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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/LangOptions.h"
17 #include "llvm/ADT/FoldingSet.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/StringSwitch.h"
21 #include "llvm/Support/raw_ostream.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include <cctype>
24 #include <cstdio>
25 
26 using namespace clang;
27 
28 //===----------------------------------------------------------------------===//
29 // IdentifierInfo Implementation
30 //===----------------------------------------------------------------------===//
31 
IdentifierInfo()32 IdentifierInfo::IdentifierInfo() {
33   TokenID = tok::identifier;
34   ObjCOrBuiltinID = 0;
35   HasMacro = false;
36   IsExtension = false;
37   IsCXX11CompatKeyword = false;
38   IsPoisoned = false;
39   IsCPPOperatorKeyword = false;
40   NeedsHandleIdentifier = false;
41   IsFromAST = false;
42   ChangedAfterLoad = false;
43   RevertedTokenID = false;
44   OutOfDate = false;
45   IsModulesImport = false;
46   FETokenInfo = 0;
47   Entry = 0;
48 }
49 
50 //===----------------------------------------------------------------------===//
51 // IdentifierTable Implementation
52 //===----------------------------------------------------------------------===//
53 
~IdentifierIterator()54 IdentifierIterator::~IdentifierIterator() { }
55 
~IdentifierInfoLookup()56 IdentifierInfoLookup::~IdentifierInfoLookup() {}
57 
58 namespace {
59   /// \brief A simple identifier lookup iterator that represents an
60   /// empty sequence of identifiers.
61   class EmptyLookupIterator : public IdentifierIterator
62   {
63   public:
Next()64     virtual StringRef Next() { return StringRef(); }
65   };
66 }
67 
getIdentifiers() const68 IdentifierIterator *IdentifierInfoLookup::getIdentifiers() const {
69   return new EmptyLookupIterator();
70 }
71 
~ExternalIdentifierLookup()72 ExternalIdentifierLookup::~ExternalIdentifierLookup() {}
73 
IdentifierTable(const LangOptions & LangOpts,IdentifierInfoLookup * externalLookup)74 IdentifierTable::IdentifierTable(const LangOptions &LangOpts,
75                                  IdentifierInfoLookup* externalLookup)
76   : HashTable(8192), // Start with space for 8K identifiers.
77     ExternalLookup(externalLookup) {
78 
79   // Populate the identifier table with info about keywords for the current
80   // language.
81   AddKeywords(LangOpts);
82 
83 
84   // Add the '_experimental_modules_import' contextual keyword.
85   get("__experimental_modules_import").setModulesImport(true);
86 }
87 
88 //===----------------------------------------------------------------------===//
89 // Language Keyword Implementation
90 //===----------------------------------------------------------------------===//
91 
92 // Constants for TokenKinds.def
93 namespace {
94   enum {
95     KEYC99 = 0x1,
96     KEYCXX = 0x2,
97     KEYCXX0X = 0x4,
98     KEYGNU = 0x8,
99     KEYMS = 0x10,
100     BOOLSUPPORT = 0x20,
101     KEYALTIVEC = 0x40,
102     KEYNOCXX = 0x80,
103     KEYBORLAND = 0x100,
104     KEYOPENCL = 0x200,
105     KEYC11 = 0x400,
106     KEYARC = 0x800,
107     KEYNOMS = 0x01000,
108     WCHARSUPPORT = 0x02000,
109     KEYALL = (0xffff & ~KEYNOMS) // Because KEYNOMS is used to exclude.
110   };
111 }
112 
113 /// AddKeyword - This method is used to associate a token ID with specific
114 /// identifiers because they are language keywords.  This causes the lexer to
115 /// automatically map matching identifiers to specialized token codes.
116 ///
117 /// The C90/C99/CPP/CPP0x flags are set to 3 if the token is a keyword in a
118 /// future language standard, set to 2 if the token should be enabled in the
119 /// specified language, set to 1 if it is an extension in the specified
120 /// language, and set to 0 if disabled in the specified language.
