SemaStmt.cpp revision 8cd64b4c5553fa6284d248336cb7c82dc960a394
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/SmallString.h" 34#include "llvm/ADT/SmallVector.h" 35using namespace clang; 36using namespace sema; 37 38StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 39 Expr *E = expr.get(); 40 if (!E) // FIXME: FullExprArg has no error state? 41 return StmtError(); 42 43 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 44 // void expression for its side effects. Conversion to void allows any 45 // operand, even incomplete types. 46 47 // Same thing in for stmt first clause (when expr) and third clause. 48 return Owned(static_cast<Stmt*>(E)); 49} 50 51 52StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, 53 bool HasLeadingEmptyMacro) { 54 return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro)); 55} 56 57StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 58 SourceLocation EndLoc) { 59 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 60 61 // If we have an invalid decl, just return an error. 62 if (DG.isNull()) return StmtError(); 63 64 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 65} 66 67void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 68 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 69 70 // If we have an invalid decl, just return. 71 if (DG.isNull() || !DG.isSingleDecl()) return; 72 VarDecl *var = cast<VarDecl>(DG.getSingleDecl()); 73 74 // suppress any potential 'unused variable' warning. 75 var->setUsed(); 76 77 // foreach variables are never actually initialized in the way that 78 // the parser came up with. 79 var->setInit(0); 80 81 // In ARC, we don't need to retain the iteration variable of a fast 82 // enumeration loop. Rather than actually trying to catch that 83 // during declaration processing, we remove the consequences here. 84 if (getLangOpts().ObjCAutoRefCount) { 85 QualType type = var->getType(); 86 87 // Only do this if we inferred the lifetime. Inferred lifetime 88 // will show up as a local qualifier because explicit lifetime 89 // should have shown up as an AttributedType instead. 90 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { 91 // Add 'const' and mark the variable as pseudo-strong. 92 var->setType(type.withConst()); 93 var->setARCPseudoStrong(true); 94 } 95 } 96} 97 98/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='. 99/// 100/// Adding a cast to void (or other expression wrappers) will prevent the 101/// warning from firing. 102static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) { 103 SourceLocation Loc; 104 bool IsNotEqual, CanAssign; 105 106 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) { 107 if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE) 108 return false; 109 110 Loc = Op->getOperatorLoc(); 111 IsNotEqual = Op->getOpcode() == BO_NE; 112 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue(); 113 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) { 114 if (Op->getOperator() != OO_EqualEqual && 115 Op->getOperator() != OO_ExclaimEqual) 116 return false; 117 118 Loc = Op->getOperatorLoc(); 119 IsNotEqual = Op->getOperator() == OO_ExclaimEqual; 120 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue(); 121 } else { 122 // Not a typo-prone comparison. 123 return false; 124 } 125 126 // Suppress warnings when the operator, suspicious as it may be, comes from 127 // a macro expansion. 128 if (Loc.isMacroID()) 129 return false; 130 131 S.Diag(Loc, diag::warn_unused_comparison) 132 << (unsigned)IsNotEqual << E->getSourceRange(); 133 134 // If the LHS is a plausible entity to assign to, provide a fixit hint to 135 // correct common typos. 136 if (CanAssign) { 137 if (IsNotEqual) 138 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign) 139 << FixItHint::CreateReplacement(Loc, "|="); 140 else 141 S.Diag(Loc, diag::note_equality_comparison_to_assign) 142 << FixItHint::CreateReplacement(Loc, "="); 143 } 144 145 return true; 146} 147 148void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 149 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 150 return DiagnoseUnusedExprResult(Label->getSubStmt()); 151 152 const Expr *E = dyn_cast_or_null<Expr>(S); 153 if (!E) 154 return; 155 156 const Expr *WarnExpr; 157 SourceLocation Loc; 158 SourceRange R1, R2; 159 if (SourceMgr.isInSystemMacro(E->getExprLoc()) || 160 !E->isUnusedResultAWarning(WarnExpr, Loc, R1, R2, Context)) 161 return; 162 163 // Okay, we have an unused result. Depending on what the base expression is, 164 // we might want to make a more specific diagnostic. Check for one of these 165 // cases now. 166 unsigned DiagID = diag::warn_unused_expr; 167 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 168 E = Temps->getSubExpr(); 169 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 170 E = TempExpr->getSubExpr(); 171 172 if (DiagnoseUnusedComparison(*this, E)) 173 return; 174 175 E = WarnExpr; 176 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 177 if (E->getType()->isVoidType()) 178 return; 179 180 // If the callee has attribute pure, const, or warn_unused_result, warn with 181 // a more specific message to make it clear what is happening. 182 if (const Decl *FD = CE->getCalleeDecl()) { 183 if (FD->getAttr<WarnUnusedResultAttr>()) { 184 Diag(Loc, diag::warn_unused_result) << R1 << R2; 185 return; 186 } 187 if (FD->getAttr<PureAttr>()) { 188 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 189 return; 190 } 191 if (FD->getAttr<ConstAttr>()) { 192 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 193 return; 194 } 195 } 196 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 197 if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) { 198 Diag(Loc, diag::err_arc_unused_init_message) << R1; 199 return; 200 } 201 const ObjCMethodDecl *MD = ME->getMethodDecl(); 202 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 203 Diag(Loc, diag::warn_unused_result) << R1 << R2; 204 return; 205 } 206 } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) { 207 const Expr *Source = POE->getSyntacticForm(); 208 if (isa<ObjCSubscriptRefExpr>(Source)) 209 DiagID = diag::warn_unused_container_subscript_expr; 210 else 211 DiagID = diag::warn_unused_property_expr; 212 } else if (const CXXFunctionalCastExpr *FC 213 = dyn_cast<CXXFunctionalCastExpr>(E)) { 214 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 215 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 216 return; 217 } 218 // Diagnose "(void*) blah" as a typo for "(void) blah". 219 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 220 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 221 QualType T = TI->getType(); 222 223 // We really do want to use the non-canonical type here. 224 if (T == Context.VoidPtrTy) { 225 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 226 227 Diag(Loc, diag::warn_unused_voidptr) 228 << FixItHint::CreateRemoval(TL.getStarLoc()); 229 return; 230 } 231 } 232 233 if (E->isGLValue() && E->getType().isVolatileQualified()) { 234 Diag(Loc, diag::warn_unused_volatile) << R1 << R2; 235 return; 236 } 237 238 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 239} 240 241void Sema::ActOnStartOfCompoundStmt() { 242 PushCompoundScope(); 243} 244 245void Sema::ActOnFinishOfCompoundStmt() { 246 PopCompoundScope(); 247} 248 249sema::CompoundScopeInfo &Sema::getCurCompoundScope() const { 250 return getCurFunction()->CompoundScopes.back(); 251} 252 253StmtResult 254Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 255 MultiStmtArg elts, bool isStmtExpr) { 256 unsigned NumElts = elts.size(); 257 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 258 // If we're in C89 mode, check that we don't have any decls after stmts. If 259 // so, emit an extension diagnostic. 260 if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) { 261 // Note that __extension__ can be around a decl. 262 unsigned i = 0; 263 // Skip over all declarations. 264 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 265 /*empty*/; 266 267 // We found the end of the list or a statement. Scan for another declstmt. 268 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 269 /*empty*/; 270 271 if (i != NumElts) { 272 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 273 Diag(D->getLocation(), diag::ext_mixed_decls_code); 274 } 275 } 276 // Warn about unused expressions in statements. 277 for (unsigned i = 0; i != NumElts; ++i) { 278 // Ignore statements that are last in a statement expression. 279 if (isStmtExpr && i == NumElts - 1) 280 continue; 281 282 DiagnoseUnusedExprResult(Elts[i]); 283 } 284 285 // Check for suspicious empty body (null statement) in `for' and `while' 286 // statements. Don't do anything for template instantiations, this just adds 287 // noise. 288 if (NumElts != 0 && !CurrentInstantiationScope && 289 getCurCompoundScope().HasEmptyLoopBodies) { 290 for (unsigned i = 0; i != NumElts - 1; ++i) 291 DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]); 292 } 293 294 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 295} 296 297StmtResult 298Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 299 SourceLocation DotDotDotLoc, Expr *RHSVal, 300 SourceLocation ColonLoc) { 301 assert((LHSVal != 0) && "missing expression in case statement"); 302 303 if (getCurFunction()->SwitchStack.empty()) { 304 Diag(CaseLoc, diag::err_case_not_in_switch); 305 return StmtError(); 306 } 307 308 if (!getLangOpts().CPlusPlus0x) { 309 // C99 6.8.4.2p3: The expression shall be an integer constant. 310 // However, GCC allows any evaluatable integer expression. 311 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) { 312 LHSVal = VerifyIntegerConstantExpression(LHSVal).take(); 313 if (!LHSVal) 314 return StmtError(); 315 } 316 317 // GCC extension: The expression shall be an integer constant. 318 319 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) { 320 RHSVal = VerifyIntegerConstantExpression(RHSVal).take(); 321 // Recover from an error by just forgetting about it. 322 } 323 } 324 325 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 326 ColonLoc); 327 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 328 return Owned(CS); 329} 330 331/// ActOnCaseStmtBody - This installs a statement as the body of a case. 332void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 333 DiagnoseUnusedExprResult(SubStmt); 334 335 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 336 CS->setSubStmt(SubStmt); 337} 338 339StmtResult 340Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 341 Stmt *SubStmt, Scope *CurScope) { 342 DiagnoseUnusedExprResult(SubStmt); 343 344 if (getCurFunction()->SwitchStack.empty()) { 345 Diag(DefaultLoc, diag::err_default_not_in_switch); 346 return Owned(SubStmt); 347 } 348 349 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 350 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 351 return Owned(DS); 352} 353 354StmtResult 355Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 356 SourceLocation ColonLoc, Stmt *SubStmt) { 357 // If the label was multiply defined, reject it now. 358 if (TheDecl->getStmt()) { 359 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 360 Diag(TheDecl->getLocation(), diag::note_previous_definition); 361 return Owned(SubStmt); 362 } 363 364 // Otherwise, things are good. Fill in the declaration and return it. 365 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 366 TheDecl->setStmt(LS); 367 if (!TheDecl->isGnuLocal()) 368 TheDecl->setLocation(IdentLoc); 369 return Owned(LS); 370} 371 372StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc, 373 const AttrVec &Attrs, 374 Stmt *SubStmt) { 375 // Fill in the declaration and return it. Variable length will require to 376 // change this to AttributedStmt::Create(Context, ....); 377 // and probably using ArrayRef 378 AttributedStmt *LS = new (Context) AttributedStmt(AttrLoc, Attrs, SubStmt); 379 return Owned(LS); 380} 381 382StmtResult 383Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 384 Stmt *thenStmt, SourceLocation ElseLoc, 385 Stmt *elseStmt) { 386 ExprResult CondResult(CondVal.release()); 387 388 VarDecl *ConditionVar = 0; 389 if (CondVar) { 390 ConditionVar = cast<VarDecl>(CondVar); 391 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 392 if (CondResult.isInvalid()) 393 return StmtError(); 394 } 395 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 396 if (!ConditionExpr) 397 return StmtError(); 398 399 DiagnoseUnusedExprResult(thenStmt); 400 401 if (!elseStmt) { 402 DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt, 403 diag::warn_empty_if_body); 404 } 405 406 DiagnoseUnusedExprResult(elseStmt); 407 408 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 409 thenStmt, ElseLoc, elseStmt)); 410} 411 412/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 413/// the specified width and sign. If an overflow occurs, detect it and emit 414/// the specified diagnostic. 