SemaStmt.cpp revision 4dffad64c5c7106dc5ac506be94944299c8f7bc3
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 "Sema.h" 15#include "SemaInit.h" 16#include "clang/AST/APValue.h" 17#include "clang/AST/ASTContext.h" 18#include "clang/AST/DeclObjC.h" 19#include "clang/AST/ExprCXX.h" 20#include "clang/AST/ExprObjC.h" 21#include "clang/AST/StmtObjC.h" 22#include "clang/AST/StmtCXX.h" 23#include "clang/Lex/Preprocessor.h" 24#include "clang/Basic/TargetInfo.h" 25#include "llvm/ADT/STLExtras.h" 26#include "llvm/ADT/SmallVector.h" 27using namespace clang; 28 29Sema::OwningStmtResult Sema::ActOnExprStmt(FullExprArg expr) { 30 Expr *E = expr->takeAs<Expr>(); 31 assert(E && "ActOnExprStmt(): missing expression"); 32 if (E->getType()->isObjCInterfaceType()) { 33 if (LangOpts.ObjCNonFragileABI) 34 Diag(E->getLocEnd(), diag::err_indirection_requires_nonfragile_object) 35 << E->getType(); 36 else 37 Diag(E->getLocEnd(), diag::err_direct_interface_unsupported) 38 << E->getType(); 39 return StmtError(); 40 } 41 // C99 6.8.3p2: The expression in an expression statement is evaluated as a 42 // void expression for its side effects. Conversion to void allows any 43 // operand, even incomplete types. 44 45 // Same thing in for stmt first clause (when expr) and third clause. 46 return Owned(static_cast<Stmt*>(E)); 47} 48 49 50Sema::OwningStmtResult Sema::ActOnNullStmt(SourceLocation SemiLoc) { 51 return Owned(new (Context) NullStmt(SemiLoc)); 52} 53 54Sema::OwningStmtResult Sema::ActOnDeclStmt(DeclGroupPtrTy dg, 55 SourceLocation StartLoc, 56 SourceLocation EndLoc) { 57 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 58 59 // If we have an invalid decl, just return an error. 60 if (DG.isNull()) return StmtError(); 61 62 return Owned(new (Context) DeclStmt(DG, StartLoc, EndLoc)); 63} 64 65void Sema::ActOnForEachDeclStmt(DeclGroupPtrTy dg) { 66 DeclGroupRef DG = dg.getAsVal<DeclGroupRef>(); 67 68 // If we have an invalid decl, just return. 69 if (DG.isNull() || !DG.isSingleDecl()) return; 70 // suppress any potential 'unused variable' warning. 71 DG.getSingleDecl()->setUsed(); 72} 73 74void Sema::DiagnoseUnusedExprResult(const Stmt *S) { 75 const Expr *E = dyn_cast_or_null<Expr>(S); 76 if (!E) 77 return; 78 79 // Ignore expressions that have void type. 80 if (E->getType()->isVoidType()) 81 return; 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 if (const CXXZeroInitValueExpr *Zero = dyn_cast<CXXZeroInitValueExpr>(E)) { 99 if (const RecordType *RecordT = Zero->getType()->getAs<RecordType>()) 100 if (CXXRecordDecl *RecordD = dyn_cast<CXXRecordDecl>(RecordT->getDecl())) 101 if (!RecordD->hasTrivialDestructor()) 102 return; 103 } 104 105 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 106 // If the callee has attribute pure, const, or warn_unused_result, warn with 107 // a more specific message to make it clear what is happening. 108 if (const Decl *FD = CE->getCalleeDecl()) { 109 if (FD->getAttr<WarnUnusedResultAttr>()) { 110 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result"; 111 return; 112 } 113 if (FD->getAttr<PureAttr>()) { 114 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "pure"; 115 return; 116 } 117 if (FD->getAttr<ConstAttr>()) { 118 Diag(Loc, diag::warn_unused_call) << R1 << R2 << "const"; 119 return; 120 } 121 } 122 } 123 124 Diag(Loc, DiagID) << R1 << R2; 125} 126 127Action::OwningStmtResult 128Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R, 129 MultiStmtArg elts, bool isStmtExpr) { 130 unsigned NumElts = elts.size(); 131 Stmt **Elts = reinterpret_cast<Stmt**>(elts.release()); 132 // If we're in C89 mode, check that we don't have any decls after stmts. If 133 // so, emit an extension diagnostic. 134 if (!getLangOptions().C99 && !getLangOptions().CPlusPlus) { 135 // Note that __extension__ can be around a decl. 136 unsigned i = 0; 137 // Skip over all declarations. 138 for (; i != NumElts && isa<DeclStmt>(Elts[i]); ++i) 139 /*empty*/; 140 141 // We found the end of the list or a statement. Scan for another declstmt. 142 for (; i != NumElts && !isa<DeclStmt>(Elts[i]); ++i) 143 /*empty*/; 144 145 if (i != NumElts) { 146 Decl *D = *cast<DeclStmt>(Elts[i])->decl_begin(); 147 Diag(D->getLocation(), diag::ext_mixed_decls_code); 148 } 149 } 150 // Warn about unused expressions in statements. 151 for (unsigned i = 0; i != NumElts; ++i) { 152 // Ignore statements that are last in a statement expression. 153 if (isStmtExpr && i == NumElts - 1) 154 continue; 155 156 DiagnoseUnusedExprResult(Elts[i]); 157 } 158 159 return Owned(new (Context) CompoundStmt(Context, Elts, NumElts, L, R)); 160} 161 162Action::OwningStmtResult 163Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprArg lhsval, 164 SourceLocation DotDotDotLoc, ExprArg rhsval, 165 SourceLocation ColonLoc) { 166 assert((lhsval.get() != 0) && "missing expression in case statement"); 167 168 // C99 6.8.4.2p3: The expression shall be an integer constant. 169 // However, GCC allows any evaluatable integer expression. 170 Expr *LHSVal = static_cast<Expr*>(lhsval.get()); 171 if (!LHSVal->isTypeDependent() && !LHSVal->isValueDependent() && 172 VerifyIntegerConstantExpression(LHSVal)) 173 return StmtError(); 174 175 // GCC extension: The expression shall be an integer constant. 176 177 Expr *RHSVal = static_cast<Expr*>(rhsval.get()); 178 if (RHSVal && !RHSVal->isTypeDependent() && !RHSVal->isValueDependent() && 179 VerifyIntegerConstantExpression(RHSVal)) { 180 RHSVal = 0; // Recover by just forgetting about it. 181 rhsval = 0; 182 } 183 184 if (getSwitchStack().empty()) { 185 Diag(CaseLoc, diag::err_case_not_in_switch); 186 return StmtError(); 187 } 188 189 // Only now release the smart pointers. 190 lhsval.release(); 191 rhsval.release(); 192 CaseStmt *CS = new (Context) CaseStmt(LHSVal, RHSVal, CaseLoc, DotDotDotLoc, 193 ColonLoc); 194 getSwitchStack().back()->addSwitchCase(CS); 195 return Owned(CS); 196} 197 198/// ActOnCaseStmtBody - This installs a statement as the body of a case. 199void Sema::ActOnCaseStmtBody(StmtTy *caseStmt, StmtArg subStmt) { 200 CaseStmt *CS = static_cast<CaseStmt*>(caseStmt); 201 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 202 CS->setSubStmt(SubStmt); 203} 204 205Action::OwningStmtResult 206Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc, 207 StmtArg subStmt, Scope *CurScope) { 208 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 209 210 if (getSwitchStack().empty()) { 211 Diag(DefaultLoc, diag::err_default_not_in_switch); 212 return Owned(SubStmt); 213 } 214 215 DefaultStmt *DS = new (Context) DefaultStmt(DefaultLoc, ColonLoc, SubStmt); 216 getSwitchStack().back()->addSwitchCase(DS); 217 return Owned(DS); 218} 219 220Action::OwningStmtResult 221Sema::ActOnLabelStmt(SourceLocation IdentLoc, IdentifierInfo *II, 222 SourceLocation ColonLoc, StmtArg subStmt) { 223 Stmt *SubStmt = subStmt.takeAs<Stmt>(); 224 // Look up the record for this label identifier. 225 LabelStmt *&LabelDecl = getLabelMap()[II]; 226 227 // If not forward referenced or defined already, just create a new LabelStmt. 