SemaStmt.cpp revision 1417646ef5470549b2d889b5eb1663cca5c0a3e6
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/APValue.h" 20#include "clang/AST/ASTContext.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 (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 156 return; 157 158 // Okay, we have an unused result. Depending on what the base expression is, 159 // we might want to make a more specific diagnostic. Check for one of these 160 // cases now. 161 unsigned DiagID = diag::warn_unused_expr; 162 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 163 E = Temps->getSubExpr(); 164 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 165 E = TempExpr->getSubExpr(); 166 167 if (DiagnoseUnusedComparison(*this, E)) 168 return; 169 170 E = E->IgnoreParenImpCasts(); 171 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 172 if (E->getType()->isVoidType()) 173 return; 174 175 // If the callee has attribute pure, const, or warn_unused_result, warn with 176 // a more specific message to make it clear what is happening. 177 if (const Decl *FD = CE->getCalleeDecl()) { 178 if (FD->getAttr<WarnUnusedResultAttr>()) { 179 Diag(Loc, diag::warn_unused_result) << R1 << R2; 180 return; 181 } 182 if (FD->getAttr<PureAttr>()) { 183 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 184 return; 185 } 186 if (FD->getAttr<ConstAttr>()) { 187 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 188 return; 189 } 190 } 191 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 192 if (getLangOptions().ObjCAutoRefCount && ME->isDelegateInitCall()) { 193 Diag(Loc, diag::err_arc_unused_init_message) << R1; 194 return; 195 } 196 const ObjCMethodDecl *MD = ME->getMethodDecl(); 197 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 198 Diag(Loc, diag::warn_unused_result) << R1 << R2; 199 return; 200 } 201 } else if (isa<ObjCPropertyRefExpr>(E)) { 202 DiagID = diag::warn_unused_property_expr; 203 } else if (const CXXFunctionalCastExpr *FC 204 = dyn_cast<CXXFunctionalCastExpr>(E)) { 205 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 206 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 207 return; 208 } 209 // Diagnose "(void*) blah" as a typo for "(void) blah". 210 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 211 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 212 QualType T = TI->getType(); 213 214 // We really do want to use the non-canonical type here. 215 if (T == Context.VoidPtrTy) { 216 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 217 218 Diag(Loc, diag::warn_unused_voidptr) 219 << FixItHint::CreateRemoval(TL.getStarLoc()); 220 return; 221 } 222 } 223 224 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 225} 226 227StmtResult 228Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 229 MultiStmtArg elts, bool isStmtExpr) { 230 unsigned NumElts = elts.size(); 231 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 232 // If we're in C89 mode, check that we don't have any decls after stmts. If 233 // so, emit an extension diagnostic. 234 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 235 // Note that __extension__ can be around a decl. 236 unsigned i = 0; 237 // Skip over all declarations. 238 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 239 /*empty*/; 240 241 // We found the end of the list or a statement. Scan for another declstmt. 242 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 243 /*empty*/; 244 245 if (i != NumElts) { 246 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 247 Diag(D->getLocation(), diag::ext_mixed_decls_code); 248 } 249 } 250 // Warn about unused expressions in statements. 251 for (unsigned i = 0; i != NumElts; ++i) { 252 // Ignore statements that are last in a statement expression. 253 if (isStmtExpr && i == NumElts - 1) 254 continue; 255 256 DiagnoseUnusedExprResult(Elts[i]); 257 } 258 259 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 260} 261 262StmtResult 263Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 264 SourceLocation DotDotDotLoc, Expr *RHSVal, 265 SourceLocation ColonLoc) { 266 assert((LHSVal != 0) && "missing expression in case statement"); 267 268 // C99 6.8.4.2p3: The expression shall be an integer constant. 269 // However, GCC allows any evaluatable integer expression. 270 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 271 VerifyIntegerConstantExpression(LHSVal)) 272 return StmtError(); 273 274 // GCC extension: The expression shall be an integer constant. 275 276 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 277 VerifyIntegerConstantExpression(RHSVal)) { 278 RHSVal = 0; // Recover by just forgetting about it. 279 } 280 281 if (getCurFunction()->SwitchStack.empty()) { 282 Diag(CaseLoc, diag::err_case_not_in_switch); 283 return StmtError(); 284 } 285 286 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 287 ColonLoc); 288 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 289 return Owned(CS); 290} 291 292/// ActOnCaseStmtBody - This installs a statement as the body of a case. 293void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 294 DiagnoseUnusedExprResult(SubStmt); 295 296 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 297 CS->setSubStmt(SubStmt); 298} 299 300StmtResult 301Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 302 Stmt *SubStmt, Scope *CurScope) { 303 DiagnoseUnusedExprResult(SubStmt); 304 305 if (getCurFunction()->SwitchStack.empty()) { 306 Diag(DefaultLoc, diag::err_default_not_in_switch); 307 return Owned(SubStmt); 308 } 309 310 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 311 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 312 return Owned(DS); 313} 314 315StmtResult 316Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 317 SourceLocation ColonLoc, Stmt *SubStmt) { 318 319 // If the label was multiply defined, reject it now. 320 if (TheDecl->getStmt()) { 321 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 322 Diag(TheDecl->getLocation(), diag::note_previous_definition); 323 return Owned(SubStmt); 324 } 325 326 // Otherwise, things are good. Fill in the declaration and return it. 327 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 328 TheDecl->setStmt(LS); 329 if (!TheDecl->isGnuLocal()) 330 TheDecl->setLocation(IdentLoc); 331 return Owned(LS); 332} 333 334StmtResult 335Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 336 Stmt *thenStmt, SourceLocation ElseLoc, 337 Stmt *elseStmt) { 338 ExprResult CondResult(CondVal.release()); 339 340 VarDecl *ConditionVar = 0; 341 if (CondVar) { 342 ConditionVar = cast<VarDecl>(CondVar); 343 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 344 if (CondResult.isInvalid()) 345 return StmtError(); 346 } 347 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 348 if (!ConditionExpr) 349 return StmtError(); 350 351 DiagnoseUnusedExprResult(thenStmt); 352 353 // Warn if the if block has a null body without an else value. 354 // this helps prevent bugs due to typos, such as 355 // if (condition); 356 // do_stuff(); 357 // 358 if (!elseStmt) { 359 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 360 // But do not warn if the body is a macro that expands to nothing, e.g: 361 // 362 // #define CALL(x) 363 // if (condition) 364 // CALL(0); 365 // 366 if (!stmt->hasLeadingEmptyMacro()) 367 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 368 } 369 370 DiagnoseUnusedExprResult(elseStmt); 371 372 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 373 thenStmt, ElseLoc, elseStmt)); 374} 375 376/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 377/// the specified width and sign. If an overflow occurs, detect it and emit 378/// the specified diagnostic. 379void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 380 unsigned NewWidth, bool NewSign, 381 SourceLocation Loc, 382 unsigned DiagID) { 383 // Perform a conversion to the promoted condition type if needed. 384 if (NewWidth > Val.getBitWidth()) { 385 // If this is an extension, just do it. 386 Val = Val.extend(NewWidth); 387 Val.setIsSigned(NewSign); 388 389 // If the input was signed and negative and the output is 390 // unsigned, don't bother to warn: this is implementation-defined 391 // behavior. 392 // FIXME: Introduce a second, default-ignored warning for this case? 393 } else if (NewWidth < Val.getBitWidth()) { 394 // If this is a truncation, check for overflow. 395 llvm::APSInt ConvVal(Val); 396 ConvVal = ConvVal.trunc(NewWidth); 397 ConvVal.setIsSigned(NewSign); 398 ConvVal = ConvVal.extend(Val.getBitWidth()); 399 ConvVal.setIsSigned(Val.isSigned()); 400 if (ConvVal != Val) 401 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 402 403 // Regardless of whether a diagnostic was emitted, really do the 404 // truncation. 405 Val = Val.trunc(NewWidth); 406 Val.setIsSigned(NewSign); 407 } else if (NewSign != Val.isSigned()) { 408 // Convert the sign to match the sign of the condition. This can cause 409 // overflow as well: unsigned(INTMIN) 410 // We don't diagnose this overflow, because it is implementation-defined 411 // behavior. 412 // FIXME: Introduce a second, default-ignored warning for this case? 413 llvm::APSInt OldVal(Val); 414 Val.setIsSigned(NewSign); 415 } 416} 417 418namespace { 419 struct CaseCompareFunctor { 420 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 421 const llvm::APSInt &RHS) { 422 return LHS.first < RHS; 423 } 424 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 425 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 426 return LHS.first < RHS.first; 427 } 428 bool operator()(const llvm::APSInt &LHS, 429 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 430 return LHS < RHS.first; 431 } 432 }; 433} 434 435/// CmpCaseVals - Comparison predicate for sorting case values. 436/// 437static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 438 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 439 if (lhs.first < rhs.first) 440 return true; 441 442 if (lhs.first == rhs.first && 443 lhs.second->getCaseLoc().getRawEncoding() 444 < rhs.second->getCaseLoc().getRawEncoding()) 445 return true; 446 return false; 447} 448 449/// CmpEnumVals - Comparison predicate for sorting enumeration values. 450/// 451static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 452 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 453{ 454 return lhs.first < rhs.first; 455} 456 457/// EqEnumVals - Comparison preficate for uniqing enumeration values. 