SemaStmt.cpp revision b403d6d746239095a2c7bac958c924d92434e2b4
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 "clang/Sema/SemaInternal.h" 15#include "clang/Sema/Scope.h" 16#include "clang/Sema/ScopeInfo.h" 17#include "clang/Sema/Initialization.h" 18#include "clang/Sema/Lookup.h" 19#include "clang/AST/APValue.h" 20#include "clang/AST/ASTContext.h" 21#include "clang/AST/DeclObjC.h" 22#include "clang/AST/ExprCXX.h" 23#include "clang/AST/ExprObjC.h" 24#include "clang/AST/StmtObjC.h" 25#include "clang/AST/StmtCXX.h" 26#include "clang/AST/TypeLoc.h" 27#include "clang/Lex/Preprocessor.h" 28#include "clang/Basic/TargetInfo.h" 29#include "llvm/ADT/ArrayRef.h" 30#include "llvm/ADT/STLExtras.h" 31#include "llvm/ADT/SmallVector.h" 32using namespace clang; 33using namespace sema; 34 35StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 36 Expr *E = expr.get(); 37 if (!E) // FIXME: FullExprArg has no error state? 38 return StmtError(); 39 40 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 41 // void expression for its side effects. Conversion to void allows any 42 // operand, even incomplete types. 43 44 // Same thing in for stmt first clause (when expr) and third clause. 45 return Owned(static_cast<Stmt*>(E)); 46} 47 48 49StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, bool LeadingEmptyMacro) { 50 return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacro)); 51} 52 53StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 54 SourceLocation EndLoc) { 55 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 56 57 // If we have an invalid decl, just return an error. 58 if (DG.isNull()) return StmtError(); 59 60 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 61} 62 63void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 64 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 65 66 // If we have an invalid decl, just return. 67 if (DG.isNull() || !DG.isSingleDecl()) return; 68 // suppress any potential 'unused variable' warning. 69 DG.getSingleDecl()->setUsed(); 70} 71 72void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 73 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 74 return DiagnoseUnusedExprResult(Label->getSubStmt()); 75 76 const Expr *E = dyn_cast_or_null<Expr>(S); 77 if (!E) 78 return; 79 80 if (E->isBoundMemberFunction(Context)) { 81 Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func) 82 << E->getSourceRange(); 83 return; 84 } 85 86 SourceLocation Loc; 87 SourceRange R1, R2; 88 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 89 return; 90 91 // Okay, we have an unused result. Depending on what the base expression is, 92 // we might want to make a more specific diagnostic. Check for one of these 93 // cases now. 94 unsigned DiagID = diag::warn_unused_expr; 95 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 96 E = Temps->getSubExpr(); 97 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 98 E = TempExpr->getSubExpr(); 99 100 E = E->IgnoreParenImpCasts(); 101 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 102 if (E->getType()->isVoidType()) 103 return; 104 105 // If the callee has attribute pure, const, or warn_unused_result, warn with 106 // a more specific message to make it clear what is happening. 107 if (const Decl *FD = CE->getCalleeDecl()) { 108 if (FD->getAttr<WarnUnusedResultAttr>()) { 109 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 110 return; 111 } 112 if (FD->getAttr<PureAttr>()) { 113 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 114 return; 115 } 116 if (FD->getAttr<ConstAttr>()) { 117 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 118 return; 119 } 120 } 121 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 122 const ObjCMethodDecl *MD = ME->getMethodDecl(); 123 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 124 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 125 return; 126 } 127 } else if (isa<ObjCPropertyRefExpr>(E)) { 128 DiagID = diag::warn_unused_property_expr; 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 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 151} 152 153StmtResult 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 188StmtResult 189Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 190 SourceLocation DotDotDotLoc, Expr *RHSVal, 191 SourceLocation ColonLoc) { 192 assert((LHSVal != 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 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 197 VerifyIntegerConstantExpression(LHSVal)) 198 return StmtError(); 199 200 // GCC extension: The expression shall be an integer constant. 201 202 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 203 VerifyIntegerConstantExpression(RHSVal)) { 204 RHSVal = 0; // Recover by just forgetting about it. 205 } 206 207 if (getCurFunction()->SwitchStack.empty()) { 208 Diag(CaseLoc, diag::err_case_not_in_switch); 209 return StmtError(); 210 } 211 212 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 213 ColonLoc); 214 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 215 return Owned(CS); 216} 217 218/// ActOnCaseStmtBody - This installs a statement as the body of a case. 219void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 220 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 221 CS->setSubStmt(SubStmt); 222} 223 224StmtResult 225Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 226 Stmt *SubStmt, Scope *CurScope) { 227 if (getCurFunction()->SwitchStack.empty()) { 228 Diag(DefaultLoc, diag::err_default_not_in_switch); 229 return Owned(SubStmt); 230 } 231 232 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 233 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 234 return Owned(DS); 235} 236 237StmtResult 238Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 239 SourceLocation ColonLoc, Stmt *SubStmt) { 240 241 // If the label was multiply defined, reject it now. 242 if (TheDecl->getStmt()) { 243 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 244 Diag(TheDecl->getLocation(), diag::note_previous_definition); 245 return Owned(SubStmt); 246 } 247 248 // Otherwise, things are good. Fill in the declaration and return it. 249 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 250 TheDecl->setStmt(LS); 251 if (!TheDecl->isGnuLocal()) 252 TheDecl->setLocation(IdentLoc); 253 return Owned(LS); 254} 255 256StmtResult 257Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 258 Stmt *thenStmt, SourceLocation ElseLoc, 259 Stmt *elseStmt) { 260 ExprResult CondResult(CondVal.release()); 261 262 VarDecl *ConditionVar = 0; 263 if (CondVar) { 264 ConditionVar = cast<VarDecl>(CondVar); 265 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 266 if (CondResult.isInvalid()) 267 return StmtError(); 268 } 269 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 270 if (!ConditionExpr) 271 return StmtError(); 272 273 DiagnoseUnusedExprResult(thenStmt); 274 275 // Warn if the if block has a null body without an else value. 276 // this helps prevent bugs due to typos, such as 277 // if (condition); 278 // do_stuff(); 279 // 280 if (!elseStmt) { 281 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 282 // But do not warn if the body is a macro that expands to nothing, e.g: 283 // 284 // #define CALL(x) 285 // if (condition) 286 // CALL(0); 287 // 288 if (!stmt->hasLeadingEmptyMacro()) 289 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 290 } 291 292 DiagnoseUnusedExprResult(elseStmt); 293 294 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 295 thenStmt, ElseLoc, elseStmt)); 296} 297 298/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 299/// the specified width and sign. If an overflow occurs, detect it and emit 300/// the specified diagnostic. 301void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 302 unsigned NewWidth, bool NewSign, 303 SourceLocation Loc, 304 unsigned DiagID) { 305 // Perform a conversion to the promoted condition type if needed. 306 if (NewWidth > Val.getBitWidth()) { 307 // If this is an extension, just do it. 308 Val = Val.extend(NewWidth); 309 Val.setIsSigned(NewSign); 310 311 // If the input was signed and negative and the output is 312 // unsigned, don't bother to warn: this is implementation-defined 313 // behavior. 314 // FIXME: Introduce a second, default-ignored warning for this case? 315 } else if (NewWidth < Val.getBitWidth()) { 316 // If this is a truncation, check for overflow. 317 llvm::APSInt ConvVal(Val); 318 ConvVal = ConvVal.trunc(NewWidth); 319 ConvVal.setIsSigned(NewSign); 320 ConvVal = ConvVal.extend(Val.getBitWidth()); 321 ConvVal.setIsSigned(Val.isSigned()); 322 if (ConvVal != Val) 323 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 324 325 // Regardless of whether a diagnostic was emitted, really do the 326 // truncation. 327 Val = Val.trunc(NewWidth); 328 Val.setIsSigned(NewSign); 329 } else if (NewSign != Val.isSigned()) { 330 // Convert the sign to match the sign of the condition. This can cause 331 // overflow as well: unsigned(INTMIN) 332 // We don't diagnose this overflow, because it is implementation-defined 333 // behavior. 334 // FIXME: Introduce a second, default-ignored warning for this case? 335 llvm::APSInt OldVal(Val); 336 Val.setIsSigned(NewSign); 337 } 338} 339 340namespace { 341 struct CaseCompareFunctor { 342 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 343 const llvm::APSInt &RHS) { 344 return LHS.first < RHS; 345 } 346 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 347 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 348 return LHS.first < RHS.first; 349 } 350 bool operator()(const llvm::APSInt &LHS, 351 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 352 return LHS < RHS.first; 353 } 354 }; 355} 356 357/// CmpCaseVals - Comparison predicate for sorting case values. 