415void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 416 unsigned NewWidth, bool NewSign, 417 SourceLocation Loc, 418 unsigned DiagID) { 419 // Perform a conversion to the promoted condition type if needed. 420 if (NewWidth > Val.getBitWidth()) { 421 // If this is an extension, just do it. 422 Val = Val.extend(NewWidth); 423 Val.setIsSigned(NewSign); 424 425 // If the input was signed and negative and the output is 426 // unsigned, don't bother to warn: this is implementation-defined 427 // behavior. 428 // FIXME: Introduce a second, default-ignored warning for this case? 429 } else if (NewWidth < Val.getBitWidth()) { 430 // If this is a truncation, check for overflow. 431 llvm::APSInt ConvVal(Val); 432 ConvVal = ConvVal.trunc(NewWidth); 433 ConvVal.setIsSigned(NewSign); 434 ConvVal = ConvVal.extend(Val.getBitWidth()); 435 ConvVal.setIsSigned(Val.isSigned()); 436 if (ConvVal != Val) 437 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 438 439 // Regardless of whether a diagnostic was emitted, really do the 440 // truncation. 441 Val = Val.trunc(NewWidth); 442 Val.setIsSigned(NewSign); 443 } else if (NewSign != Val.isSigned()) { 444 // Convert the sign to match the sign of the condition. This can cause 445 // overflow as well: unsigned(INTMIN) 446 // We don't diagnose this overflow, because it is implementation-defined 447 // behavior. 448 // FIXME: Introduce a second, default-ignored warning for this case? 449 llvm::APSInt OldVal(Val); 450 Val.setIsSigned(NewSign); 451 } 452} 453 454namespace { 455 struct CaseCompareFunctor { 456 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 457 const llvm::APSInt &RHS) { 458 return LHS.first < RHS; 459 } 460 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 461 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 462 return LHS.first < RHS.first; 463 } 464 bool operator()(const llvm::APSInt &LHS, 465 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 466 return LHS < RHS.first; 467 } 468 }; 469} 470 471/// CmpCaseVals - Comparison predicate for sorting case values. 472/// 473static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 474 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 475 if (lhs.first < rhs.first) 476 return true; 477 478 if (lhs.first == rhs.first && 479 lhs.second->getCaseLoc().getRawEncoding() 480 < rhs.second->getCaseLoc().getRawEncoding()) 481 return true; 482 return false; 483} 484 485/// CmpEnumVals - Comparison predicate for sorting enumeration values. 486/// 487static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 488 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 489{ 490 return lhs.first < rhs.first; 491} 492 493/// EqEnumVals - Comparison preficate for uniqing enumeration values. 494/// 495static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 496 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 497{ 498 return lhs.first == rhs.first; 499} 500 501/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 502/// potentially integral-promoted expression @p expr. 503static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 504 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 505 expr = cleanups->getSubExpr(); 506 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 507 if (impcast->getCastKind() != CK_IntegralCast) break; 508 expr = impcast->getSubExpr(); 509 } 510 return expr->getType(); 511} 512 513StmtResult 514Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 515 Decl *CondVar) { 516 ExprResult CondResult; 517 518 VarDecl *ConditionVar = 0; 519 if (CondVar) { 520 ConditionVar = cast<VarDecl>(CondVar); 521 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 522 if (CondResult.isInvalid()) 523 return StmtError(); 524 525 Cond = CondResult.release(); 526 } 527 528 if (!Cond) 529 return StmtError(); 530 531 class SwitchConvertDiagnoser : public ICEConvertDiagnoser { 532 Expr *Cond; 533 534 public: 535 SwitchConvertDiagnoser(Expr *Cond) 536 : ICEConvertDiagnoser(false, true), Cond(Cond) { } 537 538 virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc, 539 QualType T) { 540 return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T; 541 } 542 543 virtual DiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc, 544 QualType T) { 545 return S.Diag(Loc, diag::err_switch_incomplete_class_type) 546 << T << Cond->getSourceRange(); 547 } 548 549 virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc, 550 QualType T, 551 QualType ConvTy) { 552 return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy; 553 } 554 555 virtual DiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv, 556 QualType ConvTy) { 557 return S.Diag(Conv->getLocation(), diag::note_switch_conversion) 558 << ConvTy->isEnumeralType() << ConvTy; 559 } 560 561 virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc, 562 QualType T) { 563 return S.Diag(Loc, diag::err_switch_multiple_conversions) << T; 564 } 565 566 virtual DiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv, 567 QualType ConvTy) { 568 return S.Diag(Conv->getLocation(), diag::note_switch_conversion) 569 << ConvTy->isEnumeralType() << ConvTy; 570 } 571 572 virtual DiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc, 573 QualType T, 574 QualType ConvTy) { 575 return DiagnosticBuilder::getEmpty(); 576 } 577 } SwitchDiagnoser(Cond); 578 579 CondResult 580 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, SwitchDiagnoser, 581 /*AllowScopedEnumerations*/ true); 582 if (CondResult.isInvalid()) return StmtError(); 583 Cond = CondResult.take(); 584 585 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 586 CondResult = UsualUnaryConversions(Cond); 587 if (CondResult.isInvalid()) return StmtError(); 588 Cond = CondResult.take(); 589 590 if (!CondVar) { 591 CheckImplicitConversions(Cond, SwitchLoc); 592 CondResult = MaybeCreateExprWithCleanups(Cond); 593 if (CondResult.isInvalid()) 594 return StmtError(); 595 Cond = CondResult.take(); 596 } 597 598 getCurFunction()->setHasBranchIntoScope(); 599 600 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 601 getCurFunction()->SwitchStack.push_back(SS); 602 return Owned(SS); 603} 604 605static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 606 if (Val.getBitWidth() < BitWidth) 607 Val = Val.extend(BitWidth); 608 else if (Val.getBitWidth() > BitWidth) 609 Val = Val.trunc(BitWidth); 610 Val.setIsSigned(IsSigned); 611} 612 613StmtResult 614Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 615 Stmt *BodyStmt) { 616 SwitchStmt *SS = cast<SwitchStmt>(Switch); 617 assert(SS == getCurFunction()->SwitchStack.back() && 618 "switch stack missing push/pop!"); 619 620 SS->setBody(BodyStmt, SwitchLoc); 621 getCurFunction()->SwitchStack.pop_back(); 622 623 Expr *CondExpr = SS->getCond(); 624 if (!CondExpr) return StmtError(); 625 626 QualType CondType = CondExpr->getType(); 627 628 Expr *CondExprBeforePromotion = CondExpr; 629 QualType CondTypeBeforePromotion = 630 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 631 632 // C++ 6.4.2.p2: 633 // Integral promotions are performed (on the switch condition). 634 // 635 // A case value unrepresentable by the original switch condition 636 // type (before the promotion) doesn't make sense, even when it can 637 // be represented by the promoted type. Therefore we need to find 638 // the pre-promotion type of the switch condition. 639 if (!CondExpr->isTypeDependent()) { 640 // We have already converted the expression to an integral or enumeration 641 // type, when we started the switch statement. If we don't have an 642 // appropriate type now, just return an error. 643 if (!CondType->isIntegralOrEnumerationType()) 644 return StmtError(); 645 646 if (CondExpr->isKnownToHaveBooleanValue()) { 647 // switch(bool_expr) {...} is often a programmer error, e.g. 648 // switch(n && mask) { ... } // Doh - should be "n & mask". 649 // One can always use an if statement instead of switch(bool_expr). 650 Diag(SwitchLoc, diag::warn_bool_switch_condition) 651 << CondExpr->getSourceRange(); 652 } 653 } 654 655 // Get the bitwidth of the switched-on value before promotions. We must 656 // convert the integer case values to this width before comparison. 657 bool HasDependentValue 658 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 659 unsigned CondWidth 660 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 661 bool CondIsSigned 662 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 663 664 // Accumulate all of the case values in a vector so that we can sort them 665 // and detect duplicates. This vector contains the APInt for the case after 666 // it has been converted to the condition type. 667 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 668 CaseValsTy CaseVals; 669 670 // Keep track of any GNU case ranges we see. The APSInt is the low value. 671 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 672 CaseRangesTy CaseRanges; 673 674 DefaultStmt *TheDefaultStmt = 0; 675 676 bool CaseListIsErroneous = false; 677 678 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 679 SC = SC->getNextSwitchCase()) { 680 681 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 682 if (TheDefaultStmt) { 683 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 684 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 685 686 // FIXME: Remove the default statement from the switch block so that 687 // we'll return a valid AST. This requires recursing down the AST and 688 // finding it, not something we are set up to do right now. For now, 689 // just lop the entire switch stmt out of the AST. 690 CaseListIsErroneous = true; 691 } 692 TheDefaultStmt = DS; 693 694 } else { 695 CaseStmt *CS = cast<CaseStmt>(SC); 696 697 Expr *Lo = CS->getLHS(); 698 699 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 700 HasDependentValue = true; 701 break; 702 } 703 704 llvm::APSInt LoVal; 705 706 if (getLangOpts().CPlusPlus0x) { 707 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 708 // constant expression of the promoted type of the switch condition. 709 ExprResult ConvLo = 710 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue); 711 if (ConvLo.isInvalid()) { 712 CaseListIsErroneous = true; 713 continue; 714 } 715 Lo = ConvLo.take(); 716 } else { 717 // We already verified that the expression has a i-c-e value (C99 718 // 6.8.4.2p3) - get that value now. 719 LoVal = Lo->EvaluateKnownConstInt(Context); 720 721 // If the LHS is not the same type as the condition, insert an implicit 722 // cast. 723 Lo = DefaultLvalueConversion(Lo).take(); 724 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 725 } 726 727 // Convert the value to the same width/sign as the condition had prior to 728 // integral promotions. 729 // 730 // FIXME: This causes us to reject valid code: 731 // switch ((char)c) { case 256: case 0: return 0; } 732 // Here we claim there is a duplicated condition value, but there is not. 733 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 734 Lo->getLocStart(), 735 diag::warn_case_value_overflow); 736 737 CS->setLHS(Lo); 738 739 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 740 if (CS->getRHS()) { 741 if (CS->getRHS()->isTypeDependent() || 742 CS->getRHS()->isValueDependent()) { 743 HasDependentValue = true; 744 break; 745 } 746 CaseRanges.push_back(std::make_pair(LoVal, CS)); 747 } else 748 CaseVals.push_back(std::make_pair(LoVal, CS)); 749 } 750 } 751 752 if (!HasDependentValue) { 753 // If we don't have a default statement, check whether the 754 // condition is constant. 755 llvm::APSInt ConstantCondValue; 756 bool HasConstantCond = false; 757 if (!HasDependentValue && !TheDefaultStmt) { 758 HasConstantCond 759 = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context, 760 Expr::SE_AllowSideEffects); 761 assert(!HasConstantCond || 762 (ConstantCondValue.getBitWidth() == CondWidth && 763 ConstantCondValue.isSigned() == CondIsSigned)); 764 } 765 bool ShouldCheckConstantCond = HasConstantCond; 766 767 // Sort all the scalar case values so we can easily detect duplicates. 