SemaStmt.cpp revision 218893
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/STLExtras.h" 29#include "llvm/ADT/SmallVector.h" 30using namespace clang; 31using namespace sema; 32 33StmtResult Sema::ActOnExprStmt(FullExprArg expr) { 34 Expr *E = expr.get(); 35 if (!E) // FIXME: FullExprArg has no error state? 36 return StmtError(); 37 38 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 39 // void expression for its side effects. Conversion to void allows any 40 // operand, even incomplete types. 41 42 // Same thing in for stmt first clause (when expr) and third clause. 43 return Owned(static_cast<Stmt*>(E)); 44} 45 46 47StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, bool LeadingEmptyMacro) { 48 return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacro)); 49} 50 51StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, SourceLocation StartLoc, 52 SourceLocation EndLoc) { 53 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 54 55 // If we have an invalid decl, just return an error. 56 if (DG.isNull()) return StmtError(); 57 58 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 59} 60 61void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 62 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 63 64 // If we have an invalid decl, just return. 65 if (DG.isNull() || !DG.isSingleDecl()) return; 66 // suppress any potential 'unused variable' warning. 67 DG.getSingleDecl()->setUsed(); 68} 69 70void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 71 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 72 return DiagnoseUnusedExprResult(Label->getSubStmt()); 73 74 const Expr *E = dyn_cast_or_null<Expr>(S); 75 if (!E) 76 return; 77 78 if (E->isBoundMemberFunction(Context)) { 79 Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func) 80 << E->getSourceRange(); 81 return; 82 } 83 84 SourceLocation Loc; 85 SourceRange R1, R2; 86 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 87 return; 88 89 // Okay, we have an unused result. Depending on what the base expression is, 90 // we might want to make a more specific diagnostic. Check for one of these 91 // cases now. 92 unsigned DiagID = diag::warn_unused_expr; 93 if (const ExprWithCleanups *Temps = dyn_cast<ExprWithCleanups>(E)) 94 E = Temps->getSubExpr(); 95 96 E = E->IgnoreParenImpCasts(); 97 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 98 if (E->getType()->isVoidType()) 99 return; 100 101 // If the callee has attribute pure, const, or warn_unused_result, warn with 102 // a more specific message to make it clear what is happening. 103 if (const Decl *FD = CE->getCalleeDecl()) { 104 if (FD->getAttr<WarnUnusedResultAttr>()) { 105 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 106 return; 107 } 108 if (FD->getAttr<PureAttr>()) { 109 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 110 return; 111 } 112 if (FD->getAttr<ConstAttr>()) { 113 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 114 return; 115 } 116 } 117 } else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) { 118 const ObjCMethodDecl *MD = ME->getMethodDecl(); 119 if (MD && MD->getAttr<WarnUnusedResultAttr>()) { 120 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 121 return; 122 } 123 } else if (isa<ObjCPropertyRefExpr>(E)) { 124 DiagID = diag::warn_unused_property_expr; 125 } else if (const CXXFunctionalCastExpr *FC 126 = dyn_cast<CXXFunctionalCastExpr>(E)) { 127 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 128 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 129 return; 130 } 131 // Diagnose "(void*) blah" as a typo for "(void) blah". 132 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 133 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 134 QualType T = TI->getType(); 135 136 // We really do want to use the non-canonical type here. 137 if (T == Context.VoidPtrTy) { 138 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 139 140 Diag(Loc, diag::warn_unused_voidptr) 141 << FixItHint::CreateRemoval(TL.getStarLoc()); 142 return; 143 } 144 } 145 146 DiagRuntimeBehavior(Loc, PDiag(DiagID) << R1 << R2); 147} 148 149StmtResult 150Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 151 MultiStmtArg elts, bool isStmtExpr) { 152 unsigned NumElts = elts.size(); 153 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 154 // If we're in C89 mode, check that we don't have any decls after stmts. If 155 // so, emit an extension diagnostic. 156 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 157 // Note that __extension__ can be around a decl. 158 unsigned i = 0; 159 // Skip over all declarations. 160 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 161 /*empty*/; 162 163 // We found the end of the list or a statement. Scan for another declstmt. 164 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 165 /*empty*/; 166 167 if (i != NumElts) { 168 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 169 Diag(D->getLocation(), diag::ext_mixed_decls_code); 170 } 171 } 172 // Warn about unused expressions in statements. 173 for (unsigned i = 0; i != NumElts; ++i) { 174 // Ignore statements that are last in a statement expression. 175 if (isStmtExpr && i == NumElts - 1) 176 continue; 177 178 DiagnoseUnusedExprResult(Elts[i]); 179 } 180 181 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 182} 183 184StmtResult 185Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 186 SourceLocation DotDotDotLoc, Expr *RHSVal, 187 SourceLocation ColonLoc) { 188 assert((LHSVal != 0) && "missing expression in case statement"); 189 190 // C99 6.8.4.2p3: The expression shall be an integer constant. 191 // However, GCC allows any evaluatable integer expression. 192 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 193 VerifyIntegerConstantExpression(LHSVal)) 194 return StmtError(); 195 196 // GCC extension: The expression shall be an integer constant. 197 198 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 199 VerifyIntegerConstantExpression(RHSVal)) { 200 RHSVal = 0; // Recover by just forgetting about it. 201 } 202 203 if (getCurFunction()->SwitchStack.empty()) { 204 Diag(CaseLoc, diag::err_case_not_in_switch); 205 return StmtError(); 206 } 207 208 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 209 ColonLoc); 210 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 211 return Owned(CS); 212} 213 214/// ActOnCaseStmtBody - This installs a statement as the body of a case. 215void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 216 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 217 CS->setSubStmt(SubStmt); 218} 219 220StmtResult 221Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 222 Stmt *SubStmt, Scope *CurScope) { 223 if (getCurFunction()->SwitchStack.empty()) { 224 Diag(DefaultLoc, diag::err_default_not_in_switch); 225 return Owned(SubStmt); 226 } 227 228 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 229 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 230 return Owned(DS); 231} 232 233StmtResult 234Sema::ActOnLabelStmt(SourceLocation IdentLoc, LabelDecl *TheDecl, 235 SourceLocation ColonLoc, Stmt *SubStmt) { 236 237 // If the label was multiply defined, reject it now. 238 if (TheDecl->getStmt()) { 239 Diag(IdentLoc, diag::err_redefinition_of_label) << TheDecl->getDeclName(); 240 Diag(TheDecl->getLocation(), diag::note_previous_definition); 241 return Owned(SubStmt); 242 } 243 244 // Otherwise, things are good. Fill in the declaration and return it. 245 TheDecl->setLocation(IdentLoc); 246 247 LabelStmt *LS = new (Context) LabelStmt(IdentLoc, TheDecl, SubStmt); 248 TheDecl->setStmt(LS); 249 TheDecl->setLocation(IdentLoc); 250 return Owned(LS); 251} 252 253StmtResult 254Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 255 Stmt *thenStmt, SourceLocation ElseLoc, 256 Stmt *elseStmt) { 257 ExprResult CondResult(CondVal.release()); 258 259 VarDecl *ConditionVar = 0; 260 if (CondVar) { 261 ConditionVar = cast<VarDecl>(CondVar); 262 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 263 if (CondResult.isInvalid()) 264 return StmtError(); 265 } 266 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 267 if (!ConditionExpr) 268 return StmtError(); 269 270 DiagnoseUnusedExprResult(thenStmt); 271 272 // Warn if the if block has a null body without an else value. 