358/// 359static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 360 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 361 if (lhs.first < rhs.first) 362 return true; 363 364 if (lhs.first == rhs.first && 365 lhs.second->getCaseLoc().getRawEncoding() 366 < rhs.second->getCaseLoc().getRawEncoding()) 367 return true; 368 return false; 369} 370 371/// CmpEnumVals - Comparison predicate for sorting enumeration values. 372/// 373static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 374 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 375{ 376 return lhs.first < rhs.first; 377} 378 379/// EqEnumVals - Comparison preficate for uniqing enumeration values. 380/// 381static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 382 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 383{ 384 return lhs.first == rhs.first; 385} 386 387/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 388/// potentially integral-promoted expression @p expr. 389static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 390 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 391 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 392 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 393 if (TypeBeforePromotion->isIntegralOrEnumerationType()) { 394 return TypeBeforePromotion; 395 } 396 } 397 return expr->getType(); 398} 399 400StmtResult 401Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 402 Decl *CondVar) { 403 ExprResult CondResult; 404 405 VarDecl *ConditionVar = 0; 406 if (CondVar) { 407 ConditionVar = cast<VarDecl>(CondVar); 408 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 409 if (CondResult.isInvalid()) 410 return StmtError(); 411 412 Cond = CondResult.release(); 413 } 414 415 if (!Cond) 416 return StmtError(); 417 418 CondResult 419 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 420 PDiag(diag::err_typecheck_statement_requires_integer), 421 PDiag(diag::err_switch_incomplete_class_type) 422 << Cond->getSourceRange(), 423 PDiag(diag::err_switch_explicit_conversion), 424 PDiag(diag::note_switch_conversion), 425 PDiag(diag::err_switch_multiple_conversions), 426 PDiag(diag::note_switch_conversion), 427 PDiag(0)); 428 if (CondResult.isInvalid()) return StmtError(); 429 Cond = CondResult.take(); 430 431 if (!CondVar) { 432 CheckImplicitConversions(Cond, SwitchLoc); 433 CondResult = MaybeCreateExprWithCleanups(Cond); 434 if (CondResult.isInvalid()) 435 return StmtError(); 436 Cond = CondResult.take(); 437 } 438 439 getCurFunction()->setHasBranchIntoScope(); 440 441 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 442 getCurFunction()->SwitchStack.push_back(SS); 443 return Owned(SS); 444} 445 446static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 447 if (Val.getBitWidth() < BitWidth) 448 Val = Val.extend(BitWidth); 449 else if (Val.getBitWidth() > BitWidth) 450 Val = Val.trunc(BitWidth); 451 Val.setIsSigned(IsSigned); 452} 453 454StmtResult 455Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 456 Stmt *BodyStmt) { 457 SwitchStmt *SS = cast<SwitchStmt>(Switch); 458 assert(SS == getCurFunction()->SwitchStack.back() && 459 "switch stack missing push/pop!"); 460 461 SS->setBody(BodyStmt, SwitchLoc); 462 getCurFunction()->SwitchStack.pop_back(); 463 464 if (SS->getCond() == 0) 465 return StmtError(); 466 467 Expr *CondExpr = SS->getCond(); 468 Expr *CondExprBeforePromotion = CondExpr; 469 QualType CondTypeBeforePromotion = 470 GetTypeBeforeIntegralPromotion(CondExpr); 471 472 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 473 ExprResult CondResult = UsualUnaryConversions(CondExpr); 474 if (CondResult.isInvalid()) 475 return StmtError(); 476 CondExpr = CondResult.take(); 477 QualType CondType = CondExpr->getType(); 478 SS->setCond(CondExpr); 479 480 // C++ 6.4.2.p2: 481 // Integral promotions are performed (on the switch condition). 482 // 483 // A case value unrepresentable by the original switch condition 484 // type (before the promotion) doesn't make sense, even when it can 485 // be represented by the promoted type. Therefore we need to find 486 // the pre-promotion type of the switch condition. 487 if (!CondExpr->isTypeDependent()) { 488 // We have already converted the expression to an integral or enumeration 489 // type, when we started the switch statement. If we don't have an 490 // appropriate type now, just return an error. 491 if (!CondType->isIntegralOrEnumerationType()) 492 return StmtError(); 493 494 if (CondExpr->isKnownToHaveBooleanValue()) { 495 // switch(bool_expr) {...} is often a programmer error, e.g. 496 // switch(n && mask) { ... } // Doh - should be "n & mask". 497 // One can always use an if statement instead of switch(bool_expr). 498 Diag(SwitchLoc, diag::warn_bool_switch_condition) 499 << CondExpr->getSourceRange(); 500 } 501 } 502 503 // Get the bitwidth of the switched-on value before promotions. We must 504 // convert the integer case values to this width before comparison. 505 bool HasDependentValue 506 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 507 unsigned CondWidth 508 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 509 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 510 511 // Accumulate all of the case values in a vector so that we can sort them 512 // and detect duplicates. This vector contains the APInt for the case after 513 // it has been converted to the condition type. 514 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 515 CaseValsTy CaseVals; 516 517 // Keep track of any GNU case ranges we see. The APSInt is the low value. 518 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 519 CaseRangesTy CaseRanges; 520 521 DefaultStmt *TheDefaultStmt = 0; 522 523 bool CaseListIsErroneous = false; 524 525 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 526 SC = SC->getNextSwitchCase()) { 527 528 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 529 if (TheDefaultStmt) { 530 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 531 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 532 533 // FIXME: Remove the default statement from the switch block so that 534 // we'll return a valid AST. This requires recursing down the AST and 535 // finding it, not something we are set up to do right now. For now, 536 // just lop the entire switch stmt out of the AST. 537 CaseListIsErroneous = true; 538 } 539 TheDefaultStmt = DS; 540 541 } else { 542 CaseStmt *CS = cast<CaseStmt>(SC); 543 544 // We already verified that the expression has a i-c-e value (C99 545 // 6.8.4.2p3) - get that value now. 546 Expr *Lo = CS->getLHS(); 547 548 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 549 HasDependentValue = true; 550 break; 551 } 552 553 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 554 555 // Convert the value to the same width/sign as the condition. 556 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 557 Lo->getLocStart(), 558 diag::warn_case_value_overflow); 559 560 // If the LHS is not the same type as the condition, insert an implicit 561 // cast. 562 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 563 CS->setLHS(Lo); 564 565 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 566 if (CS->getRHS()) { 567 if (CS->getRHS()->isTypeDependent() || 568 CS->getRHS()->isValueDependent()) { 569 HasDependentValue = true; 570 break; 571 } 572 CaseRanges.push_back(std::make_pair(LoVal, CS)); 573 } else 574 CaseVals.push_back(std::make_pair(LoVal, CS)); 575 } 576 } 577 578 if (!HasDependentValue) { 579 // If we don't have a default statement, check whether the 580 // condition is constant. 581 llvm::APSInt ConstantCondValue; 582 bool HasConstantCond = false; 583 bool ShouldCheckConstantCond = false; 584 if (!HasDependentValue && !TheDefaultStmt) { 585 Expr::EvalResult Result; 586 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 587 if (HasConstantCond) { 588 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 589 ConstantCondValue = Result.Val.getInt(); 590 ShouldCheckConstantCond = true; 591 592 assert(ConstantCondValue.getBitWidth() == CondWidth && 593 ConstantCondValue.isSigned() == CondIsSigned); 594 } 595 } 596 597 // Sort all the scalar case values so we can easily detect duplicates. 598 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 599 600 if (!CaseVals.empty()) { 601 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 602 if (ShouldCheckConstantCond && 603 CaseVals[i].first == ConstantCondValue) 604 ShouldCheckConstantCond = false; 605 606 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 607 // If we have a duplicate, report it. 608 Diag(CaseVals[i].second->getLHS()->getLocStart(), 609 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 610 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 611 diag::note_duplicate_case_prev); 612 // FIXME: We really want to remove the bogus case stmt from the 613 // substmt, but we have no way to do this right now. 614 CaseListIsErroneous = true; 615 } 616 } 617 } 618 619 // Detect duplicate case ranges, which usually don't exist at all in 620 // the first place. 621 if (!CaseRanges.empty()) { 622 // Sort all the case ranges by their low value so we can easily detect 623 // overlaps between ranges. 624 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 625 626 // Scan the ranges, computing the high values and removing empty ranges. 