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/IdentifierTable.h"
16 #include "clang/Basic/CharInfo.h"
17 #include "clang/Basic/LangOptions.h"
18 #include "clang/Basic/OperatorKinds.h"
19 #include "clang/Basic/Specifiers.h"
20 #include "clang/Basic/TokenKinds.h"
21 #include "llvm/ADT/DenseMapInfo.h"
22 #include "llvm/ADT/FoldingSet.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/Support/Allocator.h"
27 #include "llvm/Support/ErrorHandling.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 //===----------------------------------------------------------------------===//
37 // IdentifierInfo Implementation
38 //===----------------------------------------------------------------------===//
39 
40 IdentifierInfo::IdentifierInfo() {
41   TokenID = tok::identifier;
42   ObjCOrBuiltinID = 0;
43   HasMacro = false;
44   HadMacro = false;
45   IsExtension = false;
46   IsFutureCompatKeyword = false;
47   IsPoisoned = false;
48   IsCPPOperatorKeyword = false;
49   NeedsHandleIdentifier = false;
50   IsFromAST = false;
51   ChangedAfterLoad = false;
52   FEChangedAfterLoad = false;
53   RevertedTokenID = false;
54   OutOfDate = false;
55   IsModulesImport = false;
56 }
57 
58 //===----------------------------------------------------------------------===//
59 // IdentifierTable Implementation
60 //===----------------------------------------------------------------------===//
61 
62 IdentifierIterator::~IdentifierIterator() = default;
63 
64 IdentifierInfoLookup::~IdentifierInfoLookup() = default;
65 
66 namespace {
67 
68 /// \brief A simple identifier lookup iterator that represents an
69 /// empty sequence of identifiers.
70 class EmptyLookupIterator : public IdentifierIterator
71 {
72 public:
73   StringRef Next() override { return StringRef(); }
74 };
75 
76 } // namespace
77 
78 IdentifierIterator *IdentifierInfoLookup::getIdentifiers() {
79   return new EmptyLookupIterator();
80 }
81 
82 IdentifierTable::IdentifierTable(IdentifierInfoLookup *ExternalLookup)
83     : HashTable(8192), // Start with space for 8K identifiers.
84       ExternalLookup(ExternalLookup) {}
85 
86 IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
87                                  IdentifierInfoLookup *ExternalLookup)
88     : IdentifierTable(ExternalLookup) {
89   // Populate the identifier table with info about keywords for the current
90   // language.
91   AddKeywords(LangOpts);
92 }
93 
94 //===----------------------------------------------------------------------===//
95 // Language Keyword Implementation
96 //===----------------------------------------------------------------------===//
97 
98 // Constants for TokenKinds.def
99 namespace {
100 
101   enum {
102     KEYC99 = 0x1,
103     KEYCXX = 0x2,
104     KEYCXX11 = 0x4,
105     KEYGNU = 0x8,
106     KEYMS = 0x10,
107     BOOLSUPPORT = 0x20,
108     KEYALTIVEC = 0x40,
109     KEYNOCXX = 0x80,
110     KEYBORLAND = 0x100,
111     KEYOPENCL = 0x200,
112     KEYC11 = 0x400,
113     KEYARC = 0x800,
114     KEYNOMS18 = 0x01000,
115     KEYNOOPENCL = 0x02000,
116     WCHARSUPPORT = 0x04000,
117     HALFSUPPORT = 0x08000,
118     CHAR8SUPPORT = 0x10000,
119     KEYCONCEPTS = 0x20000,
120     KEYOBJC2    = 0x40000,
121     KEYZVECTOR  = 0x80000,
122     KEYCOROUTINES = 0x100000,
123     KEYMODULES = 0x200000,
124     KEYCXX2A = 0x400000,
125     KEYALLCXX = KEYCXX | KEYCXX11 | KEYCXX2A,
126     KEYALL = (0x7fffff & ~KEYNOMS18 &
127               ~KEYNOOPENCL) // KEYNOMS18 and KEYNOOPENCL are used to exclude.
128   };
129 
130   /// \brief How a keyword is treated in the selected standard.
131   enum KeywordStatus {
132     KS_Disabled,    // Disabled
133     KS_Extension,   // Is an extension
134     KS_Enabled,     // Enabled
135     KS_Future       // Is a keyword in future standard
136   };
137 
138 } // namespace
139 
140 /// \brief Translates flags as specified in TokenKinds.def into keyword status
141 /// in the given language standard.
