SemaStmt.cpp revision 649657e7d6c150136cae5ab22e39b9794cff80cc
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements semantic analysis for statements. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Sema/SemaInternal.h" 15#include "clang/Sema/Scope.h" 16#include "clang/Sema/ScopeInfo.h" 17#include "clang/Sema/Initialization.h" 18#include "clang/Sema/Lookup.h" 19#include "clang/AST/APValue.h" 20#include "clang/AST/ASTContext.h" 21#include "clang/AST/CharUnits.h" 22#include "clang/AST/DeclObjC.h" 23#include "clang/AST/ExprCXX.h" 24#include "clang/AST/ExprObjC.h" 25#include "clang/AST/StmtObjC.h" 26#include "clang/AST/StmtCXX.h" 27#include "clang/AST/TypeLoc.h" 28#include "clang/Lex/Preprocessor.h" 29#include "clang/Basic/TargetInfo.h" 30#include "llvm/ADT/ArrayRef.h" 31#include "llvm/ADT/STLExtras.h" 32#include "llvm/ADT/SmallVector.h" 33using namespace clang; 34using namespace sema; 35 36StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 37 Expr *E = expr.get(); 38 if (!E) // FIXME: FullExprArg has no error state? 39 return StmtError(); 40 41 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 42 // void expression for its side effects. Conversion to void allows any 43 // operand, even incomplete types. 44 45 // Same thing in for stmt first clause (when expr) and third clause. 46 return Owned(static_cast<Stmt*>(E)); 47} 48 49 50StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, 51 bool HasLeadingEmptyMacro) { 52 return Owned(new (Context) NullStmt(SemiLoc, HasLeadingEmptyMacro)); 53} 54 55StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 56 SourceLocation EndLoc) { 57 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 58 59 // If we have an invalid decl, just return an error. 60 if (DG.isNull()) return StmtError(); 61 62 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 63} 64 65void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 66 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 67 68 // If we have an invalid decl, just return. 69 if (DG.isNull() || !DG.isSingleDecl()) return; 70 VarDecl *var = cast<VarDecl>(DG.getSingleDecl()); 71 72 // suppress any potential 'unused variable' warning. 73 var->setUsed(); 74 75 // foreach variables are never actually initialized in the way that 76 // the parser came up with. 77 var->setInit(0); 78 79 // In ARC, we don't need to retain the iteration variable of a fast 80 // enumeration loop. Rather than actually trying to catch that 81 // during declaration processing, we remove the consequences here. 82 if (getLangOptions().ObjCAutoRefCount) { 83 QualType type = var->getType(); 84 85 // Only do this if we inferred the lifetime. Inferred lifetime 86 // will show up as a local qualifier because explicit lifetime 87 // should have shown up as an AttributedType instead. 88 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { 89 // Add 'const' and mark the variable as pseudo-strong. 90 var->setType(type.withConst()); 91 var->setARCPseudoStrong(true); 92 } 93 } 94} 95 96/// \brief Diagnose unused '==' and '!=' as likely typos for '=' or '|='. 97/// 98/// Adding a cast to void (or other expression wrappers) will prevent the 99/// warning from firing. 100static bool DiagnoseUnusedComparison(Sema &S, const Expr *E) { 101 SourceLocation Loc; 102 bool IsNotEqual, CanAssign; 103 104 if (const BinaryOperator *Op = dyn_cast<BinaryOperator>(E)) { 105 if (Op->getOpcode() != BO_EQ && Op->getOpcode() != BO_NE) 106 return false; 107 108 Loc = Op->getOperatorLoc(); 109 IsNotEqual = Op->getOpcode() == BO_NE; 110 CanAssign = Op->getLHS()->IgnoreParenImpCasts()->isLValue(); 111 } else if (const CXXOperatorCallExpr *Op = dyn_cast<CXXOperatorCallExpr>(E)) { 112 if (Op->getOperator() != OO_EqualEqual && 113 Op->getOperator() != OO_ExclaimEqual) 114 return false; 115 116 Loc = Op->getOperatorLoc(); 117 IsNotEqual = Op->getOperator() == OO_ExclaimEqual; 118 CanAssign = Op->getArg(0)->IgnoreParenImpCasts()->isLValue(); 119 } else { 120 // Not a typo-prone comparison. 121 return false; 122 } 123 124 // Suppress warnings when the operator, suspicious as it may be, comes from 125 // a macro expansion. 126 if (Loc.isMacroID()) 127 return false; 128 129 S.Diag(Loc, diag::warn_unused_comparison) 130 << (unsigned)IsNotEqual << E->getSourceRange(); 131 132 // If the LHS is a plausible entity to assign to, provide a fixit hint to 133 // correct common typos. 134 if (CanAssign) { 135 if (IsNotEqual) 136 S.Diag(Loc, diag::note_inequality_comparison_to_or_assign) 137 << FixItHint::CreateReplacement(Loc, "|="); 138 else 139 S.Diag(Loc, diag::note_equality_comparison_to_assign) 140 << FixItHint::CreateReplacement(Loc, "="); 141 } 142 143 return true; 144} 145 146void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 147 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 148 return DiagnoseUnusedExprResult(Label->getSubStmt()); 149 150 const Expr *E = dyn_cast_or_null<Expr>(S); 151 if (!E) 152 return; 153 154 SourceLocation Loc; 155 SourceRange R1, R2; 156 if (!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 // C99 6.8.4.2p3: The expression shall be an integer constant. 270 // However, GCC allows any evaluatable integer expression. 271 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 272 VerifyIntegerConstantExpression(LHSVal)) 273 return StmtError(); 274 275 // GCC extension: The expression shall be an integer constant. 276 277 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 278 VerifyIntegerConstantExpression(RHSVal)) { 279 RHSVal = 0; // Recover by just forgetting about it. 280 } 281 282 if (getCurFunction()->SwitchStack.empty()) { 283 Diag(CaseLoc, diag::err_case_not_in_switch); 284 return StmtError(); 285 } 286 287 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 288 ColonLoc); 289 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 290 return Owned(CS); 291} 292 293/// ActOnCaseStmtBody - This installs a statement as the body of a case. 294void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 295 DiagnoseUnusedExprResult(SubStmt); 296 297 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 298 CS->setSubStmt(SubStmt); 299} 300 301StmtResult 302Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 303 Stmt *SubStmt, Scope *CurScope) { 304 DiagnoseUnusedExprResult(SubStmt); 305 306 if (getCurFunction()->SwitchStack.empty()) { 307 Diag(DefaultLoc, diag::err_default_not_in_switch); 308 return Owned(SubStmt); 309 } 310 311 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 312 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 313 return Owned(DS); 314} 315 316StmtResult 317Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 318 SourceLocation ColonLoc, Stmt *SubStmt) { 319 320 // If the label was multiply defined, reject it now. 321 if (TheDecl->getStmt()) { 322 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 323 Diag(TheDecl->getLocation(), diag::note_previous_definition); 324 return Owned(SubStmt); 325 } 326 327 // Otherwise, things are good. Fill in the declaration and return it. 328 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 329 TheDecl->setStmt(LS); 330 if (!TheDecl->isGnuLocal()) 331 TheDecl->setLocation(IdentLoc); 332 return Owned(LS); 333} 334 335StmtResult 336Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 337 Stmt *thenStmt, SourceLocation ElseLoc, 338 Stmt *elseStmt) { 339 ExprResult CondResult(CondVal.release()); 340 341 VarDecl *ConditionVar = 0; 342 if (CondVar) { 343 ConditionVar = cast<VarDecl>(CondVar); 344 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 345 if (CondResult.isInvalid()) 346 return StmtError(); 347 } 348 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 349 if (!ConditionExpr) 350 return StmtError(); 351 352 DiagnoseUnusedExprResult(thenStmt); 353 354 // Warn if the if block has a null body without an else value. 355 // this helps prevent bugs due to typos, such as 356 // if (condition); 357 // do_stuff(); 358 // 359 if (!elseStmt) { 360 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 361 // But do not warn if the body is a macro that expands to nothing, e.g: 362 // 363 // #define CALL(x) 364 // if (condition) 365 // CALL(0); 366 // 367 if (!stmt->hasLeadingEmptyMacro()) 368 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 369 } 370 371 DiagnoseUnusedExprResult(elseStmt); 372 373 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 374 thenStmt, ElseLoc, elseStmt)); 375} 376 377/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 378/// the specified width and sign. If an overflow occurs, detect it and emit 379/// the specified diagnostic. 380void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 381 unsigned NewWidth, bool NewSign, 382 SourceLocation Loc, 383 unsigned DiagID) { 384 // Perform a conversion to the promoted condition type if needed. 385 if (NewWidth > Val.getBitWidth()) { 386 // If this is an extension, just do it. 387 Val = Val.extend(NewWidth); 388 Val.setIsSigned(NewSign); 389 390 // If the input was signed and negative and the output is 391 // unsigned, don't bother to warn: this is implementation-defined 392 // behavior. 393 // FIXME: Introduce a second, default-ignored warning for this case? 394 } else if (NewWidth < Val.getBitWidth()) { 395 // If this is a truncation, check for overflow. 396 llvm::APSInt ConvVal(Val); 397 ConvVal = ConvVal.trunc(NewWidth); 398 ConvVal.setIsSigned(NewSign); 399 ConvVal = ConvVal.extend(Val.getBitWidth()); 400 ConvVal.setIsSigned(Val.isSigned()); 401 if (ConvVal != Val) 402 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 403 404 // Regardless of whether a diagnostic was emitted, really do the 405 // truncation. 406 Val = Val.trunc(NewWidth); 407 Val.setIsSigned(NewSign); 408 } else if (NewSign != Val.isSigned()) { 409 // Convert the sign to match the sign of the condition. This can cause 410 // overflow as well: unsigned(INTMIN) 411 // We don't diagnose this overflow, because it is implementation-defined 412 // behavior. 413 // FIXME: Introduce a second, default-ignored warning for this case? 414 llvm::APSInt OldVal(Val); 415 Val.setIsSigned(NewSign); 416 } 417} 418 419namespace { 420 struct CaseCompareFunctor { 421 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 422 const llvm::APSInt &RHS) { 423 return LHS.first < RHS; 424 } 425 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 426 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 427 return LHS.first < RHS.first; 428 } 429 bool operator()(const llvm::APSInt &LHS, 430 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 431 return LHS < RHS.first; 432 } 433 }; 434} 435 436/// CmpCaseVals - Comparison predicate for sorting case values. 