SemaStmt.cpp revision d86c477fb5d3fc34864afecbbb5443da9355e8fb
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// 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 semantic analysis for statements. 11// 12//===----------------------------------------------------------------------===// 13 14#include "Sema.h" 15#include "SemaInit.h" 16#include "clang/AST/APValue.h" 17#include "clang/AST/ASTContext.h" 18#include "clang/AST/DeclObjC.h" 19#include "clang/AST/ExprCXX.h" 20#include "clang/AST/ExprObjC.h" 21#include "clang/AST/StmtObjC.h" 22#include "clang/AST/StmtCXX.h" 23#include "clang/AST/TypeLoc.h" 24#include "clang/Lex/Preprocessor.h" 25#include "clang/Basic/TargetInfo.h" 26#include "llvm/ADT/STLExtras.h" 27#include "llvm/ADT/SmallVector.h" 28using namespace clang; 29 30Sema::OwningStmtResult Sema::ActOnExprStmt(FullExprArg expr) { 31 Expr *E = expr->takeAs<Expr>(); 32 assert(E && "ActOnExprStmt(): missing expression"); 33 if (E->getType()->isObjCInterfaceType()) { 34 if (LangOpts.ObjCNonFragileABI) 35 Diag(E->getLocEnd(), diag::err_indirection_requires_nonfragile_object) 36 << E->getType(); 37 else 38 Diag(E->getLocEnd(), diag::err_direct_interface_unsupported) 39 << E->getType(); 40 return StmtError(); 41 } 42 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 43 // void expression for its side effects. Conversion to void allows any 44 // operand, even incomplete types. 45 46 // Same thing in for stmt first clause (when expr) and third clause. 47 return Owned(static_cast<Stmt*>(E)); 48} 49 50 51Sema::OwningStmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) { 52 return Owned(new (Context) NullStmt(SemiLoc)); 53} 54 55Sema::OwningStmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, 56 SourceLocation StartLoc, 57 SourceLocation EndLoc) { 58 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 59 60 // If we have an invalid decl, just return an error. 61 if (DG.isNull()) return StmtError(); 62 63 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 64} 65 66void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 67 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 68 69 // If we have an invalid decl, just return. 70 if (DG.isNull() || !DG.isSingleDecl()) return; 71 // suppress any potential 'unused variable' warning. 72 DG.getSingleDecl()->setUsed(); 73} 74 75void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 76 const Expr *E = dyn_cast_or_null<Expr>(S); 77 if (!E) 78 return; 79 80 SourceLocation Loc; 81 SourceRange R1, R2; 82 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 83 return; 84 85 // Okay, we have an unused result. Depending on what the base expression is, 86 // we might want to make a more specific diagnostic. Check for one of these 87 // cases now. 88 unsigned DiagID = diag::warn_unused_expr; 89 E = E->IgnoreParens(); 90 if (isa<ObjCImplicitSetterGetterRefExpr>(E)) 91 DiagID = diag::warn_unused_property_expr; 92 93 if (const CXXExprWithTemporaries *Temps = dyn_cast<CXXExprWithTemporaries>(E)) 94 E = Temps->getSubExpr(); 95 if (const CXXZeroInitValueExpr *Zero = dyn_cast<CXXZeroInitValueExpr>(E)) { 96 if (const RecordType *RecordT = Zero->getType()->getAs<RecordType>()) 97 if (CXXRecordDecl *RecordD = dyn_cast<CXXRecordDecl>(RecordT->getDecl())) 98 if (!RecordD->hasTrivialDestructor()) 99 return; 100 } 101 102 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 103 if (E->getType()->isVoidType()) 104 return; 105 106 // If the callee has attribute pure, const, or warn_unused_result, warn with 107 // a more specific message to make it clear what is happening. 108 if (const Decl *FD = CE->getCalleeDecl()) { 109 if (FD->getAttr<WarnUnusedResultAttr>()) { 110 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 111 return; 112 } 113 if (FD->getAttr<PureAttr>()) { 114 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 115 return; 116 } 117 if (FD->getAttr<ConstAttr>()) { 118 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 119 return; 120 } 121 } 122 } 123 else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 124 const ObjCMethodDecl *MD = ME->getMethodDecl(); 125 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 126 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 127 return; 128 } 129 } else if (const CXXFunctionalCastExpr *FC 130 = dyn_cast<CXXFunctionalCastExpr>(E)) { 131 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 132 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 133 return; 134 } 135 // Diagnose "(void*) blah" as a typo for "(void) blah". 136 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 137 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 138 QualType T = TI->getType(); 139 140 // We really do want to use the non-canonical type here. 141 if (T == Context.VoidPtrTy) { 142 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 143 144 Diag(Loc, diag::warn_unused_voidptr) 145 << FixItHint::CreateRemoval(TL.getStarLoc()); 146 return; 147 } 148 } 149 150 Diag(Loc, DiagID) << R1 << R2; 151} 152 153Action::OwningStmtResult 154Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 155 MultiStmtArg elts, bool isStmtExpr) { 156 unsigned NumElts = elts.size(); 157 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 158 // If we're in C89 mode, check that we don't have any decls after stmts. If 159 // so, emit an extension diagnostic. 160 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 161 // Note that __extension__ can be around a decl. 162 unsigned i = 0; 163 // Skip over all declarations. 164 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 165 /*empty*/; 166 167 // We found the end of the list or a statement. Scan for another declstmt. 168 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 169 /*empty*/; 170 171 if (i != NumElts) { 172 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 173 Diag(D->getLocation(), diag::ext_mixed_decls_code); 174 } 175 } 176 // Warn about unused expressions in statements. 177 for (unsigned i = 0; i != NumElts; ++i) { 178 // Ignore statements that are last in a statement expression. 179 if (isStmtExpr && i == NumElts - 1) 180 continue; 181 182 DiagnoseUnusedExprResult(Elts[i]); 183 } 184 185 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 186} 187 188Action::OwningStmtResult 189Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprArg lhsval, 190 SourceLocation DotDotDotLoc, ExprArg rhsval, 191 SourceLocation ColonLoc) { 192 assert((lhsval.get() != 0) && "missing expression in case statement"); 193 194 // C99 6.8.4.2p3: The expression shall be an integer constant. 195 // However, GCC allows any evaluatable integer expression. 196 Expr *LHSVal = static_cast<Expr*>(lhsval.get()); 197 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 198 VerifyIntegerConstantExpression(LHSVal)) 199 return StmtError(); 200 201 // GCC extension: The expression shall be an integer constant. 202 203 Expr *RHSVal = static_cast<Expr*>(rhsval.get()); 204 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 205 VerifyIntegerConstantExpression(RHSVal)) { 206 RHSVal = 0; // Recover by just forgetting about it. 207 rhsval = 0; 208 } 209 210 if (getSwitchStack().empty()) { 211 Diag(CaseLoc, diag::err_case_not_in_switch); 212 return StmtError(); 213 } 214 215 // Only now release the smart pointers. 