SemaStmt.cpp revision 5cee1195584fa8672253139c86e922daeda69b9e
1//===--- SemaStmt.cpp - Semantic Analysis for Statements ------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements semantic analysis for statements. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Sema/SemaInternal.h" 15#include "clang/Sema/Scope.h" 16#include "clang/Sema/ScopeInfo.h" 17#include "clang/Sema/Initialization.h" 18#include "clang/Sema/Lookup.h" 19#include "clang/AST/APValue.h" 20#include "clang/AST/ASTContext.h" 21#include "clang/AST/DeclObjC.h" 22#include "clang/AST/ExprCXX.h" 23#include "clang/AST/ExprObjC.h" 24#include "clang/AST/StmtObjC.h" 25#include "clang/AST/StmtCXX.h" 26#include "clang/AST/TypeLoc.h" 27#include "clang/Lex/Preprocessor.h" 28#include "clang/Basic/TargetInfo.h" 29#include "llvm/ADT/ArrayRef.h" 30#include "llvm/ADT/STLExtras.h" 31#include "llvm/ADT/SmallVector.h" 32using namespace clang; 33using namespace sema; 34 35StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 36 Expr *E = expr.get(); 37 if (!E) // FIXME: FullExprArg has no error state? 38 return StmtError(); 39 40 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 41 // void expression for its side effects. Conversion to void allows any 42 // operand, even incomplete types. 43 44 // Same thing in for stmt first clause (when expr) and third clause. 45 return Owned(static_cast<Stmt*>(E)); 46} 47 48 49StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, 50 SourceLocation LeadingEmptyMacroLoc) { 51 return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacroLoc)); 52} 53 54StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 55 SourceLocation EndLoc) { 56 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 57 58 // If we have an invalid decl, just return an error. 59 if (DG.isNull()) return StmtError(); 60 61 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 62} 63 64void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 65 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 66 67 // If we have an invalid decl, just return. 68 if (DG.isNull() || !DG.isSingleDecl()) return; 69 VarDecl *var = cast<VarDecl>(DG.getSingleDecl()); 70 71 // suppress any potential 'unused variable' warning. 72 var->setUsed(); 73 74 // foreach variables are never actually initialized in the way that 75 // the parser came up with. 76 var->setInit(0); 77 78 // In ARC, we don't need to retain the iteration variable of a fast 79 // enumeration loop. Rather than actually trying to catch that 80 // during declaration processing, we remove the consequences here. 81 if (getLangOptions().ObjCAutoRefCount) { 82 QualType type = var->getType(); 83 84 // Only do this if we inferred the lifetime. Inferred lifetime 85 // will show up as a local qualifier because explicit lifetime 86 // should have shown up as an AttributedType instead. 87 if (type.getLocalQualifiers().getObjCLifetime() == Qualifiers::OCL_Strong) { 88 // Add 'const' and mark the variable as pseudo-strong. 89 var->setType(type.withConst()); 90 var->setARCPseudoStrong(true); 91 } 92 } 93} 94 95void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 96 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 97 return DiagnoseUnusedExprResult(Label->getSubStmt()); 98 99 const Expr *E = dyn_cast_or_null<Expr>(S); 100 if (!E) 101 return; 102 103 SourceLocation Loc; 104 SourceRange R1, R2; 105 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 106 return; 107 108 // Okay, we have an unused result. Depending on what the base expression is, 109 // we might want to make a more specific diagnostic. Check for one of these 110 // cases now. 111 unsigned DiagID = diag::warn_unused_expr; 112 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 113 E = Temps->getSubExpr(); 114 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 115 E = TempExpr->getSubExpr(); 116 117 E = E->IgnoreParenImpCasts(); 118 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 119 if (E->getType()->isVoidType()) 120 return; 121 122 // If the callee has attribute pure, const, or warn_unused_result, warn with 123 // a more specific message to make it clear what is happening. 124 if (const Decl *FD = CE->getCalleeDecl()) { 125 if (FD->getAttr<WarnUnusedResultAttr>()) { 126 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 127 return; 128 } 129 if (FD->getAttr<PureAttr>()) { 130 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 131 return; 132 } 133 if (FD->getAttr<ConstAttr>()) { 134 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 135 return; 136 } 137 } 138 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 139 if (getLangOptions().ObjCAutoRefCount && ME->isDelegateInitCall()) { 140 Diag(Loc, diag::err_arc_unused_init_message) << R1; 141 return; 142 } 143 const ObjCMethodDecl *MD = ME->getMethodDecl(); 144 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 145 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 146 return; 147 } 148 } else if (isa<ObjCPropertyRefExpr>(E)) { 149 DiagID = diag::warn_unused_property_expr; 150 } else if (const CXXFunctionalCastExpr *FC 151 = dyn_cast<CXXFunctionalCastExpr>(E)) { 152 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 153 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 154 return; 155 } 156 // Diagnose "(void*) blah" as a typo for "(void) blah". 157 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 158 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 159 QualType T = TI->getType(); 160 161 // We really do want to use the non-canonical type here. 162 if (T == Context.VoidPtrTy) { 163 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 164 165 Diag(Loc, diag::warn_unused_voidptr) 166 << FixItHint::CreateRemoval(TL.getStarLoc()); 167 return; 168 } 169 } 170 171 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 172} 173 174StmtResult 175Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 176 MultiStmtArg elts, bool isStmtExpr) { 177 unsigned NumElts = elts.size(); 178 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 179 // If we're in C89 mode, check that we don't have any decls after stmts. If 180 // so, emit an extension diagnostic. 181 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 182 // Note that __extension__ can be around a decl. 183 unsigned i = 0; 184 // Skip over all declarations. 185 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 186 /*empty*/; 187 188 // We found the end of the list or a statement. Scan for another declstmt. 189 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 190 /*empty*/; 191 192 if (i != NumElts) { 193 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 194 Diag(D->getLocation(), diag::ext_mixed_decls_code); 195 } 196 } 197 // Warn about unused expressions in statements. 198 for (unsigned i = 0; i != NumElts; ++i) { 199 // Ignore statements that are last in a statement expression. 200 if (isStmtExpr && i == NumElts - 1) 201 continue; 202 203 DiagnoseUnusedExprResult(Elts[i]); 204 } 205 206 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 207} 208 209StmtResult 210Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 211 SourceLocation DotDotDotLoc, Expr *RHSVal, 212 SourceLocation ColonLoc) { 213 assert((LHSVal != 0) && "missing expression in case statement"); 214 215 // C99 6.8.4.2p3: The expression shall be an integer constant. 216 // However, GCC allows any evaluatable integer expression. 217 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 218 VerifyIntegerConstantExpression(LHSVal)) 219 return StmtError(); 220 221 // GCC extension: The expression shall be an integer constant. 222 223 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 224 VerifyIntegerConstantExpression(RHSVal)) { 225 RHSVal = 0; // Recover by just forgetting about it. 226 } 227 228 if (getCurFunction()->SwitchStack.empty()) { 229 Diag(CaseLoc, diag::err_case_not_in_switch); 230 return StmtError(); 231 } 232 233 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 234 ColonLoc); 235 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 236 return Owned(CS); 237} 238 239/// ActOnCaseStmtBody - This installs a statement as the body of a case. 240void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 241 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 242 CS->setSubStmt(SubStmt); 243} 244 245StmtResult 246Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 247 Stmt *SubStmt, Scope *CurScope) { 248 if (getCurFunction()->SwitchStack.empty()) { 249 Diag(DefaultLoc, diag::err_default_not_in_switch); 250 return Owned(SubStmt); 251 } 252 253 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 254 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 255 return Owned(DS); 256} 257 258StmtResult 259Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 260 SourceLocation ColonLoc, Stmt *SubStmt) { 261 262 // If the label was multiply defined, reject it now. 263 if (TheDecl->getStmt()) { 264 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 265 Diag(TheDecl->getLocation(), diag::note_previous_definition); 266 return Owned(SubStmt); 267 } 268 269 // Otherwise, things are good. Fill in the declaration and return it. 270 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 271 TheDecl->setStmt(LS); 272 if (!TheDecl->isGnuLocal()) 273 TheDecl->setLocation(IdentLoc); 274 return Owned(LS); 275} 276 277StmtResult 278Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 279 Stmt *thenStmt, SourceLocation ElseLoc, 280 Stmt *elseStmt) { 281 ExprResult CondResult(CondVal.release()); 282 283 VarDecl *ConditionVar = 0; 284 if (CondVar) { 285 ConditionVar = cast<VarDecl>(CondVar); 286 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 287 if (CondResult.isInvalid()) 288 return StmtError(); 289 } 290 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 291 if (!ConditionExpr) 292 return StmtError(); 293 294 DiagnoseUnusedExprResult(thenStmt); 295 296 // Warn if the if block has a null body without an else value. 297 // this helps prevent bugs due to typos, such as 298 // if (condition); 299 // do_stuff(); 300 // 301 if (!elseStmt) { 302 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 303 // But do not warn if the body is a macro that expands to nothing, e.g: 304 // 305 // #define CALL(x) 306 // if (condition) 307 // CALL(0); 308 // 309 if (!stmt->hasLeadingEmptyMacro()) 310 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 311 } 312 313 DiagnoseUnusedExprResult(elseStmt); 314 315 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 316 thenStmt, ElseLoc, elseStmt)); 317} 318 319/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 320/// the specified width and sign. If an overflow occurs, detect it and emit 321/// the specified diagnostic. 