SemaStmt.cpp revision 2b334bb3126a67895813e49e6228dad4aec0b4d6
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); 284 if (CondResult.isInvalid()) 285 return StmtError(); 286 } 287 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 288 if (!ConditionExpr) 289 return StmtError(); 290 291 if (CheckBooleanCondition(ConditionExpr, IfLoc)) { 292 CondResult = ConditionExpr; 293 return StmtError(); 294 } 295 296 Stmt *thenStmt = ThenVal.takeAs<Stmt>(); 297 DiagnoseUnusedExprResult(thenStmt); 298 299 // Warn if the if block has a null body without an else value. 300 // this helps prevent bugs due to typos, such as 301 // if (condition); 302 // do_stuff(); 303 if (!ElseVal.get()) { 304 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 305 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 306 } 307 308 Stmt *elseStmt = ElseVal.takeAs<Stmt>(); 309 DiagnoseUnusedExprResult(elseStmt); 310 311 CondResult.release(); 312 return Owned(new (Context) IfStmt(IfLoc, ConditionVar, ConditionExpr, 313 thenStmt, ElseLoc, elseStmt)); 314} 315 316Action::OwningStmtResult 317Sema::ActOnStartOfSwitchStmt(FullExprArg cond, DeclPtrTy CondVar) { 318 OwningExprResult CondResult(cond.release()); 319 320 VarDecl *ConditionVar = 0; 321 if (CondVar.get()) { 322 ConditionVar = CondVar.getAs<VarDecl>(); 323 CondResult = CheckConditionVariable(ConditionVar); 324 if (CondResult.isInvalid()) 325 return StmtError(); 326 } 327 SwitchStmt *SS = new (Context) SwitchStmt(ConditionVar, 328 CondResult.takeAs<Expr>()); 329 getSwitchStack().push_back(SS); 330 return Owned(SS); 331} 332 333/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 334/// the specified width and sign. If an overflow occurs, detect it and emit 335/// the specified diagnostic. 336void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 337 unsigned NewWidth, bool NewSign, 338 SourceLocation Loc, 339 unsigned DiagID) { 340 // Perform a conversion to the promoted condition type if needed. 341 if (NewWidth > Val.getBitWidth()) { 342 // If this is an extension, just do it. 343 Val.extend(NewWidth); 344 Val.setIsSigned(NewSign); 345 346 // If the input was signed and negative and the output is 347 // unsigned, don't bother to warn: this is implementation-defined 348 // behavior. 349 // FIXME: Introduce a second, default-ignored warning for this case? 350 } else if (NewWidth < Val.getBitWidth()) { 351 // If this is a truncation, check for overflow. 352 llvm::APSInt ConvVal(Val); 353 ConvVal.trunc(NewWidth); 354 ConvVal.setIsSigned(NewSign); 355 ConvVal.extend(Val.getBitWidth()); 356 ConvVal.setIsSigned(Val.isSigned()); 357 if (ConvVal != Val) 358 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 359 360 // Regardless of whether a diagnostic was emitted, really do the 361 // truncation. 362 Val.trunc(NewWidth); 363 Val.setIsSigned(NewSign); 364 } else if (NewSign != Val.isSigned()) { 365 // Convert the sign to match the sign of the condition. This can cause 366 // overflow as well: unsigned(INTMIN) 367 // We don't diagnose this overflow, because it is implementation-defined 368 // behavior. 369 // FIXME: Introduce a second, default-ignored warning for this case? 370 llvm::APSInt OldVal(Val); 371 Val.setIsSigned(NewSign); 372 } 373} 374 375namespace { 376 struct CaseCompareFunctor { 377 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 378 const llvm::APSInt &RHS) { 379 return LHS.first < RHS; 380 } 381 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 382 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 383 return LHS.first < RHS.first; 384 } 385 bool operator()(const llvm::APSInt &LHS, 386 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 387 return LHS < RHS.first; 388 } 389 }; 390} 391 392/// CmpCaseVals - Comparison predicate for sorting case values. 393/// 394static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 395 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 396 if (lhs.first < rhs.first) 397 return true; 398 399 if (lhs.first == rhs.first && 400 lhs.second->getCaseLoc().getRawEncoding() 401 < rhs.second->getCaseLoc().getRawEncoding()) 402 return true; 403 return false; 404} 405 406/// CmpEnumVals - Comparison predicate for sorting enumeration values. 407/// 408static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 409 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 410{ 411 return lhs.first < rhs.first; 412} 413 414/// EqEnumVals - Comparison preficate for uniqing enumeration values. 415/// 416static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 417 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 418{ 419 return lhs.first == rhs.first; 420} 421 422/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 423/// potentially integral-promoted expression @p expr. 424static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 425 const ImplicitCastExpr *ImplicitCast = 426 dyn_cast_or_null<ImplicitCastExpr>(expr); 427 if (ImplicitCast != NULL) { 428 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 429 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 430 if (TypeBeforePromotion->isIntegralType()) { 431 return TypeBeforePromotion; 432 } 433 } 434 return expr->getType(); 435} 436 437/// \brief Check (and possibly convert) the condition in a switch 438/// statement in C++. 439static bool CheckCXXSwitchCondition(Sema &S, SourceLocation SwitchLoc, 440 Expr *&CondExpr) { 441 if (CondExpr->isTypeDependent()) 442 return false; 443 444 QualType CondType = CondExpr->getType(); 445 446 // C++ 6.4.2.p2: 447 // The condition shall be of integral type, enumeration type, or of a class 448 // type for which a single conversion function to integral or enumeration 449 // type exists (12.3). If the condition is of class type, the condition is 450 // converted by calling that conversion function, and the result of the 451 // conversion is used in place of the original condition for the remainder 452 // of this section. Integral promotions are performed. 453 454 // Make sure that the condition expression has a complete type, 455 // otherwise we'll never find any conversions. 