SemaStmt.cpp revision 203548ba4b72e7e59320d352afc1eb0b5ab131de
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/AST/APValue.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/DeclObjC.h" 21#include "clang/AST/ExprCXX.h" 22#include "clang/AST/ExprObjC.h" 23#include "clang/AST/StmtObjC.h" 24#include "clang/AST/StmtCXX.h" 25#include "clang/AST/TypeLoc.h" 26#include "clang/Lex/Preprocessor.h" 27#include "clang/Basic/TargetInfo.h" 28#include "llvm/ADT/ArrayRef.h" 29#include "llvm/ADT/STLExtras.h" 30#include "llvm/ADT/SmallVector.h" 31using namespace clang; 32using namespace sema; 33 34StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 35 Expr *E = expr.get(); 36 if (!E) // FIXME: FullExprArg has no error state? 37 return StmtError(); 38 39 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 40 // void expression for its side effects. Conversion to void allows any 41 // operand, even incomplete types. 42 43 // Same thing in for stmt first clause (when expr) and third clause. 44 return Owned(static_cast<Stmt*>(E)); 45} 46 47 48StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, bool LeadingEmptyMacro) { 49 return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacro)); 50} 51 52StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 53 SourceLocation EndLoc) { 54 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 55 56 // If we have an invalid decl, just return an error. 57 if (DG.isNull()) return StmtError(); 58 59 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 60} 61 62void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 63 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 64 65 // If we have an invalid decl, just return. 66 if (DG.isNull() || !DG.isSingleDecl()) return; 67 // suppress any potential 'unused variable' warning. 68 DG.getSingleDecl()->setUsed(); 69} 70 71void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 72 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 73 return DiagnoseUnusedExprResult(Label->getSubStmt()); 74 75 const Expr *E = dyn_cast_or_null<Expr>(S); 76 if (!E) 77 return; 78 79 if (E->isBoundMemberFunction(Context)) { 80 Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func) 81 << E->getSourceRange(); 82 return; 83 } 84 85 SourceLocation Loc; 86 SourceRange R1, R2; 87 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 88 return; 89 90 // Okay, we have an unused result. Depending on what the base expression is, 91 // we might want to make a more specific diagnostic. Check for one of these 92 // cases now. 93 unsigned DiagID = diag::warn_unused_expr; 94 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 95 E = Temps->getSubExpr(); 96 if (const CXXBindTemporaryExpr *TempExpr = dyn_cast<CXXBindTemporaryExpr>(E)) 97 E = TempExpr->getSubExpr(); 98 99 E = E->IgnoreParenImpCasts(); 100 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 101 if (E->getType()->isVoidType()) 102 return; 103 104 // If the callee has attribute pure, const, or warn_unused_result, warn with 105 // a more specific message to make it clear what is happening. 106 if (const Decl *FD = CE->getCalleeDecl()) { 107 if (FD->getAttr<WarnUnusedResultAttr>()) { 108 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 109 return; 110 } 111 if (FD->getAttr<PureAttr>()) { 112 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 113 return; 114 } 115 if (FD->getAttr<ConstAttr>()) { 116 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 117 return; 118 } 119 } 120 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 121 const ObjCMethodDecl *MD = ME->getMethodDecl(); 122 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 123 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 124 return; 125 } 126 } else if (isa<ObjCPropertyRefExpr>(E)) { 127 DiagID = diag::warn_unused_property_expr; 128 } else if (const CXXFunctionalCastExpr *FC 129 = dyn_cast<CXXFunctionalCastExpr>(E)) { 130 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 131 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 132 return; 133 } 134 // Diagnose "(void*) blah" as a typo for "(void) blah". 135 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 136 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 137 QualType T = TI->getType(); 138 139 // We really do want to use the non-canonical type here. 140 if (T == Context.VoidPtrTy) { 141 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 142 143 Diag(Loc, diag::warn_unused_voidptr) 144 << FixItHint::CreateRemoval(TL.getStarLoc()); 145 return; 146 } 147 } 148 149 DiagRuntimeBehavior(Loc, 0, PDiag(DiagID) << R1 << R2); 150} 151 152StmtResult 153Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 154 MultiStmtArg elts, bool isStmtExpr) { 155 unsigned NumElts = elts.size(); 156 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 157 // If we're in C89 mode, check that we don't have any decls after stmts. If 158 // so, emit an extension diagnostic. 159 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 160 // Note that __extension__ can be around a decl. 161 unsigned i = 0; 162 // Skip over all declarations. 163 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 164 /*empty*/; 165 166 // We found the end of the list or a statement. Scan for another declstmt. 167 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 168 /*empty*/; 169 170 if (i != NumElts) { 171 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 172 Diag(D->getLocation(), diag::ext_mixed_decls_code); 173 } 174 } 175 // Warn about unused expressions in statements. 176 for (unsigned i = 0; i != NumElts; ++i) { 177 // Ignore statements that are last in a statement expression. 178 if (isStmtExpr && i == NumElts - 1) 179 continue; 180 181 DiagnoseUnusedExprResult(Elts[i]); 182 } 183 184 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 185} 186 187StmtResult 188Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 189 SourceLocation DotDotDotLoc, Expr *RHSVal, 190 SourceLocation ColonLoc) { 191 assert((LHSVal != 0) && "missing expression in case statement"); 192 193 // C99 6.8.4.2p3: The expression shall be an integer constant. 194 // However, GCC allows any evaluatable integer expression. 195 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 196 VerifyIntegerConstantExpression(LHSVal)) 197 return StmtError(); 198 199 // GCC extension: The expression shall be an integer constant. 200 201 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 202 VerifyIntegerConstantExpression(RHSVal)) { 203 RHSVal = 0; // Recover by just forgetting about it. 204 } 205 206 if (getCurFunction()->SwitchStack.empty()) { 207 Diag(CaseLoc, diag::err_case_not_in_switch); 208 return StmtError(); 209 } 210 211 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 212 ColonLoc); 213 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 214 return Owned(CS); 215} 216 217/// ActOnCaseStmtBody - This installs a statement as the body of a case. 218void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 219 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 220 CS->setSubStmt(SubStmt); 221} 222 223StmtResult 224Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 225 Stmt *SubStmt, Scope *CurScope) { 226 if (getCurFunction()->SwitchStack.empty()) { 227 Diag(DefaultLoc, diag::err_default_not_in_switch); 228 return Owned(SubStmt); 229 } 230 231 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 232 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 233 return Owned(DS); 234} 235 236StmtResult 237Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 238 SourceLocation ColonLoc, Stmt *SubStmt) { 239 240 // If the label was multiply defined, reject it now. 241 if (TheDecl->getStmt()) { 242 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 243 Diag(TheDecl->getLocation(), diag::note_previous_definition); 244 return Owned(SubStmt); 245 } 246 247 // Otherwise, things are good. Fill in the declaration and return it. 248 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 249 TheDecl->setStmt(LS); 250 if (!TheDecl->isGnuLocal()) 251 TheDecl->setLocation(IdentLoc); 252 return Owned(LS); 253} 254 255StmtResult 256Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 257 Stmt *thenStmt, SourceLocation ElseLoc, 258 Stmt *elseStmt) { 259 ExprResult CondResult(CondVal.release()); 260 261 VarDecl *ConditionVar = 0; 262 if (CondVar) { 263 ConditionVar = cast<VarDecl>(CondVar); 264 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 265 if (CondResult.isInvalid()) 266 return StmtError(); 267 } 268 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 269 if (!ConditionExpr) 270 return StmtError(); 271 272 DiagnoseUnusedExprResult(thenStmt); 273 274 // Warn if the if block has a null body without an else value. 