SemaStmt.cpp revision 7eb0a9eb0cde8444b97f9c5b713d9be7a6f1e607
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 assert(E && "ActOnExprStmt(): missing expression"); 36 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 37 // void expression for its side effects. Conversion to void allows any 38 // operand, even incomplete types. 39 40 // Same thing in for stmt first clause (when expr) and third clause. 41 return Owned(static_cast<Stmt*>(E)); 42} 43 44 45StmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc, bool LeadingEmptyMacro) { 46 return Owned(new (Context) NullStmt(SemiLoc, LeadingEmptyMacro)); 47} 48 49StmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, 50 SourceLocation StartLoc, 51 SourceLocation EndLoc) { 52 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 53 54 // If we have an invalid decl, just return an error. 55 if (DG.isNull()) return StmtError(); 56 57 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 58} 59 60void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 61 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 62 63 // If we have an invalid decl, just return. 64 if (DG.isNull() || !DG.isSingleDecl()) return; 65 // suppress any potential 'unused variable' warning. 66 DG.getSingleDecl()->setUsed(); 67} 68 69void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 70 if (const LabelStmt *Label = dyn_cast_or_null<LabelStmt>(S)) 71 return DiagnoseUnusedExprResult(Label->getSubStmt()); 72 73 const Expr *E = dyn_cast_or_null<Expr>(S); 74 if (!E) 75 return; 76 77 if (E->isBoundMemberFunction(Context)) { 78 Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func) 79 << E->getSourceRange(); 80 return; 81 } 82 83 SourceLocation Loc; 84 SourceRange R1, R2; 85 if (!E->isUnusedResultAWarning(Loc, R1, R2, Context)) 86 return; 87 88 // Okay, we have an unused result. Depending on what the base expression is, 89 // we might want to make a more specific diagnostic. Check for one of these 90 // cases now. 91 unsigned DiagID = diag::warn_unused_expr; 92 E = E->IgnoreParens(); 93 if (isa<ObjCImplicitSetterGetterRefExpr>(E)) 94 DiagID = diag::warn_unused_property_expr; 95 96 if (const CXXExprWithTemporaries *Temps = dyn_cast<CXXExprWithTemporaries>(E)) 97 E = Temps->getSubExpr(); 98 99 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 100 if (E->getType()->isVoidType()) 101 return; 102 103 // If the callee has attribute pure, const, or warn_unused_result, warn with 104 // a more specific message to make it clear what is happening. 105 if (const Decl *FD = CE->getCalleeDecl()) { 106 if (FD->getAttr<WarnUnusedResultAttr>()) { 107 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 108 return; 109 } 110 if (FD->getAttr<PureAttr>()) { 111 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 112 return; 113 } 114 if (FD->getAttr<ConstAttr>()) { 115 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 116 return; 117 } 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 (const CXXFunctionalCastExpr *FC 127 = dyn_cast<CXXFunctionalCastExpr>(E)) { 128 if (isa<CXXConstructExpr>(FC->getSubExpr()) || 129 isa<CXXTemporaryObjectExpr>(FC->getSubExpr())) 130 return; 131 } 132 // Diagnose "(void*) blah" as a typo for "(void) blah". 133 else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) { 134 TypeSourceInfo *TI = CE->getTypeInfoAsWritten(); 135 QualType T = TI->getType(); 136 137 // We really do want to use the non-canonical type here. 138 if (T == Context.VoidPtrTy) { 139 PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc()); 140 141 Diag(Loc, diag::warn_unused_voidptr) 142 << FixItHint::CreateRemoval(TL.getStarLoc()); 143 return; 144 } 145 } 146 147 DiagRuntimeBehavior(Loc, PDiag(DiagID) << R1 << R2); 148} 149 150StmtResult 151Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 152 MultiStmtArg elts, bool isStmtExpr) { 153 unsigned NumElts = elts.size(); 154 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 155 // If we're in C89 mode, check that we don't have any decls after stmts. If 156 // so, emit an extension diagnostic. 157 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 158 // Note that __extension__ can be around a decl. 159 unsigned i = 0; 160 // Skip over all declarations. 161 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 162 /*empty*/; 163 164 // We found the end of the list or a statement. Scan for another declstmt. 165 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 166 /*empty*/; 167 168 if (i != NumElts) { 169 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 170 Diag(D->getLocation(), diag::ext_mixed_decls_code); 171 } 172 } 173 // Warn about unused expressions in statements. 174 for (unsigned i = 0; i != NumElts; ++i) { 175 // Ignore statements that are last in a statement expression. 176 if (isStmtExpr && i == NumElts - 1) 177 continue; 178 179 DiagnoseUnusedExprResult(Elts[i]); 180 } 181 182 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 183} 184 185StmtResult 186Sema::ActOnCaseStmt(SourceLocation CaseLoc, Expr *LHSVal, 187 SourceLocation DotDotDotLoc, Expr *RHSVal, 188 SourceLocation ColonLoc) { 189 assert((LHSVal != 0) && "missing expression in case statement"); 190 191 // C99 6.8.4.2p3: The expression shall be an integer constant. 192 // However, GCC allows any evaluatable integer expression. 193 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 194 VerifyIntegerConstantExpression(LHSVal)) 195 return StmtError(); 196 197 // GCC extension: The expression shall be an integer constant. 198 199 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 200 VerifyIntegerConstantExpression(RHSVal)) { 201 RHSVal = 0; // Recover by just forgetting about it. 202 } 203 204 if (getCurFunction()->SwitchStack.empty()) { 205 Diag(CaseLoc, diag::err_case_not_in_switch); 206 return StmtError(); 207 } 208 209 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 210 ColonLoc); 211 getCurFunction()->SwitchStack.back()->addSwitchCase(CS); 212 return Owned(CS); 213} 214 215/// ActOnCaseStmtBody - This installs a statement as the body of a case. 216void Sema::ActOnCaseStmtBody(Stmt *caseStmt, Stmt *SubStmt) { 217 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 218 CS->setSubStmt(SubStmt); 219} 220 221StmtResult 222Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 223 Stmt *SubStmt, Scope *CurScope) { 224 if (getCurFunction()->SwitchStack.empty()) { 225 Diag(DefaultLoc, diag::err_default_not_in_switch); 226 return Owned(SubStmt); 227 } 228 229 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 230 getCurFunction()->SwitchStack.back()->addSwitchCase(DS); 231 return Owned(DS); 232} 233 234StmtResult 235Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 236 SourceLocation ColonLoc, Stmt *SubStmt, 237 const AttributeList *Attr) { 238 // According to GCC docs, "the only attribute that makes sense after a label 239 // is 'unused'". 240 bool HasUnusedAttr = false; 241 for ( ; Attr; Attr = Attr->getNext()) { 242 if (Attr->getKind() == AttributeList::AT_unused) { 243 HasUnusedAttr = true; 244 } else { 245 Diag(Attr->getLoc(), diag::warn_label_attribute_not_unused); 246 Attr->setInvalid(true); 247 } 248 } 249 250 return ActOnLabelStmt(IdentLoc, II, ColonLoc, SubStmt, HasUnusedAttr); 251} 252 253StmtResult 254Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 255 SourceLocation ColonLoc, Stmt *SubStmt, 256 bool HasUnusedAttr) { 257 // Look up the record for this label identifier. 