SemaStmt.cpp revision 3940ce83438e2332ba541f4e65e700fbefe0c7a8
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/ASTContext.h" 20#include "clang/AST/CharUnits.h" 21#include "clang/AST/DeclObjC.h" 22#include "clang/AST/EvaluatedExprVisitor.h" 23#include "clang/AST/ExprCXX.h" 24#include "clang/AST/ExprObjC.h" 25#include "clang/AST/StmtObjC.h" 26#include "clang/AST/StmtCXX.h" 27#include "clang/AST/TypeLoc.h" 28#include "clang/Lex/Preprocessor.h" 29#include "clang/Basic/TargetInfo.h" 30#include "llvm/ADT/ArrayRef.h" 31#include "llvm/ADT/STLExtras.h" 32#include "llvm/ADT/SmallPtrSet.h" 33#include "llvm/ADT/SmallVector.h" 34using namespace clang; 35using namespace sema; 36 37StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 38 Expr *E = expr.get(); 39 if (!E) // FIXME: FullExprArg has no error state? 40 return StmtError(); 41 42 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 43 // void expression for its side effects. Conversion to void allows any 44 // operand, even incomplete types. 45 46 // Same thing in for stmt first clause (when expr) and third clause. 47 return Owned(static_cast<Stmt*>(E)); 48} 49 50 51StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, 52 bool HasLeadingEmptyMacro) { 53 return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro)); 54} 55 56StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 57 SourceLocation EndLoc) { 58 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 59 60 // If we have an invalid decl, just return an error. 61 if (DG.isNull()) return StmtError(); 62 63 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 64} 65 66void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 67 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 68 69 // If we have an invalid decl, just return. 70 if (DG.isNull() || !DG.isSingleDecl()) return; 71 VarDecl *var = cast<VarDecl>(DG.getSingleDecl()); 72 73 // suppress any potential 'unused variable' warning. 74 var->setUsed(); 75 76 // foreach variables are never actually initialized in the way that 77 // the parser came up with. 78 var->setInit(0); 79 80 // In ARC, we don't need to retain the iteration variable of a fast 81 // enumeration loop. Rather than actually trying to catch that 82 // during declaration processing, we remove the consequences here. 83 if (getLangOpts().ObjCAutoRefCount) { 84 QualType type = var->getType(); 85 86 // Only do this if we inferred the lifetime. Inferred lifetime 87 // will show up as a local qualifier because explicit lifetime 88 // should have shown up as an AttributedType instead. 89 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { 90 // Add 'const' and mark the variable as pseudo-strong. 91 var->setType(type.withConst()); 92 var->setARCPseudoStrong(true); 93 } 94 } 95} 96 97/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='. 98/// 99/// Adding a cast to void (or other expression wrappers) will prevent the 100/// warning from firing. 101static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) { 102 SourceLocation Loc; 103 bool IsNotEqual, CanAssign; 104 105 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) { 106 if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE) 107 return false; 108 109 Loc = Op->getOperatorLoc(); 110 IsNotEqual = Op->getOpcode() == BO_NE; 111 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue(); 112 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) { 113 if (Op->getOperator() != OO_EqualEqual && 114 Op->getOperator() != OO_ExclaimEqual) 115 return false; 116 117 Loc = Op->getOperatorLoc(); 118 IsNotEqual = Op->getOperator() == OO_ExclaimEqual; 119 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue(); 120 } else { 121 // Not a typo-prone comparison. 122 return false; 123 } 124 125 // Suppress warnings when the operator, suspicious as it may be, comes from 126 // a macro expansion. 127 if (Loc.isMacroID()) 128 return false; 129 130 S.Diag(Loc, diag::warn_unused_comparison) 131 << (unsigned)IsNotEqual << E->getSourceRange(); 132 133 // If the LHS is a plausible entity to assign to, provide a fixit hint to 134 // correct common typos. 135 if (CanAssign) { 136 if (IsNotEqual) 137 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign) 138 << FixItHint::CreateReplacement(Loc, "|="); 139 else 140 S.Diag(Loc, diag::note_equality_comparison_to_assign) 141 << FixItHint::CreateReplacement(Loc, "="); 142 } 143 144 return true; 145} 146 147void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 148 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 149 return DiagnoseUnusedExprResult(Label->getSubStmt()); 150 151 const Expr *E = dyn_cast_or_null<Expr>(S); 152 if (!E) 153 return; 154 155 SourceLocation Loc; 156 SourceRange R1, R2; 157 if (SourceMgr.isInSystemMacro(E->getExprLoc()) || 158 !E->isUnusedResultAWarning(Loc, R1, R2, Context)) 159 return; 160 161 // Okay, we have an unused result. Depending on what the base expression is, 162 // we might want to make a more specific diagnostic. Check for one of these 163 // cases now. 164 unsigned DiagID = diag::warn_unused_expr; 165 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 166 E = Temps->getSubExpr(); 167 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 168 E = TempExpr->getSubExpr(); 169 170 if (DiagnoseUnusedComparison(*this, E)) 171 return; 172 173 E = E->IgnoreParenImpCasts(); 174 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 175 if (E->getType()->isVoidType()) 176 return; 177 178 // If the callee has attribute pure, const, or warn_unused_result, warn with 179 // a more specific message to make it clear what is happening. 180 if (const Decl *FD = CE->getCalleeDecl()) { 181 if (FD->getAttr<WarnUnusedResultAttr>()) { 182 Diag(Loc, diag::warn_unused_result) << R1 << R2; 183 return; 184 } 185 if (FD->getAttr<PureAttr>()) { 186 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 187 return; 188 } 189 if (FD->getAttr<ConstAttr>()) { 190 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 191 return; 192 } 193 } 194 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 195 if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) { 196 Diag(Loc, diag::err_arc_unused_init_message) << R1; 197 return; 198 } 199 const ObjCMethodDecl *MD = ME->getMethodDecl(); 200 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 201 Diag(Loc, diag::warn_unused_result) << R1 << R2; 202 return; 203 } 204 } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) { 205 const Expr *Source = POE->getSyntacticForm(); 206 if (isa<ObjCSubscriptRefExpr>(Source)) 207 DiagID = diag::warn_unused_container_subscript_expr; 208 else 209 DiagID = diag::warn_unused_property_expr; 210 } else if (const CXXFunctionalCastExpr *FC 211 = dyn_cast<CXXFunctionalCastExpr>(E)) { 212 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 213 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 214 return; 215 } 216 // Diagnose "(void*) blah" as a typo for "(void) blah". 217 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 218 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 219 QualType T = TI->getType(); 220 221 // We really do want to use the non-canonical type here. 222 if (T == Context.VoidPtrTy) { 223 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 224 225 Diag(Loc, diag::warn_unused_voidptr) 226 << FixItHint::CreateRemoval(TL.getStarLoc()); 227 return; 228 } 229 } 230 231 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 232} 233 234void Sema::ActOnStartOfCompoundStmt() { 235 PushCompoundScope(); 236} 237 238void Sema::ActOnFinishOfCompoundStmt() { 239 PopCompoundScope(); 240} 241 242sema::CompoundScopeInfo &Sema::getCurCompoundScope() const { 243 return getCurFunction()->CompoundScopes.back(); 244} 245 246StmtResult 247Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 248 MultiStmtArg elts, bool isStmtExpr) { 249 unsigned NumElts = elts.size(); 250 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 251 // If we're in C89 mode, check that we don't have any decls after stmts. If 252 // so, emit an extension diagnostic. 253 if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) { 254 // Note that __extension__ can be around a decl. 255 unsigned i = 0; 256 // Skip over all declarations. 257 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 258 /*empty*/; 259 260 // We found the end of the list or a statement. Scan for another declstmt. 261 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 262 /*empty*/; 263 264 if (i != NumElts) { 265 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 266 Diag(D->getLocation(), diag::ext_mixed_decls_code); 267 } 268 } 269 // Warn about unused expressions in statements. 270 for (unsigned i = 0; i != NumElts; ++i) { 271 // Ignore statements that are last in a statement expression. 272 if (isStmtExpr && i == NumElts - 1) 273 continue; 274 275 DiagnoseUnusedExprResult(Elts[i]); 276 } 277 278 // Check for suspicious empty body (null statement) in `for' and `while' 279 // statements. Don't do anything for template instantiations, this just adds 280 // noise. 281 if (NumElts != 0 && !CurrentInstantiationScope && 282 getCurCompoundScope().HasEmptyLoopBodies) { 283 for (unsigned i = 0; i != NumElts - 1; ++i) 284 DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]); 285 } 286 287 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 288} 289 290StmtResult 291Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 292 SourceLocation DotDotDotLoc, Expr *RHSVal, 293 SourceLocation ColonLoc) { 294 assert((LHSVal != 0) && "missing expression in case statement"); 295 296 if (getCurFunction()->SwitchStack.empty()) { 297 Diag(CaseLoc, diag::err_case_not_in_switch); 298 return StmtError(); 299 } 300 301 if (!getLangOpts().CPlusPlus0x) { 302 // C99 6.8.4.2p3: The expression shall be an integer constant. 303 // However, GCC allows any evaluatable integer expression. 304 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) { 305 LHSVal = VerifyIntegerConstantExpression(LHSVal).take(); 306 if (!LHSVal) 307 return StmtError(); 308 } 309 310 // GCC extension: The expression shall be an integer constant. 311 312 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) { 313 RHSVal = VerifyIntegerConstantExpression(RHSVal).take(); 314 // Recover from an error by just forgetting about it. 315 } 316 } 317 318 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 319 ColonLoc); 320 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 321 return Owned(CS); 322} 323 324/// ActOnCaseStmtBody - This installs a statement as the body of a case. 325void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 326 DiagnoseUnusedExprResult(SubStmt); 327 328 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 329 CS->setSubStmt(SubStmt); 330} 331 332StmtResult 333Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 334 Stmt *SubStmt, Scope *CurScope) { 335 DiagnoseUnusedExprResult(SubStmt); 336 337 if (getCurFunction()->SwitchStack.empty()) { 338 Diag(DefaultLoc, diag::err_default_not_in_switch); 339 return Owned(SubStmt); 340 } 341 342 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 343 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 344 return Owned(DS); 345} 346 347StmtResult 348Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 349 SourceLocation ColonLoc, Stmt *SubStmt) { 350 // If the label was multiply defined, reject it now. 351 if (TheDecl->getStmt()) { 352 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 353 Diag(TheDecl->getLocation(), diag::note_previous_definition); 354 return Owned(SubStmt); 355 } 356 357 // Otherwise, things are good. Fill in the declaration and return it. 358 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 359 TheDecl->setStmt(LS); 360 if (!TheDecl->isGnuLocal()) 361 TheDecl->setLocation(IdentLoc); 362 return Owned(LS); 363} 364 365StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc, 366 const AttrVec &Attrs, 367 Stmt *SubStmt) { 368 // Fill in the declaration and return it. Variable length will require to 369 // change this to AttributedStmt::Create(Context, ....); 370 // and probably using ArrayRef 371 AttributedStmt *LS = new (Context) AttributedStmt(AttrLoc, Attrs, SubStmt); 372 return Owned(LS); 373} 374 375StmtResult 376Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 377 Stmt *thenStmt, SourceLocation ElseLoc, 378 Stmt *elseStmt) { 379 ExprResult CondResult(CondVal.release()); 380 381 VarDecl *ConditionVar = 0; 382 if (CondVar) { 383 ConditionVar = cast<VarDecl>(CondVar); 384 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 385 if (CondResult.isInvalid()) 386 return StmtError(); 387 } 388 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 389 if (!ConditionExpr) 390 return StmtError(); 391 392 DiagnoseUnusedExprResult(thenStmt); 393 394 if (!elseStmt) { 395 DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt, 396 diag::warn_empty_if_body); 397 } 398 399 DiagnoseUnusedExprResult(elseStmt); 400 401 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 402 thenStmt, ElseLoc, elseStmt)); 403} 404 405/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 406/// the specified width and sign. If an overflow occurs, detect it and emit 407/// the specified diagnostic. 