275 // this helps prevent bugs due to typos, such as 276 // if (condition); 277 // do_stuff(); 278 // 279 if (!elseStmt) { 280 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 281 // But do not warn if the body is a macro that expands to nothing, e.g: 282 // 283 // #define CALL(x) 284 // if (condition) 285 // CALL(0); 286 // 287 if (!stmt->hasLeadingEmptyMacro()) 288 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 289 } 290 291 DiagnoseUnusedExprResult(elseStmt); 292 293 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 294 thenStmt, ElseLoc, elseStmt)); 295} 296 297/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 298/// the specified width and sign. If an overflow occurs, detect it and emit 299/// the specified diagnostic. 300void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 301 unsigned NewWidth, bool NewSign, 302 SourceLocation Loc, 303 unsigned DiagID) { 304 // Perform a conversion to the promoted condition type if needed. 305 if (NewWidth > Val.getBitWidth()) { 306 // If this is an extension, just do it. 307 Val = Val.extend(NewWidth); 308 Val.setIsSigned(NewSign); 309 310 // If the input was signed and negative and the output is 311 // unsigned, don't bother to warn: this is implementation-defined 312 // behavior. 313 // FIXME: Introduce a second, default-ignored warning for this case? 314 } else if (NewWidth < Val.getBitWidth()) { 315 // If this is a truncation, check for overflow. 316 llvm::APSInt ConvVal(Val); 317 ConvVal = ConvVal.trunc(NewWidth); 318 ConvVal.setIsSigned(NewSign); 319 ConvVal = ConvVal.extend(Val.getBitWidth()); 320 ConvVal.setIsSigned(Val.isSigned()); 321 if (ConvVal != Val) 322 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 323 324 // Regardless of whether a diagnostic was emitted, really do the 325 // truncation. 326 Val = Val.trunc(NewWidth); 327 Val.setIsSigned(NewSign); 328 } else if (NewSign != Val.isSigned()) { 329 // Convert the sign to match the sign of the condition. This can cause 330 // overflow as well: unsigned(INTMIN) 331 // We don't diagnose this overflow, because it is implementation-defined 332 // behavior. 333 // FIXME: Introduce a second, default-ignored warning for this case? 334 llvm::APSInt OldVal(Val); 335 Val.setIsSigned(NewSign); 336 } 337} 338 339namespace { 340 struct CaseCompareFunctor { 341 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 342 const llvm::APSInt &RHS) { 343 return LHS.first < RHS; 344 } 345 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 346 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 347 return LHS.first < RHS.first; 348 } 349 bool operator()(const llvm::APSInt &LHS, 350 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 351 return LHS < RHS.first; 352 } 353 }; 354} 355 356/// CmpCaseVals - Comparison predicate for sorting case values. 357/// 358static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 359 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 360 if (lhs.first < rhs.first) 361 return true; 362 363 if (lhs.first == rhs.first && 364 lhs.second->getCaseLoc().getRawEncoding() 365 < rhs.second->getCaseLoc().getRawEncoding()) 366 return true; 367 return false; 368} 369 370/// CmpEnumVals - Comparison predicate for sorting enumeration values. 371/// 372static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 373 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 374{ 375 return lhs.first < rhs.first; 376} 377 378/// EqEnumVals - Comparison preficate for uniqing enumeration values. 379/// 380static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 381 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 382{ 383 return lhs.first == rhs.first; 384} 385 386/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 387/// potentially integral-promoted expression @p expr. 388static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 389 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 390 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 391 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 392 if (TypeBeforePromotion->isIntegralOrEnumerationType()) { 393 return TypeBeforePromotion; 394 } 395 } 396 return expr->getType(); 397} 398 399StmtResult 400Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 401 Decl *CondVar) { 402 ExprResult CondResult; 403 404 VarDecl *ConditionVar = 0; 405 if (CondVar) { 406 ConditionVar = cast<VarDecl>(CondVar); 407 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 408 if (CondResult.isInvalid()) 409 return StmtError(); 410 411 Cond = CondResult.release(); 412 } 413 414 if (!Cond) 415 return StmtError(); 416 417 CondResult 418 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 419 PDiag(diag::err_typecheck_statement_requires_integer), 420 PDiag(diag::err_switch_incomplete_class_type) 421 << Cond->getSourceRange(), 422 PDiag(diag::err_switch_explicit_conversion), 423 PDiag(diag::note_switch_conversion), 424 PDiag(diag::err_switch_multiple_conversions), 425 PDiag(diag::note_switch_conversion), 426 PDiag(0)); 427 if (CondResult.isInvalid()) return StmtError(); 428 Cond = CondResult.take(); 429 430 if (!CondVar) { 431 CheckImplicitConversions(Cond, SwitchLoc); 432 CondResult = MaybeCreateExprWithCleanups(Cond); 433 if (CondResult.isInvalid()) 434 return StmtError(); 435 Cond = CondResult.take(); 436 } 437 438 getCurFunction()->setHasBranchIntoScope(); 439 440 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 441 getCurFunction()->SwitchStack.push_back(SS); 442 return Owned(SS); 443} 444 445static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 446 if (Val.getBitWidth() < BitWidth) 447 Val = Val.extend(BitWidth); 448 else if (Val.getBitWidth() > BitWidth) 449 Val = Val.trunc(BitWidth); 450 Val.setIsSigned(IsSigned); 451} 452 453StmtResult 454Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 455 Stmt *BodyStmt) { 456 SwitchStmt *SS = cast<SwitchStmt>(Switch); 457 assert(SS == getCurFunction()->SwitchStack.back() && 458 "switch stack missing push/pop!"); 459 460 SS->setBody(BodyStmt, SwitchLoc); 461 getCurFunction()->SwitchStack.pop_back(); 462 463 if (SS->getCond() == 0) 464 return StmtError(); 465 466 Expr *CondExpr = SS->getCond(); 467 Expr *CondExprBeforePromotion = CondExpr; 468 QualType CondTypeBeforePromotion = 469 GetTypeBeforeIntegralPromotion(CondExpr); 470 471 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 472 UsualUnaryConversions(CondExpr); 473 QualType CondType = CondExpr->getType(); 474 SS->setCond(CondExpr); 475 476 // C++ 6.4.2.p2: 477 // Integral promotions are performed (on the switch condition). 478 // 479 // A case value unrepresentable by the original switch condition 480 // type (before the promotion) doesn't make sense, even when it can 481 // be represented by the promoted type. Therefore we need to find 482 // the pre-promotion type of the switch condition. 483 if (!CondExpr->isTypeDependent()) { 484 // We have already converted the expression to an integral or enumeration 485 // type, when we started the switch statement. If we don't have an 486 // appropriate type now, just return an error. 487 if (!CondType->isIntegralOrEnumerationType()) 488 return StmtError(); 489 490 if (CondExpr->isKnownToHaveBooleanValue()) { 491 // switch(bool_expr) {...