627 std::vector<llvm::APSInt> HiVals; 628 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 629 llvm::APSInt &LoVal = CaseRanges[i].first; 630 CaseStmt *CR = CaseRanges[i].second; 631 Expr *Hi = CR->getRHS(); 632 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 633 634 // Convert the value to the same width/sign as the condition. 635 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 636 Hi->getLocStart(), 637 diag::warn_case_value_overflow); 638 639 // If the LHS is not the same type as the condition, insert an implicit 640 // cast. 641 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 642 CR->setRHS(Hi); 643 644 // If the low value is bigger than the high value, the case is empty. 645 if (LoVal > HiVal) { 646 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 647 << SourceRange(CR->getLHS()->getLocStart(), 648 Hi->getLocEnd()); 649 CaseRanges.erase(CaseRanges.begin()+i); 650 --i, --e; 651 continue; 652 } 653 654 if (ShouldCheckConstantCond && 655 LoVal <= ConstantCondValue && 656 ConstantCondValue <= HiVal) 657 ShouldCheckConstantCond = false; 658 659 HiVals.push_back(HiVal); 660 } 661 662 // Rescan the ranges, looking for overlap with singleton values and other 663 // ranges. Since the range list is sorted, we only need to compare case 664 // ranges with their neighbors. 665 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 666 llvm::APSInt &CRLo = CaseRanges[i].first; 667 llvm::APSInt &CRHi = HiVals[i]; 668 CaseStmt *CR = CaseRanges[i].second; 669 670 // Check to see whether the case range overlaps with any 671 // singleton cases. 672 CaseStmt *OverlapStmt = 0; 673 llvm::APSInt OverlapVal(32); 674 675 // Find the smallest value >= the lower bound. If I is in the 676 // case range, then we have overlap. 677 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 678 CaseVals.end(), CRLo, 679 CaseCompareFunctor()); 680 if (I != CaseVals.end() && I->first < CRHi) { 681 OverlapVal = I->first; // Found overlap with scalar. 682 OverlapStmt = I->second; 683 } 684 685 // Find the smallest value bigger than the upper bound. 686 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 687 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 688 OverlapVal = (I-1)->first; // Found overlap with scalar. 689 OverlapStmt = (I-1)->second; 690 } 691 692 // Check to see if this case stmt overlaps with the subsequent 693 // case range. 694 if (i && CRLo <= HiVals[i-1]) { 695 OverlapVal = HiVals[i-1]; // Found overlap with range. 696 OverlapStmt = CaseRanges[i-1].second; 697 } 698 699 if (OverlapStmt) { 700 // If we have a duplicate, report it. 701 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 702 << OverlapVal.toString(10); 703 Diag(OverlapStmt->getLHS()->getLocStart(), 704 diag::note_duplicate_case_prev); 705 // FIXME: We really want to remove the bogus case stmt from the 706 // substmt, but we have no way to do this right now. 707 CaseListIsErroneous = true; 708 } 709 } 710 } 711 712 // Complain if we have a constant condition and we didn't find a match. 713 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 714 // TODO: it would be nice if we printed enums as enums, chars as 715 // chars, etc. 716 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 717 << ConstantCondValue.toString(10) 718 << CondExpr->getSourceRange(); 719 } 720 721 // Check to see if switch is over an Enum and handles all of its 722 // values. We only issue a warning if there is not 'default:', but 723 // we still do the analysis to preserve this information in the AST 724 // (which can be used by flow-based analyes). 725 // 726 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 727 728 // If switch has default case, then ignore it. 729 if (!CaseListIsErroneous && !HasConstantCond && ET) { 730 const EnumDecl *ED = ET->getDecl(); 731 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 732 EnumValsTy EnumVals; 733 734 // Gather all enum values, set their type and sort them, 735 // allowing easier comparison with CaseVals. 736 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 737 EDI != ED->enumerator_end(); ++EDI) { 738 llvm::APSInt Val = EDI->getInitVal(); 739 AdjustAPSInt(Val, CondWidth, CondIsSigned); 740 EnumVals.push_back(std::make_pair(Val, *EDI)); 741 } 742 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 743 EnumValsTy::iterator EIend = 744 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 745 746 // See which case values aren't in enum. 747 // TODO: we might want to check whether case values are out of the 748 // enum even if we don't want to check whether all cases are handled. 749 if (!TheDefaultStmt) { 750 EnumValsTy::const_iterator EI = EnumVals.begin(); 751 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 752 CI != CaseVals.end(); CI++) { 753 while (EI != EIend && EI->first < CI->first) 754 EI++; 755 if (EI == EIend || EI->first > CI->first) 756 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 757 << ED->getDeclName(); 758 } 759 // See which of case ranges aren't in enum 760 EI = EnumVals.begin(); 761 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 762 RI != CaseRanges.end() && EI != EIend; RI++) { 763 while (EI != EIend && EI->first < RI->first) 764 EI++; 765 766 if (EI == EIend || EI->first != RI->first) { 767 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 768 << ED->getDeclName(); 769 } 770 771 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 772 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 773 while (EI != EIend && EI->first < Hi) 774 EI++; 775 if (EI == EIend || EI->first != Hi) 776 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 777 << ED->getDeclName(); 778 } 779 } 780 781 // Check which enum vals aren't in switch 782 CaseValsTy::const_iterator CI = CaseVals.begin(); 783 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 784 bool hasCasesNotInSwitch = false; 785 786 llvm::SmallVector<DeclarationName,8> UnhandledNames; 787 788 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 789 // Drop unneeded case values 790 llvm::APSInt CIVal; 791 while (CI != CaseVals.end() && CI->first < EI->first) 792 CI++; 793 794 if (CI != CaseVals.end() && CI->first == EI->first) 795 continue; 796 797 // Drop unneeded case ranges 798 for (; RI != CaseRanges.end(); RI++) { 799 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 800 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 801 if (EI->first <= Hi) 802 break; 803 } 804 805 if (RI == CaseRanges.end() || EI->first < RI->first) { 806 hasCasesNotInSwitch = true; 807 if (!TheDefaultStmt) 808 UnhandledNames.push_back(EI->second->getDeclName()); 809 } 810 } 811 812 // Produce a nice diagnostic if multiple values aren't handled. 813 switch (UnhandledNames.size()) { 814 case 0: break; 815 case 1: 816 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 817 << UnhandledNames[0]; 818 break; 819 case 2: 820 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 821 << UnhandledNames[0] << UnhandledNames[1]; 822 break; 823 case 3: 824 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 825 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 826 break; 827 default: 828 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 829 << (unsigned)UnhandledNames.size() 830 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 831 break; 832 } 833 834 if (!hasCasesNotInSwitch) 835 SS->setAllEnumCasesCovered(); 836 } 837 } 838 839 // FIXME: If the case list was broken is some way, we don't have a good system 840 // to patch it up. Instead, just return the whole substmt as broken. 841 if (CaseListIsErroneous) 842 return StmtError(); 843 844 return Owned(SS); 845} 846 847StmtResult 848Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 849 Decl *CondVar, Stmt *Body) { 850 ExprResult CondResult(Cond.release()); 851 852 VarDecl *ConditionVar = 0; 853 if (CondVar) { 854 ConditionVar = cast<VarDecl>(CondVar); 855 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 856 if (CondResult.isInvalid()) 857 return StmtError(); 858 } 859 Expr *ConditionExpr = CondResult.take(); 860 if (!ConditionExpr) 861 return StmtError(); 862 863 DiagnoseUnusedExprResult(Body); 864 865 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 866 Body, WhileLoc)); 867} 868 869StmtResult 870Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 871 SourceLocation WhileLoc, SourceLocation CondLParen, 872 Expr *Cond, SourceLocation CondRParen) { 873 assert(Cond && "ActOnDoStmt(): missing expression"); 874 875 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 876 if (CondResult.isInvalid() || CondResult.isInvalid()) 877 return StmtError(); 878 Cond = CondResult.take(); 879 880 CheckImplicitConversions(Cond, DoLoc); 881 CondResult = MaybeCreateExprWithCleanups(Cond); 882 if (CondResult.isInvalid()) 883 return StmtError(); 884 Cond = CondResult.take(); 885 886 DiagnoseUnusedExprResult(Body); 887 888 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 889} 890 891StmtResult 892Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 893 Stmt *First, FullExprArg second, Decl *secondVar, 894 FullExprArg third, 895 SourceLocation RParenLoc, Stmt *Body) { 896 if (!getLangOptions().CPlusPlus) { 897 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 898 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 899 // declare identifiers for objects having storage class 'auto' or 900 // 'register'. 901 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 902 DI!=DE; ++DI) { 903 VarDecl *VD = dyn_cast<VarDecl>(*DI); 904 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 905 VD = 0; 906 if (VD == 0) 907 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 908 // FIXME: mark decl erroneous! 