Sema.cpp revision 49a832bd499d6f61c23655f1fac99f0dd229756e
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 "Sema.h" 16#include "llvm/ADT/DenseMap.h" 17#include "clang/AST/ASTConsumer.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/AST/DeclObjC.h" 20#include "clang/AST/Expr.h" 21#include "clang/Lex/Preprocessor.h" 22#include "clang/Basic/PartialDiagnostic.h" 23#include "clang/Basic/TargetInfo.h" 24using namespace clang; 25 26/// Determines whether we should have an a.k.a. clause when 27/// pretty-printing a type. There are two main criteria: 28/// 29/// 1) Some types provide very minimal sugar that doesn't impede the 30/// user's understanding --- for example, elaborated type 31/// specifiers. If this is all the sugar we see, we don't want an 32/// a.k.a. clause. 33/// 2) Some types are technically sugared but are much more familiar 34/// when seen in their sugared form --- for example, va_list, 35/// vector types, and the magic Objective C types. We don't 36/// want to desugar these, even if we do produce an a.k.a. clause. 37static bool ShouldAKA(ASTContext &Context, QualType QT, 38 QualType& DesugaredQT) { 39 40 bool AKA = false; 41 QualifierCollector Qc; 42 43 while (true) { 44 const Type *Ty = Qc.strip(QT); 45 46 // Don't aka just because we saw an elaborated type... 47 if (isa<ElaboratedType>(Ty)) { 48 QT = cast<ElaboratedType>(Ty)->desugar(); 49 continue; 50 } 51 52 // ...or a qualified name type... 53 if (isa<QualifiedNameType>(Ty)) { 54 QT = cast<QualifiedNameType>(Ty)->desugar(); 55 continue; 56 } 57 58 // ...or a substituted template type parameter. 59 if (isa<SubstTemplateTypeParmType>(Ty)) { 60 QT = cast<SubstTemplateTypeParmType>(Ty)->desugar(); 61 continue; 62 } 63 64 // Don't desugar template specializations. 65 if (isa<TemplateSpecializationType>(Ty)) 66 break; 67 68 // Don't desugar magic Objective-C types. 69 if (QualType(Ty,0) == Context.getObjCIdType() || 70 QualType(Ty,0) == Context.getObjCClassType() || 71 QualType(Ty,0) == Context.getObjCSelType() || 72 QualType(Ty,0) == Context.getObjCProtoType()) 73 break; 74 75 // Don't desugar va_list. 76 if (QualType(Ty,0) == Context.getBuiltinVaListType()) 77 break; 78 79 // Otherwise, do a single-step desugar. 80 QualType Underlying; 81 bool IsSugar = false; 82 switch (Ty->getTypeClass()) { 83#define ABSTRACT_TYPE(Class, Base) 84#define TYPE(Class, Base) \ 85 case Type::Class: { \ 86 const Class##Type *CTy = cast<Class##Type>(Ty); \ 87 if (CTy->isSugared()) { \ 88 IsSugar = true; \ 89 Underlying = CTy->desugar(); \ 90 } \ 91 break; \ 92 } 93#include "clang/AST/TypeNodes.def" 94 } 95 96 // If it wasn't sugared, we're done. 97 if (!IsSugar) 98 break; 99 100 // If the desugared type is a vector type, we don't want to expand 101 // it, it will turn into an attribute mess. People want their "vec4". 102 if (isa<VectorType>(Underlying)) 103 break; 104 105 // Otherwise, we're tearing through something opaque; note that 106 // we'll eventually need an a.k.a. clause and keep going. 107 AKA = true; 108 QT = Underlying; 109 continue; 110 } 111 112 // If we ever tore through opaque sugar 113 if (AKA) { 114 DesugaredQT = Qc.apply(QT); 115 return true; 116 } 117 118 return false; 119} 120 121/// \brief Convert the given type to a string suitable for printing as part of 122/// a diagnostic. 123/// 124/// \param Context the context in which the type was allocated 125/// \param Ty the type to print 126static std::string ConvertTypeToDiagnosticString(ASTContext &Context, 127 QualType Ty) { 128 // FIXME: Playing with std::string is really slow. 129 std::string S = Ty.getAsString(Context.PrintingPolicy); 130 131 // Consider producing an a.k.a. clause if removing all the direct 132 // sugar gives us something "significantly different". 