456 if (S.RequireCompleteType(SwitchLoc, CondType, 457 S.PDiag(diag::err_switch_incomplete_class_type) 458 << CondExpr->getSourceRange())) 459 return true; 460 461 UnresolvedSet<4> ViableConversions; 462 UnresolvedSet<4> ExplicitConversions; 463 if (const RecordType *RecordTy = CondType->getAs<RecordType>()) { 464 const UnresolvedSetImpl *Conversions 465 = cast<CXXRecordDecl>(RecordTy->getDecl()) 466 ->getVisibleConversionFunctions(); 467 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 468 E = Conversions->end(); I != E; ++I) { 469 if (CXXConversionDecl *Conversion 470 = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) 471 if (Conversion->getConversionType().getNonReferenceType() 472 ->isIntegralType()) { 473 if (Conversion->isExplicit()) 474 ExplicitConversions.addDecl(I.getDecl(), I.getAccess()); 475 else 476 ViableConversions.addDecl(I.getDecl(), I.getAccess()); 477 } 478 } 479 480 switch (ViableConversions.size()) { 481 case 0: 482 if (ExplicitConversions.size() == 1) { 483 DeclAccessPair Found = ExplicitConversions[0]; 484 CXXConversionDecl *Conversion = 485 cast<CXXConversionDecl>(Found->getUnderlyingDecl()); 486 // The user probably meant to invoke the given explicit 487 // conversion; use it. 488 QualType ConvTy 489 = Conversion->getConversionType().getNonReferenceType(); 490 std::string TypeStr; 491 ConvTy.getAsStringInternal(TypeStr, S.Context.PrintingPolicy); 492 493 S.Diag(SwitchLoc, diag::err_switch_explicit_conversion) 494 << CondType << ConvTy << CondExpr->getSourceRange() 495 << FixItHint::CreateInsertion(CondExpr->getLocStart(), 496 "static_cast<" + TypeStr + ">(") 497 << FixItHint::CreateInsertion( 498 S.PP.getLocForEndOfToken(CondExpr->getLocEnd()), 499 ")"); 500 S.Diag(Conversion->getLocation(), diag::note_switch_conversion) 501 << ConvTy->isEnumeralType() << ConvTy; 502 503 // If we aren't in a SFINAE context, build a call to the 504 // explicit conversion function. 505 if (S.isSFINAEContext()) 506 return true; 507 508 S.CheckMemberOperatorAccess(CondExpr->getExprLoc(), 509 CondExpr, 0, Found); 510 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, Conversion); 511 } 512 513 // We'll complain below about a non-integral condition type. 514 break; 515 516 case 1: { 517 // Apply this conversion. 518 DeclAccessPair Found = ViableConversions[0]; 519 S.CheckMemberOperatorAccess(CondExpr->getExprLoc(), 520 CondExpr, 0, Found); 521 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, 522 cast<CXXConversionDecl>(Found->getUnderlyingDecl())); 523 break; 524 } 525 526 default: 527 S.Diag(SwitchLoc, diag::err_switch_multiple_conversions) 528 << CondType << CondExpr->getSourceRange(); 529 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { 530 CXXConversionDecl *Conv 531 = cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl()); 532 QualType ConvTy = Conv->getConversionType().getNonReferenceType(); 533 S.Diag(Conv->getLocation(), diag::note_switch_conversion) 534 << ConvTy->isEnumeralType() << ConvTy; 535 } 536 return true; 537 } 538 } 539 540 return false; 541} 542 543/// ActOnSwitchBodyError - This is called if there is an error parsing the 544/// body of the switch stmt instead of ActOnFinishSwitchStmt. 545void Sema::ActOnSwitchBodyError(SourceLocation SwitchLoc, StmtArg Switch, 546 StmtArg Body) { 547 // Keep the switch stack balanced. 548 assert(getSwitchStack().back() == (SwitchStmt*)Switch.get() && 549 "switch stack missing push/pop!"); 550 getSwitchStack().pop_back(); 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 if (getLangOptions().CPlusPlus && 574 CheckCXXSwitchCondition(*this, SwitchLoc, CondExpr)) 575 return StmtError(); 576 577 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 578 UsualUnaryConversions(CondExpr); 579 QualType CondType = CondExpr->getType(); 580 SS->setCond(CondExpr); 581 582 // C++ 6.4.2.p2: 583 // Integral promotions are performed (on the switch condition). 584 // 585 // A case value unrepresentable by the original switch condition 586 // type (before the promotion) doesn't make sense, even when it can 587 // be represented by the promoted type. Therefore we need to find 588 // the pre-promotion type of the switch condition. 589 if (!CondExpr->isTypeDependent()) { 590 if (!CondType->isIntegerType()) { // C99 6.8.4.2p1 591 Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer) 592 << CondType << CondExpr->getSourceRange(); 593 return StmtError(); 594 } 595 596 if (CondExpr->isKnownToHaveBooleanValue()) { 597 // switch(bool_expr) {...} is often a programmer error, e.g. 598 // switch(n && mask) { ... } // Doh - should be "n & mask". 599 // One can always use an if statement instead of switch(bool_expr). 600 Diag(SwitchLoc, diag::warn_bool_switch_condition) 601 << CondExpr->getSourceRange(); 602 } 603 } 604 605 // Get the bitwidth of the switched-on value before promotions. We must 606 // convert the integer case values to this width before comparison. 607 bool HasDependentValue 608 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 609 unsigned CondWidth 610 = HasDependentValue? 0 611 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 612 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 613 614 // Accumulate all of the case values in a vector so that we can sort them 615 // and detect duplicates. This vector contains the APInt for the case after 616 // it has been converted to the condition type. 617 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 618 CaseValsTy CaseVals; 619 620 // Keep track of any GNU case ranges we see. The APSInt is the low value. 621 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 622 CaseRangesTy CaseRanges; 623 624 DefaultStmt *TheDefaultStmt = 0; 625 626 bool CaseListIsErroneous = false; 627 628 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 629 SC = SC->getNextSwitchCase()) { 630 631 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 632 if (TheDefaultStmt) { 633 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 634 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 635 636 // FIXME: Remove the default statement from the switch block so that 637 // we'll return a valid AST. This requires recursing down the AST and 638 // finding it, not something we are set up to do right now. For now, 639 // just lop the entire switch stmt out of the AST. 640 CaseListIsErroneous = true; 641 } 642 TheDefaultStmt = DS; 643 644 } else { 645 CaseStmt *CS = cast<CaseStmt>(SC); 646 647 // We already verified that the expression has a i-c-e value (C99 648 // 6.8.4.2p3) - get that value now. 649 Expr *Lo = CS->getLHS(); 650 651 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 652 HasDependentValue = true; 653 break; 654 } 655 656 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 657 658 // Convert the value to the same width/sign as the condition. 