216 lhsval.release(); 217 rhsval.release(); 218 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 219 ColonLoc); 220 getSwitchStack().back()->addSwitchCase(CS); 221 return Owned(CS); 222} 223 224/// ActOnCaseStmtBody - This installs a statement as the body of a case. 225void Sema::ActOnCaseStmtBody(StmtTy *caseStmt, StmtArg subStmt) { 226 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 227 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 228 CS->setSubStmt(SubStmt); 229} 230 231Action::OwningStmtResult 232Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 233 StmtArg subStmt, Scope *CurScope) { 234 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 235 236 if (getSwitchStack().empty()) { 237 Diag(DefaultLoc, diag::err_default_not_in_switch); 238 return Owned(SubStmt); 239 } 240 241 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 242 getSwitchStack().back()->addSwitchCase(DS); 243 return Owned(DS); 244} 245 246Action::OwningStmtResult 247Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 248 SourceLocation ColonLoc, StmtArg subStmt) { 249 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 250 // Look up the record for this label identifier. 251 LabelStmt *&LabelDecl = getLabelMap()[II]; 252 253 // If not forward referenced or defined already, just create a new LabelStmt. 254 if (LabelDecl == 0) 255 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt)); 256 257 assert(LabelDecl->getID() == II && "Label mismatch!"); 258 259 // Otherwise, this label was either forward reference or multiply defined. If 260 // multiply defined, reject it now. 261 if (LabelDecl->getSubStmt()) { 262 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 263 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 264 return Owned(SubStmt); 265 } 266 267 // Otherwise, this label was forward declared, and we just found its real 268 // definition. Fill in the forward definition and return it. 269 LabelDecl->setIdentLoc(IdentLoc); 270 LabelDecl->setSubStmt(SubStmt); 271 return Owned(LabelDecl); 272} 273 274Action::OwningStmtResult 275Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, DeclPtrTy CondVar, 276 StmtArg ThenVal, SourceLocation ElseLoc, 277 StmtArg ElseVal) { 278 OwningExprResult CondResult(CondVal.release()); 279 280 VarDecl *ConditionVar = 0; 281 if (CondVar.get()) { 282 ConditionVar = CondVar.getAs<VarDecl>(); 283 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 284 if (CondResult.isInvalid()) 285 return StmtError(); 286 } 287 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 288 if (!ConditionExpr) 289 return StmtError(); 290 291 Stmt *thenStmt = ThenVal.takeAs<Stmt>(); 292 DiagnoseUnusedExprResult(thenStmt); 293 294 // Warn if the if block has a null body without an else value. 295 // this helps prevent bugs due to typos, such as 296 // if (condition); 297 // do_stuff(); 298 if (!ElseVal.get()) { 299 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 300 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 301 } 302 303 Stmt *elseStmt = ElseVal.takeAs<Stmt>(); 304 DiagnoseUnusedExprResult(elseStmt); 305 306 CondResult.release(); 307 return Owned(new (Context) IfStmt(IfLoc, ConditionVar, ConditionExpr, 308 thenStmt, ElseLoc, elseStmt)); 309} 310 311/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 312/// the specified width and sign. If an overflow occurs, detect it and emit 313/// the specified diagnostic. 314void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 315 unsigned NewWidth, bool NewSign, 316 SourceLocation Loc, 317 unsigned DiagID) { 318 // Perform a conversion to the promoted condition type if needed. 319 if (NewWidth > Val.getBitWidth()) { 320 // If this is an extension, just do it. 321 Val.extend(NewWidth); 322 Val.setIsSigned(NewSign); 323 324 // If the input was signed and negative and the output is 325 // unsigned, don't bother to warn: this is implementation-defined 326 // behavior. 327 // FIXME: Introduce a second, default-ignored warning for this case? 328 } else if (NewWidth < Val.getBitWidth()) { 329 // If this is a truncation, check for overflow. 330 llvm::APSInt ConvVal(Val); 331 ConvVal.trunc(NewWidth); 332 ConvVal.setIsSigned(NewSign); 333 ConvVal.extend(Val.getBitWidth()); 334 ConvVal.setIsSigned(Val.isSigned()); 335 if (ConvVal != Val) 336 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 337 338 // Regardless of whether a diagnostic was emitted, really do the 339 // truncation. 340 Val.trunc(NewWidth); 341 Val.setIsSigned(NewSign); 342 } else if (NewSign != Val.isSigned()) { 343 // Convert the sign to match the sign of the condition. This can cause 344 // overflow as well: unsigned(INTMIN) 345 // We don't diagnose this overflow, because it is implementation-defined 346 // behavior. 347 // FIXME: Introduce a second, default-ignored warning for this case? 348 llvm::APSInt OldVal(Val); 349 Val.setIsSigned(NewSign); 350 } 351} 352 353namespace { 354 struct CaseCompareFunctor { 355 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 356 const llvm::APSInt &RHS) { 357 return LHS.first < RHS; 358 } 359 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 360 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 361 return LHS.first < RHS.first; 362 } 363 bool operator()(const llvm::APSInt &LHS, 364 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 365 return LHS < RHS.first; 366 } 367 }; 368} 369 370/// CmpCaseVals - Comparison predicate for sorting case values. 371/// 372static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 373 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 374 if (lhs.first < rhs.first) 375 return true; 376 377 if (lhs.first == rhs.first && 378 lhs.second->getCaseLoc().getRawEncoding() 379 < rhs.second->getCaseLoc().getRawEncoding()) 380 return true; 381 return false; 382} 383 384/// CmpEnumVals - Comparison predicate for sorting enumeration values. 385/// 386static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 387 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 388{ 389 return lhs.first < rhs.first; 390} 391 392/// EqEnumVals - Comparison preficate for uniqing enumeration values. 393/// 394static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 395 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 396{ 397 return lhs.first == rhs.first; 398} 399 400/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 401/// potentially integral-promoted expression @p expr. 402static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 403 const ImplicitCastExpr *ImplicitCast = 404 dyn_cast_or_null<ImplicitCastExpr>(expr); 405 if (ImplicitCast != NULL) { 406 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 407 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 408 if (TypeBeforePromotion->isIntegralType()) { 409 return TypeBeforePromotion; 410 } 411 } 412 return expr->getType(); 413} 414 415/// \brief Check (and possibly convert) the condition in a switch 416/// statement in C++. 417static bool CheckCXXSwitchCondition(Sema &S, SourceLocation SwitchLoc, 418 Expr *&CondExpr) { 419 if (CondExpr->isTypeDependent()) 420 return false; 421 422 QualType CondType = CondExpr->getType(); 423 424 // C++ 6.4.2.p2: 425 // The condition shall be of integral type, enumeration type, or of a class 426 // type for which a single conversion function to integral or enumeration 427 // type exists (12.3). If the condition is of class type, the condition is 428 // converted by calling that conversion function, and the result of the 429 // conversion is used in place of the original condition for the remainder 430 // of this section. Integral promotions are performed. 431 432 // Make sure that the condition expression has a complete type, 433 // otherwise we'll never find any conversions. 