SemaStmt.cpp revision 4926d832aa2f0af9d7c00633727d49e7967eb978
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, 50 SourceLocation LeadingEmptyMacroLoc) { 51 return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacroLoc)); 52} 53 54StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 55 SourceLocation EndLoc) { 56 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 57 58 // If we have an invalid decl, just return an error. 59 if (DG.isNull()) return StmtError(); 60 61 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 62} 63 64void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 65 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 66 67 // If we have an invalid decl, just return. 68 if (DG.isNull() || !DG.isSingleDecl()) return; 69 // suppress any potential 'unused variable' warning. 70 DG.getSingleDecl()->setUsed(); 71} 72 73void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 74 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 75 return DiagnoseUnusedExprResult(Label->getSubStmt()); 76 77 const Expr *E = dyn_cast_or_null<Expr>(S); 78 if (!E) 79 return; 80 81 SourceLocation Loc; 82 SourceRange R1, R2; 83 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 84 return; 85 86 // Okay, we have an unused result. Depending on what the base expression is, 87 // we might want to make a more specific diagnostic. Check for one of these 88 // cases now. 89 unsigned DiagID = diag::warn_unused_expr; 90 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 91 E = Temps->getSubExpr(); 92 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 93 E = TempExpr->getSubExpr(); 94 95 E = E->IgnoreParenImpCasts(); 96 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 97 if (E->getType()->isVoidType()) 98 return; 99 100 // If the callee has attribute pure, const, or warn_unused_result, warn with 101 // a more specific message to make it clear what is happening. 102 if (const Decl *FD = CE->getCalleeDecl()) { 103 if (FD->getAttr<WarnUnusedResultAttr>()) { 104 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 105 return; 106 } 107 if (FD->getAttr<PureAttr>()) { 108 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 109 return; 110 } 111 if (FD->getAttr<ConstAttr>()) { 112 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 113 return; 114 } 115 } 116 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 117 const ObjCMethodDecl *MD = ME->getMethodDecl(); 118 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 119 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 120 return; 121 } 122 } else if (isa<ObjCPropertyRefExpr>(E)) { 123 DiagID = diag::warn_unused_property_expr; 124 } else if (const CXXFunctionalCastExpr *FC 125 = dyn_cast<CXXFunctionalCastExpr>(E)) { 126 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 127 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 128 return; 129 } 130 // Diagnose "(void*) blah" as a typo for "(void) blah". 131 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 132 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 133 QualType T = TI->getType(); 134 135 // We really do want to use the non-canonical type here. 136 if (T == Context.VoidPtrTy) { 137 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 138 139 Diag(Loc, diag::warn_unused_voidptr) 140 << FixItHint::CreateRemoval(TL.getStarLoc()); 141 return; 142 } 143 } 144 145 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 146} 147 148StmtResult 149Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 150 MultiStmtArg elts, bool isStmtExpr) { 151 unsigned NumElts = elts.size(); 152 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 153 // If we're in C89 mode, check that we don't have any decls after stmts. If 154 // so, emit an extension diagnostic. 155 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 156 // Note that __extension__ can be around a decl. 157 unsigned i = 0; 158 // Skip over all declarations. 159 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 160 /*empty*/; 161 162 // We found the end of the list or a statement. Scan for another declstmt. 163 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 164 /*empty*/; 165 166 if (i != NumElts) { 167 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 168 Diag(D->getLocation(), diag::ext_mixed_decls_code); 169 } 170 } 171 // Warn about unused expressions in statements. 172 for (unsigned i = 0; i != NumElts; ++i) { 173 // Ignore statements that are last in a statement expression. 174 if (isStmtExpr && i == NumElts - 1) 175 continue; 176 177 DiagnoseUnusedExprResult(Elts[i]); 178 } 179 180 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 181} 182 183StmtResult 184Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 185 SourceLocation DotDotDotLoc, Expr *RHSVal, 186 SourceLocation ColonLoc) { 187 assert((LHSVal != 0) && "missing expression in case statement"); 188 189 // C99 6.8.4.2p3: The expression shall be an integer constant. 190 // However, GCC allows any evaluatable integer expression. 191 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 192 VerifyIntegerConstantExpression(LHSVal)) 193 return StmtError(); 194 195 // GCC extension: The expression shall be an integer constant. 196 197 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 198 VerifyIntegerConstantExpression(RHSVal)) { 199 RHSVal = 0; // Recover by just forgetting about it. 200 } 201 202 if (getCurFunction()->SwitchStack.empty()) { 203 Diag(CaseLoc, diag::err_case_not_in_switch); 204 return StmtError(); 205 } 206 207 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 208 ColonLoc); 209 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 210 return Owned(CS); 211} 212 213/// ActOnCaseStmtBody - This installs a statement as the body of a case. 214void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 215 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 216 CS->setSubStmt(SubStmt); 217} 218 219StmtResult 220Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 221 Stmt *SubStmt, Scope *CurScope) { 222 if (getCurFunction()->SwitchStack.empty()) { 223 Diag(DefaultLoc, diag::err_default_not_in_switch); 224 return Owned(SubStmt); 225 } 226 227 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 228 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 229 return Owned(DS); 230} 231 232StmtResult 233Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 234 SourceLocation ColonLoc, Stmt *SubStmt) { 235 236 // If the label was multiply defined, reject it now. 237 if (TheDecl->getStmt()) { 238 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 239 Diag(TheDecl->getLocation(), diag::note_previous_definition); 240 return Owned(SubStmt); 241 } 242 243 // Otherwise, things are good. Fill in the declaration and return it. 244 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 245 TheDecl->setStmt(LS); 246 if (!TheDecl->isGnuLocal()) 247 TheDecl->setLocation(IdentLoc); 248 return Owned(LS); 249} 250 251StmtResult 252Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 253 Stmt *thenStmt, SourceLocation ElseLoc, 254 Stmt *elseStmt) { 255 ExprResult CondResult(CondVal.release()); 256 257 VarDecl *ConditionVar = 0; 258 if (CondVar) { 259 ConditionVar = cast<VarDecl>(CondVar); 260 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 261 if (CondResult.isInvalid()) 262 return StmtError(); 263 } 264 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 265 if (!ConditionExpr) 266 return StmtError(); 267 268 DiagnoseUnusedExprResult(thenStmt); 269 270 // Warn if the if block has a null body without an else value. 271 // this helps prevent bugs due to typos, such as 272 // if (condition); 273 // do_stuff(); 274 // 275 if (!elseStmt) { 276 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 277 // But do not warn if the body is a macro that expands to nothing, e.g: 278 // 279 // #define CALL(x) 280 // if (condition) 281 // CALL(0); 282 // 283 if (!stmt->hasLeadingEmptyMacro()) 284 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 285 } 286 287 DiagnoseUnusedExprResult(elseStmt); 288 289 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 290 thenStmt, ElseLoc, elseStmt)); 291} 292 293/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 294/// the specified width and sign. If an overflow occurs, detect it and emit 295/// the specified diagnostic. 296void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 297 unsigned NewWidth, bool NewSign, 298 SourceLocation Loc, 299 unsigned DiagID) { 300 // Perform a conversion to the promoted condition type if needed. 301 if (NewWidth > Val.getBitWidth()) { 302 // If this is an extension, just do it. 303 Val = Val.extend(NewWidth); 304 Val.setIsSigned(NewSign); 305 306 // If the input was signed and negative and the output is 307 // unsigned, don't bother to warn: this is implementation-defined 308 // behavior. 309 // FIXME: Introduce a second, default-ignored warning for this case? 310 } else if (NewWidth < Val.getBitWidth()) { 311 // If this is a truncation, check for overflow. 312 llvm::APSInt ConvVal(Val); 313 ConvVal = ConvVal.trunc(NewWidth); 314 ConvVal.setIsSigned(NewSign); 315 ConvVal = ConvVal.extend(Val.getBitWidth()); 316 ConvVal.setIsSigned(Val.isSigned()); 317 if (ConvVal != Val) 318 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 319 320 // Regardless of whether a diagnostic was emitted, really do the 321 // truncation. 322 Val = Val.trunc(NewWidth); 323 Val.setIsSigned(NewSign); 324 } else if (NewSign != Val.isSigned()) { 325 // Convert the sign to match the sign of the condition. This can cause 326 // overflow as well: unsigned(INTMIN) 327 // We don't diagnose this overflow, because it is implementation-defined 328 // behavior. 