322void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 323 unsigned NewWidth, bool NewSign, 324 SourceLocation Loc, 325 unsigned DiagID) { 326 // Perform a conversion to the promoted condition type if needed. 327 if (NewWidth > Val.getBitWidth()) { 328 // If this is an extension, just do it. 329 Val = Val.extend(NewWidth); 330 Val.setIsSigned(NewSign); 331 332 // If the input was signed and negative and the output is 333 // unsigned, don't bother to warn: this is implementation-defined 334 // behavior. 335 // FIXME: Introduce a second, default-ignored warning for this case? 336 } else if (NewWidth < Val.getBitWidth()) { 337 // If this is a truncation, check for overflow. 338 llvm::APSInt ConvVal(Val); 339 ConvVal = ConvVal.trunc(NewWidth); 340 ConvVal.setIsSigned(NewSign); 341 ConvVal = ConvVal.extend(Val.getBitWidth()); 342 ConvVal.setIsSigned(Val.isSigned()); 343 if (ConvVal != Val) 344 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 345 346 // Regardless of whether a diagnostic was emitted, really do the 347 // truncation. 348 Val = Val.trunc(NewWidth); 349 Val.setIsSigned(NewSign); 350 } else if (NewSign != Val.isSigned()) { 351 // Convert the sign to match the sign of the condition. This can cause 352 // overflow as well: unsigned(INTMIN) 353 // We don't diagnose this overflow, because it is implementation-defined 354 // behavior. 355 // FIXME: Introduce a second, default-ignored warning for this case? 356 llvm::APSInt OldVal(Val); 357 Val.setIsSigned(NewSign); 358 } 359} 360 361namespace { 362 struct CaseCompareFunctor { 363 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 364 const llvm::APSInt &RHS) { 365 return LHS.first < RHS; 366 } 367 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 368 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 369 return LHS.first < RHS.first; 370 } 371 bool operator()(const llvm::APSInt &LHS, 372 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 373 return LHS < RHS.first; 374 } 375 }; 376} 377 378/// CmpCaseVals - Comparison predicate for sorting case values. 379/// 380static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 381 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 382 if (lhs.first < rhs.first) 383 return true; 384 385 if (lhs.first == rhs.first && 386 lhs.second->getCaseLoc().getRawEncoding() 387 < rhs.second->getCaseLoc().getRawEncoding()) 388 return true; 389 return false; 390} 391 392/// CmpEnumVals - Comparison predicate for sorting enumeration values. 393/// 394static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 395 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 396{ 397 return lhs.first < rhs.first; 398} 399 400/// EqEnumVals - Comparison preficate for uniqing enumeration values. 401/// 402static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 403 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 404{ 405 return lhs.first == rhs.first; 406} 407 408/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 409/// potentially integral-promoted expression @p expr. 410static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 411 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 412 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 413 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 414 if (TypeBeforePromotion->isIntegralOrEnumerationType()) { 415 return TypeBeforePromotion; 416 } 417 } 418 return expr->getType(); 419} 420 421StmtResult 422Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 423 Decl *CondVar) { 424 ExprResult CondResult; 425 426 VarDecl *ConditionVar = 0; 427 if (CondVar) { 428 ConditionVar = cast<VarDecl>(CondVar); 429 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 430 if (CondResult.isInvalid()) 431 return StmtError(); 432 433 Cond = CondResult.release(); 434 } 435 436 if (!Cond) 437 return StmtError(); 438 439 CondResult 440 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 441 PDiag(diag::err_typecheck_statement_requires_integer), 442 PDiag(diag::err_switch_incomplete_class_type) 443 << Cond->getSourceRange(), 444 PDiag(diag::err_switch_explicit_conversion), 445 PDiag(diag::note_switch_conversion), 446 PDiag(diag::err_switch_multiple_conversions), 447 PDiag(diag::note_switch_conversion), 448 PDiag(0)); 449 if (CondResult.isInvalid()) return StmtError(); 450 Cond = CondResult.take(); 451 452 if (!CondVar) { 453 CheckImplicitConversions(Cond, SwitchLoc); 454 CondResult = MaybeCreateExprWithCleanups(Cond); 455 if (CondResult.isInvalid()) 456 return StmtError(); 457 Cond = CondResult.take(); 458 } 459 460 getCurFunction()->setHasBranchIntoScope(); 461 462 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 463 getCurFunction()->SwitchStack.push_back(SS); 464 return Owned(SS); 465} 466 467static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 468 if (Val.getBitWidth() < BitWidth) 469 Val = Val.extend(BitWidth); 470 else if (Val.getBitWidth() > BitWidth) 471 Val = Val.trunc(BitWidth); 472 Val.setIsSigned(IsSigned); 473} 474 475StmtResult 476Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 477 Stmt *BodyStmt) { 478 SwitchStmt *SS = cast<SwitchStmt>(Switch); 479 assert(SS == getCurFunction()->SwitchStack.back() && 480 "switch stack missing push/pop!"); 481 482 SS->setBody(BodyStmt, SwitchLoc); 483 getCurFunction()->SwitchStack.pop_back(); 484 485 if (SS->getCond() == 0) 486 return StmtError(); 487 488 Expr *CondExpr = SS->getCond(); 489 Expr *CondExprBeforePromotion = CondExpr; 490 QualType CondTypeBeforePromotion = 491 GetTypeBeforeIntegralPromotion(CondExpr); 492 493 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 494 ExprResult CondResult = UsualUnaryConversions(CondExpr); 495 if (CondResult.isInvalid()) 496 return StmtError(); 497 CondExpr = CondResult.take(); 498 QualType CondType = CondExpr->getType(); 499 SS->setCond(CondExpr); 500 501 // C++ 6.4.2.p2: 502 // Integral promotions are performed (on the switch condition). 503 // 504 // A case value unrepresentable by the original switch condition 505 // type (before the promotion) doesn't make sense, even when it can 506 // be represented by the promoted type. Therefore we need to find 507 // the pre-promotion type of the switch condition. 508 if (!CondExpr->isTypeDependent()) { 509 // We have already converted the expression to an integral or enumeration 510 // type, when we started the switch statement. If we don't have an 511 // appropriate type now, just return an error. 512 if (!CondType->isIntegralOrEnumerationType()) 513 return StmtError(); 514 515 if (CondExpr->isKnownToHaveBooleanValue()) { 516 // switch(bool_expr) {...} is often a programmer error, e.g. 517 // switch(n && mask) { ... } // Doh - should be "n & mask". 518 // One can always use an if statement instead of switch(bool_expr). 519 Diag(SwitchLoc, diag::warn_bool_switch_condition) 520 << CondExpr->getSourceRange(); 521 } 522 } 523 524 // Get the bitwidth of the switched-on value before promotions. We must 525 // convert the integer case values to this width before comparison. 526 bool HasDependentValue 527 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 528 unsigned CondWidth 529 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 530 bool CondIsSigned 531 = CondTypeBeforePromotion->isSignedIntegerOrEnumerationType(); 532 533 // Accumulate all of the case values in a vector so that we can sort them 534 // and detect duplicates. This vector contains the APInt for the case after 535 // it has been converted to the condition type. 536 typedef SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 537 CaseValsTy CaseVals; 538 539 // Keep track of any GNU case ranges we see. The APSInt is the low value. 540 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 541 CaseRangesTy CaseRanges; 542 543 DefaultStmt *TheDefaultStmt = 0; 544 545 bool CaseListIsErroneous = false; 546 547 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 548 SC = SC->getNextSwitchCase()) { 549 550 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 551 if (TheDefaultStmt) { 552 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 553 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 554 555 // FIXME: Remove the default statement from the switch block so that 556 // we'll return a valid AST. This requires recursing down the AST and 557 // finding it, not something we are set up to do right now. For now, 558 // just lop the entire switch stmt out of the AST. 559 CaseListIsErroneous = true; 560 } 561 TheDefaultStmt = DS; 562 563 } else { 564 CaseStmt *CS = cast<CaseStmt>(SC); 565 566 // We already verified that the expression has a i-c-e value (C99 567 // 6.8.4.2p3) - get that value now. 568 Expr *Lo = CS->getLHS(); 569 570 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 571 HasDependentValue = true; 572 break; 573 } 574 575 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 576 577 // Convert the value to the same width/sign as the condition. 578 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 579 Lo->getLocStart(), 580 diag::warn_case_value_overflow); 581 582 // If the LHS is not the same type as the condition, insert an implicit 583 // cast. 584 Lo = ImpCastExprToType(Lo, CondType, CK_IntegralCast).take(); 585 CS->setLHS(Lo); 586 587 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 588 if (CS->getRHS()) { 589 if (CS->getRHS()->isTypeDependent() || 590 CS->getRHS()->isValueDependent()) { 591 HasDependentValue = true; 592 break; 593 } 594 CaseRanges.push_back(std::make_pair(LoVal, CS)); 595 } else 596 CaseVals.push_back(std::make_pair(LoVal, CS)); 597 } 598 } 599 600 if (!HasDependentValue) { 601 // If we don't have a default statement, check whether the 602 // condition is constant. 603 llvm::APSInt ConstantCondValue; 604 bool HasConstantCond = false; 605 bool ShouldCheckConstantCond = false; 606 if (!HasDependentValue && !TheDefaultStmt) { 607 Expr::EvalResult Result; 608 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 609 if (HasConstantCond) { 610 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 611 ConstantCondValue = Result.Val.getInt(); 612 ShouldCheckConstantCond = true; 613 614 assert(ConstantCondValue.getBitWidth() == CondWidth && 615 ConstantCondValue.isSigned() == CondIsSigned); 616 } 617 } 618 619 // Sort all the scalar case values so we can easily detect duplicates. 620 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 621 622 if (!CaseVals.empty()) { 623 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 624 if (ShouldCheckConstantCond && 625 CaseVals[i].first == ConstantCondValue) 626 ShouldCheckConstantCond = false; 627 628 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 629 // If we have a duplicate, report it. 630 Diag(CaseVals[i].second->getLHS()->getLocStart(), 631 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 632 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 633 diag::note_duplicate_case_prev); 634 // FIXME: We really want to remove the bogus case stmt from the 635 // substmt, but we have no way to do this right now. 636 CaseListIsErroneous = true; 637 } 638 } 639 } 640 641 // Detect duplicate case ranges, which usually don't exist at all in 642 // the first place. 