1 //===- IdentifierTable.cpp - Hash table for identifier lookup -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the IdentifierInfo, IdentifierVisitor, and
11 // IdentifierTable interfaces.
13 //===----------------------------------------------------------------------===//
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"
34 using namespace clang;
36 //===----------------------------------------------------------------------===//
37 // IdentifierInfo Implementation
38 //===----------------------------------------------------------------------===//
40 IdentifierInfo::IdentifierInfo() {
41 TokenID = tok::identifier;
46 IsFutureCompatKeyword = false;
48 IsCPPOperatorKeyword = false;
49 NeedsHandleIdentifier = false;
51 ChangedAfterLoad = false;
52 FEChangedAfterLoad = false;
53 RevertedTokenID = false;
55 IsModulesImport = false;
58 //===----------------------------------------------------------------------===//
59 // IdentifierTable Implementation
60 //===----------------------------------------------------------------------===//
62 IdentifierIterator::~IdentifierIterator() = default;
64 IdentifierInfoLookup::~IdentifierInfoLookup() = default;
68 /// \brief A simple identifier lookup iterator that represents an
69 /// empty sequence of identifiers.
70 class EmptyLookupIterator : public IdentifierIterator
73 StringRef Next() override { return StringRef(); }
78 IdentifierIterator *IdentifierInfoLookup::getIdentifiers() {
79 return new EmptyLookupIterator();
82 IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
83 IdentifierInfoLookup* externalLookup)
84 : HashTable(8192), // Start with space for 8K identifiers.
85 ExternalLookup(externalLookup) {
86 // Populate the identifier table with info about keywords for the current
88 AddKeywords(LangOpts);
90 // Add the '_experimental_modules_import' contextual keyword.
91 get("import").setModulesImport(true);
94 //===----------------------------------------------------------------------===//
95 // Language Keyword Implementation
96 //===----------------------------------------------------------------------===//
98 // Constants for TokenKinds.def
115 KEYNOOPENCL = 0x02000,
116 WCHARSUPPORT = 0x04000,
117 HALFSUPPORT = 0x08000,
118 KEYCONCEPTS = 0x10000,
120 KEYZVECTOR = 0x40000,
121 KEYCOROUTINES = 0x80000,
122 KEYMODULES = 0x100000,
124 KEYALLCXX = KEYCXX | KEYCXX11 | KEYCXX2A,
125 KEYALL = (0x3fffff & ~KEYNOMS18 &
126 ~KEYNOOPENCL) // KEYNOMS18 and KEYNOOPENCL are used to exclude.
129 /// \brief How a keyword is treated in the selected standard.
131 KS_Disabled, // Disabled
132 KS_Extension, // Is an extension
133 KS_Enabled, // Enabled
134 KS_Future // Is a keyword in future standard
139 /// \brief Translates flags as specified in TokenKinds.def into keyword status
140 /// in the given language standard.
141 static KeywordStatus getKeywordStatus(const LangOptions &LangOpts,
143 if (Flags == KEYALL) return KS_Enabled;
144 if (LangOpts.CPlusPlus && (Flags & KEYCXX)) return KS_Enabled;
145 if (LangOpts.CPlusPlus11 && (Flags & KEYCXX11)) return KS_Enabled;
146 if (LangOpts.CPlusPlus2a && (Flags & KEYCXX2A)) return KS_Enabled;
147 if (LangOpts.C99 && (Flags & KEYC99)) return KS_Enabled;
148 if (LangOpts.GNUKeywords && (Flags & KEYGNU)) return KS_Extension;
149 if (LangOpts.MicrosoftExt && (Flags & KEYMS)) return KS_Extension;
150 if (LangOpts.Borland && (Flags & KEYBORLAND)) return KS_Extension;
151 if (LangOpts.Bool && (Flags & BOOLSUPPORT)) return KS_Enabled;
152 if (LangOpts.Half && (Flags & HALFSUPPORT)) return KS_Enabled;
153 if (LangOpts.WChar && (Flags & WCHARSUPPORT)) return KS_Enabled;
154 if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) return KS_Enabled;
155 if (LangOpts.OpenCL && (Flags & KEYOPENCL)) return KS_Enabled;
156 if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) return KS_Enabled;
157 if (LangOpts.C11 && (Flags & KEYC11)) return KS_Enabled;
158 // We treat bridge casts as objective-C keywords so we can warn on them
160 if (LangOpts.ObjC2 && (Flags & KEYARC)) return KS_Enabled;
161 if (LangOpts.ObjC2 && (Flags & KEYOBJC2)) return KS_Enabled;
162 if (LangOpts.ConceptsTS && (Flags & KEYCONCEPTS)) return KS_Enabled;
163 if (LangOpts.CoroutinesTS && (Flags & KEYCOROUTINES)) return KS_Enabled;
164 if (LangOpts.ModulesTS && (Flags & KEYMODULES)) return KS_Enabled;
165 if (LangOpts.CPlusPlus && (Flags & KEYALLCXX)) return KS_Future;
169 /// AddKeyword - This method is used to associate a token ID with specific
170 /// identifiers because they are language keywords. This causes the lexer to
171 /// automatically map matching identifiers to specialized token codes.