329 // FIXME: Introduce a second, default-ignored warning for this case? 330 llvm::APSInt OldVal(Val); 331 Val.setIsSigned(NewSign); 332 } 333} 334 335namespace { 336 struct CaseCompareFunctor { 337 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 338 const llvm::APSInt &RHS) { 339 return LHS.first < RHS; 340 } 341 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 342 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 343 return LHS.first < RHS.first; 344 } 345 bool operator()(const llvm::APSInt &LHS, 346 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 347 return LHS < RHS.first; 348 } 349 }; 350} 351 352/// CmpCaseVals - Comparison predicate for sorting case values. 353/// 354static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 355 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 356 if (lhs.first < rhs.first) 357 return true; 358 359 if (lhs.first == rhs.first && 360 lhs.second->getCaseLoc().getRawEncoding() 361 < rhs.second->getCaseLoc().getRawEncoding()) 362 return true; 363 return false; 364} 365 366/// CmpEnumVals - Comparison predicate for sorting enumeration values. 367/// 368static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 369 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 370{ 371 return lhs.first < rhs.first; 372} 373 374/// EqEnumVals - Comparison preficate for uniqing enumeration values. 375/// 376static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 377 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 378{ 379 return lhs.first == rhs.first; 380} 381 382/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 383/// potentially integral-promoted expression @p expr. 384static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 385 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 386 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 387 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 388 if (TypeBeforePromotion->isIntegralOrEnumerationType()) { 389 return TypeBeforePromotion; 390 } 391 } 392 return expr->getType(); 393} 394 395StmtResult 396Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 397 Decl *CondVar) { 398 ExprResult CondResult; 399 400 VarDecl *ConditionVar = 0; 401 if (CondVar) { 402 ConditionVar = cast<VarDecl>(CondVar); 403 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 404 if (CondResult.isInvalid()) 405 return StmtError(); 406 407 Cond = CondResult.release(); 408 } 409 410 if (!Cond) 411 return StmtError(); 412 413 CondResult 414 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 415 PDiag(diag::err_typecheck_statement_requires_integer), 416 PDiag(diag::err_switch_incomplete_class_type) 417 << Cond->getSourceRange(), 418 PDiag(diag::err_switch_explicit_conversion), 419 PDiag(diag::note_switch_conversion), 420 PDiag(diag::err_switch_multiple_conversions), 421 PDiag(diag::note_switch_conversion), 422 PDiag(0)); 423 if (CondResult.isInvalid()) return StmtError(); 424 Cond = CondResult.take(); 425 426 if (!CondVar) { 427 CheckImplicitConversions(Cond, SwitchLoc); 428 CondResult = MaybeCreateExprWithCleanups(Cond); 429 if (CondResult.isInvalid()) 430 return StmtError(); 431 Cond = CondResult.take(); 432 } 433 434 getCurFunction()->setHasBranchIntoScope(); 435 436 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 437 getCurFunction()->SwitchStack.push_back(SS); 438 return Owned(SS); 439} 440 441static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 442 if (Val.getBitWidth() < BitWidth) 443 Val = Val.extend(BitWidth); 444 else if (Val.getBitWidth() > BitWidth) 445 Val = Val.trunc(BitWidth); 446 Val.setIsSigned(IsSigned); 447} 448 449StmtResult 450Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 451 Stmt *BodyStmt) { 452 SwitchStmt *SS = cast<SwitchStmt>(Switch); 453 assert(SS == getCurFunction()->SwitchStack.back() && 454 "switch stack missing push/pop!"); 455 456 SS->setBody(BodyStmt, SwitchLoc); 457 getCurFunction()->SwitchStack.pop_back(); 458 459 if (SS->getCond() == 0) 460 return StmtError(); 461 462 Expr *CondExpr = SS->getCond(); 463 Expr *CondExprBeforePromotion = CondExpr; 464 QualType CondTypeBeforePromotion = 465 GetTypeBeforeIntegralPromotion(CondExpr); 466 467 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 468 ExprResult CondResult = UsualUnaryConversions(CondExpr); 469 if (CondResult.isInvalid()) 470 return StmtError(); 471 CondExpr = CondResult.take(); 472 QualType CondType = CondExpr->getType(); 473 SS->setCond(CondExpr); 474 475 // C++ 6.4.2.p2: 476 // Integral promotions are performed (on the switch condition). 477 // 478 // A case value unrepresentable by the original switch condition 479 // type (before the promotion) doesn't make sense, even when it can 480 // be represented by the promoted type. Therefore we need to find 481 // the pre-promotion type of the switch condition. 482 if (!CondExpr->isTypeDependent()) { 483 // We have already converted the expression to an integral or enumeration 484 // type, when we started the switch statement. If we don't have an 485 // appropriate type now, just return an error. 486 if (!CondType->isIntegralOrEnumerationType()) 487 return StmtError(); 488 489 if (CondExpr->isKnownToHaveBooleanValue()) { 490 // switch(bool_expr) {...} is often a programmer error, e.g. 491 // switch(n && mask) { ... } // Doh - should be "n & mask". 492 // One can always use an if statement instead of switch(bool_expr). 493 Diag(SwitchLoc, diag::warn_bool_switch_condition) 494 << CondExpr->getSourceRange(); 495 } 496 } 497 498 // Get the bitwidth of the switched-on value before promotions. We must 499 // convert the integer case values to this width before comparison. 500 bool HasDependentValue 501 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 502 unsigned CondWidth 503 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 504 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 505 506 // Accumulate all of the case values in a vector so that we can sort them 507 // and detect duplicates. This vector contains the APInt for the case after 508 // it has been converted to the condition type. 509 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 510 CaseValsTy CaseVals; 511 512 // Keep track of any GNU case ranges we see. The APSInt is the low value. 513 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 514 CaseRangesTy CaseRanges; 515 516 DefaultStmt *TheDefaultStmt = 0; 517 518 bool CaseListIsErroneous = false; 519 520 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 521 SC = SC->getNextSwitchCase()) { 522 523 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 524 if (TheDefaultStmt) { 525 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 526 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 527 528 // FIXME: Remove the default statement from the switch block so that 529 // we'll return a valid AST. This requires recursing down the AST and 530 // finding it, not something we are set up to do right now. For now, 531 // just lop the entire switch stmt out of the AST. 532 CaseListIsErroneous = true; 533 } 534 TheDefaultStmt = DS; 535 536 } else { 537 CaseStmt *CS = cast<CaseStmt>(SC); 538 539 // We already verified that the expression has a i-c-e value (C99 540 // 6.8.4.2p3) - get that value now. 541 Expr *Lo = CS->getLHS(); 542 543 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 544 HasDependentValue = true; 545 break; 546 } 547 548 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 549 550 // Convert the value to the same width/sign as the condition. 551 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 552 Lo->getLocStart(), 553 diag::warn_case_value_overflow); 554 555 // If the LHS is not the same type as the condition, insert an implicit 556 // cast. 557 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 558 CS->setLHS(Lo); 559 560 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 561 if (CS->getRHS()) { 562 if (CS->getRHS()->isTypeDependent() || 563 CS->getRHS()->isValueDependent()) { 564 HasDependentValue = true; 565 break; 566 } 567 CaseRanges.push_back(std::make_pair(LoVal, CS)); 568 } else 569 CaseVals.push_back(std::make_pair(LoVal, CS)); 570 } 571 } 572 573 if (!HasDependentValue) { 574 // If we don't have a default statement, check whether the 575 // condition is constant. 576 llvm::APSInt ConstantCondValue; 577 bool HasConstantCond = false; 578 bool ShouldCheckConstantCond = false; 579 if (!HasDependentValue && !TheDefaultStmt) { 580 Expr::EvalResult Result; 581 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 582 if (HasConstantCond) { 583 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 584 ConstantCondValue = Result.Val.getInt(); 585 ShouldCheckConstantCond = true; 586 587 assert(ConstantCondValue.getBitWidth() == CondWidth && 588 ConstantCondValue.isSigned() == CondIsSigned); 589 } 590 } 591 592 // Sort all the scalar case values so we can easily detect duplicates. 593 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 594 595 if (!CaseVals.empty()) { 596 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 597 if (ShouldCheckConstantCond && 598 CaseVals[i].first == ConstantCondValue) 599 ShouldCheckConstantCond = false; 600 601 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 602 // If we have a duplicate, report it. 603 Diag(CaseVals[i].second->getLHS()->getLocStart(), 604 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 605 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 606 diag::note_duplicate_case_prev); 607 // FIXME: We really want to remove the bogus case stmt from the 608 // substmt, but we have no way to do this right now. 609 CaseListIsErroneous = true; 610 } 611 } 612 } 613 614 // Detect duplicate case ranges, which usually don't exist at all in 615 // the first place. 616 if (!CaseRanges.empty()) { 617 // Sort all the case ranges by their low value so we can easily detect 618 // overlaps between ranges. 619 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 620 621 // Scan the ranges, computing the high values and removing empty ranges. 