SemaStmt.cpp revision 33deb35535aebe81bed0eaf5c14f3032276a086e
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/ExprCXX.h" 23#include "clang/AST/ExprObjC.h" 24#include "clang/AST/StmtObjC.h" 25#include "clang/AST/StmtCXX.h" 26#include "clang/AST/TypeLoc.h" 27#include "clang/Lex/Preprocessor.h" 28#include "clang/Basic/TargetInfo.h" 29#include "llvm/ADT/ArrayRef.h" 30#include "llvm/ADT/STLExtras.h" 31#include "llvm/ADT/SmallVector.h" 32using namespace clang; 33using namespace sema; 34 35StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 36 Expr *E = expr.get(); 37 if (!E) // FIXME: FullExprArg has no error state? 38 return StmtError(); 39 40 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 41 // void expression for its side effects. Conversion to void allows any 42 // operand, even incomplete types. 43 44 // Same thing in for stmt first clause (when expr) and third clause. 45 return Owned(static_cast<Stmt*>(E)); 46} 47 48 49StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, 50 bool HasLeadingEmptyMacro) { 51 return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro)); 52} 53 54StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 55 SourceLocation EndLoc) { 56 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 57 58 // If we have an invalid decl, just return an error. 59 if (DG.isNull()) return StmtError(); 60 61 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 62} 63 64void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 65 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 66 67 // If we have an invalid decl, just return. 68 if (DG.isNull() || !DG.isSingleDecl()) return; 69 VarDecl *var = cast<VarDecl>(DG.getSingleDecl()); 70 71 // suppress any potential 'unused variable' warning. 72 var->setUsed(); 73 74 // foreach variables are never actually initialized in the way that 75 // the parser came up with. 76 var->setInit(0); 77 78 // In ARC, we don't need to retain the iteration variable of a fast 79 // enumeration loop. Rather than actually trying to catch that 80 // during declaration processing, we remove the consequences here. 81 if (getLangOptions().ObjCAutoRefCount) { 82 QualType type = var->getType(); 83 84 // Only do this if we inferred the lifetime. Inferred lifetime 85 // will show up as a local qualifier because explicit lifetime 86 // should have shown up as an AttributedType instead. 87 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { 88 // Add 'const' and mark the variable as pseudo-strong. 89 var->setType(type.withConst()); 90 var->setARCPseudoStrong(true); 91 } 92 } 93} 94 95/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='. 96/// 97/// Adding a cast to void (or other expression wrappers) will prevent the 98/// warning from firing. 99static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) { 100 SourceLocation Loc; 101 bool IsNotEqual, CanAssign; 102 103 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) { 104 if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE) 105 return false; 106 107 Loc = Op->getOperatorLoc(); 108 IsNotEqual = Op->getOpcode() == BO_NE; 109 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue(); 110 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) { 111 if (Op->getOperator() != OO_EqualEqual && 112 Op->getOperator() != OO_ExclaimEqual) 113 return false; 114 115 Loc = Op->getOperatorLoc(); 116 IsNotEqual = Op->getOperator() == OO_ExclaimEqual; 117 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue(); 118 } else { 119 // Not a typo-prone comparison. 120 return false; 121 } 122 123 // Suppress warnings when the operator, suspicious as it may be, comes from 124 // a macro expansion. 125 if (Loc.isMacroID()) 126 return false; 127 128 S.Diag(Loc, diag::warn_unused_comparison) 129 << (unsigned)IsNotEqual << E->getSourceRange(); 130 131 // If the LHS is a plausible entity to assign to, provide a fixit hint to 132 // correct common typos. 133 if (CanAssign) { 134 if (IsNotEqual) 135 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign) 136 << FixItHint::CreateReplacement(Loc, "|="); 137 else 138 S.Diag(Loc, diag::note_equality_comparison_to_assign) 139 << FixItHint::CreateReplacement(Loc, "="); 140 } 141 142 return true; 143} 144 145void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 146 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 147 return DiagnoseUnusedExprResult(Label->getSubStmt()); 148 149 const Expr *E = dyn_cast_or_null<Expr>(S); 150 if (!E) 151 return; 152 153 SourceLocation Loc; 154 SourceRange R1, R2; 155 if (SourceMgr.isInSystemMacro(E->getExprLoc()) || 156 !E->isUnusedResultAWarning(Loc, R1, R2, Context)) 157 return; 158 159 // Okay, we have an unused result. Depending on what the base expression is, 160 // we might want to make a more specific diagnostic. Check for one of these 161 // cases now. 162 unsigned DiagID = diag::warn_unused_expr; 163 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 164 E = Temps->getSubExpr(); 165 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 166 E = TempExpr->getSubExpr(); 167 168 if (DiagnoseUnusedComparison(*this, E)) 169 return; 170 171 E = E->IgnoreParenImpCasts(); 172 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 173 if (E->getType()->isVoidType()) 174 return; 175 176 // If the callee has attribute pure, const, or warn_unused_result, warn with 177 // a more specific message to make it clear what is happening. 178 if (const Decl *FD = CE->getCalleeDecl()) { 179 if (FD->getAttr<WarnUnusedResultAttr>()) { 180 Diag(Loc, diag::warn_unused_result) << R1 << R2; 181 return; 182 } 183 if (FD->getAttr<PureAttr>()) { 184 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 185 return; 186 } 187 if (FD->getAttr<ConstAttr>()) { 188 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 189 return; 190 } 191 } 192 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 193 if (getLangOptions().ObjCAutoRefCount && ME->isDelegateInitCall()) { 194 Diag(Loc, diag::err_arc_unused_init_message) << R1; 195 return; 196 } 197 const ObjCMethodDecl *MD = ME->getMethodDecl(); 198 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 199 Diag(Loc, diag::warn_unused_result) << R1 << R2; 200 return; 201 } 202 } else if (isa<PseudoObjectExpr>(E)) { 203 DiagID = diag::warn_unused_property_expr; 204 } else if (const CXXFunctionalCastExpr *FC 205 = dyn_cast<CXXFunctionalCastExpr>(E)) { 206 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 207 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 208 return; 209 } 210 // Diagnose "(void*) blah" as a typo for "(void) blah". 211 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 212 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 213 QualType T = TI->getType(); 214 215 // We really do want to use the non-canonical type here. 216 if (T == Context.VoidPtrTy) { 217 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 218 219 Diag(Loc, diag::warn_unused_voidptr) 220 << FixItHint::CreateRemoval(TL.getStarLoc()); 221 return; 222 } 223 } 224 225 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 226} 227 228void Sema::ActOnStartOfCompoundStmt() { 229 PushCompoundScope(); 230} 231 232void Sema::ActOnFinishOfCompoundStmt() { 233 PopCompoundScope(); 234} 235 236sema::CompoundScopeInfo &Sema::getCurCompoundScope() const { 237 return getCurFunction()->CompoundScopes.back(); 238} 239 240StmtResult 241Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 242 MultiStmtArg elts, bool isStmtExpr) { 243 unsigned NumElts = elts.size(); 244 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 245 // If we're in C89 mode, check that we don't have any decls after stmts. If 246 // so, emit an extension diagnostic. 247 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 248 // Note that __extension__ can be around a decl. 249 unsigned i = 0; 250 // Skip over all declarations. 251 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 252 /*empty*/; 253 254 // We found the end of the list or a statement. Scan for another declstmt. 255 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 256 /*empty*/; 257 258 if (i != NumElts) { 259 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 260 Diag(D->getLocation(), diag::ext_mixed_decls_code); 261 } 262 } 263 // Warn about unused expressions in statements. 264 for (unsigned i = 0; i != NumElts; ++i) { 265 // Ignore statements that are last in a statement expression. 266 if (isStmtExpr && i == NumElts - 1) 267 continue; 268 269 DiagnoseUnusedExprResult(Elts[i]); 270 } 271 272 // Check for suspicious empty body (null statement) in `for' and `while' 273 // statements. Don't do anything for template instantiations, this just adds 274 // noise. 275 if (NumElts != 0 && !CurrentInstantiationScope && 276 getCurCompoundScope().HasEmptyLoopBodies) { 277 for (unsigned i = 0; i != NumElts - 1; ++i) 278 DiagnoseEmptyLoopBody(Elts[i], Elts[i + 1]); 279 } 280 281 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 282} 283 284StmtResult 285Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 286 SourceLocation DotDotDotLoc, Expr *RHSVal, 287 SourceLocation ColonLoc) { 288 assert((LHSVal != 0) && "missing expression in case statement"); 289 290 if (getCurFunction()->SwitchStack.empty()) { 291 Diag(CaseLoc, diag::err_case_not_in_switch); 292 return StmtError(); 293 } 294 295 if (!getLangOptions().CPlusPlus0x) { 296 // C99 6.8.4.2p3: The expression shall be an integer constant. 297 // However, GCC allows any evaluatable integer expression. 298 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent()) { 299 LHSVal = VerifyIntegerConstantExpression(LHSVal).take(); 300 if (!LHSVal) 301 return StmtError(); 302 } 303 304 // GCC extension: The expression shall be an integer constant. 305 306 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent()) { 307 RHSVal = VerifyIntegerConstantExpression(RHSVal).take(); 308 // Recover from an error by just forgetting about it. 309 } 310 } 311 312 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 313 ColonLoc); 314 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 315 return Owned(CS); 316} 317 318/// ActOnCaseStmtBody - This installs a statement as the body of a case. 319void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 320 DiagnoseUnusedExprResult(SubStmt); 321 322 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 323 CS->setSubStmt(SubStmt); 324} 325 326StmtResult 327Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 328 Stmt *SubStmt, Scope *CurScope) { 329 DiagnoseUnusedExprResult(SubStmt); 330 331 if (getCurFunction()->SwitchStack.empty()) { 332 Diag(DefaultLoc, diag::err_default_not_in_switch); 333 return Owned(SubStmt); 334 } 335 336 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 337 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 338 return Owned(DS); 339} 340 341StmtResult 342Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 343 SourceLocation ColonLoc, Stmt *SubStmt) { 344 345 // If the label was multiply defined, reject it now. 346 if (TheDecl->getStmt()) { 347 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 348 Diag(TheDecl->getLocation(), diag::note_previous_definition); 349 return Owned(SubStmt); 350 } 351 352 // Otherwise, things are good. Fill in the declaration and return it. 353 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 354 TheDecl->setStmt(LS); 355 if (!TheDecl->isGnuLocal()) 356 TheDecl->setLocation(IdentLoc); 357 return Owned(LS); 358} 359 360StmtResult 361Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 362 Stmt *thenStmt, SourceLocation ElseLoc, 363 Stmt *elseStmt) { 364 ExprResult CondResult(CondVal.release()); 365 366 VarDecl *ConditionVar = 0; 367 if (CondVar) { 368 ConditionVar = cast<VarDecl>(CondVar); 369 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 370 if (CondResult.isInvalid()) 371 return StmtError(); 372 } 373 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 374 if (!ConditionExpr) 375 return StmtError(); 376 377 DiagnoseUnusedExprResult(thenStmt); 378 379 if (!elseStmt) { 380 DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt, 381 diag::warn_empty_if_body); 382 } 383 384 DiagnoseUnusedExprResult(elseStmt); 385 386 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 387 thenStmt, ElseLoc, elseStmt)); 388} 389 390/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 391/// the specified width and sign. If an overflow occurs, detect it and emit 392/// the specified diagnostic. 