SemaStmt.cpp revision 31ceb61172bca7ebc3fb90e9125864c7a29c55c0
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements semantic analysis for statements. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Sema/SemaInternal.h" 15#include "clang/Sema/Scope.h" 16#include "clang/Sema/ScopeInfo.h" 17#include "clang/Sema/Initialization.h" 18#include "clang/Sema/Lookup.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/CharUnits.h" 21#include "clang/AST/DeclObjC.h" 22#include "clang/AST/ExprCXX.h" 23#include "clang/AST/ExprObjC.h" 24#include "clang/AST/StmtObjC.h" 25#include "clang/AST/StmtCXX.h" 26#include "clang/AST/TypeLoc.h" 27#include "clang/Lex/Preprocessor.h" 28#include "clang/Basic/TargetInfo.h" 29#include "llvm/ADT/ArrayRef.h" 30#include "llvm/ADT/STLExtras.h" 31#include "llvm/ADT/SmallVector.h" 32using namespace clang; 33using namespace sema; 34 35StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 36 Expr *E = expr.get(); 37 if (!E) // FIXME: FullExprArg has no error state? 38 return StmtError(); 39 40 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 41 // void expression for its side effects. Conversion to void allows any 42 // operand, even incomplete types. 43 44 // Same thing in for stmt first clause (when expr) and third clause. 45 return Owned(static_cast<Stmt*>(E)); 46} 47 48 49StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, 50 bool HasLeadingEmptyMacro) { 51 return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro)); 52} 53 54StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 55 SourceLocation EndLoc) { 56 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 57 58 // If we have an invalid decl, just return an error. 59 if (DG.isNull()) return StmtError(); 60 61 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 62} 63 64void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 65 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 66 67 // If we have an invalid decl, just return. 68 if (DG.isNull() || !DG.isSingleDecl()) return; 69 VarDecl *var = cast<VarDecl>(DG.getSingleDecl()); 70 71 // suppress any potential 'unused variable' warning. 72 var->setUsed(); 73 74 // foreach variables are never actually initialized in the way that 75 // the parser came up with. 76 var->setInit(0); 77 78 // In ARC, we don't need to retain the iteration variable of a fast 79 // enumeration loop. Rather than actually trying to catch that 80 // during declaration processing, we remove the consequences here. 81 if (getLangOptions().ObjCAutoRefCount) { 82 QualType type = var->getType(); 83 84 // Only do this if we inferred the lifetime. Inferred lifetime 85 // will show up as a local qualifier because explicit lifetime 86 // should have shown up as an AttributedType instead. 87 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { 88 // Add 'const' and mark the variable as pseudo-strong. 89 var->setType(type.withConst()); 90 var->setARCPseudoStrong(true); 91 } 92 } 93} 94 95/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='. 96/// 97/// Adding a cast to void (or other expression wrappers) will prevent the 98/// warning from firing. 99static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) { 100 SourceLocation Loc; 101 bool IsNotEqual, CanAssign; 102 103 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) { 104 if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE) 105 return false; 106 107 Loc = Op->getOperatorLoc(); 108 IsNotEqual = Op->getOpcode() == BO_NE; 109 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue(); 110 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) { 111 if (Op->getOperator() != OO_EqualEqual && 112 Op->getOperator() != OO_ExclaimEqual) 113 return false; 114 115 Loc = Op->getOperatorLoc(); 116 IsNotEqual = Op->getOperator() == OO_ExclaimEqual; 117 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue(); 118 } else { 119 // Not a typo-prone comparison. 120 return false; 121 } 122 123 // Suppress warnings when the operator, suspicious as it may be, comes from 124 // a macro expansion. 125 if (Loc.isMacroID()) 126 return false; 127 128 S.Diag(Loc, diag::warn_unused_comparison) 129 << (unsigned)IsNotEqual << E->getSourceRange(); 130 131 // If the LHS is a plausible entity to assign to, provide a fixit hint to 132 // correct common typos. 133 if (CanAssign) { 134 if (IsNotEqual) 135 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign) 136 << FixItHint::CreateReplacement(Loc, "|="); 137 else 138 S.Diag(Loc, diag::note_equality_comparison_to_assign) 139 << FixItHint::CreateReplacement(Loc, "="); 140 } 141 142 return true; 143} 144 145void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 146 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 147 return DiagnoseUnusedExprResult(Label->getSubStmt()); 148 149 const Expr *E = dyn_cast_or_null<Expr>(S); 150 if (!E) 151 return; 152 153 SourceLocation Loc; 154 SourceRange R1, R2; 155 if (SourceMgr.isInSystemMacro(E->getExprLoc()) || 156 !E->isUnusedResultAWarning(Loc, R1, R2, Context)) 157 return; 158 159 // Okay, we have an unused result. Depending on what the base expression is, 160 // we might want to make a more specific diagnostic. Check for one of these 161 // cases now. 162 unsigned DiagID = diag::warn_unused_expr; 163 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 164 E = Temps->getSubExpr(); 165 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 166 E = TempExpr->getSubExpr(); 167 168 if (DiagnoseUnusedComparison(*this, E)) 169 return; 170 171 E = E->IgnoreParenImpCasts(); 172 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 173 if (E->getType()->isVoidType()) 174 return; 175 176 // If the callee has attribute pure, const, or warn_unused_result, warn with 177 // a more specific message to make it clear what is happening. 178 if (const Decl *FD = CE->getCalleeDecl()) { 179 if (FD->getAttr<WarnUnusedResultAttr>()) { 180 Diag(Loc, diag::warn_unused_result) << R1 << R2; 181 return; 182 } 183 if (FD->getAttr<PureAttr>()) { 184 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 185 return; 186 } 187 if (FD->getAttr<ConstAttr>()) { 188 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 189 return; 190 } 191 } 192 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 193 if (getLangOptions().ObjCAutoRefCount && ME->isDelegateInitCall()) { 194 Diag(Loc, diag::err_arc_unused_init_message) << R1; 195 return; 196 } 197 const ObjCMethodDecl *MD = ME->getMethodDecl(); 198 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 199 Diag(Loc, diag::warn_unused_result) << R1 << R2; 200 return; 201 } 202 } else if (isa<PseudoObjectExpr>(E)) { 203 DiagID = diag::warn_unused_property_expr; 204 } else if (const CXXFunctionalCastExpr *FC 205 = dyn_cast<CXXFunctionalCastExpr>(E)) { 206 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 207 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 208 return; 209 } 210 // Diagnose "(void*) blah" as a typo for "(void) blah". 211 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 212 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 213 QualType T = TI->getType(); 214 215 // We really do want to use the non-canonical type here. 216 if (T == Context.VoidPtrTy) { 217 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 218 219 Diag(Loc, diag::warn_unused_voidptr) 220 << FixItHint::CreateRemoval(TL.getStarLoc()); 221 return; 222 } 223 } 224 225 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 226} 227 228StmtResult 229Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 230 MultiStmtArg elts, bool isStmtExpr) { 231 unsigned NumElts = elts.size(); 232 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 233 // If we're in C89 mode, check that we don't have any decls after stmts. If 234 // so, emit an extension diagnostic. 235 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 236 // Note that __extension__ can be around a decl. 237 unsigned i = 0; 238 // Skip over all declarations. 239 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 240 /*empty*/; 241 242 // We found the end of the list or a statement. Scan for another declstmt. 243 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 244 /*empty*/; 245 246 if (i != NumElts) { 247 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 248 Diag(D->getLocation(), diag::ext_mixed_decls_code); 249 } 250 } 251 // Warn about unused expressions in statements. 252 for (unsigned i = 0; i != NumElts; ++i) { 253 // Ignore statements that are last in a statement expression. 254 if (isStmtExpr && i == NumElts - 1) 255 continue; 256 257 DiagnoseUnusedExprResult(Elts[i]); 258 } 259 260 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 261} 262 263StmtResult 264Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 265 SourceLocation DotDotDotLoc, Expr *RHSVal, 266 SourceLocation ColonLoc) { 267 assert((LHSVal != 0) && "missing expression in case statement"); 268 269 if (getCurFunction()->SwitchStack.empty()) { 270 Diag(CaseLoc, diag::err_case_not_in_switch); 271 return StmtError(); 272 } 273 274 if (!getLangOptions().CPlusPlus0x) { 275 // C99 6.8.4.2p3: The expression shall be an integer constant. 276 // However, GCC allows any evaluatable integer expression. 277 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 278 VerifyIntegerConstantExpression(LHSVal)) 279 return StmtError(); 280 281 // GCC extension: The expression shall be an integer constant. 282 283 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 284 VerifyIntegerConstantExpression(RHSVal)) { 285 RHSVal = 0; // Recover by just forgetting about it. 286 } 287 } 288 289 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 290 ColonLoc); 291 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 292 return Owned(CS); 293} 294 295/// ActOnCaseStmtBody - This installs a statement as the body of a case. 296void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 297 DiagnoseUnusedExprResult(SubStmt); 298 299 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 300 CS->setSubStmt(SubStmt); 301} 302 303StmtResult 304Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 305 Stmt *SubStmt, Scope *CurScope) { 306 DiagnoseUnusedExprResult(SubStmt); 307 308 if (getCurFunction()->SwitchStack.empty()) { 309 Diag(DefaultLoc, diag::err_default_not_in_switch); 310 return Owned(SubStmt); 311 } 312 313 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 314 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 315 return Owned(DS); 316} 317 318StmtResult 319Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 320 SourceLocation ColonLoc, Stmt *SubStmt) { 321 322 // If the label was multiply defined, reject it now. 323 if (TheDecl->getStmt()) { 324 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 325 Diag(TheDecl->getLocation(), diag::note_previous_definition); 326 return Owned(SubStmt); 327 } 328 329 // Otherwise, things are good. Fill in the declaration and return it. 330 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 331 TheDecl->setStmt(LS); 332 if (!TheDecl->isGnuLocal()) 333 TheDecl->setLocation(IdentLoc); 334 return Owned(LS); 335} 336 337StmtResult 338Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 339 Stmt *thenStmt, SourceLocation ElseLoc, 340 Stmt *elseStmt) { 341 ExprResult CondResult(CondVal.release()); 342 343 VarDecl *ConditionVar = 0; 344 if (CondVar) { 345 ConditionVar = cast<VarDecl>(CondVar); 346 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 347 if (CondResult.isInvalid()) 348 return StmtError(); 349 } 350 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 351 if (!ConditionExpr) 352 return StmtError(); 353 354 DiagnoseUnusedExprResult(thenStmt); 355 356 // Warn if the if block has a null body without an else value. 