273 // this helps prevent bugs due to typos, such as 274 // if (condition); 275 // do_stuff(); 276 // 277 if (!elseStmt) { 278 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 279 // But do not warn if the body is a macro that expands to nothing, e.g: 280 // 281 // #define CALL(x) 282 // if (condition) 283 // CALL(0); 284 // 285 if (!stmt->hasLeadingEmptyMacro()) 286 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 287 } 288 289 DiagnoseUnusedExprResult(elseStmt); 290 291 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 292 thenStmt, ElseLoc, elseStmt)); 293} 294 295/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 296/// the specified width and sign. If an overflow occurs, detect it and emit 297/// the specified diagnostic. 298void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 299 unsigned NewWidth, bool NewSign, 300 SourceLocation Loc, 301 unsigned DiagID) { 302 // Perform a conversion to the promoted condition type if needed. 303 if (NewWidth > Val.getBitWidth()) { 304 // If this is an extension, just do it. 305 Val = Val.extend(NewWidth); 306 Val.setIsSigned(NewSign); 307 308 // If the input was signed and negative and the output is 309 // unsigned, don't bother to warn: this is implementation-defined 310 // behavior. 311 // FIXME: Introduce a second, default-ignored warning for this case? 312 } else if (NewWidth < Val.getBitWidth()) { 313 // If this is a truncation, check for overflow. 314 llvm::APSInt ConvVal(Val); 315 ConvVal = ConvVal.trunc(NewWidth); 316 ConvVal.setIsSigned(NewSign); 317 ConvVal = ConvVal.extend(Val.getBitWidth()); 318 ConvVal.setIsSigned(Val.isSigned()); 319 if (ConvVal != Val) 320 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 321 322 // Regardless of whether a diagnostic was emitted, really do the 323 // truncation. 324 Val = Val.trunc(NewWidth); 325 Val.setIsSigned(NewSign); 326 } else if (NewSign != Val.isSigned()) { 327 // Convert the sign to match the sign of the condition. This can cause 328 // overflow as well: unsigned(INTMIN) 329 // We don't diagnose this overflow, because it is implementation-defined 330 // behavior. 331 // FIXME: Introduce a second, default-ignored warning for this case? 332 llvm::APSInt OldVal(Val); 333 Val.setIsSigned(NewSign); 334 } 335} 336 337namespace { 338 struct CaseCompareFunctor { 339 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 340 const llvm::APSInt &RHS) { 341 return LHS.first < RHS; 342 } 343 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 344 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 345 return LHS.first < RHS.first; 346 } 347 bool operator()(const llvm::APSInt &LHS, 348 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 349 return LHS < RHS.first; 350 } 351 }; 352} 353 354/// CmpCaseVals - Comparison predicate for sorting case values. 355/// 356static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 357 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 358 if (lhs.first < rhs.first) 359 return true; 360 361 if (lhs.first == rhs.first && 362 lhs.second->getCaseLoc().getRawEncoding() 363 < rhs.second->getCaseLoc().getRawEncoding()) 364 return true; 365 return false; 366} 367 368/// CmpEnumVals - Comparison predicate for sorting enumeration values. 369/// 370static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 371 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 372{ 373 return lhs.first < rhs.first; 374} 375 376/// EqEnumVals - Comparison preficate for uniqing enumeration values. 377/// 378static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 379 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 380{ 381 return lhs.first == rhs.first; 382} 383 384/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 385/// potentially integral-promoted expression @p expr. 386static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 387 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 388 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 389 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 390 if (TypeBeforePromotion->isIntegralOrEnumerationType()) { 391 return TypeBeforePromotion; 392 } 393 } 394 return expr->getType(); 395} 396 397StmtResult 398Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 399 Decl *CondVar) { 400 ExprResult CondResult; 401 402 VarDecl *ConditionVar = 0; 403 if (CondVar) { 404 ConditionVar = cast<VarDecl>(CondVar); 405 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 406 if (CondResult.isInvalid()) 407 return StmtError(); 408 409 Cond = CondResult.release(); 410 } 411 412 if (!Cond) 413 return StmtError(); 414 415 CondResult 416 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 417 PDiag(diag::err_typecheck_statement_requires_integer), 418 PDiag(diag::err_switch_incomplete_class_type) 419 << Cond->getSourceRange(), 420 PDiag(diag::err_switch_explicit_conversion), 421 PDiag(diag::note_switch_conversion), 422 PDiag(diag::err_switch_multiple_conversions), 423 PDiag(diag::note_switch_conversion), 424 PDiag(0)); 425 if (CondResult.isInvalid()) return StmtError(); 426 Cond = CondResult.take(); 427 428 if (!CondVar) { 429 CheckImplicitConversions(Cond, SwitchLoc); 430 CondResult = MaybeCreateExprWithCleanups(Cond); 431 if (CondResult.isInvalid()) 432 return StmtError(); 433 Cond = CondResult.take(); 434 } 435 436 getCurFunction()->setHasBranchIntoScope(); 437 438 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 439 getCurFunction()->SwitchStack.push_back(SS); 440 return Owned(SS); 441} 442 443static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 444 if (Val.getBitWidth() < BitWidth) 445 Val = Val.extend(BitWidth); 446 else if (Val.getBitWidth() > BitWidth) 447 Val = Val.trunc(BitWidth); 448 Val.setIsSigned(IsSigned); 449} 450 451StmtResult 452Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 453 Stmt *BodyStmt) { 454 SwitchStmt *SS = cast<SwitchStmt>(Switch); 455 assert(SS == getCurFunction()->SwitchStack.back() && 456 "switch stack missing push/pop!"); 457 458 SS->setBody(BodyStmt, SwitchLoc); 459 getCurFunction()->SwitchStack.pop_back(); 460 461 if (SS->getCond() == 0) 462 return StmtError(); 463 464 Expr *CondExpr = SS->getCond(); 465 Expr *CondExprBeforePromotion = CondExpr; 466 QualType CondTypeBeforePromotion = 467 GetTypeBeforeIntegralPromotion(CondExpr); 468 469 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 470 UsualUnaryConversions(CondExpr); 471 QualType CondType = CondExpr->getType(); 472 SS->setCond(CondExpr); 473 474 // C++ 6.4.2.p2: 475 // Integral promotions are performed (on the switch condition). 476 // 477 // A case value unrepresentable by the original switch condition 478 // type (before the promotion) doesn't make sense, even when it can 479 // be represented by the promoted type. Therefore we need to find 480 // the pre-promotion type of the switch condition. 481 if (!CondExpr->isTypeDependent()) { 482 // We have already converted the expression to an integral or enumeration 483 // type, when we started the switch statement. If we don't have an 484 // appropriate type now, just return an error. 485 if (!CondType->isIntegralOrEnumerationType()) 486 return StmtError(); 487 488 if (CondExpr->isKnownToHaveBooleanValue()) { 489 // switch(bool_expr) {...