258 LabelStmt *&LabelDecl = getCurFunction()->LabelMap[II]; 259 260 // If not forward referenced or defined already, just create a new LabelStmt. 261 if (LabelDecl == 0) 262 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt, 263 HasUnusedAttr)); 264 265 assert(LabelDecl->getID() == II && "Label mismatch!"); 266 267 // Otherwise, this label was either forward reference or multiply defined. If 268 // multiply defined, reject it now. 269 if (LabelDecl->getSubStmt()) { 270 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 271 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 272 return Owned(SubStmt); 273 } 274 275 // Otherwise, this label was forward declared, and we just found its real 276 // definition. Fill in the forward definition and return it. 277 LabelDecl->setIdentLoc(IdentLoc); 278 LabelDecl->setSubStmt(SubStmt); 279 LabelDecl->setUnusedAttribute(HasUnusedAttr); 280 return Owned(LabelDecl); 281} 282 283StmtResult 284Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar, 285 Stmt *thenStmt, SourceLocation ElseLoc, 286 Stmt *elseStmt) { 287 ExprResult CondResult(CondVal.release()); 288 289 VarDecl *ConditionVar = 0; 290 if (CondVar) { 291 ConditionVar = cast<VarDecl>(CondVar); 292 CondResult = CheckConditionVariable(ConditionVar, IfLoc, true); 293 if (CondResult.isInvalid()) 294 return StmtError(); 295 } 296 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 297 if (!ConditionExpr) 298 return StmtError(); 299 300 DiagnoseUnusedExprResult(thenStmt); 301 302 // Warn if the if block has a null body without an else value. 303 // this helps prevent bugs due to typos, such as 304 // if (condition); 305 // do_stuff(); 306 // 307 if (!elseStmt) { 308 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 309 // But do not warn if the body is a macro that expands to nothing, e.g: 310 // 311 // #define CALL(x) 312 // if (condition) 313 // CALL(0); 314 // 315 if (!stmt->hasLeadingEmptyMacro()) 316 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 317 } 318 319 DiagnoseUnusedExprResult(elseStmt); 320 321 return Owned(new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr, 322 thenStmt, ElseLoc, elseStmt)); 323} 324 325/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 326/// the specified width and sign. If an overflow occurs, detect it and emit 327/// the specified diagnostic. 328void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 329 unsigned NewWidth, bool NewSign, 330 SourceLocation Loc, 331 unsigned DiagID) { 332 // Perform a conversion to the promoted condition type if needed. 333 if (NewWidth > Val.getBitWidth()) { 334 // If this is an extension, just do it. 335 Val.extend(NewWidth); 336 Val.setIsSigned(NewSign); 337 338 // If the input was signed and negative and the output is 339 // unsigned, don't bother to warn: this is implementation-defined 340 // behavior. 341 // FIXME: Introduce a second, default-ignored warning for this case? 342 } else if (NewWidth < Val.getBitWidth()) { 343 // If this is a truncation, check for overflow. 344 llvm::APSInt ConvVal(Val); 345 ConvVal.trunc(NewWidth); 346 ConvVal.setIsSigned(NewSign); 347 ConvVal.extend(Val.getBitWidth()); 348 ConvVal.setIsSigned(Val.isSigned()); 349 if (ConvVal != Val) 350 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 351 352 // Regardless of whether a diagnostic was emitted, really do the 353 // truncation. 354 Val.trunc(NewWidth); 355 Val.setIsSigned(NewSign); 356 } else if (NewSign != Val.isSigned()) { 357 // Convert the sign to match the sign of the condition. This can cause 358 // overflow as well: unsigned(INTMIN) 359 // We don't diagnose this overflow, because it is implementation-defined 360 // behavior. 361 // FIXME: Introduce a second, default-ignored warning for this case? 362 llvm::APSInt OldVal(Val); 363 Val.setIsSigned(NewSign); 364 } 365} 366 367namespace { 368 struct CaseCompareFunctor { 369 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 370 const llvm::APSInt &RHS) { 371 return LHS.first < RHS; 372 } 373 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 374 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 375 return LHS.first < RHS.first; 376 } 377 bool operator()(const llvm::APSInt &LHS, 378 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 379 return LHS < RHS.first; 380 } 381 }; 382} 383 384/// CmpCaseVals - Comparison predicate for sorting case values. 385/// 386static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 387 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 388 if (lhs.first < rhs.first) 389 return true; 390 391 if (lhs.first == rhs.first && 392 lhs.second->getCaseLoc().getRawEncoding() 393 < rhs.second->getCaseLoc().getRawEncoding()) 394 return true; 395 return false; 396} 397 398/// CmpEnumVals - Comparison predicate for sorting enumeration values. 399/// 400static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 401 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 402{ 403 return lhs.first < rhs.first; 404} 405 406/// EqEnumVals - Comparison preficate for uniqing enumeration values. 407/// 408static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 409 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 410{ 411 return lhs.first == rhs.first; 412} 413 414/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 415/// potentially integral-promoted expression @p expr. 416static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 417 if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) { 418 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 419 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 420 if (TypeBeforePromotion->isIntegralOrEnumerationType()) { 421 return TypeBeforePromotion; 422 } 423 } 424 return expr->getType(); 425} 426 427StmtResult 428Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond, 429 Decl *CondVar) { 430 ExprResult CondResult; 431 432 VarDecl *ConditionVar = 0; 433 if (CondVar) { 434 ConditionVar = cast<VarDecl>(CondVar); 435 CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false); 436 if (CondResult.isInvalid()) 437 return StmtError(); 438 439 Cond = CondResult.release(); 440 } 441 442 if (!Cond) 443 return StmtError(); 444 445 CondResult 446 = ConvertToIntegralOrEnumerationType(SwitchLoc, Cond, 447 PDiag(diag::err_typecheck_statement_requires_integer), 448 PDiag(diag::err_switch_incomplete_class_type) 449 << Cond->getSourceRange(), 450 PDiag(diag::err_switch_explicit_conversion), 451 PDiag(diag::note_switch_conversion), 452 PDiag(diag::err_switch_multiple_conversions), 453 PDiag(diag::note_switch_conversion), 454 PDiag(0)); 455 if (CondResult.isInvalid()) return StmtError(); 456 Cond = CondResult.take(); 457 458 if (!CondVar) { 459 CheckImplicitConversions(Cond, SwitchLoc); 460 CondResult = MaybeCreateCXXExprWithTemporaries(Cond); 461 if (CondResult.isInvalid()) 462 return StmtError(); 463 Cond = CondResult.take(); 464 } 465 466 getCurFunction()->setHasBranchIntoScope(); 467 468 SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond); 469 getCurFunction()->SwitchStack.push_back(SS); 470 return Owned(SS); 471} 472 473static void AdjustAPSInt(llvm::APSInt &Val, unsigned BitWidth, bool IsSigned) { 474 if (Val.getBitWidth() < BitWidth) 475 Val.extend(BitWidth); 476 else if (Val.getBitWidth() > BitWidth) 477 Val.trunc(BitWidth); 478 Val.setIsSigned(IsSigned); 479} 480 481StmtResult 482Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch, 483 Stmt *BodyStmt) { 484 SwitchStmt *SS = cast<SwitchStmt>(Switch); 485 assert(SS == getCurFunction()->SwitchStack.back() && 486 "switch stack missing push/pop!"); 487 488 SS->setBody(BodyStmt, SwitchLoc); 489 getCurFunction()->SwitchStack.pop_back(); 490 491 if (SS->getCond() == 0) 492 return StmtError(); 493 494 Expr *CondExpr = SS->getCond(); 495 Expr *CondExprBeforePromotion = CondExpr; 496 QualType CondTypeBeforePromotion = 497 GetTypeBeforeIntegralPromotion(CondExpr); 498 499 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 500 UsualUnaryConversions(CondExpr); 501 QualType CondType = CondExpr->getType(); 502 SS->setCond(CondExpr); 503 504 // C++ 6.4.2.p2: 505 // Integral promotions are performed (on the switch condition). 