SemaStmt.cpp revision d29975fd08713eb9d1777e60536addaa62df8995
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 228StmtResult 229Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 230 MultiStmtArg elts, bool isStmtExpr) { 231 unsigned NumElts = elts.size(); 232 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 233 // If we're in C89 mode, check that we don't have any decls after stmts. If 234 // so, emit an extension diagnostic. 235 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 236 // Note that __extension__ can be around a decl. 237 unsigned i = 0; 238 // Skip over all declarations. 239 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 240 /*empty*/; 241 242 // We found the end of the list or a statement. Scan for another declstmt. 243 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 244 /*empty*/; 245 246 if (i != NumElts) { 247 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 248 Diag(D->getLocation(), diag::ext_mixed_decls_code); 249 } 250 } 251 // Warn about unused expressions in statements. 252 for (unsigned i = 0; i != NumElts; ++i) { 253 // Ignore statements that are last in a statement expression. 254 if (isStmtExpr && i == NumElts - 1) 255 continue; 256 257 DiagnoseUnusedExprResult(Elts[i]); 258 } 259 260 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 261} 262 263StmtResult 264Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 265 SourceLocation DotDotDotLoc, Expr *RHSVal, 266 SourceLocation ColonLoc) { 267 assert((LHSVal != 0) && "missing expression in case statement"); 268 269 if (getCurFunction()->SwitchStack.empty()) { 270 Diag(CaseLoc, diag::err_case_not_in_switch); 271 return StmtError(); 272 } 273 274 if (!getLangOptions().CPlusPlus0x) { 275 // C99 6.8.4.2p3: The expression shall be an integer constant. 276 // However, GCC allows any evaluatable integer expression. 277 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 278 VerifyIntegerConstantExpression(LHSVal)) 279 return StmtError(); 280 281 // GCC extension: The expression shall be an integer constant. 282 283 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 284 VerifyIntegerConstantExpression(RHSVal)) { 285 RHSVal = 0; // Recover by just forgetting about it. 286 } 287 } 288 289 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 290 ColonLoc); 291 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 292 return Owned(CS); 293} 294 295/// ActOnCaseStmtBody - This installs a statement as the body of a case. 296void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 297 DiagnoseUnusedExprResult(SubStmt); 298 299 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 300 CS->setSubStmt(SubStmt); 301} 302 303StmtResult 304Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 305 Stmt *SubStmt, Scope *CurScope) { 306 DiagnoseUnusedExprResult(SubStmt); 307 308 if (getCurFunction()->SwitchStack.empty()) { 309 Diag(DefaultLoc, diag::err_default_not_in_switch); 310 return Owned(SubStmt); 311 } 312 313 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 314 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 315 return Owned(DS); 316} 317 318StmtResult 319Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 320 SourceLocation ColonLoc, Stmt *SubStmt) { 321 322 // If the label was multiply defined, reject it now. 323 if (TheDecl->getStmt()) { 324 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 325 Diag(TheDecl->getLocation(), diag::note_previous_definition); 326 return Owned(SubStmt); 327 } 328 329 // Otherwise, things are good. Fill in the declaration and return it. 330 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 331 TheDecl->setStmt(LS); 332 if (!TheDecl->isGnuLocal()) 333 TheDecl->setLocation(IdentLoc); 334 return Owned(LS); 335} 336 337StmtResult 338Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 339 Stmt *thenStmt, SourceLocation ElseLoc, 340 Stmt *elseStmt) { 341 ExprResult CondResult(CondVal.release()); 342 343 VarDecl *ConditionVar = 0; 344 if (CondVar) { 345 ConditionVar = cast<VarDecl>(CondVar); 346 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 347 if (CondResult.isInvalid()) 348 return StmtError(); 349 } 350 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 351 if (!ConditionExpr) 352 return StmtError(); 353 354 DiagnoseUnusedExprResult(thenStmt); 355 356 // Warn if the if block has a null body without an else value. 357 // this helps prevent bugs due to typos, such as 358 // if (condition); 359 // do_stuff(); 360 // 361 if (!elseStmt) { 362 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 363 // But do not warn if the body is a macro that expands to nothing, e.g: 364 // 365 // #define CALL(x) 366 // if (condition) 367 // CALL(0); 368 // 369 if (!stmt->hasLeadingEmptyMacro()) 370 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 371 } 372 373 DiagnoseUnusedExprResult(elseStmt); 374 375 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 376 thenStmt, ElseLoc, elseStmt)); 377} 378 379/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 380/// the specified width and sign. If an overflow occurs, detect it and emit 381/// the specified diagnostic. 382void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 383 unsigned NewWidth, bool NewSign, 384 SourceLocation Loc, 385 unsigned DiagID) { 386 // Perform a conversion to the promoted condition type if needed. 387 if (NewWidth > Val.getBitWidth()) { 388 // If this is an extension, just do it. 389 Val = Val.extend(NewWidth); 390 Val.setIsSigned(NewSign); 391 392 // If the input was signed and negative and the output is 393 // unsigned, don't bother to warn: this is implementation-defined 394 // behavior. 395 // FIXME: Introduce a second, default-ignored warning for this case? 396 } else if (NewWidth < Val.getBitWidth()) { 397 // If this is a truncation, check for overflow. 398 llvm::APSInt ConvVal(Val); 399 ConvVal = ConvVal.trunc(NewWidth); 400 ConvVal.setIsSigned(NewSign); 401 ConvVal = ConvVal.extend(Val.getBitWidth()); 402 ConvVal.setIsSigned(Val.isSigned()); 403 if (ConvVal != Val) 404 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 405 406 // Regardless of whether a diagnostic was emitted, really do the 407 // truncation. 408 Val = Val.trunc(NewWidth); 409 Val.setIsSigned(NewSign); 410 } else if (NewSign != Val.isSigned()) { 411 // Convert the sign to match the sign of the condition. This can cause 412 // overflow as well: unsigned(INTMIN) 413 // We don't diagnose this overflow, because it is implementation-defined 414 // behavior. 415 // FIXME: Introduce a second, default-ignored warning for this case? 416 llvm::APSInt OldVal(Val); 417 Val.setIsSigned(NewSign); 418 } 419} 420 421namespace { 422 struct CaseCompareFunctor { 423 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 424 const llvm::APSInt &RHS) { 425 return LHS.first < RHS; 426 } 427 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 428 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 429 return LHS.first < RHS.first; 430 } 431 bool operator()(const llvm::APSInt &LHS, 432 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 433 return LHS < RHS.first; 434 } 435 }; 436} 437 438/// CmpCaseVals - Comparison predicate for sorting case values. 439/// 440static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 441 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 442 if (lhs.first < rhs.first) 443 return true; 444 445 if (lhs.first == rhs.first && 446 lhs.second->getCaseLoc().getRawEncoding() 447 < rhs.second->getCaseLoc().getRawEncoding()) 448 return true; 449 return false; 450} 451 452/// CmpEnumVals - Comparison predicate for sorting enumeration values. 453/// 454static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 455 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 456{ 457 return lhs.first < rhs.first; 458} 459 460/// EqEnumVals - Comparison preficate for uniqing enumeration values. 461/// 462static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 463 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 464{ 465 return lhs.first == rhs.first; 466} 467 468/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 469/// potentially integral-promoted expression @p expr. 470static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 471 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 472 expr = cleanups->getSubExpr(); 473 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 474 if (impcast->getCastKind() != CK_IntegralCast) break; 475 expr = impcast->getSubExpr(); 476 } 477 return expr->getType(); 478} 479 480StmtResult 481Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 482 Decl *CondVar) { 483 ExprResult CondResult; 484 485 VarDecl *ConditionVar = 0; 486 if (CondVar) { 487 ConditionVar = cast<VarDecl>(CondVar); 488 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 489 if (CondResult.isInvalid()) 490 return StmtError(); 491 492 Cond = CondResult.release(); 493 } 494 495 if (!Cond) 496 return StmtError(); 497 498 CondResult 499 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 500 PDiag(diag::err_typecheck_statement_requires_integer), 501 PDiag(diag::err_switch_incomplete_class_type) 502 << Cond->getSourceRange(), 503 PDiag(diag::err_switch_explicit_conversion), 504 PDiag(diag::note_switch_conversion), 505 PDiag(diag::err_switch_multiple_conversions), 506 PDiag(diag::note_switch_conversion), 507 PDiag(0)); 508 if (CondResult.isInvalid()) return StmtError(); 509 Cond = CondResult.take(); 510 511 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 512 CondResult = UsualUnaryConversions(Cond); 513 if (CondResult.isInvalid()) return StmtError(); 514 Cond = CondResult.take(); 515 516 if (!CondVar) { 517 CheckImplicitConversions(Cond, SwitchLoc); 518 CondResult = MaybeCreateExprWithCleanups(Cond); 519 if (CondResult.isInvalid()) 520 return StmtError(); 521 Cond = CondResult.take(); 522 } 523 524 getCurFunction()->setHasBranchIntoScope(); 525 526 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 527 getCurFunction()->SwitchStack.push_back(SS); 528 return Owned(SS); 529} 530 531static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 532 if (Val.getBitWidth() < BitWidth) 533 Val = Val.extend(BitWidth); 534 else if (Val.getBitWidth() > BitWidth) 535 Val = Val.trunc(BitWidth); 536 Val.setIsSigned(IsSigned); 537} 538 539StmtResult 540Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 541 Stmt *BodyStmt) { 542 SwitchStmt *SS = cast<SwitchStmt>(Switch); 543 assert(SS == getCurFunction()->SwitchStack.back() && 544 "switch stack missing push/pop!"); 545 546 SS->setBody(BodyStmt, SwitchLoc); 547 getCurFunction()->SwitchStack.pop_back(); 548 549 Expr *CondExpr = SS->getCond(); 550 if (!CondExpr) return StmtError(); 551 552 QualType CondType = CondExpr->getType(); 553 554 Expr *CondExprBeforePromotion = CondExpr; 555 QualType CondTypeBeforePromotion = 556 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 557 558 // C++ 6.4.2.p2: 559 // Integral promotions are performed (on the switch condition). 