437/// 438static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 439 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 440 if (lhs.first < rhs.first) 441 return true; 442 443 if (lhs.first == rhs.first && 444 lhs.second->getCaseLoc().getRawEncoding() 445 < rhs.second->getCaseLoc().getRawEncoding()) 446 return true; 447 return false; 448} 449 450/// CmpEnumVals - Comparison predicate for sorting enumeration values. 451/// 452static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 453 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 454{ 455 return lhs.first < rhs.first; 456} 457 458/// EqEnumVals - Comparison preficate for uniqing enumeration values. 459/// 460static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 461 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 462{ 463 return lhs.first == rhs.first; 464} 465 466/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 467/// potentially integral-promoted expression @p expr. 468static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) { 469 if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr)) 470 expr = cleanups->getSubExpr(); 471 while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) { 472 if (impcast->getCastKind() != CK_IntegralCast) break; 473 expr = impcast->getSubExpr(); 474 } 475 return expr->getType(); 476} 477 478StmtResult 479Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 480 Decl *CondVar) { 481 ExprResult CondResult; 482 483 VarDecl *ConditionVar = 0; 484 if (CondVar) { 485 ConditionVar = cast<VarDecl>(CondVar); 486 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 487 if (CondResult.isInvalid()) 488 return StmtError(); 489 490 Cond = CondResult.release(); 491 } 492 493 if (!Cond) 494 return StmtError(); 495 496 CondResult = CheckPlaceholderExpr(Cond); 497 if (CondResult.isInvalid()) 498 return StmtError(); 499 500 CondResult 501 = ConvertToIntegralOrEnumerationType(SwitchLoc, CondResult.take(), 502 PDiag(diag::err_typecheck_statement_requires_integer), 503 PDiag(diag::err_switch_incomplete_class_type) 504 << Cond->getSourceRange(), 505 PDiag(diag::err_switch_explicit_conversion), 506 PDiag(diag::note_switch_conversion), 507 PDiag(diag::err_switch_multiple_conversions), 508 PDiag(diag::note_switch_conversion), 509 PDiag(0)); 510 if (CondResult.isInvalid()) return StmtError(); 511 Cond = CondResult.take(); 512 513 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 514 CondResult = UsualUnaryConversions(Cond); 515 if (CondResult.isInvalid()) return StmtError(); 516 Cond = CondResult.take(); 517 518 if (!CondVar) { 519 CheckImplicitConversions(Cond, SwitchLoc); 520 CondResult = MaybeCreateExprWithCleanups(Cond); 521 if (CondResult.isInvalid()) 522 return StmtError(); 523 Cond = CondResult.take(); 524 } 525 526 getCurFunction()->setHasBranchIntoScope(); 527 528 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 529 getCurFunction()->SwitchStack.push_back(SS); 530 return Owned(SS); 531} 532 533static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 534 if (Val.getBitWidth() < BitWidth) 535 Val = Val.extend(BitWidth); 536 else if (Val.getBitWidth() > BitWidth) 537 Val = Val.trunc(BitWidth); 538 Val.setIsSigned(IsSigned); 539} 540 541StmtResult 542Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 543 Stmt *BodyStmt) { 544 SwitchStmt *SS = cast<SwitchStmt>(Switch); 545 assert(SS == getCurFunction()->SwitchStack.back() && 546 "switch stack missing push/pop!"); 547 548 SS->setBody(BodyStmt, SwitchLoc); 549 getCurFunction()->SwitchStack.pop_back(); 550 551 Expr *CondExpr = SS->getCond(); 552 if (!CondExpr) return StmtError(); 553 554 QualType CondType = CondExpr->getType(); 555 556 Expr *CondExprBeforePromotion = CondExpr; 557 QualType CondTypeBeforePromotion = 558 GetTypeBeforeIntegralPromotion(CondExprBeforePromotion); 559 560 // C++ 6.4.2.p2: 561 // Integral promotions are performed (on the switch condition). 562 // 563 // A case value unrepresentable by the original switch condition 564 // type (before the promotion) doesn't make sense, even when it can 565 // be represented by the promoted type. Therefore we need to find 566 // the pre-promotion type of the switch condition. 567 if (!CondExpr->isTypeDependent()) { 568 // We have already converted the expression to an integral or enumeration 569 // type, when we started the switch statement. If we don't have an 570 // appropriate type now, just return an error. 571 if (!CondType->isIntegralOrEnumerationType()) 572 return StmtError(); 573 574 if (CondExpr->isKnownToHaveBooleanValue()) { 575 // switch(bool_expr) {...} is often a programmer error, e.g. 576 // switch(n && mask) { ... } // Doh - should be "n & mask". 577 // One can always use an if statement instead of switch(bool_expr). 578 Diag(SwitchLoc, diag::warn_bool_switch_condition) 579 << CondExpr->getSourceRange(); 580 } 581 } 582 583 // Get the bitwidth of the switched-on value before promotions. We must 584 // convert the integer case values to this width before comparison. 585 bool HasDependentValue 586 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 587 unsigned CondWidth 588 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 589 bool CondIsSigned 590 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 591 592 // Accumulate all of the case values in a vector so that we can sort them 593 // and detect duplicates. This vector contains the APInt for the case after 594 // it has been converted to the condition type. 595 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 596 CaseValsTy CaseVals; 597 598 // Keep track of any GNU case ranges we see. The APSInt is the low value. 599 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 600 CaseRangesTy CaseRanges; 601 602 DefaultStmt *TheDefaultStmt = 0; 603 604 bool CaseListIsErroneous = false; 605 606 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 607 SC = SC->getNextSwitchCase()) { 608 609 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 610 if (TheDefaultStmt) { 611 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 612 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 613 614 // FIXME: Remove the default statement from the switch block so that 615 // we'll return a valid AST. This requires recursing down the AST and 616 // finding it, not something we are set up to do right now. For now, 617 // just lop the entire switch stmt out of the AST. 618 CaseListIsErroneous = true; 619 } 620 TheDefaultStmt = DS; 621 622 } else { 623 CaseStmt *CS = cast<CaseStmt>(SC); 624 625 // We already verified that the expression has a i-c-e value (C99 626 // 6.8.4.2p3) - get that value now. 627 Expr *Lo = CS->getLHS(); 628 629 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 630 HasDependentValue = true; 631 break; 632 } 633 634 llvm::APSInt LoVal = Lo->EvaluateKnownConstInt(Context); 635 636 // Convert the value to the same width/sign as the condition. 637 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 638 Lo->getLocStart(), 639 diag::warn_case_value_overflow); 640 641 // If the LHS is not the same type as the condition, insert an implicit 642 // cast. 643 // FIXME: In C++11, the value is a converted constant expression of the 644 // promoted type of the switch condition. 645 Lo = DefaultLvalueConversion(Lo).take(); 646 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 647 CS->setLHS(Lo); 648 649 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 650 if (CS->getRHS()) { 651 if (CS->getRHS()->isTypeDependent() || 652 CS->getRHS()->isValueDependent()) { 653 HasDependentValue = true; 654 break; 655 } 656 CaseRanges.push_back(std::make_pair(LoVal, CS)); 657 } else 658 CaseVals.push_back(std::make_pair(LoVal, CS)); 659 } 660 } 661 662 if (!HasDependentValue) { 663 // If we don't have a default statement, check whether the 664 // condition is constant. 665 llvm::APSInt ConstantCondValue; 666 bool HasConstantCond = false; 667 bool ShouldCheckConstantCond = false; 668 if (!HasDependentValue && !TheDefaultStmt) { 669 Expr::EvalResult Result; 670 HasConstantCond 671 = CondExprBeforePromotion->EvaluateAsRValue(Result, Context); 672 if (HasConstantCond) { 673 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 674 ConstantCondValue = Result.Val.getInt(); 675 ShouldCheckConstantCond = true; 676 677 assert(ConstantCondValue.getBitWidth() == CondWidth && 678 ConstantCondValue.isSigned() == CondIsSigned); 679 } 680 } 681 682 // Sort all the scalar case values so we can easily detect duplicates. 683 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 684 685 if (!CaseVals.empty()) { 686 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 687 if (ShouldCheckConstantCond && 688 CaseVals[i].first == ConstantCondValue) 689 ShouldCheckConstantCond = false; 690 691 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 692 // If we have a duplicate, report it. 693 Diag(CaseVals[i].second->getLHS()->getLocStart(), 694 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 695 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 696 diag::note_duplicate_case_prev); 697 // FIXME: We really want to remove the bogus case stmt from the 698 // substmt, but we have no way to do this right now. 699 CaseListIsErroneous = true; 700 } 701 } 702 } 703 704 // Detect duplicate case ranges, which usually don't exist at all in 705 // the first place. 706 if (!CaseRanges.empty()) { 707 // Sort all the case ranges by their low value so we can easily detect 708 // overlaps between ranges. 709 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 710 711 // Scan the ranges, computing the high values and removing empty ranges. 712 std::vector<llvm::APSInt> HiVals; 713 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 714 llvm::APSInt &LoVal = CaseRanges[i].first; 715 CaseStmt *CR = CaseRanges[i].second; 716 Expr *Hi = CR->getRHS(); 717 llvm::APSInt HiVal = Hi->EvaluateKnownConstInt(Context); 718 719 // Convert the value to the same width/sign as the condition. 720 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 721 Hi->getLocStart(), 722 diag::warn_case_value_overflow); 723 724 // If the RHS is not the same type as the condition, insert an implicit 725 // cast. 726 // FIXME: In C++11, the value is a converted constant expression of the 727 // promoted type of the switch condition. 728 Hi = DefaultLvalueConversion(Hi).take(); 729 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 730 CR->setRHS(Hi); 731 732 // If the low value is bigger than the high value, the case is empty. 733 if (LoVal > HiVal) { 734 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 735 << SourceRange(CR->getLHS()->getLocStart(), 736 Hi->getLocEnd()); 737 CaseRanges.erase(CaseRanges.begin()+i); 738 --i, --e; 739 continue; 740 } 741 742 if (ShouldCheckConstantCond && 743 LoVal <= ConstantCondValue && 744 ConstantCondValue <= HiVal) 745 ShouldCheckConstantCond = false; 746 747 HiVals.push_back(HiVal); 748 } 749 750 // Rescan the ranges, looking for overlap with singleton values and other 751 // ranges. Since the range list is sorted, we only need to compare case 752 // ranges with their neighbors. 