458/// 459static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 460 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 461{ 462 return lhs.first == rhs.first; 463} 464 465/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 466/// potentially integral-promoted expression @p expr. 467static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 468 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 469 expr = cleanups->getSubExpr(); 470 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 471 if (impcast->getCastKind() != CK_IntegralCast) break; 472 expr = impcast->getSubExpr(); 473 } 474 return expr->getType(); 475} 476 477StmtResult 478Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 479 Decl *CondVar) { 480 ExprResult CondResult; 481 482 VarDecl *ConditionVar = 0; 483 if (CondVar) { 484 ConditionVar = cast<VarDecl>(CondVar); 485 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 486 if (CondResult.isInvalid()) 487 return StmtError(); 488 489 Cond = CondResult.release(); 490 } 491 492 if (!Cond) 493 return StmtError(); 494 495 CondResult = CheckPlaceholderExpr(Cond); 496 if (CondResult.isInvalid()) 497 return StmtError(); 498 499 CondResult 500 = ConvertToIntegralOrEnumerationType(SwitchLoc, CondResult.take(), 501 PDiag(diag::err_typecheck_statement_requires_integer), 502 PDiag(diag::err_switch_incomplete_class_type) 503 << Cond->getSourceRange(), 504 PDiag(diag::err_switch_explicit_conversion), 505 PDiag(diag::note_switch_conversion), 506 PDiag(diag::err_switch_multiple_conversions), 507 PDiag(diag::note_switch_conversion), 508 PDiag(0)); 509 if (CondResult.isInvalid()) return StmtError(); 510 Cond = CondResult.take(); 511 512 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 513 CondResult = UsualUnaryConversions(Cond); 514 if (CondResult.isInvalid()) return StmtError(); 515 Cond = CondResult.take(); 516 517 if (!CondVar) { 518 CheckImplicitConversions(Cond, SwitchLoc); 519 CondResult = MaybeCreateExprWithCleanups(Cond); 520 if (CondResult.isInvalid()) 521 return StmtError(); 522 Cond = CondResult.take(); 523 } 524 525 getCurFunction()->setHasBranchIntoScope(); 526 527 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 528 getCurFunction()->SwitchStack.push_back(SS); 529 return Owned(SS); 530} 531 532static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 533 if (Val.getBitWidth() < BitWidth) 534 Val = Val.extend(BitWidth); 535 else if (Val.getBitWidth() > BitWidth) 536 Val = Val.trunc(BitWidth); 537 Val.setIsSigned(IsSigned); 538} 539 540StmtResult 541Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 542 Stmt *BodyStmt) { 543 SwitchStmt *SS = cast<SwitchStmt>(Switch); 544 assert(SS == getCurFunction()->SwitchStack.back() && 545 "switch stack missing push/pop!"); 546 547 SS->setBody(BodyStmt, SwitchLoc); 548 getCurFunction()->SwitchStack.pop_back(); 549 550 Expr *CondExpr = SS->getCond(); 551 if (!CondExpr) return StmtError(); 552 553 QualType CondType = CondExpr->getType(); 554 555 Expr *CondExprBeforePromotion = CondExpr; 556 QualType CondTypeBeforePromotion = 557 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 558 559 // C++ 6.4.2.p2: 560 // Integral promotions are performed (on the switch condition). 561 // 562 // A case value unrepresentable by the original switch condition 563 // type (before the promotion) doesn't make sense, even when it can 564 // be represented by the promoted type. Therefore we need to find 565 // the pre-promotion type of the switch condition. 566 if (!CondExpr->isTypeDependent()) { 567 // We have already converted the expression to an integral or enumeration 568 // type, when we started the switch statement. If we don't have an 569 // appropriate type now, just return an error. 570 if (!CondType->isIntegralOrEnumerationType()) 571 return StmtError(); 572 573 if (CondExpr->isKnownToHaveBooleanValue()) { 574 // switch(bool_expr) {...} is often a programmer error, e.g. 575 // switch(n && mask) { ... } // Doh - should be "n & mask". 576 // One can always use an if statement instead of switch(bool_expr). 577 Diag(SwitchLoc, diag::warn_bool_switch_condition) 578 << CondExpr->getSourceRange(); 579 } 580 } 581 582 // Get the bitwidth of the switched-on value before promotions. We must 583 // convert the integer case values to this width before comparison. 584 bool HasDependentValue 585 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 586 unsigned CondWidth 587 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 588 bool CondIsSigned 589 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 590 591 // Accumulate all of the case values in a vector so that we can sort them 592 // and detect duplicates. This vector contains the APInt for the case after 593 // it has been converted to the condition type. 594 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 595 CaseValsTy CaseVals; 596 597 // Keep track of any GNU case ranges we see. The APSInt is the low value. 598 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 599 CaseRangesTy CaseRanges; 600 601 DefaultStmt *TheDefaultStmt = 0; 602 603 bool CaseListIsErroneous = false; 604 605 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 606 SC = SC->getNextSwitchCase()) { 607 608 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 609 if (TheDefaultStmt) { 610 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 611 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 612 613 // FIXME: Remove the default statement from the switch block so that 614 // we'll return a valid AST. This requires recursing down the AST and 615 // finding it, not something we are set up to do right now. For now, 616 // just lop the entire switch stmt out of the AST. 617 CaseListIsErroneous = true; 618 } 619 TheDefaultStmt = DS; 620 621 } else { 622 CaseStmt *CS = cast<CaseStmt>(SC); 623 624 // We already verified that the expression has a i-c-e value (C99 625 // 6.8.4.2p3) - get that value now. 626 Expr *Lo = CS->getLHS(); 627 628 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 629 HasDependentValue = true; 630 break; 631 } 632 633 llvm::APSInt LoVal = Lo->EvaluateKnownConstInt(Context); 634 635 // Convert the value to the same width/sign as the condition. 636 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 637 Lo->getLocStart(), 638 diag::warn_case_value_overflow); 639 640 // If the LHS is not the same type as the condition, insert an implicit 641 // cast. 642 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 643 CS->setLHS(Lo); 644 645 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 646 if (CS->getRHS()) { 647 if (CS->getRHS()->isTypeDependent() || 648 CS->getRHS()->isValueDependent()) { 649 HasDependentValue = true; 650 break; 651 } 652 CaseRanges.push_back(std::make_pair(LoVal, CS)); 653 } else 654 CaseVals.push_back(std::make_pair(LoVal, CS)); 655 } 656 } 657 658 if (!HasDependentValue) { 659 // If we don't have a default statement, check whether the 660 // condition is constant. 661 llvm::APSInt ConstantCondValue; 662 bool HasConstantCond = false; 663 bool ShouldCheckConstantCond = false; 664 if (!HasDependentValue && !TheDefaultStmt) { 665 Expr::EvalResult Result; 666 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 667 if (HasConstantCond) { 668 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 669 ConstantCondValue = Result.Val.getInt(); 670 ShouldCheckConstantCond = true; 671 672 assert(ConstantCondValue.getBitWidth() == CondWidth && 673 ConstantCondValue.isSigned() == CondIsSigned); 674 } 675 } 676 677 // Sort all the scalar case values so we can easily detect duplicates. 678 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 679 680 if (!CaseVals.empty()) { 681 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 682 if (ShouldCheckConstantCond && 683 CaseVals[i].first == ConstantCondValue) 684 ShouldCheckConstantCond = false; 685 686 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 687 // If we have a duplicate, report it. 688 Diag(CaseVals[i].second->getLHS()->getLocStart(), 689 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 690 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 691 diag::note_duplicate_case_prev); 692 // FIXME: We really want to remove the bogus case stmt from the 693 // substmt, but we have no way to do this right now. 694 CaseListIsErroneous = true; 695 } 696 } 697 } 698 699 // Detect duplicate case ranges, which usually don't exist at all in 700 // the first place. 701 if (!CaseRanges.empty()) { 702 // Sort all the case ranges by their low value so we can easily detect 703 // overlaps between ranges. 704 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 705 706 // Scan the ranges, computing the high values and removing empty ranges. 707 std::vector<llvm::APSInt> HiVals; 708 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 709 llvm::APSInt &LoVal = CaseRanges[i].first; 710 CaseStmt *CR = CaseRanges[i].second; 711 Expr *Hi = CR->getRHS(); 712 llvm::APSInt HiVal = Hi->EvaluateKnownConstInt(Context); 713 714 // Convert the value to the same width/sign as the condition. 715 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 716 Hi->getLocStart(), 717 diag::warn_case_value_overflow); 718 719 // If the LHS is not the same type as the condition, insert an implicit 720 // cast. 721 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 722 CR->setRHS(Hi); 723 724 // If the low value is bigger than the high value, the case is empty. 725 if (LoVal > HiVal) { 726 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 727 << SourceRange(CR->getLHS()->getLocStart(), 728 Hi->getLocEnd()); 729 CaseRanges.erase(CaseRanges.begin()+i); 730 --i, --e; 731 continue; 732 } 733 734 if (ShouldCheckConstantCond && 735 LoVal <= ConstantCondValue && 736 ConstantCondValue <= HiVal) 737 ShouldCheckConstantCond = false; 738 739 HiVals.push_back(HiVal); 740 } 741 742 // Rescan the ranges, looking for overlap with singleton values and other 743 // ranges. Since the range list is sorted, we only need to compare case 744 // ranges with their neighbors. 745 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 746 llvm::APSInt &CRLo = CaseRanges[i].first; 747 llvm::APSInt &CRHi = HiVals[i]; 748 CaseStmt *CR = CaseRanges[i].second; 749 750 // Check to see whether the case range overlaps with any 751 // singleton cases. 