393void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 394 unsigned NewWidth, bool NewSign, 395 SourceLocation Loc, 396 unsigned DiagID) { 397 // Perform a conversion to the promoted condition type if needed. 398 if (NewWidth > Val.getBitWidth()) { 399 // If this is an extension, just do it. 400 Val = Val.extend(NewWidth); 401 Val.setIsSigned(NewSign); 402 403 // If the input was signed and negative and the output is 404 // unsigned, don't bother to warn: this is implementation-defined 405 // behavior. 406 // FIXME: Introduce a second, default-ignored warning for this case? 407 } else if (NewWidth < Val.getBitWidth()) { 408 // If this is a truncation, check for overflow. 409 llvm::APSInt ConvVal(Val); 410 ConvVal = ConvVal.trunc(NewWidth); 411 ConvVal.setIsSigned(NewSign); 412 ConvVal = ConvVal.extend(Val.getBitWidth()); 413 ConvVal.setIsSigned(Val.isSigned()); 414 if (ConvVal != Val) 415 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 416 417 // Regardless of whether a diagnostic was emitted, really do the 418 // truncation. 419 Val = Val.trunc(NewWidth); 420 Val.setIsSigned(NewSign); 421 } else if (NewSign != Val.isSigned()) { 422 // Convert the sign to match the sign of the condition. This can cause 423 // overflow as well: unsigned(INTMIN) 424 // We don't diagnose this overflow, because it is implementation-defined 425 // behavior. 426 // FIXME: Introduce a second, default-ignored warning for this case? 427 llvm::APSInt OldVal(Val); 428 Val.setIsSigned(NewSign); 429 } 430} 431 432namespace { 433 struct CaseCompareFunctor { 434 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 435 const llvm::APSInt &RHS) { 436 return LHS.first < RHS; 437 } 438 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 439 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 440 return LHS.first < RHS.first; 441 } 442 bool operator()(const llvm::APSInt &LHS, 443 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 444 return LHS < RHS.first; 445 } 446 }; 447} 448 449/// CmpCaseVals - Comparison predicate for sorting case values. 450/// 451static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 452 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 453 if (lhs.first < rhs.first) 454 return true; 455 456 if (lhs.first == rhs.first && 457 lhs.second->getCaseLoc().getRawEncoding() 458 < rhs.second->getCaseLoc().getRawEncoding()) 459 return true; 460 return false; 461} 462 463/// CmpEnumVals - Comparison predicate for sorting enumeration values. 464/// 465static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 466 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 467{ 468 return lhs.first < rhs.first; 469} 470 471/// EqEnumVals - Comparison preficate for uniqing enumeration values. 472/// 473static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 474 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 475{ 476 return lhs.first == rhs.first; 477} 478 479/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 480/// potentially integral-promoted expression @p expr. 481static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 482 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 483 expr = cleanups->getSubExpr(); 484 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 485 if (impcast->getCastKind() != CK_IntegralCast) break; 486 expr = impcast->getSubExpr(); 487 } 488 return expr->getType(); 489} 490 491StmtResult 492Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 493 Decl *CondVar) { 494 ExprResult CondResult; 495 496 VarDecl *ConditionVar = 0; 497 if (CondVar) { 498 ConditionVar = cast<VarDecl>(CondVar); 499 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 500 if (CondResult.isInvalid()) 501 return StmtError(); 502 503 Cond = CondResult.release(); 504 } 505 506 if (!Cond) 507 return StmtError(); 508 509 CondResult 510 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 511 PDiag(diag::err_typecheck_statement_requires_integer), 512 PDiag(diag::err_switch_incomplete_class_type) 513 << Cond->getSourceRange(), 514 PDiag(diag::err_switch_explicit_conversion), 515 PDiag(diag::note_switch_conversion), 516 PDiag(diag::err_switch_multiple_conversions), 517 PDiag(diag::note_switch_conversion), 518 PDiag(0), 519 /*AllowScopedEnumerations*/ true); 520 if (CondResult.isInvalid()) return StmtError(); 521 Cond = CondResult.take(); 522 523 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 524 CondResult = UsualUnaryConversions(Cond); 525 if (CondResult.isInvalid()) return StmtError(); 526 Cond = CondResult.take(); 527 528 if (!CondVar) { 529 CheckImplicitConversions(Cond, SwitchLoc); 530 CondResult = MaybeCreateExprWithCleanups(Cond); 531 if (CondResult.isInvalid()) 532 return StmtError(); 533 Cond = CondResult.take(); 534 } 535 536 getCurFunction()->setHasBranchIntoScope(); 537 538 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 539 getCurFunction()->SwitchStack.push_back(SS); 540 return Owned(SS); 541} 542 543static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 544 if (Val.getBitWidth() < BitWidth) 545 Val = Val.extend(BitWidth); 546 else if (Val.getBitWidth() > BitWidth) 547 Val = Val.trunc(BitWidth); 548 Val.setIsSigned(IsSigned); 549} 550 551StmtResult 552Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 553 Stmt *BodyStmt) { 554 SwitchStmt *SS = cast<SwitchStmt>(Switch); 555 assert(SS == getCurFunction()->SwitchStack.back() && 556 "switch stack missing push/pop!"); 557 558 SS->setBody(BodyStmt, SwitchLoc); 559 getCurFunction()->SwitchStack.pop_back(); 560 561 Expr *CondExpr = SS->getCond(); 562 if (!CondExpr) return StmtError(); 563 564 QualType CondType = CondExpr->getType(); 565 566 Expr *CondExprBeforePromotion = CondExpr; 567 QualType CondTypeBeforePromotion = 568 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 569 570 // C++ 6.4.2.p2: 571 // Integral promotions are performed (on the switch condition). 572 // 573 // A case value unrepresentable by the original switch condition 574 // type (before the promotion) doesn't make sense, even when it can 575 // be represented by the promoted type. Therefore we need to find 576 // the pre-promotion type of the switch condition. 577 if (!CondExpr->isTypeDependent()) { 578 // We have already converted the expression to an integral or enumeration 579 // type, when we started the switch statement. If we don't have an 580 // appropriate type now, just return an error. 581 if (!CondType->isIntegralOrEnumerationType()) 582 return StmtError(); 583 584 if (CondExpr->isKnownToHaveBooleanValue()) { 585 // switch(bool_expr) {...} is often a programmer error, e.g. 586 // switch(n && mask) { ... } // Doh - should be "n & mask". 587 // One can always use an if statement instead of switch(bool_expr). 588 Diag(SwitchLoc, diag::warn_bool_switch_condition) 589 << CondExpr->getSourceRange(); 590 } 591 } 592 593 // Get the bitwidth of the switched-on value before promotions. We must 594 // convert the integer case values to this width before comparison. 595 bool HasDependentValue 596 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 597 unsigned CondWidth 598 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 599 bool CondIsSigned 600 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 601 602 // Accumulate all of the case values in a vector so that we can sort them 603 // and detect duplicates. This vector contains the APInt for the case after 604 // it has been converted to the condition type. 605 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 606 CaseValsTy CaseVals; 607 608 // Keep track of any GNU case ranges we see. The APSInt is the low value. 609 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 610 CaseRangesTy CaseRanges; 611 612 DefaultStmt *TheDefaultStmt = 0; 613 614 bool CaseListIsErroneous = false; 615 616 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 617 SC = SC->getNextSwitchCase()) { 618 619 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 620 if (TheDefaultStmt) { 621 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 622 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 623 624 // FIXME: Remove the default statement from the switch block so that 625 // we'll return a valid AST. This requires recursing down the AST and 626 // finding it, not something we are set up to do right now. For now, 627 // just lop the entire switch stmt out of the AST. 628 CaseListIsErroneous = true; 629 } 630 TheDefaultStmt = DS; 631 632 } else { 633 CaseStmt *CS = cast<CaseStmt>(SC); 634 635 Expr *Lo = CS->getLHS(); 636 637 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 638 HasDependentValue = true; 639 break; 640 } 641 642 llvm::APSInt LoVal; 643 644 if (getLangOptions().CPlusPlus0x) { 645 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 646 // constant expression of the promoted type of the switch condition. 647 ExprResult ConvLo = 648 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue); 649 if (ConvLo.isInvalid()) { 650 CaseListIsErroneous = true; 651 continue; 652 } 653 Lo = ConvLo.take(); 654 } else { 655 // We already verified that the expression has a i-c-e value (C99 656 // 6.8.4.2p3) - get that value now. 657 LoVal = Lo->EvaluateKnownConstInt(Context); 658 659 // If the LHS is not the same type as the condition, insert an implicit 660 // cast. 661 Lo = DefaultLvalueConversion(Lo).take(); 662 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 663 } 664 665 // Convert the value to the same width/sign as the condition had prior to 666 // integral promotions. 667 // 668 // FIXME: This causes us to reject valid code: 669 // switch ((char)c) { case 256: case 0: return 0; } 670 // Here we claim there is a duplicated condition value, but there is not. 671 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 672 Lo->getLocStart(), 673 diag::warn_case_value_overflow); 674 675 CS->setLHS(Lo); 676 677 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 678 if (CS->getRHS()) { 679 if (CS->getRHS()->isTypeDependent() || 680 CS->getRHS()->isValueDependent()) { 681 HasDependentValue = true; 682 break; 683 } 684 CaseRanges.push_back(std::make_pair(LoVal, CS)); 685 } else 686 CaseVals.push_back(std::make_pair(LoVal, CS)); 687 } 688 } 689 690 if (!HasDependentValue) { 691 // If we don't have a default statement, check whether the 692 // condition is constant. 