659 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 660 CS->getLHS()->getLocStart(), 661 diag::warn_case_value_overflow); 662 663 // If the LHS is not the same type as the condition, insert an implicit 664 // cast. 665 ImpCastExprToType(Lo, CondType, CastExpr::CK_IntegralCast); 666 CS->setLHS(Lo); 667 668 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 669 if (CS->getRHS()) { 670 if (CS->getRHS()->isTypeDependent() || 671 CS->getRHS()->isValueDependent()) { 672 HasDependentValue = true; 673 break; 674 } 675 CaseRanges.push_back(std::make_pair(LoVal, CS)); 676 } else 677 CaseVals.push_back(std::make_pair(LoVal, CS)); 678 } 679 } 680 681 if (!HasDependentValue) { 682 // Sort all the scalar case values so we can easily detect duplicates. 683 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 684 685 if (!CaseVals.empty()) { 686 for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) { 687 if (CaseVals[i].first == CaseVals[i+1].first) { 688 // If we have a duplicate, report it. 689 Diag(CaseVals[i+1].second->getLHS()->getLocStart(), 690 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 691 Diag(CaseVals[i].second->getLHS()->getLocStart(), 692 diag::note_duplicate_case_prev); 693 // FIXME: We really want to remove the bogus case stmt from the 694 // substmt, but we have no way to do this right now. 695 CaseListIsErroneous = true; 696 } 697 } 698 } 699 700 // Detect duplicate case ranges, which usually don't exist at all in 701 // the first place. 702 if (!CaseRanges.empty()) { 703 // Sort all the case ranges by their low value so we can easily detect 704 // overlaps between ranges. 705 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 706 707 // Scan the ranges, computing the high values and removing empty ranges. 708 std::vector<llvm::APSInt> HiVals; 709 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 710 CaseStmt *CR = CaseRanges[i].second; 711 Expr *Hi = CR->getRHS(); 712 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 713 714 // Convert the value to the same width/sign as the condition. 715 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 716 CR->getRHS()->getLocStart(), 717 diag::warn_case_value_overflow); 718 719 // If the LHS is not the same type as the condition, insert an implicit 720 // cast. 721 ImpCastExprToType(Hi, CondType, CastExpr::CK_IntegralCast); 722 CR->setRHS(Hi); 723 724 // If the low value is bigger than the high value, the case is empty. 725 if (CaseRanges[i].first > HiVal) { 726 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 727 << SourceRange(CR->getLHS()->getLocStart(), 728 CR->getRHS()->getLocEnd()); 729 CaseRanges.erase(CaseRanges.begin()+i); 730 --i, --e; 731 continue; 732 } 733 HiVals.push_back(HiVal); 734 } 735 736 // Rescan the ranges, looking for overlap with singleton values and other 737 // ranges. Since the range list is sorted, we only need to compare case 738 // ranges with their neighbors. 739 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 740 llvm::APSInt &CRLo = CaseRanges[i].first; 741 llvm::APSInt &CRHi = HiVals[i]; 742 CaseStmt *CR = CaseRanges[i].second; 743 744 // Check to see whether the case range overlaps with any 745 // singleton cases. 746 CaseStmt *OverlapStmt = 0; 747 llvm::APSInt OverlapVal(32); 748 749 // Find the smallest value >= the lower bound. If I is in the 750 // case range, then we have overlap. 751 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 752 CaseVals.end(), CRLo, 753 CaseCompareFunctor()); 754 if (I != CaseVals.end() && I->first < CRHi) { 755 OverlapVal = I->first; // Found overlap with scalar. 756 OverlapStmt = I->second; 757 } 758 759 // Find the smallest value bigger than the upper bound. 760 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 761 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 762 OverlapVal = (I-1)->first; // Found overlap with scalar. 763 OverlapStmt = (I-1)->second; 764 } 765 766 // Check to see if this case stmt overlaps with the subsequent 767 // case range. 768 if (i && CRLo <= HiVals[i-1]) { 769 OverlapVal = HiVals[i-1]; // Found overlap with range. 770 OverlapStmt = CaseRanges[i-1].second; 771 } 772 773 if (OverlapStmt) { 774 // If we have a duplicate, report it. 775 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 776 << OverlapVal.toString(10); 777 Diag(OverlapStmt->getLHS()->getLocStart(), 778 diag::note_duplicate_case_prev); 779 // FIXME: We really want to remove the bogus case stmt from the 780 // substmt, but we have no way to do this right now. 781 CaseListIsErroneous = true; 782 } 783 } 784 } 785 786 // Check to see if switch is over an Enum and handles all of its 787 // values 788 const EnumType* ET = CondTypeBeforePromotion->getAs<EnumType>(); 789 // If switch has default case, then ignore it. 790 if (!CaseListIsErroneous && !TheDefaultStmt && ET) { 791 const EnumDecl *ED = ET->getDecl(); 792 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 793 EnumValsTy EnumVals; 794 795 // Gather all enum values, set their type and sort them, allowing easier comparison 796 // with CaseVals. 