142 static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
143                                       unsigned Flags) {
144   if (Flags == KEYALL) return KS_Enabled;
145   if (LangOpts.CPlusPlus && (Flags & KEYCXX)) return KS_Enabled;
146   if (LangOpts.CPlusPlus11 && (Flags & KEYCXX11)) return KS_Enabled;
147   if (LangOpts.CPlusPlus2a && (Flags & KEYCXX2A)) return KS_Enabled;
148   if (LangOpts.C99 && (Flags & KEYC99)) return KS_Enabled;
149   if (LangOpts.GNUKeywords && (Flags & KEYGNU)) return KS_Extension;
150   if (LangOpts.MicrosoftExt && (Flags & KEYMS)) return KS_Extension;
151   if (LangOpts.Borland && (Flags & KEYBORLAND)) return KS_Extension;
152   if (LangOpts.Bool && (Flags & BOOLSUPPORT)) return KS_Enabled;
153   if (LangOpts.Half && (Flags & HALFSUPPORT)) return KS_Enabled;
154   if (LangOpts.WChar && (Flags & WCHARSUPPORT)) return KS_Enabled;
155   if (LangOpts.Char8 && (Flags & CHAR8SUPPORT)) return KS_Enabled;
156   if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) return KS_Enabled;
157   if (LangOpts.OpenCL && (Flags & KEYOPENCL)) return KS_Enabled;
158   if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) return KS_Enabled;
159   if (LangOpts.C11 && (Flags & KEYC11)) return KS_Enabled;
160   // We treat bridge casts as objective-C keywords so we can warn on them
161   // in non-arc mode.
162   if (LangOpts.ObjC2 && (Flags & KEYARC)) return KS_Enabled;
163   if (LangOpts.ObjC2 && (Flags & KEYOBJC2)) return KS_Enabled;
164   if (LangOpts.ConceptsTS && (Flags & KEYCONCEPTS)) return KS_Enabled;
165   if (LangOpts.CoroutinesTS && (Flags & KEYCOROUTINES)) return KS_Enabled;
166   if (LangOpts.ModulesTS && (Flags & KEYMODULES)) return KS_Enabled;
167   if (LangOpts.CPlusPlus && (Flags & KEYALLCXX)) return KS_Future;
168   return KS_Disabled;
169 }
170 
171 /// AddKeyword - This method is used to associate a token ID with specific
172 /// identifiers because they are language keywords.  This causes the lexer to
173 /// automatically map matching identifiers to specialized token codes.
174 static void AddKeyword(StringRef Keyword,
175                        tok::TokenKind TokenCode, unsigned Flags,
176                        const LangOptions &LangOpts, IdentifierTable &Table) {
177   KeywordStatus AddResult = getKeywordStatus(LangOpts, Flags);
178 
179   // Don't add this keyword under MSVCCompat.
180   if (LangOpts.MSVCCompat && (Flags & KEYNOMS18) &&
181       !LangOpts.isCompatibleWithMSVC(LangOptions::MSVC2015))
182     return;
183 
184   // Don't add this keyword under OpenCL.
185   if (LangOpts.OpenCL && (Flags & KEYNOOPENCL))
186     return;
187 
188   // Don't add this keyword if disabled in this language.
189   if (AddResult == KS_Disabled) return;
190 
191   IdentifierInfo &Info =
192       Table.get(Keyword, AddResult == KS_Future ? tok::identifier : TokenCode);
193   Info.setIsExtensionToken(AddResult == KS_Extension);
194   Info.setIsFutureCompatKeyword(AddResult == KS_Future);
195 }
196 
197 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
198 /// representations.
199 static void AddCXXOperatorKeyword(StringRef Keyword,
200                                   tok::TokenKind TokenCode,
201                                   IdentifierTable &Table) {
202   IdentifierInfo &Info = Table.get(Keyword, TokenCode);
203   Info.setIsCPlusPlusOperatorKeyword();
204 }
205 
206 /// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
207 /// or "property".
208 static void AddObjCKeyword(StringRef Name,
209                            tok::ObjCKeywordKind ObjCID,
210                            IdentifierTable &Table) {
211   Table.get(Name).setObjCKeywordID(ObjCID);
212 }
213 
214 /// AddKeywords - Add all keywords to the symbol table.