} is often a programmer error, e.g. 490 // switch(n && mask) { ... } // Doh - should be "n & mask". 491 // One can always use an if statement instead of switch(bool_expr). 492 Diag(SwitchLoc, diag::warn_bool_switch_condition) 493 << CondExpr->getSourceRange(); 494 } 495 } 496 497 // Get the bitwidth of the switched-on value before promotions. We must 498 // convert the integer case values to this width before comparison. 499 bool HasDependentValue 500 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 501 unsigned CondWidth 502 = HasDependentValue? 0 503 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 504 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 505 506 // Accumulate all of the case values in a vector so that we can sort them 507 // and detect duplicates. This vector contains the APInt for the case after 508 // it has been converted to the condition type. 509 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 510 CaseValsTy CaseVals; 511 512 // Keep track of any GNU case ranges we see. The APSInt is the low value. 513 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 514 CaseRangesTy CaseRanges; 515 516 DefaultStmt *TheDefaultStmt = 0; 517 518 bool CaseListIsErroneous = false; 519 520 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 521 SC = SC->getNextSwitchCase()) { 522 523 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 524 if (TheDefaultStmt) { 525 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 526 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 527 528 // FIXME: Remove the default statement from the switch block so that 529 // we'll return a valid AST. This requires recursing down the AST and 530 // finding it, not something we are set up to do right now. For now, 531 // just lop the entire switch stmt out of the AST. 532 CaseListIsErroneous = true; 533 } 534 TheDefaultStmt = DS; 535 536 } else { 537 CaseStmt *CS = cast<CaseStmt>(SC); 538 539 // We already verified that the expression has a i-c-e value (C99 540 // 6.8.4.2p3) - get that value now. 541 Expr *Lo = CS->getLHS(); 542 543 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 544 HasDependentValue = true; 545 break; 546 } 547 548 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 549 550 // Convert the value to the same width/sign as the condition. 551 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 552 Lo->getLocStart(), 553 diag::warn_case_value_overflow); 554 555 // If the LHS is not the same type as the condition, insert an implicit 556 // cast. 557 ImpCastExprToType(Lo, CondType, CK_IntegralCast); 558 CS->setLHS(Lo); 559 560 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 561 if (CS->getRHS()) { 562 if (CS->getRHS()->isTypeDependent() || 563 CS->getRHS()->isValueDependent()) { 564 HasDependentValue = true; 565 break; 566 } 567 CaseRanges.push_back(std::make_pair(LoVal, CS)); 568 } else 569 CaseVals.push_back(std::make_pair(LoVal, CS)); 570 } 571 } 572 573 if (!HasDependentValue) { 574 // If we don't have a default statement, check whether the 575 // condition is constant. 576 llvm::APSInt ConstantCondValue; 577 bool HasConstantCond = false; 578 bool ShouldCheckConstantCond = false; 579 if (!HasDependentValue && !TheDefaultStmt) { 580 Expr::EvalResult Result; 581 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 582 if (HasConstantCond) { 583 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 584 ConstantCondValue = Result.Val.getInt(); 585 ShouldCheckConstantCond = true; 586 587 assert(ConstantCondValue.getBitWidth() == CondWidth && 588 ConstantCondValue.isSigned() == CondIsSigned); 589 } 590 } 591 592 // Sort all the scalar case values so we can easily detect duplicates. 593 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 594 595 if (!CaseVals.empty()) { 596 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 597 if (ShouldCheckConstantCond && 598 CaseVals[i].first == ConstantCondValue) 599 ShouldCheckConstantCond = false; 600 601 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 602 // If we have a duplicate, report it. 603 Diag(CaseVals[i].second->getLHS()->getLocStart(), 604 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 605 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 606 diag::note_duplicate_case_prev); 607 // FIXME: We really want to remove the bogus case stmt from the 608 // substmt, but we have no way to do this right now. 609 CaseListIsErroneous = true; 610 } 611 } 612 } 613 614 // Detect duplicate case ranges, which usually don't exist at all in 615 // the first place. 616 if (!CaseRanges.empty()) { 617 // Sort all the case ranges by their low value so we can easily detect 618 // overlaps between ranges. 619 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 620 621 // Scan the ranges, computing the high values and removing empty ranges. 622 std::vector<llvm::APSInt> HiVals; 623 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 624 llvm::APSInt &LoVal = CaseRanges[i].first; 625 CaseStmt *CR = CaseRanges[i].second; 626 Expr *Hi = CR->getRHS(); 627 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 628 629 // Convert the value to the same width/sign as the condition. 630 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 631 Hi->getLocStart(), 632 diag::warn_case_value_overflow); 633 634 // If the LHS is not the same type as the condition, insert an implicit 635 // cast. 636 ImpCastExprToType(Hi, CondType, CK_IntegralCast); 637 CR->setRHS(Hi); 638 639 // If the low value is bigger than the high value, the case is empty. 640 if (LoVal > HiVal) { 641 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 642 << SourceRange(CR->getLHS()->getLocStart(), 643 Hi->getLocEnd()); 644 CaseRanges.erase(CaseRanges.begin()+i); 645 --i, --e; 646 continue; 647 } 648 649 if (ShouldCheckConstantCond && 650 LoVal <= ConstantCondValue && 651 ConstantCondValue <= HiVal) 652 ShouldCheckConstantCond = false; 653 654 HiVals.push_back(HiVal); 655 } 656 657 // Rescan the ranges, looking for overlap with singleton values and other 658 // ranges. Since the range list is sorted, we only need to compare case 659 // ranges with their neighbors. 660 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 661 llvm::APSInt &CRLo = CaseRanges[i].first; 662 llvm::APSInt &CRHi = HiVals[i]; 663 CaseStmt *CR = CaseRanges[i].second; 664 665 // Check to see whether the case range overlaps with any 666 // singleton cases. 667 CaseStmt *OverlapStmt = 0; 668 llvm::APSInt OverlapVal(32); 669 670 // Find the smallest value >= the lower bound. If I is in the 671 // case range, then we have overlap. 672 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 673 CaseVals.end(), CRLo, 674 CaseCompareFunctor()); 675 if (I != CaseVals.end() && I->first < CRHi) { 676 OverlapVal = I->first; // Found overlap with scalar. 677 OverlapStmt = I->second; 678 } 679 680 // Find the smallest value bigger than the upper bound. 681 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 682 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 683 OverlapVal = (I-1)->first; // Found overlap with scalar. 684 OverlapStmt = (I-1)->second; 685 } 686 687 // Check to see if this case stmt overlaps with the subsequent 688 // case range. 689 if (i && CRLo <= HiVals[i-1]) { 690 OverlapVal = HiVals[i-1]; // Found overlap with range. 691 OverlapStmt = CaseRanges[i-1].second; 692 } 693 694 if (OverlapStmt) { 695 // If we have a duplicate, report it. 696 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 697 << OverlapVal.toString(10); 698 Diag(OverlapStmt->getLHS()->getLocStart(), 699 diag::note_duplicate_case_prev); 700 // FIXME: We really want to remove the bogus case stmt from the 701 // substmt, but we have no way to do this right now. 702 CaseListIsErroneous = true; 703 } 704 } 705 } 706 707 // Complain if we have a constant condition and we didn't find a match. 