SemaStmt.cpp revision d1376ee0945a4eba0590ae33d14bade860b08a7d
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements semantic analysis for statements. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Sema/SemaInternal.h" 15#include "clang/Sema/Scope.h" 16#include "clang/Sema/ScopeInfo.h" 17#include "clang/Sema/Initialization.h" 18#include "clang/Sema/Lookup.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/CharUnits.h" 21#include "clang/AST/DeclObjC.h" 22#include "clang/AST/EvaluatedExprVisitor.h" 23#include "clang/AST/ExprCXX.h" 24#include "clang/AST/ExprObjC.h" 25#include "clang/AST/StmtObjC.h" 26#include "clang/AST/StmtCXX.h" 27#include "clang/AST/TypeLoc.h" 28#include "clang/Lex/Preprocessor.h" 29#include "clang/Basic/TargetInfo.h" 30#include "llvm/ADT/ArrayRef.h" 31#include "llvm/ADT/STLExtras.h" 32#include "llvm/ADT/SmallPtrSet.h" 33#include "llvm/ADT/SmallVector.h" 34using namespace clang; 35using namespace sema; 36 37StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 38 Expr *E = expr.get(); 39 if (!E) // FIXME: FullExprArg has no error state? 40 return StmtError(); 41 42 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 43 // void expression for its side effects. Conversion to void allows any 44 // operand, even incomplete types. 45 46 // Same thing in for stmt first clause (when expr) and third clause. 47 return Owned(static_cast<Stmt*>(E)); 48} 49 50 51StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, 52 bool HasLeadingEmptyMacro) { 53 return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro)); 54} 55 56StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 57 SourceLocation EndLoc) { 58 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 59 60 // If we have an invalid decl, just return an error. 61 if (DG.isNull()) return StmtError(); 62 63 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 64} 65 66void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 67 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 68 69 // If we have an invalid decl, just return. 70 if (DG.isNull() || !DG.isSingleDecl()) return; 71 VarDecl *var = cast<VarDecl>(DG.getSingleDecl()); 72 73 // suppress any potential 'unused variable' warning. 74 var->setUsed(); 75 76 // foreach variables are never actually initialized in the way that 77 // the parser came up with. 78 var->setInit(0); 79 80 // In ARC, we don't need to retain the iteration variable of a fast 81 // enumeration loop. Rather than actually trying to catch that 82 // during declaration processing, we remove the consequences here. 83 if (getLangOpts().ObjCAutoRefCount) { 84 QualType type = var->getType(); 85 86 // Only do this if we inferred the lifetime. Inferred lifetime 87 // will show up as a local qualifier because explicit lifetime 88 // should have shown up as an AttributedType instead. 89 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { 90 // Add 'const' and mark the variable as pseudo-strong. 91 var->setType(type.withConst()); 92 var->setARCPseudoStrong(true); 93 } 94 } 95} 96 97/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='. 98/// 99/// Adding a cast to void (or other expression wrappers) will prevent the 100/// warning from firing. 101static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) { 102 SourceLocation Loc; 103 bool IsNotEqual, CanAssign; 104 105 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) { 106 if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE) 107 return false; 108 109 Loc = Op->getOperatorLoc(); 110 IsNotEqual = Op->getOpcode() == BO_NE; 111 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue(); 112 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) { 113 if (Op->getOperator() != OO_EqualEqual && 114 Op->getOperator() != OO_ExclaimEqual) 115 return false; 116 117 Loc = Op->getOperatorLoc(); 118 IsNotEqual = Op->getOperator() == OO_ExclaimEqual; 119 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue(); 120 } else { 121 // Not a typo-prone comparison. 122 return false; 123 } 124 125 // Suppress warnings when the operator, suspicious as it may be, comes from 126 // a macro expansion. 127 if (Loc.isMacroID()) 128 return false; 129 130 S.Diag(Loc, diag::warn_unused_comparison) 131 << (unsigned)IsNotEqual << E->getSourceRange(); 132 133 // If the LHS is a plausible entity to assign to, provide a fixit hint to 134 // correct common typos. 135 if (CanAssign) { 136 if (IsNotEqual) 137 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign) 138 << FixItHint::CreateReplacement(Loc, "|="); 139 else 140 S.Diag(Loc, diag::note_equality_comparison_to_assign) 141 << FixItHint::CreateReplacement(Loc, "="); 142 } 143 144 return true; 145} 146 147void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 148 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 149 return DiagnoseUnusedExprResult(Label->getSubStmt()); 150 151 const Expr *E = dyn_cast_or_null<Expr>(S); 152 if (!E) 153 return; 154 155 SourceLocation Loc; 156 SourceRange R1, R2; 157 if (SourceMgr.isInSystemMacro(E->getExprLoc()) || 158 !E->isUnusedResultAWarning(Loc, R1, R2, Context)) 159 return; 160 161 // Okay, we have an unused result. Depending on what the base expression is, 162 // we might want to make a more specific diagnostic. Check for one of these 163 // cases now. 164 unsigned DiagID = diag::warn_unused_expr; 165 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 166 E = Temps->getSubExpr(); 167 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 168 E = TempExpr->getSubExpr(); 169 170 if (DiagnoseUnusedComparison(*this, E)) 171 return; 172 173 E = E->IgnoreParenImpCasts(); 174 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 175 if (E->getType()->isVoidType()) 176 return; 177 178 // If the callee has attribute pure, const, or warn_unused_result, warn with 179 // a more specific message to make it clear what is happening. 180 if (const Decl *FD = CE->getCalleeDecl()) { 181 if (FD->getAttr<WarnUnusedResultAttr>()) { 182 Diag(Loc, diag::warn_unused_result) << R1 << R2; 183 return; 184 } 185 if (FD->getAttr<PureAttr>()) { 186 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 187 return; 188 } 189 if (FD->getAttr<ConstAttr>()) { 190 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 191 return; 192 } 193 } 194 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 195 if (getLangOpts().ObjCAutoRefCount && ME->isDelegateInitCall()) { 196 Diag(Loc, diag::err_arc_unused_init_message) << R1; 197 return; 198 } 199 const ObjCMethodDecl *MD = ME->getMethodDecl(); 200 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 201 Diag(Loc, diag::warn_unused_result) << R1 << R2; 202 return; 203 } 204 } else if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(E)) { 205 const Expr *Source = POE->getSyntacticForm(); 206 if (isa<ObjCSubscriptRefExpr>(Source)) 207 DiagID = diag::warn_unused_container_subscript_expr; 208 else 209 DiagID = diag::warn_unused_property_expr; 210 } else if (const CXXFunctionalCastExpr *FC 211 = dyn_cast<CXXFunctionalCastExpr>(E)) { 212 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 213 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 214 return; 215 } 216 // Diagnose "(void*) blah" as a typo for "(void) blah". 217 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 218 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 219 QualType T = TI->getType(); 220 221 // We really do want to use the non-canonical type here. 222 if (T == Context.VoidPtrTy) { 223 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 224 225 Diag(Loc, diag::warn_unused_voidptr) 226 << FixItHint::CreateRemoval(TL.getStarLoc()); 227 return; 228 } 229 } 230 231 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 232} 233 234void Sema::ActOnStartOfCompoundStmt() { 235 PushCompoundScope(); 236} 237 238void Sema::ActOnFinishOfCompoundStmt() { 239 PopCompoundScope(); 240} 241 242sema::CompoundScopeInfo &Sema::getCurCompoundScope() const { 243 return getCurFunction()->CompoundScopes.back(); 244} 245 246StmtResult 247Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 248 MultiStmtArg elts, bool isStmtExpr) { 249 unsigned NumElts = elts.size(); 250 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 251 // If we're in C89 mode, check that we don't have any decls after stmts. If 252 // so, emit an extension diagnostic. 253 if (!getLangOpts().C99 && !getLangOpts().CPlusPlus) { 254 // Note that __extension__ can be around a decl. 255 unsigned i = 0; 256 // Skip over all declarations. 257 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 258 /*empty*/; 259 260 // We found the end of the list or a statement. Scan for another declstmt. 261 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 262 /*empty*/; 263 264 if (i != NumElts) { 265 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 266 Diag(D->getLocation(), diag::ext_mixed_decls_code); 267 } 268 } 269 // Warn about unused expressions in statements. 270 for (unsigned i = 0; i != NumElts; ++i) { 271 // Ignore statements that are last in a statement expression. 272 if (isStmtExpr && i == NumElts - 1) 273 continue; 274 275 DiagnoseUnusedExprResult(Elts[i]); 276 } 277 278 // Check for suspicious empty body (null statement) in `for' and `while' 279 // statements. Don't do anything for template instantiations, this just adds 280 // noise. 281 if (NumElts != 0 && !CurrentInstantiationScope && 282 getCurCompoundScope().HasEmptyLoopBodies) { 283 for (unsigned i = 0; i != NumElts - 1; ++i) 284 DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]); 285 } 286 287 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 288} 289 290StmtResult 291Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 292 SourceLocation DotDotDotLoc, Expr *RHSVal, 293 SourceLocation ColonLoc) { 294 assert((LHSVal != 0) && "missing expression in case statement"); 295 296 if (getCurFunction()->SwitchStack.empty()) { 297 Diag(CaseLoc, diag::err_case_not_in_switch); 298 return StmtError(); 299 } 300 301 if (!getLangOpts().CPlusPlus0x) { 302 // C99 6.8.4.2p3: The expression shall be an integer constant. 303 // However, GCC allows any evaluatable integer expression. 304 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) { 305 LHSVal = VerifyIntegerConstantExpression(LHSVal).take(); 306 if (!LHSVal) 307 return StmtError(); 308 } 309 310 // GCC extension: The expression shall be an integer constant. 311 312 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) { 313 RHSVal = VerifyIntegerConstantExpression(RHSVal).take(); 314 // Recover from an error by just forgetting about it. 315 } 316 } 317 318 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 319 ColonLoc); 320 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 321 return Owned(CS); 322} 323 324/// ActOnCaseStmtBody - This installs a statement as the body of a case. 325void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 326 DiagnoseUnusedExprResult(SubStmt); 327 328 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 329 CS->setSubStmt(SubStmt); 330} 331 332StmtResult 333Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 334 Stmt *SubStmt, Scope *CurScope) { 335 DiagnoseUnusedExprResult(SubStmt); 336 337 if (getCurFunction()->SwitchStack.empty()) { 338 Diag(DefaultLoc, diag::err_default_not_in_switch); 339 return Owned(SubStmt); 340 } 341 342 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 343 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 344 return Owned(DS); 345} 346 347StmtResult 348Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 349 SourceLocation ColonLoc, Stmt *SubStmt) { 350 // If the label was multiply defined, reject it now. 351 if (TheDecl->getStmt()) { 352 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 353 Diag(TheDecl->getLocation(), diag::note_previous_definition); 354 return Owned(SubStmt); 355 } 356 357 // Otherwise, things are good. Fill in the declaration and return it. 358 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 359 TheDecl->setStmt(LS); 360 if (!TheDecl->isGnuLocal()) 361 TheDecl->setLocation(IdentLoc); 362 return Owned(LS); 363} 364 365StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc, 366 const AttrVec &Attrs, 367 Stmt *SubStmt) { 368 // Fill in the declaration and return it. Variable length will require to 369 // change this to AttributedStmt::Create(Context, ....); 370 // and probably using ArrayRef 371 AttributedStmt *LS = new (Context) AttributedStmt(AttrLoc, Attrs, SubStmt); 372 return Owned(LS); 373} 374 375StmtResult 376Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 377 Stmt *thenStmt, SourceLocation ElseLoc, 378 Stmt *elseStmt) { 379 ExprResult CondResult(CondVal.release()); 380 381 VarDecl *ConditionVar = 0; 382 if (CondVar) { 383 ConditionVar = cast<VarDecl>(CondVar); 384 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 385 if (CondResult.isInvalid()) 386 return StmtError(); 387 } 388 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 389 if (!ConditionExpr) 390 return StmtError(); 391 392 DiagnoseUnusedExprResult(thenStmt); 393 394 if (!elseStmt) { 395 DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt, 396 diag::warn_empty_if_body); 397 } 398 399 DiagnoseUnusedExprResult(elseStmt); 400 401 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 402 thenStmt, ElseLoc, elseStmt)); 403} 404 405/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 406/// the specified width and sign. If an overflow occurs, detect it and emit 407/// the specified diagnostic. 