408void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 409 unsigned NewWidth, bool NewSign, 410 SourceLocation Loc, 411 unsigned DiagID) { 412 // Perform a conversion to the promoted condition type if needed. 413 if (NewWidth > Val.getBitWidth()) { 414 // If this is an extension, just do it. 415 Val = Val.extend(NewWidth); 416 Val.setIsSigned(NewSign); 417 418 // If the input was signed and negative and the output is 419 // unsigned, don't bother to warn: this is implementation-defined 420 // behavior. 421 // FIXME: Introduce a second, default-ignored warning for this case? 422 } else if (NewWidth < Val.getBitWidth()) { 423 // If this is a truncation, check for overflow. 424 llvm::APSInt ConvVal(Val); 425 ConvVal = ConvVal.trunc(NewWidth); 426 ConvVal.setIsSigned(NewSign); 427 ConvVal = ConvVal.extend(Val.getBitWidth()); 428 ConvVal.setIsSigned(Val.isSigned()); 429 if (ConvVal != Val) 430 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 431 432 // Regardless of whether a diagnostic was emitted, really do the 433 // truncation. 434 Val = Val.trunc(NewWidth); 435 Val.setIsSigned(NewSign); 436 } else if (NewSign != Val.isSigned()) { 437 // Convert the sign to match the sign of the condition. This can cause 438 // overflow as well: unsigned(INTMIN) 439 // We don't diagnose this overflow, because it is implementation-defined 440 // behavior. 441 // FIXME: Introduce a second, default-ignored warning for this case? 442 llvm::APSInt OldVal(Val); 443 Val.setIsSigned(NewSign); 444 } 445} 446 447namespace { 448 struct CaseCompareFunctor { 449 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 450 const llvm::APSInt &RHS) { 451 return LHS.first < RHS; 452 } 453 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 454 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 455 return LHS.first < RHS.first; 456 } 457 bool operator()(const llvm::APSInt &LHS, 458 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 459 return LHS < RHS.first; 460 } 461 }; 462} 463 464/// CmpCaseVals - Comparison predicate for sorting case values. 465/// 466static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 467 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 468 if (lhs.first < rhs.first) 469 return true; 470 471 if (lhs.first == rhs.first && 472 lhs.second->getCaseLoc().getRawEncoding() 473 < rhs.second->getCaseLoc().getRawEncoding()) 474 return true; 475 return false; 476} 477 478/// CmpEnumVals - Comparison predicate for sorting enumeration values. 479/// 480static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 481 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 482{ 483 return lhs.first < rhs.first; 484} 485 486/// EqEnumVals - Comparison preficate for uniqing enumeration values. 487/// 488static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 489 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 490{ 491 return lhs.first == rhs.first; 492} 493 494/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 495/// potentially integral-promoted expression @p expr. 496static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 497 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 498 expr = cleanups->getSubExpr(); 499 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 500 if (impcast->getCastKind() != CK_IntegralCast) break; 501 expr = impcast->getSubExpr(); 502 } 503 return expr->getType(); 504} 505 506StmtResult 507Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 508 Decl *CondVar) { 509 ExprResult CondResult; 510 511 VarDecl *ConditionVar = 0; 512 if (CondVar) { 513 ConditionVar = cast<VarDecl>(CondVar); 514 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 515 if (CondResult.isInvalid()) 516 return StmtError(); 517 518 Cond = CondResult.release(); 519 } 520 521 if (!Cond) 522 return StmtError(); 523 524 class SwitchConvertDiagnoser : public ICEConvertDiagnoser { 525 Expr *Cond; 526 527 public: 528 SwitchConvertDiagnoser(Expr *Cond) 529 : ICEConvertDiagnoser(false, true), Cond(Cond) { } 530 531 virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc, 532 QualType T) { 533 return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T; 534 } 535 536 virtual DiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc, 537 QualType T) { 538 return S.Diag(Loc, diag::err_switch_incomplete_class_type) 539 << T << Cond->getSourceRange(); 540 } 541 542 virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc, 543 QualType T, 544 QualType ConvTy) { 545 return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy; 546 } 547 548 virtual DiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv, 549 QualType ConvTy) { 550 return S.Diag(Conv->getLocation(), diag::note_switch_conversion) 551 << ConvTy->isEnumeralType() << ConvTy; 552 } 553 554 virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc, 555 QualType T) { 556 return S.Diag(Loc, diag::err_switch_multiple_conversions) << T; 557 } 558 559 virtual DiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv, 560 QualType ConvTy) { 561 return S.Diag(Conv->getLocation(), diag::note_switch_conversion) 562 << ConvTy->isEnumeralType() << ConvTy; 563 } 564 565 virtual DiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc, 566 QualType T, 567 QualType ConvTy) { 568 return DiagnosticBuilder::getEmpty(); 569 } 570 } SwitchDiagnoser(Cond); 571 572 CondResult 573 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, SwitchDiagnoser, 574 /*AllowScopedEnumerations*/ true); 575 if (CondResult.isInvalid()) return StmtError(); 576 Cond = CondResult.take(); 577 578 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 579 CondResult = UsualUnaryConversions(Cond); 580 if (CondResult.isInvalid()) return StmtError(); 581 Cond = CondResult.take(); 582 583 if (!CondVar) { 584 CheckImplicitConversions(Cond, SwitchLoc); 585 CondResult = MaybeCreateExprWithCleanups(Cond); 586 if (CondResult.isInvalid()) 587 return StmtError(); 588 Cond = CondResult.take(); 589 } 590 591 getCurFunction()->setHasBranchIntoScope(); 592 593 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 594 getCurFunction()->SwitchStack.push_back(SS); 595 return Owned(SS); 596} 597 598static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 599 if (Val.getBitWidth() < BitWidth) 600 Val = Val.extend(BitWidth); 601 else if (Val.getBitWidth() > BitWidth) 602 Val = Val.trunc(BitWidth); 603 Val.setIsSigned(IsSigned); 604} 605 606StmtResult 607Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 608 Stmt *BodyStmt) { 609 SwitchStmt *SS = cast<SwitchStmt>(Switch); 610 assert(SS == getCurFunction()->SwitchStack.back() && 611 "switch stack missing push/pop!"); 612 613 SS->setBody(BodyStmt, SwitchLoc); 614 getCurFunction()->SwitchStack.pop_back(); 615 616 Expr *CondExpr = SS->getCond(); 617 if (!CondExpr) return StmtError(); 618 619 QualType CondType = CondExpr->getType(); 620 621 Expr *CondExprBeforePromotion = CondExpr; 622 QualType CondTypeBeforePromotion = 623 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 624 625 // C++ 6.4.2.p2: 626 // Integral promotions are performed (on the switch condition). 627 // 628 // A case value unrepresentable by the original switch condition 629 // type (before the promotion) doesn't make sense, even when it can 630 // be represented by the promoted type. Therefore we need to find 631 // the pre-promotion type of the switch condition. 632 if (!CondExpr->isTypeDependent()) { 633 // We have already converted the expression to an integral or enumeration 634 // type, when we started the switch statement. If we don't have an 635 // appropriate type now, just return an error. 636 if (!CondType->isIntegralOrEnumerationType()) 637 return StmtError(); 638 639 if (CondExpr->isKnownToHaveBooleanValue()) { 640 // switch(bool_expr) {...} is often a programmer error, e.g. 641 // switch(n && mask) { ... } // Doh - should be "n & mask". 642 // One can always use an if statement instead of switch(bool_expr). 643 Diag(SwitchLoc, diag::warn_bool_switch_condition) 644 << CondExpr->getSourceRange(); 645 } 646 } 647 648 // Get the bitwidth of the switched-on value before promotions. We must 649 // convert the integer case values to this width before comparison. 650 bool HasDependentValue 651 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 652 unsigned CondWidth 653 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 654 bool CondIsSigned 655 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 656 657 // Accumulate all of the case values in a vector so that we can sort them 658 // and detect duplicates. This vector contains the APInt for the case after 659 // it has been converted to the condition type. 660 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 661 CaseValsTy CaseVals; 662 663 // Keep track of any GNU case ranges we see. The APSInt is the low value. 664 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 665 CaseRangesTy CaseRanges; 666 667 DefaultStmt *TheDefaultStmt = 0; 668 669 bool CaseListIsErroneous = false; 670 671 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 672 SC = SC->getNextSwitchCase()) { 673 674 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 675 if (TheDefaultStmt) { 676 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 677 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 678 679 // FIXME: Remove the default statement from the switch block so that 680 // we'll return a valid AST. This requires recursing down the AST and 681 // finding it, not something we are set up to do right now. For now, 682 // just lop the entire switch stmt out of the AST. 683 CaseListIsErroneous = true; 684 } 685 TheDefaultStmt = DS; 686 687 } else { 688 CaseStmt *CS = cast<CaseStmt>(SC); 689 690 Expr *Lo = CS->getLHS(); 691 692 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 693 HasDependentValue = true; 694 break; 695 } 696 697 llvm::APSInt LoVal; 698 699 if (getLangOpts().CPlusPlus0x) { 700 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 701 // constant expression of the promoted type of the switch condition. 702 ExprResult ConvLo = 703 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue); 704 if (ConvLo.isInvalid()) { 705 CaseListIsErroneous = true; 706 continue; 707 } 708 Lo = ConvLo.take(); 709 } else { 710 // We already verified that the expression has a i-c-e value (C99 711 // 6.8.4.2p3) - get that value now. 712 LoVal = Lo->EvaluateKnownConstInt(Context); 713 714 // If the LHS is not the same type as the condition, insert an implicit 715 // cast. 716 Lo = DefaultLvalueConversion(Lo).take(); 717 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 718 } 719 720 // Convert the value to the same width/sign as the condition had prior to 721 // integral promotions. 722 // 723 // FIXME: This causes us to reject valid code: 724 // switch ((char)c) { case 256: case 0: return 0; } 725 // Here we claim there is a duplicated condition value, but there is not. 726 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 727 Lo->getLocStart(), 728 diag::warn_case_value_overflow); 729 730 CS->setLHS(Lo); 731 732 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 733 if (CS->getRHS()) { 734 if (CS->getRHS()->isTypeDependent() || 735 CS->getRHS()->isValueDependent()) { 736 HasDependentValue = true; 737 break; 738 } 739 CaseRanges.push_back(std::make_pair(LoVal, CS)); 740 } else 741 CaseVals.push_back(std::make_pair(LoVal, CS)); 742 } 743 } 744 745 if (!HasDependentValue) { 746 // If we don't have a default statement, check whether the 747 // condition is constant. 748 llvm::APSInt ConstantCondValue; 749 bool HasConstantCond = false; 750 if (!HasDependentValue && !TheDefaultStmt) { 751 HasConstantCond 752 = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context, 753 Expr::SE_AllowSideEffects); 754 assert(!HasConstantCond || 755 (ConstantCondValue.getBitWidth() == CondWidth && 756 ConstantCondValue.isSigned() == CondIsSigned)); 757 } 758 bool ShouldCheckConstantCond = HasConstantCond; 759 760 // Sort all the scalar case values so we can easily detect duplicates. 