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     KEYCONCEPTS = 0x10000,
113     KEYALL = (0x1ffff & ~KEYNOMS18 &
114               ~KEYNOOPENCL) // KEYNOMS18 and KEYNOOPENCL are used to exclude.
115   };
116 
117   /// \brief How a keyword is treated in the selected standard.
118   enum KeywordStatus {
119     KS_Disabled,    // Disabled
120     KS_Extension,   // Is an extension
121     KS_Enabled,     // Enabled
122     KS_Future       // Is a keyword in future standard
123   };
124 }
125 
126 /// \brief Translates flags as specified in TokenKinds.def into keyword status
127 /// in the given language standard.
128 static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
129                                       unsigned Flags) {
130   if (Flags == KEYALL) return KS_Enabled;
131   if (LangOpts.CPlusPlus && (Flags & KEYCXX)) return KS_Enabled;
132   if (LangOpts.CPlusPlus11 && (Flags & KEYCXX11)) return KS_Enabled;
133   if (LangOpts.C99 && (Flags & KEYC99)) return KS_Enabled;
134   if (LangOpts.GNUKeywords && (Flags & KEYGNU)) return KS_Extension;
135   if (LangOpts.MicrosoftExt && (Flags & KEYMS)) return KS_Extension;
136   if (LangOpts.Borland && (Flags & KEYBORLAND)) return KS_Extension;
137   if (LangOpts.Bool && (Flags & BOOLSUPPORT)) return KS_Enabled;
138   if (LangOpts.Half && (Flags & HALFSUPPORT)) return KS_Enabled;
139   if (LangOpts.WChar && (Flags & WCHARSUPPORT)) return KS_Enabled;
140   if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) return KS_Enabled;
141   if (LangOpts.OpenCL && (Flags & KEYOPENCL)) return KS_Enabled;
142   if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) return KS_Enabled;
143   if (LangOpts.C11 && (Flags & KEYC11)) return KS_Enabled;
144   // We treat bridge casts as objective-C keywords so we can warn on them
145   // in non-arc mode.
146   if (LangOpts.ObjC2 && (Flags & KEYARC)) return KS_Enabled;
147   if (LangOpts.ConceptsTS && (Flags & KEYCONCEPTS)) return KS_Enabled;
148   if (LangOpts.CPlusPlus && (Flags & KEYCXX11)) return KS_Future;
149   return KS_Disabled;
150 }
151 
152 /// AddKeyword - This method is used to associate a token ID with specific
153 /// identifiers because they are language keywords.  This causes the lexer to
154 /// automatically map matching identifiers to specialized token codes.
155 static void AddKeyword(StringRef Keyword,
156                        tok::TokenKind TokenCode, unsigned Flags,
157                        const LangOptions &LangOpts, IdentifierTable &Table) {
158   KeywordStatus AddResult = getKeywordStatus(LangOpts, Flags);
159 
160   // Don't add this keyword under MSVCCompat.
161   if (LangOpts.MSVCCompat && (Flags & KEYNOMS18) &&
162       !LangOpts.isCompatibleWithMSVC(LangOptions::MSVC2015))
163     return;
164 
165   // Don't add this keyword under OpenCL.
166   if (LangOpts.OpenCL && (Flags & KEYNOOPENCL))
167     return;
168 
169   // Don't add this keyword if disabled in this language.
170   if (AddResult == KS_Disabled) return;
171 
172   IdentifierInfo &Info =
173       Table.get(Keyword, AddResult == KS_Future ? tok::identifier : TokenCode);
174   Info.setIsExtensionToken(AddResult == KS_Extension);
175   Info.setIsFutureCompatKeyword(AddResult == KS_Future);
176 }
177 
178 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
179 /// representations.
180 static void AddCXXOperatorKeyword(StringRef Keyword,
181                                   tok::TokenKind TokenCode,
182                                   IdentifierTable &Table) {
183   IdentifierInfo &Info = Table.get(Keyword, TokenCode);
184   Info.setIsCPlusPlusOperatorKeyword();
185 }
186 
187 /// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
188 /// or "property".