560 // 561 // A case value unrepresentable by the original switch condition 562 // type (before the promotion) doesn't make sense, even when it can 563 // be represented by the promoted type. Therefore we need to find 564 // the pre-promotion type of the switch condition. 565 if (!CondExpr->isTypeDependent()) { 566 // We have already converted the expression to an integral or enumeration 567 // type, when we started the switch statement. If we don't have an 568 // appropriate type now, just return an error. 569 if (!CondType->isIntegralOrEnumerationType()) 570 return StmtError(); 571 572 if (CondExpr->isKnownToHaveBooleanValue()) { 573 // switch(bool_expr) {...} is often a programmer error, e.g. 574 // switch(n && mask) { ... } // Doh - should be "n & mask". 575 // One can always use an if statement instead of switch(bool_expr). 576 Diag(SwitchLoc, diag::warn_bool_switch_condition) 577 << CondExpr->getSourceRange(); 578 } 579 } 580 581 // Get the bitwidth of the switched-on value before promotions. We must 582 // convert the integer case values to this width before comparison. 583 bool HasDependentValue 584 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 585 unsigned CondWidth 586 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 587 bool CondIsSigned 588 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 589 590 // Accumulate all of the case values in a vector so that we can sort them 591 // and detect duplicates. This vector contains the APInt for the case after 592 // it has been converted to the condition type. 593 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 594 CaseValsTy CaseVals; 595 596 // Keep track of any GNU case ranges we see. The APSInt is the low value. 597 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 598 CaseRangesTy CaseRanges; 599 600 DefaultStmt *TheDefaultStmt = 0; 601 602 bool CaseListIsErroneous = false; 603 604 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 605 SC = SC->getNextSwitchCase()) { 606 607 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 608 if (TheDefaultStmt) { 609 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 610 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 611 612 // FIXME: Remove the default statement from the switch block so that 613 // we'll return a valid AST. This requires recursing down the AST and 614 // finding it, not something we are set up to do right now. For now, 615 // just lop the entire switch stmt out of the AST. 616 CaseListIsErroneous = true; 617 } 618 TheDefaultStmt = DS; 619 620 } else { 621 CaseStmt *CS = cast<CaseStmt>(SC); 622 623 Expr *Lo = CS->getLHS(); 624 625 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 626 HasDependentValue = true; 627 break; 628 } 629 630 llvm::APSInt LoVal; 631 632 if (getLangOptions().CPlusPlus0x) { 633 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 634 // constant expression of the promoted type of the switch condition. 635 ExprResult ConvLo = 636 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue); 637 if (ConvLo.isInvalid()) { 638 CaseListIsErroneous = true; 639 continue; 640 } 641 Lo = ConvLo.take(); 642 } else { 643 // We already verified that the expression has a i-c-e value (C99 644 // 6.8.4.2p3) - get that value now. 645 LoVal = Lo->EvaluateKnownConstInt(Context); 646 647 // If the LHS is not the same type as the condition, insert an implicit 648 // cast. 649 Lo = DefaultLvalueConversion(Lo).take(); 650 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 651 } 652 653 // Convert the value to the same width/sign as the condition had prior to 654 // integral promotions. 655 // 656 // FIXME: This causes us to reject valid code: 657 // switch ((char)c) { case 256: case 0: return 0; } 658 // Here we claim there is a duplicated condition value, but there is not. 659 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 660 Lo->getLocStart(), 661 diag::warn_case_value_overflow); 662 663 CS->setLHS(Lo); 664 665 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 666 if (CS->getRHS()) { 667 if (CS->getRHS()->isTypeDependent() || 668 CS->getRHS()->isValueDependent()) { 669 HasDependentValue = true; 670 break; 671 } 672 CaseRanges.push_back(std::make_pair(LoVal, CS)); 673 } else 674 CaseVals.push_back(std::make_pair(LoVal, CS)); 675 } 676 } 677 678 if (!HasDependentValue) { 679 // If we don't have a default statement, check whether the 680 // condition is constant. 681 llvm::APSInt ConstantCondValue; 682 bool HasConstantCond = false; 683 if (!HasDependentValue && !TheDefaultStmt) { 684 HasConstantCond 685 = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context, 686 Expr::SE_AllowSideEffects); 687 assert(!HasConstantCond || 688 (ConstantCondValue.getBitWidth() == CondWidth && 689 ConstantCondValue.isSigned() == CondIsSigned)); 690 } 691 bool ShouldCheckConstantCond = HasConstantCond; 692 693 // Sort all the scalar case values so we can easily detect duplicates. 694 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 695 696 if (!CaseVals.empty()) { 697 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 698 if (ShouldCheckConstantCond && 699 CaseVals[i].first == ConstantCondValue) 700 ShouldCheckConstantCond = false; 701 702 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 703 // If we have a duplicate, report it. 704 Diag(CaseVals[i].second->getLHS()->getLocStart(), 705 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 706 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 707 diag::note_duplicate_case_prev); 708 // FIXME: We really want to remove the bogus case stmt from the 709 // substmt, but we have no way to do this right now. 710 CaseListIsErroneous = true; 711 } 712 } 713 } 714 715 // Detect duplicate case ranges, which usually don't exist at all in 716 // the first place. 717 if (!CaseRanges.empty()) { 718 // Sort all the case ranges by their low value so we can easily detect 719 // overlaps between ranges. 720 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 721 722 // Scan the ranges, computing the high values and removing empty ranges. 723 std::vector<llvm::APSInt> HiVals; 724 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 725 llvm::APSInt &LoVal = CaseRanges[i].first; 726 CaseStmt *CR = CaseRanges[i].second; 727 Expr *Hi = CR->getRHS(); 728 llvm::APSInt HiVal; 729 730 if (getLangOptions().CPlusPlus0x) { 731 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 732 // constant expression of the promoted type of the switch condition. 733 ExprResult ConvHi = 734 CheckConvertedConstantExpression(Hi, CondType, HiVal, 735 CCEK_CaseValue); 736 if (ConvHi.isInvalid()) { 737 CaseListIsErroneous = true; 738 continue; 739 } 740 Hi = ConvHi.take(); 741 } else { 742 HiVal = Hi->EvaluateKnownConstInt(Context); 743 744 // If the RHS is not the same type as the condition, insert an 745 // implicit cast. 746 Hi = DefaultLvalueConversion(Hi).take(); 747 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 748 } 749 750 // Convert the value to the same width/sign as the condition. 751 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 752 Hi->getLocStart(), 753 diag::warn_case_value_overflow); 754 755 CR->setRHS(Hi); 756 757 // If the low value is bigger than the high value, the case is empty. 758 if (LoVal > HiVal) { 759 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 760 << SourceRange(CR->getLHS()->getLocStart(), 761 Hi->getLocEnd()); 762 CaseRanges.erase(CaseRanges.begin()+i); 763 --i, --e; 764 continue; 765 } 766 767 if (ShouldCheckConstantCond && 768 LoVal <= ConstantCondValue && 769 ConstantCondValue <= HiVal) 770 ShouldCheckConstantCond = false; 771 772 HiVals.push_back(HiVal); 773 } 774 775 // Rescan the ranges, looking for overlap with singleton values and other 776 // ranges. Since the range list is sorted, we only need to compare case 777 // ranges with their neighbors. 778 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 779 llvm::APSInt &CRLo = CaseRanges[i].first; 780 llvm::APSInt &CRHi = HiVals[i]; 781 CaseStmt *CR = CaseRanges[i].second; 782 783 // Check to see whether the case range overlaps with any 784 // singleton cases. 785 CaseStmt *OverlapStmt = 0; 786 llvm::APSInt OverlapVal(32); 787 788 // Find the smallest value >= the lower bound. If I is in the 789 // case range, then we have overlap. 790 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 791 CaseVals.end(), CRLo, 792 CaseCompareFunctor()); 793 if (I != CaseVals.end() && I->first < CRHi) { 794 OverlapVal = I->first; // Found overlap with scalar. 795 OverlapStmt = I->second; 796 } 797 798 // Find the smallest value bigger than the upper bound. 799 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 800 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 801 OverlapVal = (I-1)->first; // Found overlap with scalar. 802 OverlapStmt = (I-1)->second; 803 } 804 805 // Check to see if this case stmt overlaps with the subsequent 806 // case range. 807 if (i && CRLo <= HiVals[i-1]) { 808 OverlapVal = HiVals[i-1]; // Found overlap with range. 809 OverlapStmt = CaseRanges[i-1].second; 810 } 811 812 if (OverlapStmt) { 813 // If we have a duplicate, report it. 814 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 815 << OverlapVal.toString(10); 816 Diag(OverlapStmt->getLHS()->getLocStart(), 817 diag::note_duplicate_case_prev); 818 // FIXME: We really want to remove the bogus case stmt from the 819 // substmt, but we have no way to do this right now. 820 CaseListIsErroneous = true; 821 } 822 } 823 } 824 825 // Complain if we have a constant condition and we didn't find a match. 