752 CaseStmt *OverlapStmt = 0; 753 llvm::APSInt OverlapVal(32); 754 755 // Find the smallest value >= the lower bound. If I is in the 756 // case range, then we have overlap. 757 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 758 CaseVals.end(), CRLo, 759 CaseCompareFunctor()); 760 if (I != CaseVals.end() && I->first < CRHi) { 761 OverlapVal = I->first; // Found overlap with scalar. 762 OverlapStmt = I->second; 763 } 764 765 // Find the smallest value bigger than the upper bound. 766 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 767 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 768 OverlapVal = (I-1)->first; // Found overlap with scalar. 769 OverlapStmt = (I-1)->second; 770 } 771 772 // Check to see if this case stmt overlaps with the subsequent 773 // case range. 774 if (i && CRLo <= HiVals[i-1]) { 775 OverlapVal = HiVals[i-1]; // Found overlap with range. 776 OverlapStmt = CaseRanges[i-1].second; 777 } 778 779 if (OverlapStmt) { 780 // If we have a duplicate, report it. 781 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 782 << OverlapVal.toString(10); 783 Diag(OverlapStmt->getLHS()->getLocStart(), 784 diag::note_duplicate_case_prev); 785 // FIXME: We really want to remove the bogus case stmt from the 786 // substmt, but we have no way to do this right now. 787 CaseListIsErroneous = true; 788 } 789 } 790 } 791 792 // Complain if we have a constant condition and we didn't find a match. 793 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 794 // TODO: it would be nice if we printed enums as enums, chars as 795 // chars, etc. 796 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 797 << ConstantCondValue.toString(10) 798 << CondExpr->getSourceRange(); 799 } 800 801 // Check to see if switch is over an Enum and handles all of its 802 // values. We only issue a warning if there is not 'default:', but 803 // we still do the analysis to preserve this information in the AST 804 // (which can be used by flow-based analyes). 805 // 806 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 807 808 // If switch has default case, then ignore it. 809 if (!CaseListIsErroneous && !HasConstantCond && ET) { 810 const EnumDecl *ED = ET->getDecl(); 811 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 812 EnumValsTy; 813 EnumValsTy EnumVals; 814 815 // Gather all enum values, set their type and sort them, 816 // allowing easier comparison with CaseVals. 817 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 818 EDI != ED->enumerator_end(); ++EDI) { 819 llvm::APSInt Val = EDI->getInitVal(); 820 AdjustAPSInt(Val, CondWidth, CondIsSigned); 821 EnumVals.push_back(std::make_pair(Val, *EDI)); 822 } 823 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 824 EnumValsTy::iterator EIend = 825 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 826 827 // See which case values aren't in enum. 828 // TODO: we might want to check whether case values are out of the 829 // enum even if we don't want to check whether all cases are handled. 830 if (!TheDefaultStmt) { 831 EnumValsTy::const_iterator EI = EnumVals.begin(); 832 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 833 CI != CaseVals.end(); CI++) { 834 while (EI != EIend && EI->first < CI->first) 835 EI++; 836 if (EI == EIend || EI->first > CI->first) 837 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 838 << ED->getDeclName(); 839 } 840 // See which of case ranges aren't in enum 841 EI = EnumVals.begin(); 842 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 843 RI != CaseRanges.end() && EI != EIend; RI++) { 844 while (EI != EIend && EI->first < RI->first) 845 EI++; 846 847 if (EI == EIend || EI->first != RI->first) { 848 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 849 << ED->getDeclName(); 850 } 851 852 llvm::APSInt Hi = 853 RI->second->getRHS()->EvaluateKnownConstInt(Context); 854 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 855 while (EI != EIend && EI->first < Hi) 856 EI++; 857 if (EI == EIend || EI->first != Hi) 858 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 859 << ED->getDeclName(); 860 } 861 } 862 863 // Check which enum vals aren't in switch 864 CaseValsTy::const_iterator CI = CaseVals.begin(); 865 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 866 bool hasCasesNotInSwitch = false; 867 868 SmallVector<DeclarationName,8> UnhandledNames; 869 870 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 871 // Drop unneeded case values 872 llvm::APSInt CIVal; 873 while (CI != CaseVals.end() && CI->first < EI->first) 874 CI++; 875 876 if (CI != CaseVals.end() && CI->first == EI->first) 877 continue; 878 879 // Drop unneeded case ranges 880 for (; RI != CaseRanges.end(); RI++) { 881 llvm::APSInt Hi = 882 RI->second->getRHS()->EvaluateKnownConstInt(Context); 883 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 884 if (EI->first <= Hi) 885 break; 886 } 887 888 if (RI == CaseRanges.end() || EI->first < RI->first) { 889 hasCasesNotInSwitch = true; 890 if (!TheDefaultStmt) 891 UnhandledNames.push_back(EI->second->getDeclName()); 892 } 893 } 894 895 // Produce a nice diagnostic if multiple values aren't handled. 896 switch (UnhandledNames.size()) { 897 case 0: break; 898 case 1: 899 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 900 << UnhandledNames[0]; 901 break; 902 case 2: 903 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 904 << UnhandledNames[0] << UnhandledNames[1]; 905 break; 906 case 3: 907 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 908 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 909 break; 910 default: 911 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 912 << (unsigned)UnhandledNames.size() 913 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 914 break; 915 } 916 917 if (!hasCasesNotInSwitch) 918 SS->setAllEnumCasesCovered(); 919 } 920 } 921 922 // FIXME: If the case list was broken is some way, we don't have a good system 923 // to patch it up. Instead, just return the whole substmt as broken. 924 if (CaseListIsErroneous) 925 return StmtError(); 926 927 return Owned(SS); 928} 929 930StmtResult 931Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 932 Decl *CondVar, Stmt *Body) { 933 ExprResult CondResult(Cond.release()); 934 935 VarDecl *ConditionVar = 0; 936 if (CondVar) { 937 ConditionVar = cast<VarDecl>(CondVar); 938 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 939 if (CondResult.isInvalid()) 940 return StmtError(); 941 } 942 Expr *ConditionExpr = CondResult.take(); 943 if (!ConditionExpr) 944 return StmtError(); 945 946 DiagnoseUnusedExprResult(Body); 947 948 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 949 Body, WhileLoc)); 950} 951 952StmtResult 953Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 954 SourceLocation WhileLoc, SourceLocation CondLParen, 955 Expr *Cond, SourceLocation CondRParen) { 956 assert(Cond && "ActOnDoStmt(): missing expression"); 957 958 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 959 if (CondResult.isInvalid() || CondResult.isInvalid()) 960 return StmtError(); 961 Cond = CondResult.take(); 962 963 CheckImplicitConversions(Cond, DoLoc); 964 CondResult = MaybeCreateExprWithCleanups(Cond); 965 if (CondResult.isInvalid()) 966 return StmtError(); 967 Cond = CondResult.take(); 968 969 DiagnoseUnusedExprResult(Body); 970 971 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 972} 973 974StmtResult 975Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 976 Stmt *First, FullExprArg second, Decl *secondVar, 977 FullExprArg third, 978 SourceLocation RParenLoc, Stmt *Body) { 979 if (!getLangOptions().CPlusPlus) { 980 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 981 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 982 // declare identifiers for objects having storage class 'auto' or 983 // 'register'. 984 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 985 DI!=DE; ++DI) { 986 VarDecl *VD = dyn_cast<VarDecl>(*DI); 987 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 988 VD = 0; 989 if (VD == 0) 990 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 991 // FIXME: mark decl erroneous! 992 } 993 } 994 } 995 996 ExprResult SecondResult(second.release()); 997 VarDecl *ConditionVar = 0; 998 if (secondVar) { 999 ConditionVar = cast<VarDecl>(secondVar); 1000 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1001 if (SecondResult.isInvalid()) 1002 return StmtError(); 1003 } 1004 1005 Expr *Third = third.release().takeAs<Expr>(); 1006 1007 DiagnoseUnusedExprResult(First); 1008 DiagnoseUnusedExprResult(Third); 1009 DiagnoseUnusedExprResult(Body); 1010 1011 return Owned(new (Context) ForStmt(Context, First, 1012 SecondResult.take(), ConditionVar, 1013 Third, Body, ForLoc, LParenLoc, 1014 RParenLoc)); 1015} 1016 1017/// In an Objective C collection iteration statement: 1018/// for (x in y) 1019/// x can be an arbitrary l-value expression. Bind it up as a 1020/// full-expression. 1021StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1022 CheckImplicitConversions(E); 1023 ExprResult Result = MaybeCreateExprWithCleanups(E); 1024 if (Result.isInvalid()) return StmtError(); 1025 return Owned(static_cast<Stmt*>(Result.get())); 1026} 1027 1028ExprResult 1029Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1030 assert(collection); 1031 1032 // Bail out early if we've got a type-dependent expression. 1033 if (collection->isTypeDependent()) return Owned(collection); 1034 1035 // Perform normal l-value conversion. 1036 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1037 if (result.isInvalid()) 1038 return ExprError(); 1039 collection = result.take(); 1040 1041 // The operand needs to have object-pointer type. 1042 // TODO: should we do a contextual conversion? 1043 const ObjCObjectPointerType *pointerType = 1044 collection->getType()->getAs<ObjCObjectPointerType>(); 1045 if (!pointerType) 1046 return Diag(forLoc, diag::err_collection_expr_type) 1047 << collection->getType() << collection->getSourceRange(); 1048 1049 // Check that the operand provides 1050 // - countByEnumeratingWithState:objects:count: 1051 const ObjCObjectType *objectType = pointerType->getObjectType(); 1052 ObjCInterfaceDecl *iface = objectType->getInterface(); 1053 1054 // If we have a forward-declared type, we can't do this check. 