622 std::vector<llvm::APSInt> HiVals; 623 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 624 llvm::APSInt &LoVal = CaseRanges[i].first; 625 CaseStmt *CR = CaseRanges[i].second; 626 Expr *Hi = CR->getRHS(); 627 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 628 629 // Convert the value to the same width/sign as the condition. 630 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 631 Hi->getLocStart(), 632 diag::warn_case_value_overflow); 633 634 // If the LHS is not the same type as the condition, insert an implicit 635 // cast. 636 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 637 CR->setRHS(Hi); 638 639 // If the low value is bigger than the high value, the case is empty. 640 if (LoVal > HiVal) { 641 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 642 << SourceRange(CR->getLHS()->getLocStart(), 643 Hi->getLocEnd()); 644 CaseRanges.erase(CaseRanges.begin()+i); 645 --i, --e; 646 continue; 647 } 648 649 if (ShouldCheckConstantCond && 650 LoVal <= ConstantCondValue && 651 ConstantCondValue <= HiVal) 652 ShouldCheckConstantCond = false; 653 654 HiVals.push_back(HiVal); 655 } 656 657 // Rescan the ranges, looking for overlap with singleton values and other 658 // ranges. Since the range list is sorted, we only need to compare case 659 // ranges with their neighbors. 660 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 661 llvm::APSInt &CRLo = CaseRanges[i].first; 662 llvm::APSInt &CRHi = HiVals[i]; 663 CaseStmt *CR = CaseRanges[i].second; 664 665 // Check to see whether the case range overlaps with any 666 // singleton cases. 667 CaseStmt *OverlapStmt = 0; 668 llvm::APSInt OverlapVal(32); 669 670 // Find the smallest value >= the lower bound. If I is in the 671 // case range, then we have overlap. 672 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 673 CaseVals.end(), CRLo, 674 CaseCompareFunctor()); 675 if (I != CaseVals.end() && I->first < CRHi) { 676 OverlapVal = I->first; // Found overlap with scalar. 677 OverlapStmt = I->second; 678 } 679 680 // Find the smallest value bigger than the upper bound. 681 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 682 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 683 OverlapVal = (I-1)->first; // Found overlap with scalar. 684 OverlapStmt = (I-1)->second; 685 } 686 687 // Check to see if this case stmt overlaps with the subsequent 688 // case range. 689 if (i && CRLo <= HiVals[i-1]) { 690 OverlapVal = HiVals[i-1]; // Found overlap with range. 691 OverlapStmt = CaseRanges[i-1].second; 692 } 693 694 if (OverlapStmt) { 695 // If we have a duplicate, report it. 696 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 697 << OverlapVal.toString(10); 698 Diag(OverlapStmt->getLHS()->getLocStart(), 699 diag::note_duplicate_case_prev); 700 // FIXME: We really want to remove the bogus case stmt from the 701 // substmt, but we have no way to do this right now. 702 CaseListIsErroneous = true; 703 } 704 } 705 } 706 707 // Complain if we have a constant condition and we didn't find a match. 708 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 709 // TODO: it would be nice if we printed enums as enums, chars as 710 // chars, etc. 711 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 712 << ConstantCondValue.toString(10) 713 << CondExpr->getSourceRange(); 714 } 715 716 // Check to see if switch is over an Enum and handles all of its 717 // values. We only issue a warning if there is not 'default:', but 718 // we still do the analysis to preserve this information in the AST 719 // (which can be used by flow-based analyes). 720 // 721 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 722 723 // If switch has default case, then ignore it. 724 if (!CaseListIsErroneous && !HasConstantCond && ET) { 725 const EnumDecl *ED = ET->getDecl(); 726 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 727 EnumValsTy EnumVals; 728 729 // Gather all enum values, set their type and sort them, 730 // allowing easier comparison with CaseVals. 731 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 732 EDI != ED->enumerator_end(); ++EDI) { 733 llvm::APSInt Val = EDI->getInitVal(); 734 AdjustAPSInt(Val, CondWidth, CondIsSigned); 735 EnumVals.push_back(std::make_pair(Val, *EDI)); 736 } 737 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 738 EnumValsTy::iterator EIend = 739 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 740 741 // See which case values aren't in enum. 742 // TODO: we might want to check whether case values are out of the 743 // enum even if we don't want to check whether all cases are handled. 744 if (!TheDefaultStmt) { 745 EnumValsTy::const_iterator EI = EnumVals.begin(); 746 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 747 CI != CaseVals.end(); CI++) { 748 while (EI != EIend && EI->first < CI->first) 749 EI++; 750 if (EI == EIend || EI->first > CI->first) 751 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 752 << ED->getDeclName(); 753 } 754 // See which of case ranges aren't in enum 755 EI = EnumVals.begin(); 756 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 757 RI != CaseRanges.end() && EI != EIend; RI++) { 758 while (EI != EIend && EI->first < RI->first) 759 EI++; 760 761 if (EI == EIend || EI->first != RI->first) { 762 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 763 << ED->getDeclName(); 764 } 765 766 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 767 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 768 while (EI != EIend && EI->first < Hi) 769 EI++; 770 if (EI == EIend || EI->first != Hi) 771 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 772 << ED->getDeclName(); 773 } 774 } 775 776 // Check which enum vals aren't in switch 777 CaseValsTy::const_iterator CI = CaseVals.begin(); 778 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 779 bool hasCasesNotInSwitch = false; 780 781 llvm::SmallVector<DeclarationName,8> UnhandledNames; 782 783 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 784 // Drop unneeded case values 785 llvm::APSInt CIVal; 786 while (CI != CaseVals.end() && CI->first < EI->first) 787 CI++; 788 789 if (CI != CaseVals.end() && CI->first == EI->first) 790 continue; 791 792 // Drop unneeded case ranges 793 for (; RI != CaseRanges.end(); RI++) { 794 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 795 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 796 if (EI->first <= Hi) 797 break; 798 } 799 800 if (RI == CaseRanges.end() || EI->first < RI->first) { 801 hasCasesNotInSwitch = true; 802 if (!TheDefaultStmt) 803 UnhandledNames.push_back(EI->second->getDeclName()); 804 } 805 } 806 807 // Produce a nice diagnostic if multiple values aren't handled. 808 switch (UnhandledNames.size()) { 809 case 0: break; 810 case 1: 811 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 812 << UnhandledNames[0]; 813 break; 814 case 2: 815 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 816 << UnhandledNames[0] << UnhandledNames[1]; 817 break; 818 case 3: 819 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 820 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 821 break; 822 default: 823 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 824 << (unsigned)UnhandledNames.size() 825 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 826 break; 827 } 828 829 if (!hasCasesNotInSwitch) 830 SS->setAllEnumCasesCovered(); 831 } 832 } 833 834 // FIXME: If the case list was broken is some way, we don't have a good system 835 // to patch it up. Instead, just return the whole substmt as broken. 836 if (CaseListIsErroneous) 837 return StmtError(); 838 839 return Owned(SS); 840} 841 842StmtResult 843Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 844 Decl *CondVar, Stmt *Body) { 845 ExprResult CondResult(Cond.release()); 846 847 VarDecl *ConditionVar = 0; 848 if (CondVar) { 849 ConditionVar = cast<VarDecl>(CondVar); 850 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 851 if (CondResult.isInvalid()) 852 return StmtError(); 853 } 854 Expr *ConditionExpr = CondResult.take(); 855 if (!ConditionExpr) 856 return StmtError(); 857 858 DiagnoseUnusedExprResult(Body); 859 860 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 861 Body, WhileLoc)); 862} 863 864StmtResult 865Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 866 SourceLocation WhileLoc, SourceLocation CondLParen, 867 Expr *Cond, SourceLocation CondRParen) { 868 assert(Cond && "ActOnDoStmt(): missing expression"); 869 870 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 871 if (CondResult.isInvalid() || CondResult.isInvalid()) 872 return StmtError(); 873 Cond = CondResult.take(); 874 875 CheckImplicitConversions(Cond, DoLoc); 876 CondResult = MaybeCreateExprWithCleanups(Cond); 877 if (CondResult.isInvalid()) 878 return StmtError(); 879 Cond = CondResult.take(); 880 881 DiagnoseUnusedExprResult(Body); 882 883 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 884} 885 886StmtResult 887Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 888 Stmt *First, FullExprArg second, Decl *secondVar, 889 FullExprArg third, 890 SourceLocation RParenLoc, Stmt *Body) { 891 if (!getLangOptions().CPlusPlus) { 892 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 893 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 894 // declare identifiers for objects having storage class 'auto' or 895 // 'register'. 896 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 897 DI!=DE; ++DI) { 898 VarDecl *VD = dyn_cast<VarDecl>(*DI); 899 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 900 VD = 0; 901 if (VD == 0) 902 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 903 // FIXME: mark decl erroneous! 