826 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 827 // TODO: it would be nice if we printed enums as enums, chars as 828 // chars, etc. 829 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 830 << ConstantCondValue.toString(10) 831 << CondExpr->getSourceRange(); 832 } 833 834 // Check to see if switch is over an Enum and handles all of its 835 // values. We only issue a warning if there is not 'default:', but 836 // we still do the analysis to preserve this information in the AST 837 // (which can be used by flow-based analyes). 838 // 839 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 840 841 // If switch has default case, then ignore it. 842 if (!CaseListIsErroneous && !HasConstantCond && ET) { 843 const EnumDecl *ED = ET->getDecl(); 844 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 845 EnumValsTy; 846 EnumValsTy EnumVals; 847 848 // Gather all enum values, set their type and sort them, 849 // allowing easier comparison with CaseVals. 850 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 851 EDI != ED->enumerator_end(); ++EDI) { 852 llvm::APSInt Val = EDI->getInitVal(); 853 AdjustAPSInt(Val, CondWidth, CondIsSigned); 854 EnumVals.push_back(std::make_pair(Val, *EDI)); 855 } 856 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 857 EnumValsTy::iterator EIend = 858 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 859 860 // See which case values aren't in enum. 861 EnumValsTy::const_iterator EI = EnumVals.begin(); 862 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 863 CI != CaseVals.end(); CI++) { 864 while (EI != EIend && EI->first < CI->first) 865 EI++; 866 if (EI == EIend || EI->first > CI->first) 867 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 868 << ED->getDeclName(); 869 } 870 // See which of case ranges aren't in enum 871 EI = EnumVals.begin(); 872 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 873 RI != CaseRanges.end() && EI != EIend; RI++) { 874 while (EI != EIend && EI->first < RI->first) 875 EI++; 876 877 if (EI == EIend || EI->first != RI->first) { 878 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 879 << ED->getDeclName(); 880 } 881 882 llvm::APSInt Hi = 883 RI->second->getRHS()->EvaluateKnownConstInt(Context); 884 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 885 while (EI != EIend && EI->first < Hi) 886 EI++; 887 if (EI == EIend || EI->first != Hi) 888 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 889 << ED->getDeclName(); 890 } 891 892 // Check which enum vals aren't in switch 893 CaseValsTy::const_iterator CI = CaseVals.begin(); 894 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 895 bool hasCasesNotInSwitch = false; 896 897 SmallVector<DeclarationName,8> UnhandledNames; 898 899 for (EI = EnumVals.begin(); EI != EIend; EI++){ 900 // Drop unneeded case values 901 llvm::APSInt CIVal; 902 while (CI != CaseVals.end() && CI->first < EI->first) 903 CI++; 904 905 if (CI != CaseVals.end() && CI->first == EI->first) 906 continue; 907 908 // Drop unneeded case ranges 909 for (; RI != CaseRanges.end(); RI++) { 910 llvm::APSInt Hi = 911 RI->second->getRHS()->EvaluateKnownConstInt(Context); 912 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 913 if (EI->first <= Hi) 914 break; 915 } 916 917 if (RI == CaseRanges.end() || EI->first < RI->first) { 918 hasCasesNotInSwitch = true; 919 UnhandledNames.push_back(EI->second->getDeclName()); 920 } 921 } 922 923 if (TheDefaultStmt && UnhandledNames.empty()) 924 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default); 925 926 // Produce a nice diagnostic if multiple values aren't handled. 927 switch (UnhandledNames.size()) { 928 case 0: break; 929 case 1: 930 Diag(CondExpr->getExprLoc(), TheDefaultStmt 931 ? diag::warn_def_missing_case1 : diag::warn_missing_case1) 932 << UnhandledNames[0]; 933 break; 934 case 2: 935 Diag(CondExpr->getExprLoc(), TheDefaultStmt 936 ? diag::warn_def_missing_case2 : diag::warn_missing_case2) 937 << UnhandledNames[0] << UnhandledNames[1]; 938 break; 939 case 3: 940 Diag(CondExpr->getExprLoc(), TheDefaultStmt 941 ? diag::warn_def_missing_case3 : diag::warn_missing_case3) 942 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 943 break; 944 default: 945 Diag(CondExpr->getExprLoc(), TheDefaultStmt 946 ? diag::warn_def_missing_cases : diag::warn_missing_cases) 947 << (unsigned)UnhandledNames.size() 948 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 949 break; 950 } 951 952 if (!hasCasesNotInSwitch) 953 SS->setAllEnumCasesCovered(); 954 } 955 } 956 957 // FIXME: If the case list was broken is some way, we don't have a good system 958 // to patch it up. Instead, just return the whole substmt as broken. 959 if (CaseListIsErroneous) 960 return StmtError(); 961 962 return Owned(SS); 963} 964 965StmtResult 966Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 967 Decl *CondVar, Stmt *Body) { 968 ExprResult CondResult(Cond.release()); 969 970 VarDecl *ConditionVar = 0; 971 if (CondVar) { 972 ConditionVar = cast<VarDecl>(CondVar); 973 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 974 if (CondResult.isInvalid()) 975 return StmtError(); 976 } 977 Expr *ConditionExpr = CondResult.take(); 978 if (!ConditionExpr) 979 return StmtError(); 980 981 DiagnoseUnusedExprResult(Body); 982 983 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 984 Body, WhileLoc)); 985} 986 987StmtResult 988Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 989 SourceLocation WhileLoc, SourceLocation CondLParen, 990 Expr *Cond, SourceLocation CondRParen) { 991 assert(Cond && "ActOnDoStmt(): missing expression"); 992 993 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 994 if (CondResult.isInvalid() || CondResult.isInvalid()) 995 return StmtError(); 996 Cond = CondResult.take(); 997 998 CheckImplicitConversions(Cond, DoLoc); 999 CondResult = MaybeCreateExprWithCleanups(Cond); 1000 if (CondResult.isInvalid()) 1001 return StmtError(); 1002 Cond = CondResult.take(); 1003 1004 DiagnoseUnusedExprResult(Body); 1005 1006 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 1007} 1008 1009StmtResult 1010Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1011 Stmt *First, FullExprArg second, Decl *secondVar, 1012 FullExprArg third, 1013 SourceLocation RParenLoc, Stmt *Body) { 1014 if (!getLangOptions().CPlusPlus) { 1015 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 1016 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1017 // declare identifiers for objects having storage class 'auto' or 1018 // 'register'. 1019 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 1020 DI!=DE; ++DI) { 1021 VarDecl *VD = dyn_cast<VarDecl>(*DI); 1022 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 1023 VD = 0; 1024 if (VD == 0) 1025 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 1026 // FIXME: mark decl erroneous! 1027 } 1028 } 1029 } 1030 1031 ExprResult SecondResult(second.release()); 1032 VarDecl *ConditionVar = 0; 1033 if (secondVar) { 1034 ConditionVar = cast<VarDecl>(secondVar); 1035 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1036 if (SecondResult.isInvalid()) 1037 return StmtError(); 1038 } 1039 1040 Expr *Third = third.release().takeAs<Expr>(); 1041 1042 DiagnoseUnusedExprResult(First); 1043 DiagnoseUnusedExprResult(Third); 1044 DiagnoseUnusedExprResult(Body); 1045 1046 return Owned(new (Context) ForStmt(Context, First, 1047 SecondResult.take(), ConditionVar, 1048 Third, Body, ForLoc, LParenLoc, 1049 RParenLoc)); 1050} 1051 1052/// In an Objective C collection iteration statement: 1053/// for (x in y) 1054/// x can be an arbitrary l-value expression. Bind it up as a 1055/// full-expression. 1056StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1057 CheckImplicitConversions(E); 1058 ExprResult Result = MaybeCreateExprWithCleanups(E); 1059 if (Result.isInvalid()) return StmtError(); 1060 return Owned(static_cast<Stmt*>(Result.get())); 1061} 1062 1063ExprResult 1064Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1065 assert(collection); 1066 1067 // Bail out early if we've got a type-dependent expression. 1068 if (collection->isTypeDependent()) return Owned(collection); 1069 1070 // Perform normal l-value conversion. 1071 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1072 if (result.isInvalid()) 1073 return ExprError(); 1074 collection = result.take(); 1075 1076 // The operand needs to have object-pointer type. 1077 // TODO: should we do a contextual conversion? 1078 const ObjCObjectPointerType *pointerType = 1079 collection->getType()->getAs<ObjCObjectPointerType>(); 1080 if (!pointerType) 1081 return Diag(forLoc, diag::err_collection_expr_type) 1082 << collection->getType() << collection->getSourceRange(); 1083 1084 // Check that the operand provides 1085 // - countByEnumeratingWithState:objects:count: 1086 const ObjCObjectType *objectType = pointerType->getObjectType(); 1087 ObjCInterfaceDecl *iface = objectType->getInterface(); 1088 1089 // If we have a forward-declared type, we can't do this check. 1090 // Under ARC, it is an error not to have a forward-declared class. 1091 if (iface && 1092 RequireCompleteType(forLoc, QualType(objectType, 0), 1093 getLangOptions().ObjCAutoRefCount 1094 ? PDiag(diag::err_arc_collection_forward) 1095 << collection->getSourceRange() 1096 : PDiag(0))) { 1097 // Otherwise, if we have any useful type information, check that 1098 // the type declares the appropriate method. 1099 } else if (iface || !objectType->qual_empty()) { 1100 IdentifierInfo *selectorIdents[] = { 1101 &Context.Idents.get("countByEnumeratingWithState"), 1102 &Context.Idents.get("objects"), 1103 &Context.Idents.get("count") 1104 }; 1105 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1106 1107 ObjCMethodDecl *method = 0; 1108 1109 // If there's an interface, look in both the public and private APIs. 1110 if (iface) { 1111 method = iface->lookupInstanceMethod(selector); 1112 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1113 } 1114 1115 // Also check protocol qualifiers. 1116 if (!method) 1117 method = LookupMethodInQualifiedType(selector, pointerType, 1118 /*instance*/ true); 1119 1120 // If we didn't find it anywhere, give up. 1121 if (!method) { 1122 Diag(forLoc, diag::warn_collection_expr_type) 1123 << collection->getType() << selector << collection->getSourceRange(); 1124 } 1125 1126 // TODO: check for an incompatible signature? 1127 } 1128 1129 // Wrap up any cleanups in the expression. 