IdentifierResolver.cpp revision 263508
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 22using 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. 31class 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 47public: 48 IdDeclInfoMap() : CurPool(0), 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. 70void 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 85IdentifierResolver::IdentifierResolver(Preprocessor &PP) 86 : LangOpt(PP.getLangOpts()), PP(PP), 87 IdDeclInfos(new IdDeclInfoMap) { 88} 89 90IdentifierResolver::~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. 97bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S, 98 bool ExplicitInstantiationOrSpecialization) const { 99 Ctx = Ctx->getRedeclContext(); 100 101 if (Ctx->isFunctionOrMethod() || 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 DeclContext *DCtx = D->getDeclContext()->getRedeclContext(); 134 return ExplicitInstantiationOrSpecialization 135 ? Ctx->InEnclosingNamespaceSetOf(DCtx) 136 : Ctx->Equals(DCtx); 137} 138 139/// AddDecl - Link the decl to its shadowed decl chain. 140void IdentifierResolver::AddDecl(NamedDecl *D) { 141 DeclarationName Name = D->getDeclName(); 142 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 143 updatingIdentifier(*II); 144 145 void *Ptr = Name.getFETokenInfo<void>(); 146 147 if (!Ptr) { 148 Name.setFETokenInfo(D); 149 return; 150 } 151 152 IdDeclInfo *IDI; 153 154 if (isDeclPtr(Ptr)) { 155 Name.setFETokenInfo(NULL); 156 IDI = &(*IdDeclInfos)[Name]; 157 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr); 158 IDI->AddDecl(PrevD); 159 } else 160 IDI = toIdDeclInfo(Ptr); 161 162 IDI->AddDecl(D); 163} 164 165void IdentifierResolver::InsertDeclAfter(iterator Pos, NamedDecl *D) { 166 DeclarationName Name = D->getDeclName(); 167 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 168 updatingIdentifier(*II); 169 170 void *Ptr = Name.getFETokenInfo<void>(); 171 172 if (!Ptr) { 173 AddDecl(D); 174 return; 175 } 176 177 if (isDeclPtr(Ptr)) { 178 // We only have a single declaration: insert before or after it, 179 // as appropriate. 180 if (Pos == iterator()) { 181 // Add the new declaration before the existing declaration. 182 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr); 183 RemoveDecl(PrevD); 184 AddDecl(D); 185 AddDecl(PrevD); 186 } else { 187 // Add new declaration after the existing declaration. 188 AddDecl(D); 189 } 190 191 return; 192 } 193 194 // General case: insert the declaration at the appropriate point in the 195 // list, which already has at least two elements. 196 IdDeclInfo *IDI = toIdDeclInfo(Ptr); 197 if (Pos.isIterator()) { 198 IDI->InsertDecl(Pos.getIterator() + 1, D); 199 } else 200 IDI->InsertDecl(IDI->decls_begin(), D); 201} 202 203/// RemoveDecl - Unlink the decl from its shadowed decl chain. 204/// The decl must already be part of the decl chain. 205void IdentifierResolver::RemoveDecl(NamedDecl *D) { 206 assert(D && "null param passed"); 207 DeclarationName Name = D->getDeclName(); 208 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 209 updatingIdentifier(*II); 210 211 void *Ptr = Name.getFETokenInfo<void>(); 212 213 assert(Ptr && "Didn't find this decl on its identifier's chain!"); 214 215 if (isDeclPtr(Ptr)) { 216 assert(D == Ptr && "Didn't find this decl on its identifier's chain!"); 217 Name.setFETokenInfo(NULL); 218 return; 219 } 220 221 return toIdDeclInfo(Ptr)->RemoveDecl(D); 222} 223 224/// begin - Returns an iterator for decls with name 'Name'. 225IdentifierResolver::iterator 226IdentifierResolver::begin(DeclarationName Name) { 227 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 228 readingIdentifier(*II); 229 230 void *Ptr = Name.getFETokenInfo<void>(); 231 if (!Ptr) return end(); 232 233 if (isDeclPtr(Ptr)) 234 return iterator(static_cast<NamedDecl*>(Ptr)); 235 236 IdDeclInfo *IDI = toIdDeclInfo(Ptr); 237 238 IdDeclInfo::DeclsTy::iterator I = IDI->decls_end(); 239 if (I != IDI->decls_begin()) 240 return iterator(I-1); 241 // No decls found. 242 return end(); 243} 244 245namespace { 246 enum DeclMatchKind { 247 DMK_Different, 248 DMK_Replace, 249 DMK_Ignore 250 }; 251} 252 253/// \brief Compare two declarations to see whether they are different or, 254/// if they are the same, whether the new declaration should replace the 255/// existing declaration. 256static DeclMatchKind compareDeclarations(NamedDecl *Existing, NamedDecl *New) { 257 // If the declarations are identical, ignore the new one. 258 if (Existing == New) 259 return DMK_Ignore; 260 261 // If the declarations have different kinds, they're obviously different. 