215 ///
216 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
217   // Add keywords and tokens for the current language.
218 #define KEYWORD(NAME, FLAGS) \
219   AddKeyword(StringRef(#NAME), tok::kw_ ## NAME,  \
220              FLAGS, LangOpts, *this);
221 #define ALIAS(NAME, TOK, FLAGS) \
222   AddKeyword(StringRef(NAME), tok::kw_ ## TOK,  \
223              FLAGS, LangOpts, *this);
224 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
225   if (LangOpts.CXXOperatorNames)          \
226     AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
227 #define OBJC1_AT_KEYWORD(NAME) \
228   if (LangOpts.ObjC1)          \
229     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
230 #define OBJC2_AT_KEYWORD(NAME) \
231   if (LangOpts.ObjC2)          \
232     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
233 #define TESTING_KEYWORD(NAME, FLAGS)
234 #include "clang/Basic/TokenKinds.def"
235 
236   if (LangOpts.ParseUnknownAnytype)
237     AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
238                LangOpts, *this);
239 
240   if (LangOpts.DeclSpecKeyword)
241     AddKeyword("__declspec", tok::kw___declspec, KEYALL, LangOpts, *this);
242 
243   // Add the '_experimental_modules_import' contextual keyword.
244   get("import").setModulesImport(true);
245 }
246 
247 /// \brief Checks if the specified token kind represents a keyword in the
248 /// specified language.
249 /// \returns Status of the keyword in the language.
250 static KeywordStatus getTokenKwStatus(const LangOptions &LangOpts,
251                                       tok::TokenKind K) {
252   switch (K) {
253 #define KEYWORD(NAME, FLAGS) \
254   case tok::kw_##NAME: return getKeywordStatus(LangOpts, FLAGS);
255 #include "clang/Basic/TokenKinds.def"
256   default: return KS_Disabled;
257   }
258 }
259 
260 /// \brief Returns true if the identifier represents a keyword in the
261 /// specified language.
262 bool IdentifierInfo::isKeyword(const LangOptions &LangOpts) const {
263   switch (getTokenKwStatus(LangOpts, getTokenID())) {
264   case KS_Enabled:
265   case KS_Extension:
266     return true;
267   default:
268     return false;
269   }
270 }
271 
272 /// \brief Returns true if the identifier represents a C++ keyword in the
273 /// specified language.
274 bool IdentifierInfo::isCPlusPlusKeyword(const LangOptions &LangOpts) const {
275   if (!LangOpts.CPlusPlus || !isKeyword(LangOpts))
276     return false;
277   // This is a C++ keyword if this identifier is not a keyword when checked
278   // using LangOptions without C++ support.
279   LangOptions LangOptsNoCPP = LangOpts;
280   LangOptsNoCPP.CPlusPlus = false;
281   LangOptsNoCPP.CPlusPlus11 = false;
282   LangOptsNoCPP.CPlusPlus2a = false;
283   return !isKeyword(LangOptsNoCPP);
284 }
285 
286 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
287   // We use a perfect hash function here involving the length of the keyword,
288   // the first and third character.  For preprocessor ID's there are no
289   // collisions (if there were, the switch below would complain about duplicate
290   // case values).  Note that this depends on 'if' being null terminated.