} is often a programmer error, e.g. 492 // switch(n && mask) { ... } // Doh - should be "n & mask". 493 // One can always use an if statement instead of switch(bool_expr). 494 Diag(SwitchLoc, diag::warn_bool_switch_condition) 495 << CondExpr->getSourceRange(); 496 } 497 } 498 499 // Get the bitwidth of the switched-on value before promotions. We must 500 // convert the integer case values to this width before comparison. 501 bool HasDependentValue 502 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 503 unsigned CondWidth 504 = HasDependentValue ? 0 : Context.getIntWidth(CondTypeBeforePromotion); 505 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 506 507 // Accumulate all of the case values in a vector so that we can sort them 508 // and detect duplicates. This vector contains the APInt for the case after 509 // it has been converted to the condition type. 510 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 511 CaseValsTy CaseVals; 512 513 // Keep track of any GNU case ranges we see. The APSInt is the low value. 514 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 515 CaseRangesTy CaseRanges; 516 517 DefaultStmt *TheDefaultStmt = 0; 518 519 bool CaseListIsErroneous = false; 520 521 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 522 SC = SC->getNextSwitchCase()) { 523 524 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 525 if (TheDefaultStmt) { 526 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 527 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 528 529 // FIXME: Remove the default statement from the switch block so that 530 // we'll return a valid AST. This requires recursing down the AST and 531 // finding it, not something we are set up to do right now. For now, 532 // just lop the entire switch stmt out of the AST. 533 CaseListIsErroneous = true; 534 } 535 TheDefaultStmt = DS; 536 537 } else { 538 CaseStmt *CS = cast<CaseStmt>(SC); 539 540 // We already verified that the expression has a i-c-e value (C99 541 // 6.8.4.2p3) - get that value now. 542 Expr *Lo = CS->getLHS(); 543 544 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 545 HasDependentValue = true; 546 break; 547 } 548 549 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 550 551 // Convert the value to the same width/sign as the condition. 552 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 553 Lo->getLocStart(), 554 diag::warn_case_value_overflow); 555 556 // If the LHS is not the same type as the condition, insert an implicit 557 // cast. 558 ImpCastExprToType(Lo, CondType, CK_IntegralCast); 559 CS->setLHS(Lo); 560 561 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 562 if (CS->getRHS()) { 563 if (CS->getRHS()->isTypeDependent() || 564 CS->getRHS()->isValueDependent()) { 565 HasDependentValue = true; 566 break; 567 } 568 CaseRanges.push_back(std::make_pair(LoVal, CS)); 569 } else 570 CaseVals.push_back(std::make_pair(LoVal, CS)); 571 } 572 } 573 574 if (!HasDependentValue) { 575 // If we don't have a default statement, check whether the 576 // condition is constant. 577 llvm::APSInt ConstantCondValue; 578 bool HasConstantCond = false; 579 bool ShouldCheckConstantCond = false; 580 if (!HasDependentValue && !TheDefaultStmt) { 581 Expr::EvalResult Result; 582 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 583 if (HasConstantCond) { 584 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 585 ConstantCondValue = Result.Val.getInt(); 586 ShouldCheckConstantCond = true; 587 588 assert(ConstantCondValue.getBitWidth() == CondWidth && 589 ConstantCondValue.isSigned() == CondIsSigned); 590 } 591 } 592 593 // Sort all the scalar case values so we can easily detect duplicates. 594 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 595 596 if (!CaseVals.empty()) { 597 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 598 if (ShouldCheckConstantCond && 599 CaseVals[i].first == ConstantCondValue) 600 ShouldCheckConstantCond = false; 601 602 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 603 // If we have a duplicate, report it. 604 Diag(CaseVals[i].second->getLHS()->getLocStart(), 605 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 606 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 607 diag::note_duplicate_case_prev); 608 // FIXME: We really want to remove the bogus case stmt from the 609 // substmt, but we have no way to do this right now. 610 CaseListIsErroneous = true; 611 } 612 } 613 } 614 615 // Detect duplicate case ranges, which usually don't exist at all in 616 // the first place. 617 if (!CaseRanges.empty()) { 618 // Sort all the case ranges by their low value so we can easily detect 619 // overlaps between ranges. 620 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 621 622 // Scan the ranges, computing the high values and removing empty ranges. 623 std::vector<llvm::APSInt> HiVals; 624 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 625 llvm::APSInt &LoVal = CaseRanges[i].first; 626 CaseStmt *CR = CaseRanges[i].second; 627 Expr *Hi = CR->getRHS(); 628 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 629 630 // Convert the value to the same width/sign as the condition. 631 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 632 Hi->getLocStart(), 633 diag::warn_case_value_overflow); 634 635 // If the LHS is not the same type as the condition, insert an implicit 636 // cast. 637 ImpCastExprToType(Hi, CondType, CK_IntegralCast); 638 CR->setRHS(Hi); 639 640 // If the low value is bigger than the high value, the case is empty. 641 if (LoVal > HiVal) { 642 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 643 << SourceRange(CR->getLHS()->getLocStart(), 644 Hi->getLocEnd()); 645 CaseRanges.erase(CaseRanges.begin()+i); 646 --i, --e; 647 continue; 648 } 649 650 if (ShouldCheckConstantCond && 651 LoVal <= ConstantCondValue && 652 ConstantCondValue <= HiVal) 653 ShouldCheckConstantCond = false; 654 655 HiVals.push_back(HiVal); 656 } 657 658 // Rescan the ranges, looking for overlap with singleton values and other 659 // ranges. Since the range list is sorted, we only need to compare case 660 // ranges with their neighbors. 661 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 662 llvm::APSInt &CRLo = CaseRanges[i].first; 663 llvm::APSInt &CRHi = HiVals[i]; 664 CaseStmt *CR = CaseRanges[i].second; 665 666 // Check to see whether the case range overlaps with any 667 // singleton cases. 668 CaseStmt *OverlapStmt = 0; 669 llvm::APSInt OverlapVal(32); 670 671 // Find the smallest value >= the lower bound. If I is in the 672 // case range, then we have overlap. 673 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 674 CaseVals.end(), CRLo, 675 CaseCompareFunctor()); 676 if (I != CaseVals.end() && I->first < CRHi) { 677 OverlapVal = I->first; // Found overlap with scalar. 678 OverlapStmt = I->second; 679 } 680 681 // Find the smallest value bigger than the upper bound. 682 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 683 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 684 OverlapVal = (I-1)->first; // Found overlap with scalar. 685 OverlapStmt = (I-1)->second; 686 } 687 688 // Check to see if this case stmt overlaps with the subsequent 689 // case range. 690 if (i && CRLo <= HiVals[i-1]) { 691 OverlapVal = HiVals[i-1]; // Found overlap with range. 692 OverlapStmt = CaseRanges[i-1].second; 693 } 694 695 if (OverlapStmt) { 696 // If we have a duplicate, report it. 697 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 698 << OverlapVal.toString(10); 699 Diag(OverlapStmt->getLHS()->getLocStart(), 700 diag::note_duplicate_case_prev); 701 // FIXME: We really want to remove the bogus case stmt from the 702 // substmt, but we have no way to do this right now. 703 CaseListIsErroneous = true; 704 } 705 } 706 } 707 708 // Complain if we have a constant condition and we didn't find a match. 