797 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); EDI != ED->enumerator_end(); EDI++) { 798 llvm::APSInt Val = (*EDI)->getInitVal(); 799 if(Val.getBitWidth() < CondWidth) 800 Val.extend(CondWidth); 801 Val.setIsSigned(CondIsSigned); 802 EnumVals.push_back(std::make_pair(Val, (*EDI))); 803 } 804 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 805 EnumValsTy::iterator EIend = std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 806 // See which case values aren't in enum 807 EnumValsTy::const_iterator EI = EnumVals.begin(); 808 for (CaseValsTy::const_iterator CI = CaseVals.begin(); CI != CaseVals.end(); CI++) { 809 while (EI != EIend && EI->first < CI->first) 810 EI++; 811 if (EI == EIend || EI->first > CI->first) 812 Diag(CI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 813 } 814 // See which of case ranges aren't in enum 815 EI = EnumVals.begin(); 816 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); RI != CaseRanges.end() && EI != EIend; RI++) { 817 while (EI != EIend && EI->first < RI->first) 818 EI++; 819 820 if (EI == EIend || EI->first != RI->first) { 821 Diag(RI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 822 } 823 824 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 825 while (EI != EIend && EI->first < Hi) 826 EI++; 827 if (EI == EIend || EI->first != Hi) 828 Diag(RI->second->getRHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 829 } 830 //Check which enum vals aren't in switch 831 CaseValsTy::const_iterator CI = CaseVals.begin(); 832 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 833 EI = EnumVals.begin(); 834 for (; EI != EIend; EI++) { 835 //Drop unneeded case values 836 llvm::APSInt CIVal; 837 while (CI != CaseVals.end() && CI->first < EI->first) 838 CI++; 839 840 if (CI != CaseVals.end() && CI->first == EI->first) 841 continue; 842 843 //Drop unneeded case ranges 844 for (; RI != CaseRanges.end(); RI++) { 845 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 846 if (EI->first <= Hi) 847 break; 848 } 849 850 if (RI == CaseRanges.end() || EI->first < RI->first) 851 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) << EI->second->getDeclName(); 852 } 853 } 854 } 855 856 // FIXME: If the case list was broken is some way, we don't have a good system 857 // to patch it up. Instead, just return the whole substmt as broken. 858 if (CaseListIsErroneous) 859 return StmtError(); 860 861 Switch.release(); 862 return Owned(SS); 863} 864 865Action::OwningStmtResult 866Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 867 DeclPtrTy CondVar, StmtArg Body) { 868 OwningExprResult CondResult(Cond.release()); 869 870 VarDecl *ConditionVar = 0; 871 if (CondVar.get()) { 872 ConditionVar = CondVar.getAs<VarDecl>(); 873 CondResult = CheckConditionVariable(ConditionVar); 874 if (CondResult.isInvalid()) 875 return StmtError(); 876 } 877 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 878 if (!ConditionExpr) 879 return StmtError(); 880 881 if (CheckBooleanCondition(ConditionExpr, WhileLoc)) { 882 CondResult = ConditionExpr; 883 return StmtError(); 884 } 885 886 Stmt *bodyStmt = Body.takeAs<Stmt>(); 887 DiagnoseUnusedExprResult(bodyStmt); 888 889 CondResult.release(); 890 return Owned(new (Context) WhileStmt(ConditionVar, ConditionExpr, bodyStmt, 891 WhileLoc)); 892} 893 894Action::OwningStmtResult 895Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body, 896 SourceLocation WhileLoc, SourceLocation CondLParen, 897 ExprArg Cond, SourceLocation CondRParen) { 898 Expr *condExpr = Cond.takeAs<Expr>(); 899 assert(condExpr && "ActOnDoStmt(): missing expression"); 900 901 if (CheckBooleanCondition(condExpr, DoLoc)) { 902 Cond = condExpr; 903 return StmtError(); 904 } 905 906 Stmt *bodyStmt = Body.takeAs<Stmt>(); 907 DiagnoseUnusedExprResult(bodyStmt); 908 909 Cond.release(); 910 return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc, 911 WhileLoc, CondRParen)); 912} 913 914Action::OwningStmtResult 915Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 916 StmtArg first, FullExprArg second, DeclPtrTy secondVar, 917 FullExprArg third, 918 SourceLocation RParenLoc, StmtArg body) { 919 Stmt *First = static_cast<Stmt*>(first.get()); 920 921 if (!getLangOptions().CPlusPlus) { 922 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 923 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 924 // declare identifiers for objects having storage class 'auto' or 925 // 'register'. 926 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 927 DI!=DE; ++DI) { 928 VarDecl *VD = dyn_cast<VarDecl>(*DI); 929 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 930 VD = 0; 931 if (VD == 0) 932 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 933 // FIXME: mark decl erroneous! 934 } 935 } 936 } 937 938 OwningExprResult SecondResult(second.release()); 939 VarDecl *ConditionVar = 0; 940 if (secondVar.get()) { 941 ConditionVar = secondVar.getAs<VarDecl>(); 942 SecondResult = CheckConditionVariable(ConditionVar); 943 if (SecondResult.isInvalid()) 944 return StmtError(); 945 } 946 947 Expr *Second = SecondResult.takeAs<Expr>(); 948 if (Second && CheckBooleanCondition(Second, ForLoc)) { 949 SecondResult = Second; 950 return StmtError(); 951 } 952 953 Expr *Third = third.release().takeAs<Expr>(); 954 Stmt *Body = static_cast<Stmt*>(body.get()); 955 956 DiagnoseUnusedExprResult(First); 957 DiagnoseUnusedExprResult(Third); 958 DiagnoseUnusedExprResult(Body); 959 960 first.release(); 961 body.release(); 962 return Owned(new (Context) ForStmt(First, Second, ConditionVar, Third, Body, 963 ForLoc, LParenLoc, RParenLoc)); 964} 965 966Action::OwningStmtResult 967Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 968 SourceLocation LParenLoc, 969 StmtArg first, ExprArg second, 970 SourceLocation RParenLoc, StmtArg body) { 971 Stmt *First = static_cast<Stmt*>(first.get()); 972 Expr *Second = static_cast<Expr*>(second.get()); 973 Stmt *Body = static_cast<Stmt*>(body.get()); 974 if (First) { 975 QualType FirstType; 976 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 977 if (!DS->isSingleDecl()) 978 return StmtError(Diag((*DS->decl_begin())->getLocation(), 979 diag::err_toomany_element_decls)); 980 981 Decl *D = DS->getSingleDecl(); 982 FirstType = cast<ValueDecl>(D)->getType(); 983 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 984 // declare identifiers for objects having storage class 'auto' or 985 // 'register'. 