1 //===--- Sema.cpp - AST Builder and Semantic Analysis Implementation ------===// 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 actions class which performs semantic analysis and 11 // builds an AST out of a parse stream. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Sema/SemaInternal.h" 16 #include "clang/Sema/DelayedDiagnostic.h" 17 #include "TargetAttributesSema.h" 18 #include "llvm/ADT/DenseMap.h" 19 #include "llvm/ADT/SmallSet.h" 20 #include "llvm/ADT/APFloat.h" 21 #include "clang/Sema/CXXFieldCollector.h" 22 #include "clang/Sema/TemplateDeduction.h" 23 #include "clang/Sema/ExternalSemaSource.h" 24 #include "clang/Sema/ObjCMethodList.h" 25 #include "clang/Sema/PrettyDeclStackTrace.h" 26 #include "clang/Sema/Scope.h" 27 #include "clang/Sema/ScopeInfo.h" 28 #include "clang/Sema/SemaConsumer.h" 29 #include "clang/AST/ASTContext.h" 30 #include "clang/AST/ASTDiagnostic.h" 31 #include "clang/AST/DeclCXX.h" 32 #include "clang/AST/DeclObjC.h" 33 #include "clang/AST/Expr.h" 34 #include "clang/AST/ExprCXX.h" 35 #include "clang/AST/StmtCXX.h" 36 #include "clang/Lex/Preprocessor.h" 37 #include "clang/Basic/FileManager.h" 38 #include "clang/Basic/PartialDiagnostic.h" 39 #include "clang/Basic/TargetInfo.h" 40 using namespace clang; 41 using namespace sema; 42 43 FunctionScopeInfo::~FunctionScopeInfo() { } 44 45 void FunctionScopeInfo::Clear() { 46 HasBranchProtectedScope = false; 47 HasBranchIntoScope = false; 48 HasIndirectGoto = false; 49 50 SwitchStack.clear(); 51 Returns.clear(); 52 ErrorTrap.reset(); 53 PossiblyUnreachableDiags.clear(); 54 } 55 56 BlockScopeInfo::~BlockScopeInfo() { } 57 58 PrintingPolicy Sema::getPrintingPolicy() const { 59 PrintingPolicy Policy = Context.getPrintingPolicy(); 60 Policy.Bool = getLangOptions().Bool; 61 if (!Policy.Bool) { 62 if (MacroInfo *BoolMacro = PP.getMacroInfo(&Context.Idents.get("bool"))) { 63 Policy.Bool = BoolMacro->isObjectLike() && 64 BoolMacro->getNumTokens() == 1 && 65 BoolMacro->getReplacementToken(0).is(tok::kw__Bool); 66 } 67 } 68 69 return Policy; 70 } 71 72 void Sema::ActOnTranslationUnitScope(Scope *S) { 73 TUScope = S; 74 PushDeclContext(S, Context.getTranslationUnitDecl()); 75 76 VAListTagName = PP.getIdentifierInfo("__va_list_tag"); 77 78 if (PP.getLangOptions().ObjC1) { 79 // Synthesize "@class Protocol; 80 if (Context.getObjCProtoType().isNull()) { 81 ObjCInterfaceDecl *ProtocolDecl = 82 ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(), 83 &Context.Idents.get("Protocol"), 84 SourceLocation(), true); 85 Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl)); 86 PushOnScopeChains(ProtocolDecl, TUScope, false); 87 } 88 } 89 } 90 91 Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer, 92 TranslationUnitKind TUKind, 93 CodeCompleteConsumer *CodeCompleter) 94 : TheTargetAttributesSema(0), FPFeatures(pp.getLangOptions()), 95 LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer), 96 Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()), 97 CollectStats(false), ExternalSource(0), CodeCompleter(CodeCompleter), 98 CurContext(0), OriginalLexicalContext(0), 99 PackContext(0), MSStructPragmaOn(false), VisContext(0), 100 ExprNeedsCleanups(0), LateTemplateParser(0), OpaqueParser(0), 101 IdResolver(pp.getLangOptions()), CXXTypeInfoDecl(0), MSVCGuidDecl(0), 102 GlobalNewDeleteDeclared(false), 103 ObjCShouldCallSuperDealloc(false), 104 ObjCShouldCallSuperFinalize(false), 105 TUKind(TUKind), 106 NumSFINAEErrors(0), SuppressAccessChecking(false), 107 AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false), 108 NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1), 109 CurrentInstantiationScope(0), TyposCorrected(0), 110 AnalysisWarnings(*this) 111 { 112 TUScope = 0; 113 LoadedExternalKnownNamespaces = false; 114 115 if (getLangOptions().CPlusPlus) 116 FieldCollector.reset(new CXXFieldCollector()); 117 118 // Tell diagnostics how to render things from the AST library. 119 PP.getDiagnostics().SetArgToStringFn(&FormatASTNodeDiagnosticArgument, 120 &Context); 121 122 ExprEvalContexts.push_back( 123 ExpressionEvaluationContextRecord(PotentiallyEvaluated, 0, false)); 124 125 FunctionScopes.push_back(new FunctionScopeInfo(Diags)); 126 } 127 128 void Sema::Initialize() { 129 // Tell the AST consumer about this Sema object. 130 Consumer.Initialize(Context); 131 132 // FIXME: Isn't this redundant with the initialization above? 133 if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer)) 134 SC->InitializeSema(*this); 135 136 // Tell the external Sema source about this Sema object. 137 if (ExternalSemaSource *ExternalSema 138 = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource())) 139 ExternalSema->InitializeSema(*this); 140 141 // Initialize predefined 128-bit integer types, if needed. 