SemaStmt.cpp revision 6907fbe758d23e1aec4c0a67e7b633d1d855feb4
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()->isObjCObjectType()) { 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 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 404 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 405 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 406 if (TypeBeforePromotion->isIntegralType()) { 407 return TypeBeforePromotion; 408 } 409 } 410 return expr->getType(); 411} 412 413/// \brief Check (and possibly convert) the condition in a switch 414/// statement in C++. 415static bool CheckCXXSwitchCondition(Sema &S, SourceLocation SwitchLoc, 416 Expr *&CondExpr) { 417 if (CondExpr->isTypeDependent()) 418 return false; 419 420 QualType CondType = CondExpr->getType(); 421 422 // C++ 6.4.2.p2: 423 // The condition shall be of integral type, enumeration type, or of a class 424 // type for which a single conversion function to integral or enumeration 425 // type exists (12.3). If the condition is of class type, the condition is 426 // converted by calling that conversion function, and the result of the 427 // conversion is used in place of the original condition for the remainder 428 // of this section. Integral promotions are performed. 429 430 // Make sure that the condition expression has a complete type, 431 // otherwise we'll never find any conversions. 432 if (S.RequireCompleteType(SwitchLoc, CondType, 433 S.PDiag(diag::err_switch_incomplete_class_type) 434 << CondExpr->getSourceRange())) 435 return true; 436 437 UnresolvedSet<4> ViableConversions; 438 UnresolvedSet<4> ExplicitConversions; 439 if (const RecordType *RecordTy = CondType->getAs<RecordType>()) { 440 const UnresolvedSetImpl *Conversions 441 = cast<CXXRecordDecl>(RecordTy->getDecl()) 442 ->getVisibleConversionFunctions(); 443 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 444 E = Conversions->end(); I != E; ++I) { 445 if (CXXConversionDecl *Conversion 446 = dyn_cast<CXXConversionDecl>((*I)->getUnderlyingDecl())) 447 if (Conversion->getConversionType().getNonReferenceType() 448 ->isIntegralType()) { 449 if (Conversion->isExplicit()) 450 ExplicitConversions.addDecl(I.getDecl(), I.getAccess()); 451 else 452 ViableConversions.addDecl(I.getDecl(), I.getAccess()); 453 } 454 } 455 456 switch (ViableConversions.size()) { 457 case 0: 458 if (ExplicitConversions.size() == 1) { 459 DeclAccessPair Found = ExplicitConversions[0]; 460 CXXConversionDecl *Conversion = 461 cast<CXXConversionDecl>(Found->getUnderlyingDecl()); 462 // The user probably meant to invoke the given explicit 463 // conversion; use it. 464 QualType ConvTy 465 = Conversion->getConversionType().getNonReferenceType(); 466 std::string TypeStr; 467 ConvTy.getAsStringInternal(TypeStr, S.Context.PrintingPolicy); 468 469 S.Diag(SwitchLoc, diag::err_switch_explicit_conversion) 470 << CondType << ConvTy << CondExpr->getSourceRange() 471 << FixItHint::CreateInsertion(CondExpr->getLocStart(), 472 "static_cast<" + TypeStr + ">(") 473 << FixItHint::CreateInsertion( 474 S.PP.getLocForEndOfToken(CondExpr->getLocEnd()), 475 ")"); 476 S.Diag(Conversion->getLocation(), diag::note_switch_conversion) 477 << ConvTy->isEnumeralType() << ConvTy; 478 479 // If we aren't in a SFINAE context, build a call to the 480 // explicit conversion function. 481 if (S.isSFINAEContext()) 482 return true; 483 484 S.CheckMemberOperatorAccess(CondExpr->getExprLoc(), 485 CondExpr, 0, Found); 486 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, Conversion); 487 } 488 489 // We'll complain below about a non-integral condition type. 490 break; 491 492 case 1: { 493 // Apply this conversion. 494 DeclAccessPair Found = ViableConversions[0]; 495 S.CheckMemberOperatorAccess(CondExpr->getExprLoc(), 496 CondExpr, 0, Found); 497 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, Found, 498 cast<CXXConversionDecl>(Found->getUnderlyingDecl())); 499 break; 500 } 501 502 default: 503 S.Diag(SwitchLoc, diag::err_switch_multiple_conversions) 504 << CondType << CondExpr->getSourceRange(); 505 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { 506 CXXConversionDecl *Conv 507 = cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl()); 508 QualType ConvTy = Conv->getConversionType().getNonReferenceType(); 509 S.Diag(Conv->getLocation(), diag::note_switch_conversion) 510 << ConvTy->isEnumeralType() << ConvTy; 511 } 512 return true; 513 } 514 } 515 516 return false; 517} 518 519Action::OwningStmtResult 520Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, ExprArg Cond, 521 DeclPtrTy CondVar) { 522 VarDecl *ConditionVar = 0; 523 if (CondVar.get()) { 524 ConditionVar = CondVar.getAs<VarDecl>(); 525 OwningExprResult CondE = CheckConditionVariable(ConditionVar, SourceLocation(), false); 526 if (CondE.isInvalid()) 527 return StmtError(); 528 529 Cond = move(CondE); 530 } 531 532 Expr *CondExpr = Cond.takeAs<Expr>(); 533 if (!CondExpr) 534 return StmtError(); 535 536 if (getLangOptions().CPlusPlus && 537 CheckCXXSwitchCondition(*this, SwitchLoc, CondExpr)) 538 return StmtError(); 539 540 if (!CondVar.get()) { 541 CondExpr = MaybeCreateCXXExprWithTemporaries(CondExpr); 542 if (!CondExpr) 543 return StmtError(); 544 } 545 546 SwitchStmt *SS = new (Context) SwitchStmt(ConditionVar, CondExpr); 547 getSwitchStack().push_back(SS); 548 return Owned(SS); 549} 550 551Action::OwningStmtResult 552Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch, 553 StmtArg Body) { 554 Stmt *BodyStmt = Body.takeAs<Stmt>(); 555 556 SwitchStmt *SS = getSwitchStack().back(); 557 assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!"); 558 559 SS->setBody(BodyStmt, SwitchLoc); 560 getSwitchStack().pop_back(); 561 562 if (SS->getCond() == 0) { 563 SS->Destroy(Context); 564 return StmtError(); 565 } 566 567 Expr *CondExpr = SS->getCond(); 568 Expr *CondExprBeforePromotion = CondExpr; 569 QualType CondTypeBeforePromotion = 570 GetTypeBeforeIntegralPromotion(CondExpr); 571 572 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 573 UsualUnaryConversions(CondExpr); 574 QualType CondType = CondExpr->getType(); 575 SS->setCond(CondExpr); 576 577 // C++ 6.4.2.p2: 578 // Integral promotions are performed (on the switch condition). 