693 llvm::APSInt ConstantCondValue; 694 bool HasConstantCond = false; 695 if (!HasDependentValue && !TheDefaultStmt) { 696 HasConstantCond 697 = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context, 698 Expr::SE_AllowSideEffects); 699 assert(!HasConstantCond || 700 (ConstantCondValue.getBitWidth() == CondWidth && 701 ConstantCondValue.isSigned() == CondIsSigned)); 702 } 703 bool ShouldCheckConstantCond = HasConstantCond; 704 705 // Sort all the scalar case values so we can easily detect duplicates. 706 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 707 708 if (!CaseVals.empty()) { 709 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 710 if (ShouldCheckConstantCond && 711 CaseVals[i].first == ConstantCondValue) 712 ShouldCheckConstantCond = false; 713 714 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 715 // If we have a duplicate, report it. 716 Diag(CaseVals[i].second->getLHS()->getLocStart(), 717 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 718 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 719 diag::note_duplicate_case_prev); 720 // FIXME: We really want to remove the bogus case stmt from the 721 // substmt, but we have no way to do this right now. 722 CaseListIsErroneous = true; 723 } 724 } 725 } 726 727 // Detect duplicate case ranges, which usually don't exist at all in 728 // the first place. 729 if (!CaseRanges.empty()) { 730 // Sort all the case ranges by their low value so we can easily detect 731 // overlaps between ranges. 732 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 733 734 // Scan the ranges, computing the high values and removing empty ranges. 735 std::vector<llvm::APSInt> HiVals; 736 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 737 llvm::APSInt &LoVal = CaseRanges[i].first; 738 CaseStmt *CR = CaseRanges[i].second; 739 Expr *Hi = CR->getRHS(); 740 llvm::APSInt HiVal; 741 742 if (getLangOptions().CPlusPlus0x) { 743 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 744 // constant expression of the promoted type of the switch condition. 745 ExprResult ConvHi = 746 CheckConvertedConstantExpression(Hi, CondType, HiVal, 747 CCEK_CaseValue); 748 if (ConvHi.isInvalid()) { 749 CaseListIsErroneous = true; 750 continue; 751 } 752 Hi = ConvHi.take(); 753 } else { 754 HiVal = Hi->EvaluateKnownConstInt(Context); 755 756 // If the RHS is not the same type as the condition, insert an 757 // implicit cast. 758 Hi = DefaultLvalueConversion(Hi).take(); 759 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 760 } 761 762 // Convert the value to the same width/sign as the condition. 763 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 764 Hi->getLocStart(), 765 diag::warn_case_value_overflow); 766 767 CR->setRHS(Hi); 768 769 // If the low value is bigger than the high value, the case is empty. 770 if (LoVal > HiVal) { 771 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 772 << SourceRange(CR->getLHS()->getLocStart(), 773 Hi->getLocEnd()); 774 CaseRanges.erase(CaseRanges.begin()+i); 775 --i, --e; 776 continue; 777 } 778 779 if (ShouldCheckConstantCond && 780 LoVal <= ConstantCondValue && 781 ConstantCondValue <= HiVal) 782 ShouldCheckConstantCond = false; 783 784 HiVals.push_back(HiVal); 785 } 786 787 // Rescan the ranges, looking for overlap with singleton values and other 788 // ranges. Since the range list is sorted, we only need to compare case 789 // ranges with their neighbors. 790 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 791 llvm::APSInt &CRLo = CaseRanges[i].first; 792 llvm::APSInt &CRHi = HiVals[i]; 793 CaseStmt *CR = CaseRanges[i].second; 794 795 // Check to see whether the case range overlaps with any 796 // singleton cases. 797 CaseStmt *OverlapStmt = 0; 798 llvm::APSInt OverlapVal(32); 799 800 // Find the smallest value >= the lower bound. If I is in the 801 // case range, then we have overlap. 802 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 803 CaseVals.end(), CRLo, 804 CaseCompareFunctor()); 805 if (I != CaseVals.end() && I->first < CRHi) { 806 OverlapVal = I->first; // Found overlap with scalar. 807 OverlapStmt = I->second; 808 } 809 810 // Find the smallest value bigger than the upper bound. 811 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 812 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 813 OverlapVal = (I-1)->first; // Found overlap with scalar. 814 OverlapStmt = (I-1)->second; 815 } 816 817 // Check to see if this case stmt overlaps with the subsequent 818 // case range. 819 if (i && CRLo <= HiVals[i-1]) { 820 OverlapVal = HiVals[i-1]; // Found overlap with range. 821 OverlapStmt = CaseRanges[i-1].second; 822 } 823 824 if (OverlapStmt) { 825 // If we have a duplicate, report it. 826 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 827 << OverlapVal.toString(10); 828 Diag(OverlapStmt->getLHS()->getLocStart(), 829 diag::note_duplicate_case_prev); 830 // FIXME: We really want to remove the bogus case stmt from the 831 // substmt, but we have no way to do this right now. 832 CaseListIsErroneous = true; 833 } 834 } 835 } 836 837 // Complain if we have a constant condition and we didn't find a match. 838 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 839 // TODO: it would be nice if we printed enums as enums, chars as 840 // chars, etc. 841 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 842 << ConstantCondValue.toString(10) 843 << CondExpr->getSourceRange(); 844 } 845 846 // Check to see if switch is over an Enum and handles all of its 847 // values. We only issue a warning if there is not 'default:', but 848 // we still do the analysis to preserve this information in the AST 849 // (which can be used by flow-based analyes). 850 // 851 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 852 853 // If switch has default case, then ignore it. 854 if (!CaseListIsErroneous && !HasConstantCond && ET) { 855 const EnumDecl *ED = ET->getDecl(); 856 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 857 EnumValsTy; 858 EnumValsTy EnumVals; 859 860 // Gather all enum values, set their type and sort them, 861 // allowing easier comparison with CaseVals. 862 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 863 EDI != ED->enumerator_end(); ++EDI) { 864 llvm::APSInt Val = EDI->getInitVal(); 865 AdjustAPSInt(Val, CondWidth, CondIsSigned); 866 EnumVals.push_back(std::make_pair(Val, *EDI)); 867 } 868 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 869 EnumValsTy::iterator EIend = 870 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 871 872 // See which case values aren't in enum. 873 EnumValsTy::const_iterator EI = EnumVals.begin(); 874 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 875 CI != CaseVals.end(); CI++) { 876 while (EI != EIend && EI->first < CI->first) 877 EI++; 878 if (EI == EIend || EI->first > CI->first) 879 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 880 << ED->getDeclName(); 881 } 882 // See which of case ranges aren't in enum 883 EI = EnumVals.begin(); 884 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 885 RI != CaseRanges.end() && EI != EIend; RI++) { 886 while (EI != EIend && EI->first < RI->first) 887 EI++; 888 889 if (EI == EIend || EI->first != RI->first) { 890 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 891 << ED->getDeclName(); 892 } 893 894 llvm::APSInt Hi = 895 RI->second->getRHS()->EvaluateKnownConstInt(Context); 896 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 897 while (EI != EIend && EI->first < Hi) 898 EI++; 899 if (EI == EIend || EI->first != Hi) 900 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 901 << ED->getDeclName(); 902 } 903 904 // Check which enum vals aren't in switch 905 CaseValsTy::const_iterator CI = CaseVals.begin(); 906 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 907 bool hasCasesNotInSwitch = false; 908 909 SmallVector<DeclarationName,8> UnhandledNames; 910 911 for (EI = EnumVals.begin(); EI != EIend; EI++){ 912 // Drop unneeded case values 913 llvm::APSInt CIVal; 914 while (CI != CaseVals.end() && CI->first < EI->first) 915 CI++; 916 917 if (CI != CaseVals.end() && CI->first == EI->first) 918 continue; 919 920 // Drop unneeded case ranges 921 for (; RI != CaseRanges.end(); RI++) { 922 llvm::APSInt Hi = 923 RI->second->getRHS()->EvaluateKnownConstInt(Context); 924 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 925 if (EI->first <= Hi) 926 break; 927 } 928 929 if (RI == CaseRanges.end() || EI->first < RI->first) { 930 hasCasesNotInSwitch = true; 931 UnhandledNames.push_back(EI->second->getDeclName()); 932 } 933 } 934 935 if (TheDefaultStmt && UnhandledNames.empty()) 936 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default); 937 938 // Produce a nice diagnostic if multiple values aren't handled. 939 switch (UnhandledNames.size()) { 940 case 0: break; 941 case 1: 942 Diag(CondExpr->getExprLoc(), TheDefaultStmt 943 ? diag::warn_def_missing_case1 : diag::warn_missing_case1) 944 << UnhandledNames[0]; 945 break; 946 case 2: 947 Diag(CondExpr->getExprLoc(), TheDefaultStmt 948 ? diag::warn_def_missing_case2 : diag::warn_missing_case2) 949 << UnhandledNames[0] << UnhandledNames[1]; 950 break; 951 case 3: 952 Diag(CondExpr->getExprLoc(), TheDefaultStmt 953 ? diag::warn_def_missing_case3 : diag::warn_missing_case3) 954 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 955 break; 956 default: 957 Diag(CondExpr->getExprLoc(), TheDefaultStmt 958 ? diag::warn_def_missing_cases : diag::warn_missing_cases) 959 << (unsigned)UnhandledNames.size() 960 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 961 break; 962 } 963 964 if (!hasCasesNotInSwitch) 965 SS->setAllEnumCasesCovered(); 966 } 967 } 968 969 DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), BodyStmt, 970 diag::warn_empty_switch_body); 971 972 // FIXME: If the case list was broken is some way, we don't have a good system 973 // to patch it up. Instead, just return the whole substmt as broken. 974 if (CaseListIsErroneous) 975 return StmtError(); 976 977 return Owned(SS); 978} 979 980StmtResult 981Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 982 Decl *CondVar, Stmt *Body) { 983 ExprResult CondResult(Cond.release()); 984 985 VarDecl *ConditionVar = 0; 986 if (CondVar) { 987 ConditionVar = cast<VarDecl>(CondVar); 988 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 989 if (CondResult.isInvalid()) 990 return StmtError(); 991 } 992 Expr *ConditionExpr = CondResult.take(); 993 if (!ConditionExpr) 994 return StmtError(); 995 996 DiagnoseUnusedExprResult(Body); 997 998 if (isa<NullStmt>(Body)) 999 getCurCompoundScope().setHasEmptyLoopBodies(); 1000 1001 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 1002 Body, WhileLoc)); 1003} 1004 1005StmtResult 1006Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 1007 SourceLocation WhileLoc, SourceLocation CondLParen, 1008 Expr *Cond, SourceLocation CondRParen) { 1009 assert(Cond && "ActOnDoStmt(): missing expression"); 1010 1011 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 1012 if (CondResult.isInvalid() || CondResult.isInvalid()) 1013 return StmtError(); 1014 Cond = CondResult.take(); 1015 1016 CheckImplicitConversions(Cond, DoLoc); 1017 CondResult = MaybeCreateExprWithCleanups(Cond); 1018 if (CondResult.isInvalid()) 1019 return StmtError(); 1020 Cond = CondResult.take(); 1021 1022 DiagnoseUnusedExprResult(Body); 1023 1024 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 1025} 1026 1027StmtResult 1028Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1029 Stmt *First, FullExprArg second, Decl *secondVar, 1030 FullExprArg third, 1031 SourceLocation RParenLoc, Stmt *Body) { 1032 if (!getLangOptions().CPlusPlus) { 1033 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 1034 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1035 // declare identifiers for objects having storage class 'auto' or 1036 // 'register'. 