 836                                          const LangOptions &LangOpts) {
 837   assert(II.isFutureCompatKeyword() && "diagnostic should not be needed");
 838
 839   unsigned Flags = llvm::StringSwitch<unsigned>(II.getName())
 840 #define KEYWORD(NAME, FLAGS) .Case(#NAME, FLAGS)
 841 #include "clang/Basic/TokenKinds.def"
 842 #undef KEYWORD
 843       ;
 844
 845   if (LangOpts.CPlusPlus) {
 846     if ((Flags & KEYCXX11) == KEYCXX11)
 847       return diag::warn_cxx11_keyword;
 848
 849     // char8_t is not modeled as a CXX20_KEYWORD because it's not
 850     // unconditionally enabled in C++20 mode. (It can be disabled
 851     // by -fno-char8_t.)
 852     if (((Flags & KEYCXX20) == KEYCXX20) ||
 853         ((Flags & CHAR8SUPPORT) == CHAR8SUPPORT))
 854       return diag::warn_cxx20_keyword;
 855   } else {
 856     if ((Flags & KEYC99) == KEYC99)
 857       return diag::warn_c99_keyword;
 858     if ((Flags & KEYC23) == KEYC23)
 859       return diag::warn_c23_keyword;
 860   }
 861
 862   llvm_unreachable(
 863       "Keyword not known to come from a newer Standard or proposed Standard");
 864 }