579 // 580 // A case value unrepresentable by the original switch condition 581 // type (before the promotion) doesn't make sense, even when it can 582 // be represented by the promoted type. Therefore we need to find 583 // the pre-promotion type of the switch condition. 584 if (!CondExpr->isTypeDependent()) { 585 if (!CondType->isIntegerType()) { // C99 6.8.4.2p1 586 Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer) 587 << CondType << CondExpr->getSourceRange(); 588 return StmtError(); 589 } 590 591 if (CondExpr->isKnownToHaveBooleanValue()) { 592 // switch(bool_expr) {...} is often a programmer error, e.g. 593 // switch(n && mask) { ... } // Doh - should be "n & mask". 594 // One can always use an if statement instead of switch(bool_expr). 595 Diag(SwitchLoc, diag::warn_bool_switch_condition) 596 << CondExpr->getSourceRange(); 597 } 598 } 599 600 // Get the bitwidth of the switched-on value before promotions. We must 601 // convert the integer case values to this width before comparison. 602 bool HasDependentValue 603 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 604 unsigned CondWidth 605 = HasDependentValue? 0 606 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 607 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 608 609 // Accumulate all of the case values in a vector so that we can sort them 610 // and detect duplicates. This vector contains the APInt for the case after 611 // it has been converted to the condition type. 612 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 613 CaseValsTy CaseVals; 614 615 // Keep track of any GNU case ranges we see. The APSInt is the low value. 616 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 617 CaseRangesTy CaseRanges; 618 619 DefaultStmt *TheDefaultStmt = 0; 620 621 bool CaseListIsErroneous = false; 622 623 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 624 SC = SC->getNextSwitchCase()) { 625 626 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 627 if (TheDefaultStmt) { 628 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 629 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 630 631 // FIXME: Remove the default statement from the switch block so that 632 // we'll return a valid AST. This requires recursing down the AST and 633 // finding it, not something we are set up to do right now. For now, 634 // just lop the entire switch stmt out of the AST. 635 CaseListIsErroneous = true; 636 } 637 TheDefaultStmt = DS; 638 639 } else { 640 CaseStmt *CS = cast<CaseStmt>(SC); 641 642 // We already verified that the expression has a i-c-e value (C99 643 // 6.8.4.2p3) - get that value now. 644 Expr *Lo = CS->getLHS(); 645 646 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 647 HasDependentValue = true; 648 break; 649 } 650 651 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 652 653 // Convert the value to the same width/sign as the condition. 654 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 655 CS->getLHS()->getLocStart(), 656 diag::warn_case_value_overflow); 657 658 // If the LHS is not the same type as the condition, insert an implicit 659 // cast. 660 ImpCastExprToType(Lo, CondType, CastExpr::CK_IntegralCast); 661 CS->setLHS(Lo); 662 663 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 664 if (CS->getRHS()) { 665 if (CS->getRHS()->isTypeDependent() || 666 CS->getRHS()->isValueDependent()) { 667 HasDependentValue = true; 668 break; 669 } 670 CaseRanges.push_back(std::make_pair(LoVal, CS)); 671 } else 672 CaseVals.push_back(std::make_pair(LoVal, CS)); 673 } 674 } 675 676 if (!HasDependentValue) { 677 // If we don't have a default statement, check whether the 678 // condition is constant. 679 llvm::APSInt ConstantCondValue; 680 bool HasConstantCond = false; 681 bool ShouldCheckConstantCond = false; 682 if (!HasDependentValue && !TheDefaultStmt) { 683 Expr::EvalResult Result; 684 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 685 if (HasConstantCond) { 686 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 687 ConstantCondValue = Result.Val.getInt(); 688 ShouldCheckConstantCond = true; 689 690 assert(ConstantCondValue.getBitWidth() == CondWidth && 691 ConstantCondValue.isSigned() == CondIsSigned); 692 } 693 } 694 695 // Sort all the scalar case values so we can easily detect duplicates. 696 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 697 698 if (!CaseVals.empty()) { 699 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 700 if (ShouldCheckConstantCond && 701 CaseVals[i].first == ConstantCondValue) 702 ShouldCheckConstantCond = false; 703 704 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 705 // If we have a duplicate, report it. 706 Diag(CaseVals[i].second->getLHS()->getLocStart(), 707 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 708 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 709 diag::note_duplicate_case_prev); 710 // FIXME: We really want to remove the bogus case stmt from the 711 // substmt, but we have no way to do this right now. 712 CaseListIsErroneous = true; 713 } 714 } 715 } 716 717 // Detect duplicate case ranges, which usually don't exist at all in 718 // the first place. 719 if (!CaseRanges.empty()) { 720 // Sort all the case ranges by their low value so we can easily detect 721 // overlaps between ranges. 722 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 723 724 // Scan the ranges, computing the high values and removing empty ranges. 725 std::vector<llvm::APSInt> HiVals; 726 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 727 llvm::APSInt &LoVal = CaseRanges[i].first; 728 CaseStmt *CR = CaseRanges[i].second; 729 Expr *Hi = CR->getRHS(); 730 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 731 732 // Convert the value to the same width/sign as the condition. 733 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 734 CR->getRHS()->getLocStart(), 735 diag::warn_case_value_overflow); 736 737 // If the LHS is not the same type as the condition, insert an implicit 738 // cast. 739 ImpCastExprToType(Hi, CondType, CastExpr::CK_IntegralCast); 740 CR->setRHS(Hi); 741 742 // If the low value is bigger than the high value, the case is empty. 