434 if (S.RequireCompleteType(SwitchLoc, CondType, 435 S.PDiag(diag::err_switch_incomplete_class_type) 436 << CondExpr->getSourceRange())) 437 return true; 438 439 UnresolvedSet<4> ViableConversions; 440 UnresolvedSet<4> ExplicitConversions; 441 if (const RecordType *RecordTy = CondType->getAs<RecordType>()) { 442 const UnresolvedSetImpl *Conversions 443 = cast<CXXRecordDecl>(RecordTy->getDecl()) 444 ->getVisibleConversionFunctions(); 445 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 446 E = Conversions->end(); I != E; ++I) { 447 if (CXXConversionDecl *Conversion 448 = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) 449 if (Conversion->getConversionType().getNonReferenceType() 450 ->isIntegralType()) { 451 if (Conversion->isExplicit()) 452 ExplicitConversions.addDecl(I.getDecl(), I.getAccess()); 453 else 454 ViableConversions.addDecl(I.getDecl(), I.getAccess()); 455 } 456 } 457 458 switch (ViableConversions.size()) { 459 case 0: 460 if (ExplicitConversions.size() == 1) { 461 DeclAccessPair Found = ExplicitConversions[0]; 462 CXXConversionDecl *Conversion = 463 cast<CXXConversionDecl>(Found->getUnderlyingDecl()); 464 // The user probably meant to invoke the given explicit 465 // conversion; use it. 466 QualType ConvTy 467 = Conversion->getConversionType().getNonReferenceType(); 468 std::string TypeStr; 469 ConvTy.getAsStringInternal(TypeStr, S.Context.PrintingPolicy); 470 471 S.Diag(SwitchLoc, diag::err_switch_explicit_conversion) 472 << CondType << ConvTy << CondExpr->getSourceRange() 473 << FixItHint::CreateInsertion(CondExpr->getLocStart(), 474 "static_cast<" + TypeStr + ">(") 475 << FixItHint::CreateInsertion( 476 S.PP.getLocForEndOfToken(CondExpr->getLocEnd()), 477 ")"); 478 S.Diag(Conversion->getLocation(), diag::note_switch_conversion) 479 << ConvTy->isEnumeralType() << ConvTy; 480 481 // If we aren't in a SFINAE context, build a call to the 482 // explicit conversion function. 483 if (S.isSFINAEContext()) 484 return true; 485 486 S.CheckMemberOperatorAccess(CondExpr->getExprLoc(), 487 CondExpr, 0, Found); 488 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, Conversion); 489 } 490 491 // We'll complain below about a non-integral condition type. 492 break; 493 494 case 1: { 495 // Apply this conversion. 496 DeclAccessPair Found = ViableConversions[0]; 497 S.CheckMemberOperatorAccess(CondExpr->getExprLoc(), 498 CondExpr, 0, Found); 499 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, 500 cast<CXXConversionDecl>(Found->getUnderlyingDecl())); 501 break; 502 } 503 504 default: 505 S.Diag(SwitchLoc, diag::err_switch_multiple_conversions) 506 << CondType << CondExpr->getSourceRange(); 507 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { 508 CXXConversionDecl *Conv 509 = cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl()); 510 QualType ConvTy = Conv->getConversionType().getNonReferenceType(); 511 S.Diag(Conv->getLocation(), diag::note_switch_conversion) 512 << ConvTy->isEnumeralType() << ConvTy; 513 } 514 return true; 515 } 516 } 517 518 return false; 519} 520 521Action::OwningStmtResult 522Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, ExprArg Cond, 523 DeclPtrTy CondVar) { 524 VarDecl *ConditionVar = 0; 525 if (CondVar.get()) { 526 ConditionVar = CondVar.getAs<VarDecl>(); 527 OwningExprResult CondE = CheckConditionVariable(ConditionVar, SourceLocation(), false); 528 if (CondE.isInvalid()) 529 return StmtError(); 530 531 Cond = move(CondE); 532 } 533 534 Expr *CondExpr = Cond.takeAs<Expr>(); 535 if (!CondExpr) 536 return StmtError(); 537 538 if (getLangOptions().CPlusPlus && 539 CheckCXXSwitchCondition(*this, SwitchLoc, CondExpr)) 540 return StmtError(); 541 542 if (!CondVar.get()) { 543 CondExpr = MaybeCreateCXXExprWithTemporaries(CondExpr); 544 if (!CondExpr) 545 return StmtError(); 546 } 547 548 SwitchStmt *SS = new (Context) SwitchStmt(ConditionVar, CondExpr); 549 getSwitchStack().push_back(SS); 550 return Owned(SS); 551} 552 553Action::OwningStmtResult 554Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch, 555 StmtArg Body) { 556 Stmt *BodyStmt = Body.takeAs<Stmt>(); 557 558 SwitchStmt *SS = getSwitchStack().back(); 559 assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!"); 560 561 SS->setBody(BodyStmt, SwitchLoc); 562 getSwitchStack().pop_back(); 563 564 if (SS->getCond() == 0) { 565 SS->Destroy(Context); 566 return StmtError(); 567 } 568 569 Expr *CondExpr = SS->getCond(); 570 QualType CondTypeBeforePromotion = 571 GetTypeBeforeIntegralPromotion(CondExpr); 572 573 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 574 UsualUnaryConversions(CondExpr); 575 QualType CondType = CondExpr->getType(); 576 SS->setCond(CondExpr); 577 578 // C++ 6.4.2.p2: 579 // Integral promotions are performed (on the switch condition). 580 // 581 // A case value unrepresentable by the original switch condition 582 // type (before the promotion) doesn't make sense, even when it can 583 // be represented by the promoted type. Therefore we need to find 584 // the pre-promotion type of the switch condition. 585 if (!CondExpr->isTypeDependent()) { 586 if (!CondType->isIntegerType()) { // C99 6.8.4.2p1 587 Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer) 588 << CondType << CondExpr->getSourceRange(); 589 return StmtError(); 590 } 591 592 if (CondExpr->isKnownToHaveBooleanValue()) { 593 // switch(bool_expr) {...} is often a programmer error, e.g. 594 // switch(n && mask) { ... } // Doh - should be "n & mask". 595 // One can always use an if statement instead of switch(bool_expr). 596 Diag(SwitchLoc, diag::warn_bool_switch_condition) 597 << CondExpr->getSourceRange(); 598 } 599 } 600 601 // Get the bitwidth of the switched-on value before promotions. We must 602 // convert the integer case values to this width before comparison. 603 bool HasDependentValue 604 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 605 unsigned CondWidth 606 = HasDependentValue? 0 607 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 608 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 609 610 // Accumulate all of the case values in a vector so that we can sort them 611 // and detect duplicates. This vector contains the APInt for the case after 612 // it has been converted to the condition type. 613 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 614 CaseValsTy CaseVals; 615 616 // Keep track of any GNU case ranges we see. The APSInt is the low value. 617 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 618 CaseRangesTy CaseRanges; 619 620 DefaultStmt *TheDefaultStmt = 0; 621 622 bool CaseListIsErroneous = false; 623 624 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 625 SC = SC->getNextSwitchCase()) { 626 627 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 628 if (TheDefaultStmt) { 629 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 630 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 631 632 // FIXME: Remove the default statement from the switch block so that 633 // we'll return a valid AST. This requires recursing down the AST and 634 // finding it, not something we are set up to do right now. For now, 635 // just lop the entire switch stmt out of the AST. 636 CaseListIsErroneous = true; 637 } 638 TheDefaultStmt = DS; 639 640 } else { 641 CaseStmt *CS = cast<CaseStmt>(SC); 642 643 // We already verified that the expression has a i-c-e value (C99 644 // 6.8.4.2p3) - get that value now. 645 Expr *Lo = CS->getLHS(); 646 647 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 648 HasDependentValue = true; 649 break; 650 } 651 652 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 653 654 // Convert the value to the same width/sign as the condition. 