768 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 769 770 if (!CaseVals.empty()) { 771 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 772 if (ShouldCheckConstantCond && 773 CaseVals[i].first == ConstantCondValue) 774 ShouldCheckConstantCond = false; 775 776 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 777 // If we have a duplicate, report it. 778 // First, determine if either case value has a name 779 StringRef PrevString, CurrString; 780 Expr *PrevCase = CaseVals[i-1].second->getLHS()->IgnoreParenCasts(); 781 Expr *CurrCase = CaseVals[i].second->getLHS()->IgnoreParenCasts(); 782 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(PrevCase)) { 783 PrevString = DeclRef->getDecl()->getName(); 784 } 785 if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(CurrCase)) { 786 CurrString = DeclRef->getDecl()->getName(); 787 } 788 llvm::SmallString<16> CaseValStr; 789 CaseVals[i-1].first.toString(CaseValStr); 790 791 if (PrevString == CurrString) 792 Diag(CaseVals[i].second->getLHS()->getLocStart(), 793 diag::err_duplicate_case) << 794 (PrevString.empty() ? CaseValStr.str() : PrevString); 795 else 796 Diag(CaseVals[i].second->getLHS()->getLocStart(), 797 diag::err_duplicate_case_differing_expr) << 798 (PrevString.empty() ? CaseValStr.str() : PrevString) << 799 (CurrString.empty() ? CaseValStr.str() : CurrString) << 800 CaseValStr; 801 802 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 803 diag::note_duplicate_case_prev); 804 // FIXME: We really want to remove the bogus case stmt from the 805 // substmt, but we have no way to do this right now. 806 CaseListIsErroneous = true; 807 } 808 } 809 } 810 811 // Detect duplicate case ranges, which usually don't exist at all in 812 // the first place. 813 if (!CaseRanges.empty()) { 814 // Sort all the case ranges by their low value so we can easily detect 815 // overlaps between ranges. 816 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 817 818 // Scan the ranges, computing the high values and removing empty ranges. 819 std::vector<llvm::APSInt> HiVals; 820 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 821 llvm::APSInt &LoVal = CaseRanges[i].first; 822 CaseStmt *CR = CaseRanges[i].second; 823 Expr *Hi = CR->getRHS(); 824 llvm::APSInt HiVal; 825 826 if (getLangOpts().CPlusPlus0x) { 827 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 828 // constant expression of the promoted type of the switch condition. 829 ExprResult ConvHi = 830 CheckConvertedConstantExpression(Hi, CondType, HiVal, 831 CCEK_CaseValue); 832 if (ConvHi.isInvalid()) { 833 CaseListIsErroneous = true; 834 continue; 835 } 836 Hi = ConvHi.take(); 837 } else { 838 HiVal = Hi->EvaluateKnownConstInt(Context); 839 840 // If the RHS is not the same type as the condition, insert an 841 // implicit cast. 842 Hi = DefaultLvalueConversion(Hi).take(); 843 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 844 } 845 846 // Convert the value to the same width/sign as the condition. 847 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 848 Hi->getLocStart(), 849 diag::warn_case_value_overflow); 850 851 CR->setRHS(Hi); 852 853 // If the low value is bigger than the high value, the case is empty. 854 if (LoVal > HiVal) { 855 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 856 << SourceRange(CR->getLHS()->getLocStart(), 857 Hi->getLocEnd()); 858 CaseRanges.erase(CaseRanges.begin()+i); 859 --i, --e; 860 continue; 861 } 862 863 if (ShouldCheckConstantCond && 864 LoVal <= ConstantCondValue && 865 ConstantCondValue <= HiVal) 866 ShouldCheckConstantCond = false; 867 868 HiVals.push_back(HiVal); 869 } 870 871 // Rescan the ranges, looking for overlap with singleton values and other 872 // ranges. Since the range list is sorted, we only need to compare case 873 // ranges with their neighbors. 874 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 875 llvm::APSInt &CRLo = CaseRanges[i].first; 876 llvm::APSInt &CRHi = HiVals[i]; 877 CaseStmt *CR = CaseRanges[i].second; 878 879 // Check to see whether the case range overlaps with any 880 // singleton cases. 881 CaseStmt *OverlapStmt = 0; 882 llvm::APSInt OverlapVal(32); 883 884 // Find the smallest value >= the lower bound. If I is in the 885 // case range, then we have overlap. 886 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 887 CaseVals.end(), CRLo, 888 CaseCompareFunctor()); 889 if (I != CaseVals.end() && I->first < CRHi) { 890 OverlapVal = I->first; // Found overlap with scalar. 891 OverlapStmt = I->second; 892 } 893 894 // Find the smallest value bigger than the upper bound. 895 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 896 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 897 OverlapVal = (I-1)->first; // Found overlap with scalar. 898 OverlapStmt = (I-1)->second; 899 } 900 901 // Check to see if this case stmt overlaps with the subsequent 902 // case range. 903 if (i && CRLo <= HiVals[i-1]) { 904 OverlapVal = HiVals[i-1]; // Found overlap with range. 905 OverlapStmt = CaseRanges[i-1].second; 906 } 907 908 if (OverlapStmt) { 909 // If we have a duplicate, report it. 910 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 911 << OverlapVal.toString(10); 912 Diag(OverlapStmt->getLHS()->getLocStart(), 913 diag::note_duplicate_case_prev); 914 // FIXME: We really want to remove the bogus case stmt from the 915 // substmt, but we have no way to do this right now. 916 CaseListIsErroneous = true; 917 } 918 } 919 } 920 921 // Complain if we have a constant condition and we didn't find a match. 922 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 923 // TODO: it would be nice if we printed enums as enums, chars as 924 // chars, etc. 925 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 926 << ConstantCondValue.toString(10) 927 << CondExpr->getSourceRange(); 928 } 929 930 // Check to see if switch is over an Enum and handles all of its 931 // values. We only issue a warning if there is not 'default:', but 932 // we still do the analysis to preserve this information in the AST 933 // (which can be used by flow-based analyes). 934 // 935 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 936 937 // If switch has default case, then ignore it. 938 if (!CaseListIsErroneous && !HasConstantCond && ET) { 939 const EnumDecl *ED = ET->getDecl(); 940 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 941 EnumValsTy; 942 EnumValsTy EnumVals; 943 944 // Gather all enum values, set their type and sort them, 945 // allowing easier comparison with CaseVals. 946 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 947 EDI != ED->enumerator_end(); ++EDI) { 948 llvm::APSInt Val = EDI->getInitVal(); 949 AdjustAPSInt(Val, CondWidth, CondIsSigned); 950 EnumVals.push_back(std::make_pair(Val, *EDI)); 951 } 952 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 953 EnumValsTy::iterator EIend = 954 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 955 956 // See which case values aren't in enum. 957 EnumValsTy::const_iterator EI = EnumVals.begin(); 958 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 959 CI != CaseVals.end(); CI++) { 960 while (EI != EIend && EI->first < CI->first) 961 EI++; 962 if (EI == EIend || EI->first > CI->first) 963 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 964 << CondTypeBeforePromotion; 965 } 966 // See which of case ranges aren't in enum 967 EI = EnumVals.begin(); 968 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 969 RI != CaseRanges.end() && EI != EIend; RI++) { 970 while (EI != EIend && EI->first < RI->first) 971 EI++; 972 973 if (EI == EIend || EI->first != RI->first) { 974 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 975 << CondTypeBeforePromotion; 976 } 977 978 llvm::APSInt Hi = 979 RI->second->getRHS()->EvaluateKnownConstInt(Context); 980 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 981 while (EI != EIend && EI->first < Hi) 982 EI++; 983 if (EI == EIend || EI->first != Hi) 984 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 985 << CondTypeBeforePromotion; 986 } 987 988 // Check which enum vals aren't in switch 989 CaseValsTy::const_iterator CI = CaseVals.begin(); 990 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 991 bool hasCasesNotInSwitch = false; 992 993 SmallVector<DeclarationName,8> UnhandledNames; 994 995 for (EI = EnumVals.begin(); EI != EIend; EI++){ 996 // Drop unneeded case values 997 llvm::APSInt CIVal; 998 while (CI != CaseVals.end() && CI->first < EI->first) 999 CI++; 1000 1001 if (CI != CaseVals.end() && CI->first == EI->first) 1002 continue; 1003 1004 // Drop unneeded case ranges 1005 for (; RI != CaseRanges.end(); RI++) { 1006 llvm::APSInt Hi = 1007 RI->second->getRHS()->EvaluateKnownConstInt(Context); 1008 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 1009 if (EI->first <= Hi) 1010 break; 1011 } 1012 1013 if (RI == CaseRanges.end() || EI->first < RI->first) { 1014 hasCasesNotInSwitch = true; 1015 UnhandledNames.push_back(EI->second->getDeclName()); 1016 } 1017 } 1018 1019 if (TheDefaultStmt && UnhandledNames.empty()) 1020 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default); 1021 1022 // Produce a nice diagnostic if multiple values aren't handled. 1023 switch (UnhandledNames.size()) { 1024 case 0: break; 1025 case 1: 1026 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1027 ? diag::warn_def_missing_case1 : diag::warn_missing_case1) 1028 << UnhandledNames[0]; 1029 break; 1030 case 2: 1031 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1032 ? diag::warn_def_missing_case2 : diag::warn_missing_case2) 1033 << UnhandledNames[0] << UnhandledNames[1]; 1034 break; 1035 case 3: 1036 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1037 ? diag::warn_def_missing_case3 : diag::warn_missing_case3) 1038 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 1039 break; 1040 default: 1041 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1042 ? diag::warn_def_missing_cases : diag::warn_missing_cases) 1043 << (unsigned)UnhandledNames.size() 1044 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 1045 break; 1046 } 1047 1048 if (!hasCasesNotInSwitch) 1049 SS->setAllEnumCasesCovered(); 1050 } 1051 } 1052 1053 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt, 1054 diag::warn_empty_switch_body); 1055 1056 // FIXME: If the case list was broken is some way, we don't have a good system 1057 // to patch it up. Instead, just return the whole substmt as broken. 1058 if (CaseListIsErroneous) 1059 return StmtError(); 1060 1061 return Owned(SS); 1062} 1063 1064StmtResult 1065Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 1066 Decl *CondVar, Stmt *Body) { 1067 ExprResult CondResult(Cond.release()); 1068 1069 VarDecl *ConditionVar = 0; 1070 if (CondVar) { 1071 ConditionVar = cast<VarDecl>(CondVar); 1072 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 1073 if (CondResult.isInvalid()) 1074 return StmtError(); 1075 } 1076 Expr *ConditionExpr = CondResult.take(); 1077 if (!ConditionExpr) 1078 return StmtError(); 1079 1080 DiagnoseUnusedExprResult(Body); 1081 1082 if (isa<NullStmt>(Body)) 1083 getCurCompoundScope().setHasEmptyLoopBodies(); 1084 1085 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 1086 Body, WhileLoc)); 1087} 1088 1089StmtResult 1090Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 1091 SourceLocation WhileLoc, SourceLocation CondLParen, 1092 Expr *Cond, SourceLocation CondRParen) { 1093 assert(Cond && "ActOnDoStmt(): missing expression"); 1094 1095 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 1096 if (CondResult.isInvalid() || CondResult.isInvalid()) 1097 return StmtError(); 1098 Cond = CondResult.take(); 1099 1100 CheckImplicitConversions(Cond, DoLoc); 1101 CondResult = MaybeCreateExprWithCleanups(Cond); 1102 if (CondResult.isInvalid()) 1103 return StmtError(); 1104 Cond = CondResult.take(); 1105 1106 DiagnoseUnusedExprResult(Body); 1107 1108 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 1109} 1110 1111namespace { 1112 // This visitor will traverse a conditional statement and store all 1113 // the evaluated decls into a vector. Simple is set to true if none 1114 // of the excluded constructs are used. 1115 class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> { 1116 llvm::SmallPtrSet<VarDecl*, 8> &Decls; 1117 llvm::SmallVector<SourceRange, 10> &Ranges; 1118 bool Simple; 1119public: 1120 typedef EvaluatedExprVisitor<DeclExtractor> Inherited; 1121 1122 DeclExtractor(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, 1123 llvm::SmallVector<SourceRange, 10> &Ranges) : 1124 Inherited(S.Context), 1125 Decls(Decls), 1126 Ranges(Ranges), 1127 Simple(true) {} 1128 1129 bool isSimple() { return Simple; } 1130 1131 // Replaces the method in EvaluatedExprVisitor. 1132 void VisitMemberExpr(MemberExpr* E) { 1133 Simple = false; 1134 } 1135 1136 // Any Stmt not whitelisted will cause the condition to be marked complex. 1137 void VisitStmt(Stmt *S) { 1138 Simple = false; 1139 } 1140 1141 void VisitBinaryOperator(BinaryOperator *E) { 1142 Visit(E->getLHS()); 1143 Visit(E->getRHS()); 1144 } 1145 1146 void VisitCastExpr(CastExpr *E) { 1147 Visit(E->getSubExpr()); 1148 } 1149 1150 void VisitUnaryOperator(UnaryOperator *E) { 1151 // Skip checking conditionals with derefernces. 