743 if (LoVal > HiVal) { 744 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 745 << SourceRange(CR->getLHS()->getLocStart(), 746 CR->getRHS()->getLocEnd()); 747 CaseRanges.erase(CaseRanges.begin()+i); 748 --i, --e; 749 continue; 750 } 751 752 if (ShouldCheckConstantCond && 753 LoVal <= ConstantCondValue && 754 ConstantCondValue <= HiVal) 755 ShouldCheckConstantCond = false; 756 757 HiVals.push_back(HiVal); 758 } 759 760 // Rescan the ranges, looking for overlap with singleton values and other 761 // ranges. Since the range list is sorted, we only need to compare case 762 // ranges with their neighbors. 763 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 764 llvm::APSInt &CRLo = CaseRanges[i].first; 765 llvm::APSInt &CRHi = HiVals[i]; 766 CaseStmt *CR = CaseRanges[i].second; 767 768 // Check to see whether the case range overlaps with any 769 // singleton cases. 770 CaseStmt *OverlapStmt = 0; 771 llvm::APSInt OverlapVal(32); 772 773 // Find the smallest value >= the lower bound. If I is in the 774 // case range, then we have overlap. 775 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 776 CaseVals.end(), CRLo, 777 CaseCompareFunctor()); 778 if (I != CaseVals.end() && I->first < CRHi) { 779 OverlapVal = I->first; // Found overlap with scalar. 780 OverlapStmt = I->second; 781 } 782 783 // Find the smallest value bigger than the upper bound. 784 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 785 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 786 OverlapVal = (I-1)->first; // Found overlap with scalar. 787 OverlapStmt = (I-1)->second; 788 } 789 790 // Check to see if this case stmt overlaps with the subsequent 791 // case range. 792 if (i && CRLo <= HiVals[i-1]) { 793 OverlapVal = HiVals[i-1]; // Found overlap with range. 794 OverlapStmt = CaseRanges[i-1].second; 795 } 796 797 if (OverlapStmt) { 798 // If we have a duplicate, report it. 799 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 800 << OverlapVal.toString(10); 801 Diag(OverlapStmt->getLHS()->getLocStart(), 802 diag::note_duplicate_case_prev); 803 // FIXME: We really want to remove the bogus case stmt from the 804 // substmt, but we have no way to do this right now. 805 CaseListIsErroneous = true; 806 } 807 } 808 } 809 810 // Complain if we have a constant condition and we didn't find a match. 811 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 812 // TODO: it would be nice if we printed enums as enums, chars as 813 // chars, etc. 814 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 815 << ConstantCondValue.toString(10) 816 << CondExpr->getSourceRange(); 817 } 818 819 // Check to see if switch is over an Enum and handles all of its 820 // values. We don't need to do this if there's a default 821 // statement or if we have a constant condition. 822 // 823 // TODO: we might want to check whether case values are out of the 824 // enum even if we don't want to check whether all cases are handled. 825 const EnumType* ET = CondTypeBeforePromotion->getAs<EnumType>(); 826 // If switch has default case, then ignore it. 827 if (!CaseListIsErroneous && !TheDefaultStmt && !HasConstantCond && ET) { 828 const EnumDecl *ED = ET->getDecl(); 829 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 830 EnumValsTy EnumVals; 831 832 // Gather all enum values, set their type and sort them, 833 // allowing easier comparison with CaseVals. 834 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 835 EDI != ED->enumerator_end(); EDI++) { 836 llvm::APSInt Val = (*EDI)->getInitVal(); 837 if(Val.getBitWidth() < CondWidth) 838 Val.extend(CondWidth); 839 Val.setIsSigned(CondIsSigned); 840 EnumVals.push_back(std::make_pair(Val, (*EDI))); 841 } 842 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 843 EnumValsTy::iterator EIend = 844 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 845 // See which case values aren't in enum 846 EnumValsTy::const_iterator EI = EnumVals.begin(); 847 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 848 CI != CaseVals.end(); CI++) { 849 while (EI != EIend && EI->first < CI->first) 850 EI++; 851 if (EI == EIend || EI->first > CI->first) 852 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 853 << ED->getDeclName(); 854 } 855 // See which of case ranges aren't in enum 856 EI = EnumVals.begin(); 857 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 858 RI != CaseRanges.end() && EI != EIend; RI++) { 859 while (EI != EIend && EI->first < RI->first) 860 EI++; 861 862 if (EI == EIend || EI->first != RI->first) { 863 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 864 << ED->getDeclName(); 865 } 866 867 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 868 while (EI != EIend && EI->first < Hi) 869 EI++; 870 if (EI == EIend || EI->first != Hi) 871 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 872 << ED->getDeclName(); 873 } 874 //Check which enum vals aren't in switch 875 CaseValsTy::const_iterator CI = CaseVals.begin(); 876 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 877 EI = EnumVals.begin(); 878 for (; EI != EIend; EI++) { 879 //Drop unneeded case values 880 llvm::APSInt CIVal; 881 while (CI != CaseVals.end() && CI->first < EI->first) 882 CI++; 883 884 if (CI != CaseVals.end() && CI->first == EI->first) 885 continue; 886 887 //Drop unneeded case ranges 888 for (; RI != CaseRanges.end(); RI++) { 889 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 890 if (EI->first <= Hi) 891 break; 892 } 893 894 if (RI == CaseRanges.end() || EI->first < RI->first) 895 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 896 << EI->second->getDeclName(); 897 } 898 } 899 } 900 901 // FIXME: If the case list was broken is some way, we don't have a good system 902 // to patch it up. Instead, just return the whole substmt as broken. 