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/TargetInfo.h" 23 using namespace clang; 24 25 /// ConvertQualTypeToStringFn - This function is used to pretty print the 26 /// specified QualType as a string in diagnostics. 27 static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val, 28 const char *Modifier, unsigned ModLen, 29 const char *Argument, unsigned ArgLen, 30 llvm::SmallVectorImpl<char> &Output, 31 void *Cookie) { 32 ASTContext &Context = *static_cast<ASTContext*>(Cookie); 33 34 std::string S; 35 if (Kind == Diagnostic::ak_qualtype) { 36 assert(ModLen == 0 && ArgLen == 0 && 37 "Invalid modifier for QualType argument"); 38 39 QualType Ty(QualType::getFromOpaquePtr(reinterpret_cast<void*>(Val))); 40 41 // FIXME: Playing with std::string is really slow. 42 S = Ty.getAsString(Context.PrintingPolicy); 43 44 // If this is a sugared type (like a typedef, typeof, etc), then unwrap one 45 // level of the sugar so that the type is more obvious to the user. 46 QualType DesugaredTy = Ty->getDesugaredType(true); 47 DesugaredTy.setCVRQualifiers(DesugaredTy.getCVRQualifiers() | 48 Ty.getCVRQualifiers()); 49 50 if (Ty != DesugaredTy && 51 // If the desugared type is a vector type, we don't want to expand it, 52 // it will turn into an attribute mess. People want their "vec4". 53 !isa<VectorType>(DesugaredTy) && 54 55 // Don't desugar magic Objective-C types. 56 Ty.getUnqualifiedType() != Context.getObjCIdType() && 57 Ty.getUnqualifiedType() != Context.getObjCClassType() && 58 Ty.getUnqualifiedType() != Context.getObjCSelType() && 59 Ty.getUnqualifiedType() != Context.getObjCProtoType() && 60 61 // Not va_list. 62 Ty.getUnqualifiedType() != Context.getBuiltinVaListType()) { 63 S = "'"+S+"' (aka '"; 64 S += DesugaredTy.getAsString(Context.PrintingPolicy); 65 S += "')"; 66 Output.append(S.begin(), S.end()); 67 return; 68 } 69 70 } else if (Kind == Diagnostic::ak_declarationname) { 71 72 DeclarationName N = DeclarationName::getFromOpaqueInteger(Val); 73 S = N.getAsString(); 74 75 if (ModLen == 9 && !memcmp(Modifier, "objcclass", 9) && ArgLen == 0) 76 S = '+' + S; 77 else if (ModLen == 12 && !memcmp(Modifier, "objcinstance", 12) && ArgLen==0) 78 S = '-' + S; 79 else 80 assert(ModLen == 0 && ArgLen == 0 && 81 "Invalid modifier for DeclarationName argument"); 82 } else { 83 assert(Kind == Diagnostic::ak_nameddecl); 84 if (ModLen == 1 && Modifier[0] == 'q' && ArgLen == 0) 85 S = reinterpret_cast<NamedDecl*>(Val)->getQualifiedNameAsString(); 86 else { 87 assert(ModLen == 0 && ArgLen == 0 && 88 "Invalid modifier for NamedDecl* argument"); 89 S = reinterpret_cast<NamedDecl*>(Val)->getNameAsString(); 90 } 91 } 92 93 Output.push_back('\''); 94 Output.append(S.begin(), S.end()); 95 Output.push_back('\''); 96 } 97 98 99 static inline RecordDecl *CreateStructDecl(ASTContext &C, const char *Name) { 100 if (C.getLangOptions().CPlusPlus) 101 return CXXRecordDecl::Create(C, TagDecl::TK_struct, 102 C.getTranslationUnitDecl(), 103 SourceLocation(), &C.Idents.get(Name)); 104 105 return RecordDecl::Create(C, TagDecl::TK_struct, 106 C.getTranslationUnitDecl(), 107 SourceLocation(), &C.Idents.get(Name)); 108 } 109 110 void Sema::ActOnTranslationUnitScope(SourceLocation Loc, Scope *S) { 111 TUScope = S; 112 PushDeclContext(S, Context.getTranslationUnitDecl()); 113 114 if (PP.getTargetInfo().getPointerWidth(0) >= 64) { 115 // Install [u]int128_t for 64-bit targets. 116 PushOnScopeChains(TypedefDecl::Create(Context, CurContext, 117 SourceLocation(), 118 &Context.Idents.get("__int128_t"), 119 Context.Int128Ty), TUScope); 120 PushOnScopeChains(TypedefDecl::Create(Context, CurContext, 121 SourceLocation(), 122 &Context.Idents.get("__uint128_t"), 123 Context.UnsignedInt128Ty), TUScope); 124 } 125 126 127 if (!PP.getLangOptions().ObjC1) return; 128 129 // Built-in ObjC types may already be set by PCHReader (hence isNull checks). 