142 if (PP.getTargetInfo().getPointerWidth(0) >= 64) { 143 // If either of the 128-bit integer types are unavailable to name lookup, 144 // define them now. 145 DeclarationName Int128 = &Context.Idents.get("__int128_t"); 146 if (IdentifierResolver::begin(Int128) == IdentifierResolver::end()) 147 PushOnScopeChains(Context.getInt128Decl(), TUScope); 148 149 DeclarationName UInt128 = &Context.Idents.get("__uint128_t"); 150 if (IdentifierResolver::begin(UInt128) == IdentifierResolver::end()) 151 PushOnScopeChains(Context.getUInt128Decl(), TUScope); 152 } 153 154 155 // Initialize predefined Objective-C types: 156 if (PP.getLangOptions().ObjC1) { 157 // If 'SEL' does not yet refer to any declarations, make it refer to the 158 // predefined 'SEL'. 159 DeclarationName SEL = &Context.Idents.get("SEL"); 160 if (IdentifierResolver::begin(SEL) == IdentifierResolver::end()) 161 PushOnScopeChains(Context.getObjCSelDecl(), TUScope); 162 163 // If 'id' does not yet refer to any declarations, make it refer to the 164 // predefined 'id'. 165 DeclarationName Id = &Context.Idents.get("id"); 166 if (IdentifierResolver::begin(Id) == IdentifierResolver::end()) 167 PushOnScopeChains(Context.getObjCIdDecl(), TUScope); 168 169 // Create the built-in typedef for 'Class'. 170 DeclarationName Class = &Context.Idents.get("Class"); 171 if (IdentifierResolver::begin(Class) == IdentifierResolver::end()) 172 PushOnScopeChains(Context.getObjCClassDecl(), TUScope); 173 } 174 } 175 176 Sema::~Sema() { 177 if (PackContext) FreePackedContext(); 178 if (VisContext) FreeVisContext(); 179 delete TheTargetAttributesSema; 180 MSStructPragmaOn = false; 181 // Kill all the active scopes. 182 for (unsigned I = 1, E = FunctionScopes.size(); I != E; ++I) 183 delete FunctionScopes[I]; 184 if (FunctionScopes.size() == 1) 185 delete FunctionScopes[0]; 186 187 // Tell the SemaConsumer to forget about us; we're going out of scope. 188 if (SemaConsumer *SC = dyn_cast<SemaConsumer>(&Consumer)) 189 SC->ForgetSema(); 190 191 // Detach from the external Sema source. 192 if (ExternalSemaSource *ExternalSema 193 = dyn_cast_or_null<ExternalSemaSource>(Context.getExternalSource())) 194 ExternalSema->ForgetSema(); 195 } 196 197 198 /// makeUnavailableInSystemHeader - There is an error in the current 199 /// context. If we're still in a system header, and we can plausibly 200 /// make the relevant declaration unavailable instead of erroring, do 201 /// so and return true. 202 bool Sema::makeUnavailableInSystemHeader(SourceLocation loc, 203 StringRef msg) { 204 // If we're not in a function, it's an error. 205 FunctionDecl *fn = dyn_cast<FunctionDecl>(CurContext); 206 if (!fn) return false; 207 208 // If we're in template instantiation, it's an error. 209 if (!ActiveTemplateInstantiations.empty()) 210 return false; 211 212 // If that function's not in a system header, it's an error. 213 if (!Context.getSourceManager().isInSystemHeader(loc)) 214 return false; 215 216 // If the function is already unavailable, it's not an error. 217 if (fn->hasAttr<UnavailableAttr>()) return true; 218 219 fn->addAttr(new (Context) UnavailableAttr(loc, Context, msg)); 220 return true; 221 } 222 223 ASTMutationListener *Sema::getASTMutationListener() const { 224 return getASTConsumer().GetASTMutationListener(); 225 } 226 227 /// \brief Print out statistics about the semantic analysis. 228 void Sema::PrintStats() const { 229 llvm::errs() << "\n*** Semantic Analysis Stats:\n"; 230 llvm::errs() << NumSFINAEErrors << " SFINAE diagnostics trapped.\n"; 231 232 BumpAlloc.PrintStats(); 233 AnalysisWarnings.PrintStats(); 234 } 235 236 /// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast. 237 /// If there is already an implicit cast, merge into the existing one. 238 /// The result is of the given category. 239 ExprResult Sema::ImpCastExprToType(Expr *E, QualType Ty, 240 CastKind Kind, ExprValueKind VK, 241 const CXXCastPath *BasePath, 242 CheckedConversionKind CCK) { 243 QualType ExprTy = Context.getCanonicalType(E->getType()); 244 QualType TypeTy = Context.getCanonicalType(Ty); 245 246 if (ExprTy == TypeTy) 247 return Owned(E); 248 249 if (getLangOptions().ObjCAutoRefCount) 250 CheckObjCARCConversion(SourceRange(), Ty, E, CCK); 251 252 // If this is a derived-to-base cast to a through a virtual base, we 253 // need a vtable. 