1037 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 1038 DI!=DE; ++DI) { 1039 VarDecl *VD = dyn_cast<VarDecl>(*DI); 1040 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 1041 VD = 0; 1042 if (VD == 0) 1043 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 1044 // FIXME: mark decl erroneous! 1045 } 1046 } 1047 } 1048 1049 ExprResult SecondResult(second.release()); 1050 VarDecl *ConditionVar = 0; 1051 if (secondVar) { 1052 ConditionVar = cast<VarDecl>(secondVar); 1053 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1054 if (SecondResult.isInvalid()) 1055 return StmtError(); 1056 } 1057 1058 Expr *Third = third.release().takeAs<Expr>(); 1059 1060 DiagnoseUnusedExprResult(First); 1061 DiagnoseUnusedExprResult(Third); 1062 DiagnoseUnusedExprResult(Body); 1063 1064 if (isa<NullStmt>(Body)) 1065 getCurCompoundScope().setHasEmptyLoopBodies(); 1066 1067 return Owned(new (Context) ForStmt(Context, First, 1068 SecondResult.take(), ConditionVar, 1069 Third, Body, ForLoc, LParenLoc, 1070 RParenLoc)); 1071} 1072 1073/// In an Objective C collection iteration statement: 1074/// for (x in y) 1075/// x can be an arbitrary l-value expression. Bind it up as a 1076/// full-expression. 1077StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1078 CheckImplicitConversions(E); 1079 ExprResult Result = MaybeCreateExprWithCleanups(E); 1080 if (Result.isInvalid()) return StmtError(); 1081 return Owned(static_cast<Stmt*>(Result.get())); 1082} 1083 1084ExprResult 1085Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1086 assert(collection); 1087 1088 // Bail out early if we've got a type-dependent expression. 1089 if (collection->isTypeDependent()) return Owned(collection); 1090 1091 // Perform normal l-value conversion. 1092 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1093 if (result.isInvalid()) 1094 return ExprError(); 1095 collection = result.take(); 1096 1097 // The operand needs to have object-pointer type. 1098 // TODO: should we do a contextual conversion? 1099 const ObjCObjectPointerType *pointerType = 1100 collection->getType()->getAs<ObjCObjectPointerType>(); 1101 if (!pointerType) 1102 return Diag(forLoc, diag::err_collection_expr_type) 1103 << collection->getType() << collection->getSourceRange(); 1104 1105 // Check that the operand provides 1106 // - countByEnumeratingWithState:objects:count: 1107 const ObjCObjectType *objectType = pointerType->getObjectType(); 1108 ObjCInterfaceDecl *iface = objectType->getInterface(); 1109 1110 // If we have a forward-declared type, we can't do this check. 1111 // Under ARC, it is an error not to have a forward-declared class. 1112 if (iface && 1113 RequireCompleteType(forLoc, QualType(objectType, 0), 1114 getLangOptions().ObjCAutoRefCount 1115 ? PDiag(diag::err_arc_collection_forward) 1116 << collection->getSourceRange() 1117 : PDiag(0))) { 1118 // Otherwise, if we have any useful type information, check that 1119 // the type declares the appropriate method. 1120 } else if (iface || !objectType->qual_empty()) { 1121 IdentifierInfo *selectorIdents[] = { 1122 &Context.Idents.get("countByEnumeratingWithState"), 1123 &Context.Idents.get("objects"), 1124 &Context.Idents.get("count") 1125 }; 1126 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1127 1128 ObjCMethodDecl *method = 0; 1129 1130 // If there's an interface, look in both the public and private APIs. 1131 if (iface) { 1132 method = iface->lookupInstanceMethod(selector); 1133 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1134 } 1135 1136 // Also check protocol qualifiers. 1137 if (!method) 1138 method = LookupMethodInQualifiedType(selector, pointerType, 1139 /*instance*/ true); 1140 1141 // If we didn't find it anywhere, give up. 1142 if (!method) { 1143 Diag(forLoc, diag::warn_collection_expr_type) 1144 << collection->getType() << selector << collection->getSourceRange(); 1145 } 1146 1147 // TODO: check for an incompatible signature? 1148 } 1149 1150 // Wrap up any cleanups in the expression. 1151 return Owned(MaybeCreateExprWithCleanups(collection)); 1152} 1153 1154StmtResult 1155Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1156 SourceLocation LParenLoc, 1157 Stmt *First, Expr *Second, 1158 SourceLocation RParenLoc, Stmt *Body) { 1159 if (First) { 1160 QualType FirstType; 1161 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1162 if (!DS->isSingleDecl()) 1163 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1164 diag::err_toomany_element_decls)); 1165 1166 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1167 FirstType = D->getType(); 1168 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1169 // declare identifiers for objects having storage class 'auto' or 1170 // 'register'. 1171 if (!D->hasLocalStorage()) 1172 return StmtError(Diag(D->getLocation(), 1173 diag::err_non_variable_decl_in_for)); 1174 } else { 1175 Expr *FirstE = cast<Expr>(First); 1176 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1177 return StmtError(Diag(First->getLocStart(), 1178 diag::err_selector_element_not_lvalue) 1179 << First->getSourceRange()); 1180 1181 FirstType = static_cast<Expr*>(First)->getType(); 1182 } 1183 if (!FirstType->isDependentType() && 1184 !FirstType->isObjCObjectPointerType() && 1185 !FirstType->isBlockPointerType()) 1186 Diag(ForLoc, diag::err_selector_element_type) 1187 << FirstType << First->getSourceRange(); 1188 } 1189 1190 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1191 ForLoc, RParenLoc)); 1192} 1193 1194namespace { 1195 1196enum BeginEndFunction { 1197 BEF_begin, 1198 BEF_end 1199}; 1200 1201/// Build a variable declaration for a for-range statement. 1202static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1203 QualType Type, const char *Name) { 1204 DeclContext *DC = SemaRef.CurContext; 1205 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1206 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1207 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1208 TInfo, SC_Auto, SC_None); 1209 Decl->setImplicit(); 1210 return Decl; 1211} 1212 1213/// Finish building a variable declaration for a for-range statement. 1214/// \return true if an error occurs. 1215static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1216 SourceLocation Loc, int diag) { 1217 // Deduce the type for the iterator variable now rather than leaving it to 1218 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1219 TypeSourceInfo *InitTSI = 0; 1220 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) || 1221 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) == 1222 Sema::DAR_Failed) 1223 SemaRef.Diag(Loc, diag) << Init->getType(); 1224 if (!InitTSI) { 1225 Decl->setInvalidDecl(); 1226 return true; 1227 } 1228 Decl->setTypeSourceInfo(InitTSI); 1229 Decl->setType(InitTSI->getType()); 1230 1231 // In ARC, infer lifetime. 1232 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1233 // we're doing the equivalent of fast iteration. 1234 if (SemaRef.getLangOptions().ObjCAutoRefCount && 1235 SemaRef.inferObjCARCLifetime(Decl)) 1236 Decl->setInvalidDecl(); 1237 1238 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1239 /*TypeMayContainAuto=*/false); 1240 SemaRef.FinalizeDeclaration(Decl); 1241 SemaRef.CurContext->addHiddenDecl(Decl); 1242 return false; 1243} 1244 1245/// Produce a note indicating which begin/end function was implicitly called 1246/// by a C++0x for-range statement. This is often not obvious from the code, 1247/// nor from the diagnostics produced when analysing the implicit expressions 1248/// required in a for-range statement. 1249void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1250 BeginEndFunction BEF) { 1251 CallExpr *CE = dyn_cast<CallExpr>(E); 1252 if (!CE) 1253 return; 1254 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1255 if (!D) 1256 return; 1257 SourceLocation Loc = D->getLocation(); 1258 1259 std::string Description; 1260 bool IsTemplate = false; 1261 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1262 Description = SemaRef.getTemplateArgumentBindingsText( 1263 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1264 IsTemplate = true; 1265 } 1266 1267 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1268 << BEF << IsTemplate << Description << E->getType(); 1269} 1270 1271/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1272/// given LookupResult is non-empty, it is assumed to describe a member which 1273/// will be invoked. Otherwise, the function will be found via argument 1274/// dependent lookup. 1275static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1276 SourceLocation Loc, 1277 VarDecl *Decl, 1278 BeginEndFunction BEF, 1279 const DeclarationNameInfo &NameInfo, 1280 LookupResult &MemberLookup, 1281 Expr *Range) { 1282 ExprResult CallExpr; 1283 if (!MemberLookup.empty()) { 1284 ExprResult MemberRef = 1285 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1286 /*IsPtr=*/false, CXXScopeSpec(), 1287 /*TemplateKWLoc=*/SourceLocation(), 1288 /*FirstQualifierInScope=*/0, 1289 MemberLookup, 1290 /*TemplateArgs=*/0); 1291 if (MemberRef.isInvalid()) 1292 return ExprError(); 1293 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1294 Loc, 0); 1295 if (CallExpr.isInvalid()) 1296 return ExprError(); 1297 } else { 1298 UnresolvedSet<0> FoundNames; 1299 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1300 // std is an associated namespace. 1301 UnresolvedLookupExpr *Fn = 1302 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1303 NestedNameSpecifierLoc(), NameInfo, 1304 /*NeedsADL=*/true, /*Overloaded=*/false, 1305 FoundNames.begin(), FoundNames.end(), 1306 /*LookInStdNamespace=*/true); 1307 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1308 0, /*AllowTypoCorrection=*/false); 1309 if (CallExpr.isInvalid()) { 1310 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1311 << Range->getType(); 1312 return ExprError(); 1313 } 1314 } 1315 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1316 diag::err_for_range_iter_deduction_failure)) { 1317 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1318 return ExprError(); 1319 } 1320 return CallExpr; 1321} 1322 1323} 1324 1325/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1326/// 1327/// C++0x [stmt.ranged]: 1328/// A range-based for statement is equivalent to 1329/// 1330/// { 1331/// auto && __range = range-init; 1332/// for ( auto __begin = begin-expr, 1333/// __end = end-expr; 1334/// __begin != __end; 1335/// ++__begin ) { 1336/// for-range-declaration = *__begin; 1337/// statement 1338/// } 1339/// } 1340/// 1341/// The body of the loop is not available yet, since it cannot be analysed until 1342/// we have determined the type of the for-range-declaration. 1343StmtResult 1344Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1345 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1346 SourceLocation RParenLoc) { 1347 if (!First || !Range) 1348 return StmtError(); 1349 1350 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1351 assert(DS && "first part of for range not a decl stmt"); 1352 1353 if (!DS->isSingleDecl()) { 1354 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1355 return StmtError(); 1356 } 1357 if (DS->getSingleDecl()->isInvalidDecl()) 1358 return StmtError(); 1359 1360 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1361 return StmtError(); 1362 1363 // Build auto && __range = range-init 1364 SourceLocation RangeLoc = Range->getLocStart(); 1365 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1366 Context.getAutoRRefDeductType(), 1367 "__range"); 1368 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1369 diag::err_for_range_deduction_failure)) 1370 return StmtError(); 1371 1372 // Claim the type doesn't contain auto: we've already done the checking. 