753 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 754 llvm::APSInt &CRLo = CaseRanges[i].first; 755 llvm::APSInt &CRHi = HiVals[i]; 756 CaseStmt *CR = CaseRanges[i].second; 757 758 // Check to see whether the case range overlaps with any 759 // singleton cases. 760 CaseStmt *OverlapStmt = 0; 761 llvm::APSInt OverlapVal(32); 762 763 // Find the smallest value >= the lower bound. If I is in the 764 // case range, then we have overlap. 765 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 766 CaseVals.end(), CRLo, 767 CaseCompareFunctor()); 768 if (I != CaseVals.end() && I->first < CRHi) { 769 OverlapVal = I->first; // Found overlap with scalar. 770 OverlapStmt = I->second; 771 } 772 773 // Find the smallest value bigger than the upper bound. 774 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 775 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 776 OverlapVal = (I-1)->first; // Found overlap with scalar. 777 OverlapStmt = (I-1)->second; 778 } 779 780 // Check to see if this case stmt overlaps with the subsequent 781 // case range. 782 if (i && CRLo <= HiVals[i-1]) { 783 OverlapVal = HiVals[i-1]; // Found overlap with range. 784 OverlapStmt = CaseRanges[i-1].second; 785 } 786 787 if (OverlapStmt) { 788 // If we have a duplicate, report it. 789 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 790 << OverlapVal.toString(10); 791 Diag(OverlapStmt->getLHS()->getLocStart(), 792 diag::note_duplicate_case_prev); 793 // FIXME: We really want to remove the bogus case stmt from the 794 // substmt, but we have no way to do this right now. 795 CaseListIsErroneous = true; 796 } 797 } 798 } 799 800 // Complain if we have a constant condition and we didn't find a match. 801 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 802 // TODO: it would be nice if we printed enums as enums, chars as 803 // chars, etc. 804 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 805 << ConstantCondValue.toString(10) 806 << CondExpr->getSourceRange(); 807 } 808 809 // Check to see if switch is over an Enum and handles all of its 810 // values. We only issue a warning if there is not 'default:', but 811 // we still do the analysis to preserve this information in the AST 812 // (which can be used by flow-based analyes). 813 // 814 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 815 816 // If switch has default case, then ignore it. 817 if (!CaseListIsErroneous && !HasConstantCond && ET) { 818 const EnumDecl *ED = ET->getDecl(); 819 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 820 EnumValsTy; 821 EnumValsTy EnumVals; 822 823 // Gather all enum values, set their type and sort them, 824 // allowing easier comparison with CaseVals. 825 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 826 EDI != ED->enumerator_end(); ++EDI) { 827 llvm::APSInt Val = EDI->getInitVal(); 828 AdjustAPSInt(Val, CondWidth, CondIsSigned); 829 EnumVals.push_back(std::make_pair(Val, *EDI)); 830 } 831 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 832 EnumValsTy::iterator EIend = 833 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 834 835 // See which case values aren't in enum. 836 // TODO: we might want to check whether case values are out of the 837 // enum even if we don't want to check whether all cases are handled. 838 if (!TheDefaultStmt) { 839 EnumValsTy::const_iterator EI = EnumVals.begin(); 840 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 841 CI != CaseVals.end(); CI++) { 842 while (EI != EIend && EI->first < CI->first) 843 EI++; 844 if (EI == EIend || EI->first > CI->first) 845 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 846 << ED->getDeclName(); 847 } 848 // See which of case ranges aren't in enum 849 EI = EnumVals.begin(); 850 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 851 RI != CaseRanges.end() && EI != EIend; RI++) { 852 while (EI != EIend && EI->first < RI->first) 853 EI++; 854 855 if (EI == EIend || EI->first != RI->first) { 856 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 857 << ED->getDeclName(); 858 } 859 860 llvm::APSInt Hi = 861 RI->second->getRHS()->EvaluateKnownConstInt(Context); 862 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 863 while (EI != EIend && EI->first < Hi) 864 EI++; 865 if (EI == EIend || EI->first != Hi) 866 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 867 << ED->getDeclName(); 868 } 869 } 870 871 // Check which enum vals aren't in switch 872 CaseValsTy::const_iterator CI = CaseVals.begin(); 873 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 874 bool hasCasesNotInSwitch = false; 875 876 SmallVector<DeclarationName,8> UnhandledNames; 877 878 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 879 // Drop unneeded case values 880 llvm::APSInt CIVal; 881 while (CI != CaseVals.end() && CI->first < EI->first) 882 CI++; 883 884 if (CI != CaseVals.end() && CI->first == EI->first) 885 continue; 886 887 // Drop unneeded case ranges 888 for (; RI != CaseRanges.end(); RI++) { 889 llvm::APSInt Hi = 890 RI->second->getRHS()->EvaluateKnownConstInt(Context); 891 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 892 if (EI->first <= Hi) 893 break; 894 } 895 896 if (RI == CaseRanges.end() || EI->first < RI->first) { 897 hasCasesNotInSwitch = true; 898 if (!TheDefaultStmt) 899 UnhandledNames.push_back(EI->second->getDeclName()); 900 } 901 } 902 903 // Produce a nice diagnostic if multiple values aren't handled. 904 switch (UnhandledNames.size()) { 905 case 0: break; 906 case 1: 907 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 908 << UnhandledNames[0]; 909 break; 910 case 2: 911 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 912 << UnhandledNames[0] << UnhandledNames[1]; 913 break; 914 case 3: 915 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 916 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 917 break; 918 default: 919 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 920 << (unsigned)UnhandledNames.size() 921 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 922 break; 923 } 924 925 if (!hasCasesNotInSwitch) 926 SS->setAllEnumCasesCovered(); 927 } 928 } 929 930 // FIXME: If the case list was broken is some way, we don't have a good system 931 // to patch it up. Instead, just return the whole substmt as broken. 932 if (CaseListIsErroneous) 933 return StmtError(); 934 935 return Owned(SS); 936} 937 938StmtResult 939Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 940 Decl *CondVar, Stmt *Body) { 941 ExprResult CondResult(Cond.release()); 942 943 VarDecl *ConditionVar = 0; 944 if (CondVar) { 945 ConditionVar = cast<VarDecl>(CondVar); 946 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 947 if (CondResult.isInvalid()) 948 return StmtError(); 949 } 950 Expr *ConditionExpr = CondResult.take(); 951 if (!ConditionExpr) 952 return StmtError(); 953 954 DiagnoseUnusedExprResult(Body); 955 956 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 957 Body, WhileLoc)); 958} 959 960StmtResult 961Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 962 SourceLocation WhileLoc, SourceLocation CondLParen, 963 Expr *Cond, SourceLocation CondRParen) { 964 assert(Cond && "ActOnDoStmt(): missing expression"); 965 966 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 967 if (CondResult.isInvalid() || CondResult.isInvalid()) 968 return StmtError(); 969 Cond = CondResult.take(); 970 971 CheckImplicitConversions(Cond, DoLoc); 972 CondResult = MaybeCreateExprWithCleanups(Cond); 973 if (CondResult.isInvalid()) 974 return StmtError(); 975 Cond = CondResult.take(); 976 977 DiagnoseUnusedExprResult(Body); 978 979 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 980} 981 982StmtResult 983Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 984 Stmt *First, FullExprArg second, Decl *secondVar, 985 FullExprArg third, 986 SourceLocation RParenLoc, Stmt *Body) { 987 if (!getLangOptions().CPlusPlus) { 988 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 989 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 990 // declare identifiers for objects having storage class 'auto' or 991 // 'register'. 992 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 993 DI!=DE; ++DI) { 994 VarDecl *VD = dyn_cast<VarDecl>(*DI); 995 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 996 VD = 0; 997 if (VD == 0) 998 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 999 // FIXME: mark decl erroneous! 1000 } 1001 } 1002 } 1003 1004 ExprResult SecondResult(second.release()); 1005 VarDecl *ConditionVar = 0; 1006 if (secondVar) { 1007 ConditionVar = cast<VarDecl>(secondVar); 1008 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 1009 if (SecondResult.isInvalid()) 1010 return StmtError(); 1011 } 1012 1013 Expr *Third = third.release().takeAs<Expr>(); 1014 1015 DiagnoseUnusedExprResult(First); 1016 DiagnoseUnusedExprResult(Third); 1017 DiagnoseUnusedExprResult(Body); 1018 1019 return Owned(new (Context) ForStmt(Context, First, 1020 SecondResult.take(), ConditionVar, 1021 Third, Body, ForLoc, LParenLoc, 1022 RParenLoc)); 1023} 1024 1025/// In an Objective C collection iteration statement: 1026/// for (x in y) 1027/// x can be an arbitrary l-value expression. Bind it up as a 1028/// full-expression. 1029StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 1030 CheckImplicitConversions(E); 1031 ExprResult Result = MaybeCreateExprWithCleanups(E); 1032 if (Result.isInvalid()) return StmtError(); 1033 return Owned(static_cast<Stmt*>(Result.get())); 1034} 1035 1036ExprResult 1037Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 1038 assert(collection); 1039 1040 // Bail out early if we've got a type-dependent expression. 1041 if (collection->isTypeDependent()) return Owned(collection); 1042 1043 // Perform normal l-value conversion. 1044 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 1045 if (result.isInvalid()) 1046 return ExprError(); 1047 collection = result.take(); 1048 1049 // The operand needs to have object-pointer type. 1050 // TODO: should we do a contextual conversion? 1051 const ObjCObjectPointerType *pointerType = 1052 collection->getType()->getAs<ObjCObjectPointerType>(); 1053 if (!pointerType) 1054 return Diag(forLoc, diag::err_collection_expr_type) 1055 << collection->getType() << collection->getSourceRange(); 1056 1057 // Check that the operand provides 1058 // - countByEnumeratingWithState:objects:count: 1059 const ObjCObjectType *objectType = pointerType->getObjectType(); 1060 ObjCInterfaceDecl *iface = objectType->getInterface(); 1061 1062 // If we have a forward-declared type, we can't do this check. 