172 static void AddKeyword(StringRef Keyword,
173 tok::TokenKind TokenCode, unsigned Flags,
174 const LangOptions &LangOpts, IdentifierTable &Table) {
175 KeywordStatus AddResult = getKeywordStatus(LangOpts, Flags);
177 // Don't add this keyword under MSVCCompat.
178 if (LangOpts.MSVCCompat && (Flags & KEYNOMS18) &&
179 !LangOpts.isCompatibleWithMSVC(LangOptions::MSVC2015))
182 // Don't add this keyword under OpenCL.
183 if (LangOpts.OpenCL && (Flags & KEYNOOPENCL))
186 // Don't add this keyword if disabled in this language.
187 if (AddResult == KS_Disabled) return;
189 IdentifierInfo &Info =
190 Table.get(Keyword, AddResult == KS_Future ? tok::identifier : TokenCode);
191 Info.setIsExtensionToken(AddResult == KS_Extension);
192 Info.setIsFutureCompatKeyword(AddResult == KS_Future);
195 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
197 static void AddCXXOperatorKeyword(StringRef Keyword,
198 tok::TokenKind TokenCode,
199 IdentifierTable &Table) {
200 IdentifierInfo &Info = Table.get(Keyword, TokenCode);
201 Info.setIsCPlusPlusOperatorKeyword();
204 /// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
206 static void AddObjCKeyword(StringRef Name,
207 tok::ObjCKeywordKind ObjCID,
208 IdentifierTable &Table) {
209 Table.get(Name).setObjCKeywordID(ObjCID);
212 /// AddKeywords - Add all keywords to the symbol table.
214 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
215 // Add keywords and tokens for the current language.
216 #define KEYWORD(NAME, FLAGS) \
217 AddKeyword(StringRef(#NAME), tok::kw_ ## NAME, \
218 FLAGS, LangOpts, *this);
219 #define ALIAS(NAME, TOK, FLAGS) \
220 AddKeyword(StringRef(NAME), tok::kw_ ## TOK, \
221 FLAGS, LangOpts, *this);
222 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
223 if (LangOpts.CXXOperatorNames) \
224 AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
225 #define OBJC1_AT_KEYWORD(NAME) \
226 if (LangOpts.ObjC1) \
227 AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
228 #define OBJC2_AT_KEYWORD(NAME) \
229 if (LangOpts.ObjC2) \
230 AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
231 #define TESTING_KEYWORD(NAME, FLAGS)
232 #include "clang/Basic/TokenKinds.def"
234 if (LangOpts.ParseUnknownAnytype)
235 AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
238 if (LangOpts.DeclSpecKeyword)
239 AddKeyword("__declspec", tok::kw___declspec, KEYALL, LangOpts, *this);
242 /// \brief Checks if the specified token kind represents a keyword in the
243 /// specified language.
244 /// \returns Status of the keyword in the language.
245 static KeywordStatus getTokenKwStatus(const LangOptions &LangOpts,
248 #define KEYWORD(NAME, FLAGS) \
249 case tok::kw_##NAME: return getKeywordStatus(LangOpts, FLAGS);
250 #include "clang/Basic/TokenKinds.def"
251 default: return KS_Disabled;
255 /// \brief Returns true if the identifier represents a keyword in the
256 /// specified language.