228 if (LabelDecl == 0) 229 return Owned(LabelDecl = new (Context) LabelStmt(IdentLoc, II, SubStmt)); 230 231 assert(LabelDecl->getID() == II && "Label mismatch!"); 232 233 // Otherwise, this label was either forward reference or multiply defined. If 234 // multiply defined, reject it now. 235 if (LabelDecl->getSubStmt()) { 236 Diag(IdentLoc, diag::err_redefinition_of_label) << LabelDecl->getID(); 237 Diag(LabelDecl->getIdentLoc(), diag::note_previous_definition); 238 return Owned(SubStmt); 239 } 240 241 // Otherwise, this label was forward declared, and we just found its real 242 // definition. Fill in the forward definition and return it. 243 LabelDecl->setIdentLoc(IdentLoc); 244 LabelDecl->setSubStmt(SubStmt); 245 return Owned(LabelDecl); 246} 247 248Action::OwningStmtResult 249Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, DeclPtrTy CondVar, 250 StmtArg ThenVal, SourceLocation ElseLoc, 251 StmtArg ElseVal) { 252 OwningExprResult CondResult(CondVal.release()); 253 254 VarDecl *ConditionVar = 0; 255 if (CondVar.get()) { 256 ConditionVar = CondVar.getAs<VarDecl>(); 257 CondResult = CheckConditionVariable(ConditionVar); 258 if (CondResult.isInvalid()) 259 return StmtError(); 260 } 261 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 262 if (!ConditionExpr) 263 return StmtError(); 264 265 if (CheckBooleanCondition(ConditionExpr, IfLoc)) { 266 CondResult = ConditionExpr; 267 return StmtError(); 268 } 269 270 Stmt *thenStmt = ThenVal.takeAs<Stmt>(); 271 DiagnoseUnusedExprResult(thenStmt); 272 273 // Warn if the if block has a null body without an else value. 274 // this helps prevent bugs due to typos, such as 275 // if (condition); 276 // do_stuff(); 277 if (!ElseVal.get()) { 278 if (NullStmt* stmt = dyn_cast<NullStmt>(thenStmt)) 279 Diag(stmt->getSemiLoc(), diag::warn_empty_if_body); 280 } 281 282 Stmt *elseStmt = ElseVal.takeAs<Stmt>(); 283 DiagnoseUnusedExprResult(elseStmt); 284 285 CondResult.release(); 286 return Owned(new (Context) IfStmt(IfLoc, ConditionVar, ConditionExpr, 287 thenStmt, ElseLoc, elseStmt)); 288} 289 290Action::OwningStmtResult 291Sema::ActOnStartOfSwitchStmt(FullExprArg cond, DeclPtrTy CondVar) { 292 OwningExprResult CondResult(cond.release()); 293 294 VarDecl *ConditionVar = 0; 295 if (CondVar.get()) { 296 ConditionVar = CondVar.getAs<VarDecl>(); 297 CondResult = CheckConditionVariable(ConditionVar); 298 if (CondResult.isInvalid()) 299 return StmtError(); 300 } 301 SwitchStmt *SS = new (Context) SwitchStmt(ConditionVar, 302 CondResult.takeAs<Expr>()); 303 getSwitchStack().push_back(SS); 304 return Owned(SS); 305} 306 307/// ConvertIntegerToTypeWarnOnOverflow - Convert the specified APInt to have 308/// the specified width and sign. If an overflow occurs, detect it and emit 309/// the specified diagnostic. 310void Sema::ConvertIntegerToTypeWarnOnOverflow(llvm::APSInt &Val, 311 unsigned NewWidth, bool NewSign, 312 SourceLocation Loc, 313 unsigned DiagID) { 314 // Perform a conversion to the promoted condition type if needed. 315 if (NewWidth > Val.getBitWidth()) { 316 // If this is an extension, just do it. 317 llvm::APSInt OldVal(Val); 318 Val.extend(NewWidth); 319 320 // If the input was signed and negative and the output is unsigned, 321 // warn. 322 if (!NewSign && OldVal.isSigned() && OldVal.isNegative()) 323 Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10); 324 325 Val.setIsSigned(NewSign); 326 } else if (NewWidth < Val.getBitWidth()) { 327 // If this is a truncation, check for overflow. 328 llvm::APSInt ConvVal(Val); 329 ConvVal.trunc(NewWidth); 330 ConvVal.setIsSigned(NewSign); 331 ConvVal.extend(Val.getBitWidth()); 332 ConvVal.setIsSigned(Val.isSigned()); 333 if (ConvVal != Val) 334 Diag(Loc, DiagID) << Val.toString(10) << ConvVal.toString(10); 335 336 // Regardless of whether a diagnostic was emitted, really do the 337 // truncation. 338 Val.trunc(NewWidth); 339 Val.setIsSigned(NewSign); 340 } else if (NewSign != Val.isSigned()) { 341 // Convert the sign to match the sign of the condition. This can cause 342 // overflow as well: unsigned(INTMIN) 343 llvm::APSInt OldVal(Val); 344 Val.setIsSigned(NewSign); 345 346 if (Val.isNegative()) // Sign bit changes meaning. 347 Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10); 348 } 349} 350 351namespace { 352 struct CaseCompareFunctor { 353 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 354 const llvm::APSInt &RHS) { 355 return LHS.first < RHS; 356 } 357 bool operator()(const std::pair<llvm::APSInt, CaseStmt*> &LHS, 358 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 359 return LHS.first < RHS.first; 360 } 361 bool operator()(const llvm::APSInt &LHS, 362 const std::pair<llvm::APSInt, CaseStmt*> &RHS) { 363 return LHS < RHS.first; 364 } 365 }; 366} 367 368/// CmpCaseVals - Comparison predicate for sorting case values. 369/// 370static bool CmpCaseVals(const std::pair<llvm::APSInt, CaseStmt*>& lhs, 371 const std::pair<llvm::APSInt, CaseStmt*>& rhs) { 372 if (lhs.first < rhs.first) 373 return true; 374 375 if (lhs.first == rhs.first && 376 lhs.second->getCaseLoc().getRawEncoding() 377 < rhs.second->getCaseLoc().getRawEncoding()) 378 return true; 379 return false; 380} 381 382/// CmpEnumVals - Comparison predicate for sorting enumeration values. 383/// 384static bool CmpEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 385 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 386{ 387 return lhs.first < rhs.first; 388} 389 390/// EqEnumVals - Comparison preficate for uniqing enumeration values. 391/// 392static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs, 393 const std::pair<llvm::APSInt, EnumConstantDecl*>& rhs) 394{ 395 return lhs.first == rhs.first; 396} 397 398/// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of 399/// potentially integral-promoted expression @p expr. 400static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) { 401 const ImplicitCastExpr *ImplicitCast = 402 dyn_cast_or_null<ImplicitCastExpr>(expr); 403 if (ImplicitCast != NULL) { 404 const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr(); 405 QualType TypeBeforePromotion = ExprBeforePromotion->getType(); 406 if (TypeBeforePromotion->isIntegralType()) { 407 return TypeBeforePromotion; 408 } 409 } 410 return expr->getType(); 411} 412 413/// \brief Check (and possibly convert) the condition in a switch 414/// statement in C++. 415static bool CheckCXXSwitchCondition(Sema &S, SourceLocation SwitchLoc, 416 Expr *&CondExpr) { 417 if (CondExpr->isTypeDependent()) 418 return false; 419 420 QualType CondType = CondExpr->getType(); 421 422 // C++ 6.4.2.p2: 423 // The condition shall be of integral type, enumeration type, or of a class 424 // type for which a single conversion function to integral or enumeration 425 // type exists (12.3). If the condition is of class type, the condition is 426 // converted by calling that conversion function, and the result of the 427 // conversion is used in place of the original condition for the remainder 428 // of this section. Integral promotions are performed. 429 430 // Make sure that the condition expression has a complete type, 431 // otherwise we'll never find any conversions. 