904 } 905 } 906 } 907 908 ExprResult SecondResult(second.release()); 909 VarDecl *ConditionVar = 0; 910 if (secondVar) { 911 ConditionVar = cast<VarDecl>(secondVar); 912 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 913 if (SecondResult.isInvalid()) 914 return StmtError(); 915 } 916 917 Expr *Third = third.release().takeAs<Expr>(); 918 919 DiagnoseUnusedExprResult(First); 920 DiagnoseUnusedExprResult(Third); 921 DiagnoseUnusedExprResult(Body); 922 923 return Owned(new (Context) ForStmt(Context, First, 924 SecondResult.take(), ConditionVar, 925 Third, Body, ForLoc, LParenLoc, 926 RParenLoc)); 927} 928 929/// In an Objective C collection iteration statement: 930/// for (x in y) 931/// x can be an arbitrary l-value expression. Bind it up as a 932/// full-expression. 933StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 934 CheckImplicitConversions(E); 935 ExprResult Result = MaybeCreateExprWithCleanups(E); 936 if (Result.isInvalid()) return StmtError(); 937 return Owned(static_cast<Stmt*>(Result.get())); 938} 939 940StmtResult 941Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 942 SourceLocation LParenLoc, 943 Stmt *First, Expr *Second, 944 SourceLocation RParenLoc, Stmt *Body) { 945 if (First) { 946 QualType FirstType; 947 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 948 if (!DS->isSingleDecl()) 949 return StmtError(Diag((*DS->decl_begin())->getLocation(), 950 diag::err_toomany_element_decls)); 951 952 Decl *D = DS->getSingleDecl(); 953 FirstType = cast<ValueDecl>(D)->getType(); 954 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 955 // declare identifiers for objects having storage class 'auto' or 956 // 'register'. 957 VarDecl *VD = cast<VarDecl>(D); 958 if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) 959 return StmtError(Diag(VD->getLocation(), 960 diag::err_non_variable_decl_in_for)); 961 } else { 962 Expr *FirstE = cast<Expr>(First); 963 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 964 return StmtError(Diag(First->getLocStart(), 965 diag::err_selector_element_not_lvalue) 966 << First->getSourceRange()); 967 968 FirstType = static_cast<Expr*>(First)->getType(); 969 } 970 if (!FirstType->isDependentType() && 971 !FirstType->isObjCObjectPointerType() && 972 !FirstType->isBlockPointerType()) 973 Diag(ForLoc, diag::err_selector_element_type) 974 << FirstType << First->getSourceRange(); 975 } 976 if (Second && !Second->isTypeDependent()) { 977 ExprResult Result = DefaultFunctionArrayLvalueConversion(Second); 978 if (Result.isInvalid()) 979 return StmtError(); 980 Second = Result.take(); 981 QualType SecondType = Second->getType(); 982 if (!SecondType->isObjCObjectPointerType()) 983 Diag(ForLoc, diag::err_collection_expr_type) 984 << SecondType << Second->getSourceRange(); 985 else if (const ObjCObjectPointerType *OPT = 986 SecondType->getAsObjCInterfacePointerType()) { 987 llvm::SmallVector<IdentifierInfo *, 4> KeyIdents; 988 IdentifierInfo* selIdent = 989 &Context.Idents.get("countByEnumeratingWithState"); 990 KeyIdents.push_back(selIdent); 991 selIdent = &Context.Idents.get("objects"); 992 KeyIdents.push_back(selIdent); 993 selIdent = &Context.Idents.get("count"); 994 KeyIdents.push_back(selIdent); 995 Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]); 996 if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) { 997 if (!IDecl->isForwardDecl() && 998 !IDecl->lookupInstanceMethod(CSelector) && 999 !LookupMethodInQualifiedType(CSelector, OPT, true)) { 1000 // Must further look into private implementation methods. 1001 if (!LookupPrivateInstanceMethod(CSelector, IDecl)) 1002 Diag(ForLoc, diag::warn_collection_expr_type) 1003 << SecondType << CSelector << Second->getSourceRange(); 1004 } 1005 } 1006 } 1007 } 1008 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1009 ForLoc, RParenLoc)); 1010} 1011 1012namespace { 1013 1014enum BeginEndFunction { 1015 BEF_begin, 1016 BEF_end 1017}; 1018 1019/// Build a variable declaration for a for-range statement. 1020static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1021 QualType Type, const char *Name) { 1022 DeclContext *DC = SemaRef.CurContext; 1023 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1024 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1025 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1026 TInfo, SC_Auto, SC_None); 1027 Decl->setImplicit(); 1028 return Decl; 1029} 1030 1031/// Finish building a variable declaration for a for-range statement. 1032/// \return true if an error occurs. 1033static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1034 SourceLocation Loc, int diag) { 1035 // Deduce the type for the iterator variable now rather than leaving it to 1036 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1037 TypeSourceInfo *InitTSI = 0; 1038 if (Init->getType()->isVoidType() || 1039 !SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI)) 1040 SemaRef.Diag(Loc, diag) << Init->getType(); 1041 if (!InitTSI) { 1042 Decl->setInvalidDecl(); 1043 return true; 1044 } 1045 Decl->setTypeSourceInfo(InitTSI); 1046 Decl->setType(InitTSI->getType()); 1047 1048 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1049 /*TypeMayContainAuto=*/false); 1050 SemaRef.FinalizeDeclaration(Decl); 1051 SemaRef.CurContext->addHiddenDecl(Decl); 1052 return false; 1053} 1054 1055/// Produce a note indicating which begin/end function was implicitly called 1056/// by a C++0x for-range statement. This is often not obvious from the code, 1057/// nor from the diagnostics produced when analysing the implicit expressions 1058/// required in a for-range statement. 1059void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1060 BeginEndFunction BEF) { 1061 CallExpr *CE = dyn_cast<CallExpr>(E); 1062 if (!CE) 1063 return; 1064 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1065 if (!D) 1066 return; 1067 SourceLocation Loc = D->getLocation(); 1068 1069 std::string Description; 1070 bool IsTemplate = false; 1071 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1072 Description = SemaRef.getTemplateArgumentBindingsText( 1073 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1074 IsTemplate = true; 1075 } 1076 1077 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1078 << BEF << IsTemplate << Description << E->getType(); 1079} 1080 1081/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1082/// given LookupResult is non-empty, it is assumed to describe a member which 1083/// will be invoked. Otherwise, the function will be found via argument 1084/// dependent lookup. 1085static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1086 SourceLocation Loc, 1087 VarDecl *Decl, 1088 BeginEndFunction BEF, 1089 const DeclarationNameInfo &NameInfo, 1090 LookupResult &MemberLookup, 1091 Expr *Range) { 1092 ExprResult CallExpr; 1093 if (!MemberLookup.empty()) { 1094 ExprResult MemberRef = 1095 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1096 /*IsPtr=*/false, CXXScopeSpec(), 1097 /*Qualifier=*/0, MemberLookup, 1098 /*TemplateArgs=*/0); 1099 if (MemberRef.isInvalid()) 1100 return ExprError(); 1101 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1102 Loc, 0); 1103 if (CallExpr.isInvalid()) 1104 return ExprError(); 1105 } else { 1106 UnresolvedSet<0> FoundNames; 1107 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1108 // std is an associated namespace. 1109 UnresolvedLookupExpr *Fn = 1110 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1111 NestedNameSpecifierLoc(), NameInfo, 1112 /*NeedsADL=*/true, /*Overloaded=*/false, 1113 FoundNames.begin(), FoundNames.end(), 1114 /*LookInStdNamespace=*/true); 1115 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1116 0); 1117 if (CallExpr.isInvalid()) { 1118 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1119 << Range->getType(); 1120 return ExprError(); 1121 } 1122 } 1123 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1124 diag::err_for_range_iter_deduction_failure)) { 1125 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1126 return ExprError(); 1127 } 1128 return CallExpr; 1129} 1130 1131} 1132 1133/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1134/// 1135/// C++0x [stmt.ranged]: 1136/// A range-based for statement is equivalent to 1137/// 1138/// { 1139/// auto && __range = range-init; 1140/// for ( auto __begin = begin-expr, 1141/// __end = end-expr; 1142/// __begin != __end; 1143/// ++__begin ) { 1144/// for-range-declaration = *__begin; 1145/// statement 1146/// } 1147/// } 1148/// 1149/// The body of the loop is not available yet, since it cannot be analysed until 1150/// we have determined the type of the for-range-declaration. 1151StmtResult 1152Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1153 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1154 SourceLocation RParenLoc) { 1155 if (!First || !Range) 1156 return StmtError(); 1157 1158 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1159 assert(DS && "first part of for range not a decl stmt"); 1160 1161 if (!DS->isSingleDecl()) { 1162 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1163 return StmtError(); 1164 } 1165 if (DS->getSingleDecl()->isInvalidDecl()) 1166 return StmtError(); 1167 1168 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1169 return StmtError(); 1170 1171 // Build auto && __range = range-init 1172 SourceLocation RangeLoc = Range->getLocStart(); 1173 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1174 Context.getAutoRRefDeductType(), 1175 "__range"); 1176 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1177 diag::err_for_range_deduction_failure)) 1178 return StmtError(); 1179 1180 // Claim the type doesn't contain auto: we've already done the checking. 