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 /// 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     KEYOPENCLC = 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     KEYOPENCLCXX = 0x800000,
126     KEYALLCXX = KEYCXX | KEYCXX11 | KEYCXX2A,
127     KEYALL = (0xffffff & ~KEYNOMS18 &
128               ~KEYNOOPENCL) // KEYNOMS18 and KEYNOOPENCL are used to exclude.
129   };
130 
131   /// How a keyword is treated in the selected standard.
132   enum KeywordStatus {
133     KS_Disabled,    // Disabled
134     KS_Extension,   // Is an extension
135     KS_Enabled,     // Enabled
136     KS_Future       // Is a keyword in future standard
137   };
138 
139 } // namespace
140 
141 /// Translates flags as specified in TokenKinds.def into keyword status
142 /// in the given language standard.
143 static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
144                                       unsigned Flags) {
145   if (Flags == KEYALL) return KS_Enabled;
146   if (LangOpts.CPlusPlus && (Flags & KEYCXX)) return KS_Enabled;
147   if (LangOpts.CPlusPlus11 && (Flags & KEYCXX11)) return KS_Enabled;
148   if (LangOpts.CPlusPlus2a && (Flags & KEYCXX2A)) return KS_Enabled;
149   if (LangOpts.C99 && (Flags & KEYC99)) return KS_Enabled;
150   if (LangOpts.GNUKeywords && (Flags & KEYGNU)) return KS_Extension;
151   if (LangOpts.MicrosoftExt && (Flags & KEYMS)) return KS_Extension;
152   if (LangOpts.Borland && (Flags & KEYBORLAND)) return KS_Extension;
153   if (LangOpts.Bool && (Flags & BOOLSUPPORT)) return KS_Enabled;
154   if (LangOpts.Half && (Flags & HALFSUPPORT)) return KS_Enabled;
155   if (LangOpts.WChar && (Flags & WCHARSUPPORT)) return KS_Enabled;
156   if (LangOpts.Char8 && (Flags & CHAR8SUPPORT)) return KS_Enabled;
157   if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) return KS_Enabled;
158   if (LangOpts.OpenCL && !LangOpts.OpenCLCPlusPlus && (Flags & KEYOPENCLC))
159     return KS_Enabled;
160   if (LangOpts.OpenCLCPlusPlus && (Flags & KEYOPENCLCXX)) return KS_Enabled;
161   if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) return KS_Enabled;
162   if (LangOpts.C11 && (Flags & KEYC11)) return KS_Enabled;
163   // We treat bridge casts as objective-C keywords so we can warn on them
164   // in non-arc mode.
165   if (LangOpts.ObjC2 && (Flags & KEYARC)) return KS_Enabled;
166   if (LangOpts.ObjC2 && (Flags & KEYOBJC2)) return KS_Enabled;
167   if (LangOpts.ConceptsTS && (Flags & KEYCONCEPTS)) return KS_Enabled;
168   if (LangOpts.CoroutinesTS && (Flags & KEYCOROUTINES)) return KS_Enabled;
169   if (LangOpts.ModulesTS && (Flags & KEYMODULES)) return KS_Enabled;
170   if (LangOpts.CPlusPlus && (Flags & KEYALLCXX)) return KS_Future;
171   return KS_Disabled;
172 }
173 
174 /// AddKeyword - This method is used to associate a token ID with specific
175 /// identifiers because they are language keywords.  This causes the lexer to
176 /// automatically map matching identifiers to specialized token codes.
177 static void AddKeyword(StringRef Keyword,
178                        tok::TokenKind TokenCode, unsigned Flags,
179                        const LangOptions &LangOpts, IdentifierTable &Table) {
180   KeywordStatus AddResult = getKeywordStatus(LangOpts, Flags);
181 
182   // Don't add this keyword under MSVCCompat.
183   if (LangOpts.MSVCCompat && (Flags & KEYNOMS18) &&
184       !LangOpts.isCompatibleWithMSVC(LangOptions::MSVC2015))
185     return;
186 
187   // Don't add this keyword under OpenCL.
188   if (LangOpts.OpenCL && (Flags & KEYNOOPENCL))
189     return;
190 
191   // Don't add this keyword if disabled in this language.
192   if (AddResult == KS_Disabled) return;
193 
194   IdentifierInfo &Info =
195       Table.get(Keyword, AddResult == KS_Future ? tok::identifier : TokenCode);
196   Info.setIsExtensionToken(AddResult == KS_Extension);
197   Info.setIsFutureCompatKeyword(AddResult == KS_Future);
198 }
199 
200 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
201 /// representations.