133 134 QualType DesugaredTy; 135 if (ShouldAKA(Context, Ty, DesugaredTy)) { 136 S = "'"+S+"' (aka '"; 137 S += DesugaredTy.getAsString(Context.PrintingPolicy); 138 S += "')"; 139 return S; 140 } 141 142 S = "'" + S + "'"; 143 return S; 144} 145 146/// ConvertQualTypeToStringFn - This function is used to pretty print the 147/// specified QualType as a string in diagnostics. 148static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val, 149 const char *Modifier, unsigned ModLen, 150 const char *Argument, unsigned ArgLen, 151 llvm::SmallVectorImpl<char> &Output, 152 void *Cookie) { 153 ASTContext &Context = *static_cast<ASTContext*>(Cookie); 154 155 std::string S; 156 bool NeedQuotes = true; 157 if (Kind == Diagnostic::ak_qualtype) { 158 assert(ModLen == 0 && ArgLen == 0 && 159 "Invalid modifier for QualType argument"); 160 161 QualType Ty(QualType::getFromOpaquePtr(reinterpret_cast<void*>(Val))); 162 S = ConvertTypeToDiagnosticString(Context, Ty); 163 NeedQuotes = false; 164 } else if (Kind == Diagnostic::ak_declarationname) { 165 166 DeclarationName N = DeclarationName::getFromOpaqueInteger(Val); 167 S = N.getAsString(); 168 169 if (ModLen == 9 && !memcmp(Modifier, "objcclass", 9) && ArgLen == 0) 170 S = '+' + S; 171 else if (ModLen == 12 && !memcmp(Modifier, "objcinstance", 12) && ArgLen==0) 172 S = '-' + S; 173 else 174 assert(ModLen == 0 && ArgLen == 0 && 175 "Invalid modifier for DeclarationName argument"); 176 } else if (Kind == Diagnostic::ak_nameddecl) { 177 bool Qualified; 178 if (ModLen == 1 && Modifier[0] == 'q' && ArgLen == 0) 179 Qualified = true; 180 else { 181 assert(ModLen == 0 && ArgLen == 0 && 182 "Invalid modifier for NamedDecl* argument"); 183 Qualified = false; 184 } 185 reinterpret_cast<NamedDecl*>(Val)->getNameForDiagnostic(S, 186 Context.PrintingPolicy, 187 Qualified); 188 } else if (Kind == Diagnostic::ak_nestednamespec) { 189 llvm::raw_string_ostream OS(S); 190 reinterpret_cast<NestedNameSpecifier*> (Val)->print(OS, 191 Context.PrintingPolicy); 192 NeedQuotes = false; 193 } else { 194 assert(Kind == Diagnostic::ak_declcontext); 195 DeclContext *DC = reinterpret_cast<DeclContext *> (Val); 196 NeedQuotes = false; 197 if (!DC) { 198 assert(false && "Should never have a null declaration context"); 199 S = "unknown context"; 200 } else if (DC->isTranslationUnit()) { 201 // FIXME: Get these strings from some localized place 202 if (Context.getLangOptions().CPlusPlus) 203 S = "the global namespace"; 204 else 205 S = "the global scope"; 206 } else if (TypeDecl *Type = dyn_cast<TypeDecl>(DC)) { 207 S = ConvertTypeToDiagnosticString(Context, Context.getTypeDeclType(Type)); 208 NeedQuotes = false; 209 } else { 210 // FIXME: Get these strings from some localized place 211 NamedDecl *ND = cast<NamedDecl>(DC); 212 if (isa<NamespaceDecl>(ND)) 213 S += "namespace "; 214 else if (isa<ObjCMethodDecl>(ND)) 215 S += "method "; 216 else if (isa<FunctionDecl>(ND)) 217 S += "function "; 218 219 S += "'"; 220 ND->getNameForDiagnostic(S, Context.PrintingPolicy, true); 221 S += "'"; 222 NeedQuotes = false; 223 } 224 } 225 226 if (NeedQuotes) 227 Output.push_back('\''); 228 229 Output.append(S.begin(), S.end()); 230 231 if (NeedQuotes) 232 Output.push_back('\''); 233} 234 235 236static inline RecordDecl *CreateStructDecl(ASTContext &C, const char *Name) { 237 if (C.getLangOptions().CPlusPlus) 238 return CXXRecordDecl::Create(C, TagDecl::TK_struct, 239 C.getTranslationUnitDecl(), 240 SourceLocation(), &C.Idents.get(Name)); 241 242 return RecordDecl::Create(C, TagDecl::TK_struct, 243 C.getTranslationUnitDecl(), 244 SourceLocation(), &C.Idents.get(Name)); 245} 246 247void Sema::ActOnTranslationUnitScope(SourceLocation Loc, Scope *S) { 248 TUScope = S; 249 PushDeclContext(S, Context.getTranslationUnitDecl()); 250 251 if (PP.getTargetInfo().getPointerWidth(0) >= 64) { 252 // Install [u]int128_t for 64-bit targets. 253 PushOnScopeChains(TypedefDecl::Create(Context, CurContext, 254 SourceLocation(), 255 &Context.Idents.get("__int128_t"), 256 Context.Int128Ty), TUScope); 257 PushOnScopeChains(TypedefDecl::Create(Context, CurContext, 258 SourceLocation(), 259 &Context.Idents.get("__uint128_t"), 260 Context.UnsignedInt128Ty), TUScope); 261 } 262 263 264 if (!PP.getLangOptions().ObjC1) return; 265 266 // Built-in ObjC types may already be set by PCHReader (hence isNull checks). 267 if (Context.getObjCSelType().isNull()) { 268 // Synthesize "typedef struct objc_selector *SEL;" 269 RecordDecl *SelTag = CreateStructDecl(Context, "objc_selector"); 270 PushOnScopeChains(SelTag, TUScope); 271 272 QualType SelT = Context.getPointerType(Context.getTagDeclType(SelTag)); 273 TypedefDecl *SelTypedef = TypedefDecl::Create(Context, CurContext, 274 SourceLocation(), 275 &Context.Idents.get("SEL"), 276 SelT); 277 PushOnScopeChains(SelTypedef, TUScope); 278 Context.setObjCSelType(Context.getTypeDeclType(SelTypedef)); 279 } 280 281 // Synthesize "@class Protocol; 282 if (Context.getObjCProtoType().isNull()) { 283 ObjCInterfaceDecl *ProtocolDecl = 284 ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(), 285 &Context.Idents.get("Protocol"), 286 SourceLocation(), true); 287 Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl)); 288 PushOnScopeChains(ProtocolDecl, TUScope); 289 } 290 // Create the built-in typedef for 'id'. 291 if (Context.getObjCIdType().isNull()) { 292 TypedefDecl *IdTypedef = 293 TypedefDecl::Create( 294 Context, CurContext, SourceLocation(), &Context.Idents.get("id"), 295 Context.getObjCObjectPointerType(Context.ObjCBuiltinIdTy) 296 ); 297 PushOnScopeChains(IdTypedef, TUScope); 298 Context.setObjCIdType(Context.getTypeDeclType(IdTypedef)); 299 Context.ObjCIdRedefinitionType = Context.getObjCIdType(); 300 } 301 // Create the built-in typedef for 'Class'. 302 if (Context.getObjCClassType().isNull()) { 303 TypedefDecl *ClassTypedef = 304 TypedefDecl::Create( 305 Context, CurContext, SourceLocation(), &Context.Idents.get("Class"), 306 Context.getObjCObjectPointerType(Context.ObjCBuiltinClassTy) 307 ); 308 PushOnScopeChains(ClassTypedef, TUScope); 309 Context.setObjCClassType(Context.getTypeDeclType(ClassTypedef)); 310 Context.ObjCClassRedefinitionType = Context.getObjCClassType(); 311 } 312} 313 314Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer, 315 bool CompleteTranslationUnit) 316 : LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer), 317 Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()), 318 ExternalSource(0), CodeCompleter(0), CurContext(0), 319 PreDeclaratorDC(0), CurBlock(0), PackContext(0), 320 IdResolver(pp.getLangOptions()), StdNamespace(0), StdBadAlloc(0), 321 GlobalNewDeleteDeclared(false), ExprEvalContext(PotentiallyEvaluated), 322 CompleteTranslationUnit(CompleteTranslationUnit), 323 NumSFINAEErrors(0), CurrentInstantiationScope(0) { 324 325 TUScope = 0; 326 if (getLangOptions().CPlusPlus) 327 FieldCollector.reset(new CXXFieldCollector()); 328 329 // Tell diagnostics how to render things from the AST library. 