1055 if (iface && iface->isForwardDecl()) { 1056 // This is ill-formed under ARC. 1057 if (getLangOptions().ObjCAutoRefCount) { 1058 Diag(forLoc, diag::err_arc_collection_forward) 1059 << pointerType->getPointeeType() << collection->getSourceRange(); 1060 } 1061 1062 // Otherwise, if we have any useful type information, check that 1063 // the type declares the appropriate method. 1064 } else if (iface || !objectType->qual_empty()) { 1065 IdentifierInfo *selectorIdents[] = { 1066 &Context.Idents.get("countByEnumeratingWithState"), 1067 &Context.Idents.get("objects"), 1068 &Context.Idents.get("count") 1069 }; 1070 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1071 1072 ObjCMethodDecl *method = 0; 1073 1074 // If there's an interface, look in both the public and private APIs. 1075 if (iface) { 1076 method = iface->lookupInstanceMethod(selector); 1077 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1078 } 1079 1080 // Also check protocol qualifiers. 1081 if (!method) 1082 method = LookupMethodInQualifiedType(selector, pointerType, 1083 /*instance*/ true); 1084 1085 // If we didn't find it anywhere, give up. 1086 if (!method) { 1087 Diag(forLoc, diag::warn_collection_expr_type) 1088 << collection->getType() << selector << collection->getSourceRange(); 1089 } 1090 1091 // TODO: check for an incompatible signature? 1092 } 1093 1094 // Wrap up any cleanups in the expression. 1095 return Owned(MaybeCreateExprWithCleanups(collection)); 1096} 1097 1098StmtResult 1099Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1100 SourceLocation LParenLoc, 1101 Stmt *First, Expr *Second, 1102 SourceLocation RParenLoc, Stmt *Body) { 1103 if (First) { 1104 QualType FirstType; 1105 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1106 if (!DS->isSingleDecl()) 1107 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1108 diag::err_toomany_element_decls)); 1109 1110 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1111 FirstType = D->getType(); 1112 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1113 // declare identifiers for objects having storage class 'auto' or 1114 // 'register'. 1115 if (!D->hasLocalStorage()) 1116 return StmtError(Diag(D->getLocation(), 1117 diag::err_non_variable_decl_in_for)); 1118 } else { 1119 Expr *FirstE = cast<Expr>(First); 1120 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1121 return StmtError(Diag(First->getLocStart(), 1122 diag::err_selector_element_not_lvalue) 1123 << First->getSourceRange()); 1124 1125 FirstType = static_cast<Expr*>(First)->getType(); 1126 } 1127 if (!FirstType->isDependentType() && 1128 !FirstType->isObjCObjectPointerType() && 1129 !FirstType->isBlockPointerType()) 1130 Diag(ForLoc, diag::err_selector_element_type) 1131 << FirstType << First->getSourceRange(); 1132 } 1133 1134 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1135 ForLoc, RParenLoc)); 1136} 1137 1138namespace { 1139 1140enum BeginEndFunction { 1141 BEF_begin, 1142 BEF_end 1143}; 1144 1145/// Build a variable declaration for a for-range statement. 1146static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1147 QualType Type, const char *Name) { 1148 DeclContext *DC = SemaRef.CurContext; 1149 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1150 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1151 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1152 TInfo, SC_Auto, SC_None); 1153 Decl->setImplicit(); 1154 return Decl; 1155} 1156 1157/// Finish building a variable declaration for a for-range statement. 1158/// \return true if an error occurs. 1159static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1160 SourceLocation Loc, int diag) { 1161 // Deduce the type for the iterator variable now rather than leaving it to 1162 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1163 TypeSourceInfo *InitTSI = 0; 1164 if (Init->getType()->isVoidType() || 1165 !SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI)) 1166 SemaRef.Diag(Loc, diag) << Init->getType(); 1167 if (!InitTSI) { 1168 Decl->setInvalidDecl(); 1169 return true; 1170 } 1171 Decl->setTypeSourceInfo(InitTSI); 1172 Decl->setType(InitTSI->getType()); 1173 1174 // In ARC, infer lifetime. 1175 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1176 // we're doing the equivalent of fast iteration. 1177 if (SemaRef.getLangOptions().ObjCAutoRefCount && 1178 SemaRef.inferObjCARCLifetime(Decl)) 1179 Decl->setInvalidDecl(); 1180 1181 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1182 /*TypeMayContainAuto=*/false); 1183 SemaRef.FinalizeDeclaration(Decl); 1184 SemaRef.CurContext->addHiddenDecl(Decl); 1185 return false; 1186} 1187 1188/// Produce a note indicating which begin/end function was implicitly called 1189/// by a C++0x for-range statement. This is often not obvious from the code, 1190/// nor from the diagnostics produced when analysing the implicit expressions 1191/// required in a for-range statement. 1192void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1193 BeginEndFunction BEF) { 1194 CallExpr *CE = dyn_cast<CallExpr>(E); 1195 if (!CE) 1196 return; 1197 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1198 if (!D) 1199 return; 1200 SourceLocation Loc = D->getLocation(); 1201 1202 std::string Description; 1203 bool IsTemplate = false; 1204 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1205 Description = SemaRef.getTemplateArgumentBindingsText( 1206 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1207 IsTemplate = true; 1208 } 1209 1210 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1211 << BEF << IsTemplate << Description << E->getType(); 1212} 1213 1214/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1215/// given LookupResult is non-empty, it is assumed to describe a member which 1216/// will be invoked. Otherwise, the function will be found via argument 1217/// dependent lookup. 1218static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1219 SourceLocation Loc, 1220 VarDecl *Decl, 1221 BeginEndFunction BEF, 1222 const DeclarationNameInfo &NameInfo, 1223 LookupResult &MemberLookup, 1224 Expr *Range) { 1225 ExprResult CallExpr; 1226 if (!MemberLookup.empty()) { 1227 ExprResult MemberRef = 1228 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1229 /*IsPtr=*/false, CXXScopeSpec(), 1230 /*Qualifier=*/0, MemberLookup, 1231 /*TemplateArgs=*/0); 1232 if (MemberRef.isInvalid()) 1233 return ExprError(); 1234 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1235 Loc, 0); 1236 if (CallExpr.isInvalid()) 1237 return ExprError(); 1238 } else { 1239 UnresolvedSet<0> FoundNames; 1240 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1241 // std is an associated namespace. 1242 UnresolvedLookupExpr *Fn = 1243 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1244 NestedNameSpecifierLoc(), NameInfo, 1245 /*NeedsADL=*/true, /*Overloaded=*/false, 1246 FoundNames.begin(), FoundNames.end(), 1247 /*LookInStdNamespace=*/true); 1248 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1249 0); 1250 if (CallExpr.isInvalid()) { 1251 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1252 << Range->getType(); 1253 return ExprError(); 1254 } 1255 } 1256 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1257 diag::err_for_range_iter_deduction_failure)) { 1258 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1259 return ExprError(); 1260 } 1261 return CallExpr; 1262} 1263 1264} 1265 1266/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1267/// 1268/// C++0x [stmt.ranged]: 1269/// A range-based for statement is equivalent to 1270/// 1271/// { 1272/// auto && __range = range-init; 1273/// for ( auto __begin = begin-expr, 1274/// __end = end-expr; 1275/// __begin != __end; 1276/// ++__begin ) { 1277/// for-range-declaration = *__begin; 1278/// statement 1279/// } 1280/// } 1281/// 1282/// The body of the loop is not available yet, since it cannot be analysed until 1283/// we have determined the type of the for-range-declaration. 1284StmtResult 1285Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1286 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1287 SourceLocation RParenLoc) { 1288 if (!First || !Range) 1289 return StmtError(); 1290 1291 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1292 assert(DS && "first part of for range not a decl stmt"); 1293 1294 if (!DS->isSingleDecl()) { 1295 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1296 return StmtError(); 1297 } 1298 if (DS->getSingleDecl()->isInvalidDecl()) 1299 return StmtError(); 1300 1301 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1302 return StmtError(); 1303 1304 // Build auto && __range = range-init 1305 SourceLocation RangeLoc = Range->getLocStart(); 1306 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1307 Context.getAutoRRefDeductType(), 1308 "__range"); 1309 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1310 diag::err_for_range_deduction_failure)) 1311 return StmtError(); 1312 1313 // Claim the type doesn't contain auto: we've already done the checking. 1314 DeclGroupPtrTy RangeGroup = 1315 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1316 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1317 if (RangeDecl.isInvalid()) 1318 return StmtError(); 1319 1320 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1321 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1322 RParenLoc); 1323} 1324 1325/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1326StmtResult 1327Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1328 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1329 Expr *Inc, Stmt *LoopVarDecl, 1330 SourceLocation RParenLoc) { 1331 Scope *S = getCurScope(); 1332 1333 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1334 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1335 QualType RangeVarType = RangeVar->getType(); 1336 1337 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1338 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1339 1340 StmtResult BeginEndDecl = BeginEnd; 1341 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1342 1343 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1344 SourceLocation RangeLoc = RangeVar->getLocation(); 1345 1346 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1347 1348 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1349 VK_LValue, ColonLoc); 1350 if (BeginRangeRef.isInvalid()) 1351 return StmtError(); 1352 1353 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1354 VK_LValue, ColonLoc); 1355 if (EndRangeRef.isInvalid()) 1356 return StmtError(); 1357 1358 QualType AutoType = Context.getAutoDeductType(); 1359 Expr *Range = RangeVar->getInit(); 1360 if (!Range) 1361 return StmtError(); 1362 QualType RangeType = Range->getType(); 1363 1364 if (RequireCompleteType(RangeLoc, RangeType, 1365 PDiag(diag::err_for_range_incomplete_type))) 1366 return StmtError(); 1367 1368 // Build auto __begin = begin-expr, __end = end-expr. 1369 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1370 "__begin"); 1371 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1372 "__end"); 1373 1374 // Build begin-expr and end-expr and attach to __begin and __end variables. 