1181 DeclGroupPtrTy RangeGroup = 1182 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1183 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1184 if (RangeDecl.isInvalid()) 1185 return StmtError(); 1186 1187 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1188 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1189 RParenLoc); 1190} 1191 1192/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1193StmtResult 1194Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1195 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1196 Expr *Inc, Stmt *LoopVarDecl, 1197 SourceLocation RParenLoc) { 1198 Scope *S = getCurScope(); 1199 1200 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1201 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1202 QualType RangeVarType = RangeVar->getType(); 1203 1204 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1205 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1206 1207 StmtResult BeginEndDecl = BeginEnd; 1208 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1209 1210 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1211 SourceLocation RangeLoc = RangeVar->getLocation(); 1212 1213 ExprResult RangeRef = BuildDeclRefExpr(RangeVar, 1214 RangeVarType.getNonReferenceType(), 1215 VK_LValue, ColonLoc); 1216 if (RangeRef.isInvalid()) 1217 return StmtError(); 1218 1219 QualType AutoType = Context.getAutoDeductType(); 1220 Expr *Range = RangeVar->getInit(); 1221 if (!Range) 1222 return StmtError(); 1223 QualType RangeType = Range->getType(); 1224 1225 if (RequireCompleteType(RangeLoc, RangeType, 1226 PDiag(diag::err_for_range_incomplete_type))) 1227 return StmtError(); 1228 1229 // Build auto __begin = begin-expr, __end = end-expr. 1230 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1231 "__begin"); 1232 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1233 "__end"); 1234 1235 // Build begin-expr and end-expr and attach to __begin and __end variables. 1236 ExprResult BeginExpr, EndExpr; 1237 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1238 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1239 // __range + __bound, respectively, where __bound is the array bound. If 1240 // _RangeT is an array of unknown size or an array of incomplete type, 1241 // the program is ill-formed; 1242 1243 // begin-expr is __range. 1244 BeginExpr = RangeRef; 1245 if (FinishForRangeVarDecl(*this, BeginVar, RangeRef.get(), ColonLoc, 1246 diag::err_for_range_iter_deduction_failure)) { 1247 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1248 return StmtError(); 1249 } 1250 1251 // Find the array bound. 1252 ExprResult BoundExpr; 1253 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1254 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1255 Context.getPointerDiffType(), 1256 RangeLoc)); 1257 else if (const VariableArrayType *VAT = 1258 dyn_cast<VariableArrayType>(UnqAT)) 1259 BoundExpr = VAT->getSizeExpr(); 1260 else { 1261 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1262 // UnqAT is not incomplete and Range is not type-dependent. 1263 assert(0 && "Unexpected array type in for-range"); 1264 return StmtError(); 1265 } 1266 1267 // end-expr is __range + __bound. 1268 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, RangeRef.get(), 1269 BoundExpr.get()); 1270 if (EndExpr.isInvalid()) 1271 return StmtError(); 1272 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1273 diag::err_for_range_iter_deduction_failure)) { 1274 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1275 return StmtError(); 1276 } 1277 } else { 1278 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1279 ColonLoc); 1280 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1281 ColonLoc); 1282 1283 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1284 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1285 1286 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1287 // - if _RangeT is a class type, the unqualified-ids begin and end are 1288 // looked up in the scope of class _RangeT as if by class member access 1289 // lookup (3.4.5), and if either (or both) finds at least one 1290 // declaration, begin-expr and end-expr are __range.begin() and 1291 // __range.end(), respectively; 1292 LookupQualifiedName(BeginMemberLookup, D); 1293 LookupQualifiedName(EndMemberLookup, D); 1294 1295 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1296 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1297 << RangeType << BeginMemberLookup.empty(); 1298 return StmtError(); 1299 } 1300 } else { 1301 // - otherwise, begin-expr and end-expr are begin(__range) and 1302 // end(__range), respectively, where begin and end are looked up with 1303 // argument-dependent lookup (3.4.2). For the purposes of this name 1304 // lookup, namespace std is an associated namespace. 1305 } 1306 1307 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1308 BEF_begin, BeginNameInfo, 1309 BeginMemberLookup, RangeRef.get()); 1310 if (BeginExpr.isInvalid()) 1311 return StmtError(); 1312 1313 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1314 BEF_end, EndNameInfo, 1315 EndMemberLookup, RangeRef.get()); 1316 if (EndExpr.isInvalid()) 1317 return StmtError(); 1318 } 1319 1320 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1321 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1322 if (!Context.hasSameType(BeginType, EndType)) { 1323 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1324 << BeginType << EndType; 1325 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1326 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1327 } 1328 1329 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1330 // Claim the type doesn't contain auto: we've already done the checking. 1331 DeclGroupPtrTy BeginEndGroup = 1332 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1333 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1334 1335 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, 1336 BeginType.getNonReferenceType(), 1337 VK_LValue, ColonLoc); 1338 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1339 VK_LValue, ColonLoc); 1340 1341 // Build and check __begin != __end expression. 1342 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1343 BeginRef.get(), EndRef.get()); 1344 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1345 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1346 if (NotEqExpr.isInvalid()) { 1347 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1348 if (!Context.hasSameType(BeginType, EndType)) 1349 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1350 return StmtError(); 1351 } 1352 1353 // Build and check ++__begin expression. 1354 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1355 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1356 if (IncrExpr.isInvalid()) { 1357 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1358 return StmtError(); 1359 } 1360 1361 // Build and check *__begin expression. 1362 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1363 if (DerefExpr.isInvalid()) { 1364 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1365 return StmtError(); 1366 } 1367 1368 // Attach *__begin as initializer for VD. 1369 if (!LoopVar->isInvalidDecl()) { 1370 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1371 /*TypeMayContainAuto=*/true); 1372 if (LoopVar->isInvalidDecl()) 1373 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1374 } 1375 } 1376 1377 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1378 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1379 NotEqExpr.take(), IncrExpr.take(), 1380 LoopVarDS, /*Body=*/0, ForLoc, 1381 ColonLoc, RParenLoc)); 1382} 1383 1384/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1385/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1386/// body cannot be performed until after the type of the range variable is 1387/// determined. 1388StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1389 if (!S || !B) 1390 return StmtError(); 1391 1392 cast<CXXForRangeStmt>(S)->setBody(B); 1393 return S; 1394} 1395 1396StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1397 SourceLocation LabelLoc, 1398 LabelDecl *TheDecl) { 1399 getCurFunction()->setHasBranchIntoScope(); 1400 TheDecl->setUsed(); 1401 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1402} 1403 1404StmtResult 1405Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1406 Expr *E) { 1407 // Convert operand to void* 1408 if (!E->isTypeDependent()) { 1409 QualType ETy = E->getType(); 1410 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1411 ExprResult ExprRes = Owned(E); 1412 AssignConvertType ConvTy = 1413 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1414 if (ExprRes.isInvalid()) 1415 return StmtError(); 1416 E = ExprRes.take(); 1417 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1418 return StmtError(); 1419 } 1420 1421 getCurFunction()->setHasIndirectGoto(); 1422 1423 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1424} 1425 1426StmtResult 1427Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1428 Scope *S = CurScope->getContinueParent(); 1429 if (!S) { 1430 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1431 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1432 } 1433 1434 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1435} 1436 1437StmtResult 1438Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1439 Scope *S = CurScope->getBreakParent(); 1440 if (!S) { 1441 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1442 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1443 } 1444 1445 return Owned(new (Context) BreakStmt(BreakLoc)); 1446} 1447 1448/// \brief Determine whether the given expression is a candidate for 1449/// copy elision in either a return statement or a throw expression. 1450/// 1451/// \param ReturnType If we're determining the copy elision candidate for 1452/// a return statement, this is the return type of the function. If we're 1453/// determining the copy elision candidate for a throw expression, this will 1454/// be a NULL type. 1455/// 1456/// \param E The expression being returned from the function or block, or 1457/// being thrown. 