202 static void AddCXXOperatorKeyword(StringRef Keyword,
203                                   tok::TokenKind TokenCode,
204                                   IdentifierTable &Table) {
205   IdentifierInfo &Info = Table.get(Keyword, TokenCode);
206   Info.setIsCPlusPlusOperatorKeyword();
207 }
208 
209 /// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
210 /// or "property".
211 static void AddObjCKeyword(StringRef Name,
212                            tok::ObjCKeywordKind ObjCID,
213                            IdentifierTable &Table) {
214   Table.get(Name).setObjCKeywordID(ObjCID);
215 }
216 
217 /// AddKeywords - Add all keywords to the symbol table.
218 ///
219 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
220   // Add keywords and tokens for the current language.
221 #define KEYWORD(NAME, FLAGS) \
222   AddKeyword(StringRef(#NAME), tok::kw_ ## NAME,  \
223              FLAGS, LangOpts, *this);
224 #define ALIAS(NAME, TOK, FLAGS) \
225   AddKeyword(StringRef(NAME), tok::kw_ ## TOK,  \
226              FLAGS, LangOpts, *this);
227 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
228   if (LangOpts.CXXOperatorNames)          \
229     AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
230 #define OBJC1_AT_KEYWORD(NAME) \
231   if (LangOpts.ObjC1)          \
232     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
233 #define OBJC2_AT_KEYWORD(NAME) \
234   if (LangOpts.ObjC2)          \
235     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
236 #define TESTING_KEYWORD(NAME, FLAGS)
237 #include "clang/Basic/TokenKinds.def"
238 
239   if (LangOpts.ParseUnknownAnytype)
240     AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
241                LangOpts, *this);
242 
243   if (LangOpts.DeclSpecKeyword)
244     AddKeyword("__declspec", tok::kw___declspec, KEYALL, LangOpts, *this);
245 
246   // Add the '_experimental_modules_import' contextual keyword.
247   get("import").setModulesImport(true);
248 }
249 
250 /// Checks if the specified token kind represents a keyword in the
251 /// specified language.
252 /// \returns Status of the keyword in the language.
253 static KeywordStatus getTokenKwStatus(const LangOptions &LangOpts,
254                                       tok::TokenKind K) {
255   switch (K) {
256 #define KEYWORD(NAME, FLAGS) \
257   case tok::kw_##NAME: return getKeywordStatus(LangOpts, FLAGS);
258 #include "clang/Basic/TokenKinds.def"
259   default: return KS_Disabled;
260   }
261 }
262 
263 /// Returns true if the identifier represents a keyword in the
264 /// specified language.
265 bool IdentifierInfo::isKeyword(const LangOptions &LangOpts) const {
266   switch (getTokenKwStatus(LangOpts, getTokenID())) {
267   case KS_Enabled:
268   case KS_Extension:
269     return true;
270   default:
271     return false;
272   }
273 }
274 
275 /// Returns true if the identifier represents a C++ keyword in the
276 /// specified language.
277 bool IdentifierInfo::isCPlusPlusKeyword(const LangOptions &LangOpts) const {
278   if (!LangOpts.CPlusPlus || !isKeyword(LangOpts))
279     return false;
280   // This is a C++ keyword if this identifier is not a keyword when checked
281   // using LangOptions without C++ support.
282   LangOptions LangOptsNoCPP = LangOpts;
283   LangOptsNoCPP.CPlusPlus = false;
284   LangOptsNoCPP.CPlusPlus11 = false;
285   LangOptsNoCPP.CPlusPlus2a = false;
286   return !isKeyword(LangOptsNoCPP);
287 }
288 
289 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
290   // We use a perfect hash function here involving the length of the keyword,
291   // the first and third character.  For preprocessor ID's there are no
292   // collisions (if there were, the switch below would complain about duplicate
293   // case values).  Note that this depends on 'if' being null terminated.
