SemaStmt.cpp revision 206084
1223897Snwhitehorn//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// 2223897Snwhitehorn// 3223897Snwhitehorn// The LLVM Compiler Infrastructure 4287687Sdteske// 5223897Snwhitehorn// This file is distributed under the University of Illinois Open Source 6223897Snwhitehorn// License. See LICENSE.TXT for details. 7223897Snwhitehorn// 8223897Snwhitehorn//===----------------------------------------------------------------------===// 9223897Snwhitehorn// 10223897Snwhitehorn// This file implements semantic analysis for statements. 11223897Snwhitehorn// 12223897Snwhitehorn//===----------------------------------------------------------------------===// 13223897Snwhitehorn 14223897Snwhitehorn#include "Sema.h" 15223897Snwhitehorn#include "SemaInit.h" 16223897Snwhitehorn#include "clang/AST/APValue.h" 17223897Snwhitehorn#include "clang/AST/ASTContext.h" 18223897Snwhitehorn#include "clang/AST/DeclObjC.h" 19223897Snwhitehorn#include "clang/AST/ExprCXX.h" 20223897Snwhitehorn#include "clang/AST/ExprObjC.h" 21223897Snwhitehorn#include "clang/AST/StmtObjC.h" 22223897Snwhitehorn#include "clang/AST/StmtCXX.h" 23223897Snwhitehorn#include "clang/Lex/Preprocessor.h" 24223897Snwhitehorn#include "clang/Basic/TargetInfo.h" 25223897Snwhitehorn#include "llvm/ADT/STLExtras.h" 26223897Snwhitehorn#include "llvm/ADT/SmallVector.h" 27223897Snwhitehornusing namespace clang; 28223897Snwhitehorn 29257842SdteskeSema::OwningStmtResult Sema::ActOnExprStmt(FullExprArg expr) { 30257842Sdteske Expr *E = expr->takeAs<Expr>(); 31223897Snwhitehorn assert(E && "ActOnExprStmt(): missing expression"); 32257842Sdteske if (E->getType()->isObjCInterfaceType()) { 33257842Sdteske if (LangOpts.ObjCNonFragileABI) 34257842Sdteske Diag(E->getLocEnd(), diag::err_indirection_requires_nonfragile_object) 35257842Sdteske << E->getType(); 36257842Sdteske else 37257842Sdteske Diag(E->getLocEnd(), diag::err_direct_interface_unsupported) 38223897Snwhitehorn << E->getType(); 39257842Sdteske return StmtError(); 40223897Snwhitehorn } 41257842Sdteske // C99 6.8.3p2: The expression in an expression statement is evaluated as a 42257842Sdteske // void expression for its side effects. Conversion to void allows any 43257842Sdteske // operand, even incomplete types. 44257842Sdteske 45257842Sdteske // Same thing in for stmt first clause (when expr) and third clause. 46257842Sdteske return Owned(static_cast<Stmt*>(E)); 47224972Snwhitehorn} 48257842Sdteske 49257842Sdteske 50257842SdteskeSema::OwningStmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) { 51257842Sdteske return Owned(new (Context) NullStmt(SemiLoc)); 52257842Sdteske} 53257842Sdteske 54257842SdteskeSema::OwningStmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, 55257842Sdteske SourceLocation StartLoc, 56257842Sdteske SourceLocation EndLoc) { 57257842Sdteske DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 58257842Sdteske 59257842Sdteske // If we have an invalid decl, just return an error. 60257842Sdteske if (DG.isNull()) return StmtError(); 61257842Sdteske 62257842Sdteske return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 63257842Sdteske} 64257842Sdteske 65257842Sdteskevoid Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 66257842Sdteske DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 67257842Sdteske 68257842Sdteske // If we have an invalid decl, just return. 69257842Sdteske if (DG.isNull() || !DG.isSingleDecl()) return; 70257842Sdteske // suppress any potential 'unused variable' warning. 71257842Sdteske DG.getSingleDecl()->setUsed(); 72257842Sdteske} 73257842Sdteske 74257842Sdteskevoid Sema::DiagnoseUnusedExprResult(const Stmt *S) { 75257842Sdteske const Expr *E = dyn_cast_or_null<Expr>(S); 76257842Sdteske if (!E) 77257842Sdteske return; 78257842Sdteske 79257842Sdteske SourceLocation Loc; 80257842Sdteske SourceRange R1, R2; 81257842Sdteske if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 82257842Sdteske return; 83257842Sdteske 84257842Sdteske // Okay, we have an unused result. Depending on what the base expression is, 85257842Sdteske // we might want to make a more specific diagnostic. Check for one of these 86257842Sdteske // cases now. 87257842Sdteske unsigned DiagID = diag::warn_unused_expr; 88257842Sdteske E = E->IgnoreParens(); 89257842Sdteske if (isa<ObjCImplicitSetterGetterRefExpr>(E)) 90257842Sdteske DiagID = diag::warn_unused_property_expr; 91257842Sdteske 92257842Sdteske if (const CXXExprWithTemporaries *Temps = dyn_cast<CXXExprWithTemporaries>(E)) 93257842Sdteske E = Temps->getSubExpr(); 94257842Sdteske if (const CXXZeroInitValueExpr *Zero = dyn_cast<CXXZeroInitValueExpr>(E)) { 95257842Sdteske if (const RecordType *RecordT = Zero->getType()->getAs<RecordType>()) 96257842Sdteske if (CXXRecordDecl *RecordD = dyn_cast<CXXRecordDecl>(RecordT->getDecl())) 97257842Sdteske if (!RecordD->hasTrivialDestructor()) 98257842Sdteske return; 99257842Sdteske } 100257842Sdteske 101257842Sdteske if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 102257842Sdteske if (E->getType()->isVoidType()) 103257842Sdteske return; 104257842Sdteske 105257842Sdteske // If the callee has attribute pure, const, or warn_unused_result, warn with 106257842Sdteske // a more specific message to make it clear what is happening. 107257842Sdteske if (const Decl *FD = CE->getCalleeDecl()) { 108257842Sdteske if (FD->getAttr<WarnUnusedResultAttr>()) { 109257842Sdteske Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 110257842Sdteske return; 111257842Sdteske } 112257842Sdteske if (FD->getAttr<PureAttr>()) { 113257842Sdteske Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 114257842Sdteske return; 115257842Sdteske } 116257842Sdteske if (FD->getAttr<ConstAttr>()) { 117257842Sdteske Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 118257842Sdteske return; 119257842Sdteske } 120257842Sdteske } 121257842Sdteske } 122264488Sdteske else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 123257842Sdteske const ObjCMethodDecl *MD = ME->getMethodDecl(); 124257842Sdteske if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 125257842Sdteske Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 126257842Sdteske return; 127257842Sdteske } 128257842Sdteske } 129257842Sdteske Diag(Loc, DiagID) << R1 << R2; 130257842Sdteske} 131257842Sdteske 132257842SdteskeAction::OwningStmtResult 133257842SdteskeSema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 134224972Snwhitehorn MultiStmtArg elts, bool isStmtExpr) { 135224972Snwhitehorn unsigned NumElts = elts.size(); 136257842Sdteske Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 137224972Snwhitehorn // If we're in C89 mode, check that we don't have any decls after stmts. If 138257842Sdteske // so, emit an extension diagnostic. 139257842Sdteske if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 140257842Sdteske // Note that __extension__ can be around a decl. 141257842Sdteske unsigned i = 0; 142257842Sdteske // Skip over all declarations. 143257842Sdteske for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 144223897Snwhitehorn /*empty*/; 145257842Sdteske 146257842Sdteske // We found the end of the list or a statement. Scan for another declstmt. 147257842Sdteske for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 148257842Sdteske /*empty*/; 149257842Sdteske 150257749Sgjb if (i != NumElts) { 151257842Sdteske Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 152257842Sdteske Diag(D->getLocation(), diag::ext_mixed_decls_code); 153257749Sgjb } 154257842Sdteske } 155257842Sdteske // Warn about unused expressions in statements. 156257842Sdteske for (unsigned i = 0; i != NumElts; ++i) { 157280234Sallanjude // Ignore statements that are last in a statement expression. 