506 // 507 // A case value unrepresentable by the original switch condition 508 // type (before the promotion) doesn't make sense, even when it can 509 // be represented by the promoted type. Therefore we need to find 510 // the pre-promotion type of the switch condition. 511 if (!CondExpr->isTypeDependent()) { 512 // We have already converted the expression to an integral or enumeration 513 // type, when we started the switch statement. If we don't have an 514 // appropriate type now, just return an error. 515 if (!CondType->isIntegralOrEnumerationType()) 516 return StmtError(); 517 518 if (CondExpr->isKnownToHaveBooleanValue()) { 519 // switch(bool_expr) {...} is often a programmer error, e.g. 520 // switch(n && mask) { ... } // Doh - should be "n & mask". 521 // One can always use an if statement instead of switch(bool_expr). 522 Diag(SwitchLoc, diag::warn_bool_switch_condition) 523 << CondExpr->getSourceRange(); 524 } 525 } 526 527 // Get the bitwidth of the switched-on value before promotions. We must 528 // convert the integer case values to this width before comparison. 529 bool HasDependentValue 530 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 531 unsigned CondWidth 532 = HasDependentValue? 0 533 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 534 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 535 536 // Accumulate all of the case values in a vector so that we can sort them 537 // and detect duplicates. This vector contains the APInt for the case after 538 // it has been converted to the condition type. 539 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 540 CaseValsTy CaseVals; 541 542 // Keep track of any GNU case ranges we see. The APSInt is the low value. 543 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 544 CaseRangesTy CaseRanges; 545 546 DefaultStmt *TheDefaultStmt = 0; 547 548 bool CaseListIsErroneous = false; 549 550 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 551 SC = SC->getNextSwitchCase()) { 552 553 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 554 if (TheDefaultStmt) { 555 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 556 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 557 558 // FIXME: Remove the default statement from the switch block so that 559 // we'll return a valid AST. This requires recursing down the AST and 560 // finding it, not something we are set up to do right now. For now, 561 // just lop the entire switch stmt out of the AST. 562 CaseListIsErroneous = true; 563 } 564 TheDefaultStmt = DS; 565 566 } else { 567 CaseStmt *CS = cast<CaseStmt>(SC); 568 569 // We already verified that the expression has a i-c-e value (C99 570 // 6.8.4.2p3) - get that value now. 571 Expr *Lo = CS->getLHS(); 572 573 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 574 HasDependentValue = true; 575 break; 576 } 577 578 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 579 580 // Convert the value to the same width/sign as the condition. 581 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 582 Lo->getLocStart(), 583 diag::warn_case_value_overflow); 584 585 // If the LHS is not the same type as the condition, insert an implicit 586 // cast. 587 ImpCastExprToType(Lo, CondType, CK_IntegralCast); 588 CS->setLHS(Lo); 589 590 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 591 if (CS->getRHS()) { 592 if (CS->getRHS()->isTypeDependent() || 593 CS->getRHS()->isValueDependent()) { 594 HasDependentValue = true; 595 break; 596 } 597 CaseRanges.push_back(std::make_pair(LoVal, CS)); 598 } else 599 CaseVals.push_back(std::make_pair(LoVal, CS)); 600 } 601 } 602 603 if (!HasDependentValue) { 604 // If we don't have a default statement, check whether the 605 // condition is constant. 606 llvm::APSInt ConstantCondValue; 607 bool HasConstantCond = false; 608 bool ShouldCheckConstantCond = false; 609 if (!HasDependentValue && !TheDefaultStmt) { 610 Expr::EvalResult Result; 611 HasConstantCond = CondExprBeforePromotion->Evaluate(Result, Context); 612 if (HasConstantCond) { 613 assert(Result.Val.isInt() && "switch condition evaluated to non-int"); 614 ConstantCondValue = Result.Val.getInt(); 615 ShouldCheckConstantCond = true; 616 617 assert(ConstantCondValue.getBitWidth() == CondWidth && 618 ConstantCondValue.isSigned() == CondIsSigned); 619 } 620 } 621 622 // Sort all the scalar case values so we can easily detect duplicates. 623 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 624 625 if (!CaseVals.empty()) { 626 for (unsigned i = 0, e = CaseVals.size(); i != e; ++i) { 627 if (ShouldCheckConstantCond && 628 CaseVals[i].first == ConstantCondValue) 629 ShouldCheckConstantCond = false; 630 631 if (i != 0 && CaseVals[i].first == CaseVals[i-1].first) { 632 // If we have a duplicate, report it. 633 Diag(CaseVals[i].second->getLHS()->getLocStart(), 634 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 635 Diag(CaseVals[i-1].second->getLHS()->getLocStart(), 636 diag::note_duplicate_case_prev); 637 // FIXME: We really want to remove the bogus case stmt from the 638 // substmt, but we have no way to do this right now. 639 CaseListIsErroneous = true; 640 } 641 } 642 } 643 644 // Detect duplicate case ranges, which usually don't exist at all in 645 // the first place. 646 if (!CaseRanges.empty()) { 647 // Sort all the case ranges by their low value so we can easily detect 648 // overlaps between ranges. 649 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 650 651 // Scan the ranges, computing the high values and removing empty ranges. 652 std::vector<llvm::APSInt> HiVals; 653 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 654 llvm::APSInt &LoVal = CaseRanges[i].first; 655 CaseStmt *CR = CaseRanges[i].second; 656 Expr *Hi = CR->getRHS(); 657 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 658 659 // Convert the value to the same width/sign as the condition. 660 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 661 Hi->getLocStart(), 662 diag::warn_case_value_overflow); 663 664 // If the LHS is not the same type as the condition, insert an implicit 665 // cast. 666 ImpCastExprToType(Hi, CondType, CK_IntegralCast); 667 CR->setRHS(Hi); 668 669 // If the low value is bigger than the high value, the case is empty. 670 if (LoVal > HiVal) { 671 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 672 << SourceRange(CR->getLHS()->getLocStart(), 673 Hi->getLocEnd()); 674 CaseRanges.erase(CaseRanges.begin()+i); 675 --i, --e; 676 continue; 677 } 678 679 if (ShouldCheckConstantCond && 680 LoVal <= ConstantCondValue && 681 ConstantCondValue <= HiVal) 682 ShouldCheckConstantCond = false; 683 684 HiVals.push_back(HiVal); 685 } 686 687 // Rescan the ranges, looking for overlap with singleton values and other 688 // ranges. Since the range list is sorted, we only need to compare case 689 // ranges with their neighbors. 