AddKeyword(StringRef Keyword,tok::TokenKind TokenCode,unsigned Flags,const LangOptions & LangOpts,IdentifierTable & Table)121 static void AddKeyword(StringRef Keyword,
122                        tok::TokenKind TokenCode, unsigned Flags,
123                        const LangOptions &LangOpts, IdentifierTable &Table) {
124   unsigned AddResult = 0;
125   if (Flags == KEYALL) AddResult = 2;
126   else if (LangOpts.CPlusPlus && (Flags & KEYCXX)) AddResult = 2;
127   else if (LangOpts.CPlusPlus0x && (Flags & KEYCXX0X)) AddResult = 2;
128   else if (LangOpts.C99 && (Flags & KEYC99)) AddResult = 2;
129   else if (LangOpts.GNUKeywords && (Flags & KEYGNU)) AddResult = 1;
130   else if (LangOpts.MicrosoftExt && (Flags & KEYMS)) AddResult = 1;
131   else if (LangOpts.Borland && (Flags & KEYBORLAND)) AddResult = 1;
132   else if (LangOpts.Bool && (Flags & BOOLSUPPORT)) AddResult = 2;
133   else if (LangOpts.WChar && (Flags & WCHARSUPPORT)) AddResult = 2;
134   else if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) AddResult = 2;
135   else if (LangOpts.OpenCL && (Flags & KEYOPENCL)) AddResult = 2;
136   else if (!LangOpts.CPlusPlus && (Flags & KEYNOCXX)) AddResult = 2;
137   else if (LangOpts.C11 && (Flags & KEYC11)) AddResult = 2;
138   // We treat bridge casts as objective-C keywords so we can warn on them
139   // in non-arc mode.
140   else if (LangOpts.ObjC2 && (Flags & KEYARC)) AddResult = 2;
141   else if (LangOpts.CPlusPlus && (Flags & KEYCXX0X)) AddResult = 3;
142 
143   // Don't add this keyword under MicrosoftMode.
144   if (LangOpts.MicrosoftMode && (Flags & KEYNOMS))
145      return;
146   // Don't add this keyword if disabled in this language.
147   if (AddResult == 0) return;
148 
149   IdentifierInfo &Info =
150       Table.get(Keyword, AddResult == 3 ? tok::identifier : TokenCode);
151   Info.setIsExtensionToken(AddResult == 1);
152   Info.setIsCXX11CompatKeyword(AddResult == 3);
153 }
154 
155 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative
156 /// representations.
AddCXXOperatorKeyword(StringRef Keyword,tok::TokenKind TokenCode,IdentifierTable & Table)157 static void AddCXXOperatorKeyword(StringRef Keyword,
158                                   tok::TokenKind TokenCode,
159                                   IdentifierTable &Table) {
160   IdentifierInfo &Info = Table.get(Keyword, TokenCode);
161   Info.setIsCPlusPlusOperatorKeyword();
162 }
163 
164 /// AddObjCKeyword - Register an Objective-C \@keyword like "class" "selector"
165 /// or "property".
AddObjCKeyword(StringRef Name,tok::ObjCKeywordKind ObjCID,IdentifierTable & Table)166 static void AddObjCKeyword(StringRef Name,
167                            tok::ObjCKeywordKind ObjCID,
168                            IdentifierTable &Table) {
169   Table.get(Name).setObjCKeywordID(ObjCID);
170 }
171 
172 /// AddKeywords - Add all keywords to the symbol table.
173 ///
AddKeywords(const LangOptions & LangOpts)174 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) {
175   // Add keywords and tokens for the current language.
176 #define KEYWORD(NAME, FLAGS) \
177   AddKeyword(StringRef(#NAME), tok::kw_ ## NAME,  \
178              FLAGS, LangOpts, *this);
179 #define ALIAS(NAME, TOK, FLAGS) \
180   AddKeyword(StringRef(NAME), tok::kw_ ## TOK,  \
181              FLAGS, LangOpts, *this);
182 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \
183   if (LangOpts.CXXOperatorNames)          \
184     AddCXXOperatorKeyword(StringRef(#NAME), tok::ALIAS, *this);
185 #define OBJC1_AT_KEYWORD(NAME) \
186   if (LangOpts.ObjC1)          \
187     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
188 #define OBJC2_AT_KEYWORD(NAME) \
189   if (LangOpts.ObjC2)          \
190     AddObjCKeyword(StringRef(#NAME), tok::objc_##NAME, *this);
191 #define TESTING_KEYWORD(NAME, FLAGS)
192 #include "clang/Basic/TokenKinds.def"
193 
194   if (LangOpts.ParseUnknownAnytype)
195     AddKeyword("__unknown_anytype", tok::kw___unknown_anytype, KEYALL,
196                LangOpts, *this);
197 }
198 
getPPKeywordID() const199 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const {
200   // We use a perfect hash function here involving the length of the keyword,
201   // the first and third character.  For preprocessor ID's there are no
202   // collisions (if there were, the switch below would complain about duplicate
203   // case values).  Note that this depends on 'if' being null terminated.