986 VarDecl *VD = cast<VarDecl>(D); 987 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 988 return StmtError(Diag(VD->getLocation(), 989 diag::err_non_variable_decl_in_for)); 990 } else { 991 if (cast<Expr>(First)->isLvalue(Context) != Expr::LV_Valid) 992 return StmtError(Diag(First->getLocStart(), 993 diag::err_selector_element_not_lvalue) 994 << First->getSourceRange()); 995 996 FirstType = static_cast<Expr*>(First)->getType(); 997 } 998 if (!FirstType->isObjCObjectPointerType() && 999 !FirstType->isBlockPointerType()) 1000 Diag(ForLoc, diag::err_selector_element_type) 1001 << FirstType << First->getSourceRange(); 1002 } 1003 if (Second) { 1004 DefaultFunctionArrayLvalueConversion(Second); 1005 QualType SecondType = Second->getType(); 1006 if (!SecondType->isObjCObjectPointerType()) 1007 Diag(ForLoc, diag::err_collection_expr_type) 1008 << SecondType << Second->getSourceRange(); 1009 } 1010 first.release(); 1011 second.release(); 1012 body.release(); 1013 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1014 ForLoc, RParenLoc)); 1015} 1016 1017Action::OwningStmtResult 1018Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 1019 IdentifierInfo *LabelII) { 1020 // Look up the record for this label identifier. 1021 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 1022 1023 // If we haven't seen this label yet, create a forward reference. 1024 if (LabelDecl == 0) 1025 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 1026 1027 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 1028} 1029 1030Action::OwningStmtResult 1031Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1032 ExprArg DestExp) { 1033 // Convert operand to void* 1034 Expr* E = DestExp.takeAs<Expr>(); 1035 if (!E->isTypeDependent()) { 1036 QualType ETy = E->getType(); 1037 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1038 AssignConvertType ConvTy = 1039 CheckSingleAssignmentConstraints(DestTy, E); 1040 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1041 return StmtError(); 1042 } 1043 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1044} 1045 1046Action::OwningStmtResult 1047Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1048 Scope *S = CurScope->getContinueParent(); 1049 if (!S) { 1050 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1051 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1052 } 1053 1054 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1055} 1056 1057Action::OwningStmtResult 1058Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1059 Scope *S = CurScope->getBreakParent(); 1060 if (!S) { 1061 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1062 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1063 } 1064 1065 return Owned(new (Context) BreakStmt(BreakLoc)); 1066} 1067 1068/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1069/// 1070Action::OwningStmtResult 1071Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1072 // If this is the first return we've seen in the block, infer the type of 1073 // the block from it. 1074 BlockScopeInfo *CurBlock = getCurBlock(); 1075 if (CurBlock->ReturnType.isNull()) { 1076 if (RetValExp) { 1077 // Don't call UsualUnaryConversions(), since we don't want to do 1078 // integer promotions here. 1079 DefaultFunctionArrayLvalueConversion(RetValExp); 1080 CurBlock->ReturnType = RetValExp->getType(); 1081 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1082 // We have to remove a 'const' added to copied-in variable which was 1083 // part of the implementation spec. and not the actual qualifier for 1084 // the variable. 1085 if (CDRE->isConstQualAdded()) 1086 CurBlock->ReturnType.removeConst(); 1087 } 1088 } else 1089 CurBlock->ReturnType = Context.VoidTy; 1090 } 1091 QualType FnRetType = CurBlock->ReturnType; 1092 1093 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 1094 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1095 << getCurFunctionOrMethodDecl()->getDeclName(); 1096 return StmtError(); 1097 } 1098 1099 // Otherwise, verify that this result type matches the previous one. We are 1100 // pickier with blocks than for normal functions because we don't have GCC 1101 // compatibility to worry about here. 1102 if (CurBlock->ReturnType->isVoidType()) { 1103 if (RetValExp) { 1104 Diag(ReturnLoc, diag::err_return_block_has_expr); 1105 RetValExp->Destroy(Context); 1106 RetValExp = 0; 1107 } 1108 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1109 } 1110 1111 if (!RetValExp) 1112 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1113 1114 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1115 // we have a non-void block with an expression, continue checking 1116 1117 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1118 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1119 // function return. 1120 1121 // In C++ the return statement is handled via a copy initialization. 1122 // the C version of which boils down to CheckSingleAssignmentConstraints. 1123 OwningExprResult Res = PerformCopyInitialization( 1124 InitializedEntity::InitializeResult(ReturnLoc, 1125 FnRetType), 1126 SourceLocation(), 1127 Owned(RetValExp)); 1128 if (Res.isInvalid()) { 1129 // FIXME: Cleanup temporaries here, anyway? 1130 return StmtError(); 1131 } 1132 1133 RetValExp = Res.takeAs<Expr>(); 1134 if (RetValExp) 1135 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1136 } 1137 1138 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1139} 1140 1141/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that 1142/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15). 1143static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType, 1144 Expr *RetExpr) { 1145 QualType ExprType = RetExpr->getType(); 1146 // - in a return statement in a function with ... 1147 // ... a class return type ... 1148 if (!RetType->isRecordType()) 1149 return false; 1150 // ... the same cv-unqualified type as the function return type ... 1151 if (!Ctx.hasSameUnqualifiedType(RetType, ExprType)) 1152 return false; 1153 // ... the expression is the name of a non-volatile automatic object ... 1154 // We ignore parentheses here. 1155 // FIXME: Is this compliant? 1156 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 1157 if (!DR) 1158 return false; 1159 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1160 if (!VD) 1161 return false; 1162 return VD->hasLocalStorage() && !VD->getType()->isReferenceType() 1163 && !VD->getType().isVolatileQualified(); 1164} 1165 1166Action::OwningStmtResult 1167Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) { 1168 Expr *RetValExp = rex.takeAs<Expr>(); 1169 if (getCurBlock()) 1170 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1171 1172 QualType FnRetType; 1173 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1174 FnRetType = FD->getResultType(); 1175 if (FD->hasAttr<NoReturnAttr>() || 1176 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1177 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1178 << getCurFunctionOrMethodDecl()->getDeclName(); 1179 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1180 FnRetType = MD->getResultType(); 1181 else // If we don't have a function/method context, bail. 1182 return StmtError(); 1183 1184 if (FnRetType->isVoidType()) { 1185 if (RetValExp && !RetValExp->isTypeDependent()) { 1186 // C99 6.8.6.4p1 (ext_ since GCC warns) 1187 unsigned D = diag::ext_return_has_expr; 1188 if (RetValExp->getType()->isVoidType()) 1189 D = diag::ext_return_has_void_expr; 1190 1191 // return (some void expression); is legal in C++. 