357 // this helps prevent bugs due to typos, such as 358 // if (condition); 359 // do_stuff(); 360 // 361 if (!elseStmt) { 362 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 363 // But do not warn if the body is a macro that expands to nothing, e.g: 364 // 365 // #define CALL(x) 366 // if (condition) 367 // CALL(0); 368 // 369 if (!stmt->hasLeadingEmptyMacro()) 370 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 371 } 372 373 DiagnoseUnusedExprResult(elseStmt); 374 375 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 376 thenStmt, ElseLoc, elseStmt)); 377} 378 379/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 380/// the specified width and sign. If an overflow occurs, detect it and emit 381/// the specified diagnostic. 382void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 383 unsigned NewWidth, bool NewSign, 384 SourceLocation Loc, 385 unsigned DiagID) { 386 // Perform a conversion to the promoted condition type if needed. 387 if (NewWidth > Val.getBitWidth()) { 388 // If this is an extension, just do it. 389 Val = Val.extend(NewWidth); 390 Val.setIsSigned(NewSign); 391 392 // If the input was signed and negative and the output is 393 // unsigned, don't bother to warn: this is implementation-defined 394 // behavior. 395 // FIXME: Introduce a second, default-ignored warning for this case? 396 } else if (NewWidth < Val.getBitWidth()) { 397 // If this is a truncation, check for overflow. 398 llvm::APSInt ConvVal(Val); 399 ConvVal = ConvVal.trunc(NewWidth); 400 ConvVal.setIsSigned(NewSign); 401 ConvVal = ConvVal.extend(Val.getBitWidth()); 402 ConvVal.setIsSigned(Val.isSigned()); 403 if (ConvVal != Val) 404 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 405 406 // Regardless of whether a diagnostic was emitted, really do the 407 // truncation. 408 Val = Val.trunc(NewWidth); 409 Val.setIsSigned(NewSign); 410 } else if (NewSign != Val.isSigned()) { 411 // Convert the sign to match the sign of the condition. This can cause 412 // overflow as well: unsigned(INTMIN) 413 // We don't diagnose this overflow, because it is implementation-defined 414 // behavior. 415 // FIXME: Introduce a second, default-ignored warning for this case? 416 llvm::APSInt OldVal(Val); 417 Val.setIsSigned(NewSign); 418 } 419} 420 421namespace { 422 struct CaseCompareFunctor { 423 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 424 const llvm::APSInt &RHS) { 425 return LHS.first < RHS; 426 } 427 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 428 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 429 return LHS.first < RHS.first; 430 } 431 bool operator()(const llvm::APSInt &LHS, 432 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 433 return LHS < RHS.first; 434 } 435 }; 436} 437 438/// CmpCaseVals - Comparison predicate for sorting case values. 439/// 440static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 441 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 442 if (lhs.first < rhs.first) 443 return true; 444 445 if (lhs.first == rhs.first && 446 lhs.second->getCaseLoc().getRawEncoding() 447 < rhs.second->getCaseLoc().getRawEncoding()) 448 return true; 449 return false; 450} 451 452/// CmpEnumVals - Comparison predicate for sorting enumeration values. 453/// 454static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 455 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 456{ 457 return lhs.first < rhs.first; 458} 459 460/// EqEnumVals - Comparison preficate for uniqing enumeration values. 461/// 462static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 463 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 464{ 465 return lhs.first == rhs.first; 466} 467 468/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 469/// potentially integral-promoted expression @p expr. 470static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 471 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 472 expr = cleanups->getSubExpr(); 473 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 474 if (impcast->getCastKind() != CK_IntegralCast) break; 475 expr = impcast->getSubExpr(); 476 } 477 return expr->getType(); 478} 479 480StmtResult 481Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 482 Decl *CondVar) { 483 ExprResult CondResult; 484 485 VarDecl *ConditionVar = 0; 486 if (CondVar) { 487 ConditionVar = cast<VarDecl>(CondVar); 488 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 489 if (CondResult.isInvalid()) 490 return StmtError(); 491 492 Cond = CondResult.release(); 493 } 494 495 if (!Cond) 496 return StmtError(); 497 498 CondResult = CheckPlaceholderExpr(Cond); 499 if (CondResult.isInvalid()) 500 return StmtError(); 501 502 CondResult 503 = ConvertToIntegralOrEnumerationType(SwitchLoc, CondResult.take(), 504 PDiag(diag::err_typecheck_statement_requires_integer), 505 PDiag(diag::err_switch_incomplete_class_type) 506 << Cond->getSourceRange(), 507 PDiag(diag::err_switch_explicit_conversion), 508 PDiag(diag::note_switch_conversion), 509 PDiag(diag::err_switch_multiple_conversions), 510 PDiag(diag::note_switch_conversion), 511 PDiag(0)); 512 if (CondResult.isInvalid()) return StmtError(); 513 Cond = CondResult.take(); 514 515 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 516 CondResult = UsualUnaryConversions(Cond); 517 if (CondResult.isInvalid()) return StmtError(); 518 Cond = CondResult.take(); 519 520 if (!CondVar) { 521 CheckImplicitConversions(Cond, SwitchLoc); 522 CondResult = MaybeCreateExprWithCleanups(Cond); 523 if (CondResult.isInvalid()) 524 return StmtError(); 525 Cond = CondResult.take(); 526 } 527 528 getCurFunction()->setHasBranchIntoScope(); 529 530 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 531 getCurFunction()->SwitchStack.push_back(SS); 532 return Owned(SS); 533} 534 535static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 536 if (Val.getBitWidth() < BitWidth) 537 Val = Val.extend(BitWidth); 538 else if (Val.getBitWidth() > BitWidth) 539 Val = Val.trunc(BitWidth); 540 Val.setIsSigned(IsSigned); 541} 542 543StmtResult 544Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 545 Stmt *BodyStmt) { 546 SwitchStmt *SS = cast<SwitchStmt>(Switch); 547 assert(SS == getCurFunction()->SwitchStack.back() && 548 "switch stack missing push/pop!"); 549 550 SS->setBody(BodyStmt, SwitchLoc); 551 getCurFunction()->SwitchStack.pop_back(); 552 553 Expr *CondExpr = SS->getCond(); 554 if (!CondExpr) return StmtError(); 555 556 QualType CondType = CondExpr->getType(); 557 558 Expr *CondExprBeforePromotion = CondExpr; 559 QualType CondTypeBeforePromotion = 560 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 561 562 // C++ 6.4.2.p2: 563 // Integral promotions are performed (on the switch condition). 564 // 565 // A case value unrepresentable by the original switch condition 566 // type (before the promotion) doesn't make sense, even when it can 567 // be represented by the promoted type. Therefore we need to find 568 // the pre-promotion type of the switch condition. 569 if (!CondExpr->isTypeDependent()) { 570 // We have already converted the expression to an integral or enumeration 571 // type, when we started the switch statement. If we don't have an 572 // appropriate type now, just return an error. 573 if (!CondType->isIntegralOrEnumerationType()) 574 return StmtError(); 575 576 if (CondExpr->isKnownToHaveBooleanValue()) { 577 // switch(bool_expr) {...} is often a programmer error, e.g. 578 // switch(n && mask) { ... } // Doh - should be "n & mask". 579 // One can always use an if statement instead of switch(bool_expr). 580 Diag(SwitchLoc, diag::warn_bool_switch_condition) 581 << CondExpr->getSourceRange(); 582 } 583 } 584 585 // Get the bitwidth of the switched-on value before promotions. We must 586 // convert the integer case values to this width before comparison. 587 bool HasDependentValue 588 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 589 unsigned CondWidth 590 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 591 bool CondIsSigned 592 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 593 594 // Accumulate all of the case values in a vector so that we can sort them 595 // and detect duplicates. This vector contains the APInt for the case after 596 // it has been converted to the condition type. 597 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 598 CaseValsTy CaseVals; 599 600 // Keep track of any GNU case ranges we see. The APSInt is the low value. 601 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 602 CaseRangesTy CaseRanges; 603 604 DefaultStmt *TheDefaultStmt = 0; 605 606 bool CaseListIsErroneous = false; 607 608 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 609 SC = SC->getNextSwitchCase()) { 610 611 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 612 if (TheDefaultStmt) { 613 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 614 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 615 616 // FIXME: Remove the default statement from the switch block so that 617 // we'll return a valid AST. This requires recursing down the AST and 618 // finding it, not something we are set up to do right now. For now, 619 // just lop the entire switch stmt out of the AST. 620 CaseListIsErroneous = true; 621 } 622 TheDefaultStmt = DS; 623 624 } else { 625 CaseStmt *CS = cast<CaseStmt>(SC); 626 627 Expr *Lo = CS->getLHS(); 628 629 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 630 HasDependentValue = true; 631 break; 632 } 633 634 llvm::APSInt LoVal; 635 636 if (getLangOptions().CPlusPlus0x) { 637 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 638 // constant expression of the promoted type of the switch condition. 639 ExprResult ConvLo = 640 CheckConvertedConstantExpression(Lo, CondType, LoVal, CCEK_CaseValue); 641 if (ConvLo.isInvalid()) { 642 CaseListIsErroneous = true; 643 continue; 644 } 645 Lo = ConvLo.take(); 646 } else { 647 // We already verified that the expression has a i-c-e value (C99 648 // 6.8.4.2p3) - get that value now. 649 LoVal = Lo->EvaluateKnownConstInt(Context); 650 651 // If the LHS is not the same type as the condition, insert an implicit 652 // cast. 653 Lo = DefaultLvalueConversion(Lo).take(); 654 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 655 } 656 657 // Convert the value to the same width/sign as the condition had prior to 658 // integral promotions. 659 // 660 // FIXME: This causes us to reject valid code: 661 // switch ((char)c) { case 256: case 0: return 0; } 662 // Here we claim there is a duplicated condition value, but there is not. 663 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 664 Lo->getLocStart(), 665 diag::warn_case_value_overflow); 666 667 CS->setLHS(Lo); 668 669 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 670 if (CS->getRHS()) { 671 if (CS->getRHS()->isTypeDependent() || 672 CS->getRHS()->isValueDependent()) { 673 HasDependentValue = true; 674 break; 675 } 676 CaseRanges.push_back(std::make_pair(LoVal, CS)); 677 } else 678 CaseVals.push_back(std::make_pair(LoVal, CS)); 679 } 680 } 681 682 if (!HasDependentValue) { 683 // If we don't have a default statement, check whether the 684 // condition is constant. 