1130 return Owned(MaybeCreateExprWithCleanups(collection)); 1131} 1132 1133StmtResult 1134Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1135 SourceLocation LParenLoc, 1136 Stmt *First, Expr *Second, 1137 SourceLocation RParenLoc, Stmt *Body) { 1138 if (First) { 1139 QualType FirstType; 1140 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1141 if (!DS->isSingleDecl()) 1142 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1143 diag::err_toomany_element_decls)); 1144 1145 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1146 FirstType = D->getType(); 1147 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1148 // declare identifiers for objects having storage class 'auto' or 1149 // 'register'. 1150 if (!D->hasLocalStorage()) 1151 return StmtError(Diag(D->getLocation(), 1152 diag::err_non_variable_decl_in_for)); 1153 } else { 1154 Expr *FirstE = cast<Expr>(First); 1155 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1156 return StmtError(Diag(First->getLocStart(), 1157 diag::err_selector_element_not_lvalue) 1158 << First->getSourceRange()); 1159 1160 FirstType = static_cast<Expr*>(First)->getType(); 1161 } 1162 if (!FirstType->isDependentType() && 1163 !FirstType->isObjCObjectPointerType() && 1164 !FirstType->isBlockPointerType()) 1165 Diag(ForLoc, diag::err_selector_element_type) 1166 << FirstType << First->getSourceRange(); 1167 } 1168 1169 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1170 ForLoc, RParenLoc)); 1171} 1172 1173namespace { 1174 1175enum BeginEndFunction { 1176 BEF_begin, 1177 BEF_end 1178}; 1179 1180/// Build a variable declaration for a for-range statement. 1181static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1182 QualType Type, const char *Name) { 1183 DeclContext *DC = SemaRef.CurContext; 1184 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1185 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1186 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1187 TInfo, SC_Auto, SC_None); 1188 Decl->setImplicit(); 1189 return Decl; 1190} 1191 1192/// Finish building a variable declaration for a for-range statement. 1193/// \return true if an error occurs. 1194static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1195 SourceLocation Loc, int diag) { 1196 // Deduce the type for the iterator variable now rather than leaving it to 1197 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1198 TypeSourceInfo *InitTSI = 0; 1199 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) || 1200 SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI) == 1201 Sema::DAR_Failed) 1202 SemaRef.Diag(Loc, diag) << Init->getType(); 1203 if (!InitTSI) { 1204 Decl->setInvalidDecl(); 1205 return true; 1206 } 1207 Decl->setTypeSourceInfo(InitTSI); 1208 Decl->setType(InitTSI->getType()); 1209 1210 // In ARC, infer lifetime. 1211 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1212 // we're doing the equivalent of fast iteration. 1213 if (SemaRef.getLangOptions().ObjCAutoRefCount && 1214 SemaRef.inferObjCARCLifetime(Decl)) 1215 Decl->setInvalidDecl(); 1216 1217 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1218 /*TypeMayContainAuto=*/false); 1219 SemaRef.FinalizeDeclaration(Decl); 1220 SemaRef.CurContext->addHiddenDecl(Decl); 1221 return false; 1222} 1223 1224/// Produce a note indicating which begin/end function was implicitly called 1225/// by a C++0x for-range statement. This is often not obvious from the code, 1226/// nor from the diagnostics produced when analysing the implicit expressions 1227/// required in a for-range statement. 1228void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1229 BeginEndFunction BEF) { 1230 CallExpr *CE = dyn_cast<CallExpr>(E); 1231 if (!CE) 1232 return; 1233 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1234 if (!D) 1235 return; 1236 SourceLocation Loc = D->getLocation(); 1237 1238 std::string Description; 1239 bool IsTemplate = false; 1240 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1241 Description = SemaRef.getTemplateArgumentBindingsText( 1242 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1243 IsTemplate = true; 1244 } 1245 1246 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1247 << BEF << IsTemplate << Description << E->getType(); 1248} 1249 1250/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1251/// given LookupResult is non-empty, it is assumed to describe a member which 1252/// will be invoked. Otherwise, the function will be found via argument 1253/// dependent lookup. 1254static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1255 SourceLocation Loc, 1256 VarDecl *Decl, 1257 BeginEndFunction BEF, 1258 const DeclarationNameInfo &NameInfo, 1259 LookupResult &MemberLookup, 1260 Expr *Range) { 1261 ExprResult CallExpr; 1262 if (!MemberLookup.empty()) { 1263 ExprResult MemberRef = 1264 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1265 /*IsPtr=*/false, CXXScopeSpec(), 1266 /*TemplateKWLoc=*/SourceLocation(), 1267 /*FirstQualifierInScope=*/0, 1268 MemberLookup, 1269 /*TemplateArgs=*/0); 1270 if (MemberRef.isInvalid()) 1271 return ExprError(); 1272 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1273 Loc, 0); 1274 if (CallExpr.isInvalid()) 1275 return ExprError(); 1276 } else { 1277 UnresolvedSet<0> FoundNames; 1278 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1279 // std is an associated namespace. 1280 UnresolvedLookupExpr *Fn = 1281 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1282 NestedNameSpecifierLoc(), NameInfo, 1283 /*NeedsADL=*/true, /*Overloaded=*/false, 1284 FoundNames.begin(), FoundNames.end(), 1285 /*LookInStdNamespace=*/true); 1286 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1287 0, /*AllowTypoCorrection=*/false); 1288 if (CallExpr.isInvalid()) { 1289 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1290 << Range->getType(); 1291 return ExprError(); 1292 } 1293 } 1294 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1295 diag::err_for_range_iter_deduction_failure)) { 1296 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1297 return ExprError(); 1298 } 1299 return CallExpr; 1300} 1301 1302} 1303 1304/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1305/// 1306/// C++0x [stmt.ranged]: 1307/// A range-based for statement is equivalent to 1308/// 1309/// { 1310/// auto && __range = range-init; 1311/// for ( auto __begin = begin-expr, 1312/// __end = end-expr; 1313/// __begin != __end; 1314/// ++__begin ) { 1315/// for-range-declaration = *__begin; 1316/// statement 1317/// } 1318/// } 1319/// 1320/// The body of the loop is not available yet, since it cannot be analysed until 1321/// we have determined the type of the for-range-declaration. 1322StmtResult 1323Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1324 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1325 SourceLocation RParenLoc) { 1326 if (!First || !Range) 1327 return StmtError(); 1328 1329 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1330 assert(DS && "first part of for range not a decl stmt"); 1331 1332 if (!DS->isSingleDecl()) { 1333 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1334 return StmtError(); 1335 } 1336 if (DS->getSingleDecl()->isInvalidDecl()) 1337 return StmtError(); 1338 1339 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1340 return StmtError(); 1341 1342 // Build auto && __range = range-init 1343 SourceLocation RangeLoc = Range->getLocStart(); 1344 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1345 Context.getAutoRRefDeductType(), 1346 "__range"); 1347 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1348 diag::err_for_range_deduction_failure)) 1349 return StmtError(); 1350 1351 // Claim the type doesn't contain auto: we've already done the checking. 1352 DeclGroupPtrTy RangeGroup = 1353 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1354 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1355 if (RangeDecl.isInvalid()) 1356 return StmtError(); 1357 1358 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1359 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1360 RParenLoc); 1361} 1362 1363/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1364StmtResult 1365Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1366 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1367 Expr *Inc, Stmt *LoopVarDecl, 1368 SourceLocation RParenLoc) { 1369 Scope *S = getCurScope(); 1370 1371 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1372 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1373 QualType RangeVarType = RangeVar->getType(); 1374 1375 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1376 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1377 1378 StmtResult BeginEndDecl = BeginEnd; 1379 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1380 1381 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1382 SourceLocation RangeLoc = RangeVar->getLocation(); 1383 1384 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1385 1386 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1387 VK_LValue, ColonLoc); 1388 if (BeginRangeRef.isInvalid()) 1389 return StmtError(); 1390 1391 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1392 VK_LValue, ColonLoc); 1393 if (EndRangeRef.isInvalid()) 1394 return StmtError(); 1395 1396 QualType AutoType = Context.getAutoDeductType(); 1397 Expr *Range = RangeVar->getInit(); 1398 if (!Range) 1399 return StmtError(); 1400 QualType RangeType = Range->getType(); 1401 1402 if (RequireCompleteType(RangeLoc, RangeType, 1403 PDiag(diag::err_for_range_incomplete_type))) 1404 return StmtError(); 1405 1406 // Build auto __begin = begin-expr, __end = end-expr. 1407 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1408 "__begin"); 1409 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1410 "__end"); 1411 1412 // Build begin-expr and end-expr and attach to __begin and __end variables. 1413 ExprResult BeginExpr, EndExpr; 1414 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1415 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1416 // __range + __bound, respectively, where __bound is the array bound. If 1417 // _RangeT is an array of unknown size or an array of incomplete type, 1418 // the program is ill-formed; 1419 1420 // begin-expr is __range. 1421 BeginExpr = BeginRangeRef; 1422 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1423 diag::err_for_range_iter_deduction_failure)) { 1424 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1425 return StmtError(); 1426 } 1427 1428 // Find the array bound. 