903 if (CaseListIsErroneous) 904 return StmtError(); 905 906 Switch.release(); 907 return Owned(SS); 908} 909 910Action::OwningStmtResult 911Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 912 DeclPtrTy CondVar, StmtArg Body) { 913 OwningExprResult CondResult(Cond.release()); 914 915 VarDecl *ConditionVar = 0; 916 if (CondVar.get()) { 917 ConditionVar = CondVar.getAs<VarDecl>(); 918 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 919 if (CondResult.isInvalid()) 920 return StmtError(); 921 } 922 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 923 if (!ConditionExpr) 924 return StmtError(); 925 926 Stmt *bodyStmt = Body.takeAs<Stmt>(); 927 DiagnoseUnusedExprResult(bodyStmt); 928 929 CondResult.release(); 930 return Owned(new (Context) WhileStmt(ConditionVar, ConditionExpr, bodyStmt, 931 WhileLoc)); 932} 933 934Action::OwningStmtResult 935Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body, 936 SourceLocation WhileLoc, SourceLocation CondLParen, 937 ExprArg Cond, SourceLocation CondRParen) { 938 Expr *condExpr = Cond.takeAs<Expr>(); 939 assert(condExpr && "ActOnDoStmt(): missing expression"); 940 941 if (CheckBooleanCondition(condExpr, DoLoc)) { 942 Cond = condExpr; 943 return StmtError(); 944 } 945 946 condExpr = MaybeCreateCXXExprWithTemporaries(condExpr); 947 if (!condExpr) 948 return StmtError(); 949 950 Stmt *bodyStmt = Body.takeAs<Stmt>(); 951 DiagnoseUnusedExprResult(bodyStmt); 952 953 Cond.release(); 954 return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc, 955 WhileLoc, CondRParen)); 956} 957 958Action::OwningStmtResult 959Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 960 StmtArg first, FullExprArg second, DeclPtrTy secondVar, 961 FullExprArg third, 962 SourceLocation RParenLoc, StmtArg body) { 963 Stmt *First = static_cast<Stmt*>(first.get()); 964 965 if (!getLangOptions().CPlusPlus) { 966 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 967 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 968 // declare identifiers for objects having storage class 'auto' or 969 // 'register'. 970 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 971 DI!=DE; ++DI) { 972 VarDecl *VD = dyn_cast<VarDecl>(*DI); 973 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 974 VD = 0; 975 if (VD == 0) 976 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 977 // FIXME: mark decl erroneous! 978 } 979 } 980 } 981 982 OwningExprResult SecondResult(second.release()); 983 VarDecl *ConditionVar = 0; 984 if (secondVar.get()) { 985 ConditionVar = secondVar.getAs<VarDecl>(); 986 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 987 if (SecondResult.isInvalid()) 988 return StmtError(); 989 } 990 991 Expr *Third = third.release().takeAs<Expr>(); 992 Stmt *Body = static_cast<Stmt*>(body.get()); 993 994 DiagnoseUnusedExprResult(First); 995 DiagnoseUnusedExprResult(Third); 996 DiagnoseUnusedExprResult(Body); 997 998 first.release(); 999 body.release(); 1000 return Owned(new (Context) ForStmt(First, SecondResult.takeAs<Expr>(), 1001 ConditionVar, Third, Body, 1002 ForLoc, LParenLoc, RParenLoc)); 1003} 1004 1005Action::OwningStmtResult 1006Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1007 SourceLocation LParenLoc, 1008 StmtArg first, ExprArg second, 1009 SourceLocation RParenLoc, StmtArg body) { 1010 Stmt *First = static_cast<Stmt*>(first.get()); 1011 Expr *Second = static_cast<Expr*>(second.get()); 1012 Stmt *Body = static_cast<Stmt*>(body.get()); 1013 if (First) { 1014 QualType FirstType; 1015 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1016 if (!DS->isSingleDecl()) 1017 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1018 diag::err_toomany_element_decls)); 1019 1020 Decl *D = DS->getSingleDecl(); 1021 FirstType = cast<ValueDecl>(D)->getType(); 1022 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1023 // declare identifiers for objects having storage class 'auto' or 1024 // 'register'. 1025 VarDecl *VD = cast<VarDecl>(D); 1026 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 1027 return StmtError(Diag(VD->getLocation(), 1028 diag::err_non_variable_decl_in_for)); 1029 } else { 1030 Expr *FirstE = cast<Expr>(First); 1031 if (!FirstE->isTypeDependent() && 1032 FirstE->isLvalue(Context) != Expr::LV_Valid) 1033 return StmtError(Diag(First->getLocStart(), 1034 diag::err_selector_element_not_lvalue) 1035 << First->getSourceRange()); 1036 1037 FirstType = static_cast<Expr*>(First)->getType(); 1038 } 1039 if (!FirstType->isDependentType() && 1040 !FirstType->isObjCObjectPointerType() && 1041 !FirstType->isBlockPointerType()) 1042 Diag(ForLoc, diag::err_selector_element_type) 1043 << FirstType << First->getSourceRange(); 1044 } 1045 if (Second && !Second->isTypeDependent()) { 1046 DefaultFunctionArrayLvalueConversion(Second); 1047 QualType SecondType = Second->getType(); 1048 if (!SecondType->isObjCObjectPointerType()) 1049 Diag(ForLoc, diag::err_collection_expr_type) 1050 << SecondType << Second->getSourceRange(); 1051 } 1052 first.release(); 1053 second.release(); 1054 body.release(); 1055 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1056 ForLoc, RParenLoc)); 1057} 1058 1059Action::OwningStmtResult 1060Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 1061 IdentifierInfo *LabelII) { 1062 // Look up the record for this label identifier. 1063 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 1064 1065 // If we haven't seen this label yet, create a forward reference. 1066 if (LabelDecl == 0) 1067 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 1068 1069 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 1070} 1071 1072Action::OwningStmtResult 1073Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1074 ExprArg DestExp) { 1075 // Convert operand to void* 1076 Expr* E = DestExp.takeAs<Expr>(); 1077 if (!E->isTypeDependent()) { 1078 QualType ETy = E->getType(); 1079 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1080 AssignConvertType ConvTy = 1081 CheckSingleAssignmentConstraints(DestTy, E); 1082 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1083 return StmtError(); 1084 } 1085 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1086} 1087 1088Action::OwningStmtResult 1089Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1090 Scope *S = CurScope->getContinueParent(); 1091 if (!S) { 1092 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1093 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1094 } 1095 1096 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1097} 1098 1099Action::OwningStmtResult 1100Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1101 Scope *S = CurScope->getBreakParent(); 1102 if (!S) { 1103 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1104 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1105 } 1106 1107 return Owned(new (Context) BreakStmt(BreakLoc)); 1108} 1109 1110/// \brief Determine whether a return statement is a candidate for the named 1111/// return value optimization (C++0x 12.8p34, bullet 1). 