204 
205 #define HASH(LEN, FIRST, THIRD) \
206   (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31)
207 #define CASE(LEN, FIRST, THIRD, NAME) \
208   case HASH(LEN, FIRST, THIRD): \
209     return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
210 
211   unsigned Len = getLength();
212   if (Len < 2) return tok::pp_not_keyword;
213   const char *Name = getNameStart();
214   switch (HASH(Len, Name[0], Name[2])) {
215   default: return tok::pp_not_keyword;
216   CASE( 2, 'i', '\0', if);
217   CASE( 4, 'e', 'i', elif);
218   CASE( 4, 'e', 's', else);
219   CASE( 4, 'l', 'n', line);
220   CASE( 4, 's', 'c', sccs);
221   CASE( 5, 'e', 'd', endif);
222   CASE( 5, 'e', 'r', error);
223   CASE( 5, 'i', 'e', ident);
224   CASE( 5, 'i', 'd', ifdef);
225   CASE( 5, 'u', 'd', undef);
226 
227   CASE( 6, 'a', 's', assert);
228   CASE( 6, 'd', 'f', define);
229   CASE( 6, 'i', 'n', ifndef);
230   CASE( 6, 'i', 'p', import);
231   CASE( 6, 'p', 'a', pragma);
232 
233   CASE( 7, 'd', 'f', defined);
234   CASE( 7, 'i', 'c', include);
235   CASE( 7, 'w', 'r', warning);
236 
237   CASE( 8, 'u', 'a', unassert);
238   CASE(12, 'i', 'c', include_next);
239 
240   CASE(14, '_', 'p', __public_macro);
241 
242   CASE(15, '_', 'p', __private_macro);
243 
244   CASE(16, '_', 'i', __include_macros);
245 #undef CASE
246 #undef HASH
247   }
248 }
249 
250 //===----------------------------------------------------------------------===//
251 // Stats Implementation
252 //===----------------------------------------------------------------------===//
253 
254 /// PrintStats - Print statistics about how well the identifier table is doing
255 /// at hashing identifiers.
PrintStats() const256 void IdentifierTable::PrintStats() const {
257   unsigned NumBuckets = HashTable.getNumBuckets();
258   unsigned NumIdentifiers = HashTable.getNumItems();
259   unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers;
260   unsigned AverageIdentifierSize = 0;
261   unsigned MaxIdentifierLength = 0;
262 
263   // TODO: Figure out maximum times an identifier had to probe for -stats.
264   for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator
265        I = HashTable.begin(), E = HashTable.end(); I != E; ++I) {
266     unsigned IdLen = I->getKeyLength();
267     AverageIdentifierSize += IdLen;
268     if (MaxIdentifierLength < IdLen)
269       MaxIdentifierLength = IdLen;
270   }
271 
272   fprintf(stderr, "\n*** Identifier Table Stats:\n");
273   fprintf(stderr, "# Identifiers:   %d\n", NumIdentifiers);
274   fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets);
275   fprintf(stderr, "Hash density (#identifiers per bucket): %f\n",
276           NumIdentifiers/(double)NumBuckets);
277   fprintf(stderr, "Ave identifier length: %f\n",
278           (AverageIdentifierSize/(double)NumIdentifiers));
279   fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength);
280 
281   // Compute statistics about the memory allocated for identifiers.
282   HashTable.getAllocator().PrintStats();
283 }
284 
285 //===----------------------------------------------------------------------===//
286 // SelectorTable Implementation
287 //===----------------------------------------------------------------------===//
288 
getHashValue(clang::Selector S)289 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) {
290   return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr());
291 }
292 
293 namespace clang {
294 /// MultiKeywordSelector - One of these variable length records is kept for each
295 /// selector containing more than one keyword. We use a folding set
296 /// to unique aggregate names (keyword selectors in ObjC parlance). Access to
297 /// this class is provided strictly through Selector.
298 class MultiKeywordSelector
299   : public DeclarationNameExtra, public llvm::FoldingSetNode {
MultiKeywordSelector(unsigned nKeys)300   MultiKeywordSelector(unsigned nKeys) {
301     ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
302   }
303 public:
304   // Constructor for keyword selectors.