1375 ExprResult BeginExpr, EndExpr; 1376 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1377 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1378 // __range + __bound, respectively, where __bound is the array bound. If 1379 // _RangeT is an array of unknown size or an array of incomplete type, 1380 // the program is ill-formed; 1381 1382 // begin-expr is __range. 1383 BeginExpr = BeginRangeRef; 1384 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1385 diag::err_for_range_iter_deduction_failure)) { 1386 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1387 return StmtError(); 1388 } 1389 1390 // Find the array bound. 1391 ExprResult BoundExpr; 1392 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1393 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1394 Context.getPointerDiffType(), 1395 RangeLoc)); 1396 else if (const VariableArrayType *VAT = 1397 dyn_cast<VariableArrayType>(UnqAT)) 1398 BoundExpr = VAT->getSizeExpr(); 1399 else { 1400 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1401 // UnqAT is not incomplete and Range is not type-dependent. 1402 llvm_unreachable("Unexpected array type in for-range"); 1403 } 1404 1405 // end-expr is __range + __bound. 1406 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1407 BoundExpr.get()); 1408 if (EndExpr.isInvalid()) 1409 return StmtError(); 1410 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1411 diag::err_for_range_iter_deduction_failure)) { 1412 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1413 return StmtError(); 1414 } 1415 } else { 1416 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1417 ColonLoc); 1418 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1419 ColonLoc); 1420 1421 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1422 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1423 1424 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1425 // - if _RangeT is a class type, the unqualified-ids begin and end are 1426 // looked up in the scope of class _RangeT as if by class member access 1427 // lookup (3.4.5), and if either (or both) finds at least one 1428 // declaration, begin-expr and end-expr are __range.begin() and 1429 // __range.end(), respectively; 1430 LookupQualifiedName(BeginMemberLookup, D); 1431 LookupQualifiedName(EndMemberLookup, D); 1432 1433 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1434 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1435 << RangeType << BeginMemberLookup.empty(); 1436 return StmtError(); 1437 } 1438 } else { 1439 // - otherwise, begin-expr and end-expr are begin(__range) and 1440 // end(__range), respectively, where begin and end are looked up with 1441 // argument-dependent lookup (3.4.2). For the purposes of this name 1442 // lookup, namespace std is an associated namespace. 1443 } 1444 1445 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1446 BEF_begin, BeginNameInfo, 1447 BeginMemberLookup, 1448 BeginRangeRef.get()); 1449 if (BeginExpr.isInvalid()) 1450 return StmtError(); 1451 1452 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1453 BEF_end, EndNameInfo, 1454 EndMemberLookup, EndRangeRef.get()); 1455 if (EndExpr.isInvalid()) 1456 return StmtError(); 1457 } 1458 1459 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1460 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1461 if (!Context.hasSameType(BeginType, EndType)) { 1462 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1463 << BeginType << EndType; 1464 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1465 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1466 } 1467 1468 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1469 // Claim the type doesn't contain auto: we've already done the checking. 1470 DeclGroupPtrTy BeginEndGroup = 1471 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1472 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1473 1474 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1475 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1476 VK_LValue, ColonLoc); 1477 if (BeginRef.isInvalid()) 1478 return StmtError(); 1479 1480 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1481 VK_LValue, ColonLoc); 1482 if (EndRef.isInvalid()) 1483 return StmtError(); 1484 1485 // Build and check __begin != __end expression. 1486 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1487 BeginRef.get(), EndRef.get()); 1488 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1489 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1490 if (NotEqExpr.isInvalid()) { 1491 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1492 if (!Context.hasSameType(BeginType, EndType)) 1493 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1494 return StmtError(); 1495 } 1496 1497 // Build and check ++__begin expression. 1498 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1499 VK_LValue, ColonLoc); 1500 if (BeginRef.isInvalid()) 1501 return StmtError(); 1502 1503 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1504 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1505 if (IncrExpr.isInvalid()) { 1506 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1507 return StmtError(); 1508 } 1509 1510 // Build and check *__begin expression. 1511 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1512 VK_LValue, ColonLoc); 1513 if (BeginRef.isInvalid()) 1514 return StmtError(); 1515 1516 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1517 if (DerefExpr.isInvalid()) { 1518 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1519 return StmtError(); 1520 } 1521 1522 // Attach *__begin as initializer for VD. 1523 if (!LoopVar->isInvalidDecl()) { 1524 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1525 /*TypeMayContainAuto=*/true); 1526 if (LoopVar->isInvalidDecl()) 1527 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1528 } 1529 } else { 1530 // The range is implicitly used as a placeholder when it is dependent. 1531 RangeVar->setUsed(); 1532 } 1533 1534 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1535 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1536 NotEqExpr.take(), IncrExpr.take(), 1537 LoopVarDS, /*Body=*/0, ForLoc, 1538 ColonLoc, RParenLoc)); 1539} 1540 1541/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1542/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1543/// body cannot be performed until after the type of the range variable is 1544/// determined. 1545StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1546 if (!S || !B) 1547 return StmtError(); 1548 1549 cast<CXXForRangeStmt>(S)->setBody(B); 1550 return S; 1551} 1552 1553StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1554 SourceLocation LabelLoc, 1555 LabelDecl *TheDecl) { 1556 getCurFunction()->setHasBranchIntoScope(); 1557 TheDecl->setUsed(); 1558 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1559} 1560 1561StmtResult 1562Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1563 Expr *E) { 1564 // Convert operand to void* 1565 if (!E->isTypeDependent()) { 1566 QualType ETy = E->getType(); 1567 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1568 ExprResult ExprRes = Owned(E); 1569 AssignConvertType ConvTy = 1570 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1571 if (ExprRes.isInvalid()) 1572 return StmtError(); 1573 E = ExprRes.take(); 1574 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1575 return StmtError(); 1576 } 1577 1578 getCurFunction()->setHasIndirectGoto(); 1579 1580 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1581} 1582 1583StmtResult 1584Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1585 Scope *S = CurScope->getContinueParent(); 1586 if (!S) { 1587 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1588 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1589 } 1590 1591 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1592} 1593 1594StmtResult 1595Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1596 Scope *S = CurScope->getBreakParent(); 1597 if (!S) { 1598 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1599 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1600 } 1601 1602 return Owned(new (Context) BreakStmt(BreakLoc)); 1603} 1604 1605/// \brief Determine whether the given expression is a candidate for 1606/// copy elision in either a return statement or a throw expression. 1607/// 1608/// \param ReturnType If we're determining the copy elision candidate for 1609/// a return statement, this is the return type of the function. If we're 1610/// determining the copy elision candidate for a throw expression, this will 1611/// be a NULL type. 1612/// 1613/// \param E The expression being returned from the function or block, or 1614/// being thrown. 1615/// 1616/// \param AllowFunctionParameter Whether we allow function parameters to 1617/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1618/// we re-use this logic to determine whether we should try to move as part of 1619/// a return or throw (which does allow function parameters). 1620/// 1621/// \returns The NRVO candidate variable, if the return statement may use the 1622/// NRVO, or NULL if there is no such candidate. 1623const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1624 Expr *E, 1625 bool AllowFunctionParameter) { 1626 QualType ExprType = E->getType(); 1627 // - in a return statement in a function with ... 1628 // ... a class return type ... 1629 if (!ReturnType.isNull()) { 1630 if (!ReturnType->isRecordType()) 1631 return 0; 1632 // ... the same cv-unqualified type as the function return type ... 1633 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1634 return 0; 1635 } 1636 1637 // ... the expression is the name of a non-volatile automatic object 1638 // (other than a function or catch-clause parameter)) ... 