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/StringRef.h" 20 #include "llvm/Support/raw_ostream.h" 21 #include <cstdio> 22 23 using namespace clang; 24 25 //===----------------------------------------------------------------------===// 26 // IdentifierInfo Implementation 27 //===----------------------------------------------------------------------===// 28 29 IdentifierInfo::IdentifierInfo() { 30 TokenID = tok::identifier; 31 ObjCOrBuiltinID = 0; 32 HasMacro = false; 33 IsExtension = false; 34 IsPoisoned = false; 35 IsCPPOperatorKeyword = false; 36 NeedsHandleIdentifier = false; 37 FETokenInfo = 0; 38 Entry = 0; 39 } 40 41 //===----------------------------------------------------------------------===// 42 // IdentifierTable Implementation 43 //===----------------------------------------------------------------------===// 44 45 IdentifierInfoLookup::~IdentifierInfoLookup() {} 46 47 ExternalIdentifierLookup::~ExternalIdentifierLookup() {} 48 49 IdentifierTable::IdentifierTable(const LangOptions &LangOpts, 50 IdentifierInfoLookup* externalLookup) 51 : HashTable(8192), // Start with space for 8K identifiers. 52 ExternalLookup(externalLookup) { 53 54 // Populate the identifier table with info about keywords for the current 55 // language. 56 AddKeywords(LangOpts); 57 } 58 59 //===----------------------------------------------------------------------===// 60 // Language Keyword Implementation 61 //===----------------------------------------------------------------------===// 62 63 // Constants for TokenKinds.def 64 namespace { 65 enum { 66 KEYALL = 1, 67 KEYC99 = 2, 68 KEYCXX = 4, 69 KEYCXX0X = 8, 70 KEYGNU = 16, 71 KEYMS = 32, 72 BOOLSUPPORT = 64, 73 KEYALTIVEC = 128 74 }; 75 } 76 77 /// AddKeyword - This method is used to associate a token ID with specific 78 /// identifiers because they are language keywords. This causes the lexer to 79 /// automatically map matching identifiers to specialized token codes. 80 /// 81 /// The C90/C99/CPP/CPP0x flags are set to 2 if the token should be 82 /// enabled in the specified langauge, set to 1 if it is an extension 83 /// in the specified language, and set to 0 if disabled in the 84 /// specified language. 85 static void AddKeyword(llvm::StringRef Keyword, 86 tok::TokenKind TokenCode, unsigned Flags, 87 const LangOptions &LangOpts, IdentifierTable &Table) { 88 unsigned AddResult = 0; 89 if (Flags & KEYALL) AddResult = 2; 90 else if (LangOpts.CPlusPlus && (Flags & KEYCXX)) AddResult = 2; 91 else if (LangOpts.CPlusPlus0x && (Flags & KEYCXX0X)) AddResult = 2; 92 else if (LangOpts.C99 && (Flags & KEYC99)) AddResult = 2; 93 else if (LangOpts.GNUKeywords && (Flags & KEYGNU)) AddResult = 1; 94 else if (LangOpts.Microsoft && (Flags & KEYMS)) AddResult = 1; 95 else if (LangOpts.Bool && (Flags & BOOLSUPPORT)) AddResult = 2; 96 else if (LangOpts.AltiVec && (Flags & KEYALTIVEC)) AddResult = 2; 97 98 // Don't add this keyword if disabled in this language. 99 if (AddResult == 0) return; 100 101 IdentifierInfo &Info = Table.get(Keyword); 102 Info.setTokenID(TokenCode); 103 Info.setIsExtensionToken(AddResult == 1); 104 } 105 106 /// AddCXXOperatorKeyword - Register a C++ operator keyword alternative 107 /// representations. 