708 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 709 // TODO: it would be nice if we printed enums as enums, chars as 710 // chars, etc. 711 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 712 << ConstantCondValue.toString(10) 713 << CondExpr->getSourceRange(); 714 } 715 716 // Check to see if switch is over an Enum and handles all of its 717 // values. We only issue a warning if there is not 'default:', but 718 // we still do the analysis to preserve this information in the AST 719 // (which can be used by flow-based analyes). 720 // 721 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 722 723 // If switch has default case, then ignore it. 724 if (!CaseListIsErroneous && !HasConstantCond && ET) { 725 const EnumDecl *ED = ET->getDecl(); 726 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 727 EnumValsTy EnumVals; 728 729 // Gather all enum values, set their type and sort them, 730 // allowing easier comparison with CaseVals. 731 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 732 EDI != ED->enumerator_end(); ++EDI) { 733 llvm::APSInt Val = EDI->getInitVal(); 734 AdjustAPSInt(Val, CondWidth, CondIsSigned); 735 EnumVals.push_back(std::make_pair(Val, *EDI)); 736 } 737 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 738 EnumValsTy::iterator EIend = 739 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 740 741 // See which case values aren't in enum. 742 // TODO: we might want to check whether case values are out of the 743 // enum even if we don't want to check whether all cases are handled. 744 if (!TheDefaultStmt) { 745 EnumValsTy::const_iterator EI = EnumVals.begin(); 746 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 747 CI != CaseVals.end(); CI++) { 748 while (EI != EIend && EI->first < CI->first) 749 EI++; 750 if (EI == EIend || EI->first > CI->first) 751 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 752 << ED->getDeclName(); 753 } 754 // See which of case ranges aren't in enum 755 EI = EnumVals.begin(); 756 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 757 RI != CaseRanges.end() && EI != EIend; RI++) { 758 while (EI != EIend && EI->first < RI->first) 759 EI++; 760 761 if (EI == EIend || EI->first != RI->first) { 762 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 763 << ED->getDeclName(); 764 } 765 766 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 767 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 768 while (EI != EIend && EI->first < Hi) 769 EI++; 770 if (EI == EIend || EI->first != Hi) 771 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 772 << ED->getDeclName(); 773 } 774 } 775 776 // Check which enum vals aren't in switch 777 CaseValsTy::const_iterator CI = CaseVals.begin(); 778 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 779 bool hasCasesNotInSwitch = false; 780 781 llvm::SmallVector<DeclarationName,8> UnhandledNames; 782 783 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 784 // Drop unneeded case values 785 llvm::APSInt CIVal; 786 while (CI != CaseVals.end() && CI->first < EI->first) 787 CI++; 788 789 if (CI != CaseVals.end() && CI->first == EI->first) 790 continue; 791 792 // Drop unneeded case ranges 793 for (; RI != CaseRanges.end(); RI++) { 794 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 795 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 796 if (EI->first <= Hi) 797 break; 798 } 799 800 if (RI == CaseRanges.end() || EI->first < RI->first) { 801 hasCasesNotInSwitch = true; 802 if (!TheDefaultStmt) 803 UnhandledNames.push_back(EI->second->getDeclName()); 804 } 805 } 806 807 // Produce a nice diagnostic if multiple values aren't handled. 808 switch (UnhandledNames.size()) { 809 case 0: break; 810 case 1: 811 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 812 << UnhandledNames[0]; 813 break; 814 case 2: 815 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 816 << UnhandledNames[0] << UnhandledNames[1]; 817 break; 818 case 3: 819 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 820 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 821 break; 822 default: 823 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 824 << (unsigned)UnhandledNames.size() 825 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 826 break; 827 } 828 829 if (!hasCasesNotInSwitch) 830 SS->setAllEnumCasesCovered(); 831 } 832 } 833 834 // FIXME: If the case list was broken is some way, we don't have a good system 835 // to patch it up. Instead, just return the whole substmt as broken. 836 if (CaseListIsErroneous) 837 return StmtError(); 838 839 return Owned(SS); 840} 841 842StmtResult 843Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 844 Decl *CondVar, Stmt *Body) { 845 ExprResult CondResult(Cond.release()); 846 847 VarDecl *ConditionVar = 0; 848 if (CondVar) { 849 ConditionVar = cast<VarDecl>(CondVar); 850 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 851 if (CondResult.isInvalid()) 852 return StmtError(); 853 } 854 Expr *ConditionExpr = CondResult.take(); 855 if (!ConditionExpr) 856 return StmtError(); 857 858 DiagnoseUnusedExprResult(Body); 859 860 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 861 Body, WhileLoc)); 862} 863 864StmtResult 865Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 866 SourceLocation WhileLoc, SourceLocation CondLParen, 867 Expr *Cond, SourceLocation CondRParen) { 868 assert(Cond && "ActOnDoStmt(): missing expression"); 869 870 if (CheckBooleanCondition(Cond, DoLoc)) 871 return StmtError(); 872 873 CheckImplicitConversions(Cond, DoLoc); 874 ExprResult CondResult = MaybeCreateExprWithCleanups(Cond); 875 if (CondResult.isInvalid()) 876 return StmtError(); 877 Cond = CondResult.take(); 878 879 DiagnoseUnusedExprResult(Body); 880 881 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 882} 883 884StmtResult 885Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 886 Stmt *First, FullExprArg second, Decl *secondVar, 887 FullExprArg third, 888 SourceLocation RParenLoc, Stmt *Body) { 889 if (!getLangOptions().CPlusPlus) { 890 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 891 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 892 // declare identifiers for objects having storage class 'auto' or 893 // 'register'. 894 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 895 DI!=DE; ++DI) { 896 VarDecl *VD = dyn_cast<VarDecl>(*DI); 897 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 898 VD = 0; 899 if (VD == 0) 900 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 901 // FIXME: mark decl erroneous! 902 } 903 } 904 } 905 906 ExprResult SecondResult(second.release()); 907 VarDecl *ConditionVar = 0; 908 if (secondVar) { 909 ConditionVar = cast<VarDecl>(secondVar); 910 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 911 if (SecondResult.isInvalid()) 912 return StmtError(); 913 } 914 915 Expr *Third = third.release().takeAs<Expr>(); 916 917 DiagnoseUnusedExprResult(First); 918 DiagnoseUnusedExprResult(Third); 919 DiagnoseUnusedExprResult(Body); 920 921 return Owned(new (Context) ForStmt(Context, First, 922 SecondResult.take(), ConditionVar, 923 Third, Body, ForLoc, LParenLoc, 924 RParenLoc)); 925} 926 927/// In an Objective C collection iteration statement: 928/// for (x in y) 929/// x can be an arbitrary l-value expression. Bind it up as a 930/// full-expression. 