643 if (!CaseRanges.empty()) { 644 // Sort all the case ranges by their low value so we can easily detect 645 // overlaps between ranges. 646 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 647 648 // Scan the ranges, computing the high values and removing empty ranges. 649 std::vector<llvm::APSInt> HiVals; 650 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 651 llvm::APSInt &LoVal = CaseRanges[i].first; 652 CaseStmt *CR = CaseRanges[i].second; 653 Expr *Hi = CR->getRHS(); 654 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 655 656 // Convert the value to the same width/sign as the condition. 657 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 658 Hi->getLocStart(), 659 diag::warn_case_value_overflow); 660 661 // If the LHS is not the same type as the condition, insert an implicit 662 // cast. 663 Hi = ImpCastExprToType(Hi, CondType, CK_IntegralCast).take(); 664 CR->setRHS(Hi); 665 666 // If the low value is bigger than the high value, the case is empty. 667 if (LoVal > HiVal) { 668 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 669 << SourceRange(CR->getLHS()->getLocStart(), 670 Hi->getLocEnd()); 671 CaseRanges.erase(CaseRanges.begin()+i); 672 --i, --e; 673 continue; 674 } 675 676 if (ShouldCheckConstantCond && 677 LoVal <= ConstantCondValue && 678 ConstantCondValue <= HiVal) 679 ShouldCheckConstantCond = false; 680 681 HiVals.push_back(HiVal); 682 } 683 684 // Rescan the ranges, looking for overlap with singleton values and other 685 // ranges. Since the range list is sorted, we only need to compare case 686 // ranges with their neighbors. 687 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 688 llvm::APSInt &CRLo = CaseRanges[i].first; 689 llvm::APSInt &CRHi = HiVals[i]; 690 CaseStmt *CR = CaseRanges[i].second; 691 692 // Check to see whether the case range overlaps with any 693 // singleton cases. 694 CaseStmt *OverlapStmt = 0; 695 llvm::APSInt OverlapVal(32); 696 697 // Find the smallest value >= the lower bound. If I is in the 698 // case range, then we have overlap. 699 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 700 CaseVals.end(), CRLo, 701 CaseCompareFunctor()); 702 if (I != CaseVals.end() && I->first < CRHi) { 703 OverlapVal = I->first; // Found overlap with scalar. 704 OverlapStmt = I->second; 705 } 706 707 // Find the smallest value bigger than the upper bound. 708 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 709 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 710 OverlapVal = (I-1)->first; // Found overlap with scalar. 711 OverlapStmt = (I-1)->second; 712 } 713 714 // Check to see if this case stmt overlaps with the subsequent 715 // case range. 716 if (i && CRLo <= HiVals[i-1]) { 717 OverlapVal = HiVals[i-1]; // Found overlap with range. 718 OverlapStmt = CaseRanges[i-1].second; 719 } 720 721 if (OverlapStmt) { 722 // If we have a duplicate, report it. 723 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 724 << OverlapVal.toString(10); 725 Diag(OverlapStmt->getLHS()->getLocStart(), 726 diag::note_duplicate_case_prev); 727 // FIXME: We really want to remove the bogus case stmt from the 728 // substmt, but we have no way to do this right now. 729 CaseListIsErroneous = true; 730 } 731 } 732 } 733 734 // Complain if we have a constant condition and we didn't find a match. 735 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 736 // TODO: it would be nice if we printed enums as enums, chars as 737 // chars, etc. 738 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 739 << ConstantCondValue.toString(10) 740 << CondExpr->getSourceRange(); 741 } 742 743 // Check to see if switch is over an Enum and handles all of its 744 // values. We only issue a warning if there is not 'default:', but 745 // we still do the analysis to preserve this information in the AST 746 // (which can be used by flow-based analyes). 747 // 748 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 749 750 // If switch has default case, then ignore it. 751 if (!CaseListIsErroneous && !HasConstantCond && ET) { 752 const EnumDecl *ED = ET->getDecl(); 753 typedef SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> 754 EnumValsTy; 755 EnumValsTy EnumVals; 756 757 // Gather all enum values, set their type and sort them, 758 // allowing easier comparison with CaseVals. 759 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 760 EDI != ED->enumerator_end(); ++EDI) { 761 llvm::APSInt Val = EDI->getInitVal(); 762 AdjustAPSInt(Val, CondWidth, CondIsSigned); 763 EnumVals.push_back(std::make_pair(Val, *EDI)); 764 } 765 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 766 EnumValsTy::iterator EIend = 767 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 768 769 // See which case values aren't in enum. 770 // TODO: we might want to check whether case values are out of the 771 // enum even if we don't want to check whether all cases are handled. 772 if (!TheDefaultStmt) { 773 EnumValsTy::const_iterator EI = EnumVals.begin(); 774 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 775 CI != CaseVals.end(); CI++) { 776 while (EI != EIend && EI->first < CI->first) 777 EI++; 778 if (EI == EIend || EI->first > CI->first) 779 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 780 << ED->getDeclName(); 781 } 782 // See which of case ranges aren't in enum 783 EI = EnumVals.begin(); 784 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 785 RI != CaseRanges.end() && EI != EIend; RI++) { 786 while (EI != EIend && EI->first < RI->first) 787 EI++; 788 789 if (EI == EIend || EI->first != RI->first) { 790 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 791 << ED->getDeclName(); 792 } 793 794 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 795 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 796 while (EI != EIend && EI->first < Hi) 797 EI++; 798 if (EI == EIend || EI->first != Hi) 799 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 800 << ED->getDeclName(); 801 } 802 } 803 804 // Check which enum vals aren't in switch 805 CaseValsTy::const_iterator CI = CaseVals.begin(); 806 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 807 bool hasCasesNotInSwitch = false; 808 809 SmallVector<DeclarationName,8> UnhandledNames; 810 811 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 812 // Drop unneeded case values 813 llvm::APSInt CIVal; 814 while (CI != CaseVals.end() && CI->first < EI->first) 815 CI++; 816 817 if (CI != CaseVals.end() && CI->first == EI->first) 818 continue; 819 820 // Drop unneeded case ranges 821 for (; RI != CaseRanges.end(); RI++) { 822 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 823 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 824 if (EI->first <= Hi) 825 break; 826 } 827 828 if (RI == CaseRanges.end() || EI->first < RI->first) { 829 hasCasesNotInSwitch = true; 830 if (!TheDefaultStmt) 831 UnhandledNames.push_back(EI->second->getDeclName()); 832 } 833 } 834 835 // Produce a nice diagnostic if multiple values aren't handled. 836 switch (UnhandledNames.size()) { 837 case 0: break; 838 case 1: 839 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 840 << UnhandledNames[0]; 841 break; 842 case 2: 843 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 844 << UnhandledNames[0] << UnhandledNames[1]; 845 break; 846 case 3: 847 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 848 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 849 break; 850 default: 851 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 852 << (unsigned)UnhandledNames.size() 853 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 854 break; 855 } 856 857 if (!hasCasesNotInSwitch) 858 SS->setAllEnumCasesCovered(); 859 } 860 } 861 862 // FIXME: If the case list was broken is some way, we don't have a good system 863 // to patch it up. Instead, just return the whole substmt as broken. 864 if (CaseListIsErroneous) 865 return StmtError(); 866 867 return Owned(SS); 868} 869 870StmtResult 871Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 872 Decl *CondVar, Stmt *Body) { 873 ExprResult CondResult(Cond.release()); 874 875 VarDecl *ConditionVar = 0; 876 if (CondVar) { 877 ConditionVar = cast<VarDecl>(CondVar); 878 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 879 if (CondResult.isInvalid()) 880 return StmtError(); 881 } 882 Expr *ConditionExpr = CondResult.take(); 883 if (!ConditionExpr) 884 return StmtError(); 885 886 DiagnoseUnusedExprResult(Body); 887 888 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 889 Body, WhileLoc)); 890} 891 892StmtResult 893Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 894 SourceLocation WhileLoc, SourceLocation CondLParen, 895 Expr *Cond, SourceLocation CondRParen) { 896 assert(Cond && "ActOnDoStmt(): missing expression"); 897 898 ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc); 899 if (CondResult.isInvalid() || CondResult.isInvalid()) 900 return StmtError(); 901 Cond = CondResult.take(); 902 903 CheckImplicitConversions(Cond, DoLoc); 904 CondResult = MaybeCreateExprWithCleanups(Cond); 905 if (CondResult.isInvalid()) 906 return StmtError(); 907 Cond = CondResult.take(); 908 909 DiagnoseUnusedExprResult(Body); 910 911 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 912} 913 914StmtResult 915Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 916 Stmt *First, FullExprArg second, Decl *secondVar, 917 FullExprArg third, 918 SourceLocation RParenLoc, Stmt *Body) { 919 if (!getLangOptions().CPlusPlus) { 920 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 921 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 922 // declare identifiers for objects having storage class 'auto' or 923 // 'register'. 924 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 925 DI!=DE; ++DI) { 926 VarDecl *VD = dyn_cast<VarDecl>(*DI); 927 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 928 VD = 0; 929 if (VD == 0) 930 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 931 // FIXME: mark decl erroneous! 