330 PP.getDiagnostics().SetArgToStringFn(ConvertArgToStringFn, &Context); 331} 332 333/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast. 334/// If there is already an implicit cast, merge into the existing one. 335/// If isLvalue, the result of the cast is an lvalue. 336void Sema::ImpCastExprToType(Expr *&Expr, QualType Ty, 337 CastExpr::CastKind Kind, bool isLvalue) { 338 QualType ExprTy = Context.getCanonicalType(Expr->getType()); 339 QualType TypeTy = Context.getCanonicalType(Ty); 340 341 if (ExprTy == TypeTy) 342 return; 343 344 if (Expr->getType().getTypePtr()->isPointerType() && 345 Ty.getTypePtr()->isPointerType()) { 346 QualType ExprBaseType = 347 cast<PointerType>(ExprTy.getUnqualifiedType())->getPointeeType(); 348 QualType BaseType = 349 cast<PointerType>(TypeTy.getUnqualifiedType())->getPointeeType(); 350 if (ExprBaseType.getAddressSpace() != BaseType.getAddressSpace()) { 351 Diag(Expr->getExprLoc(), diag::err_implicit_pointer_address_space_cast) 352 << Expr->getSourceRange(); 353 } 354 } 355 356 if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(Expr)) { 357 if (ImpCast->getCastKind() == Kind) { 358 ImpCast->setType(Ty); 359 ImpCast->setLvalueCast(isLvalue); 360 return; 361 } 362 } 363 364 Expr = new (Context) ImplicitCastExpr(Ty, Kind, Expr, isLvalue); 365} 366 367void Sema::DeleteExpr(ExprTy *E) { 368 if (E) static_cast<Expr*>(E)->Destroy(Context); 369} 370void Sema::DeleteStmt(StmtTy *S) { 371 if (S) static_cast<Stmt*>(S)->Destroy(Context); 372} 373 374/// ActOnEndOfTranslationUnit - This is called at the very end of the 375/// translation unit when EOF is reached and all but the top-level scope is 376/// popped. 377void Sema::ActOnEndOfTranslationUnit() { 378 // C++: Perform implicit template instantiations. 379 // 380 // FIXME: When we perform these implicit instantiations, we do not carefully 381 // keep track of the point of instantiation (C++ [temp.point]). This means 382 // that name lookup that occurs within the template instantiation will 383 // always happen at the end of the translation unit, so it will find 384 // some names that should not be found. Although this is common behavior 385 // for C++ compilers, it is technically wrong. In the future, we either need 386 // to be able to filter the results of name lookup or we need to perform 387 // template instantiations earlier. 388 PerformPendingImplicitInstantiations(); 389 390 // Check for #pragma weak identifiers that were never declared 391 // FIXME: This will cause diagnostics to be emitted in a non-determinstic 392 // order! Iterating over a densemap like this is bad. 393 for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator 394 I = WeakUndeclaredIdentifiers.begin(), 395 E = WeakUndeclaredIdentifiers.end(); I != E; ++I) { 396 if (I->second.getUsed()) continue; 397 398 Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared) 399 << I->first; 400 } 401 402 if (!CompleteTranslationUnit) 403 return; 404 405 // C99 6.9.2p2: 406 // A declaration of an identifier for an object that has file 407 // scope without an initializer, and without a storage-class 408 // specifier or with the storage-class specifier static, 409 // constitutes a tentative definition. If a translation unit 410 // contains one or more tentative definitions for an identifier, 411 // and the translation unit contains no external definition for 412 // that identifier, then the behavior is exactly as if the 413 // translation unit contains a file scope declaration of that 414 // identifier, with the composite type as of the end of the 415 // translation unit, with an initializer equal to 0. 