909 } 910 } 911 } 912 913 ExprResult SecondResult(second.release()); 914 VarDecl *ConditionVar = 0; 915 if (secondVar) { 916 ConditionVar = cast<VarDecl>(secondVar); 917 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 918 if (SecondResult.isInvalid()) 919 return StmtError(); 920 } 921 922 Expr *Third = third.release().takeAs<Expr>(); 923 924 DiagnoseUnusedExprResult(First); 925 DiagnoseUnusedExprResult(Third); 926 DiagnoseUnusedExprResult(Body); 927 928 return Owned(new (Context) ForStmt(Context, First, 929 SecondResult.take(), ConditionVar, 930 Third, Body, ForLoc, LParenLoc, 931 RParenLoc)); 932} 933 934/// In an Objective C collection iteration statement: 935/// for (x in y) 936/// x can be an arbitrary l-value expression. Bind it up as a 937/// full-expression. 938StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 939 CheckImplicitConversions(E); 940 ExprResult Result = MaybeCreateExprWithCleanups(E); 941 if (Result.isInvalid()) return StmtError(); 942 return Owned(static_cast<Stmt*>(Result.get())); 943} 944 945StmtResult 946Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 947 SourceLocation LParenLoc, 948 Stmt *First, Expr *Second, 949 SourceLocation RParenLoc, Stmt *Body) { 950 if (First) { 951 QualType FirstType; 952 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 953 if (!DS->isSingleDecl()) 954 return StmtError(Diag((*DS->decl_begin())->getLocation(), 955 diag::err_toomany_element_decls)); 956 957 Decl *D = DS->getSingleDecl(); 958 FirstType = cast<ValueDecl>(D)->getType(); 959 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 960 // declare identifiers for objects having storage class 'auto' or 961 // 'register'. 962 VarDecl *VD = cast<VarDecl>(D); 963 if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) 964 return StmtError(Diag(VD->getLocation(), 965 diag::err_non_variable_decl_in_for)); 966 } else { 967 Expr *FirstE = cast<Expr>(First); 968 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 969 return StmtError(Diag(First->getLocStart(), 970 diag::err_selector_element_not_lvalue) 971 << First->getSourceRange()); 972 973 FirstType = static_cast<Expr*>(First)->getType(); 974 } 975 if (!FirstType->isDependentType() && 976 !FirstType->isObjCObjectPointerType() && 977 !FirstType->isBlockPointerType()) 978 Diag(ForLoc, diag::err_selector_element_type) 979 << FirstType << First->getSourceRange(); 980 } 981 if (Second && !Second->isTypeDependent()) { 982 ExprResult Result = DefaultFunctionArrayLvalueConversion(Second); 983 if (Result.isInvalid()) 984 return StmtError(); 985 Second = Result.take(); 986 QualType SecondType = Second->getType(); 987 if (!SecondType->isObjCObjectPointerType()) 988 Diag(ForLoc, diag::err_collection_expr_type) 989 << SecondType << Second->getSourceRange(); 990 else if (const ObjCObjectPointerType *OPT = 991 SecondType->getAsObjCInterfacePointerType()) { 992 llvm::SmallVector<IdentifierInfo *, 4> KeyIdents; 993 IdentifierInfo* selIdent = 994 &Context.Idents.get("countByEnumeratingWithState"); 995 KeyIdents.push_back(selIdent); 996 selIdent = &Context.Idents.get("objects"); 997 KeyIdents.push_back(selIdent); 998 selIdent = &Context.Idents.get("count"); 999 KeyIdents.push_back(selIdent); 1000 Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]); 1001 if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) { 1002 if (!IDecl->isForwardDecl() && 1003 !IDecl->lookupInstanceMethod(CSelector) && 1004 !LookupMethodInQualifiedType(CSelector, OPT, true)) { 1005 // Must further look into private implementation methods. 1006 if (!LookupPrivateInstanceMethod(CSelector, IDecl)) 1007 Diag(ForLoc, diag::warn_collection_expr_type) 1008 << SecondType << CSelector << Second->getSourceRange(); 1009 } 1010 } 1011 } 1012 } 1013 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1014 ForLoc, RParenLoc)); 1015} 1016 1017namespace { 1018 1019enum BeginEndFunction { 1020 BEF_begin, 1021 BEF_end 1022}; 1023 1024/// Build a variable declaration for a for-range statement. 1025static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1026 QualType Type, const char *Name) { 1027 DeclContext *DC = SemaRef.CurContext; 1028 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1029 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1030 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1031 TInfo, SC_Auto, SC_None); 1032 Decl->setImplicit(); 1033 return Decl; 1034} 1035 1036/// Finish building a variable declaration for a for-range statement. 1037/// \return true if an error occurs. 1038static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1039 SourceLocation Loc, int diag) { 1040 // Deduce the type for the iterator variable now rather than leaving it to 1041 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1042 TypeSourceInfo *InitTSI = 0; 1043 if (Init->getType()->isVoidType() || 1044 !SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI)) 1045 SemaRef.Diag(Loc, diag) << Init->getType(); 1046 if (!InitTSI) { 1047 Decl->setInvalidDecl(); 1048 return true; 1049 } 1050 Decl->setTypeSourceInfo(InitTSI); 1051 Decl->setType(InitTSI->getType()); 1052 1053 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1054 /*TypeMayContainAuto=*/false); 1055 SemaRef.FinalizeDeclaration(Decl); 1056 SemaRef.CurContext->addHiddenDecl(Decl); 1057 return false; 1058} 1059 1060/// Produce a note indicating which begin/end function was implicitly called 1061/// by a C++0x for-range statement. This is often not obvious from the code, 1062/// nor from the diagnostics produced when analysing the implicit expressions 1063/// required in a for-range statement. 1064void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1065 BeginEndFunction BEF) { 1066 CallExpr *CE = dyn_cast<CallExpr>(E); 1067 if (!CE) 1068 return; 1069 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1070 if (!D) 1071 return; 1072 SourceLocation Loc = D->getLocation(); 1073 1074 std::string Description; 1075 bool IsTemplate = false; 1076 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1077 Description = SemaRef.getTemplateArgumentBindingsText( 1078 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1079 IsTemplate = true; 1080 } 1081 1082 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1083 << BEF << IsTemplate << Description << E->getType(); 1084} 1085 1086/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1087/// given LookupResult is non-empty, it is assumed to describe a member which 1088/// will be invoked. Otherwise, the function will be found via argument 1089/// dependent lookup. 1090static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1091 SourceLocation Loc, 1092 VarDecl *Decl, 1093 BeginEndFunction BEF, 1094 const DeclarationNameInfo &NameInfo, 1095 LookupResult &MemberLookup, 1096 Expr *Range) { 1097 ExprResult CallExpr; 1098 if (!MemberLookup.empty()) { 1099 ExprResult MemberRef = 1100 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1101 /*IsPtr=*/false, CXXScopeSpec(), 1102 /*Qualifier=*/0, MemberLookup, 1103 /*TemplateArgs=*/0); 1104 if (MemberRef.isInvalid()) 1105 return ExprError(); 1106 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1107 Loc, 0); 1108 if (CallExpr.isInvalid()) 1109 return ExprError(); 1110 } else { 1111 UnresolvedSet<0> FoundNames; 1112 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1113 // std is an associated namespace. 1114 UnresolvedLookupExpr *Fn = 1115 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1116 NestedNameSpecifierLoc(), NameInfo, 1117 /*NeedsADL=*/true, /*Overloaded=*/false, 1118 FoundNames.begin(), FoundNames.end(), 1119 /*LookInStdNamespace=*/true); 1120 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1121 0); 1122 if (CallExpr.isInvalid()) { 1123 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1124 << Range->getType(); 1125 return ExprError(); 1126 } 1127 } 1128 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1129 diag::err_for_range_iter_deduction_failure)) { 1130 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1131 return ExprError(); 1132 } 1133 return CallExpr; 1134} 1135 1136} 1137 1138/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1139/// 1140/// C++0x [stmt.ranged]: 1141/// A range-based for statement is equivalent to 1142/// 1143/// { 1144/// auto && __range = range-init; 1145/// for ( auto __begin = begin-expr, 1146/// __end = end-expr; 1147/// __begin != __end; 1148/// ++__begin ) { 1149/// for-range-declaration = *__begin; 1150/// statement 1151/// } 1152/// } 1153/// 1154/// The body of the loop is not available yet, since it cannot be analysed until 1155/// we have determined the type of the for-range-declaration. 1156StmtResult 1157Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1158 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1159 SourceLocation RParenLoc) { 1160 if (!First || !Range) 1161 return StmtError(); 1162 1163 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1164 assert(DS && "first part of for range not a decl stmt"); 1165 1166 if (!DS->isSingleDecl()) { 1167 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1168 return StmtError(); 1169 } 1170 if (DS->getSingleDecl()->isInvalidDecl()) 1171 return StmtError(); 1172 1173 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1174 return StmtError(); 1175 1176 // Build auto && __range = range-init 1177 SourceLocation RangeLoc = Range->getLocStart(); 1178 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1179 Context.getAutoRRefDeductType(), 1180 "__range"); 1181 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1182 diag::err_for_range_deduction_failure)) 1183 return StmtError(); 1184 1185 // Claim the type doesn't contain auto: we've already done the checking. 