291 
292 #define HASH(LEN, FIRST, THIRD) \
293   (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
294 #define CASE(LEN, FIRST, THIRD, NAME) \
295   case HASH(LEN, FIRST, THIRD): \
296     return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
297 
298   unsigned Len = getLength();
299   if (Len < 2) return tok::pp_not_keyword;
300   const char *Name = getNameStart();
301   switch (HASH(Len, Name[0], Name[2])) {
302   default: return tok::pp_not_keyword;
303   CASE( 2, 'i', '\0', if);
304   CASE( 4, 'e', 'i', elif);
305   CASE( 4, 'e', 's', else);
306   CASE( 4, 'l', 'n', line);
307   CASE( 4, 's', 'c', sccs);
308   CASE( 5, 'e', 'd', endif);
309   CASE( 5, 'e', 'r', error);
310   CASE( 5, 'i', 'e', ident);
311   CASE( 5, 'i', 'd', ifdef);
312   CASE( 5, 'u', 'd', undef);
313 
314   CASE( 6, 'a', 's', assert);
315   CASE( 6, 'd', 'f', define);
316   CASE( 6, 'i', 'n', ifndef);
317   CASE( 6, 'i', 'p', import);
318   CASE( 6, 'p', 'a', pragma);
319 
320   CASE( 7, 'd', 'f', defined);
321   CASE( 7, 'i', 'c', include);
322   CASE( 7, 'w', 'r', warning);
323 
324   CASE( 8, 'u', 'a', unassert);
325   CASE(12, 'i', 'c', include_next);
326 
327   CASE(14, '_', 'p', __public_macro);
328 
329   CASE(15, '_', 'p', __private_macro);
330 
331   CASE(16, '_', 'i', __include_macros);
332 #undef CASE
333 #undef HASH
334   }
335 }
336 
337 //===----------------------------------------------------------------------===//
338 // Stats Implementation
339 //===----------------------------------------------------------------------===//
340 
341 /// PrintStats - Print statistics about how well the identifier table is doing
342 /// at hashing identifiers.
343 void IdentifierTable::PrintStats() const {
344   unsigned NumBuckets = HashTable.getNumBuckets();
345   unsigned NumIdentifiers = HashTable.getNumItems();
346   unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
347   unsigned AverageIdentifierSize = 0;
348   unsigned MaxIdentifierLength = 0;
349 
350   // TODO: Figure out maximum times an identifier had to probe for -stats.
351   for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
352        I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
353     unsigned IdLen = I->getKeyLength();
354     AverageIdentifierSize += IdLen;
355     if (MaxIdentifierLength < IdLen)
356       MaxIdentifierLength = IdLen;
357   }
358 
359   fprintf(stderr, "\n*** Identifier Table Stats:\n");
360   fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
361   fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
362   fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
363           NumIdentifiers/(double)NumBuckets);
364   fprintf(stderr, "Ave identifier length: %f\n",
365           (AverageIdentifierSize/(double)NumIdentifiers));
366   fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
367 
368   // Compute statistics about the memory allocated for identifiers.
369   HashTable.getAllocator().PrintStats();
370 }
371 
372 //===----------------------------------------------------------------------===//
373 // SelectorTable Implementation
374 //===----------------------------------------------------------------------===//
375 
376 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
377   return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
378 }
379 
380 namespace clang {
381 
382 /// MultiKeywordSelector - One of these variable length records is kept for each
383 /// selector containing more than one keyword. We use a folding set
384 /// to unique aggregate names (keyword selectors in ObjC parlance). Access to
385 /// this class is provided strictly through Selector.
386 class MultiKeywordSelector
387   : public DeclarationNameExtra, public llvm::FoldingSetNode {
388   MultiKeywordSelector(unsigned nKeys) {
389     ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
390   }
391 
392 public:
393   // Constructor for keyword selectors.
394   MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV) {
395     assert((nKeys > 1) && "not a multi-keyword selector");
396     ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
397 
398     // Fill in the trailing keyword array.
399     IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1);
400     for (unsigned i = 0; i != nKeys; ++i)
401       KeyInfo[i] = IIV[i];
402   }
403 
404   // getName - Derive the full selector name and return it.
405   std::string getName() const;
406 
407   unsigned getNumArgs() const { return ExtraKindOrNumArgs - NUM_EXTRA_KINDS; }
408 
409   using keyword_iterator = IdentifierInfo *const *;
410 
411   keyword_iterator keyword_begin() const {
412     return reinterpret_cast<keyword_iterator>(this+1);
413   }
414 
415   keyword_iterator keyword_end() const {
416     return keyword_begin()+getNumArgs();
417   }
418 
419   IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
420     assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
421     return keyword_begin()[i];
422   }
423 
424   static void Profile(llvm::FoldingSetNodeID &ID,
425                       keyword_iterator ArgTys, unsigned NumArgs) {
426     ID.AddInteger(NumArgs);
427     for (unsigned i = 0; i != NumArgs; ++i)
428       ID.AddPointer(ArgTys[i]);
429   }
430 
431   void Profile(llvm::FoldingSetNodeID &ID) {
432     Profile(ID, keyword_begin(), getNumArgs());
433   }
434 };
435 
436 } // namespace clang.