685 llvm::APSInt ConstantCondValue; 686 bool HasConstantCond = false; 687 if (!HasDependentValue && !TheDefaultStmt) { 688 HasConstantCond 689 = CondExprBeforePromotion->EvaluateAsInt(ConstantCondValue, Context, 690 Expr::SE_AllowSideEffects); 691 assert(!HasConstantCond || 692 (ConstantCondValue.getBitWidth() == CondWidth && 693 ConstantCondValue.isSigned() == CondIsSigned)); 694 } 695 bool ShouldCheckConstantCond = HasConstantCond; 696 697 // Sort all the scalar case values so we can easily detect duplicates. 698 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 699 700 if (!CaseVals.empty()) { 701 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 702 if (ShouldCheckConstantCond && 703 CaseVals[i].first == ConstantCondValue) 704 ShouldCheckConstantCond = false; 705 706 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 707 // If we have a duplicate, report it. 708 Diag(CaseVals[i].second->getLHS()->getLocStart(), 709 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 710 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 711 diag::note_duplicate_case_prev); 712 // FIXME: We really want to remove the bogus case stmt from the 713 // substmt, but we have no way to do this right now. 714 CaseListIsErroneous = true; 715 } 716 } 717 } 718 719 // Detect duplicate case ranges, which usually don't exist at all in 720 // the first place. 721 if (!CaseRanges.empty()) { 722 // Sort all the case ranges by their low value so we can easily detect 723 // overlaps between ranges. 724 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 725 726 // Scan the ranges, computing the high values and removing empty ranges. 727 std::vector<llvm::APSInt> HiVals; 728 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 729 llvm::APSInt &LoVal = CaseRanges[i].first; 730 CaseStmt *CR = CaseRanges[i].second; 731 Expr *Hi = CR->getRHS(); 732 llvm::APSInt HiVal; 733 734 if (getLangOptions().CPlusPlus0x) { 735 // C++11 [stmt.switch]p2: the constant-expression shall be a converted 736 // constant expression of the promoted type of the switch condition. 737 ExprResult ConvHi = 738 CheckConvertedConstantExpression(Hi, CondType, HiVal, 739 CCEK_CaseValue); 740 if (ConvHi.isInvalid()) { 741 CaseListIsErroneous = true; 742 continue; 743 } 744 Hi = ConvHi.take(); 745 } else { 746 HiVal = Hi->EvaluateKnownConstInt(Context); 747 748 // If the RHS is not the same type as the condition, insert an 749 // implicit cast. 750 Hi = DefaultLvalueConversion(Hi).take(); 751 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 752 } 753 754 // Convert the value to the same width/sign as the condition. 755 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 756 Hi->getLocStart(), 757 diag::warn_case_value_overflow); 758 759 CR->setRHS(Hi); 760 761 // If the low value is bigger than the high value, the case is empty. 762 if (LoVal > HiVal) { 763 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 764 << SourceRange(CR->getLHS()->getLocStart(), 765 Hi->getLocEnd()); 766 CaseRanges.erase(CaseRanges.begin()+i); 767 --i, --e; 768 continue; 769 } 770 771 if (ShouldCheckConstantCond && 772 LoVal <= ConstantCondValue && 773 ConstantCondValue <= HiVal) 774 ShouldCheckConstantCond = false; 775 776 HiVals.push_back(HiVal); 777 } 778 779 // Rescan the ranges, looking for overlap with singleton values and other 780 // ranges. Since the range list is sorted, we only need to compare case 781 // ranges with their neighbors. 782 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 783 llvm::APSInt &CRLo = CaseRanges[i].first; 784 llvm::APSInt &CRHi = HiVals[i]; 785 CaseStmt *CR = CaseRanges[i].second; 786 787 // Check to see whether the case range overlaps with any 788 // singleton cases. 789 CaseStmt *OverlapStmt = 0; 790 llvm::APSInt OverlapVal(32); 791 792 // Find the smallest value >= the lower bound. If I is in the 793 // case range, then we have overlap. 794 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 795 CaseVals.end(), CRLo, 796 CaseCompareFunctor()); 797 if (I != CaseVals.end() && I->first < CRHi) { 798 OverlapVal = I->first; // Found overlap with scalar. 799 OverlapStmt = I->second; 800 } 801 802 // Find the smallest value bigger than the upper bound. 803 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 804 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 805 OverlapVal = (I-1)->first; // Found overlap with scalar. 806 OverlapStmt = (I-1)->second; 807 } 808 809 // Check to see if this case stmt overlaps with the subsequent 810 // case range. 811 if (i && CRLo <= HiVals[i-1]) { 812 OverlapVal = HiVals[i-1]; // Found overlap with range. 813 OverlapStmt = CaseRanges[i-1].second; 814 } 815 816 if (OverlapStmt) { 817 // If we have a duplicate, report it. 818 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 819 << OverlapVal.toString(10); 820 Diag(OverlapStmt->getLHS()->getLocStart(), 821 diag::note_duplicate_case_prev); 822 // FIXME: We really want to remove the bogus case stmt from the 823 // substmt, but we have no way to do this right now. 824 CaseListIsErroneous = true; 825 } 826 } 827 } 828 829 // Complain if we have a constant condition and we didn't find a match. 830 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 831 // TODO: it would be nice if we printed enums as enums, chars as 832 // chars, etc. 833 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 834 << ConstantCondValue.toString(10) 835 << CondExpr->getSourceRange(); 836 } 837 838 // Check to see if switch is over an Enum and handles all of its 839 // values. We only issue a warning if there is not 'default:', but 840 // we still do the analysis to preserve this information in the AST 841 // (which can be used by flow-based analyes). 842 // 843 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 844 845 // If switch has default case, then ignore it. 846 if (!CaseListIsErroneous && !HasConstantCond && ET) { 847 const EnumDecl *ED = ET->getDecl(); 848 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 849 EnumValsTy; 850 EnumValsTy EnumVals; 851 852 // Gather all enum values, set their type and sort them, 853 // allowing easier comparison with CaseVals. 854 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 855 EDI != ED->enumerator_end(); ++EDI) { 856 llvm::APSInt Val = EDI->getInitVal(); 857 AdjustAPSInt(Val, CondWidth, CondIsSigned); 858 EnumVals.push_back(std::make_pair(Val, *EDI)); 859 } 860 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 861 EnumValsTy::iterator EIend = 862 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 863 864 // See which case values aren't in enum. 865 // TODO: we might want to check whether case values are out of the 866 // enum even if we don't want to check whether all cases are handled. 867 if (!TheDefaultStmt) { 868 EnumValsTy::const_iterator EI = EnumVals.begin(); 869 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 870 CI != CaseVals.end(); CI++) { 871 while (EI != EIend && EI->first < CI->first) 872 EI++; 873 if (EI == EIend || EI->first > CI->first) 874 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 875 << ED->getDeclName(); 876 } 877 // See which of case ranges aren't in enum 878 EI = EnumVals.begin(); 879 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 880 RI != CaseRanges.end() && EI != EIend; RI++) { 881 while (EI != EIend && EI->first < RI->first) 882 EI++; 883 884 if (EI == EIend || EI->first != RI->first) { 885 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 886 << ED->getDeclName(); 887 } 888 889 llvm::APSInt Hi = 890 RI->second->getRHS()->EvaluateKnownConstInt(Context); 891 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 892 while (EI != EIend && EI->first < Hi) 893 EI++; 894 if (EI == EIend || EI->first != Hi) 895 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 896 << ED->getDeclName(); 897 } 898 } 899 900 // Check which enum vals aren't in switch 901 CaseValsTy::const_iterator CI = CaseVals.begin(); 902 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 903 bool hasCasesNotInSwitch = false; 904 905 SmallVector<DeclarationName,8> UnhandledNames; 906 907 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 908 // Drop unneeded case values 909 llvm::APSInt CIVal; 910 while (CI != CaseVals.end() && CI->first < EI->first) 911 CI++; 912 913 if (CI != CaseVals.end() && CI->first == EI->first) 914 continue; 915 916 // Drop unneeded case ranges 917 for (; RI != CaseRanges.end(); RI++) { 918 llvm::APSInt Hi = 919 RI->second->getRHS()->EvaluateKnownConstInt(Context); 920 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 921 if (EI->first <= Hi) 922 break; 923 } 924 925 if (RI == CaseRanges.end() || EI->first < RI->first) { 926 hasCasesNotInSwitch = true; 927 UnhandledNames.push_back(EI->second->getDeclName()); 928 } 929 } 930 931 if (TheDefaultStmt) { 932 if (UnhandledNames.size() == 0) 933 Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default); 934 else 935 UnhandledNames.clear(); 936 } 937 938 // Produce a nice diagnostic if multiple values aren't handled. 939 switch (UnhandledNames.size()) { 940 case 0: break; 941 case 1: 942 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 943 << UnhandledNames[0]; 944 break; 945 case 2: 946 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 947 << UnhandledNames[0] << UnhandledNames[1]; 948 break; 949 case 3: 950 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 951 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 952 break; 953 default: 954 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 955 << (unsigned)UnhandledNames.size() 956 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 957 break; 958 } 959 960 if (!hasCasesNotInSwitch) 961 SS->setAllEnumCasesCovered(); 962 } 963 } 964 965 // FIXME: If the case list was broken is some way, we don't have a good system 966 // to patch it up. Instead, just return the whole substmt as broken. 967 if (CaseListIsErroneous) 968 return StmtError(); 969 970 return Owned(SS); 971} 972 973StmtResult 974Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 975 Decl *CondVar, Stmt *Body) { 976 ExprResult CondResult(Cond.release()); 977 978 VarDecl *ConditionVar = 0; 979 if (CondVar) { 980 ConditionVar = cast<VarDecl>(CondVar); 981 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 982 if (CondResult.isInvalid()) 983 return StmtError(); 984 } 985 Expr *ConditionExpr = CondResult.take(); 986 if (!ConditionExpr) 987 return StmtError(); 988 989 DiagnoseUnusedExprResult(Body); 990 991 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 992 Body, WhileLoc)); 993} 994 995StmtResult 996Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 997 SourceLocation WhileLoc, SourceLocation CondLParen, 998 Expr *Cond, SourceLocation CondRParen) { 999 assert(Cond && "ActOnDoStmt(): missing expression"); 1000 1001 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 1002 if (CondResult.isInvalid() || CondResult.isInvalid()) 1003 return StmtError(); 1004 Cond = CondResult.take(); 1005 1006 CheckImplicitConversions(Cond, DoLoc); 1007 CondResult = MaybeCreateExprWithCleanups(Cond); 1008 if (CondResult.isInvalid()) 1009 return StmtError(); 1010 Cond = CondResult.take(); 1011 1012 DiagnoseUnusedExprResult(Body); 1013 1014 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 1015} 1016 1017StmtResult 1018Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1019 Stmt *First, FullExprArg second, Decl *secondVar, 1020 FullExprArg third, 1021 SourceLocation RParenLoc, Stmt *Body) { 1022 if (!getLangOptions().CPlusPlus) { 1023 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 1024 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1025 // declare identifiers for objects having storage class 'auto' or 1026 // 'register'. 