158257842Sdteske if (isStmtExpr && i == NumElts - 1) 159280234Sallanjude continue; 160223897Snwhitehorn 161257842Sdteske DiagnoseUnusedExprResult(Elts[i]); 162287685Sdteske } 163280234Sallanjude 164257842Sdteske return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 165257842Sdteske} 166257842Sdteske 167Action::OwningStmtResult 168Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprArg lhsval, 169 SourceLocation DotDotDotLoc, ExprArg rhsval, 170 SourceLocation ColonLoc) { 171 assert((lhsval.get() != 0) && "missing expression in case statement"); 172 173 // C99 6.8.4.2p3: The expression shall be an integer constant. 174 // However, GCC allows any evaluatable integer expression. 175 Expr *LHSVal = static_cast<Expr*>(lhsval.get()); 176 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 177 VerifyIntegerConstantExpression(LHSVal)) 178 return StmtError(); 179 180 // GCC extension: The expression shall be an integer constant. 181 182 Expr *RHSVal = static_cast<Expr*>(rhsval.get()); 183 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 184 VerifyIntegerConstantExpression(RHSVal)) { 185 RHSVal = 0; // Recover by just forgetting about it. 186 rhsval = 0; 187 } 188 189 if (getSwitchStack().empty()) { 190 Diag(CaseLoc, diag::err_case_not_in_switch); 191 return StmtError(); 192 } 193 194 // Only now release the smart pointers. 195 lhsval.release(); 196 rhsval.release(); 197 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 198 ColonLoc); 199 getSwitchStack().back()->addSwitchCase(CS); 200 return Owned(CS); 201} 202 203/// ActOnCaseStmtBody - This installs a statement as the body of a case. 204void Sema::ActOnCaseStmtBody(StmtTy *caseStmt, StmtArg subStmt) { 205 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 206 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 207 CS->setSubStmt(SubStmt); 208} 209 210Action::OwningStmtResult 211Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 212 StmtArg subStmt, Scope *CurScope) { 213 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 214 215 if (getSwitchStack().empty()) { 216 Diag(DefaultLoc, diag::err_default_not_in_switch); 217 return Owned(SubStmt); 218 } 219 220 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 221 getSwitchStack().back()->addSwitchCase(DS); 222 return Owned(DS); 223} 224 225Action::OwningStmtResult 226Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 227 SourceLocation ColonLoc, StmtArg subStmt) { 228 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 229 // Look up the record for this label identifier. 230 LabelStmt *&LabelDecl = getLabelMap()[II]; 231 232 // If not forward referenced or defined already, just create a new LabelStmt. 233 if (LabelDecl == 0) 234 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt)); 235 236 assert(LabelDecl->getID() == II && "Label mismatch!"); 237 238 // Otherwise, this label was either forward reference or multiply defined. If 239 // multiply defined, reject it now. 240 if (LabelDecl->getSubStmt()) { 241 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 242 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 243 return Owned(SubStmt); 244 } 245 246 // Otherwise, this label was forward declared, and we just found its real 247 // definition. Fill in the forward definition and return it. 248 LabelDecl->setIdentLoc(IdentLoc); 249 LabelDecl->setSubStmt(SubStmt); 250 return Owned(LabelDecl); 251} 252 253Action::OwningStmtResult 254Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, DeclPtrTy CondVar, 255 StmtArg ThenVal, SourceLocation ElseLoc, 256 StmtArg ElseVal) { 257 OwningExprResult CondResult(CondVal.release()); 258 259 VarDecl *ConditionVar = 0; 260 if (CondVar.get()) { 261 ConditionVar = CondVar.getAs<VarDecl>(); 262 CondResult = CheckConditionVariable(ConditionVar); 263 if (CondResult.isInvalid()) 264 return StmtError(); 265 } 266 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 267 if (!ConditionExpr) 268 return StmtError(); 269 270 if (CheckBooleanCondition(ConditionExpr, IfLoc)) { 271 CondResult = ConditionExpr; 272 return StmtError(); 273 } 274 275 Stmt *thenStmt = ThenVal.takeAs<Stmt>(); 276 DiagnoseUnusedExprResult(thenStmt); 277 278 // Warn if the if block has a null body without an else value. 279 // this helps prevent bugs due to typos, such as 280 // if (condition); 281 // do_stuff(); 282 if (!ElseVal.get()) { 283 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 284 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 285 } 286 287 Stmt *elseStmt = ElseVal.takeAs<Stmt>(); 288 DiagnoseUnusedExprResult(elseStmt); 289 290 CondResult.release(); 291 return Owned(new (Context) IfStmt(IfLoc, ConditionVar, ConditionExpr, 292 thenStmt, ElseLoc, elseStmt)); 293} 294 295Action::OwningStmtResult 296Sema::ActOnStartOfSwitchStmt(FullExprArg cond, DeclPtrTy CondVar) { 297 OwningExprResult CondResult(cond.release()); 298 299 VarDecl *ConditionVar = 0; 300 if (CondVar.get()) { 301 ConditionVar = CondVar.getAs<VarDecl>(); 302 CondResult = CheckConditionVariable(ConditionVar); 303 if (CondResult.isInvalid()) 304 return StmtError(); 305 } 306 SwitchStmt *SS = new (Context) SwitchStmt(ConditionVar, 307 CondResult.takeAs<Expr>()); 308 getSwitchStack().push_back(SS); 309 return Owned(SS); 310} 311 312/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 313/// the specified width and sign. If an overflow occurs, detect it and emit 314/// the specified diagnostic. 315void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 316 unsigned NewWidth, bool NewSign, 317 SourceLocation Loc, 318 unsigned DiagID) { 319 // Perform a conversion to the promoted condition type if needed. 320 if (NewWidth > Val.getBitWidth()) { 321 // If this is an extension, just do it. 322 Val.extend(NewWidth); 323 Val.setIsSigned(NewSign); 324 325 // If the input was signed and negative and the output is 326 // unsigned, don't bother to warn: this is implementation-defined 327 // behavior. 328 // FIXME: Introduce a second, default-ignored warning for this case? 329 } else if (NewWidth < Val.getBitWidth()) { 330 // If this is a truncation, check for overflow. 331 llvm::APSInt ConvVal(Val); 332 ConvVal.trunc(NewWidth); 333 ConvVal.setIsSigned(NewSign); 334 ConvVal.extend(Val.getBitWidth()); 335 ConvVal.setIsSigned(Val.isSigned()); 336 if (ConvVal != Val) 337 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 338 339 // Regardless of whether a diagnostic was emitted, really do the 340 // truncation. 341 Val.trunc(NewWidth); 342 Val.setIsSigned(NewSign); 343 } else if (NewSign != Val.isSigned()) { 344 // Convert the sign to match the sign of the condition. This can cause 345 // overflow as well: unsigned(INTMIN) 346 // We don't diagnose this overflow, because it is implementation-defined 347 // behavior. 348 // FIXME: Introduce a second, default-ignored warning for this case? 349 llvm::APSInt OldVal(Val); 350 Val.setIsSigned(NewSign); 351 } 352} 353 354namespace { 355 struct CaseCompareFunctor { 356 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 357 const llvm::APSInt &RHS) { 358 return LHS.first < RHS; 359 } 360 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 361 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 362 return LHS.first < RHS.first; 363 } 364 bool operator()(const llvm::APSInt &LHS, 365 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 366 return LHS < RHS.first; 367 } 368 }; 369} 370 371/// CmpCaseVals - Comparison predicate for sorting case values. 372/// 373static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 374 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 375 if (lhs.first < rhs.first) 376 return true; 377 378 if (lhs.first == rhs.first && 379 lhs.second->getCaseLoc().getRawEncoding() 380 < rhs.second->getCaseLoc().getRawEncoding()) 381 return true; 382 return false; 383} 384 385/// CmpEnumVals - Comparison predicate for sorting enumeration values. 