761 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 762 763 if (!CaseVals.empty()) { 764 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 765 if (ShouldCheckConstantCond && 766 CaseVals[i].first == ConstantCondValue) 767 ShouldCheckConstantCond = false; 768 769 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 770 // If we have a duplicate, report it. 771 // First, determine if either case value has a name 772 StringRef PrevString, CurrString; 773 Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts(); 774 Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts(); 775 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) { 776 PrevString = DeclRef->getDecl()->getName(); 777 } 778 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) { 779 CurrString = DeclRef->getDecl()->getName(); 780 } 781 std::string CaseValStr = CaseVals[i-1].first.toString(10); 782 783 if (PrevString == CurrString) 784 Diag(CaseVals[i].second->getLHS()->getLocStart(), 785 diag::err_duplicate_case) << 786 (PrevString.empty() ? CaseValStr : PrevString.str()); 787 else 788 Diag(CaseVals[i].second->getLHS()->getLocStart(), 789 diag::err_duplicate_case_differing_expr) << 790 (PrevString.empty() ? CaseValStr : PrevString.str()) << 791 (CurrString.empty() ? CaseValStr : CurrString.str()) << 792 CaseValStr; 793 794 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 795 diag::note_duplicate_case_prev); 796 // FIXME: We really want to remove the bogus case stmt from the 797 // substmt, but we have no way to do this right now. 798 CaseListIsErroneous = true; 799 } 800 } 801 } 802 803 // Detect duplicate case ranges, which usually don't exist at all in 804 // the first place. 805 if (!CaseRanges.empty()) { 806 // Sort all the case ranges by their low value so we can easily detect 807 // overlaps between ranges. 808 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 809 810 // Scan the ranges, computing the high values and removing empty ranges. 811 std::vector<llvm::APSInt> HiVals; 812 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 813 llvm::APSInt &LoVal = CaseRanges[i].first; 814 CaseStmt *CR = CaseRanges[i].second; 815 Expr *Hi = CR->getRHS(); 816 llvm::APSInt HiVal; 817 818 if (getLangOpts().CPlusPlus0x) { 819 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 820 // constant expression of the promoted type of the switch condition. 821 ExprResult ConvHi = 822 CheckConvertedConstantExpression(Hi, CondType, HiVal, 823 CCEK_CaseValue); 824 if (ConvHi.isInvalid()) { 825 CaseListIsErroneous = true; 826 continue; 827 } 828 Hi = ConvHi.take(); 829 } else { 830 HiVal = Hi->EvaluateKnownConstInt(Context); 831 832 // If the RHS is not the same type as the condition, insert an 833 // implicit cast. 834 Hi = DefaultLvalueConversion(Hi).take(); 835 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 836 } 837 838 // Convert the value to the same width/sign as the condition. 839 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 840 Hi->getLocStart(), 841 diag::warn_case_value_overflow); 842 843 CR->setRHS(Hi); 844 845 // If the low value is bigger than the high value, the case is empty. 846 if (LoVal > HiVal) { 847 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 848 << SourceRange(CR->getLHS()->getLocStart(), 849 Hi->getLocEnd()); 850 CaseRanges.erase(CaseRanges.begin()+i); 851 --i, --e; 852 continue; 853 } 854 855 if (ShouldCheckConstantCond && 856 LoVal <= ConstantCondValue && 857 ConstantCondValue <= HiVal) 858 ShouldCheckConstantCond = false; 859 860 HiVals.push_back(HiVal); 861 } 862 863 // Rescan the ranges, looking for overlap with singleton values and other 864 // ranges. Since the range list is sorted, we only need to compare case 865 // ranges with their neighbors. 866 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 867 llvm::APSInt &CRLo = CaseRanges[i].first; 868 llvm::APSInt &CRHi = HiVals[i]; 869 CaseStmt *CR = CaseRanges[i].second; 870 871 // Check to see whether the case range overlaps with any 872 // singleton cases. 873 CaseStmt *OverlapStmt = 0; 874 llvm::APSInt OverlapVal(32); 875 876 // Find the smallest value >= the lower bound. If I is in the 877 // case range, then we have overlap. 878 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 879 CaseVals.end(), CRLo, 880 CaseCompareFunctor()); 881 if (I != CaseVals.end() && I->first < CRHi) { 882 OverlapVal = I->first; // Found overlap with scalar. 883 OverlapStmt = I->second; 884 } 885 886 // Find the smallest value bigger than the upper bound. 887 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 888 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 889 OverlapVal = (I-1)->first; // Found overlap with scalar. 890 OverlapStmt = (I-1)->second; 891 } 892 893 // Check to see if this case stmt overlaps with the subsequent 894 // case range. 895 if (i && CRLo <= HiVals[i-1]) { 896 OverlapVal = HiVals[i-1]; // Found overlap with range. 897 OverlapStmt = CaseRanges[i-1].second; 898 } 899 900 if (OverlapStmt) { 901 // If we have a duplicate, report it. 902 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 903 << OverlapVal.toString(10); 904 Diag(OverlapStmt->getLHS()->getLocStart(), 905 diag::note_duplicate_case_prev); 906 // FIXME: We really want to remove the bogus case stmt from the 907 // substmt, but we have no way to do this right now. 908 CaseListIsErroneous = true; 909 } 910 } 911 } 912 913 // Complain if we have a constant condition and we didn't find a match. 914 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 915 // TODO: it would be nice if we printed enums as enums, chars as 916 // chars, etc. 917 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 918 << ConstantCondValue.toString(10) 919 << CondExpr->getSourceRange(); 920 } 921 922 // Check to see if switch is over an Enum and handles all of its 923 // values. We only issue a warning if there is not 'default:', but 924 // we still do the analysis to preserve this information in the AST 925 // (which can be used by flow-based analyes). 926 // 927 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 928 929 // If switch has default case, then ignore it. 930 if (!CaseListIsErroneous && !HasConstantCond && ET) { 931 const EnumDecl *ED = ET->getDecl(); 932 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 933 EnumValsTy; 934 EnumValsTy EnumVals; 935 936 // Gather all enum values, set their type and sort them, 937 // allowing easier comparison with CaseVals. 938 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 939 EDI != ED->enumerator_end(); ++EDI) { 940 llvm::APSInt Val = EDI->getInitVal(); 941 AdjustAPSInt(Val, CondWidth, CondIsSigned); 942 EnumVals.push_back(std::make_pair(Val, &*EDI)); 943 } 944 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 945 EnumValsTy::iterator EIend = 946 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 947 948 // See which case values aren't in enum. 949 EnumValsTy::const_iterator EI = EnumVals.begin(); 950 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 951 CI != CaseVals.end(); CI++) { 952 while (EI != EIend && EI->first < CI->first) 953 EI++; 954 if (EI == EIend || EI->first > CI->first) 955 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 956 << CondTypeBeforePromotion; 957 } 958 // See which of case ranges aren't in enum 959 EI = EnumVals.begin(); 960 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 961 RI != CaseRanges.end() && EI != EIend; RI++) { 962 while (EI != EIend && EI->first < RI->first) 963 EI++; 964 965 if (EI == EIend || EI->first != RI->first) { 966 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 967 << CondTypeBeforePromotion; 968 } 969 970 llvm::APSInt Hi = 971 RI->second->getRHS()->EvaluateKnownConstInt(Context); 972 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 973 while (EI != EIend && EI->first < Hi) 974 EI++; 975 if (EI == EIend || EI->first != Hi) 976 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 977 << CondTypeBeforePromotion; 978 } 979 980 // Check which enum vals aren't in switch 981 CaseValsTy::const_iterator CI = CaseVals.begin(); 982 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 983 bool hasCasesNotInSwitch = false; 984 985 SmallVector<DeclarationName,8> UnhandledNames; 986 987 for (EI = EnumVals.begin(); EI != EIend; EI++){ 988 // Drop unneeded case values 989 llvm::APSInt CIVal; 990 while (CI != CaseVals.end() && CI->first < EI->first) 991 CI++; 992 993 if (CI != CaseVals.end() && CI->first == EI->first) 994 continue; 995 996 // Drop unneeded case ranges 997 for (; RI != CaseRanges.end(); RI++) { 998 llvm::APSInt Hi = 999 RI->second->getRHS()->EvaluateKnownConstInt(Context); 1000 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 1001 if (EI->first <= Hi) 1002 break; 1003 } 1004 1005 if (RI == CaseRanges.end() || EI->first < RI->first) { 1006 hasCasesNotInSwitch = true; 1007 UnhandledNames.push_back(EI->second->getDeclName()); 1008 } 1009 } 1010 1011 if (TheDefaultStmt && UnhandledNames.empty()) 1012 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default); 1013 1014 // Produce a nice diagnostic if multiple values aren't handled. 1015 switch (UnhandledNames.size()) { 1016 case 0: break; 1017 case 1: 1018 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1019 ? diag::warn_def_missing_case1 : diag::warn_missing_case1) 1020 << UnhandledNames[0]; 1021 break; 1022 case 2: 1023 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1024 ? diag::warn_def_missing_case2 : diag::warn_missing_case2) 1025 << UnhandledNames[0] << UnhandledNames[1]; 1026 break; 1027 case 3: 1028 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1029 ? diag::warn_def_missing_case3 : diag::warn_missing_case3) 1030 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 1031 break; 1032 default: 1033 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1034 ? diag::warn_def_missing_cases : diag::warn_missing_cases) 1035 << (unsigned)UnhandledNames.size() 1036 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 1037 break; 1038 } 1039 1040 if (!hasCasesNotInSwitch) 1041 SS->setAllEnumCasesCovered(); 1042 } 1043 } 1044 1045 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt, 1046 diag::warn_empty_switch_body); 1047 1048 // FIXME: If the case list was broken is some way, we don't have a good system 1049 // to patch it up. Instead, just return the whole substmt as broken. 1050 if (CaseListIsErroneous) 1051 return StmtError(); 1052 1053 return Owned(SS); 1054} 1055 1056StmtResult 1057Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 1058 Decl *CondVar, Stmt *Body) { 1059 ExprResult CondResult(Cond.release()); 1060 1061 VarDecl *ConditionVar = 0; 1062 if (CondVar) { 1063 ConditionVar = cast<VarDecl>(CondVar); 1064 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 1065 if (CondResult.isInvalid()) 1066 return StmtError(); 1067 } 1068 Expr *ConditionExpr = CondResult.take(); 1069 if (!ConditionExpr) 1070 return StmtError(); 1071 1072 DiagnoseUnusedExprResult(Body); 1073 1074 if (isa<NullStmt>(Body)) 1075 getCurCompoundScope().setHasEmptyLoopBodies(); 1076 1077 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 1078 Body, WhileLoc)); 1079} 1080 1081StmtResult 1082Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 1083 SourceLocation WhileLoc, SourceLocation CondLParen, 1084 Expr *Cond, SourceLocation CondRParen) { 1085 assert(Cond && "ActOnDoStmt(): missing expression"); 1086 1087 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 1088 if (CondResult.isInvalid() || CondResult.isInvalid()) 1089 return StmtError(); 1090 Cond = CondResult.take(); 1091 1092 CheckImplicitConversions(Cond, DoLoc); 1093 CondResult = MaybeCreateExprWithCleanups(Cond); 1094 if (CondResult.isInvalid()) 1095 return StmtError(); 1096 Cond = CondResult.take(); 1097 1098 DiagnoseUnusedExprResult(Body); 1099 1100 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 1101} 1102 1103namespace { 1104 // This visitor will traverse a conditional statement and store all 1105 // the evaluated decls into a vector. Simple is set to true if none 1106 // of the excluded constructs are used. 1107 class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> { 1108 llvm::SmallPtrSet<VarDecl*, 8> &Decls; 1109 llvm::SmallVector<SourceRange, 10> &Ranges; 1110 bool Simple; 1111 PartialDiagnostic &PDiag; 1112public: 1113 typedef EvaluatedExprVisitor<DeclExtractor> Inherited; 1114 1115 DeclExtractor(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, 1116 llvm::SmallVector<SourceRange, 10> &Ranges, 1117 PartialDiagnostic &PDiag) : 1118 Inherited(S.Context), 1119 Decls(Decls), 1120 Ranges(Ranges), 1121 Simple(true), 1122 PDiag(PDiag) {} 1123 1124 bool isSimple() { return Simple; } 1125 1126 // Replaces the method in EvaluatedExprVisitor. 1127 void VisitMemberExpr(MemberExpr* E) { 1128 Simple = false; 1129 } 1130 1131 // Any Stmt not whitelisted will cause the condition to be marked complex. 