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