189 static void AddObjCKeyword(StringRef Name,
190                            tok::ObjCKeywordKind ObjCID,
191                            IdentifierTable &Table) {
192   Table.get(Name).setObjCKeywordID(ObjCID);
193 }
194 
195 /// AddKeywords - Add all keywords to the symbol table.
196 ///
197 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
198   // Add keywords and tokens for the current language.
199 #define KEYWORD(NAME, FLAGS) \
200   AddKeyword(StringRef(#NAME), tok::kw_ ## NAME,  \
201              FLAGS, LangOpts, *this);
202 #define ALIAS(NAME, TOK, FLAGS) \
203   AddKeyword(StringRef(NAME), tok::kw_ ## TOK,  \
204              FLAGS, LangOpts, *this);
205 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
206   if (LangOpts.CXXOperatorNames)          \
207     AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
208 #define OBJC1_AT_KEYWORD(NAME) \
209   if (LangOpts.ObjC1)          \
210     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
211 #define OBJC2_AT_KEYWORD(NAME) \
212   if (LangOpts.ObjC2)          \
213     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
214 #define TESTING_KEYWORD(NAME, FLAGS)
215 #include "clang/Basic/TokenKinds.def"
216 
217   if (LangOpts.ParseUnknownAnytype)
218     AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
219                LangOpts, *this);
220 
221   // FIXME: __declspec isn't really a CUDA extension, however it is required for
222   // supporting cuda_builtin_vars.h, which uses __declspec(property). Once that
223   // has been rewritten in terms of something more generic, remove this code.
224   if (LangOpts.CUDA)
225     AddKeyword("__declspec", tok::kw___declspec, KEYALL, LangOpts, *this);
226 }
227 
228 /// \brief Checks if the specified token kind represents a keyword in the
229 /// specified language.
230 /// \returns Status of the keyword in the language.
231 static KeywordStatus getTokenKwStatus(const LangOptions &LangOpts,
232                                       tok::TokenKind K) {
233   switch (K) {
234 #define KEYWORD(NAME, FLAGS) \
235   case tok::kw_##NAME: return getKeywordStatus(LangOpts, FLAGS);
236 #include "clang/Basic/TokenKinds.def"
237   default: return KS_Disabled;
238   }
239 }
240 
241 /// \brief Returns true if the identifier represents a keyword in the
242 /// specified language.
243 bool IdentifierInfo::isKeyword(const LangOptions &LangOpts) {
244   switch (getTokenKwStatus(LangOpts, getTokenID())) {
245   case KS_Enabled:
246   case KS_Extension:
247     return true;
248   default:
249     return false;
250   }
251 }
252 
253 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
254   // We use a perfect hash function here involving the length of the keyword,
255   // the first and third character.  For preprocessor ID's there are no
256   // collisions (if there were, the switch below would complain about duplicate
257   // case values).  Note that this depends on 'if' being null terminated.
258 
259 #define HASH(LEN, FIRST, THIRD) \
260   (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
261 #define CASE(LEN, FIRST, THIRD, NAME) \
262   case HASH(LEN, FIRST, THIRD): \
263     return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
264 
265   unsigned Len = getLength();
266   if (Len < 2) return tok::pp_not_keyword;
267   const char *Name = getNameStart();
268   switch (HASH(Len, Name[0], Name[2])) {
269   default: return tok::pp_not_keyword;
270   CASE( 2, 'i', '\0', if);
271   CASE( 4, 'e', 'i', elif);
272   CASE( 4, 'e', 's', else);
273   CASE( 4, 'l', 'n', line);
274   CASE( 4, 's', 'c', sccs);
275   CASE( 5, 'e', 'd', endif);
276   CASE( 5, 'e', 'r', error);
277   CASE( 5, 'i', 'e', ident);
278   CASE( 5, 'i', 'd', ifdef);
279   CASE( 5, 'u', 'd', undef);
280 
281   CASE( 6, 'a', 's', assert);
282   CASE( 6, 'd', 'f', define);
283   CASE( 6, 'i', 'n', ifndef);
284   CASE( 6, 'i', 'p', import);
285   CASE( 6, 'p', 'a', pragma);
286 
287   CASE( 7, 'd', 'f', defined);
288   CASE( 7, 'i', 'c', include);
289   CASE( 7, 'w', 'r', warning);
290 
291   CASE( 8, 'u', 'a', unassert);
292   CASE(12, 'i', 'c', include_next);
293 
294   CASE(14, '_', 'p', __public_macro);
295 
296   CASE(15, '_', 'p', __private_macro);
297 
298   CASE(16, '_', 'i', __include_macros);
299 #undef CASE
300 #undef HASH
301   }
302 }
303 
304 //===----------------------------------------------------------------------===//
305 // Stats Implementation
306 //===----------------------------------------------------------------------===//
307 
308 /// PrintStats - Print statistics about how well the identifier table is doing
309 /// at hashing identifiers.