386/// 387static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 388 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 389{ 390 return lhs.first < rhs.first; 391} 392 393/// EqEnumVals - Comparison preficate for uniqing enumeration values. 394/// 395static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 396 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 397{ 398 return lhs.first == rhs.first; 399} 400 401/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 402/// potentially integral-promoted expression @p expr. 403static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 404 const ImplicitCastExpr *ImplicitCast = 405 dyn_cast_or_null<ImplicitCastExpr>(expr); 406 if (ImplicitCast != NULL) { 407 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 408 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 409 if (TypeBeforePromotion->isIntegralType()) { 410 return TypeBeforePromotion; 411 } 412 } 413 return expr->getType(); 414} 415 416/// \brief Check (and possibly convert) the condition in a switch 417/// statement in C++. 418static bool CheckCXXSwitchCondition(Sema &S, SourceLocation SwitchLoc, 419 Expr *&CondExpr) { 420 if (CondExpr->isTypeDependent()) 421 return false; 422 423 QualType CondType = CondExpr->getType(); 424 425 // C++ 6.4.2.p2: 426 // The condition shall be of integral type, enumeration type, or of a class 427 // type for which a single conversion function to integral or enumeration 428 // type exists (12.3). If the condition is of class type, the condition is 429 // converted by calling that conversion function, and the result of the 430 // conversion is used in place of the original condition for the remainder 431 // of this section. Integral promotions are performed. 432 433 // Make sure that the condition expression has a complete type, 434 // otherwise we'll never find any conversions. 435 if (S.RequireCompleteType(SwitchLoc, CondType, 436 S.PDiag(diag::err_switch_incomplete_class_type) 437 << CondExpr->getSourceRange())) 438 return true; 439 440 UnresolvedSet<4> ViableConversions; 441 UnresolvedSet<4> ExplicitConversions; 442 if (const RecordType *RecordTy = CondType->getAs<RecordType>()) { 443 const UnresolvedSetImpl *Conversions 444 = cast<CXXRecordDecl>(RecordTy->getDecl()) 445 ->getVisibleConversionFunctions(); 446 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 447 E = Conversions->end(); I != E; ++I) { 448 if (CXXConversionDecl *Conversion 449 = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) 450 if (Conversion->getConversionType().getNonReferenceType() 451 ->isIntegralType()) { 452 if (Conversion->isExplicit()) 453 ExplicitConversions.addDecl(I.getDecl(), I.getAccess()); 454 else 455 ViableConversions.addDecl(I.getDecl(), I.getAccess()); 456 } 457 } 458 459 switch (ViableConversions.size()) { 460 case 0: 461 if (ExplicitConversions.size() == 1) { 462 DeclAccessPair Found = ExplicitConversions[0]; 463 CXXConversionDecl *Conversion = 464 cast<CXXConversionDecl>(Found->getUnderlyingDecl()); 465 // The user probably meant to invoke the given explicit 466 // conversion; use it. 467 QualType ConvTy 468 = Conversion->getConversionType().getNonReferenceType(); 469 std::string TypeStr; 470 ConvTy.getAsStringInternal(TypeStr, S.Context.PrintingPolicy); 471 472 S.Diag(SwitchLoc, diag::err_switch_explicit_conversion) 473 << CondType << ConvTy << CondExpr->getSourceRange() 474 << FixItHint::CreateInsertion(CondExpr->getLocStart(), 475 "static_cast<" + TypeStr + ">(") 476 << FixItHint::CreateInsertion( 477 S.PP.getLocForEndOfToken(CondExpr->getLocEnd()), 478 ")"); 479 S.Diag(Conversion->getLocation(), diag::note_switch_conversion) 480 << ConvTy->isEnumeralType() << ConvTy; 481 482 // If we aren't in a SFINAE context, build a call to the 483 // explicit conversion function. 484 if (S.isSFINAEContext()) 485 return true; 486 487 S.CheckMemberOperatorAccess(CondExpr->getExprLoc(), 488 CondExpr, 0, Found); 489 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, Conversion); 490 } 491 492 // We'll complain below about a non-integral condition type. 493 break; 494 495 case 1: { 496 // Apply this conversion. 497 DeclAccessPair Found = ViableConversions[0]; 498 S.CheckMemberOperatorAccess(CondExpr->getExprLoc(), 499 CondExpr, 0, Found); 500 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, 501 cast<CXXConversionDecl>(Found->getUnderlyingDecl())); 502 break; 503 } 504 505 default: 506 S.Diag(SwitchLoc, diag::err_switch_multiple_conversions) 507 << CondType << CondExpr->getSourceRange(); 508 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { 509 CXXConversionDecl *Conv 510 = cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl()); 511 QualType ConvTy = Conv->getConversionType().getNonReferenceType(); 512 S.Diag(Conv->getLocation(), diag::note_switch_conversion) 513 << ConvTy->isEnumeralType() << ConvTy; 514 } 515 return true; 516 } 517 } 518 519 return false; 520} 521 522/// ActOnSwitchBodyError - This is called if there is an error parsing the 523/// body of the switch stmt instead of ActOnFinishSwitchStmt. 524void Sema::ActOnSwitchBodyError(SourceLocation SwitchLoc, StmtArg Switch, 525 StmtArg Body) { 526 // Keep the switch stack balanced. 527 assert(getSwitchStack().back() == (SwitchStmt*)Switch.get() && 528 "switch stack missing push/pop!"); 529 getSwitchStack().pop_back(); 530} 531 532Action::OwningStmtResult 533Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch, 534 StmtArg Body) { 535 Stmt *BodyStmt = Body.takeAs<Stmt>(); 536 537 SwitchStmt *SS = getSwitchStack().back(); 538 assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!"); 539 540 SS->setBody(BodyStmt, SwitchLoc); 541 getSwitchStack().pop_back(); 542 543 if (SS->getCond() == 0) { 544 SS->Destroy(Context); 545 return StmtError(); 546 } 547 548 Expr *CondExpr = SS->getCond(); 549 QualType CondTypeBeforePromotion = 550 GetTypeBeforeIntegralPromotion(CondExpr); 551 552 if (getLangOptions().CPlusPlus && 553 CheckCXXSwitchCondition(*this, SwitchLoc, CondExpr)) 554 return StmtError(); 555 556 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 557 UsualUnaryConversions(CondExpr); 558 QualType CondType = CondExpr->getType(); 559 SS->setCond(CondExpr); 560 561 // C++ 6.4.2.p2: 562 // Integral promotions are performed (on the switch condition). 563 // 564 // A case value unrepresentable by the original switch condition 565 // type (before the promotion) doesn't make sense, even when it can 566 // be represented by the promoted type. Therefore we need to find 567 // the pre-promotion type of the switch condition. 568 if (!CondExpr->isTypeDependent()) { 569 if (!CondType->isIntegerType()) { // C99 6.8.4.2p1 570 Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer) 571 << CondType << CondExpr->getSourceRange(); 572 return StmtError(); 573 } 574 575 if (CondTypeBeforePromotion->isBooleanType()) { 576 // switch(bool_expr) {...} is often a programmer error, e.g. 577 // switch(n && mask) { ... } // Doh - should be "n & mask". 578 // One can always use an if statement instead of switch(bool_expr). 579 Diag(SwitchLoc, diag::warn_bool_switch_condition) 580 << CondExpr->getSourceRange(); 581 } 582 } 583 584 // Get the bitwidth of the switched-on value before promotions. We must 585 // convert the integer case values to this width before comparison. 586 bool HasDependentValue 587 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 588 unsigned CondWidth 589 = HasDependentValue? 