1186 DeclGroupPtrTy RangeGroup = 1187 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1188 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1189 if (RangeDecl.isInvalid()) 1190 return StmtError(); 1191 1192 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1193 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1194 RParenLoc); 1195} 1196 1197/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1198StmtResult 1199Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1200 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1201 Expr *Inc, Stmt *LoopVarDecl, 1202 SourceLocation RParenLoc) { 1203 Scope *S = getCurScope(); 1204 1205 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1206 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1207 QualType RangeVarType = RangeVar->getType(); 1208 1209 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1210 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1211 1212 StmtResult BeginEndDecl = BeginEnd; 1213 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1214 1215 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1216 SourceLocation RangeLoc = RangeVar->getLocation(); 1217 1218 ExprResult RangeRef = BuildDeclRefExpr(RangeVar, 1219 RangeVarType.getNonReferenceType(), 1220 VK_LValue, ColonLoc); 1221 if (RangeRef.isInvalid()) 1222 return StmtError(); 1223 1224 QualType AutoType = Context.getAutoDeductType(); 1225 Expr *Range = RangeVar->getInit(); 1226 if (!Range) 1227 return StmtError(); 1228 QualType RangeType = Range->getType(); 1229 1230 if (RequireCompleteType(RangeLoc, RangeType, 1231 PDiag(diag::err_for_range_incomplete_type))) 1232 return StmtError(); 1233 1234 // Build auto __begin = begin-expr, __end = end-expr. 1235 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1236 "__begin"); 1237 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1238 "__end"); 1239 1240 // Build begin-expr and end-expr and attach to __begin and __end variables. 1241 ExprResult BeginExpr, EndExpr; 1242 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1243 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1244 // __range + __bound, respectively, where __bound is the array bound. If 1245 // _RangeT is an array of unknown size or an array of incomplete type, 1246 // the program is ill-formed; 1247 1248 // begin-expr is __range. 1249 BeginExpr = RangeRef; 1250 if (FinishForRangeVarDecl(*this, BeginVar, RangeRef.get(), ColonLoc, 1251 diag::err_for_range_iter_deduction_failure)) { 1252 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1253 return StmtError(); 1254 } 1255 1256 // Find the array bound. 1257 ExprResult BoundExpr; 1258 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1259 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1260 Context.IntTy, RangeLoc)); 1261 else if (const VariableArrayType *VAT = 1262 dyn_cast<VariableArrayType>(UnqAT)) 1263 BoundExpr = VAT->getSizeExpr(); 1264 else { 1265 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1266 // UnqAT is not incomplete and Range is not type-dependent. 1267 assert(0 && "Unexpected array type in for-range"); 1268 return StmtError(); 1269 } 1270 1271 // end-expr is __range + __bound. 1272 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, RangeRef.get(), 1273 BoundExpr.get()); 1274 if (EndExpr.isInvalid()) 1275 return StmtError(); 1276 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1277 diag::err_for_range_iter_deduction_failure)) { 1278 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1279 return StmtError(); 1280 } 1281 } else { 1282 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1283 ColonLoc); 1284 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1285 ColonLoc); 1286 1287 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1288 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1289 1290 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1291 // - if _RangeT is a class type, the unqualified-ids begin and end are 1292 // looked up in the scope of class _RangeT as if by class member access 1293 // lookup (3.4.5), and if either (or both) finds at least one 1294 // declaration, begin-expr and end-expr are __range.begin() and 1295 // __range.end(), respectively; 1296 LookupQualifiedName(BeginMemberLookup, D); 1297 LookupQualifiedName(EndMemberLookup, D); 1298 1299 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1300 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1301 << RangeType << BeginMemberLookup.empty(); 1302 return StmtError(); 1303 } 1304 } else { 1305 // - otherwise, begin-expr and end-expr are begin(__range) and 1306 // end(__range), respectively, where begin and end are looked up with 1307 // argument-dependent lookup (3.4.2). For the purposes of this name 1308 // lookup, namespace std is an associated namespace. 1309 } 1310 1311 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1312 BEF_begin, BeginNameInfo, 1313 BeginMemberLookup, RangeRef.get()); 1314 if (BeginExpr.isInvalid()) 1315 return StmtError(); 1316 1317 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1318 BEF_end, EndNameInfo, 1319 EndMemberLookup, RangeRef.get()); 1320 if (EndExpr.isInvalid()) 1321 return StmtError(); 1322 } 1323 1324 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1325 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1326 if (!Context.hasSameType(BeginType, EndType)) { 1327 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1328 << BeginType << EndType; 1329 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1330 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1331 } 1332 1333 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1334 // Claim the type doesn't contain auto: we've already done the checking. 1335 DeclGroupPtrTy BeginEndGroup = 1336 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1337 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1338 1339 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, 1340 BeginType.getNonReferenceType(), 1341 VK_LValue, ColonLoc); 1342 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1343 VK_LValue, ColonLoc); 1344 1345 // Build and check __begin != __end expression. 1346 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1347 BeginRef.get(), EndRef.get()); 1348 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1349 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1350 if (NotEqExpr.isInvalid()) { 1351 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1352 if (!Context.hasSameType(BeginType, EndType)) 1353 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1354 return StmtError(); 1355 } 1356 1357 // Build and check ++__begin expression. 1358 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1359 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1360 if (IncrExpr.isInvalid()) { 1361 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1362 return StmtError(); 1363 } 1364 1365 // Build and check *__begin expression. 1366 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1367 if (DerefExpr.isInvalid()) { 1368 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1369 return StmtError(); 1370 } 1371 1372 // Attach *__begin as initializer for VD. 1373 if (!LoopVar->isInvalidDecl()) { 1374 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1375 /*TypeMayContainAuto=*/true); 1376 if (LoopVar->isInvalidDecl()) 1377 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1378 } 1379 } 1380 1381 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1382 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1383 NotEqExpr.take(), IncrExpr.take(), 1384 LoopVarDS, /*Body=*/0, ForLoc, 1385 ColonLoc, RParenLoc)); 1386} 1387 1388/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1389/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1390/// body cannot be performed until after the type of the range variable is 1391/// determined. 1392StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1393 if (!S || !B) 1394 return StmtError(); 1395 1396 cast<CXXForRangeStmt>(S)->setBody(B); 1397 return S; 1398} 1399 1400StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1401 SourceLocation LabelLoc, 1402 LabelDecl *TheDecl) { 1403 getCurFunction()->setHasBranchIntoScope(); 1404 TheDecl->setUsed(); 1405 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1406} 1407 1408StmtResult 1409Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1410 Expr *E) { 1411 // Convert operand to void* 1412 if (!E->isTypeDependent()) { 1413 QualType ETy = E->getType(); 1414 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1415 ExprResult ExprRes = Owned(E); 1416 AssignConvertType ConvTy = 1417 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1418 if (ExprRes.isInvalid()) 1419 return StmtError(); 1420 E = ExprRes.take(); 1421 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1422 return StmtError(); 1423 } 1424 1425 getCurFunction()->setHasIndirectGoto(); 1426 1427 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1428} 1429 1430StmtResult 1431Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1432 Scope *S = CurScope->getContinueParent(); 1433 if (!S) { 1434 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1435 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1436 } 1437 1438 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1439} 1440 1441StmtResult 1442Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1443 Scope *S = CurScope->getBreakParent(); 1444 if (!S) { 1445 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1446 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1447 } 1448 1449 return Owned(new (Context) BreakStmt(BreakLoc)); 1450} 1451 1452/// \brief Determine whether the given expression is a candidate for 1453/// copy elision in either a return statement or a throw expression. 