1132 void VisitStmt(Stmt *S) { 1133 Simple = false; 1134 } 1135 1136 void VisitBinaryOperator(BinaryOperator *E) { 1137 Visit(E->getLHS()); 1138 Visit(E->getRHS()); 1139 } 1140 1141 void VisitCastExpr(CastExpr *E) { 1142 Visit(E->getSubExpr()); 1143 } 1144 1145 void VisitUnaryOperator(UnaryOperator *E) { 1146 // Skip checking conditionals with derefernces. 1147 if (E->getOpcode() == UO_Deref) 1148 Simple = false; 1149 else 1150 Visit(E->getSubExpr()); 1151 } 1152 1153 void VisitConditionalOperator(ConditionalOperator *E) { 1154 Visit(E->getCond()); 1155 Visit(E->getTrueExpr()); 1156 Visit(E->getFalseExpr()); 1157 } 1158 1159 void VisitParenExpr(ParenExpr *E) { 1160 Visit(E->getSubExpr()); 1161 } 1162 1163 void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) { 1164 Visit(E->getOpaqueValue()->getSourceExpr()); 1165 Visit(E->getFalseExpr()); 1166 } 1167 1168 void VisitIntegerLiteral(IntegerLiteral *E) { } 1169 void VisitFloatingLiteral(FloatingLiteral *E) { } 1170 void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { } 1171 void VisitCharacterLiteral(CharacterLiteral *E) { } 1172 void VisitGNUNullExpr(GNUNullExpr *E) { } 1173 void VisitImaginaryLiteral(ImaginaryLiteral *E) { } 1174 1175 void VisitDeclRefExpr(DeclRefExpr *E) { 1176 VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()); 1177 if (!VD) return; 1178 1179 Ranges.push_back(E->getSourceRange()); 1180 1181 Decls.insert(VD); 1182 } 1183 1184 }; // end class DeclExtractor 1185 1186 // DeclMatcher checks to see if the decls are used in a non-evauluated 1187 // context. 1188 class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> { 1189 llvm::SmallPtrSet<VarDecl*, 8> &Decls; 1190 bool FoundDecl; 1191 //bool EvalDecl; 1192 1193public: 1194 typedef EvaluatedExprVisitor<DeclMatcher> Inherited; 1195 1196 DeclMatcher(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, Stmt *Statement) : 1197 Inherited(S.Context), Decls(Decls), FoundDecl(false) { 1198 if (!Statement) return; 1199 1200 Visit(Statement); 1201 } 1202 1203 void VisitReturnStmt(ReturnStmt *S) { 1204 FoundDecl = true; 1205 } 1206 1207 void VisitBreakStmt(BreakStmt *S) { 1208 FoundDecl = true; 1209 } 1210 1211 void VisitGotoStmt(GotoStmt *S) { 1212 FoundDecl = true; 1213 } 1214 1215 void VisitCastExpr(CastExpr *E) { 1216 if (E->getCastKind() == CK_LValueToRValue) 1217 CheckLValueToRValueCast(E->getSubExpr()); 1218 else 1219 Visit(E->getSubExpr()); 1220 } 1221 1222 void CheckLValueToRValueCast(Expr *E) { 1223 E = E->IgnoreParenImpCasts(); 1224 1225 if (isa<DeclRefExpr>(E)) { 1226 return; 1227 } 1228 1229 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 1230 Visit(CO->getCond()); 1231 CheckLValueToRValueCast(CO->getTrueExpr()); 1232 CheckLValueToRValueCast(CO->getFalseExpr()); 1233 return; 1234 } 1235 1236 if (BinaryConditionalOperator *BCO = 1237 dyn_cast<BinaryConditionalOperator>(E)) { 1238 CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr()); 1239 CheckLValueToRValueCast(BCO->getFalseExpr()); 1240 return; 1241 } 1242 1243 Visit(E); 1244 } 1245 1246 void VisitDeclRefExpr(DeclRefExpr *E) { 1247 if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl())) 1248 if (Decls.count(VD)) 1249 FoundDecl = true; 1250 } 1251 1252 bool FoundDeclInUse() { return FoundDecl; } 1253 1254 }; // end class DeclMatcher 1255 1256 void CheckForLoopConditionalStatement(Sema &S, Expr *Second, 1257 Expr *Third, Stmt *Body) { 1258 // Condition is empty 1259 if (!Second) return; 1260 1261 if (S.Diags.getDiagnosticLevel(diag::warn_variables_not_in_loop_body, 1262 Second->getLocStart()) 1263 == DiagnosticsEngine::Ignored) 1264 return; 1265 1266 PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body); 1267 llvm::SmallPtrSet<VarDecl*, 8> Decls; 1268 llvm::SmallVector<SourceRange, 10> Ranges; 1269 DeclExtractor DE(S, Decls, Ranges, PDiag); 1270 DE.Visit(Second); 1271 1272 // Don't analyze complex conditionals. 1273 if (!DE.isSimple()) return; 1274 1275 // No decls found. 1276 if (Decls.size() == 0) return; 1277 1278 // Don't warn on volatile, static, or global variables. 1279 for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(), 1280 E = Decls.end(); 1281 I != E; ++I) 1282 if ((*I)->getType().isVolatileQualified() || 1283 (*I)->hasGlobalStorage()) return; 1284 1285 if (DeclMatcher(S, Decls, Second).FoundDeclInUse() || 1286 DeclMatcher(S, Decls, Third).FoundDeclInUse() || 1287 DeclMatcher(S, Decls, Body).FoundDeclInUse()) 1288 return; 1289 1290 // Load decl names into diagnostic. 1291 if (Decls.size() > 4) 1292 PDiag << 0; 1293 else { 1294 PDiag << Decls.size(); 1295 for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(), 1296 E = Decls.end(); 1297 I != E; ++I) 1298 PDiag << (*I)->getDeclName(); 1299 } 1300 1301 // Load SourceRanges into diagnostic if there is room. 1302 // Otherwise, load the SourceRange of the conditional expression. 1303 if (Ranges.size() <= PartialDiagnostic::MaxArguments) 1304 for (llvm::SmallVector<SourceRange, 10>::iterator I = Ranges.begin(), 1305 E = Ranges.end(); 1306 I != E; ++I) 1307 PDiag << *I; 1308 else 1309 PDiag << Second->getSourceRange(); 1310 1311 S.Diag(Ranges.begin()->getBegin(), PDiag); 1312 } 1313 1314} // end namespace 1315 1316StmtResult 1317Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1318 Stmt *First, FullExprArg second, Decl *secondVar, 1319 FullExprArg third, 1320 SourceLocation RParenLoc, Stmt *Body) { 1321 if (!getLangOpts().CPlusPlus) { 1322 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 1323 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1324 // declare identifiers for objects having storage class 'auto' or 1325 // 'register'. 1326 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 1327 DI!=DE; ++DI) { 1328 VarDecl *VD = dyn_cast<VarDecl>(*DI); 1329 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 1330 VD = 0; 1331 if (VD == 0) 1332 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 1333 // FIXME: mark decl erroneous! 1334 } 1335 } 1336 } 1337 1338 CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body); 1339 1340 ExprResult SecondResult(second.release()); 1341 VarDecl *ConditionVar = 0; 1342 if (secondVar) { 1343 ConditionVar = cast<VarDecl>(secondVar); 1344 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1345 if (SecondResult.isInvalid()) 1346 return StmtError(); 1347 } 1348 1349 Expr *Third = third.release().takeAs<Expr>(); 1350 1351 DiagnoseUnusedExprResult(First); 1352 DiagnoseUnusedExprResult(Third); 1353 DiagnoseUnusedExprResult(Body); 1354 1355 if (isa<NullStmt>(Body)) 1356 getCurCompoundScope().setHasEmptyLoopBodies(); 1357 1358 return Owned(new (Context) ForStmt(Context, First, 1359 SecondResult.take(), ConditionVar, 1360 Third, Body, ForLoc, LParenLoc, 1361 RParenLoc)); 1362} 1363 1364/// In an Objective C collection iteration statement: 1365/// for (x in y) 1366/// x can be an arbitrary l-value expression. Bind it up as a 1367/// full-expression. 1368StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1369 // Reduce placeholder expressions here. Note that this rejects the 1370 // use of pseudo-object l-values in this position. 1371 ExprResult result = CheckPlaceholderExpr(E); 1372 if (result.isInvalid()) return StmtError(); 1373 E = result.take(); 1374 1375 CheckImplicitConversions(E); 1376 1377 result = MaybeCreateExprWithCleanups(E); 1378 if (result.isInvalid()) return StmtError(); 1379 1380 return Owned(static_cast<Stmt*>(result.take())); 1381} 1382 1383ExprResult 1384Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1385 assert(collection); 1386 1387 // Bail out early if we've got a type-dependent expression. 1388 if (collection->isTypeDependent()) return Owned(collection); 1389 1390 // Perform normal l-value conversion. 1391 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1392 if (result.isInvalid()) 1393 return ExprError(); 1394 collection = result.take(); 1395 1396 // The operand needs to have object-pointer type. 1397 // TODO: should we do a contextual conversion? 1398 const ObjCObjectPointerType *pointerType = 1399 collection->getType()->getAs<ObjCObjectPointerType>(); 1400 if (!pointerType) 1401 return Diag(forLoc, diag::err_collection_expr_type) 1402 << collection->getType() << collection->getSourceRange(); 1403 1404 // Check that the operand provides 1405 // - countByEnumeratingWithState:objects:count: 1406 const ObjCObjectType *objectType = pointerType->getObjectType(); 1407 ObjCInterfaceDecl *iface = objectType->getInterface(); 1408 1409 // If we have a forward-declared type, we can't do this check. 1410 // Under ARC, it is an error not to have a forward-declared class. 1411 if (iface && 1412 RequireCompleteType(forLoc, QualType(objectType, 0), 1413 getLangOpts().ObjCAutoRefCount 1414 ? diag::err_arc_collection_forward 1415 : 0, 1416 collection)) { 1417 // Otherwise, if we have any useful type information, check that 1418 // the type declares the appropriate method. 1419 } else if (iface || !objectType->qual_empty()) { 1420 IdentifierInfo *selectorIdents[] = { 1421 &Context.Idents.get("countByEnumeratingWithState"), 1422 &Context.Idents.get("objects"), 1423 &Context.Idents.get("count") 1424 }; 1425 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1426 1427 ObjCMethodDecl *method = 0; 1428 1429 // If there's an interface, look in both the public and private APIs. 1430 if (iface) { 1431 method = iface->lookupInstanceMethod(selector); 1432 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1433 } 1434 1435 // Also check protocol qualifiers. 1436 if (!method) 1437 method = LookupMethodInQualifiedType(selector, pointerType, 1438 /*instance*/ true); 1439 1440 // If we didn't find it anywhere, give up. 1441 if (!method) { 1442 Diag(forLoc, diag::warn_collection_expr_type) 1443 << collection->getType() << selector << collection->getSourceRange(); 1444 } 1445 1446 // TODO: check for an incompatible signature? 1447 } 1448 1449 // Wrap up any cleanups in the expression. 1450 return Owned(MaybeCreateExprWithCleanups(collection)); 1451} 1452 1453StmtResult 1454Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1455 SourceLocation LParenLoc, 1456 Stmt *First, Expr *Second, 1457 SourceLocation RParenLoc, Stmt *Body) { 1458 if (First) { 1459 QualType FirstType; 1460 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1461 if (!DS->isSingleDecl()) 1462 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1463 diag::err_toomany_element_decls)); 1464 1465 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1466 FirstType = D->getType(); 1467 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1468 // declare identifiers for objects having storage class 'auto' or 1469 // 'register'. 1470 if (!D->hasLocalStorage()) 1471 return StmtError(Diag(D->getLocation(), 1472 diag::err_non_variable_decl_in_for)); 1473 } else { 1474 Expr *FirstE = cast<Expr>(First); 1475 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1476 return StmtError(Diag(First->getLocStart(), 1477 diag::err_selector_element_not_lvalue) 1478 << First->getSourceRange()); 1479 1480 FirstType = static_cast<Expr*>(First)->getType(); 1481 } 1482 if (!FirstType->isDependentType() && 1483 !FirstType->isObjCObjectPointerType() && 1484 !FirstType->isBlockPointerType()) 1485 Diag(ForLoc, diag::err_selector_element_type) 1486 << FirstType << First->getSourceRange(); 1487 } 1488 1489 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1490 ForLoc, RParenLoc)); 1491} 1492 1493namespace { 1494 1495enum BeginEndFunction { 1496 BEF_begin, 1497 BEF_end 1498}; 1499 1500/// Build a variable declaration for a for-range statement. 1501static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1502 QualType Type, const char *Name) { 1503 DeclContext *DC = SemaRef.CurContext; 1504 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1505 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1506 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1507 TInfo, SC_Auto, SC_None); 1508 Decl->setImplicit(); 1509 return Decl; 1510} 1511 1512/// Finish building a variable declaration for a for-range statement. 1513/// \return true if an error occurs. 1514static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1515 SourceLocation Loc, int diag) { 1516 // Deduce the type for the iterator variable now rather than leaving it to 1517 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1518 TypeSourceInfo *InitTSI = 0; 1519 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) || 1520 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) == 1521 Sema::DAR_Failed) 1522 SemaRef.Diag(Loc, diag) << Init->getType(); 1523 if (!InitTSI) { 1524 Decl->setInvalidDecl(); 1525 return true; 1526 } 1527 Decl->setTypeSourceInfo(InitTSI); 1528 Decl->setType(InitTSI->getType()); 1529 1530 // In ARC, infer lifetime. 