MultiKeywordSelector(unsigned nKeys,IdentifierInfo ** IIV)305   MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV) {
306     assert((nKeys > 1) && "not a multi-keyword selector");
307     ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys;
308 
309     // Fill in the trailing keyword array.
310     IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1);
311     for (unsigned i = 0; i != nKeys; ++i)
312       KeyInfo[i] = IIV[i];
313   }
314 
315   // getName - Derive the full selector name and return it.
316   std::string getName() const;
317 
getNumArgs() const318   unsigned getNumArgs() const { return ExtraKindOrNumArgs - NUM_EXTRA_KINDS; }
319 
320   typedef IdentifierInfo *const *keyword_iterator;
keyword_begin() const321   keyword_iterator keyword_begin() const {
322     return reinterpret_cast<keyword_iterator>(this+1);
323   }
keyword_end() const324   keyword_iterator keyword_end() const {
325     return keyword_begin()+getNumArgs();
326   }
getIdentifierInfoForSlot(unsigned i) const327   IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const {
328     assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index");
329     return keyword_begin()[i];
330   }
Profile(llvm::FoldingSetNodeID & ID,keyword_iterator ArgTys,unsigned NumArgs)331   static void Profile(llvm::FoldingSetNodeID &ID,
332                       keyword_iterator ArgTys, unsigned NumArgs) {
333     ID.AddInteger(NumArgs);
334     for (unsigned i = 0; i != NumArgs; ++i)
335       ID.AddPointer(ArgTys[i]);
336   }
Profile(llvm::FoldingSetNodeID & ID)337   void Profile(llvm::FoldingSetNodeID &ID) {
338     Profile(ID, keyword_begin(), getNumArgs());
339   }
340 };
341 } // end namespace clang.
342 
getNumArgs() const343 unsigned Selector::getNumArgs() const {
344   unsigned IIF = getIdentifierInfoFlag();
345   if (IIF <= ZeroArg)
346     return 0;
347   if (IIF == OneArg)
348     return 1;
349   // We point to a MultiKeywordSelector.
350   MultiKeywordSelector *SI = getMultiKeywordSelector();
351   return SI->getNumArgs();
352 }
353 
getIdentifierInfoForSlot(unsigned argIndex) const354 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
355   if (getIdentifierInfoFlag() < MultiArg) {
356     assert(argIndex == 0 && "illegal keyword index");
357     return getAsIdentifierInfo();
358   }
359   // We point to a MultiKeywordSelector.
360   MultiKeywordSelector *SI = getMultiKeywordSelector();
361   return SI->getIdentifierInfoForSlot(argIndex);
362 }
363 
getNameForSlot(unsigned int argIndex) const364 StringRef Selector::getNameForSlot(unsigned int argIndex) const {
365   IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
366   return II? II->getName() : StringRef();
367 }
368 
getName() const369 std::string MultiKeywordSelector::getName() const {
370   SmallString<256> Str;
371   llvm::raw_svector_ostream OS(Str);
372   for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) {
373     if (*I)
374       OS << (*I)->getName();
375     OS << ':';
376   }
377 
378   return OS.str();
379 }
380 
getAsString() const381 std::string Selector::getAsString() const {
382   if (InfoPtr == 0)
383     return "<null selector>";
384 
385   if (getIdentifierInfoFlag() < MultiArg) {
386     IdentifierInfo *II = getAsIdentifierInfo();
387 
388     // If the number of arguments is 0 then II is guaranteed to not be null.
389     if (getNumArgs() == 0)
390       return II->getName();
391 
392     if (!II)
393       return ":";
394 
395     return II->getName().str() + ":";
396   }
397 
398   // We have a multiple keyword selector.
399   return getMultiKeywordSelector()->getName();
400 }
401 
402 /// Interpreting the given string using the normal CamelCase
403 /// conventions, determine whether the given string starts with the
404 /// given "word", which is assumed to end in a lowercase letter.