1373 DeclGroupPtrTy RangeGroup = 1374 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1375 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1376 if (RangeDecl.isInvalid()) 1377 return StmtError(); 1378 1379 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1380 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1381 RParenLoc); 1382} 1383 1384/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1385StmtResult 1386Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1387 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1388 Expr *Inc, Stmt *LoopVarDecl, 1389 SourceLocation RParenLoc) { 1390 Scope *S = getCurScope(); 1391 1392 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1393 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1394 QualType RangeVarType = RangeVar->getType(); 1395 1396 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1397 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1398 1399 StmtResult BeginEndDecl = BeginEnd; 1400 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1401 1402 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1403 SourceLocation RangeLoc = RangeVar->getLocation(); 1404 1405 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1406 1407 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1408 VK_LValue, ColonLoc); 1409 if (BeginRangeRef.isInvalid()) 1410 return StmtError(); 1411 1412 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1413 VK_LValue, ColonLoc); 1414 if (EndRangeRef.isInvalid()) 1415 return StmtError(); 1416 1417 QualType AutoType = Context.getAutoDeductType(); 1418 Expr *Range = RangeVar->getInit(); 1419 if (!Range) 1420 return StmtError(); 1421 QualType RangeType = Range->getType(); 1422 1423 if (RequireCompleteType(RangeLoc, RangeType, 1424 PDiag(diag::err_for_range_incomplete_type))) 1425 return StmtError(); 1426 1427 // Build auto __begin = begin-expr, __end = end-expr. 1428 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1429 "__begin"); 1430 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1431 "__end"); 1432 1433 // Build begin-expr and end-expr and attach to __begin and __end variables. 1434 ExprResult BeginExpr, EndExpr; 1435 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1436 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1437 // __range + __bound, respectively, where __bound is the array bound. If 1438 // _RangeT is an array of unknown size or an array of incomplete type, 1439 // the program is ill-formed; 1440 1441 // begin-expr is __range. 1442 BeginExpr = BeginRangeRef; 1443 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1444 diag::err_for_range_iter_deduction_failure)) { 1445 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1446 return StmtError(); 1447 } 1448 1449 // Find the array bound. 1450 ExprResult BoundExpr; 1451 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1452 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1453 Context.getPointerDiffType(), 1454 RangeLoc)); 1455 else if (const VariableArrayType *VAT = 1456 dyn_cast<VariableArrayType>(UnqAT)) 1457 BoundExpr = VAT->getSizeExpr(); 1458 else { 1459 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1460 // UnqAT is not incomplete and Range is not type-dependent. 1461 llvm_unreachable("Unexpected array type in for-range"); 1462 } 1463 1464 // end-expr is __range + __bound. 1465 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1466 BoundExpr.get()); 1467 if (EndExpr.isInvalid()) 1468 return StmtError(); 1469 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1470 diag::err_for_range_iter_deduction_failure)) { 1471 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1472 return StmtError(); 1473 } 1474 } else { 1475 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1476 ColonLoc); 1477 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1478 ColonLoc); 1479 1480 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1481 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1482 1483 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1484 // - if _RangeT is a class type, the unqualified-ids begin and end are 1485 // looked up in the scope of class _RangeT as if by class member access 1486 // lookup (3.4.5), and if either (or both) finds at least one 1487 // declaration, begin-expr and end-expr are __range.begin() and 1488 // __range.end(), respectively; 1489 LookupQualifiedName(BeginMemberLookup, D); 1490 LookupQualifiedName(EndMemberLookup, D); 1491 1492 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1493 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1494 << RangeType << BeginMemberLookup.empty(); 1495 return StmtError(); 1496 } 1497 } else { 1498 // - otherwise, begin-expr and end-expr are begin(__range) and 1499 // end(__range), respectively, where begin and end are looked up with 1500 // argument-dependent lookup (3.4.2). For the purposes of this name 1501 // lookup, namespace std is an associated namespace. 1502 } 1503 1504 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1505 BEF_begin, BeginNameInfo, 1506 BeginMemberLookup, 1507 BeginRangeRef.get()); 1508 if (BeginExpr.isInvalid()) 1509 return StmtError(); 1510 1511 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1512 BEF_end, EndNameInfo, 1513 EndMemberLookup, EndRangeRef.get()); 1514 if (EndExpr.isInvalid()) 1515 return StmtError(); 1516 } 1517 1518 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1519 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1520 if (!Context.hasSameType(BeginType, EndType)) { 1521 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1522 << BeginType << EndType; 1523 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1524 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1525 } 1526 1527 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1528 // Claim the type doesn't contain auto: we've already done the checking. 1529 DeclGroupPtrTy BeginEndGroup = 1530 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1531 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1532 1533 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1534 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1535 VK_LValue, ColonLoc); 1536 if (BeginRef.isInvalid()) 1537 return StmtError(); 1538 1539 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1540 VK_LValue, ColonLoc); 1541 if (EndRef.isInvalid()) 1542 return StmtError(); 1543 1544 // Build and check __begin != __end expression. 1545 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1546 BeginRef.get(), EndRef.get()); 1547 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1548 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1549 if (NotEqExpr.isInvalid()) { 1550 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1551 if (!Context.hasSameType(BeginType, EndType)) 1552 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1553 return StmtError(); 1554 } 1555 1556 // Build and check ++__begin expression. 1557 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1558 VK_LValue, ColonLoc); 1559 if (BeginRef.isInvalid()) 1560 return StmtError(); 1561 1562 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1563 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1564 if (IncrExpr.isInvalid()) { 1565 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1566 return StmtError(); 1567 } 1568 1569 // Build and check *__begin expression. 1570 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1571 VK_LValue, ColonLoc); 1572 if (BeginRef.isInvalid()) 1573 return StmtError(); 1574 1575 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1576 if (DerefExpr.isInvalid()) { 1577 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1578 return StmtError(); 1579 } 1580 1581 // Attach *__begin as initializer for VD. 1582 if (!LoopVar->isInvalidDecl()) { 1583 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1584 /*TypeMayContainAuto=*/true); 1585 if (LoopVar->isInvalidDecl()) 1586 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1587 } 1588 } else { 1589 // The range is implicitly used as a placeholder when it is dependent. 1590 RangeVar->setUsed(); 1591 } 1592 1593 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1594 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1595 NotEqExpr.take(), IncrExpr.take(), 1596 LoopVarDS, /*Body=*/0, ForLoc, 1597 ColonLoc, RParenLoc)); 1598} 1599 1600/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1601/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1602/// body cannot be performed until after the type of the range variable is 1603/// determined. 1604StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1605 if (!S || !B) 1606 return StmtError(); 1607 1608 CXXForRangeStmt *ForStmt = cast<CXXForRangeStmt>(S); 1609 ForStmt->setBody(B); 1610 1611 DiagnoseEmptyStmtBody(ForStmt->getRParenLoc(), B, 1612 diag::warn_empty_range_based_for_body); 1613 1614 return S; 1615} 1616 1617StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1618 SourceLocation LabelLoc, 1619 LabelDecl *TheDecl) { 1620 getCurFunction()->setHasBranchIntoScope(); 1621 TheDecl->setUsed(); 1622 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1623} 1624 1625StmtResult 1626Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1627 Expr *E) { 1628 // Convert operand to void* 1629 if (!E->isTypeDependent()) { 1630 QualType ETy = E->getType(); 1631 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1632 ExprResult ExprRes = Owned(E); 1633 AssignConvertType ConvTy = 1634 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1635 if (ExprRes.isInvalid()) 1636 return StmtError(); 1637 E = ExprRes.take(); 1638 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1639 return StmtError(); 1640 E = MaybeCreateExprWithCleanups(E); 1641 } 1642 1643 getCurFunction()->setHasIndirectGoto(); 1644 1645 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1646} 1647 1648StmtResult 1649Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1650 Scope *S = CurScope->getContinueParent(); 1651 if (!S) { 1652 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1653 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1654 } 1655 1656 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1657} 1658 1659StmtResult 1660Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1661 Scope *S = CurScope->getBreakParent(); 1662 if (!S) { 1663 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1664 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1665 } 1666 1667 return Owned(new (Context) BreakStmt(BreakLoc)); 1668} 1669 1670/// \brief Determine whether the given expression is a candidate for 1671/// copy elision in either a return statement or a throw expression. 1672/// 1673/// \param ReturnType If we're determining the copy elision candidate for 1674/// a return statement, this is the return type of the function. If we're 1675/// determining the copy elision candidate for a throw expression, this will 1676/// be a NULL type. 1677/// 1678/// \param E The expression being returned from the function or block, or 1679/// being thrown. 