254 if (Kind == CK_DerivedToBase && 255 BasePathInvolvesVirtualBase(*BasePath)) { 256 QualType T = E->getType(); 257 if (const PointerType *Pointer = T->getAs<PointerType>()) 258 T = Pointer->getPointeeType(); 259 if (const RecordType *RecordTy = T->getAs<RecordType>()) 260 MarkVTableUsed(E->getLocStart(), 261 cast<CXXRecordDecl>(RecordTy->getDecl())); 262 } 263 264 if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(E)) { 265 if (ImpCast->getCastKind() == Kind && (!BasePath || BasePath->empty())) { 266 ImpCast->setType(Ty); 267 ImpCast->setValueKind(VK); 268 return Owned(E); 269 } 270 } 271 272 return Owned(ImplicitCastExpr::Create(Context, Ty, Kind, E, BasePath, VK)); 273 } 274 275 /// ScalarTypeToBooleanCastKind - Returns the cast kind corresponding 276 /// to the conversion from scalar type ScalarTy to the Boolean type. 277 CastKind Sema::ScalarTypeToBooleanCastKind(QualType ScalarTy) { 278 switch (ScalarTy->getScalarTypeKind()) { 279 case Type::STK_Bool: return CK_NoOp; 280 case Type::STK_CPointer: return CK_PointerToBoolean; 281 case Type::STK_BlockPointer: return CK_PointerToBoolean; 282 case Type::STK_ObjCObjectPointer: return CK_PointerToBoolean; 283 case Type::STK_MemberPointer: return CK_MemberPointerToBoolean; 284 case Type::STK_Integral: return CK_IntegralToBoolean; 285 case Type::STK_Floating: return CK_FloatingToBoolean; 286 case Type::STK_IntegralComplex: return CK_IntegralComplexToBoolean; 287 case Type::STK_FloatingComplex: return CK_FloatingComplexToBoolean; 288 } 289 return CK_Invalid; 290 } 291 292 /// \brief Used to prune the decls of Sema's UnusedFileScopedDecls vector. 293 static bool ShouldRemoveFromUnused(Sema *SemaRef, const DeclaratorDecl *D) { 294 if (D->isUsed()) 295 return true; 296 297 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 298 // UnusedFileScopedDecls stores the first declaration. 299 // The declaration may have become definition so check again. 300 const FunctionDecl *DeclToCheck; 301 if (FD->hasBody(DeclToCheck)) 302 return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck); 303 304 // Later redecls may add new information resulting in not having to warn, 305 // so check again. 306 DeclToCheck = FD->getMostRecentDeclaration(); 307 if (DeclToCheck != FD) 308 return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck); 309 } 310 311 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) { 312 // UnusedFileScopedDecls stores the first declaration. 313 // The declaration may have become definition so check again. 314 const VarDecl *DeclToCheck = VD->getDefinition(); 315 if (DeclToCheck) 316 return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck); 317 318 // Later redecls may add new information resulting in not having to warn, 319 // so check again. 320 DeclToCheck = VD->getMostRecentDeclaration(); 321 if (DeclToCheck != VD) 322 return !SemaRef->ShouldWarnIfUnusedFileScopedDecl(DeclToCheck); 323 } 324 325 return false; 326 } 327 328 namespace { 329 struct UndefinedInternal { 330 NamedDecl *decl; 331 FullSourceLoc useLoc; 332 333 UndefinedInternal(NamedDecl *decl, FullSourceLoc useLoc) 334 : decl(decl), useLoc(useLoc) {} 335 }; 336 337 bool operator<(const UndefinedInternal &l, const UndefinedInternal &r) { 338 return l.useLoc.isBeforeInTranslationUnitThan(r.useLoc); 339 } 340 } 341 342 /// checkUndefinedInternals - Check for undefined objects with internal linkage. 343 static void checkUndefinedInternals(Sema &S) { 344 if (S.UndefinedInternals.empty()) return; 345 346 // Collect all the still-undefined entities with internal linkage. 347 SmallVector<UndefinedInternal, 16> undefined; 348 for (llvm::DenseMap<NamedDecl*,SourceLocation>::iterator 349 i = S.UndefinedInternals.begin(), e = S.UndefinedInternals.end(); 350 i != e; ++i) { 351 NamedDecl *decl = i->first; 352 353 // Ignore attributes that have become invalid. 354 if (decl->isInvalidDecl()) continue; 355 356 // __attribute__((weakref)) is basically a definition. 357 if (decl->hasAttr<WeakRefAttr>()) continue; 358 359 if (FunctionDecl *fn = dyn_cast<FunctionDecl>(decl)) { 360 if (fn->isPure() || fn->hasBody()) 361 continue; 362 } else { 363 if (cast<VarDecl>(decl)->hasDefinition() != VarDecl::DeclarationOnly) 364 continue; 365 } 366 367 // We build a FullSourceLoc so that we can sort with array_pod_sort. 368 FullSourceLoc loc(i->second, S.Context.getSourceManager()); 369 undefined.push_back(UndefinedInternal(decl, loc)); 370 } 371 372 if (undefined.empty()) return; 373 374 // Sort (in order of use site) so that we're not (as) dependent on 375 // the iteration order through an llvm::DenseMap. 