655 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 656 CS->getLHS()->getLocStart(), 657 diag::warn_case_value_overflow); 658 659 // If the LHS is not the same type as the condition, insert an implicit 660 // cast. 661 ImpCastExprToType(Lo, CondType, CastExpr::CK_IntegralCast); 662 CS->setLHS(Lo); 663 664 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 665 if (CS->getRHS()) { 666 if (CS->getRHS()->isTypeDependent() || 667 CS->getRHS()->isValueDependent()) { 668 HasDependentValue = true; 669 break; 670 } 671 CaseRanges.push_back(std::make_pair(LoVal, CS)); 672 } else 673 CaseVals.push_back(std::make_pair(LoVal, CS)); 674 } 675 } 676 677 if (!HasDependentValue) { 678 // Sort all the scalar case values so we can easily detect duplicates. 679 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 680 681 if (!CaseVals.empty()) { 682 for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) { 683 if (CaseVals[i].first == CaseVals[i+1].first) { 684 // If we have a duplicate, report it. 685 Diag(CaseVals[i+1].second->getLHS()->getLocStart(), 686 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 687 Diag(CaseVals[i].second->getLHS()->getLocStart(), 688 diag::note_duplicate_case_prev); 689 // FIXME: We really want to remove the bogus case stmt from the 690 // substmt, but we have no way to do this right now. 691 CaseListIsErroneous = true; 692 } 693 } 694 } 695 696 // Detect duplicate case ranges, which usually don't exist at all in 697 // the first place. 698 if (!CaseRanges.empty()) { 699 // Sort all the case ranges by their low value so we can easily detect 700 // overlaps between ranges. 701 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 702 703 // Scan the ranges, computing the high values and removing empty ranges. 704 std::vector<llvm::APSInt> HiVals; 705 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 706 CaseStmt *CR = CaseRanges[i].second; 707 Expr *Hi = CR->getRHS(); 708 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 709 710 // Convert the value to the same width/sign as the condition. 711 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 712 CR->getRHS()->getLocStart(), 713 diag::warn_case_value_overflow); 714 715 // If the LHS is not the same type as the condition, insert an implicit 716 // cast. 717 ImpCastExprToType(Hi, CondType, CastExpr::CK_IntegralCast); 718 CR->setRHS(Hi); 719 720 // If the low value is bigger than the high value, the case is empty. 721 if (CaseRanges[i].first > HiVal) { 722 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 723 << SourceRange(CR->getLHS()->getLocStart(), 724 CR->getRHS()->getLocEnd()); 725 CaseRanges.erase(CaseRanges.begin()+i); 726 --i, --e; 727 continue; 728 } 729 HiVals.push_back(HiVal); 730 } 731 732 // Rescan the ranges, looking for overlap with singleton values and other 733 // ranges. Since the range list is sorted, we only need to compare case 734 // ranges with their neighbors. 735 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 736 llvm::APSInt &CRLo = CaseRanges[i].first; 737 llvm::APSInt &CRHi = HiVals[i]; 738 CaseStmt *CR = CaseRanges[i].second; 739 740 // Check to see whether the case range overlaps with any 741 // singleton cases. 742 CaseStmt *OverlapStmt = 0; 743 llvm::APSInt OverlapVal(32); 744 745 // Find the smallest value >= the lower bound. If I is in the 746 // case range, then we have overlap. 747 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 748 CaseVals.end(), CRLo, 749 CaseCompareFunctor()); 750 if (I != CaseVals.end() && I->first < CRHi) { 751 OverlapVal = I->first; // Found overlap with scalar. 752 OverlapStmt = I->second; 753 } 754 755 // Find the smallest value bigger than the upper bound. 756 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 757 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 758 OverlapVal = (I-1)->first; // Found overlap with scalar. 759 OverlapStmt = (I-1)->second; 760 } 761 762 // Check to see if this case stmt overlaps with the subsequent 763 // case range. 764 if (i && CRLo <= HiVals[i-1]) { 765 OverlapVal = HiVals[i-1]; // Found overlap with range. 766 OverlapStmt = CaseRanges[i-1].second; 767 } 768 769 if (OverlapStmt) { 770 // If we have a duplicate, report it. 771 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 772 << OverlapVal.toString(10); 773 Diag(OverlapStmt->getLHS()->getLocStart(), 774 diag::note_duplicate_case_prev); 775 // FIXME: We really want to remove the bogus case stmt from the 776 // substmt, but we have no way to do this right now. 777 CaseListIsErroneous = true; 778 } 779 } 780 } 781 782 // Check to see if switch is over an Enum and handles all of its 783 // values 784 const EnumType* ET = CondTypeBeforePromotion->getAs<EnumType>(); 785 // If switch has default case, then ignore it. 786 if (!CaseListIsErroneous && !TheDefaultStmt && ET) { 787 const EnumDecl *ED = ET->getDecl(); 788 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 789 EnumValsTy EnumVals; 790 791 // Gather all enum values, set their type and sort them, allowing easier comparison 792 // with CaseVals. 793 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); EDI != ED->enumerator_end(); EDI++) { 794 llvm::APSInt Val = (*EDI)->getInitVal(); 795 if(Val.getBitWidth() < CondWidth) 796 Val.extend(CondWidth); 797 Val.setIsSigned(CondIsSigned); 798 EnumVals.push_back(std::make_pair(Val, (*EDI))); 799 } 800 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 801 EnumValsTy::iterator EIend = std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 802 // See which case values aren't in enum 803 EnumValsTy::const_iterator EI = EnumVals.begin(); 804 for (CaseValsTy::const_iterator CI = CaseVals.begin(); CI != CaseVals.end(); CI++) { 805 while (EI != EIend && EI->first < CI->first) 806 EI++; 807 if (EI == EIend || EI->first > CI->first) 808 Diag(CI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 809 } 810 // See which of case ranges aren't in enum 811 EI = EnumVals.begin(); 812 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); RI != CaseRanges.end() && EI != EIend; RI++) { 813 while (EI != EIend && EI->first < RI->first) 814 EI++; 815 816 if (EI == EIend || EI->first != RI->first) { 817 Diag(RI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 818 } 819 820 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 821 while (EI != EIend && EI->first < Hi) 822 EI++; 823 if (EI == EIend || EI->first != Hi) 824 Diag(RI->second->getRHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 825 } 826 //Check which enum vals aren't in switch 827 CaseValsTy::const_iterator CI = CaseVals.begin(); 828 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 829 EI = EnumVals.begin(); 830 for (; EI != EIend; EI++) { 831 //Drop unneeded case values 832 llvm::APSInt CIVal; 833 while (CI != CaseVals.end() && CI->first < EI->first) 834 CI++; 835 836 if (CI != CaseVals.end() && CI->first == EI->first) 837 continue; 838 839 //Drop unneeded case ranges 840 for (; RI != CaseRanges.end(); RI++) { 841 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 842 if (EI->first <= Hi) 843 break; 844 } 845 846 if (RI == CaseRanges.end() || EI->first < RI->first) 847 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) << EI->second->getDeclName(); 848 } 849 } 850 } 851 852 // FIXME: If the case list was broken is some way, we don't have a good system 853 // to patch it up. Instead, just return the whole substmt as broken. 