690 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 691 llvm::APSInt &CRLo = CaseRanges[i].first; 692 llvm::APSInt &CRHi = HiVals[i]; 693 CaseStmt *CR = CaseRanges[i].second; 694 695 // Check to see whether the case range overlaps with any 696 // singleton cases. 697 CaseStmt *OverlapStmt = 0; 698 llvm::APSInt OverlapVal(32); 699 700 // Find the smallest value >= the lower bound. If I is in the 701 // case range, then we have overlap. 702 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 703 CaseVals.end(), CRLo, 704 CaseCompareFunctor()); 705 if (I != CaseVals.end() && I->first < CRHi) { 706 OverlapVal = I->first; // Found overlap with scalar. 707 OverlapStmt = I->second; 708 } 709 710 // Find the smallest value bigger than the upper bound. 711 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 712 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 713 OverlapVal = (I-1)->first; // Found overlap with scalar. 714 OverlapStmt = (I-1)->second; 715 } 716 717 // Check to see if this case stmt overlaps with the subsequent 718 // case range. 719 if (i && CRLo <= HiVals[i-1]) { 720 OverlapVal = HiVals[i-1]; // Found overlap with range. 721 OverlapStmt = CaseRanges[i-1].second; 722 } 723 724 if (OverlapStmt) { 725 // If we have a duplicate, report it. 726 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 727 << OverlapVal.toString(10); 728 Diag(OverlapStmt->getLHS()->getLocStart(), 729 diag::note_duplicate_case_prev); 730 // FIXME: We really want to remove the bogus case stmt from the 731 // substmt, but we have no way to do this right now. 732 CaseListIsErroneous = true; 733 } 734 } 735 } 736 737 // Complain if we have a constant condition and we didn't find a match. 738 if (!CaseListIsErroneous && ShouldCheckConstantCond) { 739 // TODO: it would be nice if we printed enums as enums, chars as 740 // chars, etc. 741 Diag(CondExpr->getExprLoc(), diag::warn_missing_case_for_condition) 742 << ConstantCondValue.toString(10) 743 << CondExpr->getSourceRange(); 744 } 745 746 // Check to see if switch is over an Enum and handles all of its 747 // values. We only issue a warning if there is not 'default:', but 748 // we still do the analysis to preserve this information in the AST 749 // (which can be used by flow-based analyes). 750 // 751 const EnumType *ET = CondTypeBeforePromotion->getAs<EnumType>(); 752 753 // If switch has default case, then ignore it. 754 if (!CaseListIsErroneous && !HasConstantCond && ET) { 755 const EnumDecl *ED = ET->getDecl(); 756 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 757 EnumValsTy EnumVals; 758 759 // Gather all enum values, set their type and sort them, 760 // allowing easier comparison with CaseVals. 761 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); 762 EDI != ED->enumerator_end(); ++EDI) { 763 llvm::APSInt Val = EDI->getInitVal(); 764 AdjustAPSInt(Val, CondWidth, CondIsSigned); 765 EnumVals.push_back(std::make_pair(Val, *EDI)); 766 } 767 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 768 EnumValsTy::iterator EIend = 769 std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 770 771 // See which case values aren't in enum. 772 // TODO: we might want to check whether case values are out of the 773 // enum even if we don't want to check whether all cases are handled. 774 if (!TheDefaultStmt) { 775 EnumValsTy::const_iterator EI = EnumVals.begin(); 776 for (CaseValsTy::const_iterator CI = CaseVals.begin(); 777 CI != CaseVals.end(); CI++) { 778 while (EI != EIend && EI->first < CI->first) 779 EI++; 780 if (EI == EIend || EI->first > CI->first) 781 Diag(CI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 782 << ED->getDeclName(); 783 } 784 // See which of case ranges aren't in enum 785 EI = EnumVals.begin(); 786 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); 787 RI != CaseRanges.end() && EI != EIend; RI++) { 788 while (EI != EIend && EI->first < RI->first) 789 EI++; 790 791 if (EI == EIend || EI->first != RI->first) { 792 Diag(RI->second->getLHS()->getExprLoc(), diag::warn_not_in_enum) 793 << ED->getDeclName(); 794 } 795 796 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 797 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 798 while (EI != EIend && EI->first < Hi) 799 EI++; 800 if (EI == EIend || EI->first != Hi) 801 Diag(RI->second->getRHS()->getExprLoc(), diag::warn_not_in_enum) 802 << ED->getDeclName(); 803 } 804 } 805 806 // Check which enum vals aren't in switch 807 CaseValsTy::const_iterator CI = CaseVals.begin(); 808 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 809 bool hasCasesNotInSwitch = false; 810 811 llvm::SmallVector<DeclarationName,8> UnhandledNames; 812 813 for (EnumValsTy::const_iterator EI = EnumVals.begin(); EI != EIend; EI++){ 814 // Drop unneeded case values 815 llvm::APSInt CIVal; 816 while (CI != CaseVals.end() && CI->first < EI->first) 817 CI++; 818 819 if (CI != CaseVals.end() && CI->first == EI->first) 820 continue; 821 822 // Drop unneeded case ranges 823 for (; RI != CaseRanges.end(); RI++) { 824 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 825 AdjustAPSInt(Hi, CondWidth, CondIsSigned); 826 if (EI->first <= Hi) 827 break; 828 } 829 830 if (RI == CaseRanges.end() || EI->first < RI->first) { 831 hasCasesNotInSwitch = true; 832 if (!TheDefaultStmt) 833 UnhandledNames.push_back(EI->second->getDeclName()); 834 } 835 } 836 837 // Produce a nice diagnostic if multiple values aren't handled. 838 switch (UnhandledNames.size()) { 839 case 0: break; 840 case 1: 841 Diag(CondExpr->getExprLoc(), diag::warn_missing_case1) 842 << UnhandledNames[0]; 843 break; 844 case 2: 845 Diag(CondExpr->getExprLoc(), diag::warn_missing_case2) 846 << UnhandledNames[0] << UnhandledNames[1]; 847 break; 848 case 3: 849 Diag(CondExpr->getExprLoc(), diag::warn_missing_case3) 850 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 851 break; 852 default: 853 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) 854 << (unsigned)UnhandledNames.size() 855 << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2]; 856 break; 857 } 858 859 if (!hasCasesNotInSwitch) 860 SS->setAllEnumCasesCovered(); 861 } 862 } 863 864 // FIXME: If the case list was broken is some way, we don't have a good system 865 // to patch it up. Instead, just return the whole substmt as broken. 