376 llvm::array_pod_sort(undefined.begin(), undefined.end()); 377 378 for (SmallVectorImpl<UndefinedInternal>::iterator 379 i = undefined.begin(), e = undefined.end(); i != e; ++i) { 380 NamedDecl *decl = i->decl; 381 S.Diag(decl->getLocation(), diag::warn_undefined_internal) 382 << isa<VarDecl>(decl) << decl; 383 S.Diag(i->useLoc, diag::note_used_here); 384 } 385 } 386 387 void Sema::LoadExternalWeakUndeclaredIdentifiers() { 388 if (!ExternalSource) 389 return; 390 391 SmallVector<std::pair<IdentifierInfo *, WeakInfo>, 4> WeakIDs; 392 ExternalSource->ReadWeakUndeclaredIdentifiers(WeakIDs); 393 for (unsigned I = 0, N = WeakIDs.size(); I != N; ++I) { 394 llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator Pos 395 = WeakUndeclaredIdentifiers.find(WeakIDs[I].first); 396 if (Pos != WeakUndeclaredIdentifiers.end()) 397 continue; 398 399 WeakUndeclaredIdentifiers.insert(WeakIDs[I]); 400 } 401 } 402 403 /// ActOnEndOfTranslationUnit - This is called at the very end of the 404 /// translation unit when EOF is reached and all but the top-level scope is 405 /// popped. 406 void Sema::ActOnEndOfTranslationUnit() { 407 // Only complete translation units define vtables and perform implicit 408 // instantiations. 409 if (TUKind == TU_Complete) { 410 // If any dynamic classes have their key function defined within 411 // this translation unit, then those vtables are considered "used" and must 412 // be emitted. 413 for (DynamicClassesType::iterator I = DynamicClasses.begin(ExternalSource), 414 E = DynamicClasses.end(); 415 I != E; ++I) { 416 assert(!(*I)->isDependentType() && 417 "Should not see dependent types here!"); 418 if (const CXXMethodDecl *KeyFunction = Context.getKeyFunction(*I)) { 419 const FunctionDecl *Definition = 0; 420 if (KeyFunction->hasBody(Definition)) 421 MarkVTableUsed(Definition->getLocation(), *I, true); 422 } 423 } 424 425 // If DefinedUsedVTables ends up marking any virtual member functions it 426 // might lead to more pending template instantiations, which we then need 427 // to instantiate. 428 DefineUsedVTables(); 429 430 // C++: Perform implicit template instantiations. 431 // 432 // FIXME: When we perform these implicit instantiations, we do not 433 // carefully keep track of the point of instantiation (C++ [temp.point]). 434 // This means that name lookup that occurs within the template 435 // instantiation will always happen at the end of the translation unit, 436 // so it will find some names that should not be found. Although this is 437 // common behavior for C++ compilers, it is technically wrong. In the 438 // future, we either need to be able to filter the results of name lookup 439 // or we need to perform template instantiations earlier. 440 PerformPendingInstantiations(); 441 } 442 443 // Remove file scoped decls that turned out to be used. 444 UnusedFileScopedDecls.erase(std::remove_if(UnusedFileScopedDecls.begin(0, 445 true), 446 UnusedFileScopedDecls.end(), 447 std::bind1st(std::ptr_fun(ShouldRemoveFromUnused), 448 this)), 449 UnusedFileScopedDecls.end()); 450 451 if (TUKind == TU_Prefix) { 452 // Translation unit prefixes don't need any of the checking below. 453 TUScope = 0; 454 return; 455 } 456 457 // Check for #pragma weak identifiers that were never declared 458 // FIXME: This will cause diagnostics to be emitted in a non-determinstic 459 // order! Iterating over a densemap like this is bad. 460 LoadExternalWeakUndeclaredIdentifiers(); 461 for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator 462 I = WeakUndeclaredIdentifiers.begin(), 463 E = WeakUndeclaredIdentifiers.end(); I != E; ++I) { 464 if (I->second.getUsed()) continue; 465 466 Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared) 467 << I->first; 468 } 469 470 if (TUKind == TU_Module) { 471 // Modules don't need any of the checking below. 472 TUScope = 0; 473 return; 474 } 475 476 // C99 6.9.2p2: 477 // A declaration of an identifier for an object that has file 478 // scope without an initializer, and without a storage-class 479 // specifier or with the storage-class specifier static, 480 // constitutes a tentative definition. If a translation unit 481 // contains one or more tentative definitions for an identifier, 482 // and the translation unit contains no external definition for 483 // that identifier, then the behavior is exactly as if the 484 // translation unit contains a file scope declaration of that 485 // identifier, with the composite type as of the end of the 486 // translation unit, with an initializer equal to 0. 487 llvm::SmallSet<VarDecl *, 32> Seen; 488 for (TentativeDefinitionsType::iterator 489 T = TentativeDefinitions.begin(ExternalSource), 490 TEnd = TentativeDefinitions.end(); 491 T != TEnd; ++T) 492 { 493 VarDecl *VD = (*T)->getActingDefinition(); 494 495 // If the tentative definition was completed, getActingDefinition() returns 496 // null. If we've already seen this variable before, insert()'s second 497 // return value is false. 