416 for (unsigned i = 0, e = TentativeDefinitionList.size(); i != e; ++i) { 417 VarDecl *VD = TentativeDefinitions.lookup(TentativeDefinitionList[i]); 418 419 // If the tentative definition was completed, it will be in the list, but 420 // not the map. 421 if (VD == 0 || VD->isInvalidDecl() || !VD->isTentativeDefinition(Context)) 422 continue; 423 424 if (const IncompleteArrayType *ArrayT 425 = Context.getAsIncompleteArrayType(VD->getType())) { 426 if (RequireCompleteType(VD->getLocation(), 427 ArrayT->getElementType(), 428 diag::err_tentative_def_incomplete_type_arr)) { 429 VD->setInvalidDecl(); 430 continue; 431 } 432 433 // Set the length of the array to 1 (C99 6.9.2p5). 434 Diag(VD->getLocation(), diag::warn_tentative_incomplete_array); 435 llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true); 436 QualType T = Context.getConstantArrayType(ArrayT->getElementType(), 437 One, ArrayType::Normal, 0); 438 VD->setType(T); 439 } else if (RequireCompleteType(VD->getLocation(), VD->getType(), 440 diag::err_tentative_def_incomplete_type)) 441 VD->setInvalidDecl(); 442 443 // Notify the consumer that we've completed a tentative definition. 444 if (!VD->isInvalidDecl()) 445 Consumer.CompleteTentativeDefinition(VD); 446 447 } 448} 449 450 451//===----------------------------------------------------------------------===// 452// Helper functions. 453//===----------------------------------------------------------------------===// 454 455DeclContext *Sema::getFunctionLevelDeclContext() { 456 DeclContext *DC = PreDeclaratorDC ? PreDeclaratorDC : CurContext; 457 458 while (isa<BlockDecl>(DC)) 459 DC = DC->getParent(); 460 461 return DC; 462} 463 464/// getCurFunctionDecl - If inside of a function body, this returns a pointer 465/// to the function decl for the function being parsed. If we're currently 466/// in a 'block', this returns the containing context. 467FunctionDecl *Sema::getCurFunctionDecl() { 468 DeclContext *DC = getFunctionLevelDeclContext(); 469 return dyn_cast<FunctionDecl>(DC); 470} 471 472ObjCMethodDecl *Sema::getCurMethodDecl() { 473 DeclContext *DC = getFunctionLevelDeclContext(); 474 return dyn_cast<ObjCMethodDecl>(DC); 475} 476 477NamedDecl *Sema::getCurFunctionOrMethodDecl() { 478 DeclContext *DC = getFunctionLevelDeclContext(); 479 if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC)) 480 return cast<NamedDecl>(DC); 481 return 0; 482} 483 484Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() { 485 if (!this->Emit()) 486 return; 487 488 // If this is not a note, and we're in a template instantiation 489 // that is different from the last template instantiation where 490 // we emitted an error, print a template instantiation 491 // backtrace. 492 if (!SemaRef.Diags.isBuiltinNote(DiagID) && 493 !SemaRef.ActiveTemplateInstantiations.empty() && 494 SemaRef.ActiveTemplateInstantiations.back() 495 != SemaRef.LastTemplateInstantiationErrorContext) { 496 SemaRef.PrintInstantiationStack(); 497 SemaRef.LastTemplateInstantiationErrorContext 498 = SemaRef.ActiveTemplateInstantiations.back(); 499 } 500} 501 502Sema::SemaDiagnosticBuilder 503Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) { 504 SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID())); 505 PD.Emit(Builder); 506 507 return Builder; 508} 509 510void Sema::ActOnComment(SourceRange Comment) { 511 Context.Comments.push_back(Comment); 512} 513 514