130 if (Context.getObjCSelType().isNull()) { 131 // Synthesize "typedef struct objc_selector *SEL;" 132 RecordDecl *SelTag = CreateStructDecl(Context, "objc_selector"); 133 PushOnScopeChains(SelTag, TUScope); 134 135 QualType SelT = Context.getPointerType(Context.getTagDeclType(SelTag)); 136 TypedefDecl *SelTypedef = TypedefDecl::Create(Context, CurContext, 137 SourceLocation(), 138 &Context.Idents.get("SEL"), 139 SelT); 140 PushOnScopeChains(SelTypedef, TUScope); 141 Context.setObjCSelType(Context.getTypeDeclType(SelTypedef)); 142 } 143 144 // Synthesize "@class Protocol; 145 if (Context.getObjCProtoType().isNull()) { 146 ObjCInterfaceDecl *ProtocolDecl = 147 ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(), 148 &Context.Idents.get("Protocol"), 149 SourceLocation(), true); 150 Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl)); 151 PushOnScopeChains(ProtocolDecl, TUScope); 152 } 153 // Create the built-in typedef for 'id'. 154 if (Context.getObjCIdType().isNull()) { 155 TypedefDecl *IdTypedef = 156 TypedefDecl::Create( 157 Context, CurContext, SourceLocation(), &Context.Idents.get("id"), 158 Context.getObjCObjectPointerType(Context.ObjCBuiltinIdTy) 159 ); 160 PushOnScopeChains(IdTypedef, TUScope); 161 Context.setObjCIdType(Context.getTypeDeclType(IdTypedef)); 162 } 163 // Create the built-in typedef for 'Class'. 164 if (Context.getObjCClassType().isNull()) { 165 TypedefDecl *ClassTypedef = 166 TypedefDecl::Create( 167 Context, CurContext, SourceLocation(), &Context.Idents.get("Class"), 168 Context.getObjCObjectPointerType(Context.ObjCBuiltinClassTy) 169 ); 170 PushOnScopeChains(ClassTypedef, TUScope); 171 Context.setObjCClassType(Context.getTypeDeclType(ClassTypedef)); 172 } 173 } 174 175 Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer, 176 bool CompleteTranslationUnit) 177 : LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer), 178 Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()), 179 ExternalSource(0), CurContext(0), PreDeclaratorDC(0), 180 CurBlock(0), PackContext(0), IdResolver(pp.getLangOptions()), 181 GlobalNewDeleteDeclared(false), ExprEvalContext(PotentiallyEvaluated), 182 CompleteTranslationUnit(CompleteTranslationUnit), 183 NumSFINAEErrors(0), CurrentInstantiationScope(0) { 184 185 StdNamespace = 0; 186 TUScope = 0; 187 if (getLangOptions().CPlusPlus) 188 FieldCollector.reset(new CXXFieldCollector()); 189 190 // Tell diagnostics how to render things from the AST library. 191 PP.getDiagnostics().SetArgToStringFn(ConvertArgToStringFn, &Context); 192 } 193 194 /// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast. 195 /// If there is already an implicit cast, merge into the existing one. 196 /// If isLvalue, the result of the cast is an lvalue. 197 void Sema::ImpCastExprToType(Expr *&Expr, QualType Ty, 198 CastExpr::CastKind Kind, bool isLvalue) { 199 QualType ExprTy = Context.getCanonicalType(Expr->getType()); 200 QualType TypeTy = Context.getCanonicalType(Ty); 201 202 if (ExprTy == TypeTy) 203 return; 204 205 if (Expr->getType().getTypePtr()->isPointerType() && 206 Ty.getTypePtr()->isPointerType()) { 207 QualType ExprBaseType = 208 cast<PointerType>(ExprTy.getUnqualifiedType())->getPointeeType(); 209 QualType BaseType = 210 cast<PointerType>(TypeTy.getUnqualifiedType())->getPointeeType(); 211 if (ExprBaseType.getAddressSpace() != BaseType.getAddressSpace()) { 212 Diag(Expr->getExprLoc(), diag::err_implicit_pointer_address_space_cast) 213 << Expr->getSourceRange(); 214 } 215 } 216 217 if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(Expr)) { 218 ImpCast->setType(Ty); 219 ImpCast->setLvalueCast(isLvalue); 220 } else 221 Expr = new (Context) ImplicitCastExpr(Ty, Kind, Expr, 222 isLvalue); 223 } 224 225 void Sema::DeleteExpr(ExprTy *E) { 226 if (E) static_cast<Expr*>(E)->Destroy(Context); 227 } 228 void Sema::DeleteStmt(StmtTy *S) { 229 if (S) static_cast<Stmt*>(S)->Destroy(Context); 230 } 231 232 /// ActOnEndOfTranslationUnit - This is called at the very end of the 233 /// translation unit when EOF is reached and all but the top-level scope is 234 /// popped. 235 void Sema::ActOnEndOfTranslationUnit() { 236 // C++: Perform implicit template instantiations. 237 // 238 // FIXME: When we perform these implicit instantiations, we do not carefully 239 // keep track of the point of instantiation (C++ [temp.point]). This means 240 // that name lookup that occurs within the template instantiation will 241 // always happen at the end of the translation unit, so it will find 242 // some names that should not be found. Although this is common behavior 243 // for C++ compilers, it is technically wrong. In the future, we either need 244 // to be able to filter the results of name lookup or we need to perform 245 // template instantiations earlier. 