709 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 710 // TODO: it would be nice if we printed enums as enums, chars as 711 // chars, etc. 712 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 713 << ConstantCondValue.toString(10) 714 << CondExpr->getSourceRange(); 715 } 716 717 // Check to see if switch is over an Enum and handles all of its 718 // values. We only issue a warning if there is not 'default:', but 719 // we still do the analysis to preserve this information in the AST 720 // (which can be used by flow-based analyes). 721 // 722 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 723 724 // If switch has default case, then ignore it. 725 if (!CaseListIsErroneous && !HasConstantCond && ET) { 726 const EnumDecl *ED = ET->getDecl(); 727 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 728 EnumValsTy EnumVals; 729 730 // Gather all enum values, set their type and sort them, 731 // allowing easier comparison with CaseVals. 732 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 733 EDI != ED->enumerator_end(); ++EDI) { 734 llvm::APSInt Val = EDI->getInitVal(); 735 AdjustAPSInt(Val, CondWidth, CondIsSigned); 736 EnumVals.push_back(std::make_pair(Val, *EDI)); 737 } 738 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 739 EnumValsTy::iterator EIend = 740 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 741 742 // See which case values aren't in enum. 743 // TODO: we might want to check whether case values are out of the 744 // enum even if we don't want to check whether all cases are handled. 745 if (!TheDefaultStmt) { 746 EnumValsTy::const_iterator EI = EnumVals.begin(); 747 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 748 CI != CaseVals.end(); CI++) { 749 while (EI != EIend && EI->first < CI->first) 750 EI++; 751 if (EI == EIend || EI->first > CI->first) 752 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 753 << ED->getDeclName(); 754 } 755 // See which of case ranges aren't in enum 756 EI = EnumVals.begin(); 757 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 758 RI != CaseRanges.end() && EI != EIend; RI++) { 759 while (EI != EIend && EI->first < RI->first) 760 EI++; 761 762 if (EI == EIend || EI->first != RI->first) { 763 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 764 << ED->getDeclName(); 765 } 766 767 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 768 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 769 while (EI != EIend && EI->first < Hi) 770 EI++; 771 if (EI == EIend || EI->first != Hi) 772 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 773 << ED->getDeclName(); 774 } 775 } 776 777 // Check which enum vals aren't in switch 778 CaseValsTy::const_iterator CI = CaseVals.begin(); 779 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 780 bool hasCasesNotInSwitch = false; 781 782 llvm::SmallVector<DeclarationName,8> UnhandledNames; 783 784 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 785 // Drop unneeded case values 786 llvm::APSInt CIVal; 787 while (CI != CaseVals.end() && CI->first < EI->first) 788 CI++; 789 790 if (CI != CaseVals.end() && CI->first == EI->first) 791 continue; 792 793 // Drop unneeded case ranges 794 for (; RI != CaseRanges.end(); RI++) { 795 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 796 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 797 if (EI->first <= Hi) 798 break; 799 } 800 801 if (RI == CaseRanges.end() || EI->first < RI->first) { 802 hasCasesNotInSwitch = true; 803 if (!TheDefaultStmt) 804 UnhandledNames.push_back(EI->second->getDeclName()); 805 } 806 } 807 808 // Produce a nice diagnostic if multiple values aren't handled. 809 switch (UnhandledNames.size()) { 810 case 0: break; 811 case 1: 812 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 813 << UnhandledNames[0]; 814 break; 815 case 2: 816 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 817 << UnhandledNames[0] << UnhandledNames[1]; 818 break; 819 case 3: 820 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 821 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 822 break; 823 default: 824 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 825 << (unsigned)UnhandledNames.size() 826 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 827 break; 828 } 829 830 if (!hasCasesNotInSwitch) 831 SS->setAllEnumCasesCovered(); 832 } 833 } 834 835 // FIXME: If the case list was broken is some way, we don't have a good system 836 // to patch it up. Instead, just return the whole substmt as broken. 837 if (CaseListIsErroneous) 838 return StmtError(); 839 840 return Owned(SS); 841} 842 843StmtResult 844Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 845 Decl *CondVar, Stmt *Body) { 846 ExprResult CondResult(Cond.release()); 847 848 VarDecl *ConditionVar = 0; 849 if (CondVar) { 850 ConditionVar = cast<VarDecl>(CondVar); 851 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 852 if (CondResult.isInvalid()) 853 return StmtError(); 854 } 855 Expr *ConditionExpr = CondResult.take(); 856 if (!ConditionExpr) 857 return StmtError(); 858 859 DiagnoseUnusedExprResult(Body); 860 861 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 862 Body, WhileLoc)); 863} 864 865StmtResult 866Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 867 SourceLocation WhileLoc, SourceLocation CondLParen, 868 Expr *Cond, SourceLocation CondRParen) { 869 assert(Cond && "ActOnDoStmt(): missing expression"); 870 871 if (CheckBooleanCondition(Cond, DoLoc)) 872 return StmtError(); 873 874 CheckImplicitConversions(Cond, DoLoc); 875 ExprResult CondResult = MaybeCreateExprWithCleanups(Cond); 876 if (CondResult.isInvalid()) 877 return StmtError(); 878 Cond = CondResult.take(); 879 880 DiagnoseUnusedExprResult(Body); 881 882 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 883} 884 885StmtResult 886Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 887 Stmt *First, FullExprArg second, Decl *secondVar, 888 FullExprArg third, 889 SourceLocation RParenLoc, Stmt *Body) { 890 if (!getLangOptions().CPlusPlus) { 891 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 892 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 893 // declare identifiers for objects having storage class 'auto' or 894 // 'register'. 895 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 896 DI!=DE; ++DI) { 897 VarDecl *VD = dyn_cast<VarDecl>(*DI); 898 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 899 VD = 0; 900 if (VD == 0) 901 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 902 // FIXME: mark decl erroneous! 903 } 904 } 905 } 906 907 ExprResult SecondResult(second.release()); 908 VarDecl *ConditionVar = 0; 909 if (secondVar) { 910 ConditionVar = cast<VarDecl>(secondVar); 911 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 912 if (SecondResult.isInvalid()) 913 return StmtError(); 914 } 915 916 Expr *Third = third.release().takeAs<Expr>(); 917 918 DiagnoseUnusedExprResult(First); 919 DiagnoseUnusedExprResult(Third); 920 DiagnoseUnusedExprResult(Body); 921 922 return Owned(new (Context) ForStmt(Context, First, 923 SecondResult.take(), ConditionVar, 924 Third, Body, ForLoc, LParenLoc, 925 RParenLoc)); 926} 927 928/// In an Objective C collection iteration statement: 929/// for (x in y) 930/// x can be an arbitrary l-value expression. Bind it up as a 931/// full-expression. 932StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 933 CheckImplicitConversions(E); 934 ExprResult Result = MaybeCreateExprWithCleanups(E); 935 if (Result.isInvalid()) return StmtError(); 936 return Owned(static_cast<Stmt*>(Result.get())); 937} 938 939StmtResult 940Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 941 SourceLocation LParenLoc, 942 Stmt *First, Expr *Second, 943 SourceLocation RParenLoc, Stmt *Body) { 944 if (First) { 945 QualType FirstType; 946 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 947 if (!DS->isSingleDecl()) 948 return StmtError(Diag((*DS->decl_begin())->getLocation(), 949 diag::err_toomany_element_decls)); 950 951 Decl *D = DS->getSingleDecl(); 952 FirstType = cast<ValueDecl>(D)->getType(); 953 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 954 // declare identifiers for objects having storage class 'auto' or 955 // 'register'. 