498 if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD)) 499 continue; 500 501 if (const IncompleteArrayType *ArrayT 502 = Context.getAsIncompleteArrayType(VD->getType())) { 503 if (RequireCompleteType(VD->getLocation(), 504 ArrayT->getElementType(), 505 diag::err_tentative_def_incomplete_type_arr)) { 506 VD->setInvalidDecl(); 507 continue; 508 } 509 510 // Set the length of the array to 1 (C99 6.9.2p5). 511 Diag(VD->getLocation(), diag::warn_tentative_incomplete_array); 512 llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true); 513 QualType T = Context.getConstantArrayType(ArrayT->getElementType(), 514 One, ArrayType::Normal, 0); 515 VD->setType(T); 516 } else if (RequireCompleteType(VD->getLocation(), VD->getType(), 517 diag::err_tentative_def_incomplete_type)) 518 VD->setInvalidDecl(); 519 520 // Notify the consumer that we've completed a tentative definition. 521 if (!VD->isInvalidDecl()) 522 Consumer.CompleteTentativeDefinition(VD); 523 524 } 525 526 if (LangOpts.CPlusPlus0x && 527 Diags.getDiagnosticLevel(diag::warn_delegating_ctor_cycle, 528 SourceLocation()) 529 != DiagnosticsEngine::Ignored) 530 CheckDelegatingCtorCycles(); 531 532 // If there were errors, disable 'unused' warnings since they will mostly be 533 // noise. 534 if (!Diags.hasErrorOccurred()) { 535 // Output warning for unused file scoped decls. 536 for (UnusedFileScopedDeclsType::iterator 537 I = UnusedFileScopedDecls.begin(ExternalSource), 538 E = UnusedFileScopedDecls.end(); I != E; ++I) { 539 if (ShouldRemoveFromUnused(this, *I)) 540 continue; 541 542 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) { 543 const FunctionDecl *DiagD; 544 if (!FD->hasBody(DiagD)) 545 DiagD = FD; 546 if (DiagD->isDeleted()) 547 continue; // Deleted functions are supposed to be unused. 548 if (DiagD->isReferenced()) { 549 if (isa<CXXMethodDecl>(DiagD)) 550 Diag(DiagD->getLocation(), diag::warn_unneeded_member_function) 551 << DiagD->getDeclName(); 552 else 553 Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl) 554 << /*function*/0 << DiagD->getDeclName(); 555 } else { 556 Diag(DiagD->getLocation(), 557 isa<CXXMethodDecl>(DiagD) ? diag::warn_unused_member_function 558 : diag::warn_unused_function) 559 << DiagD->getDeclName(); 560 } 561 } else { 562 const VarDecl *DiagD = cast<VarDecl>(*I)->getDefinition(); 563 if (!DiagD) 564 DiagD = cast<VarDecl>(*I); 565 if (DiagD->isReferenced()) { 566 Diag(DiagD->getLocation(), diag::warn_unneeded_internal_decl) 567 << /*variable*/1 << DiagD->getDeclName(); 568 } else { 569 Diag(DiagD->getLocation(), diag::warn_unused_variable) 570 << DiagD->getDeclName(); 571 } 572 } 573 } 574 575 checkUndefinedInternals(*this); 576 } 577 578 // Check we've noticed that we're no longer parsing the initializer for every 579 // variable. If we miss cases, then at best we have a performance issue and 580 // at worst a rejects-valid bug. 581 assert(ParsingInitForAutoVars.empty() && 582 "Didn't unmark var as having its initializer parsed"); 583 584 TUScope = 0; 585 } 586 587 588 //===----------------------------------------------------------------------===// 589 // Helper functions. 590 //===----------------------------------------------------------------------===// 591 592 DeclContext *Sema::getFunctionLevelDeclContext() { 593 DeclContext *DC = CurContext; 594 595 while (isa<BlockDecl>(DC) || isa<EnumDecl>(DC)) 596 DC = DC->getParent(); 597 598 return DC; 599 } 600 601 /// getCurFunctionDecl - If inside of a function body, this returns a pointer 602 /// to the function decl for the function being parsed. If we're currently 603 /// in a 'block', this returns the containing context. 604 FunctionDecl *Sema::getCurFunctionDecl() { 605 DeclContext *DC = getFunctionLevelDeclContext(); 606 return dyn_cast<FunctionDecl>(DC); 607 } 608 609 ObjCMethodDecl *Sema::getCurMethodDecl() { 610 DeclContext *DC = getFunctionLevelDeclContext(); 611 return dyn_cast<ObjCMethodDecl>(DC); 612 } 613 614 NamedDecl *Sema::getCurFunctionOrMethodDecl() { 615 DeclContext *DC = getFunctionLevelDeclContext(); 616 if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC)) 617 return cast<NamedDecl>(DC); 618 return 0; 619 } 620 621 Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() { 622 if (!isActive()) 623 return; 624 625 if (llvm::Optional<TemplateDeductionInfo*> Info = SemaRef.isSFINAEContext()) { 626 switch (DiagnosticIDs::getDiagnosticSFINAEResponse(getDiagID())) { 627 case DiagnosticIDs::SFINAE_Report: 628 // We'll report the diagnostic below. 629 break; 630 631 case DiagnosticIDs::SFINAE_SubstitutionFailure: 632 // Count this failure so that we know that template argument deduction 633 // has failed. 634 ++SemaRef.NumSFINAEErrors; 635 SemaRef.Diags.setLastDiagnosticIgnored(); 636 SemaRef.Diags.Clear(); 637 Clear(); 638 return; 639 640 case DiagnosticIDs::SFINAE_AccessControl: { 641 // Per C++ Core Issue 1170, access control is part of SFINAE. 