432 if (S.RequireCompleteType(SwitchLoc, CondType, 433 PDiag(diag::err_switch_incomplete_class_type) 434 << CondExpr->getSourceRange())) 435 return true; 436 437 llvm::SmallVector<CXXConversionDecl *, 4> ViableConversions; 438 llvm::SmallVector<CXXConversionDecl *, 4> ExplicitConversions; 439 if (const RecordType *RecordTy = CondType->getAs<RecordType>()) { 440 const UnresolvedSetImpl *Conversions 441 = cast<CXXRecordDecl>(RecordTy->getDecl()) 442 ->getVisibleConversionFunctions(); 443 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 444 E = Conversions->end(); I != E; ++I) { 445 if (CXXConversionDecl *Conversion = dyn_cast<CXXConversionDecl>(*I)) 446 if (Conversion->getConversionType().getNonReferenceType() 447 ->isIntegralType()) { 448 if (Conversion->isExplicit()) 449 ExplicitConversions.push_back(Conversion); 450 else 451 ViableConversions.push_back(Conversion); 452 } 453 } 454 455 switch (ViableConversions.size()) { 456 case 0: 457 if (ExplicitConversions.size() == 1) { 458 // The user probably meant to invoke the given explicit 459 // conversion; use it. 460 QualType ConvTy 461 = ExplicitConversions[0]->getConversionType() 462 .getNonReferenceType(); 463 std::string TypeStr; 464 ConvTy.getAsStringInternal(TypeStr, S.Context.PrintingPolicy); 465 466 S.Diag(SwitchLoc, diag::err_switch_explicit_conversion) 467 << CondType << ConvTy << CondExpr->getSourceRange() 468 << CodeModificationHint::CreateInsertion(CondExpr->getLocStart(), 469 "static_cast<" + TypeStr + ">(") 470 << CodeModificationHint::CreateInsertion( 471 S.PP.getLocForEndOfToken(CondExpr->getLocEnd()), 472 ")"); 473 S.Diag(ExplicitConversions[0]->getLocation(), 474 diag::note_switch_conversion) 475 << ConvTy->isEnumeralType() << ConvTy; 476 477 // If we aren't in a SFINAE context, build a call to the 478 // explicit conversion function. 479 if (S.isSFINAEContext()) 480 return true; 481 482 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, ExplicitConversions[0]); 483 } 484 485 // We'll complain below about a non-integral condition type. 486 break; 487 488 case 1: 489 // Apply this conversion. 490 CondExpr = S.BuildCXXMemberCallExpr(CondExpr, ViableConversions[0]); 491 break; 492 493 default: 494 S.Diag(SwitchLoc, diag::err_switch_multiple_conversions) 495 << CondType << CondExpr->getSourceRange(); 496 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) { 497 QualType ConvTy 498 = ViableConversions[I]->getConversionType().getNonReferenceType(); 499 S.Diag(ViableConversions[I]->getLocation(), 500 diag::note_switch_conversion) 501 << ConvTy->isEnumeralType() << ConvTy; 502 } 503 return true; 504 } 505 } 506 507 return false; 508} 509 510/// ActOnSwitchBodyError - This is called if there is an error parsing the 511/// body of the switch stmt instead of ActOnFinishSwitchStmt. 512void Sema::ActOnSwitchBodyError(SourceLocation SwitchLoc, StmtArg Switch, 513 StmtArg Body) { 514 // Keep the switch stack balanced. 515 assert(getSwitchStack().back() == (SwitchStmt*)Switch.get() && 516 "switch stack missing push/pop!"); 517 getSwitchStack().pop_back(); 518} 519 520Action::OwningStmtResult 521Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch, 522 StmtArg Body) { 523 Stmt *BodyStmt = Body.takeAs<Stmt>(); 524 525 SwitchStmt *SS = getSwitchStack().back(); 526 assert(SS == (SwitchStmt*)Switch.get() && "switch stack missing push/pop!"); 527 528 SS->setBody(BodyStmt, SwitchLoc); 529 getSwitchStack().pop_back(); 530 531 if (SS->getCond() == 0) { 532 SS->Destroy(Context); 533 return StmtError(); 534 } 535 536 Expr *CondExpr = SS->getCond(); 537 QualType CondTypeBeforePromotion = 538 GetTypeBeforeIntegralPromotion(CondExpr); 539 540 if (getLangOptions().CPlusPlus && 541 CheckCXXSwitchCondition(*this, SwitchLoc, CondExpr)) 542 return StmtError(); 543 544 // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr. 545 UsualUnaryConversions(CondExpr); 546 QualType CondType = CondExpr->getType(); 547 SS->setCond(CondExpr); 548 549 // C++ 6.4.2.p2: 550 // Integral promotions are performed (on the switch condition). 551 // 552 // A case value unrepresentable by the original switch condition 553 // type (before the promotion) doesn't make sense, even when it can 554 // be represented by the promoted type. Therefore we need to find 555 // the pre-promotion type of the switch condition. 556 if (!CondExpr->isTypeDependent()) { 557 if (!CondType->isIntegerType()) { // C99 6.8.4.2p1 558 Diag(SwitchLoc, diag::err_typecheck_statement_requires_integer) 559 << CondType << CondExpr->getSourceRange(); 560 return StmtError(); 561 } 562 563 if (CondTypeBeforePromotion->isBooleanType()) { 564 // switch(bool_expr) {...} is often a programmer error, e.g. 565 // switch(n && mask) { ... } // Doh - should be "n & mask". 566 // One can always use an if statement instead of switch(bool_expr). 567 Diag(SwitchLoc, diag::warn_bool_switch_condition) 568 << CondExpr->getSourceRange(); 569 } 570 } 571 572 // Get the bitwidth of the switched-on value before promotions. We must 573 // convert the integer case values to this width before comparison. 574 bool HasDependentValue 575 = CondExpr->isTypeDependent() || CondExpr->isValueDependent(); 576 unsigned CondWidth 577 = HasDependentValue? 0 578 : static_cast<unsigned>(Context.getTypeSize(CondTypeBeforePromotion)); 579 bool CondIsSigned = CondTypeBeforePromotion->isSignedIntegerType(); 580 581 // Accumulate all of the case values in a vector so that we can sort them 582 // and detect duplicates. This vector contains the APInt for the case after 583 // it has been converted to the condition type. 584 typedef llvm::SmallVector<std::pair<llvm::APSInt, CaseStmt*>, 64> CaseValsTy; 585 CaseValsTy CaseVals; 586 587 // Keep track of any GNU case ranges we see. The APSInt is the low value. 588 typedef std::vector<std::pair<llvm::APSInt, CaseStmt*> > CaseRangesTy; 589 CaseRangesTy CaseRanges; 590 591 DefaultStmt *TheDefaultStmt = 0; 592 593 bool CaseListIsErroneous = false; 594 595 for (SwitchCase *SC = SS->getSwitchCaseList(); SC && !HasDependentValue; 596 SC = SC->getNextSwitchCase()) { 597 598 if (DefaultStmt *DS = dyn_cast<DefaultStmt>(SC)) { 599 if (TheDefaultStmt) { 600 Diag(DS->getDefaultLoc(), diag::err_multiple_default_labels_defined); 601 Diag(TheDefaultStmt->getDefaultLoc(), diag::note_duplicate_case_prev); 602 603 // FIXME: Remove the default statement from the switch block so that 604 // we'll return a valid AST. This requires recursing down the AST and 605 // finding it, not something we are set up to do right now. For now, 606 // just lop the entire switch stmt out of the AST. 607 CaseListIsErroneous = true; 608 } 609 TheDefaultStmt = DS; 610 611 } else { 612 CaseStmt *CS = cast<CaseStmt>(SC); 613 614 // We already verified that the expression has a i-c-e value (C99 615 // 6.8.4.2p3) - get that value now. 616 Expr *Lo = CS->getLHS(); 617 618 if (Lo->isTypeDependent() || Lo->isValueDependent()) { 619 HasDependentValue = true; 620 break; 621 } 622 623 llvm::APSInt LoVal = Lo->EvaluateAsInt(Context); 624 625 // Convert the value to the same width/sign as the condition. 626 ConvertIntegerToTypeWarnOnOverflow(LoVal, CondWidth, CondIsSigned, 627 CS->getLHS()->getLocStart(), 628 diag::warn_case_value_overflow); 629 630 // If the LHS is not the same type as the condition, insert an implicit 631 // cast. 632 ImpCastExprToType(Lo, CondType, CastExpr::CK_IntegralCast); 633 CS->setLHS(Lo); 634 635 // If this is a case range, remember it in CaseRanges, otherwise CaseVals. 636 if (CS->getRHS()) { 637 if (CS->getRHS()->isTypeDependent() || 638 CS->getRHS()->isValueDependent()) { 639 HasDependentValue = true; 640 break; 641 } 642 CaseRanges.push_back(std::make_pair(LoVal, CS)); 643 } else 644 CaseVals.push_back(std::make_pair(LoVal, CS)); 645 } 646 } 647 648 if (!HasDependentValue) { 649 // Sort all the scalar case values so we can easily detect duplicates. 