108 static void AddCXXOperatorKeyword(llvm::StringRef Keyword, 109 tok::TokenKind TokenCode, 110 IdentifierTable &Table) { 111 IdentifierInfo &Info = Table.get(Keyword); 112 Info.setTokenID(TokenCode); 113 Info.setIsCPlusPlusOperatorKeyword(); 114 } 115 116 /// AddObjCKeyword - Register an Objective-C @keyword like "class" "selector" or 117 /// "property". 118 static void AddObjCKeyword(llvm::StringRef Name, 119 tok::ObjCKeywordKind ObjCID, 120 IdentifierTable &Table) { 121 Table.get(Name).setObjCKeywordID(ObjCID); 122 } 123 124 /// AddKeywords - Add all keywords to the symbol table. 125 /// 126 void IdentifierTable::AddKeywords(const LangOptions &LangOpts) { 127 // Add keywords and tokens for the current language. 128 #define KEYWORD(NAME, FLAGS) \ 129 AddKeyword(llvm::StringRef(#NAME), tok::kw_ ## NAME, \ 130 FLAGS, LangOpts, *this); 131 #define ALIAS(NAME, TOK, FLAGS) \ 132 AddKeyword(llvm::StringRef(NAME), tok::kw_ ## TOK, \ 133 FLAGS, LangOpts, *this); 134 #define CXX_KEYWORD_OPERATOR(NAME, ALIAS) \ 135 if (LangOpts.CXXOperatorNames) \ 136 AddCXXOperatorKeyword(llvm::StringRef(#NAME), tok::ALIAS, *this); 137 #define OBJC1_AT_KEYWORD(NAME) \ 138 if (LangOpts.ObjC1) \ 139 AddObjCKeyword(llvm::StringRef(#NAME), tok::objc_##NAME, *this); 140 #define OBJC2_AT_KEYWORD(NAME) \ 141 if (LangOpts.ObjC2) \ 142 AddObjCKeyword(llvm::StringRef(#NAME), tok::objc_##NAME, *this); 143 #include "clang/Basic/TokenKinds.def" 144 } 145 146 tok::PPKeywordKind IdentifierInfo::getPPKeywordID() const { 147 // We use a perfect hash function here involving the length of the keyword, 148 // the first and third character. For preprocessor ID's there are no 149 // collisions (if there were, the switch below would complain about duplicate 150 // case values). Note that this depends on 'if' being null terminated. 151 152 #define HASH(LEN, FIRST, THIRD) \ 153 (LEN << 5) + (((FIRST-'a') + (THIRD-'a')) & 31) 154 #define CASE(LEN, FIRST, THIRD, NAME) \ 155 case HASH(LEN, FIRST, THIRD): \ 156 return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME 157 158 unsigned Len = getLength(); 159 if (Len < 2) return tok::pp_not_keyword; 160 const char *Name = getNameStart(); 161 switch (HASH(Len, Name[0], Name[2])) { 162 default: return tok::pp_not_keyword; 163 CASE( 2, 'i', '\0', if); 164 CASE( 4, 'e', 'i', elif); 165 CASE( 4, 'e', 's', else); 166 CASE( 4, 'l', 'n', line); 167 CASE( 4, 's', 'c', sccs); 168 CASE( 5, 'e', 'd', endif); 169 CASE( 5, 'e', 'r', error); 170 CASE( 5, 'i', 'e', ident); 171 CASE( 5, 'i', 'd', ifdef); 172 CASE( 5, 'u', 'd', undef); 173 174 CASE( 6, 'a', 's', assert); 175 CASE( 6, 'd', 'f', define); 176 CASE( 6, 'i', 'n', ifndef); 177 CASE( 6, 'i', 'p', import); 178 CASE( 6, 'p', 'a', pragma); 179 180 CASE( 7, 'd', 'f', defined); 181 CASE( 7, 'i', 'c', include); 182 CASE( 7, 'w', 'r', warning); 183 184 CASE( 8, 'u', 'a', unassert); 185 CASE(12, 'i', 'c', include_next); 186 187 CASE(16, '_', 'i', __include_macros); 188 #undef CASE 189 #undef HASH 190 } 191 } 192 193 //===----------------------------------------------------------------------===// 194 // Stats Implementation 195 //===----------------------------------------------------------------------===// 196 197 /// PrintStats - Print statistics about how well the identifier table is doing 198 /// at hashing identifiers. 199 void IdentifierTable::PrintStats() const { 200 unsigned NumBuckets = HashTable.getNumBuckets(); 201 unsigned NumIdentifiers = HashTable.getNumItems(); 202 unsigned NumEmptyBuckets = NumBuckets-NumIdentifiers; 203 unsigned AverageIdentifierSize = 0; 204 unsigned MaxIdentifierLength = 0; 205 206 // TODO: Figure out maximum times an identifier had to probe for -stats. 