931StmtResult Sema::ActOnForEachLValueExpr(Expr *E) { 932 CheckImplicitConversions(E); 933 ExprResult Result = MaybeCreateExprWithCleanups(E); 934 if (Result.isInvalid()) return StmtError(); 935 return Owned(static_cast<Stmt*>(Result.get())); 936} 937 938StmtResult 939Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 940 SourceLocation LParenLoc, 941 Stmt *First, Expr *Second, 942 SourceLocation RParenLoc, Stmt *Body) { 943 if (First) { 944 QualType FirstType; 945 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 946 if (!DS->isSingleDecl()) 947 return StmtError(Diag((*DS->decl_begin())->getLocation(), 948 diag::err_toomany_element_decls)); 949 950 Decl *D = DS->getSingleDecl(); 951 FirstType = cast<ValueDecl>(D)->getType(); 952 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 953 // declare identifiers for objects having storage class 'auto' or 954 // 'register'. 955 VarDecl *VD = cast<VarDecl>(D); 956 if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) 957 return StmtError(Diag(VD->getLocation(), 958 diag::err_non_variable_decl_in_for)); 959 } else { 960 Expr *FirstE = cast<Expr>(First); 961 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 962 return StmtError(Diag(First->getLocStart(), 963 diag::err_selector_element_not_lvalue) 964 << First->getSourceRange()); 965 966 FirstType = static_cast<Expr*>(First)->getType(); 967 } 968 if (!FirstType->isDependentType() && 969 !FirstType->isObjCObjectPointerType() && 970 !FirstType->isBlockPointerType()) 971 Diag(ForLoc, diag::err_selector_element_type) 972 << FirstType << First->getSourceRange(); 973 } 974 if (Second && !Second->isTypeDependent()) { 975 DefaultFunctionArrayLvalueConversion(Second); 976 QualType SecondType = Second->getType(); 977 if (!SecondType->isObjCObjectPointerType()) 978 Diag(ForLoc, diag::err_collection_expr_type) 979 << SecondType << Second->getSourceRange(); 980 else if (const ObjCObjectPointerType *OPT = 981 SecondType->getAsObjCInterfacePointerType()) { 982 llvm::SmallVector<IdentifierInfo *, 4> KeyIdents; 983 IdentifierInfo* selIdent = 984 &Context.Idents.get("countByEnumeratingWithState"); 985 KeyIdents.push_back(selIdent); 986 selIdent = &Context.Idents.get("objects"); 987 KeyIdents.push_back(selIdent); 988 selIdent = &Context.Idents.get("count"); 989 KeyIdents.push_back(selIdent); 990 Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]); 991 if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) { 992 if (!IDecl->isForwardDecl() && 993 !IDecl->lookupInstanceMethod(CSelector)) { 994 // Must further look into private implementation methods. 995 if (!LookupPrivateInstanceMethod(CSelector, IDecl)) 996 Diag(ForLoc, diag::warn_collection_expr_type) 997 << SecondType << CSelector << Second->getSourceRange(); 998 } 999 } 1000 } 1001 } 1002 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1003 ForLoc, RParenLoc)); 1004} 1005 1006StmtResult Sema::ActOnGotoStmt(SourceLocation GotoLoc, 1007 SourceLocation LabelLoc, 1008 LabelDecl *TheDecl) { 1009 getCurFunction()->setHasBranchIntoScope(); 1010 TheDecl->setUsed(); 1011 return Owned(new (Context) GotoStmt(TheDecl, GotoLoc, LabelLoc)); 1012} 1013 1014StmtResult 1015Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1016 Expr *E) { 1017 // Convert operand to void* 1018 if (!E->isTypeDependent()) { 1019 QualType ETy = E->getType(); 1020 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1021 AssignConvertType ConvTy = 1022 CheckSingleAssignmentConstraints(DestTy, E); 1023 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1024 return StmtError(); 1025 } 1026 1027 getCurFunction()->setHasIndirectGoto(); 1028 1029 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1030} 1031 1032StmtResult 1033Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1034 Scope *S = CurScope->getContinueParent(); 1035 if (!S) { 1036 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1037 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1038 } 1039 1040 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1041} 1042 1043StmtResult 1044Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1045 Scope *S = CurScope->getBreakParent(); 1046 if (!S) { 1047 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1048 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1049 } 1050 1051 return Owned(new (Context) BreakStmt(BreakLoc)); 1052} 1053 1054/// \brief Determine whether the given expression is a candidate for 1055/// copy elision in either a return statement or a throw expression. 1056/// 1057/// \param ReturnType If we're determining the copy elision candidate for 1058/// a return statement, this is the return type of the function. If we're 1059/// determining the copy elision candidate for a throw expression, this will 1060/// be a NULL type. 1061/// 1062/// \param E The expression being returned from the function or block, or 1063/// being thrown. 1064/// 1065/// \param AllowFunctionParameter 1066/// 1067/// \returns The NRVO candidate variable, if the return statement may use the 1068/// NRVO, or NULL if there is no such candidate. 1069const VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, 1070 Expr *E, 1071 bool AllowFunctionParameter) { 1072 QualType ExprType = E->getType(); 1073 // - in a return statement in a function with ... 1074 // ... a class return type ... 1075 if (!ReturnType.isNull()) { 1076 if (!ReturnType->isRecordType()) 1077 return 0; 1078 // ... the same cv-unqualified type as the function return type ... 1079 if (!Context.hasSameUnqualifiedType(ReturnType, ExprType)) 1080 return 0; 1081 } 1082 1083 // ... the expression is the name of a non-volatile automatic object 1084 // (other than a function or catch-clause parameter)) ... 1085 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E->IgnoreParens()); 1086 if (!DR) 1087 return 0; 1088 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1089 if (!VD) 1090 return 0; 1091 1092 if (VD->hasLocalStorage() && !VD->isExceptionVariable() && 1093 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1094 !VD->getType().isVolatileQualified() && 1095 ((VD->getKind() == Decl::Var) || 1096 (AllowFunctionParameter && VD->getKind() == Decl::ParmVar))) 1097 return VD; 1098 1099 return 0; 1100} 1101 1102/// \brief Perform the initialization of a potentially-movable value, which 1103/// is the result of return value. 1104/// 1105/// This routine implements C++0x [class.copy]p33, which attempts to treat 1106/// returned lvalues as rvalues in certain cases (to prefer move construction), 1107/// then falls back to treating them as lvalues if that failed. 1108ExprResult 1109Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity, 1110 const VarDecl *NRVOCandidate, 1111 QualType ResultType, 1112 Expr *Value) { 1113 // C++0x [class.copy]p33: 1114 // When the criteria for elision of a copy operation are met or would 1115 // be met save for the fact that the source object is a function 1116 // parameter, and the object to be copied is designated by an lvalue, 1117 // overload resolution to select the constructor for the copy is first 1118 // performed as if the object were designated by an rvalue. 1119 ExprResult Res = ExprError(); 1120 if (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true)) { 1121 ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, 1122 Value->getType(), CK_LValueToRValue, 1123 Value, VK_XValue); 1124 1125 Expr *InitExpr = &AsRvalue; 1126 InitializationKind Kind 1127 = InitializationKind::CreateCopy(Value->getLocStart(), 1128 Value->getLocStart()); 1129 InitializationSequence Seq(*this, Entity, Kind, &InitExpr, 1); 1130 1131 // [...] If overload resolution fails, or if the type of the first 1132 // parameter of the selected constructor is not an rvalue reference 1133 // to the object's type (possibly cv-qualified), overload resolution 1134 // is performed again, considering the object as an lvalue. 