1112/// 1113/// \param Ctx The context in which the return expression and type occur. 1114/// 1115/// \param RetType The return type of the function or block. 1116/// 1117/// \param RetExpr The expression being returned from the function or block. 1118/// 1119/// \returns The NRVO candidate variable, if the return statement may use the 1120/// NRVO, or NULL if there is no such candidate. 1121static const VarDecl *getNRVOCandidate(ASTContext &Ctx, QualType RetType, 1122 Expr *RetExpr) { 1123 QualType ExprType = RetExpr->getType(); 1124 // - in a return statement in a function with ... 1125 // ... a class return type ... 1126 if (!RetType->isRecordType()) 1127 return 0; 1128 // ... the same cv-unqualified type as the function return type ... 1129 if (!Ctx.hasSameUnqualifiedType(RetType, ExprType)) 1130 return 0; 1131 // ... the expression is the name of a non-volatile automatic object ... 1132 // We ignore parentheses here. 1133 // FIXME: Is this compliant? (Everyone else does it) 1134 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 1135 if (!DR) 1136 return 0; 1137 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1138 if (!VD) 1139 return 0; 1140 1141 if (VD->getKind() == Decl::Var && VD->hasLocalStorage() && 1142 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1143 !VD->getType().isVolatileQualified()) 1144 return VD; 1145 1146 return 0; 1147} 1148 1149/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1150/// 1151Action::OwningStmtResult 1152Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1153 // If this is the first return we've seen in the block, infer the type of 1154 // the block from it. 1155 BlockScopeInfo *CurBlock = getCurBlock(); 1156 if (CurBlock->ReturnType.isNull()) { 1157 if (RetValExp) { 1158 // Don't call UsualUnaryConversions(), since we don't want to do 1159 // integer promotions here. 1160 DefaultFunctionArrayLvalueConversion(RetValExp); 1161 CurBlock->ReturnType = RetValExp->getType(); 1162 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1163 // We have to remove a 'const' added to copied-in variable which was 1164 // part of the implementation spec. and not the actual qualifier for 1165 // the variable. 1166 if (CDRE->isConstQualAdded()) 1167 CurBlock->ReturnType.removeConst(); 1168 } 1169 } else 1170 CurBlock->ReturnType = Context.VoidTy; 1171 } 1172 QualType FnRetType = CurBlock->ReturnType; 1173 1174 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 1175 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1176 << getCurFunctionOrMethodDecl()->getDeclName(); 1177 return StmtError(); 1178 } 1179 1180 // Otherwise, verify that this result type matches the previous one. We are 1181 // pickier with blocks than for normal functions because we don't have GCC 1182 // compatibility to worry about here. 1183 ReturnStmt *Result = 0; 1184 if (CurBlock->ReturnType->isVoidType()) { 1185 if (RetValExp) { 1186 Diag(ReturnLoc, diag::err_return_block_has_expr); 1187 RetValExp->Destroy(Context); 1188 RetValExp = 0; 1189 } 1190 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1191 } else if (!RetValExp) { 1192 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1193 } else { 1194 const VarDecl *NRVOCandidate = 0; 1195 1196 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1197 // we have a non-void block with an expression, continue checking 1198 1199 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1200 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1201 // function return. 1202 1203 // In C++ the return statement is handled via a copy initialization. 1204 // the C version of which boils down to CheckSingleAssignmentConstraints. 1205 NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp); 1206 OwningExprResult Res = PerformCopyInitialization( 1207 InitializedEntity::InitializeResult(ReturnLoc, 1208 FnRetType, 1209 NRVOCandidate != 0), 1210 SourceLocation(), 1211 Owned(RetValExp)); 1212 if (Res.isInvalid()) { 1213 // FIXME: Cleanup temporaries here, anyway? 1214 return StmtError(); 1215 } 1216 1217 if (RetValExp) 1218 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1219 1220 RetValExp = Res.takeAs<Expr>(); 1221 if (RetValExp) 1222 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1223 } 1224 1225 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1226 } 1227 1228 // If we need to check for the named return value optimization, save the 1229 // return statement in our scope for later processing. 1230 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1231 !CurContext->isDependentContext()) 1232 FunctionScopes.back()->Returns.push_back(Result); 1233 1234 return Owned(Result); 1235} 1236 1237Action::OwningStmtResult 1238Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) { 1239 Expr *RetValExp = rex.takeAs<Expr>(); 1240 if (getCurBlock()) 1241 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1242 1243 QualType FnRetType; 1244 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1245 FnRetType = FD->getResultType(); 1246 if (FD->hasAttr<NoReturnAttr>() || 1247 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1248 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1249 << getCurFunctionOrMethodDecl()->getDeclName(); 1250 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1251 FnRetType = MD->getResultType(); 1252 else // If we don't have a function/method context, bail. 1253 return StmtError(); 1254 1255 ReturnStmt *Result = 0; 1256 if (FnRetType->isVoidType()) { 1257 if (RetValExp && !RetValExp->isTypeDependent()) { 1258 // C99 6.8.6.4p1 (ext_ since GCC warns) 1259 unsigned D = diag::ext_return_has_expr; 1260 if (RetValExp->getType()->isVoidType()) 1261 D = diag::ext_return_has_void_expr; 1262 1263 // return (some void expression); is legal in C++. 