0 590 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 591 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 592 593 // Accumulate all of the case values in a vector so that we can sort them 594 // and detect duplicates. This vector contains the APInt for the case after 595 // it has been converted to the condition type. 596 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 597 CaseValsTy CaseVals; 598 599 // Keep track of any GNU case ranges we see. The APSInt is the low value. 600 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 601 CaseRangesTy CaseRanges; 602 603 DefaultStmt *TheDefaultStmt = 0; 604 605 bool CaseListIsErroneous = false; 606 607 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 608 SC = SC->getNextSwitchCase()) { 609 610 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 611 if (TheDefaultStmt) { 612 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 613 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 614 615 // FIXME: Remove the default statement from the switch block so that 616 // we'll return a valid AST. This requires recursing down the AST and 617 // finding it, not something we are set up to do right now. For now, 618 // just lop the entire switch stmt out of the AST. 619 CaseListIsErroneous = true; 620 } 621 TheDefaultStmt = DS; 622 623 } else { 624 CaseStmt *CS = cast<CaseStmt>(SC); 625 626 // We already verified that the expression has a i-c-e value (C99 627 // 6.8.4.2p3) - get that value now. 628 Expr *Lo = CS->getLHS(); 629 630 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 631 HasDependentValue = true; 632 break; 633 } 634 635 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 636 637 // Convert the value to the same width/sign as the condition. 638 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 639 CS->getLHS()->getLocStart(), 640 diag::warn_case_value_overflow); 641 642 // If the LHS is not the same type as the condition, insert an implicit 643 // cast. 644 ImpCastExprToType(Lo, CondType, CastExpr::CK_IntegralCast); 645 CS->setLHS(Lo); 646 647 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 648 if (CS->getRHS()) { 649 if (CS->getRHS()->isTypeDependent() || 650 CS->getRHS()->isValueDependent()) { 651 HasDependentValue = true; 652 break; 653 } 654 CaseRanges.push_back(std::make_pair(LoVal, CS)); 655 } else 656 CaseVals.push_back(std::make_pair(LoVal, CS)); 657 } 658 } 659 660 if (!HasDependentValue) { 661 // Sort all the scalar case values so we can easily detect duplicates. 662 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 663 664 if (!CaseVals.empty()) { 665 for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) { 666 if (CaseVals[i].first == CaseVals[i+1].first) { 667 // If we have a duplicate, report it. 668 Diag(CaseVals[i+1].second->getLHS()->getLocStart(), 669 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 670 Diag(CaseVals[i].second->getLHS()->getLocStart(), 671 diag::note_duplicate_case_prev); 672 // FIXME: We really want to remove the bogus case stmt from the 673 // substmt, but we have no way to do this right now. 674 CaseListIsErroneous = true; 675 } 676 } 677 } 678 679 // Detect duplicate case ranges, which usually don't exist at all in 680 // the first place. 681 if (!CaseRanges.empty()) { 682 // Sort all the case ranges by their low value so we can easily detect 683 // overlaps between ranges. 684 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 685 686 // Scan the ranges, computing the high values and removing empty ranges. 687 std::vector<llvm::APSInt> HiVals; 688 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 689 CaseStmt *CR = CaseRanges[i].second; 690 Expr *Hi = CR->getRHS(); 691 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 692 693 // Convert the value to the same width/sign as the condition. 694 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 695 CR->getRHS()->getLocStart(), 696 diag::warn_case_value_overflow); 697 698 // If the LHS is not the same type as the condition, insert an implicit 699 // cast. 700 ImpCastExprToType(Hi, CondType, CastExpr::CK_IntegralCast); 701 CR->setRHS(Hi); 702 703 // If the low value is bigger than the high value, the case is empty. 704 if (CaseRanges[i].first > HiVal) { 705 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 706 << SourceRange(CR->getLHS()->getLocStart(), 707 CR->getRHS()->getLocEnd()); 708 CaseRanges.erase(CaseRanges.begin()+i); 709 --i, --e; 710 continue; 711 } 712 HiVals.push_back(HiVal); 713 } 714 715 // Rescan the ranges, looking for overlap with singleton values and other 716 // ranges. Since the range list is sorted, we only need to compare case 717 // ranges with their neighbors. 718 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 719 llvm::APSInt &CRLo = CaseRanges[i].first; 720 llvm::APSInt &CRHi = HiVals[i]; 721 CaseStmt *CR = CaseRanges[i].second; 722 723 // Check to see whether the case range overlaps with any 724 // singleton cases. 725 CaseStmt *OverlapStmt = 0; 726 llvm::APSInt OverlapVal(32); 727 728 // Find the smallest value >= the lower bound. If I is in the 729 // case range, then we have overlap. 730 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 731 CaseVals.end(), CRLo, 732 CaseCompareFunctor()); 733 if (I != CaseVals.end() && I->first < CRHi) { 734 OverlapVal = I->first; // Found overlap with scalar. 735 OverlapStmt = I->second; 736 } 737 738 // Find the smallest value bigger than the upper bound. 739 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 740 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 741 OverlapVal = (I-1)->first; // Found overlap with scalar. 742 OverlapStmt = (I-1)->second; 743 } 744 745 // Check to see if this case stmt overlaps with the subsequent 746 // case range. 747 if (i && CRLo <= HiVals[i-1]) { 748 OverlapVal = HiVals[i-1]; // Found overlap with range. 749 OverlapStmt = CaseRanges[i-1].second; 750 } 751 752 if (OverlapStmt) { 753 // If we have a duplicate, report it. 754 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 755 << OverlapVal.toString(10); 756 Diag(OverlapStmt->getLHS()->getLocStart(), 757 diag::note_duplicate_case_prev); 758 // FIXME: We really want to remove the bogus case stmt from the 759 // substmt, but we have no way to do this right now. 760 CaseListIsErroneous = true; 761 } 762 } 763 } 764 765 // Check to see if switch is over an Enum and handles all of its 766 // values 767 const EnumType* ET = CondTypeBeforePromotion->getAs<EnumType>(); 768 // If switch has default case, then ignore it. 769 if (!CaseListIsErroneous && !TheDefaultStmt && ET) { 770 const EnumDecl *ED = ET->getDecl(); 771 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 772 EnumValsTy EnumVals; 773 774 // Gather all enum values, set their type and sort them, allowing easier comparison 775 // with CaseVals. 