650 std::stable_sort(CaseVals.begin(), CaseVals.end(), CmpCaseVals); 651 652 if (!CaseVals.empty()) { 653 for (unsigned i = 0, e = CaseVals.size()-1; i != e; ++i) { 654 if (CaseVals[i].first == CaseVals[i+1].first) { 655 // If we have a duplicate, report it. 656 Diag(CaseVals[i+1].second->getLHS()->getLocStart(), 657 diag::err_duplicate_case) << CaseVals[i].first.toString(10); 658 Diag(CaseVals[i].second->getLHS()->getLocStart(), 659 diag::note_duplicate_case_prev); 660 // FIXME: We really want to remove the bogus case stmt from the 661 // substmt, but we have no way to do this right now. 662 CaseListIsErroneous = true; 663 } 664 } 665 } 666 667 // Detect duplicate case ranges, which usually don't exist at all in 668 // the first place. 669 if (!CaseRanges.empty()) { 670 // Sort all the case ranges by their low value so we can easily detect 671 // overlaps between ranges. 672 std::stable_sort(CaseRanges.begin(), CaseRanges.end()); 673 674 // Scan the ranges, computing the high values and removing empty ranges. 675 std::vector<llvm::APSInt> HiVals; 676 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 677 CaseStmt *CR = CaseRanges[i].second; 678 Expr *Hi = CR->getRHS(); 679 llvm::APSInt HiVal = Hi->EvaluateAsInt(Context); 680 681 // Convert the value to the same width/sign as the condition. 682 ConvertIntegerToTypeWarnOnOverflow(HiVal, CondWidth, CondIsSigned, 683 CR->getRHS()->getLocStart(), 684 diag::warn_case_value_overflow); 685 686 // If the LHS is not the same type as the condition, insert an implicit 687 // cast. 688 ImpCastExprToType(Hi, CondType, CastExpr::CK_IntegralCast); 689 CR->setRHS(Hi); 690 691 // If the low value is bigger than the high value, the case is empty. 692 if (CaseRanges[i].first > HiVal) { 693 Diag(CR->getLHS()->getLocStart(), diag::warn_case_empty_range) 694 << SourceRange(CR->getLHS()->getLocStart(), 695 CR->getRHS()->getLocEnd()); 696 CaseRanges.erase(CaseRanges.begin()+i); 697 --i, --e; 698 continue; 699 } 700 HiVals.push_back(HiVal); 701 } 702 703 // Rescan the ranges, looking for overlap with singleton values and other 704 // ranges. Since the range list is sorted, we only need to compare case 705 // ranges with their neighbors. 706 for (unsigned i = 0, e = CaseRanges.size(); i != e; ++i) { 707 llvm::APSInt &CRLo = CaseRanges[i].first; 708 llvm::APSInt &CRHi = HiVals[i]; 709 CaseStmt *CR = CaseRanges[i].second; 710 711 // Check to see whether the case range overlaps with any 712 // singleton cases. 713 CaseStmt *OverlapStmt = 0; 714 llvm::APSInt OverlapVal(32); 715 716 // Find the smallest value >= the lower bound. If I is in the 717 // case range, then we have overlap. 718 CaseValsTy::iterator I = std::lower_bound(CaseVals.begin(), 719 CaseVals.end(), CRLo, 720 CaseCompareFunctor()); 721 if (I != CaseVals.end() && I->first < CRHi) { 722 OverlapVal = I->first; // Found overlap with scalar. 723 OverlapStmt = I->second; 724 } 725 726 // Find the smallest value bigger than the upper bound. 727 I = std::upper_bound(I, CaseVals.end(), CRHi, CaseCompareFunctor()); 728 if (I != CaseVals.begin() && (I-1)->first >= CRLo) { 729 OverlapVal = (I-1)->first; // Found overlap with scalar. 730 OverlapStmt = (I-1)->second; 731 } 732 733 // Check to see if this case stmt overlaps with the subsequent 734 // case range. 735 if (i && CRLo <= HiVals[i-1]) { 736 OverlapVal = HiVals[i-1]; // Found overlap with range. 737 OverlapStmt = CaseRanges[i-1].second; 738 } 739 740 if (OverlapStmt) { 741 // If we have a duplicate, report it. 742 Diag(CR->getLHS()->getLocStart(), diag::err_duplicate_case) 743 << OverlapVal.toString(10); 744 Diag(OverlapStmt->getLHS()->getLocStart(), 745 diag::note_duplicate_case_prev); 746 // FIXME: We really want to remove the bogus case stmt from the 747 // substmt, but we have no way to do this right now. 748 CaseListIsErroneous = true; 749 } 750 } 751 } 752 753 // Check to see if switch is over an Enum and handles all of its 754 // values 755 const EnumType* ET = dyn_cast<EnumType>(CondTypeBeforePromotion); 756 // If switch has default case, then ignore it. 757 if (!CaseListIsErroneous && !TheDefaultStmt && ET) { 758 const EnumDecl *ED = ET->getDecl(); 759 typedef llvm::SmallVector<std::pair<llvm::APSInt, EnumConstantDecl*>, 64> EnumValsTy; 760 EnumValsTy EnumVals; 761 762 // Gather all enum values, set their type and sort them, allowing easier comparison 763 // with CaseVals. 764 for (EnumDecl::enumerator_iterator EDI = ED->enumerator_begin(); EDI != ED->enumerator_end(); EDI++) { 765 llvm::APSInt Val = (*EDI)->getInitVal(); 766 if(Val.getBitWidth() < CondWidth) 767 Val.extend(CondWidth); 768 Val.setIsSigned(CondIsSigned); 769 EnumVals.push_back(std::make_pair(Val, (*EDI))); 770 } 771 std::stable_sort(EnumVals.begin(), EnumVals.end(), CmpEnumVals); 772 EnumValsTy::iterator EIend = std::unique(EnumVals.begin(), EnumVals.end(), EqEnumVals); 773 // See which case values aren't in enum 774 EnumValsTy::const_iterator EI = EnumVals.begin(); 775 for (CaseValsTy::const_iterator CI = CaseVals.begin(); CI != CaseVals.end(); CI++) { 776 while (EI != EIend && EI->first < CI->first) 777 EI++; 778 if (EI == EIend || EI->first > CI->first) 779 Diag(CI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 780 } 781 // See which of case ranges aren't in enum 782 EI = EnumVals.begin(); 783 for (CaseRangesTy::const_iterator RI = CaseRanges.begin(); RI != CaseRanges.end() && EI != EIend; RI++) { 784 while (EI != EIend && EI->first < RI->first) 785 EI++; 786 787 if (EI == EIend || EI->first != RI->first) { 788 Diag(RI->second->getLHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 789 } 790 791 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 792 while (EI != EIend && EI->first < Hi) 793 EI++; 794 if (EI == EIend || EI->first != Hi) 795 Diag(RI->second->getRHS()->getExprLoc(), diag::not_in_enum) << ED->getDeclName(); 796 } 797 //Check which enum vals aren't in switch 798 CaseValsTy::const_iterator CI = CaseVals.begin(); 799 CaseRangesTy::const_iterator RI = CaseRanges.begin(); 800 EI = EnumVals.begin(); 801 for (; EI != EIend; EI++) { 802 //Drop unneeded case values 803 llvm::APSInt CIVal; 804 while (CI != CaseVals.end() && CI->first < EI->first) 805 CI++; 806 807 if (CI != CaseVals.end() && CI->first == EI->first) 808 continue; 809 810 //Drop unneeded case ranges 811 for (; RI != CaseRanges.end(); RI++) { 812 llvm::APSInt Hi = RI->second->getRHS()->EvaluateAsInt(Context); 813 if (EI->first <= Hi) 814 break; 815 } 816 817 if (RI == CaseRanges.end() || EI->first < RI->first) 818 Diag(CondExpr->getExprLoc(), diag::warn_missing_cases) << EI->second->getDeclName(); 819 } 820 } 821 } 822 823 // FIXME: If the case list was broken is some way, we don't have a good system 824 // to patch it up. Instead, just return the whole substmt as broken. 