866 if (CaseListIsErroneous) 867 return StmtError(); 868 869 return Owned(SS); 870} 871 872StmtResult 873Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 874 Decl *CondVar, Stmt *Body) { 875 ExprResult CondResult(Cond.release()); 876 877 VarDecl *ConditionVar = 0; 878 if (CondVar) { 879 ConditionVar = cast<VarDecl>(CondVar); 880 CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true); 881 if (CondResult.isInvalid()) 882 return StmtError(); 883 } 884 Expr *ConditionExpr = CondResult.take(); 885 if (!ConditionExpr) 886 return StmtError(); 887 888 DiagnoseUnusedExprResult(Body); 889 890 return Owned(new (Context) WhileStmt(Context, ConditionVar, ConditionExpr, 891 Body, WhileLoc)); 892} 893 894StmtResult 895Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body, 896 SourceLocation WhileLoc, SourceLocation CondLParen, 897 Expr *Cond, SourceLocation CondRParen) { 898 assert(Cond && "ActOnDoStmt(): missing expression"); 899 900 if (CheckBooleanCondition(Cond, DoLoc)) 901 return StmtError(); 902 903 CheckImplicitConversions(Cond, DoLoc); 904 ExprResult CondResult = MaybeCreateCXXExprWithTemporaries(Cond); 905 if (CondResult.isInvalid()) 906 return StmtError(); 907 Cond = CondResult.take(); 908 909 DiagnoseUnusedExprResult(Body); 910 911 return Owned(new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen)); 912} 913 914StmtResult 915Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 916 Stmt *First, FullExprArg second, Decl *secondVar, 917 FullExprArg third, 918 SourceLocation RParenLoc, Stmt *Body) { 919 if (!getLangOptions().CPlusPlus) { 920 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 921 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 922 // declare identifiers for objects having storage class 'auto' or 923 // 'register'. 924 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 925 DI!=DE; ++DI) { 926 VarDecl *VD = dyn_cast<VarDecl>(*DI); 927 if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage()) 928 VD = 0; 929 if (VD == 0) 930 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 931 // FIXME: mark decl erroneous! 932 } 933 } 934 } 935 936 ExprResult SecondResult(second.release()); 937 VarDecl *ConditionVar = 0; 938 if (secondVar) { 939 ConditionVar = cast<VarDecl>(secondVar); 940 SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true); 941 if (SecondResult.isInvalid()) 942 return StmtError(); 943 } 944 945 Expr *Third = third.release().takeAs<Expr>(); 946 947 DiagnoseUnusedExprResult(First); 948 DiagnoseUnusedExprResult(Third); 949 DiagnoseUnusedExprResult(Body); 950 951 return Owned(new (Context) ForStmt(Context, First, 952 SecondResult.take(), ConditionVar, 953 Third, Body, ForLoc, LParenLoc, 954 RParenLoc)); 955} 956 957StmtResult 958Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 959 SourceLocation LParenLoc, 960 Stmt *First, Expr *Second, 961 SourceLocation RParenLoc, Stmt *Body) { 962 if (First) { 963 QualType FirstType; 964 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 965 if (!DS->isSingleDecl()) 966 return StmtError(Diag((*DS->decl_begin())->getLocation(), 967 diag::err_toomany_element_decls)); 968 969 Decl *D = DS->getSingleDecl(); 970 FirstType = cast<ValueDecl>(D)->getType(); 971 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 972 // declare identifiers for objects having storage class 'auto' or 973 // 'register'. 974 VarDecl *VD = cast<VarDecl>(D); 975 if (VD->isLocalVarDecl() && !VD->hasLocalStorage()) 976 return StmtError(Diag(VD->getLocation(), 977 diag::err_non_variable_decl_in_for)); 978 } else { 979 Expr *FirstE = cast<Expr>(First); 980 if (!FirstE->isTypeDependent() && !FirstE->isLValue()) 981 return StmtError(Diag(First->getLocStart(), 982 diag::err_selector_element_not_lvalue) 983 << First->getSourceRange()); 984 985 FirstType = static_cast<Expr*>(First)->getType(); 986 } 987 if (!FirstType->isDependentType() && 988 !FirstType->isObjCObjectPointerType() && 989 !FirstType->isBlockPointerType()) 990 Diag(ForLoc, diag::err_selector_element_type) 991 << FirstType << First->getSourceRange(); 992 } 993 if (Second && !Second->isTypeDependent()) { 994 DefaultFunctionArrayLvalueConversion(Second); 995 QualType SecondType = Second->getType(); 996 if (!SecondType->isObjCObjectPointerType()) 997 Diag(ForLoc, diag::err_collection_expr_type) 998 << SecondType << Second->getSourceRange(); 999 else if (const ObjCObjectPointerType *OPT = 1000 SecondType->getAsObjCInterfacePointerType()) { 1001 llvm::SmallVector<IdentifierInfo *, 4> KeyIdents; 1002 IdentifierInfo* selIdent = 1003 &Context.Idents.get("countByEnumeratingWithState"); 1004 KeyIdents.push_back(selIdent); 1005 selIdent = &Context.Idents.get("objects"); 1006 KeyIdents.push_back(selIdent); 1007 selIdent = &Context.Idents.get("count"); 1008 KeyIdents.push_back(selIdent); 1009 Selector CSelector = Context.Selectors.getSelector(3, &KeyIdents[0]); 1010 if (ObjCInterfaceDecl *IDecl = OPT->getInterfaceDecl()) { 1011 if (!IDecl->isForwardDecl() && 1012 !IDecl->lookupInstanceMethod(CSelector)) { 1013 // Must further look into private implementation methods. 1014 if (!LookupPrivateInstanceMethod(CSelector, IDecl)) 1015 Diag(ForLoc, diag::warn_collection_expr_type) 1016 << SecondType << CSelector << Second->getSourceRange(); 1017 } 1018 } 1019 } 1020 } 1021 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 1022 ForLoc, RParenLoc)); 1023} 1024 1025StmtResult 1026Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 1027 IdentifierInfo *LabelII) { 1028 // Look up the record for this label identifier. 1029 LabelStmt *&LabelDecl = getCurFunction()->LabelMap[LabelII]; 1030 1031 getCurFunction()->setHasBranchIntoScope(); 1032 1033 // If we haven't seen this label yet, create a forward reference. 1034 if (LabelDecl == 0) 1035 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 1036 1037 LabelDecl->setUsed(); 1038 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 1039} 1040 1041StmtResult 1042Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 1043 Expr *E) { 1044 // Convert operand to void* 1045 if (!E->isTypeDependent()) { 1046 QualType ETy = E->getType(); 1047 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1048 AssignConvertType ConvTy = 1049 CheckSingleAssignmentConstraints(DestTy, E); 1050 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1051 return StmtError(); 1052 } 1053 1054 getCurFunction()->setHasIndirectGoto(); 1055 1056 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1057} 1058 1059StmtResult 1060Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1061 Scope *S = CurScope->getContinueParent(); 1062 if (!S) { 1063 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1064 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1065 } 1066 1067 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1068} 1069 1070StmtResult 1071Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1072 Scope *S = CurScope->getBreakParent(); 1073 if (!S) { 1074 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1075 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1076 } 1077 1078 return Owned(new (Context) BreakStmt(BreakLoc)); 1079} 1080 1081/// \brief Determine whether a return statement is a candidate for the named 1082/// return value optimization (C++0x 12.8p34, bullet 1). 1083/// 1084/// \param Ctx The context in which the return expression and type occur. 1085/// 1086/// \param RetType The return type of the function or block. 1087/// 1088/// \param RetExpr The expression being returned from the function or block. 1089/// 1090/// \returns The NRVO candidate variable, if the return statement may use the 1091/// NRVO, or NULL if there is no such candidate. 1092static const VarDecl *getNRVOCandidate(ASTContext &Ctx, QualType RetType, 1093 Expr *RetExpr) { 1094 QualType ExprType = RetExpr->getType(); 1095 // - in a return statement in a function with ... 1096 // ... a class return type ... 1097 if (!RetType->isRecordType()) 1098 return 0; 1099 // ... the same cv-unqualified type as the function return type ... 1100 if (!Ctx.hasSameUnqualifiedType(RetType, ExprType)) 1101 return 0; 1102 // ... the expression is the name of a non-volatile automatic object ... 