1192 if (D != diag::ext_return_has_void_expr || 1193 !getLangOptions().CPlusPlus) { 1194 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1195 Diag(ReturnLoc, D) 1196 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1197 << RetValExp->getSourceRange(); 1198 } 1199 1200 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1201 } 1202 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1203 } 1204 1205 if (!RetValExp && !FnRetType->isDependentType()) { 1206 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1207 // C99 6.8.6.4p1 (ext_ since GCC warns) 1208 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1209 1210 if (FunctionDecl *FD = getCurFunctionDecl()) 1211 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1212 else 1213 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1214 return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0)); 1215 } 1216 1217 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1218 // we have a non-void function with an expression, continue checking 1219 1220 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1221 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1222 // function return. 1223 1224 // C++0x 12.8p15: When certain criteria are met, an implementation is 1225 // allowed to omit the copy construction of a class object, [...] 1226 // - in a return statement in a function with a class return type, when 1227 // the expression is the name of a non-volatile automatic object with 1228 // the same cv-unqualified type as the function return type, the copy 1229 // operation can be omitted [...] 1230 // C++0x 12.8p16: When the criteria for elision of a copy operation are met 1231 // and the object to be copied is designated by an lvalue, overload 1232 // resolution to select the constructor for the copy is first performed 1233 // as if the object were designated by an rvalue. 1234 // Note that we only compute Elidable if we're in C++0x, since we don't 1235 // care otherwise. 1236 bool Elidable = getLangOptions().CPlusPlus0x ? 1237 IsReturnCopyElidable(Context, FnRetType, RetValExp) : 1238 false; 1239 // FIXME: Elidable 1240 (void)Elidable; 1241 1242 // In C++ the return statement is handled via a copy initialization. 1243 // the C version of which boils down to CheckSingleAssignmentConstraints. 1244 OwningExprResult Res = PerformCopyInitialization( 1245 InitializedEntity::InitializeResult(ReturnLoc, 1246 FnRetType), 1247 SourceLocation(), 1248 Owned(RetValExp)); 1249 if (Res.isInvalid()) { 1250 // FIXME: Cleanup temporaries here, anyway? 1251 return StmtError(); 1252 } 1253 1254 RetValExp = Res.takeAs<Expr>(); 1255 if (RetValExp) 1256 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1257 } 1258 1259 if (RetValExp) 1260 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1261 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1262} 1263 1264/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1265/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1266/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1267/// provide a strong guidance to not use it. 1268/// 1269/// This method checks to see if the argument is an acceptable l-value and 1270/// returns false if it is a case we can handle. 1271static bool CheckAsmLValue(const Expr *E, Sema &S) { 1272 // Type dependent expressions will be checked during instantiation. 1273 if (E->isTypeDependent()) 1274 return false; 1275 1276 if (E->isLvalue(S.Context) == Expr::LV_Valid) 1277 return false; // Cool, this is an lvalue. 1278 1279 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1280 // are supposed to allow. 1281 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1282 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 1283 if (!S.getLangOptions().HeinousExtensions) 1284 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1285 << E->getSourceRange(); 1286 else 1287 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1288 << E->getSourceRange(); 1289 // Accept, even if we emitted an error diagnostic. 1290 return false; 1291 } 1292 1293 // None of the above, just randomly invalid non-lvalue. 1294 return true; 1295} 1296 1297 1298Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1299 bool IsSimple, 1300 bool IsVolatile, 1301 unsigned NumOutputs, 1302 unsigned NumInputs, 1303 IdentifierInfo **Names, 1304 MultiExprArg constraints, 1305 MultiExprArg exprs, 1306 ExprArg asmString, 1307 MultiExprArg clobbers, 1308 SourceLocation RParenLoc, 1309 bool MSAsm) { 1310 unsigned NumClobbers = clobbers.size(); 1311 StringLiteral **Constraints = 1312 reinterpret_cast<StringLiteral**>(constraints.get()); 1313 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 1314 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 1315 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1316 1317 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1318 1319 // The parser verifies that there is a string literal here. 1320 if (AsmString->isWide()) 1321 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1322 << AsmString->getSourceRange()); 1323 1324 for (unsigned i = 0; i != NumOutputs; i++) { 1325 StringLiteral *Literal = Constraints[i]; 1326 if (Literal->isWide()) 1327 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1328 << Literal->getSourceRange()); 1329 1330 llvm::StringRef OutputName; 1331 if (Names[i]) 1332 OutputName = Names[i]->getName(); 1333 1334 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1335 if (!Context.Target.validateOutputConstraint(Info)) 1336 return StmtError(Diag(Literal->getLocStart(), 1337 diag::err_asm_invalid_output_constraint) 1338 << Info.getConstraintStr()); 1339 1340 // Check that the output exprs are valid lvalues. 