408void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 409 unsigned NewWidth, bool NewSign, 410 SourceLocation Loc, 411 unsigned DiagID) { 412 // Perform a conversion to the promoted condition type if needed. 413 if (NewWidth > Val.getBitWidth()) { 414 // If this is an extension, just do it. 415 Val = Val.extend(NewWidth); 416 Val.setIsSigned(NewSign); 417 418 // If the input was signed and negative and the output is 419 // unsigned, don't bother to warn: this is implementation-defined 420 // behavior. 421 // FIXME: Introduce a second, default-ignored warning for this case? 422 } else if (NewWidth < Val.getBitWidth()) { 423 // If this is a truncation, check for overflow. 424 llvm::APSInt ConvVal(Val); 425 ConvVal = ConvVal.trunc(NewWidth); 426 ConvVal.setIsSigned(NewSign); 427 ConvVal = ConvVal.extend(Val.getBitWidth()); 428 ConvVal.setIsSigned(Val.isSigned()); 429 if (ConvVal != Val) 430 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 431 432 // Regardless of whether a diagnostic was emitted, really do the 433 // truncation. 434 Val = Val.trunc(NewWidth); 435 Val.setIsSigned(NewSign); 436 } else if (NewSign != Val.isSigned()) { 437 // Convert the sign to match the sign of the condition. This can cause 438 // overflow as well: unsigned(INTMIN) 439 // We don't diagnose this overflow, because it is implementation-defined 440 // behavior. 441 // FIXME: Introduce a second, default-ignored warning for this case? 442 llvm::APSInt OldVal(Val); 443 Val.setIsSigned(NewSign); 444 } 445} 446 447namespace { 448 struct CaseCompareFunctor { 449 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 450 const llvm::APSInt &RHS) { 451 return LHS.first < RHS; 452 } 453 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 454 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 455 return LHS.first < RHS.first; 456 } 457 bool operator()(const llvm::APSInt &LHS, 458 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 459 return LHS < RHS.first; 460 } 461 }; 462} 463 464/// CmpCaseVals - Comparison predicate for sorting case values. 465/// 466static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 467 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 468 if (lhs.first < rhs.first) 469 return true; 470 471 if (lhs.first == rhs.first && 472 lhs.second->getCaseLoc().getRawEncoding() 473 < rhs.second->getCaseLoc().getRawEncoding()) 474 return true; 475 return false; 476} 477 478/// CmpEnumVals - Comparison predicate for sorting enumeration values. 479/// 480static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 481 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 482{ 483 return lhs.first < rhs.first; 484} 485 486/// EqEnumVals - Comparison preficate for uniqing enumeration values. 487/// 488static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 489 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 490{ 491 return lhs.first == rhs.first; 492} 493 494/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 495/// potentially integral-promoted expression @p expr. 496static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 497 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 498 expr = cleanups->getSubExpr(); 499 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 500 if (impcast->getCastKind() != CK_IntegralCast) break; 501 expr = impcast->getSubExpr(); 502 } 503 return expr->getType(); 504} 505 506StmtResult 507Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 508 Decl *CondVar) { 509 ExprResult CondResult; 510 511 VarDecl *ConditionVar = 0; 512 if (CondVar) { 513 ConditionVar = cast<VarDecl>(CondVar); 514 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 515 if (CondResult.isInvalid()) 516 return StmtError(); 517 518 Cond = CondResult.release(); 519 } 520 521 if (!Cond) 522 return StmtError(); 523 524 class SwitchConvertDiagnoser : public ICEConvertDiagnoser { 525 Expr *Cond; 526 527 public: 528 SwitchConvertDiagnoser(Expr *Cond) 529 : ICEConvertDiagnoser(false, true), Cond(Cond) { } 530 531 virtual DiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc, 532 QualType T) { 533 return S.Diag(Loc, diag::err_typecheck_statement_requires_integer) << T; 534 } 535 536 virtual DiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc, 537 QualType T) { 538 return S.Diag(Loc, diag::err_switch_incomplete_class_type) 539 << T << Cond->getSourceRange(); 540 } 541 542 virtual DiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc, 543 QualType T, 544 QualType ConvTy) { 545 return S.Diag(Loc, diag::err_switch_explicit_conversion) << T << ConvTy; 546 } 547 548 virtual DiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv, 549 QualType ConvTy) { 550 return S.Diag(Conv->getLocation(), diag::note_switch_conversion) 551 << ConvTy->isEnumeralType() << ConvTy; 552 } 553 554 virtual DiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc, 555 QualType T) { 556 return S.Diag(Loc, diag::err_switch_multiple_conversions) << T; 557 } 558 559 virtual DiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv, 560 QualType ConvTy) { 561 return S.Diag(Conv->getLocation(), diag::note_switch_conversion) 562 << ConvTy->isEnumeralType() << ConvTy; 563 } 564 565 virtual DiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc, 566 QualType T, 567 QualType ConvTy) { 568 return DiagnosticBuilder::getEmpty(); 569 } 570 } SwitchDiagnoser(Cond); 571 572 CondResult 573 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, SwitchDiagnoser, 574 /*AllowScopedEnumerations*/ true); 575 if (CondResult.isInvalid()) return StmtError(); 576 Cond = CondResult.take(); 577 578 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 579 CondResult = UsualUnaryConversions(Cond); 580 if (CondResult.isInvalid()) return StmtError(); 581 Cond = CondResult.take(); 582 583 if (!CondVar) { 584 CheckImplicitConversions(Cond, SwitchLoc); 585 CondResult = MaybeCreateExprWithCleanups(Cond); 586 if (CondResult.isInvalid()) 587 return StmtError(); 588 Cond = CondResult.take(); 589 } 590 591 getCurFunction()->setHasBranchIntoScope(); 592 593 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 594 getCurFunction()->SwitchStack.push_back(SS); 595 return Owned(SS); 596} 597 598static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 599 if (Val.getBitWidth() < BitWidth) 600 Val = Val.extend(BitWidth); 601 else if (Val.getBitWidth() > BitWidth) 602 Val = Val.trunc(BitWidth); 603 Val.setIsSigned(IsSigned); 604} 605 606StmtResult 607Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 608 Stmt *BodyStmt) { 609 SwitchStmt *SS = cast<SwitchStmt>(Switch); 610 assert(SS == getCurFunction()->SwitchStack.back() && 611 "switch stack missing push/pop!"); 612 613 SS->setBody(BodyStmt, SwitchLoc); 614 getCurFunction()->SwitchStack.pop_back(); 615 616 Expr *CondExpr = SS->getCond(); 617 if (!CondExpr) return StmtError(); 618 619 QualType CondType = CondExpr->getType(); 620 621 Expr *CondExprBeforePromotion = CondExpr; 622 QualType CondTypeBeforePromotion = 623 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 624 625 // C++ 6.4.2.p2: 626 // Integral promotions are performed (on the switch condition). 627 // 628 // A case value unrepresentable by the original switch condition 629 // type (before the promotion) doesn't make sense, even when it can 630 // be represented by the promoted type. Therefore we need to find 631 // the pre-promotion type of the switch condition. 632 if (!CondExpr->isTypeDependent()) { 633 // We have already converted the expression to an integral or enumeration 634 // type, when we started the switch statement. If we don't have an 635 // appropriate type now, just return an error. 636 if (!CondType->isIntegralOrEnumerationType()) 637 return StmtError(); 638 639 if (CondExpr->isKnownToHaveBooleanValue()) { 640 // switch(bool_expr) {...} is often a programmer error, e.g. 641 // switch(n && mask) { ... } // Doh - should be "n & mask". 642 // One can always use an if statement instead of switch(bool_expr). 643 Diag(SwitchLoc, diag::warn_bool_switch_condition) 644 << CondExpr->getSourceRange(); 645 } 646 } 647 648 // Get the bitwidth of the switched-on value before promotions. We must 649 // convert the integer case values to this width before comparison. 650 bool HasDependentValue 651 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 652 unsigned CondWidth 653 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 654 bool CondIsSigned 655 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 656 657 // Accumulate all of the case values in a vector so that we can sort them 658 // and detect duplicates. This vector contains the APInt for the case after 659 // it has been converted to the condition type. 660 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 661 CaseValsTy CaseVals; 662 663 // Keep track of any GNU case ranges we see. The APSInt is the low value. 664 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 665 CaseRangesTy CaseRanges; 666 667 DefaultStmt *TheDefaultStmt = 0; 668 669 bool CaseListIsErroneous = false; 670 671 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 672 SC = SC->getNextSwitchCase()) { 673 674 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 675 if (TheDefaultStmt) { 676 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 677 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 678 679 // FIXME: Remove the default statement from the switch block so that 680 // we'll return a valid AST. This requires recursing down the AST and 681 // finding it, not something we are set up to do right now. For now, 682 // just lop the entire switch stmt out of the AST. 683 CaseListIsErroneous = true; 684 } 685 TheDefaultStmt = DS; 686 687 } else { 688 CaseStmt *CS = cast<CaseStmt>(SC); 689 690 Expr *Lo = CS->getLHS(); 691 692 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 693 HasDependentValue = true; 694 break; 695 } 696 697 llvm::APSInt LoVal; 698 699 if (getLangOpts().CPlusPlus0x) { 700 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 701 // constant expression of the promoted type of the switch condition. 702 ExprResult ConvLo = 703 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue); 704 if (ConvLo.isInvalid()) { 705 CaseListIsErroneous = true; 706 continue; 707 } 708 Lo = ConvLo.take(); 709 } else { 710 // We already verified that the expression has a i-c-e value (C99 711 // 6.8.4.2p3) - get that value now. 712 LoVal = Lo->EvaluateKnownConstInt(Context); 713 714 // If the LHS is not the same type as the condition, insert an implicit 715 // cast. 716 Lo = DefaultLvalueConversion(Lo).take(); 717 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 718 } 719 720 // Convert the value to the same width/sign as the condition had prior to 721 // integral promotions. 722 // 723 // FIXME: This causes us to reject valid code: 724 // switch ((char)c) { case 256: case 0: return 0; } 725 // Here we claim there is a duplicated condition value, but there is not. 726 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 727 Lo->getLocStart(), 728 diag::warn_case_value_overflow); 729 730 CS->setLHS(Lo); 731 732 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 733 if (CS->getRHS()) { 734 if (CS->getRHS()->isTypeDependent() || 735 CS->getRHS()->isValueDependent()) { 736 HasDependentValue = true; 737 break; 738 } 739 CaseRanges.push_back(std::make_pair(LoVal, CS)); 740 } else 741 CaseVals.push_back(std::make_pair(LoVal, CS)); 742 } 743 } 744 745 if (!HasDependentValue) { 746 // If we don't have a default statement, check whether the 747 // condition is constant. 