932 } 933 } 934 } 935 936 ExprResult SecondResult(second.release()); 937 VarDecl *ConditionVar = 0; 938 if (secondVar) { 939 ConditionVar = cast<VarDecl>(secondVar); 940 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 941 if (SecondResult.isInvalid()) 942 return StmtError(); 943 } 944 945 Expr *Third = third.release().takeAs<Expr>(); 946 947 DiagnoseUnusedExprResult(First); 948 DiagnoseUnusedExprResult(Third); 949 DiagnoseUnusedExprResult(Body); 950 951 return Owned(new (Context) ForStmt(Context, First, 952 SecondResult.take(), ConditionVar, 953 Third, Body, ForLoc, LParenLoc, 954 RParenLoc)); 955} 956 957/// In an Objective C collection iteration statement: 958/// for (x in y) 959/// x can be an arbitrary l-value expression. Bind it up as a 960/// full-expression. 961StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 962 CheckImplicitConversions(E); 963 ExprResult Result = MaybeCreateExprWithCleanups(E); 964 if (Result.isInvalid()) return StmtError(); 965 return Owned(static_cast<Stmt*>(Result.get())); 966} 967 968ExprResult 969Sema::ActOnObjCForCollectionOperand(SourceLocation forLoc, Expr *collection) { 970 assert(collection); 971 972 // Bail out early if we've got a type-dependent expression. 973 if (collection->isTypeDependent()) return Owned(collection); 974 975 // Perform normal l-value conversion. 976 ExprResult result = DefaultFunctionArrayLvalueConversion(collection); 977 if (result.isInvalid()) 978 return ExprError(); 979 collection = result.take(); 980 981 // The operand needs to have object-pointer type. 982 // TODO: should we do a contextual conversion? 983 const ObjCObjectPointerType *pointerType = 984 collection->getType()->getAs<ObjCObjectPointerType>(); 985 if (!pointerType) 986 return Diag(forLoc, diag::err_collection_expr_type) 987 << collection->getType() << collection->getSourceRange(); 988 989 // Check that the operand provides 990 // - countByEnumeratingWithState:objects:count: 991 const ObjCObjectType *objectType = pointerType->getObjectType(); 992 ObjCInterfaceDecl *iface = objectType->getInterface(); 993 994 // If we have a forward-declared type, we can't do this check. 995 if (iface && iface->isForwardDecl()) { 996 // This is ill-formed under ARC. 997 if (getLangOptions().ObjCAutoRefCount) { 998 Diag(forLoc, diag::err_arc_collection_forward) 999 << pointerType->getPointeeType() << collection->getSourceRange(); 1000 } 1001 1002 // Otherwise, if we have any useful type information, check that 1003 // the type declares the appropriate method. 1004 } else if (iface || !objectType->qual_empty()) { 1005 IdentifierInfo *selectorIdents[] = { 1006 &Context.Idents.get("countByEnumeratingWithState"), 1007 &Context.Idents.get("objects"), 1008 &Context.Idents.get("count") 1009 }; 1010 Selector selector = Context.Selectors.getSelector(3, &selectorIdents[0]); 1011 1012 ObjCMethodDecl *method = 0; 1013 1014 // If there's an interface, look in both the public and private APIs. 1015 if (iface) { 1016 method = iface->lookupInstanceMethod(selector); 1017 if (!method) method = LookupPrivateInstanceMethod(selector, iface); 1018 } 1019 1020 // Also check protocol qualifiers. 1021 if (!method) 1022 method = LookupMethodInQualifiedType(selector, pointerType, 1023 /*instance*/ true); 1024 1025 // If we didn't find it anywhere, give up. 1026 if (!method) { 1027 Diag(forLoc, diag::warn_collection_expr_type) 1028 << collection->getType() << selector << collection->getSourceRange(); 1029 } 1030 1031 // TODO: check for an incompatible signature? 1032 } 1033 1034 // Wrap up any cleanups in the expression. 1035 return Owned(MaybeCreateExprWithCleanups(collection)); 1036} 1037 1038StmtResult 1039Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 1040 SourceLocation LParenLoc, 1041 Stmt *First, Expr *Second, 1042 SourceLocation RParenLoc, Stmt *Body) { 1043 if (First) { 1044 QualType FirstType; 1045 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 1046 if (!DS->isSingleDecl()) 1047 return StmtError(Diag((*DS->decl_begin())->getLocation(), 1048 diag::err_toomany_element_decls)); 1049 1050 VarDecl *D = cast<VarDecl>(DS->getSingleDecl()); 1051 FirstType = D->getType(); 1052 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 1053 // declare identifiers for objects having storage class 'auto' or 1054 // 'register'. 1055 if (!D->hasLocalStorage()) 1056 return StmtError(Diag(D->getLocation(), 1057 diag::err_non_variable_decl_in_for)); 1058 } else { 1059 Expr *FirstE = cast<Expr>(First); 1060 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 1061 return StmtError(Diag(First->getLocStart(), 1062 diag::err_selector_element_not_lvalue) 1063 << First->getSourceRange()); 1064 1065 FirstType = static_cast<Expr*>(First)->getType(); 1066 } 1067 if (!FirstType->isDependentType() && 1068 !FirstType->isObjCObjectPointerType() && 1069 !FirstType->isBlockPointerType()) 1070 Diag(ForLoc, diag::err_selector_element_type) 1071 << FirstType << First->getSourceRange(); 1072 } 1073 1074 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1075 ForLoc, RParenLoc)); 1076} 1077 1078namespace { 1079 1080enum BeginEndFunction { 1081 BEF_begin, 1082 BEF_end 1083}; 1084 1085/// Build a variable declaration for a for-range statement. 1086static VarDecl *BuildForRangeVarDecl(Sema &SemaRef, SourceLocation Loc, 1087 QualType Type, const char *Name) { 1088 DeclContext *DC = SemaRef.CurContext; 1089 IdentifierInfo *II = &SemaRef.PP.getIdentifierTable().get(Name); 1090 TypeSourceInfo *TInfo = SemaRef.Context.getTrivialTypeSourceInfo(Type, Loc); 1091 VarDecl *Decl = VarDecl::Create(SemaRef.Context, DC, Loc, Loc, II, Type, 1092 TInfo, SC_Auto, SC_None); 1093 Decl->setImplicit(); 1094 return Decl; 1095} 1096 1097/// Finish building a variable declaration for a for-range statement. 1098/// \return true if an error occurs. 1099static bool FinishForRangeVarDecl(Sema &SemaRef, VarDecl *Decl, Expr *Init, 1100 SourceLocation Loc, int diag) { 1101 // Deduce the type for the iterator variable now rather than leaving it to 1102 // AddInitializerToDecl, so we can produce a more suitable diagnostic. 1103 TypeSourceInfo *InitTSI = 0; 1104 if (Init->getType()->isVoidType() || 1105 !SemaRef.DeduceAutoType(Decl->getTypeSourceInfo(), Init, InitTSI)) 1106 SemaRef.Diag(Loc, diag) << Init->getType(); 1107 if (!InitTSI) { 1108 Decl->setInvalidDecl(); 1109 return true; 1110 } 1111 Decl->setTypeSourceInfo(InitTSI); 1112 Decl->setType(InitTSI->getType()); 1113 1114 // In ARC, infer lifetime. 1115 // FIXME: ARC may want to turn this into 'const __unsafe_unretained' if 1116 // we're doing the equivalent of fast iteration. 1117 if (SemaRef.getLangOptions().ObjCAutoRefCount && 1118 SemaRef.inferObjCARCLifetime(Decl)) 1119 Decl->setInvalidDecl(); 1120 1121 SemaRef.AddInitializerToDecl(Decl, Init, /*DirectInit=*/false, 1122 /*TypeMayContainAuto=*/false); 1123 SemaRef.FinalizeDeclaration(Decl); 1124 SemaRef.CurContext->addHiddenDecl(Decl); 1125 return false; 1126} 1127 1128/// Produce a note indicating which begin/end function was implicitly called 1129/// by a C++0x for-range statement. This is often not obvious from the code, 1130/// nor from the diagnostics produced when analysing the implicit expressions 1131/// required in a for-range statement. 1132void NoteForRangeBeginEndFunction(Sema &SemaRef, Expr *E, 1133 BeginEndFunction BEF) { 1134 CallExpr *CE = dyn_cast<CallExpr>(E); 1135 if (!CE) 1136 return; 1137 FunctionDecl *D = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); 1138 if (!D) 1139 return; 1140 SourceLocation Loc = D->getLocation(); 1141 1142 std::string Description; 1143 bool IsTemplate = false; 1144 if (FunctionTemplateDecl *FunTmpl = D->getPrimaryTemplate()) { 1145 Description = SemaRef.getTemplateArgumentBindingsText( 1146 FunTmpl->getTemplateParameters(), *D->getTemplateSpecializationArgs()); 1147 IsTemplate = true; 1148 } 1149 1150 SemaRef.Diag(Loc, diag::note_for_range_begin_end) 1151 << BEF << IsTemplate << Description << E->getType(); 1152} 1153 1154/// Build a call to 'begin' or 'end' for a C++0x for-range statement. If the 1155/// given LookupResult is non-empty, it is assumed to describe a member which 1156/// will be invoked. Otherwise, the function will be found via argument 1157/// dependent lookup. 1158static ExprResult BuildForRangeBeginEndCall(Sema &SemaRef, Scope *S, 1159 SourceLocation Loc, 1160 VarDecl *Decl, 1161 BeginEndFunction BEF, 1162 const DeclarationNameInfo &NameInfo, 1163 LookupResult &MemberLookup, 1164 Expr *Range) { 1165 ExprResult CallExpr; 1166 if (!MemberLookup.empty()) { 1167 ExprResult MemberRef = 1168 SemaRef.BuildMemberReferenceExpr(Range, Range->getType(), Loc, 1169 /*IsPtr=*/false, CXXScopeSpec(), 1170 /*Qualifier=*/0, MemberLookup, 1171 /*TemplateArgs=*/0); 1172 if (MemberRef.isInvalid()) 1173 return ExprError(); 1174 CallExpr = SemaRef.ActOnCallExpr(S, MemberRef.get(), Loc, MultiExprArg(), 1175 Loc, 0); 1176 if (CallExpr.isInvalid()) 1177 return ExprError(); 1178 } else { 1179 UnresolvedSet<0> FoundNames; 1180 // C++0x [stmt.ranged]p1: For the purposes of this name lookup, namespace 1181 // std is an associated namespace. 1182 UnresolvedLookupExpr *Fn = 1183 UnresolvedLookupExpr::Create(SemaRef.Context, /*NamingClass=*/0, 1184 NestedNameSpecifierLoc(), NameInfo, 1185 /*NeedsADL=*/true, /*Overloaded=*/false, 1186 FoundNames.begin(), FoundNames.end(), 1187 /*LookInStdNamespace=*/true); 1188 CallExpr = SemaRef.BuildOverloadedCallExpr(S, Fn, Fn, Loc, &Range, 1, Loc, 1189 0); 1190 if (CallExpr.isInvalid()) { 1191 SemaRef.Diag(Range->getLocStart(), diag::note_for_range_type) 1192 << Range->getType(); 1193 return ExprError(); 1194 } 1195 } 1196 if (FinishForRangeVarDecl(SemaRef, Decl, CallExpr.get(), Loc, 1197 diag::err_for_range_iter_deduction_failure)) { 1198 NoteForRangeBeginEndFunction(SemaRef, CallExpr.get(), BEF); 1199 return ExprError(); 1200 } 1201 return CallExpr; 1202} 1203 1204} 1205 1206/// ActOnCXXForRangeStmt - Check and build a C++0x for-range statement. 1207/// 1208/// C++0x [stmt.ranged]: 1209/// A range-based for statement is equivalent to 1210/// 1211/// { 1212/// auto && __range = range-init; 1213/// for ( auto __begin = begin-expr, 1214/// __end = end-expr; 1215/// __begin != __end; 1216/// ++__begin ) { 1217/// for-range-declaration = *__begin; 1218/// statement 1219/// } 1220/// } 1221/// 1222/// The body of the loop is not available yet, since it cannot be analysed until 1223/// we have determined the type of the for-range-declaration. 1224StmtResult 1225Sema::ActOnCXXForRangeStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 1226 Stmt *First, SourceLocation ColonLoc, Expr *Range, 1227 SourceLocation RParenLoc) { 1228 if (!First || !Range) 1229 return StmtError(); 1230 1231 DeclStmt *DS = dyn_cast<DeclStmt>(First); 1232 assert(DS && "first part of for range not a decl stmt"); 1233 1234 if (!DS->isSingleDecl()) { 1235 Diag(DS->getStartLoc(), diag::err_type_defined_in_for_range); 1236 return StmtError(); 1237 } 1238 if (DS->getSingleDecl()->isInvalidDecl()) 1239 return StmtError(); 1240 1241 if (DiagnoseUnexpandedParameterPack(Range, UPPC_Expression)) 1242 return StmtError(); 1243 1244 // Build auto && __range = range-init 1245 SourceLocation RangeLoc = Range->getLocStart(); 1246 VarDecl *RangeVar = BuildForRangeVarDecl(*this, RangeLoc, 1247 Context.getAutoRRefDeductType(), 1248 "__range"); 1249 if (FinishForRangeVarDecl(*this, RangeVar, Range, RangeLoc, 1250 diag::err_for_range_deduction_failure)) 1251 return StmtError(); 1252 1253 // Claim the type doesn't contain auto: we've already done the checking. 