startsWithWord(StringRef name,StringRef word)405 static bool startsWithWord(StringRef name, StringRef word) {
406   if (name.size() < word.size()) return false;
407   return ((name.size() == word.size() ||
408            !islower(name[word.size()]))
409           && name.startswith(word));
410 }
411 
getMethodFamilyImpl(Selector sel)412 ObjCMethodFamily Selector::getMethodFamilyImpl(Selector sel) {
413   IdentifierInfo *first = sel.getIdentifierInfoForSlot(0);
414   if (!first) return OMF_None;
415 
416   StringRef name = first->getName();
417   if (sel.isUnarySelector()) {
418     if (name == "autorelease") return OMF_autorelease;
419     if (name == "dealloc") return OMF_dealloc;
420     if (name == "finalize") return OMF_finalize;
421     if (name == "release") return OMF_release;
422     if (name == "retain") return OMF_retain;
423     if (name == "retainCount") return OMF_retainCount;
424     if (name == "self") return OMF_self;
425   }
426 
427   if (name == "performSelector") return OMF_performSelector;
428 
429   // The other method families may begin with a prefix of underscores.
430   while (!name.empty() && name.front() == '_')
431     name = name.substr(1);
432 
433   if (name.empty()) return OMF_None;
434   switch (name.front()) {
435   case 'a':
436     if (startsWithWord(name, "alloc")) return OMF_alloc;
437     break;
438   case 'c':
439     if (startsWithWord(name, "copy")) return OMF_copy;
440     break;
441   case 'i':
442     if (startsWithWord(name, "init")) return OMF_init;
443     break;
444   case 'm':
445     if (startsWithWord(name, "mutableCopy")) return OMF_mutableCopy;
446     break;
447   case 'n':
448     if (startsWithWord(name, "new")) return OMF_new;
449     break;
450   default:
451     break;
452   }
453 
454   return OMF_None;
455 }
456 
457 namespace {
458   struct SelectorTableImpl {
459     llvm::FoldingSet<MultiKeywordSelector> Table;
460     llvm::BumpPtrAllocator Allocator;
461   };
462 } // end anonymous namespace.
463 
getSelectorTableImpl(void * P)464 static SelectorTableImpl &getSelectorTableImpl(void *P) {
465   return *static_cast<SelectorTableImpl*>(P);
466 }
467 
468 /*static*/ Selector
constructSetterName(IdentifierTable & Idents,SelectorTable & SelTable,const IdentifierInfo * Name)469 SelectorTable::constructSetterName(IdentifierTable &Idents,
470                                    SelectorTable &SelTable,
471                                    const IdentifierInfo *Name) {
472   SmallString<100> SelectorName;
473   SelectorName = "set";
474   SelectorName += Name->getName();
475   SelectorName[3] = toupper(SelectorName[3]);
476   IdentifierInfo *SetterName = &Idents.get(SelectorName);
477   return SelTable.getUnarySelector(SetterName);
478 }
479 
getTotalMemory() const480 size_t SelectorTable::getTotalMemory() const {
481   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
482   return SelTabImpl.Allocator.getTotalMemory();
483 }
484 
getSelector(unsigned nKeys,IdentifierInfo ** IIV)485 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) {
486   if (nKeys < 2)
487     return Selector(IIV[0], nKeys);
488 
489   SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl);
490 
491   // Unique selector, to guarantee there is one per name.
492   llvm::FoldingSetNodeID ID;
493   MultiKeywordSelector::Profile(ID, IIV, nKeys);
494 
495   void *InsertPos = 0;
496   if (MultiKeywordSelector *SI =
497         SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos))
498     return Selector(SI);
499 
500   // MultiKeywordSelector objects are not allocated with new because they have a
501   // variable size array (for parameter types) at the end of them.
502   unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *);
503   MultiKeywordSelector *SI =
504     (MultiKeywordSelector*)SelTabImpl.Allocator.Allocate(Size,
505                                          llvm::alignOf<MultiKeywordSelector>());
506   new (SI) MultiKeywordSelector(nKeys, IIV);
507   SelTabImpl.Table.InsertNode(SI, InsertPos);
508   return Selector(SI);
509 }
510 
SelectorTable()511 SelectorTable::SelectorTable() {
512   Impl = new SelectorTableImpl();
513 }
514 
~SelectorTable()515 SelectorTable::~SelectorTable() {
516   delete &getSelectorTableImpl(Impl);
517 }
518 
getOperatorSpelling(OverloadedOperatorKind Operator)519 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) {
520   switch (Operator) {
521   case OO_None:
522   case NUM_OVERLOADED_OPERATORS:
523     return 0;
524 
525 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \
526   case OO_##Name: return Spelling;
527 #include "clang/Basic/OperatorKinds.def"
528   }
529 
530   llvm_unreachable("Invalid OverloadedOperatorKind!");
531 }
532