1531 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1532 // we're doing the equivalent of fast iteration. 1533 if (SemaRef.getLangOpts().ObjCAutoRefCount && 1534 SemaRef.inferObjCARCLifetime(Decl)) 1535 Decl->setInvalidDecl(); 1536 1537 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1538 /*TypeMayContainAuto=*/false); 1539 SemaRef.FinalizeDeclaration(Decl); 1540 SemaRef.CurContext->addHiddenDecl(Decl); 1541 return false; 1542} 1543 1544/// Produce a note indicating which begin/end function was implicitly called 1545/// by a C++0x for-range statement. This is often not obvious from the code, 1546/// nor from the diagnostics produced when analysing the implicit expressions 1547/// required in a for-range statement. 1548void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1549 BeginEndFunction BEF) { 1550 CallExpr *CE = dyn_cast<CallExpr>(E); 1551 if (!CE) 1552 return; 1553 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1554 if (!D) 1555 return; 1556 SourceLocation Loc = D->getLocation(); 1557 1558 std::string Description; 1559 bool IsTemplate = false; 1560 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1561 Description = SemaRef.getTemplateArgumentBindingsText( 1562 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1563 IsTemplate = true; 1564 } 1565 1566 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1567 << BEF << IsTemplate << Description << E->getType(); 1568} 1569 1570/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1571/// given LookupResult is non-empty, it is assumed to describe a member which 1572/// will be invoked. Otherwise, the function will be found via argument 1573/// dependent lookup. 1574static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1575 SourceLocation Loc, 1576 VarDecl *Decl, 1577 BeginEndFunction BEF, 1578 const DeclarationNameInfo &NameInfo, 1579 LookupResult &MemberLookup, 1580 Expr *Range) { 1581 ExprResult CallExpr; 1582 if (!MemberLookup.empty()) { 1583 ExprResult MemberRef = 1584 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1585 /*IsPtr=*/false, CXXScopeSpec(), 1586 /*TemplateKWLoc=*/SourceLocation(), 1587 /*FirstQualifierInScope=*/0, 1588 MemberLookup, 1589 /*TemplateArgs=*/0); 1590 if (MemberRef.isInvalid()) 1591 return ExprError(); 1592 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1593 Loc, 0); 1594 if (CallExpr.isInvalid()) 1595 return ExprError(); 1596 } else { 1597 UnresolvedSet<0> FoundNames; 1598 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1599 // std is an associated namespace. 1600 UnresolvedLookupExpr *Fn = 1601 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1602 NestedNameSpecifierLoc(), NameInfo, 1603 /*NeedsADL=*/true, /*Overloaded=*/false, 1604 FoundNames.begin(), FoundNames.end(), 1605 /*LookInStdNamespace=*/true); 1606 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1607 0, /*AllowTypoCorrection=*/false); 1608 if (CallExpr.isInvalid()) { 1609 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1610 << Range->getType(); 1611 return ExprError(); 1612 } 1613 } 1614 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1615 diag::err_for_range_iter_deduction_failure)) { 1616 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1617 return ExprError(); 1618 } 1619 return CallExpr; 1620} 1621 1622} 1623 1624/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1625/// 1626/// C++0x [stmt.ranged]: 1627/// A range-based for statement is equivalent to 1628/// 1629/// { 1630/// auto && __range = range-init; 1631/// for ( auto __begin = begin-expr, 1632/// __end = end-expr; 1633/// __begin != __end; 1634/// ++__begin ) { 1635/// for-range-declaration = *__begin; 1636/// statement 1637/// } 1638/// } 1639/// 1640/// The body of the loop is not available yet, since it cannot be analysed until 1641/// we have determined the type of the for-range-declaration. 1642StmtResult 1643Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1644 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1645 SourceLocation RParenLoc) { 1646 if (!First || !Range) 1647 return StmtError(); 1648 1649 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1650 assert(DS && "first part of for range not a decl stmt"); 1651 1652 if (!DS->isSingleDecl()) { 1653 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1654 return StmtError(); 1655 } 1656 if (DS->getSingleDecl()->isInvalidDecl()) 1657 return StmtError(); 1658 1659 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1660 return StmtError(); 1661 1662 // Build auto && __range = range-init 1663 SourceLocation RangeLoc = Range->getLocStart(); 1664 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1665 Context.getAutoRRefDeductType(), 1666 "__range"); 1667 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1668 diag::err_for_range_deduction_failure)) 1669 return StmtError(); 1670 1671 // Claim the type doesn't contain auto: we've already done the checking. 1672 DeclGroupPtrTy RangeGroup = 1673 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1674 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1675 if (RangeDecl.isInvalid()) 1676 return StmtError(); 1677 1678 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1679 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1680 RParenLoc); 1681} 1682 1683/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1684StmtResult 1685Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1686 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1687 Expr *Inc, Stmt *LoopVarDecl, 1688 SourceLocation RParenLoc) { 1689 Scope *S = getCurScope(); 1690 1691 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1692 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1693 QualType RangeVarType = RangeVar->getType(); 1694 1695 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1696 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1697 1698 StmtResult BeginEndDecl = BeginEnd; 1699 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1700 1701 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1702 SourceLocation RangeLoc = RangeVar->getLocation(); 1703 1704 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1705 1706 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1707 VK_LValue, ColonLoc); 1708 if (BeginRangeRef.isInvalid()) 1709 return StmtError(); 1710 1711 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1712 VK_LValue, ColonLoc); 1713 if (EndRangeRef.isInvalid()) 1714 return StmtError(); 1715 1716 QualType AutoType = Context.getAutoDeductType(); 1717 Expr *Range = RangeVar->getInit(); 1718 if (!Range) 1719 return StmtError(); 1720 QualType RangeType = Range->getType(); 1721 1722 if (RequireCompleteType(RangeLoc, RangeType, 1723 diag::err_for_range_incomplete_type)) 1724 return StmtError(); 1725 1726 // Build auto __begin = begin-expr, __end = end-expr. 1727 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1728 "__begin"); 1729 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1730 "__end"); 1731 1732 // Build begin-expr and end-expr and attach to __begin and __end variables. 1733 ExprResult BeginExpr, EndExpr; 1734 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1735 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1736 // __range + __bound, respectively, where __bound is the array bound. If 1737 // _RangeT is an array of unknown size or an array of incomplete type, 1738 // the program is ill-formed; 1739 1740 // begin-expr is __range. 1741 BeginExpr = BeginRangeRef; 1742 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1743 diag::err_for_range_iter_deduction_failure)) { 1744 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1745 return StmtError(); 1746 } 1747 1748 // Find the array bound. 1749 ExprResult BoundExpr; 1750 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1751 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1752 Context.getPointerDiffType(), 1753 RangeLoc)); 1754 else if (const VariableArrayType *VAT = 1755 dyn_cast<VariableArrayType>(UnqAT)) 1756 BoundExpr = VAT->getSizeExpr(); 1757 else { 1758 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1759 // UnqAT is not incomplete and Range is not type-dependent. 1760 llvm_unreachable("Unexpected array type in for-range"); 1761 } 1762 1763 // end-expr is __range + __bound. 1764 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1765 BoundExpr.get()); 1766 if (EndExpr.isInvalid()) 1767 return StmtError(); 1768 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1769 diag::err_for_range_iter_deduction_failure)) { 1770 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1771 return StmtError(); 1772 } 1773 } else { 1774 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1775 ColonLoc); 1776 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1777 ColonLoc); 1778 1779 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1780 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1781 1782 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1783 // - if _RangeT is a class type, the unqualified-ids begin and end are 1784 // looked up in the scope of class _RangeT as if by class member access 1785 // lookup (3.4.5), and if either (or both) finds at least one 1786 // declaration, begin-expr and end-expr are __range.begin() and 1787 // __range.end(), respectively; 1788 LookupQualifiedName(BeginMemberLookup, D); 1789 LookupQualifiedName(EndMemberLookup, D); 1790 1791 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1792 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1793 << RangeType << BeginMemberLookup.empty(); 1794 return StmtError(); 1795 } 1796 } else { 1797 // - otherwise, begin-expr and end-expr are begin(__range) and 1798 // end(__range), respectively, where begin and end are looked up with 1799 // argument-dependent lookup (3.4.2). For the purposes of this name 1800 // lookup, namespace std is an associated namespace. 1801 } 1802 1803 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1804 BEF_begin, BeginNameInfo, 1805 BeginMemberLookup, 1806 BeginRangeRef.get()); 1807 if (BeginExpr.isInvalid()) 1808 return StmtError(); 1809 1810 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1811 BEF_end, EndNameInfo, 1812 EndMemberLookup, EndRangeRef.get()); 1813 if (EndExpr.isInvalid()) 1814 return StmtError(); 1815 } 1816 1817 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1818 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1819 if (!Context.hasSameType(BeginType, EndType)) { 1820 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1821 << BeginType << EndType; 1822 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1823 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1824 } 1825 1826 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1827 // Claim the type doesn't contain auto: we've already done the checking. 1828 DeclGroupPtrTy BeginEndGroup = 1829 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1830 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1831 1832 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1833 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1834 VK_LValue, ColonLoc); 1835 if (BeginRef.isInvalid()) 1836 return StmtError(); 1837 1838 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1839 VK_LValue, ColonLoc); 1840 if (EndRef.isInvalid()) 1841 return StmtError(); 1842 1843 // Build and check __begin != __end expression. 1844 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1845 BeginRef.get(), EndRef.get()); 1846 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1847 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1848 if (NotEqExpr.isInvalid()) { 1849 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1850 if (!Context.hasSameType(BeginType, EndType)) 1851 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1852 return StmtError(); 1853 } 1854 1855 // Build and check ++__begin expression. 1856 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1857 VK_LValue, ColonLoc); 1858 if (BeginRef.isInvalid()) 1859 return StmtError(); 1860 1861 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1862 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1863 if (IncrExpr.isInvalid()) { 1864 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1865 return StmtError(); 1866 } 1867 1868 // Build and check *__begin expression. 