257 bool IdentifierInfo::isKeyword(const LangOptions &LangOpts) const {
258 switch (getTokenKwStatus(LangOpts, getTokenID())) {
267 /// \brief Returns true if the identifier represents a C++ keyword in the
268 /// specified language.
269 bool IdentifierInfo::isCPlusPlusKeyword(const LangOptions &LangOpts) const {
270 if (!LangOpts.CPlusPlus || !isKeyword(LangOpts))
272 // This is a C++ keyword if this identifier is not a keyword when checked
273 // using LangOptions without C++ support.
274 LangOptions LangOptsNoCPP = LangOpts;
275 LangOptsNoCPP.CPlusPlus = false;
276 LangOptsNoCPP.CPlusPlus11 = false;
277 LangOptsNoCPP.CPlusPlus2a = false;
278 return !isKeyword(LangOptsNoCPP);
281 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
282 // We use a perfect hash function here involving the length of the keyword,
283 // the first and third character. For preprocessor ID's there are no
284 // collisions (if there were, the switch below would complain about duplicate
285 // case values). Note that this depends on 'if' being null terminated.
287 #define HASH(LEN, FIRST, THIRD) \
288 (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
289 #define CASE(LEN, FIRST, THIRD, NAME) \
290 case HASH(LEN, FIRST, THIRD): \
291 return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
293 unsigned Len = getLength();
294 if (Len < 2) return tok::pp_not_keyword;
295 const char *Name = getNameStart();
296 switch (HASH(Len, Name[0], Name[2])) {
297 default: return tok::pp_not_keyword;
298 CASE( 2, 'i', '\0', if);
299 CASE( 4, 'e', 'i', elif);
300 CASE( 4, 'e', 's', else);
301 CASE( 4, 'l', 'n', line);
302 CASE( 4, 's', 'c', sccs);
303 CASE( 5, 'e', 'd', endif);
304 CASE( 5, 'e', 'r', error);
305 CASE( 5, 'i', 'e', ident);
306 CASE( 5, 'i', 'd', ifdef);
307 CASE( 5, 'u', 'd', undef);
309 CASE( 6, 'a', 's', assert);
310 CASE( 6, 'd', 'f', define);
311 CASE( 6, 'i', 'n', ifndef);
312 CASE( 6, 'i', 'p', import);
313 CASE( 6, 'p', 'a', pragma);
315 CASE( 7, 'd', 'f', defined);
316 CASE( 7, 'i', 'c', include);
317 CASE( 7, 'w', 'r', warning);
319 CASE( 8, 'u', 'a', unassert);
320 CASE(12, 'i', 'c', include_next);
322 CASE(14, '_', 'p', __public_macro);
324 CASE(15, '_', 'p', __private_macro);
326 CASE(16, '_', 'i', __include_macros);
332 //===----------------------------------------------------------------------===//
333 // Stats Implementation
334 //===----------------------------------------------------------------------===//
336 /// PrintStats - Print statistics about how well the identifier table is doing
337 /// at hashing identifiers.
338 void IdentifierTable::PrintStats() const {
339 unsigned NumBuckets = HashTable.getNumBuckets();
340 unsigned NumIdentifiers = HashTable.getNumItems();
341 unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
342 unsigned AverageIdentifierSize = 0;
343 unsigned MaxIdentifierLength = 0;
345 // TODO: Figure out maximum times an identifier had to probe for -stats.
346 for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
347 I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
348 unsigned IdLen = I->getKeyLength();
349 AverageIdentifierSize += IdLen;
350 if (MaxIdentifierLength < IdLen)
351 MaxIdentifierLength = IdLen;
354 fprintf(stderr, "\n*** Identifier Table Stats:\n");
355 fprintf(stderr, "# Identifiers: %d\n", NumIdentifiers);
356 fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
357 fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
358 NumIdentifiers/(double)NumBuckets);
359 fprintf(stderr, "Ave identifier length: %f\n",
360 (AverageIdentifierSize/(double)NumIdentifiers));
361 fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
363 // Compute statistics about the memory allocated for identifiers.
364 HashTable.getAllocator().PrintStats();
367 //===----------------------------------------------------------------------===//
368 // SelectorTable Implementation
369 //===----------------------------------------------------------------------===//
371 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
372 return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
377 /// MultiKeywordSelector - One of these variable length records is kept for each
378 /// selector containing more than one keyword. We use a folding set
379 /// to unique aggregate names (keyword selectors in ObjC parlance). Access to
380 /// this class is provided strictly through Selector.
