1 //===- IdentifierResolver.cpp - Lexical Scope Name lookup -------*- C++ -*-===// 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 IdentifierResolver class, which is used for lexical 11 // scoped lookup, based on declaration names. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Sema/IdentifierResolver.h" 16 #include "clang/AST/Decl.h" 17 #include "clang/Basic/LangOptions.h" 18 #include "clang/Lex/ExternalPreprocessorSource.h" 19 #include "clang/Lex/Preprocessor.h" 20 #include "clang/Sema/Scope.h" 21 22 using namespace clang; 23 24 //===----------------------------------------------------------------------===// 25 // IdDeclInfoMap class 26 //===----------------------------------------------------------------------===// 27 28 /// IdDeclInfoMap - Associates IdDeclInfos with declaration names. 29 /// Allocates 'pools' (vectors of IdDeclInfos) to avoid allocating each 30 /// individual IdDeclInfo to heap. 31 class IdentifierResolver::IdDeclInfoMap { 32 static const unsigned int POOL_SIZE = 512; 33 34 /// We use our own linked-list implementation because it is sadly 35 /// impossible to add something to a pre-C++0x STL container without 36 /// a completely unnecessary copy. 37 struct IdDeclInfoPool { 38 IdDeclInfoPool(IdDeclInfoPool *Next) : Next(Next) {} 39 40 IdDeclInfoPool *Next; 41 IdDeclInfo Pool[POOL_SIZE]; 42 }; 43 44 IdDeclInfoPool *CurPool; 45 unsigned int CurIndex; 46 47 public: 48 IdDeclInfoMap() : CurPool(nullptr), CurIndex(POOL_SIZE) {} 49 50 ~IdDeclInfoMap() { 51 IdDeclInfoPool *Cur = CurPool; 52 while (IdDeclInfoPool *P = Cur) { 53 Cur = Cur->Next; 54 delete P; 55 } 56 } 57 58 /// Returns the IdDeclInfo associated to the DeclarationName. 59 /// It creates a new IdDeclInfo if one was not created before for this id. 60 IdDeclInfo &operator[](DeclarationName Name); 61 }; 62 63 64 //===----------------------------------------------------------------------===// 65 // IdDeclInfo Implementation 66 //===----------------------------------------------------------------------===// 67 68 /// RemoveDecl - Remove the decl from the scope chain. 69 /// The decl must already be part of the decl chain. 70 void IdentifierResolver::IdDeclInfo::RemoveDecl(NamedDecl *D) { 71 for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) { 72 if (D == *(I-1)) { 73 Decls.erase(I-1); 74 return; 75 } 76 } 77 78 llvm_unreachable("Didn't find this decl on its identifier's chain!"); 79 } 80 81 //===----------------------------------------------------------------------===// 82 // IdentifierResolver Implementation 83 //===----------------------------------------------------------------------===// 84 85 IdentifierResolver::IdentifierResolver(Preprocessor &PP) 86 : LangOpt(PP.getLangOpts()), PP(PP), 87 IdDeclInfos(new IdDeclInfoMap) { 88 } 89 90 IdentifierResolver::~IdentifierResolver() { 91 delete IdDeclInfos; 92 } 93 94 /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true 95 /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns 96 /// true if 'D' belongs to the given declaration context. 97 bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S, 98 bool AllowInlineNamespace) const { 99 Ctx = Ctx->getRedeclContext(); 100 101 if (Ctx->isFunctionOrMethod() || (S && S->isFunctionPrototypeScope())) { 102 // Ignore the scopes associated within transparent declaration contexts. 103 while (S->getEntity() && S->getEntity()->isTransparentContext()) 104 S = S->getParent(); 105 106 if (S->isDeclScope(D)) 107 return true; 108 if (LangOpt.CPlusPlus) { 109 // C++ 3.3.2p3: 110 // The name declared in a catch exception-declaration is local to the 111 // handler and shall not be redeclared in the outermost block of the 112 // handler. 113 // C++ 3.3.2p4: 114 // Names declared in the for-init-statement, and in the condition of if, 115 // while, for, and switch statements are local to the if, while, for, or 116 // switch statement (including the controlled statement), and shall not be 117 // redeclared in a subsequent condition of that statement nor in the 118 // outermost block (or, for the if statement, any of the outermost blocks) 119 // of the controlled statement. 