294 
295 #define HASH(LEN, FIRST, THIRD) \
296   (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
297 #define CASE(LEN, FIRST, THIRD, NAME) \
298   case HASH(LEN, FIRST, THIRD): \
299     return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
300 
301   unsigned Len = getLength();
302   if (Len < 2) return tok::pp_not_keyword;
303   const char *Name = getNameStart();
304   switch (HASH(Len, Name[0], Name[2])) {
305   default: return tok::pp_not_keyword;
306   CASE( 2, 'i', '\0', if);
307   CASE( 4, 'e', 'i', elif);
308   CASE( 4, 'e', 's', else);
309   CASE( 4, 'l', 'n', line);
310   CASE( 4, 's', 'c', sccs);
311   CASE( 5, 'e', 'd', endif);
312   CASE( 5, 'e', 'r', error);
313   CASE( 5, 'i', 'e', ident);
314   CASE( 5, 'i', 'd', ifdef);
315   CASE( 5, 'u', 'd', undef);
316 
317   CASE( 6, 'a', 's', assert);
318   CASE( 6, 'd', 'f', define);
319   CASE( 6, 'i', 'n', ifndef);
320   CASE( 6, 'i', 'p', import);
321   CASE( 6, 'p', 'a', pragma);
322 
323   CASE( 7, 'd', 'f', defined);
324   CASE( 7, 'i', 'c', include);
325   CASE( 7, 'w', 'r', warning);
326 
327   CASE( 8, 'u', 'a', unassert);
328   CASE(12, 'i', 'c', include_next);
329 
330   CASE(14, '_', 'p', __public_macro);
331 
332   CASE(15, '_', 'p', __private_macro);
333 
334   CASE(16, '_', 'i', __include_macros);
335 #undef CASE
336 #undef HASH
337   }
338 }
339 
340 //===----------------------------------------------------------------------===//
341 // Stats Implementation
342 //===----------------------------------------------------------------------===//
343 
344 /// PrintStats - Print statistics about how well the identifier table is doing
345 /// at hashing identifiers.
346 void IdentifierTable::PrintStats() const {
347   unsigned NumBuckets = HashTable.getNumBuckets();
348   unsigned NumIdentifiers = HashTable.getNumItems();
349   unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
350   unsigned AverageIdentifierSize = 0;
351   unsigned MaxIdentifierLength = 0;
352 
353   // TODO: Figure out maximum times an identifier had to probe for -stats.
354   for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
355        I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
356     unsigned IdLen = I->getKeyLength();
357     AverageIdentifierSize += IdLen;
358     if (MaxIdentifierLength < IdLen)
359       MaxIdentifierLength = IdLen;
360   }
361 
362   fprintf(stderr, "\n*** Identifier Table Stats:\n");
363   fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
364   fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
365   fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
366           NumIdentifiers/(double)NumBuckets);
367   fprintf(stderr, "Ave identifier length: %f\n",
368           (AverageIdentifierSize/(double)NumIdentifiers));
369   fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
370 
371   // Compute statistics about the memory allocated for identifiers.
372   HashTable.getAllocator().PrintStats();
373 }
374 
375 //===----------------------------------------------------------------------===//
376 // SelectorTable Implementation
377 //===----------------------------------------------------------------------===//
378 
379 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
380   return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
381 }
382 
383 namespace clang {
384 
385 /// One of these variable length records is kept for each
386 /// selector containing more than one keyword. We use a folding set
387 /// to unique aggregate names (keyword selectors in ObjC parlance). Access to
388 /// this class is provided strictly through Selector.
389 class alignas(IdentifierInfoAlignment) MultiKeywordSelector
390     : public detail::DeclarationNameExtra,
391       public llvm::FoldingSetNode {
392   MultiKeywordSelector(unsigned nKeys) : DeclarationNameExtra(nKeys) {}
393 
394 public:
395   // Constructor for keyword selectors.
396   MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV)
397       : DeclarationNameExtra(nKeys) {
398     assert((nKeys > 1) && "not a multi-keyword selector");
399 
400     // Fill in the trailing keyword array.
401     IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this + 1);
402     for (unsigned i = 0; i != nKeys; ++i)
403       KeyInfo[i] = IIV[i];
404   }
405 
406   // getName - Derive the full selector name and return it.
407   std::string getName() const;
408 
409   using DeclarationNameExtra::getNumArgs;
410 
411   using keyword_iterator = IdentifierInfo *const *;
412 
413   keyword_iterator keyword_begin() const {
414     return reinterpret_cast<keyword_iterator>(this + 1);
415   }
416 
417   keyword_iterator keyword_end() const {
418     return keyword_begin() + getNumArgs();
419   }
420 
421   IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
422     assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
423     return keyword_begin()[i];
424   }
425 
426   static void Profile(llvm::FoldingSetNodeID &ID, keyword_iterator ArgTys,
427                       unsigned NumArgs) {
428     ID.AddInteger(NumArgs);
429     for (unsigned i = 0; i != NumArgs; ++i)
430       ID.AddPointer(ArgTys[i]);
431   }
432 
433   void Profile(llvm::FoldingSetNodeID &ID) {
434     Profile(ID, keyword_begin(), getNumArgs());
435   }
436 };
437 
438 } // namespace clang.