1254 DeclGroupPtrTy RangeGroup = 1255 BuildDeclaratorGroup((Decl**)&RangeVar, 1, /*TypeMayContainAuto=*/false); 1256 StmtResult RangeDecl = ActOnDeclStmt(RangeGroup, RangeLoc, RangeLoc); 1257 if (RangeDecl.isInvalid()) 1258 return StmtError(); 1259 1260 return BuildCXXForRangeStmt(ForLoc, ColonLoc, RangeDecl.get(), 1261 /*BeginEndDecl=*/0, /*Cond=*/0, /*Inc=*/0, DS, 1262 RParenLoc); 1263} 1264 1265/// BuildCXXForRangeStmt - Build or instantiate a C++0x for-range statement. 1266StmtResult 1267Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation ColonLoc, 1268 Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond, 1269 Expr *Inc, Stmt *LoopVarDecl, 1270 SourceLocation RParenLoc) { 1271 Scope *S = getCurScope(); 1272 1273 DeclStmt *RangeDS = cast<DeclStmt>(RangeDecl); 1274 VarDecl *RangeVar = cast<VarDecl>(RangeDS->getSingleDecl()); 1275 QualType RangeVarType = RangeVar->getType(); 1276 1277 DeclStmt *LoopVarDS = cast<DeclStmt>(LoopVarDecl); 1278 VarDecl *LoopVar = cast<VarDecl>(LoopVarDS->getSingleDecl()); 1279 1280 StmtResult BeginEndDecl = BeginEnd; 1281 ExprResult NotEqExpr = Cond, IncrExpr = Inc; 1282 1283 if (!BeginEndDecl.get() && !RangeVarType->isDependentType()) { 1284 SourceLocation RangeLoc = RangeVar->getLocation(); 1285 1286 ExprResult RangeRef = BuildDeclRefExpr(RangeVar, 1287 RangeVarType.getNonReferenceType(), 1288 VK_LValue, ColonLoc); 1289 if (RangeRef.isInvalid()) 1290 return StmtError(); 1291 1292 QualType AutoType = Context.getAutoDeductType(); 1293 Expr *Range = RangeVar->getInit(); 1294 if (!Range) 1295 return StmtError(); 1296 QualType RangeType = Range->getType(); 1297 1298 if (RequireCompleteType(RangeLoc, RangeType, 1299 PDiag(diag::err_for_range_incomplete_type))) 1300 return StmtError(); 1301 1302 // Build auto __begin = begin-expr, __end = end-expr. 1303 VarDecl *BeginVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1304 "__begin"); 1305 VarDecl *EndVar = BuildForRangeVarDecl(*this, ColonLoc, AutoType, 1306 "__end"); 1307 1308 // Build begin-expr and end-expr and attach to __begin and __end variables. 1309 ExprResult BeginExpr, EndExpr; 1310 if (const ArrayType *UnqAT = RangeType->getAsArrayTypeUnsafe()) { 1311 // - if _RangeT is an array type, begin-expr and end-expr are __range and 1312 // __range + __bound, respectively, where __bound is the array bound. If 1313 // _RangeT is an array of unknown size or an array of incomplete type, 1314 // the program is ill-formed; 1315 1316 // begin-expr is __range. 1317 BeginExpr = RangeRef; 1318 if (FinishForRangeVarDecl(*this, BeginVar, RangeRef.get(), ColonLoc, 1319 diag::err_for_range_iter_deduction_failure)) { 1320 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1321 return StmtError(); 1322 } 1323 1324 // Find the array bound. 1325 ExprResult BoundExpr; 1326 if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(UnqAT)) 1327 BoundExpr = Owned(IntegerLiteral::Create(Context, CAT->getSize(), 1328 Context.getPointerDiffType(), 1329 RangeLoc)); 1330 else if (const VariableArrayType *VAT = 1331 dyn_cast<VariableArrayType>(UnqAT)) 1332 BoundExpr = VAT->getSizeExpr(); 1333 else { 1334 // Can't be a DependentSizedArrayType or an IncompleteArrayType since 1335 // UnqAT is not incomplete and Range is not type-dependent. 1336 assert(0 && "Unexpected array type in for-range"); 1337 return StmtError(); 1338 } 1339 1340 // end-expr is __range + __bound. 1341 EndExpr = ActOnBinOp(S, ColonLoc, tok::plus, RangeRef.get(), 1342 BoundExpr.get()); 1343 if (EndExpr.isInvalid()) 1344 return StmtError(); 1345 if (FinishForRangeVarDecl(*this, EndVar, EndExpr.get(), ColonLoc, 1346 diag::err_for_range_iter_deduction_failure)) { 1347 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1348 return StmtError(); 1349 } 1350 } else { 1351 DeclarationNameInfo BeginNameInfo(&PP.getIdentifierTable().get("begin"), 1352 ColonLoc); 1353 DeclarationNameInfo EndNameInfo(&PP.getIdentifierTable().get("end"), 1354 ColonLoc); 1355 1356 LookupResult BeginMemberLookup(*this, BeginNameInfo, LookupMemberName); 1357 LookupResult EndMemberLookup(*this, EndNameInfo, LookupMemberName); 1358 1359 if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) { 1360 // - if _RangeT is a class type, the unqualified-ids begin and end are 1361 // looked up in the scope of class _RangeT as if by class member access 1362 // lookup (3.4.5), and if either (or both) finds at least one 1363 // declaration, begin-expr and end-expr are __range.begin() and 1364 // __range.end(), respectively; 1365 LookupQualifiedName(BeginMemberLookup, D); 1366 LookupQualifiedName(EndMemberLookup, D); 1367 1368 if (BeginMemberLookup.empty() != EndMemberLookup.empty()) { 1369 Diag(ColonLoc, diag::err_for_range_member_begin_end_mismatch) 1370 << RangeType << BeginMemberLookup.empty(); 1371 return StmtError(); 1372 } 1373 } else { 1374 // - otherwise, begin-expr and end-expr are begin(__range) and 1375 // end(__range), respectively, where begin and end are looked up with 1376 // argument-dependent lookup (3.4.2). For the purposes of this name 1377 // lookup, namespace std is an associated namespace. 1378 } 1379 1380 BeginExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, BeginVar, 1381 BEF_begin, BeginNameInfo, 1382 BeginMemberLookup, RangeRef.get()); 1383 if (BeginExpr.isInvalid()) 1384 return StmtError(); 1385 1386 EndExpr = BuildForRangeBeginEndCall(*this, S, ColonLoc, EndVar, 1387 BEF_end, EndNameInfo, 1388 EndMemberLookup, RangeRef.get()); 1389 if (EndExpr.isInvalid()) 1390 return StmtError(); 1391 } 1392 1393 // C++0x [decl.spec.auto]p6: BeginType and EndType must be the same. 1394 QualType BeginType = BeginVar->getType(), EndType = EndVar->getType(); 1395 if (!Context.hasSameType(BeginType, EndType)) { 1396 Diag(RangeLoc, diag::err_for_range_begin_end_types_differ) 1397 << BeginType << EndType; 1398 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1399 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1400 } 1401 1402 Decl *BeginEndDecls[] = { BeginVar, EndVar }; 1403 // Claim the type doesn't contain auto: we've already done the checking. 1404 DeclGroupPtrTy BeginEndGroup = 1405 BuildDeclaratorGroup(BeginEndDecls, 2, /*TypeMayContainAuto=*/false); 1406 BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc); 1407 1408 ExprResult BeginRef = BuildDeclRefExpr(BeginVar, 1409 BeginType.getNonReferenceType(), 1410 VK_LValue, ColonLoc); 1411 ExprResult EndRef = BuildDeclRefExpr(EndVar, EndType.getNonReferenceType(), 1412 VK_LValue, ColonLoc); 1413 1414 // Build and check __begin != __end expression. 1415 NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal, 1416 BeginRef.get(), EndRef.get()); 1417 NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get()); 1418 NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get()); 1419 if (NotEqExpr.isInvalid()) { 1420 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1421 if (!Context.hasSameType(BeginType, EndType)) 1422 NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end); 1423 return StmtError(); 1424 } 1425 1426 // Build and check ++__begin expression. 1427 IncrExpr = ActOnUnaryOp(S, ColonLoc, tok::plusplus, BeginRef.get()); 1428 IncrExpr = ActOnFinishFullExpr(IncrExpr.get()); 1429 if (IncrExpr.isInvalid()) { 1430 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1431 return StmtError(); 1432 } 1433 1434 // Build and check *__begin expression. 1435 ExprResult DerefExpr = ActOnUnaryOp(S, ColonLoc, tok::star, BeginRef.get()); 1436 if (DerefExpr.isInvalid()) { 1437 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1438 return StmtError(); 1439 } 1440 1441 // Attach *__begin as initializer for VD. 1442 if (!LoopVar->isInvalidDecl()) { 1443 AddInitializerToDecl(LoopVar, DerefExpr.get(), /*DirectInit=*/false, 1444 /*TypeMayContainAuto=*/true); 1445 if (LoopVar->isInvalidDecl()) 1446 NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin); 1447 } 1448 } else { 1449 // The range is implicitly used as a placeholder when it is dependent. 1450 RangeVar->setUsed(); 1451 } 1452 1453 return Owned(new (Context) CXXForRangeStmt(RangeDS, 1454 cast_or_null<DeclStmt>(BeginEndDecl.get()), 1455 NotEqExpr.take(), IncrExpr.take(), 1456 LoopVarDS, /*Body=*/0, ForLoc, 1457 ColonLoc, RParenLoc)); 1458} 1459 1460/// FinishCXXForRangeStmt - Attach the body to a C++0x for-range statement. 1461/// This is a separate step from ActOnCXXForRangeStmt because analysis of the 1462/// body cannot be performed until after the type of the range variable is 1463/// determined. 1464StmtResult Sema::FinishCXXForRangeStmt(Stmt *S, Stmt *B) { 1465 if (!S || !B) 1466 return StmtError(); 1467 1468 cast<CXXForRangeStmt>(S)->setBody(B); 1469 return S; 1470} 1471 1472StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1473 SourceLocation LabelLoc, 1474 LabelDecl *TheDecl) { 1475 getCurFunction()->setHasBranchIntoScope(); 1476 TheDecl->setUsed(); 1477 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1478} 1479 1480StmtResult 1481Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1482 Expr *E) { 1483 // Convert operand to void* 1484 if (!E->isTypeDependent()) { 1485 QualType ETy = E->getType(); 1486 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1487 ExprResult ExprRes = Owned(E); 1488 AssignConvertType ConvTy = 1489 CheckSingleAssignmentConstraints(DestTy, ExprRes); 1490 if (ExprRes.isInvalid()) 1491 return StmtError(); 1492 E = ExprRes.take(); 1493 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1494 return StmtError(); 1495 } 1496 1497 getCurFunction()->setHasIndirectGoto(); 1498 1499 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1500} 1501 1502StmtResult 1503Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1504 Scope *S = CurScope->getContinueParent(); 1505 if (!S) { 1506 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1507 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1508 } 1509 1510 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1511} 1512 1513StmtResult 1514Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1515 Scope *S = CurScope->getBreakParent(); 1516 if (!S) { 1517 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1518 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1519 } 1520 1521 return Owned(new (Context) BreakStmt(BreakLoc)); 1522} 1523 1524/// \brief Determine whether the given expression is a candidate for 1525/// copy elision in either a return statement or a throw expression. 