1264 if (D != diag::ext_return_has_void_expr || 1265 !getLangOptions().CPlusPlus) { 1266 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1267 Diag(ReturnLoc, D) 1268 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1269 << RetValExp->getSourceRange(); 1270 } 1271 1272 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1273 } 1274 1275 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1276 } else if (!RetValExp && !FnRetType->isDependentType()) { 1277 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1278 // C99 6.8.6.4p1 (ext_ since GCC warns) 1279 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1280 1281 if (FunctionDecl *FD = getCurFunctionDecl()) 1282 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1283 else 1284 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1285 Result = new (Context) ReturnStmt(ReturnLoc); 1286 } else { 1287 const VarDecl *NRVOCandidate = 0; 1288 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1289 // we have a non-void function with an expression, continue checking 1290 1291 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1292 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1293 // function return. 1294 1295 // In C++ the return statement is handled via a copy initialization. 1296 // the C version of which boils down to CheckSingleAssignmentConstraints. 1297 NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp); 1298 OwningExprResult Res = PerformCopyInitialization( 1299 InitializedEntity::InitializeResult(ReturnLoc, 1300 FnRetType, 1301 NRVOCandidate != 0), 1302 SourceLocation(), 1303 Owned(RetValExp)); 1304 if (Res.isInvalid()) { 1305 // FIXME: Cleanup temporaries here, anyway? 1306 return StmtError(); 1307 } 1308 1309 RetValExp = Res.takeAs<Expr>(); 1310 if (RetValExp) 1311 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1312 } 1313 1314 if (RetValExp) 1315 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1316 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1317 } 1318 1319 // If we need to check for the named return value optimization, save the 1320 // return statement in our scope for later processing. 1321 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1322 !CurContext->isDependentContext()) 1323 FunctionScopes.back()->Returns.push_back(Result); 1324 1325 return Owned(Result); 1326} 1327 1328/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1329/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1330/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1331/// provide a strong guidance to not use it. 1332/// 1333/// This method checks to see if the argument is an acceptable l-value and 1334/// returns false if it is a case we can handle. 1335static bool CheckAsmLValue(const Expr *E, Sema &S) { 1336 // Type dependent expressions will be checked during instantiation. 1337 if (E->isTypeDependent()) 1338 return false; 1339 1340 if (E->isLvalue(S.Context) == Expr::LV_Valid) 1341 return false; // Cool, this is an lvalue. 1342 1343 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1344 // are supposed to allow. 1345 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1346 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 1347 if (!S.getLangOptions().HeinousExtensions) 1348 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1349 << E->getSourceRange(); 1350 else 1351 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1352 << E->getSourceRange(); 1353 // Accept, even if we emitted an error diagnostic. 1354 return false; 1355 } 1356 1357 // None of the above, just randomly invalid non-lvalue. 1358 return true; 1359} 1360 1361 1362Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1363 bool IsSimple, 1364 bool IsVolatile, 1365 unsigned NumOutputs, 1366 unsigned NumInputs, 1367 IdentifierInfo **Names, 1368 MultiExprArg constraints, 1369 MultiExprArg exprs, 1370 ExprArg asmString, 1371 MultiExprArg clobbers, 1372 SourceLocation RParenLoc, 1373 bool MSAsm) { 1374 unsigned NumClobbers = clobbers.size(); 1375 StringLiteral **Constraints = 1376 reinterpret_cast<StringLiteral**>(constraints.get()); 1377 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 1378 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 1379 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1380 1381 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1382 1383 // The parser verifies that there is a string literal here. 1384 if (AsmString->isWide()) 1385 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1386 << AsmString->getSourceRange()); 1387 1388 for (unsigned i = 0; i != NumOutputs; i++) { 1389 StringLiteral *Literal = Constraints[i]; 1390 if (Literal->isWide()) 1391 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1392 << Literal->getSourceRange()); 1393 1394 llvm::StringRef OutputName; 1395 if (Names[i]) 1396 OutputName = Names[i]->getName(); 1397 1398 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1399 if (!Context.Target.validateOutputConstraint(Info)) 1400 return StmtError(Diag(Literal->getLocStart(), 1401 diag::err_asm_invalid_output_constraint) 1402 << Info.getConstraintStr()); 1403 1404 // Check that the output exprs are valid lvalues. 1405 Expr *OutputExpr = Exprs[i]; 1406 if (CheckAsmLValue(OutputExpr, *this)) { 1407 return StmtError(Diag(OutputExpr->getLocStart(), 1408 diag::err_asm_invalid_lvalue_in_output) 1409 << OutputExpr->getSourceRange()); 1410 } 1411 1412 OutputConstraintInfos.push_back(Info); 1413 } 1414 1415 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1416 1417 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1418 StringLiteral *Literal = Constraints[i]; 1419 if (Literal->isWide()) 1420 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1421 << Literal->getSourceRange()); 1422 1423 llvm::StringRef InputName; 1424 if (Names[i]) 1425 InputName = Names[i]->getName(); 1426 1427 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1428 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1429 NumOutputs, Info)) { 1430 return StmtError(Diag(Literal->getLocStart(), 1431 diag::err_asm_invalid_input_constraint) 1432 << Info.getConstraintStr()); 1433 } 1434 1435 Expr *InputExpr = Exprs[i]; 1436 1437 // Only allow void types for memory constraints. 