776 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); EDI != ED->enumerator_end(); EDI++) { 777 llvm::APSInt Val = (*EDI)->getInitVal(); 778 if(Val.getBitWidth() < CondWidth) 779 Val.extend(CondWidth); 780 Val.setIsSigned(CondIsSigned); 781 EnumVals.push_back(std::make_pair(Val, (*EDI))); 782 } 783 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 784 EnumValsTy::iterator EIend = std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 785 // See which case values aren't in enum 786 EnumValsTy::const_iterator EI = EnumVals.begin(); 787 for (CaseValsTy::const_iterator CI = CaseVals.begin(); CI != CaseVals.end(); CI++) { 788 while (EI != EIend && EI->first < CI->first) 789 EI++; 790 if (EI == EIend || EI->first > CI->first) 791 Diag(CI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 792 } 793 // See which of case ranges aren't in enum 794 EI = EnumVals.begin(); 795 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); RI != CaseRanges.end() && EI != EIend; RI++) { 796 while (EI != EIend && EI->first < RI->first) 797 EI++; 798 799 if (EI == EIend || EI->first != RI->first) { 800 Diag(RI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 801 } 802 803 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 804 while (EI != EIend && EI->first < Hi) 805 EI++; 806 if (EI == EIend || EI->first != Hi) 807 Diag(RI->second->getRHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 808 } 809 //Check which enum vals aren't in switch 810 CaseValsTy::const_iterator CI = CaseVals.begin(); 811 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 812 EI = EnumVals.begin(); 813 for (; EI != EIend; EI++) { 814 //Drop unneeded case values 815 llvm::APSInt CIVal; 816 while (CI != CaseVals.end() && CI->first < EI->first) 817 CI++; 818 819 if (CI != CaseVals.end() && CI->first == EI->first) 820 continue; 821 822 //Drop unneeded case ranges 823 for (; RI != CaseRanges.end(); RI++) { 824 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 825 if (EI->first <= Hi) 826 break; 827 } 828 829 if (RI == CaseRanges.end() || EI->first < RI->first) 830 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) << EI->second->getDeclName(); 831 } 832 } 833 } 834 835 // FIXME: If the case list was broken is some way, we don't have a good system 836 // to patch it up. Instead, just return the whole substmt as broken. 837 if (CaseListIsErroneous) 838 return StmtError(); 839 840 Switch.release(); 841 return Owned(SS); 842} 843 844Action::OwningStmtResult 845Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 846 DeclPtrTy CondVar, StmtArg Body) { 847 OwningExprResult CondResult(Cond.release()); 848 849 VarDecl *ConditionVar = 0; 850 if (CondVar.get()) { 851 ConditionVar = CondVar.getAs<VarDecl>(); 852 CondResult = CheckConditionVariable(ConditionVar); 853 if (CondResult.isInvalid()) 854 return StmtError(); 855 } 856 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 857 if (!ConditionExpr) 858 return StmtError(); 859 860 if (CheckBooleanCondition(ConditionExpr, WhileLoc)) { 861 CondResult = ConditionExpr; 862 return StmtError(); 863 } 864 865 Stmt *bodyStmt = Body.takeAs<Stmt>(); 866 DiagnoseUnusedExprResult(bodyStmt); 867 868 CondResult.release(); 869 return Owned(new (Context) WhileStmt(ConditionVar, ConditionExpr, bodyStmt, 870 WhileLoc)); 871} 872 873Action::OwningStmtResult 874Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body, 875 SourceLocation WhileLoc, SourceLocation CondLParen, 876 ExprArg Cond, SourceLocation CondRParen) { 877 Expr *condExpr = Cond.takeAs<Expr>(); 878 assert(condExpr && "ActOnDoStmt(): missing expression"); 879 880 if (CheckBooleanCondition(condExpr, DoLoc)) { 881 Cond = condExpr; 882 return StmtError(); 883 } 884 885 Stmt *bodyStmt = Body.takeAs<Stmt>(); 886 DiagnoseUnusedExprResult(bodyStmt); 887 888 Cond.release(); 889 return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc, 890 WhileLoc, CondRParen)); 891} 892 893Action::OwningStmtResult 894Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 895 StmtArg first, FullExprArg second, DeclPtrTy secondVar, 896 FullExprArg third, 897 SourceLocation RParenLoc, StmtArg body) { 898 Stmt *First = static_cast<Stmt*>(first.get()); 899 900 if (!getLangOptions().CPlusPlus) { 901 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 902 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 903 // declare identifiers for objects having storage class 'auto' or 904 // 'register'. 905 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 906 DI!=DE; ++DI) { 907 VarDecl *VD = dyn_cast<VarDecl>(*DI); 908 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 909 VD = 0; 910 if (VD == 0) 911 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 912 // FIXME: mark decl erroneous! 913 } 914 } 915 } 916 917 OwningExprResult SecondResult(second.release()); 918 VarDecl *ConditionVar = 0; 919 if (secondVar.get()) { 920 ConditionVar = secondVar.getAs<VarDecl>(); 921 SecondResult = CheckConditionVariable(ConditionVar); 922 if (SecondResult.isInvalid()) 923 return StmtError(); 924 } 925 926 Expr *Second = SecondResult.takeAs<Expr>(); 927 if (Second && CheckBooleanCondition(Second, ForLoc)) { 928 SecondResult = Second; 929 return StmtError(); 930 } 931 932 Expr *Third = third.release().takeAs<Expr>(); 933 Stmt *Body = static_cast<Stmt*>(body.get()); 934 935 DiagnoseUnusedExprResult(First); 936 DiagnoseUnusedExprResult(Third); 937 DiagnoseUnusedExprResult(Body); 938 939 first.release(); 940 body.release(); 941 return Owned(new (Context) ForStmt(First, Second, ConditionVar, Third, Body, 942 ForLoc, LParenLoc, RParenLoc)); 943} 944 945Action::OwningStmtResult 946Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 947 SourceLocation LParenLoc, 948 StmtArg first, ExprArg second, 949 SourceLocation RParenLoc, StmtArg body) { 950 Stmt *First = static_cast<Stmt*>(first.get()); 951 Expr *Second = static_cast<Expr*>(second.get()); 952 Stmt *Body = static_cast<Stmt*>(body.get()); 953 if (First) { 954 QualType FirstType; 955 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 956 if (!DS->isSingleDecl()) 957 return StmtError(Diag((*DS->decl_begin())->getLocation(), 958 diag::err_toomany_element_decls)); 959 960 Decl *D = DS->getSingleDecl(); 961 FirstType = cast<ValueDecl>(D)->getType(); 962 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 963 // declare identifiers for objects having storage class 'auto' or 964 // 'register'. 965 VarDecl *VD = cast<VarDecl>(D); 966 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 967 return StmtError(Diag(VD->getLocation(), 968 diag::err_non_variable_decl_in_for)); 969 } else { 970 if (cast<Expr>(First)->isLvalue(Context) != Expr::LV_Valid) 971 return StmtError(Diag(First->getLocStart(), 972 diag::err_selector_element_not_lvalue) 973 << First->getSourceRange()); 974 975 FirstType = static_cast<Expr*>(First)->getType(); 976 } 977 if (!FirstType->isObjCObjectPointerType() && 978 !FirstType->isBlockPointerType()) 979 Diag(ForLoc, diag::err_selector_element_type) 980 << FirstType << First->getSourceRange(); 981 } 982 if (Second) { 983 DefaultFunctionArrayLvalueConversion(Second); 984 QualType SecondType = Second->getType(); 985 if (!SecondType->isObjCObjectPointerType()) 986 Diag(ForLoc, diag::err_collection_expr_type) 987 << SecondType << Second->getSourceRange(); 988 } 989 first.release(); 990 second.release(); 991 body.release(); 992 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 993 ForLoc, RParenLoc)); 994} 995 996Action::OwningStmtResult 997Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 998 IdentifierInfo *LabelII) { 999 // Look up the record for this label identifier. 1000 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 1001 1002 // If we haven't seen this label yet, create a forward reference. 