1526/// 1527/// \param ReturnType If we're determining the copy elision candidate for 1528/// a return statement, this is the return type of the function. If we're 1529/// determining the copy elision candidate for a throw expression, this will 1530/// be a NULL type. 1531/// 1532/// \param E The expression being returned from the function or block, or 1533/// being thrown. 1534/// 1535/// \param AllowFunctionParameter Whether we allow function parameters to 1536/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but 1537/// we re-use this logic to determine whether we should try to move as part of 1538/// a return or throw (which does allow function parameters). 1539/// 1540/// \returns The NRVO candidate variable, if the return statement may use the 1541/// NRVO, or NULL if there is no such candidate. 1542const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1543 Expr *E, 1544 bool AllowFunctionParameter) { 1545 QualType ExprType = E->getType(); 1546 // - in a return statement in a function with ... 1547 // ... a class return type ... 1548 if (!ReturnType.isNull()) { 1549 if (!ReturnType->isRecordType()) 1550 return 0; 1551 // ... the same cv-unqualified type as the function return type ... 1552 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1553 return 0; 1554 } 1555 1556 // ... the expression is the name of a non-volatile automatic object 1557 // (other than a function or catch-clause parameter)) ... 1558 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1559 if (!DR) 1560 return 0; 1561 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1562 if (!VD) 1563 return 0; 1564 1565 if (VD->hasLocalStorage() && !VD->isExceptionVariable() && 1566 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1567 !VD->getType().isVolatileQualified() && 1568 ((VD->getKind() == Decl::Var) || 1569 (AllowFunctionParameter && VD->getKind() == Decl::ParmVar))) 1570 return VD; 1571 1572 return 0; 1573} 1574 1575/// \brief Perform the initialization of a potentially-movable value, which 1576/// is the result of return value. 1577/// 1578/// This routine implements C++0x [class.copy]p33, which attempts to treat 1579/// returned lvalues as rvalues in certain cases (to prefer move construction), 1580/// then falls back to treating them as lvalues if that failed. 1581ExprResult 1582Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1583 const VarDecl *NRVOCandidate, 1584 QualType ResultType, 1585 Expr *Value, 1586 bool AllowNRVO) { 1587 // C++0x [class.copy]p33: 1588 // When the criteria for elision of a copy operation are met or would 1589 // be met save for the fact that the source object is a function 1590 // parameter, and the object to be copied is designated by an lvalue, 1591 // overload resolution to select the constructor for the copy is first 1592 // performed as if the object were designated by an rvalue. 1593 ExprResult Res = ExprError(); 1594 if (AllowNRVO && 1595 (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) { 1596 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1597 Value->getType(), CK_LValueToRValue, 1598 Value, VK_XValue); 1599 1600 Expr *InitExpr = &AsRvalue; 1601 InitializationKind Kind 1602 = InitializationKind::CreateCopy(Value->getLocStart(), 1603 Value->getLocStart()); 1604 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1605 1606 // [...] If overload resolution fails, or if the type of the first 1607 // parameter of the selected constructor is not an rvalue reference 1608 // to the object's type (possibly cv-qualified), overload resolution 1609 // is performed again, considering the object as an lvalue. 1610 if (Seq) { 1611 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1612 StepEnd = Seq.step_end(); 1613 Step != StepEnd; ++Step) { 1614 if (Step->Kind != InitializationSequence::SK_ConstructorInitialization) 1615 continue; 1616 1617 CXXConstructorDecl *Constructor 1618 = cast<CXXConstructorDecl>(Step->Function.Function); 1619 1620 const RValueReferenceType *RRefType 1621 = Constructor->getParamDecl(0)->getType() 1622 ->getAs<RValueReferenceType>(); 1623 1624 // If we don't meet the criteria, break out now. 1625 if (!RRefType || 1626 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1627 Context.getTypeDeclType(Constructor->getParent()))) 1628 break; 1629 1630 // Promote "AsRvalue" to the heap, since we now need this 1631 // expression node to persist. 1632 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1633 CK_LValueToRValue, Value, 0, 1634 VK_XValue); 1635 1636 // Complete type-checking the initialization of the return type 1637 // using the constructor we found. 1638 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1639 } 1640 } 1641 } 1642 1643 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1644 // above, or overload resolution failed. Either way, we need to try 1645 // (again) now with the return value expression as written. 1646 if (Res.isInvalid()) 1647 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1648 1649 return Res; 1650} 1651 1652/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1653/// 1654StmtResult 1655Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1656 // If this is the first return we've seen in the block, infer the type of 1657 // the block from it. 1658 BlockScopeInfo *CurBlock = getCurBlock(); 1659 if (CurBlock->ReturnType.isNull()) { 1660 if (RetValExp) { 1661 // Don't call UsualUnaryConversions(), since we don't want to do 1662 // integer promotions here. 1663 ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp); 1664 if (Result.isInvalid()) 1665 return StmtError(); 1666 RetValExp = Result.take(); 1667 1668 if (!RetValExp->isTypeDependent()) { 1669 CurBlock->ReturnType = RetValExp->getType(); 1670 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1671 // We have to remove a 'const' added to copied-in variable which was 1672 // part of the implementation spec. and not the actual qualifier for 1673 // the variable. 1674 if (CDRE->isConstQualAdded()) 1675 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1676 } 1677 } else 1678 CurBlock->ReturnType = Context.DependentTy; 1679 } else 1680 CurBlock->ReturnType = Context.VoidTy; 1681 } 1682 QualType FnRetType = CurBlock->ReturnType; 1683 1684 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1685 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1686 << getCurFunctionOrMethodDecl()->getDeclName(); 1687 return StmtError(); 1688 } 1689 1690 // Otherwise, verify that this result type matches the previous one. We are 1691 // pickier with blocks than for normal functions because we don't have GCC 1692 // compatibility to worry about here. 1693 ReturnStmt *Result = 0; 1694 if (CurBlock->ReturnType->isVoidType()) { 1695 if (RetValExp && !RetValExp->isTypeDependent() && 1696 (!getLangOptions().CPlusPlus || !RetValExp->getType()->isVoidType())) { 1697 Diag(ReturnLoc, diag::err_return_block_has_expr); 1698 RetValExp = 0; 1699 } 1700 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1701 } else if (!RetValExp) { 1702 if (!CurBlock->ReturnType->isDependentType()) 1703 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1704 1705 Result = new (Context) ReturnStmt(ReturnLoc, 0, 0); 1706 } else { 1707 const VarDecl *NRVOCandidate = 0; 1708 1709 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1710 // we have a non-void block with an expression, continue checking 1711 1712 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1713 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1714 // function return. 1715 1716 // In C++ the return statement is handled via a copy initialization. 1717 // the C version of which boils down to CheckSingleAssignmentConstraints. 1718 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1719 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1720 FnRetType, 1721 NRVOCandidate != 0); 1722 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1723 FnRetType, RetValExp); 1724 if (Res.isInvalid()) { 1725 // FIXME: Cleanup temporaries here, anyway? 1726 return StmtError(); 1727 } 1728 1729 if (RetValExp) { 1730 CheckImplicitConversions(RetValExp, ReturnLoc); 1731 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1732 } 1733 1734 RetValExp = Res.takeAs<Expr>(); 1735 if (RetValExp) 1736 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1737 } 1738 1739 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1740 } 1741 1742 // If we need to check for the named return value optimization, save the 1743 // return statement in our scope for later processing. 1744 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1745 !CurContext->isDependentContext()) 1746 FunctionScopes.back()->Returns.push_back(Result); 1747 1748 return Owned(Result); 1749} 1750 1751StmtResult 1752Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1753 // Check for unexpanded parameter packs. 1754 if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp)) 1755 return StmtError(); 1756 1757 if (getCurBlock()) 1758 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1759 1760 QualType FnRetType; 1761 QualType DeclaredRetType; 1762 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1763 FnRetType = FD->getResultType(); 1764 DeclaredRetType = FnRetType; 1765 if (FD->hasAttr<NoReturnAttr>() || 1766 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1767 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1768 << getCurFunctionOrMethodDecl()->getDeclName(); 1769 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) { 1770 DeclaredRetType = MD->getResultType(); 1771 if (MD->hasRelatedResultType() && MD->getClassInterface()) { 1772 // In the implementation of a method with a related return type, the 1773 // type used to type-check the validity of return statements within the 1774 // method body is a pointer to the type of the class being implemented. 1775 FnRetType = Context.getObjCInterfaceType(MD->getClassInterface()); 1776 FnRetType = Context.getObjCObjectPointerType(FnRetType); 1777 } else { 1778 FnRetType = DeclaredRetType; 1779 } 1780 } else // If we don't have a function/method context, bail. 1781 return StmtError(); 1782 1783 ReturnStmt *Result = 0; 1784 if (FnRetType->isVoidType()) { 1785 if (RetValExp) { 1786 if (!RetValExp->isTypeDependent()) { 1787 // C99 6.8.6.4p1 (ext_ since GCC warns) 1788 unsigned D = diag::ext_return_has_expr; 1789 if (RetValExp->getType()->isVoidType()) 1790 D = diag::ext_return_has_void_expr; 1791 else { 1792 ExprResult Result = Owned(RetValExp); 1793 Result = IgnoredValueConversions(Result.take()); 1794 if (Result.isInvalid()) 1795 return StmtError(); 1796 RetValExp = Result.take(); 1797 RetValExp = ImpCastExprToType(RetValExp, 1798 Context.VoidTy, CK_ToVoid).take(); 1799 } 1800 1801 // return (some void expression); is legal in C++. 