748 llvm::APSInt ConstantCondValue; 749 bool HasConstantCond = false; 750 if (!HasDependentValue && !TheDefaultStmt) { 751 HasConstantCond 752 = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context, 753 Expr::SE_AllowSideEffects); 754 assert(!HasConstantCond || 755 (ConstantCondValue.getBitWidth() == CondWidth && 756 ConstantCondValue.isSigned() == CondIsSigned)); 757 } 758 bool ShouldCheckConstantCond = HasConstantCond; 759 760 // Sort all the scalar case values so we can easily detect duplicates. 761 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 762 763 if (!CaseVals.empty()) { 764 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 765 if (ShouldCheckConstantCond && 766 CaseVals[i].first == ConstantCondValue) 767 ShouldCheckConstantCond = false; 768 769 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 770 // If we have a duplicate, report it. 771 Diag(CaseVals[i].second->getLHS()->getLocStart(), 772 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 773 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 774 diag::note_duplicate_case_prev); 775 // FIXME: We really want to remove the bogus case stmt from the 776 // substmt, but we have no way to do this right now. 777 CaseListIsErroneous = true; 778 } 779 } 780 } 781 782 // Detect duplicate case ranges, which usually don't exist at all in 783 // the first place. 784 if (!CaseRanges.empty()) { 785 // Sort all the case ranges by their low value so we can easily detect 786 // overlaps between ranges. 787 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 788 789 // Scan the ranges, computing the high values and removing empty ranges. 790 std::vector<llvm::APSInt> HiVals; 791 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 792 llvm::APSInt &LoVal = CaseRanges[i].first; 793 CaseStmt *CR = CaseRanges[i].second; 794 Expr *Hi = CR->getRHS(); 795 llvm::APSInt HiVal; 796 797 if (getLangOpts().CPlusPlus0x) { 798 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 799 // constant expression of the promoted type of the switch condition. 800 ExprResult ConvHi = 801 CheckConvertedConstantExpression(Hi, CondType, HiVal, 802 CCEK_CaseValue); 803 if (ConvHi.isInvalid()) { 804 CaseListIsErroneous = true; 805 continue; 806 } 807 Hi = ConvHi.take(); 808 } else { 809 HiVal = Hi->EvaluateKnownConstInt(Context); 810 811 // If the RHS is not the same type as the condition, insert an 812 // implicit cast. 813 Hi = DefaultLvalueConversion(Hi).take(); 814 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 815 } 816 817 // Convert the value to the same width/sign as the condition. 818 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 819 Hi->getLocStart(), 820 diag::warn_case_value_overflow); 821 822 CR->setRHS(Hi); 823 824 // If the low value is bigger than the high value, the case is empty. 825 if (LoVal > HiVal) { 826 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 827 << SourceRange(CR->getLHS()->getLocStart(), 828 Hi->getLocEnd()); 829 CaseRanges.erase(CaseRanges.begin()+i); 830 --i, --e; 831 continue; 832 } 833 834 if (ShouldCheckConstantCond && 835 LoVal <= ConstantCondValue && 836 ConstantCondValue <= HiVal) 837 ShouldCheckConstantCond = false; 838 839 HiVals.push_back(HiVal); 840 } 841 842 // Rescan the ranges, looking for overlap with singleton values and other 843 // ranges. Since the range list is sorted, we only need to compare case 844 // ranges with their neighbors. 845 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 846 llvm::APSInt &CRLo = CaseRanges[i].first; 847 llvm::APSInt &CRHi = HiVals[i]; 848 CaseStmt *CR = CaseRanges[i].second; 849 850 // Check to see whether the case range overlaps with any 851 // singleton cases. 852 CaseStmt *OverlapStmt = 0; 853 llvm::APSInt OverlapVal(32); 854 855 // Find the smallest value >= the lower bound. If I is in the 856 // case range, then we have overlap. 857 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 858 CaseVals.end(), CRLo, 859 CaseCompareFunctor()); 860 if (I != CaseVals.end() && I->first < CRHi) { 861 OverlapVal = I->first; // Found overlap with scalar. 862 OverlapStmt = I->second; 863 } 864 865 // Find the smallest value bigger than the upper bound. 866 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 867 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 868 OverlapVal = (I-1)->first; // Found overlap with scalar. 869 OverlapStmt = (I-1)->second; 870 } 871 872 // Check to see if this case stmt overlaps with the subsequent 873 // case range. 874 if (i && CRLo <= HiVals[i-1]) { 875 OverlapVal = HiVals[i-1]; // Found overlap with range. 876 OverlapStmt = CaseRanges[i-1].second; 877 } 878 879 if (OverlapStmt) { 880 // If we have a duplicate, report it. 881 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 882 << OverlapVal.toString(10); 883 Diag(OverlapStmt->getLHS()->getLocStart(), 884 diag::note_duplicate_case_prev); 885 // FIXME: We really want to remove the bogus case stmt from the 886 // substmt, but we have no way to do this right now. 887 CaseListIsErroneous = true; 888 } 889 } 890 } 891 892 // Complain if we have a constant condition and we didn't find a match. 893 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 894 // TODO: it would be nice if we printed enums as enums, chars as 895 // chars, etc. 896 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 897 << ConstantCondValue.toString(10) 898 << CondExpr->getSourceRange(); 899 } 900 901 // Check to see if switch is over an Enum and handles all of its 902 // values. We only issue a warning if there is not 'default:', but 903 // we still do the analysis to preserve this information in the AST 904 // (which can be used by flow-based analyes). 905 // 906 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 907 908 // If switch has default case, then ignore it. 909 if (!CaseListIsErroneous && !HasConstantCond && ET) { 910 const EnumDecl *ED = ET->getDecl(); 911 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 912 EnumValsTy; 913 EnumValsTy EnumVals; 914 915 // Gather all enum values, set their type and sort them, 916 // allowing easier comparison with CaseVals. 917 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 918 EDI != ED->enumerator_end(); ++EDI) { 919 llvm::APSInt Val = EDI->getInitVal(); 920 AdjustAPSInt(Val, CondWidth, CondIsSigned); 921 EnumVals.push_back(std::make_pair(Val, &*EDI)); 922 } 923 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 924 EnumValsTy::iterator EIend = 925 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 926 927 // See which case values aren't in enum. 928 EnumValsTy::const_iterator EI = EnumVals.begin(); 929 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 930 CI != CaseVals.end(); CI++) { 931 while (EI != EIend && EI->first < CI->first) 932 EI++; 933 if (EI == EIend || EI->first > CI->first) 934 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 935 << CondTypeBeforePromotion; 936 } 937 // See which of case ranges aren't in enum 938 EI = EnumVals.begin(); 939 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 940 RI != CaseRanges.end() && EI != EIend; RI++) { 941 while (EI != EIend && EI->first < RI->first) 942 EI++; 943 944 if (EI == EIend || EI->first != RI->first) { 945 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 946 << CondTypeBeforePromotion; 947 } 948 949 llvm::APSInt Hi = 950 RI->second->getRHS()->EvaluateKnownConstInt(Context); 951 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 952 while (EI != EIend && EI->first < Hi) 953 EI++; 954 if (EI == EIend || EI->first != Hi) 955 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 956 << CondTypeBeforePromotion; 957 } 958 959 // Check which enum vals aren't in switch 960 CaseValsTy::const_iterator CI = CaseVals.begin(); 961 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 962 bool hasCasesNotInSwitch = false; 963 964 SmallVector<DeclarationName,8> UnhandledNames; 965 966 for (EI = EnumVals.begin(); EI != EIend; EI++){ 967 // Drop unneeded case values 968 llvm::APSInt CIVal; 969 while (CI != CaseVals.end() && CI->first < EI->first) 970 CI++; 971 972 if (CI != CaseVals.end() && CI->first == EI->first) 973 continue; 974 975 // Drop unneeded case ranges 976 for (; RI != CaseRanges.end(); RI++) { 977 llvm::APSInt Hi = 978 RI->second->getRHS()->EvaluateKnownConstInt(Context); 979 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 980 if (EI->first <= Hi) 981 break; 982 } 983 984 if (RI == CaseRanges.end() || EI->first < RI->first) { 985 hasCasesNotInSwitch = true; 986 UnhandledNames.push_back(EI->second->getDeclName()); 987 } 988 } 989 990 if (TheDefaultStmt && UnhandledNames.empty()) 991 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default); 992 993 // Produce a nice diagnostic if multiple values aren't handled. 994 switch (UnhandledNames.size()) { 995 case 0: break; 996 case 1: 997 Diag(CondExpr->getExprLoc(), TheDefaultStmt 998 ? diag::warn_def_missing_case1 : diag::warn_missing_case1) 999 << UnhandledNames[0]; 1000 break; 1001 case 2: 1002 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1003 ? diag::warn_def_missing_case2 : diag::warn_missing_case2) 1004 << UnhandledNames[0] << UnhandledNames[1]; 1005 break; 1006 case 3: 1007 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1008 ? diag::warn_def_missing_case3 : diag::warn_missing_case3) 1009 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 1010 break; 1011 default: 1012 Diag(CondExpr->getExprLoc(), TheDefaultStmt 1013 ? diag::warn_def_missing_cases : diag::warn_missing_cases) 1014 << (unsigned)UnhandledNames.size() 1015 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 1016 break; 1017 } 1018 1019 if (!hasCasesNotInSwitch) 1020 SS->setAllEnumCasesCovered(); 1021 } 1022 } 1023 1024 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt, 1025 diag::warn_empty_switch_body); 1026 1027 // FIXME: If the case list was broken is some way, we don't have a good system 1028 // to patch it up. Instead, just return the whole substmt as broken. 1029 if (CaseListIsErroneous) 1030 return StmtError(); 1031 1032 return Owned(SS); 1033} 1034 1035StmtResult 1036Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 1037 Decl *CondVar, Stmt *Body) { 1038 ExprResult CondResult(Cond.release()); 1039 1040 VarDecl *ConditionVar = 0; 1041 if (CondVar) { 1042 ConditionVar = cast<VarDecl>(CondVar); 1043 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 1044 if (CondResult.isInvalid()) 1045 return StmtError(); 1046 } 1047 Expr *ConditionExpr = CondResult.take(); 1048 if (!ConditionExpr) 1049 return StmtError(); 1050 1051 DiagnoseUnusedExprResult(Body); 1052 1053 if (isa<NullStmt>(Body)) 1054 getCurCompoundScope().setHasEmptyLoopBodies(); 1055 1056 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 1057 Body, WhileLoc)); 1058} 1059 1060StmtResult 1061Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 1062 SourceLocation WhileLoc, SourceLocation CondLParen, 1063 Expr *Cond, SourceLocation CondRParen) { 1064 assert(Cond && "ActOnDoStmt(): missing expression"); 1065 1066 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 1067 if (CondResult.isInvalid() || CondResult.isInvalid()) 1068 return StmtError(); 1069 Cond = CondResult.take(); 1070 1071 CheckImplicitConversions(Cond, DoLoc); 1072 CondResult = MaybeCreateExprWithCleanups(Cond); 1073 if (CondResult.isInvalid()) 1074 return StmtError(); 1075 Cond = CondResult.take(); 1076 1077 DiagnoseUnusedExprResult(Body); 1078 1079 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 1080} 1081 1082namespace { 1083 // This visitor will traverse a conditional statement and store all 1084 // the evaluated decls into a vector. Simple is set to true if none 1085 // of the excluded constructs are used. 1086 class DeclExtractor : public EvaluatedExprVisitor<DeclExtractor> { 1087 llvm::SmallPtrSet<VarDecl*, 8> &Decls; 1088 llvm::SmallVector<SourceRange, 10> &Ranges; 1089 bool Simple; 1090 PartialDiagnostic &PDiag; 1091public: 1092 typedef EvaluatedExprVisitor<DeclExtractor> Inherited; 1093 1094 DeclExtractor(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, 1095 llvm::SmallVector<SourceRange, 10> &Ranges, 1096 PartialDiagnostic &PDiag) : 1097 Inherited(S.Context), 1098 Decls(Decls), 1099 Ranges(Ranges), 1100 Simple(true), 1101 PDiag(PDiag) {} 1102 1103 bool isSimple() { return Simple; } 1104 1105 // Replaces the method in EvaluatedExprVisitor. 1106 void VisitMemberExpr(MemberExpr* E) { 1107 Simple = false; 1108 } 1109 1110 // Any Stmt not whitelisted will cause the condition to be marked complex. 1111 void VisitStmt(Stmt *S) { 1112 Simple = false; 1113 } 1114 1115 void VisitBinaryOperator(BinaryOperator *E) { 1116 Visit(E->getLHS()); 1117 Visit(E->getRHS()); 1118 } 1119 1120 void VisitCastExpr(CastExpr *E) { 1121 Visit(E->getSubExpr()); 1122 } 1123 1124 void VisitUnaryOperator(UnaryOperator *E) { 1125 // Skip checking conditionals with derefernces. 