1680/// 1681/// \param AllowFunctionParameter Whether we allow function parameters to 1682/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1683/// we re-use this logic to determine whether we should try to move as part of 1684/// a return or throw (which does allow function parameters). 1685/// 1686/// \returns The NRVO candidate variable, if the return statement may use the 1687/// NRVO, or NULL if there is no such candidate. 1688const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1689 Expr *E, 1690 bool AllowFunctionParameter) { 1691 QualType ExprType = E->getType(); 1692 // - in a return statement in a function with ... 1693 // ... a class return type ... 1694 if (!ReturnType.isNull()) { 1695 if (!ReturnType->isRecordType()) 1696 return 0; 1697 // ... the same cv-unqualified type as the function return type ... 1698 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1699 return 0; 1700 } 1701 1702 // ... the expression is the name of a non-volatile automatic object 1703 // (other than a function or catch-clause parameter)) ... 1704 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1705 if (!DR) 1706 return 0; 1707 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1708 if (!VD) 1709 return 0; 1710 1711 // ...object (other than a function or catch-clause parameter)... 1712 if (VD->getKind() != Decl::Var && 1713 !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) 1714 return 0; 1715 if (VD->isExceptionVariable()) return 0; 1716 1717 // ...automatic... 1718 if (!VD->hasLocalStorage()) return 0; 1719 1720 // ...non-volatile... 1721 if (VD->getType().isVolatileQualified()) return 0; 1722 if (VD->getType()->isReferenceType()) return 0; 1723 1724 // __block variables can't be allocated in a way that permits NRVO. 1725 if (VD->hasAttr<BlocksAttr>()) return 0; 1726 1727 // Variables with higher required alignment than their type's ABI 1728 // alignment cannot use NRVO. 1729 if (VD->hasAttr<AlignedAttr>() && 1730 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) 1731 return 0; 1732 1733 return VD; 1734} 1735 1736/// \brief Perform the initialization of a potentially-movable value, which 1737/// is the result of return value. 1738/// 1739/// This routine implements C++0x [class.copy]p33, which attempts to treat 1740/// returned lvalues as rvalues in certain cases (to prefer move construction), 1741/// then falls back to treating them as lvalues if that failed. 1742ExprResult 1743Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1744 const VarDecl *NRVOCandidate, 1745 QualType ResultType, 1746 Expr *Value, 1747 bool AllowNRVO) { 1748 // C++0x [class.copy]p33: 1749 // When the criteria for elision of a copy operation are met or would 1750 // be met save for the fact that the source object is a function 1751 // parameter, and the object to be copied is designated by an lvalue, 1752 // overload resolution to select the constructor for the copy is first 1753 // performed as if the object were designated by an rvalue. 1754 ExprResult Res = ExprError(); 1755 if (AllowNRVO && 1756 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 1757 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1758 Value->getType(), CK_LValueToRValue, 1759 Value, VK_XValue); 1760 1761 Expr *InitExpr = &AsRvalue; 1762 InitializationKind Kind 1763 = InitializationKind::CreateCopy(Value->getLocStart(), 1764 Value->getLocStart()); 1765 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1766 1767 // [...] If overload resolution fails, or if the type of the first 1768 // parameter of the selected constructor is not an rvalue reference 1769 // to the object's type (possibly cv-qualified), overload resolution 1770 // is performed again, considering the object as an lvalue. 1771 if (Seq) { 1772 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1773 StepEnd = Seq.step_end(); 1774 Step != StepEnd; ++Step) { 1775 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 1776 continue; 1777 1778 CXXConstructorDecl *Constructor 1779 = cast<CXXConstructorDecl>(Step->Function.Function); 1780 1781 const RValueReferenceType *RRefType 1782 = Constructor->getParamDecl(0)->getType() 1783 ->getAs<RValueReferenceType>(); 1784 1785 // If we don't meet the criteria, break out now. 1786 if (!RRefType || 1787 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1788 Context.getTypeDeclType(Constructor->getParent()))) 1789 break; 1790 1791 // Promote "AsRvalue" to the heap, since we now need this 1792 // expression node to persist. 1793 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1794 CK_LValueToRValue, Value, 0, 1795 VK_XValue); 1796 1797 // Complete type-checking the initialization of the return type 1798 // using the constructor we found. 1799 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1800 } 1801 } 1802 } 1803 1804 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1805 // above, or overload resolution failed. Either way, we need to try 1806 // (again) now with the return value expression as written. 1807 if (Res.isInvalid()) 1808 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1809 1810 return Res; 1811} 1812 1813/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements 1814/// for capturing scopes. 1815/// 1816StmtResult 1817Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1818 // If this is the first return we've seen, infer the return type. 1819 // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those 1820 // rules which allows multiple return statements. 1821 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction()); 1822 if (CurCap->HasImplicitReturnType) { 1823 QualType ReturnT; 1824 if (RetValExp && !isa<InitListExpr>(RetValExp)) { 1825 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 1826 if (Result.isInvalid()) 1827 return StmtError(); 1828 RetValExp = Result.take(); 1829 1830 if (!RetValExp->isTypeDependent()) 1831 ReturnT = RetValExp->getType(); 1832 else 1833 ReturnT = Context.DependentTy; 1834 } else { 1835 if (RetValExp) { 1836 // C++11 [expr.lambda.prim]p4 bans inferring the result from an 1837 // initializer list, because it is not an expression (even 1838 // though we represent it as one). We still deduce 'void'. 1839 Diag(ReturnLoc, diag::err_lambda_return_init_list) 1840 << RetValExp->getSourceRange(); 1841 } 1842 1843 ReturnT = Context.VoidTy; 1844 } 1845 // We require the return types to strictly match here. 1846 if (!CurCap->ReturnType.isNull() && 1847 !CurCap->ReturnType->isDependentType() && 1848 !ReturnT->isDependentType() && 1849 !Context.hasSameType(ReturnT, CurCap->ReturnType)) { 1850 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) 1851 << ReturnT << CurCap->ReturnType 1852 << (getCurLambda() != 0); 1853 return StmtError(); 1854 } 1855 CurCap->ReturnType = ReturnT; 1856 } 1857 QualType FnRetType = CurCap->ReturnType; 1858 assert(!FnRetType.isNull()); 1859 1860 if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) { 1861 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1862 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr); 1863 return StmtError(); 1864 } 1865 } else { 1866 LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CurCap); 1867 if (LSI->CallOperator->getType()->getAs<FunctionType>()->getNoReturnAttr()){ 1868 Diag(ReturnLoc, diag::err_noreturn_lambda_has_return_expr); 1869 return StmtError(); 1870 } 1871 } 1872 1873 // Otherwise, verify that this result type matches the previous one. We are 1874 // pickier with blocks than for normal functions because we don't have GCC 1875 // compatibility to worry about here. 1876 const VarDecl *NRVOCandidate = 0; 1877 if (FnRetType->isDependentType()) { 1878 // Delay processing for now. TODO: there are lots of dependent 1879 // types we can conclusively prove aren't void. 1880 } else if (FnRetType->isVoidType()) { 1881 if (RetValExp && 1882 !(getLangOptions().CPlusPlus && 1883 (RetValExp->isTypeDependent() || 1884 RetValExp->getType()->isVoidType()))) { 1885 Diag(ReturnLoc, diag::err_return_block_has_expr); 1886 RetValExp = 0; 1887 } 1888 } else if (!RetValExp) { 1889 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1890 } else if (!RetValExp->isTypeDependent()) { 1891 // we have a non-void block with an expression, continue checking 1892 1893 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1894 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1895 // function return. 1896 1897 // In C++ the return statement is handled via a copy initialization. 1898 // the C version of which boils down to CheckSingleAssignmentConstraints. 1899 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1900 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1901 FnRetType, 1902 NRVOCandidate != 0); 1903 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1904 FnRetType, RetValExp); 1905 if (Res.isInvalid()) { 1906 // FIXME: Cleanup temporaries here, anyway? 1907 return StmtError(); 1908 } 1909 RetValExp = Res.take(); 1910 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1911 } 1912 1913 if (RetValExp) { 1914 CheckImplicitConversions(RetValExp, ReturnLoc); 1915 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1916 } 1917 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 1918 NRVOCandidate); 1919 1920 // If we need to check for the named return value optimization, save the 1921 // return statement in our scope for later processing. 1922 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1923 !CurContext->isDependentContext()) 1924 FunctionScopes.back()->Returns.push_back(Result); 1925 1926 return Owned(Result); 1927} 1928 1929StmtResult 1930Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1931 // Check for unexpanded parameter packs. 1932 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 1933 return StmtError(); 1934 1935 if (isa<CapturingScopeInfo>(getCurFunction())) 1936 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp); 1937 1938 QualType FnRetType; 1939 QualType DeclaredRetType; 1940 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1941 FnRetType = FD->getResultType(); 1942 DeclaredRetType = FnRetType; 1943 if (FD->hasAttr<NoReturnAttr>() || 1944 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1945 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1946 << FD->getDeclName(); 1947 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 1948 DeclaredRetType = MD->getResultType(); 1949 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 1950 // In the implementation of a method with a related return type, the 1951 // type used to type-check the validity of return statements within the 1952 // method body is a pointer to the type of the class being implemented. 1953 FnRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 1954 FnRetType = Context.getObjCObjectPointerType(FnRetType); 1955 } else { 1956 FnRetType = DeclaredRetType; 1957 } 1958 } else // If we don't have a function/method context, bail. 1959 return StmtError(); 1960 1961 ReturnStmt *Result = 0; 1962 if (FnRetType->isVoidType()) { 1963 if (RetValExp) { 1964 if (isa<InitListExpr>(RetValExp)) { 1965 // We simply never allow init lists as the return value of void 1966 // functions. This is compatible because this was never allowed before, 1967 // so there's no legacy code to deal with. 1968 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1969 int FunctionKind = 0; 1970 if (isa<ObjCMethodDecl>(CurDecl)) 1971 FunctionKind = 1; 1972 else if (isa<CXXConstructorDecl>(CurDecl)) 1973 FunctionKind = 2; 1974 else if (isa<CXXDestructorDecl>(CurDecl)) 1975 FunctionKind = 3; 1976 1977 Diag(ReturnLoc, diag::err_return_init_list) 1978 << CurDecl->getDeclName() << FunctionKind 1979 << RetValExp->getSourceRange(); 1980 1981 // Drop the expression. 