1429 ExprResult BoundExpr; 1430 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1431 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1432 Context.getPointerDiffType(), 1433 RangeLoc)); 1434 else if (const VariableArrayType *VAT = 1435 dyn_cast<VariableArrayType>(UnqAT)) 1436 BoundExpr = VAT->getSizeExpr(); 1437 else { 1438 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1439 // UnqAT is not incomplete and Range is not type-dependent. 1440 llvm_unreachable("Unexpected array type in for-range"); 1441 } 1442 1443 // end-expr is __range + __bound. 1444 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1445 BoundExpr.get()); 1446 if (EndExpr.isInvalid()) 1447 return StmtError(); 1448 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1449 diag::err_for_range_iter_deduction_failure)) { 1450 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1451 return StmtError(); 1452 } 1453 } else { 1454 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1455 ColonLoc); 1456 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1457 ColonLoc); 1458 1459 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1460 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1461 1462 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1463 // - if _RangeT is a class type, the unqualified-ids begin and end are 1464 // looked up in the scope of class _RangeT as if by class member access 1465 // lookup (3.4.5), and if either (or both) finds at least one 1466 // declaration, begin-expr and end-expr are __range.begin() and 1467 // __range.end(), respectively; 1468 LookupQualifiedName(BeginMemberLookup, D); 1469 LookupQualifiedName(EndMemberLookup, D); 1470 1471 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1472 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1473 << RangeType << BeginMemberLookup.empty(); 1474 return StmtError(); 1475 } 1476 } else { 1477 // - otherwise, begin-expr and end-expr are begin(__range) and 1478 // end(__range), respectively, where begin and end are looked up with 1479 // argument-dependent lookup (3.4.2). For the purposes of this name 1480 // lookup, namespace std is an associated namespace. 1481 } 1482 1483 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1484 BEF_begin, BeginNameInfo, 1485 BeginMemberLookup, 1486 BeginRangeRef.get()); 1487 if (BeginExpr.isInvalid()) 1488 return StmtError(); 1489 1490 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1491 BEF_end, EndNameInfo, 1492 EndMemberLookup, EndRangeRef.get()); 1493 if (EndExpr.isInvalid()) 1494 return StmtError(); 1495 } 1496 1497 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1498 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1499 if (!Context.hasSameType(BeginType, EndType)) { 1500 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1501 << BeginType << EndType; 1502 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1503 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1504 } 1505 1506 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1507 // Claim the type doesn't contain auto: we've already done the checking. 1508 DeclGroupPtrTy BeginEndGroup = 1509 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1510 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1511 1512 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1513 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1514 VK_LValue, ColonLoc); 1515 if (BeginRef.isInvalid()) 1516 return StmtError(); 1517 1518 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1519 VK_LValue, ColonLoc); 1520 if (EndRef.isInvalid()) 1521 return StmtError(); 1522 1523 // Build and check __begin != __end expression. 1524 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1525 BeginRef.get(), EndRef.get()); 1526 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1527 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1528 if (NotEqExpr.isInvalid()) { 1529 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1530 if (!Context.hasSameType(BeginType, EndType)) 1531 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1532 return StmtError(); 1533 } 1534 1535 // Build and check ++__begin expression. 1536 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1537 VK_LValue, ColonLoc); 1538 if (BeginRef.isInvalid()) 1539 return StmtError(); 1540 1541 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1542 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1543 if (IncrExpr.isInvalid()) { 1544 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1545 return StmtError(); 1546 } 1547 1548 // Build and check *__begin expression. 1549 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1550 VK_LValue, ColonLoc); 1551 if (BeginRef.isInvalid()) 1552 return StmtError(); 1553 1554 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1555 if (DerefExpr.isInvalid()) { 1556 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1557 return StmtError(); 1558 } 1559 1560 // Attach *__begin as initializer for VD. 1561 if (!LoopVar->isInvalidDecl()) { 1562 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1563 /*TypeMayContainAuto=*/true); 1564 if (LoopVar->isInvalidDecl()) 1565 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1566 } 1567 } else { 1568 // The range is implicitly used as a placeholder when it is dependent. 1569 RangeVar->setUsed(); 1570 } 1571 1572 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1573 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1574 NotEqExpr.take(), IncrExpr.take(), 1575 LoopVarDS, /*Body=*/0, ForLoc, 1576 ColonLoc, RParenLoc)); 1577} 1578 1579/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1580/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1581/// body cannot be performed until after the type of the range variable is 1582/// determined. 1583StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1584 if (!S || !B) 1585 return StmtError(); 1586 1587 cast<CXXForRangeStmt>(S)->setBody(B); 1588 return S; 1589} 1590 1591StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1592 SourceLocation LabelLoc, 1593 LabelDecl *TheDecl) { 1594 getCurFunction()->setHasBranchIntoScope(); 1595 TheDecl->setUsed(); 1596 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1597} 1598 1599StmtResult 1600Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1601 Expr *E) { 1602 // Convert operand to void* 1603 if (!E->isTypeDependent()) { 1604 QualType ETy = E->getType(); 1605 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1606 ExprResult ExprRes = Owned(E); 1607 AssignConvertType ConvTy = 1608 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1609 if (ExprRes.isInvalid()) 1610 return StmtError(); 1611 E = ExprRes.take(); 1612 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1613 return StmtError(); 1614 E = MaybeCreateExprWithCleanups(E); 1615 } 1616 1617 getCurFunction()->setHasIndirectGoto(); 1618 1619 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1620} 1621 1622StmtResult 1623Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1624 Scope *S = CurScope->getContinueParent(); 1625 if (!S) { 1626 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1627 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1628 } 1629 1630 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1631} 1632 1633StmtResult 1634Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1635 Scope *S = CurScope->getBreakParent(); 1636 if (!S) { 1637 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1638 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1639 } 1640 1641 return Owned(new (Context) BreakStmt(BreakLoc)); 1642} 1643 1644/// \brief Determine whether the given expression is a candidate for 1645/// copy elision in either a return statement or a throw expression. 1646/// 1647/// \param ReturnType If we're determining the copy elision candidate for 1648/// a return statement, this is the return type of the function. If we're 1649/// determining the copy elision candidate for a throw expression, this will 1650/// be a NULL type. 1651/// 1652/// \param E The expression being returned from the function or block, or 1653/// being thrown. 1654/// 1655/// \param AllowFunctionParameter Whether we allow function parameters to 1656/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1657/// we re-use this logic to determine whether we should try to move as part of 1658/// a return or throw (which does allow function parameters). 1659/// 1660/// \returns The NRVO candidate variable, if the return statement may use the 1661/// NRVO, or NULL if there is no such candidate. 1662const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1663 Expr *E, 1664 bool AllowFunctionParameter) { 1665 QualType ExprType = E->getType(); 1666 // - in a return statement in a function with ... 1667 // ... a class return type ... 1668 if (!ReturnType.isNull()) { 1669 if (!ReturnType->isRecordType()) 1670 return 0; 1671 // ... the same cv-unqualified type as the function return type ... 1672 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1673 return 0; 1674 } 1675 1676 // ... the expression is the name of a non-volatile automatic object 1677 // (other than a function or catch-clause parameter)) ... 1678 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1679 if (!DR) 1680 return 0; 1681 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1682 if (!VD) 1683 return 0; 1684 1685 // ...object (other than a function or catch-clause parameter)... 1686 if (VD->getKind() != Decl::Var && 1687 !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) 1688 return 0; 1689 if (VD->isExceptionVariable()) return 0; 1690 1691 // ...automatic... 1692 if (!VD->hasLocalStorage()) return 0; 1693 1694 // ...non-volatile... 1695 if (VD->getType().isVolatileQualified()) return 0; 1696 if (VD->getType()->isReferenceType()) return 0; 1697 1698 // __block variables can't be allocated in a way that permits NRVO. 1699 if (VD->hasAttr<BlocksAttr>()) return 0; 1700 1701 // Variables with higher required alignment than their type's ABI 1702 // alignment cannot use NRVO. 1703 if (VD->hasAttr<AlignedAttr>() && 1704 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) 1705 return 0; 1706 1707 return VD; 1708} 1709 1710/// \brief Perform the initialization of a potentially-movable value, which 1711/// is the result of return value. 