120 // 121 assert(S->getParent() && "No TUScope?"); 122 if (S->getParent()->getFlags() & Scope::ControlScope) { 123 S = S->getParent(); 124 if (S->isDeclScope(D)) 125 return true; 126 } 127 if (S->getFlags() & Scope::FnTryCatchScope) 128 return S->getParent()->isDeclScope(D); 129 } 130 return false; 131 } 132 133 // FIXME: If D is a local extern declaration, this check doesn't make sense; 134 // we should be checking its lexical context instead in that case, because 135 // that is its scope. 136 DeclContext *DCtx = D->getDeclContext()->getRedeclContext(); 137 return AllowInlineNamespace ? Ctx->InEnclosingNamespaceSetOf(DCtx) 138 : Ctx->Equals(DCtx); 139 } 140 141 /// AddDecl - Link the decl to its shadowed decl chain. 142 void IdentifierResolver::AddDecl(NamedDecl *D) { 143 DeclarationName Name = D->getDeclName(); 144 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 145 updatingIdentifier(*II); 146 147 void *Ptr = Name.getFETokenInfo<void>(); 148 149 if (!Ptr) { 150 Name.setFETokenInfo(D); 151 return; 152 } 153 154 IdDeclInfo *IDI; 155 156 if (isDeclPtr(Ptr)) { 157 Name.setFETokenInfo(nullptr); 158 IDI = &(*IdDeclInfos)[Name]; 159 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr); 160 IDI->AddDecl(PrevD); 161 } else 162 IDI = toIdDeclInfo(Ptr); 163 164 IDI->AddDecl(D); 165 } 166 167 void IdentifierResolver::InsertDeclAfter(iterator Pos, NamedDecl *D) { 168 DeclarationName Name = D->getDeclName(); 169 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 170 updatingIdentifier(*II); 171 172 void *Ptr = Name.getFETokenInfo<void>(); 173 174 if (!Ptr) { 175 AddDecl(D); 176 return; 177 } 178 179 if (isDeclPtr(Ptr)) { 180 // We only have a single declaration: insert before or after it, 181 // as appropriate. 182 if (Pos == iterator()) { 183 // Add the new declaration before the existing declaration. 184 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr); 185 RemoveDecl(PrevD); 186 AddDecl(D); 187 AddDecl(PrevD); 188 } else { 189 // Add new declaration after the existing declaration. 190 AddDecl(D); 191 } 192 193 return; 194 } 195 196 // General case: insert the declaration at the appropriate point in the 197 // list, which already has at least two elements. 198 IdDeclInfo *IDI = toIdDeclInfo(Ptr); 199 if (Pos.isIterator()) { 200 IDI->InsertDecl(Pos.getIterator() + 1, D); 201 } else 202 IDI->InsertDecl(IDI->decls_begin(), D); 203 } 204 205 /// RemoveDecl - Unlink the decl from its shadowed decl chain. 206 /// The decl must already be part of the decl chain. 207 void IdentifierResolver::RemoveDecl(NamedDecl *D) { 208 assert(D && "null param passed"); 209 DeclarationName Name = D->getDeclName(); 210 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 211 updatingIdentifier(*II); 212 213 void *Ptr = Name.getFETokenInfo<void>(); 214 215 assert(Ptr && "Didn't find this decl on its identifier's chain!"); 216 217 if (isDeclPtr(Ptr)) { 218 assert(D == Ptr && "Didn't find this decl on its identifier's chain!"); 219 Name.setFETokenInfo(nullptr); 220 return; 221 } 222 223 return toIdDeclInfo(Ptr)->RemoveDecl(D); 224 } 225 226 /// begin - Returns an iterator for decls with name 'Name'. 227 IdentifierResolver::iterator 228 IdentifierResolver::begin(DeclarationName Name) { 229 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 230 readingIdentifier(*II); 231 232 void *Ptr = Name.getFETokenInfo<void>(); 233 if (!Ptr) return end(); 234 235 if (isDeclPtr(Ptr)) 236 return iterator(static_cast<NamedDecl*>(Ptr)); 237 238 IdDeclInfo *IDI = toIdDeclInfo(Ptr); 239 240 IdDeclInfo::DeclsTy::iterator I = IDI->decls_end(); 241 if (I != IDI->decls_begin()) 242 return iterator(I-1); 243 // No decls found. 244 return end(); 245 } 246 247 namespace { 248 enum DeclMatchKind { 249 DMK_Different, 250 DMK_Replace, 251 DMK_Ignore 252 }; 253 } 254 255 /// \brief Compare two declarations to see whether they are different or, 256 /// if they are the same, whether the new declaration should replace the 257 /// existing declaration. 258 static DeclMatchKind compareDeclarations(NamedDecl *Existing, NamedDecl *New) { 259 // If the declarations are identical, ignore the new one. 260 if (Existing == New) 261 return DMK_Ignore; 262 263 // If the declarations have different kinds, they're obviously different. 264 if (Existing->getKind() != New->getKind()) 265 return DMK_Different; 266 267 // If the declarations are redeclarations of each other, keep the newest one. 268 if (Existing->getCanonicalDecl() == New->getCanonicalDecl()) { 269 // If we're adding an imported declaration, don't replace another imported 270 // declaration. 