1063 // Under ARC, it is an error not to have a forward-declared class. 1064 if (iface && 1065 RequireCompleteType(forLoc, QualType(objectType, 0), 1066 getLangOptions().ObjCAutoRefCount 1067 ? PDiag(diag::err_arc_collection_forward) 1068 << collection->getSourceRange() 1069 : PDiag(0))) { 1070 // Otherwise, if we have any useful type information, check that 1071 // the type declares the appropriate method. 1072 } else if (iface || !objectType->qual_empty()) { 1073 IdentifierInfo *selectorIdents[] = { 1074 &Context.Idents.get("countByEnumeratingWithState"), 1075 &Context.Idents.get("objects"), 1076 &Context.Idents.get("count") 1077 }; 1078 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1079 1080 ObjCMethodDecl *method = 0; 1081 1082 // If there's an interface, look in both the public and private APIs. 1083 if (iface) { 1084 method = iface->lookupInstanceMethod(selector); 1085 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1086 } 1087 1088 // Also check protocol qualifiers. 1089 if (!method) 1090 method = LookupMethodInQualifiedType(selector, pointerType, 1091 /*instance*/ true); 1092 1093 // If we didn't find it anywhere, give up. 1094 if (!method) { 1095 Diag(forLoc, diag::warn_collection_expr_type) 1096 << collection->getType() << selector << collection->getSourceRange(); 1097 } 1098 1099 // TODO: check for an incompatible signature? 1100 } 1101 1102 // Wrap up any cleanups in the expression. 1103 return Owned(MaybeCreateExprWithCleanups(collection)); 1104} 1105 1106StmtResult 1107Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1108 SourceLocation LParenLoc, 1109 Stmt *First, Expr *Second, 1110 SourceLocation RParenLoc, Stmt *Body) { 1111 if (First) { 1112 QualType FirstType; 1113 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1114 if (!DS->isSingleDecl()) 1115 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1116 diag::err_toomany_element_decls)); 1117 1118 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1119 FirstType = D->getType(); 1120 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1121 // declare identifiers for objects having storage class 'auto' or 1122 // 'register'. 1123 if (!D->hasLocalStorage()) 1124 return StmtError(Diag(D->getLocation(), 1125 diag::err_non_variable_decl_in_for)); 1126 } else { 1127 Expr *FirstE = cast<Expr>(First); 1128 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1129 return StmtError(Diag(First->getLocStart(), 1130 diag::err_selector_element_not_lvalue) 1131 << First->getSourceRange()); 1132 1133 FirstType = static_cast<Expr*>(First)->getType(); 1134 } 1135 if (!FirstType->isDependentType() && 1136 !FirstType->isObjCObjectPointerType() && 1137 !FirstType->isBlockPointerType()) 1138 Diag(ForLoc, diag::err_selector_element_type) 1139 << FirstType << First->getSourceRange(); 1140 } 1141 1142 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1143 ForLoc, RParenLoc)); 1144} 1145 1146namespace { 1147 1148enum BeginEndFunction { 1149 BEF_begin, 1150 BEF_end 1151}; 1152 1153/// Build a variable declaration for a for-range statement. 1154static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1155 QualType Type, const char *Name) { 1156 DeclContext *DC = SemaRef.CurContext; 1157 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1158 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1159 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1160 TInfo, SC_Auto, SC_None); 1161 Decl->setImplicit(); 1162 return Decl; 1163} 1164 1165/// Finish building a variable declaration for a for-range statement. 1166/// \return true if an error occurs. 1167static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1168 SourceLocation Loc, int diag) { 1169 // Deduce the type for the iterator variable now rather than leaving it to 1170 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1171 TypeSourceInfo *InitTSI = 0; 1172 if (Init->getType()->isVoidType() || 1173 !SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI)) 1174 SemaRef.Diag(Loc, diag) << Init->getType(); 1175 if (!InitTSI) { 1176 Decl->setInvalidDecl(); 1177 return true; 1178 } 1179 Decl->setTypeSourceInfo(InitTSI); 1180 Decl->setType(InitTSI->getType()); 1181 1182 // In ARC, infer lifetime. 1183 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1184 // we're doing the equivalent of fast iteration. 1185 if (SemaRef.getLangOptions().ObjCAutoRefCount && 1186 SemaRef.inferObjCARCLifetime(Decl)) 1187 Decl->setInvalidDecl(); 1188 1189 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1190 /*TypeMayContainAuto=*/false); 1191 SemaRef.FinalizeDeclaration(Decl); 1192 SemaRef.CurContext->addHiddenDecl(Decl); 1193 return false; 1194} 1195 1196/// Produce a note indicating which begin/end function was implicitly called 1197/// by a C++0x for-range statement. This is often not obvious from the code, 1198/// nor from the diagnostics produced when analysing the implicit expressions 1199/// required in a for-range statement. 1200void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1201 BeginEndFunction BEF) { 1202 CallExpr *CE = dyn_cast<CallExpr>(E); 1203 if (!CE) 1204 return; 1205 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1206 if (!D) 1207 return; 1208 SourceLocation Loc = D->getLocation(); 1209 1210 std::string Description; 1211 bool IsTemplate = false; 1212 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1213 Description = SemaRef.getTemplateArgumentBindingsText( 1214 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1215 IsTemplate = true; 1216 } 1217 1218 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1219 << BEF << IsTemplate << Description << E->getType(); 1220} 1221 1222/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1223/// given LookupResult is non-empty, it is assumed to describe a member which 1224/// will be invoked. Otherwise, the function will be found via argument 1225/// dependent lookup. 1226static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1227 SourceLocation Loc, 1228 VarDecl *Decl, 1229 BeginEndFunction BEF, 1230 const DeclarationNameInfo &NameInfo, 1231 LookupResult &MemberLookup, 1232 Expr *Range) { 1233 ExprResult CallExpr; 1234 if (!MemberLookup.empty()) { 1235 ExprResult MemberRef = 1236 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1237 /*IsPtr=*/false, CXXScopeSpec(), 1238 /*Qualifier=*/0, MemberLookup, 1239 /*TemplateArgs=*/0); 1240 if (MemberRef.isInvalid()) 1241 return ExprError(); 1242 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1243 Loc, 0); 1244 if (CallExpr.isInvalid()) 1245 return ExprError(); 1246 } else { 1247 UnresolvedSet<0> FoundNames; 1248 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1249 // std is an associated namespace. 1250 UnresolvedLookupExpr *Fn = 1251 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1252 NestedNameSpecifierLoc(), NameInfo, 1253 /*NeedsADL=*/true, /*Overloaded=*/false, 1254 FoundNames.begin(), FoundNames.end(), 1255 /*LookInStdNamespace=*/true); 1256 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1257 0); 1258 if (CallExpr.isInvalid()) { 1259 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1260 << Range->getType(); 1261 return ExprError(); 1262 } 1263 } 1264 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1265 diag::err_for_range_iter_deduction_failure)) { 1266 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1267 return ExprError(); 1268 } 1269 return CallExpr; 1270} 1271 1272} 1273 1274/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1275/// 1276/// C++0x [stmt.ranged]: 1277/// A range-based for statement is equivalent to 1278/// 1279/// { 1280/// auto && __range = range-init; 1281/// for ( auto __begin = begin-expr, 1282/// __end = end-expr; 1283/// __begin != __end; 1284/// ++__begin ) { 1285/// for-range-declaration = *__begin; 1286/// statement 1287/// } 1288/// } 1289/// 1290/// The body of the loop is not available yet, since it cannot be analysed until 1291/// we have determined the type of the for-range-declaration. 1292StmtResult 1293Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1294 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1295 SourceLocation RParenLoc) { 1296 if (!First || !Range) 1297 return StmtError(); 1298 1299 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1300 assert(DS && "first part of for range not a decl stmt"); 1301 1302 if (!DS->isSingleDecl()) { 1303 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1304 return StmtError(); 1305 } 1306 if (DS->getSingleDecl()->isInvalidDecl()) 1307 return StmtError(); 1308 1309 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1310 return StmtError(); 1311 1312 // Build auto && __range = range-init 1313 SourceLocation RangeLoc = Range->getLocStart(); 1314 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1315 Context.getAutoRRefDeductType(), 1316 "__range"); 1317 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1318 diag::err_for_range_deduction_failure)) 1319 return StmtError(); 1320 1321 // Claim the type doesn't contain auto: we've already done the checking. 1322 DeclGroupPtrTy RangeGroup = 1323 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1324 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1325 if (RangeDecl.isInvalid()) 1326 return StmtError(); 1327 1328 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1329 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1330 RParenLoc); 1331} 1332 1333/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1334StmtResult 1335Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1336 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1337 Expr *Inc, Stmt *LoopVarDecl, 1338 SourceLocation RParenLoc) { 1339 Scope *S = getCurScope(); 1340 1341 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1342 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1343 QualType RangeVarType = RangeVar->getType(); 1344 1345 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1346 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1347 1348 StmtResult BeginEndDecl = BeginEnd; 1349 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1350 1351 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1352 SourceLocation RangeLoc = RangeVar->getLocation(); 1353 1354 const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType(); 1355 1356 ExprResult BeginRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1357 VK_LValue, ColonLoc); 1358 if (BeginRangeRef.isInvalid()) 1359 return StmtError(); 1360 1361 ExprResult EndRangeRef = BuildDeclRefExpr(RangeVar, RangeVarNonRefType, 1362 VK_LValue, ColonLoc); 1363 if (EndRangeRef.isInvalid()) 1364 return StmtError(); 1365 1366 QualType AutoType = Context.getAutoDeductType(); 1367 Expr *Range = RangeVar->getInit(); 1368 if (!Range) 1369 return StmtError(); 1370 QualType RangeType = Range->getType(); 1371 1372 if (RequireCompleteType(RangeLoc, RangeType, 1373 PDiag(diag::err_for_range_incomplete_type))) 1374 return StmtError(); 1375 1376 // Build auto __begin = begin-expr, __end = end-expr. 1377 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1378 "__begin"); 1379 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1380 "__end"); 1381 1382 // Build begin-expr and end-expr and attach to __begin and __end variables. 