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