1103 // We ignore parentheses here. 1104 // FIXME: Is this compliant? (Everyone else does it) 1105 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 1106 if (!DR) 1107 return 0; 1108 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1109 if (!VD) 1110 return 0; 1111 1112 if (VD->getKind() == Decl::Var && VD->hasLocalStorage() && 1113 !VD->getType()->isReferenceType() && !VD->hasAttr<BlocksAttr>() && 1114 !VD->getType().isVolatileQualified()) 1115 return VD; 1116 1117 return 0; 1118} 1119 1120/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1121/// 1122StmtResult 1123Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1124 // If this is the first return we've seen in the block, infer the type of 1125 // the block from it. 1126 BlockScopeInfo *CurBlock = getCurBlock(); 1127 if (CurBlock->ReturnType.isNull()) { 1128 if (RetValExp) { 1129 // Don't call UsualUnaryConversions(), since we don't want to do 1130 // integer promotions here. 1131 DefaultFunctionArrayLvalueConversion(RetValExp); 1132 CurBlock->ReturnType = RetValExp->getType(); 1133 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1134 // We have to remove a 'const' added to copied-in variable which was 1135 // part of the implementation spec. and not the actual qualifier for 1136 // the variable. 1137 if (CDRE->isConstQualAdded()) 1138 CurBlock->ReturnType.removeConst(); 1139 } 1140 } else 1141 CurBlock->ReturnType = Context.VoidTy; 1142 } 1143 QualType FnRetType = CurBlock->ReturnType; 1144 1145 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 1146 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1147 << getCurFunctionOrMethodDecl()->getDeclName(); 1148 return StmtError(); 1149 } 1150 1151 // Otherwise, verify that this result type matches the previous one. We are 1152 // pickier with blocks than for normal functions because we don't have GCC 1153 // compatibility to worry about here. 1154 ReturnStmt *Result = 0; 1155 if (CurBlock->ReturnType->isVoidType()) { 1156 if (RetValExp) { 1157 Diag(ReturnLoc, diag::err_return_block_has_expr); 1158 RetValExp = 0; 1159 } 1160 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1161 } else if (!RetValExp) { 1162 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1163 } else { 1164 const VarDecl *NRVOCandidate = 0; 1165 1166 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1167 // we have a non-void block with an expression, continue checking 1168 1169 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1170 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1171 // function return. 1172 1173 // In C++ the return statement is handled via a copy initialization. 1174 // the C version of which boils down to CheckSingleAssignmentConstraints. 1175 NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp); 1176 ExprResult Res = PerformCopyInitialization( 1177 InitializedEntity::InitializeResult(ReturnLoc, 1178 FnRetType, 1179 NRVOCandidate != 0), 1180 SourceLocation(), 1181 Owned(RetValExp)); 1182 if (Res.isInvalid()) { 1183 // FIXME: Cleanup temporaries here, anyway? 1184 return StmtError(); 1185 } 1186 1187 if (RetValExp) { 1188 CheckImplicitConversions(RetValExp, ReturnLoc); 1189 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1190 } 1191 1192 RetValExp = Res.takeAs<Expr>(); 1193 if (RetValExp) 1194 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1195 } 1196 1197 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1198 } 1199 1200 // If we need to check for the named return value optimization, save the 1201 // return statement in our scope for later processing. 1202 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1203 !CurContext->isDependentContext()) 1204 FunctionScopes.back()->Returns.push_back(Result); 1205 1206 return Owned(Result); 1207} 1208 1209StmtResult 1210Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1211 if (getCurBlock()) 1212 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1213 1214 QualType FnRetType; 1215 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1216 FnRetType = FD->getResultType(); 1217 if (FD->hasAttr<NoReturnAttr>() || 1218 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1219 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1220 << getCurFunctionOrMethodDecl()->getDeclName(); 1221 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1222 FnRetType = MD->getResultType(); 1223 else // If we don't have a function/method context, bail. 1224 return StmtError(); 1225 1226 ReturnStmt *Result = 0; 1227 if (FnRetType->isVoidType()) { 1228 if (RetValExp && !RetValExp->isTypeDependent()) { 1229 // C99 6.8.6.4p1 (ext_ since GCC warns) 1230 unsigned D = diag::ext_return_has_expr; 1231 if (RetValExp->getType()->isVoidType()) 1232 D = diag::ext_return_has_void_expr; 1233 1234 // return (some void expression); is legal in C++. 1235 if (D != diag::ext_return_has_void_expr || 1236 !getLangOptions().CPlusPlus) { 1237 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1238 Diag(ReturnLoc, D) 1239 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1240 << RetValExp->getSourceRange(); 1241 } 1242 1243 CheckImplicitConversions(RetValExp, ReturnLoc); 1244 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1245 } 1246 1247 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, 0); 1248 } else if (!RetValExp && !FnRetType->isDependentType()) { 1249 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1250 // C99 6.8.6.4p1 (ext_ since GCC warns) 1251 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1252 1253 if (FunctionDecl *FD = getCurFunctionDecl()) 1254 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1255 else 1256 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1257 Result = new (Context) ReturnStmt(ReturnLoc); 1258 } else { 1259 const VarDecl *NRVOCandidate = 0; 1260 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1261 // we have a non-void function with an expression, continue checking 1262 1263 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1264 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1265 // function return. 1266 1267 // In C++ the return statement is handled via a copy initialization. 1268 // the C version of which boils down to CheckSingleAssignmentConstraints. 1269 NRVOCandidate = getNRVOCandidate(Context, FnRetType, RetValExp); 1270 ExprResult Res = PerformCopyInitialization( 1271 InitializedEntity::InitializeResult(ReturnLoc, 1272 FnRetType, 1273 NRVOCandidate != 0), 1274 SourceLocation(), 1275 Owned(RetValExp)); 1276 if (Res.isInvalid()) { 1277 // FIXME: Cleanup temporaries here, anyway? 1278 return StmtError(); 1279 } 1280 1281 RetValExp = Res.takeAs<Expr>(); 1282 if (RetValExp) 1283 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1284 } 1285 1286 if (RetValExp) { 1287 CheckImplicitConversions(RetValExp, ReturnLoc); 1288 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1289 } 1290 Result = new (Context) ReturnStmt(ReturnLoc, RetValExp, NRVOCandidate); 1291 } 1292 1293 // If we need to check for the named return value optimization, save the 1294 // return statement in our scope for later processing. 1295 if (getLangOptions().CPlusPlus && FnRetType->isRecordType() && 1296 !CurContext->isDependentContext()) 1297 FunctionScopes.back()->Returns.push_back(Result); 1298 1299 return Owned(Result); 1300} 1301 1302/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1303/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1304/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1305/// provide a strong guidance to not use it. 1306/// 1307/// This method checks to see if the argument is an acceptable l-value and 1308/// returns false if it is a case we can handle. 