1383 ExprResult BeginExpr, EndExpr; 1384 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1385 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1386 // __range + __bound, respectively, where __bound is the array bound. If 1387 // _RangeT is an array of unknown size or an array of incomplete type, 1388 // the program is ill-formed; 1389 1390 // begin-expr is __range. 1391 BeginExpr = BeginRangeRef; 1392 if (FinishForRangeVarDecl(*this, BeginVar, BeginRangeRef.get(), ColonLoc, 1393 diag::err_for_range_iter_deduction_failure)) { 1394 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1395 return StmtError(); 1396 } 1397 1398 // Find the array bound. 1399 ExprResult BoundExpr; 1400 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1401 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1402 Context.getPointerDiffType(), 1403 RangeLoc)); 1404 else if (const VariableArrayType *VAT = 1405 dyn_cast<VariableArrayType>(UnqAT)) 1406 BoundExpr = VAT->getSizeExpr(); 1407 else { 1408 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1409 // UnqAT is not incomplete and Range is not type-dependent. 1410 llvm_unreachable("Unexpected array type in for-range"); 1411 } 1412 1413 // end-expr is __range + __bound. 1414 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, EndRangeRef.get(), 1415 BoundExpr.get()); 1416 if (EndExpr.isInvalid()) 1417 return StmtError(); 1418 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1419 diag::err_for_range_iter_deduction_failure)) { 1420 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1421 return StmtError(); 1422 } 1423 } else { 1424 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1425 ColonLoc); 1426 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1427 ColonLoc); 1428 1429 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1430 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1431 1432 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1433 // - if _RangeT is a class type, the unqualified-ids begin and end are 1434 // looked up in the scope of class _RangeT as if by class member access 1435 // lookup (3.4.5), and if either (or both) finds at least one 1436 // declaration, begin-expr and end-expr are __range.begin() and 1437 // __range.end(), respectively; 1438 LookupQualifiedName(BeginMemberLookup, D); 1439 LookupQualifiedName(EndMemberLookup, D); 1440 1441 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1442 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1443 << RangeType << BeginMemberLookup.empty(); 1444 return StmtError(); 1445 } 1446 } else { 1447 // - otherwise, begin-expr and end-expr are begin(__range) and 1448 // end(__range), respectively, where begin and end are looked up with 1449 // argument-dependent lookup (3.4.2). For the purposes of this name 1450 // lookup, namespace std is an associated namespace. 1451 } 1452 1453 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1454 BEF_begin, BeginNameInfo, 1455 BeginMemberLookup, 1456 BeginRangeRef.get()); 1457 if (BeginExpr.isInvalid()) 1458 return StmtError(); 1459 1460 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1461 BEF_end, EndNameInfo, 1462 EndMemberLookup, EndRangeRef.get()); 1463 if (EndExpr.isInvalid()) 1464 return StmtError(); 1465 } 1466 1467 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1468 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1469 if (!Context.hasSameType(BeginType, EndType)) { 1470 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1471 << BeginType << EndType; 1472 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1473 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1474 } 1475 1476 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1477 // Claim the type doesn't contain auto: we've already done the checking. 1478 DeclGroupPtrTy BeginEndGroup = 1479 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1480 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1481 1482 const QualType BeginRefNonRefType = BeginType.getNonReferenceType(); 1483 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1484 VK_LValue, ColonLoc); 1485 if (BeginRef.isInvalid()) 1486 return StmtError(); 1487 1488 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1489 VK_LValue, ColonLoc); 1490 if (EndRef.isInvalid()) 1491 return StmtError(); 1492 1493 // Build and check __begin != __end expression. 1494 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1495 BeginRef.get(), EndRef.get()); 1496 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1497 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1498 if (NotEqExpr.isInvalid()) { 1499 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1500 if (!Context.hasSameType(BeginType, EndType)) 1501 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1502 return StmtError(); 1503 } 1504 1505 // Build and check ++__begin expression. 1506 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1507 VK_LValue, ColonLoc); 1508 if (BeginRef.isInvalid()) 1509 return StmtError(); 1510 1511 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1512 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1513 if (IncrExpr.isInvalid()) { 1514 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1515 return StmtError(); 1516 } 1517 1518 // Build and check *__begin expression. 1519 BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType, 1520 VK_LValue, ColonLoc); 1521 if (BeginRef.isInvalid()) 1522 return StmtError(); 1523 1524 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1525 if (DerefExpr.isInvalid()) { 1526 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1527 return StmtError(); 1528 } 1529 1530 // Attach *__begin as initializer for VD. 1531 if (!LoopVar->isInvalidDecl()) { 1532 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1533 /*TypeMayContainAuto=*/true); 1534 if (LoopVar->isInvalidDecl()) 1535 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1536 } 1537 } else { 1538 // The range is implicitly used as a placeholder when it is dependent. 1539 RangeVar->setUsed(); 1540 } 1541 1542 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1543 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1544 NotEqExpr.take(), IncrExpr.take(), 1545 LoopVarDS, /*Body=*/0, ForLoc, 1546 ColonLoc, RParenLoc)); 1547} 1548 1549/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1550/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1551/// body cannot be performed until after the type of the range variable is 1552/// determined. 1553StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1554 if (!S || !B) 1555 return StmtError(); 1556 1557 cast<CXXForRangeStmt>(S)->setBody(B); 1558 return S; 1559} 1560 1561StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1562 SourceLocation LabelLoc, 1563 LabelDecl *TheDecl) { 1564 getCurFunction()->setHasBranchIntoScope(); 1565 TheDecl->setUsed(); 1566 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1567} 1568 1569StmtResult 1570Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1571 Expr *E) { 1572 // Convert operand to void* 1573 if (!E->isTypeDependent()) { 1574 QualType ETy = E->getType(); 1575 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1576 ExprResult ExprRes = Owned(E); 1577 AssignConvertType ConvTy = 1578 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1579 if (ExprRes.isInvalid()) 1580 return StmtError(); 1581 E = ExprRes.take(); 1582 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1583 return StmtError(); 1584 } 1585 1586 getCurFunction()->setHasIndirectGoto(); 1587 1588 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1589} 1590 1591StmtResult 1592Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1593 Scope *S = CurScope->getContinueParent(); 1594 if (!S) { 1595 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1596 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1597 } 1598 1599 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1600} 1601 1602StmtResult 1603Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1604 Scope *S = CurScope->getBreakParent(); 1605 if (!S) { 1606 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1607 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1608 } 1609 1610 return Owned(new (Context) BreakStmt(BreakLoc)); 1611} 1612 1613/// \brief Determine whether the given expression is a candidate for 1614/// copy elision in either a return statement or a throw expression. 1615/// 1616/// \param ReturnType If we're determining the copy elision candidate for 1617/// a return statement, this is the return type of the function. If we're 1618/// determining the copy elision candidate for a throw expression, this will 1619/// be a NULL type. 1620/// 1621/// \param E The expression being returned from the function or block, or 1622/// being thrown. 1623/// 1624/// \param AllowFunctionParameter Whether we allow function parameters to 1625/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1626/// we re-use this logic to determine whether we should try to move as part of 1627/// a return or throw (which does allow function parameters). 1628/// 1629/// \returns The NRVO candidate variable, if the return statement may use the 1630/// NRVO, or NULL if there is no such candidate. 1631const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1632 Expr *E, 1633 bool AllowFunctionParameter) { 1634 QualType ExprType = E->getType(); 1635 // - in a return statement in a function with ... 1636 // ... a class return type ... 1637 if (!ReturnType.isNull()) { 1638 if (!ReturnType->isRecordType()) 1639 return 0; 1640 // ... the same cv-unqualified type as the function return type ... 1641 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1642 return 0; 1643 } 1644 1645 // ... the expression is the name of a non-volatile automatic object 1646 // (other than a function or catch-clause parameter)) ... 1647 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1648 if (!DR) 1649 return 0; 1650 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1651 if (!VD) 1652 return 0; 1653 1654 // ...object (other than a function or catch-clause parameter)... 