1135 if (Seq.getKind() != InitializationSequence::FailedSequence) { 1136 for (InitializationSequence::step_iterator Step = Seq.step_begin(), 1137 StepEnd = Seq.step_end(); 1138 Step != StepEnd; ++Step) { 1139 if (Step->Kind 1140 != InitializationSequence::SK_ConstructorInitialization) 1141 continue; 1142 1143 CXXConstructorDecl *Constructor 1144 = cast<CXXConstructorDecl>(Step->Function.Function); 1145 1146 const RValueReferenceType *RRefType 1147 = Constructor->getParamDecl(0)->getType() 1148 ->getAs<RValueReferenceType>(); 1149 1150 // If we don't meet the criteria, break out now. 1151 if (!RRefType || 1152 !Context.hasSameUnqualifiedType(RRefType->getPointeeType(), 1153 Context.getTypeDeclType(Constructor->getParent()))) 1154 break; 1155 1156 // Promote "AsRvalue" to the heap, since we now need this 1157 // expression node to persist. 1158 Value = ImplicitCastExpr::Create(Context, Value->getType(), 1159 CK_LValueToRValue, Value, 0, 1160 VK_XValue); 1161 1162 // Complete type-checking the initialization of the return type 1163 // using the constructor we found. 1164 Res = Seq.Perform(*this, Entity, Kind, MultiExprArg(&Value, 1)); 1165 } 1166 } 1167 } 1168 1169 // Either we didn't meet the criteria for treating an lvalue as an rvalue, 1170 // above, or overload resolution failed. Either way, we need to try 1171 // (again) now with the return value expression as written. 1172 if (Res.isInvalid()) 1173 Res = PerformCopyInitialization(Entity, SourceLocation(), Value); 1174 1175 return Res; 1176} 1177 1178/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1179/// 1180StmtResult 1181Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1182 // If this is the first return we've seen in the block, infer the type of 1183 // the block from it. 1184 BlockScopeInfo *CurBlock = getCurBlock(); 1185 if (CurBlock->ReturnType.isNull()) { 1186 if (RetValExp) { 1187 // Don't call UsualUnaryConversions(), since we don't want to do 1188 // integer promotions here. 1189 DefaultFunctionArrayLvalueConversion(RetValExp); 1190 CurBlock->ReturnType = RetValExp->getType(); 1191 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1192 // We have to remove a 'const' added to copied-in variable which was 1193 // part of the implementation spec. and not the actual qualifier for 1194 // the variable. 1195 if (CDRE->isConstQualAdded()) 1196 CurBlock->ReturnType.removeLocalConst(); // FIXME: local??? 1197 } 1198 } else 1199 CurBlock->ReturnType = Context.VoidTy; 1200 } 1201 QualType FnRetType = CurBlock->ReturnType; 1202 1203 if (CurBlock->FunctionType->getAs<FunctionType>()->getNoReturnAttr()) { 1204 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1205 << getCurFunctionOrMethodDecl()->getDeclName(); 1206 return StmtError(); 1207 } 1208 1209 // Otherwise, verify that this result type matches the previous one. We are 1210 // pickier with blocks than for normal functions because we don't have GCC 1211 // compatibility to worry about here. 1212 ReturnStmt *Result = 0; 1213 if (CurBlock->ReturnType->isVoidType()) { 1214 if (RetValExp) { 1215 Diag(ReturnLoc, diag::err_return_block_has_expr); 1216 RetValExp = 0; 1217 } 1218 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1219 } else if (!RetValExp) { 1220 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1221 } else { 1222 const VarDecl *NRVOCandidate = 0; 1223 1224 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1225 // we have a non-void block with an expression, continue checking 1226 1227 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1228 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1229 // function return. 1230 1231 // In C++ the return statement is handled via a copy initialization. 1232 // the C version of which boils down to CheckSingleAssignmentConstraints. 1233 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1234 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1235 FnRetType, 1236 NRVOCandidate != 0); 1237 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1238 FnRetType, RetValExp); 1239 if (Res.isInvalid()) { 1240 // FIXME: Cleanup temporaries here, anyway? 1241 return StmtError(); 1242 } 1243 1244 if (RetValExp) { 1245 CheckImplicitConversions(RetValExp, ReturnLoc); 1246 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1247 } 1248 1249 RetValExp = Res.takeAs<Expr>(); 1250 if (RetValExp) 1251 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1252 } 1253 1254 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1255 } 1256 1257 // If we need to check for the named return value optimization, save the 1258 // return statement in our scope for later processing. 1259 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1260 !CurContext->isDependentContext()) 1261 FunctionScopes.back()->Returns.push_back(Result); 1262 1263 return Owned(Result); 1264} 1265 1266StmtResult 1267Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1268 if (getCurBlock()) 1269 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1270 1271 QualType FnRetType; 1272 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1273 FnRetType = FD->getResultType(); 1274 if (FD->hasAttr<NoReturnAttr>() || 1275 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1276 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1277 << getCurFunctionOrMethodDecl()->getDeclName(); 1278 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1279 FnRetType = MD->getResultType(); 1280 else // If we don't have a function/method context, bail. 1281 return StmtError(); 1282 1283 ReturnStmt *Result = 0; 1284 if (FnRetType->isVoidType()) { 1285 if (RetValExp && !RetValExp->isTypeDependent()) { 1286 // C99 6.8.6.4p1 (ext_ since GCC warns) 1287 unsigned D = diag::ext_return_has_expr; 1288 if (RetValExp->getType()->isVoidType()) 1289 D = diag::ext_return_has_void_expr; 1290 else { 1291 IgnoredValueConversions(RetValExp); 1292 ImpCastExprToType(RetValExp, Context.VoidTy, CK_ToVoid); 1293 } 1294 1295 // return (some void expression); is legal in C++. 1296 if (D != diag::ext_return_has_void_expr || 1297 !getLangOptions().CPlusPlus) { 1298 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1299 Diag(ReturnLoc, D) 1300 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1301 << RetValExp->getSourceRange(); 1302 } 1303 1304 CheckImplicitConversions(RetValExp, ReturnLoc); 1305 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1306 } 1307 1308 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1309 } else if (!RetValExp && !FnRetType->isDependentType()) { 1310 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1311 // C99 6.8.6.4p1 (ext_ since GCC warns) 1312 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1313 1314 if (FunctionDecl *FD = getCurFunctionDecl()) 1315 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1316 else 1317 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1318 Result = new (Context) ReturnStmt(ReturnLoc); 1319 } else { 1320 const VarDecl *NRVOCandidate = 0; 1321 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1322 // we have a non-void function with an expression, continue checking 1323 1324 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1325 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1326 // function return. 1327 1328 // In C++ the return statement is handled via a copy initialization. 1329 // the C version of which boils down to CheckSingleAssignmentConstraints. 1330 NRVOCandidate = getCopyElisionCandidate(FnRetType, RetValExp, false); 1331 InitializedEntity Entity = InitializedEntity::InitializeResult(ReturnLoc, 1332 FnRetType, 1333 NRVOCandidate != 0); 1334 ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRVOCandidate, 1335 FnRetType, RetValExp); 1336 if (Res.isInvalid()) { 1337 // FIXME: Cleanup temporaries here, anyway? 1338 return StmtError(); 1339 } 1340 1341 RetValExp = Res.takeAs<Expr>(); 1342 if (RetValExp) 1343 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1344 } 1345 1346 if (RetValExp) { 1347 CheckImplicitConversions(RetValExp, ReturnLoc); 1348 RetValExp = MaybeCreateExprWithCleanups(RetValExp); 1349 } 1350 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1351 } 1352 1353 // If we need to check for the named return value optimization, save the 1354 // return statement in our scope for later processing. 