1126 if (E->getOpcode() == UO_Deref) 1127 Simple = false; 1128 else 1129 Visit(E->getSubExpr()); 1130 } 1131 1132 void VisitConditionalOperator(ConditionalOperator *E) { 1133 Visit(E->getCond()); 1134 Visit(E->getTrueExpr()); 1135 Visit(E->getFalseExpr()); 1136 } 1137 1138 void VisitParenExpr(ParenExpr *E) { 1139 Visit(E->getSubExpr()); 1140 } 1141 1142 void VisitBinaryConditionalOperator(BinaryConditionalOperator *E) { 1143 Visit(E->getOpaqueValue()->getSourceExpr()); 1144 Visit(E->getFalseExpr()); 1145 } 1146 1147 void VisitIntegerLiteral(IntegerLiteral *E) { } 1148 void VisitFloatingLiteral(FloatingLiteral *E) { } 1149 void VisitCXXBoolLiteralExpr(CXXBoolLiteralExpr *E) { } 1150 void VisitCharacterLiteral(CharacterLiteral *E) { } 1151 void VisitGNUNullExpr(GNUNullExpr *E) { } 1152 void VisitImaginaryLiteral(ImaginaryLiteral *E) { } 1153 1154 void VisitDeclRefExpr(DeclRefExpr *E) { 1155 VarDecl *VD = dyn_cast<VarDecl>(E->getDecl()); 1156 if (!VD) return; 1157 1158 Ranges.push_back(E->getSourceRange()); 1159 1160 Decls.insert(VD); 1161 } 1162 1163 }; // end class DeclExtractor 1164 1165 // DeclMatcher checks to see if the decls are used in a non-evauluated 1166 // context. 1167 class DeclMatcher : public EvaluatedExprVisitor<DeclMatcher> { 1168 llvm::SmallPtrSet<VarDecl*, 8> &Decls; 1169 bool FoundDecl; 1170 //bool EvalDecl; 1171 1172public: 1173 typedef EvaluatedExprVisitor<DeclMatcher> Inherited; 1174 1175 DeclMatcher(Sema &S, llvm::SmallPtrSet<VarDecl*, 8> &Decls, Stmt *Statement) : 1176 Inherited(S.Context), Decls(Decls), FoundDecl(false) { 1177 if (!Statement) return; 1178 1179 Visit(Statement); 1180 } 1181 1182 void VisitReturnStmt(ReturnStmt *S) { 1183 FoundDecl = true; 1184 } 1185 1186 void VisitBreakStmt(BreakStmt *S) { 1187 FoundDecl = true; 1188 } 1189 1190 void VisitGotoStmt(GotoStmt *S) { 1191 FoundDecl = true; 1192 } 1193 1194 void VisitCastExpr(CastExpr *E) { 1195 if (E->getCastKind() == CK_LValueToRValue) 1196 CheckLValueToRValueCast(E->getSubExpr()); 1197 else 1198 Visit(E->getSubExpr()); 1199 } 1200 1201 void CheckLValueToRValueCast(Expr *E) { 1202 E = E->IgnoreParenImpCasts(); 1203 1204 if (isa<DeclRefExpr>(E)) { 1205 return; 1206 } 1207 1208 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 1209 Visit(CO->getCond()); 1210 CheckLValueToRValueCast(CO->getTrueExpr()); 1211 CheckLValueToRValueCast(CO->getFalseExpr()); 1212 return; 1213 } 1214 1215 if (BinaryConditionalOperator *BCO = 1216 dyn_cast<BinaryConditionalOperator>(E)) { 1217 CheckLValueToRValueCast(BCO->getOpaqueValue()->getSourceExpr()); 1218 CheckLValueToRValueCast(BCO->getFalseExpr()); 1219 return; 1220 } 1221 1222 Visit(E); 1223 } 1224 1225 void VisitDeclRefExpr(DeclRefExpr *E) { 1226 if (VarDecl *VD = dyn_cast<VarDecl>(E->getDecl())) 1227 if (Decls.count(VD)) 1228 FoundDecl = true; 1229 } 1230 1231 bool FoundDeclInUse() { return FoundDecl; } 1232 1233 }; // end class DeclMatcher 1234 1235 void CheckForLoopConditionalStatement(Sema &S, Expr *Second, 1236 Expr *Third, Stmt *Body) { 1237 // Condition is empty 1238 if (!Second) return; 1239 1240 if (S.Diags.getDiagnosticLevel(diag::warn_variables_not_in_loop_body, 1241 Second->getLocStart()) 1242 == DiagnosticsEngine::Ignored) 1243 return; 1244 1245 PartialDiagnostic PDiag = S.PDiag(diag::warn_variables_not_in_loop_body); 1246 llvm::SmallPtrSet<VarDecl*, 8> Decls; 1247 llvm::SmallVector<SourceRange, 10> Ranges; 1248 DeclExtractor DE(S, Decls, Ranges, PDiag); 1249 DE.Visit(Second); 1250 1251 // Don't analyze complex conditionals. 1252 if (!DE.isSimple()) return; 1253 1254 // No decls found. 1255 if (Decls.size() == 0) return; 1256 1257 // Don't warn on volatile, static, or global variables. 1258 for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(), 1259 E = Decls.end(); 1260 I != E; ++I) 1261 if ((*I)->getType().isVolatileQualified() || 1262 (*I)->hasGlobalStorage()) return; 1263 1264 if (DeclMatcher(S, Decls, Second).FoundDeclInUse() || 1265 DeclMatcher(S, Decls, Third).FoundDeclInUse() || 1266 DeclMatcher(S, Decls, Body).FoundDeclInUse()) 1267 return; 1268 1269 // Load decl names into diagnostic. 1270 if (Decls.size() > 4) 1271 PDiag << 0; 1272 else { 1273 PDiag << Decls.size(); 1274 for (llvm::SmallPtrSet<VarDecl*, 8>::iterator I = Decls.begin(), 1275 E = Decls.end(); 1276 I != E; ++I) 1277 PDiag << (*I)->getDeclName(); 1278 } 1279 1280 // Load SourceRanges into diagnostic if there is room. 1281 // Otherwise, load the SourceRange of the conditional expression. 1282 if (Ranges.size() <= PartialDiagnostic::MaxArguments) 1283 for (llvm::SmallVector<SourceRange, 10>::iterator I = Ranges.begin(), 1284 E = Ranges.end(); 1285 I != E; ++I) 1286 PDiag << *I; 1287 else 1288 PDiag << Second->getSourceRange(); 1289 1290 S.Diag(Ranges.begin()->getBegin(), PDiag); 1291 } 1292 1293} // end namespace 1294 1295StmtResult 1296Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1297 Stmt *First, FullExprArg second, Decl *secondVar, 1298 FullExprArg third, 1299 SourceLocation RParenLoc, Stmt *Body) { 1300 if (!getLangOpts().CPlusPlus) { 1301 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 1302 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1303 // declare identifiers for objects having storage class 'auto' or 1304 // 'register'. 1305 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 1306 DI!=DE; ++DI) { 1307 VarDecl *VD = dyn_cast<VarDecl>(*DI); 1308 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 1309 VD = 0; 1310 if (VD == 0) 1311 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 1312 // FIXME: mark decl erroneous! 1313 } 1314 } 1315 } 1316 1317 CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body); 1318 1319 ExprResult SecondResult(second.release()); 1320 VarDecl *ConditionVar = 0; 1321 if (secondVar) { 1322 ConditionVar = cast<VarDecl>(secondVar); 1323 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1324 if (SecondResult.isInvalid()) 1325 return StmtError(); 1326 } 1327 1328 Expr *Third = third.release().takeAs<Expr>(); 1329 1330 DiagnoseUnusedExprResult(First); 1331 DiagnoseUnusedExprResult(Third); 1332 DiagnoseUnusedExprResult(Body); 1333 1334 if (isa<NullStmt>(Body)) 1335 getCurCompoundScope().setHasEmptyLoopBodies(); 1336 1337 return Owned(new (Context) ForStmt(Context, First, 1338 SecondResult.take(), ConditionVar, 1339 Third, Body, ForLoc, LParenLoc, 1340 RParenLoc)); 1341} 1342 1343/// In an Objective C collection iteration statement: 1344/// for (x in y) 1345/// x can be an arbitrary l-value expression. Bind it up as a 1346/// full-expression. 1347StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1348 // Reduce placeholder expressions here. Note that this rejects the 1349 // use of pseudo-object l-values in this position. 1350 ExprResult result = CheckPlaceholderExpr(E); 1351 if (result.isInvalid()) return StmtError(); 1352 E = result.take(); 1353 1354 CheckImplicitConversions(E); 1355 1356 result = MaybeCreateExprWithCleanups(E); 1357 if (result.isInvalid()) return StmtError(); 1358 1359 return Owned(static_cast<Stmt*>(result.take())); 1360} 1361 1362ExprResult 1363Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1364 assert(collection); 1365 1366 // Bail out early if we've got a type-dependent expression. 1367 if (collection->isTypeDependent()) return Owned(collection); 1368 1369 // Perform normal l-value conversion. 1370 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1371 if (result.isInvalid()) 1372 return ExprError(); 1373 collection = result.take(); 1374 1375 // The operand needs to have object-pointer type. 1376 // TODO: should we do a contextual conversion? 1377 const ObjCObjectPointerType *pointerType = 1378 collection->getType()->getAs<ObjCObjectPointerType>(); 1379 if (!pointerType) 1380 return Diag(forLoc, diag::err_collection_expr_type) 1381 << collection->getType() << collection->getSourceRange(); 1382 1383 // Check that the operand provides 1384 // - countByEnumeratingWithState:objects:count: 1385 const ObjCObjectType *objectType = pointerType->getObjectType(); 1386 ObjCInterfaceDecl *iface = objectType->getInterface(); 1387 1388 // If we have a forward-declared type, we can't do this check. 1389 // Under ARC, it is an error not to have a forward-declared class. 1390 if (iface && 1391 RequireCompleteType(forLoc, QualType(objectType, 0), 1392 getLangOpts().ObjCAutoRefCount 1393 ? diag::err_arc_collection_forward 1394 : 0, 1395 collection)) { 1396 // Otherwise, if we have any useful type information, check that 1397 // the type declares the appropriate method. 1398 } else if (iface || !objectType->qual_empty()) { 1399 IdentifierInfo *selectorIdents[] = { 1400 &Context.Idents.get("countByEnumeratingWithState"), 1401 &Context.Idents.get("objects"), 1402 &Context.Idents.get("count") 1403 }; 1404 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1405 1406 ObjCMethodDecl *method = 0; 1407 1408 // If there's an interface, look in both the public and private APIs. 1409 if (iface) { 1410 method = iface->lookupInstanceMethod(selector); 1411 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1412 } 1413 1414 // Also check protocol qualifiers. 1415 if (!method) 1416 method = LookupMethodInQualifiedType(selector, pointerType, 1417 /*instance*/ true); 1418 1419 // If we didn't find it anywhere, give up. 1420 if (!method) { 1421 Diag(forLoc, diag::warn_collection_expr_type) 1422 << collection->getType() << selector << collection->getSourceRange(); 1423 } 1424 1425 // TODO: check for an incompatible signature? 1426 } 1427 1428 // Wrap up any cleanups in the expression. 1429 return Owned(MaybeCreateExprWithCleanups(collection)); 1430} 1431 1432StmtResult 1433Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1434 SourceLocation LParenLoc, 1435 Stmt *First, Expr *Second, 1436 SourceLocation RParenLoc, Stmt *Body) { 1437 if (First) { 1438 QualType FirstType; 1439 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1440 if (!DS->isSingleDecl()) 1441 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1442 diag::err_toomany_element_decls)); 1443 1444 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1445 FirstType = D->getType(); 1446 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1447 // declare identifiers for objects having storage class 'auto' or 1448 // 'register'. 1449 if (!D->hasLocalStorage()) 1450 return StmtError(Diag(D->getLocation(), 1451 diag::err_non_variable_decl_in_for)); 1452 } else { 1453 Expr *FirstE = cast<Expr>(First); 1454 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1455 return StmtError(Diag(First->getLocStart(), 1456 diag::err_selector_element_not_lvalue) 1457 << First->getSourceRange()); 1458 1459 FirstType = static_cast<Expr*>(First)->getType(); 1460 } 1461 if (!FirstType->isDependentType() && 1462 !FirstType->isObjCObjectPointerType() && 1463 !FirstType->isBlockPointerType()) 1464 Diag(ForLoc, diag::err_selector_element_type) 1465 << FirstType << First->getSourceRange(); 1466 } 1467 1468 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1469 ForLoc, RParenLoc)); 1470} 1471 1472namespace { 1473 1474enum BeginEndFunction { 1475 BEF_begin, 1476 BEF_end 1477}; 1478 1479/// Build a variable declaration for a for-range statement. 1480static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1481 QualType Type, const char *Name) { 1482 DeclContext *DC = SemaRef.CurContext; 1483 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1484 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1485 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1486 TInfo, SC_Auto, SC_None); 1487 Decl->setImplicit(); 1488 return Decl; 1489} 1490 1491/// Finish building a variable declaration for a for-range statement. 1492/// \return true if an error occurs. 1493static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1494 SourceLocation Loc, int diag) { 1495 // Deduce the type for the iterator variable now rather than leaving it to 1496 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1497 TypeSourceInfo *InitTSI = 0; 1498 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) || 1499 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) == 1500 Sema::DAR_Failed) 1501 SemaRef.Diag(Loc, diag) << Init->getType(); 1502 if (!InitTSI) { 1503 Decl->setInvalidDecl(); 1504 return true; 1505 } 1506 Decl->setTypeSourceInfo(InitTSI); 1507 Decl->setType(InitTSI->getType()); 1508 1509 // In ARC, infer lifetime. 1510 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1511 // we're doing the equivalent of fast iteration. 