246 PerformPendingImplicitInstantiations(); 247 248 // check for #pragma weak identifiers that were never declared 249 for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator 250 I = WeakUndeclaredIdentifiers.begin(), 251 E = WeakUndeclaredIdentifiers.end(); I != E; ++I) { 252 if (!I->second.getUsed()) 253 Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared) 254 << I->first; 255 } 256 257 if (!CompleteTranslationUnit) 258 return; 259 260 // C99 6.9.2p2: 261 // A declaration of an identifier for an object that has file 262 // scope without an initializer, and without a storage-class 263 // specifier or with the storage-class specifier static, 264 // constitutes a tentative definition. If a translation unit 265 // contains one or more tentative definitions for an identifier, 266 // and the translation unit contains no external definition for 267 // that identifier, then the behavior is exactly as if the 268 // translation unit contains a file scope declaration of that 269 // identifier, with the composite type as of the end of the 270 // translation unit, with an initializer equal to 0. 271 for (llvm::DenseMap<DeclarationName, VarDecl *>::iterator 272 D = TentativeDefinitions.begin(), 273 DEnd = TentativeDefinitions.end(); 274 D != DEnd; ++D) { 275 VarDecl *VD = D->second; 276 277 if (VD->isInvalidDecl() || !VD->isTentativeDefinition(Context)) 278 continue; 279 280 if (const IncompleteArrayType *ArrayT 281 = Context.getAsIncompleteArrayType(VD->getType())) { 282 if (RequireCompleteType(VD->getLocation(), 283 ArrayT->getElementType(), 284 diag::err_tentative_def_incomplete_type_arr)) 285 VD->setInvalidDecl(); 286 else { 287 // Set the length of the array to 1 (C99 6.9.2p5). 288 Diag(VD->getLocation(), diag::warn_tentative_incomplete_array); 289 llvm::APInt One(Context.getTypeSize(Context.getSizeType()), 290 true); 291 QualType T 292 = Context.getConstantArrayWithoutExprType(ArrayT->getElementType(), 293 One, ArrayType::Normal, 0); 294 VD->setType(T); 295 } 296 } else if (RequireCompleteType(VD->getLocation(), VD->getType(), 297 diag::err_tentative_def_incomplete_type)) 298 VD->setInvalidDecl(); 299 300 // Notify the consumer that we've completed a tentative definition. 301 if (!VD->isInvalidDecl()) 302 Consumer.CompleteTentativeDefinition(VD); 303 304 } 305 } 306 307 308 //===----------------------------------------------------------------------===// 309 // Helper functions. 310 //===----------------------------------------------------------------------===// 311 312 /// getCurFunctionDecl - If inside of a function body, this returns a pointer 313 /// to the function decl for the function being parsed. If we're currently 314 /// in a 'block', this returns the containing context. 315 FunctionDecl *Sema::getCurFunctionDecl() { 316 DeclContext *DC = CurContext; 317 while (isa<BlockDecl>(DC)) 318 DC = DC->getParent(); 319 return dyn_cast<FunctionDecl>(DC); 320 } 321 322 ObjCMethodDecl *Sema::getCurMethodDecl() { 323 DeclContext *DC = CurContext; 324 while (isa<BlockDecl>(DC)) 325 DC = DC->getParent(); 326 return dyn_cast<ObjCMethodDecl>(DC); 327 } 328 329 NamedDecl *Sema::getCurFunctionOrMethodDecl() { 330 DeclContext *DC = CurContext; 331 while (isa<BlockDecl>(DC)) 332 DC = DC->getParent(); 333 if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC)) 334 return cast<NamedDecl>(DC); 335 return 0; 336 } 337 338 Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() { 339 if (!this->Emit()) 340 return; 341 342 // If this is not a note, and we're in a template instantiation 343 // that is different from the last template instantiation where 344 // we emitted an error, print a template instantiation 345 // backtrace. 346 if (!SemaRef.Diags.isBuiltinNote(DiagID) && 347 !SemaRef.ActiveTemplateInstantiations.empty() && 348 SemaRef.ActiveTemplateInstantiations.back() 349 != SemaRef.LastTemplateInstantiationErrorContext) { 350 SemaRef.PrintInstantiationStack(); 351 SemaRef.LastTemplateInstantiationErrorContext 352 = SemaRef.ActiveTemplateInstantiations.back(); 353 } 354 } 355 356 void Sema::ActOnComment(SourceRange Comment) { 357 Context.Comments.push_back(Comment); 358 } 359