1639 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1640 if (!DR) 1641 return 0; 1642 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1643 if (!VD) 1644 return 0; 1645 1646 if (VD->hasLocalStorage() && !VD->isExceptionVariable() && 1647 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1648 !VD->getType().isVolatileQualified() && 1649 ((VD->getKind() == Decl::Var) || 1650 (AllowFunctionParameter && VD->getKind() == Decl::ParmVar))) 1651 return VD; 1652 1653 return 0; 1654} 1655 1656/// \brief Perform the initialization of a potentially-movable value, which 1657/// is the result of return value. 1658/// 1659/// This routine implements C++0x [class.copy]p33, which attempts to treat 1660/// returned lvalues as rvalues in certain cases (to prefer move construction), 1661/// then falls back to treating them as lvalues if that failed. 1662ExprResult 1663Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1664 const VarDecl *NRVOCandidate, 1665 QualType ResultType, 1666 Expr *Value, 1667 bool AllowNRVO) { 1668 // C++0x [class.copy]p33: 1669 // When the criteria for elision of a copy operation are met or would 1670 // be met save for the fact that the source object is a function 1671 // parameter, and the object to be copied is designated by an lvalue, 1672 // overload resolution to select the constructor for the copy is first 1673 // performed as if the object were designated by an rvalue. 1674 ExprResult Res = ExprError(); 1675 if (AllowNRVO && 1676 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 1677 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1678 Value->getType(), CK_LValueToRValue, 1679 Value, VK_XValue); 1680 1681 Expr *InitExpr = &AsRvalue; 1682 InitializationKind Kind 1683 = InitializationKind::CreateCopy(Value->getLocStart(), 1684 Value->getLocStart()); 1685 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1686 1687 // [...] If overload resolution fails, or if the type of the first 1688 // parameter of the selected constructor is not an rvalue reference 1689 // to the object's type (possibly cv-qualified), overload resolution 1690 // is performed again, considering the object as an lvalue. 1691 if (Seq) { 1692 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1693 StepEnd = Seq.step_end(); 1694 Step != StepEnd; ++Step) { 1695 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 1696 continue; 1697 1698 CXXConstructorDecl *Constructor 1699 = cast<CXXConstructorDecl>(Step->Function.Function); 1700 1701 const RValueReferenceType *RRefType 1702 = Constructor->getParamDecl(0)->getType() 1703 ->getAs<RValueReferenceType>(); 1704 1705 // If we don't meet the criteria, break out now. 1706 if (!RRefType || 1707 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1708 Context.getTypeDeclType(Constructor->getParent()))) 1709 break; 1710 1711 // Promote "AsRvalue" to the heap, since we now need this 1712 // expression node to persist. 1713 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1714 CK_LValueToRValue, Value, 0, 1715 VK_XValue); 1716 1717 // Complete type-checking the initialization of the return type 1718 // using the constructor we found. 1719 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1720 } 1721 } 1722 } 1723 1724 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1725 // above, or overload resolution failed. Either way, we need to try 1726 // (again) now with the return value expression as written. 1727 if (Res.isInvalid()) 1728 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1729 1730 return Res; 1731} 1732 1733/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1734/// 1735StmtResult 1736Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1737 // If this is the first return we've seen in the block, infer the type of 1738 // the block from it. 1739 BlockScopeInfo *CurBlock = getCurBlock(); 1740 if (CurBlock->ReturnType.isNull()) { 1741 if (RetValExp) { 1742 // Don't call UsualUnaryConversions(), since we don't want to do 1743 // integer promotions here. 1744 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 1745 if (Result.isInvalid()) 1746 return StmtError(); 1747 RetValExp = Result.take(); 1748 1749 if (!RetValExp->isTypeDependent()) { 1750 CurBlock->ReturnType = RetValExp->getType(); 1751 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1752 // We have to remove a 'const' added to copied-in variable which was 1753 // part of the implementation spec. and not the actual qualifier for 1754 // the variable. 1755 if (CDRE->isConstQualAdded()) 1756 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1757 } 1758 } else 1759 CurBlock->ReturnType = Context.DependentTy; 1760 } else 1761 CurBlock->ReturnType = Context.VoidTy; 1762 } 1763 QualType FnRetType = CurBlock->ReturnType; 1764 1765 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1766 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1767 << getCurFunctionOrMethodDecl()->getDeclName(); 1768 return StmtError(); 1769 } 1770 1771 // Otherwise, verify that this result type matches the previous one. We are 1772 // pickier with blocks than for normal functions because we don't have GCC 1773 // compatibility to worry about here. 1774 const VarDecl *NRVOCandidate = 0; 1775 if (FnRetType->isDependentType()) { 1776 // Delay processing for now. TODO: there are lots of dependent 1777 // types we can conclusively prove aren't void. 1778 } else if (FnRetType->isVoidType()) { 1779 if (RetValExp && 1780 !(getLangOptions().CPlusPlus && 1781 (RetValExp->isTypeDependent() || 1782 RetValExp->getType()->isVoidType()))) { 1783 Diag(ReturnLoc, diag::err_return_block_has_expr); 1784 RetValExp = 0; 1785 } 1786 } else if (!RetValExp) { 1787 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1788 } else if (!RetValExp->isTypeDependent()) { 1789 // we have a non-void block with an expression, continue checking 1790 1791 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1792 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1793 // function return. 1794 1795 // In C++ the return statement is handled via a copy initialization. 1796 // the C version of which boils down to CheckSingleAssignmentConstraints. 1797 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1798 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1799 FnRetType, 1800 NRVOCandidate != 0); 1801 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1802 FnRetType, RetValExp); 1803 if (Res.isInvalid()) { 1804 // FIXME: Cleanup temporaries here, anyway? 1805 return StmtError(); 1806 } 1807 RetValExp = Res.take(); 1808 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1809 } 1810 1811 if (RetValExp) { 1812 CheckImplicitConversions(RetValExp, ReturnLoc); 1813 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1814 } 1815 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 1816 NRVOCandidate); 1817 1818 // If we need to check for the named return value optimization, save the 1819 // return statement in our scope for later processing. 1820 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1821 !CurContext->isDependentContext()) 1822 FunctionScopes.back()->Returns.push_back(Result); 1823 1824 return Owned(Result); 1825} 1826 1827StmtResult 1828Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1829 // Check for unexpanded parameter packs. 1830 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 1831 return StmtError(); 1832 1833 if (getCurBlock()) 1834 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1835 1836 QualType FnRetType; 1837 QualType DeclaredRetType; 1838 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1839 FnRetType = FD->getResultType(); 1840 DeclaredRetType = FnRetType; 1841 if (FD->hasAttr<NoReturnAttr>() || 1842 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1843 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1844 << getCurFunctionOrMethodDecl()->getDeclName(); 1845 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 1846 DeclaredRetType = MD->getResultType(); 1847 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 1848 // In the implementation of a method with a related return type, the 1849 // type used to type-check the validity of return statements within the 1850 // method body is a pointer to the type of the class being implemented. 1851 FnRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 1852 FnRetType = Context.getObjCObjectPointerType(FnRetType); 1853 } else { 1854 FnRetType = DeclaredRetType; 1855 } 1856 } else // If we don't have a function/method context, bail. 1857 return StmtError(); 1858 1859 ReturnStmt *Result = 0; 1860 if (FnRetType->isVoidType()) { 1861 if (RetValExp) { 1862 if (!RetValExp->isTypeDependent()) { 1863 // C99 6.8.6.4p1 (ext_ since GCC warns) 1864 unsigned D = diag::ext_return_has_expr; 1865 if (RetValExp->getType()->isVoidType()) 1866 D = diag::ext_return_has_void_expr; 1867 else { 1868 ExprResult Result = Owned(RetValExp); 1869 Result = IgnoredValueConversions(Result.take()); 1870 if (Result.isInvalid()) 1871 return StmtError(); 1872 RetValExp = Result.take(); 1873 RetValExp = ImpCastExprToType(RetValExp, 1874 Context.VoidTy, CK_ToVoid).take(); 1875 } 1876 1877 // return (some void expression); is legal in C++. 1878 if (D != diag::ext_return_has_void_expr || 1879 !getLangOptions().CPlusPlus) { 1880 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1881 1882 int FunctionKind = 0; 1883 if (isa<ObjCMethodDecl>(CurDecl)) 1884 FunctionKind = 1; 1885 else if (isa<CXXConstructorDecl>(CurDecl)) 1886 FunctionKind = 2; 1887 else if (isa<CXXDestructorDecl>(CurDecl)) 1888 FunctionKind = 3; 1889 1890 Diag(ReturnLoc, D) 1891 << CurDecl->getDeclName() << FunctionKind 1892 << RetValExp->getSourceRange(); 1893 } 1894 } 1895 1896 CheckImplicitConversions(RetValExp, ReturnLoc); 1897 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1898 } 1899 1900 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1901 } else if (!RetValExp && !FnRetType->isDependentType()) { 1902 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1903 // C99 6.8.6.4p1 (ext_ since GCC warns) 1904 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1905 1906 if (FunctionDecl *FD = getCurFunctionDecl()) 1907 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1908 else 1909 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1910 Result = new (Context) ReturnStmt(ReturnLoc); 1911 } else { 1912 const VarDecl *NRVOCandidate = 0; 1913 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1914 // we have a non-void function with an expression, continue checking 1915 1916 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1917 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1918 // function return. 