1802 if (D != diag::ext_return_has_void_expr || 1803 !getLangOptions().CPlusPlus) { 1804 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1805 1806 int FunctionKind = 0; 1807 if (isa<ObjCMethodDecl>(CurDecl)) 1808 FunctionKind = 1; 1809 else if (isa<CXXConstructorDecl>(CurDecl)) 1810 FunctionKind = 2; 1811 else if (isa<CXXDestructorDecl>(CurDecl)) 1812 FunctionKind = 3; 1813 1814 Diag(ReturnLoc, D) 1815 << CurDecl->getDeclName() << FunctionKind 1816 << RetValExp->getSourceRange(); 1817 } 1818 } 1819 1820 CheckImplicitConversions(RetValExp, ReturnLoc); 1821 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1822 } 1823 1824 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1825 } else if (!RetValExp && !FnRetType->isDependentType()) { 1826 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1827 // C99 6.8.6.4p1 (ext_ since GCC warns) 1828 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1829 1830 if (FunctionDecl *FD = getCurFunctionDecl()) 1831 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1832 else 1833 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1834 Result = new (Context) ReturnStmt(ReturnLoc); 1835 } else { 1836 const VarDecl *NRVOCandidate = 0; 1837 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1838 // we have a non-void function with an expression, continue checking 1839 1840 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1841 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1842 // function return. 1843 1844 // In C++ the return statement is handled via a copy initialization, 1845 // the C version of which boils down to CheckSingleAssignmentConstraints. 1846 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1847 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1848 FnRetType, 1849 NRVOCandidate != 0); 1850 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1851 FnRetType, RetValExp); 1852 if (Res.isInvalid()) { 1853 // FIXME: Cleanup temporaries here, anyway? 1854 return StmtError(); 1855 } 1856 1857 RetValExp = Res.takeAs<Expr>(); 1858 if (RetValExp) 1859 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1860 } 1861 1862 if (RetValExp) { 1863 // If we type-checked an Objective-C method's return type based 1864 // on a related return type, we may need to adjust the return 1865 // type again. Do so now. 1866 if (DeclaredRetType != FnRetType) { 1867 ExprResult result = PerformImplicitConversion(RetValExp, 1868 DeclaredRetType, 1869 AA_Returning); 1870 if (result.isInvalid()) return StmtError(); 1871 RetValExp = result.take(); 1872 } 1873 1874 CheckImplicitConversions(RetValExp, ReturnLoc); 1875 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1876 } 1877 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1878 } 1879 1880 // If we need to check for the named return value optimization, save the 1881 // return statement in our scope for later processing. 1882 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1883 !CurContext->isDependentContext()) 1884 FunctionScopes.back()->Returns.push_back(Result); 1885 1886 return Owned(Result); 1887} 1888 1889/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1890/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1891/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1892/// provide a strong guidance to not use it. 1893/// 1894/// This method checks to see if the argument is an acceptable l-value and 1895/// returns false if it is a case we can handle. 1896static bool CheckAsmLValue(const Expr *E, Sema &S) { 1897 // Type dependent expressions will be checked during instantiation. 1898 if (E->isTypeDependent()) 1899 return false; 1900 1901 if (E->isLValue()) 1902 return false; // Cool, this is an lvalue. 1903 1904 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1905 // are supposed to allow. 1906 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1907 if (E != E2 && E2->isLValue()) { 1908 if (!S.getLangOptions().HeinousExtensions) 1909 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1910 << E->getSourceRange(); 1911 else 1912 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1913 << E->getSourceRange(); 1914 // Accept, even if we emitted an error diagnostic. 1915 return false; 1916 } 1917 1918 // None of the above, just randomly invalid non-lvalue. 1919 return true; 1920} 1921 1922/// isOperandMentioned - Return true if the specified operand # is mentioned 1923/// anywhere in the decomposed asm string. 1924static bool isOperandMentioned(unsigned OpNo, 1925 ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 1926 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 1927 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 1928 if (!Piece.isOperand()) continue; 1929 1930 // If this is a reference to the input and if the input was the smaller 1931 // one, then we have to reject this asm. 1932 if (Piece.getOperandNo() == OpNo) 1933 return true; 1934 } 1935 1936 return false; 1937} 1938 1939StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 1940 bool IsVolatile, unsigned NumOutputs, 1941 unsigned NumInputs, IdentifierInfo **Names, 1942 MultiExprArg constraints, MultiExprArg exprs, 1943 Expr *asmString, MultiExprArg clobbers, 1944 SourceLocation RParenLoc, bool MSAsm) { 1945 unsigned NumClobbers = clobbers.size(); 1946 StringLiteral **Constraints = 1947 reinterpret_cast<StringLiteral**>(constraints.get()); 1948 Expr **Exprs = exprs.get(); 1949 StringLiteral *AsmString = cast<StringLiteral>(asmString); 1950 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1951 1952 SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1953 1954 // The parser verifies that there is a string literal here. 1955 if (!AsmString->isAscii()) 1956 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1957 << AsmString->getSourceRange()); 1958 1959 for (unsigned i = 0; i != NumOutputs; i++) { 1960 StringLiteral *Literal = Constraints[i]; 1961 if (!Literal->isAscii()) 1962 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1963 << Literal->getSourceRange()); 1964 1965 StringRef OutputName; 1966 if (Names[i]) 1967 OutputName = Names[i]->getName(); 1968 1969 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1970 if (!Context.Target.validateOutputConstraint(Info)) 1971 return StmtError(Diag(Literal->getLocStart(), 1972 diag::err_asm_invalid_output_constraint) 1973 << Info.getConstraintStr()); 1974 1975 // Check that the output exprs are valid lvalues. 1976 Expr *OutputExpr = Exprs[i]; 1977 if (CheckAsmLValue(OutputExpr, *this)) { 1978 return StmtError(Diag(OutputExpr->getLocStart(), 1979 diag::err_asm_invalid_lvalue_in_output) 1980 << OutputExpr->getSourceRange()); 1981 } 1982 1983 OutputConstraintInfos.push_back(Info); 1984 } 1985 1986 SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1987 1988 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1989 StringLiteral *Literal = Constraints[i]; 1990 if (!Literal->isAscii()) 1991 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1992 << Literal->getSourceRange()); 1993 1994 StringRef InputName; 1995 if (Names[i]) 1996 InputName = Names[i]->getName(); 1997 1998 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1999 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 2000 NumOutputs, Info)) { 2001 return StmtError(Diag(Literal->getLocStart(), 2002 diag::err_asm_invalid_input_constraint) 2003 << Info.getConstraintStr()); 2004 } 2005 2006 Expr *InputExpr = Exprs[i]; 2007 2008 // Only allow void types for memory constraints. 2009 if (Info.allowsMemory() && !Info.allowsRegister()) { 2010 if (CheckAsmLValue(InputExpr, *this)) 2011 return StmtError(Diag(InputExpr->getLocStart(), 2012 diag::err_asm_invalid_lvalue_in_input) 2013 << Info.getConstraintStr() 2014 << InputExpr->getSourceRange()); 2015 } 2016 2017 if (Info.allowsRegister()) { 2018 if (InputExpr->getType()->isVoidType()) { 2019 return StmtError(Diag(InputExpr->getLocStart(), 2020 diag::err_asm_invalid_type_in_input) 2021 << InputExpr->getType() << Info.getConstraintStr() 2022 << InputExpr->getSourceRange()); 2023 } 2024 } 2025 2026 ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]); 2027 if (Result.isInvalid()) 2028 return StmtError(); 2029 2030 Exprs[i] = Result.take(); 2031 InputConstraintInfos.push_back(Info); 2032 } 2033 2034 // Check that the clobbers are valid. 2035 for (unsigned i = 0; i != NumClobbers; i++) { 2036 StringLiteral *Literal = Clobbers[i]; 2037 if (!Literal->isAscii()) 2038 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 2039 << Literal->getSourceRange()); 2040 2041 StringRef Clobber = Literal->getString(); 2042 2043 if (!Context.Target.isValidClobber(Clobber)) 2044 return StmtError(Diag(Literal->getLocStart(), 2045 diag::err_asm_unknown_register_name) << Clobber); 2046 } 2047 2048 AsmStmt *NS = 2049 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 2050 NumOutputs, NumInputs, Names, Constraints, Exprs, 2051 AsmString, NumClobbers, Clobbers, RParenLoc); 2052 // Validate the asm string, ensuring it makes sense given the operands we 2053 // have. 2054 SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 2055 unsigned DiagOffs; 2056 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 2057 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 2058 << AsmString->getSourceRange(); 2059 return StmtError(); 2060 } 2061 2062 // Validate tied input operands for type mismatches. 2063 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 2064 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 2065 2066 // If this is a tied constraint, verify that the output and input have 2067 // either exactly the same type, or that they are int/ptr operands with the 2068 // same size (int/long, int*/long, are ok etc). 2069 if (!Info.hasTiedOperand()) continue; 2070 2071 unsigned TiedTo = Info.getTiedOperand(); 2072 unsigned InputOpNo = i+NumOutputs; 2073 Expr *OutputExpr = Exprs[TiedTo]; 2074 Expr *InputExpr = Exprs[InputOpNo]; 2075 QualType InTy = InputExpr->getType(); 2076 QualType OutTy = OutputExpr->getType(); 2077 if (Context.hasSameType(InTy, OutTy)) 2078 continue; // All types can be tied to themselves. 2079 2080 // Decide if the input and output are in the same domain (integer/ptr or 2081 // floating point. 