381 class MultiKeywordSelector
382 : public DeclarationNameExtra, public llvm::FoldingSetNode {
383 MultiKeywordSelector(unsigned nKeys) {
384 ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
388 // Constructor for keyword selectors.
389 MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV) {
390 assert((nKeys > 1) && "not a multi-keyword selector");
391 ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
393 // Fill in the trailing keyword array.
394 IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1);
395 for (unsigned i = 0; i != nKeys; ++i)
399 // getName - Derive the full selector name and return it.
400 std::string getName() const;
402 unsigned getNumArgs() const { return ExtraKindOrNumArgs - NUM_EXTRA_KINDS; }
404 using keyword_iterator = IdentifierInfo *const *;
406 keyword_iterator keyword_begin() const {
407 return reinterpret_cast<keyword_iterator>(this+1);
410 keyword_iterator keyword_end() const {
411 return keyword_begin()+getNumArgs();
414 IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
415 assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
416 return keyword_begin()[i];
419 static void Profile(llvm::FoldingSetNodeID &ID,
420 keyword_iterator ArgTys, unsigned NumArgs) {
421 ID.AddInteger(NumArgs);
422 for (unsigned i = 0; i != NumArgs; ++i)
423 ID.AddPointer(ArgTys[i]);
426 void Profile(llvm::FoldingSetNodeID &ID) {
427 Profile(ID, keyword_begin(), getNumArgs());
431 } // namespace clang.
433 unsigned Selector::getNumArgs() const {
434 unsigned IIF = getIdentifierInfoFlag();
439 // We point to a MultiKeywordSelector.
440 MultiKeywordSelector *SI = getMultiKeywordSelector();
441 return SI->getNumArgs();
444 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
445 if (getIdentifierInfoFlag() < MultiArg) {
446 assert(argIndex == 0 && "illegal keyword index");
447 return getAsIdentifierInfo();
450 // We point to a MultiKeywordSelector.
451 MultiKeywordSelector *SI = getMultiKeywordSelector();
452 return SI->getIdentifierInfoForSlot(argIndex);
455 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
456 IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
457 return II? II->getName() : StringRef();
460 std::string MultiKeywordSelector::getName() const {
461 SmallString<256> Str;
462 llvm::raw_svector_ostream OS(Str);
463 for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
465 OS << (*I)->getName();
472 std::string Selector::getAsString() const {
474 return "<null selector>";
476 if (getIdentifierInfoFlag() < MultiArg) {
477 IdentifierInfo *II = getAsIdentifierInfo();
479 if (getNumArgs() == 0) {
480 assert(II && "If the number of arguments is 0 then II is guaranteed to "
482 return II->getName();
488 return II->getName().str() + ":";
491 // We have a multiple keyword selector.
492 return getMultiKeywordSelector()->getName();
495 void Selector::print(llvm::raw_ostream &OS) const {
499 /// Interpreting the given string using the normal CamelCase
500 /// conventions, determine whether the given string starts with the
501 /// given "word", which is assumed to end in a lowercase letter.
502 static bool startsWithWord(StringRef name, StringRef word) {
503 if (name.size() < word.size()) return false;
504 return ((name.size() == word.size() || !isLowercase(name[word.size()])) &&
505 name.startswith(word));
508 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
509 IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
510 if (!first) return OMF_None;
512 StringRef name = first->getName();
513 if (sel.isUnarySelector()) {
514 if (name == "autorelease") return OMF_autorelease;
515 if (name == "dealloc") return OMF_dealloc;
516 if (name == "finalize") return OMF_finalize;
517 if (name == "release") return OMF_release;
518 if (name == "retain") return OMF_retain;
519 if (name == "retainCount") return OMF_retainCount;
520 if (name == "self") return OMF_self;
521 if (name == "initialize") return OMF_initialize;
524 if (name == "performSelector" || name == "performSelectorInBackground" ||
525 name == "performSelectorOnMainThread")
526 return OMF_performSelector;
528 // The other method families may begin with a prefix of underscores.