956 VarDecl *VD = cast<VarDecl>(D); 957 if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) 958 return StmtError(Diag(VD->getLocation(), 959 diag::err_non_variable_decl_in_for)); 960 } else { 961 Expr *FirstE = cast<Expr>(First); 962 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 963 return StmtError(Diag(First->getLocStart(), 964 diag::err_selector_element_not_lvalue) 965 << First->getSourceRange()); 966 967 FirstType = static_cast<Expr*>(First)->getType(); 968 } 969 if (!FirstType->isDependentType() && 970 !FirstType->isObjCObjectPointerType() && 971 !FirstType->isBlockPointerType()) 972 Diag(ForLoc, diag::err_selector_element_type) 973 << FirstType << First->getSourceRange(); 974 } 975 if (Second && !Second->isTypeDependent()) { 976 DefaultFunctionArrayLvalueConversion(Second); 977 QualType SecondType = Second->getType(); 978 if (!SecondType->isObjCObjectPointerType()) 979 Diag(ForLoc, diag::err_collection_expr_type) 980 << SecondType << Second->getSourceRange(); 981 else if (const ObjCObjectPointerType *OPT = 982 SecondType->getAsObjCInterfacePointerType()) { 983 llvm::SmallVector<IdentifierInfo *, 4> KeyIdents; 984 IdentifierInfo* selIdent = 985 &Context.Idents.get("countByEnumeratingWithState"); 986 KeyIdents.push_back(selIdent); 987 selIdent = &Context.Idents.get("objects"); 988 KeyIdents.push_back(selIdent); 989 selIdent = &Context.Idents.get("count"); 990 KeyIdents.push_back(selIdent); 991 Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]); 992 if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) { 993 if (!IDecl->isForwardDecl() && 994 !IDecl->lookupInstanceMethod(CSelector)) { 995 // Must further look into private implementation methods. 996 if (!LookupPrivateInstanceMethod(CSelector, IDecl)) 997 Diag(ForLoc, diag::warn_collection_expr_type) 998 << SecondType << CSelector << Second->getSourceRange(); 999 } 1000 } 1001 } 1002 } 1003 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1004 ForLoc, RParenLoc)); 1005} 1006 1007StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1008 SourceLocation LabelLoc, 1009 LabelDecl *TheDecl) { 1010 getCurFunction()->setHasBranchIntoScope(); 1011 TheDecl->setUsed(); 1012 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1013} 1014 1015StmtResult 1016Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1017 Expr *E) { 1018 // Convert operand to void* 1019 if (!E->isTypeDependent()) { 1020 QualType ETy = E->getType(); 1021 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1022 AssignConvertType ConvTy = 1023 CheckSingleAssignmentConstraints(DestTy, E); 1024 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1025 return StmtError(); 1026 } 1027 1028 getCurFunction()->setHasIndirectGoto(); 1029 1030 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1031} 1032 1033StmtResult 1034Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1035 Scope *S = CurScope->getContinueParent(); 1036 if (!S) { 1037 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1038 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1039 } 1040 1041 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1042} 1043 1044StmtResult 1045Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1046 Scope *S = CurScope->getBreakParent(); 1047 if (!S) { 1048 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1049 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1050 } 1051 1052 return Owned(new (Context) BreakStmt(BreakLoc)); 1053} 1054 1055/// \brief Determine whether the given expression is a candidate for 1056/// copy elision in either a return statement or a throw expression. 1057/// 1058/// \param ReturnType If we're determining the copy elision candidate for 1059/// a return statement, this is the return type of the function. If we're 1060/// determining the copy elision candidate for a throw expression, this will 1061/// be a NULL type. 1062/// 1063/// \param E The expression being returned from the function or block, or 1064/// being thrown. 1065/// 1066/// \param AllowFunctionParameter 1067/// 1068/// \returns The NRVO candidate variable, if the return statement may use the 1069/// NRVO, or NULL if there is no such candidate. 1070const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1071 Expr *E, 1072 bool AllowFunctionParameter) { 1073 QualType ExprType = E->getType(); 1074 // - in a return statement in a function with ... 1075 // ... a class return type ... 1076 if (!ReturnType.isNull()) { 1077 if (!ReturnType->isRecordType()) 1078 return 0; 1079 // ... the same cv-unqualified type as the function return type ... 1080 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1081 return 0; 1082 } 1083 1084 // ... the expression is the name of a non-volatile automatic object 1085 // (other than a function or catch-clause parameter)) ... 1086 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1087 if (!DR) 1088 return 0; 1089 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1090 if (!VD) 1091 return 0; 1092 1093 if (VD->hasLocalStorage() && !VD->isExceptionVariable() && 1094 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1095 !VD->getType().isVolatileQualified() && 1096 ((VD->getKind() == Decl::Var) || 1097 (AllowFunctionParameter && VD->getKind() == Decl::ParmVar))) 1098 return VD; 1099 1100 return 0; 1101} 1102 1103/// \brief Perform the initialization of a potentially-movable value, which 1104/// is the result of return value. 1105/// 1106/// This routine implements C++0x [class.copy]p33, which attempts to treat 1107/// returned lvalues as rvalues in certain cases (to prefer move construction), 1108/// then falls back to treating them as lvalues if that failed. 1109ExprResult 1110Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1111 const VarDecl *NRVOCandidate, 1112 QualType ResultType, 1113 Expr *Value) { 1114 // C++0x [class.copy]p33: 1115 // When the criteria for elision of a copy operation are met or would 1116 // be met save for the fact that the source object is a function 1117 // parameter, and the object to be copied is designated by an lvalue, 1118 // overload resolution to select the constructor for the copy is first 1119 // performed as if the object were designated by an rvalue. 1120 ExprResult Res = ExprError(); 1121 if (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true)) { 1122 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1123 Value->getType(), CK_LValueToRValue, 1124 Value, VK_XValue); 1125 1126 Expr *InitExpr = &AsRvalue; 1127 InitializationKind Kind 1128 = InitializationKind::CreateCopy(Value->getLocStart(), 1129 Value->getLocStart()); 1130 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1131 1132 // [...] If overload resolution fails, or if the type of the first 1133 // parameter of the selected constructor is not an rvalue reference 1134 // to the object's type (possibly cv-qualified), overload resolution 1135 // is performed again, considering the object as an lvalue. 1136 if (Seq.getKind() != InitializationSequence::FailedSequence) { 1137 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1138 StepEnd = Seq.step_end(); 1139 Step != StepEnd; ++Step) { 1140 if (Step->Kind 1141 != InitializationSequence::SK_ConstructorInitialization) 1142 continue; 1143 1144 CXXConstructorDecl *Constructor 1145 = cast<CXXConstructorDecl>(Step->Function.Function); 1146 1147 const RValueReferenceType *RRefType 1148 = Constructor->getParamDecl(0)->getType() 1149 ->getAs<RValueReferenceType>(); 1150 1151 // If we don't meet the criteria, break out now. 1152 if (!RRefType || 1153 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1154 Context.getTypeDeclType(Constructor->getParent()))) 1155 break; 1156 1157 // Promote "AsRvalue" to the heap, since we now need this 1158 // expression node to persist. 1159 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1160 CK_LValueToRValue, Value, 0, 1161 VK_XValue); 1162 1163 // Complete type-checking the initialization of the return type 1164 // using the constructor we found. 