854 if (CaseListIsErroneous) 855 return StmtError(); 856 857 Switch.release(); 858 return Owned(SS); 859} 860 861Action::OwningStmtResult 862Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 863 DeclPtrTy CondVar, StmtArg Body) { 864 OwningExprResult CondResult(Cond.release()); 865 866 VarDecl *ConditionVar = 0; 867 if (CondVar.get()) { 868 ConditionVar = CondVar.getAs<VarDecl>(); 869 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 870 if (CondResult.isInvalid()) 871 return StmtError(); 872 } 873 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 874 if (!ConditionExpr) 875 return StmtError(); 876 877 Stmt *bodyStmt = Body.takeAs<Stmt>(); 878 DiagnoseUnusedExprResult(bodyStmt); 879 880 CondResult.release(); 881 return Owned(new (Context) WhileStmt(ConditionVar, ConditionExpr, bodyStmt, 882 WhileLoc)); 883} 884 885Action::OwningStmtResult 886Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body, 887 SourceLocation WhileLoc, SourceLocation CondLParen, 888 ExprArg Cond, SourceLocation CondRParen) { 889 Expr *condExpr = Cond.takeAs<Expr>(); 890 assert(condExpr && "ActOnDoStmt(): missing expression"); 891 892 if (CheckBooleanCondition(condExpr, DoLoc)) { 893 Cond = condExpr; 894 return StmtError(); 895 } 896 897 condExpr = MaybeCreateCXXExprWithTemporaries(condExpr); 898 if (!condExpr) 899 return StmtError(); 900 901 Stmt *bodyStmt = Body.takeAs<Stmt>(); 902 DiagnoseUnusedExprResult(bodyStmt); 903 904 Cond.release(); 905 return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc, 906 WhileLoc, CondRParen)); 907} 908 909Action::OwningStmtResult 910Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 911 StmtArg first, FullExprArg second, DeclPtrTy secondVar, 912 FullExprArg third, 913 SourceLocation RParenLoc, StmtArg body) { 914 Stmt *First = static_cast<Stmt*>(first.get()); 915 916 if (!getLangOptions().CPlusPlus) { 917 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 918 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 919 // declare identifiers for objects having storage class 'auto' or 920 // 'register'. 921 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 922 DI!=DE; ++DI) { 923 VarDecl *VD = dyn_cast<VarDecl>(*DI); 924 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 925 VD = 0; 926 if (VD == 0) 927 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 928 // FIXME: mark decl erroneous! 929 } 930 } 931 } 932 933 OwningExprResult SecondResult(second.release()); 934 VarDecl *ConditionVar = 0; 935 if (secondVar.get()) { 936 ConditionVar = secondVar.getAs<VarDecl>(); 937 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 938 if (SecondResult.isInvalid()) 939 return StmtError(); 940 } 941 942 Expr *Third = third.release().takeAs<Expr>(); 943 Stmt *Body = static_cast<Stmt*>(body.get()); 944 945 DiagnoseUnusedExprResult(First); 946 DiagnoseUnusedExprResult(Third); 947 DiagnoseUnusedExprResult(Body); 948 949 first.release(); 950 body.release(); 951 return Owned(new (Context) ForStmt(First, SecondResult.takeAs<Expr>(), 952 ConditionVar, Third, Body, 953 ForLoc, LParenLoc, RParenLoc)); 954} 955 956Action::OwningStmtResult 957Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 958 SourceLocation LParenLoc, 959 StmtArg first, ExprArg second, 960 SourceLocation RParenLoc, StmtArg body) { 961 Stmt *First = static_cast<Stmt*>(first.get()); 962 Expr *Second = static_cast<Expr*>(second.get()); 963 Stmt *Body = static_cast<Stmt*>(body.get()); 964 if (First) { 965 QualType FirstType; 966 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 967 if (!DS->isSingleDecl()) 968 return StmtError(Diag((*DS->decl_begin())->getLocation(), 969 diag::err_toomany_element_decls)); 970 971 Decl *D = DS->getSingleDecl(); 972 FirstType = cast<ValueDecl>(D)->getType(); 973 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 974 // declare identifiers for objects having storage class 'auto' or 975 // 'register'. 976 VarDecl *VD = cast<VarDecl>(D); 977 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 978 return StmtError(Diag(VD->getLocation(), 979 diag::err_non_variable_decl_in_for)); 980 } else { 981 Expr *FirstE = cast<Expr>(First); 982 if (!FirstE->isTypeDependent() && 983 FirstE->isLvalue(Context) != Expr::LV_Valid) 984 return StmtError(Diag(First->getLocStart(), 985 diag::err_selector_element_not_lvalue) 986 << First->getSourceRange()); 987 988 FirstType = static_cast<Expr*>(First)->getType(); 989 } 990 if (!FirstType->isDependentType() && 991 !FirstType->isObjCObjectPointerType() && 992 !FirstType->isBlockPointerType()) 993 Diag(ForLoc, diag::err_selector_element_type) 994 << FirstType << First->getSourceRange(); 995 } 996 if (Second && !Second->isTypeDependent()) { 997 DefaultFunctionArrayLvalueConversion(Second); 998 QualType SecondType = Second->getType(); 999 if (!SecondType->isObjCObjectPointerType()) 1000 Diag(ForLoc, diag::err_collection_expr_type) 1001 << SecondType << Second->getSourceRange(); 1002 } 1003 first.release(); 1004 second.release(); 1005 body.release(); 1006 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1007 ForLoc, RParenLoc)); 1008} 1009 1010Action::OwningStmtResult 1011Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 1012 IdentifierInfo *LabelII) { 1013 // Look up the record for this label identifier. 1014 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 1015 1016 // If we haven't seen this label yet, create a forward reference. 1017 if (LabelDecl == 0) 1018 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 1019 1020 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 1021} 1022 1023Action::OwningStmtResult 1024Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1025 ExprArg DestExp) { 1026 // Convert operand to void* 1027 Expr* E = DestExp.takeAs<Expr>(); 1028 if (!E->isTypeDependent()) { 1029 QualType ETy = E->getType(); 1030 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1031 AssignConvertType ConvTy = 1032 CheckSingleAssignmentConstraints(DestTy, E); 1033 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1034 return StmtError(); 1035 } 1036 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1037} 1038 1039Action::OwningStmtResult 1040Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1041 Scope *S = CurScope->getContinueParent(); 1042 if (!S) { 1043 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1044 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1045 } 1046 1047 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1048} 1049 1050Action::OwningStmtResult 1051Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1052 Scope *S = CurScope->getBreakParent(); 1053 if (!S) { 1054 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1055 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1056 } 1057 1058 return Owned(new (Context) BreakStmt(BreakLoc)); 1059} 1060 1061/// \brief Determine whether a return statement is a candidate for the named 1062/// return value optimization (C++0x 12.8p34, bullet 1). 1063/// 1064/// \param Ctx The context in which the return expression and type occur. 1065/// 1066/// \param RetType The return type of the function or block. 1067/// 1068/// \param RetExpr The expression being returned from the function or block. 1069/// 1070/// \returns The NRVO candidate variable, if the return statement may use the 1071/// NRVO, or NULL if there is no such candidate. 1072static const VarDecl *getNRVOCandidate(ASTContext &Ctx, QualType RetType, 1073 Expr *RetExpr) { 1074 QualType ExprType = RetExpr->getType(); 1075 // - in a return statement in a function with ... 1076 // ... a class return type ... 1077 if (!RetType->isRecordType()) 1078 return 0; 1079 // ... the same cv-unqualified type as the function return type ... 1080 if (!Ctx.hasSameUnqualifiedType(RetType, ExprType)) 1081 return 0; 1082 // ... the expression is the name of a non-volatile automatic object ... 