825 if (CaseListIsErroneous) 826 return StmtError(); 827 828 Switch.release(); 829 return Owned(SS); 830} 831 832Action::OwningStmtResult 833Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond, 834 DeclPtrTy CondVar, StmtArg Body) { 835 OwningExprResult CondResult(Cond.release()); 836 837 VarDecl *ConditionVar = 0; 838 if (CondVar.get()) { 839 ConditionVar = CondVar.getAs<VarDecl>(); 840 CondResult = CheckConditionVariable(ConditionVar); 841 if (CondResult.isInvalid()) 842 return StmtError(); 843 } 844 Expr *ConditionExpr = CondResult.takeAs<Expr>(); 845 if (!ConditionExpr) 846 return StmtError(); 847 848 if (CheckBooleanCondition(ConditionExpr, WhileLoc)) { 849 CondResult = ConditionExpr; 850 return StmtError(); 851 } 852 853 Stmt *bodyStmt = Body.takeAs<Stmt>(); 854 DiagnoseUnusedExprResult(bodyStmt); 855 856 CondResult.release(); 857 return Owned(new (Context) WhileStmt(ConditionVar, ConditionExpr, bodyStmt, 858 WhileLoc)); 859} 860 861Action::OwningStmtResult 862Sema::ActOnDoStmt(SourceLocation DoLoc, StmtArg Body, 863 SourceLocation WhileLoc, SourceLocation CondLParen, 864 ExprArg Cond, SourceLocation CondRParen) { 865 Expr *condExpr = Cond.takeAs<Expr>(); 866 assert(condExpr && "ActOnDoStmt(): missing expression"); 867 868 if (CheckBooleanCondition(condExpr, DoLoc)) { 869 Cond = condExpr; 870 return StmtError(); 871 } 872 873 Stmt *bodyStmt = Body.takeAs<Stmt>(); 874 DiagnoseUnusedExprResult(bodyStmt); 875 876 Cond.release(); 877 return Owned(new (Context) DoStmt(bodyStmt, condExpr, DoLoc, 878 WhileLoc, CondRParen)); 879} 880 881Action::OwningStmtResult 882Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc, 883 StmtArg first, FullExprArg second, DeclPtrTy secondVar, 884 FullExprArg third, 885 SourceLocation RParenLoc, StmtArg body) { 886 Stmt *First = static_cast<Stmt*>(first.get()); 887 888 if (!getLangOptions().CPlusPlus) { 889 if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) { 890 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 891 // declare identifiers for objects having storage class 'auto' or 892 // 'register'. 893 for (DeclStmt::decl_iterator DI=DS->decl_begin(), DE=DS->decl_end(); 894 DI!=DE; ++DI) { 895 VarDecl *VD = dyn_cast<VarDecl>(*DI); 896 if (VD && VD->isBlockVarDecl() && !VD->hasLocalStorage()) 897 VD = 0; 898 if (VD == 0) 899 Diag((*DI)->getLocation(), diag::err_non_variable_decl_in_for); 900 // FIXME: mark decl erroneous! 901 } 902 } 903 } 904 905 OwningExprResult SecondResult(second.release()); 906 VarDecl *ConditionVar = 0; 907 if (secondVar.get()) { 908 ConditionVar = secondVar.getAs<VarDecl>(); 909 SecondResult = CheckConditionVariable(ConditionVar); 910 if (SecondResult.isInvalid()) 911 return StmtError(); 912 } 913 914 Expr *Second = SecondResult.takeAs<Expr>(); 915 if (Second && CheckBooleanCondition(Second, ForLoc)) { 916 SecondResult = Second; 917 return StmtError(); 918 } 919 920 Expr *Third = third.release().takeAs<Expr>(); 921 Stmt *Body = static_cast<Stmt*>(body.get()); 922 923 DiagnoseUnusedExprResult(First); 924 DiagnoseUnusedExprResult(Third); 925 DiagnoseUnusedExprResult(Body); 926 927 first.release(); 928 body.release(); 929 return Owned(new (Context) ForStmt(First, Second, ConditionVar, Third, Body, 930 ForLoc, LParenLoc, RParenLoc)); 931} 932 933Action::OwningStmtResult 934Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc, 935 SourceLocation LParenLoc, 936 StmtArg first, ExprArg second, 937 SourceLocation RParenLoc, StmtArg body) { 938 Stmt *First = static_cast<Stmt*>(first.get()); 939 Expr *Second = static_cast<Expr*>(second.get()); 940 Stmt *Body = static_cast<Stmt*>(body.get()); 941 if (First) { 942 QualType FirstType; 943 if (DeclStmt *DS = dyn_cast<DeclStmt>(First)) { 944 if (!DS->isSingleDecl()) 945 return StmtError(Diag((*DS->decl_begin())->getLocation(), 946 diag::err_toomany_element_decls)); 947 948 Decl *D = DS->getSingleDecl(); 949 FirstType = cast<ValueDecl>(D)->getType(); 950 // C99 6.8.5p3: The declaration part of a 'for' statement shall only 951 // declare identifiers for objects having storage class 'auto' or 952 // 'register'. 953 VarDecl *VD = cast<VarDecl>(D); 954 if (VD->isBlockVarDecl() && !VD->hasLocalStorage()) 955 return StmtError(Diag(VD->getLocation(), 956 diag::err_non_variable_decl_in_for)); 957 } else { 958 if (cast<Expr>(First)->isLvalue(Context) != Expr::LV_Valid) 959 return StmtError(Diag(First->getLocStart(), 960 diag::err_selector_element_not_lvalue) 961 << First->getSourceRange()); 962 963 FirstType = static_cast<Expr*>(First)->getType(); 964 } 965 if (!FirstType->isObjCObjectPointerType() && 966 !FirstType->isBlockPointerType()) 967 Diag(ForLoc, diag::err_selector_element_type) 968 << FirstType << First->getSourceRange(); 969 } 970 if (Second) { 971 DefaultFunctionArrayLvalueConversion(Second); 972 QualType SecondType = Second->getType(); 973 if (!SecondType->isObjCObjectPointerType()) 974 Diag(ForLoc, diag::err_collection_expr_type) 975 << SecondType << Second->getSourceRange(); 976 } 977 first.release(); 978 second.release(); 979 body.release(); 980 return Owned(new (Context) ObjCForCollectionStmt(First, Second, Body, 981 ForLoc, RParenLoc)); 982} 983 984Action::OwningStmtResult 985Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc, 986 IdentifierInfo *LabelII) { 987 // Look up the record for this label identifier. 988 LabelStmt *&LabelDecl = getLabelMap()[LabelII]; 989 990 // If we haven't seen this label yet, create a forward reference. 991 if (LabelDecl == 0) 992 LabelDecl = new (Context) LabelStmt(LabelLoc, LabelII, 0); 993 994 return Owned(new (Context) GotoStmt(LabelDecl, GotoLoc, LabelLoc)); 995} 996 997Action::OwningStmtResult 998Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc, 999 ExprArg DestExp) { 1000 // Convert operand to void* 1001 Expr* E = DestExp.takeAs<Expr>(); 1002 if (!E->isTypeDependent()) { 1003 QualType ETy = E->getType(); 1004 QualType DestTy = Context.getPointerType(Context.VoidTy.withConst()); 1005 AssignConvertType ConvTy = 1006 CheckSingleAssignmentConstraints(DestTy, E); 1007 if (DiagnoseAssignmentResult(ConvTy, StarLoc, DestTy, ETy, E, AA_Passing)) 1008 return StmtError(); 1009 } 1010 return Owned(new (Context) IndirectGotoStmt(GotoLoc, StarLoc, E)); 1011} 1012 1013Action::OwningStmtResult 1014Sema::ActOnContinueStmt(SourceLocation ContinueLoc, Scope *CurScope) { 1015 Scope *S = CurScope->getContinueParent(); 1016 if (!S) { 1017 // C99 6.8.6.2p1: A break shall appear only in or as a loop body. 1018 return StmtError(Diag(ContinueLoc, diag::err_continue_not_in_loop)); 1019 } 1020 1021 return Owned(new (Context) ContinueStmt(ContinueLoc)); 1022} 1023 1024Action::OwningStmtResult 1025Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) { 1026 Scope *S = CurScope->getBreakParent(); 1027 if (!S) { 1028 // C99 6.8.6.3p1: A break shall appear only in or as a switch/loop body. 1029 return StmtError(Diag(BreakLoc, diag::err_break_not_in_loop_or_switch)); 1030 } 1031 1032 return Owned(new (Context) BreakStmt(BreakLoc)); 1033} 1034 1035/// ActOnBlockReturnStmt - Utility routine to figure out block's return type. 1036/// 1037Action::OwningStmtResult 1038Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) { 1039 // If this is the first return we've seen in the block, infer the type of 1040 // the block from it. 1041 if (CurBlock->ReturnType.isNull()) { 1042 if (RetValExp) { 1043 // Don't call UsualUnaryConversions(), since we don't want to do 1044 // integer promotions here. 1045 DefaultFunctionArrayLvalueConversion(RetValExp); 1046 CurBlock->ReturnType = RetValExp->getType(); 1047 if (BlockDeclRefExpr *CDRE = dyn_cast<BlockDeclRefExpr>(RetValExp)) { 1048 // We have to remove a 'const' added to copied-in variable which was 1049 // part of the implementation spec. and not the actual qualifier for 1050 // the variable. 