1454/// 1455/// \param ReturnType If we're determining the copy elision candidate for 1456/// a return statement, this is the return type of the function. If we're 1457/// determining the copy elision candidate for a throw expression, this will 1458/// be a NULL type. 1459/// 1460/// \param E The expression being returned from the function or block, or 1461/// being thrown. 1462/// 1463/// \param AllowFunctionParameter 1464/// 1465/// \returns The NRVO candidate variable, if the return statement may use the 1466/// NRVO, or NULL if there is no such candidate. 1467const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1468 Expr *E, 1469 bool AllowFunctionParameter) { 1470 QualType ExprType = E->getType(); 1471 // - in a return statement in a function with ... 1472 // ... a class return type ... 1473 if (!ReturnType.isNull()) { 1474 if (!ReturnType->isRecordType()) 1475 return 0; 1476 // ... the same cv-unqualified type as the function return type ... 1477 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1478 return 0; 1479 } 1480 1481 // ... the expression is the name of a non-volatile automatic object 1482 // (other than a function or catch-clause parameter)) ... 1483 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1484 if (!DR) 1485 return 0; 1486 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1487 if (!VD) 1488 return 0; 1489 1490 if (VD->hasLocalStorage() && !VD->isExceptionVariable() && 1491 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1492 !VD->getType().isVolatileQualified() && 1493 ((VD->getKind() == Decl::Var) || 1494 (AllowFunctionParameter && VD->getKind() == Decl::ParmVar))) 1495 return VD; 1496 1497 return 0; 1498} 1499 1500/// \brief Perform the initialization of a potentially-movable value, which 1501/// is the result of return value. 1502/// 1503/// This routine implements C++0x [class.copy]p33, which attempts to treat 1504/// returned lvalues as rvalues in certain cases (to prefer move construction), 1505/// then falls back to treating them as lvalues if that failed. 1506ExprResult 1507Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1508 const VarDecl *NRVOCandidate, 1509 QualType ResultType, 1510 Expr *Value) { 1511 // C++0x [class.copy]p33: 1512 // When the criteria for elision of a copy operation are met or would 1513 // be met save for the fact that the source object is a function 1514 // parameter, and the object to be copied is designated by an lvalue, 1515 // overload resolution to select the constructor for the copy is first 1516 // performed as if the object were designated by an rvalue. 1517 ExprResult Res = ExprError(); 1518 if (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true)) { 1519 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1520 Value->getType(), CK_LValueToRValue, 1521 Value, VK_XValue); 1522 1523 Expr *InitExpr = &AsRvalue; 1524 InitializationKind Kind 1525 = InitializationKind::CreateCopy(Value->getLocStart(), 1526 Value->getLocStart()); 1527 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1528 1529 // [...] If overload resolution fails, or if the type of the first 1530 // parameter of the selected constructor is not an rvalue reference 1531 // to the object's type (possibly cv-qualified), overload resolution 1532 // is performed again, considering the object as an lvalue. 1533 if (Seq.getKind() != InitializationSequence::FailedSequence) { 1534 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1535 StepEnd = Seq.step_end(); 1536 Step != StepEnd; ++Step) { 1537 if (Step->Kind 1538 != InitializationSequence::SK_ConstructorInitialization) 1539 continue; 1540 1541 CXXConstructorDecl *Constructor 1542 = cast<CXXConstructorDecl>(Step->Function.Function); 1543 1544 const RValueReferenceType *RRefType 1545 = Constructor->getParamDecl(0)->getType() 1546 ->getAs<RValueReferenceType>(); 1547 1548 // If we don't meet the criteria, break out now. 1549 if (!RRefType || 1550 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1551 Context.getTypeDeclType(Constructor->getParent()))) 1552 break; 1553 1554 // Promote "AsRvalue" to the heap, since we now need this 1555 // expression node to persist. 1556 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1557 CK_LValueToRValue, Value, 0, 1558 VK_XValue); 1559 1560 // Complete type-checking the initialization of the return type 1561 // using the constructor we found. 1562 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1563 } 1564 } 1565 } 1566 1567 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1568 // above, or overload resolution failed. Either way, we need to try 1569 // (again) now with the return value expression as written. 1570 if (Res.isInvalid()) 1571 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1572 1573 return Res; 1574} 1575 1576/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1577/// 1578StmtResult 1579Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1580 // If this is the first return we've seen in the block, infer the type of 1581 // the block from it. 1582 BlockScopeInfo *CurBlock = getCurBlock(); 1583 if (CurBlock->ReturnType.isNull()) { 1584 if (RetValExp) { 1585 // Don't call UsualUnaryConversions(), since we don't want to do 1586 // integer promotions here. 1587 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 1588 if (Result.isInvalid()) 1589 return StmtError(); 1590 RetValExp = Result.take(); 1591 CurBlock->ReturnType = RetValExp->getType(); 1592 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1593 // We have to remove a 'const' added to copied-in variable which was 1594 // part of the implementation spec. and not the actual qualifier for 1595 // the variable. 1596 if (CDRE->isConstQualAdded()) 1597 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1598 } 1599 } else 1600 CurBlock->ReturnType = Context.VoidTy; 1601 } 1602 QualType FnRetType = CurBlock->ReturnType; 1603 1604 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1605 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1606 << getCurFunctionOrMethodDecl()->getDeclName(); 1607 return StmtError(); 1608 } 1609 1610 // Otherwise, verify that this result type matches the previous one. We are 1611 // pickier with blocks than for normal functions because we don't have GCC 1612 // compatibility to worry about here. 1613 ReturnStmt *Result = 0; 1614 if (CurBlock->ReturnType->isVoidType()) { 1615 if (RetValExp) { 1616 Diag(ReturnLoc, diag::err_return_block_has_expr); 1617 RetValExp = 0; 1618 } 1619 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1620 } else if (!RetValExp) { 1621 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1622 } else { 1623 const VarDecl *NRVOCandidate = 0; 1624 1625 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1626 // we have a non-void block with an expression, continue checking 1627 1628 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1629 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1630 // function return. 1631 1632 // In C++ the return statement is handled via a copy initialization. 1633 // the C version of which boils down to CheckSingleAssignmentConstraints. 1634 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1635 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1636 FnRetType, 1637 NRVOCandidate != 0); 1638 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1639 FnRetType, RetValExp); 1640 if (Res.isInvalid()) { 1641 // FIXME: Cleanup temporaries here, anyway? 1642 return StmtError(); 1643 } 1644 1645 if (RetValExp) { 1646 CheckImplicitConversions(RetValExp, ReturnLoc); 1647 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1648 } 1649 1650 RetValExp = Res.takeAs<Expr>(); 1651 if (RetValExp) 1652 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1653 } 1654 1655 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1656 } 1657 1658 // If we need to check for the named return value optimization, save the 1659 // return statement in our scope for later processing. 1660 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1661 !CurContext->isDependentContext()) 1662 FunctionScopes.back()->Returns.push_back(Result); 1663 1664 return Owned(Result); 1665} 1666 1667StmtResult 1668Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1669 if (getCurBlock()) 1670 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1671 1672 QualType FnRetType; 1673 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1674 FnRetType = FD->getResultType(); 1675 if (FD->hasAttr<NoReturnAttr>() || 1676 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1677 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1678 << getCurFunctionOrMethodDecl()->getDeclName(); 1679 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1680 FnRetType = MD->getResultType(); 1681 else // If we don't have a function/method context, bail. 1682 return StmtError(); 1683 1684 ReturnStmt *Result = 0; 1685 if (FnRetType->isVoidType()) { 1686 if (RetValExp && !RetValExp->isTypeDependent()) { 1687 // C99 6.8.6.4p1 (ext_ since GCC warns) 1688 unsigned D = diag::ext_return_has_expr; 1689 if (RetValExp->getType()->isVoidType()) 1690 D = diag::ext_return_has_void_expr; 1691 else { 1692 ExprResult Result = Owned(RetValExp); 1693 Result = IgnoredValueConversions(Result.take()); 1694 if (Result.isInvalid()) 1695 return StmtError(); 1696 RetValExp = Result.take(); 1697 RetValExp = ImpCastExprToType(RetValExp, Context.VoidTy, CK_ToVoid).take(); 1698 } 1699 1700 // return (some void expression); is legal in C++. 