1027 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 1028 DI!=DE; ++DI) { 1029 VarDecl *VD = dyn_cast<VarDecl>(*DI); 1030 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 1031 VD = 0; 1032 if (VD == 0) 1033 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 1034 // FIXME: mark decl erroneous! 1035 } 1036 } 1037 } 1038 1039 ExprResult SecondResult(second.release()); 1040 VarDecl *ConditionVar = 0; 1041 if (secondVar) { 1042 ConditionVar = cast<VarDecl>(secondVar); 1043 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1044 if (SecondResult.isInvalid()) 1045 return StmtError(); 1046 } 1047 1048 Expr *Third = third.release().takeAs<Expr>(); 1049 1050 DiagnoseUnusedExprResult(First); 1051 DiagnoseUnusedExprResult(Third); 1052 DiagnoseUnusedExprResult(Body); 1053 1054 return Owned(new (Context) ForStmt(Context, First, 1055 SecondResult.take(), ConditionVar, 1056 Third, Body, ForLoc, LParenLoc, 1057 RParenLoc)); 1058} 1059 1060/// In an Objective C collection iteration statement: 1061/// for (x in y) 1062/// x can be an arbitrary l-value expression. Bind it up as a 1063/// full-expression. 1064StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1065 CheckImplicitConversions(E); 1066 ExprResult Result = MaybeCreateExprWithCleanups(E); 1067 if (Result.isInvalid()) return StmtError(); 1068 return Owned(static_cast<Stmt*>(Result.get())); 1069} 1070 1071ExprResult 1072Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1073 assert(collection); 1074 1075 // Bail out early if we've got a type-dependent expression. 1076 if (collection->isTypeDependent()) return Owned(collection); 1077 1078 // Perform normal l-value conversion. 1079 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1080 if (result.isInvalid()) 1081 return ExprError(); 1082 collection = result.take(); 1083 1084 // The operand needs to have object-pointer type. 1085 // TODO: should we do a contextual conversion? 1086 const ObjCObjectPointerType *pointerType = 1087 collection->getType()->getAs<ObjCObjectPointerType>(); 1088 if (!pointerType) 1089 return Diag(forLoc, diag::err_collection_expr_type) 1090 << collection->getType() << collection->getSourceRange(); 1091 1092 // Check that the operand provides 1093 // - countByEnumeratingWithState:objects:count: 1094 const ObjCObjectType *objectType = pointerType->getObjectType(); 1095 ObjCInterfaceDecl *iface = objectType->getInterface(); 1096 1097 // If we have a forward-declared type, we can't do this check. 1098 // Under ARC, it is an error not to have a forward-declared class. 1099 if (iface && 1100 RequireCompleteType(forLoc, QualType(objectType, 0), 1101 getLangOptions().ObjCAutoRefCount 1102 ? PDiag(diag::err_arc_collection_forward) 1103 << collection->getSourceRange() 1104 : PDiag(0))) { 1105 // Otherwise, if we have any useful type information, check that 1106 // the type declares the appropriate method. 1107 } else if (iface || !objectType->qual_empty()) { 1108 IdentifierInfo *selectorIdents[] = { 1109 &Context.Idents.get("countByEnumeratingWithState"), 1110 &Context.Idents.get("objects"), 1111 &Context.Idents.get("count") 1112 }; 1113 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1114 1115 ObjCMethodDecl *method = 0; 1116 1117 // If there's an interface, look in both the public and private APIs. 1118 if (iface) { 1119 method = iface->lookupInstanceMethod(selector); 1120 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1121 } 1122 1123 // Also check protocol qualifiers. 1124 if (!method) 1125 method = LookupMethodInQualifiedType(selector, pointerType, 1126 /*instance*/ true); 1127 1128 // If we didn't find it anywhere, give up. 1129 if (!method) { 1130 Diag(forLoc, diag::warn_collection_expr_type) 1131 << collection->getType() << selector << collection->getSourceRange(); 1132 } 1133 1134 // TODO: check for an incompatible signature? 1135 } 1136 1137 // Wrap up any cleanups in the expression. 1138 return Owned(MaybeCreateExprWithCleanups(collection)); 1139} 1140 1141StmtResult 1142Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1143 SourceLocation LParenLoc, 1144 Stmt *First, Expr *Second, 1145 SourceLocation RParenLoc, Stmt *Body) { 1146 if (First) { 1147 QualType FirstType; 1148 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1149 if (!DS->isSingleDecl()) 1150 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1151 diag::err_toomany_element_decls)); 1152 1153 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1154 FirstType = D->getType(); 1155 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1156 // declare identifiers for objects having storage class 'auto' or 1157 // 'register'. 1158 if (!D->hasLocalStorage()) 1159 return StmtError(Diag(D->getLocation(), 1160 diag::err_non_variable_decl_in_for)); 1161 } else { 1162 Expr *FirstE = cast<Expr>(First); 1163 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1164 return StmtError(Diag(First->getLocStart(), 1165 diag::err_selector_element_not_lvalue) 1166 << First->getSourceRange()); 1167 1168 FirstType = static_cast<Expr*>(First)->getType(); 1169 } 1170 if (!FirstType->isDependentType() && 1171 !FirstType->isObjCObjectPointerType() && 1172 !FirstType->isBlockPointerType()) 1173 Diag(ForLoc, diag::err_selector_element_type) 1174 << FirstType << First->getSourceRange(); 1175 } 1176 1177 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1178 ForLoc, RParenLoc)); 1179} 1180 1181namespace { 1182 1183enum BeginEndFunction { 1184 BEF_begin, 1185 BEF_end 1186}; 1187 1188/// Build a variable declaration for a for-range statement. 1189static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1190 QualType Type, const char *Name) { 1191 DeclContext *DC = SemaRef.CurContext; 1192 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1193 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1194 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1195 TInfo, SC_Auto, SC_None); 1196 Decl->setImplicit(); 1197 return Decl; 1198} 1199 1200/// Finish building a variable declaration for a for-range statement. 1201/// \return true if an error occurs. 1202static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1203 SourceLocation Loc, int diag) { 1204 // Deduce the type for the iterator variable now rather than leaving it to 1205 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1206 TypeSourceInfo *InitTSI = 0; 1207 if ((!isa<InitListExpr>(Init) && Init->getType()->isVoidType()) || 1208 !SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI)) 1209 SemaRef.Diag(Loc, diag) << Init->getType(); 1210 if (!InitTSI) { 1211 Decl->setInvalidDecl(); 1212 return true; 1213 } 1214 Decl->setTypeSourceInfo(InitTSI); 1215 Decl->setType(InitTSI->getType()); 1216 1217 // In ARC, infer lifetime. 1218 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1219 // we're doing the equivalent of fast iteration. 1220 if (SemaRef.getLangOptions().ObjCAutoRefCount && 1221 SemaRef.inferObjCARCLifetime(Decl)) 1222 Decl->setInvalidDecl(); 1223 1224 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1225 /*TypeMayContainAuto=*/false); 1226 SemaRef.FinalizeDeclaration(Decl); 1227 SemaRef.CurContext->addHiddenDecl(Decl); 1228 return false; 1229} 1230 1231/// Produce a note indicating which begin/end function was implicitly called 1232/// by a C++0x for-range statement. This is often not obvious from the code, 1233/// nor from the diagnostics produced when analysing the implicit expressions 1234/// required in a for-range statement. 1235void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1236 BeginEndFunction BEF) { 1237 CallExpr *CE = dyn_cast<CallExpr>(E); 1238 if (!CE) 1239 return; 1240 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1241 if (!D) 1242 return; 1243 SourceLocation Loc = D->getLocation(); 1244 1245 std::string Description; 1246 bool IsTemplate = false; 1247 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1248 Description = SemaRef.getTemplateArgumentBindingsText( 1249 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1250 IsTemplate = true; 1251 } 1252 1253 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1254 << BEF << IsTemplate << Description << E->getType(); 1255} 1256 1257/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1258/// given LookupResult is non-empty, it is assumed to describe a member which 1259/// will be invoked. Otherwise, the function will be found via argument 1260/// dependent lookup. 1261static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1262 SourceLocation Loc, 1263 VarDecl *Decl, 1264 BeginEndFunction BEF, 1265 const DeclarationNameInfo &NameInfo, 1266 LookupResult &MemberLookup, 1267 Expr *Range) { 1268 ExprResult CallExpr; 1269 if (!MemberLookup.empty()) { 1270 ExprResult MemberRef = 1271 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1272 /*IsPtr=*/false, CXXScopeSpec(), 1273 /*Qualifier=*/0, MemberLookup, 1274 /*TemplateArgs=*/0); 1275 if (MemberRef.isInvalid()) 1276 return ExprError(); 1277 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1278 Loc, 0); 1279 if (CallExpr.isInvalid()) 1280 return ExprError(); 1281 } else { 1282 UnresolvedSet<0> FoundNames; 1283 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1284 // std is an associated namespace. 1285 UnresolvedLookupExpr *Fn = 1286 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1287 NestedNameSpecifierLoc(), NameInfo, 1288 /*NeedsADL=*/true, /*Overloaded=*/false, 1289 FoundNames.begin(), FoundNames.end(), 1290 /*LookInStdNamespace=*/true); 1291 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1292 0); 1293 if (CallExpr.isInvalid()) { 1294 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1295 << Range->getType(); 1296 return ExprError(); 1297 } 1298 } 1299 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1300 diag::err_for_range_iter_deduction_failure)) { 1301 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1302 return ExprError(); 1303 } 1304 return CallExpr; 1305} 1306 1307} 1308 1309/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1310/// 1311/// C++0x [stmt.ranged]: 1312/// A range-based for statement is equivalent to 1313/// 1314/// { 1315/// auto && __range = range-init; 1316/// for ( auto __begin = begin-expr, 1317/// __end = end-expr; 1318/// __begin != __end; 1319/// ++__begin ) { 1320/// for-range-declaration = *__begin; 1321/// statement 1322/// } 1323/// } 1324/// 1325/// The body of the loop is not available yet, since it cannot be analysed until 1326/// we have determined the type of the for-range-declaration. 