1355 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1356 !CurContext->isDependentContext()) 1357 FunctionScopes.back()->Returns.push_back(Result); 1358 1359 return Owned(Result); 1360} 1361 1362/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1363/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1364/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1365/// provide a strong guidance to not use it. 1366/// 1367/// This method checks to see if the argument is an acceptable l-value and 1368/// returns false if it is a case we can handle. 1369static bool CheckAsmLValue(const Expr *E, Sema &S) { 1370 // Type dependent expressions will be checked during instantiation. 1371 if (E->isTypeDependent()) 1372 return false; 1373 1374 if (E->isLValue()) 1375 return false; // Cool, this is an lvalue. 1376 1377 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1378 // are supposed to allow. 1379 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1380 if (E != E2 && E2->isLValue()) { 1381 if (!S.getLangOptions().HeinousExtensions) 1382 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1383 << E->getSourceRange(); 1384 else 1385 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1386 << E->getSourceRange(); 1387 // Accept, even if we emitted an error diagnostic. 1388 return false; 1389 } 1390 1391 // None of the above, just randomly invalid non-lvalue. 1392 return true; 1393} 1394 1395 1396StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1397 bool IsSimple, 1398 bool IsVolatile, 1399 unsigned NumOutputs, 1400 unsigned NumInputs, 1401 IdentifierInfo **Names, 1402 MultiExprArg constraints, 1403 MultiExprArg exprs, 1404 Expr *asmString, 1405 MultiExprArg clobbers, 1406 SourceLocation RParenLoc, 1407 bool MSAsm) { 1408 unsigned NumClobbers = clobbers.size(); 1409 StringLiteral **Constraints = 1410 reinterpret_cast<StringLiteral**>(constraints.get()); 1411 Expr **Exprs = exprs.get(); 1412 StringLiteral *AsmString = cast<StringLiteral>(asmString); 1413 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1414 1415 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1416 1417 // The parser verifies that there is a string literal here. 1418 if (AsmString->isWide()) 1419 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1420 << AsmString->getSourceRange()); 1421 1422 for (unsigned i = 0; i != NumOutputs; i++) { 1423 StringLiteral *Literal = Constraints[i]; 1424 if (Literal->isWide()) 1425 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1426 << Literal->getSourceRange()); 1427 1428 llvm::StringRef OutputName; 1429 if (Names[i]) 1430 OutputName = Names[i]->getName(); 1431 1432 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1433 if (!Context.Target.validateOutputConstraint(Info)) 1434 return StmtError(Diag(Literal->getLocStart(), 1435 diag::err_asm_invalid_output_constraint) 1436 << Info.getConstraintStr()); 1437 1438 // Check that the output exprs are valid lvalues. 1439 Expr *OutputExpr = Exprs[i]; 1440 if (CheckAsmLValue(OutputExpr, *this)) { 1441 return StmtError(Diag(OutputExpr->getLocStart(), 1442 diag::err_asm_invalid_lvalue_in_output) 1443 << OutputExpr->getSourceRange()); 1444 } 1445 1446 OutputConstraintInfos.push_back(Info); 1447 } 1448 1449 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1450 1451 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1452 StringLiteral *Literal = Constraints[i]; 1453 if (Literal->isWide()) 1454 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1455 << Literal->getSourceRange()); 1456 1457 llvm::StringRef InputName; 1458 if (Names[i]) 1459 InputName = Names[i]->getName(); 1460 1461 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1462 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1463 NumOutputs, Info)) { 1464 return StmtError(Diag(Literal->getLocStart(), 1465 diag::err_asm_invalid_input_constraint) 1466 << Info.getConstraintStr()); 1467 } 1468 1469 Expr *InputExpr = Exprs[i]; 1470 1471 // Only allow void types for memory constraints. 1472 if (Info.allowsMemory() && !Info.allowsRegister()) { 1473 if (CheckAsmLValue(InputExpr, *this)) 1474 return StmtError(Diag(InputExpr->getLocStart(), 1475 diag::err_asm_invalid_lvalue_in_input) 1476 << Info.getConstraintStr() 1477 << InputExpr->getSourceRange()); 1478 } 1479 1480 if (Info.allowsRegister()) { 1481 if (InputExpr->getType()->isVoidType()) { 1482 return StmtError(Diag(InputExpr->getLocStart(), 1483 diag::err_asm_invalid_type_in_input) 1484 << InputExpr->getType() << Info.getConstraintStr() 1485 << InputExpr->getSourceRange()); 1486 } 1487 } 1488 1489 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1490 1491 InputConstraintInfos.push_back(Info); 1492 } 1493 1494 // Check that the clobbers are valid. 1495 for (unsigned i = 0; i != NumClobbers; i++) { 1496 StringLiteral *Literal = Clobbers[i]; 1497 if (Literal->isWide()) 1498 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1499 << Literal->getSourceRange()); 1500 1501 llvm::StringRef Clobber = Literal->getString(); 1502 1503 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1504 return StmtError(Diag(Literal->getLocStart(), 1505 diag::err_asm_unknown_register_name) << Clobber); 1506 } 1507 1508 AsmStmt *NS = 1509 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1510 NumOutputs, NumInputs, Names, Constraints, Exprs, 1511 AsmString, NumClobbers, Clobbers, RParenLoc); 1512 // Validate the asm string, ensuring it makes sense given the operands we 1513 // have. 1514 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1515 unsigned DiagOffs; 1516 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1517 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1518 << AsmString->getSourceRange(); 1519 return StmtError(); 1520 } 1521 1522 // Validate tied input operands for type mismatches. 1523 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1524 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1525 1526 // If this is a tied constraint, verify that the output and input have 1527 // either exactly the same type, or that they are int/ptr operands with the 1528 // same size (int/long, int*/long, are ok etc). 1529 if (!Info.hasTiedOperand()) continue; 1530 1531 unsigned TiedTo = Info.getTiedOperand(); 1532 Expr *OutputExpr = Exprs[TiedTo]; 1533 Expr *InputExpr = Exprs[i+NumOutputs]; 1534 QualType InTy = InputExpr->getType(); 1535 QualType OutTy = OutputExpr->getType(); 1536 if (Context.hasSameType(InTy, OutTy)) 1537 continue; // All types can be tied to themselves. 1538 1539 // Decide if the input and output are in the same domain (integer/ptr or 1540 // floating point. 