439 
440 unsigned Selector::getNumArgs() const {
441   unsigned IIF = getIdentifierInfoFlag();
442   if (IIF <= ZeroArg)
443     return 0;
444   if (IIF == OneArg)
445     return 1;
446   // We point to a MultiKeywordSelector.
447   MultiKeywordSelector *SI = getMultiKeywordSelector();
448   return SI->getNumArgs();
449 }
450 
451 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
452   if (getIdentifierInfoFlag() < MultiArg) {
453     assert(argIndex == 0 && "illegal keyword index");
454     return getAsIdentifierInfo();
455   }
456 
457   // We point to a MultiKeywordSelector.
458   MultiKeywordSelector *SI = getMultiKeywordSelector();
459   return SI->getIdentifierInfoForSlot(argIndex);
460 }
461 
462 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
463   IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
464   return II ? II->getName() : StringRef();
465 }
466 
467 std::string MultiKeywordSelector::getName() const {
468   SmallString<256> Str;
469   llvm::raw_svector_ostream OS(Str);
470   for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
471     if (*I)
472       OS << (*I)->getName();
473     OS << ':';
474   }
475 
476   return OS.str();
477 }
478 
479 std::string Selector::getAsString() const {
480   if (InfoPtr == 0)
481     return "<null selector>";
482 
483   if (getIdentifierInfoFlag() < MultiArg) {
484     IdentifierInfo *II = getAsIdentifierInfo();
485 
486     if (getNumArgs() == 0) {
487       assert(II && "If the number of arguments is 0 then II is guaranteed to "
488                    "not be null.");
489       return II->getName();
490     }
491 
492     if (!II)
493       return ":";
494 
495     return II->getName().str() + ":";
496   }
497 
498   // We have a multiple keyword selector.
499   return getMultiKeywordSelector()->getName();
500 }
501 
502 void Selector::print(llvm::raw_ostream &OS) const {
503   OS << getAsString();
504 }
505 
506 LLVM_DUMP_METHOD void Selector::dump() const { print(llvm::errs()); }
507 
508 /// Interpreting the given string using the normal CamelCase
509 /// conventions, determine whether the given string starts with the
510 /// given "word", which is assumed to end in a lowercase letter.
511 static bool startsWithWord(StringRef name, StringRef word) {
512   if (name.size() < word.size()) return false;
513   return ((name.size() == word.size() || !isLowercase(name[word.size()])) &&
514           name.startswith(word));
515 }
516 
517 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
518   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
519   if (!first) return OMF_None;
520 
521   StringRef name = first->getName();
522   if (sel.isUnarySelector()) {
523     if (name == "autorelease") return OMF_autorelease;
524     if (name == "dealloc") return OMF_dealloc;
525     if (name == "finalize") return OMF_finalize;
526     if (name == "release") return OMF_release;
527     if (name == "retain") return OMF_retain;
528     if (name == "retainCount") return OMF_retainCount;
529     if (name == "self") return OMF_self;
530     if (name == "initialize") return OMF_initialize;
531   }
532 
533   if (name == "performSelector" || name == "performSelectorInBackground" ||
534       name == "performSelectorOnMainThread")
535     return OMF_performSelector;
536 
537   // The other method families may begin with a prefix of underscores.