310 void IdentifierTable::PrintStats() const {
311   unsigned NumBuckets = HashTable.getNumBuckets();
312   unsigned NumIdentifiers = HashTable.getNumItems();
313   unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
314   unsigned AverageIdentifierSize = 0;
315   unsigned MaxIdentifierLength = 0;
316 
317   // TODO: Figure out maximum times an identifier had to probe for -stats.
318   for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
319        I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
320     unsigned IdLen = I->getKeyLength();
321     AverageIdentifierSize += IdLen;
322     if (MaxIdentifierLength < IdLen)
323       MaxIdentifierLength = IdLen;
324   }
325 
326   fprintf(stderr, "\n*** Identifier Table Stats:\n");
327   fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
328   fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
329   fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
330           NumIdentifiers/(double)NumBuckets);
331   fprintf(stderr, "Ave identifier length: %f\n",
332           (AverageIdentifierSize/(double)NumIdentifiers));
333   fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
334 
335   // Compute statistics about the memory allocated for identifiers.
336   HashTable.getAllocator().PrintStats();
337 }
338 
339 //===----------------------------------------------------------------------===//
340 // SelectorTable Implementation
341 //===----------------------------------------------------------------------===//
342 
343 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
344   return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
345 }
346 
347 namespace clang {
348 /// MultiKeywordSelector - One of these variable length records is kept for each
349 /// selector containing more than one keyword. We use a folding set
350 /// to unique aggregate names (keyword selectors in ObjC parlance). Access to
351 /// this class is provided strictly through Selector.
352 class MultiKeywordSelector
353   : public DeclarationNameExtra, public llvm::FoldingSetNode {
354   MultiKeywordSelector(unsigned nKeys) {
355     ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
356   }
357 public:
358   // Constructor for keyword selectors.
359   MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV) {
360     assert((nKeys > 1) && "not a multi-keyword selector");
361     ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
362 
363     // Fill in the trailing keyword array.
364     IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1);
365     for (unsigned i = 0; i != nKeys; ++i)
366       KeyInfo[i] = IIV[i];
367   }
368 
369   // getName - Derive the full selector name and return it.
370   std::string getName() const;
371 
372   unsigned getNumArgs() const { return ExtraKindOrNumArgs - NUM_EXTRA_KINDS; }
373 
374   typedef IdentifierInfo *const *keyword_iterator;
375   keyword_iterator keyword_begin() const {
376     return reinterpret_cast<keyword_iterator>(this+1);
377   }
378   keyword_iterator keyword_end() const {
379     return keyword_begin()+getNumArgs();
380   }
381   IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
382     assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
383     return keyword_begin()[i];
384   }
385   static void Profile(llvm::FoldingSetNodeID &ID,
386                       keyword_iterator ArgTys, unsigned NumArgs) {
387     ID.AddInteger(NumArgs);
388     for (unsigned i = 0; i != NumArgs; ++i)
389       ID.AddPointer(ArgTys[i]);
390   }
391   void Profile(llvm::FoldingSetNodeID &ID) {
392     Profile(ID, keyword_begin(), getNumArgs());
393   }
394 };
395 } // end namespace clang.