1327StmtResult 1328Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1329 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1330 SourceLocation RParenLoc) { 1331 if (!First || !Range) 1332 return StmtError(); 1333 1334 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1335 assert(DS && "first part of for range not a decl stmt"); 1336 1337 if (!DS->isSingleDecl()) { 1338 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1339 return StmtError(); 1340 } 1341 if (DS->getSingleDecl()->isInvalidDecl()) 1342 return StmtError(); 1343 1344 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1345 return StmtError(); 1346 1347 // Build auto && __range = range-init 1348 SourceLocation RangeLoc = Range->getLocStart(); 1349 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1350 Context.getAutoRRefDeductType(), 1351 "__range"); 1352 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1353 diag::err_for_range_deduction_failure)) 1354 return StmtError(); 1355 1356 // Claim the type doesn't contain auto: we've already done the checking. 1357 DeclGroupPtrTy RangeGroup = 1358 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1359 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1360 if (RangeDecl.isInvalid()) 1361 return StmtError(); 1362 1363 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1364 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1365 RParenLoc); 1366} 1367 1368/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1369StmtResult 1370Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1371 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1372 Expr *Inc, Stmt *LoopVarDecl, 1373 SourceLocation RParenLoc) { 1374 Scope *S = getCurScope(); 1375 1376 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1377 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1378 QualType RangeVarType = RangeVar->getType(); 1379 1380 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1381 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1382 1383 StmtResult BeginEndDecl = BeginEnd; 1384 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1385 1386 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1387 SourceLocation RangeLoc = RangeVar->getLocation(); 1388 1389 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1390 1391 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1392 VK_LValue, ColonLoc); 1393 if (BeginRangeRef.isInvalid()) 1394 return StmtError(); 1395 1396 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1397 VK_LValue, ColonLoc); 1398 if (EndRangeRef.isInvalid()) 1399 return StmtError(); 1400 1401 QualType AutoType = Context.getAutoDeductType(); 1402 Expr *Range = RangeVar->getInit(); 1403 if (!Range) 1404 return StmtError(); 1405 QualType RangeType = Range->getType(); 1406 1407 if (RequireCompleteType(RangeLoc, RangeType, 1408 PDiag(diag::err_for_range_incomplete_type))) 1409 return StmtError(); 1410 1411 // Build auto __begin = begin-expr, __end = end-expr. 1412 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1413 "__begin"); 1414 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1415 "__end"); 1416 1417 // Build begin-expr and end-expr and attach to __begin and __end variables. 1418 ExprResult BeginExpr, EndExpr; 1419 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1420 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1421 // __range + __bound, respectively, where __bound is the array bound. If 1422 // _RangeT is an array of unknown size or an array of incomplete type, 1423 // the program is ill-formed; 1424 1425 // begin-expr is __range. 1426 BeginExpr = BeginRangeRef; 1427 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1428 diag::err_for_range_iter_deduction_failure)) { 1429 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1430 return StmtError(); 1431 } 1432 1433 // Find the array bound. 1434 ExprResult BoundExpr; 1435 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1436 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1437 Context.getPointerDiffType(), 1438 RangeLoc)); 1439 else if (const VariableArrayType *VAT = 1440 dyn_cast<VariableArrayType>(UnqAT)) 1441 BoundExpr = VAT->getSizeExpr(); 1442 else { 1443 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1444 // UnqAT is not incomplete and Range is not type-dependent. 1445 llvm_unreachable("Unexpected array type in for-range"); 1446 } 1447 1448 // end-expr is __range + __bound. 1449 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1450 BoundExpr.get()); 1451 if (EndExpr.isInvalid()) 1452 return StmtError(); 1453 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1454 diag::err_for_range_iter_deduction_failure)) { 1455 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1456 return StmtError(); 1457 } 1458 } else { 1459 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1460 ColonLoc); 1461 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1462 ColonLoc); 1463 1464 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1465 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1466 1467 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1468 // - if _RangeT is a class type, the unqualified-ids begin and end are 1469 // looked up in the scope of class _RangeT as if by class member access 1470 // lookup (3.4.5), and if either (or both) finds at least one 1471 // declaration, begin-expr and end-expr are __range.begin() and 1472 // __range.end(), respectively; 1473 LookupQualifiedName(BeginMemberLookup, D); 1474 LookupQualifiedName(EndMemberLookup, D); 1475 1476 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1477 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1478 << RangeType << BeginMemberLookup.empty(); 1479 return StmtError(); 1480 } 1481 } else { 1482 // - otherwise, begin-expr and end-expr are begin(__range) and 1483 // end(__range), respectively, where begin and end are looked up with 1484 // argument-dependent lookup (3.4.2). For the purposes of this name 1485 // lookup, namespace std is an associated namespace. 1486 } 1487 1488 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1489 BEF_begin, BeginNameInfo, 1490 BeginMemberLookup, 1491 BeginRangeRef.get()); 1492 if (BeginExpr.isInvalid()) 1493 return StmtError(); 1494 1495 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1496 BEF_end, EndNameInfo, 1497 EndMemberLookup, EndRangeRef.get()); 1498 if (EndExpr.isInvalid()) 1499 return StmtError(); 1500 } 1501 1502 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1503 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1504 if (!Context.hasSameType(BeginType, EndType)) { 1505 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1506 << BeginType << EndType; 1507 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1508 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1509 } 1510 1511 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1512 // Claim the type doesn't contain auto: we've already done the checking. 1513 DeclGroupPtrTy BeginEndGroup = 1514 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1515 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1516 1517 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1518 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1519 VK_LValue, ColonLoc); 1520 if (BeginRef.isInvalid()) 1521 return StmtError(); 1522 1523 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1524 VK_LValue, ColonLoc); 1525 if (EndRef.isInvalid()) 1526 return StmtError(); 1527 1528 // Build and check __begin != __end expression. 1529 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1530 BeginRef.get(), EndRef.get()); 1531 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1532 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1533 if (NotEqExpr.isInvalid()) { 1534 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1535 if (!Context.hasSameType(BeginType, EndType)) 1536 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1537 return StmtError(); 1538 } 1539 1540 // Build and check ++__begin expression. 1541 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1542 VK_LValue, ColonLoc); 1543 if (BeginRef.isInvalid()) 1544 return StmtError(); 1545 1546 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1547 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1548 if (IncrExpr.isInvalid()) { 1549 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1550 return StmtError(); 1551 } 1552 1553 // Build and check *__begin expression. 1554 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1555 VK_LValue, ColonLoc); 1556 if (BeginRef.isInvalid()) 1557 return StmtError(); 1558 1559 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1560 if (DerefExpr.isInvalid()) { 1561 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1562 return StmtError(); 1563 } 1564 1565 // Attach *__begin as initializer for VD. 1566 if (!LoopVar->isInvalidDecl()) { 1567 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1568 /*TypeMayContainAuto=*/true); 1569 if (LoopVar->isInvalidDecl()) 1570 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1571 } 1572 } else { 1573 // The range is implicitly used as a placeholder when it is dependent. 1574 RangeVar->setUsed(); 1575 } 1576 1577 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1578 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1579 NotEqExpr.take(), IncrExpr.take(), 1580 LoopVarDS, /*Body=*/0, ForLoc, 1581 ColonLoc, RParenLoc)); 1582} 1583 1584/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1585/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1586/// body cannot be performed until after the type of the range variable is 1587/// determined. 1588StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1589 if (!S || !B) 1590 return StmtError(); 1591 1592 cast<CXXForRangeStmt>(S)->setBody(B); 1593 return S; 1594} 1595 1596StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1597 SourceLocation LabelLoc, 1598 LabelDecl *TheDecl) { 1599 getCurFunction()->setHasBranchIntoScope(); 1600 TheDecl->setUsed(); 1601 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1602} 1603 1604StmtResult 1605Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1606 Expr *E) { 1607 // Convert operand to void* 1608 if (!E->isTypeDependent()) { 1609 QualType ETy = E->getType(); 1610 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1611 ExprResult ExprRes = Owned(E); 1612 AssignConvertType ConvTy = 1613 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1614 if (ExprRes.isInvalid()) 1615 return StmtError(); 1616 E = ExprRes.take(); 1617 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1618 return StmtError(); 1619 } 1620 1621 getCurFunction()->setHasIndirectGoto(); 1622 1623 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1624} 1625 1626StmtResult 1627Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1628 Scope *S = CurScope->getContinueParent(); 1629 if (!S) { 1630 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1631 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1632 } 1633 1634 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1635} 1636 1637StmtResult 1638Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1639 Scope *S = CurScope->getBreakParent(); 1640 if (!S) { 1641 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1642 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1643 } 1644 1645 return Owned(new (Context) BreakStmt(BreakLoc)); 1646} 1647 1648/// \brief Determine whether the given expression is a candidate for 1649/// copy elision in either a return statement or a throw expression. 