1701 if (D != diag::ext_return_has_void_expr || 1702 !getLangOptions().CPlusPlus) { 1703 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1704 Diag(ReturnLoc, D) 1705 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1706 << RetValExp->getSourceRange(); 1707 } 1708 1709 CheckImplicitConversions(RetValExp, ReturnLoc); 1710 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1711 } 1712 1713 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1714 } else if (!RetValExp && !FnRetType->isDependentType()) { 1715 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1716 // C99 6.8.6.4p1 (ext_ since GCC warns) 1717 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1718 1719 if (FunctionDecl *FD = getCurFunctionDecl()) 1720 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1721 else 1722 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1723 Result = new (Context) ReturnStmt(ReturnLoc); 1724 } else { 1725 const VarDecl *NRVOCandidate = 0; 1726 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1727 // we have a non-void function with an expression, continue checking 1728 1729 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1730 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1731 // function return. 1732 1733 // In C++ the return statement is handled via a copy initialization. 1734 // the C version of which boils down to CheckSingleAssignmentConstraints. 1735 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1736 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1737 FnRetType, 1738 NRVOCandidate != 0); 1739 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1740 FnRetType, RetValExp); 1741 if (Res.isInvalid()) { 1742 // FIXME: Cleanup temporaries here, anyway? 1743 return StmtError(); 1744 } 1745 1746 RetValExp = Res.takeAs<Expr>(); 1747 if (RetValExp) 1748 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1749 } 1750 1751 if (RetValExp) { 1752 CheckImplicitConversions(RetValExp, ReturnLoc); 1753 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1754 } 1755 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1756 } 1757 1758 // If we need to check for the named return value optimization, save the 1759 // return statement in our scope for later processing. 1760 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1761 !CurContext->isDependentContext()) 1762 FunctionScopes.back()->Returns.push_back(Result); 1763 1764 return Owned(Result); 1765} 1766 1767/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1768/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1769/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1770/// provide a strong guidance to not use it. 1771/// 1772/// This method checks to see if the argument is an acceptable l-value and 1773/// returns false if it is a case we can handle. 1774static bool CheckAsmLValue(const Expr *E, Sema &S) { 1775 // Type dependent expressions will be checked during instantiation. 1776 if (E->isTypeDependent()) 1777 return false; 1778 1779 if (E->isLValue()) 1780 return false; // Cool, this is an lvalue. 1781 1782 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1783 // are supposed to allow. 1784 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1785 if (E != E2 && E2->isLValue()) { 1786 if (!S.getLangOptions().HeinousExtensions) 1787 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1788 << E->getSourceRange(); 1789 else 1790 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1791 << E->getSourceRange(); 1792 // Accept, even if we emitted an error diagnostic. 1793 return false; 1794 } 1795 1796 // None of the above, just randomly invalid non-lvalue. 1797 return true; 1798} 1799 1800/// isOperandMentioned - Return true if the specified operand # is mentioned 1801/// anywhere in the decomposed asm string. 1802static bool isOperandMentioned(unsigned OpNo, 1803 llvm::ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 1804 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 1805 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 1806 if (!Piece.isOperand()) continue; 1807 1808 // If this is a reference to the input and if the input was the smaller 1809 // one, then we have to reject this asm. 1810 if (Piece.getOperandNo() == OpNo) 1811 return true; 1812 } 1813 1814 return false; 1815} 1816 1817StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 1818 bool IsVolatile, unsigned NumOutputs, 1819 unsigned NumInputs, IdentifierInfo **Names, 1820 MultiExprArg constraints, MultiExprArg exprs, 1821 Expr *asmString, MultiExprArg clobbers, 1822 SourceLocation RParenLoc, bool MSAsm) { 1823 unsigned NumClobbers = clobbers.size(); 1824 StringLiteral **Constraints = 1825 reinterpret_cast<StringLiteral**>(constraints.get()); 1826 Expr **Exprs = exprs.get(); 1827 StringLiteral *AsmString = cast<StringLiteral>(asmString); 1828 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1829 1830 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1831 1832 // The parser verifies that there is a string literal here. 1833 if (AsmString->isWide()) 1834 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1835 << AsmString->getSourceRange()); 1836 1837 for (unsigned i = 0; i != NumOutputs; i++) { 1838 StringLiteral *Literal = Constraints[i]; 1839 if (Literal->isWide()) 1840 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1841 << Literal->getSourceRange()); 1842 1843 llvm::StringRef OutputName; 1844 if (Names[i]) 1845 OutputName = Names[i]->getName(); 1846 1847 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1848 if (!Context.Target.validateOutputConstraint(Info)) 1849 return StmtError(Diag(Literal->getLocStart(), 1850 diag::err_asm_invalid_output_constraint) 1851 << Info.getConstraintStr()); 1852 1853 // Check that the output exprs are valid lvalues. 1854 Expr *OutputExpr = Exprs[i]; 1855 if (CheckAsmLValue(OutputExpr, *this)) { 1856 return StmtError(Diag(OutputExpr->getLocStart(), 1857 diag::err_asm_invalid_lvalue_in_output) 1858 << OutputExpr->getSourceRange()); 1859 } 1860 1861 OutputConstraintInfos.push_back(Info); 1862 } 1863 1864 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1865 1866 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1867 StringLiteral *Literal = Constraints[i]; 1868 if (Literal->isWide()) 1869 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1870 << Literal->getSourceRange()); 1871 1872 llvm::StringRef InputName; 1873 if (Names[i]) 1874 InputName = Names[i]->getName(); 1875 1876 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1877 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1878 NumOutputs, Info)) { 1879 return StmtError(Diag(Literal->getLocStart(), 1880 diag::err_asm_invalid_input_constraint) 1881 << Info.getConstraintStr()); 1882 } 1883 1884 Expr *InputExpr = Exprs[i]; 1885 1886 // Only allow void types for memory constraints. 1887 if (Info.allowsMemory() && !Info.allowsRegister()) { 1888 if (CheckAsmLValue(InputExpr, *this)) 1889 return StmtError(Diag(InputExpr->getLocStart(), 1890 diag::err_asm_invalid_lvalue_in_input) 1891 << Info.getConstraintStr() 1892 << InputExpr->getSourceRange()); 1893 } 1894 1895 if (Info.allowsRegister()) { 1896 if (InputExpr->getType()->isVoidType()) { 1897 return StmtError(Diag(InputExpr->getLocStart(), 1898 diag::err_asm_invalid_type_in_input) 1899 << InputExpr->getType() << Info.getConstraintStr() 1900 << InputExpr->getSourceRange()); 1901 } 1902 } 1903 1904 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 1905 if (Result.isInvalid()) 1906 return StmtError(); 1907 1908 Exprs[i] = Result.take(); 1909 InputConstraintInfos.push_back(Info); 1910 } 1911 1912 // Check that the clobbers are valid. 1913 for (unsigned i = 0; i != NumClobbers; i++) { 1914 StringLiteral *Literal = Clobbers[i]; 1915 if (Literal->isWide()) 1916 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1917 << Literal->getSourceRange()); 1918 1919 llvm::StringRef Clobber = Literal->getString(); 1920 1921 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1922 return StmtError(Diag(Literal->getLocStart(), 1923 diag::err_asm_unknown_register_name) << Clobber); 1924 } 1925 1926 AsmStmt *NS = 1927 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1928 NumOutputs, NumInputs, Names, Constraints, Exprs, 1929 AsmString, NumClobbers, Clobbers, RParenLoc); 1930 // Validate the asm string, ensuring it makes sense given the operands we 1931 // have. 1932 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1933 unsigned DiagOffs; 1934 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1935 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1936 << AsmString->getSourceRange(); 1937 return StmtError(); 1938 } 1939 1940 // Validate tied input operands for type mismatches. 1941 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1942 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1943 1944 // If this is a tied constraint, verify that the output and input have 1945 // either exactly the same type, or that they are int/ptr operands with the 1946 // same size (int/long, int*/long, are ok etc). 1947 if (!Info.hasTiedOperand()) continue; 1948 1949 unsigned TiedTo = Info.getTiedOperand(); 1950 unsigned InputOpNo = i+NumOutputs; 1951 Expr *OutputExpr = Exprs[TiedTo]; 1952 Expr *InputExpr = Exprs[InputOpNo]; 1953 QualType InTy = InputExpr->getType(); 1954 QualType OutTy = OutputExpr->getType(); 1955 if (Context.hasSameType(InTy, OutTy)) 1956 continue; // All types can be tied to themselves. 1957 1958 // Decide if the input and output are in the same domain (integer/ptr or 1959 // floating point. 