1152 if (E->getOpcode() == UO_Deref) 1153 Simple = false; 1154 else 1155 Visit(E->getSubExpr()); 1156 } 1157 1158 void VisitConditionalOperator(ConditionalOperator *E) { 1159 Visit(E->getCond()); 1160 Visit(E->getTrueExpr()); 1161 Visit(E->getFalseExpr()); 1162 } 1163 1164 void VisitParenExpr(ParenExpr *E) { 1165 Visit(E->getSubExpr()); 1166 } 1167 1168 void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) { 1169 Visit(E->getOpaqueValue()->getSourceExpr()); 1170 Visit(E->getFalseExpr()); 1171 } 1172 1173 void VisitIntegerLiteral(IntegerLiteral *E) { } 1174 void VisitFloatingLiteral(FloatingLiteral *E) { } 1175 void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { } 1176 void VisitCharacterLiteral(CharacterLiteral *E) { } 1177 void VisitGNUNullExpr(GNUNullExpr *E) { } 1178 void VisitImaginaryLiteral(ImaginaryLiteral *E) { } 1179 1180 void VisitDeclRefExpr(DeclRefExpr *E) { 1181 VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()); 1182 if (!VD) return; 1183 1184 Ranges.push_back(E->getSourceRange()); 1185 1186 Decls.insert(VD); 1187 } 1188 1189 }; // end class DeclExtractor 1190 1191 // DeclMatcher checks to see if the decls are used in a non-evauluated 1192 // context. 1193 class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> { 1194 llvm::SmallPtrSet<VarDecl*, 8> &Decls; 1195 bool FoundDecl; 1196 1197public: 1198 typedef EvaluatedExprVisitor<DeclMatcher> Inherited; 1199 1200 DeclMatcher(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, Stmt *Statement) : 1201 Inherited(S.Context), Decls(Decls), FoundDecl(false) { 1202 if (!Statement) return; 1203 1204 Visit(Statement); 1205 } 1206 1207 void VisitReturnStmt(ReturnStmt *S) { 1208 FoundDecl = true; 1209 } 1210 1211 void VisitBreakStmt(BreakStmt *S) { 1212 FoundDecl = true; 1213 } 1214 1215 void VisitGotoStmt(GotoStmt *S) { 1216 FoundDecl = true; 1217 } 1218 1219 void VisitCastExpr(CastExpr *E) { 1220 if (E->getCastKind() == CK_LValueToRValue) 1221 CheckLValueToRValueCast(E->getSubExpr()); 1222 else 1223 Visit(E->getSubExpr()); 1224 } 1225 1226 void CheckLValueToRValueCast(Expr *E) { 1227 E = E->IgnoreParenImpCasts(); 1228 1229 if (isa<DeclRefExpr>(E)) { 1230 return; 1231 } 1232 1233 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 1234 Visit(CO->getCond()); 1235 CheckLValueToRValueCast(CO->getTrueExpr()); 1236 CheckLValueToRValueCast(CO->getFalseExpr()); 1237 return; 1238 } 1239 1240 if (BinaryConditionalOperator *BCO = 1241 dyn_cast<BinaryConditionalOperator>(E)) { 1242 CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr()); 1243 CheckLValueToRValueCast(BCO->getFalseExpr()); 1244 return; 1245 } 1246 1247 Visit(E); 1248 } 1249 1250 void VisitDeclRefExpr(DeclRefExpr *E) { 1251 if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl())) 1252 if (Decls.count(VD)) 1253 FoundDecl = true; 1254 } 1255 1256 bool FoundDeclInUse() { return FoundDecl; } 1257 1258 }; // end class DeclMatcher 1259 1260 void CheckForLoopConditionalStatement(Sema &S, Expr *Second, 1261 Expr *Third, Stmt *Body) { 1262 // Condition is empty 1263 if (!Second) return; 1264 1265 if (S.Diags.getDiagnosticLevel(diag::warn_variables_not_in_loop_body, 1266 Second->getLocStart()) 1267 == DiagnosticsEngine::Ignored) 1268 return; 1269 1270 PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body); 1271 llvm::SmallPtrSet<VarDecl*, 8> Decls; 1272 llvm::SmallVector<SourceRange, 10> Ranges; 1273 DeclExtractor DE(S, Decls, Ranges); 1274 DE.Visit(Second); 1275 1276 // Don't analyze complex conditionals. 1277 if (!DE.isSimple()) return; 1278 1279 // No decls found. 1280 if (Decls.size() == 0) return; 1281 1282 // Don't warn on volatile, static, or global variables. 1283 for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(), 1284 E = Decls.end(); 1285 I != E; ++I) 1286 if ((*I)->getType().isVolatileQualified() || 1287 (*I)->hasGlobalStorage()) return; 1288 1289 if (DeclMatcher(S, Decls, Second).FoundDeclInUse() || 1290 DeclMatcher(S, Decls, Third).FoundDeclInUse() || 1291 DeclMatcher(S, Decls, Body).FoundDeclInUse()) 1292 return; 1293 1294 // Load decl names into diagnostic. 1295 if (Decls.size() > 4) 1296 PDiag << 0; 1297 else { 1298 PDiag << Decls.size(); 1299 for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(), 1300 E = Decls.end(); 1301 I != E; ++I) 1302 PDiag << (*I)->getDeclName(); 1303 } 1304 1305 // Load SourceRanges into diagnostic if there is room. 1306 // Otherwise, load the SourceRange of the conditional expression. 1307 if (Ranges.size() <= PartialDiagnostic::MaxArguments) 1308 for (llvm::SmallVector<SourceRange, 10>::iterator I = Ranges.begin(), 1309 E = Ranges.end(); 1310 I != E; ++I) 1311 PDiag << *I; 1312 else 1313 PDiag << Second->getSourceRange(); 1314 1315 S.Diag(Ranges.begin()->getBegin(), PDiag); 1316 } 1317 1318} // end namespace 1319 1320StmtResult 1321Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1322 Stmt *First, FullExprArg second, Decl *secondVar, 1323 FullExprArg third, 1324 SourceLocation RParenLoc, Stmt *Body) { 1325 if (!getLangOpts().CPlusPlus) { 1326 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 1327 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1328 // declare identifiers for objects having storage class 'auto' or 1329 // 'register'. 1330 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 1331 DI!=DE; ++DI) { 1332 VarDecl *VD = dyn_cast<VarDecl>(*DI); 1333 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 1334 VD = 0; 1335 if (VD == 0) 1336 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 1337 // FIXME: mark decl erroneous! 1338 } 1339 } 1340 } 1341 1342 CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body); 1343 1344 ExprResult SecondResult(second.release()); 1345 VarDecl *ConditionVar = 0; 1346 if (secondVar) { 1347 ConditionVar = cast<VarDecl>(secondVar); 1348 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1349 if (SecondResult.isInvalid()) 1350 return StmtError(); 1351 } 1352 1353 Expr *Third = third.release().takeAs<Expr>(); 1354 1355 DiagnoseUnusedExprResult(First); 1356 DiagnoseUnusedExprResult(Third); 1357 DiagnoseUnusedExprResult(Body); 1358 1359 if (isa<NullStmt>(Body)) 1360 getCurCompoundScope().setHasEmptyLoopBodies(); 1361 1362 return Owned(new (Context) ForStmt(Context, First, 1363 SecondResult.take(), ConditionVar, 1364 Third, Body, ForLoc, LParenLoc, 1365 RParenLoc)); 1366} 1367 1368/// In an Objective C collection iteration statement: 1369/// for (x in y) 1370/// x can be an arbitrary l-value expression. Bind it up as a 1371/// full-expression. 1372StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1373 // Reduce placeholder expressions here. Note that this rejects the 1374 // use of pseudo-object l-values in this position. 1375 ExprResult result = CheckPlaceholderExpr(E); 1376 if (result.isInvalid()) return StmtError(); 1377 E = result.take(); 1378 1379 CheckImplicitConversions(E); 1380 1381 result = MaybeCreateExprWithCleanups(E); 1382 if (result.isInvalid()) return StmtError(); 1383 1384 return Owned(static_cast<Stmt*>(result.take())); 1385} 1386 1387ExprResult 1388Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1389 assert(collection); 1390 1391 // Bail out early if we've got a type-dependent expression. 1392 if (collection->isTypeDependent()) return Owned(collection); 1393 1394 // Perform normal l-value conversion. 1395 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1396 if (result.isInvalid()) 1397 return ExprError(); 1398 collection = result.take(); 1399 1400 // The operand needs to have object-pointer type. 1401 // TODO: should we do a contextual conversion? 1402 const ObjCObjectPointerType *pointerType = 1403 collection->getType()->getAs<ObjCObjectPointerType>(); 1404 if (!pointerType) 1405 return Diag(forLoc, diag::err_collection_expr_type) 1406 << collection->getType() << collection->getSourceRange(); 1407 1408 // Check that the operand provides 1409 // - countByEnumeratingWithState:objects:count: 1410 const ObjCObjectType *objectType = pointerType->getObjectType(); 1411 ObjCInterfaceDecl *iface = objectType->getInterface(); 1412 1413 // If we have a forward-declared type, we can't do this check. 1414 // Under ARC, it is an error not to have a forward-declared class. 1415 if (iface && 1416 RequireCompleteType(forLoc, QualType(objectType, 0), 1417 getLangOpts().ObjCAutoRefCount 1418 ? diag::err_arc_collection_forward 1419 : 0, 1420 collection)) { 1421 // Otherwise, if we have any useful type information, check that 1422 // the type declares the appropriate method. 1423 } else if (iface || !objectType->qual_empty()) { 1424 IdentifierInfo *selectorIdents[] = { 1425 &Context.Idents.get("countByEnumeratingWithState"), 1426 &Context.Idents.get("objects"), 1427 &Context.Idents.get("count") 1428 }; 1429 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1430 1431 ObjCMethodDecl *method = 0; 1432 1433 // If there's an interface, look in both the public and private APIs. 1434 if (iface) { 1435 method = iface->lookupInstanceMethod(selector); 1436 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1437 } 1438 1439 // Also check protocol qualifiers. 1440 if (!method) 1441 method = LookupMethodInQualifiedType(selector, pointerType, 1442 /*instance*/ true); 1443 1444 // If we didn't find it anywhere, give up. 1445 if (!method) { 1446 Diag(forLoc, diag::warn_collection_expr_type) 1447 << collection->getType() << selector << collection->getSourceRange(); 1448 } 1449 1450 // TODO: check for an incompatible signature? 1451 } 1452 1453 // Wrap up any cleanups in the expression. 1454 return Owned(MaybeCreateExprWithCleanups(collection)); 1455} 1456 1457StmtResult 1458Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1459 SourceLocation LParenLoc, 1460 Stmt *First, Expr *Second, 1461 SourceLocation RParenLoc, Stmt *Body) { 1462 if (First) { 1463 QualType FirstType; 1464 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1465 if (!DS->isSingleDecl()) 1466 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1467 diag::err_toomany_element_decls)); 1468 1469 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1470 FirstType = D->getType(); 1471 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1472 // declare identifiers for objects having storage class 'auto' or 1473 // 'register'. 1474 if (!D->hasLocalStorage()) 1475 return StmtError(Diag(D->getLocation(), 1476 diag::err_non_variable_decl_in_for)); 1477 } else { 1478 Expr *FirstE = cast<Expr>(First); 1479 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1480 return StmtError(Diag(First->getLocStart(), 1481 diag::err_selector_element_not_lvalue) 1482 << First->getSourceRange()); 1483 1484 FirstType = static_cast<Expr*>(First)->getType(); 1485 } 1486 if (!FirstType->isDependentType() && 1487 !FirstType->isObjCObjectPointerType() && 1488 !FirstType->isBlockPointerType()) 1489 Diag(ForLoc, diag::err_selector_element_type) 1490 << FirstType << First->getSourceRange(); 1491 } 1492 1493 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1494 ForLoc, RParenLoc)); 1495} 1496 1497namespace { 1498 1499enum BeginEndFunction { 1500 BEF_begin, 1501 BEF_end 1502}; 1503 1504/// Build a variable declaration for a for-range statement. 1505static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1506 QualType Type, const char *Name) { 1507 DeclContext *DC = SemaRef.CurContext; 1508 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1509 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1510 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1511 TInfo, SC_Auto, SC_None); 1512 Decl->setImplicit(); 1513 return Decl; 1514} 1515 1516/// Finish building a variable declaration for a for-range statement. 1517/// \return true if an error occurs. 1518static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1519 SourceLocation Loc, int diag) { 1520 // Deduce the type for the iterator variable now rather than leaving it to 1521 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1522 TypeSourceInfo *InitTSI = 0; 1523 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) || 1524 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) == 1525 Sema::DAR_Failed) 1526 SemaRef.Diag(Loc, diag) << Init->getType(); 1527 if (!InitTSI) { 1528 Decl->setInvalidDecl(); 1529 return true; 1530 } 1531 Decl->setTypeSourceInfo(InitTSI); 1532 Decl->setType(InitTSI->getType()); 1533 1534 // In ARC, infer lifetime. 1535 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1536 // we're doing the equivalent of fast iteration. 