1869 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1870 VK_LValue, ColonLoc); 1871 if (BeginRef.isInvalid()) 1872 return StmtError(); 1873 1874 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1875 if (DerefExpr.isInvalid()) { 1876 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1877 return StmtError(); 1878 } 1879 1880 // Attach *__begin as initializer for VD. 1881 if (!LoopVar->isInvalidDecl()) { 1882 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1883 /*TypeMayContainAuto=*/true); 1884 if (LoopVar->isInvalidDecl()) 1885 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1886 } 1887 } else { 1888 // The range is implicitly used as a placeholder when it is dependent. 1889 RangeVar->setUsed(); 1890 } 1891 1892 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1893 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1894 NotEqExpr.take(), IncrExpr.take(), 1895 LoopVarDS, /*Body=*/0, ForLoc, 1896 ColonLoc, RParenLoc)); 1897} 1898 1899/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1900/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1901/// body cannot be performed until after the type of the range variable is 1902/// determined. 1903StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1904 if (!S || !B) 1905 return StmtError(); 1906 1907 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S); 1908 ForStmt->setBody(B); 1909 1910 DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B, 1911 diag::warn_empty_range_based_for_body); 1912 1913 return S; 1914} 1915 1916StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1917 SourceLocation LabelLoc, 1918 LabelDecl *TheDecl) { 1919 getCurFunction()->setHasBranchIntoScope(); 1920 TheDecl->setUsed(); 1921 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1922} 1923 1924StmtResult 1925Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1926 Expr *E) { 1927 // Convert operand to void* 1928 if (!E->isTypeDependent()) { 1929 QualType ETy = E->getType(); 1930 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1931 ExprResult ExprRes = Owned(E); 1932 AssignConvertType ConvTy = 1933 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1934 if (ExprRes.isInvalid()) 1935 return StmtError(); 1936 E = ExprRes.take(); 1937 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1938 return StmtError(); 1939 E = MaybeCreateExprWithCleanups(E); 1940 } 1941 1942 getCurFunction()->setHasIndirectGoto(); 1943 1944 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1945} 1946 1947StmtResult 1948Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1949 Scope *S = CurScope->getContinueParent(); 1950 if (!S) { 1951 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1952 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1953 } 1954 1955 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1956} 1957 1958StmtResult 1959Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1960 Scope *S = CurScope->getBreakParent(); 1961 if (!S) { 1962 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1963 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1964 } 1965 1966 return Owned(new (Context) BreakStmt(BreakLoc)); 1967} 1968 1969/// \brief Determine whether the given expression is a candidate for 1970/// copy elision in either a return statement or a throw expression. 1971/// 1972/// \param ReturnType If we're determining the copy elision candidate for 1973/// a return statement, this is the return type of the function. If we're 1974/// determining the copy elision candidate for a throw expression, this will 1975/// be a NULL type. 1976/// 1977/// \param E The expression being returned from the function or block, or 1978/// being thrown. 1979/// 1980/// \param AllowFunctionParameter Whether we allow function parameters to 1981/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1982/// we re-use this logic to determine whether we should try to move as part of 1983/// a return or throw (which does allow function parameters). 1984/// 1985/// \returns The NRVO candidate variable, if the return statement may use the 1986/// NRVO, or NULL if there is no such candidate. 1987const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1988 Expr *E, 1989 bool AllowFunctionParameter) { 1990 QualType ExprType = E->getType(); 1991 // - in a return statement in a function with ... 1992 // ... a class return type ... 1993 if (!ReturnType.isNull()) { 1994 if (!ReturnType->isRecordType()) 1995 return 0; 1996 // ... the same cv-unqualified type as the function return type ... 1997 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1998 return 0; 1999 } 2000 2001 // ... the expression is the name of a non-volatile automatic object 2002 // (other than a function or catch-clause parameter)) ... 2003 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 2004 if (!DR) 2005 return 0; 2006 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 2007 if (!VD) 2008 return 0; 2009 2010 // ...object (other than a function or catch-clause parameter)... 2011 if (VD->getKind() != Decl::Var && 2012 !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) 2013 return 0; 2014 if (VD->isExceptionVariable()) return 0; 2015 2016 // ...automatic... 2017 if (!VD->hasLocalStorage()) return 0; 2018 2019 // ...non-volatile... 2020 if (VD->getType().isVolatileQualified()) return 0; 2021 if (VD->getType()->isReferenceType()) return 0; 2022 2023 // __block variables can't be allocated in a way that permits NRVO. 2024 if (VD->hasAttr<BlocksAttr>()) return 0; 2025 2026 // Variables with higher required alignment than their type's ABI 2027 // alignment cannot use NRVO. 2028 if (VD->hasAttr<AlignedAttr>() && 2029 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) 2030 return 0; 2031 2032 return VD; 2033} 2034 2035/// \brief Perform the initialization of a potentially-movable value, which 2036/// is the result of return value. 2037/// 2038/// This routine implements C++0x [class.copy]p33, which attempts to treat 2039/// returned lvalues as rvalues in certain cases (to prefer move construction), 2040/// then falls back to treating them as lvalues if that failed. 2041ExprResult 2042Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 2043 const VarDecl *NRVOCandidate, 2044 QualType ResultType, 2045 Expr *Value, 2046 bool AllowNRVO) { 2047 // C++0x [class.copy]p33: 2048 // When the criteria for elision of a copy operation are met or would 2049 // be met save for the fact that the source object is a function 2050 // parameter, and the object to be copied is designated by an lvalue, 2051 // overload resolution to select the constructor for the copy is first 2052 // performed as if the object were designated by an rvalue. 2053 ExprResult Res = ExprError(); 2054 if (AllowNRVO && 2055 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 2056 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 2057 Value->getType(), CK_NoOp, Value, VK_XValue); 2058 2059 Expr *InitExpr = &AsRvalue; 2060 InitializationKind Kind 2061 = InitializationKind::CreateCopy(Value->getLocStart(), 2062 Value->getLocStart()); 2063 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 2064 2065 // [...] If overload resolution fails, or if the type of the first 2066 // parameter of the selected constructor is not an rvalue reference 2067 // to the object's type (possibly cv-qualified), overload resolution 2068 // is performed again, considering the object as an lvalue. 2069 if (Seq) { 2070 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 2071 StepEnd = Seq.step_end(); 2072 Step != StepEnd; ++Step) { 2073 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 2074 continue; 2075 2076 CXXConstructorDecl *Constructor 2077 = cast<CXXConstructorDecl>(Step->Function.Function); 2078 2079 const RValueReferenceType *RRefType 2080 = Constructor->getParamDecl(0)->getType() 2081 ->getAs<RValueReferenceType>(); 2082 2083 // If we don't meet the criteria, break out now. 2084 if (!RRefType || 2085 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 2086 Context.getTypeDeclType(Constructor->getParent()))) 2087 break; 2088 2089 // Promote "AsRvalue" to the heap, since we now need this 2090 // expression node to persist. 2091 Value = ImplicitCastExpr::Create(Context, Value->getType(), 2092 CK_NoOp, Value, 0, VK_XValue); 2093 2094 // Complete type-checking the initialization of the return type 2095 // using the constructor we found. 2096 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 2097 } 2098 } 2099 } 2100 2101 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 2102 // above, or overload resolution failed. Either way, we need to try 2103 // (again) now with the return value expression as written. 2104 if (Res.isInvalid()) 2105 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 2106 2107 return Res; 2108} 2109 2110/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements 2111/// for capturing scopes. 2112/// 2113StmtResult 2114Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 2115 // If this is the first return we've seen, infer the return type. 2116 // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those 2117 // rules which allows multiple return statements. 2118 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction()); 2119 if (CurCap->HasImplicitReturnType) { 2120 QualType ReturnT; 2121 if (RetValExp && !isa<InitListExpr>(RetValExp)) { 2122 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 2123 if (Result.isInvalid()) 2124 return StmtError(); 2125 RetValExp = Result.take(); 2126 2127 if (!RetValExp->isTypeDependent()) 2128 ReturnT = RetValExp->getType(); 2129 else 2130 ReturnT = Context.DependentTy; 2131 } else { 2132 if (RetValExp) { 2133 // C++11 [expr.lambda.prim]p4 bans inferring the result from an 2134 // initializer list, because it is not an expression (even 2135 // though we represent it as one). We still deduce 'void'. 2136 Diag(ReturnLoc, diag::err_lambda_return_init_list) 2137 << RetValExp->getSourceRange(); 2138 } 2139 2140 ReturnT = Context.VoidTy; 2141 } 2142 // We require the return types to strictly match here. 2143 if (!CurCap->ReturnType.isNull() && 2144 !CurCap->ReturnType->isDependentType() && 2145 !ReturnT->isDependentType() && 2146 !Context.hasSameType(ReturnT, CurCap->ReturnType)) { 2147 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) 2148 << ReturnT << CurCap->ReturnType 2149 << (getCurLambda() != 0); 2150 return StmtError(); 2151 } 2152 CurCap->ReturnType = ReturnT; 2153 } 2154 QualType FnRetType = CurCap->ReturnType; 2155 assert(!FnRetType.isNull()); 2156 2157 if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) { 2158 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 2159 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr); 2160 return StmtError(); 2161 } 2162 } else { 2163 LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CurCap); 2164 if (LSI->CallOperator->getType()->getAs<FunctionType>()->getNoReturnAttr()){ 2165 Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr); 2166 return StmtError(); 2167 } 2168 } 2169 2170 // Otherwise, verify that this result type matches the previous one. We are 2171 // pickier with blocks than for normal functions because we don't have GCC 2172 // compatibility to worry about here. 2173 const VarDecl *NRVOCandidate = 0; 2174 if (FnRetType->isDependentType()) { 2175 // Delay processing for now. TODO: there are lots of dependent 2176 // types we can conclusively prove aren't void. 2177 } else if (FnRetType->isVoidType()) { 2178 if (RetValExp && !isa<InitListExpr>(RetValExp) && 2179 !(getLangOpts().CPlusPlus && 2180 (RetValExp->isTypeDependent() || 2181 RetValExp->getType()->isVoidType()))) { 2182 if (!getLangOpts().CPlusPlus && 2183 RetValExp->getType()->isVoidType()) 2184 Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2; 2185 else { 2186 Diag(ReturnLoc, diag::err_return_block_has_expr); 2187 RetValExp = 0; 2188 } 2189 } 2190 } else if (!RetValExp) { 2191 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 2192 } else if (!RetValExp->isTypeDependent()) { 2193 // we have a non-void block with an expression, continue checking 2194 2195 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2196 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2197 // function return. 2198 2199 // In C++ the return statement is handled via a copy initialization. 2200 // the C version of which boils down to CheckSingleAssignmentConstraints. 2201 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2202 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2203 FnRetType, 2204 NRVOCandidate != 0); 2205 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2206 FnRetType, RetValExp); 2207 if (Res.isInvalid()) { 2208 // FIXME: Cleanup temporaries here, anyway? 