1165 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1166 } 1167 } 1168 } 1169 1170 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1171 // above, or overload resolution failed. Either way, we need to try 1172 // (again) now with the return value expression as written. 1173 if (Res.isInvalid()) 1174 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1175 1176 return Res; 1177} 1178 1179/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1180/// 1181StmtResult 1182Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1183 // If this is the first return we've seen in the block, infer the type of 1184 // the block from it. 1185 BlockScopeInfo *CurBlock = getCurBlock(); 1186 if (CurBlock->ReturnType.isNull()) { 1187 if (RetValExp) { 1188 // Don't call UsualUnaryConversions(), since we don't want to do 1189 // integer promotions here. 1190 DefaultFunctionArrayLvalueConversion(RetValExp); 1191 CurBlock->ReturnType = RetValExp->getType(); 1192 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1193 // We have to remove a 'const' added to copied-in variable which was 1194 // part of the implementation spec. and not the actual qualifier for 1195 // the variable. 1196 if (CDRE->isConstQualAdded()) 1197 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1198 } 1199 } else 1200 CurBlock->ReturnType = Context.VoidTy; 1201 } 1202 QualType FnRetType = CurBlock->ReturnType; 1203 1204 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1205 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1206 << getCurFunctionOrMethodDecl()->getDeclName(); 1207 return StmtError(); 1208 } 1209 1210 // Otherwise, verify that this result type matches the previous one. We are 1211 // pickier with blocks than for normal functions because we don't have GCC 1212 // compatibility to worry about here. 1213 ReturnStmt *Result = 0; 1214 if (CurBlock->ReturnType->isVoidType()) { 1215 if (RetValExp) { 1216 Diag(ReturnLoc, diag::err_return_block_has_expr); 1217 RetValExp = 0; 1218 } 1219 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1220 } else if (!RetValExp) { 1221 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1222 } else { 1223 const VarDecl *NRVOCandidate = 0; 1224 1225 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1226 // we have a non-void block with an expression, continue checking 1227 1228 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1229 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1230 // function return. 1231 1232 // In C++ the return statement is handled via a copy initialization. 1233 // the C version of which boils down to CheckSingleAssignmentConstraints. 1234 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1235 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1236 FnRetType, 1237 NRVOCandidate != 0); 1238 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1239 FnRetType, RetValExp); 1240 if (Res.isInvalid()) { 1241 // FIXME: Cleanup temporaries here, anyway? 1242 return StmtError(); 1243 } 1244 1245 if (RetValExp) { 1246 CheckImplicitConversions(RetValExp, ReturnLoc); 1247 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1248 } 1249 1250 RetValExp = Res.takeAs<Expr>(); 1251 if (RetValExp) 1252 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1253 } 1254 1255 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1256 } 1257 1258 // If we need to check for the named return value optimization, save the 1259 // return statement in our scope for later processing. 1260 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1261 !CurContext->isDependentContext()) 1262 FunctionScopes.back()->Returns.push_back(Result); 1263 1264 return Owned(Result); 1265} 1266 1267StmtResult 1268Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1269 if (getCurBlock()) 1270 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1271 1272 QualType FnRetType; 1273 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1274 FnRetType = FD->getResultType(); 1275 if (FD->hasAttr<NoReturnAttr>() || 1276 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1277 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1278 << getCurFunctionOrMethodDecl()->getDeclName(); 1279 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1280 FnRetType = MD->getResultType(); 1281 else // If we don't have a function/method context, bail. 1282 return StmtError(); 1283 1284 ReturnStmt *Result = 0; 1285 if (FnRetType->isVoidType()) { 1286 if (RetValExp && !RetValExp->isTypeDependent()) { 1287 // C99 6.8.6.4p1 (ext_ since GCC warns) 1288 unsigned D = diag::ext_return_has_expr; 1289 if (RetValExp->getType()->isVoidType()) 1290 D = diag::ext_return_has_void_expr; 1291 else { 1292 IgnoredValueConversions(RetValExp); 1293 ImpCastExprToType(RetValExp, Context.VoidTy, CK_ToVoid); 1294 } 1295 1296 // return (some void expression); is legal in C++. 1297 if (D != diag::ext_return_has_void_expr || 1298 !getLangOptions().CPlusPlus) { 1299 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1300 Diag(ReturnLoc, D) 1301 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1302 << RetValExp->getSourceRange(); 1303 } 1304 1305 CheckImplicitConversions(RetValExp, ReturnLoc); 1306 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1307 } 1308 1309 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1310 } else if (!RetValExp && !FnRetType->isDependentType()) { 1311 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1312 // C99 6.8.6.4p1 (ext_ since GCC warns) 1313 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1314 1315 if (FunctionDecl *FD = getCurFunctionDecl()) 1316 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1317 else 1318 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1319 Result = new (Context) ReturnStmt(ReturnLoc); 1320 } else { 1321 const VarDecl *NRVOCandidate = 0; 1322 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1323 // we have a non-void function with an expression, continue checking 1324 1325 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1326 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1327 // function return. 1328 1329 // In C++ the return statement is handled via a copy initialization. 1330 // the C version of which boils down to CheckSingleAssignmentConstraints. 1331 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1332 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1333 FnRetType, 1334 NRVOCandidate != 0); 1335 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1336 FnRetType, RetValExp); 1337 if (Res.isInvalid()) { 1338 // FIXME: Cleanup temporaries here, anyway? 1339 return StmtError(); 1340 } 1341 1342 RetValExp = Res.takeAs<Expr>(); 1343 if (RetValExp) 1344 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1345 } 1346 1347 if (RetValExp) { 1348 CheckImplicitConversions(RetValExp, ReturnLoc); 1349 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1350 } 1351 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1352 } 1353 1354 // If we need to check for the named return value optimization, save the 1355 // return statement in our scope for later processing. 1356 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1357 !CurContext->isDependentContext()) 1358 FunctionScopes.back()->Returns.push_back(Result); 1359 1360 return Owned(Result); 1361} 1362 1363/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1364/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1365/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1366/// provide a strong guidance to not use it. 1367/// 1368/// This method checks to see if the argument is an acceptable l-value and 1369/// returns false if it is a case we can handle. 1370static bool CheckAsmLValue(const Expr *E, Sema &S) { 1371 // Type dependent expressions will be checked during instantiation. 1372 if (E->isTypeDependent()) 1373 return false; 1374 1375 if (E->isLValue()) 1376 return false; // Cool, this is an lvalue. 