1512 if (SemaRef.getLangOpts().ObjCAutoRefCount && 1513 SemaRef.inferObjCARCLifetime(Decl)) 1514 Decl->setInvalidDecl(); 1515 1516 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1517 /*TypeMayContainAuto=*/false); 1518 SemaRef.FinalizeDeclaration(Decl); 1519 SemaRef.CurContext->addHiddenDecl(Decl); 1520 return false; 1521} 1522 1523/// Produce a note indicating which begin/end function was implicitly called 1524/// by a C++0x for-range statement. This is often not obvious from the code, 1525/// nor from the diagnostics produced when analysing the implicit expressions 1526/// required in a for-range statement. 1527void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1528 BeginEndFunction BEF) { 1529 CallExpr *CE = dyn_cast<CallExpr>(E); 1530 if (!CE) 1531 return; 1532 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1533 if (!D) 1534 return; 1535 SourceLocation Loc = D->getLocation(); 1536 1537 std::string Description; 1538 bool IsTemplate = false; 1539 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1540 Description = SemaRef.getTemplateArgumentBindingsText( 1541 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1542 IsTemplate = true; 1543 } 1544 1545 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1546 << BEF << IsTemplate << Description << E->getType(); 1547} 1548 1549/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1550/// given LookupResult is non-empty, it is assumed to describe a member which 1551/// will be invoked. Otherwise, the function will be found via argument 1552/// dependent lookup. 1553static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1554 SourceLocation Loc, 1555 VarDecl *Decl, 1556 BeginEndFunction BEF, 1557 const DeclarationNameInfo &NameInfo, 1558 LookupResult &MemberLookup, 1559 Expr *Range) { 1560 ExprResult CallExpr; 1561 if (!MemberLookup.empty()) { 1562 ExprResult MemberRef = 1563 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1564 /*IsPtr=*/false, CXXScopeSpec(), 1565 /*TemplateKWLoc=*/SourceLocation(), 1566 /*FirstQualifierInScope=*/0, 1567 MemberLookup, 1568 /*TemplateArgs=*/0); 1569 if (MemberRef.isInvalid()) 1570 return ExprError(); 1571 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1572 Loc, 0); 1573 if (CallExpr.isInvalid()) 1574 return ExprError(); 1575 } else { 1576 UnresolvedSet<0> FoundNames; 1577 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1578 // std is an associated namespace. 1579 UnresolvedLookupExpr *Fn = 1580 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1581 NestedNameSpecifierLoc(), NameInfo, 1582 /*NeedsADL=*/true, /*Overloaded=*/false, 1583 FoundNames.begin(), FoundNames.end(), 1584 /*LookInStdNamespace=*/true); 1585 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1586 0, /*AllowTypoCorrection=*/false); 1587 if (CallExpr.isInvalid()) { 1588 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1589 << Range->getType(); 1590 return ExprError(); 1591 } 1592 } 1593 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1594 diag::err_for_range_iter_deduction_failure)) { 1595 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1596 return ExprError(); 1597 } 1598 return CallExpr; 1599} 1600 1601} 1602 1603/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1604/// 1605/// C++0x [stmt.ranged]: 1606/// A range-based for statement is equivalent to 1607/// 1608/// { 1609/// auto && __range = range-init; 1610/// for ( auto __begin = begin-expr, 1611/// __end = end-expr; 1612/// __begin != __end; 1613/// ++__begin ) { 1614/// for-range-declaration = *__begin; 1615/// statement 1616/// } 1617/// } 1618/// 1619/// The body of the loop is not available yet, since it cannot be analysed until 1620/// we have determined the type of the for-range-declaration. 1621StmtResult 1622Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1623 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1624 SourceLocation RParenLoc) { 1625 if (!First || !Range) 1626 return StmtError(); 1627 1628 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1629 assert(DS && "first part of for range not a decl stmt"); 1630 1631 if (!DS->isSingleDecl()) { 1632 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1633 return StmtError(); 1634 } 1635 if (DS->getSingleDecl()->isInvalidDecl()) 1636 return StmtError(); 1637 1638 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1639 return StmtError(); 1640 1641 // Build auto && __range = range-init 1642 SourceLocation RangeLoc = Range->getLocStart(); 1643 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1644 Context.getAutoRRefDeductType(), 1645 "__range"); 1646 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1647 diag::err_for_range_deduction_failure)) 1648 return StmtError(); 1649 1650 // Claim the type doesn't contain auto: we've already done the checking. 1651 DeclGroupPtrTy RangeGroup = 1652 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1653 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1654 if (RangeDecl.isInvalid()) 1655 return StmtError(); 1656 1657 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1658 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1659 RParenLoc); 1660} 1661 1662/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1663StmtResult 1664Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1665 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1666 Expr *Inc, Stmt *LoopVarDecl, 1667 SourceLocation RParenLoc) { 1668 Scope *S = getCurScope(); 1669 1670 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1671 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1672 QualType RangeVarType = RangeVar->getType(); 1673 1674 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1675 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1676 1677 StmtResult BeginEndDecl = BeginEnd; 1678 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1679 1680 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1681 SourceLocation RangeLoc = RangeVar->getLocation(); 1682 1683 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1684 1685 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1686 VK_LValue, ColonLoc); 1687 if (BeginRangeRef.isInvalid()) 1688 return StmtError(); 1689 1690 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1691 VK_LValue, ColonLoc); 1692 if (EndRangeRef.isInvalid()) 1693 return StmtError(); 1694 1695 QualType AutoType = Context.getAutoDeductType(); 1696 Expr *Range = RangeVar->getInit(); 1697 if (!Range) 1698 return StmtError(); 1699 QualType RangeType = Range->getType(); 1700 1701 if (RequireCompleteType(RangeLoc, RangeType, 1702 diag::err_for_range_incomplete_type)) 1703 return StmtError(); 1704 1705 // Build auto __begin = begin-expr, __end = end-expr. 1706 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1707 "__begin"); 1708 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1709 "__end"); 1710 1711 // Build begin-expr and end-expr and attach to __begin and __end variables. 1712 ExprResult BeginExpr, EndExpr; 1713 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1714 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1715 // __range + __bound, respectively, where __bound is the array bound. If 1716 // _RangeT is an array of unknown size or an array of incomplete type, 1717 // the program is ill-formed; 1718 1719 // begin-expr is __range. 1720 BeginExpr = BeginRangeRef; 1721 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1722 diag::err_for_range_iter_deduction_failure)) { 1723 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1724 return StmtError(); 1725 } 1726 1727 // Find the array bound. 1728 ExprResult BoundExpr; 1729 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1730 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1731 Context.getPointerDiffType(), 1732 RangeLoc)); 1733 else if (const VariableArrayType *VAT = 1734 dyn_cast<VariableArrayType>(UnqAT)) 1735 BoundExpr = VAT->getSizeExpr(); 1736 else { 1737 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1738 // UnqAT is not incomplete and Range is not type-dependent. 1739 llvm_unreachable("Unexpected array type in for-range"); 1740 } 1741 1742 // end-expr is __range + __bound. 1743 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1744 BoundExpr.get()); 1745 if (EndExpr.isInvalid()) 1746 return StmtError(); 1747 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1748 diag::err_for_range_iter_deduction_failure)) { 1749 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1750 return StmtError(); 1751 } 1752 } else { 1753 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1754 ColonLoc); 1755 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1756 ColonLoc); 1757 1758 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1759 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1760 1761 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1762 // - if _RangeT is a class type, the unqualified-ids begin and end are 1763 // looked up in the scope of class _RangeT as if by class member access 1764 // lookup (3.4.5), and if either (or both) finds at least one 1765 // declaration, begin-expr and end-expr are __range.begin() and 1766 // __range.end(), respectively; 1767 LookupQualifiedName(BeginMemberLookup, D); 1768 LookupQualifiedName(EndMemberLookup, D); 1769 1770 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1771 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1772 << RangeType << BeginMemberLookup.empty(); 1773 return StmtError(); 1774 } 1775 } else { 1776 // - otherwise, begin-expr and end-expr are begin(__range) and 1777 // end(__range), respectively, where begin and end are looked up with 1778 // argument-dependent lookup (3.4.2). For the purposes of this name 1779 // lookup, namespace std is an associated namespace. 1780 } 1781 1782 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1783 BEF_begin, BeginNameInfo, 1784 BeginMemberLookup, 1785 BeginRangeRef.get()); 1786 if (BeginExpr.isInvalid()) 1787 return StmtError(); 1788 1789 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1790 BEF_end, EndNameInfo, 1791 EndMemberLookup, EndRangeRef.get()); 1792 if (EndExpr.isInvalid()) 1793 return StmtError(); 1794 } 1795 1796 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1797 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1798 if (!Context.hasSameType(BeginType, EndType)) { 1799 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1800 << BeginType << EndType; 1801 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1802 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1803 } 1804 1805 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1806 // Claim the type doesn't contain auto: we've already done the checking. 1807 DeclGroupPtrTy BeginEndGroup = 1808 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1809 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1810 1811 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1812 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1813 VK_LValue, ColonLoc); 1814 if (BeginRef.isInvalid()) 1815 return StmtError(); 1816 1817 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1818 VK_LValue, ColonLoc); 1819 if (EndRef.isInvalid()) 1820 return StmtError(); 1821 1822 // Build and check __begin != __end expression. 1823 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1824 BeginRef.get(), EndRef.get()); 1825 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1826 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1827 if (NotEqExpr.isInvalid()) { 1828 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1829 if (!Context.hasSameType(BeginType, EndType)) 1830 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1831 return StmtError(); 1832 } 1833 1834 // Build and check ++__begin expression. 1835 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1836 VK_LValue, ColonLoc); 1837 if (BeginRef.isInvalid()) 1838 return StmtError(); 1839 1840 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1841 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1842 if (IncrExpr.isInvalid()) { 1843 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1844 return StmtError(); 1845 } 1846 1847 // Build and check *__begin expression. 1848 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1849 VK_LValue, ColonLoc); 1850 if (BeginRef.isInvalid()) 1851 return StmtError(); 1852 1853 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1854 if (DerefExpr.isInvalid()) { 1855 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1856 return StmtError(); 1857 } 1858 1859 // Attach *__begin as initializer for VD. 1860 if (!LoopVar->isInvalidDecl()) { 1861 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1862 /*TypeMayContainAuto=*/true); 1863 if (LoopVar->isInvalidDecl()) 1864 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1865 } 1866 } else { 1867 // The range is implicitly used as a placeholder when it is dependent. 