1003 if (LabelDecl == 0) 1004 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 1005 1006 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 1007} 1008 1009Action::OwningStmtResult 1010Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1011 ExprArg DestExp) { 1012 // Convert operand to void* 1013 Expr* E = DestExp.takeAs<Expr>(); 1014 if (!E->isTypeDependent()) { 1015 QualType ETy = E->getType(); 1016 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1017 AssignConvertType ConvTy = 1018 CheckSingleAssignmentConstraints(DestTy, E); 1019 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1020 return StmtError(); 1021 } 1022 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1023} 1024 1025Action::OwningStmtResult 1026Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1027 Scope *S = CurScope->getContinueParent(); 1028 if (!S) { 1029 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1030 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1031 } 1032 1033 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1034} 1035 1036Action::OwningStmtResult 1037Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1038 Scope *S = CurScope->getBreakParent(); 1039 if (!S) { 1040 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1041 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1042 } 1043 1044 return Owned(new (Context) BreakStmt(BreakLoc)); 1045} 1046 1047/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1048/// 1049Action::OwningStmtResult 1050Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1051 // If this is the first return we've seen in the block, infer the type of 1052 // the block from it. 1053 BlockScopeInfo *CurBlock = getCurBlock(); 1054 if (CurBlock->ReturnType.isNull()) { 1055 if (RetValExp) { 1056 // Don't call UsualUnaryConversions(), since we don't want to do 1057 // integer promotions here. 1058 DefaultFunctionArrayLvalueConversion(RetValExp); 1059 CurBlock->ReturnType = RetValExp->getType(); 1060 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1061 // We have to remove a 'const' added to copied-in variable which was 1062 // part of the implementation spec. and not the actual qualifier for 1063 // the variable. 1064 if (CDRE->isConstQualAdded()) 1065 CurBlock->ReturnType.removeConst(); 1066 } 1067 } else 1068 CurBlock->ReturnType = Context.VoidTy; 1069 } 1070 QualType FnRetType = CurBlock->ReturnType; 1071 1072 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 1073 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1074 << getCurFunctionOrMethodDecl()->getDeclName(); 1075 return StmtError(); 1076 } 1077 1078 // Otherwise, verify that this result type matches the previous one. We are 1079 // pickier with blocks than for normal functions because we don't have GCC 1080 // compatibility to worry about here. 1081 if (CurBlock->ReturnType->isVoidType()) { 1082 if (RetValExp) { 1083 Diag(ReturnLoc, diag::err_return_block_has_expr); 1084 RetValExp->Destroy(Context); 1085 RetValExp = 0; 1086 } 1087 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1088 } 1089 1090 if (!RetValExp) 1091 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1092 1093 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1094 // we have a non-void block with an expression, continue checking 1095 1096 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1097 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1098 // function return. 1099 1100 // In C++ the return statement is handled via a copy initialization. 1101 // the C version of which boils down to CheckSingleAssignmentConstraints. 1102 OwningExprResult Res = PerformCopyInitialization( 1103 InitializedEntity::InitializeResult(ReturnLoc, 1104 FnRetType), 1105 SourceLocation(), 1106 Owned(RetValExp)); 1107 if (Res.isInvalid()) { 1108 // FIXME: Cleanup temporaries here, anyway? 1109 return StmtError(); 1110 } 1111 1112 RetValExp = Res.takeAs<Expr>(); 1113 if (RetValExp) 1114 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1115 } 1116 1117 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1118} 1119 1120/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that 1121/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15). 1122static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType, 1123 Expr *RetExpr) { 1124 QualType ExprType = RetExpr->getType(); 1125 // - in a return statement in a function with ... 1126 // ... a class return type ... 1127 if (!RetType->isRecordType()) 1128 return false; 1129 // ... the same cv-unqualified type as the function return type ... 1130 if (!Ctx.hasSameUnqualifiedType(RetType, ExprType)) 1131 return false; 1132 // ... the expression is the name of a non-volatile automatic object ... 1133 // We ignore parentheses here. 1134 // FIXME: Is this compliant? 1135 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 1136 if (!DR) 1137 return false; 1138 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1139 if (!VD) 1140 return false; 1141 return VD->hasLocalStorage() && !VD->getType()->isReferenceType() 1142 && !VD->getType().isVolatileQualified(); 1143} 1144 1145Action::OwningStmtResult 1146Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) { 1147 Expr *RetValExp = rex.takeAs<Expr>(); 1148 if (getCurBlock()) 1149 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1150 1151 QualType FnRetType; 1152 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1153 FnRetType = FD->getResultType(); 1154 if (FD->hasAttr<NoReturnAttr>() || 1155 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1156 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1157 << getCurFunctionOrMethodDecl()->getDeclName(); 1158 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1159 FnRetType = MD->getResultType(); 1160 else // If we don't have a function/method context, bail. 1161 return StmtError(); 1162 1163 if (FnRetType->isVoidType()) { 1164 if (RetValExp && !RetValExp->isTypeDependent()) { 1165 // C99 6.8.6.4p1 (ext_ since GCC warns) 1166 unsigned D = diag::ext_return_has_expr; 1167 if (RetValExp->getType()->isVoidType()) 1168 D = diag::ext_return_has_void_expr; 1169 1170 // return (some void expression); is legal in C++. 1171 if (D != diag::ext_return_has_void_expr || 1172 !getLangOptions().CPlusPlus) { 1173 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1174 Diag(ReturnLoc, D) 1175 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1176 << RetValExp->getSourceRange(); 1177 } 1178 1179 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1180 } 1181 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1182 } 1183 1184 if (!RetValExp && !FnRetType->isDependentType()) { 1185 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1186 // C99 6.8.6.4p1 (ext_ since GCC warns) 1187 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1188 1189 if (FunctionDecl *FD = getCurFunctionDecl()) 1190 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1191 else 1192 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1193 return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0)); 1194 } 1195 1196 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1197 // we have a non-void function with an expression, continue checking 1198 1199 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1200 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1201 // function return. 1202 1203 // C++0x 12.8p15: When certain criteria are met, an implementation is 1204 // allowed to omit the copy construction of a class object, [...] 1205 // - in a return statement in a function with a class return type, when 1206 // the expression is the name of a non-volatile automatic object with 1207 // the same cv-unqualified type as the function return type, the copy 1208 // operation can be omitted [...] 1209 // C++0x 12.8p16: When the criteria for elision of a copy operation are met 1210 // and the object to be copied is designated by an lvalue, overload 1211 // resolution to select the constructor for the copy is first performed 1212 // as if the object were designated by an rvalue. 1213 // Note that we only compute Elidable if we're in C++0x, since we don't 1214 // care otherwise. 1215 bool Elidable = getLangOptions().CPlusPlus0x ? 1216 IsReturnCopyElidable(Context, FnRetType, RetValExp) : 1217 false; 1218 // FIXME: Elidable 1219 (void)Elidable; 1220 1221 // In C++ the return statement is handled via a copy initialization. 1222 // the C version of which boils down to CheckSingleAssignmentConstraints. 1223 OwningExprResult Res = PerformCopyInitialization( 1224 InitializedEntity::InitializeResult(ReturnLoc, 1225 FnRetType), 1226 SourceLocation(), 1227 Owned(RetValExp)); 1228 if (Res.isInvalid()) { 1229 // FIXME: Cleanup temporaries here, anyway? 