1083 // We ignore parentheses here. 1084 // FIXME: Is this compliant? (Everyone else does it) 1085 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 1086 if (!DR) 1087 return 0; 1088 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1089 if (!VD) 1090 return 0; 1091 1092 if (VD->getKind() == Decl::Var && VD->hasLocalStorage() && 1093 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1094 !VD->getType().isVolatileQualified()) 1095 return VD; 1096 1097 return 0; 1098} 1099 1100/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1101/// 1102Action::OwningStmtResult 1103Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1104 // If this is the first return we've seen in the block, infer the type of 1105 // the block from it. 1106 BlockScopeInfo *CurBlock = getCurBlock(); 1107 if (CurBlock->ReturnType.isNull()) { 1108 if (RetValExp) { 1109 // Don't call UsualUnaryConversions(), since we don't want to do 1110 // integer promotions here. 1111 DefaultFunctionArrayLvalueConversion(RetValExp); 1112 CurBlock->ReturnType = RetValExp->getType(); 1113 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1114 // We have to remove a 'const' added to copied-in variable which was 1115 // part of the implementation spec. and not the actual qualifier for 1116 // the variable. 1117 if (CDRE->isConstQualAdded()) 1118 CurBlock->ReturnType.removeConst(); 1119 } 1120 } else 1121 CurBlock->ReturnType = Context.VoidTy; 1122 } 1123 QualType FnRetType = CurBlock->ReturnType; 1124 1125 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 1126 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1127 << getCurFunctionOrMethodDecl()->getDeclName(); 1128 return StmtError(); 1129 } 1130 1131 // Otherwise, verify that this result type matches the previous one. We are 1132 // pickier with blocks than for normal functions because we don't have GCC 1133 // compatibility to worry about here. 1134 ReturnStmt *Result = 0; 1135 if (CurBlock->ReturnType->isVoidType()) { 1136 if (RetValExp) { 1137 Diag(ReturnLoc, diag::err_return_block_has_expr); 1138 RetValExp->Destroy(Context); 1139 RetValExp = 0; 1140 } 1141 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1142 } else if (!RetValExp) { 1143 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1144 } else { 1145 const VarDecl *NRVOCandidate = 0; 1146 1147 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1148 // we have a non-void block with an expression, continue checking 1149 1150 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1151 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1152 // function return. 1153 1154 // In C++ the return statement is handled via a copy initialization. 1155 // the C version of which boils down to CheckSingleAssignmentConstraints. 1156 NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp); 1157 OwningExprResult Res = PerformCopyInitialization( 1158 InitializedEntity::InitializeResult(ReturnLoc, 1159 FnRetType, 1160 NRVOCandidate != 0), 1161 SourceLocation(), 1162 Owned(RetValExp)); 1163 if (Res.isInvalid()) { 1164 // FIXME: Cleanup temporaries here, anyway? 1165 return StmtError(); 1166 } 1167 1168 if (RetValExp) 1169 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1170 1171 RetValExp = Res.takeAs<Expr>(); 1172 if (RetValExp) 1173 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1174 } 1175 1176 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1177 } 1178 1179 // If we need to check for the named return value optimization, save the 1180 // return statement in our scope for later processing. 1181 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1182 !CurContext->isDependentContext()) 1183 FunctionScopes.back()->Returns.push_back(Result); 1184 1185 return Owned(Result); 1186} 1187 1188Action::OwningStmtResult 1189Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) { 1190 Expr *RetValExp = rex.takeAs<Expr>(); 1191 if (getCurBlock()) 1192 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1193 1194 QualType FnRetType; 1195 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1196 FnRetType = FD->getResultType(); 1197 if (FD->hasAttr<NoReturnAttr>() || 1198 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1199 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1200 << getCurFunctionOrMethodDecl()->getDeclName(); 1201 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1202 FnRetType = MD->getResultType(); 1203 else // If we don't have a function/method context, bail. 1204 return StmtError(); 1205 1206 ReturnStmt *Result = 0; 1207 if (FnRetType->isVoidType()) { 1208 if (RetValExp && !RetValExp->isTypeDependent()) { 1209 // C99 6.8.6.4p1 (ext_ since GCC warns) 1210 unsigned D = diag::ext_return_has_expr; 1211 if (RetValExp->getType()->isVoidType()) 1212 D = diag::ext_return_has_void_expr; 1213 1214 // return (some void expression); is legal in C++. 1215 if (D != diag::ext_return_has_void_expr || 1216 !getLangOptions().CPlusPlus) { 1217 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1218 Diag(ReturnLoc, D) 1219 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1220 << RetValExp->getSourceRange(); 1221 } 1222 1223 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1224 } 1225 1226 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1227 } else if (!RetValExp && !FnRetType->isDependentType()) { 1228 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1229 // C99 6.8.6.4p1 (ext_ since GCC warns) 1230 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1231 1232 if (FunctionDecl *FD = getCurFunctionDecl()) 1233 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1234 else 1235 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1236 Result = new (Context) ReturnStmt(ReturnLoc); 1237 } else { 1238 const VarDecl *NRVOCandidate = 0; 1239 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1240 // we have a non-void function with an expression, continue checking 1241 1242 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1243 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1244 // function return. 1245 1246 // In C++ the return statement is handled via a copy initialization. 1247 // the C version of which boils down to CheckSingleAssignmentConstraints. 1248 NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp); 1249 OwningExprResult Res = PerformCopyInitialization( 1250 InitializedEntity::InitializeResult(ReturnLoc, 1251 FnRetType, 1252 NRVOCandidate != 0), 1253 SourceLocation(), 1254 Owned(RetValExp)); 1255 if (Res.isInvalid()) { 1256 // FIXME: Cleanup temporaries here, anyway? 1257 return StmtError(); 1258 } 1259 1260 RetValExp = Res.takeAs<Expr>(); 1261 if (RetValExp) 1262 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1263 } 1264 1265 if (RetValExp) 1266 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1267 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1268 } 1269 1270 // If we need to check for the named return value optimization, save the 1271 // return statement in our scope for later processing. 1272 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1273 !CurContext->isDependentContext()) 1274 FunctionScopes.back()->Returns.push_back(Result); 1275 1276 return Owned(Result); 1277} 1278 1279/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1280/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1281/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1282/// provide a strong guidance to not use it. 1283/// 1284/// This method checks to see if the argument is an acceptable l-value and 1285/// returns false if it is a case we can handle. 