1458/// 1459/// \param AllowFunctionParameter Whether we allow function parameters to 1460/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1461/// we re-use this logic to determine whether we should try to move as part of 1462/// a return or throw (which does allow function parameters). 1463/// 1464/// \returns The NRVO candidate variable, if the return statement may use the 1465/// NRVO, or NULL if there is no such candidate. 1466const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1467 Expr *E, 1468 bool AllowFunctionParameter) { 1469 QualType ExprType = E->getType(); 1470 // - in a return statement in a function with ... 1471 // ... a class return type ... 1472 if (!ReturnType.isNull()) { 1473 if (!ReturnType->isRecordType()) 1474 return 0; 1475 // ... the same cv-unqualified type as the function return type ... 1476 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1477 return 0; 1478 } 1479 1480 // ... the expression is the name of a non-volatile automatic object 1481 // (other than a function or catch-clause parameter)) ... 1482 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1483 if (!DR) 1484 return 0; 1485 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1486 if (!VD) 1487 return 0; 1488 1489 if (VD->hasLocalStorage() && !VD->isExceptionVariable() && 1490 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1491 !VD->getType().isVolatileQualified() && 1492 ((VD->getKind() == Decl::Var) || 1493 (AllowFunctionParameter && VD->getKind() == Decl::ParmVar))) 1494 return VD; 1495 1496 return 0; 1497} 1498 1499/// \brief Perform the initialization of a potentially-movable value, which 1500/// is the result of return value. 1501/// 1502/// This routine implements C++0x [class.copy]p33, which attempts to treat 1503/// returned lvalues as rvalues in certain cases (to prefer move construction), 1504/// then falls back to treating them as lvalues if that failed. 1505ExprResult 1506Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1507 const VarDecl *NRVOCandidate, 1508 QualType ResultType, 1509 Expr *Value) { 1510 // C++0x [class.copy]p33: 1511 // When the criteria for elision of a copy operation are met or would 1512 // be met save for the fact that the source object is a function 1513 // parameter, and the object to be copied is designated by an lvalue, 1514 // overload resolution to select the constructor for the copy is first 1515 // performed as if the object were designated by an rvalue. 1516 ExprResult Res = ExprError(); 1517 if (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true)) { 1518 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1519 Value->getType(), CK_LValueToRValue, 1520 Value, VK_XValue); 1521 1522 Expr *InitExpr = &AsRvalue; 1523 InitializationKind Kind 1524 = InitializationKind::CreateCopy(Value->getLocStart(), 1525 Value->getLocStart()); 1526 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1527 1528 // [...] If overload resolution fails, or if the type of the first 1529 // parameter of the selected constructor is not an rvalue reference 1530 // to the object's type (possibly cv-qualified), overload resolution 1531 // is performed again, considering the object as an lvalue. 1532 if (Seq.getKind() != InitializationSequence::FailedSequence) { 1533 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1534 StepEnd = Seq.step_end(); 1535 Step != StepEnd; ++Step) { 1536 if (Step->Kind 1537 != InitializationSequence::SK_ConstructorInitialization) 1538 continue; 1539 1540 CXXConstructorDecl *Constructor 1541 = cast<CXXConstructorDecl>(Step->Function.Function); 1542 1543 const RValueReferenceType *RRefType 1544 = Constructor->getParamDecl(0)->getType() 1545 ->getAs<RValueReferenceType>(); 1546 1547 // If we don't meet the criteria, break out now. 1548 if (!RRefType || 1549 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1550 Context.getTypeDeclType(Constructor->getParent()))) 1551 break; 1552 1553 // Promote "AsRvalue" to the heap, since we now need this 1554 // expression node to persist. 1555 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1556 CK_LValueToRValue, Value, 0, 1557 VK_XValue); 1558 1559 // Complete type-checking the initialization of the return type 1560 // using the constructor we found. 1561 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1562 } 1563 } 1564 } 1565 1566 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1567 // above, or overload resolution failed. Either way, we need to try 1568 // (again) now with the return value expression as written. 1569 if (Res.isInvalid()) 1570 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1571 1572 return Res; 1573} 1574 1575/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1576/// 1577StmtResult 1578Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1579 // If this is the first return we've seen in the block, infer the type of 1580 // the block from it. 1581 BlockScopeInfo *CurBlock = getCurBlock(); 1582 if (CurBlock->ReturnType.isNull()) { 1583 if (RetValExp) { 1584 // Don't call UsualUnaryConversions(), since we don't want to do 1585 // integer promotions here. 1586 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 1587 if (Result.isInvalid()) 1588 return StmtError(); 1589 RetValExp = Result.take(); 1590 CurBlock->ReturnType = RetValExp->getType(); 1591 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1592 // We have to remove a 'const' added to copied-in variable which was 1593 // part of the implementation spec. and not the actual qualifier for 1594 // the variable. 1595 if (CDRE->isConstQualAdded()) 1596 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1597 } 1598 } else 1599 CurBlock->ReturnType = Context.VoidTy; 1600 } 1601 QualType FnRetType = CurBlock->ReturnType; 1602 1603 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1604 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1605 << getCurFunctionOrMethodDecl()->getDeclName(); 1606 return StmtError(); 1607 } 1608 1609 // Otherwise, verify that this result type matches the previous one. We are 1610 // pickier with blocks than for normal functions because we don't have GCC 1611 // compatibility to worry about here. 1612 ReturnStmt *Result = 0; 1613 if (CurBlock->ReturnType->isVoidType()) { 1614 if (RetValExp) { 1615 Diag(ReturnLoc, diag::err_return_block_has_expr); 1616 RetValExp = 0; 1617 } 1618 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1619 } else if (!RetValExp) { 1620 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1621 } else { 1622 const VarDecl *NRVOCandidate = 0; 1623 1624 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1625 // we have a non-void block with an expression, continue checking 1626 1627 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1628 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1629 // function return. 1630 1631 // In C++ the return statement is handled via a copy initialization. 1632 // the C version of which boils down to CheckSingleAssignmentConstraints. 1633 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1634 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1635 FnRetType, 1636 NRVOCandidate != 0); 1637 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1638 FnRetType, RetValExp); 1639 if (Res.isInvalid()) { 1640 // FIXME: Cleanup temporaries here, anyway? 1641 return StmtError(); 1642 } 1643 1644 if (RetValExp) { 1645 CheckImplicitConversions(RetValExp, ReturnLoc); 1646 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1647 } 1648 1649 RetValExp = Res.takeAs<Expr>(); 1650 if (RetValExp) 1651 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1652 } 1653 1654 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1655 } 1656 1657 // If we need to check for the named return value optimization, save the 1658 // return statement in our scope for later processing. 1659 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1660 !CurContext->isDependentContext()) 1661 FunctionScopes.back()->Returns.push_back(Result); 1662 1663 return Owned(Result); 1664} 1665 1666StmtResult 1667Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1668 if (getCurBlock()) 1669 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1670 1671 QualType FnRetType; 1672 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1673 FnRetType = FD->getResultType(); 1674 if (FD->hasAttr<NoReturnAttr>() || 1675 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1676 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1677 << getCurFunctionOrMethodDecl()->getDeclName(); 1678 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1679 FnRetType = MD->getResultType(); 1680 else // If we don't have a function/method context, bail. 1681 return StmtError(); 1682 1683 ReturnStmt *Result = 0; 1684 if (FnRetType->isVoidType()) { 1685 if (RetValExp && !RetValExp->isTypeDependent()) { 1686 // C99 6.8.6.4p1 (ext_ since GCC warns) 1687 unsigned D = diag::ext_return_has_expr; 1688 if (RetValExp->getType()->isVoidType()) 1689 D = diag::ext_return_has_void_expr; 1690 else { 1691 ExprResult Result = Owned(RetValExp); 1692 Result = IgnoredValueConversions(Result.take()); 1693 if (Result.isInvalid()) 1694 return StmtError(); 1695 RetValExp = Result.take(); 1696 RetValExp = ImpCastExprToType(RetValExp, Context.VoidTy, CK_ToVoid).take(); 1697 } 1698 1699 // return (some void expression); is legal in C++. 