529 while (!name.empty() && name.front() == '_')
530 name = name.substr(1);
532 if (name.empty()) return OMF_None;
533 switch (name.front()) {
535 if (startsWithWord(name, "alloc")) return OMF_alloc;
538 if (startsWithWord(name, "copy")) return OMF_copy;
541 if (startsWithWord(name, "init")) return OMF_init;
544 if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
547 if (startsWithWord(name, "new")) return OMF_new;
556 ObjCInstanceTypeFamily Selector::getInstTypeMethodFamily(Selector sel) {
557 IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
558 if (!first) return OIT_None;
560 StringRef name = first->getName();
562 if (name.empty()) return OIT_None;
563 switch (name.front()) {
565 if (startsWithWord(name, "array")) return OIT_Array;
568 if (startsWithWord(name, "default")) return OIT_ReturnsSelf;
569 if (startsWithWord(name, "dictionary")) return OIT_Dictionary;
572 if (startsWithWord(name, "shared")) return OIT_ReturnsSelf;
573 if (startsWithWord(name, "standard")) return OIT_Singleton;
576 if (startsWithWord(name, "init")) return OIT_Init;
583 ObjCStringFormatFamily Selector::getStringFormatFamilyImpl(Selector sel) {
584 IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
585 if (!first) return SFF_None;
587 StringRef name = first->getName();
589 switch (name.front()) {
591 if (name == "appendFormat") return SFF_NSString;
595 if (name == "initWithFormat") return SFF_NSString;
599 if (name == "localizedStringWithFormat") return SFF_NSString;
603 if (name == "stringByAppendingFormat" ||
604 name == "stringWithFormat") return SFF_NSString;
612 struct SelectorTableImpl {
613 llvm::FoldingSet<MultiKeywordSelector> Table;
614 llvm::BumpPtrAllocator Allocator;
619 static SelectorTableImpl &getSelectorTableImpl(void *P) {
620 return *static_cast<SelectorTableImpl*>(P);
624 SelectorTable::constructSetterName(StringRef Name) {
625 SmallString<64> SetterName("set");
627 SetterName[3] = toUppercase(SetterName[3]);
632 SelectorTable::constructSetterSelector(IdentifierTable &Idents,
633 SelectorTable &SelTable,
634 const IdentifierInfo *Name) {
635 IdentifierInfo *SetterName =
636 &Idents.get(constructSetterName(Name->getName()));
637 return SelTable.getUnarySelector(SetterName);
640 size_t SelectorTable::getTotalMemory() const {
641 SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
642 return SelTabImpl.Allocator.getTotalMemory();
645 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
647 return Selector(IIV[0], nKeys);
649 SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
651 // Unique selector, to guarantee there is one per name.
652 llvm::FoldingSetNodeID ID;
653 MultiKeywordSelector::Profile(ID, IIV, nKeys);
655 void *InsertPos = nullptr;
656 if (MultiKeywordSelector *SI =
657 SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
660 // MultiKeywordSelector objects are not allocated with new because they have a
661 // variable size array (for parameter types) at the end of them.
662 unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
663 MultiKeywordSelector *SI =
664 (MultiKeywordSelector *)SelTabImpl.Allocator.Allocate(
665 Size, alignof(MultiKeywordSelector));
666 new (SI) MultiKeywordSelector(nKeys, IIV);
667 SelTabImpl.Table.InsertNode(SI, InsertPos);
671 SelectorTable::SelectorTable() {
672 Impl = new SelectorTableImpl();
675 SelectorTable::~SelectorTable() {
676 delete &getSelectorTableImpl(Impl);
679 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
682 case NUM_OVERLOADED_OPERATORS:
685 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
686 case OO_##Name: return Spelling;
687 #include "clang/Basic/OperatorKinds.def"
690 llvm_unreachable("Invalid OverloadedOperatorKind!");
693 StringRef clang::getNullabilitySpelling(NullabilityKind kind,
694 bool isContextSensitive) {
696 case NullabilityKind::NonNull:
697 return isContextSensitive ? "nonnull" : "_Nonnull";
699 case NullabilityKind::Nullable:
700 return isContextSensitive ? "nullable" : "_Nullable";
702 case NullabilityKind::Unspecified:
703 return isContextSensitive ? "null_unspecified" : "_Null_unspecified";
705 llvm_unreachable("Unknown nullability kind.");