642 // Additionally, the AccessCheckingSFINAE flag can be used to temporary 643 // make access control a part of SFINAE for the purposes of checking 644 // type traits. 645 if (!SemaRef.AccessCheckingSFINAE && 646 !SemaRef.getLangOptions().CPlusPlus0x) 647 break; 648 649 SourceLocation Loc = getLocation(); 650 651 // Suppress this diagnostic. 652 ++SemaRef.NumSFINAEErrors; 653 SemaRef.Diags.setLastDiagnosticIgnored(); 654 SemaRef.Diags.Clear(); 655 Clear(); 656 657 // Now the diagnostic state is clear, produce a C++98 compatibility 658 // warning. 659 SemaRef.Diag(Loc, diag::warn_cxx98_compat_sfinae_access_control); 660 661 // The last diagnostic which Sema produced was ignored. Suppress any 662 // notes attached to it. 663 SemaRef.Diags.setLastDiagnosticIgnored(); 664 return; 665 } 666 667 case DiagnosticIDs::SFINAE_Suppress: 668 // Make a copy of this suppressed diagnostic and store it with the 669 // template-deduction information; 670 FlushCounts(); 671 Diagnostic DiagInfo(&SemaRef.Diags); 672 673 if (*Info) 674 (*Info)->addSuppressedDiagnostic(DiagInfo.getLocation(), 675 PartialDiagnostic(DiagInfo, 676 SemaRef.Context.getDiagAllocator())); 677 678 // Suppress this diagnostic. 679 SemaRef.Diags.setLastDiagnosticIgnored(); 680 SemaRef.Diags.Clear(); 681 Clear(); 682 return; 683 } 684 } 685 686 // Set up the context's printing policy based on our current state. 687 SemaRef.Context.setPrintingPolicy(SemaRef.getPrintingPolicy()); 688 689 // Emit the diagnostic. 690 if (!this->Emit()) 691 return; 692 693 // If this is not a note, and we're in a template instantiation 694 // that is different from the last template instantiation where 695 // we emitted an error, print a template instantiation 696 // backtrace. 697 if (!DiagnosticIDs::isBuiltinNote(DiagID) && 698 !SemaRef.ActiveTemplateInstantiations.empty() && 699 SemaRef.ActiveTemplateInstantiations.back() 700 != SemaRef.LastTemplateInstantiationErrorContext) { 701 SemaRef.PrintInstantiationStack(); 702 SemaRef.LastTemplateInstantiationErrorContext 703 = SemaRef.ActiveTemplateInstantiations.back(); 704 } 705 } 706 707 Sema::SemaDiagnosticBuilder Sema::Diag(SourceLocation Loc, unsigned DiagID) { 708 DiagnosticBuilder DB = Diags.Report(Loc, DiagID); 709 return SemaDiagnosticBuilder(DB, *this, DiagID); 710 } 711 712 Sema::SemaDiagnosticBuilder 713 Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) { 714 SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID())); 715 PD.Emit(Builder); 716 717 return Builder; 718 } 719 720 /// \brief Looks through the macro-expansion chain for the given 721 /// location, looking for a macro expansion with the given name. 722 /// If one is found, returns true and sets the location to that 723 /// expansion loc. 724 bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) { 725 SourceLocation loc = locref; 726 if (!loc.isMacroID()) return false; 727 728 // There's no good way right now to look at the intermediate 729 // expansions, so just jump to the expansion location. 730 loc = getSourceManager().getExpansionLoc(loc); 731 732 // If that's written with the name, stop here. 733 SmallVector<char, 16> buffer; 734 if (getPreprocessor().getSpelling(loc, buffer) == name) { 735 locref = loc; 736 return true; 737 } 738 return false; 739 } 740 741 /// \brief Determines the active Scope associated with the given declaration 742 /// context. 743 /// 744 /// This routine maps a declaration context to the active Scope object that 745 /// represents that declaration context in the parser. It is typically used 746 /// from "scope-less" code (e.g., template instantiation, lazy creation of 747 /// declarations) that injects a name for name-lookup purposes and, therefore, 748 /// must update the Scope. 749 /// 750 /// \returns The scope corresponding to the given declaraion context, or NULL 751 /// if no such scope is open. 752 Scope *Sema::getScopeForContext(DeclContext *Ctx) { 753 754 if (!Ctx) 755 return 0; 756 757 Ctx = Ctx->getPrimaryContext(); 758 for (Scope *S = getCurScope(); S; S = S->getParent()) { 759 // Ignore scopes that cannot have declarations. This is important for 760 // out-of-line definitions of static class members. 761 if (S->getFlags() & (Scope::DeclScope | Scope::TemplateParamScope)) 762 if (DeclContext *Entity = static_cast<DeclContext *> (S->getEntity())) 763 if (Ctx == Entity->getPrimaryContext()) 764 return S; 765 } 766 767 return 0; 768 } 769 770 /// \brief Enter a new function scope 771 void Sema::PushFunctionScope() { 772 if (FunctionScopes.size() == 1) { 773 // Use the "top" function scope rather than having to allocate 774 // memory for a new scope. 