396 
397 unsigned Selector::getNumArgs() const {
398   unsigned IIF = getIdentifierInfoFlag();
399   if (IIF <= ZeroArg)
400     return 0;
401   if (IIF == OneArg)
402     return 1;
403   // We point to a MultiKeywordSelector.
404   MultiKeywordSelector *SI = getMultiKeywordSelector();
405   return SI->getNumArgs();
406 }
407 
408 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
409   if (getIdentifierInfoFlag() < MultiArg) {
410     assert(argIndex == 0 && "illegal keyword index");
411     return getAsIdentifierInfo();
412   }
413   // We point to a MultiKeywordSelector.
414   MultiKeywordSelector *SI = getMultiKeywordSelector();
415   return SI->getIdentifierInfoForSlot(argIndex);
416 }
417 
418 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
419   IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
420   return II? II->getName() : StringRef();
421 }
422 
423 std::string MultiKeywordSelector::getName() const {
424   SmallString<256> Str;
425   llvm::raw_svector_ostream OS(Str);
426   for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
427     if (*I)
428       OS << (*I)->getName();
429     OS << ':';
430   }
431 
432   return OS.str();
433 }
434 
435 std::string Selector::getAsString() const {
436   if (InfoPtr == 0)
437     return "<null selector>";
438 
439   if (getIdentifierInfoFlag() < MultiArg) {
440     IdentifierInfo *II = getAsIdentifierInfo();
441 
442     // If the number of arguments is 0 then II is guaranteed to not be null.
443     if (getNumArgs() == 0)
444       return II->getName();
445 
446     if (!II)
447       return ":";
448 
449     return II->getName().str() + ":";
450   }
451 
452   // We have a multiple keyword selector.
453   return getMultiKeywordSelector()->getName();
454 }
455 
456 void Selector::print(llvm::raw_ostream &OS) const {
457   OS << getAsString();
458 }
459 
460 /// Interpreting the given string using the normal CamelCase
461 /// conventions, determine whether the given string starts with the
462 /// given "word", which is assumed to end in a lowercase letter.
463 static bool startsWithWord(StringRef name, StringRef word) {
464   if (name.size() < word.size()) return false;
465   return ((name.size() == word.size() || !isLowercase(name[word.size()])) &&
466           name.startswith(word));
467 }
468 
469 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
470   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
471   if (!first) return OMF_None;
472 
473   StringRef name = first->getName();
474   if (sel.isUnarySelector()) {
475     if (name == "autorelease") return OMF_autorelease;
476     if (name == "dealloc") return OMF_dealloc;
477     if (name == "finalize") return OMF_finalize;
478     if (name == "release") return OMF_release;
479     if (name == "retain") return OMF_retain;
480     if (name == "retainCount") return OMF_retainCount;
481     if (name == "self") return OMF_self;
482     if (name == "initialize") return OMF_initialize;
483   }
484 
485   if (name == "performSelector") return OMF_performSelector;
486 
487   // The other method families may begin with a prefix of underscores.