1537 if (SemaRef.getLangOpts().ObjCAutoRefCount && 1538 SemaRef.inferObjCARCLifetime(Decl)) 1539 Decl->setInvalidDecl(); 1540 1541 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1542 /*TypeMayContainAuto=*/false); 1543 SemaRef.FinalizeDeclaration(Decl); 1544 SemaRef.CurContext->addHiddenDecl(Decl); 1545 return false; 1546} 1547 1548/// Produce a note indicating which begin/end function was implicitly called 1549/// by a C++0x for-range statement. This is often not obvious from the code, 1550/// nor from the diagnostics produced when analysing the implicit expressions 1551/// required in a for-range statement. 1552void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1553 BeginEndFunction BEF) { 1554 CallExpr *CE = dyn_cast<CallExpr>(E); 1555 if (!CE) 1556 return; 1557 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1558 if (!D) 1559 return; 1560 SourceLocation Loc = D->getLocation(); 1561 1562 std::string Description; 1563 bool IsTemplate = false; 1564 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1565 Description = SemaRef.getTemplateArgumentBindingsText( 1566 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1567 IsTemplate = true; 1568 } 1569 1570 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1571 << BEF << IsTemplate << Description << E->getType(); 1572} 1573 1574/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1575/// given LookupResult is non-empty, it is assumed to describe a member which 1576/// will be invoked. Otherwise, the function will be found via argument 1577/// dependent lookup. 1578static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1579 SourceLocation Loc, 1580 VarDecl *Decl, 1581 BeginEndFunction BEF, 1582 const DeclarationNameInfo &NameInfo, 1583 LookupResult &MemberLookup, 1584 Expr *Range) { 1585 ExprResult CallExpr; 1586 if (!MemberLookup.empty()) { 1587 ExprResult MemberRef = 1588 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1589 /*IsPtr=*/false, CXXScopeSpec(), 1590 /*TemplateKWLoc=*/SourceLocation(), 1591 /*FirstQualifierInScope=*/0, 1592 MemberLookup, 1593 /*TemplateArgs=*/0); 1594 if (MemberRef.isInvalid()) 1595 return ExprError(); 1596 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1597 Loc, 0); 1598 if (CallExpr.isInvalid()) 1599 return ExprError(); 1600 } else { 1601 UnresolvedSet<0> FoundNames; 1602 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1603 // std is an associated namespace. 1604 UnresolvedLookupExpr *Fn = 1605 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1606 NestedNameSpecifierLoc(), NameInfo, 1607 /*NeedsADL=*/true, /*Overloaded=*/false, 1608 FoundNames.begin(), FoundNames.end(), 1609 /*LookInStdNamespace=*/true); 1610 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1611 0, /*AllowTypoCorrection=*/false); 1612 if (CallExpr.isInvalid()) { 1613 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1614 << Range->getType(); 1615 return ExprError(); 1616 } 1617 } 1618 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1619 diag::err_for_range_iter_deduction_failure)) { 1620 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1621 return ExprError(); 1622 } 1623 return CallExpr; 1624} 1625 1626} 1627 1628/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1629/// 1630/// C++0x [stmt.ranged]: 1631/// A range-based for statement is equivalent to 1632/// 1633/// { 1634/// auto && __range = range-init; 1635/// for ( auto __begin = begin-expr, 1636/// __end = end-expr; 1637/// __begin != __end; 1638/// ++__begin ) { 1639/// for-range-declaration = *__begin; 1640/// statement 1641/// } 1642/// } 1643/// 1644/// The body of the loop is not available yet, since it cannot be analysed until 1645/// we have determined the type of the for-range-declaration. 1646StmtResult 1647Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1648 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1649 SourceLocation RParenLoc) { 1650 if (!First || !Range) 1651 return StmtError(); 1652 1653 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1654 assert(DS && "first part of for range not a decl stmt"); 1655 1656 if (!DS->isSingleDecl()) { 1657 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1658 return StmtError(); 1659 } 1660 if (DS->getSingleDecl()->isInvalidDecl()) 1661 return StmtError(); 1662 1663 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1664 return StmtError(); 1665 1666 // Build auto && __range = range-init 1667 SourceLocation RangeLoc = Range->getLocStart(); 1668 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1669 Context.getAutoRRefDeductType(), 1670 "__range"); 1671 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1672 diag::err_for_range_deduction_failure)) 1673 return StmtError(); 1674 1675 // Claim the type doesn't contain auto: we've already done the checking. 1676 DeclGroupPtrTy RangeGroup = 1677 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1678 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1679 if (RangeDecl.isInvalid()) 1680 return StmtError(); 1681 1682 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1683 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1684 RParenLoc); 1685} 1686 1687/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1688StmtResult 1689Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1690 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1691 Expr *Inc, Stmt *LoopVarDecl, 1692 SourceLocation RParenLoc) { 1693 Scope *S = getCurScope(); 1694 1695 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1696 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1697 QualType RangeVarType = RangeVar->getType(); 1698 1699 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1700 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1701 1702 StmtResult BeginEndDecl = BeginEnd; 1703 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1704 1705 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1706 SourceLocation RangeLoc = RangeVar->getLocation(); 1707 1708 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1709 1710 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1711 VK_LValue, ColonLoc); 1712 if (BeginRangeRef.isInvalid()) 1713 return StmtError(); 1714 1715 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1716 VK_LValue, ColonLoc); 1717 if (EndRangeRef.isInvalid()) 1718 return StmtError(); 1719 1720 QualType AutoType = Context.getAutoDeductType(); 1721 Expr *Range = RangeVar->getInit(); 1722 if (!Range) 1723 return StmtError(); 1724 QualType RangeType = Range->getType(); 1725 1726 if (RequireCompleteType(RangeLoc, RangeType, 1727 diag::err_for_range_incomplete_type)) 1728 return StmtError(); 1729 1730 // Build auto __begin = begin-expr, __end = end-expr. 1731 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1732 "__begin"); 1733 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1734 "__end"); 1735 1736 // Build begin-expr and end-expr and attach to __begin and __end variables. 1737 ExprResult BeginExpr, EndExpr; 1738 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1739 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1740 // __range + __bound, respectively, where __bound is the array bound. If 1741 // _RangeT is an array of unknown size or an array of incomplete type, 1742 // the program is ill-formed; 1743 1744 // begin-expr is __range. 1745 BeginExpr = BeginRangeRef; 1746 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1747 diag::err_for_range_iter_deduction_failure)) { 1748 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1749 return StmtError(); 1750 } 1751 1752 // Find the array bound. 1753 ExprResult BoundExpr; 1754 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1755 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1756 Context.getPointerDiffType(), 1757 RangeLoc)); 1758 else if (const VariableArrayType *VAT = 1759 dyn_cast<VariableArrayType>(UnqAT)) 1760 BoundExpr = VAT->getSizeExpr(); 1761 else { 1762 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1763 // UnqAT is not incomplete and Range is not type-dependent. 1764 llvm_unreachable("Unexpected array type in for-range"); 1765 } 1766 1767 // end-expr is __range + __bound. 1768 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1769 BoundExpr.get()); 1770 if (EndExpr.isInvalid()) 1771 return StmtError(); 1772 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1773 diag::err_for_range_iter_deduction_failure)) { 1774 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1775 return StmtError(); 1776 } 1777 } else { 1778 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1779 ColonLoc); 1780 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1781 ColonLoc); 1782 1783 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1784 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1785 1786 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1787 // - if _RangeT is a class type, the unqualified-ids begin and end are 1788 // looked up in the scope of class _RangeT as if by class member access 1789 // lookup (3.4.5), and if either (or both) finds at least one 1790 // declaration, begin-expr and end-expr are __range.begin() and 1791 // __range.end(), respectively; 1792 LookupQualifiedName(BeginMemberLookup, D); 1793 LookupQualifiedName(EndMemberLookup, D); 1794 1795 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1796 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1797 << RangeType << BeginMemberLookup.empty(); 1798 return StmtError(); 1799 } 1800 } else { 1801 // - otherwise, begin-expr and end-expr are begin(__range) and 1802 // end(__range), respectively, where begin and end are looked up with 1803 // argument-dependent lookup (3.4.2). For the purposes of this name 1804 // lookup, namespace std is an associated namespace. 1805 } 1806 1807 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1808 BEF_begin, BeginNameInfo, 1809 BeginMemberLookup, 1810 BeginRangeRef.get()); 1811 if (BeginExpr.isInvalid()) 1812 return StmtError(); 1813 1814 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1815 BEF_end, EndNameInfo, 1816 EndMemberLookup, EndRangeRef.get()); 1817 if (EndExpr.isInvalid()) 1818 return StmtError(); 1819 } 1820 1821 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1822 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1823 if (!Context.hasSameType(BeginType, EndType)) { 1824 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1825 << BeginType << EndType; 1826 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1827 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1828 } 1829 1830 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1831 // Claim the type doesn't contain auto: we've already done the checking. 1832 DeclGroupPtrTy BeginEndGroup = 1833 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1834 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1835 1836 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1837 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1838 VK_LValue, ColonLoc); 1839 if (BeginRef.isInvalid()) 1840 return StmtError(); 1841 1842 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1843 VK_LValue, ColonLoc); 1844 if (EndRef.isInvalid()) 1845 return StmtError(); 1846 1847 // Build and check __begin != __end expression. 1848 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1849 BeginRef.get(), EndRef.get()); 1850 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1851 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1852 if (NotEqExpr.isInvalid()) { 1853 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1854 if (!Context.hasSameType(BeginType, EndType)) 1855 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1856 return StmtError(); 1857 } 1858 1859 // Build and check ++__begin expression. 1860 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1861 VK_LValue, ColonLoc); 1862 if (BeginRef.isInvalid()) 1863 return StmtError(); 1864 1865 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1866 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1867 if (IncrExpr.isInvalid()) { 1868 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1869 return StmtError(); 1870 } 1871 1872 // Build and check *__begin expression. 1873 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1874 VK_LValue, ColonLoc); 1875 if (BeginRef.isInvalid()) 1876 return StmtError(); 1877 1878 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1879 if (DerefExpr.isInvalid()) { 1880 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1881 return StmtError(); 1882 } 1883 1884 // Attach *__begin as initializer for VD. 1885 if (!LoopVar->isInvalidDecl()) { 1886 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1887 /*TypeMayContainAuto=*/true); 1888 if (LoopVar->isInvalidDecl()) 1889 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1890 } 1891 } else { 1892 // The range is implicitly used as a placeholder when it is dependent. 