1655 if (VD->getKind() != Decl::Var && 1656 !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar)) 1657 return 0; 1658 if (VD->isExceptionVariable()) return 0; 1659 1660 // ...automatic... 1661 if (!VD->hasLocalStorage()) return 0; 1662 1663 // ...non-volatile... 1664 if (VD->getType().isVolatileQualified()) return 0; 1665 if (VD->getType()->isReferenceType()) return 0; 1666 1667 // __block variables can't be allocated in a way that permits NRVO. 1668 if (VD->hasAttr<BlocksAttr>()) return 0; 1669 1670 // Variables with higher required alignment than their type's ABI 1671 // alignment cannot use NRVO. 1672 if (VD->hasAttr<AlignedAttr>() && 1673 Context.getDeclAlign(VD) > Context.getTypeAlignInChars(VD->getType())) 1674 return 0; 1675 1676 return VD; 1677} 1678 1679/// \brief Perform the initialization of a potentially-movable value, which 1680/// is the result of return value. 1681/// 1682/// This routine implements C++0x [class.copy]p33, which attempts to treat 1683/// returned lvalues as rvalues in certain cases (to prefer move construction), 1684/// then falls back to treating them as lvalues if that failed. 1685ExprResult 1686Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1687 const VarDecl *NRVOCandidate, 1688 QualType ResultType, 1689 Expr *Value, 1690 bool AllowNRVO) { 1691 // C++0x [class.copy]p33: 1692 // When the criteria for elision of a copy operation are met or would 1693 // be met save for the fact that the source object is a function 1694 // parameter, and the object to be copied is designated by an lvalue, 1695 // overload resolution to select the constructor for the copy is first 1696 // performed as if the object were designated by an rvalue. 1697 ExprResult Res = ExprError(); 1698 if (AllowNRVO && 1699 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 1700 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1701 Value->getType(), CK_LValueToRValue, 1702 Value, VK_XValue); 1703 1704 Expr *InitExpr = &AsRvalue; 1705 InitializationKind Kind 1706 = InitializationKind::CreateCopy(Value->getLocStart(), 1707 Value->getLocStart()); 1708 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1709 1710 // [...] If overload resolution fails, or if the type of the first 1711 // parameter of the selected constructor is not an rvalue reference 1712 // to the object's type (possibly cv-qualified), overload resolution 1713 // is performed again, considering the object as an lvalue. 1714 if (Seq) { 1715 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1716 StepEnd = Seq.step_end(); 1717 Step != StepEnd; ++Step) { 1718 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 1719 continue; 1720 1721 CXXConstructorDecl *Constructor 1722 = cast<CXXConstructorDecl>(Step->Function.Function); 1723 1724 const RValueReferenceType *RRefType 1725 = Constructor->getParamDecl(0)->getType() 1726 ->getAs<RValueReferenceType>(); 1727 1728 // If we don't meet the criteria, break out now. 1729 if (!RRefType || 1730 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1731 Context.getTypeDeclType(Constructor->getParent()))) 1732 break; 1733 1734 // Promote "AsRvalue" to the heap, since we now need this 1735 // expression node to persist. 1736 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1737 CK_LValueToRValue, Value, 0, 1738 VK_XValue); 1739 1740 // Complete type-checking the initialization of the return type 1741 // using the constructor we found. 1742 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1743 } 1744 } 1745 } 1746 1747 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1748 // above, or overload resolution failed. Either way, we need to try 1749 // (again) now with the return value expression as written. 1750 if (Res.isInvalid()) 1751 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1752 1753 return Res; 1754} 1755 1756/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1757/// 1758StmtResult 1759Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1760 // If this is the first return we've seen in the block, infer the type of 1761 // the block from it. 1762 BlockScopeInfo *CurBlock = getCurBlock(); 1763 if (CurBlock->TheDecl->blockMissingReturnType()) { 1764 QualType BlockReturnT; 1765 if (RetValExp) { 1766 // Don't call UsualUnaryConversions(), since we don't want to do 1767 // integer promotions here. 1768 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 1769 if (Result.isInvalid()) 1770 return StmtError(); 1771 RetValExp = Result.take(); 1772 1773 if (!RetValExp->isTypeDependent()) { 1774 BlockReturnT = RetValExp->getType(); 1775 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1776 // We have to remove a 'const' added to copied-in variable which was 1777 // part of the implementation spec. and not the actual qualifier for 1778 // the variable. 1779 if (CDRE->isConstQualAdded()) 1780 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1781 } 1782 } else 1783 BlockReturnT = Context.DependentTy; 1784 } else 1785 BlockReturnT = Context.VoidTy; 1786 if (!CurBlock->ReturnType.isNull() && !CurBlock->ReturnType->isDependentType() 1787 && !BlockReturnT->isDependentType() 1788 // when block's return type is not specified, all return types 1789 // must strictly match. 1790 && !Context.hasSameType(BlockReturnT, CurBlock->ReturnType)) { 1791 Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible) 1792 << BlockReturnT << CurBlock->ReturnType; 1793 return StmtError(); 1794 } 1795 CurBlock->ReturnType = BlockReturnT; 1796 } 1797 QualType FnRetType = CurBlock->ReturnType; 1798 1799 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1800 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1801 << getCurFunctionOrMethodDecl()->getDeclName(); 1802 return StmtError(); 1803 } 1804 1805 // Otherwise, verify that this result type matches the previous one. We are 1806 // pickier with blocks than for normal functions because we don't have GCC 1807 // compatibility to worry about here. 1808 const VarDecl *NRVOCandidate = 0; 1809 if (FnRetType->isDependentType()) { 1810 // Delay processing for now. TODO: there are lots of dependent 1811 // types we can conclusively prove aren't void. 1812 } else if (FnRetType->isVoidType()) { 1813 if (RetValExp && 1814 !(getLangOptions().CPlusPlus && 1815 (RetValExp->isTypeDependent() || 1816 RetValExp->getType()->isVoidType()))) { 1817 Diag(ReturnLoc, diag::err_return_block_has_expr); 1818 RetValExp = 0; 1819 } 1820 } else if (!RetValExp) { 1821 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1822 } else if (!RetValExp->isTypeDependent()) { 1823 // we have a non-void block with an expression, continue checking 1824 1825 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1826 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1827 // function return. 1828 1829 // In C++ the return statement is handled via a copy initialization. 1830 // the C version of which boils down to CheckSingleAssignmentConstraints. 1831 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1832 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1833 FnRetType, 1834 NRVOCandidate != 0); 1835 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1836 FnRetType, RetValExp); 1837 if (Res.isInvalid()) { 1838 // FIXME: Cleanup temporaries here, anyway? 1839 return StmtError(); 1840 } 1841 RetValExp = Res.take(); 1842 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1843 } 1844 1845 if (RetValExp) { 1846 CheckImplicitConversions(RetValExp, ReturnLoc); 1847 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1848 } 1849 ReturnStmt *Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 1850 NRVOCandidate); 1851 1852 // If we need to check for the named return value optimization, save the 1853 // return statement in our scope for later processing. 1854 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1855 !CurContext->isDependentContext()) 1856 FunctionScopes.back()->Returns.push_back(Result); 1857 1858 return Owned(Result); 1859} 1860 1861StmtResult 1862Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1863 // Check for unexpanded parameter packs. 1864 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 1865 return StmtError(); 1866 1867 if (getCurBlock()) 1868 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1869 1870 QualType FnRetType; 1871 QualType DeclaredRetType; 1872 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1873 FnRetType = FD->getResultType(); 1874 DeclaredRetType = FnRetType; 1875 if (FD->hasAttr<NoReturnAttr>() || 1876 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1877 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1878 << getCurFunctionOrMethodDecl()->getDeclName(); 1879 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 1880 DeclaredRetType = MD->getResultType(); 1881 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 1882 // In the implementation of a method with a related return type, the 1883 // type used to type-check the validity of return statements within the 1884 // method body is a pointer to the type of the class being implemented. 1885 FnRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 1886 FnRetType = Context.getObjCObjectPointerType(FnRetType); 1887 } else { 1888 FnRetType = DeclaredRetType; 1889 } 1890 } else // If we don't have a function/method context, bail. 1891 return StmtError(); 1892 1893 ReturnStmt *Result = 0; 1894 if (FnRetType->isVoidType()) { 1895 if (RetValExp) { 1896 if (!RetValExp->isTypeDependent()) { 1897 // C99 6.8.6.4p1 (ext_ since GCC warns) 1898 unsigned D = diag::ext_return_has_expr; 1899 if (RetValExp->getType()->isVoidType()) 1900 D = diag::ext_return_has_void_expr; 1901 else { 1902 ExprResult Result = Owned(RetValExp); 1903 Result = IgnoredValueConversions(Result.take()); 1904 if (Result.isInvalid()) 1905 return StmtError(); 1906 RetValExp = Result.take(); 1907 RetValExp = ImpCastExprToType(RetValExp, 1908 Context.VoidTy, CK_ToVoid).take(); 1909 } 1910 1911 // return (some void expression); is legal in C++. 1912 if (D != diag::ext_return_has_void_expr || 1913 !getLangOptions().CPlusPlus) { 1914 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1915 1916 int FunctionKind = 0; 1917 if (isa<ObjCMethodDecl>(CurDecl)) 1918 FunctionKind = 1; 1919 else if (isa<CXXConstructorDecl>(CurDecl)) 1920 FunctionKind = 2; 1921 else if (isa<CXXDestructorDecl>(CurDecl)) 1922 FunctionKind = 3; 1923 1924 Diag(ReturnLoc, D) 1925 << CurDecl->getDeclName() << FunctionKind 1926 << RetValExp->getSourceRange(); 1927 } 1928 } 1929 1930 CheckImplicitConversions(RetValExp, ReturnLoc); 1931 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1932 } 1933 1934 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1935 } else if (!RetValExp && !FnRetType->isDependentType()) { 1936 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1937 // C99 6.8.6.4p1 (ext_ since GCC warns) 1938 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1939 1940 if (FunctionDecl *FD = getCurFunctionDecl()) 1941 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1942 else 1943 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1944 Result = new (Context) ReturnStmt(ReturnLoc); 1945 } else { 1946 const VarDecl *NRVOCandidate = 0; 1947 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1948 // we have a non-void function with an expression, continue checking 1949 1950 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1951 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1952 // function return. 