1051 if (CDRE->isConstQualAdded()) 1052 CurBlock->ReturnType.removeConst(); 1053 } 1054 } else 1055 CurBlock->ReturnType = Context.VoidTy; 1056 } 1057 QualType FnRetType = CurBlock->ReturnType; 1058 1059 if (CurBlock->TheDecl->hasAttr<NoReturnAttr>()) { 1060 Diag(ReturnLoc, diag::err_noreturn_block_has_return_expr) 1061 << getCurFunctionOrMethodDecl()->getDeclName(); 1062 return StmtError(); 1063 } 1064 1065 // Otherwise, verify that this result type matches the previous one. We are 1066 // pickier with blocks than for normal functions because we don't have GCC 1067 // compatibility to worry about here. 1068 if (CurBlock->ReturnType->isVoidType()) { 1069 if (RetValExp) { 1070 Diag(ReturnLoc, diag::err_return_block_has_expr); 1071 RetValExp->Destroy(Context); 1072 RetValExp = 0; 1073 } 1074 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1075 } 1076 1077 if (!RetValExp) 1078 return StmtError(Diag(ReturnLoc, diag::err_block_return_missing_expr)); 1079 1080 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1081 // we have a non-void block with an expression, continue checking 1082 1083 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1084 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1085 // function return. 1086 1087 // In C++ the return statement is handled via a copy initialization. 1088 // the C version of which boils down to CheckSingleAssignmentConstraints. 1089 OwningExprResult Res = PerformCopyInitialization( 1090 InitializedEntity::InitializeResult(ReturnLoc, 1091 FnRetType), 1092 SourceLocation(), 1093 Owned(RetValExp)); 1094 if (Res.isInvalid()) { 1095 // FIXME: Cleanup temporaries here, anyway? 1096 return StmtError(); 1097 } 1098 1099 RetValExp = Res.takeAs<Expr>(); 1100 if (RetValExp) 1101 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1102 } 1103 1104 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1105} 1106 1107/// IsReturnCopyElidable - Whether returning @p RetExpr from a function that 1108/// returns a @p RetType fulfills the criteria for copy elision (C++0x 12.8p15). 1109static bool IsReturnCopyElidable(ASTContext &Ctx, QualType RetType, 1110 Expr *RetExpr) { 1111 QualType ExprType = RetExpr->getType(); 1112 // - in a return statement in a function with ... 1113 // ... a class return type ... 1114 if (!RetType->isRecordType()) 1115 return false; 1116 // ... the same cv-unqualified type as the function return type ... 1117 if (!Ctx.hasSameUnqualifiedType(RetType, ExprType)) 1118 return false; 1119 // ... the expression is the name of a non-volatile automatic object ... 1120 // We ignore parentheses here. 1121 // FIXME: Is this compliant? 1122 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(RetExpr->IgnoreParens()); 1123 if (!DR) 1124 return false; 1125 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 1126 if (!VD) 1127 return false; 1128 return VD->hasLocalStorage() && !VD->getType()->isReferenceType() 1129 && !VD->getType().isVolatileQualified(); 1130} 1131 1132Action::OwningStmtResult 1133Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprArg rex) { 1134 Expr *RetValExp = rex.takeAs<Expr>(); 1135 if (CurBlock) 1136 return ActOnBlockReturnStmt(ReturnLoc, RetValExp); 1137 1138 QualType FnRetType; 1139 if (const FunctionDecl *FD = getCurFunctionDecl()) { 1140 FnRetType = FD->getResultType(); 1141 if (FD->hasAttr<NoReturnAttr>() || 1142 FD->getType()->getAs<FunctionType>()->getNoReturnAttr()) 1143 Diag(ReturnLoc, diag::warn_noreturn_function_has_return_expr) 1144 << getCurFunctionOrMethodDecl()->getDeclName(); 1145 } else if (ObjCMethodDecl *MD = getCurMethodDecl()) 1146 FnRetType = MD->getResultType(); 1147 else // If we don't have a function/method context, bail. 1148 return StmtError(); 1149 1150 if (FnRetType->isVoidType()) { 1151 if (RetValExp && !RetValExp->isTypeDependent()) { 1152 // C99 6.8.6.4p1 (ext_ since GCC warns) 1153 unsigned D = diag::ext_return_has_expr; 1154 if (RetValExp->getType()->isVoidType()) 1155 D = diag::ext_return_has_void_expr; 1156 1157 // return (some void expression); is legal in C++. 1158 if (D != diag::ext_return_has_void_expr || 1159 !getLangOptions().CPlusPlus) { 1160 NamedDecl *CurDecl = getCurFunctionOrMethodDecl(); 1161 Diag(ReturnLoc, D) 1162 << CurDecl->getDeclName() << isa<ObjCMethodDecl>(CurDecl) 1163 << RetValExp->getSourceRange(); 1164 } 1165 1166 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1167 } 1168 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1169 } 1170 1171 if (!RetValExp && !FnRetType->isDependentType()) { 1172 unsigned DiagID = diag::warn_return_missing_expr; // C90 6.6.6.4p4 1173 // C99 6.8.6.4p1 (ext_ since GCC warns) 1174 if (getLangOptions().C99) DiagID = diag::ext_return_missing_expr; 1175 1176 if (FunctionDecl *FD = getCurFunctionDecl()) 1177 Diag(ReturnLoc, DiagID) << FD->getIdentifier() << 0/*fn*/; 1178 else 1179 Diag(ReturnLoc, DiagID) << getCurMethodDecl()->getDeclName() << 1/*meth*/; 1180 return Owned(new (Context) ReturnStmt(ReturnLoc, (Expr*)0)); 1181 } 1182 1183 if (!FnRetType->isDependentType() && !RetValExp->isTypeDependent()) { 1184 // we have a non-void function with an expression, continue checking 1185 1186 // C99 6.8.6.4p3(136): The return statement is not an assignment. The 1187 // overlap restriction of subclause 6.5.16.1 does not apply to the case of 1188 // function return. 1189 1190 // C++0x 12.8p15: When certain criteria are met, an implementation is 1191 // allowed to omit the copy construction of a class object, [...] 1192 // - in a return statement in a function with a class return type, when 1193 // the expression is the name of a non-volatile automatic object with 1194 // the same cv-unqualified type as the function return type, the copy 1195 // operation can be omitted [...] 1196 // C++0x 12.8p16: When the criteria for elision of a copy operation are met 1197 // and the object to be copied is designated by an lvalue, overload 1198 // resolution to select the constructor for the copy is first performed 1199 // as if the object were designated by an rvalue. 1200 // Note that we only compute Elidable if we're in C++0x, since we don't 1201 // care otherwise. 1202 bool Elidable = getLangOptions().CPlusPlus0x ? 1203 IsReturnCopyElidable(Context, FnRetType, RetValExp) : 1204 false; 1205 // FIXME: Elidable 1206 (void)Elidable; 1207 1208 // In C++ the return statement is handled via a copy initialization. 1209 // the C version of which boils down to CheckSingleAssignmentConstraints. 1210 OwningExprResult Res = PerformCopyInitialization( 1211 InitializedEntity::InitializeResult(ReturnLoc, 1212 FnRetType), 1213 SourceLocation(), 1214 Owned(RetValExp)); 1215 if (Res.isInvalid()) { 1216 // FIXME: Cleanup temporaries here, anyway? 1217 return StmtError(); 1218 } 1219 1220 RetValExp = Res.takeAs<Expr>(); 1221 if (RetValExp) 1222 CheckReturnStackAddr(RetValExp, FnRetType, ReturnLoc); 1223 } 1224 1225 if (RetValExp) 1226 RetValExp = MaybeCreateCXXExprWithTemporaries(RetValExp); 1227 return Owned(new (Context) ReturnStmt(ReturnLoc, RetValExp)); 1228} 1229 1230/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently 1231/// ignore "noop" casts in places where an lvalue is required by an inline asm. 1232/// We emulate this behavior when -fheinous-gnu-extensions is specified, but 1233/// provide a strong guidance to not use it. 1234/// 1235/// This method checks to see if the argument is an acceptable l-value and 1236/// returns false if it is a case we can handle. 1237static bool CheckAsmLValue(const Expr *E, Sema &S) { 1238 // Type dependent expressions will be checked during instantiation. 1239 if (E->isTypeDependent()) 1240 return false; 1241 1242 if (E->isLvalue(S.Context) == Expr::LV_Valid) 1243 return false; // Cool, this is an lvalue. 1244 1245 // Okay, this is not an lvalue, but perhaps it is the result of a cast that we 1246 // are supposed to allow. 