1309static bool CheckAsmLValue(const Expr *E, Sema &S) { 1310 // Type dependent expressions will be checked during instantiation. 1311 if (E->isTypeDependent()) 1312 return false; 1313 1314 if (E->isLValue()) 1315 return false; // Cool, this is an lvalue. 1316 1317 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1318 // are supposed to allow. 1319 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1320 if (E != E2 && E2->isLValue()) { 1321 if (!S.getLangOptions().HeinousExtensions) 1322 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1323 << E->getSourceRange(); 1324 else 1325 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1326 << E->getSourceRange(); 1327 // Accept, even if we emitted an error diagnostic. 1328 return false; 1329 } 1330 1331 // None of the above, just randomly invalid non-lvalue. 1332 return true; 1333} 1334 1335 1336StmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1337 bool IsSimple, 1338 bool IsVolatile, 1339 unsigned NumOutputs, 1340 unsigned NumInputs, 1341 IdentifierInfo **Names, 1342 MultiExprArg constraints, 1343 MultiExprArg exprs, 1344 Expr *asmString, 1345 MultiExprArg clobbers, 1346 SourceLocation RParenLoc, 1347 bool MSAsm) { 1348 unsigned NumClobbers = clobbers.size(); 1349 StringLiteral **Constraints = 1350 reinterpret_cast<StringLiteral**>(constraints.get()); 1351 Expr **Exprs = exprs.get(); 1352 StringLiteral *AsmString = cast<StringLiteral>(asmString); 1353 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1354 1355 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1356 1357 // The parser verifies that there is a string literal here. 1358 if (AsmString->isWide()) 1359 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1360 << AsmString->getSourceRange()); 1361 1362 for (unsigned i = 0; i != NumOutputs; i++) { 1363 StringLiteral *Literal = Constraints[i]; 1364 if (Literal->isWide()) 1365 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1366 << Literal->getSourceRange()); 1367 1368 llvm::StringRef OutputName; 1369 if (Names[i]) 1370 OutputName = Names[i]->getName(); 1371 1372 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1373 if (!Context.Target.validateOutputConstraint(Info)) 1374 return StmtError(Diag(Literal->getLocStart(), 1375 diag::err_asm_invalid_output_constraint) 1376 << Info.getConstraintStr()); 1377 1378 // Check that the output exprs are valid lvalues. 1379 Expr *OutputExpr = Exprs[i]; 1380 if (CheckAsmLValue(OutputExpr, *this)) { 1381 return StmtError(Diag(OutputExpr->getLocStart(), 1382 diag::err_asm_invalid_lvalue_in_output) 1383 << OutputExpr->getSourceRange()); 1384 } 1385 1386 OutputConstraintInfos.push_back(Info); 1387 } 1388 1389 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1390 1391 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1392 StringLiteral *Literal = Constraints[i]; 1393 if (Literal->isWide()) 1394 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1395 << Literal->getSourceRange()); 1396 1397 llvm::StringRef InputName; 1398 if (Names[i]) 1399 InputName = Names[i]->getName(); 1400 1401 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1402 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1403 NumOutputs, Info)) { 1404 return StmtError(Diag(Literal->getLocStart(), 1405 diag::err_asm_invalid_input_constraint) 1406 << Info.getConstraintStr()); 1407 } 1408 1409 Expr *InputExpr = Exprs[i]; 1410 1411 // Only allow void types for memory constraints. 1412 if (Info.allowsMemory() && !Info.allowsRegister()) { 1413 if (CheckAsmLValue(InputExpr, *this)) 1414 return StmtError(Diag(InputExpr->getLocStart(), 1415 diag::err_asm_invalid_lvalue_in_input) 1416 << Info.getConstraintStr() 1417 << InputExpr->getSourceRange()); 1418 } 1419 1420 if (Info.allowsRegister()) { 1421 if (InputExpr->getType()->isVoidType()) { 1422 return StmtError(Diag(InputExpr->getLocStart(), 1423 diag::err_asm_invalid_type_in_input) 1424 << InputExpr->getType() << Info.getConstraintStr() 1425 << InputExpr->getSourceRange()); 1426 } 1427 } 1428 1429 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1430 1431 InputConstraintInfos.push_back(Info); 1432 } 1433 1434 // Check that the clobbers are valid. 1435 for (unsigned i = 0; i != NumClobbers; i++) { 1436 StringLiteral *Literal = Clobbers[i]; 1437 if (Literal->isWide()) 1438 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1439 << Literal->getSourceRange()); 1440 1441 llvm::StringRef Clobber = Literal->getString(); 1442 1443 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1444 return StmtError(Diag(Literal->getLocStart(), 1445 diag::err_asm_unknown_register_name) << Clobber); 1446 } 1447 1448 AsmStmt *NS = 1449 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1450 NumOutputs, NumInputs, Names, Constraints, Exprs, 1451 AsmString, NumClobbers, Clobbers, RParenLoc); 1452 // Validate the asm string, ensuring it makes sense given the operands we 1453 // have. 1454 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1455 unsigned DiagOffs; 1456 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1457 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1458 << AsmString->getSourceRange(); 1459 return StmtError(); 1460 } 1461 1462 // Validate tied input operands for type mismatches. 1463 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1464 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1465 1466 // If this is a tied constraint, verify that the output and input have 1467 // either exactly the same type, or that they are int/ptr operands with the 1468 // same size (int/long, int*/long, are ok etc). 1469 if (!Info.hasTiedOperand()) continue; 1470 1471 unsigned TiedTo = Info.getTiedOperand(); 1472 Expr *OutputExpr = Exprs[TiedTo]; 1473 Expr *InputExpr = Exprs[i+NumOutputs]; 1474 QualType InTy = InputExpr->getType(); 1475 QualType OutTy = OutputExpr->getType(); 1476 if (Context.hasSameType(InTy, OutTy)) 1477 continue; // All types can be tied to themselves. 1478 1479 // Decide if the input and output are in the same domain (integer/ptr or 1480 // floating point. 1481 enum AsmDomain { 1482 AD_Int, AD_FP, AD_Other 1483 } InputDomain, OutputDomain; 1484 1485 if (InTy->isIntegerType() || InTy->isPointerType()) 1486 InputDomain = AD_Int; 1487 else if (InTy->isRealFloatingType()) 1488 InputDomain = AD_FP; 1489 else 1490 InputDomain = AD_Other; 1491 1492 if (OutTy->isIntegerType() || OutTy->isPointerType()) 1493 OutputDomain = AD_Int; 1494 else if (OutTy->isRealFloatingType()) 1495 OutputDomain = AD_FP; 1496 else 1497 OutputDomain = AD_Other; 1498 1499 // They are ok if they are the same size and in the same domain. This 1500 // allows tying things like: 1501 // void* to int* 1502 // void* to int if they are the same size. 1503 // double to long double if they are the same size. 1504 // 1505 uint64_t OutSize = Context.getTypeSize(OutTy); 1506 uint64_t InSize = Context.getTypeSize(InTy); 1507 if (OutSize == InSize && InputDomain == OutputDomain && 1508 InputDomain != AD_Other) 1509 continue; 1510 1511 // If the smaller input/output operand is not mentioned in the asm string, 1512 // then we can promote it and the asm string won't notice. Check this 1513 // case now. 1514 bool SmallerValueMentioned = false; 1515 