1953 1954 // In C++ the return statement is handled via a copy initialization, 1955 // the C version of which boils down to CheckSingleAssignmentConstraints. 1956 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1957 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1958 FnRetType, 1959 NRVOCandidate != 0); 1960 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1961 FnRetType, RetValExp); 1962 if (Res.isInvalid()) { 1963 // FIXME: Cleanup temporaries here, anyway? 1964 return StmtError(); 1965 } 1966 1967 RetValExp = Res.takeAs<Expr>(); 1968 if (RetValExp) 1969 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1970 } 1971 1972 if (RetValExp) { 1973 // If we type-checked an Objective-C method's return type based 1974 // on a related return type, we may need to adjust the return 1975 // type again. Do so now. 1976 if (DeclaredRetType != FnRetType) { 1977 ExprResult result = PerformImplicitConversion(RetValExp, 1978 DeclaredRetType, 1979 AA_Returning); 1980 if (result.isInvalid()) return StmtError(); 1981 RetValExp = result.take(); 1982 } 1983 1984 CheckImplicitConversions(RetValExp, ReturnLoc); 1985 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1986 } 1987 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1988 } 1989 1990 // If we need to check for the named return value optimization, save the 1991 // return statement in our scope for later processing. 1992 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1993 !CurContext->isDependentContext()) 1994 FunctionScopes.back()->Returns.push_back(Result); 1995 1996 return Owned(Result); 1997} 1998 1999/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 2000/// ignore "noop" casts in places where an lvalue is required by an inline asm. 2001/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 2002/// provide a strong guidance to not use it. 2003/// 2004/// This method checks to see if the argument is an acceptable l-value and 2005/// returns false if it is a case we can handle. 2006static bool CheckAsmLValue(const Expr *E, Sema &S) { 2007 // Type dependent expressions will be checked during instantiation. 2008 if (E->isTypeDependent()) 2009 return false; 2010 2011 if (E->isLValue()) 2012 return false; // Cool, this is an lvalue. 2013 2014 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 2015 // are supposed to allow. 2016 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 2017 if (E != E2 && E2->isLValue()) { 2018 if (!S.getLangOptions().HeinousExtensions) 2019 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 2020 << E->getSourceRange(); 2021 else 2022 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 2023 << E->getSourceRange(); 2024 // Accept, even if we emitted an error diagnostic. 2025 return false; 2026 } 2027 2028 // None of the above, just randomly invalid non-lvalue. 2029 return true; 2030} 2031 2032/// isOperandMentioned - Return true if the specified operand # is mentioned 2033/// anywhere in the decomposed asm string. 2034static bool isOperandMentioned(unsigned OpNo, 2035 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 2036 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 2037 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 2038 if (!Piece.isOperand()) continue; 2039 2040 // If this is a reference to the input and if the input was the smaller 2041 // one, then we have to reject this asm. 2042 if (Piece.getOperandNo() == OpNo) 2043 return true; 2044 } 2045 2046 return false; 2047} 2048 2049StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 2050 bool IsVolatile, unsigned NumOutputs, 2051 unsigned NumInputs, IdentifierInfo **Names, 2052 MultiExprArg constraints, MultiExprArg exprs, 2053 Expr *asmString, MultiExprArg clobbers, 2054 SourceLocation RParenLoc, bool MSAsm) { 2055 unsigned NumClobbers = clobbers.size(); 2056 StringLiteral **Constraints = 2057 reinterpret_cast<StringLiteral**>(constraints.get()); 2058 Expr **Exprs = exprs.get(); 2059 StringLiteral *AsmString = cast<StringLiteral>(asmString); 2060 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 2061 2062 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 2063 2064 // The parser verifies that there is a string literal here. 2065 if (!AsmString->isAscii()) 2066 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 2067 << AsmString->getSourceRange()); 2068 2069 for (unsigned i = 0; i != NumOutputs; i++) { 2070 StringLiteral *Literal = Constraints[i]; 2071 if (!Literal->isAscii()) 2072 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2073 << Literal->getSourceRange()); 2074 2075 StringRef OutputName; 2076 if (Names[i]) 2077 OutputName = Names[i]->getName(); 2078 2079 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 2080 if (!Context.getTargetInfo().validateOutputConstraint(Info)) 2081 return StmtError(Diag(Literal->getLocStart(), 2082 diag::err_asm_invalid_output_constraint) 2083 << Info.getConstraintStr()); 2084 2085 // Check that the output exprs are valid lvalues. 2086 Expr *OutputExpr = Exprs[i]; 2087 if (CheckAsmLValue(OutputExpr, *this)) { 2088 return StmtError(Diag(OutputExpr->getLocStart(), 2089 diag::err_asm_invalid_lvalue_in_output) 2090 << OutputExpr->getSourceRange()); 2091 } 2092 2093 OutputConstraintInfos.push_back(Info); 2094 } 2095 2096 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 2097 2098 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 2099 StringLiteral *Literal = Constraints[i]; 2100 if (!Literal->isAscii()) 2101 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2102 << Literal->getSourceRange()); 2103 2104 StringRef InputName; 2105 if (Names[i]) 2106 InputName = Names[i]->getName(); 2107 2108 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 2109 if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos.data(), 2110 NumOutputs, Info)) { 2111 return StmtError(Diag(Literal->getLocStart(), 2112 diag::err_asm_invalid_input_constraint) 2113 << Info.getConstraintStr()); 2114 } 2115 2116 Expr *InputExpr = Exprs[i]; 2117 2118 // Only allow void types for memory constraints. 2119 if (Info.allowsMemory() && !Info.allowsRegister()) { 2120 if (CheckAsmLValue(InputExpr, *this)) 2121 return StmtError(Diag(InputExpr->getLocStart(), 2122 diag::err_asm_invalid_lvalue_in_input) 2123 << Info.getConstraintStr() 2124 << InputExpr->getSourceRange()); 2125 } 2126 2127 if (Info.allowsRegister()) { 2128 if (InputExpr->getType()->isVoidType()) { 2129 return StmtError(Diag(InputExpr->getLocStart(), 2130 diag::err_asm_invalid_type_in_input) 2131 << InputExpr->getType() << Info.getConstraintStr() 2132 << InputExpr->getSourceRange()); 2133 } 2134 } 2135 2136 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2137 if (Result.isInvalid()) 2138 return StmtError(); 2139 2140 Exprs[i] = Result.take(); 2141 InputConstraintInfos.push_back(Info); 2142 } 2143 2144 // Check that the clobbers are valid. 2145 for (unsigned i = 0; i != NumClobbers; i++) { 2146 StringLiteral *Literal = Clobbers[i]; 2147 if (!Literal->isAscii()) 2148 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2149 << Literal->getSourceRange()); 2150 2151 StringRef Clobber = Literal->getString(); 2152 2153 if (!Context.getTargetInfo().isValidClobber(Clobber)) 2154 return StmtError(Diag(Literal->getLocStart(), 2155 diag::err_asm_unknown_register_name) << Clobber); 2156 } 2157 2158 AsmStmt *NS = 2159 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2160 NumOutputs, NumInputs, Names, Constraints, Exprs, 2161 AsmString, NumClobbers, Clobbers, RParenLoc); 2162 // Validate the asm string, ensuring it makes sense given the operands we 2163 // have. 2164 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2165 unsigned DiagOffs; 2166 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2167 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2168 << AsmString->getSourceRange(); 2169 return StmtError(); 2170 } 2171 2172 // Validate tied input operands for type mismatches. 2173 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2174 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2175 2176 // If this is a tied constraint, verify that the output and input have 2177 // either exactly the same type, or that they are int/ptr operands with the 2178 // same size (int/long, int*/long, are ok etc). 2179 if (!Info.hasTiedOperand()) continue; 2180 2181 unsigned TiedTo = Info.getTiedOperand(); 2182 unsigned InputOpNo = i+NumOutputs; 2183 Expr *OutputExpr = Exprs[TiedTo]; 2184 Expr *InputExpr = Exprs[InputOpNo]; 2185 2186 if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent()) 2187 continue; 2188 2189 QualType InTy = InputExpr->getType(); 2190 QualType OutTy = OutputExpr->getType(); 2191 if (Context.hasSameType(InTy, OutTy)) 2192 continue; // All types can be tied to themselves. 2193 2194 // Decide if the input and output are in the same domain (integer/ptr or 2195 // floating point. 2196 enum AsmDomain { 2197 AD_Int, AD_FP, AD_Other 2198 } InputDomain, OutputDomain; 2199 2200 if (InTy->isIntegerType() || InTy->isPointerType()) 2201 InputDomain = AD_Int; 2202 else if (InTy->isRealFloatingType()) 2203 InputDomain = AD_FP; 2204 else 2205 InputDomain = AD_Other; 2206 2207 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2208 OutputDomain = AD_Int; 2209 else if (OutTy->isRealFloatingType()) 2210 OutputDomain = AD_FP; 2211 else 2212 OutputDomain = AD_Other; 2213 2214 // They are ok if they are the same size and in the same domain. This 2215 // allows tying things like: 2216 // void* to int* 2217 // void* to int if they are the same size. 2218 // double to long double if they are the same size. 2219 // 2220 uint64_t OutSize = Context.getTypeSize(OutTy); 2221 uint64_t InSize = Context.getTypeSize(InTy); 2222 if (OutSize == InSize && InputDomain == OutputDomain && 2223 InputDomain != AD_Other) 2224 continue; 2225 2226 // If the smaller input/output operand is not mentioned in the asm string, 2227 // then we can promote the smaller one to a larger input and the asm string 2228 // won't notice. 