1712/// 1713/// This routine implements C++0x [class.copy]p33, which attempts to treat 1714/// returned lvalues as rvalues in certain cases (to prefer move construction), 1715/// then falls back to treating them as lvalues if that failed. 1716ExprResult 1717Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1718 const VarDecl *NRVOCandidate, 1719 QualType ResultType, 1720 Expr *Value, 1721 bool AllowNRVO) { 1722 // C++0x [class.copy]p33: 1723 // When the criteria for elision of a copy operation are met or would 1724 // be met save for the fact that the source object is a function 1725 // parameter, and the object to be copied is designated by an lvalue, 1726 // overload resolution to select the constructor for the copy is first 1727 // performed as if the object were designated by an rvalue. 1728 ExprResult Res = ExprError(); 1729 if (AllowNRVO && 1730 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 1731 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1732 Value->getType(), CK_LValueToRValue, 1733 Value, VK_XValue); 1734 1735 Expr *InitExpr = &AsRvalue; 1736 InitializationKind Kind 1737 = InitializationKind::CreateCopy(Value->getLocStart(), 1738 Value->getLocStart()); 1739 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1740 1741 // [...] If overload resolution fails, or if the type of the first 1742 // parameter of the selected constructor is not an rvalue reference 1743 // to the object's type (possibly cv-qualified), overload resolution 1744 // is performed again, considering the object as an lvalue. 1745 if (Seq) { 1746 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1747 StepEnd = Seq.step_end(); 1748 Step != StepEnd; ++Step) { 1749 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 1750 continue; 1751 1752 CXXConstructorDecl *Constructor 1753 = cast<CXXConstructorDecl>(Step->Function.Function); 1754 1755 const RValueReferenceType *RRefType 1756 = Constructor->getParamDecl(0)->getType() 1757 ->getAs<RValueReferenceType>(); 1758 1759 // If we don't meet the criteria, break out now. 1760 if (!RRefType || 1761 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1762 Context.getTypeDeclType(Constructor->getParent()))) 1763 break; 1764 1765 // Promote "AsRvalue" to the heap, since we now need this 1766 // expression node to persist. 1767 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1768 CK_LValueToRValue, Value, 0, 1769 VK_XValue); 1770 1771 // Complete type-checking the initialization of the return type 1772 // using the constructor we found. 1773 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1774 } 1775 } 1776 } 1777 1778 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1779 // above, or overload resolution failed. Either way, we need to try 1780 // (again) now with the return value expression as written. 1781 if (Res.isInvalid()) 1782 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1783 1784 return Res; 1785} 1786 1787/// ActOnCapScopeReturnStmt - Utility routine to type-check return statements 1788/// for capturing scopes. 1789/// 1790StmtResult 1791Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1792 // If this is the first return we've seen, infer the return type. 1793 // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those 1794 // rules which allows multiple return statements. 1795 CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction()); 1796 if (CurCap->HasImplicitReturnType) { 1797 QualType ReturnT; 1798 if (RetValExp) { 1799 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 1800 if (Result.isInvalid()) 1801 return StmtError(); 1802 RetValExp = Result.take(); 1803 1804 if (!RetValExp->isTypeDependent()) 1805 ReturnT = RetValExp->getType(); 1806 else 1807 ReturnT = Context.DependentTy; 1808 } else { 1809 ReturnT = Context.VoidTy; 1810 } 1811 // We require the return types to strictly match here. 1812 if (!CurCap->ReturnType.isNull() && 1813 !CurCap->ReturnType->isDependentType() && 1814 !ReturnT->isDependentType() && 1815 !Context.hasSameType(ReturnT, CurCap->ReturnType)) { 1816 // FIXME: Adapt diagnostic for lambdas. 1817 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) 1818 << ReturnT << CurCap->ReturnType; 1819 return StmtError(); 1820 } 1821 CurCap->ReturnType = ReturnT; 1822 } 1823 QualType FnRetType = CurCap->ReturnType; 1824 assert(!FnRetType.isNull()); 1825 1826 if (BlockScopeInfo *CurBlock = dyn_cast<BlockScopeInfo>(CurCap)) 1827 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1828 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr); 1829 return StmtError(); 1830 } 1831 // FIXME: [[noreturn]] for lambdas! 1832 1833 // Otherwise, verify that this result type matches the previous one. We are 1834 // pickier with blocks than for normal functions because we don't have GCC 1835 // compatibility to worry about here. 1836 const VarDecl *NRVOCandidate = 0; 1837 if (FnRetType->isDependentType()) { 1838 // Delay processing for now. TODO: there are lots of dependent 1839 // types we can conclusively prove aren't void. 1840 } else if (FnRetType->isVoidType()) { 1841 if (RetValExp && 1842 !(getLangOptions().CPlusPlus && 1843 (RetValExp->isTypeDependent() || 1844 RetValExp->getType()->isVoidType()))) { 1845 Diag(ReturnLoc, diag::err_return_block_has_expr); 1846 RetValExp = 0; 1847 } 1848 } else if (!RetValExp) { 1849 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1850 } else if (!RetValExp->isTypeDependent()) { 1851 // we have a non-void block with an expression, continue checking 1852 1853 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1854 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1855 // function return. 1856 1857 // In C++ the return statement is handled via a copy initialization. 1858 // the C version of which boils down to CheckSingleAssignmentConstraints. 1859 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1860 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1861 FnRetType, 1862 NRVOCandidate != 0); 1863 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1864 FnRetType, RetValExp); 1865 if (Res.isInvalid()) { 1866 // FIXME: Cleanup temporaries here, anyway? 1867 return StmtError(); 1868 } 1869 RetValExp = Res.take(); 1870 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1871 } 1872 1873 if (RetValExp) { 1874 CheckImplicitConversions(RetValExp, ReturnLoc); 1875 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1876 } 1877 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 1878 NRVOCandidate); 1879 1880 // If we need to check for the named return value optimization, save the 1881 // return statement in our scope for later processing. 1882 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1883 !CurContext->isDependentContext()) 1884 FunctionScopes.back()->Returns.push_back(Result); 1885 1886 return Owned(Result); 1887} 1888 1889StmtResult 1890Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1891 // Check for unexpanded parameter packs. 1892 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 1893 return StmtError(); 1894 1895 if (isa<CapturingScopeInfo>(getCurFunction())) 1896 return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp); 1897 1898 QualType FnRetType; 1899 QualType DeclaredRetType; 1900 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1901 FnRetType = FD->getResultType(); 1902 DeclaredRetType = FnRetType; 1903 if (FD->hasAttr<NoReturnAttr>() || 1904 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1905 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1906 << FD->getDeclName(); 1907 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 1908 DeclaredRetType = MD->getResultType(); 1909 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 1910 // In the implementation of a method with a related return type, the 1911 // type used to type-check the validity of return statements within the 1912 // method body is a pointer to the type of the class being implemented. 1913 FnRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 1914 FnRetType = Context.getObjCObjectPointerType(FnRetType); 1915 } else { 1916 FnRetType = DeclaredRetType; 1917 } 1918 } else // If we don't have a function/method context, bail. 1919 return StmtError(); 1920 1921 ReturnStmt *Result = 0; 1922 if (FnRetType->isVoidType()) { 1923 if (RetValExp) { 1924 if (!RetValExp->isTypeDependent()) { 1925 // C99 6.8.6.4p1 (ext_ since GCC warns) 1926 unsigned D = diag::ext_return_has_expr; 1927 if (RetValExp->getType()->isVoidType()) 1928 D = diag::ext_return_has_void_expr; 1929 else { 1930 ExprResult Result = Owned(RetValExp); 1931 Result = IgnoredValueConversions(Result.take()); 1932 if (Result.isInvalid()) 1933 return StmtError(); 1934 RetValExp = Result.take(); 1935 RetValExp = ImpCastExprToType(RetValExp, 1936 Context.VoidTy, CK_ToVoid).take(); 1937 } 1938 1939 // return (some void expression); is legal in C++. 1940 if (D != diag::ext_return_has_void_expr || 1941 !getLangOptions().CPlusPlus) { 1942 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1943 1944 int FunctionKind = 0; 1945 if (isa<ObjCMethodDecl>(CurDecl)) 1946 FunctionKind = 1; 1947 else if (isa<CXXConstructorDecl>(CurDecl)) 1948 FunctionKind = 2; 1949 else if (isa<CXXDestructorDecl>(CurDecl)) 1950 FunctionKind = 3; 1951 1952 Diag(ReturnLoc, D) 1953 << CurDecl->getDeclName() << FunctionKind 1954 << RetValExp->getSourceRange(); 1955 } 1956 } 1957 1958 CheckImplicitConversions(RetValExp, ReturnLoc); 1959 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1960 } 1961 1962 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1963 } else if (!RetValExp && !FnRetType->isDependentType()) { 1964 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1965 // C99 6.8.6.4p1 (ext_ since GCC warns) 1966 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1967 1968 if (FunctionDecl *FD = getCurFunctionDecl()) 1969 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1970 else 1971 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1972 Result = new (Context) ReturnStmt(ReturnLoc); 1973 } else { 1974 const VarDecl *NRVOCandidate = 0; 1975 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1976 // we have a non-void function with an expression, continue checking 1977 1978 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1979 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1980 // function return. 