1868 RangeVar->setUsed(); 1869 } 1870 1871 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1872 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1873 NotEqExpr.take(), IncrExpr.take(), 1874 LoopVarDS, /*Body=*/0, ForLoc, 1875 ColonLoc, RParenLoc)); 1876} 1877 1878/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1879/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1880/// body cannot be performed until after the type of the range variable is 1881/// determined. 1882StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1883 if (!S || !B) 1884 return StmtError(); 1885 1886 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S); 1887 ForStmt->setBody(B); 1888 1889 DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B, 1890 diag::warn_empty_range_based_for_body); 1891 1892 return S; 1893} 1894 1895StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1896 SourceLocation LabelLoc, 1897 LabelDecl *TheDecl) { 1898 getCurFunction()->setHasBranchIntoScope(); 1899 TheDecl->setUsed(); 1900 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1901} 1902 1903StmtResult 1904Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1905 Expr *E) { 1906 // Convert operand to void* 1907 if (!E->isTypeDependent()) { 1908 QualType ETy = E->getType(); 1909 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1910 ExprResult ExprRes = Owned(E); 1911 AssignConvertType ConvTy = 1912 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1913 if (ExprRes.isInvalid()) 1914 return StmtError(); 1915 E = ExprRes.take(); 1916 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1917 return StmtError(); 1918 E = MaybeCreateExprWithCleanups(E); 1919 } 1920 1921 getCurFunction()->setHasIndirectGoto(); 1922 1923 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1924} 1925 1926StmtResult 1927Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1928 Scope *S = CurScope->getContinueParent(); 1929 if (!S) { 1930 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1931 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1932 } 1933 1934 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1935} 1936 1937StmtResult 1938Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1939 Scope *S = CurScope->getBreakParent(); 1940 if (!S) { 1941 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1942 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1943 } 1944 1945 return Owned(new (Context) BreakStmt(BreakLoc)); 1946} 1947 1948/// \brief Determine whether the given expression is a candidate for 1949/// copy elision in either a return statement or a throw expression. 1950/// 1951/// \param ReturnType If we're determining the copy elision candidate for 1952/// a return statement, this is the return type of the function. If we're 1953/// determining the copy elision candidate for a throw expression, this will 1954/// be a NULL type. 1955/// 1956/// \param E The expression being returned from the function or block, or 1957/// being thrown. 1958/// 1959/// \param AllowFunctionParameter Whether we allow function parameters to 1960/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1961/// we re-use this logic to determine whether we should try to move as part of 1962/// a return or throw (which does allow function parameters). 1963/// 1964/// \returns The NRVO candidate variable, if the return statement may use the 1965/// NRVO, or NULL if there is no such candidate. 1966const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1967 Expr *E, 1968 bool AllowFunctionParameter) { 1969 QualType ExprType = E->getType(); 1970 // - in a return statement in a function with ... 1971 // ... a class return type ... 1972 if (!ReturnType.isNull()) { 1973 if (!ReturnType->isRecordType()) 1974 return 0; 1975 // ... the same cv-unqualified type as the function return type ... 1976 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1977 return 0; 1978 } 1979 1980 // ... the expression is the name of a non-volatile automatic object 1981 // (other than a function or catch-clause parameter)) ... 1982 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1983 if (!DR) 1984 return 0; 1985 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1986 if (!VD) 1987 return 0; 1988 1989 // ...object (other than a function or catch-clause parameter)... 1990 if (VD->getKind() != Decl::Var && 1991 !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) 1992 return 0; 1993 if (VD->isExceptionVariable()) return 0; 1994 1995 // ...automatic... 1996 if (!VD->hasLocalStorage()) return 0; 1997 1998 // ...non-volatile... 1999 if (VD->getType().isVolatileQualified()) return 0; 2000 if (VD->getType()->isReferenceType()) return 0; 2001 2002 // __block variables can't be allocated in a way that permits NRVO. 2003 if (VD->hasAttr<BlocksAttr>()) return 0; 2004 2005 // Variables with higher required alignment than their type's ABI 2006 // alignment cannot use NRVO. 2007 if (VD->hasAttr<AlignedAttr>() && 2008 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) 2009 return 0; 2010 2011 return VD; 2012} 2013 2014/// \brief Perform the initialization of a potentially-movable value, which 2015/// is the result of return value. 2016/// 2017/// This routine implements C++0x [class.copy]p33, which attempts to treat 2018/// returned lvalues as rvalues in certain cases (to prefer move construction), 2019/// then falls back to treating them as lvalues if that failed. 2020ExprResult 2021Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 2022 const VarDecl *NRVOCandidate, 2023 QualType ResultType, 2024 Expr *Value, 2025 bool AllowNRVO) { 2026 // C++0x [class.copy]p33: 2027 // When the criteria for elision of a copy operation are met or would 2028 // be met save for the fact that the source object is a function 2029 // parameter, and the object to be copied is designated by an lvalue, 2030 // overload resolution to select the constructor for the copy is first 2031 // performed as if the object were designated by an rvalue. 2032 ExprResult Res = ExprError(); 2033 if (AllowNRVO && 2034 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 2035 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 2036 Value->getType(), CK_LValueToRValue, 2037 Value, VK_XValue); 2038 2039 Expr *InitExpr = &AsRvalue; 2040 InitializationKind Kind 2041 = InitializationKind::CreateCopy(Value->getLocStart(), 2042 Value->getLocStart()); 2043 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 2044 2045 // [...] If overload resolution fails, or if the type of the first 2046 // parameter of the selected constructor is not an rvalue reference 2047 // to the object's type (possibly cv-qualified), overload resolution 2048 // is performed again, considering the object as an lvalue. 2049 if (Seq) { 2050 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 2051 StepEnd = Seq.step_end(); 2052 Step != StepEnd; ++Step) { 2053 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 2054 continue; 2055 2056 CXXConstructorDecl *Constructor 2057 = cast<CXXConstructorDecl>(Step->Function.Function); 2058 2059 const RValueReferenceType *RRefType 2060 = Constructor->getParamDecl(0)->getType() 2061 ->getAs<RValueReferenceType>(); 2062 2063 // If we don't meet the criteria, break out now. 2064 if (!RRefType || 2065 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 2066 Context.getTypeDeclType(Constructor->getParent()))) 2067 break; 2068 2069 // Promote "AsRvalue" to the heap, since we now need this 2070 // expression node to persist. 2071 Value = ImplicitCastExpr::Create(Context, Value->getType(), 2072 CK_LValueToRValue, Value, 0, 2073 VK_XValue); 2074 2075 // Complete type-checking the initialization of the return type 2076 // using the constructor we found. 2077 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 2078 } 2079 } 2080 } 2081 2082 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 2083 // above, or overload resolution failed. Either way, we need to try 2084 // (again) now with the return value expression as written. 2085 if (Res.isInvalid()) 2086 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 2087 2088 return Res; 2089} 2090 2091/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements 2092/// for capturing scopes. 2093/// 2094StmtResult 2095Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 2096 // If this is the first return we've seen, infer the return type. 2097 // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those 2098 // rules which allows multiple return statements. 2099 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction()); 2100 if (CurCap->HasImplicitReturnType) { 2101 QualType ReturnT; 2102 if (RetValExp && !isa<InitListExpr>(RetValExp)) { 2103 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 2104 if (Result.isInvalid()) 2105 return StmtError(); 2106 RetValExp = Result.take(); 2107 2108 if (!RetValExp->isTypeDependent()) 2109 ReturnT = RetValExp->getType(); 2110 else 2111 ReturnT = Context.DependentTy; 2112 } else { 2113 if (RetValExp) { 2114 // C++11 [expr.lambda.prim]p4 bans inferring the result from an 2115 // initializer list, because it is not an expression (even 2116 // though we represent it as one). We still deduce 'void'. 2117 Diag(ReturnLoc, diag::err_lambda_return_init_list) 2118 << RetValExp->getSourceRange(); 2119 } 2120 2121 ReturnT = Context.VoidTy; 2122 } 2123 // We require the return types to strictly match here. 2124 if (!CurCap->ReturnType.isNull() && 2125 !CurCap->ReturnType->isDependentType() && 2126 !ReturnT->isDependentType() && 2127 !Context.hasSameType(ReturnT, CurCap->ReturnType)) { 2128 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) 2129 << ReturnT << CurCap->ReturnType 2130 << (getCurLambda() != 0); 2131 return StmtError(); 2132 } 2133 CurCap->ReturnType = ReturnT; 2134 } 2135 QualType FnRetType = CurCap->ReturnType; 2136 assert(!FnRetType.isNull()); 2137 2138 if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) { 2139 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 2140 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr); 2141 return StmtError(); 2142 } 2143 } else { 2144 LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CurCap); 2145 if (LSI->CallOperator->getType()->getAs<FunctionType>()->getNoReturnAttr()){ 2146 Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr); 2147 return StmtError(); 2148 } 2149 } 2150 2151 // Otherwise, verify that this result type matches the previous one. We are 2152 // pickier with blocks than for normal functions because we don't have GCC 2153 // compatibility to worry about here. 2154 const VarDecl *NRVOCandidate = 0; 2155 if (FnRetType->isDependentType()) { 2156 // Delay processing for now. TODO: there are lots of dependent 2157 // types we can conclusively prove aren't void. 2158 } else if (FnRetType->isVoidType()) { 2159 if (RetValExp && !isa<InitListExpr>(RetValExp) && 2160 !(getLangOpts().CPlusPlus && 2161 (RetValExp->isTypeDependent() || 2162 RetValExp->getType()->isVoidType()))) { 2163 if (!getLangOpts().CPlusPlus && 2164 RetValExp->getType()->isVoidType()) 2165 Diag(ReturnLoc, diag::ext_return_has_void_expr) << "literal" << 2; 2166 else { 2167 Diag(ReturnLoc, diag::err_return_block_has_expr); 2168 RetValExp = 0; 2169 } 2170 } 2171 } else if (!RetValExp) { 2172 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 2173 } else if (!RetValExp->isTypeDependent()) { 2174 // we have a non-void block with an expression, continue checking 2175 2176 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2177 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2178 // function return. 2179 2180 // In C++ the return statement is handled via a copy initialization. 2181 // the C version of which boils down to CheckSingleAssignmentConstraints. 2182 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2183 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2184 FnRetType, 2185 NRVOCandidate != 0); 2186 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2187 FnRetType, RetValExp); 2188 if (Res.isInvalid()) { 2189 // FIXME: Cleanup temporaries here, anyway? 2190 return StmtError(); 2191 } 2192 RetValExp = Res.take(); 2193 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2194 } 2195 2196 if (RetValExp) { 2197 CheckImplicitConversions(RetValExp, ReturnLoc); 2198 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2199 } 2200 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 2201 NRVOCandidate); 2202 2203 // If we need to check for the named return value optimization, save the 2204 // return statement in our scope for later processing. 