1377 1378 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1379 // are supposed to allow. 1380 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1381 if (E != E2 && E2->isLValue()) { 1382 if (!S.getLangOptions().HeinousExtensions) 1383 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1384 << E->getSourceRange(); 1385 else 1386 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1387 << E->getSourceRange(); 1388 // Accept, even if we emitted an error diagnostic. 1389 return false; 1390 } 1391 1392 // None of the above, just randomly invalid non-lvalue. 1393 return true; 1394} 1395 1396/// isOperandMentioned - Return true if the specified operand # is mentioned 1397/// anywhere in the decomposed asm string. 1398static bool isOperandMentioned(unsigned OpNo, 1399 llvm::ArrayRef<AsmStmt::AsmStringPiece> AsmStrPieces) { 1400 for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) { 1401 const AsmStmt::AsmStringPiece &Piece = AsmStrPieces[p]; 1402 if (!Piece.isOperand()) continue; 1403 1404 // If this is a reference to the input and if the input was the smaller 1405 // one, then we have to reject this asm. 1406 if (Piece.getOperandNo() == OpNo) 1407 return true; 1408 } 1409 1410 return false; 1411} 1412 1413StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, bool IsSimple, 1414 bool IsVolatile, unsigned NumOutputs, 1415 unsigned NumInputs, IdentifierInfo **Names, 1416 MultiExprArg constraints, MultiExprArg exprs, 1417 Expr *asmString, MultiExprArg clobbers, 1418 SourceLocation RParenLoc, bool MSAsm) { 1419 unsigned NumClobbers = clobbers.size(); 1420 StringLiteral **Constraints = 1421 reinterpret_cast<StringLiteral**>(constraints.get()); 1422 Expr **Exprs = exprs.get(); 1423 StringLiteral *AsmString = cast<StringLiteral>(asmString); 1424 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1425 1426 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1427 1428 // The parser verifies that there is a string literal here. 1429 if (AsmString->isWide()) 1430 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1431 << AsmString->getSourceRange()); 1432 1433 for (unsigned i = 0; i != NumOutputs; i++) { 1434 StringLiteral *Literal = Constraints[i]; 1435 if (Literal->isWide()) 1436 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1437 << Literal->getSourceRange()); 1438 1439 llvm::StringRef OutputName; 1440 if (Names[i]) 1441 OutputName = Names[i]->getName(); 1442 1443 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1444 if (!Context.Target.validateOutputConstraint(Info)) 1445 return StmtError(Diag(Literal->getLocStart(), 1446 diag::err_asm_invalid_output_constraint) 1447 << Info.getConstraintStr()); 1448 1449 // Check that the output exprs are valid lvalues. 1450 Expr *OutputExpr = Exprs[i]; 1451 if (CheckAsmLValue(OutputExpr, *this)) { 1452 return StmtError(Diag(OutputExpr->getLocStart(), 1453 diag::err_asm_invalid_lvalue_in_output) 1454 << OutputExpr->getSourceRange()); 1455 } 1456 1457 OutputConstraintInfos.push_back(Info); 1458 } 1459 1460 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1461 1462 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1463 StringLiteral *Literal = Constraints[i]; 1464 if (Literal->isWide()) 1465 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1466 << Literal->getSourceRange()); 1467 1468 llvm::StringRef InputName; 1469 if (Names[i]) 1470 InputName = Names[i]->getName(); 1471 1472 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1473 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1474 NumOutputs, Info)) { 1475 return StmtError(Diag(Literal->getLocStart(), 1476 diag::err_asm_invalid_input_constraint) 1477 << Info.getConstraintStr()); 1478 } 1479 1480 Expr *InputExpr = Exprs[i]; 1481 1482 // Only allow void types for memory constraints. 1483 if (Info.allowsMemory() && !Info.allowsRegister()) { 1484 if (CheckAsmLValue(InputExpr, *this)) 1485 return StmtError(Diag(InputExpr->getLocStart(), 1486 diag::err_asm_invalid_lvalue_in_input) 1487 << Info.getConstraintStr() 1488 << InputExpr->getSourceRange()); 1489 } 1490 1491 if (Info.allowsRegister()) { 1492 if (InputExpr->getType()->isVoidType()) { 1493 return StmtError(Diag(InputExpr->getLocStart(), 1494 diag::err_asm_invalid_type_in_input) 1495 << InputExpr->getType() << Info.getConstraintStr() 1496 << InputExpr->getSourceRange()); 1497 } 1498 } 1499 1500 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1501 1502 InputConstraintInfos.push_back(Info); 1503 } 1504 1505 // Check that the clobbers are valid. 1506 for (unsigned i = 0; i != NumClobbers; i++) { 1507 StringLiteral *Literal = Clobbers[i]; 1508 if (Literal->isWide()) 1509 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1510 << Literal->getSourceRange()); 1511 1512 llvm::StringRef Clobber = Literal->getString(); 1513 1514 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1515 return StmtError(Diag(Literal->getLocStart(), 1516 diag::err_asm_unknown_register_name) << Clobber); 1517 } 1518 1519 AsmStmt *NS = 1520 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1521 NumOutputs, NumInputs, Names, Constraints, Exprs, 1522 AsmString, NumClobbers, Clobbers, RParenLoc); 1523 // Validate the asm string, ensuring it makes sense given the operands we 1524 // have. 1525 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1526 unsigned DiagOffs; 1527 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1528 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1529 << AsmString->getSourceRange(); 1530 return StmtError(); 1531 } 1532 1533 // Validate tied input operands for type mismatches. 1534 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1535 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1536 1537 // If this is a tied constraint, verify that the output and input have 1538 // either exactly the same type, or that they are int/ptr operands with the 1539 // same size (int/long, int*/long, are ok etc). 1540 if (!Info.hasTiedOperand()) continue; 1541 1542 unsigned TiedTo = Info.getTiedOperand(); 1543 unsigned InputOpNo = i+NumOutputs; 1544 Expr *OutputExpr = Exprs[TiedTo]; 1545 Expr *InputExpr = Exprs[InputOpNo]; 1546 QualType InTy = InputExpr->getType(); 1547 QualType OutTy = OutputExpr->getType(); 1548 if (Context.hasSameType(InTy, OutTy)) 1549 continue; // All types can be tied to themselves. 1550 1551 // Decide if the input and output are in the same domain (integer/ptr or 1552 // floating point. 1553 enum AsmDomain { 1554 AD_Int, AD_FP, AD_Other 1555 } InputDomain, OutputDomain; 1556 1557 if (InTy->isIntegerType() || InTy->isPointerType()) 1558 InputDomain = AD_Int; 1559 else if (InTy->isRealFloatingType()) 1560 InputDomain = AD_FP; 1561 else 1562 InputDomain = AD_Other; 1563 1564 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1565 OutputDomain = AD_Int; 1566 else if (OutTy->isRealFloatingType()) 1567 OutputDomain = AD_FP; 1568 else 1569 OutputDomain = AD_Other; 1570 1571 // They are ok if they are the same size and in the same domain. This 1572 // allows tying things like: 1573 // void* to int* 1574 // void* to int if they are the same size. 1575 // double to long double if they are the same size. 1576 // 1577 uint64_t OutSize = Context.getTypeSize(OutTy); 1578 uint64_t InSize = Context.getTypeSize(InTy); 1579 if (OutSize == InSize && InputDomain == OutputDomain && 1580 InputDomain != AD_Other) 1581 continue; 1582 1583 // If the smaller input/output operand is not mentioned in the asm string, 1584 // then we can promote the smaller one to a larger input and the asm string 1585 // won't notice. 1586 bool SmallerValueMentioned = false; 1587 1588 // If this is a reference to the input and if the input was the smaller 1589 // one, then we have to reject this asm. 1590 if (isOperandMentioned(InputOpNo, Pieces)) { 1591 // This is a use in the asm string of the smaller operand. Since we 1592 // codegen this by promoting to a wider value, the asm will get printed 1593 // "wrong". 