2082 enum AsmDomain { 2083 AD_Int, AD_FP, AD_Other 2084 } InputDomain, OutputDomain; 2085 2086 if (InTy->isIntegerType() || InTy->isPointerType()) 2087 InputDomain = AD_Int; 2088 else if (InTy->isRealFloatingType()) 2089 InputDomain = AD_FP; 2090 else 2091 InputDomain = AD_Other; 2092 2093 if (OutTy->isIntegerType() || OutTy->isPointerType()) 2094 OutputDomain = AD_Int; 2095 else if (OutTy->isRealFloatingType()) 2096 OutputDomain = AD_FP; 2097 else 2098 OutputDomain = AD_Other; 2099 2100 // They are ok if they are the same size and in the same domain. This 2101 // allows tying things like: 2102 // void* to int* 2103 // void* to int if they are the same size. 2104 // double to long double if they are the same size. 2105 // 2106 uint64_t OutSize = Context.getTypeSize(OutTy); 2107 uint64_t InSize = Context.getTypeSize(InTy); 2108 if (OutSize == InSize && InputDomain == OutputDomain && 2109 InputDomain != AD_Other) 2110 continue; 2111 2112 // If the smaller input/output operand is not mentioned in the asm string, 2113 // then we can promote the smaller one to a larger input and the asm string 2114 // won't notice. 2115 bool SmallerValueMentioned = false; 2116 2117 // If this is a reference to the input and if the input was the smaller 2118 // one, then we have to reject this asm. 2119 if (isOperandMentioned(InputOpNo, Pieces)) { 2120 // This is a use in the asm string of the smaller operand. Since we 2121 // codegen this by promoting to a wider value, the asm will get printed 2122 // "wrong". 2123 SmallerValueMentioned |= InSize < OutSize; 2124 } 2125 if (isOperandMentioned(TiedTo, Pieces)) { 2126 // If this is a reference to the output, and if the output is the larger 2127 // value, then it's ok because we'll promote the input to the larger type. 2128 SmallerValueMentioned |= OutSize < InSize; 2129 } 2130 2131 // If the smaller value wasn't mentioned in the asm string, and if the 2132 // output was a register, just extend the shorter one to the size of the 2133 // larger one. 2134 if (!SmallerValueMentioned && InputDomain != AD_Other && 2135 OutputConstraintInfos[TiedTo].allowsRegister()) 2136 continue; 2137 2138 // Either both of the operands were mentioned or the smaller one was 2139 // mentioned. One more special case that we'll allow: if the tied input is 2140 // integer, unmentioned, and is a constant, then we'll allow truncating it 2141 // down to the size of the destination. 2142 if (InputDomain == AD_Int && OutputDomain == AD_Int && 2143 !isOperandMentioned(InputOpNo, Pieces) && 2144 InputExpr->isEvaluatable(Context)) { 2145 CastKind castKind = 2146 (OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast); 2147 InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).take(); 2148 Exprs[InputOpNo] = InputExpr; 2149 NS->setInputExpr(i, InputExpr); 2150 continue; 2151 } 2152 2153 Diag(InputExpr->getLocStart(), 2154 diag::err_asm_tying_incompatible_types) 2155 << InTy << OutTy << OutputExpr->getSourceRange() 2156 << InputExpr->getSourceRange(); 2157 return StmtError(); 2158 } 2159 2160 return Owned(NS); 2161} 2162 2163StmtResult 2164Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 2165 SourceLocation RParen, Decl *Parm, 2166 Stmt *Body) { 2167 VarDecl *Var = cast_or_null<VarDecl>(Parm); 2168 if (Var && Var->isInvalidDecl()) 2169 return StmtError(); 2170 2171 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 2172} 2173 2174StmtResult 2175Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 2176 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 2177} 2178 2179StmtResult 2180Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 2181 MultiStmtArg CatchStmts, Stmt *Finally) { 2182 if (!getLangOptions().ObjCExceptions) 2183 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 2184 2185 getCurFunction()->setHasBranchProtectedScope(); 2186 unsigned NumCatchStmts = CatchStmts.size(); 2187 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 2188 CatchStmts.release(), 2189 NumCatchStmts, 2190 Finally)); 2191} 2192 2193StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 2194 Expr *Throw) { 2195 if (Throw) { 2196 Throw = MaybeCreateExprWithCleanups(Throw); 2197 ExprResult Result = DefaultLvalueConversion(Throw); 2198 if (Result.isInvalid()) 2199 return StmtError(); 2200 2201 Throw = Result.take(); 2202 QualType ThrowType = Throw->getType(); 2203 // Make sure the expression type is an ObjC pointer or "void *". 2204 if (!ThrowType->isDependentType() && 2205 !ThrowType->isObjCObjectPointerType()) { 2206 const PointerType *PT = ThrowType->getAs<PointerType>(); 2207 if (!PT || !PT->getPointeeType()->isVoidType()) 2208 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 2209 << Throw->getType() << Throw->getSourceRange()); 2210 } 2211 } 2212 2213 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 2214} 2215 2216StmtResult 2217Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 2218 Scope *CurScope) { 2219 if (!getLangOptions().ObjCExceptions) 2220 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 2221 2222 if (!Throw) { 2223 // @throw without an expression designates a rethrow (which much occur 2224 // in the context of an @catch clause). 2225 Scope *AtCatchParent = CurScope; 2226 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 2227 AtCatchParent = AtCatchParent->getParent(); 2228 if (!AtCatchParent) 2229 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 2230 } 2231 2232 return BuildObjCAtThrowStmt(AtLoc, Throw); 2233} 2234 2235StmtResult 2236Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 2237 Stmt *SyncBody) { 2238 getCurFunction()->setHasBranchProtectedScope(); 2239 2240 ExprResult Result = DefaultLvalueConversion(SyncExpr); 2241 if (Result.isInvalid()) 2242 return StmtError(); 2243 2244 SyncExpr = Result.take(); 2245 // Make sure the expression type is an ObjC pointer or "void *". 2246 if (!SyncExpr->getType()->isDependentType() && 2247 !SyncExpr->getType()->isObjCObjectPointerType()) { 2248 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 2249 if (!PT || !PT->getPointeeType()->isVoidType()) 2250 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 2251 << SyncExpr->getType() << SyncExpr->getSourceRange()); 2252 } 2253 2254 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 2255} 2256 2257/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 2258/// and creates a proper catch handler from them. 2259StmtResult 2260Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 2261 Stmt *HandlerBlock) { 2262 // There's nothing to test that ActOnExceptionDecl didn't already test. 2263 return Owned(new (Context) CXXCatchStmt(CatchLoc, 2264 cast_or_null<VarDecl>(ExDecl), 2265 HandlerBlock)); 2266} 2267 2268StmtResult 2269Sema::ActOnObjCAutoreleasePoolStmt(SourceLocation AtLoc, Stmt *Body) { 2270 getCurFunction()->setHasBranchProtectedScope(); 2271 return Owned(new (Context) ObjCAutoreleasePoolStmt(AtLoc, Body)); 2272} 2273 2274namespace { 2275 2276class TypeWithHandler { 2277 QualType t; 2278 CXXCatchStmt *stmt; 2279public: 2280 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 2281 : t(type), stmt(statement) {} 2282 2283 // An arbitrary order is fine as long as it places identical 2284 // types next to each other. 2285 bool operator<(const TypeWithHandler &y) const { 2286 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 2287 return true; 2288 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 2289 return false; 2290 else 2291 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 2292 } 2293 2294 bool operator==(const TypeWithHandler& other) const { 2295 return t == other.t; 2296 } 2297 2298 CXXCatchStmt *getCatchStmt() const { return stmt; } 2299 SourceLocation getTypeSpecStartLoc() const { 2300 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 2301 } 2302}; 2303 2304} 2305 2306/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 2307/// handlers and creates a try statement from them. 2308StmtResult 2309Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 2310 MultiStmtArg RawHandlers) { 2311 // Don't report an error if 'try' is used in system headers. 2312 if (!getLangOptions().CXXExceptions && 2313 !getSourceManager().isInSystemHeader(TryLoc)) 2314 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 2315 2316 unsigned NumHandlers = RawHandlers.size(); 2317 assert(NumHandlers > 0 && 2318 "The parser shouldn't call this if there are no handlers."); 2319 Stmt **Handlers = RawHandlers.get(); 2320 2321 SmallVector<TypeWithHandler, 8> TypesWithHandlers; 2322 2323 for (unsigned i = 0; i < NumHandlers; ++i) { 2324 CXXCatchStmt *Handler = cast<CXXCatchStmt>(Handlers[i]); 2325 if (!Handler->getExceptionDecl()) { 2326 if (i < NumHandlers - 1) 2327 return StmtError(Diag(Handler->getLocStart(), 2328 diag::err_early_catch_all)); 2329 2330 continue; 2331 } 2332 2333 const QualType CaughtType = Handler->getCaughtType(); 2334 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 2335 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 2336 } 2337 2338 // Detect handlers for the same type as an earlier one. 2339 if (NumHandlers > 1) { 2340 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 2341 2342 TypeWithHandler prev = TypesWithHandlers[0]; 2343 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 2344 TypeWithHandler curr = TypesWithHandlers[i]; 2345 2346 if (curr == prev) { 2347 Diag(curr.getTypeSpecStartLoc(), 2348 diag::warn_exception_caught_by_earlier_handler) 2349 << curr.getCatchStmt()->getCaughtType().getAsString(); 2350 Diag(prev.getTypeSpecStartLoc(), 2351 diag::note_previous_exception_handler) 2352 << prev.getCatchStmt()->getCaughtType().getAsString(); 2353 } 2354 2355 prev = curr; 2356 } 2357 } 2358 2359 getCurFunction()->setHasBranchProtectedScope(); 2360 2361 // FIXME: We should detect handlers that cannot catch anything because an 2362 // earlier handler catches a superclass. Need to find a method that is not 2363 // quadratic for this. 2364 // Neither of these are explicitly forbidden, but every compiler detects them 2365 // and warns. 2366 2367 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 2368 Handlers, NumHandlers)); 2369} 2370 2371StmtResult 2372Sema::ActOnSEHTryBlock(bool IsCXXTry, 2373 SourceLocation TryLoc, 2374 Stmt *TryBlock, 2375 Stmt *Handler) { 2376 assert(TryBlock && Handler); 2377 2378 getCurFunction()->setHasBranchProtectedScope(); 2379 2380 return Owned(SEHTryStmt::Create(Context,IsCXXTry,TryLoc,TryBlock,Handler)); 2381} 2382 2383StmtResult 2384Sema::ActOnSEHExceptBlock(SourceLocation Loc, 2385 Expr *FilterExpr, 2386 Stmt *Block) { 2387 assert(FilterExpr && Block); 2388 2389 if(!FilterExpr->getType()->isIntegerType()) { 2390 return StmtError(Diag(FilterExpr->getExprLoc(), 2391 diag::err_filter_expression_integral) 2392 << FilterExpr->getType()); 2393 } 2394 2395 return Owned(SEHExceptStmt::Create(Context,Loc,FilterExpr,Block)); 2396} 2397 2398StmtResult 2399Sema::ActOnSEHFinallyBlock(SourceLocation Loc, 2400 Stmt *Block) { 2401 assert(Block); 2402 return Owned(SEHFinallyStmt::Create(Context,Loc,Block)); 2403} 2404