437 
438 unsigned Selector::getNumArgs() const {
439   unsigned IIF = getIdentifierInfoFlag();
440   if (IIF <= ZeroArg)
441     return 0;
442   if (IIF == OneArg)
443     return 1;
444   // We point to a MultiKeywordSelector.
445   MultiKeywordSelector *SI = getMultiKeywordSelector();
446   return SI->getNumArgs();
447 }
448 
449 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
450   if (getIdentifierInfoFlag() < MultiArg) {
451     assert(argIndex == 0 && "illegal keyword index");
452     return getAsIdentifierInfo();
453   }
454 
455   // We point to a MultiKeywordSelector.
456   MultiKeywordSelector *SI = getMultiKeywordSelector();
457   return SI->getIdentifierInfoForSlot(argIndex);
458 }
459 
460 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
461   IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
462   return II? II->getName() : StringRef();
463 }
464 
465 std::string MultiKeywordSelector::getName() const {
466   SmallString<256> Str;
467   llvm::raw_svector_ostream OS(Str);
468   for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
469     if (*I)
470       OS << (*I)->getName();
471     OS << ':';
472   }
473 
474   return OS.str();
475 }
476 
477 std::string Selector::getAsString() const {
478   if (InfoPtr == 0)
479     return "<null selector>";
480 
481   if (getIdentifierInfoFlag() < MultiArg) {
482     IdentifierInfo *II = getAsIdentifierInfo();
483 
484     if (getNumArgs() == 0) {
485       assert(II && "If the number of arguments is 0 then II is guaranteed to "
486                    "not be null.");
487       return II->getName();
488     }
489 
490     if (!II)
491       return ":";
492 
493     return II->getName().str() + ":";
494   }
495 
496   // We have a multiple keyword selector.
497   return getMultiKeywordSelector()->getName();
498 }
499 
500 void Selector::print(llvm::raw_ostream &OS) const {
501   OS << getAsString();
502 }
503 
504 /// Interpreting the given string using the normal CamelCase
505 /// conventions, determine whether the given string starts with the
506 /// given "word", which is assumed to end in a lowercase letter.
507 static bool startsWithWord(StringRef name, StringRef word) {
508   if (name.size() < word.size()) return false;
509   return ((name.size() == word.size() || !isLowercase(name[word.size()])) &&
510           name.startswith(word));
511 }
512 
513 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
514   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
515   if (!first) return OMF_None;
516 
517   StringRef name = first->getName();
518   if (sel.isUnarySelector()) {
519     if (name == "autorelease") return OMF_autorelease;
520     if (name == "dealloc") return OMF_dealloc;
521     if (name == "finalize") return OMF_finalize;
522     if (name == "release") return OMF_release;
523     if (name == "retain") return OMF_retain;
524     if (name == "retainCount") return OMF_retainCount;
525     if (name == "self") return OMF_self;
526     if (name == "initialize") return OMF_initialize;
527   }
528 
529   if (name == "performSelector" || name == "performSelectorInBackground" ||
530       name == "performSelectorOnMainThread")
531     return OMF_performSelector;
532 
533   // The other method families may begin with a prefix of underscores.