1438 if (Info.allowsMemory() && !Info.allowsRegister()) { 1439 if (CheckAsmLValue(InputExpr, *this)) 1440 return StmtError(Diag(InputExpr->getLocStart(), 1441 diag::err_asm_invalid_lvalue_in_input) 1442 << Info.getConstraintStr() 1443 << InputExpr->getSourceRange()); 1444 } 1445 1446 if (Info.allowsRegister()) { 1447 if (InputExpr->getType()->isVoidType()) { 1448 return StmtError(Diag(InputExpr->getLocStart(), 1449 diag::err_asm_invalid_type_in_input) 1450 << InputExpr->getType() << Info.getConstraintStr() 1451 << InputExpr->getSourceRange()); 1452 } 1453 } 1454 1455 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1456 1457 InputConstraintInfos.push_back(Info); 1458 } 1459 1460 // Check that the clobbers are valid. 1461 for (unsigned i = 0; i != NumClobbers; i++) { 1462 StringLiteral *Literal = Clobbers[i]; 1463 if (Literal->isWide()) 1464 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1465 << Literal->getSourceRange()); 1466 1467 llvm::StringRef Clobber = Literal->getString(); 1468 1469 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1470 return StmtError(Diag(Literal->getLocStart(), 1471 diag::err_asm_unknown_register_name) << Clobber); 1472 } 1473 1474 constraints.release(); 1475 exprs.release(); 1476 asmString.release(); 1477 clobbers.release(); 1478 AsmStmt *NS = 1479 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1480 NumOutputs, NumInputs, Names, Constraints, Exprs, 1481 AsmString, NumClobbers, Clobbers, RParenLoc); 1482 // Validate the asm string, ensuring it makes sense given the operands we 1483 // have. 1484 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1485 unsigned DiagOffs; 1486 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1487 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1488 << AsmString->getSourceRange(); 1489 DeleteStmt(NS); 1490 return StmtError(); 1491 } 1492 1493 // Validate tied input operands for type mismatches. 1494 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1495 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1496 1497 // If this is a tied constraint, verify that the output and input have 1498 // either exactly the same type, or that they are int/ptr operands with the 1499 // same size (int/long, int*/long, are ok etc). 1500 if (!Info.hasTiedOperand()) continue; 1501 1502 unsigned TiedTo = Info.getTiedOperand(); 1503 Expr *OutputExpr = Exprs[TiedTo]; 1504 Expr *InputExpr = Exprs[i+NumOutputs]; 1505 QualType InTy = InputExpr->getType(); 1506 QualType OutTy = OutputExpr->getType(); 1507 if (Context.hasSameType(InTy, OutTy)) 1508 continue; // All types can be tied to themselves. 1509 1510 // Decide if the input and output are in the same domain (integer/ptr or 1511 // floating point. 1512 enum AsmDomain { 1513 AD_Int, AD_FP, AD_Other 1514 } InputDomain, OutputDomain; 1515 1516 if (InTy->isIntegerType() || InTy->isPointerType()) 1517 InputDomain = AD_Int; 1518 else if (InTy->isFloatingType()) 1519 InputDomain = AD_FP; 1520 else 1521 InputDomain = AD_Other; 1522 1523 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1524 OutputDomain = AD_Int; 1525 else if (OutTy->isFloatingType()) 1526 OutputDomain = AD_FP; 1527 else 1528 OutputDomain = AD_Other; 1529 1530 // They are ok if they are the same size and in the same domain. This 1531 // allows tying things like: 1532 // void* to int* 1533 // void* to int if they are the same size. 1534 // double to long double if they are the same size. 1535 // 1536 uint64_t OutSize = Context.getTypeSize(OutTy); 1537 uint64_t InSize = Context.getTypeSize(InTy); 1538 if (OutSize == InSize && InputDomain == OutputDomain && 1539 InputDomain != AD_Other) 1540 continue; 1541 1542 // If the smaller input/output operand is not mentioned in the asm string, 1543 // then we can promote it and the asm string won't notice. Check this 1544 // case now. 1545 bool SmallerValueMentioned = false; 1546 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1547 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1548 if (!Piece.isOperand()) continue; 1549 1550 // If this is a reference to the input and if the input was the smaller 1551 // one, then we have to reject this asm. 1552 if (Piece.getOperandNo() == i+NumOutputs) { 1553 if (InSize < OutSize) { 1554 SmallerValueMentioned = true; 1555 break; 1556 } 1557 } 1558 1559 // If this is a reference to the input and if the input was the smaller 1560 // one, then we have to reject this asm. 1561 if (Piece.getOperandNo() == TiedTo) { 1562 if (InSize > OutSize) { 1563 SmallerValueMentioned = true; 1564 break; 1565 } 1566 } 1567 } 1568 1569 // If the smaller value wasn't mentioned in the asm string, and if the 1570 // output was a register, just extend the shorter one to the size of the 1571 // larger one. 1572 if (!SmallerValueMentioned && InputDomain != AD_Other && 1573 OutputConstraintInfos[TiedTo].allowsRegister()) 1574 continue; 1575 1576 Diag(InputExpr->getLocStart(), 1577 diag::err_asm_tying_incompatible_types) 1578 << InTy << OutTy << OutputExpr->getSourceRange() 1579 << InputExpr->getSourceRange(); 1580 DeleteStmt(NS); 1581 return StmtError(); 1582 } 1583 1584 return Owned(NS); 1585} 1586 1587Action::OwningStmtResult 1588Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1589 SourceLocation RParen, DeclPtrTy Parm, 1590 StmtArg Body) { 1591 VarDecl *Var = cast_or_null<VarDecl>(Parm.getAs<Decl>()); 1592 if (Var && Var->isInvalidDecl()) 1593 return StmtError(); 1594 1595 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, 1596 Body.takeAs<Stmt>())); 1597} 1598 1599Action::OwningStmtResult 1600Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1601 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1602 static_cast<Stmt*>(Body.release()))); 1603} 1604 1605Action::OwningStmtResult 1606Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, StmtArg Try, 1607 MultiStmtArg CatchStmts, StmtArg Finally) { 1608 FunctionNeedsScopeChecking() = true; 1609 unsigned NumCatchStmts = CatchStmts.size(); 1610 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try.takeAs<Stmt>(), 1611 (Stmt **)CatchStmts.release(), 1612 NumCatchStmts, 1613 Finally.takeAs<Stmt>())); 1614} 1615 1616Sema::OwningStmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 1617 ExprArg ThrowE) { 1618 Expr *Throw = static_cast<Expr *>(ThrowE.get()); 1619 if (Throw) { 1620 QualType ThrowType = Throw->getType(); 1621 // Make sure the expression type is an ObjC pointer or "void *". 