1981 1982 // In C++ the return statement is handled via a copy initialization, 1983 // the C version of which boils down to CheckSingleAssignmentConstraints. 1984 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1985 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1986 FnRetType, 1987 NRVOCandidate != 0); 1988 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1989 FnRetType, RetValExp); 1990 if (Res.isInvalid()) { 1991 // FIXME: Cleanup temporaries here, anyway? 1992 return StmtError(); 1993 } 1994 1995 RetValExp = Res.takeAs<Expr>(); 1996 if (RetValExp) 1997 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1998 } 1999 2000 if (RetValExp) { 2001 // If we type-checked an Objective-C method's return type based 2002 // on a related return type, we may need to adjust the return 2003 // type again. Do so now. 2004 if (DeclaredRetType != FnRetType) { 2005 ExprResult result = PerformImplicitConversion(RetValExp, 2006 DeclaredRetType, 2007 AA_Returning); 2008 if (result.isInvalid()) return StmtError(); 2009 RetValExp = result.take(); 2010 } 2011 2012 CheckImplicitConversions(RetValExp, ReturnLoc); 2013 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2014 } 2015 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 2016 } 2017 2018 // If we need to check for the named return value optimization, save the 2019 // return statement in our scope for later processing. 2020 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 2021 !CurContext->isDependentContext()) 2022 FunctionScopes.back()->Returns.push_back(Result); 2023 2024 return Owned(Result); 2025} 2026 2027/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 2028/// ignore "noop" casts in places where an lvalue is required by an inline asm. 2029/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 2030/// provide a strong guidance to not use it. 2031/// 2032/// This method checks to see if the argument is an acceptable l-value and 2033/// returns false if it is a case we can handle. 2034static bool CheckAsmLValue(const Expr *E, Sema &S) { 2035 // Type dependent expressions will be checked during instantiation. 2036 if (E->isTypeDependent()) 2037 return false; 2038 2039 if (E->isLValue()) 2040 return false; // Cool, this is an lvalue. 2041 2042 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 2043 // are supposed to allow. 2044 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 2045 if (E != E2 && E2->isLValue()) { 2046 if (!S.getLangOptions().HeinousExtensions) 2047 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 2048 << E->getSourceRange(); 2049 else 2050 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 2051 << E->getSourceRange(); 2052 // Accept, even if we emitted an error diagnostic. 2053 return false; 2054 } 2055 2056 // None of the above, just randomly invalid non-lvalue. 2057 return true; 2058} 2059 2060/// isOperandMentioned - Return true if the specified operand # is mentioned 2061/// anywhere in the decomposed asm string. 2062static bool isOperandMentioned(unsigned OpNo, 2063 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2064 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2065 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2066 if (!Piece.isOperand()) continue; 2067 2068 // If this is a reference to the input and if the input was the smaller 2069 // one, then we have to reject this asm. 2070 if (Piece.getOperandNo() == OpNo) 2071 return true; 2072 } 2073 2074 return false; 2075} 2076 2077StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2078 bool IsVolatile, unsigned NumOutputs, 2079 unsigned NumInputs, IdentifierInfo **Names, 2080 MultiExprArg constraints, MultiExprArg exprs, 2081 Expr *asmString, MultiExprArg clobbers, 2082 SourceLocation RParenLoc, bool MSAsm) { 2083 unsigned NumClobbers = clobbers.size(); 2084 StringLiteral **Constraints = 2085 reinterpret_cast<StringLiteral**>(constraints.get()); 2086 Expr **Exprs = exprs.get(); 2087 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2088 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2089 2090 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2091 2092 // The parser verifies that there is a string literal here. 2093 if (!AsmString->isAscii()) 2094 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2095 << AsmString->getSourceRange()); 2096 2097 for (unsigned i = 0; i != NumOutputs; i++) { 2098 StringLiteral *Literal = Constraints[i]; 2099 if (!Literal->isAscii()) 2100 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2101 << Literal->getSourceRange()); 2102 2103 StringRef OutputName; 2104 if (Names[i]) 2105 OutputName = Names[i]->getName(); 2106 2107 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2108 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2109 return StmtError(Diag(Literal->getLocStart(), 2110 diag::err_asm_invalid_output_constraint) 2111 << Info.getConstraintStr()); 2112 2113 // Check that the output exprs are valid lvalues. 2114 Expr *OutputExpr = Exprs[i]; 2115 if (CheckAsmLValue(OutputExpr, *this)) { 2116 return StmtError(Diag(OutputExpr->getLocStart(), 2117 diag::err_asm_invalid_lvalue_in_output) 2118 << OutputExpr->getSourceRange()); 2119 } 2120 2121 OutputConstraintInfos.push_back(Info); 2122 } 2123 2124 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2125 2126 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2127 StringLiteral *Literal = Constraints[i]; 2128 if (!Literal->isAscii()) 2129 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2130 << Literal->getSourceRange()); 2131 2132 StringRef InputName; 2133 if (Names[i]) 2134 InputName = Names[i]->getName(); 2135 2136 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2137 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2138 NumOutputs, Info)) { 2139 return StmtError(Diag(Literal->getLocStart(), 2140 diag::err_asm_invalid_input_constraint) 2141 << Info.getConstraintStr()); 2142 } 2143 2144 Expr *InputExpr = Exprs[i]; 2145 2146 // Only allow void types for memory constraints. 2147 if (Info.allowsMemory() && !Info.allowsRegister()) { 2148 if (CheckAsmLValue(InputExpr, *this)) 2149 return StmtError(Diag(InputExpr->getLocStart(), 2150 diag::err_asm_invalid_lvalue_in_input) 2151 << Info.getConstraintStr() 2152 << InputExpr->getSourceRange()); 2153 } 2154 2155 if (Info.allowsRegister()) { 2156 if (InputExpr->getType()->isVoidType()) { 2157 return StmtError(Diag(InputExpr->getLocStart(), 2158 diag::err_asm_invalid_type_in_input) 2159 << InputExpr->getType() << Info.getConstraintStr() 2160 << InputExpr->getSourceRange()); 2161 } 2162 } 2163 2164 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2165 if (Result.isInvalid()) 2166 return StmtError(); 2167 2168 Exprs[i] = Result.take(); 2169 InputConstraintInfos.push_back(Info); 2170 } 2171 2172 // Check that the clobbers are valid. 2173 for (unsigned i = 0; i != NumClobbers; i++) { 2174 StringLiteral *Literal = Clobbers[i]; 2175 if (!Literal->isAscii()) 2176 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2177 << Literal->getSourceRange()); 2178 2179 StringRef Clobber = Literal->getString(); 2180 2181 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2182 return StmtError(Diag(Literal->getLocStart(), 2183 diag::err_asm_unknown_register_name) << Clobber); 2184 } 2185 2186 AsmStmt *NS = 2187 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2188 NumOutputs, NumInputs, Names, Constraints, Exprs, 2189 AsmString, NumClobbers, Clobbers, RParenLoc); 2190 // Validate the asm string, ensuring it makes sense given the operands we 2191 // have. 2192 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2193 unsigned DiagOffs; 2194 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2195 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2196 << AsmString->getSourceRange(); 2197 return StmtError(); 2198 } 2199 2200 // Validate tied input operands for type mismatches. 2201 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2202 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2203 2204 // If this is a tied constraint, verify that the output and input have 2205 // either exactly the same type, or that they are int/ptr operands with the 2206 // same size (int/long, int*/long, are ok etc). 2207 if (!Info.hasTiedOperand()) continue; 2208 2209 unsigned TiedTo = Info.getTiedOperand(); 2210 unsigned InputOpNo = i+NumOutputs; 2211 Expr *OutputExpr = Exprs[TiedTo]; 2212 Expr *InputExpr = Exprs[InputOpNo]; 2213 2214 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2215 continue; 2216 2217 QualType InTy = InputExpr->getType(); 2218 QualType OutTy = OutputExpr->getType(); 2219 if (Context.hasSameType(InTy, OutTy)) 2220 continue; // All types can be tied to themselves. 2221 2222 // Decide if the input and output are in the same domain (integer/ptr or 2223 // floating point. 2224 enum AsmDomain { 2225 AD_Int, AD_FP, AD_Other 2226 } InputDomain, OutputDomain; 2227 2228 if (InTy->isIntegerType() || InTy->isPointerType()) 2229 InputDomain = AD_Int; 2230 else if (InTy->isRealFloatingType()) 2231 InputDomain = AD_FP; 2232 else 2233 InputDomain = AD_Other; 2234 2235 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2236 OutputDomain = AD_Int; 2237 else if (OutTy->isRealFloatingType()) 2238 OutputDomain = AD_FP; 2239 else 2240 OutputDomain = AD_Other; 2241 2242 // They are ok if they are the same size and in the same domain. This 2243 // allows tying things like: 2244 // void* to int* 2245 // void* to int if they are the same size. 2246 // double to long double if they are the same size. 2247 // 2248 uint64_t OutSize = Context.getTypeSize(OutTy); 2249 uint64_t InSize = Context.getTypeSize(InTy); 2250 if (OutSize == InSize && InputDomain == OutputDomain && 2251 InputDomain != AD_Other) 2252 continue; 2253 2254 // If the smaller input/output operand is not mentioned in the asm string, 2255 // then we can promote the smaller one to a larger input and the asm string 2256 // won't notice. 2257 bool SmallerValueMentioned = false; 2258 2259 // If this is a reference to the input and if the input was the smaller 2260 // one, then we have to reject this asm. 2261 if (isOperandMentioned(InputOpNo, Pieces)) { 2262 // This is a use in the asm string of the smaller operand. Since we 2263 // codegen this by promoting to a wider value, the asm will get printed 2264 // "wrong". 