1247 const Expr *E2 = E->IgnoreParenNoopCasts(S.Context); 1248 if (E != E2 && E2->isLvalue(S.Context) == Expr::LV_Valid) { 1249 if (!S.getLangOptions().HeinousExtensions) 1250 S.Diag(E2->getLocStart(), diag::err_invalid_asm_cast_lvalue) 1251 << E->getSourceRange(); 1252 else 1253 S.Diag(E2->getLocStart(), diag::warn_invalid_asm_cast_lvalue) 1254 << E->getSourceRange(); 1255 // Accept, even if we emitted an error diagnostic. 1256 return false; 1257 } 1258 1259 // None of the above, just randomly invalid non-lvalue. 1260 return true; 1261} 1262 1263 1264Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc, 1265 bool IsSimple, 1266 bool IsVolatile, 1267 unsigned NumOutputs, 1268 unsigned NumInputs, 1269 IdentifierInfo **Names, 1270 MultiExprArg constraints, 1271 MultiExprArg exprs, 1272 ExprArg asmString, 1273 MultiExprArg clobbers, 1274 SourceLocation RParenLoc, 1275 bool MSAsm) { 1276 unsigned NumClobbers = clobbers.size(); 1277 StringLiteral **Constraints = 1278 reinterpret_cast<StringLiteral**>(constraints.get()); 1279 Expr **Exprs = reinterpret_cast<Expr **>(exprs.get()); 1280 StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get()); 1281 StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get()); 1282 1283 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1284 1285 // The parser verifies that there is a string literal here. 1286 if (AsmString->isWide()) 1287 return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character) 1288 << AsmString->getSourceRange()); 1289 1290 for (unsigned i = 0; i != NumOutputs; i++) { 1291 StringLiteral *Literal = Constraints[i]; 1292 if (Literal->isWide()) 1293 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1294 << Literal->getSourceRange()); 1295 1296 llvm::StringRef OutputName; 1297 if (Names[i]) 1298 OutputName = Names[i]->getName(); 1299 1300 TargetInfo::ConstraintInfo Info(Literal->getString(), OutputName); 1301 if (!Context.Target.validateOutputConstraint(Info)) 1302 return StmtError(Diag(Literal->getLocStart(), 1303 diag::err_asm_invalid_output_constraint) 1304 << Info.getConstraintStr()); 1305 1306 // Check that the output exprs are valid lvalues. 1307 Expr *OutputExpr = Exprs[i]; 1308 if (CheckAsmLValue(OutputExpr, *this)) { 1309 return StmtError(Diag(OutputExpr->getLocStart(), 1310 diag::err_asm_invalid_lvalue_in_output) 1311 << OutputExpr->getSourceRange()); 1312 } 1313 1314 OutputConstraintInfos.push_back(Info); 1315 } 1316 1317 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1318 1319 for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) { 1320 StringLiteral *Literal = Constraints[i]; 1321 if (Literal->isWide()) 1322 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1323 << Literal->getSourceRange()); 1324 1325 llvm::StringRef InputName; 1326 if (Names[i]) 1327 InputName = Names[i]->getName(); 1328 1329 TargetInfo::ConstraintInfo Info(Literal->getString(), InputName); 1330 if (!Context.Target.validateInputConstraint(OutputConstraintInfos.data(), 1331 NumOutputs, Info)) { 1332 return StmtError(Diag(Literal->getLocStart(), 1333 diag::err_asm_invalid_input_constraint) 1334 << Info.getConstraintStr()); 1335 } 1336 1337 Expr *InputExpr = Exprs[i]; 1338 1339 // Only allow void types for memory constraints. 1340 if (Info.allowsMemory() && !Info.allowsRegister()) { 1341 if (CheckAsmLValue(InputExpr, *this)) 1342 return StmtError(Diag(InputExpr->getLocStart(), 1343 diag::err_asm_invalid_lvalue_in_input) 1344 << Info.getConstraintStr() 1345 << InputExpr->getSourceRange()); 1346 } 1347 1348 if (Info.allowsRegister()) { 1349 if (InputExpr->getType()->isVoidType()) { 1350 return StmtError(Diag(InputExpr->getLocStart(), 1351 diag::err_asm_invalid_type_in_input) 1352 << InputExpr->getType() << Info.getConstraintStr() 1353 << InputExpr->getSourceRange()); 1354 } 1355 } 1356 1357 DefaultFunctionArrayLvalueConversion(Exprs[i]); 1358 1359 InputConstraintInfos.push_back(Info); 1360 } 1361 1362 // Check that the clobbers are valid. 1363 for (unsigned i = 0; i != NumClobbers; i++) { 1364 StringLiteral *Literal = Clobbers[i]; 1365 if (Literal->isWide()) 1366 return StmtError(Diag(Literal->getLocStart(),diag::err_asm_wide_character) 1367 << Literal->getSourceRange()); 1368 1369 llvm::StringRef Clobber = Literal->getString(); 1370 1371 if (!Context.Target.isValidGCCRegisterName(Clobber)) 1372 return StmtError(Diag(Literal->getLocStart(), 1373 diag::err_asm_unknown_register_name) << Clobber); 1374 } 1375 1376 constraints.release(); 1377 exprs.release(); 1378 asmString.release(); 1379 clobbers.release(); 1380 AsmStmt *NS = 1381 new (Context) AsmStmt(Context, AsmLoc, IsSimple, IsVolatile, MSAsm, 1382 NumOutputs, NumInputs, Names, Constraints, Exprs, 1383 AsmString, NumClobbers, Clobbers, RParenLoc); 1384 // Validate the asm string, ensuring it makes sense given the operands we 1385 // have. 1386 llvm::SmallVector<AsmStmt::AsmStringPiece, 8> Pieces; 1387 unsigned DiagOffs; 1388 if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) { 1389 Diag(getLocationOfStringLiteralByte(AsmString, DiagOffs), DiagID) 1390 << AsmString->getSourceRange(); 1391 DeleteStmt(NS); 1392 return StmtError(); 1393 } 1394 1395 // Validate tied input operands for type mismatches. 1396 for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) { 1397 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1398 1399 // If this is a tied constraint, verify that the output and input have 1400 // either exactly the same type, or that they are int/ptr operands with the 1401 // same size (int/long, int*/long, are ok etc). 1402 if (!Info.hasTiedOperand()) continue; 1403 1404 unsigned TiedTo = Info.getTiedOperand(); 1405 Expr *OutputExpr = Exprs[TiedTo]; 1406 Expr *InputExpr = Exprs[i+NumOutputs]; 1407 QualType InTy = InputExpr->getType(); 1408 QualType OutTy = OutputExpr->getType(); 1409 if (Context.hasSameType(InTy, OutTy)) 1410 continue; // All types can be tied to themselves. 1411 1412 // Int/ptr operands have some special cases that we allow. 1413 if ((OutTy->isIntegerType() || OutTy->isPointerType()) && 1414 (InTy->isIntegerType() || InTy->isPointerType())) { 1415 1416 // They are ok if they are the same size. Tying void* to int is ok if 1417 // they are the same size, for example. This also allows tying void* to 1418 // int*. 1419 uint64_t OutSize = Context.getTypeSize(OutTy); 1420 uint64_t InSize = Context.getTypeSize(InTy); 1421 if (OutSize == InSize) 1422 continue; 1423 1424 // If the smaller input/output operand is not mentioned in the asm string, 1425 // then we can promote it and the asm string won't notice. Check this 1426 // case now. 1427 bool SmallerValueMentioned = false; 1428 for (unsigned p = 0, e = Pieces.size(); p != e; ++p) { 1429 AsmStmt::AsmStringPiece &Piece = Pieces[p]; 1430 if (!Piece.isOperand()) continue; 1431 1432 // If this is a reference to the input and if the input was the smaller 1433 // one, then we have to reject this asm. 1434 if (Piece.getOperandNo() == i+NumOutputs) { 1435 if (InSize < OutSize) { 1436 SmallerValueMentioned = true; 1437 break; 1438 } 1439 } 1440 1441 // If this is a reference to the input and if the input was the smaller 1442 // one, then we have to reject this asm. 1443 if (Piece.getOperandNo() == TiedTo) { 1444 if (InSize > OutSize) { 1445 SmallerValueMentioned = true; 1446 break; 1447 } 1448 } 1449 } 1450 1451 // If the smaller value wasn't mentioned in the asm string, and if the 1452 // output was a register, just extend the shorter one to the size of the 1453 // larger one. 1454 if (!SmallerValueMentioned && 1455 OutputConstraintInfos[TiedTo].allowsRegister()) 1456 continue; 1457 } 1458 1459 Diag(InputExpr->getLocStart(), 1460 diag::err_asm_tying_incompatible_types) 1461 << InTy << OutTy << OutputExpr->getSourceRange() 1462 << InputExpr->getSourceRange(); 1463 DeleteStmt(NS); 1464 return StmtError(); 1465 } 1466 1467 return Owned(NS); 1468} 1469 1470Action::OwningStmtResult 1471Sema::ActOnObjCAtCatchStmt(SourceLocation AtLoc, 1472 SourceLocation RParen, DeclPtrTy Parm, 1473 StmtArg Body, StmtArg catchList) { 1474 Stmt *CatchList = catchList.takeAs<Stmt>(); 1475 ParmVarDecl *PVD = cast_or_null<ParmVarDecl>(Parm.getAs<Decl>()); 1476 1477 // PVD == 0 implies @catch(...). 