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1516 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1517 if (!Piece.isOperand()) continue; 1518 1519 // If this is a reference to the input and if the input was the smaller 1520 // one, then we have to reject this asm. 1521 if (Piece.getOperandNo() == i+NumOutputs) { 1522 if (InSize < OutSize) { 1523 SmallerValueMentioned = true; 1524 break; 1525 } 1526 } 1527 1528 // If this is a reference to the input and if the input was the smaller 1529 // one, then we have to reject this asm. 1530 if (Piece.getOperandNo() == TiedTo) { 1531 if (InSize > OutSize) { 1532 SmallerValueMentioned = true; 1533 break; 1534 } 1535 } 1536 } 1537 1538 // If the smaller value wasn't mentioned in the asm string, and if the 1539 // output was a register, just extend the shorter one to the size of the 1540 // larger one. 1541 if (!SmallerValueMentioned && InputDomain != AD_Other && 1542 OutputConstraintInfos[TiedTo].allowsRegister()) 1543 continue; 1544 1545 Diag(InputExpr->getLocStart(), 1546 diag::err_asm_tying_incompatible_types) 1547 << InTy << OutTy << OutputExpr->getSourceRange() 1548 << InputExpr->getSourceRange(); 1549 return StmtError(); 1550 } 1551 1552 return Owned(NS); 1553} 1554 1555StmtResult 1556Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1557 SourceLocation RParen, Decl *Parm, 1558 Stmt *Body) { 1559 VarDecl *Var = cast_or_null<VarDecl>(Parm); 1560 if (Var && Var->isInvalidDecl()) 1561 return StmtError(); 1562 1563 return Owned(new (Context) ObjCAtCatchStmt(AtLoc, RParen, Var, Body)); 1564} 1565 1566StmtResult 1567Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, Stmt *Body) { 1568 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, Body)); 1569} 1570 1571StmtResult 1572Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, Stmt *Try, 1573 MultiStmtArg CatchStmts, Stmt *Finally) { 1574 getCurFunction()->setHasBranchProtectedScope(); 1575 unsigned NumCatchStmts = CatchStmts.size(); 1576 return Owned(ObjCAtTryStmt::Create(Context, AtLoc, Try, 1577 CatchStmts.release(), 1578 NumCatchStmts, 1579 Finally)); 1580} 1581 1582StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, 1583 Expr *Throw) { 1584 if (Throw) { 1585 QualType ThrowType = Throw->getType(); 1586 // Make sure the expression type is an ObjC pointer or "void *". 1587 if (!ThrowType->isDependentType() && 1588 !ThrowType->isObjCObjectPointerType()) { 1589 const PointerType *PT = ThrowType->getAs<PointerType>(); 1590 if (!PT || !PT->getPointeeType()->isVoidType()) 1591 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1592 << Throw->getType() << Throw->getSourceRange()); 1593 } 1594 } 1595 1596 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, Throw)); 1597} 1598 1599StmtResult 1600Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw, 1601 Scope *CurScope) { 1602 if (!Throw) { 1603 // @throw without an expression designates a rethrow (which much occur 1604 // in the context of an @catch clause). 1605 Scope *AtCatchParent = CurScope; 1606 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1607 AtCatchParent = AtCatchParent->getParent(); 1608 if (!AtCatchParent) 1609 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1610 } 1611 1612 return BuildObjCAtThrowStmt(AtLoc, Throw); 1613} 1614 1615StmtResult 1616Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, Expr *SyncExpr, 1617 Stmt *SyncBody) { 1618 getCurFunction()->setHasBranchProtectedScope(); 1619 1620 // Make sure the expression type is an ObjC pointer or "void *". 1621 if (!SyncExpr->getType()->isDependentType() && 1622 !SyncExpr->getType()->isObjCObjectPointerType()) { 1623 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1624 if (!PT || !PT->getPointeeType()->isVoidType()) 1625 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1626 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1627 } 1628 1629 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, SyncExpr, SyncBody)); 1630} 1631 1632/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1633/// and creates a proper catch handler from them. 1634StmtResult 1635Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, Decl *ExDecl, 1636 Stmt *HandlerBlock) { 1637 // There's nothing to test that ActOnExceptionDecl didn't already test. 1638 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1639 cast_or_null<VarDecl>(ExDecl), 1640 HandlerBlock)); 1641} 1642 1643namespace { 1644 1645class TypeWithHandler { 1646 QualType t; 1647 CXXCatchStmt *stmt; 1648public: 1649 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1650 : t(type), stmt(statement) {} 1651 1652 // An arbitrary order is fine as long as it places identical 1653 // types next to each other. 1654 bool operator<(const TypeWithHandler &y) const { 1655 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1656 return true; 1657 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1658 return false; 1659 else 1660 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1661 } 1662 1663 bool operator==(const TypeWithHandler& other) const { 1664 return t == other.t; 1665 } 1666 1667 CXXCatchStmt *getCatchStmt() const { return stmt; } 1668 SourceLocation getTypeSpecStartLoc() const { 1669 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1670 } 1671}; 1672 1673} 1674 1675/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1676/// handlers and creates a try statement from them. 1677StmtResult 1678Sema::ActOnCXXTryBlock(SourceLocation TryLoc, Stmt *TryBlock, 1679 MultiStmtArg RawHandlers) { 1680 unsigned NumHandlers = RawHandlers.size(); 1681 assert(NumHandlers > 0 && 1682 "The parser shouldn't call this if there are no handlers."); 1683 Stmt **Handlers = RawHandlers.get(); 1684 1685 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1686 1687 for (unsigned i = 0; i < NumHandlers; ++i) { 1688 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1689 if (!Handler->getExceptionDecl()) { 1690 if (i < NumHandlers - 1) 1691 return StmtError(Diag(Handler->getLocStart(), 1692 diag::err_early_catch_all)); 1693 1694 continue; 1695 } 1696 1697 const QualType CaughtType = Handler->getCaughtType(); 1698 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1699 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1700 } 1701 1702 // Detect handlers for the same type as an earlier one. 1703 if (NumHandlers > 1) { 1704 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1705 1706 TypeWithHandler prev = TypesWithHandlers[0]; 1707 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1708 TypeWithHandler curr = TypesWithHandlers[i]; 1709 1710 if (curr == prev) { 1711 Diag(curr.getTypeSpecStartLoc(), 1712 diag::warn_exception_caught_by_earlier_handler) 1713 << curr.getCatchStmt()->getCaughtType().getAsString(); 1714 Diag(prev.getTypeSpecStartLoc(), 1715 diag::note_previous_exception_handler) 1716 << prev.getCatchStmt()->getCaughtType().getAsString(); 1717 } 1718 1719 prev = curr; 1720 } 1721 } 1722 1723 getCurFunction()->setHasBranchProtectedScope(); 1724 1725 // FIXME: We should detect handlers that cannot catch anything because an 1726 // earlier handler catches a superclass. Need to find a method that is not 1727 // quadratic for this. 1728 // Neither of these are explicitly forbidden, but every compiler detects them 1729 // and warns. 1730 1731 return Owned(CXXTryStmt::Create(Context, TryLoc, TryBlock, 1732 Handlers, NumHandlers)); 1733} 1734