2205 if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 2206 !CurContext->isDependentContext()) 2207 FunctionScopes.back()->Returns.push_back(Result); 2208 2209 return Owned(Result); 2210} 2211 2212StmtResult 2213Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 2214 // Check for unexpanded parameter packs. 2215 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 2216 return StmtError(); 2217 2218 if (isa<CapturingScopeInfo>(getCurFunction())) 2219 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp); 2220 2221 QualType FnRetType; 2222 QualType RelatedRetType; 2223 if (const FunctionDecl *FD = getCurFunctionDecl()) { 2224 FnRetType = FD->getResultType(); 2225 if (FD->hasAttr<NoReturnAttr>() || 2226 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 2227 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 2228 << FD->getDeclName(); 2229 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 2230 FnRetType = MD->getResultType(); 2231 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 2232 // In the implementation of a method with a related return type, the 2233 // type used to type-check the validity of return statements within the 2234 // method body is a pointer to the type of the class being implemented. 2235 RelatedRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 2236 RelatedRetType = Context.getObjCObjectPointerType(RelatedRetType); 2237 } 2238 } else // If we don't have a function/method context, bail. 2239 return StmtError(); 2240 2241 ReturnStmt *Result = 0; 2242 if (FnRetType->isVoidType()) { 2243 if (RetValExp) { 2244 if (isa<InitListExpr>(RetValExp)) { 2245 // We simply never allow init lists as the return value of void 2246 // functions. This is compatible because this was never allowed before, 2247 // so there's no legacy code to deal with. 2248 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2249 int FunctionKind = 0; 2250 if (isa<ObjCMethodDecl>(CurDecl)) 2251 FunctionKind = 1; 2252 else if (isa<CXXConstructorDecl>(CurDecl)) 2253 FunctionKind = 2; 2254 else if (isa<CXXDestructorDecl>(CurDecl)) 2255 FunctionKind = 3; 2256 2257 Diag(ReturnLoc, diag::err_return_init_list) 2258 << CurDecl->getDeclName() << FunctionKind 2259 << RetValExp->getSourceRange(); 2260 2261 // Drop the expression. 2262 RetValExp = 0; 2263 } else if (!RetValExp->isTypeDependent()) { 2264 // C99 6.8.6.4p1 (ext_ since GCC warns) 2265 unsigned D = diag::ext_return_has_expr; 2266 if (RetValExp->getType()->isVoidType()) 2267 D = diag::ext_return_has_void_expr; 2268 else { 2269 ExprResult Result = Owned(RetValExp); 2270 Result = IgnoredValueConversions(Result.take()); 2271 if (Result.isInvalid()) 2272 return StmtError(); 2273 RetValExp = Result.take(); 2274 RetValExp = ImpCastExprToType(RetValExp, 2275 Context.VoidTy, CK_ToVoid).take(); 2276 } 2277 2278 // return (some void expression); is legal in C++. 2279 if (D != diag::ext_return_has_void_expr || 2280 !getLangOpts().CPlusPlus) { 2281 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2282 2283 int FunctionKind = 0; 2284 if (isa<ObjCMethodDecl>(CurDecl)) 2285 FunctionKind = 1; 2286 else if (isa<CXXConstructorDecl>(CurDecl)) 2287 FunctionKind = 2; 2288 else if (isa<CXXDestructorDecl>(CurDecl)) 2289 FunctionKind = 3; 2290 2291 Diag(ReturnLoc, D) 2292 << CurDecl->getDeclName() << FunctionKind 2293 << RetValExp->getSourceRange(); 2294 } 2295 } 2296 2297 if (RetValExp) { 2298 CheckImplicitConversions(RetValExp, ReturnLoc); 2299 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2300 } 2301 } 2302 2303 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 2304 } else if (!RetValExp && !FnRetType->isDependentType()) { 2305 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 2306 // C99 6.8.6.4p1 (ext_ since GCC warns) 2307 if (getLangOpts().C99) DiagID = diag::ext_return_missing_expr; 2308 2309 if (FunctionDecl *FD = getCurFunctionDecl()) 2310 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 2311 else 2312 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 2313 Result = new (Context) ReturnStmt(ReturnLoc); 2314 } else { 2315 const VarDecl *NRVOCandidate = 0; 2316 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 2317 // we have a non-void function with an expression, continue checking 2318 2319 if (!RelatedRetType.isNull()) { 2320 // If we have a related result type, perform an extra conversion here. 2321 // FIXME: The diagnostics here don't really describe what is happening. 2322 InitializedEntity Entity = 2323 InitializedEntity::InitializeTemporary(RelatedRetType); 2324 2325 ExprResult Res = PerformCopyInitialization(Entity, SourceLocation(), 2326 RetValExp); 2327 if (Res.isInvalid()) { 2328 // FIXME: Cleanup temporaries here, anyway? 2329 return StmtError(); 2330 } 2331 RetValExp = Res.takeAs<Expr>(); 2332 } 2333 2334 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2335 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2336 // function return. 2337 2338 // In C++ the return statement is handled via a copy initialization, 2339 // the C version of which boils down to CheckSingleAssignmentConstraints. 2340 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2341 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2342 FnRetType, 2343 NRVOCandidate != 0); 2344 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2345 FnRetType, RetValExp); 2346 if (Res.isInvalid()) { 2347 // FIXME: Cleanup temporaries here, anyway? 2348 return StmtError(); 2349 } 2350 2351 RetValExp = Res.takeAs<Expr>(); 2352 if (RetValExp) 2353 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2354 } 2355 2356 if (RetValExp) { 2357 CheckImplicitConversions(RetValExp, ReturnLoc); 2358 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2359 } 2360 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 2361 } 2362 2363 // If we need to check for the named return value optimization, save the 2364 // return statement in our scope for later processing. 2365 if (getLangOpts().CPlusPlus && FnRetType->isRecordType() && 2366 !CurContext->isDependentContext()) 2367 FunctionScopes.back()->Returns.push_back(Result); 2368 2369 return Owned(Result); 2370} 2371 2372/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 2373/// ignore "noop" casts in places where an lvalue is required by an inline asm. 2374/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 2375/// provide a strong guidance to not use it. 2376/// 2377/// This method checks to see if the argument is an acceptable l-value and 2378/// returns false if it is a case we can handle. 2379static bool CheckAsmLValue(const Expr *E, Sema &S) { 2380 // Type dependent expressions will be checked during instantiation. 2381 if (E->isTypeDependent()) 2382 return false; 2383 2384 if (E->isLValue()) 2385 return false; // Cool, this is an lvalue. 2386 2387 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 2388 // are supposed to allow. 2389 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 2390 if (E != E2 && E2->isLValue()) { 2391 if (!S.getLangOpts().HeinousExtensions) 2392 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 2393 << E->getSourceRange(); 2394 else 2395 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 2396 << E->getSourceRange(); 2397 // Accept, even if we emitted an error diagnostic. 2398 return false; 2399 } 2400 2401 // None of the above, just randomly invalid non-lvalue. 2402 return true; 2403} 2404 2405/// isOperandMentioned - Return true if the specified operand # is mentioned 2406/// anywhere in the decomposed asm string. 2407static bool isOperandMentioned(unsigned OpNo, 2408 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2409 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2410 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2411 if (!Piece.isOperand()) continue; 2412 2413 // If this is a reference to the input and if the input was the smaller 2414 // one, then we have to reject this asm. 2415 if (Piece.getOperandNo() == OpNo) 2416 return true; 2417 } 2418 2419 return false; 2420} 2421 2422StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2423 bool IsVolatile, unsigned NumOutputs, 2424 unsigned NumInputs, IdentifierInfo **Names, 2425 MultiExprArg constraints, MultiExprArg exprs, 2426 Expr *asmString, MultiExprArg clobbers, 2427 SourceLocation RParenLoc, bool MSAsm) { 2428 unsigned NumClobbers = clobbers.size(); 2429 StringLiteral **Constraints = 2430 reinterpret_cast<StringLiteral**>(constraints.get()); 2431 Expr **Exprs = exprs.get(); 2432 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2433 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2434 2435 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2436 2437 // The parser verifies that there is a string literal here. 2438 if (!AsmString->isAscii()) 2439 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2440 << AsmString->getSourceRange()); 2441 2442 for (unsigned i = 0; i != NumOutputs; i++) { 2443 StringLiteral *Literal = Constraints[i]; 2444 if (!Literal->isAscii()) 2445 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2446 << Literal->getSourceRange()); 2447 2448 StringRef OutputName; 2449 if (Names[i]) 2450 OutputName = Names[i]->getName(); 2451 2452 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2453 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2454 return StmtError(Diag(Literal->getLocStart(), 2455 diag::err_asm_invalid_output_constraint) 2456 << Info.getConstraintStr()); 2457 2458 // Check that the output exprs are valid lvalues. 2459 Expr *OutputExpr = Exprs[i]; 2460 if (CheckAsmLValue(OutputExpr, *this)) { 2461 return StmtError(Diag(OutputExpr->getLocStart(), 2462 diag::err_asm_invalid_lvalue_in_output) 2463 << OutputExpr->getSourceRange()); 2464 } 2465 2466 OutputConstraintInfos.push_back(Info); 2467 } 2468 2469 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2470 2471 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2472 StringLiteral *Literal = Constraints[i]; 2473 if (!Literal->isAscii()) 2474 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2475 << Literal->getSourceRange()); 2476 2477 StringRef InputName; 2478 if (Names[i]) 2479 InputName = Names[i]->getName(); 2480 2481 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2482 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2483 NumOutputs, Info)) { 2484 return StmtError(Diag(Literal->getLocStart(), 2485 diag::err_asm_invalid_input_constraint) 2486 << Info.getConstraintStr()); 2487 } 2488 2489 Expr *InputExpr = Exprs[i]; 2490 2491 // Only allow void types for memory constraints. 2492 if (Info.allowsMemory() && !Info.allowsRegister()) { 2493 if (CheckAsmLValue(InputExpr, *this)) 2494 return StmtError(Diag(InputExpr->getLocStart(), 2495 diag::err_asm_invalid_lvalue_in_input) 2496 << Info.getConstraintStr() 2497 << InputExpr->getSourceRange()); 2498 } 2499 2500 if (Info.allowsRegister()) { 2501 if (InputExpr->getType()->isVoidType()) { 2502 return StmtError(Diag(InputExpr->getLocStart(), 2503 diag::err_asm_invalid_type_in_input) 2504 << InputExpr->getType() << Info.getConstraintStr() 2505 << InputExpr->getSourceRange()); 2506 } 2507 } 2508 2509 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2510 if (Result.isInvalid()) 2511 return StmtError(); 2512 2513 Exprs[i] = Result.take(); 2514 InputConstraintInfos.push_back(Info); 2515 } 2516 2517 // Check that the clobbers are valid. 2518 for (unsigned i = 0; i != NumClobbers; i++) { 2519 StringLiteral *Literal = Clobbers[i]; 2520 if (!Literal->isAscii()) 2521 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2522 << Literal->getSourceRange()); 2523 2524 StringRef Clobber = Literal->getString(); 2525 2526 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2527 return StmtError(Diag(Literal->getLocStart(), 2528 diag::err_asm_unknown_register_name) << Clobber); 2529 } 2530 2531 AsmStmt *NS = 2532 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2533 NumOutputs, NumInputs, Names, Constraints, Exprs, 2534 AsmString, NumClobbers, Clobbers, RParenLoc); 2535 // Validate the asm string, ensuring it makes sense given the operands we 2536 // have. 2537 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2538 unsigned DiagOffs; 2539 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2540 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2541 << AsmString->getSourceRange(); 2542 return StmtError(); 2543 } 2544 2545 // Validate tied input operands for type mismatches. 