1700 if (D != diag::ext_return_has_void_expr || 1701 !getLangOptions().CPlusPlus) { 1702 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1703 Diag(ReturnLoc, D) 1704 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1705 << RetValExp->getSourceRange(); 1706 } 1707 1708 CheckImplicitConversions(RetValExp, ReturnLoc); 1709 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1710 } 1711 1712 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1713 } else if (!RetValExp && !FnRetType->isDependentType()) { 1714 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1715 // C99 6.8.6.4p1 (ext_ since GCC warns) 1716 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1717 1718 if (FunctionDecl *FD = getCurFunctionDecl()) 1719 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1720 else 1721 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1722 Result = new (Context) ReturnStmt(ReturnLoc); 1723 } else { 1724 const VarDecl *NRVOCandidate = 0; 1725 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1726 // we have a non-void function with an expression, continue checking 1727 1728 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1729 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1730 // function return. 1731 1732 // In C++ the return statement is handled via a copy initialization. 1733 // the C version of which boils down to CheckSingleAssignmentConstraints. 1734 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1735 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1736 FnRetType, 1737 NRVOCandidate != 0); 1738 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1739 FnRetType, RetValExp); 1740 if (Res.isInvalid()) { 1741 // FIXME: Cleanup temporaries here, anyway? 1742 return StmtError(); 1743 } 1744 1745 RetValExp = Res.takeAs<Expr>(); 1746 if (RetValExp) 1747 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1748 } 1749 1750 if (RetValExp) { 1751 CheckImplicitConversions(RetValExp, ReturnLoc); 1752 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1753 } 1754 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1755 } 1756 1757 // If we need to check for the named return value optimization, save the 1758 // return statement in our scope for later processing. 1759 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1760 !CurContext->isDependentContext()) 1761 FunctionScopes.back()->Returns.push_back(Result); 1762 1763 return Owned(Result); 1764} 1765 1766/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1767/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1768/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1769/// provide a strong guidance to not use it. 1770/// 1771/// This method checks to see if the argument is an acceptable l-value and 1772/// returns false if it is a case we can handle. 1773static bool CheckAsmLValue(const Expr *E, Sema &S) { 1774 // Type dependent expressions will be checked during instantiation. 1775 if (E->isTypeDependent()) 1776 return false; 1777 1778 if (E->isLValue()) 1779 return false; // Cool, this is an lvalue. 1780 1781 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1782 // are supposed to allow. 1783 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1784 if (E != E2 && E2->isLValue()) { 1785 if (!S.getLangOptions().HeinousExtensions) 1786 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1787 << E->getSourceRange(); 1788 else 1789 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1790 << E->getSourceRange(); 1791 // Accept, even if we emitted an error diagnostic. 1792 return false; 1793 } 1794 1795 // None of the above, just randomly invalid non-lvalue. 1796 return true; 1797} 1798 1799/// isOperandMentioned - Return true if the specified operand # is mentioned 1800/// anywhere in the decomposed asm string. 1801static bool isOperandMentioned(unsigned OpNo, 1802 llvm::ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 1803 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 1804 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 1805 if (!Piece.isOperand()) continue; 1806 1807 // If this is a reference to the input and if the input was the smaller 1808 // one, then we have to reject this asm. 1809 if (Piece.getOperandNo() == OpNo) 1810 return true; 1811 } 1812 1813 return false; 1814} 1815 1816StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 1817 bool IsVolatile, unsigned NumOutputs, 1818 unsigned NumInputs, IdentifierInfo **Names, 1819 MultiExprArg constraints, MultiExprArg exprs, 1820 Expr *asmString, MultiExprArg clobbers, 1821 SourceLocation RParenLoc, bool MSAsm) { 1822 unsigned NumClobbers = clobbers.size(); 1823 StringLiteral **Constraints = 1824 reinterpret_cast<StringLiteral**>(constraints.get()); 1825 Expr **Exprs = exprs.get(); 1826 StringLiteral *AsmString = cast<StringLiteral>(asmString); 1827 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1828 1829 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1830 1831 // The parser verifies that there is a string literal here. 1832 if (AsmString->isWide()) 1833 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1834 << AsmString->getSourceRange()); 1835 1836 for (unsigned i = 0; i != NumOutputs; i++) { 1837 StringLiteral *Literal = Constraints[i]; 1838 if (Literal->isWide()) 1839 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1840 << Literal->getSourceRange()); 1841 1842 llvm::StringRef OutputName; 1843 if (Names[i]) 1844 OutputName = Names[i]->getName(); 1845 1846 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1847 if (!Context.Target.validateOutputConstraint(Info)) 1848 return StmtError(Diag(Literal->getLocStart(), 1849 diag::err_asm_invalid_output_constraint) 1850 << Info.getConstraintStr()); 1851 1852 // Check that the output exprs are valid lvalues. 1853 Expr *OutputExpr = Exprs[i]; 1854 if (CheckAsmLValue(OutputExpr, *this)) { 1855 return StmtError(Diag(OutputExpr->getLocStart(), 1856 diag::err_asm_invalid_lvalue_in_output) 1857 << OutputExpr->getSourceRange()); 1858 } 1859 1860 OutputConstraintInfos.push_back(Info); 1861 } 1862 1863 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1864 1865 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1866 StringLiteral *Literal = Constraints[i]; 1867 if (Literal->isWide()) 1868 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1869 << Literal->getSourceRange()); 1870 1871 llvm::StringRef InputName; 1872 if (Names[i]) 1873 InputName = Names[i]->getName(); 1874 1875 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1876 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1877 NumOutputs, Info)) { 1878 return StmtError(Diag(Literal->getLocStart(), 1879 diag::err_asm_invalid_input_constraint) 1880 << Info.getConstraintStr()); 1881 } 1882 1883 Expr *InputExpr = Exprs[i]; 1884 1885 // Only allow void types for memory constraints. 1886 if (Info.allowsMemory() && !Info.allowsRegister()) { 1887 if (CheckAsmLValue(InputExpr, *this)) 1888 return StmtError(Diag(InputExpr->getLocStart(), 1889 diag::err_asm_invalid_lvalue_in_input) 1890 << Info.getConstraintStr() 1891 << InputExpr->getSourceRange()); 1892 } 1893 1894 if (Info.allowsRegister()) { 1895 if (InputExpr->getType()->isVoidType()) { 1896 return StmtError(Diag(InputExpr->getLocStart(), 1897 diag::err_asm_invalid_type_in_input) 1898 << InputExpr->getType() << Info.getConstraintStr() 1899 << InputExpr->getSourceRange()); 1900 } 1901 } 1902 1903 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 1904 if (Result.isInvalid()) 1905 return StmtError(); 1906 1907 Exprs[i] = Result.take(); 1908 InputConstraintInfos.push_back(Info); 1909 } 1910 1911 // Check that the clobbers are valid. 1912 for (unsigned i = 0; i != NumClobbers; i++) { 1913 StringLiteral *Literal = Clobbers[i]; 1914 if (Literal->isWide()) 1915 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1916 << Literal->getSourceRange()); 1917 1918 llvm::StringRef Clobber = Literal->getString(); 1919 1920 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1921 return StmtError(Diag(Literal->getLocStart(), 1922 diag::err_asm_unknown_register_name) << Clobber); 1923 } 1924 1925 AsmStmt *NS = 1926 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1927 NumOutputs, NumInputs, Names, Constraints, Exprs, 1928 AsmString, NumClobbers, Clobbers, RParenLoc); 1929 // Validate the asm string, ensuring it makes sense given the operands we 1930 // have. 1931 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1932 unsigned DiagOffs; 1933 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1934 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1935 << AsmString->getSourceRange(); 1936 return StmtError(); 1937 } 1938 1939 // Validate tied input operands for type mismatches. 1940 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1941 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1942 1943 // If this is a tied constraint, verify that the output and input have 1944 // either exactly the same type, or that they are int/ptr operands with the 1945 // same size (int/long, int*/long, are ok etc). 1946 if (!Info.hasTiedOperand()) continue; 1947 1948 unsigned TiedTo = Info.getTiedOperand(); 1949 unsigned InputOpNo = i+NumOutputs; 1950 Expr *OutputExpr = Exprs[TiedTo]; 1951 Expr *InputExpr = Exprs[InputOpNo]; 1952 QualType InTy = InputExpr->getType(); 1953 QualType OutTy = OutputExpr->getType(); 1954 if (Context.hasSameType(InTy, OutTy)) 1955 continue; // All types can be tied to themselves. 1956 1957 // Decide if the input and output are in the same domain (integer/ptr or 1958 // floating point. 1959 enum AsmDomain { 1960 AD_Int, AD_FP, AD_Other 1961 } InputDomain, OutputDomain; 1962 1963 if (InTy->isIntegerType() || InTy->isPointerType()) 1964 InputDomain = AD_Int; 1965 else if (InTy->isRealFloatingType()) 1966 InputDomain = AD_FP; 1967 else 1968 InputDomain = AD_Other; 1969 1970 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1971 OutputDomain = AD_Int; 1972 else if (OutTy->isRealFloatingType()) 1973 OutputDomain = AD_FP; 1974 else 1975 OutputDomain = AD_Other; 1976 1977 // They are ok if they are the same size and in the same domain. This 1978 // allows tying things like: 1979 // void* to int* 1980 // void* to int if they are the same size. 1981 // double to long double if they are the same size. 1982 // 1983 uint64_t OutSize = Context.getTypeSize(OutTy); 1984 uint64_t InSize = Context.getTypeSize(InTy); 1985 if (OutSize == InSize && InputDomain == OutputDomain && 1986 InputDomain != AD_Other) 1987 continue; 1988 1989 // If the smaller input/output operand is not mentioned in the asm string, 1990 // then we can promote the smaller one to a larger input and the asm string 1991 // won't notice. 