1919 1920 // In C++ the return statement is handled via a copy initialization, 1921 // the C version of which boils down to CheckSingleAssignmentConstraints. 1922 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1923 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1924 FnRetType, 1925 NRVOCandidate != 0); 1926 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1927 FnRetType, RetValExp); 1928 if (Res.isInvalid()) { 1929 // FIXME: Cleanup temporaries here, anyway? 1930 return StmtError(); 1931 } 1932 1933 RetValExp = Res.takeAs<Expr>(); 1934 if (RetValExp) 1935 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1936 } 1937 1938 if (RetValExp) { 1939 // If we type-checked an Objective-C method's return type based 1940 // on a related return type, we may need to adjust the return 1941 // type again. Do so now. 1942 if (DeclaredRetType != FnRetType) { 1943 ExprResult result = PerformImplicitConversion(RetValExp, 1944 DeclaredRetType, 1945 AA_Returning); 1946 if (result.isInvalid()) return StmtError(); 1947 RetValExp = result.take(); 1948 } 1949 1950 CheckImplicitConversions(RetValExp, ReturnLoc); 1951 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1952 } 1953 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1954 } 1955 1956 // If we need to check for the named return value optimization, save the 1957 // return statement in our scope for later processing. 1958 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1959 !CurContext->isDependentContext()) 1960 FunctionScopes.back()->Returns.push_back(Result); 1961 1962 return Owned(Result); 1963} 1964 1965/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1966/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1967/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1968/// provide a strong guidance to not use it. 1969/// 1970/// This method checks to see if the argument is an acceptable l-value and 1971/// returns false if it is a case we can handle. 1972static bool CheckAsmLValue(const Expr *E, Sema &S) { 1973 // Type dependent expressions will be checked during instantiation. 1974 if (E->isTypeDependent()) 1975 return false; 1976 1977 if (E->isLValue()) 1978 return false; // Cool, this is an lvalue. 1979 1980 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1981 // are supposed to allow. 1982 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1983 if (E != E2 && E2->isLValue()) { 1984 if (!S.getLangOptions().HeinousExtensions) 1985 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1986 << E->getSourceRange(); 1987 else 1988 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1989 << E->getSourceRange(); 1990 // Accept, even if we emitted an error diagnostic. 1991 return false; 1992 } 1993 1994 // None of the above, just randomly invalid non-lvalue. 1995 return true; 1996} 1997 1998/// isOperandMentioned - Return true if the specified operand # is mentioned 1999/// anywhere in the decomposed asm string. 2000static bool isOperandMentioned(unsigned OpNo, 2001 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2002 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2003 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2004 if (!Piece.isOperand()) continue; 2005 2006 // If this is a reference to the input and if the input was the smaller 2007 // one, then we have to reject this asm. 2008 if (Piece.getOperandNo() == OpNo) 2009 return true; 2010 } 2011 2012 return false; 2013} 2014 2015StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2016 bool IsVolatile, unsigned NumOutputs, 2017 unsigned NumInputs, IdentifierInfo **Names, 2018 MultiExprArg constraints, MultiExprArg exprs, 2019 Expr *asmString, MultiExprArg clobbers, 2020 SourceLocation RParenLoc, bool MSAsm) { 2021 unsigned NumClobbers = clobbers.size(); 2022 StringLiteral **Constraints = 2023 reinterpret_cast<StringLiteral**>(constraints.get()); 2024 Expr **Exprs = exprs.get(); 2025 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2026 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2027 2028 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2029 2030 // The parser verifies that there is a string literal here. 2031 if (!AsmString->isAscii()) 2032 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2033 << AsmString->getSourceRange()); 2034 2035 for (unsigned i = 0; i != NumOutputs; i++) { 2036 StringLiteral *Literal = Constraints[i]; 2037 if (!Literal->isAscii()) 2038 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2039 << Literal->getSourceRange()); 2040 2041 StringRef OutputName; 2042 if (Names[i]) 2043 OutputName = Names[i]->getName(); 2044 2045 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2046 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2047 return StmtError(Diag(Literal->getLocStart(), 2048 diag::err_asm_invalid_output_constraint) 2049 << Info.getConstraintStr()); 2050 2051 // Check that the output exprs are valid lvalues. 2052 Expr *OutputExpr = Exprs[i]; 2053 if (CheckAsmLValue(OutputExpr, *this)) { 2054 return StmtError(Diag(OutputExpr->getLocStart(), 2055 diag::err_asm_invalid_lvalue_in_output) 2056 << OutputExpr->getSourceRange()); 2057 } 2058 2059 OutputConstraintInfos.push_back(Info); 2060 } 2061 2062 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2063 2064 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2065 StringLiteral *Literal = Constraints[i]; 2066 if (!Literal->isAscii()) 2067 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2068 << Literal->getSourceRange()); 2069 2070 StringRef InputName; 2071 if (Names[i]) 2072 InputName = Names[i]->getName(); 2073 2074 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2075 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2076 NumOutputs, Info)) { 2077 return StmtError(Diag(Literal->getLocStart(), 2078 diag::err_asm_invalid_input_constraint) 2079 << Info.getConstraintStr()); 2080 } 2081 2082 Expr *InputExpr = Exprs[i]; 2083 2084 // Only allow void types for memory constraints. 2085 if (Info.allowsMemory() && !Info.allowsRegister()) { 2086 if (CheckAsmLValue(InputExpr, *this)) 2087 return StmtError(Diag(InputExpr->getLocStart(), 2088 diag::err_asm_invalid_lvalue_in_input) 2089 << Info.getConstraintStr() 2090 << InputExpr->getSourceRange()); 2091 } 2092 2093 if (Info.allowsRegister()) { 2094 if (InputExpr->getType()->isVoidType()) { 2095 return StmtError(Diag(InputExpr->getLocStart(), 2096 diag::err_asm_invalid_type_in_input) 2097 << InputExpr->getType() << Info.getConstraintStr() 2098 << InputExpr->getSourceRange()); 2099 } 2100 } 2101 2102 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2103 if (Result.isInvalid()) 2104 return StmtError(); 2105 2106 Exprs[i] = Result.take(); 2107 InputConstraintInfos.push_back(Info); 2108 } 2109 2110 // Check that the clobbers are valid. 2111 for (unsigned i = 0; i != NumClobbers; i++) { 2112 StringLiteral *Literal = Clobbers[i]; 2113 if (!Literal->isAscii()) 2114 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2115 << Literal->getSourceRange()); 2116 2117 StringRef Clobber = Literal->getString(); 2118 2119 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2120 return StmtError(Diag(Literal->getLocStart(), 2121 diag::err_asm_unknown_register_name) << Clobber); 2122 } 2123 2124 AsmStmt *NS = 2125 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2126 NumOutputs, NumInputs, Names, Constraints, Exprs, 2127 AsmString, NumClobbers, Clobbers, RParenLoc); 2128 // Validate the asm string, ensuring it makes sense given the operands we 2129 // have. 2130 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2131 unsigned DiagOffs; 2132 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2133 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2134 << AsmString->getSourceRange(); 2135 return StmtError(); 2136 } 2137 2138 // Validate tied input operands for type mismatches. 2139 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2140 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2141 2142 // If this is a tied constraint, verify that the output and input have 2143 // either exactly the same type, or that they are int/ptr operands with the 2144 // same size (int/long, int*/long, are ok etc). 2145 if (!Info.hasTiedOperand()) continue; 2146 2147 unsigned TiedTo = Info.getTiedOperand(); 2148 unsigned InputOpNo = i+NumOutputs; 2149 Expr *OutputExpr = Exprs[TiedTo]; 2150 Expr *InputExpr = Exprs[InputOpNo]; 2151 2152 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2153 continue; 2154 2155 QualType InTy = InputExpr->getType(); 2156 QualType OutTy = OutputExpr->getType(); 2157 if (Context.hasSameType(InTy, OutTy)) 2158 continue; // All types can be tied to themselves. 2159 2160 // Decide if the input and output are in the same domain (integer/ptr or 2161 // floating point. 2162 enum AsmDomain { 2163 AD_Int, AD_FP, AD_Other 2164 } InputDomain, OutputDomain; 2165 2166 if (InTy->isIntegerType() || InTy->isPointerType()) 2167 InputDomain = AD_Int; 2168 else if (InTy->isRealFloatingType()) 2169 InputDomain = AD_FP; 2170 else 2171 InputDomain = AD_Other; 2172 2173 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2174 OutputDomain = AD_Int; 2175 else if (OutTy->isRealFloatingType()) 2176 OutputDomain = AD_FP; 2177 else 2178 OutputDomain = AD_Other; 2179 2180 // They are ok if they are the same size and in the same domain. This 2181 // allows tying things like: 2182 // void* to int* 2183 // void* to int if they are the same size. 2184 // double to long double if they are the same size. 2185 // 2186 uint64_t OutSize = Context.getTypeSize(OutTy); 2187 uint64_t InSize = Context.getTypeSize(InTy); 2188 if (OutSize == InSize && InputDomain == OutputDomain && 2189 InputDomain != AD_Other) 2190 continue; 2191 2192 // If the smaller input/output operand is not mentioned in the asm string, 2193 // then we can promote the smaller one to a larger input and the asm string 2194 // won't notice. 2195 bool SmallerValueMentioned = false; 2196 2197 // If this is a reference to the input and if the input was the smaller 2198 // one, then we have to reject this asm. 2199 if (isOperandMentioned(InputOpNo, Pieces)) { 2200 // This is a use in the asm string of the smaller operand. Since we 2201 // codegen this by promoting to a wider value, the asm will get printed 2202 // "wrong". 