207 for (llvm::StringMap<IdentifierInfo*, llvm::BumpPtrAllocator>::const_iterator 208 I = HashTable.begin(), E = HashTable.end(); I != E; ++I) { 209 unsigned IdLen = I->getKeyLength(); 210 AverageIdentifierSize += IdLen; 211 if (MaxIdentifierLength < IdLen) 212 MaxIdentifierLength = IdLen; 213 } 214 215 fprintf(stderr, "\n*** Identifier Table Stats:\n"); 216 fprintf(stderr, "# Identifiers: %d\n", NumIdentifiers); 217 fprintf(stderr, "# Empty Buckets: %d\n", NumEmptyBuckets); 218 fprintf(stderr, "Hash density (#identifiers per bucket): %f\n", 219 NumIdentifiers/(double)NumBuckets); 220 fprintf(stderr, "Ave identifier length: %f\n", 221 (AverageIdentifierSize/(double)NumIdentifiers)); 222 fprintf(stderr, "Max identifier length: %d\n", MaxIdentifierLength); 223 224 // Compute statistics about the memory allocated for identifiers. 225 HashTable.getAllocator().PrintStats(); 226 } 227 228 //===----------------------------------------------------------------------===// 229 // SelectorTable Implementation 230 //===----------------------------------------------------------------------===// 231 232 unsigned llvm::DenseMapInfo<clang::Selector>::getHashValue(clang::Selector S) { 233 return DenseMapInfo<void*>::getHashValue(S.getAsOpaquePtr()); 234 } 235 236 namespace clang { 237 /// MultiKeywordSelector - One of these variable length records is kept for each 238 /// selector containing more than one keyword. We use a folding set 239 /// to unique aggregate names (keyword selectors in ObjC parlance). Access to 240 /// this class is provided strictly through Selector. 241 class MultiKeywordSelector 242 : public DeclarationNameExtra, public llvm::FoldingSetNode { 243 MultiKeywordSelector(unsigned nKeys) { 244 ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys; 245 } 246 public: 247 // Constructor for keyword selectors. 248 MultiKeywordSelector(unsigned nKeys, IdentifierInfo **IIV) { 249 assert((nKeys > 1) && "not a multi-keyword selector"); 250 ExtraKindOrNumArgs = NUM_EXTRA_KINDS + nKeys; 251 252 // Fill in the trailing keyword array. 253 IdentifierInfo **KeyInfo = reinterpret_cast<IdentifierInfo **>(this+1); 254 for (unsigned i = 0; i != nKeys; ++i) 255 KeyInfo[i] = IIV[i]; 256 } 257 258 // getName - Derive the full selector name and return it. 259 std::string getName() const; 260 261 unsigned getNumArgs() const { return ExtraKindOrNumArgs - NUM_EXTRA_KINDS; } 262 263 typedef IdentifierInfo *const *keyword_iterator; 264 keyword_iterator keyword_begin() const { 265 return reinterpret_cast<keyword_iterator>(this+1); 266 } 267 keyword_iterator keyword_end() const { 268 return keyword_begin()+getNumArgs(); 269 } 270 IdentifierInfo *getIdentifierInfoForSlot(unsigned i) const { 271 assert(i < getNumArgs() && "getIdentifierInfoForSlot(): illegal index"); 272 return keyword_begin()[i]; 273 } 274 static void Profile(llvm::FoldingSetNodeID &ID, 275 keyword_iterator ArgTys, unsigned NumArgs) { 276 ID.AddInteger(NumArgs); 277 for (unsigned i = 0; i != NumArgs; ++i) 278 ID.AddPointer(ArgTys[i]); 279 } 280 void Profile(llvm::FoldingSetNodeID &ID) { 281 Profile(ID, keyword_begin(), getNumArgs()); 282 } 283 }; 284 } // end namespace clang. 