1286static bool CheckAsmLValue(const Expr *E, Sema &S) { 1287 // Type dependent expressions will be checked during instantiation. 1288 if (E->isTypeDependent()) 1289 return false; 1290 1291 if (E->isLvalue(S.Context) == Expr::LV_Valid) 1292 return false; // Cool, this is an lvalue. 1293 1294 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1295 // are supposed to allow. 1296 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1297 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 1298 if (!S.getLangOptions().HeinousExtensions) 1299 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1300 << E->getSourceRange(); 1301 else 1302 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1303 << E->getSourceRange(); 1304 // Accept, even if we emitted an error diagnostic. 1305 return false; 1306 } 1307 1308 // None of the above, just randomly invalid non-lvalue. 1309 return true; 1310} 1311 1312 1313Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1314 bool IsSimple, 1315 bool IsVolatile, 1316 unsigned NumOutputs, 1317 unsigned NumInputs, 1318 IdentifierInfo **Names, 1319 MultiExprArg constraints, 1320 MultiExprArg exprs, 1321 ExprArg asmString, 1322 MultiExprArg clobbers, 1323 SourceLocation RParenLoc, 1324 bool MSAsm) { 1325 unsigned NumClobbers = clobbers.size(); 1326 StringLiteral **Constraints = 1327 reinterpret_cast<StringLiteral**>(constraints.get()); 1328 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 1329 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 1330 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1331 1332 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1333 1334 // The parser verifies that there is a string literal here. 1335 if (AsmString->isWide()) 1336 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1337 << AsmString->getSourceRange()); 1338 1339 for (unsigned i = 0; i != NumOutputs; i++) { 1340 StringLiteral *Literal = Constraints[i]; 1341 if (Literal->isWide()) 1342 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1343 << Literal->getSourceRange()); 1344 1345 llvm::StringRef OutputName; 1346 if (Names[i]) 1347 OutputName = Names[i]->getName(); 1348 1349 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1350 if (!Context.Target.validateOutputConstraint(Info)) 1351 return StmtError(Diag(Literal->getLocStart(), 1352 diag::err_asm_invalid_output_constraint) 1353 << Info.getConstraintStr()); 1354 1355 // Check that the output exprs are valid lvalues. 1356 Expr *OutputExpr = Exprs[i]; 1357 if (CheckAsmLValue(OutputExpr, *this)) { 1358 return StmtError(Diag(OutputExpr->getLocStart(), 1359 diag::err_asm_invalid_lvalue_in_output) 1360 << OutputExpr->getSourceRange()); 1361 } 1362 1363 OutputConstraintInfos.push_back(Info); 1364 } 1365 1366 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1367 1368 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1369 StringLiteral *Literal = Constraints[i]; 1370 if (Literal->isWide()) 1371 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1372 << Literal->getSourceRange()); 1373 1374 llvm::StringRef InputName; 1375 if (Names[i]) 1376 InputName = Names[i]->getName(); 1377 1378 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1379 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1380 NumOutputs, Info)) { 1381 return StmtError(Diag(Literal->getLocStart(), 1382 diag::err_asm_invalid_input_constraint) 1383 << Info.getConstraintStr()); 1384 } 1385 1386 Expr *InputExpr = Exprs[i]; 1387 1388 // Only allow void types for memory constraints. 1389 if (Info.allowsMemory() && !Info.allowsRegister()) { 1390 if (CheckAsmLValue(InputExpr, *this)) 1391 return StmtError(Diag(InputExpr->getLocStart(), 1392 diag::err_asm_invalid_lvalue_in_input) 1393 << Info.getConstraintStr() 1394 << InputExpr->getSourceRange()); 1395 } 1396 1397 if (Info.allowsRegister()) { 1398 if (InputExpr->getType()->isVoidType()) { 1399 return StmtError(Diag(InputExpr->getLocStart(), 1400 diag::err_asm_invalid_type_in_input) 1401 << InputExpr->getType() << Info.getConstraintStr() 1402 << InputExpr->getSourceRange()); 1403 } 1404 } 1405 1406 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1407 1408 InputConstraintInfos.push_back(Info); 1409 } 1410 1411 // Check that the clobbers are valid. 1412 for (unsigned i = 0; i != NumClobbers; i++) { 1413 StringLiteral *Literal = Clobbers[i]; 1414 if (Literal->isWide()) 1415 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1416 << Literal->getSourceRange()); 1417 1418 llvm::StringRef Clobber = Literal->getString(); 1419 1420 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1421 return StmtError(Diag(Literal->getLocStart(), 1422 diag::err_asm_unknown_register_name) << Clobber); 1423 } 1424 1425 constraints.release(); 1426 exprs.release(); 1427 asmString.release(); 1428 clobbers.release(); 1429 AsmStmt *NS = 1430 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1431 NumOutputs, NumInputs, Names, Constraints, Exprs, 1432 AsmString, NumClobbers, Clobbers, RParenLoc); 1433 // Validate the asm string, ensuring it makes sense given the operands we 1434 // have. 1435 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1436 unsigned DiagOffs; 1437 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1438 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1439 << AsmString->getSourceRange(); 1440 DeleteStmt(NS); 1441 return StmtError(); 1442 } 1443 1444 // Validate tied input operands for type mismatches. 1445 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1446 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1447 1448 // If this is a tied constraint, verify that the output and input have 1449 // either exactly the same type, or that they are int/ptr operands with the 1450 // same size (int/long, int*/long, are ok etc). 1451 if (!Info.hasTiedOperand()) continue; 1452 1453 unsigned TiedTo = Info.getTiedOperand(); 1454 Expr *OutputExpr = Exprs[TiedTo]; 1455 Expr *InputExpr = Exprs[i+NumOutputs]; 1456 QualType InTy = InputExpr->getType(); 1457 QualType OutTy = OutputExpr->getType(); 1458 if (Context.hasSameType(InTy, OutTy)) 1459 continue; // All types can be tied to themselves. 1460 1461 // Decide if the input and output are in the same domain (integer/ptr or 1462 // floating point. 1463 enum AsmDomain { 1464 AD_Int, AD_FP, AD_Other 1465 } InputDomain, OutputDomain; 1466 1467 if (InTy->isIntegerType() || InTy->isPointerType()) 1468 InputDomain = AD_Int; 1469 else if (InTy->isFloatingType()) 1470 InputDomain = AD_FP; 1471 else 1472 InputDomain = AD_Other; 1473 1474 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1475 OutputDomain = AD_Int; 1476 else if (OutTy->isFloatingType()) 1477 OutputDomain = AD_FP; 1478 else 1479 OutputDomain = AD_Other; 1480 1481 // They are ok if they are the same size and in the same domain. This 1482 // allows tying things like: 1483 // void* to int* 1484 // void* to int if they are the same size. 1485 // double to long double if they are the same size. 1486 // 1487 uint64_t OutSize = Context.getTypeSize(OutTy); 1488 uint64_t InSize = Context.getTypeSize(InTy); 1489 if (OutSize == InSize && InputDomain == OutputDomain && 1490 InputDomain != AD_Other) 1491 continue; 1492 1493 // If the smaller input/output operand is not mentioned in the asm string, 1494 // then we can promote it and the asm string won't notice. Check this 1495 // case now. 1496 bool SmallerValueMentioned = false; 1497 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1498 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1499 if (!Piece.isOperand()) continue; 1500 1501 // If this is a reference to the input and if the input was the smaller 1502 // one, then we have to