2209 return StmtError(); 2210 } 2211 RetValExp = Res.take(); 2212 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2213 } 2214 2215 if (RetValExp) { 2216 CheckImplicitConversions(RetValExp, ReturnLoc); 2217 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2218 } 2219 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 2220 NRVOCandidate); 2221 2222 // If we need to check for the named return value optimization, save the 2223 // return statement in our scope for later processing. 2224 if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 2225 !CurContext->isDependentContext()) 2226 FunctionScopes.back()->Returns.push_back(Result); 2227 2228 return Owned(Result); 2229} 2230 2231StmtResult 2232Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 2233 // Check for unexpanded parameter packs. 2234 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 2235 return StmtError(); 2236 2237 if (isa<CapturingScopeInfo>(getCurFunction())) 2238 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp); 2239 2240 QualType FnRetType; 2241 QualType RelatedRetType; 2242 if (const FunctionDecl *FD = getCurFunctionDecl()) { 2243 FnRetType = FD->getResultType(); 2244 if (FD->hasAttr<NoReturnAttr>() || 2245 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 2246 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 2247 << FD->getDeclName(); 2248 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 2249 FnRetType = MD->getResultType(); 2250 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 2251 // In the implementation of a method with a related return type, the 2252 // type used to type-check the validity of return statements within the 2253 // method body is a pointer to the type of the class being implemented. 2254 RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 2255 RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType); 2256 } 2257 } else // If we don't have a function/method context, bail. 2258 return StmtError(); 2259 2260 ReturnStmt *Result = 0; 2261 if (FnRetType->isVoidType()) { 2262 if (RetValExp) { 2263 if (isa<InitListExpr>(RetValExp)) { 2264 // We simply never allow init lists as the return value of void 2265 // functions. This is compatible because this was never allowed before, 2266 // so there's no legacy code to deal with. 2267 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2268 int FunctionKind = 0; 2269 if (isa<ObjCMethodDecl>(CurDecl)) 2270 FunctionKind = 1; 2271 else if (isa<CXXConstructorDecl>(CurDecl)) 2272 FunctionKind = 2; 2273 else if (isa<CXXDestructorDecl>(CurDecl)) 2274 FunctionKind = 3; 2275 2276 Diag(ReturnLoc, diag::err_return_init_list) 2277 << CurDecl->getDeclName() << FunctionKind 2278 << RetValExp->getSourceRange(); 2279 2280 // Drop the expression. 2281 RetValExp = 0; 2282 } else if (!RetValExp->isTypeDependent()) { 2283 // C99 6.8.6.4p1 (ext_ since GCC warns) 2284 unsigned D = diag::ext_return_has_expr; 2285 if (RetValExp->getType()->isVoidType()) 2286 D = diag::ext_return_has_void_expr; 2287 else { 2288 ExprResult Result = Owned(RetValExp); 2289 Result = IgnoredValueConversions(Result.take()); 2290 if (Result.isInvalid()) 2291 return StmtError(); 2292 RetValExp = Result.take(); 2293 RetValExp = ImpCastExprToType(RetValExp, 2294 Context.VoidTy, CK_ToVoid).take(); 2295 } 2296 2297 // return (some void expression); is legal in C++. 2298 if (D != diag::ext_return_has_void_expr || 2299 !getLangOpts().CPlusPlus) { 2300 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2301 2302 int FunctionKind = 0; 2303 if (isa<ObjCMethodDecl>(CurDecl)) 2304 FunctionKind = 1; 2305 else if (isa<CXXConstructorDecl>(CurDecl)) 2306 FunctionKind = 2; 2307 else if (isa<CXXDestructorDecl>(CurDecl)) 2308 FunctionKind = 3; 2309 2310 Diag(ReturnLoc, D) 2311 << CurDecl->getDeclName() << FunctionKind 2312 << RetValExp->getSourceRange(); 2313 } 2314 } 2315 2316 if (RetValExp) { 2317 CheckImplicitConversions(RetValExp, ReturnLoc); 2318 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2319 } 2320 } 2321 2322 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 2323 } else if (!RetValExp && !FnRetType->isDependentType()) { 2324 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 2325 // C99 6.8.6.4p1 (ext_ since GCC warns) 2326 if (getLangOpts().C99) DiagID = diag::ext_return_missing_expr; 2327 2328 if (FunctionDecl *FD = getCurFunctionDecl()) 2329 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 2330 else 2331 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 2332 Result = new (Context) ReturnStmt(ReturnLoc); 2333 } else { 2334 const VarDecl *NRVOCandidate = 0; 2335 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 2336 // we have a non-void function with an expression, continue checking 2337 2338 if (!RelatedRetType.isNull()) { 2339 // If we have a related result type, perform an extra conversion here. 2340 // FIXME: The diagnostics here don't really describe what is happening. 2341 InitializedEntity Entity = 2342 InitializedEntity::InitializeTemporary(RelatedRetType); 2343 2344 ExprResult Res = PerformCopyInitialization(Entity, SourceLocation(), 2345 RetValExp); 2346 if (Res.isInvalid()) { 2347 // FIXME: Cleanup temporaries here, anyway? 2348 return StmtError(); 2349 } 2350 RetValExp = Res.takeAs<Expr>(); 2351 } 2352 2353 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2354 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2355 // function return. 2356 2357 // In C++ the return statement is handled via a copy initialization, 2358 // the C version of which boils down to CheckSingleAssignmentConstraints. 2359 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2360 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2361 FnRetType, 2362 NRVOCandidate != 0); 2363 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2364 FnRetType, RetValExp); 2365 if (Res.isInvalid()) { 2366 // FIXME: Cleanup temporaries here, anyway? 2367 return StmtError(); 2368 } 2369 2370 RetValExp = Res.takeAs<Expr>(); 2371 if (RetValExp) 2372 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2373 } 2374 2375 if (RetValExp) { 2376 CheckImplicitConversions(RetValExp, ReturnLoc); 2377 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2378 } 2379 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 2380 } 2381 2382 // If we need to check for the named return value optimization, save the 2383 // return statement in our scope for later processing. 2384 if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 2385 !CurContext->isDependentContext()) 2386 FunctionScopes.back()->Returns.push_back(Result); 2387 2388 return Owned(Result); 2389} 2390 2391/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 2392/// ignore "noop" casts in places where an lvalue is required by an inline asm. 2393/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 2394/// provide a strong guidance to not use it. 2395/// 2396/// This method checks to see if the argument is an acceptable l-value and 2397/// returns false if it is a case we can handle. 2398static bool CheckAsmLValue(const Expr *E, Sema &S) { 2399 // Type dependent expressions will be checked during instantiation. 2400 if (E->isTypeDependent()) 2401 return false; 2402 2403 if (E->isLValue()) 2404 return false; // Cool, this is an lvalue. 2405 2406 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 2407 // are supposed to allow. 2408 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 2409 if (E != E2 && E2->isLValue()) { 2410 if (!S.getLangOpts().HeinousExtensions) 2411 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 2412 << E->getSourceRange(); 2413 else 2414 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 2415 << E->getSourceRange(); 2416 // Accept, even if we emitted an error diagnostic. 2417 return false; 2418 } 2419 2420 // None of the above, just randomly invalid non-lvalue. 2421 return true; 2422} 2423 2424/// isOperandMentioned - Return true if the specified operand # is mentioned 2425/// anywhere in the decomposed asm string. 2426static bool isOperandMentioned(unsigned OpNo, 2427 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2428 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2429 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2430 if (!Piece.isOperand()) continue; 2431 2432 // If this is a reference to the input and if the input was the smaller 2433 // one, then we have to reject this asm. 2434 if (Piece.getOperandNo() == OpNo) 2435 return true; 2436 } 2437 2438 return false; 2439} 2440 2441StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2442 bool IsVolatile, unsigned NumOutputs, 2443 unsigned NumInputs, IdentifierInfo **Names, 2444 MultiExprArg constraints, MultiExprArg exprs, 2445 Expr *asmString, MultiExprArg clobbers, 2446 SourceLocation RParenLoc, bool MSAsm) { 2447 unsigned NumClobbers = clobbers.size(); 2448 StringLiteral **Constraints = 2449 reinterpret_cast<StringLiteral**>(constraints.get()); 2450 Expr **Exprs = exprs.get(); 2451 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2452 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2453 2454 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2455 2456 // The parser verifies that there is a string literal here. 2457 if (!AsmString->isAscii()) 2458 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2459 << AsmString->getSourceRange()); 2460 2461 for (unsigned i = 0; i != NumOutputs; i++) { 2462 StringLiteral *Literal = Constraints[i]; 2463 if (!Literal->isAscii()) 2464 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2465 << Literal->getSourceRange()); 2466 2467 StringRef OutputName; 2468 if (Names[i]) 2469 OutputName = Names[i]->getName(); 2470 2471 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2472 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2473 return StmtError(Diag(Literal->getLocStart(), 2474 diag::err_asm_invalid_output_constraint) 2475 << Info.getConstraintStr()); 2476 2477 // Check that the output exprs are valid lvalues. 2478 Expr *OutputExpr = Exprs[i]; 2479 if (CheckAsmLValue(OutputExpr, *this)) { 2480 return StmtError(Diag(OutputExpr->getLocStart(), 2481 diag::err_asm_invalid_lvalue_in_output) 2482 << OutputExpr->getSourceRange()); 2483 } 2484 2485 OutputConstraintInfos.push_back(Info); 2486 } 2487 2488 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2489 2490 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2491 StringLiteral *Literal = Constraints[i]; 2492 if (!Literal->isAscii()) 2493 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2494 << Literal->getSourceRange()); 2495 2496 StringRef InputName; 2497 if (Names[i]) 2498 InputName = Names[i]->getName(); 2499 2500 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2501 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2502 NumOutputs, Info)) { 2503 return StmtError(Diag(Literal->getLocStart(), 2504 diag::err_asm_invalid_input_constraint) 2505 << Info.getConstraintStr()); 2506 } 2507 2508 Expr *InputExpr = Exprs[i]; 2509 2510 // Only allow void types for memory constraints. 2511 if (Info.allowsMemory() && !Info.allowsRegister()) { 2512 if (CheckAsmLValue(InputExpr, *this)) 2513 return StmtError(Diag(InputExpr->getLocStart(), 2514 diag::err_asm_invalid_lvalue_in_input) 2515 << Info.getConstraintStr() 2516 << InputExpr->getSourceRange()); 2517 } 2518 2519 if (Info.allowsRegister()) { 2520 if (InputExpr->getType()->isVoidType()) { 2521 return StmtError(Diag(InputExpr->getLocStart(), 2522 diag::err_asm_invalid_type_in_input) 2523 << InputExpr->getType() << Info.getConstraintStr() 2524 << InputExpr->getSourceRange()); 2525 } 2526 } 2527 2528 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2529 if (Result.isInvalid()) 2530 return StmtError(); 2531 2532 Exprs[i] = Result.take(); 2533 InputConstraintInfos.push_back(Info); 2534 } 2535 2536 // Check that the clobbers are valid. 2537 for (unsigned i = 0; i != NumClobbers; i++) { 2538 StringLiteral *Literal = Clobbers[i]; 2539 if (!Literal->isAscii()) 2540 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2541 << Literal->getSourceRange()); 2542 2543 StringRef Clobber = Literal->getString(); 2544 2545 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2546 return StmtError(Diag(Literal->getLocStart(), 2547 diag::err_asm_unknown_register_name) << Clobber); 2548 } 2549 2550 AsmStmt *NS = 2551 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2552 NumOutputs, NumInputs, Names, Constraints, Exprs, 2553 AsmString, NumClobbers, Clobbers, RParenLoc); 2554 // Validate the asm string, ensuring it makes sense given the operands we 2555 // have. 2556 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2557 unsigned DiagOffs; 2558 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2559 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2560 << AsmString->getSourceRange(); 2561 return StmtError(); 2562 } 2563 2564 // Validate tied input operands for type mismatches. 