1478 if (PVD) { 1479 // If we already know the decl is invalid, reject it. 1480 if (PVD->isInvalidDecl()) 1481 return StmtError(); 1482 1483 if (!PVD->getType()->isObjCObjectPointerType()) 1484 return StmtError(Diag(PVD->getLocation(), 1485 diag::err_catch_param_not_objc_type)); 1486 if (PVD->getType()->isObjCQualifiedIdType()) 1487 return StmtError(Diag(PVD->getLocation(), 1488 diag::err_illegal_qualifiers_on_catch_parm)); 1489 } 1490 1491 ObjCAtCatchStmt *CS = new (Context) ObjCAtCatchStmt(AtLoc, RParen, 1492 PVD, Body.takeAs<Stmt>(), CatchList); 1493 return Owned(CatchList ? CatchList : CS); 1494} 1495 1496Action::OwningStmtResult 1497Sema::ActOnObjCAtFinallyStmt(SourceLocation AtLoc, StmtArg Body) { 1498 return Owned(new (Context) ObjCAtFinallyStmt(AtLoc, 1499 static_cast<Stmt*>(Body.release()))); 1500} 1501 1502Action::OwningStmtResult 1503Sema::ActOnObjCAtTryStmt(SourceLocation AtLoc, 1504 StmtArg Try, StmtArg Catch, StmtArg Finally) { 1505 CurFunctionNeedsScopeChecking = true; 1506 return Owned(new (Context) ObjCAtTryStmt(AtLoc, Try.takeAs<Stmt>(), 1507 Catch.takeAs<Stmt>(), 1508 Finally.takeAs<Stmt>())); 1509} 1510 1511Action::OwningStmtResult 1512Sema::ActOnObjCAtThrowStmt(SourceLocation AtLoc, ExprArg expr,Scope *CurScope) { 1513 Expr *ThrowExpr = expr.takeAs<Expr>(); 1514 if (!ThrowExpr) { 1515 // @throw without an expression designates a rethrow (which much occur 1516 // in the context of an @catch clause). 1517 Scope *AtCatchParent = CurScope; 1518 while (AtCatchParent && !AtCatchParent->isAtCatchScope()) 1519 AtCatchParent = AtCatchParent->getParent(); 1520 if (!AtCatchParent) 1521 return StmtError(Diag(AtLoc, diag::error_rethrow_used_outside_catch)); 1522 } else { 1523 QualType ThrowType = ThrowExpr->getType(); 1524 // Make sure the expression type is an ObjC pointer or "void *". 1525 if (!ThrowType->isObjCObjectPointerType()) { 1526 const PointerType *PT = ThrowType->getAs<PointerType>(); 1527 if (!PT || !PT->getPointeeType()->isVoidType()) 1528 return StmtError(Diag(AtLoc, diag::error_objc_throw_expects_object) 1529 << ThrowExpr->getType() << ThrowExpr->getSourceRange()); 1530 } 1531 } 1532 return Owned(new (Context) ObjCAtThrowStmt(AtLoc, ThrowExpr)); 1533} 1534 1535Action::OwningStmtResult 1536Sema::ActOnObjCAtSynchronizedStmt(SourceLocation AtLoc, ExprArg SynchExpr, 1537 StmtArg SynchBody) { 1538 CurFunctionNeedsScopeChecking = true; 1539 1540 // Make sure the expression type is an ObjC pointer or "void *". 1541 Expr *SyncExpr = static_cast<Expr*>(SynchExpr.get()); 1542 if (!SyncExpr->getType()->isObjCObjectPointerType()) { 1543 const PointerType *PT = SyncExpr->getType()->getAs<PointerType>(); 1544 if (!PT || !PT->getPointeeType()->isVoidType()) 1545 return StmtError(Diag(AtLoc, diag::error_objc_synchronized_expects_object) 1546 << SyncExpr->getType() << SyncExpr->getSourceRange()); 1547 } 1548 1549 return Owned(new (Context) ObjCAtSynchronizedStmt(AtLoc, 1550 SynchExpr.takeAs<Stmt>(), 1551 SynchBody.takeAs<Stmt>())); 1552} 1553 1554/// ActOnCXXCatchBlock - Takes an exception declaration and a handler block 1555/// and creates a proper catch handler from them. 1556Action::OwningStmtResult 1557Sema::ActOnCXXCatchBlock(SourceLocation CatchLoc, DeclPtrTy ExDecl, 1558 StmtArg HandlerBlock) { 1559 // There's nothing to test that ActOnExceptionDecl didn't already test. 1560 return Owned(new (Context) CXXCatchStmt(CatchLoc, 1561 cast_or_null<VarDecl>(ExDecl.getAs<Decl>()), 1562 HandlerBlock.takeAs<Stmt>())); 1563} 1564 1565class TypeWithHandler { 1566 QualType t; 1567 CXXCatchStmt *stmt; 1568public: 1569 TypeWithHandler(const QualType &type, CXXCatchStmt *statement) 1570 : t(type), stmt(statement) {} 1571 1572 // An arbitrary order is fine as long as it places identical 1573 // types next to each other. 1574 bool operator<(const TypeWithHandler &y) const { 1575 if (t.getAsOpaquePtr() < y.t.getAsOpaquePtr()) 1576 return true; 1577 if (t.getAsOpaquePtr() > y.t.getAsOpaquePtr()) 1578 return false; 1579 else 1580 return getTypeSpecStartLoc() < y.getTypeSpecStartLoc(); 1581 } 1582 1583 bool operator==(const TypeWithHandler& other) const { 1584 return t == other.t; 1585 } 1586 1587 QualType getQualType() const { return t; } 1588 CXXCatchStmt *getCatchStmt() const { return stmt; } 1589 SourceLocation getTypeSpecStartLoc() const { 1590 return stmt->getExceptionDecl()->getTypeSpecStartLoc(); 1591 } 1592}; 1593 1594/// ActOnCXXTryBlock - Takes a try compound-statement and a number of 1595/// handlers and creates a try statement from them. 1596Action::OwningStmtResult 1597Sema::ActOnCXXTryBlock(SourceLocation TryLoc, StmtArg TryBlock, 1598 MultiStmtArg RawHandlers) { 1599 unsigned NumHandlers = RawHandlers.size(); 1600 assert(NumHandlers > 0 && 1601 "The parser shouldn't call this if there are no handlers."); 1602 Stmt **Handlers = reinterpret_cast<Stmt**>(RawHandlers.get()); 1603 1604 llvm::SmallVector<TypeWithHandler, 8> TypesWithHandlers; 1605 1606 for (unsigned i = 0; i < NumHandlers; ++i) { 1607 CXXCatchStmt *Handler = llvm::cast<CXXCatchStmt>(Handlers[i]); 1608 if (!Handler->getExceptionDecl()) { 1609 if (i < NumHandlers - 1) 1610 return StmtError(Diag(Handler->getLocStart(), 1611 diag::err_early_catch_all)); 1612 1613 continue; 1614 } 1615 1616 const QualType CaughtType = Handler->getCaughtType(); 1617 const QualType CanonicalCaughtType = Context.getCanonicalType(CaughtType); 1618 TypesWithHandlers.push_back(TypeWithHandler(CanonicalCaughtType, Handler)); 1619 } 1620 1621 // Detect handlers for the same type as an earlier one. 1622 if (NumHandlers > 1) { 1623 llvm::array_pod_sort(TypesWithHandlers.begin(), TypesWithHandlers.end()); 1624 1625 TypeWithHandler prev = TypesWithHandlers[0]; 1626 for (unsigned i = 1; i < TypesWithHandlers.size(); ++i) { 1627 TypeWithHandler curr = TypesWithHandlers[i]; 1628 1629 if (curr == prev) { 1630 Diag(curr.getTypeSpecStartLoc(), 1631 diag::warn_exception_caught_by_earlier_handler) 1632 << curr.getCatchStmt()->getCaughtType().getAsString(); 1633 Diag(prev.getTypeSpecStartLoc(), 1634 diag::note_previous_exception_handler) 1635 << prev.getCatchStmt()->getCaughtType().getAsString(); 1636 } 1637 1638 prev = curr; 1639 } 1640 } 1641 1642 // FIXME: We should detect handlers that cannot catch anything because an 1643 // earlier handler catches a superclass. Need to find a method that is not 1644 // quadratic for this. 1645 // Neither of these are explicitly forbidden, but every compiler detects them 1646 // and warns. 1647 1648 CurFunctionNeedsScopeChecking = true; 1649 RawHandlers.release(); 1650 return Owned(CXXTryStmt::Create(Context, TryLoc, 1651 static_cast<Stmt*>(TryBlock.release()), 1652 Handlers, NumHandlers)); 1653} 1654