1341 Expr *OutputExpr = Exprs[i]; 1342 if (CheckAsmLValue(OutputExpr, *this)) { 1343 return StmtError(Diag(OutputExpr->getLocStart(), 1344 diag::err_asm_invalid_lvalue_in_output) 1345 << OutputExpr->getSourceRange()); 1346 } 1347 1348 OutputConstraintInfos.push_back(Info); 1349 } 1350 1351 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1352 1353 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1354 StringLiteral *Literal = Constraints[i]; 1355 if (Literal->isWide()) 1356 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1357 << Literal->getSourceRange()); 1358 1359 llvm::StringRef InputName; 1360 if (Names[i]) 1361 InputName = Names[i]->getName(); 1362 1363 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1364 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1365 NumOutputs, Info)) { 1366 return StmtError(Diag(Literal->getLocStart(), 1367 diag::err_asm_invalid_input_constraint) 1368 << Info.getConstraintStr()); 1369 } 1370 1371 Expr *InputExpr = Exprs[i]; 1372 1373 // Only allow void types for memory constraints. 1374 if (Info.allowsMemory() && !Info.allowsRegister()) { 1375 if (CheckAsmLValue(InputExpr, *this)) 1376 return StmtError(Diag(InputExpr->getLocStart(), 1377 diag::err_asm_invalid_lvalue_in_input) 1378 << Info.getConstraintStr() 1379 << InputExpr->getSourceRange()); 1380 } 1381 1382 if (Info.allowsRegister()) { 1383 if (InputExpr->getType()->isVoidType()) { 1384 return StmtError(Diag(InputExpr->getLocStart(), 1385 diag::err_asm_invalid_type_in_input) 1386 << InputExpr->getType() << Info.getConstraintStr() 1387 << InputExpr->getSourceRange()); 1388 } 1389 } 1390 1391 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1392 1393 InputConstraintInfos.push_back(Info); 1394 } 1395 1396 // Check that the clobbers are valid. 1397 for (unsigned i = 0; i != NumClobbers; i++) { 1398 StringLiteral *Literal = Clobbers[i]; 1399 if (Literal->isWide()) 1400 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1401 << Literal->getSourceRange()); 1402 1403 llvm::StringRef Clobber = Literal->getString(); 1404 1405 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1406 return StmtError(Diag(Literal->getLocStart(), 1407 diag::err_asm_unknown_register_name) << Clobber); 1408 } 1409 1410 constraints.release(); 1411 exprs.release(); 1412 asmString.release(); 1413 clobbers.release(); 1414 AsmStmt *NS = 1415 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1416 NumOutputs, NumInputs, Names, Constraints, Exprs, 1417 AsmString, NumClobbers, Clobbers, RParenLoc); 1418 // Validate the asm string, ensuring it makes sense given the operands we 1419 // have. 1420 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1421 unsigned DiagOffs; 1422 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1423 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1424 << AsmString->getSourceRange(); 1425 DeleteStmt(NS); 1426 return StmtError(); 1427 } 1428 1429 // Validate tied input operands for type mismatches. 1430 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1431 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1432 1433 // If this is a tied constraint, verify that the output and input have 1434 // either exactly the same type, or that they are int/ptr operands with the 1435 // same size (int/long, int*/long, are ok etc). 1436 if (!Info.hasTiedOperand()) continue; 1437 1438 unsigned TiedTo = Info.getTiedOperand(); 1439 Expr *OutputExpr = Exprs[TiedTo]; 1440 Expr *InputExpr = Exprs[i+NumOutputs]; 1441 QualType InTy = InputExpr->getType(); 1442 QualType OutTy = OutputExpr->getType(); 1443 if (Context.hasSameType(InTy, OutTy)) 1444 continue; // All types can be tied to themselves. 1445 1446 // Int/ptr operands have some special cases that we allow. 1447 if ((OutTy->isIntegerType() || OutTy->isPointerType()) && 1448 (InTy->isIntegerType() || InTy->isPointerType())) { 1449 1450 // They are ok if they are the same size. Tying void* to int is ok if 1451 // they are the same size, for example. This also allows tying void* to 1452 // int*. 1453 uint64_t OutSize = Context.getTypeSize(OutTy); 1454 uint64_t InSize = Context.getTypeSize(InTy); 1455 if (OutSize == InSize) 1456 continue; 1457 1458 // If the smaller input/output operand is not mentioned in the asm string, 1459 // then we can promote it and the asm string won't notice. Check this 1460 // case now. 1461 bool SmallerValueMentioned = false; 1462 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1463 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1464 if (!Piece.isOperand()) continue; 1465 1466 // If this is a reference to the input and if the input was the smaller 1467 // one, then we have to reject this asm. 1468 if (Piece.getOperandNo() == i+NumOutputs) { 1469 if (InSize < OutSize) { 1470 SmallerValueMentioned = true; 1471 break; 1472 } 1473 } 1474 1475 // If this is a reference to the input and if the input was the smaller 1476 // one, then we have to reject this asm. 1477 if (Piece.getOperandNo() == TiedTo) { 1478 if (InSize > OutSize) { 1479 SmallerValueMentioned = true; 1480 break; 1481 } 1482 } 1483 } 1484 1485 // If the smaller value wasn't mentioned in the asm string, and if the 1486 // output was a register, just extend the shorter one to the size of the 1487 // larger one. 1488 if (!SmallerValueMentioned && 1489 OutputConstraintInfos[TiedTo].allowsRegister()) 1490 continue; 1491 } 1492 1493 Diag(InputExpr->getLocStart(), 1494 diag::err_asm_tying_incompatible_types) 1495 << InTy << OutTy << OutputExpr->getSourceRange() 1496 << InputExpr->getSourceRange(); 1497 DeleteStmt(NS); 1498 return StmtError(); 1499 } 1500 1501 return Owned(NS); 1502} 1503 1504Action::OwningStmtResult 1505Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1506 SourceLocation RParen, DeclPtrTy Parm, 1507 StmtArg Body, StmtArg catchList) { 1508 Stmt *CatchList = catchList.takeAs<Stmt>(); 1509 ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>()); 1510 1511 // PVD == 0 implies @catch(...). 