reject this asm. 1503 if (Piece.getOperandNo() == i+NumOutputs) { 1504 if (InSize < OutSize) { 1505 SmallerValueMentioned = true; 1506 break; 1507 } 1508 } 1509 1510 // If this is a reference to the input and if the input was the smaller 1511 // one, then we have to reject this asm. 1512 if (Piece.getOperandNo() == TiedTo) { 1513 if (InSize > OutSize) { 1514 SmallerValueMentioned = true; 1515 break; 1516 } 1517 } 1518 } 1519 1520 // If the smaller value wasn't mentioned in the asm string, and if the 1521 // output was a register, just extend the shorter one to the size of the 1522 // larger one. 1523 if (!SmallerValueMentioned && InputDomain != AD_Other && 1524 OutputConstraintInfos[TiedTo].allowsRegister()) 1525 continue; 1526 1527 Diag(InputExpr->getLocStart(), 1528 diag::err_asm_tying_incompatible_types) 1529 << InTy << OutTy << OutputExpr->getSourceRange() 1530 << InputExpr->getSourceRange(); 1531 DeleteStmt(NS); 1532 return StmtError(); 1533 } 1534 1535 return Owned(NS); 1536} 1537 1538Action::OwningStmtResult 1539Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1540 SourceLocation RParen, DeclPtrTy Parm, 1541 StmtArg Body) { 1542 VarDecl *Var = cast_or_null<VarDecl>(Parm.getAs<Decl>()); 1543 if (Var && Var->isInvalidDecl()) 1544 return StmtError(); 1545 1546 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, 1547 Body.takeAs<Stmt>())); 1548} 1549 1550Action::OwningStmtResult 1551Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1552 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1553 static_cast<Stmt*>(Body.release()))); 1554} 1555 1556Action::OwningStmtResult 1557Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, StmtArg Try, 1558 MultiStmtArg CatchStmts, StmtArg Finally) { 1559 FunctionNeedsScopeChecking() = true; 1560 unsigned NumCatchStmts = CatchStmts.size(); 1561 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try.takeAs<Stmt>(), 1562 (Stmt **)CatchStmts.release(), 1563 NumCatchStmts, 1564 Finally.takeAs<Stmt>())); 1565} 1566 1567Sema::OwningStmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 1568 ExprArg ThrowE) { 1569 Expr *Throw = static_cast<Expr *>(ThrowE.get()); 1570 if (Throw) { 1571 QualType ThrowType = Throw->getType(); 1572 // Make sure the expression type is an ObjC pointer or "void *". 1573 if (!ThrowType->isDependentType() && 1574 !ThrowType->isObjCObjectPointerType()) { 1575 const PointerType *PT = ThrowType->getAs<PointerType>(); 1576 if (!PT || !PT->getPointeeType()->isVoidType()) 1577 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1578 << Throw->getType() << Throw->getSourceRange()); 1579 } 1580 } 1581 1582 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowE.takeAs<Expr>())); 1583} 1584 1585Action::OwningStmtResult 1586Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg Throw, 1587 Scope *CurScope) { 1588 if (!Throw.get()) { 1589 // @throw without an expression designates a rethrow (which much occur 1590 // in the context of an @catch clause). 1591 Scope *AtCatchParent = CurScope; 1592 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1593 AtCatchParent = AtCatchParent->getParent(); 1594 if (!AtCatchParent) 1595 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1596 } 1597 1598 return BuildObjCAtThrowStmt(AtLoc, move(Throw)); 1599} 1600 1601Action::OwningStmtResult 1602Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1603 StmtArg SynchBody) { 1604 FunctionNeedsScopeChecking() = true; 1605 1606 // Make sure the expression type is an ObjC pointer or "void *". 1607 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1608 if (!SyncExpr->getType()->isDependentType() && 1609 !SyncExpr->getType()->isObjCObjectPointerType()) { 1610 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1611 if (!PT || !PT->getPointeeType()->isVoidType()) 1612 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1613 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1614 } 1615 1616 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1617 SynchExpr.takeAs<Stmt>(), 1618 SynchBody.takeAs<Stmt>())); 1619} 1620 1621/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1622/// and creates a proper catch handler from them. 1623Action::OwningStmtResult 1624Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1625 StmtArg HandlerBlock) { 1626 // There's nothing to test that ActOnExceptionDecl didn't already test. 1627 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1628 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1629 HandlerBlock.takeAs<Stmt>())); 1630} 1631 1632class TypeWithHandler { 1633 QualType t; 1634 CXXCatchStmt *stmt; 1635public: 1636 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1637 : t(type), stmt(statement) {} 1638 1639 // An arbitrary order is fine as long as it places identical 1640 // types next to each other. 1641 bool operator<(const TypeWithHandler &y) const { 1642 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1643 return true; 1644 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1645 return false; 1646 else 1647 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1648 } 1649 1650 bool operator==(const TypeWithHandler& other) const { 1651 return t == other.t; 1652 } 1653 1654 QualType getQualType() const { return t; } 1655 CXXCatchStmt *getCatchStmt() const { return stmt; } 1656 SourceLocation getTypeSpecStartLoc() const { 1657 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1658 } 1659}; 1660 1661/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1662/// handlers and creates a try statement from them. 1663Action::OwningStmtResult 1664Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1665 MultiStmtArg RawHandlers) { 1666 unsigned NumHandlers = RawHandlers.size(); 1667 assert(NumHandlers > 0 && 1668 "The parser shouldn't call this if there are no handlers."); 1669 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1670 1671 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1672 1673 for (unsigned i = 0; i < NumHandlers; ++i) { 1674 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1675 if (!Handler->getExceptionDecl()) { 1676 if (i < NumHandlers - 1) 1677 return StmtError(Diag(Handler->getLocStart(), 1678 diag::err_early_catch_all)); 1679 1680 continue; 1681 } 1682 1683 const QualType CaughtType = Handler->getCaughtType(); 1684 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1685 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1686 } 1687 1688 // Detect handlers for the same type as an earlier one. 1689 if (NumHandlers > 1) { 1690 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1691 1692 TypeWithHandler prev = TypesWithHandlers[0]; 1693 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1694 TypeWithHandler curr = TypesWithHandlers[i]; 1695 1696 if (curr == prev) { 1697 Diag(curr.getTypeSpecStartLoc(), 1698 diag::warn_exception_caught_by_earlier_handler) 1699 << curr.getCatchStmt()->getCaughtType().getAsString(); 1700 Diag(prev.getTypeSpecStartLoc(), 1701 diag::note_previous_exception_handler) 1702 << prev.getCatchStmt()->getCaughtType().getAsString(); 1703 } 1704 1705 prev = curr; 1706 } 1707 } 1708 1709 // FIXME: We should detect handlers that cannot catch anything because an 1710 // earlier handler catches a superclass. Need to find a method that is not 1711 // quadratic for this. 1712 // Neither of these are explicitly forbidden, but every compiler detects them 1713 // and warns. 1714 1715 FunctionNeedsScopeChecking() = true; 1716 RawHandlers.release(); 1717 return Owned(CXXTryStmt::Create(Context, TryLoc, 1718 static_cast<Stmt*>(TryBlock.release()), 1719 Handlers, NumHandlers)); 1720} 1721