1650/// 1651/// \param ReturnType If we're determining the copy elision candidate for 1652/// a return statement, this is the return type of the function. If we're 1653/// determining the copy elision candidate for a throw expression, this will 1654/// be a NULL type. 1655/// 1656/// \param E The expression being returned from the function or block, or 1657/// being thrown. 1658/// 1659/// \param AllowFunctionParameter Whether we allow function parameters to 1660/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1661/// we re-use this logic to determine whether we should try to move as part of 1662/// a return or throw (which does allow function parameters). 1663/// 1664/// \returns The NRVO candidate variable, if the return statement may use the 1665/// NRVO, or NULL if there is no such candidate. 1666const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1667 Expr *E, 1668 bool AllowFunctionParameter) { 1669 QualType ExprType = E->getType(); 1670 // - in a return statement in a function with ... 1671 // ... a class return type ... 1672 if (!ReturnType.isNull()) { 1673 if (!ReturnType->isRecordType()) 1674 return 0; 1675 // ... the same cv-unqualified type as the function return type ... 1676 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1677 return 0; 1678 } 1679 1680 // ... the expression is the name of a non-volatile automatic object 1681 // (other than a function or catch-clause parameter)) ... 1682 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1683 if (!DR) 1684 return 0; 1685 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1686 if (!VD) 1687 return 0; 1688 1689 // ...object (other than a function or catch-clause parameter)... 1690 if (VD->getKind() != Decl::Var && 1691 !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) 1692 return 0; 1693 if (VD->isExceptionVariable()) return 0; 1694 1695 // ...automatic... 1696 if (!VD->hasLocalStorage()) return 0; 1697 1698 // ...non-volatile... 1699 if (VD->getType().isVolatileQualified()) return 0; 1700 if (VD->getType()->isReferenceType()) return 0; 1701 1702 // __block variables can't be allocated in a way that permits NRVO. 1703 if (VD->hasAttr<BlocksAttr>()) return 0; 1704 1705 // Variables with higher required alignment than their type's ABI 1706 // alignment cannot use NRVO. 1707 if (VD->hasAttr<AlignedAttr>() && 1708 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) 1709 return 0; 1710 1711 return VD; 1712} 1713 1714/// \brief Perform the initialization of a potentially-movable value, which 1715/// is the result of return value. 1716/// 1717/// This routine implements C++0x [class.copy]p33, which attempts to treat 1718/// returned lvalues as rvalues in certain cases (to prefer move construction), 1719/// then falls back to treating them as lvalues if that failed. 1720ExprResult 1721Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1722 const VarDecl *NRVOCandidate, 1723 QualType ResultType, 1724 Expr *Value, 1725 bool AllowNRVO) { 1726 // C++0x [class.copy]p33: 1727 // When the criteria for elision of a copy operation are met or would 1728 // be met save for the fact that the source object is a function 1729 // parameter, and the object to be copied is designated by an lvalue, 1730 // overload resolution to select the constructor for the copy is first 1731 // performed as if the object were designated by an rvalue. 1732 ExprResult Res = ExprError(); 1733 if (AllowNRVO && 1734 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 1735 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1736 Value->getType(), CK_LValueToRValue, 1737 Value, VK_XValue); 1738 1739 Expr *InitExpr = &AsRvalue; 1740 InitializationKind Kind 1741 = InitializationKind::CreateCopy(Value->getLocStart(), 1742 Value->getLocStart()); 1743 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1744 1745 // [...] If overload resolution fails, or if the type of the first 1746 // parameter of the selected constructor is not an rvalue reference 1747 // to the object's type (possibly cv-qualified), overload resolution 1748 // is performed again, considering the object as an lvalue. 1749 if (Seq) { 1750 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1751 StepEnd = Seq.step_end(); 1752 Step != StepEnd; ++Step) { 1753 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 1754 continue; 1755 1756 CXXConstructorDecl *Constructor 1757 = cast<CXXConstructorDecl>(Step->Function.Function); 1758 1759 const RValueReferenceType *RRefType 1760 = Constructor->getParamDecl(0)->getType() 1761 ->getAs<RValueReferenceType>(); 1762 1763 // If we don't meet the criteria, break out now. 1764 if (!RRefType || 1765 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1766 Context.getTypeDeclType(Constructor->getParent()))) 1767 break; 1768 1769 // Promote "AsRvalue" to the heap, since we now need this 1770 // expression node to persist. 1771 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1772 CK_LValueToRValue, Value, 0, 1773 VK_XValue); 1774 1775 // Complete type-checking the initialization of the return type 1776 // using the constructor we found. 1777 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1778 } 1779 } 1780 } 1781 1782 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1783 // above, or overload resolution failed. Either way, we need to try 1784 // (again) now with the return value expression as written. 1785 if (Res.isInvalid()) 1786 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1787 1788 return Res; 1789} 1790 1791/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1792/// 1793StmtResult 1794Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1795 // If this is the first return we've seen in the block, infer the type of 1796 // the block from it. 1797 BlockScopeInfo *CurBlock = getCurBlock(); 1798 if (CurBlock->TheDecl->blockMissingReturnType()) { 1799 QualType BlockReturnT; 1800 if (RetValExp) { 1801 // Don't call UsualUnaryConversions(), since we don't want to do 1802 // integer promotions here. 1803 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 1804 if (Result.isInvalid()) 1805 return StmtError(); 1806 RetValExp = Result.take(); 1807 1808 if (!RetValExp->isTypeDependent()) { 1809 BlockReturnT = RetValExp->getType(); 1810 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1811 // We have to remove a 'const' added to copied-in variable which was 1812 // part of the implementation spec. and not the actual qualifier for 1813 // the variable. 1814 if (CDRE->isConstQualAdded()) 1815 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1816 } 1817 } else 1818 BlockReturnT = Context.DependentTy; 1819 } else 1820 BlockReturnT = Context.VoidTy; 1821 if (!CurBlock->ReturnType.isNull() && !CurBlock->ReturnType->isDependentType() 1822 && !BlockReturnT->isDependentType() 1823 // when block's return type is not specified, all return types 1824 // must strictly match. 1825 && !Context.hasSameType(BlockReturnT, CurBlock->ReturnType)) { 1826 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) 1827 << BlockReturnT << CurBlock->ReturnType; 1828 return StmtError(); 1829 } 1830 CurBlock->ReturnType = BlockReturnT; 1831 } 1832 QualType FnRetType = CurBlock->ReturnType; 1833 1834 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1835 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr); 1836 return StmtError(); 1837 } 1838 1839 // Otherwise, verify that this result type matches the previous one. We are 1840 // pickier with blocks than for normal functions because we don't have GCC 1841 // compatibility to worry about here. 1842 const VarDecl *NRVOCandidate = 0; 1843 if (FnRetType->isDependentType()) { 1844 // Delay processing for now. TODO: there are lots of dependent 1845 // types we can conclusively prove aren't void. 1846 } else if (FnRetType->isVoidType()) { 1847 if (RetValExp && 1848 !(getLangOptions().CPlusPlus && 1849 (RetValExp->isTypeDependent() || 1850 RetValExp->getType()->isVoidType()))) { 1851 Diag(ReturnLoc, diag::err_return_block_has_expr); 1852 RetValExp = 0; 1853 } 1854 } else if (!RetValExp) { 1855 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1856 } else if (!RetValExp->isTypeDependent()) { 1857 // we have a non-void block with an expression, continue checking 1858 1859 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1860 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1861 // function return. 1862 1863 // In C++ the return statement is handled via a copy initialization. 1864 // the C version of which boils down to CheckSingleAssignmentConstraints. 1865 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1866 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1867 FnRetType, 1868 NRVOCandidate != 0); 1869 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1870 FnRetType, RetValExp); 1871 if (Res.isInvalid()) { 1872 // FIXME: Cleanup temporaries here, anyway? 1873 return StmtError(); 1874 } 1875 RetValExp = Res.take(); 1876 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1877 } 1878 1879 if (RetValExp) { 1880 CheckImplicitConversions(RetValExp, ReturnLoc); 1881 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1882 } 1883 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 1884 NRVOCandidate); 1885 1886 // If we need to check for the named return value optimization, save the 1887 // return statement in our scope for later processing. 1888 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1889 !CurContext->isDependentContext()) 1890 FunctionScopes.back()->Returns.push_back(Result); 1891 1892 return Owned(Result); 1893} 1894 1895StmtResult 1896Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1897 // Check for unexpanded parameter packs. 1898 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 1899 return StmtError(); 1900 1901 if (getCurBlock()) 1902 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1903 1904 QualType FnRetType; 1905 QualType DeclaredRetType; 1906 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1907 FnRetType = FD->getResultType(); 1908 DeclaredRetType = FnRetType; 1909 if (FD->hasAttr<NoReturnAttr>() || 1910 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1911 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1912 << FD->getDeclName(); 1913 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 1914 DeclaredRetType = MD->getResultType(); 1915 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 1916 // In the implementation of a method with a related return type, the 1917 // type used to type-check the validity of return statements within the 1918 // method body is a pointer to the type of the class being implemented. 1919 FnRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 1920 FnRetType = Context.getObjCObjectPointerType(FnRetType); 1921 } else { 1922 FnRetType = DeclaredRetType; 1923 } 1924 } else // If we don't have a function/method context, bail. 1925 return StmtError(); 1926 1927 ReturnStmt *Result = 0; 1928 if (FnRetType->isVoidType()) { 1929 if (RetValExp) { 1930 if (!RetValExp->isTypeDependent()) { 1931 // C99 6.8.6.4p1 (ext_ since GCC warns) 1932 unsigned D = diag::ext_return_has_expr; 1933 if (RetValExp->getType()->isVoidType()) 1934 D = diag::ext_return_has_void_expr; 1935 else { 1936 ExprResult Result = Owned(RetValExp); 1937 Result = IgnoredValueConversions(Result.take()); 1938 if (Result.isInvalid()) 1939 return StmtError(); 1940 RetValExp = Result.take(); 1941 RetValExp = ImpCastExprToType(RetValExp, 1942 Context.VoidTy, CK_ToVoid).take(); 1943 } 1944 1945 // return (some void expression); is legal in C++. 