775 FunctionScopes.back()->Clear(); 776 FunctionScopes.push_back(FunctionScopes.back()); 777 return; 778 } 779 780 FunctionScopes.push_back(new FunctionScopeInfo(getDiagnostics())); 781 } 782 783 void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) { 784 FunctionScopes.push_back(new BlockScopeInfo(getDiagnostics(), 785 BlockScope, Block)); 786 } 787 788 void Sema::PopFunctionOrBlockScope(const AnalysisBasedWarnings::Policy *WP, 789 const Decl *D, const BlockExpr *blkExpr) { 790 FunctionScopeInfo *Scope = FunctionScopes.pop_back_val(); 791 assert(!FunctionScopes.empty() && "mismatched push/pop!"); 792 793 // Issue any analysis-based warnings. 794 if (WP && D) 795 AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr); 796 else { 797 for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator 798 i = Scope->PossiblyUnreachableDiags.begin(), 799 e = Scope->PossiblyUnreachableDiags.end(); 800 i != e; ++i) { 801 const sema::PossiblyUnreachableDiag &D = *i; 802 Diag(D.Loc, D.PD); 803 } 804 } 805 806 if (FunctionScopes.back() != Scope) { 807 delete Scope; 808 } 809 } 810 811 /// \brief Determine whether any errors occurred within this function/method/ 812 /// block. 813 bool Sema::hasAnyUnrecoverableErrorsInThisFunction() const { 814 return getCurFunction()->ErrorTrap.hasUnrecoverableErrorOccurred(); 815 } 816 817 BlockScopeInfo *Sema::getCurBlock() { 818 if (FunctionScopes.empty()) 819 return 0; 820 821 return dyn_cast<BlockScopeInfo>(FunctionScopes.back()); 822 } 823 824 // Pin this vtable to this file. 825 ExternalSemaSource::~ExternalSemaSource() {} 826 827 std::pair<ObjCMethodList, ObjCMethodList> 828 ExternalSemaSource::ReadMethodPool(Selector Sel) { 829 return std::pair<ObjCMethodList, ObjCMethodList>(); 830 } 831 832 void ExternalSemaSource::ReadKnownNamespaces( 833 SmallVectorImpl<NamespaceDecl *> &Namespaces) { 834 } 835 836 void PrettyDeclStackTraceEntry::print(raw_ostream &OS) const { 837 SourceLocation Loc = this->Loc; 838 if (!Loc.isValid() && TheDecl) Loc = TheDecl->getLocation(); 839 if (Loc.isValid()) { 840 Loc.print(OS, S.getSourceManager()); 841 OS << ": "; 842 } 843 OS << Message; 844 845 if (TheDecl && isa<NamedDecl>(TheDecl)) { 846 std::string Name = cast<NamedDecl>(TheDecl)->getNameAsString(); 847 if (!Name.empty()) 848 OS << " '" << Name << '\''; 849 } 850 851 OS << '\n'; 852 } 853 854 /// \brief Figure out if an expression could be turned into a call. 855 /// 856 /// Use this when trying to recover from an error where the programmer may have 857 /// written just the name of a function instead of actually calling it. 858 /// 859 /// \param E - The expression to examine. 860 /// \param ZeroArgCallReturnTy - If the expression can be turned into a call 861 /// with no arguments, this parameter is set to the type returned by such a 862 /// call; otherwise, it is set to an empty QualType. 863 /// \param OverloadSet - If the expression is an overloaded function 864 /// name, this parameter is populated with the decls of the various overloads. 865 bool Sema::isExprCallable(const Expr &E, QualType &ZeroArgCallReturnTy, 866 UnresolvedSetImpl &OverloadSet) { 867 ZeroArgCallReturnTy = QualType(); 868 OverloadSet.clear(); 869 870 if (E.getType() == Context.OverloadTy) { 871 OverloadExpr::FindResult FR = OverloadExpr::find(const_cast<Expr*>(&E)); 872 const OverloadExpr *Overloads = FR.Expression; 873 874 for (OverloadExpr::decls_iterator it = Overloads->decls_begin(), 875 DeclsEnd = Overloads->decls_end(); it != DeclsEnd; ++it) { 876 OverloadSet.addDecl(*it); 877 878 // Check whether the function is a non-template which takes no 879 // arguments. 880 if (const FunctionDecl *OverloadDecl 881 = dyn_cast<FunctionDecl>((*it)->getUnderlyingDecl())) { 882 if (OverloadDecl->getMinRequiredArguments() == 0) 883 ZeroArgCallReturnTy = OverloadDecl->getResultType(); 884 } 885 } 886 887 // Ignore overloads that are pointer-to-member constants. 888 if (FR.HasFormOfMemberPointer) 889 return false; 890 891 return true; 892 } 893 894 if (const DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E.IgnoreParens())) { 895 if (const FunctionDecl *Fun = dyn_cast<FunctionDecl>(DeclRef->getDecl())) { 896 if (Fun->getMinRequiredArguments() == 0) 897 ZeroArgCallReturnTy = Fun->getResultType(); 898 return true; 899 } 900 } 901 902 // We don't have an expression that's convenient to get a FunctionDecl from, 903 // but we can at least check if the type is "function of 0 arguments". 904 QualType ExprTy = E.getType(); 905 const FunctionType *FunTy = NULL; 906 QualType PointeeTy = ExprTy->getPointeeType(); 907 if (!PointeeTy.isNull()) 908 FunTy = PointeeTy->getAs<FunctionType>(); 909 if (!FunTy) 910 FunTy = ExprTy->getAs<FunctionType>(); 911 if (!FunTy && ExprTy == Context.BoundMemberTy) { 912 // Look for the bound-member type. If it's still overloaded, give up, 913 // although we probably should have fallen into the OverloadExpr case above 914 // if we actually have an overloaded bound member. 