1541 enum AsmDomain { 1542 AD_Int, AD_FP, AD_Other 1543 } InputDomain, OutputDomain; 1544 1545 if (InTy->isIntegerType() || InTy->isPointerType()) 1546 InputDomain = AD_Int; 1547 else if (InTy->isRealFloatingType()) 1548 InputDomain = AD_FP; 1549 else 1550 InputDomain = AD_Other; 1551 1552 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1553 OutputDomain = AD_Int; 1554 else if (OutTy->isRealFloatingType()) 1555 OutputDomain = AD_FP; 1556 else 1557 OutputDomain = AD_Other; 1558 1559 // They are ok if they are the same size and in the same domain. This 1560 // allows tying things like: 1561 // void* to int* 1562 // void* to int if they are the same size. 1563 // double to long double if they are the same size. 1564 // 1565 uint64_t OutSize = Context.getTypeSize(OutTy); 1566 uint64_t InSize = Context.getTypeSize(InTy); 1567 if (OutSize == InSize && InputDomain == OutputDomain && 1568 InputDomain != AD_Other) 1569 continue; 1570 1571 // If the smaller input/output operand is not mentioned in the asm string, 1572 // then we can promote it and the asm string won't notice. Check this 1573 // case now. 1574 bool SmallerValueMentioned = false; 1575 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1576 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1577 if (!Piece.isOperand()) continue; 1578 1579 // If this is a reference to the input and if the input was the smaller 1580 // one, then we have to reject this asm. 1581 if (Piece.getOperandNo() == i+NumOutputs) { 1582 if (InSize < OutSize) { 1583 SmallerValueMentioned = true; 1584 break; 1585 } 1586 } 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 (Piece.getOperandNo() == TiedTo) { 1591 if (InSize > OutSize) { 1592 SmallerValueMentioned = true; 1593 break; 1594 } 1595 } 1596 } 1597 1598 // If the smaller value wasn't mentioned in the asm string, and if the 1599 // output was a register, just extend the shorter one to the size of the 1600 // larger one. 1601 if (!SmallerValueMentioned && InputDomain != AD_Other && 1602 OutputConstraintInfos[TiedTo].allowsRegister()) 1603 continue; 1604 1605 Diag(InputExpr->getLocStart(), 1606 diag::err_asm_tying_incompatible_types) 1607 << InTy << OutTy << OutputExpr->getSourceRange() 1608 << InputExpr->getSourceRange(); 1609 return StmtError(); 1610 } 1611 1612 return Owned(NS); 1613} 1614 1615StmtResult 1616Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1617 SourceLocation RParen, Decl *Parm, 1618 Stmt *Body) { 1619 VarDecl *Var = cast_or_null<VarDecl>(Parm); 1620 if (Var && Var->isInvalidDecl()) 1621 return StmtError(); 1622 1623 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 1624} 1625 1626StmtResult 1627Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 1628 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 1629} 1630 1631StmtResult 1632Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 1633 MultiStmtArg CatchStmts, Stmt *Finally) { 1634 if (!getLangOptions().ObjCExceptions) 1635 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@try"; 1636 1637 getCurFunction()->setHasBranchProtectedScope(); 1638 unsigned NumCatchStmts = CatchStmts.size(); 1639 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 1640 CatchStmts.release(), 1641 NumCatchStmts, 1642 Finally)); 1643} 1644 1645StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 1646 Expr *Throw) { 1647 if (Throw) { 1648 DefaultLvalueConversion(Throw); 1649 1650 QualType ThrowType = Throw->getType(); 1651 // Make sure the expression type is an ObjC pointer or "void *". 1652 if (!ThrowType->isDependentType() && 1653 !ThrowType->isObjCObjectPointerType()) { 1654 const PointerType *PT = ThrowType->getAs<PointerType>(); 1655 if (!PT || !PT->getPointeeType()->isVoidType()) 1656 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1657 << Throw->getType() << Throw->getSourceRange()); 1658 } 1659 } 1660 1661 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 1662} 1663 1664StmtResult 1665Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 1666 Scope *CurScope) { 1667 if (!getLangOptions().ObjCExceptions) 1668 Diag(AtLoc, diag::err_objc_exceptions_disabled) << "@throw"; 1669 1670 if (!Throw) { 1671 // @throw without an expression designates a rethrow (which much occur 1672 // in the context of an @catch clause). 1673 Scope *AtCatchParent = CurScope; 1674 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1675 AtCatchParent = AtCatchParent->getParent(); 1676 if (!AtCatchParent) 1677 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1678 } 1679 1680 return BuildObjCAtThrowStmt(AtLoc, Throw); 1681} 1682 1683StmtResult 1684Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 1685 Stmt *SyncBody) { 1686 getCurFunction()->setHasBranchProtectedScope(); 1687 1688 DefaultLvalueConversion(SyncExpr); 1689 1690 // Make sure the expression type is an ObjC pointer or "void *". 1691 if (!SyncExpr->getType()->isDependentType() && 1692 !SyncExpr->getType()->isObjCObjectPointerType()) { 1693 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1694 if (!PT || !PT->getPointeeType()->isVoidType()) 1695 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1696 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1697 } 1698 1699 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 1700} 1701 1702/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1703/// and creates a proper catch handler from them. 1704StmtResult 1705Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 1706 Stmt *HandlerBlock) { 1707 // There's nothing to test that ActOnExceptionDecl didn't already test. 1708 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1709 cast_or_null<VarDecl>(ExDecl), 1710 HandlerBlock)); 1711} 1712 1713namespace { 1714 1715class TypeWithHandler { 1716 QualType t; 1717 CXXCatchStmt *stmt; 1718public: 1719 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1720 : t(type), stmt(statement) {} 1721 1722 // An arbitrary order is fine as long as it places identical 1723 // types next to each other. 1724 bool operator<(const TypeWithHandler &y) const { 1725 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1726 return true; 1727 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1728 return false; 1729 else 1730 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1731 } 1732 1733 bool operator==(const TypeWithHandler& other) const { 1734 return t == other.t; 1735 } 1736 1737 CXXCatchStmt *getCatchStmt() const { return stmt; } 1738 SourceLocation getTypeSpecStartLoc() const { 1739 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1740 } 1741}; 1742 1743} 1744 1745/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1746/// handlers and creates a try statement from them. 1747StmtResult 1748Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 1749 MultiStmtArg RawHandlers) { 1750 if (!getLangOptions().Exceptions) 1751 Diag(TryLoc, diag::err_exceptions_disabled) << "try"; 1752 1753 unsigned NumHandlers = RawHandlers.size(); 1754 assert(NumHandlers > 0 && 1755 "The parser shouldn't call this if there are no handlers."); 1756 Stmt **Handlers = RawHandlers.get(); 1757 1758 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1759 1760 for (unsigned i = 0; i < NumHandlers; ++i) { 1761 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1762 if (!Handler->getExceptionDecl()) { 1763 if (i < NumHandlers - 1) 1764 return StmtError(Diag(Handler->getLocStart(), 1765 diag::err_early_catch_all)); 1766 1767 continue; 1768 } 1769 1770 const QualType CaughtType = Handler->getCaughtType(); 1771 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1772 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1773 } 1774 1775 // Detect handlers for the same type as an earlier one. 1776 if (NumHandlers > 1) { 1777 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1778 1779 TypeWithHandler prev = TypesWithHandlers[0]; 1780 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1781 TypeWithHandler curr = TypesWithHandlers[i]; 1782 1783 if (curr == prev) { 1784 Diag(curr.getTypeSpecStartLoc(), 1785 diag::warn_exception_caught_by_earlier_handler) 1786 << curr.getCatchStmt()->getCaughtType().getAsString(); 1787 Diag(prev.getTypeSpecStartLoc(), 1788 diag::note_previous_exception_handler) 1789 << prev.getCatchStmt()->getCaughtType().getAsString(); 1790 } 1791 1792 prev = curr; 1793 } 1794 } 1795 1796 getCurFunction()->setHasBranchProtectedScope(); 1797 1798 // FIXME: We should detect handlers that cannot catch anything because an 1799 // earlier handler catches a superclass. Need to find a method that is not 1800 // quadratic for this. 1801 // Neither of these are explicitly forbidden, but every compiler detects them 1802 // and warns. 1803 1804 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 1805 Handlers, NumHandlers)); 1806} 1807