2229 bool SmallerValueMentioned = false; 2230 2231 // If this is a reference to the input and if the input was the smaller 2232 // one, then we have to reject this asm. 2233 if (isOperandMentioned(InputOpNo, Pieces)) { 2234 // This is a use in the asm string of the smaller operand. Since we 2235 // codegen this by promoting to a wider value, the asm will get printed 2236 // "wrong". 2237 SmallerValueMentioned |= InSize < OutSize; 2238 } 2239 if (isOperandMentioned(TiedTo, Pieces)) { 2240 // If this is a reference to the output, and if the output is the larger 2241 // value, then it's ok because we'll promote the input to the larger type. 2242 SmallerValueMentioned |= OutSize < InSize; 2243 } 2244 2245 // If the smaller value wasn't mentioned in the asm string, and if the 2246 // output was a register, just extend the shorter one to the size of the 2247 // larger one. 2248 if (!SmallerValueMentioned && InputDomain != AD_Other && 2249 OutputConstraintInfos[TiedTo].allowsRegister()) 2250 continue; 2251 2252 // Either both of the operands were mentioned or the smaller one was 2253 // mentioned. One more special case that we'll allow: if the tied input is 2254 // integer, unmentioned, and is a constant, then we'll allow truncating it 2255 // down to the size of the destination. 2256 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2257 !isOperandMentioned(InputOpNo, Pieces) && 2258 InputExpr->isEvaluatable(Context)) { 2259 CastKind castKind = 2260 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2261 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2262 Exprs[InputOpNo] = InputExpr; 2263 NS->setInputExpr(i, InputExpr); 2264 continue; 2265 } 2266 2267 Diag(InputExpr->getLocStart(), 2268 diag::err_asm_tying_incompatible_types) 2269 << InTy << OutTy << OutputExpr->getSourceRange() 2270 << InputExpr->getSourceRange(); 2271 return StmtError(); 2272 } 2273 2274 return Owned(NS); 2275} 2276 2277StmtResult 2278Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2279 SourceLocation RParen, Decl *Parm, 2280 Stmt *Body) { 2281 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2282 if (Var && Var->isInvalidDecl()) 2283 return StmtError(); 2284 2285 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2286} 2287 2288StmtResult 2289Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2290 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2291} 2292 2293StmtResult 2294Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2295 MultiStmtArg CatchStmts, Stmt *Finally) { 2296 if (!getLangOptions().ObjCExceptions) 2297 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2298 2299 getCurFunction()->setHasBranchProtectedScope(); 2300 unsigned NumCatchStmts = CatchStmts.size(); 2301 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2302 CatchStmts.release(), 2303 NumCatchStmts, 2304 Finally)); 2305} 2306 2307StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 2308 Expr *Throw) { 2309 if (Throw) { 2310 Throw = MaybeCreateExprWithCleanups(Throw); 2311 ExprResult Result = DefaultLvalueConversion(Throw); 2312 if (Result.isInvalid()) 2313 return StmtError(); 2314 2315 Throw = Result.take(); 2316 QualType ThrowType = Throw->getType(); 2317 // Make sure the expression type is an ObjC pointer or "void *". 2318 if (!ThrowType->isDependentType() && 2319 !ThrowType->isObjCObjectPointerType()) { 2320 const PointerType *PT = ThrowType->getAs<PointerType>(); 2321 if (!PT || !PT->getPointeeType()->isVoidType()) 2322 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2323 << Throw->getType() << Throw->getSourceRange()); 2324 } 2325 } 2326 2327 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2328} 2329 2330StmtResult 2331Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2332 Scope *CurScope) { 2333 if (!getLangOptions().ObjCExceptions) 2334 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2335 2336 if (!Throw) { 2337 // @throw without an expression designates a rethrow (which much occur 2338 // in the context of an @catch clause). 2339 Scope *AtCatchParent = CurScope; 2340 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2341 AtCatchParent = AtCatchParent->getParent(); 2342 if (!AtCatchParent) 2343 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2344 } 2345 2346 return BuildObjCAtThrowStmt(AtLoc, Throw); 2347} 2348 2349ExprResult 2350Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) { 2351 ExprResult result = DefaultLvalueConversion(operand); 2352 if (result.isInvalid()) 2353 return ExprError(); 2354 operand = result.take(); 2355 2356 // Make sure the expression type is an ObjC pointer or "void *". 2357 QualType type = operand->getType(); 2358 if (!type->isDependentType() && 2359 !type->isObjCObjectPointerType()) { 2360 const PointerType *pointerType = type->getAs<PointerType>(); 2361 if (!pointerType || !pointerType->getPointeeType()->isVoidType()) 2362 return Diag(atLoc, diag::error_objc_synchronized_expects_object) 2363 << type << operand->getSourceRange(); 2364 } 2365 2366 // The operand to @synchronized is a full-expression. 2367 return MaybeCreateExprWithCleanups(operand); 2368} 2369 2370StmtResult 2371Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2372 Stmt *SyncBody) { 2373 // We can't jump into or indirect-jump out of a @synchronized block. 2374 getCurFunction()->setHasBranchProtectedScope(); 2375 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2376} 2377 2378/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2379/// and creates a proper catch handler from them. 2380StmtResult 2381Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2382 Stmt *HandlerBlock) { 2383 // There's nothing to test that ActOnExceptionDecl didn't already test. 2384 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2385 cast_or_null<VarDecl>(ExDecl), 2386 HandlerBlock)); 2387} 2388 2389StmtResult 2390Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2391 getCurFunction()->setHasBranchProtectedScope(); 2392 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2393} 2394 2395namespace { 2396 2397class TypeWithHandler { 2398 QualType t; 2399 CXXCatchStmt *stmt; 2400public: 2401 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2402 : t(type), stmt(statement) {} 2403 2404 // An arbitrary order is fine as long as it places identical 2405 // types next to each other. 2406 bool operator<(const TypeWithHandler &y) const { 2407 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2408 return true; 2409 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2410 return false; 2411 else 2412 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2413 } 2414 2415 bool operator==(const TypeWithHandler& other) const { 2416 return t == other.t; 2417 } 2418 2419 CXXCatchStmt *getCatchStmt() const { return stmt; } 2420 SourceLocation getTypeSpecStartLoc() const { 2421 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2422 } 2423}; 2424 2425} 2426 2427/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2428/// handlers and creates a try statement from them. 2429StmtResult 2430Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2431 MultiStmtArg RawHandlers) { 2432 // Don't report an error if 'try' is used in system headers. 2433 if (!getLangOptions().CXXExceptions && 2434 !getSourceManager().isInSystemHeader(TryLoc)) 2435 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2436 2437 unsigned NumHandlers = RawHandlers.size(); 2438 assert(NumHandlers > 0 && 2439 "The parser shouldn't call this if there are no handlers."); 2440 Stmt **Handlers = RawHandlers.get(); 2441 2442 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2443 2444 for (unsigned i = 0; i < NumHandlers; ++i) { 2445 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2446 if (!Handler->getExceptionDecl()) { 2447 if (i < NumHandlers - 1) 2448 return StmtError(Diag(Handler->getLocStart(), 2449 diag::err_early_catch_all)); 2450 2451 continue; 2452 } 2453 2454 const QualType CaughtType = Handler->getCaughtType(); 2455 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2456 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2457 } 2458 2459 // Detect handlers for the same type as an earlier one. 2460 if (NumHandlers > 1) { 2461 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2462 2463 TypeWithHandler prev = TypesWithHandlers[0]; 2464 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2465 TypeWithHandler curr = TypesWithHandlers[i]; 2466 2467 if (curr == prev) { 2468 Diag(curr.getTypeSpecStartLoc(), 2469 diag::warn_exception_caught_by_earlier_handler) 2470 << curr.getCatchStmt()->getCaughtType().getAsString(); 2471 Diag(prev.getTypeSpecStartLoc(), 2472 diag::note_previous_exception_handler) 2473 << prev.getCatchStmt()->getCaughtType().getAsString(); 2474 } 2475 2476 prev = curr; 2477 } 2478 } 2479 2480 getCurFunction()->setHasBranchProtectedScope(); 2481 2482 // FIXME: We should detect handlers that cannot catch anything because an 2483 // earlier handler catches a superclass. Need to find a method that is not 2484 // quadratic for this. 2485 // Neither of these are explicitly forbidden, but every compiler detects them 2486 // and warns. 2487 2488 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2489 Handlers, NumHandlers)); 2490} 2491 2492StmtResult 2493Sema::ActOnSEHTryBlock(bool IsCXXTry, 2494 SourceLocation TryLoc, 2495 Stmt *TryBlock, 2496 Stmt *Handler) { 2497 assert(TryBlock && Handler); 2498 2499 getCurFunction()->setHasBranchProtectedScope(); 2500 2501 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2502} 2503 2504StmtResult 2505Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2506 Expr *FilterExpr, 2507 Stmt *Block) { 2508 assert(FilterExpr && Block); 2509 2510 if(!FilterExpr->getType()->isIntegerType()) { 2511 return StmtError(Diag(FilterExpr->getExprLoc(), 2512 diag::err_filter_expression_integral) 2513 << FilterExpr->getType()); 2514 } 2515 2516 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2517} 2518 2519StmtResult 2520Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2521 Stmt *Block) { 2522 assert(Block); 2523 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2524} 2525 2526StmtResult Sema::BuildMSDependentExistsStmt(SourceLocation KeywordLoc, 2527 bool IsIfExists, 2528 NestedNameSpecifierLoc QualifierLoc, 2529 DeclarationNameInfo NameInfo, 2530 Stmt *Nested) 2531{ 2532 return new (Context) MSDependentExistsStmt(KeywordLoc, IsIfExists, 2533 QualifierLoc, NameInfo, 2534 cast<CompoundStmt>(Nested)); 2535} 2536 2537 2538StmtResult Sema::ActOnMSDependentExistsStmt(SourceLocation KeywordLoc, 2539 bool IsIfExists, 2540 CXXScopeSpec &SS, 2541 UnqualifiedId &Name, 2542 Stmt *Nested) { 2543 return BuildMSDependentExistsStmt(KeywordLoc, IsIfExists, 2544 SS.getWithLocInContext(Context), 2545 GetNameFromUnqualifiedId(Name), 2546 Nested); 2547} 2548