1230 return StmtError(); 1231 } 1232 1233 RetValExp = Res.takeAs<Expr>(); 1234 if (RetValExp) 1235 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1236 } 1237 1238 if (RetValExp) 1239 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1240 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1241} 1242 1243/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1244/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1245/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1246/// provide a strong guidance to not use it. 1247/// 1248/// This method checks to see if the argument is an acceptable l-value and 1249/// returns false if it is a case we can handle. 1250static bool CheckAsmLValue(const Expr *E, Sema &S) { 1251 // Type dependent expressions will be checked during instantiation. 1252 if (E->isTypeDependent()) 1253 return false; 1254 1255 if (E->isLvalue(S.Context) == Expr::LV_Valid) 1256 return false; // Cool, this is an lvalue. 1257 1258 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1259 // are supposed to allow. 1260 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1261 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 1262 if (!S.getLangOptions().HeinousExtensions) 1263 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1264 << E->getSourceRange(); 1265 else 1266 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1267 << E->getSourceRange(); 1268 // Accept, even if we emitted an error diagnostic. 1269 return false; 1270 } 1271 1272 // None of the above, just randomly invalid non-lvalue. 1273 return true; 1274} 1275 1276 1277Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1278 bool IsSimple, 1279 bool IsVolatile, 1280 unsigned NumOutputs, 1281 unsigned NumInputs, 1282 IdentifierInfo **Names, 1283 MultiExprArg constraints, 1284 MultiExprArg exprs, 1285 ExprArg asmString, 1286 MultiExprArg clobbers, 1287 SourceLocation RParenLoc, 1288 bool MSAsm) { 1289 unsigned NumClobbers = clobbers.size(); 1290 StringLiteral **Constraints = 1291 reinterpret_cast<StringLiteral**>(constraints.get()); 1292 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 1293 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 1294 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1295 1296 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1297 1298 // The parser verifies that there is a string literal here. 1299 if (AsmString->isWide()) 1300 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1301 << AsmString->getSourceRange()); 1302 1303 for (unsigned i = 0; i != NumOutputs; i++) { 1304 StringLiteral *Literal = Constraints[i]; 1305 if (Literal->isWide()) 1306 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1307 << Literal->getSourceRange()); 1308 1309 llvm::StringRef OutputName; 1310 if (Names[i]) 1311 OutputName = Names[i]->getName(); 1312 1313 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1314 if (!Context.Target.validateOutputConstraint(Info)) 1315 return StmtError(Diag(Literal->getLocStart(), 1316 diag::err_asm_invalid_output_constraint) 1317 << Info.getConstraintStr()); 1318 1319 // Check that the output exprs are valid lvalues. 1320 Expr *OutputExpr = Exprs[i]; 1321 if (CheckAsmLValue(OutputExpr, *this)) { 1322 return StmtError(Diag(OutputExpr->getLocStart(), 1323 diag::err_asm_invalid_lvalue_in_output) 1324 << OutputExpr->getSourceRange()); 1325 } 1326 1327 OutputConstraintInfos.push_back(Info); 1328 } 1329 1330 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1331 1332 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1333 StringLiteral *Literal = Constraints[i]; 1334 if (Literal->isWide()) 1335 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1336 << Literal->getSourceRange()); 1337 1338 llvm::StringRef InputName; 1339 if (Names[i]) 1340 InputName = Names[i]->getName(); 1341 1342 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1343 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1344 NumOutputs, Info)) { 1345 return StmtError(Diag(Literal->getLocStart(), 1346 diag::err_asm_invalid_input_constraint) 1347 << Info.getConstraintStr()); 1348 } 1349 1350 Expr *InputExpr = Exprs[i]; 1351 1352 // Only allow void types for memory constraints. 1353 if (Info.allowsMemory() && !Info.allowsRegister()) { 1354 if (CheckAsmLValue(InputExpr, *this)) 1355 return StmtError(Diag(InputExpr->getLocStart(), 1356 diag::err_asm_invalid_lvalue_in_input) 1357 << Info.getConstraintStr() 1358 << InputExpr->getSourceRange()); 1359 } 1360 1361 if (Info.allowsRegister()) { 1362 if (InputExpr->getType()->isVoidType()) { 1363 return StmtError(Diag(InputExpr->getLocStart(), 1364 diag::err_asm_invalid_type_in_input) 1365 << InputExpr->getType() << Info.getConstraintStr() 1366 << InputExpr->getSourceRange()); 1367 } 1368 } 1369 1370 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1371 1372 InputConstraintInfos.push_back(Info); 1373 } 1374 1375 // Check that the clobbers are valid. 1376 for (unsigned i = 0; i != NumClobbers; i++) { 1377 StringLiteral *Literal = Clobbers[i]; 1378 if (Literal->isWide()) 1379 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1380 << Literal->getSourceRange()); 1381 1382 llvm::StringRef Clobber = Literal->getString(); 1383 1384 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1385 return StmtError(Diag(Literal->getLocStart(), 1386 diag::err_asm_unknown_register_name) << Clobber); 1387 } 1388 1389 constraints.release(); 1390 exprs.release(); 1391 asmString.release(); 1392 clobbers.release(); 1393 AsmStmt *NS = 1394 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1395 NumOutputs, NumInputs, Names, Constraints, Exprs, 1396 AsmString, NumClobbers, Clobbers, RParenLoc); 1397 // Validate the asm string, ensuring it makes sense given the operands we 1398 // have. 1399 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1400 unsigned DiagOffs; 1401 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1402 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1403 << AsmString->getSourceRange(); 1404 DeleteStmt(NS); 1405 return StmtError(); 1406 } 1407 1408 // Validate tied input operands for type mismatches. 1409 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1410 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1411 1412 // If this is a tied constraint, verify that the output and input have 1413 // either exactly the same type, or that they are int/ptr operands with the 1414 // same size (int/long, int*/long, are ok etc). 1415 if (!Info.hasTiedOperand()) continue; 1416 1417 unsigned TiedTo = Info.getTiedOperand(); 1418 Expr *OutputExpr = Exprs[TiedTo]; 1419 Expr *InputExpr = Exprs[i+NumOutputs]; 1420 QualType InTy = InputExpr->getType(); 1421 QualType OutTy = OutputExpr->getType(); 1422 if (Context.hasSameType(InTy, OutTy)) 1423 continue; // All types can be tied to themselves. 1424 1425 // Int/ptr operands have some special cases that we allow. 1426 if ((OutTy->isIntegerType() || OutTy->isPointerType()) && 1427 (InTy->isIntegerType() || InTy->isPointerType())) { 1428 1429 // They are ok if they are the same size. Tying void* to int is ok if 1430 // they are the same size, for example. This also allows tying void* to 1431 // int*. 