2565 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2566 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2567 2568 // If this is a tied constraint, verify that the output and input have 2569 // either exactly the same type, or that they are int/ptr operands with the 2570 // same size (int/long, int*/long, are ok etc). 2571 if (!Info.hasTiedOperand()) continue; 2572 2573 unsigned TiedTo = Info.getTiedOperand(); 2574 unsigned InputOpNo = i+NumOutputs; 2575 Expr *OutputExpr = Exprs[TiedTo]; 2576 Expr *InputExpr = Exprs[InputOpNo]; 2577 2578 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2579 continue; 2580 2581 QualType InTy = InputExpr->getType(); 2582 QualType OutTy = OutputExpr->getType(); 2583 if (Context.hasSameType(InTy, OutTy)) 2584 continue; // All types can be tied to themselves. 2585 2586 // Decide if the input and output are in the same domain (integer/ptr or 2587 // floating point. 2588 enum AsmDomain { 2589 AD_Int, AD_FP, AD_Other 2590 } InputDomain, OutputDomain; 2591 2592 if (InTy->isIntegerType() || InTy->isPointerType()) 2593 InputDomain = AD_Int; 2594 else if (InTy->isRealFloatingType()) 2595 InputDomain = AD_FP; 2596 else 2597 InputDomain = AD_Other; 2598 2599 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2600 OutputDomain = AD_Int; 2601 else if (OutTy->isRealFloatingType()) 2602 OutputDomain = AD_FP; 2603 else 2604 OutputDomain = AD_Other; 2605 2606 // They are ok if they are the same size and in the same domain. This 2607 // allows tying things like: 2608 // void* to int* 2609 // void* to int if they are the same size. 2610 // double to long double if they are the same size. 2611 // 2612 uint64_t OutSize = Context.getTypeSize(OutTy); 2613 uint64_t InSize = Context.getTypeSize(InTy); 2614 if (OutSize == InSize && InputDomain == OutputDomain && 2615 InputDomain != AD_Other) 2616 continue; 2617 2618 // If the smaller input/output operand is not mentioned in the asm string, 2619 // then we can promote the smaller one to a larger input and the asm string 2620 // won't notice. 2621 bool SmallerValueMentioned = false; 2622 2623 // If this is a reference to the input and if the input was the smaller 2624 // one, then we have to reject this asm. 2625 if (isOperandMentioned(InputOpNo, Pieces)) { 2626 // This is a use in the asm string of the smaller operand. Since we 2627 // codegen this by promoting to a wider value, the asm will get printed 2628 // "wrong". 2629 SmallerValueMentioned |= InSize < OutSize; 2630 } 2631 if (isOperandMentioned(TiedTo, Pieces)) { 2632 // If this is a reference to the output, and if the output is the larger 2633 // value, then it's ok because we'll promote the input to the larger type. 2634 SmallerValueMentioned |= OutSize < InSize; 2635 } 2636 2637 // If the smaller value wasn't mentioned in the asm string, and if the 2638 // output was a register, just extend the shorter one to the size of the 2639 // larger one. 2640 if (!SmallerValueMentioned && InputDomain != AD_Other && 2641 OutputConstraintInfos[TiedTo].allowsRegister()) 2642 continue; 2643 2644 // Either both of the operands were mentioned or the smaller one was 2645 // mentioned. One more special case that we'll allow: if the tied input is 2646 // integer, unmentioned, and is a constant, then we'll allow truncating it 2647 // down to the size of the destination. 2648 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2649 !isOperandMentioned(InputOpNo, Pieces) && 2650 InputExpr->isEvaluatable(Context)) { 2651 CastKind castKind = 2652 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2653 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2654 Exprs[InputOpNo] = InputExpr; 2655 NS->setInputExpr(i, InputExpr); 2656 continue; 2657 } 2658 2659 Diag(InputExpr->getLocStart(), 2660 diag::err_asm_tying_incompatible_types) 2661 << InTy << OutTy << OutputExpr->getSourceRange() 2662 << InputExpr->getSourceRange(); 2663 return StmtError(); 2664 } 2665 2666 return Owned(NS); 2667} 2668 2669StmtResult 2670Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2671 SourceLocation RParen, Decl *Parm, 2672 Stmt *Body) { 2673 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2674 if (Var && Var->isInvalidDecl()) 2675 return StmtError(); 2676 2677 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2678} 2679 2680StmtResult 2681Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2682 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2683} 2684 2685StmtResult 2686Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2687 MultiStmtArg CatchStmts, Stmt *Finally) { 2688 if (!getLangOpts().ObjCExceptions) 2689 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2690 2691 getCurFunction()->setHasBranchProtectedScope(); 2692 unsigned NumCatchStmts = CatchStmts.size(); 2693 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2694 CatchStmts.release(), 2695 NumCatchStmts, 2696 Finally)); 2697} 2698 2699StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) { 2700 if (Throw) { 2701 ExprResult Result = DefaultLvalueConversion(Throw); 2702 if (Result.isInvalid()) 2703 return StmtError(); 2704 2705 Throw = MaybeCreateExprWithCleanups(Result.take()); 2706 QualType ThrowType = Throw->getType(); 2707 // Make sure the expression type is an ObjC pointer or "void *". 2708 if (!ThrowType->isDependentType() && 2709 !ThrowType->isObjCObjectPointerType()) { 2710 const PointerType *PT = ThrowType->getAs<PointerType>(); 2711 if (!PT || !PT->getPointeeType()->isVoidType()) 2712 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2713 << Throw->getType() << Throw->getSourceRange()); 2714 } 2715 } 2716 2717 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2718} 2719 2720StmtResult 2721Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2722 Scope *CurScope) { 2723 if (!getLangOpts().ObjCExceptions) 2724 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2725 2726 if (!Throw) { 2727 // @throw without an expression designates a rethrow (which much occur 2728 // in the context of an @catch clause). 2729 Scope *AtCatchParent = CurScope; 2730 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2731 AtCatchParent = AtCatchParent->getParent(); 2732 if (!AtCatchParent) 2733 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2734 } 2735 2736 return BuildObjCAtThrowStmt(AtLoc, Throw); 2737} 2738 2739ExprResult 2740Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 2741 ExprResult result = DefaultLvalueConversion(operand); 2742 if (result.isInvalid()) 2743 return ExprError(); 2744 operand = result.take(); 2745 2746 // Make sure the expression type is an ObjC pointer or "void *". 2747 QualType type = operand->getType(); 2748 if (!type->isDependentType() && 2749 !type->isObjCObjectPointerType()) { 2750 const PointerType *pointerType = type->getAs<PointerType>(); 2751 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 2752 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 2753 << type << operand->getSourceRange(); 2754 } 2755 2756 // The operand to @synchronized is a full-expression. 2757 return MaybeCreateExprWithCleanups(operand); 2758} 2759 2760StmtResult 2761Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2762 Stmt *SyncBody) { 2763 // We can't jump into or indirect-jump out of a @synchronized block. 2764 getCurFunction()->setHasBranchProtectedScope(); 2765 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2766} 2767 2768/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2769/// and creates a proper catch handler from them. 2770StmtResult 2771Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2772 Stmt *HandlerBlock) { 2773 // There's nothing to test that ActOnExceptionDecl didn't already test. 2774 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2775 cast_or_null<VarDecl>(ExDecl), 2776 HandlerBlock)); 2777} 2778 2779StmtResult 2780Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2781 getCurFunction()->setHasBranchProtectedScope(); 2782 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2783} 2784 2785namespace { 2786 2787class TypeWithHandler { 2788 QualType t; 2789 CXXCatchStmt *stmt; 2790public: 2791 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2792 : t(type), stmt(statement) {} 2793 2794 // An arbitrary order is fine as long as it places identical 2795 // types next to each other. 2796 bool operator<(const TypeWithHandler &y) const { 2797 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2798 return true; 2799 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2800 return false; 2801 else 2802 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2803 } 2804 2805 bool operator==(const TypeWithHandler& other) const { 2806 return t == other.t; 2807 } 2808 2809 CXXCatchStmt *getCatchStmt() const { return stmt; } 2810 SourceLocation getTypeSpecStartLoc() const { 2811 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2812 } 2813}; 2814 2815} 2816 2817/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2818/// handlers and creates a try statement from them. 2819StmtResult 2820Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2821 MultiStmtArg RawHandlers) { 2822 // Don't report an error if 'try' is used in system headers. 2823 if (!getLangOpts().CXXExceptions && 2824 !getSourceManager().isInSystemHeader(TryLoc)) 2825 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2826 2827 unsigned NumHandlers = RawHandlers.size(); 2828 assert(NumHandlers > 0 && 2829 "The parser shouldn't call this if there are no handlers."); 2830 Stmt **Handlers = RawHandlers.get(); 2831 2832 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2833 2834 for (unsigned i = 0; i < NumHandlers; ++i) { 2835 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2836 if (!Handler->getExceptionDecl()) { 2837 if (i < NumHandlers - 1) 2838 return StmtError(Diag(Handler->getLocStart(), 2839 diag::err_early_catch_all)); 2840 2841 continue; 2842 } 2843 2844 const QualType CaughtType = Handler->getCaughtType(); 2845 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2846 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2847 } 2848 2849 // Detect handlers for the same type as an earlier one. 2850 if (NumHandlers > 1) { 2851 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2852 2853 TypeWithHandler prev = TypesWithHandlers[0]; 2854 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2855 TypeWithHandler curr = TypesWithHandlers[i]; 2856 2857 if (curr == prev) { 2858 Diag(curr.getTypeSpecStartLoc(), 2859 diag::warn_exception_caught_by_earlier_handler) 2860 << curr.getCatchStmt()->getCaughtType().getAsString(); 2861 Diag(prev.getTypeSpecStartLoc(), 2862 diag::note_previous_exception_handler) 2863 << prev.getCatchStmt()->getCaughtType().getAsString(); 2864 } 2865 2866 prev = curr; 2867 } 2868 } 2869 2870 getCurFunction()->setHasBranchProtectedScope(); 2871 2872 // FIXME: We should detect handlers that cannot catch anything because an 2873 // earlier handler catches a superclass. Need to find a method that is not 2874 // quadratic for this. 2875 // Neither of these are explicitly forbidden, but every compiler detects them 2876 // and warns. 2877 2878 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2879 Handlers, NumHandlers)); 2880} 2881 2882StmtResult 2883Sema::ActOnSEHTryBlock(bool IsCXXTry, 2884 SourceLocation TryLoc, 2885 Stmt *TryBlock, 2886 Stmt *Handler) { 2887 assert(TryBlock && Handler); 2888 2889 getCurFunction()->setHasBranchProtectedScope(); 2890 2891 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2892} 2893 2894StmtResult 2895Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2896 Expr *FilterExpr, 2897 Stmt *Block) { 2898 assert(FilterExpr && Block); 2899 2900 if(!FilterExpr->getType()->isIntegerType()) { 2901 return StmtError(Diag(FilterExpr->getExprLoc(), 2902 diag::err_filter_expression_integral) 2903 << FilterExpr->getType()); 2904 } 2905 2906 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2907} 2908 2909StmtResult 2910Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2911 Stmt *Block) { 2912 assert(Block); 2913 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2914} 2915 2916StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 2917 bool IsIfExists, 2918 NestedNameSpecifierLoc QualifierLoc, 2919 DeclarationNameInfo NameInfo, 2920 Stmt *Nested) 2921{ 2922 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 2923 QualifierLoc, NameInfo, 2924 cast<CompoundStmt>(Nested)); 2925} 2926 2927 2928StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 2929 bool IsIfExists, 2930 CXXScopeSpec &SS, 2931 UnqualifiedId &Name, 2932 Stmt *Nested) { 2933 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 2934 SS.getWithLocInContext(Context), 2935 GetNameFromUnqualifiedId(Name), 2936 Nested); 2937} 2938