1893 RangeVar->setUsed(); 1894 } 1895 1896 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1897 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1898 NotEqExpr.take(), IncrExpr.take(), 1899 LoopVarDS, /*Body=*/0, ForLoc, 1900 ColonLoc, RParenLoc)); 1901} 1902 1903/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1904/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1905/// body cannot be performed until after the type of the range variable is 1906/// determined. 1907StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1908 if (!S || !B) 1909 return StmtError(); 1910 1911 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S); 1912 ForStmt->setBody(B); 1913 1914 DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B, 1915 diag::warn_empty_range_based_for_body); 1916 1917 return S; 1918} 1919 1920StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1921 SourceLocation LabelLoc, 1922 LabelDecl *TheDecl) { 1923 getCurFunction()->setHasBranchIntoScope(); 1924 TheDecl->setUsed(); 1925 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1926} 1927 1928StmtResult 1929Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1930 Expr *E) { 1931 // Convert operand to void* 1932 if (!E->isTypeDependent()) { 1933 QualType ETy = E->getType(); 1934 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1935 ExprResult ExprRes = Owned(E); 1936 AssignConvertType ConvTy = 1937 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1938 if (ExprRes.isInvalid()) 1939 return StmtError(); 1940 E = ExprRes.take(); 1941 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1942 return StmtError(); 1943 E = MaybeCreateExprWithCleanups(E); 1944 } 1945 1946 getCurFunction()->setHasIndirectGoto(); 1947 1948 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1949} 1950 1951StmtResult 1952Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1953 Scope *S = CurScope->getContinueParent(); 1954 if (!S) { 1955 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1956 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1957 } 1958 1959 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1960} 1961 1962StmtResult 1963Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1964 Scope *S = CurScope->getBreakParent(); 1965 if (!S) { 1966 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1967 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1968 } 1969 1970 return Owned(new (Context) BreakStmt(BreakLoc)); 1971} 1972 1973/// \brief Determine whether the given expression is a candidate for 1974/// copy elision in either a return statement or a throw expression. 1975/// 1976/// \param ReturnType If we're determining the copy elision candidate for 1977/// a return statement, this is the return type of the function. If we're 1978/// determining the copy elision candidate for a throw expression, this will 1979/// be a NULL type. 1980/// 1981/// \param E The expression being returned from the function or block, or 1982/// being thrown. 1983/// 1984/// \param AllowFunctionParameter Whether we allow function parameters to 1985/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1986/// we re-use this logic to determine whether we should try to move as part of 1987/// a return or throw (which does allow function parameters). 1988/// 1989/// \returns The NRVO candidate variable, if the return statement may use the 1990/// NRVO, or NULL if there is no such candidate. 1991const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1992 Expr *E, 1993 bool AllowFunctionParameter) { 1994 QualType ExprType = E->getType(); 1995 // - in a return statement in a function with ... 1996 // ... a class return type ... 1997 if (!ReturnType.isNull()) { 1998 if (!ReturnType->isRecordType()) 1999 return 0; 2000 // ... the same cv-unqualified type as the function return type ... 2001 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 2002 return 0; 2003 } 2004 2005 // ... the expression is the name of a non-volatile automatic object 2006 // (other than a function or catch-clause parameter)) ... 2007 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 2008 if (!DR) 2009 return 0; 2010 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 2011 if (!VD) 2012 return 0; 2013 2014 // ...object (other than a function or catch-clause parameter)... 2015 if (VD->getKind() != Decl::Var && 2016 !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) 2017 return 0; 2018 if (VD->isExceptionVariable()) return 0; 2019 2020 // ...automatic... 2021 if (!VD->hasLocalStorage()) return 0; 2022 2023 // ...non-volatile... 2024 if (VD->getType().isVolatileQualified()) return 0; 2025 if (VD->getType()->isReferenceType()) return 0; 2026 2027 // __block variables can't be allocated in a way that permits NRVO. 2028 if (VD->hasAttr<BlocksAttr>()) return 0; 2029 2030 // Variables with higher required alignment than their type's ABI 2031 // alignment cannot use NRVO. 2032 if (VD->hasAttr<AlignedAttr>() && 2033 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) 2034 return 0; 2035 2036 return VD; 2037} 2038 2039/// \brief Perform the initialization of a potentially-movable value, which 2040/// is the result of return value. 2041/// 2042/// This routine implements C++0x [class.copy]p33, which attempts to treat 2043/// returned lvalues as rvalues in certain cases (to prefer move construction), 2044/// then falls back to treating them as lvalues if that failed. 2045ExprResult 2046Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 2047 const VarDecl *NRVOCandidate, 2048 QualType ResultType, 2049 Expr *Value, 2050 bool AllowNRVO) { 2051 // C++0x [class.copy]p33: 2052 // When the criteria for elision of a copy operation are met or would 2053 // be met save for the fact that the source object is a function 2054 // parameter, and the object to be copied is designated by an lvalue, 2055 // overload resolution to select the constructor for the copy is first 2056 // performed as if the object were designated by an rvalue. 2057 ExprResult Res = ExprError(); 2058 if (AllowNRVO && 2059 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 2060 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 2061 Value->getType(), CK_NoOp, Value, VK_XValue); 2062 2063 Expr *InitExpr = &AsRvalue; 2064 InitializationKind Kind 2065 = InitializationKind::CreateCopy(Value->getLocStart(), 2066 Value->getLocStart()); 2067 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 2068 2069 // [...] If overload resolution fails, or if the type of the first 2070 // parameter of the selected constructor is not an rvalue reference 2071 // to the object's type (possibly cv-qualified), overload resolution 2072 // is performed again, considering the object as an lvalue. 2073 if (Seq) { 2074 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 2075 StepEnd = Seq.step_end(); 2076 Step != StepEnd; ++Step) { 2077 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 2078 continue; 2079 2080 CXXConstructorDecl *Constructor 2081 = cast<CXXConstructorDecl>(Step->Function.Function); 2082 2083 const RValueReferenceType *RRefType 2084 = Constructor->getParamDecl(0)->getType() 2085 ->getAs<RValueReferenceType>(); 2086 2087 // If we don't meet the criteria, break out now. 2088 if (!RRefType || 2089 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 2090 Context.getTypeDeclType(Constructor->getParent()))) 2091 break; 2092 2093 // Promote "AsRvalue" to the heap, since we now need this 2094 // expression node to persist. 2095 Value = ImplicitCastExpr::Create(Context, Value->getType(), 2096 CK_NoOp, Value, 0, VK_XValue); 2097 2098 // Complete type-checking the initialization of the return type 2099 // using the constructor we found. 2100 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 2101 } 2102 } 2103 } 2104 2105 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 2106 // above, or overload resolution failed. Either way, we need to try 2107 // (again) now with the return value expression as written. 2108 if (Res.isInvalid()) 2109 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 2110 2111 return Res; 2112} 2113 2114/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements 2115/// for capturing scopes. 2116/// 2117StmtResult 2118Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 2119 // If this is the first return we've seen, infer the return type. 2120 // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those 2121 // rules which allows multiple return statements. 2122 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction()); 2123 if (CurCap->HasImplicitReturnType) { 2124 QualType ReturnT; 2125 if (RetValExp && !isa<InitListExpr>(RetValExp)) { 2126 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 2127 if (Result.isInvalid()) 2128 return StmtError(); 2129 RetValExp = Result.take(); 2130 2131 if (!RetValExp->isTypeDependent()) 2132 ReturnT = RetValExp->getType(); 2133 else 2134 ReturnT = Context.DependentTy; 2135 } else { 2136 if (RetValExp) { 2137 // C++11 [expr.lambda.prim]p4 bans inferring the result from an 2138 // initializer list, because it is not an expression (even 2139 // though we represent it as one). We still deduce 'void'. 2140 Diag(ReturnLoc, diag::err_lambda_return_init_list) 2141 << RetValExp->getSourceRange(); 2142 } 2143 2144 ReturnT = Context.VoidTy; 2145 } 2146 // We require the return types to strictly match here. 2147 if (!CurCap->ReturnType.isNull() && 2148 !CurCap->ReturnType->isDependentType() && 2149 !ReturnT->isDependentType() && 2150 !Context.hasSameType(ReturnT, CurCap->ReturnType)) { 2151 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) 2152 << ReturnT << CurCap->ReturnType 2153 << (getCurLambda() != 0); 2154 return StmtError(); 2155 } 2156 CurCap->ReturnType = ReturnT; 2157 } 2158 QualType FnRetType = CurCap->ReturnType; 2159 assert(!FnRetType.isNull()); 2160 2161 if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) { 2162 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 2163 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr); 2164 return StmtError(); 2165 } 2166 } else { 2167 LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CurCap); 2168 if (LSI->CallOperator->getType()->getAs<FunctionType>()->getNoReturnAttr()){ 2169 Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr); 2170 return StmtError(); 2171 } 2172 } 2173 2174 // Otherwise, verify that this result type matches the previous one. We are 2175 // pickier with blocks than for normal functions because we don't have GCC 2176 // compatibility to worry about here. 2177 const VarDecl *NRVOCandidate = 0; 2178 if (FnRetType->isDependentType()) { 2179 // Delay processing for now. TODO: there are lots of dependent 2180 // types we can conclusively prove aren't void. 2181 } else if (FnRetType->isVoidType()) { 2182 if (RetValExp && !isa<InitListExpr>(RetValExp) && 2183 !(getLangOpts().CPlusPlus && 2184 (RetValExp->isTypeDependent() || 2185 RetValExp->getType()->isVoidType()))) { 2186 if (!getLangOpts().CPlusPlus && 2187 RetValExp->getType()->isVoidType()) 2188 Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2; 2189 else { 2190 Diag(ReturnLoc, diag::err_return_block_has_expr); 2191 RetValExp = 0; 2192 } 2193 } 2194 } else if (!RetValExp) { 2195 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 2196 } else if (!RetValExp->isTypeDependent()) { 2197 // we have a non-void block with an expression, continue checking 2198 2199 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2200 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2201 // function return. 2202 2203 // In C++ the return statement is handled via a copy initialization. 2204 // the C version of which boils down to CheckSingleAssignmentConstraints. 2205 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2206 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2207 FnRetType, 2208 NRVOCandidate != 0); 2209 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2210 FnRetType, RetValExp); 2211 if (Res.isInvalid()) { 2212 // FIXME: Cleanup temporaries here, anyway? 2213 return StmtError(); 2214 } 2215 RetValExp = Res.take(); 2216 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2217 } 2218 2219 if (RetValExp) { 2220 CheckImplicitConversions(RetValExp, ReturnLoc); 2221 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2222 } 2223 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 2224 NRVOCandidate); 2225 2226 // If we need to check for the named return value optimization, save the 2227 // return statement in our scope for later processing. 