2203 SmallerValueMentioned |= InSize < OutSize; 2204 } 2205 if (isOperandMentioned(TiedTo, Pieces)) { 2206 // If this is a reference to the output, and if the output is the larger 2207 // value, then it's ok because we'll promote the input to the larger type. 2208 SmallerValueMentioned |= OutSize < InSize; 2209 } 2210 2211 // If the smaller value wasn't mentioned in the asm string, and if the 2212 // output was a register, just extend the shorter one to the size of the 2213 // larger one. 2214 if (!SmallerValueMentioned && InputDomain != AD_Other && 2215 OutputConstraintInfos[TiedTo].allowsRegister()) 2216 continue; 2217 2218 // Either both of the operands were mentioned or the smaller one was 2219 // mentioned. One more special case that we'll allow: if the tied input is 2220 // integer, unmentioned, and is a constant, then we'll allow truncating it 2221 // down to the size of the destination. 2222 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2223 !isOperandMentioned(InputOpNo, Pieces) && 2224 InputExpr->isEvaluatable(Context)) { 2225 CastKind castKind = 2226 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2227 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2228 Exprs[InputOpNo] = InputExpr; 2229 NS->setInputExpr(i, InputExpr); 2230 continue; 2231 } 2232 2233 Diag(InputExpr->getLocStart(), 2234 diag::err_asm_tying_incompatible_types) 2235 << InTy << OutTy << OutputExpr->getSourceRange() 2236 << InputExpr->getSourceRange(); 2237 return StmtError(); 2238 } 2239 2240 return Owned(NS); 2241} 2242 2243StmtResult 2244Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2245 SourceLocation RParen, Decl *Parm, 2246 Stmt *Body) { 2247 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2248 if (Var && Var->isInvalidDecl()) 2249 return StmtError(); 2250 2251 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2252} 2253 2254StmtResult 2255Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2256 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2257} 2258 2259StmtResult 2260Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2261 MultiStmtArg CatchStmts, Stmt *Finally) { 2262 if (!getLangOptions().ObjCExceptions) 2263 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2264 2265 getCurFunction()->setHasBranchProtectedScope(); 2266 unsigned NumCatchStmts = CatchStmts.size(); 2267 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2268 CatchStmts.release(), 2269 NumCatchStmts, 2270 Finally)); 2271} 2272 2273StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 2274 Expr *Throw) { 2275 if (Throw) { 2276 Throw = MaybeCreateExprWithCleanups(Throw); 2277 ExprResult Result = DefaultLvalueConversion(Throw); 2278 if (Result.isInvalid()) 2279 return StmtError(); 2280 2281 Throw = Result.take(); 2282 QualType ThrowType = Throw->getType(); 2283 // Make sure the expression type is an ObjC pointer or "void *". 2284 if (!ThrowType->isDependentType() && 2285 !ThrowType->isObjCObjectPointerType()) { 2286 const PointerType *PT = ThrowType->getAs<PointerType>(); 2287 if (!PT || !PT->getPointeeType()->isVoidType()) 2288 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2289 << Throw->getType() << Throw->getSourceRange()); 2290 } 2291 } 2292 2293 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2294} 2295 2296StmtResult 2297Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2298 Scope *CurScope) { 2299 if (!getLangOptions().ObjCExceptions) 2300 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2301 2302 if (!Throw) { 2303 // @throw without an expression designates a rethrow (which much occur 2304 // in the context of an @catch clause). 2305 Scope *AtCatchParent = CurScope; 2306 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2307 AtCatchParent = AtCatchParent->getParent(); 2308 if (!AtCatchParent) 2309 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2310 } 2311 2312 return BuildObjCAtThrowStmt(AtLoc, Throw); 2313} 2314 2315ExprResult 2316Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 2317 ExprResult result = DefaultLvalueConversion(operand); 2318 if (result.isInvalid()) 2319 return ExprError(); 2320 operand = result.take(); 2321 2322 // Make sure the expression type is an ObjC pointer or "void *". 2323 QualType type = operand->getType(); 2324 if (!type->isDependentType() && 2325 !type->isObjCObjectPointerType()) { 2326 const PointerType *pointerType = type->getAs<PointerType>(); 2327 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 2328 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 2329 << type << operand->getSourceRange(); 2330 } 2331 2332 // The operand to @synchronized is a full-expression. 2333 return MaybeCreateExprWithCleanups(operand); 2334} 2335 2336StmtResult 2337Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2338 Stmt *SyncBody) { 2339 // We can't jump into or indirect-jump out of a @synchronized block. 2340 getCurFunction()->setHasBranchProtectedScope(); 2341 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2342} 2343 2344/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2345/// and creates a proper catch handler from them. 2346StmtResult 2347Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2348 Stmt *HandlerBlock) { 2349 // There's nothing to test that ActOnExceptionDecl didn't already test. 2350 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2351 cast_or_null<VarDecl>(ExDecl), 2352 HandlerBlock)); 2353} 2354 2355StmtResult 2356Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2357 getCurFunction()->setHasBranchProtectedScope(); 2358 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2359} 2360 2361namespace { 2362 2363class TypeWithHandler { 2364 QualType t; 2365 CXXCatchStmt *stmt; 2366public: 2367 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2368 : t(type), stmt(statement) {} 2369 2370 // An arbitrary order is fine as long as it places identical 2371 // types next to each other. 2372 bool operator<(const TypeWithHandler &y) const { 2373 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2374 return true; 2375 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2376 return false; 2377 else 2378 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2379 } 2380 2381 bool operator==(const TypeWithHandler& other) const { 2382 return t == other.t; 2383 } 2384 2385 CXXCatchStmt *getCatchStmt() const { return stmt; } 2386 SourceLocation getTypeSpecStartLoc() const { 2387 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2388 } 2389}; 2390 2391} 2392 2393/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2394/// handlers and creates a try statement from them. 2395StmtResult 2396Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2397 MultiStmtArg RawHandlers) { 2398 // Don't report an error if 'try' is used in system headers. 2399 if (!getLangOptions().CXXExceptions && 2400 !getSourceManager().isInSystemHeader(TryLoc)) 2401 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2402 2403 unsigned NumHandlers = RawHandlers.size(); 2404 assert(NumHandlers > 0 && 2405 "The parser shouldn't call this if there are no handlers."); 2406 Stmt **Handlers = RawHandlers.get(); 2407 2408 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2409 2410 for (unsigned i = 0; i < NumHandlers; ++i) { 2411 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2412 if (!Handler->getExceptionDecl()) { 2413 if (i < NumHandlers - 1) 2414 return StmtError(Diag(Handler->getLocStart(), 2415 diag::err_early_catch_all)); 2416 2417 continue; 2418 } 2419 2420 const QualType CaughtType = Handler->getCaughtType(); 2421 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2422 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2423 } 2424 2425 // Detect handlers for the same type as an earlier one. 2426 if (NumHandlers > 1) { 2427 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2428 2429 TypeWithHandler prev = TypesWithHandlers[0]; 2430 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2431 TypeWithHandler curr = TypesWithHandlers[i]; 2432 2433 if (curr == prev) { 2434 Diag(curr.getTypeSpecStartLoc(), 2435 diag::warn_exception_caught_by_earlier_handler) 2436 << curr.getCatchStmt()->getCaughtType().getAsString(); 2437 Diag(prev.getTypeSpecStartLoc(), 2438 diag::note_previous_exception_handler) 2439 << prev.getCatchStmt()->getCaughtType().getAsString(); 2440 } 2441 2442 prev = curr; 2443 } 2444 } 2445 2446 getCurFunction()->setHasBranchProtectedScope(); 2447 2448 // FIXME: We should detect handlers that cannot catch anything because an 2449 // earlier handler catches a superclass. Need to find a method that is not 2450 // quadratic for this. 2451 // Neither of these are explicitly forbidden, but every compiler detects them 2452 // and warns. 2453 2454 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2455 Handlers, NumHandlers)); 2456} 2457 2458StmtResult 2459Sema::ActOnSEHTryBlock(bool IsCXXTry, 2460 SourceLocation TryLoc, 2461 Stmt *TryBlock, 2462 Stmt *Handler) { 2463 assert(TryBlock && Handler); 2464 2465 getCurFunction()->setHasBranchProtectedScope(); 2466 2467 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2468} 2469 2470StmtResult 2471Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2472 Expr *FilterExpr, 2473 Stmt *Block) { 2474 assert(FilterExpr && Block); 2475 2476 if(!FilterExpr->getType()->isIntegerType()) { 2477 return StmtError(Diag(FilterExpr->getExprLoc(), 2478 diag::err_filter_expression_integral) 2479 << FilterExpr->getType()); 2480 } 2481 2482 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2483} 2484 2485StmtResult 2486Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2487 Stmt *Block) { 2488 assert(Block); 2489 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2490} 2491 2492StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 2493 bool IsIfExists, 2494 NestedNameSpecifierLoc QualifierLoc, 2495 DeclarationNameInfo NameInfo, 2496 Stmt *Nested) 2497{ 2498 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 2499 QualifierLoc, NameInfo, 2500 cast<CompoundStmt>(Nested)); 2501} 2502 2503 2504StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 2505 bool IsIfExists, 2506 CXXScopeSpec &SS, 2507 UnqualifiedId &Name, 2508 Stmt *Nested) { 2509 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 2510 SS.getWithLocInContext(Context), 2511 GetNameFromUnqualifiedId(Name), 2512 Nested); 2513} 2514