1946 if (D != diag::ext_return_has_void_expr || 1947 !getLangOptions().CPlusPlus) { 1948 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1949 1950 int FunctionKind = 0; 1951 if (isa<ObjCMethodDecl>(CurDecl)) 1952 FunctionKind = 1; 1953 else if (isa<CXXConstructorDecl>(CurDecl)) 1954 FunctionKind = 2; 1955 else if (isa<CXXDestructorDecl>(CurDecl)) 1956 FunctionKind = 3; 1957 1958 Diag(ReturnLoc, D) 1959 << CurDecl->getDeclName() << FunctionKind 1960 << RetValExp->getSourceRange(); 1961 } 1962 } 1963 1964 CheckImplicitConversions(RetValExp, ReturnLoc); 1965 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1966 } 1967 1968 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1969 } else if (!RetValExp && !FnRetType->isDependentType()) { 1970 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1971 // C99 6.8.6.4p1 (ext_ since GCC warns) 1972 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1973 1974 if (FunctionDecl *FD = getCurFunctionDecl()) 1975 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1976 else 1977 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1978 Result = new (Context) ReturnStmt(ReturnLoc); 1979 } else { 1980 const VarDecl *NRVOCandidate = 0; 1981 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1982 // we have a non-void function with an expression, continue checking 1983 1984 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1985 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1986 // function return. 1987 1988 // In C++ the return statement is handled via a copy initialization, 1989 // the C version of which boils down to CheckSingleAssignmentConstraints. 1990 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1991 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1992 FnRetType, 1993 NRVOCandidate != 0); 1994 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1995 FnRetType, RetValExp); 1996 if (Res.isInvalid()) { 1997 // FIXME: Cleanup temporaries here, anyway? 1998 return StmtError(); 1999 } 2000 2001 RetValExp = Res.takeAs<Expr>(); 2002 if (RetValExp) 2003 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 2004 } 2005 2006 if (RetValExp) { 2007 // If we type-checked an Objective-C method's return type based 2008 // on a related return type, we may need to adjust the return 2009 // type again. Do so now. 2010 if (DeclaredRetType != FnRetType) { 2011 ExprResult result = PerformImplicitConversion(RetValExp, 2012 DeclaredRetType, 2013 AA_Returning); 2014 if (result.isInvalid()) return StmtError(); 2015 RetValExp = result.take(); 2016 } 2017 2018 CheckImplicitConversions(RetValExp, ReturnLoc); 2019 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 2020 } 2021 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 2022 } 2023 2024 // If we need to check for the named return value optimization, save the 2025 // return statement in our scope for later processing. 2026 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 2027 !CurContext->isDependentContext()) 2028 FunctionScopes.back()->Returns.push_back(Result); 2029 2030 return Owned(Result); 2031} 2032 2033/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 2034/// ignore "noop" casts in places where an lvalue is required by an inline asm. 2035/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 2036/// provide a strong guidance to not use it. 2037/// 2038/// This method checks to see if the argument is an acceptable l-value and 2039/// returns false if it is a case we can handle. 2040static bool CheckAsmLValue(const Expr *E, Sema &S) { 2041 // Type dependent expressions will be checked during instantiation. 2042 if (E->isTypeDependent()) 2043 return false; 2044 2045 if (E->isLValue()) 2046 return false; // Cool, this is an lvalue. 2047 2048 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 2049 // are supposed to allow. 2050 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 2051 if (E != E2 && E2->isLValue()) { 2052 if (!S.getLangOptions().HeinousExtensions) 2053 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 2054 << E->getSourceRange(); 2055 else 2056 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 2057 << E->getSourceRange(); 2058 // Accept, even if we emitted an error diagnostic. 2059 return false; 2060 } 2061 2062 // None of the above, just randomly invalid non-lvalue. 2063 return true; 2064} 2065 2066/// isOperandMentioned - Return true if the specified operand # is mentioned 2067/// anywhere in the decomposed asm string. 2068static bool isOperandMentioned(unsigned OpNo, 2069 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2070 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2071 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2072 if (!Piece.isOperand()) continue; 2073 2074 // If this is a reference to the input and if the input was the smaller 2075 // one, then we have to reject this asm. 2076 if (Piece.getOperandNo() == OpNo) 2077 return true; 2078 } 2079 2080 return false; 2081} 2082 2083StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2084 bool IsVolatile, unsigned NumOutputs, 2085 unsigned NumInputs, IdentifierInfo **Names, 2086 MultiExprArg constraints, MultiExprArg exprs, 2087 Expr *asmString, MultiExprArg clobbers, 2088 SourceLocation RParenLoc, bool MSAsm) { 2089 unsigned NumClobbers = clobbers.size(); 2090 StringLiteral **Constraints = 2091 reinterpret_cast<StringLiteral**>(constraints.get()); 2092 Expr **Exprs = exprs.get(); 2093 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2094 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2095 2096 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2097 2098 // The parser verifies that there is a string literal here. 2099 if (!AsmString->isAscii()) 2100 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2101 << AsmString->getSourceRange()); 2102 2103 for (unsigned i = 0; i != NumOutputs; i++) { 2104 StringLiteral *Literal = Constraints[i]; 2105 if (!Literal->isAscii()) 2106 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2107 << Literal->getSourceRange()); 2108 2109 StringRef OutputName; 2110 if (Names[i]) 2111 OutputName = Names[i]->getName(); 2112 2113 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2114 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2115 return StmtError(Diag(Literal->getLocStart(), 2116 diag::err_asm_invalid_output_constraint) 2117 << Info.getConstraintStr()); 2118 2119 // Check that the output exprs are valid lvalues. 2120 Expr *OutputExpr = Exprs[i]; 2121 if (CheckAsmLValue(OutputExpr, *this)) { 2122 return StmtError(Diag(OutputExpr->getLocStart(), 2123 diag::err_asm_invalid_lvalue_in_output) 2124 << OutputExpr->getSourceRange()); 2125 } 2126 2127 OutputConstraintInfos.push_back(Info); 2128 } 2129 2130 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2131 2132 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2133 StringLiteral *Literal = Constraints[i]; 2134 if (!Literal->isAscii()) 2135 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2136 << Literal->getSourceRange()); 2137 2138 StringRef InputName; 2139 if (Names[i]) 2140 InputName = Names[i]->getName(); 2141 2142 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2143 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2144 NumOutputs, Info)) { 2145 return StmtError(Diag(Literal->getLocStart(), 2146 diag::err_asm_invalid_input_constraint) 2147 << Info.getConstraintStr()); 2148 } 2149 2150 Expr *InputExpr = Exprs[i]; 2151 2152 // Only allow void types for memory constraints. 2153 if (Info.allowsMemory() && !Info.allowsRegister()) { 2154 if (CheckAsmLValue(InputExpr, *this)) 2155 return StmtError(Diag(InputExpr->getLocStart(), 2156 diag::err_asm_invalid_lvalue_in_input) 2157 << Info.getConstraintStr() 2158 << InputExpr->getSourceRange()); 2159 } 2160 2161 if (Info.allowsRegister()) { 2162 if (InputExpr->getType()->isVoidType()) { 2163 return StmtError(Diag(InputExpr->getLocStart(), 2164 diag::err_asm_invalid_type_in_input) 2165 << InputExpr->getType() << Info.getConstraintStr() 2166 << InputExpr->getSourceRange()); 2167 } 2168 } 2169 2170 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2171 if (Result.isInvalid()) 2172 return StmtError(); 2173 2174 Exprs[i] = Result.take(); 2175 InputConstraintInfos.push_back(Info); 2176 } 2177 2178 // Check that the clobbers are valid. 2179 for (unsigned i = 0; i != NumClobbers; i++) { 2180 StringLiteral *Literal = Clobbers[i]; 2181 if (!Literal->isAscii()) 2182 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2183 << Literal->getSourceRange()); 2184 2185 StringRef Clobber = Literal->getString(); 2186 2187 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2188 return StmtError(Diag(Literal->getLocStart(), 2189 diag::err_asm_unknown_register_name) << Clobber); 2190 } 2191 2192 AsmStmt *NS = 2193 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2194 NumOutputs, NumInputs, Names, Constraints, Exprs, 2195 AsmString, NumClobbers, Clobbers, RParenLoc); 2196 // Validate the asm string, ensuring it makes sense given the operands we 2197 // have. 2198 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2199 unsigned DiagOffs; 2200 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2201 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2202 << AsmString->getSourceRange(); 2203 return StmtError(); 2204 } 2205 2206 // Validate tied input operands for type mismatches. 2207 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2208 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2209 2210 // If this is a tied constraint, verify that the output and input have 2211 // either exactly the same type, or that they are int/ptr operands with the 2212 // same size (int/long, int*/long, are ok etc). 2213 if (!Info.hasTiedOperand()) continue; 2214 2215 unsigned TiedTo = Info.getTiedOperand(); 2216 unsigned InputOpNo = i+NumOutputs; 2217 Expr *OutputExpr = Exprs[TiedTo]; 2218 Expr *InputExpr = Exprs[InputOpNo]; 2219 2220 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2221 continue; 2222 2223 QualType InTy = InputExpr->getType(); 2224 QualType OutTy = OutputExpr->getType(); 2225 if (Context.hasSameType(InTy, OutTy)) 2226 continue; // All types can be tied to themselves. 2227 2228 // Decide if the input and output are in the same domain (integer/ptr or 2229 // floating point. 