1594 SmallerValueMentioned |= InSize < OutSize; 1595 } 1596 if (isOperandMentioned(TiedTo, Pieces)) { 1597 // If this is a reference to the output, and if the output is the larger 1598 // value, then it's ok because we'll promote the input to the larger type. 1599 SmallerValueMentioned |= OutSize < InSize; 1600 } 1601 1602 // If the smaller value wasn't mentioned in the asm string, and if the 1603 // output was a register, just extend the shorter one to the size of the 1604 // larger one. 1605 if (!SmallerValueMentioned && InputDomain != AD_Other && 1606 OutputConstraintInfos[TiedTo].allowsRegister()) 1607 continue; 1608 1609 // Either both of the operands were mentioned or the smaller one was 1610 // mentioned. One more special case that we'll allow: if the tied input is 1611 // integer, unmentioned, and is a constant, then we'll allow truncating it 1612 // down to the size of the destination. 1613 if (InputDomain == AD_Int && OutputDomain == AD_Int && 1614 !isOperandMentioned(InputOpNo, Pieces) && 1615 InputExpr->isEvaluatable(Context)) { 1616 ImpCastExprToType(InputExpr, OutTy, CK_IntegralCast); 1617 Exprs[InputOpNo] = InputExpr; 1618 NS->setInputExpr(i, InputExpr); 1619 continue; 1620 } 1621 1622 Diag(InputExpr->getLocStart(), 1623 diag::err_asm_tying_incompatible_types) 1624 << InTy << OutTy << OutputExpr->getSourceRange() 1625 << InputExpr->getSourceRange(); 1626 return StmtError(); 1627 } 1628 1629 return Owned(NS); 1630} 1631 1632StmtResult 1633Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1634 SourceLocation RParen, Decl *Parm, 1635 Stmt *Body) { 1636 VarDecl *Var = cast_or_null<VarDecl>(Parm); 1637 if (Var && Var->isInvalidDecl()) 1638 return StmtError(); 1639 1640 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 1641} 1642 1643StmtResult 1644Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 1645 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 1646} 1647 1648StmtResult 1649Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 1650 MultiStmtArg CatchStmts, Stmt *Finally) { 1651 if (!getLangOptions().ObjCExceptions) 1652 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 1653 1654 getCurFunction()->setHasBranchProtectedScope(); 1655 unsigned NumCatchStmts = CatchStmts.size(); 1656 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 1657 CatchStmts.release(), 1658 NumCatchStmts, 1659 Finally)); 1660} 1661 1662StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 1663 Expr *Throw) { 1664 if (Throw) { 1665 DefaultLvalueConversion(Throw); 1666 1667 QualType ThrowType = Throw->getType(); 1668 // Make sure the expression type is an ObjC pointer or "void *". 1669 if (!ThrowType->isDependentType() && 1670 !ThrowType->isObjCObjectPointerType()) { 1671 const PointerType *PT = ThrowType->getAs<PointerType>(); 1672 if (!PT || !PT->getPointeeType()->isVoidType()) 1673 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1674 << Throw->getType() << Throw->getSourceRange()); 1675 } 1676 } 1677 1678 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 1679} 1680 1681StmtResult 1682Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 1683 Scope *CurScope) { 1684 if (!getLangOptions().ObjCExceptions) 1685 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 1686 1687 if (!Throw) { 1688 // @throw without an expression designates a rethrow (which much occur 1689 // in the context of an @catch clause). 1690 Scope *AtCatchParent = CurScope; 1691 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1692 AtCatchParent = AtCatchParent->getParent(); 1693 if (!AtCatchParent) 1694 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1695 } 1696 1697 return BuildObjCAtThrowStmt(AtLoc, Throw); 1698} 1699 1700StmtResult 1701Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 1702 Stmt *SyncBody) { 1703 getCurFunction()->setHasBranchProtectedScope(); 1704 1705 DefaultLvalueConversion(SyncExpr); 1706 1707 // Make sure the expression type is an ObjC pointer or "void *". 1708 if (!SyncExpr->getType()->isDependentType() && 1709 !SyncExpr->getType()->isObjCObjectPointerType()) { 1710 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1711 if (!PT || !PT->getPointeeType()->isVoidType()) 1712 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1713 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1714 } 1715 1716 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 1717} 1718 1719/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1720/// and creates a proper catch handler from them. 1721StmtResult 1722Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 1723 Stmt *HandlerBlock) { 1724 // There's nothing to test that ActOnExceptionDecl didn't already test. 1725 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1726 cast_or_null<VarDecl>(ExDecl), 1727 HandlerBlock)); 1728} 1729 1730namespace { 1731 1732class TypeWithHandler { 1733 QualType t; 1734 CXXCatchStmt *stmt; 1735public: 1736 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1737 : t(type), stmt(statement) {} 1738 1739 // An arbitrary order is fine as long as it places identical 1740 // types next to each other. 1741 bool operator<(const TypeWithHandler &y) const { 1742 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1743 return true; 1744 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1745 return false; 1746 else 1747 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1748 } 1749 1750 bool operator==(const TypeWithHandler& other) const { 1751 return t == other.t; 1752 } 1753 1754 CXXCatchStmt *getCatchStmt() const { return stmt; } 1755 SourceLocation getTypeSpecStartLoc() const { 1756 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1757 } 1758}; 1759 1760} 1761 1762/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1763/// handlers and creates a try statement from them. 1764StmtResult 1765Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 1766 MultiStmtArg RawHandlers) { 1767 // Don't report an error if 'try' is used in system headers. 1768 if (!getLangOptions().CXXExceptions && 1769 !getSourceManager().isInSystemHeader(TryLoc)) 1770 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 1771 1772 unsigned NumHandlers = RawHandlers.size(); 1773 assert(NumHandlers > 0 && 1774 "The parser shouldn't call this if there are no handlers."); 1775 Stmt **Handlers = RawHandlers.get(); 1776 1777 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1778 1779 for (unsigned i = 0; i < NumHandlers; ++i) { 1780 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1781 if (!Handler->getExceptionDecl()) { 1782 if (i < NumHandlers - 1) 1783 return StmtError(Diag(Handler->getLocStart(), 1784 diag::err_early_catch_all)); 1785 1786 continue; 1787 } 1788 1789 const QualType CaughtType = Handler->getCaughtType(); 1790 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1791 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1792 } 1793 1794 // Detect handlers for the same type as an earlier one. 1795 if (NumHandlers > 1) { 1796 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1797 1798 TypeWithHandler prev = TypesWithHandlers[0]; 1799 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1800 TypeWithHandler curr = TypesWithHandlers[i]; 1801 1802 if (curr == prev) { 1803 Diag(curr.getTypeSpecStartLoc(), 1804 diag::warn_exception_caught_by_earlier_handler) 1805 << curr.getCatchStmt()->getCaughtType().getAsString(); 1806 Diag(prev.getTypeSpecStartLoc(), 1807 diag::note_previous_exception_handler) 1808 << prev.getCatchStmt()->getCaughtType().getAsString(); 1809 } 1810 1811 prev = curr; 1812 } 1813 } 1814 1815 getCurFunction()->setHasBranchProtectedScope(); 1816 1817 // FIXME: We should detect handlers that cannot catch anything because an 1818 // earlier handler catches a superclass. Need to find a method that is not 1819 // quadratic for this. 1820 // Neither of these are explicitly forbidden, but every compiler detects them 1821 // and warns. 1822 1823 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 1824 Handlers, NumHandlers)); 1825} 1826