1622 if (!ThrowType->isDependentType() && 1623 !ThrowType->isObjCObjectPointerType()) { 1624 const PointerType *PT = ThrowType->getAs<PointerType>(); 1625 if (!PT || !PT->getPointeeType()->isVoidType()) 1626 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1627 << Throw->getType() << Throw->getSourceRange()); 1628 } 1629 } 1630 1631 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowE.takeAs<Expr>())); 1632} 1633 1634Action::OwningStmtResult 1635Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg Throw, 1636 Scope *CurScope) { 1637 if (!Throw.get()) { 1638 // @throw without an expression designates a rethrow (which much occur 1639 // in the context of an @catch clause). 1640 Scope *AtCatchParent = CurScope; 1641 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1642 AtCatchParent = AtCatchParent->getParent(); 1643 if (!AtCatchParent) 1644 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1645 } 1646 1647 return BuildObjCAtThrowStmt(AtLoc, move(Throw)); 1648} 1649 1650Action::OwningStmtResult 1651Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1652 StmtArg SynchBody) { 1653 FunctionNeedsScopeChecking() = true; 1654 1655 // Make sure the expression type is an ObjC pointer or "void *". 1656 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1657 if (!SyncExpr->getType()->isDependentType() && 1658 !SyncExpr->getType()->isObjCObjectPointerType()) { 1659 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1660 if (!PT || !PT->getPointeeType()->isVoidType()) 1661 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1662 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1663 } 1664 1665 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1666 SynchExpr.takeAs<Stmt>(), 1667 SynchBody.takeAs<Stmt>())); 1668} 1669 1670/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1671/// and creates a proper catch handler from them. 1672Action::OwningStmtResult 1673Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1674 StmtArg HandlerBlock) { 1675 // There's nothing to test that ActOnExceptionDecl didn't already test. 1676 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1677 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1678 HandlerBlock.takeAs<Stmt>())); 1679} 1680 1681class TypeWithHandler { 1682 QualType t; 1683 CXXCatchStmt *stmt; 1684public: 1685 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1686 : t(type), stmt(statement) {} 1687 1688 // An arbitrary order is fine as long as it places identical 1689 // types next to each other. 1690 bool operator<(const TypeWithHandler &y) const { 1691 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1692 return true; 1693 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1694 return false; 1695 else 1696 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1697 } 1698 1699 bool operator==(const TypeWithHandler& other) const { 1700 return t == other.t; 1701 } 1702 1703 QualType getQualType() const { return t; } 1704 CXXCatchStmt *getCatchStmt() const { return stmt; } 1705 SourceLocation getTypeSpecStartLoc() const { 1706 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1707 } 1708}; 1709 1710/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1711/// handlers and creates a try statement from them. 1712Action::OwningStmtResult 1713Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1714 MultiStmtArg RawHandlers) { 1715 unsigned NumHandlers = RawHandlers.size(); 1716 assert(NumHandlers > 0 && 1717 "The parser shouldn't call this if there are no handlers."); 1718 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1719 1720 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1721 1722 for (unsigned i = 0; i < NumHandlers; ++i) { 1723 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1724 if (!Handler->getExceptionDecl()) { 1725 if (i < NumHandlers - 1) 1726 return StmtError(Diag(Handler->getLocStart(), 1727 diag::err_early_catch_all)); 1728 1729 continue; 1730 } 1731 1732 const QualType CaughtType = Handler->getCaughtType(); 1733 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1734 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1735 } 1736 1737 // Detect handlers for the same type as an earlier one. 1738 if (NumHandlers > 1) { 1739 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1740 1741 TypeWithHandler prev = TypesWithHandlers[0]; 1742 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1743 TypeWithHandler curr = TypesWithHandlers[i]; 1744 1745 if (curr == prev) { 1746 Diag(curr.getTypeSpecStartLoc(), 1747 diag::warn_exception_caught_by_earlier_handler) 1748 << curr.getCatchStmt()->getCaughtType().getAsString(); 1749 Diag(prev.getTypeSpecStartLoc(), 1750 diag::note_previous_exception_handler) 1751 << prev.getCatchStmt()->getCaughtType().getAsString(); 1752 } 1753 1754 prev = curr; 1755 } 1756 } 1757 1758 // FIXME: We should detect handlers that cannot catch anything because an 1759 // earlier handler catches a superclass. Need to find a method that is not 1760 // quadratic for this. 1761 // Neither of these are explicitly forbidden, but every compiler detects them 1762 // and warns. 1763 1764 FunctionNeedsScopeChecking() = true; 1765 RawHandlers.release(); 1766 return Owned(CXXTryStmt::Create(Context, TryLoc, 1767 static_cast<Stmt*>(TryBlock.release()), 1768 Handlers, NumHandlers)); 1769} 1770