1982 RetValExp = 0; 1983 } else if (!RetValExp->isTypeDependent()) { 1984 // C99 6.8.6.4p1 (ext_ since GCC warns) 1985 unsigned D = diag::ext_return_has_expr; 1986 if (RetValExp->getType()->isVoidType()) 1987 D = diag::ext_return_has_void_expr; 1988 else { 1989 ExprResult Result = Owned(RetValExp); 1990 Result = IgnoredValueConversions(Result.take()); 1991 if (Result.isInvalid()) 1992 return StmtError(); 1993 RetValExp = Result.take(); 1994 RetValExp = ImpCastExprToType(RetValExp, 1995 Context.VoidTy, CK_ToVoid).take(); 1996 } 1997 1998 // return (some void expression); is legal in C++. 1999 if (D != diag::ext_return_has_void_expr || 2000 !getLangOptions().CPlusPlus) { 2001 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 2002 2003 int FunctionKind = 0; 2004 if (isa<ObjCMethodDecl>(CurDecl)) 2005 FunctionKind = 1; 2006 else if (isa<CXXConstructorDecl>(CurDecl)) 2007 FunctionKind = 2; 2008 else if (isa<CXXDestructorDecl>(CurDecl)) 2009 FunctionKind = 3; 2010 2011 Diag(ReturnLoc, D) 2012 << CurDecl->getDeclName() << FunctionKind 2013 << RetValExp->getSourceRange(); 2014 } 2015 } 2016 2017 if (RetValExp) { 2018 CheckImplicitConversions(RetValExp, ReturnLoc); 2019 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2020 } 2021 } 2022 2023 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 2024 } else if (!RetValExp && !FnRetType->isDependentType()) { 2025 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 2026 // C99 6.8.6.4p1 (ext_ since GCC warns) 2027 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 2028 2029 if (FunctionDecl *FD = getCurFunctionDecl()) 2030 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 2031 else 2032 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 2033 Result = new (Context) ReturnStmt(ReturnLoc); 2034 } else { 2035 const VarDecl *NRVOCandidate = 0; 2036 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 2037 // we have a non-void function with an expression, continue checking 2038 2039 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 2040 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 2041 // function return. 2042 2043 // In C++ the return statement is handled via a copy initialization, 2044 // the C version of which boils down to CheckSingleAssignmentConstraints. 2045 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 2046 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 2047 FnRetType, 2048 NRVOCandidate != 0); 2049 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 2050 FnRetType, RetValExp); 2051 if (Res.isInvalid()) { 2052 // FIXME: Cleanup temporaries here, anyway? 2053 return StmtError(); 2054 } 2055 2056 RetValExp = Res.takeAs<Expr>(); 2057 if (RetValExp) 2058 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2059 } 2060 2061 if (RetValExp) { 2062 // If we type-checked an Objective-C method's return type based 2063 // on a related return type, we may need to adjust the return 2064 // type again. Do so now. 2065 if (DeclaredRetType != FnRetType) { 2066 ExprResult result = PerformImplicitConversion(RetValExp, 2067 DeclaredRetType, 2068 AA_Returning); 2069 if (result.isInvalid()) return StmtError(); 2070 RetValExp = result.take(); 2071 } 2072 2073 CheckImplicitConversions(RetValExp, ReturnLoc); 2074 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2075 } 2076 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 2077 } 2078 2079 // If we need to check for the named return value optimization, save the 2080 // return statement in our scope for later processing. 2081 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 2082 !CurContext->isDependentContext()) 2083 FunctionScopes.back()->Returns.push_back(Result); 2084 2085 return Owned(Result); 2086} 2087 2088/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 2089/// ignore "noop" casts in places where an lvalue is required by an inline asm. 2090/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 2091/// provide a strong guidance to not use it. 2092/// 2093/// This method checks to see if the argument is an acceptable l-value and 2094/// returns false if it is a case we can handle. 2095static bool CheckAsmLValue(const Expr *E, Sema &S) { 2096 // Type dependent expressions will be checked during instantiation. 2097 if (E->isTypeDependent()) 2098 return false; 2099 2100 if (E->isLValue()) 2101 return false; // Cool, this is an lvalue. 2102 2103 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 2104 // are supposed to allow. 2105 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 2106 if (E != E2 && E2->isLValue()) { 2107 if (!S.getLangOptions().HeinousExtensions) 2108 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 2109 << E->getSourceRange(); 2110 else 2111 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 2112 << E->getSourceRange(); 2113 // Accept, even if we emitted an error diagnostic. 2114 return false; 2115 } 2116 2117 // None of the above, just randomly invalid non-lvalue. 2118 return true; 2119} 2120 2121/// isOperandMentioned - Return true if the specified operand # is mentioned 2122/// anywhere in the decomposed asm string. 2123static bool isOperandMentioned(unsigned OpNo, 2124 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2125 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2126 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2127 if (!Piece.isOperand()) continue; 2128 2129 // If this is a reference to the input and if the input was the smaller 2130 // one, then we have to reject this asm. 2131 if (Piece.getOperandNo() == OpNo) 2132 return true; 2133 } 2134 2135 return false; 2136} 2137 2138StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2139 bool IsVolatile, unsigned NumOutputs, 2140 unsigned NumInputs, IdentifierInfo **Names, 2141 MultiExprArg constraints, MultiExprArg exprs, 2142 Expr *asmString, MultiExprArg clobbers, 2143 SourceLocation RParenLoc, bool MSAsm) { 2144 unsigned NumClobbers = clobbers.size(); 2145 StringLiteral **Constraints = 2146 reinterpret_cast<StringLiteral**>(constraints.get()); 2147 Expr **Exprs = exprs.get(); 2148 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2149 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2150 2151 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2152 2153 // The parser verifies that there is a string literal here. 2154 if (!AsmString->isAscii()) 2155 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2156 << AsmString->getSourceRange()); 2157 2158 for (unsigned i = 0; i != NumOutputs; i++) { 2159 StringLiteral *Literal = Constraints[i]; 2160 if (!Literal->isAscii()) 2161 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2162 << Literal->getSourceRange()); 2163 2164 StringRef OutputName; 2165 if (Names[i]) 2166 OutputName = Names[i]->getName(); 2167 2168 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2169 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2170 return StmtError(Diag(Literal->getLocStart(), 2171 diag::err_asm_invalid_output_constraint) 2172 << Info.getConstraintStr()); 2173 2174 // Check that the output exprs are valid lvalues. 2175 Expr *OutputExpr = Exprs[i]; 2176 if (CheckAsmLValue(OutputExpr, *this)) { 2177 return StmtError(Diag(OutputExpr->getLocStart(), 2178 diag::err_asm_invalid_lvalue_in_output) 2179 << OutputExpr->getSourceRange()); 2180 } 2181 2182 OutputConstraintInfos.push_back(Info); 2183 } 2184 2185 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2186 2187 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2188 StringLiteral *Literal = Constraints[i]; 2189 if (!Literal->isAscii()) 2190 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2191 << Literal->getSourceRange()); 2192 2193 StringRef InputName; 2194 if (Names[i]) 2195 InputName = Names[i]->getName(); 2196 2197 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2198 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2199 NumOutputs, Info)) { 2200 return StmtError(Diag(Literal->getLocStart(), 2201 diag::err_asm_invalid_input_constraint) 2202 << Info.getConstraintStr()); 2203 } 2204 2205 Expr *InputExpr = Exprs[i]; 2206 2207 // Only allow void types for memory constraints. 2208 if (Info.allowsMemory() && !Info.allowsRegister()) { 2209 if (CheckAsmLValue(InputExpr, *this)) 2210 return StmtError(Diag(InputExpr->getLocStart(), 2211 diag::err_asm_invalid_lvalue_in_input) 2212 << Info.getConstraintStr() 2213 << InputExpr->getSourceRange()); 2214 } 2215 2216 if (Info.allowsRegister()) { 2217 if (InputExpr->getType()->isVoidType()) { 2218 return StmtError(Diag(InputExpr->getLocStart(), 2219 diag::err_asm_invalid_type_in_input) 2220 << InputExpr->getType() << Info.getConstraintStr() 2221 << InputExpr->getSourceRange()); 2222 } 2223 } 2224 2225 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2226 if (Result.isInvalid()) 2227 return StmtError(); 2228 2229 Exprs[i] = Result.take(); 2230 InputConstraintInfos.push_back(Info); 2231 } 2232 2233 // Check that the clobbers are valid. 2234 for (unsigned i = 0; i != NumClobbers; i++) { 2235 StringLiteral *Literal = Clobbers[i]; 2236 if (!Literal->isAscii()) 2237 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2238 << Literal->getSourceRange()); 2239 2240 StringRef Clobber = Literal->getString(); 2241 2242 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2243 return StmtError(Diag(Literal->getLocStart(), 2244 diag::err_asm_unknown_register_name) << Clobber); 2245 } 2246 2247 AsmStmt *NS = 2248 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2249 NumOutputs, NumInputs, Names, Constraints, Exprs, 2250 AsmString, NumClobbers, Clobbers, RParenLoc); 2251 // Validate the asm string, ensuring it makes sense given the operands we 2252 // have. 2253 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2254 unsigned DiagOffs; 2255 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2256 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2257 << AsmString->getSourceRange(); 2258 return StmtError(); 2259 } 2260 2261 // Validate tied input operands for type mismatches. 2262 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2263 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2264 2265 // If this is a tied constraint, verify that the output and input have 2266 // either exactly the same type, or that they are int/ptr operands with the 2267 // same size (int/long, int*/long, are ok etc). 2268 if (!Info.hasTiedOperand()) continue; 2269 2270 unsigned TiedTo = Info.getTiedOperand(); 2271 unsigned InputOpNo = i+NumOutputs; 2272 Expr *OutputExpr = Exprs[TiedTo]; 2273 Expr *InputExpr = Exprs[InputOpNo]; 2274 2275 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2276 continue; 2277 2278 QualType InTy = InputExpr->getType(); 2279 QualType OutTy = OutputExpr->getType(); 2280 if (Context.hasSameType(InTy, OutTy)) 2281 continue; // All types can be tied to themselves. 2282 2283 // Decide if the input and output are in the same domain (integer/ptr or 2284 // floating point. 