2546 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2547 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2548 2549 // If this is a tied constraint, verify that the output and input have 2550 // either exactly the same type, or that they are int/ptr operands with the 2551 // same size (int/long, int*/long, are ok etc). 2552 if (!Info.hasTiedOperand()) continue; 2553 2554 unsigned TiedTo = Info.getTiedOperand(); 2555 unsigned InputOpNo = i+NumOutputs; 2556 Expr *OutputExpr = Exprs[TiedTo]; 2557 Expr *InputExpr = Exprs[InputOpNo]; 2558 2559 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2560 continue; 2561 2562 QualType InTy = InputExpr->getType(); 2563 QualType OutTy = OutputExpr->getType(); 2564 if (Context.hasSameType(InTy, OutTy)) 2565 continue; // All types can be tied to themselves. 2566 2567 // Decide if the input and output are in the same domain (integer/ptr or 2568 // floating point. 2569 enum AsmDomain { 2570 AD_Int, AD_FP, AD_Other 2571 } InputDomain, OutputDomain; 2572 2573 if (InTy->isIntegerType() || InTy->isPointerType()) 2574 InputDomain = AD_Int; 2575 else if (InTy->isRealFloatingType()) 2576 InputDomain = AD_FP; 2577 else 2578 InputDomain = AD_Other; 2579 2580 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2581 OutputDomain = AD_Int; 2582 else if (OutTy->isRealFloatingType()) 2583 OutputDomain = AD_FP; 2584 else 2585 OutputDomain = AD_Other; 2586 2587 // They are ok if they are the same size and in the same domain. This 2588 // allows tying things like: 2589 // void* to int* 2590 // void* to int if they are the same size. 2591 // double to long double if they are the same size. 2592 // 2593 uint64_t OutSize = Context.getTypeSize(OutTy); 2594 uint64_t InSize = Context.getTypeSize(InTy); 2595 if (OutSize == InSize && InputDomain == OutputDomain && 2596 InputDomain != AD_Other) 2597 continue; 2598 2599 // If the smaller input/output operand is not mentioned in the asm string, 2600 // then we can promote the smaller one to a larger input and the asm string 2601 // won't notice. 2602 bool SmallerValueMentioned = false; 2603 2604 // If this is a reference to the input and if the input was the smaller 2605 // one, then we have to reject this asm. 2606 if (isOperandMentioned(InputOpNo, Pieces)) { 2607 // This is a use in the asm string of the smaller operand. Since we 2608 // codegen this by promoting to a wider value, the asm will get printed 2609 // "wrong". 2610 SmallerValueMentioned |= InSize < OutSize; 2611 } 2612 if (isOperandMentioned(TiedTo, Pieces)) { 2613 // If this is a reference to the output, and if the output is the larger 2614 // value, then it's ok because we'll promote the input to the larger type. 2615 SmallerValueMentioned |= OutSize < InSize; 2616 } 2617 2618 // If the smaller value wasn't mentioned in the asm string, and if the 2619 // output was a register, just extend the shorter one to the size of the 2620 // larger one. 2621 if (!SmallerValueMentioned && InputDomain != AD_Other && 2622 OutputConstraintInfos[TiedTo].allowsRegister()) 2623 continue; 2624 2625 // Either both of the operands were mentioned or the smaller one was 2626 // mentioned. One more special case that we'll allow: if the tied input is 2627 // integer, unmentioned, and is a constant, then we'll allow truncating it 2628 // down to the size of the destination. 2629 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2630 !isOperandMentioned(InputOpNo, Pieces) && 2631 InputExpr->isEvaluatable(Context)) { 2632 CastKind castKind = 2633 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2634 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2635 Exprs[InputOpNo] = InputExpr; 2636 NS->setInputExpr(i, InputExpr); 2637 continue; 2638 } 2639 2640 Diag(InputExpr->getLocStart(), 2641 diag::err_asm_tying_incompatible_types) 2642 << InTy << OutTy << OutputExpr->getSourceRange() 2643 << InputExpr->getSourceRange(); 2644 return StmtError(); 2645 } 2646 2647 return Owned(NS); 2648} 2649 2650StmtResult 2651Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2652 SourceLocation RParen, Decl *Parm, 2653 Stmt *Body) { 2654 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2655 if (Var && Var->isInvalidDecl()) 2656 return StmtError(); 2657 2658 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2659} 2660 2661StmtResult 2662Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2663 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2664} 2665 2666StmtResult 2667Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2668 MultiStmtArg CatchStmts, Stmt *Finally) { 2669 if (!getLangOpts().ObjCExceptions) 2670 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2671 2672 getCurFunction()->setHasBranchProtectedScope(); 2673 unsigned NumCatchStmts = CatchStmts.size(); 2674 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2675 CatchStmts.release(), 2676 NumCatchStmts, 2677 Finally)); 2678} 2679 2680StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) { 2681 if (Throw) { 2682 ExprResult Result = DefaultLvalueConversion(Throw); 2683 if (Result.isInvalid()) 2684 return StmtError(); 2685 2686 Throw = MaybeCreateExprWithCleanups(Result.take()); 2687 QualType ThrowType = Throw->getType(); 2688 // Make sure the expression type is an ObjC pointer or "void *". 2689 if (!ThrowType->isDependentType() && 2690 !ThrowType->isObjCObjectPointerType()) { 2691 const PointerType *PT = ThrowType->getAs<PointerType>(); 2692 if (!PT || !PT->getPointeeType()->isVoidType()) 2693 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2694 << Throw->getType() << Throw->getSourceRange()); 2695 } 2696 } 2697 2698 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2699} 2700 2701StmtResult 2702Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2703 Scope *CurScope) { 2704 if (!getLangOpts().ObjCExceptions) 2705 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2706 2707 if (!Throw) { 2708 // @throw without an expression designates a rethrow (which much occur 2709 // in the context of an @catch clause). 2710 Scope *AtCatchParent = CurScope; 2711 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2712 AtCatchParent = AtCatchParent->getParent(); 2713 if (!AtCatchParent) 2714 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2715 } 2716 2717 return BuildObjCAtThrowStmt(AtLoc, Throw); 2718} 2719 2720ExprResult 2721Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 2722 ExprResult result = DefaultLvalueConversion(operand); 2723 if (result.isInvalid()) 2724 return ExprError(); 2725 operand = result.take(); 2726 2727 // Make sure the expression type is an ObjC pointer or "void *". 2728 QualType type = operand->getType(); 2729 if (!type->isDependentType() && 2730 !type->isObjCObjectPointerType()) { 2731 const PointerType *pointerType = type->getAs<PointerType>(); 2732 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 2733 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 2734 << type << operand->getSourceRange(); 2735 } 2736 2737 // The operand to @synchronized is a full-expression. 2738 return MaybeCreateExprWithCleanups(operand); 2739} 2740 2741StmtResult 2742Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2743 Stmt *SyncBody) { 2744 // We can't jump into or indirect-jump out of a @synchronized block. 2745 getCurFunction()->setHasBranchProtectedScope(); 2746 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2747} 2748 2749/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2750/// and creates a proper catch handler from them. 2751StmtResult 2752Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2753 Stmt *HandlerBlock) { 2754 // There's nothing to test that ActOnExceptionDecl didn't already test. 2755 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2756 cast_or_null<VarDecl>(ExDecl), 2757 HandlerBlock)); 2758} 2759 2760StmtResult 2761Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2762 getCurFunction()->setHasBranchProtectedScope(); 2763 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2764} 2765 2766namespace { 2767 2768class TypeWithHandler { 2769 QualType t; 2770 CXXCatchStmt *stmt; 2771public: 2772 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2773 : t(type), stmt(statement) {} 2774 2775 // An arbitrary order is fine as long as it places identical 2776 // types next to each other. 2777 bool operator<(const TypeWithHandler &y) const { 2778 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2779 return true; 2780 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2781 return false; 2782 else 2783 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2784 } 2785 2786 bool operator==(const TypeWithHandler& other) const { 2787 return t == other.t; 2788 } 2789 2790 CXXCatchStmt *getCatchStmt() const { return stmt; } 2791 SourceLocation getTypeSpecStartLoc() const { 2792 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2793 } 2794}; 2795 2796} 2797 2798/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2799/// handlers and creates a try statement from them. 2800StmtResult 2801Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2802 MultiStmtArg RawHandlers) { 2803 // Don't report an error if 'try' is used in system headers. 2804 if (!getLangOpts().CXXExceptions && 2805 !getSourceManager().isInSystemHeader(TryLoc)) 2806 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2807 2808 unsigned NumHandlers = RawHandlers.size(); 2809 assert(NumHandlers > 0 && 2810 "The parser shouldn't call this if there are no handlers."); 2811 Stmt **Handlers = RawHandlers.get(); 2812 2813 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2814 2815 for (unsigned i = 0; i < NumHandlers; ++i) { 2816 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2817 if (!Handler->getExceptionDecl()) { 2818 if (i < NumHandlers - 1) 2819 return StmtError(Diag(Handler->getLocStart(), 2820 diag::err_early_catch_all)); 2821 2822 continue; 2823 } 2824 2825 const QualType CaughtType = Handler->getCaughtType(); 2826 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2827 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2828 } 2829 2830 // Detect handlers for the same type as an earlier one. 2831 if (NumHandlers > 1) { 2832 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2833 2834 TypeWithHandler prev = TypesWithHandlers[0]; 2835 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2836 TypeWithHandler curr = TypesWithHandlers[i]; 2837 2838 if (curr == prev) { 2839 Diag(curr.getTypeSpecStartLoc(), 2840 diag::warn_exception_caught_by_earlier_handler) 2841 << curr.getCatchStmt()->getCaughtType().getAsString(); 2842 Diag(prev.getTypeSpecStartLoc(), 2843 diag::note_previous_exception_handler) 2844 << prev.getCatchStmt()->getCaughtType().getAsString(); 2845 } 2846 2847 prev = curr; 2848 } 2849 } 2850 2851 getCurFunction()->setHasBranchProtectedScope(); 2852 2853 // FIXME: We should detect handlers that cannot catch anything because an 2854 // earlier handler catches a superclass. Need to find a method that is not 2855 // quadratic for this. 2856 // Neither of these are explicitly forbidden, but every compiler detects them 2857 // and warns. 2858 2859 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2860 Handlers, NumHandlers)); 2861} 2862 2863StmtResult 2864Sema::ActOnSEHTryBlock(bool IsCXXTry, 2865 SourceLocation TryLoc, 2866 Stmt *TryBlock, 2867 Stmt *Handler) { 2868 assert(TryBlock && Handler); 2869 2870 getCurFunction()->setHasBranchProtectedScope(); 2871 2872 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2873} 2874 2875StmtResult 2876Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2877 Expr *FilterExpr, 2878 Stmt *Block) { 2879 assert(FilterExpr && Block); 2880 2881 if(!FilterExpr->getType()->isIntegerType()) { 2882 return StmtError(Diag(FilterExpr->getExprLoc(), 2883 diag::err_filter_expression_integral) 2884 << FilterExpr->getType()); 2885 } 2886 2887 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2888} 2889 2890StmtResult 2891Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2892 Stmt *Block) { 2893 assert(Block); 2894 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2895} 2896 2897StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 2898 bool IsIfExists, 2899 NestedNameSpecifierLoc QualifierLoc, 2900 DeclarationNameInfo NameInfo, 2901 Stmt *Nested) 2902{ 2903 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 2904 QualifierLoc, NameInfo, 2905 cast<CompoundStmt>(Nested)); 2906} 2907 2908 2909StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 2910 bool IsIfExists, 2911 CXXScopeSpec &SS, 2912 UnqualifiedId &Name, 2913 Stmt *Nested) { 2914 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 2915 SS.getWithLocInContext(Context), 2916 GetNameFromUnqualifiedId(Name), 2917 Nested); 2918} 2919