1960 enum AsmDomain { 1961 AD_Int, AD_FP, AD_Other 1962 } InputDomain, OutputDomain; 1963 1964 if (InTy->isIntegerType() || InTy->isPointerType()) 1965 InputDomain = AD_Int; 1966 else if (InTy->isRealFloatingType()) 1967 InputDomain = AD_FP; 1968 else 1969 InputDomain = AD_Other; 1970 1971 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1972 OutputDomain = AD_Int; 1973 else if (OutTy->isRealFloatingType()) 1974 OutputDomain = AD_FP; 1975 else 1976 OutputDomain = AD_Other; 1977 1978 // They are ok if they are the same size and in the same domain. This 1979 // allows tying things like: 1980 // void* to int* 1981 // void* to int if they are the same size. 1982 // double to long double if they are the same size. 1983 // 1984 uint64_t OutSize = Context.getTypeSize(OutTy); 1985 uint64_t InSize = Context.getTypeSize(InTy); 1986 if (OutSize == InSize && InputDomain == OutputDomain && 1987 InputDomain != AD_Other) 1988 continue; 1989 1990 // If the smaller input/output operand is not mentioned in the asm string, 1991 // then we can promote the smaller one to a larger input and the asm string 1992 // won't notice. 1993 bool SmallerValueMentioned = false; 1994 1995 // If this is a reference to the input and if the input was the smaller 1996 // one, then we have to reject this asm. 1997 if (isOperandMentioned(InputOpNo, Pieces)) { 1998 // This is a use in the asm string of the smaller operand. Since we 1999 // codegen this by promoting to a wider value, the asm will get printed 2000 // "wrong". 2001 SmallerValueMentioned |= InSize < OutSize; 2002 } 2003 if (isOperandMentioned(TiedTo, Pieces)) { 2004 // If this is a reference to the output, and if the output is the larger 2005 // value, then it's ok because we'll promote the input to the larger type. 2006 SmallerValueMentioned |= OutSize < InSize; 2007 } 2008 2009 // If the smaller value wasn't mentioned in the asm string, and if the 2010 // output was a register, just extend the shorter one to the size of the 2011 // larger one. 2012 if (!SmallerValueMentioned && InputDomain != AD_Other && 2013 OutputConstraintInfos[TiedTo].allowsRegister()) 2014 continue; 2015 2016 // Either both of the operands were mentioned or the smaller one was 2017 // mentioned. One more special case that we'll allow: if the tied input is 2018 // integer, unmentioned, and is a constant, then we'll allow truncating it 2019 // down to the size of the destination. 2020 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2021 !isOperandMentioned(InputOpNo, Pieces) && 2022 InputExpr->isEvaluatable(Context)) { 2023 InputExpr = ImpCastExprToType(InputExpr, OutTy, CK_IntegralCast).take(); 2024 Exprs[InputOpNo] = InputExpr; 2025 NS->setInputExpr(i, InputExpr); 2026 continue; 2027 } 2028 2029 Diag(InputExpr->getLocStart(), 2030 diag::err_asm_tying_incompatible_types) 2031 << InTy << OutTy << OutputExpr->getSourceRange() 2032 << InputExpr->getSourceRange(); 2033 return StmtError(); 2034 } 2035 2036 return Owned(NS); 2037} 2038 2039StmtResult 2040Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2041 SourceLocation RParen, Decl *Parm, 2042 Stmt *Body) { 2043 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2044 if (Var && Var->isInvalidDecl()) 2045 return StmtError(); 2046 2047 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2048} 2049 2050StmtResult 2051Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2052 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2053} 2054 2055StmtResult 2056Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2057 MultiStmtArg CatchStmts, Stmt *Finally) { 2058 if (!getLangOptions().ObjCExceptions) 2059 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2060 2061 getCurFunction()->setHasBranchProtectedScope(); 2062 unsigned NumCatchStmts = CatchStmts.size(); 2063 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2064 CatchStmts.release(), 2065 NumCatchStmts, 2066 Finally)); 2067} 2068 2069StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 2070 Expr *Throw) { 2071 if (Throw) { 2072 ExprResult Result = DefaultLvalueConversion(Throw); 2073 if (Result.isInvalid()) 2074 return StmtError(); 2075 2076 Throw = Result.take(); 2077 QualType ThrowType = Throw->getType(); 2078 // Make sure the expression type is an ObjC pointer or "void *". 2079 if (!ThrowType->isDependentType() && 2080 !ThrowType->isObjCObjectPointerType()) { 2081 const PointerType *PT = ThrowType->getAs<PointerType>(); 2082 if (!PT || !PT->getPointeeType()->isVoidType()) 2083 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2084 << Throw->getType() << Throw->getSourceRange()); 2085 } 2086 } 2087 2088 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2089} 2090 2091StmtResult 2092Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2093 Scope *CurScope) { 2094 if (!getLangOptions().ObjCExceptions) 2095 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2096 2097 if (!Throw) { 2098 // @throw without an expression designates a rethrow (which much occur 2099 // in the context of an @catch clause). 2100 Scope *AtCatchParent = CurScope; 2101 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2102 AtCatchParent = AtCatchParent->getParent(); 2103 if (!AtCatchParent) 2104 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2105 } 2106 2107 return BuildObjCAtThrowStmt(AtLoc, Throw); 2108} 2109 2110StmtResult 2111Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2112 Stmt *SyncBody) { 2113 getCurFunction()->setHasBranchProtectedScope(); 2114 2115 ExprResult Result = DefaultLvalueConversion(SyncExpr); 2116 if (Result.isInvalid()) 2117 return StmtError(); 2118 2119 SyncExpr = Result.take(); 2120 // Make sure the expression type is an ObjC pointer or "void *". 2121 if (!SyncExpr->getType()->isDependentType() && 2122 !SyncExpr->getType()->isObjCObjectPointerType()) { 2123 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 2124 if (!PT || !PT->getPointeeType()->isVoidType()) 2125 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 2126 << SyncExpr->getType() << SyncExpr->getSourceRange()); 2127 } 2128 2129 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2130} 2131 2132/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2133/// and creates a proper catch handler from them. 2134StmtResult 2135Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2136 Stmt *HandlerBlock) { 2137 // There's nothing to test that ActOnExceptionDecl didn't already test. 2138 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2139 cast_or_null<VarDecl>(ExDecl), 2140 HandlerBlock)); 2141} 2142 2143namespace { 2144 2145class TypeWithHandler { 2146 QualType t; 2147 CXXCatchStmt *stmt; 2148public: 2149 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2150 : t(type), stmt(statement) {} 2151 2152 // An arbitrary order is fine as long as it places identical 2153 // types next to each other. 2154 bool operator<(const TypeWithHandler &y) const { 2155 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2156 return true; 2157 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2158 return false; 2159 else 2160 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2161 } 2162 2163 bool operator==(const TypeWithHandler& other) const { 2164 return t == other.t; 2165 } 2166 2167 CXXCatchStmt *getCatchStmt() const { return stmt; } 2168 SourceLocation getTypeSpecStartLoc() const { 2169 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2170 } 2171}; 2172 2173} 2174 2175/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2176/// handlers and creates a try statement from them. 2177StmtResult 2178Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2179 MultiStmtArg RawHandlers) { 2180 // Don't report an error if 'try' is used in system headers. 2181 if (!getLangOptions().CXXExceptions && 2182 !getSourceManager().isInSystemHeader(TryLoc)) 2183 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2184 2185 unsigned NumHandlers = RawHandlers.size(); 2186 assert(NumHandlers > 0 && 2187 "The parser shouldn't call this if there are no handlers."); 2188 Stmt **Handlers = RawHandlers.get(); 2189 2190 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2191 2192 for (unsigned i = 0; i < NumHandlers; ++i) { 2193 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 2194 if (!Handler->getExceptionDecl()) { 2195 if (i < NumHandlers - 1) 2196 return StmtError(Diag(Handler->getLocStart(), 2197 diag::err_early_catch_all)); 2198 2199 continue; 2200 } 2201 2202 const QualType CaughtType = Handler->getCaughtType(); 2203 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2204 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2205 } 2206 2207 // Detect handlers for the same type as an earlier one. 2208 if (NumHandlers > 1) { 2209 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2210 2211 TypeWithHandler prev = TypesWithHandlers[0]; 2212 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2213 TypeWithHandler curr = TypesWithHandlers[i]; 2214 2215 if (curr == prev) { 2216 Diag(curr.getTypeSpecStartLoc(), 2217 diag::warn_exception_caught_by_earlier_handler) 2218 << curr.getCatchStmt()->getCaughtType().getAsString(); 2219 Diag(prev.getTypeSpecStartLoc(), 2220 diag::note_previous_exception_handler) 2221 << prev.getCatchStmt()->getCaughtType().getAsString(); 2222 } 2223 2224 prev = curr; 2225 } 2226 } 2227 2228 getCurFunction()->setHasBranchProtectedScope(); 2229 2230 // FIXME: We should detect handlers that cannot catch anything because an 2231 // earlier handler catches a superclass. Need to find a method that is not 2232 // quadratic for this. 2233 // Neither of these are explicitly forbidden, but every compiler detects them 2234 // and warns. 2235 2236 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2237 Handlers, NumHandlers)); 2238} 2239