262 if (Existing->getKind() != New->getKind()) 263 return DMK_Different; 264 265 // If the declarations are redeclarations of each other, keep the newest one. 266 if (Existing->getCanonicalDecl() == New->getCanonicalDecl()) { 267 // If either of these is the most recent declaration, use it. 268 Decl *MostRecent = Existing->getMostRecentDecl(); 269 if (Existing == MostRecent) 270 return DMK_Ignore; 271 272 if (New == MostRecent) 273 return DMK_Replace; 274 275 // If the existing declaration is somewhere in the previous declaration 276 // chain of the new declaration, then prefer the new declaration. 277 for (Decl::redecl_iterator RD = New->redecls_begin(), 278 RDEnd = New->redecls_end(); 279 RD != RDEnd; ++RD) { 280 if (*RD == Existing) 281 return DMK_Replace; 282 283 if (RD->isCanonicalDecl()) 284 break; 285 } 286 287 return DMK_Ignore; 288 } 289 290 return DMK_Different; 291} 292 293bool IdentifierResolver::tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name){ 294 if (IdentifierInfo *II = Name.getAsIdentifierInfo()) 295 readingIdentifier(*II); 296 297 void *Ptr = Name.getFETokenInfo<void>(); 298 299 if (!Ptr) { 300 Name.setFETokenInfo(D); 301 return true; 302 } 303 304 IdDeclInfo *IDI; 305 306 if (isDeclPtr(Ptr)) { 307 NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr); 308 309 switch (compareDeclarations(PrevD, D)) { 310 case DMK_Different: 311 break; 312 313 case DMK_Ignore: 314 return false; 315 316 case DMK_Replace: 317 Name.setFETokenInfo(D); 318 return true; 319 } 320 321 Name.setFETokenInfo(NULL); 322 IDI = &(*IdDeclInfos)[Name]; 323 324 // If the existing declaration is not visible in translation unit scope, 325 // then add the new top-level declaration first. 326 if (!PrevD->getDeclContext()->getRedeclContext()->isTranslationUnit()) { 327 IDI->AddDecl(D); 328 IDI->AddDecl(PrevD); 329 } else { 330 IDI->AddDecl(PrevD); 331 IDI->AddDecl(D); 332 } 333 return true; 334 } 335 336 IDI = toIdDeclInfo(Ptr); 337 338 // See whether this declaration is identical to any existing declarations. 339 // If not, find the right place to insert it. 340 for (IdDeclInfo::DeclsTy::iterator I = IDI->decls_begin(), 341 IEnd = IDI->decls_end(); 342 I != IEnd; ++I) { 343 344 switch (compareDeclarations(*I, D)) { 345 case DMK_Different: 346 break; 347 348 case DMK_Ignore: 349 return false; 350 351 case DMK_Replace: 352 *I = D; 353 return true; 354 } 355 356 if (!(*I)->getDeclContext()->getRedeclContext()->isTranslationUnit()) { 357 // We've found a declaration that is not visible from the translation 358 // unit (it's in an inner scope). Insert our declaration here. 359 IDI->InsertDecl(I, D); 360 return true; 361 } 362 } 363 364 // Add the declaration to the end. 365 IDI->AddDecl(D); 366 return true; 367} 368 369void IdentifierResolver::readingIdentifier(IdentifierInfo &II) { 370 if (II.isOutOfDate()) 371 PP.getExternalSource()->updateOutOfDateIdentifier(II); 372} 373 374void IdentifierResolver::updatingIdentifier(IdentifierInfo &II) { 375 if (II.isOutOfDate()) 376 PP.getExternalSource()->updateOutOfDateIdentifier(II); 377 378 if (II.isFromAST()) 379 II.setChangedSinceDeserialization(); 380} 381 382//===----------------------------------------------------------------------===// 383// IdDeclInfoMap Implementation 384//===----------------------------------------------------------------------===// 385 386/// Returns the IdDeclInfo associated to the DeclarationName. 387/// It creates a new IdDeclInfo if one was not created before for this id. 388IdentifierResolver::IdDeclInfo & 389IdentifierResolver::IdDeclInfoMap::operator[](DeclarationName Name) { 390 void *Ptr = Name.getFETokenInfo<void>(); 391 392 if (Ptr) return *toIdDeclInfo(Ptr); 393 394 if (CurIndex == POOL_SIZE) { 395 CurPool = new IdDeclInfoPool(CurPool); 396 CurIndex = 0; 397 } 398 IdDeclInfo *IDI = &CurPool->Pool[CurIndex]; 399 Name.setFETokenInfo(reinterpret_cast<void*>( 400 reinterpret_cast<uintptr_t>(IDI) | 0x1) 401 ); 402 ++CurIndex; 403 return *IDI; 404} 405 406void IdentifierResolver::iterator::incrementSlowCase() { 407 NamedDecl *D = **this; 408 void *InfoPtr = D->getDeclName().getFETokenInfo<void>(); 409 assert(!isDeclPtr(InfoPtr) && "Decl with wrong id ?"); 410 IdDeclInfo *Info = toIdDeclInfo(InfoPtr); 411 412 BaseIter I = getIterator(); 413 if (I != Info->decls_begin()) 414 *this = iterator(I-1); 415 else // No more decls. 416 *this = iterator(); 417} 418