915 QualType BoundMemberTy = Expr::findBoundMemberType(&E); 916 if (!BoundMemberTy.isNull()) 917 FunTy = BoundMemberTy->castAs<FunctionType>(); 918 } 919 920 if (const FunctionProtoType *FPT = 921 dyn_cast_or_null<FunctionProtoType>(FunTy)) { 922 if (FPT->getNumArgs() == 0) 923 ZeroArgCallReturnTy = FunTy->getResultType(); 924 return true; 925 } 926 return false; 927 } 928 929 /// \brief Give notes for a set of overloads. 930 /// 931 /// A companion to isExprCallable. In cases when the name that the programmer 932 /// wrote was an overloaded function, we may be able to make some guesses about 933 /// plausible overloads based on their return types; such guesses can be handed 934 /// off to this method to be emitted as notes. 935 /// 936 /// \param Overloads - The overloads to note. 937 /// \param FinalNoteLoc - If we've suppressed printing some overloads due to 938 /// -fshow-overloads=best, this is the location to attach to the note about too 939 /// many candidates. Typically this will be the location of the original 940 /// ill-formed expression. 941 static void noteOverloads(Sema &S, const UnresolvedSetImpl &Overloads, 942 const SourceLocation FinalNoteLoc) { 943 int ShownOverloads = 0; 944 int SuppressedOverloads = 0; 945 for (UnresolvedSetImpl::iterator It = Overloads.begin(), 946 DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) { 947 // FIXME: Magic number for max shown overloads stolen from 948 // OverloadCandidateSet::NoteCandidates. 949 if (ShownOverloads >= 4 && 950 S.Diags.getShowOverloads() == DiagnosticsEngine::Ovl_Best) { 951 ++SuppressedOverloads; 952 continue; 953 } 954 955 NamedDecl *Fn = (*It)->getUnderlyingDecl(); 956 S.Diag(Fn->getLocStart(), diag::note_possible_target_of_call); 957 ++ShownOverloads; 958 } 959 960 if (SuppressedOverloads) 961 S.Diag(FinalNoteLoc, diag::note_ovl_too_many_candidates) 962 << SuppressedOverloads; 963 } 964 965 static void notePlausibleOverloads(Sema &S, SourceLocation Loc, 966 const UnresolvedSetImpl &Overloads, 967 bool (*IsPlausibleResult)(QualType)) { 968 if (!IsPlausibleResult) 969 return noteOverloads(S, Overloads, Loc); 970 971 UnresolvedSet<2> PlausibleOverloads; 972 for (OverloadExpr::decls_iterator It = Overloads.begin(), 973 DeclsEnd = Overloads.end(); It != DeclsEnd; ++It) { 974 const FunctionDecl *OverloadDecl = cast<FunctionDecl>(*It); 975 QualType OverloadResultTy = OverloadDecl->getResultType(); 976 if (IsPlausibleResult(OverloadResultTy)) 977 PlausibleOverloads.addDecl(It.getDecl()); 978 } 979 noteOverloads(S, PlausibleOverloads, Loc); 980 } 981 982 /// Determine whether the given expression can be called by just 983 /// putting parentheses after it. Notably, expressions with unary 984 /// operators can't be because the unary operator will start parsing 985 /// outside the call. 986 static bool IsCallableWithAppend(Expr *E) { 987 E = E->IgnoreImplicit(); 988 return (!isa<CStyleCastExpr>(E) && 989 !isa<UnaryOperator>(E) && 990 !isa<BinaryOperator>(E) && 991 !isa<CXXOperatorCallExpr>(E)); 992 } 993 994 bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD, 995 bool ForceComplain, 996 bool (*IsPlausibleResult)(QualType)) { 997 SourceLocation Loc = E.get()->getExprLoc(); 998 SourceRange Range = E.get()->getSourceRange(); 999 1000 QualType ZeroArgCallTy; 1001 UnresolvedSet<4> Overloads; 1002 if (isExprCallable(*E.get(), ZeroArgCallTy, Overloads) && 1003 !ZeroArgCallTy.isNull() && 1004 (!IsPlausibleResult || IsPlausibleResult(ZeroArgCallTy))) { 1005 // At this point, we know E is potentially callable with 0 1006 // arguments and that it returns something of a reasonable type, 1007 // so we can emit a fixit and carry on pretending that E was 1008 // actually a CallExpr. 1009 SourceLocation ParenInsertionLoc = 1010 PP.getLocForEndOfToken(Range.getEnd()); 1011 Diag(Loc, PD) 1012 << /*zero-arg*/ 1 << Range 1013 << (IsCallableWithAppend(E.get()) 1014 ? FixItHint::CreateInsertion(ParenInsertionLoc, "()") 1015 : FixItHint()); 1016 notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult); 1017 1018 // FIXME: Try this before emitting the fixit, and suppress diagnostics 1019 // while doing so. 1020 E = ActOnCallExpr(0, E.take(), ParenInsertionLoc, 1021 MultiExprArg(*this, 0, 0), 1022 ParenInsertionLoc.getLocWithOffset(1)); 1023 return true; 1024 } 1025 1026 if (!ForceComplain) return false; 1027 1028 Diag(Loc, PD) << /*not zero-arg*/ 0 << Range; 1029 notePlausibleOverloads(*this, Loc, Overloads, IsPlausibleResult); 1030 E = ExprError(); 1031 return true; 1032 } 1033