2265 SmallerValueMentioned |= InSize < OutSize; 2266 } 2267 if (isOperandMentioned(TiedTo, Pieces)) { 2268 // If this is a reference to the output, and if the output is the larger 2269 // value, then it's ok because we'll promote the input to the larger type. 2270 SmallerValueMentioned |= OutSize < InSize; 2271 } 2272 2273 // If the smaller value wasn't mentioned in the asm string, and if the 2274 // output was a register, just extend the shorter one to the size of the 2275 // larger one. 2276 if (!SmallerValueMentioned && InputDomain != AD_Other && 2277 OutputConstraintInfos[TiedTo].allowsRegister()) 2278 continue; 2279 2280 // Either both of the operands were mentioned or the smaller one was 2281 // mentioned. One more special case that we'll allow: if the tied input is 2282 // integer, unmentioned, and is a constant, then we'll allow truncating it 2283 // down to the size of the destination. 2284 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2285 !isOperandMentioned(InputOpNo, Pieces) && 2286 InputExpr->isEvaluatable(Context)) { 2287 CastKind castKind = 2288 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2289 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2290 Exprs[InputOpNo] = InputExpr; 2291 NS->setInputExpr(i, InputExpr); 2292 continue; 2293 } 2294 2295 Diag(InputExpr->getLocStart(), 2296 diag::err_asm_tying_incompatible_types) 2297 << InTy << OutTy << OutputExpr->getSourceRange() 2298 << InputExpr->getSourceRange(); 2299 return StmtError(); 2300 } 2301 2302 return Owned(NS); 2303} 2304 2305StmtResult 2306Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2307 SourceLocation RParen, Decl *Parm, 2308 Stmt *Body) { 2309 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2310 if (Var && Var->isInvalidDecl()) 2311 return StmtError(); 2312 2313 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2314} 2315 2316StmtResult 2317Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2318 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2319} 2320 2321StmtResult 2322Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2323 MultiStmtArg CatchStmts, Stmt *Finally) { 2324 if (!getLangOptions().ObjCExceptions) 2325 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2326 2327 getCurFunction()->setHasBranchProtectedScope(); 2328 unsigned NumCatchStmts = CatchStmts.size(); 2329 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2330 CatchStmts.release(), 2331 NumCatchStmts, 2332 Finally)); 2333} 2334 2335StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 2336 Expr *Throw) { 2337 if (Throw) { 2338 Throw = MaybeCreateExprWithCleanups(Throw); 2339 ExprResult Result = DefaultLvalueConversion(Throw); 2340 if (Result.isInvalid()) 2341 return StmtError(); 2342 2343 Throw = Result.take(); 2344 QualType ThrowType = Throw->getType(); 2345 // Make sure the expression type is an ObjC pointer or "void *". 2346 if (!ThrowType->isDependentType() && 2347 !ThrowType->isObjCObjectPointerType()) { 2348 const PointerType *PT = ThrowType->getAs<PointerType>(); 2349 if (!PT || !PT->getPointeeType()->isVoidType()) 2350 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2351 << Throw->getType() << Throw->getSourceRange()); 2352 } 2353 } 2354 2355 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2356} 2357 2358StmtResult 2359Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2360 Scope *CurScope) { 2361 if (!getLangOptions().ObjCExceptions) 2362 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2363 2364 if (!Throw) { 2365 // @throw without an expression designates a rethrow (which much occur 2366 // in the context of an @catch clause). 2367 Scope *AtCatchParent = CurScope; 2368 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2369 AtCatchParent = AtCatchParent->getParent(); 2370 if (!AtCatchParent) 2371 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2372 } 2373 2374 return BuildObjCAtThrowStmt(AtLoc, Throw); 2375} 2376 2377ExprResult 2378Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 2379 ExprResult result = DefaultLvalueConversion(operand); 2380 if (result.isInvalid()) 2381 return ExprError(); 2382 operand = result.take(); 2383 2384 // Make sure the expression type is an ObjC pointer or "void *". 2385 QualType type = operand->getType(); 2386 if (!type->isDependentType() && 2387 !type->isObjCObjectPointerType()) { 2388 const PointerType *pointerType = type->getAs<PointerType>(); 2389 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 2390 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 2391 << type << operand->getSourceRange(); 2392 } 2393 2394 // The operand to @synchronized is a full-expression. 2395 return MaybeCreateExprWithCleanups(operand); 2396} 2397 2398StmtResult 2399Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2400 Stmt *SyncBody) { 2401 // We can't jump into or indirect-jump out of a @synchronized block. 2402 getCurFunction()->setHasBranchProtectedScope(); 2403 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2404} 2405 2406/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2407/// and creates a proper catch handler from them. 2408StmtResult 2409Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2410 Stmt *HandlerBlock) { 2411 // There's nothing to test that ActOnExceptionDecl didn't already test. 2412 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2413 cast_or_null<VarDecl>(ExDecl), 2414 HandlerBlock)); 2415} 2416 2417StmtResult 2418Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2419 getCurFunction()->setHasBranchProtectedScope(); 2420 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2421} 2422 2423namespace { 2424 2425class TypeWithHandler { 2426 QualType t; 2427 CXXCatchStmt *stmt; 2428public: 2429 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2430 : t(type), stmt(statement) {} 2431 2432 // An arbitrary order is fine as long as it places identical 2433 // types next to each other. 2434 bool operator<(const TypeWithHandler &y) const { 2435 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2436 return true; 2437 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2438 return false; 2439 else 2440 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2441 } 2442 2443 bool operator==(const TypeWithHandler& other) const { 2444 return t == other.t; 2445 } 2446 2447 CXXCatchStmt *getCatchStmt() const { return stmt; } 2448 SourceLocation getTypeSpecStartLoc() const { 2449 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2450 } 2451}; 2452 2453} 2454 2455/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2456/// handlers and creates a try statement from them. 2457StmtResult 2458Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2459 MultiStmtArg RawHandlers) { 2460 // Don't report an error if 'try' is used in system headers. 2461 if (!getLangOptions().CXXExceptions && 2462 !getSourceManager().isInSystemHeader(TryLoc)) 2463 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2464 2465 unsigned NumHandlers = RawHandlers.size(); 2466 assert(NumHandlers > 0 && 2467 "The parser shouldn't call this if there are no handlers."); 2468 Stmt **Handlers = RawHandlers.get(); 2469 2470 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2471 2472 for (unsigned i = 0; i < NumHandlers; ++i) { 2473 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2474 if (!Handler->getExceptionDecl()) { 2475 if (i < NumHandlers - 1) 2476 return StmtError(Diag(Handler->getLocStart(), 2477 diag::err_early_catch_all)); 2478 2479 continue; 2480 } 2481 2482 const QualType CaughtType = Handler->getCaughtType(); 2483 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2484 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2485 } 2486 2487 // Detect handlers for the same type as an earlier one. 2488 if (NumHandlers > 1) { 2489 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2490 2491 TypeWithHandler prev = TypesWithHandlers[0]; 2492 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2493 TypeWithHandler curr = TypesWithHandlers[i]; 2494 2495 if (curr == prev) { 2496 Diag(curr.getTypeSpecStartLoc(), 2497 diag::warn_exception_caught_by_earlier_handler) 2498 << curr.getCatchStmt()->getCaughtType().getAsString(); 2499 Diag(prev.getTypeSpecStartLoc(), 2500 diag::note_previous_exception_handler) 2501 << prev.getCatchStmt()->getCaughtType().getAsString(); 2502 } 2503 2504 prev = curr; 2505 } 2506 } 2507 2508 getCurFunction()->setHasBranchProtectedScope(); 2509 2510 // FIXME: We should detect handlers that cannot catch anything because an 2511 // earlier handler catches a superclass. Need to find a method that is not 2512 // quadratic for this. 2513 // Neither of these are explicitly forbidden, but every compiler detects them 2514 // and warns. 2515 2516 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2517 Handlers, NumHandlers)); 2518} 2519 2520StmtResult 2521Sema::ActOnSEHTryBlock(bool IsCXXTry, 2522 SourceLocation TryLoc, 2523 Stmt *TryBlock, 2524 Stmt *Handler) { 2525 assert(TryBlock && Handler); 2526 2527 getCurFunction()->setHasBranchProtectedScope(); 2528 2529 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2530} 2531 2532StmtResult 2533Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2534 Expr *FilterExpr, 2535 Stmt *Block) { 2536 assert(FilterExpr && Block); 2537 2538 if(!FilterExpr->getType()->isIntegerType()) { 2539 return StmtError(Diag(FilterExpr->getExprLoc(), 2540 diag::err_filter_expression_integral) 2541 << FilterExpr->getType()); 2542 } 2543 2544 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2545} 2546 2547StmtResult 2548Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2549 Stmt *Block) { 2550 assert(Block); 2551 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2552} 2553 2554StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 2555 bool IsIfExists, 2556 NestedNameSpecifierLoc QualifierLoc, 2557 DeclarationNameInfo NameInfo, 2558 Stmt *Nested) 2559{ 2560 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 2561 QualifierLoc, NameInfo, 2562 cast<CompoundStmt>(Nested)); 2563} 2564 2565 2566StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 2567 bool IsIfExists, 2568 CXXScopeSpec &SS, 2569 UnqualifiedId &Name, 2570 Stmt *Nested) { 2571 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 2572 SS.getWithLocInContext(Context), 2573 GetNameFromUnqualifiedId(Name), 2574 Nested); 2575} 2576