534   while (!name.empty() && name.front() == '_')
535     name = name.substr(1);
536 
537   if (name.empty()) return OMF_None;
538   switch (name.front()) {
539   case 'a':
540     if (startsWithWord(name, "alloc")) return OMF_alloc;
541     break;
542   case 'c':
543     if (startsWithWord(name, "copy")) return OMF_copy;
544     break;
545   case 'i':
546     if (startsWithWord(name, "init")) return OMF_init;
547     break;
548   case 'm':
549     if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
550     break;
551   case 'n':
552     if (startsWithWord(name, "new")) return OMF_new;
553     break;
554   default:
555     break;
556   }
557 
558   return OMF_None;
559 }
560 
561 ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
562   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
563   if (!first) return OIT_None;
564 
565   StringRef name = first->getName();
566 
567   if (name.empty()) return OIT_None;
568   switch (name.front()) {
569     case 'a':
570       if (startsWithWord(name, "array")) return OIT_Array;
571       break;
572     case 'd':
573       if (startsWithWord(name, "default")) return OIT_ReturnsSelf;
574       if (startsWithWord(name, "dictionary")) return OIT_Dictionary;
575       break;
576     case 's':
577       if (startsWithWord(name, "shared")) return OIT_ReturnsSelf;
578       if (startsWithWord(name, "standard")) return OIT_Singleton;
579       break;
580     case 'i':
581       if (startsWithWord(name, "init")) return OIT_Init;
582     default:
583       break;
584   }
585   return OIT_None;
586 }
587 
588 ObjCStringFormatFamily Selector::getStringFormatFamilyImpl(Selector sel) {
589   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
590   if (!first) return SFF_None;
591 
592   StringRef name = first->getName();
593 
594   switch (name.front()) {
595     case 'a':
596       if (name == "appendFormat") return SFF_NSString;
597       break;
598 
599     case 'i':
600       if (name == "initWithFormat") return SFF_NSString;
601       break;
602 
603     case 'l':
604       if (name == "localizedStringWithFormat") return SFF_NSString;
605       break;
606 
607     case 's':
608       if (name == "stringByAppendingFormat" ||
609           name == "stringWithFormat") return SFF_NSString;
610       break;
611   }
612   return SFF_None;
613 }
614 
615 namespace {
616 
617 struct SelectorTableImpl {
618   llvm::FoldingSet<MultiKeywordSelector> Table;
619   llvm::BumpPtrAllocator Allocator;
620 };
621 
622 } // namespace
623 
624 static SelectorTableImpl &getSelectorTableImpl(void *P) {
625   return *static_cast<SelectorTableImpl*>(P);
626 }
627 
628 SmallString<64>
629 SelectorTable::constructSetterName(StringRef Name) {
630   SmallString<64> SetterName("set");
631   SetterName += Name;
632   SetterName[3] = toUppercase(SetterName[3]);
633   return SetterName;
634 }
635 
636 Selector
637 SelectorTable::constructSetterSelector(IdentifierTable &Idents,
638                                        SelectorTable &SelTable,
639                                        const IdentifierInfo *Name) {
640   IdentifierInfo *SetterName =
641     &Idents.get(constructSetterName(Name->getName()));
642   return SelTable.getUnarySelector(SetterName);
643 }
644 
645 size_t SelectorTable::getTotalMemory() const {
646   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
647   return SelTabImpl.Allocator.getTotalMemory();
648 }
649 
650 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
651   if (nKeys < 2)
652     return Selector(IIV[0], nKeys);
653 
654   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
655 
656   // Unique selector, to guarantee there is one per name.
657   llvm::FoldingSetNodeID ID;
658   MultiKeywordSelector::Profile(ID, IIV, nKeys);
659 
660   void *InsertPos = nullptr;
661   if (MultiKeywordSelector *SI =
662         SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
663     return Selector(SI);
664 
665   // MultiKeywordSelector objects are not allocated with new because they have a
666   // variable size array (for parameter types) at the end of them.
667   unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
668   MultiKeywordSelector *SI =
669       (MultiKeywordSelector *)SelTabImpl.Allocator.Allocate(
670           Size, alignof(MultiKeywordSelector));
671   new (SI) MultiKeywordSelector(nKeys, IIV);
672   SelTabImpl.Table.InsertNode(SI, InsertPos);
673   return Selector(SI);
674 }
675 
676 SelectorTable::SelectorTable() {
677   Impl = new SelectorTableImpl();
678 }
679 
680 SelectorTable::~SelectorTable() {
681   delete &getSelectorTableImpl(Impl);
682 }
683 
684 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
685   switch (Operator) {
686   case OO_None:
687   case NUM_OVERLOADED_OPERATORS:
688     return nullptr;
689 
690 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
691   case OO_##Name: return Spelling;
692 #include "clang/Basic/OperatorKinds.def"
693   }
694 
695   llvm_unreachable("Invalid OverloadedOperatorKind!");
696 }
697 
698 StringRef clang::getNullabilitySpelling(NullabilityKind kind,
699                                         bool isContextSensitive) {
700   switch (kind) {
701   case NullabilityKind::NonNull:
702     return isContextSensitive ? "nonnull" : "_Nonnull";
703 
704   case NullabilityKind::Nullable:
705     return isContextSensitive ? "nullable" : "_Nullable";
706 
707   case NullabilityKind::Unspecified:
708     return isContextSensitive ? "null_unspecified" : "_Null_unspecified";
709   }
710   llvm_unreachable("Unknown nullability kind.");
711 }
712