2285 enum AsmDomain { 2286 AD_Int, AD_FP, AD_Other 2287 } InputDomain, OutputDomain; 2288 2289 if (InTy->isIntegerType() || InTy->isPointerType()) 2290 InputDomain = AD_Int; 2291 else if (InTy->isRealFloatingType()) 2292 InputDomain = AD_FP; 2293 else 2294 InputDomain = AD_Other; 2295 2296 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2297 OutputDomain = AD_Int; 2298 else if (OutTy->isRealFloatingType()) 2299 OutputDomain = AD_FP; 2300 else 2301 OutputDomain = AD_Other; 2302 2303 // They are ok if they are the same size and in the same domain. This 2304 // allows tying things like: 2305 // void* to int* 2306 // void* to int if they are the same size. 2307 // double to long double if they are the same size. 2308 // 2309 uint64_t OutSize = Context.getTypeSize(OutTy); 2310 uint64_t InSize = Context.getTypeSize(InTy); 2311 if (OutSize == InSize && InputDomain == OutputDomain && 2312 InputDomain != AD_Other) 2313 continue; 2314 2315 // If the smaller input/output operand is not mentioned in the asm string, 2316 // then we can promote the smaller one to a larger input and the asm string 2317 // won't notice. 2318 bool SmallerValueMentioned = false; 2319 2320 // If this is a reference to the input and if the input was the smaller 2321 // one, then we have to reject this asm. 2322 if (isOperandMentioned(InputOpNo, Pieces)) { 2323 // This is a use in the asm string of the smaller operand. Since we 2324 // codegen this by promoting to a wider value, the asm will get printed 2325 // "wrong". 2326 SmallerValueMentioned |= InSize < OutSize; 2327 } 2328 if (isOperandMentioned(TiedTo, Pieces)) { 2329 // If this is a reference to the output, and if the output is the larger 2330 // value, then it's ok because we'll promote the input to the larger type. 2331 SmallerValueMentioned |= OutSize < InSize; 2332 } 2333 2334 // If the smaller value wasn't mentioned in the asm string, and if the 2335 // output was a register, just extend the shorter one to the size of the 2336 // larger one. 2337 if (!SmallerValueMentioned && InputDomain != AD_Other && 2338 OutputConstraintInfos[TiedTo].allowsRegister()) 2339 continue; 2340 2341 // Either both of the operands were mentioned or the smaller one was 2342 // mentioned. One more special case that we'll allow: if the tied input is 2343 // integer, unmentioned, and is a constant, then we'll allow truncating it 2344 // down to the size of the destination. 2345 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2346 !isOperandMentioned(InputOpNo, Pieces) && 2347 InputExpr->isEvaluatable(Context)) { 2348 CastKind castKind = 2349 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2350 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2351 Exprs[InputOpNo] = InputExpr; 2352 NS->setInputExpr(i, InputExpr); 2353 continue; 2354 } 2355 2356 Diag(InputExpr->getLocStart(), 2357 diag::err_asm_tying_incompatible_types) 2358 << InTy << OutTy << OutputExpr->getSourceRange() 2359 << InputExpr->getSourceRange(); 2360 return StmtError(); 2361 } 2362 2363 return Owned(NS); 2364} 2365 2366StmtResult 2367Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2368 SourceLocation RParen, Decl *Parm, 2369 Stmt *Body) { 2370 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2371 if (Var && Var->isInvalidDecl()) 2372 return StmtError(); 2373 2374 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2375} 2376 2377StmtResult 2378Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2379 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2380} 2381 2382StmtResult 2383Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2384 MultiStmtArg CatchStmts, Stmt *Finally) { 2385 if (!getLangOptions().ObjCExceptions) 2386 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2387 2388 getCurFunction()->setHasBranchProtectedScope(); 2389 unsigned NumCatchStmts = CatchStmts.size(); 2390 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2391 CatchStmts.release(), 2392 NumCatchStmts, 2393 Finally)); 2394} 2395 2396StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 2397 Expr *Throw) { 2398 if (Throw) { 2399 Throw = MaybeCreateExprWithCleanups(Throw); 2400 ExprResult Result = DefaultLvalueConversion(Throw); 2401 if (Result.isInvalid()) 2402 return StmtError(); 2403 2404 Throw = Result.take(); 2405 QualType ThrowType = Throw->getType(); 2406 // Make sure the expression type is an ObjC pointer or "void *". 2407 if (!ThrowType->isDependentType() && 2408 !ThrowType->isObjCObjectPointerType()) { 2409 const PointerType *PT = ThrowType->getAs<PointerType>(); 2410 if (!PT || !PT->getPointeeType()->isVoidType()) 2411 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2412 << Throw->getType() << Throw->getSourceRange()); 2413 } 2414 } 2415 2416 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2417} 2418 2419StmtResult 2420Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2421 Scope *CurScope) { 2422 if (!getLangOptions().ObjCExceptions) 2423 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2424 2425 if (!Throw) { 2426 // @throw without an expression designates a rethrow (which much occur 2427 // in the context of an @catch clause). 2428 Scope *AtCatchParent = CurScope; 2429 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2430 AtCatchParent = AtCatchParent->getParent(); 2431 if (!AtCatchParent) 2432 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2433 } 2434 2435 return BuildObjCAtThrowStmt(AtLoc, Throw); 2436} 2437 2438ExprResult 2439Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 2440 ExprResult result = DefaultLvalueConversion(operand); 2441 if (result.isInvalid()) 2442 return ExprError(); 2443 operand = result.take(); 2444 2445 // Make sure the expression type is an ObjC pointer or "void *". 2446 QualType type = operand->getType(); 2447 if (!type->isDependentType() && 2448 !type->isObjCObjectPointerType()) { 2449 const PointerType *pointerType = type->getAs<PointerType>(); 2450 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 2451 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 2452 << type << operand->getSourceRange(); 2453 } 2454 2455 // The operand to @synchronized is a full-expression. 2456 return MaybeCreateExprWithCleanups(operand); 2457} 2458 2459StmtResult 2460Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2461 Stmt *SyncBody) { 2462 // We can't jump into or indirect-jump out of a @synchronized block. 2463 getCurFunction()->setHasBranchProtectedScope(); 2464 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2465} 2466 2467/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2468/// and creates a proper catch handler from them. 2469StmtResult 2470Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2471 Stmt *HandlerBlock) { 2472 // There's nothing to test that ActOnExceptionDecl didn't already test. 2473 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2474 cast_or_null<VarDecl>(ExDecl), 2475 HandlerBlock)); 2476} 2477 2478StmtResult 2479Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2480 getCurFunction()->setHasBranchProtectedScope(); 2481 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2482} 2483 2484namespace { 2485 2486class TypeWithHandler { 2487 QualType t; 2488 CXXCatchStmt *stmt; 2489public: 2490 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2491 : t(type), stmt(statement) {} 2492 2493 // An arbitrary order is fine as long as it places identical 2494 // types next to each other. 2495 bool operator<(const TypeWithHandler &y) const { 2496 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2497 return true; 2498 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2499 return false; 2500 else 2501 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2502 } 2503 2504 bool operator==(const TypeWithHandler& other) const { 2505 return t == other.t; 2506 } 2507 2508 CXXCatchStmt *getCatchStmt() const { return stmt; } 2509 SourceLocation getTypeSpecStartLoc() const { 2510 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2511 } 2512}; 2513 2514} 2515 2516/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2517/// handlers and creates a try statement from them. 2518StmtResult 2519Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2520 MultiStmtArg RawHandlers) { 2521 // Don't report an error if 'try' is used in system headers. 2522 if (!getLangOptions().CXXExceptions && 2523 !getSourceManager().isInSystemHeader(TryLoc)) 2524 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2525 2526 unsigned NumHandlers = RawHandlers.size(); 2527 assert(NumHandlers > 0 && 2528 "The parser shouldn't call this if there are no handlers."); 2529 Stmt **Handlers = RawHandlers.get(); 2530 2531 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2532 2533 for (unsigned i = 0; i < NumHandlers; ++i) { 2534 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2535 if (!Handler->getExceptionDecl()) { 2536 if (i < NumHandlers - 1) 2537 return StmtError(Diag(Handler->getLocStart(), 2538 diag::err_early_catch_all)); 2539 2540 continue; 2541 } 2542 2543 const QualType CaughtType = Handler->getCaughtType(); 2544 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2545 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2546 } 2547 2548 // Detect handlers for the same type as an earlier one. 2549 if (NumHandlers > 1) { 2550 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2551 2552 TypeWithHandler prev = TypesWithHandlers[0]; 2553 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2554 TypeWithHandler curr = TypesWithHandlers[i]; 2555 2556 if (curr == prev) { 2557 Diag(curr.getTypeSpecStartLoc(), 2558 diag::warn_exception_caught_by_earlier_handler) 2559 << curr.getCatchStmt()->getCaughtType().getAsString(); 2560 Diag(prev.getTypeSpecStartLoc(), 2561 diag::note_previous_exception_handler) 2562 << prev.getCatchStmt()->getCaughtType().getAsString(); 2563 } 2564 2565 prev = curr; 2566 } 2567 } 2568 2569 getCurFunction()->setHasBranchProtectedScope(); 2570 2571 // FIXME: We should detect handlers that cannot catch anything because an 2572 // earlier handler catches a superclass. Need to find a method that is not 2573 // quadratic for this. 2574 // Neither of these are explicitly forbidden, but every compiler detects them 2575 // and warns. 2576 2577 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2578 Handlers, NumHandlers)); 2579} 2580 2581StmtResult 2582Sema::ActOnSEHTryBlock(bool IsCXXTry, 2583 SourceLocation TryLoc, 2584 Stmt *TryBlock, 2585 Stmt *Handler) { 2586 assert(TryBlock && Handler); 2587 2588 getCurFunction()->setHasBranchProtectedScope(); 2589 2590 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2591} 2592 2593StmtResult 2594Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2595 Expr *FilterExpr, 2596 Stmt *Block) { 2597 assert(FilterExpr && Block); 2598 2599 if(!FilterExpr->getType()->isIntegerType()) { 2600 return StmtError(Diag(FilterExpr->getExprLoc(), 2601 diag::err_filter_expression_integral) 2602 << FilterExpr->getType()); 2603 } 2604 2605 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2606} 2607 2608StmtResult 2609Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2610 Stmt *Block) { 2611 assert(Block); 2612 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2613} 2614 2615StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 2616 bool IsIfExists, 2617 NestedNameSpecifierLoc QualifierLoc, 2618 DeclarationNameInfo NameInfo, 2619 Stmt *Nested) 2620{ 2621 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 2622 QualifierLoc, NameInfo, 2623 cast<CompoundStmt>(Nested)); 2624} 2625 2626 2627StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 2628 bool IsIfExists, 2629 CXXScopeSpec &SS, 2630 UnqualifiedId &Name, 2631 Stmt *Nested) { 2632 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 2633 SS.getWithLocInContext(Context), 2634 GetNameFromUnqualifiedId(Name), 2635 Nested); 2636} 2637