271 if (Existing->isFromASTFile() && New->isFromASTFile()) 272 return DMK_Different; 273 274 // If either of these is the most recent declaration, use it. 275 Decl *MostRecent = Existing->getMostRecentDecl(); 276 if (Existing == MostRecent) 277 return DMK_Ignore; 278 279 if (New == MostRecent) 280 return DMK_Replace; 281 282 // If the existing declaration is somewhere in the previous declaration 283 // chain of the new declaration, then prefer the new declaration. 284 for (auto RD : New->redecls()) { 285 if (RD == Existing) 286 return DMK_Replace; 287 288 if (RD->isCanonicalDecl()) 289 break; 290 } 291 292 return DMK_Ignore; 293 } 294 295 return DMK_Different; 296 } 297 298 bool IdentifierResolver::tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name){ 299 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 300 readingIdentifier(*II); 301 302 void *Ptr = Name.getFETokenInfo<void>(); 303 304 if (!Ptr) { 305 Name.setFETokenInfo(D); 306 return true; 307 } 308 309 IdDeclInfo *IDI; 310 311 if (isDeclPtr(Ptr)) { 312 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr); 313 314 switch (compareDeclarations(PrevD, D)) { 315 case DMK_Different: 316 break; 317 318 case DMK_Ignore: 319 return false; 320 321 case DMK_Replace: 322 Name.setFETokenInfo(D); 323 return true; 324 } 325 326 Name.setFETokenInfo(nullptr); 327 IDI = &(*IdDeclInfos)[Name]; 328 329 // If the existing declaration is not visible in translation unit scope, 330 // then add the new top-level declaration first. 331 if (!PrevD->getDeclContext()->getRedeclContext()->isTranslationUnit()) { 332 IDI->AddDecl(D); 333 IDI->AddDecl(PrevD); 334 } else { 335 IDI->AddDecl(PrevD); 336 IDI->AddDecl(D); 337 } 338 return true; 339 } 340 341 IDI = toIdDeclInfo(Ptr); 342 343 // See whether this declaration is identical to any existing declarations. 344 // If not, find the right place to insert it. 345 for (IdDeclInfo::DeclsTy::iterator I = IDI->decls_begin(), 346 IEnd = IDI->decls_end(); 347 I != IEnd; ++I) { 348 349 switch (compareDeclarations(*I, D)) { 350 case DMK_Different: 351 break; 352 353 case DMK_Ignore: 354 return false; 355 356 case DMK_Replace: 357 *I = D; 358 return true; 359 } 360 361 if (!(*I)->getDeclContext()->getRedeclContext()->isTranslationUnit()) { 362 // We've found a declaration that is not visible from the translation 363 // unit (it's in an inner scope). Insert our declaration here. 364 IDI->InsertDecl(I, D); 365 return true; 366 } 367 } 368 369 // Add the declaration to the end. 370 IDI->AddDecl(D); 371 return true; 372 } 373 374 void IdentifierResolver::readingIdentifier(IdentifierInfo &II) { 375 if (II.isOutOfDate()) 376 PP.getExternalSource()->updateOutOfDateIdentifier(II); 377 } 378 379 void IdentifierResolver::updatingIdentifier(IdentifierInfo &II) { 380 if (II.isOutOfDate()) 381 PP.getExternalSource()->updateOutOfDateIdentifier(II); 382 383 if (II.isFromAST()) 384 II.setFETokenInfoChangedSinceDeserialization(); 385 } 386 387 //===----------------------------------------------------------------------===// 388 // IdDeclInfoMap Implementation 389 //===----------------------------------------------------------------------===// 390 391 /// Returns the IdDeclInfo associated to the DeclarationName. 392 /// It creates a new IdDeclInfo if one was not created before for this id. 393 IdentifierResolver::IdDeclInfo & 394 IdentifierResolver::IdDeclInfoMap::operator[](DeclarationName Name) { 395 void *Ptr = Name.getFETokenInfo<void>(); 396 397 if (Ptr) return *toIdDeclInfo(Ptr); 398 399 if (CurIndex == POOL_SIZE) { 400 CurPool = new IdDeclInfoPool(CurPool); 401 CurIndex = 0; 402 } 403 IdDeclInfo *IDI = &CurPool->Pool[CurIndex]; 404 Name.setFETokenInfo(reinterpret_cast<void*>( 405 reinterpret_cast<uintptr_t>(IDI) | 0x1) 406 ); 407 ++CurIndex; 408 return *IDI; 409 } 410 411 void IdentifierResolver::iterator::incrementSlowCase() { 412 NamedDecl *D = **this; 413 void *InfoPtr = D->getDeclName().getFETokenInfo<void>(); 414 assert(!isDeclPtr(InfoPtr) && "Decl with wrong id ?"); 415 IdDeclInfo *Info = toIdDeclInfo(InfoPtr); 416 417 BaseIter I = getIterator(); 418 if (I != Info->decls_begin()) 419 *this = iterator(I-1); 420 else // No more decls. 421 *this = iterator(); 422 } 423