2228 if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 2229 !CurContext->isDependentContext()) 2230 FunctionScopes.back()->Returns.push_back(Result); 2231 2232 return Owned(Result); 2233} 2234 2235StmtResult 2236Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 2237 // Check for unexpanded parameter packs. 2238 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 2239 return StmtError(); 2240 2241 if (isa<CapturingScopeInfo>(getCurFunction())) 2242 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp); 2243 2244 QualType FnRetType; 2245 QualType RelatedRetType; 2246 if (const FunctionDecl *FD = getCurFunctionDecl()) { 2247 FnRetType = FD->getResultType(); 2248 if (FD->hasAttr<NoReturnAttr>() || 2249 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 2250 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 2251 << FD->getDeclName(); 2252 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 2253 FnRetType = MD->getResultType(); 2254 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 2255 // In the implementation of a method with a related return type, the 2256 // type used to type-check the validity of return statements within the 2257 // method body is a pointer to the type of the class being implemented. 2258 RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 2259 RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType); 2260 } 2261 } else // If we don't have a function/method context, bail. 2262 return StmtError(); 2263 2264 ReturnStmt *Result = 0; 2265 if (FnRetType->isVoidType()) { 2266 if (RetValExp) { 2267 if (isa<InitListExpr>(RetValExp)) { 2268 // We simply never allow init lists as the return value of void 2269 // functions. This is compatible because this was never allowed before, 2270 // so there's no legacy code to deal with. 2271 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2272 int FunctionKind = 0; 2273 if (isa<ObjCMethodDecl>(CurDecl)) 2274 FunctionKind = 1; 2275 else if (isa<CXXConstructorDecl>(CurDecl)) 2276 FunctionKind = 2; 2277 else if (isa<CXXDestructorDecl>(CurDecl)) 2278 FunctionKind = 3; 2279 2280 Diag(ReturnLoc, diag::err_return_init_list) 2281 << CurDecl->getDeclName() << FunctionKind 2282 << RetValExp->getSourceRange(); 2283 2284 // Drop the expression. 2285 RetValExp = 0; 2286 } else if (!RetValExp->isTypeDependent()) { 2287 // C99 6.8.6.4p1 (ext_ since GCC warns) 2288 unsigned D = diag::ext_return_has_expr; 2289 if (RetValExp->getType()->isVoidType()) 2290 D = diag::ext_return_has_void_expr; 2291 else { 2292 ExprResult Result = Owned(RetValExp); 2293 Result = IgnoredValueConversions(Result.take()); 2294 if (Result.isInvalid()) 2295 return StmtError(); 2296 RetValExp = Result.take(); 2297 RetValExp = ImpCastExprToType(RetValExp, 2298 Context.VoidTy, CK_ToVoid).take(); 2299 } 2300 2301 // return (some void expression); is legal in C++. 2302 if (D != diag::ext_return_has_void_expr || 2303 !getLangOpts().CPlusPlus) { 2304 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2305 2306 int FunctionKind = 0; 2307 if (isa<ObjCMethodDecl>(CurDecl)) 2308 FunctionKind = 1; 2309 else if (isa<CXXConstructorDecl>(CurDecl)) 2310 FunctionKind = 2; 2311 else if (isa<CXXDestructorDecl>(CurDecl)) 2312 FunctionKind = 3; 2313 2314 Diag(ReturnLoc, D) 2315 << CurDecl->getDeclName() << FunctionKind 2316 << RetValExp->getSourceRange(); 2317 } 2318 } 2319 2320 if (RetValExp) { 2321 CheckImplicitConversions(RetValExp, ReturnLoc); 2322 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2323 } 2324 } 2325 2326 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 2327 } else if (!RetValExp && !FnRetType->isDependentType()) { 2328 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 2329 // C99 6.8.6.4p1 (ext_ since GCC warns) 2330 if (getLangOpts().C99) DiagID = diag::ext_return_missing_expr; 2331 2332 if (FunctionDecl *FD = getCurFunctionDecl()) 2333 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 2334 else 2335 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 2336 Result = new (Context) ReturnStmt(ReturnLoc); 2337 } else { 2338 const VarDecl *NRVOCandidate = 0; 2339 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 2340 // we have a non-void function with an expression, continue checking 2341 2342 if (!RelatedRetType.isNull()) { 2343 // If we have a related result type, perform an extra conversion here. 2344 // FIXME: The diagnostics here don't really describe what is happening. 2345 InitializedEntity Entity = 2346 InitializedEntity::InitializeTemporary(RelatedRetType); 2347 2348 ExprResult Res = PerformCopyInitialization(Entity, SourceLocation(), 2349 RetValExp); 2350 if (Res.isInvalid()) { 2351 // FIXME: Cleanup temporaries here, anyway? 2352 return StmtError(); 2353 } 2354 RetValExp = Res.takeAs<Expr>(); 2355 } 2356 2357 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2358 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2359 // function return. 2360 2361 // In C++ the return statement is handled via a copy initialization, 2362 // the C version of which boils down to CheckSingleAssignmentConstraints. 2363 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2364 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2365 FnRetType, 2366 NRVOCandidate != 0); 2367 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2368 FnRetType, RetValExp); 2369 if (Res.isInvalid()) { 2370 // FIXME: Cleanup temporaries here, anyway? 2371 return StmtError(); 2372 } 2373 2374 RetValExp = Res.takeAs<Expr>(); 2375 if (RetValExp) 2376 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2377 } 2378 2379 if (RetValExp) { 2380 CheckImplicitConversions(RetValExp, ReturnLoc); 2381 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2382 } 2383 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 2384 } 2385 2386 // If we need to check for the named return value optimization, save the 2387 // return statement in our scope for later processing. 2388 if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 2389 !CurContext->isDependentContext()) 2390 FunctionScopes.back()->Returns.push_back(Result); 2391 2392 return Owned(Result); 2393} 2394 2395/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 2396/// ignore "noop" casts in places where an lvalue is required by an inline asm. 2397/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 2398/// provide a strong guidance to not use it. 2399/// 2400/// This method checks to see if the argument is an acceptable l-value and 2401/// returns false if it is a case we can handle. 2402static bool CheckAsmLValue(const Expr *E, Sema &S) { 2403 // Type dependent expressions will be checked during instantiation. 2404 if (E->isTypeDependent()) 2405 return false; 2406 2407 if (E->isLValue()) 2408 return false; // Cool, this is an lvalue. 2409 2410 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 2411 // are supposed to allow. 2412 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 2413 if (E != E2 && E2->isLValue()) { 2414 if (!S.getLangOpts().HeinousExtensions) 2415 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 2416 << E->getSourceRange(); 2417 else 2418 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 2419 << E->getSourceRange(); 2420 // Accept, even if we emitted an error diagnostic. 2421 return false; 2422 } 2423 2424 // None of the above, just randomly invalid non-lvalue. 2425 return true; 2426} 2427 2428/// isOperandMentioned - Return true if the specified operand # is mentioned 2429/// anywhere in the decomposed asm string. 2430static bool isOperandMentioned(unsigned OpNo, 2431 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2432 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2433 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2434 if (!Piece.isOperand()) continue; 2435 2436 // If this is a reference to the input and if the input was the smaller 2437 // one, then we have to reject this asm. 2438 if (Piece.getOperandNo() == OpNo) 2439 return true; 2440 } 2441 2442 return false; 2443} 2444 2445StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2446 bool IsVolatile, unsigned NumOutputs, 2447 unsigned NumInputs, IdentifierInfo **Names, 2448 MultiExprArg constraints, MultiExprArg exprs, 2449 Expr *asmString, MultiExprArg clobbers, 2450 SourceLocation RParenLoc, bool MSAsm) { 2451 unsigned NumClobbers = clobbers.size(); 2452 StringLiteral **Constraints = 2453 reinterpret_cast<StringLiteral**>(constraints.get()); 2454 Expr **Exprs = exprs.get(); 2455 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2456 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2457 2458 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2459 2460 // The parser verifies that there is a string literal here. 2461 if (!AsmString->isAscii()) 2462 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2463 << AsmString->getSourceRange()); 2464 2465 for (unsigned i = 0; i != NumOutputs; i++) { 2466 StringLiteral *Literal = Constraints[i]; 2467 if (!Literal->isAscii()) 2468 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2469 << Literal->getSourceRange()); 2470 2471 StringRef OutputName; 2472 if (Names[i]) 2473 OutputName = Names[i]->getName(); 2474 2475 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2476 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2477 return StmtError(Diag(Literal->getLocStart(), 2478 diag::err_asm_invalid_output_constraint) 2479 << Info.getConstraintStr()); 2480 2481 // Check that the output exprs are valid lvalues. 2482 Expr *OutputExpr = Exprs[i]; 2483 if (CheckAsmLValue(OutputExpr, *this)) { 2484 return StmtError(Diag(OutputExpr->getLocStart(), 2485 diag::err_asm_invalid_lvalue_in_output) 2486 << OutputExpr->getSourceRange()); 2487 } 2488 2489 OutputConstraintInfos.push_back(Info); 2490 } 2491 2492 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2493 2494 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2495 StringLiteral *Literal = Constraints[i]; 2496 if (!Literal->isAscii()) 2497 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2498 << Literal->getSourceRange()); 2499 2500 StringRef InputName; 2501 if (Names[i]) 2502 InputName = Names[i]->getName(); 2503 2504 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2505 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2506 NumOutputs, Info)) { 2507 return StmtError(Diag(Literal->getLocStart(), 2508 diag::err_asm_invalid_input_constraint) 2509 << Info.getConstraintStr()); 2510 } 2511 2512 Expr *InputExpr = Exprs[i]; 2513 2514 // Only allow void types for memory constraints. 2515 if (Info.allowsMemory() && !Info.allowsRegister()) { 2516 if (CheckAsmLValue(InputExpr, *this)) 2517 return StmtError(Diag(InputExpr->getLocStart(), 2518 diag::err_asm_invalid_lvalue_in_input) 2519 << Info.getConstraintStr() 2520 << InputExpr->getSourceRange()); 2521 } 2522 2523 if (Info.allowsRegister()) { 2524 if (InputExpr->getType()->isVoidType()) { 2525 return StmtError(Diag(InputExpr->getLocStart(), 2526 diag::err_asm_invalid_type_in_input) 2527 << InputExpr->getType() << Info.getConstraintStr() 2528 << InputExpr->getSourceRange()); 2529 } 2530 } 2531 2532 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2533 if (Result.isInvalid()) 2534 return StmtError(); 2535 2536 Exprs[i] = Result.take(); 2537 InputConstraintInfos.push_back(Info); 2538 } 2539 2540 // Check that the clobbers are valid. 2541 for (unsigned i = 0; i != NumClobbers; i++) { 2542 StringLiteral *Literal = Clobbers[i]; 2543 if (!Literal->isAscii()) 2544 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2545 << Literal->getSourceRange()); 2546 2547 StringRef Clobber = Literal->getString(); 2548 2549 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2550 return StmtError(Diag(Literal->getLocStart(), 2551 diag::err_asm_unknown_register_name) << Clobber); 2552 } 2553 2554 AsmStmt *NS = 2555 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2556 NumOutputs, NumInputs, Names, Constraints, Exprs, 2557 AsmString, NumClobbers, Clobbers, RParenLoc); 2558 // Validate the asm string, ensuring it makes sense given the operands we 2559 // have. 2560 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2561 unsigned DiagOffs; 2562 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2563 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2564 << AsmString->getSourceRange(); 2565 return StmtError(); 2566 } 2567 2568 // Validate tied input operands for type mismatches. 2569 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2570 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2571 2572 // If this is a tied constraint, verify that the output and input have 2573 // either exactly the same type, or that they are int/ptr operands with the 2574 // same size (int/long, int*/long, are ok etc). 