285 286 unsigned Selector::getNumArgs() const { 287 unsigned IIF = getIdentifierInfoFlag(); 288 if (IIF == ZeroArg) 289 return 0; 290 if (IIF == OneArg) 291 return 1; 292 // We point to a MultiKeywordSelector (pointer doesn't contain any flags). 293 MultiKeywordSelector *SI = reinterpret_cast<MultiKeywordSelector *>(InfoPtr); 294 return SI->getNumArgs(); 295 } 296 297 IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const { 298 if (getIdentifierInfoFlag()) { 299 assert(argIndex == 0 && "illegal keyword index"); 300 return getAsIdentifierInfo(); 301 } 302 // We point to a MultiKeywordSelector (pointer doesn't contain any flags). 303 MultiKeywordSelector *SI = reinterpret_cast<MultiKeywordSelector *>(InfoPtr); 304 return SI->getIdentifierInfoForSlot(argIndex); 305 } 306 307 std::string MultiKeywordSelector::getName() const { 308 llvm::SmallString<256> Str; 309 llvm::raw_svector_ostream OS(Str); 310 for (keyword_iterator I = keyword_begin(), E = keyword_end(); I != E; ++I) { 311 if (*I) 312 OS << (*I)->getName(); 313 OS << ':'; 314 } 315 316 return OS.str(); 317 } 318 319 std::string Selector::getAsString() const { 320 if (InfoPtr == 0) 321 return "<null selector>"; 322 323 if (InfoPtr & ArgFlags) { 324 IdentifierInfo *II = getAsIdentifierInfo(); 325 326 // If the number of arguments is 0 then II is guaranteed to not be null. 327 if (getNumArgs() == 0) 328 return II->getName(); 329 330 if (!II) 331 return ":"; 332 333 return II->getName().str() + ":"; 334 } 335 336 // We have a multiple keyword selector (no embedded flags). 337 return reinterpret_cast<MultiKeywordSelector *>(InfoPtr)->getName(); 338 } 339 340 341 namespace { 342 struct SelectorTableImpl { 343 llvm::FoldingSet<MultiKeywordSelector> Table; 344 llvm::BumpPtrAllocator Allocator; 345 }; 346 } // end anonymous namespace. 347 348 static SelectorTableImpl &getSelectorTableImpl(void *P) { 349 return *static_cast<SelectorTableImpl*>(P); 350 } 351 352 353 Selector SelectorTable::getSelector(unsigned nKeys, IdentifierInfo **IIV) { 354 if (nKeys < 2) 355 return Selector(IIV[0], nKeys); 356 357 SelectorTableImpl &SelTabImpl = getSelectorTableImpl(Impl); 358 359 // Unique selector, to guarantee there is one per name. 360 llvm::FoldingSetNodeID ID; 361 MultiKeywordSelector::Profile(ID, IIV, nKeys); 362 363 void *InsertPos = 0; 364 if (MultiKeywordSelector *SI = 365 SelTabImpl.Table.FindNodeOrInsertPos(ID, InsertPos)) 366 return Selector(SI); 367 368 // MultiKeywordSelector objects are not allocated with new because they have a 369 // variable size array (for parameter types) at the end of them. 370 unsigned Size = sizeof(MultiKeywordSelector) + nKeys*sizeof(IdentifierInfo *); 371 MultiKeywordSelector *SI = 372 (MultiKeywordSelector*)SelTabImpl.Allocator.Allocate(Size, 373 llvm::alignof<MultiKeywordSelector>()); 374 new (SI) MultiKeywordSelector(nKeys, IIV); 375 SelTabImpl.Table.InsertNode(SI, InsertPos); 376 return Selector(SI); 377 } 378 379 SelectorTable::SelectorTable() { 380 Impl = new SelectorTableImpl(); 381 } 382 383 SelectorTable::~SelectorTable() { 384 delete &getSelectorTableImpl(Impl); 385 } 386 387 const char *clang::getOperatorSpelling(OverloadedOperatorKind Operator) { 388 switch (Operator) { 389 case OO_None: 390 case NUM_OVERLOADED_OPERATORS: 391 return 0; 392 393 #define OVERLOADED_OPERATOR(Name,Spelling,Token,Unary,Binary,MemberOnly) \ 394 case OO_##Name: return Spelling; 395 #include "clang/Basic/OperatorKinds.def" 396 } 397 398 return 0; 399 } 400 401