2230 enum AsmDomain { 2231 AD_Int, AD_FP, AD_Other 2232 } InputDomain, OutputDomain; 2233 2234 if (InTy->isIntegerType() || InTy->isPointerType()) 2235 InputDomain = AD_Int; 2236 else if (InTy->isRealFloatingType()) 2237 InputDomain = AD_FP; 2238 else 2239 InputDomain = AD_Other; 2240 2241 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2242 OutputDomain = AD_Int; 2243 else if (OutTy->isRealFloatingType()) 2244 OutputDomain = AD_FP; 2245 else 2246 OutputDomain = AD_Other; 2247 2248 // They are ok if they are the same size and in the same domain. This 2249 // allows tying things like: 2250 // void* to int* 2251 // void* to int if they are the same size. 2252 // double to long double if they are the same size. 2253 // 2254 uint64_t OutSize = Context.getTypeSize(OutTy); 2255 uint64_t InSize = Context.getTypeSize(InTy); 2256 if (OutSize == InSize && InputDomain == OutputDomain && 2257 InputDomain != AD_Other) 2258 continue; 2259 2260 // If the smaller input/output operand is not mentioned in the asm string, 2261 // then we can promote the smaller one to a larger input and the asm string 2262 // won't notice. 2263 bool SmallerValueMentioned = false; 2264 2265 // If this is a reference to the input and if the input was the smaller 2266 // one, then we have to reject this asm. 2267 if (isOperandMentioned(InputOpNo, Pieces)) { 2268 // This is a use in the asm string of the smaller operand. Since we 2269 // codegen this by promoting to a wider value, the asm will get printed 2270 // "wrong". 2271 SmallerValueMentioned |= InSize < OutSize; 2272 } 2273 if (isOperandMentioned(TiedTo, Pieces)) { 2274 // If this is a reference to the output, and if the output is the larger 2275 // value, then it's ok because we'll promote the input to the larger type. 2276 SmallerValueMentioned |= OutSize < InSize; 2277 } 2278 2279 // If the smaller value wasn't mentioned in the asm string, and if the 2280 // output was a register, just extend the shorter one to the size of the 2281 // larger one. 2282 if (!SmallerValueMentioned && InputDomain != AD_Other && 2283 OutputConstraintInfos[TiedTo].allowsRegister()) 2284 continue; 2285 2286 // Either both of the operands were mentioned or the smaller one was 2287 // mentioned. One more special case that we'll allow: if the tied input is 2288 // integer, unmentioned, and is a constant, then we'll allow truncating it 2289 // down to the size of the destination. 2290 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2291 !isOperandMentioned(InputOpNo, Pieces) && 2292 InputExpr->isEvaluatable(Context)) { 2293 CastKind castKind = 2294 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2295 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2296 Exprs[InputOpNo] = InputExpr; 2297 NS->setInputExpr(i, InputExpr); 2298 continue; 2299 } 2300 2301 Diag(InputExpr->getLocStart(), 2302 diag::err_asm_tying_incompatible_types) 2303 << InTy << OutTy << OutputExpr->getSourceRange() 2304 << InputExpr->getSourceRange(); 2305 return StmtError(); 2306 } 2307 2308 return Owned(NS); 2309} 2310 2311StmtResult 2312Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2313 SourceLocation RParen, Decl *Parm, 2314 Stmt *Body) { 2315 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2316 if (Var && Var->isInvalidDecl()) 2317 return StmtError(); 2318 2319 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2320} 2321 2322StmtResult 2323Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2324 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2325} 2326 2327StmtResult 2328Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2329 MultiStmtArg CatchStmts, Stmt *Finally) { 2330 if (!getLangOptions().ObjCExceptions) 2331 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2332 2333 getCurFunction()->setHasBranchProtectedScope(); 2334 unsigned NumCatchStmts = CatchStmts.size(); 2335 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2336 CatchStmts.release(), 2337 NumCatchStmts, 2338 Finally)); 2339} 2340 2341StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 2342 Expr *Throw) { 2343 if (Throw) { 2344 Throw = MaybeCreateExprWithCleanups(Throw); 2345 ExprResult Result = DefaultLvalueConversion(Throw); 2346 if (Result.isInvalid()) 2347 return StmtError(); 2348 2349 Throw = Result.take(); 2350 QualType ThrowType = Throw->getType(); 2351 // Make sure the expression type is an ObjC pointer or "void *". 2352 if (!ThrowType->isDependentType() && 2353 !ThrowType->isObjCObjectPointerType()) { 2354 const PointerType *PT = ThrowType->getAs<PointerType>(); 2355 if (!PT || !PT->getPointeeType()->isVoidType()) 2356 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2357 << Throw->getType() << Throw->getSourceRange()); 2358 } 2359 } 2360 2361 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2362} 2363 2364StmtResult 2365Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2366 Scope *CurScope) { 2367 if (!getLangOptions().ObjCExceptions) 2368 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2369 2370 if (!Throw) { 2371 // @throw without an expression designates a rethrow (which much occur 2372 // in the context of an @catch clause). 2373 Scope *AtCatchParent = CurScope; 2374 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2375 AtCatchParent = AtCatchParent->getParent(); 2376 if (!AtCatchParent) 2377 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2378 } 2379 2380 return BuildObjCAtThrowStmt(AtLoc, Throw); 2381} 2382 2383ExprResult 2384Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 2385 ExprResult result = DefaultLvalueConversion(operand); 2386 if (result.isInvalid()) 2387 return ExprError(); 2388 operand = result.take(); 2389 2390 // Make sure the expression type is an ObjC pointer or "void *". 2391 QualType type = operand->getType(); 2392 if (!type->isDependentType() && 2393 !type->isObjCObjectPointerType()) { 2394 const PointerType *pointerType = type->getAs<PointerType>(); 2395 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 2396 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 2397 << type << operand->getSourceRange(); 2398 } 2399 2400 // The operand to @synchronized is a full-expression. 2401 return MaybeCreateExprWithCleanups(operand); 2402} 2403 2404StmtResult 2405Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2406 Stmt *SyncBody) { 2407 // We can't jump into or indirect-jump out of a @synchronized block. 2408 getCurFunction()->setHasBranchProtectedScope(); 2409 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2410} 2411 2412/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2413/// and creates a proper catch handler from them. 2414StmtResult 2415Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2416 Stmt *HandlerBlock) { 2417 // There's nothing to test that ActOnExceptionDecl didn't already test. 2418 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2419 cast_or_null<VarDecl>(ExDecl), 2420 HandlerBlock)); 2421} 2422 2423StmtResult 2424Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2425 getCurFunction()->setHasBranchProtectedScope(); 2426 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2427} 2428 2429namespace { 2430 2431class TypeWithHandler { 2432 QualType t; 2433 CXXCatchStmt *stmt; 2434public: 2435 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2436 : t(type), stmt(statement) {} 2437 2438 // An arbitrary order is fine as long as it places identical 2439 // types next to each other. 2440 bool operator<(const TypeWithHandler &y) const { 2441 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2442 return true; 2443 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2444 return false; 2445 else 2446 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2447 } 2448 2449 bool operator==(const TypeWithHandler& other) const { 2450 return t == other.t; 2451 } 2452 2453 CXXCatchStmt *getCatchStmt() const { return stmt; } 2454 SourceLocation getTypeSpecStartLoc() const { 2455 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2456 } 2457}; 2458 2459} 2460 2461/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2462/// handlers and creates a try statement from them. 2463StmtResult 2464Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2465 MultiStmtArg RawHandlers) { 2466 // Don't report an error if 'try' is used in system headers. 2467 if (!getLangOptions().CXXExceptions && 2468 !getSourceManager().isInSystemHeader(TryLoc)) 2469 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2470 2471 unsigned NumHandlers = RawHandlers.size(); 2472 assert(NumHandlers > 0 && 2473 "The parser shouldn't call this if there are no handlers."); 2474 Stmt **Handlers = RawHandlers.get(); 2475 2476 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2477 2478 for (unsigned i = 0; i < NumHandlers; ++i) { 2479 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2480 if (!Handler->getExceptionDecl()) { 2481 if (i < NumHandlers - 1) 2482 return StmtError(Diag(Handler->getLocStart(), 2483 diag::err_early_catch_all)); 2484 2485 continue; 2486 } 2487 2488 const QualType CaughtType = Handler->getCaughtType(); 2489 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2490 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2491 } 2492 2493 // Detect handlers for the same type as an earlier one. 2494 if (NumHandlers > 1) { 2495 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2496 2497 TypeWithHandler prev = TypesWithHandlers[0]; 2498 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2499 TypeWithHandler curr = TypesWithHandlers[i]; 2500 2501 if (curr == prev) { 2502 Diag(curr.getTypeSpecStartLoc(), 2503 diag::warn_exception_caught_by_earlier_handler) 2504 << curr.getCatchStmt()->getCaughtType().getAsString(); 2505 Diag(prev.getTypeSpecStartLoc(), 2506 diag::note_previous_exception_handler) 2507 << prev.getCatchStmt()->getCaughtType().getAsString(); 2508 } 2509 2510 prev = curr; 2511 } 2512 } 2513 2514 getCurFunction()->setHasBranchProtectedScope(); 2515 2516 // FIXME: We should detect handlers that cannot catch anything because an 2517 // earlier handler catches a superclass. Need to find a method that is not 2518 // quadratic for this. 2519 // Neither of these are explicitly forbidden, but every compiler detects them 2520 // and warns. 2521 2522 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2523 Handlers, NumHandlers)); 2524} 2525 2526StmtResult 2527Sema::ActOnSEHTryBlock(bool IsCXXTry, 2528 SourceLocation TryLoc, 2529 Stmt *TryBlock, 2530 Stmt *Handler) { 2531 assert(TryBlock && Handler); 2532 2533 getCurFunction()->setHasBranchProtectedScope(); 2534 2535 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2536} 2537 2538StmtResult 2539Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2540 Expr *FilterExpr, 2541 Stmt *Block) { 2542 assert(FilterExpr && Block); 2543 2544 if(!FilterExpr->getType()->isIntegerType()) { 2545 return StmtError(Diag(FilterExpr->getExprLoc(), 2546 diag::err_filter_expression_integral) 2547 << FilterExpr->getType()); 2548 } 2549 2550 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2551} 2552 2553StmtResult 2554Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2555 Stmt *Block) { 2556 assert(Block); 2557 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2558} 2559 2560StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 2561 bool IsIfExists, 2562 NestedNameSpecifierLoc QualifierLoc, 2563 DeclarationNameInfo NameInfo, 2564 Stmt *Nested) 2565{ 2566 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 2567 QualifierLoc, NameInfo, 2568 cast<CompoundStmt>(Nested)); 2569} 2570 2571 2572StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 2573 bool IsIfExists, 2574 CXXScopeSpec &SS, 2575 UnqualifiedId &Name, 2576 Stmt *Nested) { 2577 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 2578 SS.getWithLocInContext(Context), 2579 GetNameFromUnqualifiedId(Name), 2580 Nested); 2581} 2582