2575 if (!Info.hasTiedOperand()) continue; 2576 2577 unsigned TiedTo = Info.getTiedOperand(); 2578 unsigned InputOpNo = i+NumOutputs; 2579 Expr *OutputExpr = Exprs[TiedTo]; 2580 Expr *InputExpr = Exprs[InputOpNo]; 2581 2582 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2583 continue; 2584 2585 QualType InTy = InputExpr->getType(); 2586 QualType OutTy = OutputExpr->getType(); 2587 if (Context.hasSameType(InTy, OutTy)) 2588 continue; // All types can be tied to themselves. 2589 2590 // Decide if the input and output are in the same domain (integer/ptr or 2591 // floating point. 2592 enum AsmDomain { 2593 AD_Int, AD_FP, AD_Other 2594 } InputDomain, OutputDomain; 2595 2596 if (InTy->isIntegerType() || InTy->isPointerType()) 2597 InputDomain = AD_Int; 2598 else if (InTy->isRealFloatingType()) 2599 InputDomain = AD_FP; 2600 else 2601 InputDomain = AD_Other; 2602 2603 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2604 OutputDomain = AD_Int; 2605 else if (OutTy->isRealFloatingType()) 2606 OutputDomain = AD_FP; 2607 else 2608 OutputDomain = AD_Other; 2609 2610 // They are ok if they are the same size and in the same domain. This 2611 // allows tying things like: 2612 // void* to int* 2613 // void* to int if they are the same size. 2614 // double to long double if they are the same size. 2615 // 2616 uint64_t OutSize = Context.getTypeSize(OutTy); 2617 uint64_t InSize = Context.getTypeSize(InTy); 2618 if (OutSize == InSize && InputDomain == OutputDomain && 2619 InputDomain != AD_Other) 2620 continue; 2621 2622 // If the smaller input/output operand is not mentioned in the asm string, 2623 // then we can promote the smaller one to a larger input and the asm string 2624 // won't notice. 2625 bool SmallerValueMentioned = false; 2626 2627 // If this is a reference to the input and if the input was the smaller 2628 // one, then we have to reject this asm. 2629 if (isOperandMentioned(InputOpNo, Pieces)) { 2630 // This is a use in the asm string of the smaller operand. Since we 2631 // codegen this by promoting to a wider value, the asm will get printed 2632 // "wrong". 2633 SmallerValueMentioned |= InSize < OutSize; 2634 } 2635 if (isOperandMentioned(TiedTo, Pieces)) { 2636 // If this is a reference to the output, and if the output is the larger 2637 // value, then it's ok because we'll promote the input to the larger type. 2638 SmallerValueMentioned |= OutSize < InSize; 2639 } 2640 2641 // If the smaller value wasn't mentioned in the asm string, and if the 2642 // output was a register, just extend the shorter one to the size of the 2643 // larger one. 2644 if (!SmallerValueMentioned && InputDomain != AD_Other && 2645 OutputConstraintInfos[TiedTo].allowsRegister()) 2646 continue; 2647 2648 // Either both of the operands were mentioned or the smaller one was 2649 // mentioned. One more special case that we'll allow: if the tied input is 2650 // integer, unmentioned, and is a constant, then we'll allow truncating it 2651 // down to the size of the destination. 2652 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2653 !isOperandMentioned(InputOpNo, Pieces) && 2654 InputExpr->isEvaluatable(Context)) { 2655 CastKind castKind = 2656 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2657 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2658 Exprs[InputOpNo] = InputExpr; 2659 NS->setInputExpr(i, InputExpr); 2660 continue; 2661 } 2662 2663 Diag(InputExpr->getLocStart(), 2664 diag::err_asm_tying_incompatible_types) 2665 << InTy << OutTy << OutputExpr->getSourceRange() 2666 << InputExpr->getSourceRange(); 2667 return StmtError(); 2668 } 2669 2670 return Owned(NS); 2671} 2672 2673StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, 2674 std::string &AsmString, 2675 SourceLocation EndLoc) { 2676 MSAsmStmt *NS = 2677 new (Context) MSAsmStmt(Context, AsmLoc, AsmString, EndLoc); 2678 2679 return Owned(NS); 2680} 2681 2682StmtResult 2683Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2684 SourceLocation RParen, Decl *Parm, 2685 Stmt *Body) { 2686 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2687 if (Var && Var->isInvalidDecl()) 2688 return StmtError(); 2689 2690 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2691} 2692 2693StmtResult 2694Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2695 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2696} 2697 2698StmtResult 2699Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2700 MultiStmtArg CatchStmts, Stmt *Finally) { 2701 if (!getLangOpts().ObjCExceptions) 2702 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2703 2704 getCurFunction()->setHasBranchProtectedScope(); 2705 unsigned NumCatchStmts = CatchStmts.size(); 2706 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2707 CatchStmts.release(), 2708 NumCatchStmts, 2709 Finally)); 2710} 2711 2712StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) { 2713 if (Throw) { 2714 ExprResult Result = DefaultLvalueConversion(Throw); 2715 if (Result.isInvalid()) 2716 return StmtError(); 2717 2718 Throw = MaybeCreateExprWithCleanups(Result.take()); 2719 QualType ThrowType = Throw->getType(); 2720 // Make sure the expression type is an ObjC pointer or "void *". 2721 if (!ThrowType->isDependentType() && 2722 !ThrowType->isObjCObjectPointerType()) { 2723 const PointerType *PT = ThrowType->getAs<PointerType>(); 2724 if (!PT || !PT->getPointeeType()->isVoidType()) 2725 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2726 << Throw->getType() << Throw->getSourceRange()); 2727 } 2728 } 2729 2730 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2731} 2732 2733StmtResult 2734Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2735 Scope *CurScope) { 2736 if (!getLangOpts().ObjCExceptions) 2737 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2738 2739 if (!Throw) { 2740 // @throw without an expression designates a rethrow (which much occur 2741 // in the context of an @catch clause). 2742 Scope *AtCatchParent = CurScope; 2743 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2744 AtCatchParent = AtCatchParent->getParent(); 2745 if (!AtCatchParent) 2746 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2747 } 2748 2749 return BuildObjCAtThrowStmt(AtLoc, Throw); 2750} 2751 2752ExprResult 2753Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 2754 ExprResult result = DefaultLvalueConversion(operand); 2755 if (result.isInvalid()) 2756 return ExprError(); 2757 operand = result.take(); 2758 2759 // Make sure the expression type is an ObjC pointer or "void *". 2760 QualType type = operand->getType(); 2761 if (!type->isDependentType() && 2762 !type->isObjCObjectPointerType()) { 2763 const PointerType *pointerType = type->getAs<PointerType>(); 2764 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 2765 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 2766 << type << operand->getSourceRange(); 2767 } 2768 2769 // The operand to @synchronized is a full-expression. 2770 return MaybeCreateExprWithCleanups(operand); 2771} 2772 2773StmtResult 2774Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2775 Stmt *SyncBody) { 2776 // We can't jump into or indirect-jump out of a @synchronized block. 2777 getCurFunction()->setHasBranchProtectedScope(); 2778 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2779} 2780 2781/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2782/// and creates a proper catch handler from them. 2783StmtResult 2784Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2785 Stmt *HandlerBlock) { 2786 // There's nothing to test that ActOnExceptionDecl didn't already test. 2787 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2788 cast_or_null<VarDecl>(ExDecl), 2789 HandlerBlock)); 2790} 2791 2792StmtResult 2793Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2794 getCurFunction()->setHasBranchProtectedScope(); 2795 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2796} 2797 2798namespace { 2799 2800class TypeWithHandler { 2801 QualType t; 2802 CXXCatchStmt *stmt; 2803public: 2804 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2805 : t(type), stmt(statement) {} 2806 2807 // An arbitrary order is fine as long as it places identical 2808 // types next to each other. 2809 bool operator<(const TypeWithHandler &y) const { 2810 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2811 return true; 2812 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2813 return false; 2814 else 2815 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2816 } 2817 2818 bool operator==(const TypeWithHandler& other) const { 2819 return t == other.t; 2820 } 2821 2822 CXXCatchStmt *getCatchStmt() const { return stmt; } 2823 SourceLocation getTypeSpecStartLoc() const { 2824 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2825 } 2826}; 2827 2828} 2829 2830/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2831/// handlers and creates a try statement from them. 2832StmtResult 2833Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2834 MultiStmtArg RawHandlers) { 2835 // Don't report an error if 'try' is used in system headers. 2836 if (!getLangOpts().CXXExceptions && 2837 !getSourceManager().isInSystemHeader(TryLoc)) 2838 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2839 2840 unsigned NumHandlers = RawHandlers.size(); 2841 assert(NumHandlers > 0 && 2842 "The parser shouldn't call this if there are no handlers."); 2843 Stmt **Handlers = RawHandlers.get(); 2844 2845 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2846 2847 for (unsigned i = 0; i < NumHandlers; ++i) { 2848 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2849 if (!Handler->getExceptionDecl()) { 2850 if (i < NumHandlers - 1) 2851 return StmtError(Diag(Handler->getLocStart(), 2852 diag::err_early_catch_all)); 2853 2854 continue; 2855 } 2856 2857 const QualType CaughtType = Handler->getCaughtType(); 2858 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2859 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2860 } 2861 2862 // Detect handlers for the same type as an earlier one. 2863 if (NumHandlers > 1) { 2864 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2865 2866 TypeWithHandler prev = TypesWithHandlers[0]; 2867 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2868 TypeWithHandler curr = TypesWithHandlers[i]; 2869 2870 if (curr == prev) { 2871 Diag(curr.getTypeSpecStartLoc(), 2872 diag::warn_exception_caught_by_earlier_handler) 2873 << curr.getCatchStmt()->getCaughtType().getAsString(); 2874 Diag(prev.getTypeSpecStartLoc(), 2875 diag::note_previous_exception_handler) 2876 << prev.getCatchStmt()->getCaughtType().getAsString(); 2877 } 2878 2879 prev = curr; 2880 } 2881 } 2882 2883 getCurFunction()->setHasBranchProtectedScope(); 2884 2885 // FIXME: We should detect handlers that cannot catch anything because an 2886 // earlier handler catches a superclass. Need to find a method that is not 2887 // quadratic for this. 2888 // Neither of these are explicitly forbidden, but every compiler detects them 2889 // and warns. 2890 2891 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2892 Handlers, NumHandlers)); 2893} 2894 2895StmtResult 2896Sema::ActOnSEHTryBlock(bool IsCXXTry, 2897 SourceLocation TryLoc, 2898 Stmt *TryBlock, 2899 Stmt *Handler) { 2900 assert(TryBlock && Handler); 2901 2902 getCurFunction()->setHasBranchProtectedScope(); 2903 2904 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2905} 2906 2907StmtResult 2908Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2909 Expr *FilterExpr, 2910 Stmt *Block) { 2911 assert(FilterExpr && Block); 2912 2913 if(!FilterExpr->getType()->isIntegerType()) { 2914 return StmtError(Diag(FilterExpr->getExprLoc(), 2915 diag::err_filter_expression_integral) 2916 << FilterExpr->getType()); 2917 } 2918 2919 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2920} 2921 2922StmtResult 2923Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2924 Stmt *Block) { 2925 assert(Block); 2926 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2927} 2928 2929StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 2930 bool IsIfExists, 2931 NestedNameSpecifierLoc QualifierLoc, 2932 DeclarationNameInfo NameInfo, 2933 Stmt *Nested) 2934{ 2935 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 2936 QualifierLoc, NameInfo, 2937 cast<CompoundStmt>(Nested)); 2938} 2939 2940 2941StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 2942 bool IsIfExists, 2943 CXXScopeSpec &SS, 2944 UnqualifiedId &Name, 2945 Stmt *Nested) { 2946 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 2947 SS.getWithLocInContext(Context), 2948 GetNameFromUnqualifiedId(Name), 2949 Nested); 2950} 2951