1432 uint64_t OutSize = Context.getTypeSize(OutTy); 1433 uint64_t InSize = Context.getTypeSize(InTy); 1434 if (OutSize == InSize) 1435 continue; 1436 1437 // If the smaller input/output operand is not mentioned in the asm string, 1438 // then we can promote it and the asm string won't notice. Check this 1439 // case now. 1440 bool SmallerValueMentioned = false; 1441 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1442 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1443 if (!Piece.isOperand()) continue; 1444 1445 // If this is a reference to the input and if the input was the smaller 1446 // one, then we have to reject this asm. 1447 if (Piece.getOperandNo() == i+NumOutputs) { 1448 if (InSize < OutSize) { 1449 SmallerValueMentioned = true; 1450 break; 1451 } 1452 } 1453 1454 // If this is a reference to the input and if the input was the smaller 1455 // one, then we have to reject this asm. 1456 if (Piece.getOperandNo() == TiedTo) { 1457 if (InSize > OutSize) { 1458 SmallerValueMentioned = true; 1459 break; 1460 } 1461 } 1462 } 1463 1464 // If the smaller value wasn't mentioned in the asm string, and if the 1465 // output was a register, just extend the shorter one to the size of the 1466 // larger one. 1467 if (!SmallerValueMentioned && 1468 OutputConstraintInfos[TiedTo].allowsRegister()) 1469 continue; 1470 } 1471 1472 Diag(InputExpr->getLocStart(), 1473 diag::err_asm_tying_incompatible_types) 1474 << InTy << OutTy << OutputExpr->getSourceRange() 1475 << InputExpr->getSourceRange(); 1476 DeleteStmt(NS); 1477 return StmtError(); 1478 } 1479 1480 return Owned(NS); 1481} 1482 1483Action::OwningStmtResult 1484Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1485 SourceLocation RParen, DeclPtrTy Parm, 1486 StmtArg Body, StmtArg catchList) { 1487 Stmt *CatchList = catchList.takeAs<Stmt>(); 1488 ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>()); 1489 1490 // PVD == 0 implies @catch(...). 1491 if (PVD) { 1492 // If we already know the decl is invalid, reject it. 1493 if (PVD->isInvalidDecl()) 1494 return StmtError(); 1495 1496 if (!PVD->getType()->isObjCObjectPointerType()) 1497 return StmtError(Diag(PVD->getLocation(), 1498 diag::err_catch_param_not_objc_type)); 1499 if (PVD->getType()->isObjCQualifiedIdType()) 1500 return StmtError(Diag(PVD->getLocation(), 1501 diag::err_illegal_qualifiers_on_catch_parm)); 1502 } 1503 1504 ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen, 1505 PVD, Body.takeAs<Stmt>(), CatchList); 1506 return Owned(CatchList ? CatchList : CS); 1507} 1508 1509Action::OwningStmtResult 1510Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1511 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1512 static_cast<Stmt*>(Body.release()))); 1513} 1514 1515Action::OwningStmtResult 1516Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, 1517 StmtArg Try, StmtArg Catch, StmtArg Finally) { 1518 FunctionNeedsScopeChecking() = true; 1519 return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(), 1520 Catch.takeAs<Stmt>(), 1521 Finally.takeAs<Stmt>())); 1522} 1523 1524Action::OwningStmtResult 1525Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) { 1526 Expr *ThrowExpr = expr.takeAs<Expr>(); 1527 if (!ThrowExpr) { 1528 // @throw without an expression designates a rethrow (which much occur 1529 // in the context of an @catch clause). 1530 Scope *AtCatchParent = CurScope; 1531 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1532 AtCatchParent = AtCatchParent->getParent(); 1533 if (!AtCatchParent) 1534 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1535 } else { 1536 QualType ThrowType = ThrowExpr->getType(); 1537 // Make sure the expression type is an ObjC pointer or "void *". 1538 if (!ThrowType->isObjCObjectPointerType()) { 1539 const PointerType *PT = ThrowType->getAs<PointerType>(); 1540 if (!PT || !PT->getPointeeType()->isVoidType()) 1541 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1542 << ThrowExpr->getType() << ThrowExpr->getSourceRange()); 1543 } 1544 } 1545 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr)); 1546} 1547 1548Action::OwningStmtResult 1549Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1550 StmtArg SynchBody) { 1551 FunctionNeedsScopeChecking() = true; 1552 1553 // Make sure the expression type is an ObjC pointer or "void *". 1554 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1555 if (!SyncExpr->getType()->isObjCObjectPointerType()) { 1556 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1557 if (!PT || !PT->getPointeeType()->isVoidType()) 1558 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1559 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1560 } 1561 1562 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1563 SynchExpr.takeAs<Stmt>(), 1564 SynchBody.takeAs<Stmt>())); 1565} 1566 1567/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1568/// and creates a proper catch handler from them. 1569Action::OwningStmtResult 1570Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1571 StmtArg HandlerBlock) { 1572 // There's nothing to test that ActOnExceptionDecl didn't already test. 1573 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1574 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1575 HandlerBlock.takeAs<Stmt>())); 1576} 1577 1578class TypeWithHandler { 1579 QualType t; 1580 CXXCatchStmt *stmt; 1581public: 1582 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1583 : t(type), stmt(statement) {} 1584 1585 // An arbitrary order is fine as long as it places identical 1586 // types next to each other. 1587 bool operator<(const TypeWithHandler &y) const { 1588 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1589 return true; 1590 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1591 return false; 1592 else 1593 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1594 } 1595 1596 bool operator==(const TypeWithHandler& other) const { 1597 return t == other.t; 1598 } 1599 1600 QualType getQualType() const { return t; } 1601 CXXCatchStmt *getCatchStmt() const { return stmt; } 1602 SourceLocation getTypeSpecStartLoc() const { 1603 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1604 } 1605}; 1606 1607/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1608/// handlers and creates a try statement from them. 1609Action::OwningStmtResult 1610Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1611 MultiStmtArg RawHandlers) { 1612 unsigned NumHandlers = RawHandlers.size(); 1613 assert(NumHandlers > 0 && 1614 "The parser shouldn't call this if there are no handlers."); 1615 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1616 1617 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1618 1619 for (unsigned i = 0; i < NumHandlers; ++i) { 1620 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1621 if (!Handler->getExceptionDecl()) { 1622 if (i < NumHandlers - 1) 1623 return StmtError(Diag(Handler->getLocStart(), 1624 diag::err_early_catch_all)); 1625 1626 continue; 1627 } 1628 1629 const QualType CaughtType = Handler->getCaughtType(); 1630 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1631 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1632 } 1633 1634 // Detect handlers for the same type as an earlier one. 1635 if (NumHandlers > 1) { 1636 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1637 1638 TypeWithHandler prev = TypesWithHandlers[0]; 1639 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1640 TypeWithHandler curr = TypesWithHandlers[i]; 1641 1642 if (curr == prev) { 1643 Diag(curr.getTypeSpecStartLoc(), 1644 diag::warn_exception_caught_by_earlier_handler) 1645 << curr.getCatchStmt()->getCaughtType().getAsString(); 1646 Diag(prev.getTypeSpecStartLoc(), 1647 diag::note_previous_exception_handler) 1648 << prev.getCatchStmt()->getCaughtType().getAsString(); 1649 } 1650 1651 prev = curr; 1652 } 1653 } 1654 1655 // FIXME: We should detect handlers that cannot catch anything because an 1656 // earlier handler catches a superclass. Need to find a method that is not 1657 // quadratic for this. 1658 // Neither of these are explicitly forbidden, but every compiler detects them 1659 // and warns. 1660 1661 FunctionNeedsScopeChecking() = true; 1662 RawHandlers.release(); 1663 return Owned(CXXTryStmt::Create(Context, TryLoc, 1664 static_cast<Stmt*>(TryBlock.release()), 1665 Handlers, NumHandlers)); 1666} 1667