1992 bool SmallerValueMentioned = false; 1993 1994 // If this is a reference to the input and if the input was the smaller 1995 // one, then we have to reject this asm. 1996 if (isOperandMentioned(InputOpNo, Pieces)) { 1997 // This is a use in the asm string of the smaller operand. Since we 1998 // codegen this by promoting to a wider value, the asm will get printed 1999 // "wrong". 2000 SmallerValueMentioned |= InSize < OutSize; 2001 } 2002 if (isOperandMentioned(TiedTo, Pieces)) { 2003 // If this is a reference to the output, and if the output is the larger 2004 // value, then it's ok because we'll promote the input to the larger type. 2005 SmallerValueMentioned |= OutSize < InSize; 2006 } 2007 2008 // If the smaller value wasn't mentioned in the asm string, and if the 2009 // output was a register, just extend the shorter one to the size of the 2010 // larger one. 2011 if (!SmallerValueMentioned && InputDomain != AD_Other && 2012 OutputConstraintInfos[TiedTo].allowsRegister()) 2013 continue; 2014 2015 // Either both of the operands were mentioned or the smaller one was 2016 // mentioned. One more special case that we'll allow: if the tied input is 2017 // integer, unmentioned, and is a constant, then we'll allow truncating it 2018 // down to the size of the destination. 2019 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2020 !isOperandMentioned(InputOpNo, Pieces) && 2021 InputExpr->isEvaluatable(Context)) { 2022 CastKind castKind = 2023 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2024 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2025 Exprs[InputOpNo] = InputExpr; 2026 NS->setInputExpr(i, InputExpr); 2027 continue; 2028 } 2029 2030 Diag(InputExpr->getLocStart(), 2031 diag::err_asm_tying_incompatible_types) 2032 << InTy << OutTy << OutputExpr->getSourceRange() 2033 << InputExpr->getSourceRange(); 2034 return StmtError(); 2035 } 2036 2037 return Owned(NS); 2038} 2039 2040StmtResult 2041Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2042 SourceLocation RParen, Decl *Parm, 2043 Stmt *Body) { 2044 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2045 if (Var && Var->isInvalidDecl()) 2046 return StmtError(); 2047 2048 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2049} 2050 2051StmtResult 2052Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2053 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2054} 2055 2056StmtResult 2057Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2058 MultiStmtArg CatchStmts, Stmt *Finally) { 2059 if (!getLangOptions().ObjCExceptions) 2060 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2061 2062 getCurFunction()->setHasBranchProtectedScope(); 2063 unsigned NumCatchStmts = CatchStmts.size(); 2064 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2065 CatchStmts.release(), 2066 NumCatchStmts, 2067 Finally)); 2068} 2069 2070StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 2071 Expr *Throw) { 2072 if (Throw) { 2073 ExprResult Result = DefaultLvalueConversion(Throw); 2074 if (Result.isInvalid()) 2075 return StmtError(); 2076 2077 Throw = Result.take(); 2078 QualType ThrowType = Throw->getType(); 2079 // Make sure the expression type is an ObjC pointer or "void *". 2080 if (!ThrowType->isDependentType() && 2081 !ThrowType->isObjCObjectPointerType()) { 2082 const PointerType *PT = ThrowType->getAs<PointerType>(); 2083 if (!PT || !PT->getPointeeType()->isVoidType()) 2084 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2085 << Throw->getType() << Throw->getSourceRange()); 2086 } 2087 } 2088 2089 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2090} 2091 2092StmtResult 2093Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2094 Scope *CurScope) { 2095 if (!getLangOptions().ObjCExceptions) 2096 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2097 2098 if (!Throw) { 2099 // @throw without an expression designates a rethrow (which much occur 2100 // in the context of an @catch clause). 2101 Scope *AtCatchParent = CurScope; 2102 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2103 AtCatchParent = AtCatchParent->getParent(); 2104 if (!AtCatchParent) 2105 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2106 } 2107 2108 return BuildObjCAtThrowStmt(AtLoc, Throw); 2109} 2110 2111StmtResult 2112Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2113 Stmt *SyncBody) { 2114 getCurFunction()->setHasBranchProtectedScope(); 2115 2116 ExprResult Result = DefaultLvalueConversion(SyncExpr); 2117 if (Result.isInvalid()) 2118 return StmtError(); 2119 2120 SyncExpr = Result.take(); 2121 // Make sure the expression type is an ObjC pointer or "void *". 2122 if (!SyncExpr->getType()->isDependentType() && 2123 !SyncExpr->getType()->isObjCObjectPointerType()) { 2124 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 2125 if (!PT || !PT->getPointeeType()->isVoidType()) 2126 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 2127 << SyncExpr->getType() << SyncExpr->getSourceRange()); 2128 } 2129 2130 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2131} 2132 2133/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2134/// and creates a proper catch handler from them. 2135StmtResult 2136Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2137 Stmt *HandlerBlock) { 2138 // There's nothing to test that ActOnExceptionDecl didn't already test. 2139 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2140 cast_or_null<VarDecl>(ExDecl), 2141 HandlerBlock)); 2142} 2143 2144namespace { 2145 2146class TypeWithHandler { 2147 QualType t; 2148 CXXCatchStmt *stmt; 2149public: 2150 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2151 : t(type), stmt(statement) {} 2152 2153 // An arbitrary order is fine as long as it places identical 2154 // types next to each other. 2155 bool operator<(const TypeWithHandler &y) const { 2156 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2157 return true; 2158 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2159 return false; 2160 else 2161 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2162 } 2163 2164 bool operator==(const TypeWithHandler& other) const { 2165 return t == other.t; 2166 } 2167 2168 CXXCatchStmt *getCatchStmt() const { return stmt; } 2169 SourceLocation getTypeSpecStartLoc() const { 2170 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2171 } 2172}; 2173 2174} 2175 2176/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2177/// handlers and creates a try statement from them. 2178StmtResult 2179Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2180 MultiStmtArg RawHandlers) { 2181 // Don't report an error if 'try' is used in system headers. 2182 if (!getLangOptions().CXXExceptions && 2183 !getSourceManager().isInSystemHeader(TryLoc)) 2184 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2185 2186 unsigned NumHandlers = RawHandlers.size(); 2187 assert(NumHandlers > 0 && 2188 "The parser shouldn't call this if there are no handlers."); 2189 Stmt **Handlers = RawHandlers.get(); 2190 2191 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2192 2193 for (unsigned i = 0; i < NumHandlers; ++i) { 2194 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 2195 if (!Handler->getExceptionDecl()) { 2196 if (i < NumHandlers - 1) 2197 return StmtError(Diag(Handler->getLocStart(), 2198 diag::err_early_catch_all)); 2199 2200 continue; 2201 } 2202 2203 const QualType CaughtType = Handler->getCaughtType(); 2204 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2205 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2206 } 2207 2208 // Detect handlers for the same type as an earlier one. 2209 if (NumHandlers > 1) { 2210 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2211 2212 TypeWithHandler prev = TypesWithHandlers[0]; 2213 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2214 TypeWithHandler curr = TypesWithHandlers[i]; 2215 2216 if (curr == prev) { 2217 Diag(curr.getTypeSpecStartLoc(), 2218 diag::warn_exception_caught_by_earlier_handler) 2219 << curr.getCatchStmt()->getCaughtType().getAsString(); 2220 Diag(prev.getTypeSpecStartLoc(), 2221 diag::note_previous_exception_handler) 2222 << prev.getCatchStmt()->getCaughtType().getAsString(); 2223 } 2224 2225 prev = curr; 2226 } 2227 } 2228 2229 getCurFunction()->setHasBranchProtectedScope(); 2230 2231 // FIXME: We should detect handlers that cannot catch anything because an 2232 // earlier handler catches a superclass. Need to find a method that is not 2233 // quadratic for this. 2234 // Neither of these are explicitly forbidden, but every compiler detects them 2235 // and warns. 2236 2237 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2238 Handlers, NumHandlers)); 2239} 2240 2241StmtResult 2242Sema::ActOnSEHTryBlock(bool IsCXXTry, 2243 SourceLocation TryLoc, 2244 Stmt *TryBlock, 2245 Stmt *Handler) { 2246 assert(TryBlock && Handler); 2247 2248 getCurFunction()->setHasBranchProtectedScope(); 2249 2250 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2251} 2252 2253StmtResult 2254Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2255 Expr *FilterExpr, 2256 Stmt *Block) { 2257 assert(FilterExpr && Block); 2258 2259 if(!FilterExpr->getType()->isIntegerType()) { 2260 return StmtError(Diag(FilterExpr->getExprLoc(), diag::err_filter_expression_integral) << FilterExpr->getType()); 2261 } 2262 2263 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2264} 2265 2266StmtResult 2267Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2268 Stmt *Block) { 2269 assert(Block); 2270 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2271} 2272 2273