488   while (!name.empty() && name.front() == '_')
489     name = name.substr(1);
490 
491   if (name.empty()) return OMF_None;
492   switch (name.front()) {
493   case 'a':
494     if (startsWithWord(name, "alloc")) return OMF_alloc;
495     break;
496   case 'c':
497     if (startsWithWord(name, "copy")) return OMF_copy;
498     break;
499   case 'i':
500     if (startsWithWord(name, "init")) return OMF_init;
501     break;
502   case 'm':
503     if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
504     break;
505   case 'n':
506     if (startsWithWord(name, "new")) return OMF_new;
507     break;
508   default:
509     break;
510   }
511 
512   return OMF_None;
513 }
514 
515 ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
516   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
517   if (!first) return OIT_None;
518 
519   StringRef name = first->getName();
520 
521   if (name.empty()) return OIT_None;
522   switch (name.front()) {
523     case 'a':
524       if (startsWithWord(name, "array")) return OIT_Array;
525       break;
526     case 'd':
527       if (startsWithWord(name, "default")) return OIT_ReturnsSelf;
528       if (startsWithWord(name, "dictionary")) return OIT_Dictionary;
529       break;
530     case 's':
531       if (startsWithWord(name, "shared")) return OIT_ReturnsSelf;
532       if (startsWithWord(name, "standard")) return OIT_Singleton;
533     case 'i':
534       if (startsWithWord(name, "init")) return OIT_Init;
535     default:
536       break;
537   }
538   return OIT_None;
539 }
540 
541 ObjCStringFormatFamily Selector::getStringFormatFamilyImpl(Selector sel) {
542   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
543   if (!first) return SFF_None;
544 
545   StringRef name = first->getName();
546 
547   switch (name.front()) {
548     case 'a':
549       if (name == "appendFormat") return SFF_NSString;
550       break;
551 
552     case 'i':
553       if (name == "initWithFormat") return SFF_NSString;
554       break;
555 
556     case 'l':
557       if (name == "localizedStringWithFormat") return SFF_NSString;
558       break;
559 
560     case 's':
561       if (name == "stringByAppendingFormat" ||
562           name == "stringWithFormat") return SFF_NSString;
563       break;
564   }
565   return SFF_None;
566 }
567 
568 namespace {
569   struct SelectorTableImpl {
570     llvm::FoldingSet<MultiKeywordSelector> Table;
571     llvm::BumpPtrAllocator Allocator;
572   };
573 } // end anonymous namespace.
574 
575 static SelectorTableImpl &getSelectorTableImpl(void *P) {
576   return *static_cast<SelectorTableImpl*>(P);
577 }
578 
579 SmallString<64>
580 SelectorTable::constructSetterName(StringRef Name) {
581   SmallString<64> SetterName("set");
582   SetterName += Name;
583   SetterName[3] = toUppercase(SetterName[3]);
584   return SetterName;
585 }
586 
587 Selector
588 SelectorTable::constructSetterSelector(IdentifierTable &Idents,
589                                        SelectorTable &SelTable,
590                                        const IdentifierInfo *Name) {
591   IdentifierInfo *SetterName =
592     &Idents.get(constructSetterName(Name->getName()));
593   return SelTable.getUnarySelector(SetterName);
594 }
595 
596 size_t SelectorTable::getTotalMemory() const {
597   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
598   return SelTabImpl.Allocator.getTotalMemory();
599 }
600 
601 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
602   if (nKeys < 2)
603     return Selector(IIV[0], nKeys);
604 
605   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
606 
607   // Unique selector, to guarantee there is one per name.
608   llvm::FoldingSetNodeID ID;
609   MultiKeywordSelector::Profile(ID, IIV, nKeys);
610 
611   void *InsertPos = nullptr;
612   if (MultiKeywordSelector *SI =
613         SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
614     return Selector(SI);
615 
616   // MultiKeywordSelector objects are not allocated with new because they have a
617   // variable size array (for parameter types) at the end of them.
618   unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
619   MultiKeywordSelector *SI =
620     (MultiKeywordSelector*)SelTabImpl.Allocator.Allocate(Size,
621                                          llvm::alignOf<MultiKeywordSelector>());
622   new (SI) MultiKeywordSelector(nKeys, IIV);
623   SelTabImpl.Table.InsertNode(SI, InsertPos);
624   return Selector(SI);
625 }
626 
627 SelectorTable::SelectorTable() {
628   Impl = new SelectorTableImpl();
629 }
630 
631 SelectorTable::~SelectorTable() {
632   delete &getSelectorTableImpl(Impl);
633 }
634 
635 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
636   switch (Operator) {
637   case OO_None:
638   case NUM_OVERLOADED_OPERATORS:
639     return nullptr;
640 
641 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
642   case OO_##Name: return Spelling;
643 #include "clang/Basic/OperatorKinds.def"
644   }
645 
646   llvm_unreachable("Invalid OverloadedOperatorKind!");
647 }
648