1512 if (PVD) { 1513 // If we already know the decl is invalid, reject it. 1514 if (PVD->isInvalidDecl()) 1515 return StmtError(); 1516 1517 if (!PVD->getType()->isObjCObjectPointerType()) 1518 return StmtError(Diag(PVD->getLocation(), 1519 diag::err_catch_param_not_objc_type)); 1520 if (PVD->getType()->isObjCQualifiedIdType()) 1521 return StmtError(Diag(PVD->getLocation(), 1522 diag::err_illegal_qualifiers_on_catch_parm)); 1523 } 1524 1525 ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen, 1526 PVD, Body.takeAs<Stmt>(), CatchList); 1527 return Owned(CatchList ? CatchList : CS); 1528} 1529 1530Action::OwningStmtResult 1531Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1532 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1533 static_cast<Stmt*>(Body.release()))); 1534} 1535 1536Action::OwningStmtResult 1537Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, 1538 StmtArg Try, StmtArg Catch, StmtArg Finally) { 1539 FunctionNeedsScopeChecking() = true; 1540 return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(), 1541 Catch.takeAs<Stmt>(), 1542 Finally.takeAs<Stmt>())); 1543} 1544 1545Action::OwningStmtResult 1546Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) { 1547 Expr *ThrowExpr = expr.takeAs<Expr>(); 1548 if (!ThrowExpr) { 1549 // @throw without an expression designates a rethrow (which much occur 1550 // in the context of an @catch clause). 1551 Scope *AtCatchParent = CurScope; 1552 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1553 AtCatchParent = AtCatchParent->getParent(); 1554 if (!AtCatchParent) 1555 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1556 } else { 1557 QualType ThrowType = ThrowExpr->getType(); 1558 // Make sure the expression type is an ObjC pointer or "void *". 1559 if (!ThrowType->isObjCObjectPointerType()) { 1560 const PointerType *PT = ThrowType->getAs<PointerType>(); 1561 if (!PT || !PT->getPointeeType()->isVoidType()) 1562 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1563 << ThrowExpr->getType() << ThrowExpr->getSourceRange()); 1564 } 1565 } 1566 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr)); 1567} 1568 1569Action::OwningStmtResult 1570Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1571 StmtArg SynchBody) { 1572 FunctionNeedsScopeChecking() = true; 1573 1574 // Make sure the expression type is an ObjC pointer or "void *". 1575 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1576 if (!SyncExpr->getType()->isObjCObjectPointerType()) { 1577 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1578 if (!PT || !PT->getPointeeType()->isVoidType()) 1579 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1580 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1581 } 1582 1583 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1584 SynchExpr.takeAs<Stmt>(), 1585 SynchBody.takeAs<Stmt>())); 1586} 1587 1588/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1589/// and creates a proper catch handler from them. 1590Action::OwningStmtResult 1591Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1592 StmtArg HandlerBlock) { 1593 // There's nothing to test that ActOnExceptionDecl didn't already test. 1594 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1595 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1596 HandlerBlock.takeAs<Stmt>())); 1597} 1598 1599class TypeWithHandler { 1600 QualType t; 1601 CXXCatchStmt *stmt; 1602public: 1603 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1604 : t(type), stmt(statement) {} 1605 1606 // An arbitrary order is fine as long as it places identical 1607 // types next to each other. 1608 bool operator<(const TypeWithHandler &y) const { 1609 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1610 return true; 1611 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1612 return false; 1613 else 1614 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1615 } 1616 1617 bool operator==(const TypeWithHandler& other) const { 1618 return t == other.t; 1619 } 1620 1621 QualType getQualType() const { return t; } 1622 CXXCatchStmt *getCatchStmt() const { return stmt; } 1623 SourceLocation getTypeSpecStartLoc() const { 1624 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1625 } 1626}; 1627 1628/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1629/// handlers and creates a try statement from them. 1630Action::OwningStmtResult 1631Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1632 MultiStmtArg RawHandlers) { 1633 unsigned NumHandlers = RawHandlers.size(); 1634 assert(NumHandlers > 0 && 1635 "The parser shouldn't call this if there are no handlers."); 1636 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1637 1638 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1639 1640 for (unsigned i = 0; i < NumHandlers; ++i) { 1641 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1642 if (!Handler->getExceptionDecl()) { 1643 if (i < NumHandlers - 1) 1644 return StmtError(Diag(Handler->getLocStart(), 1645 diag::err_early_catch_all)); 1646 1647 continue; 1648 } 1649 1650 const QualType CaughtType = Handler->getCaughtType(); 1651 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1652 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1653 } 1654 1655 // Detect handlers for the same type as an earlier one. 1656 if (NumHandlers > 1) { 1657 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1658 1659 TypeWithHandler prev = TypesWithHandlers[0]; 1660 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1661 TypeWithHandler curr = TypesWithHandlers[i]; 1662 1663 if (curr == prev) { 1664 Diag(curr.getTypeSpecStartLoc(), 1665 diag::warn_exception_caught_by_earlier_handler) 1666 << curr.getCatchStmt()->getCaughtType().getAsString(); 1667 Diag(prev.getTypeSpecStartLoc(), 1668 diag::note_previous_exception_handler) 1669 << prev.getCatchStmt()->getCaughtType().getAsString(); 1670 } 1671 1672 prev = curr; 1673 } 1674 } 1675 1676 // FIXME: We should detect handlers that cannot catch anything because an 1677 // earlier handler catches a superclass. Need to find a method that is not 1678 // quadratic for this. 1679 // Neither of these are explicitly forbidden, but every compiler detects them 1680 // and warns. 1681 1682 FunctionNeedsScopeChecking() = true; 1683 RawHandlers.release(); 1684 return Owned(CXXTryStmt::Create(Context, TryLoc, 1685 static_cast<Stmt*>(TryBlock.release()), 1686 Handlers, NumHandlers)); 1687} 1688