538   while (!name.empty() && name.front() == '_')
539     name = name.substr(1);
540 
541   if (name.empty()) return OMF_None;
542   switch (name.front()) {
543   case 'a':
544     if (startsWithWord(name, "alloc")) return OMF_alloc;
545     break;
546   case 'c':
547     if (startsWithWord(name, "copy")) return OMF_copy;
548     break;
549   case 'i':
550     if (startsWithWord(name, "init")) return OMF_init;
551     break;
552   case 'm':
553     if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
554     break;
555   case 'n':
556     if (startsWithWord(name, "new")) return OMF_new;
557     break;
558   default:
559     break;
560   }
561 
562   return OMF_None;
563 }
564 
565 ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
566   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
567   if (!first) return OIT_None;
568 
569   StringRef name = first->getName();
570 
571   if (name.empty()) return OIT_None;
572   switch (name.front()) {
573     case 'a':
574       if (startsWithWord(name, "array")) return OIT_Array;
575       break;
576     case 'd':
577       if (startsWithWord(name, "default")) return OIT_ReturnsSelf;
578       if (startsWithWord(name, "dictionary")) return OIT_Dictionary;
579       break;
580     case 's':
581       if (startsWithWord(name, "shared")) return OIT_ReturnsSelf;
582       if (startsWithWord(name, "standard")) return OIT_Singleton;
583       break;
584     case 'i':
585       if (startsWithWord(name, "init")) return OIT_Init;
586     default:
587       break;
588   }
589   return OIT_None;
590 }
591 
592 ObjCStringFormatFamily Selector::getStringFormatFamilyImpl(Selector sel) {
593   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
594   if (!first) return SFF_None;
595 
596   StringRef name = first->getName();
597 
598   switch (name.front()) {
599     case 'a':
600       if (name == "appendFormat") return SFF_NSString;
601       break;
602 
603     case 'i':
604       if (name == "initWithFormat") return SFF_NSString;
605       break;
606 
607     case 'l':
608       if (name == "localizedStringWithFormat") return SFF_NSString;
609       break;
610 
611     case 's':
612       if (name == "stringByAppendingFormat" ||
613           name == "stringWithFormat") return SFF_NSString;
614       break;
615   }
616   return SFF_None;
617 }
618 
619 namespace {
620 
621 struct SelectorTableImpl {
622   llvm::FoldingSet<MultiKeywordSelector> Table;
623   llvm::BumpPtrAllocator Allocator;
624 };
625 
626 } // namespace
627 
628 static SelectorTableImpl &getSelectorTableImpl(void *P) {
629   return *static_cast<SelectorTableImpl*>(P);
630 }
631 
632 SmallString<64>
633 SelectorTable::constructSetterName(StringRef Name) {
634   SmallString<64> SetterName("set");
635   SetterName += Name;
636   SetterName[3] = toUppercase(SetterName[3]);
637   return SetterName;
638 }
639 
640 Selector
641 SelectorTable::constructSetterSelector(IdentifierTable &Idents,
642                                        SelectorTable &SelTable,
643                                        const IdentifierInfo *Name) {
644   IdentifierInfo *SetterName =
645     &Idents.get(constructSetterName(Name->getName()));
646   return SelTable.getUnarySelector(SetterName);
647 }
648 
649 std::string SelectorTable::getPropertyNameFromSetterSelector(Selector Sel) {
650   StringRef Name = Sel.getNameForSlot(0);
651   assert(Name.startswith("set") && "invalid setter name");
652   return (Twine(toLowercase(Name[3])) + Name.drop_front(4)).str();
653 }
654 
655 size_t SelectorTable::getTotalMemory() const {
656   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
657   return SelTabImpl.Allocator.getTotalMemory();
658 }
659 
660 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
661   if (nKeys < 2)
662     return Selector(IIV[0], nKeys);
663 
664   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
665 
666   // Unique selector, to guarantee there is one per name.
667   llvm::FoldingSetNodeID ID;
668   MultiKeywordSelector::Profile(ID, IIV, nKeys);
669 
670   void *InsertPos = nullptr;
671   if (MultiKeywordSelector *SI =
672         SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
673     return Selector(SI);
674 
675   // MultiKeywordSelector objects are not allocated with new because they have a
676   // variable size array (for parameter types) at the end of them.
677   unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
678   MultiKeywordSelector *SI =
679       (MultiKeywordSelector *)SelTabImpl.Allocator.Allocate(
680           Size, alignof(MultiKeywordSelector));
681   new (SI) MultiKeywordSelector(nKeys, IIV);
682   SelTabImpl.Table.InsertNode(SI, InsertPos);
683   return Selector(SI);
684 }
685 
686 SelectorTable::SelectorTable() {
687   Impl = new SelectorTableImpl();
688 }
689 
690 SelectorTable::~SelectorTable() {
691   delete &getSelectorTableImpl(Impl);
692 }
693 
694 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
695   switch (Operator) {
696   case OO_None:
697   case NUM_OVERLOADED_OPERATORS:
698     return nullptr;
699 
700 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
701   case OO_##Name: return Spelling;
702 #include "clang/Basic/OperatorKinds.def"
703   }
704 
705   llvm_unreachable("Invalid OverloadedOperatorKind!");
706 }
707 
708 StringRef clang::getNullabilitySpelling(NullabilityKind kind,
709                                         bool isContextSensitive) {
710   switch (kind) {
711   case NullabilityKind::NonNull:
712     return isContextSensitive ? "nonnull" : "_Nonnull";
713 
714   case NullabilityKind::Nullable:
715     return isContextSensitive ? "nullable" : "_Nullable";
716 
717   case NullabilityKind::Unspecified:
718     return isContextSensitive ? "null_unspecified" : "_Null_unspecified";
719   }
720   llvm_unreachable("Unknown nullability kind.");
721 }
722